A high-sensitivity non-contact temperature measuring material, its preparation method and application

Abstract

This invention discloses a high-sensitivity non-contact temperature measuring material, its preparation method, and its application, belonging to the fields of materials science and crystal physics. This invention solves the problem of low sensitivity in non-contact temperature measuring materials. The chemical formula of the non-contact temperature measuring material of this invention is xat.%Yb. 3+ / yat.%Tm 3+ / zat.%Mo 6+ NaLa 1‑xat.%‑yat.% Gd 0.06 (W) 1‑zat.% / 2 O4)2 or xat.%Yb 3+ / yat.%Tm 3+ NaLa 1‑xat.%‑yat.% Gd 0.06 (WO4)2, where 2≤x≤10, 1≤y≤5, 1≤z≤5. The temperature-sensing crystal provided by this invention has high-efficiency fluorescence emission, is compatible with commercial pump sources, broadens the temperature detection range, improves the temperature sensitivity of the crystal material, and increases the application range of the temperature-sensing material in the field of non-contact temperature measurement.

Description

Technical Field

[0001] This invention belongs to the field of materials science and crystal physics, specifically relating to a high-sensitivity non-contact temperature measurement material, its preparation method, and its application. Background Technology

[0002] With the rapid development of science and technology, the objects of temperature measurement are constantly shrinking (such as the high integration and miniaturization of optoelectronic devices). Traditional temperature measurement methods, such as contact thermocouple temperature measurement, are difficult to apply at the micro-nano level due to the size limitations of their sensing devices. Furthermore, the measurement process requires heat transfer to reach thermal equilibrium, which is not only time-consuming but also alters the actual temperature of the measured object, affecting the accuracy of the temperature measurement. Therefore, there is an urgent need to develop new temperature sensors that are fast-responding, non-invasive, and possess high detection sensitivity and spatial resolution.

[0003] Traditional thermally coupled temperature measurement devices rely on heat conduction and radiation, which have limitations such as slow response speed and measurement accuracy affected by thermal inertia. In contrast, temperature measurement devices based on non-thermally coupled energy levels utilize the energy level transition characteristics of electrons or ions within a substance to detect temperature. By detecting the energy level distribution or fluorescence intensity ratio of atoms or ions at a specific temperature, no contact with the object being measured is required.

[0004] The sensitivity of non-contact temperature measurement devices based on non-thermally coupled energy levels depends on their internal sensing materials. Crystal materials can achieve non-contact temperature measurement through laser excitation and fluorescence detection, improving the safety and durability of temperature sensors. Among non-contact temperature sensor materials, tungstate crystals have become a research hotspot due to their excellent optical and thermal properties. Compared with other non-contact temperature measurement device materials (such as semiconductors, metal oxides, and polymers), tungstate crystal materials have rich energy level structures and thermosensitive optical properties, especially when doped with rare earth ions (Tm). 3+ Subsequently, its fluorescence intensity ratio (FIR) becomes sensitive to temperature changes. This energy level transition characteristic enables the crystal to achieve a measurement range from low to high temperatures. However, in practical applications, Tm... 3+ Ion-doped tungstate crystals have drawbacks as a material for non-contact temperature measurement devices in many high-precision applications: one is due to Tm 3+ First, the absorption band of ions does not match the emission wavelength range of commercially available laser diodes, and the lack of suitable pump sources leads to high costs. Second, the probability of non-radiative electronic relaxation in rare-earth upconversion luminescent materials increases significantly at high temperatures, causing fluorescence thermal quenching and affecting the luminescence intensity at high temperatures. This makes the fluorescence signal used for temperature detection difficult to detect, thus limiting the temperature measurement sensitivity of the probe and resulting in low measurement sensitivity. Therefore, current non-contact temperature sensor materials based on non-thermally coupled energy levels still suffer from sensitivity limitations. Summary of the Invention

[0005] To address the problem of low sensitivity in current non-contact temperature sensing materials based on non-thermal coupling energy levels, this invention provides a high-sensitivity non-contact temperature sensing material, its preparation method, and its applications.

[0006] To solve the above-mentioned technical problems, the present invention is achieved through the following technical solution:

[0007] One objective of this invention is to provide a highly sensitive non-contact temperature sensing material, the chemical formula of which is x at.% Yb. 3+ / y at.%Tm 3+ / z at.%Mo 6+ NaLa 1-x at.% -y at.% Gd 0.06 (W) 1-z at.% / 2 O4)2; x is Yb 3+ The atomic percentage, taking 2≤x≤10, y is Tm 3+ The atomic percentage, taking 1 ≤ y ≤ 5, z is Mo 6+ The percentage of atoms, where 1 ≤ z ≤ 5.

[0008] The second objective of this invention is to provide a method for preparing the above-mentioned temperature-measuring material, the method comprising:

[0009] (1) Weigh out seven raw materials, namely Na2CO3, Gd2O3, La2O3, WO3, Yb2O3, MoO3 and Tm2O3, according to the atomic percentage of each element in the general chemical formula of the thermometric material for one of the purposes;

[0010] (2) Grind the seven raw materials to obtain a mixed powder;

[0011] (3) Sinter the mixed powder, and then press the sintered material into a columnar solid to obtain polycrystalline material;

[0012] (4) The polycrystalline material is grown by the Czochralski method to obtain the temperature measuring material.

