Patent Application
20150284631
The present invention relates to luminescent material technology. More particularly, the invention relates to a silicate luminescent material and preparation method thereof.
In the 1960s, Ken Shoulder proposed ideas based on field emissive arrays (FEAs) electron beam microelectronic devices, thus, to design and produce panel display and light resource devices by using FEAs has drawn the public's attention. Similar to the working principle of conventional cathode ray tube (CRT), such new field emission display lights and forms images by electron beam bombardment on red, green blue trichromatic fluorescent powder. Field emission display has potential advantages in luminance, visual angle, response time, working temperature range, energy consumption and other aspects.
A key to prepare field emission display of high performances is to prepare luminescent material of excellent performance. At present, luminescent material provided in field emission display are commonly luminescent material of traditional cathode ray tube and projection television kinescope, such as sulfide series, oxide series and oxysulfide series luminescent material. As for sulfide series and oxysulfide series luminescent material, they have high luminance and electrical conductivity, but, under the large electron beam bombardment, they prone to decompose into elemental sulfur, which can poison the tip of cathode and produce other precipitates covering the luminescent material, so as to reduce the luminescent efficiency of luminescent material, and shorten the life of a field emission display.
Due to defects presence in sulfide and oxysulfide luminescent material, researchers intend to replace the sulfide and oxysulfide series luminescent materials with silicate luminescent material, but traditional silicate luminescent material universally has a problem of low luminescent efficiency.
In view of this, the present invention provides a silicate luminescent material and preparation method thereof, said silicate luminescent material has high luminescent efficiency.
A silicate luminescent material, wherein said silicate luminescent material has a general molecular formula of Li2Ca1-xSiO4:Tbx,My, wherein, Tb and M are doped particles that doped in Li2Ca1-xSiO4; M is selected from at least one of Ag, Au, Pt, Pd, and Cu metal nanoparticles, x has a value range of 0<x≦0.2, y is a molar ratio of M to Si and y has a value range of 0<y≦1×10−2.
In one embodiment of the present invention, said x has a value range of 0.02≦x≦0.10.
In one embodiment of the present invention, said y has a value range of 1×105≦y≦5×10−3.
The silicate luminescent material doped with metal particles effectively overcomes the structure defect of silicate luminescent material, which decreases non radiative transition probability and greatly increases luminescent efficiency of the silicate luminescent material in a same excitation condition without changing a wavelength of emitted light. The silicate luminescent material has good stability, overcomes the defect that sulfide and oxysulfide series luminescent materials are easy to decompose, and can replace the sulfide and oxysulfide series luminescent materials in field emission display.
A method for preparing a silicate luminescent material, comprising:
adding silicon dioxide aerogel into a solution of salt of metal M according to molar ratio of M to Si which defined as y, mixing and stirring uniformly said silicon dioxide aerogel and said solution of salt of metal M at 50° C. to 75° C. to obtain mixture solution, sonicating said mixture solution, drying the mixture solution obtained from sonicating at 60° C. to 150° C., grinding mixture solid obtained from drying uniformly, calcining said mixture solid at 600° C. to 1200° C. to obtain silicon dioxide aerogel containing M ion, said M is selected from at least one of Ag, Au, Pt, Pd, and Cu metal nanoparticles, y has a value range of 0<y≦1×10−2;
weighing source compound of Li, source compound of Ca, source compound of Tb and said silicon dioxide aerogel containing M ion according to molar ratio of Li, Ca, Tb and Si elements at 2:(1−x):x:1, mixing and grinding uniformly to obtain mixture material, x has a value range of 0<x≦0.2; and
calcining said mixture material at 500° C. to 1000° C., and reducing said mixture material under reducing atmosphere at 800° C. to 1200° C., cooling mixture material obtained from reducing to room temperature, grinding to obtain silicate luminescent material has a general molecular formula of Li2Ca1-xSiO4:Tbx,My, Tb and M are doped particles that doped in Li2Ca1-xSiO4.
