Erbium-ytterbium-doped Na2Ta8O21 up-conversion fluorescent powder and preparation method thereof

Abstract

The invention discloses erbium and ytterbium doped Na2Ta8O21 up-conversion fluorescent powder and a preparation method thereof, Na2Ta8O21 is used as a matrix, and Er < 3 + > and Yb < 3 + > are doped in the matrix. The preparation method comprises the following steps: by taking Na2SO4 and K2SO4 as solvents, firstly synthesizing hexagonal-phase Na2Ta4O11: Er < 3 + > / Yb < 3 + > fluorescent powder through a molten salt method, and carrying out heat treatment by taking Na2Ta4O11: Er < 3 + > / Yb < 3 + > as a precursor, so as to prepare the Na2Ta8O21: Er < 3 + > / Yb < 3 + > single-phase material. Under the excitation of 980nm laser, the green up-conversion fluorescence integral intensity of Na2Ta8O21: Er < 3 + > / Yb < 3 + > is 16 times that of Na2Ta4O11: Er < 3 + > / Yb < 3 + >. In addition, the Na2Ta8O21: Er < 3 + > / Yb < 3 + > structure is analyzed for the first time and belongs to a tetragonal tungsten bronze phase.

Description

Technical Field

[0001] This invention relates to the field of upconversion phosphor technology, and more specifically, to an erbium-ytterbium-doped Na₂Ta₈O₃. 21 Upconversion phosphor and its preparation method. Background Technology

[0002] Upconversion refers to the process of absorbing multiple low-energy photons and emitting a single high-energy photon, exhibiting wavelength conversion properties. Rare-earth ions, due to their long-lived, stepped energy levels, can be doped into suitable matrices to obtain upconversion phosphor materials. The fluorescence efficiency of upconversion is affected by factors such as the phonon energy of the matrix and the distribution of rare-earth ion doping within the matrix. Tantalates are considered excellent matrix choices due to their low phonon energy and high chemical stability. Among them, Na₂Ta₈O₃... 21 It has been found in the recrystallization process of some glass materials, but it is difficult to prepare using solid-state sintering. Therefore, a method for preparing single-phase Na₂Ta₈O was developed. 21 Phosphor is essential. Additionally, Na₂Ta₈O 21 The structure is still inconclusive; some researchers believe it to be a perovskite structure, and further structural analysis is urgently needed. Summary of the Invention

[0003] The purpose of this invention is to overcome the above-mentioned defects in the prior art and provide an erbium-ytterbium-doped Na₂Ta₈O₃. 21 Upconversion phosphor and its preparation method: This invention first synthesizes Na2Ta4O using Na2SO4 and K2SO4 as solvents via a molten salt method. 11 :Er 3+ / Yb 3+ The phosphor, after being subjected to heat treatment, can be used to obtain Na2Ta4O. 11 :Er 3+ / Yb 3+ Transformation into single-phase Na2Ta8O 21 :Er 3+ / Yb 3+ Under 980nm laser excitation, Na₂Ta₈O 21 :Er 3+ / Yb 3+ The green upconversion fluorescence integral intensity of Na2Ta4O 11 :Er 3+ / Yb 3+ 16 times that of Na₂Ta₈O. Comparative experiments prove that Na₂Ta₈O 21 :Er 3+ / Yb 3+ It is impossible to prepare Na2Ta8O using only Na2SO4 / K2SO4 as a solvent via a molten salt method without heat treatment.21 :Er 3+ / Yb 3+ It also cannot be prepared by high-temperature solid-state sintering.

