Preparation method of three-dimensional confined secondary growth perovskite single crystal thin film X-ray detector

Abstract

The present invention discloses a method for preparing a three-dimensional confined secondary growth perovskite single crystal thin film X-ray detector, comprising: obtaining a substrate; preparing a SU-8 / PMMA layer on the substrate to obtain a SU-8 / PMMA / substrate base; removing the SU-8 / PMMA layer in multiple regions of the SU-8 / PMMA / substrate base to obtain multiple slit-shaped three-dimensional spaces; growing a perovskite single crystal array in the multiple slit-shaped three-dimensional spaces using a supersaturated MAPbI3 solution and a top covering scraper moving; removing the SU-8 / PMMA layer between the arrays, and growing the perovskite single crystal array again in the formed slit-shaped three-dimensional spaces to obtain a complete perovskite single crystal film; and preparing electrodes on the surface of at least one perovskite single crystal film to obtain an X-ray detector. The present invention can grow large-sized, high-quality perovskite single crystal films with uniform and controllable thickness, and prepare large-area, high-performance X-ray detectors.

Description

Technical Field

[0001] The present invention belongs to the technical field of perovskite X-ray detectors, and in particular relates to a method for preparing a three-dimensional restricted secondary growth perovskite single crystal thin film X-ray detector. Background Art

[0002] X-ray detection is a powerful tool used in medical diagnosis, non-destructive material testing, security inspections, and research. Perovskite, a novel optoelectronic material, has emerged as a rising star in the field due to its strong X-ray blocking capabilities, excellent carrier transport, high sensitivity, and low-cost manufacturing. Research suggests that perovskite-based materials hold promise for the development of a new generation of low-cost, high-performance X-ray detectors.

[0003] Perovskite materials possess a wide variety of micromorphologies, including single crystals, polycrystalline materials, and amorphous materials. Single crystals are further categorized as thin films, bulk single crystals, and low-dimensional nanocrystals. Perovskite materials with different morphologies exhibit significant differences in performance. Polycrystalline perovskites, due to their high dark current and difficulty maintaining thin film uniformity, are difficult to fabricate in X-ray detectors with low detection limits and high performance. Compared to polycrystalline materials, single crystal perovskites offer the advantages of no grain boundaries, low defects, and long carrier lifetimes, making them promising candidates for high-performance X-ray detectors.

[0004] Currently, the growth of perovskite single crystals primarily relies on solution growth techniques, including antisolvent vapor-assisted crystallization, inverse temperature crystallization, and solution cooling. These methods are time-consuming, typically requiring several days to obtain millimeter-scale single crystals. Furthermore, they struggle with directional growth of large, laterally sized single crystals, making them inadequate for the production of large-area, high-performance X-ray detectors.

[0005] Therefore, how to prepare high-quality perovskite single crystal films with large lateral size, uniform and controllable thickness has become a key issue in the current preparation of X-ray detectors. Summary of the Invention

[0006] To address the aforementioned problems in the prior art, embodiments of the present invention provide a method for preparing a three-dimensional confined secondary growth perovskite single crystal thin film X-ray detector and a three-dimensional confined secondary growth perovskite single crystal thin film X-ray detector. The specific technical solutions are as follows:

[0007] In a first aspect, an embodiment of the present invention provides a method for preparing a three-dimensional confined secondary growth perovskite single crystal thin film X-ray detector, comprising:

[0008] obtaining a substrate;

[0009] preparing a SU-8 / PMMA layer on the substrate to obtain a SU-8 / PMMA / substrate base;

[0010] removing the SU-8 / PMMA layer in multiple regions of the SU-8 / PMMA / substrate base to obtain multiple slit-shaped three-dimensional spaces;

[0011] In the plurality of slit-shaped three-dimensional spaces, a perovskite single crystal array is grown by using a supersaturated MAPbI3 solution and a top covering scraper moving;

[0012] removing the SU-8 / PMMA layer between the perovskite single crystal arrays and growing perovskite single crystals again in the multiple slit-shaped three-dimensional spaces formed to obtain a complete perovskite single crystal film;

[0013] Based on at least one layer of perovskite single crystal film, an X-ray detector is obtained by preparing electrodes on the surface.

[0014] In one embodiment of the present invention, the material of the substrate includes silicon, silicon dioxide, sapphire, FTO and ITO; and the substrate is ultrasonically cleaned in acetone, ethanol and deionized water in sequence.

[0015] In one embodiment of the present invention, the step of preparing a SU-8 / PMMA layer on the substrate to obtain a SU-8 / PMMA / substrate base comprises:

[0016] A PMMA layer is spin-coated on an ultrasonically cleaned substrate through a spin-coating process, an SU-8 layer is spin-coated after annealing, and an SU-8 / PMMA layer is obtained after annealing again. The SU-8 / PMMA layer and the substrate constitute a SU-8 / PMMA / substrate base.

[0017] In one embodiment of the present invention, removing the SU-8 / PMMA layer in multiple regions of the SU-8 / PMMA / substrate base to obtain multiple slit-shaped three-dimensional spaces includes:

[0018] Through a preset etching process, the SU-8 / PMMA layer in multiple areas of the SU-8 / PMMA / substrate base is removed to obtain multiple slit-shaped three-dimensional spaces whose length, width and height meet corresponding size requirements; wherein the preset etching process includes photolithography and ion beam etching.

[0019] In one embodiment of the present invention, the method of growing a perovskite single crystal array in the plurality of slit-shaped three-dimensional spaces by using a supersaturated MAPbI3 solution and moving a top covering scraper comprises:

[0020] The etched SU-8 / PMMA / substrate base is placed on a hot stage, sufficient supersaturated MAPbI3 solution is dripped into the multiple slit-shaped three-dimensional spaces, and a PDMS scraper is covered on the top of the supersaturated MAPbI3 solution. During the slow movement of the PDMS scraper, the solvent evaporates and the solute precipitates to obtain a perovskite single crystal array.

