Near ultraviolet excited blue fluorescent powder material and application thereof

Abstract

The invention relates to the field of luminescent materials, and particularly discloses near ultraviolet excited blue fluorescent powder and application thereof, the molecular formula of the fluorescent powder material is Ca3Lu2Si3O12: xCe < 3 + >, x is the molar doping amount of Ce < 3 + >, 0 lt; and x is less than or equal to 0.10. The preparation method of the series of blue fluorescent powder adopts a high-temperature solid-phase method for synthesis, is mature in process and has large-scale production potential. The fluorescent powder shows nearly 100% internal quantum efficiency, the value of the internal quantum efficiency is as high as 99%, the fluorescent powder has broadband emission in the range of 350-600nm and has high matching degree with a blue light absorption band of a plant photosynthetic pigment, and a blue light LED device with high brightness and good matching with plant pigment absorption can be obtained by assembling the blue light material and a 365nm purple light chip.

Description

Technical Field

[0001] This invention belongs to the field of solid-state luminescent materials technology in physics, specifically relating to Ce. 3+ Activated oxide-based Ca3Lu2Si3O with calcium phosphate Ca5(PO4)2SiO4 structure 12 Blue light materials and their applications. Background Technology

[0002] Plant growth exhibits a clear selectivity to the spectrum. Photosynthetic pigments such as chlorophyll a, chlorophyll b, and carotenoids have strong absorption in the blue light band, concentrated in the range of approximately 400 nm to 500 nm. Therefore, providing a high-brightness blue light source that matches the absorption band of photosynthetic pigments is of great significance for improving the light energy utilization efficiency of plants, promoting morphogenesis, and regulating the growth cycle.

[0003] Existing blue light solutions for plant lighting mainly include direct use of blue light chips (such as InGaN chips with a center wavelength of approximately 450 nm) and conversion-type solutions using near-ultraviolet chips in conjunction with phosphors. However, existing plant lighting devices do not have a high degree of matching with the blue light absorption bands of plant photosynthetic pigments. Summary of the Invention

[0004] In view of the defects or deficiencies of the prior art, the present invention aims to provide a phosphor material that can be excited by a near-ultraviolet chip, has broadband blue emission, high quantum efficiency and good thermal stability, and a method for preparing the same, and further provides a blue LED device containing the phosphor and its application in plant lighting.

[0005] The Ce provided by this invention 3+ Doped matrix Ca3Lu2Si3O 12 It has the structure Ca5(PO4)2SiO4, and its general chemical formula is Ca3Lu2Si3O 12 : x Ce 3+ ,in x For Ce 3+ Molar doping amount, 0 < x ≤0.10. Preferred. x =0.04.

[0006] Furthermore, the phosphor material, when excited by a spectral excitation of 250nm to 400nm, has an emission spectrum range of 350nm to 600nm, with a main emission peak at 420nm.

[0007] This invention also provides a method for synthesizing the above-mentioned near-ultraviolet light-excited blue phosphor material, wherein the synthesis method employs a high-temperature solid-state synthesis method. Preferably, the high-temperature sintering reaction is carried out in an inert atmosphere and / or a reducing atmosphere.

[0008] This invention also provides an application of the above-mentioned phosphor material in the preparation of blue LED devices for plant lighting. The corresponding method for preparing the blue LED device for plant lighting includes: encapsulating the above-mentioned phosphor material with a near-ultraviolet chip to prepare the blue LED device for plant lighting. Preferably, the phosphor material is Ca3Lu2Si3O. 12 0.04Ce 3+ The near-ultraviolet chip is a 365 nm near-ultraviolet chip.

[0009] Compared to the existing Ce 3+ By doping with blue phosphor, this invention has the following advantages: (1) High quantum efficiency The Ca3Lu2Si3O of this invention 12 : x Ce 3+ Blue phosphors can achieve high-efficiency luminescence under near-ultraviolet excitation conditions, with an internal quantum efficiency (IQE) of up to 99%, which is beneficial for balancing high brightness and device photoelectric conversion efficiency.

