High spatial resolution X-ray scintillator based on two-dimensional copper(I) iodide halide

Abstract

The present invention provides a high spatial resolution X-ray scintillator based on two-dimensional copper (I) iodide halide. The entire preparation process of the high spatial resolution X-ray scintillator based on two-dimensional copper (I) iodide halide provided by the present invention has mild conditions, does not involve highly toxic and highly polluting organic reagents, etc., is simple to operate and environmentally friendly. The high spatial resolution X-ray scintillator based on two-dimensional copper (I) iodide halide provided by the present invention has good scintillation performance and good stability, and can achieve high-resolution X-ray imaging.

Description

Technical Field

[0001] The invention belongs to the technical field of scintillation materials, and in particular relates to a high spatial resolution X-ray scintillator based on two-dimensional copper (I) iodide halides. Background Art

[0002] X-ray scintillators are a class of materials that can convert high-energy X-rays into lower-energy visible light (ultraviolet, visible or infrared). Since the first scintillator was developed in 1896, they have been widely used in detection fields such as medical diagnosis, security inspection and non-destructive material testing. So far, the most developed scintillators are inorganic materials because of their extremely high thermal stability. But inorganic materials still have some problems, such as the strict conditions required for preparation, high toxicity, hygroscopicity and fragility. Recently, lead-based perovskites have demonstrated their great potential in this field, with a light yield of more than 101,944MeV -1 , its spatial resolution reaches 16.6lp mm -1 Due to the instability and toxicity of lead-based perovskites, the application of lead-free metal halides with high photoluminescence efficiency in scintillators has attracted great attention.

[0003] For practical applications of scintillator materials, people should not only pay attention to light yield and detection limit, but also spatial resolution, because it directly leads to the clarity of the image. It is well known that the transparency of the sample and the scattering of light are the two main factors affecting the spatial resolution of the scintillator. For example, the spatial resolution of the commercial inorganic scintillator CsI:Tl is 10lp mm -1 , although it has a higher light yield (54,000photon MeV -1 ), but low spatial resolution and the toxicity of the material itself have limited its use in X-ray imaging. Summary of the invention

[0004] The purpose of the present invention is to provide a two-dimensional Cu(I) organic-inorganic hybrid metal halide scintillator and apply it to X-ray scintillation imaging.

[0005] In a first aspect, the present invention provides a Cu(I)-based metal halide scintillator having a structural formula of (CISDM)4[Cu4I8]·2H2O;

[0006] CISDM stands for cis-2,6-dimethylmorpholine, with the molecular formula C6H 13 NO.

[0007] In some technical solutions, the Cu(I)-based metal halide scintillator is a colorless and transparent flaky crystal.

[0008] In some technical solutions, the crystal structure of the Cu(I)-based metal halide scintillator is as follows: Figure 1 shown.

[0009] In some technical solutions, the PXRD spectrum of the Cu(I)-based metal halide scintillator is as follows: Figure 3 shown.

[0010] In some technical solutions, the crystallographic parameters of the Cu(I)-based metal halide scintillator are as shown in Table 1.

[0011] In a second aspect, the present invention provides a method for preparing the above-mentioned Cu(I)-based metal halide scintillator, comprising the following steps:

[0012] 1) Resuspend cis-2,6-dimethylmorpholine C6H 13 NO and CuI are dissolved in the solvent to form a transparent saturated precursor solution;

[0013] 2) Cooling the saturated precursor solution in step 1) to room temperature and leaving it for a period of time to obtain the Cu(I)-based metal halide scintillator.

[0014] In some embodiments, in step 1), cis-2,6-dimethylmorpholine C6H 13 The molar ratio of NO to CuI is 1:1 to 4:1, preferably 3:1; and / or, in step 1), the solvent is a mixed solvent comprising CH3CN, H3PO2 and HI, preferably the volume ratio of CH3CN, H3PO2 and HI is 5:1:0.05;

[0015] And / or, in step 2), the standing time is 24 to 96 hours, preferably 48 hours.

