A flexible heterojunction perovskite detector and its preparation method

Abstract

The present invention discloses a flexible heterojunction perovskite detector and a preparation method thereof, wherein the detector prepares a two-dimensional perovskite material and a three-dimensional perovskite material on both sides of a flexible substrate, respectively, so that the two-dimensional perovskite material and the three-dimensional perovskite material form a heterojunction structure at the interaction, promoting the device to build a built-in electric field, which triggers spontaneous charge separation / transfer. X-ray detectors using heterojunction structures can operate in a self-driven mode and exhibit excellent sensitivity, ultra-low dark current and operational stability. Semiconductors generate photoelectron-hole pairs under radiation conditions, and then the built-in electric field caused by the heterojunction accelerates the separation of photoelectron-hole pairs and the directional movement of photoelectrons. By combining perovskite precursor solutions of different components to construct a built-in electric field structure inside the detector, the charge transfer performance of the device is improved, and 291.82μC·Gy is obtained without the drive of an external electric field. ‑1 cm ‑2 X-ray detection sensitivity.

Description

Technical Field

[0001] The present invention belongs to the technical field of photoelectric detection and relates to a flexible heterojunction perovskite detector and a preparation method thereof. Background Art

[0002] In recent years, perovskite solar cells have attracted significant attention in the photovoltaic solar cell field due to their low cost and rapidly increasing photoelectric conversion efficiency. Currently, further improving the photoelectric conversion efficiency and stability of perovskite solar cells has become a key research topic.

[0003] At the same time, perovskite materials are also widely used in the research of light detectors. People’s understanding of X-rays originated from the great contribution of German researcher W.K. Roentgen in 1895. The wavelength of X-rays ranges from 0.01 nanometers to 10 nanometers, which is between ultraviolet rays and gamma rays, and the corresponding frequency range is from 3×10 16 Hz to 3×10 19 Hz, and the corresponding energy range is 100eV to 100KeV.

[0004] In addition to the general properties of light such as coherent scattering, diffraction and polarization, X-rays also have an important characteristic, namely penetrability, and are widely used in imaging the interior of objects, such as medical imaging (such as CT, i.e., electronic computed tomography) and airport security. X-ray imaging technology has a wide range of important applications in medical diagnosis, security inspections, and industrial non-destructive testing. At the same time, perovskite materials have also stood out in the field of flexible electronic devices due to their advantages such as light weight, low cost, and high chemical compatibility with flexible substrates. In recent years, metal halide perovskite materials have been widely studied for X-ray detection due to their large atomic number, large μτ product, high defect tolerance and low-cost solution processing methods.

[0005] In recent years, flexible wearable electronic devices have gradually emerged in daily life due to their characteristics of light weight, easy integration with the skin, and ability to withstand mechanical deformation. The more common preparation method for perovskite flexible X-ray detectors is to prepare perovskite polycrystalline films on flexible substrates, but simple bending will cause cracks along the grain boundaries of the polycrystalline film, greatly reducing the performance of the device. At the same time, X-ray detectors based on perovskite polycrystalline films usually show quite low sensitivity, because in principle a large active layer thickness of several hundred microns is required to completely attenuate the incident X-rays, which is a thickness that is difficult to achieve in the preparation of polycrystalline films. However, the key cornerstone of wearable electronic devices is good mechanical properties, which require the devices to withstand repeated bending deformations, but the poor mechanical properties of perovskite polycrystalline films obviously cannot meet the needs of flexible devices. Summary of the Invention

[0006] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a flexible heterojunction perovskite detector and a preparation method thereof, so as to solve the problem that the perovskite polycrystalline film in the prior art is difficult to meet the requirements of sensitivity and mechanical properties.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] A flexible heterojunction perovskite detector includes a flexible substrate, one side of the flexible substrate is a two-dimensional perovskite, and the other side is a three-dimensional perovskite; the two-dimensional perovskite and the three-dimensional perovskite interact at the flexible substrate.

[0009] A further improvement of the present invention is:

[0010] Preferably, the flexible substrate is a nylon membrane, a polyethersulfone membrane or a cellulose acetate membrane.

[0011] Preferably, the three-dimensional perovskite is CH3NH3PbI3 (MAPbI3).

[0012] Preferably, the two-dimensional perovskite is (C6H5CH2CH2NH3)2PbI4(PEA2PbI4) or C6N2H 16 PbI4[(3-AMP)PbI4].

[0013] Preferably, the thickness of the flexible heterojunction perovskite detector is 100-120 μm.

[0014] Preferably, the content of two-dimensional perovskite in the three-dimensional perovskite gradually decreases from the flexible substrate to the three-dimensional perovskite surface; and the content of three-dimensional perovskite in the two-dimensional perovskite gradually decreases from the flexible substrate to the two-dimensional perovskite surface.

[0015] A method for preparing a flexible heterojunction perovskite detector comprises the following steps:

[0016] Step 1: Apply a three-dimensional perovskite precursor solution on one side of the flexible substrate, vacuum filter, and then anneal. Repeat the application, vacuum filtration, and annealing process until the three-dimensional perovskite solution on the flexible substrate is saturated.

[0017] Step 2: Applying a two-dimensional perovskite precursor solution on the other side of the flexible substrate, vacuum filtering, and then annealing, repeating the application, vacuum filtering, and annealing process until the other side of the flexible substrate can no longer be filled with the two-dimensional perovskite precursor solution, thereby obtaining a filled film;

[0018] Step 3, heat-pressing the filling film to obtain a hot-pressed filling film;

[0019] Step 4: evaporate metal electrodes on both sides of the hot-pressed filling film to obtain a flexible heterojunction perovskite detector.

[0020] Preferably, in step 1, the concentration of the three-dimensional perovskite solution is 1.8-2.2 M, the solute is PbI2, CH3NH3I (MAI) and CH3NH3Cl (MACl) in a molar ratio of 1:0.90:0.22, and the solvent is ethylene glycol methyl ether (2Me).

[0021] Preferably, in step 2, the concentration of the two-dimensional perovskite solution is 1.2 M, the solutes are PEA2PbI4 and (3-AMP)PbI4, and the solvents are a mixed solution of DMF and DMSO.

