Self-activated dark red light fluorescent material as well as preparation method and application thereof

Abstract

The invention relates to a self-activated dark red light fluorescent material and a preparation method and application thereof, the dark red light fluorescent material is a La2O3-MgO-A2O5 system, and A is selected from one or more of Nb, Ta or Sb. The La2O3-MgO-A2O5 system comprises the following components in percentage by mass of oxides: more than or equal to 55.17% and less than or equal to 65.62% of La2O3, more than or equal to 6.70% and less than or equal to 8.28% of MgO, and more than or equal to 26.50% and less than or equal to 37.79% of A2O5. Compared with the prior art, the fluorescent material disclosed by the invention can be excited by near ultraviolet, purple light and blue light, can effectively absorb purple light with the wavelength of 343 nm and emit strong dark red light with the central wavelength of 708 nm, and is a good candidate material which can be widely applied.

Description

Technical Field

[0001] This invention relates to the field of fluorescent material preparation technology, and in particular to a self-activated deep red fluorescent material, its preparation method, and its application. Background Technology

[0002] Food engineering is one of the most important disciplines concerning human survival. With the emergence of modern and international cities, the growth of urban populations, and climate change, food production has become a problem. Furthermore, in some parts of the world, such as near Poland, months without sunshine make food production difficult. Therefore, new strategies for creating new farms with faster food production (such as indoor farms) are of great significance. Red and far-red light play a crucial role in plant photosynthesis and morphogenesis. Deep red emission in the 650–750 nm range primarily affects phytochrome P450 (P2P) emission. R and P FR This technology plays a crucial role in regulating plant growth rhythms and morphogenesis. With the rapid development of plant lighting technology, phosphor-based light-emitting diodes (pc-LEDs) have become widely used in plant growth lighting due to their energy-saving, environmentally friendly, low-heat-radiation, controllable spectrum, and long lifespan characteristics. Especially in terms of spectral band control, by combining suitable red phosphor materials with commercially available blue LED chips, the needs of plants for red, far-red, and blue light can be simultaneously met.

[0003] Self-activated inorganic luminescent materials can achieve photoluminescence without the need for doping with activating ions, and their luminescence behavior is usually related to their own properties. Since they do not require doping with any rare earth ions or transition metal ions, they offer advantages in terms of simplicity and low cost in terms of preparation process. Patent CN118206989A discloses a self-activated deep-red and near-infrared phosphor, its preparation method, and its application. Its chemical formula is LiZnNbO4:xA, where 0≤x≤0.1, and A is one of the elements Na, Pr, Tm, Sm, Dy, Tb, Er, and Ho. The deep-red and near-infrared phosphor is prepared by weighing raw materials according to the stoichiometric ratio of the chemical formula LiZnNbO4:xA, grinding and mixing them, and then heating and holding the mixture in a corundum crucible to obtain the product. The product is then crushed, ground, graded, and sieved. This invention provides a deep-red and near-infrared phosphor with a simple and easy-to-operate preparation method, low cost, high environmental friendliness, stable chemical properties, good luminescence efficiency, and high excitation efficiency under ultraviolet light. However, the excitation wavelength range of this phosphor is 230–375 nm, meaning it can only be excited under ultraviolet light and cannot respond to a wider range of light sources such as violet and blue light. This limits its compatibility with different types of LED chips in practical applications and reduces its adaptability in scenarios such as plant lighting. Furthermore, this invention requires doping with rare earth ions to control the luminescence intensity; rare earth elements are expensive, increasing the cost. Summary of the Invention

[0004] The purpose of this invention is to provide a self-activated deep red fluorescent material, its preparation method and application, which can be excited by light in the range of 250-600nm and can be adapted to commercial chips with ultraviolet, violet and blue light.

