Structural, optical, and morphological evaluation of PVA/Bi-Ni oxide-rGO nanocomposite casted films for optical devices applications

Abstract

Abstract Herein, the polyvinyl alcohol (PVA) films doped with various concentrations of Bi 2 O 3 -NiO-rGO (BNG) nanoparticles were prepared through casting method. BNG nanoparticles were synthesized first using the co-precipitation method and then loaded into the polymer matrix. Various techniques like X-ray diffraction, Raman spectroscopy, and optical microscopes were used to determine the PVA’s structure after BNG nanoparticle additives. The thermal stability of the PVA’s film after the additive BNG nanoparticles was examined using the DSC technique. Furthermore, the optical parameters including bandgap energy (E g ), Urbach energy (E U ), refractive index (n), optical conductivity, and optical dielectric constants were investigated via the absorbance and transmission data recorded using UV-visible spectroscopy. In addition, the photoemission spectra of the PVA matrix were determined after the inclusion of BNG nanoparticles. The E g value decreases from 5.57 eV to 3.94 eV and from 4.8 eV to about 1.98 eV for direct and indirect transitions, respectively. While the E U value increases from 0.39 eV for pure PVA to about 3.23 eV for PVA: 4%BNG. The refractive index grows with the insertion of BNG to the PVA from 1.387 for pure PVA to about 5.157 for PVA: 4%BNG, which is a good suggestion for optical glasses applications. In addition, the increase in optical dielectric constants and optical conductivity with rising the BNG nanoparticle concentrations in the PVA matrix was confirmed. Such enhancement suggests the use of prepared samples in optical device applications.