FLUORESCENT MATERIAL, A MANUFACTURING METHOD THEREOF, AND A PHOTO-LUMINESCENT COMPOSITION CONTAINING THE FLUORESCENT MATERIAL

Abstract

A fluorescent material comprises a compound having the general formula of:

[Lu.sub.1−a−c−d−2/3bY.sub.aΣ(Ln−1).sub.cΣ(Ln−2).sub.dM.sub.b].sub.3±δ[Al.sub.1−xGa.sub.x].sub.5(O.sub.1−1/2yX.sub.y).sub.12±1.5δ.

The fluorescent material is combined with other compounds to form a photo-luminescent composition. The fluorescent material and the composition containing the same have a lot of advantages, such as high brightness, high color rendering index, high stability, and low light decay.

Claims

1. A fluorescent material comprising a compound having a general formula I:
[Lu.sub.1−a−c−d−2/3bY.sub.aΣ(Ln−1).sub.cΣ(Ln−2).sub.dM.sub.b].sub.3±δ[Al.sub.1−xGa.sub.x].sub.5(O.sub.1−1/2yX.sub.y).sub.12±1.5δ   (I) in which: M is at least one element selected from the group consisting of Ca, Mg, Ba, Sr, and Zn; (1−a−c−d−2/3b+a+c+d)(3±δ)≠3, 0≦b≦0.2; 0.001≦a≦0.95; 0≦x≦0.5; Σ(Ln−1) represents at least one element of La, Gd, Tb, Nd, Ho, and 0≦c≦0.9; Σ(Ln−2) represents an activator and is at least one element selected from the group consisting of Ce, Pr, Dy, Eu, Tm, Er, Sm, Yb, and Sc, and 0.001≦d≦0.5; X represents a co-activator, which is at least one element selected from F and Cl, and 0.001≦y≦0.2; 1−a−c−d≧0; and 0<δ≦1.5.

2. The fluorescent material according to claim 1, wherein said fluorescent material comprises a compound having a general formula I-1:
[Lu.sub.1−a−c−d−2/3bY.sub.aΣ(Ln−1).sub.cΣ(Ln−2).sub.dM.sub.b].sub.3−δ[Al.sub.1−xGa.sub.x].sub.5(O.sub.1−1/2yX.sub.y).sub.12−1.5δ   (I-1) in which Σ(Ln−2) represents at least one element of Ce and Pr.

3. The fluorescent material according to claim 1, wherein said fluorescent material comprising a compound having a general formula I-2:
[Lu.sub.1−a−c−d−2/3bY.sub.aΣ(Ln−1).sub.cΣ(Ln−2).sub.dM.sub.b].sub.3+δ[Al.sub.1−xGa.sub.x].sub.5(O.sub.1−1/2yX.sub.y).sub.12+1.5δ   (I-2) in which 0≦b<0.2.

4. The fluorescent material according to claim 1, wherein said fluorescent material is selected from the group consisting of following compounds:
[Lu.sub.0.4415Y.sub.0.45Ce.sub.0.05Ba.sub.0.0585].sub.2.8Al.sub.5(O.sub.0.9957,F.sub.0.01).sub.11.7;
[Y.sub.0.7623Gd.sub.0.17Ce.sub.0.05Ba.sub.0.01774].sub.2.884Al.sub.5(O.sub.0.9985,F.sub.0.003).sub.11.826;
[Y.sub.0.6323Gd.sub.0.29Ce.sub.0.06Ba.sub.0.01774].sub.2.884Al.sub.5(O.sub.0.9985,F.sub.0.003).sub.11.826;
[Y.sub.0.3823Gd.sub.0.55Ce.sub.0.05Ba.sub.0.01774].sub.2.884Al.sub.5(O.sub.0.9985,F.sub.0.003).sub.11.826;
[Lu.sub.0.0995Y.sub.0.7688Gd.sub.0.07Nd.sub.0.0005Ce.sub.0.05Ba.sub.0.01125].sub.2.5(Al.sub.4.9Ga.sub.0.1)(O.sub.0.9997,F.sub.0.002).sub.11.25; and
[Lu.sub.0.0995Y.sub.0.77Gd.sub.0.07Nd.sub.0.0005Ce.sub.0.05Ba.sub.0.01].sub.1.67(Al.sub.4.9Ga.sub.0.1)(O.sub.0.999,F.sub.0.002).sub.10.005.

