Gamma detector array preparation method based on single crystal material

Abstract

The invention discloses a preparation method of a gamma detector array based on a single crystal material, and relates to the technical field of gamma detection. The invention provides a preparation method of a perovskite single crystal material. The preparation method comprises the following steps: mixing methyl ammonium bromide powder and lead bromide powder, and dissolving in an N, N-dimethylformamide solvent to obtain an MAPbBr3 precursor solution; the preparation method comprises the following steps: dissolving formamidine chloride in an N, N-dimethylformamide solvent to obtain an FACl precursor solution; taking the FACl precursor solution, adding the MAPbBr3 precursor solution, mixing and clarifying to obtain an MAPbBr3-FACl solution; and filtering the MAPbBr3-FACl solution solvent, volatilizing and baking to obtain the perovskite single crystal material. The invention further provides a gamma ray detector array based on the perovskite single crystal material and a preparation method of the gamma ray detector array. The gamma ray detector array comprises the perovskite single crystal material, a low-power function metal layer and a high-power function metal layer, wherein the low-power function metal layer and the high-power function metal layer are deposited on the two faces of the perovskite single crystal material respectively.

Description

Technical Field

[0001] The present invention relates to the field of gamma detection technology, and in particular to a perovskite single crystal material and a preparation method thereof, a gamma ray detector array and a preparation method thereof. Background Art

[0002] Gamma rays refer to photons with a wavelength less than 0.01nm. They have strong penetrating power and have been widely used in military and civilian fields, including medical treatment, material monitoring, radiation safety, etc. When gamma rays interact with electrons in atoms to ionize materials, relevant information about the object being measured can be obtained by detecting changes in the intensity, direction, phase and energy of gamma ray photons.

[0003] The main detection principles of gamma detection technology are divided into indirect detection and direct detection. Indirect detection first uses a scintillator to convert gamma-ray signals into visible light signals, and then uses a visible light complementary metal oxide semiconductor or charge-coupled device for detection and imaging. Compared with indirect detection technology, direct detection technology can directly convert gamma-ray photons into electron-hole pairs, avoiding the intermediate conversion process of visible light photons, and has greater advantages in quantum efficiency and energy resolution.

[0004] However, direct detection technology places higher demands on the optoelectronic properties of detection materials. Currently, gamma-ray detectors based on direct detection mechanisms all have certain problems. For example, although gamma-ray detectors based on high-purity germanium have high energy resolution, they require extremely low operating temperatures to reduce the dark current of the device; and gamma-ray detectors based on cadmium zinc telluride have extremely high preparation costs and are difficult to meet the current needs for low cost, high performance, and portability; in addition, most of the current detection technologies are based on a single detection device, which makes it difficult to extract the distribution information of more complex spatial signals. Summary of the invention

[0005] The purpose of the present invention is to solve the problem that the detection materials of the existing gamma-ray detector arrays are difficult to meet the current demand for low cost, high performance and portability. The present invention provides a perovskite single crystal material and a preparation method thereof, a gamma-ray detector array based on the material and a preparation method thereof, the detector array is prepared based on a solution method, has low cost, and has high detection performance under room temperature working conditions, and the arrayed preparation provides the ability of gamma-ray imaging.

[0006] In order to achieve the above-mentioned purpose, the present invention specifically adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a method for preparing a perovskite single crystal material, comprising the following steps:

[0008] S1, providing methyl ammonium bromide powder, lead bromide powder, and N,N-dimethylformamide solvent, mixing the methyl ammonium bromide powder and the lead bromide powder and dissolving them in N,N-dimethylformamide solvent to obtain a MAPbBr3 precursor solution;

[0009] S2, providing formamidine chloride and dissolving it in N,N-dimethylformamide solvent to obtain a FACl precursor solution;

[0010] S3, taking a certain amount of FACl precursor solution, adding MAPbBr3 precursor solution, mixing and clarifying to obtain MAPbBr3-FACl solution;

[0011] S4. After filtering the MAPbBr3-FACl solution, the solvent is evaporated and baked to obtain a perovskite single crystal material.

[0012] Furthermore, the weight ratio of methyl ammonium bromide powder to lead bromide powder in S1 is 1:3 to 2:3.

[0013] Furthermore, the amount of formamidine chloride added in S2 is 30 to 70 μmol.

[0014] Furthermore, the specific operation of S4 is to filter the MAPbBr3-FACl solution using a filter membrane, and dispense the solution into containers, place the containers in a constant temperature oven to evaporate the solvent, control the temperature of the constant temperature oven, and bake for a preset time.

[0015] Furthermore, the temperature of the constant temperature oven is 28-32° C., and the preset time is 7-9 days.

