Cuprous iodide complex single crystal as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of luminescent materials, and particularly relates to a cuprous iodide complex single crystal as well as a preparation method and application thereof. The invention discloses a cuprous iodide complex single crystal based on pyrimidine derivative ligand 4-Mepym, the chemical formula of the cuprous iodide complex is CuI (4-Mepym), the 4-Mepym is an organic ligand component, and the CuI is an inorganic component; the organic ligand is obtained by bridging two Cu (I) through double nitrogen atoms; the cuprous iodide complex single crystal is an orthorhombic system, and the cuprous iodide complex single crystal can be obtained from cuprous iodide and 4-methylpyrimidine through a method of combining solution diffusion with solvent volatilization. The cuprous iodide complex single crystal disclosed by the invention is used as a scintillator, a scintillator film is obtained through blade coating, dispensing and other technologies, and the scintillator film can perform clear imaging on the internal structure of a real object under X-ray irradiation and can also be used for three-dimensional dynamic imaging.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of luminescent materials, and particularly relates to a cuprous iodide complex single crystal as well as a preparation method and application thereof. BACKGROUND

[0002] X-ray imaging scintillators can convert high-energy radiation into low-energy ultraviolet-visible light, which is particularly important in various applications, including medical diagnosis, industrial flaw detection, nuclear power plants, space exploration, etc. Achieving the common improvement of the light yield, stability, environmental friendliness of the scintillator, and the uniformity and flexibility of the scintillator screen is an important challenge in this research field. Therefore, developing new high-performance X-ray imaging scintillators has great scientific and practical value.

[0003] Traditional inorganic scintillators, such as CsI:TI, LuAG:Ce, CdWO4 and YAG:Ce, have excellent energy resolution and high light yield, but the preparation process is complex, the synthesis temperature and vacuum conditions are high, which is neither convenient nor environmentally friendly. Organic scintillators have the advantages of scalability and solution processability, and can be manufactured at room temperature using simple procedures. However, due to limited effective atomic number, insufficient exciton utilization and non-radiative relaxation, the low X-ray attenuation ability of organic scintillators severely limits their development and future commercialization. Halide perovskites composed of heavy elements such as Cs, Pb, Br and I exhibit excellent performance due to their high efficient atomic number composition, high absorption coefficient and high photoluminescence quantum yield. However, the inevitable self-absorption effect, low stability and lead toxicity further hinder their practical application.

[0004] Halide cuprous complex combines the advantages of diverse electronic properties of coordination metal centers, tunable halide cuprous cluster structures and modifiable organic ligand molecules, and has great potential in developing new high-performance scintillators. In addition, the natural abundance and low toxicity of copper make copper-based compounds more attractive from the economic and environmental perspectives.

[0005] Common neutral halide cuprous complexes, combined through coordination bonds between Cu(I) and organic ligands, can form various charge-neutral inorganic clusters Cu m X m , which can be zero-dimensional (0D) molecular clusters, one-dimensional (1D) chains or two-dimensional (2D) layers, and have achieved high photoluminescence quantum efficiency (PLQY), but regardless of the type of inorganic modules (such as molecular clusters, chains or layers) or the dimensionality of the overall structure, their solubility and solution processability are poor, which greatly limits their practical application in large-scale production. In addition, ionic halide cuprous complexes, generally composed of [Cu m X m ]n, have high solubility and solution processability, but their photoluminescence quantum efficiency (PLQY) is low. m X n ]n, have high solubility and solution processability, but their photoluminescence quantum efficiency (PLQY) is low.-n+m Negatively charged inorganic clusters and L n-m Composed of organic cations, containing only ionic bonds. Due to their pure ionic structure, they are generally more stable than neutral cuprous halide complexes, but their optical emission is weaker, exhibiting lower internal quantum efficiency (IQYs).

