Synthesis, characterization and morphology of reduced graphene oxide–metal–TCNQ nanocomposites

Abstract

A simple method has been developed to synthesize reduced graphene oxide (rGO)–AgTCNQ and rGO–copper–TCNQ nanocomposite films (TCNQ = 7,7,8,8-tetracyanoquinodimethane) from electrodeposited rGO–Ag and rGO–Cu films. The method is based on voltammetric co-reduction of a dispersion containing graphene oxide and a silver or copper metal cation precursor followed by reaction of the rGO–metal films with TCNQ. The morphologies of the organic charge transfer nanomaterials, AgTCNQ and copper–TCNQ, are reaction time dependent. Introduction of the metal–TCNQ nanostructures leads to p-doping of reduced graphene oxide. Pure phase II AgTCNQ nanorods/nanocubes were generated in the reduced graphene oxide film whereas pure phase I copper–TCNQ micro/nanorods grew along the reduced graphene oxide structure. In the Cu case, the bulk material was fully consistent with formation of microcrystalline CuTCNQ but evidence for an underlying film which includes nanocrystalline CuTCNQ (1.3 : 1 Cu : TCNQ ratio) and Cu²⁺ species was also obtained. The achievement of semiconducting phase II AgTCNQ or phase I CuTCNQ in the reduced graphene oxide structure may provide a route for the development of electronic switching devices.