Red-emitting phosphors, associated processes and devices
View Patent ↗A process for synthesizing a Mn 4+ doped phosphor is presented. The process includes contacting a source of Mn 4+ ions to a suspension comprising aqueous hydrofluoric acid and a complex fluoride compound of formula (II) in solid form, and then contacting a source of A + ions to the suspension to form the Mn 4+ doped phosphor, A x [MF y ] (II) 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.
1. A population of particles having a core which is substantially free of Mn 4+ ions, a first shell and a second shell, wherein the core comprises a compound of formula (II)
A x [MF y ] (II);
the first shell comprises a composition of formula (IV)
A x [(M 1−z ,Mn z )F y ] (IV)
and the second shell comprises a composition of formula (V)
A x [(M 1−w ,Mn w )F y ] (V)
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<z≦0.2; and
0≦w≦z.
2. The population of particles according to claim 1 , comprising a particle size distribution having a particle size span ≦1.
3. The population of particles according to claim 1 , comprising a particle size distribution having a particle size span ≦0.9.
4. The population of particles according to claim 1 , wherein the core is K 2 SiF 6 and first shell is K 2 (Si 1−z , Mn z )F 6 .
5. The population of particles according to claim 1 , wherein the second shell is K 2 (Si 1−w , Mn w )F 6 .
6. A lighting apparatus comprising a semiconductor light source and the population of particles according to claim 1 radiationally coupled to the light source.
7. A backlight device comprising a semiconductor light source and the population of particles according to claim 1 radiationally coupled to the light source.