A copper cluster scintillator with wide temperature range stability, and a preparation method and application thereof

Abstract

The application discloses a kind of wide temperature range stable copper cluster scintillator and its preparation method and application, the scintillator chemical general formula is Cu4X4 (dppyme) 2, by introducing methyl in pyridine ring 6 position structure space constraint, induce to form long-range ordered crystal packing phase, significantly enhance the lattice rigidity.This material has the microcosmic energy level structure of thermal activation delayed fluorescence (TADF) and self-trapped excitor (STE) light emitting mechanism synergism, in-190 ℃ to 150 ℃ extremely wide temperature range, excellent radiation luminescence stability is shown.The application is prepared by room temperature solution method, and process is simple.The flexible film constructed using the material improves the mechanical stability by polymer embedding process, and the spatial resolution reaches 27.8 lp / mm, which is suitable for X-ray detection and imaging in extreme environments such as deep space exploration, polar scientific research and high-temperature industrial detection.

Description

Technical Field

[0001] This application relates to the fields of optoelectronic functional materials and X-ray detection technology, and mainly to a wide-temperature-range stable copper cluster scintillator, its preparation method and application. Background Technology

[0002] X-ray scintillators, functional materials that convert high-energy rays into ultraviolet or visible light, are core components in the field of high-energy radiation detection. Their applications are extremely broad, encompassing multiple key areas such as medical imaging diagnostics, security inspection equipment, industrial non-destructive testing, and deep space exploration. As global technological competition extends to extreme environments, the operating scenarios for detectors are gradually expanding from controlled ambient-temperature laboratory environments to extreme environments such as polar scientific expeditions, deep space exploration, and high-temperature nuclear industry testing. This places extremely high demands on the stability of scintillator materials across a wide temperature range.

[0003] However, current mainstream scintillator materials face multiple bottlenecks in terms of wide-temperature adaptability. Traditional inorganic scintillators, such as thallium-doped cesium iodide (CsI:Tl) and bismuth germanate (BGO), while possessing high optical yields, exhibit fragile crystal structures at extreme temperatures: at low temperatures, inorganic crystals are prone to physical cracking due to lattice embrittlement, leading to a sharp drop in optical transmission efficiency; at high temperatures, intense lattice thermal vibrations significantly enhance nonradiative transition channels, causing excited-state energy to dissipate in the form of phonons, triggering severe "thermal quenching" phenomena; simultaneously, their rigid structure limits the realization of flexible devices. While organic scintillators possess good mechanical flexibility, their low effective atomic number limits their X-ray absorption cross-section, and their weak intermolecular interactions make them susceptible to thermal degradation and irreversible molecular structural damage at high temperatures. More importantly, the luminescence mechanisms of existing organometallic complexes or perovskite-based copper cluster scintillators are often limited to a single physical process, such as thermally activated delayed fluorescence (TADF) or self-trapped exciton luminescence (STE), lacking synergistic compensation effects among multiple mechanisms. This results in insufficient exciton utilization at extremely low temperatures due to the limited thermal activation process, and at high temperatures, the lack of strong rigid structural constraints makes it difficult to suppress exciton quenching, thus failing to achieve adaptive stability of performance over an extremely wide temperature range of -190℃ to 150℃.

[0004] In summary, developing a novel copper cluster scintillator material that possesses stable and efficient radiative-luminescent properties over a wide temperature range, can achieve multi-mechanism synergistic luminescence through specific molecular structure induction, and exhibits excellent physicochemical resistance has become a key direction for overcoming the challenges of radiation detection technology in extreme environments and meeting national strategic security needs. Summary of the Invention

[0005] To address the technical problems of poor temperature range adaptability, single luminescence mechanism, and insufficient radiation stability under extreme environments in existing scintillator materials, this application proposes a wide-temperature-range stable copper cluster scintillator, its preparation method, and its application.

[0006] According to one aspect of the present invention, a wide-temperature-range stable copper cluster scintillator is proposed, wherein the general chemical formula of the scintillator is Cu4X4(dppyme)2, wherein X is a halogen atom and dppyme is a 2-diphenylphosphine-6-methylpyridine organic ligand; in the crystal lattice of the scintillator, the methyl group at the 6-position of the pyridine ring of the dppyme forms a spatially confined structure with the adjacent molecular unit, so that the scintillator has a long-range ordered crystal stacked phase formed based on the methyl group confinement.

[0007] Preferably, the scintillator has a micro-energy level structure in which thermally activated delayed fluorescence mechanism and self-trapped exciton luminescence mechanism work together, and maintains stable radiative luminescence performance from -190℃ to 150℃.

