Preparation method and application of a new negative thermal expansion material
New negative thermal expansion materials doped with Yb2O3 and Nd2O3 were prepared by 808nm excitation, which solved the problems of instability of existing materials at room temperature and limited application of 980nm excitation, and realized the application of high-absorption and low-cost negative thermal expansion materials in medical and communication fields.
Patent Information
- Application Number
- CN202411065467.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-05
- Publication Date
- 2025-09-30
- Estimated Expiration
- 2044-08-05
AI Technical Summary
Existing negative thermal expansion materials are in a metastable phase at room temperature and are easily decomposed. In addition, their 980nm excitation optical applications are limited, making it difficult to achieve low-cost, widely used negative thermal expansion materials for preparation and performance control.
Using 808nm excitation light source, a new negative thermal expansion material doped with Yb2O3 and Nd2O3 was prepared. The opal template and precursor solution were sintered in an air atmosphere to form a Yb2W3O12:Nd3+ thin film, realizing the energy transfer of Nd3+→Yb3+ and significant luminescence.
The new negative thermal expansion material prepared has high absorption rate under 808nm excitation, low cost and stable performance. It can be used in the medical and communication fields to realize temperature measurement and luminescence regulation.
Smart Images
Figure CN118978181B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of inorganic non-metallic materials, and in particular to a preparation method and application of a novel negative thermal expansion material. Background Art
[0002] Most materials in nature expand when heated and contract when cooled, but the anomalous phenomenon of "heat shrinks and cold expands"—negative thermal expansion—can also occur. Differences in thermal expansion coefficients between materials can cause device fatigue, performance degradation, and even permanent failure. With technological advancements, the demand for materials with low or zero thermal expansion coefficients is increasing. Research into negative thermal expansion (NTE) materials is aimed at combining positive and negative thermal expansion materials to create zero or low thermal expansion materials. Naturally available NTE materials are very limited, and even fewer possess excellent performance and engineering application value. Currently, the urgent challenges facing NTE materials are the active search for new NTE materials and the development of effective preparation methods for unknown materials. For existing NTE materials, the pressing challenge is effective performance control, such as appropriately lowering the temperature transition point, achieving zero thermal expansion, and controlling the thermal expansion coefficient. For example, widely studied oxide negative thermal expansion materials include ZrW2O8, a common AM2O8-type material. However, ZrW2O8 is a metastable material at room temperature, undergoes a phase transition at around 150°C, and is prone to decomposition when composited with other materials, among other issues that severely restrict its application. Lanthanide ion-doped upconversion luminescence experiments (nanocrystals, thin films, etc.) feature efficient near-infrared (NIR) upconversion, low luminescence background interference, and negligible biotoxicity, and have been widely used in biological fields such as bioimaging, biosensing, and drug delivery. However, water—a vital component of living organisms—has strong absorption in the NIR spectrum around 970nm, which limits optical applications that respond to 980nm. Therefore, 808nm light excitation is used to minimize the risk of overheating.
[0003] Therefore, it is very necessary and of great significance to develop a new thin film material with stable negative expansion performance excited by 808nm, simple process, and suitable for large-scale production. Summary of the Invention
[0004] The purpose of the present invention is to design a method for preparing a new negative thermal expansion material that can convert low-energy excitation light into high-energy luminescence, produce obvious negative thermal expansion phenomenon through excitation by an 808nm excitation light source, and has good sensitivity and reversibility.
[0005] In order to achieve the above object, the present invention is implemented by the following technical solution: A method for preparing a new type of negative thermal expansion material, characterized in that it includes the following steps:
[0006] A method for preparing a novel negative thermal expansion material, characterized by comprising the following steps:
[0007] S1. Preparing an opal template: using a quartz plate as a substrate, treating the substrate, placing the treated substrate in a polystyrene sol liquid, and heating it at a constant temperature for 3 to 5 days to obtain an opal template;
[0008] S2. Prepare a precursor solution: weigh Yb2O3 and Nd2O3 in a molar ratio of Yb2O3:Nd2O3=287-574:18.3-36.6, put the weighed Yb2O3 and Nd2O3 into a beaker, then add 20-30 mL of concentrated nitric acid to the beaker, heat and dissolve to obtain a nitrate solution; heat the obtained nitrate solution to evaporate the water in the nitrate solution to obtain a gel-like mixture of Yb(NO3)3 and Nd(NO3)3; after the mixture is fully cooled, add 2-4 mL of anhydrous ethanol, stir well and let stand to obtain a clear Yb2W3O 12 :Nd 3+ Precursor solution;
[0009] S3. Use a pipette to draw 20-30 μl of Yb2W3O 12 :Nd 3+ The precursor sol is dropped onto the surface of the template and allowed to evenly penetrate into the opal template. The precursor sol is sintered in an air atmosphere at 800-900°C for 2.5-3.5 hours to obtain a new negative thermal expansion material.
