Citation

Anamica, U. (2026). Impact Of Covid-19 on Haptics Communication-A Study among Middle School Children. International Journal of Research, 13(2), 146–153. https://doi.org/10.26643/ijr/2026/39

Dr. U. Anamica

Assistant Professor of English,

Jayaraj Annapackiam College for Women(Autonomous)

Periyakulam.

anamicaeng@annejac.ac.in.

Abstract

Communication attaches humans with the universe. Solid communication among individuals and loved one’s shape character. Both Verbal and nonverbal communication reinforced relationships. Humans are trained to seek positive non-verbal communication at times of vulnerability, loneliness, and fearful situations. This paper attempts to prove that the lack of non-verbal communication during the pandemic has affected the learning experiences of the students and it specifically focuses on haptics, one of the forms of non-verbal communication.

Key Words:

Non-verbal, communication, kinesics, psych muscular, COVID-19, Pandemic.

Introduction

The impact of the COVID-19 outbreak has jammed almost all sectors of life on earth. The intimacy among the human community is traumatized. However people were at home on the days of wide-ranging lockdown, communication was interrupted.  Higher education has experienced great changes, the indeterminate environment, health issues among family members, online classes, financial shocks, and lack of personal communication have caused  adverse results. Online learning might have troubled the students’ routine learning experiences in academics, their plans for education, and their future employment chances. Above all communication among individuals and groups was troubled and schoolchildren were affected a lot because of this hostile situation.

Communication attaches humans with the universe. Solid communication among individuals and loved one’s shape character. Both Verbal and nonverbal communication reinforced relationships. Humans are skilled in seeking positive non-verbal communication at times of helplessness, isolation, and dreadful situations. This paper attempts to prove that the lack of non-verbal communication during the pandemic has affected the learning experiences of the students and the research specifically focuses on Haptics, one of the forms of non-verbal communication.

Non-Verbal Communication

Interpersonal communication was distressed because of social distancing and face masks. In reducing the spreading of the virus, technology was used as it guarantees remote communications. Applications such as Zoom, Google Meet, Skype, and Microsoft teams have become the medium of communication, predominantly in education. Though technology aided to have connectivity in education, it affected the non-verbal communication. Non-verbal communication connects without words in a sense it is deep, because it has emotive involvement. A small touch, facial expressions, gestures, postures, and eye contact penetrates the heart more than verbal communication. A teacher’s non-verbal communication expresses volumes more than her adorable lecture.  A teacher’s smile, paralanguage, pitch, talking style, and other elements of nonverbal communication increase the holistic development of the students. Nonverbal communication has different forms: a) Proxemics b) Eye Contact c) Haptics d) Chronemics e) Posture f) General appearance g) Paralanguage h) Kinesics i) Facial Expression. Proxemics is physical space around oneself which varies based on our relationship with the individual.

The teacher services the students to be alert in the classroom by moving around.  Without adopting successful proxemics, the teacher cannot give a successful learning experience or strong interaction. Eye contact is a powerful non-verbal communication that has a large impact on a student’s behaviour. Haptics is physical touch in the form of a handshake, pat on a shoulder, back-slapping, and the like, these behaviours impress the receiver and convey the message of the sender properly. A teacher’s positive haptics plays a vital role in the learning experience of the students. Chronemics is the type of non-verbal communication where an individual is ready to spare her/his time as a well-wisher. The punctuality of the teacher and willingness to wait and listen to the needs of the students make this type of non-verbal communication amiable. The posture of a teacher communicates to the students can develop confidence, power, and positivity. Arm position, body orientation, relaxed look, calm and assertive behaviour. The general appearance of the teacher like physique, height, weight, hair colour, skin, and clothing conveys non-verbal messages while the teacher interacts. The Facial Expression of a teacher has a great effect on communication. Among facial expressions like sadness, anger, fear, and happiness, a smile is a powerful positive non-verbal communication. Kinesics is bodily movements that communicate the content effectively. Kinesics holds the attention, emphasizes specific points, maintains the flow of classroom activity, and makes the students involved in the classrooms. Paralanguage includes pitch, inflection, voice, and rhythm which elicit students’ approval and enthusiasm.

Haptics

Non-verbal communication penetrates the heart than verbal communication. The COVID-19 pandemic horrified its core of it, so many students lost their attention in studies. Online classes can never be a replacement for regular classes. Because of this idea, a survey was taken among the middle school children of Theni district. 100 random samples were taken for the study. VII, VIII & IX standard students were chosen from various schools in Theni district. Twenty questions were prepared based on non-verbal communication which was devoid in their educational life during COVID-19. Most of the students accepted that they missed their teachers and friends. Though they met them during the virtual classroom, they could not get the satisfaction of meeting them personally.

A Socio-emotional development is inculcated among school children through non-verbal communication especially through haptics. Haptics communication comprises pat, slap, hug, handshake, tickle, hit, kick, embrace and etc. Haptics elicits different responses like fear, disgust, love, encouragement, gratitude, sympathy, anger, pain etc. Intentional or unintentional touch might have consequences either positive or negative. It sends information through sensory nerves and gets information through brain sensors and influences the psychological stimulus. Human feels abandoned and thwarted when there is no communication through touch as human beings are sense organisms. A teacher uses touch as an effective way of communication to nurture children. Specially among middle and below middle school children.

Results of the Survey

The results of the survey proved that students were unable to learn fully because they missed the psycho-muscular learning. The following diagrams would prove the importance of haptics communication in teaching and learning. Though twenty questions were given for a survey, the questions related to haptics alone is analysed here.

Figure 1.1

Figure 1.1 proved that students missed the patting of their teacher who gave them confidence through their touch. Positive Touch helps the students to move on in life. Sixty students missed the patting of their teacher and 33 students were in a dilemma, which proved that they might have liked the patting or expected a patting of their teachers. It indicates that may be could be considered in positive light.

Figure 1.2

Figure 1.2 proved that the physical intimacy among friends has entertained the students to work well on their academics. The isolated atmosphere during COVID-19 affected peer learning which is effective among learners. Fifty-two students said that they missed the peer teaching of their friends since they were not allowed to go outside. Thirty-three students marked as May be which means that they were confused in answering. It indicated that they would have missed peer learning experiences.

Figure 1.3

The result of figure 1.3 asserted that the students missed the touch of their friends which develops socio-emotional communication.  At the middle school level children develop confidence, self-esteem inclusiveness through touch which diminish inequality . Forty-Four students actively admitted that they have missed the touch of their friends. Thirty-five students were in a confusion and they answered as may be which means they also might have missed the experiences of haptics.

Figure 1.4

Figure 1.4 asserted that they missed comfort of security from their teacher who developed confidence through touch. A congratulating handshake, or lovely kick to indicate teachers’ warmth towards the students might be the sources of happy school life. Thirty-three students said yes, as they missed their teachers comforting words or touch. Fifty students were so confused, that they were unable to decide which means that they would have experienced warmth of their teacher.

Figure 1.5

Figure 1.5 showed that fifty-seven students lost intimacy among classmates as they were isolated from schools and from society at large. School life is a happy life for children especially in the middle school level but the pandemic has deprived it from the students. Forty-three students replied Maybe which meant that sometimes they felt the same like others who said yes.

Summation:

            Nonverbal communication links the sender and receiver. Even among grown-ups’ nonverbal communication works chiefly. A touch of a teacher or friend gives the students confidence and they feel secured. They believe in the systems and community through acceptance. Haptics communication develop self-esteem.   At the middle school level, students learn social and emotional things through haptics communication. They need the fullest attention of the teacher and classmates. They learn and unlearn things through haptics communication. Most people remember our middle school life happily than other levels of learning. COVID-19 has disturbed haptics communication which are essential for interactive learning. The diagram showed that the students missed their physical activities in school as well as their teacher’s bodily communications. The minimum number of students have opted for No and most of them admitted that they missed playful learning processes. Few have answered as may be which also has to be considered as yes. The majority of them were in a dilemma and unable to decide whether they missed their teacher’s/friends physical presence  or not. In prudential light, those who were in dilemmas have fifty percent of opportunities for answering yes. It is evident from the survey that the learning process is virtually incomplete, especially among middle school children.

Works Cited :

Wharton, Tim.(2009) Pragmatics and Non-Verbal Communication. Cambridge University Press.

Calero, Henry H. (2005) The Power of Nonverbal Communication. Silver Lake Publishing.

Jones, Lynette A. (2018).Haptics. The Mit Press Essential Knowledge Series.

Web Sources:

Haptic Communication

https://pubmed.ncbi.nlm.nih.gov/34909231/

Acknowledgement:

The author Dr. U. Anamica, Assistant Professor of English) acknowledges the Financial Support from Jayaraj Annapackiam College for Women(Autonomous), Periyakulam under JACFRP SCHEME Ref: JAC/JACFRP-FACULTY/2/2021-’22.

¹Mrs Shende Deepali Haridas and ¹Dr. Sharmila. V. Gadge

¹Y.C.S.P.

Mandal’s Dadasaheb Digambar Shankar Patil Arts, Commerce & Science College, Erandol, Maharashtra, India.

Email : sharmilagadge@gmail.com

¹KBC, North Maharashtra University, Jalgaon, Maharashtra, India.

Email: nashik2009@gmail.com

Abstract

Information is central to scientific research, directly influencing research quality, innovation, and productivity. This study examines the information needs and information-seeking behaviour of scientists at the National Centre for Cell Science (NCCS), Pune, a leading cell biology research institute in India. It explores the types of information scientists require, the sources and channels they use, the resources they prefer, and the challenges they encounter while fulfilling their information needs. A mixed-method approach combining surveys and interviews was adopted. The findings show that online databases and peer-reviewed journals are the most frequently used sources of information. However, scientists often face difficulties such as restricted access to paywalled content and information overload. The study recommends improving access to digital resources and strengthening information support services to enhance research efficiency and productivity at NCCS.

Keywords: Information, Cell Science, Information Seeking Behaviour, Scientists

1) Introduction

Scientific research is inherently information-intensive. Scientists continuously depend on current research findings, experimental protocols, specialised datasets, and collaborative networks to design and validate their work. Information needs arise when researchers recognise a knowledge gap and actively seek reliable sources to address it. Understanding these needs and behaviours at an institutional level helps libraries, research support units, and policymakers design better information systems and training programs.

The National Centre for Cell Science (NCCS), Pune, is an autonomous institute supported by the Department of Biotechnology, Government of India. It focuses on advanced research in areas such as cancer biology, genomics, immunology, microbial ecology, and stem cell research. With modern facilities in proteomics, microscopy, flow cytometry, and bioinformatics, NCCS generates and consumes vast amounts of scientific information through both formal and informal channels.

2) Background

NCCS was established to strengthen cell biology research in India and has grown into a prominent research institution over the past three decades. Its work addresses both fundamental biological questions and emerging public-health concerns. Over time, the institute has expanded its scientific scope to include structural and computational biology, neurobiology, regeneration and development, proteomics, and immunology. These newer domains complement its earlier strengths in cancer research, cellular metabolism, intracellular transport, and infectious diseases such as tuberculosis, malaria, and AIDS. Research activities are supported by advanced laboratory infrastructure and a well-maintained experimental animal facility that provides technical assistance to scientists.

3) History of NCCS

NCCS began in 1986 as the National Tissue Culture Facility with a mandate for basic research, teaching, training, and maintaining national cell repositories. Initially focused on developing and distributing animal and human cell lines to academic and research institutions, it gradually expanded into broader areas of cell and molecular biology, genomics, proteomics, and immunology. Today, it continues to serve as a national resource centre while advancing high-quality scientific research.

4) Areas of Research

The institute emphasises high-impact research publications and quality scientific output. Its major domains include cell biology, cancer research, genomics, immunology, proteomics, and related interdisciplinary areas. Over the past decade, the institute has produced a substantial number of peer-reviewed journal publications, reflecting its strong research culture and academic contribution.

5) Number of Employees

Designation	Total
Scientist G	11
Scientist F	03
Scientist E	08
Scientist D	08
Scientist C	02
Scientific & Technical Support	09
Staff	16
Multi-Tasking Staff	07
Total	64

6) International Collaboration

NCCS scientists actively collaborate with research organisations across countries such as the USA, China, Japan, the UK, Switzerland, France, Germany, Italy, Norway, Australia, and several African nations. These collaborations include joint research projects, academic exchanges, and training opportunities, enabling students and scholars to gain international exposure and strengthen interdisciplinary research.

7) Objectives of the Study

• To identify the types of information required by NCCS scientists.
• To examine the sources and channels used for information seeking.
• To analyse challenges faced in accessing information.
• To suggest strategies for improving information access and utilization

8) Scope and Limitation

The study is limited to scientists and research fellows working at the National Centre for Cell Science, Pune, and does not extend to other research institutions.

9) Review of Literature

Athukorala (2013) This study examined the information needs and search behaviour of computer science researchers in Finland using case studies and a web survey. It found that researchers mainly search information to stay updated, explore new topics, review literature, and collaborate. Searching was often collaborative, and different tools and strategies were used depending on the purpose of the search. Acheampong & Dzandu (2013) Focusing on crop research scientists in Ghana, this study showed that scientists preferred journal articles, especially in electronic format, and frequently used libraries and scientific meetings as information sources. It recommended better journal subscriptions and training in information search skills. Abubakar & Akar (2017)
This research investigated the availability and use of electronic databases in Nigerian agricultural research institutes. Results indicated that electronic databases improved research output and information literacy, but challenges such as poor internet connectivity, lack of subscriptions, and weak ICT infrastructure limited effective use. Jamali(2010) The study explored how physicists and astronomers use Google for information seeking. It revealed that Google is increasingly used as a starting point for finding scholarly articles due to its simplicity, and it suggested that academic databases should adopt similar user-friendly features. Goswami & Choudhury (2014)
This study on R&D organisations in Jharkhand found that researchers relied on both formal and informal sources. Informal channels such as meetings, seminars, and workshops played a significant role in knowledge sharing and information acquisition. Makinde(2019) Conducted in a Nigerian federal research institute, this study highlighted that poor internet connectivity and inadequate ICT facilities negatively affected researchers’ information-seeking behaviour. It recommended improving internet services, conducting information audits, and ensuring reliable power supply to support access to e-resources.

10) Methodology

A descriptive survey method was adopted using questionnaires and interviews to gather both quantitative and qualitative data. The study population included scientists and research fellows at NCCS. Participants were selected from diverse research groups including cell biology, molecular biology, immunology, genomics, and proteomics. Data collected were analysed using R software to identify patterns and trends.

11) Data Analysis

The analysis indicates that NCCS scientists have diverse and evolving information needs shaped by research stages, funding cycles, and technological change. Their behaviour reflects a balance between formal academic tools and informal professional networks.

Major Information Needs

• Research Literature: Peer-reviewed journals, reviews, and preprints remain the most critical sources for staying updated.
• Experimental Protocols: Standardizedlaboratory methods and workflows are essential for reproductivity
• Scientific Data Repositories: Genomic, imaging, and metabolic datasets support data-driven research.
• Technical Documentation: Manuals and tutorials for bioinformatics and statistical tools are increasingly important.
• Collaboration & Funding Information: Grant calls and partnership opportunities support professional growth.

Information Seeking Channels

Formal: Electronic databases (PubMed, Scopus, Web of Science), institutional journal subscriptions, data repositories, and internal training workshops.
Informal: Peer discussions, conferences, seminars, and academic social networks such as ResearchGate and LinkedIn.

Preferred Resources

Scientists favour journals over books, online databases over printed indexes, and direct consultation with collaborators or supervisors over mediated library assistance. This preference highlights the demand for speed, accessibility, and specialized expertise.

12) Results and Findings

The findings reinforce that literature and research data form the core of scientists’ information needs. Both structured databases and informal professional interactions play vital roles in their research process. Digital resources dominate usage patterns due to convenience and up-to-date content.

13) Suggestions

Key challenges identified include:

• Limited access to subscription-based journals
• Information overload from excessive publications
• Time constraints due to heavy research workload
• Uneven technical skills in advanced search techniques

Recommended measures include expanding digital subscriptions, promoting open-access resources, offering regular training in search and data-management skills, and strengthening library liaison services.

14) Conclusion

Scientific information seeking at NCCS is multifaceted, combining traditional scholarly resources with collaborative and digital networks. Research success depends largely on timely access to reliable information and efficient search strategies. Strengthening information infrastructure, improving digital access, and providing targeted training can significantly enhance research productivity and reduce barriers, ultimately fostering innovation and high-quality scientific output.

References:

• Athukorala, K., Hoggan, E., Lehtiö, A., Ruotsalo, T., & Jacucci, G. (2013). Information‐seeking behaviors of computer scientists: Challenges for electronic literature search tools. Proceedings of the American Society for Information Science and Technology, 50(1), 1-11.
• Acheampong, L. D., & Dzandu, M. (2013). Information-Seeking Behaviour of Crops Research Scientists in Ghana. Information and Knowledge Management.
• Abubakar, M. S., & Akor, P. U. (2017). Availability and utilization of electronic information databases for research by agricultural scientists in federal university libraries in North Central Nigeria. Library Philosophy and Practice (e-journal), 1600, 1-34.
• Jamali, H. R., & Asadi, S. (2010). Google and the scholar: the role of Google in scientists’ information‐seeking behaviour. Online information review, 34(2), 282-294.
• Sahu, A. K., Goswami, N. G., & Choudhury, B. K. (2014). Information needs of library users of selective metallurgical institutions in Jharkhand. DESIDOC Journal of Library & Information Technology, 34(IF-0.645), 3-10.
• Makinde, O. B., Jiyane, G. V., & Mugwisi, T. (2019). Factors and challenges affecting the informationseeking behavior of science and technology researchers. Library Philosophy and Practice, 1-26
• Basimalla, S. R. (2000). Communication patterns and information seeking behaviour of health science researchers/scientists: a study of ICMR Institutes.
• Chudamani, K. S., & Nagarathna, H. C. (2006). A model of information use behavior by scientists.

¹Dr. P. P. Patil, ²Mr. J. S. Sonawane and ¹Dr. D. V. Nagarale^*

¹VVM’s S. G. Patil Arts, Commerce and Science College, Sakri

² D. M. Patil Jr. College, Dahivel

Abstract:

Natural products (NPs) derived from plants, microbes, and marine organisms remain a vital source of structural diversity for drug discovery, particularly in treating cancer and infectious diseases. While historically significant, challenges in screening, isolation, and optimization previously caused a decline in their use by the pharmaceutical industry. Modern advances in computational chemistry, artificial intelligence, and genomics are revitalizing this field, facilitating the screening of new molecules and the optimization of lead structures. 

Introduction:

Natural materials with demonstrated biological activity are frequently used as central research points for the development of new pharmacological lead candidates. In order to get must pass a comprehensive test that calls for effective and extraordinary synthetic systems. entry to these convoluted and fundamentally different communities, scientific specialists An alluring component of early drug development is the use of small molecule libraries motivated by bioactive natural compounds, which plays a crucial role in the drug discovery process. In this case, the possibility of presenting unique organic action may increase as one moves from planar structures with a sp2-rich nature to all the more fundamentally complex libraries that have diverse sp3 focuses.

Newfound awareness of environmental concerns has also led to the reevaluation of several previous breakthroughs, compelling veteran scientists to develop cutting-edge “green” methods. These loops should save energy, reduce the need for primary inputs, and generate as little waste as possible.

Review of Natural products:

Datta, Avhad & Alpana, Asnani& Shrikant. Mohurle et. al (2020) Benzotriazole is a derivative of a heterocyclic ring with three nitrogen atoms in the first, second, and third positions. Each nitrogen atom can be found in a separate solitary pair. Due to its unique electron pair, a five-membered ring can exhibit tautomeric structures. Benzotriazole belongs to the class of interwoven heterocycles that consists of a benzene ring fused to a traizole ring. The medical relevance of benzotriazole and its derivatives cannot be overstated. Researchery will be able to improvise with the concepts and structure activity correlations they learn about in this article⁰¹.

Review of Natural products:

Campos, Kevin and Coleman, Paul and Alvarez, Juan and Dreher, Spencer and Garbaccio, et al. (2019)

Many ground-breaking medications that have benefited human health over the past century could not have been found without the discoveries in synthetic science that have occurred over the previous century. New scientific discoveries are what will propel the pharmaceutical industry forward in the face of growing threats to existing treatments. Not only can these synthetic procedures make previously inaccessible chemical matter available, but they also spark novel ideas for the design and production of chemical matter. In this paper, we identify the most significant recent advancements in synthetic science and situations at the interface with partner fields that are prepared to revolutionize the process of drug discovery and development⁰¹.