[0010] (2) Excellent thermal stability and reliability The material of this invention is based on a stable silicate system and possesses good structural and chemical stability. Under packaging and operating temperature conditions, it can effectively suppress thermal quenching or emission decay. At an operating temperature of 150℃, Ca3Lu2Si3O 12 : x Ce 3+ The luminescence intensity remains at 84% of room temperature, thereby improving the long-term reliability and consistency of the device.

[0011] (3) Good spectral matching The phosphor of this invention exhibits broadband blue emission under near-ultraviolet light excitation, and its spectral coverage can be well matched with the blue light absorption band of plant photosynthetic pigments in the range of 400 nm to 500 nm, which is beneficial to improving the light energy utilization efficiency of plants and meeting the blue light requirements of different plant growth stages.

[0012] (4) Mature technology and easy to scale up This invention uses a high-temperature solid-state method for preparation, which simplifies the raw material system and matures the process, making it easier to achieve stable batch preparation and cost control, thus meeting the needs of industrial applications such as plant lighting. Attached Figure Description

[0013] Figure 1 Ce prepared for this invention 3+ X-ray diffraction comparison of ion-doped silicate blue phosphors; the figures show that the Ca3Lu2Si3O of this invention... 12 : x Ce3+ The diffraction peaks of the blue phosphor all match the standard peaks of the standard card (PDF#87-0453).

[0014] Figure 2 The Ca3Lu2Si3O prepared for this invention 12 0.04Ce 3+ Excitation spectrum of blue phosphor (λ) em = 420 nm) and emission spectrum (λ ex = 353 nm); the figure shows Ce 3+ Ion-doped Ca3Lu2Si3O 12 The excitation spectrum of the blue phosphor is in the range of 250 nm to 400 nm, the emission spectrum is in the range of 350 nm to 600 nm, and the main emission peak is at 420 nm.

[0015] Figure 3 The Ca3Lu2Si3O prepared for this invention 12 : x Ce 3+ ( x =0.01, 0.02, 0.03, 0.04, 0.05, 0.07 and 0.10) blue phosphor (λ) ex A comparison of emission spectral intensities at 353 nm (e.g., Ce = 353 nm); this figure shows the change in emission intensity with Ce. 3+ As the doping concentration increases, the emission intensity first increases and then decreases. x The peak intensity is highest when the doping concentration is 0.04, which is the optimal doping concentration for this system.

[0016] Figure 4 The Ca3Lu2Si3O prepared for this invention 12 0.04Ce 3+ Temperature-dependent spectra of blue phosphor; the figure shows that Ce 3+ Ion-doped Ca3Lu2Si3O 12 The emission peak intensity of blue phosphor decreases slightly with increasing temperature, but its luminescence intensity at 150℃ still remains at 84% of the room temperature luminescence intensity, demonstrating good thermal stability.

[0017] Figure 5 The Ca3Lu2Si3O prepared for this invention 12 0.04Ce 3+ Quantum yield test spectrum of blue phosphor; as shown in the figure, the present invention Ce 3+ Ion-doped Ca3Lu2Si3O 12 The internal quantum efficiency (IQE) of the blue phosphor is 99%.

[0018] Figure 6The Ca3Lu2Si3O prepared for this invention 12 0.04Ce 3+ The emission spectrum of the device assembled with blue phosphor and 365 nm blue light chip, and the absorption of plant pigments in the blue light band; the figure shows that the blue LED device prepared by the present invention has a high degree of matching with the absorption of plants in the blue light band. Specific implementation methods Unless otherwise specified, the scientific and technical terms used in this article are intended for understanding by those skilled in the art.

