Enhanced photovoltaic performance of dye-sensitized solar cells based on ZnO microrod array/TiO2 nanoparticle hybrid films

We report in this paper a simple and cheap method for the preparation of ZnO microrod array/TiO2 nanoparticle hybrid films for applications in dye-sensitized solar cells (DSCs), which is achieved by screen printing TiO2 paste into the interspace of low-density ZnO microrod arrays grown on FTO glass. The as-fabricated DSCs exhibit a remarkably enhanced power conversion efficiency of 7.76%, higher than 6.57% for standard TiO2 nanoparticle based DSCs. The electrochemical impedance spectroscopy analysis reveals that the electron transport, electron lifetime, effective diffusion length and the electron collection efficiency are increased, while the charge recombination is reduced, indicating that the ZnO microrod array/TiO2 nanoparticle hybrid film can be considered as a superior material to TiO2 nanoparticle in many respects.