[0010] Furthermore, in S1, the substrate for preparing the opal template is a quartz sheet, and the process includes the following steps:
[0011] S1.1. Prepare a polystyrene sol: Clean several 25 mm x 25 mm weighing bottles. Add 7 ml of deionized water to each cleaned bottle. Add 500 μl of a 654 bandgap monodisperse polystyrene microsphere suspension to each bottle. Ultrasonicate the solution in each bottle in an ultrasonic disperser for 1–2 h before dispersing. This yields a polystyrene sol.
[0012] S1.2, substrate cleaning: Take out several quartz pieces and soak them in a mixed solution of concentrated sulfuric acid and hydrogen peroxide for 1-2 hours to clean the surface and perform surface activation treatment. Then, rinse the residual acid on the surface with clean water until the pH is neutral. Finally, rinse and soak with deionized water to obtain the substrate;
[0013] S1.3. Remove the substrates soaked in S1.2 one by one and insert them vertically along the wall of the volumetric flask into the polystyrene sol liquid, inserting 2 to 4 substrates symmetrically into each flask.
[0014] S1.4. Place the volumetric flask containing the quartz plate obtained in S1.3 in an electric thermostat at 50-60°C for 3-5 days to obtain the opal template.
[0015] Another object of the present invention is to provide an application of a new type of negative thermal expansion material, characterized in that the new type of negative thermal expansion material is used in the fields of medical treatment and communications.
[0016] Furthermore, the novel negative thermal expansion material is applied in the medical and communication fields, specifically in temperature sensors and integrated circuits;
[0017] The application principle is: the new negative thermal expansion material can achieve Nd 3+ →Yb 3+ The energy transfer enables the new negative thermal expansion material to emit significant light in the near-infrared range.
[0018] The beneficial effects of the present invention are:
[0019] The present invention prepares a new type of negative thermal expansion material film. Compared with the negative thermal expansion material excited at 980nm, the negative thermal expansion material excited at 808nm has a higher absorption rate, a wider application and a lower cost. At the same time, the synthesis method of the new negative thermal expansion material has good repeatability and reliability. It can be used to adjust the Nd 3+ The luminescence of ions is regulated; the present invention has low cost and is expected to be applied in the fields of medical treatment, communication, etc., and is expected to achieve industrial production. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.
[0021] Figure 1 This is an XRD image of the new negative thermal expansion material prepared in Example 1 of the present invention;
[0022] Figure 2 This is a picture of the structure of the opal template prepared in Example 1 of the present invention;
[0023] Figure 3 This is a structural diagram of the new negative thermal expansion material prepared in Example 1 of the present invention;
[0024] Figure 4 This is a spectrum picture of the new negative thermal expansion material prepared in Example 1 of the present invention under 808nm laser irradiation.
[0025] Figure 5 This is a temperature-varying spectrum image of the new negative thermal expansion material prepared in Example 1 of the present invention under 808nm laser irradiation.
[0026] Figure 6 This is a temperature sensitivity diagram of the new negative thermal expansion material prepared in Example 1 of the present invention at 20-300°C under 808nm laser irradiation. DETAILED DESCRIPTION
[0027] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.
[0028] Example 1
[0029] This embodiment describes a specific preparation method of a new type of negative thermal expansion material, and the steps are as follows:
[0030] S1. Preparation of opal template:
[0031] S1.1. Prepare a polystyrene sol: Clean several 25 mm x 25 mm weighing bottles. Add 7 ml of deionized water to each cleaned bottle. Add 500 μl of a 654 bandgap monodisperse polystyrene microsphere suspension to each bottle. Ultrasonicate the solution in each bottle in an ultrasonic disperser for 1–2 h before dispersing. This yields a polystyrene sol.
[0032] S1.2, substrate cleaning: Take out several quartz pieces and soak them in a mixed solution of concentrated sulfuric acid and hydrogen peroxide for 2 hours to clean the surface and perform surface activation treatment. Then, rinse the residual acid on the surface with clean water until the pH is neutral. Finally, rinse and soak with deionized water to obtain the substrate;
[0033] S1.3. Remove the substrates soaked in S1.2 one by one and insert them vertically along the wall of the volumetric flask into the polystyrene sol liquid, inserting three substrates symmetrically into each flask.
[0034] S1.4. Place the volumetric flask containing the quartz plate obtained in S1.3 in an electric thermostat at 55°C for 3 to 5 days to obtain the opal template.
[0035] S2. Preparation of precursor solution:
[0036] Weighed Yb2O3 (m = 2.8g) and Nd2O3 (m = 0.2g) were placed in a beaker (the molar ratio of Yb2O3 to Nd2O3 was 287:18.3), and then 20mL of concentrated nitric acid was added to the beaker and heated to dissolve to obtain a nitrate solution; the obtained nitrate solution was heated to evaporate the water in the nitrate solution to obtain a gel-like mixture of Yb(NO3)3 and Nd(NO3)3; after the mixture was fully cooled, 2mL of anhydrous ethanol was added, and the mixture was fully stirred and allowed to stand to obtain a clear Yb2W3O 12 :Nd 3+ Precursor solution;
[0037] S3. Use a pipette to draw 30 μl of Yb2W3O 12 :Nd 3+ The precursor sol is dropped onto the template surface and allowed to evenly penetrate into the opal template. The new negative thermal expansion material is obtained by sintering it in air at 850°C for 3 hours.