[0022] Preferably, in step 3, the hot pressing process is divided into two stages: in the first stage, the heating rate is 1-2°C / min, the hot pressing pressure is 4-6 MPa, the hot pressing time is 10-30 min, and the hot pressing temperature is 40-70°C; in the second stage, the heating rate is 1-2°C / min, the hot pressing pressure is 10-12 MPa, the hot pressing time is 30-50 min, and the hot pressing temperature is 110-150°C.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The present invention discloses a flexible heterojunction perovskite detector, which prepares a two-dimensional perovskite material and a three-dimensional perovskite material on both sides of a flexible substrate, so that the two-dimensional perovskite material and the three-dimensional perovskite material form a heterojunction structure at the interaction, promoting the device to build a built-in electric field, which triggers spontaneous charge separation / transfer. X-ray detectors using heterojunction structures can operate in a self-driven mode and exhibit excellent sensitivity, ultra-low dark current and operational stability. Semiconductors generate photoelectron-hole pairs under radiation conditions, and then the built-in electric field caused by the heterojunction accelerates the separation of photoelectron-hole pairs and the directional movement of photoelectrons. By combining perovskite precursor solutions of different components to construct a built-in electric field structure inside the detector, the charge transfer performance of the device is improved, and 291.82μC·Gy is obtained without the drive of an external electric field. -1 cm -2X-ray detection sensitivity; Unlike previously reported X-ray detectors that require an additional external electric field, the flexible heterojunction detector obtained by the present invention greatly improves the working performance of the perovskite X-ray detector, and its excellent photoelectric performance will help promote the commercial application of perovskite X-ray detectors. At the same time, the main structure of the detector is a flexible substrate, which makes the perovskite more flexible than most existing perovskite X-ray detectors, allowing the perovskite X-ray detector to be used on curved surfaces, expanding the application range of perovskite X-ray detectors. In the present invention, the perovskite material is filled into a porous flexible substrate with good mechanical properties. This solution provides a new solution. The perovskite material guarantees the performance of the device, and the flexible substrate retains the lightness and large-area processability of the device. At the same time, the adjustable thickness of the filling film also solves the problem of incident X-ray attenuation.

[0025] Furthermore, a nylon membrane is selected as the flexible substrate. While the flexibility, toughness and mechanical strength of the nylon membrane meet the requirements of the perovskite detector, the pore structure of the nylon membrane enables the two-dimensional perovskite and the three-dimensional perovskite to penetrate and interact with each other to form a power plant.

[0026] Furthermore, the thickness of the flexible heterojunction perovskite detector is thicker than that of existing perovskite detectors, making its mechanical properties better.

[0027] Furthermore, the content of two-dimensional perovskite in the three-dimensional perovskite changes in a gradient, so that the electric field formed in the entire detector changes gradually, allowing electrons to move spontaneously, which is beneficial to the transmission of charges.

[0028] The present invention also discloses a method for preparing a flexible heterojunction perovskite detector. This method involves filling the upper and lower surfaces of an organic nylon membrane with a two-dimensional perovskite precursor solution and a three-dimensional perovskite precursor solution, respectively. The three-dimensional perovskite solution is first coated on a flexible substrate, and the highly conductive three-dimensional perovskite is first filled into the interior of the porous film in large quantities. The two-dimensional perovskite is then introduced and induced to form a heterojunction within the nylon membrane, thereby establishing a built-in electric field that facilitates spontaneous charge separation or transfer. This method can produce high-quality flexible heterojunction perovskite-filled membranes, thereby obtaining efficient and stable self-powered perovskite X-ray detectors. This will provide a new approach and method for promoting the commercial application of perovskite photodetectors. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 Schematic diagram of the operation flow of the method described in the example of the present invention.

[0030] Figure 2This is a physical picture of a flexible heterojunction perovskite filling film with a diameter of 5 cm prepared by the method described in the example of the present invention, wherein (a) is a physical picture Figure 1 (b) The picture shows the real object Figure 2 .

[0031] Figure 3 This is a cross-sectional morphology diagram of a flexible heterojunction perovskite filling film prepared by the method described in an example of the present invention.

[0032] Figure 4 This graph shows the current variation of a flexible heterojunction perovskite detector fabricated using the method described in this example, without an external power source, under different X-ray doses. (a) shows the detector with a two-dimensional perovskite; (b) shows a pure three-dimensional perovskite.

[0033] Figure 5 This is a current-dose diagram of the flexible heterojunction perovskite detector prepared by the method described in the example of the present invention under different X-ray doses without an external power supply. DETAILED DESCRIPTION

[0034] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments:

[0035] The present invention prepares an X-ray detector by filling the upper and lower surfaces of an organic porous nylon membrane with a three-dimensional perovskite precursor solution and a two-dimensional perovskite precursor solution, respectively. Generally, a high operating bias is necessary for perovskite X-ray detectors to ensure efficient carrier transport and separation. However, the monovalent halogen ions in the perovskite easily migrate under bias, which can cause drift in dark current and signal current. While the use of guard ring electrodes can suppress surface ion migration in three-dimensional perovskite materials, achieving both high sensitivity and low noise, it also increases the complexity of device fabrication and integration. On the other hand, two-dimensional perovskite materials with long chain spacers typically have larger ion migration activation energies, resulting in corresponding detectors exhibiting lower noise. However, the carrier transport properties of two-dimensional perovskites are inferior to those of their three-dimensional counterparts, resulting in relatively low sensitivity. In the present invention, two-dimensional perovskite materials and three-dimensional perovskite materials are introduced on both sides of the porous membrane, forming a heterojunction structure at the junction, which promotes the establishment of a built-in electric field in the device, triggering spontaneous charge separation / transport. Under X-ray excitation, the high-density hot carriers generated throughout the thickness of the heterojunction thick film can be captured and transported through the built-in electromotive force, thereby generating photocurrent. Therefore, the X-ray detector using the heterojunction structure can operate in a self-powered mode and exhibit excellent sensitivity, ultra-low dark current and operational stability. The self-powered perovskite detector does not require an external power supply, which greatly increases convenience while also reducing energy consumption. The process of the present invention is simple, highly operable, and has simple equipment requirements. A built-in electric field is constructed inside the prepared perovskite detector, which greatly improves the charge transfer performance. The flexible heterojunction perovskite prepared by the present invention can have a higher X-ray response rate, and the device also has better stability.

[0036] The present invention provides a method for preparing a flexible heterojunction perovskite detector, such as Figure 1 The specific steps are as follows:

[0037] Step 1, preparing a three-dimensional perovskite solution using ethylene glycol methyl ether (2Me) to prepare a perovskite solution;

[0038] First, a 1.8-2.2 M three-dimensional perovskite precursor solution was prepared in air, in which the molar ratio of solute PbI2, CH3NH3I (MAI) and CH3NH3Cl (MACl) was 1:0.90:0.22;

[0039] Afterwards, 2Me solvent was added, stirred at room temperature for 6 hours, and then filtered through a 0.45 μm pore size polytetrafluoroethylene filter membrane to obtain a clear perovskite solution. The use of 2Me increases the solubility of the solute and produces denser three-dimensional perovskite grains.

