Synthesis, structure, and optical properties of Fe₂O₃:PVA/PVP/PEG polymeric nanocomposite sheets for low-cost optical limiters under laser and solar visible lights

The current study suggests using the PVA/PVP/PEG polymeric blend as a pure medium and iron oxide (Fe₂O₃) nanoparticles as a filler. A simple, effective, and inexpensive chemical growth, sol–gel auto-combustion approach was utilized to produce Fe₂O₃ nanoparticles. Then, the inexpensive and environmentally friendly solution casting method was employed to synthesize various concentrations of Fe₂O₃:PVA/PVP/PEG nanocomposites. The XRD technique has proven the semi-crystalline structural behavior of the investigated Fe₂O₃:(PVA/PVP/PEG) composite sheets. The SEM/EDX images were used to analyze the surface morphology of the Fe₂O₃ NPs and all prepared polymeric sheets, as well as to calculate the average grain size, which was 110.5 nm for the Fe₂O₃ NPs. The FT-IR technique with a range of 4000 to 400 cm⁻¹ was also used to analyze the chemical and structural properties of the polymeric nanocomposite sheets. UV–Vis–NIR spectroscopy was functioning to optically measure the linear/nonlinear properties of the proposed composite sheets over a wavelength range (190—2500 nm). In this research work, the direct and indirect optical bandgaps of the PVA/PVP/PEG polymer were found to be 5.40 and 4.92 eV, respectively. These energy bandgaps decreased to 4.69 and 2.15 eV as the Fe₂O₃ weight increased in the host matrix. A Z-scan system with three excitation sources—a He–Ne laser at 632.8 nm, a green diode laser at 532 nm, and a blue laser at 450 nm—was also operated to optically study the limiting effects of the prepared polymeric sheets. The power of lasers and visible light was significantly reduced by incorporating a high concentration of Fe₂O₃ doping into the polymeric sheets. To conclude, the synthesized Fe₂O₃-doped PVA/PVP/PEG nanocomposites worked well and showed great promise in optical, optoelectronic, and laser filter devices.