An abnormal concentration quenching red fluorescent ceramic and a preparation method thereof
By preparing an anomalous concentration quenching red fluorescent ceramic of Mg2-xY1.93Al2Si2O12:0.07Ce3+,xMn2+, the concentration quenching problem caused by Mn2+ doping was solved, achieving high-efficiency red light emission, which is suitable for LED/LD devices.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- XUZHOU NORMAL UNIVERSITY
- Filing Date
- 2024-01-04
- Publication Date
- 2026-06-19
AI Technical Summary
Existing fluorescent ceramics exhibit concentration quenching after Mn2+ doping, resulting in decreased luminescence intensity and a lack of red light components, which limits their application in the lighting field.
Using the molecular formula Mg2-xY1.93Al2Si2O12:0.07Ce3+,xMn2+, anomalous concentration quenching red fluorescent ceramics were prepared by high-temperature solid-state sintering. The molar percentage of Mn2+ doped Mg sites was less than 0.
Under blue light excitation, the fluorescent ceramic emits bright broadband red light. The emission intensity is 1.79 times that of the Mn2+ doping concentration of 0.01 when the doping concentration is 0.05, which shows high efficiency in light emission performance and is suitable for LED/LD devices.
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Figure CN117819969B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of fluorescent ceramics technology, specifically to an anomalous concentration quenching red fluorescent ceramic and its preparation method. Background Technology
[0002] As a fourth-generation lighting source, solid-state lighting (SSL) has been widely used in optoelectronic technologies such as automotive headlights, projection displays, and space navigation lighting due to its advantages such as high efficiency and environmental friendliness. Currently, commercially available phosphor encapsulation materials are epoxy resin or silicon, which have relatively low heat resistance and thermal conductivity (0.1~0.4 W / m²). -1 K -1 High temperatures and prolonged exposure can cause yellowing and aging, leading to color temperature and color coordinate shifts in the device. Currently, methods using high thermal conductivity (9.0~13.0 W / m²) have been proposed. -1 K -1 Remote encapsulation of inorganic materials. Among them, Ce... 3+ Doped YAG (YAG:Ce) 3+ Phosphor ceramics (PCs) possess excellent optical and mechanical properties, making them one of the most promising materials. However, in practical applications, the lack of red light components is a fatal problem limiting their luminous quality, which severely hinders their development in the lighting field.
[0003] Typical ions with red emission peaks include Mn 2+ Mn 4+ Pr 3+ 、Sm 3+ Cr 3+ Etc. Due to rare earth ions Pr 3+ and Sm 3+ The absorption in the blue region is weak, and the emission peak is narrow, so it cannot effectively enhance the emission of red light. Meanwhile, the transition metal Cr... 3+ Mn 2+ Mn 4+ With a broad emission peak, Mn effectively enhances red light emission and is therefore widely used as a red luminescent activator ion in inorganic luminescent materials. While there are reports of other transition metal ions such as Cu, Ni, Co, and Ti successfully doping into YAG garnet matrices, this is not the mainstream approach. Mn is particularly effective in supplementing red light components and improving white light sources. 2+ It is currently the most widely studied and effective transition metal luminescent ion. However, when luminescent ions are co-doped, concentration quenching and a decrease in luminescence intensity are inevitable.
[0004] In most fluorescent ceramics that employ the strategy of increasing new luminescent centers, literature ( Red-emitting YAG:Ce, Mn transparent ceramics for warm WLEDs applicationThe YAG:Ce,Mn fluorescent ceramic reported by Ling et al. exhibits broadband red light emission, but this fluorescent ceramic shows limited red light emission in Mn. 2+ Severe concentration quenching occurred after doping. CN113087527A discloses an Eu... 3+ An activated red transparent fluorescent ceramic and its preparation method were developed, but the fluorescent material has a narrow emission spectrum and low emission intensity, making it unsuitable for use in high-power LEDs / LDs devices. Summary of the Invention
[0005] One objective of this invention is to provide an anomalous concentration quenching red fluorescent ceramic, which has the advantages of high emission intensity and sufficient red light component.
