CN103243318B - Preparation method of broadband gradient LED (Light-emitting Diode) fluorescent film - Google Patents

Preparation method of broadband gradient LED (Light-emitting Diode) fluorescent film Download PDF

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CN103243318B
CN103243318B CN201310178877.5A CN201310178877A CN103243318B CN 103243318 B CN103243318 B CN 103243318B CN 201310178877 A CN201310178877 A CN 201310178877A CN 103243318 B CN103243318 B CN 103243318B
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preparation
led fluorescent
powder
fluorescent powder
wideband gradient
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CN103243318A (en
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李廷凯
李晴风
张拥军
陈建国
唐冬汉
虞爱民
谭丽霞
李勇
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HUNAN PROV SCIENCE AND TECHNOLOGY RESEARCH AND DEVELOPMENT INST
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Abstract

The invention provides a preparation method of a broadband gradient LED (Light-emitting Diode) fluorescent film. The preparation method is characterized in that broadband gradient LED fluorescent powder serves as a raw material; a uniform multicolour (red, green, blue and the like) fluorescent material film is deposited on an LED device or an LED lampshade gasket by a suspension method or a sol-gel method; and the broadband gradient LED fluorescent film prepared by the method has uniform isotropic color temperatures. The preparation method can be used for manufacturing and massively producing high-performance white LEDs with same performance, and can be used for preparing white LED devices, which can emit light approximating to sunlight, with high photoelectric conversion rates and high color rendering indexes. The broadband gradient LED fluorescent powder has a special structure and composition, and is good in dispersity, high in stacking density, great in scattering intensity and high in light-emitting efficiency.

Description

A kind of preparation method of wideband gradient LED fluorescent film
Technical field
The present invention relates to LED solid-state lighting system and application thereof, particularly the design and preparation method thereof of wideband gradient LED fluorescent film.
Background technology
The visible light emitting diode LED of the first practical application is developed from the Ni Kehelunyake (Nick Holonyak Jr.) of General Electric Corporation in 1962, particularly late nineteen nineties in last century third generation semiconductor material GaN technology breakthrough cause lighting field third time revolution since, experience the development of 50 years, LED is little because having volume, high brightness, low (1/8 to 1/10 of the incandescent-lamp bulb of current consumption, 1/2 of power saving fluorescent lamp), life-span long (more than 120,000 hours), high-level efficiency, low in calories, environmental protection is (without Hg, the pollutions such as Pb), can start by low pressure low current, response is fast, the resistance to punching of antidetonation, can planar package, easy exploiting becomes the number of advantages such as ultra-thin short and small product, be widely used in building and scenery lighting, large screen display, traffic lights, pilot lamp, televisor, the size dimension backlight such as mobile phone and digital camera, the solar energy LED illuminate, automotive lighting, special lighting and the numerous areas such as military.LED is replacing traditional incandescent light, power saving fluorescent lamp etc. simultaneously becomes energy-conservation, the economic environment-friendly type head light of a new generation, is described as 21 century green light source.
Photodiode (LEDs) is the solid condition apparatus converting electrical energy into light, generally comprises one or more quantum well and is clipped between the p-type of two contrary doped layers and type n semiconductor material.When bias voltage is applied on two doped layers, hole and electronics are injected in quantum well, and they excite compound there and produce light.These light emit from the quantum well of described LED and all surface.
Usually, LED can not excite from their quantum well the white light directly produced.Be converted to white light from LED blue light, need the yellow fluorescent material of blue light by LED and surrounding, the gold-tinted that polymkeric substance or dyestuff send combines.Such as, typical fluorescent material is that the yttrium aluminum garnet (YAG:Ce fluorescent material) of cerium dopping [checks the white LED model NSPW300BS of Ya chemical company, NSPW312BS etc.; Cree.RTM company, the photodiode of EZBright.TM and US Patent No. 5959316 etc.].These fluorescent materials, under the exciting of the blue light of LED, produce sodium yellow.The blue light of some of LED is constant by fluor, and a large amount of blue lights is absorbed by fluorescent material, and frequency conversion is sodium yellow.The blue light that LED sends and the fluorescent material sodium yellow that is excited combines, and defines white light.In order to improve the colour rendering index of white light, blue led also can combine with green and red fluorescence material, or combines with yellow and red fluorescence material and form the white light of similar sunlight.Another kind method forms white light from by polychrome (red, green, blue) fluorescent material around it of LED purple light or ultraviolet excitation.In addition, three-color LED (red, green, blue) combination also can form white light.Because the luminous efficiency of green LED is lower, usually use four LED(mono-red, two is green, and one is blue) form white light, just expensive.
At present most ordinary method is that fluorescent material layer is coated in LED on: first fluorescent material is mixed mutually with epoxy resin or organosilicon polymer, then with syringe or nozzle, their are applied on the led device.But, make in this way, be very difficult to geometrical shape and the thickness of the fluorescent material layer controlled.Consequently, measured by different during transition material from the different angular emission light out of LED, the visual angle function as LED can be caused like this to be non-homogeneous colour temperature.Be difficult to the geometrical shape and the thickness that control fluorescent material layer owing to using aforesaid method, therefore, the White LED s of same batch is difficult to repeat manufacture and keep same performance.
For the method that the another kind of the LED applied is traditional be adopt mould plate technique [European patent application EP 1198016A2].Multiple LED component is disposed on substrate, keeps suitable distance between each adjacent LED.Masterplate provides the perforate having and align with LED, its aperture slightly larger than LED component size and masterplate slightly thicker than LED component.This masterplate is positioned on substrate, makes each perforate corresponding with the LED of each.Then, fluorescent material is mixed with organosilicon polymer and the opening portion being deposited on mould to cover each LED component.After filling orifice, fluorescent material and organosilicon polymer, can be solidified by heat or light.
Above-mentioned syringe method and mould plate technique, be all difficult to control the geometrical shape of fluorescent material and thickness.Use template, fluorescent material may not exclusively be filled, and causes the fluorescent material skewness on LED.The composition of the fluor contained also may be bonded in template, thus the amount making to be coated in fluorescent material on LED reduces.In template, the opening portion in hole also may unjustified LED component.These problems all may cause LED have colour temperature heterogeneous and with batch White LED s be difficult to repeat manufacture and keep same performance.
If can fluorescent material film on direct plating on the led device, or on LED lamp cover liner the fluorescent material film of depositing homogeneous, to obtain each to uniform colour temperature. high performance White LED s can manufacture and produce in enormous quantities simultaneously, and keeps same performance.If particularly can colors (RGB) fluorescent material film of wideband gradient on direct plating on the led device, or on LED lamp cover liner polychrome (RGB etc.) fluorescent material film of depositing homogeneous, then can prepare and there is high optoelectronic transformation efficiency and the high color rendering index (CRI) i.e. White LED devices of approximate sunlight.
At present, the preparation method of LED fluorescent powder mainly contains high temperature solid phase synthesis, sol-gel method, coprecipitation method, sluggish precipitation, combustion synthesis method, spray pyrolysis etc., the difference of each method is mainly reflected in how to obtain the good presoma of performance (Precursor) aspect, and its relative merits are in table 1.
The relative merits of table 1 fluorescent material preparation method compare
Summary of the invention
For the deficiencies in the prior art, the present invention aims to provide a kind of preparation method of wideband gradient LED fluorescent film, this preparation method adopts suspension and sol-gel films Technology, colors (RGB) fluorescent material film of wideband gradient on direct plating on the led device, or on LED lamp cover liner polychrome (RGB etc.) fluorescent material film of depositing homogeneous, the wideband gradient LED fluorescent film that the method is prepared has each to uniform colour temperature. can manufacture and produce in enormous quantities high performance White LED s simultaneously, and keep same performance, can prepare and there is high optoelectronic transformation efficiency and the high color rendering index (CRI) i.e. White LED devices of approximate sunlight.
The preparation of this film make use of a kind of wideband gradient LED fluorescent powder, and it has special gradient-structure and different chemical constitutions, and glow frequency is wider than general fluorescent material, good dispersity, tap density is high, and scattering strength is large, luminous efficiency is high, the more approximate and natural light of the light sent after being excited.The preparation method of described wideband gradient LED fluorescent powder adopts micrometer fluorescent powder crystal grain as crystal seed, and identical with crystalline structure and pure phase micro/nano level that chemical composition is different or nano level fluorescent material mix mutually, at high temperature epitaxy growth forms wideband gradient LED fluorescent powder of the present invention.
For achieving the above object, technical scheme of the present invention is:
A preparation method for wideband gradient LED fluorescent film, is selected from one of following two kinds of methods:
Method one is suspension method, and concrete steps are:
1) add in organic reagent by wideband gradient LED fluorescent powder, forming mass concentration is the suspension of 2%-10%; Described organic reagent is selected from one or more in methyl alcohol, dimethylbenzene and 2-ethyl acid;
2) suspension film coating method deposit film on substrate or lampshade liner is adopted;
3) by step 2) thermal treatment 1 minute-10 minutes at the temperature of 380 DEG C-420 DEG C and in hydrogen atmosphere of obtained film, form the wideband gradient LED fluorescent film of 5 μm of-30 μm of thickness;
Method two is sol-gel method, and concrete steps are:
1) be that 1: 1 – 5 joins in silicon dioxide gel by wideband gradient LED fluorescent powder according to mass ratio, Homogeneous phase mixing, forms fluorescent material colloidal sol;
2) adopt dip-coating or spot printing mode plated film on substrate or lampshade liner, form wet gel diaphragm;
3) by step 2) diaphragm that dip-coating is good puts into loft drier, freeze-day with constant temperature 1-2h at 85 DEG C-95 DEG C;
4) diaphragm dried for step 3) is put into stoving oven and carry out roasting, should be more than first pre-burning stove to 60 DEG C before roasting; Then roasting be divided into two stages to carry out, the 1st stage constant temperature is at 300 DEG C-400 DEG C, and temperature rise rate is 1 DEG C/min-2 DEG C/min is incubated 0.5 – 1 hour; 2nd stage constant temperature is in 500 DEG C-600 DEG C, and temperature rise rate is 1 DEG C/min-2 DEG C/min, after reaching 500 DEG C-600 DEG C, and insulation 1h-3h, then naturally cooling cooling, forms the wideband gradient LED fluorescent film of 5 μm of-30 μm of thickness;
Wherein, method one is identical by crystalline structure successively from inside to outside with the individual particle of the gradient of wideband described in method two LED fluorescent powder and chemical composition the is different fluorescent substance of more than three layers forms; In the fluorescent substance of described more than three layers, the chemical formula of every one deck fluorescent substance is all selected from chemical formula 1, and described chemical formula 1 is: A 2.94-xb 5-yr yo 12: Ce 0.06+ Gd x, its 0≤x≤0.2,0≤y≤4, A is selected from Y, La or Pr; B and R is selected from Al respectively, Ga, In or Ti;
Or the chemical formula of every one deck fluorescent substance is all selected from chemical formula 2 in the fluorescent substance of described more than three layers, described chemical formula 2 is: D pe 2-pfO 4: Eu q, its 0 < p < 2,0.05 < q≤0.2, D and E is selected from Mg, Ca, Sr, or Ba; F is selected from C, Si, Ge, Sn or Pb.
