Optical and Structural Properties of Biosynthesized Silver Nanoparticle Encapsulated PVA (Ag–PVA) Films

Abstract

Silver (Ag) nanoparticles were successfully synthesized under ambient temperature employing Leucas Aspera (LA) leaves. The synthesis of silver nanoparticles at first confirmed by noting variations in the colour and subsequently morphological characteristics of prepared LA–Ag nanoparticles have been explored by using HR-TEM, and the particle size was found to be 3.67 nm which is in good agreement with XRD. SAED pattern represent the polycrystalline nature of Ag and crystallographic planes are close agreement with XRD. Implementing Diffraction Light Scattering (DLS) the average size is estimated to be 7 nm and the polydispersity index (PDI) was noticed to be 0.209 evince the uniform distribution. The same synthesised nanoparticles (NPs) were encapsulated further within a matrix of polyvinyl alcohol (PVA). Moreover, prepared nanocomposite films were characterised and correlated with both PVA-Ag matrix and pure PVA. To examine the optical characteristics of both LA–Ag-NPs and pristine PVA films were characterised via UV–Visible spectra. The influence of doping PVA with LA–Ag-NPs was being explored, i.e., structural, and morphological improvements including optical band gap, absorption coefficient, refractive index as well as optical conductivity. Besides, Fourier Infrared Spectroscopy benefitted to classify the alterations in the functional group. Scanning electron microscope visuals of synthesized nanoparticles reveal spherical shape in a polymer matrix, although the outcomes of energy dispersion findings support the appearance of silver. The structural parameters were determined by the use of X-ray diffraction studies, reflecting the d-spacing values and the crystalline nature with doping silver nanoparticle in PVA. This article addresses the research on structural and optical properties of LA–Ag–PVA nanocomposite films.