An erbium and ytterbium co-doped LaZrTa3O 11 Green upconversion luminescent material and its preparation method

Abstract

The present invention discloses an erbium and ytterbium co-doped LaZrTa3O 11 green upconversion luminescent material and a preparation method thereof. Among them, the erbium and ytterbium co-doped LaZrTa3O 11 green upconversion luminescent material uses LaZrTa3O 11 as a matrix, and Er 3+ and Yb 3+ are doped in the matrix. The chemical formula of the erbium and ytterbium co-doped LaZrTa3O 11 green upconversion luminescent material is (La a Er b Yb c )ZrTa3O 11 , where a = 0.94, b = 0.02, c = 0.04. The preparation method includes the following steps: weighing La2O3, Er2O3, Yb2O3, ZrO2, and Ta2O5 according to the molar ratio of each element in the chemical formula and mixing them; adding Bi2O3 for sintering, and through the steps of suction filtration, drying, pickling, re-suction filtration, and re-drying, an upconversion luminescent material is prepared. In the present invention, the LaZrTa3O 11 matrix is used for co-doping of Er 3+ and Yb 3+ ions. The prepared upconversion luminescent material has the characteristics of high temperature sensitivity, good chemical stability, and low toxicity, and has broad application prospects in the fields of biological imaging and optical temperature sensing, etc.

Description

Technical Field

[0001] The present invention relates to the field of upconversion luminescent materials, and particularly to an erbium-ytterbium co-doped LaZrTa3O 11 green upconversion luminescent material and a preparation method thereof. Background Art

[0002] Currently, NaYF4:Er 3+ / Yb 3+ upconversion phosphors are widely used in biomedicine, solar cells, photocatalysis, non-contact temperature measurement, anti-counterfeiting, and plant growth due to their excellent fluorescence intensity.

[0003] However, fluorides have certain toxicity and low temperature sensitivity, which to a certain extent limits the application fields of NaYF4:Er 3+ / Yb 3+ applications.

[0004] Therefore, it is very necessary to use oxides with high chemical stability to replace fluorides to prepare phosphors with high temperature sensitivity. Summary of the Invention

[0005] The present invention discloses an erbium-ytterbium co-doped LaZrTa3O 11 green upconversion luminescent material and a preparation method thereof, which solve the problems of toxicity and low temperature sensitivity of traditional upconversion luminescent materials NaYF4:Er 3+ / Yb 3+ while ensuring high brightness characteristics.

[0006] On the one hand, the present invention provides an erbium-ytterbium co-doped LaZrTa3O 11 green upconversion luminescent material, using LaZrTa3O 11 as a matrix, doped with Er 3+ and Yb 3+ in the matrix. The chemical formula of the erbium-ytterbium co-doped LaZrTa3O 11 green upconversion luminescent material is (La a Er b Yb c )ZrTa3O 11 , where a + b + c = 1.

[0007] Furthermore, in the chemical formula, a = 0.94, b = 0.02, c = 0.04.

[0008] The beneficial effects of the erbium-ytterbium co-doped LaZrTa3O 11 green upconversion luminescent material disclosed by the present invention:

[0009] The present invention for the first time uses the molten salt method to prepare LaZrTa3O 11 :Er 3+ / Yb 3+ upconversion phosphor with Ta2O5, La2O3, Er2O3, Yb2O3, ZrO2 as substrates and B2O3 as solvent. LaZrTa3O 11 has a layered structure, and Er 3+ / Yb 3+ ions are distributed in one layer in a 2D distribution. The prepared phosphor has efficient energy transfer from Yb 3+ to Er 3+ under 980 nm laser excitation, presents high-brightness pure green fluorescence, and has a temperature sensitivity of 0.01221 K -1 , and the integrated intensity of the green upconversion fluorescence reaches 29.2% of that of NaYF4:Er 3+ / Yb 3+ . The prepared LaZrTa3O 11 :Er 3+ / Yb 3+ upconversion phosphor has the advantages of high chemical stability and low toxicity, and is expected to replace the traditional NaYF4:Er 3+ / Yb 3+ upconversion phosphor in application fields such as acid-base environment, high-temperature environment, biomedicine and temperature sensing.