[0006] The second objective of this invention is to provide a method for preparing the above-mentioned anomalous concentration quenching red fluorescent ceramic, which is prepared by a very simple high-temperature solid-state sintering method, with short preparation time, low cost, and suitable for industrial production.
[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:
[0008] In a first aspect, the present invention provides an anomalous concentration quenching red fluorescent ceramic, the molecular formula of which is Mg 2- x Y 1.93 Al2Si2O 12 0.07Ce 3+ , x Mn 2+ ,in x For Mn 2+ Molar percentage of Mg-doped sites, 0 < x ≤0.05.
[0009] The fluorescent ceramic, when excited by blue light at a wavelength of around 460 nm, emits bright, broadband red light near 618 nm, and the fluorescent ceramic exhibits Mn... 2+ When the doping concentration is 0.01 ≤ x ≤ 0.05, a significant anomalous concentration quenching phenomenon occurs, i.e., Mn 2+ The entry of ions reduces Ce 2+ The number of quenching centers enhanced Ce 3+ The emission intensity of the ions causes an anomalous emission intensity in the overall fluorescent ceramic. When Mn 2+ When the doping concentration is 0.05, the emission intensity of the fluorescent ceramic is 1.79 times that when the doping concentration is 0.01.
[0010] Secondly, the present invention provides a method for preparing the above-mentioned anomalous concentration quenching red fluorescent ceramic, which employs a solid-state reaction sintering method and includes the following steps:
[0011] (1) Using Y2O3, Al2O3, MgO, SiO2, CeO2 and MnCO3 as raw material powders, according to the molecular formula Mg 2- x Y 1.93 Al2Si2O 12 0.07Ce 3+ , x Mn 2+ Weigh each raw material according to the stoichiometric ratio of the corresponding elements, where x For Mn 2+ Molar percentage of Mg-doped sites, 0 < x ≤0.05;
[0012] (2) After weighing the raw material powder and dispersant polyetherimide, add anhydrous ethanol, ball mill and mix, dry and sieve the resulting slurry, and then place the mixed powder in a muffle furnace for calcination;
[0013] (3) The calcined powder is placed in a mold and dry-pressed, and then cold isostatically pressed to obtain a green blank with a relative density of 50%~55%.
[0014] (4) Vacuum sinter the green blank pressed in step (3), cool it to room temperature, and then put the ceramic into a high-temperature muffle furnace for annealing. Finally, polish the ceramic to obtain the red fluorescent ceramic.
[0015] Preferably, in step (1), the powder particle size of Y2O3, Al2O3, MgO, CeO2 and MnCO3 is 1μm~2μm, the powder particle size of SiO2 is 4μm~5μm, and the purity of all is above 99.99%.
[0016] Preferably, in step (2), the amount of the dispersant polyetherimide added is 0.8~1wt.% of the total mass of the raw material powder, and the mass ratio of the total mass of the raw material powder to anhydrous ethanol is 1:1.5~3.
[0017] Preferably, in step (2), the ball milling speed is 160~200 rpm and the ball milling time is 15~30 h.
[0018] Preferably, in step (2), the drying temperature is 70~90℃ and the drying time is 8~12h.
[0019] Preferably, in step (2), the calcination heating regime is to raise the temperature to 600-800°C at a heating rate of 2-10°C / min at room temperature and hold it for 5-7 hours.
[0020] Preferably, in step (3), the cold isostatic pressing pressure is 150~200MPa and the holding time is 5~10min.
[0021] Preferably, in step (4), the vacuum sintering temperature is 1700~1800℃, and the holding time is 10~24h.
[0022] Preferably, in step (4), the annealing temperature is 1400~1500℃ and the annealing time is 4~10h.
[0023] Compared with the prior art, the present invention has the following beneficial effects:
[0024] (1) The fluorescent ceramic provided by this invention emits bright, broadband orange-red light near 578 nm when excited by blue light with a wavelength of around 460 nm. Furthermore, this fluorescent ceramic exhibits Mn... 2+ Doping concentration 0.01≤ x A significant anomalous concentration quenching phenomenon occurred when Mn was ≤0.05, i.e. 2+ The entry of ions reduces Ce 2+ The number of quenching centers enhanced Ce 3+ The emission intensity of the ions causes an anomalous emission intensity in the overall fluorescent ceramic. When Mn 2+ When the doping concentration is 0.05, the emission intensity of the fluorescent ceramic is 1.79 times that when the doping concentration is 0.01.
