Photoelectrochemical Energy Conversion Obtained with Ultrathin Organo‐Metallic‐Chemical‐Vapor‐Deposition Layer of FeS2 (Pyrite) on TiO2

Ultrathin (10 to 20 nm thick), polycrystalline films of (pyrite) were grown on (anatase) by chemical vapor deposition. The films were characterized using optical absorption and high‐resolution electron microscopy. Photoelectrochemical solar cells, using (anatase) coated with ultrathin films, generated high open‐circuit photovoltages, of up to 600 mV, compared with a single crystal of pyrite electrode (200 mV). The photoelectrochemical behavior shows a strong dependence of photovoltage and photocurrent on the pH of the solution. It is explained by electron injection from the conduction band of to the conduction band of . Regeneration of holes is taking place by electron transfer from the redox system in the electrolyte.