[0008] This application achieves complementary advantages of two luminescence pathways within the same system through structural design. In the low-temperature region, the STE mechanism ensures high exciton utilization; as the temperature increases, the TADF mechanism is activated and dominates luminescence, effectively compensating for energy loss caused by thermal quenching. Thanks to this synergistic effect, the material exhibits excellent radiative luminescence stability over an extremely wide temperature range of -190℃ to 150℃, breaking through the technical bottleneck of traditional scintillators experiencing a sharp performance decline at extreme temperatures.

[0009] Preferably, the scintillator is triclinic with space group P-1. This specific low-symmetry space group reflects the extremely compact and ordered arrangement of molecules in space. This physical structure is the structural basis for achieving wide-temperature-range stability, ensuring that the material maintains phase integrity even under extreme temperature fluctuations.

[0010] Preferably, the halogen atom includes I or Br.

[0011] Preferably, the adjacent molecular unit comprises a phenyl group or a metal cluster center. In the spatially confined structure of the present invention, the methyl group at the 6-position of the pyridine ring plays a dual regulatory role: on the one hand, the methyl hydrogen atom forms a CH…π interaction with the benzene ring in the adjacent molecular unit, significantly enhancing the overall rigidity of the lattice stack through a strong intermolecular anchoring effect; on the other hand, the methyl group utilizes its specific spatial occupancy effect to construct a physical barrier between molecules, effectively isolating the metal cluster centers of adjacent molecules. This isolation effect prevents charge transfer between adjacent molecules in the excited state, thereby suppressing the self-absorption effect of light emission from the source and ensuring that the material can maintain extremely high luminescence efficiency even under high loading and aggregated states.

[0012] According to a second aspect of the present invention, a method for preparing a wide-temperature-range stable copper cluster scintillator is provided, comprising the following steps:

[0013] S1. Dissolve cuprous halide completely in acetonitrile solvent to obtain the first solution; dissolve 2-diphenylphosphine-6-methylpyridine completely in methanol solvent to obtain the second solution;

[0014] S2. At room temperature, the second solution is added dropwise to the first solution and stirred until homogeneous; the molar ratio of the cuprous halide and the 2-diphenylphosphine-6-methylpyridine is 1:1;

[0015] S3. The target product is precipitated by allowing the uniformly mixed solution to diffuse under static conditions, evaporate the solvent, or stir vigorously to obtain the crystal or powder of the copper cluster scintillator material.

[0016] This method requires no high temperature, high pressure or vacuum environment throughout the process, which greatly reduces synthesis costs and safety risks, and the product has high crystallinity and stable performance.

[0017] Preferably, the cuprous halide includes cuprous iodide or cuprous bromide.

[0018] Preferably, the specific steps of the static diffusion and solution evaporation method are as follows: the uniformly mixed solution is placed in a sealed container with a pre-reserved opening, and left to stand at room temperature for 1-2 days. The copper cluster scintillator material in the form of clustered single crystals is obtained through solution diffusion combined with solvent evaporation. The specific steps of the vigorous stirring method are as follows: the uniformly mixed solution is vigorously stirred at room temperature for 1-2 hours at a stirring rate of 500-800 rpm, and then the copper cluster scintillator material in the form of powder is obtained by filtration.

[0019] According to a third aspect of the present invention, a method for preparing a scintillator thin film is provided, comprising the following steps:

[0020] A1. A dense scintillator functional layer is formed on the substrate surface by means of filtration or deposition of wide-temperature-range stable copper cluster scintillator powder;

[0021] A2. Spin-coating a polymer solution onto the surface of the scintillator functional layer;

[0022] A3. The spin-coated film is heated and cured to obtain a flexible scintillator film.

[0023] According to a fourth aspect of the present invention, an application of a wide-temperature-range stable copper cluster scintillator in X-ray detection or imaging is proposed. Due to its excellent wide-temperature-range stability, this scintillator material can be directly applied to demanding scenarios such as deep space exploration, polar scientific expeditions, and high-temperature industrial non-destructive testing. Simultaneously, combined with the high light yield and large Stokes shift characteristics of this scintillator material, self-absorption can be effectively suppressed, achieving high-contrast, high-spatial-resolution precision imaging under low-dose radiation.

