Two-dimensional RP type perovskite single crystal based on p-fluorobenzylamine bromide and preparation method and application thereof

Abstract

The invention discloses a two-dimensional RP type perovskite single crystal based on p-fluorobenzene methylamine bromide and a preparation method and application thereof, and the preparation method comprises the following steps: preparing a precursor solution, adding chlorobenzene into the precursor solution, heating and stirring until the precursor solution is fully dissolved; placing the precursor solution in a constant-temperature furnace for heat preservation, and then placing the precursor solution in an air dry oven for cooling to room temperature in stages; and volatilizing the precursor solution at room temperature until crystals are completely separated out, taking out the crystals, cleaning and drying. Chlorobenzene is added in the crystal preparation process to serve as an anti-solvent for crystallization, the solubility is reduced, the crystallization rate is delayed, diffusion control growth is achieved, large-size single crystal growth, grain boundary reduction and interface contact optimization are achieved by regulating and controlling crystallization kinetics, and the obtained perovskite material is low in defect state density, low in dark current drift and good in performance. When the material is used for preparing an X-ray detector, a device with higher conversion efficiency and more stable photocurrent response can be obtained.

Description

Technical Field

[0001] The present invention belongs to the technical field of perovskite single crystal X-ray radiation detection, and specifically relates to a two-dimensional RP-type perovskite single crystal based on p-fluorobenzylamine bromide. The present invention also relates to a preparation method of a two-dimensional RP-type perovskite single crystal based on p-fluorobenzylamine bromide. The present invention further relates to the application of a two-dimensional RP-type perovskite single crystal based on p-fluorobenzylamine bromide. Background Art

[0002] In recent years, two-dimensional perovskite materials have been applied in flexible, stretchable and bendable electronic or optoelectronic devices. The common two-dimensional perovskite materials are layered structures formed by inserting organic cations between inorganic octahedra. The relatively high environmental stability of two-dimensional metal halide perovskites compared to three-dimensional perovskites occupies an important position in semiconductor materials for detectors. The self-assembled growth of a layered structure with alternating organic cations and inorganic octahedral frameworks makes two-dimensional perovskites have a special electronic structure of quantum wells, resulting in physical properties such as anisotropic charge transport performance, high electrical conductivity and low defect density. The advantages compared to three-dimensional perovskites are as follows: Stability: Two-dimensional perovskites have better thermal and photo stability compared to three-dimensional perovskites. Due to the limitation of the two-dimensional structure, they can better resist degradation caused by heat and light, thus improving the long-term stability of the device; Optical properties: Two-dimensional perovskites usually have a high light absorption coefficient and a long exciton lifetime, which makes two-dimensional perovskites have a higher photoelectric conversion efficiency and response speed in optoelectronic devices; Carrier transport performance: The layered structure of two-dimensional perovskites is conducive to the transport and diffusion of carriers, thus improving the electrical conductivity and response speed of the device. This is particularly important for devices such as solar cells; Material design flexibility: The structure of two-dimensional perovskites can be regulated by reasonable design and synthesis methods to achieve optimization of optical and electrical properties; Preparation and processing convenience: Due to the characteristics of the two-dimensional structure, two-dimensional perovskites usually have a simpler preparation method and easier processability, which helps to reduce the preparation cost and improve the production efficiency of the device. Among two-dimensional perovskites, RP-type two-dimensional perovskites perform better in terms of photoelectric conversion efficiency and can achieve a higher photoelectric conversion efficiency. The optical properties of RP-type perovskites can be controlled by adjusting the structure and composition, and they have a high absorption coefficient and a long carrier lifetime. Due to the stability and performance advantages of RP-type two-dimensional perovskite materials, they have a wider application prospect in the fields of optoelectronic devices, photocatalysis, etc.

