Persistent phosphors of alkaline earths modified by halides and 3d ions

• US 20120256126A1
• Filed: 04/07/2011
• Published: 10/11/2012
• Est. Priority Date: 04/07/2011
• Status: Active Grant

• Current Assignee: Performance Indicator, LLC
• Original Assignee: Performance Indicator, LLC
• Inventors: Jia, Weiyi
• Granted Patent: US 8,932,486 B2
• Time in Patent Office: Days
• US Class Current: 252/301.4H
• CPC Class Codes: C09K 11/77922 Silicates

Abstract

Phosphorescent compositions including silicate of alkaline earth materials which are modified by at least one halide are provided. The phosphorescent compositions may include 3d ions. A variety of embodiments may be realized. The appearance of some embodiments may be glassy (i.e., vitreous).

Claims

1. A phosphorescent silicate-halide composition, according to the general formula:

(n−

x)MO.xM′

X₂.(1−

k)MgO.kMgX₂. 2SiO₂;

yEu,zR,wD

where

M is at least one of Sr, Ca, and Ba;

M′

is at least one of Sr, Ca and Ba;

X is at least one of F and Cl;

R is at least one of Dy³⁺, Nd³⁺, and optionally comprises at least one rare earth selected from the group of ions comprising La, Ce, Pr, Sm, Gd, Tb, Ho, Er, Tm, Yb, Y and Lu;

D is at least one 3d ion selected from the group comprising Ti, V, Cr, Mn, Fe, Co, Ni, Cu;

n ranges from 0.9 to 3.2;

x ranges from 0.0001 to 0.7;

k ranges from 0.0001 to 1.0;

y ranges from 0.0001 to 0.1;

z ranges from 0.0001 to 0.1; and

w ranges from 0.0001 to 0.02.

2. The composition of claim 1, where:

n=2, M=Sr, M′

=Ba, X═

F and Cl, x=0.0001 to 0.7, k=0, y=0.0001 to 0.1, and z=0.0001 to 0.1, R=Dy³⁺ or Nd³⁺, Er³⁺, Tm³⁺, Ho³⁺, or a combination thereof, and w=0.001 to 0.02.

3. The composition of claim 1, where:

n=1, M=Sr, M′

=at least one of Sr, Ca, Ba, X═

F or Cl, x=0.0001 to 0.7, y=0.0001 to 0.1, z=0.0001 to 0.1, R=at least one of Dy³⁺, Nd³⁺ and optionally Er, Tm, Ho, or other rare earth materials, and w=0.001 to 0.02.

4. The composition of claim 1, wherein an emission wavelength of the composition is centered about a wavelength that is within a range of about 455 nm to about 490 nm.

5. The composition of claim 1, wherein an absorption wavelength of the composition is centered about a wavelength that is within a range of about 400 nm to about 450 nm.

6. A method for fabricating a glassy phosphorescent silicate-halide composition, the method comprising:

mixing a composition according to the general formulae;

(n−

x)MO.xM′

X₂.(1−

k)MgO.kMgX₂. 2SiO₂;

yEu,zR,wD

where

M is at least one of Sr, Ca, and Ba;

M′

is at least one of Sr, Ca and Ba;

X is at least one of F and Cl;

R is at least one of Dy³⁺, Nd³⁺, and optionally comprises at least one rare earth selected from the group of ions comprising La, Ce, Pr, Sm, Gd, Tb, Ho, Er, Tm, Y, Yb, and Lu;

D is at least one 3d ion selected from the group comprising Ti, V, Cr, Mn, Fe, Co, Ni, Cu;

n ranges from 0.9 to 3.2;

x ranges from 0.0001 to 0.7;

k ranges from 0.0001 to 1.0;

y ranges from 0.0001 to 0.1;

z ranges from 0.0001 to 0.1;

w ranges from 0.0001 to 0.02;

sintering the mixture at a temperature from about 850 degrees Celsius to about 1,400 degrees Celsius; and

finishing the composition at a temperature that is elevated about 50 degrees Celsius to about 100 degrees Celsius above the sintering temperature.

7. The method as in claim 6, further comprising performing the sintering in a slightly reducing flow of hydrogenated nitrogen gas.

8. The method as in claim 6, wherein the melting temperature is between about 850 degrees Celsius and 1,300 degrees Celsius.

9. The method as in claim 6, wherein the finished composition comprises one of:

Sr₂MgSi₂O₇;

Eu,Dy;

BaF₂;

Sr₂MgSi₂O₇;

Eu,Dy;

MgF₂; and

, SrMgSi₂O₆;

Eu,Dy;

BaF₂.