Hydrothermal synthesis of bismuth germanium oxide

Patent metadata

Field	Value
Publication number	US-9518219-B2
Application number	US-201414168543-A
Country	US
Kind code	B2
Filing date	Jan 30, 2014
Priority date	Jan 30, 2014
Publication date	Dec 13, 2016
Grant date	Dec 13, 2016

Abstract

A method for the hydrothermal synthesis of bismuth germanium oxide comprises dissolving a bismuth precursor (e.g., bismuth nitrate pentahydrate) and a germanium precursor (e.g., germanium dioxide) in water and heating the aqueous solution to an elevated reaction temperature for a length of time sufficient to produce the eulytite phase of bismuth germanium oxide (E-BGO) with high yield. The E-BGO produced can be used as a scintillator material. For example, the air stability and radioluminescence response suggest that the E-BGO can be employed for medical applications.

First claim

I claim:

1. A method for the hydrothermal synthesis of bismuth germanium oxide, comprising;
dissolving a bismuth precursor and a germanium precursor in water to provide an aqueous solution, and
heating the aqueous solution in a sealed digestion bomb to a reaction temperature in the range of 150 to 200° C. for a length of time sufficient to produce an eulytite phase of bismuth germanium oxide.

2. The method of claim 1 , wherein the bismuth precursor comprises bismuth nitrate or bismuth acetate.

3. The method of claim 2 , wherein the bismuth nitrate comprises bismuth nitrate pentahydrate.

4. The method of claim 1 , wherein the germanium precursor comprises germanium dioxide.

5. The method of claim 1 , wherein an amount of germanium precursor in excess of the stoichiometric amount is dissolved in the aqueous solution.

6. The method of claim 5 , wherein the excess germanium precursor is removed from the bismuth germanium oxide produced by washing with water or by thermal treatment.

7. The method of claim 1 , wherein the reaction temperature is about 185° C.

8. The method of claim 7 , wherein the aqueous solution is heated to about 185° C. for a length of time greater than 12 hours.

9. The method of claim 1 , wherein the eulytite phase of bismuth germanium oxide is produced with a yield of greater than about 80%.

10. The method of claim 1 , further comprising thermal processing the bismuth germanium oxide produced to a temperature greater than 200° C. to remove trace impurities.

11. The method of claim 3 , wherein the concentration of bismuth nitrate pentahydrate in the aqueous solution is between 0.1 and 0.6 molar.

12. The method of claim 4 , wherein the concentration of germanium dioxide in the aqueous solution is between 0.1 and 0.5 molar.

13. The method of claim 1 , further comprising dissolving a dopant in the aqueous solution to shift the optical emission of the bismuth germanium oxide produced.

14. The method of claim 13 , wherein the dopant comprises a lanthanide dopant.

15. The method of claim 14 , wherein the lanthanide dopant comprises Er 3+ .

Assignees

• Sandia Corp

Inventors

• Boyle Timothy J

Classifications

• C01P2002/88

  by thermal analysis data, e.g. TGA, DTA, DSC · CPC title

• C01P2004/20

  extending in two dimensions, e.g. plate-like · CPC title

• C09K11/7707 Primary

  Germanates · CPC title

• C01P2004/02

  obtained by optical microscopy · CPC title

• C01P2002/77

  by unit-cell parameters, atom positions or structure diagrams · CPC title