An erbium-ytterbium co-doped beta-Ta2O5 green up-conversion luminescent material and a preparation method thereof

Abstract

This invention discloses an erbium-ytterbium co-doped β-Ta₂O₅ green upconversion luminescent material and its preparation method. The luminescent material uses β-Ta₂O₅ as a matrix and dops Er₂ within it. 3+ and Yb 3+ The luminescent material has the chemical formula β-Ta₂O₅:aEr 3+ / bYb 3+ Where a:b = 1:2~15, a = 0.003~0.01. The preparation method includes steps such as raw material mixing, grinding, sintering, filtration, and drying. The erbium-ytterbium co-doped β-Ta₂O₅ green upconversion luminescent material prepared by this invention uses β-Ta₂O₅ as the matrix and co-doped with Er 3+ and Yb 3+ It exhibits higher chemical stability, lower toxicity, significantly enhanced green upconversion fluorescence intensity, and greater temperature sensitivity. These properties effectively improve the performance of NaYF4:Er 3+ / Yb 3+ The instability and safety issues inherent in phosphors make this material a promising candidate for specific applications such as photothermal sensing, and it holds the potential to replace the commercial phosphor product NaYF4:Er. 3+ / Yb 3+ .

Description

Technical Field

[0001] This invention relates to the field of upconversion luminescent materials technology, and in particular to an erbium-ytterbium co-doped β-Ta2O5 green upconversion luminescent material and its preparation method. Background Technology

[0002] In the field of optical materials, rare-earth-doped upconversion phosphors have attracted much attention due to their unique energy conversion mechanism, namely, their ability to convert long-wavelength, low-energy light into short-wavelength, high-energy light. Among them, NaYF4:Er 3+ / Yb 3+ Upconversion phosphors stand out in numerous applications due to their superior fluorescence efficiency, high quantum yield, and good luminescence stability, especially in biomedical imaging, high-efficiency solar cells, photocatalytic reaction promotion, non-contact temperature measurement systems, advanced anti-counterfeiting technologies, and optical regulation to promote plant growth, demonstrating great application potential.

[0003] However, despite NaYF4:Er 3+ / Yb 3+ While phosphors offer numerous advantages, their insufficient chemical stability and potential toxicity are key factors limiting their wider application. Fluoride-based materials are prone to hydrolysis or corrosion in aqueous solutions and certain chemical environments, leading to decreased or even lost fluorescence performance. This poses a significant challenge to applications requiring long-term material stability and safety (such as in vivo implantation and long-term environmental monitoring). Furthermore, the toxicity of fluorides, especially in the event of leakage or improper handling, can adversely affect the environment and organisms, increasing the risks and costs associated with their use. Summary of the Invention

[0004] This invention provides an erbium-ytterbium co-doped β-Ta₂O₅ green upconversion luminescent material and its preparation method, replacing fluorides with a β-Ta₂O₅ matrix that has higher chemical stability and lower toxicity, thereby increasing the erbium-ytterbium content of fluorinated materials. 3+ and Yb 3+ By effectively doping with rare earth ions, the chemical stability and safety of the material are significantly improved while enhancing the original upconversion luminescence performance, thus overcoming the shortcomings of fluoride-based phosphors.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows:

[0006] A green upconversion luminescent material co-doped with erbium and ytterbium (Er) is disclosed, using β-Ta₂O₅ as a matrix and doping the matrix with Er. 3+ and Yb 3+ .

[0007] Furthermore, the luminescent material has the chemical formula β-Ta2O5:aEr 3+ / bYb 3+ , where a:b=1:2~15, a=0.003~0.01.

[0008] Furthermore, the chemical formula of the luminescent material is β-Ta₂O₅:0.01Er. 3+ / 0.02Yb 3+ .

[0009] Furthermore, the luminescent material has the chemical formula β-Ta₂O₅:0.0038Er. 3+ / 0.05Yb 3+ .

[0010] To achieve the above objectives, the present invention also provides a method for preparing erbium-ytterbium co-doped β-Ta₂O₅ green upconversion luminescent material, characterized by comprising the following steps:

[0011] S1: Weigh out the raw materials Ta2O5, Er2O3 and Yb2O3, mix them evenly and grind them thoroughly;

[0012] S2: Add B2O3 and Sr(NO3)2 to the material ground in S1 and mix thoroughly. The amount of B2O3 added is 1.5 to 8 times the mass of Ta2O5, and the molar ratio of the amount of B2O3 to Sr(NO3)2 added is 1:0.0015 to 0.006.

