Hybrid polymer nanocomposites with tailored band gaps and UV absorption for advanced applications in optoelectronics and UV protection

Herein we report the method to tailor the band gap and UV absorption of polyvinyl alcohol (PVA)/graphene oxide (GO)-silver (Ag)/glutaraldehyde (GA) hybrid polymer nanocomposites. The modifications brought by neutron irradiation to the optical and dielectric characteristics enabled the band gap and UV absorption-tailored polymer nanocomposites to be obtained. Neutron-irradiated samples, compared with their unirradiated counterparts, exhibit a reduction in transmittance to 78%, rendering them opaque to UV–visible light after irradiation. The energy band gap decreases from 5.25 to 4.09 eV upon irradiation. Furthermore, upon neutron-irradiation the relaxation time increases from 7.63 × 10⁻⁴ to 0.02 s which is evident by the shift in electric modulus imaginary part (M") peak to a lower frequency region, indicating an increase in relaxation time. The Cole–Cole plot for irradiated samples demonstrates lower fitting parameter (α) values of the modified Havriliak–Negami function, indicating a departure from pure capacitor-like behavior. The neutron irradiation leads to a decrease in conductivity from 44.6 × 10⁻⁷ to 0.09 × 10⁻⁷ S/cm.