[0021] In one embodiment of the present invention, the process of removing the SU-8 / PMMA layer between the perovskite single crystal arrays and growing perovskite single crystals again in the multiple slit-shaped three-dimensional spaces formed to obtain a complete perovskite single crystal film comprises:

[0022] Soaking the perovskite single crystal array in chlorobenzene, removing the SU-8 / PMMA layer by dissolving the underlying PMMA layer, and obtaining a plurality of slit-shaped three-dimensional spaces for regrowth spaced apart in the perovskite single crystal array;

[0023] The entire substrate having the perovskite single crystal array and the multiple slit-shaped three-dimensional spaces for regrowth is placed on a hot stage, sufficient supersaturated MAPbI3 solution is dripped into the multiple slit-shaped three-dimensional spaces for regrowth, and a PDMS scraper is covered on the top of the supersaturated MAPbI3 solution. During the slow movement of the PDMS scraper, the solvent evaporates and the solute precipitates to obtain the regrowth of the perovskite single crystal, and the regrowth of the perovskite single crystal and the original perovskite single crystal array eventually constitute a complete perovskite single crystal film.

[0024] In one embodiment of the present invention, after obtaining a complete perovskite single crystal thin film, the method further comprises:

[0025] On the obtained layer of complete perovskite single crystal thin film, at least one layer of complete perovskite single crystal thin film is prepared again by growing a perovskite single crystal array twice.

[0026] In one embodiment of the present invention, a method for controlling the thickness of the perovskite single crystal film contained in the three-dimensional confined secondary growth perovskite single crystal film X-ray detector includes:

[0027] The heights of multiple slit-shaped three-dimensional spaces in forming a complete perovskite single crystal thin film are controlled, and / or the number of stacked layers of a complete perovskite single crystal thin film is controlled.

[0028] In one embodiment of the present invention, a method for controlling the quality of the perovskite single crystal film contained in the three-dimensional confined secondary growth perovskite single crystal film X-ray detector includes:

[0029] Control the width and thickness of multiple slit-shaped three-dimensional spaces in the formation of a complete perovskite single crystal film.

[0030] In a second aspect, an embodiment of the present invention provides a three-dimensional confined secondary growth perovskite single crystal thin film X-ray detector, which is prepared according to the method for preparing a three-dimensional confined secondary growth perovskite single crystal thin film X-ray detector according to the first aspect. The three-dimensional confined secondary growth perovskite single crystal thin film X-ray detector comprises, from bottom to top:

[0031] A substrate, a perovskite single crystal thin film layer located on the substrate, and an electrode located on the perovskite single crystal thin film layer.

[0032] Beneficial effects of the present invention:

[0033] In the method for preparing a three-dimensional confined secondary growth perovskite single crystal thin film X-ray detector provided by an embodiment of the present invention, a plurality of slit-shaped three-dimensional spaces are first formed on the prepared SU-8 / PMMA / Si substrate based on an etching process as fine channels for the growth of perovskite single crystals, and then a supersaturated MAPbI3 solution and a top covering scraper are moved to quickly evaporate and crystallize under the confinement of the slit-shaped three-dimensional space to form a perovskite single crystal array; then, the SU-8 / PMMA photoresist layer is removed to form a plurality of slit-shaped three-dimensional spaces again, which serve as new fine channels for the secondary growth of perovskite single crystals, thereby forming a complete perovskite single crystal thin film.

[0034] The embodiment of the present invention utilizes a three-dimensional restricted secondary growth method to induce directional movement of the precursor solution, increase the solute movement speed, control the solute crystallization speed in different directions, accelerate the directional horizontal crystallization of the solute, and solve the problem of limited and disordered mass transfer during the crystal growth process. The solute can be quickly and directionally replenished to the crystal nucleation position, so that the perovskite single crystal can grow over a large area with controllable thickness, grow a laterally large-sized perovskite single crystal array at one time, and then produce a complete large-area perovskite single crystal film through secondary growth. Therefore, this method can quickly grow laterally large-sized, uniformly thick, and high-quality perovskite single crystal films on different substrates, thereby producing large-area, low-cost, and high-performance X-ray detectors.

[0035] Furthermore, the embodiment of the present invention can control the thickness of the perovskite single crystal film in the perovskite single crystal film X-ray detector by controlling the height of multiple slit-shaped three-dimensional spaces in the formation of a complete perovskite single crystal film and the number of superimposed layers of a complete perovskite single crystal film. By controlling the width and thickness of multiple slit-shaped three-dimensional spaces in the formation of a complete perovskite single crystal film, the quality of the perovskite single crystal film in the perovskite single crystal film X-ray detector can be controlled. It can be seen that the three-dimensional confined secondary growth method provided by the embodiment of the present invention can quickly grow large-area, high-quality, thickness-controlled perovskite single crystal films, solving the problem that perovskite single crystal films are difficult to prepare on a large scale, and the control method is simple and effective. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 A schematic flow chart of a method for preparing a three-dimensional confined secondary growth perovskite single crystal thin film X-ray detector provided by an embodiment of the present invention;

[0037] Figure 2 A schematic diagram of a specific process of a method for preparing a three-dimensional confined secondary growth perovskite single crystal thin film X-ray detector provided by an embodiment of the present invention;

[0038] Figure 3 A schematic structural diagram of a three-dimensional confined secondary growth perovskite single crystal thin film X-ray detector provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0039] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0040] In order to achieve the purpose of preparing a high-quality perovskite single crystal film with large lateral size, uniform and controllable thickness, and thus preparing a large-area, high-performance X-ray detector, the embodiments of the present invention provide a method for preparing a three-dimensional confined secondary growth perovskite single crystal thin film X-ray detector and a three-dimensional confined secondary growth perovskite single crystal thin film X-ray detector.

