IR emitting pyroxene phosphors and light emitting device using the same

1. A luminescent material comprising E 1-w Sc 1-x-y-u-w M y Z u A 2w Si 2-z-u Ge z Al u :Cr x , wherein:

E comprises one or more of Li, Na, and K;

M comprises one or more of Al, Ga, In, Tm, Yb, and Lu;

Z comprises one or more of Ti, Zr, and Hf;

A comprises one or more of Mg, Zn, and Ni;

0<x≤0.25;

0≤y≤0.75;

0≤z≤2;

0≤u≤1;

0≤w≤1;

1+y+u+w>0; and

z+u≤2.

2. The luminescent material according to claim 1 , wherein:

E at least comprises Li;

M at least comprises Lu and/or A at least comprises Mg; when A comprises Mg,

0.1≤w≤0.4;

0.01≤x≤0.1;

0≤y≤0.2; and

0≤z≤0.5.

3. The luminescent material according to claim 1 , wherein 0≤z≤0.05.

4. The luminescent material according to claim 1 , wherein Z at least comprises Zr.

5. The luminescent material according to claim 1 , wherein 0≤u≤0.25.

6. The luminescent material according to claim 1 , wherein 0.02≤y≤0.2.

7. The luminescent material according to claim 1 , wherein 0≤w≤0.5.

8. The luminescent material according to claim 1 , comprising one or more of LiSc 1-x-y Lu y Si 2 O 6 :Cr x , LiSc 1-x-y (Lu,Al)Si 2 O 6 :Cr x , and Li 1-w Sc 1-x-w Mg 2w Si 2 O 6 :Cr x .

9. A luminescent material composition comprising (a) the luminescent material according to claim 1 and (b) a second luminescent material; wherein the luminescent material is excitable with first light, wherein the luminescent material is configured to provide first luminescence upon irradiation with the first light, wherein the second luminescent material is configured to provide second luminescence upon irradiation with the first light, wherein the luminescent material and the second luminescent material are configured to provide first and second luminescence in one or more of the red and infrared wavelength ranges, and wherein the first and second luminescence have different centroid wavelengths (λ 1 ,λ b 2 ).

10. The luminescent material composition according to claim 9 , wherein the second luminescent material comprises one or more of:

RE 3 Ga 5-x-y A x SiO 14 :Cr y (RE=La, Nd, Gd, Yb, Tm; A=Al, Sc), wherein 0≤x≤1 and 0.005≤y≤0.1;

Gd 3-x RE x Sc 2-y-z Ln y Ga 3-w Al w O 12 :Cr z (Ln=Lu, Y, Yb, Tm; RE=La, Nd, Lu), wherein 0≤x≤3; 0≤y≤1.5; 0≤z≤0.3; and 0≤w≤2;

AAEM 1-x F 6 :Cr x (A=Li, Cu; AE=Sr, Ca; M=Al, Ga, Sc), wherein 0.005<x≤0.2;

A 2-x (WO 4 ) 3 :Cr x (A=Al, Ga, Sc, Lu, Yb), wherein 0.003≤x≤0.5;

Sc 1-x-y A y MO:Cr x , wherein MO=BO 3 , or MO=P 3 O 9 , or MO=(BP 3 O 12 ) 0.5 , or MO=(SiP 5 O 19 ) 0.34 , with A=Lu, In, Yb, Tm, Y, Ga, Al, wherein 0<x≤0.75, 0≤y≤1;

M 2-x Si 5-y Al y O y N 8-y :Eu x (M=Ba, Sr, Ca), wherein 0<x≤0.05, 0≤y≤0.1;

M 1-x SiAlN 3 :Eu x (M=Sr, Ca), wherein 0<x≤0.03; and

M 1-x LiAl 3 N 4 :Eu x (M=Ba, Sr, Ca), wherein 0<x≤0.02.

11. The luminescent material composition according to claim 9 , wherein the second luminescent material comprises Gd 3-x RE x Sc 2-y-z Ln y Ga 3-w Al w O 12 :Cr z (Ln=Lu, Y, Yb, Tm; RE=La, Nd, Lu), wherein 0≤x≤3; 0≤y≤1.5; 0<z≤0.3; and 0≤w≤2.

12. A device comprising:

a first light source configured to generate first light; and

the luminescent material as defined in claim 1 , wherein the luminescent material is configured to convert at least part of the first light into first luminescence.

13. The device according to claim 12 , comprising:

a second luminescent material configured to provide second luminescence upon irradiation with the first light, wherein the luminescent material and the second luminescent material are configured to provide first and second luminescence in one or more of the red and infrared wavelength ranges, and wherein the first and second luminescence have different centroid wavelengths (λ 1 ,λ 2 ); and

optionally a second light source configured to generate second light;

wherein the second luminescent material is configured to convert one or more of (a) part of the second light and (b) at least part of the optional second light into second luminescence.

14. The device according to claim 12 , wherein:

the luminescent material comprises one or more of LiSc 1-x-y Lu y Si 2 O 6 :Cr x , LiSc 1-x-y (Lu,Al) y Si 2 O 6 :Cr x , and Li 1-w Sc 1-x-w Mg 2w Si 2 O 6 :Cr x ; and

a second luminescent material configured to provide second luminescence upon irradiation with the first light, wherein the luminescent material and the second luminescent material are configured to provide first and second luminescence in one or more of the red and infrared wavelength ranges, and wherein the first and second luminescence have different centroid wavelengths (λ 1 ,λ 2 ), the second luminescent material comprising Gd 3-x RE x Sc 2-y-z Ln y Ga 3-w Al w O 12 :Cr z (Ln=Lu, Y, Yb, Tm; RE=La, Nd, Lu), wherein 0≤x≤3; 0≤y≤1.5; 0<z≤0.3; and 0≤w≤2.

15. The device according to claim 12 , further comprising an optical sensor configured to detect radiation in one or more of the red and infrared wavelength ranges.

16. A luminescent material comprising Li 1-w Sc 1-x-w Mg 2w Si 2 O 6 :Cr x , wherein 0<x≤0.25; 0≤w≤1; and x+w≤1.

17. The luminescent material according to claim 16 , wherein 0≤w≤0.5.

18. A luminescent material composition comprising (a) the luminescent material according to claim 16 and (b) a second luminescent material; wherein the luminescent material is excitable with first light, wherein the luminescent material is configured to provide first luminescence upon irradiation with the first light, wherein the second luminescent material is configured to provide second luminescence upon irradiation with the first light, wherein the luminescent material and the second luminescent material are configured to provide first and second luminescence in one or more of the red and infrared wavelength ranges, and wherein the first and second luminescence have different centroid wavelengths Gd 3-x RE x Sc 2-y-z Ln y Ga 3-w Al w O 12 :Cr z (λ 1 ,λ 2 ).

19. The luminescent material composition according to claim 18 , wherein the second luminescent material comprises (Ln=Lu, Y, Yb, Tm; RE=La, Nd, Lu), wherein 0≤x≤3; 0≤y≤1.5; 0≤z≤0.3; and 0≤w≤2.

20. A device comprising:

a first light source configured to generate first light; and

the luminescent material as defined in claim 16 , wherein the luminescent material is configured to convert at least part of the first light into first luminescence.