Department of Physics
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Item Fabrication of Metal Oxide Based Charge Transport Layer for Energy Conversion Devices(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2025) Kainat Ishtiaq; CIIT/SP24-RPH-011/LHR; Dr. Ishrat Sultana; LHR TP 10123Energy conversion devices such as perovskite solar cells, dye-sensitized solar cells, and electrochemical energy storage systems have gained significant attention due to their potential to provide efficient, low-cost, and sustainable alternatives to conventional energy technologies. A critical factor influencing the performance of these devices is the charge transport layer, which governs charge extraction, transport, and recombination processes at the interfaces. In this study, nickel oxide (NiO) and zinc oxide (ZnO) were synthesized and investigated as hole transport and electron transport materials, respectively, along with their LC sheet–based composite counterparts, for application in energy conversion and storage devices. NiO and ZnO nanoparticles were successfully synthesized using a simple and cost-effective coprecipitation method, while LC sheet–based composites were developed using corn fiber as a sustainable carbon source to enhance electrical conductivity and interfacial contact. The structural, electrochemical, and vibrational properties of the prepared materials were systematically characterized using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and Raman spectroscopy. CV analysis revealed that pristine NiO and ZnO exhibited pseudocapacitive behavior due to reversible redox reactions, whereas LC sheet–based composites showed predominantly capacitive behavior with improved rate capability, reversibility, and charge–discharge performance. The enhanced electrochemical performance of the composites is attributed to the conductive carbon network provided by the LC sheet, which facilitates rapid electron transport and efficient ion diffusion.Item Synthesis and Simulation of Metal Oxide based Nanostructures for Thin-Film Solar Cell Applications(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2020) Muqaddas Akram; CIIT/FA18-RPH-035/LHR; Dr. Ishrat Sultana; LHR TP 6091In this work, we employed a solution-based hydrothermal process to synthesize the Zinc Oxide (ZnO) nanorods on a coated glass substrate. For the growth process, metal oxide with a thickness <300 was used as a seed layer for further growth of nanostructures. The glass substrate coated with metal oxide was then immersed in the precursor solution, then a hydrothermal process was performed at 90 ° C using different types of growth hours. The length and diameter of ZnO nanorods were controlled by varying the growth time, the concentration of the precursor solution and the temperature etc. Scanning electron microscope (SEM) images were used to determine the surface morphology of metal Nano-oxide rods. Characterization of the optical transmission (full and diffuse) was performed using a UV-Vis spectrophotometer. In addition, the photovoltaic device was simulated using (ZnO) and amorphous silicon layers (p, i, n) from thin film solar cell (TFSC) functions.Item Development of Biochar Based Metal Oxide and Metal Sulfide for Their Applications in DSSCs(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2025) Hasaan Mahmood; CIIT/FA23-RPH-019/LHR; Dr. Ishrat Sultana; LHR TP 9850Dye-Sensitized Solar Cells (DSSCs) emerge as a promising alternative to traditional silicon-based solar technologies due to their low cost, simple fabrication, and environmental friendliness. However, their performance is often limited by poor charge transport and recombination losses. To address these issues, this research focuses on developing a biochar-based composite using tin oxide (SnO₂) and tin sulfide (SnS₂) for application in DSSCs. SnO₂ was chosen for its excellent electron transport capabilities and chemical stability, while SnS₂, with its narrow bandgap, contributed to efficient light absorption. Biochar, derived from biomass, was incorporated into the system to enhance electrical conductivity, provide a high surface area for dye loading, and serve as a cost- effective and sustainable alternative to synthetic conductive materials. The combination of biochar with SnO₂ and SnS₂ resulted in a composite that improved charge separation and reduced electron recombination, leading to better overall device performance. Detailed structural and optical characterizations were performed to confirm the successful formation of the composite and its desirable properties. Electrochemical analyses demonstrated improved charge transfer behavior and lower internal resistance within the cell. The modified DSSCs showed a noticeable increase in power conversion efficiency compared to conventional configurations. This study not only presents a novel material approach for enhancing DSSC performance but also supports the use of eco-friendly and affordable components in solar energy applications, paving the way for more sustainable photovoltaic technologies in the future.