Institute for Quantum Engineering and Micro-Nano Energy Technology and Faculty of Materials and Optoelectronic Physics, Xiangtan University, Hunan, 411105, China.
Nanoscale. 2010 Dec;2(12):2805-10. doi: 10.1039/c0nr00326c. Epub 2010 Sep 28.
Lanthanide (Ln3+) doped KGdF4 (Ln=Yb3+, Er3+, Ho3+, Tm3+) nanocrystals with a mean diameter of approximately 12 nm were synthesized by a hydrothermal method using oleic acid as a stabilizing agent at 180 °C. The nanocrystals crystallize in the cubic phase as α-NaGdF4. When excited by a 980 nm laser, these Ln3+ doped nanocrystals exhibit multicolor up-conversion (UC) emissions in red, yellow, blue and white. The calculated color coordinates demonstrate that white UC emission (CIE-X=0.352, CIE-Y=0.347) can be obtained by varying the dopant concentrations in the Yb3+/Ho3+/Tm3+ triply-doped nanocrystals to yield different RGB emission intensities. The measured field dependence of magnetization (M-H curves) of the KGdF4 nanocrystals shows their paramagnetic characteristics that can be ascribed to the non-interacting localized nature of the magnetic moment of Gd3+ ions. Moreover, low temperature thermal treatment can enhance UC properties, magnetization and magnetic mass susceptibility of Ln3+ doped KGdF4 nanocrystals. The multifunctional Ln3+ doped KGdF4 nanocrystals have potential applications in color displays, bioseparation, and optical-magnetic dual modal nanoprobes in biomedical imaging.
镧系元素（Ln3+）掺杂的 KGdF4（Ln=Yb3+、Er3+、Ho3+、Tm3+）纳米晶体，平均直径约为 12nm，是通过水热法在 180°C 下使用油酸作为稳定剂合成的。纳米晶体以α-NaGdF4 的立方相结晶。当用 980nm 激光激发时，这些 Ln3+掺杂的纳米晶体在红色、黄色、蓝色和白色中表现出多色上转换（UC）发射。计算出的颜色坐标表明，通过改变 Yb3+/Ho3+/Tm3+三掺杂纳米晶体中的掺杂浓度，可以获得不同的 RGB 发射强度，从而得到白色 UC 发射（CIE-X=0.352，CIE-Y=0.347）。KGdF4 纳米晶体的磁化强度（M-H 曲线）的实测场依赖性表明其具有顺磁性特征，这可归因于 Gd3+离子磁矩的非相互作用局域性质。此外，低温热处理可以增强 Ln3+掺杂 KGdF4 纳米晶体的 UC 性能、磁化强度和磁质量磁化率。多功能 Ln3+掺杂 KGdF4 纳米晶体在彩色显示器、生物分离和生物医学成像中的光学-磁双模纳米探针中有潜在的应用。
