As the blooming of thermally activated delayed fluorescent (TADF) materials, organic light-emitting diodes (OLEDs) possessing high external quantum efficiency (EQE) and low efficiency roll-off are under eager pursuit. Herein, three molecules, 4-(4-(9,9-dimethylacridin-10(9H)-yl)phenyl)-2,6-diphenylpyridine-3,5-dicarbonitrile (Ph-DMAC), 4-(4-(9,9-dimethylacridin-10(9H)-yl)phenyl)-2,6-di(naphthalen-1-yl)pyridine-3,5-dicarbonitrile (Na-DMAC) and 4′-(4-(9,9-dimethylacridin-10(9H)-yl)phenyl)-[3,2′:6′,3″-terpyridine]-3′,5′-dicarbonitrile (3Py-DMAC) with a twisted donor–acceptor structure comprising 3,5-dicynanopryidine with different 2,6-substutents as acceptor and 9,10-dimethylacridan as donor were designed and synthesized. With the highly twisted conformations, effective TADF is achieved in these molecules. Ph-DMAC delivers a high photoluminescent quantum yield (PLQY) of 89% ascribed to its rigid acceptor geometry. Na-DMAC and 3Py-DMAC suffer a slight decrease in efficiency due to excess vibration induced by their naphthyl and pyridinyl moieties. A Ph-DMAC based OLED achieves a very high maximum EQE of 29.1% due to its high PLQY and efficient TADF. With a relatively short delayed lifetime, 3Py-DMAC based OLEDs show only mild efficiency roll-off.

随着热活化延迟荧光（TADF）材料的泛滥，具有高外部量子效率（EQE）和低效率滚降的有机发光二极管（OLED）正受到人们的追捧。在此，三个分子为4-（4-（9,9-二甲基ac啶-10（9 H）-基）苯基）-2,6-二苯基吡啶-3,5-二腈（Ph-DMAC），4-（4- （9,9-二甲基ac啶-10（9 H）-基）苯基）-2,6-二（萘-1-基）吡啶-3,5-二甲腈（Na-DMAC）和4'-（4-（ 9,9-二甲基ac啶-10（9 H）-基）苯基）-[3,2'：6'，3''-三吡啶] -3'，5'-二碳腈（3Py-DMAC）具有扭曲的供体-受体结构，其中包含3,5-二吡啶基吡啶具有不同的2设计合成了以6-取代基为受体，以9,10-二甲基ac啶为供体。通过高度扭曲的构象，可以在这些分子中获得有效的TADF。Ph-DMAC的刚性受体几何结构可实现89％的高光致发光量子产率（PLQY）。由于Na-DMAC和3Py-DMAC的萘基和吡啶基部分引起的过度振动，其效率会略有下降。基于Ph-DMAC的OLED具有很高的PLQY和高效的TADF，因此可实现29.1％的非常高的最大EQE。具有相对较短的延迟寿命，基于3Py-DMAC的OLED仅显示出较低的效率下降。