Tuning the optical properties, AC conductivity and dielectric modulus of PVA membrane by inclusion of TiO2 nanoparticles

The article demonstrates the feasibility of tuning the optical and electrical properties of polyvinyl alcohol (PVA) by adding different wt% of TiO 2 nanoparticles (0.001–0.01 wt%). UV–visible, photoluminescence and LCR spectroscopies techniques were used. UV–visible measurements of PVA/TiO 2 membranes displayed a shift in the absorbance edge across the region of longer wavelength. This reflects a decrease in the bandgap energy, which indicates an increase in the electrical AC conductivity of the samples. Furthermore, the transmittance of a pure PVA membrane decreases from 85% for pure PVA to 3% for PVA/TiO 2 with 0.01 wt%. In addition, an amendment was observed in the optical parameters of nanocomposite membranes. The photoluminescence emission spectra exhibited a luminescence response of the PVA/TiO 2 samples and significant emission bands were generated with the increase in the TiO 2 nanoparticles. With increasing TiO 2 nanoparticles, an increase in the AC conductivity and an improvement in the dielectric parameters of the samples were observed. The electric modulus was calculated and used to evaluate the relaxation behaviour in the nanocomposite membranes.