Halogen bonding—a key step in charge recombination of the dye-sensitized solar cell

Abstract
The halogen bonding between [Ru(dcbpy)2(SCN)2] dye and I2 molecule has been studied. The ruthenium complex forms a stable [Ru(dcbpy)2(SCN)2]⋯I2·4(CH3OH) adduct via S⋯I interaction between the thiocyanate ligand and the I2 molecule. The adduct can be seen as a model for one of the key intermediates in the regeneration cycle of the oxidized dye by the I/I3 electrolyte in dye sensitized solar cells.