5. The fluorescent material according to claim 1, wherein said fluorescent material is selected from the group consisting of following compounds:
[Y.sub.0.8829Gd.sub.0.005Ce.sub.0.05Ba.sub.0.0621].sub.3.28Al.sub.5(O.sub.0.9957,F.sub.0.01).sub.12.42;
[Lu.sub.0.4812Y.sub.0.45Ce.sub.0.05Ba.sub.0.0188].sub.3.35A1.sub.5(O.sub.0.9985,F.sub.0.003).sub.12.525;
[Lu.sub.0.5812Y.sub.0.35Ce.sub.0.05Ba.sub.0.0188].sub.3.35A1.sub.5(O.sub.0.9985,F.sub.0.003).sub.12.525;
[Lu.sub.0.7312Y.sub.0.2Ce.sub.0.05Ba.sub.0.0188].sub.3.35Al.sub.5(O.sub.0.99857,F.sub.0.003).sub.12.525;
[Y.sub.0.9262Ce.sub.0.055Ba.sub.0.0188].sub.3.35Al.sub.4.5Ga.sub.0.5(O.sub.0.99857,F.sub.0.003).sub.12.525;
[Y.sub.0.9262Ce.sub.0.055Ba.sub.0.0188].sub.3.35Al.sub.4.0Ga.sub.1.0(O.sub.0.99857,F.sub.0.003).sub.12.525;
[Y.sub.0.9262Ce.sub.0.055Ba.sub.0.0188].sub.3.35Al.sub.3.5Ga.sub.1.5(O.sub.0.9985,F.sub.0.003).sub.12.525;
[Y.sub.0.9262Ce.sub.0.055Ba.sub.0.0188].sub.3.35Al.sub.3.0Ga.sub.2.0(O.sub.0.9985,F.sub.0.003).sub.12.525; and
[Y.sub.0.9262Ce.sub.0.055Ba.sub.0.0188].sub.3.35Al.sub.2.79Ga.sub.2.21(O.sub.0.99857,F.sub.0.003).sub.12.525.

6. A method for preparing the fluorescent material according to claims 1 to 5, comprising: mixing yttrium oxide, cerium oxide, aluminium oxide or aluminium hydroxide, gadolinium oxide, gallium oxide, lutetium oxide, neodymium oxide, aluminum fluoride, barium fluoride uniformly to form a mixture, in which the amounts of yttrium oxide, cerium oxide, aluminium oxide or aluminium hydroxide, gadolinium oxide, gallium oxide, lutetium oxide, neodymium oxide are weighed according to the molar ratios of the metal elements of the phosphor according to any one of claims 1 to 5, while aluminium oxide or aluminium hydroxide is added in an amount in excess of 2 percent by weight, barium fluoride is in an amount of from 2 to 4.5 percent by weight of all oxides, and aluminum fluoride is in an amount of less than 1 percent; and roasting the mixture at a temperature of 1330° C. to 1580° C. under a reducing atmosphere of a nitrogen-hydrogen mixed gas or a carbon reducing atmosphere for 5 to 7 hours.

7. The method according to claim 6, wherein said roasting is undertaken at a temperature of 1426° C. for 5 hours under a carbon reducing atmosphere.

8. A photo-luminescent composition comprising: fluorescent material according to claim 1, and a red-emitting phosphor; wherein the weight ratio of the fluorescent material and the red-emitting phosphor powder is from about 88%:12% to 92%:8%.

9. The photo-luminescent composition according to claim 8, wherein the weight ratio of the fluorescent material and the red-emitting phosphor is about 90%:10%.

10. The photo-luminescent composition according to claim 8, wherein said red-emitting phosphor is selected from the group consisting of nitrides and silicates.

11. The photo-luminescent composition according to claim 10, wherein the red-emitting phosphor is a nitride having a general formula of SrAlSiN.sub.3:Eu.sup.2+.

12. The photo-luminescent composition according to claim 10, wherein the red-emitting phosphor is a silicate having a general formula of (Sr,Ba).sub.1.88SiO.sub.4:Eu.sup.2+.

13. The photo-luminescent composition according to claim 11, wherein said fluorescent material is [Lu.sub.0.4415Y.sub.0.45Ce.sub.0.05Ba.sub.0.0585].sub.2.8Al.sub.5(O.sub.0.995,F.sub.0.01).sub.11.7.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0086] FIG. 1A and FIG. 1B show XRD spectra, respectively, of the Y.sub.3Al.sub.5O.sub.12 standard powder diffraction card and the fluorescent material having a formula: [Y.sub.0.7623Gd.sub.0.17Ce.sub.0.05Ba.sub.0.01774].sub.2.884Al.sub.5(O.sub.0.9985,F.sub.0.003).sub.11.826.

[0087] FIG. 2 shows the excitation and emission spectra of the fluorescent material having a formula [Lu.sub.0.4415Y.sub.0.45Ce.sub.0.05Ba.sub.0.0585].sub.2.8Al.sub.5(O.sub.0.995,F.sub.0.01).sub.11.7 and silicate-based green phosphor powder with a formula YSrBaSiO.sub.5:Eu.sup.2+, respectively, under monitoring of 555 nm and excitation of 460 nm blue LED.

[0088] FIG. 3 shows the emission spectrum of the fluorescent material having a formula [Y.sub.0.8829Gd.sub.0.005Ce.sub.0.05Ba.sub.0.0621].sub.3.28Al.sub.5(O.sub.0.995,F.sub.0.01).sub.12.42 excited at 460 nm blue LED.

[0089] FIG. 4 shows the emission spectra of fluorescent materials with different ratios of Y to Lu excited by 460 nm blue LED. The molecular formulas of the fluorescent materials are, respectively:

[Lu.sub.0.4812Y.sub.0.45Ce.sub.0.05Ba.sub.0.0188].sub.3.35Al.sub.5(O.sub.0.9985,F.sub.0.003).sub.12.5257

[Lu.sub.0.5812Y.sub.0.35Ce.sub.0.05Ba.sub.0.0188].sub.3.35Al.sub.5(O.sub.0.9985,F.sub.0.003).sub.12.525, and

[Lu.sub.0.7312Y.sub.0.2Ce.sub.0.05Ba.sub.0.0188].sub.3.35Al.sub.5(O.sub.0.9985,F.sub.0.003).sub.12.525.

