Preparation and application method of copper-iodine cluster-based micro-cubic scintillator and film

Abstract

The present invention relates to a method for preparing and applying copper-iodine cluster-based microcube scintillator and thin film, which is a microcube scintillator capable of generating ionizing radiation excitation emission. The microcube scintillator comprises a copper-iodine cluster-based microcube scintillator doped in a substrate layer. The chemical formula of the copper-iodine cluster-based microcube scintillator is C 18 H 38 Cu4I6N4. The substrate layer is a polymer with high light transmittance, excellent chemical stability and good mechanical properties. Another aspect of the present invention is an ionizing radiation imaging system, in which the microcube scintillator is placed behind the digital camera of the substrate layer doped with the microcube scintillator. The photodetector can be any of the following. Typically, the photodetector is a photomultiplier tube (PMT) detector, a thin film transistor (TFT) photodiode sensor, a charge-coupled device (CCD) sensor, a complementary metal-oxide-semiconductor (CMOS) sensor or an indium gallium zinc oxide (IGZO) TFT sensor.

Description

Technical Field

[0001] This invention pertains to microcubic scintillators, specifically a copper-iodine cluster-based microcubic scintillator and its thin film preparation and application method. Background Technology

[0002] Scintillators are materials that emit low-energy ultraviolet and visible photons in response to ionizing radiation (such as X-rays or gamma rays). This property makes scintillators widely used in non-destructive testing, X-ray astronomy, security inspection, and medical radiography. See Martin S., Nucl. Instrum. Methods in Phys., 2013, 731, 57-63.

[0003] X-ray scintillators typically incorporate heavy elements such as Bi, Pb, and Lu to enhance their X-ray absorption efficiency, thereby increasing the number of excitons generated and potentially leading to superior radiative emission performance. Traditional scintillators, usually in the form of heavy metal-containing inorganic phosphors, generally exhibit excellent performance, but their bulk crystal growth requires high temperatures, significantly limiting their development into large-area, thin, and flexible X-ray detection devices. Furthermore, many commercial scintillators, including thallium-doped CsI (CsI:Tl) and LaBr3:Ce, exhibit inherent hygroscopicity, posing additional challenges to device fabrication. Emerging lead-based perovskite nanocrystalline scintillators have successfully overcome the high-temperature growth requirement of traditional scintillators. They are solution-processable and can be synthesized on a large scale at low temperatures; however, the high toxicity of lead and the inherent instability of perovskites to moisture greatly limit their practical applications.

[0004] Therefore, it is necessary to develop a new type of X-ray scintillator that does not have the above-mentioned drawbacks. Summary of the Invention

[0005] Technical problems to be solved

[0006] To avoid the shortcomings of the prior art, this invention proposes a method for preparing and applying a copper-iodine cluster-based microcubic scintillator and thin film, which is a microcubic scintillator capable of generating ionizing radiation-excited emission.

[0007] Technical solution

[0008] A copper-iodine cluster-based microcubic scintillator, characterized by the chemical formula C 18 H 38 Cu4I6N4, structural formula is:

[0009]

[0010] A method for preparing the copper-iodine cluster-based microcubic scintillator, characterized in that: cuprous iodide, a synthesized quaternary ammonium salt, and polyvinylpyrrolidone are reacted at a heating temperature of 25-70°C to obtain the copper-iodine cluster-based microcubic scintillator.

[0011] A method for preparing a copper-iodine cluster-based flexible scintillator film using the copper-iodine cluster-based microcubic scintillator is characterized by: firstly, mixing the copper-iodine cluster-based microcubic scintillator, prepolymer or polymer monomer and curing agent or initiator evenly and performing degassing treatment for 10-30 min, then polymerizing at a heating temperature of 100-200℃, and cooling to room temperature to obtain a copper-iodine cluster-based flexible scintillator film.

[0012] The polymer matrix layer is polydimethylsiloxane, polymethyl acrylate, polyvinyl alcohol, polycarbonate, or polystyrene.

[0013] A method for applying the copper-iodine cluster-based flexible scintillator film, characterized in that: the copper-iodine cluster-based flexible scintillator film is placed before the acquisition optical path of the image acquisition component.

[0014] The image acquisition component is a digital camera or a photoelectric detector.

[0015] The photodetector is a PMT detector, a TFT photodiode sensor, a CCD sensor, a CMOS sensor, or an IGZO TFT sensor.

