Electrochemical tuning of reduced graphene oxide in printed electrolyte-gated transistors. Impact on charge transport properties

In this work, a surfactant-free formulation of inkjet-printable graphene oxide (GO) is described. The morphology of the printed layers on gold bottom-contact field-effect transistors is studied using atomic force and optical microscopies. An in-situ approach of "green" electrochemical reduction of non-conducting GO into its conductive reduced form, i.e. rGO, is developed. A very significant effect of the reduction degree is observed on the electrical characterizations of rGO in the electrolyte-gated transistor configuration (EGFET), notably on its Dirac point (charge neutrality point) which can be shifted on a range of 1 V. This tuning of the doping level of rGO as a function of the reduction time goes hand in hand with the modulation of charge carriers' mobility over more than one order of magnitude.