[0041] Below, a method for preparing a three-dimensional confined secondary growth perovskite single crystal thin film X-ray detector provided by an embodiment of the present invention is first introduced.

[0042] like Figure 1 As shown, a method for preparing a three-dimensional confined secondary growth perovskite single crystal thin film X-ray detector provided by an embodiment of the present invention may include the following steps:

[0043] S1, obtain substrate;

[0044] For this step, see Figure 2 2a in.

[0045] In one optional embodiment, the substrate material includes silicon, silicon dioxide, sapphire, FTO (FTO conductive glass is fluorine-doped SnO2 transparent conductive glass (SnO2:F), referred to as FTO), and ITO (indium tin oxide); and the substrate is ultrasonically cleaned in acetone, ethanol, and deionized water, respectively. The ultrasonic cleaning time and ultrasonic power can be set as needed.

[0046] In an optional embodiment, the ultrasonic cleaning time is 5 to 15 minutes.

[0047] In an optional embodiment, the ultrasonic power is 60%-100%.

[0048] S2, preparing a SU-8 / PMMA layer on the substrate to obtain a SU-8 / PMMA / substrate base;

[0049] For this step, see Figure 2 2b in.

[0050] In an optional implementation manner, S2 may include the following steps:

[0051] A PMMA layer is spin-coated on an ultrasonically cleaned substrate through a spin-coating process, an SU-8 layer is spin-coated after annealing, and an SU-8 / PMMA layer is obtained after annealing again. The SU-8 / PMMA layer and the substrate constitute a SU-8 / PMMA / substrate base.

[0052] PMMA is polymethyl methacrylate, a high molecular weight polymer also known as acrylic or organic glass. SU-8 is a high-contrast, epoxy-based photoresist.

[0053] In an optional embodiment, the PMMA layer is spin-coated at a speed of 4000 rpm, a time of 60 s, and an annealing temperature of 90° C.; the SU-8 layer is spin-coated at a speed of 8000 rpm, a time of 60 s, and an annealing temperature of 90° C.

[0054] In an optional embodiment, the thickness of the obtained SU-8 / PMMA layer can be 5 μm, 10 μm, etc.

[0055] S3, removing the SU-8 / PMMA layer in multiple regions of the SU-8 / PMMA / substrate base to obtain multiple slit-shaped three-dimensional spaces;

[0056] For this step, see Figure 2 2c in.

[0057] In an optional implementation manner, S3 may include the following steps:

[0058] Through a preset etching process, the SU-8 / PMMA layer in multiple areas of the SU-8 / PMMA / Si substrate is removed to obtain multiple slit-shaped three-dimensional spaces whose length, width and height meet the corresponding size requirements; wherein the preset etching process includes photolithography and ion beam etching.

[0059] This step is to prepare a slit-shaped three-dimensional space for the growth of perovskite single crystals. Specifically, the areas where multiple SU-8 / PMMA layers are located can be intermittently etched on the SU-8 / PMMA / substrate base obtained in S2 by etching processes such as photolithography and ion beam etching until the corresponding substrate surface is exposed, thereby obtaining multiple slit-shaped three-dimensional spaces for the growth of perovskite single crystals. In addition, the length, width, and height of the multiple slit-shaped three-dimensional spaces can be controlled so that the dimensions in any direction meet the corresponding requirements to meet the needs of thickness control and quality control.

[0060] In an optional embodiment, the thickness of the photoresist used is 1-20 μm.

[0061] In an optional embodiment, the photolithography exposure time is 2 minutes.

[0062] In an optional embodiment, 98% ethyl lactate developer is used, and the developing time is 60 seconds.

[0063] In an optional embodiment, the length of the multiple slit-shaped three-dimensional spaces is 0.001-10 cm, the width is 1-1000 μm, and the height is 1-20 μm.

[0064] S4, growing a perovskite single crystal array in the plurality of slit-shaped three-dimensional spaces by using a supersaturated MAPbI3 solution and moving a top covering scraper;

[0065] For this step, see Figure 2 2d~2f in.

[0066] In an optional implementation manner, S4 may include the following steps:

[0067] The etched SU-8 / PMMA / substrate base is placed on a hot stage, sufficient supersaturated MAPbI3 solution is dripped into the multiple slit-shaped three-dimensional spaces, and a PDMS scraper is covered on the top of the supersaturated MAPbI3 solution. During the slow movement of the PDMS scraper, the solvent evaporates and the solute precipitates to obtain a perovskite single crystal array.

[0068] MAPbI3 is a perovskite. PDMS is polydimethylsiloxane, a type of silicone and a soft elastomer.

[0069] As a soft blade, the PDMS scraper always adheres to the etched SU-8 / PMMA / substrate base during movement, and the bottom surface of the soft blade can at least completely cover multiple slit-shaped three-dimensional spaces and tightly adhere to the surfaces of multiple slit-shaped three-dimensional spaces, so that a sealed space is formed between the bottom surface of the soft blade and the growth substrate. This can effectively avoid damage to the SU-8 / PMMA photoresist during operation and ensure that the supersaturated MAPbI3 solution is confined to the sealed space, which can prevent the perovskite precursor solution in the slit-shaped three-dimensional space array from evaporating and crystallizing. When the PDMS scraper moves from one end of the slit-shaped three-dimensional space array to the other end, because the substrate is heated, when the slit-shaped three-dimensional space array is exposed, the perovskite precursor solution therein quickly evaporates and crystallizes at the head of the PDMS scraper. Moreover, under the action of capillary force, the perovskite precursor solution will be continuously transported to the crystallization position to replenish the depleted solute for crystal growth. Therefore, as the PDMS scraper moves, the perovskite single crystal can continue to grow. It can be seen that using the above method, the precursor solution can be induced to move in a directional manner, the solute movement speed can be increased, the solute crystallization speed in different directions can be controlled, the directional horizontal crystallization of the solute can be accelerated, and the problem of limited and disordered mass transfer during crystal growth can be solved, so that the solute can be quickly and directionally replenished to the crystal nucleation position, thereby increasing the growth rate of perovskite single crystals.

