A flexible metal-free perovskite X-ray detector and a preparation method thereof

Abstract

The application discloses a flexible metal-free perovskite X-ray detector and a preparation method thereof. A metal-free perovskite precursor solution is filled into a flexible high polymer porous polymer nylon thick film through vacuum filtration. During a heating and annealing process, the perovskite filled in the flexible high polymer nylon film is uniformly heated, slowly crystallizes in the skeleton of the flexible high polymer nylon film with the volatilization of the solvent, and the proportion of the perovskite is improved through secondary filling and secondary annealing. The peeling and separation of the perovskite from the flexible substrate during the bending process of the flexible metal-free perovskite thick film are prevented through a hot-pressing process. The method prepares an X-ray detector based on the flexible metal-free perovskite filling thick film, obtains the flexible metal-free perovskite X-ray detector, provides a new idea for the application of the next generation of wearable electronic products, and promotes the development of large-area, flexible and metal-free perovskite X-ray detector devices.

Description

Technical Field

[0001] This invention belongs to the field of X-ray detection technology and relates to a flexible metal-free perovskite X-ray detector and its preparation method. Background Technology

[0002] X-ray detection technology is widely used in medical diagnosis, security inspection, non-destructive testing, and quality inspection. Metal halide perovskites possess advantages such as strong X-ray attenuation, fast optical response, tunable bandgap, and low-temperature manufacturing processes, making them suitable next-generation semiconductor materials for X-ray detectors. High-sensitivity and low-detection-limit X-ray detectors are beneficial for medical imaging applications.

[0003] To date, high-quality metal-based perovskite single crystals with a diameter of 5.2 × 10⁻⁶ have been achieved. 6 μC Gyair –1 cm –2 Its ultra-high sensitivity and 0.1 nGy air s –1 The low detection limit of perovskite far exceeds that of commercially available X-ray detectors based on amorphous selenium, crystalline silicon, and germanium. This demonstrates that perovskite is a promising candidate material for high-performance and low-cost X-ray detectors. However, growing single crystals large enough for device integration is very time-consuming, and the brittleness of single crystals makes device integration and fabrication difficult. These drawbacks hinder the commercial application of perovskite as an X-ray detector. The emergence of flexible perovskite X-ray detectors overcomes these drawbacks. For example, flexible X-ray detectors with metal-based perovskite-filled polymer films have been reported to achieve sensitivities up to nearly 10,000 μC. -1 cm -2 Excellent curved surface X-ray imaging has been achieved. However, the lack of biocompatibility, environmental friendliness, and portability of metal-based perovskites limits their potential as wearable electronic devices. Furthermore, flexible metal-free perovskite X-ray detectors have been developed. However, traditional flexible metal-free perovskites often suffer from delamination and detachment from the flexible substrate during bending, which significantly affects both device performance and stability. This limits the commercial application of flexible metal-free perovskites as flexible wearable X-ray detectors. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a flexible metal-free perovskite X-ray detector and its preparation method to solve the problems of heavy metal content, non-biological environmental friendliness, low performance and unstable device performance of existing flexible perovskite X-ray detectors, which make it difficult to prepare large-area flexible metal-free perovskite X-ray detectors with high sensitivity and low detection limit.

[0005] To achieve the above objectives, the present invention employs the following technical solution:

[0006] A method for fabricating a flexible metal-free perovskite X-ray detector includes the following steps:

[0007] Step 1: Prepare a metal-free perovskite precursor solution, wherein the solute in the metal-free perovskite precursor solution is MDABCO-NH4X3, the solvent is water, and X is a halogen.

[0008] Step 2: Place the flexible polymer nylon membrane in a sand core funnel, and filter the sand core funnel by vacuum pumping. Add the metal-free perovskite precursor solution dropwise into the sand core funnel. During vacuum filtration, the metal-free perovskite precursor solution permeates into the flexible polymer nylon membrane, thus obtaining a flexible polymer nylon membrane filled with the metal-free perovskite precursor solution.

[0009] Step 3: Heat the flexible polymer nylon membrane filled with a metal-free perovskite precursor solution using a hot stage.

[0010] Step 4: Repeat steps 2 and 3 to obtain a flexible metal-free perovskite-filled thick film.

[0011] Step 5: Press the flexible metal-free perovskite-filled thick film obtained in Step 4 through a hot press to obtain a pressurized flexible metal-free perovskite-filled thick film with a thickness of 10 μm to 120 μm.

[0012] Step 6: Deposit interdigitated electrodes on the flexible metal-free perovskite-filled thick film obtained in step 5 to obtain a flexible metal-free perovskite thick film X-ray detector.

[0013] A further improvement of the present invention is that:

[0014] Preferably, in step 1, the concentration of the metal-free perovskite precursor solution is 0.1 mmol / L to 5 mol / L.

