Silver nanoparticle kinetics: plasmonic and quantum confinement modeling
摘要
The synthesis and optical properties of silver nanoparticles (AgNPs) derived from water hyacinth were simulated using a computational framework integrating reduction kinetics, particle size distribution modeling, and quantum confinement theory. The reduction of silver ions to metallic silver followed pseudo-first-order kinetics, with Ag0 concentration increasing from 0 to approximately 997 µM over 120 min. Nanoparticles exhibited a lognormal size distribution with mean diameters ranging from 40 to 100 nm, a number-weighted mean of 90.3 nm, an intensity-weighted Z-average of 91.7 nm, and a dispersity index of 0.08, indicating uniform growth. Simulated UV-Vis spectra showed a size-dependent surface plasmon resonance (SPR) peak shifting from 392 nm for 10 nm particles to 421 nm for 50 nm particles, with absorbance increasing from 0.21 to 2.25 A.U. over 150 min. Bandgap energies decreased from 3.12 eV for smaller nanoparticles (~ 15 nm) to 3.07 eV for larger particles (~ 21 nm), reflecting reduced quantum confinement effects. Temperature-dependent simulations demonstrated that higher temperatures (25–125 °C) accelerated Ag+ reduction and particle growth, producing nanoparticles between 10 and 50 nm, with rapid nucleation at 125 °C causing slight broadening of the size distribution. Collectively, these results highlight the strong correlation between nanoparticle growth kinetics and optical properties, showing that computational modeling can effectively predict and optimize synthesis conditions to achieve desired plasmonic and electronic characteristics for applications in catalysis, sensing, and photonics.