[0003] Organic-inorganic hybrid perovskite materials have high carrier mobility lifetime product and large resistance value. Because the core components of perovskite are elements such as Pb, Bi, I, and Br, their high average atomic number (Z ≥ 50) is guaranteed, and they have significantly higher X-ray absorption capacity than α-Se (atomic number 34). In addition, the energy band of perovskite is composed of antibonding orbits, which has defect tolerance characteristics. The low defect concentration ensures its high mobility and long carrier lifetime, showing excellent photoelectric properties such as high absorption coefficient, long exciton diffusion distance, high carrier mobility, and low exciton binding energy. It is precisely because organic-inorganic hybrid perovskite materials have so many excellent properties that they have broad prospects in the field of detectors. Low dark current and high signal-to-noise ratio indicate that there are few defects inside the single crystal. By adjusting the number of layers or composition (such as organic cations, metal / halogen ratio), the band gap can be optimized to adapt to different X-ray energy requirements. In medical imaging: low-dose high-sensitivity imaging to reduce patient radiation exposure. Industrial non-destructive testing: high-resolution detection of internal defects in materials. Security inspection and scientific research: Rapid response is suitable for dynamic imaging and high-energy physics experiments. Among organic-inorganic hybrid perovskite materials, two-dimensional RP-type perovskite single crystals have become cutting-edge materials in the field of X-ray detection due to their unique structure and optoelectronic properties.

[0004] However, when preparing two-dimensional RP-type perovskite materials, the nucleation process is usually difficult to control due to the rapid crystallization rate of the perovskite, which leads to a significant increase in vacancies, interstitials and grain boundary defects inside the crystal. The high defect density will reduce the carrier mobility and aggravate non-radiative recombination, limiting the photoelectric conversion efficiency of the detector. Summary of the invention

[0005] The purpose of the present invention is to provide a two-dimensional RP-type perovskite single crystal based on p-fluorobenzylamine bromide, which solves the problem of high defect density of existing perovskite single crystals.

[0006] Another object of the present invention is to provide a method for preparing a two-dimensional RP-type perovskite single crystal based on p-fluorobenzylamine bromide, which solves the problem that the crystallization speed of the existing preparation method is too fast, making the nucleation process difficult to control.

[0007] Another object of the present invention is to provide an application of a two-dimensional RP-type perovskite single crystal based on p-fluorobenzylamine bromide, which solves the problem of limited photoelectric conversion efficiency when the existing perovskite single crystal is used as an X-ray detector.

[0008] The first technical solution adopted by the present invention is: a method for preparing a two-dimensional RP-type perovskite single crystal based on p-fluorobenzylamine bromide, comprising the following steps: Step 1, weigh PF-PMABr and PbO powders and place them in a single crystal growth bottle, measure HBr and H3PO2 mixed solution, and add them into the single crystal growth bottle in sequence to obtain a precursor solution; Step 2: Add chlorobenzene to the precursor solution, heat it up and stir until it is completely dissolved; Step 3: Keep the precursor solution obtained in Step 2 in a constant-temperature furnace for heat preservation, and after completion, place it in a blast drying oven to cool down to room temperature in stages; Step 4: Let the precursor solution obtained in Step 3 volatilize at room temperature until crystals completely precipitate, take out the crystals, wash and dry them to obtain (P-F-PMA)2PbBr4 two-dimensional RP-type perovskite single crystals.

[0009] The characteristics of the first technical solution of the present invention also lie in that, In Step 1, the molar ratio of P-F-PMABr to PbO is 2:1, the volume ratio of HBr to H3PO2 is 7:3, and the concentration of the precursor solution is 1 mol / L.

[0010] In Step 2, the addition amount of chlorobenzene is 2% - 8% of the volume of the precursor solution obtained in Step 1.

[0011] In Step 2, the heating temperature is 90 - 120 °C, and the stirring duration is 30 - 45 min.

