Preparation, luminescence and defect studies of Eu-activated strontium hexa-aluminate phosphor prepared via combustion method

Preparation of Eu²⁺ ions activated strontium hexa-aluminate phosphor using the combustion method is described. An efficient phosphor can be prepared by this method at reaction temperatures as low as 500 °C in a few minutes. Powder X-ray diffraction (XRD), transmission electron microscopy, scanning electron microscope analysis were used to characterize the as prepared product and the optical properties were studied by photoluminescence (PL) spectra. Thermally stimulated luminescence studies also have been carried out on SrAl₁₂O₁₉:Eu²⁺ phosphor. The TSL glow curve is broad and indicates two dominant peaks at 206 and 345 °C. Defect centres formed in irradiated phosphor have been studied using the technique of electron spin resonance. One of the centres is characterized by an isotropic g-value of 2.0055 and is assigned to a F⁺ centre. The two annealing stages of F⁺ centre in the region 125-230 and 340-390 °C appear to correlate with the release of carriers resulting in TSL peaks at 206 and 345 °C, respectively.