Influence of surface states of CuInS2 quantum dots in quantum dots sensitized photo-electrodes

Abstract Surface states are significant factor for the enhancement of electrochemical performance in CuInS 2 quantum dot sensitized photo-electrodes. DDT, OLA, MPA, and S 2− ligand capped CuInS 2 quantum dot sensitized photo-electrodes are prepared by thermolysis, solvethermal and ligand-exchange processes, respectively, and their optical properties and photoelectrochemical properties are investigated. The S 2− ligand enhances the UV–vis absorption and electron–hole separation property as well as the excellent charge transfer performance of the photo-electrodes, which is attributed to the fact that the atomic S 2− ligand for the interfacial region of quantum dots may improve the electron transfer rate. These S 2− -capped CuInS 2 quantum dot sensitized photo-electrodes exhibit the excellent photoelectrochemical efficiency and IPCE peak value, which is higher than that of the samples with DDT, OLA and MPA ligands.