Critical Role of Adsorption Equilibria on the Determination of Surface-Enhanced Raman Enhancement

Abstract

Surface-enhanced Raman spectroscopy (SERS) is a useful technique for probing analyte-noble metal interactions and determining thermodynamic properties such as their surface reaction equilibrium constants and binding energies. In this study, we measure the binding equilibrium constants and Gibbs free energy of binding for a series of nitrogen-containing aromatic molecules adsorbed on Klarite substrates. A dual Langmuir dependence of the SERS intensity on concentration was observed for the six species studied, indicating the presence of at least two different binding energies. We relate the measured binding energies to the previously described SERS enhancement value (SEV) and show that the SEV is proportional to the traditional SERS enhancement factor G, with a constant of proportionality that is critically dependent on the adsorption equilibrium constant determined from the dual Langmuir isotherm. We believe the approach described is generally applicable to many SERS substrates, both as a prescriptive approach to determining their relative performance and as a probe of the substrate's affinity for a target adsorbate.

Surface-plasmon-induced azo coupling reaction between nitro compounds on dendritic silver monitored by surface-enhanced Raman spectroscopy

“…Nanometer-sized plasmonic materials (i.e., silver, gold, and composites) exhibit unique chemical and physical properties that may nd use in various applications such as molecular sensing, catalysis, and optoelectronics. [1][2][3][4][5] Surface functionalization of nanostructured materials, which has become an important technique in nanotechnology and surface chemistry, can transform these plasmonic materials into valuable nished products. Plasmon-driven catalytic reactions have attracted attention in recent years because they create a new route for controlling catalytic reactions on metallic substrates.…”

Pollutant capturing SERS substrate: porous boron nitride microfibers with uniform silver nanoparticle decoration

“…[6][7][8][9][10][11][12] However, traditional SERS substrate is mainly based on metal nanostructures, such as Ag and Au, whose surface is hydrophilic 6,8,13 . 15,16 Therefore, how to concentrate target molecules on the near surface of SERS active substrate has become a critical challenge. 14 The intensity of SERS signal highly depends on the amount of molecules on the surface.…”

Probing ring contraction and decarboxylation of Rhodizonate and the influence of Cu (II) using surface‐enhanced Raman Scattering

“…[13,14,19] SERS spectroscopy has been shown to detect molecules even at singlemolecule regime, [20,21] as well as it has been applied to study, for example, the kinetics of surface coverage. [22,23] One advantage of the SERS approach is that the photoexcitation has not necessarily to be in resonance with the chemical species of interest, which decrease the chances or avoids lateral laser-induced photochemical reactions.…”