Optical and dielectric properties of polymer nanocomposite based on PEG/NaAlg blend and Ag/Au nanoparticles prepared by green synthesis method for energy storage applications

Green synthesized silver/gold nanoparticles (Ag/Au NPs) with an average size of 19 nm have been added to polyethylene glycol/sodium alginate (PEG/NaAlg) by the casting technique. The PEG/NaAlg blend's semicrystalline structure was revealed by the XRD, which also showed peaks that indicated the existence of silver and gold nanoparticles. Diffraction peak intensities change when Ag/Au NPs are added to the blend, indicating that some PEG/NaAlg composite domains are broken by the blend-Ag/Au NP interactions. A change in peak position and intensity is observed in the FT-IR absorption spectrum after adding Ag/Au nanoparticles. The optical characteristics were studied by analyzing the UV-Vis absorbance spectrum. Incorporating Ag/Au NPs reduced band-gap values, confirming that Ag/Au NPs can be used in many applications as band-gap-regulated optical materials. The Optical band gap values decrease in the presence of Ag/Au NPs due to the correlation between defect levels and localized state density. All of the samples follow Jonscher's power law in their AC conductivity spectra. Maximum values of epsilon '' at lower frequencies were associated with an increase in energy loss in the fabricated composites, while maximum values of epsilon ' at lower frequencies were associated with the influence of the interfacial polarization generated by charge accumulation. A semicircle arc can be seen on the Cole-Cole plot because of the relaxation process and grain boundary. The prepared films become polarized and have a greater capacity to store electrical energy when exposed to an electric field. These composite materials can be utilized in flexible capacitors.