[0025] (2) This invention makes full use of Mn 2+ Doped Mg2Y2Al2Si2O 12 As a luminescent material, Mg2Y2Al2Si2O has unique advantages. 12 With abundant grid space, Mn 2+ valence state and Mg 2+ The valence states are equal and Mn 2+ Its ionic radius is close to that of Mg 2+ The ionic radius and the structural defects caused by doping effectively improve the luminescence performance of the material.
[0026] (3) Preparation of Ce in this invention 3+ and Mn 2+ Doped Mg2Y2Al2Si2O 12 The red fluorescent ceramic exhibits high efficiency in Mn extraction under blue light excitation. 2+ Broadband red light emission has excellent luminescent performance, and its preparation method is simple, quick, and environmentally friendly, making it suitable for industrial production of LED / LD devices. Attached Figure Description
[0027] Figure 1 These are the XRD patterns of the fluorescent ceramics prepared in Examples 1-5 of this invention;
[0028] Figure 2These are the emission spectra of the fluorescent ceramics prepared in Examples 1-5 of this invention under 460nm blue light excitation;
[0029] Figure 3 The intensity changes of the pyroelectric spectra of the fluorescent ceramics prepared in Examples 1-5 of this invention are shown. Detailed Implementation
[0030] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.
[0031] Unless otherwise specified, the raw material powders used in the following examples are all commercially available products. The particle size of Y2O3, Al2O3, MgO, CeO2 and MnCO3 is 1μm~2μm, and the particle size of SiO2 is 4μm~5μm.
[0032] Example 1: Preparation of Mg 1.99 Y 1.93 Al2Si2O 12 0.07Ce 3+ 0.01Mn 2+
[0033] The target product is set at 60g, based on the chemical formula Mg 1.99 Y 1.93 Al2Si2O 12 0.07Ce 3+ 0.01Mn 2+ According to the stoichiometric ratio of the corresponding raw materials, Y2O3, Al2O3, MgO, CeO2, and MnCO3, each with a purity of 99.99%, were weighed as raw material powders. These powders were mixed with 400 μL of polyetherimide dispersant, and then 80 mL of anhydrous ethanol was added. The mixture was thoroughly mixed using a planetary ball mill at 180 rpm for 20 hours. The resulting slurry was dried in an oven at 80°C for 12 hours to obtain a mixed powder. This powder was then passed through a 200-mesh sieve. After sieving twice, the mixed powder was placed in a muffle furnace and calcined at 800°C for 5 hours at a heating rate of 5°C / min. The calcined powder was then dried and pressed into a green blank in a steel mold, followed by cold isostatic pressing at 200 MPa for 5 minutes to obtain a green blank with a relative density of 50%. Vacuum sintering was then performed at 1750℃ for 10 hours. The sintered ceramic was then annealed in a high-temperature muffle furnace at 1450℃ for 4 hours. Finally, the ceramic was polished to obtain fluorescent ceramic. This fluorescent ceramic has a diameter of approximately 17 mm and a thickness of 2 mm.
[0034] The crystal structure was studied using X-ray diffraction (XRD, Model D5005, Siemens), with scanning angles ranging from 10° to 80°. The XRD patterns of the samples were obtained. Figure 1 The sample appears to be consistent with the standard card (ICSD#20090), indicating the presence of Ce at a concentration of 0.07. 3+ and Mn at a concentration of 0.01 2+ It did not have a significant impact on the crystal structure, and the resulting fluorescent ceramic was similar to Mg2Y2Al2Si2O. 12 Substances with the same structure, such as Figure 1 As shown.
[0035] The emission spectrum of this fluorescent ceramic was measured using a fluorescence spectrophotometer (OmniFluo 900, Zolix instruments). The results showed that under 460 nm blue light excitation, it emitted bright, broadband orange-red light near 578 nm, as shown in the image. Figure 2 As shown.
