Thermoluminescence, photoluminescence and EPR studies on Mn²⁺ activated yttrium aluminate (YAlO₃) perovskite

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• 作者：H.B. Premkumar^a ; D.V. Sunitha^a ; H. Nagabhushana^a ; ^{bhushanvl@gmail.com} ; S.C. Sharma^a ; B.M. Nagabhushana^b ; C. Shivakumara^c ; J.L. Rao^d ; R.P.S. Chakradhar^e
• 关键词：Phosphor ; Chemical synthesis ; X-ray diffraction ; EPR ; Luminescence
• 刊名：Journal of Luminescence
• 出版年：2012
• 期刊代码：54_00222313
• 类别：ch
• 出版时间：September, 2012
• 卷：132
• 期：9
• 页码：2409-2415
• 文件大小：677 K

摘要

Thermoluminescence (TL) measurements were carried out on undoped and Mn²⁺ doped (0.1 mol%) yttrium aluminate (YAlO₃) nanopowders using gamma irradiation in the dose range 1-5 kGy. These phosphors have been prepared at furnace temperatures as low as 400 掳C by using the combustion route. Powder X-ray diffraction confirms the orthorhombic phase. SEM micrographs show that the powders are spherical in shape, porous with fused state and the size of the particles appeared to be in the range 50-150 nm. Electron Paramagnetic Resonance (EPR) studies reveal that Mn ions occupy the yttrium site and the valency of manganese remains as Mn²⁺. The photoluminescence spectrum shows a typical orange-to-red emission at 595 nm and suggests that Mn²⁺ ions are in strong crystalline environment. It is observed that TL intensity increases with gamma dose in both undoped and Mn doped samples. Four shouldered TL peaks at 126, 240, 288 and 350 掳C along with relatively resolved glow peak at 180 掳C were observed in undoped sample. However, the Mn doped samples show a shouldered peak at 115 掳C along with two well defined peaks at 鈭?15 and 275 掳C. It is observed that TL glow peaks were shifted in Mn doped samples. The kinetic parameters namely activation energy (E), order of kinetics (b), frequency factor (s) of undoped, and Mn doped samples were determined at different gamma doses using the Chens glow peak shape method and the results are discussed in detail.