Effect of Precursor Concentration on the Morphology, Optical Properties, and Biological Activity of Silver Nanomaterials Synthesized by Atmospheric Pressure Microplasma

Abstract

Silver nanomaterials are widely utilized in drug delivery and cancer treatment due to their exceptional optical and antimicrobial features that can improve the efficacy of therapy. In this work, silver nanomaterials are synthesized with atmospheric-pressure microplasma at different precursor concentrations (6, 9, 12, and 15 mM) using silver nitrate as a silver source; additionally, sucrose (2 mM) is used as a stabilizing agent. From the x-ray diffraction (XRD), it is clear that all the synthesized samples exhibit peaks due to silver, without impurity peaks, indicating pure nanomaterial synthesis. The crystallite size reduces from 32.76 to 30.55 nm with increasing precursor concentration. The scanning electron microscopy (SEM) result suggests that the morphology transforms from nanosheets to nanoparticles as a function of precursor concentration. With increasing precursor concentration, the bandgap increases (3.38, 3.43, 3.5, and 3.57 eV). Fourier transform infrared (FTIR) spectroscopy showed bands at 500‐600 cm⁻¹ associated with silver nanomaterial formation. The nanomaterials exhibit effective antimicrobial activity, particularly at 6 and 15 mM precursor concentrations. This study demonstrates that precursor concentration is an important and tunable parameter controlling morphology and enhancing physicochemical and biological properties, supporting potential biomedical and antimicrobial applications.