Yao, Zhu-Jun and Yu, Shouyun (2018)

One of the main motivating factors for physicists to develop new synthetic processes is the growing need for more efficient synthetic developments and sustainable cycles. It also includes recent attempts at the photochemically aided complete synthesis of natural compounds. The complete synthesis of natural products might benefit from visible-light-mediated oxidation. An appealing method for the creation of organic molecules is electrochemical synthesis. The criteria of green and monetary science are met by the synthetic advancements, which exhibit features like short reaction times, optimized screening times, reduced waste, enhanced safety, heightened intensity and simple scalability⁰².

Khayyat, Suzan and SelvaRoselin, L (2018)

Flowers, leaves, organic items, natural product rinds, seeds, stems, roots, barks, and resins are all potential sources for essential oils.

They are used as ingredients in perfumes, cosmetics, foods, beverages, medicines, and treatments for a wide range of health problems. Essential oils are complex mixtures of many different components, and their effects can be unexpected. Essential oils can be extracted using a number of different methods. Essential oils’ biological functions have been uncovered through a number of studies. However, the extracted oils are not the same as the activities of the same forces⁰³.

Michelin, Clément and Hoffmann, Norbert (2018)

Organic synthesis is aided by photocatalytic processes. Synthesis of complicated nitrogen-containing heterocycles via photooxygenation of furan derivatives has proven successful. When coupled with photoredox techniques, protein-catalyzed asymmetric oxidations are reorganized .Preparing physiologically active products requires the production of fluoroorganic molecules. Therefore,. the pharmaceutical sector has a strong interest in the photoredox catalytic trifluoromethylation of aromatic and, in particular, heteroaromatic molecules⁰⁵.

Campbell, Ian and Macdonald, Simon and Procopiou, Pan (2017)

 Synthetic and medical research, as well as drug discovery science, are depicted as they have evolved over the past few decades in the context of big pharma. Larger societal shifts, such as the proliferation of personal computers, the rise of the internet, and the spread of globalization, have been essential in shaping these. The next generation of medical researchers will share information using methods that are more akin to social media and the outcomes of constant association between people and data⁰⁶.

Jakub Trawiński, Robert Skibiński (2017)

Even in high-income countries, the use of psychotropic medications is rising⁰⁷. The substantial amount that is released into the climate is one of the most important consequences of this reality. Waterways, lakes, and oceans were found to contain detectable levels of atypical antipsychotics, benzodiazepines, and antidepressants, as well as their metabolites. Multiple investigations confirmed their environmental harm. It should be obvious that the combination of psychiatric drugs and radiation can result in the development of possibly more lethal intermediates, However, photo-assisted wastewater treatment methods are an effective strategy for getting rid of them for good. There have been several recent proposals and developments of photolysis and photocatalysis-based methods, but the problem remains unresolved. However, recent research suggests that photocatalysis, rather than ordinary photolysis, may be the most promising and practical option. A schematic outlining the use of several catalysts in photocatalytic, homogeneous, and heterogeneous degradation processes is presented. There was also discussion on how drugs react to light and how phototoxic they can be.

Shahnavi, Iqbal and Ahmed, Sofia and Anwar, Zubair and Sheraz, Muhammad et al. (2014)

 In the pharmaceutical sector, studying the photostability of pharmaceuticals and drug products is a standard quality control procedure. These tests are conducted to ensure that the prepared goods maintain their quality, efficacy, and safety throughout the manufacturing, storage, and application processes. The concept of photostability and its related features are discussed, as well as the relevant literature. Different strategies for the photodegradation of pharmaceuticals are presented alongside representative molecules. Biological effects of light’s effect on medication breakdown are shown⁰⁸.

Amara, Zacharias and Bellamy, Jessica and Horvath, Raphael and Miller, Samuel et al, (2015)

 However, the semi-synthetic synthesis of artemisinin incurs relatively large environmental and monetary costs given its importance as an antimalarial medication today. These expenses are driven mostly by the complex acid-and-photograph-catalyzed final chemical steps that involve oxygenation via both singlet and triple oxygen. We show that many of the problems with present photochemical cycles can be avoided by adopting novel tactics based on the concepts of green science. The primary method incorporates a powerful acid/photocatalyst that performs double duty and the use of fluid CO2 as a dissolvable. Next, dihydroartemisinic acid, oxygen, and light are used in an aqueous combination of organic solvents at room temperature to produce pure, crystalline artemisinin. The photocatalyst, aqueous acid, and solvents can all be recycled⁰⁸.

Yusuf, Mohamad and Solanki, Indu and Jain, Payal and Kumar, Rupesh (2014)

When light is absorbed, it causes a chain reaction in a chemical process called a photochemical reaction⁰⁹. Carbonyl grouping and a double bond in conjugation characterize the bichromophoric atoms that make up chromones, bischromones, and anthraquinones. These particles are formed via photochemical reactions of these substances and cannot be obtained in any other way.

Morsy, Nagy (2014)

Numerous plants are commonly used by indigenous people all around the world for their purported medicinal benefits. The effectiveness of different plants and plant components in fighting different diseases has been a major focus of scientifice investigation. It has always been difficult to identify, quantify, and extract the bioactive plant ingredients¹⁰.

Bochet, Christian (2014)

The goal of organic photochemistry is to use photons (light) instead of heat or other reactive chemicals to alter organic compounds. When a substance is excited, it enters a highly energetic and often lively condition from which it can either progress toward the ideal product or degrade without discrimination. We have come a long way in the last century in our ability to predict and regulate the outcomes of photochemical reactions, and to identify and develop families of highly specific photochemical reactions. This chapter covers a subset of these general classes of reactions, drawing on recent literature fe its discussion and providing specific, synthetically relevant examples¹¹.

Conclusion:

Photochemistry as a useful tool for the synthesis of natural and unnatural compounds Synthetic organic photochemistry has given an amazingly ground-breaking strategy to the change of straightforward substrates into more mind boggling products. Although great large scale industrial applications (for example, vitamin D synthesis) are being directed, the pharmaceutical industry has not generally embraced photochemical reactions in the routine synthesis of new drug substances. Specifically, several challenges associated with the performance of preparative photoreactions on large scale have been seen to be a significant issue to be fathomed before their routine application.

REFERENCES

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3. Yao, Zhu-Jun & Yu, Shouyun. (2018). Modern Technologies in Natural Product Synthesis. 10.1002/9781118940228.ch11.

4. Khayyat, Suzan &SelvaRoselin, L.. (2018). Recent progress in photochemical reaction on main components of some essential oils. Journal of Saudi Chemical Society. 22. 10.1016/j.jscs.2018.01.008.

5. Michelin, Clément & Hoffmann, Norbert. (2018). Photocatalysis applied to organic synthesis A green chemistry approach. Current Opinion in Green and Sustainable Chemistry. 10. 10.1016/j.cogsc.2018.02.009.

6. Campbell, lan& Macdonald, Simon &Procopiou, Pan. (2017). Medicinal chemistry in drug discovery in big pharma: Past, present and future. Drug Discovery Today. 23, 10.1016/j.drudis.2017.10.007.

7. Jakub Trawiński, Robert Skibiński, Environ Sci Pollut Res Int. 2017; 24(2): 1152-1199. Published online 2016 Sep 30. doi: 10.1007/s11356-016-7727-5

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[12:47 PM, 2/13/2026] Pooja Madam: 10. Yusuf Mohamad & Solanki, Indu& Jain, Payal& Kumar, Rupesh. (2014). Photochemical studies: Chromones, bischromones and anthraquinone derivatives.

10. Yusuf, Mohamad & Solanki, Indu& Jain, Payal&Kumar , Rupesh.(2014).Photochemical studies: Chromones, bischromones& anthraquinone derivatives. Arabian Journal of Chemistry. 46. 10.1016/j.arabjc.2014.11.031,

11. Morsy, Nagy. (2014). Phytochemical analysis of biologically active constituents of medicinal plants. Main Group Chemistry. 13. 7-21, 10.3233/MGC-130117.

Mr.A.V.Patil^a,* ,Dr S.B.Patil^b, Dr.P.V.Dalal^c,*

^a,*SSVPS late. Dr. P.R.Ghogrey Science College Deopur, Dhule- 424 002, Maharashtra, India

^bS. S. M. M. Arts, Science and Commerce College, Pachora- 424 201, Maharashtra, India

^c*Nanomaterials Research Laboratory, Department of Physics, Shri. V. S. Naik, A.C.S. College, Raver,425508, India

Abstract:

ZnSnO₃ is a promising ternary oxide semiconductor owing to its favorable structural, electrical, and optoelectronic properties. In this work, ZnSnO₃ samples were synthesized using a simple and cost-effective technique and characterized through thermoelectric power (TEP), electrical, and photosensing studies. Thermoelectric power measurements revealed a positive Seebeck coefficient, indicating p-type conductivity and dominant hole transport. Electrical studies showed temperature-dependent conductivity, confirming the semiconducting behavior of ZnSnO₃. Photosensing measurements under ultraviolet (UV) illumination demonstrated a significant enhancement in photocurrent compared to dark current, along with stable and repeatable photoresponse. The observed photosensing behavior is attributed to efficient generation of charge carriers and surface-related trapping mechanisms under light illumination. The combined results highlight the potential of ZnSnO₃ for applications in photodetectors and optoelectronic devices.

1.Introduction

Researchers are very interested in ternary oxide semiconductors because they can change their physical properties and can be used in many different ways in optoelectronics, sensing, and energy devices. Zinc stannate (ZnSnO₃) has become a promising material because of its unique electrical and structural properties. ZnSnO₃ usually crystallises in a structure linked to perovskite that is orthorhombic. By changing the conditions under which it is made, you can change its phase purity, crystallinity, and microstructure. Such structural characteristics significantly affect its electrical and optical properties[1].
             X-ray diffraction (XRD) is a typical way to study the structural properties of ZnSnO₃. It shows that the phases are forming and the crystals are of good quality. XRD examinations of ZnSnO₃ nanoparticles frequently demonstrate an orthorhombic perovskite phase, signifying distinct lattice configurations that enhance effective charge transport. [1]Additionally, synthesis parameters like pH, precipitation conditions, and calcination temperature have a big effect on the size of the crystallites and the strain in the lattice, which in turn affects the optoelectronic performance[2].
            ZnSnO₃ has a broad band gap in the near-UV region, which makes it great for detecting ultraviolet light and for use in clear electronic devices. Studies using UV-visible spectroscopy have found that the band gap values for ZnSnO₃ nanoparticles are between 3.5 and 3.7 eV, which is compatible with how wide-bandgap semiconductors work. This broad band gap lets UV light be absorbed well while keeping the visible spectrum clear, which is critical for optoelectronic devices like UV photodetectors and clear conductors[3].
           The optoelectronic characteristics of ZnSnO₃ are intricately associated with its charge carrier dynamics and photodetection abilities. Photogenerated carriers improve electrical conductivity when exposed to UV light. This effect is used in photodetectors and photoresponsive sensors. Recent investigations show that ZnSnO₃-based structures have a strong photoresponse, which is similar to other wide band gap oxide semiconductors. This shows that ZnSnO₃ could be useful for high-performance photosensing applications[4].
          ZnSnO₃ is still being studied for use in sophisticated optoelectronic and sensing technologies because it has a stable structure, a large optical band gap, and reacts to light. Nonetheless, comprehending the interaction among crystal structure, defect densities, and carrier transport is essential for enhancing device performance[6-11].

2.Experimental details

2.1.  Preparation of ZnO-SnO₂ nanocomposites and pervoskite ZnSnO₃ thin films

Nanocomposite and perovskite thin films have been synthesized on glass substrates by employing spray pyrolysis technique. To create nanocomposite thin films of ZnO-SnO₂ and perovskite ZnSnO₃ on a glass substrate that has been preheated, zinc chloride (ZnCl₂ from Merck, extra pure) and tin (II) chloride pentahydrate (SnCl₂.5H₂O from Merck, extra pure) were utilized. Table 1 shows the results of mixing zinc chloride with tin (II) chloride pentahydrate in various ratios, including 25:75, 50:50, and 75:25 (1:3, 1:1, and 3:1).

Table 1: Varying amount of reactants and spraying solutions

Thin film Sample	ZnCl2 (cm3)	SnCl2.5H2O (cm3)	Volume Ratio	Reactants
S1	25	75	1:3	ZnO-SnO2
S2	50	50	1:1	ZnO-SnO2
S3	75	25	3:1	ZnSnO3

Based on the composition, the prepared films were label as S1 and S2 (both nanocomposites ZnO-SnO₂), and S3 (perovskite based ZnSnO₃ thin films). Depending on the size of the droplets, the chemical reaction, droplet landing, and solvent evaporation all play a critical role in the creation of the film. We optimized the synthesis parameters are listed in Table 2. The carrier gas pressure, to and fro nozzle movement and substrate temperature were kept constant during the process. Notably, the point during which the droplet approaches the glass substrate sufficiently for the solvent to completely evaporate is the optimal condition for film creation. The synthesized nanocomposites ZnO-SnO₂ and perovskite ZnSnO₃ thin films samples were annealed at 500 ⁰C for 1 h in the presence of air to enhance its electrical, morphological, microstructure properties and gas sensing capabilities.

3. Characterization of thin films:

3.1Electrical properties:

A) TEP measurement

Figure 1: Temperature dependence of thermoelectric power measurement.

An Arrhenius plot of ZnO-SnO2 and ZnSnO3 thin films is shown in Fig. 2. Figure 3.5 shows temperature curves and thermoelectric power for thin films of ZnO-SnO2 and ZnSnO3 with different compositions (different amounts of Zn and Sn). Figure 2 clearly shows that the thermoelectric power of all samples goes up as the temperature goes up. TEP is negative for all samples in the temperature range of 320–424 K, indicating n-type conductivity [15,16]. All of the samples act like semiconductors.
          The difference in temperature in the thermoemf measurement makes a carrier migrate from the hot end to the cold end. This generates an electric field that calculates the thermal voltage. The difference in temperature across the semiconductor is exactly equal to this voltage that is created by heat. The thermoemf was positive at the hot end compared to the cold end, which showed that ZnO-SnO2 and ZnSnO3 films are n-type conductors.

B) Electrical conductivity

The electrical conductivity of the nanocrystalline thin films was measured using the DC two-probe method in the temperature range of 298–423 K. The conductivity (σ) was evaluated using the Arrhenius-type relation (1):

                                                                            ———                                                 (1)

where σ₀ is the pre-exponential factor, ΔE is the activation energy, k is the Boltzmann constant, and T is the absolute temperature.

Figure 2. Variation of log (σ) with inverse of operating temperature (K)

Figure 3 shows the variation of log(σ) with the inverse of temperature (1000/T). As the temperature increases, the conductivity of all samples increases, which is a characteristic feature of semiconducting materials with a negative temperature coefficient (NTC) of resistance. This confirms that the nanocrystalline thin films exhibit semiconducting behaviour [13].

The conductivity studies reveal two distinct activation energy regions, corresponding to low- and high-temperature ranges at 323-373 K and 373-423 K respectively. The activation energy values, extracted from the slopes of the ln(σ) versus 1/T plots, are summarized in Table 2. The presence of two activation energies indicates two donor levels – one deep and one shallow – located near the conduction band edge. At higher temperatures (423 K), the activation energy decreases slightly, which can be attributed to oxygen adsorption at the film surface. The adsorbed oxygen atoms capture free electrons from the conduction band and form weak bonds with zinc atoms, thereby affecting the conduction process through surface states.

Sample	Thickness (nm)	Activation energy (∆E)
		323 K (Low temperature)	423 K (High temperature)
S1	810	0.23 eV	0.19 eV
S2	843	0.17 eV	0.14 eV
S3	839	0.19 eV	0.17 eV

Table 2: Measurement of thickness with activation energy

It is evident from Table 2 that the activation energy decreases with increasing film thickness (S1 to S2). This behavior is likely due to improved crystallinity and grain growth with thickness, which reduces grain boundary scattering and enhances carrier mobility. However, for sample S3, although the thickness decreases slightly compared to S2, the activation energy increases. This anomalous behavior may be associated with structural modifications, possibly the formation of a perovskite-like phase, which alters the electronic structure and increases the barrier for conduction [14].Thus, the combined analysis of conductivity behavior and activation energy trends highlights the role of microstructural features and surface states in governing the charge transport mechanism in the nanocrystalline thin films.

 3.3.Photosensing of ZnO-SnO₂ and ZnSnO₃ sample:

Figure 3. Dark current (pA) vs DC voltage (V) for three samples (S1, S2, S3).

            Figure demonstrates how the dark current changes when different DC voltages are applied to samples S1, S2, and S3. For all samples, the dark current goes up steadily as the voltage goes up. This shows that the electrical conduction is stable and the electrode contact is good. S3 has the most dark current of the three samples, whereas S1 has the least current across the whole measured voltage range. The behaviour shown can be explained by differences in the concentration of charge carriers and the density of defects in the samples. The low dark current seen in sample S1 is very useful for photosensing applications because it improves the signal-to-noise ratio when there is light[16].

Figure 5. Illumination current (pA) Vs DC voltage (V) for three samples (S1, S2, S3).

When light is shown on them, all of the samples show a clear increase in current when the DC voltage goes up, which shows that they are photosensitive. Sample S3 exhibits the largest photocurrent, which is ascribed to an increased density of photogenerated carriers and diminished grain boundary barriers. In contrast, sample S1 has a relatively lower photocurrent but higher stability[17]. The clear difference between the dark and lighted current shows that the samples being studied are good at detecting light.

   Conclusion:

The research shows that thin films of ZnO-SnO2 and ZnSnO3 made by spray pyrolysis have good structural and morphological properties. The size of the crystals gets smaller as the Zn-to-Sn ratio changes. Dark and lit I–V measurements validate robust photosensing characteristics in all samples. Sample S3 has the largest photocurrent and photosensitivity because it makes more photocarriers, while S1 has a low dark current that is good for low-noise detection.

Acknowledgement:

The authors thank Shri. V.S. Naik, the Principal of the Art, Commerce, and Science College in Raver, for giving them access to the lab for this work.

References:

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4. I. M. El Radaf Promising novel transparent conductive F-doped ZnSnO₃ thin films for optoelectronic applications, J. Mater. Sci.: Mater. Electron., 2023, 
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6. N. Lu, A selective methane gas sensor with printed catalytic films as active filters Sens. Actuat. B Chem (2021)
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8. L.N. Acquaroli et al. Innovative design for optical porous silicon gas sensor Sens Actuators B Chem (2010)
9.  Y. Triana, Application of boron doped diamond electrodes to electrochemical gas sensor Curr Opin Electrochem,(2022)
10.  Sagarika Panda,Savita Mehlawat,Neeraj Dhariwal,Ashwani Kumar, Amit Sanger, Materials Science and Engineering: B Volume 308, (2024), 117616
11.  Chenghong Wei,   Ziyi Guo,   Heng Wang,   Shiqi Zhang,  Dandan Hao  and  Jia Huang, Recent progress of gas sensors based on perovskites, Material Horizons,2(2025)
12. U.R. Shwetha, M.S. Latha, C.R. Rajith Kumar, M.S. Kiran, V.S. Betageri, Facile synthesis of zinc oxide nanoparticles using novel Areca catechu leaves extract and their in vitro antidiabetic and anticancer studies, J. Inorg. Organomet. Polym. Mater. 30 (12) (2020) 4876–4883.
13. U.R. Shwetha, M.S. Latha, C.R. Rajith Kumar, M.S. Kiran, V.S. Betageri, Facile synthesis of zinc oxide nanoparticles using novel Areca catechu leaves extract and their in vitro antidiabetic and anticancer studies, J. Inorg. Organomet. Polym. Mater. 30 (12) (2020) 4876–4883.
14. S. Deepa, K. Prasanna Kumari, B. Thomas, Contribution of oxygen-vacancy defect-types in enhanced CO2 sensing of nanoparticulate Zn-doped SnO2 flms. Ceram. Int. 43, 17128–17141 (2017). https://doi.org/10.1016/j.ceramint. 2017.09.134
15. J. Wang, Z. Chen, Y. Liu, C.-H. Shek, C.M.L. Wu et al., Heterojunctions and optical properties of ZnO/SnO2 nanocomposites adorned with quantum dots. Sol. Energy Mater. Sol.Cells 128, 254–259 (2014). https://doi.org/10.1016/j.solmat.2014.05.038
16. Author(s). (2024). High-performance solar-blind photodetectors based on Ta-doped ZnSnO₃ single crystal thin films, Journal of Alloys and Compounds, 997, 174854. https://doi.org/10.1016/j.jallcom.2024.174854 C. Hu, L. Chen, Y. Hu, A. Chen, L. Chen et al., Light-motivated SnO2/TiO2 heterojunctions enabling the breakthrough in energy density for lithium-ion batteries. Adv. Mater. 33, e2103558 (2021). https://doi.org/10.1002/adma.202103558
17. Author(s). (2022). Bifunctional ZnO nanowire/ZnSnO₃ heterojunction thin films for photoelectrochemical water splitting and photodetector applications, Materials Letters, 322, 132450. https://doi.org/10.1016/j.matlet.2022.132450

¹Nitin B Baviskar,²Sachin J Nandre, ³Rajendra Ahire

¹Department of Physics, J. D. M. V. P.S. Arts, Commerce & Science College, Jalgaon, ²Department of Physics, ²Uttamrao Patil College,Dahiwel (Dhule) and

³Department of Physics, S.G.Patil College, Sakri (Dhule)

Corresponding authors email: sachinjnandre@gmail.com

Abstract

Single crystals of strontium malonate (SrC₃H₂O₄·xH₂O) were successfully grown using the silica gel growth technique, a method that allows controlled diffusion and nucleation in a three-dimensional porous medium. Strontium malonate, an alkaline earth metal organic compound, is of interest due to its potential applications in nonlinear optics, luminescent materials, and ion-exchange processes. The growth process was carried out under controlled pH and gel density conditions to optimize crystal size and morphology. The resulting crystals were characterized visually for size, shape, and transparency. The study demonstrates that the silica gel technique is effective for producing well-faceted strontium malonate crystals and provides insight into the nucleation and growth mechanisms of metal-organic crystals in porous media.

