α-U3O8 layered tantalate upconversion luminescent material and preparation method thereof

Abstract

The present invention discloses an α-U3O8 layered tantalate upconversion luminescent material and a preparation method thereof. The preparation method of the α-U3O8 layered tantalate upconversion luminescent material comprises the following steps: S1: weighing raw material one, Er2O3, Yb2O3 and Ta2O5, mixing and grinding, wherein the raw material one is an oxide or salt of A, and A is Sr, Ca, Na, Bi, La, Eu, Gd or Y; S2: mixing the raw material mixture obtained in step S1 with 1 to 10 times the weight of B2O3, sintering at 900°C to 1200°C for 4h to 24h; S3: adding water to the material sintered in step S2, filtering it with suction, and drying it for 2h to 24h to obtain Er2O3. 3+ and Yb 3+ Co-doped α-U3O8 layered tantalate upconversion luminescent material. The green fluorescence intensity of the α-U3O8 layered tantalate upconversion luminescent material described in the present invention is comparable to that of NaYF4:Er 3+ / Yb 3+ Upconversion phosphors are expected to replace NaYF4:Er in acid-base environments, high-temperature environments, biomedicine, and temperature sensing. 3+ / Yb 3+ Upconversion phosphors.

Description

Technical Field

[0001] The present invention relates to the technical field of up-conversion luminescent materials, and in particular to an α-U3O8 layered tantalate up-conversion luminescent material and a preparation method thereof. Background Art

[0002] Currently, NaYF4:Er 3+ / Yb 3+ Due to its outstanding fluorescence intensity, upconversion phosphors are widely used in biomedicine, solar cells, photocatalysis, non-contact temperature testing, anti-counterfeiting and plant growth. However, the poor chemical stability and certain toxicity of fluoride have limited the application of NaYF4:Er 3+ / Yb 3+ Using chemically stable oxides to replace fluorides is a new topic for expanding applications. Summary of the Invention

[0003] In response to the above problems, the present invention studies and designs an α-U3O8 layered tantalate upconversion luminescent material and its preparation method. The technical means adopted by the present invention are as follows:

[0004] A method for preparing an α-U3O8 layered tantalate upconversion luminescent material comprises the following steps:

[0005] S1: Weigh raw material 1, Er2O3, Yb2O3 and Ta2O5, mix and grind, wherein raw material 1 is an oxide or salt of A, and A is Sr, Ca, Na, Bi, La, Eu, Gd or Y;

[0006] S2: mixing the raw material mixture obtained in step S1 with 1 to 10 times the weight of B2O3, and sintering at 900-1200°C for 4-24 hours;

[0007] S3: After adding water to the material sintered in step S2 and filtering it, dry it for 2h-24h to obtain Er 3+ and Yb 3+ Co-doped α-U3O8 layered tantalate upconversion luminescent materials.

[0008] Further, in step S1, according to A:Er 3+ :Yb 3+ :Ta 5+ =a:b:c:d molar ratio: weigh raw materials 1, Er2O3, Yb2O3 and Ta2O5, wherein a+b+c=1 or 2, d=4 or 7, and the specific values ​​are selected according to the valence balance.

[0009] Furthermore, in step S1, a=0.94, b=0.02, c=0.04, and d=4.

[0010] Furthermore, in step S1, A is Y, La or Bi, a=0.5, b=0.1, c=0.4, and d=7.

[0011] Furthermore, the first raw material is CaCO3, NaCl, Eu2O3, Gd2O3, Sr(NO3)2, SrCO3, Bi2O3, La2O3 or Y2O3.

[0012] Furthermore, in step S1, the grinding time is 30 minutes, and in step S3, the drying temperature is 80°C.

[0013] Furthermore, the purity of the Sr salts Er2O3, Yb2O3 and Ta2O5 is not less than 99.9%.

[0014] An α-U3O8 layered tantalate up-conversion luminescent material is prepared by the preparation method of the α-U3O8 layered tantalate up-conversion luminescent material of the present invention, with α-U3O8 layered tantalate as a matrix, and the matrix is ​​doped with Er 3+ and Yb 3+ The chemical formula of the α-U3O8 layered tantalate is A x Ta 3n+1 O 8n+3 , wherein x=1 or 2, n=1 or 2, and A is Sr, Ca, Na, Bi, La, Eu, Gd, or Y. When A has a valence of +2 in the α-U3O8 layered tantalate, then x=1 and n=1; when A has a valence of +1 in the α-U3O8 layered tantalate, then x=2 and n=1; when A has a valence of +3 in the α-U3O8 layered tantalate, then x=1 and n=2.

[0015] Furthermore, the chemical formula of the α-U3O8 layered tantalate upconversion luminescent material is A x Ta 3n+1 O 8n+3 :b Er 3 + / c Yb 3+ , where 0<b≤0.2, 0<c≤0.5.

