A lead halide perovskite absorption layer based on a near-space sublimation method, and a preparation method and application thereof

Abstract

This invention discloses a lead halide perovskite absorber layer based on near-space sublimation, its preparation method, and its application. The method includes the following steps: CsBr and PbBr2 powders are ball-milled and mixed, then sintered to obtain precursor powder; the precursor powder is placed in an evaporation zone, and a conductive substrate is placed in a deposition zone, with a distance of 1-10 cm between the evaporation and deposition zones; a buffer layer is deposited at low temperature after vacuuming the chamber; the temperature of the deposition zone is kept constant, and the temperature of the evaporation zone is adjusted to 575-675℃, held at this constant temperature for 5-45 min to obtain the lead halide perovskite absorber layer. This invention employs a near-space sublimation method, utilizing an in-situ optimization strategy for the homologous buffer layer to achieve nucleation and growth on the conductive substrate, avoiding cracking failure during thick film growth. The resulting perovskite thick film exhibits uniform size, good crystallinity, and high stability. When fabricated into an X-ray detector, it can achieve devices with high stability, low detection limit, and high resolution.

Description

Technical Field

[0001] This invention relates to the field of semiconductor materials technology, specifically to a lead halide perovskite absorber layer based on near-space sublimation, its preparation method, and its application. Background Technology

[0002] X-ray imaging technology, as a core technology of modern medical imaging, plays an indispensable role in the diagnosis of major diseases such as cardiovascular diseases and cancer. Currently, the equipment used to detect X-rays is mainly divided into two types: direct detectors and indirect detectors. Direct detectors simplify the light signal conversion steps in indirect detectors and have the advantages of high charge conversion efficiency and high spatial resolution.

[0003] Metal halide perovskite materials possess high density, high atomic number, and excellent carrier transport properties, exhibiting strong X-ray absorption and efficient charge extraction capabilities, meeting the material requirements of direct-type detectors. Compared to organic-inorganic hybrid perovskites, all-inorganic perovskite materials offer higher density and stability, demonstrating great potential for next-generation X-ray imaging applications.

[0004] For perovskite X-ray detectors to be suitable for flat-panel imaging, the absorption layer must be thick enough to absorb X-rays, scalable in size, and fabricated at low temperatures. While single-crystal materials offer excellent sensitivity, their limited scalability hinders large-scale production, making large-area polycrystalline thick films the primary choice for detector absorption layers. Current large-area perovskite thick films are mostly fabricated using solution-based processes such as blade coating, spraying, and screen printing. However, solvent residues from thick film annealing often lead to defects such as pinholes and solvent inclusions, severely impairing device performance.

[0005] CN115000310A discloses a perovskite coating and its preparation method, as well as an X-ray detector. The method involves preparing a precursor sol containing additives, surfactants, organic ligands, a metal halide BXa, and a halide AX. The precursor sol is deposited on a substrate and then annealed to obtain the perovskite coating. The additives contain polar groups and volatilize during annealing. The surfactant promotes the formation of a gel from the precursor. The organic ligands are NH-containing halide salts. The perovskite in the perovskite coating has the structural formula A'2A. n1 B n X 3n+1 This preparation method allows the perovskite coating to maintain high sensitivity while further improving stability, thereby achieving stable X-ray detection.

[0006] CN121442932A discloses a method, system, and medium for fabricating a pixelated perovskite-based array X-ray imaging detector. The method includes: selecting a polyimide film and forming a through-hole array pattern on the polyimide film; performing layered ablation on the polyimide film using a laser drilling process to obtain through-holes; injecting UV-removable adhesive into the through-holes to form a bottom barrier layer, forming sidewall partitions along annular adhesive ridges printed on the inner wall of the through-holes, and depositing an Au electrode layer; removing the UV-removable adhesive using a UV adhesive stripping solution, and growing perovskite crystals in the through-holes using a solution method or solid-state melting method; fabricating a TFT array on the polyimide film, and forming an insulating coating on the bottom of the polyimide film using a vapor deposition or chemical vapor deposition process to obtain the imaging detector; achieving high-precision and high-reliability integration of the polyimide film and the TFT array, improving charge collection efficiency, reducing signal crosstalk, and realizing micron-level pixel size detection.

