Rb3Sb2Br9 single crystal, growth method thereof and application of Rb3Sb2Br9 single crystal in X-ray detection

Abstract

The invention provides an Rb3Sb2Br9 single crystal, a growth method thereof and application of the Rb3Sb2Br9 single crystal in X-ray detection, and the growth method of the Rb3Sb2Br9 single crystal comprises the following steps: S1, reacting rubidium bromide with antimony bromide to obtain an Rb3Sb2Br9 polycrystal material; s2, putting the Rb3Sb2Br9 polycrystal material into a container, vacuumizing and sealing, and putting the Rb3Sb2Br9 polycrystal material into a crystal growth furnace; and S3, heating the high-temperature area, the medium-temperature area and the low-temperature area of the crystal growth furnace to preset temperatures of the temperature areas, moving the container to the high-temperature area to melt the Rb3Sb2Br9 polycrystal material in the container, and then gradually moving the container to the medium-temperature area and the low-temperature area to realize growth of the Rb3Sb2Br9 single crystal. According to the method, the high-quality Rb3Sb2Br9 single crystal can be grown, and an X-ray detector prepared from the Rb3Sb2Br9 single crystal has good X-ray detection performance at room temperature.

Description

Technical Field

[0001] The present invention belongs to the field of ionizing radiation detection, and particularly relates to an Rb3Sb2Br9 single crystal, a growth method thereof, and an application thereof in X-ray detection. Background Art

[0002] Room-temperature semiconductor radiation detection materials have important applications in the fields of homeland security, medical imaging, industrial inspection, and cosmic ray exploration. Therefore, it is of great significance to develop advanced room-temperature semiconductor radiation detection materials with excellent performance. An ideal room-temperature nuclear radiation detector should effectively identify low-dose radiation sources. To produce excellent spectral detection performance, it needs to meet a series of physical property requirements. The basic physical property requirements include: 1) a sufficiently wide bandgap to suppress dark current; 2) a high average atomic number ( Z ), and density (ρ) to achieve high photon blocking ability; 3) high defect tolerance and a low concentration of carrier trapping centers; 4) no polarization effect under long-term use; 5) high irradiation stability and chemical stability; 6) a high carrier mobility-lifetime product ( μτ ). Due to these physical property requirements, only a few compounds have been identified as potential semiconductor radiation detection materials. So far, semiconductor radiation detection materials with spectral performance include high-purity germanium (HPGe), CdZn 0.1 Te 0.9 (CZT), TlBr, and halide perovskites. The intrinsically narrow bandgap of HPGe makes it necessary to work under liquid nitrogen cooling, which limits its wide application. Intrinsic defects are easily generated during the growth of CZT crystals, such as Te inclusions and segregation. The ionic polarization in TlBr affects its stability, and TlBr has poor mechanical properties and is not easy to process. Halide perovskite materials have attracted attention in the field of ionizing radiation due to their excellent properties. CsPbBr3 crystals, as a typical representative of all-inorganic perovskites, have a suitable bandgap width, high resistivity, sensitive light response, high carrier mobility-lifetime product, and excellent stability. However, the lead in its composition has biological toxicity, which limits its large-scale application.

[0003] Rb3Sb2Br9-type all-inorganic perovskite has become a new generation of X-ray detection candidate material due to its lead-free characteristics, high effective atomic number ( Z eff >45), and high resistivity, etc., providing a new direction for solving the toxicity problem of lead-based perovskites. At present, the main growth method of Rb3Sb2Br9-type perovskite single crystals is the solution method, which is likely to cause element volatilization, not only polluting the environment, but also making it difficult to control the crystal composition and easy for the crystal to crack. Summary of the Invention

[0004] To solve the problems of the above-mentioned existing technologies, the present invention provides an Rb3Sb2Br9 single crystal, a growth method thereof, and an application in X-ray detection. The present invention can grow high-quality Rb3Sb2Br9 single crystals, and the X-ray detector prepared from the Rb3Sb2Br9 single crystal has good X-ray detection performance at room temperature.

[0005] The present invention is achieved through the following technical solutions: In a first aspect, the present invention provides a method for growing an Rb3Sb2Br9 single crystal, including: S1, reacting rubidium bromide and antimony bromide to prepare an Rb3Sb2Br9 polycrystalline material; S2, loading the Rb3Sb2Br9 polycrystalline material into a container, evacuating and sealing the container, and then loading it into a crystal growth furnace; the crystal growth furnace sequentially includes a high-temperature zone, a medium-temperature zone, and a low-temperature zone from one end to the other end; S3, heating and raising the temperature of the high-temperature zone, medium-temperature zone, and low-temperature zone of the crystal growth furnace to the preset temperature of each zone, moving the container containing the Rb3Sb2Br9 polycrystalline material to the high-temperature zone to melt the Rb3Sb2Br9 polycrystalline material in the container, and then gradually moving the container containing the Rb3Sb2Br9 polycrystalline material to the medium-temperature zone and the low-temperature zone to realize the growth of the Rb3Sb2Br9 single crystal; wherein, the preset temperature of the high-temperature zone is 600-750 °C, the preset temperature of the medium-temperature zone is 450-600 °C, and the preset temperature of the low-temperature zone is 200-450 °C; S4, after the growth is completed, cooling to room temperature to obtain the Rb3Sb2Br9 single crystal.

