Preparation method and application of Rb2CuBr3 single crystal and wafer

Abstract

The invention belongs to the field of inorganic crystal materials, and particularly relates to a preparation method and application of an Rb2CuBr3 single crystal and a wafer. According to the preparation method of the Rb2CuBr3 single crystal, the raw material ratio and the solvent dosage are optimized, and a cooling method induced by a same-component seed crystal is adopted for growth, so that ions seamlessly and epitaxially grow along a seed crystal structure, polycrystals or defects are avoided, solute is more easily and directionally deposited on the surface of the seed crystal, and the crystal quality is improved. The Rb2CuBr3 wafer with the inch-level size is prepared by further combining with a hot pressing process, the nano / micron-level limitation of a traditional process is broken through, size rising from a rod-shaped single crystal to a large-area wafer is achieved, and the crystal growth efficiency and size uniformity are remarkably improved. The photoelectric property of the Rb2CuBr3 wafer is remarkably improved, the luminous quantum yield reaches 96.84%, the exciton lifetime is 69.01 microseconds, the ultraviolet responsivity reaches 177.4 mA / W, the specific detection rate is improved to 1.9 * 10 < 13 > Jones, the large-area application requirement of a high-sensitivity detection device is met, and the application of the Rb2CuBr3 wafer in the fields of ultraviolet photoelectric detection and X-ray detection is expanded.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of inorganic crystal materials, and particularly relates to a preparation method and application of Rb2CuBr3 single crystal and wafer. BACKGROUND

[0002] Ultraviolet photodetection technology is of great significance in military and civilian fields. In military field, it can be used for missile early warning, target tracking, etc. In civilian field, it covers flame detection, space communication, biomedical analysis, marine oil pollution monitoring, etc. For example, specific wavelength ultraviolet rays of early stage flame radiation can be quickly responded by the technology to realize early warning. However, with the development of science and technology, higher requirements are put forward for the sensitivity, response speed and response spectral range of the technology. However, due to the limited band gap adjustment range (410-700 nm), lead toxicity and instability of organic ammonium salt, the development of some materials (such as organic-inorganic lead halide perovskite) in this field is restricted.

[0003] X-ray detection technology is crucial in medical imaging, security and safety inspection, industrial non-destructive testing and deep space exploration. As the core of X-ray detector, the scintillator can convert high-energy rays into low-energy photons, which are collected by a sensor array such as a photomultiplier tube, a photon counter, a charge-coupled device, etc. and then imaged. The performance of the scintillator is a key factor to realize high-quality X-ray detection and imaging. The performance of the scintillator material directly affects the detection sensitivity and imaging quality. Lead halide perovskite has been concerned due to its high luminous efficiency, but lead toxicity and low light yield limit its application. For example, Chinese invention patent CN108691012A discloses a kind of perovskite CsPbBr3 with high photoelectric response efficiency and room temperature stability. x I x The crystal and its preparation method and application are grown by reverse temperature evaporation crystallization method, and a perovskite crystal material with high crystallization quality, uniform Br - and I - distribution is prepared. However, the crystal size obtained by the above method is only millimeter level (the maximum size is 5.6x4.9x1.4mm 3 ), and the raw material used contains toxic lead element, which has certain limitations.

