Perovskite-sensitized nanoporous TiO2 films with different thicknesses are prepared by an in situ method, which are employed as photoanodes in perovskite solar cells (PSCs). The photoelectrochemical properties of different photoanodes are quantified by the ultraviolet to visible reflectance spectra, incident monochromatic photon-to-current conversion efficiency, and electrochemical impedance spectroscopy measurements. Results demonstrate that the thin photoanode has high electron lifetime for recombination, which can enhance the separation and transmission of the electron and hole. However, the sunlight utilization will decrease with reducing the photoanode thickness due to the small quantity of CH3NH3PbI3 filled into the photoanode to absorb sunlight. After optimization, PSC with 0.80 mu m of the photoanode thickness shows a superior cell efficiency of 12.22% without a hole transporting material. (C) 2015 Elsevier B.V. All rights reserved.