Europium-doped germanate red fluorescent powder and preparation method thereof

Abstract

The present application relates to a kind of europium doped germanate red fluorescent powder and preparation method, and europium doped germanate red fluorescent powder is prepared from lithium carbonate, sodium carbonate, germanium oxide and europium oxide, and the molar ratio of raw material is 1:1:8:(0.025 to 0.1), and the structural formula is LiNaGe4O9:xEu 3+ The preparation method is to add solid-phase reaction raw materials to ethanol to grind, and dry precursor mixed powder is obtained by natural air drying in air;The precursor mixed powder is placed in a tube furnace, heated to 800 DEG C at 5 DEG C / min, and calcined for 8 hours;After the product is naturally cooled to room temperature with the tube furnace, the finished product is obtained by grinding, the present application provides an asymmetric coordination environment using the flexible network structure of germanium-oxygen tetrahedron, reduces the matrix phonon energy through the strong covalence of germanium-oxygen bond, suppresses non-radiative transition and concentration quenching by combining the doping concentration within the defined interval, and improves the quantum efficiency and red light emission intensity of fluorescent powder.

Description

Technical Field

[0001] This invention relates to the field of luminescent materials technology, specifically to a europium-doped germanate red phosphor and its preparation method. Background Technology

[0002] Rare-earth inorganic luminescent materials have wide applications in solid-state lighting and display technologies. Red phosphors are a component material of white light-emitting diodes and display devices.

[0003] In existing optoelectronic applications, red phosphors are typically used in conjunction with excitation sources. Conventional red phosphors often employ inorganic compounds such as silicates, aluminates, or phosphates as the crystal matrix, and use rare-earth ions as luminescent centers. In these conventional systems, the matrix lattice acts as the carrier of the luminescent ions, and its network structure determines the optical process by which the luminescent ions absorb excitation energy and convert it into photons for output.

[0004] Existing red light luminescence systems suffer from low internal quantum efficiency. Conventional matrix materials have high phonon energies, which increase lattice vibrations during luminescence, causing energy loss through non-radiative transitions at the excited-state luminescent centers. Furthermore, existing matrix lattices struggle to provide suitable asymmetric coordination environments for doped ions, limiting the intensity of electric dipole transitions. These limitations of lattice environment and phonon energy result in weak red light emission intensity from red phosphors, leading to low internal quantum efficiency in the luminescence system. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a europium-doped germanate red phosphor and its preparation method, which solves the problems of excessively high phonon energy and excessively high coordination environment symmetry in existing conventional inorganic matrix luminescent materials.

[0006] To achieve the above objectives, the present invention provides the following technical solution: The first aspect of the present invention provides a europium-doped germanate red phosphor, which is prepared from solid-state reaction raw materials; the solid-state reaction raw materials include lithium carbonate, sodium carbonate, germanium oxide and europium oxide; the molar ratio of lithium carbonate, sodium carbonate, germanium oxide and europium oxide in the solid-state reaction raw materials is 1:1:8:(0.025 to 0.1).

[0007] The structural formula of europium-doped germanate red phosphor is LiNaGe4O9:xEu 3+ In the structural formula, Li represents lithium, Na represents sodium, Ge represents germanium, O represents oxygen, and Eu represents... 3+ This represents a europium ion with three positive charges, and x represents the doping concentration of the europium ion, with the value of the doping concentration x ranging from 0.025 to 0.1.

[0008] Preferably, the molar ratio of lithium carbonate, sodium carbonate, germanium oxide and europium oxide in the solid-phase reaction raw materials is 1:1:8:0.025, or 1:1:8:0.03, or 1:1:8:0.05, or 1:1:8:0.1.