[0010] On the other hand, the present invention provides a method for preparing an erbium and ytterbium co-doped LaZrTa3O 11 green upconversion luminescent material, comprising the following steps:

[0011] S1: Weigh La2O3, Er2O3, Yb2O3, ZrO2, Ta2O5 respectively according to the molar ratio of each element in the chemical formula and mix them to obtain mixture Ⅰ;

[0012] S2: Mix 0.7 - 5.5 g of the mixture Ⅰ with 2 - 15 g of B2O3 to obtain mixture Ⅱ, and then sinter the mixture Ⅱ at 900 - 1200 °C for 4 - 24 hours;

[0013] S3: Filter, dry, acid-wash, filter again, and dry again the sintered sample to obtain the upconversion luminescent material.

[0014] Further, in S1, weigh the La2O3, Er2O3, Yb2O3, ZrO2, Ta2O5 respectively according to the molar ratio of 0.94:0.02:0.04:1:3.

[0015] Further, in S3, the specific method of the acid-washing is: use HCl with pH = 0 for acid-washing treatment for 6 h.

[0016] Further, before weighing and mixing, the La2O3 is pre-heat treated at 900 °C for 2 h. The heat treatment is to remove the moisture in the La2O3, which helps to improve the purity and stability of the material and facilitates the subsequent successful obtaining of a single-phase phosphor material sample.

[0017] Further, in S3, the drying temperature is 80 °C and the drying time is 2 h.

[0018] Further, in S1, the purities of the La2O3, Er2O3, Yb2O3, ZrO2, and Ta2O5 are all 99.9%.

[0019] The erbium and ytterbium co-doped LaZrTa3O 11 Beneficial effects of the preparation method of the green upconversion luminescent material:

[0020] In this method, La2O3, Er2O3, Yb2O3, ZrO2, and Ta2O5 are used as matrix raw materials, and B2O3 is added for sintering, and sintering is carried out in air. B2O3 can dissolve the oxides at high temperature as a solvent, making the oxides form free ions and react to form crystals. Finally, the hexagonal structured LaZrTa3O 11 :Er 3 + / Yb 3 + upconversion phosphor is prepared. In the method, pickling is used to remove B2O3 and other impurity residues on the surface of the sample, making the surface of the sample smoother, the purity of the prepared phosphor material higher, and the fluorescence intensity can be improved; this method uses the relatively low-temperature molten salt method to prepare the phosphor, which is easier to control the morphology and growth direction of the material particles, and Ta2O5 used in the raw materials of this method has a lower price, stable properties, no toxicity, no danger, and higher safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0022] Figure 1 It is the XRD test result diagram of the upconversion luminescent materials of Example 1, Example 2, and Example 3;

[0023] Figure 2 It is the upconversion fluorescence spectrum diagram of the upconversion luminescent materials of Example 1, Example 2, and Example 3 under 980 nm laser excitation;

[0024] Figure 3 XRD test result diagrams of the upconversion luminescent materials of Example 4, Example 5 and Example 6;

[0025] Figure 4 Upconversion fluorescence spectra diagrams of the upconversion luminescent materials of Example 4, Example 5 and Example 6 under 980 nm laser excitation;

[0026] Figure 5 XRD test result diagrams of the upconversion luminescent materials of Example 8, Example 9, Example 10 and Example 11;

[0027] Figure 6 Upconversion fluorescence spectra diagrams of the upconversion luminescent materials of Example 8, Example 9, Example 10 and Example 11 under 980 nm laser excitation;

[0028] Figure 7 SEM images of the upconversion luminescent materials of Example 4, Example 7, Example 9 and Example 10;

[0029] Figure 8 Upconversion fluorescence spectra diagrams of the upconversion luminescent material of Example 10 and NaYF4:Er 3+ / Yb 3+ under 980 nm laser excitation;

