Coordination polymer scintillator, flexible scintillator film and application thereof

Abstract

The invention relates to the technical field of photoluminescence materials, and particularly discloses a coordination polymer scintillator, a flexible scintillator film and application thereof.The prepared coordination polymer scintillator emits green light under a 360-nm excitation light source and under irradiation of an X-ray light source, has excellent linear responsiveness to X-rays and can be applied to the field of photoluminescence materials. According to the present invention, the prepared scintillator film has the obvious thermal activation enhanced luminescence, when the signal-to-noise ratio is 3, the lowest detection limit of the scintillator can achieve 29.6 nGy / s, the value is about 186 times lower than the detection limit (5500 nGy / s) required by a typical medical imaging system, and the prepared scintillator film can achieve the X-ray imaging effect on different objects, such that the X-ray imaging effect can be easily achieved. The scintillator film prepared by the invention can completely replace the current commercial scintillator.

Description

Technical Field

[0001] The present invention relates to the technical field of photoluminescent materials, and particularly relates to a coordination polymer scintillator, a flexible scintillator film and their applications. Background Art

[0002] X-rays are electromagnetic waves with extremely short wavelengths and high energies, having strong penetration ability. X-ray detection is widely used in fields such as computed tomography (CT) examination, non-destructive testing, material research, radiation monitoring, and astronomical exploration. In recent years, X-ray indirect detection has advantages over direct detection in terms of cost and stability, and has become a research hotspot in emerging fields.

[0003] As the core functional material for radiation-photon energy conversion, the performance of scintillators directly determines the application efficiency in fields such as X-ray imaging, radiation detection, and photodynamic therapy. The synthesis processes of existing inorganic scintillators generally rely on high-temperature solid-state reactions and chemical vapor deposition techniques. These processes not only have complex preparation procedures and high energy consumption, but also easily produce heavy metal-containing waste liquids during the purification process of rare earth elements, posing environmental safety risks. Taking thallium-based scintillators as an example, their synthesis process requires long-term high-temperature annealing treatment, resulting in an overly long single crystal growth cycle and significantly increasing the manufacturing cost. In addition, heavy metal components may cause radioactive isotope accumulation problems under long-term irradiation, further limiting their applications in sensitive fields such as biomedicine. In contrast, all-organic scintillators have attracted attention due to their solution processing characteristics and environmental friendliness advantages. However, research shows that as the temperature increases, the vibration modes of chemical bonds within organic molecules will change significantly, leading to rapid energy dissipation of excitons through non-radiative transition paths. The X-ray luminescence intensity of typical organic scintillators shows a sharp decay at high temperatures, and the thermal cycle stability is difficult to meet the long-term use requirements of industrial equipment.

[0004] The current technical system shows obvious limitations: there are irreconcilable contradictions among the thermal stability, preparation cost, and environmental toxicity of inorganic scintillators, while organic scintillators are restricted by the dual constraints of exciton localization ability and temperature tolerance. This performance gap of materials seriously hinders the expanded application of scintillator technology in emerging scenarios such as high-temperature radiation detection and wearable dose monitoring. Therefore, it is necessary to develop a new type of X-ray scintillator to meet the actual application requirements. Summary of the Invention

[0005] Aiming at the deficiencies of the existing technology, the purpose of the present invention is to provide a coordination polymer scintillator, a flexible scintillator film and their applications.

[0006] To achieve the above purpose, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a coordination polymer scintillator, which is prepared by using a metal halide cluster, an organic phosphine ligand, and a diazine ligand.

[0008] Preferably, the metal element of the metal halide cluster is selected from copper, silver, or tin.

[0009] Preferably, the halogen element of the metal halide cluster is selected from chlorine, bromine, or iodine.

[0010] Preferably, the organic phosphine ligand is selected from triphenylphosphine and / or triphenylphosphine derivatives.

[0011] Preferably, the diazine ligand is selected from bipyridine, pyrazine, or piperazine.

[0012] Preferably, the molar ratio of the metal halide cluster, the organic phosphine ligand, and the diazine ligand is 0.5 - 1:1 - 2:0.5 - 1.

