Blue light excited red light fluorescent material, LED device and fluorescent ceramic

Abstract

The application relates to a blue-light-excited red-light fluorescent material, an LED device and a fluorescent ceramic. 2‑x MgNbO 6.5 :xEu 3+ , wherein 0.01<=x<=0.1. A preparation method comprises the following steps: weighing lanthanum oxide, magnesium oxide, niobium oxide and europium oxide raw materials according to a stoichiometric ratio, grinding and uniformly mixing; uniformly mixed powder is subjected to high-temperature sintering in a muffle furnace, and the red-light fluorescent material can be obtained after cooling to room temperature. Compared with the prior art, the novel oxide-based red fluorescent powder prepared by the application can emit a central wavelength of 616nm under 465nm blue light excitation, and can be used for a white light LED light-emitting device and a fluorescent ceramic.

Description

Technical Field

[0001] This invention belongs to the field of fluorescent materials technology, and in particular relates to a blue light-excited red fluorescent material, LED devices, and fluorescent ceramics. Background Technology

[0002] White light-emitting diodes (W-LEDs) are widely used in solid-state lighting due to their excellent luminous efficiency, long lifespan, environmental friendliness, and stability. Currently, commercial white LEDs mainly rely on blue LED chips and Y3Al5O4. 12 :Ce 3+ (YAG:Ce 3+ The system was prepared using a combination of yellow phosphors. However, due to insufficient red light component, its emission spectrum is limited in the red light wavelength range, resulting in a high correlated color temperature (CCT) (>4500K) and a low color rendering index (Ra) (<75), which makes it difficult to meet the requirements of high-quality lighting and full-spectrum applications.

[0003] Red phosphors play a significant role in optimizing the spectrum of white LEDs and improving color rendering performance. Traditional red phosphors, such as nitride phosphors, can improve color rendering, but their preparation requires harsh conditions, such as high pressure (~9 atm) and high temperature (~2000℃). This results in high equipment requirements, complex processes, and high costs, limiting their large-scale application.

[0004] The luminescent properties of phosphors are largely influenced by the crystal structure of the matrix material and the chemical environment of the dopant ions. Doped Mn 4+ While fluoride phosphors possess some red light emission capability, their chemical stability is poor, and their preparation requires the use of highly corrosive anhydrous HF, posing safety and environmental concerns. Eu... 3+ As an important rare-earth luminescent ion, due to its 4f electronic transition characteristics, it can produce strong red light emission in specific crystal field environments. Its main emission peak is usually located in the 610-620 nm range, making it suitable for compensating for the lack of red light in the spectrum of blue-excited LEDs. Compared to Eu... 2+ The broadband transmission characteristics of Eu 3+ The emission spectrum exhibits a narrow band characteristic, with stable emission peak positions that are closely related to the crystal structure of the matrix material. However, commercially available Eu-doped materials... 3+ Red phosphors such as CaMoO4:Eu 3+ and Y2O3:Eu 3+ The luminous intensity is not high, and the luminous performance still needs further improvement, thus limiting its application in the fabrication of white LED devices. Y2O3:Eu 3+ Its high cost is due to its pure rare earth composition. Furthermore, CN102585831A discloses an Eu... 3+Activated fluoromolybdate red phosphor, chemical formula NaR 4-4x Eu 4x [Mo3O 15 The activating ion of this red phosphor is europium ion (Eu). 3+ Its excitation spectrum is in the near-ultraviolet region of 350–400 nm and the blue light region around 465 nm. However, this red phosphor cannot be adapted to blue light excitation chips to fabricate LED devices; and the sintering temperature is relatively low, making this red phosphor and CaMoO4:Eu... 3+ The maximum preparation temperature of these phosphors does not exceed 1200℃, making it impossible to further prepare fluorescent ceramics and limiting their application in the preparation of fluorescent ceramics.

[0005] Therefore, it is necessary to develop an Eu-doped material that is physically and chemically stable, inexpensive, and can be efficiently excited by blue light. 3+ Oxide-based red phosphors are of great significance for promoting the development of white LEDs, solar-like LEDs, and fluorescent ceramics. Summary of the Invention

[0006] The purpose of this invention is to overcome the limitations of existing Eu-doped materials. 3+ To address the shortcomings of oxide-based red phosphors, such as the need to improve their luminescence performance and their difficulty in being used to prepare white LED devices and fluorescent ceramics, this paper proposes a blue-light-excited red fluorescent material, LED device, and fluorescent ceramic.

