Preparation method of fast neutron direct detector based on organic-inorganic hybrid perovskite single crystal MAPbBr3

Abstract

The invention discloses a preparation method of a fast neutron direct detector based on organic and inorganic hybrid perovskite single crystals MAPbBr3, and belongs to the field of fast neutron detectors. The invention aims to solve the problems of low detection efficiency and complex preparation process caused by the fact that an existing semiconductor fast neutron detector needs an additional conversion layer. The high-quality organic-inorganic hybrid perovskite single crystal MAPbBr3 is grown through the inverse temperature crystallization method and is used for preparing the fast neutron semiconductor direct detector, and the fast neutron semiconductor direct detector integrates fast neutron capture and detection on the atomic scale, so that a conversion layer does not need to be additionally arranged, and the cost is low. The problems of complex process preparation, low secondary charged particle injection efficiency and low detection efficiency caused by the fact that an existing traditional fast neutron semiconductor direct detector needs an additional conversion layer are solved.

Description

Technical Field

[0001] The present invention belongs to the field of fast neutron detectors, and in particular relates to a method for preparing a fast neutron direct detector based on an organic-inorganic hybrid perovskite single crystal MAPbBr3. Background Art

[0002] Fast neutron detectors play an important role in nuclear safety monitoring, high energy physics, medical treatment, industrial non-destructive testing, geological and energy exploration, and neutron imaging. For traditional fast neutron semiconductor detectors, it is necessary to introduce a conversion layer containing H elements and other elements with a high neutron scattering cross section to improve neutron capture. However, the secondary charged particles generated by fast neutrons in the conversion layer will be severely scattered and absorbed and cannot be fully injected into the detector, resulting in low detection efficiency. Therefore, looking for a semiconductor material that integrates the two functions of neutron capture and detection can not only greatly reduce self-absorption and thus improve detection efficiency, but also simplify the process.

[0003] Organic-inorganic hybrid perovskite materials contain hydrogen-rich organic molecules and inorganic octahedral structures with excellent charge transfer properties. The organic component can capture fast neutrons, and the inorganic component is conducive to the transfer of charges. The fast neutron detector prepared by it can directly detect fast neutrons without the need for an external conversion layer. Summary of the invention

[0004] The purpose of the present invention is to solve the problem that the existing semiconductor fast neutron detectors require an external conversion layer, resulting in low detection efficiency and complex preparation process, and to provide a method for preparing a fast neutron direct detector based on organic-inorganic hybrid perovskite single crystal MAPbBr3.

[0005] A method for preparing a fast neutron direct detector based on an organic-inorganic hybrid perovskite single crystal MAPbBr3 is specifically completed in the following steps:

[0006] 1. Weigh methyl ammonium bromide and lead bromide to obtain raw materials; dissolve the raw materials in N,N-dimethylformamide to obtain a precursor solution;

[0007] 2. Dissolving the precursor solution by ultrasonication to achieve sufficient dissolution equilibrium and obtain a transparent saturated precursor solution;

[0008] 3. Place the transparent precursor saturated solution in an oil bath, heat the oil bath to a specific temperature and keep it warm for a period of time to obtain a preliminary organic-inorganic hybrid perovskite single crystal MAPbBr3;

[0009] 4. taking out the preliminary organic-inorganic hybrid perovskite single crystal MAPbBr3, washing it several times, and drying it to obtain a dry organic-inorganic hybrid perovskite single crystal MAPbBr3;

[0010] 5. Vapor-depositing a metal electrode material on one surface or two opposite surfaces of a dry organic-inorganic hybrid perovskite single crystal MAPbBr3 to achieve ohmic or Schottky contact between the metal electrode and the single crystal MAPbBr3, thereby obtaining a single crystal with a metal electrode on the surface;

[0011] 6. Fix the single crystal with a metal electrode on the surface on a base with a metal pin, and then connect the metal electrode on the surface of the single crystal to the pin through a wire to obtain a vertical or planar fast neutron direct detector based on the organic-inorganic hybrid perovskite single crystal MAPbBr3.

