Effects of Tb(NO₃)₃ salt on the structural characteristics, optical, and radiation shielding properties of (PVA-PVP- PEG) polymeric composite films

Herein, this study introduces a simple, effective, and potentially successful approach to the preparation of polymeric composite systems using a Polyvinyl alcohol (PVA)-Polyvinyl pyrrolidone (PVP)-Polyethylene glycol (PEG) (PVA-PVP-PEG), (8:1:1) as the host polymeric blend with the inclusion of Tb(NO₃)₃-salt filler. The diffraction of X-rays (XRD), infrared spectroscopic (FTIR), Ultraviolet–visible (UV–vis) spectroscopy, and Phy-X/PSD software were utilized to analyze the modified samples’ structures, identify their optical and radiation shielding properties. The XRD patterns show the presence of Tb(NO₃)₃ phases inside the composite matrix, where adding filler causes modifications in the polymeric network’s structure for filled composite samples. FTIR analysis showed that the Tb(NO₃)₃-salt interacted with the blend’s functional groups via H-bond formation. The UV–Vis spectra analysis showed all samples, especially those loaded with 8.0 wt.% Tb(NO₃)₃-salt has the highest values for absorbance, dielectric constant, refractive index, extinction coefficient, and optical and electrical conductivity. Tauc’s formula, the ASF model, and " \({\varepsilon }_{i}-hv\) plots were all applied to investigate optically the band gap in great detail. The values of \({\text{E}}_{\text{d}}\) and \({\text{E}}_{\text{o}}\) and \({\text{n}}_{\text{o}}\) have been investigated using a single oscillator model where their values were controlled by Tb(NO₃)₃- salt content. Using calculated gap energy, various approaches were applied to obtain the conceptual significance of the linear refractive index \((n)\). The nonlinear optical parameters \({\upchi }^{(1)}\), \({\upchi }^{(3)}\), and \({\text{n}}_{2}\) increased noticeably as the Tb(NO₃)₃-salt percentage is increased to 8.0 wt%. The suggested largely doped Tb(NO₃)₃-salt composites show great promise as a CUT-OFF laser filters and attenuators in addition to being used in laser power-limiting technology. Based on our results, the sample was 8.0 wt.% Tb(NO₃)₃-salt has better gamma-ray shielding properties than the others because it has the largest Tb(NO3)3-salt concentration. The study opens a new route to fabricate Tb(NO₃)₃/(PVA-PVP-PEG) polymeric composites with superior optical properties.