[0007] The objective of this invention can be achieved through the following technical solutions:

[0008] This invention first provides a blue light-excited red fluorescent material, characterized in that the chemical formula of the red fluorescent material is La. 2-x MgNbO 6.5 :xEu 3+ , where 0.01≤x≤0.1.

[0009] Furthermore, the excitation spectrum of the red fluorescent material is in the range of 200-550 nm.

[0010] Furthermore, the central excitation wavelength of the red fluorescent material is 465 nm.

[0011] Furthermore, the emission spectrum of the red fluorescent material is in the range of 550-720 nm.

[0012] Furthermore, the central emission wavelength of the red fluorescent material is 616 nm.

[0013] Further, x is 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09 or 0.1.

[0014] The blue-light-excited red fluorescent material of this invention emits wavelengths ranging from 550 to 720 nm and can effectively absorb light in the 200-550 nm wavelength range. It is perfectly compatible with existing blue light chips and can emit positive red light with a center wavelength of 616 nm under 465 nm blue light excitation. The matrix material of the red fluorescent material is La₂MgNbO₂. 6.5 The selection stems from its unique advantages in crystal field modulation and structural stability. By constructing a three-dimensional interpenetrating network (space group Fm-3m) of [LaO8] dodecahedrons and [NbO6] octahedrons, a strong localized crystal field is formed, significantly enhancing the Eu crystal. 3+ The ff transition efficiency is improved while suppressing nonradiative energy loss caused by lattice vibrations. La 3+ With Eu 3+ The ionic radius matching (Δr = 8.1%) follows the Hume-Rothery solid solution rule, achieving equivalent substitution (without charge compensation), thus maintaining lattice symmetry and improving doping efficiency. Mg 2+ and Nb 5+ The co-occupancy of B sites forms a stable octahedral coordination, and its synergistic effect optimizes the band structure, making the excitation spectrum (465nm) perfectly matched with the blue LED chip.

[0015] Furthermore, the red fluorescent material is prepared by the following steps: weighing lanthanum oxide, magnesium oxide, niobium oxide and europium oxide raw materials according to stoichiometric ratio, grinding and mixing them evenly; sintering the evenly mixed powder at high temperature in a muffle furnace, and then cooling it to room temperature to obtain the red fluorescent material.

[0016] Furthermore, the grinding and mixing time is 20-50 minutes.

[0017] Furthermore, the high-temperature sintering is carried out in an air atmosphere.

[0018] Furthermore, the high-temperature sintering temperature is 1200-1600℃, preferably 1400-1500℃.

[0019] Furthermore, the high-temperature sintering time is 6-10 hours, preferably 8 hours.

[0020] Furthermore, the cooling rate is 1-5℃ / min, preferably 3℃ / min.

[0021] The present invention also provides an LED device comprising a red fluorescent material excited by blue light.

[0022] Furthermore, the LED device is any one of a white LED device, a solar-like LED device, or a full-spectrum white LED device.

[0023] Furthermore, the white LED device is made by encapsulating red fluorescent material and a 465nm blue LED chip.

[0024] Furthermore, the color rendering index (CRI) of the white LED device is not less than 80. The higher the CRI (Ra), the stronger the ability of the light source to reproduce the colors of objects. Therefore, the high-Ra white LED device of this invention can better reproduce the true colors of objects and is suitable for scenarios requiring high color fidelity.

[0025] Furthermore, the correlated color temperature of the white LED device is no higher than 4500K, making it suitable for warm and comfortable lighting environments.

[0026] The present invention also provides a fluorescent ceramic comprising a red fluorescent material excited by blue light.

[0027] Further, the fluorescent ceramic is prepared from the following raw material components in parts by weight: 90-110 parts of red fluorescent material, 2-3 parts of monomer, 0.1-0.15 parts of crosslinking agent, 1.3-3.75 parts of dispersant, 12-25 parts of solvent, 0.8-2 parts of catalyst, and 0.2-1 parts of initiator.

[0028] Furthermore, the monomer is N,N-dimethylacrylamide.

[0029] Furthermore, the crosslinking agent is N,N'-methylenebisacrylamide.

[0030] Furthermore, the dispersant is ammonium polyacrylate.

[0031] Furthermore, the catalyst is N,N,N,N,-tetramethylethylenediamine.

