Green Synthesis of Silver Nanoparticles Using Plant Extracts: Recent Advances in Mechanisms, Parameters, and Characterization Methods

Abstract: The green synthesis of silver nanoparticles (AgNPs) using aqueous plant extracts has emerged as a sustainable, cost-effective, and biocompatible alternative to conventional chemical methods. This review systematically examines recent advancements (2020–2025) in plant-mediated AgNP synthesis, focusing on synthesis mechanisms, critical process pa-rameters, and comprehensive physicochemical characterization. Phytochemicals such as fla-vonoids, polyphenols, and alkaloids act as natural reducing and stabilizing agents, facilitating the bioreduction of Ag⁺ ions under eco-friendly redox conditions. Key synthesis parameters, including pH, temperature, extract concentration, and silver nitrate concentration, signifi-cantly influence nanoparticle size, morphology, crystallinity, and colloidal stability. A suite of characterization techniques, including UV-Visible spectroscopy, Fourier Transform Infra-red Spectroscopy (FTIR), X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Dynamic Light Scattering (DLS), and Zeta Po-tential analysis, is used to assess particle structure, surface chemistry, and dispersion quality. The review highlights the critical role of synthesis conditions in tailoring nanoparticle attrib-utes and discusses methodological variations across studies. Standardization of protocols and integration of advanced analytical tools are recommended to improve reproducibility and en-able scalable green synthesis for biomedical, environmental, and industrial applications.