Cu-doping ZnO/ZnS nanorods serve as the photoanode to enhance photocurrent and conversion efficiency

Cu-doped ZnO/ZnS (Cu/ZnO/ZnS) nanorods were prepared via sol–gel and hydrothermal deposition routes. The target product can serve as the photoanode of the dye-sensitized solar cells. Four nanostructures (ZnO, Cu/ZnO, ZnO/ZnS and Cu/ZnO/ZnS nanorods) were successfully synthesized and characterized. For the Cu/ZnO/ZnS structure, both the Cu-doping and ZnS coating can enhance photocurrent and conversion efficiency compared with the bare ZnO nanorods. The promoting effect of the Cu-doping on the photoanode could be attributed to the formation of intermediate energy level that allows Cu/ZnO to be activated easily in the visible area. The ZnS compact layer retards the back transfer of electrons to the dye and electrolyte, decreasing the composite of them and increasing the final photocurrent. Hence, the Cu/ZnO/ZnS one obtains the maximum efficiency 1.40%, and the Jsc and Voc were 5.7 mA cm−2 and 631 mV, respectively.

The schematic diagrams of N3/ZnO and N3/Cu/ZnO/ZnS photoelectrodes (a) and the stepwise band edge structure of N3/Cu/ZnO/ZnS photoelectrode (b).Figure optionsDownload as PowerPoint slideHighlights
► Cu-doped ZnO/ZnS nanorods as photoanode of DSSCs.
► Cu/ZnO/ZnS by sol–gel and hydrothermal deposition routes.
► High cell efficiency of Cu/ZnO/ZnS mainly due to the Cu doping and shell structure.