Phosphors with long-persistent green phosphorescence
AssigneesUniversity of Georgia Research Foundation, Inc., University of Puerto Rico
InventorsWilliam M Yen, Weiyi Jia, Lizhu Lu, Huabiao Yuan
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Abstract
This invention relates to phosphors including long-persistence green phosphors. Phosphors of the invention are represented by the general formula: MkAl2O4:2xEu2+,2yR3+ wherein k−1-2x-2y, x is a number ranging from about 0.0001 to about 0.05, y is a number ranging from about x to about 3x, M is an alkaline earth metal, and R3+ is one or more trivalent metal ions. Phosphors of this invention include powders, ceramics, single crystals and single crystal fibers. A method of manufacturing improved phosphors and a method of manufacturing single crystal phosphors are also provided.
Claims47
A phosphor represented by the formula:
- MkAl2O4:2xEU2+, 2yR3+
- wherein k=1-2x-2y, x is a number ranging from about 0.0001 to about 0.05, y is a number ranging from about 0.0001 to about 0.15, M is an alkaline earth metal, and R3+ is one or more trivalent metal ions and wherein a portion of the Al3+ in the host is substituted by a divalent ion.
A phosphor represented by the formula:
- MkAl2O4:2xEu2+, 2y1R13+, 2y2Y3+
- wherein k=1-2x-2y, y1+y2=y, x is a number ranting from about 0.0001 to about 0.05, y is a number ranging from about 0.0001 to about 0.15, M is an alkaline earth metal, and R13+ is one or more trivalent metal ions.
The phosphor represented by the formula:
- MkAl2O4:2xEu2+, 2yR3+
- wherein k=1-2x-2y, x is a number ranging from about 0.0001 to about 0.05, y is a number ranging from about 0.0001 to about 0.15, M is an alkaline earth metal, and R3+ is one or more trivalent metal ions and wherein a portion of M2+ in the phosphor is substituted by a monovalent metal ion.
The phosphor represented by the formula:
- MkAl2O4:2xEu2+, 2yR3+
- wherein k=1-2x-2y, x is a number ranging from about 0.0001 to about 0.05, y is a number ranging from about 0.0001 to about 0.15, M is an alkaline earth metal, R3+ is one or more trivalent metal ions and which is formed as a single crystal.
A method for making a single crystal phosphor which comprises the steps:
- (a) combining phosphor components according to the stoichiometric amounts of the formula:
- MkAl2O4.2xEu2+,2yR3+
- wherein k=1-2x-2y, x is a number ranging from about 0.0001 to about 0.05, y is a number ranging from about 0.0001 to about 0.15, M is an alkaline earth metal and R3+ is one or more trivalent metal ions, to form a powder;
- (b) sintering the powder in a reducing atmosphere;
- (c) quenching the sintered material to a temperature below 650° C. to obtain a phosphor material that substantially remains in the β-phase at room temperature;
- and
- (d) crystalizing single crystals from the quenched sintered phosphor of step (c) under an inert atmosphere.
A method for making a single crystal phosphor which comprises the steps of:
- (a) combining the phosphor components according to the stoichiometry of the formula:
- MkAl2O4:2xEu2+, 2yR3+
- where k=1-2x-2y, x is a number ranging from about 0.0001 to about 0.05, y is a number ranging from about 0.0001 to about 0.15, M is an alkaline earth metal and R3+ is one or more trivalent metal ions to form a powder;
- (b) sintering the powder in a reducing atmosphere;
- and
- (c) growing single crystals from the sintered powder under an inert atmosphere.
Dependencies are inferred from the claim text.