Electrochemical impedance spectroscopy analysis on the dye-sensitized solar cell with different TiO₂ thicknesses

Dye-sensitized solar cell(DSC) is composed of a dye-adsorbed nanoporous TiO₂ layer on fluorine-doped tin oxide(FTO) glass substrate, electrolyte, and platinium doped counter electrode. Among these, a dye-absorbed nanoporous TiO₂ layer plays an important role in the performance of the DSC because the injected electrons from excited dye molecules move through this layer. And the condition of TiO₂ layer such as the morphology and thickness affects on the electron movement. Therefore, the performances and the efficiency of DSC change as the thickness of TiO₂ layer is different. Electrochemical Impedance Spectroscopy(EIS) is the powerful analysis method to study the kinetics of electrochemical and photoelectrochemical processes occurring in the DSC especially the injected electron movements. So we analyzed the DSCs with different TiO₂ thicknesses by using EIS to understand the influence of the TiO₂ thickness to the performance of the DSC clearly. Finally, we got the EIS analysis on the DSC with different TiO₂ thickness from the internal resistance of the DSC, the electron life time and the amount of dye molecules.