Near infrared doped phosphors having an alkaline gallate matrix
View Patent ↗Phosphors based on doping of an activator (an emitter) into a host matrix are disclosed herein. Such phosphors include alkaline gallate phosphors doped with Cr 3+ or Ni 2+ ions, which in some embodiments can exhibit persistent infrared phosphorescence for as long as 200 hours. Such phosphors can be used, for example, as components of a luminescent paint.
1. A phosphor comprising a material having one or more of the following formulas:
AGa 5 O 8 :x C, y R;and
AGaO 2 :x C, y R
wherein a portion of Ga may optionally be replaced with a Group IIIA metal and/or a Group IVA metal; and
wherein each A is independently an alkaline metal;
each C is independently Cr 3+ , Ni 2+ , or a combination thereof;
each R is independently a Zn 2+ ion, an alkaline earth metal ion, or a combination thereof;
each x is independently 0.01 to 5 and represents mol % based on the total moles of Ga and any replacements thereof; and
each y is independently 0.1 to 2 and represents mol % based on the total moles of Ga and any replacements thereof.
2. The phosphor of claim 1 wherein each A is independently selected from the group consisting of Li, Na, K, and combinations thereof.
3. The phosphor of claim 1 wherein each x is independently 0.05 to 0.5 and represents mol % based on the total moles of Ga and any replacements thereof.
4. The phosphor of claim 1 wherein each R is independently selected from the group consisting of Mg 2+ , Ca 2+ , Sr 2+ , Ba 2+ , Zn 2+ , and combinations thereof.
5. The phosphor of claim 1 wherein each C is Cr 3+ .
6. The phosphor of claim 5 having emission band peaks at 690 to 1100 nm.
7. The phosphor of claim 1 wherein each C is Ni 2+ .
8. The phosphor of claim 7 having emission band peaks at 1100 to 1550 nm.
9. A phosphor comprising a material having one or more of the following formulas:
AGa 5 O 8 :x C, y R;and
AGaO 2 :x C, y R
wherein a portion of Ga may optionally be replaced with a Group IIIA metal and/or a Group IVA metal; and
wherein each A is independently an alkaline metal;
wherein each C is a combination of Cr 3+ and Ni 2+ ;
each R is independently a Zn 2+ ion, an alkaline earth metal ion, or a combination thereof;
each x is independently 0.01 to 5 and represents mol % based on the total moles of Ga and any replacements thereof; and
each y is independently 0 to 5 and represents mol % based on the total moles of Ga and any replacements thereof.
10. The phosphor of claim 9 having emission band peaks at 690 to 1100 nm and 1100 to 1550 nm.
11. The phosphor of claim 1 wherein a portion of Ga is substituted with a Group IIIA metal.
12. The phosphor of claim 11 wherein the Group IIIA metal is selected from the group consisting of B, Al, In, and combinations thereof.
13. A phosphor comprising a material having one or more of the following formulas:
AGa 5 O 8 :x C, y R;and
AGaO 2 :x C, y R
wherein a portion of Ga is substituted with a Group IVA metal; and
wherein each A is independently an alkaline metal;
each C is independently Cr 3+ , Ni 2+ , or a combination thereof;
each R is independently a Zn 2+ ion, an alkaline earth metal ion, or a combination thereof;
each x is independently 0.01 to 5 and represents mol % based on the total moles of Ga and any replacements thereof; and
each y is independently 0 to 5 and represents mol % based on the total moles of Ga and any replacements thereof.
14. The phosphor of claim 13 wherein the Group IVA metal is selected from the group consisting of Ge, Si, Sn, and combinations thereof.
15. The phosphor of claim 1 wherein an emission persists for up to 200 hours after excitation.
16. The phosphor of claim 1 wherein the phosphor is chemically stable in one or more of air, tap water, salt water, seawater, bleach water, and bleach-salt-sodium bicarbonate (NaHCO 3 ) aqueous solution.
17. A luminescent paint comprising a phosphor comprising a material having one or more of the following formulas:
AGa 5 O 8 :x C, y R;and
AGaO 2 :x C, y R
wherein a portion of Ga may optionally be replaced with a Group IIIA metal and/or a Group IVA metal; and
wherein each A is independently an alkaline metal;
each C is independently Cr 3+ , Ni 2+ , or a combination thereof;
each R is independently a Zn 2+ ion, an alkaline earth metal ion, or a combination thereof;
each x is independently 0.01 to 5 and represents mol % based on the total moles of Ga and any replacements thereof; and
each y is independently 0 to 5 and represents mol % based on the total moles of Ga and any replacements thereof.
18. A method of activating a phosphor comprising:
providing a phosphor according to claim 1 ; and
exposing the phosphor to one or more of solar radiation, an ultraviolet lamp, a fluorescent lamp, and a light emitting diode (LED) light.
19. An activated phosphor comprising a phosphor according to claim 1 that has been exposed to one or more of solar radiation, an ultraviolet lamp, a fluorescent lamp, and a light emitting diode (LED) light, and wherein the activated phosphor has an emission that persists for up to 200 hours after excitation.