[0005] The objective of this invention can be achieved through the following technical solution: a self-activated deep red fluorescent material, wherein the deep red fluorescent material is a La2O3-MgO-A2O5 system;

[0006] Where A is selected from one or more of Nb, Ta, or Sb;

[0007] The components in the La2O3-MgO-A2O5 system, by mass percentage of oxides, are: 55.17%≤La2O3≤65.62%, 6.70%≤MgO≤8.28%, and 26.50%≤A2O5≤37.79%.

[0008] Preferably, in the La2O3-MgO-A2O5 system, the molar ratio of La:Mg:A is (1.98-2.02):(0.98-1.02):1.

[0009] More preferably, in the La2O3-MgO-A2O5 system, the molar ratio of component La:Mg:A is 1.98:1.02:1, or the molar ratio of component La:Mg:A is 1.99:1.01:1, or the molar ratio of component La:Mg:A is 2:1:1, or the molar ratio of component La:Mg:A is 2.01:0.99:1, or the molar ratio of component La:Mg:A is 2.02:0.98:1.

[0010] Preferably, the deep red fluorescent material exhibits broadband deep red light emission of 650–850 nm centered at 708 nm when excited by near-ultraviolet light.

[0011] More preferably, the deep red fluorescent material exhibits broadband deep red light emission of 650–750 nm centered at 708 nm when excited by near-ultraviolet light.

[0012] Preferably, the excitation spectrum of the deep red fluorescent material is in the range of 250-600 nm, with the optimal excitation position being ultraviolet light at 343 nm.

[0013] Preferably, the emission center of the emission spectrum of the deep red fluorescent material is 708 nm.

[0014] A method for preparing the above-mentioned self-activated deep red fluorescent material involves first grinding lanthanum source compound, magnesium source compound, and niobium / tantalum / antimony source compound (i.e., niobium source compound, tantalum source compound, or antimony source compound) thoroughly in a mortar, mixing them evenly, and then sintering them in an air atmosphere to obtain the self-activated deep red fluorescent material.

[0015] Preferably, the preparation method of the self-activated deep red fluorescent material specifically includes the following steps:

[0016] S1. Weigh out the lanthanum source compound, magnesium source compound, and niobium / tantalum / antimony source compound according to the proportions and grind and mix them in a mortar to obtain a mixture;

[0017] S2. Sinter the mixture in an air atmosphere to obtain the precursor;

[0018] S3. The precursor is ground and mixed twice, and sintered in an air atmosphere to obtain a self-activated deep red fluorescent material.

[0019] More preferably, the grinding time in step S1 is 5-120 min.

[0020] More preferably, the grinding time in step S1 is 20-50 min.

[0021] More preferably, the grinding time in step S3 is 5-120 min.

[0022] More preferably, the grinding time in step S3 is 20-50 min.

[0023] More preferably, the sintering temperature in step S2 is 200-800℃, and the time is 5-24h.

[0024] More preferably, the sintering temperature in step S2 is 300-650℃ and the time is 5-12h.

[0025] More preferably, the sintering temperature in step S3 is 1000-1700℃, and the time is 1-24h.

[0026] More preferably, the sintering temperature in step S3 is 1200-1550℃, and the time is 4-18h.

[0027] More preferably, during sintering in step S2, the system maintains a pressure of 0.8 to 1.2 standard atmospheres.

[0028] More preferably, during sintering in step S2, the system maintains 1 standard atmosphere.

[0029] More preferably, during sintering in step S3, the system maintains a pressure of 0.8 to 1.2 standard atmospheres.

[0030] More preferably, during sintering in step S3, the system maintains 1 standard atmosphere.

[0031] Preferably, the lanthanum source compound is selected from one or more of elemental lanthanum, oxides, chlorides, sulfides, carbonates, sulfates, phosphates, and nitrates.

[0032] More preferably, the lanthanum source compound is selected from oxides of lanthanum.

[0033] Preferably, the magnesium source compound is selected from one or more of elemental magnesium, oxides, chlorides, sulfides, carbonates, sulfates, phosphates, and nitrates.

