Fluorination, and tunneling across molecular junctions

Kung Ching Liao, Carleen M. Bowers, Hyo Jae Yoon, George M. Whitesides

Research output: Contribution to journalArticle

29 Citations (Scopus)

Abstract

This paper describes the influence of the substitution of fluorine for hydrogen on the rate of charge transport by hole tunneling through junctions of the form AgTSO2C(CH2)n(CF2)mT//Ga2O3/EGaIn, where T is methyl (CH3) or trifluoromethyl (CF3). Alkanoate-based self-assembled monolayers (SAMs) having perfluorinated groups (RF) show current densities that are lower (by factors of 20-30) than those of the homologous hydrocarbons (RH), while the attenuation factors of the simplified Simmons equation for methylene (β = (1.05 ± 0.02)nCH2 -1) and difluoromethylene (β = (1.15 ± 0.02)nCF2 -1) are similar (although the value for (CF2)n is statistically significantly larger). A comparative study focusing on the terminal fluorine substituents in SAMs of ω-tolyl- and -phenyl-alkanoates suggests that the C-F//Ga2O3 interface is responsible for the lower tunneling currents for CF3. The decrease in the rate of charge transport in SAMs with RF groups (relative to homologous RH groups) is plausibly due to an increase in the height of the tunneling barrier at the T//Ga2O3 interface, and/or to weak van der Waals interactions at that interface.

Original languageEnglish
Pages (from-to)3852-3858
Number of pages7
JournalJournal of the American Chemical Society
Volume137
Issue number11
DOIs
Publication statusPublished - 2015 Mar 25

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Fluorination
Fluorine
Halogenation
Self assembled monolayers
Charge transfer
Hydrocarbons
Hydrogen
Substitution reactions
Current density

ASJC Scopus subject areas

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

Cite this

Fluorination, and tunneling across molecular junctions. / Liao, Kung Ching; Bowers, Carleen M.; Yoon, Hyo Jae; Whitesides, George M.

In: Journal of the American Chemical Society, Vol. 137, No. 11, 25.03.2015, p. 3852-3858.

Research output: Contribution to journalArticle

Liao, Kung Ching ; Bowers, Carleen M. ; Yoon, Hyo Jae ; Whitesides, George M. / Fluorination, and tunneling across molecular junctions. In: Journal of the American Chemical Society. 2015 ; Vol. 137, No. 11. pp. 3852-3858.
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