High-sensitivity optical pressure measuring material, preparation method and application thereof in pressure sensing

Abstract

The application discloses a kind of high-sensitivity optical pressure measuring materials, belongs to luminescent material preparation and application technical field. Plasma direct current arc discharge method is used to prepare Zn doped Gd2O2S (Gd2O2S:Zn) material, wherein Zn doping concentration is 1%-5%. Under ultraviolet light excitation, the material emits strong blue light, and the emission center is located at 457.9nm. With the increase of pressure from 1atm to 32Pa, the emission peak center wavelength is red shifted from 457.9nm to 563.2nm, and the pressure sensitivity is dλ / dP=3.3nm / Pa, which is 9 times of commercial ruby sensor. At the same time, the half-height width of emission peak is widened from 87.6nm to 145.0nm, and the corresponding sensitivity is dΓ / dP=1.9nm / Pa. To expand the pressure response range and improve the measurement accuracy, CIE-x color coordinates also show good linear growth, thereby supporting reliable pressure calibration. The Gd2O2S:Zn material prepared by the application shows important application potential in high-pressure detection in complex environment, and is a candidate material with great pressure measuring application prospect.

Description

Technical Field

[0001] This invention relates to the field of luminescent materials for high-sensitivity optical pressure measurement, and specifically to a high-sensitivity optical pressure measurement material and its preparation method. Background Technology

[0002] Lanthanide oxysulfides, especially gadolinium oxysulfide (Gd₂O₂S), are considered ideal luminescent matrix materials due to their high chemical stability, thermal stability, and wide bandgap (approximately 4.6–4.8 eV). These materials have a hexagonal crystal structure and, after doping, can achieve a broad spectral response of 380–680 nm, and have already achieved commercial applications in medical imaging, solid-state lighting, and other fields. Currently, rare earth ions (such as Eu)... 3+ 、Tb 3+ The Gd2O2S doped system (etc.) has been extensively studied and has shown excellent luminescence performance.

[0003] In contrast, transition metal ion doping (such as Zn) 2+ Due to its low precursor cost, Zn is an economical alternative. 2+ The ionic radius (74 pm) of Gd 3+ Significant differences exist between (104 pm), and coupled with charge imbalance, this can introduce structural perturbations into the matrix lattice, promoting oxygen vacancies and thus affecting the recombination pathway of photogenerated carriers at the luminescent centers. Studies have shown that Zn... 2+ Doping in wide-bandgap semiconductors can induce efficient blue light emission, demonstrating its potential as a light-emitting center. However, there are currently no systematic reports on the material research of Gd2O2S:Zn and its photoluminescence properties, let alone related patents or literature on its application in high-voltage optical sensing.

[0004] In the field of high-pressure measurement, diamond anvil cell (DAC) technology is often used to generate high pressures ranging from several gigapascals to hundreds of gigapascals. Currently commonly used optical pressure measurement materials include ruby ​​(Al₂O₃:Cr). 3+ ) and samarium-doped borate (SrB4O7:Sm 2+ Although widely used, optical pressure measurement techniques have low pressure sensitivity (dλ / dP≈0.25–0.35nm / GPa) and are susceptible to temperature interference. In addition, traditional optical pressure measurement techniques mostly rely on single-parameter sensing (such as emission peak position shift), lack self-calibration capabilities, and are difficult to guarantee both high accuracy and high reliability at the same time. Summary of the Invention

[0005] The technical problem to be solved by this invention is to provide a highly sensitive optical pressure measuring material suitable for high-pressure extreme environments and its preparation method. This material exhibits significantly improved temperature sensitivity, can be used in precision measurement fields, and has a simple structure. The preparation method is simple, easy to implement, safe, and environmentally friendly. To achieve the above objective, this invention adopts the following technical solution: A high-sensitivity optical pressure measurement material has the chemical formula Gd2O2S:Zn, wherein Zn is a dopant ion and the molar percentage concentration of Zn is 1% to 5%.

[0006] A method for preparing a high-sensitivity optical pressure-measuring material, characterized by comprising the following steps: (1) Weigh Gd2O3 powder and ZnS powder at a mass ratio of 0.15~0.3:1, mix them evenly, and then compress them to obtain ingot blanks; (2) Place the ingot obtained in step (1) into a graphite crucible in the reaction chamber of the DC arc discharge device; repeatedly introduce sufficient argon gas into the reaction chamber to replace and remove oxygen and water vapor in the device; (3) Under the conditions of voltage 20~40V and current 100~150A, the discharge reaction is carried out for 30~60 seconds, and the high temperature generated by the discharge promotes the reaction of Gd2O3 with ZnS to generate Gd2O2S:Zn. (4) After the reaction is completed, argon gas is introduced into the reaction chamber again for passivation treatment. After cooling, Gd2O2S:Zn fluorescent powder is collected in a graphite crucible.

