Tunneling Probability Increases with Distance in Junctions Comprising Self-Assembled Monolayers of Oligothiophenes

Yanxi Zhang, Saurabh Soni, Theodorus L. Krijger, Pavlo Gordiichuk, Xinkai Qiu, Gang Ye, Harry T. Jonkman, Andreas Herrmann, Karin Zojer, Egbert Zojer, Ryan C. Chiechi

Research output: Contribution to journalArticleResearchpeer-review

Abstract

Molecular tunneling junctions should enable the tailoring of charge-transport at the quantum level through synthetic chemistry but are hindered by the dominance of the electrodes. We show that the frontier orbitals of molecules can be decoupled from the electrodes, preserving their relative energies in self-assembled monolayers even when a top-contact is applied. This decoupling leads to the remarkable observation of tunneling probabilities that increase with distance in a series of oligothiophenes, which we explain using a two-barrier tunneling model. This model is generalizable to any conjugated oligomers for which the frontier orbital gap can be determined and predicts that the molecular orbitals that dominate tunneling charge-transport can be positioned via molecular design rather than by domination of Fermi-level pinning arising from strong hybridization. The ability to preserve the electronic structure of molecules in tunneling junctions facilitates the application of well-established synthetic design rules to tailor the properties of molecular-electronic devices.

Original languageEnglish
Pages (from-to)15048-15055
Number of pages8
JournalJournal of the American Chemical Society
Volume140
Issue number44
DOIs
Publication statusPublished - 7 Nov 2018

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Self assembled monolayers
Charge transfer
Electrodes
Molecular electronics
Molecules
Molecular orbitals
Fermi level
Oligomers
Electronic structure
Observation
Equipment and Supplies

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

Fields of Expertise

  • Advanced Materials Science

Cite this

Tunneling Probability Increases with Distance in Junctions Comprising Self-Assembled Monolayers of Oligothiophenes. / Zhang, Yanxi; Soni, Saurabh; Krijger, Theodorus L.; Gordiichuk, Pavlo; Qiu, Xinkai; Ye, Gang; Jonkman, Harry T.; Herrmann, Andreas; Zojer, Karin; Zojer, Egbert; Chiechi, Ryan C.

In: Journal of the American Chemical Society, Vol. 140, No. 44, 07.11.2018, p. 15048-15055.

Research output: Contribution to journalArticleResearchpeer-review

Zhang, Y, Soni, S, Krijger, TL, Gordiichuk, P, Qiu, X, Ye, G, Jonkman, HT, Herrmann, A, Zojer, K, Zojer, E & Chiechi, RC 2018, 'Tunneling Probability Increases with Distance in Junctions Comprising Self-Assembled Monolayers of Oligothiophenes' Journal of the American Chemical Society, vol. 140, no. 44, pp. 15048-15055. https://doi.org/10.1021/jacs.8b09793
Zhang, Yanxi ; Soni, Saurabh ; Krijger, Theodorus L. ; Gordiichuk, Pavlo ; Qiu, Xinkai ; Ye, Gang ; Jonkman, Harry T. ; Herrmann, Andreas ; Zojer, Karin ; Zojer, Egbert ; Chiechi, Ryan C. / Tunneling Probability Increases with Distance in Junctions Comprising Self-Assembled Monolayers of Oligothiophenes. In: Journal of the American Chemical Society. 2018 ; Vol. 140, No. 44. pp. 15048-15055.
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