Structural, opto-electronic and photoelectrochemical properties of tungsten diselenide thin films

Nanocrystalline tungsten diselenide thin films have been deposited on non-conducting glass and stainless steel substrates by chemical methods. Various preparative conditions were optimized for the formation of thin films. The X-ray diffraction analysis shows that the film samples are in layer-hexagonal crystal structure. EDAX analysis shows that the films are nearly stoichiometries of W:Se. Optical properties show a direct band gap nature with band gap energy 1.5 eV. Specific electrical conductivity was found to be in the order of 10−3 to 10−2 (Ω cm)−1. The photoelectrochemical characterization of the films was carried out by studying current–voltage characteristics, capacitance–voltage and power output characteristics. The efficiency of photoelectrode was found to be 1.31 % using iodine–poly iodide electrolyte.