[0016] In some embodiments, the method for preparing the above-mentioned Cu(I)-based metal halide scintillator comprises the following steps:

[0017] 1) 2.6 mmol cis-2,6-dimethylmorpholine C6H 13 NO and 0.86 mmol CuI were dissolved in a mixed solvent including 5 mL CH3CN, 1 mL H3PO2, and 0.05 mL HI at 75 °C to form a transparent saturated precursor solution;

[0018] 2) Slowly cooling the saturated precursor solution in step 1) to room temperature and leaving it for 48 hours to obtain the Cu(I)-based metal halide scintillator.

[0019] In a third aspect, the present invention provides the use of the above-mentioned Cu(I)-based metal halide scintillator in the preparation of X-ray scintillator materials, such as X-ray scintillator films.

[0020] In a fourth aspect, the present invention provides applications of the above-mentioned Cu(I)-based metal halide scintillator in the field of X-ray imaging, such as medical image detection or industrial detection.

[0021] Beneficial Effects

[0022] The present invention provides a Cu(I)-based metal halide scintillator for X-ray scintillation imaging. Compared with the prior art, the present invention has the following advantages:

[0023] 1. The present invention uses cuprous iodide, which is abundant on earth, cheap and low in toxicity, as raw material, does not contain precious metals or rare earth metal elements, and reduces production costs. The entire preparation process is mild, does not involve highly toxic and highly polluting organic reagents, etc., and is simple to operate and environmentally friendly.

[0024] 2. The present invention (CISDM) 4[Cu4I8]·2H2O has good scintillation performance, and the light yield is measured to be 41,042 photon MeV -1 The detection limit was determined to be 86.8 nGy s -1 , which is lower than the minimum dose rate required for X-ray medical diagnosis (5.5 μGyair s -1 ) is 63 times lower. In addition, the present invention evaluates its stability to high-energy rays. The (CISDM)4[Cu4I8]·2H2O scintillator is 133.64μGy s -1 After continuous irradiation for 1 hour under strong X-rays with a dose rate of 1.5 %, the change of RL intensity can be ignored, showing good stability.

[0025] 3. The present invention can achieve high-resolution X-ray imaging, with a spatial resolution of up to 108lp mm due to its high optical transparency and low scattering. -1 , representing the latest state of the art in metal halide based scintillators. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is the crystal structure diagram of (CISDM)4[Cu4I8]·2H2O metal halide scintillator.

[0027] Figure 2 These are the SCXRD patterns (simulated) and PXRD patterns (experimental) of (CISDM)4[Cu4I8]·2H2O metal halide scintillator.

[0028] Figure 3 This is the PXRD pattern of (CISDM)4[Cu4I8]·2H2O metal halide scintillator.

[0029] Figure 4This is a comparison chart of the x-ray radiation luminescence spectrum RL and photoluminescence spectrum PL of (CISDM)4[Cu4I8]·2H2O metal halide scintillator.

[0030] Figure 5 The linear curve of the X-ray radiation intensity of (CISDM)4[Cu4I8]·2H2O and CsI:Tl versus the X-ray dose rate in a large range.

[0031] Figure 6 This is the stability cycle diagram of (CISDM)4[Cu4I8]·2H2O under strong X-ray dose radiation for 1 hour.

[0032] Figure 7 Imaging of (CISDM)4[Cu4I8]·2H2O under X-ray irradiation.

[0033] Figure 8 is the modulation transfer function (MTF) of the (CISDM)4[Cu4I8]·2H2O oblique edge image. DETAILED DESCRIPTION

[0034] The technical scheme of the present invention will be further described in detail below in conjunction with specific embodiments. It should be understood that the following embodiments are only exemplary descriptions and explanations of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are included in the scope that the present invention is intended to protect.

[0035] Unless otherwise specified, the raw materials and reagents used in the following examples are commercially available or can be prepared by known methods.

[0036] Example 1 Synthesis of (CISDM)4[Cu4I8]·2H2O

[0037] C6H 13 NO (cis-2,6-dimethylmorpholine, 2.6mmol, 300mg) and CuI (0.86mmol, 165mg) (molar ratio, 3:1) were dissolved in a mixed solvent of 5mL CH3CN, 1mL H3PO2 and 0.05mL HI at 75°C to form a transparent saturated precursor solution. The solution was slowly cooled to room temperature and left for 48 hours to obtain colorless and transparent flake crystals (CISDM) 4[Cu4I8]·2H2O. CISDM represents C6H 13 NO, cis-2,6-dimethylmorpholine.