[0070] Moreover, since the thickness direction of the perovskite single crystal is restricted by the PDMS scraper during the growth process, its thickness is limited, and the thickness of the entire grown perovskite single crystal is consistent, that is, the thickness of the perovskite single crystal depends on the height of multiple slit-shaped three-dimensional spaces, and the thickness can be uniform and controllable.

[0071] like Figure 2 As shown in Figure 2f, the multiple white areas on the substrate are the obtained perovskite single crystal arrays. It can be understood that this step is the first growth of the perovskite single crystal.

[0072] In an optional embodiment, the constant heating temperature on the hot stage is 100-250°C.

[0073] In an optional embodiment, the PDMS scraper is moved horizontally at a speed of 0.01-0.2 mm / s.

[0074] In an optional embodiment, the preparation process of the supersaturated MAPbI3 solution includes:

[0075] Take 254.4 mg of methylamine iodine MAI and 461.5 mg of lead iodide PbI2, add 1 mL of GBL solution (GBL Chinese name is γ-hydroxybutyric acid lactone), stir at 80°C, and then slowly cool to obtain a supersaturated solution of MAPbI3.

[0076] S5, removing the SU-8 / PMMA layer between the perovskite single crystal arrays, and growing perovskite single crystals again in the multiple slit-shaped three-dimensional spaces formed to obtain a complete perovskite single crystal film;

[0077] For this step, see Figure 2 2g~2k in.

[0078] In an optional implementation manner, S5 may include the following steps:

[0079] S51, soaking the perovskite single crystal array in chlorobenzene, removing the SU-8 / PMMA layer by dissolving the underlying PMMA layer, and obtaining a plurality of slit-shaped three-dimensional spaces for regrowth spaced apart in the perovskite single crystal array; this step is described in detail in the accompanying drawings. Figure 2 As shown in Figure 2g, the perovskite single crystal array produced by S4 is soaked in chlorobenzene, which dissolves the underlying PMMA layer to remove the SU-8 / PMMA layer. The remaining MAPbI3 single crystals are arranged in an array within the MAPbI3 / substrate. The gaps between the perovskite single crystal arrays, where the SU-8 / PMMA was removed, form multiple narrow 3D spaces, which can serve as narrow 3D spaces for the re-growth of perovskite single crystals.

[0080] In an optional embodiment, the perovskite single crystal array is immersed in chlorobenzene for 5 minutes to 60 minutes.

[0081] S52, placing the entire substrate having the perovskite single crystal array and the multiple slit-shaped three-dimensional spaces for regrowth on a hot stage, dripping sufficient supersaturated MAPbI3 solution into the multiple slit-shaped three-dimensional spaces for regrowth, and covering the top of the supersaturated MAPbI3 solution with a PDMS scraper, and obtaining regrowth of perovskite single crystals through solvent volatilization and solute precipitation during the slow movement of the PDMS scraper, and finally forming a complete perovskite single crystal film by the regrowth of the perovskite single crystal and the original perovskite single crystal array.

[0082] In an optional embodiment, the complete perovskite single crystal thin film is an all-inorganic perovskite or an organic-inorganic hybrid perovskite.

[0083] The process of obtaining the regrown perovskite single crystal in S52 is similar to the process of obtaining the first grown perovskite single crystal array in the previous text, and the process means are the same. It can be understood that this step is the second growth of the perovskite single crystal. Figure 2 As shown in 2j to 2k in FIG, the regrown perovskite single crystal and the original perovskite single crystal array will eventually form a complete perovskite single crystal film.

[0084] The preparation process of the supersaturated MAPbI3 solution is the same as that in S4. Therefore, sufficient supersaturated MAPbI3 solution can be prepared in advance for use in S4 and S5. Similarly, the constant heating temperature on the hot stage and the speed of the horizontal movement of the PDMS scraper can be the same as in S4.

[0085] It can be seen that the embodiment of the present invention obtains a perovskite single crystal thin film array through the primary growth of the perovskite single crystal; and then obtains a complete perovskite single crystal thin film through the secondary growth of the perovskite single crystal.

[0086] The inventors found during the research that if only a single layer of SU-8 glue is prepared on the substrate in S2, then Figure 2 In the steps 2h to 2g, a plurality of corresponding steps of slit-shaped three-dimensional spaces for re-growth are obtained. If the SU-8 photoresist is to be removed, whether hot acetone soaking or reactive ion etching is used, the quality of the already formed perovskite single crystal (i.e., the perovskite single crystal obtained by the first growth) will be seriously affected, and may even directly lead to the decomposition of the perovskite single crystal.

[0087] Therefore, in the embodiment of the present invention, PMMA / SU-8 double-layer photoresist is used in S2, and the SU-8 photoresist is removed in S5 by dissolving the PMMA under the SU-8 by immersing in chlorobenzene, which greatly reduces the impact on the perovskite single crystal.

[0088] S6, based on at least one layer of perovskite single crystal film, an electrode is prepared on the surface to obtain an X-ray detector.

[0089] In the embodiment of the present invention, an X-ray detector can be obtained by using a complete perovskite single crystal thin film obtained in S5 and preparing electrodes on the surface of the thin film.

[0090] The materials of the electrodes include gold, silver, copper, nickel, titanium, molybdenum and alloys, etc. For example, gold can be used to prepare Au electrodes, and the thickness can be 100 nm.

[0091] The preparation process of the electrode includes metal electron beam evaporation, metal sputtering, etc., and arrayed interdigitated electrode mask evaporation can also be used to prepare the electrode, etc., and no specific restrictions are made here.

