Self-Assembly And Controllable Synthesis Of Rare Earth Fluorides

In this thesis, rare earth fluorides YF3:Eu3+, NayYFx:Eu3+and NaYF4:Yb,Er were synthesized in different experimental conditions with silk fibroin as biological template. Then the morphology, crystallinity and luminescent property were characterized and discussed.1. YF3:Eu3+nano-particles were rod in shape, the length was0.5-1.0μm and the diameter was about100nm. All the samples had the characteristic emission peaks of Eu3+The sample prepared only by hydrothermal method had the strongest intensity. The samples belonging to orthorhombic system were well-crystallized. The best doping concentration of Eu3+was11%, the best hydrothermal time was60h.2. Adding different amount of NaF, the as-prepared NayYFx:Eu3+particles were amorphism with dumbbell-like morphology, sphere cubic NaYF4, and cubic and hexagonal NaYF4mixed phase, respectively. The photoluminescent spectrum showed the emission intensity was the strongest when the Y:F ratio was1:3. When the Y:F ratio was1:5, the sample’s emission peaks at555nm,530nm and510nm were enhanced, and there were obvious emission peaks at488nm and465nm.3. Sphere NaYF4:Yb,Er was synthesized with NH4F as the fluorine source. The sizes of these particles were50-500nm. The X-ray diffraction pattern indicated the as-prepared particles were cubic NaYF4. The diffraction peaks attributing to YF3also appeared in the XRD pattern after thermal treatment. The samples displayed red and green emissions when excited by the980nm laser, and the samples prepared only by hydrothermal method had the strongest emission intensity.4. BaLu2Fg:Yb,Er was prepared by hydrothermal microemulsions method. The particles were irregular in shape. The size was about50nm. The samples displayed red and green emissions when excited by the980nm laser.