title: Using a layer-by-layer assembly method to fabricate a uniform and conductive nitrogen-doped graphene anode for indium-tin oxide-free organic light-emitting diodes.
abstract: Highly conductive, uniform, and transparent nitrogen-doped graphene multilayer films were produced by a layer-by-layer (LbL) assembly method. Such a technique was realized by alternate deposition of graphene oxide modified with the cationic surfactant N,N,N-trimethyl-1-dodecanaminium bromide (CTAB) and the anionic surfactant sodium dodecylbenzenesulfonate. In this way, we can achieve a highly conductive (900 S/cm), uniform, and controllable graphene film in terms of thickness, transmittance, and sheet resistance after high-temperature reduction. The improved conductivity is attributed to better graphitization and nitrogen-doping introduced by CTAB. The organic light-emitting diode using such a multilayer graphene film fabricated by the LbL method as an anode obtains higher current density and luminance at low voltage compared to that with an indium-tin oxide (ITO) anode. Moreover, the current efficiency of graphene-based device is comparable to that of an ITO-based device. It is proved that such a nitrogen-doped multilayer graphene film developed by the LbL assembly technique is a promising candidate for a transparent electrode in organic electronics.
authors.affiliation: National Engineering Lab for TFT-LCD Materials and Technologies, and Department of Electronic Engineering, and ‡School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University , Shanghai 200240, People's Republic of China.
authors.forename: Xinkai
authors.initials: X
authors.lastname: Wu
authors.forename: Siying
authors.initials: S
authors.lastname: Li
authors.forename: Yanru
authors.initials: Y
authors.lastname: Zhao
authors.forename: Yanping
authors.initials: Y
authors.lastname: Tang
authors.forename: Jun
authors.initials: J
authors.lastname: Liu
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Guo
authors.forename: Dongqing
authors.initials: D
authors.lastname: Wu
authors.forename: Gufeng
authors.initials: G
authors.lastname: He
keywords: OLED; graphene; layer-by-layer; nitrogen-doping; surfactant