[0034] More preferably, the magnesium source compound is selected from magnesium oxides.

[0035] Preferably, the niobium source compound is selected from one or more of elemental niobium, oxides, chlorides, sulfides, carbonates, sulfates, phosphates, and nitrates.

[0036] More preferably, the niobium source compound is selected from niobium oxides.

[0037] Preferably, the tantalum source compound is selected from one or more of elemental tantalum, oxides, chlorides, sulfides, carbonates, sulfates, phosphates, and nitrates.

[0038] More preferably, the tantalum source compound is selected from tantalum oxides.

[0039] Preferably, the antimony source compound is selected from one or more of antimony element, oxide, chloride, sulfide, carbonate, sulfate, phosphate, and nitrate.

[0040] More preferably, the antimony source compound is selected from antimony oxides.

[0041] An application of the above-mentioned self-activated deep red fluorescent material is to use the deep red fluorescent material in the preparation of LED light sources.

[0042] This invention provides an application of a self-activated deep red fluorescent material in light-emitting diode (LED) light sources.

[0043] Preferably, the deep red fluorescent material is used for plant lighting.

[0044] An LED light source comprising the aforementioned self-activated deep red fluorescent material.

[0045] This invention provides a novel inorganic self-activated luminescent material, La2O3-MgO-A2O5, which exhibits broadband deep red light emission centered at 708 nm in the 650–850 nm range under near-ultraviolet light excitation without requiring any activator ions for doping. Furthermore, to modulate the spectral performance, defects were artificially introduced to enhance luminescence by adjusting the cation ratio. Notably, the deep red-near-infrared emission of the synthesized series of phosphors coincides with the absorption range of plant phytochromes (Pr and Pfr), indicating that the prepared phosphors show great potential for plant growth illumination.

[0046] Compared with the prior art, the present invention has the following beneficial effects:

[0047] 1. The phosphor of this invention can be excited by near-ultraviolet, violet, and blue light, and can effectively absorb violet light with a wavelength of 343nm and emit strong deep red light with a center wavelength of 708nm;

[0048] 2. The phosphor of this invention can be excited by light in the range of 250-600nm, and can be adapted to commercial chips for ultraviolet, violet and blue light, thus improving its adaptability in scenarios such as plant lighting;

[0049] 3. This invention eliminates the need for doping with rare earth ions to regulate luminescence intensity, thus reducing costs;

[0050] 4. The phosphor of this invention is a self-activated deep red fluorescent material with the advantage of stable physicochemical properties. At the same time, the phosphor can be prepared by solid-phase reaction method, which has the characteristics of simple preparation process, low cost and easy industrial production, and is a good candidate material that can be widely used.

[0051] 5. This invention provides a self-activated deep red phosphor that is simple to prepare, easy to operate, low-cost, environmentally friendly, chemically stable, and has good luminescence efficiency, and can be efficiently excited by ultraviolet light;

[0052] 6. The material obtained by this invention can be used to prepare a self-activated deep red light source. The phosphor can achieve deep red light emission without doping with any activating luminescent ions, which expands the types and research of phosphor-converted deep red LEDs. Moreover, it avoids the disadvantages of commonly used activators such as the high price and narrow spectral range of rare earth ions, and becomes a new way to efficiently generate deep red light.

[0053] 7. The optimal excitation of the self-activated deep red phosphor proposed in this invention is located in the ultraviolet region of 343 nm, emitting deep red light with a main peak at 708 nm and color coordinates of (0.710, 0.269). Attached Figure Description

[0054] Figure 1The images show the photoexcitation-emission spectra of the self-activated deep red fluorescent materials in Examples 1-5 of this invention.

[0055] Figure 2 The XRD spectra of the self-activated deep red fluorescent materials in Examples 1 to 5 of this invention are shown.