[0012] The advantages of the present invention are as follows:

[0013] The present invention grows high-quality organic-inorganic hybrid perovskite single crystal MAPbBr3 by inversion crystallization method, with a hydrogen concentration of 2.87×10 22 ncm -3 ; The single crystal material has both organic and inorganic components. The H atoms contained in the organic component have a large fast neutron scattering cross section, and the theoretical detection efficiency can reach 100%; the octahedral structure of the inorganic component has excellent charge transfer characteristics, which is conducive to charge collection and detection; therefore, the fast neutron semiconductor direct detector prepared using the organic-inorganic hybrid perovskite single crystal MAPbBr3 does not require the introduction of an external conversion layer, which greatly improves the fast neutron detection efficiency, and the preparation process is simple and the cost is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a photo of the organic-inorganic hybrid perovskite single crystal MAPbBr3 prepared in Example 1;

[0015] Figure 2 A photograph of a vertical fast neutron semiconductor direct detector based on an organic-inorganic hybrid perovskite single crystal MAPbBr3 prepared in Application Example 1;

[0016] Figure 3 XRD patterns of the organic-inorganic hybrid perovskite single crystal MAPbBr3, powder, and theoretical calculation prepared in Example 1;

[0017] Figure 4 The photoluminescence PL image of the organic-inorganic hybrid perovskite single crystal MAPbBr3 prepared in Example 1;

[0018] Figure 5 This is a signal response diagram of the vertical fast neutron semiconductor direct detector based on organic-inorganic hybrid perovskite single crystal MAPbBr3 prepared in Example 1 to fast neutrons generated by a DT tube neutron source;

[0019] Figure 6The pulse height spectrum of fast neutrons generated by the DT tube neutron source collected by the vertical fast neutron semiconductor direct detector based on organic-inorganic hybrid perovskite single crystal MAPbBr3 prepared in Example 1. DETAILED DESCRIPTION

[0020] Specific implementation method 1: This implementation method is a method for preparing a fast neutron direct detector based on an organic-inorganic hybrid perovskite single crystal MAPbBr3, which is specifically completed in the following steps:

[0021] 1. Weigh methyl ammonium bromide and lead bromide to obtain raw materials; dissolve the raw materials in N,N-dimethylformamide to obtain a precursor solution;

[0022] 2. Dissolving the precursor solution by ultrasonication to achieve sufficient dissolution equilibrium and obtain a transparent saturated precursor solution;

[0023] 3. Place the transparent precursor saturated solution in an oil bath, heat the oil bath to a specific temperature and keep it warm for a period of time to obtain a preliminary organic-inorganic hybrid perovskite single crystal MAPbBr3;

[0024] 4. taking out the preliminary organic-inorganic hybrid perovskite single crystal MAPbBr3, washing it several times, and drying it to obtain a dry organic-inorganic hybrid perovskite single crystal MAPbBr3;

[0025] 5. Vapor-depositing a metal electrode material on one surface or two opposite surfaces of a dry organic-inorganic hybrid perovskite single crystal MAPbBr3 to achieve ohmic or Schottky contact between the metal electrode and the single crystal MAPbBr3, thereby obtaining a single crystal with a metal electrode on the surface;

[0026] 6. Fix the single crystal with a metal electrode on the surface on a base with a metal pin, and then connect the metal electrode on the surface of the single crystal to the pin through a wire to obtain a vertical or planar fast neutron direct detector based on the organic-inorganic hybrid perovskite single crystal MAPbBr3.

[0027] Specific embodiment 2: This embodiment differs from specific embodiment 1 in that the molar ratio of methylamine bromide to lead bromide in step 1 is 1:(0.7-1). The other steps are the same as those in specific embodiment 1.

[0028] Specific implementation method 3: This implementation method is different from specific implementation method 1 or 2 in that the concentration of the raw material in the precursor solution in step 1 is 1 mol / L to 1.25 mol / L. The other steps are the same as those in specific implementation method 1 or 2.

[0029] Specific embodiment 4: This embodiment differs from specific embodiments 1 to 3 in that the power of ultrasonic dissolution in step 2 is 240 W and the time of ultrasonic dissolution is 5 to 40 minutes. The other steps are the same as those of specific embodiments 1 to 3.

[0030] Specific embodiment 5: This embodiment differs from specific embodiments 1 to 4 in that the specific temperature in step 3 is 60° C. to 90° C., and the insulation time is 2 h to 48 h. The other steps are the same as those in specific embodiments 1 to 4.