[0090] FIG. 5 shows the excitation spectra of fluorescent materials with different ratios of Y to Gd at 564 nm, 572 nm, and 578 nm, respectively;

[0091] FIG. 6 shows the emission spectra of fluorescent materials with different ratios of Y to Gd excited by 460 nm blue LED. The molecular formulas of the fluorescent materials are, respectively:

[Y.sub.0.7623Gd.sub.0.17Ce.sub.0.05Ba.sub.0.01774].sub.2.884Al.sub.5(O.sub.0.9985,F.sub.0.003).sub.11.8267

[Y.sub.0.6323Gd.sub.0.29Ce.sub.0.06Ba.sub.0.01774].sub.2.884Al.sub.5(O.sub.0.9985,F.sub.0.003).sub.11.826, and

[Y.sub.0.3823Gd.sub.0.55Ce.sub.0.05Ba.sub.0.01774].sub.2.884Al.sub.5(O.sub.0.9985,F.sub.0.003).sub.11.826.

[0092] FIG. 7 shows the emission spectra of fluorescent materials with different ratios of (3−δ) excited by 460 nm blue LED. The molecular formulas of the fluorescent materials are, respectively:

[Lu.sub.0.0995Y.sub.0.7688Gd.sub.0.07Nd.sub.0.0005Ce.sub.0.05Ba.sub.0.01125].sub.2.5(Al.sub.4.9Ga.sub.0.1)(O.sub.0.999,F.sub.0.002).sub.11.257

[Lu.sub.0.0995Y.sub.0.77Gd.sub.0.07Nd.sub.0.0005Ce.sub.0.05Ba.sub.0.01].sub.1.67(Al.sub.4.9Ga.sub.0.1)(O.sub.0.999,F.sub.0.002).sub.10.005.

[0093] FIG. 8 shows the emission spectra of fluorescent materials with different ratios of Al to Ga excited by 460 nm blue LED. The molecular formulas of the fluorescent materials are, respectively:

[Y.sub.0.9262Ce.sub.0.055Ba.sub.0.0188].sub.3.35Al.sub.4.5Ga.sub.0.5(O.sub.0.9985,F.sub.0.003).sub.12.525,

[Y.sub.0.9262Ce.sub.0.055Ba.sub.0.0188].sub.3.35Al.sub.4.0Ga.sub.1.0(O.sub.0.9985,F.sub.0.003).sub.12.525,

[Y.sub.0.9262Ce.sub.0.055Ba.sub.0.0188].sub.3.35Al.sub.3.5Ga.sub.1.5(O.sub.0.9985,F.sub.0.003).sub.12.525,

[Y.sub.0.9262Ce.sub.0.055Ba.sub.0.0188].sub.3.35Al.sub.3.0Ga.sub.2.0(O.sub.0.9985,F.sub.0.003).sub.12.525, and

[Y.sub.0.9262Ce.sub.0.055Ba.sub.0.0188].sub.3.35Al.sub.2.79Ga.sub.2.21(O.sub.0.9985,F.sub.0.003).sub.12.525.

[0094] FIG. 9 shows the spectra for white LED photo-luminescent compositions tested on a blue light diode-based solid white light source, and the compositions are formed by the fluorescent material having the formula (Lu.sub.0.4415Y.sub.0.45Ce.sub.0.05Ba.sub.0.0585).sub.2.8Al.sub.5(O.sub.0.995,F.sub.0.01).sub.11.7 with a red-emitting phosphor powder SrAlSiN.sub.3:Eu.sup.2+ and (Sr,Ba).sub.1.88SiO.sub.4:Eu.sup.2+, and by Y.sub.3Al.sub.5O.sub.12:Ce.sup.3+ and SrAlSiN.sub.3:Eu.sup.2+, respectively.

DETAILED DESCRIPTION OF THE INVENTION

[0095] The phosphor powder prepared has the molecular formula:

[Lu.sub.1−a−c−d−2/3bY.sub.aΣ(Ln−1).sub.cΣ(Ln−2).sub.dM.sub.b].sub.3−δ[Al.sub.1-xGa.sub.x].sub.5(O.sub.1−1/2yX.sub.y).sub.12−1.5δ

[Lu.sub.1−a−c−d−2/3bY.sub.aΣ(Ln−1).sub.cΣ(Ln−2).sub.dM.sub.b].sub.3+δ[Al.sub.1−xGa.sub.x].sub.5(O.sub.1−1/2yX.sub.y).sub.12+1.5δ

[0096] According to the difference between the stoichiometric index (3±δ) and (12±1.5δ), 15 samples are synthesized using different ratios of rare earth elements and doped aluminum.

[0097] As specific examples, data is provided for 15 samples, and the optical properties thereof exhibit a regular change.

[0098] The phosphor powder samples shown in the embodiment are prepared by roasting the mixture of Y.sub.2O.sub.3, rare-earth metals oxides, and Al.sub.2O.sub.3 at a high temperature. And the particle size (D50) of the starting material used is less than 3 microns (measured by a laser particle size analyzer).

PREPARATION EXAMPLES

[0099] There are many ways to synthesize aluminate as a green-emitting phosphor powder, such as high temperature solid phase method, co-precipitation method, sol-gel method, etc.

