Isotopically enriched luminescent materials and methods of making same
The invention is directed to luminescent materials containing isotopically-enriched atomic elements and methods of making these luminescent materials. Individual embodiments of the invention include isotopically-enriched ZnO:Zn, ZnS:Cu:Cl, Zn 2 SiO 4 :Mn, Y 2 O 2 S:Eu, Gd 2 O 2 S:Tb and CaWO 4 phosphors as well as methods of synthesizing these luminescent materials using isotopically-enriched starting materials.
1. A luminescent compound having enhanced brightness and longevity, wherein the compound comprises an isotopically-enriched atomic element.
2. A ZnO:Zn phosphor comprising zinc isotopically-enriched in 64 Zn.
3. The ZnO:Zn phosphor of claim 2 wherein said isotopically-enriched zinc is enriched to greater than 60% 64 Zn.
4. The ZnO:Zn phosphor of claim 2 wherein said isotopically-enriched zinc is enriched to greater than 90% 64 Zn.
5. The ZnO:Zn phosphor of claim 2 wherein said isotopically-enriched zinc is enriched to greater than 96% 64 Zn.
6. A method of producing a isotopically-enriched ZnO:Zn phosphor comprising:
a. supplying ZnO with the Zn component enriched to greater than about 60% 64 Zn, in a silica crucible;
b. placing said silica crucible a larger crucible containing lampblack;
c. heating said ZnO containing crucibles in an electric furnace to about 1000° C. for about one hour; and,
d. slowly cooling said furnace to produce an isotopically-enriched ZnO:Zn phosphor.
7. A ZnS:Cu:Cl phosphor comprising isotopically-enriched zinc.
8. A ZnS:Cu:Cl phosphor comprising isotopically-enriched sulfur.
9. A ZnS:Cu:Cl phosphor comprising isotopically-enriched zinc and isotopically-enriched sulfur.
10. The ZnS:Cu:Cl phosphor of claim 7 wherein said isotopically-enriched zinc is enriched to greater than about 60% 64 Zn.
11. The ZnS:Cu:Cl phosphor of claim 7 wherein said isotopically-enriched zinc is enriched to greater than about 90% 64 Zn.
12. The ZnS:Cu:Cl phosphor of claim 7 wherein said isotopically-enriched zinc is enriched to greater than about 96% 64 Zn.
13. The ZnS:Cu:Cl phosphor of claim 8 wherein said isotopically-enriched sulfur is enriched to greater than about 93% 32 S.
14. The ZnS:Cu:Cl phosphor of claim 9 wherein said isotopically-enriched sulfur is enriched to greater than about 93% 32 S, and wherein said isotopically-enriched zinc is enriched to greater than about 60% 64 Zn.
15. The ZnS:Cu:Cl phosphor of claim 9 wherein said isotopically-enriched sulfur is enriched to greater than about 95% 32 S, and wherein said isotopically-enriched zinc is enriched to greater than about 96% 64 Zn.
16. A method of producing an isotopically-enriched ZnS:Cu:Cl phosphor comprising:
a. mixing luminescent grade ZnS, with the zinc component enriched to greater than about 60% 64 Zn with 100 ppm Cu as CuCl 2 and 2 weight percent NaCl;
b. heating said mixture under a flowing nitrogen atmosphere at about 1000° C.;
c. exposing the mixture to H 2 S gas for about 1 hour; and,
d. slowly cooling the mixture to recover a ZnS:Cu:Cl phosphor.
17. A Zn 2 SiO 4 :Mn phosphor comprising isotopically-enriched zinc.
18. A Zn 2 SiO 4 :Mn phosphor comprising isotopically-enriched silicon.
19. A Zn 2 SiO 4 :Mn phosphor comprising isotopically-enriched zinc and isotopically-enriched silicon.
20. The Zn 2 SiO 4 :Mn phosphor of claim 17 wherein said isotopically enriched zinc is enriched to greater than about 60% 64 Zn.
21. The Zn 2 SiO 4 :Mn phosphor of claim 17 wherein said isotopically enriched zinc is enriched to greater than about 90% 64 Zn.
22. The Zn 2 SiO 4 :Mn phosphor of claim 17 wherein said isotopically enriched zinc is enriched to greater than about 96% 64 Zn.
23. The Zn 2 SiO 4 :Mn phosphor of claim 18 wherein said isotopically enriched silicon is enriched to greater than about 94% 28 Si.