[0031] Specific embodiment 6: This embodiment differs from specific embodiments 1 to 5 in that: the cleaning described in step 4 uses n-hexane or acetone as the cleaning liquid, and the number of cleaning times is 3 to 5 times; the drying temperature described in step 4 is 40°C to 70°C, and the drying time is 0.5h to 2h. The other steps are the same as specific embodiments 1 to 5.

[0032] Specific embodiment 7: This embodiment differs from specific embodiments 1 to 6 in that the metal electrode material in step 5 is gold or silver. The other steps are the same as those in specific embodiments 1 to 6.

[0033] Specific embodiment 8: This embodiment differs from specific embodiments 1 to 7 in that the thickness of the metal electrode on the surface of the single crystal in step 5 is 60 nm to 200 nm. The other steps are the same as those of specific embodiments 1 to 7.

[0034] Specific implementation method 9: This implementation method is different from specific implementation methods 1 to 8 in that: the wire in step 6 is a metal wire; the metal wire is a gold wire, a silver wire or a copper wire; the diameter of the metal wire is 0.05 mm to 0.5 mm. The other steps are the same as specific implementation methods 1 to 8.

[0035] Specific embodiment 10: This embodiment differs from specific embodiments 1 to 9 in that the material of the metal pins described in step 6 is gold-plated nickel. The other steps are the same as those of specific embodiments 1 to 9.

[0036] The following examples are used to verify the beneficial effects of the present invention:

[0037] Example 1: A method for preparing a vertical fast neutron semiconductor direct detector based on organic-inorganic hybrid perovskite single crystal MAPbBr3 is specifically completed by the following steps:

[0038] 1. Weigh methyl ammonium bromide (MABr) and lead bromide (PbBr2) to obtain raw materials; dissolve the raw materials in N,N-dimethylformamide (DMF) to obtain a precursor solution;

[0039] The molar ratio of methylammonium bromide to lead bromide in step 1 is 1:1;

[0040] The concentration of the raw material in the precursor solution described in step 1 is 1 mol / L;

[0041] 2. Dissolving the precursor solution by ultrasonication to achieve sufficient dissolution equilibrium and obtain a transparent saturated precursor solution;

[0042] The power of ultrasonic dissolution in step 2 is 240W, and the time of ultrasonic dissolution is 10min;

[0043] 3. Place the transparent precursor saturated solution in an oil bath, heat the oil bath to a specific temperature and keep it warm for a period of time to obtain a preliminary organic-inorganic hybrid perovskite single crystal MAPbBr3;

[0044] The specific temperature described in step 3 is 80° C., and the insulation time is 24 hours;

[0045] 4. The preliminary organic-inorganic hybrid perovskite single crystal MAPbBr3 was taken out, washed with n-hexane three times, and then placed in an oven at 40°C for 0.5h to obtain a dry organic-inorganic hybrid perovskite single crystal MAPbBr3;

[0046] The size of the organic-inorganic hybrid perovskite single crystal MAPbBr3 described in step 4 is 6 mm×5 mm×1.3 mm;

[0047] 5. On two opposite surfaces of the dried organic-inorganic hybrid perovskite single crystal MAPbBr3, gold electrodes with a thickness of 80 nm are respectively deposited to achieve ohmic and Schottky contact between the gold electrode and the single crystal MAPbBr3, thereby obtaining a single crystal with a gold electrode on the surface;

[0048] 6. Fix the single crystal with gold electrodes on the surface on a base with metal pins, and then connect the gold electrodes on the two surfaces of the single crystal to the pins through gold wires with a diameter of 0.05 mm using silver paste to obtain a vertical fast neutron semiconductor direct detector based on organic-inorganic hybrid perovskite single crystal MAPbBr3;

[0049] The metal pins described in step six are made of gold-plated nickel.

[0050] Example 2: A method for preparing a vertical fast neutron semiconductor direct detector based on organic-inorganic hybrid perovskite single crystal MAPbBr3 is specifically completed by the following steps:

[0051] 1. Weigh methyl ammonium bromide (MABr) and lead bromide (PbBr2) to obtain raw materials; dissolve the raw materials in N,N-dimethylformamide (DMF) to obtain a precursor solution;

[0052] The molar ratio of methylammonium bromide to lead bromide in step 1 is 1:1;

[0053] The concentration of the raw material in the precursor solution described in step 1 is 1.2 mol / L;

[0054] 2. Dissolving the precursor solution by ultrasonication to achieve sufficient dissolution equilibrium and obtain a transparent saturated precursor solution;

