Oxide Thickness and Roughness Factor as Parameters for TiO2-Dye Sensitized Solar Cells Performance

Oxide surface roughness in connection to oxide thickness has proved to be a key parameter for the performance of a dye sensitised solar cell. In this work, the numerical simulation of the system TiO2-photo sensitive dye of a dye sensitized TiO2 solar cell focuses on these two parameters. The steady-state numerical model used is based on the continuity and transport equations for charge species involved in the system, in connection to Poisson's equation. Light absorbance is set dependent upon TiO2 porosity and resulting electron density after illumination is derived as a function of the illuminating beam characteristics and material properties. Electron lifetime in the bulk is set dependent upon electron distribution with electron lifetime at the surface taking into consideration surface recombination. An effective dielectric constant dependent also upon the porosity of TiO2 is used in the model. Results for different values of the TiO2 thickness and surface roughness leading to optimum values for the cell performance are found in accordance with results reported in the literature.