[0015] Preferably, in step 1, the preparation method of the metal-free perovskite precursor solution is to dissolve [MDABCO]X, NH4X and HX together in deionized water at a molar ratio of 1:1:1, and then stir to obtain the metal-free perovskite precursor solution, wherein X is Cl, Br or I.

[0016] Preferably, in step 2, the area of ​​the flexible polymer nylon film is 0.1 cm². 2 ~30cm 2 The skeleton diameter is 1μm to 10μm, and the pore size is 1μm to 10μm.

[0017] Preferably, in step 2, the filtration pressure is 0.1 Pa to 10 Pa, and the filtration time is 10 s to 60 s.

[0018] Preferably, in step 3, the heating temperature is 30℃~150℃ and the heating time is 2h~4h.

[0019] Preferably, in step 5, the pressure during the pressurization process is 8MPa to 12MPa, and the pressurization time is 2h to 4h.

[0020] Preferably, in step 5, the temperature during the pressurization process is 60℃~180℃.

[0021] Preferably, in step 5, the thickness of the interdigitated electrodes is 30nm–150nm, the finger width is 10nm–1mm, the spacing is 10nm–1mm, the finger length is 10nm–10mm, and the photosensitive area is 200nm. 2 ~40mm 2 .

[0022] A flexible metal-free perovskite X-ray detector prepared by any one of the above methods, wherein the detector is a flexible polymer nylon membrane filled with the metal-free perovskite, wherein the metal-free perovskite is MDABCO-NH4X3, wherein X is Cl, Br or I.

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

[0024] This invention discloses a method for fabricating a flexible metal-free perovskite X-ray detector. The method involves filling a metal-free perovskite precursor solution into a flexible porous polymer nylon thick film via vacuum filtration. During heating and annealing, the perovskite within the flexible polymer nylon film is heated uniformly. As the solvent evaporates, the perovskite slowly crystallizes within the flexible polymer nylon film framework. Secondary filling and annealing are used to increase the specific gravity of the perovskite. Hot pressing is employed to prevent the perovskite from peeling off from the flexible substrate during bending. The entire process is simple and feasible, and the fabrication process is straightforward, clean, and pollution-free. This method, based on a flexible metal-free perovskite-filled thick film, fabricates an X-ray detector, providing a new approach for next-generation wearable electronics and advancing the development of large-area, flexible, metal-free perovskite X-ray detection devices.

[0025] This invention also discloses a flexible metal-free perovskite X-ray detector. The flexible metal-free perovskite thick film is a composite film of metal-free perovskite and a flexible polymer substrate nylon film. The prepared flexible film has a tight bond between the perovskite and the nylon film, good flexibility, and overcomes the disadvantage of the metal-free perovskite peeling off from the flexible substrate due to bending during actual use. It has good crystallinity, smooth surface, high quality, good stability, and the size can be adjusted according to the size of the substrate. It is easy to deposit electrodes on its surface to prepare a high-sensitivity flexible X-ray detector. Attached Figure Description

[0026] Figure 1 This is a flowchart illustrating the preparation process of a flexible, metal-free perovskite-filled thick film as described in an example of the present invention.

[0027] Figure 2 This is a biocompatible, flexible, metal-free perovskite-filled thick-film X-ray detector obtained by the preparation method described in Example 1 of this invention.

[0028] Figure 3 The image shows the current-time curves of the flexible metal-free perovskite-filled thick-film X-ray detector obtained by the preparation method described in Example 1 of this invention under different X-ray doses.

[0029] Figure 4 The performance diagram shows the flexible metal-free perovskite-filled thick-film X-ray detector obtained by the preparation method described in Example 1 of this invention. Detailed Implementation

[0030] The present invention will now be described in further detail with reference to the accompanying drawings:

[0031] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. The terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Furthermore, unless otherwise explicitly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection or a detachable connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two elements. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0032] An embodiment of the present invention is a method for preparing a flexible metal-free perovskite-filled thick film for an X-ray detector, comprising the following steps: solution preparation, filtration, annealing, secondary filtration, secondary annealing, heating and pressurization (a detailed preparation flowchart is attached). Figure 1 As shown):

[0033] Step 1: Preparation of metal-free perovskite precursor solution

[0034] A metal-free perovskite precursor solution A was prepared by dissolving [MDABCO]X, NH4X, and HX in deionized water at a molar ratio of 1:1:1 and stirring. MDABCO was methyltriethylenediamine, and the solution concentration was 0.1 mmol / L to 5 mol / L. After stirring for 24 h, the solution was filtered through a 0.45 μm filter to obtain a clear metal-free perovskite precursor solution A: MDABCO-NH4X3, where X was Cl, Br, or I. The filtered metal-free perovskite precursor had low impurity content and high purity, preparing it for the following vacuum filtration process. The solvent in this process is an aqueous solution, which facilitates aspiration during vacuum filtration.

