A preparation method of perovskite complex for X-ray detection and its product and application

Abstract

The present invention provides a preparation method of a perovskite complex for X-ray detection and its products and applications, the preparation method comprising: mixing perovskite with a solvent to obtain a mixture, drying, and obtaining. The present invention utilizes the affinity between lead halide perovskite and polar organic solvents, and synthesizes a perovskite-solvent complex by introducing an appropriate amount of polar solvent into the perovskite powder. The obtained solvent complex is soft in texture and has good processing flexibility. A dense and uniform perovskite wafer can be obtained under a relatively small pressure, and the complexed solvent is released during the tableting process. The solvent volatilization process can effectively promote recrystallization, perovskite crystal grain boundary fusion, and improve the charge transfer performance of the wafer. In addition, during the growth of the wafer, it can be integrated with a conductive substrate to prepare an efficient X-ray detector. This method is simple to operate, novel and unique, and a highly sensitive perovskite X-ray detector can be obtained, which has a good application prospect.

Description

Technical Field

[0001] The present invention belongs to the field of perovskite X-ray detection, and relates to a preparation method of a perovskite complex for X-ray detection, and a product and application thereof. Background Art

[0002] X-ray detection has been widely used in medical imaging, industrial inspection, safety inspection and other fields, and is closely related to people's lives. In order to reduce the radiation damage caused by high-dose X-rays, X-ray detectors are currently required to have higher sensitivity and lower detection limits. Generally, X-ray detectors have two different detection modes: direct and indirect. Indirect detection relies on scintillators for secondary photoelectric conversion, which inevitably suffers from difficult-to-overcome problems such as low efficiency and visible light dispersion, resulting in low detection sensitivity, high radiation dose, and poor spatial resolution. In contrast, direct X-ray detectors based on semiconductor materials can directly convert X-rays into electrical signals through a single photoelectric conversion, so they can have higher detection efficiency and lower detection limits. The development of new and efficient photosensitive semiconductor materials is the key to the application of direct X-ray imaging detectors.

[0003] Perovskite has great application potential in the field of direct X-ray detection due to its advantages such as large X-ray stopping energy, high carrier mobility, and long carrier lifetime. In order to fully absorb high-energy X-rays, the thickness of the perovskite active layer should reach hundreds of microns. At present, the application of perovskite in X-rays is mainly based on single crystals and thin films, but the growth of perovskite single crystals is time-consuming and difficult to prepare on a large scale. Due to the limited solubility of the precursor, it is also difficult to prepare a perovskite thick film that meets the requirements through a solution method. Compacting perovskite powder to form a polycrystalline perovskite wafer can construct a perovskite X-ray detection photosensitive layer with adjustable size and thickness, but the polycrystalline inorganic perovskite wafer prepared in this way usually contains many voids and grain boundaries, which seriously affects the efficiency and working stability of the X-ray detector, and is difficult to further integrate with the substrate circuit.

[0004] In summary, in order to further promote the application of perovskite materials in the field of X-ray detectors, it is necessary to improve the quality of perovskite crystals and perovskite thick films to prepare high-performance X-ray detectors. Summary of the invention

[0005] In view of the deficiencies of the prior art, the object of the present invention is to provide a method for preparing a perovskite complex for X-ray detection and its product and application.

[0006] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a method for preparing a perovskite complex for X-ray detection, the preparation method comprising: mixing perovskite with a solvent to obtain a mixture, and drying to obtain a perovskite complex;

[0008] The solvent includes a polar solvent A and a solvent B; the polar solvent A includes any one of DMF (dimethyl sulfoxide), DMSO (N,N-dimethylformamide), GBL (γ-butyrolactone) or NMP (N-methyl-2-pyrrolidone) or a combination of at least two thereof;

[0009] The perovskite comprises a chemical formula of X n Pb n Y 3n The lead halide perovskite, wherein n is 1 or an integer greater than 1 (for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, etc.), the X is each independently selected from any one of MA (methylamine), FA (formamidine) or Cs (cesium), and the Y is each independently selected from I or Br.