In described wideband gradient LED fluorescent powder, typical example is: in the fluorescent substance of described more than three layers, the chemical formula of every one deck fluorescent substance is all selected from chemical formula 1 or is selected from chemical formula 2:
Chemical formula 1:Y 2.94-xal 5-yga yo 12: Ce 0.06+ Gd x, its 0≤x≤0.2,0≤y≤4(this be YAG:Ce series phosphor powder);
Chemical formula 2:Ba psr 2-psi O 4: Eu q, its 0 < p < 2,0.05 < q≤0.2(this be BSS:Eu series phosphor powder).
More typical example is: the individual particle of described fluorescent material is Y by chemical formula from inside to outside successively 2.94al 2.5ga 2.5o 12: Ce 0.06, Y 2.94al 5o 12: Ce 0.06and Y 2.74al 5o 12: Ce 0.06+ Gd 0.2three layers of fluorescent substance composition; Or be Y by chemical formula successively from inside to outside 2.74al 5o 12: Ce 0.06+ Gd 0.2, Y 2.94al 5o 12: Ce 0.06and Y 2.94al 2.5ga 2.5o 12: Ce 0.06three layers of fluorescent substance composition; Or be Ba by chemical formula successively from inside to outside 1.8sr 0.2siO 4: Eu 0.06, Ba 0.5sr 1.5siO 4: Eu 0.06and Ba 0.1sr 1.9siO 4: Eu 0.2three layers of fluorescent substance composition; Or be Ba by chemical formula successively from inside to outside 0.1sr 1.9siO 4: Eu 0.2, Ba 0.5sr 1.5siO 4: Eu 0.06and Ba 1.8sr 0.2siO 4: Eu 0.06three layers of fluorescent substance composition.
Wherein, the preparation method of wideband gradient LED fluorescent powder of the present invention, comprises the following steps:
(1) nano level and micro/nano level fluorescent material is prepared:
A) prepare burden: according to the chemical formula of target fluorescent powder, take the female salts solution of raw material according to mol ratio and prepare burden, obtain raw material mother liquor; Bicarbonate of ammonia and ammoniacal liquor are mixed with mother liquor of precipitation of ammonium, wherein control the starting point concentration of mother liquor of precipitation of ammonium between 1M/L ~ 6M/L, and the pH value controlling mother liquor of precipitation of ammonium is between 8 ~ 12;
B) prepare presoma mixed sediment: in excessive mother liquor of precipitation of ammonium, drip raw material mother liquor, dropping limit, limit is stirred, and makes it fully react, obtains reaction soln; Control the temperature of reaction soln between 20 DEG C ~ 70 DEG C, digestion time is 8-24 hour, and the pH value of reaction soln is between 8 ~ 12; Then in described reaction soln, add dispersion agent, the add-on of dispersion agent is the 0.5%-3% of reaction soln quality; After having reacted, by reaction soln through centrifugation, after filtration, washing, drying, obtain presoma mixed sediment;
C) oxidizing roasting: by presoma mixed sediment in oxidizing atmosphere or air at 890 DEG C-950 DEG C pre-burning 1-3 hour, until formed white powder, fine ground mistake 150 order-300 mesh sieve obtains white powder; White powder is calcined 1-6 hour in oxidizing atmosphere or air at 1000 DEG C ~ 1500 DEG C, at the temperature of 1000 DEG C ~ 1600 DEG C, 0.5-3 hour is sintered again under reducing atmosphere, through milled 200-300 mesh sieve or carry out air-flow or current classification after cooling, obtain the nano level fluorescent material of 10nm ~ 100nm and the micro/nano level fluorescent material of 100nm ~ 1000nm;
(2) be selected from one of following two kinds of methods and prepare micrometer fluorescent powder:
Method 1: the micro/nano level fluorescent material of 100nm ~ 1000nm above-mentioned steps (1) prepared continues the temperature lower calcination at 1000 DEG C ~ 1600 DEG C, obtains the micrometer fluorescent powder of size range at 1-5 micron;
Method 2: adopt high temperature solid-state method to prepare micrometer fluorescent powder, namely according to the chemical formula of target fluorescent powder, the starting oxides taking each component according to mol ratio is prepared burden, the powder choosing a kind of raw material is micron order, other raw materials and fusing assistant are nano level, lapped face activates, mixing, again at 1000 DEG C ~ 1750 DEG C according to the fusing point step sintering of fusing assistant, then reduce at 1400 DEG C ~ 1600 DEG C, grind again, pickling, screening, classification, obtain the micrometer fluorescent powder of size range at 1-10 micron; Fusing assistant adopts one of following compounds or their mixture, and fusing assistant accounts for the 1-5%:Li of fluorescent material weight 2cO 3, H 3bO 3, NaF, MgF 2, AlF 3, KF, CaF 2, CaCO 3, SrF 2, SrCl 2, SrCO 3, BaF;
(3) epitaxy: be selected from one of following two kinds of methods and carry out epitaxy:
Method 1: using the size range prepared by step (2) at the micrometer fluorescent powder of 1-5 micron as crystal seed, be epitaxy thing a with the micro/nano level fluorescent material of the nano level fluorescent material of the second 10nm ~ 100nm prepared by step (1) described method or 100nm ~ 1000nm, crystal seed is mixed with epitaxy thing a, obtain mixture A, wherein crystal seed accounts for the quality of mixture A is that 5%-30%(is preferably 8%-20%); By mixture A epitaxy 3-10 hour at the temperature of 1100 DEG C ~ 1700 DEG C, obtain intermediate, i.e. the epitaxially grown second layer; Be epitaxy thing b with the micro/nano level fluorescent material of the nano level fluorescent material of the third the 10nm ~ 100nm prepared by step (1) described method or 100nm ~ 1000nm again, intermediate is mixed with epitaxy thing b, obtain mixture B, wherein intermediate accounts for the quality of mixture B is that 5%-30%(is preferably 8%-20%); By mixture B epitaxy 3-10 hour at the temperature of 1100 DEG C ~ 1700 DEG C, obtain epitaxially grown third layer; Then grinding obtains identical by crystalline structure successively from inside to outside and chemical composition is different three layers of fluorescent substance form wideband gradient LED fluorescent powder; When preparing identical by the crystalline structure successively from inside to outside and wideband gradient LED fluorescent powder that chemical composition is different N layer fluorescent substance forms, the preparation method of n-th layer is identical with the preparation method of the epitaxially grown second layer or epitaxially grown third layer, and wherein said N is greater than 3 positive integers being less than 10;
Method 2: using the size range prepared by step (2) at the micrometer fluorescent powder of 1-5 micron as crystal seed, with the second fluorescent substance composition for target a) is prepared burden by step (1), prepare solution, crystal seed is joined in configured solution, by step (1) b) described in method precipitate, throw out is carried out centrifugation, after filtration, washing, drying, again in oxidizing atmosphere or air at 890 DEG C-950 DEG C pre-burning 1-3 hour, until formation white powder, fine ground mistake 150 order-300 mesh sieve obtains white powder; White powder is calcined 1-6 hour in oxidizing atmosphere or air at 1000 DEG C ~ 1500 DEG C, material, the i.e. epitaxially grown second layer after must calcining; Through milled 200-300 mesh sieve after the rear material cooling of calcining, be re-used as crystal seed with screen underflow; Again with the third fluorescent substance composition for target repeats the preparation process of the described epitaxially grown second layer, epitaxially grown third layer is obtained after calcining cooling, obtain identical by crystalline structure successively from inside to outside and chemical composition is different three layers of fluorescent substance forms wideband gradient LED fluorescent powder through grinding, the add-on of each crystal seed is that the 5%-30%(of calcining material mass is afterwards preferably 8%-20%) be as the criterion; When preparing identical by the crystalline structure successively from inside to outside and wideband gradient LED fluorescent powder that chemical composition is different N layer fluorescent substance forms, the preparation method of n-th layer is identical with the preparation method of epitaxially grown third layer, using the screen underflow of epitaxially grown N-1 layer as crystal seed, wherein said N is greater than 3 positive integers being less than 10.
Step (1) a) in the chemical formula of preferred described target fluorescent powder be Y 2.94-xal 5-yga yo 12: Ce 0.06+ Gd x, its 0≤x≤0.2, during 0≤y≤4, raw material is for containing Y 3+, Al 3+, Gd 3+, Ga 3+and Ce 3+female salts solution; When the chemical formula of target fluorescent powder is Ba psr 2-psiO 4: Eu q, during its 0 < p < 2,0.05 < q≤0.2, raw material is for containing Ba 2+, Sr 2+, Si 2+and Eu 3+female salts solution.
Step (1) a) in preferably take the method measuring powder the efficiency of formation to realize accurate feed proportioning.The method of concrete mensuration powder the efficiency of formation is shown in embodiment.
The b of step (1)) in preferably adopt microwave heating to control the temperature of reaction soln, temperature-controlled precision reaches ± 1.5 ~ 2 DEG C.
The b of step (1)) described in dispersion agent be preferably selected from polyoxyethylene glycol, tetraethoxy, polyvinyl alcohol, polyvinyl pyrrole gastral cavity ketone, propylene glycol, glycerol, ethanol, propyl alcohol, butanols and the alcohol of carbon atom within 5-10 wherein one or more.
The c of step (1)) described in reducing atmosphere preferably refer to the mixed gas be made up of nitrogen and hydrogen or the mixed gas be made up of argon gas and hydrogen, wherein the volume content of hydrogen is preferably 2%-20%.
Preferred employing dispersion agent carries out surface modification treatment, to improve dispersiveness to the nano level fluorescent material of 10nm ~ 100nm that step (2) obtains and the micro/nano level fluorescent material of 100nm ~ 1000nm; Described dispersion agent is selected from polyoxyethylene glycol, tetraethoxy, polyvinyl alcohol, polyvinyl pyrrole gastral cavity ketone, propylene glycol, glycerol, ethanol, propyl alcohol, butanols and the alcohol of carbon atom within 5-10 wherein one or more.
Described in preferred steps (3), crystal seed is Y 2.94al 2.5ga 2.5o 12: Ce 0.06, epitaxy thing a is Y 2.94al 5o 12: Ce 0.06, epitaxy thing b is Y 2.74al 5o 12: Ce 0.06+ Gd 0.2; Or described crystal seed is Y 2.74al 5o 12: Ce 0.06+ Gd 0.2, epitaxy thing a is Y 2.94al 5o 12: Ce 0.06, epitaxy thing b is Y 2.94al 2.5ga 2.5o 12: Ce 0.06; Or described crystal seed is Ba 1.8sr 0.2siO 4: Eu 0.06, epitaxy thing a is Ba 0.5sr 1.5siO 4: Eu 0.06, epitaxy thing b is Ba 0.1sr 1.9siO 4: Eu 0.2; Or described crystal seed is Ba 0.1sr 1.9siO 4: Eu 0.2, epitaxy thing a is Ba 0.5sr 1.5siO 4: Eu 0.06, epitaxy thing b is Ba 1.8sr 0.2siO 4: Eu 0.06.
The size-grade distribution of step (3) described wideband gradient LED fluorescent powder is between 0.5-120 micron.
Preferably step (3) described wideband gradient LED fluorescent powder is carried out grinding and air-flow or liquid stream stage treatment, obtain median size D 50respectively at 2 ~ 4 microns, 4 ~ 8 microns, 10 ~ 12 microns, 14 ~ 16 microns, 18 ~ 22 microns, the micron order wideband gradient fluorescent material of the different stage of 25 ~ 30 microns, and D 90/ D 50≤ 3.0.
Preferably surface modification treatment is carried out to micron order wideband gradient fluorescent material at different levels; Described dispersion agent is selected from polyoxyethylene glycol, tetraethoxy, polyvinyl alcohol, polyvinyl pyrrole gastral cavity ketone, propylene glycol, glycerol, ethanol, propyl alcohol, butanols and the alcohol of carbon atom within 5-10 wherein one or more.