[0056] Figure 3 The LED device and photosensitive pigment P fabricated using the self-activated deep red fluorescent material and 410nm commercial chip in Example 1 of this invention FR Absorption range comparison chart;

[0057] Figure 4 This is the photoexcitation-emission spectrum of the self-activated deep red fluorescent material in Example 1 of the present invention. Detailed Implementation

[0058] 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.

[0059] Unless otherwise specified, the equipment used in the following embodiments is conventional equipment in the art; unless otherwise specified, the reagents used are commercially available products or prepared by conventional methods in the art. In the following embodiments, unless otherwise described in detail, conventional experimental methods in the art can be used.

[0060] Example 1

[0061] A self-activated deep red fluorescent material and its preparation method are disclosed, which are applied in light-emitting diode (LED) light sources. The specific steps are as follows:

[0062] S1. Lanthanum oxide (La2O3), magnesium oxide (MgO), and tantalum pentoxide (Ta2O5) are selected as starting materials, with La:Mg:Ta = 2:1:1 (molar ratio). The three raw material powders are weighed according to the stoichiometric ratio, and the total mass of the raw material powders is controlled to be 10g. The raw material powders are placed in an agate mortar and ground thoroughly for 20min to mix evenly to obtain a mixture.

[0063] S2. Place the mixture in an alumina crucible, place the alumina crucible containing the mixture in a muffle furnace, calcine at 300°C for 5 hours in an air atmosphere, maintain a pressure of 1 atm, and allow it to cool naturally to room temperature to obtain the precursor.

[0064] S3. Place the precursor in an agate mortar and grind it thoroughly for 20 minutes to mix it evenly. Place the precursor in an alumina crucible and place it in a muffle furnace. Sinter it at 1200°C for 4 hours in an air atmosphere with a pressure of 1 atm. Allow it to cool naturally to room temperature to obtain a powdered self-activated deep red fluorescent material.

[0065] The above materials were subjected to the following tests or experiments, and the results were then analyzed.

[0066] Experimental example:

[0067] The spectral properties of the above materials were tested using a fluorescence spectrometer (HITACHI F-7500).

[0068] like Figure 1 As shown, the results indicate that the phosphor in Example 1 can be excited by near-ultraviolet, violet, or blue light, with the peak of the excitation spectrum located in the ultraviolet region; the center wavelength of the emission spectrum is 708 nm.

[0069] like Figure 4 As shown, under the excitation of a 343nm ultraviolet light source, the phosphor in Example 1 emits bright red light, with an emission spectrum covering 650-850nm and a peak at 708nm.

[0070] The electroluminescence properties of the above materials were tested using a high-precision fast spectroradiometer (HAAS-2000, EVERFINE).

[0071] like Figure 3 As shown, the prepared self-activated deep red fluorescent material was combined with a commercial 410nm chip, encapsulated into an LED device, and its spectrum was tested. It was found that it interacts with the photosensitive pigment P. FR The high degree of overlap in their absorption ranges indicates that they have great potential for application in plant lighting.

[0072] like Figure 2 As shown, the XRD diffraction peaks of Example 1 are basically consistent with those of the standard card, indicating that a pure-phase fluorescent material has been prepared.

[0073] Example 2

[0074] A self-activated deep red fluorescent material and its preparation method are basically the same as in Example 1, except that in step S1, La:Mg:Ta = 1.99:1.01:1 (molar ratio), in step S2, the material is calcined at 350°C for 6 hours in air, and in step S3, it is sintered at 1250°C for 6 hours in air. The specific steps are as follows:

[0075] S1. Lanthanum oxide, magnesium oxide, and tantalum pentoxide were selected as starting materials, with La:Mg:Ta = 1.99:1.01:1. The three raw material powders were weighed according to the measurement ratio, and the total mass of the raw material powders was controlled to be 10g. The raw material powders were placed in an agate mortar and ground thoroughly for 20min to mix evenly to obtain a mixture.

[0076] S2. Place the mixture in an alumina crucible, place the alumina crucible containing the mixture in a muffle furnace, calcine at 350°C for 6 hours in an air atmosphere, and allow it to cool naturally to room temperature to obtain the precursor.

