High-efficiency Eu with anti-thermal quenching 3+ Doped borotellurite red phosphor and its preparation method

Abstract

This application discloses a highly efficient Eu anti-thermal quenching 3+ -doped borotellurite red phosphor and its preparation method. The Eu 3+ -doped borotellurite red phosphor has a chemical general formula of Ln 1‑x TeBO5: xEu 3+ , where the doping amount of Eu 3+ is 0 < x ≤ 0.9; Ln is Gd 3+ , La 3+ or Y 3+ ; any one of them; the Eu 3+ -doped borotellurite red phosphor emits red light with a wavelength of 550 - 750 nm under an excitation wavelength of 394 nm. The internal quantum efficiency of this phosphor reaches 95%, the external quantum efficiency reaches 40%, and the absorption efficiency is 34%; at 150 °C and 200 °C, the integrated emission intensity can maintain 99% and 98% of that at room temperature respectively, with almost no loss of emission intensity, approaching near-zero thermal quenching.

Description

Technical Field

[0001] This application relates to the technical field of inorganic phosphor synthesis, in particular to a high-efficiency Eu 3+ doped borotellurite red phosphor and its preparation method. Background Art

[0002] At present, white light-emitting diodes (WLEDs) are widely used in the fields of lighting and display, but there are still problems of low luminous efficiency and poor luminous quality. Traditional WLEDs generate white light by exciting yellow phosphors with blue light, which have the defects of blue light hazard, high color temperature, and low color rendering index, restricting the application of white light-emitting diodes. To solve the above problems, researchers have proposed a scheme of ultraviolet (UV) light excitation of red, green, and blue primary colors to reduce blue light hazard, lower color temperature, and improve color rendering index. However, the existing red phosphors that can be applied to this scheme have low luminous efficiency and cannot meet the needs of high-luminous-efficiency devices. At the same time, the existing red phosphors are easily affected by the thermal quenching effect, and red phosphors with stable emission colors cannot be obtained.

[0003] Therefore, developing a high-efficiency red phosphor that can be excited by near-ultraviolet light is of great significance for further optimizing the performance of WLEDs.

[0004] Rare earth Eu 3+ is a commonly used red light activator ion. Phosphors doped with Eu 3+ ions can generate a series of emission peaks under ultraviolet light excitation. These emission spectra mainly originate from the excited states within the 4f 6 electronic configuration 5 from D0 to low energy levels 7 F J (J = 0, 1, 2, 3, 4, 5, 6) energy level transitions. According to the J-O theory, 5 D0→ 7 F1 and 5 D0→ 7 F2 transition emission intensity ratios strongly depend on the coordination environment provided by the matrix for Eu 3+ ions. When Eu 3+ ions occupy positions with an inversion symmetry center in the matrix, its emission spectrum will be dominated by the 5 D0→ 7 F1 magnetic dipole transition, emitting orange-red light at about 594 nm. When it occupies a position without an inversion symmetry center, it will be dominated by the 5 D0→ 7 F2 electric dipole transition, emitting red light at about 613 nm.

[0005] However, Eu reported in recent years 3+Most of the doped red phosphors are doped at low concentrations, resulting in low luminous efficiency and being prone to thermal quenching at high temperatures, which limits their application in WLEDs. For example, a Eu 3+ -doped tantalate red phosphor disclosed in CN201610921056.X has the chemical formula La 2-2x Eu 2x Ta 12 O 33 , and the stoichiometric fraction x of Eu 3+ doping is 0.001 ≤ x ≤ 0.20. A Eu 3+ -ion-activated red phosphor disclosed in CN201911094434.1 has the chemical general formula LiAl 1-x Eu x VPO7, where x is the molar ratio of Eu 3+ doping substituting for Al 3+ , and 0.001 ≤ x ≤ 0.1. The Eu 3+ doping amounts in the above existing Eu 3+ -doped red phosphors are all relatively low, and no specific luminous efficiency values of this material are given, only emission spectra and excitation wavelengths are provided.

