TY - JOUR
T1 - Role of Order in the Mechanism of Charge Transport across Single-Stranded and Double-Stranded DNA Monolayers in Tunnel Junctions
AU - Gupta, Nipun Kumar
AU - Wilkinson, Edward A.
AU - Karuppannan, Senthil Kumar
AU - Bailey, Lily
AU - Vilan, Ayelet
AU - Zhang, Ziyu
AU - Qi, Dong Chen
AU - Tadich, Anton
AU - Tuite, Eimer M.
AU - Pike, Andrew R.
AU - Tucker, James H.R.
AU - Nijhuis, Christian A.
N1 - Funding Information:
Dr. Bruce Cowie and Australian Synchrotron, and the Singapore Synchrotron Light Source are acknowledged for assistance with the photoelectron spectroscopy measurements. Funding by the Ministry of Education (MOE) for supporting this research under Award No. MOE2019-T2-1-137 and R-143-000-B30-112 are acknowledged. Prime Minister’s Office, Singapore under its Medium sized centre program is also acknowledged for supporting this research. The Centre for Chemical and Materials Analysis in the School of Chemistry at the University of Birmingham is acknowledged for technical support. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie Grant Agreement No. 778001.
Publisher Copyright:
© 2021 The Authors. Published by American Chemical Society.
PY - 2021/12/8
Y1 - 2021/12/8
N2 - 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.
AB - 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.
KW - UT-Hybrid-D
UR - http://www.scopus.com/inward/record.url?scp=85120608599&partnerID=8YFLogxK
U2 - 10.1021/jacs.1c09549
DO - 10.1021/jacs.1c09549
M3 - Article
C2 - 34826219
AN - SCOPUS:85120608599
SN - 0002-7863
VL - 143
SP - 20309
EP - 20319
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
IS - 48
ER -