[0006] Currently, research focuses on multi-focusing pyridine ligands (such as 4-methylpyridine), but its limitations are significant. Typical pyridine derivative complexes (such as CuI(4-me-py)) have a PLQY of only 38.3%, indicating insufficient exciton utilization and low efficiency under deep blue light. Pyridine ligands are difficult to achieve efficient emission at short wavelengths (<450nm), limiting multicolor imaging applications and limiting spectral modulation. Furthermore, most cuprous halide complex scintillators are used in bulk single-crystal form after grinding, resulting in relatively large particle sizes. Due to poor dispersibility, lack of suitable solvents, and low equivalent density of the scintillator material, it is often difficult to prepare uniform, transparent, and particle-free thin films. This light scattering leads to reduced resolution and affects imaging quality. Summary of the Invention

[0007] This invention provides a single crystal of cuprous iodide complex, its preparation method, and its application in the fabrication of photoluminescent and scintillator materials. The single crystal of cuprous iodide complex provided by this invention is a novel structure based on pyrimidine derivative ligands. Using the single crystal of cuprous iodide complex as a scintillator, a scintillator film is obtained by scraping, achieving highly efficient green luminescence under X-ray irradiation. It can clearly image the internal structure of various physical objects and can be used for three-dimensional dynamic imaging, effectively eliminating artifact problems.

[0008] The technical solution adopted in this invention is as follows:

[0009] In a first aspect, the present invention provides a single crystal of a cuprous iodide complex, wherein the chemical formula of the cuprous iodide complex crystal is CuI(4-Mepym), where 4-Mepym, or 4-methylpyrimidine, is the organic ligand component, and cuprous iodide CuI represents the inorganic component; the organic ligand is a charge-neutral complex formed by bridging two Cu(I) atoms with two nitrogen atoms; the single crystal of the cuprous iodide complex is orthorhombic with space group p-1. α=83.757(3)°, β=88.908(3)°, γ=88.695(2)°,

[0010] Secondly, the present invention provides a method for preparing the above-mentioned cuprous iodide complex single crystal, wherein the cuprous iodide complex single crystal is obtained by solution diffusion combined with solvent evaporation of cuprous iodide and 4-methylpyrimidine; as a preferred embodiment of the present invention, the preparation method specifically includes the following steps:

[0011] Step S1: At room temperature, cuprous iodide is dissolved in acetonitrile to prepare a cuprous iodide acetonitrile solution, wherein the concentration of cuprous iodide in the cuprous iodide acetonitrile solution is 0.05–0.1 mmol / mL; 4-methylpyrimidine is dissolved in methanol to prepare a mixed ligand solution, wherein the concentration of the ligand is 0.09–0.11 mol / mL.

[0012] Step S2: A layer of acetonitrile is placed on top of the completely dissolved cuprous iodide acetonitrile solution, and then the mixed ligand solution is slowly added to the cuprous iodide acetonitrile solution to prepare a mixed solution; the molar ratio of cuprous iodide to 4-methylpyrimidine is (0.45~1.11):1;

[0013] Step S3: Seal the opening with aluminum foil and make small holes in the aluminum foil with a needle. Crystallize using diffusion and volatilization methods. The resulting crystal is a single crystal of cuprous iodide complex.

[0014] The aforementioned cuprous iodide complex single crystal exhibits a yellow-green emission spectrum in the green light band under ultraviolet light, with an emission spectrum range of 390 nm to 700 nm and an optimal emission peak at 528 nm. Its lifetime under room-temperature ultraviolet light is 1.28 μs, and its luminescence quantum efficiency is 64.93%. Therefore, this single crystal can be used to fabricate photoluminescent materials. Thirdly, this invention also provides the application of the aforementioned cuprous iodide complex single crystal in the fabrication of photoluminescent materials, including ultraviolet-excited fluorescent materials or visible-light-responsive luminescent materials. For example, grinding the cuprous iodide complex single crystal into powder and then uniformly mixing it with epoxy resin and curing it can serve as a wavelength conversion layer for ultraviolet LED devices, generating high-brightness yellow-green fluorescence under 365–450 nm ultraviolet light excitation, thereby improving the color gamut and visual effect of the light-emitting device.

[0015] The above-mentioned cuprous iodide complex single crystal has a high photon yield of 24257±198 photons / MeV under X-rays. Therefore, in a fourth aspect, the present invention also provides the application of the above-mentioned cuprous iodide complex single crystal in the fabrication of scintillator materials.

[0016] Fifthly, the present invention also provides a scintillator ink, which is prepared by grinding the above-mentioned cuprous iodide complex single crystals, mixing them with water or an organic solvent to form a suspension, and then fully mixing them with a polymer solution. The organic solvent is dichloromethane, and the suspension concentration is 50–200 mg / mL. Preferably, the step of fully mixing with the polymer solution includes: adding the suspension to the polymer solution and thoroughly ultrasonically stirring. In the prepared scintillator ink, the mass percentage of the cuprous iodide complex powder in the solution after mixing all the ink components is 10%–40%. The polymer solution is a solution formed by dissolving any one of polyvinyl alcohol, polydimethylsiloxane, or polymethyl methacrylate in water, and the concentration of the polymer solution is 50–200 mg / mL.