[0019] The phosphor material of this invention is synthesized using a high-temperature solid-state method. Examples of the synthesis method include the following steps: Step 1: Mix the calcium salt, lutetium source, silicon source and cerium source evenly; the calcium salt is selected from calcium carbonate, calcium fluoride, calcium nitrate or calcium acetate, the lutetium source is selected from lutetium trioxide or lutetium nitrate, the silicon source is selected from silicon dioxide or silicon fluoride, and the cerium source is selected from cerium dioxide or cerium acetate. Step 2: The mixture obtained in Step 1 is reacted to prepare the product under a reducing mixed atmosphere (such as 95% N2 and 5% H2 by volume) and high temperature conditions, consisting of an inert gas and hydrogen. The high temperature conditions are: heating to 1350℃-1500℃ at a rate of 3-9℃ per minute, and then maintaining the temperature at 1350℃-1500℃ for 3-6 hours.

[0020] The following are several specific examples of Ca3Lu2Si3O 12 Examples of luminescent material preparation based on a matrix are provided to further explain the technical solution of the present invention.

[0021] Example 1: This embodiment describes the solid-state preparation of blue light-emitting fluorescent material Ca3Lu2Si3O. 12 0.01Ce 3+ The specific preparation process is as follows: molar ratio Ca 2+ Lu 3+ Si 4+ Ce 4+ Weigh the raw materials CaF2 (AR) 0.2340 g, Lu2O3 (AR) 0.3940 g, SiO2 (AR) 0.1802 g, and C6H9CeO6 (AR) 0.0095 g in a stoichiometric ratio of 3:1.99:3:0.01. Place the raw materials in an agate mortar, add 3 ml of anhydrous ethanol, and grind for 15 minutes to mix them evenly. Then place them in an oven to dry. After the raw material mixture is dried, it is placed in a graphite crucible and put into a muffle furnace. The temperature is increased to 1450°C at a rate of 3°C per minute and maintained for 4 hours. Finally, it is taken out after natural cooling to room temperature and ground to obtain the product.

[0022] Figure 1 The Ca3Lu2Si3O in this embodiment 12 0.01Ce 3+ XRD patterns.

[0023] Figure 3 The Ca3Lu2Si3O in this embodiment 12 0.01Ce 3+ The emission spectrum.

[0024] Example 2: This embodiment describes the solid-state preparation of blue light-emitting fluorescent material Ca3Lu2Si3O. 12 0.02Ce 3+ The specific preparation process is as follows: molar ratio Ca 2+ Lu 3+ Si 4+ Ce 4+ Weigh the raw materials Ca(NO3)2 (AR) 0.4922 g, Lu2O3 (AR) 0.3900 g, SiF4 (AR) 0.3122 g, and CeO2 (AR) 0.0068 g in a stoichiometric ratio of 3:1.98:3:0.02. Place the raw materials in an agate mortar, add 5 ml of anhydrous ethanol, and grind for 20 minutes to mix them evenly. Then place them in an oven to dry. After the raw material mixture is dried, it is placed in a graphite crucible and put into a muffle furnace. The temperature is increased to 1500°C at a rate of 7°C per minute and maintained for 3 hours. Finally, it is taken out after naturally cooling to room temperature and ground to obtain the product.

[0025] Figure 1 The Ca3Lu2Si3O in this embodiment 12 0.02Ce 3+ XRD patterns.

[0026] Figure 3 The Ca3Lu2Si3O in this embodiment 12 0.02Ce 3+ The emission spectrum.

[0027] Example 3: This embodiment describes the solid-state preparation of blue light-emitting fluorescent material Ca3Lu2Si3O. 12 0.03Ce 3+ The specific preparation process is as follows: molar ratio Ca 2+ Lu 3+ Si 4+ Ce 4+ Weigh the raw materials CaCO3 (AR) 0.3003 g, Lu2O3 (AR) 0.3860 g, SiF4 (AR) 0.3122 g, and C6H9CeO6 (AR) 0.0285 g in a stoichiometric ratio of 3:1.97:3:0.03. Place the raw materials in an agate mortar, add 3 ml of anhydrous ethanol, and grind for 15 minutes to mix them evenly. Then place them in an oven to dry. After the raw material mixture is dried, it is placed in a graphite crucible and put into a muffle furnace. The temperature is increased to 1350°C at a rate of 6°C per minute and maintained for 6 hours. Finally, it is naturally cooled to room temperature and then taken out and ground to obtain the product.

