Comparison between positive and negative constant current stress on dye-sensitized solar cells

In this work, we performed positive and negative constant current stresses (CCS) on dye-sensitized solar cells in the dark with different polarities. We found that positive and negative CCSs have different effects on DC parameters, featuring different degradation rates, depending on intensity of the stress current. In particular, positive CCS leads to the reduction of tri-iodide concentration in the electrolyte, lowering the dark current of the cell. In addition, from impedance measurements, we found that positive CCSs induce the degradation of the TiO2/Dye/electrolyte interface and negative CCSs induce the degradation of Pt counter-electrode surface. © 2013 Elsevier Ltd. All rights reserved.