[0035] Step 2: Fill a cavity with the metal-free perovskite precursor solution A using a vacuum filtration device to a volume of approximately 0.1 cm². 2 ~30cm 2 A flexible, porous organic polymer nylon membrane with a framework diameter of 1μm to 10μm, a pore size of 1μm to 10μm, and a thickness of 10μm to 120μm is used. The pressure during vacuum filtration is 0.1Pa to 10Pa, and the filtration time is 10s to 60s. The vacuum filtration process prevents the metal-free perovskite precursor solution from being easily oxidized.

[0036] Step 3: Place the flexible porous organic polymer substrate nylon membrane filled with metal-free perovskite precursor solution A onto a hot plate to complete the annealing process. The annealing temperature is 30℃~150℃, and the annealing time is 2h~4h.

[0037] Step 4, Secondary Filling. The flexible metal-free perovskite-filled thick film after heating, annealing, and crystallization is filled again with the same metal-free perovskite precursor solution A through vacuum filtration. The filtration pressure during the secondary filling is 0.1 Pa to 10 Pa, and the filtration time is 10 s to 60 s.

[0038] Step 5, Secondary Annealing. The flexible, metal-free perovskite-filled thick film after secondary filling as described in Step 4 is transferred to a hot plate for secondary annealing. The temperature of the hot plate is set to 30℃~150℃, and the annealing time is 2h~4h.

[0039] Step 6: Hot-press the annealed flexible metal-free perovskite-filled thick film. The annealed flexible metal-free perovskite-filled thick film is heated and pressurized at 60℃~180℃ and 8MPa~12MPa for 2h~4h to obtain the hot-pressed flexible metal-free perovskite-filled thick film. The hot-pressed flexible metal-free perovskite-filled thick film has good crystallinity. The hot-pressing process ensures a tighter and stronger bond between the metal-free perovskite and the flexible substrate, preventing peeling or detachment of the perovskite from the flexible substrate during bending, thus avoiding affecting the performance and stability of the flexible metal-free perovskite X-ray detector device.

[0040] Step 7: Planar interdigitated electrodes are deposited onto the flexible metal-free perovskite-filled thick film to obtain a flexible metal-free perovskite X-ray detector. The interdigitated electrode thickness is 30 nm–150 nm, the finger width is 10 nm–1 mm, the spacing is 10 nm–1 mm, the finger length is 10 nm–10 mm, and the photosensitive area is 200 nm. 2 ~40mm 2 The interdigitated electrodes are made of at least one of gold, silver, and graphene.

[0041] Step 8, Photoelectric Conversion Signal Testing of the Flexible Metal-Free Perovskite X-ray Detector: At room temperature, using a Keysight 2450 ammeter, current-time tests were performed under X-ray dose rate ranges of 0.1 μGy to 100 mGy, with an applied voltage of 2V to 200V and a delay time of 5 to 500 ms. The fabricated detector is flexible and portable, with a thickness of approximately 100 micrometers, resulting in better X-ray absorption and attenuation, and facilitating X-ray conversion.

[0042] This invention employs a method of vacuum filtration-filling-heat crystallization-hot pressing recrystallization to prepare flexible metal-free perovskite thick films. Secondary filling and secondary annealing increase the specific gravity of the perovskite, and the hot pressing process prevents the perovskite from peeling off or detaching from the flexible substrate during bending, thereby improving the device performance and stability of the flexible metal-free perovskite X-ray detector.

[0043] This invention also discloses a flexible metal-free perovskite X-ray detector and its fabrication method. The flexible X-ray detector uses two materials: firstly, a bio-environmentally friendly metal-free perovskite with a high atomic number ensuring its X-ray absorption capacity; secondly, the three-dimensional crystal structure of the perovskite provides good electron transport capabilities, making it a good choice for obtaining bio-environmentally friendly, high-performance, and stable devices. The second material is a flexible substrate polymer nylon film. The nylon film is a flexible polymer film with a porous structure suitable for supporting the metal-free perovskite, and the large-scale nylon fibers with a diameter of 10 μm provide good mechanical flexibility. This polymer also exhibits high temperature resistance, high pressure resistance, and radiation resistance. This flexible metal-free perovskite thick film provides excellent conditions for fabricating flexible X-ray detector devices. The fabricated detector device has a simple structure; a high-performance flexible metal-free X-ray detector can be fabricated by depositing a planar interdigitated gold electrode on the smooth composite film surface. This flexible metal-free X-ray detector exhibits good photoelectric performance and stability. These findings open up tremendous new possibilities for high-performance radiation detection using bio-friendly flexible perovskite materials.