In one embodiment of the present invention, a solute in said solution of salt of metal M is at least one of HAuCl4, H2PtCl6, AgNO3, PdCl2.2H2O and Cu(NO3)2, and solvent in said solution of salt of metal M is ethanol.
In one embodiment of the present invention, a concentration of solution of salt of metal M is in a range of 5×10−6 to 1×10−2 mol/L.
In one embodiment of the present invention, said source compound of Li is one of lithium oxide, lithium carbonate, lithium nitrate, lithium acetate and lithium oxalate, said source compound of Ca is one of calcium oxide, calcium carbonate, calcium nitrate, calcium acetate and calcium oxalate, and said source compound of Tb is one of terbium oxide, terbium carbonate, terbium nitrate, terbium acetate and terbium oxalate.
In one embodiment of the present invention, said reducing atmosphere is CO reducing atmosphere, or H2 reducing atmosphere, or a mixed reducing atmosphere of a volume ratio of 95% N2 and a volume ratio of 5% H2.
In one embodiment of the present invention, said x has a value range of 0.02≦x≦0.10; said y has a value range of 1×10−5≦y≦5×10−3.
The above method for preparing silicate luminescent material, comprising: first adsorb metal ion by using silicon dioxide aerogel to obtain silicon dioxide aerogel containing metal ion, then use source compound of Li, source compound of Ca, source compound of Tb and said silicon dioxide aerogel containing metal ion as raw material, and reduce said metal ion to be metal elementary substance, finally to obtain silicate luminescent material has a general molecular formula of Li2Ca1-xSiO4:Tbx,My. Said preparation methods of silicate luminescent material are of simple process, low cost, no pollution, easy to control, easy to produce in industry, and the silicate luminescent material obtained has high luminescent efficiency and high stability, and also has broad application prospects in field emission display.
Further description of the silicate luminescent material and preparation method thereof will be illustrated combined with embodiments and drawings.
One embodiment of the present invention provides a silicate luminescent material, wherein said silicate luminescent material has a general molecular formula of Li2Ca1-xSiO4:Tbx,My, wherein, Tb and M are nano particles doped in Li2Ca1-xSiO4; M is selected from at least one of Ag, Au, Pt, Pd, and Cu metal nanoparticles, x has a value range of 0<x≦0.2, y is a molar ratio of M to Si and y has a value range of 0<y≦1×10−2.
Further, in other embodiment preferably, said x has a value range of 0.02≦x≦0.10, said y has a value range of 1×10−5≦y≦5×10−3.
While, one embodiment of the present invention also provides a method for preparing a silicate luminescent material, refers to
Step S110, adding silicon dioxide aerogel into a solution of salt of metal M according to molar ratio of M to Si which defined as y, mixing and stirring uniformly said silicon dioxide aerogel and said solution of salt of metal M at 50° C. to 75° C. to obtain mixture solution, sonicating said mixture solution, drying the mixture solution obtained from sonicating at 60° C. to 150° C., grinding mixture solid obtained from drying uniformly, calcining said mixture solid at 600° C. to 1200° C. to obtain silicon dioxide aerogel containing M ion.
Wherein, said M is selected from at least one of Ag, Au, Pt, Pd, and Cu metal nanoparticles, y has a value range of 0<y≦1×10−2. A solute in said solution of salt of metal M is at least one of HAuCl4, H2PtCl6, AgNO3, PdCl2.2H2O and Cu(NO3)2, and solvent in said solution of salt of metal M is ethanol. In this embodiment of the present invention, a concentration of solution of salt of metal M is in a range of 5×10−6 to 1×10−2 mol/L.
Step S120, weighing source compound of Li, source compound of Ca, source compound of Tb and said silicon dioxide aerogel containing M ion according to molar ratio of Li, Ca, Tb and Si elements at 2:(1−x):x:1, mixing and grinding uniformly to obtain mixture material.