[0040] Step 2: Prepare a 1.2M 2D perovskite precursor solution in air. The solutes in solution a are PbI2 and PEAI in a 1:1 molar ratio.

[0041] Afterwards, a solvent with a ratio of DMF:DMSO = 9:1 was added, stirred at 25 °C for 6 h, and then filtered through a polytetrafluoroethylene filter membrane with a pore size of 0.45 μm to obtain a clear PEA2PbI4 perovskite solution with solute a.

[0042] The solute of solution b is (3-AMP)PbI4 powder,

[0043] Afterwards, a solvent with a ratio of DMF:DMSO = 9:1 was added, stirred at 25 °C for 6 h, and then filtered through a polytetrafluoroethylene filter membrane with a pore size of 0.45 μm to obtain a clear (3-AMP)PbI4 perovskite solution with solute b.

[0044] To prepare (3-AMP)PbI4 powder, dissolve 5 mmol of PbO powder in 10 mL of hydroiodic acid and 2 mL of hypophosphorous acid solution, heat at 130°C, and stir for 5-10 minutes until the solution turns clear, bright yellow. Add 5 mL of hydroiodic acid to 5 mmol of 3-AMP in a separate vial and stir. Add the protonated 3-AMP solution to the original solution, heat at 240°C, and stir for 5 minutes. Slowly cool to room temperature to obtain red, flaky crystals of (3-AMP)PbI4.

[0045] Step 3, preparing a clean flexible substrate and a filtration device;

[0046] Select a clean suction filtration bottle, a sand core funnel and a nylon membrane for use; the preferred flexible substrate is a nylon membrane with a diameter of 10 cm and a pore size of 8 μm. The flexible substrate can also be a polyethersulfone (PES) membrane or a cellulose acetate membrane.

[0047] Step 4, filling the three-dimensional perovskite solution;

[0048] The three-dimensional perovskite precursor solution (PEA2PbI4 perovskite solution or (3-AMP)PbI4 perovskite solution) is evenly coated on a clean nylon membrane; the vacuum pump is turned on for filtration, and when no liquid drips, it is transferred to a hot plate for annealing for 2 hours, and repeated multiple times until the nylon membrane can no longer be filled; when filling the three-dimensional solution, the vacuum pump maintains a vacuum degree of 0.3Mpa, the annealing temperature is 70-100°C, and the time is two hours.

[0049] Step 5, filling the two-dimensional perovskite solution;

[0050] The 2D perovskite precursor solution was evenly coated onto the nylon membrane surface that was not filled with the 3D solution. A vacuum pump was activated for filtration. When no more liquid dripped, the membrane was transferred to a hot plate for annealing for two hours. While filling with the 2D solution, the vacuum pump maintained a vacuum of 0.3 MPa, and the annealing temperature was set at 120°C for two hours.

[0051] Step 6, hot pressing the filling film;

[0052] The annealed perovskite filling film is cooled to room temperature, and the annealed perovskite filling film is cooled to room temperature using a hot press. The temperature is raised to 40-70°C at a rate of 1-2°C / minute at 4-6 MPa and kept warm for 10-30 minutes, and then raised to 110-150°C at a rate of 1-2°C / minute at 10-12 MPa and kept warm for 30-50 minutes. Finally, the filling film is removed when the hot press cools to room temperature. Two-stage hot pressing can make the perovskite grains melt more fully and then recrystallize, growing larger grains, which is conducive to charge transfer.

[0053] Step 7: vapor-deposit gold electrodes on both sides of the prepared perovskite filling film to obtain a perovskite X-ray detector device. The vapor-deposited thickness of the gold electrodes is 100-120 nm, forming upper and lower electrodes.

[0054] The flexible heterojunction perovskite detector fabricated using this method features a flexible substrate in the middle, with a two-dimensional perovskite on one side and a three-dimensional perovskite on the other. The two-dimensional and three-dimensional perovskites interact with each other on the flexible substrate, and the two-dimensional and three-dimensional perovskites have a gradient content. The three-dimensional perovskite is CH₃NH₃PbI₃, while the two-dimensional perovskites are PEA₂PbI₄ and (3-AMP)PbI₄, respectively. The resulting flexible heterojunction perovskite detector has a thickness of 100 to 120 μm.

[0055] Photoelectric detection tests were conducted at room temperature using a Keysight 2912B precision measurement source meter with a tungsten anode target X-ray source as the excitation source. The tungsten anode target X-ray source had a peak energy of 40 keV and an average energy of 29 keV.

[0056] Example 1

[0057] Step 1: Prepare a 3D perovskite precursor solution with a concentration of 2.2 M, a solute ratio of PbI₂:MAI:MACl = 1:0.90:0.22, and a solvent of 2Me. Stir at 25°C for 6 hours, then filter through a 0.45 μm pore size polytetrafluoroethylene filter to obtain a clear perovskite solution.

[0058] Step 2: Prepare a PEA2PbI4 perovskite precursor solution; prepare a two-dimensional PEA2PbI4 precursor solution with a concentration of 1.2 M and a solute to solvent ratio of PbI2:PEAI = 1:1 and DMSO:DMF = 9:1, respectively. Stir at 25°C for 6 hours, and then filter through a 0.45 μm pore size polytetrafluoroethylene filter membrane to obtain a clear perovskite solution.

[0059] Prepare a (3-AMP)PbI4 perovskite precursor solution; prepare a two-dimensional (3-AMP)PbI4 precursor solution with a concentration of 1.2M, a solute of (3-AMP)PbI4 powder, a solvent ratio of DMSO:DMF=9:1, stir at 25°C for 6h, and then filter with a polytetrafluoroethylene filter membrane with a pore size of 0.45μm to obtain a clear perovskite solution.

[0060] Step 3, prepare a clean nylon membrane and filtration device;

[0061] Select a clean suction filtration bottle, sand core funnel and nylon membrane for use.

[0062] Step 4, filling the three-dimensional perovskite solution;

[0063] The three-dimensional perovskite precursor solution is evenly coated on a clean nylon membrane; a vacuum pump is turned on for filtration, and when no liquid drips, the solution is transferred to a 100°C hot plate for annealing for 2 hours. This process is repeated several times until the nylon membrane can no longer be filled.

[0064] Step 5, filling the two-dimensional perovskite solution;

[0065] The two-dimensional perovskite precursor solution was evenly coated on the nylon membrane surface that was not filled with the three-dimensional solution; the vacuum pump was turned on for filtration, and when no liquid dripped, it was transferred to a 130°C hot plate for annealing for 2 hours.

