Effect of annealed ZnS nanoparticles on the structural and optical properties of PVA polymer nanocomposite

PVA/ZnS nano-composites were prepared by both thermolysis and casting procedures. The influence of annealing temperature of ZnS nano filler on the structure properties of composite films was studied by x-ray diffraction and Fourier transform infrared (FTIR) techniques. X-ray analysis revealed that ZnS can be obtained by changing the annealing temperature up to 500 degrees C, above this temperature ZnS converted into ZnO. Moreover, the crystallite size of ZnS increased from 4 to 10 nm as the annealing temperature rose from 300 to 500 degrees C. The effect of crystallite size of nano filler on extinction coefficient, refractive index, band gap, dielectric constant, single-oscillator and the dispersion energies was studied in details using UV-vis. spectrophotometer technique. The photoluminescence technique (PL) showed that, PVA/annealed ZnS nano-composite films exhibited five sub-emissions spectra for ZnS annealed at 300 degrees C and 400 degrees C while the sample contained ZnS annealed at 500 degrees C displayed two sub-emissions. PL intensity enhanced with increasing the crystallite size of ZnS nano particles.