Wherein, x has a value range of 0<x≦0.2. Said source compound of Li is one of lithium oxide, lithium carbonate, lithium nitrate, lithium acetate and lithium oxalate. Said source compound of Ca is one of calcium oxide, calcium carbonate, calcium nitrate, calcium acetate and calcium oxalate. Said source compound of Tb is one of terbium oxide, terbium carbonate, terbium nitrate, terbium acetate and terbium oxalate.
Step S130, calcining said mixture material at 500° C. to 1000° C., and reducing said mixture material under reducing atmosphere at 800° C. to 1200° C., cooling mixture material obtained from reducing to room temperature, grinding to obtain silicate luminescent material has a general molecular formula of Li2Ca1-xSiO4:Tbx,My, wherein, Tb and M are doped particles that doped in Li2Ca1-xSiO4.
In this embodiment of the present invention, said reducing atmosphere is CO reducing atmosphere, or H2 reducing atmosphere, or a mixed reducing atmosphere of a volume ratio of 95% N2 and a volume ratio of 5% H2.
The silicate luminescent material doped with metal particles effectively overcomes the structure defect of silicate luminescent material, which decreases non radiative transition probability and greatly increases luminescent efficiency of the silicate luminescent material in a same excitation condition without changing a wavelength of emitted light. The silicate luminescent material has good stability, overcomes the defect that sulfide and oxysulfide series luminescent materials are easy to decompose, and can replace the sulfide and oxysulfide series luminescent materials in field emission display.
The above method for preparing silicate luminescent material, comprising: first adsorb metal ion by using silicon dioxide aerogel to obtain silicon dioxide aerogel containing metal ion, then use source compound of Li, source compound of Ca, source compound of Tb and said silicon dioxide aerogel containing metal ion as raw material, and reduce said metal ion to be metal elementary substance, finally to obtain silicate luminescent material has a general molecular formula of Li2Ca1-xSiO4:Tbx,My. Said preparation methods of silicate luminescent material are of simple process, low cost, no pollution, easy to control, easy to produce in industry, and the silicate luminescent material obtained has high luminescent efficiency and high stability, and also has broad application prospects in field emission display.
Further description of the silicate luminescent material of different compose, preparation method therefor and performance will be illustrated combined with embodiments.
Weighing 0.7212 g of SiO2 aerogel, dissolving it in 12 ml of ethanol solution containing HAuCl4 where the concentrate of HAuCl4 is 1×10−2 mol/L. Stirring the mixture solution of SiO2 aerogel and ethanol solution containing HAuCl4 at 75° C. for 0.5 h, and sonicating the mixture solution for 10 minutes, then drying at 150° C. Grinding mixture solid obtained from drying, calcining said mixture solid at 1200° C. for 0.5 hours to obtain SiO2 aerogel containing Au3+.
Weighing 0.1195 g of Li2O, 0.1904 g of CaO, 0.1121 g of Tb4O7, and 0.2405 g of SiO2 aerogel containing Au3+to obtain mixture material.
Grinding mixture material uniformly in agate mortar to form mixture material powder, then placing the mixture material powder into corundum crucible, heating the mixture material powder in muffle furnace at 500° C. for 15 hours and then calcining the mixture material powder in tube furnace under C reducing atmosphere at 1000° C. for 2 hours to reduce Au3+ into Au, cooling to room temperature, and grinding to obtain silicate luminescent material containing Au has a molecular formula of Li2Ca0.85 SiO4:Tb0.15,Au1×10
Weighing 0.3606 g of SiO2 aerogel, dissolving it in 6 ml of ethanol solution containing H2PtCl6 where the concentrate of H2PtCl6 is 5×10−3 mol/L. Stirring the mixture solution of SiO2 aerogel and ethanol solution containing H2PtCl6 at 50° C. for 3 h, and sonicating the mixture solution for 10 minutes, then drying at 60° C. Grinding mixture solid obtained from drying, calcining said mixture solid at 600° C. for 4 hours to obtain SiO2 aerogel containing Pt4+.
