CN111057547B - A kind of silicon carbide modified YAG:Ce phosphor and preparation method thereof - Google Patents

Abstract

The invention discloses silicon carbide modified YAG-Ce fluorescent powder and a preparation method thereof. The chemical general formula of the fluorescent powder is Y _{3‑ x} Al ₅ O ₁₂ xCe, ySiC, where 0<x≤0.09，0<y is less than or equal to 0.05; ce fluorescence of YAG modified by silicon carbideThe powder emits yellow fluorescence with the dominant wavelength of 556 +/-2 nm under the excitation of blue light of 460 nm. Compared with the prior art, the invention improves the thermal stability of the YAG-Ce fluorescent powder while ensuring red shift of the emission spectrum and higher luminous efficiency.

Description

A kind of silicon carbide modified YAG:Ce phosphor and preparation method thereof

technical field

The invention belongs to the field of inorganic light-emitting materials, and relates to a silicon carbide modified YAG:Ce phosphor and a preparation method thereof.

Background technique

With the continuous intensification of energy problems, energy conservation and environmental protection have become one of the themes of development in countries around the world. Light Emitting Diode (LED for short) has the characteristics of low energy consumption, high efficiency, no pollution, long life, etc.

The most commonly used white light LED on the market is phosphor-converted white light LED. White light is obtained by coating a phosphor layer on the surface of the LED chip. Therefore, the performance of the phosphor plays a key role in the performance of the white light LED device. Yellow YAG:Ce phosphors are widely used in white LED devices due to their high luminous efficiency, stable physical and chemical properties, and simple preparation process. However, YAG:Ce phosphors also have some shortcomings, such as the lack of red light components in the emission spectrum, which leads to high color temperature and low color rendering index of white LED light sources; in addition, its luminous efficiency and thermal stability still have room for improvement. Therefore, research on the modification of YAG:Ce phosphors has important practical value.

In recent years, many researchers have carried out research on YAG:Ce modification by adding Si compounds (Si ₃ N ₄ , SiO2, etc.). Taking the addition of Si ₃ N ₄ as an example, this method can effectively red-shift the emission spectrum of YAG:Ce phosphors, but at the same time, it is accompanied by the problems of thermal stability and luminous efficiency, which is unfavorable for white LED light sources. , especially for high-power white LED light sources. So what effect does the addition of SiC have on the luminescence properties of YAG:Ce phosphors? There is no research report on this aspect.

SUMMARY OF THE INVENTION

The purpose of the present invention is to carry out modification research on YAG:Ce to improve its thermal stability and maintain high luminous efficiency while red-shifting its emission spectrum. In order to achieve the above purpose, the present invention provides a silicon carbide modified YAG:Ce phosphor and a preparation method thereof.

A silicon carbide modified YAG:Ce phosphor, the general chemical formula of which is Y _3-x Al ₅ O ₁₂ :xCe,ySiC, wherein 0<x≤0.09, 0<y≤0.05; the silicon carbide modified The YAG:Ce phosphor emits yellow fluorescence with a dominant wavelength of 556±2 nm when excited by blue light at 460 nm.

The preparation method of the above-mentioned silicon carbide modified YAG:Ce phosphor, comprises the following steps:

Step 1, according to the chemical formula Y _3-x Al ₅ O ₁₂ :xCe, the stoichiometric ratio of each element in ySiC, respectively weigh Y ₂ O ₃ , Al ₂ O ₃ , CeO ₂ , nano-SiC, where 0<x ≤0.09, 0<y≤0.05, use a planetary ball mill for 10-20 h to obtain the precursor mixture;

Step 2, put the precursor mixture into a high-purity alumina crucible, and then place the high-purity alumina crucible in a high-temperature tubular furnace, in a reducing atmosphere, at 1400-1600 °C, and keep it for 3-8 h, and the heating rate is 300-600 ℃/h, the synthesized phosphor cools naturally with the furnace body;

Step 3, take out the synthesized phosphor, put it into a beaker filled with deionized water, add concentrated hydrochloric acid with a mass fraction of 36%-38%, wherein the volume ratio of deionized water and concentrated hydrochloric acid is 10:1, and at 100 Stir at ℃ for 10-60 min, stand for stratification, filter out the supernatant liquid, wash the precipitate with deionized water and ethanol, put it in a drying oven, and keep it at 70 ℃ for 10-20 h to obtain silicon carbide Modified YAG:Ce phosphor.