[0004] To achieve the above objectives, the technical solution of the present invention is as follows: An erbium-ytterbium-doped Na₂Ta₈O 21 The preparation method of upconversion phosphor includes the following steps: S1, according to the chemical formula Na a Er b Yb c Ta4O 11 ZhongNa + Er 3+ Yb 3+ Ta 5+ The molar ratio of sodium source, tantalum source, erbium source and ytterbium source is weighed and mixed to obtain mixed raw material A; where a+b+c=2. S2. Place the mixed raw material A into a mortar and add wet grinding media for grinding. Then add Na2SO4 and K2SO4 in a molar ratio of 1:1 and mix to obtain mixed raw material B. S3. The mixed raw material B is calcined at 1000°C for 2 hours. After cooling, the calcined material is soaked in deionized water, and the Na2SO4 and K2SO4 are removed by filtration to obtain Na2Ta4O. 11 :Er 3+ / Yb 3+ Single-phase materials; S4, the Na2Ta4O 11 :Er 3+ / Yb 3+ Single-phase material was heat-treated at 1500℃ to obtain Na₂Ta₈O. 21 :Er 3+ / Yb 3+ Single-phase material.

[0005] Optionally, in step S1, Na + Er 3+ Yb 3+ Ta 5+ The molar ratio is 1.94:0.02:0.04:4.

[0006] Optionally, in step S1, the sodium source is NaCO3; the tantalum source is Ta2O5; the erbium source is Er2O3; the ytterbium source is Yb2O3; and the purity of NaCO3, Er2O3, Yb2O3, and Ta2O5 is 99.0-99.9%.

[0007] Optionally, in step S2, the grinding time is 30 min; the molar ratio of Na2SO4, K2SO4 and the mixed raw materials is 6:6:1; and the wet grinding medium is ethanol.

[0008] Optionally, in step S3, the Na2Ta4O 11 :Er 3+ / Yb 3+ Single-phase materials have a hexagonal phase structure.

[0009] Optionally, in step S4, the erbium-ytterbium doped Na₂Ta₈O 21 The upconversion phosphor has a tetragonal tungsten bronze phase structure.

[0010] This invention also discloses an erbium-ytterbium-doped Na₂Ta₈O₃ prepared by the method described above. 21 Upconversion phosphor, wherein the erbium-ytterbium doped Na₂Ta₈O 21 upconversion phosphor with Na2Ta8O 21 The matrix is ​​doped with Er. 3+ and Yb 3+ The erbium-ytterbium doped Na₂Ta₈O 21 The general chemical formula of upconversion phosphor is Na a Er b Yb c Ta8O 21 , where a+b+c=2.

[0011] Optionally, the erbium-ytterbium doped with Na₂Ta₈O 21 The general chemical formula of upconversion phosphor is Na a Er b Yb c Ta8O 21 , where a=1.94, b=0.02, c=0.04.

[0012] Optionally, the erbium-ytterbium doped with Na₂Ta₈O 21 The upconversion phosphor has a tetragonal tungsten bronze phase structure.

[0013] Implementing the embodiments of the present invention will have the following beneficial effects: This invention utilizes Na₂Ta₈O with a layered structure and a non-centrosymmetric luminescent center. 21 Matrix for Er 3+ / Yb 3+ Ion co-doping, using Er 3+ / Yb 3+ Replace Na + Lattice site. Hexagonal phase Na₂Ta₄O was first synthesized via a molten salt method using Na₂SO₄ and K₂SO₄ as solvents. 11:Er 3+ / Yb 3+ Phosphor, in the form of Na2Ta4O 11 :Er 3+ / Yb 3+ Heat treatment of the precursor to achieve Na2Ta4O 11 :Er 3 + / Yb 3+ The structure transforms into Na2Ta8O 21 :Er 3+ / Yb 3+ Under 980 nm laser excitation, Na₂Ta₈O 21 :Er 3+ / Yb 3+ The green upconversion fluorescence integral intensity of Na2Ta4O 11 :Er 3+ / Yb 3+ 16 times.

[0014] Compared to solid-state reaction and direct molten salt methods, this invention utilizes Na₂SO₄ / K₂SO₄ as a solvent to prepare samples via molten salt method, followed by further heat treatment, to synthesize single-phase Na₂Ta₈O. 21 Structure. Comparative experiments demonstrate that Na₂Ta₈O 21 :Er 3+ / Yb 3+ It is impossible to prepare Na2Ta8O using only Na2SO4 / K2SO4 as a solvent via a molten salt method without heat treatment. 21 :Er 3+ / Yb 3+ It also cannot be prepared by high-temperature solid-state sintering.

