Highly\nConductive and Transparent Reduced Graphene Oxide Nanoscale Films\nvia Thermal Conversion of\nPolymer-Encapsulated Graphene Oxide Sheets

Abstract

Despite\nnoteworthy progress in the fabrication of large-area graphene sheetlike\nnanomaterials, the vapor-based processing still requires sophisticated\nequipment and a multistage handling of the material. An alternative\napproach to manufacturing functional graphene-based films includes\nthe employment of graphene oxide (GO) micrometer-scale sheets as precursors.\nHowever, search for a scalable manufacturing technique for the production\nof high-quality GO nanoscale films with high uniformity and high electrical\nconductivity is still continuing. Here we show that conventional dip-coating\ntechnique can offer fabrication of high quality mono- and bilayered\nfilms made of GO sheets. The method is based on our recent discovery\nthat encapsulating individual GO sheets in a nanometer thick molecular\nbrush copolymer layer allows for the nearly perfect formation of the\nGO layers via dip coating from water. By thermal reduction the bilayers\n(cemented by a carbon-forming polymer linker) are converted into highly\nconductive and transparent reduced GO films with a high conductivity\nup to 10⁴ S/cm and optical transparency on the level of\n90%. The value is the highest electrical conductivity reported for\nthermally reduced nanoscale GO films and is close to the conductivity\nof indium tin oxide currently in use for transparent electronic devices,\nthus making these layers intriguing candidates for replacement of\nITO films.