[0013] In a second aspect, the present invention provides a flexible scintillator film. The preparation method of the flexible scintillator film includes: dispersing the above-mentioned coordination polymer scintillator in a polymer matrix material to obtain the flexible scintillator film.

[0014] Preferably, the mass ratio of the coordination polymer to the polymer matrix material is 5 - 10:5 - 10.

[0015] Preferably, the polymer matrix material is selected from polydimethylsiloxane, polymethyl methacrylate, polyvinyl alcohol, polycarbonate, or polystyrene.

[0016] In a third aspect, the present invention also provides the application of the above-mentioned flexible scintillator film in X-ray imaging and detection.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The coordination polymer scintillator prepared by the present invention emits yellow light under both a 360 nm excitation light source and X-ray source irradiation, exhibits excellent linear responsiveness to X-rays, and shows obvious thermally activated enhanced luminescence. When the signal-to-noise ratio is 3, the minimum detection limit of this scintillator reaches 29.6 nGy / s, which is approximately 186 times lower than the detection limit (5500 nGy / s) required by typical medical imaging systems. At the same time, the scintillator film prepared by the present invention can achieve X-ray imaging effects for different objects, with a spatial resolution of up to 23 lp / mm at room temperature and up to 35 lp / mm at 430 K; compared with existing scintillator materials, the resolution of the flexible scintillator film prepared by the present invention does not decrease but increases at high temperatures, having good application prospects; the scintillator film prepared by the present invention can completely replace currently commercially available scintillators. Brief Description of the Drawings

[0019] Figure 1 Structural formula of the copper-iodine coordination polymer scintillator prepared in Example 1;

[0020] Figure 2 Emission spectrum of the copper-iodine coordination polymer scintillator prepared in Example 1;

[0021] Figure 3 Characterization diagram of the X-ray detection performance of the copper-iodine coordination polymer scintillator prepared in Example 1;

[0022] Figure 4 Characterization diagram of the X-ray imaging system of the flexible scintillator film prepared in Example 2;

[0023] Figure 5 Resolution test result diagram of the flexible scintillator film prepared in Example 2;

[0024] Figure 6 Structural formula of the copper-iodine coordination polymer scintillator prepared in Example 3. Detailed Description of the Invention

[0025] The present invention will be further described in detail below through specific preferred embodiments, but the present invention is not limited to the following embodiments.

[0026] It should be noted that, unless otherwise specified, the chemical reagents involved in the present invention are all purchased through commercial channels.

[0027] The present invention provides a coordination polymer scintillator, which is prepared by using metal halides, organic phosphine ligands and diazine ligands.

[0028] More specifically, the preparation method of the coordination polymer scintillator is as follows:

[0029] Dissolve the metal halide cluster in a solvent, add the organic phosphine ligand under stirring, mix evenly, then continue to add the diazine ligand thereto, heat and stir for reaction. After the reaction is completed, filter, wash and dry to obtain the coordination polymer scintillator.

[0030] In the technical solution disclosed in the present invention, the metal element of the metal halide cluster is selected from copper, silver or tin, but is not limited to the several listed above, and others not listed are also applicable.

[0031] In the technical solution disclosed in the present invention, the halogen element of the metal halide cluster is selected from chlorine, bromine or iodine.

[0032] In the technical solution disclosed by the present invention, the metal halide clusters may be selected from cuprous chloride, cuprous bromide, cuprous iodide, stannous chloride, stannous bromide, stannous iodide, silver bromide or silver iodide, for example.

[0033] In the technical solution disclosed by the present invention, the organic phosphine ligand is selected from triphenylphosphine and / or triphenylphosphine derivatives.

[0034] In the technical solution disclosed by the present invention, the dinitrogen ligand is selected from bipyridine, pyrazine or piperazine, but is not limited to the several listed above, and others not listed are equally applicable.

[0035] In the technical solution disclosed by the present invention, the molar ratio of the metal halide clusters, the organic phosphine ligand and the dinitrogen ligand is 0.5 - 1:1 - 2:0.5 - 1. For example, it may be selected from 0.5:1:0.5, 0.5:1:1, 0.5:2:0.5, 0.5:2:1, but is not limited to the listed values, and other values not listed within the numerical range are equally applicable.

