Perovskite composite material and preparation method thereof, and nuclear radiation detector comprising perovskite composite material

Abstract

The invention provides a perovskite composite material for nuclear radiation detection, which is characterized in that the perovskite composite material comprises a 3D perovskite single crystal CsPbBr3-XIX, and the X is equal to 0.3-1; and a 0D perovskite single crystal Cs4PbBrYI6-Y on a portion of the surface of the 3D perovskite single crystal, where Y = 1-2.5, where the 0D perovskite single crystal and the 3D perovskite single crystal form a heterojunction structure. The perovskite composite material can be used for forming a nuclear radiation detector with high sensitivity and good stability.

Description

Technical Field

[0001] The present invention belongs to the technical field of nuclear radiation detection, and in particular relates to a perovskite composite material and a preparation method thereof, and a nuclear radiation detector comprising the same. Background Art

[0002] Currently, nuclear radiation detection technology is increasingly being used in many fields such as nuclear energy industry, medicine, military, space technology, etc. Accordingly, the demand for cost-effective and high-performance nuclear radiation detectors is also increasing.

[0003] Nuclear radiation detectors based on semiconductors have been widely used. After being exposed to nuclear radiation, semiconductors generate electrical signals due to the photoelectric effect. By monitoring this electrical signal, nuclear radiation can be detected.

[0004] Perovskite materials are a new class of semiconductor materials that have been used in solar cells and other applications. They have high photoelectric responsiveness and low cost, so they also have good prospects for nuclear radiation detection. However, to date, high-performance nuclear radiation detectors based on perovskite semiconductors have not yet been obtained.

[0005] There is a need for the development of high-performance perovskite semiconductor-based nuclear radiation detectors. Summary of the invention

[0006] In one aspect, the present invention provides a perovskite composite material for nuclear radiation detection, characterized in that the perovskite composite material comprises:

[0007] 3D perovskite single crystal CsPbBr 3-X I X , where X = 0.3~1; and

[0008] 0D perovskite single crystal Cs4PbBr on a partial surface of the 3D perovskite single crystal Y I 6-Y , where Y = 1 ~ 2.5,

[0009] The 0D perovskite single crystal and the 3D perovskite single crystal form a heterojunction structure.

[0010] Preferably, the 0D perovskite single crystal forms a single crystal layer that completely covers one crystal plane of the 3D perovskite single crystal.

[0011] In another aspect, the present invention provides a method for preparing a perovskite composite material, characterized in that the method comprises the following steps:

[0012] (1) Growth of 3D perovskite single crystal CsPbBr 3-X I X, where X = 0.3~1;

[0013] (2) fixing the 3D perovskite single crystal in step (1) on a substrate using microcrystalline wax and using the microcrystalline wax as a mask to expose a portion of the surface of the 3D perovskite single crystal;

[0014] (3) placing the 3D perovskite single crystal and the substrate in step (2) into a 0D perovskite precursor solution and heating at a temperature lower than the melting temperature of the microcrystalline wax to grow a 0D perovskite single crystal on the surface of the portion of the 3D perovskite single crystal to form a heterojunction structure, thereby obtaining a perovskite composite material on the substrate, wherein the 0D perovskite single crystal is Cs4PbBr Y I 6-Y , where Y = 1~2.5;

[0015] (4) The perovskite composite material on the substrate in step (3) is taken out from the 0D perovskite precursor solution, and heated to a temperature above the melting temperature of the microcrystalline wax to melt the microcrystalline wax, so as to separate the perovskite composite material from the substrate.

[0016] Preferably, in step (1), the 3D perovskite single crystal is prepared by heating a 3D perovskite precursor solution at 60-100° C., wherein the 3D perovskite precursor solution is a solution of bromide and iodide salts of Cs and Pb.

[0017] Preferably, the 0D perovskite precursor solution in step (3) is a solution of bromide and iodide salts of Cs and Pb.

[0018] Preferably, the concentration of the precursor in the 3D perovskite precursor solution in step (1) or the 0D perovskite precursor solution in step (3) is 0.8-1.2 mol / L, and the solvent used is a mixed solvent of dimethyl sulfoxide (DMSO) and N,N-dimethylformamide (DMF), and the volume ratio of the two solvents is DMSO:DMF=1:1-1:4.