[0004] In recent years, copper halide (such as Rb2CuBr3) as a lead-free alternative material, due to high photoluminescence quantum yield, large stokes shift and excellent stability, has become a research hotspot of new X-ray scintillator. The mainstream preparation methods of copper halide at present include solvent evaporation method, anti-solvent method, cooling method, hot pressing method, anti-solvent vapor assisted crystallization method, thermal injection method, ball milling method and so on. These methods have their own characteristics, but all have obvious limitations: the solvent evaporation method has slow crystallization, low efficiency, small and uneven crystal size; the anti-solvent method needs to use toxic anti-solvent, has poor controllability of crystallization, is difficult to obtain high-quality single crystal, and has high solvent recovery cost; the anti-solvent vapor assisted crystallization method has difficult to control the vapor diffusion rate, poor crystal uniformity, is only suitable for nanoscale materials, and has high equipment cost; the thermal injection method depends on toxic organic ligand, has violent reaction, can only prepare nanoscale materials, and the organic residue affects the performance; the ball milling method easily introduces impurities, has many crystal defects, poor photoelectric performance, low photoluminescence quantum yield, and can only obtain polycrystalline powder, cannot prepare single crystal, and the size and morphology are difficult to control. For example, Chinese invention patent CN113550004A introduces a vapor pressure assisted preparation method of copper halide material and its product and application, mixes cesium halide, cuprous halide and hydrogen halide acid, and then adopts vapor pressure assisted cooling crystallization to react, however, the prepared copper halide product has small size, low photoluminescence quantum yield of only 36%, short exciton lifetime, and the optical performance is difficult to meet the current application demand. Therefore, developing a copper halide preparation method which can realize large crystal size, high crystallization quality, few defects, no toxic organic ligand, and can meet the X-ray detection and ultraviolet photoelectric detection is the current research focus. SUMMARY

[0005] Therefore, the purpose of the present application is to provide a preparation method of Rb2CuBr3 material. The preparation method of Rb2CuBr3 single crystal grows by optimizing the raw material ratio, solvent amount, adopting the same component seed crystal induced cooling method, making ions grow seamlessly along the seed crystal structure, avoiding the generation of polycrystal or defect, making solute more easily directional deposit on the seed crystal surface, and improving the crystallization quality. Further combined with the hot pressing process, an inch level size Rb2CuBr3 wafer is prepared, breaking through the nanometer / micron level limitation of traditional process, realizing the size leap from rod-like single crystal to large area wafer, and significantly improving the crystal growth efficiency and size uniformity. The photoelectric performance of Rb2CuBr3 wafer is significantly improved, meeting the large area application demand of high sensitivity detector, and expanding its application in the fields of ultraviolet photoelectric detection and X-ray detection.

[0006] In order to achieve the above purpose, the present application provides the following technical scheme:

[0007] A preparation method of Rb2CuBr3 single crystal, comprising the following steps:

[0008] S1: Preparation of precursor solution: rubidium bromide and cuprous bromide are used as raw materials, dissolved in a hydrogen bromide solution and deionized water with a volume ratio of 2:1, and a hypophosphorous acid solution is added to obtain a mixture A; the mixture A is stirred at 100℃ until completely dissolved to form a transparent precursor solution, and then impurities are removed by rapid filtration through a 0.45μm PTFE filter to obtain a filtered precursor solution B; the molar volume ratio of the rubidium bromide, cuprous bromide, hydrogen bromide solution and hypophosphorous acid solution is 2:1:0.5-1:100-150mmol:mmol:mL:μL; the concentration of the hydrogen bromide is 10-50%, and the concentration of the hypophosphorous acid is 50%;

[0009] S2: Seed crystal preparation: part of the precursor solution B obtained in step S1 is taken and cooled from 100℃ to 25±2℃ at a cooling rate of 1-3℃ / h to obtain initial Rb2CuBr3 crystals, and Rb2CuBr3 rod-shaped crystals with a length size greater than 5mm and growing along the

[010] crystal direction are selected as seed crystals, and the seed crystals are then placed in a container;

[0010] S3: Single crystal preparation: another part of the precursor solution B obtained in step S1 is taken and placed in a container heated to 80℃ in advance and containing seed crystals, and the volume ratio of the seed crystals to the precursor solution B is 1:50-1:100, and the temperature is slowly reduced from 80℃ to 25±2℃ at a cooling rate of 1-3℃ / h; the crystal is promoted to grow along one-dimensional direction by seed crystal induction, and finally Rb2CuBr3 single crystals are formed.

