SiO2 coated negative thermal expansion film and application thereof

Abstract

The invention discloses a SiO2 coated negative thermal expansion film and application thereof, and belongs to the technical field of temperature measurement. The preparation method comprises the following steps: dropwise adding a Yb2W3O12: Nd < 3 + > precursor solution on an opal template, calcining to obtain a negative thermal expansion film, dropwise adding a SiO2 solution on the negative thermal expansion film, calcining to obtain the SiO2 coated negative thermal expansion film of which the SiO2 coated Yb2W3O12: Nd < 3 + > negative thermal expansion film is loaded on the opal template. According to the invention, the negative thermal expansion material Yb2W3O12: Nd < 3 + > is used as a matrix, and the near-infrared luminescence of the Yb2W3O12: Nd < 3 + > film is obviously enhanced by coating SiO2 on the premise of not influencing the luminescence of the negative thermal expansion film. In addition, compared with a negative thermal expansion material film which is not coated with SiO2, the negative thermal expansion material film disclosed by the invention is more sensitive to temperature induction.

Description

Technical Field

[0001] The invention belongs to the technical field of temperature measurement, and in particular relates to a SiO2 coated negative thermal expansion film and application thereof. Background Art

[0002] Negative thermal expansion film is a material that decreases in volume when the temperature rises, which is the opposite of the positive thermal expansion of most materials (i.e., the volume increases when the temperature rises). Negative thermal expansion materials are of great value in engineering and technological applications because they can be used to compensate for the positive thermal expansion of other materials, thereby improving the stability and precision of the structure. Negative thermal expansion is usually related to the crystal structure of the material, especially when the atoms or molecules in the material exhibit nonlinear or asymmetric vibration modes when the temperature changes. However, most of the current phosphors based on negative thermal expansion materials often face the phenomenon of luminescence and heat quenching, which reduces the application of the material in temperature display. Summary of the invention

[0003] In view of the above-mentioned shortcomings of the prior art, the present invention provides a SiO2 coated negative thermal expansion film and application thereof.

[0004] To achieve the above purpose, the technical solution adopted by the present invention is: a SiO2 coated negative thermal expansion film, which is SiO2 coated Yb2W3O 12 :Nd 3+ Negative thermal expansion films are supported on opal templates;

[0005] The method for preparing the SiO2 coated negative thermal expansion film comprises the following steps:

[0006] (1) (NH4)6H2W 12 O 40 .XH2O is added to water to form WO3 solution;

[0007] (2) Add Yb2O3 and Nd2O3 to concentrated nitric acid, then heat and evaporate the water to obtain a gelatinous mixture of Yb(NO3)3 and Nd(NO3)3. Then add anhydrous ethanol and stir, then add WO3 solution to obtain Yb2W3O 12 :Nd 3+ Precursor solution;

[0008] (3) Yb2W3O 12 :Nd 3+ The precursor solution was dropped onto the opal template and then sintered to obtain a negative thermal expansion film;

[0009] (4) mixing ethyl orthosilicate and ethanol and stirring to obtain a SiO2 solution;

[0010] (5) Then, the SiO2 solution is dropped onto the negative thermal expansion film and allowed to stand, and then sintered to obtain the SiO2 coated negative thermal expansion film.

[0011] The present invention uses the sol-gel method to add nitric acid to obtain gel-like Yb(NO3)3 and Nd(NO3)3, which can directly react with WO3, avoiding the direct use of Yb(NO3)3 and Nd(NO3)3 to dissolve in WO3 solution to produce Yb2W3O 12 :Nd 3+ Other impurities outside 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] As 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 Yb2W3O in the SiO2-coated negative thermal expansion film 12 :Nd 3+ The mass ratio of SiO2 is 0.06:0.025.

[0015] As a preferred embodiment of the present invention, the method for preparing the opal template comprises:

[0016] S1: adding a monodisperse polystyrene microsphere suspension into water and ultrasonically obtaining a polystyrene sol liquid;

[0017] S2: Soak the quartz plate in a mixed solution of concentrated sulfuric acid and hydrogen peroxide, then rinse the residual acid on the surface with clean water until the pH is neutral, and finally wash and soak with water to obtain a substrate;

[0018] S3: insert the substrate vertically into the polystyrene sol liquid and place it at 50-60° C. for 3-5 days to obtain the opal template.

[0019] The present invention also claims to protect the application of the SiO2 coated negative thermal expansion film in temperature measurement.