[0007] In contrast, vapor deposition technology offers precise thickness control, scalability, and a solvent-free environment. However, when faced with absorber layer thickness requirements of hundreds of micrometers, traditional thermal evaporation technology often suffers from low deposition efficiency, while chemical vapor deposition, which enables high-throughput growth, limits the size of the substrate. Summary of the Invention

[0008] To address the limitations in polycrystalline thick film size, slow growth, and insufficient stability of perovskite thick films in the fabrication of perovskite X-ray detectors, this invention provides a method for fabricating an all-inorganic lead halide perovskite X-ray detector. The absorber layer of this detector is grown using a near-space sublimation method, employing an in-situ optimization strategy with a homologous buffer layer to nucleate and grow on a conductive substrate. This avoids cracking failures during thick film growth, resulting in a perovskite thick film with uniform size, good crystallinity, and high stability.

[0009] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A method for preparing a lead halide perovskite absorber layer based on near-space sublimation includes the following steps: Step 1: CsBr and PbBr2 powders are ball-milled and then sintered to obtain precursor powder; Step 2: In the near-space sublimation furnace, the precursor powder is loaded into a quartz boat and placed in the evaporation zone, and the conductive substrate is placed in the deposition zone. The distance between the evaporation zone and the deposition zone is 1-10 cm. After the chamber is evacuated, the temperature of the deposition zone is set to 100-200℃ and the temperature of the evaporation zone is set to 450-550℃. The constant temperature is maintained for 3-15 min. Step 3: Keep the temperature of the deposition zone constant, adjust the temperature of the evaporation zone to 575-675℃, and maintain the constant temperature for 5-45 minutes to obtain the lead halide perovskite absorber layer.

[0010] In perovskite thin film preparation via vapor deposition, the Volmer-Weber growth mode is commonly used due to the low affinity between perovskite and the substrate. When the deposition rate is too high, disordered grain arrangement and stress can induce porosity and delamination at the buried interface. As the film thickness increases, stress caused by the mismatch in thermal expansion coefficients can lead to through-cracks. Furthermore, the random merging of these islands can create defect grain boundaries, becoming non-radiative recombination centers, severely impairing the photoelectric conversion efficiency of the device. Therefore, this invention introduces a homogeneous buffer layer capable of in-situ regulation and employs a two-step deposition strategy that separates the nucleation and growth stages. First, a stable and uniformly distributed seed layer is grown at a low deposition rate, followed by directional grain growth at a high deposition rate, where the deposition rate is controlled by the temperature of the evaporation source. By utilizing the buffer layer for near-space sublimation, this high-rate thin film deposition method improves film quality, resulting in perovskite thin films with controllable thickness, uniform size, good crystallinity, and high stability.

[0011] Preferably, the molar ratio of CsBr to PbBr2 in the precursor powder is 0.9-1.9:1. Preferably, when the molar ratio of CsBr to PbBr2 is 1-1.3:1, the growth rate is faster in the same amount of time; more preferably, the molar ratio of CsBr to PbBr2 is 1.1:1.

[0012] Preferably, in step 2, the chamber is evacuated to below 0.1 Pa. The vacuum level affects the composition of the precursor powder and the molecular path of freedom, causing disordered deposition. Therefore, it is preferable to evacuate the chamber to below 0.1 Pa before proceeding with subsequent operations.

[0013] In this invention, the perovskite layer is prepared by vapor deposition of a precursor powder composed of CsBr and PbBr2. To reduce the compositional differences caused by the different sublimation temperatures of CsBr and PbBr2, the CsBr and PbBr2 are pre-mixed by ball milling. In step 1, the ball milling speed is 300-400 rpm / min, and the mixing time is 10-60 min.

[0014] In step 1, in order to further form a stable Cs-Pb-Br compound from the precursor and improve the uniformity and stability of the thick film, the ball-milled powder is placed in a sealed container under vacuum and sintered at 675-750℃ for 10-20 min.

[0015] Preferably, the temperature of the evaporation zone in step 2 is 480-530℃, and the constant temperature is maintained for 3-15 min. More preferably, the temperature of the evaporation zone in step 2 is 480-500℃; even more preferably, the temperature of the evaporation zone in step 2 is 500℃, and the constant temperature is maintained for 10 min. A more preferred temperature range is the deposition temperature of the buffer layer, which can maintain the buffer layer as a stable CsPbBr3 phase. At a lower deposition rate, this deposition time can form a stable nucleus with medium density and uniform distribution.

[0016] Preferably, in this invention, the thickness of the perovskite layer can be increased by the cyclic deposition method in step 3, resulting in a lead halide perovskite absorption layer with a thickness of 80-200 μm, which can meet the requirements of X-ray detectors for high absorption layer thickness.