[0013] Further specifying, the grinding time in (2) is 5~8 h.

[0014] Further specified, (3) the sintering temperature is 850 ℃ and the time is 12~24 h.

[0015] Further defining the process in (4), the Czochralski process is as follows: First, place the polycrystalline material in the crucible, select the seed crystal, adjust the concentricity of the coil, the heat preservation system, the seed crystal rod, the quartz cylinder and the platinum crucible, then turn on the Czochralski furnace, heat until the polycrystalline material is completely melted and the melt flow line is stable, then slowly lower the seed crystal to contact the melt surface, perform the necking process, and then perform shoulder expansion, equal diameter growth, tailing and cooling annealing.

[0016] Furthermore, the pulling speed during the shoulder formation stage is 0.5~1.0 mm / h, and the crystal rotation speed is 10~15 rpm; the pulling speed during the constant diameter growth stage is 1.0~2.0 mm / h, and the rotation speed is 10~15 rpm; the pulling speed during the finishing stage is 1.0~2.0 mm / h, the rotation speed is 10~15 rpm, and the heating rate is 5℃ / h.

[0017] Furthermore, the cooling annealing stage is further specified: first, the temperature is reduced from the pull-out temperature to 1000 ℃ in 32 hours, then reduced from 1000 ℃ to 800 ℃ in 20 hours, then reduced from 800 ℃ to 500 ℃ in 24 hours, and finally reduced from 500 ℃ to room temperature in 20 hours.

[0018] The third objective of this invention is to provide a highly sensitive non-contact temperature sensing material, the chemical formula of which is x at.% Yb. 3+ / y at.%Tm 3+ NaLa 1-x at.% -y at.% Gd 0.06 (WO4)2; x is Yb 3+ The atomic percentage, taking 2≤x≤10, y is Tm 3+ The percentage of atoms, where 1 ≤ y ≤ 5.

[0019] The fourth objective of this invention is to provide a method for preparing the temperature-sensitive material described in the third objective above, the method comprising:

[0020] (1) Weigh out six raw materials, namely Na2CO3, Gd2O3, La2O3, WO3, Yb2O3 and Tm2O3, according to the atomic percentage of each element in the general chemical formula of the thermometric material for the purpose of the third item;

[0021] (2) Grind the six raw materials to obtain a mixed powder;

[0022] (3) The mixed powder is pressed into a columnar solid and then sintered to obtain a polycrystalline material;

[0023] (4) The polycrystalline material is grown by the Czochralski method to obtain the temperature measuring material.

[0024] Further specifying, the grinding time in (2) is 5~8 h.

[0025] Further specified, (3) the sintering temperature is 850 ℃ and the time is 12~24 h.

[0026] Further defining the process in (4), the Czochralski process is as follows: First, place the polycrystalline material in the crucible, select the seed crystal, adjust the concentricity of the coil, the heat preservation system, the seed crystal rod, the quartz cylinder and the platinum crucible, then turn on the Czochralski furnace, heat until the polycrystalline material is completely melted and the melt flow line is stable, then slowly lower the seed crystal to contact the melt surface, perform the necking process, and then perform shoulder expansion, equal diameter growth, tailing and cooling annealing.

[0027] Furthermore, the pulling speed during the shoulder formation stage is 0.5~1.0 mm / h, and the crystal rotation speed is 10~15 rpm; the pulling speed during the constant diameter growth stage is 1.0~2.0 mm / h, and the rotation speed is 10~15 rpm; the pulling speed during the finishing stage is 1.0~2.0 mm / h, the rotation speed is 10~15 rpm, and the heating rate is 5℃ / h.

[0028] Furthermore, the cooling annealing stage is further specified: first, the temperature is reduced from the pull-out temperature to 1000 ℃ in 32 hours, then reduced from 1000 ℃ to 800 ℃ in 20 hours, then reduced from 800 ℃ to 500 ℃ in 24 hours, and finally reduced from 500 ℃ to room temperature in 20 hours.

[0029] The fifth objective of this invention is to provide an application of a high-sensitivity temperature measuring material for one or three of the above objectives, specifically for use in the field of non-contact temperature measurement.

