Investigation of thermal stability of Dye-sensitized solar cells

Abstract

The dye-sensitized solar cell (DSSC) was assembled and studied for the long - term stability under thermal ageing test at 85^oC. The performances of the DSSCs before the test (fresh cell) and after ageing were characterised under irradiation of intensity of 100 mW/cm² (AM 1.5) using the solar simulator system.  The fresh cell showed an energy conversion efficiency of 8%, a short-circuit current of 17.5 mA/cm², an open-circuit voltage of 0.752 V and a fill factor of 0.62. After ageing at 85^oC for 1,000 hours, the cell performances decreased significantly with an energy conversion efficiency of 0.83%, a short-circuit current of 2.5 mA/cm², an open-circuit voltage of 0.621 V, and a fill factor of 0.535. The electrochemical impedance spectroscopy (EIS) technique was applied to study the degradation mechanism of the cells under thermal ageing test. It was found that the loss of performance of DSSCs after the first thermal ageing in 240 hours was caused by the degradation of photoanode. By increasing the aging time, the performance of DSSCs was degraded by the degradation of the cathode and the electrolyte.