Synthesis of supramolecular scintillator and application of supramolecular scintillator in single crystal X-ray imaging

Abstract

The invention discloses a low-dimensional organic-alkali metal-copper (I) halide supramolecular scintillator based on crown ether assisted self-assembly, a synthesis method thereof and application of the low-dimensional organic-alkali metal-copper (I) halide supramolecular scintillator in single crystal X-ray imaging. A series of supramolecular scintillators are successfully synthesized by adopting a supramolecular coordination strategy of crown ether (L) and alkali metal ions (M) and a saturated solution volatilization method. By optimizing the crown ether coordination mode, controllable preparation of large-size single crystals is achieved, the optical and X-ray imaging performance of the large-size single crystals is improved, a new thought is provided for research and development of novel high-performance X-ray scintillators, and the application potential of the supramolecular scintillators in the field of high-resolution single crystal X-ray imaging is expanded.

Description

Technical Field

[0001] The present invention belongs to the field of organic functional materials, and particularly relates to a large-sized organic-alkali metal-copper(I) halide supramolecular scintillator assisted by crown ethers (18-crown-6, dibenzo-24-crown-8, 24-crown-8, dibenzo-18-crown-6, benzo-18-crown-6, 15-crown-5, benzo-15-crown-5, dibenzo-15-crown-5, 12-crown-4, benzo-12-crown-4) self-assembly, its synthesis method and its application in single crystal X-ray imaging. Background Art

[0002] As an important technology in the fields of modern science, medical diagnosis and industrial inspection, one of the core components of X-ray imaging is an efficient scintillator material. Traditional inorganic scintillators (such as CsI:Tl, Bi4Ge3O 12 , BGO) are widely used in commercial applications due to their high X-ray absorption coefficient and excellent attenuation efficiency. However, such materials generally have problems such as high manufacturing cost, complex preparation process and uncontrollable luminescence color, which limit their further application in high-resolution X-ray imaging. In recent years, perovskite scintillators have attracted much attention due to their solution processability, tunable luminescence color and high light yield. However, most perovskite materials contain lead, resulting in problems such as environmental pollution and poor stability. Therefore, the development of lead-free halide scintillators shows great potential in terms of environmental protection, stability and scalability, and at the same time has excellent optoelectronic properties, providing new possibilities for efficient X-ray imaging, and has become the focus of current research.

[0003] Compared with traditional inorganic scintillators, organic-copper(I) halide scintillators have attracted much attention due to their low toxicity, high X-ray attenuation ability and nearly 100% photoluminescence quantum yield. Such materials not only have a higher light yield, but also have a lower synthesis cost, providing a new solution for X-ray scintillation applications. However, existing synthesis methods (such as polymer doping, extrusion casting) often damage the ordered lattice structure of the scintillator, resulting in enhanced light scattering, decreased material stability and reduced imaging resolution, thus limiting their practical application in high-resolution X-ray imaging. Therefore, how to ensure the structural integrity and imaging accuracy while improving the material stability and optical properties has become an urgent problem to be solved.

[0004] In recent years, the application of supramolecular chemistry in the field of optoelectronic functional materials has gradually attracted attention. The selection of ligands plays a crucial role in the structural stability, luminescence efficiency, and environmental tolerance of organic-copper(I) halide scintillators. However, common ligand schemes still have limitations: N-ligands tend to cause structural instability, S-ligands are prone to oxidation, and the synthesis process of P-ligands is complex, restricting large-scale production. Crown ethers possess precise ion selectivity, excellent lattice stability, and enhanced environmental tolerance, showing excellent performance in organic-metal halide luminescent materials. Meanwhile, they are easily synthesized, have high cost-effectiveness and good scalability, and are expected to become an ideal regulation strategy. Summary of the Invention

[0005] In view of the limitations of existing scintillator materials in X-ray imaging, the present invention provides a method for synthesizing a novel large-sized organic-alkali metal-copper(I) halide supramolecular scintillator single crystal. The obtained supramolecular scintillator single crystal can be successfully applied to high-resolution single crystal X-ray imaging, broadening the application of supramolecular scintillator materials in high-resolution single crystal X-ray imaging.

[0006] To achieve the above object, the present invention adopts the following technical solutions: A supramolecular scintillator, whose structural general formula is: (L) x @M y (S) z Cu m X n , wherein, L is selected from any one of 18-crown-6-ether (18C6), dibenzo-24-crown-8-ether (dibenzo 24C8), 24-crown-8-ether (24C8), dibenzo-18-crown-6-ether (dibenzo 18C6), benzo-18-crown-6-ether (benzo 18C6), 15-crown-5-ether (15C5), benzo 15-crown-5-ether (benzo 15C5), dibenzo 15-crown-5-ether (dibenzo 15C5), 12-crown-4-ether (12C4), benzo 12-crown-4-ether (benzo 12C4), and is used to form a stable supramolecular coordination structure with alkali metal ion M; M is selected from any one of alkali metal ions Li + , Na + , K + , Rb + , Cs + to match different crown ether coordination modes and ensure structural stability; S is derived from absorbed water (H2O) in the air or at least one of hypophosphorous acid (H3PO2) and acetone (CH3COCH3) as a solvent, and is used to regulate the crystal structure and growth environment; X is selected from halide ions F - , Cl - , Br - , I- Any one of them is used to meet different optical and electrical property requirements; x is selected from 1, 2 or 3, corresponding to the coordination number of the crown ether; y is selected from 1 or 2 and is related to x; z is selected from 0, 1, 2 or 3, indicating the solvent molecule content in the system; m is selected from 1, 2, 3, 4 or 5, indicating the number of Cu atoms; n = y + m, indicating the total number of halide ions coordinated with L and Cu to satisfy the charge balance relationship and ensure a stable Cu-I coordination structure.