[0017] Sixthly, the present invention provides a scintillator film, which is obtained by a blade coating method using the aforementioned scintillator ink; preferably, the thickness of the scintillator film is 150–250 μm; as a preferred preparation method of the scintillator film of the present invention, the preparation method includes the steps of: coating scintillator ink onto a glass substrate by a blade coating method, allowing it to air dry naturally or dry at a temperature below 100°C, and then peeling off the film to obtain a flexible scintillator film. As a more preferred embodiment, the blade coating can be prepared by blade coating onto a glass substrate using microelectronic printing to obtain a scintillator coating; when using microelectronic printing for blade coating, the specific steps are as follows: injecting scintillator ink into the ink sac of a microelectronic printer, printing the ink onto the glass substrate by the pressure of a pump to obtain a scintillator coating, and then scraping it off after allowing it to air dry at room temperature to obtain a scintillator film.

[0018] In a seventh aspect, the present invention provides the application of the above-mentioned scintillator film in X-ray imaging. The X-ray imaging application uses an X-ray imaging platform to construct an X-ray imaging platform, with the above-mentioned scintillator film as a substrate, and an object placed on top of the film. X-rays are irradiated onto the surface of the film, reflected by a prism, and captured by a camera to obtain the entire X-ray image.

[0019] Beneficial effects: This invention provides a single crystal of cuprous iodide complex, which utilizes the steric hindrance effect and electron-donating ability of methyl groups. Pyrimidine ligands, such as pyrimidine Pym and its methyl derivatives, have a diazonium heterocyclic structure, which can provide more coordination modes and electronic regulation sites. The higher ligand field splitting energy is beneficial for blue-shift emission. The electronic effects of methyl substituents, such as electron-donating ability and steric hindrance effect, can finely adjust the charge distribution of Cu-I clusters, thereby improving the luminescence performance of cuprous iodide complex. The emission intensity of cuprous iodide complex single crystals as scintillators remains almost unchanged under X-rays, indicating high radiation resistance. They also exhibit a short luminescence lifetime, which is beneficial for their dynamic imaging applications under X-ray excitation. The cuprous iodide complex scintillator film prepared based on the above-mentioned cuprous iodide complex emits yellow-green light under ultraviolet excitation and green light under X-ray excitation. Furthermore, the light yield of the prepared scintillator is 24257±198 photons / MeV, comparable to the 25000 photons / MeV of LuAG:Ce, which can achieve 22 lp mm for both static and three-dimensional dynamic imaging. -1 High spatial resolution. Attached Figure Description

[0020] Figure 1 The structural diagram of the [CuI(L)] (L=Pym) crystal prepared for Comparative Example 1;

[0021] Figure 2 The structural diagram of the [CuI(L)] (L=4-Mepym) crystal prepared in Example 1;

[0022] Figure 3 The images, from left to right, show actual photographs of the crystals prepared in Example 1 under natural light and ultraviolet light.

[0023] Figure 4 The actual and simulated XRD patterns of the [CuI(L)] (L=Pym,4-Mepym) crystals in Comparative Example 1 and Example 1 are shown.

[0024] Figure 5 The excitation and emission spectra of the [CuI(L)] (L=Pym,4-Mepym) crystals in Comparative Example 1 and Example 1 are shown.

[0025] Figure 6 The lifetime decay curves of [CuI(L)] (L=Pym,4-Mepym) crystals in Comparative Example 1 and Example 1 are shown.

[0026] Figure 7 The photochemical properties of the [CuI(L)] (L=Pym,4-Mepym) crystals in Comparative Example 1 and Example 1;

[0027] Figure 8The photoluminescence quantum efficiency of the [CuI(L)] (L=Pym,4-Mepym) crystals in Comparative Example 1 and Example 1;

[0028] Figure 9 The radiation stability spectra of the [CuI(L)] (L=Pym,4-Mepym) crystals in Comparative Example 1 and Example 1 are shown.

[0029] Figure 10 X-ray imaging images of the [CuI(L)] (L=4-Mepym) powder scintillator film prepared in Example 1; wherein (a) is an internal structure imaging image of a small sea snail assembly with small screws placed inside; and (b) is an internal structure imaging image of an earphone.