[0036] Example 2: Preparation of Mg 1.99 Y 1.93 Al2Si2O 12 0.07Ce 3+ 0.02Mn 2+
[0037] The target product is set at 60g, based on the chemical formula Mg 1.98 Y 1.93 Al2Si2O 12 0.07Ce 3+ 0.02Mn 2+ According to the stoichiometric ratio of the corresponding raw materials, Y₂O₃, Al₂O₃, MgO, CeO₂, and MnCO₃, each with a purity of 99.99%, were weighed as raw material powders and mixed with 400 μL of polyetherimide dispersant. Then, 80 mL of anhydrous ethanol was added, and the mixture was thoroughly mixed using a planetary ball mill at 180 rpm for 20 h. The resulting slurry was dried in an oven at 80 °C for 13 h to obtain a mixed powder. This powder was then passed through a 200-mesh sieve. After sieving twice, the mixed powder was placed in a muffle furnace and calcined at 800 °C for 5 h at a heating rate of 5 °C / min from room temperature. The calcined powder was then dried and pressed into a green blank in a steel mold, and subjected to cold isostatic pressing at 200 MPa for 5 min to obtain a green blank with a relative density of 50%. Vacuum sintering was then performed at 1750℃ for 10 hours. The sintered ceramic was then annealed in a high-temperature muffle furnace at 1450℃ for 4 hours. Finally, the ceramic was polished to obtain fluorescent ceramic. This fluorescent ceramic has a diameter of approximately 17 mm and a thickness of 2 mm.
[0038] The XRD pattern of the sample in this embodiment indicates that it is doped with Ce at a concentration of 0.07. 3+ and Mn at a concentration of 0.02 2+It did not have a significant impact on the crystal structure, and the resulting fluorescent ceramic was similar to Mg2Y2Al2Si2O. 12 Substances with the same structure, such as Figure 1 As shown.
[0039] The fluorescence spectroscopy results of this example sample show that, under 460 nm blue light excitation, it emits bright, broadband orange-red light near 578 nm with an emission intensity of Mg. 1.99 Y 1.93 Al2Si2O 12 0.07Ce 3+ 0.01Mn 2+ 1.06 times, such as Figure 2 As shown.
[0040] Example 3: Preparation of Mg 1.97 Y 1.93 Al2Si2O 12 0.07Ce 3+ 0.03Mn 2+
[0041] The target product is set at 60g, based on the chemical formula Mg 1.98 Y 1.93 Al2Si2O 12 0.07Ce 3+ 0.03Mn 2+ According to the stoichiometric ratio of the corresponding raw materials, Y2O3, Al2O3, MgO, CeO2, and MnCO3, each with a purity of 99.99%, were weighed as raw material powders. These powders were then mixed with 400 μL of polyetherimide dispersant, followed by the addition of 80 mL of anhydrous ethanol. The mixture was thoroughly mixed using a planetary ball mill at 180 rpm for 20 h. The resulting slurry was dried in an oven at 80 °C for 13 h to obtain a mixed powder. This powder was then passed through a 200-mesh sieve. After sieving twice, the powder was placed in a muffle furnace and calcined at 800 °C for 5 h at a heating rate of 5 °C / min. The calcined powder was then dried and pressed into a green blank in a steel mold, followed by cold isostatic pressing at 200 MPa for 5 min to obtain a green blank with a relative density of 50%. Vacuum sintering was then performed at 1750℃ for 10 hours. The sintered ceramic was then annealed in a high-temperature muffle furnace at 1450℃ for 4 hours. Finally, the ceramic was polished to obtain fluorescent ceramic. This fluorescent ceramic has a diameter of approximately 17 mm and a thickness of 2 mm.
[0042] The XRD pattern of the sample in this embodiment indicates that it is doped with Ce at a concentration of 0.07. 3+ and Mn at a concentration of 0.03 2+It did not have a significant impact on the crystal structure, and the resulting fluorescent ceramic was similar to Mg2Y2Al2Si2O. 12 Substances with the same structure, such as Figure 1 As shown.