[0032] Furthermore, the initiator is ammonium persulfate.

[0033] Furthermore, the fluorescent ceramic is prepared using the following method:

[0034] S1: The monomer, dispersant and crosslinking agent are added to the solvent and mixed to obtain a premix; then red fluorescent material is added to the premix in batches and ball milled to obtain a precursor slurry;

[0035] S2: Add a catalyst to the precursor slurry and ball mill it to obtain a molding slurry; add an initiator to the molding slurry and then perform molding and gelation to obtain a preform;

[0036] S3: Dry the green body, then sinter it at 1200-1700℃ for 12-24h, and cool it to room temperature after sintering to obtain the fluorescent ceramic.

[0037] Furthermore, in step S1, the red fluorescent material is added in three batches, and ball milling is performed for 4-12 hours after each addition.

[0038] Furthermore, in step S2, the ball milling time is 0.5-1.5 hours.

[0039] Further, in step S2, an initiator is added dropwise to the slurry for molding, and after rapid stirring for 0.5-3 minutes, the mold prepared in advance is used for molding immediately. The molding operation is completed within 0.5-4 minutes depending on the amount of initiator and catalyst.

[0040] Furthermore, in step S3, the mold containing the blank is first placed at room temperature to remove some of the water and then solidified and shaped. The blank is then placed in an oven for drying. After 90% of the moisture is removed, the drying process is complete.

[0041] Furthermore, in step S3, the drying temperature is 60-90℃ and the drying time is 24-72h.

[0042] Furthermore, in step S3, the cooling rate is 1-5℃ / min.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] (1) The novel oxide-based red phosphor La prepared by this invention 2-x MgNbO 6.5 :xEu 3+ It can emit positive red light with a center wavelength of 616nm when excited by 465nm blue light, which is similar to existing Eu... 3+ Compared to red phosphors, doped red phosphors have higher fluorescence intensity and stability, and can be well matched with existing blue phosphor chips for packaging and fabrication of white LED light-emitting devices.

[0045] (2) The emission wavelength of the blue light-excited fluorescent material of the present invention includes 550-720nm, and it can effectively absorb light in the wavelength range of 200-550nm. It can be well matched with existing blue light chips to meet the needs of the commercial market and is suitable for applications such as white LED, solar-like LED, and full-spectrum LED. It provides a new solution for improving the continuity of LED spectrum and color rendering performance.

[0046] (3) The blue light-excited red fluorescent material prepared by the present invention has the advantage of stable physicochemical properties. It can be prepared by high-temperature solid-state reaction method. It has the characteristics of simple preparation process and high purity of the prepared sample. It can be used as a good candidate material for the widespread application of white LED and has a wide application prospect.

[0047] (4) The red fluorescent material of the present invention, compared with similar CaMoO4:Eu 3+ Red phosphors, synthesized at 1450℃, are more suitable for high-temperature preparation into fluorescent ceramics or fluorescent transparent ceramics; compared to pure rare-earth Y2O3:Eu... 3+ It offers greater cost advantages. Furthermore, the red fluorescent material of this invention exhibits higher spectral intensity and a broader spectrum under blue light excitation, higher quantum efficiency, and superior luminescence performance, durability, and stability compared to traditional Eu. 3+ It is doped with red phosphor.

[0048] (5) The white LED device prepared by packaging the red phosphor of the present invention with a 465nm blue LED chip and the commercial yellow phosphor (YAG:Ce) 3+ Compared to packaged LEDs, it has a higher color rendering index and a lower correlated color temperature. Its excellent luminous performance can better reproduce the true color of objects and is suitable for scenarios that require high color fidelity as well as warm and comfortable lighting environments.

[0049] (6) Compared with existing technologies, the fluorescent ceramics prepared from the blue-light-excited red-light fluorescent material provided by this invention have lower thermal conductivity than traditional resin and silicone encapsulation materials, which are prone to thermal exhaustion of phosphors due to high temperatures under high-energy excitation. In contrast, this invention uses La... 2-x MgNbO 6.5 :xEu 3+ High-density fluorescent ceramics prepared using powder and gel casting technology significantly improve thermal conductivity and thermal stability. This design effectively enhances heat dissipation, reduces temperature rise caused by high-energy excitation, and slows down phosphor performance degradation, thereby significantly extending device lifespan. This advantage is particularly prominent in high-power lighting and display applications, providing strong support for high-reliability devices. Attached Figure Description

[0050] Figure 1 The images show the photoexcitation-emission spectra of the red fluorescent materials prepared in Example 1 and Comparative Examples 1 and 2.