[0055] The power of ultrasonic dissolution in step 2 is 240W, and the time of ultrasonic dissolution is 15min;

[0056] 3. Place the transparent precursor saturated solution in an oil bath, heat the oil bath to a specific temperature and keep it warm for a period of time to obtain a preliminary organic-inorganic hybrid perovskite single crystal MAPbBr3;

[0057] The specific temperature described in step 3 is 75° C., and the insulation time is 48 hours;

[0058] 4. The preliminary organic-inorganic hybrid perovskite single crystal MAPbBr3 was taken out, washed with n-hexane 4 times, and then placed in an oven at 50°C for 1 hour to obtain a dry organic-inorganic hybrid perovskite single crystal MAPbBr3;

[0059] The size of the organic-inorganic hybrid perovskite single crystal MAPbBr3 described in step 4 is 10 mm×8 mm×1.6 mm;

[0060] 5. On two opposite surfaces of the dried organic-inorganic hybrid perovskite single crystal MAPbBr3, silver electrodes with a thickness of 80 nm are respectively deposited to achieve ohmic and Schottky contact between the silver electrode and the single crystal MAPbBr3, thereby obtaining a single crystal with a silver electrode on the surface;

[0061] 6. Fix the single crystal with silver electrodes on the surface on a base with metal pins, and then connect the silver electrodes on the two surfaces of the single crystal to the pins through silver wires with a diameter of 0.05 mm using silver paste to obtain a vertical fast neutron semiconductor direct detector based on organic-inorganic hybrid perovskite single crystal MAPbBr3;

[0062] The metal pins described in step six are made of gold-plated nickel.

[0063] Example 3: A method for preparing a planar fast neutron semiconductor direct detector based on organic-inorganic hybrid perovskite single crystal MAPbBr3 is specifically completed by the following steps:

[0064] 1. Weigh methyl ammonium bromide (MABr) and lead bromide (PbBr2) to obtain raw materials; dissolve the raw materials in N,N-dimethylformamide (DMF) to obtain a precursor solution;

[0065] The molar ratio of methylammonium bromide to lead bromide in step 1 is 1:1;

[0066] The concentration of the raw material in the precursor solution described in step 1 is 1.25 mol / L;

[0067] 2. Dissolving the precursor solution by ultrasonication to achieve sufficient dissolution equilibrium and obtain a transparent saturated precursor solution;

[0068] The power of the ultrasonic dissolution in step 2 is 240W, and the time of ultrasonic dissolution is 20min;

[0069] 3. Place the transparent precursor saturated solution in an oil bath, heat the oil bath to a specific temperature and keep it warm for a period of time to obtain a preliminary organic-inorganic hybrid perovskite single crystal MAPbBr3;

[0070] The specific temperature described in step 3 is 70° C., and the insulation time is 24 hours;

[0071] 4. The preliminary organic-inorganic hybrid perovskite single crystal MAPbBr3 was taken out, washed with n-hexane for 5 times, and then placed in an oven at 60°C for 2 hours to obtain a dry organic-inorganic hybrid perovskite single crystal MAPbBr3;

[0072] The size of the organic-inorganic hybrid perovskite single crystal MAPbBr3 described in step 4 is 5 mm×5 mm×1.2 mm;

[0073] 5. On one surface of the dried organic-inorganic hybrid perovskite single crystal MAPbBr3, a 100 nm thick interdigitated gold electrode is deposited to achieve ohmic and Schottky contact between the interdigitated gold electrode and the single crystal MAPbBr3, thereby obtaining a single crystal with an interdigitated gold electrode on the surface;

[0074] 6. Fix the single crystal with interdigitated gold electrodes on the surface on a base with metal pins, and then connect the interdigitated gold electrodes on one surface of the single crystal to the pins through silver wires with a diameter of 0.05 mm using silver paste to obtain a planar fast neutron semiconductor direct detector based on organic-inorganic hybrid perovskite single crystal MAPbBr3;

[0075] The metal pins described in step six are made of gold-plated nickel.