[0038] The crystal structure of (CISDM)4[Cu4I8]·2H2O is as follows Figure 1 The unit cell parameters are shown in Table 1.

[0039] Table 1 Crystallographic parameters of (CISDM) 4[Cu4I8]·2H2O

[0040]

[0041]

[0042] Example 2 Experimental Analysis

[0043] The crystal obtained in Example 1 was tested using a Bruker D8 Advance single crystal X-ray diffractometer. The diffraction light source was CrystalClear software package was used for data reduction and empirical absorption correction, and SHELXL-97 program was used for structural analysis and refinement to obtain the crystal structure. XRD test of crystal powder was carried out using Rigaku Miniflex 600 X-ray powder diffractometer, and the radiation source was Cu target Ka radiation. The scanning range was 5-40° and the scanning rate was 5° / min.

[0044] The photoluminescence spectra of the crystals were measured at room temperature using a FLS1000 Edinburgh fluorescence spectrometer. The corresponding RL spectra were measured by a FLS920 spectrofluorimeter equipped with an X-ray tube. The FLS 920 spectrofluorimeter (Edinburgh Instruments Ltd., UK) was equipped with an X-ray tube (TUB00154-9I-W06, Mo target, tube voltage 70 kV) to measure the RL spectra.

[0045] The corresponding RL intensity can be calculated by integrating the RL spectrum. The corresponding photon counting result is obtained by integrating the RL spectrum, and the specific light yield value can be calculated by slope comparison.

[0046] The stability cycle diagram obtained under X-ray dose irradiation for 1 hour was measured by a FLS920 spectrofluorimeter equipped with an X-ray tube (TUB00154-9I-W06, Mo target, tube voltage of 70 kV).

[0047] The X-ray images were obtained by connecting an inverted fluorescence microscope to a portable X-ray tube, with a 200-mesh copper mesh as the imaging object.

[0048] The modulation transfer function (MTF) is defined as the transfer capability of the input signal modulated spatial frequency, which is usually used as an evaluation index of the spatial resolution performance of the imaging system. MTF is defined as the contrast of the output image / the contrast of the input image. Since the contrast of the output image is always less than the contrast of the input image, the MTF value is between 0 and 1. When the MTF value drops to 0.2, the spatial resolution can be determined by the corresponding spatial frequency. Here, the slant edge method is used to calculate the MTF curve. An X-ray image is taken using an aluminum (Al) sheet with a sharp edge, and the edge spread function (ESF) can be obtained from the slant edge profile of the X-ray image. MTF can be calculated by the following formula (S1).

[0049]

[0050] Where ν is the spatial frequency, x is the position of the pixel, the line spread function (LSF) is the derivative of the ESF, and the MTF is the Fourier transform of the LSF. The MTF of the image is then calculated using Image J (https: / / imagej.en.softonic.com / ) software.

[0051] Figure 2 Figure 2 shows the PXRD pattern of (CISDM)4[Cu4I8]·2H2O metal halide scintillator and the simulated PXRD pattern with the single crystal result. The PXRD pattern of (CISDM)4[Cu4I8]·2H2O is in good agreement with the simulated pattern of SCXRD data, confirming the high phase purity of the prepared two-dimensional metal halide. Figure 3 This is the PXRD pattern of (CISDM)4[Cu4I8]·2H2O metal halide scintillator.

[0052] Figure 4 This is a comparison chart of the x-ray radiation luminescence spectrum and photoluminescence spectrum of (CISDM)4[Cu4I8]·2H2O metal halide. Figure 4 showed that the same radiative recombination pathway occurs under X-ray and UV excitation.