More preferably step (3) described wideband gradient LED fluorescent powder is carried out grain composition, obtain the wideband gradient LED fluorescent powder after grating, wherein grading distribution scheme is:
Particle diameter is the 2%-5% that the particle of 30 nanometer-400 nanometers accounts for the wideband gradient LED fluorescent powder after grating,
Particle diameter is the 8%-15% that the particle of 400 nanometer-1500 nanometers accounts for the wideband gradient LED fluorescent powder after grating;
Particle diameter is the 80%-90% that the particle of 2 Wei meter – 80 microns accounts for the wideband gradient LED fluorescent powder after grating.
Further preferably, step (3) described wideband gradient LED fluorescent powder is carried out grain composition, and obtain the LED fluorescent powder after grating, wherein grading distribution scheme is:
Particle diameter is the 2%-5% that the particle of 100 nanometer-200 nanometers accounts for the LED fluorescent powder after grating,
Particle diameter is the 8%-15% that the particle of 900 nanometer-1500 nanometers accounts for the LED fluorescent powder after grating;
Particle diameter is the 80%-90% that the particle of 5 Wei meter – 20 microns accounts for the LED fluorescent powder after grating.
Further preferably, step (3) described wideband gradient LED fluorescent powder is carried out grain composition, and obtain the LED fluorescent powder after grating, wherein grading distribution scheme is:
Particle diameter is the 2%-5% that the particle of 200 nanometer-400 nanometers accounts for the LED fluorescent powder after grating,
Particle diameter is the 8%-15% that the particle of 900 nanometer-1500 nanometers accounts for the LED fluorescent powder after grating;
Particle diameter is the 80%-90% that the particle of 10 Wei meter – 35 microns accounts for the LED fluorescent powder after grating.
Further preferably, step (3) described wideband gradient LED fluorescent powder is carried out grain composition, and obtain the LED fluorescent powder after grating, wherein grading distribution scheme is:
Particle diameter is the 2%-5% that the particle of 200 nanometer-400 nanometers accounts for the LED fluorescent powder after grating,
Particle diameter is the 8%-15% that the particle of 900 nanometer-1500 nanometers accounts for the LED fluorescent powder after grating;
Particle diameter is the 80%-90% that the particle of 40 Wei meter – 80 microns accounts for the LED fluorescent powder after grating.
In addition, the preparation of silicon dioxide gel described in method two is preferably: first mix with the dehydrated alcohol of half and tetraethoxy, and second half ethanol and deionized water are mixed, stir 5-10min respectively simultaneously; Add dimethyl formamide after pouring two kinds of mixed solutions into same beaker again, then between adjust pH to 5-7, obtain silicon dioxide gel; Wherein the ratio of the amount of raw material is: n(tetraethoxy): n(dehydrated alcohol): n(deionized water): n(dimethyl formamide)=1: (1-4): (5-10): (0.2 – 0.4).
Below the present invention be further explained and illustrate:
1, the present invention realizes accurate feed proportioning by the mensuration of powder the efficiency of formation, and its principle is: such as the typical YAG:Ce yttrium aluminium garnet fluorescent powder series of preparation, separately to each component Al 3+, Y 3+, Gd 3+, Ga 3+and Ce 3+female salts solution carry out precipitating, dry and calcining experiment, measure the actual coefficient forming amount of powder, powder the efficiency of formation=reality forms amount of powder/theoretical value, formula value calculating when carrying out precipitation experiments with powder the efficiency of formation, formula value=theoretical value/powder the efficiency of formation, concrete with reference to embodiment.
2, the principle preparing presoma mixed sediment is: preferably adopt microwave heating precipitation from homogeneous solution technology, make reaction system thermally equivalent, accurate control temperature of reaction, temperature-controlled precision ± 1.5 ~ 2 ° C, solves the problem that temperature of reaction system is uneven, temperature fluctuation is large that previous methods exists.Required precipitation agent progressively, is controllably formed in system (by controlling the concentration of temperature of reaction system and each reactant in reaction process, mother liquor of precipitation of ammonium is made to generate hydroxide radical required for precipitin reaction and carbanion according to the speed hydrolysis of precipitin reaction), thus guarantee that precipitant concentration is even, precipitin reaction each position pH value is homogeneous, all the time control between 8 ~ 12, solve that the precipitation agent partial concn that conventional additional precipitation agent mode causes is too high, pH value is too high, precipitin reaction each position pH value differs greatly, homogeneity is poor, the problem that system concentration is uneven.
Microwave heating precipitation from homogeneous solution technology can obtain the mixed sediment (precursor, precursors) that composition, pattern and size-grade distribution accurately control, and lays the foundation for finally obtaining high-performance fluorescent material.
3, calcining, sintering and reducing, dispersion treatment
Sintering process under adopting the high-temperature calcination under oxidation alternately or air atmosphere and reducing atmosphere accurately to control, by being oxidized the carbon fully removed and exist in coprecipitation technology, and adopt sintering and reducing Technology accurately under reducing atmosphere, obtain required thing phase and valence state, the fluorescent powder of lattice perfection (as equal in rear-earth-doped YAG yttrium aluminum garnet thing phase or nitride, oxynitride thing), suppress the generation of by product (dephasign).Pure thing phase needed for formation and the nano level of rare earth element valence state, micro/nano level high-performance fluorescent material.
For dispersion agent, surface modified dispersion process is carried out to nano level, micro/nano level fluorescent material with polyoxyethylene glycol or tetraethoxy etc., obtain the powder of favorable dispersity, the coating effect had.
4, the preparation of micron order wideband gradient fluorescent material
Micron order is median size D particularly 50large grain size more than 10 microns has complete crystalline structure, the fluorescence property thus presented.The present invention adopts pure phase micrometer fluorescent powder crystal grain as crystal seed further, with different components and there is the pure phase nanometer level of identical crystalline structure, micro/nano level phosphor powder mixes mutually, under the high temperature of 1100-1700 ° of C, prepare pure phase wideband gradient micrometer fluorescent powder large grain size by epitaxy.Its grain-size is by the ratio of pure phase micrometer fluorescent powder and pure phase nanometer level, micro/nano level fluorescent material, and calcining temperature and time control.
5, the fluorescent material classification of micron order wideband gradient and surface modification
Specially designed pulverizing, the unique proprietary modification of fine grading and powder surface are carried out to micron order wideband gradient fluorescent material, obtains the wideband gradient fluorescent material product of adjustable controlled, the rational size distribution of median size and good dispersity, such as D 50from 2 to 35 microns (μm) compared with adjustable in broad range, D 90/ D 50≤ 3.0.Powder granule, by surperficial special modification technology (using polyoxyethylene glycol and tetraethoxy etc. as dispersion agent), makes wideband gradient fluorescent material keep good dispersiveness, guarantees good application effect.
6, grain composition
Fluorescent powder grain tap density determines the number of unit volume phosphor material powder, therefore, fluorescent material different for granular size is carried out the distribution that grating (mixing) can optimize fluorescent powder grain size, improve fluorescent powder grain tap density, thus strengthen the luminous efficiency of fluorescent material further, be also like this for wideband gradient fluorescent material.In addition, the luminous efficiency of fluorescent material is relevant with the scattering strength of incident exciting light.For blue light and ultraviolet LED, fluorescent powder grain size has the highest scattering strength when 500 – 900nm.According to calculating, low particle size is 100-200 nanometer (mass percentage 5-2%), median particle size is 500-900 nanometer (mass percentage 15-8%), large particle size is that 5 – 9 microns (mass percentage 80-90%) can form the highest fluorescent powder grain tap density and the highest scattering strength, is also like this for wideband gradient fluorescent material.
Compared with prior art, advantage of the present invention is:
1, this preparation method with a kind of wideband gradient LED fluorescent powder for raw material, adopt polychrome (RGB etc.) fluorescent material film of suspension method or sol-gel method depositing homogeneous on the led device or on LED lamp cover liner, the wideband gradient LED fluorescent film that the method is prepared has each to uniform colour temperature. can manufacture and produce in enormous quantities high performance White LED s simultaneously, and keep same performance, can prepare and there is high optoelectronic transformation efficiency and the high color rendering index (CRI) i.e. White LED devices of approximate sunlight.
2, wideband gradient LED fluorescent powder of the present invention has special gradient-structure and different chemical constitutions, good dispersity, lattice perfection, tap density are high, glow frequency is wider than general fluorescent material, scattering strength is large, and luminous efficiency is high, and preparation method is unique, batching is accurate, precipitation is even, temperature precise control, can suppress the generation of by product (dephasign).
3, the present invention adopts grain composition, improves fluorescent powder grain tap density, thus strengthens the luminous efficiency of fluorescent material further, thus prepares better fluorescence membrane.
Accompanying drawing explanation
Fig. 1 is a kind of structural representation of wideband gradient fluorescent material of the embodiment of the present invention 1;
Fig. 2 is the another kind of structural representation of wideband gradient fluorescent material of the embodiment of the present invention 1;
Fig. 3 is a kind of structural representation of wideband gradient fluorescent material of the embodiment of the present invention 2;
Fig. 4 is the another kind of structural representation of wideband gradient fluorescent material of the embodiment of the present invention 2;
Fig. 5 is preparation technology's schema of embodiment of the present invention 1YAG-A series wideband gradient fluorescent material;
Fig. 6 is preparation technology's schema of embodiment of the present invention 1YAG-B series wideband gradient fluorescent material;
Fig. 7 is preparation technology's schema of embodiment of the present invention 2BSS-A series wideband gradient fluorescent material;
Fig. 8 is preparation technology's schema of embodiment of the present invention 2BSS-B series wideband gradient fluorescent material;
Fig. 9 is embodiment of the present invention 1YAG powder XRD analysis result, presents the pure phase of YAG;
Figure 10 is the Electronic Speculum figure (1400 DEG C, 30000 times) of YAG nano level fluorescent material of the present invention;
Figure 11 is the Electronic Speculum figure (1500 DEG C, 30000 times) of YAG micro/nano level fluorescent material of the present invention;
Figure 12 is the Electronic Speculum figure (1550 DEG C, 30000 times) of YAG micro/nano level fluorescent material of the present invention
Figure 13 is the Electronic Speculum figure of YAG micron order large grain size fluorescent material of the present invention;
Figure 14 is the spectrogram of conventional blue-ray LED+yellow fluorescent powder synthesize white light;
Figure 15 is the YAG wideband gradient fluorescent material spectrogram that LED excites prepared by embodiment 1;
Figure 16 is the BSS wideband gradient fluorescent material spectrogram that LED excites prepared by embodiment 1;
Figure 17 is the nucleocapsid structure adopting crystal grain and liquid phase coprecipitation method to be formed;
Figure 18 is the plated film position relationship schematic diagram of plated film on LRD chip in embodiment 3 and 4;
Figure 19 is the plated film position relationship schematic diagram of plated film on lampshade in embodiment 3 and 4;
Figure 20 is the process flow sheet of suspension method plated film described in embodiment 3 and 4;
Figure 21 is the process flow sheet of sol-gel method plated film described in embodiment 3 and 4;
Wherein, in Figs. 1-4,1 is Y 2.74al 5o 12: Ce 0.06+ Gd 0.2, 2 is Y 2.94al 5o 12: Ce 0.06, 3 is Y 2.94al 2.5ga 2.5o 12: Ce 0.06, 4 is Ba 0.1sr 1.9siO 4: Eu 0.2, 5 is Ba 0.5sr 1.5siO 4: Eu 0.06, 6 is Ba 1.8sr 0.2siO 4: Eu 0.06;
In figure 18,7 is sapphire substrates, and 8 is excessive layers, and 9 is N-type gan, and 10 is quantum well, and 11 is P-type gan, and 12 is AL/Ti lamination bottom electrodes, and 13 is transparent conductive oxides, and 14 is polychrome wideband gradient fluorescence membranes, and 15 is Au/Ni lamination top electrodes;
In Figure 19,16 is LED seats, and 17 is LED chips, and 18 is gradient fluorescence membranes, and 19 is LED lamp cover.