[0009] The second aspect of this invention provides a method for preparing europium-doped germanate red phosphor, used to prepare the europium-doped germanate red phosphor provided in the first aspect of this invention. The method for preparing the europium-doped germanate red phosphor employs a high-temperature solid-state synthesis process and includes the following steps: S101. Weigh the corresponding solid reaction raw materials according to the molar ratio of the solid reaction raw materials; S102. Weigh out lithium carbonate, sodium carbonate, germanium oxide and europium oxide and put them into an agate mortar; add anhydrous ethanol into the agate mortar as a grinding medium; grind the material inside the agate mortar to make lithium carbonate, sodium carbonate, germanium oxide and europium oxide mixed evenly. S201. Place the material containing anhydrous ethanol in an air environment for natural air drying; allow the anhydrous ethanol to evaporate through airflow to obtain a dry precursor mixed powder. S202. Load the dried precursor mixed powder into an alumina crucible; move the alumina crucible containing the precursor mixed powder into a tube furnace; control the tube furnace to heat from room temperature to the target reaction temperature; S203. After the temperature inside the tube furnace reaches the target reaction temperature, heat the material; control the material to continue to undergo solid-phase reaction at the target reaction temperature. S301. After the heat preservation treatment is completed, stop the heating input of the tube furnace; use natural cooling method to allow the product generated by the solid-phase reaction to cool to room temperature synchronously with the tube furnace; open the tube furnace and collect the cooled product, which is in block form. S302. The collected blocky product is put back into the mortar and ground; the blocky product is crushed by mechanical force to transform it into powder particles. After grinding, europium-doped germanate red phosphor is obtained.

[0010] Preferably, in step S102, the grinding time for grinding the material inside the agate mortar is set to 1 to 2 hours.

[0011] Preferably, in step S202, an air atmosphere is maintained inside the tube furnace; the specific control method for controlling the tube furnace to heat from room temperature to the target reaction temperature is: controlling the tube furnace to heat from room temperature to the target reaction temperature of 800°C at a heating rate of 5°C / min.

[0012] Preferably, in step S203, the specific control method for controlling the material to continuously undergo a solid-phase reaction under the temperature environment of the target reaction temperature is: the heat preservation time for heat preservation treatment of the material is set to 8 hours.

[0013] This invention provides a europium-doped germanate red phosphor and its preparation method. It has the following beneficial effects: 1. This invention uses germanate compounds as the luminescent matrix material and utilizes the flexible network structure composed of germanium-oxygen tetrahedra (GeO4) to provide an asymmetric coordination environment for europium ions, directly enhancing the electric dipole transition intensity of europium ions. At the same time, it reduces the phonon energy of the crystal matrix by leveraging the strong covalentity of germanium-oxygen bonds, suppressing nonradiative transition processes, thereby achieving the technical effects of improving the quantum efficiency of red phosphors and enhancing the red light emission intensity.

[0014] 2. By defining the europium ion doping concentration within the range of 0.025 to 0.1, the present invention enables the luminescent system to achieve an energy-matched state, overcoming the problem of limited energy transfer caused by excessively low activator concentration. At the same time, it avoids the concentration quenching effect and photon self-absorption phenomenon caused by excessively high doping concentration, blocks the generation of impurity phases caused by excessive ions, and achieves the technical effect of maintaining the purity of the single crystal phase of red phosphor and ensuring luminescent performance.

[0015] 3. This invention employs a high-temperature solid-phase synthesis process combined with specific raw material ratios and anhydrous ethanol-assisted grinding to achieve a uniform mixing state of the solid-phase reaction raw materials. This ensures that the materials undergo sufficient solid-phase reaction and lattice reconstruction under a programmed temperature-controlled constant-temperature calcination environment. Furthermore, natural cooling is used after calcination to release internal thermal stress, thereby achieving the technical effect of stably preparing high-crystallinity red fluorescence. Attached Figure Description

