Tailored localized surface plasmon resonance behavior of Synthesised Silver Nanoparticles via Modified Lee–Meisel Method

This study reports the synthesis and comprehensive characterization of silver nanoparticles (AgNPs)with tunable optical properties, focusing on their localized surface plasmon resonance (LSPR) behavior andrelevance to nanoscale light–matter interactions. AgNPs were synthesized via a modified Lee-Meisel methodemploying trisodium citrate as both a reducing and capping agent. Systematic variation in citrate volumeenabled controlled modulation of nanoparticle size within the 10–40 nm range, as confirmed by TransmissionElectron Microscopy (TEM). UV–Visible spectroscopy revealed distinct LSPR absorption peaks in the visibleregion. Photoluminescence (PL) analysis demonstrated enhanced emission for smaller nanoparticles, attributedto increased plasmon–exciton coupling and reduced non-radiative damping. Scanning Electron Microscopy(SEM) and Energy Dispersive X-ray Spectroscopy (EDX) validated surface morphology and elemental purity,respectively. Fourier Transform Infrared Spectroscopy (FTIR) identified functional groups such as hydroxyl andcarboxylates, derived from citrate, which contributed to surface passivation and colloidal stabilization. X-rayDiffraction (XRD) confirmed the face-centered cubic (FCC) crystal structure of metallic silver with highcrystallinity and phase purity. The combined results underscore the critical role of synthetic parameters intailoring nanoparticle size, surface chemistry, and plasmonic response. This work establishes AgNPs as highlytunable platforms for integration into plasmon-enhanced technologies, with promising applications inbiosensing, photothermal therapy, and nanophotonic systems.