Plasmonic tunnel junctions for single-molecule redox chemistry

de Nijs, Bart and Benz, Felix and Barrow, Steven J. and Sigle, Daniel O. and Chikkaraddy, Rohit and Palma, Aniello and Carnegie, Cloudy and Kamp, Marlous and Sundararaman, Ravishankar and Narang, Prineha and Scherman, Oren A. and Baumberg, Jeremy J. (2017) Plasmonic tunnel junctions for single-molecule redox chemistry. Nature Communications, 8 . ISSN 2041-1723. (doi:https://doi.org/10.1038/s41467-017-00819-7) (Full text available)

Abstract

Nanoparticles attached just above a flat metallic surface can trap optical fields in the nanoscale gap. This enables local spectroscopy of a few molecules within each coupled plasmonic hotspot, with near thousand-fold enhancement of the incident fields. As a result of non-radiative relaxation pathways, the plasmons in such sub-nanometre cavities generate hot charge carriers, which can catalyse chemical reactions or induce redox processes in molecules located within the plasmonic hotspots. Here, surface-enhanced Raman spectroscopy allows us to track these hot-electron-induced chemical reduction processes in a series of different aromatic molecules. We demonstrate that by increasing the tunnelling barrier height and the dephasing strength, a transition from coherent to hopping electron transport occurs, enabling observation of redox processes in real time at the single-molecule level.

Item Type: Article
Subjects: Q Science > QC Physics > QC176.8.N35 Nanoscience, nanotechnology
Q Science > QC Physics > QC355 Optics
Q Science > QD Chemistry > QD431 Organic Chemistry- Biochemistry- Proteins, peptides, amino acids
Divisions: Faculties > Sciences > School of Physical Sciences
Faculties > Sciences > School of Physical Sciences > Functional Materials Group
Depositing User: Aniello Palma
Date Deposited: 22 Nov 2017 11:13 UTC
Last Modified: 23 Nov 2017 12:35 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/64608 (The current URI for this page, for reference purposes)
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