[0006] Preferably, S1 is specifically: mixing and grinding rubidium bromide and antimony bromide, placing the obtained mixture in a container, evacuating and sealing the container, and then performing sintering to obtain the Rb3Sb2Br9 polycrystalline material.

[0007] Further, the sintering process is: raising the temperature to 500-650 °C, holding for 24-36 h, and then cooling to room temperature.

[0008] Further, during the sintering process, the heating time is 12-16 h, and the cooling time is 16-24 h.

[0009] Preferably, pre-tests are conducted to obtain the temperatures at different positions from one end to the other end of the crystal growth furnace at the preset temperatures in each temperature zone, and a relationship curve between temperature and position is obtained; the freezing point temperature of the Rb3Sb2Br9 polycrystalline material is obtained through differential thermal analysis testing, and the position where the freezing point temperature is located is obtained according to the relationship curve between temperature and position; in S3, when the container filled with the Rb3Sb2Br9 polycrystalline material gradually moves from the high-temperature zone to the medium-temperature zone and the low-temperature zone, the moving speed in the high-temperature zone is 5-8 mm / h, and when it moves to the position where the freezing point temperature is located, the moving speed is adjusted to 0.2-0.5 mm / h.

[0010] Preferably, in S4, the cooling time is 48-120 h.

[0011] In a second aspect, the present invention provides an Rb3Sb2Br9 single crystal obtained by the growth method as described above.

[0012] In a third aspect, the present invention provides an X-ray detector including the Rb3Sb2Br9 single crystal as described above.

[0013] In a fourth aspect, the present invention provides a preparation method of the X-ray detector as described above, including: (1) successively grinding, polishing, cleaning, and drying the Rb3Sb2Br9 single crystal; (2) depositing metal electrodes on the Rb3Sb2Br9 single crystal obtained in step (1) to fabricate a three-layer structure of metal electrode - perovskite single crystal - metal electrode.

[0014] In a fourth aspect, the present invention provides the application of the Rb3Sb2Br9 single crystal or the X-ray detector as described above in X-ray detection.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The present invention adopts a specific growth method. First, a pure-phase Rb3Sb2Br9 polycrystalline material is obtained using rubidium bromide (RbBr) and antimony tribromide (SbBr3) as raw materials, and then it is loaded into a crystal growth furnace for melting and crystal growth. Since the polycrystalline material is sealed in the crystal growth furnace and a slow descending rate and cooling rate are adopted, it effectively inhibits the component deviation caused by raw material volatilization, etc., and this method is beneficial to the discharge of impurities during the crystal growth process, avoiding crystal cracking. The obtained single crystal has a large size, high purity, and good transparency, and has more excellent performance compared with the single crystal grown by the solution method. Compared with the solution method for growing single crystals, the method of the present invention can seal the raw materials in the crystal growth furnace, reducing the leakage and pollution caused by volatilization, making it easy to control the crystal composition; the operation is simple and easy to realize programmed growth.

[0016] The X-ray detector based on Rb3Sb2Br9 of the present invention has high resistivity, low dark current, and good X-ray photocurrent response. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0018] Figure 1 It is a schematic structural diagram of a three-temperature-zone Bridgman furnace; Figure 2 It is an X-ray powder diffraction pattern of the powder sample of the Rb3Sb2Br9 ingot grown in Example 1; Figure 3 In (a) is the Rb3Sb2Br9 single crystal grown in Example 1; (b) is a physical diagram of the prepared X-ray detection device; Figure 4 It is a single crystal grown in Comparative Example 1 at a speed of 1.2 mm / h near the freezing point; Figure 5 It is a single crystal grown in Comparative Example 2 at a speed of 0.8 mm / h near the freezing point; Figure 6 It is for the I - V characteristics of the X-ray detector based on the Rb3Sb2Br9 single crystal grown in Example 1; Figure 7 In (a) is the X-ray ON / OFF photocurrent response of the X-ray detector at different dose rates; (b) is the relationship between the photocurrent density generated by X-rays and the dose rate of the X-ray detector at different bias voltages. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] The following illustrates the embodiments of the present invention through specific specific examples. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0020] It should be noted that the process equipment or devices not specifically noted in the following embodiments all adopt conventional equipment or devices in the art.

[0021] It should be noted that the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units does not have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices. Moreover, unless otherwise specified, the numbering of each method step is only a convenient tool for identifying each method step, rather than limiting the arrangement order of each method step or the scope in which the present invention can be implemented. Changes or adjustments to their relative relationships, without substantial changes in the technical content, should also be regarded as the scope in which the present invention can be implemented.

