Red-emitting nitride-based calcium-stablized phosphors

1. A red-emitting phosphor comprising a nitride-based composition represented by the chemical formula Ca a Sr b Si c N e Eu f , wherein:

0.1≦a≦0.4;

1.5<b<2.5;

4.0≦c≦5.0;

7.5<e<8.5; and

0<f<0.1;

wherein a+b+f>2.

2. The red-emitting phosphor of claim 1 , further comprising at least one of F, Cl, Br and O.

3. The red-emitting phosphor of claim 1 , wherein said red-emitting phosphor is selected from the group consisting of:

Eu 0.05 Ca 0.1 Sr 1.95 Si 5 N 8 ;

Eu 0.05 Ca 0.2 Sr 1.95 Si 5 N 8 ;

Eu 0.5 Ca 0.3 Sr 1.95 Si 5 N 8 ; and

Eu 0.05 Ca 0.4 Sr 1.95 Si 5 N 8 .

4. The red-emitting phosphor of claim 1 , wherein said red-emitting phosphor absorbs radiation at a wavelength ranging from about 200 nm to about 550 nm and emits light with a photoluminescence peak emission wavelength greater than 620.0 nm.

5. The red-emitting phosphor of claim 1 , wherein said red-emitting phosphor has the general crystalline structure of Sr 2 Si 5 N 8 : Eu with Ca incorporated therein.

6. The red-emitting phosphor of claim 5 , wherein Ca is located within said general crystalline structure substantially at interstitial sites.

7. The red-emitting phosphor of claim 1 , wherein said red-emitting phosphor consists of Ca, Sr, Si, N, Eu and at least one of F, Cl, Br and O.

8. The red-emitting phosphor of claim 1 , wherein 0.15≦a≦0.25.

9. A red-emitting phosphor comprising a nitride-based composition represented by the chemical formula M x M′ 2 Si 5 N 8 :A, wherein:

M is at least one of Mg, Ca, Sr, Ba, Y and Li, and x>0;

M′ is at least one of Mg, Ca, Sr, Ba, Y and Li; and

A is at least one of Eu, Ce, Tb, Pr, Sm and Mn;

wherein said red-emitting phosphor has the general crystalline structure of M′ 2 Si 5 N 8 :A, and wherein M≠M′.

10. The red-emitting phosphor of claim 9 , wherein said red-emitting phosphor absorbs radiation at a wavelength ranging from about 200 nm to about 550 nm and emits light with a photoluminescence peak emission wavelength greater than 620.0 nm.

11. The red-emitting phosphor of claim 9 , further comprising at least one of F, Cl, Br and O.

12. The red-emitting phosphor of claim 9 , wherein said red-emitting phosphor consists of Ca, Sr, Si, N, Eu and at least one of F, Cl, Br and O.

13. The red-emitting phosphor of claim 9 , wherein M′ is Sr.

14. The red-emitting phosphor of claim 9 , wherein M is Ca.

15. The red-emitting phosphor of claim 9 , wherein RE is Eu.

16. The red-emitting phosphor of claim 9 , wherein 0.1≦x≦0.4.

17. A white light emitting device comprising:

a solid state excitation source with emission wavelength within a range from 200 nm to 480 nm;

a red-emitting phosphor comprising a nitride-based composition represented by the chemical formula Ca a Sr b Si c N e Eu f , wherein:

0.1≦a≦0.4;

1.5<b<2.5;

4.0≦c≦5.0;

7.5<e<8.5; and

0<f<0.1;

wherein a+b+f>2, said red-emitting phosphor being configured to absorb excitation radiation from said excitation source and to emit light having a peak emission wavelength in the range from about 624.1 nm to about 630.16 nm; and

a yellow/green-emitting phosphor having a peak emission wavelength in the range from about 500 nm to about 580 nm.

18. The white light emitting device of claim 17 , wherein said red-emitting phosphor is selected from the group consisting of:

Eu 0.05 Ca 0.1 Sr 1.95 Si 5 N 8 ;

Eu 0.05 Ca 0.2 Sr 1.95 Si 5 N 8 ;

Eu 0.05 Ca 0.3 Sr 1.95 Si 5 N 8 , and

Eu 0.05 Ca 0.4 Sr 1.95 Si 5 N 8 .

19. The white light emitting device of claim 17 , wherein said excitation source has an emission wavelength within a range from 450 nm to 470 nm.

20. The white light emitting device of claim 17 , further comprising at least one of F, Cl, Br and O.

21. The white light emitting device of claim 17 , wherein said red-emitting phosphor consists of Ca, Sr, Si, N, Eu and at least one of F, Cl, Br and O.

22. The white light emitting device of claim 17 , wherein 0.15≦a≦0.25.

23. A red-emitting phosphor comprising a nitride-based composition represented by the chemical formula M x M′ 2 G 5-y D y E 8 : A, wherein:

M is at least one of of Li, Na, K, Sc, Mg, Ca, Sr, Ba, Zn, B and Y;

M′ is at least one of Mg, Ca, Sr, Ba and Zn;

G is at least one of C, Si and Ge, and 0≦y≦1.0;

D is at least one of B, Al, Ga, In and Tl;

E is at least one of 0, N, F, Cl, Br and I; and

A is at least one of Eu, Ce, Tb, Pr, Sm and Mn;

wherein x>y/v and v is the valence of M, and wherein said red-emitting phosphor has the general crystalline structure of M′ 2 G 5 E 8 :A.

24. The red-emitting phosphor of claim 23 , wherein said red-emitting phosphor emits light with a photoluminescence peak emission wavelength greater than about 620.0 nm when under blue light excitation.

25. The red-emitting phosphor of claim 23 , wherein D is at least one of B, Al and Ga.

26. The red-emitting phosphor of claim 23 , wherein M is Ca.

27. The red-emitting phosphor of claim 23 , wherein G is Si.

28. The red-emitting phosphor of claim 23 , wherein M is Ca and G is Si.

29. A white light emitting device comprising:

a solid state excitation source with emission wavelength within a range from 200 nm to 480 nm;

a red-emitting phosphor according to claim 23 ; and

a yellow/green-emitting phosphor having a peak emission wavelength in the range from about 500 nm to about 580 nm.

30. The white light emitting device of claim 29 , wherein M is Ca and G is Si.

31. The white light emitting device of claim 29 , wherein said solid state excitation source has an emission wavelength within a range from 450 nm to 470 nm.