[0010] Preferably, the X n Pb n Y 3n For example, MAPbI3, MAPbBr3, FAPbI3, FAPbBr3, CsPbI3, CsPbBr3, MAPbI2Br, MAPbIBr2, FAPbI2Br, FAPbIBr2, CsPbI2Br, CsPbIBr2, MAFAPb2I6, MAFAPb2Br6, MAFAPb2I2Br4, MAFAPb2I4Br2, MA2Pb2I6, MA2Pb2Br6, FA2Pb2I6, FA2Pb2Br6, Cs2Pb2I6, Cs2Pb2Br6, MA3Pb3I9, MA3Pb3Br9, FA3Pb3I9, FA3Pb3Br9, Cs3Pb3I9, Cs3Pb3Br9, etc.

[0011] Preferably, the solvent B comprises any one of chloroform, toluene, isopropanol, acetone, chlorobenzene or ether, or a combination of at least two thereof.

[0012] Preferably, the mass ratio of perovskite to solvent in the mixture is 1:(5-20).

[0013] Specific numerical values ​​in the above (5-20) include 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, etc.

[0014] Preferably, the volume ratio of the polar solvent A to the solvent B is (1-10):(100-200).

[0015] Specific numerical values ​​in the above (1-10) are, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, etc.

[0016] Specific numerical values ​​in the above (100-200) include, for example, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, etc.

[0017] Preferably, the mixing temperature is 15-40°C, for example 15°C, 17°C, 20°C, 22°C, 25°C, 27°C, 30°C, 32°C, 35°C, 37°C, 40°C, etc., and the mixing time is 30-120min, for example 30min, 40min, 50min, 60min, 70min, 80min, 90min, 100min, 110min, 120min, etc.

[0018] Preferably, the mixing is carried out under stirring, and the stirring speed is 200-1000 rpm, for example, 200 rpm, 400 rpm, 500 rpm, 600 rpm, 800 rpm, 1000 rpm, etc.

[0019] Preferably, the drying temperature is 20-60°C, such as 20°C, 30°C, 40°C, 50°C, 60°C, etc.

[0020] Preferably, the drying step further comprises centrifuging the mixture and discarding the supernatant (discarding the solvent).

[0021] Preferably, the centrifugal rotation speed is 2000-6000 rpm, for example, 2000 rpm, 3000 rpm, 4000 rpm, 5000 rpm, 6000 rpm, etc.

[0022] Preferably, the perovskite is prepared by a preparation method comprising the following steps:

[0023] The lead halide, the halogen-containing compound and the organic solvent are mixed to obtain a precursor solution, which is mixed with an anti-solvent to precipitate a reaction product, and dried to obtain the perovskite;

[0024] The lead halide includes PbI2 and / or PbBr2; the halogen-containing compound includes any one of MAI (methylamine iodide), FAI (formamidine iodide), CsI, MABr (methylamine bromide), FABr (formamidine bromide) or CsBr, or a combination of at least two of them.

[0025] Preferably, the molar ratio of the lead halide to the halogen-containing compound is (1-2):(1-2).

[0026] Specific numerical values ​​in the above (1-2) include 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, etc.

[0027] The preferred molar ratio is 1:1.

[0028] Preferably, the organic solvent includes any one of DMF, DMSO, NMP or GBL, or a combination of at least two thereof.

[0029] Preferably, the anti-solvent comprises any one of chloroform, toluene, isopropanol, acetone, chlorobenzene or ether, or a combination of at least two thereof.

[0030] Preferably, the volume ratio of the organic solvent to the anti-solvent is (1-10):(10-200).

[0031] Specific numerical values ​​in the above (1-10) are, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, etc.

[0032] Specific numerical values ​​in the above (10-200) include, for example, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, etc.

[0033] In a second aspect, the present invention provides a perovskite complex prepared by the preparation method described in the first aspect.

[0034] In a third aspect, the present invention provides a method for preparing a perovskite wafer, the method comprising: preparing a perovskite complex by the preparation method described in the first aspect, and pressing the perovskite complex into a sheet;

[0035] Alternatively, the preparation method comprises: mixing the prepared perovskite complex with perovskite, and pressing the mixture into tablets to obtain the product.

[0036] In the present invention, the perovskite wafer can be obtained by pressing the perovskite complex alone, or the perovskite complex and perovskite can be mixed and pressed to obtain the perovskite wafer.

