Single emissive layer white phosphorescent organic light-emitting diodes based on solution-processed iridium complexes

We fabricated efficient, white phosphorescent organic light-emitting diodes (WPhOLEDs) with all of blue, yellow, and deep-red iridium(III) complexes doped in 4,4',4 ''-tris(cabazol-9-yl)triphenylamine [or 1,3-bis(carbazol-9-yl)benzene)]: poly(9-vinylcarbazole):1,3-bis[2-(4-tert-butylphenyl)-1,3,4,-oxadiazo-5-yl] mixed-host system and investigated their photophysical, electrochemical, and electroluminescent properties. An optimal combination of blue, yellow, and deep-red iridium(III) complexes improved the charge balance and triplet excitons confinement in the emitting layer. We fabricated the WPhOLEDs with a configuration of indium tin oxide/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (40 nm)/ emitting layer (50-60 nm)/1,3,5-tri[(3-pyridyl)-phen-3-yl]benzene (20 nm)/lithium fluoride (1 nm)/ aluminum (150 nm). In terms of performance, the WPhOLEDs exhibited a maximum luminance efficiency of 23.04 cd/A and external quantum efficiency of 11.45%. (C) 2014 Elsevier Ltd. All rights reserved.