High quality multi-functional NaErF4 nanocrystals: structure-controlled synthesis, phase-induced multi-color emissions and tunable magnetic properties
High quality multi-functional NaErF4 nanocrystals: structure-controlled synthesis, phase-induced multi-color emissions and tunable magnetic properties
复制标题
高品质多功能NaErF4纳米晶体：结构控制合成、相诱导多色发射和可调磁性能
DOI：
10.1039/c3tc30796d
复制
发表时间：
2013-08
影响因子：
6.4
通讯作者：
Zeng, Songjun
中科院分区：
文献类型：
--
作者：
Yi, Zhigao;Rao, Ling;Liu, Hongrong;Zeng, Songjun
本文以油酸为封盖剂，采用简单的水热法制备了高质量、不同相、不同形状的光/磁多功能NaErF4纳米晶体。通过各种技术对其结构、上转换发光和磁性能进行了表征。透射电镜结果表明，纳米晶体质量高，可自组装成二维有序结构。此外，通过调节反应温度和F−含量可以很容易地控制晶体的相和形状。结果表明，高温有利于六方相结构的形成，促进了立方相向六方相的转变。详细讨论了基于自由能理论的相变机理。此外，F−的含量在决定最终产物的形貌方面起着关键作用。高的F−含量有利于一维棒状结构的形成。有趣的是，观察到相位诱导的上转换发光颜色从红色到绿色。所有制备的NaErF4纳米晶体在室温下都具有顺磁性，球状立方、立方和棒状纳米晶体的磁化强度分别为1.69 emu g−1、2.53 emu g−1和2.29 emu g−1，比之前报道的大多数基于gd的纳米晶体都要大。此外，还首次证实了基于这些NaErF4纳米晶体的t2加权磁共振成像。因此，这些具有优异顺磁性能的可调谐上转换荧光NaErF4纳米晶体可作为光学生物成像和磁共振成像的双模态纳米探针，在生物分离领域具有潜在的应用前景。
In this paper, optical/magnetic multi-functional NaErF4 nanocrystals with high quality, different phases and shapes were synthesized by a simple hydrothermal method using oleic acid as the capping agent. The structure, upconversion luminescence and magnetic properties were characterized by various techniques. The transmission electron microscopy results reveal that the nanocrystals are of high quality and can be self-assembled into a two-dimensional ordered structure. Moreover, the crystal phase and shape can be readily controlled by adjusting the reaction temperature and F− content. The results reveal that high temperature can favor the formation of a hexagonal phase structure and promote the phase transformation from the cubic to hexagonal phase. The phase transformation mechanism based on the free energy theory was discussed in detail. In addition, the F− content plays a critical role in determining the morphology of the final products. A high F− content is beneficial for the formation of the one-dimensional rod-like shape. Interestingly, phase-induced upconversion luminescence color tuning from red to green was observed. All of the as-prepared NaErF4 nanocrystals possess paramagnetic properties at room temperature and the magnetizations of the nanocrystals with spherical-like cubic, cubic, and rod-like shapes were measured as 1.69 emu g−1, 2.53 emu g−1and 2.29 emu g−1 at 20 kOe, respectively, which are larger than most previously reported Gd-based nanocrystals. In addition, T2-weighted magnetic resonance imaging based on these NaErF4 nanocrystals was demonstrated for the first time. Therefore, these tunable upconversion fluorescent NaErF4 nanocrystals with excellent paramagnetic properties can be used as promising dual-modal nanoprobes for optical bioimaging and magnetic resonance imaging, and may have potential applications in bioseparation.
登录
查看更多内容
钠稀土氟化物纳米晶的高均匀性和单分散性：可控合成、形状演化和光学性质
影响因子：
3.1
作者：
通讯作者：
--
镧系元素掺杂 KLaF4 纳米晶的控制合成与光谱
影响因子：
6.7
作者：
Liu, Rui;Tu, Datao;Chen, Xueyuan
通讯作者：
Chen, Xueyuan
影响因子：
19
作者：
Liang, Xin;Wang, Xun;Li, Yadong
通讯作者：
Li, Yadong
影响因子：
6.7
作者：
Boyer, John-Christopher;van Veggel, Frank C. J. M.
通讯作者：
van Veggel, Frank C. J. M.
影响因子：
14
作者：
Xingjun Zhu;Jing Zhou;Min Chen;Mei Shi;Wei Feng;Fuyou Li
通讯作者：
Xingjun Zhu;Jing Zhou;Min Chen;Mei Shi;Wei Feng;Fuyou Li