[0016] Furthermore, the chemical formula of the α-U3O8 layered tantalate upconversion luminescent material is SrTa4O 11 :0.02Er 3+ / 0.04Yb 3+ 、YTa7O 19 :0.1Er 3+ / 0.4Yb 3+ 、LaTa7O 19 :0.1Er 3+ / 0.4Yb 3+or BiTa7O 19 :0.1Er 3+ / 0.4Yb 3+ .

[0017] Compared with the prior art, the green fluorescence intensity of the α-U3O8 layered tantalate upconversion luminescent material of the present invention is comparable to that of NaYF4:Er 3+ / Yb 3+ Upconversion phosphors. Especially BiTa7O prepared using B2O3 as solvent 19 :0.1Er 3+ / 0.4Yb 3+ The green upconversion fluorescence intensity of the sample is NaYF4:Er 3+ / Yb 3+ The present invention is expected to replace NaYF4:Er in the fields of acid-base environment, high temperature environment, biomedicine and temperature sensing. 3+ / Yb 3+ Upconversion phosphors. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is SrTa4O 11 :0.02Er 3+ / 0.04Yb 3+ XRD results of samples prepared by molten salt, atmospheric solid phase sintering and vacuum solid phase sintering at different temperatures using KCl solvent.

[0019] Figure 2 SrTa4O was prepared by molten salt method using B2O3 solvent at 750℃ with different holding time. 11 :0.02Er 3 + / 0.04Yb 3+ XRD results of the sample.

[0020] Figure 3 SrTa4O was prepared by molten salt method using B2O3 solvent at 800℃ with different holding time. 11 :0.02Er 3 + / 0.04Yb 3+ XRD results of the sample.

[0021] Figure 4 SrTa4O prepared by molten salt method using B2O3 solvent at 900℃ with different holding times 11 :0.02Er 3+ / 0.04Yb 3+ XRD results of the sample.

[0022] Figure 5 SrTa4O was prepared by molten salt method using B2O3 solvent at different temperatures for 24h. 11 :0.02Er 3+ / 0.04Yb 3+ XRD results of the sample.

[0023] Figure 6 BiTa7O was prepared by molten salt method using B2O3 as solvent. 19 :0.1Er 3+ / 0.4Yb 3+ ,LaTa7O 19 :0.1Er 3+ / 0.4Yb 3+ and YTa7O 19 :0.1Er 3+ / 0.4Yb 3+ XRD results of the sample.

[0024] Figure 7 SrTa4O was prepared by molten salt method with B2O3 as solvent under 980nm laser excitation. 11 :0.02Er 3+ / 0.04Yb 3+ , YTa7O 19 :0.1Er 3+ / 0.4Yb 3+ ,LaTa7O 19 :0.1Er 3+ / 0.4Yb 3+ ,BiTa7O 19 :0.1Er 3+ / 0.4Yb 3+ Samples and NaYF4:Er 3+ / Yb 3+ Upconversion spectrum of .

[0025] Figure 8 SrTa4O prepared by molten salt method with B2O3 as solvent under 980nm laser excitation 11 :0.02Er 3+ / 0.04Yb 3 + Temperature spectrum of .

[0026] Figure 9 It is SrTa4O 11 :0.02Er 3+ / 0.04Yb 3+ The relationship between the fluorescence branching ratio LIR value and temperature.

[0027] Figure 10 It is SrTa4O11 :0.02Er 3+ / 0.04Yb 3+ A plot of the relationship between relative temperature sensitivity and temperature. DETAILED DESCRIPTION

[0028] The applicant is studying layered BiTa7O 19 :Er 3+ / Yb 3+ Phosphor was found to be 3+ / Yb 3+ If distributed in a single layer, and Er 3+ / Yb 3+ If the distribution layer is isolated by other atoms, significant green upconversion fluorescence will be obtained. The chemical formula of α-U3O8 layered tantalate is A x Ta 3n+1 O 8n+3 ,x=1,2;n=1,2. The applicant found that some α-U3O8 layered tantalate structures can be successfully prepared by traditional solid phase sintering, such as BiTa7O 19 , LaTa7O 19 However, some structures are very difficult to obtain or even impossible to obtain, such as CaTa4O 11 , SrTa4O 11 Finding a simple synthesis method that can successfully produce the entire system is a challenge. Based on these issues, the applicant discovered that using B2O3 as a solvent is superior to solvents such as KCl and NaCl and can be used to prepare the entire system. Furthermore, compared to traditional solid-phase sintering methods, the molten salt method allows for precise control of crystal growth by adjusting the reaction temperature, holding time, and the ratio of solvent to raw materials.

[0029] Example 1 (Sr a Er b Yb c )Ta4O 11 :A binary erbium-ytterbium-doped SrTa4O 11 The invention relates to a method for preparing a green up-conversion luminescent material, adopting a molten salt method.

[0030] The main steps are as follows:

[0031] S1: Take Sr(NO3)2, Er2O3, Yb2O3, Ta2O5 as raw materials; according to Sr 2+ :Er 3+ :Yb 3+ :Ta 5+= 0.94:0.02:0.04:4 molar ratio, take 0.4502g Sr(NO3)2, 0.0087g Er2O3, 0.0178g Yb2O3 and 2g Ta2O5, mix them in a mortar and grind them for 30 minutes;

[0032] S2: Add 20 g of KCl to the raw materials and sinter at 800 °C for 2 h in a resistance furnace.