[0044] Example 1

[0045] 1. Preparation of metal-free perovskite precursor solution: Weigh 1.016 g MDABCO-I, 0.58 g NH4I, and 2 mL HI and dissolve them in 2 mL deionized water. Stir on a magnetic stirrer for 24 h to ensure complete reaction. After filtration through a 0.45 μm filter, a clear metal-free perovskite precursor solution with a concentration of 4 mmol / L, MDABCO-NH4I3, is obtained.

[0046] 2. Place a flexible polymer nylon membrane in a sand core funnel. Filter the mixture through a vacuum pump. Use a pipette to take 2 mL of clear, metal-free perovskite precursor solution and drop it into the sand core funnel. Turn on the vacuum filtration device. The pressure during filtration and filling is 1 Pa, and the filling time is 10 s. Under suction, fill the porous nylon membrane with the metal-free perovskite precursor solution. The filling area is 20 cm². 2 The skeleton diameter is 10 μm and the film thickness is approximately 100 μm.

[0047] 3. Turn on the hot plate, set the temperature to 80℃, preheat for 10 minutes, transfer the nylon film containing the metal-free perovskite precursor solution to the hot plate, and perform heating annealing for 3 hours.

[0048] 4. Secondary filling. The flexible metal-free perovskite-filled thick film after heating, annealing, and crystallization was filled again with 2 mL of metal-free perovskite precursor solution A through vacuum filtration. The pressure of vacuum filtration during the secondary filling was 2 Pa, and the filtration time was 60 s.

[0049] 5. Secondary annealing. The temperature for secondary annealing is 80℃, and the annealing time is 3 hours.

[0050] 6. The flexible metal-free perovskite-filled thick film after secondary annealing is heated and pressurized by a hot press. The temperature is set at 120℃, the pressure is 10MPa, and the hot pressing time is 3h to obtain the hot-pressed flexible metal-free perovskite-filled thick film.

[0051] 7. Deposit interdigitated gold electrodes with a thickness of 60 nm, a finger width of 50 μm, a finger spacing of 50 μm, and a finger length of 1 mm on the surface of a flexible metal-free perovskite thick film. A flexible metal-free perovskite thick film X-ray detector is obtained. The obtained metal-free perovskite MDABCO-NH4I3 thick film X-ray detector exhibits excellent biocompatibility and flexibility, as shown in the attached figure. Figure 2 As shown, the metal-free perovskite MDABCO-NH4I3 thick-film X-ray detector can achieve good flexibility and bendability as the finger is bent. During the bending process, the perovskite is tightly bonded to the flexible substrate without any detachment or peeling, which is due to the heating and pressurization process.

[0052] At room temperature, a Keysight 2450 ammeter was used to record the response current of the flexible metal-free perovskite thick-film X-ray detector under X-rays to realize the application of flexible metal-free perovskite thick films. The power supply voltage of the ammeter was set to a fixed 5V. The obtained current-time response graph is shown in the attached figure. Figure 3 As shown in the attached document Figure 3 As shown, the device generates a significant response current under X-ray irradiation, demonstrating the feasibility of a flexible metal-free perovskite X-ray detector. By calculating the current density and fitting the current density-dose rate, the device's performance sensitivity was obtained as: 4007.06 μC Gy. air -1 cm -2 As attached Figure 4 As shown.

[0053] Example 2

[0054] 1. Preparation of metal-free perovskite precursor solution: Weigh 1.250g MDABCO-Br2, 0.426g NH4Br, and 2mL HBr and dissolve them in 2mL deionized water. Stir on a magnetic stirrer for 24h to ensure complete reaction. After filtration through a 0.45μm filter, a metal-free perovskite precursor solution MDABCO-NH4Br3 with a concentration of 4.3mmol / L is obtained.

[0055] 2. Place a flexible polymer nylon membrane in a sand core funnel. Filter the sand core funnel containing the flexible polymer nylon membrane using a vacuum filtration pump. Use a pipette to take 2 mL of the metal-free perovskite precursor solution and drop it into the sand core funnel. Turn on the vacuum filtration device. The pressure during filtration filling is 1 Pa, and the filling time is 10 s. Under suction, fill the porous nylon membrane with the metal-free perovskite precursor solution. The filling area is 20 cm². 2 The skeleton diameter is 10 μm and the film thickness is approximately 100 μm.

[0056] 3. Turn on the hot plate, set the temperature to 80℃, preheat for 10 minutes, transfer the nylon film containing the metal-free perovskite precursor solution to the hot plate, and perform heating annealing for 3 hours.

[0057] 4. Secondary filling. The flexible metal-free perovskite-filled thick film after heating, annealing, and crystallization was filled again with the same metal-free perovskite precursor solution A through vacuum filtration. The filtration pressure during the secondary filling was 2 Pa, and the filtration time was 60 s.

[0058] 5. Secondary annealing. The temperature for secondary annealing is 80℃, and the annealing time is 3 hours.