[0092] In an optional embodiment, after obtaining a complete perovskite single crystal thin film, the method further comprises:

[0093] On the obtained layer of complete perovskite single crystal thin film, at least one layer of complete perovskite single crystal thin film is prepared again by growing a perovskite single crystal array twice.

[0094] In the embodiment of the present invention, one or more layers of perovskite single crystal thin films can be further grown on the surface of the complete perovskite single crystal thin film obtained in step S5 according to steps S2 to S5, and electrodes can be fabricated on the upper surface to obtain an X-ray detector. It is understood that the multilayer perovskite single crystal thin film can increase the total thickness of the perovskite single crystal thin film in the X-ray detector.

[0095] In an optional embodiment, a method for controlling the thickness of the perovskite single crystal film contained in the three-dimensional confined secondary growth perovskite single crystal film X-ray detector includes:

[0096] The heights of the multiple slit-shaped three-dimensional spaces in forming a complete perovskite single crystal thin film are controlled, and / or the number of superimposed layers of a complete perovskite single crystal thin film is controlled.

[0097] Specifically, the thickness of the perovskite single crystal film contained in the three-dimensional confined secondary growth perovskite single crystal thin film X-ray detector is controllable. The thickness of the perovskite single crystal film can be controlled by controlling the thickness of the photoresist spin coating to control the height of the slit-shaped three-dimensional space. Alternatively, a thicker perovskite single crystal film can be obtained by multiple secondary growths and stacked to increase the total thickness. The above two methods can be used alone or in combination, and can simultaneously meet the requirements of uniform and controllable thickness of the perovskite single crystal film. The thickness of the perovskite single crystal film contained in the three-dimensional confined secondary growth perovskite single crystal thin film X-ray detector can range from 0.05 to 500 μm.

[0098] In an optional embodiment, a method for controlling the quality of the perovskite single crystal film contained in the three-dimensional confined secondary growth perovskite single crystal film X-ray detector includes:

[0099] Control the width and thickness of multiple slit-shaped three-dimensional spaces in the formation of a complete perovskite single crystal film.

[0100] Specifically, a higher quality perovskite single crystal film can be obtained by controlling the width and thickness of the etched portion of the SU-8 / PMMA layer in S3.

[0101] The above control process can be set with reasonable parameters as needed, and no specific restrictions are made here.

[0102] Furthermore, since the quality of a complete perovskite single crystal film obtained in the embodiment of the present invention is independent of the area of ​​the substrate, a larger perovskite single crystal film can be produced by increasing the area of ​​the substrate. Therefore, the method of the embodiment of the present invention is capable of producing laterally large perovskite single crystal films.

[0103] Several specific embodiments are given below to illustrate the method for preparing a three-dimensional confined secondary growth perovskite single crystal thin film X-ray detector proposed in the embodiments of the present invention. (1) Specific embodiment 1

[0105] 1) If Figure 2 As shown in Figure 2a, a Si substrate was selected and ultrasonically cleaned in acetone, ethanol, and deionized water for 5-15 minutes in sequence.

[0106] 2) If Figure 2 As shown in Figure 2b, a SU-8 / PMMA layer was prepared;

[0107] Specifically, a PMMA layer is spin-coated on a cleaned Si substrate through a spin coating process, and then a SU-8 layer is spin-coated on the PMMA layer after annealing. After annealing, a SU-8 / PMMA layer is obtained to obtain a SU-8 / PMMA / Si substrate; wherein the thickness of the SU-8 / PMMA is 5 μm.

[0108] 3) If Figure 2 As shown in Figure 2c, multiple slit-shaped three-dimensional spaces are prepared for the growth of perovskite single crystals;

[0109] Specifically, the SU-8 / PMMA layer in multiple areas is etched away on the SU-8 / PMMA / Si substrate obtained in the previous step through processes such as photolithography and ion beam etching to obtain multiple slit-shaped three-dimensional spaces for the growth of perovskite single crystals; wherein the height of the multiple slit-shaped three-dimensional spaces is 5μm.

[0110] 4) If Figure 2 As shown in 2d-2f, a perovskite single crystal array is prepared;

[0111] Specifically, the SU-8 / PMMA / Si substrate etched in the previous step is first placed on a hot stage, and sufficient supersaturated MAPbI3 solution is dripped into the multiple slit-shaped three-dimensional spaces where the perovskite single crystal grows. The top of the solution is covered with a PDMS scraper. During the slow movement of the PDMS scraper, the solvent evaporates and the solute precipitates to obtain a perovskite single crystal array, namely, a MAPbI3 single crystal array.

[0112] 5) If Figure 2 As shown in Figure 2g, the SU-8 / PMMA layer is removed;

[0113] Specifically, the MAPbI3 single crystal array prepared in step 4) was soaked in chlorobenzene, and the SU-8 / PMMA layer was removed by dissolving the underlying PMMA layer. The remaining MAPbI3 single crystals were arranged in an array within the MAPbI3 / Si substrate. The gaps between the MAPbI3 single crystal arrays, where the SU-8 / PMMA had been removed, served as slit-like three-dimensional spaces for secondary growth of perovskite single crystals. The height of the slit-like three-dimensional spaces was 5 μm.

[0114] 6) If Figure 2 As shown in 2h-2k, a complete large-area perovskite single crystal film is prepared;

[0115] Specifically, the MAPbI3 / Si substrate prepared in step 5) is placed on a hot stage, and sufficient supersaturated MAPbI3 solution is dripped into the narrow three-dimensional space of the secondary growth of the perovskite single crystal. The top of the solution is covered with a PDMS scraper. During the slow movement of the PDMS scraper, the solvent evaporates and the solute precipitates to obtain a complete large-area MAPbI3 single crystal film, such as Figure 2 As shown in 2k.