[0020] Compared with the prior art, the invention has the following beneficial effects: the invention uses the negative thermal expansion material Yb2W3O 12 :Nd 3+ As a matrix, Yb2W3O is coated with SiO2 without affecting the luminescence of the negative thermal expansion film. 12 :Nd3+ The film's luminescence in the near infrared is significantly enhanced. In addition, compared with the negative thermal expansion material film not coated with SiO2, the negative thermal expansion material film of the present invention is more sensitive to temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a fluorescence spectra of the negative thermal expansion material film prepared in Comparative Example 1 measured by a steady-state / transient fluorescence spectrometer at 20°C, 60°C, 100°C, 140°C, 180°C, 220°C, 260°C, and 300°C under 808nm laser excitation.

[0022] Figure 2 This is a fluorescence spectra of the SiO2-coated negative thermal expansion film prepared in Example 1 measured by a steady-state / transient fluorescence spectrometer under 808nm laser excitation at temperatures of 20°C, 60°C, 100°C, 140°C, 180°C, 220°C, 260°C, and 300°C.

[0023] Figure 3 This is a graph showing the relationship between the sensitivity of the SiO2 coated negative thermal expansion film prepared in Example 1 and the temperature.

[0024] Figure 4 The I of Example 1 and Comparative Example 1 at the same temperature under 808nm laser excitation 1058nm The comparison chart of the peak intensity of luminescence. In the figure, the SiO2 coated 1050nm is the SiO2 coated negative thermal expansion film prepared in Example 1, and 1050nm is the negative thermal expansion film prepared in Comparative Example 1. DETAILED DESCRIPTION

[0025] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0026] A method for preparing an opal template, comprising:

[0027] S1.1. Preparation of polystyrene sol liquid: clean several 25 mm × 25 mm weighing bottles, add 7 ml of deionized water to each cleaned weighing bottle, then drop 500 μl of 654 band gap monodisperse polystyrene microsphere suspension into each weighing bottle, finally place the solution in each weighing bottle in an ultrasonic disperser for ultrasonic dispersion, take out after ultrasonic dispersion for 1 to 2 hours to obtain polystyrene sol liquid.

[0028] S1.2, substrate cleaning: take out several quartz plates and soak them in a mixed solution of concentrated sulfuric acid and hydrogen peroxide for 2 hours to perform surface cleaning and surface activation treatment, then rinse the residual acid on the surface with clean water until the pH is neutral, and finally wash and soak with deionized water to obtain the substrate.

[0029] S1.3. Take out the substrates soaked in S1.2 piece by piece, and vertically insert them into the polystyrene sol liquid along the wall of the volumetric flask, with 3 pieces inserted symmetrically into each flask.

[0030] S1.4. Place the volumetric flask containing the quartz plate obtained in S1.3 into an electric thermostatic box at 55°C for 3 to 5 days to obtain the opal template.

[0031] Example 1

[0032] A method for preparing a SiO2 coated negative thermal expansion film comprises the following steps:

[0033] (1) 5.3574 g (NH4)6H2W 12 O 40 .XH2O is added to 3mL of water to form WO3 solution.

[0034] (2) Add 2.8568 g Yb2O3 and 0.122 g Nd2O3 to 20 mL concentrated nitric acid, and then heat to evaporate the water to obtain a gelatinous mixture of Yb(NO3)3 and Nd(NO3)3. Then add 2 mL of anhydrous ethanol and stir, and then add WO3 solution to obtain Yb2W3O 12 :Nd 3+ Precursor solution.

[0035] (3) 30 μl Yb2W3O 12 :Nd 3+ The precursor solution was dropped onto the opal template and then sintered at 850 °C for 3 h in air atmosphere to obtain a negative thermal expansion film.

[0036] (4) 0.20833 g of ethyl orthosilicate and 7.89 g of ethanol were mixed and stirred to obtain a SiO2 solution.

[0037] (5) Then, 30 μl of SiO2 solution was dropped onto the negative thermal expansion film and allowed to stand for 1 hour. The film was sintered at 300°C in an air atmosphere for 6 hours to obtain a SiO2 coated negative thermal expansion film.

[0038] Example 2

[0039] A method for preparing a SiO2 coated negative thermal expansion film comprises the following steps:

[0040] (1) 5.3574 g (NH4)6H2W 12 O 40 .XH2O is added to 3mL of water to form WO3 solution.

[0041] (2) Add 2.8568 g Yb2O3 and 0.122 g Nd2O3 to 20 mL concentrated nitric acid, and then heat to evaporate the water to obtain a gelatinous mixture of Yb(NO3)3 and Nd(NO3)3. Then add 2 mL of anhydrous ethanol and stir, and then add WO3 solution to obtain Yb2W3O 12 :Nd 3+ Precursor solution.

[0042] (3) 30 μl Yb2W3O 12 :Nd 3+ The precursor solution was dropped onto the opal template and then sintered at 800 °C for 3.5 h in air atmosphere to obtain a negative thermal expansion film.

