Predicting phosphorescent rates of Ir(III) complexes

The theoretical luminescence efficiency of fluorescent-only organic light-emitting diodes (OLEDs) can be increased from 25% to 100% by harvesting triplet excitons with transition metal complexes, most notably Ir(III).

In a recent J. Phys. Chem. C paper, Jarod Younker and Kerwin Dobbs present a pragmatic approach to predict photophysical properties of such phosphorescent emitters used in OLED devices. For emission lines and radiative rates, the best correlation with experiment is obtained when using perturbative spin-orbit coupled TDB3LYP at the BP86 optimized S0 geometries. This protocol can be used as a first virtual screening for new phosphorescent OLED materials. SOC-TDDFT predicts phosphorescent lifetimes for OLED phosphors

Left: correlation between calculated (SOC-TDDFT) and experimental emission rates. Right: Ir(ppy)3 LUMO.

See also: walk-through example OLED phosphorescent lifetimes with spin-orbit coupling TDDFT

SOC-TDDFT, ZORA

J. M. Younker and K. D. Dobbs, Correlating Experimental Photophysical Properties of Iridium(III) Complexes to Spin−Orbit Coupled TDDFT Predictions, J. Phys. Chem. C, 117, 25714-25723 (2013)

Key concepts