A crystal, a rare earth doped crystal and a preparation method and application thereof

Abstract

This application discloses a crystal, a rare-earth-doped crystal, its preparation method, and its applications, belonging to the field of crystal materials. The chemical formula of the crystal is [Gd(L)]. 1.5 (DMA)] n Formula I; in Formula I, L is a ligand formed by deprotonated benzene polycarboxylic acid; benzene polycarboxylic acid is selected from any one of terephthalic acid, phthalic acid, and isophthalic acid; DMA is N , N -Dimethylacetamide; n ∞ represents continuous repetition and infinite extension. The crystal is rare-earth doped, and the chemical formula of the rare-earth doped crystal is [Gd]. 1‑x% (L) 1.5 (DMA)] n :x% Ln 3+ Equation II; in Equation II, x = 0.1~10; Ln 3+ Selected from Tb 3+ Or Eu 3+ Any one of the following. It has potential application value in fields such as fluorescent materials, multicolor display materials, long afterglow materials, X-ray detection and imaging materials, radiation detection dosimeters, and optical information encryption. The preparation method used in this application can be easily achieved through solution reaction under relatively mild conditions, with low cost and strong industrial feasibility.

Description

Technical Field

[0001] This application relates to a crystal, a rare earth-doped crystal, its preparation method and application, and belongs to the field of crystal materials. Background Technology

[0002] Long-afterglow materials have attracted widespread attention in the fields of display lighting, chemical sensing, bioimaging, and information security. However, existing long-afterglow materials still face challenges such as harsh reaction conditions and complex synthesis processes. Furthermore, due to the inherent competition between exciton trapping and rapid exciton recombination, long-afterglow materials typically exhibit low photoluminescence quantum yields, making it difficult to achieve efficient photoluminescence or X-ray scintillation. Metal-organic frameworks (MOFs), crystalline materials constructed from inorganic nodes (metal atoms or metal clusters) and organic ligands, possess advantages such as functional tunability, structural designability, and mild synthesis processes, showing great potential in radiation detection and long-afterglow luminescence. Summary of the Invention

[0003] In view of the above, this application aims to solve at least one of the problems existing in the field of long afterglow materials, such as harsh reaction conditions, long synthesis cycle, and low photoluminescence quantum yield. This application provides a photophysical modulation strategy by doping Tb into gadolinium-based metal-organic frameworks (MOFs). 3+ / Eu 3+ This achieves spatial separation between the long-afterglow luminescence center and the photoluminescence center, thereby enabling ligand-based long-afterglow luminescence and Tb-based luminescence. 3+ / Eu 3+ This application provides a rare-earth-doped long-persistence / scintillation material that can be synthesized under a simple solvothermal reaction. This material emits a noticeable long-persistence emission under a 365nm ultraviolet lamp, based on Ln... 3+ The duration of afterglow emission can be adjusted (0-4.5 s) depending on the ion doping ratio; the compound also exhibits efficient photoluminescence and scintillation properties, with high photoluminescence quantum yield, strong scintillation intensity, high scintillation output and low X-ray detection limit.

[0004] According to a first aspect of this application, a crystal is provided. This crystal exhibits good water, thermal, and radiation stability, and displays visible luminescence under both ultraviolet and X-ray irradiation.

[0005] A crystal, the chemical formula of which is [Gd(L) 1.5 (DMA)] n Formula I; In formula I, L is a ligand formed from deprotonated benzene polycarboxylic acids; The benzene polycarboxylic acid is selected from any one of terephthalic acid, phthalic acid, and isophthalic acid; DMA is N , N -Dimethylacetamide; n The value ∞ indicates that it is repeated and extended infinitely.

[0006] Optionally, the crystal has a three-dimensional framework structure; The smallest asymmetric structural unit of the three-dimensional structure contains 1.5 L... 2– ligand, 1 Gd 3+ Metal ions, 1 DMA molecule; Gd is an octagonal configuration of Gd. 3+ Metal ions; The Gd 3+ Metal ions react with four L... 2– The seven O atoms on the carboxylate group of the ligand are coordinated with one O atom on the DMA.

[0007] Specifically, the chemical formula of the crystal is [Gd(BDC)]. 1.5 (DMA)] n BDC is a ligand formed from deprotonated terephthalic acid.

[0008] In this application, the material design strategy for preparing materials exhibiting both long-afterglow luminescence and high photoluminescence quantum yield is to construct rare-earth-doped Gd-based MOFs using long-afterglow ligands. The organic ligands can be any one of terephthalic acid, phthalic acid, or isophthalic acid, which also exhibit long-afterglow luminescence; the host metal element is Gd, and the dopant elements are selected from Tb, Eu, or any mixture of both in any proportion. This design strategy is simple and widely applicable.

[0009] Optionally, when L is a ligand formed from deprotonated terephthalic acid, the crystal belongs to the triclinic crystal system and has... P–1 Spatial group structure.

[0010] Preferably, the unit cell parameters of the crystal are: a = 9.7~9.8Å, b = 10.4~10.5Å, c = 10.5~10.7Å, α = 93~94°, β = 114~115°, γ = 116~118°, Z = 1, V = 830~840Å 3 .

[0011] Preferably, a = 9.72~9.75Å, b = 10.45~10.47Å, c = 10.59~10.62 Å, α = 93.1~93.5°, β = 114.1~114.5°, γ = 116.5~117.2°, V = 833~838Å 3 .

[0012] More preferably, α = 93.17~93.38°, β = 114.28~114.39°, γ = 116.93~117.02°.

[0013] Optionally, the crystal is rare-earth doped, and the chemical formula of the rare-earth doped crystal is: [Gd 1-x% (L) 1.5 (DMA)] n :x% Ln 3+ Formula II; In formula II, x = 0.1 ~ 10; Ln 3+ Selected from Tb 3+ Or Eu 3+ Any one of them.

[0014] Optionally, x is selected from any value of 0.1, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or a range of values ​​between any two.

[0015] Specifically, the chemical formula of the rare earth-doped crystal is [Gd]. 1-x% (L) 1.5 (DMA)] n :x% Ln 3+ BDC is a ligand formed from deprotonated terephthalic acid.

[0016] Optionally, the crystal has a size of 2mm × 2mm × 1mm.

