ABSTRACT:

In this paper, we study the reliability of sensitized solar cells. We carried out accelerated illumination stresses with the purpose to extract a degradation law as a function of time, illumination intensity, and temperature in order to understand which are the most important mechanisms involved in the degradation. The main responsible for degradation during illumination stresses is the formation of defects and chemical species at TiO $_2$/sensitizer/electrolyte interface, which reduces the charge transfer at the interface and the ion migration across the electrolyte. Since the sunlight exposure increases the temperature of the dye-sensitized solar cell (DSC), we have studied the role of temperature on the degradation of DSCs by pure thermal stresses. We found that temperature alone strongly impacts the DSC performance, enhancing the degradation of the sensitizer and then reducing the photogenerated current.