Demonstrating photoluminescence from Au is electronic inelastic light scattering of a plasmonic metal: the origin of SERS backgrounds.

James T Hugall,Jeremy J Baumberg

doi:10.1021/acs.nanolett.5b00146

James T Hugall, Jeremy J Baumberg

Open Access

https://doi.org/10.1021/acs.nanolett.5b00146

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Journal: Nano letters	Publication Date: Mar 9, 2015
Citations: 186	License type: cc-by

Affiliation: University of Cambridge

Abstract

Temperature-dependent surface-enhanced Raman scattering (SERS) is used to investigate the photoluminescence and background continuum always present in SERS but whose origin remains controversial. Both the Stokes and anti-Stokes background is found to be dominated by inelastic light scattering (ILS) from the electrons in the noble metal nanostructures supporting the plasmon modes. The anti-Stokes background is highly temperature dependent and is shown to be related to the thermal occupation of electronic states within the metal via a simple model. This suggests new routes to enhance SERS sensitivities, as well as providing ubiquitous and calibrated real-time temperature measurements of nanostructures.

Highlights

The field of surface-enhanced Raman scattering (SERS) has been hindered by the complexity and irreproducibility of spectra produced from differently designed plasmonic nanostructures which support several different enhancement mechanisms
Our results critically suggest that new methods may be needed to suppress inelastic light scattering (ILS) components to the SERS background in order to provide the full benefit of SERS enhancements in molecular sensing
While it is clear that light emission from plasmonic structures is enhanced at plasmonic resonances,[4,16] this merely accounts for enhancing the coupling of light in and out of the metal, and a proposed mechanism suggesting resonant transfer between excited electron and plasmon is not possible for ω < ωIB

Summary

Introduction

The field of surface-enhanced Raman scattering (SERS) has been hindered by the complexity and irreproducibility of spectra produced from differently designed plasmonic nanostructures which support several different enhancement mechanisms. We show that a strong component of this background arises from the inelastic light scattering (ILS) of electrons inside the plasmonic nanostructures.

Results

Conclusion