[0019] Preferably, the substrate is a quartz wafer or a silicon wafer.

[0020] Preferably, the melting temperature of the microcrystalline wax is 87-92°C.

[0021] In yet another aspect, the present invention provides a nuclear radiation detector, characterized in that the nuclear radiation detector comprises:

[0022] The above-mentioned perovskite composite material or the perovskite composite material prepared according to the above-mentioned method; and

[0023] Detector electrodes electrically connected to the 3D perovskite single crystal and the 0D perovskite single crystal in the heterojunction structure in the perovskite composite material, respectively. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Schematic diagram of a growth process of a perovskite composite material according to one embodiment of the present invention.

[0025] Figure 2 Surface morphology of the perovskite composite material of Example 1 of the present invention

[0026] Figure 3 This is a cross-sectional SEM image of the perovskite composite material of Example 1 of the present invention. DETAILED DESCRIPTION

[0027] In recent years, perovskite materials have been shown to be used to make devices such as light-emitting diodes, lasers, solar cells, and radiation detectors, showing great application potential. However, without relying on any theory, the inventors found that the basic form of perovskite materials used in optoelectronic devices, 3D (three-dimensional) perovskites, are prone to polarization, resulting in ion migration, which affects their ability to generate electrons under radiation, resulting in poor stability when detecting nuclear radiation.

[0028] In addition to 3D perovskites, there are other forms of perovskites, including low-dimensional perovskites, such as 0D (zero-dimensional), quasi-2D (quasi-two-dimensional), and 2D (two-dimensional) perovskites. The dimensionality of a perovskite depends on the atomic arrangement inside its crystal. For example, a three-dimensional perovskite refers to a perovskite in which the octahedra in its perovskite lattice are connected to each other through shared atoms to form a three-dimensional spatial network. Its general chemical formula can be ABX3, where the X atoms at the vertices of the octahedrons are shared by adjacent octahedra to connect the octahedra to each other. In contrast, a zero-dimensional perovskite refers to a perovskite in which the octahedra in its perovskite lattice are separated from each other and can be regarded as isolated octahedral "points" (i.e., zero dimensions). Its general chemical formula can be A4BX6, where the X atoms are not shared by adjacent octahedra.

[0029] The inventors found that 0D perovskite in low-dimensional perovskite can effectively inhibit ion migration, for example, it has high stability for X-ray detection. However, the detection sensitivity of 0D perovskite devices is much lower than that of 3D perovskite devices, with a difference of about two orders of magnitude. Although it can be used for X-ray detection, for nuclear radiation detection, sensitivity is one of the important indicators to measure the performance of detection devices, which makes 0D perovskite difficult to use for nuclear radiation detection.

[0030] The inventors unexpectedly discovered that by using a heterojunction structure composed of a 3D perovskite single crystal of a Cs-Pb-Br-I series material and a 0D perovskite single crystal also of a Cs-Pb-Br-I series material, the above-mentioned shortcomings of the above-mentioned 3D perovskite and 0D perovskite can be overcome to obtain a composite material suitable for nuclear radiation detection.

[0031] In one aspect, the present invention provides a perovskite composite material for nuclear radiation detection, characterized in that the perovskite composite material comprises:

[0032] 3D perovskite single crystal CsPbBr 3-X I X , where X = 0.3~1; and

[0033] 0D perovskite single crystal Cs4PbBr on a partial surface of the 3D perovskite single crystal Y I 6-Y , where Y = 1 ~ 2.5,

[0034] The 0D perovskite single crystal and the 3D perovskite single crystal form a heterojunction structure.

