Effect of Foreign Molecules on the SERS of Probe Molecules Trapped in Gaps between Planar Ag and Nano-sized Ag Particles

Abstract

A few years ago, the plasmon-induced electronic coupling (PIEC) model was proposed in the literature to explain small changes in the surface-enhanced Raman scattering (SERS) in nanogap systems. If this model is correct, it will be very helpful in both basic and application fields. In light of this, we carefully reexamined its appropriateness. Poly(4-vinylpyridine) (P4VP) used in the earlier work was, however, never a proper layer, since most adsorbates not only adsorbed onto Ag nanoparticles sitting on P4VP but also penetrated into the P4VP layer deposited initially onto a flat Ag substrate, ultimately ending up in the SERS hot sites. Using 1,4-phenylenediisocyanide and 4-nitrophenol as the affixing layer and the foreign adsorbate, respectively, we could clearly reveal that the PIEC model is not suited for explaining the Raman signal in a nanogap system. Most of the Raman signal must have arisen from molecules situated at the gap center.

Role of silica-based porous cellulose nanocrystals in improving water absorption and mechanical properties

“…The number of nano-size molecules in a polymer composition can significantly improve its mechanical properties (Abbasi et al, 2023;Arshad et al, 2023;Munir et al, 2023). This is mostly due to the nanoparticle's exclusive holdings, which result in effective development properties (Kim et al, 2013;Longmire et al, 2008;Ullah et al, 2021b). Polymer nanocomposites are materials in which at least one dimension of the matrix is strengthened by particles (Aziz et al, 2021a;Aziz et al, 2021d;Chen et al, 2019a).…”