Photoelectrochemistry of Culn₁₁S₁₇

Abstract

Polycrystalline samples of Culn₁₁S₁₇ have been prepared by the homogeneous precipitation technique. The electron probe microanalyses (EPMA) have shown the presence of excess sulphur with as-precipitated samples, which has been considerably reduced by subsequent annealing. From the reflectance measurements, the band gap has been determined to be 1.45eV. The photoelectrochemical behaviour of n-Culn₁₁S₁₇ has been studied in different redox electrolytes, namely, polysulphide, polyiodide, and ferro/ferricyanide, and the best photoresponse was observed with the polysulphide redox system. Photoetching in a poly-sulphide electrolyte at a strong anodic bias highly improves the photoresponse of this material. It has also been shown that our n-Culn₁₁S₁₇ photoanode in electrochemical photovoltaic cell has a good stability at working conditions in a polysulphide solution. Finally, the future perspectives of the material have been briefly discussed.