[0015] Furthermore, this invention is the first to study Na2Ta8O 21 :Er 3+ / Yb 3+ The structure was analyzed and identified as belonging to the tetragonal tungsten bronze phase (TTB). Yb 3+ and Er 3+ Energy transfer between them is a 1D linear combination of 2D layers, distributed within a local area. In Na₂Ta₈O₂ 21 :Er 3 + / Yb 3+ In the middle, an Er 3+ There are a maximum of 6 Yb around. 3+ In Na2Ta4O 11 :Er 3+ / Yb 3+ In the middle, an Er 3+ There are at most 3 Yb around. 3+ . Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 The figures show the XRD test results of embodiments 1-7 of this invention.

[0018] Figure 2 The images show the XRD test results of Comparative Examples 1-2 disclosed in this invention.

[0019] Figure 3 This is a SEM morphology image of Embodiment 1 of the present invention.

[0020] Figure 4 This is a SEM morphology image of Embodiment 7 of the present invention.

[0021] Figure 5 The upconversion fluorescence spectra of Examples 1-7 of this invention under 980nm laser excitation are shown.

[0022] Figure 6 The upconversion fluorescence spectra of Examples 1-2 under 980nm laser excitation are shown in Embodiment 7 of the present invention.

[0023] Figure 7 The result is the XRD refinement result of Example 7.

[0024] Figure 8 Na2Ta8O obtained after XRD refinement 21 :Er 3+ / Yb 3+ Structural diagram.

[0025] Figure 9 a is Na2Ta4O 11 :Er 3+ / Yb 3+ A schematic diagram of the unit cell structure. Figure 9 b is Er 3+ / Yb 3+ Replace Na + A schematic diagram of the planar distribution of grid cells. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will be described in conjunction with the appendices in the embodiments of the present invention. Figure 1-9The technical solutions in the embodiments of the present invention are clearly and completely described herein. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. 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.

[0027] Example 1: Na2Ta4O in this embodiment 11 :Er 3+ / Yb 3+ The preparation method of single-phase materials includes the following steps: S1: Take 0.2327 g of raw materials NaCO3, 2 g of Ta2O5, 0.0087 g of Er2O3, and 0.0178 g of Yb2O3; wherein the molar ratio of each raw material is based on Na + Er 3+ Yb 3+ Ta 5+ =1.94:0.02:0.04:4.

[0028] S2: After mixing the raw materials, add ethanol to the mortar and grind for 30 minutes.

[0029] S3: After grinding, add Na2SO4 and K2SO4 powders in a molar ratio of 1:1 to the mixed raw materials. The molar ratio of Na2SO4 and K2SO4 to the reactants is 6:6:1. Then mix evenly.

[0030] S4: Place the raw material into a muffle furnace and hold it at 1000℃ for 2 hours. Immediately remove the crucible and cool it in an atmospheric environment.

[0031] S5: Soak the calcined material in deionized water, and remove Na2SO4 and K2SO4 by suction filtration to obtain Na2Ta4O. 11 :Er 3+ / Yb 3+ Single-phase material.

[0032] Example 2: The material preparation method in this embodiment includes the following steps: S1: Take 0.2327 g of raw materials NaCO3, 2 g of Ta2O5, 0.0087 g of Er2O3, and 0.0178 g of Yb2O3; wherein the molar ratio of each raw material is based on Na + Er 3+ Yb 3+ Ta 5+ =1.94:0.02:0.04:4.

[0033] S2: After mixing the raw materials, add ethanol to the mortar and grind for 30 minutes.

[0034] S3: After grinding, add Na2SO4 and K2SO4 powders in a molar ratio of 1:1 to the mixed raw materials. The molar ratio of Na2SO4 and K2SO4 to the reactants is 6:6:1. Then mix evenly.

[0035] S4: Place the raw materials into the muffle furnace at 1000°C. o After holding the crucible in C for 2 hours, immediately remove the crucible and cool it in an atmospheric environment.

[0036] S5: Soak the calcined material in deionized water, and remove Na2SO4 and K2SO4 by suction filtration to obtain Na2Ta4O. 11 :Er 3+ / Yb 3+ Single-phase material.

