Continuous Reduced Graphene Oxide Film Prepared by Stitching of Nanosheets at the Interface of Two Immiscible Solutions

Abstract

Figure 1. Photograph images (A) graphene oxide (GO) and RGO sheets dispersed in water solution. (B) RGO sheets in immiscible water and chloroform solutions before and after sonication, and after settlement of the sonicated solution. (C) graphene sheets in immiscible water and benzene solutions before sonication and after sonication followed by settlement. Graphene, an atom-thick two-dimensional (2D) honeycomb lattice sheet of sp-bonded carbon atoms, has recently been emerged as a new promising material in various fields. Because of its gigantic charge carrier mobility it could be applied to field-effect transistors as a substitute of silicon. Due to its transparency and high electrical conductivity, it could be used as a substitute of ITO electrode in solar cells and light-emitting diodes. Other superior properties include large surface area, flexibility, strength, stiffness, and thermal conductivity. These provides wide applications of graphene including supercapacitor, battery, sensor, storage and drug delivery. For real applications, large-scale of graphene sheets or films needs to be prepared. Large-area (orders of centimeters) graphene films have recently been fabricated using a chemical vapor deposition (CVD) method on various metal substrates. This method requires a transfer process from the metal substrates to a desired substrate such as a transparent plastic sheet. Simpler methods are a thermal reduction of graphene oxide film prepared via the filtration of graphene sheets, Langmuir-Blodgett (LB) layerby-layer assembly, and filtration of graphene sheets followed by a film transfer. Investigators have now actively pursued various simpler ways of fabricating continuous graphene films or papers. Highly motivated by this, we have challenged to synthesize large-area/scale graphene films from solution.