Triphenylene containing host materials with high thermal stability for green phosphorescent organic light emitting diode

•Highly efficient phosphorescent green OLED devices with newly synthesized materials.•Application of highly planar triphenylene moieties for good charge transportation.•Effect of relative charge density on phosphorescent green OLED devices.•OLED devices with balanced charge carrier density.•External quantum efficiency over than 20% with newly synthesized green host materials.

We report series of triphenylene derivatives with good electronic properties for the use as host materials for green phosphorescent organic light emitting diodes (PHOLEDs). We applied highly planar triphenylene moieties which could provide good electron transport ability and the carbazole or dibenzothiophene moieties which could provide good hole transport ability to obtain a bipolar host materials for green PHOLEDs. From this approach we achieved relatively good current efficiency up to 64 cd/A and external quantum efficiency up to 20.3%, respectively. This was the much more improved value (by ∼22.3%) compare to that obtained from the 4,4′-N,N′-dicarbazolebiphenyl system as a reference.

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