[0022] The method for growing the Rb3Sb2Br9 single crystal according to the present invention includes: S1, reacting rubidium bromide and antimony bromide to prepare an Rb3Sb2Br9 polycrystalline material; S2, loading the Rb3Sb2Br9 polycrystalline material into a container, evacuating and sealing the container, and then loading it into a crystal growth furnace; the crystal growth furnace is sequentially a high-temperature zone, a medium-temperature zone, and a low-temperature zone from one end to the other end; S3, heating and raising the temperature of the high-temperature zone, medium-temperature zone, and low-temperature zone of the crystal growth furnace to the preset temperature of each zone, moving the container containing the Rb3Sb2Br9 polycrystalline material to the high-temperature zone to melt the Rb3Sb2Br9 polycrystalline material in the container, and then gradually moving the container containing the Rb3Sb2Br9 polycrystalline material from the high-temperature zone to the medium-temperature zone and the low-temperature zone to achieve the growth of the Rb3Sb2Br9 single crystal; wherein, the preset temperature of the high-temperature zone is 600 - 750 °C, the preset temperature of the medium-temperature zone is 450 - 600 °C, and the preset temperature of the low-temperature zone is 200 - 450 °C; S4, cooling to room temperature after growth is completed to obtain the Rb3Sb2Br9 single crystal.

[0023] In some embodiments of the present invention, S1 is specifically: mixing and grinding rubidium bromide and antimony bromide, placing the obtained mixture in a container, evacuating and sealing the container, and then sintering to obtain the Rb3Sb2Br9 polycrystalline material.

[0024] Specifically, the sintering is carried out in a single-temperature zone tube furnace, and the sintering process is: raising the temperature to 500 - 650 °C, the heating time is 12 - 16 h, keeping the temperature for 24 - 36 h, and then cooling to room temperature, the cooling time is 16 - 24 h.

[0025] In some embodiments of the present invention, through pre - testing, the temperatures at different positions from one end to the other end of the crystal growth furnace are obtained at the preset temperatures in each temperature zone, and a relationship curve between temperature and position is obtained; the freezing point temperature of the Rb3Sb2Br9 polycrystalline material is obtained through differential thermal analysis testing, and the position where the freezing point temperature is located is obtained according to the relationship curve between temperature and position; in S3, when the container filled with the Rb3Sb2Br9 polycrystalline material gradually moves from the high - temperature zone to the medium - temperature zone and the low - temperature zone, the moving speed in the high - temperature zone is 5 - 8 mm / h, and when it moves to the position where the freezing point temperature is located, the moving speed is adjusted to 0.2 - 0.5 mm / h. The length of the high - temperature zone is 350 - 450 mm, the medium - temperature zone is 80 - 120 mm, and the low - temperature zone is 130 - 170 mm. In the high - temperature zone, the moving speed of the container is relatively fast, which can shorten the overall process time, while near the freezing point, the descending moving speed is relatively slow, which can enable the single crystal to grow fully.

[0026] In some embodiments of the present invention, in S4, the cooling time is 48 - 120 h.

[0027] In the present invention, the container can be made of quartz tube, and the crystal growth furnace adopts a three - zone Bridgman furnace ( Figure 1 ). The three - zone Bridgman furnace includes three independent heating devices, a quartz furnace tube, a rotating and descending mechanism, and a temperature control module. The three independent heating devices surround the quartz furnace tube, and form a high - temperature zone, a medium - temperature zone, and a low - temperature zone from top to bottom in sequence. The heating devices all adopt spiral - wound nickel - chromium alloy resistance wires. The three heating devices are wrapped with a heat - insulating layer, and the heat - insulating layer is composed of mullite heat - insulating bricks and aluminosilicate fiber felts.

[0028] In the three - zone Bridgman furnace adopted in the embodiments of the present invention, the lengths of each temperature zone are: the high - temperature zone is 400 mm, the medium - temperature zone is 100 mm, and the low - temperature zone is 150 mm.

[0029] The rotating and descending mechanism consists of a quartz tube support that can rotate axially in the vertical direction and a translation stage mechanism that can precisely control the up - and - down movement. The quartz furnace tube is installed on the quartz tube support, and the quartz tube support can rotate around its central axis to ensure that the raw material is uniformly heated during the melting and crystal growth processes. The translation stage mechanism is driven by a stepping motor and a lead screw to move up and down in the vertical direction. The quartz tube support slowly descends with the translation stage mechanism at a set speed, thereby realizing the continuous growth of the crystal. The rotating and descending mechanism is also equipped with a position sensor and a speed controller to ensure the precise control of the descending speed and rotating speed of the quartz tube support (accuracy ± 0.01 mm).

[0030] The temperature control module includes multiple temperature sensors and their control units. The temperature sensors are distributed in the high-temperature zone, medium-temperature zone, low-temperature zone, and inside the quartz furnace tube, and are used to monitor the furnace temperature in real time. Three independent heating devices are equipped with a PID closed-loop temperature control system (accuracy ± 0.1 °C). According to the preset temperature curve and the temperature data feedback by the temperature sensors, the power of the heating devices is automatically adjusted to achieve precise temperature control. In addition, it has an overheat protection function. When the temperature inside the quartz furnace tube exceeds the set safety range, the heating power is automatically cut off to prevent equipment damage and safety accidents. The temperature sensor installed inside the quartz furnace tube can monitor the temperature at the tip position of the vacuum quartz tube in real time. This temperature data can intuitively reflect the growth status of the crystal inside the quartz furnace tube. With the help of this temperature data, the growth parameters can be adjusted, and then the growth of high-quality crystals can be achieved. The temperature at different positions from one end to the other end of the crystal growth furnace is pre-tested using the temperature sensor installed inside the quartz furnace tube, and the relationship curve between temperature and position is obtained. According to the relationship curve between temperature and position, the position where the solidification point temperature of the Rb3Sb2Br9 polycrystalline material is located is obtained.