[0017] Optionally, the thermal decomposition temperature of the crystal is ≥200℃.

[0018] Preferably, the thermal decomposition temperature of the crystal is ≥270℃.

[0019] The above thermal decomposition temperature indicates that the crystal has good thermal stability.

[0020] Optionally, the luminescence lifetime of the rare earth-doped crystal is 1.0~4.0 ms.

[0021] Preferably, the luminescence lifetime of the rare earth-doped crystal is 1.10~2.50 ms.

[0022] More preferably, the luminescence lifetime of the rare earth-doped crystal is 1.20~1.50 ms.

[0023] This crystalline compound is typically a colorless, transparent, bulk crystal with a three-dimensional structure. (Tb) 3+ Doped rare earth crystals ([Gd) 1-x% (BDC) 1.5 (DMA)] n :x% Tb 3+ It exhibits a dazzling green light under excitation by light with wavelengths of 280-400 nm and X-rays. 3+ Doped rare earth crystals ([Gd) 1-x% (BDC) 1.5 (DMA)] n :x% Eu 3+ It exhibits bright red light under excitation by light with wavelengths of 280-400 nm and X-rays. According to Ln... 3+ Different doping levels [Gd(BDC)] 1.5 (DMA)] n :x%Ln 3+ The afterglow duration under a 365 nm UV lamp can be 0 to 4.5 seconds.

[0024] Optionally, when it is Tb 3+ When doped, Tb 3+ Doped rare earth crystals emit green light when irradiated with ultraviolet light or X-rays.

[0025] Preferably, the Tb 3+ The RGB color coordinates of the green light of the doped rare earth crystal are (0.29~0.31, 0.61~0.63).

[0026] Preferably, the Tb 3+ The RGB color coordinates of the green light of the doped rare earth crystal are (0.295~0.305, 0.618~0.625).

[0027] Specifically, the Tb 3+ The RGB color coordinates of the green light of the doped rare earth crystal are (0.300, 0.621).

[0028] Optionally, the Tb 3+ The doped rare earth crystals emit a green afterglow after being irradiated with ultraviolet light.

[0029] Optionally, when it is Eu 3+ When doped, Eu 3+ Doped rare earth crystals emit red light when irradiated with ultraviolet light or X-rays.

[0030] Optionally, the Eu 3+ The RGB color coordinates of the red light of the doped rare earth crystal are (0.65~0.66, 0.33~0.34).

[0031] Preferably, the Eu 3+ The RGB color coordinates of the red light of the doped rare earth crystal are (0.652~0.658, 0.335~0.337).

[0032] Specifically, the Eu 3+ The RGB color coordinates of the red light of the doped rare earth crystal are (0.655, 0.336).

[0033] Optionally, the Eu 3+ The doped rare earth crystals emit a green afterglow after being irradiated with ultraviolet light.

[0034] Optionally, the Tb 3+ Doped rare earth crystals ([Gd) 1-x% (BDC) 1.5 (DMA)] n :x% Tb 3+ The photoluminescence quantum yield of the Eu is ≥60%. 3+ Doped rare earth crystals ([Gd) 1-x% (BDC) 1.5 (DMA)] n :x% Eu 3+ The photoluminescence quantum yield is ≥60%.

[0035] Optionally, the Tb 3+ Doped rare earth crystals ([Gd) 1-x% (BDC) 1.5 (DMA)] n :x% Tb 3+ The photoluminescence quantum yield of the Eu is ≥70%. 3+ Doped rare earth crystals ([Gd) 1-x% (BDC) 1.5 (DMA)] n :x% Eu 3+ The photoluminescence quantum yield is ≥70%.

[0036] Optionally, the Tb 3+ Doped rare earth crystals [Gd 1-x%(BDC) 1.5 (DMA)] n :x% Tb 3+ The X-ray light output is ≥10000 photons / MeV, and the Eu 3+ Doped rare earth crystals ([Gd) 1-x% (BDC) 1.5 (DMA)] n :x% Eu 3+ The X-ray light output is ≥3000 photons / MeV.

[0037] Preferably, the Tb 3+ Doped rare earth crystals ([Gd) 1-x% (BDC) 1.5 (DMA)] n :x% Tb 3+ The X-ray light output of the Eu is ≥20000 photons / MeV. 3+ Doped rare earth crystals ([Gd) 1-x% (BDC) 1.5 (DMA)] n :x% Eu 3+ The X-ray light output is ≥5000 photons / MeV.

[0038] Optionally, the Tb 3+ Doped rare earth crystals ([Gd) 1-x% (BDC) 1.5 (DMA)] n :x% Tb 3+ The scintillation intensity of the Eu scintillation crystal is 5 to 18 times that of the bismuth germanate (BGO) scintillation crystal. 3+ Doped rare earth crystals ([Gd) 1-x% (BDC) 1.5 (DMA)] n :x% Eu 3+ The scintillation intensity of bismuth germanate (BGO) scintillation crystal is 2 to 6 times that of bismuth germanate (BGO) scintillation crystal.

[0039] Optionally, the Tb 3+ Doped rare earth crystals ([Gd) 1-x% (BDC) 1.5 (DMA)] n :x% Tb 3+ The lower limit of X-ray detection is ≤300 nGy / s, and the Eu 3+ Doped rare earth crystals ([Gd) 1-x% (BDC) 1.5 (DMA)] n :x% Eu 3+ The lower limit of X-ray detection is ≤700 nGy / s.

[0040] Preferably, the Tb 3+ Doped rare earth crystals ([Gd) 1-x% (BDC) 1.5 (DMA)] n :x% Tb 3+ The lower limit of X-ray detection is ≤200 nGy / s, and the Eu 3+ Doped rare earth crystals ([Gd) 1-x% (BDC) 1.5 (DMA)] n :x% Eu 3+ The lower limit of X-ray detection is ≤600 nGy / s.

[0041] Preferably, the Tb 3+ Doped rare earth crystals ([Gd) 1-x% (BDC) 1.5 (DMA)] n :x% Tb 3+ The lower limit of X-ray detection is ≤100 nGy / s, and the Eu 3+ Doped rare earth crystals ([Gd) 1-x% (BDC) 1.5 (DMA)] n :x% Eu 3+ The lower limit of X-ray detection is ≤500 nGy / s.