[0035] The perovskite composite material comprises a heterojunction structure formed by 3D perovskite and 0D perovskite in contact with each other. As mentioned above, 3D perovskite and 0D perovskite are materials with different atomic arrangements. The 3D perovskite single crystal is specifically CsPbBr 3-X I X , where X = 0.3~1. 0D perovskite single crystal is specifically Cs4PbBr Y I 6-Y , where Y=1~2.5. Although these two Cs-Pb-Br-I series materials have a high degree of similarity due to the same octahedron in the lattice, they are not the same material because of the different specific atomic arrangements. They contact each other to form a semiconductor heterojunction structure, and therefore have the beneficial properties of the heterojunction structure. The semiconductor heterojunction structure is a special PN junction that can effectively stabilize the lattice and increase the resistivity of the material. When used in optoelectronic devices, it can inhibit ion migration or reduce the dark current of the device. In addition, the built-in electric field formed by the potential difference on both sides of the heterojunction structure can also be used to separate carriers and collect them.

[0036] The similarity of the two materials increases the cohesion of the heterojunction structure and improves its stability, such as mechanical stability and thermal stability.

[0037] When the perovskite composite material is used for nuclear radiation detection, the 3D perovskite single crystal with high detection sensitivity undergoes a photoelectric effect under nuclear radiation, generating an electrical signal related to the radiation intensity. On part of the surface of the 3D perovskite single crystal, a 0D perovskite single crystal is formed, which can effectively inhibit the ion migration of the 3D perovskite and greatly improve the detection stability of the 3D perovskite single crystal.

[0038] X and Y both change within a certain range. When X and Y change, the performance of the heterojunction structure will also change accordingly.

[0039] The 0D perovskite single crystal covers part of the surface of the 3D perovskite single crystal. If the entire surface of the 3D perovskite single crystal is covered by the 0D perovskite single crystal, the 3D perovskite single crystal cannot be connected to an external circuit to form a detection device.

[0040] Preferably, the 0D perovskite single crystal forms a single crystal layer that completely covers one crystal plane of the 3D perovskite single crystal. At this time, the 0D perovskite exists in the form of one or more layers of single crystal particles. The orientations of these single crystal particles can be the same or different, and can be stacked in a direction perpendicular to the surface. The complete layered 0D perovskite single crystal is structurally advantageous for preparing heterojunction structure devices.

[0041] In another aspect, the present invention provides a method for preparing a perovskite composite material, characterized in that the method comprises the following steps:

[0042] (1) Growth of 3D perovskite single crystal CsPbBr 3-X I X , where X = 0.3~1;

[0043] (2) fixing the 3D perovskite single crystal in step (1) on a substrate using microcrystalline wax and using the microcrystalline wax as a mask to expose a portion of the surface of the 3D perovskite single crystal;

[0044] (3) placing the 3D perovskite single crystal and the substrate in step (2) into a 0D perovskite precursor solution and heating at a temperature lower than the melting temperature of the microcrystalline wax to grow a 0D perovskite single crystal on the surface of the portion of the 3D perovskite single crystal to form a heterojunction structure, thereby obtaining a perovskite composite material on the substrate, wherein the 0D perovskite single crystal is Cs4PbBr Y I 6-Y , where Y = 1~2.5;

[0045] (4) The perovskite composite material on the substrate in step (3) is taken out from the 0D perovskite precursor solution, and heated to a temperature above the melting temperature of the microcrystalline wax to melt the microcrystalline wax, so as to separate the perovskite composite material from the substrate.

[0046] By sequentially performing the above steps, 3D perovskite single crystal CsPbBr 3-X I X A layer of 0D perovskite single crystal Cs4PbBr is grown on a specific surface Y I 6-Y A heterojunction structure is formed, and the resulting perovskite composite can be easily separated. Figure 1 Schematic diagram of a growth process of a perovskite composite material according to one embodiment of the present invention.

[0047] In step (1), a 3D perovskite single crystal portion in a heterojunction structure is formed for subsequent heterojunction structure preparation.

