Silicate luminescent materials doped with metal nano particles and preparation methods therefor

Abstract

The invention belongs to the field of luminescent materials. Disclosed are silicate luminescent materials doped with metal nano particles and preparation methods there for. The silicate luminescent materials doped with metal nano particles are represented by the chemical formula:MLn.sub.1-xSiO.sub.4:xRE,yA; wherein M is one or two elements selected from Li, Na and K; Ln is one or two elements selected from Y, Sc, La and Lu; A is a metal nano particle selected from Ag, Au, Pt, Pd and Cu; RE is one or two ions selected from Eu, Gd, Tb, Tm, Sm, Ce and Dy; 0<x0.1; 0<y0.005. When silicate luminescent materials doped with metal nano particles of the invention are excitated by electron beam, they have higher luminescent efficiency. The luminescent materials are good to be used in field emission light source devices.

Claims

1. A silicate luminescent material doped with metal nano particles represented as: MLn.sub.1-xSiO.sub.4:xRE, containing A, wherein M is one or two elements selected from Li, Na and K; Ln is one or two elements selected from Y, Sc, La and Lu; A is a metal nano particle selected from Ag, Au, Pt, Pd and Cu; RE is one or two ions selected from Eu, Gd, Tb, Tm, Sm, Ce and Dy; x is a stoichiometric number in a range of 0<x0.1; y is a molar of A to M in a range of 0<y0.005.

2. The silicate luminescent material doped with metal nano particles according to claim 1, wherein x is in a range of 0.001x0.04, y is in a range of 0.00003y0.003.

3. A method for preparing silicate luminescent material doped with metal nano particles, comprising: S1. according to the stoichiometric ratio of corresponding elements in the chemical formula of MLn.sub.1-xSiO.sub.4:xRE containing A, weighing compound containing M, compound containing Ln, compound containing RE and silica aerogel containing A, then grinding and mixing to obtain mixed powders; S2, in air or in reducing atmosphere, calcining the mixed powders obtained from S1 at a constant temperature ranged from 800 C. to 1600 C. for 1 h to 10 h; then cooling to room temperature, taking out the calcined matter and grinding to obtain silicate luminescent material doped with metal nano particles represented as MLn.sub.1-xSiO.sub.4:xRE containing A; wherein M is one or two elements selected from Li, Na and K; Ln is one or two elements selected from Y, Sc, La and Lu; A is a metal nano particle selected from Ag, Au, Pt, Pd and Cu; RE is one or two ions selected from Eu, Gd, Tb, Tm, Sm, Ce and Dy; x is a stoichiometric number in a range of 0<x0.1; y is a molar ratio of A to M in a range of 0<y0.005.

4. The method for preparing silicate luminescent material doped with metal nano particles according to claim 3, wherein in S1, the compound containing M is selected from oxide of M, nitrate of M, carbonate of M and oxalate of M; the compound containing Ln is selected from oxide of Ln, nitrate of Ln, carbonate of Ln and oxalate of Ln; the compound containing RE is selected from oxide of RE, nitrate of RE, carbonate of RE and oxalate of RE.

5. The method for preparing silicate luminescent material doped with metal nano particles according to claim 3, wherein in S1, the silica aerogel containing A is prepared by the following steps: S11. weighing silica aerogel and adding into ethanol solution containing A ions or colloidal nanoparticles of A, then stirring at 50 C. to75 C. for 0.5 h to 3 h to thoroughly dissolve silica aerogel, obtaining mixed solution; wherein molar concentration of A ions or colloidal nanoparticles of A is in a range of 1.2510.sup.3 mol/L to 1.510.sup.5mol/L; S12. stirring and ultrasonically treating the mixed solution, then drying the mixed solution at 60 C. to 150 C. to remove solvent, obtaining dried matter; S13. grinding the dried matter into powders, calcining the powders at 600 C. to 1300 C. for 0.5 h to 3 h, cooling to room temperature to obtain silica aerogel containing A.

6. The method for preparing silicate luminescent material doped with metal nano particles according to claim 5, wherein in S11, molar ratio of silica aerogel to A ions or colloidal nanoparticles of A is in a range of 3.310.sup.4 to 328:1.

7. The method for preparing silicate luminescent material doped with metal nano particles according to claim 6, wherein in S11, aperture size of the silica aerogel is in a range of 20 nm to 100 nm, porosity is in a range of 92% to 98%.

8. The method for preparing silicate luminescent material doped with metal nano particles according to claim 3, wherein in S2, the reducing atmosphere is mixed gases of N.sub.2 and H.sub.2 in a volume ratio of 95:5.