[0030] The beneficial effects of this invention are as follows:

[0031] This invention utilizes a high-temperature solid-state method and a Czochralski method to grow high-sensitivity thermometric crystal materials Yb / Tm:NLGW and Yb / Tm / Mo:NLGW. The crystals of this invention exhibit non-thermally coupled energy levels. By introducing Mo into the Yb / Tm:NLGW crystal, this invention further increases the temperature detection sensitivity and detection range, and optimizes the thermal stability of the crystal element. Compared with existing technologies, this invention also has the following advantages:

[0032] (1) In the high-sensitivity thermometric crystal materials Yb / Tm:NLGW and Yb / Tm / Mo:NLGW provided by the present invention, Tm 3+ The doping concentration is 1~5 at.%, which ensures that the crystal has high-efficiency fluorescence emission; in addition, sensitizing ions Yb are introduced into all thermometric materials. 3+ And Yb 3+The doping concentrations are all 2~10 at.%, a range that not only matches the crystals to commercial pump sources but also broadens the detection range of non-thermally coupled energy levels, improves the temperature sensitivity of the crystal material, and expands the application range of Yb / Tm:NLGW and Yb / Tm / Mo:NLGW crystals in non-contact temperature measurement devices. Further improvements in Yb... 3+ The doping concentration in the thermometric material of this invention will exacerbate nonradiative transitions, and the exacerbation of nonradiative transitions will reduce Tm. 3+ The effective fluorescence emission intensity is reduced, resulting in a weakened fluorescence intensity ratio (FIR) signal, which worsens the temperature-dependent fluorescence response, affects the accuracy and sensitivity of temperature measurement, and also reduces the temperature detection range.

[0033] (2) In this invention, Mo is introduced into Yb / Tm:NLGW crystal to obtain Yb / Tm / Mo:NLGW crystal. The Mo doping concentration is 1~5 at.%. The introduction of Mo improves the crystal's resistance to thermal quenching and reduces the crystal's coefficient of thermal expansion to solve the thermal effect problem when this crystal material is used in components. This is because the introduction of Mo allows the crystal to have a higher fluorescence intensity ratio at high temperatures, increasing the temperature detection sensitivity. At the same time, the introduction of Mo increases the polar and rigid bonds of the original NLGW matrix crystal, reducing the crystal's coefficient of thermal expansion and optimizing the performance of components prepared with this crystal at high temperatures.

[0034] (3) The Yb / Tm / Mo:NLGW crystal of the present invention is obtained through Yb 3+ Sensitized Tm 3+ Furthermore, a synergistic modification strategy to regulate the Mo-O lattice structure improved the non-contact temperature measurement performance of rare-earth-doped tungstate crystals. Yb 3+ Its broad-spectrum near-infrared absorption characteristics effectively solve the problem of traditional Tm 3+ The wavelength mismatch between doped crystal materials and commercial laser sources is addressed by achieving low-cost pumping through a highly efficient interion-ion energy transfer mechanism. Meanwhile, Mo lattice substitution of W enhances the crystal's thermal stability and suppresses fluorescence thermal quenching at high temperatures. The synergistic effect of these two strategies not only significantly expands the temperature measurement range of Yb / Tm / Mo:NLGW crystal materials but also further enhances the fluorescence signal intensity and temperature response sensitivity in the high-temperature region, providing an efficient material system for accurate real-time thermal field monitoring under extreme conditions.

[0035] (4) The present invention uses the Czochralski method to grow high-sensitivity temperature measuring materials. By controlling the growth parameters (temperature, rotation speed and pulling speed) and optimizing the crystal growth conditions, large-size, low-defect, and high crystal integrity crystal materials are grown to meet the needs of industrial production.

[0036] (5) This invention utilizes COMSOL software to perform three-dimensional spatial modeling of the furnace body used for Yb / Tm / Mo:NLGW crystal growth, and simulates the dynamic coupling effect between the internal temperature field of the crucible and the crystal microstructure within the furnace body. By simulating the viscoelastic behavior of the crystal melt before and after the introduction of Mo, it was found that the crystal melt flow rate is significantly increased after Mo doping, and the internal temperature field of the crucible is more uniform, directly enhancing the thermal convection efficiency of the melt and suppressing lattice asymmetric thermal vibration. This control mechanism enables the Yb / Tm / Mo:NLGW crystal to obtain excellent thermal stability and reduces the crystal's thermal expansion coefficient. In addition, this control mechanism ensures that the Yb / Tm / Mo:NLGW crystal of this invention does not experience a decrease in thermal performance due to changes in the matrix substrate, unlike traditional tungstate crystals, thus breaking the constraint relationship between thermal stability and heat dissipation performance in traditional tungstate crystal systems.

[0037] (6) The high-sensitivity temperature measuring material of the present invention can be applied to non-contact temperature monitoring components, so that the components have a wide temperature detection range and high sensitivity, and the components can replace thermocouples for real-time temperature monitoring. Attached Figure Description

[0038] Figure 1 X-ray diffraction patterns and X-ray rocking curves of the crystals prepared in Examples 1 and 2 of this invention are shown. (a) XRD patterns of Yb / Tm:NLGW and Yb / Tm / Mo:NLGW crystals; (b) X-ray rocking curve of Yb / Tm:NLGW crystal; (c) X-ray rocking curve of Yb / Tm / Mo:NLGW crystal.

[0039] Figure 2 The near-infrared emission spectra of the crystals prepared in Examples 1 and 2 are shown.

[0040] Figure 3 The deformation versus temperature curves of the crystals prepared in Examples 1 and 2 are shown.