[0006] There are a wide variety of existing phosphor matrix materials, and the elemental composition, structure, and stability of the matrix materials used in phosphors are crucial for achieving stable luminescence of activators. The matrix material can provide lattice sites or vacancies for activator ions, playing a role in fixing activator ions and providing different crystal field environments for activator ions.

[0007] As a new type of material system, borotellurite has excellent thermal stability, chemical stability, and good optical properties, and has broad application prospects in the lighting field. For example, a borotellurite luminescent glass doped with rare earth ion Eu 3+ disclosed in CN202010557847.5, the glass raw materials of this glass are composed of TeO2, H3BO3, CaF2, TiO2, and K2CO3, and their mass percentages are respectively: TeO2 5 - 20%, H3BO3 5 - 50%, CaF2 10 - 30%, TiO2 1 - 15%, K2CO3 22 - 25%, where the rare earth oxide is Eu2O3, and the mass percentage is 0.1 - 3%. The luminous efficiency of this luminescent glass in the light red region is only 90.1%.

[0008] However, the luminescent glass belongs to amorphous materials and is in a non-crystalline phase. The material properties are completely different from those of the crystalline phosphor materials. Even if the luminescent glass is ground, it is impossible to obtain a phosphor with excellent properties, and the structural change after grinding will lead to the weakening or failure of the luminescent effect. The process of manufacturing the luminescent glass involves adding glass powder and extremely high melting temperatures, resulting in high manufacturing costs. In contrast, the preparation of phosphors is relatively simple, with a lower synthesis temperature and lower costs. At the same time, the literature does not propose effective solutions to the problems of internal quantum efficiency and thermal quenching existing in phosphors.

[0009] In summary, aiming at the problems existing in the prior art, combining the characteristics of Eu 3+ ions and the host material GdTeBO5, we synthesized a series of Gd 1-x TeBO5:Eu 3+ (0≤x≤0.9) red phosphors by the high-temperature solid-state method. The optimal Gd 0.55 TeBO5:0.45Eu 3+ sample prepared has extremely high internal quantum efficiency and nearly zero thermal quenching effect.

[0010] The information disclosed in the background art section is only intended to enhance the overall understanding of the present application and should not be regarded as an admission or any form of implication that this information constitutes the prior art already known to those of ordinary skill in the art. Summary of the Invention

[0011] The present application provides an efficient Eu 3+ -doped borotellurite red phosphor with resistance to thermal quenching and its preparation method. The internal quantum efficiency of this phosphor reaches 95%, the external quantum efficiency reaches 40%, and the absorption efficiency is 34%; at 150 °C and 200 °C, the integrated emission intensity can maintain 99% and 98% of that at room temperature respectively, and the emission intensity hardly decreases, approaching nearly zero thermal quenching.

[0012] The present application provides an Eu 3+ -doped borotellurite red phosphor. The chemical general formula of the Eu 3+ -doped borotellurite red phosphor is Ln 1-x TeBO5:x Eu 3+ , where the doping amount of Eu 3+ is 0 < x ≤ 0.9; Ln is any one of Gd 3+ , La 3+ or Y 3+ .

[0013] Preferably, under the excitation wavelength of 394 nm, the Eu 3+ -doped borotellurite red phosphor emits red light with a wavelength of 550 - 750 nm;

[0014] x = 0.45 and Ln is Gd 3+ When the time is, the chromaticity coordinate values are (0.6504, 0.3493).

[0015] Preferably, x = 0.45 and Ln is Gd 3+ When the time is, Eu 3+ For the Eu-doped borotellurite red phosphor, the integrated luminescence intensity at 150 °C is 99% of that at room temperature; the integrated luminescence intensity at 200 °C is 98% of that at room temperature;

[0016] Preferably, x = 0.45 and Ln is Gd 3+ When the time is, Eu 3+ For the Eu-doped borotellurite red phosphor, at an excitation wavelength of 394 nm, the internal quantum efficiency reaches 95%, the external quantum efficiency reaches 40%, and the absorption efficiency is 34%.

