Doping of graphene with polyethylenimine and its effects on graphene-based supercapacitors

Interactions between polymers and graphene can have synergistic effects such as doping, thereby improving the performance of graphene-based devices. In this study, the effects of doping graphene with the n-type dopant polyethylenimine were investigated. The doping-induced changes in the optical contrast of the graphene films were investigated through simulations and experiment. It was experimentally observed that the doping induced a maximum decrease of 63% in the sheet resistance of reduced graphene oxide (RGO) films. The effects of the doping on RGO-based supercapacitor electrodes were examined; the specific capacitance was improved by approximately 3%–11%, with a maximum value of 205 ± 22 F/g (or 260 ± 50 F/cm2). These results can facilitate future research on combining polymers and graphene-based materials for various applications.