Large-size high-stable non-lead polar hybrid perovskite single crystal, preparation method and use thereof

Abstract

The application belongs to the technical field of functional crystal materials, and more particularly relates to a high-stability two-dimensional Dion-Jacobson type non-lead polar hybrid perovskite crystal and a preparation method and application thereof. The high-stability two-dimensional Dion-Jacobson type non-lead polar hybrid perovskite crystal has a chemical formula of (4AMPY)2AgBiBr8, belongs to a monoclinic system, and has a space group of P21. The crystal is prepared into an X-ray detector, which can realize efficient and stable X-ray detection under zero bias voltage and high bias voltage. The single crystal is irradiated by different X-ray irradiation doses, and the X-ray response performance thereof is tested. When the crystal is irradiated by different X-ray irradiation doses, the crystal exhibits obvious light response, and the result shows that the material has potential application value as an X-ray detection material.

Description

Technical Field

[0001] This invention belongs to the field of functional crystal materials technology, and more specifically relates to a highly stable two-dimensional Dion-Jacobson type lead-free polar hybrid perovskite crystal, its preparation method, and its applications. Background Technology

[0002] X-ray detection technology plays an indispensable role in aerospace, security inspection, and scientific research. Traditional X-ray detector materials mainly include silicon, which has weak X-ray absorption and significant attenuation. α Therefore, detectors built from materials like lead (Se) have relatively low performance and cannot fully meet current development needs. In recent years, hybrid perovskites have shown great potential in X-ray detection due to their strong X-ray absorption capabilities caused by the presence of heavy elements with high atomic numbers, such as lead and halogens (bromine (Br) and iodine (I)). Two-dimensional hybrid perovskites, in particular, have attracted significant attention due to their diverse structures and high designability. While significant progress has been made in X-ray detectors based on two-dimensional hybrid perovskites, structural instability leading to detector instability and the harmful effects of lead on the human body and the environment remain pressing challenges that need to be overcome.

[0003] Currently, there are several effective ways to improve the stability of materials, such as enhancing the interlayer interactions of organic layers through halogen substitution and hydroxyl substitution, and enhancing structural rigidity by substituting aliphatic amines with aromatic amines. This is because the abundant interactions in the structure, combined with the strong conjugation effect in aromatic amines, can effectively promote carrier transport, thereby improving the X-ray detection performance of the material.

[0004] Nevertheless, these materials still exhibit large interlayer spacing, which significantly inhibits efficient carrier transport in the detector. Furthermore, the inability of the organic components in most of these materials to be directly connected to the adjacent inorganic framework via strong hydrogen bonds is also a major reason for their reduced stability.

[0005] Recently, Dion-Jacobson hybrid perovskites constructed using diamines have attracted widespread attention due to their ability to significantly improve X-ray detection performance by linking organic components to the inorganic framework through strong hydrogen bonds and substantially reducing interlayer spacing. Replacing lead with monovalent metals (such as rubidium and silver) and trivalent metals (such as bismuth and antimony) can further reduce interlayer spacing and solve the problem of lead toxicity. However, unavoidable ion migration in hybrid perovskite materials remains a significant challenge, especially when the material is continuously driven by a high external electric field. Halogen vacancy-induced ion migration is particularly pronounced, with migrating ions accumulating at the electrode interface to form a space charge layer, causing a significant increase in dark current drift and baseline noise. Furthermore, the irreversible accumulation of migrating ions leads to lattice distortion, potentially causing structural collapse. Therefore, suppressing ion migration is crucial for improving material stability and achieving large-scale development. Recently, a self-powered detection mode without an external electric field has been shown to effectively suppress ion migration in hybrid perovskites. This detection mode requires materials to self-provide the built-in electric field needed for carrier separation and transport. Currently, the main materials that meet this requirement are polar materials and heterojunction materials, but the complex development process of heterojunction materials has slowed their progress in this field. Although Dion-Jacobson hybrid perovskite thin films (HA)2AgSbBr8 (HA being histamine) have been developed, they cannot be grown into large-sized single crystals with lower defect density, and they cannot be fabricated into high-performance self-powered X-ray detectors. Therefore, developing Dion-Jacobson type lead-free polar hybrid perovskite single crystals with high performance, high stability, and green, non-toxic properties to prepare X-ray detection materials, with the core focus on suppressing ion migration and promoting carrier transport efficiency, has become a pressing problem that needs to be solved by those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to provide a highly stable two-dimensional Dion-Jacobson type lead-free polar hybrid perovskite crystal, its preparation method, and its applications, in order to solve the problems existing in the prior art.