[0017] All the obtained phosphors are synthesized by the commonly used high-temperature solid-phase method in the art. This phosphor can not only be excited by near-ultraviolet light to generate red-band light, but also has good internal quantum efficiency, external quantum efficiency and absorption efficiency; at the same time, the change in the integrated luminescence intensity at high temperature relative to the room temperature environment approaches 0, having high quantum efficiency and high luminescence thermal stability, which can effectively solve the problems of low luminescence efficiency and poor thermal stability of existing red phosphors, and the problem of low doping concentration of Eu 3+ doping concentration.

[0018] The borotellurite GdTeBO5 selected in this application is a new material system with excellent thermal stability, chemical stability and good optical properties, and is an excellent candidate as a phosphor matrix material. The GdTeBO5 structure contains highly distorted [Te(IV)O4] polyhedra, [BO3] planar triangles and [GdO8] polyhedra, and these polyhedra are connected by sharing edges and vertices to form a stable network structure. In this structure, the distance between two adjacent [GdO8] polyhedra is relatively large, and Gd 3+ and Eu 3+ have similar ionic radii. Therefore, GdTeBO5 has the potential to be a candidate matrix material for Eu 3+ doped high-efficiency red phosphors.

[0019] On the other hand, this application also provides a method for preparing the Eu 3+ doped borotellurite red phosphor as described above, which at least includes the following steps:

[0020] After grinding the mixture containing the reaction raw materials, pre-burning is carried out in an atmospheric air atmosphere, and then solid-phase reaction is carried out in an atmospheric air atmosphere to obtain the Eu 3+ doped borotellurite red phosphor;

[0021] The ratio of the reaction raw materials satisfies the composition of the phosphor.

[0022] Preferably, the reaction raw materials are Ln source, Te source, B source, and Eu source; the Ln source is Gd source, La source, or Y source.

[0023] Preferably, the Ln source, Te source, B source, and Eu source are mixed in a molar ratio of 1 - x:2:2:x; 0 < x ≤ 0.9.

[0024] Preferably, the Gd source at least includes Gd2O3; the Te source at least includes TeO2; the B source at least includes H3BO3; the Eu source at least includes Eu2O3; the La source at least includes La2O3; the Y source at least includes Y2O3.

[0025] Preferably, the pre - calcination operation is as follows: heat the reaction materials from room temperature to 250 - 350 °C at a heating rate of 1 - 3 °C / min, keep them at this temperature for 4 - 6 h, and then cool them to room temperature with the furnace. After that, grind them again for 20 - 40 min.

[0026] Preferably, the solid - state reaction operation is as follows: heat the materials obtained from pre - calcination from room temperature to 720 - 760 °C at a heating rate of 1 - 3 °C / min, keep them at this temperature for 45 - 55 h, and then cool them to room temperature at a cooling rate of 1 - 3 °C / min.

[0027] According to these reaction conditions, the above - mentioned phosphor can be prepared.

[0028] Specifically, the preparation method of the above - mentioned phosphor is as follows:

[0029] (1) Weighing: Accurately weigh Gd2O3, TeO2, H3BO3, and Eu2O3 according to the stoichiometric ratio.

[0030] (2) Grinding: Mix all the raw materials and grind them thoroughly in an agate mortar. After grinding, put the reactants into a corundum crucible.

[0031] (3) Pre - calcination stage: Put the corundum crucible containing the reactants into a muffle furnace, set the heating program: heat from room temperature to 250 - 350 °C at a heating rate of 1 - 3 °C / min, keep them at this temperature for 4 - 6 h, and finally, cool them to room temperature with the furnace. Take out the pre - calcined product and grind it again for 20 - 40 min.

[0032] (4) Solid - state reaction stage: Heat the sample after re - grinding from room temperature to 720 - 760 °C at a heating rate of 1 - 3 °C / min, keep it at this temperature for 45 - 55 h, and then cool it to room temperature at a cooling rate of 1 - 3 °C / min. Finally, take out the sample, grind it to obtain the final sample for subsequent characterization tests.