[0037] Preferably, in the mixing, the mass ratio of the perovskite complex to the perovskite is (1-10):(1-10).

[0038] 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, etc. in (1-10) above.

[0039] Preferably, the tableting is carried out under the conditions of 3-20 MPa and 80-150°C.

[0040] Specific values ​​among the above 3-20MPa include 3MPa, 4MPa, 5MPa, 6MPa, 7MPa, 8MPa, 9MPa, 10MPa, 11MPa, 12MPa, 13MPa, 14MPa, 15MPa, 16MPa, 17MPa, 18MPa, 19MPa, 20MPa, etc.

[0041] Specific values ​​among the above 80-150°C include 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, 140°C, 145°C, 150°C, etc.

[0042] Preferably, when the tabletting pressure is 5 MPa and the temperature is 100° C., the obtained wafer has a better surface morphology.

[0043] Preferably, the tableting time is 10-40 min, for example, 10 min, 15 min, 20 min, 25 min, 30 min, 35 min, 40 min, etc.

[0044] In the technical solution of the present invention, by selecting molds of different sizes and changing the mass of the powder (perovskite complex powder and optional perovskite powder), a chip with controllable size and thickness can be obtained; taking a mold size of 10mm×10mm as an example, 180mg-300mg of the above powder is weighed, and a chip with a thickness of 500μm to 1mm can be obtained by tableting.

[0045] Preferably, the tableting further includes annealing to ensure that all the residual solvent has been volatilized.

[0046] Preferably, the annealing temperature is 80-200°C, for example 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, etc., and the annealing time is 30-120min, for example 30min, 40min, 50min, 60min, 70min, 80min, 90min, 100min, 110min, 120min, etc.

[0047] In a fourth aspect, the present invention provides a perovskite wafer produced by the preparation method described in the third aspect.

[0048] In a fifth aspect, the present invention provides the use of the perovskite complex prepared by the preparation method as described in the first aspect or the perovskite wafer prepared by the preparation method as described in the third aspect in the preparation of an X-ray detector.

[0049] In a sixth aspect, the present invention provides an X-ray detector, the components of which include an active layer, an electrode and an optional transmission layer, and the material of the active layer includes a perovskite wafer prepared by the preparation method described in the third aspect.

[0050] The X-ray detector: ① can be a PIN or NIP photodiode device including an active layer, a transmission layer and an electrode, wherein the perovskite wafer is used as the active layer material; ② can only include an active layer and an electrode, wherein the perovskite wafer is used as the active layer material.

[0051] Preferably, the transport layer can be made of a transport layer material commonly used in the art, such as C 60 , BCP, PCBM, poly-TPD, PEDOT:PSS, NiO x , PTAA, TAPC, P3HT, TiO x 、MoO x , MoO3, V2O5, WO3 and other materials or a multilayer structure composed of them, and the thickness can be 1-300nm.

[0052] Preferably, the electrode can be made of conventional electrode materials in the art, such as metal electrodes such as Cu, Ag, Au, Al, Cr, or carbon electrodes, and the thickness can be 30-200 nm.

[0053] The numerical range described in the present invention not only includes the point values ​​listed above, but also includes any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0054] Compared with the prior art, the present invention has the following beneficial effects:

[0055] The following problems exist in the current prior art when using perovskite materials to prepare X-ray detectors: 1. The growth of perovskite single crystals takes a long time and is difficult to prepare on a large scale. 2. Due to the limited solubility of the precursor, it is also difficult to prepare a perovskite thick film that meets the requirements through the solution method. 3. The prepared perovskite powder is difficult to compact into wafers. Even if the compacted polycrystalline inorganic perovskite wafers contain many voids and grain boundaries, which seriously affect the efficiency and working stability of the X-ray detector, and it is difficult to further integrate with the substrate circuit.

[0056] The purpose of the present invention is to overcome the above problems and prepare a high-efficiency (high-sensitivity) X-ray detector using perovskite materials.