[0017] On the other hand, the present invention also provides a lead halide perovskite absorber layer based on near-space sublimation prepared according to the preparation method described above. Furthermore, this invention also provides an all-inorganic lead halide perovskite thick-film X-ray detector, including the lead halide perovskite absorption layer based on the near-space sublimation method. In this invention, stable precursor CsPbBr3 powder is formed through ball milling and pre-sintering, and the perovskite layer is prepared on a conductive substrate using the near-space sublimation method. A homologous buffer layer with in-situ conditioning function is used to reduce buried interface defects, improve crystal quality, and thus reduce cracking and peeling problems commonly encountered in thick-film fabrication. By optimizing key factors such as the ratio, substrate and evaporation source temperature, and transport layer, this absorption layer is fabricated into an X-ray detector, achieving a device with high stability, low detection limit, and high resolution.

[0018] The X-ray detector includes a conductive substrate, a perovskite absorption layer, a hole transport layer, an electron transport layer, and a top electrode; The conductive substrate includes one of silicon wafer, ITO glass, FTO glass, and TFT; the perovskite absorber layer is the lead halide perovskite absorber layer based on near-space sublimation as described in claim 7; the hole transport layer includes PEDOT:PSS and NiO. x One or more of the following; the electron transport layer includes BCP, C 60 The material is one or more of SnO2 and PCBM; the top electrode is one or more of gold, copper, silver, chromium and aluminum.

[0019] This invention also provides the application of the aforementioned all-inorganic lead halide perovskite thick-film X-ray detector in radiation detection. This detector possesses advantages such as high stability, low detection limit, high resolution, and low cost.

[0020] Compared with the prior art, the present invention has the following beneficial effects: (1) The all-inorganic perovskite thick film provided by the present invention has uniform size, good crystallinity, and high stability. Compared with the traditional vapor deposition method, the present invention utilizes the near-space sublimation method to carry out large-area extended deposition while growing at high throughput, thus preparing large-size thick films.

[0021] (2) This invention utilizes a buffer layer strategy to reduce the impact of thermodynamically driven island growth on the crystallization quality of the buried interface, effectively improving the interfacial bonding between the absorption layer and the substrate, and reducing the impact of pinholes, cracks, and peeling on thick film preparation. The high-quality absorption layer makes the prepared X-ray detector highly sensitive to X-rays, exhibiting a low detection limit and high resolution.

[0022] (3) The perovskite thick film preparation method based on near-space sublimation developed in this invention is highly operable and can prepare absorber layer thick films of tens to hundreds of micrometers according to specific requirements. The substrate temperature is controllable, which is beneficial for integration with existing silicon-based integrated circuit processes. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the near-space sublimation apparatus used in the preparation of all-inorganic perovskite thick films in this invention. Figure 2 SEM images of the perovskite films prepared in Example 1 and Comparative Example 1 are shown; where a and b are Comparative Example 1, and c and d are SEM images of the perovskite films in Example 1 with a buffer layer deposited for 10 min.

[0024] Figure 3 SEM images of the perovskite films with 3 / 5 / 15 min buffer layers prepared in Example 1; where a and b are the buffer layers deposited for 3 min in Example 1, c and d are the buffer layers deposited for 5 min in Example 1, and e and f are the buffer layers deposited for 15 min in Example 1.

[0025] Figure 4 The images show the PL and TRPL test results of the perovskite films with buffer layers prepared in Example 1 and Comparative Example 1 after 10 min of deposition.

[0026] Figure 5 The figures show the electrical performance test results of Example 2 and Comparative Example 2; where a represents Comparative Example 2 and c represents Example 2.

[0027] Figure 6 This is a thickness distribution diagram of the device prepared in Example 3.

[0028] Figure 7 The X-ray response statistics of the device prepared in Example 3 are shown in the figure.

[0029] Figure 8 This is a schematic diagram of the structure of the all-inorganic lead halide perovskite X-ray detector based on the near-space sublimation method of the present invention.

[0030] Figure 9 The detection limit test diagram is for the device in Example 1.

[0031] Figure 10 The image shows the storage stability test results for the device in Application Example 1.

[0032] Figure 11 The image shows the irradiation stability test results of the device in Example 1.

[0033] Figure 12 The diagram shows the bias stability test results for the device in Application Example 1.

[0034] Figure 13 The image shows the imaging test results of the device used in Example 2. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Modifications or equivalent substitutions made by those skilled in the art based on their understanding of the technical solutions of this invention, without departing from the spirit and scope of the invention, should be covered within the protection scope of this invention.

