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Title: Mapping the Transmission Functions of Single-Molecule Junctions

Charge transport characteristics of single-molecule junctions are often governed by a transmission function that dictates the probability of electrons or holes tunneling across the junction. Here, we present a new and simple technique for measuring the transmission function of molecular junctions in the coherent tunneling limit, over an energy range of 2 eV around the Fermi energy. We create molecular junctions in an ionic environment with electrodes having different areas exposed, which results in the formation of electric double layers of dissimilar density on the two electrodes. This allows us to electrostatically shift the molecular resonance relative to the junction Fermi levels in a manner that depends on the sign of the applied bias, enabling us to map out the junction’s transmission function and determine the dominant orbital for charge transport in the molecular junction. We demonstrate this technique using two groups of molecules: one group having molecular resonance energies relatively far from EF and one group having molecular resonance energies within the accessible bias window. Our results compare well with previous electrochemical gating data and with transmission functions computed ab initio. Furthermore, with the second group of molecules, we are able to examine the behavior of a molecular junctionmore » as a resonance shifts into the bias window. This work provides a new, experimentally simple route for exploring the fundamentals of charge transport at the nanoscale.« less
 [1] ;  [1] ;  [2] ;  [3] ;  [4] ;  [1] ;  [1]
  1. Columbia Univ., New York, NY (United States)
  2. Wuhan Univ. of Technology (China)
  3. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of California, Berkeley, CA (United States)
  4. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of California, Berkeley, CA (United States); Kavli Energy Nano Sciences Inst., Berkeley, CA (United States)
Publication Date:
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Nano Letters
Additional Journal Information:
Journal Volume: 16; Journal Issue: 6; Journal ID: ISSN 1530-6984
American Chemical Society
Research Org:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
OSTI Identifier: