# US 9,868,898 B2 · Processes for preparing color stable red-emitting phosphors

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- Number: US 9,868,898 B2
- Document ID: US9868898B2
- Status: Granted
- Kind: B2
- Application number: 15/197,897
- Filed: 2016-06-30
- Published: 2016-10-27
- Granted: 2018-01-16
- Earliest claimed: 2013-03-15
- Assignees: General Electric Company
- Applicants: General Electric Company
- Inventors: James Edward Murphy; Fangming Du; Anant Achyut Setlur
- Web page: https://patentgrep.com/patent/US9868898B2

## CPC

- C09K 11/616: {with alkali or alkaline earth metals}
- C09K 2211/181: of the alkali metals and alkaline earth metals
- C09K 2211/188: of other metals not provided for in one of the previous groups
- H10H 20/8512: {Wavelength conversion materials}
- H10W 74/00: Encapsulations, e.g. protective coatings
- H10W 90/756: {between a chip and a stacked lead frame, conducting package substrate or heat sink}
- C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- H10H: INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10

## Abstract

Processes for preparing color stable Mn4+ doped phosphors include contacting a phosphor of formula I with a fluorine-containing oxidizing agent in gaseous form at temperature ≦225° C. to form the color stable Mn4+ doped phosphor A x ⁢ MF y ⁢ : ⁢ Mn 4 + I wherein A is independently at each occurrence Li, Na, K, Rb, Cs, or a combination thereof; M is independently at each occurrence Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Hf, Y, La, Nb, Ta, Bi, Gd, or a combination thereof; x is the absolute value of the charge of the MFy ion; and y is 5, 6 or 7. In another aspect, the processes include contacting a phosphor of formula I at an elevated temperature with an oxidizing agent comprising a C1-C4 fluorocarbon, to form the color stable Mn4+ doped phosphor.

## Claims

### Claim 1

A process for synthesizing a color stable Mn4+ doped phosphor, the process comprising
contacting a phosphor of formula I,
A
x
⁢
MF
y
⁢
:
⁢
Mn
4
+
I
with a fluorine-containing oxidizing agent in gaseous form at a temperature from 90° C. to less than 225° C. to form the color stable Mn4+ doped phosphor;
wherein
A is Li, Na, K, Rb, Cs, or a combination thereof;
M is Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Hf, Y, La, Nb, Ta, Bi, Gd, or a combination thereof;
x is the absolute value of the charge of the MFy ion; and
y is 5, 6 or 7.

### Claim 2 (depends on 1)

A process according to claim 1, wherein the fluorine-containing oxidizing agent is F2, anhydrous HF, BrF5, NH4HF2, NH4F, AlF3, SbF5, ClF3, BrF3, KrF, XeF2, XeF4, NF3, or a combination thereof.

### Claim 3 (depends on 1)

A process according to claim 1, wherein the fluorine-containing oxidizing agent comprises F2.

### Claim 4 (depends on 1)

A process according to claim 1, wherein M is Si, Ge, Sn, Ti, Zr, or a combination thereof.

### Claim 5 (depends on 1)

A process according to claim 1, wherein
A is Na, K, Rb, Cs, or a combination thereof;
M is Si, Ge, Ti, or a combination thereof; and
Y is 6.

### Claim 6 (depends on 1)

A process according to claim 1, wherein the phosphor is K2SiF6:Mn4+.

### Claim 7 (depends on 1)

A process according to claim 1, additionally comprising contacting the color stable Mn4+ doped phosphor in particulate form with a saturated solution of a composition of formula II in aqueous hydrofluoric acid
A
x
⁢
MF
y
.
II

### Claim 8

A process for synthesizing a color stable Mn4+ doped phosphor, the process comprising contacting a phosphor of formula I,
A
x
⁢
MF
y
⁢
:
⁢
Mn
4
+
I
at an elevated temperature with a fluorine-containing oxidizing agent to form the color stable Mn4+ doped phosphor, the fluorine-containing oxidizing agent comprises a compound selected from the group consisting of: F2, anhydrous HF, BrF5, NH4F, AlF3, SF6, SbF5, ClF3, KrF, XeF4, NF3, PbF2, ZnF2, SiF4, SnF2, CdF2, a C1-C4 fluorocarbon and a combination thereof; and
contacting the color stable Mn4+ doped phosphor in particulate form with a saturated solution of a composition of formula II in aqueous hydrofluoric acid
A
x
⁢
MF
y
II
wherein
A is independently at each occurrence Li, Na, K, Rb, Cs, NR4 or a combination thereof;
M is independently at each occurrence Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Hf, Y, La, Nb, Ta, Bi, Gd, or a combination thereof;
R is H, lower alkyl, or a combination thereof;
x is independently at each occurrence the absolute value of the charge of the MFy ion; and
y is independently at each occurrence 5, 6 or 7.

### Claim 9 (depends on 8)

A process according to claim 8, wherein the temperature ranges from about 200° C. to about 700° C.

### Claim 10 (depends on 8)

A process according to claim 8, wherein the temperature ranges from about 350° C. to about 600° C.

### Claim 11 (depends on 8)

A process according to claim 8, wherein the phosphor is contacted with the fluorine-containing oxidizing agent for a period of at least four hours.

### Claim 12 (depends on 8)

A process according to claim 8, wherein M is Si, Ge, Sn, Ti, Zr, or a combination thereof.

### Claim 13 (depends on 8)

A process according to claim 8, wherein
A is Na, K, Rb, Cs, or a combination thereof;
M is Si, Ge, Ti, or a combination thereof; and
Y is 6.

### Claim 14 (depends on 8)

A process according to claim 8, wherein the phosphor is K2SiF6:Mn4+.

### Claim 15 (depends on 8)

A process according to claim 8, wherein the fluorine-containing oxidizing agent is a C1-C4 fluorocarbon.

### Claim 16 (depends on 15)

A process according to claim 15, wherein the fluorine-containing oxidizing agent further comprises F2.

### Claim 17 (depends on 15)

A process according to claim 15, wherein the C1-C4 fluorocarbon is selected from CF4, C2F6, C3F8, C2H2F4, C2HF3, and combinations thereof.

### Claim 18 (depends on 17)

The process according to claim 17, wherein the C1-C4 fluorocarbon is CF4.