[0033] The beneficial effects that this application can produce include:

[0034] 1) The high-efficiency Eu-doped borotellurite red phosphor with anti-thermal quenching provided by this application. In this phosphor, the doping amount of Eu can reach up to 0.9, which is much higher than that of Eu in the existing matrix. The obtained material has relatively high internal quantum efficiency and external quantum efficiency. The integrated emission intensity at 150 °C and 200 °C can maintain 99% and 98% of the integrated emission intensity at room temperature respectively, showing the performance of nearly zero thermal quenching, effectively solving the problems existing in the existing red phosphors. 3+ 2) The high-efficiency Eu-doped borotellurite red phosphor with anti-thermal quenching provided by this application. The optimal Gd 3 + TeBO5:0.45Eu 3+ sample has an ultra-high internal quantum efficiency of 95% and an external quantum efficiency of up to 40%. And for the Gd

[0035] TeBO5:0.45Eu 3+ phosphor, the integrated emission intensity at 150 °C and 200 °C can maintain 99% and 98% of the integrated emission intensity at room temperature respectively, approaching zero thermal quenching. These beneficial effects indicate that the Gd 0.55 TeBO5:0.45Eu 3+ phosphor provided by this application has great potential when applied as a red component to WLED devices. 0.55 TeBO5:0.45Eu 3+ phosphor, the integrated emission intensity at 150 °C and 200 °C can maintain 99% and 98% of the integrated emission intensity at room temperature respectively, approaching zero thermal quenching. These beneficial effects indicate that the Gd 0.55 TeBO5:0.45Eu 3+ phosphor provided by this application has great potential when applied as a red component to WLED devices.

[0036] 3) The preparation method of the high-efficiency Eu-doped phosphor with anti-thermal quenching provided by this application. The raw materials used for preparing this material are inexpensive, the required reaction equipment is simple, energy-saving and environmentally friendly, and it is suitable for large-scale industrial production. 3+ 3) The preparation method of the high-efficiency Eu-doped phosphor with anti-thermal quenching provided by this application. The raw materials used for preparing this material are inexpensive, the required reaction equipment is simple, energy-saving and environmentally friendly, and it is suitable for large-scale industrial production. Description of the Drawings

[0037] Figure 1 XRD patterns of Gd 1-x TeBO5:Eu 3+ (0 ≤ x ≤ 0.9) obtained in Examples 1, 2, 3, 4, 5, 6, 7, 8, 9 of this application;

[0038] Figure 2 Excitation and emission spectra of Gd 0.55 TeBO5:0.45Eu 3+ obtained in Example 1 of this application;

[0039] Figure 3 Emission spectra of Gd 1-x TeBO5:Eu 3+ (0 < x ≤ 0.9) obtained in Examples 1, 3, 4, 5, 6, 7, 8, 9 of this application. The inset is the trend diagram of the integrated emission intensity changing with concentration;

[0040] Figure 4 For the Gd obtained in Example 1 of this application 0.55 TeBO5:0.45Eu 3+ Quantum efficiency graph;

[0041] Figure 5 For Gd in Example 1 of this application 0.55 TeBO5:0.45Eu 3+ Graph of the relationship between luminescence intensity and temperature, and the inset shows the change trend of the integrated intensity of the variable-temperature spectrum;

[0042] Figure 6 For Gd in Example 1 of this application 0.55 TeBO5:0.45Eu 3+ Chromaticity coordinate graph. Description of the drawings:

[0044] Figure 1 For Gd in Examples 1, 2, 3, 4, 5, 6, 7, 8, 9 of this application 1-x TeBO5:Eu 3+ (0≤x≤0.9) XRD patterns. The diffraction peak positions of all samples correspond exactly to those of the simulated LaTeBO5 diffraction peaks, indicating that all synthesized samples are pure phases.