[0057] The preparation method provided by the present invention utilizes the affinity between lead halide perovskite and polar organic solvents, and synthesizes a perovskite-solvent complex by introducing an appropriate amount of polar solvent into the perovskite powder. The obtained solvent complex is soft in texture, has better processing flexibility, and can obtain dense and uniform perovskite wafers under relatively low pressure. In addition, the pressure applied during the tableting process can cause the solvent in the complex to be squeezed out. On the one hand, the solvent can be used as an adhesive to promote further bonding of the wafer to the substrate; on the other hand, the solvent can effectively promote recrystallization during volatilization, further promote grain boundary fusion on the wafer surface, improve charge transfer performance, and reduce dark current. In addition, during the growth of the wafer, it can be integrated with a conductive substrate (ITO glass, TFT or CMOS pixel chip), so that it can be used to prepare a high-efficiency X-ray detector (the light response sensitivity of the X-ray detector prepared by the perovskite-solvent complex provided by the present invention can reach 6737μC Gy air -1 cm -2 The method is simple to operate, novel and unique, and can obtain a perovskite X-ray detector that meets market demand, and has good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 These are the physical pictures of the MAPbI3 perovskite powder obtained in step 1 and the MAPbI3-DMSO complex powder obtained in step 3 in Example 1; A is a physical picture of the MAPbI3 perovskite powder, and B is a physical picture of the MAPbI3-DMSO complex powder.

[0059] Figure 2 X-ray diffraction (XRD) diagram of MAPbI3 obtained in step 1 and MAPbI3-DMF complex powder obtained in step 3 in Example 2.

[0060] Figure 3 This is a scanning electron microscope (SEM) image of FAPbI3-NMP obtained in step 3 of Example 3.

[0061] Figure 4 This is a physical picture of the perovskite wafer obtained in step 4 of Example 4.

[0062] Figure 5 This is a surface SEM image of the perovskite wafer obtained in Example 5.

[0063] Figure 6 This is a surface SEM image of the perovskite wafer obtained after annealing in step five of Example 5.

[0064] Figure 7 This is an IV diagram of the light-dark current contrast of the X-ray detector prepared in Example 6.

[0065] Figure 8 This is the light response diagram of the X-ray detector prepared in Example 6 under a bias voltage of 5V.

[0066] Fig. 9 This is a graph showing the response of the X-ray detector prepared in Example 6 to different doses of X-rays at a bias voltage of 10V. DETAILED DESCRIPTION

[0067] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0068] In the following examples, unless otherwise specified, all reagents and consumables were purchased from conventional reagent manufacturers in the field; unless otherwise specified, the experimental methods and technical means used were conventional methods and means in the field.

[0069] Example 1

[0070] This embodiment provides a method for preparing a perovskite complex, and a method for using the same to prepare a polycrystalline pressed sheet X-ray detector, the specific steps of which are as follows:

[0071] Step 1: Weigh 0.461 g PbI2 and 0.159 g MAI (methyl iodide), dissolve them in DMF (2 mL) to prepare a perovskite precursor solution, then quickly drop the precursor into chloroform (30 mL) at room temperature (25 ° C) and stirring at 800 rpm to precipitate, and obtain perovskite powder after low-temperature vacuum drying (40 ° C);

[0072] Step 2: Mix 50 μL of polar solvent DMSO (dimethyl sulfoxide) and 2 mL of chlorobenzene, add 200 mg of the perovskite powder obtained in step 1, stir at room temperature (500 rpm) and mix until the mixture changes in color and viscosity (time 60 min) and proceed to the next step;

[0073] Step 3: Centrifuge the mixture obtained in step 2 (6000 rpm), discard the solvent (supernatant), and then vacuum dry (40° C.) to obtain MAPbI3-DMSO complex powder, such as Figure 1 As shown, the color of the complex powder changes from the black of perovskite to yellow-green;

[0074] Step 4: Weigh 200 mg of the powder in step 3, select a mold with a size of 1 cm×1 cm, and use a hydraulic press to press it at 80°C and 5 MPa for 10 minutes to press the wafer;

[0075] Step 5: annealing the wafer obtained in step 4 at 100° C. for 2 h;

[0076] Step 6: Use Ag and Cu as two end electrodes (150 nm) to evaporate the wafer respectively without adding a transmission layer, and complete the preparation of the X-ray detector.