[0024] Compared with the prior art, this application has the following beneficial effects:

[0025] (1) This application precisely introduces a methyl group at the 6-position of the pyridine ring of the ligand, and utilizes the specific steric hindrance generated by it to effectively induce the formation of a long-range ordered crystalline stacking phase between molecules, which greatly enhances the lattice rigidity and thus suppresses nonradiative transitions in the excited state at the microscopic level. This structural design achieves for the first time an adaptive synergy between thermally activated delayed fluorescence (TADF) and self-trapped exciton (STE) luminescence mechanism in copper cluster materials: in the low-temperature region, the STE mechanism compensates for the loss of thermal activation efficiency, and in the high-temperature region, the TADF mechanism and the strong rigid lattice work together to resist thermal quenching, ensuring that the material has stable luminescence performance in an extremely wide temperature range of -190℃ to 150℃.

[0026] (2) This application overcomes the dependence on high temperature, high pressure or vacuum conditions in the traditional inorganic scintillator manufacturing process, and can achieve rapid synthesis of high-purity products by using a mild room temperature solution method. This preparation process is not only energy-efficient and easy to operate, but also free of harmful heavy metals such as lead and cadmium, which is in line with the development trend of green chemistry. In addition, since the copper cluster material can maintain excellent stability in both the aggregated state and high humidity environment, it effectively solves the technical defects of easy thermal degradation of organic scintillators and phase transition instability of inorganic-organic hybrid scintillators, laying a solid material foundation for large-scale industrial application.

[0027] (3) This application has made substantial progress in device fabrication by using a combination of vacuum filtration and spin coating with heat preservation curing processes to deeply embed scintillator powder into the three-dimensional network structure of the polymer. This improvement effectively solves the physical problems of powder easy detachment and scratching in traditional thin film deposition layers, and significantly enhances the mechanical stability and durability of flexible scintillator films. Relying on the self-absorption suppression effect brought about by the huge Stokes displacement of this material, the prepared flexible film exhibits excellent imaging capabilities under low-dose X-ray excitation, enabling precise detection of the internal structure of tiny biological specimens or precision industrial workpieces.

[0028] (4) The wide-temperature-range stable copper cluster scintillator provided in this application exhibits strong versatility for extreme environment applications. This material can not only meet the high sensitivity response requirements of ultra-low temperature environments such as deep space exploration and polar scientific research, but also maintain long-term stable performance under harsh conditions such as high-temperature industrial detection and nuclear power system monitoring. At the same time, the successful construction of flexible thin films also provides an ideal material solution for the development of new flexible X-ray detectors, wearable radiation monitoring equipment and portable imaging systems, which has significant social benefits and commercial value. Attached Figure Description

[0029] The accompanying drawings are included to provide a further understanding of the embodiments and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments and, together with the description, serve to explain the principles of this application. Other embodiments and many anticipated advantages of these embodiments will be readily recognized as they become better understood through reference to the following detailed description. Elements in the drawings are not necessarily to scale. The same reference numerals refer to corresponding similar parts.

[0030] Figure 1 A crystal stacked phase structure diagram of a wide-temperature-range stable copper cluster scintillator according to an embodiment of this application is shown;

[0031] Figure 2 A flowchart illustrating a method for preparing a wide-temperature-range stable copper cluster scintillator according to an embodiment of this application is shown;

[0032] Figure 3 A flowchart illustrating a method for preparing a wide-temperature-range stable copper cluster scintillator thin film according to an embodiment of this application is shown;

[0033] Figure 4 A crystal structure diagram of a wide-temperature-range stable copper-bromine cluster scintillator material according to a specific embodiment of this application is shown;

[0034] Figure 5 A crystal structure diagram of a wide-temperature-range stable copper-iodine cluster scintillator material according to a specific embodiment of this application is shown;

[0035] Figure 6 A schematic diagram illustrating the intermolecular interactions and spatial constraints of a wide-temperature-range stable copper-iodine cluster scintillator material according to a specific embodiment of this application is shown.

[0036] Figure 7 The XRD pattern of a wide-temperature-range stable copper-bromine cluster scintillator material according to a specific embodiment of this application is shown.

[0037] Figure 8 The XRD pattern of a wide-temperature-range stable copper-iodine cluster scintillator material according to a specific embodiment of this application is shown.

