Phenylpyrimidine-Based Iridium Complex for High-Performance Green-Yellow Phosphorescent Organic Light-Emitting Diodes

Abstract In this work, a phenylpyrimidine-based green-yellow iridium complex, (bpp) 2 Ir(acac), is prepared. Tert-butyl group is introduced to weaken the intermolecular interaction and endow (bpp) 2 Ir(acac) with favorable physical properties. Phosphorescent device which utilizes (bpp) 2 Ir(acac) as the luminescent guest material displays high efficiencies (73.9 cd/A, 84.8 lm/W, 21.2%), low efficiency roll-off (from 100 to 10000 cd/m 2 : 5.1%), relatively low concentration sensitivity (from 5% to 12%) and very stable electroluminescent spectra (from 1 cd/m 2 to maximum luminance). As a consequence of the results proved that (bpp) 2 Ir(acac) is a good phosphorescent material.