[0016] In a second aspect, the present invention provides a perovskite single crystal material prepared by the above-mentioned method for preparing a perovskite single crystal material, wherein the resistivity of the perovskite single crystal material is 2×10 8 ~7×10 8 Ωcm.

[0017] In a third aspect, the present invention also provides a gamma-ray detector array based on the above-mentioned perovskite single crystal material, wherein the array includes the above-mentioned perovskite single crystal material and metal layers deposited on two opposite sides of the perovskite single crystal material, one side is a low-power function metal layer, and the other side is a high-power function metal layer.

[0018] Fourthly, the present invention also provides a method for preparing a gamma-ray detector array based on the above, comprising the following steps:

[0019] S1, taking a perovskite single crystal material and pre-treating it to obtain a pre-treated perovskite single crystal material;

[0020] S2. Using a thermal evaporation process and an arrayed mask design, a low-power function metal layer and a high-power function metal layer are deposited on two opposite sides of the perovskite single crystal material to obtain a perovskite gamma-ray detector.

[0021] Furthermore, the pretreatment is to use sandpaper with different mesh densities to polish the surface of the single crystal material, and clean it to obtain a perovskite single crystal material with a smooth surface.

[0022] Furthermore, the low-power function metal layer and the high-power function metal layer are aluminum electrodes and gold electrodes respectively.

[0023] Compared with the prior art, the advantages of the present invention are:

[0024] 1. A method for preparing a perovskite single crystal material involved in the present invention uses a low-temperature solvent volatilization method to prepare a MAPbBr3-FACl perovskite single crystal material. By setting a low-temperature preparation environment, the temperature difference with the room temperature environment is small. When the crystal is taken out of the solution, internal stress will not be generated due to the large temperature difference, thereby avoiding the generation of cracks inside the crystal. In addition, by introducing FACl, the cation and anion defects inside and on the surface of the crystal can be effectively filled, thereby reducing the defect density and improving the photoelectric response characteristics. Therefore, the perovskite single crystal material prepared by the preparation method of the present invention has a higher resistivity and less defect density than the existing perovskite single crystal material, and has excellent performance and superiority.

[0025] 2. The perovskite single crystal material involved in the present invention has good material uniformity, high resistivity, low defect density and excellent performance.

[0026] 3. The gamma-ray detector array involved in the present invention can not only detect gamma-ray signals, but also perform imaging and obtain spatial distribution information.

[0027] 4. The present invention relates to a method for preparing a gamma-ray detector array. By pretreating the perovskite single crystal material and performing a fine polishing process, the surface of the perovskite single crystal material is made very smooth, thereby avoiding the problem of poor contact of the deposited electrodes due to surface unevenness, so that the prepared gamma-ray detector array has good performance and can not only detect gamma-ray signals, but also perform imaging and obtain spatial distribution information. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A schematic diagram of the structure of a gamma-ray detector array in an embodiment of the present invention Figure 1 .

[0029] Figure 2 A schematic diagram of the structure of a gamma-ray detector array in an embodiment of the present invention Figure 2 .

[0030] The left picture is a schematic diagram of the front electrode layout of the gamma-ray detector array, and the right picture is a schematic diagram of the back common electrode layout.

[0031] Figure 3 This is a diagram showing the X-ray diffractometer measurement results of the perovskite single crystal material 1 in Experimental Example 1 of the present invention.

[0032] Figure 4 This is a diagram showing the dark current and resistivity measurement results of the perovskite gamma-ray detector 1 in Experimental Example 2 of the present invention.

[0033] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0034] Therefore, the following detailed description of the embodiments of the present invention is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. DETAILED DESCRIPTION

[0035] In a first aspect, the present invention provides a method for preparing a perovskite single crystal material, comprising the following steps: S1, providing methyl ammonium bromide powder, lead bromide powder, and N,N-dimethylformamide solvent, mixing the methyl ammonium bromide powder and the lead bromide powder and dissolving them in the N,N-dimethylformamide solvent to obtain a MAPbBr3 precursor solution;

[0036] S2, providing formamidine chloride and dissolving it in N,N-dimethylformamide solvent to obtain a FACl precursor solution;

[0037] S3, taking a certain amount of FACl precursor solution, adding MAPbBr3 precursor solution, mixing and clarifying to obtain MAPbBr3-FACl solution;

[0038] S4. After filtering the MAPbBr3-FACl solution, the solvent is evaporated and baked to obtain a perovskite single crystal material.

[0039] It is understandable that the preparation method of a perovskite single crystal material of the present invention uses a low-temperature solvent volatilization method to prepare a MAPbBr3-FACl perovskite single crystal material. By setting a low-temperature preparation environment, the temperature difference with the room temperature environment is small. When the crystal is taken out of the solution, internal stress will not be generated due to the large temperature difference, thereby avoiding the generation of cracks inside the crystal. In addition, by introducing FACl, the cation and anion defects inside and on the surface of the crystal can be effectively filled, thereby reducing the defect density and improving the photoelectric response characteristics. Therefore, the prepared perovskite single crystal material has a higher resistivity and less defect density than the existing perovskite single crystal material, and has excellent performance and superiority.