[0013] S3: Sinter the well-mixed material described in S2 at 800-1200℃ for 18-30 hours;

[0014] S4: The product sintered in S3 is subjected to solid-liquid separation, and the solid is dried to obtain the luminescent material.

[0015] Furthermore, the molar ratio of the raw materials Ta2O5, Er2O3 and Yb2O3 is Ta2O5:Er2O3:Yb2O3=1:a:b.

[0016] Further, the luminescent material obtained by drying in S4 is acid-washed in an acidic solution with a pH of 0 to 4 for 5 to 7 hours, followed by solid-liquid separation. The solid is then dried to obtain the acid-washed luminescent material.

[0017] Furthermore, the acid solution is an HCl solution.

[0018] Furthermore, the drying time is 1 to 4 hours.

[0019] Furthermore, the purity of Er2O3, Yb2O3, and Ta2O5 is all above 99.9%.

[0020] In summary, the present invention has the following beneficial effects:

[0021] First, the matrix β-Ta₂O₅ used in this invention has a layered structure, composed of TaO₆ and TaO₇ units. β-Ta₂O₅ has low phonon energy, making it highly suitable for Er doping. 3+ / Yb 3+ As an upconversion fluorescent material, β-Ta2O5 also exhibits greater stability and biocompatibility than fluorides.

[0022] Secondly, the green upconversion phosphor prepared by this invention exhibits excellent green upconversion fluorescence intensity. Under 980nm laser excitation, it displays high-brightness pure green fluorescence. The integrated intensity of the green upconversion fluorescence reaches that of commercial phosphor product NaYF4:Er 3+ / Yb 3+ 86.7%.

[0023] Third, the green upconversion luminescent material prepared by this invention exhibits higher temperature sensitivity. The maximum relative temperature sensitivity, calculated using fluorescence intensity branching ratio (LIR) technology, is 0.01145 K. -1 This result indicates that the luminescent material prepared in this invention has good application prospects in specific fields such as photothermal sensing, and is expected to replace commercial NaYF4:Er 3+ / Yb 3+ Fluorescent powder.

[0024] Fourth, this invention employs a solvent molten salt method, achieving precise control over the luminescent material preparation process through fine adjustment of various synthesis parameters, thereby controlling its morphology to a uniform columnar structure. This uniform columnar structure not only endows the material with higher physical stability but also helps to improve the photon transmission path and efficiency, thus enhancing photoelectric conversion performance.

[0025] Fifth, the introduction of an acid washing step in the preparation method effectively removes solvent residues and impurities from the material surface, thereby significantly improving the purity of the final product. Attached Figure Description

[0026] 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.

[0027] Figure 1 These are X-ray diffraction results of the luminescent materials prepared in Examples 1-6 of this invention.

[0028] Figure 2 The upconversion fluorescence spectra of the luminescent materials prepared in Examples 2, 4, 5, and 6 are obtained under 980nm laser excitation.

[0029] Figure 3 This is a comparison of the upconversion fluorescence spectra of the luminescent materials prepared in Examples 1 and 2 under 980nm laser excitation.

[0030] Figure 4 This is a comparison of the upconversion fluorescence spectra of the luminescent materials prepared in Examples 3 and 4 under 980nm laser excitation.

[0031] Figure 5 These are scanning electron microscope (SEM) images of the luminescent materials prepared in Examples 3, 4, and 5.

[0032] Figure 6 The luminescent material and NaYF4:Er prepared in Example 5 under 980nm laser excitation 3+ / Yb 3+ The upconversion fluorescence spectrum.

[0033] Figure 7 The image shows the temperature-varying upconversion fluorescence spectrum of the luminescent material prepared in Example 5 under 980nm laser excitation.

[0034] Figure 8 This is a graph showing the relationship between the fluorescence branching ratio (LIR) value of the luminescent material prepared in Example 5 and temperature.

[0035] Figure 9 This is a graph showing the relationship between the relative temperature sensitivity of the luminescent material prepared in Example 5 and temperature. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of 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, 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.

