Method for controlling symmetry of crystal field of rare earth doped oxyfluoride glass ceramics
By introducing Lu3+ ions into fluorine oxide microcrystalline glass to reduce crystal field symmetry, the problem of insufficient luminescence intensity and sensitivity of temperature sensors in harsh environments with rare earth-doped fluorine oxide microcrystalline glass is solved, achieving efficient and accurate temperature detection.
Patent Information
- Application Number
- CN202410343724.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-03-25
- Publication Date
- 2026-02-17
- Estimated Expiration
- 2044-03-25
AI Technical Summary
Existing rare-earth-doped fluoride oxide microcrystalline glass temperature sensors suffer from insufficient luminescence intensity and photothermal sensitivity in environments with strong corrosion and strong magnetic fields, making it difficult to achieve efficient and accurate temperature measurement.
By introducing optically inert rare earth ions Lu3+ with small ionic radii into the glass matrix, the local symmetry of the Y5O4F7 crystal field is reduced, and rare earth-doped fluorine-oxygen microcrystalline glass is prepared. The crystal field symmetry is then controlled to improve luminous efficiency and photothermal sensing sensitivity.
It achieves high luminous efficiency and high photothermal sensing sensitivity in complex environments, and has non-contact, high spatial resolution and fast response temperature detection capabilities. The relative photothermal sensitivity can reach 1.504% K-1 at 300K.
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Figure CN118125718B_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of rare earth doped glass ceramics, and particularly relates to a method for regulating the symmetry of a crystal field of a rare earth doped oxyfluoride glass ceramic and application thereof. BACKGROUND
[0002] The non-contact temperature sensor based on the emission of the thermal coupling energy level of rare earth ions can greatly meet the temperature detection requirements in harsh environments such as strong corrosion and strong magnetic field. In order to realize accurate temperature measurement, the required material is required to have high luminous intensity and light temperature sensitivity.
[0003] The upconversion luminescence and optical temperature sensing properties are highly dependent on the host lattice with low phonon energy, which can greatly reduce the non-radiative decay, thereby effectively improving the luminescent efficiency of the upconversion. Therefore, the rare earth ion doping is one of the key factors affecting the luminescent properties of the substrate material.
[0004] The oxyfluoride glass ceramic is an ideal substrate material for optical temperature sensing of rare earth ions due to its excellent performance. The Y5O4F7 nanocrystals with orthorhombic Vernier phase have the advantages of low phonon energy and multiple lattice sites, and are considered to be a potential optical temperature sensing material. In order to further improve the light temperature sensitivity of the material, the crystal field of the rare earth ions is regulated to obtain a low-symmetry local environment, which is beneficial to realize high emission intensity and high sensitivity. SUMMARY
[0005] In view of the deficiencies in the prior art, the present application provides a method for regulating the symmetry of a crystal field of a rare earth doped oxyfluoride glass ceramic and application thereof, which introduces an optically inert rare earth ion Lu 3+ into the glass substrate to reduce the local symmetry of the Y5O4F7 crystal field, thereby developing an oxyfluoride glass ceramic based on the regulation of the local symmetry of the crystal field of the rare earth ions. The microcrystalline glass has excellent upconversion luminescent efficiency, thermal stability and optical temperature sensing sensitivity, and has great application prospects in the preparation of high-quality optical temperature sensing materials with high luminescent efficiency, high thermal stability and high optical temperature sensing sensitivity.
[0006] The present application discloses a method for regulating the symmetry of a crystal field of a rare earth doped oxyfluoride glass ceramic, comprising:
[0007] Fluoro-oxygen microcrystalline glass raw material is mixed with ethanol and ground evenly, then subjected to high-temperature melting, pressing and molding, and annealing to obtain a precursor glass with transparent characteristics; wherein, the fluoro-oxygen microcrystalline glass raw material includes a matrix glass material and rare earth fluorides, and the rare earth fluorides include LuF3 and at least one of ErF3, YbF3, HoF3 and TmF3, that is, in addition to containing LuF3, the rare earth fluorides also include at least one of ErF3, YbF3, HoF3 and TmF3;
[0008] The precursor glass is crystallized to obtain fluorine-oxygen microcrystalline glass with rare earth ion doping.
[0009] As a further improvement of the present invention, the fluorine-oxygen microcrystalline glass raw material, by molar percentage, comprises a matrix glass material and rare earth fluorides, wherein the rare earth fluorides comprise 40-45% SiO2, 20-25% Al2O3, 15-17% Na2O, 8-12% NaF, 5-10% YF3 and 1-5% ReF3, wherein Re is Lu. 3+ And Er 3+ Yb 3+ Ho 3+ and Tm 3+ A combination of at least one of them.