[0040] In certain embodiments of the present invention, the weight ratio of methyl ammonium bromide powder to lead bromide powder in S1 is 1:3 to 2:3.

[0041] In certain embodiments of the present invention, the amount of formamidine chloride added in S2 is 30-70 μmol.

[0042] In certain embodiments of the present invention, the specific operation of S4 is to filter the MAPbBr3-FACl solution using a filter membrane, and dispense the solution into containers, place the containers in a constant temperature oven to evaporate the solvent, control the temperature of the constant temperature oven, and bake for a preset time.

[0043] In certain embodiments of the present invention, the temperature of the constant temperature oven is 28-32° C., and the preset time is 7-9 days.

[0044] In a second aspect, the present invention provides a perovskite single crystal material prepared by the above-mentioned method for preparing a perovskite single crystal material, wherein the resistivity of the perovskite single crystal material is 2×10 8 ~7×10 8 Ωcm. The material has good uniformity, high resistivity, low defect density and excellent performance.

[0045] In a third aspect, the present invention also provides a gamma-ray detector array based on the above-mentioned perovskite single crystal material, the array comprising the above-mentioned perovskite single crystal material and metal layers respectively deposited on two opposite sides of the perovskite single crystal material, one side being a low-power function metal layer and the other side being a high-power function metal layer. It can be understood that the gamma-ray detector array of the present invention can not only detect gamma-ray signals, but also perform imaging and obtain spatial distribution information.

[0046] In a fourth aspect, the present invention further provides a method for preparing a gamma-ray detector array based on the above, comprising the following steps:

[0047] S1, taking a perovskite single crystal material and pre-treating it to obtain a pre-treated perovskite single crystal material;

[0048] S2. Using a thermal evaporation process and an arrayed mask design, a low-power function metal layer and a high-power function metal layer are deposited on two opposite sides of the perovskite single crystal material to obtain a perovskite gamma-ray detector.

[0049] It can be understood that the preparation method of the gamma-ray detector array of the present invention makes the surface of the perovskite single crystal material very smooth by pre-treating the perovskite single crystal material and a fine polishing process, thereby avoiding the problem of poor contact of the deposited electrode due to surface unevenness, so that the prepared gamma-ray detector array has good performance and can not only detect gamma-ray signals, but also perform imaging and obtain spatial distribution information.

[0050] In certain embodiments of the present invention, the pretreatment is to polish the surface of the single crystal material using sandpaper with different mesh densities, and then clean it to obtain a perovskite single crystal material with a smooth surface.

[0051] In some embodiments of the present invention, the low-power function metal layer and the high-power function metal layer are respectively an aluminum electrode and a gold electrode.

[0052] Example 1

[0053] In this embodiment, the specific operations are:

[0054] (1) Weigh 1679.55 mg of methylammonium bromide (MABr) powder and 5505.15 mg of lead bromide (PbBr2) powder respectively, with a weighing error of less than 0.02%;

[0055] (2) Mix the weighed MABr and PbBr2 powders and dissolve them in 10 mL of N,N-dimethylformamide (DMF) solvent;

[0056] (3) fully stirring the above solution until the solution becomes clear to form a MAPbBr3 precursor solution;

[0057] (4) Weigh 402.6 mg of formamidinium chloride (FACl), dissolve it in 5 mL of DMF solvent, and mix thoroughly until the solution becomes clear to form a FACl precursor solution;

[0058] (5) adding a certain amount of FACl precursor solution to the MAPbBr3 precursor solution and mixing thoroughly until the solution becomes clear to form a MAPbBr3-FACl solution;

[0059] (6) filtering the MAPbBr3-FACl solution using a polytetrafluoroethylene filter membrane with a pore size of 0.22 μm and dispensing the solution into a flat-bottomed open glass container;

[0060] (7) placing the open glass container containing the MAPbBr3-FACl solution in a constant temperature oven, and partially covering the container opening with a glass sheet to maintain a low solvent evaporation rate;

[0061] (8) The temperature of the constant temperature oven was set to 30° C. and the baking was carried out for 8 days; and a bulk MAPbBr3-FACl perovskite single crystal material 1 was obtained.

[0062] Example 2

[0063] In this embodiment, the MAPbBr3-FACl perovskite single crystal material 1 prepared in Example 1 is taken and gently wiped with a dust-free cloth to keep it dry; the surface of the single crystal material is polished using sandpaper with different grid densities and cleaned to obtain a perovskite single crystal material with a smooth surface; based on a thermal evaporation process, an arrayed mask design is used to perform metal deposition on the front and back surfaces of the single crystal material to prepare a perovskite gamma-ray detector 1, see Figure 2 .