[0042] More preferably, the Tb 3+ Doped rare earth crystals ([Gd) 1-x% (BDC) 1.5 (DMA)] n :x% Tb 3+ The lower limit of X-ray detection for Eu is 93.4 nGy / s. 3+ Doped rare earth crystals ([Gd) 1-x% (BDC) 1.5 (DMA)] n :x% Eu 3+ The lower limit of X-ray detection is 0.45 μGy / s.

[0043] Optionally, the [Gd(BDC)] 1.5 (DMA)] n and rare earth doped crystals [Gd 1-x% (BDC) 1.5 (DMA)] n :x% Ln 3+ The thermal decomposition temperature is ≥200℃.

[0044] Preferably, the [Gd(BDC)]1.5 (DMA)] n and rare earth doped crystals [Gd 1-x% (BDC) 1.5 (DMA)] n :x% Ln 3+ The thermal decomposition temperature is ≥270℃.

[0045] The above thermal decomposition temperature indicates that this rare earth-doped crystal has good thermal stability.

[0046] Optionally, the Tb 3+ Doped rare earth crystals ([Gd) 1-x% (BDC) 1.5 (DMA)] n :x% Tb 3+ The RGB color coordinates of the photoluminescence and flickering emission of the Eu are (0.299, 0.610). 3+ Doped rare earth crystals ([Gd) 1-x% (BDC) 1.5 (DMA)] n :x% Eu 3+ The RGB color coordinates of the photoluminescence and stroboscopic emission are (0.660, 0.338).

[0047] Optionally, the Tb 3+ / Eu 3+ Doped rare earth scintillation materials ([Gd 1-x% (BDC) 1.5 (DMA)] n :x% Tb 3+ It emits a green afterglow after being irradiated with ultraviolet light.

[0048] Optionally, the Tb 3+ Doped rare earth crystals ([Gd) 1-x% (BDC) 1.5 (DMA)] n :x% Tb 3+ The duration of the visible afterglow emission can be 0~4.5s, and the Eu... 3+ Doped rare earth crystals ([Gd) 1-x% (BDC) 1.5 (DMA)] n :x% Eu 3+ The duration of the visible afterglow can be 0~2s.

[0049] According to a second aspect of this application, a method for preparing the crystal described above is provided. The preparation method can be easily achieved through solution reaction under relatively mild conditions, is low in cost, and has strong industrial feasibility.

[0050] The crystal preparation method described above involves placing a mixed solution containing benzene polycarboxylic acid, a metal source, and a solvent in a sealed container and reacting it to obtain the crystal. The metal source is a Gd metal source, or The metal source is a Gd metal source and an Ln metal source, where Ln is selected from Tb or Eu. The solvent includes DMA.

[0051] Optionally, the Gd metal source is selected from at least one of Gd(NO3)3, Gd(CH3COO)3, and GdCl3; The Tb metal source is selected from at least one of Tb(NO3)3, Tb(CH3COO)3, and TbCl3, and the Eu metal source is selected from at least one of Eu(NO3)3, Eu(CH3COO)3, and EuCl3.

[0052] Optionally, the molar ratio of the metal source to the benzene polycarboxylic acid is 1:1; The molar amount of the metal source is expressed as the molar amount of the metal element in the metal source.

[0053] Optionally, the solvent includes at least one of DMA, water, methanol, ethanol, and a hydrogen halide solution.

[0054] Optionally, the hydrogen halide is selected from at least one of HCl and HBr.

[0055] Optionally, the total ratio of the metal source to the solvent is 0.1 mmol: 3~8 mL.

[0056] Optionally, the ratio of the metal source to DMA is 0.1 mmol: 3~5 mL.

[0057] Optionally, the volume ratio of DMA, at least one of water, methanol, and ethanol, and the hydrogen halide solution is 3-5 mL: 1-3 mL: 0.05-0.2 mL.

[0058] Optionally, the reaction temperature is 80~140℃, and the reaction time is 24~72 hours.

[0059] Preferably, the reaction temperature is 90~120℃ and the reaction time is 36~54 hours.

[0060] Specifically, the reaction temperature is 100℃ and the reaction time is 48 hours.

[0061] Optionally, the temperature of the reaction is independently selected from any value or a range between any two of 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, and 140°C.

[0062] Optionally, the reaction time is independently selected from any value of 24 h, 30 h, 36 h, 42 h, 48 h, 54 h, 60 h, 66 h, 72 h, or a range between any two.

[0063] As a preferred embodiment, the [Gd(BDC)] 1.5 (DMA)] n Methods for preparing crystals include: Gd(NO3)3(H2O)6 and terephthalic acid, in a molar ratio of 1:1, were placed in a 10 mL glass vial. Then, DMA, water, and HCl solvents were added, and a solvothermal reaction was initiated. The volume ratios of Gd(NO3)3(H2O)6 to DMA were 0.1 mmol:3 mL, the volume ratios of Gd(NO3)3(H2O)6 to water were 0.1 mmol:2 mL, and the volume ratios of Gd(NO3)3(H2O)6 to HCl were 0.1 mmol:0.1 mL. The reaction temperature was 100 °C. o At C, the reaction time was 48 h. After the reaction was completed, the mixture was cooled to room temperature, filtered, and washed with DMA and ethanol to obtain colorless bulk crystals, which are the three-dimensional [Gd(BDC)]. 1.5 (DMA)] n The yield was 59%.

[0064] As a preferred embodiment, the [Gd] 0.96 (BDC) 1.5 (DMA)] n 4% Tb 3+ Methods for preparing crystals include: A 10 mL glass vial was prepared by placing Tb(NO3)3(H2O)6, Gd(NO3)3(H2O)6, and terephthalic acid in a molar ratio of 0.04:0.96:1. Then, DMA, water, and HCl solvents were added, and a solvothermal reaction was initiated. The volume ratio of the total Tb(NO3)3(H2O)6 and Gd(NO3)3(H2O)6 metal sources to DMA was 0.1 mmol:3 mL, the volume ratio of the total Tb(NO3)3(H2O)6 and Gd(NO3)3(H2O)6 metal sources to water was 0.1 mmol:2 mL, and the volume ratio of the total Tb(NO3)3(H2O)6 and Gd(NO3)3(H2O)6 metal sources to HCl was 0.1 mmol:0.1 mL. The reaction temperature was 100 °C. o C, the reaction time was 48 h, after which the mixture was cooled to room temperature, filtered, and washed with DMA and ethanol to obtain colorless bulk crystals, which are the three-dimensional [Gd] 0.96 (BDC) 1.5 (DMA)] n 4% Tb 3+ The yield was 59%.

