Synthesis, Characterization, and applications of Silver Nanoparticles (Ag-NPs) as Surface-enhanced Raman Spectroscopy (SERS) substrate

Raman Spectroscopy (RS) has applications in the analysis of various pharmaceutical and food samples. But by using nanoparticles, the plasmonic applications and signal enhancement of RS are enhanced and thus called Surface-enhanced Raman spectroscopy (SERS). Silver nanoparticles (Ag-NPs) are utilized for this purpose because, in contrast to gold nanoparticles (Au-NPs), greater enhancement of signals are seen during utilizing as SERS substrate. The synthesis procedure of Ag-NPs is more cost-effective and requires less labor than Au-NPs when utilizing the chemical reduction method. During the synthesis of Ag-NPs, silver nitrate AgNO3 was reduced by using trisodium citrate Na3C6H5O7 act as both reducing and capping agents. After the characterization of Ag-NPs, the ideal size of Ag-NPs was reported in the range of 25-45 nm. Ideally, the signals were enhanced, and thus, the peaks of spectra were also clarified and obtained with much intensity. Surface-enhanced Raman spectroscopy (SERS) significantly enhances the capabilities of conventional Raman spectroscopy (RS) for analyzing pharmaceutical and food samples through plasmonic signal amplification using nanoparticles. Silver nanoparticles (Ag-NPs) are particularly advantageous as SERS substrates compared to gold nanoparticles (Au-NPs), offering greater signal enhancement. Furthermore, Ag-NP synthesis via the chemical reduction method is more cost-effective and less labor-intensive than Au-NP synthesis. In this study, Ag-NPs were synthesized by reducing silver nitrate (AgNO₃) with trisodium citrate (Na₃C₆H₅O₇), which acts as both a reducing and capping agent. Characterization revealed an optimal Ag-NP size range of 25–45 nm. This optimized substrate yielded significantly enhanced SERS signals, resulting in clearer and more intense spectral peaks.