[0043] The fluorescence spectroscopy results of this example sample show that, under 460 nm blue light excitation, it emits bright, broadband orange-red light near 578 nm with an emission intensity of Mg. 1.99 Y 1.93 Al2Si2O 12 0.07Ce 3+ 0.01Mn 2+ 1.08 times, such as Figure 2 As shown.
[0044] Example 4: Preparation of Mg 1.96 Y 1.93 Al2Si2O 12 0.07Ce 3+ 0.04Mn 2+
[0045] The target product is set at 60g, based on the chemical formula Mg 1.97 Y 1.93 Al2Si2O 12 0.07Ce 3+ 0.04Mn 2+ According to the stoichiometric ratio of the corresponding raw materials, Y2O3, Al2O3, MgO, CeO2, and MnCO3, each with a purity of 99.99%, were weighed as raw material powders. These powders were mixed with 400 μL of polyetherimide dispersant, and then 80 mL of anhydrous ethanol was added. The mixture was thoroughly mixed using a planetary ball mill at 180 rpm for 20 hours. The resulting slurry was dried in an oven at 80°C for 13 hours to obtain a mixed powder. This powder was then passed through a 200-mesh sieve. After sieving twice, the mixed powder was placed in a muffle furnace and calcined at 800°C for 5 hours at a heating rate of 5°C / min. The calcined powder was then dried and pressed into a green blank in a steel mold, followed by cold isostatic pressing at 200 MPa for 5 minutes to obtain a green blank with a relative density of 50%. Vacuum sintering was then performed at 1750℃ for 10 hours. The sintered ceramic was then annealed in a high-temperature muffle furnace at 1450℃ for 4 hours. Finally, the ceramic was polished to obtain fluorescent ceramic. This fluorescent ceramic has a diameter of approximately 17 mm and a thickness of 2 mm.
[0046] The XRD pattern of the sample in this embodiment indicates that it is doped with Ce at a concentration of 0.07. 3+ and Mn at a concentration of 0.04 2+It did not have a significant impact on the crystal structure, and the resulting fluorescent ceramic was similar to Mg2Y2Al2Si2O. 12 Substances with the same structure, such as Figure 1 As shown.
[0047] The fluorescence spectroscopy results of this example sample show that, under 460 nm blue light excitation, it emits bright, broadband orange-red light near 578 nm with an emission intensity of Mg. 1.99 Y 1.93 Al2Si2O 12 0.07Ce 3+ 0.01Mn 2+ 1.52 times, such as Figure 2 As shown.
[0048] Example 5: Preparation of Mg 1.96 Y 1.93 Al2Si2O 12 0.07Ce 3+ 0.05Mn 2+
[0049] The target product is set at 60g, based on the chemical formula Mg 1.95 Y 1.93 Al2Si2O 12 0.07Ce 3+ 0.05Mn 2+ According to the stoichiometric ratio of the corresponding raw materials, Y2O3, Al2O3, MgO, CeO2, and MnCO3, each with a purity of 99.99%, were weighed as raw material powders. These powders were mixed with 400 μL of polyetherimide dispersant, and then 80 mL of anhydrous ethanol was added. The mixture was thoroughly mixed using a planetary ball mill at 180 rpm for 20 hours. The resulting slurry was dried in an oven at 80°C for 13 hours to obtain a mixed powder. This powder was then passed through a 200-mesh sieve. After sieving twice, the mixed powder was placed in a muffle furnace and calcined at 800°C for 5 hours at a heating rate of 5°C / min. The calcined powder was then dried and pressed into a green blank in a steel mold, followed by cold isostatic pressing at 200 MPa for 5 minutes to obtain a green blank with a relative density of 50%. Vacuum sintering was then performed at 1750℃ for 10 hours. The sintered ceramic was then annealed in a high-temperature muffle furnace at 1450℃ for 4 hours. Finally, the ceramic was polished to obtain fluorescent ceramic. This fluorescent ceramic has a diameter of approximately 17 mm and a thickness of 2 mm.
[0050] The XRD pattern of the sample in this embodiment indicates that it is doped with Ce at a concentration of 0.07. 3+ and Mn at a concentration of 0.05 2+It did not have a significant impact on the crystal structure, and the resulting fluorescent ceramic was similar to Mg2Y2Al2Si2O. 12 Substances with the same structure, such as Figure 1 As shown.
