Enhancing the efficiency of ZnO/Cu2O inorganic nanostructure solar cells simply by CdS quantum dots

An enhanced efficiency of ZnO/Cu2O inorganic nanostructure solar cells simply sensitized by CdS quantum dots (QDs) prepared by a chemical bath deposition method has been demonstrated. An appropriate coating of the CdS QDs on the ZnO nanorods leads to a maximum power conversion efficiency (PCE) of 1.53%, which is increased to more than three times compared with the reference device. And a maximum IPCE of 58.1% is obtained at 456 nm with CdS QDs of 9 CBD cycles. The dramatically enhanced PCE is primary resulted from the improvement of the open-circuit voltage and the short-circuit current density, which is attributed to the formation of a cascade structure and increase of the absorbance by the CdS QDs coating. Our finding provides an effective method for the fabrication of the sensitized layer on ZnO, which can pave the way to further improve the efficiency of ZnO/Cu2O inorganic solar cells.