[0045] Figure 2 For Gd in Example 1 of this application 0.55 TeBO5:0.45Eu 3+ Excitation and emission spectra. In Figure 2 The left half: Using a wavelength of 613 nm as the monitoring wavelength, the excitation spectrum of Gd 0.55 TeBO5:0.45Eu 3+ is obtained. A series of excitation peaks between 310 nm and 550 nm can be observed from the figure, which correspond to the 4f–4f transitions of Eu 3+ ions, namely 7 F0→ 5 H3(317 nm), 7 F0→ 5 D4(361 nm), 7 F0→ 5 L7(375 / 380 nm), 7 F0→ 5 L6(394 nm), 7 F0→ 5 D3(414 nm), 7 F0→ 5 D2(465 nm) and 7 F0→ 5D1 (525 nm) transition, where the excitation peak at 394 nm ( 7 F0 → 5 L6) is the strongest excitation peak and matches the commercial near-ultraviolet LED chips. In Figure 2 The right half: Using a wavelength of 394 nm as the excitation wavelength, the emission spectrum of Gd 0.55 TeBO5:0.45Eu 3+ is obtained. From the figure, a series of emission peaks appearing between 550 - 750 are observed, corresponding to the 3+ ions of Eu 5 D0 → 7 F1 (594 nm), 5 D0 → 7 F2 (613 / 621 nm), 5 D0 → 7 F4 (699 / 705 nm) respectively. The strongest emission peak is located at 613 nm (electric dipole transition), indicating that the Eu 3+ ions occupy the lattice sites without an inversion symmetry center in the matrix GdTeBO5.

[0046] Figure 3 These are the emission spectra of Gd 1-x TeBO5:Eu 3+ (0 < x ≤ 0.9) obtained under an excitation wavelength of 394 nm in Examples 1, 3, 4, 5, 6, 7, 8, 9 of this application. With the increase of the Eu 3+ doping concentration, the luminescence intensity gradually increases. When the doping concentration exceeds 0.45, the luminescence intensity begins to decline, indicating that the optimal doping concentration of Eu 3+ ions is 0.45.

[0047] Figure 4 These are the quantum efficiency diagrams of Gd 0.55 TeBO5:0.45Eu 3+ in Example 1 of this application. Under excitation at 394 nm, Gd 0.55 TeBO5:0.45Eu 3+ exhibits ultra-high luminescence efficiency, with an internal quantum efficiency of 95% and an external quantum efficiency of 40%, and an absorption efficiency of 34%.

[0048] Figure 5 These are the diagrams of the relationship between the luminescence intensity and temperature of Gd 0.55 TeBO5:0.45Eu 3+ in Example 1 of this application. With the increase of temperature, the position of the emission peak does not change, and the emission intensity decreases slightly. From Figure 5It can be seen from the illustration that the integrated emission intensity of the phosphor can maintain 99% and 98% of that at room temperature at 150 °C and 200 °C respectively, with almost no loss in emission intensity, approaching near-zero thermal quenching.

[0049] Figure 6 For Example 1 Gd 0.55 TeBO5:0.45Eu 3+ The chromaticity coordinate diagram of which has chromaticity coordinates located in the red light region, and the chromaticity coordinate values are (0.6504, 0.3493). Detailed implementation manners

[0050] The present application will be further described in detail below in conjunction with the accompanying drawings and embodiments, but the present application is not limited in any way. Any transformation or improvement made based on the teachings of the present application falls within the protection scope of the present application.

[0051] Embodiment

[0052] In the following embodiments, the materials and instruments used are obtained from commercial channels without special instructions; the detection methods used are existing methods without special instructions. The detection methods used are carried out according to the existing methods in the art without special instructions.

[0053] Example 1 Preparation of Gd 0.55 TeBO5:0.45Eu 3+ Phosphor

[0054] (1) Weighing: Accurately weigh 0.6646 g of Gd2O3 (purity 99.99%), 1.0640 g of TeO2 (purity 99.99%), 0.4120 g of H3BO3 (purity 99.9%), and 0.5279 g of Eu2O3 (purity 99.99%) according to the stoichiometric ratio.

[0055] (2) Grinding: Mix all the raw materials and grind them thoroughly in an agate mortar for 30 min, then put the reactants into a corundum crucible.

[0056] (3) Pre-sintering stage: Put the corundum crucible containing the reactants into a muffle furnace, set the heating program: heat from room temperature to 300 °C at a heating rate of 2 °C / min, hold at this temperature for 5 h, and finally, cool to room temperature with the furnace, take out the pre-sintered product, and grind it again for 30 min.

[0057] (4) Solid-state reaction stage: Heat the sample after re-grinding from room temperature to 740 °C at a heating rate of 2 °C / min, hold at this temperature for 48 h, then cool to room temperature at a cooling rate of 2 °C / min, and grind to obtain the sample for subsequent characterization tests.

