Synthesis, characterisation, luminescence and defect centres in solution combustion synthesised CaZrOb>3b>:Tb³⁺ phosphor

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• 作者：Vijay Singh^a ; ^{vijayjiin2006@yahoo.com} ; S. Watanabe^b ; T.K. Gundu Rao^b ; Katharina Al-Shamery^c ; Markus Haase^d ; Young-Dahl Jho^a ; ^{jho@gist.ac.kr}
• 关键词：Phosphors ; Combustion ; Tb3+ ; Photoluminescence ; Defect centres
• 刊名：Journal of Luminescence
• 出版年：2012
• 期刊代码：54_00222313
• 类别：ch
• 出版时间：August, 2012
• 卷：132
• 期：8
• 页码：2036-2042
• 文件大小：1265 K

摘要

Tb³⁺ doped CaZrOb>3b> has been prepared by an easy solution combustion synthesis method. The combustion derived powder was investigated by X-ray diffraction, Fourier-transform infrared spectrometry and scanning electron microscopy techniques. A room temperature photoluminescence study showed that the phosphors can be efficiently excited by 251 nm light with a weak emission in the blue and orange region and a strong emission in green light region. CaZrOb>3b>:Tb³⁺ exhibits three thermoluminescence (TL) glow peaks at 126 掳C, 200 掳C and 480 掳C. Electron Spin Resonance (ESR) studies were carried out to study the defect centres induced in the phosphor by gamma irradiation and also to identify the centres responsible for the TL peaks. The room temperature ESR spectrum of irradiated phosphor appears to be a superposition of two distinct centres. One of the centres (centre I) with principal g-value 2.0233 is identified as an O^{鈭?/sup> ion. Centre II with an axial symmetric g-tensor with principal values gb>顚?/sub>=1.9986 and gb>藬b>=2.0023 is assigned to an F+ centre (singly ionised oxygen vacancy). An additional defect centre is observed during thermal annealing experiments and this centre (assigned to F+ centre) seems to originate from an F centre (oxygen vacancy with two electrons). The F centre and also the F+ centre appear to correlate with the observed high temperature TL peak in CaZrOb>3b>:Tb3+ phosphor.}