Structural, optical, electrical and dielectric properties of PVA-YCl <inf>3</inf> films

Abstract

Polyvinyl alcohol (PVA) films doped with 10wt.% of yttrium chloride (YCl3) have been made by casting from their aqueous solutions. The structure of un-annealed and annealed PVA-YCl 3 films was studied using X-ray diffraction (XRD) patterns and Fourier-transform infrared spectroscopy (FTIR). Both FTIR and XRD revealed that the crystalline ratio of the studied samples increased due to the effect of annealing. The effect of annealing on the optical properties has been studied. Dispersion of the refractive index was described using the single oscillator model. The single oscillator energy and the dispersion energy were estimated. The calculated optical band gap of all PVA-YCl 3 films was 5.0eV. The behavior of ac conductivity showed that the conduction mechanism of PVA-YCl 3 films was correlated barrier hopping model. The dielectric constant and dielectric loss index were decreased with the increase of the field frequency. The electric modulus granted a straightforward technique for assessing the dielectric relaxation time. The calculated activation energy obtained from the electric modulus mechanism was 0.172eV.