Impact of gamma irradiation on the structural, linear and nonlinear optical properties of lead oxide incorporated PVA/graphene blend for shielding applications

Abstract

In this study, the structural, linear and nonlinear optical performance of PVA/graphene polymeric composites (PVA/Gr PCs) incorporated with lead oxide (Pb3O4) have been modified by exposing with gamma irradiation (γ-irradiation). Pb3O4 incorporated PVA/Gr PCs were prepared by the solution casting procedure and exposed to different γ-irradiation doses (50, 100, 150, 200 and 250 kGy). The structural and optical properties of the irradiated PCs were examined by FT-IR, XRD and UV–visible spectrophotometer. The XRD analysis reveals that the semi crystallinity feature of the PCs decreases with increasing the irradiation dose. The UV–Vis.-NIR measurements show that the optical absorbance of the PCs increases upon increasing the irradiation dose to 250 kGy. The direct optical bandgap energy shrinks from 5.26 eV (non-irradiated PC) to 4.82 eV (250 kGy irradiated PC). Obvious enhancement in the optical parameters (refractive index, dielectric (real εr, imaginary εi) constant and optical conductivity is achieved. Furthermore, the first-order linear susceptibility (χ(1)), third-order nonlinear susceptibility (χ(3)) and nonlinear refractive index (n2) of Pb3O4 PCs are also tailored via controlling the γ-irradiation dose. This enhancement in the linear and nonlinear optical parameters of PCs was pronounced in the UV region. For instance, at 285 nm, χ(1) increases from 0.19 to 0.45 and χ(3) increases from 2.25 × 10−13 to 6.76 × 10−12 esu as the γ-irradiation dose is increased from 0 to 250 kGy. These findings nominate the potential applications of Pb3O4 PCs in dosimetry and shielding devices.