Adsorption of organic molecules on metal nanostructures: State of the art in SERS spectroscopy

Surface-enhanced Raman spectroscopy (VIS-SERS, FT-SERS) and surface enhanced Raman microprobe spectroscopy (micro-SERS) of molecules adsorbed on metal nanostructures is reviewed. Advantages and applications of these surface vibrational spectroscopic methods particularly for in situ study of the chemical identity, structure, orientation, chemical and electrochemical reaction of anions, surfactants, environmental pollutants, biomolecules and dye molecules adsorbed on charged Ag metal surfaces are discussed. Different applications show that these spectroscopic techniques are a powerful in situ method to study the liquid/solid interface and characterize self-assembled monolayers (SAMs) at high resolution. Moreover, the high enhancement factor of the surface Raman scattering intensity creates a new technique for obtaining vibrational spectra of organic and inorganic molecules from dilute aqueous solutions down to 10−14 mol dm−3. Micro-SERS spectroscopy permits the acquisition of surface Raman spectra from substance spots down to 1 µm in size or other forms of microsamples approaching the femtogram level.