[0036] The raw materials used in the following specific embodiments were all purchased from the market and used directly without processing. The apparatus for preparing the all-inorganic perovskite absorber layer of this invention is as follows: Figure 1 As shown, a near-space sublimation process is employed. The precursor powder is placed in the evaporation zone, and the conductive substrate is placed in the deposition zone directly opposite the evaporation zone, maintaining a spacing of 6.5 cm. Deposition is carried out under a vacuum environment below 0.1 Pa. In the following specific embodiment, the precursor powder is processed by ball milling CsBr and PbBr2 powders according to a specific molar ratio at a speed of 300 rpm for 1 h. Subsequently, the mixture is placed in a sealed container under vacuum and sintered at 700 °C for 15 min to obtain the precursor powder.

[0037] Comparative Example 1 The perovskite precursor powder is a mixture of CsBr and PbBr2 in a molar ratio of 1.1:1, with a purity of over 99%. ITO glass is the preferred substrate. The perovskite layer is prepared using a near-space sublimation method. (1) Place the thoroughly cleaned and dried ITO glass in the deposition area; (2) The pretreated perovskite precursor powder is placed in a quartz boat and placed in the evaporation zone; (3) Close the furnace door and evacuate the vacuum to below 0.1 Pa. Start the heating program, heating the deposition zone and evaporation zone to 200℃ and 650℃ respectively, then hold for 5 min. Allow the chamber to cool naturally to room temperature and remove the sample. Observe its microstructure; SEM images are shown below. Figure 2 As shown in a and 2b, due to the rapid and disordered growth, small and irregular grains and pinholes caused by nucleation-growth mismatch are produced in the comparative samples. The PL and TRPL spectra at the buried interface of the obtained samples are as follows. Figure 4 As shown.

[0038] Example 1 The experimental apparatus and materials used in this embodiment are the same as those in Comparative Example 1. The preparation process is as follows: (1) Place the thoroughly cleaned and dried ITO glass in the deposition area; (2) The pretreated perovskite precursor powder is placed in a quartz boat and placed in the evaporation zone; (3) Close the furnace door and evacuate the vacuum to below 0.1 Pa. Start the heating program and heat the deposition zone and evaporation zone to 200℃ and 500℃ respectively, then hold for 3 / 5 / 10 / 15 min; (4) Keep the temperature of the deposition zone at 200℃, raise the temperature of the evaporation zone to 650℃, keep it at that temperature for 5 minutes, and let the chamber cool naturally to room temperature before taking out the sample.

[0039] Microscopic morphology SEM of products with a heat preservation time of 10 min, such as Figure 2 As shown in c and 2d, the microstructures of the products after heat preservation times of 3 min, 5 min, and 15 min are as follows. Figure 3 As shown, a and b represent buffer layers deposited for 3 minutes in Example 1, c and d represent buffer layers deposited for 5 minutes in Example 1, and e and f represent buffer layers deposited for 15 minutes in Example 1. Compared to Comparative Example 1, the introduction of the buffer layer leads to a significant change in grain orientation. The buffer layer synchronizes the nucleation process on the substrate surface, and as the buffer layer grows, the grains gradually form a highly consistent preferred orientation.

[0040] When the buffer layer growth time exceeds 5 min, significant grain merging occurs at the interface, marking the transformation of the morphology from a dispersed island structure to a continuous and dense film. However, extending the growth time to 15 min leads to excessive grain growth within the buffer layer, inhibiting lateral merging of the perovskite and resulting in small, unmerged grains remaining at the bottom. In contrast, a 10-min growth of the buffer layer resulted in uniform nucleation sites on the substrate surface, allowing for simultaneous lateral expansion and directional growth during rapid growth. This avoided competition among the buffer layer particles during growth, leading to large, uniform grains with nearly fused grain boundaries. The PL and TRPL spectra at the buried interface of the obtained samples are as follows... Figure 4 As shown. Compared to the perovskite film obtained in Comparative Example 1, the film in Example 1 has twice the PL strength and a PL lifetime increased by 36%. These results indicate improved crystal quality and a significant reduction in non-radiative recombination centers at the buried interface, confirming the in-situ regulatory effect of the buffer layer on the buried interface.

