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Crystal : BY2F8

Material science and Technology

? We mainly talk about the structure and properties of BY2F8 crystal. ? The methods of synthesizing BY2F8 powder and growing crystal. ? The application of BY2F8 crystal.

Structure
? The symmetry of the BYF crystal is monoclinic. The Y3+ ion lattice site is surrounded by eight F anions forming slightly deformed Thompson cube. Yttrium polyhedral, sharing a common edge, form parallel (0 0 1) planes consisting of sixsegmented rings.

Properties
? The BaY2F8(BYF) single crystal doped with trivalent rare-earth ions has recently attracted a lot of attention because of its potential application as : ? 1.VUV scintillators(闪烁计数器) ? 2.Media for solid-state lasers in VUV and IR ? 3.New efficient phosphors for plasma display panels ? 4.Luminescent lamps based on rare-gas discharges

VUV scintillators

plasma display panels

Preparation
? Materials:
We choose high purity (>99.99%) materials. Y2O3, BaCO3 ,NH4F

Preparation
? Methods for Powder: ? 1. Hydrothermal synthesis method (水热合 成法) ? 2. Coprecipitation method (共沉淀法) ? 3. Sol gel method(溶胶凝胶法) ? 4. Solvent hot method (溶剂热法)

Methods for growing crystal:
? 1.Cz method
? 2.Temperature gradient method ? 3. Bridgman method ? 4. Kyropoulos method (泡生法)

Cz method
? Due to rich experiment and well mastering We mainly use Cz methods. The picture of Cz device is shown:

Heating methods

? 1. Resistance wire heating ? 2. Medium frequency induction heating

Rescent Rearch
? At present, the 1.88um fluorescence emission has been came true of BYF doped Tm3+

? Above we introduce the basic situation of BYF.

That is all.



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