Theoretical modeling of TiO₂/TCO interfacial effect on dye-sensitized solar cell performance

A theoretical model based on an integration of both Schottky barrier model and electron diffusion differential model was developed to determine the TiO2/TCO interfacial effect on the current-voltage (J-V) characteristics of a dye-sensitized solar cell (DSSC). The thermionic-emission theory was appropriately applied to describe the electron transfer at the TiO2/TCO interface. A parametric analysis was conducted to study how the photoelectric outputs varied with multiple independent variables, such as Schottky barrier height ( φb) and temperature. It was found that the variation of the maximum DSSC power output (Pmax) was insignificant when φbvaried at a low value; however, an increase in φbexceeding a critical value caused an apparent decrease in the maximum DSSC power output. The theoretical results were quantitatively compared and agreed very well with published theoretical results. The experimental data from literature were found to agree well with the present theoretical results, qualitatively validating the present model. The theoretical model can be applied to facilitate selection of suitable TCO material in DSSC design to avoid the adverse TiO2/TCO interfacial effect.