CN100489055C - Fluorescent material for converting ultraviolet light into red light and its production - Google Patents

Abstract

A fluorescent material for converting ultraviolet into infrared ray at 200-300nm and its production are disclosed. It adopts Ca3Al206 as substrate and rare-earth metal ion RE as activator, which is selected from any one of Ce3+, Pr3+, Sm3+, Eu3+, Eu2+, Tb3+, Dy3+ and Yb3+. The process is carried out by preparing (Ca3-xA12REx(OH)10)X2+x by co-deposition method, and calcining at inactive gas, oxide or reducing atmosphere at 1000-1500degree to obtain the final fluorescent material. It is excited by ultraviolet 260nm to give out yellow light with maximum wavelength 614nm.

Description

UV-light is changed into fluorescent material of red light and preparation method thereof

Technical field

The present invention relates to a kind ofly wavelength to be changed into the embedded photoluminescent material (or claim fluorescent material) of red light in 200 to 300nm ultraviolet rays, belong to the technical field of embedded photoluminescent material.

Background technology

Searching effectively absorbs UV-light and converts visible light to and the stable inorganic rare earth fluorescent material of physical and chemical performance is the important directions of current research.For example, Eu ³⁺Adulterated YVO ₄, Y ₂O ₃, Y ₂O ₂Red illuminating materials such as S have been widely used in various colored demonstrations and lighting field.Explore new rare earth luminescent material, choice of base is extremely important.This patent is reported a kind of promising novel light-emitting substrate material---Ca ₃Al ₂O ₆Be a kind of substrate material to red (outward) optical transparency, relevant research does not appear in the newspapers.

Effect fluorescent material relatively good, that obtain commercial applications has red Y at present ₂O ₃: Eu, (Y, Gd) BO ₃: Eu etc., their fluorescence quantum efficiency is all than higher, more than 1.0 in similar fluorescent material.But these fluorescent materials also exist such-and-such problem in actual applications.For example, Y ₂O ₃: Eu ³⁺Be the highest fluorescent material of price, and brightness is not enough always; Red fluorescence material (Y, Gd) BO ₃: Eu ³⁺, down have high luminous intensity vacuum ultraviolet exciting, be the first-selection of PDP with red fluorescence material, but its luminous mainly be Eu ³⁺Magnetic dipole transition, main emission wavelength is ⁵D ₀→ ⁷F ₁The 593nm of transition emission, purity of color is lower than the NTSC standard.Because the purity of color of fluorescent material is the leading indicator that influences the panchromatic demonstration of image, therefore, the purity of color that improves red fluorescence material becomes one of key of improving its quality.

The Preparation of Fluorescent Material method is a lot, for example high temperature solid-state method, hydrothermal synthesis method, combustion synthesis method, sol-gel method and microwave radiation synthesis method or the like.These methods cut both ways, and only are suitable for the synthetic of some product.For example, solid state reaction (Solid-state Reaction) is one of method of often using, but its temperature of reaction is too high, and reaction conditions is relatively harsher.When the temperature of reactor skewness, be difficult to obtain to form and the uniform mutually product of thing; Simultaneously,, satisfactory dusty material be obtained, just ball milling must be carried out because the hardness of products therefrom is big.Do not only consuming time like this but also power consumption, ball milling may destroy the crystal habit of fluorescent material to a certain extent simultaneously, causes behind the ball milling luminosity of product seriously to be decayed; In addition, high temperature reaction is down introduced foreign ion from reaction vessel easily, and some activator ion also has volatility (as pb ²⁺Ion), cause luminosity to reduce.Therefore the novel synthesis of seeking to overcome above-mentioned weakness also is the important content of scientific effort.

The invention provides a kind of layered hydroxide (layered double hydroxides) precursor that obtains from coprecipitation method and prepare the method for fluorescent material, the material that is obtained by it is more loose, be easy to pulverize, and material is formed evenly.

Summary of the invention

Technical problem: the purpose of this invention is to provide a kind of mainly by the tricalcium aluminate of cheapness constitute, loose and to ruddiness and infrared light transparent, UV-light can be converted to fluorescent material of coloured visible light and preparation method thereof.

