Efficient circularly polarized photoluminescence and electroluminescence of chiral spiro-skeleton-based thermally activated delayed fluorescence molecules  

作　　者：Yi-Pin Zhang Shi-Quan Song Meng-Xi Mao Cheng-Hui Li You-Xuan Zheng Jing-Lin Zuo 

机构地区：[1]State Key Laboratory of Coordination Chemistry,Jiangsu Key Laboratory of Advanced Organic Materials,School of Chemistry and Chemical Engineering,Nanjing University,Nanjing 210023,China [2]MaAnShan High-Tech Research Institute of Nanjing University,Maanshan 238200,China

出　　处：《Science China Chemistry》2022年第7期1347-1355,共9页中国科学（化学英文版）

基　　金：supported by the National Natural Science Foundation of China (21975119, 51773088)。

摘　　要：Chiral thermally activated delayed fluorescence(TADF) molecules showing circularly polarized luminescence(CPL) have great potential in 3D displays. However, the relationships among CPL property, device performance and molecule structure are still not clear. In this article, we develop a strategy to promote dissymmetry factors without sacrifice in device performance and study the impact of molecule structures towards CPL property. Three novel TADF enantiomers are synthesized and studied.(R/S)-SCN with diminutive cyano group as an acceptor shows dissymmetry factor |gPL| ≈ 1.4×10^(-3) and noticeable organic light-emitting diode(OLED) performances with a maximum external quantum efficiency(EQEmax) of 23.0%. For(R/S)-SPHCN, the prolonged electron withdrawing group benzonitrile enhances |gPL| up to 3.6×10^(-3) with decreased device EQEmaxof 15.4%. By further replacing benzonitrile with(trifluoromethyl)pyridine, the enantiomers of(R/S)-SCFPY show similar |gPL| factors of 3.5×10^(-3) and device EQE_(max)up to 23.3%, which represents the highest efficiency among sprio-type TADF materials based OLEDs. Furthermore, the OLEDs also show obvious circularly polarized electroluminescence with gELfactors of-1.4/1.8×10^(-3),-3.6/3.6×10^(-3) and-3.7/3.6×10^(-3), respectively. These results indecate by delicate functional group engineering, high g factor can be achieved while maintaining decent device performances. Besides,(R/S)-SCFPY represents an impressive TADF emitter, which shows promoted g factor and recorded high device EQE_(max)among similar molecules.

关 键 词：chiral spiro-skeleton thermally activated delayed fluorescence circularly polarized photoluminescence circularly polarized electroluminescence dissymmetry factor 

分 类 号：TB30[一般工业技术—材料科学与工程] TN383.1[电子电信—物理电子学]