The development of red thermally activated delayed fluorescence (TADF) emitters having excellent optoelectronic properties and satisfactory electroluminescence efficiency is full of challenges due to strict molecular design principles. Two red TADF molecules, 3‐(9,9‐dimethylacridin‐10(9H)‐yl)acenaphtho[1,2‐b]quinoxaline‐9,10‐dicarbonitrile and 3‐(2,7‐dimethyl‐10H‐spiro[acridine‐9,9′‐fluoren]‐10‐yl)acenaphtho[1,2‐b]quinoxaline‐9,10‐dicarbonitrile, are developed by adopting a donor–acceptor molecular architecture bearing an electron‐accepting acenaphtho[1,2‐b]quinoxaline‐9,10‐dicarbonitrile (ANQDC) moiety and a 9,9‐dimethyl‐9,10‐dihydroacridine or 2,7‐dimethyl‐10H‐spiro[acridine‐9,9′‐fluorene] electron donor. The combined effects of rigid and planar D/A moieties and highly steric hindrance between D and A groups endow both molecules with high rigidity to suppress nonradiative decay processes, resulting in high photoluminescence quantum efficiencies (Φ_PLs) of up to 95%. Attributed to the linear and planar acceptor motif and rod‐like molecular configuration, both emitters achieve high horizontal ratios of emitting dipole orientation of ≈80%. The organic light‐emitting diodes (OLEDs) based on both emitters exhibit red emissions peaking at ≈615 nm and successfully afford ultrahigh electroluminescence performance with an external quantum efficiency of nearly 28% and a power efficiency of above 50 lm W⁻¹, on par with the state‐of‐the‐art device efficiency for red TADF OLEDs. This presents a feasible design strategy for excellent TADF emitters simultaneously possessing high Φ_PLs and horizontally aligned emitting dipoles.

中文翻译：

---

同时具有高光致发光量子效率和优先水平发射偶极子取向的红色热激活延迟荧光发射体

由于严格的分子设计原理，具有优异的光电性能和令人满意的电致发光效率的红色热激活延迟荧光（TADF）发射器的开发充满了挑战。两个红色TADF分子，3-（9,9- dimethylacridin-10（9 ħ） -基）苊并[1,2-B]喹喔啉-9,10-二腈和3-（2,7-二甲基10 ħ -螺[ac啶9,9'-芴] -10-基）ac [1,2-b]喹喔啉-9,10-二腈是通过采用带有电子接受的供体-受体分子结构开发的[1] ，2-b]喹喔啉-9,10-二腈（ANQDC）部分和9,9-二甲基-9,10-二氢ac啶或2,7-二甲基-10 H螺[[啶-9,9'-芴]电子供体。d和A基团之间的刚性的和平面的d / A部分和高度位阻的组合效果赋予高刚性两种分子以抑制非辐射衰变过程，导致高的光致发光量子效率（Φ _PL S）达到95％以上的。归因于线性和平面受体基序以及棒状分子构型，两个发射器均实现了约80％的发射偶极子取向高水平比。基于两个发射器的有机发光二极管（OLED）的红色发射峰均在≈615nm处达到峰值，并成功提供超高电致发光性能，外部量子效率接近28％，功率效率超过50 lm W ^-1，与红色TADF OLED的最新设备效率相当。这为优良TADF发射器同时具有高Φ一种可行的设计策略_PL S和水平对准的发射偶极子。