The role of cobalt amount in ZnCdS nanofiller on the optical, thermal, dielectric and structure properties of PVA/PVP/PEG blends

Abstract

Undoped and doped polyvinyl alcohol (PVA)/ polyvinylpyrrolidone (PVP)/polyethylene glycol (PEG) blends with nano Zn0.75−xCd0.25CoxS (x = 0, 0.05, 0.1, 0.15) were fabricated using a solid state reaction route at low temperature and casting method. Rietveld method was applied to obtain the structure and microstructure properties of the nanofiller Zn0.75−xCd0.25CoxS. X-ray diffraction analysis (XRD), Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM) techniques were used to confirm the presence of the nanofiller in the host blend matrix. The effect of the cobalt contents in the nanofiller on the decomposition temperature and thermal stability of the different blends was explored. The activation energies of different blends were determined using the Coats–Redfern relationship. The different optical parameters and the emitted fluorescence colors of the doped blends were affected by the amount of cobalt (Co) in the nanofiller. The direct and indirect values for an undoped blend are 5.22 and 4.96 eV, respectively. The lowest direct and indirect optical band gap values are 4.13 and 2.13 eV as the amount of Co became 5%. Blends with 5% Co exhibited the highest refractive index. The influence of the cobalt amount in the nanofillers on the electric dielectric constant, ac conductivity and electric modulus of the blends was also investigated.