Enhanced photovoltaic performance of dye-sensitized solar cells using TiO2-decorated ZnO nanorod arrays grown on zinc foil

TiO2-decorated ZnO nanorod arrays directly grown on zinc foil are fabricated by a two-step approach combining hydrothermal oxidation and a sol-gel process for dye-sensitized solar cells (DSSCs) applications. Its dye absorption and light harvesting are increased by decoration with a TiO2 particle layer, resulting in enhancement of the photocurrent density. In addition, the open-circuit voltage (V-OC) of the DSSCs is improved by suppressing interfacial carrier recombination. As a result, the conversion efficiency (eta) of the TiO2-decorated ZnO photoanode is increased by a factor of 1.78 compared with that of the bare ZnO. The electrochemical impedance spectroscopy (EIS) analysis shows that depositing TiO2 particles on the surface of the ZnO nanorod arrays can effectively extend electron lifetime and decrease electron recombination rate. (C) 2011 Elsevier B.V. All rights reserved.