Surface‐Enhanced Raman Spectroscopy (SERS): General Introduction

Abstract

Surface‐enhanced Raman scattering (SERS) was discovered in the mid‐1970s, by which the intrinsically low detection sensitivity of Raman spectroscopy is no longer a fatal disadvantage for this analytical tool. As a general introduction of SERS , the almost 40‐year history of SERS is first overviewed, showing that SERS has gone through a tortuous pathway to develop into a powerful diagnostic technique. We then describe the principle of SERS and enhancement mechanisms, illustrating that SERS is mainly surface plasmon resonance (SPR)‐ and nanostructure‐enhancement phenomenon. The SERS measurement procedures, in particular the preparation of various SERS active substrates, are discussed. On the basis of four important criteria in analytical science, i.e. detection sensitivity, (energetic, spatial, and temporal) resolution, generality, and reliability, we highlight two different approaches to utilize the strength and offset the weakness of SERS . With the enormously high sensitivity and spectral resolution, SERS has been applied successfully to surface analysis and trace analysis by gaining meaningful information from an extremely small quantity of species even down to single molecules. To significantly improve the surface generality and spatial resolution, tip‐enhanced Raman spectroscopy (TERS) was invented in 2000. To greatly improve the material generality and measurement reliability, shell‐isolated nanoparticle‐enhanced Raman spectroscopy (SHINERS) was introduced in 2010. Finally, prospective developments of SERS in substrates, methods, and theory are briefly discussed.

Core–Shell Nanoparticle-Enhanced Raman Spectroscopy

“…The giant enhancement in SERS could be primarily attributed to the enhancement of the local EM field in the vicinity of the nanostructures and attributed to the enhanced efficiency of irradiation of the nanostructures mainly due to LSPR. 225 In addition, five types of chemical effects may also contribute to the change of the relative and total Raman intensity, 245 (1) ground Here we concentrate the discussion on the EM enhancement mechanism of SERS by taking SERS on a gold nanosphere dimer as an example. EM enhancement in SERS is a two-step process.…”

Potential-Dependent Coadsorption of Pyridine Molecule and α-Pyridyl Radical at the Pt Electrode/Electrolyte Interface

“…In this work, we used an operando electrochemical surface-enhanced Raman spectroscopy (EC-SERS) method to study the coordination and reaction of pyridine at the Pt electrode/electrolyte interface. SERS is highly suitable to fulfill the above tasks due to its ultrahigh sensitivity, the capacity of detecting low-frequency vibrations, and the absence of interference from the solvent water. ,− In the following sections, we first verify the effects of pH and bulk concentration of pyridine on the surface-enhanced Raman spectra (SER spectra) to analyze the possible adsorption states of the interfacial pyridine species. Then, we combined the density functional theory (DFT) calculation and the isotopic labeling of pyridine to identify the coordination and configuration of pyridine species on the Pt electrode from which the adsorbed Py and α-Pyl are both confirmed.…”

High Sensitivity SERS Substrate of a Few Nanometers Single-Layer Silver Thickness Fabricated by DC Magnetron Sputtering Technology

“…The EM effect is in the proximity of the nanostructured surfaces, where coherent electrons oscillate around the surfaces or nanoscale crevices to excite the molecule's localized surface plasmon resonance (SPR). The EM coupling of the oscillating dipoles from the adsorbed analytes can mainly contribute to Raman enhancement on the metal surfaces [7]. Therefore, the SERS enhancement factor (EF), defined as the product of EM and CE, is described as EF = EM × CE.…”