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 investigatesthe 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 silverspherical nanoparticle seeds (Ag-Seeds) used critically influences the resulting Ag-NPlate characteristics. Decreasing the Ag-Seedconcentration induces an infrared shift in the main plasmon peak compared to pure Ag-Seeds, corresponding to increased NPlatesize. 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 sensingwas demonstrated by successfully detecting brilliant blue dye (BB) using surface-enhanced Raman spectroscopy (SERS) upon theirincorporation into an agarose gel.