High efficiency blue phosphorescent organic light-emitting diodes using 2-(1H-pyrazol-1-yl)pyridin-3-ol ligand based Be compound

• High quantum efficiency of 22.0% in blue phosphorescent organic light-emitting diodes.
• High triplet energy of 2.89 eV for energy transfer to blue dopant.
• Be complex as a host for blue phosphorescent organic light-emitting diodes.

An organometallic complex based on Be and pyridinepyrazole type ligand, bis(2-(1H-pyrazol-1-yl)pyridin-3-olate) beryllium (BePyPy), was synthesized as an electron transport type host material for blue phosphorescent organic light-emitting diodes. High triplet energy of 2.79 eV was obtained and the highest occupied molecular orbital/lowest unoccupied molecular orbital of BePyPy was −6.26 eV/−2.71 eV. The BePyPy host was effective as the host material for blue phosphorescent organic diodes and a high quantum efficiency of 19.7% was achieved. In addition, a mixed host device with the BePyPy host showed high quantum efficiency of 22.0% in the blue device.

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