Nanoblocky TiO2 with different contents of Au doping was synthesized by two. step method. Cyclic voltammetry and electrochemical impedance spectroscopy were used to investigate the influence of Au doping on the number and distribution of surface states in the films. Meanwhile, intensity. modulated photocurrent/ photovoltage spectroscopy was used to study the electron transfer and recombination process. The results show that Au doping can effectively reduce the surface states in TiO2 films and optimize the energy distribution. Furthermore, in. depth characterizations indicate that Au doping( molar fraction, 0.2%) can increase the charge transfer resistance at the interfaces of dyed. TiO2/electrolyte. Overall, the cell performance was relatively dependent on the effect of surface states essentially.