CN115677349B - A fluorescent ceramic material with broad-spectrum red light emission and its preparation method - Google Patents

Abstract

The invention discloses a fluorescent ceramic material with wide-spectrum red light emission, which is characterized in that its general chemical formula is Y ₃ (Mn _x Al _1‑x‑y Sc _y ) ₅ O ₁₂ , where 0.0002≤x≤ 0.005, 0<y≤0.3. Weigh Al ₂ O ₃ , Y ₂ O ₃ , Sc ₂ O ₃ and MnCO ₃ raw material powders according to the stoichiometric ratio, add sintering aids and solvents; ball mill, dry, and sieve to obtain mixed powders; then dry press and cold isostatic pressing to obtain a green body; after high-temperature vacuum sintering and double-sided polishing, a Y ₃ (Mn _x Al _1‑x‑y Sc _y ) ₅ O ₁₂ fluorescent ceramic material is obtained.

Description

A fluorescent ceramic material with broad-spectrum red light emission and its preparation method

technical field

The invention belongs to the field of inorganic luminescent materials, and relates to a fluorescent ceramic material, in particular to a fluorescent ceramic material with wide-spectrum red light emission and a preparation method thereof.

Background technique

As the fourth-generation lighting source, white LED has a wide range of applications in solid-state lighting, projection display and other fields due to its significant advantages such as low energy consumption, high efficiency, long life, and no pollution. At present, the most extensive and mature technical solution for white LEDs is phosphor converted white LED, also commonly known as PC-LED, that is, the phosphor is packaged with blue light chips through resin, silica gel and other organic substances, and through blue light and Fluorescence mixes to create a white light effect. However, the disadvantages of organic packaging materials such as poor heat resistance and easy aging are difficult to meet the application of white light LEDs in high-power applications. Fluorescent ceramic materials can effectively replace the traditional Ce:YAG phosphor + resin technical solution due to their significant advantages such as high thermal conductivity, low light attenuation, and strong thermal shock resistance.

However, Ce:YAG fluorescent ceramics still face the lack of red light components in the spectrum, resulting in low color rendering index and poor light and color quality. At present, the CaAlSiN ₃ :Eu ²⁺ red fluorescent material doped with rare earth ions Eu ²⁺ is limited by the complex preparation process and low preparation efficiency, while the K ₂ SiF ₆ :Mn ⁴⁺ phosphor faces poor deliquescence resistance and relatively low emission spectrum. narrow puzzle. Therefore, there is an urgent need to find an oxide red phosphor with simple preparation process and low cost. In many schemes, the Al ³⁺ in the center of the octahedron in the YAG garnet structure is replaced by Mn ²⁺ ions, resulting in ^{a 6} A ₁ → ⁴ T ₁ transition and an orange emission peak with a center wavelength near 600nm, although Mn ² The emission peak of ⁺ alleviates the problem of missing red light to a certain extent, but compared with sunlight, the emission in the red region (>650nm) is still lacking. The researchers realized the tunable luminescence of Mn ²⁺ /Mn ⁴⁺ by adjusting the ratio of Al/Ga in the Gd ₃ (Al,Ga) ₅ O ₁₂ phosphor matrix. However, the introduction of Ga ³⁺ will significantly reduce the luminescence of the garnet system. The large band gap leads to the sinking of the conduction band, which is easy to generate thermal ionization, which makes the thermal stability of the fluorescent material decrease significantly. In addition, due to the large Stokes shift loss, at the operating temperature of the LED chip (150°C), the emission intensity of the red fluorescent material usually decreases by more than 20% compared with room temperature, which further limits Application of red-emitting fluorescent ceramic materials in high-quality solid-state lighting.

Contents of the invention

One of the objects of the present invention is to provide a fluorescent ceramic material with broad spectrum red light emission, wide emission spectrum and good thermal stability.

The second object of the present invention is to provide a method for preparing the above-mentioned fluorescent ceramic material with broad-spectrum red light emission, which can realize mass production.

To achieve the above object, the technical scheme adopted in the present invention is as follows:

A fluorescent ceramic material with broad-spectrum red light emission, its general chemical formula is Y ₃ (Mn _x Al _1-xy Sc _y ) ₅ O ₁₂ , wherein, 0.0002≤x≤0.005, 0<y≤0.3, 0< y≤0.3.

