Highly efficient phosphorescent organic light-emitting diodes using a homoleptic iridium(III) complex as a sky-blue dopant

•Homoleptic tris(phenyl-imidazole) iridium(III) complex Ir(dbi)3 as a sky-blue dopant.•A maximum current efficiency and external quantum efficiency (EQE) of 61.5 cd A−1 and 23.1% obtained.•High efficiencies of 53.5 cd A−1 and 20.1% EQE achieved at the luminance of 1000 cd m−2.

Homoleptic triscyclometalated iridium(III) complex Ir(dbi)3 was used as a dopant for sky blue phosphorescent organic light-emitting diodes (PHOLEDs). Its photophysical, thermal, electrochemical properties as well as the device performances were investigated. Ir(dbi)3 exhibited high quantum yield of 0.52 in solution at room temperature. A maximum current efficiency and external quantum efficiency (EQE) of 61.5 cd A−1 and 23.1% were obtained, which are the highest ever reported for blue homoleptic iridium complexes. High efficiencies of 53.5 cd A−1 and 20.1% EQE were achieved even at the luminance of 1000 cd m−2.

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