[0037] This invention provides an erbium-ytterbium co-doped β-Ta₂O₅ green upconversion luminescent material and its preparation method, replacing fluorides with a β-Ta₂O₅ matrix that has higher chemical stability and lower toxicity, thereby increasing the erbium-ytterbium content of fluorinated materials. 3+ and Yb 3+ By effectively doping with rare earth ions, the chemical stability and safety of the material are significantly improved while enhancing the original upconversion luminescence performance, thus overcoming the shortcomings of fluoride-based phosphors.

[0038] To achieve the above objectives, the technical solution of the present invention is as follows:

[0039] A green upconversion luminescent material co-doped with erbium and ytterbium (Er) is disclosed, using β-Ta₂O₅ as a matrix and doping the matrix with Er. 3+ and Yb 3+ .

[0040] Furthermore, the luminescent material has the chemical formula β-Ta2O5:aEr 3+ / bYb 3+ , where a:b=1:2~15, a=0.003~0.01.

[0041] β-Ta₂O₅ exhibits greater stability and biocompatibility than fluorides. It has a layered structure composed of TaO₆ and TaO₇ units and low phonon energy, making it highly suitable as a matrix dopant for Er. 3+ / Yb 3+ The prepared upconversion fluorescent material exhibits an integrated fluorescence intensity of upconverted green light that matches that of the commercial phosphor product NaYF4:Er. 3+ / Yb 3+ More than 18.8%.

[0042] Furthermore, the upconversion luminescent material has the chemical formula β-Ta₂O₅:0.01Er. 3+ / 0.02Yb 3+ .

[0043] After optimizing the erbium-ytterbium co-doping ratio, the fluorescence integral intensity of the upconversion green light of the prepared fluorescent material can reach that of the commercial phosphor product NaYF4:Er 3+ / Yb 3+ 49.4%.

[0044] Furthermore, the upconversion luminescent material has the chemical formula β-Ta₂O₅:0.0038Er. 3+ / 0.05Yb 3+ .

[0045] After optimizing the erbium-ytterbium co-doping ratio, the prepared fluorescent material exhibited high-brightness pure green fluorescence under 980nm laser excitation, with an integrated intensity reaching that of commercial phosphor product NaYF4:Er 3+ / Yb 3+ It has a temperature sensitivity of 86.7%. Furthermore, it exhibits higher temperature sensitivity, with a maximum relative temperature sensitivity of 0.01145 K calculated using fluorescence intensity branching ratio (LIR) technology. -1 It has promising applications in specific fields such as photothermal sensing and is expected to replace commercial NaYF4:Er 3+ / Yb 3+ Fluorescent powder.

[0046] This invention also provides a method for preparing erbium-ytterbium co-doped β-Ta₂O₅ green upconversion luminescent material, characterized by comprising the following steps:

[0047] S1: Weigh out the raw materials Ta2O5, Er2O3 and Yb2O3, mix them evenly and grind them thoroughly;

[0048] S2: Add B2O3 and Sr(NO3)2 to the material ground in S1 and mix thoroughly. The amount of B2O3 added is 1.5 to 8 times the mass of Ta2O5, and the molar ratio of the amount of B2O3 to Sr(NO3)2 added is 1:0.0015 to 0.006.

[0049] S3: Sinter the well-mixed material described in S2 at 800-1200℃ for 18-30 hours;

[0050] S4: The product sintered in S3 is subjected to solid-liquid separation, and the solid is dried to obtain the luminescent material.

[0051] Furthermore, the molar ratio of the raw materials Ta2O5, Er2O3 and Yb2O3 is Ta2O5:Er2O3:Yb2O3=1:a:b.

[0052] This method employs a solvent molten salt method to prepare erbium-ytterbium co-doped β-Ta₂O₅ green upconversion luminescent materials. Precise control of the synthesis process was achieved through fine adjustment of various synthesis parameters, resulting in a uniform columnar structure. This uniform columnar structure not only endows the material with higher physical stability but also improves the photon transmission path and efficiency, thereby enhancing its photoelectric conversion performance.

[0053] Further, the luminescent material obtained by drying in S4 is acid-washed in an acidic solution with a pH of 0 to 4 for 5 to 7 hours, followed by solid-liquid separation. The solid is then dried to obtain the acid-washed luminescent material.

[0054] In this preparation method, liquid B2O3 and Sr(NO3)2 solvents are removed by solid-liquid separation at high temperature, and an acid washing step is introduced into the dried product to further remove solvent residues and impurities on the material surface, thereby significantly improving the purity of the final product.

