Dry transfer of graphene to dielectrics and flexible substrates using polyimide as a transparent and stable intermediate layer

Abstract

We demonstrate the direct transfer of graphene from Cu foil to rigid and flexible substrates, such as glass and PET, using as an intermediate layer a thin film of polyimide (PI) mixed with an aminosilane (3-aminopropyltrimethoxysilane) or only PI, respectively. While the dry removal of graphene by an adhesive has been previously demonstrated—being removed from graphite by scotch tape or from a Cu foil by thick epoxy (~20 µm) on Si—our work is the first step towards making a substrate ready for device fabrication using the polymer-free technique. Our approach leads to an article that is transparent, thermally stable—up to 350 °C—and free of polymer residues on the device side of the graphene, which is contrary to the case of the standard wet-transfer process using PMMA. Also, in addition to previous novelty, our technique is fast and easier by using current industrial technology—a hot press and a laminator—with Cu recycling by its mechanical peel-off; it provides high interfacial stability in aqueous media and it is not restricted to a specific material—polyimide and polyamic acids can be used. All the previous reasons demonstrate a feasible process that enables device fabrication.