Work function engineering of graphene oxide via covalent functionalization for organic field-effect transistors

We report a simple method to produce work-function-tuned graphene nanosheets based on the nucleophilic substitution of the epoxy groups on graphene oxide. The electrical property of the graphene oxide is controlled dramatically, which results in the apparent work functions in a broad range between 3.73 eV and 5.1 eV, by attaching various functional groups on the graphene surface. As a proof of concept, we successfully demonstrated organic field effect transistors incorporating the functionalized graphene nanosheet interlayers. Here, when nanosheets were applied in an organic transistor as the interlayer material between electrodes and organic channel, the device performance was significantly improved. Our approach can be utilized to increase the performance and the flexibility of various advanced carbon-material-based hybrid electrical devices.