[0055] Furthermore, the acid solution is an HCl solution.

[0056] Furthermore, the drying time is 1 to 4 hours.

[0057] Furthermore, the purity of Er2O3, Yb2O3, and Ta2O5 is all above 99.9%.

[0058] By optimizing the above-mentioned preparation process parameters, precise control of the processing of erbium-ytterbium co-doped β-Ta₂O₅ green upconversion luminescent materials was achieved. The prepared luminescent materials exhibit high purity, high safety, better chemical stability, and lower toxicity, with significantly enhanced green upconversion fluorescence intensity and greater temperature sensitivity, thus improving the NaYF₄:Er 3+ / Yb 3+ Despite the instability and safety issues associated with phosphors, they hold promising application potential in specific fields such as photothermal sensing and are expected to replace commercially available NaYF4:Er. 3+ / Yb 3+ Fluorescent powder.

[0059] Example 1

[0060] Preparation of erbium-ytterbium co-doped β-Ta₂O₅ green upconversion luminescent materials by solvent molten salt method:

[0061] S1: Massager Ta 5+ :Er 3+ :Yb 3+ =2:0.01:0.02, weigh 2g of Ta2O5, 0.0087g of Er2O3, and 0.0178g of Yb2O3 respectively, mix them evenly, and grind them thoroughly for 30min;

[0062] S2: Add 15g of B2O3 and 0.0958g of Sr(NO3)2 to the material ground in S1 and mix thoroughly. The amount of B2O3 added is 7.5 times the mass of Ta2O5, and the molar ratio of B2O3 to Sr(NO3)2 added is 1:0.0015.

[0063] S3: Sinter the well-mixed material described in S2 at 1000℃ for 30 hours;

[0064] S4: After sintering the product in S3, filter it and place it in an oven to dry at 80°C for 2 hours to obtain the luminescent material.

[0065] Example 2

[0066] Preparation of erbium-ytterbium co-doped β-Ta₂O₅ green upconversion luminescent materials by solvent molten salt method:

[0067] S1: Massager Ta 5+ :Er 3+ :Yb 3+ =2:0.01:0.02, weigh 2g of Ta2O5, 0.0087g of Er2O3, and 0.0178g of Yb2O3 respectively, mix them evenly, and grind them thoroughly for 30min;

[0068] S2: Add 15g of B2O3 and 0.0958g of Sr(NO3)2 to the material ground in S1 and mix thoroughly. The amount of B2O3 added is 7.5 times the mass of Ta2O5, and the molar ratio of B2O3 to Sr(NO3)2 added is 1:0.0015.

[0069] S3: Sinter the well-mixed material described in S2 at 1000℃ for 30 hours;

[0070] S4: After the product sintered in S3 is filtered, it is placed in an oven and dried at 80℃ for 2 hours.

[0071] S5: The dried sample was placed in an HCl solution at pH 4 for acid washing for 6 hours, then filtered and dried in an oven at 80°C for 2 hours to obtain the luminescent material.

[0072] Example 3

[0073] Preparation of erbium-ytterbium co-doped β-Ta₂O₅ green upconversion luminescent materials by solvent molten salt method:

[0074] S1: Massager Ta 5+ :Er 3+ :Yb 3+ =2:0.01:0.02, weigh 2g of Ta2O5, 0.0087g of Er2O3, and 0.0178g of Yb2O3 respectively, mix them evenly, and grind them thoroughly for 30min;

[0075] S2: Add 3g of B2O3 and 0.0479g of Sr(NO3)2 to the material ground in S1 and mix thoroughly. The amount of B2O3 added is 1.5 times the mass of Ta2O5, and the molar ratio of B2O3 to Sr(NO3)2 added is 1:0.0038.

[0076] S3: Sinter the well-mixed material described in S2 at 1100℃ for 18 hours;

[0077] S4: After sintering the product in S3, filter it and place it in an oven to dry at 80°C for 2 hours to obtain the luminescent material.

