CN109762564B

CN109762564B - A kind of europium ion Eu3+ activated titanate red phosphor, preparation method and application thereof

Info

Publication number: CN109762564B
Application number: CN201910196664.2A
Authority: CN
Inventors: 唐惠东; 杨蓉
Original assignee: Changzhou Vocational Institute of Engineering
Current assignee: Changzhou Vocational Institute of Engineering
Priority date: 2019-03-13
Filing date: 2019-03-13
Publication date: 2021-04-20
Anticipated expiration: 2039-03-13
Also published as: CN109762564A

Abstract

The invention relates to europium ion Eu³⁺Activated titanate red fluorescent powder, preparation method and application thereofIt belongs to the technical field of inorganic luminescent materials. Wherein the chemical formula of the titanate red fluorescent powder is LaY_1‑xEu_xTi₆O₁₅X is trivalent europium ion Eu³⁺Substituted Y³⁺The number of moles of the ions, x, is more than or equal to 0.001 and less than or equal to 0.5. The red fluorescent powder is prepared by adopting a chemical solution method, is uniform in particle, good in chemical stability and high in excitation efficiency, can be matched with near ultraviolet and blue light LED chips, and is a potential red fluorescent powder raw material for preparing white light LEDs.

Description

Europium ion Eu3+Activated titanate RedColor fluorescent powder, preparation method and application thereof

Technical Field

The invention belongs to the technical field of inorganic fluorescent materials and display, and particularly relates to a europium ion Eu³⁺Activated titanate red fluorescent powder, a preparation method and application thereof.

Background

In recent years, a fluorescence conversion type white light LED device has been widely used in the fields of illumination and display. For an ideal LED lighting device, the LED lighting device is required to have high brightness, and also has optical qualities of low color temperature, high color rendering index, low glare and the like; most of the existing LED lighting equipment is prepared on the basis of matching a blue LED chip with yellow fluorescent powder, and has the obvious defects of insufficient color temperature and obvious cold tone display.

The use of red phosphor can significantly improve the color rendering index of the lighting device and also reduce the color temperature, so that research and development thereof are receiving more and more attention. Wherein Eu³⁺Ion activated red phosphor, is one of the most important candidates. Eu excited by blue light (about 465 nm) or near ultraviolet light (about 395 nm)³⁺The ions can emit red light, and the light emission mainly comprises light from⁵D₀→⁷F₁(595 nm) and⁵D₀→⁷F₂(610-630 nm) electron transition, and hence Eu³⁺The ions are very important activators for red phosphors.

Eu³⁺The ion having 4f⁶Electronic configuration, and the electronic energy level structure is relatively simple, and is one of the ideal ions for fluorescent probes. For one phosphor, by Eu³⁺The fluorescence spectrum structure of the ions can detect the Eu being³⁺The symmetry of the surrounding structure of the ion substituted ion. Therefore, Eu has been recently used³⁺Ion red emission is widely used in color televisions, flat panel displays, cathode ray tubes, and tri-phosphor phosphors. In addition, Eu³⁺Characteristic emission of (A) is derived from⁵D_0,1,2,3-⁷F_J(J-4.., 0) having an energy level structure that is very strong to crystal field and covalent propertySensitive, also applied in the detection of fine structures, and based on Eu³⁺The structural probe characteristics of the ions can also obtain different luminescence characteristics through the regulation and control of the structure, so that the regulation and control of red luminescence can be realized, and the possibility of containing Eu by searching for a proper composite oxide can be realized³⁺A fluorescent powder with pure red luminescence is designed.

Disclosure of Invention

The invention aims to provide a europium ion Eu³⁺The activated titanate red fluorescent powder and the preparation method thereof have the advantages that the prepared red fluorescent powder has uniform particles, good chemical stability and high excitation efficiency, can be matched with near ultraviolet and blue light LED chips, is a potential red fluorescent powder raw material for preparing white light LEDs, adds a new variety to the field, and promotes the wide application of inorganic luminescent materials.

In order to achieve the above object, the present invention discloses a europium ion Eu³⁺Activated titanate red phosphor having a host lattice of LaYTi₆O₁₅The host crystal lattice is characterized in that La and Y ions occupy the same cation crystallographic position in the crystal lattice, and Eu is added³⁺The doping of the ions can cause the lattice position to be fully disturbed, so that Eu³⁺The forbidden transition of ions is thoroughly broken, so that Eu is realized³⁺Ion(s)⁵D₀→⁷F₂Effective electron transition, and thus red light emitting phosphor with high light emitting efficiency is obtained. Moreover, the lattice is composed of Ti-O octahedrons in three-dimensional space, and the resulting lattice has high strength, and therefore, Eu³⁺The luminescence realized by ion doping has good thermal stability, and is a potential red luminescent phosphor.

