Long-term stability of organic–dye-sensitized solar cells based on an alkyl-functionalized carbazole dye

We investigated the long-term stability of performance for dye-sensitized solar cells (DSSCs) based on an alkyl-functionalized carbazole dye (MK-2) and used in conjunction with ionic liquid-based electrolytes. We observed good long-term stability of the performance of the DSSCs during 60 days under visible-light irradiation at ca. 50 °C. The performance of the DSSC decreased gradually under white-light irradiation including UV light or at 80 °C under dark conditions. However, no decomposition or detachment of the dye molecule from the TiO2electrode was observed after these measurements. These results indicate that the MK-2dye molecule in the cell was stable even under white-light irradiation and at 80 °C under dark conditions.