[0030] Figure 9 Variable-temperature upconversion fluorescence spectra diagrams of the upconversion luminescent material of Example 10 under 980 nm laser excitation;

[0031] Figure 10 Relationship diagram between the fluorescence branching ratio LIR value and temperature of the upconversion luminescent material of Example 10;

[0032] Figure 11 Relationship diagram between the relative temperature sensitivity and temperature of the upconversion luminescent material of Example 10. Detailed implementation manners

[0033] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0034] Embodiments

[0035] Example 1:

[0036] A preparation method of erbium and ytterbium co-doped LaZrTa3O 11 green upconversion luminescent material, comprising the following steps:

[0037] S1: Using La2O3, Er2O3, Yb2O3, ZrO2, Ta2O5 as matrix raw materials, according to the molar ratio of La 3+ :Er 3+ :Yb 3+ :Zr 4+ :Ta 5+ = 0.94:0.02:0.04:1:3, take 0.4620 g of La2O3, 0.0115 g of Er2O3, 0.0238 g of Yb2O3, 0.3718 g of ZrO2 and 2 g of Ta2O5, mix and grind them in a mortar for 30 minutes to obtain mixture I. La2O3 is pre-heat treated at 900 °C for 2 h;

[0038] S2: Add 15 g of B2O3 to mixture I (i.e., the mass ratio of the matrix raw material to the solvent B2O3 is about 1:1 (1:1.0456)) ， After mixing, sinter at 900 °C in an electric resistance furnace for 4 h;

[0039] S3: Filter the sintered sample by suction, and then put the obtained solid into an oven and dry it at 80 °C for 2 h to obtain the upconversion luminescent material (La 0.94 Er 0.02 Yb 0.04 )ZrTa3O 11 .

[0040] Example 2:

[0041] A preparation method of erbium and ytterbium co-doped LaZrTa3O 11 green upconversion luminescent material, comprising the following steps:

[0042] S1: Using La2O3, Er2O3, Yb2O3, ZrO2, Ta2O5 as matrix raw materials, according to the molar ratio of La 3+ :Er 3+ :Yb 3+ :Zr 4+ :Ta 5+ = 0.94:0.02:0.04:1:3, take 0.4620 g of La2O3, 0.0115 g of Er2O3, 0.0238 g of Yb2O3, 0.3718 g of ZrO2 and 2 g of Ta2O5, mix and grind them in a mortar for 30 minutes to obtain mixture I. La2O3 is pre-heat treated at 900 °C for 2 h;

[0043] S2: Add 15 g of B2O3 to Mixture I, mix them, and then sinter at 1100 °C for 4 h in an electric resistance furnace;

[0044] S3: Filter the sintered sample by suction, and then put the obtained solid into an oven and dry it at 80 °C for 2 h to obtain the upconversion luminescent material (La 0.94 Er 0.02 Yb 0.04 )ZrTa3O 11 .

[0045] Example 3:

[0046] A preparation method of erbium and ytterbium co-doped LaZrTa3O 11 green upconversion luminescent material, comprising the following steps:

[0047] S1: Using La2O3, Er2O3, Yb2O3, ZrO2, Ta2O5 as matrix raw materials, according to the molar ratio of La 3+ :Er 3+ :Yb 3+ :Zr 4+ :Ta 5+ = 0.94:0.02:0.04:1:3, take 0.4620 g of La2O3, 0.0115 g of Er2O3, 0.0238 g of Yb2O3, 0.3718 g of ZrO2 and 2 g of Ta2O5, mix and grind them in a mortar for 30 minutes to obtain Mixture I, and La2O3 is pre-treated at 900 °C for 2 h;

[0048] S2: Add 15 g of B2O3 to Mixture I, mix them, and then sinter at 1200 °C for 4 h in an electric resistance furnace;

[0049] S3: Filter the sintered sample by suction, and then put the obtained solid into an oven and dry it at 80 °C for 2 h to obtain the upconversion luminescent material (La 0.94 Er 0.02 Yb 0.04 )ZrTa3O 11 .

