High triplet energy hosts were developed through the modification of the substitution position of carbazole units. Two carbazole-dibenzofuran-derived compounds, 9,9′-(dibenzo[b,d]furan-2,6-diyl)bis(9H-carbazole) (26CzDBF) and 4,6-di(9H-carbazol-9-yl)dibenzo[b,d]furan (46CzDBF), were synthesized for achieving high triplet energy hosts. In comparison with the reported hole transport type host, 2,8-di(9H-carbazol-9-yl)dibenzo[b,d]furan (28CzDBF), 26CzDBF and 46CzDBF maintained high triplet energy over 2.95 eV. The device performances of the hosts were evaluated with electron transport type host, 2-phenyl-4, 6-bis(3-(triphenylsilyl)phenyl)-1,3,5-triazine (mSiTrz), to comprise a mixed host system. The deep blue phosphorescent device of 26CzDBF:mSiTrz with [[5-(1,1-dimethylethyl)-3-phenyl-1H-imidazo[4,5-b]pyrazin-1-yl-2(3H)-ylidene]-1,2-phenylene]bis[[6-(1,1-dimethylethyl)-3-phenyl-1H-imidazo[4,5-b]pyrazin-1-yl-2(3H)-ylidene]-1,2-phenylene]iridium (Ir(cb)₃) dopant exhibited high external quantum efficiency of 22.9% with a color coordinate of (0.14, 0.16) and device lifetime of 1400 h at 100 cd m⁻². The device lifetime was extended by 75% compared to the device lifetime of 28CzDBF:mSiTrz (800 h). These results demonstrated that the asymmetric and symmetric substitution of carbazole can make differences in the device performance of the carbazole- and dibenzofuran- derived hosts.

中文翻译：

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咔唑-二苯并呋喃基高三重态能量主体的取代位置对蓝色磷光有机发光二极管器件稳定性的影响

通过改变咔唑单元的取代位置，开发了高三重态能量主体。两种咔唑-二苯并呋喃衍生的化合物，9,9'-（二苯并[b，d]呋喃-2,6-二基）双（9 H-咔唑）（26CzDBF）和4,6-二（9 H-咔唑-合成了9-基）二苯并[b，d]呋喃（46CzDBF）以实现高三重态能量主体。与报告的空穴传输类型宿主相比，2,8-di（9 H-咔唑-9-基）二苯并[b，d]呋喃（28CzDBF），26CzDBF和46CzDBF在2.95 eV上保持高三重态能量。用电子传输型主机2-苯基-4、6-双（3-（三苯基硅烷基）苯基）-1,3,5-三嗪（mSiTrz）评估主机的器件性能，以构成混合主机系统。具有[[5-（1,1-二甲基乙基）-3-苯基-1 H-咪唑并[4,5-b]吡嗪-1-基-2（3 H）-亚烷基]的26CzDBF：mSiTrz的深蓝色磷光器件] -1,2-亚苯基]双[[6-（1,1-二甲基乙基）-3-苯基-1 H-咪唑并[4,5-b]吡嗪-1-基-2（3 H）-亚烷基] -1,2-亚苯基]铱（Ir（cb）₃）掺杂剂在100 cd m ^{-2的条件下}具有22.9％的高外部量子效率，色坐标为（0.14，0.16），器件寿命为1400 h。。与28CzDBF：mSiTrz的设备寿命（800小时）相比，设备的寿命延长了75％。这些结果表明，咔唑的不对称和对称取代可以使咔唑和二苯并呋喃衍生的主体的器件性能产生差异。