9. The method for preparing silicate luminescent material doped with metal nano particles according to claim 3, wherein x is in a range of 0.001x0.04, y is in a range of 0.00003y0.003.

10. The method for preparing silicate luminescent material doped with metal nano particles according to claim 4, wherein x is in a range of 0.001x0.04, y is in a range of 0.00003y0.003.

11. The method for preparing silicate luminescent material doped with metal nano particles according to claim 5, wherein x is in a range of 0.001x0.04, y is in a range of 0.00003y0.003.

12. The method for preparing silicate luminescent material doped with metal nano particles according to claim 6, wherein x is in a range of 0.001x0.04, y is in a range of 0.00003y0.003.

13. The method for preparing silicate luminescent material doped with metal nano particles according to claim 7, wherein x is in a range of 0.001x0.04, y is in a range of 0.00003y0.003.

14. The method for preparing silicate luminescent material doped with metal nano particles according to claim 8, wherein x is in a range of 0.001x0.04, y is in a range of 0.00003y0.003.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a flow diagram showing the preparation of silicate luminescent materials doped with metal nano particles;

(2) FIG. 2 shows an emission spectrum of the silicate luminescent material doped with metal nano particles (NaY.sub.0.9SiO.sub.4: 0.1Tb.sup.3+containing Ag) of Example 8, compared to the luminescent material without Ag nanoparticles (NaY.sub.0.9SiO.sub.4: 0.1Tb.sup.3+) of Comparative Example 1. Curve a is an emission spectrum of the silicate luminescent material doped with metal nano particles (NaY.sub.0.9SiO.sub.4: 0.1Tb.sup.3+containing Ag) of Example 8, curve b is an emission spectrum of the luminescent material without Ag nanoparticles (NaY.sub.0.9SiO.sub.4: 0.1Tb.sup.3+) of Comparative Example 1.

DETAILED DESCRIPTION OF ILLUSTRATED EMBODIMENTS

(3) In one embodiment, the silicate luminescent materials doped with metal nano particles is represented as MLn.sub.1-xSiO.sub.4:xRE, containing A; wherein M is one or two elements selected from Li, Na and K; Ln is one or two elements selected from Y, Sc, La and Lu; A is a metal nano particle selected from Ag, Au, Pt, Pd and Cu; RE is one or two ions selected from Eu, Gd, Tb, Tm, Sm, Ce and Dy; x is a stoichiometric number in a range of 0<x0.1; y is a molar ratio of A to M in a range of 0<y0.005. Preferably, x is in a range of 0.001x0.04, y is in a range of 0.00003y0.003.

(4) As shown in FIG. 1, method for preparing the silicate luminescent materials doped with metal nano particles comprises the following steps:

(5) S1, preparing silica aerogel containing A;

(6) Firstly, silica aerogel was weighed and added into ethanol solution containing A ions or colloidal nanoparticles of A while stirring at 50 C. to 75 C. for 0.5 h to 3 h, silica aerogel was thoroughly dissolved to form mixed solution, where molar concentration of A ions or colloidal nanoparticles of A was in a range of 1.2510.sup.3 mol/L to 1.510.sup.5mol/L, and molar ratio of silica aerogel to A ions or colloidal nanoparticles of A was in a range of 3.310.sup.4 to 328:1.

(7) Next, the mixed solution was stirred, ultrasonically treated, then dried at 60 C. to 150 C. to remove solvent and obtain dried matter;

(8) At last, the dried matter was grinded into powders. The powders was calcined at 600 C. to 1300 C. for 0.5h to 3h, then cooled to room temperature to obtain silica aerogel containing A.

(9) S2. According to the stoichiometric ratio of corresponding elements in the chemical formula of MLn.sub.1-xSiO.sub.4:xRE, containing A, weighing compound containing M, compound containing Ln, compound containing RE and silica aerogel containing A, then grinding and mixing to obtain mixed powders;

(10) S3, in air or in reducing atmosphere, calcining the mixed powders obtained from S2 at a constant temperature ranged from 800 C. to 1600 C. for 1 h to 10 h; then cooling to room temperature, taking out the calcined matter and grinding to obtain silicate luminescent material doped with metal nano particles represented as MLn.sub.1-xSiO.sub.4:xRE, containing A. During the calcination, the compound containing RE subjected to pyrolysis or reducing atmosphere is reduced to RE metal element.

(11) M is one or two elements selected from Li, Na and K; Ln is one or two elements selected from Y, Sc, La and Lu; A is a metal nano particle selected from Ag, Au, Pt, Pd and Cu; RE is one or two ions selected from Eu, Gd, Tb, Tm, Sm, Ce and Dy; x is a stoichiometric number in a range of 0<x0.1; y is a molar ratio of A to M in a range of 0<y0.005.