[0076] Example 4: A method for preparing a vertical fast neutron semiconductor direct detector based on organic-inorganic hybrid perovskite single crystal MAPbBr3 is specifically completed by the following steps:

[0077] 1. Weigh methyl ammonium bromide (MABr) and lead bromide (PbBr2) to obtain raw materials; dissolve the raw materials in N,N-dimethylformamide (DMF) to obtain a precursor solution;

[0078] The molar ratio of methyl ammonium bromide to lead bromide in step 1 is 1:0.8;

[0079] The concentration of the raw material in the precursor solution described in step 1 is 1 mol / L;

[0080] 2. Dissolving the precursor solution by ultrasonication to achieve sufficient dissolution equilibrium and obtain a transparent saturated precursor solution;

[0081] The power of ultrasonic dissolution in step 2 is 240W, and the time of ultrasonic dissolution is 10min;

[0082] 3. Place the transparent precursor saturated solution in an oil bath, heat the oil bath to a specific temperature and keep it warm for a period of time to obtain a preliminary organic-inorganic hybrid perovskite single crystal MAPbBr3;

[0083] The specific temperature described in step 3 is 70° C., and the insulation time is 48 hours;

[0084] 4. The preliminary organic-inorganic hybrid perovskite single crystal MAPbBr3 was taken out, washed with n-hexane 4 times, and then placed in an oven at 40°C for 1.5 hours to obtain a dry organic-inorganic hybrid perovskite single crystal MAPbBr3;

[0085] The size of the organic-inorganic hybrid perovskite single crystal MAPbBr3 described in step 4 is 7 mm×5 mm×1.4 mm;

[0086] 5. On two opposite surfaces of the dried organic-inorganic hybrid perovskite single crystal MAPbBr3, a gold electrode with a thickness of 80 nm and a silver electrode with a thickness of 80 nm are respectively deposited to achieve ohmic and Schottky contacts between the gold electrode, the silver electrode and the single crystal MAPbBr3, thereby obtaining a single crystal with electrodes on the surface;

[0087] 6. Fix the single crystal with the electrode on the surface on a base with metal pins, and then connect the electrodes on the two surfaces of the single crystal to the pins through gold wires with a diameter of 0.1 mm using silver paste to obtain a vertical fast neutron semiconductor direct detector based on organic-inorganic hybrid perovskite single crystal MAPbBr3;

[0088] The metal pins described in step six are made of gold-plated nickel.

[0089] Example 5: A method for preparing a vertical fast neutron semiconductor direct detector based on organic-inorganic hybrid perovskite single crystal MAPbBr3 is specifically completed in the following steps:

[0090] 1. Weigh methyl ammonium bromide (MABr) and lead bromide (PbBr2) to obtain raw materials; dissolve the raw materials in N,N-dimethylformamide (DMF) to obtain a precursor solution;

[0091] The molar ratio of methyl ammonium bromide to lead bromide in step 1 is 1:0.8;

[0092] The concentration of the raw material in the precursor solution described in step 1 is 1.25 mol / L;

[0093] 2. Dissolving the precursor solution by ultrasonication to achieve sufficient dissolution equilibrium and obtain a transparent saturated precursor solution;

[0094] The power of ultrasonic dissolution in step 2 is 240W, and the time of ultrasonic dissolution is 15min;

[0095] 3. Place the transparent precursor saturated solution in an oil bath, heat the oil bath to a specific temperature and keep it warm for a period of time to obtain a preliminary organic-inorganic hybrid perovskite single crystal MAPbBr3;

[0096] The specific temperature described in step 3 is 70° C., and the insulation time is 24 hours;

[0097] 4. The preliminary organic-inorganic hybrid perovskite single crystal MAPbBr3 was taken out, washed with n-hexane for 3 times, and then placed in an oven at 50°C for 1 hour to obtain a dry organic-inorganic hybrid perovskite single crystal MAPbBr3;

[0098] The size of the organic-inorganic hybrid perovskite single crystal MAPbBr3 described in step 4 is 5 mm×4 mm×1.1 mm;

[0099] 5. On two opposite surfaces of the dried organic-inorganic hybrid perovskite single crystal MAPbBr3, respectively, gold electrodes with a thickness of 100 nm are evaporated to achieve ohmic and Schottky contact between the gold electrode and the single crystal MAPbBr3, thereby obtaining a single crystal with a gold electrode on the surface;

[0100] 6. Fix the single crystal with gold electrodes on the surface on a base with metal pins, and then connect the gold electrodes on the two surfaces of the single crystal to the pins through silver wires with a diameter of 0.1 mm using silver paste to obtain a vertical fast neutron semiconductor direct detector based on organic-inorganic hybrid perovskite single crystal MAPbBr3;

[0101] The metal pins described in step six are made of gold-plated nickel.