[0038] Figure 9 The decay lifetime curve of a wide-temperature-range stable copper-bromine cluster scintillator material according to a specific embodiment of this application is shown;

[0039] Figure 10 The decay lifetime curve of a wide-temperature-range stable copper-iodine cluster scintillator material according to a specific embodiment of this application is shown;

[0040] Figure 11 The excitation and emission spectra of a wide-temperature-range stable copper-bromine cluster scintillator material according to a specific embodiment of this application are shown;

[0041] Figure 12 The excitation and emission spectra of a wide-temperature-range stable copper-iodine cluster scintillator material according to a specific embodiment of this application are shown;

[0042] Figure 13 The photoluminescence quantum yield diagram of a wide-temperature-range stable copper-bromine cluster scintillator material according to a specific embodiment of this application is shown;

[0043] Figure 14 The photoluminescence quantum yield diagram of a wide-temperature-range stable copper-iodine cluster scintillator material according to a specific embodiment of this application is shown;

[0044] Figure 15 The radiation emission spectrum of a specific embodiment according to this application is shown;

[0045] Figure 16 The X-ray dose detection limit according to a specific embodiment of this application is shown;

[0046] Figure 17 Thermogravimetric analysis (TGA) diagram of a wide-temperature-range stable copper-bromine cluster scintillator material according to a specific embodiment of this application is shown;

[0047] Figure 18 Thermogravimetric analysis diagram of a wide-temperature-range stable copper-iodine cluster scintillator material according to a specific embodiment of this application is shown;

[0048] Figure 19 The diagram shows a radiation resistance test image of a wide-temperature-range stable copper-bromine cluster scintillator material according to a specific embodiment of this application;

[0049] Figure 20 The diagram shows a radiation resistance stability test image of a wide-temperature-range stable copper-iodine cluster scintillator material according to a specific embodiment of this application;

[0050] Figure 21 The following is a radiation emission spectrum of a wide-temperature-range stable copper-iodine cluster scintillator material according to a specific embodiment of this application in a wide-temperature-range environment;

[0051] Figure 22 The light yield of a wide-temperature-range stable copper-iodine cluster scintillator material according to a specific embodiment of this application is shown in the wide-temperature-range light yield.

[0052] Figure 23 An X-ray imaging image of a wide-temperature-range stable copper-iodine cluster scintillator film according to a specific embodiment of this application is shown;

[0053] Figure 24 The X-ray resolution calculation results of a wide-temperature-range stable copper-iodine cluster scintillator film according to a specific embodiment of this application are shown. Detailed Implementation

[0054] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings.

[0055] Where there is no conflict, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0056] A wide-temperature-range stable copper cluster scintillator with the general chemical formula Cu₄X₄(dppyme)₂, where X is a halogen atom and dppyme is a 2-diphenylphosphine-6-methylpyridine organic ligand, is described. This material utilizes the precise introduction of a methyl substituent at the 6-position of the pyridine ring, leveraging the resulting steric hindrance to construct a stable, spatially confined structure with adjacent molecular units (such as phenyl groups or metal cluster centers in adjacent ligands). This structural confinement effectively induces the formation of long-range ordered crystalline stacking phases between molecules, such as… Figure 1 As shown, this greatly enhances the lattice rigidity, thereby significantly suppressing the low-frequency vibrations and non-radiative transition energy dissipation of ligands in the excited state at the microscopic level.

[0057] Specifically, this scintillator possesses a microscopic energy level structure with a synergistic effect of thermally activated delayed fluorescence (TADF) and self-trapped exciton (STE) luminescence mechanisms. The rigid, long-range ordered stacked phase provides crucial structural support for the TADF mechanism, which dominates at high temperatures, enabling it to maintain extremely high exciton utilization through efficient antisystem crossing pathways, ensuring the material retains a very high light yield even at high temperatures. Simultaneously, in environments where low-temperature thermal energy is insufficient to trigger the TADF mechanism, this rigid lattice environment supports the STE mechanism in effectively capturing stimulated excitons and converting them into self-trapped radiative emission. Since the STE mechanism is less sensitive to temperature changes, it effectively compensates for the loss of thermal activation efficiency at low temperatures. Through the adaptive synergy of these two mechanisms, the material described in this application successfully overcomes the temperature-dependent defects of traditional scintillators, achieving excellent and stable radiative emission performance over an extremely wide temperature range of -190℃ to 150℃.

[0058] Figure 2 This is a flowchart of the preparation method for the wide-temperature-range stable copper cluster scintillator, with reference to... Figure 2 The specific steps are as follows:

[0059] S1. Dissolve cuprous halide (cuprous iodide or cuprous bromide) completely in acetonitrile to obtain the first solution; dissolve 2-diphenylphosphine-6-methylpyridine completely in methanol to obtain the second solution;

[0060] S2. At room temperature, the second solution is added dropwise to the first solution and stirred until homogeneous; the molar ratio of cuprous halide and 2-diphenylphosphine-6-methylpyridine is 1:1.

[0061] S3. The target product is precipitated by allowing the uniformly mixed solution to diffuse under static conditions, evaporate the solvent, or stir vigorously to obtain the crystal or powder of the copper cluster scintillator material.

