Electrochemical Control of Single-Molecule Conductance by Fermi- Level Tuning and Conjugation Switching

Masoud Baghernejad, Xiaotao Zhao, Kristian Baruël Ørnsø, Michael Füeg, Pavel Moreno-García, Alexander V. Rudnev, Veerabhadrarao Kaliginedi, Soma Vesztergom, Cancan Huang, Wenjing Hong, Peter Broekmann, Thomas Wandlowski, Kristian Sommer Thygesen, Martin R. Bryce

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Controlling charge transport through a single molecule connected to metallic electrodes remains one of the most fundamental challenges of nanoelectronics. Here we use electrochemical gating to reversibly tune the conductance of two different organic molecules, both containing anthraquinone (AQ) centers, over >1 order of magnitude. For electrode potentials outside the redox-active region, the effect of the gate is simply to shift the molecular energy levels relative to the metal Fermi level. At the redox potential, the conductance changes abruptly as the AQ unit is oxidized/reduced with an accompanying change in the conjugation pattern between linear and cross conjugation. The most significant change in conductance is observed when the electron pathway connecting the two electrodes is via the AQ unit. This is consistent with the expected occurrence of destructive quantum interference in that case. The experimental results are supported by an excellent agreement with ab initio transport calculations.
Original languageEnglish
JournalJournal of the American Chemical Society
Volume136
Issue number52
Pages (from-to)17922-17925
Number of pages4
ISSN0002-7863
DOIs
Publication statusPublished - 2014

Keywords

  • Calculations
  • Electrodes
  • Fermi level
  • Ketones
  • Redox reactions
  • Ab initio transport calculations
  • Electrochemical control
  • Electrochemical gating
  • Electrode potentials
  • Metallic electrodes
  • Molecular energy levels
  • Quantum interference
  • Single molecule conductance
  • Molecules

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