[0030] Figure 11 The X-ray resolution test results are for the [CuI(L)] (L=4-Mepym) scintillator thin film prepared in Example 4;

[0031] Figure 12 These are photos taken at 30° intervals during the process of rotating the commercially available audio-visual buzzer from 0° to 180° in Test Example 2.

[0032] Figure 13 This is a 3D reconstruction of the commercially available audio-visual buzzer in Test Example 2;

[0033] Figure 14 Cross-sectional views of the metal, glass, and plastic components of the commercially available sound and light buzzer in Test Example 2 from different directions;

[0034] Figure 15 The grayscale distribution curves are for the three components of the commercially available sound and light buzzer in Test Example 2: metal, glass, and plastic. Detailed Implementation

[0035] The technical solution of the present invention will be described in detail below, but the scope of protection of the present invention is not limited to the embodiments described. In the following embodiments, the raw materials and reagents were directly purchased as commercial chemical reagents without further purification.

[0036] Acetonitrile: Guoyao, AR≥99%; KI: Guoyao, AR powder; Water: Wahaha; Methanol: Guoyao, AR≥99.5%; 4-Methylpyrimidine: ADAMAS, 98%; Pyrimidine: Adamas reagent, 99%; CuI: Adamas reagent, 99%;

[0037] Equipment model and manufacturer:

[0038] X-ray tube system: Mini-X2, Amptek; Mini-X2 is an X-ray tube system that includes an X-ray tube, power supply, control electronics, and USB communication with a computer. Amptek is the company name.

[0039] Microelectronic printer: Prtronic Scientific3 microelectronic printer from Mifang Technology.

[0040] Comparative Example 1

[0041] Comparative Example 1 provides a preparation process for a single crystal of cuprous iodide complex, specifically a synthesis process for a [CuI(L)] (L=Pym) crystal. The specific synthesis process is as follows: In a 20 ml glass bottle, CuI (0.2 mmol, 38.0 mg) was completely dissolved in 2 ml of saturated potassium iodide solution to prepare a CuI saturated potassium iodide solution. In a 10 ml glass bottle, Pym (16 μL, 0.2 mmol) was completely dissolved in 2 ml of methanol to prepare a ligand methanol solution. 6 ml of acetonitrile was added dropwise to the top of the prepared CuI saturated potassium iodide solution, and the ligand methanol solution was slowly added dropwise to the CuI saturated potassium iodide solution. The glass bottle was sealed tightly with aluminum foil, and a hole was made in the aluminum foil using a needle. After standing for 1–2 days, elongated crystals were obtained through solution diffusion and volatilization, which are the single crystals of the cuprous iodide complex. The structural formula of pyrimidine Pym is shown below:

[0042]

[0043] Example 1

[0044] Example 1 also provides a preparation process for a single crystal of cuprous iodide complex, specifically a synthesis process for a [CuI(L)] (L=4-Mepym) crystal. The specific synthesis process is as follows: In a 20 ml glass bottle, CuI (0.2 mmol, 38.0 mg) was completely dissolved in 2 ml of acetonitrile to prepare a CuI acetonitrile solution. In a 10 ml glass bottle, 4-Mepym (19 μL, 0.2 mmol) was completely dissolved in 2 ml of methanol to prepare a ligand methanol solution. 10 ml of acetonitrile was added dropwise to the top of the prepared CuI acetonitrile solution, and the ligand methanol solution was slowly added dropwise to the CuI acetonitrile solution. The glass bottle was sealed tightly with aluminum foil, and a hole was made in the aluminum foil using a needle. After standing for 1–2 days, clustered crystals obtained through solution diffusion and evaporation were obtained, which is the single crystal of the cuprous iodide complex prepared in Example 1. The structural formula of 4-methylpyrimidine 4-Mepym is shown below:

[0045]

[0046] In both Comparative Example 1 and Example 1 above, solution diffusion and volatilization methods were used to grow crystals in CuI saturated potassium iodide solution / CuI acetonitrile solution. Different milliliters of acetonitrile were used in the intermediate layer. In both cases, [CuI(L)] (L=Pym,4-Mepym) crystals, i.e., cuprous iodide complex scintillator single crystals, were prepared.

[0047] The [CuI(L)] (L=Pym, 4-Mepym) crystals prepared in Comparative Example 1 and Example 1 were characterized and tested, and the results are as follows:

[0048] Figure 4 The actual and simulated XRD patterns of the [CuI(L)] (L=Pym, 4-Mepym) crystals prepared in Comparative Example 1 and Example 1 are shown. The comparison revealed that the peak positions at various angles were consistent and there were no extra impurity peaks, indicating that the structure of the synthesized [CuI(L)] (L=Pym, 4-Mepym) crystal was consistent with the test results and had high purity without other impurities.

