Effect of BaWO 4 nanoparticles on the structural and optical characteristics of the PS/BaWO 4 nanocomposites for optical applications

Abstract

This work explores the effect of BaWO₄ nanoparticles (NPs) with varying concentrations (0, 1, 2, and 3 wt%) on the structural, surface/volume energy loss functions, and linear/non-linear optical properties of polystyrene/BaWO₄ nanocomposites. The XRD pattern indicates the formation of pure BaWO₄ NPs with a tetragonal structure. SEM image revealed the uniform scroll-like shape of the synthesized BaWO₄. The direct bandgap energy reduced from 3.88 eV in the PS film to 3.85 eV, 3.73 eV, and 3.71 eV with increasing BaWO₄ loading. Meanwhile, the Urbach energy for PS film was 1.25 eV, which rose to 1.38, 1.43, and 1.54 eV with enhanced BaWO₄ contents. In addition, the refractive index of the PS film boosted after the incorporation of BaWO₄ with a ratio of 1% and 2%wt. However, it dropped after the addition of 3% of the BaWO₄. The optical conductivity and electrical conductivity of pristine PS improves after incorporating BaWO₄ into the PS matrix, attributable to an increase in charge transfer and a corresponding rise in the absorption coefficient. Moreover, optical parameter such as, the oscillator energy (E₀) and the dispersion energy (E_d), relaxation time (τ), N/m* were concluded. The oscillation frequency (ω_P) value was also found to be 0.13× 10¹³ sec⁻¹ for PS polymer, which increased to 0.23× 10¹³ sec⁻¹ and 0.34 × 10¹³ sec⁻¹ for PS/1%BaWO₄ and PS/2%BaWO₄ films, respectively, and then declined to 0.08× 10¹³ sec⁻¹ for PS/3%BaWO₄ film. The non-linear refractive index (n ₂ ), linear optical susceptibility (χ⁽¹⁾), and third-order non-linear optical susceptibility (χ⁽³⁾) for the pristine PS and all PS/BaWO₄ nanocomposite films were derived. These results confirm that the PS/1% BaWO₄ and PS/2% BaWO₄ samples are suitable for utilization in photonic devices, anti-reflective coatings, and waveguide technology, while, the PS/3% BaWO₄ sample is employed in applications that depend on the rapid transmission of optical signals, such as optical communications.