CdS/CdSe Co-sensitized Solar Cells Based on Hierarchically Structured SnO2/TiO2 Hybrid Films

SnO 2 nanosheet-structured films were prepared on a fluorine-doped tin oxide (FTO) substrate using ZnO nanosheet as template. The as-prepared SnO 2 nanosheets contained plenty of nano-voids and were generally vertical to the substrate. TiO 2 nanoparticles were homogeneously deposited into the intervals between the SnO 2 nanosheets to prepare a hierarchically structured SnO 2 /TiO 2 hybrid film. The hybrid films were co-sensitized with CdS and CdSe quantum dots. The sensitized solar cells assembled with the SnO 2 /TiO 2 hybrid film showed much higher photoelectricity conversion efficiency than the cells assembled with pure TiO 2 films. The lifetime of photoinduced electron was also investigated through electrochemical impedance spectroscopy, which showed that the SnO 2 /TiO 2 hybrid film electrode is as long as the TiO 2 film electrode.