Electron transport properties in ZnO nanowire array/nanoparticle composite dye-sensitized solar cells

A significant improvement of the efficiency of the ZnO nanowire (NW) dye-sensitized solar cell (DSSC) has been achieved by the chemical bath deposition of the dense nanoparticles (NPs) within the interstices of the vertical ZnO-NW anode. Impedance analyses of the electron transports in DSSCs reveal that the effective diffusion coefficient of an electron in the ZnO-NW array/NP composite anode falls between those in the ZnO-NW and TiO2-NP anodes. The superior performance of the ZnO-NW array/NP composite DSSC to the ZnO-NW cell is mainly ascribed to the enrichment of the light harvesting without significantly sacrificing the electron transport efficiency.