[0007] To achieve the above objectives, the present invention provides the following solution: One of the technical solutions of this invention is to provide a highly stable two-dimensional Dion-Jacobson type lead-free polar hybrid perovskite crystal. The chemical formula of this highly stable two-dimensional Dion-Jacobson type lead-free polar hybrid perovskite crystal is (4AMPY)2AgBiBr8, it belongs to the monoclinic crystal system, and its space group is [missing information]. P twenty one.

[0008] Furthermore, the cell parameters of the highly stable two-dimensional Dion-Jacobson type lead-free polar hybrid perovskite crystal are as follows:a =8.1525(4)Å, b =17.6969(9)Å, c =18.3283(8)Å, α =90°, β =101.716(4)°, γ =90°, V =2589.2(2)Å 3 , Z =4, density is 3.018 g / cm³ 3 .

[0009] The second technical solution of this invention provides a method for preparing the above-mentioned highly stable two-dimensional Dion-Jacobson type lead-free polar hybrid perovskite crystal, comprising the following steps: Using 4-methylaminopyridine (4AMPY), silver oxide, bismuth oxide and HBr as reactants, the highly stable two-dimensional Dion-Jacobson type lead-free polar hybrid perovskite crystal was obtained by heating and stirring the reaction, followed by crystallization and post-treatment.

[0010] Furthermore, the HBr is added in the form of an aqueous solution with a mass fraction of 40%-48%.

[0011] Furthermore, the molar ratio of 4-methylaminopyridine, silver oxide, bismuth oxide and HBr is 1.5:2:1:20-35, preferably 1.5:2:1:26.

[0012] Furthermore, the temperature of the heating and stirring reaction is 80-120℃, preferably 105℃.

[0013] Furthermore, the post-crystallization treatment steps include: after heating and stirring the reaction, placing it in an oven at 120°C, and slowly cooling the solution to 20-30°C using a slow cooling growth method, with a cooling rate of 1°C / day.

[0014] The third technical solution of the present invention provides an application of the above-mentioned highly stable two-dimensional Dion-Jacobson type lead-free polar hybrid perovskite crystal in the preparation of X-ray detectors.

[0015] The present invention discloses the following technical effects: The preparation method provided by this invention is simple and efficient, and can produce high-quality crystals. By controlling the reaction conditions, the growth of crystals can be optimized, thereby improving their stability and performance.

[0016] This invention provides a highly stable two-dimensional Dion-Jacobson type lead-free polar hybrid perovskite crystal. When fabricated into an X-ray detector, this crystal enables efficient and stable X-ray detection under both zero and high bias voltages. The X-ray response performance of the single crystal was tested by irradiating it with different X-ray doses. The crystal exhibited a significant photoresponse when irradiated with different X-ray doses, indicating its potential application value as an X-ray detection material. Attached Figure Description

[0017] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 The images show (4AMPY)2AgBiBr8 crystals prepared in Example 1 and Comparative Example 1, where a is Example 1 and b is Comparative Example 1.

[0018] Figure 2 This is a structural packing diagram of the (4AMPY)2AgBiBr8 crystal prepared in Example 1.

[0019] Figure 3 The image shows the XRD pattern of the (4AMPY)2AgBiBr8 crystal prepared in Example 1.

[0020] Figure 4 The UV-Vis absorption spectrum of the (4AMPY)2AgBiBr8 crystal prepared in Example 1 is shown.

[0021] Figure 5 The thermal stability decomposition curve of the (4AMPY)2AgBiBr8 crystal prepared in Example 1 is shown.

[0022] Figure 6 The nonlinear frequency doubling signal intensity of the (4AMPY)2AgBiBr8 crystal prepared in Example 1.

[0023] Figure 7 X-ray detection sensitivity of the (4AMPY)2AgBiBr8 crystal prepared in Example 1.

[0024] Figure 8 The X-ray detection limit of the (4AMPY)2AgBiBr8 crystal prepared in Example 1.

