Red-phosphorescent OLEDs employing iridium (III) complexes based on 5-benzoyl-2-phenylpyridine derivatives

Abstract

A series of red-phosphorescent iridium (III) complexes 1-4 based on 5-benzoyl-2-phenylpyridine derivatives was synthesized. Their photophysical and electrophosphorescent properties were investigated. Multilayered OLEDs were fabricated with a device structure ITO/4,4',4 ''-tris(N-(naphtalen-2-yl)-N-phenylamino)triphenylamine (60 nm)/4,4'-bis(N-naphtylphenylamino)biphenyl (20 nm)/Ir(III) complexes (8%) doped in 4,4'-N,N'-dicarbazolebiphenyl (30 nm)/2,9-Dimethyl-4,7-diphenyl-1,10-phenanthroline (10 nm)/tris(8-hydroxyquinolinyl)aluminum(III) (20 nm)/Liq (2 nm)/Al (100 nm). All devices exhibited efficient red emissions. Among those, in a device containing iridium complex 1 dopant, the maximum luminance was 14200 cd/m(2) at 14.0 V. Also, its luminous, power, and quantum efficiency were 10.40 cd/A, 3.44 lm/W and 9.21% at 20 mA/cm(2), respectively. The peak wavelength of the electroluminescence was 607 nm, with CIE coordinates of (0.615, 0.383) at 12.0 V. and the device also showed a stable color chromaticity with various voltages. (C) 2010 Elsevier B.V. All rights reserved.