[0007] Preferably, when L is selected from 18-crown-6 and M is selected from Na + 、K + or Cs + , for obtaining three kinds of supramolecular scintillators, specifically, the double-crown structure (18C6)2@Na2(H2O)3Cu4I6 (CNCI, x = 2, y = 2, z = 3, m = 4, n = 6), the single-crown structure (18C6)@KCuI2 (CKCI, x = 1, y = 1, z = 0, m = 1, n = 2), and the triple-crown structure (18C6)3@Cs2Cu2I4 (CCCI, x = 3, y = 2, z = 0, m = 2, n = 4).

[0008] The preparation method of the supramolecular scintillator includes the following steps: 1) Weigh the crown ether compound L, the alkali metal halide MX and the copper halide CuX in proportion, and place them in a ball mill for grinding for 15 minutes to make them fully and evenly mixed; 2) Dissolve the ground mixture in a solvent, stir until completely dissolved, and filter to remove insoluble impurities (to ensure the purity of crystal growth) to obtain a clear precursor solution; 3) Transfer the obtained precursor solution to a glass bottle, and slowly evaporate the solvent by the solvent evaporation crystallization method at room temperature; 4) After standing for 3 - 30 days, transparent single crystals precipitate at the bottom of the bottle, and large-sized supramolecular scintillators are obtained.

[0009] Preferably, the preparation of the above-mentioned CNCI, CKCI, and CCCI includes the following steps: 1) Accurately weigh 18C6, the alkali metal iodide (NaI, KI or CsI) and CuI in a molar ratio of 2:1:1, and place them in a ball mill for grinding for 15 minutes to make them fully and evenly mixed; 2) Dissolve the ground mixture in a mixed solution of hypophosphorous acid and acetone (volume ratio 1:20), stir until completely dissolved, and filter to remove insoluble impurities to obtain a clear precursor solution; 3) Transfer the obtained precursor solution to a glass bottle, and slowly evaporate the solvent by the solvent evaporation crystallization method at room temperature; 4) After standing for 3 days, transparent single crystals precipitate at the bottom of the bottle. Among them, CNCI is a yellow transparent granular crystal; CKCI is a colorless transparent rod-shaped crystal; CCCI is a colorless transparent block crystal.

[0010] Furthermore, centimeter-scale CCCI single crystals can be prepared by controlling the crystal growth environment. The specific steps are as follows: 1) Weigh 18C6 (0.05 mol), CsI (0.025 mol), and CuI (0.025 mol) respectively, and place them in a ball mill for grinding for 15 minutes; 2) Dissolve the ground mixture in a mixed solution of hypophosphorous acid and acetone (volume ratio 1:20), stir until completely dissolved, and filter to remove insoluble impurities to obtain a clear precursor solution; 3) Transfer the obtained precursor solution to a beaker, and slowly evaporate the solvent by the solvent evaporation crystallization method under a constant temperature environment of 21 °C; 4) After standing for 30 days, centimeter-scale, colorless transparent block single crystals precipitate at the bottom of the beaker.

[0011] Even further, the obtained centimeter-scale CCCI single crystals can be surface-treated to improve their optical properties and X-ray imaging properties. The steps include: 1) Add the obtained centimeter-scale CCCI single crystal (initial thickness of about 6 mm) to glycerol to wrap its surface with glycerol to reduce surface damage and prevent the generation of lattice defects; 2) Gradually polish it with 5000 - 20000 mesh ultra-fine sandpaper to ensure that the surface of the material is uniformly smooth and reduce light scattering loss; 3) Finally, control the thickness of the single crystal to 0.94 mm so that it exhibits excellent optical transmittance in both the visible light and X-ray ranges.

[0012] This polishing strategy can effectively improve the surface quality of the single crystal, reduce light scattering, improve imaging clarity, and maintain high stability and high spatial resolution under X-ray irradiation, ensuring a clearer imaging effect in high-precision X-ray imaging applications.

[0013] In the present invention, a stable supramolecular coordination structure is formed through the synergistic effect of crown ether and alkali metal ions, and combined with the coordination characteristics of different copper(I) halides (CuX, X = F - 、Cl - 、Br - 、I - ), the structure regulation and optical property optimization of the material are realized. Compared with traditional scintillator materials, applying the supramolecular scintillator of the present invention in X-ray imaging has high light yield, low detection limit, and excellent stability, and is suitable for high-resolution medical imaging, industrial non-destructive testing, and radiation safety monitoring and other fields.

[0014] The beneficial effects of the present invention are as follows: 1) The present invention synthesizes a novel low-dimensional organic-copper(I) halide scintillator by using a crown ether-assisted self-assembly strategy. This strategy significantly improves the lattice stability and environmental tolerance of the material, and successfully prepares centimeter-scale transparent single crystals (transmittance > 80%) by a room-temperature solution method, greatly enhancing the practicality of the material.

[0015] 2) The scintillator prepared by the present invention exhibits excellent photoluminescence properties. Among them, the photoluminescence quantum yield of the obtained CCCI is as high as 99.4%, mainly due to the coordination effect of crown ether and the synergistic effect of copper-halide clusters. This effect promotes the localization of excitons, stabilizes the self-trapped exciton state, and effectively inhibits non-radiative loss, achieving a nearly uniform luminescence efficiency.

