Surface-Enhanced Raman Scattering with Nanomaterials

Abstract

Surface-enhanced Raman scattering (SERS) is a powerful analytical technique that enhances the Raman scattering signal from molecules adsorbed on or in close proximity to the metal surface. It is possible owing to localized surface plasmon resonance occurring in nanostructures metal surfaces. There are two commonly considered mechanisms for SERS, electromagnetic and chemical enhancement. The electromagnetic theory emphasizes that the Raman enhancements for adsorbates on particular surfaces occur because of the enhancement in electric field provided by the surface. When the incident light strikes the surfaces, surface plasmons can be excited by radiation, resulting in enhanced electromagnetic fields close to the surface. The chemical theory is thought to involve the creation of new electronic states and the formation of charge transfer complexes in some special cases between the chemisorbed species and the SERS active substrates, resulting in an enhanced Raman cross section of the molecules. This chapter describes the SERS activities of quinone derivatives by plasmonic silver nanoparticles and pollutant detection using gold nanoparticles. SERS studies of 2-bromo-1,4-naphthoquinone and 2,3-dibromo-1,4-naphthoquinone on prepared nanoparticles are described. SERS analysis of polluted soil is also discussed. The orientation of the above molecules on silver nanoparticles was elucidated from the spectral analysis