[0066] Step 6, hot pressing the filling film;

[0067] The annealed perovskite filling film was cooled to room temperature, and the annealed perovskite filling film was cooled to room temperature using a hot press. The temperature was raised to 40°C at a rate of 1°C / min at 4 MPa and kept warm for 10 minutes, and then the temperature was raised to 150°C at a rate of 1°C / min at 10 MPa and kept warm for 30 minutes. Finally, the filling film was removed when the hot press cooled to room temperature.

[0068] Step 7: Vapor-deposit a gold electrode on the prepared perovskite filling film to obtain a perovskite X-ray detector device.

[0069] See also Figure 2 This is a physical picture of a flexible heterojunction perovskite filling film with a diameter of 5 cm prepared by the method described in this example. It can be seen from the figure that the filling film prepared by this method has a bright and smooth surface and good flexibility.

[0070] See also Figure 3 This is a cross-sectional topography of the flexible heterojunction perovskite detector fabricated using the method described in this example. Grains up to 10 μm in size can be observed, and the pores of the nylon membrane are compactly filled with perovskite crystals, which ensures charge transport throughout the membrane. Rough boundaries between the MAPbI3 perovskite grains and the two-dimensional perovskite grains are observed in the vertical direction.

[0071] See also Figure 4 Figure 2 shows the current variation of the flexible heterojunction perovskite detector fabricated using the method described in this example under different X-ray doses without an external power supply. As can be seen from the figure, the detector with a two-dimensional perovskite-filled heterojunction film (Figure (a)) exhibits a current signal response to X-ray irradiation at a bias voltage of 0V. In contrast, the detector with a pure three-dimensional perovskite-filled film exhibits no current signal response to X-ray irradiation at a bias voltage of 0V, as shown in Figure (b).

[0072] See also Figure 5 The current-dose diagram of the flexible heterojunction perovskite detector prepared by the method described in this example under different X-ray doses without an external power supply is shown, and the sensitivity of the flexible heterojunction perovskite detector prepared by the method described in the invention example is calculated. It can be found that the heterojunction filled film detector introduced with PEA2PbI4 and (3-AMP)PbI4 exhibits 291.8μC Gy in the self-powered mode (without external bias). air -1 cm -2 and 83.8 μC Gy air -1 cm -2 The considerable sensitivity of commercial α-Se (20μC Gy air -1 cm -2 ) is 14 and 4 times as much.

[0073] Example 2

[0074] Step 1: Prepare a 3D perovskite precursor solution with a concentration of 1.8 M, a solute ratio of PbI₂:MAI:MACl = 1:0.90:0.22, and a solvent of 2Me. Stir at 25°C for 6 hours, then filter through a 0.45 μm pore size polytetrafluoroethylene filter to obtain a clear perovskite solution.

[0075] Step 2: Prepare a PEA2PbI4 perovskite precursor solution; prepare a two-dimensional PEA2PbI4 precursor solution with a concentration of 1.2 M and a solute to solvent ratio of PbI2:PEAI = 1:1 and DMSO:DMF = 9:1, respectively. Stir at 25°C for 6 hours, and then filter through a 0.45 μm pore size polytetrafluoroethylene filter membrane to obtain a clear perovskite solution.

[0076] Prepare a (3-AMP)PbI4 perovskite precursor solution; prepare a two-dimensional (3-AMP)PbI4 precursor solution with a concentration of 1.2M, a solute of (3-AMP)PbI4 powder, a solvent ratio of DMSO:DMF=9:1, stir at 25°C for 6h, and then filter with a polytetrafluoroethylene filter membrane with a pore size of 0.45μm to obtain a clear perovskite solution.

[0077] Step 3, prepare a clean nylon membrane and filtration device;

[0078] Select a clean suction filtration bottle, sand core funnel and nylon membrane for use.

[0079] Step 4, filling the three-dimensional perovskite solution;

[0080] The three-dimensional perovskite precursor solution is evenly coated on a clean nylon membrane; a vacuum pump is turned on for filtration, and when no liquid drips, the solution is transferred to a 100°C hot plate for annealing for 2 hours. This process is repeated several times until the nylon membrane can no longer be filled.

[0081] Step 5, filling the two-dimensional perovskite solution;

[0082] The two-dimensional perovskite precursor solution was evenly coated on the nylon membrane surface that was not filled with the three-dimensional solution; the vacuum pump was turned on for filtration, and when no liquid dripped, it was transferred to a 130°C hot plate for annealing for 2 hours.

[0083] Step 6, hot pressing the filling film;

[0084] The annealed perovskite filling film was cooled to room temperature, and the annealed perovskite filling film was cooled to room temperature using a hot press. The temperature was raised to 40°C at a rate of 1°C / min at 4 MPa and kept warm for 10 minutes, and then the temperature was raised to 150°C at a rate of 1°C / min at 10 MPa and kept warm for 30 minutes. Finally, the filling film was removed when the hot press cooled to room temperature.

[0085] Step 7: Vapor-deposit a gold electrode on the prepared perovskite filling film to obtain a perovskite X-ray detector device.

[0086] Example 3

[0087] Step 1: Prepare a 3D perovskite precursor solution with a concentration of 2.2 M, a solute ratio of PbI₂:MAI:MACl = 1:0.90:0.22, and a solvent of 2Me. Stir at 25°C for 6 hours, then filter through a 0.45 μm pore size polytetrafluoroethylene filter to obtain a clear perovskite solution.

[0088] Step 2: Prepare a PEA2PbI4 perovskite precursor solution; prepare a two-dimensional PEA2PbI4 precursor solution with a concentration of 1.2 M and a solute to solvent ratio of PbI2:PEAI = 1:1 and DMSO:DMF = 9:1, respectively. Stir at 25°C for 6 hours, and then filter through a 0.45 μm pore size polytetrafluoroethylene filter membrane to obtain a clear perovskite solution.

[0089] Prepare a (3-AMP)PbI4 perovskite precursor solution; prepare a two-dimensional (3-AMP)PbI4 precursor solution with a concentration of 1.2M, a solute of (3-AMP)PbI4 powder, a solvent ratio of DMSO:DMF=9:1, stir at 25°C for 6h, and then filter with a polytetrafluoroethylene filter membrane with a pore size of 0.45μm to obtain a clear perovskite solution.

[0090] Step 3, prepare a clean nylon membrane and filtration device;

[0091] Select a clean suction filtration bottle, sand core funnel and nylon membrane for use.

[0092] Step 4, filling the three-dimensional perovskite solution;

[0093] The three-dimensional perovskite precursor solution is evenly coated on a clean nylon membrane; a vacuum pump is turned on for filtration, and when no liquid drips, the solution is transferred to a 70°C hot plate for annealing for 2 hours, and the process is repeated several times until the nylon membrane can no longer be filled;

[0094] Step 5, filling the two-dimensional perovskite solution;

[0095] The two-dimensional perovskite precursor solution was evenly coated on the nylon membrane surface that was not filled with the three-dimensional solution; the vacuum pump was turned on for filtration, and when no liquid dripped, it was transferred to a 130°C hot plate for annealing for 2 hours.