[0051] Figure 2 The XRD diffraction pattern of the red fluorescent material prepared in Example 1 is shown below.

[0052] Figure 3The photoexcitation-emission spectra of the red fluorescent materials prepared in Examples 1, 5, and 10 are shown.

[0053] Figure 4 Electroluminescence spectra of the white LED devices packaged in Example 1(a) and Comparative Example 3(b), respectively;

[0054] Figure 5 Photoexcitation-emission spectra of fluorescent ceramics prepared from the red fluorescent material of Example 9 and the red fluorescent material of Application Example 2. Detailed Implementation

[0055] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0056] Unless otherwise specified, the reagents, methods, instruments, and equipment used in this invention are conventional in the art. Unless otherwise specified, the reagents and materials used in the following examples are all commercially available.

[0057] Example 1:

[0058] This embodiment provides a blue light-excited Eu... 3+ Doped red fluorescent materials have the general formula La. 2-x MgNbO 6.5 :xEu 3+ x is 0.01. The specific preparation method is as follows:

[0059] (1) Weigh 1g of raw material powder containing La2O3, MgO, Nb2O5, and Eu2O3 (the mass ratio of each raw material is La2O3:MgO:Nb2O5:Eu2O3 = 0.6494:0.0807:0.2662:0.0035) according to the stoichiometric ratio.

[0060] (2) The obtained raw material mixture is ground in an agate mortar for 20-50 minutes. After the material is mixed evenly, the mixture is loaded into an alumina crucible and placed in a muffle furnace for calcination at 1200℃ for 6 hours in an air atmosphere. Then, it is cooled to room temperature at a rate of 3℃ / min to obtain a blue light-excited red fluorescent material.

[0061] Example 2:

[0062] This embodiment provides a blue light-excited Eu... 3+ Doped red fluorescent materials have the general formula La. 2-x MgNbO 6.5 :xEu 3+x is 0.02. The specific preparation method is as follows:

[0063] (1) Weigh 1g of raw material powder containing La2O3, MgO, Nb2O5, and Eu2O3 (the mass ratio of each raw material is La2O3:MgO:Nb2O5:Eu2O3 = 0.6460:0.0807:0.2661:0.0070) according to the stoichiometric ratio.

[0064] (2) The obtained raw material mixture is ground in an agate mortar for 20-50 minutes. After the material is mixed evenly, the mixture is loaded into an alumina crucible and placed in a muffle furnace for calcination at 1250℃ for 6 hours in an air atmosphere. Then, it is cooled to room temperature at a rate of 3℃ / min to obtain a blue light-excited red fluorescent material.

[0065] Example 3:

[0066] This embodiment provides a blue light-excited Eu... 3+ Doped red fluorescent materials have the general formula La. 2-x MgNbO 6.5 :xEu 3+ x is 0.03. The specific preparation method is as follows:

[0067] (1) Weigh 1g of raw material powder containing La2O3, MgO, Nb2O5, and Eu2O3 (the mass ratio of each raw material is La2O3:MgO:Nb2O5:Eu2O3 = 0.6426:0.0807:0.2661:0.0105) according to the stoichiometric ratio.

[0068] (2) The obtained raw material mixture is ground in an agate mortar for 20-50 minutes. After the material is mixed evenly, the mixture is loaded into an alumina crucible and placed in a muffle furnace for calcination at 1300℃ for 7 hours in an air atmosphere. Then, it is cooled to room temperature at a rate of 3℃ / min to obtain a blue light-excited red fluorescent material.

[0069] Example 4:

[0070] This embodiment provides a blue light-excited Eu... 3+ Doped red fluorescent materials have the general formula La. 2-x MgNbO 6.5 :xEu 3+ x is 0.04. The specific preparation method is as follows:

[0071] (1) Weigh 1g of raw material powder containing La2O3, MgO, Nb2O5, and Eu2O3 (the mass ratio of each raw material is La2O3:MgO:Nb2O5:Eu2O3 = 0.6391:0.0806:0.2660:0.0140) according to the stoichiometric ratio.