[0077] S3. Place the precursor back into the agate mortar and grind it thoroughly for 20 minutes to mix evenly. Place the precursor into an alumina crucible, place it in a muffle furnace, and sinter it at 1250°C for 6 hours in an air atmosphere with a pressure of 1 atm. Allow it to cool naturally to room temperature to obtain a powdered self-activated deep red fluorescent material.

[0078] like Figure 1 As shown, the results indicate that the phosphor in Example 2 can be excited by near-ultraviolet, violet, or blue light, with the peak of the excitation spectrum located in the violet region; the center wavelength of the emission spectrum is 708 nm.

[0079] When excited by a 343nm ultraviolet light source, the phosphor in Example 2 emits bright red light, with an emission spectrum covering 650-850nm and a peak at 708nm.

[0080] like Figure 2 As shown, the XRD diffraction peaks of Example 2 are basically consistent with those of the standard card, indicating that a pure-phase fluorescent material has been prepared.

[0081] Example 3

[0082] A self-activated deep red fluorescent material and its preparation method are basically the same as in Example 1, except that in step S1, La:Mg:Ta = 1.98:1.02:1 (molar ratio), in step S2, the material is calcined at 400°C for 7 hours in air, and in step S3, it is sintered at 1300°C for 8 hours in air. The specific steps are as follows:

[0083] S1. Lanthanum oxide, magnesium oxide, and tantalum pentoxide were selected as starting materials, with a molar ratio of La:Mg:Ta = 1.98:1.02:1. The three raw material powders were weighed according to the stoichiometric ratio, and the total mass of the raw material powders was controlled to be 10g. The raw material powders were placed in an agate mortar and ground thoroughly for 20min to mix evenly, thus obtaining a mixture.

[0084] S2. Place the mixture in an alumina crucible, place the alumina crucible containing the mixture in a muffle furnace, and calcine at 400°C for 7 hours in an air atmosphere. Allow it to cool naturally to room temperature to obtain the precursor.

[0085] S3. Place the precursor in an agate mortar and grind it thoroughly for 20 minutes to mix it evenly. Place the precursor in an alumina crucible and place it in a muffle furnace. Sinter it at 1300℃ for 8 hours in an air atmosphere with a pressure of 1 atm. Allow it to cool naturally to room temperature to obtain a powdered self-activated deep red fluorescent material.

[0086] like Figure 1 As shown, the results indicate that the phosphor in Example 3 can be excited by near-ultraviolet, violet, or blue light, with the peak of the excitation spectrum located in the violet region; the center wavelength of the emission spectrum is 708 nm.

[0087] When excited by a 410nm violet light source, the phosphor in Example 3 emits bright red light, with an emission spectrum covering 650-850nm and a peak at 708nm.

[0088] like Figure 2 As shown, the XRD diffraction peaks of Example 3 are basically consistent with those of the standard card, indicating that a pure-phase fluorescent material was prepared.

[0089] Example 4

[0090] A self-activated deep red fluorescent material and its preparation method are basically the same as in Example 1, except that in step S1, La:Mg:Ta = 2.01:0.99:1 (molar ratio), in step S2, it is calcined at 450°C for 8 hours in air atmosphere, and in step S3, it is sintered at 1350°C for 10 hours in air atmosphere. The specific steps are as follows:

[0091] S1. Lanthanum oxide, magnesium oxide, and tantalum pentoxide were selected as starting materials, with a molar ratio of La:Mg:Ta = 2.01:0.99:1. The three raw material powders were weighed according to the stoichiometric ratio, and the total mass of the raw material powders was controlled to be 10g. The raw material powders were placed in an agate mortar and ground thoroughly for 20min to mix evenly, thus obtaining a mixture.

[0092] S2. Place the mixture in an alumina crucible, place the alumina crucible containing the mixture in a muffle furnace, calcine at 450°C for 8 hours in an air atmosphere, and allow it to cool naturally to room temperature to obtain the precursor.

