Processes for preparing color stable red-emitting phosphor particles having small particle size
A process for preparing a Mn +4 doped phosphor of formula I A x [MF y ]:Mn +4 I includes combining a first solution comprising a source of A and a second solution comprising H 2 MF 6 in the presence of a source of Mn, 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, 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 value of a Hammett acidity function of the first solution is at least −0.9. Particles produced by the process may have a particle size distribution with a D 50 particle size of less than 10 μm.
1 . A Mn +4 doped phosphor of formula I
A
x
[
MF
y
]
:
Mn
+
4
I
the phosphor comprising a monodisperse population of particles having a particle size distribution comprising a D50 particle size of less than about 10 μm;
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 an absolute value of a charge of the [MF y ] ion;
y is 5, 6 or 7; and
wherein the phosphor has a quantum efficiency of greater than 85% under blue excitation.
2 . The Mn +4 doped phosphor according to claim 1 , wherein the phosphor has an aspect ratio of a plurality of particles of the monodisperse population of less than or equal to 3/1.
3 . The Mn +4 doped phosphor according to claim 1 , wherein the phosphor has an amount of manganese from about 1.2 mol % to about 21 mol %.
4 . The Mn +4 doped phosphor according to claim 1 , wherein a span of the particle size distribution is less than 1.1.
5 . The Mn +4 doped phosphor according to claim 1 , wherein the phosphor is coated with a manganese-free shell.
6 . The Mn +4 doped phosphor according to claim 5 , wherein the manganese-free shell comprises a metal fluoride.
7 . The Mn +4 doped phosphor according to claim 5 , wherein the manganese-free shell is disposed on the phosphor.
8 . The Mn +4 doped phosphor according to claim 6 , wherein the metal fluoride is KMgF 3 .
9 . The Mn +4 doped phosphor according to claim 1 , wherein M is Si and A is Na or K.
10 . The Mn +4 doped phosphor according to claim 1 , wherein the phosphor comprises a D50 particle size from 5 μm to 8 μm.
11 . A Mn +4 doped phosphor of formula I
A
x
[
MF
y
]
:
Mn
+
4
I
the phosphor comprising a monodisperse population of particles having a particle size distribution comprising a D50 particle size of less than about 10 μm,
wherein the phosphor is coated with a manganese-free shell,
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 an absolute value of a charge of the [MF y ] ion;
y is 5, 6 or 7.
12 . The Mn +4 doped phosphor according to claim 11 , wherein the manganese-free shell comprises a metal fluoride.
13 . The Mn +4 doped phosphor according to claim 12 , wherein the metal fluoride is KMgF 3 .
14 . The Mn +4 doped phosphor according to claim 11 , wherein the phosphor has an aspect ratio of a plurality of particles of the monodisperse population of less than or equal to 3/1.
15 . The Mn +4 doped phosphor according to claim 11 , wherein the phosphor has an amount of manganese from about 1.2 mol % to about 21 mol %.
16 . The Mn +4 doped phosphor according to claim 11 , wherein a span of the particle size distribution is less than 1.1.
17 . The Mn +4 doped phosphor according to claim 11 , wherein the manganese-free shell is disposed on the phosphor.
18 . The Mn +4 doped phosphor according to claim 11 , wherein M is Si and A is Na or K.
19 . The Mn +4 doped phosphor according to claim 11 , wherein the phosphor has a quantum efficiency of greater than 85% under blue excitation.
20 . The Mn +4 doped phosphor according to claim 11 , wherein the phosphor comprises a D50 particle size from 5 μm to 8 μm.
21 . A phosphor composition comprising the Mn +4 doped phosphor according to claim 1 and further comprising one or more materials selected from the group consisting of other phosphors, quantum dot materials, scattering particles, electroluminescent polymers and dyes.
22 . The phosphor composition according to claim 21 , wherein the Mn +4 doped phosphor has an aspect ratio of a plurality of particles of the monodisperse population of less than or equal to 3/1.
23 . The phosphor composition according to claim 21 , wherein the M n+4 doped phosphor has an amount of manganese from about 1.2 mol % to about 21 mol %.
24 . The phosphor composition according to claim 21 , wherein a span of the particle size distribution is less than 1.1.
25 . The phosphor composition according to claim 21 , wherein the Mn +4 doped phosphor is coated with a manganese-free shell.
26 . The phosphor composition according to claim 25 , wherein the manganese-free shell comprises a metal fluoride.