As an improvement, the SiC described in step 1 is high-purity nano-SiC with a purity of 99.9% and a particle size of about 40 nm.

As an improvement, the reducing atmosphere in step 2 is H ₂ /N ₂ or H ₂ /Ar.

Beneficial effects:

Compared with the prior art, the advantages of the present invention are as follows:

(1) The effect of SiC on the luminescence properties of YAG:Ce phosphors was studied for the first time;

(2) The modified phosphor has higher thermal stability and maintains higher luminous efficiency while the emission spectrum is red-shifted.

Description of drawings

Fig. 1 is the XRD pattern of the phosphor powder synthesized by Comparative Example 1 and Example 2 in the present invention;

2 is a scanning electron microscope photograph of phosphors synthesized in Comparative Example 1 and Example 2 in the present invention, (a) is Comparative Example 1, and (b) is Example 2;

Fig. 3 is the emission spectrum of the phosphor powder synthesized by Comparative Example 1 and Example 2 in the present invention;

4 is a thermal stability curve of the phosphors synthesized in Comparative Example 1 and Example 3 of the present invention.

Detailed ways

The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

Comparative Example 1: Y _2.925 Al ₅ O ₁₂ : 0.075Ce

(1) Set the mass of the target product Y _2.925 Al ₅ O ₁₂ : 0.075Ce to 20 g, and weigh Y ₂ O ₃ (99.99 %), Al ₂ O ₃ (99.99%), CeO ₂ (99.99%) raw materials, and the precursor mixture was obtained by ball milling with a planetary ball mill for 10-20 h;

(2) Put the precursor mixture obtained in step (1) into a high-purity alumina crucible, and then place it in a high-temperature tubular furnace, in a reducing atmosphere, at 1500 °C for 5 h, and the heating rate is 600 °C/h , the synthesized phosphor cools naturally with the furnace body;

(3) Take out the phosphor powder synthesized in step (2), put it into a beaker filled with deionized water, and add concentrated hydrochloric acid whose mass fraction is 36%-38%, wherein the volume ratio of deionized water and concentrated hydrochloric acid is 10: 1. Stir at 100 °C for 20 min, let stand for stratification, filter out the supernatant liquid, wash with deionized water and ethanol, put it in a drying box, and keep at 70 °C for 10 h to obtain YAG:Ce fluorescence pink.

Example 1: Y _2.925 Al ₅ O ₁₂ : 0.075Ce, 0.01SiC

(1) Set the target product Y _2.925 Al ₅ O ₁₂ : 0.075Ce, the mass of 0.01SiC is 20 g, and the ratio of the amount of Y:Al:Ce:Si is 2.925:5:0.075:0.01, respectively. Take Y ₂ O ₃ (99.99%), Al ₂ O ₃ (99.99%), CeO ₂ (99.99%), SiC (99.9%) raw materials, and use a planetary ball mill for 10-20 h;

(2) Put the precursor mixture obtained in step (1) into a high-purity alumina crucible, and then place it in a high-temperature tubular furnace, in a reducing atmosphere, at 1500 °C for 5 h, and the heating rate is 600 °C/h , the synthesized phosphor cools naturally with the furnace body;

(3) Take out the phosphor powder synthesized in step (2), put it into a beaker filled with deionized water, and add concentrated hydrochloric acid whose mass fraction is 36%-38%, wherein the volume ratio of deionized water and concentrated hydrochloric acid is 10: 1. Stir at 100 °C for 20 min, stand for stratification, filter out the upper clarified liquid, wash with deionized water and ethanol, put it in a drying box, and keep at 70 °C for 10 h to obtain modified silicon carbide. of YAG:Ce phosphors.