[0037] S6: Heat the above phosphor to 1000℃ and hold for 0h, then cool it with the furnace to obtain the corresponding material.

[0038] Example 3: The material preparation method in this embodiment includes the following steps: S1: Take 0.2327 g of raw materials NaCO3, 2 g of Ta2O5, 0.0087 g of Er2O3, and 0.0178 g of Yb2O3; wherein the molar ratio of each raw material is based on Na + Er 3+ Yb 3+ Ta 5+ =1.94:0.02:0.04:4.

[0039] S2: After mixing the raw materials, add ethanol to the mortar and grind for 30 minutes.

[0040] S3: After grinding, add Na2SO4 and K2SO4 powders in a molar ratio of 1:1 to the mixed raw materials. The molar ratio of Na2SO4 and K2SO4 to the reactants is 6:6:1. Then mix evenly.

[0041] S4: Place the raw materials into the muffle furnace at 1000°C. o After holding the crucible in C for 2 hours, immediately remove the crucible and cool it in an atmospheric environment.

[0042] S5: Soak the calcined material in deionized water, and remove Na2SO4 and K2SO4 by suction filtration to obtain Na2Ta4O. 11 :Er 3+ / Yb 3+ Single-phase material.

[0043] S6: Heat the above phosphor to 1100℃ and hold for 0h, then cool with the furnace to obtain the corresponding material.

[0044] Example 4: The material preparation method in this embodiment includes the following steps: S1: Take 0.2327 g of raw materials NaCO3, 2 g of Ta2O5, 0.0087 g of Er2O3, and 0.0178 g of Yb2O3; wherein the molar ratio of each raw material is based on Na + Er 3+ Yb 3+ Ta 5+ =1.94:0.02:0.04:4.

[0045] S2: After mixing the raw materials, add ethanol to the mortar and grind for 30 minutes.

[0046] S3: After grinding, add Na2SO4 and K2SO4 powders in a molar ratio of 1:1 to the mixed raw materials. The molar ratio of Na2SO4 and K2SO4 to the reactants is 6:6:1. Then mix evenly.

[0047] S4: Place the raw materials into the muffle furnace at 1000°C. o After holding the crucible in C for 2 hours, immediately remove the crucible and cool it in an atmospheric environment.

[0048] S5: Soak the calcined material in deionized water, and remove Na2SO4 and K2SO4 by suction filtration to obtain Na2Ta4O. 11 :Er 3+ / Yb 3+ Single-phase material.

[0049] S6: Heat the above phosphor to 1200℃ and hold for 0 hours, then cool it with the furnace to obtain the corresponding material.

[0050] Example 5: The material preparation method in this embodiment includes the following steps: S1: Take 0.2327 g of raw materials NaCO3, 2 g of Ta2O5, 0.0087 g of Er2O3, and 0.0178 g of Yb2O3; wherein the molar ratio of each raw material is based on Na + Er 3+ Yb 3+ Ta 5+ =1.94:0.02:0.04:4.

[0051] S2: After mixing the raw materials, add ethanol to the mortar and grind for 30 minutes.

[0052] S3: After grinding, add Na2SO4 and K2SO4 powders in a molar ratio of 1:1 to the mixed raw materials. The molar ratio of Na2SO4 and K2SO4 to the reactants is 6:6:1. Then mix evenly.

[0053] S4: Place the raw materials into the muffle furnace at 1000°C. o After holding the crucible in C for 2 hours, immediately remove the crucible and cool it in an atmospheric environment.

[0054] S5: Soak the calcined material in deionized water, and remove Na2SO4 and K2SO4 by suction filtration to obtain Na2Ta4O. 11 :Er 3+ / Yb 3+ Single-phase material.

[0055] S6: Heat the above phosphor to 1300℃ and hold for 0h, then cool with the furnace to obtain the corresponding material.

