Reduced graphene oxide film with record-high conductivity and mobility

Graphene has attracted significant attention in both scientific and industrial fields. The scalable and high-yield chemical functionalization methods have been widely used to produce graphene, such as reduced graphene oxide (RGO). However, previously reported conductivity (<1500 S cm−1) and mobility (<5 cm2 V−1 s−1) values for RGO film are relatively low, which limits its application in many fields. In this work, we report a RGO film with a record-high conductivity of 6300 S cm−1 and a record-high mobility of 320 cm2 V−1 s−1, which was reduced by Joule heating at an extremely high temperature of 3000 K. Thermal reduction process challenges of Joule heating were overcome by employing a two-step reduction and a curved RGO film. An investigation into how charge transport properties of RGO film are influenced by the reduction temperature was pursued. As the reduction temperature increases, the oxygen-containing functional groups, acting as dopant sources and scattering centers, are gradually removed, such that the carrier density gradually decreases, and the mobility and conductivity gradually increases. The localization length, corresponding to the size of graphitic sp2 domains, is 8.7 nm for the 3000-K-reduced RGO film, which exceeds previously reported values. The unique features of the reported 3000-K-reduced RGO film, such as less defects/impurities and large graphitic sp2 domains within a dense structure, enable both record-high conductivity and mobility.