Tuning exponential decay factor in oligophenylene molecular junctions with graphene nanoribbon electrodes

We explore the transport properties of oligophenylene molecular junctions, where the center molecule containing 1, 2, or 3 phenyls is sand-wiched between two graphene nanoribbons (GNR) with different edge shapes. According to the obtained results of the first-principles calculations combined with non-equilibrium Green's function method, we find that the molecular length-dependent resistance of all examined oligophenylene molecular junctions follows well the exponential decay law with different slopes, and the exponential decay factor is sensitive to the edge shape of GNRs and the molecule-electrode connecting configuration. These observations indicate that the current through the oligophenylene molecular junction can be effectively tuned by changing the edge shape of GNRs, the molecular length, and the molecular contacting configuration. These findings provide theoretical insight into the design of molecular devices using GNRs as electrodes.