[0096] Step 6, hot pressing the filling film;

[0097] The annealed perovskite filling film was cooled to room temperature, and the annealed perovskite filling film was cooled to room temperature using a hot press. The temperature was raised to 40°C at a rate of 1°C / min at 4 MPa and kept warm for 10 minutes, and then the temperature was raised to 110°C at a rate of 1°C / min at 10 MPa and kept warm for 30 minutes. Finally, the filling film was removed when the hot press cooled to room temperature.

[0098] Step 7: Vapor-deposit a gold electrode on the prepared perovskite filling film to obtain a perovskite X-ray detector device.

[0099] Example 4

[0100] Step 1: Prepare a 3D perovskite precursor solution with a concentration of 2.2 M, a solute ratio of PbI₂:MAI:MACl = 1:0.90:0.22, and a solvent of 2Me. Stir at 25°C for 6 hours, then filter through a 0.45 μm pore size polytetrafluoroethylene filter to obtain a clear perovskite solution.

[0101] Step 2: Prepare a PEA2PbI4 perovskite precursor solution; prepare a two-dimensional PEA2PbI4 precursor solution with a concentration of 1.2 M and a solute to solvent ratio of PbI2:PEAI = 1:1 and DMSO:DMF = 9:1, respectively. Stir at 25°C for 6 hours, and then filter through a 0.45 μm pore size polytetrafluoroethylene filter membrane to obtain a clear perovskite solution.

[0102] Prepare a (3-AMP)PbI4 perovskite precursor solution; prepare a two-dimensional (3-AMP)PbI4 precursor solution with a concentration of 1.2M, a solute of (3-AMP)PbI4 powder, a solvent ratio of DMSO:DMF=9:1, stir at 25°C for 6h, and then filter with a polytetrafluoroethylene filter membrane with a pore size of 0.45μm to obtain a clear perovskite solution.

[0103] Step 3, prepare a clean nylon membrane and filtration device;

[0104] Select a clean suction filtration bottle, sand core funnel and nylon membrane for use.

[0105] Step 4, filling the three-dimensional perovskite solution;

[0106] The three-dimensional perovskite precursor solution is evenly coated on a clean nylon membrane; a vacuum pump is turned on for filtration, and when no liquid drips, the solution is transferred to a 100°C hot plate for annealing for 2 hours. This process is repeated several times until the nylon membrane can no longer be filled.

[0107] Step 5, filling the two-dimensional perovskite solution;

[0108] The two-dimensional perovskite precursor solution was evenly coated on the nylon membrane surface that was not filled with the three-dimensional solution; the vacuum pump was turned on for filtration, and when no liquid dripped, it was transferred to a 110°C hot plate for annealing for 2 hours.

[0109] Step 6, hot pressing the filling film;

[0110] The annealed perovskite filling film was cooled to room temperature, and the annealed perovskite filling film was cooled to room temperature using a hot press. The temperature was raised to 40°C at a rate of 1°C / min at 4 MPa and kept warm for 10 minutes, and then the temperature was raised to 150°C at a rate of 1°C / min at 10 MPa and kept warm for 30 minutes. Finally, the filling film was removed when the hot press cooled to room temperature.

[0111] Step 7: Vapor-deposit a gold electrode on the prepared perovskite filling film to obtain a perovskite X-ray detector device.

[0112] Example 5

[0113] Step 1: Prepare a 3D perovskite precursor solution with a concentration of 2.2 M, a solute ratio of PbI₂:MAI:MACl = 1:0.90:0.22, and a solvent of 2Me. Stir at 25°C for 6 hours, then filter through a 0.45 μm pore size polytetrafluoroethylene filter to obtain a clear perovskite solution.

[0114] Step 2: Prepare a PEA2PbI4 perovskite precursor solution; prepare a two-dimensional PEA2PbI4 precursor solution with a concentration of 1.2 M and a solute to solvent ratio of PbI2:PEAI = 1:1 and DMSO:DMF = 9:1, respectively. Stir at 25°C for 6 hours, and then filter through a 0.45 μm pore size polytetrafluoroethylene filter membrane to obtain a clear perovskite solution.

[0115] Prepare a (3-AMP)PbI4 perovskite precursor solution; prepare a two-dimensional (3-AMP)PbI4 precursor solution with a concentration of 1.2M, a solute of (3-AMP)PbI4 powder, a solvent ratio of DMSO:DMF=9:1, stir at 25°C for 6h, and then filter with a polytetrafluoroethylene filter membrane with a pore size of 0.45μm to obtain a clear perovskite solution.

[0116] Step 3, prepare a clean nylon membrane and filtration device;

[0117] Select a clean suction filtration bottle, sand core funnel and nylon membrane for use.

[0118] Step 4, filling the three-dimensional perovskite solution;

[0119] The three-dimensional perovskite precursor solution is evenly coated on a clean nylon membrane; a vacuum pump is turned on for filtration, and when no liquid drips, the solution is transferred to a 100°C hot plate for annealing for 2 hours. This process is repeated several times until the nylon membrane can no longer be filled.

[0120] Step 5, filling the two-dimensional perovskite solution;

[0121] The two-dimensional perovskite precursor solution was evenly coated on the nylon membrane surface that was not filled with the three-dimensional solution; the vacuum pump was turned on for filtration, and when no liquid dripped, it was transferred to a 130°C hot plate for annealing for 2 hours.

[0122] Step 6, hot pressing the filling film;

[0123] The annealed perovskite filling film was cooled to room temperature, and the annealed perovskite filling film was cooled to room temperature using a hot press. The temperature was raised to 40°C at a rate of 1°C / min at 6 MPa and kept warm for 10 minutes, and then the temperature was raised to 150°C at a rate of 1°C / min at 10 MPa and kept warm for 30 minutes. Finally, the filling film was removed when the hot press cooled to room temperature.

[0124] Step 7: Vapor-deposit a gold electrode on the prepared perovskite filling film to obtain a perovskite X-ray detector device.

[0125] Example 6

[0126] Step 1: Prepare a 3D perovskite precursor solution; prepare a 2M MAPbI3 perovskite precursor solution with a solute ratio of PbI2:MAI:MACl = 1:0.90:0.22, and a 2Me solvent. Stir at 25°C for 6 hours, then filter through a 0.45μm pore size polytetrafluoroethylene filter to obtain a clear perovskite solution.

