Long persistent phosphors and persistent energy transfer technique
AssigneeUniversity of Georgia Research Foundation, Inc.
InventorsWilliam M. Yen, Dongdong Jia, Weiyi Jia, Xiao-Jun Wang
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Abstract
The invention provides long-persistent phosphors, methods for their manufacture and phosphorescent articles. The invention also provides a method for generating a long-persistent phosphorescence at a selected color. The phosphors of the invention may be alkaline earth aluminates, alkaline earth silicates, and alkaline earth aluminosilicates. The phosphors include those activated by cerium. The phosphors also include those in which persistent energy transfer occurs from a donor ion to an acceptor ion, producing persistent emission largely characteristic of the acceptor ion.
Claims42
A method for generating long persistent phosphorescence at a selected color comprising the steps of:
- a) selecting at least a first activator capable of producing long persistent phosphorescence of a first color when incorporated with optional co-activators into a host;
- b) selecting at least a second activator capable of producing long persistent phosphorescence of the selected color when incorporated into the host with the first activator and the optional co-activators, the second activator being capable of accepting optical energy from the first activator;
- c) fabricating a long-persistent phosphor comprising the second activator, the first activator and optional co-activators incorporated into the host;
- and
- d) irradiating the long-persistent phosphor, thereby producing long-persistent phosphorescence of the selected color,
- wherein the first activator, the second activator, and the optional co-activators are all different ions and the first color is different from the selected color.
A method for making a long persistent phosphor comprising the steps of:
- a) combining the phosphor components according to the stoichiometry of the formula:
- v(MO)·(x/2)(Al2O3).y(SiO2):dD, cC, aA
- where M is an alkaline-earth metal, D is a donor ion, C is a co activator ion, A is an acceptor ion, v>0, x≧0, y≧0, x+y>0, 0<d≦10%, 0≦c≦10% and 0<a≦10% and;
- and
- b) sintering the phosphor components in a reducing atmosphere.
A long persistent phosphor comprising a host, a donor ion, optional co-activators, and an acceptor ion, wherein the donor ion is capable of transfer of optical energy to the acceptor ion, the phosphor emits light largely characteristic of the acceptor ion and the first activator, the second activator, and the optional co-activators are all different ions.
A long persistent phosphor represented by the formula:
- MvAlxSiyOz:
- dD, cC, aA
- wherein M is an alkaline earth metal, D is a donor ion, A is an acceptor ion, C is a co activator ion v>0, x≧0, y≧0, x+y>0, z>0, 0<d≦10%, 0≦c≦10% and 0<a≦10% and the phosphor emits light largely characteristic of the acceptor ion.
A long persistent phosphor represented by the formula
- MvAlxSiyOz:
- nCe3l
- wherein M is an alkaline earth metal v>0, x≧0, y≧0, x+y>0, z>0, and n is between about 0.1% and 5%.
A long persistent phosphor represented by the formula:
- MSiO3:
- dEu2+, cDy3+, aMn2+
- where M is an alkaline earth metal.
Dependencies are inferred from the claim text.