▎ 摘　　要

In this study, graphene/TiO2 composite films at different annealing temperatures from 450 to 650 degrees C acted as photo-electrode of dye-sensitized solar cell (DSSC). The graphene/TiO2 composite films were characterized by scanning electronic microscopy, X-ray diffractometer, and electrochemical impedance spectroscopy. The Nyquist plot is built to simulate the redox reaction of internal device at the heterojunction by an equivalent circuit model. It is useful to analyze the component structure and promote photovoltaic conversion efficiency of DSSC. According to the experiment results, the optimal annealing temperature of graphene/TiO2 composite film was 550 degrees C, where the open-circuit voltage was 0.74 +/- 0.01 V, the short-circuit current density was 14.17 +/- 0.32 mA/cm(2), the fill factor was 51.00 +/- 1.95%, and the photovoltaic conversion efficiency was 5.34 +/- 0.12%.