[0102] Example 6: A method for preparing a planar fast neutron semiconductor direct detector based on organic-inorganic hybrid perovskite single crystal MAPbBr3 is specifically completed by the following steps:

[0103] 1. Weigh methyl ammonium bromide (MABr) and lead bromide (PbBr2) to obtain raw materials; dissolve the raw materials in N,N-dimethylformamide (DMF) to obtain a precursor solution;

[0104] The molar ratio of methyl ammonium bromide to lead bromide in step 1 is 1:0.8;

[0105] The concentration of the raw material in the precursor solution described in step 1 is 1.25 mol / L;

[0106] 2. Dissolving the precursor solution by ultrasonication to achieve sufficient dissolution equilibrium and obtain a transparent saturated precursor solution;

[0107] The power of the ultrasonic dissolution in step 2 is 240W, and the time of ultrasonic dissolution is 20min;

[0108] 3. Place the transparent precursor saturated solution in an oil bath, heat the oil bath to a specific temperature and keep it warm for a period of time to obtain a preliminary organic-inorganic hybrid perovskite single crystal MAPbBr3;

[0109] The specific temperature described in step 3 is 70° C., and the insulation time is 48 hours;

[0110] 4. The preliminary organic-inorganic hybrid perovskite single crystal MAPbBr3 was taken out, washed with n-hexane 4 times, and then placed in an oven at 60°C for 1.5 hours to obtain a dry organic-inorganic hybrid perovskite single crystal MAPbBr3;

[0111] The size of the organic-inorganic hybrid perovskite single crystal MAPbBr3 described in step 4 is 6 mm×6 mm×1.2 mm;

[0112] 5. On one surface of the dried organic-inorganic hybrid perovskite single crystal MAPbBr3, a 100 nm thick interdigitated silver electrode is deposited to achieve ohmic and Schottky contact between the interdigitated silver electrode and the single crystal MAPbBr3, thereby obtaining a single crystal with an interdigitated silver electrode on the surface;

[0113] 6. Fixing the single crystal with interdigitated silver electrodes on the surface on a base with metal pins, and then connecting the interdigitated silver electrodes on one surface of the single crystal to the pins with silver paste through silver wires with a diameter of 0.05 mm, to obtain a planar fast neutron semiconductor direct detector based on organic-inorganic hybrid perovskite single crystal MAPbBr3;

[0114] The metal pins described in step six are made of gold-plated nickel.

[0115] Figure 1 This is a photo of the organic-inorganic hybrid perovskite single crystal MAPbBr3 prepared in Example 1;

[0116] from Figure 1 It can be seen that the single crystal has high transparency.

[0117] Figure 3 XRD patterns of the organic-inorganic hybrid perovskite single crystal MAPbBr3, powder, and theoretical calculation prepared in Example 1;

[0118] from Figure 3 It can be seen that the single crystal has good crystallinity.

[0119] Figure 4 The photoluminescence PL image of the organic-inorganic hybrid perovskite single crystal MAPbBr3 prepared in Example 1;

[0120] from Figure 4 It can be seen that it has excellent luminescence properties.

[0121] Figure 5 This is a signal response diagram of the vertical fast neutron semiconductor direct detector based on organic-inorganic hybrid perovskite single crystal MAPbBr3 prepared in Example 1 to fast neutrons generated by a DT tube neutron source;

[0122] from Figure 5 It can be seen that the pulse signal generated under low bias voltage has a higher signal-to-noise ratio.

[0123] Figure 6 The pulse height spectrum of fast neutrons generated by the DT tube neutron source collected by the vertical fast neutron semiconductor direct detector based on organic-inorganic hybrid perovskite single crystal MAPbBr3 prepared in Example 1.

[0124] from Figure 6 It can be seen that the pulse height spectrum is step-shaped, which is caused by the isotropic scattering and uniform energy distribution of the recoil protons.