[0059] 6. The flexible metal-free perovskite-filled thick film after secondary annealing is heated and pressurized by a hot press. The temperature is set at 100℃, the pressure is 10MPa, and the hot pressing time is 3h to obtain the hot-pressed flexible metal-free perovskite-filled thick film.

[0060] 7. Deposit interdigitated gold electrodes with a thickness of 60 nm, a finger width of 50 μm, a finger spacing of 50 μm, and a finger length of 1 mm on the surface of a flexible metal-free perovskite thick film. Obtain a flexible metal-free perovskite thick film X-ray detector.

[0061] Example 3

[0062] 1. Preparation of metal-free perovskite precursor solution: Weigh 1.000g MDABCO-Cl2, 0.268g NH4Cl, and 2mL HCl, dissolve them in 2mL deionized water, stir on a magnetic stirrer for 24h to ensure complete reaction, and filter through a 0.45μm filter to obtain a metal-free perovskite precursor solution MDABCO-NH4Cl3 with a concentration of 5mmol / L.

[0063] 2. Place a flexible polymer nylon membrane in a sand core funnel. Filter the sand core funnel containing the flexible polymer nylon membrane using a vacuum filtration pump. Use a pipette to take 2 mL of the metal-free perovskite precursor solution and drop it into the sand core funnel. Turn on the vacuum filtration device. The pressure during filtration filling is 1 Pa, and the filling time is 10 s. Under suction, fill the porous nylon membrane with the metal-free perovskite precursor solution. The filling area is 20 cm². 2 The skeleton diameter is 10 μm and the film thickness is approximately 100 μm.

[0064] 3. Turn on the hot plate, set the temperature to 40℃, preheat for 10 minutes, transfer the nylon membrane containing the metal-free perovskite precursor solution to the hot plate, and perform heating annealing for 3 hours.

[0065] 4. Secondary filling. The flexible metal-free perovskite-filled thick film after heating, annealing, and crystallization was filled again with the same metal-free perovskite precursor solution A through vacuum filtration. The filtration pressure during the secondary filling was 2 Pa, and the filtration time was 60 s.

[0066] 5. Secondary annealing. The temperature for secondary annealing is 40℃, and the annealing time is 3 hours.

[0067] 6. The flexible metal-free perovskite-filled thick film after secondary annealing is heated and pressurized by a hot press. The temperature is set at 80℃, the pressure is 10MPa, and the hot pressing time is 3h to obtain the hot-pressed flexible metal-free perovskite-filled thick film.

[0068] 7. Deposit interdigitated gold electrodes with a thickness of 60 nm, a finger width of 50 μm, a finger spacing of 50 μm, and a finger length of 1 mm on the surface of a flexible metal-free perovskite thick film. Obtain a flexible metal-free perovskite thick film X-ray detector.

[0069] Example 4

[0070] 1. Preparation of metal-free perovskite precursor solution: MDABCO-I, NH4I and HI were weighed in a molar ratio of 1:1:1 and dissolved in deionized water. The mixture was stirred on a magnetic stirrer for 24 h to ensure complete reaction. After filtration through a 0.45 μm filter, a clear metal-free perovskite precursor solution MDABCO-NH4I3 was obtained, yielding a precursor solution with a concentration of 0.1 mmol / L.

[0071] 2. Place a flexible polymer nylon membrane in a sand core funnel. Filter the mixture through a vacuum pump. Use a pipette to take 2 mL of clear, metal-free perovskite precursor solution and drop it into the sand core funnel. Turn on the vacuum filtration device. The pressure during filtration and filling is 2 Pa, and the filling time is 40 s. Under suction, fill the porous nylon membrane with the metal-free perovskite precursor solution. The filling area is 30 cm². 2 The skeleton diameter is 10 μm and the film thickness is approximately 120 μm.

[0072] 3. Turn on the hot plate, set the temperature to 30℃, preheat for 10 minutes, transfer the nylon membrane containing the metal-free perovskite precursor solution to the hot plate, and perform heating annealing for 4 hours.

[0073] 4. Secondary filling. The flexible metal-free perovskite-filled thick film after heating, annealing, and crystallization was filled again with 2 mL of metal-free perovskite precursor solution A through vacuum filtration. The pressure of vacuum filtration during the secondary filling was 2 Pa, and the filtration time was 40 s.

[0074] 5. Secondary annealing. The temperature for secondary annealing is 30℃, and the annealing time is 4 hours.

[0075] 6. The flexible metal-free perovskite-filled thick film after secondary annealing is heated and pressurized by a hot press. The temperature is set at 60℃, the pressure is 8MPa, and the hot pressing time is 4h to obtain the hot-pressed flexible metal-free perovskite-filled thick film.