[0065] According to a third aspect of this application, an application of the crystal described above is provided. The crystal has potential application value in fields such as fluorescent materials, multicolor display materials, long afterglow materials, X-ray detection and imaging materials, radiation detection dosimeters, and optical information encryption.

[0066] The above-mentioned crystals are used in light-emitting diodes, X-ray detection materials, radiation detection dosimeters, radiation imaging devices, long afterglow luminescent materials, and information anti-counterfeiting encryption.

[0067] Rare earth-doped crystals can be used as photoluminescent and scintillation X-ray radiation detection and imaging devices, as well as as information anti-counterfeiting and encryption materials with long afterglow luminescence.

[0068] The rare-earth-doped crystals synthesized using the above method exhibit excellent scintillation output, low detection limit, and high radiation stability when used as scintillation materials. Furthermore, these crystals also demonstrate superior luminous efficiency and a relatively long afterglow duration when used as long-afterglow materials.

[0069] The beneficial effects that this application can produce include: (1) The rare earth doped crystal provided by the present invention, as a fluorescent scintillation material, exhibits photoluminescence and scintillation of various colors visible to the naked eye under ultraviolet light and X-ray irradiation, and can be used to make fluorescent materials, high-energy radiation detection materials and devices, etc.

[0070] (2) The crystal provided by this invention has good thermal stability and excellent X-ray scintillation performance. Experiments have determined that the upper limit of thermal stability of this type of scintillation material is as high as 270℃, and the rare earth doped compound [Gd]... 0.96 (BDC) 1.5 (DMA)] n 4% Tb 3+ The scintillation intensity is approximately 19.2 times that of bismuth germanate (BGO) scintillation crystals, and the rare-earth-doped compound [Gd]... 0.98 (BDC) 1.5 (DMA)] n 2%Eu 3+ The scintillation intensity is approximately 6.8 times that of BGO, and it overcomes the drawbacks of heavy metal pollution and high industrial energy consumption inherent in traditional commercial scintillators, making it of significant commercial application value in the field of scintillation materials. The crystal provided by this invention exhibits excellent X-ray response sensitivity and irradiation stability.

[0071] (3) The rare-earth-doped material according to this application can be used as an X-ray scintillation material to achieve X-ray scintillation detection with high sensitivity, low detection limit, and stable optical response. Rare-earth-doped compound [Gd] 0.96 (BDC) 1.5 (DMA)] n 4% Tb 3+ and rare earth doped compounds [Gd 0.98 (BDC) 1.5 (DMA)] n 2% Eu 3+ It possesses sensitive X-ray detection capabilities, with detection limits as low as 93.4 nGy / s and 0.45 μGy / s, both lower than the conventional medical diagnostic dose standard of 5.50 μGy / s. The scintillation outputs are 22074 and 6062 photons / MeV, respectively. The high scintillation output and low X-ray detection limit of this rare-earth scintillation material can further improve the spatial resolution of imaging display devices, which is crucial for high-quality imaging, making it of significant commercial application value in the field of high-energy particle detection and imaging display materials.

[0072] (4) The rare earth doped material according to this application can be used as a long afterglow information encryption material, rare earth doping [Gd 1-x% (BDC) 1.5 (DMA)] n :x% Tb 3+ The afterglow duration of the crystalline material under 365nm ultraviolet light is adjustable (0-4.5 s); rare earth doping [Gd] 1-x% (BDC) 1.5 (DMA)] n :x% Eu 3+The afterglow duration of the crystal material under 365nm ultraviolet light is adjustable (0-2s). The above-mentioned crystal material can achieve anti-counterfeiting encryption of multiple logical information such as emission color, afterglow duration, and spatial information.

[0073] (5) The crystal preparation method provided by the present invention is simple, and the crystal obtained is of high purity and good crystallinity as a fluorescent, scintillation and long afterglow material, which is suitable for large-scale industrial production.

[0074] (6) The method for preparing rare earth-doped crystals with both long afterglow and high photoluminescence quantum yield provided by the present invention has a simple design strategy, the prepared rare earth-doped crystals have obvious long afterglow emission, high photoluminescence quantum yield, and are universal. Attached Figure Description

[0075] Figure 1 It is sample #1 crystal material [Gd(BDC)] 1.5 (DMA)] n A schematic diagram of the coordination environment.

[0076] Figure 2 It is sample #1 crystal material [Gd(BDC)] 1.5 (DMA)] n X-ray powder diffraction pattern.

[0077] Figure 3 It is sample #2 crystal material [Gd 0.96 (BDC) 1.5 (DMA)] n 4% Tb 3+ Photoluminescence spectrum.

[0078] Figure 4 It is sample #2 crystal material [Gd 0.96 (BDC) 1.5 (DMA)] n 4% Tb 3+ and sample #3 crystal material [Gd 0.98 (BDC) 1.5 (DMA)] n 2% Eu 3+ The luminous color coordinate diagram.

[0079] Figure 5 It is sample #2 crystal material [Gd 0.96 (BDC) 1.5 (DMA)] n 4% Tb 3+ Photoluminescence quantum yield diagram.

[0080] Figure 6 It is sample #2 crystal material [Gd0.96 (BDC) 1.5 (DMA)] n 4% Tb 3+ The fluorescence lifetime spectrum.

[0081] Figure 7 Sample #2 crystal material [Gd] was tested at the same X-ray dose rate. 0.96 (BDC) 1.5 (DMA)] n 4% Tb 3 + LYSO:Ce, BGO and sample #3 crystal material [Gd 0.98 (BDC) 1.5 (DMA)] n 2% Eu 3+ Comparison of scintillation emission spectra.

[0082] Figure 8 It is sample #2 crystal material [Gd 0.96 (BDC) 1.5 (DMA)] n 4% Tb 3+ Linear graph of scintillation intensity as a function of X-ray dose.

