Phosphine Sulfide As an Anchor Unit for Metal-Molecule Junction

Abstract

The metal-molecule junctions have recently attracted increasing attention in the field of molecular electronics. The anchor groups that connect molecules with electrodes are of particular importance, since they play crucial roles in the electron transport. We here report that phosphine sulfides act as an anchor unit in single molecule junctions. As a model system, we designed and synthesized oligo(p-phenylene)s having dibenzophosphole sulfide (DBPS) groups as the anchor groups. The conductance measurements of the single molecule junctions using the STM method and theoretical calculations revealed that the DBPS indeed acted as an anchor unit. In addition, the electron-transport mechanism of the DBPS-anchored systems was found to be totally different from that of the thiol-anchored analogues due to the highly electron-accepting character of the DBPS groups.