[0072] (2) The obtained raw material mixture is ground in an agate mortar for 20-50 minutes. After the material is mixed evenly, the mixture is loaded into an alumina crucible and placed in a muffle furnace for calcination at 1350℃ for 7 hours in an air atmosphere. Then, it is cooled to room temperature at a rate of 3℃ / min to obtain a blue light-excited red fluorescent material.

[0073] Example 5:

[0074] This embodiment provides a blue light-excited Eu... 3+ Doped red fluorescent materials have the general formula La. 2-x MgNbO 6.5 :xEu 3+ x is 0.05. The specific preparation method is as follows:

[0075] (1) Weigh 1g of raw material powder containing La2O3, MgO, Nb2O5, and Eu2O3 (the mass ratio of each raw material is La2O3:MgO:Nb2O5:Eu2O3 = 0.6357:0.0806:0.2659:0.0176) according to the stoichiometric ratio.

[0076] (2) The obtained raw material mixture is ground in an agate mortar for 20-50 minutes. After the material is mixed evenly, the mixture is loaded into an alumina crucible and placed in a muffle furnace for calcination at 1400℃ for 8 hours in an air atmosphere. Then, it is cooled to room temperature at a rate of 3℃ / min to obtain a blue light-excited red fluorescent material.

[0077] Example 6:

[0078] This embodiment provides a blue light-excited Eu... 3+ Doped red fluorescent materials have the general formula La. 2-x MgNbO 6.5 :xEu 3+ x is 0.06. The specific preparation method is as follows:

[0079] (1) Weigh 1g of raw material powder containing La2O3, MgO, Nb2O5, and Eu2O3 (the mass ratio of each raw material is La2O3:MgO:Nb2O5:Eu2O3 = 0.6323:0.0806:0.2659:0.0211) according to the stoichiometric ratio.

[0080] (2) The obtained raw material mixture is ground in an agate mortar for 20-50 minutes. After the material is mixed evenly, the mixture is loaded into an alumina crucible and placed in a muffle furnace for calcination at 1450℃ for 8 hours in an air atmosphere. Then, it is cooled to room temperature at a rate of 3℃ / min to obtain a blue light-excited red fluorescent material.

[0081] Example 7:

[0082] This embodiment provides a blue light-excited Eu... 3+ Doped red fluorescent materials have the general formula La. 2-x MgNbO 6.5 :xEu 3+ x is 0.07. The specific preparation method is as follows:

[0083] (1) Weigh 1g of raw material powder containing La2O3, MgO, Nb2O5, and Eu2O3 (the mass ratio of each raw material is La2O3:MgO:Nb2O5:Eu2O3 = 0.6288:0.0806:0.2658:0.0246) according to the stoichiometric ratio.

[0084] (2) The obtained raw material mixture is ground in an agate mortar for 20-50 minutes. After the material is mixed evenly, the mixture is loaded into an alumina crucible and placed in a muffle furnace for calcination at 1500℃ for 9 hours in an air atmosphere. Then, it is cooled to room temperature at a rate of 3℃ / min to obtain a blue light-excited red fluorescent material.

[0085] Example 8:

[0086] This embodiment provides a blue light-excited Eu... 3+ Doped red fluorescent materials have the general formula La. 2-x MgNbO 6.5 :xEu 3+ x is 0.08. The specific preparation method is as follows:

[0087] (1) Weigh 1g of raw material powder containing La2O3, MgO, Nb2O5, and Eu2O3 (the mass ratio of each raw material is La2O3:MgO:Nb2O5:Eu2O3 = 0.6254:0.0805:0.2657:0.0281) according to the stoichiometric ratio.

[0088] (2) The obtained raw material mixture is ground in an agate mortar for 20-50 minutes. After the material is mixed evenly, the mixture is loaded into an alumina crucible and placed in a muffle furnace for calcination at 1550℃ for 9 hours in an air atmosphere. Then, it is cooled to room temperature at a rate of 3℃ / min to obtain a blue light-excited red fluorescent material.

[0089] Example 9:

[0090] This embodiment provides a blue light-excited Eu... 3+ Doped red fluorescent materials have the general formula La. 2-x MgNbO 6.5 :xEu 3+ x is 0.09. The specific preparation method is as follows:

[0091] (1) Weigh 1g of raw material powder containing La2O3, MgO, Nb2O5, and Eu2O3 (the mass ratio of each raw material is La2O3:MgO:Nb2O5:Eu2O3 = 0.6220:0.0805:0.2657:0.0316) according to the stoichiometric ratio.