[0028] Figure 1 The Ca3Lu2Si3O in this embodiment 12 0.03Ce 3+ XRD patterns.

[0029] Figure 3 The Ca3Lu2Si3O in this embodiment 12 0.03Ce 3+ The emission spectrum.

[0030] Example 4: This embodiment describes the solid-state preparation of blue light-emitting fluorescent material Ca3Lu2Si3O. 12 0.04Ce 3+ The specific preparation process is as follows: molar ratio Ca 2+ Lu 3+ Si 4+ Ce 4+ Weigh the raw materials C4H6CaO4 (AR) 0.4744 g, Lu2O3 (AR) 0.3820 g, SiO2 (AR) 0.1802 g, and CeO2 (AR) 0.0138 g in a stoichiometric ratio of 3:1.96:3:0.04. Place the raw materials in an agate mortar, add 6 ml of anhydrous ethanol, and grind for 30 minutes to mix them evenly. Then place them in an oven to dry. After the raw material mixture is dried, it is placed in a graphite crucible and put into a muffle furnace. The temperature is increased to 1450°C at a rate of 5°C per minute and maintained for 6 hours. Finally, it is taken out after natural cooling to room temperature and ground to obtain the product.

[0031] Figure 1 The Ca3Lu2Si3O in this embodiment 120.04Ce 3+ XRD patterns.

[0032] Figure 2 The Ca3Lu2Si3O in this embodiment 12 0.04Ce 3+ The excitation and emission spectra of the phosphor show that it has broadband excitation and emission characteristics.

[0033] Figure 3 The Ca3Lu2Si3O in this embodiment 12 0.04Ce 3+ The emission spectrum.

[0034] Figure 4 This embodiment uses Ca3Lu2Si3O 12 0.04Ce 3+ The temperature-dependent spectrum of the phosphor shows that when the temperature rises to 150℃, the luminescence intensity of the phosphor remains at 84% of its room temperature intensity. This data proves that the material has an extremely low thermal quenching effect under high-temperature operating conditions, which can ensure the reliability and color stability of high-power LED devices during long-term operation.

[0035] Figure 5 The Ca3Lu2Si3O in this embodiment 12 0.04Ce 3+ The quantum yield test spectrum of the phosphor shows that the phosphor has an internal quantum efficiency (IQE) of up to 99% under near-ultraviolet light excitation. This conversion efficiency of nearly 100% means that the material can greatly reduce energy loss, thereby significantly improving the brightness and photoelectric conversion efficiency of the final LED device.

[0036] A blue LED device for plant lighting was prepared by assembling the phosphor with a 365 nm near-ultraviolet chip using an LED packaging process (mixing phosphor with silicone and coating it on the chip surface). Figure 6 The Ca3Lu2Si3O in this embodiment 12 0.04Ce 3+ The emission spectrum of the blue LED device for plant lighting assembled with phosphor and 365 nm blue light chip and the absorption spectrum of chlorophyll a / b in the blue light region are shown in the figure. As can be seen from the figure, the broadband blue light emission characteristics of the phosphor (covering 350 nm to 600 nm) highly overlap with the absorption peaks of chlorophyll a / b, with an overlap of 99% with chlorophyll a and 83% with chlorophyll b. This clearly demonstrates that the spectrum of the device prepared by this material can effectively cover the blue light region required for plant photosynthesis, confirming its application potential in the field of plant lighting.

