Hydrothermal synthesis of ZnO materials for a dye-sensitized solar cell

In this work, the morphology of ZnO materials is controlled by changing the capping agents at a constant alkali solution in hydrothermal process. ZnO nanomaterials with the structure of flowers, sheet-spheres and plates are obtained with the capping agent of ammonia, citric acid and oxalic acid, respectively. Thus prepared ZnO nanomaterials are characterized and applied as the photoanode materials for dye-sensitized solar cell. All synthesized ZnO nanomaterials possess high crystalline wurtzite structures grown in the (0 0 1) direction with the size of 2-4µ m, which consist of ZnO units around 20-400 nm. Among them, sheet-sphere ZnO shows the highest crystallinity, surface area and uniform film morphology, resulting in the significantly improved PV performance with the overall conversion efficiency of ~2.61% in dye-sensitized solar cell (DSSC) fabricated with sheet-sphere ZnO. It is notable that the ZnO materials with sphere structure might be the optimal photo-anode material among various ZnO nanomaterials for DSSC.