[0033] S3: The sintered sample is filtered and then placed in an oven for drying at 80°C for 2 hours to obtain an upconversion luminescent material.

[0034] Example 2 (Sr a Er b Yb c )Ta4O 11 :A binary erbium-ytterbium-doped SrTa4O 11 The invention relates to a method for preparing a green up-conversion luminescent material, adopting a molten salt method.

[0035] The main steps are as follows:

[0036] S1: Take Sr(NO3)2, Er2O3, Yb2O3, Ta2O5 as raw materials; according to Sr 2+ :Er 3+ :Yb 3+ :Ta 5+ = 0.94:0.02:0.04:4 molar ratio, take 0.4502g Sr(NO3)2, 0.0087g Er2O3, 0.0178g Yb2O3 and 2g Ta2O5, mix them in a mortar and grind them for 30 minutes;

[0037] S2: Add 20 g of KCl to the raw materials and sinter at 850 °C for 2 h in a resistance furnace.

[0038] S3: The sintered sample is filtered and then placed in an oven for drying at 80°C for 2 hours to obtain an upconversion luminescent material.

[0039] Example 3 (Sr a Er b Yb c )Ta4O 11 :A binary erbium-ytterbium-doped SrTa4O 11 The invention relates to a method for preparing a green up-conversion luminescent material, adopting a molten salt method.

[0040] The main steps are as follows:

[0041] S1: Take Sr(NO3)2, Er2O3, Yb2O3, Ta2O5 as raw materials; according to Sr 2+ :Er3+ :Yb 3+ :Ta 5+ = 0.94:0.02:0.04:4 molar ratio, take 0.4502g Sr(NO3)2, 0.0087g Er2O3, 0.0178g Yb2O3 and 2g Ta2O5, mix them in a mortar and grind them for 30 minutes;

[0042] S2: Add 20 g of KCl to the raw materials and sinter at 950 °C for 2 h in a resistance furnace.

[0043] S3: The sintered sample is filtered and then placed in an oven for drying at 80°C for 2 hours to obtain an upconversion luminescent material.

[0044] Example 4 (Sr a Er b Yb c )Ta4O 11 :A binary erbium-ytterbium-doped SrTa4O 11 The invention relates to a method for preparing a green up-conversion luminescent material, adopting a molten salt method.

[0045] The main steps are as follows:

[0046] S1: Take Sr(NO3)2, Er2O3, Yb2O3, Ta2O5 as raw materials; according to Sr 2+ :Er 3+ :Yb 3+ :Ta 5+ = 0.94:0.02:0.04:4 molar ratio, take 0.4502g Sr(NO3)2, 0.0087g Er2O3, 0.0178g Yb2O3 and 2g Ta2O5, mix them in a mortar and grind them for 30 minutes;

[0047] S2: Add 20 g of KCl to the raw materials and sinter at 1050 °C for 2 h in a resistance furnace.

[0048] S3: The sintered sample is filtered and then placed in an oven for drying at 80°C for 2 hours to obtain an upconversion luminescent material.

[0049] Example 5 (Sr a Er b Yb c )Ta4O 11 :A binary erbium-ytterbium-doped SrTa4O 11 The invention relates to a method for preparing a green up-conversion luminescent material, adopting a molten salt method.

[0050] The main steps are as follows:

[0051] S1: Take Sr(NO3)2, Er2O3, Yb2O3, Ta2O5 as raw materials; according to Sr 2+ :Er 3+ :Yb 3+ :Ta 5+ = 0.94:0.02:0.04:4 molar ratio, take 0.4502g Sr(NO3)2, 0.0087g Er2O3, 0.0178g Yb2O3 and 2g Ta2O5, mix them in a mortar and grind them for 30 minutes;

[0052] S2: Add 20 g of KCl to the raw materials and sinter at 1250 °C for 2 h in a resistance furnace.

[0053] S3: The sintered sample is filtered and then placed in an oven for drying at 80°C for 2 hours to obtain an upconversion luminescent material.

[0054] Example 6 (Sr a Er b Yb c )Ta4O 11 :A binary erbium-ytterbium-doped SrTa4O 11 The invention relates to a method for preparing a green up-conversion luminescent material, adopting a solid-phase method.

[0055] The main steps are as follows:

[0056] S1: Take Sr(NO3)2, Er2O3, Yb2O3, Ta2O5 as raw materials; according to Sr 2+ :Er 3+ :Yb 3+ :Ta 5+ =0.94:0.02:0.04:4 molar ratio, take 0.4502g Sr(NO3)2, 0.0087g Er2O3, 0.0178g Yb2O3 and 2g Ta2O5;

[0057] S2: First, mix Sr(NO3)2 and Ta2O5 in a mortar and grind them for 30 minutes, sinter them at 600℃ in a resistance furnace for 24 hours, and then sinter them at 800℃ for 24 hours. After taking them out, mix them with Er2O3 and Yb2O3 and grind them for 30 minutes. Finally, sinter them at 1027℃ in a resistance furnace for 24 hours.

