A SiO2-coated negative thermal expansion film and its application
By coating Yb2W3O12:Nd3+ with a negative thermal expansion film using SiO2, the problem of luminescence quenching due to heat was solved, the near-infrared luminescence intensity was enhanced, and the temperature sensing sensitivity was improved, thus achieving more accurate temperature measurement.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- KUNMING UNIV OF SCI & TECH
- Filing Date
- 2024-12-12
- Publication Date
- 2026-05-29
AI Technical Summary
Existing negative thermal expansion materials suffer from poor performance in temperature display applications due to the quenching phenomenon of light emission and heat generation, and their temperature sensing is not sensitive enough.
A negative thermal expansion film of Yb2W3O12:Nd3+ was coated with SiO2. Impurities were avoided during the preparation process by the sol-gel method. The luminescence performance and temperature sensing sensitivity were enhanced by using opal template and SiO2 coating.
Without affecting the luminescence performance, the near-infrared luminescence intensity of the Yb2W3O12:Nd3+ film was significantly enhanced, and the temperature sensing sensitivity was improved, enabling more accurate temperature measurement.
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Figure CN119735380B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of temperature measurement technology, specifically relating to a SiO2-coated negative thermal expansion film and its application. Background Technology
[0002] Negative thermal expansion films are materials whose volume decreases with increasing temperature, a phenomenon opposite to the positive thermal expansion (i.e., volume increases with increasing temperature) of most materials. Negative thermal expansion materials are valuable in engineering and technical applications because they can compensate for the positive thermal expansion of other materials, thereby improving structural stability and precision. Negative thermal expansion is usually related to the crystal structure of a material, particularly when atoms or molecules in the material exhibit nonlinear or asymmetric vibrational modes in response to temperature changes. However, most phosphors currently based on negative thermal expansion materials often face the phenomenon of luminescence quenching due to heat, reducing their application in temperature displays. Summary of the Invention
[0003] To address the shortcomings of the prior art, this invention provides a SiO2-coated negative thermal expansion film and its application.
[0004] To achieve the above objectives, the technical solution adopted by the present invention is: a SiO2-coated negative thermal expansion film, which is a SiO2-coated Yb2W3O film. 12 :Nd 3+ A negative thermal expansion film is loaded onto an opal template;
[0005] The method for preparing the SiO2-coated negative thermal expansion film includes the following steps:
[0006] (1) (NH4)6H2W 12 O 40 XH2O added to water forms WO3 solution;
[0007] (2) Add concentrated nitric acid to Yb₂O₃ and Nd₂O₃, then heat to evaporate the water to obtain a gel-like mixture of Yb(NO₃)₃ and Nd(NO₃)₃. Then add anhydrous ethanol and stir, followed by the addition of WO₃ solution to obtain Yb₂W₃O₃. 12 :Nd 3+ Precursor solution;
[0008] (3) Yb2W3O 12 :Nd 3+ The precursor solution was dropped onto an opal template and then sintered to obtain a negative thermal expansion film.
[0009] (4) Mix tetraethyl orthosilicate and ethanol and stir to obtain SiO2 solution;
[0010] (5) Then the SiO2 solution is dropped onto the negative thermal expansion film and left to stand, and then sintered to obtain the SiO2-coated negative thermal expansion film.
[0011] This invention uses the sol-gel method with nitric acid to obtain gel-like Yb(NO3)3 and Nd(NO3)3, which can directly react with WO3, avoiding the generation of Yb2W3O when Yb(NO3)3 and Nd(NO3)3 are dissolved in WO3 solution. 12 :Nd 3+ Other impurities in the precursor significantly reduce the luminescence intensity and temperature sensitivity of the final SiO2-coated negative thermal expansion film.
[0012] As a preferred embodiment of the present invention, the Yb2O3, Nd2O3 and (NH4)6H2W 12 O 40 The mass ratio of XH2O is 2.8568:0.122:5.3574.