[0062] The specific steps of the static diffusion and solution evaporation method are as follows: the uniformly mixed solution is placed in a sealed container with a pre-reserved opening, and left to stand at room temperature for 1-2 days. The clustered single crystal copper cluster scintillator material is obtained through solution diffusion combined with solvent evaporation. The specific steps of the vigorous stirring method are as follows: the uniformly mixed solution is stirred at room temperature for 1-2 hours at a stirring rate of 500-800 rpm, and then filtered to obtain the copper cluster scintillator material in powder form.

[0063] Figure 3 The flowchart illustrates the preparation method for scintillator thin films using this wide-temperature-range stable copper cluster scintillator material, with reference to... Figure 3 The specific steps are as follows:

[0064] A1. A dense scintillator functional layer is formed on the substrate surface by means of filtration or deposition of wide-temperature-range stable copper cluster scintillator powder;

[0065] A2. Spin-coat polydimethylsiloxane (PDMS) solution onto the surface of the scintillator functional layer, allowing the PDMS solution to penetrate into the gaps between the scintillator powders;

[0066] A3. The spin-coated film is heated and cured to embed the scintillator powder into the cured network structure of PDMS, thereby obtaining a flexible scintillator film.

[0067] Example 1

[0068] A wide-temperature-range stable copper-bromine cluster scintillator is prepared by the following method:

[0069] S101. In a 20 ml glass bottle, CuBr (0.72 mmol, 103 mg) was completely dissolved in 10 ml acetonitrile to prepare a CuBr acetonitrile solution; in a 10 ml glass bottle, dppyme (0.36 mmol, 100 mg) was completely dissolved in 5 ml methanol to prepare a ligand methanol solution.

[0070] S102. At room temperature, the methanol solution of the ligand is added dropwise to the CuBr acetonitrile solution and stirred until homogeneous to obtain a mixed solution.

[0071] S103. After the mixed solution is left to stand for 2 days, copper bromine cluster scintillator material single crystals are obtained by solution diffusion and volatilization. After stirring the mixed solution at room temperature for 1 hour, it is filtered and the stirring rate is 650 rpm to obtain copper bromine cluster scintillator material powder Cu4Br4(dppyme)2.

[0072] Figure 4 This is a crystal structure diagram of the copper-bromine cluster scintillator material.

[0073] Example 2

[0074] A wide-temperature-range stable copper-iodine cluster scintillator is prepared by the following method:

[0075] S201. In a 20 ml glass bottle, CuI (0.72 mmol, 138 mg) was completely dissolved in 10 ml acetonitrile to prepare a CuI acetonitrile solution; in a 10 ml glass bottle, dppyme (0.36 mmol, 100 mg) was completely dissolved in 5 ml methanol to prepare a ligand methanol solution.

[0076] S202. At room temperature, the methanol solution of the ligand is added dropwise to the CuI acetonitrile solution and stirred until homogeneous to obtain a mixed solution.

[0077] S203. After the mixed solution is left to stand for 2 days, copper-iodine cluster scintillator material single crystals are obtained by solution diffusion and volatilization. After stirring the mixed solution at room temperature for 1 hour, it is filtered and the stirring rate is 650 rpm to obtain copper-iodine cluster scintillator material powder Cu4I4(dppyme)2.

[0078] Figure 5 This is a crystal structure diagram of the copper-iodine cluster scintillator material.

[0079] Figure 6 A schematic diagram illustrating the intermolecular interactions and spatial constraints of this copper-iodine cluster scintillator is presented. In the long-range ordered crystalline stacked phase of space group P-1, due to the specific spatial orientation of the 2-diphenylphosphine-6-methylpyridine ligand, the methyl group at the 6-position of the pyridine ring acts as a crucial "anchoring-isolation" unit in the three-dimensional lattice. As shown in the diagram, the interaction between the hydrogen atom at the 6-position methyl group and the CH…π interaction formed by the benzene ring in the adjacent molecular unit exhibits an extremely short bond length, significantly shorter than the weak bonds at other positions shown in the diagram. This strong intermolecular weak bond not only locks the ligand's degrees of freedom and suppresses nonradiative transitions but also induces a highly stable rigid lattice environment. Furthermore, the 6-position methyl group utilizes its large steric hindrance effect to construct an effective physical barrier between molecules, effectively isolating the metal cluster center of adjacent molecules and forcing it to remain outside the electron cloud overlap range. This isolation effect prevents charge transfer between adjacent molecules in the excited state, thereby suppressing the luminescence self-absorption effect at its source. This spatial constraint structure, formed by the "weak bond anchoring force" provided by the adjacent benzene ring and the "spatial isolation force" provided by the adjacent metal center, is the core structural essence that enables the material to have both full-temperature stability and high luminous efficiency.

