Improved performance induced by in situ ligand exchange reactions of copper bipyridyl redox couples in dye-sensitized solar cells

Copper bipyridyl redox couples are intresting mediators for dye-sensitized solar cells (DSSCs). Here we show that the electrolyte additive 4-tert-butylpyridine (TBP) actually substitutes common bidentate ligands on the Cu(ii) species to form [Cu(TBP)4]2+, which is a poor electron acceptor and thus allows high voltages and charge collection efficiencies to be achieved.