Impedance analysis for dye-sensitized solar cells with a three-electrode system

Impedance analysis for dye-sensitized solar cells was carried out in a three-electrode cell by using a glass vessel to separate the impedances attributable to the working electrode and the counter electrode. When the distance between the working and counter electrodes increased, the overall impedance of the cells was not affected by this parameter, although the solvent resistance and the thickness of the diffusion layer was increased with the distance between the electrodes. Various kinds of Pt counter electrodes were used for impedance measurement with the three-electrode set-up. Counter electrodes of small surface area resulted in a large arc in the impedance spectra of the counter electrodes, whereas the impedance spectra of the TiO2-working electrodes showed no differences when the surface area of the counter electrode was decreased. These results suggested that the impedance measurement using a three-electrode glass vessel type dye-sensitized solar cell was suitable to separate the impedances attributed to the working and counter electrodes.