There are tremendous efforts to channelize solar energy into usable form using green and sustainable technologies. Hydrogen is envisioned as ideal energy carrier for future energy demands. It has low density, high thermal conductivity and strong chemical reducing properties, which makes it apt for many applications. Among several renewable routes to produce hydrogen, photoelectrochemical (PEC) cell is an advanced technology for generation of hydrogen energy from solar light and water. This engraving technology has motivated a surge of development in solar active semiconducting nanostructures. Among various semiconductors, CdS is one of the most studied photoanodic materials due to its low bandgap and well-suited band edge positions. The research in the present dissertation has been aimed to synthesize CdS thin films by a low-cost industrially scalable technique. Among different solution based low-cost technologies, spray pyrolysis is one of the most desirable methods to produce uniform adherent semiconducting thin films with low production cost, simplicity of operation, ease of doping and large-scale production. Various parameters were varied *viz.* temperature of deposition, film thickness to obtain optimized CdS thin films showing superior performance in PEC cell. However, after prolonged PEC operation it was found that photocurrent generated by CdS photoanode decreases with time. This characteristic of CdS is associated with a problem of undesirable decomposition of photoanode upon prolonged irradiation in an electrolyte. This instability in aqueous media is major cause of concern to visualize CdS as an ideal photoanode for PEC cell. Hence, efforts have been focused on the stabilization of CdS photoanode for sustained photoelectrochemical water splitting system using different methods: (1) Stable metal oxide coatings that protects the surface of CdS wherein titania and niobia metal oxides were explored, which exhibited improved stability; (2) Cost effective and earth abundant co-catalysts such as metal oxides, hydroxides and sulphides were loaded onto spray deposited CdS and PEC performance was examined.
Alka Pareek received B. Sc. degree in physics from Maharishi Dawanand Saraswati University, Ajmer in 2008, M.Sc. degree in Physics from Devi Ahilya Vishwa Vidhyalaya in 2010 and submitted Ph.D. thesis in Materials Engineering from University of Hyderabad in 2015. She has carried out her Ph.D. research work in International Advanced Research for Powder Metallurgy and New Materials (ARCI) from 2010-2015. She has published 5 publications in International journals and 3 conference proceedings. She has presented her work in various conferences in India and abroad during her Ph.D. and achieved best oral presentation award in ISEAC- 2014 and ICEE-2015. Her research interest includes materials for energy research with special focus on nanostructured material for hydrogen generation, Semiconductor thin film material, Photoelectrochemical characterization of materials.