[0076] 7. Deposit interdigitated gold and silver electrodes with a thickness of 100 nm, a finger width of 10 nm, a spacing of 10 nm, and a finger length of 10 nm on the surface of a flexible metal-free perovskite thick film. Obtain a flexible metal-free perovskite thick film X-ray detector.

[0077] Example 5

[0078] 1. Preparation of metal-free perovskite precursor solution: MDABCO-Br2, NH4Br and HBr were weighed in a molar ratio of 1:1:1 and dissolved in deionized water. The mixture was stirred on a magnetic stirrer for 24 h to ensure complete reaction. After filtration through a 0.45 μm filter, a metal-free perovskite precursor solution MDABCO-NH4Br3 with a concentration of 1 mmol / L was obtained.

[0079] 2. Place a flexible polymer nylon membrane in a sand core funnel. Filter the sand core funnel containing the flexible polymer nylon membrane using a vacuum filtration pump. Use a pipette to take 2 mL of the metal-free perovskite precursor solution and drop it into the sand core funnel. Turn on the vacuum filtration device. The pressure during filtration and filling is 5 Pa, and the filtration and filling time is 30 s. Under suction, the metal-free perovskite precursor solution fills the porous nylon membrane. The filling area is 0.1 cm². 2 The skeleton diameter is 1 μm and the film thickness is approximately 10 μm.

[0080] 3. Turn on the hot plate, set the temperature to 150℃, preheat for 10 minutes, transfer the nylon film containing the metal-free perovskite precursor solution to the hot plate, and perform heating annealing for 2 hours.

[0081] 4. Secondary filling. The flexible metal-free perovskite-filled thick film after heating, annealing, and crystallization was filled again with the same metal-free perovskite precursor solution A through vacuum filtration. The filtration pressure during the secondary filling was 5 Pa, and the filtration time was 30 s.

[0082] 5. Secondary annealing. The temperature for secondary annealing is 150℃, and the annealing time is 2 hours.

[0083] 6. The flexible metal-free perovskite-filled thick film after secondary annealing is heated and pressurized by a hot press. The temperature is set at 180℃, the pressure is 9MPa, and the hot pressing time is 3h to obtain the hot-pressed flexible metal-free perovskite-filled thick film.

[0084] 7. A flexible metal-free perovskite thick film X-ray detector was obtained by depositing interdigitated silver electrodes with a thickness of 150 nm, a finger width of 10 μm, a spacing of 10 μm, and a finger length of 1 μm on the surface of the film.

[0085] Example 6

[0086] 1. Preparation of metal-free perovskite precursor solution: MDABCO-Cl2, NH4Cl, and HCl were weighed in a molar ratio of 1:1:1 and dissolved in deionized water. The mixture was stirred on a magnetic stirrer for 24 hours to ensure complete reaction. After filtration through a 0.45 μm filter, a metal-free perovskite precursor solution MDABCO-NH4Cl3 with a concentration of 2 mmol / L was obtained.

[0087] 2. Place a flexible polymer nylon membrane in a sand core funnel. Filter the sand core funnel containing the flexible polymer nylon membrane using a vacuum filtration pump. Use a pipette to take 2 mL of the metal-free perovskite precursor solution and drop it into the sand core funnel. Turn on the vacuum filtration device. The pressure during filtration filling is 0.1 Pa, and the filling time is 60 s. Under suction, fill the porous nylon membrane with the metal-free perovskite precursor solution. The filling area is 10 cm². 2 The skeleton diameter is 5 μm and the film thickness is approximately 60 μm.

[0088] 3. Turn on the hot plate, set the temperature to 45℃, preheat for 10 minutes, transfer the nylon film containing the metal-free perovskite precursor solution to the hot plate, and perform heating annealing for 3 hours.

[0089] 4. Secondary filling. The flexible metal-free perovskite-filled thick film after heating, annealing, and crystallization was filled again with the same metal-free perovskite precursor solution A through vacuum filtration. The filtration pressure during the secondary filling was 0.1 Pa, and the filtration time was 60 s.

[0090] 5. Secondary annealing. The temperature for secondary annealing is 45℃, and the annealing time is 3 hours.

[0091] 6. The flexible metal-free perovskite-filled thick film after secondary annealing is heated and pressurized by a hot press. The temperature is set at 90℃, the pressure is 12MPa, and the hot pressing time is 2h to obtain the hot-pressed flexible metal-free perovskite-filled thick film.

[0092] 7. Deposit interdigitated gold electrodes with a thickness of 30 nm, a finger width of 1 mm, a finger spacing of 1 mm, and a finger length of 100 μm on the surface of a flexible metal-free perovskite thick film. Obtain a flexible metal-free perovskite thick film X-ray detector.