[0012] In Step 3, the heat preservation temperature of the constant-temperature furnace is 90 - 120 °C, and the heat preservation duration is 12 h; the staged cooling is specifically as follows: first cool at a rate of 0.2 - 2 °C / h until crystals start to precipitate, and then cool at a cooling rate of 0.1 - 0.5 °C / h to room temperature.

[0013] Step 4 is specifically as follows: Place the precursor solution on a 25 °C heating platform for 12 h, take out the crystals, wash them three times with acetone or chlorobenzene, and then dry them in a blast drying oven at a constant temperature of 30 °C for 12 h.

[0014] The second technical solution adopted by the present invention is: a two-dimensional RP-type perovskite single crystal based on p-fluorobenzylamine bromide, which is prepared by using the preparation method of the two-dimensional RP-type perovskite single crystal based on p-fluorobenzylamine bromide.

[0015] The third technical solution adopted by the present invention is: for the application of a two-dimensional RP-type perovskite single crystal based on p-fluorobenzylamine bromide, perform surface cleaning and polishing on the (P-F-PMA)2PbBr4 two-dimensional RP-type perovskite single crystal, and then evaporate and deposit interdigital gold electrodes with a thickness of 80 - 120 nm on the single crystal surface to prepare an X-ray detector.

[0016] The beneficial effects of the present invention are as follows: The present invention relates to a two-dimensional RP-type perovskite single crystal based on p-fluorobenzylamine bromide, its preparation method and application. By adding chlorobenzene as an anti-solvent during the crystal preparation process for crystallization, the solubility is reduced while the crystallization rate is delayed, achieving diffusion-controlled growth. By regulating the crystallization kinetics, large-sized single crystals are grown, the grain boundaries are reduced, and the interface contact is optimized. The obtained perovskite material has a low density of defect states and a low dark current drift. When used to prepare an X-ray detector, a device with a higher conversion efficiency and a more stable photocurrent response can be obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is the XRD pattern of the two-dimensional RP-type perovskite single crystal based on p-fluorobenzylamine bromide of the present invention; Figure 2 is the TEM image of the two-dimensional RP-type perovskite single crystal based on p-fluorobenzylamine bromide of the present invention; Figure 3 is the photoluminescence PL pattern of the two-dimensional RP-type perovskite single crystal based on p-fluorobenzylamine bromide of the present invention; Figure 4 is the ultraviolet-visible light absorption UV pattern of the two-dimensional RP-type perovskite single crystal based on p-fluorobenzylamine bromide of the present invention; Figure 5 is the I-V curve of the X-ray detector prepared from the two-dimensional RP-type perovskite single crystal based on p-fluorobenzylamine bromide of the present invention at different doses; Figure 6 is the photocurrent response stability pattern of the X-ray detector prepared from the two-dimensional RP-type perovskite single crystal based on p-fluorobenzylamine bromide of the present invention; Figure 7 is the structural diagram of the planar X-ray detector prepared from the two-dimensional RP-type perovskite single crystal based on p-fluorobenzylamine bromide of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0018] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0019] The present invention provides a method for preparing a two-dimensional RP-type perovskite single crystal based on p-fluorobenzylamine bromide, comprising the following steps: Step 1: Weigh p-fluorobenzylamine bromide (P-F-PMABr) and lead oxide (PbO) powders with a molar ratio of 2:1 and place them in a single crystal growth bottle. Measure a mixed solution of hydrobromic acid (HBr) and hypophosphorous acid (H3PO2) with a volume ratio of 7:3, and sequentially add it to the single crystal growth bottle to obtain a precursor solution, and the concentration of the precursor solution is 1 mol / L; Step 2: Add chlorobenzene accounting for 2% - 8% of the volume of the precursor solution. When first added, the chlorobenzene is located on the upper layer of the precursor solution. Then, heat it to 90 - 120 °C on a magnetic stirrer and stir for 30 - 45 min until it is fully dissolved. No stratification phenomenon of chlorobenzene in the precursor solution is observed. Step 3: Place the precursor solution obtained in Step 2 in a constant-temperature furnace at 90 - 120 °C and keep it for 12 h. After that, place it in a forced-air drying oven and first cool it at a rate of 0.2 - 2 °C / h until crystals start to precipitate (around 70 °C), and then cool it at a rate of 0.1 - 0.5 °C / h to room temperature (25 °C). Step 4: Place the precursor solution obtained in Step 3 on a heating table at 25 °C and keep it for 12 h to evaporate until the crystals are completely precipitated. Take out the crystals, wash them three times with acetone or chlorobenzene, and then dry them in a forced-air drying oven at a constant temperature of 30 °C for 12 h to obtain (P-F-PMA)2PbBr4 two-dimensional RP-type perovskite single crystals.

