Red phosphorescent iridium(III) complexes containing 2,3-diphenylquinoline derivatives for OLEDs

Abstract

For the application in organic light-emitting diodes (OLEDs), the efficient new red phosphorescent iridium(III) complexes, bis[2,3-diphenyl-4-methyl-quinolinato-C 2,N] iridium(III) acetylacetonate [Ir(4-Me-2,3-dpq) 2(acac)] and bis[2,3-di(4-methoxy-phenyl)-4-methyl-quinolinato-C 2,N] iridium(III) acetylacetonate [Ir(4-Me-2,3-dpq(OMe) 2) 2(acac)] were synthesized from the two-step reactions of IrCl 3· xH 2O with the corresponding ligand. The complexes were characterized by mass spectrometry and 1H NMR. In the photoluminescence (PL) spectra, Ir(4-Me-2,3-dpq) 2(acac) and Ir(4-Me-2,3-dpq(OMe) 2) 2(acac) exhibited the luminescence peak at 604 and 592 nm, respectively. Their electroluminescent (EL) devices with a configuration of ITO/2-TNATA/NPB/CBP:dopant/BCP/AlQ 3/Liq/Al were fabricated. Ir(4-Me-2,3-dpq) 2(acac) and Ir(4-Me-2,3-dpq(OMe) 2) 2(acac) showed the luminous efficiency of 8.10 cd/A and 9.81 cd/A at J of 20 mA/cm 2, respectively. The Commission Internationale de L’Eclairage (CIE) coordinates of Ir(4-Me-2,3-dpq) 2(acac) and Ir(4-Me-2,3-dpq(OMe) 2) 2 (acac) were (0.644, 0.352) and (0.615, 0.375), respectively.