Solid polymer electrolyte films based on polymer blends of polyvinyl pyrrolidone (PVP) and poly methyl methacrylate (PMMA), with different concentration of KBr were prepared using casting technique. Optical studies were performed using Ultraviolet-visible (UV-Vis) spectroscopy. The optical properties of these films were varied by varying KBr concentration. The results show the absorption edge for electrolyte samples shifts toward a lower energy region by increasing the salt concentration, leading to the band gap reduction. The band gap energy data showed that the incorporation of KBr into the polymeric system causes charge transfer complexes in the blend polymer, which lead to increase in the electrical conductivity, by providing additional charges in the lattice.