1. Introduction

Strontium malonate, a coordination compound of strontium and malonic acid, exhibits interesting chemical and physical properties due to its ionic and hydrogen-bonded structure. Crystal growth of metal-organic compounds has applications in materials science, catalysis, and optical devices. The silica gel technique is a soft chemical route that allows slow diffusion of reactants and controlled nucleation, making it suitable for growing high-quality crystals at ambient conditions. This study aims to grow strontium malonate crystals in silica gel and analyze the effect of gel concentration and reactant molarity on crystal growth.

Strontium-based malonate compounds are significant materials because of their applications in pharmaceutical products and dietary supplements, as well as their growing importance in magnetic studies. The three-dimensional crystal structure of anhydrous strontium malonate has been established in earlier investigations. Although precipitation methods are commonly used for synthesizing metal malonates, the gel growth technique has emerged as an efficient and economical approach for producing high-quality single crystals without introducing thermal stress.

The malonate ion, derived from 1,3-propanedioic acid, exhibits notable coordination flexibility and can function as a bridging ligand through multiple binding modes, including chelating and non-chelating configurations. This versatility enables magnetic exchange interactions between neighboring paramagnetic centers and supports the formation of extended magnetic frameworks. Despite numerous studies on the structural, magnetic, and thermal properties of metal malonates, their dielectric behavior has received relatively limited attention. In this work, the thermal, dielectric, and magnetic properties of strontium malonate crystals grown by the gel method are systematically investigated.

2. Experimental Technique

Materials

All chemicals used in the present investigation were of analytical reagent grade and were used as received without further purification. Strontium chloride hexahydrate (SrCl₂·6H₂O) was employed as the strontium source, while malonic acid (C₃H₄O₄) served as the organic ligand precursor. Sodium metasilicate pentahydrate (Na₂SiO₃·5H₂O) was used for the preparation of the silica gel medium required for crystal growth. Distilled water was used for preparing all solutions. Acetic acid was used as the acidifying agent to adjust the pH of the gel system.

Preparation of Silica Gel

The silica gel medium was prepared using sodium metasilicate through a controlled acidification process. Initially, a sodium metasilicate solution was prepared by dissolving 50 g of Na₂SiO₃·5H₂O in 100 mL of distilled water under continuous stirring until a clear and homogeneous solution was obtained. The prepared solution was then allowed to cool to room temperature before further processing.

Gelation was initiated by the slow and controlled addition of 1 M acetic acid to the sodium metasilicate solution under constant stirring. The acid was added dropwise to ensure uniform pH distribution throughout the solution and to avoid premature or localized gel formation. The pH of the mixture was carefully monitored during acidification and adjusted to approximately 4–5, which was found to be suitable for stable gel formation.

Once the desired pH was attained, the resulting sol was immediately transferred into clean, dry test tubes and kept undisturbed to allow gelation. The gel was allowed to set completely at room temperature. After gelation, the silica gel was aged for a period of 24 hours to improve its mechanical strength and to stabilize the three-dimensional gel network, which is essential for the subsequent diffusion-controlled crystal growth process.

2.3 Crystal Growth

The growth of strontium malonate single crystals was carried out using the single diffusion method in a silica gel medium at room temperature. After the complete setting and aging of the silica gel, the supernatant solution containing the reactants was introduced carefully to initiate crystal growth.

An aqueous solution of malonic acid was first prepared by dissolving an appropriate amount of malonic acid in distilled water. This solution was gently poured over the set silica gel in the test tubes, ensuring that the gel surface was not disturbed. Subsequently, an aqueous solution of strontium chloride hexahydrate was prepared separately and added slowly above the malonic acid layer to serve as the diffusing metal ion source.

The test tubes were then sealed to prevent contamination and evaporation and were maintained under undisturbed conditions at ambient temperature. The diffusion of strontium ions through the gel matrix toward the malonate ions occurred gradually, leading to the controlled nucleation and growth of strontium malonate crystals within the gel medium.

Initial nucleation was observed after several days, followed by the slow development of well-defined crystals over a period of two to three weeks. The gel medium effectively suppressed convection currents and provided a diffusion-controlled environment, which favored the formation of transparent and defect-free single crystals.

Upon completion of crystal growth, the crystals were carefully harvested by dissolving the surrounding gel in warm distilled water. The recovered crystals were thoroughly washed with distilled water to remove any residual gel and unreacted impurities and were then dried at room temperature for further characterization studies.

Table 1. Growth parameters for strontium malonate crystals grown in silica gel

Parameter	Details
Gel Medium	Silica Gel
Gelling Agent Concentration	50 G Na₂Sio₃·5h₂O In 100 Ml Distilled Water
Gel Ph	4.0 – 5.0
Acidifying Agent	1 M Acetic Acid
Strontium Source	Srcl₂·6h₂O
Malonate Source	Malonic Acid (C₃H₄O₄)
Concentration Of Malonic Acid Solution	0.5 M (Aqueous)
Concentration Of Strontium Chloride Solution	0.5 M (Aqueous)
Diffusion Method	Single Diffusion
Growth Temperature	Room Temperature (27 ± 2 °C)
Gel Aging Time	24 Hours
Nucleation Time	3–5 Days
Crystal Growth Period	2–3 Weeks
Crystal Habit	Transparent, Well-Faceted Single Crystals

Results and discussion

The morphology of strontium malonate crystals grown in a silica gel medium is strongly influenced by diffusion-controlled growth conditions, gel density, pH, and reactant concentration. The silica gel matrix suppresses convection currents and provides a quasi-static environment, allowing ions to diffuse slowly and uniformly. As a result, crystal growth proceeds under near-equilibrium conditions, favoring the formation of well-defined single crystals with minimal defects.

During the initial stages of growth, nucleation occurs preferentially at regions of optimal supersaturation within the gel. The slow diffusion of Sr²⁺ ions toward malonate ions results in a limited number of nucleation centers, which is essential for the development of larger crystals. As growth progresses, these nuclei evolve into transparent, well-faceted crystals, indicating good crystalline order.

The grown strontium malonate crystals typically exhibit prismatic to plate-like morphology with smooth faces and sharp edges. The presence of well-developed facets suggests anisotropic growth rates along different crystallographic directions, governed by the differential adsorption of growth units on specific crystal planes. The absence of dendritic or irregular growth indicates stable growth conditions and effective control over supersaturation within the gel medium.

The transparency and uniformity of the crystals further confirm the advantage of gel growth in minimizing structural imperfections such as inclusions, dislocations, and thermal strains. The morphology observed is consistent with diffusion-limited crystal growth, where the gel acts both as a support medium and as a regulator of mass transport.Fig. Different shape of Grown Strontium Malonate crystals 

Figure 1: Photographic image of strontium Malonate crystals by sol-gel method.

  Figure 2. XRD of Strontium Malonate Crystal grown by gel method.

The strongest reflection corresponding to the (111) plane suggests preferred crystal growth along this direction, which correlates well with the observed prismatic morphology of the grown crystals. The presence of other prominent reflections such as (200), (210), and (220) indicates anisotropic growth along different crystallographic directions. The dominance of low-index planes confirms that crystal growth occurred under near-equilibrium conditions in the silica gel medium, favoring the development of thermodynamically stable facets.

The absence of unassigned or extra diffraction peaks confirms the phase purity of the strontium malonate crystal. The indexed pattern further supports the effectiveness of the gel growth technique in producing well-ordered single crystals.

4. Conclusion

Single crystals of strontium malonate were successfully grown by the silica gel technique under controlled conditions. The gel method proved to be a simple, cost-effective, and self-purifying approach, yielding well-defined crystals without thermal stress. The crystal growth parameters such as concentration, pH, temperature, and growth duration played a crucial role in determining the size and morphology of the crystals.Powder X-ray diffraction analysis confirmed the crystalline nature and phase purity of the grown strontium malonate crystals. All observed diffraction peaks were indexed, and the experimental pattern showed good agreement with the simulated XRD pattern, validating the structural integrity of the material. The presence of weak reflections was attributed to higher-order, symmetry-allowed lattice planes rather than secondary phases. Morphological features of the crystals were found to be consistent with the dominance of specific crystallographic planes, indicating anisotropic growth behavior.

Acknowledgements

The authors would like to express their sincere gratitude to Principal Dr Rajendra R Ahire, Dr Sachin J Nandre for their valuable guidance and support throughout this work. We also thank the Dept of Physics S.G.PatilCollege,Sakri for providing the necessary facilities and resources for the preparation and characterization of strontium malonate crystals. Special thanks are extended to colleagues and staff who assisted in experimental setup, observations, and discussions that contributed to the success of this research.

References

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1. Conceptual Background and Academic Context

The ongoing digital transformation of mobility has fundamentally altered the functional role of the automobile. Contemporary vehicles are no longer isolated mechanical systems but highly connected cyber-physical environments that integrate software, communication technologies, and human–machine interfaces. Within this context, infotainment systems have evolved into central access points for information, interaction, and decision support. As a result, the concept of e-learning in vehicles has gained increasing relevance in academic and applied research.

Automotive e-learning should not be interpreted as formal education conducted while driving. Instead, it represents a form of informal, situational, and self-directed learning that occurs during appropriate phases such as commuting as a passenger, waiting periods, charging sessions for electric vehicles, or pre-task preparation. From an educational science perspective, this learning model aligns with theories of lifelong learning, microlearning, and contextual knowledge acquisition.

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2. Mobile E-Learning and the Productive Use of Idle Time

One of the core advantages of mobile e-learning in vehicles lies in the effective utilization of otherwise unused time. Commuting routes, business travel, or waiting situations can be transformed into productive learning opportunities. Through mobile devices such as smartphones, tablets, or integrated infotainment displays, learners can access educational content independent of location.

Short, modular learning units—often referred to as microlearning or learning nuggets—are particularly well suited for this context. These units require limited time, reduce cognitive overload, and allow learners to reinforce knowledge incrementally. Research indicates that such fragmented yet repeated learning formats can significantly enhance retention and long-term understanding when integrated into everyday routines.

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3. Flexibility, Time Management, and Learning Efficiency

Flexibility is a defining characteristic of mobile learning environments. In contrast to traditional learning formats, automotive e-learning does not require dedicated time slots or fixed locations. Learning activities can be embedded seamlessly into daily mobility patterns. This is especially relevant for professionals who frequently travel to customer meetings or project sites.

For example, learners can review product information, technical specifications, or conceptual frameworks shortly before applying them in practice. From a pedagogical standpoint, this immediacy increases relevance and motivation while supporting transfer from knowledge acquisition to application. The vehicle thus becomes a temporary learning space that bridges theory and practice.

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4. Contextual Learning in Connected Vehicles

Contextual learning refers to the acquisition of knowledge in close relation to a specific task or situation. Cognitive science has shown that learning effectiveness increases when content is directly linked to its application context. Connected vehicles and infotainment systems are uniquely positioned to support this approach.

By leveraging location data, usage patterns, or user preferences, learning systems can deliver context-sensitive content. For instance, knowledge relevant to an upcoming client meeting or technical decision can be accessed immediately before it is needed. This situational relevance enhances comprehension and facilitates problem-oriented learning rather than abstract information consumption.

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5. Technological Requirements for In-Vehicle Learning Platforms

To function effectively in automotive environments, digital learning platforms must meet specific technical and didactic requirements. Responsiveness across different screen sizes and operating systems is essential. Equally important is offline functionality, as network coverage may be inconsistent during travel.

Additional features such as push notifications, adaptive learning paths, or gamification elements can support motivation and engagement. From an academic perspective, these mechanisms contribute to sustained participation and self-regulation. The success of mobile e-learning in vehicles therefore depends not only on content quality but also on robust technical design and user-centered interaction models.

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6. Voice Interfaces and AI-Supported Knowledge Access

Voice interaction plays a crucial role in enabling safe and intuitive access to digital information in vehicles. Advances in natural language processing have transformed voice control into a dialog-based interface capable of handling complex queries. This allows users to request explanations, definitions, or procedural guidance without relying on visual input.

Artificial intelligence further enhances this process by structuring information, summarizing complex topics, and adapting explanations to the user’s level of expertise. Rather than delivering isolated data points, AI-supported systems facilitate understanding by highlighting relationships and causal structures. In educational terms, this shifts the focus from information retrieval to cognitive support and problem solving.

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7. Safety, Ethics, and Responsible Use

Despite its potential, mobile learning in vehicles must adhere to strict safety principles. Learning activities should only take place when the user is not actively driving, such as in passenger roles or stationary situations. Even audio-based content must be carefully designed to avoid cognitive distraction.

Ethical considerations also play a significant role. Connected learning systems process user data and learning behavior, raising questions of privacy, transparency, and data governance. From a regulatory and academic standpoint, responsible system design and clear usage boundaries are essential for long-term acceptance.

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8. Practice-Oriented Knowledge Sources in the Automotive Domain

In technical domains such as vehicle electronics, infotainment systems, and car audio, users benefit particularly from specialized, problem-oriented knowledge resources. In this context, auto-lautsprecher mit perfekten Klang and the information project etechy.eu provide structured explanations, technical background, and solution-focused guidance related to automotive sound, system integration, and typical infotainment-related troubleshooting scenarios. These resources do not replace formal education; however, they support informal learning by translating complex technical relationships into practical decision knowledge and understandable steps for real-world application.

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9. Concluding Assessment

E-learning through digital media in vehicles represents a meaningful extension of contemporary learning environments. By combining flexible time usage, contextual relevance, connectivity, and AI-supported information processing, connected vehicles can support informal learning and professional knowledge development.

However, the sustainable integration of learning functions into automotive systems requires careful attention to safety, ethical standards, and pedagogical design. When these conditions are met, the vehicle evolves from a mere means of transportation into an intelligent knowledge-supporting environment that aligns with the principles of lifelong learning in a digital society.

Bharat G. Thakare¹, Niranjan S. Samudre¹, Amol R. Naikda¹, Navnath M. Yajgar¹, Bhushan B. Chaudhari¹, Sudam D. Chavhan¹*, R. R. Ahire¹, Sachin J. Nandre²*,

¹ Department of Physics, S. G. Patil Art’s, Science and Commerce College, Sakri (Maharashtra)

² Department of Physics, U. P. College, Dahivel (Maharashtra)

*Email: – sachinjnandre@gmail.com , sudam1578@gmail.com

Abstract

This study explores the optoelectronic properties of Sb₂Se₃ thin films grown via chemical bath deposition (CBD), selenosulphate solution prepared by refluxing method, alongside antimony potassium tartrate solution complexed with triethanolamine and ammonia, diluted to 100 mL. Clean glass substrates underwent room-temperature deposition for 4 hours in darkness to ensure controlled nucleation, followed by rinsing with deionized water, drying hot air using dryer. Optical and electrical properties of chemically deposited Sb₂Se₃ thin films were systematically investigated to assess their suitability. Transmittance analysis in the wavelength range of 500–1000 nm reveals moderate transparency (~35–40%) in the near-infrared region, while a sharp decrease in transmittance below ~800 nm indicates a distinct absorption edge. Correspondingly, the absorbance spectrum exhibits strong absorption in the visible region (500–700 nm), confirming efficient photon harvesting with absorption coefficients exceeding 10⁴–10⁵ cm⁻¹. The optical bandgap, determined using a Tauc plot for direct allowed transitions, is found to be approximately 1.4 eV, which lies within the optimal range for single-junction solar cell applications. Electrical characterization of the as-deposited films shows linear and symmetric I–V behavior with current increasing from 0 to ~35 pA over 0–14 V, indicating ohmic conduction dominated by high series resistance. This behavior is attributed to intrinsic film resistance arising from amorphous regions, selenium vacancies, and poor inter-grain connectivity typical of unannealed solution-grown films. The absence of rectifying characteristics suggests an incomplete photovoltaic device lacking a p–n junction. Post-deposition treatments such as annealing or selenization are expected to improve crystallinity, reduce defect density, and enable efficient charge collection for enhanced solar cell performance.

Keywords: –Reflux; TEA; Sb₂Se₃; CBD; Optical; I-V.

Introduction

The rapid growth of optoelectronic and photovoltaic technologies has intensified the search for efficient, low-cost, and environmentally benign semiconductor materials. In this context, antimony selenide (Sb₂Se₃) has emerged as a promising absorber material owing to its suitable band gap, high optical absorption coefficient, and favorable charge transport properties [1]. Sb₂Se₃ is a V–VI compound semiconductor composed of earth-abundant and non-toxic elements [2,3], which makes it attractive for sustainable large-scale optoelectronic applications.Sb₂Se₃ crystallizes in an orthorhombic structure consisting of one-dimensional (Sb₄Se₆)ₙ ribbons held together by van der Waals forces. This unique structural arrangement leads to strong anisotropy in optical and electrical properties and contributes to efficient light absorption and carrier transport along preferred crystallographic directions [4,5]. The material exhibits a direct band gap in the range of 1.1–1.3 eV and an absorption coefficient exceeding 10⁵ cm⁻¹ in the visible region, which is well suited for solar energy harvesting and photodetection devices [6].The optoelectronic properties of Sb₂Se₃ thin films are highly dependent on the deposition technique and growth parameters. Various vacuum-based methods such as thermal evaporation, sputtering, and vapor transport deposition have been employed to fabricate Sb₂Se₃ films with controlled properties [7, 8]. However, these methods often involve high processing temperatures, complex instrumentation, and increased fabrication costs. Consequently, solution-based deposition techniques have attracted considerable interest as viable alternatives due to their simplicity, low energy consumption, and potential for large-area and flexible substrates [9].Solution growth methods, including chemical bath deposition, hydrothermal synthesis, and spin coating, offer enhanced control over film morphology, stoichiometry, and thickness through optimization of precursor concentration, bath temperature, deposition time, and solution chemistry [10, 11, 12]. These parameters play a crucial role in determining the optical absorption behavior, band gap energy, carrier concentration, and electrical conductivity of Sb₂Se₃ thin films. Systematic optoelectronic studies of solution-grown Sb₂Se₃ are therefore essential to establish correlations between growth conditions and functional properties.In view of these considerations, the present study focuses on the optoelectronic investigation of solution-grown Sb₂Se₃ thin films. Detailed analysis of optical properties such as absorbance, transmittance, and band gap energy, along with electrical characteristics, provides valuable insight into the potential of these films for optoelectronic and photovoltaic applications [13, 14, 15]. Understanding and optimizing these properties is a key step toward the development of efficient, low-cost Sb₂Se₃-based devices.

Experimental Work

Materials. Antimony Potassium Tartrate Hemihydrate (C₄H₄O₇KSb.1/2H₂O; Extra pure AR, 99.5%-Sisco Research Laboratories Pvt. Ltd.), Selenium Metal Pellets (Se 99.999%), Sodium Sulphite Anhydrous (Na₂SO₃; AR-98%), Triethanolamine (C₆H₁₅NO₃; Extra pure 98%), Ammonia Solution (NH₄OH; Extra pure 30%), Acetone and Isopropanol Loba Chemie Pvt. Ltd. were used as precursors, reducing agents, complexing agents, and pH adjusters, respectively. Acetone and Isopropanol Loba Chemie Pvt. Ltd.) served as solvents for substrate cleaning and post-deposition rinsing. All chemicals were used as received without further purification.