[0127] Step 2: Prepare a PEA2PbI4 perovskite precursor solution; prepare a two-dimensional PEA2PbI4 precursor solution with a concentration of 1.2 M and a solute to solvent ratio of PbI2:PEAI = 1:1 and DMSO:DMF = 9:1, respectively. Stir at 25°C for 6 hours, and then filter through a 0.45 μm pore size polytetrafluoroethylene filter membrane to obtain a clear perovskite solution.

[0128] Prepare a (3-AMP)PbI4 perovskite precursor solution; prepare a two-dimensional (3-AMP)PbI4 precursor solution with a concentration of 1.2M, a solute of (3-AMP)PbI4 powder, a solvent ratio of DMSO:DMF=9:1, stir at 25°C for 6h, and then filter with a polytetrafluoroethylene filter membrane with a pore size of 0.45μm to obtain a clear perovskite solution.

[0129] Step 3, prepare a clean nylon membrane and filtration device;

[0130] Select a clean suction filtration bottle, sand core funnel and nylon membrane for use.

[0131] Step 4, filling the three-dimensional perovskite solution;

[0132] The three-dimensional perovskite precursor solution is evenly coated on a clean nylon membrane; a vacuum pump is turned on for filtration, and when no liquid drips, the solution is transferred to an 80°C hot plate for annealing for 2 hours, and the process is repeated several times until the nylon membrane can no longer be filled;

[0133] Step 5, filling the two-dimensional perovskite solution;

[0134] The two-dimensional perovskite precursor solution was evenly coated on the nylon membrane surface that was not filled with the three-dimensional solution; the vacuum pump was turned on for filtration, and when no liquid dripped, it was transferred to a 130°C hot plate for annealing for 2 hours.

[0135] Step 6, hot pressing the filling film;

[0136] The annealed perovskite filling film was cooled to room temperature, and the annealed perovskite filling film was cooled to room temperature using a hot press. The temperature was raised to 60°C at a rate of 2°C / min at 4 MPa and kept warm for 20 minutes, and then raised to 130°C at a rate of 2°C / min at 10 MPa and kept warm for 40 minutes. Finally, the filling film was removed when the hot press cooled to room temperature.

[0137] Step 7: Vapor-deposit a gold electrode on the prepared perovskite filling film to obtain a perovskite X-ray detector device.

[0138] Example 7

[0139] Step 1: Prepare a 3D perovskite precursor solution with a concentration of 2.2 M, a solute ratio of PbI₂:MAI:MACl = 1:0.90:0.22, and a solvent of 2Me. Stir at 25°C for 6 hours, then filter through a 0.45 μm pore size polytetrafluoroethylene filter to obtain a clear perovskite solution.

[0140] Step 2: Prepare a PEA2PbI4 perovskite precursor solution; prepare a two-dimensional PEA2PbI4 precursor solution with a concentration of 1.2 M and a solute to solvent ratio of PbI2:PEAI = 1:1 and DMSO:DMF = 9:1, respectively. Stir at 25°C for 6 hours, and then filter through a 0.45 μm pore size polytetrafluoroethylene filter membrane to obtain a clear perovskite solution.

[0141] Prepare a (3-AMP)PbI4 perovskite precursor solution; prepare a two-dimensional (3-AMP)PbI4 precursor solution with a concentration of 1.2M, a solute of (3-AMP)PbI4 powder, a solvent ratio of DMSO:DMF=9:1, stir at 25°C for 6h, and then filter with a polytetrafluoroethylene filter membrane with a pore size of 0.45μm to obtain a clear perovskite solution.

[0142] Step 3, prepare a clean nylon membrane and filtration device;

[0143] Select a clean suction filtration bottle, sand core funnel and nylon membrane for use.

[0144] Step 4, filling the three-dimensional perovskite solution;

[0145] The three-dimensional perovskite precursor solution is evenly coated on a clean nylon membrane; a vacuum pump is turned on for filtration, and when no liquid drips, the solution is transferred to a 100°C hot plate for annealing for 2 hours. This process is repeated several times until the nylon membrane can no longer be filled.

[0146] Step 5, filling the two-dimensional perovskite solution;

[0147] The two-dimensional perovskite precursor solution was evenly coated on the nylon membrane surface that was not filled with the three-dimensional solution; the vacuum pump was turned on for filtration, and when no liquid dripped, it was transferred to a 130°C hot plate for annealing for 2 hours.

[0148] Step 6, hot pressing the filling film;

[0149] The annealed perovskite filling film was cooled to room temperature, and the annealed perovskite filling film was cooled to room temperature using a hot press. The temperature was raised to 70°C at a rate of 1°C / min at 4 MPa and kept warm for 10 minutes, and then the temperature was raised to 150°C at a rate of 1°C / min at 10 MPa and kept warm for 40 minutes. Finally, the filling film was removed when the hot press cooled to room temperature.

[0150] Step 7: Vapor-deposit a gold electrode on the prepared perovskite filling film to obtain a perovskite X-ray detector device.

[0151] Example 8

[0152] Step 1: Prepare a 3D perovskite precursor solution with a concentration of 1.9 M, a solute ratio of PbI₂:MAI:MACl = 1:0.90:0.22, and a solvent of 2Me. Stir at 25°C for 6 hours, then filter through a 0.45 μm pore size polytetrafluoroethylene filter to obtain a clear perovskite solution.

[0153] Step 2: Prepare a PEA2PbI4 perovskite precursor solution; prepare a two-dimensional PEA2PbI4 precursor solution with a concentration of 1.2 M and a solute to solvent ratio of PbI2:PEAI = 1:1 and DMSO:DMF = 9:1, respectively. Stir at 25°C for 6 hours, and then filter through a 0.45 μm pore size polytetrafluoroethylene filter membrane to obtain a clear perovskite solution.

[0154] Prepare a (3-AMP)PbI4 perovskite precursor solution; prepare a two-dimensional (3-AMP)PbI4 precursor solution with a concentration of 1.2M, a solute of (3-AMP)PbI4 powder, a solvent ratio of DMSO:DMF=9:1, stir at 25°C for 6h, and then filter with a polytetrafluoroethylene filter membrane with a pore size of 0.45μm to obtain a clear perovskite solution.

[0155] Step 3, prepare a clean nylon membrane and filtration device;

[0156] Select a clean suction filtration bottle, sand core funnel and nylon membrane for use.

[0157] Step 4, filling the three-dimensional perovskite solution;

[0158] The three-dimensional perovskite precursor solution is evenly coated on a clean nylon membrane; a vacuum pump is turned on for filtration, and when no liquid drips, the solution is transferred to a 90°C hot plate for annealing for 2 hours, and the process is repeated several times until the nylon membrane can no longer be filled;

[0159] Step 5, filling the two-dimensional perovskite solution;

[0160] The two-dimensional perovskite precursor solution was evenly coated on the nylon membrane surface that was not filled with the three-dimensional solution; the vacuum pump was turned on for filtration, and when no liquid dripped, it was transferred to a 130°C hot plate for annealing for 2 hours.