[0050] Example 4:

[0051] A preparation method of erbium and ytterbium co-doped LaZrTa3O 11 green upconversion luminescent material, comprising the following steps:

[0052] S1: Using La2O3, Er2O3, Yb2O3, ZrO2, Ta2O5 as matrix raw materials, according to the molar ratio of La 3+ :Er 3+ :Yb 3+ :Zr 4+: Ta 5+ = 0.94: 0.02: 0.04: 1: 3 molar ratio. Take 0.4620 g of La2O3, 0.0115 g of Er2O3, 0.0238 g of Yb2O3, 0.3718 g of ZrO2 and 2 g of Ta2O5, mix and grind them in a mortar for 30 minutes to obtain mixture I. La2O3 was pre-treated by heat treatment at 900 °C for 2 h;

[0053] S2: Add 15 g of B2O3 to mixture I, mix well, and sinter at 1100 °C for 24 h in an electric resistance furnace;

[0054] S3: Filter the sintered sample by suction, and then put the obtained solid into an oven and dry it at 80 °C for 2 h to obtain the upconversion luminescent material (La 0.94 Er 0.02 Yb 0.04 )ZrTa3O 11 .

[0055] Example 5:

[0056] A preparation method of erbium and ytterbium co-doped LaZrTa3O 11 green upconversion luminescent material, comprising the following steps:

[0057] S1: Using La2O3, Er2O3, Yb2O3, ZrO2, Ta2O5 as matrix raw materials, according to La 3+ : Er 3+ : Yb 3+ : Zr 4+ : Ta 5+ = 0.94: 0.02: 0.04: 1: 3 molar ratio. Take 0.4620 g of La2O3, 0.0115 g of Er2O3, 0.0238 g of Yb2O3, 0.3718 g of ZrO2 and 2 g of Ta2O5, mix and grind them in a mortar for 30 minutes to obtain mixture I. La2O3 was pre-treated by heat treatment at 900 °C for 2 h;

[0058] S2: Add 15 g of B2O3 to mixture I, mix well, and sinter at 1150 °C for 24 h in an electric resistance furnace;

[0059] S3: Filter the sintered sample by suction, and then put the obtained solid into an oven and dry it at 80 °C for 2 h to obtain the upconversion luminescent material (La 0.94 Er 0.02 Yb 0.04 )ZrTa3O 11 .

[0060] Example 6:

[0061] Preparation method of erbium and ytterbium co-doped LaZrTa3O 11 green up-conversion luminescent material, comprising the following steps:

[0062] S1: Using La2O3, Er2O3, Yb2O3, ZrO2, Ta2O5 as matrix raw materials, according to the molar ratio of La 3+ :Er 3+ :Yb 3+ :Zr 4+ :Ta 5+ = 0.94:0.02:0.04:1:3, take 0.4620 g of La2O3, 0.0115 g of Er2O3, 0.0238 g of Yb2O3, 0.3718 g of ZrO2 and 2 g of Ta2O5, mix and grind in a mortar for 30 minutes to obtain mixture I. La2O3 is pre-treated by heat treatment at 900 °C for 2 h;

[0063] S2: Add 15 g of B2O3 to mixture I, mix well, and sinter in an electric resistance furnace at 1200 °C for 24 h;

[0064] S3: Filter the sintered sample by suction, then put the obtained solid into an oven and dry it at 80 °C for 2 h to obtain the up-conversion luminescent material (La 0.94 Er 0.02 Yb 0.04 )ZrTa3O 11 .

