Effect of gold and silver mixed nanofillers and gamma irradiation on the structure and physical properties of PVA/PVP nanocomposite

Gold and silver nanoparticles (AuNPs and AgNPs) were synthesized using the leaf extract of Chenopodium murale (C. murale) via a green, eco-friendly synthesis approach. The nanoparticles were incorporated into a polyvinyl alcohol/polyvinyl pyrrolidone (PVA/PVP) matrix through the casting method to produce composite thin films. These films were subjected to gamma irradiation at doses of 3, 5, and 8 Mrad, and their structural and optical properties were systematically analyzed before and after gamma irradiation. FT-IR spectroscopy indicated significant structural rearrangements within the polymeric matrix, attributed to gamma irradiation effects. Ultraviolet–visible (UV–Vis) spectroscopy confirmed the presence of a strong charge transfer band in the UV region and characteristic surface plasmon resonance (SPR) peaks of AgNPs and AuNPs, observed in the 420–540 nm range. Detailed optical analysis enabled the determination of indirect and direct energy band gaps, revealing irradiation-induced modifications. Gamma irradiation influenced the size and distribution of nanoparticles, resulting in notable alterations in the structural and optical properties of the nanocomposite films. These findings underscore the potential of gamma-irradiated AuNP/AgNP composites in modern applications like optoelectronics and materials science, where tailored structural and optical properties are critical.