The origin of phosphorescence in Iridium (III) complexes. The role of relativistic effects

A series of luminescent Ir(III) complexes of the type [Ir(F2ppy)2L] (where L = Lpytz, LOMe, Lbut) have been studied using relativistic two-component density functional theory (DFT). The three complexes show phosphorescent properties due to a MLCT process, where the SOC plays a key role due to the introduction of a ZFS and the mixing of states with different spins which contributes to modify the emission selection rule.46