Performance variations and recovery effects in dye sensitized solar cells during long term exposure to natural winter conditions

We report here on performance tests of dye sensitized solar cells in cold outdoor conditions with temperatures down to -30 °C. Two different types of DSSCs: traditional thermally platinized counter electrode and carbon composite counter electrode based dye sensitized solar cells were installed on a vertical window in Finland and exposed for a period of about 3 months. Photovoltaic performance (IV) and electrochemical impedance spectroscopy (EIS) measurements were performed in regular intervals of the cells. Increase in the cell resistance of the DSSCs with thermally platinized counter electrodes significantly affected the fill factor and reduced the efficiency by 12%. The EIS investigations revealed an increase in charge transfer resistance for thermally platinized counter electrodes whereas the carbon composite counter electrode based DSSC exhibited much stable performance and their overall efficiency marginally affected.