[0043] (4) 0.20833 g of ethyl orthosilicate and 7.89 g of ethanol were mixed and stirred to obtain a SiO2 solution.

[0044] (5) Then, 30 μl of SiO2 solution was dropped onto the negative thermal expansion film and allowed to stand for 1 hour. The film was sintered at 400°C in an air atmosphere for 6 hours to obtain a SiO2 coated negative thermal expansion film.

[0045] Example 3

[0046] A method for preparing a SiO2 coated negative thermal expansion film comprises the following steps:

[0047] (1) 5.3574 g (NH4)6H2W 12 O 40 .XH2O is added to 3mL of water to form WO3 solution.

[0048] (2) Add 2.8568 g Yb2O3 and 0.122 g Nd2O3 to 20 mL concentrated nitric acid, and then heat to evaporate the water to obtain a gelatinous mixture of Yb(NO3)3 and Nd(NO3)3. Then add 2 mL of anhydrous ethanol and stir, and then add WO3 solution to obtain Yb2W3O 12 :Nd 3+ Precursor solution.

[0049] (3) 30 μl Yb2W3O 12 :Nd 3+ The precursor solution was dropped onto the opal template and then sintered at 900 °C for 2.5 h in air atmosphere to obtain a negative thermal expansion film.

[0050] (4) 0.20833 g of ethyl orthosilicate and 7.89 g of ethanol were mixed and stirred to obtain a SiO2 solution.

[0051] (5) Then, 30 μl of SiO2 solution was dropped onto the negative thermal expansion film and allowed to stand for 1 hour. The film was sintered at 350°C in an air atmosphere for 6 hours to obtain a SiO2 coated negative thermal expansion film.

[0052] Comparative Example 1

[0053] A method for preparing a negative thermal expansion film comprises the following steps:

[0054] (1) 5.3574 g (NH4)6H2W 12 O 40 .XH2O is added to 3mL of water to form WO3 solution.

[0055] (2) Add 2.8568 g Yb2O3 and 0.122 g Nd2O3 to 20 mL concentrated nitric acid, and then heat to evaporate the water to obtain a gelatinous mixture of Yb(NO3)3 and Nd(NO3)3. Then add 2 mL of anhydrous ethanol and stir, and then add WO3 solution to obtain Yb2W3O 12 :Nd 3+ Precursor solution.

[0056] (3) 30 μl Yb2W3O 12 :Nd 3+ The precursor solution was dropped onto the opal template and then sintered at 850 °C for 3 h in air atmosphere to obtain a negative thermal expansion film.

[0057] Comparative Example 2

[0058] A method for preparing a SiO2 coated negative thermal expansion film comprises the following steps:

[0059] (1) 5.3574 g (NH4)6H2W 12 O 40 .XH2O is added to 3mL of water to form WO3 solution.

[0060] (2) Add 2.8568 g Yb2O3 and 0.122 g Nd2O3 to 20 mL concentrated nitric acid, and then heat to evaporate the water to obtain a gelatinous mixture of Yb(NO3)3 and Nd(NO3)3. Then add 2 mL of anhydrous ethanol and stir, and then add WO3 solution to obtain Yb2W3O 12 :Nd 3+ Precursor solution.

[0061] (3) 0.20833 g of ethyl orthosilicate and 7.89 g of ethanol were mixed and stirred to obtain a SiO2 solution.

[0062] (4) Yb2W3O 12 :Nd 3+The precursor solution and SiO2 solution were mixed, 60 μl of the solution was dropped on the opal template, and then sintered at 450°C for 3 hours in an air atmosphere to obtain a SiO2-coated negative thermal expansion film.

[0063] In this comparative example, Yb2W3O 12 :Nd 3+ When the precursor solution and SiO2 solution are mixed, a precipitate will be generated, and the precipitate is not SiO2-coated Yb2W3O 12 :Nd 3+ Negative thermal expansion materials are not other impurities, and at room temperature, no luminescence will occur under an 808nm excitation light source.

[0064] Effect Example 1

[0065] Test samples: the material 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 as temperature measurement:

[0067] (1) Using 808 nm light excitation, the test sample was heated at 20°C, 60°C, 100°C, 140°C, 180°C, 220°C, 260°C or 300°C, and the following results were obtained using the FLS980 steady-state / transient fluorescence spectrometer: Figure 1 , 2 The fluorescence spectrum shown in the figure can then be used to obtain the relationship between fluorescence intensity and temperature.

[0068] (2) Temperature is estimated based on the relationship between fluorescence intensity and temperature.

