Annealing effect on the structural, optical and thermoluminescent properties of ZnAl2O4:Cr3+

The nanocrystalline phosphor of ZnAl2O4:Cr3+ has been prepared by the hydrothermal method.which utilizes the adjournment of cationic precursors in a urea aqueous solution. The as-prepared sample was annealed at different temperatures and the effect of thermal annealing with Cr3+ impurity ions on the structural, optical and thermoluminescence properties of the obtained samples was investigated. X-ray diffraction (XRD) and transmission electron microscopy (TEM), UV-Vis spectroscopy, Photoluminescence (PL), Fourier transform infra -red spectroscopy (FTIR) and Thermo luminescence cm were used for the characterizations of the materials. From the XRD analysis, it is found that with increasing temperature, the crystallite size and lattice constants of the samples are increased. The morphological changes have been also observed by TEM. The variation in the optical properties showed that the PL emission peaks observed which corresponds to Cr3+ ions. The FTIR spectrum exhibits the transmission band of Al-O octahedral groups. The change in thermoluminescence (II) glow curves characteristics of all the phosphors samples was also studied. A prominent glow peak at 428 K was observed in the TSL of gamma-irradiated Cr3+-doped ZnAl2O4 phosphors. Thus, the crystal structure, particle size and morphology were found to depend on the precursors, method of synthesis and annealing temperature. (C) 2017 Elsevier B.V. All rights reserved.