The fluorescent ceramic material with broad-spectrum red light emission of the present invention simultaneously emits orange fluorescence of Mn ²⁺ with a dominant wavelength of 580-630nm and Mn ⁴⁺ with a dominant wavelength of 670-710nm under the excitation of blue light of 440-460nm of red fluorescence. When the ambient temperature is 150-200°C, the luminous intensity of the fluorescent ceramics decays by 5%-10%. Under the excitation of blue LED with a wavelength of 450-460nm, the variation range of the color coordinates (x, y) is: 0.64<x<0.67, 0.33<y<0.35.

The present invention also provides a method for preparing the above-mentioned fluorescent ceramic material with broad-spectrum red light emission, comprising the following steps:

Step 1, according to the chemical formula Y ₃ (Mn _x Al _1-xy Sc _y ) ₅ O ₁₂ , weigh Al ₂ O ₃ , Y ₂ O ₃ , MnCO ₃ and Sc ₂ O ₃ raw material powders, add tetraethyl orthosilicate (TEOS) 0.1～0.5wt.% is used as sintering aid, and absolute ethanol is added as solvent, the mass ratio of raw material powder to absolute ethanol is 1:1～1:2;

Step 2, put the raw material powder material weighed in step 1 into a ball mill tank, and add balls at the same time to carry out planetary ball milling, the ball milling speed is 120-180r/min, and the ball milling time is 12-24h;

Step 3, drying the ball-milled slurry in step 2 at a temperature of 40-60° C. for 10-24 hours, then pulverizing the dried slurry, and passing through a 100-200 mesh sieve to obtain a mixed powder;

In step 4, the mixed powder in step 3 is subjected to equiaxed bidirectional pressure molding at a pressure of 2-5 MPa, followed by cold isostatic pressing at a pressure of 200-300 MPa and a holding time of 200-400 s to obtain a ceramic element Blank;

Step 5, vacuum sintering the ceramic green body without annealing, and then performing double-sided polishing treatment to obtain Y ₃ (Mn _x Al _1-xy Sc _y ) ₅ O ₁₂ fluorescent ceramic material.

As an improvement, the sintering temperature described in step 5 is 1600-1750° C., and the temperature is kept for 5-24 hours.

Beneficial effect:

Compared with the prior art, the present invention has the following beneficial effects:

与

与

的“尺寸匹配”效应，使得发射光谱同时包括Mn²⁺的橙红色以及Mn⁴⁺的红色荧光。1. The fluorescent ceramic material with broad-spectrum red light emission provided by the present invention adopts Mn ions and Sc ions to partially replace the Al ion sites in the center of the octahedron at the same time.

and

and

The "size-matching" effect makes the emission spectrum include the orange-red fluorescence of Mn ²⁺ and the red fluorescence of Mn ⁴⁺ at the same time.

2. After introducing Sc ³⁺ into the YAG matrix of the fluorescent ceramic material with broad-spectrum red light emission provided by the present invention, the lattice rigidity of the material is enhanced, the thermal stability is improved, and the luminous intensity attenuates at 150-200°C 5-10%.

The fluorescent ceramic material with wide-spectrum red light emission provided by the present invention can simultaneously emit orange fluorescence of Mn ²⁺ with a dominant wavelength of 580-650nm under the excitation of a blue LED chip with a luminous wavelength of 440-460nm, and a dominant wavelength of 580-650nm. Red fluorescence of Mn ⁴⁺ at 670-710 nm.

Description of drawings

Fig. 1 is the x-ray diffraction spectrum of the fluorescent ceramic material with broad-spectrum red light emission prepared in Example 1 of the present invention, the abscissa is the incident angle of x-rays, and the ordinate is the diffraction intensity;

Fig. 2 is the X-ray photoelectron energy spectrum diagram of the fluorescent ceramic material Mn ion with broad-spectrum red light emission prepared in Example 1-2 of the present invention;

Fig. 3 is the fluorescent spectrum of the fluorescent ceramic material with broad-spectrum red light emission prepared in Example 1 of the present invention;

Fig. 4 is the fluorescence lifetime curve at 625nm of the fluorescent ceramic material with broad-spectrum red light emission prepared in Example 1 of the present invention;

Fig. 5 is the fluorescence lifetime curve at 698 nm of the fluorescent ceramic material with broad-spectrum red light emission prepared in Example 1 of the present invention.