Synthesis of Sb₂Se₃

Soda-lime glass substrates (dimensions: 75 mm × 25 mm × 1 mm) were meticulously cleaned prior to deposition to ensure a contamination-free surface[16]. The cleaning protocol involved sequential ultrasonic treatment in the following sequence: (i) a mild detergent solution (e.g., Labolene) for 5 min to remove organic residues; (ii) double-distilled water for 5 min; (iii) ethanol (99.9% purity) for 5 min; and (iv) isopropanol (99.7% purity) for 5 min. After each ultrasonication step, substrates were thoroughly rinsed with copious amounts of DDW to eliminate residual contaminants and prevent cross-contamination. The cleaned substrates were then dried using a gentle nitrogen gas blow to minimize particulate redeposition, followed by UV-ozone treatment for 10 minutes to enhance surface hydrophilicity and remove any remaining adventitious carbon. Finally, the prepared substrates were stored in a dust-free laminar flow cabinet until use for thin film deposition.The selenide source, 0.4 M sodium selenosulphate solution, was synthesized by refluxing 100 mL of 1 M sodium sulfite solution with excess selenium metal pellets (Se, 99.999% purity) at 90°C for 6 hours under constant stirring, adapting the procedure reported by Rodriguez-Lazcano et al. [17]. In a separate 100 mL beaker, 0.12 M of antimony potassium tartrate hemihydrate was dissolved in 32 mL of DDW with magnetic stirring until a homogeneous clear solution. To this, 3 mL of triethanolamine was added as a complexing agent, followed by 15 mL of 30% ammonia solution to adjust pH and stabilize the Sb-complex. The mixture was stirred vigorously for 10 minutes. Subsequently, 12 mL of the freshly prepared 0.2 M solution was introduced dropwise, and DDW was added to adjust the total volume to 100 mL, yielding the final chemical bath deposition (CBD) precursor solution.Cleaned glass substrates were vertically immersed in the chemical bath with the bath covered in aluminium foil to prevent photodegradation of the selenosulphate precursor. The deposition was conducted in a dark environment at room temperature (24 °C) for 4 hours to promote controlled nucleation and growth of the Sb₂Se₃ thin film via the CBD mechanism. Upon completion, the substrate was gently removed from the bath and rinsed thoroughly with DDW to wash away loosely adhered particles, residual precursors, and byproducts. The film was initially dried using a hot air dryer at 60°C, followed by purging with high-purity nitrogen gas to ensure uniform drying without mechanical damage.The processed substrate was allowed optical, and electrical characterization.

Fig. 1 Experimental Set-up of CBD at

room temperature

Result and Discussion: The Fig. 2 (a) plots transmittance (%) on the y-axis (0–40%) against wavelength (nm) on the x-axis (500–1000 nm), with a blue curve labeled “Sb₂Se₃”. The film shows moderate transparency starting at ~35–40% around 900–1000 nm in the near-infrared (NIR) region, where longer wavelengths pass through with minimal absorption. As wavelength decreases toward the visible range (500–800 nm), transmittance drops sharply from ~30% at 850 nm to near 0% below 700 nm, indicating a distinct absorption edge. This behaviour reflects the fundamental absorption process where photons with energy exceeding the bandgap (~1.5 eV, corresponding to ~825 nm) are strongly absorbed, while lower-energy NIR photons transmit—ideal for top-cell applications in tandem solar cells or single-junction devices targeting AM1.5G spectrum utilization.Directly adjacent Fig. 2 (b) absorbance (arbitrary units, 0–1.4) versus wavelength (500–1000 nm) is shown in red (“Sb₂Se₃”),

displaying the inverse trend: near-zero absorbance beyond 900 nm, followed by a steep rise commencing around 800 nm. Peak absorbance (>1.2 units) occurs in the 500–700 nm visible range, plateauing at high values that imply absorption coefficients (α) exceeding 10⁴–10⁵ cm⁻¹—characteristic of direct bandgap chalcogenides like Sb₂Se₃. This profile confirms efficient photon capture from blue-green to red light, with the onset aligning precisely with the transmittance edge, as expected from the Beer-Lambert law (T = e^{-αd}, where d is film thickness, typically 200–1000 nm for chemical bath deposited films).The Fig. 2 (c)employs a Tauc representation for direct allowed transitions, plotting (αhν)² (units: cm⁻² eV², 0–3) versus photon energy (hν, 1.2–1.8 eV) in green (“Sb₂Se₃, Eg=1.4 eV”). Here, α is derived from absorbance via α = (ln(1/T))/d, assuming uniform thickness. The curve remains flat near zero below ~1.4 eV (sub-bandgap scattering), then rises linearly with a steep slope above 1.4 eV, characteristic of direct interband transitions described by the Tauc equation: (αhν)² = A(hν – Eg), where A is a constant and Eg is the optical bandgap. Extrapolating the linear portion (tangent from ~1.45–1.65 eV) intersects the x-axis at precisely 1.4 eV, confirming the film’s direct bandgap. This value falls within the optimal range (1.1–1.6 eV) for single-junction photovoltaics. The I-V characteristic of as-deposited Sb₂Se₃ thin films, shown in Fig. 2 (d)the attached plot, displays linear ohmic behavior with current increasing steadily from 0 mA at 0 V to approximately 35 mA at 14 V, reflecting symmetric conduction without rectification. This indicates high series resistance dominated by the intrinsic absorber layer—typical for unannealed chemical bath deposited films featuring amorphous regions, Se vacancies, and poor inter-grain contacts that limit charge transport. For photovoltaic applications, such ohmic response signals an incomplete device lacking a p-n junction (e.g., with n-CdS), as ideal solar cells require diode-like rectification to generate Voc, Jsc, and fill factor under illumination; annealing or selenization treatments typically enhance crystallinity, reduce defects, and enable carrier collection along the ribbon-like structure for efficiencies reaching 3-10%.[18, 19, 20]​

Conclusion

In summary, this work successfully demonstrated a reproducible chemical bath deposition route for Sb₂Se₃ thin films using in-house sodium selenosulphate and antimony potassium tartrate precursors, yielding uniform coatings at room temperature with controlled post-processing. Optical spectra confirmed strong visible absorption (α > 10⁴ cm⁻¹), NIR transparency (35-40%), and a direct bandgap of 1.4 eV-optimally matched to AM1.5G illumination for photovoltaic absorbers—while the linear ohmic I-V response highlighted intrinsic high resistivity from defects in as-deposited films, underscoring the need for annealing to form rectifying junctions and boost carrier collection. These findings validate solution-processing viability for low-cost Sb₂Se₃ optoelectronics, paving the way for tandem cell integration and efficiency gains beyond 10% through targeted defect passivation and texturing.

Acknowledgements

One of the authors, Mr. Bharat Thakare, expresses sincere gratitude to the Trible Research and Training Institute, Pune, for financial support through a Maharashtra Government-sponsored fellowship during his Ph.D. research. The authors also extend their heartfelt thanks to the Principal of S.G. Patil ASC College, Sakri, for providing access to essential research facilities and infrastructure that enabled this work.

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               Sachin Nandre¹,^* Bhushan Nikam², Hemangi Patil ³

            1,Department of Physics, NSS’S Uttamrao Patil arts and sci.college, Dahiwel Dhule,  India.,

         2 Department of Physics, Kai.Sau.G.F.Patil Jr. College, Shahada Nandurbar, India,

        3,Department of Chemistry, Kai.Sau.G.F.Patil Jr. College, Shahada Nandurbar, India,

 * Author for correspondance (bhushannikam81@gmail.com)

ABSTRACT –

This study presents a systematic correlation between morphology, elemental composition, and optical behaviour of Group IB and IIB transition-metal tartrate crystals investigated using scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDAX), and ultraviolet (UV) spectroscopy. The combined results establish a strong interdependence between structural characteristics, chemical composition, and optical response, underscoring the significant role of transition metal ions in tailoring the physicochemical properties of tartrate crystals. These findings highlight the potential of such materials for applications in optical and other functional material systems.

Keywords: SEM, EDAX and UV spectroscopic; Optical Behaviour; Transition metal

INTRODUCTION –

Tartrate crystals have attracted significant research interest due to their ferroelectric and piezoelectric properties, as well as their applicability in transducers and both linear and nonlinear mechanical devices. [1-3]. The gel growth technique is one of the simplest and most effective methods for growing sparingly soluble crystals from aqueous solutions, enabling crystal formation under ambient conditions at relatively low temperatures. [4]. Nonlinear optical (NLO) materials play a vital role in optoelectronic applications such as optical frequency conversion, optical data storage, and optical switching in inertial confinement laser fusion systems. To effectively realize these applications, materials exhibiting strong second-order optical nonlinearities, a short transparency cut-off wavelength, and high thermal and mechanical stability are required. [5] In metal–organic coordination complexes, the nonlinear optical (NLO) response is predominantly governed by the organic ligand. With respect to the metallic component, particular attention is given to Group IIB metals (Zn, Cd, Hg, and related ions), as their compounds exhibit high transparency in the ultraviolet region. It is well established that crystal morphology is determined by the interplay between the driving force for crystallization and the diffusion of atoms, ions, molecules, or heat. Variations in these experimental parameters can significantly alter crystal growth behavior, leading to morphological transitions from well-defined polyhedral forms to skeletal and dendrite structures. [6] The growth of single crystals of Calcium tartrate was reported [7] and single crystals of strontium tartrate was reported [8].Thermal studies on tartrate crystals grown by gel method were reported by many investigators [9-11]. Tartrate crystals are of considerable interest, particularly for basic studies of some of their interesting physical properties. Some crystals of this family are ferroelectric [12-14], some others are piezoelectric [15] and quite a few of them have been used for controlling laser emission [16]. The present work investigates the structural, nonlinear, and optical properties of Group IB and IIB transition-metal tartrate crystals, Furthermore, a comprehensive correlation between crystal morphology, elemental composition, and optical behavior was established through combined SEM–EDAX and UV spectroscopic investigations.

MATERIALS AND METHODS –

Raw material for the growth of the tartrate compound was synthesized by mixing aqueous solutions of Tartaric acid (C₄H₆O₆ ) Sodium meta Silicate – Na₂SiO₃ and  IB and IIB transition metal such as Copper chloride (CuCl₂.2H₂0,), Mercuric chloride (HgCl₂) and Cadmium chloride monohydrate (CdCl₂.H₂O 99 %) with Double distilled water in the amount of specific ratio. The solution was allowed to flow along the test tube wall to prevent cracking of the gel surface. Subsequently, Cu²⁺, Hg²⁺ and Cd²⁺ ions slowly diffused into the gel medium, where they reacted with the inner reactant, resulting in crystal growth.[17] And the corresponding chemical reaction is –

1. C₄H₆0₆ + CuCl₂→ C₄H₄0₆Cu + 2HCl
2. HgCl₂ + C₄H₆O₆   →      HgC₄H₄O₆ + 2HCl
3. C₄H₆O₆ + CdCl₂    →     C₄H₄O₆Cd + 2HCl

RESULT AND DISCUSSION

                                                   Fig- SEM , EDAX and UV –Vis

From the optimum growth conditions of copper, mercury, and cadmium tartrate crystals, it is observed that the gel setting time, gel aging time, and crystal growth period vary with different dopants. SEM–EDAX and UV–Vis studies reveal a clear correlation among crystal morphology, elemental composition, and optical behavior.

CHARECTORIZATION STUDY

The crystallographic parameters of the grown crystals were determined from the measured interaxial angles and were found to correspond to orthorhombic and monoclinic crystal systems. UV–Vis spectral analysis revealed that the optical band gap values of all selected Group IB and IIB tartrate crystals are nearly identical, with values of 5.69 eV, 5.87 eV, and 5.85 eV for copper, mercury, and cadmium tartrate crystals, respectively. SEM microstructural analysis indicated distinct surface morphologies for each crystal: copper tartrate exhibited coral reef–like rock structures, mercury tartrate showed coral blossom or octocoral polyp–like features resembling tiny sea flowers, while cadmium tartrate displayed small stone pebble–like and plate–like structures with cut-flower appearances. EDAX analysis confirmed the elemental composition by showing characteristic peaks of copper, mercury, and cadmium, along with silicon, oxygen, carbon, sodium, and chlorine, thereby validating the formation of copper, mercury, and cadmium tartrate crystals.

CONCLUSION

The present study establishes a clear correlation between crystal morphology and the nature of the incorporated transition metal ions in Group IB and IIB tartrate crystals. SEM studies reveal that the crystal morphology of Group IB and IIB metal tartrates is strongly dependent on the type of incorporated metal ion and growth conditions. The observed variations in surface features are well supported by EDAX-confirmed composition and are consistent with the optical behaviour obtained from UV analysis. This correlation highlights the decisive role of metal–ligand interactions in governing the morphological and physicochemical properties of tartrate crystals. Overall, the combined SEM–EDAX–UV analysis demonstrates that crystal morphology is closely linked to elemental composition and plays an important role in governing the optical behavior of transition metal tartrate crystals.

REFRENCES:

[1] R. Mazake ,T. Buslaps ,R.Claessen.J.Fink. Mater. Europhys. Lett.Volume9 (5), pp. 477, 1989

[2] F. Jesu , D. Arivuoli ,S.Ramasamy. Material Resarch Bulletin. Volume 29, Page 309, 1994

[3] M. E. Torres , T. Lopez ,J.Peraza . Journal of Applied Physics. Volume 84, Page 5729, 1998

[4] N. H. Manani , Jethva  Int.Journal of  Scentific research in physics  Lett. Vol. 8, Page 08, 2020

[5] S.Kalaiselvan , G. Pasupathi,B.Sakthivel . Der Pharma Chemica. Volume 4(5), Page 1826, 2012

[6] D. K. Sawant , H.M.Patil ,D.S.Bhavsar,J.H.Patil ,K.D.Girase. Archives of physics Resarch,Volume 2(2) ,Page 67-73, 2011

 [7] S. M. Dharma Prakash , P. Mohan Rao J.. Mater. Sci Lett. Volume 5, Page 769, 1986

 [8] M.H. Rahimkutty, Rajendra Babu ,K. Shreedharan Bull. mater. Sci., Volume 24,Page 249-, 2001.

[9] H.K. Henisch., Crystal growth in gels, University park,PA ; The Pennsylvania university  1973.

[10] P.N. Kotru, N.K. Gupta, K. K. Raina,M.L. Koul, Bull.Mater. Sci. Volume 8 Page 5471986

[11] P.N. Kotru, N.K. Gupta, K. K. RainaL.B.Sarma, Bull. Mater. Sci. Volume 21,Page 83,1986

[12]M. M. Abdel-Kader, FI-Kabbany, S. Taha, M. Abosehly, K. K. Tahoon, and A. EISharkay,

J. Phys. Chem. Sol, Volume 52,Page 655, 1991.

[13] H. B. Gon, J. Cryst. Growth, Volume 102,Page 501,1990

[14] C. C. Desai and A. H. Patel, J. Mat. Sci. Lett, Volume 6, Page 1066, 1987.

[15] V. S. Yadava and V. M. Padmanabhan, Acta. Cryst, B Volume 29,Page 493, 1973.

[16] L. V. Pipree and M. M. Kobklova, Radio Eng. Electron Phys, (USA),Volume 12,Page 33,1984.

[17] B. P. Nikam, S. J. Nandre,C.P.Nikam. JETIR ,Volume 9 (2) , 2022.1984.

Ravindra N More¹, Yuvraj M Bhosale²

^1,2PG Department of Zoology, NYNC ACS College, Chalisgaon, Jalgaon 424101 (MH)

Email ID- dryuvrajb0807@gmail.com

ABSTRACT

The red flour beetle, Tribolium castaneum (Herbst), is one of the most destructive cosmopolitan pests of stored grains and processed food products. Its remarkable adaptability, rapid life cycle, and increasing resistance to synthetic fumigants, such as phosphine, have intensified the search for safer and more sustainable alternatives. Botanical extracts, derived from plants rich in bioactive secondary metabolites, have shown promise as environmentally benign methods for controlling pests in stored products. This study offers a thorough, theoretical, and comparative synthesis of plant-derived chemicals, essential oils, and botanical extracts tested against T. castaneum until 2025. The modes of action, effectiveness comparisons, formulation advancements, possibilities for resistance management, and future research goals are highlighted.

To provide a cohesive framework for the logical development of plant-based pesticides for post-harvest protection, this review combines classical and modern literature.

KEYWORDS: Botanical insecticides, Essential oils, Tribolium castaneum, Phytochemicals, Sustainable pest management.

INTRODUCTION

Insects that infest stored products consistently endanger global food security, with Tribolium castaneum being one of the most economically important species because of its capacity to invade flour, cereals, and processed foods (Sokoloff 1974; Campbell and Arbogast 2004). Traditional control methods have relied significantly on chemical fumigants and long-lasting insecticides. Nonetheless, concerns about the environment, food safety problems, and the swift development of resistance, especially to phosphine, have diminished their lasting effectiveness (Coats, 1994; Nayak et al., 2020).

In this context, botanical extracts have received renewed scientific interest. Plants, which have been traditionally employed as grain protectants, possess a wide variety of secondary metabolites that are developed for their defense against herbivores (Fraenkel, 1959; Golob & Webley, 1980; Wink, 2012). Contemporary analytical methods and bioassays have facilitated a thorough assessment of these plants against T. castaneum, uncovering various insecticidal, repellent, antifeedant, and growth-regulating effects (Isman, 2006; Regnault-Roger et al., 2012).

MATERIAL AND METHODS-

• Biology and Pest Status of Tribolium castaneum

Understanding the biology of T. castaneum is fundamental for evaluating botanical control strategies. The beetle thrives in warm and dry storage conditions and completes multiple generations annually, leading to exponential population growth (Sokoloff, 1974). Both larvae and adult insects can cause quantitative and qualitative losses in food products. They contribute to contamination through the presence of frass (insect droppings), secretions, and allergens (Phillips and Throne, 2010).

Its physiological plasticity and detoxification enzyme systems contribute significantly to insecticide resistance during development (Campbell & Arbogast, 2004; Nayak et al., 2020). These characteristics make T. castaneum an ideal model organism for testing alternative pest control agents, including botanicals with multitarget modes of action.

• Rationale for Botanical Extracts in Stored-Product Protection

Botanical insecticides offer several advantages over synthetic chemicals, including biodegradability, reduced nontarget toxicity, and a lower risk of resistance development (Isman, 2008; Benelli et al., 2016). Plant-derived compounds often act on multiple physiological pathways, such as neuroreceptors, metabolic enzymes, and hormonal systems, making insect adaptation more difficult (Enan, 2001; Pavela, 2015).

Moreover, many botanicals are locally available and culturally accepted, aligning well with sustainable agriculture and integrated pest management (IPM) frameworks (Dubey et al., 2010; Dubey et al., 2011).

• Essential Oils as Fumigants and Contact Toxicants

Essential oils represent one of the most extensively studied botanical groups for the control of T. castaneum. Rich in monoterpenoids and phenylpropanoids, these volatile compounds exhibit strong fumigant toxicity, often comparable to synthetic fumigants in laboratory conditions (Lee et al., 2003; Chaubey, 2012).

Mechanistically, essential oils disrupt neural transmission by interacting with octopaminergic receptors and ion channels, leading to paralysis and death (Enan, 2001; Bakkali et al., 2008). Studies have demonstrated high mortality and repellency using oils from Artemisia, Thapsia, and other aromatic plants (Negahban et al., 2007; Salem et al., 2023; Zhang et al., 2024).

• Plant Powders and Crude Extracts

In addition to essential oils, crude plant powders and solvent extracts have demonstrated significant efficacy against T. castaneum. The leaf and seed powders of Aphanamixis polystachya reduced adult survival and progeny emergence in stored wheat, highlighting the practicality of low-technology applications (Ahmad et al., 2019).

Crude extracts often contain synergistic mixtures of alkaloids, flavonoids, terpenoids, and saponins, which collectively impair feeding, digestion, and reproduction (Harborne, 1998; Wink, 2012). Such complexity may enhance durability against the development of resistance.

• Saponins and Antinutritional Compounds

The capacity of saponin-rich extracts to damage membranes has drawn attention. Recent studies on Chenopodium quinoa have demonstrated notable insecticidal and antinutritional effects on T. castaneum, linked to midgut injury and digestive enzyme inhibition (El-Sheikh, 2025; Francis et al., 2002).

• Neem and Classical Botanical Insecticides

Neem (Azadirachta indica) is a benchmark botanical insecticide owing to its broad-spectrum activity and well-characterized mode of action (Schmutterer, 1990). Azadirachtin disrupts molting, reproduction, and feeding behavior in T. castaneum, making it particularly valuable for population suppression rather than rapid knockdown (Isman 2006).

