Evolution, structure, and electrical performance of voltage-reduced graphene oxide

Abstract Voltage-induced graphene oxide (GO) reduction is a facile and environmentally benign procedure for removing oxygen-containing functional groups from GO and recovering electrical conductivity. In this work, we perform a comprehensive investigation of the reduction process, structure, and electrical properties associated with voltage-reduced graphene oxide (V-rGO), obtained by applying a voltage between lateral electrode pairs. In situ optical microscopy during reduction reveals the growth of dendritic filaments of V-rGO that advance from the negative to positive terminal, eventually bridging and filling the entire electrode gap region. The growth rate of V-rGO filaments is found to sharply increase with humidity and film thickness. Through the use of varied electrode geometries, we demonstrate that V-rGO growth proceeds along electric field lines, opposite the field’s direction. Following reduction, significant recovery of sp 2 carbon bonding and removal of oxygen-containing functional groups leads to electrical performance that is competitive with standard reduction schemes. Variable temperature resistance measurements identify Efros-Shklovskii variable-range hopping as the dominant transport mechanism, a result that is consistent with V-rGO acting as a polydisperse quantum dot array. Overall, this work suggests that voltage-induced reduction can be used in place of more cumbersome and hazardous reduction methods.