[0093] Example 7

[0094] 1. Preparation of metal-free perovskite precursor solution: MDABCO-I, NH4I, and HI were weighed according to a molar ratio of 1:1:1 and dissolved in deionized water. The mixture was stirred on a magnetic stirrer for 24 hours to ensure complete reaction. After filtration through a 0.45 μm filter, a clear metal-free perovskite precursor solution with a concentration of 3 mmol / L, MDABCO-NH4I3, was obtained.

[0095] 2. Place a flexible polymer nylon membrane in a sand core funnel. Filter the mixture through a vacuum pump. Use a pipette to take 2 mL of clear, metal-free perovskite precursor solution and drop it into the sand core funnel. Turn on the vacuum filtration device. The pressure during filtration and filling is 10 Pa, and the filling time is 10 s. Under suction, fill the porous nylon membrane with the metal-free perovskite precursor solution. The filling area is 20 cm². 2 The skeleton diameter is 8 μm and the film thickness is approximately 120 μm.

[0096] 3. Turn on the hot plate, set the temperature to 100℃, preheat for 10 minutes, transfer the nylon film containing the metal-free perovskite precursor solution to the hot plate, and perform heating annealing for 2 hours.

[0097] 4. Secondary filling. The flexible metal-free perovskite-filled thick film after heating, annealing, and crystallization was filled again with 2 mL of metal-free perovskite precursor solution A through vacuum filtration. The pressure of vacuum filtration during the secondary filling was 10 Pa, and the filtration time was 10 s.

[0098] 5. Secondary annealing. The temperature for secondary annealing is 100℃, and the annealing time is 2 hours.

[0099] 6. The flexible metal-free perovskite-filled thick film after secondary annealing is heated and pressurized by a hot press. The temperature is set at 150℃, the pressure is 10MPa, and the hot pressing time is 3h to obtain the hot-pressed flexible metal-free perovskite-filled thick film.

[0100] 7. A flexible metal-free perovskite thick film X-ray detector is obtained by depositing interdigitated graphene electrodes with a thickness of 40 nm, a finger width of 50 nm, a spacing of 50 nm, and a finger length of 500 nm on the surface of the film.

[0101] Example 8

[0102] 1. Preparation of metal-free perovskite precursor solution: MDABCO-Br2, NH4Br and HBr were weighed in a molar ratio of 1:1:1 and dissolved in 2 mL of deionized water. The mixture was stirred on a magnetic stirrer for 24 h to ensure complete reaction. After filtration through a 0.45 μm filter, a metal-free perovskite precursor solution MDABCO-NH4Br3 with a concentration of 3 mmol / L was obtained.

[0103] 2. Place a flexible polymer nylon membrane in a sand core funnel. Filter the membrane using a vacuum pump. Add 2 mL of the metal-free perovskite precursor solution dropwise into the funnel. Turn on the vacuum filtration device. The filling pressure is 0.5 Pa, and the filling time is 50 s. Under suction, fill the porous nylon membrane with the metal-free perovskite precursor solution. The filling area is 5 cm². 2 The skeleton diameter is 5μm and the film thickness is approximately 50μm.

[0104] 3. Turn on the hot plate, set the temperature to 60℃, preheat for 10 minutes, transfer the nylon membrane containing the metal-free perovskite precursor solution to the hot plate, and perform heating annealing for 4 hours.

[0105] 4. Secondary filling. The flexible metal-free perovskite-filled thick film after heating, annealing, and crystallization was filled again with the same metal-free perovskite precursor solution A through vacuum filtration. The filtration pressure during the secondary filling was 0.5 Pa, and the filtration time was 50 s.

[0106] 5. Secondary annealing. The temperature for secondary annealing is 60℃, and the annealing time is 4 hours.

[0107] 6. The flexible metal-free perovskite-filled thick film after secondary annealing is heated and pressurized by a hot press. The temperature is set at 160℃, the pressure is 10MPa, and the hot pressing time is 2h to obtain the hot-pressed flexible metal-free perovskite-filled thick film.

[0108] 7. A flexible metal-free perovskite thick film X-ray detector was obtained by depositing interdigitated gold electrodes with a thickness of 120 nm, a finger width of 50 μm, a spacing of 50 μm, and a finger length of 5 mm on the surface of the film.

[0109] Example 9

[0110] 1. Preparation of metal-free perovskite precursor solution: MDABCO-Cl2, NH4Cl and HCl were weighed in a molar ratio of 1:1:1 and dissolved in deionized water. The mixture was stirred on a magnetic stirrer for 24 h to ensure complete reaction. After filtration through a 0.45 μm filter, a metal-free perovskite precursor solution MDABCO-NH4Cl3 with a concentration of 8 mmol / L was obtained.

[0111] 2. Place a flexible polymer nylon membrane in a sand core funnel. Filter the sand core funnel containing the flexible polymer nylon membrane using a vacuum filtration pump. Use a pipette to take 2 mL of the metal-free perovskite precursor solution and drop it into the sand core funnel. Turn on the vacuum filtration device. The pressure during filtration filling is 8 Pa, and the filling time is 20 s. Under suction, the metal-free perovskite precursor solution fills the porous nylon membrane. The filling area is 1 cm². 2 The skeleton diameter is 10 μm and the film thickness is approximately 100 μm.