[0080] Example 3

[0081] A wide-temperature-range stable copper-iodine cluster scintillator thin film is prepared by the following method:

[0082] A101. Weigh 20 mg of the wide-temperature-range copper-iodine cluster scintillator powder obtained in Example 2, disperse it in deionized water and sonicate for 2 hours to form a uniform suspension. Use a vacuum filtration device to filter the suspension through a polyvinylidene fluoride (PVDF) microporous membrane to produce a uniform deposition layer, namely the scintillator functional layer. Furthermore, the thickness of the scintillator functional layer can be precisely controlled by adjusting the concentration of the suspension.

[0083] A102. After natural drying at room temperature, spin-coat polydimethylsiloxane (PDMS) solution onto the surface of the scintillator functional layer to allow the PDMS solution to penetrate into the gaps between the scintillator powders.

[0084] A103. After spin coating, the film is left to stand for 12 hours to allow it to initially cure at room temperature. Then, the film is placed in an oven and left to stand at 80°C for 3 hours for heat preservation and curing. Finally, it is left to stand and cool at room temperature to form a stable flexible scintillator film.

[0085] Figure 7 and Figure 8 The actual and simulated XRD spectra of Cu4Br4(dppyme)2 powder and Cu4I4(dppyme)2 powder are shown respectively. Comparative analysis revealed that the peak positions of the samples at all angles are completely consistent with the target structure, and there are no extraneous peaks. This indicates that the synthesized Cu4X4(dppyme)2 structure is consistent with the test results, and the product has high purity and contains no other impurities.

[0086] Figure 9 and Figure 10 The figures show the decay lifetime curves of Cu4X4(dppyme)2, the product prepared in Examples 1 and 2, respectively. From... Figure 9 As can be seen, the time required for the fluorescence intensity of the copper bromine cluster Cu4Br4(dppyme)2 crystal to drop to 1 / e of its maximum fluorescence intensity at excitation is 21.10 μs; from Figure 10 As can be seen, the time required for the fluorescence intensity of the copper-iodine cluster Cu4I4(dppyme)2 crystal to drop to the maximum fluorescence intensity 1 / e at excitation is 16.99 μs.

[0087] Figure 11 and Figure 12 The images show the excitation and emission spectra of Cu4X4(dppyme)2, the products prepared in Examples 1 and 2, respectively, with a test wavelength range of 250–800 nm. Figure 11 As can be seen, under the optimal excitation of a 324 nm xenon lamp, the emission spectrum of Cu4Br4(dppyme)2 ranges from 500 to 800 nm, with the optimal emission peak at 629 nm, exhibiting orange-red luminescence; from Figure 12 As can be seen, under the optimal excitation of a 304 nm xenon lamp light source, the emission spectrum of Cu4I4(dppyme)2 ranges from 500 to 800 nm, with the optimal emission peak located at 617 nm, exhibiting an orange-yellow emission.

[0088] Figure 13 and Figure 14 The images show the photoluminescence quantum yields of Cu4X4(dppyme)2 prepared in Examples 1 and 2, respectively. The test results show that the room temperature photoluminescence quantum yield of Cu4Br4(dppyme)2 is 87.53%, and that of Cu4I4(dppyme)2 is 98.77%.

[0089] Figure 15 The figures show the radiative emission spectra of the Cu4X4(dppyme)2 scintillator products prepared in Examples 1 and 2. Under the same test conditions, using X-rays as the excitation source, the X-ray radiative emission spectra of the same volume of standard reference commercial scintillators LYSO:Ce, BGO, and Cu4X4(dppyme)2 scintillator materials were measured. The figures show that the standard light yields of LYSO:Ce and BGO are 25000 photons / MeV and 8000 photons / MeV, respectively. Through integration and calculation using formulas, the light yield of Cu4Br4(dppyme)2 is 54725 photons / MeV, and that of Cu4I4(dppyme)2 is 55545 photons / MeV. This indicates that the light yield of the Cu4X4(dppyme)2 scintillator material prepared in this application far exceeds that of commercial scintillators.

