Synthesis, characterization and luminescent properties of needle-like lanthanide-doped orthorhombic Y5O4F7

Thermal annealing of YOH1.1F1.9 and YOH1.1F1.9:Ln3+(Ln3+=Eu3+,Tb3+ and Gd3+) precursors in air gave access to synthesize yttrium oxyfluoride phosphors with well-preserved needle-like morphologies. The phase purities of samples strongly depended on the thermal annealing temperature. At 600 °C, pure Y5O4F7 with orthorhombic structure were obtained, as evidenced by powder X-ray diffraction measurement and chemical analysis. The interesting microstructure evolution of the annealed sample from well-organized nanoparticles on curly slices to microrod-bundle structure had been aroused by raising annealing temperature. The multicolor fluorescent emissions of Y5O4F7:Ln3+ phosphors were observed, e.g. ultraviolet emission for Gd3+ , green emission for Tb3+ and red emission for Eu3+ , which resulted from characteristic transitions of different lanthanide ions.     

Synthesis,structure and luminescent properties of a new Vernier phase Lu7O6F9 doped by Eu^3＋ as potential scintillator with unique lath tube architecture

To explore novel nano-scintillator with a controllable architecture, pure and Eu3+ doped lutetium oxyfluoride(Lu7O6F9) powder were synthesized by combining mild hydrothermal method and solid state calcination approach. The products were all pure orthorhombic Vernier phase demonstrated by X-ray powder diffraction(XRD). The detailed crystal structure was also studied by Reitveld refinement. Lath-like microcrystals composed of nanoparticles with unique hollow tube of the products were supported by the images of scanning electron microscopy(SEM) and transmission electron microscopy(TEM). Excited by X-ray with W as the target, the pure product showed intense broad emission with the peak at about 400 nm suitable for modern photoelectric multiplier tube(PMT), while the Eu3+ doped sample transferred the incident energy to Eu3+ ions and gave strong 5D0→7Fj(j=0, 1, 2 and 4) emission, which fitted for imaging and labeling measurements. From the luminescent properties, both pure and Eu3+-doped products are potential excellent scintillator for X-ray imaging and other high energy detectors, and the pure product is also a good host candidate for rare earth doping.