or [Ru(bpy)₃]²⁺), the lifetime of the triplet excited state is approximately 1100 ns. This lifetime is sufficient for other relaxation pathways (specifically, electron-transfer pathways) to occur before decay of the catalyst to its ground state.

The long-lived triplet excited state accessible by photoexcitation is both a more potent reducing agent and a more potent oxidizing agent than the ground state of the catalyst. Since sensitizer