In particular to europium ion Eu provided by the invention³⁺Activated titanate red phosphor, the chemical expression is: LaY_1-xEu_xTi₆O₁₅X is trivalent europium ion Eu³⁺Substituted Y³⁺The number of moles of the ions, x, is more than or equal to 0.001 and less than or equal to 0.5. Preferably, x is 0.3.

The invention also provides a preparation method of the aboveEuropium ion Eu³⁺The method for activating the titanate red fluorescent powder adopts a chemical solution method and comprises the following specific steps:

(1) according to chemical formula LaY_1-xEu_xTi₆O₁₅The stoichiometric ratio of each element in the raw materials is more than or equal to 0.001 and less than or equal to 0.5, and the raw materials are respectively weighed: containing lanthanum ion La³⁺Compound of (2), containing yttrium ion Y³⁺Compound (b) containing europium ion Eu³⁺The three raw materials are respectively dissolved in deionized water or nitric acid to obtain three transparent solutions. Mixing tetrabutyl titanate and glacial acetic acid according to the mass ratio of 1:1-3, stirring, then dropwise adding into ethanol, adjusting the pH value to be 1-4, and stirring until a fourth transparent solution is formed, wherein the amount of the glacial acetic acid is 1-3 times of the mass of the tetrabutyl titanate.

(2) In the presence of lanthanum ion La³⁺Yttrium ion Y³⁺Europium ion Eu³⁺The three transparent solutions of (2) are added with a certain proportion of complex, and the addition amount is 1-3 times of the molar weight of each cation.

(3) Slowly mixing the four transparent solutions obtained in the steps (1) and (2), stirring for 1-4 hours at the temperature of 40-80 ℃, standing and drying to obtain a precursor;

(4) carrying out primary calcination on the precursor in the step (3) in an air atmosphere, wherein the calcination temperature is 300-650 ℃, and the calcination time is 2-8 hours; naturally cooling, calcining for the second time in an air atmosphere at the calcining temperature of 700-1100 ℃ for 2-10 hours, and grinding to obtain Eu³⁺Activated titanate red phosphor.

The compound containing lanthanum ions in the step (1) is lanthanum oxide La₂O₃La (NO) lanthanum nitrate₃)₃·6H₂One of O; the yttrium ion-containing compound is yttrium oxide Y₂O₃Yttrium nitrate Y (NO)₃)₃·6H₂One of O; the compound containing europium ions is europium oxide Eu₂O₃Eu (NO) nitrate₃)₃·6H₂One of O; the compound containing titanium element is tetrabutyl titanate.

The complex in the step (2) is one of oxalic acid and citric acid.

Preferably, the first calcining temperature in the step (4) is 400-600 ℃, and the calcining time is 3-6 hours;

more preferably, the second calcination temperature in the step (4) is 750-950 ℃ and the calcination time is 3-8 hours.

The titanate red fluorescent powder is used as a fluorescent powder material for preparing an illuminating or displaying device taking near ultraviolet light as an excitation light source, and the fluorescent powder material can be used in a light-emitting diode, a three-primary-color fluorescent lamp and a field emission display.

The invention has the following beneficial effects:

(1) compared with the existing common commercial red-emitting fluorescent powder, such as Y₂O₃:Eu³⁺，Y₂O₂S:Eu³⁺The fluorescent powder disclosed by the patent has stronger light absorption and excitation efficiency in a near ultraviolet wavelength region, so that the fluorescent powder disclosed by the patent is more suitable for preparing white light LED lighting equipment prepared by matching a near ultraviolet LED chip.

(2) La exists in the matrix lattice of the phosphor invented in the patent³⁺And Y³⁺Ions occupy the same cation crystallographic position, plus Eu³⁺The doping of ions leads the lattice position to have sufficient disturbance, thus realizing Eu³⁺Forbidden transitions of ions are broken down completely and red luminescence is efficient.

(3) The matrix lattice of the fluorescent powder has strong rigidity, and Eu is³⁺The red luminescence of (A) has good thermal stability.

