Preparation And Properties Of CuInS₂-Graphene Hybrid Materials

CuInS2 is a new type semiconductor photocatalyst, however, the photogenerated electrons-holes are unstable and can easily recombine, and its light response range is not wide enough, which greatly limits its application in real life. Therefore, reducing the photogenerated electron-hole recombination rate and broaden the range of the optical response of CuInS2 become the main research directions in the field of photocatalysis. Graphene provides the possibility to solve the above problems due to having special optical and electrical properties.In this study, CuInS2 thin films were prepared by one-step potentiostatic electrodeposition. The solution used is dimethyl sulfoxide aqueous solution which includes cuprous chloride, indium chloride, sulfur powder. Base on this system, we were investigated deposition potential, deposition time and the effect of annealing treatment on CuInS2 thin films structure and photoelectric properties. The experiment results proved that, we obtain chalcopyrite CuInS2 thin films which surface smooth and compact-structure under the deposition potential of-1.3V, deposition time of 30min and annealing at 200℃ for 30min, the CuInS2 is a P-type semiconductor material. The method of one-step potentiostatic electrodeposition has the advantages of simple operation, low manufacturing cost.In this paper, we use one-step potentiostatic electrodeposition to prepare CuInS2-graphene hybrid thin films, graphene oxide is reduced while CuInS2 thin film is prepared. The experiment results show that, CuInS2-graphene hybrid thin films could be prepared when the concentration of graphene oxide is 0.2mg/mL, deposition time is 30min. Compared with CuInS2 thin films, CuInS2-graphene hybrid thin films absorption edge red shift, band gap narrowing, and its photoelectric conversion efficiency is obviously improved.Using the CuInS2-graphene hybrid film material as cathode illuminated by sunlight light, to investigate photoelectrocatalytic reduction of CO2. The experiment results proved that, applied bias potential at-0.59V, pH=5.2, the concentration of pyridine is 10mmol/L, the amount of methanol is 0.89mmol/L. Compared with CuInS2 thin film, the methanol production increased by 42.8%.