[0016] Figure 1 X-ray diffraction pattern of europium-doped germanate red phosphor prepared in Example 1; Figure 2 Scanning electron microscope image of the europium-doped germanate red phosphor prepared in Example 2; Figure 3 The fluorescence decay curve (upper half) of the europium-doped germanate red phosphor prepared in Example 3. Figure 4 X-ray photoelectron spectrum of europium-doped germanate red phosphor prepared in Example 4; Figure 5 The quantum efficiency spectrum of the europium-doped germanate red phosphor prepared in Example 5 is shown. Figure 6 The X-ray diffraction pattern of the phosphor prepared in Comparative Example 1; Figure 7The excitation spectra of the phosphors prepared in Examples 1-5 and Comparative Example 2 are shown. Figure 8 The emission spectra of the phosphors prepared in Examples 1-5 and Comparative Example 2 are shown. Detailed Implementation

[0017] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Please see the appendix Figure 1 This invention provides a rare earth metal europium ion-doped germanate compound red phosphor and its preparation method.

[0019] The overall workflow for preparing rare earth metal europium ion-doped germanate compound red phosphors consists of the following steps.

[0020] S1. Obtain the raw materials required for synthesizing rare earth metal europium ion-doped germanate compound red phosphor, mix the raw materials and grind them until uniform.

[0021] S2. Dry the material that has been ground to a uniform state, place the dried material into a tube furnace for calcination, and keep it at the target temperature for a period of time.

[0022] S3. After the heat preservation is completed, the material is cooled to room temperature. The material cooled to room temperature is then ground a second time to obtain rare earth metal europium ion-doped germanate compound red phosphor.

[0023] The structural formula of the red phosphor is LiNaGe4O9:xEu 3+ In the structural formula, Li represents lithium, Na represents sodium, Ge represents germanium, O represents oxygen, and Eu represents... 3+ The variable x represents a europium ion with three positive charges, and x represents the doping concentration. In the structural formula, the variable x represents the doping concentration of the rare-earth metal europium ions, and the value of x is defined as 0.025 ≤ x ≤ 0.1. The raw materials for preparing rare-earth metal europium ion-doped germanate compound red phosphors include lithium carbonate, sodium carbonate, germanium oxide, and europium oxide. The molar ratio of the raw materials is limited to lithium carbonate:sodium carbonate:germanium oxide:europium oxide = 1:1:8:(0.025 to 0.1).

[0024] The rare-earth metal europium ion-doped germanate compound red phosphor provided in this embodiment of the invention is prepared using a high-temperature solid-state synthesis process. The specific process steps are broken down as follows: S101. Weigh the corresponding solid-phase reaction raw materials according to the molar ratio of the precursor materials. The solid-phase reaction raw materials include lithium carbonate, sodium carbonate, germanium oxide, and europium oxide. The molar ratio of the precursor materials is set as lithium carbonate:sodium carbonate:germanium oxide:europium oxide = 1:1:8:(0.025 to 0.1).

[0025] S102. Weigh out lithium carbonate, sodium carbonate, germanium oxide, and europium oxide and place them into an agate mortar. Add anhydrous ethanol as a grinding medium to the inside of the agate mortar. Grind the materials inside the agate mortar for 1 to 2 hours to ensure that the lithium carbonate powder, sodium carbonate powder, germanium oxide powder, and europium oxide powder are mixed evenly.

[0026] S201. The material containing anhydrous ethanol is placed in an air environment for natural air drying. The anhydrous ethanol is evaporated by airflow to obtain a dry precursor mixed powder.

[0027] S202. Load the dried precursor mixture powder into an alumina crucible. Transfer the alumina crucible containing the precursor mixture powder into a tube furnace, maintaining an air atmosphere inside the tube furnace. Control the tube furnace to heat from room temperature to the target reaction temperature of 800℃ at a heating rate of 5℃ / min.

[0028] S203. When the internal temperature of the tubular furnace reaches 800℃, the material is subjected to heat preservation treatment. The material is controlled to continuously undergo solid-phase reaction at a temperature of 800℃, and the heat preservation time is set to 8 hours.

[0029] S301. After the heat preservation treatment is completed, stop the heating input of the tube furnace. Use natural cooling to allow the product generated by the solid-phase reaction to cool to room temperature synchronously with the tube furnace. Open the tube furnace and collect the cooled product, which will be in a blocky form.

