The thickness of TiO2 film is vital to realize the optimization on photovoltaic performance of dye sensitized solar cells （DSSCs）. Herein, the process of charge separation in DSSCs was simulated by using a drift-dif...The thickness of TiO2 film is vital to realize the optimization on photovoltaic performance of dye sensitized solar cells （DSSCs）. Herein, the process of charge separation in DSSCs was simulated by using a drift-diffusion model. This model allows multiple-trapping diffu- sion of photo-generated electrons, as well as the back reaction with the electron acceptors in electrolyte, to be mimicked in both steady and non-steady states. Numerical results on current-voltage characteristics allow power conversion efficiency to be maximized by varying the thickness of TiO2 film. Charge collection efficiency is shown to decrease with film thick- ness, whereas the flux of electron injection benefits from the film thickening. The output of photocurrent is actually impacted by the two factors. Furthermore, recombination rate constant is found to affect the optimized film thickness remarkably. Thicker TiO2 film is suitable to the DSSCs in which back reaction is suppressed sufficiently. On the contrary, the DSSCs with the redox couple showing fast electron interception require thinner film to alleviate the charge loss via recombination. At open circuit, electron density is found to decrease with film thickness, which engenders not only the reduction of photovoltage but also the increase of electron lifetime.展开更多
文摘The thickness of TiO2 film is vital to realize the optimization on photovoltaic performance of dye sensitized solar cells （DSSCs）. Herein, the process of charge separation in DSSCs was simulated by using a drift-diffusion model. This model allows multiple-trapping diffu- sion of photo-generated electrons, as well as the back reaction with the electron acceptors in electrolyte, to be mimicked in both steady and non-steady states. Numerical results on current-voltage characteristics allow power conversion efficiency to be maximized by varying the thickness of TiO2 film. Charge collection efficiency is shown to decrease with film thick- ness, whereas the flux of electron injection benefits from the film thickening. The output of photocurrent is actually impacted by the two factors. Furthermore, recombination rate constant is found to affect the optimized film thickness remarkably. Thicker TiO2 film is suitable to the DSSCs in which back reaction is suppressed sufficiently. On the contrary, the DSSCs with the redox couple showing fast electron interception require thinner film to alleviate the charge loss via recombination. At open circuit, electron density is found to decrease with film thickness, which engenders not only the reduction of photovoltage but also the increase of electron lifetime.