[0036] In the technical solution disclosed by the present invention, the temperature of the heating and stirring reaction is 25 - 75 °C. For example, it may be selected from 25 °C, 30 °C, 35 °C, 40 °C, 45 °C, 50 °C, 55 °C, 60 °C, 65 °C, 70 °C, 75 °C; the time of the heating and stirring reaction is 72h - 240h. For example, it may be selected from 72h, 96h, 120h, 144h, 168h, 240h, but is not limited to the listed values, and other values not listed within the numerical range are equally applicable.

[0037] The present invention provides a flexible scintillator film, and the preparation method of the flexible scintillator film is as follows:

[0038] Disperse the coordination polymer scintillator in the polymer matrix material, and the flexible scintillator film is obtained.

[0039] More specifically, the preparation method of the flexible scintillator film includes:

[0040] Add the coordination polymer and the polymer matrix material into an organic solvent, stir evenly, then perform ultrasonic treatment, add a dispersant, and continue ultrasonic dispersion to be evenly dispersed to obtain a turbid liquid;

[0041] Pour the turbid liquid into a mold, and volatilize the solvent at room temperature to obtain the flexible scintillator film.

[0042] In the technical solution disclosed in the present invention, the mass ratio of the coordination polymer to the polymer matrix material is 5-10:5-10. For example, 5:5, 5:6, 5:7, 5:8, 5:9, 5:10, 8:5, 8:6, 8:8, 10:5, 10:6, 10:8, 10:10 can be selected, but it is not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0043] In the technical solution disclosed in the present invention, the polymer matrix material is selected from polymer materials with high light transmittance, excellent chemical stability and good mechanical properties, including but not limited to polydimethylsiloxane (PDMS), polymethyl methacrylate (PMMA), polyvinyl alcohol (PVA), polycarbonate (PC) or polystyrene (PS).

[0044] In the technical solution disclosed in the present invention, the dispersant is selected from dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, dimethylacetamide, absolute ethanol or toluene.

[0045] The present invention also provides the application of the above flexible scintillator film in X-ray imaging and detection.

[0046] In the application disclosed in the present invention, for example, the obtained flexible scintillator film can be arranged at the light signal receiving end of the image acquisition component; the image acquisition component includes but is not limited to a digital camera and a photoelectric detection device, and among them, the photoelectric detection device is preferably any one of a photomultiplier tube (PMT) detector, a thin film transistor (TFT) photodiode sensor, a charge coupled (CCD) sensor, a complementary metal oxide semiconductor (CMOS) sensor or an indium gallium zinc oxide (IGZO) TFT sensor.

[0047] The present invention will be further described below through more specific embodiments. It should be noted that this illustrative example is only a specific embodiment of the present invention and does not limit the protection scope of the present invention.

[0048] Example 1

[0049] A preparation method of a copper iodide coordination polymer scintillator includes the following steps:

[0050] Copper(I) iodide (95.2 mg, 0.5 mmol) was dissolved in 10 mL of anhydrous acetonitrile, and triphenylphosphine (262.29 mg, 1.0 mmol) was slowly added under magnetic stirring. After stirring for half an hour, 4,4'-bipyridine (78.1 mg, 0.5 mmol) was added continuously. The resulting mixture was heated to 70 °C and stirred for 168 h. The formation of a yellow product could be observed in the flask. The reaction solution was filtered and washed twice with ethanol and water respectively. The obtained product was first dispersed in ethanol by ultrasound, and then the resulting mixture was placed in a vacuum drying oven. The vacuum drying oven was evacuated and replaced with nitrogen three times. Then the drying oven was heated to 200 °C and kept at this temperature for 90 min. Finally, it was cooled in the furnace under a nitrogen atmosphere to obtain the copper-iodine coordination polymer scintillator.

[0051] Among them, the chemical general formula of the copper-iodine coordination polymer scintillator is: [{Cu2I2(PPh3)2}(4,4’-bpy)] n 。

[0052] The structural formula of the copper-iodine coordination polymer scintillator prepared in this example is as Figure 1 shown.

