Characterization of polyvinyl alcohol film doped with sodium molybdate as solid polymer electrolytes

Abstract

In this paper, optical and electrical properties of solid films of polyvinyl alcohol (PVA) complexed with different concentration of sodium molybdate (Na2MoO4) have been analyzed. The shift and decrease in intensity of FTIR spectra of PVA doped with 9 wt.% of Na2MoO4 indicates the formation of charge-transfer complex between the cations of the sodium salt and the hydroxyl groups of PVA. The XRD results showed that the amorphous domains of PVA polymer matrix increased upon addition of Na2MoO4 salt. An increase of absorption and refractive index for solid electrolyte films has been observed. The decrease in optical band gap from 6.35 eV for pure PVA to 4.37 eV for PVA doped with 9 wt.% Na2MoO4 was observed. The results of electrical measurement showed that the conductivity increases as Na2MoO4 content increases. The DC conductivity of about 1.09 × 10− 6 S/cm was achieved for PVA incorporated with 9 wt.% Na2MoO4 salt. The AC conductivity spectra exhibit a dispersion manner at high frequencies. The behavior of the frequency exponent (s) with temperature was used to interpret the mechanism of ion transport. The variation of DC conductivity with temperature follows Arrhenius equation. The dielectric constant increased with increasing temperature and decreased with increasing frequency.