[0025] Figure 9 The dark current drift value is the value of the (4AMPY)2AgBiBr8 crystal prepared in Example 1.

[0026] Figure 10The stability of the (4AMPY)2AgBiBr8 crystal prepared in Example 1 was tested under high X-ray irradiation dose.

[0027] Figure 11 The initial detection sensitivity of the (4AMPY)2AgBiBr8 crystal prepared in Example 1 is compared with the sensitivity after three months. Detailed Implementation

[0028] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0029] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0030] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0031] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be readily apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0032] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0033] Unless otherwise specified, all raw materials and reagents involved in the specific embodiments of this invention are commercially available products.

[0034] Unless otherwise specified, room temperature and normal temperature in the specific embodiments of this invention refer to 20-30℃.

[0035] It should be noted that any aspects not described in detail in this invention are conventional practices in the field and are not the focus of this invention.

[0036] In some specific embodiments, the present invention provides a highly stable two-dimensional Dion-Jacobson type lead-free polar hybrid perovskite crystal with the chemical formula (4AMPY)2AgBiBr8 and the molecular formula C 12 H 20 AgBiBr8N4 belongs to the monoclinic crystal system and has space group 1. P 21, the unit cell parameters are: a =8.1525(4)Å, b =17.6969(9)Å, c =18.3283(8)Å, α =90°, β =101.716(4)°, γ =90°, V =2589.2(2)Å 3 , Z =4, density is 3.018 g / cm³ 3 .

[0037] 4AMPY stands for 4-methylaminopyridine.

[0038] The highly stable two-dimensional Dion-Jacobson type lead-free polar hybrid perovskite crystals provided in this invention are monoclinic and P The structural characteristics of the 21 polar space group help in understanding the symmetry and arrangement of crystals, which significantly influence their physical properties, such as optical and electrical properties. These parameters precisely define the crystal structure, aiding in the understanding of its physical and chemical properties. For example, a larger cell volume and suitable density contribute to enhanced crystal stability and X-ray absorption. In particular, the photovoltaic effect induced by spontaneous polarization in such polar single-crystal materials enables efficient carrier separation and transport spontaneously without an applied voltage, thus achieving highly efficient self-powered X-ray detection.

[0039] In some specific embodiments, the present invention provides a method for preparing highly stable two-dimensional Dion-Jacobson type lead-free polar hybrid perovskite crystals, the steps of which include: S1. Using 4-methylaminopyridine (4AMPY), silver oxide, bismuth oxide and HBr as reactants, the mixture was heated and stirred to obtain a light yellow clear solution. S2. The light yellow clear solution is subjected to crystallization post-treatment to obtain the highly stable two-dimensional Dion-Jacobson type lead-free polar hybrid perovskite crystal.

[0040] In some further formulations, the molar ratio of 4-methylaminopyridine, silver oxide, bismuth oxide, and HBr is 1.5:2:1:20-35. This molar ratio ensures complete reaction, optimizes crystal structure and properties, and improves crystal stability and X-ray absorption. The appropriate molar ratio of HBr ensures sufficient reaction while avoiding side reactions caused by excess HBr, and also improves crystal purity and quality.

[0041] In some further formulations, HBr is added in the form of an aqueous solution with a mass fraction of 40-48%. The concentration of 40-48% HBr aqueous solution is moderate, which can ensure the smooth progress of the reaction, while avoiding the corrosiveness and danger caused by excessively high concentrations.

[0042] In some further embodiments, the temperature for heating and stirring the reaction is 80-120°C. This temperature range ensures efficient reaction while avoiding side reactions and crystal structure damage caused by excessively high temperatures. Furthermore, appropriate temperatures can improve the growth quality and stability of the crystals.

[0043] In some further embodiments, the post-crystallization treatment step includes: placing the light yellow clear solution in an oven at 120°C and slowly cooling the solution to room temperature by a slow cooling growth method at a cooling rate of 1°C / day.

[0044] The slow-cooling growth method in this invention can produce crystals with larger sizes (millimeters and above), which are the only single crystals that meet the fabrication requirements for single-crystal X-ray detectors. Natural cooling is suitable for rapid fabrication of microcrystals, mainly used for determining crystal structure and basic characterization such as ultraviolet absorption, but it cannot be used to fabricate X-ray detectors. Both methods are suitable for different applications, and the slow-cooling growth method can further improve the quality and stability of the crystal.