[0116] 7) If Figure 2 As shown in Figure 2l, Au electrodes were prepared on complete large-area MAPbI3 single crystal films by metal electron beam evaporation, metal sputtering and other processes. (2) Specific embodiment 2

[0118] 1) Select a Si substrate and ultrasonically clean it in acetone, ethanol, and deionized water for 5-15 minutes.

[0119] 2) preparing a SU-8 / PMMA layer;

[0120] Specifically, a PMMA layer was spin-coated on a cleaned Si substrate through a spin coating process, and then a SU-8 layer was spin-coated on the PMMA layer after annealing. After annealing, a SU-8 / PMMA layer was obtained to obtain a SU-8 / PMMA / Si substrate; wherein the thickness of the SU-8 / PMMA layer was 10 μm.

[0121] 3) Prepare a slit-shaped three-dimensional space for the growth of perovskite single crystals;

[0122] Specifically, multiple regions of the SU-8 / PMMA layer are etched away on the SU-8 / PMMA / Si substrate obtained in the previous step through processes such as photolithography and ion beam etching to obtain a slit-shaped three-dimensional space for growing perovskite single crystals; wherein the height of the slit-shaped three-dimensional space is 10 μm.

[0123] 4) Preparation of perovskite single crystal arrays;

[0124] First, the etched SU-8 / PMMA / Si substrate is placed on a hot stage, and sufficient supersaturated MAPbI3 solution is dripped into the narrow three-dimensional space where the perovskite single crystal grows. The top of the solution is covered with a PDMS scraper. During the slow movement of the PDMS scraper, the solvent evaporates and the solute precipitates to obtain a MAPbI3 single crystal array.

[0125] 5) Remove the SU-8 / PMMA layer;

[0126] Specifically, the MAPbI3 single crystal array prepared in step 4) was soaked in chlorobenzene, and the SU-8 / PMMA layer was removed by dissolving the underlying PMMA layer. The remaining MAPbI3 single crystals were arranged in an array within the MAPbI3 / Si substrate. The gaps between the MAPbI3 single crystal arrays, where the SU-8 / PMMA had been removed, served as slit-like three-dimensional spaces for secondary growth of perovskite single crystals. The height of the slit-like three-dimensional spaces was 10 μm.

[0127] 6) Preparation of complete large-area perovskite single crystal thin films;

[0128] Specifically, the MAPbI3 / Si substrate prepared in step 5) is placed on a hot stage, and sufficient supersaturated MAPbI3 solution is dripped into the narrow three-dimensional space where the perovskite single crystal grows secondary. The top of the solution is covered with a PDMS scraper. During the slow movement of the PDMS scraper, the solvent evaporates and the solute precipitates to obtain a complete large-area MAPbI3 single crystal film.

[0129] 7) Repeated growth to prepare SU-8 / PMMA layer;

[0130] Specifically, a PMMA layer is spin-coated on the large-area perovskite single crystal film obtained in step 6) through a spin coating process, and then a SU-8 layer is spin-coated on the PMMA layer after annealing. After annealing, a SU-8 / PMMA layer is obtained to obtain a SU-8 / PMMA / MAPbI3 / Si substrate; wherein the thickness of the SU-8 / PMMA layer is 5 μm.

[0131] 8) Repeated growth to prepare a slit-shaped three-dimensional space for the growth of perovskite single crystals;

[0132] Specifically, a slit-shaped three-dimensional space for the growth of perovskite single crystals is obtained by etching away part of the SU-8 / PMMA layer on the SU-8 / PMMA / MAPbI3 / Si substrate obtained in the previous step through processes such as photolithography and ion beam etching, wherein the height of the slit-shaped three-dimensional space is 5 μm.

[0133] 9) Repeated growth to prepare perovskite single crystal arrays;

[0134] Specifically, the etched SU-8 / PMMA / MAPbI3 / Si substrate is first placed on a hot stage, and sufficient supersaturated MAPbI3 solution is dripped into the narrow three-dimensional space where the perovskite single crystal grows. The top of the solution is covered with a PDMS scraper. During the slow movement of the PDMS scraper, the solvent evaporates and the solute precipitates to obtain a MAPbI3 single crystal array.

[0135] 10) Repeat the growth and remove the SU-8 / PMMA layer;

[0136] Specifically, the MAPbI3 single crystal array prepared in step 9) was soaked in chlorobenzene to remove the SU-8 / PMMA layer by dissolving the underlying PMMA layer. The remaining MAPbI3 single crystals were arranged in an array within the MAPbI3 / Si substrate. The gaps between the MAPbI3 single crystal arrays, where the SU-8 / PMMA had been removed, served as slit-like three-dimensional spaces for secondary growth of perovskite single crystals. The height of the slit-like three-dimensional spaces was 5 μm.

[0137] 11) Repeated growth to prepare complete, thicker, and larger-area perovskite single crystal films;

[0138] Specifically, the MAPbI3 / Si substrate prepared in step 10) is placed on a hot stage, and sufficient supersaturated MAPbI3 solution is dripped into the narrow three-dimensional space of the secondary growth of the perovskite single crystal. The top of the solution is covered with a PDMS scraper. During the slow movement of the PDMS scraper, the solvent evaporates and the solute precipitates to obtain a complete, thicker, large-area MAPbI3 single crystal film.

[0139] 12) Prepare Au electrodes on complete large-area MAPbI3 single crystal films through metal electron beam evaporation, metal sputtering and other processes. (3) Specific embodiment three

[0141] 1) Select a Si substrate and ultrasonically clean it in acetone, ethanol, and deionized water for 5-15 minutes.

[0142] 2) preparing a SU-8 / PMMA layer;

[0143] Specifically, a PMMA layer was spin-coated on a cleaned Si substrate through a spin coating process, and then a SU-8 layer was spin-coated on the PMMA layer after annealing. After annealing, a SU-8 / PMMA layer was obtained to obtain a SU-8 / PMMA / Si substrate; wherein the thickness of the SU-8 / PMMA layer was 10 μm.