[0020] Through the above method, the present invention relates to a two-dimensional RP-type perovskite single crystal based on p-fluorobenzylamine bromide and its preparation method. By adding chlorobenzene as an antisolvent for crystallization during the crystal preparation process, while reducing the solubility, the crystallization rate is delayed, realizing diffusion-controlled growth, thereby reducing the defect density and inhibiting non-radiative recombination, and a device with higher conversion efficiency can be obtained. The present invention realizes the growth of large-size single crystals by regulating the crystallization kinetics, reduces grain boundaries and optimizes the interface contact, and the obtained perovskite material has a low density of defect states and a low dark current drift.

[0021] When preparing a planar perovskite X-ray detector in the present invention, the (P-F-PMA)2PbBr4 two-dimensional RP-type perovskite single crystal is subjected to surface cleaning and polishing treatment, and then an interdigitated gold electrode with a thickness of 80 - 120 nm is evaporated on the single crystal surface to prepare an X-ray detector with high conversion efficiency and stable photocurrent response.

[0022] Example 1 Step 1: Weigh powders of p-fluorobenzylamine bromide (P-F-PMABr) and lead oxide (PbO) with a molar ratio of 2:1 and place them in a single crystal growth bottle. Measure a mixed solution of hydrobromic acid (HBr) and hypophosphorous acid (H3PO2) with a volume ratio of 7:3 and add them to the single crystal growth bottle in sequence to obtain a precursor solution, and the concentration of the precursor solution is 1 mol / L. Step 2: Add chlorobenzene accounting for 2% of the volume of the precursor solution. When first added, the chlorobenzene is located on the upper layer of the precursor solution. Then, heat it to 90 °C on a magnetic stirrer and stir for 30 min until it is fully dissolved. No stratification phenomenon of chlorobenzene in the precursor solution is observed. Step 3: Place the precursor solution obtained in Step 2 in a constant-temperature furnace at 90 °C and keep it for 12 h. After completion, place it in a forced-air drying oven and first cool it at a rate of 0.2 °C / h until crystals start to precipitate (around 70 °C), and then cool it at a rate of 0.1 °C / h to room temperature of 25 °C; Step 4: Place the precursor solution obtained in Step 3 on a heating platform at 25 °C and keep it for 12 h to allow it to evaporate until crystals completely precipitate. Take out the crystals, wash them three times with acetone or chlorobenzene, and then place them in a forced-air drying oven at a constant temperature of 30 °C and dry them for 12 h to obtain (P-F-PMA)2PbBr4 two-dimensional RP-type perovskite single crystals.