[0083] Figure 9 It is sample #2 crystal material [Gd 0.96 (BDC) 1.5 (DMA)] n 4% Tb 3+ X-ray detection limit diagram.

[0084] Figure 10 It is sample #1 crystal material [Gd(BDC)] 1.5 (DMA)] n Thermogravimetric curve.

[0085] Figure 11 It is sample #2 crystal material [Gd 0.96 (BDC) 1.5 (DMA)] n 4% Tb 3+ and sample #3 crystal material [Gd 0.98 (BDC) 1.5 (DMA)] n 2% Eu 3+ Thermogravimetric curve.

[0086] Figure 12 It is sample #3 crystal material [Gd 0.98 (BDC) 1.5 (DMA)] n 2% Eu3+ Photoluminescence spectrum.

[0087] Figure 13 It is sample #3 crystal material [Gd 0.98 (BDC) 1.5 (DMA)] n 2% Eu 3+ Photoluminescence quantum yield diagram.

[0088] Figure 14 It is sample #3 crystal material [Gd 0.98 (BDC) 1.5 (DMA)] n 2% Eu 3+ The fluorescence lifetime spectrum.

[0089] Figure 15 It is sample #3 crystal material [Gd 0.98 (BDC) 1.5 (DMA)] n 2% Eu 3+ Linear graph of scintillation fluorescence intensity as a function of X-ray dose.

[0090] Figure 16 It is sample #3 crystal material [Gd 0.98 (BDC) 1.5 (DMA)] n 2% Eu 3+ X-ray detection limit diagram.

[0091] Figure 17 It is sample #2 crystal material [Gd 0.96 (BDC) 1.5 (DMA)] n 4% Tb 3+ and sample #3 crystal material [Gd 0.98 (BDC) 1.5 (DMA)] n 2% Eu 3+ Irradiation stability diagram.

[0092] Figure 18 Different doped Tb 3+ Sample #1 of the proportion of crystal material [Gd 1-x% (BDC) 1.5 (DMA)] n :x% Tb 3+ The photo shows the afterglow of the setting sun.

[0093] Figure 19 Different doped Eu 3+ Sample #1 of the proportion of crystal material [Gd 1-x% (BDC)1.5 (DMA)] n :x% Eu 3+ The photo shows the afterglow of the setting sun. Detailed Implementation

[0094] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0095] Experimental methods not specified in the following examples are generally performed under standard conditions or as recommended by the manufacturer.

[0096] Unless otherwise specified, the raw materials and reagents used in the embodiments of this application were all purchased commercially.

[0097] The analytical measuring instruments used in the embodiments of this application are as follows: Single-crystal structure characterization: collected on a Rigaku FR-X type single-crystal diffractometer, Mo target, K α Radiation source ( λ =0.7107nm), tested at 273 K.

[0098] Thermogravimetric analysis: performed using a METTLER TOLEDO thermogravimetric analyzer.

[0099] Photoluminescence spectroscopy, quantum yield, and decay lifetime: performed using an FLS1000 fluorescence spectrometer.

[0100] Scintillation performance (scintillation intensity, X-ray detection limit, and X-ray irradiation stability) was determined on an X-ray scintillation spectrometer.

[0101] XRD: Performed using a Rigaku Miniflex 600 X-ray diffractometer.

[0102] Example 1 Gd(NO3)3(H2O)6 (0.1 mmol) and terephthalic acid (0.1 mmol) were placed in a 10 mL glass vial in a 1:1 molar ratio. Then, DMA (3 mL), water (2 mL), and HCl (0.1 mL) were added as solvent. The mixture was placed in a sealed container and reacted at 100°C. o At C, the reaction time was 48 h. After the reaction was completed, the mixture was cooled to room temperature, filtered, and washed with DMA and ethanol to obtain colorless, transparent blocky crystals [Gd(BDC)]. 1.5 (DMA)] n This is designated as sample #1.

[0103] Example 2 Gd(NO3)3(H2O)6 (0.096 mmol), Tb(NO3)3(H2O)6 (0.004 mmol), and terephthalic acid (0.1 mmol) were placed in a 10 mL glass vial in a molar ratio of 0.96:0.04:1. Then, DMA (3 mL), water (2 mL), and HCl (0.1 mL) were added as solvents. The mixture was placed in a sealed container and reacted at 100 °C. o C, the reaction time was 48 h, after which the mixture was cooled to room temperature, filtered, and washed with DMA and ethanol to obtain colorless, transparent blocky crystals [Gd]. 0.96 (BDC) 1.5 (DMA)] n 4% Tb 3+ This is designated as sample #2.

[0104] Example 3 Gd(NO3)3(H2O)6 (0.098 mmol), Eu(NO3)3(H2O)6 (0.002 mmol), and terephthalic acid (0.1 mmol) were placed in a 10 mL glass vial in a molar ratio of 0.98:0.02:1. Then, DMA (3 mL), water (2 mL), and HCl (0.1 mL) were added as solvents. The mixture was placed in a sealed container and reacted at 100 °C. o C, the reaction time was 48 h, after which the mixture was cooled to room temperature, filtered, and washed with DMA and ethanol to obtain colorless, transparent blocky crystals [Gd]. 0.98 (BDC) 1.5 (DMA)] n 2% Eu 3+ This is designated as sample #3.

[0105] Example 4 Gd(NO3)3(H2O)6 (0.099 mmol), Tb(NO3)3(H2O)6 (0.001 mmol), and terephthalic acid (0.1 mmol) were placed in a 10 mL glass vial in a molar ratio of 0.99:0.01:1. Then, DMA (3 mL), water (2 mL), and HCl (0.1 mL) were added as solvents. The mixture was placed in a sealed container and reacted at 100 °C. o C, the reaction time was 48 h, after which the mixture was cooled to room temperature, filtered, and washed with DMA and ethanol to obtain colorless, transparent blocky crystals [Gd]. 0.99 (BDC) 1.5 (DMA)] n 1% Tb 3+ This is designated as sample #4.

