Diarylmethylene-bridged triphenylamine derivatives encapsulated with fluorene: very high Tg host materials for efficient blue and green phosphorescent OLEDs

被引:59
作者
Fan, Cong [1 ]
Chen, Yonghua [2 ]
Jiang, Zuoquan [1 ]
Yang, Chuluo [1 ]
Zhong, Cheng [1 ]
Qin, Jingui [1 ]
Ma, Dongge [2 ]
机构
[1] Wuhan Univ, Dept Chem, Hubei Key Lab Organ & Polymer Optoelect Mat, Wuhan 430072, Peoples R China
[2] Chinese Acad Sci, Changchun Inst Appl Chem, State Key Lab Polymer Phys & Chem, Changchun 130022, Peoples R China
基金
中国国家自然科学基金;
关键词
LIGHT-EMITTING DEVICES; BIPOLAR HOST; ORGANIC ELECTROPHOSPHORESCENCE; CARRIER TRANSPORT; TRIPLET ENERGY; EMISSION; DIODES; COMPLEXES; MECHANISM; MOLECULE;
D O I
10.1039/b927576b
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
Two bridged triphenylamine/fluorene hybrids, BTPAF1 and BTPAF2, were designed and synthesized through Friedel-Crafts reaction. Their thermal, electrochemical, electronic absorption and photoluminescent properties were fully investigated. Very high glass transition temperatures (T-g) were observed at 204 degrees C for BTPAF1 and 211 degrees C for BTPAF2, owing to the introduction of rigid fluorene and bridged triphenylamine unit. The encapsulation of a fluorene unit at the para positions of bridged triphenylamine greatly enhances their electrochemical stability. The linkage by the quaternary carbon atom of the fluorene moiety (C-9) effectively prevents the extension of p-conjugation of the bridged triphenylamine core, and consequently means that the compounds have a high triplet energy of 2.86 eV. Phosphorescent organic light-emitting devices (PHOLEDs) fabricated by using the two compounds as the hosts and the blue emitter bis[2-(4',6'-difluorophenyl) pyridinato-N,C-2']iridium(III) picolate (FIrpic) as the guest exhibit good EL performances with a maximum current efficiency of 20 cd A(-1), a maximum power efficiency of 14 lm W-1, and a maximum external quantum efficiency of 9.4%. Green electrophosphorescent devices by using green-emitter iridium(III) wfac-tris(2-phenylpyridine) [Ir(ppy)(3)] as guest and the two new compounds as the hosts display excellent EL performances with a maximum current efficiency of 75 cd A(-1), a maximum power efficiency of 60 lm W-1, and a maximum external quantum efficiency of 19.5%. The device figures of merit, together with the excellent morphological and electrochemical stabilities, make the new compounds ideal host materials for PHOLEDs, especially for high-temperature applications of devices.
引用
收藏
页码:3232 / 3237
页数:6
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