An analytical study of the porosity effect on dye-sensitized solar cell performance

The porosity in a dye-sensitized solar cell (DSSC) can affect light absorption and electron diffusion that govern the overall electrical current-voltage (I-V) characteristics. In this research, two methods, namely, constant overlap and variable overlap, were developed to determine the connectivity of dye-sensitized TiO2particles in high and low porosity levels, respectively. In turn, the light absorption coefficient α and the electron diffusion coefficient D were analytically derived in terms of the porosity P. Subsequently, the electron diffusion differential equation involving α and D was solved for the I-V output as a function of P. A parametric analysis showed that the optimal porosity was equal to 0.41 for maximum I-V output. The analytical results agree well with experimental data reported in the literature. Besides DSSC, the analytical model can be applied to predict the performance of solid-state DSSC as well as dye-sensitized photoelectrochemical cells applied to hydrogen production and water purification.