[0058] S3: Grind the sintered sample to obtain an upconversion luminescent material.

[0059] Example 7 (Sr a Er b Yb c )Ta4O 11 :A binary erbium-ytterbium-doped SrTa4O11 The invention relates to a method for preparing a green up-conversion luminescent material, which adopts a vacuum solid-phase method.

[0060] The main steps are as follows:

[0061] S1: Take Sr(NO3)2, Er2O3, Yb2O3, Ta2O5 as raw materials; according to Sr 2+ :Er 3+ :Yb 3+ :Ta 5+ =0.94:0.02:0.04:4 molar ratio, take 0.4502g Sr(NO3)2, 0.0087g Er2O3, 0.0178g Yb2O3 and 2g Ta2O5;

[0062] S2: First, mix Sr(NO3)2 and Ta2O5 in a mortar and grind them for 30 minutes, sinter them at 600℃ in a resistance furnace for 24 hours, and then sinter them at 800℃ for 24 hours. After taking them out, mix them with Er2O3 and Yb2O3 and grind them for 30 minutes. Place the evenly mixed raw materials in a test tube, seal the tube and draw a vacuum, and finally sinter them at 1027℃ in a resistance furnace for 24 hours.

[0063] S3: Grind the sintered sample to obtain an upconversion luminescent material.

[0064] Example 8 (Sr a Er b Yb c )Ta4O 11 :A binary erbium-ytterbium-doped SrTa4O 11 The invention relates to a method for preparing a green up-conversion luminescent material, adopting a molten salt method.

[0065] The main steps are as follows:

[0066] S1: Take Sr(NO3)2, Er2O3, Yb2O3, Ta2O5 as raw materials; according to Sr 2+ :Er 3+ :Yb 3+ :Ta 5+ = 0.94:0.02:0.04:4 molar ratio, take 0.4502g Sr(NO3)2, 0.0087g Er2O3, 0.0178g Yb2O3 and 2g Ta2O5, mix them in a mortar and grind them for 30 minutes;

[0067] S2: Add 15g B2O3 to the raw materials and calcine at 750℃ in a resistance furnace for 4h.

[0068] S3: The sintered sample is filtered and then placed in an oven for drying at 80°C for 2 hours to obtain an upconversion luminescent material.

[0069] Example 9 (Sr a Er b Yb c )Ta4O 11 :A binary erbium-ytterbium-doped SrTa4O 11 The invention relates to a method for preparing a green up-conversion luminescent material, adopting a molten salt method.

[0070] The main steps are as follows:

[0071] S1: Take Sr(NO3)2, Er2O3, Yb2O3, Ta2O5 as raw materials; according to Sr 2+ :Er 3+ :Yb 3+ :Ta 5+ = 0.94:0.02:0.04:4 molar ratio, take 0.4502g Sr(NO3)2, 0.0087g Er2O3, 0.0178g Yb2O3 and 2g Ta2O5, mix them in a mortar and grind them for 30 minutes;

[0072] S2: Add 15g B2O3 to the raw materials and mix them, and calcine them at 750℃ in a resistance furnace for 12h.

[0073] S3: The sintered sample is filtered and then placed in an oven for drying at 80°C for 2 hours to obtain an upconversion luminescent material.

[0074] Example 10 (Sr a Er b Yb c )Ta4O 11 :A binary erbium-ytterbium-doped SrTa4O 11 The invention relates to a method for preparing a green up-conversion luminescent material, adopting a molten salt method.

[0075] The main steps are as follows:

[0076] S1: Take Sr(NO3)2, Er2O3, Yb2O3, Ta2O5 as raw materials; according to Sr 2+ :Er 3+ :Yb 3+ :Ta 5+ = 0.94:0.02:0.04:4 molar ratio, take 0.4502g Sr(NO3)2, 0.0087g Er2O3, 0.0178g Yb2O3 and 2g Ta2O5, mix them in a mortar and grind them for 30 minutes;

[0077] S2: Add 15g B2O3 to the raw materials and mix them, and calcine them at 750℃ in a resistance furnace for 24h.

[0078] S3: The sintered sample is filtered and then placed in an oven for drying at 80°C for 2 hours to obtain an upconversion luminescent material.

[0079] Example 11 (Sr a Er b Yb c )Ta4O 11 :A binary erbium-ytterbium-doped SrTa4O 11 The invention relates to a method for preparing a green up-conversion luminescent material, adopting a molten salt method.

[0080] The main steps are as follows:

[0081] S1: Take Sr(NO3)2, Er2O3, Yb2O3, Ta2O5 as raw materials; according to Sr 2+ :Er 3+ :Yb 3+ :Ta 5+ = 0.94:0.02:0.04:4 molar ratio, take 0.4502g Sr(NO3)2, 0.0087g Er2O3, 0.0178g Yb2O3 and 2g Ta2O5, mix them in a mortar and grind them for 30 minutes;

[0082] S2: Add 15g B2O3 to the raw materials and calcine at 800℃ in a resistance furnace for 4h.

