Chemical Interface Damping-Induced Attenuation of Surface Plasmon-Enhanced Raman Spectroscopy

Abstract

More molecules mean a stronger signal for surface-enhanced Raman spectroscopy (SERS), as usually expected. However, this is not always true in many cases. The factual molecular concentration dependence of the SERS intensity has always been controversial and confusing. Here, we present a chemical interface damping (CID)-induced SERS signal attenuation mechanism to reveal it based on electromagnetic theory and experimentally demonstrate its validity. It has been revealed that the SERS intensity is the result of competition between the two opposite effects of molecular adsorption-induced Raman scattering centers and CID, but not necessarily increasing with the rising concentration, especially at a relatively high concentration. When the molecular adsorption-induced CID is strong enough, the SERS intensity shows a nonmonotonic concentration dependence, while the weak CID leads to the monotonic concentration dependence under optimal excitation. In addition, the excitation condition also significantly influences the concentration dependence of the SERS intensity. When an excitation wavelength significantly deviates from the local surface plasmon resonance of the SERS substrate, the SERS intensity will increase monotonously with the rising concentration, even in the case of the strong CID, despite the reduced overall signal intensity. This work not only deepens the understanding of the electromagnetic enhancement mechanism in SERS, which is also of significance in the quantitative analyses, but also is suitable for the other plasmon-enhanced molecular spectroscopies.

Sensitive, Stable, and Recyclable ZnO/Ag Nanohybrid Substrates for Surface-Enhanced Raman Scattering Metrology

“…By using the 1622.50 cm –1 peak as the index, it is evident that ZnO/Ag nanohybrid greatly boosted Raman peak intensity, showing a maximum for the 15 AZ sample, which is attributed to the strong LSPR results from the increase in the number of hot spots, as discussed above . It can be explained based on the electromagnetic and charge transfer mechanism enhancements of the SERS signals . Moreover, when two Ag NCs approach each other, the electromagnetic field is magnified dramatically due to numerous SERS hot spots .…”

“…57 Moreover, when two Ag NCs approach each other, the electromagnetic field is magnified dramatically due to numerous SERS hot spots. 57 Apart from that, the 0 AZ sample shows a minor enhancement in the SERS signal, which may be attributed to the charge transfer of electrons from the ZnO to the LUMO of the methylene blue molecule. This charge transfer process can lead to changes in the vibrational Validating the reproducibility of SERS signals and substrate stability is necessary to obtain a good and multifunctional SERS platform.…”

“…20 It can be explained based on the electromagnetic and charge transfer mechanism enhancements of the SERS signals. 57 Moreover, when two Ag NCs approach each other, the electromagnetic field is magnified dramatically due to numerous SERS hot spots. 57 Apart from that, the 0 AZ sample shows a minor enhancement in the SERS signal, which may be attributed to the charge transfer of electrons from the ZnO to the LUMO of the methylene blue molecule.…”

Potential-Modulated Surface-Enhanced Raman Spectroscopy of Tolmetin at Gold Nanoparticle Film Functionalized Polarizable Liquid–Liquid Interfaces

“…Modeling of these phenomena implies an attenuation of surface plasmons by molecules adsorbed on metal nanoparticles, known as chemical interface damping (CID), and is associated with a change in the adsorption regime when moving from a monolayer to a multilayer of molecules. 53 To probe the limits of the use of potential-modulated SERS at an interfacial AuNP film as a quantitative tool, we measured the Raman intensity of a characteristic peak of tolmetin at 792 cm −1 (highlighted in blue in Figure 4A−C) that did not disappear or undergo a chemical shift when the interfacial polarization was changed. DFT calculations show that this peak is principally due to a phenyl ring symmetric deformation, see Table S1, Supporting Information.…”

Antielectric Potential Synthesis of Plasmonic Au–Ag Multidimensional Dimers Array for High-Resolution Encrypted Information

“…With the increase in diversity and complexity of information, it is important to improve the information carrier to cope with rapid and frequent information delivery. Optical-based information carriers or chips have the advantages of large capacity, , multidimensionality, , and high-security coefficient, , which attracts extensive attention in the fields of information storage, encryption, , optical sensing, , etc. This technology not only requires miniaturization of information carriers but also demands accurate information expression with high resolution.…”