Interface connection modulation by CuxS buffer layer on charge transfer performance enhancement of CuInS2 quantum dot-sensitized solar cells

CuxS thin films are employed as a buffer layer between TiO2 electronic layer and CuInS2 optical absorption layer for the TiO2/CuInS2 quantum dot-sensitized solar cells, which are anticipated to improve the interface connection of the photoelectrodes. The optical absorption spectra and photoluminescence spectra of different photoelectrodes are investigated, which have exhibited the improvement on the optical absorption and charge separation properties of the TiO2/CuInS2-based photoelectrodes under CuxS buffer layer. The influence on the thickness of CuxS buffer layer is also optimized to obtain an excellent interface connection in the solar cells system. And the TiO2/CuInS2 quantum dot-sensitized solar cells obtain better charge transfer property by the introduction of CuxS buffer layer, which can effectively increase the open-circuit voltage and short-circuit current density values of the solar cells, achieving photovoltaic conversion efficiency enhancement from 2.57 to 3.06%.