| 초록 |
Recently, bipolar host materials are the most promising candidates for achieving high performance PHOLEDs in order to maximize recombination efficiency. However, the development of host material with high triplet energy (ET) is still a great challenge to date to overcome the limitations associated with the present PHOLEDs. Herein, we developed a highly efficient donor-π-acceptor (D-π-A) type bipolar host m-CBPPO comprising of carbazole, 2,2′-dimethylbiphenyl and diphenylphosphoryl as D-π-A unit, respectively. Interestingly, a high ET of 3.02 eV was observed for m-CBPPO due to highly twisted conformation. Furthermore, we incorporated the new host material in PHOLEDs as emissive layer with a new carbene type Ir(cb)3 material as a deep-blue emitter. The optimized devices showed an excellent EQE of 24.8% with a notable CIE (x, y) ≤ 0.15 and high electroluminescence performance with extremely low efficiency roll-off. |