[0007] A pressure detection method based on the above materials is characterized in that pressure detection is achieved by monitoring the relationship between pressure and one or more optical parameters in the fluorescence spectrum; the optical parameters include fluorescence peak position, fluorescence half width at half maximum, and x or y value in CIE-1931 chromaticity coordinates.

[0008] The fluorescence peak center wavelength λ (unit: nm) and pressure P (unit: GPa) satisfy a linear relationship: λ = 431.10 + 3.30P.

[0009] The fluorescence half-width at half maximum (FWHM) Γ (in nm) and the pressure P (in GPa) satisfy a linear relationship: Γ = 98.22 + 1.92P.

[0010] The CIE-x value of the fluorescent chromaticity coordinates has a linear relationship with the pressure P (unit: GPa): x = 0.14082 + 0.00793P.

[0011] The CIE-y value of the fluorescent chromaticity coordinates and the pressure P (unit: GPa) satisfy a quadratic polynomial relationship: y = 0.13162 + 0.02559P - 4.5354 × 10 -4P 2 .

[0012] An application of a high-sensitivity optical pressure-sensing material in pressure sensing is characterized in that the optical pressure-sensing material is Gd₂O₂S:Zn as described in claim 1; by detecting the shift in its fluorescence peak position, the absolute pressure sensitivity is obtained as dλ / dP = 3.3 nm / GPa; by detecting the change in its fluorescence half-width at half-maximum (FWHM), the absolute pressure sensitivity is obtained as dΓ / dP = 1.9 nm / GPa; and by detecting the change in its fluorescence chromaticity coordinate (CIE-x) value, the absolute pressure sensitivity is obtained as dx / dP = 0.00793 GPa. -1 .

[0013] Beneficial effects: Innovative preparation method: The preparation process described in this invention does not require the use of templates or catalysts, has low preparation cost, is simple and easy to operate, and is safe and environmentally friendly.

[0014] Materials Innovation: Proposing a Zn-based approach 2+ Gd₂O₂S:Zn luminescent materials were constructed using Zn as a dopant ion. 2+ With Gd 3+ The ionic radius mismatch and charge difference between the components introduce lattice distortion and defect states into the matrix, enhancing the spectral response of the material under high pressure.

[0015] Multi-mode optical pressure measurement strategy: Breaking through the traditional single-parameter sensing mode, this approach proposes to simultaneously monitor the changes in three optical parameters: fluorescence peak position (λ), fluorescence half-width at half-maximum (Γ), and CIE-1931 chromaticity coordinates (x, y), and establish their linear or functional relationship with pressure. Through multi-parameter cross-validation, self-calibration measurement under high-pressure conditions is achieved, significantly improving the accuracy and reliability of pressure readings.

[0016] Advantages in high-pressure sensitivity: This material system exhibits a significant spectral response under high pressure, with an absolute sensitivity of dλ / dP = 3.3 nm / GPa for fluorescence peak shift, which is much higher than that of traditional calibration materials such as ruby ​​(0.35 nm / GPa), making it suitable for high-pressure environments of tens of gigapas or even hundreds of gigapas. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. However, the scope of protection claimed by the present invention is not limited to the scope described in the embodiments.

[0018] Figure 1 This is a schematic diagram of the reaction apparatus used in the method of the present invention; Figure 2 This is the XRD pattern of Gd2O2S:Zn prepared in Example 1; Figure 3 The emission spectrum changes of Gd2O2S:Zn prepared in Example 1 within the pressure range of 0–32 GPa are shown in (a); the peak center (b) and full width at half maximum (FWHM) of the emission band change with pressure during compression-decompression cycling are shown in (c). Figure 4 Here are the CIE chromaticity diagrams of Gd2O2S:Zn prepared in Example 1 under different pressures during compression (a), (b) the relationship between the x-coordinate and pressure, and (c) the relationship between the y-coordinate and pressure. Figure 5 The Raman spectra of Gd2O2S:Zn prepared in Example 1 under different pressures during compression; Figure 6 This is the EDS spectrum of undoped Gd2O2S prepared in Example 2; Figure 7 This is the emission spectrum of undoped Gd2O2S prepared in Example 2; Figure 8 This is the XRD pattern of Gd2O2S:Zn prepared in Example 3; Figure 9 This is the PL spectrum of Gd2O2S:Zn prepared in Example 3; Figure 10 This is the XRD pattern of Gd2O2S:Zn prepared in Example 4; Figure 1 In the middle: 1. Reaction chamber; 2. Condensation wall; 3. Tungsten cathode; 4. Reaction raw materials; 5. Graphite crucible anode; 6. Copper base (including water inlet and water outlet); 7. Gas inlet; 8. Gas outlet; 9. Condensation wall water inlet; 10. Condensation wall water outlet. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0020] Figure 1 This is a schematic diagram of the reaction apparatus used in the method of the present invention.

