Highly Twisted Carbazole-Oxadiazole Hybrids as Universal Bipolar Hosts for High Efficiency PhOLEDs

被引：27

作者：

Cheng, Shuo-Hsien ^{[1
]}

Hung, Wen-Yi ^{[2
]}

Cheng, Ming-Hung ^{[2
]}

Chen, Hsiao-Fan ^{[1
]}

Lee, Gene-Hsiang ^{[1
]}

Chung, Chin-Lung ^{[1
]}

Yeh, Tzu-Chin ^{[1
]}

Tang, Wei-Chieh ^{[1
]}

Huang, Shou-Ling ^{[1
]}

Wong, Ken-Tsung ^{[1
,3
]}

机构：

[1] Natl Taiwan Univ, Dept Chem, Taipei 10617, Taiwan

[2] Natl Taiwan Ocean Univ, Inst Optoelect Sci, Chilung 20224, Taiwan

[3] Acad Sinica, Inst Atom & Mol Sci, Taipei 10617, Taiwan

来源：

ADVANCED ELECTRONIC MATERIALS | 2016年 / 2卷 / 01期

关键词：

LIGHT-EMITTING DEVICES; EXTERNAL QUANTUM EFFICIENCY; TRIPLET ENERGY; CHARGE-TRANSFER; BLUE; GREEN; DIODES; RED; FLUORESCENT; ELECTROPHOSPHORESCENCE;

D O I：

10.1002/aelm.201500241

中图分类号：

TB3 [工程材料学];

学科分类号：

0805 ; 080502 ;

摘要：

Four bipolar molecules oDOXA, mDOXA, oOXA, and mOXA composed of a hole-transport carbazole (donor, D) and an electron-transport 1,3,4-oxadiazole (acceptor, A) bridged with different pi-spacers (biphenyl or o-terphenyl) are synthesized, characterized, and used as host materials for various colored phosphorescent OLEDs (PhOLEDs). The highly twisted geometry established via multiple ortho/meta-connections effectively inhibits direct electronic D-A coupling and gives these bipolar molecules similar high triplet energies (approximate to 2.70 eV). In addition, distinctive bipolar transport capabilities are observed by time-of-flight technique (mu(h) approximate to mu(e) approximate to 10(-5) - 10(-6) cm(2) V-1 s(-1)). The D/A connection topology is found to subtly govern the physical properties, rendering these new molecules suitable for serving as bipolar host materials. Among the four host materials, oOXA using the tandem ortho-linkage terphenyl as a linker outperforms the other three hosts in terms of the device efficiency, in which the maximum external quantum efficiencies (eta(ext)) of the corresponding PhOLEDs are as high as 19.4%, 21.3%, 20.9%, 20.1%, and 19.0% for blue, green, yellow, orange, and red PhOLEDs, respectively. Moreover, a single-host multilayered warm-white OLED based on oOXA also shows remarkable efficiency (19.8%, 42.4 cd A(-1), and 38.6 lm W-1) with high color-rendering index of 86.8 and stable chromaticity.

引用

页数：10

共 73 条

[71] A bulky pyridinylfluorene-fuctionalizing approach to synthesize diarylfluorene-based bipolar host materials for efficient red, green, blue and white electrophosphorescent devices [J].