Browsing by Author "Anamika Chaudhari"

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Biosynthesis of TiO2 nanostructures using Camellia sinensis extract (polyphenols) and investigation of their execution as photoanodes in photovoltaic device
(Elsevier B.V., 2024) Aman Kumar; Anamika Chaudhari; Sudhanshu Kumar; Suman Kushwaha
Titanium dioxide (TiO2) nanoparticles (NPs) are indeed widely recognized and utilized as one of the most prominent photoanode materials in dye-sensitized solar cells (DSSCs). Therefore continuous efforts have been made to improve the performance of TiO2 photoanodes in terms of light absorption, charge carrier mobility, and overall energy conversion efficiency. Green synthesis methods for the production of TiO2 NPs, including the use of plant-based reducing agents, have gained significant attention in recent years. These methods are considered environmental friendly alternatives to traditional physical and chemical synthesis methods, which often involve the use of hazardous chemicals and complex processes. Therefore, in this work, a variety of tea types, including green, white, black, oolong, pu-erh have been used to synthesize TiO2 NPs. The differences in the amount of phenolic compounds and caffeine in various tea varieties can influence the topology, structure, and composition of the as synthesized nanoparticles (NPs). The prepared TiO2 NPs were comprehensively characterized for particle size, morphology, purity, composition, crystalline nature, structural, electrochemical and photovoltaic capabilities. The as synthesized titanium oxide (TiO2) NPs were spherical in shape and particle sizes ranged from 10 to 20 nm with little agglomerations. For DSSC application, thin films of synthesized TiO2 NPs were prepared by making paste of TiO2 NPs with Triton-X and spread onto conducting substrate (FTO) with the help of glass rod and finally sintering for 1 h at 450 °C. The prepared TiO2 electrodes were dipped in the standard N719 dye solution (0.1 × 10−3 M) in acetonitrile medium overnight for complete adsorption. Overall efficiency = 3.0 %, JSC = 9.72 mA/cm2, VOC = 660 mV and FF = 0.46 was achieved with the DSSC made up with green tea mediated TiO2 NPs based photo anode. Due to high phenolic content and good reductive properties, TiO2 NPs prepared using green tea extract were highly crystalline in nature, have high surface area, high roughness factor, good stability which results in maximum dye loading and hence increase in the overall conversion efficiency. © 2024 Elsevier B.V.
Comparative study of natural and synthetic dyes in DSSCs: An experimental and computational approach
(Elsevier B.V., 2024) Aman Kumar; Anamika Chaudhari; Sudhanshu Kumar; Suman Kushwaha; Sudip Mandal
This study explores the natural and synthetic dyes as sensitizers for dye-sensitized solar cells (DSSCs). Anthocyanin dye extract (PG) from pomegranate (Punica granatum) fruit, betanin pigment (BR) from beetroot (Beta vulgaris), and the commercially available organic dye, Rose Bengal (RB), were investigated as sensitizers for DSSCs and their photovoltaic performances were recorded. Density functional theory (DFT) and time-dependent DFT (TD-DFT) studies have also been performed in order to get insight into the photophysical and photoelectrochemical properties. The overall efficiencies (η) of 0.34%, 0.30%, and 0.25% were obtained for the PG, BR, and RB dyes under 1 sun illumination, respectively. The results infer that PG dye would act as a promising photo-sensitizer for DSSCs as compared to BR and RB sensitizers, which may be due to better interaction between anthocyanin molecule of pomegranate extract and TiO2. © 2024 Elsevier B.V.
Investigating the potential compatibility of various rhodamine derivatives in dye-sensitized solar cells using an experimental and computational approach
(Elsevier B.V., 2025) S. Dasaratha Kumar; Aman Kumar; Anamika Chaudhari; Sudip Mandal; Suman K. Kushwaha
Rhodamine derivative based dyes like Rhodamine 6G (R6G), Rhodamine B (RB), Rhodamine 123 (R123), Rhodamine B Isothiocyanate (RB-iso), Sulfo Rhodamine B sodium salt (RB-sulfo) were investigated through density functional theory (DFT) and time-dependent DFT (TD-DFT) for their potential suitability as sensitizers in dye-sensitized solar cells (DSSCs). Out of five dyes, the photovoltaic properties of the three dyes (viz. R123, RB, and RB-sulfo) were investigated experimentally. UV–vis absorption studies were performed to investigate the optical properties of dyes and dye adsorbed onto TiO2 surface. DSSC made with RB dye exhibited notably better power conversion efficiency (η) of 0.15% with short-circuit photocurrent density (JSC) of 0.66 mA cm−2, open-circuit photovoltage (VOC) of 0.426 V and fill factor (FF) of 0.54, as compared with other two dyes (RB-sulfo and R123). Findings suggest that RB dye is the most effective sensitizer among other Rhodamine derivative dyes tested as sensitizers in DSSCs. A higher molar extinction coefficient, broad light absorption range, and strong adsorption onto the TiO2 surface make it a better choice for enhancing the performance of DSSCs. These characteristics enable RB to achieve a higher overall power conversion efficiency than other Rhodamine derivatives. © 2025 Elsevier B.V.
