Synthesis of a high-efficiency red phosphorescent emitter for organic light-emitting diodes

Four novel red phosphorescent emitter compounds bis(1-phenylisoquinolinato-N,C-2')iridium(acetylacetonate), (piq)(2)Ir(acac), bis(1-(1'-naphthyl)isoquinolinato-N,C-2') iridium(acetylacetonate), (1-niq)(2)Ir(acac), bis(1-(2'-naphthyl) isoquinolinato-N,C-2') iridium(acetylacetonate), (2-niq)(2)Ir(acac) and bis(1-phenyl-5-methylisoquinolinato-N,C-2')iridium(acetylacetonate), (m-piq)(2)Ir(acac), have been synthesized and fully characterized. Electroluminescent devices with a configuration of ITO/NPB/CBP: dopant/BCP/AlQ(3)/Al were fabricated. All devices emitted in the red region with an emission ranging from 624 to 680 nm. (m-piq)(2)Ir(acac) shows a maximum brightness of 17164 cd m(-2) at a current density of J=300 mA cm(-2) and the best luminance efficiency of 8.91 cd A(-1) at a current density of J=20 mA cm(-2). (1-niq)(2)Ir(acac) exhibits pure-red emission with 1931 CIE (Commission International de L'Eclairage) chromaticity coordinates x=0.701, y=0.273.