Dye-sensitized solar cell redox shuttles

In this Perspective article we describe how the processes involving the redox shuttle—dye regeneration, recombination, and diffusion—affect the photovoltaic performance of dye-sensitized solar cells, DSSCs. Key literature on the mechanistically complicated, but ubiquitously employed, triiodide/iodide electrolyte is reviewed. Literature examples and recent results from our laboratory in utilizing one-electron outersphere redox shuttles in place of triiodide/iodide are then presented.