[0144] 3) Prepare a small three-dimensional space for the growth of perovskite single crystals;

[0145] Specifically, a portion of the SU-8 / PMMA layer is etched away on the SU-8 / PMMA / Si substrate obtained in the previous step through processes such as photolithography and ion beam etching to obtain a slit-shaped three-dimensional space for growing perovskite single crystals, wherein the height of the slit-shaped three-dimensional space is 10 μm.

[0146] 4) Preparation of perovskite single crystal arrays;

[0147] First, the etched SU-8 / PMMA / Si substrate is placed on a hot stage, and sufficient supersaturated MAPbI3 solution is dripped into the narrow three-dimensional space where the perovskite single crystal grows. The top of the solution is covered with a PDMS scraper. During the slow movement of the PDMS scraper, the solvent evaporates and the solute precipitates to obtain a MAPbI3 single crystal array.

[0148] 5) Remove the SU-8 / PMMA layer;

[0149] Specifically, the MAPbI3 single crystal array prepared in step 4) was soaked in chlorobenzene, and the SU-8 / PMMA layer was removed by dissolving the underlying PMMA layer. The remaining MAPbI3 single crystals were arranged in an array within the MAPbI3 / Si substrate. The gaps between the MAPbI3 single crystal arrays, where the SU-8 / PMMA had been removed, served as slit-like three-dimensional spaces for secondary growth of perovskite single crystals. The height of the slit-like three-dimensional spaces was 10 μm.

[0150] 6) Preparation of complete large-area perovskite single crystal thin films;

[0151] Specifically, the MAPbI3 / Si substrate prepared in step 5) is placed on a hot stage, and sufficient supersaturated MAPbI3 solution is dripped into the narrow three-dimensional space where the perovskite single crystal grows secondary. The top of the solution is covered with a PDMS scraper. During the slow movement of the PDMS scraper, the solvent evaporates and the solute precipitates to obtain a complete large-area MAPbI3 single crystal film.

[0152] 7) Through metal electron beam evaporation, metal sputtering and other processes, an arrayed interdigitated electrode mask is used to evaporate and prepare Au electrodes to produce a large-area arrayed perovskite X-ray detector.

[0153] It should be noted that, in the above three specific embodiments, the relationship between the steps is limited to the specific embodiments.

[0154] In the method for preparing a three-dimensional confined secondary growth perovskite single crystal thin film X-ray detector provided by an embodiment of the present invention, a plurality of slit-shaped three-dimensional spaces are first formed on the prepared SU-8 / PMMA / Si substrate based on an etching process as fine channels for the growth of perovskite single crystals, and then a supersaturated MAPbI3 solution and a top covering scraper are moved to quickly evaporate and crystallize under the confinement of the slit-shaped three-dimensional space to form a perovskite single crystal array; then, the SU-8 / PMMA photoresist layer is removed to form a plurality of slit-shaped three-dimensional spaces again, which serve as new fine channels for the secondary growth of perovskite single crystals, thereby forming a complete perovskite single crystal thin film.

[0155] The embodiment of the present invention utilizes a three-dimensional restricted secondary growth method to induce directional movement of the precursor solution, increase the solute movement speed, control the solute crystallization speed in different directions, accelerate the directional horizontal crystallization of the solute, and solve the problem of limited and disordered mass transfer during the crystal growth process. The solute can be quickly and directionally replenished to the crystal nucleation position, so that the perovskite single crystal can grow over a large area with controllable thickness, grow a laterally large-sized perovskite single crystal array at one time, and then produce a complete large-area perovskite single crystal film through secondary growth. Therefore, this method can quickly grow laterally large-sized, uniformly thick, and high-quality perovskite single crystal films on different substrates, thereby producing large-area, low-cost, and high-performance X-ray detectors.

[0156] Furthermore, the embodiment of the present invention can control the thickness of the perovskite single crystal film in the perovskite single crystal film X-ray detector by controlling the height of multiple slit-shaped three-dimensional spaces in the formation of a complete perovskite single crystal film and the number of superimposed layers of a complete perovskite single crystal film. By controlling the width and thickness of multiple slit-shaped three-dimensional spaces in the formation of a complete perovskite single crystal film, the quality of the perovskite single crystal film in the perovskite single crystal film X-ray detector can be controlled. It can be seen that the three-dimensional confined secondary growth method provided by the embodiment of the present invention can quickly grow large-area, high-quality, thickness-controlled perovskite single crystal films, solving the problem that perovskite single crystal films are difficult to prepare on a large scale, and the control method is simple and effective.

[0157] In a second aspect, an embodiment of the present invention further provides a three-dimensional confined secondary growth perovskite single crystal thin film X-ray detector, which is prepared according to the method for preparing a three-dimensional confined secondary growth perovskite single crystal thin film X-ray detector according to the first aspect, such as Figure 3 As shown, the three-dimensional confined secondary growth perovskite single crystal thin film X-ray detector includes, from bottom to top:

[0158] A substrate, a perovskite single crystal thin film layer located on the substrate, and an electrode located on the perovskite single crystal thin film layer.

[0159] For details, please refer to the method for preparing the three-dimensional confined secondary growth perovskite single crystal thin film X-ray detector provided in the first aspect, and will not be repeated here.

[0160] The embodiment of the present invention utilizes the proposed method for preparing a three-dimensional confined secondary growth perovskite single crystal thin film X-ray detector to produce a large-area, high-performance X-ray detector that meets various application requirements and has high application value.

[0161] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification.

[0162] The above description is only a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention are included in the scope of protection of the present invention.