Detailed ways

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

To prepare 60g of the target product, weigh the raw material powder ingredients respectively in Table 1. The measurement methods involved in the following examples are all conventional technical means in the art, and the materials are all commercialized finished products, which will not be repeated here.

The list of ingredients of table 1 embodiment

serial number <![CDATA[1^#]]> <![CDATA[2^#]]> <![CDATA[3^#]]> <![CDATA[4^#]]> x 0.0002 0.001 0.0005 0.005 the y 0.1 0.2 0.15 0.3 <![CDATA[MnCO₃]]> 0.011g 0.056g 0.028g 0.277g <![CDATA[Al₂O₃]]> 22.835g 19.970g 21.395g 17.084g <![CDATA[Y₂O₃]]> 33.721g 33.212g 33.367g 32.644g <![CDATA[Sc₂O₃]]> 3.432g 6.761g 5.110g 9.975g TEOS 0.06g 0.12g 0.08g 0.3g alcohol solvent 30g 50g 45g 60g

Example 1

A fluorescent ceramic material with broad spectrum red light emission, its general chemical formula is Y ₃ (Mn _0.0002 Al _0.8998 Sc _0.1 ) ₅ O ₁₂

The preparation method of the above-mentioned fluorescent ceramic material comprises the following steps:

Step 1. Weigh Al ₂ O ₃ , Y ₂ O ₃ , MnCO ₃ and Sc ₂ O ₃ raw material powders according to the mass ratio and stoichiometric ratio shown in 1# in Table 1, and the sintering aid tetraethyl orthosilicate (TEOS ), and alcohol as a solvent;

Step 2, put the raw material powder weighed in step 1 into a ball mill tank, and add balls at the same time to carry out planetary ball milling, the ball milling speed is 130r/min, and the ball milling time is 15h;

Step 3, drying the slurry after ball milling in step 2 at a drying temperature of 40° C. for 20 hours, then pulverizing the dried slurry and passing through a 100-mesh sieve to obtain a mixed powder;

Step 4, subjecting the mixed powder in step 3 to equiaxed bidirectional press molding at a pressure of 2 MPa, followed by cold isostatic pressing at a pressure of 200 MPa and a holding time of 200 s to obtain a ceramic green body;

Step 5: Carry out vacuum sintering of the ceramic green body obtained in step 4, the sintering temperature is 1600°C, keep it warm for 5 hours, then do not need annealing, and finally perform double-sided polishing treatment to obtain Y ₃ (Mn _0.0002 Al _0.8998 Sc _0.1 ) ₅ O ₁₂ Fluorescent ceramic material.

See accompanying drawing 1, the X-ray diffraction pattern of the Y ₃ (Mn _0.0002 Al _0.8998 Sc _0.1 ) ₅ O ₁₂ fluorescent ceramic material prepared in this example, the XRD test results show that the prepared Y ₃ (Mn _0.0002 Al _0.8998 Sc _0.1 ) The X-ray diffraction peaks of ₅ O ₁₂ fluorescent ceramics are consistent with the standard card of YAG (JCPDS (#34-0379)), which is pure garnet phase.

See accompanying drawing 2, the x-ray photoelectron spectrum (XPS) of the Mn ion 2p _3/2 orbital in the Y ₃ (Mn _0.0002 Al _0.8998 Sc _0.1 ) ₅ O ₁₂ fluorescent ceramic material prepared in this embodiment, the XPS package with the peak at 640eV The envelope peak corresponds to the characteristic peak of Mn ²⁺ , and the envelope peak at 642eV corresponds to the characteristic peak of Mn ⁴⁺ . It can be seen from the figure that the characteristic peak intensity of Mn ⁴⁺ is significantly higher than that of Mn ²⁺ , and the integrated intensity ratio of Mn ⁴⁺ to Mn ²⁺ is 11:1.

