Efficient red electrophosphorescent devices based on iridium complexes of fluorinated 1-phenylisoquinoline

Abstract

The iridium complexes containing fluorinated 1-phenylisoquinoline ligands were prepared and their luminescent properties were investigated. Density functional theory (DFT) was applied to calculate the energies of highest occupied molecular orbitals (HOMOs) and lowest unoccupied molecular orbitals (LUMOs) in the iridium complexes. Electroluminescent devices were fabricated with a configuration of indium tin oxide (ITO)/4,4 ',4 ''-tris[2-naphthylphenylainino]triphenylamine (2-TNATA)/4,4 '-bis[N-(naphthyl)-N-phenyl-amino]biphenyl (NPB)/4,4,N,N '-dicarbazolebiphenyl (CBP):dopant/bathocuproine (BCP)/tris-(8-hydroxy-quinoline) aluminum (Alq(3))/lithium quinolate (Liq)/Al. The device using bis[1-(5-fluorophenyl)isoquinolinato-C2,N] iridium acetylacetonate [Ir(5-Fpiq)(2)(acac)] as a dopant showed red emission with 1931 Commission Internationale de I'Eclairage (CIE) chromaticity coordinates (x = 0.68, y = 0.30). Organic light-emitting device (OLED) based on bis[1-(4,5-difluorophenyl)isoquinolinato-C-2,N] iridium(III) acetylacetonate [Ir(4,5-F(2)piq)(2)(acac)] yielded luminous efficiency of 9.9 cd/A at a luminance of 11840 cd/m(2).