[0041] Figure 4 The diagram shows a two-dimensional axisymmetric physical model of the single crystal growth furnace constructed in Examples 1 and 2, and a temperature grid diagram simulating the melt viscosity change during crystal growth. (a) Schematic diagram of the two-dimensional axisymmetric physical model of the single crystal growth furnace, (b) Schematic diagram of the complete single crystal furnace body simulation after parameter setting, (c) Yb / Tm: melt flow velocity distribution cloud map of NLGW crystal, (d) Yb / Tm / Mo: melt flow velocity distribution cloud map of NLGW crystal, (e) Yb / Tm: melt temperature and temperature gradient line of NLGW crystal, (f) Yb / Tm / Mo: melt temperature and temperature gradient line of NLGW crystal;

[0042] Figure 5 Different Tm samples prepared in Examples 1, 3-63+ Comparison of near-infrared emission spectra of Yb / Tm doping concentration and NLGW crystals;

[0043] Figure 6 The Tm content in the Yb / Tm:NLGW crystals prepared in Examples 1 and 7-10 3+ Emission peak intensity varies with Yb 3+ Comparison of near-infrared emission spectra with varying doping concentrations;

[0044] Figure 7 This is a schematic diagram of the non-contact temperature measuring device in Application Example 1;

[0045] Figure 8 The fluorescence spectra of the Yb / Tm:NLGW crystal in Application Example 1 at different temperatures;

[0046] Figure 9 The fluorescence spectra of the Yb / Tm / Mo:NLGW crystal in Application Example 1 at different temperatures;

[0047] Figure 10 For example 1, the fluorescence intensity ratio and absolute sensitivity (S) of the Yb / Tm:NLGW crystal are used. a ) and relative sensitivity (S r );

[0048] Figure 11 To apply the fluorescence intensity ratio and absolute sensitivity (S) of the Yb / Tm / Mo:NLGW crystal in Example 1 a ) and relative sensitivity (S r );

[0049] In the diagram, 1-induction coil, 2-tray, 3-glass sleeve, 4-zirconium felt and zirconium sand, 5-afterheater, 6-top ring, 7-platinum crucible. Detailed Implementation

[0050] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification.

[0051] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0052] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0053] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, the materials, reagents, methods, and instruments used are all conventional materials, reagents, methods, and instruments in the art, and can be obtained commercially by those skilled in the art.

[0054] In the following examples, Na2CO3 (4N), Gd2O3 (5N), La2O3 (5N), WO3 (5N), Yb2O3 (5N), Tm2O3 (5N), and MoO3 (4N) are used. The 4N and 5N in the above compounds represent purity, with 4N representing a purity ≥99.99% and 5N representing a purity ≥99.999%. Crystal growth was performed using a DJL-400 single crystal furnace.

[0055] Example 1

[0056] A highly sensitive temperature sensing material with the chemical formula 6 at.% Yb 3+ / 4 at.% Tm 3+ NaLa 0.90 Gd 0.06 (WO4)2.

[0057] The preparation method of this material includes the following steps:

[0058] (1) Weigh out Na2CO3, Gd2O3, La2O3, WO3, Yb2O3 and Tm2O3 according to the atomic percentage of each element in the chemical formula of the thermometric material, and dry the six raw materials at 200 °C for 24 h;

[0059] (2) Put the six raw materials into a mixer and grind them for 24 hours to ensure thorough and uniform mixing to obtain a mixed powder;

[0060] (3) The mixed powder is placed in a latex bag and sealed. It is then pressed into a columnar shape under a pressure of 200 MPa and placed in a muffle furnace and heated to 850 °C for 24 h to form a polycrystalline material.

[0061] (4) Place the polycrystalline material in a platinum crucible with a diameter of 60 mm × 58 mm × 50 mm, using NaLa(WO4)2 with the (004) crystal face as the seed crystal, and adjust the concentricity of the coil, the heat preservation system, the seed crystal rod, the quartz tube and the platinum crucible.

[0062] (5) Turn on the medium frequency induction crystal pulling furnace and start the heating system in the furnace. When the polycrystalline material in the platinum crucible is completely melted at a melting temperature of 1236 °C and the melt flow lines are clear and stable, slowly lower the seed crystal. After the seed crystal contacts the surface of the melt, perform the necking process. The heating rate during the necking process is 1 °C / h, which reduces the diameter of the seed crystal by 3 mm.

[0063] (6) Shoulder formation: Control the pulling rate to 0.5~1.0 mm / h, the crystal rotation speed to 10~15 rpm, and the cooling rate to 0.5℃ / h. When the size of the shoulder reaches the target size Φ20~22 mm, keep the temperature constant at 1230 ℃. (7) Equal diameter growth: Keep the pulling rate to 1.0~2.0 mm / h, the crystal rotation speed to 10~15 rpm, and the heating rate to 1 ℃ / h. Keep the heating rate, pulling rate, and crystal rotation speed constant during the equal diameter growth process. When the equal diameter of the crystal reaches Φ28~31 mm, the temperature is 1242~1270 ℃, and the finishing stage begins. (8) Finishing: The finishing stage is the opposite of shoulder formation. In order to ensure the integrity of the crystal, the temperature is gradually increased, and finally the pulling speed and rotation speed are reduced to 0. After the finishing length of the crystal is 5~8 mm, the crystal growth ends. Control the pulling rate to 1.0~2.0 mm / h and the crystal rotation speed to 10~15 rpm. Gradually increase the temperature to 1267~1310 ℃ at a rate of 5 ℃ / h. The crystal is then pulled out, and pulling and rotation are stopped.

