Highly-Efficient Phosphorescent Organic Light-Emitting Diodes with Horizontal Oriented Iridium(III) Complexes

The synthesized green iridium(III) complex dopants with ancillary ligands of homoleptic or heteroleptic structure were characterized. The green phosphorescent OLEDs with 2,2’,6,6’-tetramethylheptanedionate (tmd) dopant exhibit higher device efficiencies of 20.9 %, 77.8 cd/A, 69.8 lm/W than that of the conventional Ir(ppy)3 emitter of 17.6 %, 60.2 cd/A, 52.6 lm/W. The high efficiency OLEDs containing tmd ligand can be explained due to preferred dipole orientation in horizontal direction which shows the relatively strong intensity at χ=0 and narrow azimuthal intensity distribution in 2D-GIWAXD. This research supported by NRF-2019R1I1A1A01064203 of Korea grant.2