[0049] Figure 5 The excitation and emission spectra of the [CuI(L)] (L=Pym, 4-Mepym) crystals prepared in Comparative Example 1 and Example 1 were obtained. The instrument used for the ultraviolet emission spectrum test was an Edinburgh FLS980 transient spectrometer, and the parameters of Comparative Example 1 were as follows: measurement range: 380~700nm, excitation: 384nm, emission: 496nm, slit: 1.0; Figure 4 This indicates that under the optimal excitation of a 439nm xenon lamp light source, the emission spectrum of the [CuI(L)] (L=Pym) crystal in Comparative Example 1 ranges from 380nm to 700nm, with the optimal emission peak at 508nm, exhibiting green light emission. Figure 4 This indicates that under optimal excitation by a 358nm xenon lamp light source, the emission spectrum of the [CuI(L)] (L=4-Mepym) crystal in Example 1 ranges from 380nm to 700nm, with the optimal emission peak at 528nm, exhibiting green light emission; measurement range: 380~700nm, excitation: 439nm, emission: 508nm, slit: 1.0.

[0050] Figure 6The lifetime decay curves of the [CuI(L)] (L=Pym,4-Mepym) crystals prepared in Comparative Example 1 and Example 1 are shown. The lifetime decay curves were obtained by testing with the 375nm laser on the Edinburgh FLS980 transient spectrometer and fitting the curves using the instrument's built-in fitting method. The time required for the fluorescence intensity of the [CuI(L)] (L=Pym) crystal in Comparative Example 1 to drop to 1 / e of the maximum fluorescence intensity at excitation was 0.55 microseconds. The time required for the fluorescence intensity of the [CuI(L)] (L=4-Mepym) crystal in Example 1 to drop to 1 / e of the maximum fluorescence intensity at excitation was 1.28 microseconds.

[0051] Figure 7 The photon yield of the [CuI(L)] (L=Pym, 4-Mepym) crystals prepared in Comparative Example 1 and Example 1 is shown. Photon yield data acquisition method: Under the same test conditions, using X-rays as the excitation source, the X-ray emission spectra of the same volume of standard reference LuAG:Ce and the [CuI(L)] (L=Pym, 4-Mepym) crystals prepared in Comparative Example 1 and Example 1 were measured. The photon yield was then calculated using integration and formulas. The photon yield of Comparative Example 1 under X-rays was calculated to be 4500 photons / MeV, the photon yield of Example 1 was 24257±198 photons / MeV, and the photon yield of the scintillator sample LuAG:Ce under X-rays was 25000 photons / MeV. It can be seen that the photon yield of the [CuI(L)] (L=Pym, 4-Mepym) crystal prepared in Example 1 of this application is comparable to that of the scintillator sample LuAG:Ce.

[0052] Figure 8 To determine the photoluminescence quantum efficiency (PLQY) of the [CuI(L)] (L=Pym, 4-Mepym) crystals prepared in Comparative Example 1 and Example 1, an Edinburgh FLS980 transient spectrometer and integrating sphere were used for testing. The photoluminescence quantum efficiency was obtained by comparing the results with a standard white board and integrating the results using the instrument's built-in integration method. The results showed that the photoluminescence quantum efficiency of the [CuI(L)] (L=Pym) crystal prepared in Comparative Example 1 was 25.98%, and that of the [CuI(L)] (L=4-Mepym) crystal prepared in Example 1 was 64.93%.

[0053] Figure 9The radiation stability spectra of the [CuI(L)] (L=Pym,4-Mepym) crystals prepared in Comparative Example 1 and Example 1 are shown. By continuously irradiating the above scintillator material with a high dose of 4.8 Gy X-rays for 1000 s, it was found that its emission intensity under X-rays remained almost unchanged, indicating high radiation resistance.