[0064] (9) Cooling annealing: First, the temperature was cooled from the pull-out temperature to 1000 ℃ over 32 h, then from 1000 ℃ to 800 ℃ over 20 h, then from 800 ℃ to 500 ℃ over 24 h, and finally from 500 ℃ to room temperature over 20 h to obtain 6 at.% Yb 3+ / 4 at.% Tm 3+ NaLa 0.90 Gd 0.06 (WO4)2 crystal, i.e. Yb / Tm:NLGW crystal.

[0065] The X-ray diffraction curve of the product prepared in this embodiment is shown in the figure. Figure 1 (a) Compared with the standard card (PDF#79-1118), the positions of the product diffraction peaks match those on the card, indicating that this embodiment successfully grew 6 at.% Yb. 3+ / 4 at.% Tm 3+ NaLa 0.90 Gd 0.06 (WO4)2 crystals. In addition, the XRD curves show sharp and high intensity, indicating that the grown crystals have high crystallinity, small distortion and high phase purity. Figure 1 (b) is 6 at.% Yb3+ / 4 at.% Tm 3+ NaLa 0.90 Gd 0.06 The XRC curve of the (WO4)2 crystal shows that the diffraction peaks of the crystal in this embodiment are sharp and very narrow, with good symmetry and FWHM (half-width at half maximum) = 0.0453°. There are no twins, indicating that the crystal prepared in this embodiment is a high-quality single crystal.

[0066] The near-infrared emission spectrum of the crystal prepared in this embodiment is shown in the figure. Figure 2 .

[0067] Example 2

[0068] A highly sensitive temperature sensing material with the chemical formula 6 at.% Yb 3+ / 4 at.% Tm 3+ / 2 at.% Mo 6+ NaLa 0.90 Gd 0.06 (W) 0.99 O4)2.

[0069] The preparation method of this material includes the following steps:

[0070] (1) Weigh out Na2CO3, Gd2O3, La2O3, WO3, Yb2O3, MoO3 and Tm2O3 according to the atomic percentage of each element in the chemical formula of the thermometric material, and dry the seven raw materials at 200 °C for 24 h;

[0071] (2) Put the seven raw materials into a mixer and grind them for 24 hours to ensure thorough and uniform mixing and obtain a mixed powder;

[0072] The processes (3) to (9) are the same as the process steps (3) to (9) in Example 1, and the parameter settings are the same, resulting in 6 at.%Yb. 3+ / 4 at.% Tm 3+ / 2 at.% Mo 6+ NaLa 0.90 Gd 0.06 (W) 0.99 O4)2 crystal, i.e. Yb / Tm / Mo:NLGW crystal.

[0073] The X-ray diffraction curve of the product prepared in this embodiment is shown in the figure. Figure 1 (a) Compared with the standard card (PDF#79-1118), the positions of the product diffraction peaks match those on the card, indicating that this embodiment successfully grew 6 at.% Yb. 3+ / 4 at.% Tm 3+ / 2 at.% Mo 6+ NaLa0.90 Gd 0.06 (W) 0.99 O4)2 crystals. In addition, the XRD curves show sharp and high intensity, indicating that the grown crystals have high crystallinity, small distortion and high phase purity. Figure 1 (c) is 6 at.% Yb 3+ / 4 at.% Tm 3+ / 2 at.% Mo 6+ NaLa 0.90 Gd 0.06 (W) 0.99 The XRC curve of O4)2 crystal shows that the diffraction peaks of the crystal in this embodiment are sharp and very narrow, with good symmetry and FWHM (full width at half maximum) = 0.0403°. There are no twins, indicating that the crystal prepared in this embodiment is a high-quality single crystal.

[0074] The near-infrared emission spectrum of the crystal prepared in this embodiment is shown in the figure. Figure 2 Both crystals prepared in Examples 1 and 2 exhibit an emission peak within the detection range, located at 1796 nm, corresponding to Tm. 3+ of 3 F4→ 3 The H6 energy level transition process. Compared with Yb / Tm:NLGW crystal, with the increase of Mo... 6+ The introduction of [a substance] did not change the position and shape of the crystal emission peak, but the luminescence intensity changed significantly. For example... Figure 2 As shown in the curve, the fluorescence intensity of the Yb / Tm / Mo:NLGW crystal is 4.21 times that of the Yb / Tm:NLGW crystal. Increased luminescence intensity can significantly improve sensitivity by enhancing the signal-to-noise ratio, and it also lowers the temperature detection limit. Furthermore, increased luminescence intensity can reduce environmental noise interference, enabling more stable capture of weak signals.

