Synthesis of uniform rare earth fluoride (NaMF4) nanotubes by in situ ion exchange from their hydroxide [M(OH)3] parents.
Synthesis of uniform rare earth fluoride (NaMF4) nanotubes by in situ ion exchange from their hydroxide [M(OH)3] parents.
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DOI：
10.1021/nn800533v
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发表时间：
2009-01
期刊：
影响因子：
17.1
通讯作者：
Fan Zhang;Dongyuan Zhao
中科院分区：
文献类型：
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作者：
Fan Zhang;Dongyuan Zhao
本文以稀土氢氧化物[M（OH）（3）]为母体，通过水热原位离子交换反应制备了均匀的六方晶系稀土氟化物钠（beta-NaMF（4））纳米管。三价稀土氢氧化物在120 ℃水热条件下制备，具有准层状结构，可以通过二维片的卷起过程形成纳米管形态。此外，稀土氢氧化物[M（OH）（3）]的六方结构显示出与β-NaMF（4）的显著相似性。这种相似性使得通过具有层状结构的M（OH）（3）的原位化学转化形成具有非层状结构的β-NaMF（4）成为可能。合成了单晶β-NaMF（4）纳米管，其直径（80-500 nm）、长径比（6-30）、壁厚（25-80 nm）和含量（如M = Pr，Sm，Gd，Tb，Dy，Er，以及镧系元素掺杂的稀土NaMF（4））得到了很好的控制。Yb（3+）/Er（3+）（绿色）和Yb（3+）/Tm（3+）（蓝色）共掺杂β-NaMF（4）纳米管在近红外波段的紫外光激发下也实现了上转换荧光。研究了样品的各种UC发射率作为水热反应时间的函数，以研究产物的UC性质，并进一步证明水热原位离子交换过程。
In this article, we demonstrate the production of uniform hexagonal sodium rare earth fluoride (beta-NaMF(4)) nanotubes through a hydrothermal in situ ion-exchange reaction by using rare earth hydroxides [M(OH)(3)] as a parent. The trivalent rare earth hydroxides were hydrothermally prepared at 120 degrees C and possessed a quasi-layered structure, which could be formed to be nanotubal morphology through a rolling up process from 2-D sheets. Moreover, the hexagonal structure of rare earth hydroxides [M(OH)(3)] displays a noticeable similarity with beta-NaMF(4). This similarity makes the formation of beta-NaMF(4) with nonlayered structure possible through in situ chemical transformation from M(OH)(3) with a layered structure. The single-crystal beta-NaMF(4) nanotubes were synthesized with well-controlled diameter (80-500 nm), aspect ratio (6-30), wall thickness (25-80 nm), and contents (such as M = Pr, Sm, Gd, Tb, Dy, Er, as well as lanthanide-doped rare earth NaMF(4)). The multicolor upconversion fluorescence has also been successfully realized in the Yb(3+)/Er(3+) (green) and Yb(3+)/Tm(3+) (blue) co-doped beta-NaMF(4) nanotubes by UC excitation in the NIR region. The various UC emission ratios of the samples were investigated as a function of hydrothermal reaction time to research the UC properties of the products and to further demonstrate the hydrothermal in situ ion-exchange process.