[0053] The emission spectrum of the copper-iodine coordination polymer scintillator prepared in this example is as Figure 2 shown, Figure 2 where a is the photoluminescence spectrum of the copper-iodine coordination polymer scintillator under irradiation with a xenon lamp at a wavelength of 360 nm. The inset is a photograph of the yellow luminescence of this sample under ultraviolet lamp irradiation; Figure 2 where b is the luminescence lifetime of the copper-iodine coordination polymer scintillator, indicating that the copper-iodine coordination polymer scintillator has a luminescence lifetime at the μs level; Figure 2 where c is the photoluminescence spectrum of the copper-iodine coordination polymer at variable temperatures, and it can be seen that the luminescence performance of the copper-iodine coordination polymer scintillator shows obvious thermally activated enhancement; Figure 2 where d shows the excitation-photoluminescence spectrum of the copper-iodine coordination polymer scintillator; these data indicate that the copper-iodine coordination polymer scintillator has both short lifetime and thermally activated enhanced luminescence characteristics.

[0054] The X-ray detection performance characterization diagram of the copper-iodine coordination polymer scintillator prepared in this example is as Figure 3 shown.

[0055] Figure 3 where a is the radioluminescence spectrum of the copper-iodine coordination polymer scintillator under X-ray irradiation with a dose rate of 278 mGy / s at a voltage of 50 kV. The inset is an X-ray scintillation photograph of this sample.

[0056] Figure 3Figure b is a linear graph of the radioluminescence intensity of the copper-iodine coordination polymer scintillator versus the dose rate; the detection limit performance of the scintillator was determined by exposing it to X-ray photons in a dose rate range (0.688 to 278 mGy / s), which was controlled by adjusting the current and voltage of the X-ray source. By quantitatively analyzing the correlation between the luminescence intensity and the X-ray dose rate, from Figure 3 Figure b, it can be seen that there is a good linear response relationship between the two, indicating that the material has excellent dose measurement accuracy and stability; it is particularly noteworthy that when the signal-to-noise ratio is 3, the lowest detection limit of this scintillator reaches 29.6 nGy / s, which is about 186 times lower than the detection limit (5500 nGy / s) required by typical medical imaging systems.

[0057] Figure 3 Figure c is a graph of the radioluminescence intensity of the scintillator under continuous irradiation and repeated excitation cycles; in addition to the detection limit, radiation tolerance stability is another important evaluation parameter for the performance of the scintillator. As Figure 3 shown in Figure c, after the scintillator undergoes 100 on-off cycles at a dose rate of 278 mGy / s, the luminescence intensity of the material remains basically unchanged, indicating its high stability.

[0058] It can be seen that the copper-iodine coordination polymer scintillator prepared by the present invention has both high sensitivity and high stability in response to X-ray photons.

[0059] Example 2

[0060] A method for preparing a flexible scintillator film, comprising the following steps:

[0061] Weigh 50 mg of polymethyl methacrylate (PMMA) and 60 mg of the copper-iodine coordination polymer scintillator prepared in Example 1 into a sample bottle containing a magnetic stirrer, add 0.6 ml of chlorobenzene, and quickly stir at 90 °C until all the samples are dissolved. Immediately pour the solution into the sample bottle, place it in a high-speed ultrasonic crushing instrument and run for 25 min, then add 0.8 ml of ethanol, and continue ultrasonic crushing to obtain a turbid liquid.

[0062] Fix the flexible mold (a round groove with a diameter of 3.5 cm) to the glass substrate, and then quickly pour the turbid liquid into the flexible mold, and place it at room temperature to volatilize the solvent, thus obtaining the flexible scintillator film.

[0063] The characterization diagram of the X-ray imaging system of the flexible scintillator film prepared in this example is as Figure 4 shown. This imaging system mainly consists of the following key components: an X-ray source, a sample to be measured, a flexible scintillator film, and a high-performance digital camera. Among them Figure 4Figure a shows the bright field and X-ray scintillation photograph of the flexible scintillator film. It can be seen that the flexible scintillator film exhibits bright yellow luminescence under X-ray excitation; Figure 4 Figure b is the radiation spectrum of the flexible scintillator film; Figure 4 Figure c shows the X-ray imaging photographs of the electronic chip at different ambient temperatures. As the chip is heated from 310K to 470K, the cross pattern inside the chip can be observed to gradually become clear at high temperatures, indicating the excellent radiation performance of the flexible scintillator film at high temperatures.