[0078] Example 4

[0079] Preparation of erbium-ytterbium co-doped β-Ta₂O₅ green upconversion luminescent materials by solvent molten salt method:

[0080] S1: Massager Ta 5+ :Er 3+ :Yb 3+=2:0.01:0.02, weigh 2g of Ta2O5, 0.0087g of Er2O3, and 0.0178g of Yb2O3 respectively, mix them evenly, and grind them thoroughly for 30min;

[0081] S2: Add 15g of B2O3 and 0.2395g of Sr(NO3)2 to the material ground in S1 and mix thoroughly. The amount of B2O3 added is 7.5 times the mass of Ta2O5, and the molar ratio of B2O3 to Sr(NO3)2 added is 1:0.0038.

[0082] S3: Sinter the well-mixed material described in S2 at 1100℃ for 18 hours;

[0083] S4: After the product sintered in S3 is filtered, it is placed in an oven and dried at 80℃ for 2 hours.

[0084] S5: The dried sample was placed in an HCl solution at pH 2 for acid washing for 6 hours, then filtered and dried in an oven at 80°C for 2 hours to obtain the luminescent material.

[0085] Example 5

[0086] Preparation of erbium-ytterbium co-doped β-Ta₂O₅ green upconversion luminescent materials by solvent molten salt method:

[0087] S1: Massager Ta 5+ :Er 3+ :Yb 3+ =2:0.0038:0.05, weigh 2g of Ta2O5, 0.0033g of Er2O3 and 0.0446g of Yb2O3 respectively, mix them evenly and grind them thoroughly for 30min;

[0088] S2: Add 15g of B2O3 and 0.2395g of Sr(NO3)2 to the material ground in S1 and mix thoroughly. The amount of B2O3 added is 7.5 times the mass of Ta2O5, and the molar ratio of B2O3 to Sr(NO3)2 added is 1:0.0038.

[0089] S3: Sinter the well-mixed material described in S2 at 1100℃ for 24 hours;

[0090] S4: After the product sintered in S3 is filtered, it is placed in an oven and dried at 80℃ for 2 hours.

[0091] S5: The dried sample was placed in an HCl solution with pH 0 for acid washing for 6 hours, then the sample was filtered and dried in an oven at 80°C for 2 hours to obtain the luminescent material.

[0092] Example 6

[0093] Preparation of erbium-ytterbium co-doped β-Ta₂O₅ green upconversion luminescent materials by solvent molten salt method:

[0094] S1: Massager Ta 5+ :Er 3+ :Yb 3+ =2:0.01:0.02, weigh 2g of Ta2O5, 0.0087g of Er2O3, and 0.0178g of Yb2O3 respectively, mix them evenly, and grind them thoroughly for 30min;

[0095] S2: Add 15g of B2O3 and 0.3831g of Sr(NO3)2 to the material ground in S1 and mix thoroughly. The amount of B2O3 added is 7.5 times the mass of Ta2O5, and the molar ratio of B2O3 to Sr(NO3)2 added is 1:0.006.

[0096] S3: Sinter the well-mixed material described in S2 at 1200℃ for 18 hours;

[0097] S4: After the product sintered in S3 is filtered, it is placed in an oven and dried at 80℃ for 2 hours.

[0098] S5: The dried sample was placed in an HCl solution with pH 0 for acid washing for 6 hours, then the sample was filtered and dried in an oven at 80°C for 2 hours to obtain the luminescent material.

[0099] The specific experimental conditions for each embodiment are shown in Table 1:

[0100] Table 1. Summary of test conditions for each embodiment.

[0101]

[0102] Experiment and Results Analysis

[0103] (1) X-ray diffraction (XRD) experiment and results

[0104] Examples 1, 2, 3, 4, 5, and 6 show different amounts of Sr(NO3)2 solvent and different amounts of Er. 3+ / Yb 3+ X-ray diffraction experiments were conducted on luminescent material samples prepared by the molten salt method with a specific content, and the results are as follows: Figure 1 As shown.

[0105] The results show that erbium-ytterbium co-doped β-Ta2O5 green upconversion luminescent material with target fluorescence intensity was successfully prepared by the molten salt method using B2O3 and Sr(NO3)2 as solvents under the preparation conditions provided in this invention.

[0106] The diffraction patterns of the luminescent material samples prepared in Examples 1, 2, 3, and 4 are compared. It can be seen that there is some B2O3 residue on the surface of the grown crystal, but it can be removed by acid washing, which further improves the purity of the sample.

[0107] A comparison of the diffraction patterns of the luminescent material samples prepared in Examples 2, 4, and 6 shows that as the Sr(NO3)2 content increases, hexagonal SrTa4O structures appear in the crystal. 11 Phase impurities.

