Pure aromatic hydrocarbons with meta-linked phenyl-core and perihedral fluorene substitutions with/without inert groups of tert-butyl： bipolar hosts for blue phosphorescence  

作　　者：Gaowen Liu Chuanjun Wang Baoxiu Mi Minjie Zhuo Changjin Ou Jie Wang Shuchao Zheng Juan Song Zhiqiang Gao Dapeng Cao 

机构地区：[1]Key Laboratory for Organic Electronics and Information Displays & Institute of Advanced Materials (IAM), Jiangsu National Synergistic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts & Telecommunications, Nanjing 210023, China. [2]School of Material Science and Engineering, Jiangsu Engineering Centre for Flat-Panel Displays & Solid-state Lighting, Nanjing University of Posts &Telecommunications, Nanjing 210023, China

出　　处：《Science China Chemistry》2017年第2期223-230,共8页中国科学（化学英文版）

基　　金：supported by the National Natural Science Foundation of China(61474064,61504063);funding from Nanjing University of Posts and Telecommunications (NY214085,NY214177);the Natural Science Foundation of Jiangsu Province(BK20150836);the National Basic Research Program of China (2015CB932200);the National Synergistic Innovation Center for Advanced Materials(SICAM);Synergistic Innovation Center for Organic Electronics and Information Displays;Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD,YX03001);funding from Key Laboratory for Organic Electronics & Information Displays

摘　　要：Two pure hydrocarbon molecules of l,3,5-tris(9-phenyl-9H-fluoren-9-yl)benzene(mTPFB)and l,3,5-tris(2-tert-butyl-9-phenyl-9H-fluoren-9-yl)benzene(tBu-mTPFB)were synthesized.Due to the conjugation blocked connection mode and rigid/bulky substitutions,these two materials possess high triplet energy,enabling them as good hosts for blue phosphor in PhOLEDs.By studying their thermal,electrochemical,electronic absorption and photoluminescent properties,it was found that the influence of the inert tert-butyl group on material photoelectrical properties is negligible.For instance,mTPFB and tBu-mTPFB showed very similar absorption and emission profiles,with almost the same bandgap,triplet energy and energy levels.However,the encapsulation of tert-butyl on the 2-position of 9-phenylfluorene enhanced material thermal stability.Most importantly,carrier transport properties were improved dramatically,as proved by the mono carrier device.Blue phosphorescent OLEDs hosted by tBu-mTPFB showed external quantum efficiency of 15.2%and current efficiency of 23.0 cd/A,which were much higher than that of the OLEDs based on mTPFB with the analogous structure.Two pure hydrocarbon molecules of l,3,5-tris（9-phenyl-9H-fluoren-9-yl）benzene（mTPFB）and l,3,5-tris（2-tert-butyl-9-phenyl-9H-fluoren-9-yl）benzene（tBu-mTPFB）were synthesized.Due to the conjugation blocked connection mode and rigid/bulky substitutions,these two materials possess high triplet energy,enabling them as good hosts for blue phosphor in PhOLEDs.By studying their thermal,electrochemical,electronic absorption and photoluminescent properties,it was found that the influence of the inert tert-butyl group on material photoelectrical properties is negligible.For instance,mTPFB and tBu-mTPFB showed very similar absorption and emission profiles,with almost the same bandgap,triplet energy and energy levels.However,the encapsulation of tert-butyl on the 2-position of 9-phenylfluorene enhanced material thermal stability.Most importantly,carrier transport properties were improved dramatically,as proved by the mono carrier device.Blue phosphorescent OLEDs hosted by tBu-mTPFB showed external quantum efficiency of 15.2%and current efficiency of 23.0 cd/A,which were much higher than that of the OLEDs based on mTPFB with the analogous structure.

关 键 词：pure aromatic hydrocarbon bipolar host thermal stability carrier transport properties tert-butyl moiety 

分 类 号：TN383.1[电子电信—物理电子学] O625.1[理学—有机化学]