[0093] S3. Place the precursor in an agate mortar and grind it thoroughly for 20 minutes to mix evenly. Place the precursor in an alumina crucible and place it in a muffle furnace. Sinter at 1350°C for 10 hours in an air atmosphere with a pressure of 1 atm. Allow it to cool naturally to room temperature to obtain a powdered self-activated deep red fluorescent material.

[0094] like Figure 1 As shown, the results indicate that the phosphor in Example 4 can be excited by near-ultraviolet, violet, or blue light, with the peak of the excitation spectrum located in the violet region; the center wavelength of the emission spectrum is 708 nm.

[0095] When excited by a 410nm violet light source, the phosphor in Example 4 emits bright red light, with an emission spectrum covering 650-850nm and a peak at 708nm.

[0096] like Figure 2 As shown, the XRD diffraction peaks of Example 4 are basically consistent with those of the standard card, indicating that a pure-phase fluorescent material was prepared.

[0097] Example 5

[0098] A self-activated deep red fluorescent material and its preparation method are basically the same as in Example 1, except that in step S1, La:Mg:Ta = 2.02:0.98:1 (molar ratio), in step S2, it is calcined at 500°C for 9 hours in air, and in step S3, it is sintered at 1350°C for 10 hours in air. The specific steps are as follows:

[0099] S1. Lanthanum oxide, magnesium oxide, and tantalum pentoxide were selected as starting materials, with a molar ratio of La:Mg:Ta = 2.02:0.98:1. The three raw material powders were weighed according to the stoichiometric ratio, and the total mass of the raw material powders was controlled to be 10g. The raw material powders were placed in an agate mortar and ground thoroughly for 20min to mix evenly, thus obtaining a mixture.

[0100] S2. Place the mixture in an alumina crucible, place the alumina crucible containing the mixture in a muffle furnace, calcine at 500°C for 9 hours in an air atmosphere, and allow it to cool naturally to room temperature to obtain the precursor.

[0101] S3. Place the precursor in an agate mortar and grind it thoroughly for 20 minutes to mix evenly. Place the precursor in an alumina crucible and place it in a muffle furnace. Sinter at 1350°C for 10 hours in an air atmosphere with a pressure of 1 atm. Allow it to cool naturally to room temperature to obtain a powdered self-activated deep red fluorescent material.

[0102] like Figure 1 As shown, the results indicate that the phosphor in Example 5 can be excited by near-ultraviolet, violet, or blue light, with the peak of the excitation spectrum located in the violet region; the center wavelength of the emission spectrum is 708 nm.

[0103] When excited by a 410nm violet light source, the phosphor in Example 5 emits bright red light, with an emission spectrum covering 650-850nm and a peak at 708nm.

[0104] like Figure 2 As shown, the XRD diffraction peaks of Example 5 are basically consistent with those of the standard card, indicating that a pure-phase fluorescent material was prepared.

[0105] Example 6

[0106] A self-activated deep red fluorescent material and its preparation method are basically the same as in Example 1, except that in step S1, La:Mg:Nb = 2:1:1 (molar ratio), in step S2, it is calcined at 550°C for 10 hours in air, and in step S3, it is sintered at 1400°C for 12 hours in air. The specific steps are as follows:

[0107] S1. Lanthanum oxide, magnesium oxide, and niobium pentoxide were selected as starting materials, with a molar ratio of La:Mg:Nb = 2:1:1. The three raw material powders were weighed according to the stoichiometric ratio, and the total mass of the raw material powders was controlled to be 10g. The raw material powders were placed in an agate mortar and ground thoroughly for 20min to mix evenly to obtain a mixture.

[0108] S2. Place the mixture in an alumina crucible, place the alumina crucible containing the mixture in a muffle furnace, calcine at 550°C for 10 hours in an air atmosphere, and allow it to cool naturally to room temperature to obtain the precursor.

