Bridging Theory and Experiment in Ag Nanoplates for SERS Substrates

ABSTRACT Silver nanostructures are extensively studied due to their unique properties and broad applicability. This work investigates the optical properties and field‐enhancement potential of silver nanoplates (Ag‐NPlates) synthesized via a two‐step method. Optical extinction spectroscopy (OES) combined with theoretical analysis characterized the suspensions’ size distribution, morphology, and spectral behavior, complemented by TEM analysis. Both techniques revealed that the concentration of silver spherical nanoparticle seeds (Ag‐Seeds) used critically influences the resulting Ag‐NPlate characteristics. Decreasing the Ag‐Seed concentration induces an infrared shift in the main plasmon peak compared to pure Ag‐Seeds, corresponding to increased NPlate size. Size distributions centered at edge lengths of 12–15 nm and 34–36 nm were observed, yielding plasmon peaks at 543 nm (higher seed concentration) and 815 nm (lower seed concentration), respectively. Furthermore, the Ag‐NPlates utility for sensing was demonstrated by successfully detecting brilliant blue dye (BB) using surface‐enhanced Raman spectroscopy (SERS) upon their incorporation into an agarose gel.