Gold dimer nanoantenna with slanted gap for tunable LSPR and improved SERS

Abstract
We focus on improving the surface-enhanced Raman scattering (SERS) of dimer nanoantenna by tailoring the shape of the coupled nanoantennas extremities from rounded to straight or slanted ones. A numerical model based on the discrete dipole approximation method-taking into account periodicity, adhesion layer, and roughness-is first validated by comparison with localized surface plasmon resonance (LSPR) and SERS experiments on round-edged dimer nanoantennas and then used to investigate the effect of the straight or slanted gap in the dimer antenna. Simulations show that both LSPR and SERS can be tuned by changing the gap slanting angle. The SERS enhancement factor can also be improved by 2 orders of magnitude compared to the one reached using a rounded gap. Therefore, the slanting angle can be used as a new control parameter in the design of SERS substrates to guarantee stronger field confinement and higher sensitivity, especially as its feasibility is demonstrated. © 2014 American Chemical Society.

Citation
Kessentini, S., Barchiesi, D., D’Andrea, C., Toma, A., Guillot, N., Di Fabrizio, E., … Lamy de la Chapelle, M. (2014). Gold Dimer Nanoantenna with Slanted Gap for Tunable LSPR and Improved SERS. The Journal of Physical Chemistry C, 118(6), 3209–3219. doi:10.1021/jp409844y

Acknowledgements
The authors thank the Nanoantenna European Project (FP7 Health-F5-2009-241818), the Region Champagne-Ardennes, the Conseil Regional de l'Aube, and MIUR (Project PRIN 2008J858Y7 and Programma Operativo Nazionale Ricerca e Competitivita 2007-2013, PON01_01322 PANREX) for financial support.

Publisher
American Chemical Society (ACS)

Journal
The Journal of Physical Chemistry C

DOI
10.1021/jp409844y

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