[0013] In a preferred embodiment of the present invention, the mass ratio of tetraethyl orthosilicate to ethanol is 0.20833:7.89.
[0014] As a preferred embodiment of the present invention, the SiO2-coated negative thermal expansion film contains Yb2W3O 12 :Nd 3+ The mass ratio of SiO2 to SiO2 is 0.06:0.025.
[0015] As a preferred embodiment of the present invention, the method for preparing the opal template includes:
[0016] S1: Add monodisperse polystyrene microsphere suspension to water and sonicate to obtain polystyrene sol liquid;
[0017] S2: Immerse the quartz sheet in a mixed solution of concentrated sulfuric acid and hydrogen peroxide, then rinse off the residual acid on the surface with water until the pH is neutral, and finally wash and soak with water to obtain the substrate.
[0018] S3: Insert the substrate vertically into the polystyrene sol liquid and place it at 50-60℃ for 3-5 days to obtain the opal template.
[0019] This invention also claims protection for the application of the SiO2-coated negative thermal expansion film in temperature measurement.
[0020] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention uses the negative thermal expansion material Yb2W3O 12 :Nd 3+ As a matrix, by coating with SiO2, the luminescence of the Yb2W3O film is achieved without affecting the negative thermal expansion film. 12 :Nd3+ The near-infrared luminescence of the film is significantly enhanced. Furthermore, compared to negative thermal expansion material films without SiO2 coating, the negative thermal expansion material film described in this invention is more sensitive to temperature. Attached Figure Description
[0021] Figure 1 The fluorescence spectra of the negative thermal expansion material film prepared in Comparative Example 1, under 808 nm laser excitation, were measured by a steady-state / transient fluorescence spectrometer at temperatures of 20℃, 60℃, 100℃, 140℃, 180℃, 220℃, 260℃, and 300℃.
[0022] Figure 2 The fluorescence spectra of the SiO2-coated negative thermal expansion film prepared in Example 1 under 808nm laser excitation at temperatures of 20℃, 60℃, 100℃, 140℃, 180℃, 220℃, 260℃, and 300℃ are measured by a steady-state / transient fluorescence spectrometer.
[0023] Figure 3 The graph shows the relationship between the sensitivity of the SiO2-coated negative thermal expansion film prepared in Example 1 and temperature.
[0024] Figure 4 For Example 1 and Comparative Example 1, under 808nm laser excitation, I at various identical temperatures 1058nm The graph shows a comparison of the emission peak intensities. In the graph, the SiO2-coated negative thermal expansion film at 1050 nm is the SiO2-coated negative thermal expansion film prepared in Example 1, and the negative thermal expansion film at 1050 nm is the film prepared in Comparative Example 1. Detailed Implementation
[0025] To better illustrate the purpose, technical solution, and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.
[0026] Methods for preparing opal templates include:
[0027] S1.1 Preparation of polystyrene sol liquid: Clean several 25mm×25mm weighing bottles, add 7ml of deionized water to each clean weighing bottle, then drop 500μl of 654 bandgap monodisperse polystyrene microsphere suspension into each weighing bottle, and finally place the solution in each weighing bottle into an ultrasonic disperser for ultrasonic dispersion. After ultrasonic dispersion for 1-2 hours, take it out to obtain polystyrene sol liquid.
[0028] S1.2, Substrate cleaning: Take out several quartz sheets and immerse them in a mixed solution of concentrated sulfuric acid and hydrogen peroxide for 2 hours for surface cleaning and surface activation treatment. Then rinse off the residual acid on the surface with water until the pH is neutral. Finally, rinse and immerse with deionized water to obtain the substrate.
[0029] S1.3. Take out the substrates soaked in S1.2 one by one and insert them vertically into the polystyrene sol liquid along the wall of the volumetric flask, inserting 3 substrates symmetrically into each flask.
[0030] S1.4 Place the volumetric flask containing the quartz plate obtained in S1.3 into an electric thermostatic oven at 55°C for 3-5 days to obtain the opal template.
