title: Exfoliation of non-oxidized graphene flakes for scalable conductive film.
abstract: The increasing demand for graphene has required a new route for its mass production without causing extreme damages. Here we demonstrate a simple and cost-effective intercalation based exfoliation method for preparing high quality graphene flakes, which form a stable dispersion in organic solvents without any functionalization and surfactant. Successful intercalation of alkali metal between graphite interlayers through liquid-state diffusion from ternary KCl-NaCl-ZnCl(2) eutectic system is confirmed by X-ray diffraction and X-ray photoelectric spectroscopy. Chemical composition and morphology analyses prove that the graphene flakes preserve their intrinsic properties without any degradation. The graphene flakes remain dispersed in a mixture of pyridine and salts for more than 6 months. We apply these results to produce transparent conducting (∼930 Ω/□ at ∼75% transmission) graphene films using the modified Langmuir-Blodgett method. The overall results suggest that our method can be a scalable (>1 g/batch) and economical route for the synthesis of nonoxidized graphene flakes.
authors.affiliation: Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701, Republic of Korea.
authors.forename: Kwang Hyun
authors.initials: KH
authors.lastname: Park
authors.forename: Bo Hyun
authors.initials: BH
authors.lastname: Kim
authors.forename: Sung Ho
authors.initials: SH
authors.lastname: Song
authors.forename: Jiyoung
authors.initials: J
authors.lastname: Kwon
authors.forename: Byung Seon
authors.initials: BS
authors.lastname: Kong
authors.forename: Kisuk
authors.initials: K
authors.lastname: Kang
authors.forename: Seokwoo
authors.initials: S
authors.lastname: Jeon
mesh_terms: D003460:Crystallization / Q000379:methods*; D004553:Electric Conductivity; D006108:Graphite / Q000737:chemistry*; D046911:Macromolecular Substances / Q000737:chemistry; D008422:Materials Testing; D008567:Membranes, Artificial; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D010084:Oxidation-Reduction; D010316:Particle Size; D013499:Surface Properties
chemical_list: D046911:Macromolecular Substances; D008567:Membranes, Artificial; D006108:Graphite