[0092] (2) The obtained raw material mixture is ground in an agate mortar for 20-50 minutes. After the material is mixed evenly, the mixture is loaded into an alumina crucible and placed in a muffle furnace for calcination at 1600℃ for 10 hours in an air atmosphere. Then, it is cooled to room temperature at a rate of 3℃ / min to obtain a blue light-excited red fluorescent material.

[0093] Example 10:

[0094] This embodiment provides a blue light-excited Eu... 3+ Doped red fluorescent materials have the general formula La. 2-x MgNbO 6.5 :xEu 3+ x is 0.1. The specific preparation method is as follows:

[0095] (1) Weigh 1g of raw material powder containing La2O3, MgO, Nb2O5, and Eu2O3 (the mass ratio of each raw material is La2O3:MgO:Nb2O5:Eu2O3 = 0.6186:0.0805:0.2656:0.0351) according to the stoichiometric ratio.

[0096] (2) The obtained raw material mixture is ground in an agate mortar for 20-50 minutes. After the material is mixed evenly, the mixture is loaded into an alumina crucible and placed in a muffle furnace for calcination at 1600℃ for 10 hours in an air atmosphere. Then, it is cooled to room temperature at a rate of 3℃ / min to obtain a blue light-excited red fluorescent material.

[0097] Comparative Example 1:

[0098] This comparative example provides a blue light-excited Eu... 3+ Doped red phosphors have the general formula Yi 2-x O3:xEu 3+ x is 0.05. The specific preparation method is as follows:

[0099] (1) Y2O3 and Eu2O3 were selected as starting materials, Y2O3:Eu2O3=0.9615:0.0384, corresponding to x=0.05. The two materials were weighed separately, and the total mass of the raw material mixture was controlled to be 1g of mixed raw materials.

[0100] (2) Place the obtained raw material mixture in an agate mortar and grind for 20-50 minutes. After the material is mixed evenly, load the mixture into an alumina crucible. Then place the alumina crucible containing the raw material in the air and calcine at 1200℃ for 4 hours. After cooling to room temperature, the target product is obtained.

[0101] Comparative Example 2:

[0102] This comparative example provides a blue light-excited Eu... 3+ Doped red phosphors have the general formula Ca 1-x MoO4:xEu 3+ x is 0.05. The specific preparation method is as follows:

[0103] (1) Select CaCO3, MoO3 and Eu2O3 as starting materials, CaCO3:MoO3:Eu2O3=0.2854:0.5473:0.1672, corresponding to x=0.25, weigh the three materials respectively, and control the total mass of the raw material mixture to be 1g of mixed raw materials.

[0104] (2) Place the obtained raw material mixture in an agate mortar and grind for 20-50 minutes. After the material is mixed evenly, load the mixture into an alumina crucible. Then place the alumina crucible containing the raw material in the air and calcine at 1000℃ for 4 hours. After cooling to room temperature, the target product is obtained.

[0105] Comparative Example 3:

[0106] This comparative example provides a blue light-excited Ce 3+ Doped yellow phosphors have the general formula Yi 3-x Al5O 12 :xCe 3+ x is 0.05. The specific preparation method is as follows:

[0107] (1) Y2O3, Al2O3 and CeO2 are selected as starting materials, Y2O3:Al2O3:CeO2=0.5681:0.4289:0.0028, corresponding to x=0.01. Weigh the three materials respectively and control the total mass of the raw material mixture to be 1g of mixed raw materials.

[0108] (2) Place the obtained raw material mixture in an agate mortar and grind for 20-50 minutes. After the material is mixed evenly, load the mixture into an alumina crucible. Then place the alumina crucible containing the raw material in the air and calcine at 1600℃ for 12 hours. After cooling to room temperature, the target product is obtained.

[0109] This invention uses X-ray diffraction (Ultima, IV-185) to test the crystal structure of the fluorescent material prepared in Example 1. Cu-Kα was used as the target material, and the scanning angle 2θ ranged from 10 to 80°. The obtained XRD diffraction pattern is shown below. Figure 1 As shown. From Figure 1 It can be seen that the fluorescent material is consistent with the standard card, indicating that Eu 3+ Ion doping did not significantly affect the crystal structure, and the resulting fluorescent material was similar to La2MgNbO. 6.5 It is a homogeneous, pure-phase material. Fluorescence emission spectral data of the fluorescent material indicate that its emission is in the red light region, making it a suitable red-emitting fluorescent material for white LEDs.

