Efficient blue organic light-emitting diodes based on an oligoquinoline

An oligoquinoline 6,6′-bis(2,4-diphenylquinoline), with excellent thermal stability and a high glass transition temperature (Tg=133°C), was used as a blue-emitting and electron-transport material to achieve efficient blue electroluminescence. The diodes based on poly(N-vinylcarbazole) hole-transport layer and LiF∕Al cathode had a stable blue emission with a peak at 453nm, chromaticity coordinates at (0.15, 0.12), and a maximum brightness of 925cd∕m2 in air. The external quantum efficiency of 4.1% and luminous efficiency of 3.33cd∕A at 100cd∕m2 are comparable to the best blue organic light-emitting diodes (OLEDs) in the literature. These results demonstrate that oligoquinolines are promising as both blue emitters and electron-transport materials for developing high-efficiency OLEDs with a simpler architecture.