Embodiment
Below in conjunction with the drawings and specific embodiments, the present invention is further supplemented and described
Example prepared by embodiment 1YAG series wideband gradient fluorescent material
1. raw material, reagent:
Yttrium oxide (Y 2o 3>=99.99%) or Yttrium trinitrate (Y (NO 3) 36H 2o>=99.99%); Cerous nitrate (Ce (NO) 36H 2o, analytical pure); Aluminum nitrate (Al (NO 3) 39H 2o, analytical pure); Gallium nitrate (Ga (NO 3) 39H 2o, analytical pure), Gadolinium trinitrate (Gd (NO 3) 36H 2o, analytical pure), concentrated nitric acid HNO 3, analytical pure; Dehydrated alcohol, C 2h 5oH, analytical pure; Distilled water H 2o; Bicarbonate of ammonia (NH 4hCO 3, analytical pure); Ammoniacal liquor (NH 3h 2o, analytical pure); Polyoxyethylene glycol (PEG1000)
2. experimental installation
Conventional glass instrument; Moisture eliminator; Pure water system; Full-automatic electronic analytical balance; Constant temperature blender with magnetic force; Electric heating constant temperature tank; PH acidometer; Vacuum filtration system (band nanometer scale ceramics filters and quantitative paper); Whizzer; Constant Temp. Oven; Agate grinds alms bowl; High-temperature gas Protection stove, normal working temperature reaches 1700 ° of C.Testing sieve extension set (150 orders, 200 orders, 325 orders, 400 orders, 500 orders, electricity shakes), Fume Hoods, gas shield glove box etc.
(3) the determination test scheme of powder the efficiency of formation
3. the mensuration of powder the efficiency of formation
3.1, test objective
Independent investigation Al, Y, Ga, the powder the efficiency of formation of Ce and Gd after precipitation, drying and calcining, is revised theoretical value when implementing co-precipitation and calculating material proportion, to ensure the formation of the accuracy that YAG forms and pure phase.
3.2, principle
Separately to Al, Y, the solution of Ga, Gd and Ce carries out precipitating, dry and calcining experiment, measures the actual coefficient=reality formation amount of powder/theoretical value forming amount of powder.Formula value=theoretical value/reality forms the coefficient of amount of powder.Be that example is described as follows with Al, Y, Ce:
3.2.1Al 2o 3powder the efficiency of formation
2Al(NO 3) 3·9H2O→Al 2O 3
2mol Al (NO 3) 39H2O is converted into 1mol Al 2o 3.Al (NO 3) 39H2O molar mass is 375.13, Al 2o 3molar mass is 101.96, if transformation efficiency is 100%, then and 750.26 grams of Al (NO 3) 39H2O should obtain 101.96 grams of Al after precipitation, drying and calcining 2o 3.
3.2.2Y 2o 3powder the efficiency of formation
2Y(NO 3) 3·6H 2O→Y 2O 3
2mol Y (NO 3) 36H 2o is converted into 1mol Y 2o 3.Y (NO 3) 36H 2o molar mass is 383.06, Y 2o 3molar mass is 225.81, if transformation efficiency is 100%, then and 766.12 grams of Y (NO 3) 36H 2o should obtain 225.81 grams of Y after precipitation, drying and calcining 2o 3.
3.2.3CeO 2powder the efficiency of formation
Ce(NO 3) 3·6H2O→CeO 2
In theory, 1mol Ce (NO 3) 36H2O is converted into 1mol CeO 2.Ce (NO 3) 36H2O molar mass is 434.25, CeO 2molar mass is 172.11, if transformation efficiency is 100%, then and 434.25 grams of Ce (NO 3) 36H2O should obtain 172.11 grams of CeO after precipitation, drying and calcining 2.
3.2.4Ce 2o 3powder the efficiency of formation
If after precipitation, drying and calcining, then through weak reducing atmosphere process, then Ce 4+be reduced to Ce 3+:
2Ce(NO 3) 3·6H2O→Ce 2O 3
In theory, 2mol Ce (NO 3) 36H2O is converted into 1mol Ce 2o 3.Ce (NO 3) 36H2O molar mass is 434.25, Ce 2o 3molar mass is 328.23, if transformation efficiency is 100%, then and 868.50 grams of Ce (NO 3) 36H2O should obtain 328.23 grams of Ce after precipitation, drying and calcining 2o 3.
By Al, Y, Ga, the mensuration of Ce and Gd powder the efficiency of formation, ensures the accuracy of YAG composition and the formation of pure phase, with the method batching and the fluorescent material being prepared into micro/nano level, the results are shown in Table 2, and carries out XRD analysis to it, the results are shown in Figure 9.Table 2 is composition test results of typical YAG:Ce plasma emission spectrum, proves the requirement reaching YAG:Ce composition, uses the method for measuring of above-mentioned powder the efficiency of formation to realize accurate feed proportioning.Fig. 9 is typical YAG powder XRD analysis result, presents the pure phase of YAG.
The composition test result of the typical YAG:Ce ion emission spectroscopy of table 2
4. wideband gradient fluorescent material process of preparing example:
Wideband gradient fluorescent material LED YAG – A, YAG-B series wideband gradient fluorescent material preparation technology is as shown in Figure 5 and Figure 6:
(1) nano level and micro/nano level fluorescent material is prepared:
A) prepare burden: according to the chemical formula of target fluorescent powder, take the female salts solution of raw material according to mol ratio and carry out prepare burden (taking the measuring method of above-mentioned powder the efficiency of formation to realize accurate feed proportioning), obtain raw material mother liquor; Bicarbonate of ammonia and ammoniacal liquor are mixed with mother liquor of precipitation of ammonium, and wherein control the starting point concentration of mother liquor of precipitation of ammonium between 1M/L ~ 6M/L, the present embodiment is 4M/L, and the pH value controlling mother liquor of precipitation of ammonium is between 8 ~ 12, and the present embodiment pH is 10;
B) prepare presoma mixed sediment: in excessive mother liquor of precipitation of ammonium, drip raw material mother liquor, dropping limit, limit is stirred, and makes it fully react, obtains reaction soln; Control the temperature of reaction soln between 50 ° of C ~ 60 ° C, temperature-controlled precision ± 1.5 ~ 2 ° C; Controlling the reaction times is 9 hours; The pH value controlling reaction soln is 10; Then in described reaction soln, add dispersion agent, the add-on of dispersion agent is 1.5% of reaction soln quality; After having reacted, will vacuum filtration be precipitated, and by distilled water, washing with alcohol, then be placed in Constant Temp. Oven 120 ~ 200 ° of C dryings, obtain YAG:Ce presoma;
C) oxidizing roasting: by the pre-burning 2 hours at 900 DEG C in oxidizing atmosphere or air of presoma mixed sediment, until form white powder, fine ground mistake 200 mesh sieve obtains white powder; White powder is calcined 4 hours in oxidizing atmosphere or air at 1100 DEG C, at the temperature of 1400 ° of C-1500 ° of C, 2 hours are sintered again under reducing atmosphere (5-20% hydrogen+all the other be nitrogen), through milled 200 mesh sieves or carry out air-flow or current classification after cooling, obtain the YAG:Ce nano level fluorescent material (its Electronic Speculum figure is shown in Figure 10) of 10nm ~ 100nm and the YAG:Ce micro/nano level fluorescent material (its Electronic Speculum figure is shown in Figure 11 and Figure 12) of 100nm ~ 1000nm;
To the detected result of the fluorescent material of above-mentioned YAG:Ce micro/nano level in table 2, and XRD analysis is carried out to it, the results are shown in Figure 9.Table 2 is composition test results of typical YAG:Ce plasma emission spectrum, proves the requirement reaching YAG:Ce composition, and proves to use the method for measuring of above-mentioned powder the efficiency of formation can realize accurate feed proportioning, decon.Fig. 9 is typical YAG powder XRD analysis result, presents the pure phase of YAG.
(2) be selected from one of following two kinds of methods and prepare micrometer fluorescent powder:
Method 1: the YAG:Ce micro/nano level fluorescent material of 100nm ~ 1000nm above-mentioned steps (1) prepared continues the temperature lower calcination at 1400 DEG C ~ 1600 DEG C, makes its grain growth, obtains size range mainly at the YAG:Ce micrometer fluorescent powder of 1-5 micron;
Method 2: adopt high temperature solid-state method to prepare micrometer fluorescent powder, namely according to the chemical formula of target fluorescent powder, the starting oxides taking each component according to mol ratio is prepared burden, the powder choosing a kind of raw material is micron order, other raw materials and fusing assistant are nano level, lapped face activates, mixing, again at 1000 DEG C ~ 1750 DEG C according to the fusing point step sintering of fusing assistant, then reduce at 1400 DEG C ~ 1600 DEG C, grind again, pickling, screening, classification, obtain the YAG:Ce micrometer fluorescent powder of size range at 1-10 micron; Fusing assistant adopts one of following compounds or their mixture, and fusing assistant accounts for the 1-5%:Li of fluorescent material weight 2cO 3, H 3bO 3, NaF, MgF 2, AlF 3, KF, CaF 2, CaCO 3, SrF 2, SrCl 2, SrCO 3, BaF;
(3) epitaxy:
Method 1: using the YAG:Ce micrometer fluorescent powder of the 1-5 micron prepared by step (2) as crystal seed, be epitaxy thing a with the micro/nano level fluorescent material of the nano level fluorescent material of the second 10nm ~ 100nm prepared by step (1) described method or 100nm ~ 1000nm, crystal seed is mixed with epitaxy thing a, obtain mixture A, wherein crystal seed accounts for the quality of mixture A is 15%; By mixture A epitaxy 3-10 hour at the temperature of 1100 DEG C ~ 1700 DEG C, obtain intermediate; Be epitaxy thing b with the micro/nano level fluorescent material of the nano level fluorescent material of the third the 10nm ~ 100nm prepared by step (1) described method or 100nm ~ 1000nm again, intermediate is mixed with epitaxy thing b, obtain mixture B, by mixture B epitaxy 3-10 hour at the temperature of 1100 DEG C ~ 1700 DEG C, obtain identical by crystalline structure successively from inside to outside and chemical composition is different three layers of fluorescent substance form wideband gradient LED fluorescent powder (its Electronic Speculum figure is shown in Figure 13).
Such as: by Y 2.94al 2.5ga 2.5o 12: Ce 0.06partially green nano level fluorescent material 1300-1600 ° of C high-temperature calcination technique, form pure phase micrometer fluorescent powder crystal grain.Then adopt pure phase micron order as consisted of Y 2.94al 2.5ga 2.5o 12: Ce 0.06inclined green fluorescence powder crystal grain as crystal seed, and there is from pure phase the yellow Y of same crystalline structure and different composition successively 2.94al 5o 12: Ce 0.06partially red Y 2.74al 5o 12: Ce 0.06+ Gd 0.2nano level phosphor powder mixes mutually, the greenish-yellow red YAG-A molded breadth of pure phase micron order high-level efficiency LED gradient fluorescent material single grain is frequently formed by substep epitaxy under the high temperature of 1500-1700 ° of C, as shown in Figure 1, it is identical by crystalline structure successively from inside to outside and chemical composition is different three layers of fluorescent substance form; I.e. " gradient " structure.