[0109] S3. Place the precursor in an agate mortar and grind it thoroughly for 20 minutes to mix it evenly. Place the precursor in an alumina crucible and place it in a muffle furnace. Sinter it at 1400℃ for 12 hours in an air atmosphere with a pressure of 1 atm. Allow it to cool naturally to room temperature to obtain a powdered self-activated deep red fluorescent material.

[0110] The results showed that the luminescence properties of the phosphor in Example 6 were similar to those in Example 1.

[0111] Example 7

[0112] A self-activated deep red fluorescent material and its preparation method are basically the same as in Example 1, except that in step S1, La:Mg:Sb = 2:1:1 (molar ratio), in step S2, it is calcined at 600°C for 11 hours in air, and in step S3, it is sintered at 1500°C for 16 hours in air. The specific steps are as follows:

[0113] S1. Lanthanum oxide, magnesium oxide, and antimony pentoxide were selected as starting materials, with a molar ratio of La:Mg:Sb = 2:1:1. The three raw material powders were weighed according to the stoichiometric ratio, and the total mass of the raw material powders was controlled to be 10g. The raw material powders were placed in an agate mortar and ground thoroughly for 20min to mix evenly, thus obtaining a mixture.

[0114] S2. Place the mixture in an alumina crucible, place the alumina crucible containing the mixture in a muffle furnace, calcine at 600°C for 11 hours in an air atmosphere, and allow it to cool naturally to room temperature to obtain the precursor.

[0115] S3. Place the precursor in an agate mortar and grind it thoroughly for 20 minutes to mix evenly. Place the precursor in an alumina crucible and place it in a muffle furnace. Sinter at 1500°C for 16 hours in an air atmosphere with a pressure of 1 atm. Allow it to cool naturally to room temperature to obtain a powdered self-activated deep red fluorescent material.

[0116] The results showed that the luminescence properties of the phosphor in Example 7 were similar to those in Example 1.

[0117] Example 8

[0118] A self-activated deep red fluorescent material and its preparation method are basically the same as in Example 1, except that in step S1, La:Mg:Sb = 2.02:0.98:1 (molar ratio), in step S2, it is calcined at 650°C for 12 hours in air, and in step S3, it is sintered at 1550°C for 18 hours in air. The specific steps are as follows:

[0119] S1. Lanthanum oxide, magnesium oxide, and antimony pentoxide were selected as starting materials, with a molar ratio of La:Mg:Sb = 2.02:0.98:1. The three raw material powders were weighed according to the stoichiometric ratio, and the total mass of the raw material powders was controlled to be 10g. The raw material powders were placed in an agate mortar and ground thoroughly for 20min to mix evenly, thus obtaining a mixture.

[0120] S2. Place the mixture in an alumina crucible, place the alumina crucible containing the mixture in a muffle furnace, calcine at 650°C for 12 hours in an air atmosphere, and allow it to cool naturally to room temperature to obtain the precursor.

[0121] S3. Place the precursor in an agate mortar and grind it thoroughly for 20 minutes to mix it evenly. Place the precursor in an alumina crucible and place it in a muffle furnace. Sinter it at 1550°C for 18 hours in an air atmosphere with a pressure of 1 atm. Allow it to cool naturally to room temperature to obtain a powdered self-activated deep red fluorescent material.

[0122] The results showed that the luminescent properties of the phosphor in Example 8 were similar to those in Example 1.

[0123] Comparative Example 1

[0124] A self-activated deep red fluorescent material and its preparation method are basically the same as those in Example 1, except that in step S1, the raw material is weighed and placed directly into an alumina crucible, and in step S3, the unground precursor is placed directly into a muffle furnace for calcination. The specific steps are as follows:

[0125] S1. Lanthanum oxide, magnesium oxide, and tantalum pentoxide are selected as starting materials, with La:Mg:Ta = 2:1:1. The three raw material powders are weighed according to the metering ratio, and the total mass of the raw material powder is controlled to be 10g.

