COLOR STABLE RED-EMITTING PHOSPHORS

1 . A lighting apparatus comprising a semiconductor light source in direct contact with a polymer composite comprising a color stable Mn 4+ doped phosphor, wherein the lighting apparatus has a color shift of ≦2 MacAdam ellipses after operating for 30 minutes at a LED current density greater than 70 A/cm 2 , a LED wall-plug efficiency greater than 18%, and a board temperature greater than 25° C.

2 . A lighting apparatus according to claim 1 , wherein the color stable Mn 4+ doped phosphor is of formula 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.

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

4 . A lighting apparatus 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.

5 . A lighting apparatus according to claim 1 , wherein the color stable Mn 4+ doped phosphor is K 2 SiF 6 :Mn 4+ .

6 . A color stable Mn 4+ doped phosphor of formula I,

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

wherein % intensity loss of the phosphor after exposure to light flux of at least 80 w/cm 2 at a temperature of at least 50° C. for at least 21 hours is ≦4%.

7 . A color stable Mn 4+ doped phosphor according to claim 6 , wherein the % intensity loss of the phosphor is ≦3%.

8 . A color stable Mn 4+ doped phosphor according to claim 6 , wherein the % intensity loss of the phosphor is ≦1.5%.

9 . A color stable Mn 4+ doped phosphor according to claim 6 , of formula K 2 SiF 6 :Mn 4+ .