On the other hand, employing consists of partially red Y 2.74al 5o 12: Ce 0.06+ Gd 0.2nano level fluorescent material, further 1300-1600 ° of C high-temperature calcination technique, forms pure phase micrometer fluorescent powder crystal grain.Then pure phase micron order is adopted to consist of partially red Y 2.74al 5o 12: Ce 0.06+ Gd 0.2fluorescent material crystal grain as crystal seed, and has the yellow Y of same crystalline structure and different composition successively from pure phase 2.94al 5o 12: Ce 0.06partially green Y 2.94al 2.5ga 2.5o 12: Ce 0.06nano level phosphor powder mixes mutually, forms pure phase micron order high-level efficiency LED YAG-B type reddish yellow green wideband gradient fluorescent material single grain, as shown in Figure 2 under the high temperature of 1500-1700 ° of C by substep epitaxy.Its luminous intensity had and colour rendering index, as shown in figure 15; The spectrogram of blue-ray LED+yellow fluorescent powder synthesize white light of the prior art as shown in figure 14, contrasted from Figure 14 and Figure 15, the glow frequency of the fluorescent material prepared by the present invention is wider than the glow frequency of existing fluorescent material, and illumination effect is better, and white light is closer to natural light.
Method 2: with the YAG:Ce micrometer fluorescent powder of the 1-5 micron prepared by step (2) for crystal seed, with the second fluorescent substance composition for target a) is prepared burden by step (1), prepare solution, crystal seed is joined in configured solution, by step (1) b) described in method precipitate, throw out is carried out centrifugation, after filtration, washing, drying, again in oxidizing atmosphere or air at 890 DEG C-950 DEG C pre-burning 1-3 hour, until formation white powder, fine ground mistake 150 order-300 mesh sieve obtains white powder; White powder is calcined 1-6 hour in oxidizing atmosphere or air at 1000 DEG C ~ 1500 DEG C, material after must calcining, through milled 200-300 mesh sieve after the rear material cooling of calcining, be re-used as crystal seed with screen underflow; Again with the third fluorescent substance composition for target repeats the preparation process of described the second material, obtain identical by crystalline structure successively from inside to outside and chemical composition is different three layers of fluorescent substance forms wideband gradient LED fluorescent powder through grinding after calcining cooling, the add-on of each crystal seed is 5-30%(the present embodiment preferably 20% of the rear material mass of calcining) be as the criterion.
Such as: by Y 2.94al 2.5ga 2.5o 12: Ce 0.06partially green nano level fluorescent material 1300-1600 ° of C high-temperature calcination technique, form pure phase micrometer fluorescent powder crystal grain.Then adopt pure phase micron order as consisted of Y 2.94al 2.5ga 2.5o 12: Ce 0.06inclined green fluorescence powder crystal grain as crystal seed, and there is same crystalline structure successively and the yellow Y of the second of different composition from pure phase 2.94al 5o 12: Ce 0.06for target a) is prepared burden by step (1), prepare solution, crystal seed is joined in configured solution, by step (1) b) described in method precipitate, throw out is carried out centrifugation, filters, washing, after drying, then in oxidizing atmosphere or air at 890 DEG C-950 DEG C pre-burning 1-3 hour, until formation white powder, fine ground mistake 150 order-300 mesh sieve obtains white powder; White powder is calcined 1-6 hour in oxidizing atmosphere or air at 1000 DEG C ~ 1500 DEG C, material after must calcining, through milled 200-300 mesh sieve after the rear material cooling of calcining, be re-used as crystal seed with screen underflow; Again with the third partially red Y 2.74al 5o 12: Ce 0.06+ Gd 0.2fluorescent substance composition is the preparation process that target repeats described the second material, obtain through grinding the wideband gradient LED fluorescent powder that identical by crystalline structure successively from inside to outside and chemical composition different three layers and above fluorescent substance form after calcining cooling, the add-on of each crystal seed is the add-on of 5-30%(the present embodiment crystal seed of preferred first time of material mass after calcining is 20%, and the add-on of second time crystal seed is 15%).This monokaryon multiple layered shell fluorescent material presoma, the greenish-yellow red YAG-A molded breadth of pure phase micron order high-level efficiency LED gradient fluorescent material single grain is frequently formed by substep epitaxy under the high temperature of 1500-1700 ° of C, as shown in Figure 1, it is identical by crystalline structure successively from inside to outside and chemical composition is different three layers of fluorescent substance form; I.e. " gradient " structure.
On the other hand, employing consists of partially red Y 2.74al 5o 12: Ce 0.06+ Gd 0.2nano level fluorescent material, 1300-1600 ° of C high-temperature calcination technique, forms pure phase micrometer fluorescent powder crystal grain.Then adopt and consist of partially red Y 2.74al 5o 12: Ce 0.06+ Gd 0.2nano level fluorescent material crystal grain as crystal seed, and has same crystalline structure and the yellow Y of the second of different composition successively from pure phase 2.94al 5o 12: Ce 0.06for target a) is prepared burden by step (1), prepare solution, crystal seed is joined in configured solution, by step (1) b) described in method precipitate, throw out is carried out centrifugation, filters, washing, after drying, then in oxidizing atmosphere or air at 890 DEG C-950 DEG C pre-burning 1-3 hour, until formation white powder, fine ground mistake 150 order-300 mesh sieve obtains white powder; Form nucleocapsid structure as shown in figure 17.White powder is calcined 1-6 hour in oxidizing atmosphere or air at 1000 DEG C ~ 1500 DEG C, material after must calcining, through milled 200-300 mesh sieve after the rear material cooling of calcining, be re-used as crystal seed with screen underflow; Again with the third partially green Y 2.94al 2.5ga 2.5o 12: Ce 0.06fluorescent substance composition is the preparation process that target repeats described the second material, obtain through grinding the wideband gradient LED fluorescent powder that identical by crystalline structure successively from inside to outside and chemical composition different three layers and above fluorescent substance form after calcining cooling, the add-on of each crystal seed is the add-on of 5-30%(the present embodiment crystal seed of preferred first time of material mass after calcining is 20%, and the add-on of second time crystal seed is 15%).This monokaryon multiple layered shell fluorescent material presoma, this monokaryon multiple layered shell of pure phase micron order high-level efficiency LED fluorescent material presoma is formed by substep epitaxy under the high temperature of 1500-1700 ° of C, the green YAG-A molded breadth of pure phase micron order high-level efficiency LED reddish yellow gradient fluorescent material single grain is frequently formed by substep epitaxy under the high temperature of 1500-1700 ° of C, as shown in Figure 2, it is identical by crystalline structure successively from inside to outside and chemical composition is different three layers of fluorescent substance form; I.e. " gradient " structure.Its luminous intensity had and colour rendering index, as shown in figure 15; The spectrogram of blue-ray LED+yellow fluorescent powder synthesize white light of the prior art as shown in figure 14, contrasted from Figure 14 and Figure 15, the glow frequency of the fluorescent material prepared by the present invention is wider than the glow frequency of existing fluorescent material, and illumination effect is better, and white light is closer to natural light.
Unique high-temperature calcination under accurately being controlled by atmosphere, sintering process, obtain required thing phase, the fluorescent powder of lattice perfection (as equal in rear-earth-doped YAG yttrium aluminum garnet thing phase or nitride, oxynitride thing), suppress the generation of by product (dephasign); To obtain required thing phase and valence state.Pure thing phase needed for formation and valence state are the primary conditions obtaining high-performance fluorescent material.
The distribution of further optimization fluorescent powder grain size and grating, improve the luminous efficiency that fluorescent powder grain tap density can strengthen fluorescent material further.In addition, the luminous efficiency of fluorescent material is relevant with the scattering strength of incident exciting light.For blue light and ultraviolet LED, fluorescent powder grain size has the highest scattering strength when 500 – 900nm.According to calculating, following grating mode can form the highest fluorescent powder grain tap density and the highest scattering strength, specially designed pulverizing, the unique proprietary modification of fine grading and powder surface, obtain the fluorescent material of fine adjustable, the rational size distribution of particle diameter and good dispersity.
Particle diameter is the 2%-5% that the particle of 100 nanometer-200 nanometers accounts for the LED fluorescent powder after grating,
Particle diameter is the 8%-15% that the particle of 500 nanometer-900 nanometers accounts for the LED fluorescent powder after grating;
Particle diameter is the 80%-90% that the particle of 5 Wei meter – 9 microns accounts for the LED fluorescent powder after grating.
Embodiment 2:
BSS – A, BSS-B series wideband gradient fluorescent material preparation technology is as shown in Figure 7 and Figure 8:
1 raw material, reagent:
Barium oxide (BaO>=99.99%) or nitrate of baryta (Ba (NO 3) 2>=99.99%); Strontium oxide (SrO>=99.99%) or strontium nitrate (Sr (NO 3) 2>=99.99%); Europium nitrate (Eu (NO 3) 36H2O, analytical pure); Tetraethoxy (Si (OC 2h 5) 4, analytical pure); Concentrated nitric acid HNO 3, analytical pure; Dehydrated alcohol, C 2h 5oH, analytical pure; Distilled water H 2o; Bicarbonate of ammonia (NH 4hCO 3, analytical pure); Ammoniacal liquor (NH 3h 2o, analytical pure); Polyoxyethylene glycol (PEG1000)
2 experimental installations
Conventional glass instrument; Moisture eliminator; Pure water system; Full-automatic electronic analytical balance; Constant temperature blender with magnetic force; Electric heating constant temperature tank; PH acidometer; Vacuum filtration system (band nanometer scale ceramics filters and quantitative paper); Whizzer; Constant Temp. Oven; Agate grinds alms bowl; High-temperature gas Protection stove, normal working temperature reaches 1700 ° of C.Testing sieve extension set (325 orders, 400 orders, 500 orders, electricity shakes), Fume Hoods, gas shield glove box etc.
The determination test scheme of 3 powder the efficiency of formations
3.1, test objective
Independent investigation Ba, Sr, Si, the powder the efficiency of formation of Eu after precipitation, drying and calcining, is revised theoretical value when implementing co-precipitation and calculating material proportion, to ensure the formation of the accuracy that BSS forms and pure phase.
3.2, principle
Separately to Ba, Sr, Si, the solution of Eu carries out precipitating, dry and calcining experiment, measures the actual coefficient=reality formation amount of powder/theoretical value forming amount of powder.Formula value=theoretical value/reality forms the coefficient of amount of powder.
By Ba, Sr, Si, the mensuration of Eu powder the efficiency of formation, ensures the accuracy of BSS composition and the formation of pure phase.
The preparation of 4 high-level efficiency LED BSS-A, BSS-B series wideband gradient fluorescent material, concrete preparation method, with embodiment 1, just changes raw material.
Method 1: adopt pure phase micron order as consisted of Ba 1.8sr 0.2siO 4: Eu 0.06inclined green fluorescence powder crystal grain as crystal seed, and there is from pure phase the yellow Ba of same crystalline structure and different composition successively 0.5sr 1.5siO 4: Eu 0.06partially red Ba 0.1sr 1.9siO 4: Eu 0.2nano level phosphor powder mixes mutually, the greenish-yellow red BSS-A molded breadth of pure phase micron order high-level efficiency LED gradient fluorescent material single grain is frequently formed by substep epitaxy under the high temperature of 1500-1700 ° of C, as shown in Figure 3, it is identical by crystalline structure successively from inside to outside and chemical composition is different three layers of fluorescent substance form; I.e. " gradient " structure.
