Modifying organic/metal interface via solvent treatment to improve electron injection in organic light emitting diodes

被引:78
作者
Wang, Qing [1 ]
Zhou, Yan [2 ]
Zheng, Hua [1 ]
Shi, Jian [3 ]
Li, Chunzeng [3 ]
Su, Chanmin Q. [3 ]
Wang, Lei [1 ]
Luo, Chan [1 ]
Hu, Diangang [1 ]
Pei, Jian [2 ]
Wang, Jian [1 ]
Peng, Junbiao [1 ]
Cao, Yong [1 ]
机构
[1] S China Univ Technol, State Key Lab Phys & Chem Luminescence, Inst Polymer Optoelect Mat & Devices, Guangzhou 510640, Guangdong, Peoples R China
[2] Peking Univ, Coll Chem, Key Labs Bioorgan Chem & Mol Engn, Minist Educ, Beijing 100871, Peoples R China
[3] Bruker Corp, Nano Surfaces Div, Santa Barbara, CA 93117 USA
关键词
Organic light emitting diodes; Organic/metal interface; Surface engineering; Solvent treatment; Electron injection barrier; Interface dipole; ENERGY-LEVEL ALIGNMENT; NEUTRAL SURFACTANT; EFFICIENCY; METAL; ELECTROLUMINESCENCE; ALUMINUM; CATHODE; DEVICES; VOLTAGE; LAYER;
D O I
10.1016/j.orgel.2011.07.021
中图分类号
T [工业技术];
学科分类号
08 ;
摘要
By simply spin-coating the solvents, such as ethanol and methanol, on top of the organic active layer, the performance of polymer organic light-emitting diodes is significantly enhanced. The quantum efficiency is increased by as large as 58% for low work function Ba/Al cathode devices after solvent treatment. An interface dipole between the organic layer and the metal layer induced by the solvent, either from the intrinsic dipole or the interaction between the solvent and the cathode metal, is responsible for the device performance improvement. The interface dipole layer, which is confirmed by the Kelvin Probe Force Microscopy and the photovoltaic measurements, lifts the vacuum level on the metal side, thereby reducing the electron injection barrier at the organic/metal interface, and leading to better device performance. (C) 2011 Elsevier B.V. All rights reserved.
引用
收藏
页码:1858 / 1863
页数:6
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