Effect of Pt distribution in TiO2 films on the photoelectrochemical Behaviors

TiO2 films with Pt distributing in bottom layer(PT) or uniformly(PP) were prepared by a sol-gel method through alternate dip-coating process. The photoelectrochemical behaviors of the films were measured by a three-electrode system, and the dye-sensitized solar cells (DSSC) with these films as anodes were assembled to investigate the photoelectric conversion capacities. The results show that the photocurrent of PT film is higher than that of TT and more enlarged by ethanol addition into the electrolyte as the holes' capture agent. The above phenomena can be explained based on the separation of photogenerated carriers and photoholes' accumulation in the surface layer. Due to photoholes' accumulating in the surface, the excited electrons can transfer to TiO2 film more easily. The short-circuit I-sc and the open-potential V-oc are increased obviously.