[0125] In summary, the present invention obtains single crystals with high crystallization quality by changing the molar ratio of methyl ammonium bromide (MABr) and lead bromide (PbBr2) raw materials and setting different growth temperatures and holding times when adopting the inversion crystallization method. In addition, ohmic and Schottky contacts between the metal electrode and the MAPbBr3 single crystal semiconductor material are achieved by evaporating different metal electrode materials. Finally, vertical and planar fast neutron semiconductor direct detectors are prepared. This organic-inorganic hybrid perovskite single crystal detector integrates fast neutron capture and detection, avoids the introduction of a conversion layer compared to traditional semiconductor fast neutron detectors, greatly improves the detection efficiency of fast neutrons, and simplifies the preparation process.

Claims

1. A method for preparing a fast neutron direct detector based on organic-inorganic hybrid perovskite single crystal MAPbBr3, characterized in that The preparation method is specifically completed according to the following steps:

1. Weigh methyl ammonium bromide and lead bromide to obtain raw materials; dissolve the raw materials in N,N-dimethylformamide to obtain a precursor solution; 2. Dissolving the precursor solution by ultrasonication to achieve sufficient dissolution equilibrium and obtain a transparent saturated precursor solution; 3. Place the transparent precursor saturated solution in an oil bath, heat the oil bath to a specific temperature and keep it warm for a period of time to obtain a preliminary organic-inorganic hybrid perovskite single crystal MAPbBr3; 4. taking out the preliminary organic-inorganic hybrid perovskite single crystal MAPbBr3, washing it several times, and drying it to obtain a dry organic-inorganic hybrid perovskite single crystal MAPbBr3; 5. Vapor-depositing a metal electrode material on one surface or two opposite surfaces of a dry organic-inorganic hybrid perovskite single crystal MAPbBr3 to achieve ohmic or Schottky contact between the metal electrode and the single crystal MAPbBr3, thereby obtaining a single crystal with a metal electrode on the surface; 6. Fix the single crystal with a metal electrode on the surface on a base with a metal pin, and then connect the metal electrode on the surface of the single crystal to the pin through a wire to obtain a vertical or planar fast neutron direct detector based on the organic-inorganic hybrid perovskite single crystal MAPbBr3.

2. The method for preparing a fast neutron direct detector based on an organic-inorganic hybrid perovskite single crystal MAPbBr3 according to claim 1, characterized in that The molar ratio of methyl ammonium bromide to lead bromide in step 1 is 1:(0.7-1).

3. The method for preparing a fast neutron direct detector based on an organic-inorganic hybrid perovskite single crystal MAPbBr3 according to claim 1, characterized in that The concentration of the raw material in the precursor solution described in step 1 is 1 mol / L to 1.25 mol / L.

4. The method for preparing a fast neutron direct detector based on an organic-inorganic hybrid perovskite single crystal MAPbBr3 according to claim 1, characterized in that The power of the ultrasonic dissolution in step 2 is 240W, and the time of the ultrasonic dissolution is 5min to 40min.

5. The method for preparing a fast neutron direct detector based on an organic-inorganic hybrid perovskite single crystal MAPbBr3 according to claim 1, characterized in that The specific temperature described in step 3 is 60° C. to 90° C., and the insulation time is 2 h to 48 h.

6. The method for preparing a fast neutron direct detector based on an organic-inorganic hybrid perovskite single crystal MAPbBr3 according to claim 1, characterized in that The cleaning described in step 4 is performed using n-hexane or acetone as a cleaning liquid, and the number of cleaning times is 3 to 5 times; the drying temperature described in step 4 is 40° C. to 70° C., and the drying time is 0.5 h to 2 h.

7. The method for preparing a fast neutron direct detector based on organic-inorganic hybrid perovskite single crystal MAPbBr3 according to claim 1, characterized in that The metal electrode material described in step five is gold or silver.

8. The method for preparing a fast neutron direct detector based on organic-inorganic hybrid perovskite single crystal MAPbBr3 according to claim 1, characterized in that In step 5, the thickness of the metal electrode on the surface of the single crystal is 60nm to 200nm.

9. The method for preparing a fast neutron direct detector based on organic-inorganic hybrid perovskite single crystal MAPbBr3 according to claim 1, characterized in that The conductive wire described in step six is ​​a metal wire; the metal wire is a gold wire, a silver wire or a copper wire; the diameter of the metal wire is 0.05 mm to 0.5 mm.

10. The method for preparing a fast neutron direct detector based on organic-inorganic hybrid perovskite single crystal MAPbBr3 according to claim 1, characterized in that The metal pins described in step six are made of gold-plated nickel.

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