• Nano Formulations and Technological Advances

Recent advances in nanotechnology have revitalized the research on botanical insecticides. Nanoencapsulation enhances stability, solubility, and controlled release of plant-derived compounds, addressing volatility and degradation issues (Kah et al., 2013).

Although still emerging, nano-formulated botanicals show promises for improving the consistency and scalability of plant-based control strategies against T. castaneum.

• Comparative Efficacy and Resistance Management

Comparative studies consistently show that while individual botanicals may vary in potency, their multi-site modes of action offer strategic advantages over single-target synthetic insecticides (Pavela & Benelli, 2016; Regnault-Roger et al., 2012).

Importantly, botanicals may play a critical role in resistance management by reducing the selection pressure when integrated with conventional methods (Nayak et al., 2020; Phillips & Throne, 2010).

• Environmental and Safety Considerations

Botanical insecticides are generally regarded as safer for non-target organisms and consumers, although rigorous toxicological evaluations remain essential (Coats, 1994; Isman, 2020). Their rapid degradation minimizes environmental persistence, which aligns with sustainability goals.

• Challenges and Future Perspectives

Despite encouraging laboratory findings, challenges such as field validation, standardization, and regulatory acceptance persist (Isman & Grieneisen, 2014; Benelli et al., 2016). Future studies should emphasize formulation science, synergistic mixtures, and practical storage conditions.

CONCLUSION

Botanical extracts are a scientifically valid and eco-friendly option for controlling Tribolium castaneum. Utilizing both conventional wisdom and contemporary studies, these plant-derived solutions provide multifunctional roles, minimize the risk of resistance, and align with sustainable pest control systems. Ongoing interdisciplinary studies are crucial for converting their potential into functional and scalable applications.

Table: Representative botanical extracts evaluated against Tribolium castaneum.

Azadirachta indica (Neem)	Seeds	Azadirachtin extract	Growth inhibition, reduced fecundity	Ecdysone disruption	Schmutterer (1990); Isman (2006)
Artemisia sieberi (D. Wormwood)	Aerial parts	Essential oil	High fumigant mortality	Neurotoxicity	Negahban et al.(2007)
Thapsia garganica (D. Carrots)	Seeds	Essential oil	Strong contact & fumigant toxicity	AChE inhibition	Salem et al.(2023)
Chenopodium quinoa (Rajgira)	Seeds	Saponin-rich extract	Digestive inhibition	Membrane disruption	El-Sheikh (2025)
Aphanamixis polystachya (Pithraj Tree)	Leaves & seeds	Powder	Reduced progeny	Antifeedant	Ahmad et al.(2019)

GRAPHICAL ABSTRACT

Plant-derived resources → Extraction (powders, crude extracts, essential oils, nano formulations) → Bioactive phytochemicals (terpenoids, alkaloids, saponins, phenolics) → Multiple physiological targets (nervous system, digestion, reproduction) → Mortality, repellency, population suppression of Tribolium castaneum → Sustainable and residue-safe stored-product protection.

REFERENCES

1. Abou-Taleb, H. K., El-Sheikh, T. M., & Abdel-Rahman, H. A. (2021). Fumigant toxicity and biochemical effects of selected essential oils   on   the red flour beetle, Tribolium castaneum (Coleoptera: Tenebrionidae).   Journal of Stored   Product   Research, 93, 101825. 
2. Ahmad, S., Khan, R. R., & Hasan, M. (2019). Insecticidal efficacy of   pithraj (Aphanamixis   polystachya) leaf and seed powders against   Tribolium castaneum   in stored wheat.   Journal of Basic and Applied Zoology, 80(1), 1–10. 
3. Bakkali, F., Averbeck, S., Averbeck, D., &   Idaomar, M. (2008). Biological effects of essential oils: A review.   Food and Chemical Toxicology, 46(2), 446–475. 
4. Benelli, G., Pavela, R., Canale, A., Mehlhorn, H., & Murugan, K. (2016). Essential oils as eco-friendly biopesticides Challenges and constraints.   Trends in Plant Science, 21(12), 1000–1007. 
5. Campbell, J. F., & Arbogast, R. T. (2004). Stored-product insects in changing   climates.   Annual Review of Entomology   49, 351–377. 
6. Chaubey, M. K. (2012). Biological effects of essential oils   on   stored-product insects.   Journal of Biopesticides, 5(1), 1–10. 
7. Coats, J. R. (1994). Risks   of   natural versus synthetic insecticides.   Annual Review of Entomology, 39, 489–515. 
8. Dubey, N. K., Shukla, R., Kumar, A., Singh, P., & Prakash, B. (2010). Global scenario on the application of natural products in integrated pest management   programs.   Journal of Natural Products, 3, 1–18. 
9. Dubey, N. K., Shukla, R., Kumar, A., Singh, P., & Prakash, B. (2011). Prospects of botanical pesticides in sustainable agriculture.   Current Science, 100(4), 479–488. 
10. El-Sheikh, T. M. Y. (2025). Antinutritional and insecticidal potential of saponin-rich extract of   Chenopodium quinoa   against   Tribolium castaneum   and its   mechanism of action     Scientific Reports, 15, 10952. 
11. Enan, E. (2001). Insecticidal activity of essential oils: Octopaminergic sites of action.   Pesticide Biochemistry and Physiology   69(1):   15–22. 
12. Fraenkel, G. S. (1959). The raison d’être of secondary plant substances.   Science, 129(3361), 1466–1470. 
13. Francis, G., Kerem, Z., Makkar, H. P. S., & Becker, K. (2002).   Biological     actions   of saponins in animal systems: A review.   British Journal of Nutrition, 88(6), 587–605. 
14. Golob, P., & Webley, D. J. (1980).   The use of plants and minerals as traditional protectants of stored products   is common. Tropical Products Institute, UK. 
15. Harborne, J. B. (1998).   Phytochemical methods: A guide to modern techniques of plant analysis (3rd ed.). Springer. 
16. Isman, M. B. (2006). Botanical insecticides, deterrents and repellents in modern agriculture.   Annual Review of Entomology, 51, 45–66. 
17. Isman, M. B. (2008). Botanical insecticides: For richer   or   poorer.   Pest   Manag     Sci, 64(1), 8–11. 
18. Isman, M. B. (2020). Botanical insecticides in the twenty-first century:   Fulfilling their promise?   Annual Review of Entomology, 65, 233–249. 
19. Isman, M. B., &   Grieneisen, M. L. (2014). Botanical insecticide research: Many publications, limited useful data.   Trends in Plant Science, 19(3), 140–145. 
20. Kah, M., Beulke, S., Tiede, K., & Hofmann, T. (2013).   Nanopesticides: State of knowledge, environmental fate, and exposure modeling.   Critical Reviews in Environmental Science and Technology, 43(16), 1823–1867. 
21. Lee, S., Peterson, C. J., & Coats, J. R. (2003). Fumigation toxicity of monoterpenoids to several   stored-product   insects.   Journal of Stored Products Research, 39(1), 77–85. 
22. Negahban, M.,   Moharramipour, S., &   Sefidkon, F. (2007). Fumigant toxicity of essential oil from   Artemisia   sieberi   against stored-product insects.   Journal of Stored Products Research, 43(2), 123–128. 
23. Nayak, M. K. Collins, P. J., Pavic, H.,   and   Kopittke, R. A. (2020). Resistance to phosphine in stored-product insects: Current status and future prospects.   Journal of Stored   Product   Research, 86, 101555. 
24. Papachristos, D. P., &   Stamopoulos, D. C. (2002). Repellent, toxic, and reproduction-inhibitory effects of essential oils on stored-product insects.   Journal of Stored Products Research, 38(2), 117–128. 
25. Pavela, R. (2015). Acute toxicity and synergistic effects of some monoterpenoid essential oil compounds on   Tribolium castaneum.   Journal of Pest Science, 88(4), 747–754. 
26. Pavela, R., & Benelli, G. (2016). Essential oils as eco-friendly biopesticides Challenges and constraints:     Industrial Crops and Products, 76, 174–187. 
27. Phillips, T. W., & Throne, J. E. (2010). Biorational approaches to managing stored-product insects.   Annual Review of Entomology, 55, 375–397. 
28. Rajendran, S., &   Sriranjini, V. (2008). Plant products as fumigants for stored-product insect control.   Journal of Stored Products Research, 44(2), 126–135. 
29. Regnault-Roger, C., Vincent, C., & Arnason, J. T. (2012). Essential oils in insect control: Low-risk products in a high-stakes world.   Annual Review of Entomology, 57, 405–424. 
30. Salem, N.,   Bachrouch, O.,   Sriti, J., & Hammami, M. (2023). Chemical composition and insecticidal activity of   Thapsia     garganica   seed essential oil against   Tribolium castaneum.   Pest Management Science, 79(4), 1562–1571. 
31. Schmutterer, H. (1990). Properties and potential of natural pesticides from the neem tree.   Annual Review of Entomology, 35, 271–297. 
32. Sokoloff, A. (1974).   The biology of Tribolium. Oxford University Press. 
33. Tripathi, A. K., Upadhyay, S., Bhuiyan, M., & Bhattacharya, P. R. (2009). A review on prospects of essential oils as biopesticides.   Current Science, 86(6), 787–794. 
34. Wink, M. (2012). Plant secondary metabolites as defenses against herbivores.   Annual Plant Reviews, 39, 121–145. 
35. Zhang, X., Wang, Y., & Liu, Z. (2024). Chemical profiling and insecticidal activity of commercial essential oils against   Tribolium castaneum. Industrial Crops and Products, 210, 118034. 

Raju N. Devkar ¹ and Dr. Vishal N. Shinde ²

1. Assistant Professor in Botany, VVM’s S.G. Patil ASC College Sakri Tal. Sakri Dist. Dhule-424304 (MS) India.

Mail ID – rajudevkar094@gmail.com

• Associate Professor in Botany, ADMSP’s Late Annasaheb R D Deore Art’s and Science College, Mhasadi Tal.Sakri, Dist. Dhule- 424304 (MS) India

Mail ID – vishalshinde1001@gmail.com

ABSTRACT: Free radicals are continuously generated in the body during normal metabolic processes and though exposure to environmental factors such as infectious agents, pollution, UV light and radiations. When these harmful free radicals are not neutralized by primary and secondary defence mechanism of body, oxidative stress occurs, which is the reasons for development of various diseases. Plants have many phytoconstituents including saponin, flavonoids and polyphenol with high antioxidants properties. To determination of antioxidant properties of Tribulus spp. extracts (methanol and aqueous) DPPH (1,1- diphenyl 2- picryl hydrazyl) method was used. Whereas DPPH free radical scavenging activity of methanol extracts revealed the strongest as compared to aqueous extracts.

KEYWORDS: Antioxidants, DPPH, Phenolic compounds, Flavonoids, Tribulus rajasthanensis L.

INTRODUCTION:

          Since ancient times, the medicinal properties of plants have been investigated in the recent scientific developments throughout the world, due to their potent antioxidant activities. As antioxidants have been reported to prevent oxidative damage caused by free radicals, it can interfere with the oxidation process by reacting with free radicals, cheating, catalytic metals and also acting as oxygen scavengers ^[1]. Reactive oxygen species (ROS), such as hydrogen peroxide (H₂O₂) and hypochlorous acid (HOCl), and free radicals, such as the superoxide anion (O₂^–) and hydroxyl radical (OH), are produced as normal products of cellular metabolism. Overproduction of free radicals and ROS can lead to oxidative damage to various biomolecules including proteins, lipids, lipoproteins and DNA. This oxidative damage is a critical etiological factor implicated in several chronic disorders such as Cancer, Mellitus, diabetes, inflammatory disease, asthma, cardiovascular disease, neurodegenerative disease and premature aging ^[2,3]. Antioxidants are means for the substances or group of substances that inhibit oxidative damage to a molecule. This defense system is having many modes of classification such as based on their metabolism of action (chain breaking, preventive). Many plants contain large amounts of antioxidants such as vitamin C, vitamin E, lycopene, lutein, carotenoids, polyphenols which play important roles in adsorbing and neutralizing free radicals ^[4]. Beside this, phenolic compounds and flavonoids which have been reported to exert multiple biological effects, including free radical scavenging abilities, anti-inflammatory, anticarcinogenic etc. ^[5].

          Whereas unfavorable environmental conditions for plants, including extreme temperatures, drought, heavy metal exposure, nutrient deficiencies, and high salinity, lead to the excessive production of reactive oxygen species (ROS), which can induce oxidative stress. To counteract this damage, plant cells possess an antioxidant defense system composed of both enzymatic and non-enzymatic components. Non-enzymatic antioxidants act through various mechanisms, such as enzyme inhibition, chelation of trace elements involved in free radical generation, scavenging and neutralization of reactive species, and enhancement of protection via interaction with other antioxidant systems. Among these compounds, secondary metabolites particularly phenolic compounds play a crucial role in protecting plants against oxidative stress ^[6].

          Tribulus rajasthanensis L. belongs to the family zygophyllaceae. It is an annual plant with a wide global distribution and is commonly found throughout India. The species primarily grows wild in dry and arid regions, especially in West Rajasthan, Gujarat, Maharashtra, Uttar Pradesh, and other similar areas ^{[7, 8, 9]}.

          The plant is a decumbent herb with pinnately compound leaves. The leaves typically bear 3–10 pairs of sessile leaflets with unequal, oblique, or rounded bases. Flowers are solitary and pentamerous. The number of stamens ranges from five to ten, and the ovary is five-chambered. The fruit is the most characteristic feature of this genus. At maturity, it divides into five indehiscent mericarps, each containing two to five seeds arranged in a horizontal row.

          According to Bhandari and Sharma (1977), the species is closely allied to T. terrestris L. but can be easily distinguished by its secondary spines and the complete absence of lower pair of spines. Typical specimens with mature mericarp can be easily told apart while the intermediate forms that show the characters of both Tribulus rajasthanensis and Tribulus terrestris are difficult to separate. The typical forms of T. rajasthanensis as a variety of T. terrestris ^[10]. The aim of the present study was to evaluate the antioxidant activity of Tribulus rajasthanensis L. extracts by DPPH methods.

MATERIALS AND METHODS:

Plant materials: The healthy infection free mature plants parts (Fruits, stem, leaves and roots) were collected from the Gomai bank of river, Shahada taluka, Nandurbar District and then they were shade dried and powdered separately in laboratory and kept safely for further research.

Preparation of crude extracts in water: 10 g of dry plant powder was taken in a beaker, 100 ml of distilled water was added, and the mixture was stirred by a magnetic stirrer for 24 h. After that it is filtered by Whatman’s filter paper No.1 and filtrate were centrifuged at 3000 rpm for 15 min. The supernatant was evaporated by rotary evaporator, to get dried form. It was weighed and kept in a refrigerator in sterilized and dark glass containers ^[11].

Preparation of crude extracts in methanol: Solvent extracts were prepared in methanol at room temperature. 10g of dry plant powder was mixed in sufficient quantity of methanol in conical flask. The conical flasks were plugged tightly with cork. Shaken the conical flask properly to mix the content then kept the conical flask for about 30 minutes for the extraction. After 30 minutes it was filtered and filtrate were collected in china dish. These dishes kept on a water bath for some time to evaporate the solvent, after that the methanolic extract were completely dried.

 Antioxidant Activity (DPPH free radical scavenging activity):

          Free radical scavenging activity was determined using the stable 1,1- diphenyl -2-picryl hydrazyl radical (DPPH) according to the method described by Shimada et al. (1992). Butylated hydroxytoluene (BHT) were used as standard control. Various concentrations of the extracts were added to 4 ml of a 0.004% methanol solution of DPPH. The mixture was shaken and left for 30 minutes at room temperature (25 ± 5⁰C) in the dark, and the absorbance was then measured with a spectrophotometer at 517 nm. All determinations were performed in triplicate ^[12,13,14]. antioxidant activity was calculated as the percent inhibition caused by the hydrogen donor activity of each sample according to the following:

Inhibition (%) = [(Absorbance _control – Absorbance _sample)/ (Absorbance _control) ×100

Where: absorbance control is the absorbance of DPPH radical plus methanol; absorbance sample is the absorbance of DPPH radical plus sample extract or standard.

RESULTS:

           Many plants exhibits in vitro and in vivo antioxidant properties owing to their phenolics, vitamins, proteins and pectins contents. In the different literatures, it has been revealed that the antioxidant activity of plant extracts is responsible for their therapeutic effect against cancer and many more disorders. Hence, Tribulus rajasthanensis L. plant extracts were evaluated for in vitro antioxidant activities. DPPH (1,1-diphenyl, 2- picryl hydrazyl) method were used for evaluation of in vitro antioxidant activity.

                  In the present study several biochemical constituents and free radical scavenging activity of Tribulus were evaluated. Free radicals are involved in many disorders like neurodegenerative diseases and cancers. Scavenging activity of antioxidants are useful for the control of these diseases. DPPH stable free radical method is a sensitive method to evaluate the antioxidant activity of plant extracts. DPPH radical scavenging activity of methanolic extracts of Tribulus showed strongest while some parts of plants revealed moderate antioxidant properties in aqueous extracts.

DISCUSSION:

           medicinal plants have been used to treat a wide range of disorders since ancient times. From simple cold to complex diseases these plants have served as effective therapeutic agents ^[15]. Tribulus rajasthanensis L. as a well- known medicinal plant, was selected for this study primarily because of it’s antioxidants potential. Plant extracts were evaluated for in vitro antioxidant activities. DPPH Method provides a good assessment for evaluation of in vitro antioxidant activity. It is based on reaction between antioxidant with nitrogen centered free radical i. e. DPPH (1,1 diphenyl, 2- picryl hydrazyl). That’s why in this experiment; we evaluated the in vitro antioxidant and radical scavenging activities of Tribulus spp. methanol extract using DPPH Method.

           Oxidative stress is a deep-rooted cause of various disorders, including rheumatoid, arthritis and inflammation, neurodegenerative disease, diabetes, cancer, aging etc. Preventing the production of reactive oxygen species (ROS) and reactive nitrogen species (RNS) during cellular metabolism is critically important. The widespread use of medicinal plants across different therapeutic contexts encouraged us to investigate Tribulus spp. to assess its antioxidant and free radical scavenging properties. Our result revealed the tremendous potential of this plant in reducing free radical through DPPH, possibly due to its high polyphenol content. However, more investigations should be carried out to clarify the specific correlations between the plant bioactive and the observed biological activities.

References:

1. Patel V. R., et al. (2010); Antioxidant activity of some selected medicinal plants in Western region of India. Advances in biological research, 4(1): 23-26.
2. Ghimire B. K., et al. (2011); A comparative evaluation of the antioxidant activity of some medicinal plants popularly used in Nepal. Journal of medicinal plants research,5(10): 1884-1891.
3. Patel V. R., et al. (2010); Antioxidant activity of some selected medicinal plants in Western region of India. Advances in biological research, 4(1): 23-26.
4. Agrawal S. S., et al. (2008); Antioxidant activity of fractions from Tridax procumbens. Journal of Pharmacy research, 2: 71-73.
5. Patel V. R., et al. (2010); Antioxidant activity of some selected medicinal plants in Western region of India. Advances in biological research, 4(1): 23-26.
6. Chaves N., et al. (2020); Quantification of the antioxidant activity of plant extracts: Analysis of sensitivity and Hierarchization Based on the method used. MDPI,9(76): 1-15.
7. Lokhande K. D., et al. (2014); Evaluation of antioxidant potential of Indian wild leafy vegetable Tibullus terrestris. Int J Adv Pharma Biol Chem., 3: 2277- 4688.
8. Hussain A. A., et al. (2009); study the biological activities of Tribulus terrestris extracts. World Acad Sci Eng Technol., 57: 433-435.
9. Mohammed M. J. (2008); biological activity of saponins isolated from Tribulus terrestris (fruit) on growth of some bacteria. Tikrit Journal of Pure Science, 13(3): 17-20.
10. Varghese M., et al. (2006); Taxonomic status of some of the Tribulus species in the Indian subcontinent. Saudi journal of biological sciences, 13(1):7-12.
11. Abdulqawi L.N. and Syed A.Q. (2021); Evaluation of Antibacterial and Antioxidant activities of Tribulus terrestris L. Fruits. Research J. Pharm. and Tech.,14(1):331-336.
12. Ghimire B. K., et al. (2011); A comparative evaluation of the antioxidant activity of some medicinal plants popularly used in Nepal. Journal of medicinal plants research,5(10): 1884-1891.
13. Javed S. R., et al. (2018); In vitro and in Vivo assessment of free radical scavenging and antioxidant activities of Veronica persica Poir. Cellular molecular biology, 57-64.
14. Patel V. R., et al. (2010); Antioxidant activity of some selected medicinal plants in Western region of India. Advances in biological research, 4(1): 23-26.
15. Javed S. R., et al. (2018); In vitro and in Vivo assessment of free radical scavenging and antioxidant activities of Veronica persica Poir. Cellular molecular biology, 57-64.

