Modeling trap assisted recombination in Dye Sensitized Solar Cells

Despite the evidences on the significance of TiO2/dye/electrolyte interface states on the performance of Dye Sensitized Solar Cell (DSSC), no previous model has incorporated interfacial trap-assisted charge transfer processes to model recombination rate in DSSCs. A new charge transport model for DSSC is presented in this paper based on physics of electron capture, electron emission, oxidation and reduction processes mediated by the deep interfacial trap states. The model suggests that recombination in DSSC is due to trapping of conduction band electrons by deep defect states followed by reduction process at the interface. The model has been investigated through simulated quantum efficiency, dark and illuminated IV characteristics. The simulated results based on this model are in good accord with the experimental results.