Comparative study of Eu³⁺-activated LnOCl (Ln=La and Gd) phosphors and their Judd-Ofelt analysis

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• 作者：N. Dhananjaya^a ; ^{ndhananjayas@bmsit.in" class="auth_mail" title="E-mail the corresponding author} ; C. Shivakumara^b ; ^{shiva@sscu.iisc.ernet.in" class="auth_mail" title="E-mail the corresponding author} ; Rohit Saraf^b ; Sukanti Behera^b ; H. Nagabhushana^c
• 关键词：LaOCl ; GdOCl ; phosphors ; Judd-Ofelt ; CIE ; rare earths
• 刊名：Journal of Rare Earths
• 出版年：2015
• 出版时间：September 2015
• 年：2015
• 卷：33
• 期：9
• 页码：946-953
• 全文大小：1614 K

文摘

Eu³⁺-activated layered LnOCl (Ln=La and Gd) phosphors were synthesized by the conventional solid-state method at relatively low temperature (700 °C) and shorter duration of 2 h. The structural parameters were refined by the Rietveld refinement analysis and confirmed by the high resolution transmission electron microscopy (HRTEM). Both the compounds were crystallized in the tetragonal structure with space group P4/nmm (No. 129). The homogeneity of the elements were analyzed by TEM mapping and found to be uniformly distributed. The photoluminescence spectra revealed that the intensity of ⁵D₀→⁷F₂ transition (619 nm) was more intense in Eu³⁺-activated GdOCl compared to LaOCl. This was due to the property of Gd³⁺ ions to act as an intermediate sublattice to facilitate the energy transfer to Eu³⁺ ions. Intensity parameters and radiative properties such as transition probabilities, radiative lifetime and branching ratio were calculated using the Judd-Ofelt theory. The CIE color coordinates result revealed that the Eu³⁺-activated GdOCl (0.641, 0.354) phosphor was close to the commercial red phosphors like, Y₂O₃:Eu³⁺ (0.645, 0.347), Y₂O₂S:Eu³⁺ (0.647, 0.343) and National Television System Committee (NTSC) (0.67, 0.33). The results suggest that the present GdOCl:Eu³⁺ compound acts as a potential candidate for red phosphor materials.