[0054] In summary, the cuprous iodide complex [CuI(L)] (L=pym) crystal prepared in Comparative Example 1 exhibits a green emission spectrum under both ultraviolet and X-ray conditions, ranging from 390 nm to 700 nm, with an optimal emission peak at 508 nm. Its lifetime under room temperature ultraviolet light is 0.55 μs, its luminescence quantum efficiency is 25.81%, and its photon yield under X-rays is 4500 photons / MeV. The cuprous iodide complex [CuI(L)] (L=4-Mepym) crystal prepared in Example 1 also exhibits a green emission spectrum under both ultraviolet and X-ray conditions, ranging from 390 nm to 700 nm, with an optimal emission peak at 528 nm. Its lifetime under room temperature ultraviolet light is 1.28 μs, its luminescence quantum efficiency is 64.93%, and its photon yield under X-rays is 24257±198 photons / MeV.

[0055] The [CuI(L)] (L=Pym) crystal prepared in Comparative Example 1 has the following structure: Figure 1 As shown, the CuI core bond length is between the former two. Exhibiting moderate distortion. In this invention, unsubstituted pyrimidines are coordinated symmetrically with a bidentate structure, forming a highly planar dimer. The hydrogen bond network extends into a three-dimensional framework, suppressing nonradiative transitions. The product [CuI(L)] (L = 4-Mepym) crystal prepared in Example 1 has the following structure. Figure 2 As shown, CuI has higher nucleus symmetry. Near-tetrahedral coordination is formed. In this invention, 4-methylpyrimidine is coordinated in a nearly planar manner (the angle between the ring plane and Cu-I is <30°). The methyl group is located at the 4th position, which has a higher electron cloud density, enhancing its electron-donating ability.

[0056] Example 2

[0057] Example 2 also provides a preparation process for a single crystal of a cuprous iodide complex scintillator, specifically a synthesis process for a [CuI(L)] (L=4-Mepym) crystal. The specific synthesis process is as follows: In a 20 ml glass bottle, CuI (0.12 mmol, 23.0 mg) is completely dissolved in 2 ml of saturated potassium iodide solution to prepare a CuI saturated potassium iodide solution. In a 10 ml glass bottle, 4-Mepym (19 μL, 0.2 mmol) is completely dissolved in 2 ml of methanol to prepare a ligand methanol solution. 10 ml of acetonitrile is then added dropwise to the top of the prepared CuI saturated potassium iodide solution. The prepared ligand methanol solution is then slowly added dropwise to the CuI saturated potassium iodide solution. The glass bottle is sealed tightly with aluminum foil, and a hole is made in the aluminum foil using a needle. After standing for 1–2 days, the clustered crystals obtained through solution diffusion and evaporation are the cuprous iodide complex scintillator.

[0058] Example 2 used the same method as Example 1, only changing the concentration of CuI. At a concentration of 0.12 mmol, [CuI(L)] (L=4-Mepym) crystals, i.e., cuprous iodide complex scintillator single crystals, could also be prepared.

[0059] Example 3

[0060] Example 3 provides a method for preparing a cuprous iodide complex scintillator powder according to the present invention, specifically the synthesis process of a [CuI(L)] (L=4-Mepym) scintillator powder. The specific process includes: taking the microcrystals from Example 1 and grinding them using an agate mortar and pestle. After initially breaking the single crystals into small fragments, a small amount is placed in the mortar and ground with the pestle in a vertical, circular motion, gradually applying force to refine the powder. Intermittent operation is performed during the process to prevent overheating, and adhering powder is continuously scraped off to ensure uniformity. Finally, the powder is sieved through a 200-mesh sieve to obtain the desired particle size, carefully collected, labeled, and stored.

[0061] To ensure the purity of the powder, the XRD test results of the microcrystalline ground powder were compared with the simulated structure data of the single crystal. Figure 4 The XRD comparison diagrams show that the XRD test results of the powder from the crystal grinding process are consistent with the simulated structure data of the single crystal.

[0062] Example 4

[0063] Example 4 provides a specific process for preparing scintillator ink and scintillator film from cuprous iodide complex powder. The specific preparation process includes: adding 1.2g of polyvinyl alcohol (PVA) to 10ml of water, stirring thoroughly in a sand bath at 90°C until completely dissolved, and preparing a 120mg / ml PVA aqueous solution, which is colorless and transparent. Taking 40mg of the cuprous iodide complex powder described in Example 3, adding 0.6ml of water, and after thorough ultrasonic dispersion, adding 1.2ml of the prepared polyvinyl alcohol (PVA) aqueous solution, and stirring thoroughly for 12h to ensure thorough dispersion, a scintillator ink with a certain viscosity is prepared. Then, the scintillator ink is coated onto a glass substrate using a microelectronic printer to obtain a scintillator coating, and after evaporation and drying at room temperature for 24h, a [CuI(L)] (L=4-Mepym) powder scintillator film with a thickness of 200μm is obtained. Finally, the film is separated from the glass substrate using a utility knife.

