Dependence of Dye-Sensitized Solar Cell Impedance on Photoelectrode Thickness

Dye-sensitized solar cells with a wide range of porous TiO 2 layer thicknesses ( d = 3–18 μm) have been characterized by impedance spectroscopy. Spectra were analyzed using a well-known equivalent circuit model incorporating a transmission line to obtain the distributed resistance and capacitance parameters characterizing the TiO 2 layers. No significant dependence on d was found for any of the distributed parameters, reaffirming the validity of this commonly used model. Other elements in the equivalent circuit model which represent the substrate/electrolyte, cathode/electrolyte, and FTO/TiO 2 interfaces are also examined and discussed.