The rate of charge tunneling is insensitive to polar terminal groups in self-assembled monolayers in AgTSS(CH2) nM(CH2)mT//Ga2O3/EGaIn junctions

Hyo Jae Yoon, Carleen M. Bowers, Mostafa Baghbanzadeh, George M. Whitesides

Research output: Contribution to journalArticlepeer-review

75 Citations (Scopus)


This paper describes a physical-organic study of the effect of uncharged, polar, functional groups on the rate of charge transport by tunneling across self-assembled monolayer (SAM)-based large-area junctions of the form Ag TSS(CH2)nM(CH2)mT// Ga2O3/EGaIn. Here AgTS is a template-stripped silver substrate, -M- and -T are "middle" and "terminal" functional groups, and EGaIn is eutectic gallium-indium alloy. Twelve uncharged polar groups (-T = CN, CO2CH3, CF3, OCH 3, N(CH3)2, CON(CH3)2, SCH3, SO2CH3, Br, P(O)(OEt)2, NHCOCH3, OSi(OCH3)3), having permanent dipole moments in the range 0.5 < μ < 4.5, were incorporated into the SAM. A comparison of the electrical characteristics of these junctions with those of junctions formed from n-alkanethiolates led to the conclusion that the rates of charge tunneling are insensitive to the replacement of terminal alkyl groups with the terminal polar groups in this set. The current densities measured in this work suggest that the tunneling decay parameter and injection current for SAMs terminated in nonpolar n-alkyl groups, and polar groups selected from common polar organic groups, are statistically indistinguishable.

Original languageEnglish
Pages (from-to)16-19
Number of pages4
JournalJournal of the American Chemical Society
Issue number1
Publication statusPublished - 2014 Jan 8
Externally publishedYes

ASJC Scopus subject areas

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


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