[0077] Example 2

[0078] This embodiment provides a method for preparing a perovskite complex, and a method for using the same to prepare a polycrystalline pressed sheet X-ray detector, the specific steps of which are as follows:

[0079] Step 1: Weigh 0.461 g PbI2 and 0.159 g MAI, dissolve them in DMSO (1.5 mL) to prepare a perovskite precursor solution, then quickly drop the precursor into chloroform (30 mL) at room temperature and 600 rpm for precipitation, and obtain perovskite powder after low-temperature vacuum drying (40 ° C);

[0080] Step 2: Mix 60 μL of polar solvent DMF and 2 mL of toluene, add 250 mg of the perovskite powder obtained in step 1, and stir at room temperature (300 rpm) to mix evenly (time 45 min);

[0081] Step 3: Centrifuge the mixture obtained in step 2 (4000 rpm), discard the solvent and dry (35°C) to obtain MAPbI3-DMF complex powder. The XRD signals of perovskite and its complex are as follows: Figure 2 As shown, the diffraction peaks appearing before 2θ = 10° indicate the solvent intercalation in the perovskite lattice;

[0082] Step 4: Weigh 150 mg of the powder in step 3 and 100 mg of the powder in step 1, select a mold with a size of 1 cm×1 cm, and use a hydraulic press to press it at 100°C and 10 MPa for 10 minutes to press the wafer;

[0083] Step 5: annealing the wafer obtained in step 4 at 100° C. for 1 h;

[0084] Step 6: Use Au as the two end electrodes (150 nm) to evaporate the wafer without adding a transmission layer to complete the preparation of the X-ray detector.

[0085] Example 3

[0086] This embodiment provides a method for preparing a perovskite complex, and a method for using the same to prepare a polycrystalline pressed sheet X-ray detector, the specific steps of which are as follows:

[0087] Step 1: Weigh 0.461 g PbI2 and 0.172 g FAI (iodine formamide), dissolve them in DMSO (1.5 mL) to prepare a perovskite precursor solution, then quickly add the above precursor dropwise into toluene (20 mL) under stirring at 600 rpm to precipitate, and obtain perovskite powder after low-temperature vacuum drying (50 ° C);

[0088] Step 2: Mix 40 μL of polar solvent NMP and 2 mL of chloroform, add 150 mg of the perovskite powder obtained in step 1, and stir at room temperature (400 rpm) to mix evenly (60 min);

[0089] Step 3: Centrifuge the mixture obtained in step 2 (4000 rpm), discard the solvent and dry (45°C) to obtain FAPbI3-NMP complex powder, the SEM image of which is as follows: Figure 3 As shown, it exhibits a needle-like morphology;

[0090] Step 4: Weigh 50 mg of the powder in step 3 and 150 mg of the powder in step 1, select a mold with a size of 1 cm×1 cm, and use a hydraulic press to press it at 100°C and 15 MPa for 15 minutes to press the wafer;

[0091] Step 5: annealing the wafer obtained in step 4 at 120° C. for 1 h;

[0092] Step 6: Prepare an X-ray detector with the structure of Cu (150nm) - FAPbI3 chip - PCBM (30nm) - C 60 (60nm)—BCP (10nm)—Ag (150nm).

[0093] Example 4

[0094] This embodiment provides a method for preparing a perovskite complex, and a method for using the same to prepare a polycrystalline pressed sheet X-ray detector, the specific steps of which are as follows:

[0095] Step 1: Weigh 0.367 g PbBr2 and 0.159 g MAI, dissolve them in a mixed solution of DMF (1.8 mL) and DMSO (0.2 mL) to prepare a perovskite precursor solution, then quickly add the above precursor dropwise into toluene (20 mL) under stirring at 600 rpm to precipitate, and obtain perovskite powder after low-temperature vacuum drying (40 ° C);

[0096] Step 2: Mix 30 μL of polar solvent DMSO and 1 mL of chloroform, add 150 mg of the perovskite powder obtained in step 1, and stir at room temperature (400 rpm) to mix evenly (time 30 min);

[0097] Step 3: Centrifuge the mixture obtained in step 2 (4000 rpm), discard the solvent, and then dry (25° C.) to obtain MAPbIBr2-DMSO complex powder;

[0098] Step 4: Weigh 200 mg of the powder in step 3 and 100 mg of the powder in step 1, select a mold with a size of 1.5 cm × 1.5 cm, and use a hydraulic press to press it at 100°C and 10 MPa for 30 minutes to press the wafer. Figure 4 As shown;

[0099] Step 5: annealing the wafer obtained in step 4 at 100° C. for 1 h;

[0100] Step 6: Prepare an X-ray detector with the structure of Cu (150nm)-MAPbIBr2 chip-PCBM (30nm)-C 60 (60nm)—BCP (10nm)—Ag (150nm).