[0016] 3) The CCCI single crystal obtained by the present invention exhibits excellent performance in X-ray scintillation applications, with a radiation luminescence yield as high as 71000 photons MeV -1 , and the minimum detectable limit is as low as 39.3 nGy s -1 , and it maintains 99.5% of the luminescence intensity after 120 cycles of testing, showing extremely high stability. In addition, CCCI achieves an ultra-high spatial resolution (26.3 lp mm -1 , MTF = 0.2) in X-ray imaging, indicating its broad application prospects in the field of high-precision X-ray detection and imaging.

[0017] 4) Through the crown ether-assisted self-assembly strategy, the present invention realizes the structural optimization, luminescence performance enhancement and imaging quality improvement of organic-copper(I) halide supramolecular scintillators, providing a new feasible solution for the development of high-efficiency, low-cost and high-resolution X-ray detection materials.

[0018] 5) By using the crown ether-assisted supramolecular regulation strategy, the present invention realizes the preparation of low-dimensional, highly stable and highly ordered large-size supramolecular scintillators, and optimizes their quantum yield and radiation luminescence performance. This strategy not only promotes the development of high-efficiency X-ray imaging materials, but also provides a new technical path for the commercial application of supramolecular scintillators. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagrams of the growth of supramolecular scintillator compounds A (CNCI), B (CKCI), and C (CCCI) in Example 1.

[0020] Figure 2 Single crystal structure diagrams and crystal packing diagrams of the prepared supramolecular scintillator compounds A (CNCI), B (CKCI), and C (CCCI).

[0021] Figure 3 Optical photos and scanning electron microscope images of the prepared supramolecular scintillator compounds CNCI, CKCI, and CCCI.

[0022] Figure 4 Photoluminescence property diagrams of the prepared supramolecular scintillator compounds CNCI, CKCI, and CCCI, where A is the excitation spectrum and emission spectrum, B is the lifetime, and C is the quantum yield.

[0023] Figure 5 Radioluminescence property diagrams of the prepared supramolecular scintillator compounds CNCI, CKCI, and CCCI, where A is the radioluminescence intensity, B is the light yield, C is the detection limit, and D is the radioluminescence cycle stability.

[0024] Figure 6 Optical photo (A) and transmittance image (B) of the supramolecular scintillator compound C (CCCI) prepared in Example 12.

[0025] Figure 7 Optical photo of the supramolecular scintillator compound C after surface treatment in Example 14 and its application in X-ray imaging. Detailed implementation manners

[0026] To make the content of the present invention easier to understand, the technical solutions of the present invention are further described below in conjunction with specific implementation manners, but the present invention is not limited thereto.

[0027] Preparation of supramolecular scintillator compounds A, B, C, D, and E in Example 1 By the selective coordination of crown ethers with alkali metal ions, the structure of organic-metal halides is regulated to prepare a series of supramolecular scintillator compounds.

[0028] The specific steps are as follows: 1) Preparation of compound A (CNCI). Accurately weigh 18-crown-6, NaI, and CuI at a molar ratio of 2:1:1 respectively, place them in a ball mill and grind for 15 minutes to fully mix them evenly. The ground solid is dissolved in a mixed solvent of hypophosphorous acid and acetone with a volume ratio of 1:20, stirred until completely dissolved, and then filtered to remove insoluble impurities to obtain a clear precursor solution. The obtained precursor solution is transferred to a 20 mL glass bottle and left to stand at room temperature for 3 days. Through the solvent evaporation crystallization method, yellow transparent granular single crystals CNCI are finally precipitated at the bottom of the bottle.

[0029] 2) Preparation of Compound B (CKCI). Weigh precisely 18-crown-6, KI, and CuI respectively according to the molar ratio of 2:1:1, place them in a ball mill and grind for 15 minutes to ensure uniform mixing. Subsequently, dissolve the obtained mixture in a mixed solvent of hypophosphorous acid and acetone with a volume ratio of 1:20, stir until completely dissolved, and then filter to remove insoluble impurities to obtain a clear precursor solution. Transfer the obtained precursor solution to a 20 mL glass bottle, and use the solvent evaporation crystallization method to let it stand at room temperature for 3 days. Finally, colorless transparent rod-shaped single crystals CKCI precipitate at the bottom of the bottle.

[0030] 3) Preparation of Compound C (CCCI). Weigh precisely 18-crown-6, CsI, and CuI respectively according to the molar ratio of 2:1:1, place them in a ball mill and grind for 15 minutes to make them fully mixed. Subsequently, dissolve the ground solid in a mixed solvent of hypophosphorous acid and acetone with a volume ratio of 1:20, stir until completely dissolved, and then filter to remove insoluble impurities to obtain a clear precursor solution. Transfer the obtained precursor solution to a 20 mL glass bottle, and let it stand at room temperature for 3 days. After the solvent evaporates, finally, colorless transparent block-shaped single crystals CCCI precipitate at the bottom of the bottle.

[0031] 4) Preparation of Compound D (CLCI). Weigh precisely 18-crown-6, LiI, and CuI respectively according to the molar ratio of 2:1:1, place them in a ball mill and grind for 15 minutes to make them fully mixed. Subsequently, dissolve the ground solid in a mixed solvent of hypophosphorous acid and acetone with a volume ratio of 1:20, stir until completely dissolved, and then filter to remove insoluble impurities to obtain a clear precursor solution. Transfer the obtained precursor solution to a 20 mL glass bottle, and let it stand at room temperature for 3 days. After the solvent evaporates, finally, yellow transparent block-shaped single crystals CLCI precipitate at the bottom of the bottle.

