Structural Studies of Fluoroborate Laser Glasses by Solid State NMR and EPR Spectroscopies

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• 作者：Ruili Zhang ; Marcos de Oliveira ; Zaiyang Wang ; Roger Gomes Fernandes ; Andrea S. S. de Camargo ; Jinjun RenLong Zhang ; Hellmut Eckert
• 刊名：Journal of Physical Chemistry C
• 出版年：2017
• 出版时间：January 12, 2017
• 年：2017
• 卷：121
• 期：1
• 页码：741-752
• 全文大小：694K
• ISSN：1932-7455

文摘

The structure of glasses in the systems (100 – x)B₂O₃–xPbF₂ (x = 30, 40, and 50) and 50B₂O₃–(50 – x)PbO–xPbF₂ (x = 5, 10, 15, 20, 25, 30, 35, 40, and 45) has been studied by solid state NMR and EPR spectroscopies. On the basis of ¹¹B and ¹⁹F high resolution solid state NMR as well as on ¹¹B/¹⁹F double resonance results, we develop a quantitative structural description on the atomic scale. ¹⁹F NMR results indicate a systematic dependence of the fluoride speciation on PbF₂ content: At low x-values, F^– ions are predominantly found on BO_3/2F^– units, whereas, at higher x-values, fluoride tends to be sequestrated into amorphous domains rich in PbF₂. In addition, both pulsed EPR studies of Yb³⁺ doped glasses and photophysical studies of Eu³⁺ doped samples indicate a mixed fluoride/borate coordination of the rare-earth ions and the absence of nanophase segregation effects.