[0041] Comparative Example 2 (1) Place the thoroughly cleaned and dried ITO glass in the deposition area; (2) The pretreated perovskite precursor powder is placed in a quartz boat and placed in the evaporation zone; (3) Close the furnace door and evacuate the vacuum to below 0.1 Pa. Start the heating program and heat the deposition zone and evaporation zone to 200℃ and 650℃ respectively. Then keep them at these temperatures for 45 min. Allow the chamber to cool naturally to room temperature and remove the samples.

[0042] (4) An 80 nm chromium electrode was deposited on the surface of the perovskite layer by thermal evaporation.

[0043] The electrical performance of the device was evaluated. Figure 5 In Figure 'a', the dark current test of the device in Comparative Example 2 is performed under different bias conditions.

[0044] Example 2 (1) Place the thoroughly cleaned and dried ITO glass in the deposition area; (2) The pretreated perovskite precursor powder is placed in a quartz boat and placed in the evaporation zone; (3) Close the furnace door and evacuate the vacuum to below 0.1 Pa. Start the heating program and heat the deposition zone and evaporation zone to 200℃ and 500℃ respectively, then hold for 10 min; (4) Keep the temperature of the deposition zone at 200℃, raise the temperature of the evaporation zone to 650℃, keep it at that temperature for 45 min, and let the chamber cool naturally to room temperature before taking out the sample. (5) An 80 nm chromium electrode was deposited on the surface of the perovskite layer by thermal evaporation.

[0045] Compared to Figure 5 The device in section a exhibits significant noise fluctuations and dark current drift. Figure 5 The device in embodiment b exhibits a stable dark current, which is attributed to the lower defect density suppressing ion migration effects.

[0046] Example 3 (1) Thoroughly clean and dry a large-sized ITO (8×8 cm) 2 The glass is placed in the deposition zone; (2) The pretreated perovskite precursor powder is placed in a quartz boat and placed in the evaporation zone; (3) Close the furnace door and evacuate the vacuum to below 0.1 Pa. Start the heating program and heat the deposition zone and evaporation zone to 200℃ and 500℃ respectively, then hold for 10 min; (4) Keep the temperature of the deposition zone at 200℃, raise the temperature of the evaporation zone to 650℃, keep it at that temperature for 45 min, and after three cycles of deposition, allow the chamber to cool naturally to room temperature and take out the sample. (5) An 80 nm chromium electrode was deposited on the surface of the perovskite layer by thermal evaporation.

[0047] like Figure 6 As shown, by using a size of 8×8 cm 2 Thickness tests were conducted on a large-area thick film to evaluate its uniformity. Simultaneously, nine single-pixel devices uniformly distributed within the effective deposition area were tested. For example... Figure 7 As shown, these single-pixel devices exhibit highly consistent X-ray response, demonstrating that large-area thick-film devices not only possess excellent uniformity but also outstanding reliability and stability.

[0048] Application Example 1 A schematic diagram of the structure of the all-inorganic lead halide perovskite X-ray detector based on near-space sublimation developed in this invention is shown below. Figure 8 As shown in the diagram. 1 is the conductive substrate, 2 is the hole transport layer, 3 is the perovskite absorber layer, 4 is the electron transport layer, and 5 is the electrode.

[0049] (1) 40 nm NiO was sputtered onto a thoroughly cleaned and dried ITO glass surface using magnetron sputtering. x As a hole transport layer; (2) Place the treated substrate in the deposition area; (3) The pretreated perovskite precursor powder is placed in a quartz boat and placed in the evaporation zone; (4) Close the furnace door and evacuate the vacuum to below 0.1 Pa. Start the heating program and heat the deposition zone and evaporation zone to 200℃ and 500℃ respectively, then hold for 10 min; (5) Maintain the deposition zone temperature at 200℃, raise the evaporation zone temperature to 650℃, and hold for 45 min. After three cycles of deposition, allow the chamber to cool naturally to room temperature before removing the sample. (6) A PCBM electron transport layer was prepared on the surface of the perovskite layer by spin coating, wherein the PCBM was dissolved in toluene solution with a concentration of 30 mg / ml and annealed at 120℃ for 20 min after spin coating. (7) An 80 nm chromium electrode was deposited on the surface of the perovskite layer by thermal evaporation.

[0050] To enable specific X-ray detection applications, the thickness of the perovskite layer was increased to 100 μm. In Application Example 1, the introduction of a hole transport layer and an electron transport layer further improved the extraction efficiency of electrons and holes and suppressed the influence of electrode injection on dark current.