[0031] When growing crystals, the quartz tube is placed inside the quartz furnace tube, and aluminosilicate fiber felt is used to fill the space between the quartz tube and the quartz furnace tube. Here, the aluminosilicate fiber felt not only has a heat preservation effect but also plays a role in fixing the quartz tube, supporting the quartz tube to prevent it from tipping and slipping.

[0032] The Rb3Sb2Br9 single crystal obtained by the growth method of the present invention can be used as an X-ray detection material for preparing an X-ray detector for X-ray detection.

[0033] The preparation method of the X-ray detector of the X-ray detector includes: (1) The Rb3Sb2Br9 single crystal is successively polished, polished, cleaned, and dried; (2) Metal electrodes are deposited on the Rb3Sb2Br9 single crystal obtained in step (1) to produce a three-layer structure of metal electrode - perovskite single crystal - metal electrode.

[0034] Example 1 The growth method of the Rb3Sb2Br9 single crystal includes the following steps: (1) The heating device is turned on to heat the high-temperature zone, medium-temperature zone, and low-temperature zone of the three-zone Bridgman furnace. The temperature of each zone is 660 °C in the high-temperature zone, 530 °C in the medium-temperature zone, and 430 °C in the low-temperature zone. The temperature at different positions from top to bottom of the three-zone Bridgman furnace is tested using the temperature sensor installed inside the quartz furnace tube, and the relationship curve between temperature and position is obtained.

[0035] (2)Weigh the raw materials of RbBr and SbBr3 according to the molar ratio of 3:2, place them in a mortar, mix evenly and grind thoroughly, transfer them to a quartz tube, evacuate to 10 -5 Pa and seal it, and carry out sintering. The sintering process is as follows: Heat it to 650 °C in 12 h, keep it warm for 24 h, and cool it to room temperature in 16 h to obtain a pure-phase Rb3Sb2Br9 polycrystalline material. The freezing point temperature of this Rb3Sb2Br9 polycrystalline material is obtained by differential thermal analysis as 464 °C, and the position where the freezing point temperature of the Rb3Sb2Br9 polycrystalline material is located is obtained according to the temperature-position relationship curve in step (1).

[0036] (3)Take the pure-phase Rb3Sb2Br9 polycrystalline material and put it into a quartz tube, evacuate to 10 -5 Pa and seal it, and then put it into the quartz furnace tube of a three-zone Bridgman furnace.

[0037] (4)Turn on the heating device to heat the high-temperature zone, medium-temperature zone, and low-temperature zone of the three-zone Bridgman furnace. The temperature of each zone is 660 °C in the high-temperature zone, 530 °C in the medium-temperature zone, and 430 °C in the low-temperature zone. After the temperature is stable, move the quartz tube containing the Rb3Sb2Br9 polycrystalline material upward to the high-temperature zone so that the quartz tube is located in the high-temperature zone. After the Rb3Sb2Br9 polycrystalline material is fully melted, lower the quartz tube containing the Rb3Sb2Br9 polycrystalline material at a speed of 8 mm / h. When it drops to the position where the freezing point temperature of the Rb3Sb2Br9 polycrystalline material is located, adjust the dropping speed to 0.4 mm / h. As the quartz tube drops, single crystal growth occurs. After the growth is completed, cool the furnace temperature to room temperature in 120 h to obtain an Rb3Sb2Br9 single crystal.

[0038] Comparative Example 1 (1)Weigh the raw materials of RbBr and SbBr3 according to the molar ratio of 3:2, place them in a mortar, mix evenly and grind thoroughly, transfer them to a quartz tube, evacuate to 10 -5 Pa and seal it, and carry out sintering. The sintering process is as follows: Heat it to 650 °C in 12 h, keep it warm for 24 h, and cool it to room temperature in 16 h to obtain a pure-phase Rb3Sb2Br9 polycrystalline material.

[0039] (2)Take the pure-phase Rb3Sb2Br9 polycrystalline material and put it into a quartz tube, evacuate to 10 -5 Pa and seal it, and then put it into the quartz furnace tube of a three-zone Bridgman furnace.

[0040] (3) Turn on the heating device to heat the high-temperature zone, medium-temperature zone, and low-temperature zone of the three-zone Bridgman furnace. The temperature of each zone is 660 °C for the high-temperature zone, 530 °C for the medium-temperature zone, and 430 °C for the low-temperature zone. After the temperature stabilizes, move the quartz tube containing the Rb3Sb2Br9 polycrystalline material upward to the high-temperature zone so that the quartz tube is located in the high-temperature zone. After the Rb3Sb2Br9 polycrystalline material is fully melted, lower the quartz tube containing the Rb3Sb2Br9 polycrystalline material at a speed of 8 mm / h. When it descends to the position where the solidification point temperature of the Rb3Sb2Br9 polycrystalline material is located, adjust the descent speed to 1.2 mm / h. As the quartz tube descends, single crystal growth occurs. After the growth is completed, lower the furnace temperature to room temperature over 120 h to obtain the Rb3Sb2Br9 single crystal.

