Synthesis, characterizations, optical and photoluminescence properties of polymer blend PVA/PEG films doped eosin Y (EY) dye

A solution casting process has been used to produce PAV/PEG/EY blend polymer composite films with different PEG concentrations. The structure and morphological of PAV/PEG/EY blend composite film have been characterized by XRD, TGA, FT-IR, TEM,SEM, EDAX and the UV-vis spectra were used to investigate the optical properties. The absorption spectra show a critical change in absorbance around (lambda = 580 nm, photon energy = 2.13ev), which corresponds to the energy gap of the blend. The same behavior of refractive index, n, the extinction coefficient k and dispersion parameters were noticed. Optical energy band gap using Kubelka-Munk coordinate was estimated for direct and indirect allowed transitions, which was found to be 2.58eV for direct transition and 2.47 for indirect transition. The real and imaginary parts of the dielectric constant, epsilon r and epsilon i are quite consistent with the absorption spectra and show a sharp change around lambda = 560 with photon energy = 2.21 eV and corresponds to the average energy gap of the blend. The optical conductivity, sigma opt, was sharply changed at the same value of wavelength. With increasing PEG content in the of PVA/PEG/EY composite samples films, the emission peaks regarding the photoluminescence and fluorescence properties are red shifted, with the highest emission occurred at wavelengths ranges from lambda(em) = 553to575 nm .These values are very close to the energy gap values founded earlier in this work.

Automated summary

The structure, morphology, and optical properties of PAV/PEG/EY blend composite films were investigated, revealing critical changes in absorption spectra at specific wavelengths, corresponding to changes in energy gap and optical properties. The optical conductivity also showed sharp changes at the same wavelength.