Technical scheme: the fluorescent material Ca that UV-light can be changed into coloured visible light of the present invention ₃Al ₂O ₆: RE is with tricalcium aluminate Ca ₃Al ₂O ₆Be matrix, rare earth ion RE is an activator, and chemical formula generally can be expressed as Ca ₃Al ₂O ₆: RE.In it was formed, Ca, Al atom number ratio may be a little less than 3:2, and described rare earth ion activator RE is Ce ³⁺, Pr ³⁺, Sm ³⁺, Eu ³⁺, Eu ²⁺, Tb ³⁺, Dy ³⁺, Yb ³⁺A kind of in the ion.

The preparation method is as follows:

1) at first use coprecipitation method to prepare a kind of layered hydroxide precursor [Ca that contains the indefinite crystal water of quantity _3-xAl ₂RE _x(OH) ₁₀] X _2+xThe x span is 0.001～0.3; RE is Ce ³⁺, Pr ³⁺, Sm ³⁺, Eu ³⁺, Tb ³⁺, Dy ³⁺, Yb ³⁺A kind of in the ion; X is a kind of negatively charged ion or several anionic mixture,

2) under 1000～1500 ℃ of temperature in inertia, oxidisability or reducing atmosphere the above-mentioned precursor of roasting can obtain fluorescent material Ca ₃Al ₂O ₆: RE.

Negatively charged ion can be NO ₃ ^-, Cl ^-, SO ₄ ^2-, CO ₃ ^2-, ClO ₄ ^-, one or more of acetate.

The preparation method of layered hydroxide precursor is:

1) preparation hybrid metal salt brine solution: press Ca ²⁺, Al ³⁺, RE ³⁺Molar fraction be respectively Ca ²⁺: 0.4～0.7; Al ³⁺: 0.6～0.3; RE ³⁺: 0.005～0.05 ratio takes by weighing raw material; If RE ³⁺Raw material is an oxide compound, then earlier it is dissolved in the nitric acid, is made into RE ³⁺Nitrate solution, will contain Ca then ²⁺, Al ³⁺Raw material add above-mentioned solution, promptly get the hybrid metal salt brine solution;

2) preparation alkali aqueous solution: being equivalent to Ca respectively ²⁺, Al ³⁺, RE ³⁺NaOH that total mole number is 1.5～2.3 times and NaNO ₃Soluble in water, promptly get alkali aqueous solution;

3) slowly add at the following alkaline solution of violent stirring and be equipped with in the reactor of hybrid metal salt brine solution, control reaction temperature is that the pH value of final blending reaction solution is 7～10 between the room temperature to 120 ℃; The suspension that obtains continued stirring reaction 24 hours, filtered then, washing, vacuum-drying get final product.

Among the preparation method of layered hydroxide precursor, the hybrid metal salt brine solution can use muriate, perchlorate, acetate, vitriol, nitrate or the preparation of their mixture; NaOH can be any oxyhydroxide in the alkali aqueous solution, NaNO ₃Can be other any sodium salt or sylvite.In the preparation of layered hydroxide precursor, the water of use has removed wherein dissolved CO in advance ₂Contain CO if desire to make in the layered hydroxide precursor ₃ ^2-, just needn't remove wherein dissolved CO ₂

Beneficial effect: what the present invention relates to is a kind of fluorescent material that ultraviolet ray is changed into coloured visible light and preparation method thereof.This fluorescent material is matrix with the tricalcium aluminate, and rare earth ion is an activator.Under the ultra violet lamp of 260nm, send visible (coloured) fluorescence.This material is inexpensive, loose, transparent to ruddiness and infrared light, be easy to pulverize, and can be used as luminescent lamp, PDP fluorescent material or other converts UV-light in the field of visible light.

Description of drawings

Fig. 1: layered hydroxide precursor [Ca _3-xAl ₂Eu _x(OH) ₁₀] (NO ₃) _2+xXRD figure spectrum, wherein (a) is [Ca _3-xAl ₂Eu _x(OH) ₁₀] (NO ₃) _2+x(b) be [Ca ₂Al (OH) ₆] (NO ₃).