[0051] The fluorescence spectroscopy results of this example sample show that, under 460 nm blue light excitation, it emits bright, broadband orange-red light near 578 nm with an emission intensity of Mg. 1.99 Y 1.93 Al2Si2O 12 0.07Ce 3+ 0.01Mn 2+ 1.79 times, such as Figure 2 As shown.
[0052] The trap depth and trap concentration of the fluorescent ceramics in Examples 1-5 were measured using a thermoluminescent detector (FJ-427A1, Nuclear Control, Beijing, China). The results showed that when Mn 2+ The sample with the highest defect concentration was 0.01%, and the trap concentration increased with increasing Mn concentration. 2+ As the doping concentration increases, the luminescence intensity gradually decreases, while the luminescence intensity gradually increases, such as... Figure 2 and Figure 3 As shown.
[0053] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions, and improvements made by those skilled in the art within the scope of the technology disclosed in the present invention, and within the spirit and principles of the present invention, should be covered within the scope of protection of the present invention.
Claims
1. An anomalous concentration quenching red fluorescent ceramic, characterized in that, Its molecular formula is Mg 2-x Y 1.93 Al2Si2O 12 0.07Ce 3+ , x Mn 2+ ,in x For Mn 2+ Mole percentage of Mg doped sites, 0.04 ≤ x ≤0.05; Prepared by solid-state reaction sintering, including the following steps: (1) Using Y2O3, Al2O3, MgO, SiO2, CeO2 and MnCO3 as raw material powders, according to the molecular formula Mg 2-x Y 1.93 Al2Si2O 12 0.07Ce 3+ , x Mn 2+ Weigh each raw material according to the stoichiometric ratio of the corresponding elements; (2) After weighing the raw material powder and dispersant polyetherimide, add anhydrous ethanol, ball mill and mix, dry and sieve the resulting slurry, and then place the mixed powder in a muffle furnace for calcination; (3) The calcined powder is placed in a mold and dry-pressed, and then cold isostatically pressed to obtain a green blank with a relative density of 50%~55%. (4) Vacuum sinter the green blank pressed in step (3), cool it to room temperature, then put the ceramic into a muffle furnace for annealing, and finally polish the ceramic to obtain the red fluorescent ceramic.
2. The anomalous concentration quenching red fluorescent ceramic according to claim 1, characterized in that, In step (1), the particle size of Y2O3, Al2O3, MgO, CeO2 and MnCO3 is 1μm~2μm, the particle size of SiO2 is 4μm~5μm, and the purity is above 99.99%.
3. The anomalous concentration quenching red fluorescent ceramic according to claim 1, characterized in that, In step (2), the amount of the dispersant polyetherimide added is 0.8~1wt.% of the total mass of the raw material powder, and the mass ratio of the total mass of the raw material powder to anhydrous ethanol is 1:1.5~3.
4. The anomalous concentration quenching red fluorescent ceramic according to claim 1, characterized in that, In step (2), the ball milling speed is 160~200 rpm and the ball milling time is 15~30h.
5. The anomalous concentration quenching red fluorescent ceramic according to claim 1, characterized in that, In step (2), the drying temperature is 70~90℃ and the drying time is 8~12h.
6. The anomalous concentration quenching red fluorescent ceramic according to claim 1, characterized in that, In step (2), the calcination heating regime is to raise the temperature to 600-800℃ at a heating rate of 2-10℃ / min at room temperature and hold it for 5-7 hours.
7. The anomalous concentration quenching red fluorescent ceramic according to claim 1, characterized in that, In step (3), the cold isostatic pressing pressure is 150~200MPa and the holding time is 5~10min.
8. The anomalous concentration quenching red fluorescent ceramic according to claim 1, characterized in that, In step (4), the vacuum sintering temperature is 1700~1800℃, and the holding time is 10~24h.
9. The anomalous concentration quenching red fluorescent ceramic according to claim 1, characterized in that, In step (4), the annealing temperature is 1400~1500℃ and the annealing time is 4~10h.