Using EIS for diagnosis of dye-sensitized solar cells performance

During the last decade interest in dye-sensitized solar cells (DSC) has grown enormously. Electrical impedance spectroscopy (EIS) is an electrochemical technique commonly used for investigation of charge carrier dynamics in these photovoltaic devices. We used EIS for characterization of our DSC; moreover, symmetric cells with counter–counter or photo–photo electrodes were realized and measured in order to simplify impedance cell analysis by separating the contribution of counter and photoelectrode, respectively. In particular, we provided very accurate illumination of the photoelectrode symmetric cell, aiming to approach the experimental conditions of a complete cell. By fitting of experimental data, we obtained values for the charge transfer resistance at the counterelectrode and the electron percolation time at the photoelectrode. Moreover, the simulation of a whole cell, combining the data from the fitting procedures above, was in good agreement with experimental data.