ELECTROLUMINESCENT PHOSPHOR AND METHOD OF MAKING
A copper activated zinc sulfide electroluminescent phosphor is disclosed, wherein the phosphor comprises greater than about 1,000 ppm copper. Also disclosed is a copper activated zinc sulfide electroluminescent phosphor having a y color coordinate of at least about 0.480. A method for preparing the copper activated zinc sulfide electroluminescent phosphor is disclosed, comprising contacting a zinc sulfide, a first copper source, a magnesium source, and a lithium halide to form a first mixture; heating the mixture at a temperature and for a time sufficient to form a fired mixture; subjecting the fired mixture to a shear force capable of inducing a plurality of defects in the zinc sulfide lattice structure; and then contacting the fired mixture with a second copper source and a zinc oxide to form a second mixture; heating the second mixture at a temperature and for a time sufficient to form a second-fired material.
1 . A copper activated zinc sulfide electroluminescent phosphor comprising greater than about 1,000 ppm copper.
2 . The copper activated zinc sulfide electroluminescent phosphor of claim 1 , comprising at least about 1,100 ppm copper.
3 . The copper activated zinc sulfide electroluminescent phosphor of claim 1 , comprising at least about 1,300 ppm copper.
4 . The copper activated zinc sulfide electroluminescent phosphor of claim 1 , comprising at least about 1,600 ppm copper.
5 . The copper activated zinc sulfide electroluminescent phosphor of claim 1 , comprising a zinc sulfide lattice, and wherein all or substantially all of the copper is present within the zinc sulfide lattice.
6 . The copper activated zinc sulfide electroluminescent phosphor of claim 1 , having a y color coordinate of at least about 0.480.
7 . The copper activated zinc sulfide electroluminescent phosphor of claim 1 , having a y color coordinate of at least about 0.490.
8 . The copper activated zinc sulfide electroluminescent phosphor of claim 1 , having a y color coordinate of at least about 0.500.
9 . The copper activated zinc sulfide electroluminescent phosphor of claim 1 , having a y color coordinate of at least about 0.520.
10 . The copper activated zinc sulfide electroluminescent phosphor of claim 1 , comprising from about 1,100 ppm to about 1,600 ppm copper and having a y color coordinate of from about 0.480 to about 0.520.
11 . The copper activated zinc sulfide electroluminescent phosphor of claim 1 , having an x color coordinate of from about 0.180 to about 0.200.
12 . A method for preparing a copper activated zinc sulfide electroluminescent phosphor, the method comprising:
a) contacting a zinc sulfide, a first copper source, a magnesium source, and a lithium halide to form a first mixture;
b) heating the first mixture at a temperature and for a time sufficient to form a fired mixture;
c) subjecting the fired mixture to a shear force capable of inducing a plurality of defects in the zinc sulfide lattice structure; and then
d) contacting the fired mixture with a second copper source and a zinc oxide to form a second mixture; and then
e) heating the second mixture at a temperature and for a time sufficient to form a second-fired material.
13 . The method of claim 12 , wherein step a) comprises contacting a zinc sulfide, a first copper source, a magnesium source, a lithium halide, and at least one of a zinc oxide, sulfur, sodium chloride, barium chloride, or a combination thereof.
14 . The method of claim 12 , wherein heating the first mixture comprises heating at a temperature of at least about 1,020° C. for a period of for at least about 1 hour.
15 . The method of claim 12 , wherein heating the first mixture comprises heating at a temperature and for a time sufficient to transform at least a portion of the zinc sulfide from a cubic lattice structure to a hexagonal lattice structure.
16 . The method of claim 12 , further comprising washing at least one of the first mixture, the second mixture, or a combination thereof, to remove at least a portion of any flux and/or copper sulfide remaining on the phosphor surface.
17 . The method of claim 16 , comprising washing both the first mixture and the second mixture to remove at least a portion of any flux and/or copper sulfide remaining on the phosphor surface.
18 . The method of claim 16 , wherein washing comprises contacting the fired mixture with an acidic solution and then with a basic solution.
19 . The method of claim 12 , wherein the first copper source and the second copper source comprise the same composition.
20 . The method of claim 12 , wherein heating the second mixture comprises heating at a temperature of from about 700° C. to about 850° C. for a period of at least about 1 hour.