[0112] 3. Turn on the hot plate, set the temperature to 40℃, preheat for 10 minutes, transfer the nylon membrane containing the metal-free perovskite precursor solution to the hot plate, and perform heating annealing for 3 hours.

[0113] 4. Secondary filling. The flexible metal-free perovskite-filled thick film after heating, annealing, and crystallization was filled again with the same metal-free perovskite precursor solution A through vacuum filtration. The filtration pressure during the secondary filling was 8 Pa, and the filtration time was 20 s.

[0114] 5. Secondary annealing. The temperature for secondary annealing is 40℃, and the annealing time is 3 hours.

[0115] 6. The flexible metal-free perovskite-filled thick film after secondary annealing is heated and pressurized by a hot press. The temperature is set at 180℃, the pressure is 12MPa, and the hot pressing time is 4h to obtain the hot-pressed flexible metal-free perovskite-filled thick film.

[0116] 7. A flexible metal-free perovskite thick film X-ray detector was obtained by depositing interdigitated graphene electrodes with a thickness of 80 nm, a finger width of 500 μm, a spacing of 500 μm, and a finger length of 10 mm on the surface of the film.

[0117] 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 within the protection scope of the present invention.

Claims

1. A method for fabricating a flexible metal-free perovskite X-ray detector, characterized in that, Includes the following steps: Step 1: Prepare a metal-free perovskite precursor solution. The solute in the metal-free perovskite precursor solution is MDABCO-NH4X3, the solvent is water, and X is a halogen. The preparation method of the metal-free perovskite precursor solution is to dissolve [MDABCO]X, NH4X and HX together in deionized water at a molar ratio of 1:1:1, and stir to obtain a metal-free perovskite precursor solution, wherein X is Cl, Br or I. Step 2: Place the flexible polymer nylon membrane in a sand core funnel. Use a vacuum pump to filter the sand core funnel while adding a metal-free perovskite precursor solution dropwise. During vacuum filtration, the metal-free perovskite precursor solution permeates into the flexible polymer nylon membrane, thus obtaining a flexible polymer nylon membrane filled with the metal-free perovskite precursor solution; the area of ​​the flexible polymer nylon membrane is 0.1 cm². 2 ~30 cm 2 The skeleton diameter is 1 µm ~ 10 µm, and the pore size is 1 µm ~ 10 µm; Step 3: Heat the flexible polymer nylon membrane filled with a metal-free perovskite precursor solution using a hot stage. Step 4: Repeat steps 2 and 3 to obtain a flexible metal-free perovskite-filled thick film. Step 5: Press the flexible metal-free perovskite-filled thick film obtained in Step 4 using a hot press to obtain a pressurized flexible metal-free perovskite-filled thick film with a thickness of 10 μm to 120 μm; the temperature during the pressurization process is 60℃ to 180℃. Step 6: Deposit interdigitated electrodes on the flexible metal-free perovskite-filled thick film obtained in step 5 to obtain a flexible metal-free perovskite thick film X-ray detector.

2. The method for fabricating a flexible metal-free perovskite X-ray detector according to claim 1, characterized in that, In step 1, the concentration of the metal-free perovskite precursor solution is 0.1 mmol / L to 5 mol / L.

3. The method for fabricating a flexible metal-free perovskite X-ray detector according to claim 1, characterized in that, In step 2, the filtration pressure is 0.1 Pa ~ 10 Pa, and the filtration time is 10 s ~ 60 s.

4. The method for fabricating a flexible metal-free perovskite X-ray detector according to claim 1, characterized in that, In step 3, the heating temperature is 30℃~150℃, and the heating time is 2 h~4 h.

5. The method for fabricating a flexible metal-free perovskite X-ray detector according to claim 1, characterized in that, In step 5, the pressure during the pressurization process is 8 MPa ~ 12 MPa, and the pressurization time is 2 h ~ 4 h.

6. The method for fabricating a flexible metal-free perovskite X-ray detector according to claim 1, characterized in that, In step 5, the thickness of the interdigitated electrodes is 30 nm to 150 nm, the finger width is 10 nm to 1 mm, the spacing is 10 nm to 1 mm, the finger length is 10 nm to 10 mm, and the photosensitive area is 200 nm. 2 ~40 mm 2 .

7. A flexible metal-free perovskite X-ray detector prepared by the method according to any one of claims 1-6, characterized in that, The detector is a flexible polymer nylon membrane filled with a metal-free perovskite, wherein the metal-free perovskite is MDABCO-NH4X3, and X is Cl, Br or I.

Images