Growth, structural and optical characterizations of LiLa_{(1鈭?span style='font-style: italic'>x)}Eu_x(WO₄)₂ single-crystalline fibers by the micro-pulling-down method

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• 作者：Jair Ricardo de Moraes^a ; Sonia Licia Baldochi^a ; ^{baldochi@ipen.br} ; ^{jairric@yahoo.com.br} ; Leonardo dos Reis Leano Soares^a ; Vera Lucia Mazzocchi^a ; Carlos Benedicto Ramos Parente^a ; Lilia Coronato Courrol^b
• 关键词：A. Oxides ; B. Crystal growth ; D. Crystal structure ; D. Luminescence ; D. Optical properties
• 刊名：Materials Research Bulletin
• 出版年：2012
• 期刊代码：60_00255408
• 类别：ms
• 出版时间：March, 2012
• 卷：47
• 期：3
• 页码：744-749
• 文件大小：1236 K

摘要

Transparent and uniform LiLa_(1鈭?em>x)Eu_x(WO₄)₂ single-crystalline fibers where x = 0.005, 0.01, 0.03, 0.05, 0.07, 0.1, 0.15, 0.2, 0.25 and 1.0, with an average of 20-40 mm length were obtained by the micro-pulling-down method aiming structural and optical characterization. The optimum pulling rate was found to depend on the difference between alkali and rare earth ionic radii. Rietveld analysis from X-ray diffraction data and excitation spectroscopy at room temperature were applied to investigate the lattice changes due to the Eu³⁺ incorporation in the host. LiLa_(1鈭?em>x)Eu_x(WO₄)₂ crystal fibers present red emission due to the electric dipole ⁵D₀ 鈫?#xA0;⁷F₂ transition under 395 nm excitation showing a concentration quenching around 20 mol%of doping. The excitation spectra of the ⁷F₀ 鈫?#xA0;⁵D₀ transition show small changes in the Eu³⁺ surroundings as function of dopant concentration.