PhCzBCz exhibits a high triplet energy (2.9 eV), enabling effective confinement of triplet excitons within guest molecules. As a host material in the emitting layer, PhCzBCz enhances charge transfer capabilities while mitigating exciton quenching caused by molecular π–π stacking. This allows the OLED device (such as with DtCzBN-CNBT2) to achive high EQEmax (40.2%) with mild efficiency roll-off (EQE1000 of 20.7%)
−5.4 eV (HOMO)
−2.0 eV (LUMO)