Drawings

FIG. 1 is LaY prepared according to example 1 of the present invention_0.7Eu_0.3Ti₆O₁₅X-ray powder diffraction pattern of (a);

FIG. 2 is LaY prepared according to example 1 of the present invention_0.7Eu_0.3Ti₆O₁₅SEM picture of (1);

FIG. 3 is LaY prepared according to example 1 of the present invention_0.7Eu_0.3Ti₆O₁₅Excitation spectrum obtained under 615 nm light monitoring;

FIG. 4 is LaY prepared according to example 1 of the present invention_0.7Eu_0.3Ti₆O₁₅A luminescence spectrum under 395 nm light excitation;

FIG. 5 is LaY prepared according to example 1 of the present invention_0.7Eu_0.3Ti₆O₁₅Graph of luminescence decay.

Detailed Description

The invention is further illustrated by the following examples, which are intended to better understand the content of the invention and not to limit the scope of protection of the invention.

Example 1

Preparation LaY_0.7Eu_0.3Ti₆O₁₅

According to formula LaY_0.7Eu_0.3Ti₆O₁₅The stoichiometric ratio of each element in the La-La mixture is respectively weighed₂O₃: 1.63 g, Y (NO)₃)₃·6H₂O: 2.68 g, Eu (NO)₃)₃·6H₂O: 1.34 g, tetrabutyl titanate: 20.42 grams. Will weigh La₂O₃Dissolving in proper amount of nitric acid solution, diluting with 5 times of deionized water, and stirring. Eu (NO)₃)₃·6H₂O and Y (NO)₃)₃·6H₂O is dissolved in deionized water respectively. Secondly, after complete dissolution, citric acid with 2 times of the molar mass of the cations is added into the solution respectively, and stirring is carried out until a transparent solution is formed. And mixing and stirring the weighed tetrabutyl titanate and glacial acetic acid with the mass of 2 times for a certain time, then dropwise adding the mixture into ethanol, adjusting the pH value to be 2, and stirring until transparent sol is formed. Slowly mixing the four mixed solutions together, stirring for 1 hour at the temperature of 80 ℃, standing and drying to obtain a fluffy precursor; calcining the precursor in air atmosphere at 650 ℃ for 2 hours; naturally cooling and grinding, calcining again in air atmosphere at 950 ℃ for 3 hours to obtain europium ion Eu³⁺Activated titanic acidSalt red fluorescent powder.

See FIG. 1 for sample LaY prepared according to the protocol of example 1_0.7Eu_0.3Ti₆O₁₅The X-ray powder diffraction pattern and XRD (X-ray diffraction) test results show that the prepared material is a single-phase material and has no impurity phase.

Referring to FIG. 2, it is an SEM image of a sample of material prepared according to the technical scheme of example 1, and the material has good crystallization property and uniform particle size.

Referring to fig. 3, which is an excitation spectrum obtained by monitoring emitted light of 615 nm for a sample prepared according to the technical scheme of example 1, it can be seen that an excitation source of red light is mainly in an ultraviolet to blue light region between 200 nm and 500 nm, and can be well matched with emission of an ultraviolet to blue light LED chip.

Referring to fig. 4, it is the emission spectrum obtained by near ultraviolet 395 nm excitation in the phosphor prepared according to the technical scheme of example 1, and the main central emission wavelength is red emission of 615 nm.

Referring to fig. 5, it is a luminescence decay curve of the phosphor prepared according to the technical scheme of example 1 under the monitoring of 615 nm, the luminescence lifetime is 0.84 ms, and the requirements of luminescence illumination and display can be completely satisfied.

Example 2

Preparation LaY_0.5Eu_0.5Ti₆O₁₅

According to formula LaY_0.5Eu_0.5Ti₆O₁₅The stoichiometric ratio of each element in the La-La mixture is respectively weighed₂O₃: 1.63 g, Y₂O₃: 0.56 g, Eu (NO)₃)₃·6H₂O: 2.25 g, tetrabutyl titanate: 20.4192 g. The weighed La is added₂O₃，Y₂O₃Respectively dissolving in proper amount of nitric acid solution, diluting with 5 times of deionized water, and stirring. Eu (NO)₃)₃·6H₂O was dissolved in deionized water. Secondly, after the solution is completely dissolved, oxalic acid with the molar mass of 3 times of that of the cation is added into the solution respectively, and the solution is stirred until a transparent solution is formed. Will be provided withAnd mixing and stirring the weighed tetrabutyl titanate and glacial acetic acid with the mass of 1 time for a certain time, then dropwise adding the mixture into ethanol, adjusting the pH value to be 2, and stirring until transparent sol is formed. Slowly mixing the four mixed solutions together, stirring for 3 hours at the temperature of 50 ℃, standing and drying to obtain a fluffy precursor; calcining the precursor in air atmosphere at the temperature of 450 ℃ for 5 hours; naturally cooling and grinding, calcining again in air atmosphere at 800 ℃ for 6 hours to obtain europium ion Eu³⁺Activated titanate red phosphor. The main structural properties, excitation spectrum, luminescence spectrum and luminescence lifetime are similar to those of example 1.