[0056] Example 6: The material preparation method in this embodiment includes the following steps: S1: Take 0.2327 g of raw materials NaCO3, 2 g of Ta2O5, 0.0087 g of Er2O3, and 0.0178 g of Yb2O3; wherein the molar ratio of each raw material is based on Na + Er 3+ Yb 3+ Ta 5+ =1.94:0.02:0.04:4.

[0057] S2: After mixing the raw materials, add ethanol to the mortar and grind for 30 minutes.

[0058] S3: After grinding, add Na2SO4 and K2SO4 powders in a molar ratio of 1:1 to the mixed raw materials. The molar ratio of Na2SO4 and K2SO4 to the reactants is 6:6:1. Then mix evenly.

[0059] S4: Place the raw materials into the muffle furnace at 1000°C. o After holding the crucible in C for 2 hours, immediately remove the crucible and cool it in an atmospheric environment.

[0060] S5: Soak the calcined material in deionized water, and remove Na2SO4 and K2SO4 by suction filtration to obtain Na2Ta4O. 11 :Er 3+ / Yb 3+ Single-phase material.

[0061] S6: Heat the above phosphor to 1400℃ and hold for 0h, then cool with the furnace to obtain the corresponding material.

[0062] Example 7: The material preparation method in this embodiment includes the following steps: S1: Take 0.2327 g of raw materials NaCO3, 2 g of Ta2O5, 0.0087 g of Er2O3, and 0.0178 g of Yb2O3; wherein the molar ratio of each raw material is based on Na + Er 3+ Yb 3+ Ta 5+ =1.94:0.02:0.04:4.

[0063] S2: After mixing the raw materials, add ethanol to the mortar and grind for 30 minutes.

[0064] S3: After grinding, add Na2SO4 and K2SO4 powders in a molar ratio of 1:1 to the mixed raw materials. The molar ratio of Na2SO4 and K2SO4 to the reactants is 6:6:1. Then mix evenly.

[0065] S4: Place the raw materials into the muffle furnace at 1000°C. o After holding the crucible in C for 2 hours, immediately remove the crucible and cool it in an atmospheric environment.

[0066] S5: Soak the calcined material in deionized water, and remove Na2SO4 and K2SO4 by suction filtration to obtain Na2Ta4O. 11 :Er 3+ / Yb 3+ Single-phase material.

[0067] S6: Heat the above phosphor to 1500℃ and hold for 0 hours, then cool it in the furnace to obtain the corresponding material.

[0068] Comparative Example 1: The only difference between this comparative example and Example 1 is that, in step S1, the molar ratio of each raw material in Comparative Example 1 is determined according to the chemical formula Na. a Er b Yb c Ta d O 11 Mix in the correct proportions, Na + Er 3+ Yb 3+ Ta 5+ =a:b:c:d to obtain Na + Er 3+ Yb 3+ Ta 5+ =1.94:0.02:0.04:8, where a+b+c=2; other steps are the same as in Example 1.

[0069] Comparative Example 2: This comparative example uses a high-temperature solid-state sintering method, and the specific steps are as follows: S1: Take 0.1163 g of raw materials NaCO3, 2 g of Ta2O5, 0.0043 g of Er2O3, and 0.0089 g of Yb2O3; wherein the molar ratio of each raw material is according to the chemical formula Na a Er b Yb c Ta8O 11 ; take Na + Er 3+ Yb 3+ Ta 5+ =1.94:0.02:0.04:8, where a+b+c=2.

[0070] S2: After mixing the raw materials, add alcohol to the mortar and grind for 30 minutes.

[0071] S3: After grinding, the sample is pressed into a sheet at 40 MPa, placed in a muffle furnace, and kept at 1000℃ for 30 min. The crucible is then immediately removed and cooled in an atmospheric environment.

[0072] S5: Crush the fired sample, press it into sheets again, and then... (The sentence is incomplete and requires more context to translate accurately.) o The material is obtained by holding it in temperature at room temperature for 2 hours and then cooling it in the furnace.