Claims

1. A method for preparing a three-dimensional confined secondary growth perovskite single crystal thin film X-ray detector, characterized in that: include: obtaining a substrate; preparing a SU-8 / PMMA layer on the substrate to obtain a SU-8 / PMMA / substrate base; removing the SU-8 / PMMA layer in multiple regions of the SU-8 / PMMA / substrate base to obtain multiple slit-shaped three-dimensional spaces; In the plurality of slit-shaped three-dimensional spaces, a perovskite single crystal array is grown by using a supersaturated MAPbI3 solution and a top covering scraper moving; Removing the SU-8 / PMMA layer between the perovskite single crystal arrays, and regrowing perovskite single crystals in the multiple slit-shaped three-dimensional spaces formed to obtain a complete perovskite single crystal film; wherein, regrowing perovskite single crystals in the multiple slit-shaped three-dimensional spaces formed to obtain a complete perovskite single crystal film comprises: placing the entire substrate having the perovskite single crystal array and the multiple slit-shaped three-dimensional spaces for re-growth on a hot stage, dripping sufficient supersaturated MAPbI3 solution into the multiple slit-shaped three-dimensional spaces for re-growth, and covering the top of the supersaturated MAPbI3 solution with a PDMS scraper, obtaining regrown perovskite single crystals by solvent volatilization and solute precipitation during the slow movement of the PDMS scraper, and ultimately forming a complete perovskite single crystal film by the regrown perovskite single crystals and the original perovskite single crystal array; Based on at least one layer of perovskite single crystal film, an X-ray detector is obtained by preparing electrodes on the surface.

2. The method for preparing a three-dimensional confined secondary growth perovskite single crystal thin film X-ray detector according to claim 1, characterized in that: The materials of the substrate include silicon, silicon dioxide, sapphire, FTO and ITO; and the substrate is ultrasonically cleaned in acetone, ethanol and deionized water in sequence.

3. The method for preparing a three-dimensional confined secondary growth perovskite single crystal thin film X-ray detector according to claim 1, characterized in that: The method of preparing a SU-8 / PMMA layer on the substrate to obtain a SU-8 / PMMA / substrate base comprises: A PMMA layer is spin-coated on an ultrasonically cleaned substrate through a spin-coating process, an SU-8 layer is spin-coated after annealing, and an SU-8 / PMMA layer is obtained after annealing again. The SU-8 / PMMA layer and the substrate constitute a SU-8 / PMMA / substrate base.

4. The method for preparing a three-dimensional confined secondary growth perovskite single crystal thin film X-ray detector according to claim 1, characterized in that: The SU-8 / PMMA layer in multiple regions of the SU-8 / PMMA / substrate base is removed to obtain multiple slit-shaped three-dimensional spaces, including: Through a preset etching process, the SU-8 / PMMA layer in multiple areas of the SU-8 / PMMA / substrate base is removed to obtain multiple slit-shaped three-dimensional spaces whose length, width and height meet corresponding size requirements; wherein the preset etching process includes photolithography and ion beam etching.

5. The method for preparing a three-dimensional confined secondary growth perovskite single crystal thin film X-ray detector according to claim 4, characterized in that: The method of growing a perovskite single crystal array in the plurality of slit-shaped three-dimensional spaces by using a supersaturated MAPbI3 solution and moving a top covering scraper comprises: The etched SU-8 / PMMA / substrate base is placed on a hot stage, sufficient supersaturated MAPbI3 solution is dripped into the multiple slit-shaped three-dimensional spaces, and a PDMS scraper is covered on the top of the supersaturated MAPbI3 solution. During the slow movement of the PDMS scraper, the solvent evaporates and the solute precipitates to obtain a perovskite single crystal array.

6. The method for preparing a three-dimensional confined secondary growth perovskite single crystal thin film X-ray detector according to claim 5, characterized in that: The removing of the SU-8 / PMMA layer spaced apart from the perovskite single crystal array comprises: The perovskite single crystal array is immersed in chlorobenzene, and the SU-8 / PMMA layer is removed by dissolving the underlying PMMA layer, thereby obtaining a plurality of slit-shaped three-dimensional spaces for regrowth spaced apart in the perovskite single crystal array.

7. The method for preparing a three-dimensional confined secondary growth perovskite single crystal thin film X-ray detector according to claim 1, characterized in that: After obtaining a complete perovskite single crystal thin film, the method further comprises: On the obtained layer of complete perovskite single crystal thin film, at least one layer of complete perovskite single crystal thin film is prepared again by growing a perovskite single crystal array twice.

8. The method for preparing a three-dimensional confined secondary growth perovskite single crystal thin film X-ray detector according to any one of claims 1, 4, and 7, characterized in that: The method of controlling the thickness of the perovskite single crystal film contained in the three-dimensional confined secondary growth perovskite single crystal film X-ray detector includes: The heights of multiple slit-shaped three-dimensional spaces in forming a complete perovskite single crystal thin film are controlled, and / or the number of stacked layers of a complete perovskite single crystal thin film is controlled.

9. The method for preparing a three-dimensional confined secondary growth perovskite single crystal thin film X-ray detector according to any one of claims 1, 4, and 7, characterized in that: The method of controlling the quality of the perovskite single crystal film contained in the three-dimensional confined secondary growth perovskite single crystal film X-ray detector includes: Control the width and thickness of multiple slit-shaped three-dimensional spaces in the formation of a complete perovskite single crystal film.

10. A three-dimensional confined secondary growth perovskite single crystal thin film X-ray detector, characterized in that: The method for preparing a three-dimensional confined secondary growth perovskite single crystal thin film X-ray detector according to any one of claims 1 to 9 is prepared, wherein the three-dimensional confined secondary growth perovskite single crystal thin film X-ray detector comprises, from bottom to top: A substrate, a perovskite single crystal thin film layer located on the substrate, and an electrode located on the perovskite single crystal thin film layer.

Images