[0090] Figure 16 The X-ray dose detection limits of Cu4X4(dppyme)2, the product prepared in Examples 1 and 2, are shown. Under the same test conditions, using X-rays as the excitation source, the X-ray radioluminescence spectra of the same volume of the standard reference commercial scintillator BGO and Cu4X4(dppyme)2 scintillator material were measured at different radiation doses with the same radiation gradient. The lowest detection limit of each scintillator was calculated by the slope of the radiation intensity peak at each dose with respect to the radiation dose. The tests showed that the lowest detection limit of Cu4Br4(dppyme)2 was 294 nGy / s, the lowest detection limit of Cu4I4(dppyme)2 was 210 nGy / s, and the lowest detection limit of BGO was 1.12 μGy / s. This indicates that the lowest detection limit of the Cu4X4(dppyme)2 scintillator material prepared in this application is one order of magnitude lower than that of commercial scintillators.

[0091] Figure 17 and Figure 18 Thermogravimetric analysis (TGA) curves of Cu4X4(dppyme)2, the products prepared in Examples 1 and 2, are shown. The temperature was increased from room temperature to 800℃ at a rate of 10℃ / min under a nitrogen atmosphere, and thermal stability data were obtained by real-time monitoring of sample mass changes. The results show that the 5% thermogravimetric temperature (TGT) of Cu4Br4(dppyme)2 is 298℃, with the main decomposition temperature range being 320-420℃; the 5% TGT of Cu4I4(dppyme)2 is 325℃, with the main decomposition stage occurring in the 350-450℃ range. This indicates that the wide-temperature-range stable copper cluster scintillator material prepared in this application possesses excellent thermal stability.

[0092] Figure 19 and Figure 20The figures show the radiation stability test results of Cu4X4(dppyme)2, the prepared products of Examples 1 and 2, respectively. The emission photostability test of Cu4X4(dppyme)2 under an X-ray dose of 1.25 mGy / s for 60 repeated switching cycles revealed that the emission intensity of both Cu4Br4(dppyme)2 and Cu4I4(dppyme)2 remained almost unchanged under X-rays. This indicates that the wide-temperature-range stable copper cluster scintillator material prepared in this application has high radiation resistance.

[0093] The Cu4I4(dppyme)2 prepared in Example 2 was characterized and tested for radioluminescence in the range from low temperature to high temperature. The test results are as follows: Figure 21 and Figure 22 As shown. Figure 21 The image shows the radiative emission spectrum of Cu₄I₄(dppyme)₂ over a wide temperature range. This test used X-rays as the excitation source and commercial scintillators LYSO:Ce and BGO as standard references, while maintaining other test conditions identical. Through analysis of… Figure 21 By integrating the radiative luminescence intensity and combining it with the corresponding formula, the light yield of Cu₄I₄(dppyme)₂ over a wide temperature range can be obtained, as shown in the figure. Figure 22 As shown, the light yield of Cu4I4(dppyme)2 is 55358 photons / MeV at -190℃, 56377 photons / MeV at -50℃, 55545 photons / MeV at 30℃, 49224 photons / MeV at 90℃, and 41338 photons / MeV at 150℃, while the standard light yields of commercial scintillators LYSO:Ce and BGO are 25000 photons / MeV and 8000 photons / MeV, respectively. This indicates that even at extreme temperatures, the light yield of the Cu4I4(dppyme)2 scintillator material prepared in this application still far exceeds that of commercial scintillators.

[0094] An X-ray imaging platform system was constructed to characterize the wide-temperature-range stable copper-iodine cluster scintillator thin film prepared in Example 3 using X-ray imaging applications. The system consisted of a commercial MAGPRO X-ray tube operating at 70 kV as the X-ray source, a Sony ILCE-7M4 as the charge-coupled device camera, and a NOVA2S-EX multi-fiber spectrometer. The target material of the MAGPRO X-ray tube was a tungsten target, with a maximum tube voltage of 70 kV, a maximum tube current of 100 μA, and a maximum power output of 7 W. The X-ray source was 5 cm away from the scintillator thin film.

[0095] Figure 23This is an X-ray imaging image of the wide-temperature-range stable copper-iodine cluster scintillator thin film prepared in Example 3. Using this scintillator thin film as a substrate, the actual object was placed above the film, and X-rays were sequentially transmitted through the line pairs (...). Figure 23 a) Dried small fish ( Figure 23 b) with the specimen of the Chinese pond turtle ( Figure 23 c) The X-rays are irradiated onto the surface of the scintillator film. After being absorbed by the film deposition layer, the X-rays are excited to emit orange visible light, which is then reflected by a prism and captured by a camera. Finally, images of the line pair card, dried small fish, and turtle specimens are obtained, showing clear internal structures of the objects. The image of the line pair card shows that the resolution of the film is at least 20 lp / mm.

