Interface connection modulation by heating treatment for photovoltaic performance enhancement on CuInS2 quantum dot sensitized solar cells

TiO2/CuInS2 quantum dot sensitized solar cells are prepared, and the interface connection of photo-electrodes is modulated by different heating temperature and heating time. The crystal structures and morphologies of the TiO2/CuInS2 photo-electrodes have been analyzed, which has exhibited slight size growth of QDs. And the optical absorption edges have gradually expanded with the increasing of heating temperature and heating time, which have no obvious changes on optical absorption intensity of TiO2/CuInS2 photo-electrodes. The surface states of QDs and interface connection between CuInS2 QDs and TiO2 films have been optimized, which have exhibited excellent charge separation and charge transfer properties with the heating treatment at 300 °C for 5 min. With the improvement on the interface connection of the solar cells, the photovoltaic conversion efficiency of the TiO2/CuInS2 quantum dot sensitize solar cells have been enhanced from 4.04% to 4.68%.