Efficient blue organic light-emitting diodes based on an oligoquinoline

An oligoquinoline 6,$6^{\prime }$ -bis(2,4-diphenylquinoline), with excellent thermal stability and a high glass transition temperature $(T_g=133°\mathrm{C})$ , 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 $\mathrm{Li}\mathrm{F}∕\mathrm{Al}$ cathode had a stable blue emission with a peak at $453\mathrm{nm}$ , chromaticity coordinates at (0.15, 0.12), and a maximum brightness of $925\mathrm{cd}∕{\mathrm{m}}^2$ in air. The external quantum efficiency of 4.1% and luminous efficiency of $3.33\mathrm{cd}∕\mathrm{A}$ at $100\mathrm{cd}∕{\mathrm{m}}^2$ 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.