Structural, physical and optical properties of Bi_4.86La_1.14O₉/PVA thin-film for shielding applications

An innovative lead-free, Bi_4.86La_1.14O₉/polyvinyl alcohol (PVA) nanocomposite (LB-PVA), thin-film was fabricated. The Bi_4.86La_1.14O₉ nanofiller, synthesized via sol–gel method, was blended with PVA and crosslinked with citric acid using a coating technique. The nanofiller was characterized by XRD, TEM, zeta potential, and DLS, while the nanocomposite thin-film was analyzed via FTIR, XRD, SEM-EDX, and UV–vis spectroscopy, with comparisons to raw crosslinked PVA. The key physical properties were analyzed: density, OPD, Vm, V_∘, N, Rp and Ri. The increased V_∘ value opposed the density direction, leading to reduced OD in the LB-PVA thin-film. In addition to mechanical properties (e.g., TS), the optical characteristics including absorbance spectra other properties were systematically investigated. The γ-ray shielding performance (0.015–1.50 MeV) was rigorously evaluated through combined Py-MLBUF and Phy-X/PSD computational quantitative analysis, using LAC, MAC, HVT, and TVT as primary metrics. Their quantified dual computational methods showed excellent agreement with minimal deviation (< 0.03%). The buildup factors EBF and EABF for single and double layers, along with MFP, Zeff, σ-electron, and σ-atomic were also investigated via Py-MLBUF simulation. The novel LB-PVA composite, with ultralow doping (∼0.95%), exhibited superior MAC compared to CPVA, attributed to high-Z synergy (La/Bi) and optimal nanoparticle dispersion.