[0069] according to Figure 1 and Figure 2 It can be seen that when the negative thermal expansion film of uncoated SiO2 in Comparative Example 1 is heated at 20°C, 60°C, 100°C, 140°C, 180°C, 220°C, 260°C or 300°C, the fluorescence intensity of the near infrared (975nm, 1058nm and 1330nm) does not change much. The SiO2 coated negative thermal expansion film prepared in Example 1 gradually increases with the increase of temperature in the near infrared (975nm, 1058nm and 1330nm), indicating that the fluorescence intensity is temperature-dependent, indicating that SiO2 coating increases the Yb2W3O 12 :Nd 3+ The luminescence intensity of the negative thermal expansion film in the near infrared can be used to estimate the temperature based on the relationship between the fluorescence intensity and temperature.

[0070] The relationship between the fluorescence intensity and temperature of the material prepared in Example 1 is: Among them, C1=0.31 and C2=3.32.

[0071] The absolute temperature sensitivity Sr of the material is used to express the rate of change of the FIR (variable temperature spectrum) value with temperature T:

[0072]

[0073] Where C1 and C2 are constants, I 975 is the intensity of the sample at the 975nm emission peak, I 1058 is the intensity of the sample at the luminescence peak of 1058 nm.

[0074] The sensitivity decreases with increasing temperature, such as Figure 3 It shows a temperature dependence and reaches a maximum absolute sensitivity of 0.06% K at 293 K. -1 , proving the feasibility of temperature measurement. The maximum absolute sensitivity of the uncoated SiO2 material in Comparative Example 1 is about 0.004% K -1 This indicates that the material not coated with SiO2 is not sensitive to temperature, that is, the sensitivity is too low to achieve accurate estimation of temperature. Figure 4 It also illustrates the SiO2-coated Yb2W3O prepared in the embodiment 12 :Nd 3+ The negative thermal expansion film is more sensitive to temperature, and the Yb2W3O prepared in Comparative Example 1 12 :Nd 3+ Negative thermal expansion films are not very material sensitive.

[0075] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A SiO2 coated negative thermal expansion film, characterized in that: Yb2W3O coated with SiO2 12 :Nd 3+ Negative thermal expansion films are supported on opal templates; The method for preparing the SiO2 coated negative thermal expansion film comprises the following steps: (1) (NH4)6H2W 12 O 40 .XH2O is added to water to form WO3 solution; (2) Add Yb2O3 and Nd2O3 to concentrated nitric acid, then heat and evaporate the water to obtain a gelatinous mixture of Yb(NO3)3 and Nd(NO3)3. Then add anhydrous ethanol and stir, then add WO3 solution to obtain Yb2W3O 12 :Nd 3+ Precursor solution; (3) Yb2W3O 12 :Nd 3+ The precursor solution was dropped onto the opal template and then sintered to obtain a negative thermal expansion film; (4) mixing ethyl orthosilicate and ethanol and stirring to obtain a SiO2 solution; (5) Then, the SiO2 solution is dropped onto the negative thermal expansion film and allowed to stand, and then sintered to obtain the SiO2 coated negative thermal expansion film.

2. The SiO2 coated negative thermal expansion film according to claim 1, characterized in that: The Yb2O3, Nd2O3 and (NH4)6H2W 12 O 40 The mass ratio of .XH2O is 2.8568:0.122:5.3574.

3. The SiO2 coated negative thermal expansion film according to claim 1, characterized in that: The mass ratio of tetraethyl orthosilicate to ethanol is 0.20833:7.

89.

4. The SiO2 coated negative thermal expansion film according to claim 1, characterized in that: The SiO2 coated negative thermal expansion film contains Yb2W3O 12 :Nd 3+ The mass ratio of SiO2 is 0.06:0.

025.

5. The SiO2 coated negative thermal expansion film according to claim 1, characterized in that: The method for preparing the opal template comprises: S1: adding a monodisperse polystyrene microsphere suspension into water and ultrasonically obtaining a polystyrene sol liquid; S2: Soak the quartz plate in a mixed solution of concentrated sulfuric acid and hydrogen peroxide, then rinse the residual acid on the surface with clean water until the pH is neutral, and finally wash and soak with water to obtain a substrate; S3: insert the substrate vertically into the polystyrene sol liquid and place it at 50-60° C. for 3-5 days to obtain the opal template.

6. Application of the SiO2 coated negative thermal expansion film in temperature measurement as claimed in any one of claims 1 to 5, characterized in that: The temperature is estimated based on the relationship between fluorescence intensity and temperature.

7. The application of the SiO2 coated negative thermal expansion film in temperature measurement as claimed in claim 6, characterized in that: The relationship between the fluorescence intensity and temperature is: C1, C2 are constants, I 975 is the intensity of the SiO2 coated negative thermal expansion film at the 975nm luminescence peak, I 1058 is the intensity of the SiO2 coated negative thermal expansion film at the luminescence peak of 1058nm, and T is the temperature.

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