[0048] In one embodiment, in step (1), the 3D perovskite single crystal is prepared by heating a 3D perovskite precursor solution at 60-100° C., wherein the 3D perovskite precursor solution is a solution of bromide and iodide salts of Cs and Pb. The solvent may be any solvent compatible with the method of the present invention, but is particularly preferably an organic solvent because of its higher volatility. The solution may be a solution formed by dissolving bromide and iodide salts of Cs and Pb, wherein the molar ratio of Cs ions, Pb ions, Br ions and I ions conforms to the chemical formula of the 3D perovskite single crystal. That is, the molar ratio of Cs ions, Pb ions, Br ions and I ions is 1:1:3-X:X. The bromide and iodide salts of Cs and Pb include CsBr, CsI, PbBr2 and PbI2. The combination of these bromide and iodide salts may be freely selected according to the desired molar ratio. When the precursor solution is heated, water evaporates, solutes precipitate and grow into 3D perovskite single crystals.

[0049] In step (2), the 3D perovskite single crystal is fixed on the substrate for subsequent operation. The fixation is performed by using microcrystalline wax. The microcrystalline wax material has a suitable melting temperature, suitable adhesion and good formability, and is particularly insoluble in polar solvents constituting the precursor, and is easy to peel off from the crystal surface, so it is particularly suitable for the method of the present invention. In the method of the present invention, the microcrystalline wax is not only used to fix the 3D perovskite single crystal, but also acts as a temporary mask to cover the surface where a layer of 0D perovskite single crystal is not desired to be formed.

[0050] Preferably, the substrate is a quartz wafer or a silicon wafer, which are cheap, flat and have good bonding performance with microcrystalline wax, and are convenient to be used as the substrate of the method of the present invention.

[0051] In one embodiment, the 0D perovskite precursor solution in step (3) is a solution of bromine and iodine salts of Cs and Pb. The solution can be a solution formed by dissolving bromine and iodine salts of Cs and Pb, wherein the molar ratio of Cs ions, Pb ions, Br ions and I ions conforms to the chemical formula of the 0D perovskite single crystal. That is, the molar ratio of Cs ions, Pb ions, Br ions and I ions is 4: 1: Y: 6-Y. Similarly, bromine and iodine salts of Cs and Pb include CsBr, CsI, PbBr2 and PbI2. The combination of these bromine and iodine salts can be freely selected according to the desired molar ratio. When the precursor solution is heated, water evaporates, solutes precipitate and grow into 0D perovskite single crystals.

[0052] In one embodiment, the concentration of the 3D perovskite precursor solution in step (1) or the 0D perovskite precursor solution in step (3) is 0.8-1.2 mol / L, and the solvent used is a mixed solvent of dimethyl sulfoxide (DMSO) and N,N-dimethylformamide (DMF), and the volume ratio of the two solvents is DMSO:DMF=1:1-1:4. The solution concentration is based on the molar amount of the single crystal chemical formula. This combination of concentration and solvent can achieve the best balance between rapid evaporation of the solution and intact growth of the crystal.

[0053] In one embodiment, the melting temperature of the microcrystalline wax is 87-92° C. This melting temperature is preferred because the microcrystalline wax melts moderately when processed at this melting temperature and does not adversely affect the formed perovskite composite material when melted.

[0054] By changing the X and Y values ​​in the two precursor solutions, the performance of the heterojunction structure can be regulated to a certain extent. For example, the lattice constants of the two single crystals can be regulated.

[0055] In yet another aspect, the present invention provides a nuclear radiation detector, characterized in that the nuclear radiation detector comprises:

[0056] The aforementioned composite material or the perovskite composite material obtained by the aforementioned method; and

[0057] Detector electrodes electrically connected to the 3D perovskite single crystal and the 0D perovskite single crystal in the heterojunction structure in the perovskite composite material, respectively.

[0058] The perovskite composite material of the present invention can provide a highly sensitive and stable nuclear radiation detection performance as a core device of a nuclear radiation detector. The following step (5) can be performed after the above step (4): electrodes are formed on the surfaces of the 3D perovskite single crystal and the 0D perovskite single crystal in the heterojunction structure of the perovskite composite material formed in step (4). After electrodes are formed on the surfaces of the 3D perovskite single crystal and the 0D perovskite single crystal, respectively, the perovskite composite material can be used as a core device of a nuclear radiation detector. The formation method is preferably evaporation because it has little effect on the body of the perovskite composite material. The electrode material can be a conventional detector electrode, such as gold.

[0059] The present invention is described in detail below in conjunction with specific embodiments and drawings.