[0064] Resolution test: An X-ray imaging platform was set up. The system consisted of a Mini-X2 X-ray tube (Amptek Inc) as the excitation source, an Edinburgh FS5 spectrometer, and a camera (Canon EOS R5). Among them, the target material of the Mini-X2 X-ray tube was Au, P max = 10W, V max = 60kV, I max = 150μA. Specifically, during the test, the X-ray source emitted a current of 150μA and a voltage of 60kV. The lead sheet edge imaging technology was adopted, and the modulation transfer function (MTF) fitting analysis was combined. The results are as Figure 5 shown. When the MTF value is 0.2, the spatial resolution of the flexible scintillator film prepared in Example 2 can reach 23 lp / mm at room temperature and 35 lp / mm at 430K; compared with the existing scintillator materials, the flexible scintillator film prepared in the present invention has an increasing resolution at high temperatures instead of a decreasing one, showing good application prospects.

[0065] Example 3

[0066] A preparation method of a copper-iodine coordination polymer scintillator, comprising the following steps:

[0067] Dissolve cuprous iodide (95.2 mg, 0.5 mmol) in 15 mL of anhydrous acetonitrile, and slowly add tris(3-methoxyphenyl)phosphine (252.36 mg, 1.0 mmol) under magnetic stirring. After stirring for half an hour, continue to add 4,4'-bipyridine (78.1 mg, 0.5 mmol). Heat the obtained mixture to 50°C and keep stirring and reacting for 128 h. It can be observed that a yellow product is formed in the bottle. Filter the reaction solution and wash it twice with ethanol and water respectively. First, disperse the obtained product into ethanol by ultrasonic treatment, then put the obtained mixture into a vacuum drying oven, perform three times of evacuation and gas replacement on the vacuum drying oven, then heat the drying oven to 200°C and keep it warm for 90 min, and finally cool it down with the furnace under a nitrogen atmosphere to obtain the copper-iodine coordination polymer scintillator.

[0068] The general chemical formula of the prepared scintillator is: [{Cu2I2(PPh3C3H9O3)2}(4,4-bpy)] n .

[0069] The structural formula of the copper iodide coordination polymer scintillator prepared in this example is as Figure 6 shown.

[0070] Finally, it should be noted that the above embodiments do not limit the present invention in any form. For those skilled in the art, based on the present invention, some modifications and improvements can be made. Therefore, any modification or improvement made without departing from the spirit of the present invention falls within the scope of protection required by the present invention.

Claims

1. A coordination polymer scintillator, characterized in that, The coordination polymer scintillator is prepared by using a metal halide cluster, an organophosphine ligand, and a diazine ligand.

2. The coordination polymer scintillator according to claim 1, wherein The metal element of the metal halide cluster is selected from copper, silver, or tin.

3. The coordination polymer scintillator according to claim 1, wherein The halogen element of the metal halide cluster is selected from chlorine, bromine, or iodine.

4. The coordination polymer scintillator according to claim 1, wherein The organophosphine ligand is selected from triphenylphosphine and / or triphenylphosphine derivatives.

5. The coordination polymer scintillator according to claim 1, wherein The diazine ligand is selected from bipyridine, pyrazine, or piperazine.

6. The coordination polymer scintillator according to claim 1, wherein The molar ratio of the metal halide cluster, the organophosphine ligand, and the diazine ligand is 0.5 - 1:1 - 2:0.5 - 1.

7. A flexible scintillator film, characterized in that, The preparation method of the flexible scintillator film includes: dispersing the coordination polymer scintillator according to any one of claims 1 - 6 in a polymer matrix material, thereby obtaining the flexible scintillator film.

8. The flexible scintillator thin film according to claim 7, characterized in that, The mass ratio of the coordination polymer scintillator to the polymer matrix material is 5 - 10:5 - 10.

9. The flexible scintillator thin film according to claim 7, wherein The polymer matrix material is selected from polydimethylsiloxane, polymethyl methacrylate, polyvinyl alcohol, polycarbonate, or polystyrene.

10. Use of the flexible scintillator film according to any one of claims 7 - 9 in X - ray imaging and detection.

Images