[0041] Comparative Example 2 (1) Weigh the raw materials of RbBr and SbBr3 according to a molar ratio of 3:2, place them in a mortar, mix evenly and grind thoroughly, transfer them to a quartz tube, evacuate to 10 -5 Pa and seal it, and carry out sintering. The sintering process is as follows: heat up to 650 °C in 12 h, keep the temperature for 24 h, and cool down to room temperature in 16 h to obtain the pure-phase Rb3Sb2Br9 polycrystalline material.

[0042] (2) Take the pure-phase Rb3Sb2Br9 polycrystalline material and put it into a quartz tube, evacuate to 10 -5 Pa and seal it, and then put it into the quartz furnace tube of the three-zone Bridgman furnace.

[0043] (3) Turn on the heating device to heat the high-temperature zone, medium-temperature zone, and low-temperature zone of the three-zone Bridgman furnace. The temperature of each zone is 660 °C for the high-temperature zone, 530 °C for the medium-temperature zone, and 430 °C for the low-temperature zone. After the temperature stabilizes, move the quartz tube containing the Rb3Sb2Br9 polycrystalline material upward to the high-temperature zone so that the quartz tube is located in the high-temperature zone. After the Rb3Sb2Br9 polycrystalline material is fully melted, lower the quartz tube containing the Rb3Sb2Br9 polycrystalline material at a speed of 8 mm / h. When it descends to the position where the solidification point temperature of the Rb3Sb2Br9 polycrystalline material is located, adjust the descent speed to 0.8 mm / h. As the quartz tube descends, single crystal growth occurs. After the growth is completed, lower the furnace temperature to room temperature over 120 h to obtain the Rb3Sb2Br9 single crystal.

[0044] Example 2 The method for growing Rb3Sb2Br9 single crystal includes the following steps: (1) Turn on the heating device to heat the high-temperature zone, medium-temperature zone, and low-temperature zone of the three-zone Bridgman furnace. The temperature of each zone is 600 °C for the high-temperature zone, 450 °C for the medium-temperature zone, and 220 °C for the low-temperature zone. Use the temperature sensor set inside the quartz furnace tube to measure the temperatures at different positions from top to bottom of the three-zone Bridgman furnace to obtain the relationship curve between temperature and position.

[0045] (2) Weigh the raw materials of RbBr and SbBr3 according to the molar ratio of 3:2, place them in a mortar, mix evenly and grind thoroughly, transfer them to a quartz tube, evacuate to 10 -5 Pa and seal it, and carry out sintering. The sintering process is as follows: Heat it to 500 °C in 12 h, keep it at this temperature for 30 h, and cool it to room temperature in 20 h to obtain polycrystalline material of pure-phase Rb3Sb2Br9. The freezing point temperature of this Rb3Sb2Br9 polycrystalline material is obtained by differential thermal analysis test as 463 °C, and the position where the freezing point temperature of the Rb3Sb2Br9 polycrystalline material is located is obtained according to the temperature-position relationship curve in step (1).

[0046] (3) Put the pure-phase Rb3Sb2Br9 polycrystalline material into a quartz tube, evacuate to 10 -5 Pa and seal it, and then put it into the quartz furnace tube of a three-zone Bridgman furnace.

[0047] (4) Turn on the heating device to heat the high-temperature zone, medium-temperature zone, and low-temperature zone of the three-zone Bridgman furnace. The temperature of each zone is 600 °C in the high-temperature zone, 450 °C in the medium-temperature zone, and 220 °C in the low-temperature zone. After the temperature is stable, move the quartz tube containing the Rb3Sb2Br9 polycrystalline material upward to the high-temperature zone so that the quartz tube is located in the high-temperature zone. After the Rb3Sb2Br9 polycrystalline material is fully melted, lower the quartz tube containing the Rb3Sb2Br9 polycrystalline material at a speed of 7 mm / h. When it drops to the position where the freezing point temperature of the Rb3Sb2Br9 polycrystalline material is located, adjust the dropping speed to 0.4 mm / h. As the quartz tube drops, single crystal growth occurs. After the growth is completed, cool the furnace temperature to room temperature in 50 h to obtain Rb3Sb2Br9 single crystal.

[0048] Example 3 The method for growing Rb3Sb2Br9 single crystal includes the following steps: (1) Turn on the heating device to heat the high-temperature zone, medium-temperature zone, and low-temperature zone of the three-zone Bridgman furnace. The temperature of each zone is 650 °C in the high-temperature zone, 500 °C in the medium-temperature zone, and 200 °C in the low-temperature zone. Use the temperature sensors set in the quartz furnace tube to test the temperatures at different positions from top to bottom of the three-zone Bridgman furnace to obtain the temperature-position relationship curve.