[0075] Figure 3 This is a graph showing the deformation along the a-axis of the crystal structure of the products prepared in Examples 1 and 2 within the range of 300~800 K, as a function of temperature. The slope of the curve is the coefficient of thermal expansion α. l Yb / Tm: The coefficient of thermal expansion of NLGW crystal along the a-axis is 9.555 × 10⁻⁶. -6 K -1 The coefficient of thermal expansion of Yb / Tm / Mo NLGW crystal along the a-axis is 7.137 × 10⁻⁶. -6 K -1 Both types of crystals have extremely low coefficients of thermal expansion along the a-axis. This extremely low coefficient of thermal expansion can significantly suppress thermally induced deformation of the crystals and reduce the risk of thermal stress damage.

[0076] The furnace body of the DJL-400 single crystal furnace used for crystal growth in Examples 1 and 2 was modeled using COMSOL Multiphysics software, and the internal temperature field of the furnace body during crystal growth was simulated. Simulation parameters: The temperature field of the furnace body and the order of the insulation layer from the outermost layer to the crucible are: induction coil, tray, glass sleeve, zirconium felt, zirconium sand, zirconium tube, afterheater, top ring and platinum crucible.

[0077] The afterheater measures Φ91 mm × Φ45 mm × 80 mm, the annular ring measures Φ80 mm × Φ40 mm × 35 mm, and the platinum crucible (99.999% purity) measures Φ60 mm × Φ58 mm × 50 mm. The induction coil is made of double-layered brass tubing with a diameter of Φ10 mm; the outer coil measures Φ200 mm × 100 mm, the inner coil measures Φ170 mm × 140 mm, the tray measures Φ140 mm × 100 mm, the glass sleeve measures Φ120 mm × Φ110 mm × 150 mm, the zirconium felt is 2 mm thick, and the zirconium cylinder measures Φ90 mm × Φ75 mm × 97.5 mm. Considering the symmetry of the actual furnace body, the DJL-400 single crystal furnace body is simplified to a two-dimensional axisymmetric model in the simulation, and for the sake of calculation accuracy, the coil is set to 6 turns. The temperature grid diagram of the melt viscosity change inside the crucible during the simulation is shown below. Figure 4 As shown, due to the symmetrical structure inside the single crystal furnace, therefore Figure 4 (a) shows a schematic diagram of a half-crystal furnace.

[0078] like Figure 4 As shown in (c), the melt velocity field distribution within the crucible is uneven during the growth of Yb / Tm:NLGW crystals, exhibiting a significant low-velocity dead zone. Figure 4 As shown in (d), Mo-doped 6+ The melt flow rate is significantly increased, and the temperature field inside the crucible becomes more uniform. This uniform flow directly enhances the thermal convection efficiency of the melt, accelerates heat dissipation, reduces local temperature differences, suppresses lattice asymmetric thermal vibrations, and thus inhibits anisotropic thermal expansion. The melt flow rate can be further explained by the following formula:

[0079]

[0080] Where γ represents the degree of asymmetry in the atomic potential energy during lattice vibration, α is the coefficient of thermal expansion, and C ν This is the isochoric heat capacity. A homogenized temperature field makes atomic vibrations closer to simple harmonic modes, reducing the asymmetry of atomic potential energy and consequently decreasing the coefficient of thermal expansion. For example... Figure 4 (e) and Figure 4As shown in (f), the melt temperature distribution of the Yb / Tm:NLGW crystal exhibits significant spatial fluctuations, with large temperature differences between local hot and cold zones and a high curvature of the temperature gradient line. Mo is doped into the melt. 6+ Afterwards, the overall temperature field became uniform across the entire domain, indirectly verifying that... Figure 4 (d) The melt flow rate is increased. During solidification, the amplitude of temperature fluctuation decreases, eliminating stress concentration sources such as micropores and cracks in the crystal, promoting the full diffusion of Mo atoms, replacing matrix atoms to form a strong bonded structure, and thus improving the thermal properties of Yb / Tm / Mo:NLGW crystal.

[0081] Example 3

[0082] The difference between this embodiment and Embodiment 1 is that the chemical formula of the thermometric material is 6 at.% Yb. 3+ / 1 at.% Tm 3+ NaLa 0.90 Gd 0.06 (WO4)2, Tm 3+ The doping concentration was 1 at.%, and the remaining process steps and parameter settings were the same as in Example 1.

[0083] Example 4

[0084] The difference between this embodiment and Embodiment 1 is that the chemical formula of the thermometric material is 6 at.% Yb. 3+ / 2 at.% Tm 3+ NaLa 0.90 Gd 0.06 (WO4)2, Tm 3+ The doping concentration was 2 at.%, and the remaining process steps and parameter settings were the same as in Example 1.

[0085] Example 5

[0086] The difference between this embodiment and Embodiment 1 is that the chemical formula of the thermometric material is 6 at.% Yb. 3+ / 3 at.% Tm 3+ NaLa 0.90 Gd 0.06 (WO4)2, Tm 3+ The doping concentration was 3 at.%, and the remaining process steps and parameter settings were the same as in Example 1.

