The strategy of acceptor modification is a powerful technique for tuning the emission color of thermally activated delayed fluorescence (TADF) emitters. In this study, we have successfully designed and synthesized three TADF emitters with donor–acceptor (D–A) structures using a 4-(diphenylamino)-2,6-dimethylphenyl (TPAm) donor and various pyridine-3,5-dicarbonitrile (PC) acceptor units. As a result, three compounds named TPAmbPPC, TPAm2NPC, and TPAmCPPC exhibited greenish-yellow to orange-red emissions with high photoluminescent quantum yields (76–100%) in thin films. Remarkably, a greenish-yellow device based on TPAmbPPC and TPAm2NPC showed a high maximum external quantum efficiency (EQE_max) of 39.1 and 39.0%, respectively. Furthermore, benefiting from the suitable steric hindrance between the acceptor and donor, the nondoped organic light-emitting diodes (OLEDs) based on TPAmbPPC demonstrated an exceptional EQE_max of 21.6%, indicating its promising potential as an efficient emitter for the application of OLED applications. Furthermore, orange-red OLED devices based on TPAmCPPC exhibited a high EQE_max of 26.2%, a CE of 50.1 cd A^–1, and a PE of 52.4 lm W^–1.

中文翻译：

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吡啶-3,5-二甲腈受体的修饰用于高效绿-红有机发光二极管

受体修饰策略是调节热激活延迟荧光（TADF）发射器发射颜色的强大技术。在这项研究中，我们使用4-（二苯氨基）-2,6-二甲基苯基（TPAm）供体和各种吡啶-3,5-二甲腈（3,5-dicarbonitrile）成功设计并合成了三种具有供体-受体（D-A）结构的TADF发射器。 PC）受体单位。结果，名为 TPAmbPPC、TPAm2NPC 和 TPAmCPPC 的三种化合物在薄膜中表现出黄绿色至橙红色发射，具有高光致发光量子产率 (76–100%)。值得注意的是，基于 TPAmbPPC 和 TPAm2NPC 的黄绿色器件分别表现出高达39.1% 和 39.0% 的最大外量子效率 (EQE _{max )。}此外，受益于受体和供体之间适当的空间位阻，基于TPAmbPPC的非掺杂有机发光二极管（OLED）表现出高达_21.6 %的出色EQE，表明其作为OLED应用的高效发射器的巨大潜力。此外，基于TPAmCPPC的橙红色OLED器件表现出高达26.2%的EQE _{max 、50.1 cd A} ^–1的CE和52.4 lm W ^–1的PE 。