Surface modifications of nanomaterials used for surface-enhanced Raman scattering measurements

The efficiency of generating a Raman signal from molecules adsorbed on certain surfaces can be increased by many orders of magnitude - an effect known as surface-enhanced Raman scattering (SERS). Substrates for SERS measurements are often coated with layers of other materials. This increases the distance between the molecules of the analyte and the plasmonic nanostructure, which usually decreases a SERS enhancement factor. Nevertheless, such coatings can generate new, important functions of SERS nanomaterials (selective capture of certain analytes, the possibility of recording SERS spectra on layers of metals that do not generate a SERS effect themselves, etc.). This review presents selected methods currently used to modify SERS substrate surfaces (e.g.: deposition of layers of other metals, deposition of layers of oxides, attachment of macromolecules), and discusses some of the new possibilities these modifications offer.