[0108] The diffraction pattern of the luminescent material sample prepared in Example 5 shows that the luminescent material crystal grown under these conditions contains a pure β-Ta₂O₅ phase, almost no B₂O₃ residue, and only a small amount of SrTa₄O₅. 11 Phase impurities are present.

[0109] (2) Upconversion spectroscopy test and result analysis

[0110] In the spectral tests conducted on the luminescent material samples prepared in Examples 1-6 within the green upconversion wavelength range, the results (e.g.) Figures 2-4 As shown in the figures, significant differences and optimization effects were observed. Specifically, the luminescent material samples prepared in all six examples successfully exhibited green upconversion luminescence characteristics and possessed a certain fluorescence intensity, indicating that these luminescent material samples can effectively convert low-energy photons into green high-energy photons under specific excitation conditions. Among them, the luminescent material sample prepared in Example 5 showed stronger performance in green upconversion fluorescence intensity, with its fluorescence intensity significantly higher than that of the other examples. This reflects the optimization effect of Example 5 in the preparation process or formulation.

[0111] Figure 3 and Figure 4 This indicates that acid washing can further improve the fluorescence intensity of the samples. The fluorescence intensity of the samples prepared in Examples 2 and 4 after acid washing is 1.65 times and 1.82 times that of the samples prepared in Examples 1 and 3 without acid washing, respectively.

[0112] (3) Scanning electron microscopy (SEM) testing and result analysis

[0113] The luminescent material samples prepared in Examples 3, 4, and 5 were subjected to electron microscopy scanning, and SEM images were generated, as shown below. Figure 5 As shown. The results indicate that, compared to Example 3, the luminescent material sample prepared in Example 4 by adding an acid washing process was able to remove some small particles and residual B2O3 from the surface of the large crystals. Example 5, in addition to acid washing, also adjusted Er... 3+ / Yb 3+The concentration formulation resulted in a columnar crystal structure in the prepared luminescent material sample, providing a more direct transmission channel and reducing photon scattering and loss within the material, thereby significantly improving photoelectric transmission efficiency. Furthermore, the acid washing step reduced solvent residue, ensuring the purity of the prepared luminescent material sample.

[0114] (4) Analysis of 980nm laser excitation test and upconversion spectroscopy results

[0115] Under 980nm laser excitation, existing commercial NaYF4:Er 3+ / Yb 3+ The green phosphor was tested, and its fluorescence performance was compared with that of the luminescent material sample prepared in the examples. The results are shown in Table 2.

[0116] Table 2. Fluorescence intensity of each example versus commercial product NaYF4:Er 3+ / Yb 3+ percentage

[0117] Example 1 18.8 Example 2 31.1 Example 3 27.1 Example 4 49.4 Example 5 86.7 Example 6 37.9

[0118] The fluorescence integral intensity of the upconversion green light of the samples prepared in Examples 1-6 can reach that of the commercial phosphor product NaYF4:Er 3+ / Yb 3+ The percentage is over 18.8%. The upconversion fluorescence spectrum results of the sample prepared in Example 5 are as follows: Figure 6 As shown, the fluorescence integral intensity of its upconversion green light can reach that of commercial phosphor products NaYF4:Er 3+ / Yb 3+ 86.7%.

[0119] (5) Analysis of temperature-dependent upconversion spectroscopy results excited by 980nm laser

[0120] The luminescent material sample prepared in Example 5 was subjected to temperature-dependent upconversion fluorescence spectroscopy under 980 nm laser excitation, and the LIR value and relative temperature sensitivity S were further investigated. R The relationship with temperature.

[0121] Spectral test results as follows Figure 7 As shown. In the temperature range of 303 to 723 K, Er 3+ Ionic 2 H 11 / 2 → 4 I 15 / 2 , 4 S 3 / 2 → 4 I 15 / 2 and 4 F 9 / 2 → 4 I15 / 2 The emission of light from the transition decreases as the temperature increases.

