Simultaneous Electrochemical Reduction and De lamination of Graphene Oxide Films

Here we report an electrochemical method to simultaneously reduce and delaminate graphene oxide (G-0) thin films deposited on metal (Al and Au) substrates. During the electrochemical reaction, interface charge transfer between the G-0 thin film and the electrode surface was found to be important in eliminating oxygen-containing groups, yielding highly reduced graphene oxide (rG-0). In the meantime, hydrogen bubbles were electrochemically generated at the rG-0 film/electrode interface, propagating the film delamination. Unlike other metal-based G-0 reduction methods, the metal used here was either not etched at all (for Au) or etched a small amount (for Al), thus making it possible to reuse the substrate and lower production costs. The delaminated rG-0 film exhibits a thickness-dependent degree of reduction: greater reduction is achieved in thinner films. The thin rG-0 films having an optical transmittance of 90% (lambda=550 nm) had a sheet resistance of 6390 +/- 447 Omega/square (ohms per square). rG-0-based stretchable transparent conducting films were also demonstrated.