Synthesis of SiO₂@Ag Nanocomposite for Investigating Metal-Enhanced Fluorescence and Surface-Enhanced Raman Spectroscopy

SiO₂@Ag nanocomposite (NC) has been synthesized by the chemical reduction and Stӧber method for Metal-enhanced fluorescence (MEF) of Rhodmine 6G (R6G) and Surface-enhanced Raman spectroscopy (SERS) of Malachite green (MG). As-synthesized SiO₂@Ag NC indicated SiO₂ nanosphere (NS) and Ag nanoparticle (NP) morphologies. The SiO₂@Ag NC was high quality with a well-defined crystallite phase with average sizes of 24 nm and 132 nm for Ag NP and SiO₂ NC, respectively. By using SiO₂@Ag NC, the photoluminescence (PL) intensity of the R6G (at 59.17 ppm) was increased approximately 133 times. The SERS of the MG (at 1.0 ppm) with SiO₂@Ag NC as substrate clearly observed vibrational modes in MG dye at 798, 916, 1172, 1394, and 1616 cm^-1. As a result, the SERS enhancement factor (EF_SERS) at 1172 cm^-1 obtained 6.3 × 10⁶. This initial study points to the potential of SiO₂@Ag NC as a promising material for MEF and SERS substrates to detect dyes at low concentrations.