[0122] The fluorescence integral intensity emitted by the transition of two thermally coupled energy levels of rare-earth ions to the ground state is only related to temperature, also known as LIR technology. The sensitivity of the LIR value to temperature determines the application prospects of fluorescent materials in the photothermal field. The relationship curve between the LIR value and temperature T of the luminescent material sample prepared in Example 5 can be calculated by the following formula:

[0123]

[0124] I H For Er 3+ of 2 H 11 / 2 → 4 I 15 / 2 Integrated intensity value of emitted fluorescence;

[0125] I S For Er 3+ of 4 S 3 / 2 → 4 I 15 / 2 Emitted fluorescence integral intensity value; B is a constant, k B It is the Boltzmann constant, and ΔE is 2 H 11 / 2 and 4 S 3 / 2 The band gap between energy levels.

[0126] The fitted function is LIR = 32.99exp(-1050.11 / T), see [link / reference]. Figure 8 This indicates that the LIR value increases with increasing temperature, showing a one-to-one correspondence and a high degree of sensitivity.

[0127] The relative temperature sensitivity S of the luminescent material sample prepared in Example 5 R The relationship curve between temperature T and temperature can be calculated using the following formula:

[0128]

[0129] The results are as follows Figure 9 As shown, the sample achieves a maximum relative temperature sensitivity of 0.01145 K at 303 K. -1 Commercially available NaYF4:Er 3+ / Yb 3+ The phosphor achieved a maximum absolute sensitivity of 0.00368 K at 363 K. -1This means that the luminescent material sample prepared in Example 5 can more accurately sense and respond to temperature changes, thereby improving the accuracy and reliability of sensing and having better application prospects in the field of photothermal sensing.

[0130] In summary, the erbium-ytterbium co-doped β-Ta₂O₅ green upconversion luminescent material prepared by this invention, using β-Ta₂O₅ as the matrix, exhibits higher chemical stability, lower toxicity, significantly enhanced green upconversion fluorescence intensity, and greater temperature sensitivity, thus improving the NaYF₄:Er 3+ / Yb 3+ Despite the instability and safety issues associated with phosphors, they hold promising application potential in specific fields such as photothermal sensing and are expected to replace commercially available NaYF4:Er. 3+ / Yb 3+ Fluorescent powder.

[0131] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing an erbium-ytterbium co-doped β-Ta₂O₅ green upconversion luminescent material, characterized in that, The luminescent material has the chemical formula β-Ta₂O₅:aEr 3+ / bYb 3+ Where a:b = 1:2~15, a = 0.003~0.01, the preparation method includes the following steps: S1: Weigh out the raw materials Ta2O5, Er2O3 and Yb2O3, mix them evenly and grind them thoroughly; S2: Add B2O3 and Sr(NO3)2 to the material ground in S1 and mix thoroughly. The amount of B2O3 added is 1.5 to 8 times the mass of Ta2O5, and the molar ratio of the amount of B2O3 to Sr(NO3)2 added is 1:0.0015 to 0.

006. S3: Sinter the well-mixed material described in S2 at 800~1200℃ for 18~30 h; S4: The product sintered in S3 is subjected to solid-liquid separation, and the solid is dried to obtain the luminescent material.

2. The preparation method of the erbium-ytterbium co-doped β-Ta₂O₅ green upconversion luminescent material according to claim 1, characterized in that, The luminescent material has the chemical formula β-Ta₂O₅:0.01Er. 3+ / 0.02Yb 3+ .

3. The preparation method of the erbium-ytterbium co-doped β-Ta₂O₅ green upconversion luminescent material according to claim 1, characterized in that, The luminescent material has the chemical formula β-Ta₂O₅:0.0038Er. 3+ / 0.05Yb 3+ .

4. The method for preparing the erbium-ytterbium co-doped β-Ta₂O₅ green upconversion luminescent material according to claim 1, characterized in that, The luminescent material obtained by drying in S4 is acid-washed in an acidic solution with a pH of 0-4 for 5-7 hours, followed by solid-liquid separation. The solid is then dried to obtain the acid-washed luminescent material.

5. The preparation method of the erbium-ytterbium co-doped β-Ta₂O₅ green upconversion luminescent material according to claim 4, characterized in that, The acid solution is an HCl solution.

6. The method for preparing the erbium-ytterbium co-doped β-Ta₂O₅ green upconversion luminescent material according to claim 1, characterized in that, The drying time is 1 to 4 hours.

7. The method for preparing the erbium-ytterbium co-doped β-Ta₂O₅ green upconversion luminescent material according to claim 1, characterized in that, The purity of Er2O3, Yb2O3 and Ta2O5 is all above 99.9%.

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