不同形貌Eu掺杂稀土氟化物的水热合成及荧光性能

Hydrothermal Synthesis and Fluorescence Properties of Eu-doped Rare Earth Fluorides with Various Morphologies

以不同的辅助剂为形貌控制剂,采用简单的水热法合成了八面体形、梭形体、苦瓜状和纳米微球状稀土氟化物,并对其结构和性能进行了表征。X射线衍射(XRD)和扫描电子显微镜(SEM)结果表明辅助剂不同,产物的物相和形貌也不同。在没有辅助剂的情况下,得到八面体形正交晶系YF_3;以柠檬酸和无水乙醇为辅助剂时,分别得到纳米须自组装而成的梭状体和纳米粒自组装而成的苦瓜状正交晶系YF_3;而以乙二胺四乙酸(EDTA)-2Na为辅助剂时,得到的样品为立方相NaYF_4纳米微球。对氟化物的生长机理进行了探讨,并研究了其荧光性能。荧光光谱表明:正交晶系YF_3∶Eu^(3+)的最强发射峰均位于593nm,对应Eu^(3+)的~5D_0→~7F_1的磁偶极跃迁发射,但不同形貌对应的发射峰强度不一样。而立方相NaYF_4的发射光谱图包含了Eu^(3+)从激发态~5D_(0-2)到基态~7F_J的发射峰。

Octahedral,spindle,balsam pear-shaped and nanosized microsphere-shaped rare earth fluorides were prepared by hydrothermal method using different additives as morphology-controlling agents.The structure,morphology and fluorescence properties of the samples were characterized by XRD,SEM,and fluorescence spectroscopy.XRD patterns and SEM images indicated that the samples obtained by using different additives had different structures and morphologies.The as-synthesized sample was pure orthogonal phase of octahedral YF_3 without any additive,however,nano-whisker of self-assembled spindle-shaped YF_3 and nano-particle of self-assembled balsam pear-shaped YF_3 were obtained with citric acid and ethanol as additives respectively.The nanosized microsphere of cubie phase NaYF_4 was formed with ethylene diamin tetracicetic acid(EDTA)_2Na as additive.The growth mechanism and luminescence properties were described.It was found that the strongest emission peak of the orthogonal phase YF_3∶Eu^(3+) was near 593 nm,corresponding to 5 D0→7F1 magnetic dipole transition of Eu^(3+).The emission intensities varied with different morphologies.The emission spectrum of the cubic phase NaYF4 included all the emission peaks of Eu^(3+) from the emission state of ~5D_(0-2) to the ground state of ~7F_J.