[0100] In the present invention, a fluorescent material is prepared by a high temperature solid phase method.

Required Raw Materials:

[0101] (a) Y.sub.2O.sub.3—(5N) [0102] (b) Gd.sub.2O.sub.3—(4N) [0103] (c) Al.sub.2O.sub.3—(4N) [0104] (d) CeO.sub.2—(4N) [0105] (e) Ga.sub.2O.sub.3—(4N) [0106] (f) Lu.sub.2O.sub.3—(4N) [0107] (g) Nd.sub.2O.sub.3—(4N) [0108] (h) AlF.sub.3—(4N) [0109] (i) BaF.sub.2—(4N)

[0110] Raw materials (yttrium oxide, lanthanide rare earth metal oxides and alumina) dry powder are vibrated and mixed evenly in sealed plastic containers.

[0111] The mixture is added with a compound containing a co-activator halogen element and capable of acting as a fluxing agent (e.g., barium fluoride and aluminum fluoride) during the calcination preparation. Its role as a fluxing agent is to form a liquid phase in the solid surface reaction, thereby speeding up the mass transfer rate and the generation speed of the target product. The doping amount of barium fluoride is 2% to 4.5% by weight of the oxide, and the doping amount of the aluminum fluoride is less than 1%.

[0112] After the materials above are ground well, they are loaded into a high purity alumina (Al.sub.2O.sub.3) crucible, gradually heated in a hydrogen-hydrogen reduction (V.sub.N2/V.sub.H2=3/1) atmosphere or a carbon reducing atmosphere, and roasted at a temperature of 1330° C. to 1580° C. for from 5 to 7 hours and then removed from the furnace when cooled to below 500° C.

[0113] Pickling with concentrated nitric acid, then washing with potassium pyrophosphate, washing with water several times to neutral, adding 0.1% lanthanum nitrate, neutralizing with ammonia, filtering, drying in an oven at 140° C. for several hours, washing with isopropyl alcohol, adding 5‰ ethyl orthosilicate, and coating the surface of the powder with a layer of silicon film, results in the production of loose smooth powder, i.e., the fluorescent material of the present invention.

[0114] The fluorescent materials obtained by the above method are excited by 460 nm blue light, and the emission peak is located at 537 nm to 578 nm green band.

Example 1

[0115] Proportional amounts of the starting materials are used to meet the stoichiometric requirements of the formula:

[Lu.sub.0.4415Y.sub.0.45Ce.sub.0.05Ba.sub.0.0585].sub.2.8Al.sub.5(O.sub.0.995,F.sub.0.01).sub.11.7.

The starting materials Y.sub.2O.sub.3, Lu.sub.2O.sub.3, CeO.sub.2, Al.sub.2O.sub.3, AlF.sub.3, and BaF.sub.2 are roasted under a nitrogen-hydrogen reducing atmosphere (V.sub.N2/V.sub.H2=3/1) at a temperature of 1337° C. for 5 hours.

[0116] The excitation (under the monitoring of 555 nm) and emission (under excitation of 460 nm blue LED) spectra of this fluorescent material having a molecular formula:

[Lu.sub.0.4415Y.sub.0.45Ce.sub.0.05Ba.sub.0.0585].sub.2.8Al.sub.5(O.sub.0.9957,F.sub.0.01).sub.11.7

are shown in FIG. 2.

Example 2

[0117] Proportional amounts of the starting materials are used to meet the stoichiometric requirements of the formula:

[Y.sub.0.8829Gd.sub.0.005Ce.sub.0.05Ba.sub.0.0621].sub.3.28Al.sub.5(O.sub.0.995,F.sub.0.01).sub.12.42.

[0118] The starting materials Y.sub.2O.sub.3, Gd.sub.2O.sub.3, CeO.sub.2, Al.sub.2O.sub.3, AlF.sub.3 and BaF.sub.2 are roasted under a carbon reducing atmosphere at a temperature of 1377° C. for 7 hours.

[0119] The emission (under excitation of 460 nm blue LED) spectrum of this fluorescent material having a molecular formula:

[Y.sub.0.8829Gd.sub.0.005Ce.sub.0.05Ba.sub.0.0621].sub.3.28Al.sub.5(O.sub.0.995,F.sub.0.01).sub.12.42

is shown in FIG. 3.

Example 3

[0120] Preparation of fluorescent materials having different ratios of Y to Lu: Proportional amounts of the starting materials are used to meet the stoichiometric requirements of the respective formulas:

[Lu.sub.0.4812Y.sub.0.45Ce.sub.0.05Ba.sub.0.0188].sub.3.35Al.sub.5(O.sub.0.9985,F.sub.0.003).sub.12.5257

[Lu.sub.0.5812Y.sub.0.35Ce.sub.0.05Ba.sub.0.0188].sub.3.35Al.sub.5(O.sub.0.9985,F.sub.0.003).sub.12.525, and

[Lu.sub.0.7312Y.sub.0.2Ce.sub.0.05Ba.sub.0.0188].sub.3.35Al.sub.5(O.sub.0.99857,F.sub.0.003).sub.12.525.

The starting materials Y.sub.2O.sub.3,Lu.sub.2O.sub.3,CeO.sub.2,Al.sub.2O.sub.3,AlF.sub.3 and BaF.sub.2 are roasted under a nitrogen-hydrogen reducing atmosphere (V.sub.N2/V.sub.H2=3/1) at a temperature of 1512° C. for 5 hours.