[0045] The (4AMPY)2AgBiBr8 crystal prepared by the method of this invention uses inexpensive raw materials and has a simple synthesis process. Large-sized single crystals can be grown using a controlled cooling crystallization method. The chemical reaction formula is as follows: 4(4AMPY)+Ag2O+Bi2O3+8HBr→2(4AMPY)2AgBiBr8+4H2O.

[0046] This invention utilizes Ag + / Bi 3+(4AMPY)₂AgBiBr₈ was prepared by combining two lead-free metals with the aromatic diamine organic cation 4AMPY. This specific chemical composition enabled the (4AMPY)₂AgBiBr₈ crystal to form a Dion-Jacobson type structural framework, exhibiting high stability and excellent self-powered X-ray detection performance. The introduction of 4-methylaminopyridine not only induced the polarity of the crystal but also directly connected it to the inorganic framework through strong NH…Br hydrogen bonds, resulting in an extremely short interlayer spacing of only 3.09 Å. Furthermore, this shortened interlayer spacing and the 4AMPY aromatic diamine enhanced the interaction between the organic components and the inorganic framework, improving structural stability and facilitating carrier separation and transport efficiency.

[0047] Example 1 The preparation steps for highly stable two-dimensional Dion-Jacobson type lead-free polar hybrid perovskite crystals include: S1. Place 4-methylaminopyridine, silver oxide and bismuth oxide in a beaker at a molar ratio of 1.5:2:1, then add 48% HBr aqueous solution to the beaker, wherein the molar ratio of HBr in the silver oxide, bismuth oxide and HBr aqueous solution is 2:1:26. Heat to 105℃ and stir until the solution is a light yellow clear solution. S2. While the obtained light yellow clear solution is still hot, place it in a high-temperature oven at 120℃. By using a slow cooling growth method, the solution is slowly cooled to room temperature at a rate of 1℃ / day to obtain a highly stable two-dimensional Dion-Jacobson type lead-free polar hybrid perovskite crystal ((4AMPY)2AgBiBr8).

[0048] Comparative Example 1 The preparation steps for highly stable two-dimensional Dion-Jacobson type lead-free polar hybrid perovskite crystals include: S1. Place 4-methylaminopyridine, silver oxide and bismuth oxide in a beaker at a molar ratio of 1.5:2:1, then add 48% HBr aqueous solution to the beaker, wherein the molar ratio of HBr in the silver oxide, bismuth oxide and HBr aqueous solution is 2:1:26. Heat to 105℃ and stir until the solution is a light yellow clear solution. S2. The obtained light yellow clear solution was naturally cooled to room temperature to obtain yellow blocky microcrystals. After filtration and drying, a highly stable two-dimensional Dion-Jacobson type lead-free polar hybrid perovskite crystal ((4AMPY)2AgBiBr8) was obtained.

[0049] Test case Figure 1The images show photographs of (4AMPY)2AgBiBr8 crystals prepared in Example 1 and Comparative Example 1, where a represents Example 1 and b represents Comparative Example 1. As can be seen from the figures, the material prepared in Example 1 has a size of 3 mm × 2 mm × 1 mm, which is a large-size single crystal material, while the product prepared in Comparative Example 1 has a significantly smaller size than the product in Example 1.

[0050] X-ray single-crystal diffraction was performed on the (4AMPY)2AgBiBr8 crystal prepared in Example 1, and the results are as follows: The molecular formula of this compound is C2. 12 H 20 AgBiBr8N4 has the structural formula (4AMPY)2AgBiBr8, where 4AMPY represents 4-methylaminopyridine. At room temperature, (4AMPY)2AgBiBr8 crystals belong to the monoclinic crystal system, with space group [space group missing]. P 21. The unit cell parameters of the crystal are: a =8.1525(4)Å, b =17.6969(9)Å, c =18.3283(8)Å, α =90°, β =101.716(4)°, γ =90°, V =2589.2(2)Å 3 , Z =4, density is 3.018 g / cm³ 3 .

