Intriguing Photochemistry of the Additives in the Dye-Sensitized Solar Cells

Over the years numerous mixes of chemical compounds have been tried in the electrolytes of dye-sensitized solar cells in efforts to improve their efficiency. How these chemicals interact with each other and the photoelectrode has received surprisingly little attention. Here we report results from a systematic study of two I–/I3– electrolytes and their additives using infrared and Raman spectroscopy together with quantum chemical calculations. In the LiI electrolyte competing interactions between lithium cation and the solvent MPN and the additives TBP, NMBI, and GuSCN were identified. These interactions could inhibit the interaction of lithium ions with the TiO2 surface. It was found that u…