See Figure 3, the fluorescence spectrum of the Y ₃ (Mn _0.0002 Al _0.8998 Sc _0.1 ) ₅ O ₁₂ fluorescent ceramic material prepared in this example under the excitation of 460nm excitation light. It can be seen from the figure that there are multiple light-emitting regions in the region where the light can be emitted, including the orange fluorescence of Mn ²⁺ with a dominant wavelength of 625nm, and the red fluorescence of Mn ⁴⁺ with a dominant wavelength of 698nm.

See Figure 4, the fluorescence decay curve of the emission peak at 625nm of the Y ₃ (Mn _0.0002 Al _0.8998 Sc _0.1 ) ₅ O ₁₂ fluorescent ceramic material prepared in this example under the excitation of 300nm excitation light. It can be seen from the figure that the curve shows a double-exponential decay trend, and the calculated fluorescence lifetime is 0.076ms, which corresponds to the fluorescence lifetime of Mn ²⁺ .

See Figure 5, the fluorescence decay curve of the emission peak at 698nm of the Y ₃ (Mn _0.0002 Al _0.8998 Sc _0.1 ) ₅ O ₁₂ fluorescent ceramic material prepared in this example under the excitation of 300nm excitation light. It can be seen from the figure that the curve presents a mono-exponential decay trend, and the calculated fluorescence lifetime is 1.61ms, which corresponds to the fluorescence lifetime of Mn ⁴⁺ .

The luminous intensity of the Y ₃ (Mn _0.0002 Al _0.8998 Sc _0.1 ) ₅ O ₁₂ fluorescent ceramics prepared in this example decreases gradually as the temperature increases, and the luminous intensity decreases by 5% at 150°C.

The Y ₃ (Mn _0.0002 Al _0.8998 Sc _0.1 ) ₅ O ₁₂ fluorescent ceramic material prepared in this example is excited by a 450nm blue LED, and the color coordinates of the red light obtained are (0.6405, 0.3313).

Example 2

A fluorescent ceramic material with broad spectrum red light emission, its general chemical formula is Y ₃ (Mn _0.001 Al _0.799 Sc _0.2 ) ₅ O ₁₂

The preparation method of the above-mentioned fluorescent ceramic material with broad-spectrum red light emission comprises the following steps:

Step 1. Weigh Al ₂ O ₃ , Y ₂ O ₃ , MnCO ₃ , and Sc ₂ O ₃ raw material powders according to the mass ratio and stoichiometric ratio shown in 2# in Table 1, and the sintering aid tetraethyl orthosilicate (TEOS ), and alcohol as a solvent;

In step 2, the raw material powder weighed in step 1 is placed in a ball mill tank, and at the same time, balls are added to carry out planetary ball milling, the ball milling speed is 140r/min, and the ball milling time is 20h;

Step 3, drying the ball-milled slurry in step 2 at a drying temperature of 50° C. for 15 hours, then pulverizing the dried slurry and passing through a 150-mesh sieve to obtain a mixed powder;

Step 4, subjecting the mixed powder in step 3 to equiaxed bidirectional press molding at a pressure of 3 MPa, followed by cold isostatic pressing at a pressure of 250 MPa and a holding time of 250 s to obtain a ceramic green body;

Step 5: Carry out vacuum sintering of the ceramic green body obtained in step 4, the sintering temperature is 1700°C, keep it warm for 10 hours, then do not need annealing, and finally perform double-sided polishing treatment to obtain Y ₃ (Mn _0.001 Al _0.799 Sc _0.2 ) ₅ O ₁₂ Fluorescent ceramic material.

See accompanying drawing 2, the x-ray photoelectron spectrum (XPS) of the Mn ion 2p _3/2 orbital in the Y ₃ (Mn _0.0002 Al _0.8998 Sc _0.1 ) ₅ O ₁₂ fluorescent ceramic material prepared in this embodiment, the XPS package with the peak at 640eV The envelope peak corresponds to the characteristic peak of Mn ²⁺ , and the envelope peak at 642eV corresponds to the characteristic peak of Mn ⁴⁺ . It can be seen from the figure that the characteristic peak intensity of Mn ⁴⁺ is higher than that of Mn ²⁺ , and the integrated intensity ratio of Mn ⁴⁺ and Mn ²⁺ is 3:1.