[0065] Example 7:

[0066] Preparation method of erbium and ytterbium co-doped LaZrTa3O 11 green up-conversion luminescent material, comprising the following steps:

[0067] S1: Using La2O3, Er2O3, Yb2O3, ZrO2, Ta2O5 as matrix raw materials, according to the molar ratio of La 3+ :Er 3+ :Yb 3+ :Zr 4+ :Ta 5+ = 0.94:0.02:0.04:1:3, take 0.4620 g of La2O3, 0.0115 g of Er2O3, 0.0238 g of Yb2O3, 0.3718 g of ZrO2 and 2 g of Ta2O5, mix and grind in a mortar for 30 minutes to obtain mixture I. La2O3 is pre-treated by heat treatment at 900 °C for 2 h;

[0068] S2: Add 15 g of B2O3 to mixture I, mix well, and sinter in an electric resistance furnace at 1100 °C for 24 h;

[0069] S3: The sintered samples are subjected to suction filtration, and then the obtained solid is placed in an oven and dried at 80 °C for 2 h. The dried sample is put into an HCl solution with pH = 0 for pickling treatment for 6 h, and then the sample is subjected to suction filtration again, and then placed in the oven and dried at 80 °C for 2 h to obtain the upconversion luminescent material (La 0.94 Er 0.02 Yb 0.04 )ZrTa3O 11 。

[0070] Example 8:

[0071] A preparation method of erbium and ytterbium co-doped LaZrTa3O 11 green upconversion luminescent material, comprising the following steps:

[0072] S1: Take La2O3, Er2O3, Yb2O3, ZrO2, Ta2O5 as matrix raw materials, according to La 3+ : Er 3+ : Yb 3+ : Zr 4+ : Ta 5+ = 0.94:0.02:0.04:1:3 molar ratio, take 0.4620 g of La2O3, 0.0115 g of Er2O3, 0.0238 g of Yb2O3, 0.3718 g of ZrO2 and 2 g of Ta2O5, mix and grind with a mortar for 30 minutes to obtain mixture Ⅰ, and La2O3 is pre-treated by heat treatment at 900 °C for 2 h;

[0073] S2: Add 2 g of B2O3 to mixture Ⅰ, mix, and sinter in an electric resistance furnace at 1100 °C for 24 h;

[0074] S3: The sintered samples are subjected to suction filtration, and then the obtained solid is placed in an oven and dried at 80 °C for 2 h to obtain the upconversion luminescent material (La 0.94 Er 0.02 Yb 0.04 )ZrTa3O 11 。

[0075] Example 9:

[0076] A preparation method of erbium and ytterbium co-doped LaZrTa3O 11 green upconversion luminescent material, comprising the following steps:

[0077] S1: Take La2O3, Er2O3, Yb2O3, ZrO2, Ta2O5 as matrix raw materials, according to La 3+ : Er 3+ : Yb 3+ : Zr4+ : Ta 5+ = 0.94: 0.02: 0.04: 1: 3 in molar ratio. Take 0.4620 g of La2O3, 0.0115 g of Er2O3, 0.0238 g of Yb2O3, 0.3718 g of ZrO2 and 2 g of Ta2O5, mix and grind them in a mortar for 30 minutes to obtain Mixture I. La2O3 was pre-heat-treated at 900 °C for 2 h;

[0078] S2: Add 3 g of B2O3 to Mixture I, mix them, and then sinter at 1100 °C in an electric resistance furnace for 24 h;

[0079] S3: Filter the sintered sample by suction, then put the obtained solid into an oven and dry it at 80 °C for 2 h to obtain the upconversion luminescent material (La 0.94 Er 0.02 Yb 0.04 )ZrTa3O 11 .

[0080] Example 10:

[0081] A preparation method of erbium and ytterbium co-doped LaZrTa3O 11 green upconversion luminescent material, comprising the following steps:

[0082] S1: Take La2O3, Er2O3, Yb2O3, ZrO2, Ta2O5 as matrix raw materials. According to La 3+ : Er 3+ : Yb 3+ : Zr 4+ : Ta 5+ = 0.94: 0.02: 0.04: 1: 3 in molar ratio. Take 0.4620 g of La2O3, 0.0115 g of Er2O3, 0.0238 g of Yb2O3, 0.3718 g of ZrO2 and 2 g of Ta2O5, mix and grind them in a mortar for 30 minutes to obtain Mixture I. La2O3 was pre-heat-treated at 900 °C for 2 h;

[0083] S2: Add 3 g of B2O3 to Mixture I, mix them, and then sinter at 1100 °C in an electric resistance furnace for 24 h;

