Method to enhance phosphor robustness and dispersability and resulting phosphors

Patent metadata

Field	Value
Publication number	US-11261375-B2
Application number	US-201916419206-A
Country	US
Kind code	B2
Filing date	May 22, 2019
Priority date	May 22, 2019
Publication date	Mar 1, 2022
Grant date	Mar 1, 2022

Abstract

Briefly, in one aspect, the present invention relates to processes for producing a stabilized Mn4+ doped phosphor in solid form and a composition containing such doped phosphor. Such process may include combining a) a solution comprising at least one substance selected from the group consisting of: K2HPO4, an aluminum phosphate, oxalic acid, phosphoric acid, a surfactant, a chelating agent, or a combination thereof, with b) a Mn4+ doped phosphor of formula I in solid form, where formula I may be: Ax [MFy]:Mn4+. The process can further include isolating the stabilized Mn4+ doped phosphor in solid form. In formula I, A may be Li, Na, K, Rb, Cs, or a combination thereof. In formula I, M may be Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Y, La, Nb, Ta, Bi, Gd, or a combination thereof. In formula I, x is the absolute value of the charge of the [MFy] ion and y is 5, 6 or 7.

First claim

The invention claimed is:

1. A process comprising combining a) a solution comprising at least one substance selected from the group consisting of: K 2 HPO 4 , an aluminum phosphate, oxalic acid, or a combination thereof, and optionally, a surfactant or a chelating agent, with b) a Mn 4+ doped phosphor of formula I in solid form;
A x [MF y ]:Mn 4+   I

and isolating a stabilized Mn 4+ doped phosphor in solid form; wherein A is Li, Na, K, Rb, Cs, or a combination thereof; M is Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Y, La, Nb, Ta, Bi, Gd, or a combination thereof; x is the absolute value of the charge of the [MF y ] ion; y is 5, 6 or 7.

2. The process according to claim 1 , further comprising, prior to combining with the at least one substance, contacting the Mn 4+ doped phosphor of formula I with a fluorine-containing oxidizing agent in gaseous form at an elevated temperature, to form a product phosphor.

3. The process according to claim 1 , wherein M is Si, Ge, Ti, or a combination thereof; A is Na, K, or a combination thereof.

4. The process according to claim 1 , wherein the phosphor of formula I is K 2 SiF 6 :Mn 4+ .

5. The process according to claim 1 , wherein the at least one substance comprises K 2 HPO 4 .

6. The process according to claim 1 , wherein the at least one substance comprises the surfactant and K 2 HPO 4 .

7. The process according to claim 1 , wherein the solution is aqueous and additionally comprises H 2 O 2 .

8. The process according to claim 1 , wherein the solution additionally comprises at least one solvent selected from the group consisting of: 1-octadecene, isonorbornyl acrylate, water, and propylene glycol monomethyl ether acetate.

9. The process according to claim 6 , wherein the surfactant comprises at least one selected from the group consisting of: polyoxyethylene octyl phenyl ether, potassium oleate, polyoxyethylene-polyoxypropylene block copolymer; polyoxyethylene (20) sorbitan monolaurate, poly(acrylic acid sodium salt), and potassium sorbate.

10. A process comprising combining a) a solution comprising at least one substance selected from the group consisting of: K 2 HPO 4 , an aluminum phosphate, oxalic acid, phosphoric acid, or a combination thereof, and optionally, a surfactant or a chelating agent, with b) a Mn 4+ doped phosphor of formula I in solid form:
A x [MF y ]:Mn 4+   I

and isolating a stabilized Mn 4+ doped phosphor in solid form: wherein A is Li, Na, K, Rb, Cs, or a combination thereof: M is Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Y, La, Nb, Ta, Bi, Gd, or a combination thereof: x is the absolute value of the charge of the [MF y ] ion: y is 5, 6 or 7,
wherein the Mn 4+ doped phosphor of formula I comprises a core comprising a phosphor of formula I and a manganese-free composite coating disposed on the core, the manganese-free composite coating comprising a compound of formula III and a metal fluoride selected from the group consisting of calcium fluoride, strontium fluoride, magnesium fluoride, yttrium fluoride, scandium fluoride, lanthanum fluoride, and combinations thereof,
A 1 x [M 1 F y ]  (III)

wherein A 1 is H, Li, Na, K, Rb, Cs, or a combination thereof; M 1 is Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Y, La, Nb, Ta, Bi, Gd, or a combination thereof; x is the absolute value of the charge of the [M 1 F y ] ion; and y is 5, 6 or 7.