[0016] Beneficial effects

[0017] This invention proposes a method for preparing and applying a copper-iodine cluster-based microcubic scintillator and its thin film, which is a microcubic scintillator capable of generating ionizing radiation-excited emission. The microcubic scintillator comprises a copper-iodine cluster-based microcubic scintillator doped in a matrix layer. The chemical formula of the copper-iodine cluster-based microcubic scintillator is C0. 18 H 38 Cu4I6N4. It is noteworthy that the matrix layer is a polymer with high light transmittance, excellent chemical stability, and good mechanical properties (e.g., polydimethylsiloxane, polymethyl methacrylate, polyvinyl alcohol, polycarbonate, or polystyrene). Another aspect of the invention is an ionizing radiation imaging system comprising the aforementioned microcubic scintillator and a digital camera positioned behind the matrix layer doped with the microcubic scintillator. Optionally, the ionizing radiation imaging system further includes a photodetector attached to the matrix layer doped with the microcubic scintillator. The photodetector can be any of the following. Typically, the photodetector is a photomultiplier tube (PMT) detector, a thin-film transistor (TFT) photodiode sensor, a charge-coupled device (CCD) sensor, a complementary metal-oxide-semiconductor (CMOS) sensor, or an indium gallium zinc oxide (IGZO) TFT sensor. Attached Figure Description

[0018] Figure 1 Image a shows a field emission scanning electron microscope (SEM) image of the fabricated untreated microcubic scintillators, and the inset shows a high-resolution radio electron microscope (TEM) image of two fabricated untreated microcubic scintillators. Figure 1 b showed Figure 1 Transmission electron microscopy elemental distribution diagram of the two microcubic scintillators in the inset of Figure a. Figure 1 c shows the photoluminescence (PL) spectrum of the microcubic scintillator under xenon lamp illumination at a wavelength of 365 nm. The inset is a photograph of the sample under ultraviolet lamp illumination.

[0019] Figure 1 Figure d shows the changes in the photoluminescence (PL) quantum yield (QY) of the prepared microcubic scintillator after treatment for different times. Figure 1 e shows the phosphorescence lifetime of the processed microcubic scintillator. Figure 1 f shows the change in luminescence intensity when the treated microcubic scintillator is directly dispersed in water at different times.

[0020] Figure 2 a is a schematic diagram illustrating the basic design of a photoconductor for a copper-iodine cluster-based microcubic scintillator used for X-ray sensing. Figure 2 b is a schematic diagram of the current-voltage relationship of the photoconductor of the copper-iodine cluster-based microcube, recorded with and without X-ray irradiation.

[0021] Figure 3 a represents a dose rate of 278 μGy at a voltage of 50 kV. air s -1 The radioluminescence (RL) spectrum of the microcubic scintillator under X-ray irradiation, with the inset being an X-ray scintillation photograph of the sample;

[0022] Figure 3 b is a graph of the radiative emission (RL) intensity versus dose rate of the copper-iodine cluster-based microcubic scintillator;

[0023] Figure 3 c is the RL intensity diagram based on the scintillator under continuous irradiation and repeated excitation cycles.

[0024] Figure 4 Image a shows an X-ray scintillation of a flexible thin film prepared by a copper-iodine cluster-based microcubic scintillator (left: bright-field imaging; right: X-ray irradiation at 70 kV).

[0025] Figure 4 b is a schematic diagram of the simple real-time X-ray diagnostic imaging experimental device that we built ourselves.

[0026] Figure 4 c is an X-ray phase comparison image of the alarm clock chip recorded with a digital camera;

[0027] Figure 4 d refers to illustrations, i.e. Figure 4 Grayscale analysis was performed on the middle region of c to obtain the spatial intensity contrast of the image. By fitting the point spread function of the intensity profile, the spatial resolution was calculated to be 270μm.

[0028] Figure 4 e uses the prepared flexible X-ray scintillator film to image the line-to-card;

[0029] Figure 4 f and 4g are photographs of a nude mouse commonly used in medical experiments under bright field and X-ray irradiation, respectively;

[0030] Figure 4 h is an image obtained by magnifying the tail of a nude mouse photographed under X-ray irradiation. Detailed Implementation

[0031] The present invention will now be further described in conjunction with the embodiments and accompanying drawings:

[0032] The microcube scintillator that generates emission excited by ionizing radiation is disclosed in detail here first.

