Single-molecule conductance with nitrile and amino contacts with Ag or Cu electrodes
Abstract
The single-molecule conductance of 1,4-dicyanobenzene (DCB), 1,4-benzenediamine (BDA) and 4,4'-
biphenyldicarbonitrile (BPDC) with Ag and/or Cu electrodes is measured by electrochemical jump-tocontact
STM-break junction. All single-molecule junctions present three sets of conductance values
revealing different contact geometries. We observe that the single-molecule conductance of Ag-BDA-Ag
junction is larger that of Ag-DCB-Ag junction, and DCB with Ag contacts are more conductive than that
with Cu ones. This is related to a different electronic coupling between the molecules and the electrodes.
Tunneling decay constants of 1.70 and 1.68 per phenyl group were found for Ag and Cu electrodes,
respectively. The present study therefore shows that nitrile and amino groups can also be used as
effective anchors for other metals than gold.