MgO metal oxides improve the structural, dielectric, and linear/nonlinear optical properties of PVA/PVP/PEG blends for laser-limiter and optoelectronic applications
T.H. AlAbdulaal, Wan Rafizah Wan Abdullah
Abstract
Producing novel nanocomposite polymeric materials with enhanced structural and optical properties is crucial for various applications, particularly in optics. In this study, a solution casting method was employed to synthesize a blend of polyvinyl alcohol (PVA), polyvinyl pyrrolidone (PVP), and polyethylene glycol (PEG) polymers, serving as host matrices for magnesium oxide nanoparticles (MgO NPs) at different weight percentages (0.05, 0.27, 0.55, 2.7, 5.5, and 11.04 wt%). The crystallinity behavior of the resulting thin films was analyzed using X-ray diffraction (XRD), while scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM/EDX) investigated the morphology and grain size of the MgO NPs. Fourier-transform infrared spectroscopy (FT-IR) identified the chemical groups present in the MgO: PVA/PVP/PEG nanocomposites. Ultraviolet–visible-near-infrared (UV–Vis-NIR) spectrophotometry was applied to study the optical properties and examine the effect of varying MgO NP concentrations. The pristine PVA/PVP/PEG polymer exhibited 92 % transparency in the visible range, which decreased to 0 % with increasing MgO content. The host polymeric sheet displayed both direct and indirect bandgaps of 5.47 eV and 4.82 eV, respectively, which reduced to 5.13 eV and 3.88 eV as the MgO NP percentage increased. Seven theoretical models based on the energy bandgaps (Eg) were used to calculate the linear refractive index and nonlinear optical properties of the MgO: PVA/PVP/PEG thin films. The high-frequency dielectric constant increased, while the static dielectric constant decreased upon the addition of MgO NPs. Furthermore, the MgO: PVA/PVP/PEG nanocomposites attenuated laser intensity at wavelengths of 635, 532, and 450 nm, as well as the power intensity of a visible lamp at 1050 W/m 2 . The results demonstrate that these MgO: PVA/PVP/PEG polymeric nanocomposite sheets are promising candidates for applications in laser-based medical devices, optoelectronics, and optical filters.