SERS of Individual Nanoparticles on a Mirror: Size Does Matter, but so Does Shape

Felix Benz, Rohit Chikkaraddy, Andrew Salmon, Hamid Ohadi, Bart de Nijs, Jan Mertens, Cloudy Carnegie, Richard W. Bowman, Jeremy J. Baumberg

Research output: Contribution to journalArticle

65 Citations (Scopus)

Abstract

Coupling noble metal nanoparticles by a 1 nm gap to an underlying gold mirror confines light to extremely small volumes, useful for sensing on the nanoscale. Individually measuring 10 000 of such gold nanoparticles of increasing size dramatically shows the different scaling of their optical scattering (far-field) and surface-enhanced Raman emission (SERS, near-field). Linear red-shifts of the coupled plasmon modes are seen with increasing size, matching theory. The total SERS from the few hundred molecules under each nanoparticle dramatically increases with increasing size. This scaling shows that maximum SERS emission is always produced from the largest nanoparticles, irrespective of tuning to any plasmonic resonances. Changes of particle facet with nanoparticle size result in vastly weaker scaling of the near-field SERS, without much modifying the far-field, and allows simple approaches for optimizing practical sensing.
Original languageEnglish
Pages (from-to)2264-2269
Number of pages6
JournalJournal of Physical Chemistry Letters
Volume7
Issue number12
Early online date25 May 2016
DOIs
Publication statusPublished - 16 Jun 2016

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    Benz, F., Chikkaraddy, R., Salmon, A., Ohadi, H., Nijs, B. D., Mertens, J., Carnegie, C., Bowman, R. W., & Baumberg, J. J. (2016). SERS of Individual Nanoparticles on a Mirror: Size Does Matter, but so Does Shape. Journal of Physical Chemistry Letters, 7(12), 2264-2269. https://doi.org/10.1021/acs.jpclett.6b00986