On the other hand, employing consists of partially red Ba 0.1sr 1.9siO 4: Eu 0.2nano level fluorescent material, adopts 1300-1600 ° of C high-temperature calcination technique further, forms pure phase micrometer fluorescent powder crystal grain.Then pure phase micron order is adopted to consist of partially red Ba 0.1sr 1.9siO 4: Eu 0.2fluorescent material crystal grain as crystal seed, and has the yellow Ba of same crystalline structure and different composition successively from pure phase 0.5sr 1.5siO 4: Eu 0.06partially green Ba 1.8sr 0.2siO 4: Eu 0.06nano level phosphor powder mixes mutually, pure phase micron order high-level efficiency LEDBSS-B type reddish yellow green wideband gradient fluorescent material single grain is formed by substep epitaxy under the high temperature of 1500-1700 ° of C, as shown in Figure 4, and the luminous intensity obtained and colour rendering index, as shown in figure 16.The spectrogram of blue-ray LED+yellow fluorescent powder synthesize white light of the prior art as shown in figure 14, contrasted from Figure 14 and Figure 16, the glow frequency of the fluorescent material prepared by the present invention is wider than the glow frequency of existing fluorescent material, and illumination effect is better, and white light is closer to natural light.
Its grain-size is by the ratio of pure phase micrometer fluorescent powder and pure phase nanometer level fluorescent material, and calcining temperature and time control.Unique high-temperature calcination under accurately being controlled by atmosphere, sintering process, obtain required thing phase, the fluorescent powder of lattice perfection, suppress the generation of by product (dephasign); To obtain required thing phase and valence state.Pure thing phase needed for formation and valence state are the primary conditions obtaining high-performance fluorescent material.
Method 2: identical with the preparation method of embodiment 1, with the BSS:Eu micrometer fluorescent powder of the 1-5 micron prepared by step (2) for crystal seed, with the second fluorescent substance composition for target a) is prepared burden by step (1), prepare solution, crystal seed is joined in configured solution, by step (1) b) described in method precipitate, throw out is carried out centrifugation, filter, washing, after drying, again in oxidizing atmosphere or air at 890 DEG C-950 DEG C pre-burning 1-3 hour, until formation white powder, fine ground mistake 150 order-300 mesh sieve obtains white powder, white powder is calcined 1-6 hour in oxidizing atmosphere or air at 1000 DEG C ~ 1500 DEG C, material after must calcining, through milled 200-300 mesh sieve after the rear material cooling of calcining, be re-used as crystal seed with screen underflow, again with the third fluorescent substance composition for target repeats the preparation process of described the second material, identical by crystalline structure successively from inside to outside and chemical composition is different three layers of fluorescent substance form wideband gradient LED fluorescent powder is obtained through grinding after calcining cooling, the add-on of each crystal seed is the add-on of 5-30%(the present embodiment crystal seed of preferred first time of material mass after calcining is 20%, and the add-on of second time crystal seed is 15%).
Such as: by Ba 1.8sr 0.2siO 4: Eu 0.06inclined green fluorescence powder carry out high-temperature calcination technique at 1300-1600 ° of C, form pure phase micrometer fluorescent powder crystal grain.Then adopt pure phase micron order as consisted of Ba 1.8sr 0.2siO 4: Eu 0.06inclined green fluorescence powder crystal grain as crystal seed, and there is same crystalline structure successively and the yellow Ba of the second of different composition from pure phase 0.5sr 1.5siO 4: Eu 0.06for target a) is prepared burden by step (1), prepare solution, crystal seed is joined in configured solution, by step (1) b) described in method precipitate, throw out is carried out centrifugation, filters, washing, after drying, then in oxidizing atmosphere or air at 890 DEG C-950 DEG C pre-burning 1-3 hour, until formation white powder, fine ground mistake 150 order-300 mesh sieve obtains white powder; White powder is calcined 1-6 hour in oxidizing atmosphere or air at 1000 DEG C ~ 1500 DEG C, material after must calcining, through milled 200-300 mesh sieve after the rear material cooling of calcining, be re-used as crystal seed with screen underflow; Again with the third partially red Ba 0.1sr 1.9siO 4: Eu 0.2fluorescent substance composition is the preparation process that target repeats described the second material, obtain through grinding the wideband gradient LED fluorescent powder that identical by crystalline structure successively from inside to outside and chemical composition different three layers and above fluorescent substance form after calcining cooling, the add-on of each crystal seed is the add-on of 5-30%(the present embodiment crystal seed of preferred first time of material mass after calcining is 20%, and the add-on of second time crystal seed is 15%).This monokaryon multiple layered shell fluorescent material presoma, the greenish-yellow red BSS-Eu-A molded breadth of pure phase micron order high-level efficiency LED gradient fluorescent material single grain is frequently formed by substep epitaxy under the high temperature of 1500-1700 ° of C, as shown in Figure 3, it is identical by crystalline structure successively from inside to outside and chemical composition is different three layers of fluorescent substance form; I.e. " gradient " structure.
On the other hand, employing consists of partially red Ba 0.1sr 1.9siO 4: Eu 0.2nano level fluorescent material, 1300-1600 ° of C high-temperature calcination technique, forms pure phase micrometer fluorescent powder crystal grain.Then adopt and consist of partially red Ba 0.1sr 1.9siO 4: Eu 0.2micro-scale crystal grain as crystal seed, and has same crystalline structure and the yellow Ba of the second of different composition successively from pure phase 0.5sr 1.5siO 4: Eu 0.06for target a) is prepared burden by step (1), prepare solution, crystal seed is joined in configured solution, by step (1) b) described in method precipitate, throw out is carried out centrifugation, filters, washing, after drying, then in oxidizing atmosphere or air at 890 DEG C-950 DEG C pre-burning 1-3 hour, until formation white powder, fine ground mistake 150 order-300 mesh sieve obtains white powder; White powder is calcined 1-6 hour in oxidizing atmosphere or air at 1000 DEG C ~ 1500 DEG C, material after must calcining, through milled 200-300 mesh sieve after the rear material cooling of calcining, be re-used as crystal seed with screen underflow; Again with the third partially green Ba 1.8sr 0.2siO 4: Eu 0.06fluorescent substance composition be the preparation process that target repeats described the second material, obtain through grinding the wideband gradient LED fluorescent powder that identical by crystalline structure successively from inside to outside and chemical composition different three layers and above fluorescent substance form after calcining cooling, the add-on of each crystal seed is the add-on of 5-30%(the present embodiment crystal seed of preferred first time of material mass after calcining is 20%, and the add-on of second time crystal seed is 15%).This monokaryon multiple layered shell fluorescent material presoma, this monokaryon multiple layered shell of pure phase micron order high-level efficiency LED fluorescent material presoma is formed by substep epitaxy under the high temperature of 1500-1700 ° of C, the green BSS-Eu-B molded breadth of pure phase micron order high-level efficiency LED reddish yellow gradient fluorescent material single grain is frequently formed by substep epitaxy under the high temperature of 1500-1700 ° of C, as shown in Figure 4, it is identical by crystalline structure successively from inside to outside and chemical composition is different three layers of fluorescent substance form; I.e. " gradient " structure.Its luminous intensity had and colour rendering index, as shown in figure 16; The spectrogram of blue-ray LED+yellow fluorescent powder synthesize white light of the prior art as shown in figure 14, contrasted from Figure 14 and Figure 16, the glow frequency of the fluorescent material prepared by the present invention is wider than the glow frequency of existing fluorescent material, and illumination effect is better, and white light is closer to natural light.
Specially designed pulverizing, the unique proprietary modification of fine grading and powder surface, obtain the fluorescent material product of fine adjustable, the rational size distribution of particle diameter and good dispersity, such as D 50from 2 to 30 microns compared with adjustable in broad range, D 90/ D 50≤ 3.0; Fine powder is the micro-nano powder surface special modification technology dispersiveness that makes fluorescent material keep good particularly.
The distribution of further optimization fluorescent powder grain size and grating, improve the luminous efficiency that fluorescent powder grain tap density can strengthen fluorescent material further.In addition, the luminous efficiency of fluorescent material is relevant with the scattering strength of incident exciting light.For blue light and ultraviolet LED, can the highest fluorescent powder grain tap density and the highest scattering strength be formed:
Particle diameter is the 2%-5% that the particle of 30 nanometer-400 nanometers accounts for the wideband gradient LED fluorescent powder after grating,
Particle diameter is the 8%-15% that the particle of 400 nanometer-1500 nanometers accounts for the wideband gradient LED fluorescent powder after grating;
Particle diameter is the 80%-90% that the particle of 2 Wei meter – 80 microns accounts for the wideband gradient LED fluorescent powder after grating.
The preparation method of embodiment 3:LED wideband fluorescence membrane, as shown in figure 18, can on LED chip direct plated film; As shown in figure 19, also can in LED lamp cover direct plated film.
1. prepare YAG line fluorescent thin-film technique flow process as shown in figure 20 with suspension method, concrete steps are as follows:
1.1 will pour into any one YAG series phosphor powder obtained in embodiment 1 in methyl alcohol (METHANOL) or dimethylbenzene (XYLENE) or 2-ethyl acid (2-ETHLHEXANOIC ACID) or their mixed solution, and forming mass concentration is the suspension of about 5%;
1.2 prepare YAG:Ce with described suspension 3+fluorescence membrane; Adopt suspension film coating method Direct precipitation YAG:Ce on LED chip or in LED lamp cover 3+fluorescence membrane;
1.3 will be obtained film dry, and in 380 ° of C-420 ° C and nitrogen atmosphere thermal treatment 1 minute-10 minutes to form the fine and close film of 5 – 30 μm.This thin-film material presents high efficiency phosphor material powder performance as shown in figure 15
2. prepare YAG line fluorescent thin-film technique flow process as shown in figure 21 with sol-gel process, concrete steps are as follows:
2.1 adopt raw material: tetraethoxy (TEOS, analytical pure); Dehydrated alcohol (EtOH, analytical pure); DMF (DMF, analytical pure); Concentrated hydrochloric acid (analytical pure), deionized water.
The preparation of 2.2 silicon dioxide gels: first mix with the dehydrated alcohol of half and tetraethoxy, second half ethanol and deionized water mixing, and with magnetic stirring apparatus, 5-10min is stirred to two kinds of mixed solutions, mixed solution adds a certain proportion of DMF after pouring same beaker into, then appropriate catalyzer (hydrochloric acid is added, pH value for regulator solution) pH value is between 5 – 7, prepare the ratio n(TEOS of the amount of substance of colloidal sol)/n(EtOH)/n(H2O)/n(DMF) be 1: 3: 6: 0.3.
The complete colloidal sol of preparation need be used magnetic stirrer 10-15min by 2.3, again any one YAG series phosphor powder obtained in embodiment 1 is added in colloidal sol, make it Homogeneous phase mixing, mass ratio is 1: 1, again by colloidal sol magnetic stirrer 10-20min complete for preparation, finally the colloidal sol mixed is parked certain hour in room temperature lower seal.
2.4 dip-coatings and spot printing mode plated film: stop 10s by after sol filming, colloidal sol is fully contacted with membrane surface, make colloidal sol be evenly coated in the outside surface of basement membrane, forms wet gel film.