[0030] S302. The collected blocky product is put back into the mortar and ground. The blocky product is crushed by mechanical force, turning it into powder particles. After grinding, the rare earth metal europium ion-doped germanate compound red phosphor is obtained.

[0031] Example: Example 1

[0032] This embodiment provides a multi-gradient formulation for preparing a rare-earth metal europium ion-doped germanate compound red phosphor. The red phosphor has the structural formula LiNaGe4O9:xEu. 3+ In the structural formula, Li represents lithium, Na represents sodium, Ge represents germanium, O represents oxygen, and Eu represents... 3+ This represents a europium ion with three positive charges, and x represents the doping concentration variable.

[0033] Press Eu 3+ Four sets of raw materials were prepared with doping concentration variable x taking values ​​of 0.025, 0.03, 0.05, and 0.1 respectively. The specific composition and dosage of raw materials for each group are as follows: Group 1 (x=0.025): Weigh out 0.0739g of lithium carbonate, 0.1060g of sodium carbonate, 0.8371g of germanium oxide, and 0.0088g of europium oxide; Group 2 (x=0.03): Weigh out 0.0739g of lithium carbonate, 0.1060g of sodium carbonate, 0.8371g of germanium oxide, and 0.0106g of europium oxide; Group 3 (x=0.05): Weigh out 0.0739g of lithium carbonate, 0.1060g of sodium carbonate, 0.8371g of germanium oxide, and 0.0176g of europium oxide; Group 4 (x=0.1): Weigh out 0.0739g of lithium carbonate, 0.1060g of sodium carbonate, 0.8371g of germanium oxide, and 0.0352g of europium oxide.

[0034] The four sets of raw materials were physically mixed separately. Each mixed raw material was then placed in an agate mortar, and anhydrous ethanol was added as the grinding medium. The grinding time was controlled to be 1 hour. After grinding, the material containing anhydrous ethanol was placed in an air environment to air dry naturally, allowing the anhydrous ethanol to evaporate and obtain a dry powder.

[0035] The air-dried powders were placed in corundum crucibles and then transferred to a tube furnace. Under air atmosphere, the temperature was programmed to rise to 800℃ at a rate of 5℃ / min, and then calcined at 800℃ for 8 hours. After calcination, the product was cooled to room temperature simultaneously with the tube furnace to obtain block products. The block products were then ground to obtain four different doping concentrations of LiNaGe4O9:xEu. 3+ Red fluorescent powder.

[0036] Example 2

[0037] This embodiment provides a structure with the formula LiNaGe4O9:0.025Eu. 3+ The preparation process of red phosphor.

[0038] Weigh out 0.0088 g of europium oxide, 0.0739 g of lithium carbonate, 0.1060 g of sodium carbonate, and 0.8371 g of germanium oxide. Mix the lithium carbonate, sodium carbonate, germanium oxide, and europium oxide together. Place the mixture in an agate mortar and grind it for 1 hour with anhydrous ethanol as the grinding medium. After grinding, air dry to obtain a powder.

[0039] The air-dried powder was placed in a corundum crucible and then placed in a tube furnace. The temperature was increased to 800℃ at a rate of 5℃ / min in air atmosphere and calcined at this temperature for 8 hours. The calcined product was cooled to room temperature with the tube furnace, and the blocky product was extracted and ground to obtain LiNaGe4O9:0.025Eu. 3+ Red fluorescent powder.

[0040] Example 3

[0041] This embodiment provides a structure with the formula LiNaGe4O9:0.03Eu. 3+ The preparation process of red phosphor.

[0042] Weigh out 0.0106 g of europium oxide, 0.0739 g of lithium carbonate, 0.1060 g of sodium carbonate, and 0.8371 g of germanium oxide. Mix the above raw materials and transfer them to an agate mortar. Grind with anhydrous ethanol for 1 hour. Allow the ground material to air dry naturally.