Example 3

Preparation LaY_0.995Eu_0.005Ti₆O₁₅

According to formula LaY_0.995Eu_0.005Ti₆O₁₅The stoichiometric ratio of each element in the La (NO) is weighed respectively₃)₃·6H₂O: 4.33 g, Y (NO)₃)₃·6H₂O: 3.81 g, Eu₂O₃: 0.009 g, tetrabutyl titanate: 20.4192 g. Weighing Eu₂O₃Dissolving in proper amount of nitric acid solution, diluting with 5 times of deionized water, and stirring. Adding La (NO)₃)₃·6H₂O，Y(NO₃)₃·6H₂O was dissolved in deionized water. Secondly, after complete dissolution, citric acid with the cation molar mass being 1 time is added into the solution respectively, and stirring is carried out until a transparent solution is formed. And mixing and stirring the weighed tetrabutyl titanate and glacial acetic acid with the mass of 3 times for a certain time, then dropwise adding the mixture into ethanol, adjusting the pH value to be 2, and stirring until transparent sol is formed. Slowly mixing the four mixed solutions together, stirring for 2 hours at the temperature of 60 ℃, standing and drying to obtain a fluffy precursor; calcining the precursor in air atmosphere at the temperature of 300 ℃ for 8 hours; naturally cooling and grinding, calcining again in air atmosphere at 700 ℃ for 10 hours to obtain europium ion Eu³⁺Activated titanate red phosphor. The main structural properties, excitation spectrum, luminescence spectrum and luminescence lifetime are similar to those of example 1.

Example 4

Preparation LaY_0.9Eu_0.1Ti₆O₁₅

According to formula LaY_0.9Eu_0.1Ti₆O₁₅The stoichiometric ratio of each element in the La (NO) is weighed respectively₃)₃·6H₂O: 4.33 g, Y (NO)₃)₃·6H₂O: 3.45 g, Eu (NO)₃)₃·6H₂O: 0.45 g, tetrabutyl titanate: 20.42 grams. Weighing La (NO)₃)₃·6H₂O，Y(NO₃)₃·6H₂O，Eu(NO₃)₃·6H₂Dissolving O in deionized water for dilution, and stirring. Secondly, after the solution is completely dissolved, oxalic acid with the molar mass of 3 times of that of the cation is added into the solution respectively, and the solution is stirred until a transparent solution is formed. And mixing and stirring the weighed tetrabutyl titanate and glacial acetic acid with the mass of 2 times for a certain time, then dropwise adding the mixture into ethanol, adjusting the pH value to be 2, and stirring until transparent sol is formed. Slowly mixing the four mixed solutions together, stirring for 1.5 hours at the temperature of 70 ℃, standing and drying to obtain a fluffy precursor; calcining the precursor in air atmosphere at 600 ℃ for 3 hours; naturally cooling and grinding, calcining again in air atmosphere at 1100 deg.C for 2 hr, and grinding to obtain europium ion Eu³⁺Activated titanate red phosphor. The main structural properties, excitation spectrum, luminescence spectrum and luminescence lifetime are similar to those of example 1.