[0060] Example 1

[0061] Preparation of perovskite composites for nuclear radiation detection, including 3D perovskite CsPbBr 2.5 I 0.5 and 0D perovskite Cs4PbBr 2.5 I3.5 The heterojunction structure formed.

[0062] (1) 6.5 g of CsI, 5.33 g of CsBr, and 18.35 g of PbBr2 were dissolved in a mixed solution of 25 ml of DMSO and 25 ml of DMF and stirred at 55 °C for 12 h. The precursor concentration was 1 mol / L. The solution was then filtered through a PTFE filter with a pore size of 0.22 μm to obtain a 3D perovskite precursor solution. The solution was heated to 65 °C for crystal growth. After 3 to 5 days, CsPbBr was taken out. 2.5 I 0.5 Crystal.

[0063] (2) Use microcrystalline wax to treat CsPbBr 2.5 I 0.5 The crystals are masked to ensure that 0D perovskite crystals only grow on the exposed surface, and microcrystalline wax is used to fix the crystals to the silicon wafer.

[0064] (3) Dissolve 26.63g of CsBr, 19.5g of CsI, and 23.05g of PbI2 in a mixed solution of 25ml of DMSO and 25ml of DMF and stir at 55°C for 12h. The precursor concentration is 1mol / L. Then filter with a PTFE filter with a pore size of 0.22μm to obtain a 0D perovskite precursor solution. Place the 3D perovskite single crystal and substrate in step (2) and heat to 65°C for crystal growth for 3-5 days.

[0065] (4) The composite material and substrate grown in step (3) are removed from the precursor solution, heated to 90° C. to melt the microcrystalline wax, the composite material is removed from the substrate, and the crystal surface is rinsed with anhydrous ethanol, and finally dried.

[0066] Figure 2 This is a surface SEM image of the perovskite composite material of Example 1 of the present invention. As can be seen from the figure, a layer of 0D perovskite particles covers the surface of the 3D perovskite.

[0067] Figure 3 This is a cross-sectional SEM image of the perovskite composite material of Example 1 of the present invention. The upper left of the figure is a 3D single crystal, and the lower right is a 0D single crystal. It can be seen that the heterojunction structure interface between the two has good bonding.

[0068] The Au electrode was evaporated on the surface of the prepared perovskite composite material and used for nuclear radiation detection. The results showed that it had satisfactory sensitivity and detection stability. The perovskite composite material was also tested to have good mechanical stability and thermal stability.

[0069] Example 2

[0070] Perovskite composite materials for nuclear radiation detection are prepared, including a heterojunction structure formed by 3D perovskite CsPbBr2I1 and 0D perovskite Cs4PbBr2I4.

[0071] (1) Dissolve 10.4 g of CsI and 14.68 g of PbBr2 in a mixed solution of 25 ml of DMSO and 25 ml of DMF and stir at 55 °C for 12 h. The precursor concentration is 0.8 mol / L. Then filter with a PTFE filter with a pore size of 0.22 μm to obtain a 3D perovskite precursor solution. Heat it to 70 °C for crystal growth. Take out the CsPbBr2I1 crystal after 3 to 5 days.

[0072] (2) Use microcrystalline wax to mask the CsPbBr2I1 crystal to ensure that the 0D perovskite crystal only grows on the exposed surface, and fix the crystal on the quartz wafer with microcrystalline wax.

[0073] (3) Dissolve 41.6 g of CsBr and 14.68 g of PbBr2 in a mixed solution of 10 ml of DMSO and 40 ml of DMF and stir at 55 °C for 12 h. The precursor concentration is 0.8 mol / L. Then filter with a PTFE filter with a pore size of 0.22 μm to obtain a 0D perovskite precursor solution. Place the 3D perovskite single crystal and substrate in step (2) and heat to 70 °C for crystal growth for 3 to 5 days.

[0074] (4) The composite material and substrate grown in step (3) are removed from the precursor solution, heated to 87° C. to melt the microcrystalline wax, the composite material is removed from the substrate, and the crystal surface is rinsed with anhydrous ethanol, and finally dried.

