Using the voids. Evidence for an antenna effect in dye-sensitized mesoporous TiO2 thin films

Composite structures of Ru(bpy)(2)(4,4'-(PO(3)H(2))(2)bpy)(2+) surface bound to nanocrystalline TiO(2) with an overlayer of Ru(bpy)(3)(2+) ion exchanged into Nafion, FTO|nanoTiO(2)-[Ru(bpy)(2)(4,4'-(PO(3)H(2))(2)bpy)](2+)/Nafion,Ru(bpy)(3)(2+) (FTO = fluorine-doped tin oxide), have been prepared and characterized. Steady-state emission and time-resolved lifetime measurements demonstrate that energy transfer occurs from Nafion,Ru(bpy)(3)(2+*) to adsorbed Ru(bpy)(2)(4,4'-(PO(3)H(2))(2)bpy)(2+) with an efficiency of ∼0.49. Energy transfer sensitizes photoinjection by the adsorbed metal-to-ligand charge transfer (MLCT) excited state by an "antenna effect."