11. A composition comprising a) at least one substance selected from the group consisting of: K 2 HPO 4 , an aluminum phosphate, oxalic acid, or a combination thereof, and b) a Mn 4+ doped phosphor of formula I;
A x [MF y ]:Mn 4+   I

wherein A is Li, Na, K, Rb, Cs, or a combination thereof; M is Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Y, La, Nb, Ta, Bi, Gd, or a combination thereof; x is the absolute value of the charge of the [MF y ] ion; y is 5, 6 or 7.

12. The composition according to claim 11 , wherein M is Si, Ge, Ti, or a combination thereof; A is Na, K, or a combination thereof.

13. The composition according to claim 11 , wherein the phosphor of formula I is K 2 SiF 6 :Mn 4+ .

14. The composition according to claim 11 , wherein the at least one substance comprises K 2 HPO 4 and magnesium fluoride.

15. A composition comprising a) at least one substance selected from the group consisting of: K 2 HPO 4 , an aluminum phosphate, oxalic acid, phosphoric acid, or a combination thereof, and b) a Mn 4+ doped phosphor of formula I;
A x [MF y ]:Mn 4+   I

wherein A is Li, Na, K, Rb, Cs, or a combination thereof; M is Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Y, La, Nb, Ta, Bi, Gd, or a combination thereof; x is the absolute value of the charge of the [MF y ] ion; y is 5, 6 or 7,
wherein the Mn 4+ doped phosphor of formula I comprises a core comprising a phosphor of formula I and a manganese-free composite coating disposed on the core, the manganese-free composite coating comprising a compound of formula III and a metal fluoride selected from the group consisting of calcium fluoride, strontium fluoride, magnesium fluoride, yttrium fluoride, scandium fluoride, lanthanum fluoride, and combinations thereof,
A 1 x [M 1 F y ]  (III)

wherein A 1 is H, Li, Na, K, Rb, Cs, or a combination thereof; M 1 is Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Y, La, Nb, Ta, Bi, Gd, or a combination thereof; x is the absolute value of the charge of the [M 1 F y ] ion; and y is 5, 6 or 7.

16. A display device comprising a stabilized Mn 4+ doped phosphor produced by the process according to claim 1 .

17. The display device according to claim 16 , wherein the display device comprises a television, a computer monitor, a cellular or conventional phone, a digital photo frame, a tablet, an automotive display, an e-book reader, an electronic dictionary, a digital camera, an electronic keyboard, or a gaming device.

18. A lighting apparatus comprising a stabilized Mn 4+ doped phosphor produced by the process according to claim 1 .

19. A phosphor composition comprising phosphor particles and comprising, on surfaces of the phosphor particles, at least one surface composition selected from the group consisting of: 1) a composition comprising a phosphorus-containing moiety and a carbon-containing moiety; 2) a composition comprising the phosphorus-containing moiety and a metal fluoride; 3) a composition comprising the phosphorus-containing moiety and the carbon-containing moiety and the metal fluoride; and 4) a composition comprising the phosphorus-containing moiety free of an alkyl phosphate compound, wherein the phosphor particles comprise a Mn 4+ doped phosphor of formula I;
A x [MF y ]:Mn 4+   I

wherein A is Li, Na, K, Rb, Cs, or a combination thereof; M is Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Y, La, Nb, Ta, Bi, Gd, or a combination thereof; x is the absolute value of the charge of the [MF y ] ion; y is 5, 6 or 7, and
wherein a D 50 particle size of the phosphor particles before sonication of a suspension containing the particles is no greater than 30 μm and the D 50 particle size of the phosphor particles after sonication is no greater than 20 μm.

20. The phosphor composition according to claim 19 , wherein the metal fluoride comprises magnesium fluoride.

21. The phosphor composition according to claim 19 , wherein the phosphorus-containing moiety comprises a phosphate moiety.

22. The phosphor composition according to claim 19 , wherein the carbon-containing moiety comprises at least one selected from the group consisting of: ethylenediaminetetraacetic acid, polyoxyethylene octyl phenyl ether, potassium oleate, p

Assignees

• Gen Electric

Inventors

• Butts Matthew David
• Murphy James Edward
• Doherty Mark Daniel

Classifications

• C09K11/025 Primary

  non-luminescent particle coatings or suspension media · CPC title

• H10H20/8512

  Wavelength conversion materials · CPC title

• H10H20/851

  Wavelength conversion means · CPC title

• H10H20/8515

  not being in contact with the bodies · CPC title

• H10H20/0361

  of wavelength conversion means · CPC title