Issue 7, 2024

‘When is a hotspot a good nanospot’ – review of analytical and hotspot-dominated surface enhanced Raman spectroscopy nanoplatforms

Abstract

Substrate development in surface-enhanced Raman spectroscopy (SERS) continues to attract research interest. In order to determine performance metrics, researchers in foundational SERS studies use a variety of experimental means to characterize the nature of substrates. However, often this process would appear to be performed indiscriminately without consideration for the physical scale of the enhancement phenomena. Herein, we differentiate between SERS substrates whose primary enhancing structures are on the hundreds of nanometer scale (analytical SERS nanosubstrates) and those whose main mechanism derives from nanometric-sized gaps (hot-spot dominated SERS substrates), assessing the utility of various characterization methods for each substrate class. In this context, characterization approaches in white-light spectroscopy, electron beam methods, and scanning probe spectroscopies are reviewed. Tip-enhanced Raman spectroscopy, wavelength-scanned SERS studies, and the impact of surface hydrophobicity are also discussed. Conclusions are thus drawn on the applicability of each characterization technique regarding amenability for SERS experiments that have features at different length scales. For instance, while white light spectroscopy can provide an indication of the plasmon resonances associated with 10 s–100 s nm-scale structures, it may not reveal information about finer surface texturing on the true nm-scale, critical for SERS’ sensitivity, and in need of investigation via scanning probe techniques.

Graphical abstract: ‘When is a hotspot a good nanospot’ – review of analytical and hotspot-dominated surface enhanced Raman spectroscopy nanoplatforms

Article information

Article type
Review Article
Submitted
22 okt 2023
Accepted
13 jan 2024
First published
17 jan 2024
This article is Open Access
Creative Commons BY license

Nanoscale, 2024,16, 3293-3323

‘When is a hotspot a good nanospot’ – review of analytical and hotspot-dominated surface enhanced Raman spectroscopy nanoplatforms

M. Hardy and P. Goldberg Oppenheimer, Nanoscale, 2024, 16, 3293 DOI: 10.1039/D3NR05332F

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