[0010] As a further improvement of the present invention, the molar percentage of NaF is 8-10%, the molar percentage of YF3 is 8-10%, and the molar percentage of ReF3 is 1-3%.
[0011] As a further improvement to the present invention, Lu 3+ As an important rare earth dopant ion, it plays a role in reducing the local symmetry of rare earth ion crystal fields; its molar percentage of doping is 0.005-0.25%.
[0012] As a further improvement of the present invention, the step of mixing and grinding the fluorine-oxygen microcrystalline glass raw material with ethanol until uniform, followed by high-temperature melting, pressing and molding, and annealing, to obtain a precursor glass with transparent characteristics; includes:
[0013] Fluoro-oxygen microcrystalline glass raw materials are mixed with ethanol and ground with zirconia balls in a ball mill. After being mixed evenly, the mixture is placed in an oven to dry. The dried powder is then placed in an alumina crucible and melted at high temperature with the lid on. The molten material is pressed into sheet-like precursor glass and further transferred to a muffle furnace for annealing to obtain a precursor glass with transparent characteristics.
[0014] As a further improvement of the present invention, the grinding time is 12 hours.
[0015] As a further improvement of the present invention, the high-temperature melting temperature is 1450-1550℃ and the melting time is 1-1.5h.
[0016] As a further improvement of the present invention, the crystallization treatment of the precursor glass to obtain a fluorine-oxygen microcrystalline glass doped with rare earth ions includes:
[0017] The precursor glass is placed in a muffle furnace and heated to 650-660℃ at a heating rate of 10-20K / min and heat-treated for 1-3 hours to obtain fluorine-oxygen microcrystalline glass with rare earth ion doping.
[0018] As a further improvement of the present invention, the microcrystalline phase of the fluorine-oxygen microcrystalline glass is Y5O4F7, the crystal form is an orthorhombic Vernier phase, and the grain size is 20nm-40nm.
[0019] The present invention also discloses the application of rare earth-doped fluorine-oxygen microcrystalline glass in non-contact temperature sensor materials, wherein the rare earth-doped fluorine-oxygen microcrystalline glass is prepared by the above-mentioned method of controlling the crystal field symmetry of rare earth-doped fluorine-oxygen microcrystalline glass.
[0020] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0021] The O in Y5O4F7 nanocrystals of this invention 2- and F - The non-stoichiometry is caused by the doped rare earth ions, which provides a multi-lattice, low local symmetry rare earth ion crystal field environment, with low phonon energy, and can simultaneously achieve high upconversion luminescence and high photothermal sensing sensitivity of rare earth ions.
[0022] This invention uses doping ratio Smaller radius The lattice distortion and lattice symmetry of Y5O4F7 nanocrystals are reduced, which enhances the electro-acoustic coupling of luminescent rare earth ions and the probability of electronic transition, thereby improving the upconversion luminescence intensity.
[0023] This invention is based on rare-earth ion thermal coupling energy level fluorescence intensity ratio thermometry, which features non-contact operation, high spatial resolution and response speed, and high photothermal sensitivity. The relative photothermal sensitivity at 300K can reach 1.504% K. -1 It has significant advantages in temperature detection in complex electromagnetic fields and harsh high-temperature environments. Attached Figure Description
[0024] Figure 1 The XRD diffraction patterns of the samples in Examples 1-5 of this invention;
[0025] Figure 2 The transmittance curves of samples from Examples 1-5 of this invention are shown.
[0026] Figure 3 The emission spectra of the samples in Examples 1-5 of this invention under 980 nm excitation;
[0027] Figure 4 This is a schematic diagram showing the relationship between the relative photothermal sensitivity value (300K) and Ω2 value of the samples in Examples 1-5 of this invention. Detailed Implementation
[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0029] The present invention will now be described in further detail with reference to the accompanying drawings:
[0030] This invention discloses a method for controlling the crystal field symmetry of rare-earth-doped fluorine-oxygen microcrystalline glass, comprising:
[0031] Step 1: Mix the fluorine-oxygen microcrystalline glass raw material with ethanol, and grind it with zirconia balls in a ball mill for 12 hours. After mixing evenly, dry it in an oven. Then, place the dried powder mixture in an alumina crucible and melt it at a high temperature of 1450-1550℃ for 1-1.5 hours with the lid on. Press the molten material into sheet-like precursor glass and anneal it to room temperature in a muffle furnace to obtain a precursor glass with transparent characteristics.
