title: Highly dispersible edge-selectively oxidized graphene with improved electrical performance.
abstract: We prepared liquid phase exfoliated edge-selectively oxidized graphene (LPEOG) with a high concentration in water (∼14.7 mg ml-1) and a high ratio of a single layer (70%). The edge of graphite was selectively oxidized by step II oxidation of the modified Hummers method, and we subsequently exfoliated the edge-selectively oxidized graphite (EOG) into LPEOG. The edge selective oxidation of the LPEOG was confirmed by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), zeta-potentiometry, Raman spectroscopy, Fourier-transform infrared spectroscopy (FT-IR), atomic force microscopy (AFM), and transmission electron microscopy (TEM). The highly concentrated LPEOG ink can be used in solution processing such as simple drawing or spin casting. Reduced LPEOG showed a higher conductivity (120 000 S m-1) than that of reduced graphene oxide (68 800 S m-1) despite the small lateral size. A transparent conducting film prepared from the LPEOG ink showed a lower surface resistance (∼2.97 kΩ sq-1) at a higher transmittance (>83.0 %T) compared to those of the graphene oxide based film. These results indicate that preservation of π-conjugation of the basal plane of graphene is critical for electrical performance of graphene. Our method facilitates solution processing of graphene for a wide range of applications.
authors.affiliation: Carbon Nanomaterials Design Laboratory, Research Institute of Advanced Materials, and Department of Materials Science and Engineering, Seoul National University, Seoul 151-744, Republic of Korea. crpark@snu.ac.kr.
authors.forename: Jisoo
authors.initials: J
authors.lastname: Park
authors.affiliation: Carbon Nanomaterials Design Laboratory, Research Institute of Advanced Materials, and Department of Materials Science and Engineering, Seoul National University, Seoul 151-744, Republic of Korea. crpark@snu.ac.kr.
authors.forename: Yern Seung
authors.initials: YS
authors.lastname: Kim
authors.affiliation: Carbon Nanomaterials Design Laboratory, Research Institute of Advanced Materials, and Department of Materials Science and Engineering, Seoul National University, Seoul 151-744, Republic of Korea. crpark@snu.ac.kr.
authors.forename: Sae Jin
authors.initials: SJ
authors.lastname: Sung
authors.affiliation: Carbon Nanomaterials Design Laboratory, Research Institute of Advanced Materials, and Department of Materials Science and Engineering, Seoul National University, Seoul 151-744, Republic of Korea. crpark@snu.ac.kr.
authors.forename: Taehoon
authors.initials: T
authors.lastname: Kim
authors.affiliation: Carbon Nanomaterials Design Laboratory, Research Institute of Advanced Materials, and Department of Materials Science and Engineering, Seoul National University, Seoul 151-744, Republic of Korea. crpark@snu.ac.kr.
authors.forename: Chong Rae
authors.initials: CR
authors.lastname: Park