[0031] Example 1
[0032] A method for preparing a SiO2-coated negative thermal expansion thin film includes the following steps:
[0033] (1) 5.3574g of (NH4)6H2W 12 O 40 XH2O is added to 3 mL of water to form a WO3 solution.
[0034] (2) 2.8568 g Yb₂O₃ and 0.122 g Nd₂O₃ were added to 20 mL of concentrated nitric acid, and then heated to evaporate the water to obtain a gel-like mixture of Yb(NO₃)₃ and Nd(NO₃)₃. Then, 2 mL of anhydrous ethanol was added and stirred, followed by the addition of WO₃ solution to obtain Yb₂W₃O₃. 12 :Nd 3+ Precursor solution.
[0035] (3) Add 30 microliters of Yb2W3O 12 :Nd 3+ The precursor solution was dropped onto an opal template and then sintered at 850°C for 3 hours in air to obtain a negative thermal expansion film.
[0036] (4) Mix 0.20833g of tetraethyl orthosilicate and 7.89g of ethanol and stir to obtain a SiO2 solution.
[0037] (5) Then, 30 μL of SiO2 solution was dropped onto the negative thermal expansion film and left to stand for 1 hour. The film was then sintered in air at 300°C for 6 hours to obtain the SiO2-coated negative thermal expansion film.
[0038] Example 2
[0039] A method for preparing a SiO2-coated negative thermal expansion thin film includes the following steps:
[0040] (1) 5.3574g of (NH4)6H2W 12 O 40 XH2O is added to 3 mL of water to form a WO3 solution.
[0041] (2) 2.8568 g Yb₂O₃ and 0.122 g Nd₂O₃ were added to 20 mL of concentrated nitric acid, and then heated to evaporate the water to obtain a gel-like mixture of Yb(NO₃)₃ and Nd(NO₃)₃. Then, 2 mL of anhydrous ethanol was added and stirred, followed by the addition of WO₃ solution to obtain Yb₂W₃O₃. 12 :Nd 3+ Precursor solution.
[0042] (3) Add 30 microliters of Yb2W3O 12 :Nd 3+ The precursor solution was dropped onto an opal template and then sintered at 800°C for 3.5 hours in air to obtain a negative thermal expansion film.
[0043] (4) Mix 0.20833g of tetraethyl orthosilicate and 7.89g of ethanol and stir to obtain a SiO2 solution.
[0044] (5) Then, 30 μL of SiO2 solution was dropped onto the negative thermal expansion film and left to stand for 1 hour. The film was then sintered in air at 400°C for 6 hours to obtain the SiO2-coated negative thermal expansion film.
[0045] Example 3
[0046] A method for preparing a SiO2-coated negative thermal expansion thin film includes the following steps:
[0047] (1) 5.3574g of (NH4)6H2W 12 O 40 XH2O is added to 3 mL of water to form a WO3 solution.
[0048] (2) 2.8568 g Yb₂O₃ and 0.122 g Nd₂O₃ were added to 20 mL of concentrated nitric acid, and then heated to evaporate the water to obtain a gel-like mixture of Yb(NO₃)₃ and Nd(NO₃)₃. Then, 2 mL of anhydrous ethanol was added and stirred, followed by the addition of WO₃ solution to obtain Yb₂W₃O₃. 12 :Nd 3+ Precursor solution.
[0049] (3) Add 30 microliters of Yb2W3O 12 :Nd 3+ The precursor solution was dropped onto an opal template and then sintered at 900°C for 2.5 hours in air to obtain a negative thermal expansion film.
[0050] (4) Mix 0.20833g of tetraethyl orthosilicate and 7.89g of ethanol and stir to obtain a SiO2 solution.
[0051] (5) Then, 30 μL of SiO2 solution was dropped onto the negative thermal expansion film and left to stand for 1 hour. The film was then sintered in air at 350°C for 6 hours to obtain the SiO2-coated negative thermal expansion film.
