Towards molecular electronic devices based on 'all-carbon' wires


Moneo, Andrea, Gonzalez-Orive, Alejandro, Bock, Soren, Fenero, Marta, Herrer, I Lucia, Milan, David C ORCID: 0000-0002-2077-7920, Lorenzoni, Matteo, Nichols, Richard J ORCID: 0000-0002-1446-8275, Cea, Pilar, Perez-Murano, Francesc et al (show 2 more authors) (2018) Towards molecular electronic devices based on 'all-carbon' wires. NANOSCALE, 10 (29). pp. 14128-14138.

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Abstract

Nascent molecular electronic devices based on linear 'all-carbon' wires attached to gold electrodes through robust and reliable C-Au contacts are prepared via efficient in situ sequential cleavage of trimethylsilyl end groups from an oligoyne, Me<sub>3</sub>Si-(C[triple bond, length as m-dash]C)<sub>4</sub>-SiMe<sub>3</sub> (1). In the first stage of the fabrication process, removal of one trimethylsilyl (TMS) group in the presence of a gold substrate, which ultimately serves as the bottom electrode, using a stoichiometric fluoride-driven process gives a highly-ordered monolayer, Au|C[triple bond, length as m-dash]CC[triple bond, length as m-dash]CC[triple bond, length as m-dash]CC[triple bond, length as m-dash]CSiMe<sub>3</sub> (Au|C<sub>8</sub>SiMe<sub>3</sub>). In the second stage, treatment of Au|C<sub>8</sub>SiMe<sub>3</sub> with excess fluoride results in removal of the remaining TMS protecting group to give a modified monolayer Au|C[triple bond, length as m-dash]CC[triple bond, length as m-dash]CC[triple bond, length as m-dash]CC[triple bond, length as m-dash]CH (Au|C<sub>8</sub>H). The reactive terminal C[triple bond, length as m-dash]C-H moiety in Au|C<sub>8</sub>H can be modified by 'click' reactions with (azidomethyl)ferrocene (N<sub>3</sub>CH<sub>2</sub>Fc) to introduce a redox probe, to give Au|C<sub>6</sub>C<sub>2</sub>N<sub>3</sub>HCH<sub>2</sub>Fc. Alternatively, incubation of the modified gold substrate supported monolayer Au|C<sub>8</sub>H in a solution of gold nanoparticles (GNPs), results in covalent attachment of GNPs on top of the film via a second alkynyl carbon-Au σ-bond, to give structures Au|C<sub>8</sub>|GNP in which the monolayer of linear, 'all-carbon' C<sub>8</sub> chains is sandwiched between two macroscopic gold contacts. The covalent carbon-surface bond as well as the covalent attachment of the metal particles to the monolayer by cleavage of the alkyne C-H bond is confirmed by surface-enhanced Raman scattering (SERS). The integrity of the carbon chain in both Au|C<sub>6</sub>C<sub>2</sub>N<sub>3</sub>HCH<sub>2</sub>Fc systems and after formation of the gold top-contact electrode in Au|C<sub>8</sub>|GNP is demonstrated through electrochemical methods. The electrical properties of these nascent metal-monolayer-metal devices Au|C<sub>8</sub>|GNP featuring 'all-carbon' molecular wires were characterised by sigmoidal I-V curves, indicative of well-behaved junctions free of short circuits.

Item Type: Article
Depositing User: Symplectic Admin
Date Deposited: 03 Sep 2018 06:16
Last Modified: 19 Jan 2023 01:25
DOI: 10.1039/c8nr02347f
Open Access URL: https://pubs.rsc.org/en/Content/ArticleLanding/201...
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URI: https://livrepository.liverpool.ac.uk/id/eprint/3025782
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