(12) In S1 of the above preparation method, aperture size of the silica aerogel is preferably in a range of 20-100 nm, porosity is preferably in a range of 92% to 98%.

(13) In S2 of the above preparation method, the compound containing M is selected from oxide of M, nitrate of M, carbonate of M and oxalate of M; the compound containing Ln is selected from oxide of Ln, nitrate of Ln, carbonate of Ln and oxalate of Ln; the compound containing RE is selected from oxide of RE, nitrate of RE, carbonate of RE and oxalate of RE.

(14) When weighing the compound containing M, an excess of compound containing M of 10 mol % (molar percent) is preferred.

(15) In S3 of the above preparation method, the reducing atmosphere is preferably mixed gases of N.sub.2 and H.sub.2, the volume ratio of N.sub.2 to H.sub.2 is 95:5.

(16) The silicate luminescent materials doped with metal nano particles of the invention show relatively high luminescent efficiency under excitation by electron beam, thus can be used in field emission light source devices.

(17) The method for preparing silicate luminescent materials doped with metal nano particles of the present invention is simple, non-polluting, high-quality, low-cost, and can be widely used in the manufacture of luminescent materials.

(18) Further description of the present invention will be illustrated, which combined with preferred embodiments and the drawings.

Example 1

(19) NaY.sub.0.999SiO.sub.4: 0.001Tm.sup.3+ containing Ag

(20) Silica aerogel having an aperture size in a range of 20 nm to 100 nm and porosity in a range of 92% to 98% was used. Firstly, 0.3 g of silica aerogel was weighed and added into 10 mL of ethanol solution containing 1.510.sup.5 mol/L AgNO.sub.3 while stirring at 50 C. for 3 h, then ultrasonically treated for 10 min and dried at 60 C. The dried matter was grinded into powders. The powders were pre-calcined at 600 C. for 4 h. 0.7150 g of Y.sub.2(CO.sub.3).sub.3, 0.2543 g of Na.sub.2CO.sub.3 (in excess of 20%), 0.0010 g of Tm.sub.2(CO.sub.3).sub.3 and 0.2524 g of silica aerogel containing Ag were weighed, grinded and mixed to obtain mixed powders. In air atmosphere, the mixed powders were calcined constantly at 800 C. for 10 h. The obtained product was cooled to room temperature. The obtained silicate luminescent material doped with metal nano particles was represented as NaY.sub.0.999SiO.sub.4:0.001Tm.sup.3+ containing Ag.

Example 2

(21) LiLa.sub.0.992SiO.sub.4: 0.008Ce.sup.3+ containing Au

(22) Silica aerogel having an aperture size in a range of 20 nm to 100 nm and porosity in a range of 92% to 98% was used. Firstly, 0.4 g of silica aerogel was weighed and added into 20 mL of ethanol solution containing 2.34510.sup.5mol/L colloidal nanoparticles of Au while stirring at 60 C. for 2 h, then ultrasonically treated for 10 min and dried at 80 C. The dried matter was grinded into powders. The powders were pre-calcined at 800 C. for 2 h. 0.6464 g of La.sub.2O.sub.3, 0.1626 g of Li.sub.2CO.sub.3 (in excess of 10%), 0.0055 g of CeO.sub.2 and 0.2525 g of silica aerogel containing Au were weighed, grinded and mixed to obtain mixed powders. In reducing atmosphere of mixed gases of N.sub.2 and H.sub.2 in a volume ratio of 95:5, the mixed powders were calcined constantly at 1450 C. for 4 h. The obtained product was cooled to room temperature. The obtained silicate luminescent material doped with metal nano particles was represented as LiLa.sub.0.992SiO.sub.4: 0.008Ce.sup.3+ containing Au.

Example 3

(23) KLu.sub.0.96SiO.sub.4: 0.02Eu.sup.3+, 0.02Gd.sup.3+ containing Pt

(24) Silica aerogel having an aperture size in a range of 20 nm to 100 nm and porosity in a range of 92% to 98% was used. Firstly, 1.0 g of silica aerogel was weighed and added into 30 mL of ethanol solution containing 5.4310.sup.4 mol/L colloidal nanoparticles of Pt while stirring at 70 C. for 0.5 h, then ultrasonically treated for 10 min and dried at 150 C. The dried matter was grinded into powders. The powders were pre-calcined at 1000 C. for 4 h. 0.4044 g of KNO.sub.3, 0.7640 g of Lu.sub.2O.sub.3, 0.0137 g of Gd(NO.sub.3).sub.3, 0.0271 g of Eu(NO.sub.3).sub.3 and 0.2526 g of silica aerogel containing Pt were weighed, grinded and mixed to obtain mixed powders. In air atmosphere, the mixed powders were calcined constantly at 1600 C. for 1 h. The obtained product was cooled to room temperature. The obtained silicate luminescent material doped with metal nano particles was represented as KLu.sub.0.96SiO.sub.4: 0.02Eu.sup.3+, 0.02Gd.sup.3+ containing Pt