[0110] Furthermore, the present invention uses a fluorescence spectrometer (HITACHI, F-7000) to test the spectral properties of the aforementioned phosphor. For example... Figure 2 As shown in the photoexcitation / emission spectrum, the blue-light-excited red phosphor prepared in Example 1 of this invention exhibits a narrow band characteristic, with a stable emission peak position and a peak value near 616 nm. The high spectral peak indicates that it can be effectively excited by the blue light chip and is well-matched with it. Under excitation by a 465 nm blue light source, the phosphor emits bright positive red light, with an emission spectral peak at 616 nm. In comparison, the Y-ray diffraction of Comparative Example 1... 2-x O3:xEu 3+ Phosphor and Ca in Comparative Example 2 1-x MoO4:xEu 3+ The spectral intensity of the phosphor is significantly lower than that of Example 1, indicating that the red phosphor of the present invention has better luminescence effect, and its durability and stability are also significantly higher than those of the existing Eu phosphor. 3+ Doped with red phosphor.

[0111] In addition, such as Figure 3 As shown in the photoexcitation / emission spectra, the red phosphors in Examples 2-10 all have similar photoluminescence properties to those in Example 1, and can emit bright positive red light under blue light source excitation at 465nm.

[0112] Application Example 1:

[0113] This application example demonstrates the use of blue light-excited red phosphor in the fabrication of LED devices.

[0114] Specifically, in this application example, the red phosphor prepared in Example 1 and the yellow phosphor in Comparative Example 3 are respectively packaged with a 465nm blue LED chip to prepare a white LED device. The luminous performance of the packaged white LED device is tested using an automatic temperature-controlled LED photoelectric analyzer (HAAS-2000), and the results are as follows. Figure 4 Electroluminescence spectra shown in a and 4b.

[0115] from Figure 4 As can be seen from Figure a, the high-performance white LED encapsulated with the red phosphor prepared in this invention has a color rendering index (Ra) as high as 88.3 and a correlated color temperature (CCT) as low as 4462K. This indicates that the white LED of this invention can better reproduce the true colors of objects, making it suitable for scenarios requiring high color fidelity and for warm, comfortable lighting environments. In contrast, the white LED encapsulated with yellow phosphor has a color rendering index of only 68.3, but a correlated color temperature as high as 4940K.

[0116] The results above show that the Eu prepared in this invention... 3+ La2MgNbO doped 6.5 Red phosphors have excellent application potential in white LED devices based on blue LED chips, which can meet the needs of the commercial market and further adapt to applications such as white LEDs, solar-like LEDs, and full-spectrum LEDs.

[0117] Application Example 2:

[0118] This application example provides a red fluorescent ceramic prepared from the red fluorescent material of Example 9, and the specific preparation method is as follows:

[0119] (1) Pulping ball milling:

[0120] Take 2.5g of monomer (N,N-dimethylacrylamide), 0.13g of crosslinking agent (N,N'-methylenebisacrylamide), and 3.25g of dispersant (ammonium polyacrylate, 40wt%) and add them to 15g of deionized water. Stir until homogeneous to obtain a premix. Add 60g of red fluorescent ceramic precursor powder (i.e., La) to the premix. 1.91 MgNbO 6.5 0.09Eu 3+ The mixture was stirred to obtain a slurry. The slurry and grinding balls were added to a ball mill jar (the mass ratio of grinding balls to slurry was 1:1) for the first ball milling, which lasted for 6 hours. Then, 20g of red fluorescent ceramic precursor powder (La) was added. 1.91 MgNbO 6.5 0.09Eu 3+ The mixture was then ball-milled a second time for 6 hours; then 20g of red fluorescent ceramic precursor powder (La) was added. 1.91 MgNbO6.5 0.09Eu 3+ The mixture is then subjected to a third ball milling process for 6 hours to obtain the slurry for injection molding.

[0121] (2) Gel injection molding:

[0122] Add 1.5g of catalyst (N,N,N,N,-tetramethylethylenediamine, 5wt%) to the slurry for injection molding and ball mill for the fourth time for 0.5h. Then add 0.5g of initiator (ammonium persulfate, 1.5wt%), stir rapidly for 0.5min, and immediately use the prepared mold for injection molding to obtain the green body.

