Optical characterization of poly (ethylene oxide)/zinc oxide thin films

The optical characterization of poly (ethylene oxide)/zinc oxide thin films has been done by analyzing the absorption spectra in the spectral wavelength region 380-800 nm using a ultraviolet-spectrophotometer at room temperature. Thin film polymer composites made of poly (ethylene oxide) (PEO) containing zinc oxide (ZnO) filler concentrations (0%, 2%, 6%, 10%, and 14%) by weight were used in this study. The optical results obtained were analyzed in terms of the absorption formula for non-crystalline materials. The optical energy gap and other basic optical constants such as dielectric constants and optical conductivity were investigated and showed a clear dependence on the ZnO filler concentration. It was found that the optical energy gap for the composite films is less than that for the neat PEO, and that it decreases as the ZnO concentration increases. Enhancement of the optical conductivity was observed with increase in the ZnO concentration. Dispersion of refractive index was analyzed using the Wemple-DiDomenico single oscillator model. The refractive index (n), extinction coefficient (k), and dispersion parameters (E-o, E-d) were calculated for the investigated films.