Enhancing the Stability of Porphyrin Dye‐Sensitized Solar Cells by Manipulation of Electrolyte Additives

The use of porphyrin‐based photosensitizers with superior light‐harvesting properties has enabled the power conversion efficiency of dye‐sensitized solar cells (DSCs) to reach 13 % under full sun illumination. However, a major limitation of such devices corresponds to the volatility of the solvent used so far for the electrolyte, which prevents practical applications. In this work, we describe a porphyrin‐ionic liquid DSC, which not only affords the highest efficiency reported to date, but is also stable for more than 300 h under continuous full sun illumination at 60 °C. Furthermore, we identify a previously unreported pathway for device degradation, and show that the addition of N ‐methylbenzimidazole and a thiocyanate salt to the electrolyte is critical to obtaining long‐lived devices.