[0051] This application example demonstrates the X-ray response and stability of the all-inorganic perovskite X-ray detector of this invention, as detailed below: (1) The device's response to X-rays at different doses was tested, and the detection limit of the device was obtained by fitting the data. Figure 9 As shown. The detection limit of this device is 142.5 nGy. air s -1 This is approximately 5.5 μGy, the standard medical imaging dose rate. air s -1 One-fortieth.

[0052] (2) Store the device in a glove box filled with N2. Figure 10 The results showed that the dark current baseline remained stable after 165 days of storage, and the X-ray response did not decline.

[0053] (3) Figure 11 This demonstrates that the device exhibits excellent radiation stability under continuous X-ray irradiation (30.86 µGy). air s -1 Under these conditions, it can maintain a stable photocurrent for more than 3600 seconds.

[0054] (4) In terms of operational reliability, the detector exhibits minimal baseline drift during a 1200-second offset period, such as... Figure 12 As shown.

[0055] Application Example 2 The experimental setup, growth method and principle, and materials used in this application example are the same as those in application example 1. The difference is that the conductive substrate used is a TFT.

[0056] The thick film deposition process provided by this invention is scalable and fast, and the deposition temperature is low, making it compatible with TFT readout circuits. Figure 13 This study demonstrates the imaging application of an X-ray flat panel detector based on an all-inorganic perovskite thick film. The test results above indicate that the all-inorganic perovskite X-ray detector fabricated using this invention performs excellently in practical applications and has value for further research and application.

Claims

1. A method for preparing a lead halide perovskite absorber layer based on near-space sublimation, characterized in that, Including the following steps: Step 1: CsBr and PbBr2 powders are ball-milled and then sintered to obtain precursor powder; Step 2: In the near-space sublimation furnace, the precursor powder is loaded into a quartz boat and placed in the evaporation zone, and the conductive substrate is placed in the deposition zone. The distance between the evaporation zone and the deposition zone is 1-10 cm. After the chamber is evacuated, the temperature of the deposition zone is set to 100-200℃ and the temperature of the evaporation zone is set to 450-550℃. The constant temperature is maintained for 3-15 min. Step 3: Keep the temperature of the deposition zone constant, adjust the temperature of the evaporation zone to 575-675℃, and maintain the constant temperature for 5-45 minutes to obtain the lead halide perovskite absorber layer.

2. The method for preparing a lead halide perovskite absorber layer based on near-space sublimation according to claim 1, characterized in that, The molar ratio of CsBr to PbBr2 in the precursor powder is 0.9-1.9:

1.

3. The method for preparing a lead halide perovskite absorber layer based on near-space sublimation according to claim 1, characterized in that, In step 2, the chamber is evacuated to below 0.1 Pa.

4. The method for preparing a lead halide perovskite absorber layer based on near-space sublimation according to claim 1, characterized in that, In step 1, the ball milling speed is 300-400 rpm / min, and the mixing time is 10-60 min; In step 1, sintering is carried out at 675-750℃ for 10-20 min.

5. The method for preparing a lead halide perovskite absorber layer based on near-space sublimation according to claim 1, characterized in that, In step 2, the temperature of the evaporation zone is 480-530℃, and the constant temperature is maintained for 3-15 minutes.

6. The method for preparing a lead halide perovskite absorber layer based on near-space sublimation according to claim 1, characterized in that, It also includes the step of repeating step 3 to perform cyclic deposition to obtain a lead halide perovskite absorber layer with a thickness of 80-200 μm.

7. A lead halide perovskite absorber layer prepared by the preparation method according to any one of claims 1-6, based on near-space sublimation.

8. A thick-film X-ray detector made entirely of inorganic lead halide perovskite, characterized in that, Includes the lead halide perovskite absorber layer based on near-space sublimation as described in claim 7.

9. The all-inorganic lead halide perovskite thick-film X-ray detector according to claim 8, characterized in that, The X-ray detector includes a conductive substrate, a perovskite absorption layer, a hole transport layer, an electron transport layer, and a top electrode; The conductive substrate includes one of silicon wafer, ITO glass, FTO glass, and TFT; the perovskite absorber layer is the lead halide perovskite absorber layer based on near-space sublimation as described in claim 7; the hole transport layer includes PEDOT:PSS and NiO. x One or more of the following; the electron transport layer includes BCP, C 60 The material is one or more of SnO2 and PCBM; the top electrode is one or more of gold, copper, silver, chromium and aluminum.

10. The application of the all-inorganic lead halide perovskite thick-film X-ray detector according to claim 8 or 9 in X-ray detection.

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