Topotactic Transformation Route to Monodisperse β-NaYF4:Ln3+ Microcrystals with Luminescence Properties

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• 作者：Baiqi Shao ; Yang Feng ; Yan Song ; Mengmeng Jiao ; Wei Lü ; Hongpeng You
• 刊名：Inorganic Chemistry
• 出版年：2016
• 出版时间：February 15, 2016
• 年：2016
• 卷：55
• 期：4
• 页码：1912-1919
• 全文大小：614K
• ISSN：1520-510X

文摘

A novel nonorganic wet route for direct synthesis of uniform hexagonal β-NaYF₄:Ln³⁺ (Ln = Eu, Tb, Ce/Tb, Yb/Er, and Yb/Tm) microcrystals with various morphologies has been developed wherein the intermediate routine cubic–hexagonal (α → β) phase transfer process was avoided. The morphology can be effectively tuned into hexagonal disc, prism, and novel hierarchical architectures by systematically fine manipulating the Na₂CO₃/F^– feeding ratio. It has been found that the routine α → β phase transfer for NaYF₄ was not detected during the growth, while NaY(CO₃)F₂ emerged in the initial reaction stage and fast transformed into β-NaYF₄ via a novel topotactic transformation behavior. Detailed structural analysis showed that β-NaYF₄ preferred the [001] epitaxial growth direction of NaY(CO₃)F₂ due to the structural matching of [001]NaY(CO₃)F₂//[0001]β-NaYF₄. Besides, the potential application of the as-prepared products as phosphors is emphasized by demonstrating multicolor emissions including downconversion, upconversion, and energy transfer (Ce–Tb) process by lanthanides doping.