[0083] S3: The sintered sample is filtered and then placed in an oven for drying at 80°C for 2 hours to obtain an upconversion luminescent material.

[0084] Example 12 (Sr a Er b Yb c )Ta4O 11 :A binary erbium-ytterbium-doped SrTa4O 11 The invention relates to a method for preparing a green up-conversion luminescent material, adopting a molten salt method.

[0085] The main steps are as follows:

[0086] S1: Take Sr(NO3)2, Er2O3, Yb2O3, Ta2O5 as raw materials; according to Sr 2+ :Er 3+ :Yb 3+ :Ta 5+ = 0.94:0.02:0.04:4 molar ratio, take 0.4502g Sr(NO3)2, 0.0087g Er2O3, 0.0178g Yb2O3 and 2g Ta2O5, mix them in a mortar and grind them for 30 minutes;

[0087] S2: Add 15g B2O3 to the raw materials and mix them, and calcine them at 800℃ in a resistance furnace for 12h.

[0088] S3: The sintered sample is filtered and then placed in an oven for drying at 80°C for 2 hours to obtain an upconversion luminescent material.

[0089] Example 13 (Sr a Er b Yb c )Ta4O 11 :A binary erbium-ytterbium-doped SrTa4O 11 The invention relates to a method for preparing a green up-conversion luminescent material, adopting a molten salt method.

[0090] The main steps are as follows:

[0091] S1: Take Sr(NO3)2, Er2O3, Yb2O3, Ta2O5 as raw materials; according to Sr 2+ :Er 3+ :Yb 3+ :Ta 5+ = 0.94:0.02:0.04:4 molar ratio, take 0.4502g Sr(NO3)2, 0.0087g Er2O3, 0.0178g Yb2O3 and 2g Ta2O5, mix them in a mortar and grind them for 30 minutes;

[0092] S2: Add 15g B2O3 to the raw materials and calcine at 800℃ in a resistance furnace for 24h.

[0093] S3: The sintered sample is filtered and then placed in an oven for drying at 80°C for 2 hours to obtain an upconversion luminescent material.

[0094] Example 14 (Sr a Er b Yb c )Ta4O 11 :A binary erbium-ytterbium-doped SrTa4O 11 The invention relates to a method for preparing a green up-conversion luminescent material, adopting a molten salt method.

[0095] The main steps are as follows:

[0096] S1: Take Sr(NO3)2, Er2O3, Yb2O3, Ta2O5 as raw materials; according to Sr 2+ :Er 3+ :Yb 3+ :Ta 5+= 0.94:0.02:0.04:4 molar ratio, take 0.4502g Sr(NO3)2, 0.0087g Er2O3, 0.0178g Yb2O3 and 2g Ta2O5, mix them in a mortar and grind them for 30 minutes;

[0097] S2: Add 15g B2O3 to the raw materials and calcine at 900℃ in a resistance furnace for 4h.

[0098] S3: The sintered sample is filtered and then placed in an oven for drying at 80°C for 2 hours to obtain an upconversion luminescent material.

[0099] Example 15 (Sr a Er b Yb c )Ta4O 11 :A binary erbium-ytterbium-doped SrTa4O 11 The invention relates to a method for preparing a green up-conversion luminescent material, adopting a molten salt method.

[0100] The main steps are as follows:

[0101] S1: Take Sr(NO3)2, Er2O3, Yb2O3, Ta2O5 as raw materials; according to Sr 2+ :Er 3+ :Yb 3+ :Ta 5+ = 0.94:0.02:0.04:4 molar ratio, take 0.4502g Sr(NO3)2, 0.0087g Er2O3, 0.0178g Yb2O3 and 2g Ta2O5, mix them in a mortar and grind them for 30 minutes;

[0102] S2: Add 15g B2O3 to the raw materials and mix them, and calcine them at 900℃ in a resistance furnace for 12h.

[0103] S3: The sintered sample is filtered and then placed in an oven for drying at 80°C for 2 hours to obtain an upconversion luminescent material.

[0104] Example 16 (Sr a Er b Yb c )Ta4O 11 :A binary erbium-ytterbium-doped SrTa4O 11 The invention relates to a method for preparing a green up-conversion luminescent material, adopting a molten salt method.

[0105] The main steps are as follows:

[0106] S1: Take Sr(NO3)2, Er2O3, Yb2O3, Ta2O5 as raw materials; according to Sr 2+ :Er3+ :Yb 3+ :Ta 5+ = 0.94:0.02:0.04:4 molar ratio, take 0.4502g Sr(NO3)2, 0.0087g Er2O3, 0.0178g Yb2O3 and 2g Ta2O5, mix them in a mortar and grind them for 30 minutes;

[0107] S2: Add 15g B2O3 to the raw materials and calcine at 900℃ in a resistance furnace for 24h.