2.5 thermal treatments: the diaphragm that dip-coating is good puts into loft drier, from 30 DEG C, be slowly warming up to 80 DEG C, at 80 DEG C of freeze-day with constant temperature 1-2h.Dried film pipe is put into stoving oven and carries out roasting, should first pre-burning stove to 60 DEG C before roasting.Then roasting is divided into two stages, the 1st stage constant temperature is at 400 DEG C, and temperature rise rate is 1 DEG C/min; Be incubated 1 hour, the 2nd stage constant temperature is in 600 DEG C, and temperature rise rate is 2 DEG C/min, and after reaching 600 DEG C, insulation 2h, then naturally cooling cooling, forms fine and close fluorescence membrane.
Embodiment 4:LED BSS:Eu 2+the preparation method of series wideband fluorescence membrane, as shown in figure 18, can on LED chip direct plated film; As shown in figure 19, also can in LED lamp cover direct plated film.
1, BSS:Eu is prepared with suspension method 2+as shown in figure 20, concrete steps are as follows in fluorescence membrane technical process:
1.1 BSS:Eu obtained by embodiment 2 2+fluorescent material is poured in methyl alcohol (METHANOL) or dimethylbenzene (XYLENE) or 2-ethyl acid (2-ETHLHEXANOIC ACID) or their mixed solution, and forming mass concentration is the suspension of 6%;
1.2 prepare BSS:Eu with described suspension 2+fluorescence membrane; Adopt suspension film coating method Direct precipitation BSS:Eu on LED chip or in LED lamp cover 2+fluorescence membrane;
1.3 will be obtained film dry, and in 380 ° of C-420 ° C and nitrogen atmosphere thermal treatment 1 minute-10 minutes to form the fine and close film of 5 – 30 μm.This thin-film material presents high efficiency phosphor material powder performance.
2. prepare BSS:Eu with sol-gel process 2+fluorescence membrane technical process as shown in figure 21, concrete steps with embodiment 3, just feed change any one BSS series LED fluorescent material prepared by embodiment 2.
2.1 adopt raw material: tetraethoxy (TEOS, analytical pure); Dehydrated alcohol (EtOH, analytical pure); DMF (DMF, analytical pure); Concentrated hydrochloric acid (analytical pure), deionized water.
The preparation of 2.2 silicon dioxide gels: first mix with the dehydrated alcohol of half and tetraethoxy, second half ethanol and deionized water mixing, and with magnetic stirring apparatus, 5-10min is stirred to two kinds of mixed solutions, mixed solution adds a certain proportion of DMF after pouring same beaker into, then appropriate catalyzer (hydrochloric acid is added, pH value for regulator solution) pH value is between 5 – 7, prepare the ratio n(TEOS of the amount of substance of colloidal sol)/n(EtOH)/n(H2O)/n(DMF) be 1: 2:5: 0.3.
The complete colloidal sol of preparation need be used magnetic stirrer 10-15min by 2.3, again any one BSS series LED fluorescent material obtained in embodiment 1 is added in colloidal sol, make it Homogeneous phase mixing, mass ratio is 1: 1 – 5, again by colloidal sol magnetic stirrer 10-20min complete for preparation, finally the colloidal sol mixed is parked certain hour in room temperature lower seal.
2.4 dip-coatings and spot printing mode plated film: stop 10s by after sol filming, colloidal sol is fully contacted with membrane surface, make colloidal sol be evenly coated in the outside surface of basement membrane, forms wet gel film.
2.5 thermal treatments: the diaphragm that dip-coating is good puts into loft drier, are slowly warming up to 80 DEG C from 30 DEG C, at 80 DEG C of freeze-day with constant temperature 1-2h.Dried film pipe is put into stoving oven and carries out roasting, should first pre-burning stove to 60 DEG C before roasting.Then roasting is divided into two stages, the 1st stage constant temperature is at-350 DEG C, and temperature rise rate is 2 DEG C/min; Be incubated 1 hour, the 2nd stage constant temperature is in 550 DEG C, and temperature rise rate is 2 DEG C/min, and after reaching 550 DEG C, insulation 2h, then naturally cooling cooling, forms fine and close fluorescence membrane.This thin-film material presents high efficiency phosphor material powder performance, as shown in figure 16.

Claims (16)

1. a preparation method for wideband gradient LED fluorescent film, is characterized in that, is selected from one of following two kinds of methods:
Method one is suspension method, and concrete steps are:
1) add in organic reagent by wideband gradient LED fluorescent powder, forming mass concentration is the suspension of 2%-10%; Described organic reagent is selected from one or more in methyl alcohol, dimethylbenzene and 2-ethyl acid;
2) suspension film coating method deposit film on LED substrate or lampshade liner is adopted;
3) by step 2) thermal treatment 1 minute-10 minutes at the temperature of 380 DEG C-420 DEG C and in hydrogen atmosphere of obtained film, form the wideband gradient LED fluorescent film of 5 μm of-30 μm of thickness;
Method two is sol-gel method, and concrete steps are:
1) be that 1: 1 – 5 joins in silicon dioxide gel by wideband gradient LED fluorescent powder according to mass ratio, Homogeneous phase mixing, forms fluorescent material colloidal sol;
2) adopt dip-coating or spot printing mode plated film on LED substrate or lampshade liner, form wet gel diaphragm;
3) by step 2) diaphragm that dip-coating is good puts into loft drier, freeze-day with constant temperature 1-2h at 85 DEG C-95 DEG C;
4) by step 3) dried diaphragm puts into stoving oven and carries out roasting, and should be more than first pre-burning stove to 60 DEG C before roasting; Then roasting be divided into two stages to carry out, the 1st stage constant temperature is at 300 DEG C-400 DEG C, and temperature rise rate is 1 DEG C/min-2 DEG C/min is incubated 0.5h-1h; 2nd stage constant temperature is in 500 DEG C-600 DEG C, and temperature rise rate is 1 DEG C/min-2 DEG C/min, after reaching 500 DEG C-600 DEG C, and insulation 1h-3h, then naturally cooling cooling, forms the wideband gradient LED fluorescent film of 5 μm of-30 μm of thickness;
Wherein, method one is identical by crystalline structure successively from inside to outside with the individual particle of the gradient of wideband described in method two LED fluorescent powder and chemical composition the is different fluorescent substance of more than three layers forms; In the fluorescent substance of described more than three layers, the chemical formula of every one deck fluorescent substance is all selected from chemical formula 1, and described chemical formula 1 is: A 2.94-xb 5-yr yo 12: Ce 0.06+ Gd x, its 0≤x≤0.2,0≤y≤4, A is selected from Y, La or Pr; B and R is selected from Al respectively, Ga, In or Ti;
Or the chemical formula of every one deck fluorescent substance is all selected from chemical formula 2 in the fluorescent substance of described more than three layers, described chemical formula 2 is: D pe 2-pfO 4: Eu q, its 0 < p < 2,0.05 < q≤0.2, D and E is selected from Mg, Ca, Sr, or Ba; F is selected from C, Si, Ge, Sn or Pb;
The preparation method of described wideband gradient LED fluorescent powder comprises the following steps:
(1) nano level and micro/nano level fluorescent material is prepared:
A) prepare burden: according to the chemical formula of target fluorescent powder, take the female salts solution of raw material according to mol ratio and prepare burden, obtain raw material mother liquor; Bicarbonate of ammonia and ammoniacal liquor are mixed with mother liquor of precipitation of ammonium, wherein control the starting point concentration of mother liquor of precipitation of ammonium between 1M/L ~ 6M/L, and the pH value controlling mother liquor of precipitation of ammonium is between 8 ~ 12;
B) prepare presoma mixed sediment: in excessive mother liquor of precipitation of ammonium, drip raw material mother liquor, dropping limit, limit is stirred, and makes it fully react, obtains reaction soln; Control the temperature of reaction soln between 20 DEG C ~ 70 DEG C, digestion time is 8-24 hour, and the pH value of reaction soln is between 8 ~ 12; Then in described reaction soln, add dispersion agent, the add-on of dispersion agent is the 0.5%-3% of reaction soln quality; After having reacted, by reaction soln through centrifugation, after filtration, washing, drying, obtain presoma mixed sediment;
C) oxidizing roasting: by presoma mixed sediment in oxidizing atmosphere or air at 890 DEG C-950 DEG C pre-burning 1-3 hour, until formed white powder, fine ground mistake 150 order-300 mesh sieve obtains white powder; White powder is calcined 1-6 hour in oxidizing atmosphere or air at 1000 DEG C ~ 1500 DEG C, at the temperature of 1000 DEG C ~ 1600 DEG C, 0.5-3 hour is sintered again under reducing atmosphere, through milled 200-300 mesh sieve or carry out air-flow or current classification after cooling, obtain the nano level fluorescent material of 10nm ~ 100nm and the micro/nano level fluorescent material of 100nm ~ 1000nm;
(2) be selected from one of following two kinds of methods and prepare micrometer fluorescent powder:
Method 1: the micro/nano level fluorescent material of 100nm ~ 1000nm above-mentioned steps (1) prepared continues the temperature lower calcination at 1000 DEG C ~ 1600 DEG C, obtains the micrometer fluorescent powder of size range at 1-5 micron;
Method 2: adopt high temperature solid-state method to prepare micrometer fluorescent powder, namely according to the chemical formula of target fluorescent powder, the starting oxides taking each component according to mol ratio is prepared burden, the powder choosing a kind of raw material is micron order, other raw materials and fusing assistant are nano level, lapped face activates, mixing, again at 1000 DEG C ~ 1750 DEG C according to the fusing point step sintering of fusing assistant, then reduce at 1400 DEG C ~ 1600 DEG C, grind again, pickling, screening, classification, obtain the micrometer fluorescent powder of size range at 1-10 micron; Fusing assistant adopts one of following compounds or their mixture, and fusing assistant accounts for the 1-5%:Li of fluorescent material weight 2cO 3, H 3bO 3, NaF, MgF 2, AlF 3, KF, CaF 2, CaCO 3, SrF 2, SrCl 2, SrCO 3, BaF;
(3) epitaxy: be selected from one of following two kinds of methods and carry out epitaxy:
Method 1: using the size range prepared by step (2) at the micrometer fluorescent powder of 1-5 micron as crystal seed, be epitaxy thing a with the micro/nano level fluorescent material of the nano level fluorescent material of the second 10nm ~ 100nm prepared by step (1) described method or 100nm ~ 1000nm, crystal seed is mixed with epitaxy thing a, obtain mixture A, wherein crystal seed accounts for the quality of mixture A is 5%-30%; By mixture A epitaxy 3-10 hour at the temperature of 1100 DEG C ~ 1700 DEG C, obtain intermediate, i.e. the epitaxially grown second layer; Be epitaxy thing b with the micro/nano level fluorescent material of the nano level fluorescent material of the third the 10nm ~ 100nm prepared by step (1) described method or 100nm ~ 1000nm again, intermediate is mixed with epitaxy thing b, obtain mixture B, wherein intermediate accounts for the quality of mixture B is 5%-30%; By mixture B epitaxy 3-10 hour at the temperature of 1100 DEG C ~ 1700 DEG C, obtain epitaxially grown third layer; Then grinding obtains identical by crystalline structure successively from inside to outside and chemical composition is different three layers of fluorescent substance form wideband gradient LED fluorescent powder; When preparing identical by the crystalline structure successively from inside to outside and wideband gradient LED fluorescent powder that chemical composition is different N layer fluorescent substance forms, the preparation method of n-th layer is identical with the preparation method of the epitaxially grown second layer or epitaxially grown third layer, and wherein said N is greater than 3 positive integers being less than 10;
Method 2: using the size range prepared by step (2) at the micrometer fluorescent powder of 1-5 micron as crystal seed, with the second fluorescent substance composition for target a) is prepared burden by step (1), prepare solution, crystal seed is joined in configured solution, by step (1) b) described in method precipitate, throw out is carried out centrifugation, after filtration, washing, drying, again in oxidizing atmosphere or air at 890 DEG C-950 DEG C pre-burning 1-3 hour, until formation white powder, fine ground mistake 150 order-300 mesh sieve obtains white powder; White powder is calcined 1-6 hour in oxidizing atmosphere or air at 1000 DEG C ~ 1500 DEG C, material, the i.e. epitaxially grown second layer after must calcining; Through milled 200-300 mesh sieve after the rear material cooling of calcining, be re-used as crystal seed with screen underflow; Again with the third fluorescent substance composition for target repeats the preparation process of the described epitaxially grown second layer, epitaxially grown third layer is obtained after calcining cooling, obtain identical by crystalline structure successively from inside to outside and chemical composition is different three layers of fluorescent substance forms wideband gradient LED fluorescent powder through grinding, the add-on of each crystal seed is that the 5%-30% of calcining material mass is afterwards as the criterion; When preparing identical by the crystalline structure successively from inside to outside and wideband gradient LED fluorescent powder that chemical composition is different N layer fluorescent substance forms, the preparation method of n-th layer is identical with the preparation method of epitaxially grown third layer, using the screen underflow of epitaxially grown N-1 layer as crystal seed, wherein said N is greater than 3 positive integers being less than 10.