[0058] Example 2 Preparation of GdTeBO5 matrix material

[0059] The preparation process is the same as that of Example 1, except for the different dosages of each raw material. The specific dosages of the raw materials are 1.2083 g of Gd2O3 (99.99%), 1.0640 g of TeO2 (99.99%), and 0.4120 g of H3BO3 (99.9%).

[0060] Example 3 prepares Gd 0.95 TeBO5:0.05Eu 3+ phosphor

[0061] The preparation process is the same as that of Example 1, except for the different dosages of each raw material. The specific dosages of the raw materials are 1.1479 g of Gd2O3 (99.99%), 1.0640 g of TeO2 (99.99%), 0.4120 g of H3BO3 (99.9%), and 0.0587 g of Eu2O3 (99.99%).

[0062] Example 4 prepares Gd 0.9 TeBO5:0.1Eu 3+ phosphor

[0063] The preparation process is the same as that of Example 1, except for the different dosages of each raw material. The specific dosages of the raw materials are 1.0875 g of Gd2O3 (99.99%), 1.0640 g of TeO2 (99.99%), 0.4120 g of H3BO3 (99.9%), and 0.1173 g of Eu2O3 (99.99%).

[0064] Example 5 prepares Gd 0.85 TeBO5:0.15Eu 3+ phosphor

[0065] The preparation process is the same as that of Example 1, except for the different dosages of each raw material. The specific dosages of the raw materials are 1.0271 g of Gd2O3 (99.99%), 1.0640 g of TeO2 (99.99%), 0.4120 g of H3BO3 (99.9%), and 0.1759 g of Eu2O3 (99.99%).

[0066] Example 6 prepares Gd 0.7 TeBO5:0.3Eu 3+ phosphor

[0067] The preparation process is the same as that of Example 1, except for the different dosages of each raw material. The specific dosages of the raw materials are 0.8458 g of Gd2O3 (99.99%), 1.0640 g of TeO2 (99.99%), 0.4120 g of H3BO3 (99.9%), and 0.3519 g of Eu2O3 (99.99%).

[0068] Example 7 Preparation of Gd 0.4 TeBO5:0.6Eu 3+ Phosphor

[0069] The preparation process is the same as that of Example 1, except for the different dosages of each raw material. The specific dosages of the raw materials are 0.4833 g of Gd2O3 (99.99%), 1.0640 g of TeO2 (99.99%), 0.4120 g of H3BO3 (99.9%), and 0.7039 g of Eu2O3 (99.99%).

[0070] Example 8 Preparation of Gd 0.25 TeBO5:0.75Eu 3+ Phosphor

[0071] The preparation process is the same as that of Example 1, except for the different dosages of each raw material. The specific dosages of the raw materials are 0.3021 g of Gd2O3 (99.99%), 1.0640 g of TeO2 (99.99%), 0.4120 g of H3BO3 (99.9%), and 0.8798 g of Eu2O3 (99.99%).

[0072] Example 9 Preparation of Gd 0.1 TeBO5:0.9Eu 3+ Phosphor

[0073] The preparation process is the same as that of Example 1, except for the different dosages of each raw material. The specific dosages of the raw materials are 0.1208 g of Gd2O3 (99.99%), 1.0640 g of TeO2 (99.99%), 0.4120 g of H3BO3 (99.9%), and 1.0558 g of Eu2O3 (99.99%).

[0074] Example 10

[0075] The difference from Example 1 is as follows:

[0076] (3) Pre-burning stage: Put the corundum crucible containing the reactants into the muffle furnace, set the heating program: heat from room temperature to 250 °C at a heating rate of 1 °C / min, keep it at this temperature for 4 h, and finally, cool it to room temperature with the furnace, take out the pre-burned product, and grind it again for 20 min.

[0077] (4) Solid-phase reaction stage: Heat the sample after re-grinding from room temperature to 720 °C at a heating rate of 1 °C / min, keep it at this temperature for 45 h, then cool it to room temperature at a cooling rate of 1 °C / min, grind it to obtain the sample for subsequent characterization tests.