[0073] Structural performance testing 1. The structure of the upconversion fluorescent materials provided in Examples 1-7 and Comparative Examples 1-2 was analyzed, and the results are shown in the figure. Figure 1 and Figure 2 The test used a Cu target, and the equipment model was RigakuD / MAXRE, with an incident wavelength of λ = 1.5406 Å. Figure 1 In, through interaction with Na2Ta4O 11 and Na2Ta8O 21 A comparison with the standard PDF cards revealed that Example 1 is Na2Ta4O 11 :Er 3+ / Yb 3+ Single phase, with increasing heat treatment temperature, from Example 2 to Example 7, Na2Ta4O 11 The structure gradually shifts towards Na2Ta8O 21 Transformation, Example 7: Na2Ta8O 21 :Er 3+ / Yb 3+ Single-phase.

[0074] exist Figure 2 In, according to Na2Ta8O 21Comparative Example 1, synthesized using the molten salt method with Na₂SO₄ / K₂SO₄ as solvent, did not yield Na₂Ta₈O. 21 :Er 3+ / Yb 3+ The phosphor's material structure is still Na2Ta4O 11 Comparative Example 2, prepared by solid-state sintering, is Na₂Ta₄O. 11 It has a mixed structure with Ta2O5.

[0075] 2. SEM morphology inspection was performed on Examples 1 and 7 above. The inspection results are as follows: Figure 3 and Figure 4 As shown. XRD results indicate that Example 1 is a hexagonal phase Na₂Ta₄O₂. 11 :Er 3+ / Yb 3+ It has a hexagonal plate-like shape. Example 7, obtained after heat treatment, is a stacked structure.

[0076] 3. The fluorescence spectra of the upconversion phosphors provided in Examples 1-7 above under 980nm laser excitation were detected. Figure 5 It can be seen that as the heat treatment temperature increases, Na2Ta4O 11 :Er 3+ / Yb 3+ Gradually towards Na2Ta8O 21 :Er 3+ / Yb 3+ The upconversion fluorescence intensity gradually increases, while the spectral splitting gradually decreases. The integrated upconversion green fluorescence intensity of Example 7 is 16 times that of Example 1.

[0077] 4. Figure 6 These are the upconversion fluorescence spectra of Example 7 and Comparative Examples 1 and 2 under 980 nm laser excitation. The integrated intensity of the upconversion green fluorescence in Example 7 is 30 and 10 times that of Comparative Examples 1 and 2, respectively.

[0078] 5. A search of the XRD database revealed a TTB structure in Ba. 5.5 Ta 21.8 O 60 The standard XRD card matches Example 7 very well. Currently, due to the absence of Na2Ta8O... 21 The structure of the CIF file, this invention utilizes Ba 5.5 Ta 21.8 O 60 The cif file was used as the model, and the results are as follows: Figure 7 As shown, the parameters in the results are all within a reasonable range.

[0079] 6. The structural schematic diagram of Example 7 derived from the above-mentioned refinement results is as follows: Figure 8 As shown. In Figure 8 In the middle, by Er 3+ / Yb 3+ The distribution shows that a 3.90 Å distance along the c-axis provides 1D linear energy transfer, and 5 lattice sites in the ab plane achieve 2D in-plane energy transfer. Therefore, in Na₂Ta₈O₂… 21 In this context, energy transfer occurs locally through a combination of 1D linear and 2D in-plane energy transfer, where an Er 3+ There are a maximum of 6 Yb atoms around the ion. 3+ ion. Figure 9 a is Na2Ta4O 11 :Er 3+ / Yb 3+ Structural diagram, Er 3+ / Yb 3+ Replace Na + Grid position, Na + The ions are distributed in the 2D plane and isolated by a layer of Ta-O. Figure 9 b is Na + Schematic diagram of the 2D plane where Er is located 3+ and Yb 3+ The distance after doping is 3.59 Å. Energy transfer occurs in the 2D plane, and the energy transfer distance is consistently 3.59 Å. This single distance may be the cause of spectral splitting. Energy transfer is nonlocal; a single Er 3+ There are a maximum of 3 Yb atoms around the ion. 3+ Ions. This difference in energy transfer makes it possible to achieve the same Er... 3+ / Yb 3+ Under what doping concentration conditions, in Na2Ta8O 21 In the middle, Yb 3+ To Er 3+ The energy transfer efficiency is much higher than that of Na2Ta4O 11 Er 3+ and Yb 3+ .

