Electron Transport through Self-Assembled Monolayers of Tripeptides

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 W...

Full description

Saved in:
Bibliographic Details
Published in:Journal of physical chemistry. C 2019-04, Vol.123 (14), p.9600-9608
Main Authors: Mervinetsky, Evgeniy, Alshanski, Israel, Lenfant, Stephane, Guerin, David, Medrano Sandonas, Leonardo, Dianat, Arezoo, Gutierrez, Rafael, Cuniberti, Gianaurelio, Hurevich, Mattan, Yitzchaik, Shlomo, Vuillaume, Dominique
Format: Article
Language:English
Subjects:
Condensed Matter
Mesoscopic Systems and Quantum Hall Effect
Physics
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary: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.
ISSN:1932-7447
1932-7455
DOI:10.1021/acs.jpcc.9b01082