[0064] Experimental Example 1 Performance Characterization of the Perovskite Single Crystal Material 1 Prepared in Example 1

[0065] 1.1 Test operation

[0066] The crystal quality of the perovskite single crystal material 1 prepared in Example 1 was tested using an X-ray diffractometer (XRD). The test results are shown in Figure 3 .

[0067] 1.2 Results Analysis

[0068] See also Figure 3 It can be seen (the vertical axis is intensity, and the horizontal axis is 2Theta, which represents the angle) that the half-peak widths of the (100) and (200) crystal planes of the perovskite single crystal material are 0.088° and 0.155°, respectively. The material has good uniformity.

[0069] Experimental Example 2 Performance Characterization of the Perovskite Gamma-ray Detector 1 Prepared in Example 2 2.1 Experimental Operation

[0070] The dark current and resistivity of the perovskite gamma-ray detector 1 prepared in Example 2 were tested using a probe station system equipped with a Keithley 4200 original meter. The test results are shown in Figure 4 .

[0071] 2.2 Results Analysis

[0072] See also Figure 4 It can be seen that (the vertical axis is current, and the horizontal axis is voltage), the resistance of the perovskite gamma-ray detector 1 is 8.5×109 Ω, resistivity is 2.8×10 8 Ωcm.

[0073] In summary, according to the measurement of Test Example 1, the perovskite single crystal material of the present invention has good material uniformity and low defect density. According to the measurement of Test Example 2, the perovskite gamma-ray detector prepared using the perovskite single crystal material of the present invention has high resistivity. The perovskite single crystal material and the preparation method thereof, the gamma-ray detector array and the preparation method thereof of the present invention have advantages.

[0074] The above embodiment is only one implementation of the present invention, and its description is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be based on the attached claims.

Claims

1. A method for preparing a perovskite single crystal material, characterized in that: The following steps are involved: S1, providing methyl ammonium bromide powder, lead bromide powder, and N,N-dimethylformamide solvent, mixing the methyl ammonium bromide powder and the lead bromide powder and dissolving them in N,N-dimethylformamide solvent to obtain a MAPbBr3 precursor solution; S2, providing formamidine chloride and dissolving it in N,N-dimethylformamide solvent to obtain a FACl precursor solution; S3, taking a certain amount of FACl precursor solution, adding MAPbBr3 precursor solution, mixing and clarifying to obtain MAPbBr3-FACl solution; S4. After filtering the MAPbBr3-FACl solution, the solvent is evaporated and baked to obtain a perovskite single crystal material.

2. The method for preparing a perovskite single crystal material according to claim 1, characterized in that: The weight ratio of methyl ammonium bromide powder to lead bromide powder in S1 is 1:3 to 2:

3.

3. The method for preparing a perovskite single crystal material according to claim 2, characterized in that: The amount of formamidine chloride added in S2 is 30-70 μmol.

4. The method for preparing a perovskite single crystal material according to claim 1, characterized in that: The specific operation of S4 is to filter the MAPbBr3-FACl solution using a filter membrane, and pack it into containers, place the containers in a constant temperature oven to evaporate the solvent, control the temperature of the constant temperature oven, and bake for a preset time.

5. The method for preparing a perovskite single crystal material according to claim 4, characterized in that: The temperature of the constant temperature oven is 28-32° C., and the preset time is 7-9 days.

6. A perovskite single crystal material prepared by the preparation method according to any one of claims 1 to 5, characterized in that: The resistivity of the perovskite single crystal material is 2×10 8 ~7×10 8 Ωcm.

7. A gamma-ray detector array based on the perovskite single crystal material according to claim 6, characterized in that: The array includes the perovskite single crystal material as described in claim 6 and metal layers deposited on two opposite sides of the perovskite single crystal material, one side is a low-power function metal layer, and the other side is a high-power function metal layer.

8. A method for preparing a gamma-ray detector array according to claim 7, characterized in that: The following steps are involved: S1, taking a perovskite single crystal material and pre-treating it to obtain a pre-treated perovskite single crystal material; S2. Using a thermal evaporation process and an arrayed mask design, a low-power function metal layer and a high-power function metal layer are deposited on two opposite sides of the perovskite single crystal material to obtain a perovskite gamma-ray detector.

9. The method for preparing a gamma-ray detector array according to claim 8, characterized in that: The pretreatment is to use sandpaper with different mesh densities to polish the surface of the single crystal material, and then clean it to obtain a perovskite single crystal material with a smooth surface.

10. The method for preparing a gamma-ray detector array according to claim 8, characterized in that: The low-power function metal layer and the high-power function metal layer are respectively an aluminum electrode and a gold electrode.

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