Fig. 2: Ca ₃Al ₂O ₆: the XRD figure spectrum of Eu,

Fig. 3: Ca ₃Al ₂O ₆: the SEM figure of Eu,

Fig. 4: Ca ₃Al ₂O ₆: the excitation spectrum of Eu,

Fig. 5; Ca ₃Al ₂O ₆: the emmission spectrum of Eu.

Embodiment

The present invention adopts coprecipitation method to prepare the layered hydroxide precursor, and roasting at a certain temperature is three hours then, grinds a little and promptly gets the fluorescent material that needs.This texture material is soft, is easy to pulverize, and can be used for ultraviolet ray is converted to the occasion of coloured visible light.

The material of the present invention's report has following desirable composition the: Ca ₃Al ₂O ₆: RE (RE is an activator ion).This fluorescent material is with tricalcium aluminate Ca ₃Al ₂O ₆Be matrix, rare earth ion RE is an activator.

1.Ca ₃Al ₂O ₆: the RE Preparation of Fluorescent Material

(1) Ca ₃Al ₂O ₆: Eu ³⁺The preparation of red fluorescence material

At first the distilled water that obtain solution is used boils or feeds rare gas element, as nitrogen, argon gas etc., to remove wherein carbon dioxide dissolved.

Secondly, preparation contains Ca ²⁺, Al ³⁺, Eu ³⁺The aqueous solution, wherein three kinds of cationic molar fractions are respectively Ca ²⁺: 0.4～0.7; Al ³⁺: 0.6～0.3; Eu ³⁺: 0.005～0.05.Method is to take by weighing Ca (NO ₃) ₂4H ₂O and Al (NO ₃) ₃9H ₂O, preparation calcium aluminium mixing salt solution.The Eu of calculated amount ₂O ₃Be dissolved in the nitric acid, be made into Eu ³⁺Solution.Then above-mentioned two kinds of solution are mixed, obtain mixing salt solution; Other gets an amount of alkali, as at least a and NaNO of sodium hydroxide, potassium hydroxide ₃Be mixed with the aqueous solution.Alkali and NaNO ₃Consumption be respectively 1.5～2.3 times of above three kinds of total consumptions of metallic cation.

500 rev/mins～1500 rev/mins of stir speed (S.S.)s, rare gas element (as nitrogen, argon gas) protection slowly adds in the mixed-salt aqueous solution down with alkaline solution, and the pH of control alkali consumption solution when precipitin reaction is finished is between 7～10.Alkaline solution add finish after, under the temperature between the room temperature to 120 ℃, continue in reactor, to stir 1～24 hour.Filter then, washing, 40～100 ℃ in vacuum dry 1～3 day is down ground, and makes to contain Ca ²⁺, Al ³⁺, Eu ³⁺The layered hydroxide presoma.

It is some to get the layered hydroxide precursor samples that makes, and in High Temperature Furnaces Heating Apparatus, 1000～1450 ℃ of following roastings 3 hours, furnace cooling promptly obtained the red fluorescence material that needs then.

(2) other color Preparation of Fluorescent Material

With the Eu in the top mixing salt solution ³⁺Salt changes other rare earth metal into (as Ce ³⁺, Pr ³⁺, Sm ³⁺, Tb ³⁺, Dy ³⁺, Yb ³⁺Or the like) salt, other steps are the same, can obtain containing the embedded photoluminescent material of different activator.It should be noted that and in layered hydroxide precursor roasting process, may use oxidisability, inertia or reducing atmosphere as required.

2. the sign of material

Fig. 1 has provided and has consisted of [Ca _3-xAl ₂Eu _x(OH) ₁₀] (NO ₃) _2+xXRD figure spectrum.It has whole features of layered hydroxide XRD figure spectrum, and with [the Ca that makes by literature method ₂Al (OH) ₆] NO ₃H ₂The O collection of illustrative plates is basic identical.This explanation product is single phase.Fig. 2 has provided the fluorescent material Ca that makes ₃Al ₂O ₆: Eu ³⁺XRD figure spectrum, it and Ca ₃Al ₂O ₆Basic identical.