[0078] Example 11

[0079] The differences from Example 1 are as follows:

[0080] (3) Pre-sintering stage: Place the corundum crucible containing the reactants into a muffle furnace, and set the heating program: heat from room temperature to 350 °C at a heating rate of 3 °C / min, hold at this temperature for 6 h, and finally, cool to room temperature with the furnace, take out the pre-sintered product, and grind it again for 40 min.

[0081] (4) Solid-state reaction stage: Heat the sample after re-grinding from room temperature to 760 °C at a heating rate of 3 °C / min, hold at this temperature for 50 h, then cool to room temperature at a cooling rate of 3 °C / min, and grind to obtain a sample for subsequent characterization tests.

[0082] Example 12 prepares La 0.55 TeBO5:0.45Eu 3+ phosphor

[0083] The differences from Example 1 are as follows: Gd2O3 is replaced by La2O3.

[0084] Example 13 prepares Y 0.55 TeBO5:0.45Eu 3+ phosphor

[0085] The differences from Example 1 are as follows: Gd2O3 is replaced by Y2O3.

[0086] The results obtained in Examples 10 to 13 are similar to those obtained in Example 1, and will not be repeated here.

[0087] Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A Eu 3+ doped borate tellurite red phosphor, characterized in that, The Eu 3+ The doped boron tellurite red phosphor is prepared by the following steps: After grinding the reaction raw materials, the reaction materials are heated from room temperature to 250-350 °C at a heating rate of 1-3 °C / min in an atmospheric air atmosphere, held at this temperature for 4-6 h, cooled to room temperature with the furnace, and then ground again; Under an atmospheric air atmosphere, the pre-calcined material is heated from room temperature to 720 - 760 °C at a heating rate of 1 - 3 °C / min, held at this temperature for 45 - 55 h, and then cooled to room temperature at a cooling rate of 1 - 3 °C / min to obtain Eu 3+ -doped borotellurite red phosphor; The reaction raw materials are composed of TeO2, H3BO3, Eu2O3, and Ln compounds; the Ln compound is La2O3, Y2O3, or Gd2O3; When the Ln compound is La2O3, La2O3, TeO2, H3BO3, and Eu2O3 are mixed into raw materials in a molar ratio of 1- x :2:2: x ; 0＜ x ≤0.9； When the Ln compound is Y2O3, Y2O3, TeO2, H3BO3, and Eu2O3 are mixed into raw materials in a molar ratio of 1- x :2:2: x ; 0＜ x ≤0.9； When the Ln compound is Gd2O3, Gd2O3, TeO2, H3BO3, and Eu2O3 are mixed into raw materials in a molar ratio of 1- x :2:2: x ; 0＜ x ≤0.9； The obtained Eu 3+ The chemical general formula of the boron-doped tellurite red phosphor is Ln 1-x TeBO5: x Eu 3+ , Eu 3+ The doping amount 0 < x ≤0.9; Ln is Gd 3+ , La 3+ or Y 3+ Any one.

2. Eu doped borate tellurite red phosphor according to claim 1, characterized in that, 3+ Under the excitation wavelength of 394 nm, Eu 3+ -doped borotellurite red phosphor emits red light in the range of 550-750 nm; ​ x = 0.45 and Ln is Gd 3+ When, the chromaticity coordinate values are (0.6504, 03493).

3. Eu doped borate tellurite red phosphor according to claim 1 3+ , characterized in that x = 0.45 and Ln is Gd 3+ When 3+ the integral emission intensity of Eu-doped borotellurite red phosphor at 150 °C is 99% of that at room temperature; Eu 3+ the integral emission intensity of the doped phosphor at 200 °C is 98% of that at room temperature.

4. Eu doped borate tellurite red phosphor according to claim 1 3+ characterized in that x = 0.45 and Ln is Gd 3+ When 3+ For the Eu-doped borotellurite red phosphor, the internal quantum efficiency reaches 95%, the external quantum efficiency reaches 40%, and the absorption efficiency is 34% under the excitation wavelength of 394 nm.

5. The Eu 3+ doped borate tellurite red phosphor, characterized in that, The re-grinding operation is carried out for 20-40 min.

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