[0161] Step 6, hot pressing the filling film;

[0162] The annealed perovskite filling film was cooled to room temperature, and the annealed perovskite filling film was cooled to room temperature using a hot press. The temperature was raised to 40°C at a rate of 1°C / min at 5 MPa and kept warm for 30 minutes, and then the temperature was raised to 140°C at a rate of 1°C / min at 11 MPa and kept warm for 30 minutes. Finally, the filling film was removed when the hot press cooled to room temperature.

[0163] Step 7: Vapor-deposit a gold electrode on the prepared perovskite filling film to obtain a perovskite X-ray detector device.

[0164] Example 9

[0165] Step 1: Prepare a 3D perovskite precursor solution with a concentration of 2.2 M, a solute ratio of PbI₂:MAI:MACl = 1:0.90:0.22, and a solvent of 2Me. Stir at 25°C for 6 hours, then filter through a 0.45 μm pore size polytetrafluoroethylene filter to obtain a clear perovskite solution.

[0166] Step 2: Prepare a PEA2PbI4 perovskite precursor solution; prepare a two-dimensional PEA2PbI4 precursor solution with a concentration of 1.2 M and a solute to solvent ratio of PbI2:PEAI = 1:1 and DMSO:DMF = 9:1, respectively. Stir at 25°C for 6 hours, and then filter through a 0.45 μm pore size polytetrafluoroethylene filter membrane to obtain a clear perovskite solution.

[0167] Prepare a (3-AMP)PbI4 perovskite precursor solution; prepare a two-dimensional (3-AMP)PbI4 precursor solution with a concentration of 1.2M, a solute of (3-AMP)PbI4 powder, a solvent ratio of DMSO:DMF=9:1, stir at 25°C for 6h, and then filter with a polytetrafluoroethylene filter membrane with a pore size of 0.45μm to obtain a clear perovskite solution.

[0168] Step 3, prepare a clean nylon membrane and filtration device;

[0169] Select a clean suction filtration bottle, sand core funnel and nylon membrane for use.

[0170] Step 4, filling the three-dimensional perovskite solution;

[0171] The three-dimensional perovskite precursor solution is evenly coated on a clean nylon membrane; a vacuum pump is turned on for filtration, and when no liquid drips, the solution is transferred to a 100°C hot plate for annealing for 2 hours. This process is repeated several times until the nylon membrane can no longer be filled.

[0172] Step 5, filling the two-dimensional perovskite solution;

[0173] The two-dimensional perovskite precursor solution was evenly coated on the nylon membrane surface that was not filled with the three-dimensional solution; the vacuum pump was turned on for filtration, and when no liquid dripped, it was transferred to a 130°C hot plate for annealing for 2 hours.

[0174] Step 6, hot pressing the filling film;

[0175] The annealed perovskite filling film was cooled to room temperature, and the annealed perovskite filling film was cooled to room temperature using a hot press. The temperature was raised to 40°C at a rate of 1°C / min at 4 MPa and kept warm for 20 minutes, and then the temperature was raised to 150°C at a rate of 1°C / min at 12 MPa and kept warm for 30 minutes. Finally, the filling film was removed when the hot press cooled to room temperature.

[0176] Step 7: Vapor-deposit a gold electrode on the prepared perovskite filling film to obtain a perovskite X-ray detector device.

[0177] Example 10

[0178] Step 1: Prepare a 3D perovskite precursor solution with a concentration of 2.2 M, a solute ratio of PbI₂:MAI:MACl = 1:0.90:0.22, and a solvent of 2Me. Stir at 25°C for 6 hours, then filter through a 0.45 μm pore size polytetrafluoroethylene filter to obtain a clear perovskite solution.

[0179] Step 2: Prepare a PEA2PbI4 perovskite precursor solution; prepare a two-dimensional PEA2PbI4 precursor solution with a concentration of 1.2 M and a solute to solvent ratio of PbI2:PEAI = 1:1 and DMSO:DMF = 9:1, respectively. Stir at 25°C for 6 hours, and then filter through a 0.45 μm pore size polytetrafluoroethylene filter membrane to obtain a clear perovskite solution.

[0180] Prepare a (3-AMP)PbI4 perovskite precursor solution; prepare a two-dimensional (3-AMP)PbI4 precursor solution with a concentration of 1.2M, a solute of (3-AMP)PbI4 powder, a solvent ratio of DMSO:DMF=9:1, stir at 25°C for 6h, and then filter with a polytetrafluoroethylene filter membrane with a pore size of 0.45μm to obtain a clear perovskite solution.

[0181] Step 3, prepare a clean nylon membrane and filtration device;

[0182] Select a clean suction filtration bottle, sand core funnel and nylon membrane for use.

[0183] Step 4, filling the three-dimensional perovskite solution;

[0184] The three-dimensional perovskite precursor solution is evenly coated on a clean nylon membrane; a vacuum pump is turned on for filtration, and when no liquid drips, the solution is transferred to a 100°C hot plate for annealing for 2 hours. This process is repeated several times until the nylon membrane can no longer be filled.

[0185] Step 5, filling the two-dimensional perovskite solution;

[0186] The two-dimensional perovskite precursor solution was evenly coated on the nylon membrane surface that was not filled with the three-dimensional solution; the vacuum pump was turned on for filtration, and when no liquid dripped, it was transferred to a 130°C hot plate for annealing for 2 hours.

[0187] Step 6, hot pressing the filling film;

[0188] The annealed perovskite filling film was cooled to room temperature, and the annealed perovskite filling film was cooled to room temperature using a hot press. The temperature was raised to 40°C at a rate of 1°C / min at 4 MPa and kept warm for 10 minutes, and then raised to 120°C at a rate of 1°C / min at 10 MPa and kept warm for 30 minutes. Finally, the filling film was removed when the hot press cooled to room temperature.

[0189] Step 7: Vapor-deposit a gold electrode on the prepared perovskite filling film to obtain a perovskite X-ray detector device.

[0190] Example 11

[0191] Step 1: Prepare a 3D perovskite precursor solution with a concentration of 2.2 M, a solute ratio of PbI₂:MAI:MACl = 1:0.90:0.22, and a solvent of 2Me. Stir at 25°C for 6 hours, then filter through a 0.45 μm pore size polytetrafluoroethylene filter to obtain a clear perovskite solution.