[0121] The molecular formulas of the fluorescent materials with different ratios of Y to Lu are, respectively:

[Lu.sub.0.4812Y.sub.0.45Ce.sub.0.05Ba.sub.0.0188].sub.3.35Al.sub.5(O.sub.0.9985,F.sub.0.003).sub.12.5257

[Lu.sub.0.5812Y.sub.0.35Ce.sub.0.05Ba.sub.0.0188].sub.3.35Al.sub.5(O.sub.0.9985,F.sub.0.003).sub.12.525, and

[Lu.sub.0.7312Y.sub.0.2Ce.sub.0.05Ba.sub.0.0188].sub.3.35AlO.sub.0.9985,F.sub.0.003).sub.12.525.

The emission spectrum (under excitation of 460 nm blue LED) of the above fluorescent materials is shown in FIG. 4.

Example 4

[0122] Preparation of fluorescent materials having different ratios of Y to Gd: Proportional amounts of the starting materials are used to meet the stoichiometric requirements of the respective formulas:

[Y.sub.0.7623Gd.sub.0.17Ce.sub.0.05Ba.sub.0.01774].sub.2.884Al.sub.5(O.sub.0.9985,F.sub.0.003).sub.11.8267

[Y.sub.0.6323Gd.sub.0.29Ce.sub.0.06Ba.sub.0.01774].sub.2.884Al.sub.5(O.sub.0.9985,F.sub.0.003).sub.11.826, and

[Y.sub.0.3823Gd.sub.0.55Ce.sub.0.05Ba.sub.0.01774].sub.2.884Al.sub.5(O.sub.0.9985,F.sub.0.003).sub.11.826

The starting materials Y.sub.2O.sub.3,Gd.sub.2O.sub.3,CeO.sub.2,Al.sub.2O.sub.3,AlF.sub.3 and BaF.sub.2 are roasted under a carbon reducing atmosphere at a temperature of 1377° C. for 7 hours.

[0123] The molecular formulas of the fluorescent materials with different ratios of Y to Lu are, respectively:

[Y.sub.0.7623Gd.sub.0.17Ce.sub.0.05Ba.sub.0.01774].sub.2.884Al.sub.5(O.sub.0.9985,F.sub.0.003).sub.11.826,

[Y.sub.0.6323Gd.sub.0.29Ce.sub.0.06Ba.sub.0.01774].sub.2.884Al.sub.5(O.sub.0.9985,F.sub.0.003).sub.11.826, and

[Y.sub.0.3823Gd.sub.0.55Ce.sub.0.05Ba.sub.0.01774].sub.2.884Al.sub.5(O.sub.0.9985,F.sub.0.003).sub.11.826.

The excitation spectrum (under monitoring of 564 nm, 572 nm and 578 nm, respectively) of the above fluorescent materials is shown in FIG. 5. The emission spectrum (under excitation of 460 nm blue LED) is shown in FIG. 6.

Example 5

[0124] Proportional amounts of the starting materials are used to meet the stoichiometric requirements of the formula:

[Lu.sub.0.0995Y.sub.0.7688Gd.sub.0.07Nd.sub.0.0005Ce.sub.0.05Ba.sub.0.01125].sub.2.5(Al.sub.4.9Ga.sub.0.1)(O.sub.0.999,F.sub.0.002).sub.11.25

The starting materials Y.sub.2O.sub.3, Lu.sub.2O.sub.3,Gd.sub.2O.sub.3,CeO.sub.2,Nd.sub.2O.sub.3,Al.sub.2O.sub.3,Ga.sub.2O.sub.3,AlF.sub.3 and BaF.sub.2, are roasted under a nitrogen-hydrogen reducing atmosphere (V.sub.N2/V.sub.H2=3/1) at a temperature of 1550° C. for 5 hours.

Example 6

[0125] Proportional amounts of the starting materials are used to meet the stoichiometric requirements of the formula:

[Lu.sub.0.0995Y.sub.0.77Gd.sub.0.07Nd.sub.0.0005Ce.sub.0.05Ba.sub.0.01].sub.1.67(Al.sub.4.9Ga.sub.0.1)(O.sub.0.999,F.sub.0.002).sub.10.005.

The starting materials and thermal conditions are the same with example 5.

[0126] The emission spectrum (under excitation of 460 nm blue LED) of the fluorescent materials having different ratios of (3−δ) is shown in FIG. 7. The molecular formulas are, respectively:

[Lu.sub.0.0995Y.sub.0.7688Gd.sub.0.07Nd.sub.0.0005Ce.sub.0.05Ba.sub.0.01125].sub.2.5(Al.sub.4.9Ga.sub.0.1)(O.sub.0.999,F.sub.0.002).sub.11.25,

[Lu.sub.0.0995Y.sub.0.77Gd.sub.0.07Nd.sub.0.0005Ce.sub.0.05Ba.sub.0.01].sub.1.67(Al.sub.4.9Ga.sub.0.1)(O.sub.0.999,F.sub.0.002).sub.10.005.

