相和尺寸控制合成稀土离子掺杂的复合氟化物纳米材料及其上转换发光性质研究

Complex fluoride is an important kind of upconversion (UC) host material, for it has high transmission in the visible-infrared range, low phonon energy, good mechanical properties, small variation of refraction index in a wide range of temperature, low hygroscopicity, etc. When the sizes of rare earth doped complex fluorides decrease to nanometer level, the arrangements of atoms in the system will change, which results in change of the specific surface area, surface adsorption properties and crystalline phase. Correspondingly, the optical properties of the complex fluorides will change, too. Researchers have begun exploring the surface effects and phase transitions of rare earth doped complex fluorides. To the best of our knowledge, there is no systematically report on factors of phase transition, sizes and surface of rare earth doped complex fluorides as well as the phase transition effects, small sizes effects, and surface effects on the optical properties. There is also no study on the effects of surface effects, phase transition mechanism, and sizes control mechanism on the development and research of devices. The phase transition, small size effects, and surface effects problem is the first problem to be solved for the research on nano-devices. By using combined mciroemusion method and solvothermal method, we have the plan to synthesis rare earth doped complex fluorides nano-materials and research the factor of phase transition, small sizes effects, and surface effects on the UC emissions of the complex fluorides. The project will lay the research foundation of materials with friendly environment, stable property, and long lifetime which can be used in UC biological virus apparatus and optical communications.

复合氟化物是一类重要的上转换发光基质材料。它们具有从可见光-红外光范围内透光率高、声子能量低、机械性能好、折射率在很宽的温度范围内变化不大和吸水性小等特点。然而，当稀土掺杂复合氟化物材料的空间尺寸减小到纳米量级时，晶体中原子排列方式发生改变，从而它们的比表面积、表面吸附性能和物相发生变化而导致其光物理性质发生变化。人们已经开始研究稀土掺杂复合氟化物纳米材料表面效应和相变现象。迄今为止，未见系统研究引起稀土掺杂复合氟化物的相、尺寸及表面效应与光学性质的文献报道，更没出现材料相变对器件开发研究方面的文献报道。稀土离子掺杂复合氟化物纳米材料的表面效应和物相、尺寸控机制是纳米器件研究的首要解决的基本问题。本项目拟采用微乳和溶剂热结合技术制备相、尺寸可控的稀土掺杂复合氟化物纳米材料，研究其相变、小尺寸效应及表面效应对其上转换发光性质的影响。为开发性能优良、环境友好的生物病毒检测和光通讯器材奠定基础。

具有蓝色、绿色上转换发光性能的β-Na(Y1.5-x-yNa0.5)F6:YbxTmy and Ca(1-x-y)F2:Ybx,Ery纳米颗粒被水热法合成，并研究和讨论了Yb3+ 和 Tm3+ (Er3+)掺杂浓度对其发光性能的影响。.沉淀转化法把La(OH)3: 20%Yb3+, 0.1%Ho3+, 1%Tm3+纳米棒转化为单分散的LaF3:20%Yb3+, 0.1%Ho3+, 1%Tm3+纳米颗粒。同时调节样品的红、绿、蓝色光的比例而得到了较宽的激发功率下均发白色光的纳米材料。.热分解法合成了单分散、形貌均一的空心结构NaYF4 :Yb,Er和GdF3:Yb,Er纳米材料。我们采用盐酸氧化法把油溶性的NaYF4 :Yb,Er和GdF3:Yb,Er纳米材料转化了水溶性的纳米材料。这类纳米材料在药物输运和生物成像领域具有潜在的应用。.在高沸点有机溶剂油酸为配体，十八烯为稳定剂的混合溶液中共热Gd(CF3COO)3和CF3COONa的方法制备出了α-NaGdF4:Yb0.2Er0.02、自组装的α-NaGdF4:Yb0.2Er0.02和高分辨结构的β-NaGdF4:Yb0.2Er0.02纳米颗粒。结果表明：通过改变CF3COONa/Gd(CF3COO)3的比例、反应温度等，可以有效的控制纳米颗粒的物相、上转换发光强度及自组装α-NaGdF4纳米颗粒的形态演变。.采用热分解法控制合成了一系列形貌规则的四方相LiYF4:Yb0.2Er0.02纳米颗粒并具体研究了反应条件对产物性能的影响。结果说明：反应时间和浓度决定了样品的尺寸、形貌、结晶性等，且样品的上转换发光强度随其尺寸大小增大而增强。当反应溶剂为油酸、十八烯混合溶液时制备出的样品比油酸、油胺、十八烯体系时尺寸变大，发光明显增强。.热分解法制备了BaZnF4 （Ba2GdF7）: Er3+, Yb3+等纳米材料，并用XRD、TEM和荧光光谱仪研究了其晶体结构、形貌和上转换发光性能。.通过TEM、HRTEM、XRD和日立F-4600荧光分光光度计进行了样品的表征。