[0108] S3: The sintered sample is filtered and then placed in an oven for drying at 80°C for 2 hours to obtain an upconversion luminescent material.

[0109] Example 17 (Sr a Er b Yb c )Ta4O 11 :A binary erbium-ytterbium-doped SrTa4O 11 The invention relates to a method for preparing a green up-conversion luminescent material, adopting a molten salt method.

[0110] The main steps are as follows:

[0111] S1: Take Sr(NO3)2, Er2O3, Yb2O3, Ta2O5 as raw materials; according to Sr 2+ :Er 3+ :Yb 3+ :Ta 5+ = 0.94:0.02:0.04:4 molar ratio, take 0.4502g Sr(NO3)2, 0.0087g Er2O3, 0.0178g Yb2O3 and 2g Ta2O5, mix them in a mortar and grind them for 30 minutes;

[0112] S2: Add 15g B2O3 to the raw materials and mix them, and calcine them at 1000℃ in a resistance furnace for 24h.

[0113] S3: The sintered sample is filtered and then placed in an oven for drying at 80°C for 2 hours to obtain an upconversion luminescent material.

[0114] Example 18 (Sr a Er b Yb c )Ta4O 11 :A binary erbium-ytterbium-doped SrTa4O 11 The invention relates to a method for preparing a green up-conversion luminescent material, adopting a molten salt method.

[0115] The main steps are as follows:

[0116] S1: Take Sr(NO3)2, Er2O3, Yb2O3, Ta2O5 as raw materials; according to Sr 2+ :Er 3+ :Yb 3+ :Ta 5+ = 0.94:0.02:0.04:4 molar ratio, take 0.4502g Sr(NO3)2, 0.0087g Er2O3, 0.0178g Yb2O3 and 2g Ta2O5, mix them in a mortar and grind them for 30 minutes;

[0117] S2: Add 15g B2O3 to the raw materials and mix them, and calcine them at 1100℃ in a resistance furnace for 24h.

[0118] S3: The sintered sample is filtered and then placed in an oven for drying at 80°C for 2 hours to obtain an upconversion luminescent material.

[0119] Example 19 (Bi a Er b Yb c )Ta7O 19 :A binary Er-Yb doped BiTa7O 19 The invention relates to a method for preparing a green up-conversion luminescent material, adopting a molten salt method.

[0120] The main steps are as follows:

[0121] S1: Take Bi2O3, Er2O3, Yb2O3, Ta2O5 as raw materials; according to Bi 3+ :Er 3+ :Yb 3+ :Ta 5+ = 0.5:0.1:0.4:7 molar ratio, take 0.1506g Bi2O3, 0.0247g Er2O3, 0.1019g Yb2O3 and 2g Ta2O5, mix them in a mortar and grind for 30 minutes;

[0122] S2: Add 15g B2O3 to the raw materials and mix them, and calcine them at 1000℃ in a resistance furnace for 4h.

[0123] S3: The sintered sample is filtered and then placed in an oven for drying at 80°C for 2 hours to obtain an upconversion luminescent material.

[0124] Example 20 (La a Er b Yb c )Ta7O 19 :A binary Er-Yb doped LaTa7O 19 The invention relates to a method for preparing a green up-conversion luminescent material, adopting a molten salt method.

[0125] The main steps are as follows:

[0126] S1: Take La2O3, Er2O3, Yb2O3, Ta2O5 as raw materials; according to La 3+ :Er 3+ :Yb 3+ :Ta 5+ = 0.5:0.1:0.4:7 molar ratio, take 0.1053g La2O3, 0.0247g Er2O3, 0.1019g Yb2O3 and 2g Ta2O5, mix them in a mortar and grind for 30 minutes;

[0127] S2: Add 15g B2O3 to the raw materials and mix them, and calcine them at 1000℃ in a resistance furnace for 4h.

[0128] S3: The sintered sample is filtered and then placed in an oven for drying at 80°C for 2 hours to obtain an upconversion luminescent material.

[0129] Example 21 (Y a Er b Yb c )Ta7O 19 :A binary Er-Yb-doped YTa7O 19 The invention relates to a method for preparing a green up-conversion luminescent material, adopting a molten salt method.

[0130] The main steps are as follows:

[0131] S1: Take Y2O3, Er2O3, Yb2O3, Ta2O5 as raw materials; according to La 3+ :Er 3+ :Yb 3+ :Ta 5+ = 0.5:0.1:0.4:7 molar ratio, take 0.0730g Y2O3, 0.0247g Er2O3, 0.1019g Yb2O3 and 2g Ta2O5, mix them in a mortar and grind for 30 minutes;

[0132] S2: Add 15g B2O3 to the raw materials and mix them, and calcine them at 1000℃ in a resistance furnace for 4h.

[0133] S3: The sintered sample is filtered and then placed in an oven for drying at 80°C for 2 hours to obtain an upconversion luminescent material.

[0134] Comparative Example:

[0135] The existing commercial NaYF4:Er 3+ / Yb 3+ The green phosphor was tested and compared with the fluorescence performance of the samples prepared in the examples. Figure 7 .