[0053] Figure 5 The linear curves of the X-ray radiation intensity of (CISDM)4[Cu4I8]·2H2O and CsI:Tl over a wide range of X-ray dose rates are shown in Figure 2. The light yield and detection limit of (CISDM)4[Cu4I8]·2H2O can be obtained by calculation and analysis. Figure 5It can be seen that the corresponding photon counting results are obtained by integrating the RL spectrum. The light yield is defined as the ratio of the number of photons emitted from the luminous point to the total absorbed X-ray energy, which represents the internal X-ray conversion efficiency. Therefore, the number of emitted photons of the scintillator should be normalized to the same X-ray attenuation. In addition, the reaction of CsI:Tl is >1.31 times higher than that of (CISDM)4[Cu4I8]·2H2O. Based on this, the calculated light yield of the (CISDM)4[Cu4I8]·2H2O scintillator is 41,042photon MeV -1 The detection limit was determined to be 86.8 nGy s -1 .

[0054] Figure 6 This is the stability cycle diagram of (CISDM)4[Cu4I8]·2H2O under strong X-ray dose radiation for 1 hour, which means good stability.

[0055] Figure 7 (CISDM)4[Cu4I8]·2H2O was imaged under X-ray irradiation, indicating that it has good imaging ability.

[0056] Figure 8 is the modulation transfer function (MTF) of the (CISDM)4[Cu4I8]·2H2O oblique edge image. By calculation, the specific spatial resolution value of X-ray imaging can be obtained. Figure 8 It can be seen that when MTF = 0.2, the spatial resolution of X-ray imaging is 108lp mm -1 .

[0057] The above is an explanation of the embodiments of the present invention. However, the present invention is not limited to the above embodiments. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A Cu(I)-based metal halide scintillator having a structural formula of (CISDM)4[Cu4I8]·2H2O; CISDM stands for cis-2,6-dimethylmorpholine, with the molecular formula C6H 13 NO.

2. The Cu(I)-based metal halide scintillator according to claim 1, characterized in that: The Cu(I)-based metal halide scintillator is a colorless and transparent flaky crystal; And / or, the PXRD spectrum of the Cu(I)-based metal halide scintillator is shown in FIG3 ; And / or, the crystallographic parameters of the Cu(I)-based metal halide scintillator are shown in the following table:

3. The method for preparing the Cu(I)-based metal halide scintillator according to claim 1 or 2, comprising the following steps: 1) Resuspend cis-2,6-dimethylmorpholine C6H 13 NO and CuI are dissolved in a solvent to form a transparent saturated precursor solution; the solvent is a mixed solvent including CH3CN, H3PO2 and HI; 2) Cooling the saturated precursor solution in step 1) to room temperature and leaving it for a period of time to obtain the Cu(I)-based metal halide scintillator.

4. The preparation method according to claim 3, characterized in that: In step 1), cis-2,6-dimethylmorpholine C6H 13 The molar ratio of NO to CuI is 1:1 to 4:1; And / or, in step 1), the volume ratio of CH3CN, H3PO2 and HI is 5:1:0.05; And / or, in step 2), the standing time is 24 to 96 hours.

5. The preparation method according to claim 4, characterized in that: In step 1), cis-2,6-dimethylmorpholine C6H 13 The molar ratio of NO and CuI is 3:1; And / or, in step 2), the standing time is 48 hours.

6. The preparation method according to claim 3 or 4, characterized in that: The preparation method of the Cu(I)-based metal halide scintillator comprises the following steps: 1) 2.6 mmol cis-2,6-dimethylmorpholine C6H 13 NO and 0.86 mmol CuI were dissolved in a mixed solvent including 5 mL CH3CN, 1 mL H3PO2, and 0.05 mL HI at 75 °C to form a transparent saturated precursor solution; 2) Slowly cooling the saturated precursor solution in step 1) to room temperature and leaving it for 48 hours to obtain the Cu(I)-based metal halide scintillator.

7. Use of the Cu(I)-based metal halide scintillator according to claim 1 or 2 in the preparation of X-ray scintillator materials.

8. The use according to claim 7, characterized in that: The X-ray scintillator material is an X-ray scintillator film.

9. Use of the Cu(I)-based metal halide scintillator according to claim 1 or 2 in the field of X-ray imaging.

10. The use according to claim 9, characterized in that: The field of X-ray imaging is the field of medical image detection or industrial detection.

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