Optical Properties of SiO2 Nanoparticles Doped PEO-LiClO4 Nanocomposite Polymer Electrolyte Films

Abstract

The optical transmission and absorption spectra were recorded in the wavelength range 200-800 nm for optimized high conducting concentrations of SiO2 nanoparticles in PEO-LiClO4 -m wt% SiO2 polymer matrix. Values of absorption coefficient, direct band gap energy, measure of extent of band trailing or Urbach energy, absorption edge and constant, B, have been investigated by optical characterization method. Effect of concentration of SiO2 nanoparticles in the polymer matrix on these parameters has been discussed. It has been observed that addition of SiO2 nanoparticles increases structural disorder and fluctuations of the internal fields associated with it. Small change in the concentration of SiO2 nanoparticles changes optical properties of nanocomposite polymer matrix. It was also found that direct band gap fits in the lower energy region of fundamental absorption edge