[0043] The air-dried powder was placed in a corundum crucible and calcined in a tube furnace in air at a rate of 5 °C / min to 800 °C for 8 h. After cooling to room temperature, the blocky product was collected and ground to obtain LiNaGe4O9:0.03Eu. 3+ Red fluorescent powder.

[0044] Example 4

[0045] This embodiment provides a structure with the formula LiNaGe4O9:0.05Eu. 3+ The preparation process of red phosphor.

[0046] Weigh out 0.0176 g of europium oxide, 0.0739 g of lithium carbonate, 0.1060 g of sodium carbonate, and 0.8371 g of germanium oxide and mix them. Place the mixture in an agate mortar, add anhydrous ethanol and grind for 1 hour, then air dry naturally.

[0047] The obtained powder was placed in an alumina crucible and fed into a tube furnace. The temperature was set to a heating rate of 5℃ / min and heated to 800℃, where it was calcined for 8 hours. After the product cooled to room temperature in the furnace, the blocky product was removed and ground to obtain LiNaGe4O9:0.05Eu. 3+ Red fluorescent powder.

[0048] Example 5

[0049] This embodiment provides a structure with the formula LiNaGe4O9:0.1Eu. 3+ The preparation process of red phosphor.

[0050] Weigh out 0.0352 g of europium oxide, 0.0739 g of lithium carbonate, 0.1060 g of sodium carbonate, and 0.8371 g of germanium oxide and mix them. Add anhydrous ethanol to an agate mortar and grind the mixture for 1 hour. After grinding, allow it to air dry naturally to obtain a dry powder.

[0051] The powder was transferred to a corundum crucible and placed in a tube furnace. Under air atmosphere, the temperature was increased to 800℃ at a rate of 5℃ / min and held for 8 hours. After the calcined product cooled naturally to room temperature, the resulting blocky product was ground to obtain LiNaGe4O9:0.1Eu. 3+ Red fluorescent powder.

[0052] Comparative example: Comparative Example 1 Comparative Example 1 illustrates the technical effect when the doping concentration exceeds the set upper limit. The target red phosphor in Comparative Example 1 has the structural formula LiNaGe4O9:0.2Eu. 3+ .

[0053] Weigh out 0.0704 g of europium oxide, 0.0739 g of lithium carbonate, 0.1060 g of sodium carbonate, and 0.8371 g of germanium oxide. Mix the lithium carbonate, sodium carbonate, germanium oxide, and europium oxide. Place the mixture into an agate mortar, add anhydrous ethanol as the grinding medium, and grind for 1 hour. After grinding, allow the material containing anhydrous ethanol to air dry naturally to obtain a powder.

[0054] The powdered material was placed in an alumina crucible and then placed in a tube furnace. Under air atmosphere, the temperature was programmed to rise to 800°C at a rate of 5°C / min, and then calcined at 800°C for 8 hours. After calcination, the heat input was stopped, and the calcined product was cooled to room temperature in the tube furnace. The resulting blocky product was then removed and ground to obtain the structure LiNaGe4O9:0.2Eu. 3+ Fluorescent powder.

[0055] The X-ray diffraction characterization and spectral test results show that the excessive europium ions caused obvious impurity phase diffraction peaks in the product due to the doping concentration of 0.2 exceeding the upper limit of the range of 0.025 to 0.1, and the crystal phase purity was destroyed.

[0056] Comparative Example 2 Comparative Example 2 illustrates the technical effect when the doping concentration is below a set lower limit. The target red phosphor in Comparative Example 2 has the structural formula LiNaGe4O9:0.02Eu. 3+ .

[0057] Weigh out 0.0070 g of europium oxide, 0.0739 g of lithium carbonate, 0.1060 g of sodium carbonate, and 0.8371 g of germanium oxide. Mix the four solid raw materials and place them in an agate mortar. Add anhydrous ethanol and mechanically grind the materials for 1 hour. Allow the ground materials to air dry naturally to obtain a dry powder.

