Hybrid Molecular Junctions Using Au–S and Au−π Bindings

Electrically conductive molecular junctions are highly desirable components for applications in future molecular-scale electronic circuits. Here, we demonstrate an electrically conductive hybrid molecular junction that consists of Au–S and Au−π bindings using a sumanene derivative with three phosphine–sulfide anchoring groups at the periphery of the sumanene backbone. The molecular junction was prepared between the Au electrodes by the scanning tunneling microscopy-based break junction method. The three anchoring groups and the sumanene backbone in the junction form the Au–S chemical bonds and Au−π direct bonds, respectively. The Au–S chemical binding immobilized the molecule on the Au electrode and provided the high mechanical stability of the junction, while the direct Au−π binding led to the large metal–molecule electric coupling and high electronic conductance of the molecular junction. This study analyzes the molecular design of the electrically conductive molecular junctions based on the hybrid binding groups.