Molecular rectification in a metal-insulator-metal junction based on self-assembled monolayers

Michael L. Chabinyc, Xiaoxi Chen, R. Erik Holmlin, Heiko Jacobs, Hjalti Skulason, C. Daniel Frisbie, Vladimiro Mujica, Mark A. Ratner, Maria Anita Rampi, George M. Whitesides

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227 Scopus citations

Abstract

An electrical junction formed by mechanical contact between two self-assembled monolayers (SAMs)-a SAM formed from an dialkyl disulfide with a covalently linked tetracyanoquinodimethane group that is supported by silver (or gold) and a SAM formed from an alkanethiolate SAM that is supported by mercury-rectifies current. The precursor to the SAM on silver (or gold) was bis(20-(2-((2,5-cyclohexadiene- 1,4-diylidene)dimalonitrile))decyl)) disulfide and that for the SAM on mercury was HS(CH2)n-1CH3 (n = 14, 16, 18). The electrical properties of the junctions were characterized by current-voltage measurements. The ratio of the conductivity of the junction in the forward bias (Hg cathodic) to that in the reverse bias (Hg anodic), at a potential of 1 V, was, 9 ± 2 when the SAM on mercury was derived from HS(CH2)15CH3. The ratio of the conductivity in the forward bias to that in the reverse bias increased with decreasing chain length of the alkanethiol used to form the SAM on mercury. These results demonstrate that a single redox center asymmetrically placed in a metal-insulator-metal junction can cause the rectification of current and indicate that a fixed dipole in the insulating region of a metal-insulator-metal junction is not required for rectification.

Original languageEnglish (US)
Pages (from-to)11730-11736
Number of pages7
JournalJournal of the American Chemical Society
Volume124
Issue number39
DOIs
StatePublished - Oct 2 2002

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