Example 7

[0127] Preparation of fluorescent materials having different ratios of Al to Ga: Proportional amounts of the starting materials are used to meet the stoichiometric requirements of the respective formulas:

[Y.sub.0.9262Ce.sub.0.055Ba.sub.0.0188].sub.3.35Al.sub.4.5Ga.sub.0.5(O.sub.0.9985,F.sub.0.003).sub.12.525,

[Y.sub.0.9262Ce.sub.0.055Ba.sub.0.0188].sub.3.35Al.sub.4.0Ga.sub.1.0(O.sub.0.9985,F.sub.0.003).sub.12.525,

[Y.sub.0.9262Ce.sub.0.055Ba.sub.0.0188].sub.3.35Al.sub.3.5Ga.sub.1.5(O.sub.0.9985,F.sub.0.003).sub.12.525,

[Y.sub.0.9262Ce.sub.0.055Ba.sub.0.0188].sub.3.35Al.sub.3.0Ga.sub.2.0(O.sub.0.9985,F.sub.0.003).sub.12.525, and

[Y.sub.0.9262Ce.sub.0.055Ba.sub.0.0188].sub.3.35Al.sub.2.79Ga.sub.2.21(O.sub.0.9985,F.sub.0.003).sub.12.525.

The starting materials Y.sub.2O.sub.3, CeO.sub.2, Al.sub.2O.sub.3, Ga.sub.2O.sub.3, AlF.sub.3, and BaF.sub.2 are roasted under a carbon reducing atmosphere at a temperature of 1426° C. for 5 hours.

[0128] The molecular formulas of the fluorescent materials with different ratios of Al to Ga are, respectively:

[Y.sub.0.9262Ce.sub.0.055Ba.sub.0.0188].sub.3.35Al.sub.4.5Ga.sub.0.5(O.sub.0.9985,F.sub.0.003).sub.12.525,

[Y.sub.0.9262Ce.sub.0.055Ba.sub.0.0188].sub.3.35Al.sub.4.0Ga.sub.1.0(O.sub.0.9985,F.sub.0.003).sub.12.525,

[Y.sub.0.9262Ce.sub.0.055Ba.sub.0.0188].sub.3.35Al.sub.3.5Ga.sub.1.5(O.sub.0.9985,F.sub.0.003).sub.12.525,

[Y.sub.0.9262Ce.sub.0.055Ba.sub.0.0188].sub.3.35Al.sub.3.0Ga.sub.2.0(O.sub.0.9985,F.sub.0.003).sub.12.525, and

[Y.sub.0.9262Ce.sub.0.055Ba.sub.0.0188].sub.3.35Al.sub.2.79Ga.sub.2.21(O.sub.0.9985,F.sub.0.003).sub.12.525.

[0129] The emission spectrum (under excitation of 460 nm blue LED) of the above fluorescent materials is shown in FIG. 8.

Example 8

[0130] A white LED photo-luminescent composition is prepared by the combination of fluorescent material [Lu.sub.0.4415Y.sub.0.45Ce.sub.0.05Ba.sub.0.0585].sub.2.8Al.sub.5(O.sub.0.995, F.sub.0.01).sub.11.7 prepared in example 1 and nitride red-emitting phosphor powder SrAlSiN.sub.3:Eu.sup.2+.

Example 9

[0131] A white LED photo-luminescent composition is prepared by combination of the fluorescent material [Lu.sub.0.4415Y.sub.0.45Ce.sub.0.05Ba.sub.0.0585].sub.2.8Al.sub.5(O.sub.0.995,F.sub.0.01).sub.11.7 prepared in example 1 and the silicate red-emitting phosphor powder (Sr,Ba).sub.1.88SiO.sub.4:Eu.sup.2+.

Example 10

[0132] A white LED photo-luminescent composition is prepared by combination of fluorescent material Y.sub.3Al.sub.5O.sub.12:Ce.sup.3+ and nitride red-emitting phosphor powder SrAlSiN.sub.3:Eu.sup.2+.

[0133] The photo-luminescent composition formed by the fluorescent material prepared in example 1 with the formula [Lu.sub.0.4415Y.sub.0.45Ce.sub.0.05Ba.sub.0.0585].sub.2.8Al.sub.5(O.sub.0.995,F.sub.0.01).sub.11.7 respectively is combined with the red-emitting phosphor powder with a formula SrAlSiN.sub.3:Eu.sup.2+ or (Sr,Ba).sub.1.88SiO.sub.4:Eu.sup.2+, as well as the white LED photo-luminescent composition formed by Y.sub.3Al.sub.5O.sub.12:Ce.sup.3+ in combination with SrAlSiN.sub.3:Eu.sup.2+, which are tested in a blue light diode-based solid white light source and the spectra thereof are shown in FIG. 9.

[0134] Optical property parameters of the samples in the examples are measured, using a HAAS-2000 spectroradiometer, available from Everfine Photo-E-Info Co., Ltd. The yellow-orange fluorescence spectra reflected by samples and radiated by the composite blue light (455 nm) diode are measured, with the angle of reflection of 45° and the wavelength range from 380 nm to 780 nm. The optical characteristics of the fluorescent materials of Examples 1 to 7 are shown in Table 1 below, wherein the sample numbers correspond to the example numbers:

