The fabrication of TiO2 nanoparticle/ZnO nanowire arrays bi-filmed photoanode and their effect on dye-sensitized solar cells

Porous TiO2 nanoparticles coated on ZnO nanowire arrays(TiO2 NP/ZnO NW) as photoanode for dye-sensitized solar cell(DSSC) has been fabricated and investigated to improve the power conversion efficiency. The TiO2 NP/ZnO NW photoanode consists of single crystalline ZnO NWs synthesized via hydrothermal method and porous TiO2 NP film covered on the surface of ZnO NW arrays by screen printing technique. The effect of TiO2 NPs thickness of the bi-filmed photoanode on the cell performance has been investigated, and TiO2 NP/ZnO NW DSSC with NP thickness of~5μm exhibits the best efficiency of4.68%, higher than1.16% of ZnO NW DSSC and3.18% of TiO2 NPs DSSC, prepared and tested under identical conditions. The efficiency increase is attributed to the enlarged photocurrent, due to the greatly enhanced surface area for dye absorption and light harvesting efficiency resulted from TiO2 NPs, and improved open-circuit voltage, due to reduced electron recombination by providing direct conduction pathway along ZnO NWs.?2011 Springer Science+Business Media, LLC