Synthesis, structural, optical, and dielectric properties of CuWO4/PVP/Cs bio-nanocomposites for some industrial applications

Abstract

The nanocomposites of biopolymers and bimetallic oxides are exciting classes of materials. Besides the economic and environmental considerations, these materials became the best candidates for various applications in industry and medicine. In this study, CuWO4 nanoparticles (NP) with high purity were prepared by co-precipitation and loaded into poly(vinyl pyrrolidone)/chitosan (PVP/Cs) films. XRD results showed that CuWO4 has a triclinic phase with an average crystallite size of 43 nm. PVP/Cs is semi-crystalline blend and its crystallinity degraded by CuWO4 incorporation. EDX analysis was used to study the chemical composition of all samples. FE-SEM showed that CuWO4 has particle sizes of 50–150 nm and that the crack-free surface of PVP/Cs became rougher and more porous after loading of CuWO4 NP. FTIR confirmed the presence of the reactive functional group of CuWO4, PVP, and Cs and that the low doping ratio of CuWO4 NP restricted the functional group’s vibrations. The UV–vis–NIR investigation showed that the films have a small absorption index and high transmittance in the range of 68–90%. The direct and indirect band gaps ({E}_{g}^{dir} and {E}_{g}^{ind}) of the blend were found equal to 5.0 and 4.2 eV and can be tuned by CuWO4 content. Similarly, the index of refraction and carrier concentration/electron effective mass ratio (N/m*), the dielectric constant (ε′ = 8.3–24.5), and the dielectric loss depend on the applied frequency, temperature, and CuWO4 filler content. The conductivity (σac) ranges from 1.2 × 10–6 to 9.16 × 10–4 S/m and exhibits the Arrhenius behavior. The optical and dielectric results show that the prepared PNC may suit some energy storage device,s such as supercapacitors, and organic optoelectronic devices, such as light emitting diodes and/or photovoltaic solar cells.