[0023] Example 2 Step 1: Weigh powders of p-fluorobenzylamine bromide (P-F-PMABr) and lead oxide (PbO) with a molar ratio of 2:1 and place them in a single crystal growth bottle. Measure a mixed solution of hydrobromic acid (HBr) and hypophosphorous acid (H3PO2) with a volume ratio of 7:3, and add them to the single crystal growth bottle in sequence to obtain a precursor solution, and the concentration of the precursor solution is 1 mol / L; Step 2: Add chlorobenzene accounting for 8% of its volume to the precursor solution. When first added, the chlorobenzene is on the upper layer of the precursor solution. Then, heat it to 120 °C on a magnetic stirrer and stir for 45 min until it is fully dissolved, and no stratification phenomenon of chlorobenzene in the precursor solution is observed; Step 3: Place the precursor solution obtained in Step 2 in a constant-temperature furnace at 120 °C and keep it for 12 h. After completion, place it in a forced-air drying oven and first cool it at a rate of 2 °C / h until crystals start to precipitate (around 70 °C), and then cool it at a rate of 0.5 °C / h to room temperature (25 °C); Step 4: Place the precursor solution obtained in Step 3 on a heating platform at 25 °C and keep it for 12 h to allow it to evaporate until crystals completely precipitate. Take out the crystals, wash them three times with acetone or chlorobenzene, and then place them in a forced-air drying oven at a constant temperature of 30 °C and dry them for 12 h to obtain (P-F-PMA)2PbBr4 two-dimensional RP-type perovskite single crystals.

[0024] Example 3 Step 1: Weigh powders of p-fluorobenzylamine bromide (P-F-PMABr) and lead oxide (PbO) with a molar ratio of 2:1 and place them in a single crystal growth bottle. Measure a mixed solution of hydrobromic acid (HBr) and hypophosphorous acid (H3PO2) with a volume ratio of 7:3, and add them to the single crystal growth bottle in sequence to obtain a precursor solution, and the concentration of the precursor solution is 1 mol / L; Step 2: Add chlorobenzene accounting for 3% of its volume to the precursor solution. When first added, the chlorobenzene is on the upper layer of the precursor solution. Then, heat it to 95 °C on a magnetic stirrer and stir for 30 min until it is fully dissolved, and no stratification phenomenon of chlorobenzene in the precursor solution is observed; Step 3: Place the precursor solution obtained in Step 2 in a constant-temperature furnace at 95 °C and keep it for 12 h. After completion, place it in a blast drying oven and first cool it at a rate of 1.5 °C / h until crystals start to precipitate (around 70 °C), and then cool it at a rate of 0.4 °C / h to room temperature (25 °C); Step 4: Place the precursor solution obtained in Step 3 on a heating table at 25 °C and keep it for 12 h to allow it to evaporate until crystals completely precipitate. Take out the crystals, wash them three times with acetone or chlorobenzene, and then place them in a blast drying oven at a constant temperature of 30 °C and dry them for 12 h to obtain (P-F-PMA)2PbBr4 two-dimensional RP-type perovskite single crystals.

[0025] Example 4 Step 1: Weigh powders of p-fluorobenzylamine bromide (P-F-PMABr) and lead oxide (PbO) with a molar ratio of 2:1 and place them in a single crystal growth bottle. Measure a mixed solution of hydrobromic acid (HBr) and hypophosphorous acid (H3PO2) with a volume ratio of 7:3, and add them to the single crystal growth bottle in sequence to obtain a precursor solution, and the concentration of the precursor solution is 1 mol / L; Step 2: Add chlorobenzene accounting for 4% of its volume to the precursor solution. When first added, chlorobenzene is on the upper layer of the precursor solution. Then heat it to 100 °C on a magnetic stirrer and stir for 35 min until it is fully dissolved, and no layering phenomenon of chlorobenzene in the precursor solution is observed; Step 3: Place the precursor solution obtained in Step 2 in a constant-temperature furnace at 100 °C and keep it for 12 h. After completion, place it in a blast drying oven and first cool it at a rate of 0.5 °C / h until crystals start to precipitate (around 70 °C), and then cool it at a rate of 0.2 °C / h to room temperature (25 °C); Step 4: Place the precursor solution obtained in Step 3 on a heating table at 25 °C and keep it for 12 h to allow it to evaporate until crystals completely precipitate. Take out the crystals, wash them three times with acetone or chlorobenzene, and then place them in a blast drying oven at a constant temperature of 30 °C and dry them for 12 h to obtain (P-F-PMA)2PbBr4 two-dimensional RP-type perovskite single crystals.