[0058] The dried powder was transferred to a corundum crucible and then into a tube furnace. In an air atmosphere, the tube furnace was heated to 800°C at a heating rate of 5°C / min and calcined at 800°C for 8 hours. The calcined product was allowed to cool naturally to room temperature within the tube furnace. The lumpy product at room temperature was collected and ground to obtain the structure LiNaGe4O9:0.02Eu. 3+ Fluorescent powder.

[0059] Tests and analyses show that the luminescence performance of the obtained rare earth phosphor is significantly reduced because the doping concentration of 0.02 is below the lower limit of the range of 0.025 to 0.1.

[0060] To verify the physical structure and luminescent properties of the prepared rare-earth metal europium ion-doped germanate compound red phosphor, the LiNaGe4O9:xEu phosphor obtained in the examples was tested. 3+ The red phosphor product was subjected to microscopic characterization and optical property testing. (LiNaGe4O9:xEu) 3+ In this context, Li represents lithium, Na represents sodium, Ge represents germanium, O represents oxygen, and Eu represents... 3+ This represents a europium ion with three positive charges, and x represents the doping concentration of the europium ion.

[0061] Refer to the instruction manual. Figure 1 , attached Figure 1 X-ray diffraction pattern of the red phosphor prepared for the example. (From Appendix) Figure 1 It can be seen that when the doping concentration x is in the range of 0.025 to 0.1, all diffraction peaks of the red phosphor prepared in the examples correspond to the characteristic diffraction peaks of the LiNaGe4O9 standard card. (Appendix) Figure 1 No impurity diffraction peaks were observed. The test results indicate that europium ions are incorporated into the lattice network of the germanate matrix, and the red phosphor prepared in the example possesses a single phase structure.

[0062] Refer to the instruction manual. Figure 6 , attached Figure 6 The X-ray diffraction pattern of the control group phosphor with excessive doping concentration is shown in the accompanying diagram. Figure 1 With appendix Figure 6It can be seen that the control group phosphor, which exceeded the upper limit of the doping concentration limit, showed impurity phase diffraction peaks in the X-ray diffraction pattern. The comparison of diffraction patterns confirmed that limiting the doping concentration x to the range of 0.025 to 0.1 is a necessary condition for maintaining the pure phase structure of the product.

[0063] Refer to the instruction manual. Figure 2 , attached Figure 2 The image shows the scanning electron microscope (SEM) morphology of the red phosphor prepared for this example. Under the SEM, the rare-earth phosphor obtained in this example can be clearly seen, exhibiting an irregular, blocky crystal structure.

[0064] Refer to the instruction manual. Figure 4 , attached Figure 4 The X-ray photoelectron spectroscopy (XPS) spectrum of the red phosphor prepared for this example is shown. The XPS data confirmed the presence of sodium, germanium, oxygen, and europium in the red phosphor. The test results confirmed that europium maintained its trivalent state during the high-temperature solid-state calcination of the precursor.

[0065] Refer to the instruction manual. Figure 7 With appendix Figure 8 , attached Figure 7 The excitation spectrum of the red phosphor prepared for the example is attached. Figure 8 The emission spectrum of the red phosphor prepared for this example is shown. Spectroscopic testing demonstrates that the red phosphor exhibits characteristic narrow-band emission in the 550-750 nm wavelength range, and its emission intensity changes systematically with variations in doping concentration.

[0066] Refer to the instruction manual. Figure 3 , attached Figure 3 The upper part shows the fluorescence decay curve of the red phosphor prepared in the example.

[0067] Refer to the instruction manual. Figure 5 , attached Figure 5 The quantum efficiency spectrum of the red phosphor prepared for the example.

[0068] For the specific testing procedures to obtain the above-mentioned microscopic characterization and spectral maps, those skilled in the art can use conventional physical characterization and optical testing methods in the field of materials science. The corresponding specific testing procedures are well-known technologies in this field and will not be elaborated here.