[0011] Preferably, in step S1: the molar volume ratio of rubidium bromide, cuprous bromide, hydrogen bromide solution and hypophosphorous acid solution is 2:1:0.5-0.7:130-150uL; the concentration of the hydrogen bromide is 30-50%.

[0012] Preferably, in step S2: the cooling rate is 1-2℃ / h.

[0013] Preferably, in step S3: the cooling rate is 1-2℃ / h; the volume ratio of the seed crystals to the precursor solution B is 1:70-1:90.

[0014] An Rb2CuBr3 wafer and a preparation method thereof, comprising the following steps:

[0015] After the Rb2CuBr3 single crystal with a mass of 500-900mg is ground into powder, the powder is placed in a hot press; the hot pressing is performed at a temperature of 90-150℃ and a pressure of 1-300MPa for 4h; after the hot pressing is completed, an Rb2CuBr3 wafer is finally obtained.

[0016] Preferably, the hot pressing temperature is 100-120℃; the hot pressing pressure is 150-250MPa.

[0017] The beneficial effects of the present application are:

[0018] 1) High crystallization performance advantage: Rb2CuBr3 single crystal is grown by the same composition seed crystal induction cooling method, so that ions grow seamlessly along the seed crystal structure, avoiding the generation of polycrystals or defects, and solutes are more easily deposited on the seed crystal surface, improving the crystallization quality.

[0019] 2) Significant size advantage: By optimizing the raw material ratio, solvent dosage, combining seed crystal guided cooling growth and hot pressing method preparation process, inch-level large-size Rb2CuBr3 is prepared, effectively improving the crystal growth efficiency and size uniformity.

[0020] 3) Optical performance is improved: the luminescence quantum yield reaches 96.84%, and the exciton lifetime is 69.01us, significantly improving the carrier transport efficiency.

[0021] 4) Breakthrough in ultraviolet detection performance: the ultraviolet response reaches 177.4mA / W; the specific detectivity is improved to 1.9x10 13 Jones, close to the theoretical numerical limit, the performance strength significantly surpasses the samples prepared by saturated crystallization method and vacuum thermal evaporation method.

[0022] 5) Good application adaptability: solve the contradiction between large-size crystal and high crystallization quality, have high photoelectric response rate, meet the application requirements of large-area detector devices of ultraviolet photodetector and X-ray scintillator. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to make the purpose, technical scheme and advantages of the present application clearer, the preferred detailed description of the present application will be made below in combination with the drawings, in which:

[0024] Figure 1 (a) is a preparation flowchart of Rb2CuBr3 single crystal; (b) is a preparation flowchart of Rb2CuBr3 wafer.

[0025] Figure 2 (a) is a morphology diagram of Rb2CuBr3 seed crystal; (b) is a morphology diagram of Rb2CuBr3 single crystal obtained after seed crystal induction growth.

[0026] Figure 3 It is a photo of Rb2CuBr3 single crystal under sunlight and ultraviolet light.

[0027] Figure 4 It is an inch-level Rb2CuBr3 wafer morphology diagram.

[0028] Figure 5 It is a scanning electron microscope diagram of Rb2CuBr3 wafer.

[0029] Figure 6Photoluminescence spectra and photoluminescence excitation spectra of Rb2CuBr3 single crystal and wafer.

[0030] Figure 7 Transient fluorescence lifetime spectra of Rb2CuBr3 wafer.

[0031] Figure 8 Ultraviolet light absorption spectra of Rb2CuBr3 wafer.

[0032] Figure 9 Test results of Rb2CuBr3 wafer applied to ultraviolet photoelectric response device: (a) is the switch ratio and response time diagram of the ultraviolet photoelectric response test device; (b) is the photocurrent response diagram under 255 nm ultraviolet light; (c) is the device responsivity and specific detectivity diagram.