[0021] like Figure 1As shown, reaction chamber 1 is enclosed by condenser wall 2, tungsten rod cathode 3, and graphite crucible anode 5. The side of graphite crucible anode 5 opposite to tungsten rod cathode 3 is filled with reactant material 4. An arc is formed between graphite crucible anode 5 and tungsten rod cathode 3 by controlling the raising and lowering of copper base 6. To ensure the smooth condensation of the reaction product, circulating cooling water is introduced through graphite crucible anode 5 and condenser wall 2. Copper base 6 serves as both inlet and outlet, and cooling water circulates through inlet 9 and outlet 10 in condenser wall 2. Before and after the reaction, reaction gas is introduced through inlet 7 and outlet 8 for gas washing, flushing, and passivation. Finally, the product is obtained at graphite crucible anode 5.

[0022] Example 1 In this embodiment, Gd2O2S:Zn (doped at a concentration of 3.7%) was prepared. The material preparation process is as follows: Gd₂O₃ powder and ZnS powder were weighed at a mass ratio of 0.2:1. 3g of each powder was mixed thoroughly and pressed into an ingot 4 with a diameter of 1.8cm and a height of 2cm using a tableting mold. The ingot 4 was placed in a graphite crucible 5 within the reaction chamber of a DC arc discharge device, and a tungsten cathode 3 was fixed at a certain distance above the reactant 4. The reaction chamber 1 was evacuated to a vacuum, and argon gas was repeatedly introduced into the chamber to remove oxygen and water. Then, 20kPa nitrogen gas was introduced as the reaction gas. The circulating water system was turned on, and cooling water was introduced through the copper base 6 and the condenser wall 2. The height of the copper base 6 was adjusted so that the graphite crucible 5 and the tungsten cathode 3 made contact momentarily, initiating an arc discharge. During the discharge process, the voltage was maintained at 30V, the current at 120A, and the reaction time at 40s. The reaction product, Gd₂O₂S:Zn phosphor, was collected in the graphite crucible.

[0023] Figure 2 The XRD pattern shows that the positions and relative intensities of all the XRD diffraction peaks of Gd₂O₂S:Zn are in good agreement with the data from PDF card number 26-1422, indicating that the sample is Gd₂O₂S with a hexagonal structure in space group P-3ml. Although the initial raw material has a high proportion of ZnS, no other crystal phases related to Zn and ZnS were detected in the XRD pattern, indicating that the sample has high purity. Figure 2 The EDS elemental mapping images (ae) and spectra (f) show that Gd, O, S, and Zn are uniformly distributed on the sample. According to the EDS measurements, Zn accounts for 3.7%.

[0024] Figure 3 (a) The PL spectra under different pressures show that, under normal pressure, the luminescence center of Gd₂O₂S:Zn is at 457.85 nm, with a full width at half maximum (FWHM) of 87.60 nm. Based on the recorded emission spectra, the center wavelength of the emission band under different pressures was evaluated, and the results are as follows: Figure 3As shown in (b), as the pressure increases from 0 GPa to 32 GPa, the emission band center redshifts from 457.85 nm to 563.17 nm. The change in the emission peak center with pressure can be well fitted by a linear relationship, with the fitting equation being λ = 431.10 + 3.30P, and the goodness of fit R0. 2 =0.99. The full width at half maximum (FWHM) is derived from the pressure-dependent emission spectrum (e.g., ...). Figure 3 (c)). The width Γ of the PL band is approximately 87.60 nm, and it broadens to 145.0 nm with increasing pressure. A linear correlation was used to fit this change to pressure (R0). 2 =0.99), and the relationship is: Γ=98.22+1.92P. After depressurization, when the pressure in the DAC is gradually released to the ambient conditions, the calculated spectral center and half-width at half-maximum (WHM) of the spectrum are restored to the corresponding values ​​of the compression path, which shows that these two parameters have significant reversibility under high pressure.

