An electrochemical jump-to-contact STM-break junction approach to construct single molecular junctions with different metallic electrodes

In this communication, we demonstrate an approach for conductance measurement of single molecular junctions with different metallic electrodes based on STM-break junction (STM-BJ) technique with electrochemical strategy. Conductance of molecular junctions formed with succinic acid using Cu, Ag and Au as metal electrodes has been systemically studied, the values being 18.6, 13.2 and 5.6 nS for Cu, Ag and Au electrodes, respectively. The observed decrease in conductance indicates the weakening of electronic coupling efficiency at the electrode–molecule contacts in the order of Cu > Ag > Au, which should be taken into account in evaluating the molecular conductance in the junctions.

Research highlights
► New method to measure single molecule conductance with different metallic electrodes.
► Electrodes forming molecular junctions are in-situ created by electrochemical STM-BJ.
► Cu, Ag and Au binding to succinic acid display a conductance order of Cu > Ag > Au.
► Conductances show different electronic couplings of electrode-molecule contacts.