Example 2: Y _2.925 Al ₅ O ₁₂ : 0.075Ce, 0.03SiC

(1) Set the target product Y _2.925 Al ₅ O ₁₂ : 0.075Ce, the mass of 0.03SiC is 20 g, and the ratio of the amount of Y:Al:Ce:Si is 2.925:5:0.075:0.03, respectively. Take Y ₂ O ₃ (99.99%), Al ₂ O ₃ (99.99%), CeO ₂ (99.99%), SiC (99.9%) raw materials, and use a planetary ball mill for 10-20 h;

(2) Put the precursor mixture obtained in step (1) into a high-purity alumina crucible, and then place it in a high-temperature tubular furnace, in a reducing atmosphere, at 1500 °C for 5 h, and the heating rate is 600 °C/h , the synthesized phosphor cools naturally with the furnace body;

(3) Take out the phosphor powder synthesized in step (2), put it into a beaker filled with deionized water, and add concentrated hydrochloric acid whose mass fraction is 36%-38%, wherein the volume ratio of deionized water and concentrated hydrochloric acid is 10: 1. Stir at 100 °C for 20 min, stand for stratification, filter out the upper clarified liquid, wash with deionized water and ethanol, put it in a drying box, and keep at 70 °C for 10 h to obtain modified silicon carbide. of YAG:Ce phosphors.

Example 3: Y _2.925 Al ₅ O ₁₂ : 0.075Ce, 0.05SiC

(1) Set the target product Y _2.925 Al ₅ O ₁₂ : 0.075Ce, the mass of 0.05SiC is 20 g, and the ratio of the amount of Y:Al:Ce:Si is 2.925:5:0.075:0.05, respectively. Take Y ₂ O ₃ (99.99%), Al ₂ O ₃ (99.99%), CeO ₂ (99.99%), SiC (99.9%) raw materials, and use a planetary ball mill for 10-20 h;

(2) Put the precursor mixture obtained in step (1) into a high-purity alumina crucible, and then place it in a high-temperature tubular furnace, in a reducing atmosphere, at 1500 °C for 5 h, and the heating rate is 600 °C/h , the synthesized phosphor cools naturally with the furnace body;

(3) Take out the phosphor powder synthesized in step (2), put it into a beaker filled with deionized water, and add concentrated hydrochloric acid whose mass fraction is 36%-38%, wherein the volume ratio of deionized water and concentrated hydrochloric acid is 10: 1. Stir at 100 °C for 20 min, stand for stratification, filter out the upper clarified liquid, wash with deionized water and ethanol, put it in a drying box, and keep at 70 °C for 10 h to obtain modified silicon carbide. of YAG:Ce phosphors.

Example 4: Y _2.985 Al ₅ O ₁₂ : 0.015Ce, 0.03SiC

(1) Set the target product Y _2.985 Al ₅ O ₁₂ : 0.015Ce, the mass of 0.03SiC is 20 g, and the ratio of the amount of Y:Al:Ce:Si is 2.985:5:0.015:0.03, respectively. Take Y ₂ O ₃ (99.99%), Al ₂ O ₃ (99.99%), CeO ₂ (99.99%), SiC (99.9%) raw materials, and use a planetary ball mill for 10-20 h;

(2) Put the precursor mixture obtained in step (1) into a high-purity alumina crucible, and then place it in a high-temperature tubular furnace, in a reducing atmosphere, at 1500 °C for 5 h, and the heating rate is 600 °C/h , the synthesized phosphor cools naturally with the furnace body;

(3) Take out the phosphor powder synthesized in step (2), put it into a beaker filled with deionized water, and add concentrated hydrochloric acid whose mass fraction is 36%-38%, wherein the volume ratio of deionized water and concentrated hydrochloric acid is 10: 1. Stir at 100 °C for 20 min, stand for stratification, filter out the upper clarified liquid, wash with deionized water and ethanol, put it in a drying box, and keep at 70 °C for 10 h to obtain modified silicon carbide. of YAG:Ce phosphors.

