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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 $$n{-}{\pi }^{*}$$ n - π ∗ 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.

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We report the synthesis of hybrid thin films based on polymethyl methacrylate) (PMMA) and polystyrene (PS) doped with 1%, 3%, 5%, and 7% of cerium dioxide nanoparticles (CeO2 NPs). The As-prepared thin films of (PMMA-PS) incorporated with CeO2 NPs are deposited on a glass substrate. The transmittance T% (λ) and reflectance R% (λ) of PMMA-PS/CeO2 NPs thin films are measured at room temperature in the spectral range (250–700) nm. High transmittance of 87% is observed in the low-energy regions. However, transmittance decreases sharply to a vanishing value in the high-energy region. In addition, as the CeO2 NPs concentration is increased, a red shift of the absorption edge is clearly observed suggesting a considerable decrease in the band gap energy of PMMA-PS/CeO2 NPs thin film. The optical constants (n and k) and related key optical and optoelectronic parameters of PMMA-PS/Ce NPs thin films are reported and interpreted. Furthermore, Tauc and Urbach models are employed to elucidate optical behavior and calculate the band gaps of the as-synthesized nanocomposite thin films. The optical band gap energy of PMMA-PS thin film is found to be 4.03 eV. Optical band gap engineering is found to be possible upon introducing CeO2 NPs into PMMA-PS polymeric thin films as demonstrated clearly by the continuous decrease of optical band gap upon increasing CeO2 content. Fourier-transform infrared spectroscopy (FTIR) analysis is conducted to identify the major vibrational modes of the nanocomposite. The peak at 541.42 cm−1 is assigned to Ce–O and indicates the incorporation of CeO2 NPs into the copolymers matrices. There were drastic changes to the width and intensity of the vibrational bands of PMMA-PS upon addition of CeO2 NPs. To examine the chemical and thermal stability, thermogravimetric (TGA) thermograms are measured. We found that (PMMA-PVA)/CeO2 NPs nanocomposite thin films are thermally stable below 110 °C. Therefore, they could be key candidate materials for a wide range of scaled multifunctional smart optical and optoelectronic devices.

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