Structural, Electrical and Optical Characterization of Pure and Doped Poly (Vinyl Alcohol) (PVA) Polymer Electrolyte Films

Abstract

A sodium ion conducting polymer electrolyte based on Poly (Vinyl Alcohol) (PVA) complexed with Sodium Iodide (NaI) was prepared using solution cast technique. The structural properties of composite PVA polymer electrolyte films were examined by XRD. The XRD results revealed that the amorphous domains of PVA polymer matrix increased in size with the increase of NaI salt concentration. The variation in film morphology was examined by scanning electron microscopy. FT-IR spectra studies for pure PVA and complexed films revealed the vibrational changes that occurred due to the effect of dopant salt in the polymer. DC conductivity was measured in the temperature range of 303–373° K and the conductivity was found to increase with the increase of dopant concentration as well as temperature. Optical absorption studies were made in the wavelength range 200–600 nm. The absorption edge, direct band gap, and indirect band gap values were evaluated.

Keywords:

• FTIR
• ionic conductivity
• optical band gaps
• polymer electrolyte XRD
• SEM