[0025] Figure 4 (a) It can be seen that the chromatic coordinates of Gd2O2S:Zn shift significantly with increasing pressure. Based on the significant changes in CIE chromatic coordinates, high-precision pressure sensing can be achieved by analyzing the dependence of chromatic coordinates on pressure. Figure 4 (b) and (c) respectively show the fitting relationship between pressure (P) and the x and y color coordinates. The former conforms to a linear function, and the latter conforms to a quadratic polynomial function, with the specific expressions as follows: x = 0.14082 + 0.00793P y = 0.13162 + 0.02559P - 4.5354 × 10 -4 P 2 Figure 5 The Raman spectrum shows that under normal pressure, there are four Raman peaks (labeled R1, R2, R3, and R4), corresponding to the low-frequency Eg and A1g and high-frequency Eg and A1g vibrational modes, respectively, which are typical characteristics of the Gd2O2S crystal structure. As the pressure increases to 35 GPa, the four Raman peaks remain unchanged, indicating that Gd2O2S exhibits structural temperature under high pressure, making it suitable as a pressure sensing material.

[0026] Example 2 In this embodiment, undoped Gd₂O₂S was prepared. The material preparation process is as follows: Gd₂O₃ powder and S powder were weighed at a mass ratio of 0.3:1. 3g of each powder was mixed thoroughly and pressed into an ingot 4 with a diameter of 1.8cm and a height of 2cm using a tableting mold. The ingot 4 was placed in a graphite crucible 5 within the reaction chamber of a DC arc discharge device, and a tungsten cathode 3 was fixed at a certain distance above the reactant 4. The reaction chamber 1 was evacuated to a vacuum, and argon gas was repeatedly introduced into the chamber to remove oxygen and water. Then, 20kPa nitrogen gas was introduced as the reaction gas. The circulating water system was turned on, and cooling water was introduced through the copper base 6 and the condenser wall 2. The height of the copper base 6 was adjusted so that the graphite crucible 5 and the tungsten cathode 3 made contact momentarily, instantly igniting an arc and initiating discharge. During the discharge process, the voltage was maintained at 30V, the current at 120A, and the reaction time at 40s. The reaction product, Gd₂O₂S, was collected in the graphite crucible.

[0027] Figure 6 The EDS spectrum shows that the sample is composed of Gd, O and S elements, and the surface preparation is a Gd2O2S sample. Figure 7 The PL spectrum shows that the emission peak of Gd2O2S is Gd 3+ The energy level emission peaks of the ions are fundamentally different from those of Gd₂O₂S:Zn. Five characteristic peaks were observed in the wavelength range of 460-515 nm, and these peaks originate from Gd₂O₂S:Zn. 3+ high energy 6 G j State and V Gd Radiative transitions between defect energy levels. Transitions observed in the 560–640 nm wavelength range correspond to... 6 G 13 / 2→ 6 P7 / 2 and 6 G7 / 2→ 6 P7 / 2 represents an intra-configuration 4f-4f transition. Comparing Gd₂O₂S:Zn, no broad blue emission peak is observed in the undoped Gd₂O₂S sample.

[0028] Example 3 In this embodiment, Gd2O2S:Zn (doping concentration of 1.0%) was prepared. The material preparation process is as follows: Gd₂O₃ powder and ZnS powder were weighed at a mass ratio of 0.3:1. 3g of each powder was mixed thoroughly and pressed into an ingot 4 with a diameter of 1.8cm and a height of 2cm using a tableting mold. The ingot 4 was placed in a graphite crucible 5 within the reaction chamber of a DC arc discharge device, and a tungsten cathode 3 was fixed at a certain distance above the reactant 4. The reaction chamber 1 was evacuated to a vacuum, and argon gas was repeatedly introduced into the chamber to remove oxygen and water. Then, 20kPa nitrogen gas was introduced as the reaction gas. The circulating water system was turned on, and cooling water was introduced through the copper base 6 and the condenser wall 2. The height of the copper base 6 was adjusted so that the graphite crucible 5 and the tungsten cathode 3 made contact momentarily, instantly igniting an arc for discharge. During the discharge process, the voltage was maintained at 30V, the current at 120A, and the reaction time at 40s. The reaction product, Gd₂O₂S:Zn, was collected in the graphite crucible.

[0029] Figure 8 The XRD pattern shows that the positions and relative intensities of all XRD diffraction peaks of Gd2O2S:Zn are in good agreement with the data of PDF card number 26-1422, which indicates that the sample is Gd2O2S. Figure 9 The PL spectrum shows that the luminescence center and luminescence peak shape of Gd2O2S:Zn are consistent with those of the Gd2O2S:Zn sample in Example 1.