Example 4

(25) Na.sub.0.9Li.sub.0.1Sc.sub.0.2Y.sub.0.792SiO.sub.4: 0.008Dy.sup.3+ containing Pd

(26) Silica aerogel having an aperture size in a range of 20 nm to 100 nm and porosity in a range of 92% to 98% was used. Firstly, 0.28 g of silica aerogel was weighed and added into 15 mL of ethanol solution containing 1.226610.sup.4mol/L colloidal nanoparticles of Pd while stirring at 60 C. for 2 h, then ultrasonically treated for 10 min and dried at 70 C. The dried matter was grinded into powders. The powders were pre-calcined at 900 C. for 2 h. 0.2003 g of Na.sub.2NO.sub.3(in excess of 5%), 0.0163 g of Li.sub.2CO.sub.3(in excess of 10%), 0.3577 g of Y.sub.2O.sub.3 , 0.0060 g of Dy.sub.2O.sub.3 and 0.2524 g of silica aerogel containing Pd were weighed, grinded and mixed to obtain mixed powders. In air atmosphere, the mixed powders were calcined constantly at 1350 C. for 4 h. The obtained product was cooled to room temperature. The obtained silicate luminescent material doped with metal nano particles was represented as Na.sub.0.9Li.sub.0.1Sc.sub.0.2Y.sub.0.792SiO.sub.4: 0.008Dy.sup.3+ containing Pd.

Example 5

(27) NaLu.sub.0.98SiO.sub.4: 0.02Tb.sup.3+ containing Ag

(28) Silica aerogel having an aperture size in a range of 20 nm to 100 nm and porosity in a range of 92% to 98% was used. Firstly, 0.35 g of silica aerogel was weighed and added into 25 mL of ethanol solution containing 7.0810.sup.4mol/L AgNO.sub.3 while stirring at 65 C. for 1.5 h, then ultrasonically treated for 10 min and dried at 120 C. The dried matter was grinded into powders. The powders were pre-calcined at 1000 C. for 2 h. 0.2680 g of Na.sub.2C.sub.2O.sub.4, 1.2034 g of Lu.sub.2(C.sub.2O.sub.4).sub.3, 0.0233 g of Tb.sub.2(C.sub.2O.sub.4).sub.3 and 0.2523 g of calcined silica aerogel were weighed, grinded and mixed to obtain mixed powders. In reducing atmosphere of mixed gases of N.sub.2 and H.sub.2 in a volume ratio of 95:5, the mixed powders were calcined constantly at 1400 C. for 6 h. The obtained product was cooled to room temperature. The obtained silicate luminescent material doped with metal nano particles was represented as NaLu.sub.0.98SiO.sub.4: 0.02Tb.sup.3+ containing Ag.

Example 6

(29) NaY.sub.0.95SiO.sub.4: 0.05Sm.sup.3+ containing Ag

(30) Silica aerogel having an aperture size in a range of 20 nm to 100 nm and porosity in a range of 92% to 98% was used. Firstly, 0.3 g of silica aerogel was weighed and added into 20 mL of ethanol solution containing 1.2510.sup.3 mol/L AgNO.sub.3 while stirring at 60 C. for 2 h, then ultrasonically treated for 10 min and dried at 100 C. The dried matter was grinded into powders. The powders were pre-calcined at 800 C. for 2 h. 0.3400 g of NaNO.sub.30.4290 g of Y.sub.2O.sub.3, 0.0349 g of Sm.sub.2O.sub.3 and 0.2525 g of calcined silica aerogel were weighed, grinded and mixed to obtain mixed powders. In air atmosphere, the mixed powders were calcined constantly at 1200 C. for 6 h. The obtained product was cooled to room temperature. The obtained silicate luminescent material doped with metal nano particles was represented as NaY.sub.0.95SiO.sub.4: 0.05 Sm.sup.3+ containing Ag.