[0051] Figure 2 The figure shows the structural packing diagram of the (4AMPY)2AgBiBr8 crystal prepared in Example 1. As can be seen from the figure, (4AMPY)2AgBiBr8 has the following structure: the 4-methylaminopyridine organic cations in (4AMPY)2AgBiBr8 are neatly arranged in the interlayer, exhibiting a typical two-dimensional Dion-Jacobson type monolayer perovskite structure. Simultaneously, the 4-methylaminopyridine is directly connected to the AgBr6 / BiBr6 inorganic framework through strong NH…Br hydrogen bonds formed at both ends of the molecule. The crystal structure was simulated using Diamond software, yielding an interlayer spacing of 3.09 Å. This short interlayer spacing not only improves carrier transport efficiency but also eliminates van der Waals interactions between organic components through the formation of bilateral hydrogen bonds, thus resulting in higher structural stability.

[0052] Figure 3The image shows the XRD pattern of the (4AMPY)2AgBiBr8 crystal prepared in Example 1. As can be seen from the image, the phase purity of the (4AMPY)2AgBiBr8 crystal prepared in Example 1, as analyzed by X-ray powder diffraction, matches the results of the X-ray diffraction pattern obtained through structural simulation.

[0053] Figure 4 The image shows the UV-Vis absorption spectrum of the (4AMPY)₂AgBiBr₈ crystal prepared in Example 1. As can be seen from the figure, analysis of the optical absorption of (4AMPY)₂AgBiBr₈ prepared in Example 1 using UV-Vis absorption spectroscopy reveals that the absorption cutoff edge of (4AMPY)₂AgBiBr₈ is 527 nm. Based on the Tauc formula, the optical band gap of this compound can be derived as 2.45 eV.

[0054] Figure 5 The figure shows the thermal stability decomposition curve of the (4AMPY)2AgBiBr8 crystal prepared in Example 1. The thermogravimetric analysis results show that the decomposition temperature of (4AMPY)2AgBiBr8 is 574 K.

[0055] Figure 6 The figure shows the nonlinear frequency harmonic signal intensity of the (4AMPY)2AgBiBr8 crystal prepared in Example 1. Analysis of the nonlinear frequency harmonic signal of the (4AMPY)2AgBiBr8 crystal prepared in Example 1 indicates that the second-order nonlinear signal intensity of (4AMPY)2AgBiBr8 is 0.61 times that of potassium dihydrogen phosphate (KDP).

[0056] The (4AMPY)2AgBiBr8 crystal prepared in Example 1 was used to construct a single-crystal X-ray detector. The specific method was as follows: The selected samples have a volume of approximately 3×2×1 mm. 3 A high-quality single crystal is placed on a glass slide, and Ag electrodes are uniformly coated on both ends of the crystal (along the polar axis: crystallographic c-axis). Then, wires are led out from both ends to form a complete current path.

[0057] Figure 7 The figure shows the X-ray detection sensitivity of the (4AMPY)₂AgBiBr₈ crystal prepared in Example 1. As shown, the (4AMPY)₂AgBiBr₈ single-crystal X-ray detector exhibits excellent detection performance, with a power output of 661.4 μC Gy in self-powered mode. -1 cm -2 High detection sensitivity; the sensitivity increases sequentially with increasing bias voltage, reaching 9645.2 μC Gy at 100V. -1 cm-2 .

[0058] Figure 8 The figure shows the X-ray detection limit of the (4AMPY)2AgBiBr8 crystal prepared in Example 1. The figure also shows that the detection limit of the device in self-powered mode is as low as 12.3 nGy s. -1 It is for commercial use. α -Se (5500 nGy s -1 447 times that of ).

[0059] Figure 9 The figure shows the dark current drift value of the (4AMPY)₂AgBiBr₈ crystal prepared in Example 1. The figure indicates that the dark current drift value of the (4AMPY)₂AgBiBr₈ single-crystal X-ray detector is as low as 5.3 × 10⁻⁶ at a bias voltage of 100 V. -7 nA cm -1 s - 1 V -1 It can effectively suppress ion migration. Even after being placed under unencapsulated conditions for three months, its dark current drift value remains as low as 9.9 × 10⁻⁶. -7 nA cm -1 s -1 V -1 .

[0060] Figure 10 The stability of the (4AMPY)2AgBiBr8 crystal prepared in Example 1 was tested under high X-ray irradiation dose. The figure shows that the detector can operate stably for extended periods under high X-ray irradiation dose.

