Solar Energy Conversion via Low-Cost Nanostructured Thin Films

Photo-electrochemical water splitting is a part in solar energy harvesting to produce hydrogen, which can be used as a carrier of energy in fuel cells. All techniques for electrochemistry, surface analysis and conditions employed for experimental are reported.The formation and investigation of photo-active thin nanostructured WO3 films were studied. The time dependence of photo-currents is studied by impedance, light pulse, and light modulation techniques and also electron transport are discussed. Evidence for trapping of diffusing electrons is obtained from intensity modulated photocurrent spectroscopy. Layer-By-Layer assembly is employed to form films from hematite nanoparticles and photo-electrochemical responses are observed. Hematite is formed by CVD from a ferrocene precursor in variable thickness on FTO and ITO substrates. The efficiency is improved by a factor of 4 due to higher density. Spray-pyrolysis of hematite is used to study doping effect on efficiency and morphology of its films. Addition of TMS to hematite precursor is investigated and the dramatic effect on the photo-current is discussed. A solid solution SrTi1-xFexO3-y (STF) is studied giving efficiency up to 11%