[0032] Fluoro-oxygen microcrystalline glass raw materials include a matrix glass material and rare earth fluorides. The rare earth fluorides include LuF3 and at least one of ErF3, YbF3, HoF3 and TmF3. That is, in addition to LuF3, the rare earth fluorides also include at least one of ErF3, YbF3, HoF3 and TmF3.
[0033] Specifically, by molar percentage, the raw materials for fluorine-oxygen microcrystalline glass include a matrix glass material and rare earth fluorides. The rare earth fluorides include 40-45% SiO2, 20-25% Al2O3, 15-17% Na2O, 8-12% NaF, 5-10% YF3, and 1-5% ReF3, where Re is Lu. 3+ And Er 3+ Yb 3+ Ho 3+ and Tm 3+A combination of at least one of the following: preferably, NaF has a molar percentage of 8-10%, YF3 has a molar percentage of 8-10%, and ReF3 has a molar percentage of 1-3%; more preferably, Lu... 3+ The molar percentage of the dopant is 0.005-0.25%;
[0034] Step 2: Place the precursor glass in a muffle furnace and heat it to 650-660℃ at a heating rate of 10-20K / min and perform heat treatment for 1-3 hours to obtain rare earth ion doped fluorine-oxygen microcrystalline glass; wherein the microcrystalline phase of the obtained fluorine-oxygen microcrystalline glass is Y5O4F7, the crystal form is an orthorhombic Vernier phase, and the grain size is 20nm-40nm.
[0035] The advantages of this invention are:
[0036] By introducing Lu, an optically inert rare earth ion with a small ionic radius 3+ This reduces the local symmetry of the rare-earth ion crystal field in Y5O4F7 nanocrystals. Lower lattice symmetry enables fluorine-oxygen glass-ceramics to exhibit high luminous efficiency, high thermal stability, and high photothermal sensing sensitivity, making them widely applicable in high-performance photothermal sensing materials.
[0037] Table 1 below shows the composition of fluorine-oxygen microcrystalline glass in five specific embodiments.
[0038] Table 1. Chemical composition (mol%) of fluorine-oxygen microcrystalline glass in Examples 1-5
[0039]
[0040]
[0041] The preparation methods for Examples 1-5 are as follows:
[0042] S1. Accurately convert the molar percentages of the glass composition in Examples 1-5 of Table 1 into the corresponding mass of the raw materials, and accurately weigh the mass of each component's corresponding raw material, wherein Lu 3+ As an important rare earth doping ion, it plays a role in reducing the local symmetry of the rare earth ion crystal field. The raw material is mixed with ethanol and then ground with zirconium oxide balls in a ball mill for 12 hours. After being mixed evenly, it is placed in an oven to dry and obtain dried powder feed.
[0043] S2. Transfer the dried powder batch to an alumina crucible, cover it, and melt it at 1500℃ for 1 hour in an air atmosphere; hydraulically mold the glass into sheet glass; quickly place it in a muffle furnace for annealing to obtain sheet precursor glass;
[0044] S3. The obtained transparent precursor glass is placed in a muffle furnace and heated to 650°C at a heating rate of 10K / min and heat-treated for 2 hours. Then it is cooled down with the furnace to obtain rare earth ion-doped microcrystalline glass material.
[0045] The XRD diffraction patterns of the glass-ceramic samples prepared in Examples 1-5 are as follows: Figure 1 As shown, Y5O4F7 nanocrystals were precipitated in Examples 1-5, and Lu... 3+ Small amounts of ion doping do not cause significant changes in the crystal structure of nanocrystals.
[0046] The transmittance performance test results of the microcrystalline glass samples prepared in Examples 1-5 are as follows: Figure 2 As shown, the results indicate that a small amount of Lu 3+ Adding it will not affect the transmittance of the microcrystalline glass.
[0047] The fluorescence emission spectroscopic performance test results of the microcrystalline glass samples prepared in Examples 1-5 are as follows: Figure 3 As shown, the results indicate that under 980nm laser pumping, the increase in the green light emission region in Examples 1-5 increases with Lu 3+ The content increases initially and then decreases. This is because Lu 3+ The doping of rare earth ions causes lattice distortion and a decrease in lattice symmetry in nanocrystals, which enhances the electro-acoustic coupling of rare earth ions and the probability of electron transition, thus realizing efficient upconversion luminescence of glass-ceramics.