[0064] Example 4 uses cuprous iodide complex powder to prepare scintillator film. The powder obtained by sieving through a 200-mesh sieve is of the required particle size. The powder size is uniform and the final product is a uniform, semi-transparent scintillator film without any grainy texture.

[0065] Test Example 1

[0066] X-ray static imaging: An X-ray imaging platform was constructed, utilizing a Mini-X2 as the X-ray tube system. The system consisted of a Mini-X2 X-ray tube (Amptek Inc.) as the excitation source, a charge-coupled device (CCD) camera (Nikon D850), a multi-fiber spectrometer, and the camera itself. The target material for the Mini-X2 X-ray tube was Au, P max =4W, V max =50kV, I max =80μA, X-ray source distance 3cm from scintillator film. Specifically, during the test, the X-ray source emission current was 70μA, the voltage was 50kV, and the X-ray source distance was 3cm from the scintillator film.

[0067] Using the [CuI(L)] (L=4-Mepym) scintillator film prepared in Example 4 as a substrate, the actual object was placed on the film. X-rays irradiated the surface of the film. The X-rays that passed through the chip, the small sea snail and the inside of the earphone were absorbed by the microcrystalline scintillator film and emitted green visible light. After being reflected by a prism, the images of the chip, the small sea snail and the earphone's internal structure information were obtained by the camera. Figure 10 Figures (a) and (b) are images of the internal structure of a small conch shell, a small screw, and an earphone, respectively.

[0068] During resolution testing, the wire pair cards were also placed on the thin film surface, and the resolution was obtained through an X-ray imaging system. In operation, the small seashell, screw, and earphone were replaced with wire pair cards. The standard resolution wire pair card image is shown below. Figure 11 As shown, the imaging resolution is as high as 22 lp mm. -1 .

[0069] The results of Test Example 1 confirm that the scintillator film prepared by the method of the present invention can be used for biological and industrial X-ray imaging, and can realize imaging of the internal structural information of chip objects.

[0070] Test Example 2

[0071] Three-dimensional dynamic X-ray imaging: An X-ray imaging platform was constructed, utilizing a Mini-X2 as the X-ray tube system. The system consists of a Mini-X2 X-ray tube (Amptek Inc.) as the excitation source, a charge-coupled device (CCD) camera (Nikon D850), a multi-fiber spectrometer, and the camera itself. The target material for the Mini-X2 X-ray tube is Au, P max =4W, V max =50kV, I max =80μA, X-ray source distance 3cm from scintillator film. Specifically, during the test, the X-ray source emission current was 70μA, the voltage was 50kV, and the X-ray source distance was 3cm from the scintillator film.

[0072] Using the [CuI(L)] (L=4-Mepym) scintillator film prepared in Example 4 as a substrate, the object was placed on top of the film. X-rays irradiated the surface of the film. The X-rays that passed through the object were absorbed by the powder scintillator film and emitted green visible light. After being reflected by a prism, the light was captured by a camera to obtain an image of the internal structure information.

[0073] To verify the feasibility of 3D image reconstruction, a commercially available acoustic-optical buzzer was selected as the test object. It was placed on a rotating stage perpendicular to the X-ray beam direction for multi-angle 2D projection imaging. During the 5° rotation of the buzzer from 0° to 180°, images were taken every 5°, for a total of 37 images. Then, dark field and background images were taken, for a total of 39 images. Using AVIZO software to process the projection data, a 3D reconstruction model composed of a series of Z-axis slices was successfully constructed, accurately reproducing the surface contours and fine internal structure of the device. Figure 12The images taken every 30° rotation (from 0° to 180°) of a commercially available audible and visual buzzer demonstrate that, thanks to the high spatial resolution of the thin film, the reconstructed model can achieve depth resolution based on material density differences. Even with the camera rotating at 360° / s, no significant ghosting was observed in the dynamic X-ray images of threads, wires, and resistance wires. This excellent performance is attributed to the inherent rapid decay characteristics and high-intensity X-ray response of the CuI(4-Mepym) scintillator, strongly confirming its high-resolution dynamic imaging capabilities.