Example 5: Y _2.91 Al ₅ O ₁₂ : 0.09Ce, 0.03SiC

(1) Set the target product Y _2.91 Al ₅ O ₁₂ : 0.09Ce, the mass of 0.03SiC is 20 g, and the ratio of the amount of Y:Al:Ce:Si is 2.91:5:0.09:0.03, respectively. Take Y ₂ O ₃ (99.99%), Al ₂ O ₃ (99.99%), CeO ₂ (99.99%), SiC (99.9%) raw materials, and use a planetary ball mill for 10-20 h;

(2) Put the precursor mixture obtained in step (1) into a high-purity alumina crucible, and then place it in a high-temperature tubular furnace, in a reducing atmosphere, at 1500 °C for 5 h, and the heating rate is 600 °C/h , the synthesized phosphor cools naturally with the furnace body;

(3) Take out the phosphor powder synthesized in step (2), put it into a beaker filled with deionized water, and add concentrated hydrochloric acid whose mass fraction is 36%-38%, wherein the volume ratio of deionized water and concentrated hydrochloric acid is 10: 1. Stir at 100 °C for 20 min, stand for stratification, filter out the upper clarified liquid, wash with deionized water and ethanol, put it in a drying box, and keep at 70 °C for 10 h to obtain modified silicon carbide. of YAG:Ce phosphors.

Figure 1 shows the XRD of the samples in Comparative Example 1 and Example 2. It can be seen from the figure that after adding SiC, the structure of the material is still a garnet structure, and a pure-phase YAG:Ce phosphor can still be obtained.

The SEM photographs of the samples in Comparative Example 1 and Example 2 are shown in Figure 2 . It can be seen from the figure that the morphology of the synthesized YAG:Ce phosphor is nearly spherical and has good dispersibility; in addition, after adding SiC, the particle size of the YAG:Ce phosphor decreases significantly.

The emission spectra of the samples in Comparative Example 1 and Example 2 are shown in Figure 3 . It can be seen from the figure that the emission spectrum has an obvious red shift, which increases the red light component in the emission spectrum; and basically maintains the original luminous intensity.

The thermal stability curves of the samples in Comparative Example 1 and Example 3 are shown in Figure 4 . It can be seen from the figure that when the modified phosphor is heated to 150 °C, its fluorescence intensity is 94.5% of the fluorescence intensity at room temperature, which is much higher than that of the unmodified phosphor (150 °C, 88.2%), indicating that after modification. The YAG:Ce phosphors have higher thermal stability.

Claims (4)

1. The YAG Ce phosphor modified by silicon carbide is characterized in that the chemical general formula is Y _3-x Al ₅ O ₁₂ xCe, ySiC, where 0<x≤0.09，0<y is less than or equal to 0.05; the silicon carbide modified YAG-Ce fluorescent powder emits yellow fluorescent light with the dominant wavelength of 556 +/-2 nm under the excitation of 460 nm blue light.

2. The preparation method of the silicon carbide modified YAG Ce phosphor based on claim 1 is characterized by comprising the following steps: step 1, according to a chemical general formula Y _3-x Al ₅ O ₁₂ Respectively weighing Y according to the stoichiometric ratio of each element in xCe and ySiC ₂ O ₃ 、Al ₂ O ₃ 、CeO ₂ Nano SiC of which 0<x≤0.09，0<y is less than or equal to 0.05, and a planetary ball mill is adopted for ball milling for 10-20 h to obtain a precursor mixture; step 2, putting the precursor mixture into a high-purity alumina crucible, then placing the high-purity alumina crucible into a high-temperature tubular furnace, preserving the heat for 3-8 h at 1400-1600 ℃ in a reducing atmosphere at the heating rate of 300-600 ℃/h, and naturally cooling the synthesized fluorescent powder along with the furnace body; step 3, taking out the synthesized fluorescent powder, and putting the fluorescent powder into a beaker filled with deionized waterAdding concentrated hydrochloric acid with the mass fraction of 36-38%, wherein the volume ratio of deionized water to concentrated hydrochloric acid is 10:1, stirring for 10-60 min at 100 ℃, standing for layering, filtering out supernatant, washing and precipitating with deionized water and ethanol, placing into a drying box, and preserving heat at 70 ℃ for 10-20 h to obtain the silicon carbide modified YAG: Ce fluorescent powder.

3. The method for preparing Ce phosphor of YAG modified by SiC according to claim 2, wherein the SiC in step 1 is high purity nano SiC with purity of 99.9% and particle size of 40 nm.

4. The method for preparing Ce doped YAG phosphor modified by SiC as claimed in claim 2, wherein the reducing atmosphere in step 2 is H ₂ /N ₂ Or H ₂ /Ar。

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