[0048] The relative photothermal sensitivity values S of the microcrystalline glass samples prepared in Examples 1-5 R The relationship between (300K) and Ω2 value is as follows: Figure 4 As shown, the Judd-Ofelt theory is a theoretical model for the spectral performance of lanthanide rare earth ion ff transitions. Using the least squares method of a linear equation system, the JO intensity parameters Ω2, Ω4, and Ω6 can be fitted. Parameter Ω2 has high sensitivity to the lattice symmetry of the local environment of the doped rare earth ion; a larger Ω2 value indicates lower symmetry. The relative photothermal sensitivity value S of the microcrystalline glass sample at 300K is shown. R With Lu 3+ The content of rare earth ions initially increases and then decreases, exhibiting the same trend as the Ω² value, which reflects the local symmetry of the rare earth ion crystal field in Y₅O₄F₇ nanocrystals. When Lu… 3+ The Ω² value is highest when the doping content is 0.25 mol%, and the maximum relative photothermal sensing sensitivity reaches 1.504% K at room temperature. -1 .
[0049] The present invention also proposes the application of a method for controlling the crystal field symmetry of rare earth-doped fluorine-oxygen microcrystalline glass as disclosed in any of the above embodiments in non-contact temperature sensor materials. Since the fluorine-oxygen microcrystalline glass prepared by the present invention has high photothermal sensitivity, it can effectively monitor temperature changes when applied to non-contact temperature sensor materials.
[0050] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A method for controlling the symmetry of the crystal field of a rare earth doped oxyfluoride glass-ceramic, characterized in that, Comprise: The oxyfluoride glass-ceramic raw material is mixed with ethanol and ground uniformly, and then high-temperature melting, pressing and annealing are performed to obtain a precursor glass with transparent characteristics; wherein the oxyfluoride glass-ceramic raw material comprises a base glass substance and rare earth fluoride, and comprises 40-45% of SiO2, 20-25% of Al2O3, 15-17% of Na2O, 8-12% of NaF, 5-10% of YF3 and 1-5% of ReF3 (wherein Re is Lu) according to the molar percentage 3+ and a combination of at least one of Er 3+ , Yb 3+ , Ho 3+ and Tm 3+ . The precursor glass is crystallized to obtain the oxyfluoride glass ceramic doped with rare earth ions; wherein the crystalline phase of the oxyfluoride glass ceramic is Y5O4F7, the crystal form is orthorhombic Vernier phase, and the grain size is 20-40 nm.
2. The method of claim 1, wherein the rare earth doped oxyfluoride glass- ceramic is doped with a rare earth element selected from the group consisting of Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and combinations thereof. The molar percentage of NaF is 8-10%, the molar percentage of YF3 is 8-10%, and the molar percentage of ReF3 is 1-3%.
3. The method of claim 1 or 2, wherein the rare-earth doped oxyfluoride glass- ceramic is characterized by a symmetry of the crystal field. Lu 3+ incorporation molar percentage is 0.005-0.25%.
4. The method of claim 1, wherein the rare-earth doped oxyfluoride glass- ceramic is doped with a concentration of the rare-earth dopant in the range of 0.1- 10 mol%. The oxyfluoride glass ceramic raw material is mixed with ethanol and ground uniformly, and then high-temperature melting, pressing and annealing are performed to obtain the precursor glass with transparent characteristics; comprising: The oxyfluoride glass ceramic raw material is mixed with ethanol and ground with zirconia balls in a ball mill, and after mixing uniformly, it is dried in an oven; then the dried powder mixture is placed in an alumina crucible and high-temperature melting is performed under a covered state; the melted material is pressed into a sheet-shaped precursor glass, and further moved to a muffle furnace for annealing to obtain the precursor glass with transparent characteristics.
5. The method for controlling the crystal field symmetry of rare-earth-doped fluorine-oxygen microcrystalline glass as described in claim 1 or 4, characterized in that, The melting temperature of high-temperature melting is 1450-1550℃, and the melting time is 1-1.5h.
6. The method of claim 1, wherein the rare earth doped oxyfluoride glass- ceramic is doped with a concentration of the rare earth dopant in the range of 0.1 to 10 atomic percent. The precursor glass is crystallized to obtain the oxyfluoride glass ceramic doped with rare earth ions; Comprise: The precursor glass is placed in a muffle furnace and heated to 650-660℃ at a heating rate of 10-20K / min and heat treated for 1-3h to obtain the oxyfluoride glass ceramic doped with rare earth ions.
7. Application of a rare earth-doped oxyfluoride glass ceramic in a non-contact temperature sensor material, wherein the rare earth-doped oxyfluoride glass ceramic is prepared by the method for regulating the symmetry of the crystal field according to any one of claims 1-6.