Long-term stability testing of dye-sensitized solar cells

Abstract This study comprises the behavior of dye-sensitized nanocrystalline TiO 2 solar cells (nc-DSC) under various testing conditions regarding accelerated aging. nc-DSCs are potentially vulnerable to various kinds of degradation. The cell performance is seriously decreased upon heat treatments, despite the fact that leakage of the electrolyte liquid is effectively prevented. Even when cells are stored in the dark at elevated temperatures, apparently side reactions occur, resulting in cell degradation. Since elevated temperatures are hard to exclude under normal operation conditions, this is the most critical criterion regarding long-term stability. The nc-DSC should be modified in such a way that it is not sensitive to elevated temperatures, representative for outdoor conditions. The emphasis of this paper is on the long-term stability of nc-DSCs at high temperature. nc-DSCs have been subjected to various aging tests. A cyclic test comprising thermal stress in the dark (85 °C) alternated by full sun illumination under milder conditions reveals a recovery process occurring in degraded cells. A combination of 85 °C and full sun illumination leads to a significant decrease of the cell performance.