The redox nature of the resistive switching in nanocomposite thin films based on graphene (graphene oxide) nanoparticles and poly(9-vinylcarbazole)

Abstract

The effects of resistive switching were investigated in composite films based on multifunctional nonconjugated polymers such as poly(9-vinylcarbazole)—PVK mixed with particles of graphene (Gr) and graphene oxide (GO). The concentration of Gr and GO particles in the PVK matrix was varied in the range of 1–3wt%, which is close to the percolation threshold in these systems. It was found that the effect of switching in structures of the form Al/PVK:Gr(GO)/ITO/PET manifests itself in a sharp change of the electrical resistance of the composite film from a low-conducting state to a relatively high-conducting state when applying a bias to Al–ITO electrodes of ∼0.2–0.4V, which is below the threshold switching voltages for similar composites. The cyclic voltammetric measurements of PVK:Gr(GO) films were carried out. It was found that the potential of redox transition of Gr/GO belongs to the interval of redox-switching voltage of PVK:Gr(GO)/ITO/PET composite films with effect of the resistive switching. The possible mechanism of the resistive switching, which is associated with the redox processes as well as with processes of capture and accumulation of charge carriers by Gr (GO) particles introduced into the matrices of the PVK polymer due to reduction/oxidation processes is discussed.