[0052] Comparative Example 1
[0053] A method for preparing a negative thermal expansion film includes the following steps:
[0054] (1) 5.3574g of (NH4)6H2W 12 O 40 XH2O is added to 3 mL of water to form a WO3 solution.
[0055] (2) 2.8568 g Yb₂O₃ and 0.122 g Nd₂O₃ were added to 20 mL of concentrated nitric acid, and then heated to evaporate the water to obtain a gel-like mixture of Yb(NO₃)₃ and Nd(NO₃)₃. Then, 2 mL of anhydrous ethanol was added and stirred, followed by the addition of WO₃ solution to obtain Yb₂W₃O₃. 12 :Nd 3+ Precursor solution.
[0056] (3) Add 30 microliters of Yb2W3O 12 :Nd 3+ The precursor solution was dropped onto an opal template and then sintered at 850°C for 3 hours in air to obtain a negative thermal expansion film.
[0057] Comparative Example 2
[0058] A method for preparing a SiO2-coated negative thermal expansion thin film includes the following steps:
[0059] (1) 5.3574g of (NH4)6H2W 12 O 40 XH2O is added to 3 mL of water to form a WO3 solution.
[0060] (2) 2.8568 g Yb₂O₃ and 0.122 g Nd₂O₃ were added to 20 mL of concentrated nitric acid, and then heated to evaporate the water to obtain a gel-like mixture of Yb(NO₃)₃ and Nd(NO₃)₃. Then, 2 mL of anhydrous ethanol was added and stirred, followed by the addition of WO₃ solution to obtain Yb₂W₃O₃. 12 :Nd 3+ Precursor solution.
[0061] (3) Mix 0.20833g of tetraethyl orthosilicate and 7.89g of ethanol and stir to obtain a SiO2 solution.
[0062] (4) Yb2W3O 12 :Nd 3+The precursor solution and SiO2 solution were mixed, and 60 μL of the solution was dropped onto an opal template. Then, the mixture was sintered at 450 °C for 3 hours in air to obtain a SiO2-coated negative thermal expansion film.
[0063] This comparative example will use Yb2W3O 12 :Nd 3+ When the precursor solution and SiO2 solution are mixed, a precipitate is formed, and this precipitate is not SiO2-coated Yb2W3O. 12 :Nd 3+ It is not a material with negative thermal expansion, but other impurities, and it does not emit light at room temperature under an 808nm excitation source.
[0064] Example of effect 1
[0065] Test samples: the materials prepared in Example 1 and the materials prepared in Comparative Examples 1-2.
[0066] Test method: Application of the prepared negative thermal expansion material film for temperature measurement:
[0067] (1) Using 808nm light excitation, the test sample was heated to 20℃, 60℃, 100℃, 140℃, 180℃, 220℃, 260℃, or 300℃, and the results were obtained using an FLS980 steady-state / transient fluorescence spectrometer. Figure 1 , 2 The fluorescence spectrum shown can be used to obtain the relationship between fluorescence intensity and temperature.
[0068] (2) Temperature is estimated by the relationship between fluorescence intensity and temperature.
[0069] according to Figure 1 and Figure 2 It can be seen that the uncoated SiO2 negative thermal expansion film of Comparative Example 1 showed little change in near-infrared (975nm, 1058nm, and 1330nm) fluorescence intensity when heated to 20℃, 60℃, 100℃, 140℃, 180℃, 220℃, 260℃, or 300℃. The SiO2-coated negative thermal expansion film prepared in Example 1 showed a gradual increase in near-infrared (975nm, 1058nm, and 1330nm) fluorescence intensity with increasing temperature, indicating that the fluorescence intensity is temperature-dependent, suggesting that SiO2 coating increases the Yb2W3O content. 12 :Nd 3+ The near-infrared luminescence intensity of the negative thermal expansion film can be measured, and the temperature can be estimated based on the relationship between fluorescence intensity and temperature.
[0070] The relationship between the fluorescence intensity and temperature of the material prepared in Example 1 is as follows: Where C1 = 0.31 and C2 = 3.32.
