Diffusion of electron density in dye-sensitized solar cells

Dye-sensitized solar cells (DSSCs) are an alternative low-cost solution to the renewable energy problem due to the use of TiO2 as a semiconductor. Electricity generation is achieved through a series of chemical reactions designed to transport excited electrons from photosensitive dyes as a means of creating a circuit. Current modelling approach is based on the diffusion of the density of electrons in the conduction band of a DSSC’s nanoporous semiconductor. In this paper, we review current models for DSSCs based on diffusion equations combining the generation and the loss of the electron density as a result of dye excitation due to sunlight and electron recombination, respectively. Further, we consider another model based on fractional diffusion equation, taking into consideration random porous network of the semiconductor TiO2.