[0032] 5) Preparation of Compound E (CRCI). Weigh precisely 18-crown-6, RbI, and CuI respectively according to the molar ratio of 2:1:1, place them in a ball mill and grind for 15 minutes to make them fully mixed. Subsequently, dissolve the ground solid in a mixed solvent of hypophosphorous acid and acetone with a volume ratio of 1:20, stir until completely dissolved, and then filter to remove insoluble impurities to obtain a clear precursor solution. Transfer the obtained precursor solution to a 20 mL glass bottle, and let it stand at room temperature for 3 days. After the solvent evaporates, finally, colorless transparent block-shaped single crystals CRCI precipitate at the bottom of the bottle.

[0033] Example 2 Based on Example 1, by regulating the halogen species (F - , Cl - , Br - ), a series of novel supramolecular scintillators are further synthesized to optimize their optical and radioluminescence properties.

[0034] The specific steps are as follows: 1) Weigh accurately 18C6, alkali metal halides (LiF, LiCl, LiBr, LiI, NaF, NaCl, NaBr, NaI, KF, KCl, KBr, KCl, RbF, RbCl, RbBr, RbI, CsF, CsCl, CsBr, CuI) and CuX (X = F - , Cl - or Br - ) according to the molar ratio of 2:1:1 respectively.

[0035] 2) Place the obtained mixture in a ball mill and grind it for 15 minutes to make it fully and evenly mixed.

[0036] 3) Put the ground solid into a mixed solvent of hypophosphorous acid and acetone with a volume ratio of 1:20, stir until it is completely dissolved, and then filter to remove insoluble impurities to obtain a clear precursor solution.

[0037] 4) Transfer the obtained precursor solution to a 20 mL glass bottle, let it stand at room temperature for 3 days, and colorless transparent or light yellow block-shaped single crystals will precipitate at the bottom of the bottle by the solvent evaporation crystallization method.

[0038] By adjusting the halogen, the obtained compounds exhibit different physical properties in terms of optical absorption, luminescence efficiency, X-ray response characteristics, etc., which helps to further optimize the application potential of supramolecular scintillator materials in the fields of X-ray detection, medical imaging, and radiation safety monitoring.

[0039] Example 3 Preparation of dibenzo-24-crown-8 supramolecular scintillator In this example, dibenzo-24-crown-8 (DB24C8) is selected as the crown ether ligand and reacts with twenty kinds of alkali metal halides (LiF, LiCl, LiBr, LiI, NaF, NaCl, NaBr, NaI, KF, KCl, KBr, KCl, RbF, RbCl, RbBr, RbI, CsF, CsCl, CsBr, CuI) and four copper(I) halides (CuF, CuCl, CuBr, CuI) respectively to prepare supramolecular scintillators.

[0040] The specific steps are as follows: 1) Weigh accurately DB24C8, alkali metal halides and copper(I) halides according to the molar ratio of 2:1:1 respectively.

[0041] 2) Place the above solid mixture in a ball mill and grind it for 15 minutes to ensure that the substances are fully and evenly mixed.

[0042] 3) The ground solid was stirred in a mixed solvent of hypophosphorous acid and acetone with a volume ratio of 1:20 until completely dissolved, and then insoluble impurities were removed by filtration to obtain a clear precursor solution.

[0043] 4) The obtained precursor solution was transferred to a 20 mL glass bottle and left standing at room temperature for 3 - 7 days. Through the solvent evaporation crystallization method, transparent single crystals were precipitated at the bottom of the bottle.

[0044] 5) Surface treatment The obtained single crystals were added to glycerol to coat their surfaces with glycerol, and then the crystal surfaces were polished step by step with sandpapers of 5000, 10000, and 15000 meshes to improve the optical transmittance and X-ray imaging performance.

[0045] Example 4 Preparation of 24-crown-8 supramolecular scintillator In this example, 24-crown-8 (24C8) was selected as the crown ether ligand and reacted with twenty kinds of alkali metal halides (LiF, LiCl, LiBr, LiI, NaF, NaCl, NaBr, NaI, KF, KCl, KBr, KCl, RbF, RbCl, RbBr, RbI, CsF, CsCl, CsBr, CuI) and four copper(I) halides (CuF, CuCl, CuBr, CuI) respectively to prepare supramolecular scintillators.

[0046] The specific steps are as follows: 1) 24C8, alkali metal halide, and copper(I) halide were accurately weighed respectively at a molar ratio of 2:1:1.

[0047] 2) The above solid mixture was placed in a ball mill and ground for 15 minutes to ensure thorough mixing.

[0048] 3) The ground solid was stirred in a mixed solvent of hypophosphorous acid and acetone with a volume ratio of 1:20 until completely dissolved, and then insoluble impurities were removed by filtration to obtain a clear precursor solution.

[0049] 4) The obtained precursor solution was transferred to a 20 mL glass bottle and left standing at room temperature for 3 - 7 days. Through the solvent evaporation crystallization method, transparent single crystals were precipitated at the bottom of the bottle.

[0050] 5) Surface treatment The obtained single crystals were added to glycerol to coat their surfaces with glycerol, and then the crystal surfaces were polished step by step with sandpapers of 5000, 10000, and 15000 meshes to improve the optical transmittance and X-ray imaging performance.

