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Role of Order in the Mechanism of Charge Transport across Single-Stranded and Double-Stranded DNA Monolayers in Tunnel Junctions

Lookup NU author(s): Dr Eimer TuiteORCiD, Dr Andrew Pike



This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND).


Deoxyribonucleic acid (DNA) has been hypothesized to act as a molecular wire due to the presence of an extended π-stack between base pairs, but the factors that are detrimental in the mechanism of charge transport (CT) across tunnel junctions with DNA are still unclear. Here we systematically investigate CT across dense DNA monolayers in large-area biomolecular tunnel junctions to determine when intrachain or interchain CT dominates and under which conditions the mechanism of CT becomes thermally activated. In our junctions, double-stranded DNA (dsDNA) is 30-fold more conductive than single-stranded DNA (ssDNA). The main reason for this large change in conductivity is that dsDNA forms ordered monolayers where intrachain tunneling dominates, resulting in high CT rates. By varying the temperature T and the length of the DNA fragments in the junctions, which determines the tunneling distance, we reveal a complex interplay between T, the length of DNA, and structural order on the mechanism of charge transport. Both the increase in the tunneling distance and the decrease in structural order result in a change in the mechanism of CT from coherent tunneling to incoherent tunneling (hopping). Our results highlight the importance of the interplay between structural order, tunneling distance, and temperature on the CT mechanism across DNA in molecular junctions.

Publication metadata

Author(s): Gupta NK, Wilkinson EA, Karuppannan SK, Bailey L, Vilan A, Zhang Z, Qi D-C, Tadich A, Tuite EM, Pike AR, Tucker JHR, Nijhuis CA

Publication type: Article

Publication status: Published

Journal: Journal of the American Chemical Society

Year: 2021

Volume: 143

Issue: 48

Pages: 20309-20319

Print publication date: 08/12/2021

Online publication date: 26/11/2021

Acceptance date: 26/11/2021

Date deposited: 16/01/2022

ISSN (print): 0002-7863

ISSN (electronic): 1520-5126

Publisher: American Chemical Society


DOI: 10.1021/jacs.1c09549


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Funder referenceFunder name
778001Commission of the European Communities