[0075] The Au electrode was evaporated on the surface of the prepared perovskite composite material and used for nuclear radiation detection. The results showed that it had satisfactory sensitivity and detection stability. The perovskite composite material was also tested to have good mechanical stability and thermal stability.

[0076] Example 3

[0077] Preparation of perovskite composites for nuclear radiation detection, including 3D perovskite CsPbBr 2.2 I 0.8 and 0D perovskite Cs4PbBr 1.5 I 4.5 The heterojunction structure formed.

[0078] (1) 1.7 g of CsBr, 8.32 g of CsI, and 14.68 g of PbBr2 were dissolved in a mixed solution of 20 ml of DMSO and 30 ml of DMF and stirred at 55 °C for 12 h. The precursor concentration was 0.8 mol / L. The solution was then filtered through a PTFE filter with a pore size of 0.22 μm to obtain a 3D perovskite precursor solution. The solution was heated to 60 °C for crystal growth. After 3 to 5 days, CsPbBr was taken out. 2.2 I 0.8 Crystal.

[0079] (2) Use microcrystalline wax to treat CsPbBr 2.2 I 0.8 The crystals are masked to ensure that 0D perovskite crystals grow only on the exposed surface, and the crystals are fixed to the quartz wafer with microcrystalline wax.

[0080] (3) Dissolve 12.78g of CsBr, 26g of CsI, and 18.44g of PbI2 in a mixed solution of 10ml of DMSO and 40ml of DMF and stir at 55°C for 12h. The precursor concentration is 0.8mol / L. Then filter with a PTFE filter with a pore size of 0.22μm to obtain a 0D perovskite precursor solution. Place the 3D perovskite single crystal and substrate in step (2) and heat to 75°C for crystal growth for 3-5 days.

[0081] (4) The composite material and substrate grown in step (3) are removed from the precursor solution, heated to 90° C. to melt the microcrystalline wax, the composite material is removed from the substrate, and the crystal surface is rinsed with anhydrous ethanol, and finally dried.

[0082] The Au electrode was evaporated on the surface of the prepared perovskite composite material and used for nuclear radiation detection. The results showed that it had satisfactory sensitivity and detection stability. The perovskite composite material was also tested to have good mechanical stability and thermal stability.

[0083] Example 4

[0084] Preparation of perovskite composite materials for nuclear radiation detection, including a heterojunction structure formed by 3D perovskite CsPbBr2I1 and 0D perovskite Cs4PbBrI5.

[0085] (1) Dissolve 15.6 g of CsI and 22.02 g of PbBr2 in a mixed solution of 25 ml of DMSO and 25 ml of DMF and stir at 55 °C for 12 h. The precursor concentration is 1.2 mol / L. Then filter with a PTFE filter with a pore size of 0.22 μm to obtain a 3D perovskite precursor solution. Heat it to 100 °C for crystal growth. Take out the CsPbBr2I1 crystal after 3 to 5 days.

[0086] (2) Use microcrystalline wax to mask the CsPbBr2I1 crystal to ensure that the 0D perovskite crystal only grows on the exposed surface, and fix the crystal on the silicon wafer with microcrystalline wax.

[0087] (3) Dissolve 12.78g of CsBr, 46.8g of CsI, and 27.66g of PbI2 in a mixed solution of 20ml of DMSO and 30ml of DMF and stir at 55°C for 12h. The precursor concentration is 1.2mol / L. Then filter with a PTFE filter with a pore size of 0.22μm to obtain a 0D perovskite precursor solution. Place the 3D perovskite single crystal and substrate in step (2) and heat to 80°C for crystal growth for 3-5 days.

[0088] (4) The composite material and substrate grown in step (3) are removed from the precursor solution, heated to 92° C. to melt the microcrystalline wax, the composite material is removed from the substrate, and the crystal surface is rinsed with anhydrous ethanol, and finally dried.

[0089] The Au electrode was evaporated on the surface of the prepared perovskite composite material and used for nuclear radiation detection. The results showed that it had satisfactory sensitivity and detection stability. The perovskite composite material was also tested to have good mechanical stability and thermal stability.