[0033] The microcubic scintillator comprises a cuprous iodide-based microcubic scintillator doped in a matrix layer. The chemical formula of the cuprous iodide-based microcubic scintillator is Ci. 18 H 38 Cu4I6N4.

[0034] In some exemplary microcube scintillators, the matrix layer is a polymer with high light transmittance, excellent chemical stability and good mechanical properties (e.g., polydimethylsiloxane, polymethyl methacrylate, polyvinyl alcohol, polycarbonate or polystyrene).

[0035] The microcubic scintillator of the present invention can respond to dose rates of 22 nGy air s -1 It responds to radiation.

[0036] Another ionizing radiation imaging system within the scope of this invention includes the aforementioned microcubic scintillator and a digital camera positioned behind a matrix layer doped with the microcubic scintillator. Optionally, the ionizing radiation imaging system further includes a photodetector attached to the matrix layer doped with the microcubic scintillator. The photodetector can be any one of a PMT detector, a TFT photodiode sensor, a CCD sensor, a CMOS sensor, or an IGZO TFT sensor.

[0037] Without further elaboration, we believe that those skilled in the art can utilize the present invention to the fullest extent based on the above description. Therefore, the following specific embodiments should be interpreted as merely illustrative and not as limiting the remainder of this disclosure in any way. All publications cited herein are incorporated herein by reference in their entirety.

[0038] Example 1: The microcubic scintillator comprises copper-iodine cluster-based microcubic cells.

[0039] Synthesis of 1-propyl-1,4-diazabicyclo[2.2.2]oct-1-onium (pr-ted)

[0040] First, 1,4-diazabicyclo[2.2.2]octane (5.6 g, 50 mmol) was dissolved in acetone (250 mL), and then 1-bromopropane (6.15 g, 50 mmol) was added dropwise to the vial under magnetic stirring. After mixing, the solution remained clear, and a colorless oily precipitate formed within one hour. The precipitate was collected by centrifugation, washed with ethyl acetate, and dried under vacuum. Its structural formula is...

[0041] Synthesis and Characterization of Cu4I6(pr-ted)2

[0042] The synthesis of Cu4I6(pr-ted)2 is carried out in two parts. The first part is the synthesis of Cu4I6(pr-ted)2 powder, the structural formula of which is... First, polyvinylpyrrolidone (PVP; 0.25 g) and ethanol (EtOH; 12.5 ml) were added to a two-necked flask (25 ml). The resulting mixture was heated to 70 °C with vigorous stirring until the PVP was completely dissolved. Then, CuI (0.0475 g, 0.25 mmol) was dispersed in a saturated potassium iodide solution (0.5 ml). The CuI / KI mixture was rapidly added to the PVP K88-96 / ethanol mixture. When the mixture turned into a clear yellow liquid, pr-ted (0.040 g, 0.25 mmol) was dispersed in 0.5 ml of ethanol. The pr-ted / ethanol mixture was then injected into the 70 °C CuI / KI / PVP mixture, and the flask was quickly transferred to an ice bath. Cu4I6(pr-ted)2 was centrifuged at 6000 rpm for 5 min to obtain microcubes, which were washed twice with ethanol and water, respectively. The resulting product was stored in 2 ml of ethanol. The second part is the post-processing of Cu4I6(pr-ted)2. First, the preserved product is ultrasonically dispersed in ethanol. Then, the resulting mixture is transferred to a 5ml glass bottle and placed in a vacuum drying oven to remove the ethanol and obtain dry Cu4I6(pr-ted)2 powder. The vacuum drying oven is then evacuated three times to remove oxygen and other substances inside, and nitrogen is introduced to protect the Cu4I6(pr-ted)2 powder at high temperature. The temperature is then raised to 200℃ and held for 90 minutes. Finally, the powder is cooled in a nitrogen atmosphere to obtain the final Cu4I6(pr-ted)2 powder.

[0043] Microcubes were imaged using a ZEISS Gemini SEM 300 scanning electron microscope with an accelerating voltage of 3 kV. A typical SEM image shows... Figure 1 In Figure a, it is shown to be a microcubic shape with an average size of 3 μm; the microcubic scintillator was TEM imaged using a FEI Talos F200X transmission electron microscope with an accelerating voltage of 200 kV and the elemental distribution map was obtained; the microcubic scintillator was characterized by powder X-ray diffraction using a Bruker D8 Advance X-ray diffractometer with Cu Kα radiation.

