Designing a bipolar host material for blue phosphorescent OLEDs: Phenoxy-carbazole substituted triazine

A novel phenoxy-carbazole substituted triazine host material (PCTrz) was synthesised. PCTrz exhibits a high triplet bandgap of 2.91 eV and a high glass transition temperature of 148 °C. A non-conjugated ether bond separates the oxidation- and reduction-site in the molecule. Good charge carrier transport properties in single carrier devices prove the potential as host for blue phosphorescent emitters. An organic light emitting diode with PCTrz as host for FIrpic exhibited a high current efficiency of 13.5 cd/A a luminance of 1000 cd/m2 and a maximum luminance of 29,000 cd/m2.

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► Novel bipolar host material PCTrz for blue phosphorescent OLEDs developed.
► PCTrz exhibits a high triplet bandgap of 2.91 eV.
► PCTrz has a high glass transition temperature of 148 °C.
► OLEDs with FIrpic shows maximum luminance of 29,000 cd/m2.
► High current efficiency of 13.5 cd/A at 1000 cd/m2 was achieved.