Selective interface transparency in graphene nanoribbon based molecular junctions

A clear understanding of electrode-molecule interfaces is a prerequisite for the rational engineering of future generations of nanodevices that will rely on single-molecule coupling between components. With a model system, we reveal a peculiar dependence on interfaces in all graphene nanoribbon-based carbon molecular junctions. The effect can be classified into two types depending on the intrinsic feature of the embedded core graphene nanoflake (GNF). For metallic GNFs with |N_A - N_B| = 1, good/poor contact transparency occurs when the core device aligns with the center/edge of the electrode. The situation is reversed when a semiconducting GNF is the device, where N_A = N_B. These results may shed light on the design of real connecting components in graphene-based nanocircuits.