Workfunction-Tunable, N-Doped Reduced Graphene Transparent Electrodes for High-Performance Polymer Light-Emitting Diodes

被引:286
作者
Hwang, Jin Ok [1 ]
Park, Ji Sun [1 ]
Choi, Dong Sung [1 ]
Kim, Ju Young [1 ]
Lee, Sun Hwa [1 ]
Lee, Kyung Eun [1 ]
Kim, Yong-Hyun [2 ]
Song, Myoung Hoon [3 ]
Yoo, Seunghyup [4 ]
Kim, Sang Ouk [1 ]
机构
[1] Korea Adv Inst Sci & Technol, Dept Mat Sci & Engn, KI Nanocentury, Taejon 305701, South Korea
[2] Korea Adv Inst Sci & Technol, Grad Sch Nanosci & Technol WCU, Taejon 305701, South Korea
[3] Ulsan Natl Inst Sci & Technol UNIST, Sch Mech & Adv Mat Engn, Ulsan 689805, South Korea
[4] Korea Adv Inst Sci & Technol, Dept Elect Engn, Taejon 305701, South Korea
关键词
doping; graphene; workfunction; electrode; light-emitting diode; STABLE METAL-OXIDES; FIELD-EMISSION; AQUEOUS DISPERSIONS; FILMS; AREA; REDUCTION; DEPOSITION; GROWTH;
D O I
10.1021/nn203176u
中图分类号
O6 [化学];
学科分类号
0703 ;
摘要
Graphene is a promising candidate to complement brittle and expensive transparent conducting oxides. Nevertheless, previous research efforts have paid little attention to reduced graphene, which can be of great benefit due to low-cost solution processing without substrate transfer. Here we demonstrate workfunction-tunable, highly conductive, N-doped reduced graphene film, which is obtainable from the spin-casting of graphene oxide dispersion and can be successfully employed as a transparent cathode for high-performance polymer light-emitting diodes (PLEDs) as an alternative to fluorine-doped tin oxide (FTO). The sheet resistance of N-doped reduced graphene attained 300 Omega/square at 80% transmittance, one of the lowest values ever reported from the reduction of graphene oxide films. The optimal doping of quaternary nitrogen and the effective removal of oxygen functionalities via sequential hydrazine treatment and thermal reduction accomplished the low resistance. The PLEDs employing N-doped reduced graphene cathodes exhibited a maximum electroluminescence efficiency higher than those of FTO-based devices (4.0 cd/A for FTO and 7.0 cd/A for N-doped graphene at 17 000 cd/m(2)). The reduced barrier for electron injection from a workfunction-tunable, N-doped reduced graphene cathode offered this remarkable device performance.
引用
收藏
页码:159 / 167
页数:9
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