Electron Transport through Self-Assembled Monolayers of Tripeptides

Evgeniy Mervinetsky , Israel Alshanski , Stéphane Lenfant (1, 2) , David Guérin (3) , L. Medrano Sandonas , Arezoo Dianat , Israel Yitzchaik , Rafael Gutierrez , Gianaurelio Cuniberti (4) , Israel Hurevich , S. Yitzchaik , Dominique Vuillaume (1, 2)

1 IEMN - Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520
2 NCM - IEMN - Nanostructures, nanoComponents & Molecules - IEMN
3 CTP
4 IFW Dresden - Leibniz Institute for Solid State and Materials Research

We report how the electron transport through a solid-state metal/Gly-Gly-His tripeptide (GGH) monolayer/metal junction and the metal/GGH work function are modified by the GGH complexation with Cu2+ ions. Conducting AFM is used to measure the current-voltage histograms. The work function is characterized by combining macroscopic Kelvin probe and Kelvin probe force microscopy at the nanoscale. We observe that the Cu2+ ions complexation 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. Whereas the slightly lower density monolayers 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 work functions. Copper-ion complexation to the low-density monolayer induces an increase of electron transport efficiency, while the copper-ion complexation to the high-density monolayer results in a slight decrease of electron transport. Both of the observed trends are in agreement with first-principle calculations. Complexed copper to low density GGH-monolayer induces a new gap state slightly above the Au Fermi energy that is absent in the high density monolayer.

Domaines: Physique [physics]; Systèmes mésoscopiques et effet Hall quantique [cond-mat.mes-hall]

Evgeniy Mervinetsky, Israel Alshanski, Stéphane Lenfant, David Guérin, L. Medrano Sandonas, et al.. Electron Transport through Self-Assembled Monolayers of Tripeptides. Journal of Physical Chemistry C, 2019, 123 (14), pp.9600-9608. ⟨10.1021/acs.jpcc.9b01082⟩. ⟨hal-02128012⟩