Color stable red-emitting phosphors

Abstract

A process for preparing a Mn +4 doped phosphor of formula I A x [MF y ]:Mn +4    I includes gradually adding a first solution to a second solution gradually discharging the product liquor from the reactor while volume of the product liquor in the reactor remains constant; 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. The first solution includes a source of M and HF and the second solution includes a source of Mn to a reactor in the presence of a source of A.

1 - 10 . (canceled) 
     
     
         11 . A Mn +4  doped phosphor of formula I comprising a population of particles having a particle size distribution comprising D 50  particle size ranging from about 10 μm to about 40 μm and a span less than 1.1;
   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; and 
 y is 5, 6 or 7. 
 
     
     
         12 . A Mn +4  doped phosphor according to  claim 11 , wherein the D 50  ranges from about 15 μm to about 35 μm. 
     
     
         13 . A Mn +4  doped phosphor according to  claim 11 , wherein the span is less than 1. 
     
     
         14 . A Mn +4  doped phosphor according to  claim 11 , wherein the span is less than 0.9. 
     
     
         15 . A Mn +4  doped phosphor according to  claim 11 , wherein the span is less than 0.8. 
     
     
         16 . A lighting apparatus comprising a Mn +4  doped phosphor according to  claim 11 . 
     
     
         17 . A backlight device comprising a Mn +4  doped phosphor according to  claim 11 . 
     
     
         18 - 22 . (canceled)