[0106] Example 5 Gd(NO3)3(H2O)6 (0.097 mmol), Tb(NO3)3(H2O)6 (0.003 mmol), and terephthalic acid (0.1 mmol) were placed in a 10 mL glass vial in a molar ratio of 0.97:0.03:1. Then, DMA (3 mL), water (2 mL), and HCl (0.1 mL) were added as solvents. The mixture was placed in a sealed container and reacted at 100 °C. o C, the reaction time was 48 h, after which the mixture was cooled to room temperature, filtered, and washed with DMA and ethanol to obtain colorless, transparent blocky crystals [Gd]. 0.97 (BDC) 1.5 (DMA)] n 3% Tb 3+ This is designated as sample #5.

[0107] Example 6 Gd(NO3)3(H2O)6 (0.099 mmol), Eu(NO3)3(H2O)6 (0.001 mmol), and terephthalic acid (0.1 mmol) were placed in a 10 mL glass vial in a molar ratio of 0.99:0.01:1. Then, DMA (3 mL), water (2 mL), and HCl (0.1 mL) were added as solvents. The mixture was placed in a sealed container and reacted at 100 °C. o C, the reaction time was 48 h, after which the mixture was cooled to room temperature, filtered, and washed with DMA and ethanol to obtain colorless, transparent blocky crystals [Gd]. 0.99 (BDC) 1.5 (DMA)] n 1% Eu 3+ This is designated as sample #6.

[0108] Example 7 Gd(NO3)3(H2O)6 (0.0995 mmol), Eu(NO3)3(H2O)6 (0.0005 mmol), and terephthalic acid (0.1 mmol) were placed in a 10 mL glass vial in a molar ratio of 0.995:0.005:1. Then, DMA (3 mL), water (2 mL), and HCl (0.1 mL) were added as solvents. The mixture was placed in a sealed container and reacted at 100 °C. o C, the reaction time was 48 h, after which the mixture was cooled to room temperature, filtered, and washed with DMA and ethanol to obtain colorless, transparent blocky crystals [Gd]. 0.995 (BDC) 1.5 (DMA)] n 0.5% Eu 3+ This is designated as sample #7.

[0109] Test Example 1 [Gd(BDC)] 1.5 (DMA)] n Structural characterization of crystalline materials The structure of sample #1 prepared in Example 1 was characterized.

[0110] Sample #1[Gd(BDC)] 1.5 (DMA)] n X-ray single-crystal diffraction tests were performed on a Rigaku FR-X single-crystal diffractometer (test conditions: Mo target, K α Radiation source ( λ = 0.07107 nm), after testing at 293 K, via Olex 2 1.5 Analyze the structure.

[0111] X-ray single-crystal diffraction analysis results show that the crystalline material structure of sample #1 is [Gd(BDC)]. 1.5 (DMA)] n It belongs to the monoclinic crystal system. P–1 Space group. Cell parameters are a = 9.7360(4) Å, b = 10.4585(5) Å, c =10.6106(5) Å, α = 93.327(4)°, β = 114.361(4)°, γ = 116.987(4)°, Z = 1, V = 836.07(9) Å 3 .

[0112] The crystal material of sample #1 is [Gd(BDC)]. 1.5 (DMA)] n A schematic diagram of the coordination environment is shown below. Figure 1 As shown, the smallest asymmetric structural unit contains 1 Gd 3+ Metal ions, 1.5 BDC 2– The ligand and one coordinated DMA molecule.

[0113] Gd 3+ The metal ion is coordinated with 8 oxygen atoms, and each is associated with one of the 4 BDCs. 2– The ligand has 7 O atoms on its carboxylate group and 1 O atom from the coordinated DMA molecule.

[0114] The X-ray powder diffraction pattern of sample #1 is as follows: Figure 2As shown, the experimental results (1 represents sample #1) are consistent with the simulation results (simulation line), indicating that the material is a pure phase, i.e., a Gd-based crystal [Gd(BDC)]. 1.5 (DMA)] n .

[0115] Samples #2, #3, #4, and #5 were tested using the same method as described above. The X-ray single-crystal diffraction analysis results of samples #2, #3, #4, and #5 were consistent with those of sample #1; the XRD test results of samples #2, #3, #4, and #5 were consistent with those of sample #1.

[0116] Test Example 2: Rare Earth Doping [Gd] 0.96 (BDC) 1.5 (DMA)] n 4% Tb 3+ Photoluminescence performance testing of crystalline materials The photoluminescence performance of sample #2 prepared in Example 2 was tested.

[0117] Sample #2 [Gd 0.96 (BDC) 1.5 (DMA)] n 4% Tb 3+ The photoluminescence properties of the crystalline materials were tested on an Edinburgh FL1000. Excitation and emission spectra are shown below. Figure 3 As shown, under optimal wavelength excitation of 310 nm, the compound exhibits green light emission at 488, 542, 582, and 620 nm. The RGB color coordinates of this luminescent crystal material, calculated from the fluorescence color coordinates, are (0.299, 0.610) (e.g., ...). Figure 4 As shown). By Figure 5 As can be seen, the photoluminescence quantum yield (PLQY) of sample 1 is as high as 78.78%. Such a high quantum yield is uncommon in rare earth complexes.

[0118] The luminescence lifetime was tested using a microsecond lamp and PMT detector from an Edinburgh FL1000. The luminescence lifetime and fitting curve are shown below. Figure 6 As shown, the luminescence lifetime test indicates that sample #2 [Gd 0.96 (BDC) 1.5 (DMA)] n 4% Tb 3+ The lifetime of the crystalline material is 1.418 ms, which is in the millisecond range.

[0119] Samples #4 and #5 were tested using the same method as described above. The photoluminescence performance test results of samples #4 and #5 were consistent with those of sample #2.

[0120] Test Example 3 [Gd]0.96 (BDC) 1.5 (DMA)] n 4% Tb 3+ Scintillation performance testing of crystalline materials The scintillation performance of sample #2 prepared in Example 2 was tested.

