Photoelectric Functional Material - Barium Tungstate

Barium tungstate (BaWO₄) is one of the divalent metal tungstate, which is an important photoelectric functional material. Barium tungstate crystal is a promising Raman laser crystal due to its stimulated Raman scattering. Barium tungstate crystal can be used in all solid state lasers, and it is possible to design it to emit radiation in special spectral region. Barium tungstate crystal has important application value in many fields, such as photoelectricity, medicine, spectroscopy, because of its special characteristics of photoluminescence, thermoluminescence and stimulated Raman scattering.

Barium tungstate crystal belongs to body centered tetragonal scheelite structure, space group I41 / A, point group C₄H₆, molecular weight of barium tungstate 385.19. Colorless tetragonal crystal. The relative density is 5.0415. Slightly soluble in water, soluble in ammonium nitrate solution. It can be decomposed by boiling inorganic acid to form yellow tungsten trioxide. There are two preparation methods of barium tungstate, the details are as follows:

Method 1: barium tungstate was obtained by heating the mixture of tungsten trioxide and barium carbonate, or by separating barium tungstate (H₅BW₁₂O₄₀) from boiled barium hydroxide aqueous solution.

Method 2: using sodium tungstate and barium nitrate as the starting reactant, citric acid as the metal ion complexing agent and guiding agent, distilled water as the solvent, using microwave radiation technology, the specific operation scheme is as follows:

1)At room temperature, accurately weigh 0.1649 g of sodium tungstate (NaWO₄·2H₂O) solid, add 10 ml of distilled water to prepare a specific concentration of sodium tungstate solution;

2)Weigh 0.1307 g of barium nitrate (Ba(NO₃)₂) and 0.0105 g of citric acid, add 10 ml of water, stir at high speed for 5 minutes, and prepare the mixed solution;

3)Transfer the solution in step 1) to the solution in step 2, and continue stirring for 10 minutes;

4)Put the mixed solution in microwave reactor for 30 minutes and stop the reaction;

5) The porous shuttle type barium tungstate material can be obtained by natural cooling, washing 3~5 times with distilled water and absolute alcohol, and vacuum drying at 60 ℃ for 48 hours.

The unique crystal structure of barium tungstate endows the material with superior luminescent and stimulated Raman scattering properties, so it can be used as a good optical material or laser donor material, and has important application value and development prospect in the fields of optoelectronics, medicine, laser sensor, etc.

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