TABLE-US-00001 TABLE 1 I, Peak Main Colour Color Nos. of Integrated wavelength wavelength Coordinates temperature samples 3 ± δ brightness (λpeak, nm) (λdom, nm) x y (Tc, K) 1 2.8 (a = 0.45) 103.99 556 569.8 0.4352 0.5414 3856 2 3.28 (a = 0.8829) 110.36 546 568.6 0.4270 0.5489 4002 3 3.35 (a = 0.45) 107.9 543 565 0.4001 0.5603 4432 3.35 (a = 0.35) 114.69 539 564.1 0.3935 0.5627 4539 3.35 (a = 0.2) 113.09 537 561.4 0.3747 0.5676 4838 4 2.884 (a = 0.7623) 93.46 564 574.7 0.4721 0.5155 3231 2.884 (a = 0.6323) 87.16 572 577.2 0.4896 0.5014 2934 2.884 (a = 0.3823) 80.35 578 579 0.5030 0.4902 2714 5 2.5 (a = 0.7688) 95.83 562 573 0.4596 0.525 3444 6 1.67 (a = 0.77) 77.83 555 571.1 0.445 0.5348 3689 7 3.35 (x = 0.5) 101.66 549 568.9 0.429 0.5451 3959 3.35 (x = 1.0) 106.42 540 564.4 0.3951 0.5592 4505 3.35 (x = 1.5) 111.46 535 562.4 0.3816 0.5672 4730 3.35 (x = 2.0) 111.58 531 560.5 0.3685 0.5662 4932 3.35 (x = 2.21) 102.22 526 558.4 0.3551 0.5651 5149

[0135] FIG. 1A and FIG. 1B show XRD spectra, respectively, of the Y.sub.3Al.sub.5O.sub.12 standard powder diffraction card and the fluorescent material represented by the formula [Y.sub.0.7623Gd.sub.0.17Ce.sub.0.05Ba.sub.0.01774].sub.2.884Al.sub.5(O.sub.0.9985,F.sub.0.003).sub.11.826. It shows that main diffraction peaks of FIG. 1B are basically in agreement with Y.sub.3Al.sub.5O.sub.12 standard powder diffraction card (PDF#09-0310) (FIG. 1A) except for a few disordered peaks.

[0136] FIG. 2 shows the excitation and emission spectra for the fluorescent materials having a formula [Lu.sub.0.4415Y.sub.0.45Ce.sub.0.05Ba.sub.0.0585].sub.2.8Al.sub.5(O.sub.0.995,F.sub.0.01).sub.11.7 and silicate-based green-emitting phosphor powder with a formula YSrBaSiO.sub.5:Eu.sup.2+, respectively, under monitoring of 555 nm and excitation of 460 nm blue LED. It can be seen from the figure that the emission spectrum of the aluminate phosphor powder (e.g., the fluorescent material of the present invention [Lu.sub.0.4415Y.sub.0.45Ce.sub.0.05Ba.sub.0.0585].sub.2.8Al.sub.5(O.sub.0.995,F.sub.0.01).sub.11.7) covers a width of 520 nm to 610 nm and the emission peak is located near 556 nm, which is wider than the coverage of the silicate emission spectrum and the intensity is higher

[0137] FIG. 3 shows the emission spectrum of the fluorescent material having a formula [Y.sub.0.8829Gd.sub.0.005Ce.sub.0.05Ba.sub.0.0621].sub.3.28Al.sub.5(O.sub.0.995,F.sub.0.01).sub.12.42 excited at 460 nm blue LED. It can be seen from the figure that the emission spectrum covers a broadband from 520 nm to 610 nm and the emission peak is located at 546 nm.

[0138] FIG. 4 shows the effect of the variable ratios of Y to Lu on the emission spectra of phosphor powder, and the tested fluorescent materials having the following formulas respectively:

[Lu.sub.0.4812Y.sub.0.45Ce.sub.0.05Ba.sub.0.0188].sub.3.35Al.sub.5(O.sub.0.9985,F.sub.0.003).sub.12.525,

[Lu.sub.0.5812Y.sub.0.35Ce.sub.0.05Ba.sub.0.0188].sub.3.35Al.sub.5(O.sub.0.9985,F.sub.0.003).sub.12.525, and

[Lu.sub.0.7312Y.sub.0.2Ce.sub.0.05Ba.sub.0.0188].sub.3.35Al.sub.5(O.sub.0.9985,F.sub.0.003).sub.12.525.

[0139] It can be seen from the figure that the spectrum covers a broadband from 520 nm to 610 nm, moreover, with the decrease of the ratio of Y to Lu, the emission peaks blue shift and positions thereof are located at about 543 nm, 539 nm and 537 nm, respectively.

[0140] FIGS. 5 and 6 show the effect of the variable ratio of Y to Gd on excitation and emission spectra of phosphor powder and the tested fluorescent materials have the following formulas, respectively:

[Y.sub.0.7623Gd.sub.0.17Ce.sub.0.05Ba.sub.0.01774].sub.2.884Al.sub.5(O.sub.0.9985,F.sub.0.003).sub.11.826,

[Y.sub.0.6323Gd.sub.0.29Ce.sub.0.06Ba.sub.0.01774].sub.2.884Al.sub.5(O.sub.0.9985,F.sub.0.003).sub.11.826, and

[Y.sub.0.3823Gd.sub.0.55Ce.sub.0.05Ba.sub.0.01774].sub.2.884Al.sub.5(O.sub.0.9985,F.sub.0.003).sub.11.826.

[0141] As shown in FIG. 6, the spectrum covers a broadband from 520 to 610 nm, moreover, with the decrease of the ratio of Y to Gd, the emission peaks red shift and the positions thereof are located at 564 nm, 572 nm and 578 nm, respectively.