After observation, the main structural properties of the fluorescent ceramic material with broad-spectrum red light emission prepared in Example 2 are similar to those in Example 1.

The luminous intensity of the Y ₃ (Mn _0.001 Al _0.799 Sc _0.2 ) ₅ O ₁₂ fluorescent ceramic material prepared in this example decreases gradually as the temperature increases, and the luminous intensity decreases by 8% at 170°C.

The Y ₃ (Mn _0.001 Al _0.799 Sc _0.2 ) ₅ O ₁₂ fluorescent ceramic material prepared in this example is excited by a 455nm blue LED, and the color coordinates of the red light obtained are (0.6558, 0.3435).

Example 3

A fluorescent ceramic material with broad spectrum red light emission, its general chemical formula is Y ₃ (Mn _0.0005 Al _0.8495 Sc _0.15 ) ₅ O ₁₂

The preparation method of the above-mentioned fluorescent ceramic material with broad-spectrum red light emission comprises the following steps:

Step 1: Weigh Al ₂ O ₃ , Y ₂ O ₃ , MnCO ₃ , and Sc ₂ O ₃ raw material powders according to the mass ratio and stoichiometric ratio shown in 3# in Table 1, and the sintering aid tetraethyl orthosilicate (TEOS ), and alcohol as a solvent;

In step 2, the raw material powder weighed in step 1 is placed in a ball mill tank, and at the same time, balls are added to carry out planetary ball milling, the ball milling speed is 140r/min, and the ball milling time is 20h;

Step 3, drying the ball-milled slurry in step 2 at a drying temperature of 55°C for 16 hours, then pulverizing the dried slurry and passing it through a 150-mesh sieve to obtain a mixed powder;

Step 4, subjecting the mixed powder in step 3 to equiaxed bidirectional press molding at a pressure of 4 MPa, followed by cold isostatic pressing at a pressure of 280 MPa and a holding time of 280 s to obtain a ceramic green body;

Step 5: Carry out vacuum sintering of the ceramic green body obtained in step 4, the sintering temperature is 1720°C, keep it warm for 11 hours, then do not need annealing, and finally carry out double-sided polishing treatment to obtain Y ₃ (Mn _0.0005 Al _0.8495 Sc _0.15 ) ₅ O ₁₂ Fluorescent ceramic material.

After observation, the main structural properties of the fluorescent ceramic material with broad-spectrum red light emission prepared in Example 2 are similar to those in Example 1.

The luminous intensity of the Y ₃ (Mn _0.0005 Al _0.8495 Sc _0.15 ) ₅ O ₁₂ fluorescent ceramic material prepared in this example decreases gradually as the temperature increases, and the luminous intensity decreases by 8.5% at 180°C.

The Y ₃ (Mn _0.0005 Al _0.8495 Sc _0.15 ) ₅ O ₁₂ fluorescent ceramic material prepared in this example is excited by a 455nm blue LED, and the color coordinates of the red light obtained are (0.6433, 0.3345).

Example 4

A fluorescent ceramic material with broad spectrum red light emission, its general chemical formula is Y ₃ (Mn _0.005 Al _0.695 Sc _0.3 ) ₅ O ₁₂

The preparation method of the above-mentioned fluorescent ceramic material with broad-spectrum red light emission comprises the following steps:

Step 1, weighing Al ₂ O ₃ , Y ₂ O ₃ , MnCO ₃ and Sc ₂ O ₃ raw material powders, sintering aids, and alcohol as solvents according to the mass ratio and stoichiometric ratio shown in 4# in Table 1;

Step 2, put the powder raw material weighed in step 1 in the ball mill tank, and add balls at the same time to carry out planetary ball milling, the ball milling speed is 150r/min, and the ball milling time is 18h;

Step 3, drying the ball-milled slurry in step 2 at a drying temperature of 60° C. for 12 hours, then pulverizing the dried slurry and passing it through a 200-mesh sieve to obtain a mixed powder;

Step 4, subjecting the mixed powder in step 3 to equiaxed bidirectional press molding at a pressure of 4 MPa, followed by cold isostatic pressing at a pressure of 300 MPa and a holding time of 300 s to obtain a ceramic green body;

Step 5: Carry out vacuum sintering of the ceramic green body obtained in step 4, the sintering temperature is 1750°C, keep it warm for 24 hours, then do not need annealing, and finally carry out double-sided polishing treatment to obtain Y ₃ (Mn _0.005 Al _0.695 Sc _0.3 ) ₅ O ₁₂ Fluorescent ceramic material.

