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

Richard Brooke, Douglas Szumski, Andrea Vezzoli, Simon Higgins, Richard Nichols, Walther Schwarzacher*

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

19 Citations (Scopus)
351 Downloads (Pure)

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.

Original languageEnglish
Pages (from-to)1317-1322
Number of pages6
JournalNano Letters
Volume18
Issue number2
Early online date22 Jan 2018
DOIs
Publication statusPublished - 14 Feb 2018

Keywords

  • Break-junction
  • electron transfer
  • fluctuations
  • molecular electronics
  • protonation
  • sensors

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