An organic sensitizer with a fused dithienothiophene unit for efficient and stable dye-sensitized solar cells.

We report a high molar extinction coefficient organic sensitizer for high efficiency dye-sensitized solar cells. In combination with a solvent-free ionic liquid electrolyte, we have demonstrated a approximately 7% cell showing an excellent stability measured under the thermal and light soaking dual stress. This is expected to have an important practical consequence on the production of flexible, low-cost, and lightweight DSC based on plastic matrix.