[0051] Example 5 Preparation of dibenzo-18C6 supramolecular scintillator In this example, dibenzo-18-crown-6 (DB18C6) was selected as the crown ether ligand and reacted with twenty kinds of alkali metal halides (LiF, LiCl, LiBr, LiI, NaF, NaCl, NaBr, NaI, KF, KCl, KBr, KCl, RbF, RbCl, RbBr, RbI, CsF, CsCl, CsBr, CuI) and four copper(I) halides (CuF, CuCl, CuBr, CuI) respectively to prepare supramolecular scintillators.

[0052] The specific steps are as follows: 1) Accurately weigh DB18C6, alkali metal halide, and copper(I) halide respectively according to the molar ratio of 2:1:1.

[0053] 2) Place the above solid mixture in a ball mill and grind for 15 minutes to ensure that the substances are fully and evenly mixed.

[0054] 3) Put the ground solid into a mixed solvent of hypophosphorous acid and acetone with a volume ratio of 1:20, stir until completely dissolved, and then filter to remove insoluble impurities to obtain a clear precursor solution.

[0055] 4) Transfer the obtained precursor solution to a 20 mL glass bottle and let it stand at room temperature for 3 - 7 days. Through the solvent evaporation crystallization method, transparent single crystals will precipitate at the bottom of the bottle.

[0056] 5) Surface treatment Add the obtained single crystals to glycerol to coat their surfaces with glycerol, and then polish the crystal surfaces step by step with sandpapers of 5000, 10000, and 15000 meshes respectively to improve the optical transmittance and X-ray imaging performance.

[0057] Example 6 Preparation of benzo-18-crown-6 supramolecular scintillator In this example, benzo-18-crown-6 (B18C6) was selected as the crown ether ligand and reacted with twenty kinds of alkali metal halides (LiF, LiCl, LiBr, LiI, NaF, NaCl, NaBr, NaI, KF, KCl, KBr, KCl, RbF, RbCl, RbBr, RbI, CsF, CsCl, CsBr, CuI) and four copper(I) halides (CuF, CuCl, CuBr, CuI) respectively to prepare supramolecular scintillators.

[0058] The specific steps are as follows: 1) Accurately weigh B18C6, alkali metal halide, and copper(I) halide respectively according to the molar ratio of 2:1:1.

[0059] 2) Place the above solid mixture in a ball mill and grind for 15 minutes to ensure thorough mixing of the substances.

[0060] 3) Place the ground solid in a mixed solvent of hypophosphorous acid and acetone with a volume ratio of 1:20, stir until completely dissolved, and then filter to remove insoluble impurities to obtain a clear precursor solution.

[0061] 4) Transfer the obtained precursor solution to a 20 mL glass bottle and let it stand at room temperature for 3 - 7 days. Through the solvent evaporation crystallization method, transparent single crystals will precipitate at the bottom of the bottle.

[0062] 5) Surface treatment Add the obtained single crystals to glycerol to coat their surfaces with glycerol, and then sequentially polish the crystal surfaces with sandpapers of 5000, 10000, and 15000 meshes to improve the optical transmittance and X-ray imaging performance.

[0063] Example 7 Preparation of benzo-15-crown-5 supramolecular scintillator In this example, benzo-15-crown-5 (B15C5) is selected as the crown ether ligand and reacted with twenty alkali metal halides (LiF, LiCl, LiBr, LiI, NaF, NaCl, NaBr, NaI, KF, KCl, KBr, KCl, RbF, RbCl, RbBr, RbI, CsF, CsCl, CsBr, CuI) and four copper(I) halides (CuF, CuCl, CuBr, CuI) to prepare supramolecular scintillators.

[0064] The specific steps are as follows: 1) Accurately weigh B15C5, alkali metal halide, and copper(I) halide respectively in a molar ratio of 2:1:1.

[0065] 2) Place the above solid mixture in a ball mill and grind for 15 minutes to ensure thorough mixing of the substances.

[0066] 3) Place the ground solid in a mixed solvent of hypophosphorous acid and acetone with a volume ratio of 1:20, stir until completely dissolved, and then filter to remove insoluble impurities to obtain a clear precursor solution.

[0067] 4) Transfer the obtained precursor solution to a 20 mL glass bottle and let it stand at room temperature for 3 - 7 days. Through the solvent evaporation crystallization method, transparent single crystals will precipitate at the bottom of the bottle.

[0068] 5) Surface treatment Add the obtained single crystals to glycerol to coat their surfaces with glycerol, and then sequentially polish the crystal surfaces with sandpapers of 5000, 10000, and 15000 meshes to improve the optical transmittance and X-ray imaging performance.

[0069] Example 8 Preparation of 15C5 Supramolecular Scintillator In this example, 15-crown-5 (15C5) was selected as the crown ether ligand and reacted with twenty alkali metal halides (LiF, LiCl, LiBr, LiI, NaF, NaCl, NaBr, NaI, KF, KCl, KBr, KCl, RbF, RbCl, RbBr, RbI, CsF, CsCl, CsBr, CuI) and four copper(I) halides (CuF, CuCl, CuBr, CuI) respectively to prepare the supramolecular scintillator.

[0070] The specific steps are as follows: 1) Weigh 15C5, alkali metal halide and copper(I) halide accurately according to the molar ratio of 2:1:1 respectively.

[0071] 2) Put the above solid mixture into a ball mill and grind for 15 minutes to ensure that the substances are fully and evenly mixed.