[0087] Example 6

[0088] The difference between this embodiment and Embodiment 1 is that the chemical formula of the thermometric material is 6 at.% Yb. 3+ / 5 at.% Tm 3+ NaLa 0.90 Gd 0.06 (WO4)2, Tm3+ The doping concentration was 5 at.%, and the remaining process steps and parameter settings were the same as in Example 1.

[0089] Near-infrared spectroscopy was performed on the crystals prepared in Examples 1 and 3-6, and the results are as follows: Figure 5 As shown, the crystal exhibits an emission peak at 1796 nm within the detection range, corresponding to Tm. 3+ of 3 F4→ 3 The H6 level transition process. With Tm 3+ With the introduction of [something], the position and shape of the crystal emission peak remain unchanged at Tm. 3+ The doping concentration reaches its maximum at 4 at.%, and then increases with Tm. 3+ As concentration increases, luminescence intensity begins to decrease. This is because, with increasing Tm... 3+ With increasing doping concentration, adjacent Tm 3+ As the spacing between ions gradually decreases, cross-relaxation (CR) occurs, which increases the Tm of adjacent ions. 3+ The effective resonant energy transfer process between ions leads to energy transfer between ions.

[0090] Example 7

[0091] The difference between this embodiment and Embodiment 1 is that the chemical formula of the thermometric material is 8 at.% Yb. 3+ / 4 at.% Tm 3+ NaLa 0.88 Gd 0.06 (WO4)2, Yb 3+ The doping concentration was 8 at.%, and the remaining process steps and parameter settings were the same as in Example 1.

[0092] Example 8

[0093] The difference between this embodiment and Embodiment 1 is that the chemical formula of the thermometric material is 10 at.% Yb. 3+ / 4 at.% Tm 3+ NaLa 0.86 Gd 0.06 (WO4)2, Yb 3+ The doping concentration was 10 at.%, and the remaining process steps and parameter settings were the same as in Example 1.

[0094] Tm in the thermometric crystal materials prepared in Examples 1 and 7-8 3+ Emission peak intensity with Yb 3+ Near-infrared test results for changes in doping concentration are shown in Figure 6 Through Yb 3+ The absorption and energy transfer mechanisms allow more energy to be used to excite Tm3 + The transition of Yb increases the luminescence efficiency and emission intensity of the crystal. However, further improvements in Yb... 3+ At ion doping concentration, such as Figure 6 Yb 3+ When the doping concentration exceeds 8 at.%, the emission spectral intensity begins to decrease, which is due to the Yb 3+ When the doping concentration exceeds the threshold, adjacent Yb 3+ Energy is transferred between impurities or quenching centers, i.e., non-radiative energy transfer, ultimately resulting in concentration quenching.

[0095] Application Example 1

[0096] The temperature-sensing crystals from Examples 1 and 2 are placed in a temperature monitoring device, the structure of which is as follows: Figure 7 As shown, a 980 nm laser diode is first connected to a Y-type silicon dioxide fiber, and the optical path is split into two segments using a wavelength division multiplexer (WDM). One segment is connected to a sapphire single-crystal fiber via a coupler. The end of the sapphire single-crystal fiber is connected to a heating stage, which consists of a heating device and a ceramic tube. The heating device is a spherical copper mold, and the entire ceramic tube is within a closed space. The closed ceramic tube is connected to the crystal, and a heater capable of raising the temperature is placed in this space, displaying parameters such as the heating temperature. The other segment is analyzed using a fiber optic spectrometer, and the data is finally read by a computer (PC).

[0097] Figure 8 and Figure 9 The fluorescence spectra of the Yb / Tm:NLGW crystal prepared in Example 1 and the Yb / Tm / Mo:NLGW crystal prepared in Example 2, respectively, under 980 nm excitation, are shown in the range of 303–483 K. It can be seen that both crystals exhibit three main fluorescence bands in the visible light wavelength range. With increasing temperature, the shape and position of the fluorescence emission spectra of both crystals remained unchanged, but the luminescence intensity gradually decreased. This decrease in fluorescence intensity is because increased temperature leads to increased lattice vibrations in the matrix material, increasing the chance of non-radiative relaxation processes, reducing ion level lifetimes, and consequently decreasing the probability of radiative transitions. Therefore, the fluorescence intensity decreases with increasing temperature.

