---
OA_type: closed access
_id: '17988'
abstract:
- lang: eng
  text: We measure conductance and thermopower of single Au–4,4′-bipyridine–Au junctions
    in distinct low and high conductance binding geometries accessed by modulating
    the electrode separation. We use these data to determine the electronic energy
    level alignment and coupling strength for these junctions, which are known to
    conduct through the lowest unoccupied molecular orbital (LUMO). Contrary to intuition,
    we find that, in the high-conductance junction, the LUMO resonance energy is further
    away from the Au Fermi energy than in the low-conductance junction. However, the
    LUMO of the high-conducting junction is better coupled to the electrode. These
    results are in good quantitative agreement with self-energy corrected zero-bias
    density functional theory calculations. Our calculations show further that measurements
    of conductance and thermopower in amine-terminated oligophenyl–Au junctions, where
    conduction occurs through the highest occupied molecular orbitals, cannot be used
    to extract electronic parameters as their transmission functions do not follow
    a simple Lorentzian form.
article_processing_charge: No
article_type: letter_note
author:
- first_name: Taekyeong
  full_name: Kim, Taekyeong
  last_name: Kim
- first_name: Pierre
  full_name: Darancet, Pierre
  last_name: Darancet
- first_name: Jonathan R.
  full_name: Widawsky, Jonathan R.
  last_name: Widawsky
- first_name: Michele
  full_name: Kotiuga, Michele
  last_name: Kotiuga
- first_name: Su Ying
  full_name: Quek, Su Ying
  last_name: Quek
- first_name: Jeffrey B.
  full_name: Neaton, Jeffrey B.
  last_name: Neaton
- first_name: Latha
  full_name: Venkataraman, Latha
  id: 9ebb78a5-cc0d-11ee-8322-fae086a32caf
  last_name: Venkataraman
  orcid: 0000-0002-6957-6089
citation:
  ama: Kim T, Darancet P, Widawsky JR, et al. Determination of energy level alignment
    and coupling strength in 4,4′-bipyridine single-molecule junctions. <i>Nano Letters</i>.
    2014;14(2):794-798. doi:<a href="https://doi.org/10.1021/nl404143v">10.1021/nl404143v</a>
  apa: Kim, T., Darancet, P., Widawsky, J. R., Kotiuga, M., Quek, S. Y., Neaton, J.
    B., &#38; Venkataraman, L. (2014). Determination of energy level alignment and
    coupling strength in 4,4′-bipyridine single-molecule junctions. <i>Nano Letters</i>.
    American Chemical Society. <a href="https://doi.org/10.1021/nl404143v">https://doi.org/10.1021/nl404143v</a>
  chicago: Kim, Taekyeong, Pierre Darancet, Jonathan R. Widawsky, Michele Kotiuga,
    Su Ying Quek, Jeffrey B. Neaton, and Latha Venkataraman. “Determination of Energy
    Level Alignment and Coupling Strength in 4,4′-Bipyridine Single-Molecule Junctions.”
    <i>Nano Letters</i>. American Chemical Society, 2014. <a href="https://doi.org/10.1021/nl404143v">https://doi.org/10.1021/nl404143v</a>.
  ieee: T. Kim <i>et al.</i>, “Determination of energy level alignment and coupling
    strength in 4,4′-bipyridine single-molecule junctions,” <i>Nano Letters</i>, vol.
    14, no. 2. American Chemical Society, pp. 794–798, 2014.
  ista: Kim T, Darancet P, Widawsky JR, Kotiuga M, Quek SY, Neaton JB, Venkataraman
    L. 2014. Determination of energy level alignment and coupling strength in 4,4′-bipyridine
    single-molecule junctions. Nano Letters. 14(2), 794–798.
  mla: Kim, Taekyeong, et al. “Determination of Energy Level Alignment and Coupling
    Strength in 4,4′-Bipyridine Single-Molecule Junctions.” <i>Nano Letters</i>, vol.
    14, no. 2, American Chemical Society, 2014, pp. 794–98, doi:<a href="https://doi.org/10.1021/nl404143v">10.1021/nl404143v</a>.
  short: T. Kim, P. Darancet, J.R. Widawsky, M. Kotiuga, S.Y. Quek, J.B. Neaton, L.
    Venkataraman, Nano Letters 14 (2014) 794–798.
date_created: 2024-09-09T11:24:55Z
date_published: 2014-01-21T00:00:00Z
date_updated: 2025-01-03T07:44:13Z
day: '21'
doi: 10.1021/nl404143v
extern: '1'
external_id:
  pmid:
  - '24446585'
intvolume: '        14'
issue: '2'
language:
- iso: eng
month: '01'
oa_version: None
page: 794-798
pmid: 1
publication: Nano Letters
publication_identifier:
  eissn:
  - 1530-6992
  issn:
  - 1530-6984
publication_status: published
publisher: American Chemical Society
quality_controlled: '1'
scopus_import: '1'
status: public
title: Determination of energy level alignment and coupling strength in 4,4′-bipyridine
  single-molecule junctions
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 14
year: '2014'
...