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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.
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
URL: https://doi.org/10.1021/jacs.1c09549
DOI: 10.1021/jacs.1c09549
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