[0037] Example 5: This embodiment describes the solid-state preparation of blue light-emitting fluorescent material Ca3Lu2Si3O. 12 0.05Ce 3+ The specific preparation process is as follows: molar ratio Ca 2+ Lu 3+ Si 4+ Ce 4+ Weigh the raw materials C4H6CaO4 (AR) 0.4744 g, Lu2O3 (AR) 0.3780 g, SiF4 (AR) 0.3122 g, and CeO2 (AR) 0.0172 g in a stoichiometric ratio of 3:1.95:3:0.05. Place the raw materials in an agate mortar, add 5 ml of anhydrous ethanol, and grind for 20 minutes to mix them evenly. Then place them in an oven to dry. After the raw material mixture is dried, it is placed in a graphite crucible and put into a muffle furnace. The temperature is increased to 1500°C at a rate of 4°C per minute and maintained for 3 hours. Finally, it is taken out after naturally cooling to room temperature and ground to obtain the product.

[0038] Figure 1 The Ca3Lu2Si3O in this embodiment 12 0.05Ce 3+ XRD patterns.

[0039] Figure 3 The Ca3Lu2Si3O in this embodiment 12 0.05Ce 3+ The emission spectrum.

[0040] Example 6: This embodiment describes the solid-state preparation of blue light-emitting fluorescent material Ca3Lu2Si3O. 12 0.07Ce 3+ The specific preparation process is as follows: molar ratio Ca 2+ Lu 3+ Si 4+ Ce 4+ Weigh the raw materials CaF2 (AR) 0.2340 g, Lu2O3 (AR) 0.3700 g, SiF4 (AR) 0.3122 g, and CeO2 (AR) 0.0240 g in a stoichiometric ratio of 3:1.93:3:0.07. Place the raw materials in an agate mortar, add 5 ml of anhydrous ethanol, and grind for 20 minutes to mix them evenly. Then place them in an oven to dry. After the raw material mixture is dried, it is placed in a graphite crucible and put into a muffle furnace. The temperature is increased to 1400°C at a rate of 8°C per minute and maintained for 5 hours. Finally, it is taken out after natural cooling to room temperature and ground to obtain the product.

[0041] Figure 1 The Ca3Lu2Si3O in this embodiment 12 0.07Ce 3+ XRD patterns.

[0042] Figure 3 The Ca3Lu2Si3O in this embodiment 12 0.07Ce 3+ The emission spectrum.

[0043] Example 7: This embodiment describes the solid-state preparation of blue light-emitting fluorescent material Ca3Lu2Si3O. 12 0.10Ce 3+ The specific preparation process is as follows: molar ratio Ca 2+ Lu 3+ Si 4+ Ce 4+ Weigh the raw materials CaCO3 (AR) 0.3003 g, Lu2O3 (AR) 0.3580 g, SiF4 (AR) 0.3122 g, and CeO2 (AR) 0.0340 g in a stoichiometric ratio of 3:1.9:3:0.1. Place the raw materials in an agate mortar, add 6 ml of anhydrous ethanol, and grind for 30 minutes to mix them evenly. Then place them in an oven to dry. After the raw material mixture is dried, it is placed in a graphite crucible and put into a muffle furnace. The temperature is increased to 1450°C at a rate of 9°C per minute and maintained for 4 hours. Finally, it is naturally cooled to room temperature and then taken out and ground to obtain the product.

[0044] Figure 1 The Ca3Lu2Si3O in this embodiment 12 0.10Ce 3+ XRD patterns.

[0045] Figure 3 The Ca3Lu2Si3O in this embodiment 12 0.10Ce 3+ The emission spectrum.