[0033] Figure 10 Response current change diagram of the device under different X-ray doses. DETAILED DESCRIPTION

[0034] Other advantages and benefits of the present application will become apparent to those skilled in the art from the following detailed description of specific embodiments of the present application, taken in conjunction with the accompanying drawings. The present application can be implemented or applied in other different specific embodiments, and the details in the specification can be modified or changed based on different views and applications without departing from the spirit of the present application.

[0035] Example 1

[0036] The preparation method of Rb2CuBr3 single crystal and wafer is shown in the preparation flow as Figure 1 shown, and the specific steps are as follows:

[0037] 1) Preparation of precursor solution: 3.2 mmol of rubidium bromide and 1.6 mmol of cuprous bromide were selected as raw materials, dissolved in a mixed solvent of 0.5 ml of hydrobromic acid solution (48% concentration) and 0.25 ml of deionized water, and then 100 μl of hypophosphorous acid solution (50% concentration) was added to obtain mixture A. Mixture A was stirred at 100°C until completely dissolved to form a transparent precursor solution, which was then quickly filtered through a 0.45 μm PTFE filter to remove impurities to obtain filtered precursor solution B.

[0038] 2) Seed crystal preparation: part of the precursor solution B was taken, and the temperature was slowly reduced from 100°C to 25±2°C at a rate of 1°C / h to obtain initial Rb2CuBr3 crystals. The crystals with a size greater than 5 mm and grown along the

[010] crystal direction were selected as seed crystals. The morphology of the seed crystal is shown in Figure 2 (a).

[0039] 3) Single crystal preparation: Take another part of precursor solution B and inject it into a container containing a seed crystal (the container needs to be preheated to 80°C). The volume ratio of seed crystal to precursor solution B is 1:80. Slowly cool from 80°C to 25±2°C at a rate of 1°C / h to promote the directional growth of the crystal in one dimension, forming a regular rod-shaped Rb2CuBr3 single crystal with a size of 1.5x0.5 cm, as shown in Figure 2 (b). Figure 3 For the luminescence of Rb2CuBr3 single crystals, under the irradiation of 305 nm ultraviolet light, the photoluminescence of the crystal presents purple light, and the corresponding emission wavelength is 388 nm. Rb2CuBr3 single crystals are grown by the same composition seed crystal induction cooling method. The core principle is to realize the increase of crystal size through structure matching and kinetic regulation: (1) Structure template effect: The lattice constant and crystal direction of the same composition seed crystal and the target crystal are completely consistent, which provides precise atomic level adsorption sites for Rb + , Cu + , Br - ions in the solution, so that the ions grow seamlessly along the seed crystal structure, avoiding the formation of polycrystals or defects. (2) Inhibition of random nucleation: The seed crystal reduces the nucleation energy barrier, making it easier for solutes in the solution to deposit on the seed crystal surface rather than randomly form new crystal nuclei, reducing grain competition and concentrating solute supply for seed crystal growth. (3) Cooling rate control synergy: Slow cooling maintains low supersaturation of the solution, combined with anisotropic growth guided by the seed crystal (such as preferential extension along the one-dimensional chain direction), ultimately realizing the directional growth of large-size single crystals.

[0040] 4) Wafer preparation: Grind the Rb2CuBr3 single crystal with a mass of 773 mg into powder and place it in a hot press; heat press at a temperature of 120°C and a pressure of 100 MPa for 4h; after heat pressing, the final Rb2CuBr3 wafer is obtained. After heat pressing, a Rb2CuBr3 wafer with a diameter of 1 inch and a thickness of 0.6 mm is obtained. Figure 4 is the morphology of the Rb2CuBr3 wafer prepared in this embodiment.

[0041] Figure 5 is the scanning electron microscope image of the Rb2CuBr3 wafer prepared in this embodiment. It can be seen that the rod-shaped single crystal has high crystalline quality after heat pressing, realizing the size jump from rod-shaped single crystal to large-area wafer, adapting to the preparation needs of large-area detection devices.