[0126] S2. Place the raw material weighed in S1 into an alumina crucible, place the alumina crucible containing the raw material into a muffle furnace, calcine at 350°C for 5 hours in an air atmosphere, maintain a pressure of 1 atm, and allow it to cool naturally to room temperature to obtain the precursor.

[0127] S3. Place the precursor in an alumina crucible, place it in a muffle furnace, and sinter at 1200°C for 4 hours in an air atmosphere with a pressure of 1 atm. Allow it to cool naturally to room temperature to obtain a powdered self-activated deep red fluorescent material.

[0128] The results showed that the luminescence properties of the phosphor in Comparative Example 1 were similar to those in Example 1, but the luminescence intensity was significantly reduced.

[0129] 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 self-activated deep red fluorescent material, characterized in that, The deep red fluorescent material is a La2O3-MgO-A2O5 system; Where A is selected from Nb, Ta, and Sb; The components in the La2O3-MgO-A2O5 system, by mass percentage of oxides, are: 55.17%≤La2O3≤65.62%, 6.70%≤MgO≤8.28%, and 26.50%≤A2O5≤37.79%.

2. The self-activated deep red fluorescent material according to claim 1, characterized in that, In the La2O3-MgO-A2O5 system, the molar ratio of La:Mg:A is (1.98-2.02):(0.98-1.02):

1.

3. The self-activated deep red fluorescent material according to claim 1, characterized in that, The deep red fluorescent material exhibits broadband deep red light emission in the 650–850 nm range, centered at 708 nm, when excited by near-ultraviolet light.

4. A method for preparing a self-activated deep red fluorescent material according to any one of claims 1 to 3, characterized in that, Lanthanum source compound, magnesium source compound, and niobium / tantalum / antimony source compound are first thoroughly ground in a mortar and mixed evenly, and then sintered in an air atmosphere to obtain a self-activated deep red fluorescent material.

5. The method for preparing the self-activated deep red fluorescent material according to claim 4, characterized in that, Specifically, the following steps are included: S1. Weigh out the lanthanum source compound, magnesium source compound, and niobium / tantalum / antimony source compound according to the proportions and grind and mix them in a mortar to obtain a mixture; S2. Sinter the mixture in an air atmosphere to obtain the precursor; S3. The precursor is ground and mixed twice, and sintered in an air atmosphere to obtain a self-activated deep red fluorescent material.

6. The method for preparing the self-activated deep red fluorescent material according to claim 5, characterized in that, The grinding time for steps S1 and S3 is 5-120 min.

7. The method for preparing the self-activated deep red fluorescent material according to claim 5, characterized in that, The sintering temperature in step S2 is 200-800℃, and the time is 5-24h.

8. The method for preparing the self-activated deep red fluorescent material according to claim 5, characterized in that, The sintering temperature in step S3 is 1000-1700℃, and the time is 1-24h.

9. The method for preparing the self-activated deep red fluorescent material according to claim 4, characterized in that, The lanthanum source compound is selected from one or more of the following: elemental lanthanum, oxides, chlorides, sulfides, carbonates, sulfates, phosphates, and nitrates. The magnesium source compound is selected from one or more of the following: elemental magnesium, oxides, chlorides, sulfides, carbonates, sulfates, phosphates, and nitrates. The niobium source compound is selected from one or more of elemental niobium, oxides, chlorides, sulfides, carbonates, sulfates, phosphates, and nitrates; The tantalum source compound is selected from one or more of elemental tantalum, oxides, chlorides, sulfides, carbonates, sulfates, phosphates, and nitrates; The antimony source compound is selected from one or more of the following: elemental antimony, oxides, chlorides, sulfides, carbonates, sulfates, phosphates, and nitrates.

10. The application of the self-activated deep red fluorescent material according to any one of claims 1 to 3, characterized in that, The deep red fluorescent material is used to prepare LED light sources.

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