Investigation of the doping mechanism and electron transition bands of PEO/KMnO4 complex composite films

Abstract

Polyethylene oxide (PEO) incorporated with potassium permanganate (KMnO4) was prepared using the solution casting technique forming PEO/KMnO4 complex composite films. The physicochemical properties, doping mechanism, and electron transition bands of PEO/KMnO4 were investigated. Introducing KMnO4 PEO matrix led to a decrease in crystallinity degree and optical bandgap energy due to the creation of polarons and bipolarons that form new energy levels in the bandgap between the HOMO and LUMO; in addition, to form of a new transition band appears at about 380 nm is attributed to the n{-}{pi }^{*} electronic transitions are generated due to the unsaturated center of the molecules. The existence of KMnO4 in the polymer matrix leads to the blocking of light in the 250–400 nm range. Consequently, PEO/KMnO4 complex composite films could be used as UV-light shielding filters. Furthermore, the electrical conductivity of the PEO/KMnO4 complex composite films increases as KMnO4 concentration is increased in the PEO matrix since the created new energy levels in the bandgap between the HOMO and LUMO can be populated with conduction electrons providing true ohmic conduction with the delocalization of the electron densities moving on the polymer chain.