Robust graphene-based molecular devices

One of the main challenges to upscale the fabrication of molecular devices is to achieve a mechanically stable device with reproducible and controllable electronic features that operates at room temperature1,2. This is crucial because structural and electronic fluctuations can lead to significant changes in the transport characteristics at the electrode–molecule interface3,4. In this study, we report on the realization of a mechanically and electronically robust graphene-based molecular junction. Robustness was achieved by separating the requirements for mechanical and electronic stability at the molecular level. Mechanical stability was obtained by anchoring molecules directly to the substrate, rather than to graphene electrodes, using a silanization reaction. Electronic stability was achieved by adjusting the π–π orbitals overlap of the conjugated head groups between neighbouring molecules. The molecular devices exhibited stable current–voltage (I–V) characteristics up to bias voltages of 2.0 V with reproducible transport features in the temperature range from 20 to 300 K. Mechanically and electronically stable graphene/molecule/graphene devices can be fabricated by combining a covalent binding of the molecules to the substrate with an optimized intermolecular π–π interaction.