Fig. 3 is Ca ₃Al ₂O ₆: Eu ³⁺The SEM image of fluorescent material, as can be seen from the figure, this material is unformed solid, is formed by the particle agglomeration of several nanometer sizes.Find when it is ground that this material hardness is less, easily pulverize.

3.Ca ₃Al ₂O ₆: Eu ³⁺The photoluminescent property of red fluorescence material

Fig. 4 is Ca ₃Al ₂O ₆: Eu ³⁺Excitation spectrum.As can be seen, this material has a very wide excitation band between 200～300nm, and the position at maximum excitation peak is near the 250nm.Fig. 5 is its emmission spectrum under the ultraviolet excitation of 260nm, and the position of its maximum emission peak shows as the fluorescence of orange near 614nm.Emmission spectrum is Eu ³⁺Characteristic spectrum.

Claims (6)

1. the fluorescent material that UV-light can be changed into coloured visible light is characterized in that this fluorescent material is with tricalcium aluminate Ca ₃Al ₂O ₆Be matrix, rare earth ion RE is an activator, and chemical formulation is Ca ₃Al ₂O ₆: RE; In it was formed, Ca, Al atom number ratio were a little less than 3:2, and described rare earth ion activator RE is Ce ³⁺, Pr ³⁺, Sm ³⁺, Eu ³⁺, Eu ²⁺, Tb ³⁺, Dy ³⁺, Yb ³⁺A kind of in the ion.

2. Preparation of Fluorescent Material method that UV-light can be changed into coloured visible light as claimed in claim 1 is characterized in that the preparation method is as follows:

1) at first use coprecipitation method to prepare a kind of layered hydroxide precursor [Ca that contains the indefinite crystal water of quantity _3-xAl ₂RE _x(OH) ₁₀] X _2+xThe x span is 0.001～0.3; RE is Ce ³⁺, Pr ³⁺, Sm ³⁺, Eu ³⁺, Tb ³⁺, Dy ³⁺, Yb ³⁺A kind of in the ion; X is NO ₃ ^-, Cl ^-, SO4 ^2-, CO ₃ ^2-, ClO ₄ ^-, one or more of acetate;

2.) under 1000～1500 ℃ of temperature in inertia, oxidisability or reducing atmosphere the above-mentioned precursor of roasting can obtain fluorescent material Ca ₃Al ₂O ₆: RE.

3. the Preparation of Fluorescent Material method that UV-light can be changed into coloured visible light according to claim 2 is characterized in that the preparation method of layered hydroxide precursor is:

1) preparation hybrid metal salt brine solution: press Ca ²⁺, Al ³⁺, RE ³⁺Molar fraction be respectively Ca ²⁺: 0.4～0.7; Al ³⁺: 0.6～0.3; RE ³⁺: 0.005～0.05 ratio takes by weighing raw material; If RE ³⁺Raw material is an oxide compound, then earlier it is dissolved in the nitric acid, is made into RE ³⁺Nitrate solution, will contain Ca then ²⁺, Al ³⁺Raw material add above-mentioned solution, promptly get the hybrid metal salt brine solution;

2) preparation alkali aqueous solution: being equivalent to Ca respectively ²⁺, Al ³⁺, RE ³⁺NaOH that total mole number is 1.5～2.3 times and NaNO ₃Soluble in water, promptly get alkali aqueous solution;

3) slowly add at the following alkaline solution of violent stirring and be equipped with in the reactor of hybrid metal salt brine solution, control reaction temperature is that the pH value of final blending reaction solution is 7～10 between the room temperature to 120 ℃; The suspension that obtains continued stirring reaction 24 hours, filtered then, washing, vacuum-drying get final product.

4. the Preparation of Fluorescent Material method that UV-light can be changed into coloured visible light according to claim 3, it is characterized in that among the preparation method of layered hydroxide precursor that the hybrid metal salt brine solution uses muriate, perchlorate, acetate, vitriol, nitrate or the preparation of their mixture.

5. the Preparation of Fluorescent Material method that UV-light can be changed into coloured visible light according to claim 3 is characterized in that in the preparation of layered hydroxide precursor that the water of use has removed wherein dissolved CO in advance ₂Contain CO if desire to make in the layered hydroxide precursor ₃ ^2-, just needn't remove wherein dissolved CO ₂

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