Electron Transport through Self-Assembled Monolayers of Tripeptides

Evgeniy Mervinetsky, Israel Alshanski, Stephane Lenfant, David Guerin, Leonardo Medrano Sandonas, Arezoo Dianat, Rafael Gutierrez, Gianaurelio Cuniberti, Mattan Hurevich, Shlomo Yitzchaik, Dominique Vuillaume*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

12 Scopus citations

Abstract

We report how the electron transport through a solid-state metal/Gly-Gly-His (GGH) tripeptide monolayer/metal junction and the metal/GGH work function (WF) are modified by the GGH complexation with Cu2+ ions. Conducting atomic force microscopy is used to measure the current-voltage histograms. The WF is characterized by combining macroscopic Kelvin probe and Kelvin probe force microscopy at the nanoscale. We observe that the complexation of Cu2+ ions with the GGH monolayer is highly dependent on the molecular surface density and results in opposite trends. In the case of a high-density monolayer the conformational changes are hindered by the proximity of the neighboring peptides, hence forming an insulating layer in response to copper complexation. However, the monolayers of a slightly lower density allow for the conformational change to a looped peptide wrapping the Cu-ion, which results in a more conductive monolayer. Copper-ion complexation to the high- and low-density monolayers systematically induces an increase of the WFs. Copper-ion complexation to the low-density monolayer induces an increase of electron-transport efficiency, whereas the copper-ion complexation to the high-density monolayer results in a slight decrease of electron transport. Both of the observed trends agree with first-principle calculations. Complexation of copper to the low-density GGH monolayer induces a new gap state slightly above the Au Fermi energy that is absent in the high-density monolayer.

Original languageAmerican English
Pages (from-to)9600-9608
Number of pages9
JournalJournal of Physical Chemistry C
Volume123
Issue number14
DOIs
StatePublished - 11 Apr 2019

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Copyright © 2019 American Chemical Society.

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