[0038] Example 2
[0039] This example describes the specific application of the new negative thermal expansion material prepared in Example 1, as follows:
[0040] The new negative thermal expansion material was placed at the 808 nm semiconductor laser irradiation position and irradiated with an 808 nm semiconductor laser (steady-state / transient fluorescence spectrometer (Edinburgh FLS1000)); Figure 3 The results show that the new negative thermal expansion material prepared by the present invention can achieve Nd under 808nm laser irradiation. 3+ →Yb 3+ The energy transfer of the new negative thermal expansion material enables it to emit light significantly in the near-infrared range; the thermal enhancement of the new negative thermal expansion material is attributed to Yb2W3O 12 The lattice shrinkage of Nd 3+ To Yb 3+ The energy transfer of ions is increased and phonons are assisted, with good reversibility. Under 808nm excitation, Nd 3+ The typical emission spectrum of ions can be controlled.
[0041] The specific application principle of temperature measurement in the fields of medical care and communications is as follows:
[0042] The negative thermal expansion material film Yb2W3O prepared 12 :Nd 3+ Application as temperature measurement:
[0043] The negative thermal expansion material phosphor Yb2W3O 12 :Nd3+ The sample was heated at 20℃, 60℃, 100℃, 140℃, 180℃, 220℃, 260℃ and 300℃, and the fluorescence spectrum shown in the figure was obtained by using FLS980 steady-state / transient fluorescence spectrometer. It can be seen from the spectrum that the near-infrared (975nm, 1058nm, 1330nm) gradually increases with increasing temperature, indicating that the fluorescence intensity is dependent on temperature. Therefore, we can measure temperature through the relationship between fluorescence intensity and temperature.
[0044] The absolute temperature sensitivity Sr is used to express the rate of change of the FIR value with temperature:
[0045]
[0046] The sensitivity first increases and then decreases with the increase of temperature, such as Figure 6 The sensitivity is temperature-dependent, reaching a maximum absolute sensitivity of 0.6% K at 573 K. -1 , which proves the feasibility of temperature measurement.
Claims
1. A method for preparing a new negative thermal expansion material, characterized in that: The steps include: S1. Preparing an opal template: using a quartz plate as a substrate, treating the substrate, placing the treated substrate in a polystyrene sol liquid, and heating it at a constant temperature for 3 to 5 days to obtain an opal template; S2. Prepare a precursor solution: weigh Yb2O3 and Nd2O3 in a molar ratio of Yb2O3:Nd2O3=287-574:18.3-36.6, put the weighed Yb2O3 and Nd2O3 into a beaker, then add 20-30 mL of concentrated nitric acid to the beaker, heat and dissolve to obtain a nitrate solution; heat the obtained nitrate solution to evaporate the water in the nitrate solution to obtain a gel-like mixture of Yb(NO3)3 and Nd(NO3)3; after the mixture is fully cooled, add 2-4 mL of anhydrous ethanol, stir well and let stand to obtain a clear Yb2W3O 12 :Nd 3+ Precursor solution; S3. Use a pipette to draw 20-30 μl of Yb2W3O 12 :Nd 3+ The precursor sol is dropped onto the surface of the template and allowed to evenly penetrate into the opal template. The precursor sol is sintered in an air atmosphere at 800-900°C for 2.5-3.5 hours to obtain a new negative thermal expansion material.
2. The method for preparing a novel negative thermal expansion material according to claim 1, characterized in that: In S1, the substrate for preparing the opal template is a quartz sheet, which includes the following steps: S1.
1. Prepare a polystyrene sol: Clean several 25 mm x 25 mm weighing bottles. Add 7 ml of deionized water to each cleaned bottle. Add 500 μl of a 654 bandgap monodisperse polystyrene microsphere suspension to each bottle. Ultrasonicate the solution in each bottle in an ultrasonic disperser for 1–2 h before dispersing. This yields a polystyrene sol. S1.2, substrate cleaning: Take out several quartz pieces and soak them in a mixed solution of concentrated sulfuric acid and hydrogen peroxide for 1-2 hours to clean the surface and perform surface activation treatment. Then, rinse the residual acid on the surface with clean water until the pH is neutral. Finally, rinse and soak with deionized water to obtain the substrate; S1.
3. Remove the substrates soaked in S1.2 one by one and insert them vertically along the wall of the volumetric flask into the polystyrene sol liquid, inserting 2 to 4 substrates symmetrically into each flask. S1.
4. Place the volumetric flask containing the quartz plate obtained in S1.3 in an electric thermostat at 50-60°C for 3-5 days to obtain the opal template.
3. Application of the new negative thermal expansion material prepared according to the preparation method of claim 1 in the fields of medicine and communications.
4. The use according to claim 3, characterized in that Application of the novel negative thermal expansion material in the medical and communications fields, specifically in temperature sensors and integrated circuits; The application principle is: the new negative thermal expansion material can achieve Nd 3+ →Yb 3+ The energy transfer enables the new negative thermal expansion material to emit significant light in the near-infrared range.