[0121] Sample #2 [Gd 0.96 (BDC) 1.5 (DMA)] n 4% Tb 3+ The scintillation emission test of the crystalline material was performed on an X-ray scintillation spectrometer. The main part of the instrument is the X-ray scintillation spectrometer, where the excitation source is a high-purity tungsten target (model: Moxtek® MAGPRO X-ray sources). The scintillation emission spectrum is shown below. Figure 7 Under constant tube voltage and different tube current X-ray irradiation, the compounds all exhibited scintillation signals at 488, 542, 582, and 620 nm. Characterization of the scintillation performance of sample #2 showed that its scintillation intensity was significantly higher than that of commercial scintillators LYSO:Ce and BGO (e.g., ...). Figure 7 (As shown). The linear spectrum of scintillation intensity as a function of X-ray dose is shown in the figure. Figure 8 As the X-ray dose increases, the scintillation signal intensity increases linearly, indicating high sensitivity to X-rays. Furthermore, Figure 9 The detection limit of sample 1 was 93.4 nGy / s, which is about 60 times lower than the detection limit of 5.5 μGy / s required for commercial medical diagnostics.

[0122] Samples #4 and #5 were tested using the same method as described above. The flickering performance test results of samples #4 and #5 were consistent with those of sample #2.

[0123] Test Example 4 [Gd(BDC)] 1.5 (DMA)] n Crystal materials and rare earth-doped crystals [Gd 1-x% (BDC) 1.5 (DMA)] n :x%Ln 3+ Thermal stability test Thermogravimetric analysis was performed on sample #1, and the results are as follows: Figure 10 As shown. By Figure 10 As can be seen, sample #1 remains stable below approximately 278℃, demonstrating excellent thermal stability.

[0124] Thermogravimetric analysis was performed on samples #2 and #3, and the results are as follows: Figure 11 As shown. By Figure 11It can be seen that both samples #2 and #3 remain stable below approximately 279°C, demonstrating excellent thermal stability.

[0125] Samples #4, #5, #6, and #7 were tested using the same method as described above. The thermal stability test results for samples #4, #5, #6, and #7 were consistent with those for samples #2 and #3.

[0126] Test Example 5: Rare Earth Doping [Gd] 0.98 (BDC) 1.5 (DMA)] n 2% Eu 3+ Photoluminescence performance testing of crystalline materials The photoluminescence properties of sample #3 prepared in Example 3 were tested.

[0127] Sample #3 [Gd 0.98 (BDC) 1.5 (DMA)] n 2% Eu 3+ The photoluminescence properties of the crystalline materials were tested on an Edinburgh FL1000.

[0128] Excitation and emission spectra such as Figure 12 As shown, under optimal wavelength excitation of 300 nm, the compound exhibits red light emission at 590, 613, 654, and 700 nm. The RGB color coordinates of this red-emitting crystal material, calculated from the fluorescence color coordinates, are (0.660, 0.338) (e.g., ...). Figure 4 As shown). By Figure 13 As can be seen, the photoluminescence quantum yield (PLQY) of sample #3 is as high as 72.88%.

[0129] The luminescence lifetime was tested using a microsecond lamp and PMT detector from an Edinburgh FL1000. The luminescence lifetime and fitting curve are shown below. Figure 14 As shown, the luminescence lifetime test indicates that sample #3 [Gd 0.98 (BDC) 1.5 (DMA)] n 2% Eu 3+ The lifetime of the crystalline material is 1.297 ms, which is in the millisecond range.

[0130] Samples #6 and #7 were tested using the same method as described above. The photoluminescence performance test results of samples #6 and #7 were consistent with those of sample #3.

[0131] Test Example 6: Rare Earth Doping [Gd] 0.98 (BDC) 1.5 (DMA)] n 2% Eu3+ Scintillation performance testing of crystalline materials The scintillation performance of sample #3 prepared in Example 3 was tested.

[0132] Sample #3 [Gd] 0.98 (BDC) 1.5 (DMA)] n 2% Eu 3+ The scintillation emission test of the crystalline material was performed on an X-ray scintillation spectrometer. The main part of the instrument was an Edinburgh FLS 1000 fluorescence spectrometer, with a high-purity tungsten target (model: Moxtek® MAGPRO X-ray sources) as the excitation source. The scintillation emission spectrum is shown below. Figure 7 Under X-ray irradiation with constant tube voltage and different tube currents, the compound exhibited scintillation signals at 589, 612, 652, and 700 nm. The linear spectrum of scintillation intensity as a function of X-ray dose is shown below. Figure 15 The scintillation signal intensity increases linearly with increasing X-ray dose. Additionally, Figure 16 The detection limit of sample #3 was 0.45 μGy / s, which is lower than the requirement of 5.5 μGy / s for commercial medical diagnostics.

[0133] Samples #6 and #7 were tested using the same method as described above. The flicker luminescence performance test results of samples #6 and #7 were consistent with those of sample #3.

[0134] Test Example 7: Rare Earth Doping [Gd] 1-x% (BDC) 1.5 (DMA)] n :x% Ln 3+ Irradiation stability testing of crystalline materials The irradiation stability of sample #2 prepared in Example 2 was tested.

[0135] Sample #2 [Gd 0.96 (BDC) 1.5 (DMA)] n 4% Tb 3+ The irradiation stability of crystalline materials was tested using an X-ray scintillation spectrometer. Samples were irradiated with continuous high-dose-rate X-rays, and their luminescence intensity was recorded. Figure 17 As shown, under at least 3 hours of continuous X-ray irradiation (irradiation conditions: X-ray tube voltage 50 kV, X-ray dose rate 42.29 mGy / s), the scintillation performance of sample #2 did not decrease significantly, indicating that it has good irradiation stability.

[0136] The irradiation stability of sample #3 prepared in Example 3 was tested.

[0137] Sample #3 [Gd] 0.98 (BDC) 1.5 (DMA)] n 2% Eu 3+ The irradiation stability of crystalline materials was tested using an X-ray scintillation spectrometer. Samples were irradiated with continuous high-dose-rate X-rays, and their luminescence intensity was recorded. Figure 17 As shown, under at least 3 hours of continuous X-ray irradiation (irradiation conditions: X-ray tube voltage 50 kV, X-ray dose rate 42.29 mGy / s), the scintillation performance of sample #3 did not decrease significantly, indicating that it has good irradiation stability.

[0138] Samples #4, #5, #6, and #7 were tested using the same method as described above. The irradiation stability test results for samples #4, #5, #6, and #7 were consistent with those for samples #2 and #3.