[0026] Example 5 Step 1: Weigh powders of p-fluorobenzylamine bromide (P-F-PMABr) and lead oxide (PbO) with a molar ratio of 2:1 and place them in a single crystal growth bottle. Measure a mixed solution of hydrobromic acid (HBr) and hypophosphorous acid (H3PO2) with a volume ratio of 7:3, and add them to the single crystal growth bottle in sequence to obtain a precursor solution, and the concentration of the precursor solution is 1 mol / L; Step 2: Add chlorobenzene accounting for 5% of its volume to the precursor solution. When first added, chlorobenzene is on the upper layer of the precursor solution. Then heat it to 110 °C on a magnetic stirrer and stir for 40 min until it is fully dissolved, and no layering phenomenon of chlorobenzene in the precursor solution is observed; Step 3: Place the precursor solution obtained in Step 2 in a constant temperature furnace at 110 °C and keep it for 12 h. After completion, place it in a forced air drying oven and first cool it at a rate of 1.5 °C / h until crystals start to precipitate (around 70 °C), and then cool it at a cooling rate of 0.3 °C / h to room temperature (25 °C); Step 4: Place the precursor solution obtained in Step 3 on a 25 °C heating platform and keep it for 12 h to allow it to volatilize until crystals completely precipitate. Take out the crystals, wash them three times with acetone or chlorobenzene, and then place them in a forced air drying oven at a constant temperature of 30 °C and dry for 12 h to obtain (P-F-PMA)2PbBr4 two-dimensional RP-type perovskite single crystals.

[0027] Example 6 Step 1: Weigh powders of p-fluorobenzylamine bromide (P-F-PMABr) and lead oxide (PbO) with a molar ratio of 2:1 and place them in a single crystal growth bottle. Measure a mixed solution of hydrobromic acid (HBr) and hypophosphorous acid (H3PO2) with a volume ratio of 7:3, and add them to the single crystal growth bottle in sequence to obtain a precursor solution, and the concentration of the precursor solution is 1 mol / L; Step 2: Add chlorobenzene accounting for 6% of its volume to the precursor solution. When first added, the chlorobenzene is located on the upper layer of the precursor solution. Then, heat it to 115 °C on a magnetic stirrer and stir for 45 min until it is fully dissolved, and no layering phenomenon of chlorobenzene in the precursor solution is observed; Step 3: Place the precursor solution obtained in Step 2 in a constant temperature furnace at 115 °C and keep it for 12 h. After completion, place it in a forced air drying oven and first cool it at a rate of 2 °C / h until crystals start to precipitate (around 70 °C), and then cool it at a cooling rate of 0.5 °C / h to room temperature (25 °C); Step 4: Place the precursor solution obtained in Step 3 on a 25 °C heating platform and keep it for 12 h to allow it to volatilize until crystals completely precipitate. Take out the crystals, wash them three times with acetone or chlorobenzene, and then place them in a forced air drying oven at a constant temperature of 30 °C and dry for 12 h to obtain (P-F-PMA)2PbBr4 two-dimensional RP-type perovskite single crystals.

[0028] The present invention uses a low-temperature - cooling crystallization method and chlorobenzene as an anti-solvent to obtain different crystals of Examples 1 - 6 by changing the initial cooling value and the cooling rate, and obtains large-sized perovskite single crystals with high crystallinity and good crystal quality as shown by the XRD patterns. As Figure 1 shown in Figure 2 , 3 shown, with the help of transmission electron microscope TEM and PL photoluminescence spectrum tests, it shows that the two-dimensional perovskite has good crystallinity and excellent luminescence performance. As Figure 4 shown for ultraviolet - visible light absorption, there is a sharp peak in the range of 400 - 450 nm, indicating a strong exciton effect, which is related to the interlayer electron - hole confinement effect. Figure 5The I-V curves at different doses show that the two-dimensional perovskite material exhibits low dark current and high light responsiveness, which is consistent with its layered structure characteristics and is suitable for high-performance optoelectronic devices and radiation sensing applications. As Figure 6 shown, at a bias voltage of 10 V, the single-crystal detector maintains excellent response stability and has low dark current drift within 5000 s. Figure 7 Shown is a schematic diagram of a planar detector prepared by evaporating interdigitated gold electrodes on the surface of a single crystal.