[0084] S3: Filter the sintered sample by suction, then put the obtained solid into an oven and dry it at 80 °C for 2 h. Put the dried sample into a HCl solution with pH = 0 for pickling treatment for 6 h, then filter the sample by suction again, and then put it into the oven and dry it at 80 °C for 2 h to obtain the upconversion luminescent material (La 0.94 Er 0.02 Yb 0.04 )ZrTa3O11 。

[0085] Example 11:

[0086] A preparation method of erbium-ytterbium co-doped LaZrTa3O 11 green upconversion luminescent material, comprising the following steps:

[0087] S1: Take La2O3, Er2O3, Yb2O3, ZrO2, Ta2O5 as matrix raw materials, according to La 3+ :Er 3+ :Yb 3+ :Zr 4+ :Ta 5+ = 0.94:0.02:0.04:1:3 molar ratio, take 0.4620 g of La2O3, 0.0115 g of Er2O3, 0.0238 g of Yb2O3, 0.3718 g of ZrO2 and 2 g of Ta2O5, mix and grind with a mortar for 30 minutes to obtain mixture Ⅰ. La2O3 is pre-heat-treated at 900 °C for 2 h;

[0088] S2: Add 5 g of B2O3 to mixture Ⅰ, mix, and sinter in an electric resistance furnace at 1100 °C for 24 h;

[0089] S3: Filter the sintered sample by suction, and then put the obtained solid into an oven and dry it at 80 °C for 2 h to obtain the upconversion luminescent material (La 0.94 Er 0.02 Yb 0.04 )ZrTa3O 11 。

[0090] The temperatures, times, solvent amounts and whether there is an acid washing step set in Examples 1-11 are shown in Table 1 below.

[0091] Table 1: Parameters and dosage table of Examples 1-11

[0092] Sample Number Temperature Time Solvent Quantity Whether Acid Pickling is Conducted Example 1 900 4 15g No Acid Pickling Example 2 1100 4 15g No Acid Pickling Example 3 1200 4 15g No Acid Pickling Example 4 1100 24 15g No Acid Pickling Example 5 1150 24 15g No Acid Pickling Example 6 1200 24 15g No Acid Pickling Example 7 1100 24 15g Acid Pickling Example 8 1100 24 2g No Acid Pickling Example 9 1100 24 3g No Acid Pickling Example 10 1100 24 3g Acid Pickling Example 11 1100 24 5g No Acid Pickling

[0093] Comparative example:

[0094] Existing NaYF4:Er 3+ / Yb 3+ luminescent material (Shenzhen Zhanwanglong Technology Co., Ltd., 980 nm infrared upconversion excited green NaYF4 anti-counterfeiting fluorescent powder for labeling biological probes).

[0095] Performance detection test

[0096] 1. The upconversion luminescent materials prepared in the above Examples 1-10 and Comparative Example 1 were subjected to performance testing. A copper target was used for the test, and the equipment was XRD-Rigaku D / MAX RE, and the incident wavelength was

[0097] The test results are shown in Figure 1 、 Figure 3 、 Figure 5 :

[0098] 2. The relative green light integrated intensity (performance of green phosphor) of the upconversion luminescent materials prepared in the above Examples 1-10 and Comparative Example 1 under 980 nm laser excitation (18.09 W / cm 2 ) was detected. The 980 nm laser was produced by Changchun New Industry Co., Ltd., and the laser power density varied from 0 to 60 W / cm 2 . The test instrument was Hitachi F-4600 fluorescence spectrometer, and the test results are shown in Figure 2 、 Figure 4 、 Figure 6 、 Figure 8 .

