Single-layer triplet white polymer light-emitting diodes incorporating polymer oxides: Effect of charge trapping at phosphorescent dopants

被引：27
作者：
Chen, Fang-Chung [1 ,2 ]
Chien, Shang-Chieh [1 ,3 ]
Chen, Yung-Shiuan [1 ,2 ]
机构：
[1] Natl Chiao Tung Univ, Dept Photon, Hsinchu 30010, Taiwan
[2] Natl Chiao Tung Univ, Display Inst, Hsinchu 30010, Taiwan
[3] Natl Chiao Tung Univ, Inst Electroopt Engn, Hsinchu 30010, Taiwan
来源：
APPLIED PHYSICS LETTERS | 2009年 / 94卷 / 04期
关键词：
conducting polymers; electron traps; hole traps; organic light emitting diodes; organic semiconductors; phosphorescence; DEVICES; EFFICIENCY; EMISSION;
D O I：
10.1063/1.3075066
中图分类号：
O59 [应用物理学];
学科分类号：
摘要：
This paper describes the effects of charge trapping on the device performances of triplet polymer light-emitting diodes (PLEDs) after the cathode contact had been improved through the blending of poly(ethylene glycol) (PEG) into the active layer. The external quantum efficiency (EQE) was enhanced when the dopant tended to trap electrons. In contrast, we observed no EQE enhancement for the device featuring a hole-trapping dopant. Because PEG promoted electron injection, more electrons were trapped in the triplet molecules, thereby enhancing the probability of recombination. Finally, after incorporating PEG, we further achieved white PLEDs exhibiting both high EQE and high power efficiency.
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页数：3
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