Tunable optoelectronic properties of PVC–Bi2O3 nanocomposites

Abstract PVC/(Bi 2 O 3 ) x (x = 0, 2.5, 5, 10, 15, and 25 wt %) nanocomposites were produced using the solution casting technique and thoroughly examined. The produced nanocomposites were examined using several characterization techniques, including X-ray diffractometry (XRD), scanning electron microscopy(SEM), differential thermogravimetric analysis (DTG), and UV-Vis-NIR spectroscopy. X-ray diffraction (XRD) analysis confirmed the semi-crystalline nature of PVC and unveiled structural changes dependent on the concentration of Bi 2 O 3 incorporated into the matrix. The Debye-Scherrer equation was used to determine the size of the Bi 2 O 3 nanoparticles, and it was discovered that aggregation caused the size of the particles to rise following dispersion in the polymer matrix. Scanning electron microscope (SEM) images illustrated a shift from a smooth surface to a porous, honeycomb-like structure with effective nanoparticle distribution. Thermal investigations showed that the introduction of Bi 2 O 3 modifies the degradation characteristics of PVC. Optical analysis revealed increased absorbance, decreased transmittance, and a notable redshift in the absorption edge as Bi 2 O 3 content increased. Both direct and indirect optical band gaps showed significant reductions, alongside a rise in Urbach energy, suggesting the emergence of localized tail states. The refractive index showed a significant increase, reaching approximately 4.5 for PVC/25 wt% Bi 2 O 3 , while there were notable improvements in the extinction coefficient, optical conductivity, dielectric constants, and free carrier density. The dispersion analysis conducted with the Wemple–DiDomenico model indicated enhanced oscillator and dispersion energies, and the nonlinear optical susceptibility, along with the nonlinear refractive index, exhibited a marked increase with the addition of Bi 2 O 3 . These findings emphasize the strong interactions involved in interfacial charge transfer and illustrate the potential of PVC/Bi 2 O 3 nanocomposites for applications in optoelectronics, energy storage devices, optical sensors, and nonlinear optical applications.