Evolution of the optical properties of PVA films filled with Sodium Iodide


Transparent films of polyvinyl alcohol with different doping Sodium Iodide concentrations were prepared by using solution cast technique. The optical absorption measurements were carried out for all samples at room temperature across the wavelength regions. The study has been also extended to include the changes in the optical parameters including the band tail width and band gap energies for the samples; It was found that the optical absorption is due to direct and indirect transitions, and the optical energy gaps values shifted to lower energies on sodium iodide concentration for all transitions. Also absorption spectrums after annealing for three hours at temperature are investigated. Moreover, the study of complex refractive index showed dependence on dopant concentrations.