[0136] Figure 1 These are XRD results of samples prepared by molten salt in KCl solvent at different temperatures, solid-phase sintering in atmosphere, and solid-phase sintering in vacuum in Examples 1-7.

[0137] Figure 1 The results show that the SrTa4O prepared by the molten salt method using KCl as solvent 11 :0.02Er 3+ / 0.04Yb 3+ The sample is mainly tetragonal phase between 800℃-1250℃, and a small amount of hexagonal phase appears as the temperature decreases. 11 It does not belong to the α-U3O8 structure, and the hexagonal crystal belongs to the α-U3O8 structure. The sample prepared by the atmospheric solid phase sintering method is a mixed structure of tetragonal and hexagonal crystals, and the vacuum solid phase sintering method can obtain the hexagonal crystal. Here, it shows that KCl as a solvent cannot synthesize the hexagonal SrTa4O 11 :Er 3+ / Yb 3+ Phosphor.

[0138] Figure 2 The SrTa4O prepared by the molten salt method at 750℃ with different holding times in the B2O3 solvent of Examples 8-10 11 :0.02Er 3+ / 0.04Yb 3+ XRD results of the sample.

[0139] Figure 2 It shows that at 750℃, as the holding time increases from 4h to 12h, a layered β-Ta2O5 structure is formed first, and then when the holding time increases to 24h, a large amount of hexagonal SrTa4O 11 However, there are still a lot of β-Ta2O5 impurity phases.

[0140] Figure 3 The SrTa4O prepared by the molten salt method at 800℃ with different holding times using the B2O3 solvent of Examples 11-13 11 :0.02Er 3+ / 0.04Yb 3+ XRD results of the sample.

[0141] On the basis of 750℃, the reaction temperature is further increased to 800℃. With the increase of reaction time, the impurity phase β-Ta2O5 gradually disappears. When the reaction time reaches 24h, it is almost hexagonal SrTa4O 11 :0.02Er 3+ / 0.04Yb 3+Pure phase.

[0142] Figure 4 The SrTa4O prepared by the molten salt method at 900℃ with different holding times using the B2O3 solvent of Examples 14-16 11 :0.02Er 3+ / 0.04Yb 3+ XRD results of the sample.

[0143] On the basis of 800℃, the reaction temperature was further increased to 900℃ and the reaction time was increased from 4h to 24h. All samples were almost hexagonal SrTa4O 11 :0.02Er 3+ / 0.04Yb 3+ Pure phase.

[0144] Figure 5 The SrTa4O prepared by the molten salt method using the B2O3 solvent of Examples 10, 13, 16-18 at different temperatures for 24 hours 11 :0.02Er 3+ / 0.04Yb 3+ XRD results of the sample.

[0145] Figure 5 It shows that the holding time is unchanged at 24h. On the basis of 900℃, the reaction temperature is further increased. When the temperature is higher than 900℃, the hexagonal SrTa4O 11 It will gradually transform into β-Ta2O5. At 1100℃ and 24h, the sample structure is consistent with β-Ta2O5.

[0146] Figure 6 BiTa7O prepared by the molten salt method using B2O3 as the solvent in Examples 19-21 19 :0.1Er 3+ / 0.4Yb 3+ ,LaTa7O 19 :0.1Er 3+ / 0.4Yb 3+ and YTa7O 19 :0.1Er 3+ / 0.4Yb 3+ XRD results of the sample.

[0147] Figure 6 It shows that B2O3 can not only be used to synthesize SrTa4O in molten salt 11 , BiTa7O with α-U3O8 structure can also be synthesized 19 :0.1Er 3+ / 0.4Yb 3+ ,LaTa7O 19:0.1Er 3+ / 0.4Yb 3+ and YTa7O 19 :0.1Er 3+ / 0.4Yb 3+ Therefore, we believe that B2O3 can be used to synthesize a full range of α-U3O8 layered tantalate upconversion luminescent materials.

[0148] Figure 7 The SrTa4O prepared by the molten salt method using B2O3 as solvent under 980nm laser excitation in Examples 16, 19-21 is 11 :0.02Er 3+ / 0.04Yb 3+ , YTa7O 19 :0.1Er 3+ / 0.4Yb 3+ ,LaTa7O 19 :0.1Er 3+ / 0.4Yb 3+ ,BiTa7O 19 :0.1Er 3+ / 0.4Yb 3+ Samples and NaYF4:Er 3+ / Yb 3+ Upconversion spectrum of .

[0149] By calculating the fluorescence integral area of ​​up-converted green light, the SrTa4O 11 :0.02Er 3+ / 0.04Yb 3+ , YTa7O 19 :0.1Er 3+ / 0.4Yb 3+ ,LaTa7O 19 :0.1Er 3+ / 0.4Yb 3+ and BiTa7O 19 :0.1Er 3+ / 0.4Yb 3+ The samples are NaYF4:Er 3+ / Yb 3+ 15.07%, 114.14%, 112.38% and 132.73% respectively. This shows that the α-U3O8 structured tantalate phosphors have excellent pure green upconversion fluorescence performance, and YTa7O 19 :0.1Er 3+ / 0.4Yb 3+ ,LaTa7O 19 :0.1Er 3 + / 0.4Yb3+ ,BiTa7O 19 :0.1Er 3+ / 0.4Yb 3+ The fluorescence intensity has exceeded that of NaYF4:Er 3+ / Yb 3+ Phosphor.