[0192] Step 2: Prepare a PEA2PbI4 perovskite precursor solution; prepare a two-dimensional PEA2PbI4 precursor solution with a concentration of 1.2 M and a solute to solvent ratio of PbI2:PEAI = 1:1 and DMSO:DMF = 9:1, respectively. Stir at 25°C for 6 hours, and then filter through a 0.45 μm pore size polytetrafluoroethylene filter membrane to obtain a clear perovskite solution.

[0193] Prepare a (3-AMP)PbI4 perovskite precursor solution; prepare a two-dimensional (3-AMP)PbI4 precursor solution with a concentration of 1.2M, a solute of (3-AMP)PbI4 powder, a solvent ratio of DMSO:DMF=9:1, stir at 25°C for 6h, and then filter with a polytetrafluoroethylene filter membrane with a pore size of 0.45μm to obtain a clear perovskite solution.

[0194] Step 3, prepare a clean nylon membrane and filtration device;

[0195] Select a clean suction filtration bottle, sand core funnel and nylon membrane for use.

[0196] Step 4, filling the three-dimensional perovskite solution;

[0197] The three-dimensional perovskite precursor solution is evenly coated on a clean nylon membrane; a vacuum pump is turned on for filtration, and when no liquid drips, the solution is transferred to a 100°C hot plate for annealing for 2 hours. This process is repeated several times until the nylon membrane can no longer be filled.

[0198] Step 5, filling the two-dimensional perovskite solution;

[0199] The two-dimensional perovskite precursor solution was evenly coated on the nylon membrane surface that was not filled with the three-dimensional solution; the vacuum pump was turned on for filtration, and when no liquid dripped, it was transferred to a 130°C hot plate for annealing for 2 hours.

[0200] Step 6, hot pressing the filling film;

[0201] The annealed perovskite filling film was cooled to room temperature, and the annealed perovskite filling film was cooled to room temperature using a hot press. The temperature was raised to 40°C at a rate of 1°C / min at 4 MPa and kept warm for 10 minutes, and then the temperature was raised to 150°C at a rate of 1°C / min at 10 MPa and kept warm for 50 minutes. Finally, the filling film was removed when the hot press cooled to room temperature.

[0202] Step 7: Vapor-deposit a gold electrode on the prepared perovskite filling film to obtain a perovskite X-ray detector device.

[0203] Example 12

[0204] The nylon membrane in this example is replaced by a polyethersulfone membrane, and the remaining parameters are the same as those in Example 11.

[0205] Example 13

[0206] The nylon membrane in this embodiment is replaced by a cellulose acetate membrane, and the remaining parameters are the same as those in Example 11.

[0207] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A flexible heterojunction perovskite detector, characterized in that: The invention comprises a flexible substrate, wherein one side of the flexible substrate is a two-dimensional perovskite and the other side is a three-dimensional perovskite; the two-dimensional perovskite and the three-dimensional perovskite interact at the flexible substrate; The three-dimensional perovskite is CH3NH3PbI3 (MAPbI3); The two-dimensional perovskite is (C6H5CH2CH2NH3)2PbI4 (PEA2PbI4) or C6N2H 16 PbI4[(3-AMP)PbI4]; The method for preparing the flexible heterojunction perovskite detector comprises the following steps: Step 1: Apply a three-dimensional perovskite precursor solution on one side of the flexible substrate, vacuum filter, and then anneal. Repeat the application, vacuum filtration, and annealing process until the three-dimensional perovskite solution on the flexible substrate is saturated. Step 2: Applying a two-dimensional perovskite precursor solution on the other side of the flexible substrate, vacuum filtering, and then annealing, repeating the application, vacuum filtering, and annealing process until the other side of the flexible substrate can no longer be filled with the two-dimensional perovskite precursor solution, thereby obtaining a filled film; Step 3, heat-pressing the filling film to obtain a hot-pressed filling film; Step 4: evaporate metal electrodes on both sides of the hot-pressed filling film to obtain a flexible heterojunction perovskite detector.

2. The flexible heterojunction perovskite detector according to claim 1, characterized in that: The flexible substrate is a nylon film, a polyethersulfone film or a cellulose acetate film.

3. The flexible heterojunction perovskite detector according to claim 1, characterized in that: The thickness of the flexible heterojunction perovskite detector is 100-120 μm.

4. The flexible heterojunction perovskite detector according to any one of claims 1 to 3, characterized in that: From the flexible substrate to the three-dimensional perovskite surface, the content of two-dimensional perovskite in the three-dimensional perovskite gradually decreases; from the flexible substrate to the two-dimensional perovskite surface, the content of three-dimensional perovskite in the two-dimensional perovskite gradually decreases.

5. A method for preparing a flexible heterojunction perovskite detector, characterized in that: The following steps are involved: Step 1: Apply a three-dimensional perovskite precursor solution on one side of a flexible substrate, vacuum filter, and then anneal, repeating the application, vacuum filtration, and annealing process until the flexible substrate is saturated with the three-dimensional perovskite solution; the three-dimensional perovskite is CH3NH3PbI3 (MAPbI3); Step 2: Apply a two-dimensional perovskite precursor solution on the other side of the flexible substrate, vacuum filter and anneal, repeat the application, vacuum filtration and annealing process until the other side of the flexible substrate cannot be filled with the two-dimensional perovskite precursor solution, and obtain a filled film; the two-dimensional perovskite is (C6H5CH2CH2NH3)2PbI4 (PEA2PbI4) or C6N2H 16 PbI4[(3-AMP)PbI4]; Step 3, heat-pressing the filling film to obtain a hot-pressed filling film; Step 4: evaporate metal electrodes on both sides of the hot-pressed filling film to obtain a flexible heterojunction perovskite detector.

6. The method for preparing a flexible heterojunction perovskite detector according to claim 5, characterized in that: In step 1, the concentration of the three-dimensional perovskite solution is 1.8-2.2 M, the solute is PbI2, CH3NH3I (MAI) and CH3NH3Cl (MACl) in a molar ratio of 1:0.90:0.22, and the solvent is ethylene glycol methyl ether (2Me).

7. The method for preparing a flexible heterojunction perovskite detector according to claim 6, characterized in that: In step 2, the concentration of the two-dimensional perovskite solution is 1.2 M, the solutes are PEA2PbI4 and (3-AMP)PbI4, and the solvents are a mixed solution of DMF and DMSO.

8. The method for preparing a flexible heterojunction perovskite detector according to any one of claims 5 to 7, characterized in that: In step 3, the hot pressing process is divided into two stages: in the first stage, the heating rate is 1~2°C / min, the hot pressing pressure is 4~6 MPa, the hot pressing time is 10~30 min, and the hot pressing temperature is 40~70°C; in the second stage, the heating rate is 1~2°C / min, the hot pressing pressure is 10~12 MPa, the hot pressing time is 30~50 min, and the hot pressing temperature is 110~150°C.

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