White emitting persistent phosphor
View Patent ↗This disclosure features a persistent phosphor having the following formula I: Sr a ,Ca b ,Ba c Al 2-m-n-o-p Od:Eu y ,RE z ,B m ,Zn n ,Co o ,Sc p I where a and b each range from about 0.3 to about 0.7; c is between about 0 and about 0.1; 0.75≦a+b+c+y+z≦1.3; y is between about 0.0005 and about 0.1; RE is any rare earth element alone or in combination; z is between about 0.0005 and about 0.15; m is between about 0.0005 and about 0.30; n is between about 0 and about 0.10; o is between about 0 and about 0.01; p is between about 0 and about 0.10 and d ranges from about 3.945 to about 4.075. Once the persistent phosphor has been excited it appears white in an absence of ambient light. Also featured is an article of manufacture that includes the phosphor.
1. A persistent phosphor having the following formula I:
Sr a ,Ca b ,Ba c Al 2-m-n-o-p O d :Eu y ,RE z ,B m ,Zn n ,Co o ,Sc p I
where a and b each range from about 0.3 to about 0.7; c is between 0 and about 0.1; 0.75≦a+b+c+y+z≦1.3; y is between about 0.0005 and about 0.1; RE is any rare earth element alone or in combination; z is between about 0.0005 and about 0.15; m is between about 0.0005 and about 0.30; n is between 0 and about 0.10; o is between 0 and about 0.01; p is between 0 and about 0.10 and d ranges from about 3.945 to about 4.075, wherein once said persistent phosphor has been excited said persistent phosphor appears white in an absence of ambient light.
2. The persistent phosphor of claim 1 wherein RE is one or both of Dy 3+ and Nd 3+ .
3. The persistent phosphor of claim 2 wherein RE is Dy 3+ .
4. The persistent phosphor of claim 1 wherein a and b each range from about 0.4 to about 0.6.
5. The persistent phosphor of claim 1 wherein a ranges from about 0.3 to about 0.4 and b ranges from about 0.6 to about 0.7.
6. The persistent phosphor of claim 1 wherein a ranges from about 0.4 to about 0.5 and b ranges from about 0.5 to about 0.6.
7. The persistent phosphor of claim 1 wherein a ranges from about 0.5 to about 0.6 and b ranges from about 0.4 to about 0.5.
8. The persistent phosphor of claim 1 wherein a is about 0.3 and b is about 0.7.
9. The persistent phosphor of claim 1 wherein a is about 0.4 and b is about 0.6.
10. The persistent phosphor of claim 1 wherein each of a and b is about 0.5.
11. The persistent phosphor of claim 1 , which is a single phase crystalline material as determined by X-ray diffractometry.
12. An article of manufacture comprising said persistent phosphor of claim 1 .
13. The persistent phosphor of claim 1 wherein at least one of c, n, o and p is >0.
14. The persistent phosphor of claim 1 wherein a<0.7 and b>0.3.
15. The persistent phosphor of claim 1 wherein a ranges from 0.3 to 0.6 and b ranges from 0.4 to 0.7.