[0096] Figure 24 The X-ray resolution calculation results for this scintillator film are shown below. During the resolution test, a thin tungsten sheet (0.5 mm thick) with sharp edges was placed on the surface of the scintillator film, tilted at approximately 10–20°. An image of the tilted edge was then acquired using an X-ray imaging system. The modulation transfer function was calculated using the tilted edge method with ImageJ software, resulting in a spatial resolution of 27.8 lp / mm for the scintillator film.

[0097] In summary, this invention presents a wide-temperature-range stable copper cluster scintillator. Through precise molecular structure modification and spatial constraint design, it successfully overcomes the technical challenges of unstable luminescence performance and susceptibility to thermal quenching in traditional scintillator materials under extreme temperature environments. Experimental results show that this material not only maintains high light yield and high structural stability across the entire temperature range of -190℃ to 150℃, but its flexible thin films can also achieve high spatial resolution precision imaging under complex environments. This invention not only achieves a green and efficient breakthrough in synthesis processes, but also demonstrates enormous application potential and commercial value in strategic emerging fields such as deep space exploration, polar research, and stringent industrial non-destructive testing, providing key material support and technical solutions for developing next-generation high-performance, environmentally adaptive radiation detection equipment.

[0098] The specific embodiments of this application have been described above, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

Claims

1. A wide-temperature-range stable copper cluster scintillator, characterized in that, The scintillator has the general chemical formula Cu4X4(dppyme)2, where X is a halogen atom and dppyme is a 2-diphenylphosphine-6-methylpyridine organic ligand. In the crystal lattice of the scintillator, the methyl group at the 6-position of the pyridine ring of the dppyme forms a dual spatially confined structure with adjacent molecular units, including weak CH…π bond interactions and steric hindrance isolation, giving the scintillator a long-range ordered crystal stacking phase based on the methyl group confinement. The steric hindrance effect of the methyl group isolates the metal cluster centers of adjacent molecules outside the electron cloud overlap range. The scintillator has a microscopic energy level structure with the synergistic effect of thermally activated delayed fluorescence and self-trapped exciton luminescence mechanisms, maintaining stable radiative emission performance from -190℃ to 150℃.

2. The wide-temperature-range stable copper cluster scintillator according to claim 1, characterized in that, The scintillator is a triclinic crystal system with space group P-1.

3. The wide-temperature-range stable copper cluster scintillator according to claim 1, characterized in that, The halogen atom includes I or Br.

4. The wide-temperature-range stable copper cluster scintillator according to claim 1, characterized in that, The adjacent molecular units include phenyl or metal cluster centers.

5. A method for preparing a wide-temperature-range stable copper cluster scintillator as described in any one of claims 1-4, characterized in that, Includes the following steps: S1. Dissolve cuprous halide completely in acetonitrile solvent to obtain the first solution; dissolve 2-diphenylphosphine-6-methylpyridine completely in methanol solvent to obtain the second solution; S2. At room temperature, the second solution is added dropwise to the first solution and stirred until homogeneous; the molar ratio of the cuprous halide and the 2-diphenylphosphine-6-methylpyridine is 1:1; S3. The target product is precipitated by allowing the uniformly mixed solution to diffuse under static conditions, evaporate the solvent, or stir vigorously to obtain the crystal or powder of the copper cluster scintillator material.

6. The method for preparing a wide-temperature-range stable copper cluster scintillator according to claim 5, characterized in that, The cuprous halide includes cuprous iodide or cuprous bromide.

7. The method for preparing a wide-temperature-range stable copper cluster scintillator according to claim 5, characterized in that, The specific steps of the static diffusion and solution evaporation method are as follows: the uniformly mixed solution is placed in a sealed container with a pre-reserved opening, and left to stand at room temperature for 1-2 days. The copper cluster scintillator material in the form of clustered single crystals is obtained through solution diffusion combined with solvent evaporation. The specific steps of the vigorous stirring method are as follows: the uniformly mixed solution is stirred at room temperature for 1-2 hours at a stirring rate of 500-800 rpm, and then the copper cluster scintillator material in the form of powder is obtained by filtration.

8. A method for preparing a scintillator thin film, characterized in that, The fabrication process using a wide-temperature-range stable copper cluster scintillator as described in any one of claims 1-4 includes the following steps: A1. A dense scintillator functional layer is formed on the substrate surface by means of filtration or deposition of the wide temperature range stable copper cluster scintillator powder as described in any one of claims 1-4; A2. Spin-coating a polymer solution onto the surface of the scintillator functional layer; A3. The spin-coated film is heated and cured to obtain a flexible scintillator film.

9. The application of a wide-temperature-range stable copper cluster scintillator as described in any one of claims 1-4 in X-ray detection or imaging for non-disease diagnosis and treatment purposes.

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