[0150] Figure 8 In Example 16, SrTa4O was prepared by molten salt method using B2O3 as solvent under 980nm laser excitation. 11 :0.02Er 3+ / 0.04Yb 3+ Temperature spectrum of .

[0151] Under 980nm laser excitation, in the temperature range of 303 to 723K, Er 3+ Ionic 2 H 11 / 2 → 4 I 15 / 2 、 4 S 3 / 2 →4I 15 / 2 and 4 F 9 / 2 → 4 I 15 / 2 The transition emission light decreases with increasing temperature.

[0152] SrTa4O of Example 16 11 :0.02Er 3+ / 0.04Yb 3+ The relationship curve between the LIR value and temperature T can be calculated by the following formula:

[0153]

[0154] I H For Er 3+ of 2 H 11 / 2 → 4 I 15 / 2 Emission fluorescence integrated intensity value;

[0155] I S For Er 3+ of 4 S 3 / 2 → 4 I 15 / 2 The integrated intensity of emitted fluorescence; B is a constant, k B is the Boltzmann constant, ΔE is 2 H 11 / 2 and 4 S 3 / 2 The band gap between energy levels.

[0156] The fitted function is LIR = 27.55exp(-1013.27 / T), see Figure 9 .

[0157] Figure 9 It shows that the LIR value increases with increasing temperature, and there is a one-to-one correspondence.

[0158] Figure 10 Example 16, SrTa4O 11 :0.02Er 3+ / 0.04Yb 3+ A plot of the relationship between relative temperature sensitivity and temperature.

[0159] SrTa4O of Example 16 11 :0.02Er 3+ / 0.04Yb 3+ Relative temperature sensitivity S R The relationship curve between temperature T can be calculated by the following formula:

[0160]

[0161] Figure 10 It shows that the SrTa4O obtained in Example 16 11 :0.02Er 3+ / 0.04Yb 3+ , at 303K, the maximum relative temperature sensitivity can be obtained to be 0.0111K -1 , proves that SrTa4O 11 :0.02Er 3+ / 0.04Yb 3+ Luminescent materials have certain application prospects in the field of photothermal sensing.

[0162] Finally, the α-U3O8 layered tantalate upconversion luminescent material prepared by the present invention has the characteristics of pure green high brightness, high chemical stability and low toxicity, and is expected to replace commercial NaYF4:Er in some special application fields. 3+ / Yb 3+ Phosphor.

[0163] The embodiments described above are merely descriptions of preferred implementations of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should fall within the scope of protection determined by the claims of the present invention.

Claims

1. A method for preparing an α-U3O8 layered tantalate upconversion luminescent material, characterized in that: The α-U3O8 layered tantalate up-conversion luminescent material uses α-U3O8 layered tantalate as a matrix, and the matrix is ​​doped with Er. 3+ and Yb 3+ The chemical formula of the α-U3O8 layered tantalate is A x Ta 3n+1 O 8n+3 , where x=1, n=1, A is Sr; The preparation method of the α-U3O8 layered tantalate upconversion luminescent material comprises the following steps: S1: Weigh raw material 1, Er2O3, Yb2O3 and Ta2O5, mix and grind, the raw material 1 is the oxide or salt of A, A is Sr; according to A:Er 3+ :Yb 3+ :Ta 5+ =a:b:c:d molar ratio Weigh raw materials 1, Er2O3, Yb2O3 and Ta2O5, where a+b+c=1, d=4; S2: Mix the raw material mixture obtained in step S1 with 1 to 10 times the weight of B2O3 and sinter at 900°C for 4 to 24 hours; S3: After adding water to the material sintered in step S2 and filtering it, dry it for 2h-24h to obtain Er 3+ and Yb 3+ Co-doped α-U3O8 layered tantalate upconversion luminescent materials.

2. The method for preparing the α-U3O8 layered tantalate upconversion luminescent material according to claim 1, characterized in that: In step S1, a=0.94, b=0.02, c=0.

04.

3. The method for preparing the α-U3O8 layered tantalate upconversion luminescent material according to claim 1, characterized in that: The first raw material is Sr(NO3)2 or SrCO3.

4. The method for preparing the α-U3O8 layered tantalate upconversion luminescent material according to claim 1, characterized in that: In step S1, the grinding time is 30 minutes, and in step S3, the drying temperature is 80°C.

5. The method for preparing the α-U3O8 layered tantalate upconversion luminescent material according to claim 1, characterized in that: The purity of Sr salt, Er2O3, Yb2O3 and Ta2O5 is not less than 99.9%.

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