Specific behavior of the p-aminothiophenol – Silver sol system in their Ultra-Violet–Visible (UV–Visible) and Surface Enhanced Raman (SERS) spectra

FDTD Simulations for Rhodium and Platinum Nanoparticles for UV Plasmonics

The article describes the results of finite-difference time-domain (FDTD) mathematical modeling of electromagnetic fields distortion near the surfaces of two transition metals: rhodium (Rh) and platinum (Pt) on glass (SiO₂) substrates. Results were compared with calculated optical properties of classical SERS generating metals (Au and Ag). We have performed FDTD-based theoretical calculations for UV SERS-active nanoparticles (NPs) and structures based on hemispheres of Rh and Pt and planar surfaces, consisting of single NPs with varied gaps between them. The results have been compared with gold stars, silver spheres and hexagons. The prospects of the theoretical approach for single NPs and planar surfaces modeling to evaluate optimal field amplification and light scattering parameters have been shown. The presented approach could be applied as a basis for performing the methods of controlled synthesis for LPSR tunable colloidal and planar metal-based biocompatible optical sensors for UV and deep-UV plasmonics. The difference between UV-plasmonic NPs and plasmonics in a visible range has been evaluated.

Plasmon-Mediated Surface Engineering of Silver Nanowires for Surface-Enhanced Raman Scattering

We reveal nanoscale morphological changes on the surface of a silver nanowire (AgNW) in the conventional surface-enhanced Raman scattering (SERS) measurement condition. The surface morphology changes are due to the surface plasmon-mediated photochemical etching of silver in the presence of certain Raman probes, resulting in a dramatic increase of Raman scattering intensity. This observation indicates that the measured SERS enhancement does not always originate from the as-designed/fabricated structures themselves, but sometimes with contribution from the morphological changes by plasmon-mediated photochemical reactions. Our work provides a guideline for more reliable SERS measurements and demonstrates a novel method for simple and site-specific engineering of SERS substrate and AgNW probes for designing and fabricating new SERS systems, stable and efficient TERS mapping, and single-cell SERS endoscopy.

Ultra-thin Au tip structure: a novel SERS substrate for in situ observation of a p-aminothiophenol surface-catalytic reaction

In situ observation of a p-aminothiophenol surface-catalytic reaction on a novel Au nano-tip structured SERS substrate.