Weighing 0.2955 g of Li2CO3, 0.3924 g of CaCO3, 0.0199 g of Tb2(CO3)3, and 0.2404 g of SiO2 aerogel containing Pt4+ to obtain mixture material.
Grinding mixture material uniformly in agate mortar to form mixture material powder, then placing the mixture material powder into corundum crucible, heating the mixture material powder in muffle furnace at 1000° C. for 2 hours and then calcining the mixture material powder in tube furnace under CO reducing atmosphere at 1200° C. for 0.5 hours to reduce Pt4+ into Pt, cooling to room temperature, and grinding to obtain silicate luminescent material containing Pt has a molecular formula of Li2Ca0.98SiO4:Tb0.02,Pt5×10
Weighing 0.3606 g of SiO2 aerogel, dissolving it in 7.5 ml of ethanol solution containing AgNO3 where the concentrate of AgNO3 is 2×10−4 mol/L. Stirring the mixture solution of SiO2 aerogel and ethanol solution containing AgNO3 at 60° C. for 2 h, and sonicating the mixture solution for 10 minutes, then drying at 80° C. Grinding mixture solid obtained from drying, calcining said mixture solid at 800° C. for 2 hours to obtain SiO2 aerogel containing Ag+.
Weighing 0.2955 g of Li2CO3, 0.2016 g of CaO, 0.0747 g of Tb4O7, and 0.2524 g of SiO2 aerogel containing Ag+ to obtain mixture material.
Grinding mixture material uniformly in agate mortar to form mixture material powder, then placing the mixture material powder into corundum crucible, heating the mixture material powder in muffle furnace at 600° C. for 4 hours and then calcining the mixture material powder in tube furnace under a mixed reducing atmosphere of a volume ratio of 95% N2 and a volume ratio of 5% H2 at 1000° C. for 4 hours to reduce Ag+ into Ag, cooling to room temperature, and grinding to obtain silicate luminescent material containing Ag has a molecular formula of Li2Ca0.90SiO4:Tb0.10,Ag2.5×10
Weighing 0.3005 g of SiO2 aerogel, dissolving it in 10 ml of ethanol solution containing PdCl2.2H2O where the concentrate of PdCl2.2H2O is 5×10−6 mol/L. Stirring the mixture solution of SiO2 aerogel and ethanol solution containing PdCl2.2H2O at 65° C. for 1.5 h, and sonicating the mixture solution for 10 minutes, then drying at 120° C. Grinding mixture solid obtained from drying, calcining said mixture solid at 1100° C. for 2 hours to obtain SiO2 aerogel containing Pd4+.
Weighing 0.4076 g of Li2C2O4, 0.4096 g of CaC2O4, 0.2327 g of Tb2(C2O4)3, and 0.2524 g of SiO2 aerogel containing Pd4+ to obtain mixture material.
Grinding mixture material uniformly in agate mortar to form mixture material powder, then placing the mixture material powder into corundum crucible, heating the mixture material powder in muffle furnace at 700° C. for 5 hours and then calcining the mixture material powder in tube furnace under H2 reducing atmosphere at 800° C. for 6 hours to reduce Pd4+ into Pd, cooling to room temperature, and grinding to obtain silicate luminescent material containing Pd has a molecular formula of Li2Ca0.80SiO4:Tb0.20,Pd1×10
Weighing 0.3606 g of SiO2 aerogel, dissolving it in 12 ml of ethanol solution containing Cu(NO3)2 where the concentrate of Cu(NO3)2 is 5×10−5 mol/L. Stirring the mixture solution of SiO2 aerogel and ethanol solution containing Cu(NO3)2 at 70° C. for 1 h, and sonicating the mixture solution for 10 minutes, then drying at 70° C. Grinding mixture solid obtained from drying, calcining said mixture solid at 800° C. for 2 hours to obtain SiO2 aerogel containing Cu2+.