[0139] Test Example 8: Rare Earth Doping [Gd] 1-x% (BDC) 1.5 (DMA)] n :x% Ln 3+ Afterglow duration test of crystalline materials Samples #2 and #3 prepared in Examples 2 and 3, as well as other Ln samples, were compared. 3+ Afterglow duration was tested on crystal materials with varying doping ratios. The crystal samples were irradiated at close range with a 365 nm UV lamp for 1 minute, and afterglow emission images of the crystal materials were taken under UV lamp irradiation and after the UV light was removed (e.g., [images of afterglow emission under UV lamp irradiation and after UV light removal]). Figure 18 and Figure 19 (As shown).

[0140] The rare earth doping [Gd] 1-x% (BDC) 1.5 (DMA)] n :x% Tb 3+ The afterglow duration of the crystalline material can be 0-4.5 s. The rare-earth doped [Gd] 1-x% (BDC) 1.5 (DMA)] n :x% Eu 3+ The afterglow duration of crystalline materials can be 0-2 seconds, indicating their significant long afterglow luminescence characteristics.

[0141] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A crystal, characterized in that, The chemical formula of the crystal is [Gd(L) 1.5 (DMA) n Equation I; In formula I, L is a ligand formed from deprotonated benzene polycarboxylic acids; The benzene polycarboxylic acid is selected from any one of terephthalic acid, phthalic acid, and isophthalic acid; DMA is N , N -Dimethylacetamide; n The value ∞ indicates that it is repeated and extended infinitely.

2. The crystal according to claim 1, characterized in that, The crystal has a three-dimensional framework structure; The smallest asymmetric structural unit of the three-dimensional structure contains 1.5 L... 2– ligand, 1 Gd 3+ Metal ions, 1 DMA molecule; Gd is an octagonal configuration of Gd. 3+ Metal ions; The Gd 3+ Metal ions react with four L... 2– The seven O atoms on the carboxylate group of the ligand are coordinated with one O atom on the DMA.

3. The crystal according to claim 1, characterized in that, When L is a ligand formed from deprotonated terephthalic acid, the crystal belongs to the triclinic crystal system and has... P–1 Spatial group structure; Preferably, the unit cell parameters of the crystal are: a = 9.7~9.8Å, b = 10.4~10.5Å, c = 10.5~10.7Å, α = 93~94°, β = 114~115°, γ = 116~118°, Z = 1, V = 830~840Å 3 ; Preferably, a = 9.72~9.75Å, b = 10.45~10.47Å, c = 10.59~10.62 Å, α = 93.1~93.5°, β = 114.1~114.5°, γ = 116.5~117.2°, V = 833~838Å 3 ; More preferably, α = 93.17~93.38°, β = 114.28~114.39°, γ = 116.93~117.02°.

4. The crystal according to claim 1, characterized in that, The crystal is rare-earth doped, and the chemical formula of the rare-earth doped crystal is: [Gd 1-x% (L) 1.5 (DMA) n :x% Ln 3+ Formula II; In formula II, x=0.1 ~ 10； Ln 3+ Selected from Tb 3+ Or Eu 3+ Any one of them.

5. The crystal according to any one of claims 1 to 4, characterized in that, The thermal decomposition temperature of the crystal is ≥200℃; Preferably, the thermal decomposition temperature of the crystal is ≥270℃.

6. The crystal according to claim 4, characterized in that, The luminescence lifetime of the rare-earth-doped crystal is 1.0~4.0 ms; Preferably, the luminescence lifetime of the rare earth-doped crystal is 1.10~2.50 ms; More preferably, the luminescence lifetime of the rare earth-doped crystal is 1.20~1.50 ms; Preferably, when it is Tb 3+ When doped, Tb 3+ Doped rare earth crystals emit green light when irradiated with ultraviolet light or X-rays; Preferably, the Tb 3+ The RGB color coordinates of the green light of the doped rare earth crystal are (0.29~0.31, 0.61~0.63); Preferably, the Tb 3+ The RGB color coordinates of the green light of the doped rare earth crystal are (0.295~0.305, 0.618~0.625). Preferably, when it is Eu 3+ When doped, Eu 3+ Doped rare earth crystals emit red light when irradiated with ultraviolet light or X-rays; Preferably, the Eu 3+ The RGB color coordinates of the red light of the doped rare earth crystal are (0.65~0.66, 0.33~0.34); Preferably, the Eu 3+ The RGB color coordinates of the red light of the doped rare earth crystal are (0.652~0.658, 0.335~0.337). Preferably, the Tb 3+ Or Eu 3+ The doped rare earth crystals emit a green afterglow after being irradiated with ultraviolet light.

7. The method for preparing the crystal according to any one of claims 1 to 6, characterized in that, A mixed solution containing benzene polycarboxylic acid, a metal source, and a solvent is placed in a sealed container and reacted to obtain the crystals. The metal source is a Gd metal source, or The metal source is a Gd metal source and an Ln metal source, where Ln is selected from Tb or Eu. The solvent includes DMA.

8. The preparation method according to claim 7, characterized in that, The Gd metal source is selected from at least one of Gd(NO3)3, Gd(CH3COO)3, and GdCl3; The Tb metal source is selected from at least one of Tb(NO3)3, Tb(CH3COO)3, and TbCl3, and the Eu metal source is selected from at least one of Eu(NO3)3, Eu(CH3COO)3, and EuCl3; Preferably, the molar ratio of the metal source to the benzene polycarboxylic acid is 1:1; The molar amount of the metal source is expressed as the molar amount of the metal element in the metal source; Preferably, the solvent includes at least one of DMA, water, methanol, and ethanol, and a hydrogen halide solution; Preferably, the total ratio of the metal source to the solvent is 0.1 mmol: 3~8 mL; Preferably, the ratio of the metal source to DMA is 0.1 mmol: 3~5 mL.

9. The preparation method according to claim 7, characterized in that, The reaction temperature is 80~140℃, and the reaction time is 24~72 hours; Preferably, the reaction temperature is 90~120℃ and the reaction time is 36~54 hours.

10. The application of the crystal according to any one of claims 1 to 6 in light-emitting diodes, X-ray detection materials, radiation detection dosimeters, radiation imaging devices, long-afterglow luminescent materials, and information anti-counterfeiting encryption.

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