Example 7

(31) KLa.sub.0.99SiO.sub.5: 0.01Ce.sup.3+ containing Cu

(32) Silica aerogel having an aperture size in a range of 20 nm to 100 nm and porosity in a range of 92% to 98% was used. Firstly, 0.4 g of silica aerogel was weighed and added into 15 mL of ethanol solution containing 3.126610.sup.4 mol/L colloidal nanoparticles of Cu while stirring at 60 C. for 1.5 h, then ultrasonically treated for 10 min and dried at 70 C. The dried matter was grinded into powders. The powders were pre-calcined at 800 C. for 2 h. 0.2764 g of K.sub.2CO.sub.3 , 0.6451 g of La.sub.2O.sub.3, 0.0108 g of Ce.sub.2(C.sub.2O.sub.4).sub.3 and 0.2527 g of silica aerogel containing Cu were weighed, grinded and mixed to obtain mixed powders. In reducing atmosphere of mixed gases of N.sub.2 and H.sub.2 in a volume ratio of 95:5, the mixed powders were calcined constantly at 1500 C. for 4 h. The obtained product was cooled to room temperature. The obtained silicate luminescent material doped with metal nano particles was represented as KLa.sub.0.99SiO.sub.5: 0.01Ce.sup.3+ containing Cu.

Example 8

(33) NaY.sub.0.9SiO.sub.4: 0.1Tb.sup.3+ containing Ag

(34) Silica aerogel having an aperture size in a range of 20 nm to 100 nm and porosity in a range of 92% to 98% was used. Firstly, 0.35 g of silica aerogel was weighed and added into 25 mL of ethanol solution containing 7.0810.sup.4mol/L AgNO.sub.3 while stirring at 65 C. for 1.5 h, then ultrasonically treated for 10 min and dried at 120 C. The dried matter was grinded into powders. The powders were pre-calcined at 800 C. for 2 h. 0.2332 g of Na.sub.2CO.sub.3 (in excess of 10%), 0.4065 g of Y.sub.2O.sub.3, 0.0748 g of Tb.sub.4O.sub.7 and 0.2523 g of calcined silica aerogel were weighed, grinded and mixed to obtain mixed powders. In reducing atmosphere of mixed gases of N.sub.2 and H.sub.2 in a volume ratio of 95:5, the mixed powders were calcined constantly at 1250 C. for 6 h. The obtained product was cooled to room temperature. The obtained silicate luminescent material doped with metal nano particles was represented as NaY.sub.0.9SiO.sub.4: 0.1Tb.sup.3+ containing Ag.

Comparative Example 1

(35) NaY.sub.0.9SiO.sub.4: 0.1Tb.sup.3+

(36) 0.2332 g of Na.sub.2CO.sub.3 (in excess of 10 mol %), 0.4065 g of Y.sub.2O.sub.3, 0.0748 g of Tb.sub.4O.sub.7 and 0.2523 g of silica aerogel were weighed, grinded and mixed to obtain mixed powders. In reducing atmosphere of mixed gases of N.sub.2 and H.sub.2 in a volume ratio of 95:5, the mixed powders were calcined constantly at 1250 C. for 6 h. The obtained product was cooled to room temperature. The obtained luminescent material was represented by the chemical formula of NaY.sub.0.9SiO.sub.4: 0.1Tb.sup.3+.

(37) FIG. 2 shows an emission spectrum of the silicate luminescent material doped with metal nano particles (NaY.sub.0.9SiO.sub.4: 0.1Tb.sup.3+containing Ag) of Example 8, compared to the luminescent material without Ag nanoparticles (NaY.sub.0.9SiO.sub.4: 0.1Tb.sup.3+) of Comparative Example 1. Curve a is an emission spectrum of the silicate luminescent material doped with metal nano particles (NaY.sub.0.9SiO.sub.4: 0.1Tb.sup.3+ containing Ag) of Example 8, curve b is an emission spectrum of the luminescent material without Ag nanoparticles (NaY.sub.0.9SiO.sub.4: 0.1Tb.sup.3+) of Comparative Example 1.

(38) As shown in FIG. 2, under excitation by cathode ray at 5 KV, luminescent intensity of the silicate luminescent material doped with metal nano particles containing Ag nanoparticles (NaY.sub.0.9SiO.sub.4: 0.1Tb.sup.3+ containing Ag) is increased by 30%, compared to the luminescent material without Ag nanoparticles.

(39) While the present invention has been described with reference to particular embodiments, it will be understood that the embodiments are illustrative and that the invention scope is not so limited. Alternative embodiments of the present invention will become apparent to those having ordinary skill in the art to which the present invention pertains. Such alternate embodiments are considered to be encompassed within the spirit and scope of the present invention. Accordingly, the scope of the present invention is described by the appended claims and is supported by the foregoing description.