[0046] Example 8: This embodiment describes the solid-state preparation of blue light-emitting fluorescent material Ca3Lu2Si3O. 12 0.01Ce 3+ The specific preparation process is as follows: molar ratio Ca 2+ Lu 3+ Si 4+ Ce 4+Weigh 0.2340 g of raw materials CaF2 (AR) and H2LuN3O in a stoichiometric ratio of 3:1.99:3:0.01. 10 (AR) 0.9288 g, SiF4(AR) 0.3122 g, CeO2(AR) 0.0034 g. Place the raw materials in an agate mortar, add 6 ml of anhydrous ethanol and grind for 30 minutes to mix them evenly, and then put them in an oven to dry. After the raw material mixture is dried, it is placed in a graphite crucible and put into a muffle furnace. The temperature is increased to 1500°C at a rate of 6°C per minute and maintained for 3 hours. Finally, it is naturally cooled to room temperature and then taken out and ground to obtain the product.

[0047] Example 9: This embodiment describes the solid-state preparation of blue light-emitting fluorescent material Ca3Lu2Si3O. 12 0.07Ce 3+ The specific preparation process is as follows: molar ratio Ca 2+ Lu 3+ Si 4+ Ce 4+ Weigh the raw materials CaCO3 (AR) 0.3003 g, Lu2O3 (AR) 0.3700 g, SiO2 (AR) 0.1802 g, and CeO2 (AR) 0.0240 g in a stoichiometric ratio of 3:1.93:3:0.07. Place the raw materials in an agate mortar, add 6 ml of anhydrous ethanol, and grind for 30 minutes to mix them evenly. Then place them in an oven to dry. After the raw material mixture is dried, it is placed in a graphite crucible and put into a muffle furnace. The temperature is increased to 1350°C at a rate of 6°C per minute and maintained for 6 hours. Finally, it is naturally cooled to room temperature and then taken out and ground to obtain the product.

[0048] Example 10: This embodiment describes the solid-state preparation of blue light-emitting fluorescent material Ca3Lu2Si3O. 12 0.01Ce 3+ The specific preparation process is as follows: molar ratio Ca 2+ Lu 3+ Si 4+ Ce 4+Weigh the raw materials CaCO3 (AR) 0.3003 g, Lu2O3 (AR) 0.3940 g, SiO2 (AR) 0.1802 g, and CeO2 (AR) 0.0034 g in a stoichiometric ratio of 3:1.99:3:0.01. Place the raw materials in an agate mortar, add 3 ml of anhydrous ethanol, and grind for 15 minutes to mix them evenly. Then place them in an oven to dry. After the raw material mixture is dried, it is placed in a graphite crucible and put into a muffle furnace. The temperature is increased to 1450°C at a rate of 8°C per minute and maintained for 4 hours. Finally, it is naturally cooled to room temperature and then taken out and ground to obtain the product.

[0049] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A near-ultraviolet light-excited blue phosphor material, characterized in that, The chemical formula of the phosphor material is Ca3Lu2Si3O 12 : x Ce 3+ , Among them, among them, x For Ce 3+ molar concentration, 0 < x ≤0.

10.

2. The near-ultraviolet light-excited blue phosphor material according to claim 1, characterized in that, x =0.04。 3. The near-ultraviolet light-excited blue phosphor material according to any one of claims 1 to 2, characterized in that, The phosphor material emits a spectrum ranging from 350 nm to 600 nm under spectral excitation at 250 nm to 400 nm, with a main emission peak at 420 nm.

4. The method for synthesizing the near-ultraviolet light-excited blue phosphor material according to claim 1, characterized in that, The synthesis method employs a high-temperature solid-phase synthesis method.

5. The synthesis method as described in claim 4, characterized in that, The high-temperature sintering reaction is carried out in an inert atmosphere and / or a reducing atmosphere.

6. The application of the phosphor material described in claim 1 in the preparation of blue LED devices for plant lighting.

7. A blue LED device for plant lighting, characterized in that, The device fabrication method includes: encapsulating the phosphor material described in claim 1 or 2 with a near-ultraviolet chip.

8. The blue LED device for plant lighting according to claim 7, characterized in that, The phosphor material is Ca3Lu2Si3O 12 0.04Ce 3+ The near-ultraviolet chip is a 365 nm near-ultraviolet chip.

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