Dual Control of Molecular Conductance through pH and Potential in Single-Molecule Devices



Brooke, Richard J, Szumski, Doug S, Vezzoli, Andrea ORCID: 0000-0002-8059-0113, Higgins, Simon J ORCID: 0000-0003-3518-9061, Nichols, Richard J ORCID: 0000-0002-1446-8275 and Schwarzacher, Walther
(2018) Dual Control of Molecular Conductance through pH and Potential in Single-Molecule Devices. NANO LETTERS, 18 (2). pp. 1317-1322.

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Abstract

One of the principal aims of single-molecule electronics is to create practical devices out of individual molecules. Such devices are expected to play a particularly important role as novel sensors thanks to their response to wide ranging external stimuli. Here we show that the conductance of a molecular junction can depend on two independent stimuli simultaneously. Using a scanning tunnelling microscope break-junction technique (STM-BJ), we found that the conductance of 4,4'-vinylenedipyridine (44VDP) molecular junctions with Ni contacts depends on both the electrochemically applied gate voltage and the pH of the environment. Hence, not only can the Ni|44VDP|Ni junction function as a pH-sensitive switch, but the value of the pH at which switching takes place can be tuned electrically. Furthermore, through the simultaneous control of pH and potential the STM-BJ technique delivers unique insight into the acid-base reaction, including the observation of discrete proton transfers to and from a single molecule.

Item Type: Article
Uncontrolled Keywords: Break-junction, molecular electronics, electron transfer, sensors, protonation, fluctuations
Depositing User: Symplectic Admin
Date Deposited: 12 Sep 2018 06:56
Last Modified: 19 Jan 2023 01:18
DOI: 10.1021/acs.nanolett.7b04995
Related URLs:
URI: https://livrepository.liverpool.ac.uk/id/eprint/3026134