Synthesis and characterization of rare earth doped ceramic phosphors

In this study, the ceramic phosphor materials were synthesized successfully for the first time and then crystal structure and luminescence properties were analyzed. Undoped and Er, Eu, Dy and Sm doped SrAl2O4 phosphors were synthesized. After synthesizing carried out using solid state reaction technique, rare earth doped SrAl2O4 phosphors in the ceramic structure were investigated by means of X-ray diffraction (XRD), Raman scattering, optical absorption, excitation and emission (PL) spectroscopy and thermally stimulated luminescence (TSL). It has been observed that the dominant phase in the crystal belongs to component of SrAl2O4 having typical monoclinic structure and the small amount of doped rare-earth active ions have almost no effect on the basic crystal structure of SrAl2O4 from the XRD patterns of the samples. SEM micrographs taken for Eu and Er doped SrAl2O4 show that samples are found to have crystal structures. Furthermore compared with phosphors prepared via other techniques in the literature, the grain sizes seen here are larger. In this study, Er doped SrAl2O4 sample was synthesized for the first time and absorption bands of Er ions are successfully identified. Photoluminescence emission of Eu doped SrAl2O4 exhibits a strong peak at 620 nm which corresponds orange-red region of the spectrum. In the examined samples, we have observed that photoluminescence emission intensity increase as the concentration of the boron increase. The glow peak curve induced by beta irradiation resembles the glow curve of UV irradiated material, but in detail there are considerable changes in relative peak intensity, as well as displacements of the higher temperature peaks. Photoluminescence intensity of Eu doped sample is higher than that of Dy doped sample but on contrary Dy doped sample gives a strong TSL glow curves after both beta and UV irradiations.