Claims

1. Preparation method of two-dimensional RP-type perovskite single crystal based on p-fluorobenzylamine bromide, characterized in that, It includes the following steps: Step 1: Weigh P-F-PMABr and PbO powders and place them in a single crystal growth bottle. Measure the mixed solution of HBr and H3PO2, and add them to the single crystal growth bottle in sequence to obtain a precursor solution; Step 2: Add chlorobenzene to the precursor solution, heat it up and stir until it is fully dissolved; Step 3: Keep the precursor solution obtained in Step 2 in a constant temperature furnace for heat preservation. After completion, place it in a blast drying oven and cool it down to room temperature in stages; Step 4: Volatilize the precursor solution obtained in Step 3 at room temperature until the crystals completely precipitate. Take out the crystals, wash and dry them to obtain (P-F-PMA)2PbBr4 two-dimensional RP-type perovskite single crystals.

2. The preparation method of the two-dimensional RP-type perovskite single crystal based on p-fluorobenzylamine bromide according to claim 1, wherein, In Step 1, the molar ratio of P-F-PMABr to PbO is 2:1, the volume ratio of HBr to H3PO2 is 7:3, and the concentration of the precursor solution is 1 mol / L.

3. The preparation method of the two-dimensional RP-type perovskite single crystal based on p-fluorobenzylamine bromide according to claim 1, characterized in that, In Step 2, the addition amount of chlorobenzene is 2% - 8% of the volume of the precursor solution obtained in Step 1.

4. The preparation method of the two-dimensional RP-type perovskite single crystal based on p-fluorobenzylamine bromide as claimed in claim 1, wherein, In Step 2, the heating temperature is 90 - 120 °C, and the stirring time is 30 - 45 min.

5. The preparation method of the two-dimensional RP-type perovskite single crystal based on p-fluorobenzylamine bromide according to claim 1, wherein, In Step 3, the heat preservation temperature of the constant temperature furnace is 90 - 120 °C, and the heat preservation time is 12 h; the staged cooling is specifically: first cool it at a rate of 0.2 - 2 °C / h until the crystals start to precipitate, and then cool it at a rate of 0.1 - 0.5 °C / h to room temperature.

6. The preparation method of the two-dimensional RP-type perovskite single crystal based on p-fluorobenzylamine bromide according to claim 1, characterized in that, Step 4 is specifically: Place the precursor solution on a 25 °C heating platform for 12 h. Take out the crystals, wash them three times with acetone or chlorobenzene, and then dry them in a blast drying oven at a constant temperature of 30 °C for 12 h.

7. Two-dimensional RP-type perovskite single crystal based on p-fluorobenzylammonium bromide, characterized in that, It is prepared by using the preparation method of two-dimensional RP-type perovskite single crystal based on p-fluorobenzylamine bromide according to any one of claims 1 - 6.

8. Using the method of making an X-ray detector based on the two-dimensional RP-type perovskite single crystal of p-fluorobenzylamine bromide as described in claim 7, perform surface cleaning and polishing treatment on the two-dimensional RP-type perovskite single crystal of p-fluorobenzylamine bromide, and then evaporate an interdigital gold electrode with a thickness of 80 - 120 nm on the single crystal surface to prepare an X-ray detector.

9. The application of the two-dimensional RP-type perovskite single crystal of p-fluorobenzylamine bromide as described in claim 7, using the two-dimensional RP-type perovskite single crystal of p-fluorobenzylamine bromide to prepare an X-ray detector.

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