[0042] Figure 6The photoluminescence excitation spectrum and the photoluminescence spectrum of the Rb2CuBr3 single crystal and wafer prepared in the embodiment can show that the absorption peak position of the photoluminescence excitation spectrum of the Rb2CuBr3 single crystal is 312 nm, and the absorption peak position of the photoluminescence spectrum is 386 nm. After the hot-pressing process, the high temperature and high pressure can introduce stress in the wafer, and the stress can cause the lattice of the crystal to be distorted, and then the energy band structure of the crystal is changed. The change of the energy band structure can affect the transition energy of the electron, so that the energy range of the light absorption is changed, and finally the absorption peak position of the Rb2CuBr3 wafer is moved, the absorption peak position of the Rb2CuBr3 wafer in the photoluminescence excitation spectrum is moved to 302 nm, and the absorption peak position of the photoluminescence spectrum is 388 nm.

[0043] Figure 7 The transient fluorescence spectrum and the luminescence quantum yield diagram of the Rb2CuBr3 wafer prepared in the embodiment can show that the Rb2CuBr3 wafer has a high luminescence quantum yield of 96.84% and a long exciton lifetime of 69.01 μs, which is conducive to the efficient transmission of carriers.

[0044] Figure 8 The ultraviolet absorption spectrum diagram of the Rb2CuBr3 wafer can show that there is an absorption peak at 260-315 nm, which is coordinated with the photoluminescence excitation spectrum and the photoluminescence spectrum, and presents a process of "absorption-excitation-emission", indicating that the Rb2CuBr3 material has an optical response to ultraviolet light.

[0045] Figure 9 The test result diagram of the Rb2CuBr3 wafer applied to the ultraviolet photoelectric response device can show that the response time of the Rb2CuBr3 wafer is 197.9 / 153.2 ms, and has a high on-off ratio of 569; (b) is the photocurrent response diagram under 255 nm ultraviolet light, and the bias voltage is 5 V. The Rb2CuBr3 wafer is used as the core element of the ultraviolet photodetector, and the photocurrent response of the Rb2CuBr3 wafer under different ultraviolet light intensities is tested. The results show that the detector has a good linear response range and high sensitivity, and can be applied to the field of ultraviolet light detection; (c) is the device responsivity and specific detectivity diagram, which can show that the photocurrent responsivity is 177.4 mA / W, and the specific detectivity is 1.9×10 13 Jones, and the specific detectivity has reached close to the theoretical detection limit.

[0046] Figure 10The X-ray I-T test results show that, for the response current changes of the device under different X-ray doses, as the X-ray dose decreases, the corresponding response current of the device decreases, showing good dose dependence, indicating that the Rb2CuBr3 wafer can realize accurate response to different dose rays in X-ray detection, and has application potential as a high-sensitivity X-ray detection material.

[0047] Example 2

[0048] The preparation method of the Rb2CuBr3 single crystal and wafer is as follows:

[0049] 1) Preparation of precursor solution: 2.4 mmol of rubidium bromide and 1.2 mmol of cuprous bromide were selected as raw materials, dissolved in a mixed solvent of 0.5 ml of hydrobromic acid solution (30% concentration) and 0.25 ml of deionized water, and then 100 μl of hypophosphorous acid solution (50% concentration) was added to obtain a mixture A. The mixture A was stirred at 100℃ until completely dissolved to form a transparent precursor solution, and then filtered through a 0.45 μm PTFE filter to remove impurities to obtain a filtered precursor solution B.

[0050] 2) Seed crystal preparation: part of the precursor solution B was taken, and the temperature was slowly reduced from 100℃ to 25±2℃ at a rate of 3℃ / h to obtain the initial Rb2CuBr3 crystal. The crystal with a size greater than 5 mm and grown along the

[010] crystal direction was selected as the seed crystal.