[0101] Example 5

[0102] This embodiment provides a method for preparing a perovskite complex, and a method for using the same to prepare a polycrystalline pressed sheet X-ray detector, the specific steps of which are as follows:

[0103] Step 1: Weigh 0.461 g PbI2 and 0.212 g CsBr raw materials, dissolve them in DMF (2 mL) to prepare a perovskite precursor solution, then quickly drop the precursor into chloroform (20 mL) under stirring at 600 rpm to precipitate, and obtain perovskite powder after low-temperature vacuum drying (40°C);

[0104] Step 2: Mix 30 μL of polar solvent GBL and 2 mL of toluene, add 250 mg of the perovskite powder obtained in step 1, and stir (400 rpm) to mix evenly (time 60 min);

[0105] Step 3: centrifuge the mixture obtained in step 2 (6000 rpm), discard the solvent, and then dry (40° C.) to obtain CsPbI2Br-DBL complex powder;

[0106] Step 4: Weigh 150 mg of the powder prepared in step 3, select a mold with a size of 1 cm × 1 cm, and use a hydraulic press to press it at 150°C and 10 MPa for 30 minutes to press the wafer;

[0107] Step 5: The wafer obtained in step 4 is annealed at 150°C for 1 hour. Figure 5 As shown in the figure, the surface and interface are very dense, and obvious grain fusion can be observed. Figure 6As shown, the thickness is about 500 μm.

[0108] Step six, using Au as the two end electrodes (150 nm) to evaporate the wafer without adding a transmission layer, and completing the preparation of the X-ray detector.

[0109] Example 6

[0110] This embodiment provides a method for preparing a perovskite complex, and a method for using the same to prepare a polycrystalline pressed sheet X-ray detector, the specific steps of which are as follows:

[0111] Step 1: Weigh 0.922 g PbI2, 0.159 g MAI, and 0.172 g FAI raw materials, dissolve them in DMF (3 mL) to prepare a perovskite precursor solution, then quickly add the above precursor dropwise into toluene (50 mL) under stirring at 600 rpm to precipitate, and obtain perovskite powder after low-temperature vacuum drying (40 ° C);

[0112] Step 2: Mix 40 μL of polar DMSO and 2 mL of toluene, add 200 mg of the perovskite powder obtained in step 1, and stir (600 rpm) to mix evenly (time 30 min);

[0113] Step 3: Centrifuge the mixture obtained in step 2 (3000 rpm), discard the solvent, and then dry (30° C.) to obtain MAFAPb2I6-DMSO complex powder;

[0114] Step 4: Weigh 500 mg of the powder in step 3, select a mold with a size of 2 cm × 2 cm, and use a hydraulic press to press it at 100°C and 3 MPa for 20 minutes to press the wafer;

[0115] Step 5: annealing the wafer obtained in step 4 at 100° C. for 2 h;

[0116] Step 6: Use Au as the two end electrodes (150 nm) to evaporate the wafer without adding a transmission layer to complete the preparation of the X-ray detector.

[0117] X-ray response test

[0118] The detectors prepared in each embodiment have good response to X-rays and high light response sensitivity (the results are listed in Table 1). Taking Example 6 as an example, the IV diagram of the light-dark current comparison is shown in FIG. Figure 7 As shown, there is a large switching ratio; the response under 5V bias is as follows Figure 8 As shown in the figure, the response speed is fast and the baseline is stable. The prepared detector responds well to X-rays. Its light response to different doses of X-rays under 10V bias is shown in the figure. Fig. 9As shown, by calculating (the slope of the photocurrent density and X-ray dose rate curve, the sensitivity calculation method is well known in the art and will not be repeated here), the sensitivity can be obtained to be 18080 μC Gy air -1 cm -2 .