After observation, the main structural properties and emission spectrum of the fluorescent ceramic material with broad-spectrum red light emission prepared in Example 3 are similar to those in Example 1.

The luminous intensity of the Y ₃ (Mn _0.05 Al _0.695 Sc _0.3 ) ₅ O ₁₂ fluorescent ceramic material prepared in this example decreases gradually as the temperature increases, and the luminous intensity decreases by 10% at 200°C.

The Y ₃ (Mn _0.05 Al _0.695 Sc _0.3 ) ₅ O ₁₂ fluorescent ceramic material prepared in this example is excited by a 460nm blue LED, and the color coordinates of the red light obtained are (0.6695, 0.3498).

The above is only a preferred embodiment of the present invention, and the scope of protection of the present invention is not limited thereto. Any person familiar with the technical field within the technical scope disclosed in the present invention can obviously obtain the simplicity of the technical solution. Changes or equivalent replacements all fall within the protection scope of the present invention.

Claims (7)

1. A fluorescent ceramic material with broad-spectrum red light emission, characterized in that its general chemical formula is Y ₃ (Mn _x Al _{1-x- y} Sc _y ) ₅ O ₁₂ , wherein, 0.0002≤x≤0.005, 0<y≤0.3. 2. The fluorescent ceramic material with broad-spectrum red light emission according to claim 1, characterized in that, in the general chemical formula of the fluorescent ceramic material with broad-spectrum red light emission, x=0.001～0.003, y= 0.1～0.2. 3. The fluorescent ceramic material with broad-spectrum red light emission according to claim 2, characterized in that, in the general chemical formula of the fluorescent ceramic material with broad-spectrum red light emission, x=0.001, y=0.2. 4. The fluorescent ceramic material with broad-spectrum red light emission according to claim 1-3, characterized in that the fluorescent ceramic material simultaneously emits light with a dominant wavelength of 580-630 nm under the excitation of blue light of 440-460 nm. The orange fluorescence of Mn ²⁺ and the red fluorescence of Mn ⁴⁺ with a dominant wavelength of 670-710nm. 5. The fluorescent ceramic material with broad-spectrum red light emission according to any one of claims 1-3, characterized in that, when the ambient temperature is 150-200°C, the luminous intensity of the fluorescent ceramic decays by 5-10% . 6. The preparation method based on the fluorescent ceramic material with broad-spectrum red light emission according to any one of claims 1-5, characterized in that, comprising the following steps: Step 1, weigh Al ₂ O ₃ , Y ₂ O ₃ , MnCO ₃ and Sc ₂ O ₃ raw material powders according to the chemical formula, add 0.1-0.5 wt.% tetraethyl orthosilicate (TEOS) as a sintering aid, and add Absolute ethanol is used as a solvent, and the mass ratio of raw material powder to absolute ethanol is 1:1～1:2; Step 2, put the raw material powder weighed in step 1 into a ball mill tank, and at the same time add balls to carry out planetary ball milling, the ball milling speed is 120-180r/min, and the ball milling time is 12-24h; Step 3, drying the ball-milled slurry in step 2 at a temperature of 40-60° C. for 10-24 hours, then pulverizing the dried slurry and passing through a 100-200 mesh sieve to obtain a mixed powder; In step 4, the mixed powder in step 3 is subjected to equiaxed bidirectional pressure molding at a pressure of 2 to 5 MPa, followed by cold isostatic pressing at a pressure of 200 to 300 MPa and a holding time of 200 to 400 s to obtain a ceramic element Blank; Step 5, vacuum sintering the ceramic green body without annealing, and then performing double-sided polishing treatment to obtain Y ₃ (Mn _x Al _{1-x- y} Sc _y ) ₅ O ₁₂ fluorescent ceramic material. 7 . The method for preparing fluorescent ceramic materials with broad-spectrum red light emission according to claim 6 , characterized in that, in step 5, the sintering temperature is 1600-1750° C. and the temperature is kept for 5-24 hours.

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