Robust large area molecular junctions based on transparent and flexible electrodes

Abstract

Electrografting of an oligophenylene ethynylene monolayer (OPEH) onto a Mylar®-supported PEDOT : PSS and graphene substrate prior to wet-transfer of a graphene top-electrode has been used to create flexible and transparent large-area Mylar–PEDOT : PSS|OPEH|Graphene molecular junctions. The electrical conductance of the Mylar–PEDOT : PSS|OPEH|Graphene structure was determined by conductive probe atomic force microscopy (c-AFM), sampling various regions across the surfaces of multiple devices. All registered I–V curves (sampling size ∼150 tests) give a sigmoidal response, consistent with through molecule conductance and ruling out the presence of direct electrode contacts or short-circuits. The demonstration of the combined use of Mylar-supported PEDOT : PSS and graphene as alternative electrode materials to conventional metal thin film electrodes in large-area molecular junctions opens avenues to enable flexible and transparent molecular (opto)electronic devices.