Optical characterization of poly (ethylene oxide)/alumina composites

The optical properties in the UV-visible region of poly (ethylene oxide) polymer containing 0%, 5%, 10% and 15% by weight aluminum oxide (Al2O3) are reported. The optical results obtained were analyzed in terms of the absorption formula for non-crystalline materials. The absorption coefficient α(ν) and the optical band energy gap (Eopt) have been obtained from direct allowed transitions in k-space at room temperature. The tail widths (ΔE) of the tail of localized states in the band gap were evaluated using the Urbach-edges method. It was found that both (Eopt) and (ΔE) vary with the concentration of the aluminum oxide complex dispersed in the polymer matrix, and the measured optical energy gap for the poly (ethylene oxide) is greater than the PEO/Al2O3 composites. The refractive index (n) for the composites was determined from the collected transmittance and reflectance spectra. The dispersion of the refractive index is discussed in terms of the single oscillator model. The optical energy gaps Eopt, and the optical constants such as refractive index, extinction coefficient and dielectric constant were estimated.