[0098] Figure 10 (a) is the fluorescence intensity ratio of Yb / Tm:NLGW crystal. Figure 10 (b) represents the absolute sensitivity (S) of the Yb / Tm:NLGW crystal. a ) and relative sensitivity (S r ), Figure 11 (a) is the fluorescence intensity ratio of Yb / Tm / Mo:NLGW crystal. Figure 11(b) The absolute sensitivity (S) of the Yb / Tm / Mo:NLGW crystal. a ) and relative sensitivity (S r The experimental conditions were all at 980 nm (λ). ex The experiment was conducted under excitation at 980 nm. The fluorescence intensity ratio (FIR) was measured using... 690 / I 796 Calculation, Yb / Tm: Maximum absolute sensitivity of NLGW crystal (S amax ) and maximum relative sensitivity (S rmax ) are 0.085 K respectively -1 and 2.43%K -1 Yb / Tm / Mo: S of NLGW crystal amax and S rmax 0.158 K respectively -1 and 2.55%K -1 The S of two temperature-sensing materials amax and S rmax The levels are relatively high, and comparisons show that Mo doping is more effective. 6+ Then Yb / Tm: S of NLGW crystal a and S r Further improvements.

[0099] By placing the temperature-sensing material of this invention into a temperature monitoring device, the temperature-sensing crystal material of this invention can be used in various temperature monitoring scenarios. For example, it can be applied to the DJL-400 furnace body to replace thermocouples for real-time temperature monitoring. By monitoring the temperature inside the furnace body in real time, the temperature of the entire crystal growth process is made more visible, avoiding problems such as signal delays associated with traditional thermocouples.

[0100] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A high-sensitivity non-contact temperature measuring material, characterized in that, The general chemical formula of the thermometric material is x at.% Yb 3 + / y at.%Tm 3+ / z at.%Mo 6+ NaLa 1-x at.% -y at.% Gd 0.06 (W) 1-z at.% / 2 O4)2; The x is Yb 3+ The atomic percentage, taking 2≤x≤10, y is Tm 3+ The atomic percentage, taking 1 ≤ y ≤ 5, z is Mo 6+ The percentage of atoms, where 1 ≤ z ≤ 5.

2. A method for preparing the high-sensitivity non-contact temperature measuring material according to claim 1, characterized in that, The method includes: (1) Weigh out seven raw materials, namely Na2CO3, Gd2O3, La2O3, WO3, Yb2O3, MoO3 and Tm2O3, according to the atomic percentage of each element in the general chemical formula of the thermometric material; (2) Grind the seven raw materials to obtain a mixed powder; (3) Sinter the mixed powder, and then press the sintered material into a columnar solid to obtain polycrystalline material; (4) The polycrystalline material is grown by the Czochralski method to obtain the temperature measuring material.

3. A high-sensitivity non-contact temperature measuring material, characterized in that, The general chemical formula of the thermometric material is x at.% Yb 3 + / y at.%Tm 3+ NaLa 1-x at.% -y at.% Gd 0.06 (WO4)2; The x is Yb 3+ The atomic percentage, taking 2≤x≤10, y is Tm 3+ The percentage of atoms, where 1 ≤ y ≤ 5.

4. A method for preparing the high-sensitivity non-contact temperature measuring material according to claim 3, characterized in that, The method includes: (1) Weigh out six raw materials, namely Na2CO3, Gd2O3, La2O3, WO3, Yb2O3 and Tm2O3, according to the atomic percentage of each element in the general chemical formula of the thermometric material; (2) Grind the six raw materials to obtain a mixed powder; (3) Sinter the mixed powder, and then press the sintered material into a columnar solid to obtain polycrystalline material; (4) The polycrystalline material is grown by the Czochralski method to obtain the temperature measuring material.

5. The preparation method according to claim 2 or 4, characterized in that, (2) The grinding time is 5~8 h.

6. The preparation method according to claim 2 or 4, characterized in that, (3) The sintering temperature is 850 ℃ and the time is 12~24 h.

7. The preparation method according to claim 2 or 4, characterized in that, (4) The Czochralski process is as follows: First, place the polycrystalline material in the crucible, select the growth seed crystal, adjust the concentricity of the coil, the heat preservation system, the seed crystal rod, the quartz cylinder and the platinum crucible, then turn on the Czochralski furnace, heat until the polycrystalline material is completely melted and the melt flow line is stable, then slowly lower the seed crystal to contact the melt surface, perform the necking process, and then perform shoulder expansion, equal diameter growth, tailing and cooling annealing.

8. The preparation method according to claim 7, characterized in that, The pulling rate during the shoulder formation stage is 0.5~1.0 mm / h, and the crystal rotation speed is 10~15 rpm; the pulling rate during the constant diameter growth stage is 1.0~2.0 mm / h, and the rotation speed is 10~15 rpm; the pulling rate during the finishing stage is 1.0~2.0 mm / h, the rotation speed is 10~15 rpm, and the heating rate is 5 ℃ / h.

9. The preparation method according to claim 7, characterized in that, During the cooling annealing stage, the temperature was first reduced from the pull-out temperature to 1000 ℃ over 32 hours, then reduced from 1000 ℃ to 800 ℃ over 20 hours, followed by a reduction from 800 ℃ to 500 ℃ over 24 hours, and finally reduced from 500 ℃ to room temperature over 20 hours.

10. The application of a high-sensitivity non-contact temperature measuring material according to any one of claims 1 or 3, characterized in that, This temperature-measuring material is used in non-contact temperature measurement applications related to non-disease diagnosis and treatment.

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