[0071] The absolute temperature sensitivity Sr of a material is used to represent the rate of change of the FIR (temperature-dependent spectral) value with temperature T:
[0072]
[0073] In the formula, C1 and C2 are constants, and I 975 I represents the intensity of the sample at the 975nm emission peak. 1058 The value represents the intensity of the sample at the emission peak at 1058 nm.
[0074] Sensitivity decreases as temperature increases, such as Figure 3 It exhibits temperature dependence, reaching its maximum absolute sensitivity of 0.06% K at 293 K. -1 This demonstrates the feasibility of temperature measurement. The maximum absolute sensitivity of the uncoated SiO2 material in Comparative Example 1 is approximately 0.004% K. -1 The reading of around 100 indicates that the material without SiO2 coating is not sensitive to temperature, meaning its sensitivity is too low to accurately estimate the temperature. Figure 4 This also illustrates the SiO2-coated Yb2W3O prepared in the examples. 12 :Nd 3+ Negative thermal expansion films are more sensitive to temperature, while the Yb2W3O prepared in Comparative Example 1... 12 :Nd 3+ Negative thermal expansion films are not highly sensitive to materials.
[0075] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.
Claims
1. A SiO2-coated negative thermal expansion film, characterized in that, SiO2 coating Yb2W3O 12 Nd 3+ A negative thermal expansion film is loaded onto an opal template; The method for preparing the SiO2-coated negative thermal expansion thin film includes the following steps: (1) (NH4)6H2W 12 O 40 XH2O added to water forms WO3 solution; (2) Add concentrated nitric acid to Yb2O3 and Nd2O3, then heat to evaporate the water to obtain a gel-like mixture of Yb(NO3)3 and Nd(NO3)3. Then add anhydrous ethanol and stir, followed by the addition of WO3 solution to obtain Yb2W3O 12 Nd 3+ Precursor solution; (3) Yb2W3O 12 Nd 3+ The precursor solution was dropped onto an opal template and then sintered to obtain a negative thermal expansion film. (4) Mix tetraethyl orthosilicate and ethanol and stir to obtain a SiO2 solution; (5) Then the SiO2 solution is dropped onto the negative thermal expansion film and left to stand, and then sintered to obtain the SiO2-coated negative thermal expansion film; The Yb2O3, Nd2O3 and (NH4)6H2W 12 O 40 The mass ratio of XH2O is 2.8568:0.122:5.3574; The SiO2-coated negative thermal expansion film contains Yb2W3O 12 Nd 3+ The mass ratio of SiO2 to SiO2 is 0.06:0.
025.
2. The SiO2-coated negative thermal expansion film as described in claim 1, characterized in that, The mass ratio of tetraethyl orthosilicate to ethanol is 0.20833:7.
89.
3. The SiO2-coated negative thermal expansion film as described in claim 1, characterized in that, The method for preparing the opal template includes: S1: Add monodisperse polystyrene microsphere suspension to water and sonicate to obtain polystyrene sol liquid; S2: Immerse the quartz sheet in a mixed solution of concentrated sulfuric acid and hydrogen peroxide, then rinse off the residual acid on the surface with water until the pH is neutral, and finally wash and soak with water to obtain the substrate. S3: Insert the substrate vertically into the polystyrene sol liquid and place it at 50~60℃ for 3~5 days to obtain the opal template.
4. The application of the SiO2-coated negative thermal expansion film according to any one of claims 1-3 in temperature measurement, characterized in that, Temperature is estimated by measuring the relationship between fluorescence intensity and temperature.
5. The application of the SiO2-coated negative thermal expansion film as described in claim 4 in temperature measurement, characterized in that, The relationship between fluorescence intensity and temperature is as follows: C1 and C2 are constants, I 975 I represents the intensity of the SiO2-coated negative thermal expansion film at the 975nm emission peak. 1058 The intensity of the SiO2-coated negative thermal expansion film at the 1058 nm emission peak is given by T, where T is the temperature.