[0051] 3) Single crystal preparation: another part of the precursor solution B was injected into a container containing the seed crystal (the container was preheated to 80℃), and the volume ratio of the seed crystal to the precursor solution B was 1:50. The temperature was slowly reduced from 80℃ to 25±2℃ at a rate of 3℃ / h to promote the directional growth of the crystal along the one-dimensional direction, and a centimeter-sized Rb2CuBr3 regular rod-shaped single crystal was formed. The size of the single crystal was 1.2×0.4 cm.

[0052] 4) Wafer preparation: the Rb2CuBr3 single crystal with a mass of 580 mg was ground into powder and then placed in a hot press; the temperature was 150℃ and the pressure was 300 MPa, and the hot pressing was carried out for 4 h; after the hot pressing was completed, the Rb2CuBr3 wafer was finally obtained. The Rb2CuBr3 wafer with a diameter of 1 inch and a thickness of 0.4 mm was finally obtained.

[0053] Example 3

[0054] The preparation method of the Rb2CuBr3 single crystal and wafer is as follows:

[0055] 1) Preparation of precursor solution: 2.8 mmol of rubidium bromide and 1.4 mmol of cuprous bromide were selected as raw materials, dissolved in a mixed solvent of 0.5 ml of hydrobromic acid solution (10% concentration) and 0.25 ml of deionized water, and then 100 μl of hypophosphorous acid solution (50% concentration) was added to obtain mixture A. Mixture A was stirred at 100°C until completely dissolved to form a transparent precursor solution, which was then quickly filtered through a 0.45 μm PTFE filter to remove impurities to obtain filtered precursor solution B.

[0056] 2) Seed crystal preparation: A portion of the precursor solution B was taken and slowly cooled from 100°C to 25±2°C at a cooling rate of 2°C / h to obtain initial Rb2CuBr3crystals. Crystals with a size greater than 5 mm and grown along the

[010] crystal direction were selected as seed crystals.

[0057] 3) Single crystal preparation: Another portion of the precursor solution B was injected into a container containing the seed crystal (the container was preheated to 80°C). The volume ratio of the seed crystal to the precursor solution B was 1:100. The temperature was slowly reduced from 80°C to 25±2°C at a rate of 2°C / h to promote the directional growth of the crystal in one dimension, forming a centimeter-sized regular rod-shaped Rb2CuBr3single crystal with a size of 1.4 x 0.45 cm.

[0058] 4) Wafer preparation: The obtained Rb2CuBr3single crystal was ground into powder and placed in a hot press for hot pressing treatment. The hot pressing temperature was 90°C, the pressure was 200 MPa, and the hot pressing time was 4 h. Finally, a Rb2CuBr3wafer with a diameter of 1 inch and a thickness of 0.5 mm was obtained.

[0059] Example 4

[0060] The preparation method of the Rb2CuBr3single crystal and wafer is as follows:

[0061] 1) Preparation of precursor solution: 3.6 mmol of rubidium bromide and 1.8 mmol of cuprous bromide were selected as raw materials, dissolved in a mixed solvent of 0.5 ml of hydrobromic acid solution (50% concentration) and 0.25 ml of deionized water, and then 100 μl of hypophosphorous acid solution (50% concentration) was added to obtain mixture A. Mixture A was stirred at 100°C until completely dissolved to form a transparent precursor solution, which was then quickly filtered through a 0.45 μm PTFE filter to remove impurities to obtain filtered precursor solution B.

[0062] 2) Seed crystal preparation: A portion of the precursor solution B was taken and slowly cooled from 100°C to 25±2°C at a cooling rate of 1°C / h to obtain initial Rb2CuBr3crystals. Crystals with a size greater than 5 mm and grown along the

[010] crystal direction were selected as seed crystals.

