Dye-sensitized solar cell performance and photocatalytic activity enhancement using binary zinc oxide-copper oxide nanocomposites prepared via co-precipitation route

Zinc oxide nanoparticles (ZnO NPs) and binary ZnO–CuO nanocomposites (ZnO–CuO NCs) were prepared through a simple chemical co-precipitation route. The influence of copper (Cu²⁺) ions concentration (0.03, 0.06, 0.09, and 0.12 M) on optical, morphological, structural, and elemental characteristics of the ZnO–CuO NCs was examined by appropriate characterization techniques. The visible light reactive CuO created absorption shift to red region that minimized band gap of the ZnO–CuO NCs. The concentration of Cu²⁺ ions produced appreciable impact on size of the ZnO–CuO NCs. The dye-sensitized solar cell (DSSC) constructed using ZnO–CuO NC photoanode with Cu²⁺ ions concentration of 0.06 M generated a conclusive solar to electrical energy transformation efficiency of 2.56%, which was a 2.2-times greater over the DSSC encompassed pristine photoanode of ZnO NPs. The electrochemical impedance spectroscopy analysis revealed the longer lifetime of the photogenerated electrons and reduction in the charge recombination rate in the ZnO_(0.44)–Cu_(0.06) NC photoanode based DSSC. Furthermore, the ZnO_(0.44)–Cu_(0.06) NC disclosed substantial photocatalytic activity towards methylene blue dye degradation that could be chiefly credited to its particles size induced visible light absorption property.