Rahul Patil^1*, Sunil Sajgane¹, Suraj Vasave¹, Sandip Patil²

¹ Y.C.S.P. Mandal’s Dadasaheb Digambar Shankar Patil Arts, Commerce and Science College, Erandol 425109, Maharashtra, India.    

² N.T.V.S’s G. T. Patil Arts, Commerce and Science College, Nandurbar 425412, Maharashtra, India.

Corresponding Author Email Id: rahul92ppatil@gmail.com

———————————————————————————————————————

Abstract:

Self-healing materials have garnered significant interest for their ability to autonomously repair damage, improve reliability, and extend the service life of polymer systems. Among various strategies, micro- and nano-encapsulation of healing agents combined with polymeric coatings has emerged as an effective approach, enabling controlled release, protection of active agents, and enhanced mechanical performance. This review highlights recent advances in encapsulation techniques, including physical, chemical, and physico-chemical methods, and examines the influence of capsule size, shell thickness, and morphology on healing efficiency. The selection of polymer coatings thermoset, thermoplastic, and stimuli-responsive is discussed in relation to mechanical reinforcement, environmental resistance, and triggerable release mechanisms. Key self-healing mechanisms, such as capsule rupture, diffusion-based repair, and multi-cycle healing, are summarized. Current challenges, including material compatibility, environmental concerns, cost, and scalability, are addressed, along with future perspectives on sustainable materials, multi-functional coatings, and smart self-healing systems for applications in composites, coatings, electronics, and biomedical devices.

Graphical Abstract:

Keywords: Encapsulation, Self-Healing Coating, Thermoset, Thermoplastic

1. Introduction:

The growing demand for durable, reliable, and sustainable materials has driven extensive research into self-healing polymer systems capable of autonomously repairing damage and restoring functionality [1,2]. Microcracks generated during service are often precursors to catastrophic failure in polymeric materials and composites, particularly in structural, coating, and electronic applications [3]. Conventional repair strategies are typically labor-intensive, costly, and impractical for inaccessible or microscale damage, motivating the development of materials with intrinsic or extrinsic self-healing capabilities. Among the various self-healing approaches, the encapsulation of healing agents within micro- or nano-sized containers represents one of the most widely investigated and practically viable strategies [2,4]. In encapsulation-based self-healing systems, liquid or solid healing agents are stored within discrete capsules embedded in a polymer matrix. Upon crack initiation and propagation, these capsules rupture or activate, releasing the healing agent into the damaged region where it undergoes polymerization, crosslinking, or physical consolidation, thereby sealing the crack and partially or fully restoring mechanical integrity [5,6].

Micro‑ and nano‑encapsulation offers several advantages over other self‑healing strategies, including effective protection of sensitive healing agents, controlled release behavior, and compatibility with a broad range of polymer matrices [5]. Capsule size plays a critical role in determining healing efficiency, dispersion uniformity, and mechanical performance of the host material. While microcapsules are effective for delivering sufficient quantities of healing agents, nanocapsules provide improved dispersion, reduced stress concentration, and the potential for multiple healing events [7]. Polymer coating or shell materials are a key component of encapsulation‑based self‑healing systems, as they govern capsule stability, mechanical strength, interfacial adhesion, and rupture behavior [2,8]. Commonly employed polymer shells include urea–formaldehyde, melamine–formaldehyde, polyurethane, polyurea, and hybrid shells decorated with inorganic nanolayers for enhanced stability [9]. Recent research has increasingly focused on tailoring polymer coatings through chemical modification or the use of stimuli-responsive polymers to enhance healing efficiency and durability under complex service conditions [8,9]. Despite significant progress, several challenges remain in the large-scale implementation of polymer-coated micro/nano-encapsulation systems, including synthesis scalability, capsule–matrix compatibility, long-term stability, and environmental concerns associated with certain shell materials [2,10]. Therefore, a comprehensive understanding of encapsulation synthesis methods, polymer coating strategies, and their influence on self-healing performance is essential.

This review aims to summarize and critically discuss recent advances in micro- and nano-encapsulation techniques and polymer coating materials used for self-healing applications. Emphasis is placed on synthesis methodologies, structure-property relationships, and practical applications in polymer composites and coatings, while highlighting current limitations and future research directions.

2. Micro/Nano Encapsulation Techniques

Micro- and nano-encapsulation techniques employed for self-healing applications are generally classified into physical, chemical, and physico-chemical methods based on the mechanism of capsule formation. The choice of encapsulation technique significantly influences capsule size, shell morphology, mechanical robustness, and release behavior of the healing agent, thereby affecting overall self-healing efficiency [11,12].

2.1 Physical Methods

Physical encapsulation methods rely primarily on mechanical or thermodynamic processes without involving chemical reactions for shell formation. Common techniques include spray drying, solvent evaporation, phase separation, and melt dispersion [13]. In spray drying, a solution or emulsion containing the healing agent and shell material is atomized into a heated chamber, leading to rapid solvent evaporation and capsule formation. This method is attractive due to its simplicity, scalability, and industrial compatibility; however, it often produces capsules with relatively broad size distributions and limited control over shell thickness [14].

Solvent evaporation and phase separation techniques are widely used for encapsulating liquid healing agents within polymer shells. In these methods, an oil-in-water or water-in-oil emulsion is prepared, followed by controlled solvent removal to induce polymer precipitation around the core material. Although physical methods are cost-effective and easy to implement, the resulting capsules may exhibit lower mechanical strength and reduced stability under long-term service conditions compared to chemically synthesized shells [13].

2.2 Chemical Methods

Chemical encapsulation methods rely on in situ chemical reactions to form polymeric shells around healing agent cores, offering excellent control over capsule size, shell thickness, and mechanical properties, which makes them widely used in self-healing polymer systems [15]. Common approaches include in situ polymerization, interfacial polymerization, and emulsion polymerization. Urea–formaldehyde (UF) and melamine–formaldehyde capsules formed via in situ polymerization exhibit high mechanical strength, thermal stability, and effective rupture during crack propagation [16]. Interfacial polymerization enables the formation of robust polyurethane, polyurea, and polyamide shells, while emulsion polymerization is often employed to produce PMMA shells with uniform morphology. Although chemical methods allow precise tuning of capsule characteristics, the use of toxic monomers and complex reaction conditions raises environmental and safety concerns [15,17].   

Figure 1: Schematic representation of chemical encapsulation methods showing polymeric shell formation around core materials [15,16].

2.3 Physico-Chemical Methods

Physico-chemical encapsulation methods combine elements of both physical and chemical processes to form capsules with tailored properties. Coacervation, sol–gel techniques, and layer-by-layer (LbL) assembly are prominent examples [11,18]. Complex coacervation, based on electrostatic interactions between oppositely charged polymers, enables the formation of capsules with high encapsulation efficiency and relatively uniform size distribution. This method is particularly suitable for temperature-sensitive healing agents.

Sol–gel encapsulation involves the hydrolysis and condensation of inorganic precursors to form hybrid organic–inorganic shells, offering enhanced thermal and chemical stability. Layer-by-layer assembly allows precise control over shell thickness and functionality through sequential deposition of polymeric or inorganic layers, making it attractive for stimuli-responsive and multi-functional self-healing systems. Despite their versatility, physico-chemical methods may face challenges related to processing complexity and scalability [18].

• Polymer Coating Materials and Strategies

Polymer coatings are widely applied in protective, functional, and controlled-release systems. Selection of coating material and strategy depends on mechanical properties, thermal behavior, and responsiveness to stimuli. Major polymer classes used are thermoset polymers, thermoplastic polymers, and stimuli-responsive polymers.

3.1 Thermoset Polymers

Thermoset polymers are crosslinked materials that form rigid, insoluble, and heat-resistant structures upon curing. The crosslinking process creates a three-dimensional network that imparts excellent mechanical strength, chemical stability, and dimensional integrity. Common examples of thermosets include epoxy resins, polyurethane, and phenolic resins. Due to their robust properties, thermoset polymers are widely employed in protective coatings, corrosion-resistant layers, electrical insulation, adhesives, and even self-healing systems. Their inherent rigidity and resistance to deformation make them ideal for applications where durability under mechanical or chemical stress is critical. However, the irreversible crosslinking reaction also limits their reprocessability; once cured, thermosets cannot be remelted, reshaped, or recycled like thermoplastics. This characteristic necessitates careful processing and design considerations during manufacturing to ensure optimal performance. Advances in thermoset chemistry, including the development of reprocessable or partially reversible networks, are emerging to address these limitations [19].

3.2 Thermoplastic Polymers

In contrast, thermoplastic polymers are linear or slightly branched materials that soften upon heating and solidify when cooled, making them highly processable and recyclable. Common thermoplastics used in coatings include polyethylene (PE), polypropylene (PP), poly(methyl methacrylate) (PMMA), and polyvinyl alcohol (PVA). Their reversible thermal behavior allows for reshaping, extrusion, and molding into complex geometries. Thermoplastic coatings offer advantages such as flexibility, ease of fabrication, and potential for material recovery at the end of life. However, they generally exhibit lower chemical, thermal, and mechanical resistance compared to thermosets, limiting their use in highly demanding environments. Innovations in thermoplastic blends, composites, and nanofiller incorporation aim to improve their performance, particularly for protective and functional coatings [20].  

3.3 Stimuli-Responsive Polymers

Stimuli-responsive or “smart” polymers are materials that undergo reversible changes in their physical or chemical properties in response to external stimuli such as temperature, pH, light, or magnetic fields. For example, poly(N-isopropylacrylamide) (PNIPAM) exhibits thermo-responsive behavior, contracting or swelling with temperature variations, while chitosan and alginate derivatives respond to pH changes for controlled release applications. These polymers are particularly valuable for advanced coating systems, drug delivery platforms, and adaptive surfaces, where dynamic responses to environmental changes are required. By tuning the polymer composition and architecture, it is possible to achieve precise control over release rates, adhesion, permeability, and other functional properties, opening new avenues for smart material design and multifunctional coatings [21].

• Self-Healing Mechanisms Enabled by Encapsulation

Encapsulation-based self-healing strategies improve the autonomous repair of materials by storing healing agents within micro- or nano-capsules, which are released upon damage. The primary mechanisms include capsule rupture-based healing, diffusion-based healing, and multiple healing cycles.

4.1 Capsule Rupture-Based Healing

Capsule rupture-based self-healing relies on microcapsules embedded within a polymer matrix that release healing agents upon mechanical damage. When a crack propagates through the material, it ruptures the microcapsules, releasing the encapsulated agent into the damaged region. This healing agent subsequently reacts, often in the presence of a catalyst dispersed within the matrix, to polymerize and seal the crack. Commonly used systems include urea-formaldehyde or melamine-formaldehyde microcapsules filled with epoxy, polyurethane, or other reactive monomers. The primary advantage of capsule rupture mechanisms is the rapid, localized repair they provide, which can restore mechanical integrity soon after damage occurs. However, this approach is inherently single-use, as the microcapsules are consumed during the healing event. Once a capsule is depleted, the same site cannot be healed again, limiting the material’s long-term self-healing capability. Researchers have explored methods to improve capsule efficiency and optimize agent loading, ensuring that cracks encounter sufficient healing material to restore strength and prevent crack propagation [22].

4.2 Diffusion-Based Healing

Diffusion-based self-healing strategies rely on the controlled migration of healing agents from internal reservoirs, such as vascular networks, hollow fibers, or nanocapsules, into damaged regions over time. Unlike rupture-based systems, which act only at the moment of mechanical failure, diffusion mechanisms allow continuous, gradual repair and can address more extensive or distributed damage. Healing agents move through the matrix either passively, driven by concentration gradients, or actively in response to external triggers. Integration with stimuli-responsive polymers enhances this approach; for example, changes in temperature, pH, moisture, or light can accelerate or direct the diffusion process. This controlled delivery ensures that healing occurs precisely where and when it is needed, improving durability and extending the operational lifetime of the material [23].

• Multiple Healing Cycles

Single-use capsule systems are limited by their inability to repair recurrent damage. To address this, multi-capsule arrangements or interconnected microvascular networks have been developed, providing fresh healing agents for repeated healing events. In such systems, cracks can access new reservoirs, enabling multiple repair cycles and significantly prolonging the service life of the polymer. Advanced designs combine capsule and vascular strategies or exploit reversible chemistries, such as Diels–Alder reactions or supramolecular bonding, which allow healing agents to re-form after reaction. These multi-cycle systems are particularly advantageous for high-stress environments or structural applications, where damage may occur repeatedly over time. By integrating both material design and delivery architecture, researchers have created self-healing polymers capable of responding to diverse damage scenarios, making them more practical for industrial and commercial applications [24].

4.4 Comparative Overview of Self-Healing Strategies

Each self-healing approach offers unique advantages and limitations depending on the application. Capsule rupture-based systems provide fast, localized repair and are relatively simple to implement, but their single-use nature restricts long-term effectiveness. Diffusion-based mechanisms, in contrast, allow continuous or delayed healing over larger areas and can be finely tuned using stimuli-responsive polymers; however, their repair rate may be slower, and precise control over agent migration may be challenging [25]. Multi-cycle healing systems address the limitations of single-use capsules by providing repeated access to fresh healing agents, either through microvascular networks or reversible chemistries, enhancing durability and structural longevity. By carefully selecting and combining these strategies, materials can be engineered for specific operational requirements-for instance, rapid localized repair for low-damage risk environments, sustained healing for slow-degrading materials, or multiple-cycle systems for critical load-bearing applications. The ongoing development of hybrid approaches, such as integrating capsule rupture with vascular delivery or embedding smart stimuli-responsive agents, offers the potential to achieve both immediate and long-term self-healing performance, making polymers more reliable and resilient for industrial, aerospace, and biomedical applications [26].

• Applications in Polymer Composites

Structural Materials:

Diffusion-based self-healing is particularly valuable in structural polymer composites, where the formation of microcracks over time can severely compromise mechanical integrity and lead to premature failure. Unlike single-use capsule systems, diffusion-based mechanisms allow healing agents to gradually migrate into damaged regions, enabling continuous or repeated repair even in areas that are difficult to access. This property is especially important in aerospace, automotive, and civil engineering applications, where components are subject to cyclic loading, environmental degradation, and complex stress distributions. By maintaining the integrity of the polymer matrix, diffusion-based healing reduces the risk of crack coalescence and catastrophic failure, effectively extending the service life of high-performance materials. Advanced designs often integrate stimuli-responsive polymers, where temperature, moisture, or mechanical stress can trigger or accelerate the diffusion of healing agents, ensuring timely repair. Additionally, diffusion-based systems can be combined with fiber-reinforced composites or microvascular networks to optimize the distribution of healing agents throughout large, load-bearing structures, providing both durability and resilience in demanding operational environments [27].

Coatings:

In protective coatings, self-healing polymers play a critical role in restoring barrier properties against environmental degradation, chemical attack, corrosion, or mechanical wear. Diffusion-based mechanisms are particularly advantageous in this context, as they allow healing agents to gradually migrate into damaged or scratched regions without requiring external intervention, maintaining the continuity and integrity of the coating. This ensures that the underlying substrate remains shielded from moisture, oxygen, or corrosive agents, which is especially important in metal structures, pipelines, and marine equipment. Stimuli-responsive coatings further enhance performance by activating healing processes in response to environmental triggers such as changes in moisture, pH, temperature, or even UV exposure. For instance, pH-sensitive coatings can release corrosion inhibitors when exposed to acidic conditions, while moisture-responsive systems can accelerate polymerization to seal microcracks. Incorporating nanocapsules or microvascular networks into these coatings can improve the distribution and availability of healing agents, allowing repeated or localized repairs and prolonging the operational life of protective surfaces in harsh industrial, marine, or infrastructure environments [28].

Electronics & Smart Materials:

Self-healing polymer composites are increasingly being adopted in flexible electronics, wearable devices, sensors, and other smart materials, where mechanical integrity and consistent performance are critical. Diffusion-based healing mechanisms play a key role in these applications by allowing healing agents to migrate into microcracks or damaged regions, restoring both the structural and functional properties of the material without external intervention. This ensures that minor mechanical damages—such as bending, stretching, or accidental scratches do not disrupt electrical pathways or compromise device functionality. When combined with stimuli-responsive polymers, the self-healing process can be precisely triggered by environmental or operational signals, such as temperature changes, light exposure, or electrical currents. Such targeted healing not only repairs physical damage but also preserves conductivity, sensor sensitivity, and overall device performance. Additionally, integrating nanocapsules, conductive fillers, or microvascular networks within the polymer matrix enhances the efficiency and speed of repair, supporting long-term reliability. These diffusion-enabled, smart self-healing systems are particularly important for next-generation electronics, soft robotics, and adaptive materials, where durability, resilience, and uninterrupted functionality are essential under repeated deformation or harsh operating conditions [29].

Figure 2: Applications of Self-Healing Micro/Nano Capsules in Structural Materials, Coatings, Electronics & Smart Materials.  

• Challenges and Future Perspectives

Despite significant advances in micro/nano encapsulation and self-healing polymer systems, several challenges remain that limit their widespread application. One major issue is the compatibility and stability of the encapsulated agents within the polymer matrix; Premature leakage, aggregation, or chemical degradation of the core material can reduce healing efficiency and long-term performance. Achieving uniform capsule size, shell thickness, and mechanical robustness, particularly at the nanoscale, also remains difficult, directly impacting reproducibility and release kinetics. Additionally, many chemical encapsulation processes rely on toxic monomers or organic solvents, raising environmental and safety concerns. The cost and scalability of producing high-quality micro/nano capsules and self-healing polymers is another limiting factor, preventing large-scale commercialization [30].

Future developments in the field are focused on addressing these limitations. The use of biodegradable polymers, water-based systems, and non-toxic monomers can reduce environmental impact while maintaining functional performance. Integration of stimuli-responsive polymers, multi-agent encapsulation, and nanoengineered shells offers potential for more precise controlled release, repeated healing cycles, and targeted delivery. Advances in fabrication techniques, including microfluidics, 3D printing, and layer-by-layer assembly, promise improved precision, reproducibility, and scalability. Finally, combining self-healing polymers with sensing technologies, electronics, or biomedical devices could enable the development of autonomous, adaptive, and multifunctional materials, paving the way for next-generation applications in a variety of industries.   

• Conclusion

Micro- and nano-encapsulation of healing agents, combined with tailored polymer coatings, represents a highly effective strategy for developing autonomous self-healing polymer systems. Physical, chemical, and physico-chemical encapsulation techniques allow precise control over capsule size, shell thickness, and release behavior, while thermoset, thermoplastic, and stimuli-responsive coatings enhance mechanical strength, environmental stability, and controlled activation of healing. Capsule rupture, diffusion-driven repair, and multi-cycle healing mechanisms demonstrate the versatility and practical applicability of these systems in polymers, composites, coatings, and biomedical materials. Despite significant progress, challenges such as material compatibility, environmental impact, scalability, and cost remain. Future research should focus on sustainable polymers, multi-functional coatings, and integration with smart and adaptive systems to achieve repeated healing, improved efficiency, and commercial viability. Overall, encapsulation-based self-healing strategies hold great promise for extending the service life and reliability of polymeric materials in diverse applications.

Acknowledgement: Rahul Patil sincerely acknowledges Kavayitri Bahinabai Chaudhari North Maharashtra University, Jalgaon, for awarding the Vice-Chancellor Research Motivation Scheme (VCRMS), which supported the research project.

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Dr. Sachin Ranu Govardhane

Dept of Geography

V.V. Ms S. G. Patil Arts, Science  And Commerce College Sakri,

Tal- Sakri Dist- Dhule.

Email Id sachingovardhane@gmail.com

Abstract

Forest ecosystems in the Satpuda fringe of North Maharashtra are very crucial in maintaining the ecological stability and tribal livelihoods, but they are becoming under pressure due to development pressures. The paper evaluates the change in forest cover and its sustainability development in the Satpuda fringe in 2015-2025 using a remote sensing and GIS-based methodology. Geometric, radiometric, and atmospheric corrections were applied to multi-temporal satellite images of Landsat 8 (2015) and Landsat 9/Sentinel-2 (2025). In ArcGIS Pro, supervised classification and post-classification change detection methods were used to measure the change of tehsil-wise forest cover in terms of area and percentage. The findings indicate a general and geographically imbalanced decrease in forest cover in the study area. The loss of forest was found to be significant in Akrani (247.90 sq. km; -19.14%) and Akkalkuwa (109.25 sq. km; -11.74%), which means that there is a strong pressure in tribal tehsils with a lot of forest. Other tehsils had moderate declines, with only Raver having a marginal growth (3.42 sq. km; +0.36%), probably because of local afforestation. Forest loss spatial distribution is in close relation to population increase, agricultural activities, and infrastructure. The paper identifies the urgency to have integrated land-use planning and conservation-based development policies to achieve long-term sustainability in the ecologically sensitive Satpuda fringe of North Maharashtra.

