Novel bipolar host materials 4CBZ‐PQ, 3CBZ‐PQ and TPA‐PQ based on carbazole, triphenylamine as electron donors and pyrrolo[1, 2‐a]quinoxaline as an electron acceptor unit has been synthesized and characterized. Their photophysical, thermal and electrochemical properties have also been investigated. These structures show suitable frontier molecular orbital (FMO) energy levels and ensure good thermal and morphological stability. Amongst these bipolar host materials, 4CBZ‐PQ showed high T_g (155.7 ^oC) and T_d (160.7 ^oC) as well as good triplet energy (E_T) of 2.59 eV. Hence, phosphorescent organic light‐emitting diodes (PhOLEDs) were fabricated containing 4CBZ‐PQ, 3CBZ‐PQ and TPA‐PQ as host materials. 4CBZ‐PQ showed best EL performance with a turn‐on voltage of 2.6 V, a maximum brightness of 100388 cd/m², a maximum current efficiency of 18.1 cd/A¹, a maximum power efficiency of 12.9 lm/W and an external quantum efficiency of 15.1%. The RBY (red, brown and yellow) three‐color PhOLED with 4CBZ‐PQ as the host material showed maximum external quantum efficiency of 15.1% for the red device, indicating its potential utility as a host material for highly efficient PhOLEDs.

中文翻译：

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基于Pyrrolo [1，2-a]喹喔啉的双极性主体材料，用于高效的红色磷光OLED

以咔唑，三苯胺为电子供体，吡咯并[1,2-a]喹喔啉为电子受体单元，合成了新型双极性主体材料4CBZ-PQ，3CBZ-PQ和TPA-PQ。还研究了它们的光物理，热和电化学性质。这些结构显示合适的前沿分子轨道（FMO）能级，并确保良好的热和形态稳定性。在这些双极主体材料中，4CBZ-PQ显示出较高的T _g（155.7 ^o C）和T _d（160.7 ^o C）以及良好的三重态能量（E _T）2.59 eV。因此，制造了以4CBZ-PQ，3CBZ-PQ和TPA-PQ为主体材料的磷光有机发光二极管（PhOLED）。4CBZ-PQ在2.6 V的开启电压，100388 cd / m ²的最大亮度，18.1 cd / A ¹的最大电流效率，12.9 lm / W的最大功率效率和外部功率下表现出最佳的EL性能。量子效率为15.1％。以4CBZ-PQ为主体材料的RBY（红色，棕色和黄色）三色PhOLED显示红色器件的最大外部量子效率为15.1％，这表明它潜在地用作高效PhOLED的主体材料。