[0063] 3) Single crystal preparation: another part of the precursor solution B was injected into a container containing a seed crystal (the container was preheated to 80°C), the volume ratio of the seed crystal to the precursor solution B was 1:90, and the temperature was slowly reduced from 80°C to 25±2°C at a rate of 1°C / h to promote the directional growth of the crystal in one dimension, forming a regular rod-shaped single crystal of Rb2CuBr3 with a size of 1.6x0.55 cm.

[0064] 4) Wafer preparation: after the obtained Rb2CuBr3 single crystal was ground into powder, the powder was placed in a hot press for hot pressing treatment, the hot pressing temperature was 90°C, the pressure was 1 MPa, and the hot pressing time was 4 h. Finally, a Rb2CuBr3 wafer with a diameter of 1 inch and a thickness of 0.9 mm was obtained.

[0065] Finally, it should be pointed out that the above examples are only used to illustrate the technical solutions of the present application and are not limiting. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the spirit and scope of the present application, and all should be covered in the scope of the claims of the present application.

Claims

1. A method for preparing Rb₂CuBr₃ single crystal, characterized in that, Includes the following steps: S1: Preparation of precursor solution: Rubidium bromide and cuprous bromide were used as raw materials, dissolved in hydrobromic acid solution and deionized water at a volume ratio of 2:1, and hypophosphite solution was added to obtain mixture A; mixture A was stirred at 100°C until completely dissolved to form a transparent precursor solution, which was then rapidly filtered through a 0.45μm PTFE filter to remove impurities, obtaining filtered precursor solution B; the molar volume ratio of rubidium bromide, cuprous bromide, hydrobromic acid solution and hypophosphite solution was 2:1:0.5~1:100~150mmol:mmol:mL:μL; the concentration of hydrobromic acid was 10~50%, and the concentration of hypophosphite was 50%; S2: Seed crystal preparation: Take part of the precursor solution B obtained in step S1 and cool it from 100℃ to 25±2℃ at a cooling rate of 1~3℃ / h to obtain initial Rb2CuBr3 crystals. Select Rb2CuBr3 rod-shaped crystals that grow along the [010] crystal direction and have a length dimension greater than 5mm as seed crystals, and then put the seed crystals into a container. S3: Single crystal preparation: Take another part of the precursor solution B obtained in step S1 and put it into a container containing a seed crystal that has been preheated to 80°C. The volume ratio of the seed crystal to the precursor solution B is 1:50 to 1:

100. The temperature is lowered from 80°C to 25±2°C at a cooling rate of 1 to 3°C / h. This promotes the directional growth of the crystal along the one-dimensional direction induced by the seed crystal, and finally forms a Rb2CuBr3 single crystal.

2. The preparation method according to claim 1, characterized in that, In step S1, the molar volume ratio of rubidium bromide, cuprous bromide, hydrobromic acid solution, and hypophosphoric acid solution is 2:1:0.5-0.7:130-150 μL; the concentration of hydrobromic acid is 30-50%.

3. The preparation method according to claim 1, characterized in that, In step S2, the cooling rate is 1-2℃ / h.

4. The preparation method according to claim 1, characterized in that, In step S3: the cooling rate is 1-2℃ / h; the volume ratio of seed crystal to precursor solution B is 1:70-1:

90.

5. A method for preparing Rb₂CuBr₃ wafers, characterized in that, The Rb2CuBr3 single crystal obtained by any one of the methods described in claims 1 to 4 is prepared by the following steps: 500 to 900 mg of Rb2CuBr3 single crystal is ground into powder and then placed in a hot press; hot pressing is performed at a temperature of 90 to 150°C and a pressure of 1 to 300 MPa for 4 hours; after hot pressing, Rb2CuBr3 wafers are finally obtained.

6. The preparation method according to claim 5, characterized in that, The hot pressing temperature is 100-120℃; the hot pressing pressure is 150-250MPa.

7. The Rb2CuBr3 wafer obtained by the preparation method according to claim 5.

8. Applications of Rb2CuBr3 wafers in ultraviolet photoelectric detection and X-ray detection.

Images