ZnO nanosheets decorated with CdSe and TiO ₂ for the architecture of dye-sensitized solar cells

Pure and TiO ₂- and CdSe-deposited ZnO nanosheets aligned vertically to the surface of ITO (Indium tin oxide) are prepared using electrodeposition, which is used for building blocks of dye sensitized solar cell. A significant improvement in the photovoltaic efficiency can be obtained by depositing TiO ₂ or CdSe on ZnO. Photoluminescence spectra show that the TiO ₂ and CdSe nanostructures suppress the recombination of the electron-hole pair of ZnO. We suggest that the interface charge transfer at TiO ₂-ZnO and CdSe-ZnO should be responsible for the suppression of the electron-hole pair recombination and enhanced solar cell efficiency by TiO ₂ and CdSe nanostructures.