[0119] Table 1

[0120] Group <![CDATA[Sensitivity (μC Gy air -1 cm -2 )]]> Example 1 7700 Example 2 6737 Example 3 11235 Example 4 10320 Example 5 12340 Example 6 18080

[0121] In the present invention, if the perovskite powder obtained by step 1 of each embodiment alone cannot be pressed into tablets under the corresponding tableting conditions, even if it is further pressed into tablets, the wafers contain many voids and grain boundaries and cannot be used for the preparation of X-ray detectors. However, by introducing an appropriate amount of polar solvent into the perovskite powder to synthesize the perovskite-solvent complex, the obtained solvent complex has a soft texture and better processing flexibility. A dense and uniform perovskite wafer can be obtained under a relatively small pressure, and the X-ray detector further prepared has high sensitivity. In addition, the perovskite-solvent complex can be mixed with the uncomplexed perovskite powder and then pressed into tablets, and an X-ray detector with higher sensitivity can also be prepared.

[0122] The applicant declares that the present invention uses the above-mentioned embodiments to illustrate the preparation method of a perovskite complex for X-ray detection and its products and applications, but the present invention is not limited to the above-mentioned embodiments, that is, it does not mean that the present invention must rely on the above-mentioned embodiments to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of various raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

[0123] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0124] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

Claims

1. A method for preparing a perovskite complex for X-ray detection, It is characterized in that The preparation method comprises: (1) mixing lead halide, a halogen-containing compound and an organic solvent to obtain a precursor solution, mixing with an anti-solvent to precipitate a reaction product, and drying to obtain perovskite; The lead halide is selected from PbI 2 and / or PbBr 2 ; The halogen-containing compound is selected from any one of MAI, FAI, CsI, MABr, FABr or CsBr, or a combination of at least two thereof; the molar ratio of the lead halide to the halogen-containing compound is (1-2):(1-2); the organic solvent is selected from any one of DMF, DMSO, NMP or GBL, or a combination of at least two thereof; the anti-solvent is selected from any one of chloroform, toluene, isopropanol, acetone, chlorobenzene or ether, or a combination of at least two thereof; the volume ratio of the organic solvent to the anti-solvent is (1-10):(10-200); (2) mixing the perovskite with a solvent to obtain a mixture, and drying the mixture to obtain a perovskite complex; The mass ratio of the perovskite to the solvent in the mixture is 1:(5-20); the mixing temperature is 15-40° C., and the mixing time is 30-120 min; The solvent comprises a polar solvent A and a solvent B; the polar solvent A is selected from any one of DMF, DMSO, NMP or GBL or a combination of at least two thereof; the solvent B is selected from any one of chloroform, toluene, isopropanol, acetone, chlorobenzene or ether or a combination of at least two thereof; the volume ratio of the polar solvent A to the solvent B is (1-10):(100-200).

2. The preparation method according to claim 1, It is characterized in that The mixing in step (2) is carried out under stirring, and the stirring speed is 200-1000rpm.

3. The preparation method according to claim 1, It is characterized in that The drying temperature in step (2) is 20-60°C.

4. The preparation method according to claim 1, It is characterized in that The step (2) further comprises centrifuging the mixture and discarding the supernatant before drying.

5. The preparation method according to claim 4, It is characterized in that The centrifugal speed is 2000-6000 rpm.

6. A method for preparing a perovskite wafer, It is characterized in that The preparation method comprises: preparing a perovskite complex by the preparation method according to any one of claims 1 to 5, and pressing the perovskite complex into tablets; Alternatively, the preparation method comprises: mixing the prepared perovskite complex with perovskite, and pressing the mixture into tablets to obtain the product.

7. The preparation method according to claim 6, It is characterized in that The tableting is carried out under the conditions of 3-20 MPa and 80-150°C.

8. The preparation method according to claim 6, It is characterized in that The tabletting time is 10-40 minutes.

9. The preparation method according to claim 6, It is characterized in that After the tableting, annealing is also included.

10. The preparation method according to claim 9, It is characterized in that The annealing temperature is 80-200° C. and the annealing time is 30-120 min.

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