[0142] FIG. 7 shows the effect of the variable value of (3−δ) on the emission spectra of phosphor powder, and the tested fluorescent materials having the following formulas, respectively:

[Lu.sub.0.0995Y.sub.0.7688Gd.sub.0.07Nd.sub.0.0005Ce.sub.0.05Ba.sub.0.01125].sub.2.5(Al.sub.4.9Ga.sub.0.1)(O.sub.0.999,F.sub.0.002).sub.11.25

[Lu.sub.0.0995Y.sub.0.77Gd.sub.0.07Nd.sub.0.0005Ce.sub.0.05Ba.sub.0.01].sub.1.67(Al.sub.4.9Ga.sub.0.1)(O.sub.0.999,F.sub.0.002).sub.10.005.

It can be seen from the figure that the emission peaks blue shift with the decrease of the ratio of (3−δ), and the positions thereof are located at 562 nm and 555 nm, respectively.

[0143] FIG. 8 shows the effect of the variable ratio of Al to Ga on the emission spectra of phosphor powder, and the tested fluorescent materials having the following formulas, respectively:

[Y.sub.0.9262Ce.sub.0.055Ba.sub.0.0188].sub.3.35Al.sub.4.5Ga.sub.0.5(O.sub.0.9985,F.sub.0.003).sub.12.525,

[Y.sub.0.9262Ce.sub.0.055Ba.sub.0.0188].sub.3.35Al.sub.4.0Ga.sub.1.0(O.sub.0.9985,F.sub.0.003).sub.12.525,

[Y.sub.0.9262Ce.sub.0.055Ba.sub.0.0188].sub.3.35Al.sub.3.5Ga.sub.1.5(O.sub.0.9985,F.sub.0.003).sub.12.525,

[Y.sub.0.9262Ce.sub.0.055Ba.sub.0.0188].sub.3.35Al.sub.3.0Ga.sub.2.0(O.sub.0.9985,F.sub.0.003).sub.12.525, and

[Y.sub.0.9262Ce.sub.0.055Ba.sub.0.0188].sub.3.35Al.sub.2.79Ga.sub.2.21(O.sub.0.9985,F.sub.0.003).sub.12.525.

It can be seen from the figure that the emission peaks blue shift with the decrease of the ratio of Al to Ga, and the positions thereof are located at 549 nm, 540 nm, 535 nm, and 555 nm, respectively.

[0144] FIG. 9 shows the spectra for white LED photo-luminescent compositions, and the compositions are formed by the fluorescent material of the present invention having the formula (Lu.sub.0.4415Y.sub.0.45Ce.sub.0.05Ba.sub.0.0585).sub.2.8Al.sub.5 (O.sub.0.995,F.sub.0.01).sub.11.7 with a red-emitting phosphor powder SrAlSiN.sub.3:Eu.sup.2+ and (Sr,Ba).sub.1.88SiO.sub.4:Eu.sup.2+, as well as by Y.sub.3Al.sub.5O.sub.12:Ce.sup.3+ and SrAlSiN.sub.3:Eu.sup.2+, respectively. The synthesized samples are tested in a blue light diode-based solid white light source, and the results show that the color rendering index (Ra) of the white LED formed by the invention and the nitride phosphor powder reaches 86.9, the corresponding color temperature (Tc) is 3495K, the coverage of the formed spectrum is border and the effect is better.

[0145] Thus, the results above indicated that, as varying the ratio of the stoichiometric index (3±δ) from 1.0 to 3.35, the optical characteristics of the samples do not change significantly. Wherein, as varying the ratio of the stoichiometric index (3±δ) from 1.0 to 2.884, the emission peaks slightly red shift, the corresponding color coordinates increase a little, and the color temperatures decrease faintly.

[0146] As varying the ratio of the stoichiometric index (3±δ) from 2.89 to 3.35, the emission peaks slightly blue shift, the corresponding color coordinates decrease a little, and the color temperatures increase faintly.

[0147] FIG. 2 demonstrates that the halogen co-activated aluminate fluorescent material of the present invention has a wider spectral coverage and a higher luminous intensity than the commonly used silicate luminescent material. FIG. 9 demonstrates that a white LED photo-luminescent composition having high luminous efficiency, high color rendering index, low color temperature and high stability can be obtained by combining the fluorescent material in the present invention and the nitride red-emitting phosphor powder.

[0148] It has been demonstrated that fluorescent materials having the general formula: [Lu.sub.1−a−c−d−2/3bY.sub.aZ(Ln−1).sub.cΣ(Ln−2).sub.dM.sub.b].sub.3±δ[Al.sub.1−xGa.sub.x].sub.5(O.sub.1−1/2yX.sub.y).sub.12±1.5δ can be synthesized, which materials may be combined with nitride or silicate red-emitting phosphor powder to produce a white LED photo-luminescent composition with high luminous efficiency, high color rendering index, low light decay, and low color temperature. This product has a very important practical significance.

[0149] Although the disclosure has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims.

[0150] All publications, patents and patent applications mentioned in this specification are herein incorporated in their entirety by reference into the specification, to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated herein by reference. In addition, citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art to the present disclosure. To the extent that section headings are used, they should not be construed as necessarily limiting.