[0123] (3) Drying and dehydration:

[0124] After the blank has solidified and set, it is placed in an oven at 80°C and dried for 48 hours. Once 90% of the moisture has been removed, the drying process is complete.

[0125] (4) Sintering treatment:

[0126] After drying, the blank is transferred to a muffle furnace for sintering at 1600℃ for 24 hours. After sintering, it is cooled to room temperature at a rate of 5℃ / min to obtain red fluorescent ceramic.

[0127] The fluorescent ceramics prepared from the blue light-excited red fluorescent material obtained in this invention yield the following results: Figure 5 The photoexcitation-emission spectrum shows that under 465nm blue light excitation, the fluorescent ceramic emits bright positive red light, with an emission peak at 616nm. The luminescence intensity is 1.575 times that before sintering, indicating a further improvement in luminescence intensity. Furthermore, compared to traditional fluorescent conversion materials, it possesses better thermal conductivity, reducing the temperature rise caused by high-energy excitation and slowing down the performance degradation of the phosphor, thus significantly extending the device's lifespan. It has the potential to be used as a fluorescent conversion material under high-power-density excitation light source conditions.

[0128] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A blue-light-excited red-light fluorescent material, characterized in that, The chemical formula of the red fluorescent material is La. 2- x MgNbO 6.5 : x Eu 3+ , where 0.01≤ x ≤0.1; The excitation spectrum of the red fluorescent material is in the range of 200-550 nm. The emission spectrum of the red fluorescent material is in the range of 550-720 nm.

2. The blue-light-excited red-light fluorescent material according to claim 1, characterized in that, The x The values ​​are 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, or 0.

1.

3. The blue-light-excited red-light fluorescent material according to claim 1, characterized in that, The central excitation wavelength of the red fluorescent material is 465 nm. The central emission wavelength of the red fluorescent material is 616 nm.

4. The blue-light-excited red-light fluorescent material according to claim 1, characterized in that, The red fluorescent material is prepared by the following steps: Lanthanum oxide, magnesium oxide, niobium oxide, and europium oxide raw materials are weighed according to stoichiometric ratio, and ground and mixed evenly. The evenly mixed powder is sintered at high temperature in a muffle furnace under an air atmosphere. After cooling to room temperature, the red fluorescent material is obtained.

5. A blue-light-excited red-light fluorescent material according to claim 4, characterized in that, The high-temperature sintering temperature is 1200-1600 ℃, and the high-temperature sintering time is 6-10 h; The cooling rate is 1-5 °C / min.

6. An LED device, characterized in that, It comprises a red fluorescent material excited by blue light as described in any one of claims 1-5; the LED device is a white LED device.

7. An LED device according to claim 6, characterized in that, The white LED device is made by encapsulating a red fluorescent material and a 465 nm blue LED chip. The color rendering index of the white LED device is not less than 80; The correlated color temperature of the white LED device is not higher than 4500 K.

8. A fluorescent ceramic, characterized in that, The red fluorescent material excited by blue light as described in any one of claims 1-5; The fluorescent ceramic is prepared from the following raw material components in parts by weight: 90-110 parts of red fluorescent material, 2-3 parts of monomer, 0.1-0.15 parts of crosslinking agent, 1.3-3.75 parts of dispersant, 12-25 parts of solvent, 0.8-2 parts of catalyst, and 0.2-1 parts of initiator.

9. A fluorescent ceramic according to claim 8, characterized in that, The monomer is N,N-dimethylacrylamide, the crosslinking agent is N,N'-methylenebisacrylamide, the dispersant is ammonium polyacrylate, the catalyst is N,N,N,N'-tetramethylethylenediamine, and the initiator is ammonium persulfate.

10. A fluorescent ceramic according to claim 8, characterized in that, The fluorescent ceramic was prepared using the following method: S1: The monomer, dispersant and crosslinking agent are added to the solvent and mixed to obtain a premix; then red fluorescent material is added to the premix in batches and ball milled to obtain a precursor slurry; S2: Add a catalyst to the precursor slurry and ball mill it to obtain a molding slurry; add an initiator to the molding slurry and then perform molding and gelation to obtain a preform; S3: Dry the green body, then sinter it at 1200-1700 ℃ for 12-24 h, and cool it to room temperature after sintering to obtain the fluorescent ceramic.

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