Zusammenfassung
The lowest triplet state T₁ of Ir(btp)₂(acac) doped into CH₂Cl₂ is studied by site-selective and time-resolving emission and by excitation spectroscopy at cryogenic temperatures. Different sites due to different environments of Ir(btp)₂(acac) show dissimilar intensity
distributions of the substate emissions, zero-field splittings, emission decay times, and spin-lattice relaxation (SLR) times. ...
Zusammenfassung
The lowest triplet state T₁ of Ir(btp)₂(acac) doped into CH₂Cl₂ is studied by site-selective and time-resolving emission and by excitation spectroscopy at cryogenic temperatures. Different sites due to different environments of Ir(btp)₂(acac) show dissimilar intensity
distributions of the substate emissions, zero-field splittings, emission decay times, and spin-lattice relaxation (SLR) times. Temperature dependent investigations of the SLR processes reveal the importance of the direct process and the Orbach process. Moreover, the emitting T₁ state is assigned as ³LC (ligand-centered) state with significant ¹,³MLCT (metal-to-ligand charge transfer) perturbation. This classification is related to the usability of phosphorescent emitters in OLEDs.