24. The Zn 2 SiO 4 :Mn phosphor of claim 18 wherein said isotopically enriched silicon is enriched to greater than about 99% 28 Si.
25. The Zn 2 SiO 4 :Mn phosphor of claim 18 wherein said isotopically enriched silicon is enriched to greater than about 94% 28 Si, and wherein said isotopically enriched zinc is enriched to greater than about 60% 64 Zn.
26. The Zn 2 SiO 4 :Mn phosphor of claim 19 wherein said isotopically enriched silicon is enriched to greater than about 99% 28 Si, and wherein said isotopically enriched zinc is enriched to greater than about 96% 64 Zn.
27. A method of producing an isotopically-enriched Zn 2 SiO 4 :Mn phosphor comprising:
a. heating ZnO, SiO 2 and MnO at a ratio of 2 moles: 1.01 moles: 0.012 moles, wherein the zinc in said ZnO is enriched to greater than about 60% 64 Zn, to about 1250° C. for about one hour; and,
b. cooling said mixture to produce an isotopically-enriched Zn 2 SiO 4 :Mn phosphor.
28. The method of claim 27 wherein the Si in said SiO 2 is enriched to greater than 94% 28 Si.
29. An Y 2 O 2 S:Eu phosphor comprising isotopically-enriched sulfur.
30. The Y 2 O 2 S:Eu phosphor of claim 29 wherein said isotopically enriched sulfur is enriched to greater than 97% 32 S.
31. A method of producing an isotopically-enriched Y 2 O 2 S:Eu phosphor comprising:
a. blending luminescent grade Y 2 O 3 , Eu 2 O 3 , sodium carbonate, and luminescent grade sulfur enriched to greater than about 97% 32 S under acetone;
b. firing the dried mixture at about 1000° C. for about two hours; and,
c. washing the resulting powder in hot de-ionized water to produce an isotopically-enriched Y 2 O 2 S:Eu phosphor.
32. A Gd 2 O 2 S:Tb phosphor comprising isotopically-enriched sulfur.
33. The Gd 2 O 2 S:Tb phosphor of claim 32 wherein said isotopically enriched sulfur is enriched to greater than 97% 32 S.
34. A method of producing a Gd 2 O 2 S:Tb phosphor comprising:
a. blending luminescent grade Gd 2 O 3 , Tb 4 O 7 , sodium carbonate, and luminescent grade sulfur enriched to greater than 97% 32 S under acetone;
b. firing the dried mixture at about 1000° C. for about two hours; and,
c. washing the resulting powder in hot de-ionized water to produce a Gd 2 O 2 S:Tb phosphor.
35. A CaWO 4 compound comprising isotopically-enriched calcium wherein the compound is a phosphor.
36. A CaWO 4 phosphor comprising isotopically-enriched tungsten.
37. A CaWO 4 phosphor comprising isotopically-enriched calcium and isotopically-enriched tungsten.
38. The CaWO 4 phosphor of claim 35 wherein said isotopically-enriched calcium is enriched to greater than about 98% 40 Ca.
39. The CaWO 4 phosphor of claim 36 wherein said isotopically-enriched tungsten is enriched to greater than about 50% 186 W.
40. The CaWO 4 phosphor of claim 36 wherein said isotopically-enriched tungsten is enriched to greater than about 80% 186 W.
41. The CaWO 4 phosphor of claim 36 wherein said isotopically-enriched tungsten is enriched to greater than about 90% 186 W.
42. The CaWO 4 phosphor of claim 36 wherein said isotopically-enriched tungsten is enriched to greater than about 95% 186 W.
43. The CaWO 4 phosphor of claim 36 wherein said isotopically-enriched tungsten is enriched to greater than about 99% 186 W.
44. The CaWO 4 phosphor of claim 37 wherein said isotopically-enriched tungsten is enriched to greater than about 90% 186 W, and wherein said enriched calcium is enriched to greater than about 98% 40 Ca.
45. A method of producing an isotopically-enriched CaWO 4 phosphor comprising:
a. mixing CaO, enriched to greater than about 98% 40 Ca, with WO 3 ;
b. heating the mixture to about 1100° C. for about one hour; and,
c. cooling the mixture to produce a CaWO 4 phosphor.
46. The method of claim 45 , wherein said WO 3 is enriched to greater than about 50% 186 W.