Color stable red-emitting phosphors
View Patent ↗A process for synthesizing a Mn 4+ doped phosphor includes contacting a precursor of formula I, A x (M 1−z ,Mn z )F y I at an elevated temperature with a fluorine-containing oxidizing agent in gaseous form to form the Mn 4+ 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 [MF y ] ion; y is 5, 6 or 7; and 0.03≦z≦0.10.
1. A process for synthesizing a Mn 4+ doped phosphor, the process comprising contacting a precursor of formula I,
A x (M 1−z ,Mn z )F y I
at an elevated temperature with a fluorine-containing oxidizing agent in gaseous form to form the Mn 4+ 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 1, 2, or 3, and is equal to the absolute value of the charge of the [MF y ] ion;
y is 5, 6 or 7; and
0.03≦z≦0.10.
2. A process according to claim 1 , wherein 0.035≦z≦0.060.
3. A process according to claim 1 , wherein 0.035≦z≦0.0510.
4. A process according to claim 1 , wherein quantum efficiency of the phosphor is at least 8% greater than quantum efficiency of the precursor.
5. A process according to claim 1 , wherein quantum efficiency of the phosphor is at least 20% greater than quantum efficiency of the precursor.
6. A process according to claim 1 , wherein A is K, M is Si, x is 2, y is 6, and 0.03≦z≦0.10.
7. A process according to claim 1 , wherein the temperature is any temperature in a range from about 500° C. to about 600° C.
8. A process according to claim 1 , wherein the fluorine-containing oxidizing agent is F 2 .
9. A process for preparing a Mn 4+ doped phosphor, the process comprising contacting a precursor at an elevated temperature with a fluorine-containing oxidizing agent in gaseous form, wherein the precursor is selected from the group consisting of
(A) A 2 [MF 5 ]:Mn 4+ , where A is selected from Li, Na, K, Rb, Cs, and combinations thereof; and
where M is selected from Al, Ga, In, and combinations thereof;
(B) A 3 [MF 6 ]:Mn 4+ , where A is selected from Li, Na, K, Rb, Cs, and combinations thereof; and
where M is selected from Al, Ga, In, and combinations thereof;
(C) Zn 2 [MF 7 ]:Mn 4+ , where M is selected from Al, Ga, In, and combinations thereof;
(D) A[In 2 F 7 ]:Mn 4+ where A is selected from Li, Na, K, Rb, Cs, and combinations thereof;
(E) A 2 [MF 6 ]:Mn 4+ , where A is selected from Li, Na, K, Rb, Cs, and combinations thereof; and
where M is selected from Ge, Si, Sn, Ti, Zr, and combinations thereof;
(F) E[MF 6 ]:Mn 4+ , where E is selected from Mg, Ca, Sr, Ba, Zn, and combinations thereof; and
where M is selected from Ge, Si, Sn, Ti, Zr, and combinations thereof;
(G) Ba 0.65 Zr 0.35 F 2.70 :Mn 4+ ; and
(H) A 3 [ZrF 7 ]:Mn 4+ where A is selected from Li, Na, K, Rb, Cs, and combinations thereof; and
the amount of manganese ranges from about 3.0 mol % to about 10 mol %.
10. A process according to claim 9 , wherein the amount of manganese ranges from about 3.5 mol % to about 6.0 mol %.
11. A process according to claim 9 , wherein the amount of manganese ranges from about 3.5 mol % to about 5.1 mol %.
12. A process according to claim 9 , wherein the amount of manganese ranges from about 3.5 mol % to about 8.0 mol %.
13. A process according to claim 9 , wherein quantum efficiency of the phosphor is at least 8% greater than quantum efficiency of the precursor.
14. A process according to claim 9 , wherein quantum efficiency of the phosphor is at least 20% greater than quantum efficiency of the precursor.