Three electron transport type host materials, 1DBF-2CNCZ, 2DBF-2CNCZ and 4DBF-2CNCZ, for blue thermally activated delayed fluorescent (TADF) organic light-emitting diodes (OLEDs) were synthesized and characterized. The host materials shared dibenzofuran, benzonitrile and dicyanocarbazole units as the electron transport moieties and had an isomeric molecular structure with different substitution positions of the dibenzofuran moiety. They showed a high triplet energy of above 3.0 eV with a twisted molecular structure and were applied as the electron transport type hosts in the mixed host system with a hole transport type mCBP host for blue TADF OLEDs. The blue TADF OLEDs developed using the 1DBF-2CNCZ host demonstrated a high EQE of over 20% and 31 h lifetime up to 75% of initial luminance at 500 cd m⁻² with a mixed host composition of mCBP : 1DBF-2CNCZ (25 : 75).

中文翻译：

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苯甲腈和双氰基咔唑衍生的电子传输型主体材料，可改善蓝色热活化延迟荧光有机发光二极管的器件寿命

合成并表征了三种电子传输型主体材料1DBF-2CNCZ，2DBF-2CNCZ和4DBF-2CNCZ，用于蓝色热激活延迟荧光（TADF）有机发光二极管（OLED）。主体材料共享二苯并呋喃，苯甲腈和二氰基咔唑单元作为电子传输部分，并具有异构体分子结构，具有不同的二苯并呋喃部分取代位置。它们显示出具有扭曲分子结构的高于3.0 eV的高三重态能量，并被用作带有空穴传输型mCBP主体的混合主体系统中的电子传输型主体，用于蓝色TADF OLED。使用1DBF-2CNCZ开发的蓝色TADF OLED主机在500 cd m ^{-2的条件下}显示出超过20％的高EQE和31 h的寿命，高达初始亮度的75％，混合主机成分为mCBP  ：  1DBF-2CNCZ（25：75）。