[0030] Example 4 In this embodiment, Gd2O2S:Zn was prepared. The material preparation process is as follows: Gd₂O₃ powder and ZnS powder were weighed at mass ratios of 0.3:1.5, 0.3:2, and 0.1:1. 3g of each powder was mixed thoroughly and pressed into an ingot 4 with a diameter of 1.8cm and a height of 2cm using a tableting mold. The ingot 4 was placed in a graphite crucible 5 within the reaction chamber of a DC arc discharge device, and a tungsten cathode 3 was fixed at a certain distance above the reactant 4. The reaction chamber 1 was evacuated to a vacuum, and argon gas was repeatedly introduced into the chamber to remove oxygen and water. Then, 20kPa nitrogen gas was introduced as the reaction gas. The circulating water system was turned on, and cooling water was introduced through the copper base 6 and the condenser wall 2. The height of the copper base 6 was adjusted so that the graphite crucible 5 and the tungsten cathode 3 made contact momentarily, initiating an arc discharge. During the discharge process, the voltage was maintained at 30V, the current at 100A, and the reaction time at 20s. The reaction products, Gd₂O₂S:Zn and impurities, were collected in the graphite crucible.

[0031] Figure 10 The XRD patterns of the samples prepared at mass ratios of 0.3:1.5, 0.3:2, and 0.1:1 are shown in the figures. It can be seen from the figures that the prepared samples, in addition to the Gd2O2S:Zn sample, also contain impurities such as ZnS and S.

[0032] Table 1. Comparison of pressure sensing performance of the present invention's Gd2O2S:Zn with previously reported optical pressure sensor materials. The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A high-sensitivity optical pressure measurement material, having the chemical formula Gd2O2S:Zn, wherein Zn is a dopant ion and the molar percentage concentration of Zn is 1% to 5%.

2. A method for preparing a material, used to prepare the high-sensitivity optical pressure measuring material as described in claim 1, characterized in that, Includes the following steps: (1) Weigh Gd2O3 powder and ZnS powder at a mass ratio of 0.15~0.3:1, mix them evenly, and then compress them to obtain ingot blanks; (2) Place the ingot obtained in step (1) into a graphite crucible in the reaction chamber of the DC arc discharge device; repeatedly introduce sufficient argon gas into the reaction chamber to replace and remove oxygen and water vapor in the device; (3) Under the conditions of voltage 20~40V and current 100~150A, the discharge reaction is carried out for 30~60 seconds, and the high temperature generated by the discharge promotes the reaction of Gd2O3 with ZnS to generate Gd2O2S:Zn. (4) After the reaction is completed, argon gas is introduced into the reaction chamber again for passivation treatment. After cooling, Gd2O2S:Zn fluorescent powder is collected in a graphite crucible.

3. The preparation method according to claim 2, characterized in that, In step (1), the total mass of the mixed powder of Gd2O3 and ZnS is 3g.

4. A pressure detection method, characterized in that, Using the high-sensitivity optical pressure measuring material as described in claim 1, pressure detection is achieved by monitoring the relationship between one or more optical parameters in its fluorescence spectrum and pressure; the optical parameters include fluorescence peak position, fluorescence half-width, and x or y value in CIE-1931 chromaticity coordinates.

5. The pressure detection method according to claim 4, characterized in that, The center wavelength λ of the fluorescence peak satisfies a linear relationship with the pressure P: λ = 431.10 + 3.30P.

6. According to the pressure detection method of claim 5, the fluorescence half-width Γ and the pressure P satisfy a linear relationship: Γ = 98.22 + 1.92P.

7. The pressure detection method according to claim 5, characterized in that, The CIE-x value of the fluorescent chromaticity coordinates has a linear relationship with the pressure P: x = 0.14082 + 0.00793P; The CIE-y value of the fluorescent chromaticity coordinates and the pressure P satisfy a quadratic polynomial relationship: y = 0.13162 + 0.02559P - 4.5354 × 10 -4 P 2 .

8. The application of a high-sensitivity optical pressure sensing material in pressure sensing, characterized in that, The optical pressure measuring material is Gd₂O₂S:Zn as described in claim 1; by detecting the shift in its fluorescence peak position, the absolute pressure sensitivity is obtained as dλ / dP = 3.3 nm / GPa; by detecting the change in its fluorescence half-width at half-maximum (FWHM), the absolute pressure sensitivity is obtained as dλ / dP = 1.9 nm / GPa; by detecting the change in its fluorescence chromaticity coordinate (CIE-x) value, the absolute pressure sensitivity is obtained as dx / dP = 0.00793 GPa. -1 .

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