Investigation of Dye Concentration Variations and Their Impact on Dye-Sensitized Solar Cell Efficiency
(John Wiley and Sons Inc, 2025) Anamika Chaudhari; Aman Kumar; S. Dasaratha Kumar; Bhawana Tripathi; Shweta Singh; Sudip Mandal; Suman K. Kushwaha
This study investigates the dye concentration dependent study on the performance of dye-sensitized solar cells (DSSCs) by examining key characterization techniques, including UV-Vis, IR, Raman, EIS, J-V measurements and J-t transient analysis. Increasing dye concentration enhances light absorption, as observed through UV-Vis spectra, leading to an initial increase in Jsc in the J-V measurements. However, beyond an optimal concentration, excessive dye loading leads to aggregation and a reduction in electron injection efficiency, as evidenced by an increase in charge transfer resistance in the EIS spectra. This also results in increased recombination and reduced fill factor, ultimately lowering the overall conversion efficiency. The J-t analysis further reveals that higher dye concentrations slow the current stabilization and cause faster decay rates due to higher recombination. Optimal dye concentrations strike a balance between light absorption, electron injection, and recombination, resulting in high efficiency and stable performance. The highest efficiency (1.1%) is achieved with a moderate concentration of 0.1 mM of mercurochrome dye. © 2025 Wiley-VCH GmbH.
Synthesis of TiO2 nanoparticles by green approach: Application as photoanode for dye-sensitized solar cells
(Elsevier Ltd, 2024) Anamika Chaudhari; Aman Kumar; Sudhanshu Kumar; Suman Kushwaha
Efficient photoanodes play a central role in the performance of dye-sensitized solar cells. Traditional methods for synthesizing TiO2 often involve chemical processes that can be expensive and environmentally harmful due to the use of toxic and hazardous substances. Therefore in this work, TiO2 nanoparticles (NPs) were synthesized using bio-inspired processing through a hydrothermal procedure using different concentrations of Aloe barbadensis miller leaves extract as the reducing and stabilizing agent. Scanning electron microscopy (SEM), UV–vis spectroscopy (UV), X-ray difraction (XRD), Raman Spectroscopy, transmission electron microscopy (TEM) and Brunauer–Emmett–Teller (BET) analysis were used to characterize as synthesized TiO2 NPs. DSSCs were fabricated employing the prepared TiO2 NPs as photoanodes, and their performance was assessed. DSSC generates JSC of 9.7 mA/cm2, VOC of 0.682 V and efficiency (η) of 4.3 % when 20 mL concentration of extract was used for the synthesis of TiO2 NPs and subsequently their photoanodes. © 2024 Elsevier Ltd
Thin-film fabrication techniques in dye-sensitized solar cells for energy harvesting
(wiley, 2024) Aman Kumar; Anamika Chaudhari; Sudhanshu Kumar; Suman Kushwaha; Sudip Mandal
From the last few decades, dye-sensitized solar cells (DSSCs) have emerged out as economical and reliable substitutes for energy source owing to their simple preparation, cheap cost, low toxicity, and competitive efficiency. The key components of DSSCs include the semiconducting thin film, sensitizer, redox couple, and counter electrode. The photoanode, which is made of a semiconducting thin film with a dye adsorbed on it, plays a crucial role in DSSCs, and its morphology depends on the deposition techniques used. Various established physical and chemical coating/deposition methods are promising for attaining high-quality thin films for DSSC fabrication. The morphology and particle size of the thin films strongly depend on the deposition techniques employed. Surface and interfacial effects significantly impact the whole performance of these films, leading to improved properties and characteristics compared to bulk materials. Highly functionalized thin films have their benefits when used as photoanodes in DSSCs, as the boosted functional properties of materials can be exploited at the nanoscale level. There are several techniques for depositing thin films, including physical, chemical, and colloidal routes. Some widely used methods include spray pyrolysis, sol-gel, plasma spray, electrophoretic deposition, screen printing, and dip coating. Vacuum deposition techniques such as magnetron sputtering and pulsed laser deposition are successfully established in the thinfilm coating industry due to the high quality and reproducibility of the fabricated thin films. While these techniques often require expensive equipment and complex experimental setups, they offer the advantage of producing thin and dense films. Colloidal, doctor blade, and dip coating techniques are advantageous because of their low cost and simplified experimental setup and equipment. These techniques produce thin films with controlled structures and particle size distributions. However, they may be prone to issues such as cracks, pores, or layer separation, which can be overcome by repeating the coating process several times intermittently. Sol-gel and slurry methods are extensively used to fabricate nanocrystalline thin films in DSSCs due to their lower cost than gas-phase methods. However, the meager stability of the precursors against hydrolysis remains a concern. The SILAR (successive ionic layer adsorption and reaction) method is another solution-based thin-film deposition technique, a modified version of chemical bath deposition. The resulting thin films exhibit improved grain structure orientation. In short, various deposition techniques are employed to fabricate thin films for DSSCs, each with its advantages and challenges. Researchers continue to explore and optimize these techniques/methods to improve the overall performance of DSSCs. © 2024 Scrivener Publishing LLC. All rights reserved.