[0069] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A europium-doped germanate red phosphor, characterized in that, The europium-doped germanate red phosphor has the structural formula LiNaGe4O9:xEu. 3+ Where 0.025≤x≤0.1; the europium-doped germanate red phosphor is prepared from solid-state reaction raw materials, which include lithium carbonate, sodium carbonate, germanium oxide and europium oxide, and the molar ratio of lithium carbonate, sodium carbonate, germanium oxide and europium oxide in the solid-state reaction raw materials is 1:1:8:(0.025 to 0.1).

2. A method for preparing europium-doped germanate red phosphor, used to prepare the europium-doped germanate red phosphor as described in claim 1, characterized in that, The preparation method of europium-doped germanate red phosphor adopts a high-temperature solid-state synthesis process, and the preparation method includes the following steps: S101. Weigh the corresponding solid reaction raw materials according to the molar ratio of the solid reaction raw materials; S102. Weigh out lithium carbonate, sodium carbonate, germanium oxide and europium oxide and put them into an agate mortar; add anhydrous ethanol into the agate mortar as a grinding medium; grind the material inside the agate mortar to make lithium carbonate, sodium carbonate, germanium oxide and europium oxide mixed evenly. S201. Place the material containing anhydrous ethanol in an air environment for natural air drying; allow the anhydrous ethanol to evaporate through airflow to obtain a dry precursor mixed powder. S202. Load the dried precursor mixed powder into an alumina crucible; transfer the alumina crucible containing the precursor mixed powder into a tube furnace; control the tube furnace to heat from room temperature to the target reaction temperature. S203. After the internal temperature of the tubular furnace reaches the target reaction temperature, the material is kept warm; the material is controlled to continue to undergo solid-phase reaction under the temperature environment of the target reaction temperature. S301. After the heat preservation treatment is completed, stop the heating input of the tube furnace; use natural cooling method to allow the product generated by the solid-phase reaction to cool to room temperature synchronously with the tube furnace; open the tube furnace and collect the cooled product, which is in block form. S302. The collected blocky product is put back into the mortar and ground; the blocky product is crushed by mechanical force to transform it into powder particles. After grinding, europium-doped germanate red phosphor is obtained.

3. The method for preparing europium-doped germanate red phosphor according to claim 2, characterized in that, In step S102, during the grinding operation of the material inside the agate mortar, the grinding time is set to 1 to 2 hours.

4. The method for preparing europium-doped germanate red phosphor according to claim 2, characterized in that, In step S202, an air atmosphere is maintained inside the tube furnace; the specific control method for controlling the tube furnace to heat from room temperature to the target reaction temperature is as follows: the tube furnace is controlled to heat from room temperature to the target reaction temperature of 800℃ at a heating rate of 5℃ / min.

5. The method for preparing europium-doped germanate red phosphor according to claim 2, characterized in that, In step S203, the specific control method for controlling the material to continuously undergo a solid-phase reaction under the temperature environment of the target reaction temperature is as follows: the heat preservation time for heat preservation treatment of the material is set to 8 hours.

6. The europium-doped germanate red phosphor according to claim 1, characterized in that, The molar ratio of lithium carbonate, sodium carbonate, germanium oxide and europium oxide in the solid-phase reaction feedstock is 1:1:8:0.

025.

7. The europium-doped germanate red phosphor according to claim 1, characterized in that, The molar ratio of lithium carbonate, sodium carbonate, germanium oxide and europium oxide in the solid-phase reaction feedstock is 1:1:8:0.

03.

8. The europium-doped germanate red phosphor according to claim 1, characterized in that, The molar ratio of lithium carbonate, sodium carbonate, germanium oxide and europium oxide in the solid-phase reaction feedstock is 1:1:8:0.

05.

9. The europium-doped germanate red phosphor according to claim 1, characterized in that, The molar ratio of lithium carbonate, sodium carbonate, germanium oxide and europium oxide in the solid-phase reaction feedstock is 1:1:8:0.1.

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