[0080] In summary, existing technologies have achieved Na2Ta8O 21 Er doping 3+ Yb 3+ fluorescent powder, Er 3+ and Yb 3 Replace Na + The lattice sites. The Na₂SO₄ / K₂SO₄ molten salt method combined with heat treatment can successfully obtain Na₂Ta₈O with a TTB structure. 21 :Er 3+ / Yb 3+A phosphor, possessing properties such as single-phase composition and high fluorescence intensity, was also described. Na₂Ta₈O₃ was also specified. 21 :Er 3+ / Yb 3+ The structure and atomic occupancy.

[0081] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. An erbium-ytterbium-doped Na₂Ta₈O 21 A method for preparing upconversion phosphor, characterized in that, Includes the following steps: S1, according to the chemical formula Na a Er b Yb c Ta4O 11 ZhongNa + Er 3+ Yb 3+ Ta 5+ The molar ratio of sodium source, tantalum source, erbium source and ytterbium source is weighed and mixed to obtain mixed raw material A; where a+b+c=2. S2. Place the mixed raw material A into a mortar and add wet grinding media for grinding. Then add Na2SO4 and K2SO4 in a molar ratio of 1:1 and mix to obtain mixed raw material B. S3. The mixed raw material B is calcined at 1000°C for 2 hours. After cooling, the calcined material is soaked in deionized water, and the Na2SO4 and K2SO4 are removed by filtration to obtain Na2Ta4O. 11 :Er 3+ / Yb 3+ Single-phase materials; S4, the Na2Ta4O 11 :Er 3+ / Yb 3+ Single-phase material was heat-treated at 1500℃ to obtain Na₂Ta₈O. 21 :Er 3+ / Yb 3+ Single-phase material.

2. The preparation method according to claim 1, characterized in that, In step S1, Na + Er 3+ Yb 3+ Ta 5+ The molar ratio is 1.94:0.02:0.04:

4.

3. The preparation method according to claim 1, characterized in that, In step S1, the sodium source is NaCO3; the tantalum source is Ta2O5; the erbium source is Er2O3; the ytterbium source is Yb2O3; and the purity of NaCO3, Er2O3, Yb2O3, and Ta2O5 is 99.0-99.9%.

4. The preparation method according to claim 1, characterized in that, In step S2, the grinding time is 30 min; the molar ratio of Na2SO4, K2SO4 and the mixed raw materials is 6:6:1; and the wet grinding medium is ethanol.

5. The preparation method according to claim 1, characterized in that, In step S3, the Na2Ta4O 11 :Er 3+ / Yb 3+ Single-phase materials have a hexagonal phase structure.

6. The preparation method according to claim 1, characterized in that, In step S4, the erbium-ytterbium doped Na₂Ta₈O 21 The upconversion phosphor has a tetragonal tungsten bronze phase structure.

7. Erbium-ytterbium-doped Na₂Ta₈O prepared by the preparation method according to any one of claims 1-6 21 Upconversion phosphor, characterized in that, The erbium-ytterbium-doped Na₂Ta₈O 21 upconversion phosphor with Na2Ta8O 21 The matrix is ​​doped with Er. 3+ and Yb 3+ ; The erbium-ytterbium-doped Na₂Ta₈O 21 The general chemical formula of upconversion phosphor is Na a Er b Yb c Ta8O 21 , where a+b+c=2.

8. The erbium-ytterbium-doped Na₂Ta₈O according to claim 7 21 Upconversion phosphor, characterized in that, The erbium-ytterbium-doped Na₂Ta₈O 21 The general chemical formula of upconversion phosphor is Na a Er b Yb c Ta8O 21 , where a=1.94, b=0.02, c=0.

04.

9. The erbium-ytterbium-doped Na₂Ta₈O according to claim 7 21 Upconversion phosphor, characterized in that, The erbium-ytterbium-doped Na₂Ta₈O 21 The upconversion phosphor has a tetragonal tungsten bronze phase structure.

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