[0072] 3) Put the ground solid into a mixed solvent of hypophosphorous acid and acetone with a volume ratio of 1:20, stir until completely dissolved, and then filter to remove insoluble impurities to obtain a clear precursor solution.

[0073] 4) Transfer the obtained precursor solution to a 20 mL glass bottle and let it stand at room temperature for 3 - 7 days. Through the solvent evaporation crystallization method, transparent single crystals will precipitate at the bottom of the bottle.

[0074] 5) Surface treatment Put the obtained single crystals into glycerol to wrap their surfaces with glycerol, and then polish the crystal surfaces step by step with sandpapers of 5000, 10000, and 15000 meshes in sequence to improve the optical transmittance and X-ray imaging performance.

[0075] Example 9 Preparation of Dibenzyl 15C5 Supramolecular Scintillator In this example, dibenzyl 15C5 (DB15C5) was selected as the crown ether ligand and reacted with twenty alkali metal halides (LiF, LiCl, LiBr, LiI, NaF, NaCl, NaBr, NaI, KF, KCl, KBr, KCl, RbF, RbCl, RbBr, RbI, CsF, CsCl, CsBr, CuI) and four copper(I) halides (CuF, CuCl, CuBr, CuI) respectively to prepare the supramolecular scintillator.

[0076] The specific steps are as follows: 1) Weigh DB15C5, alkali metal halide and copper(I) halide accurately according to the molar ratio of 2:1:1 respectively.

[0077] 2) Place the above solid mixture in a ball mill and grind for 15 minutes to ensure thorough mixing of the substances.

[0078] 3) Place the ground solid in a mixed solvent of hypophosphorous acid and acetone with a volume ratio of 1:20, stir until completely dissolved, and then filter to remove insoluble impurities to obtain a clear precursor solution.

[0079] 4) Transfer the obtained precursor solution to a 20 mL glass bottle and let it stand at room temperature for 3 - 7 days. Through the solvent evaporation crystallization method, transparent single crystals will precipitate at the bottom of the bottle.

[0080] 5) Surface treatment Add the obtained single crystals to glycerol to coat their surfaces with glycerol, and then successively polish the crystal surfaces with sandpapers of 5000, 10000, and 15000 meshes to improve the optical transmittance and X-ray imaging performance.

[0081] Example 10 Preparation of benzo-12C4 supramolecular scintillator In this example, benzo-12C4 (B12C4) is selected as the crown ether ligand and reacted with twenty kinds of alkali metal halides (LiF, LiCl, LiBr, LiI, NaF, NaCl, NaBr, NaI, KF, KCl, KBr, KCl, RbF, RbCl, RbBr, RbI, CsF, CsCl, CsBr, CuI) and four copper(I) halides (CuF, CuCl, CuBr, CuI) to prepare supramolecular scintillators.

[0082] The specific steps are as follows: 1) Accurately weigh B12C4, alkali metal halide, and copper(I) halide respectively according to a molar ratio of 2:1:1.

[0083] 2) Place the above solid mixture in a ball mill and grind for 15 minutes to ensure thorough mixing of the substances.

[0084] 3) Place the ground solid in a mixed solvent of hypophosphorous acid and acetone with a volume ratio of 1:20, stir until completely dissolved, and then filter to remove insoluble impurities to obtain a clear precursor solution.

[0085] 4) Transfer the obtained precursor solution to a 20 mL glass bottle and let it stand at room temperature for 3 - 7 days. Through the solvent evaporation crystallization method, transparent single crystals will precipitate at the bottom of the bottle.

[0086] 5) Surface treatment The obtained single crystal was added to glycerol to coat its surface with glycerol, and then the surface of the crystal was polished step by step using sandpapers with mesh sizes of 5000, 10000, and 15000 to improve the optical transmittance and X-ray imaging performance.

[0087] Example 11 Preparation of 12C4 supramolecular scintillator In this example, 12-crown-4 (12C4) was selected as the crown ether ligand and reacted with twenty kinds of alkali metal halides (LiF, LiCl, LiBr, LiI, NaF, NaCl, NaBr, NaI, KF, KCl, KBr, KCl, RbF, RbCl, RbBr, RbI, CsF, CsCl, CsBr, CuI) and four copper(I) halides (CuF, CuCl, CuBr, CuI) to prepare supramolecular scintillators.

[0088] The specific steps are as follows: 1) Weigh accurately 12C4, alkali metal halide, and copper(I) halide respectively according to the molar ratio of 2:1:1.

[0089] 2) The above solid mixture was placed in a ball mill and ground for 15 minutes to ensure thorough mixing.

[0090] 3) The ground solid was placed in a mixed solvent of hypophosphorous acid and acetone with a volume ratio of 1:20, stirred until completely dissolved, and then filtered to remove insoluble impurities, obtaining a clear precursor solution.

[0091] 4) The obtained precursor solution was transferred to a 20 mL glass bottle and left to stand at room temperature for 3 - 7 days. Through the solvent evaporation crystallization method, transparent single crystals were precipitated at the bottom of the bottle.

[0092] 5) Surface treatment The obtained single crystal was added to glycerol to coat its surface with glycerol, and then the surface of the crystal was polished step by step using sandpapers with mesh sizes of 5000, 10000, and 15000 to improve the optical transmittance and X-ray imaging performance.

[0093] Example 12 Preparation of large-sized supramolecular scintillator compound C crystal.

[0094] The specific steps are as follows: 1) Weigh 18-crown-6 (0.05 mol), CsI (0.025 mol), and CuI (0.025 mol), and perform ball milling, dissolution, and filtration according to the steps of Example 1 to obtain a clear precursor solution.