[0044] We investigated the possibility of using microcubic scintillators for green X-ray scintillation. More specifically, we measured the radiative emission of Cu₄I₆(pr-ted)₂ microcubic scintillators using a Zolix OmniFluo fluorescence spectrophotometer (Zolix Instruments CO.,LTD) equipped with a miniature X-ray source (MOXTEK, Inc.). This study included three commercially available bulk scintillators: PbWO₄, YAIO₃:Ce, and Bi₄Ge₃O₂. 12 Compare them.

[0045] Scintillation properties of different types of materials

[0046]

[0047] Flexible microcubic scintillators are prepared using standard thermosetting technology.

[0048] In brief, the first step involves vacuum degassing the PDMS prepolymer for 30 minutes. The second step involves dispersing the obtained Cu4I6(pr-ted)2 powder into a cyclohexane / ethanol mixed solution. This Cu4I6(pr-ted)2 powder / cyclohexane / ethanol mixture is then added to the vacuum-degassed PDMS prepolymer, and vacuum degassing is performed again to ensure complete evaporation of most of the solution. The third step involves adding PDMS curing agent to the mixture obtained in the second step, according to the PDMS prepolymer and curing agent ratio (10:1 by mass), and vacuum degassing for 30 minutes. Finally, the resulting mixture is poured into a polytetrafluoroethylene mold and cured at 200°C for 90 minutes. After curing, the mixture is cooled to room temperature in the oven to obtain a flexible microcubic scintillator film.

[0049] Figure 1 Figure d shows the changes in quantum yield (QY) of the synthesized Cu4I6(pr-ted)2 microcubic scintillator after treatment for different time periods. The test equipment used was a Hamamatsu C9920-02G quantum yield measurement system from Japan. Figure 1 e shows the phosphorescence lifetime of the post-treated Cu4I6(pr-ted)2 microcubic scintillator. Figure 1 f shows the change in luminescence intensity of post-treated Cu4I6(pr-ted)2 microcubic scintillators directly dispersed in water at different times.

[0050] Example 2: Fabrication of an X-ray photoconductor containing a microcubic scintillator

[0051] We constructed an X-ray light conductor ( Figure 2a) The presence of X-ray induced charge carriers in Cu4I6(pr-ted)2 microcubic scintillators was experimentally determined.

[0052] First, a 50 nm thick gold electrode was deposited on a silicon substrate consisting of a 300 nm SiO2 layer by thermal evaporation, with the size of the gold electrode controlled by using a shadow mask. Then, a Cu4I6(pr-ted)2 scintillator dispersed in ethanol was dropped between the two gold electrodes.

[0053] The current-voltage characteristics of the X-ray photoconductor were then determined under conditions of X-ray irradiation and without X-ray exposure. X-ray photon current was measured using a commercially available miniaturized X-ray tube (AMPEK) with a silver target and a maximum output power of 4W. The voltage was maintained at 50 kV, using only screw-in brass caps. The distance between the X-ray source and the X-ray photoconductor was approximately 1 cm. The current-voltage relationship of the X-ray photoconductor was measured using a Keithley 2450 digital source meter.

[0054] like Figure 2 As shown in b, the current through the X-ray detector increases with X-ray irradiation, which confirms the presence of X-ray induced charge carriers in the Cu4I6(pr-ted)2 microcube.

[0055] Example 3: Characterization of the X-ray detection performance of microcubic scintillators

[0056] Figure 3 a represents a micro-scale scintillator at 50 kV with a dose rate of 278 μGy. air s -1 The X-ray irradiation (RL) spectrum of the sample is shown in the inset, which is a radioluminescence photograph of the sample under X-ray irradiation.

[0057] The detection limit performance of Cu4I6(pr-ted)2 microcubic scintillators was demonstrated by exposing them to a dose rate range of 0.013–278 μGy. air s -1 The dose rate is determined from the X-ray photons emitted, and is controlled by adjusting the current and voltage of the X-ray source.

[0058] like Figure 3 As shown in b, the Cu4I6(pr-ted)2 microcubic scintillator exhibits a linear response to X-ray dose rate. It can detect 22 nGy. air s -1 The low dose rate of X-ray photons is lower than the medical radiation dose threshold (5.5 μGy) typically required for X-ray diagnostics. air s -1 It is 250 times lower.