Weighing 0.5516 g of LiNO3, 0.6232 g of Ca(NO3)2, 0.0689 g of Tb(NO3)3, and 0.2404 g of SiO2 aerogel containing Cu2+ to obtain mixture material.
Grinding mixture material uniformly in agate mortar to form mixture material powder, then placing the mixture material powder into corundum crucible, heating the mixture material powder in muffle furnace at 600° C. for 4 hours and then calcining the mixture material powder in tube furnace under a mixed reducing atmosphere of a volume ratio of 95% N2 and a volume ratio of 5% H2 at 1000° C. for 6 hours to reduce Cu2+ into Cu, cooling to room temperature, and grinding to obtain silicate luminescent material containing Cu has a molecular formula of Li2Ca0.95SiO4:Tb0.05,Cu1×10
Weighing 0.3606 g of SiO2 aerogel, dissolving it in 12 ml of ethanol solution containing AgNO3 where the concentrate of AgNO3 is 2.5×10−4 mol/L. Stirring the mixture solution of SiO2 aerogel and ethanol solution containing AgNO3 at 65° C. for 1.5 h, and sonicating the mixture solution for 10 minutes, then drying at 120° C. Grinding mixture solid obtained from drying, calcining said mixture solid at 900° C. for 3 hours to obtain SiO2 aerogel containing Ag+.
Weighing 0.2955 g of Li2CO3, 0.4506 g of CaC2O4, 0.1396 g of Tb2(C2O4)3, and 0.2404 g of SiO2 aerogel containing Ag+ to obtain mixture material.
Grinding mixture material uniformly in agate mortar to form mixture material powder, then placing the mixture material powder into corundum crucible, heating the mixture material powder in muffle furnace at 500° C. for 10 hours and then calcining the mixture material powder in tube furnace under H2 reducing atmosphere at 1100° C. for 3 hours to reduce Ag+ into Ag, cooling to room temperature, and grinding to obtain silicate luminescent material containing Ag has a molecular formula of Li2Ca0.88SiO4:Tb0.12,Ag5×10
Weighing 0.7212 g of SiO2 aerogel, dissolving it in 15 ml of ethanol solution containing AgNO3 and HAuCl4 where the concentrate of AgNO3 is 1×10−3 mol/L and the concentrate of HAuCl4 is 1×10−3 mol/L. Stirring the mixture solution of SiO2 aerogel and ethanol solution containing AgNO3 and HAuCl4 at 60° C. for 2 h, and sonicating the mixture solution for 10 minutes, then drying at 80° C. Grinding mixture solid obtained from drying, calcining said mixture solid at 1000° C. for 4 hours to obtain SiO2 aerogel containing Ag+ and Au3+.
Weighing 0.5279 g of CH3COOLi, 0.5821 g of (CH3COO)2Ca, 0.1075 g of (CH3COO)3Tb, and 0.2524 g of SiO2 aerogel containing Ag+ and Au3+ to obtain mixture material.
Grinding mixture material uniformly in agate mortar to form mixture material powder, then placing the mixture material powder into corundum crucible, heating the mixture material powder in muffle furnace at 700° C. for 8 hours and then calcining the mixture material powder in tube furnace under a mixed reducing atmosphere of a volume ratio of 95% N2 and a volume ratio of 5% H2 at 900° C. for 5 hours to reduce Ag+ and Au3+ into Ag and Au, cooling to room temperature, and grinding to obtain silicate luminescent material containing Ag and Au has a molecular formula of Li2Ca0.92SiO4:Tb0.08,(Ag0.5Au0.5)1.25×10
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 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.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/CN2012/083880 | 10/31/2012 | WO | 00 |
