Efficiency phosphorescent OLEDs with a low roll-off based on a hetero-triplet iridium complex

被引：15
作者：
Han, Liangliang [1 ]
Zhang, Dongyu [2 ]
Wang, Jun [1 ]
Lan, Zhenggang [1 ]
Yang, Renqiang [1 ]
机构：
[1] Chinese Acad Sci, Qingdao Inst Bioenergy & Bioproc Technol, Key Lab Biobased Mat, Qingdao 266101, Peoples R China
[2] Chinese Acad Sci, Suzhou Inst Nanotech & Nanobion, Suzhou 215123, Peoples R China
来源：
DYES AND PIGMENTS | 2015年 / 113卷
基金：
中国国家自然科学基金;
关键词：
Heterocyclometalated iridium complex; Hetero-triplet iridium complex; Triplet-triplet annihilation; Efficiency roll-off; Exciton density; OLED; LIGHT-EMITTING DEVICES; ORGANIC ELECTROPHOSPHORESCENCE; ELECTROCHEMICAL-CELLS; TRANSIENT ANALYSIS; ENERGY-TRANSFER; DIODES; BLUE; ANNIHILATION; DERIVATIVES; EMISSION;
D O I：
10.1016/j.dyepig.2014.10.001
中图分类号：
O69 [应用化学];
学科分类号：
081704 ;
摘要：
In order to explore the triplet triplet annihilation in cyclometalated iridium complexes, a hetero-triplet iridium complex [Ir(ppy)(2)pbi] employing two 2-phenylpyridine (Hppy) ligands and one 1,2-diphenyl-1H-benzo[d]-imidazole (Hpbi) ligand with similar triplet energies was synthesized. A device based on Ir(ppy)(2)pbi exhibited high current efficiency 26.7 cd/A at high doping concentration 12 wt%. More interestingly, the current efficiency was still maintained at 25.8 cd/A when the current density was above 253.2 mA/cm(2). The efficiency roll-off was only about 3.4%, much lower than that of traditional cyclometalated iridium complexes. It is proposed that the complicated energy level and unsymmetical ligand in Ir(ppy)(2)pbi may help to suppress the triplet triplet annihilation. (C) 2014 Elsevier Ltd. All rights reserved.
引用
收藏
页码：649 / 654
页数：6
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