[0090] 0D perovskite single crystal CsPbBr with different but similar materials 3-X I X 3D perovskite single crystal Cs4PbBr Y I 6-Y After forming the heterojunction structure, the ion migration of the 3D perovskite single crystal can be suppressed to improve its detection stability, and the perovskite composite material with this structure has good mechanical stability and thermal stability. The perovskite composite material can be used to form a highly sensitive and stable nuclear radiation detector.

[0091] Independent of any theory, the present invention reduces the ion migration phenomenon existing in 3D perovskite by forming a heterojunction structure, stabilizes the dark current baseline, and improves the electrical properties of 3D perovskite; 3D perovskite and 0D perovskite are simultaneously doped with multiple halogens to adjust the lattice constants of the two crystals, thereby obtaining heterojunction structures with different characteristics and expanding their application range; a microcrystalline wax mask is used to achieve directional growth of the heterojunction structure, which is insoluble in the polar solvent that constitutes the precursor, and makes the resulting perovskite composite material easy to peel off from the crystal surface.

[0092] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A perovskite composite material for nuclear radiation detection, characterized in that: The perovskite composite material comprises: 3D perovskite single crystal CsPbBr 3-X I X , where X = 0.3~1; and 0D perovskite single crystal Cs4PbBr on a partial surface of the 3D perovskite single crystal Y I 6-Y , where Y = 1 ~ 2.5, The 0D perovskite single crystal and the 3D perovskite single crystal form a heterojunction structure.

2. The perovskite composite material according to claim 1, characterized in that The 0D perovskite single crystal forms a single crystal layer that completely covers one crystal plane of the 3D perovskite single crystal.

3. A method for preparing a perovskite composite material, characterized in that: The method comprises the following steps: (1) Growth of 3D perovskite single crystal CsPbBr 3-X I X , where X = 0.3~1; (2) fixing the 3D perovskite single crystal in step (1) on a substrate using microcrystalline wax and using the microcrystalline wax as a mask to expose a portion of the surface of the 3D perovskite single crystal; (3) placing the 3D perovskite single crystal and the substrate in step (2) into a 0D perovskite precursor solution and heating at a temperature lower than the melting temperature of the microcrystalline wax to grow a 0D perovskite single crystal on the surface of the portion of the 3D perovskite single crystal to form a heterojunction structure, thereby obtaining a perovskite composite material on the substrate, wherein the 0D perovskite single crystal is Cs4PbBr Y I 6-Y , where Y = 1~2.5; (4) The perovskite composite material on the substrate in step (3) is taken out from the 0D perovskite precursor solution, and heated to a temperature above the melting temperature of the microcrystalline wax to melt the microcrystalline wax, so as to separate the perovskite composite material from the substrate.

4. The method according to claim 3, characterized in that In step (1), the 3D perovskite single crystal is prepared by heating a 3D perovskite precursor solution at 60-100° C., wherein the 3D perovskite precursor solution is a solution of bromide and iodide salts of Cs and Pb.

5. The method according to claim 3, characterized in that: The 0D perovskite precursor solution in step (3) is a solution of bromide and iodide salts of Cs and Pb.

6. The method according to claim 4 or 5, characterized in that: The concentration of the precursor in the 3D perovskite precursor solution in step (1) or the 0D perovskite precursor solution in step (3) is 0.8-1.2 mol / L, and the solvent used is a mixed solvent of dimethyl sulfoxide (DMSO) and N,N-dimethylformamide (DMF), and the volume ratio of the two solvents is DMSO:DMF=1:1-1:

4.

7. The method according to claim 3, characterized in that The substrate is a quartz wafer or a silicon wafer.

8. The method according to claim 3, characterized in that The melting temperature of the microcrystalline wax is 87~92℃.

9. A nuclear radiation detector, characterized in that: The nuclear radiation detector comprises: The perovskite composite material according to any one of claims 1 to 2 or the perovskite composite material obtained by the method according to any one of claims 3 to 8; and Detector electrodes electrically connected to the 3D perovskite single crystal and the 0D perovskite single crystal in the heterojunction structure in the perovskite composite material, respectively.

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