Planar aromatic anchors control the electrical conductance of gold|molecule|graphene junctions.

The synthesis of a family of alkanethiol molecules with planar aromatic head groups, designed to anchor molecules effectively to graphene electrodes, is reported. Characterisation of self-assembled monolayers of these molecules on a gold surface conductive atomic force microscopy shows that when an aromatic head group is present, the conductance obtained using a graphene coated probe is higher than the conductance obtained using a platinum (Pt) probe. For Pt probe and graphene probe junctions, the tunnelling decay constant of benzyl ether derivatives with an alkanethiol molecular backbone is determined as = 5.

Hydrogen-bond-induced quantum interference in single-molecule junctions of regioisomers.

Solvents can play a significant role in tuning the electrical conductance of single-molecule junctions. In this respect, protic solvents offer the potential to form hydrogen bonds with molecular backbones and induce electrostatic gating their dipole moments. Here we demonstrate that the effect of hydrogen bond formation on conductance depends on whether transport through the junction is controlled by destructive quantum interference (DQI) or constructive quantum interference (CQI).

Charge transport through single-molecule bilayer-graphene junctions with atomic thickness.

The van der Waals interactions (vdW) between π-conjugated molecules offer new opportunities for fabricating heterojunction-based devices and investigating charge transport in heterojunctions with atomic thickness. In this work, we fabricate sandwiched single-molecule bilayer-graphene junctions vdW interactions and characterize their electrical transport properties by employing the cross-plane break junction (XPBJ) technique. The experimental results show that the cross-plane charge transport through single-molecule junctions is determined by the size and layer number of molecular graphene in these junctions.