[0095] 2) Transfer the obtained precursor solution to a 250 mL beaker, and in a constant temperature environment of 21 °C, slowly evaporate the solvent using the solvent evaporation crystallization method to control the crystal growth rate. After standing for 30 days, centimeter-sized, colorless and transparent bulk single crystals CCCI are successfully precipitated at the bottom of the beaker, and the crystal size is significantly improved, suitable for high-resolution X-ray detection and imaging applications.

[0096] Example 13 Preparation of Large-Size Supramolecular Scintillator Crystals In this example, a supramolecular scintillator synthesis method applicable to the entire system is extended, including different crown ethers (selected from 18-crown-6, dibenzo-24-crown-8, 24-crown-8, dibenzo-18-crown-6, benzo-18-crown-6, 15-crown-5, benzo-15-crown-5, 12-crown-4, benzo-12-crown-4), different alkali metal halides (LiF, LiCl, LiBr, NaF, NaCl, NaBr, KF, KCl, KBr, RbF, RbCl, RbBr, CsF, CsCl, CsBr), and different copper(I) halides (CuF, CuCl, CuBr). By optimizing the crystal growth conditions, the preparation of centimeter-sized large single crystals is achieved.

[0097] The specific steps are as follows: 1) Raw material weighing Accurately weigh 0.05 mol of crown ether, 0.025 mol of alkali metal halide, and 0.025 mol of copper(I) halide respectively.

[0098] 2) Ball milling and mixing Place the above solid mixture in a ball mill and grind for 15 minutes to ensure thorough mixing.

[0099] 3) Dissolution treatment Dissolve the ground solid in a mixed solvent of hypophosphorous acid and acetone with a volume ratio of 1:20, stir until completely dissolved, and then filter to remove insoluble impurities to obtain a clear precursor solution, ensuring the purity of crystal growth.

[0100] 4) Crystal growth Transfer the obtained precursor solution to a 250 mL beaker, and in a constant temperature environment of 21 °C, slowly evaporate the solvent using the solvent evaporation crystallization method to control the crystal growth rate.

[0101] 5) Standing crystallization After standing for 30 days, centimeter-sized, colorless and transparent bulk single crystals are successfully precipitated at the bottom of the beaker, and the single crystal size is significantly improved.

[0102] 6) Post-treatment The obtained large-sized single crystal is further subjected to surface treatment (such as polishing) to improve the optical transmittance and X-ray imaging quality, and is suitable for high-resolution X-ray detection and imaging applications.

[0103] Example 14 Surface treatment process of large-sized compound C single crystal and X-ray imaging application.

[0104] On the basis of Example 12, the obtained centimeter-sized CCCI single crystal is further subjected to surface treatment to optimize its optical transmittance and X-ray imaging performance.

[0105] The specific steps are as follows: The CCCI single crystal with an initial thickness of about 6 mm is added to glycerol to wrap its surface with glycerol, so as to reduce surface damage and prevent the generation of lattice defects. Subsequently, it is gradually polished with 20,000-mesh ultra-fine sandpaper to ensure that the material surface is uniform and smooth, and effectively reduce the light scattering loss. Finally, the thickness of the single crystal is precisely controlled to 0.94 mm. It shows excellent optical transmittance (transmittance > 80%) in both the visible light and X-ray ranges.

[0106] This polishing strategy significantly improves the surface quality of the single crystal, reduces light scattering, improves imaging clarity, and maintains high stability and high spatial resolution under X-ray irradiation, ensuring a clearer imaging effect in high-precision X-ray imaging applications.

[0107] Example 15 In this example, the surface treatment method for large-sized single crystals applicable to the entire system is further expanded to optimize its optical transmittance and X-ray imaging performance, and ensure stability and imaging quality in high-resolution X-ray imaging applications.

[0108] The specific steps are as follows: 1) On the basis of the large-sized single crystal prepared in Example 13, its surface is cleaned and dried to remove impurities and surface contaminants that may affect the polishing effect.

[0109] 2) The processed large-sized single crystal is wrapped with glycerol to reduce surface damage and prevent cracks or lattice defects caused by mechanical stress generated during the polishing process.

[0110] 3) The surface of the single crystal is gradually polished with 20,000-mesh ultra-fine sandpaper to ensure that the material surface is uniform and smooth, and reduce the light scattering loss. The entire polishing process needs to be carried out in a dust-free environment to avoid the influence of dust or particles on the optical quality.

[0111] 4) By precisely controlling the polishing rate, the thickness of the single crystal is finally controlled to 0.94 mm. This thickness can ensure that it has excellent optical transmittance (transmittance > 80%) in both the visible light and X-ray ranges.

[0112] The optimized single crystal exhibits high transmittance and low scattering characteristics in optical imaging and X-ray imaging, which can effectively improve the imaging contrast. Especially in X-ray imaging applications, the processed single crystal can clearly resolve fine structures and is applicable to: high-resolution medical imaging (such as mammography); industrial non-destructive testing (such as detecting internal defects of precision components); radiation safety monitoring (such as high-sensitivity X-ray detectors).

[0113] Figure 1 Schematic diagrams of the growth of supramolecular scintillator compounds A (CNCI), B (CKCI), and C (CCCI). As can be seen from the figure, under appropriate solvent conditions, by using the interaction of 18-crown-6 with alkali metal ions (Na + , K + , Cs + ), and copper-iodine coordination clusters, three supramolecular scintillators with different structures can be self-assembled by the solution method and exhibit good structural controllability and stability.