[0099] Figure 1 It shows the relative fluorescence intensity comparison results of the LaZrTa3O 11 :0.02Er 3+ / 0.04Yb 3+ ((La 0.94 Er 0.02 Yb 0.04 )ZrTa3O 11 ) samples prepared by the molten salt method using 15 g B2O3 as the solvent and sintered at 900 °C (Example 1), 1100 °C (Example 2), and 1200 °C (Example 3) for 4 h respectively. As can be seen from Figure 1 , a single-phase LaZrTa3O 11 :0.02Er 3+ / 0.04Yb 3+ cannot be formed at 900 °C. A single-phase LaZrTa3O 11 :0.02Er 3+ / 0.04Yb 3+ can be formed at 1100 °C. When the temperature rises to 1200 °C, a small amount of Ta2O5 and ZrO2 impurities appear in the sample; as can be seen from Figure 2 , as the reaction temperature rises from 900 °C to 1200 °C, the upconversion fluorescence intensity of the sample increases; as can be seen from Figure 3 , in Example 4, under the condition of a reaction time of 24 h, the sintering temperature of 1100 °C is the optimal temperature, and the prepared sample is a single-phase LaZrTa3O 11: 0.02 Er 3+ / 0.04 Yb 3+ , as the temperature increases, the sample gradually transforms into β-Ta2O5. When the temperature reaches 1200 °C (Example 6), the sample structure is consistent with β-Ta2O5. Therefore, to prepare LaZrTa3O 11 : 0.02 Er 3+ / 0.04 Yb 3+ the optimal condition is sintering at 1100 °C for 24 h; from Figure 4 it can be seen that among Examples 4 - 6, the single-phase LaZrTa3O prepared by sintering at 1100 °C for 24 h in Example 4 11 : 0.02 Er 3+ / 0.04 Yb 3+ has the best up-conversion fluorescence intensity; as Figure 5 shown, the XRD results of the samples prepared in Examples 8 - 11 using 2 g, 3 g, and 5 g of B2O3 solvent amounts and pickling treatment have no impurity peaks, that is, the prepared LaZrTa3O 11 : 0.02 Er 3+ / 0.04 Yb 3+ phosphors are all single-phase; as Figure 6 shown, the sample prepared in Example 10 using 3 g of B2O3 solvent has the best up-conversion fluorescence intensity, and after pickling treatment, the fluorescence intensity can be further improved; from Figure 8 it can be seen that the fluorescence integral intensity of the up-conversion green phosphor prepared in Example 10 reaches 29.2% of NaYF4: Er 3+ / Yb 3+ , and the emission light is around 500 nm, with high brightness and pure green characteristics.

[0100] 3. The up-conversion luminescent materials prepared in Example 4, Example 7, Example 9, and Example 10 were scanned by scanning electron microscopy (SEM-ZEISS Sigma 300, Germany). The SEM images are as Figure 7 shown. From Figure 7 it can be seen that the single-phase LaZrTa3O prepared in Example 10 11 : 0.02 Er 3+ / 0.04 Yb 3+ up-conversion luminescent material has a regular hexagonal plate-like morphology. After pickling treatment, the B2O3 and other small molecule impurities on the sample surface are removed, and its morphology becomes smoother. Therefore, the up-conversion fluorescence intensity of the sample is improved.

[0101] 4. Test the up-conversion luminescent material prepared in Example 10 above under 980 nm laser excitation (5.48 W / cm2 ), in the temperature range of 303 to 723 K, LaZrTa3O 11 :0.02Er 3+ / 0.04Yb 3+ temperature-dependent upconversion spectra, see Figure 9 , from Figure 9 it can be seen that the 3+ emission of Er 2 H 11 / 2 → 4 I 15 / 2 , 4 S 3 / 2 →4I 15 / 2 and 4 F 9 / 2 → 4 I 15 / 2 transition emission light decreases with increasing temperature.

[0102] According to Figure 9 the relationship curve between the IH and IS fluorescence intensity branching ratio (LIR value) calculated from the spectral data in

[0103]

[0104] I H is the integrated fluorescence intensity value of the 3+ emission of Er 2 H 11 / 2 → 4 I 15 / 2 ;

[0105] I S is the integrated fluorescence intensity value of the 3+ emission of Er 4 S 3 / 2 → 4 I 15 / 2 ; B is a constant, k B is the Boltzmann constant, and ΔE is 2 the energy band gap between the 11 / 2 H 4 and 3 / 2 S energy levels.