2. the preparation method of wideband gradient LED fluorescent film according to claim 1, it is characterized in that, in the fluorescent substance of more than three layers described in wideband gradient LED fluorescent powder described in method one and method two, the chemical formula of every one deck fluorescent substance is all selected from chemical formula 1 or is selected from chemical formula 2:
Chemical formula 1:Y 2.94-xal 5-yga yo 12: Ce 0.06+ Gd x, its 0≤x≤0.2,0≤y≤4;
Chemical formula 2:Ba psr 2-psiO 4: Eu q, its 0 < p < 2,0.05 < q≤0.2.
3. the preparation method of wideband gradient LED fluorescent film according to claim 2, is characterized in that, the individual particle of fluorescent material described in wideband gradient LED fluorescent powder described in method one and method two is Y by chemical formula from inside to outside successively 2.94al 2.5ga 2.5o 12: Ce 0.06, Y 2.94al 5o 12: Ce 0.06and Y 2.74al 5o 12: Ce 0.06+ Gd 0.2three layers of fluorescent substance composition; Or be Y by chemical formula successively from inside to outside 2.74al 5o 12: Ce 0.06+ Gd 0.2, Y 2.94al 5o 12: Ce 0.06and Y 2.94al 2.5ga 2.5o 12: Ce 0.06three layers of fluorescent substance composition; Or be Ba by chemical formula successively from inside to outside 1.8sr 0.2siO 4: Eu 0.06, Ba 0.5sr 1.5siO 4: Eu 0.06and Ba 0.1sr 1.9siO 4: Eu 0.2three layers of fluorescent substance composition; Or be Ba by chemical formula successively from inside to outside 0.1sr 1.9siO 4: Eu 0.2, Ba 0.5sr 1.5siO 4: Eu 0.06and Ba 1.8sr 0.2siO 4: Eu 0.06three layers of fluorescent substance composition.
4. the preparation method of wideband gradient LED fluorescent film according to claim 1, is characterized in that, in the preparation method of wideband gradient LED fluorescent powder described in method one and method two step (1) a) described in the chemical formula of target fluorescent powder be Y 2.94-xal 5-yga yo 12: Ce 0.06+ Gd x, its 0≤x≤0.2, during 0≤y≤4, raw material is for containing Y 3+, Al 3+, Gd 3+, Ga 3+and Ce 3+female salts solution; When the chemical formula of target fluorescent powder is Ba psr 2-psiO 4: Eu q, during its 0 < p < 2,0.05 < q≤0.2, raw material is for containing Ba 2+, Sr 2+, Si 2+and Eu 3+female salts solution.
5. the preparation method of wideband gradient LED fluorescent film according to claim 1 or 4, it is characterized in that, in the preparation method of wideband gradient LED fluorescent powder described in method one and method two step (1) a) in take the method measuring powder the efficiency of formation to realize accurate feed proportioning.
6. the preparation method of wideband gradient LED fluorescent film according to claim 1 or 4, it is characterized in that, the b of step (1) in the preparation method of wideband gradient LED fluorescent powder described in method one and method two) in adopt microwave heating to control the temperature of reaction soln, temperature-controlled precision ± 1.5 ~ 2 DEG C.
7. the preparation method of wideband gradient LED fluorescent film according to claim 1 or 4, it is characterized in that, the b of step (1) in the preparation method of wideband gradient LED fluorescent powder described in method one and method two) described in dispersion agent be selected from polyoxyethylene glycol, tetraethoxy, polyvinyl alcohol, polyvinyl pyrrole gastral cavity ketone, propylene glycol, propylene glycol, glycerol, ethanol, propyl alcohol, butanols and the alcohol of carbon atom within 5-10 wherein one or more.
8. the preparation method of wideband gradient LED fluorescent film according to claim 1 or 4, it is characterized in that, the c of step (1) in the preparation method of wideband gradient LED fluorescent powder described in method one and method two) described in reducing atmosphere refer to the mixed gas be made up of nitrogen and hydrogen or the mixed gas be made up of argon gas and hydrogen, wherein the volume content of hydrogen is 2%-20%.
9. the preparation method of wideband gradient LED fluorescent film according to claim 1 or 4, it is characterized in that, in the preparation method of wideband gradient LED fluorescent powder described in method one and method two, adopt dispersion agent to carry out surface modification treatment to the nano level fluorescent material of 10nm ~ 100nm that step (2) obtains and the micro/nano level fluorescent material of 100nm ~ 1000nm; Described dispersion agent is selected from polyoxyethylene glycol, tetraethoxy, polyvinyl alcohol, polyvinyl pyrrole gastral cavity ketone, propylene glycol, glycerol, ethanol, propyl alcohol, butanols and the alcohol of carbon atom within 5-10 wherein one or more.
10. the preparation method of wideband gradient LED fluorescent film according to claim 1 or 4, is characterized in that, in the preparation method of wideband gradient LED fluorescent powder described in method one and method two, described in step (3) method 1, crystal seed is Y 2.94al 2.5ga 2.5o 12: Ce 0.06, epitaxy thing a is Y 2.94al 5o 12: Ce 0.06, epitaxy thing b is Y 2.74al 5o 12: Ce 0.06+ Gd 0.2; Or described crystal seed is Y 2.74al 5o 12: Ce 0.06+ Gd 0.2, epitaxy thing a is Y 2.94al 5o 12: Ce 0.06, epitaxy thing b is Y 2.94al 2.5ga 2.5o 12: Ce 0.06; Or described crystal seed is Ba 1.8sr 0.2siO 4: Eu 0.06, epitaxy thing a is Ba 0.5sr 1.5siO 4: Eu 0.06, epitaxy thing b is Ba 0.1sr 1.9siO 4: Eu 0.2; Or described crystal seed is Ba 0.1sr 1.9siO 4: Eu 0.2, epitaxy thing a is Ba 0.5sr 1.5siO 4: Eu 0.06, epitaxy thing b is Ba 1.8sr 0.2siO 4: Eu 0.06.
11. according to claim 1 or 4 preparation method of wideband gradient LED fluorescent film, it is characterized in that, in the preparation method of wideband gradient LED fluorescent powder described in method one and method two, the size-grade distribution of step (3) described wideband gradient LED fluorescent powder is between 0.5-120 micron.
12. according to claim 1 or 4 preparation method of wideband gradient LED fluorescent film, it is characterized in that, in the preparation method of wideband gradient LED fluorescent powder described in method one and method two, step (3) described wideband gradient LED fluorescent powder is carried out grinding and air-flow or liquid stream stage treatment, and with dispersion agent, surface modification treatment is carried out to micron order wideband gradient fluorescent material at different levels, obtain median size D 50respectively at 2 ~ 4 microns, 4 ~ 8 microns, 10 ~ 12 microns, 14 ~ 16 microns, 18 ~ 22 microns, the micron order wideband gradient fluorescent material of the different stage of 25 ~ 30 microns, and D 90/ D 50≤ 3.0.
13., according to the preparation method of wideband gradient LED fluorescent film described in claim 12, carry out surface modification treatment with dispersion agent to micron order wideband gradient fluorescent material at different levels; It is characterized in that, described dispersion agent is selected from polyoxyethylene glycol, tetraethoxy, polyvinyl alcohol, polyvinyl pyrrole gastral cavity ketone, propylene glycol, glycerol, ethanol, propyl alcohol, butanols and the alcohol of carbon atom within 5-10 wherein one or more.
14. according to claim 1 or 4 preparation method of wideband gradient LED fluorescent film, it is characterized in that, in the preparation method of wideband gradient LED fluorescent powder described in method one and method two, step (3) described wideband gradient LED fluorescent powder is carried out grain composition, obtain the wideband gradient LED fluorescent powder after grating, wherein grading distribution scheme is:
Particle diameter is the 2%-5% that the particle of 30 nanometer-400 nanometers accounts for the wideband gradient LED fluorescent powder after grating,
Particle diameter is the 8%-15% that the particle of 400 nanometer-1500 nanometers accounts for the wideband gradient LED fluorescent powder after grating;
Particle diameter is the 80%-90% that the particle of 2 Wei meter – 80 microns accounts for the wideband gradient LED fluorescent powder after grating.
15. according to the preparation method of wideband gradient LED fluorescent film described in claim 14, it is characterized in that, in the preparation method of wideband gradient LED fluorescent powder described in method one and method two, step (3) described wideband gradient LED fluorescent powder is carried out grain composition, obtain the LED fluorescent powder after grating, wherein grading distribution scheme is:
Particle diameter is the 2%-5% that the particle of 100 nanometer-200 nanometers accounts for the LED fluorescent powder after grating,
Particle diameter is the 8%-15% that the particle of 900 nanometer-1500 nanometers accounts for the LED fluorescent powder after grating;
Particle diameter is the 80%-90% that the particle of 5 Wei meter – 20 microns accounts for the LED fluorescent powder after grating.
The preparation method of 16. wideband gradient LED fluorescent film according to claim 1, it is characterized in that, being prepared as of silicon dioxide gel described in method two: first mix with the dehydrated alcohol of half and tetraethoxy, and by second half ethanol and deionized water mixing, stir 5-10min respectively simultaneously; Add dimethyl formamide after pouring two kinds of mixed solutions into same beaker again, then between adjust pH to 5 – 7, obtain silicon dioxide gel; Wherein the ratio of the amount of raw material is: n (tetraethoxy): n (dehydrated alcohol): n (deionized water): n (dimethyl formamide)=1: (1-4): (5-10): (0.2 – 0.4).
CN201310178877.5A 2013-05-15 2013-05-15 Preparation method of broadband gradient LED (Light-emitting Diode) fluorescent film Expired - Fee Related CN103243318B (en)

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CN107794034A (en) * 2017-04-20 2018-03-13 湖南省科学技术研究开发院 A kind of preparation method of single crystal grain wideband gradient LED fluorescent powder
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