[0074] Through the Figure 13 The three-dimensional reconstruction image of a commercially available audio-visual buzzer obtained from the image was subjected to tomographic slicing to obtain, as shown in the image. Figure 14 The cross-sectional image shown is segmented to extract grayscale distribution curves, which clearly identify the density gradient characteristics of the metal, glass, and plastic components. Figure 14 As shown, from left to right, these are cross-sectional views of the three components of a commercially available sound and light buzzer: metal, glass, and plastic, taken from different directions. Figure 15 The figure shows the grayscale distribution curves of the metal, glass, and plastic components of commercially available sound and light buzzers.

[0075] The results of Test Example 2 confirm that the scintillator film prepared by the method of the present invention can be used for three-dimensional dynamic imaging of biological and industrial X-rays. This multi-dimensional characterization method realizes the simultaneous visualization of the internal structure and surface morphology of the device, opening up a new solution for the development of low-dose X-ray imaging technology.

[0076] As described above, although the invention has been shown and described with reference to specific preferred embodiments, it should not be construed as limiting the invention itself. Various changes in form and detail may be made without departing from the spirit and scope of the invention.

Claims

1. A single crystal of a cuprous iodide complex, wherein the chemical formula of the cuprous iodide complex crystal is CuI(4-Mepym), where 4-Mepym is the organic ligand component and CuI is the inorganic component; the organic ligand is a bridging of two Cu(I) atoms via two nitrogen atoms; the single crystal of the cuprous iodide complex is orthorhombic with space group p-1. α=83.757(3)°, β=88.908(3)°, γ=88.695(2)°, 2. The method for preparing single crystals of the cuprous iodide complex according to claim 1, characterized in that, The cuprous iodide complex single crystal was obtained by a combination of solution diffusion and solvent evaporation of cuprous iodide and 4-methylpyrimidine.

3. The preparation method according to claim 2, characterized in that, The preparation method specifically includes the following steps: Step S1: At room temperature, cuprous iodide is dissolved in acetonitrile to prepare a cuprous iodide acetonitrile solution, wherein the concentration of cuprous iodide in the cuprous iodide acetonitrile solution is 0.05–0.1 mmol / mL; 4-methylpyrimidine is dissolved in methanol to prepare a mixed ligand solution, wherein the concentration of the ligand is 0.09–0.11 mol / mL. Step S2: A layer of acetonitrile is placed on top of the completely dissolved cuprous iodide acetonitrile solution, and then the mixed ligand solution is slowly added to the cuprous iodide acetonitrile solution to prepare a mixed solution; the molar ratio of cuprous iodide to 4-methylpyrimidine is (0.45~1.11):1; Step S3: Seal the opening with aluminum foil and make small holes in the aluminum foil with a needle. Use diffusion and volatilization methods to crystallize the resulting crystal, which is a single crystal of cuprous iodide complex.

4. The application of the cuprous iodide complex single crystal according to claim 1 in the fabrication of photoluminescent materials.

5. The application of the cuprous iodide complex single crystal according to claim 1 in the fabrication of scintillator materials.

6. A scintillator ink, characterized in that, The scintillator ink is prepared by grinding the single crystal of the cuprous iodide complex described in claim 1, first mixing it with water or an organic solvent to form a suspension, and then thoroughly mixing it with a polymer solution. The organic solvent is dichloromethane, and the suspension concentration is 50-200 mg / mL. In the prepared scintillator ink, the mass percentage of the cuprous iodide complex powder in the solution after mixing all the above ink components is 10%-40%. The polymer solution is a solution formed by dissolving any one of polyvinyl alcohol, polydimethylsiloxane, or polymethyl methacrylate in water, and the concentration of the polymer solution is 50-200 mg / mL.

7. A scintillator film, said scintillator film being obtained by a blade coating method from the scintillator ink of claim 6.

8. A scintillator thin film as described in claim 7, characterized in that, The thickness of the scintillator film is 150–250 μm.

9. The method for preparing the scintillator thin film according to claim 7, characterized in that, The preparation method includes the following steps: coating scintillator ink onto a glass substrate by a scraping method, allowing it to air dry naturally or dry at a temperature below 100°C, and then peeling off the film to obtain a flexible scintillator film.

10. The application of the scintillator thin film according to claim 7 in X-ray imaging, characterized in that, The X-ray imaging includes static imaging and three-dimensional dynamic imaging. The application steps include: constructing an X-ray imaging platform, using the above-mentioned scintillator film as a substrate, placing the object on top of the film, irradiating the surface of the film with X-rays, reflecting them through a prism, and then capturing them with a camera to form an X-ray image.

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