[0106] The fitted function is LIR = 33.80exp(-1119.44 / T), see Figure 10 , from Figure 10 it can be seen that the LIR value (I H / I S value) increases with increasing temperature.

[0107] 5. Calculate the absolute temperature sensitivity S of the upconversion luminescent material prepared in Example 10 aboveR Relationship with temperature, S R The relationship curve between S and temperature T can be calculated by the following formula:

[0108]

[0109] The calculation results are as Figure 11 shown. It can be seen from Figure 11 that for LaZrTa3O 11 :0.02Er 3+ / 0.04Yb 3+ prepared in Example 10, the maximum relative temperature sensitivity S A is 0.01221K -1 at 303K, which proves that LaZrTa3O 11 :0.02Er 3+ / 0.04Yb 3+ luminescent materials have certain application prospects in the field of photothermal sensing.

[0110] Therefore, the optimal sintering conditions for the LaZrTa3O 11 :0.02Er 3+ / 0.04Yb 3+ luminescent materials prepared in this invention are sintering at 1100°C for 24h. After pickling, the prepared upconversion luminescent materials can make LaZrTa3O 11 single-phase, and the morphology is smoother. The LaZrTa3O 11 :0.02Er 3+ / 0.04Yb 3+ upconversion luminescent materials prepared in this invention have the characteristics of pure green high brightness, high chemical stability and low toxicity, and are expected to replace commercial NaYF4:Er 3+ / Yb 3+ phosphors in some special application fields.

[0111] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An erbium and ytterbium co-doped LaZrTa3O 11 green upconversion luminescent material, characterized in that, Using LaZrTa3O 11 as the matrix, Er 3+ and Yb 3+ are doped in the matrix. The chemical formula of the erbium and ytterbium co-doped LaZrTa3O 11 green upconversion luminescent material is (La a Er b Yb c )ZrTa3O 11 , where a + b + c = 1.

2. An erbium and ytterbium co-doped LaZrTa3O 11 green upconversion luminescent material, characterized in that In the described chemical formula, a = 0.94, b = 0.02, and c = 0.

04.

3. Preparation method of erbium-ytterbium co-doped LaZrTa3O 11 green upconversion luminescent material, characterized in that, It includes the following steps: S1: Weigh La2O3, Er2O3, Yb2O3, ZrO2, and Ta2O5 according to the molar ratios of the respective elements in the chemical formula and mix them to obtain Mixture I. S2: Mix 0.7 - 5.5 g of the said Mixture I with 2 - 15 g of B2O3 to obtain Mixture II, and then sinter Mixture II at 1100 - 1150 °C for 4 - 24 hours. S3: Perform suction filtration, drying, pickling, re - suction filtration, and re - drying on the sintered sample to obtain the up - conversion luminescent material.

4. The preparation method of the erbium and ytterbium co-doped LaZrTa3O 11 green upconversion luminescent material, characterized in that, In S1, weigh the said La2O3, Er2O3, Yb2O3, ZrO2, and Ta2O5 according to the molar ratio of 0.94:0.02:0.04:1:

3.

5. The preparation method of the erbium and ytterbium co-doped LaZrTa3O 11 green upconversion luminescent material, characterized in that In S3, the specific method of pickling is: use HCl with pH = 0 for pickling treatment for 6 h.

6. The preparation method of the erbium and ytterbium co-doped LaZrTa3O 11 green upconversion luminescent material, characterized in that Before weighing and mixing, the La2O3 is pre-treated by heat treatment at 900 o °C for 2 h.

7. The preparation method of the erbium and ytterbium co-doped LaZrTa3O 11 green upconversion luminescent material, characterized in that, In S3, the drying temperature is 80 o °C, and the drying time is 2 h.

8. The preparation method of the erbium and ytterbium co-doped LaZrTa3O 11 green upconversion luminescent material, characterized in that, In S1, the purities of the said La2O3, Er2O3, Yb2O3, ZrO2, and Ta2O5 are all 99.9%.

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