27 . The phosphor composition according to claim 25 , wherein the manganese-free shell is disposed on the Mn +4 doped phosphor.
28 . The phosphor composition according to claim 26 , wherein the metal fluoride is KMgF 3 .
29 . The phosphor composition according to claim 21 , wherein M is Si and A is Na or K.
30 . The phosphor composition according to claim 21 , wherein the Mn +4 doped phosphor has a quantum efficiency of greater than 85% under blue excitation.
31 . The phosphor composition according to claim 21 , wherein the other phosphors comprise β-SiAlON or a yellow phosphor.
32 . The phosphor composition according to claim 21 , wherein the one or more materials comprises quantum dots.
33 . A silicone slurry composition comprising an Mn +4 doped phosphor of formula I suspended in the slurry,
A
x
[
MF
y
]
:
Mn
+
4
I
the phosphor comprising a monodisperse population of particles having a particle size distribution comprising a D50 particle size of less than about 10 μm;
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 an absolute value of a charge of the [MF y ] ion;
y is 5, 6 or 7; and
wherein the Mn +4 doped phosphor has an aspect ratio of a plurality of particles of the monodisperse population of less than or equal to 3/1.
34 . The silicone slurry composition according to claim 33 , wherein the Mn +4 doped phosphor has an amount of manganese from about 1.2 mol % to about 21 mol %.
35 . A silicone slurry composition comprising an Mn +4 doped phosphor of formula I suspended in the slurry,
A
x
[
MF
y
]
:
Mn
+
4
I
the phosphor comprising a monodisperse population of particles having a particle size distribution comprising a D50 particle size of less than about 10 μm;
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 an absolute value of a charge of the [MF y ] ion;
y is 5, 6 or 7; and
wherein a span of the particle size distribution is less than 1.1.
36 . The silicone slurry composition according to claim 33 , wherein the Mn +4 doped phosphor comprises a manganese-free shell.
37 . The silicone slurry composition according to claim 36 , wherein the manganese-free shell comprises a metal fluoride.
38 . The silicone slurry composition according to claim 36 , wherein the manganese-free shell is disposed on the phosphor.
39 . A silicone slurry composition comprising an Mn +4 doped phosphor of formula I suspended in the slurry,
A
x
[
MF
y
]
:
Mn
+
4
I
the phosphor comprising a monodisperse population of particles having a particle size distribution comprising a D50 particle size of less than about 10 μm;
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 an absolute value of a charge of the [MF y ] ion;
y is 5, 6 or 7; and
wherein the Mn +4 doped phosphor comprises a manganese-free shell comprising a metal fluoride of KMgF 3 .
40 . The silicone slurry composition according to claim 33 , wherein M is Si and A is Na or K.
41 . The silicone slurry composition according to claim 33 , wherein the Mn +4 doped phosphor has a quantum efficiency of greater than 85% under blue excitation.
42 . The silicone slurry composition according to claim 33 further comprising one or more materials selected from the group consisting of other phosphors, quantum dot materials, scattering particles, electroluminescent polymers and dyes.
43 . The silicone slurry composition according to claim 42 , wherein the other phosphors comprise β-SiAlON or a yellow phosphor.
44 . The silicone slurry composition according to claim 42 , wherein the one or more materials comprises quantum dots.
45 . A microemulsion composition comprising a Mn +4 doped phosphor of formula I
A
x
[
MF
y
]
:
Mn
+
4
I
the phosphor comprising a monodisperse population of particles having a particle size distribution comprising a D50 particle size of less than about 10 μm;
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 an absolute value of a charge of the [MF y ] ion;
y is 5, 6 or 7.
46 . The microemulsion composition according to claim 45 further comprising a surfactant.
47 . The microemulsion composition according to claim 45 , wherein the phosphor has an amount of manganese from about 1.2 mol % to about 21 mol %.
48 . The microemulsion composition according to claim 45 , wherein the Mn +4 doped phosphor has an aspect ratio of a plurality of particles of the monodisperse population of less than or equal to 3/1.
49 . The microemulsion composition according to claim 45 , wherein a span of the particle size distribution is less than 1.1.
50 . The microemulsion composition according to claim 45 , wherein M is Si and A is Na or K.
51 . A structure comprising the phosphor composition of claim 21 , wherein the structure comprises one or more layers.
52 . The structure according to claim 51 , wherein the structure has a single layer.
53 . The structure according to claim 51 , wherein the structure is multi-layered and each layer comprises at least one of the Mn +4 doped phosphor, other phosphors or quantum dot material.