[0049] (2) Weigh the raw materials of RbBr and SbBr3 according to the molar ratio of 3:2, place them in a mortar, mix evenly and grind thoroughly, transfer them to a quartz tube, evacuate to 10 -5Combine RbBr and SbBr₃ in a molar ratio of 3:2, place them in a mortar, mix evenly and grind thoroughly, transfer to a quartz tube, evacuate to 10

[0050] Pa and seal it, then sinter it. The sintering process is as follows: Heat it to 550 °C over 15 h, hold for 36 h, and cool to room temperature over 20 h to obtain a pure-phase Rb₃Sb₂Br₉ polycrystalline material. The freezing point temperature of this Rb₃Sb₂Br₉ polycrystalline material is obtained by differential thermal analysis as 464.5 °C, and the position where the freezing point temperature of the Rb₃Sb₂Br₉ polycrystalline material is located is obtained according to the temperature-position relationship curve in step (1). -5 Pa and seal it, and then place it in the quartz furnace tube of a three-zone Bridgman furnace.

[0051] (4) Turn on the heating device to heat the high-temperature zone, middle-temperature zone, and low-temperature zone of the three-zone Bridgman furnace. The temperature of each zone is 650 °C in the high-temperature zone, 500 °C in the middle-temperature zone, and 200 °C in the low-temperature zone. After the temperature is stable, move the quartz tube containing the Rb₃Sb₂Br₉ polycrystalline material up to the high-temperature zone so that the quartz tube is located in the high-temperature zone. After the Rb₃Sb₂Br₉ polycrystalline material is fully melted, lower the quartz tube containing the Rb₃Sb₂Br₉ polycrystalline material at a speed of 8 mm / h. When it drops to the position where the freezing point temperature of the Rb₃Sb₂Br₉ polycrystalline material is located, adjust the dropping speed to 0.2 mm / h. As the quartz tube drops, single crystal growth occurs. After the growth is completed, cool the furnace temperature to room temperature over 48 h to obtain an Rb₃Sb₂Br₉ single crystal.

[0052] Example 4 A method for growing an Rb₃Sb₂Br₉ single crystal, comprising the following steps: (1) Turn on the heating device to heat the high-temperature zone, middle-temperature zone, and low-temperature zone of the three-zone Bridgman furnace. The temperature of each zone is 700 °C in the high-temperature zone, 550 °C in the middle-temperature zone, and 300 °C in the low-temperature zone. Use the temperature sensors installed in the quartz furnace tube to measure the temperatures at different positions from top to bottom of the three-zone Bridgman furnace to obtain the temperature-position relationship curve.

[0053] (2) Weigh RbBr and SbBr₃ raw materials in a molar ratio of 3:2, place them in a mortar, mix evenly and grind thoroughly, transfer to a quartz tube, evacuate to 10 -5 Pa and seal it, then sinter it. The sintering process is as follows: Heat it to 650 °C over 16 h, hold for 36 h, and cool to room temperature over 24 h to obtain a pure-phase Rb₃Sb₂Br₉ polycrystalline material. The freezing point temperature of this Rb₃Sb₂Br₉ polycrystalline material is obtained by differential thermal analysis as 464 °C, and the position where the freezing point temperature of the Rb₃Sb₂Br₉ polycrystalline material is located is obtained according to the temperature-position relationship curve in step (1).

[0054] (3) Load the pure-phase Rb3Sb2Br9 polycrystalline material into a quartz tube, evacuate it to 10 -5 Pa and seal it, then load it into the quartz furnace tube of a three-zone Bridgman furnace.

[0055] (4) Turn on the heating device to heat the high-temperature zone, medium-temperature zone, and low-temperature zone of the three-zone Bridgman furnace. The temperatures of each zone are 700 °C for the high-temperature zone, 550 °C for the medium-temperature zone, and 300 °C for the low-temperature zone. After the temperature stabilizes, move the quartz tube containing the Rb3Sb2Br9 polycrystalline material upward to the high-temperature zone so that the quartz tube is located in the high-temperature zone. After the Rb3Sb2Br9 polycrystalline material is fully melted, lower the quartz tube containing the Rb3Sb2Br9 polycrystalline material at a speed of 8 mm / h. When it drops to the position where the solidification point temperature of the Rb3Sb2Br9 polycrystalline material is located, adjust the dropping speed to 0.3 mm / h. As the quartz tube drops, single crystals grow. After the growth is completed, cool the furnace temperature to room temperature over 60 h to obtain Rb3Sb2Br9 single crystals.

[0056] Example 5 A method for growing Rb3Sb2Br9 single crystals, comprising the following steps: (1) Turn on the heating device to heat the high-temperature zone, medium-temperature zone, and low-temperature zone of the three-zone Bridgman furnace. The temperatures of each zone are 750 °C for the high-temperature zone, 600 °C for the medium-temperature zone, and 450 °C for the low-temperature zone. Use the temperature sensors installed in the quartz furnace tube to measure the temperatures at different positions from top to bottom of the three-zone Bridgman furnace, and obtain the relationship curve between temperature and position.

[0057] (2) Weigh the RbBr and SbBr3 raw materials according to a molar ratio of 3:2, place them in a mortar, mix them evenly and grind them thoroughly, then transfer them to a quartz tube, evacuate it to 10 -5 Pa and seal it, and carry out sintering. The sintering process is as follows: heat it to 650 °C in 15 h, keep it at this temperature for 25 h, and then cool it to room temperature in 22 h to obtain the pure-phase Rb3Sb2Br9 polycrystalline material. Use differential thermal analysis to measure that the solidification point temperature of this Rb3Sb2Br9 polycrystalline material is 463.5 °C, and obtain the position where the solidification point temperature of the Rb3Sb2Br9 polycrystalline material is located according to the relationship curve between temperature and position in step (1).

