Influence of quantum dots and TiO₂ photoanode parameters on electron lifetimes and performance of photonode

Effects of film thickness of P25TiO₂ photoanode, different types of quantum dots sensitized and method of quantum dots co-sensitization, which are the factors of interest, on P25TiO₂ photoanode were analyzed. The relationship between P25TiO₂ film thickness and electron lifetimes were investigated by the method of successive ionic layer absorption and reaction (SILAR). Besides, the influence of quantum dots type and method of quantum dots co-sensitization on photoelectrochemical performance of photoanode was studied. Electrochemical impedance spectra (EIS), open circuit voltage decay (OCVD) and UV-Vis absorption spectra were used to measure and analyze the factors which influence the photoelectrochemical performance and electron lifetimes of P25TiO₂ photoanode. The results indicate that P25TiO₂ with the film thickness of 12 μm exhibits the minimum recombination losses and longer electron lifetimes. Furthermore, the short circuit current and power conversion efficiency of co-sensitized photoanode (TiO₂/CdS/CdSe/ZnS) increase 34% and 42% respectively compared to those of single sensitized photoanode (TiO₂/CdS). Besides, appropriate film thickness of P25TiO₂ photoanode and method of co-sensitization are important factors to increase the electron lifetimes of photoanode, the absorption spectrum and intensity of photoanode.