Sulfur Versus Nitrogen Coordination in Copper Redox Mediators Influences the Photovoltaic Performance of Dye‐Sensitized Solar Cells

Dye‐Sensitized solar cells have emerged as promising photovoltaic devices due to their low cost and excellent low‐light performance. Two pairs of copper redox mediators were investigated to assess the influence of ligand donor atoms on the device performance. The sulfur‐containing ligand effectively delocalizes electron density around the central metal, thereby enhancing the redox potential and ultimately achieving a high open‐circuit voltage of 1.0 V in the device, together with a power conversion efficiency of 8.62%. This study establishes a novel electrolyte structural engineering strategy for the device performance enhancement.