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

The halogen bonding between [Ru(dcbpy)(2)(SCN)(2)] dye and I-2 molecule has been studied. The ruthenium complex forms a stable [Ru(dcbpy)(2)(SCN)(2)] center dot center dot center dot I-2 center dot 4(CH3OH) adduct via S ... I interaction between the thiocyanate ligand and the I-2 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-/I-3(-) electrolyte in dye sensitized solar cells.