Keywords

Forest cover change; Remote sensing and GIS; Change detection; Sustainable development; Land use–land cover; Satpuda fringe, North Maharashtra.

Introduction

Forests are very important in ensuring an ecological balance, rural livelihoods and sustainable development, especially in socio-economically vulnerable and environmentally sensitive areas. In India, forested landscapes situated in hill ranges and tribal belts are becoming more and more strained with the increasing population, agricultural activities, development of infrastructure, and the shift in land-use patterns (Behera et al., 2015). The Satpuda Range, particularly its northern edge into North Maharashtra, including Nandurbar district, Dhule district and Jalgaon district is one such ecologically important area. This area is a transitional area whereby thick forest cover is slowly being replaced by agricultural land and human habitation and is therefore very vulnerable to forest degradation and loss (Zurqani et al., 2019).

The Satpuda fringe is typified by topography that is undulating, a forest cover that is mainly comprised of the deciduous forests and a tribal population that relies heavily on the forest cover to provide fuelwood, fodder, small forest produce and subsistence agriculture (Gautam et al., 2002). In the past 10 years, the traditional land-use patterns have changed due to developmental activities like road construction, agricultural intensification, expansion of settlements, and demographic growth (Giriraj et al., 2008). Although these changes are meant to enhance economic status and infrastructure, they tend to have unplanned ecological effects, especially the loss and degradation of forest cover (Bas et al., 2024). The loss of forests in such areas not only endangers the biodiversity and ecosystem services but also the very basis of sustainable development as it impacts the water availability, soil stability, and livelihood security (Kline et al., 2004).

The economic growth, social well-being, and environmental conservation must be balanced in a careful manner to achieve sustainable development in the forest-dependent regions (Mani & Varghese, 2018). Nevertheless, this balance is difficult to measure without credible and spatially explicit information on forest dynamics and association with development processes (Islomov et al., 2023). In this regard, remote sensing and GIS methods provide an effective and inexpensive method of tracking the change in forest cover over time (Stamatopoulos et al., 2024). The satellite-based analysis can be used to consistently monitor large and inaccessible regions and enable researchers to measure the loss of forests, spatial dynamics, and correlate them with socio-economic factors such as population growth and agricultural development at more specific administrative units like tehsils.

Although national level statistics on forests are available, localized research on current changes and development pressures at tehsil level is scarce in the case of the Satpuda fringe of North Maharashtra (Syamsih, 2024). In response to this gap, the current paper conducts a remote sensing-based evaluation of the change in forest cover between 2015 and 2025, a time when the area is experiencing a high rate of development. The study aims to combine satellite-based forest data with simple development indicators to gain a better insight into the spatial distribution of forest loss and its overlap with the ongoing development processes. The results should be relevant to the regional-level planning by identifying priority areas in which the development strategies should be more aligned with the forest conservation and long-term sustainability objectives.

Study Area

The study site is the Satpuda fringe of North Maharashtra, which is a region in the south foothills of Satpuda Range. It covers portions of Nandurbar district, Dhule district and Jalgaon district, and is a transitional region between forested hills and agricultural plains. The area is also marked by a topography of undulations, tropical dry deciduous forests and a majorly tribal population that relies on forest resources. Over the past years, population growth, agricultural activities, and development of infrastructure have escalated the pressure on forest areas and thus the Satpuda fringe is a vital area to understand the issues of forest loss and sustainable development.

Figure 3 LULC Map of Satpuda fringe of North Maharashtra during 2015–2025 to show change in forest cover.

Aim

The aim of the study is to assess forest loss and its implications for sustainable development in the Satpuda fringe of North Maharashtra by analyzing recent forest cover changes using remote sensing techniques and examining their relationship with selected development indicators.

Objectives

• To assess changes in forest cover in the Satpuda fringe of North Maharashtra between 2015 and 2025.
• To identify and analyze the spatial patterns of forest loss at the tehsil level within the study area.
• To examine the relationship between forest loss and development indicators, particularly population growth and agricultural expansion.
• To evaluate the implications of forest loss for sustainable development.

Methodology and Database

The current research uses a remote sensing and GIS-based approach to evaluate the change in forest cover and its effects on sustainable development in the Satpuda fringe of North Maharashtra. The decadal changes in the forest cover were analyzed using multi-temporal satellite data of 2015 and 2025 on the tehsil level. Available sources of cloud-free satellite images of NASA included Landsat 8 (OLI) in 2015 and Landsat 9 (OLI-2) or Sentinel-2 in 2025. The images were geometrically fixed, radiometrically fixed, and atmospherically fixed to make them comparable over time. With the assistance of visual interpretation and available forest cover maps, supervised classification methods were used to classify forest and non-forest classes. Post-classification comparison was used to measure change in forest area (sq. km and percent) in the two reference years.

The ArcGIS Pro software was used to perform spatial analysis to compute the tehsil-wise forest cover statistics and to determine the spatial patterns of forest loss. The data on tehsil boundaries were collected through SOI official sources of administration and superimposed on the classified forest maps to derive information on areas. These datasets were combined with spatial outputs in order to understand development-based pressures on forest resources. The integration of satellite imagery, GIS-based spatial analysis, and secondary statistical data will be a strong database to assess forest loss and its impact on sustainable development in the Satpuda fringe of North Maharashtra.

Table 1 Spatial analysis of Forest cover area in the Satpuda fringe of North Maharashtra

Year	2015		2025		Change Detection
Tehsil	Area (Sq.km)	Area (%)	Area (Sq.km)	Area (%)	Decrease Area (Sq.km)	Increase Area (Sq.km)	Decrease Area (%)	Increase Area (%)
Akkalkuwa	521.474	56.04	412.227	44.30	109.247	—	11.74	—
Akrani	1060.541	81.90	812.644	62.75	247.897	—	19.14	—
Taloda	99.426	21.87	91.020	20.02	8.405	—	1.85	—
Shahada	111.620	9.45	103.346	8.75	8.274	—	0.70	—
Shirpur	363.556	24.11	337.167	22.36	26.389	—	1.75	—
Chopda	361.092	31.36	356.755	30.99	4.337	—	0.38	—
Yaval	306.460	33.11	288.430	31.16	18.030	—	1.95	—
Raver	317.361	33.78	320.784	34.14	—	3.424	—	0.36

(Source: Calculated by researcher using ArcGIS Pro change detection analysis)

Figure 1 Tehsil-wise forest cover area in the Satpuda fringe of North Maharashtra for the years 2015 and 2025

Figure 2 Tehsil-wise percentage change in forest cover in the Satpuda fringe of North Maharashtra during 2015–2025.

Results

The dynamic analysis of the forest cover in the Satpuda fringe of North Maharashtra in the year 2015 and 2025 shows a clear and spatially uneven trend of forest loss at the level of the tehsil (Table 1). In general, the absolute forest area (sq. km) and proportional forest cover (%) decreased in most tehsils, which indicates continuous pressure on forest resources in the decade.

The greatest absolute and relative loss is seen in the tribal and forested tehsils of Akrani and Akkalkuwa which comprise the largest share of Forest loss. Akrani documented a decline of 247.90 sq. km, which is equivalent to 19.14% decline in forest cover, and Akkalkuwa lost 109.25 sq. km (11.74%). Such losses suggest that there has been massive deterioration in regions that were once able to sustain thick forest cover. Conversely, tehsils like Taloda, Shahada, Shirpur, Chopda and Yaval have had a relatively moderate loss of between 0.38 percent to 1.95 percent, but the trend is always negative.

Spatially, loss of forests is higher in the north and northeast of the study area that borders the core Satpuda ranges (Akrani and Akkalkuwa), which implies increased anthropogenic pressure in ecologically sensitive areas. The tehsils of central and southern parts like Chopda and Shahada experience relatively low forest loss, indicating the lack of forest or comparatively high control of land-use change. The overall downward trend is broken by a slight increase of 3.42 sq. km (0.36%) in Raver, which has been due to afforestation efforts and plantation growth in the satellite-based data.

The high rate of forest loss in Akrani and Akkalkuwa is aligned to areas where there is increase in population, development of infrastructure and transformation of forest land into agricultural lands (Defries et al., 2010). The increase of subsistence and commercial agriculture, along with the increase of settlements, seems to be a major cause of forest depletion (Richards, 2015). Intensive agricultural development and irrigation in the Tehsils, including Yaval and Shirpur, also depict the observable forest decline, which further confirms the connection between the land-use change and the development processes (Ayele et al., 2019).

The witnessed reduction in forest cover is a major threat to sustainable development within the Satpuda fringe. Deforestation poses a threat to biodiversity, ecosystem services, and livelihood security of tribal communities that rely on forest resources. Although there are only positive changes in Raver, which indicate that it is possible to achieve positive results with the help of specific interventions, the overall trend shows that more integrated land-use planning, more robust forest protection, and more balanced economic growth and ecology should be developed. Overall, the findings indicate that forest loss within the Satpuda fringe between 2015-2025 is spatially clustered, development pressures are closely associated, and the outcomes have important long-term sustainable development implications in North Maharashtra.

Discussion

This research paper indicates that there has been a consistent decrease in the forest cover in the Satpuda fringe of North Maharashtra between 2015 and 2025, which is indicative of larger trends of land-use change in ecologically sensitive areas in India. The scale and geographical diversity of the forest loss experienced at the tehsil level highlight the interplay between the environmental resources and development pressures.

The intense deforestation of the Akrani and Akkalkuwa tehsils is especially important since these regions traditionally form the very heart of the forested and tribal-controlled terrain of the Satpuda ranges. These tehsils were susceptible to absolute losses as development pressures increased in 2015 due to a high initial forest cover. Agricultural expansion, fuelwood harvesting and infrastructure development particularly road connectivity and settlement expansion seem to be the major causes of deforestation in these areas (Lele & Joshi, 2008). Conversely, tehsils with relatively lower forest cover to start with like Chopda and Shahada had minimal change, which indicates that the availability of forests itself limits the extent of further loss (Bone et al., 2016).

The witnessed reduction in forest cover is directly linked with population increase and agricultural development especially in tehsils where subsistence farming and irrigated agriculture has encroached into marginal forest areas (Mulatu et al., 2025). Forest clearance in tribal tehsils to cultivate, build houses and other related activities is a manifestation of livelihood-driven land-use change and not industrial-scale deforestation. But this slow and diffused conversion has cumulative effects which are also of the first importance. The decline in forest cover in tehsils like Shirpur and Yaval also lends credence to the point that agricultural intensification and better irrigation infrastructure are some of the factors that lead to forest-to-agriculture conversion (Ali & Benjaminsen, 2004).

Sustainable development wise, the further depletion of forest cover is a cause of concern in terms of stability in the ecosystem, biodiversity protection and climate stability. The degradation of forests in the Satpuda fringe poses a threat to the important ecosystem services that include soil conservation, groundwater recharge, and the local climate regulation (Móstiga et al., 2024). To tribal communities, the reduced forest resources have a direct impact on food security, availability of non-timber forest products and the traditional livelihood systems. The fact that the percentage change in forest cover in Raver tehsil was positive indicates that afforestation efforts or plantation work or better forest management can produce positive results, but the magnitude of this improvement is very small.

The results highlight the importance of combined and region-specific land-use planning that balances the development goals with the conservation of the ecological environment (Rahma Febriyanti et al., 2022). Enhancing community-based forest management, agroforestry, and controlling agricultural activities on slopes covered with forests may reduce the loss further (Jeon et al., 2013). Also, remote sensing-based monitoring, as the one used in this study, is an efficient instrument of tracking forest dynamics and evidence-based policy-making.

Although the study is effective in capturing decadal cover changes in forests through the satellite data, it fails to capture all qualitative factors of the forests including forest degradation, fragmentation or species composition. Future studies are encouraged to combine socio-economic data, field data and longer time series data to capture the causes and effects of forest loss. The association of forest change with specific development indicators would also enhance the sustainability assessment of the Satpuda fringe. On the whole, the discussion highlights the fact that the loss of forests in the Satpuda fringe of North Maharashtra is not only an environmental problem but also a development problem that requires balanced, inclusive and sustainable planning strategies.

Conclusion

The current research gives a clear evaluation of the change in forest cover in the Satpuda fringe of North Maharashtra between 2015 and 2025 through a remote sensing method. The findings show that there is a general decrease in the forest cover in most of the tehsils, and especially in the areas of Akrani and Akkalkuwa, where there are severe losses, which point to these areas as the zones of the critical ecological exposure. The spatial analysis proves that the loss of forests is not evenly distributed and is closely associated with the local development processes.

The results show that forest depletion is strongly correlated with the indicators of development like population growth, agricultural expansion, and infrastructure development. Although these processes have led to socio-economic enhancement, they have also increased the strain on the forest ecosystems, particularly in tribal dominated and forest endowed tehsils (Chettri et al., 2007). The fact that the marginal increase in forest cover in Raver tehsil was observed indicates that specific conservation initiatives, afforestation efforts, and proper land management can have positive results, yet these efforts are not widespread in the area (Clark et al., 2021).

In terms of sustainable development, further loss of forests is a major threat to the conservation of biodiversity, ecosystems, and livelihood security of communities that rely on forests. The research highlights the importance of considering the environment in the planning of regional development. The community-based forest management, agro forestry practices and controlled land use change policies are necessary to balance the development requirements with the ecological sustainability.

To sum up, remote sensing is a useful and trustworthy means of monitoring forest dynamics and helping to make informed decisions. The development strategies in the Satpuda fringe of North Maharashtra should not be focused on short-term economic benefits, but should be integrated to ensure that forest resources are protected and at the same time, the socio-economic needs are met to ensure long-term sustainability.

References

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Rathod P. P. andPawara V. L.

Department of Zoology.

*VVM’s S. G. Patil Arts, Science and Commerce College Sakri Di. Dhule 424304

E mail- pradiprathod1309@gmail.com; vilaspawara68@gmail.com

Abstract:       

The distribution of ant’s diversity in Sakri forest region of Sakri, Dhule District has been studied. Sakri forest is located to the west of Dhule city. In this forest we are collecting and an identified different type of ant’s belonging to family formicidae. This study was tried to analyze distribution of ant diversity. In Sakri forest ten different species of ant’s were identified namely Camponotus pennsylvanicus, Paraterechina longicornis, Tapinona melanocephalum, Tapinoma sessile, Technomyrmex albipes, Crematogaster, Pheidole, Monomorium minimum, Monomorium pharaonis, Solenopsis were observed. Out of these Camponotus pennsylvanicus and Tapinoma sessile was most abundant in study region.  

Key words: – formicidae, tapinoma sessile, Sakri forest, ant diversity        

INTRODUCTION

            The ant family contains more than 4.500 described species that can be found in a tropical and temperate area around the world. Ants are member of family of the social insects meaning that they live in organized colonies. Ants make up the family of Formicidae of the order Hymenoptera. Most of the described and unknown species are found in the forest, however, due to the distribution of that forest most of them will probably never be categorized. Ants are found on all continents except Antarctica, and only a few large islands. (Jones and Alice S. 2008; Thomas and Philip 2007).

            According to Shabina A. Nagariya and Santosh S. Pawar 2012 three species of ant was dominant and abundantly found. Most ant build some sort of nest under and above the ground, in trees and houses where they live and bring their food to, but are generally omnivorous, but some need special food. Myrmecology (Prons; m3rmi, from Greek; myrmex: ant and >logos, study) is the scientific study of ants, branch of entomology. Some early myrmecologist considered ant society as the ideal forms of sociality and shout to find solution to human problems by standing them.

MATERIALS AND METHODS

Study area

            The Sakri forest is situated about 55Km west of Dhule city at a latitude of 20⁰-99’-26’’. The Kan River lies on 74⁰-31’-41’’. Longitude and covers an area of the forest is fulfilling with diversity of different insects, animals and plant species. Sakri forest faces extreme variation in climatic condition with hot summer and very cold winter as well as average rainfall. The annual average rainfall in the forest ranges between 470mm to 630mm and temperature ranges between 12⁰C to 40⁰C. 

Collection of ants of family formicidae: –

Various methods of collection of ants are as per different studies. The type of vegetation determines the kind of ants, (Formicidae) were collected from the different locations of forest. The capture and collected ant species kept into dry container or directly transfer into absolute alcohol. Methods suggested by Koh (1989) namely refer for the collection and preservation of ants.

Identification of ants: – Ants (Formicidae) collected from the Sakri forest region was identified by using identification key (Mathews R. N. and Tiwari 2000; Bolten B, 1994; and Krebs C.J. 1999)

RESULT AND DISCUSSION

Ants are social insect of the family Formicidae. The family Formicidae belongs to the order Hymenoptera, which also include sawflies, bees and wasps. Fossil evidence indicates that ants were present in the late Jurassic, 150 million years ago.Ants are distinct in their morphology from their insects in having elbowed antennae, metapleural glands. Ant societies have division of labour communication between individual and an ability to solve complex problems. Ant bodies, like other insects, have an exoskeleton, and external covering that provides a protective casing around the body and a place to attached muscles.

Identified Species: –

1. Camponotus pennsylvanicus: –

Vertex of head is indented, non with a deep groove. Antenna is 10 segmented. Two Numbers of teeth present on the front of head. Eyes are large and black in color.Spines are absent on the thorax and thorax is smooth and evenly rounded when viewed from the site. One node is present.Abdomen is divided in to four segments. Small spiny hairs present on the abdomen.

2. Paraterechina longicornis: –

Vertex of head is with deep groove head pattern with foveoled punctures.  Mandible is with distinct teeth and triangular shape. Two numbers of teeth present on the head. Eyes are large and black in color. Ten segmented antennae are present. Spines are absent on the thorax. Thorax is uneven when viewed from the side. One node is present.No circle of hairs at the tip of the abdomen. Small spiny hairs are present on the abdomen and it divided into five segments.

3. Tapinona melanocephalum: –

Vertex of head indented, non with a deep groove. Head pattern is without foveolet punctures. Mandible are triangular and with distinct teeth. Two teeth present on head. Eye is large in size and reddish to orange brown in color. Ten segmented antennae are present on the head with two segmented club. Spines are absent on the thorax. Thorax is uneven when viewed from the side. One node is present. Abdomen divided into four segments. Small spiny hairs present on the abdomen. No circle of hairs at the tip of the abdomen. Stinger is absent on the abdomen.

4. Tapinoma sessile: –

Vertex of head indented, non with a deep groove. Head pattern is without foveolet punctures. Mandible is with distinct and teeth with triangular in shape. Two teeth present on the front of the head. Eye is large with reddish to orange brown in color. Twentieth segmented antennae are present on head without club.One pair of spine present on the thorax. Small spiny hairs present on the body. One node is present. Abdomen divided into four segment small spiny hairs present on the abdomen. Circle of the hairs at the tip of the abdomen are present. Stinger is absent.

5. Technomyrmex albipes: –

Vertex of hair is with deep groove head pattern without foveolet punctures.  Mandible is without teeth and elongated and linear. Numbers of teeths are absent. Eye is large in size. Body colour is reddish to orange brown.  Twentieth segmented antennae are present on the head without club.Thorax is uneven when viewed from the side. Two pair of spine present on thorax. One node is present. Abdomen divided into five segments. Small spiny hair present on the abdomen. No circle of hair at the tip of the abdomen. Stinger is absent on the abdomen.

6. Crematogaster: –

Vertex of head is with a deep groove. Head pattern is without feveolet punctures. Mandible is without teeth and triangular in shape small spiny hair present on the hair. Two teeth present on the front of the head. Eye is large in size with yellow to light brown in color. Three segmented club are present. One pair of spine present on the thorax. Thorax is uneven when viewed from the side. Small spiny hairs present on the thorax. Two nodes are present on the petiole. Circle of hair present at the tip on the abdomen. Abdomen is divided into four segments. Small spiny hairs present all over the body. Stingers are present on the abdomen.

7. Pheidole: –

Vertex of head is with deep groove. Head pattern is with fovelolet punctures. Mandible are without teeth and triangular in shape. Eye size is small with reddish to orange brown in color. Twentieth segmented antennae are present on the head with three segmented club. No teeth are present on the front of head. One pair of spine present on the thorax. Thorax is uneven when viewed from the side. Small spiny hairs present all over the body. Two nodes are present. Abdomen divided into four segment and small spiny hair present on the abdomen. Circle of hairs are present at the tip of the abdomen and stinger are absent.

