In this work, two novel bipolar host materials, 3,5-bis(9H-carbazol-9-yl) phenyl) benzo [1,4,5,6] dioxy [2,3-b] pyrazine (a-CzDp) and 7-(9-phenyl-9H-[3,9′- bicarbazole]-3′-yl) benzo [1,4,5,6] dioxy [2,3-b] pyrazine (b-CzDp) were designed and synthesized. In these two host materials, carbazole and dioxy [2,3-b] pyrazine act as the hole and electron transport unit, respectively. The two dipolar hosts both exhibit good thermal stability and deep highest occupied molecular orbital (HOMO) energy levels of -5.31 eV and −5.39 eV. The phosphorescent organic light-emitting diodes (PhOLEDs) including a-CzDp and b-CzDp as host and red phosphorescent material bis(1-phenylisoquinoline)(acetylacetonate)iridium(III) (Ir(piq)₂acac) as guest in the emitting layer. The corresponding PhOLED devices with a-CzDp and b-CzDp as host exhibit the maximum brightness of 8932 cd m⁻² and 12782 cd m⁻² at 624 nm, together with the maximum external quantum efficiency (EQE) of 10.32% and 13.82%, respectively. B-CzDp based red PhOLED device shows higher EQE and lower turn-on voltage due to the more balanced hole and electron transport. The results demonstrate the potential of a-CzDp and b-CzDp as efficient host for red PhOLEDs.

在这项工作中，两种新型双极性主体材料，3,5-双(9H-咔唑-9-基)苯基)苯并[1,4,5,6]二氧基[2,3-b]吡嗪(a-CzDp)和7-(9-苯基-9H-[3,9'-联咔唑]-3'-基)苯并[1,4,5,6]二氧基[2,3-b]吡嗪(b-CzDp)被设计并合成。在这两种主体材料中，咔唑和二氧基[2,3-b]吡嗪分别充当空穴和电子传输单元。两种偶极主体均表现出良好的热稳定性和深部最高占据分子轨道（HOMO）能级- 5.31 eV 和 -5.39 eV。以a-CzDp和b-CzDp为主体以及红色磷光材料双(1-苯基异喹啉)(乙酰丙酮)铱(III)(Ir(piq) 2)的磷光有机发光二极管(PhOLED ₎acac）作为发光层中的客体。以a-CzDp和b-CzDp为主体的相应PhOLED器件在624 nm处表现出8932 cd m ^-2和12782 cd m ^-2的最大亮度，以及10.32%和13.82%的最大外量子效率（EQE） ， 分别。由于更平衡的空穴和电子传输，基于 B-CzDp 的红色 PhOLED 器件表现出更高的 EQE 和更低的开启电压。结果证明了 a-CzDp 和 b-CzDp 作为红色 PhOLED 的有效主体的潜力。