Example 5

Preparation LaY_0.999Eu_0.001Ti₆O₁₅

According to formula LaY_0.999Eu_0.001Ti₆O₁₅The stoichiometric ratio of each element in the La-La mixture is respectively weighed₂O₃: 3.26 g, Y₂O₃: 2.26 g, Eu₂O₃: 0.004 g, tetrabutyl titanate: 40.8384 g. The weighed La is added₂O₃，Y₂O₃And Eu₂O₃Respectively dissolving in proper amount of nitric acid solution, diluting with 5 times of deionized water, and stirring. Secondly, after complete dissolution, citric acid with 2 times of the molar mass of the cations is added into the solution respectively, and stirring is carried out until a transparent solution is formed. And mixing and stirring the weighed tetrabutyl titanate and glacial acetic acid with the mass of 2.5 times for a certain time, then dropwise adding the mixture into ethanol, adjusting the pH value to be 2, and stirring until transparent sol is formed. Slowly mixing the four mixed solutions together, stirring for 4 hours at the temperature of 40 ℃, standing and drying to obtain a fluffy precursor; calcining the precursor in air atmosphere at 400 ℃ for 6 hours; naturally cooling and grinding, calcining again in air atmosphere at 750 ℃ for 8 hours to obtain europium ion Eu³⁺Activated titanate red phosphor. The main structural properties, excitation spectrum, luminescence spectrum and luminescence lifetime are similar to those of example 1.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims

1. a titanate red fluorescent powder activated by europium ion Eu ³⁺ , is characterized in that, the chemical expression of this red fluorescent powder is: LaY _{1- x} Eu _x Ti ₆ O ₁₅ , x is a trivalent europium ion Eu The number of moles of ³⁺ substituted Y ³⁺ ions, and the value range of x is 0.001≤x≤0.5 .

2 . The europium ion Eu ³⁺ activated titanate red phosphor according to claim 1 , wherein the x is 0.3. 3 .

3. a method for preparing the titanate red fluorescent powder activated by europium ion Eu ³⁺ , is characterized in that, concretely adopts chemical solution method, and the steps are as follows:

(1) According to the stoichiometric ratio of each element in the chemical formula LaY _1- _x Eu _x Ti ₆ O ₁₅ of the europium ion Eu ³⁺ -activated titanate red phosphor according to any one of claims 1-2, weigh the Raw materials: compounds containing lanthanum ions La ³⁺ , compounds containing yttrium ions Y ³⁺ , compounds containing europium ions Eu ³⁺ , the three raw materials were dissolved in deionized water or nitric acid respectively to obtain three kinds of transparent solutions; Tetrabutyl acid and glacial acetic acid are mixed in a mass ratio of 1:1-3, then added to ethanol, and the pH value is adjusted between 1-4 to form the fourth transparent solution;

(2) Add complex compounds to three transparent solutions containing lanthanum ions La ³⁺ , yttrium ions Y ³⁺ , and europium ions Eu ³⁺ , and the added amounts are respectively the lanthanum ions La ³⁺ , the yttrium ions Y ³⁺ , 1-3 times the molar amount of Europium ion Eu ³⁺ ;

(3) mixing the fourth transparent solution in step (1) and the solution obtained in (2), stirring at a temperature of 40-80 °C, standing, and drying to obtain a precursor;

(4) The precursor of step (3) is calcined for the first time in an air atmosphere, the calcination temperature is 300-650 ° C, and the calcination time is 2-8 hours; after natural cooling, the second calcination in an air atmosphere, calcination The temperature is 700-1100° C., the calcination time is 2-10 hours, and the Eu ³⁺ activated titanate red phosphor is obtained after grinding.

4 . The method according to claim 3 , wherein the complex in the step (2) is one of oxalic acid and citric acid. 5 .

The method according to claim 3, wherein the compound of lanthanum ion La ³⁺ in the step (1) is lanthanum oxide La ₂ O ₃ , lanthanum nitrate La(NO ₃ ) ₃ ·6H ₂ O One of the yttrium ion Y ³⁺ -containing compound is one of yttrium oxide Y ₂ O ₃ , yttrium nitrate Y(NO ₃ ) ₃ ·6H ₂ O; the europium ion Eu ³⁺ -containing compound is europium oxide Eu One of ₂ O ₃ and Europium nitrate Eu(NO ₃ ) ₃ ·6H ₂ O.

6 . The method according to claim 3 , wherein in the first calcination of the step (4), the calcination temperature is 400-600° C., and the calcination time is 3-6 hours. 7 .

7 . The method according to claim 6 , wherein in the second calcination in the step (4), the calcination temperature is 750-950° C., and the calcination time is 3-8 hours. 8 .

8. An application of the titanate red phosphor prepared according to any one of claims 1-2 or any one of claims 3-7, wherein the titanate red phosphor is Phosphors are used as phosphor materials for preparing illumination or display devices using near-ultraviolet light as the excitation light source.

9 . The application of the titanate red phosphor according to claim 8 , wherein the phosphor material is used in light-emitting diodes, trichromatic fluorescent lamps and field emission displays. 10 .