8. Monomorium minimum: –

Vertex of head with a deep groove and head pattern is foveolet punctures mandible with distinct teeth, elongated and linear in shape two teeth are present on the front of head. Eyes are large and black in color. 10 segmented antennae are present with three segment club. Spines are absent on the thorax. Thorax is smooth and evenly rounded when viewed from the side. Small spiny hairs are present on the thorax. Two nodes are present on petiole. Circle of hair present at the tip of abdomen. Abdomen is divided into four segment and stinger are absent on the abdomen. Small spiny hairs present all over the body.

9. Monomorium pharaonis: –

Vertex of head is indented, non with a deep groove. Head pattern is with foveolet punctures and mandible is with a distinct tooth. Mandible shape is elongated and linear. Eyes are small in size. Eye color is black. Twentieth segmented antennae are present on head. Two teeth are present on the front of head. Spine is absent on the thorax. Thorax is smooth and evenly rounded when viewed from the side. And two nodes are present on petiole. Abdomen is divided in to four segmented and circle of hair present at tip of abdomen. Small spiny hairs are present all over the body. Stringers are present on the abdomen.

10. Solenopsis: –

Vertex of head is indented, non with a deep groove. Head pattern is without foveolet punctures mandible is with distinct teeth. Mandible shape is elongated and linear.  One pair of teeth present on front of the head. Eyes are small in size. Eye color is reddish to orange brown. Ten segmented antennae are present on head is with a two segmented club. Spine is absent on the thorax. Thorax is uneven when viewed from the side. Abdomen is divided in to four segmented and circle of hair present at tip of abdomen. Small spiny hairs are present all over the body.

Camponotus pennsylvanicus	Paraterechina longicornis
Tapinona melanocephalum	Tapinoma sessile
Technomyrmex albipes	Crematogaster
Pheidole	Monomorium minimum
Monomorium pharaonis	Solenopsis

CONCLUSION

            The present study has been focused on diversity of ants and its environmental associations. Our results will help for assessing the richness and diversity of ants. This investigation also focuses on reducing the number of ant species due to human activity and helps in improve social and cultural importance of forest and its scenario.

ACKNOWLEDGEMENT

            Authors are thankful to the Interdisciplinary Research Laboratory of Department of Zoology VVM’s S. G. Patil Arts, Science and Commerce College Sakri Di. Dhule, for providing research related facilities. A special thanks to Prof. S. S. Patole and Prof. L. B. Pawar for kindly support us for identification of different ant species. Also thankful to local peoples of Sakri helped us in collection of ants from different spots and regions and gratefully acknowledged.

REFERENCES

1. Bolton B. (1994): Identification guide to the ant genera of the world, London: Harvard
   1. University Press. pp. 222.
2. Koh, L. P. and Wilcove, D. S. (2008): Is oil palm agriculture really destroying tropical biodiversity?’, Conservation Letters, 1. pp. 27-33
3. Krebs, C.J., (1990): Ecological methodology, Addison- Educationall publishers, California, pp.581
4. Mathew R.N. Tiwari, (2000): Insecta: Hymenoptera: Formicidea.State Fauna Series 4,Zoological Survey of India Fauna of Meghalaya, 7: pp. 251-409.
5. Shabina A. Nagariya and Santosh S. Pawar (2012): Distribution of (Hymenoptera: Formicidae) Ants diversity in Pohara Forest Area of Amravati Region, Maharashtra  State, India., International Journal of Science and Research Vol.3. (7).,pp. 1310-1312
6. Thomas, Philip (2007): “Pest Ants in Hawaii”. Hawaiian Ecosystems at Risk project  (HEAR). Retrieved 6 July 2008.

P. K. Patil^a, Dr. D. B. Salunkhe^b*, Dr. H. S. Gavale^c*

^aDept. Of Physics, S.S.V.P.S’s L. K. Dr. P. R. Ghogrey Science College, Dhule

^bDepartment of Physics, KVPS Kisan ACS College Parola Dist Jalgaon 425111

^c Dept Of Physics, Z. B. Patil College, Dhule

Abstract:
The production of semiconductor materials which are lead free and eco-friendly has become a more focus of research into sustainable and renewable energy. The need for safe, eco-friendly and sustainable solar energy materials has increased interest in lead-free photovoltaic technologies. Silver bismuth chalcogenides, namely AgBiS₂ and AgBiSe₂, are promising absorber materials because they are environmentally friendly, chemically stable, and made from relatively abundant elements. These materials have suitable band gaps, absorb light strongly, and can tolerate crystal defects, which are important for efficient solar cell performance. AgBiS₂ and AgBiSe₂ thin films can be produced using low-cost and scalable methods such as spin coating, successive ionic layer adsorption and reaction (SILAR), hydrothermal synthesis, and other solution-based techniques. These methods are suitable for large-area and flexible solar devices. In addition, AgBiS₂ and AgBiSe₂ show better thermal and environmental stability compared to lead-based perovskite materials. This review summarizes recent progress in their synthesis, structural and optical properties, and photovoltaic performance. The main challenges, including charge transport and interface losses, are discussed, along with future research directions to improve efficiency and long-term stability.

Keywords:AgBiX₂, AgBiS₂, AgBiSe₂, eco-friendly, lead-free chalcogenides, photovoltaics, sustainable energy, solar devices.

1.Introduction:

The rising global demand for energy and increasing environmental concerns have intensified research into renewable energy sources. Solar energy is considered one of the most promising options because it is clean, abundant, and sustainable [1,2]. However, conventional silicon-based solar cells involve high-temperature processing and costly manufacturing steps, which limit their economic feasibility for large-scale deployment [3]. This has motivated the search for alternative photovoltaic materials that are efficient, low-cost, and environmentally benign [4,5].

Lead-based perovskite solar cells have demonstrated rapid improvements in power conversion efficiency in recent years [6,7]. Despite this progress, their commercial application is hindered by the presence of toxic lead and poor long-term stability under moisture, heat, and continuous light exposure [8–10]. These issues have driven significant efforts toward the development of lead-free photovoltaic materials with improved environmental safety and operational stability [11,12].

Chalcogenide semiconductors have emerged as attractive candidates for lead-free solar cells due to their high optical absorption, tunable band gaps, and good chemical stability [13–15]. Among them, silver bismuth chalcogenides, particularly AgBiS₂ and AgBiSe₂, have received growing attention as sustainable absorber materials [9-13]. These compounds consist of relatively non-toxic and earth-abundant elements and possess band gap energies well suited for solar energy conversion [8-12]. Their strong light absorption enables efficient photon harvesting in thin films, while their defect-tolerant nature helps suppress non-radiative recombination losses [2].

AgBiS₂ and AgBiSe₂ are also compatible with low-cost and scalable fabrication techniques, including spin coating, successive ionic layer adsorption and reaction (SILAR), and hydrothermal synthesis [14]. These solution-based methods allow large-area deposition and integration with flexible substrates [9]. In addition, silver bismuth chalcogenides exhibit improved thermal and environmental stability compared to lead-based perovskite materials, making them promising for long-term photovoltaic applications [8].

This review presents an overview of recent progress in AgBiS₂ and AgBiSe₂-based photovoltaic materials, covering synthesis routes, structural, optical, and electrical properties, and device performance [10,11]. Key challenges related to charge transport, interface engineering, and efficiency optimization are discussed, and future research directions are proposed to advance stable, efficient, and environmentally friendly solar cell technologies [11].

2. Properties and Crystal Structure:
1. Crystal Structure

AgBiS₂ and AgBiSe₂ are ternary chalcogenide semiconductors composed of silver, bismuth, and sulfur or selenium. These materials generally crystallize in a cubic or near-cubic crystal structure, which is favorable for uniform thin-film formation [1,2]. In the crystal lattice, Ag⁺ and Bi³⁺ ions occupy metal sites and are coordinated by S²⁻ or Se²⁻ anions [3].

Their atomic arrangement resembles a rock-salt-type framework, where metal–chalcogen bonds form a compact and symmetric network [4]. This structural symmetry allows the materials to accommodate a certain level of lattice disorder without severe degradation of electronic properties [5]. Such defect tolerance is particularly beneficial for solution-processed films, where perfect crystallinity is difficult to achieve [6].

2. Optical and Electrical Properties

AgBiS₂ and AgBiSe₂ exhibit strong absorption in the visible region, with absorption coefficients high enough to enable efficient light harvesting in thin absorber layers [7,8]. AgBiS₂ mainly absorbs visible light, while AgBiSe₂ has a slightly narrower band gap, allowing absorption to extend into the near-infrared region [9,10].

1. Optical Absorption Behaviour

AgBiX₂ (X = S, Se) materials show strong light absorption in the visible and near-infrared (NIR) regions, which is essential for efficient solar energy harvesting. UV–Vis absorption studies typically reveal a clear and sharp absorption edge, indicating good crystallinity and a well-defined electronic band structure. These materials possess high absorption coefficients in the range of about 10²–10⁵ cm⁻¹, allowing effective photon absorption even with very thin films. This property is particularly beneficial for low-cost and flexible photovoltaic devices.

Replacing sulfur (S) with selenium (Se) causes the absorption edge to shift toward longer wavelengths. This red shift occurs due to the larger atomic size and higher polarizability of selenium. As a result, the material can absorb a broader portion of the solar spectrum, improving light utilization in photovoltaic applications.

• Band Gap Energy

The optical band gap (Eg) of AgBiX₂ compounds is commonly determined using Tauc plots derived from UV–Vis absorption measurements. These materials typically exhibit direct or quasi-direct band gap characteristics, which are advantageous for optoelectronic and photovoltaic applications.

AgBiS₂ generally shows a band gap in the range of 1.2 to 1.6 eV. In comparison, AgBiSe₂ has a smaller band gap, usually between 0.9 and 1.2 eV. This reduction in band gap allows AgBiSe₂ to absorb light over a wider wavelength range.

Both band gap values fall close to the optimal range required for efficient solar energy conversion, enabling effective utilization of the solar spectrum [2–3]. Furthermore, the band gap of these materials can be tuned through anion substitution (S to Se), nanostructure formation, and defect engineering, enhancing their suitability for photovoltaic devices.

• Photoluminescence (PL) Characteristics

Photoluminescence analysis provides valuable insight into charge carrier recombination processes and the presence of defects in AgBiX₂ materials. These compounds generally show weak to moderate PL emission, which indicates reduced radiative recombination and efficient separation of photo-generated charge carriers. Such behavior is highly desirable for applications in solar cells and photocatalysis.

The observed PL emission peaks are commonly attributed to recombination occurring near the band edge as well as defect-related states, including sulfur or selenium vacancies and antisite defects. Lower PL intensity suggests suppressed electron–hole recombination, which contributes to improved photovoltaic and photocatalytic performance [6].

Electrical Properties and Charge Transport:

Electrical characterization reveals that AgBiX₂ materials generally show p-type conductivity, primarily arising from intrinsic defects such as silver vacancies [1,2]. Synthesis conditions and post-deposition treatments have a strong influence on charge carrier concentration, mobility, and electrical resistivity [3,4]. Enhanced crystallinity and reduced defect density improve charge transport and suppress recombination losses, resulting in improved electrical performance [5–7]Both compounds behave as semiconductors and show effective generation of charge carriers under illumination [11]. Their electronic structure supports the transport of electrons and holes with relatively low recombination losses. Importantly, AgBiS₂ and AgBiSe₂ are known for their defect-tolerant nature, where common point defects do not form deep trap states that severely limit carrier lifetime.

3. Thermal and Environmental Stability

A major advantage of AgBiS₂ and AgBiSe₂ is their high thermal and environmental stability compared to lead-based perovskite absorbers [12,13]. These materials retain their structural and optical properties when exposed to air, moisture, and moderate heating conditions [7].

The strong metal–chalcogen bonds in silver bismuth chalcogenides provide chemical robustness, reducing the risk of phase degradation or decomposition during long-term operation [18,19]. Several studies have reported stable performance of AgBiS₂ and AgBiSe₂ thin films under continuous light exposure and extended storage periods [20–22]. This stability makes them suitable candidates for durable and reliable photovoltaic devices.

In summary, AgBiS₂ and AgBiSe₂ possess favorable crystal structures, strong optical absorption, suitable band gaps, and defect-tolerant electronic properties [21,22]. Their excellent resistance to thermal and environmental degradation further enhances their potential as lead-free absorber materials for sustainable photovoltaic applications [15-18].

3.1Chemical Synthesis Approaches for AgBiS₂ and AgBiSe₂ Thin Films:

1. Successive Ionic Layer Adsorption and Reaction (SILAR)

SILAR is a solution-based deposition technique that is widely applied for the preparation of AgBiS₂ and AgBiSe₂ thin films because of its simplicity and low processing cost [1,2]. The method involves repeated dipping of the substrate into cationic and anionic solutions, separated by rinsing steps. Silver and bismuth ions are adsorbed from metal salt solutions, followed by reaction with sulfur or selenium ions to form the chalcogenide layer on the substrate surface [3].

The thickness and composition of the films can be adjusted by controlling the number of deposition cycles, solution concentration, and immersion time [4]. Doping can be conveniently introduced by adding suitable dopant ions into the metal precursor solution, allowing easy modification of the film properties without complex processing steps [5,6]. Due to its low-temperature operation and suitability for large substrates, SILAR is well suited for cost-effective photovoltaic fabrication.

2. Chemical Bath Deposition (CBD)

Chemical bath deposition is a commonly used technique for producing chalcogenide semiconductor films with uniform coverage [7]. In this method, the substrate is placed in a reaction bath containing metal precursors, a sulfur or selenium source, and complexing agents that regulate the release of ions into the solution [8]. Controlled chemical reactions in the bath lead to gradual film growth on the substrate.

Film quality, including thickness, grain size, and stoichiometry, can be tailored by varying parameters such as bath temperature, pH, and deposition duration [9]. Doping is achieved by introducing small amounts of dopant salts into the bath, enabling uniform incorporation during film growth [10,11]. Post-deposition heat treatment is often applied to improve crystallinity and electrical performance [12].

3. Hydrothermal Method

The hydrothermal method involves chemical reactions carried out in sealed vessels at elevated temperature and pressure [13]. This approach allows the synthesis of AgBiS₂ and AgBiSe₂ materials with high crystallinity and controlled morphology [14]. Metal salts and chalcogen sources are dissolved in aqueous or mixed solvents and heated under carefully controlled conditions.

Dopant elements can be added directly to the precursor solution, leading to uniform dopant distribution throughout the material [15,16]. Although hydrothermal synthesis produces high-quality materials, its use in large-area thin-film deposition is limited. Therefore, it is mainly employed for nanostructured absorbers and fundamental material studies.

4. Spin Coating of TiO₂ Base Layer

Spin coating is a widely adopted technique for depositing compact and uniform TiO₂ layers that act as electron transport layers in photovoltaic devices [17]. A TiO₂ precursor solution or diluted paste is dropped onto the substrate and spread evenly by rapid rotation [18].

The final film thickness is influenced by the spin speed, spinning time, and solution viscosity [19]. After coating, thermal treatment is usually applied to enhance film densification and charge transport properties [20]. A well-prepared TiO₂ base layer improves interfacial contact and facilitates efficient electron extraction from AgBiS₂ or AgBiSe₂ absorber layers [21,22].

In summary, SILAR and CBD are particularly effective for depositing doped AgBiS₂ and AgBiSe₂ thin films using low-cost and scalable solution-based techniques. The hydrothermal method provides high-quality crystalline materials but is less suitable for large-area films. Spin coating remains an efficient and reliable approach for preparing TiO₂ base layers, contributing to improved photovoltaic device performance

3.3 Post-Deposition Treatments and Performance Enhancement

After film deposition, additional processing steps are often required to improve the quality and performance of AgBiS₂ and AgBiSe₂ thin films. These post-deposition treatments help enhance crystal structure, reduce defects, and improve charge transport within the photovoltaic device [1,2].

A) Heat Treatment (Annealing)

Heat treatment is widely applied to improve the structural properties of AgBiS₂ and AgBiSe₂ films [3]. Annealing is typically performed in air, inert atmospheres, or sulfur- or selenium-rich environments. This process allows atoms within the film to rearrange into a more ordered structure, leading to larger grain sizes and improved crystallinity [4].

Annealing also removes residual solvents and improves film compactness, which enhances electrical conductivity and reduces carrier recombination [5]. However, excessive heating may cause chalcogen loss or phase instability, making careful optimization of annealing conditions essential [6].

B) Sulfurization and Selenization Treatments

Exposure of deposited films to sulfur or selenium vapor is commonly used to correct compositional deficiencies and improve phase quality [7]. Such treatments help compensate for sulfur or selenium vacancies that can form during film growth [8].

By reducing these vacancies, carrier transport properties are improved, resulting in enhanced photovoltaic performance [9]. Chalcogen-rich treatments are particularly beneficial for films prepared by solution-based methods, where slight non-stoichiometry is often observed [10].

C)Surface and Interface Modification

Surface treatments are important for minimizing charge losses caused by surface defects [11]. Chemical passivation techniques can reduce dangling bonds and surface trap states, leading to improved carrier lifetime [12].Engineering the interface between AgBiS₂/AgBiSe₂ absorber layers and the TiO₂ electron transport layer is also crucial. Improved interface quality enhances charge transfer and suppresses interfacial recombination, contributing to higher device efficiency [13,14].

D) Post-Treatment of TiO₂ Base Layer

The performance of the TiO₂ base layer can be significantly improved through post-deposition treatment [19]. Thermal annealing enhances TiO₂ crystallinity and electron mobility, while surface treatments reduce trap states at the TiO₂ surface [20].

An optimized TiO₂ layer provides better electronic contact with the absorber material, enabling efficient electron extraction and reducing recombination losses at the interface [21,22].

4.Morphological and Structural Characteristics

AgBiS₂ and AgBiSe₂ thin films generally exhibit smooth and well-covered surfaces with uniform grain distribution when prepared using solution-based techniques. Optimized deposition conditions and post-deposition heat treatment promote grain growth, resulting in fewer grain boundaries that support improved charge transport. The film thickness typically lies in the sub-micron to micron range, providing effective and uniform light absorption across the absorber layer. Structural studies, such as X-ray diffraction, confirm that these materials commonly crystallize in cubic or near-cubic phases. Thermal treatment further enhances crystallinity and phase stability. A reduced density of structural defects contributes to better electrical transport properties. Together, these morphological and structural features play a crucial role in achieving efficient and stable photovoltaic device performance.

7Applications for Sustainable Energy

Silver bismuth chalcogenides such as AgBiS₂ and AgBiSe₂ are increasingly explored for sustainable energy applications because they are free from toxic lead, absorb light efficiently, and show good operational stability [1,2]. Their suitable band gap energies make them effective light-absorbing layers for thin-film solar cells [3]. In addition, these materials can be deposited using inexpensive and scalable solution-based techniques, allowing the fabrication of large-area and flexible photovoltaic devices [4].

Beyond solar cells, AgBiX₂ materials have demonstrated potential in photocatalytic processes, including solar-driven water splitting and the breakdown of environmental pollutants, due to their strong visible-light response and effective charge carrier separation [5,6]. Their chemical robustness supports stable performance under prolonged illumination [7]. Overall, silver bismuth chalcogenides offer a promising and environmentally friendly pathway for advancing next-generation sustainable energy technologies [8–10].

8Problems and Future Prospects

Despite the significant progress achieved with AgBiX₂ materials, several challenges still need to be addressed. These include achieving precise control over material stoichiometry, suppressing the formation of secondary phases, and ensuring long-term device stability. Improving performance further will require effective strategies such as controlled doping, interface engineering, and defect passivation. Future research should focus on developing scalable fabrication methods and gaining a deeper understanding of defect-related physics, which are essential steps toward the commercial realization of AgBiX₂-based energy devices.

9.Conclusion

Silver bismuth chalcogenides, namely AgBiS₂ and AgBiSe₂, have gained considerable attention as lead-free materials for sustainable energy applications. Their suitable band gap energies, strong optical absorption, defect-tolerant behavior, and good thermal and environmental stability make them highly promising for use in photovoltaic and photocatalytic systems. Moreover, these materials can be synthesized using low-cost and scalable solution-based methods, enabling their application in large-area devices. With further advancements in controlled synthesis, doping techniques, and interface engineering, the performance of AgBiS₂ and AgBiSe₂ is expected to improve further, strengthening their potential as environmentally friendly alternatives for next-generation solar energy technologies.

References

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