[0114] Figure 2 Single crystal structure diagrams and crystal packing diagrams of supramolecular scintillator compounds A (CNCI), B (CKCI), and C (CCCI). As can be seen from the figure, CKCI forms a one-dimensional (1D) single crown structure, while CNCI and CCCI construct zero-dimensional (0D) double crown and triple crown structures respectively. This structural difference can be attributed to the matching relationship between the alkali metal ions and the 18C6 cavity.

[0115] Figure 3 Optical photos and corresponding scanning electron microscope images of supramolecular scintillator compounds A (CNCI), B (CKCI), and C (CCCI). As shown in the figure, CNCI is a yellow crystal, and both CKCI and CCCI are colorless transparent crystals. The SEM images show that CNCI is an irregular flake, CKCI has a rod-like structure, and CCCI forms regular block-shaped single crystals, indicating its excellent crystallization quality.

[0116] Figure 4 The photoluminescence properties of compounds A, B, and C are shown. Spectral analysis shows that all three materials have good light absorption and emission characteristics. Among them, CCCI has the strongest fluorescence emission (λ = 491 nm), and its photoluminescence quantum yield is as high as 99.4%. In addition, the fluorescence lifetime curve shows that CCCI has a typical single-exponential decay, conforming to the characteristics of efficient self-trapped exciton luminescence.

[0117] Figure 5 The radioluminescence properties of compounds A, B, and C under X-ray excitation are shown. As can be seen from the figure, compound C has the highest radioluminescence yield (71000 photons MeV-1 ), and the lowest X-ray detection limit (39.3 nGy s -1 ), and its performance is far superior to that of traditional commercial scintillators NaI:Tl and CsI:Tl. At the same time, the spatial resolution of compound C in X-ray imaging reaches 26.3 lp mm -1 (MTF = 0.2), indicating its great potential in high-precision imaging applications.

[0118] Figure 6 The optical transmission performance of compound C prepared in Example 12 is shown. The optical photograph shows that it still maintains high transparency under white light and ultraviolet light irradiation, while the transmittance curve shows that the transmittance of compound C exceeds 80% in the visible light range of 400 - 800 nm, demonstrating excellent optical transmission performance, which plays an important role in improving X-ray detection sensitivity.

[0119] Figure 7 The application of polished compound C in X-ray imaging in Example 14 is further shown. The X-ray imaging experiment shows that compound C can clearly image fine structures and is successfully applied to the imaging of samples such as text, metal mesh, ruler, fish, etc., showing excellent spatial resolution and imaging contrast, proving its wide application potential in the field of high-resolution X-ray imaging.

[0120] The above are only the preferred embodiments of the present invention. All equivalent changes and modifications made according to the scope of the patent application of the present invention shall fall within the scope of the present invention.

Claims

1. A supramolecular scintillator, characterized in that, The structural general formula of the supramolecular scintillator is: (L) x @M y (S) z Cu m X n , Among them, L is selected from any one of 18-crown-6-ether, dibenzo-24-crown-8-ether, 24-crown-8-ether, dibenzo-18-crown-6-ether, benzo-18-crown-6-ether, 15-crown-5-ether, benzo-15-crown-5-ether, dibenzo-15-crown-5-ether, 12-crown-4-ether, and benzo-12-crown-4-ether; M is selected from any one of alkali metal ions Li + , Na + , K + , Rb + , Cs + ; S is derived from at least one of the absorbed water in the air or hypophosphorous acid and acetone as a solvent; X is selected from any one of halogen ions F - , Cl - , Br - , I - ; x is selected from 1, 2, or 3; y is selected from 1 or 2; z is selected from 0, 1, 2, or 3; m is selected from 1, 2, 3, 4, or 5, representing the number of Cu atoms; n = y + m, representing the total number of halogen ions coordinated with L and Cu; In this supramolecular scintillator, L forms a stable single-crown, double-crown or triple-crown coordination structure with M through supramolecular interactions to optimize the lattice stability, self-trapped exciton luminescence properties and environmental tolerance of the material.

2. The supramolecular scintillator according to claim 1, characterized in that: When L is selected from 18-crown-6 and M is selected from Na + , K + or Cs + , the supramolecular scintillator is specifically (18C6)2@Na2(H2O)3Cu4I6, (18C6)@KCuI2 or (18C6)3@Cs2Cu2I4.

3. A method for preparing a supramolecular scintillator as described in claim 1, characterized in that, It includes the following steps: 1) Weigh the crown ether compound L, alkali metal halide MX and copper halide CuX in proportion, and grind them to make them fully mixed and uniform; 2) Dissolve the ground mixture in a solvent, stir until completely dissolved, and filter to remove insoluble impurities to obtain a clear precursor solution; 3) Slowly evaporate the solvent from the obtained precursor solution at room temperature by solvent evaporation crystallization method; 4) After standing for 3 - 30 days, transparent single crystals precipitate, and large-sized supramolecular scintillators are obtained.

4. The preparation method according to claim 3, characterized in that, Step 4) also includes further surface treatment of the obtained transparent single crystals.

5. The preparation method according to claim 4, characterized in that, The surface treatment specifically involves wrapping the obtained transparent single crystals with glycerol and then gradually polishing them with 5000 - 20000 mesh ultra-fine sandpaper to reduce the thickness of the single crystals.

6. Application of a supramolecular scintillator as described in claim 1 in X-ray imaging.

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