[0061] Figure 11 The figure compares the initial detection sensitivity of the (4AMPY)2AgBiBr8 crystal prepared in Example 1 with its sensitivity after three months. The figure shows that after three months of storage without vacuum sealing, the detector's sensitivity in self-powered detection mode still maintains over 97.5% of its initial efficiency.

[0062] Overall, the detector device prepared from the (4AMPY)2AgBiBr8 crystal provided by this invention exhibits excellent stability. This crystal demonstrates superior performance in the field of X-ray detection, such as high detection sensitivity, low detection limit, and high stability. These characteristics make it promising for broad applications in medical detection, security inspection, and scientific research.

[0063] This crystal exhibits strong X-ray absorption characteristics and high stability. Furthermore, its significant bulk photovoltaic effect induced by its polarity makes it highly promising for applications in self-powered direct X-ray detection. More importantly, its Dion-Jacobson structure and lead-free, non-toxic properties endow it with excellent stability and high safety. Therefore, this crystal holds promise for large-scale commercial development.

[0064] Finally, it should be noted that compared to devices constructed from thin-film materials, X-ray detectors based on single-crystal structures (single-crystal devices) have significantly fewer material defects due to the absence of obvious grain boundaries. This is one of the prerequisites for achieving high-performance X-ray detection. Furthermore, the interlayer spacing of the Dion-Jacobson type crystal material constructed using the 4AMPY diamine cation in this invention is much smaller than that of the (HA)₂AgSbBr₈ thin film. Also, because the atomic number of bismuth is greater than that of antimony, the X-ray absorption coefficient of the crystal material in this invention is significantly higher than that of the (HA)₂AgSbBr₈ thin film.

[0065] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0066] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A large-size, highly stable two-dimensional Dion-Jacobson type lead-free polar hybrid perovskite single crystal, characterized in that, The large-size, highly stable two-dimensional Dion-Jacobson type lead-free polar hybrid perovskite single crystal has the chemical formula (4AMPY)2AgBiBr8, belongs to the monoclinic crystal system, and has a space group of [missing information]. P twenty one.

2. The large-size, highly stable two-dimensional Dion-Jacobson type lead-free polar hybrid perovskite single crystal as described in claim 1, characterized in that, The cell parameters of the large-size, highly stable two-dimensional Dion-Jacobson type lead-free polar hybrid perovskite single crystal are as follows: a =8.1525(4)Å, b =17.6969(9)Å, c =18.3283(8)Å, α =90°, β =101.716(4)°, γ =90°, V =2589.2(2)Å 3 , Z =4, density is 3.018 g / cm³ 3 .

3. A method for preparing a large-size, highly stable two-dimensional Dion-Jacobson type lead-free polar hybrid perovskite single crystal as described in claim 1 or 2, characterized in that the step... include: Using 4-methylaminopyridine, silver oxide, bismuth oxide and HBr as reactants, the reaction was carried out by heating and stirring, followed by crystallization and treatment, to obtain the large-size, highly stable two-dimensional Dion-Jacobson type non-lead polar hybrid perovskite single crystal. The post-crystallization treatment employs a slow cooling growth method.

4. The preparation method according to claim 3, characterized in that, The HBr is added in the form of an aqueous solution with a mass fraction of 40-48%.

5. The preparation method according to claim 3, characterized in that, The molar ratio of 4-methylaminopyridine, silver oxide, bismuth oxide and HBr is 1.5:2:1:20-35.

6. The preparation method according to claim 5, characterized in that, The molar ratio of 4-methylaminopyridine, silver oxide, bismuth oxide and HBr is 1.5:2:1:

26.

7. The preparation method according to claim 3, characterized in that, The temperature for the heating and stirring reaction is 80-120℃.

8. The preparation method according to claim 7, characterized in that, The temperature for the heating and stirring reaction is 105°C.

9. The preparation method according to claim 3, characterized in that, The post-crystallization treatment steps include: after heating and stirring the reaction, placing it in an oven at 120°C, and slowly cooling the solution to 20-30°C using a slow cooling growth method, with a cooling rate of 1°C / day.

10. The application of a large-size, highly stable two-dimensional Dion-Jacobson type lead-free polar hybrid perovskite single crystal as described in claim 1 or 2 in the fabrication of an X-ray detector.

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