[0059] The photostability of the Cu4I6(pr-ted)2 microcubic scintillator was further examined under continuous or repetitive X-ray irradiation cycles (114 cycles; excitation time interval = 30 s). Figure 3 c). It was found that X-ray induced radiative emission did not decrease with increasing illumination time or illumination cycle, indicating that the Cu4I6(pr-ted)2 microcubic scintillator is stable to X-ray photons.

[0060] In summary, the Cu4I6(pr-ted)2 microcubic scintillator of the present invention is highly sensitive to X-ray photons. Furthermore, since the Cu4I6(pr-ted)2 microcubic scintillator is photostable, the performance of the X-ray detector constructed from the Cu4I6(pr-ted)2 microcubic scintillator does not deteriorate under X-ray irradiation.

[0061] Example 4: Fabrication and characterization of an X-ray imaging system containing microcubic scintillators

[0062] First, we prepared a flexible transparent film by doping Cu4I6(pr-ted)2 microcubic scintillators into PDMS. For example... Figure 4 As shown in Figure a, the left image shows the text and graphics behind the film clearly visible through sunlight; the right image shows the film emitting a dazzling green light under X-ray irradiation. Figure 4 b is a schematic diagram of the simple real-time X-ray diagnostic imaging experimental device that we built ourselves. Figure 4 c is an X-ray phase comparison image of the alarm clock chip recorded with a digital camera; Figure 4 d refers to illustrations, i.e. Figure 4 Grayscale analysis was performed on the middle region of c to obtain the spatial intensity contrast of the image. By fitting the point spread function of the intensity profile, the half-width (FWHM) of the fitted curve was found to be 270μm, which means that the spatial resolution of the image is also 270μm. Figure 4 e uses the prepared flexible X-ray scintillator film to image the line-to-card; Figure 4 f and 4g are photographs of a nude mouse commonly used in medical experiments under bright field and X-ray irradiation, respectively; Figure 4 h is an image obtained by magnifying the tail of a nude mouse photographed under X-ray irradiation.

[0063] In view of these results, the Cu4I6(pr-ted)2 microcubic scintillator of the present invention can completely replace currently commercially available scintillators.

[0064] Other implementation methods

[0065] All features disclosed in this specification can be combined in any combination. Each feature disclosed in this specification can be replaced by an alternative feature having the same, equivalent, or similar purpose. Therefore, unless otherwise expressly stated, each disclosed feature is merely an instance of a series of equivalent or similar features.

[0066] Furthermore, based on the above description, those skilled in the art can readily determine the essential features of the present invention, and various changes and modifications can be made to adapt the invention to various uses and conditions without departing from the spirit and scope of the invention. Therefore, other embodiments are also within the scope of the claims.

Claims

1. A method for preparing a copper-iodine cluster-based flexible scintillator film using a copper-iodine cluster-based microcubic scintillator, characterized in that, Vacuum degassing of PDMS prepolymer for 30 minutes; Copper-iodine cluster-based microcubic scintillators were dispersed in a cyclohexane / ethanol mixed solution. The mixed solution of copper-iodine cluster-based microcubic scintillator powder / cyclohexane / ethanol was added to PDMS prepolymer that had just undergone vacuum degassing, and vacuum degassing was performed to obtain a mixture. According to the mass ratio of PDMS prepolymer to curing agent of 10:1, PDMS curing agent was added to the mixture and vacuum degassing was performed for 30 min. Finally, the resulting mixture was poured into a polytetrafluoroethylene mold and kept at 200℃ for 90 min for curing. After curing, it was cooled to room temperature in the oven to obtain a copper iodine cluster-based flexible scintillator film. The copper-iodine cluster-based microcubic scintillator has the chemical formula C. 18 H 38 Cu4I6N4, structural formula is: 。 2. A method for applying the copper-iodine cluster-based flexible scintillator thin film prepared by the method of claim 1, characterized in that: A copper-iodine cluster-based flexible scintillator film is placed in front of the acquisition optical path of the image acquisition component.

3. The application method according to claim 2, characterized in that: The image acquisition component is a digital camera or a photoelectric detector.

4. The application method according to claim 3, characterized in that: The photodetector is a TFT photodiode sensor, a CCD sensor, a CMOS sensor, or an IGZO TFT sensor.

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