ZnO/Nb2O5 core/shell nanorod array photoanode for dye-sensitized solar cells

In this paper, ZnO/Nb2O5 core/shell nanorod arrays were synthesized and used as photoanodes for dye-sensitized solar cells (DSSCs). We first synthesized ZnO nanorod array on fluorine-doped tin oxide (FTO) glasses by a hydrothermal method, and then ZnO/Nb2O5 core/shell nanorod array was directly obtained via solvothermal reaction in NbCl5 solution. The scanning electron microscope (SEM) and transmission electron microscope (TEM) images revealed that the ZnO nanorods were uniformly wrapped by Nb2O5 shell layers with a thickness of 30–40 nm. Photovoltaic characterization showed that the device based on ZnO/Nb2O5 core/shell nanorod photoanode exhibited an improved efficiency of 1.995%, which was much higher than the efficiency of 0.856% for the DSSC based on bare ZnO nanorod photoanode. This proved that the photovoltaic performance of ZnO nanorods could be improved by wrapping with Nb2O5 shells.