[0058] (3) Load the pure-phase Rb3Sb2Br9 polycrystalline material into a quartz tube, evacuate it to 10 -5 Pa and seal it, then load it into the quartz furnace tube of a three-zone Bridgman furnace.

[0059] (4) Turn on the heating device to heat the high-temperature zone, medium-temperature zone, and low-temperature zone of the three-zone Bridgman furnace. The temperature of each zone is 750 °C for the high-temperature zone, 600 °C for the medium-temperature zone, and 450 °C for the low-temperature zone. After the temperature stabilizes, raise and move the quartz tube containing the Rb3Sb2Br9 polycrystalline material to the high-temperature zone so that the quartz tube is located in the high-temperature zone. After the Rb3Sb2Br9 polycrystalline material is fully melted, lower the quartz tube containing the Rb3Sb2Br9 polycrystalline material at a speed of 5 mm / h. When it descends to the position where the solidification point temperature of the Rb3Sb2Br9 polycrystalline material is located, adjust the descent speed to 0.4 mm / h. As the quartz tube descends, single crystal growth occurs. After the growth is completed, lower the furnace temperature to room temperature over 80 h to obtain the Rb3Sb2Br9 single crystal.

[0060] Example 6 A method for growing Rb3Sb2Br9 single crystal, comprising the following steps: (1) Turn on the heating device to heat the high-temperature zone, medium-temperature zone, and low-temperature zone of the three-zone Bridgman furnace. The temperature of each zone is 730 °C for the high-temperature zone, 570 °C for the medium-temperature zone, and 400 °C for the low-temperature zone. Use the temperature sensors provided inside the quartz furnace tube to measure the temperatures at different positions from top to bottom of the three-zone Bridgman furnace, and obtain the relationship curve between temperature and position.

[0061] (2) Weigh RbBr and SbBr3 raw materials in a molar ratio of 3:2, place them in a mortar, mix evenly and grind thoroughly, transfer them to a quartz tube, evacuate to 10 -5 Pa and seal it, and carry out sintering. The sintering process is as follows: heat up to 630 °C in 12 h, keep the temperature for 28 h, and cool down to room temperature in 18 h to obtain a pure-phase Rb3Sb2Br9 polycrystalline material. Use differential thermal analysis to measure that the solidification point temperature of this Rb3Sb2Br9 polycrystalline material is 465 °C, and obtain the position where the solidification point temperature of the Rb3Sb2Br9 polycrystalline material is located according to the temperature-position relationship curve in step (1).

[0062] (3) Take the pure-phase Rb3Sb2Br9 polycrystalline material, put it into a quartz tube, evacuate to 10 -5 Pa and seal it, and then put it into the quartz furnace tube of the three-zone Bridgman furnace.

[0063] (4) Turn on the heating device to heat the high-temperature zone, medium-temperature zone, and low-temperature zone of the three-temperature-zone Bridgman furnace. The temperature of each zone is 730 °C for the high-temperature zone, 570 °C for the medium-temperature zone, and 400 °C for the low-temperature zone. After the temperature is stabilized, move the quartz tube containing the Rb3Sb2Br9 polycrystalline material upward to the high-temperature zone so that the quartz tube is located in the high-temperature zone. After the Rb3Sb2Br9 polycrystalline material is fully melted, lower the quartz tube containing the Rb3Sb2Br9 polycrystalline material at a speed of 6 mm / h. When it descends to the position where the solidification point temperature of the Rb3Sb2Br9 polycrystalline material is located, adjust the descent speed to 0.5 mm / h. As the quartz tube descends, single crystal growth occurs. After the growth is completed, lower the furnace temperature to room temperature over 100 h to obtain the Rb3Sb2Br9 single crystal.

[0064] The X-ray powder diffraction pattern of the Rb3Sb2Br9 crystal obtained in Example 1 is as Figure 2 shown, and the appearance photo of the crystal is as Figure 3 shown in (a) therein. Figure 2 The powder diffraction pattern shows that the obtained product phase is Rb3Sb2Br9 and the ingot is transparent. Figure 3 As can be seen from (a) therein, the whole crystal is relatively transparent, the diameter of the ingot reaches 12 mm, and a large-size crystal is successfully obtained. Figure 3 The wafer located at the lower part of (a) therein has good light transmittance, and the grid paper stripes at the bottom can be seen through the wafer. The crystal grown in Comparative Example 1 is as Figure 4 shown, and it can be seen that there are obvious cracks in the upper part of the formed crystal, and the quality of the grown single crystal is poor. The crystal grown in Comparative Example 2 is as Figure 5 shown, and it can be seen that the tip of the formed ingot grows relatively transparently, and the overall quality of the single crystal grown at a speed of 1.2 mm / h in Comparative Example 1 is slightly better, but it is still not transparent enough. By comparing Example 1 and Comparative Examples 1 and 2, it can be seen that when the quartz tube containing the Rb3Sb2Br9 polycrystalline material moves at a lower speed at the solidification point temperature of the Rb3Sb2Br9 polycrystalline material, it is beneficial to single crystal growth, the grown single crystal has no cracks and high transparency, and when it moves at a higher speed, the quality of the grown single crystal will decrease.

