Casting method study of Poly vinyl alcohol sodium iodide nanocomposite films.

In the present work, nanocomposites of polyvinyl alcohol (PVA) and sodium iodide (NaI) nanoparticles have been prepared by casting technique. PVA has been doped by different percentage of sodium Iodide (0, 1, 2, 3 and 4 wt. %). The structural, electrical and optical properties of polymer electrolytes have been investigated. The experimental results showed that the D.C electrical conductivity increases with increase the sodium iodide nanoparticles concentrations. The activation energy of D.C electrical conductivity decreases with increase of sodium iodide nanoparticle concentrations. At low frequency, the variation of dielectric constant and dielectric loss with frequency shows the presence of material electrode inter-face polarization processes. The exponent factor found is between 0.98 and 0.086 and obeys the universal power law. The optical properties of samples are investigated in the wavelength range from 200 nm to 1100 nm at 300 K using UV-Vis spectroscopy. The absorbance, extinction coefficient, refractive index and reflectance of PVA doped with NaI increase with increasing of doping percentages except the transmittance. The real and imaginary parts of dielectric constants and optical conductivity are increasing with increase sodium iodine concentration. From direct allowed transition the optical energy gap decreases from 4.27 eV (for pure PVA) to 4.22 eV (for PVA+40%NaI). [ABSTRACT FROM AUTHOR]