[0065] Combined with the layered cleavage property of Rb3Sb2Br9, a razor blade was used to split the crystal prepared in Example 1 along the cleavage direction. The crystal could spontaneously form millimeter-scale monoclinic wafers. Then, sandpapers with 1200, 2000, 5000, 7000, 10000, and 20000 meshes were used in sequence, with WD-40 as the lubricant, to polish the surface of the wafer edges. After polishing, an Al2O3 nano-suspension was used in combination with WD-40 to further polish the wafer edges. After polishing, the wafers were placed in a toluene solution, and the residual polishing liquid on the wafer surface was removed by ultrasonic cleaning. A metal Au electrode was deposited by magnetron sputtering technology to fabricate a three-layer structure of metal electrode - perovskite single crystal - metal electrode, and an X-ray detector was obtained, as Figure 3 shown in (b) of

[0066] As Figure 6 shown, the resistivity of the prepared X-ray detector was 1.64×10 10 . As Figure 7 shown in (a) of Figure 7 , in the current-time graph under the irradiation of X-rays excited by a 10 kV tube voltage with a bias voltage of 16 V, it can be seen that the X-ray detector has a good switching effect.

[0067] The specific embodiments described above are only detailed descriptions for explaining the present invention and are not intended to limit the present invention. Any modifications and equivalent replacements made within the principles involved in the present invention should be included within the protection scope of the present invention.

Claims

1. A method for growing Rb3Sb2Br9 single crystals, characterized in that, Including: S1. React rubidium bromide and antimony bromide to prepare Rb3Sb2Br9 polycrystalline material. S2. Load the Rb3Sb2Br9 polycrystalline material into a container, evacuate and seal the container, and then load it into a crystal growth furnace. The crystal growth furnace is successively a high-temperature zone, a medium-temperature zone, and a low-temperature zone from one end to the other end. S3. Heat and raise the temperature of the high-temperature zone, medium-temperature zone, and low-temperature zone of the crystal growth furnace to the preset temperature of each zone, move the container containing the Rb3Sb2Br9 polycrystalline material to the high-temperature zone to melt the Rb3Sb2Br9 polycrystalline material in the container, and then gradually move the container containing the Rb3Sb2Br9 polycrystalline material to the medium-temperature zone and the low-temperature zone to realize the growth of Rb3Sb2Br9 single crystal. Among them, the preset temperature of the high-temperature zone is 600 - 750 °C, the preset temperature of the medium-temperature zone is 450 - 600 °C, and the preset temperature of the low-temperature zone is 200 - 450 °C. S4. After the growth is completed, cool down to room temperature to obtain Rb3Sb2Br9 single crystal.

2. The growth method of Rb3Sb2Br9 single crystal according to claim 1, characterized in that, Specifically, S1 is: Mix and grind rubidium bromide and antimony bromide, place the obtained mixture in a container, evacuate and seal the container, and then sinter to obtain Rb3Sb2Br9 polycrystalline material.

3. The growth method of the Rb3Sb2Br9 single crystal according to claim 2, characterized in that, The sintering process is: Raise the temperature to 500 - 650 °C, keep the temperature for 24 - 36 h, and then cool down to room temperature.

4. The growth method of the Rb3Sb2Br9 single crystal according to claim 3, characterized in that, During the sintering process, the heating time is 12 - 16 h, and the cooling time is 16 - 24 h.

5. The growth method of the Rb3Sb2Br9 single crystal according to claim 1, characterized in that, Previously test the temperatures at different positions from one end to the other end of the crystal growth furnace at the preset temperatures of each zone to obtain the relationship curve between temperature and position; Test the freezing point temperature of the Rb3Sb2Br9 polycrystalline material through differential thermal analysis, and obtain the position where the freezing point temperature is located according to the relationship curve between temperature and position. In S3, when the container containing the Rb3Sb2Br9 polycrystalline material gradually moves from the high-temperature zone to the medium-temperature zone and the low-temperature zone, the moving speed in the high-temperature zone is 5 - 8 mm / h, and when moving to the position where the freezing point temperature is located, the moving speed is adjusted to 0.2 - 0.5 mm / h.

6. The growth method of Rb3Sb2Br9 single crystal according to claim 1, characterized in that, In S4, the cooling time is 48 - 120 h.

7. Rb3Sb2Br9 single crystal obtained by the growth method described in any one of claims 1 - 6.

8. An X-ray detector, characterized in that, Including the Rb3Sb2Br9 single crystal described in claim 7.

9. The method for preparing the X-ray detector according to claim 8, characterized in that, Including: (1) Grind, polish, clean, and dry the Rb3Sb2Br9 single crystal in sequence. (2) Deposit metal electrodes on the Rb3Sb2Br9 single crystal obtained in step (1) to fabricate a three-layer structure of metal electrode - perovskite single crystal - metal electrode.

10. Application of the Rb3Sb2Br9 single crystal described in claim 7 or the X-ray detector described in claim 8 in X-ray detection.

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