CsPbBr3 single crystal and growth method thereof

Abstract

The invention provides a method for growing a CsPbBr3 single crystal, and belongs to the technical field of perovskite preparation. According to the preparation method, a mixed solvent of dimethyl sulfoxide and N, N-dimethylformamide is used for preparing a precursor solution, and acetonitrile is added to destroy clusters of ions in the precursor solution so as to enable the ions to be uniformly dispersed, so that the concentration of free ions in the precursor solution is improved, the precursor solution is easier to saturate, and the solubility of CsPbBr3 is reduced; after acetonitrile is added, the solubility of CsPbBr3 is in a monotonically decreasing trend at 25-80 DEG C, and the CsPbBr3 has a relatively large solubility change ratio, so that the growth requirement of CsPbBr3 single crystals is met; the initial temperature of crystal growth is controlled through the concentration of the precursor solution, so that the crystal growth temperature is lower than the phase transition temperature; the seed crystal is added when the precursor solution is nearly saturated, so that the seed crystal can be partially dissolved, the interface between the seed crystal and the newly grown crystal is eliminated, and the crystal quality is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of perovskite preparation, and in particular to a CsPbBr3 single crystal and a growth method thereof. Background Art

[0002] Room temperature semiconductor radiation detection devices are detectors made of semiconductor materials, used to detect and measure the radiation of radionuclides, and are used in medical imaging, homeland security, scientific research, and industrial detection. Common room temperature radiation detection materials include CZT, TlBr, and HgI2, but these materials have stability issues or high production costs and cannot be mass-produced and applied.

[0003] Metal halide perovskites have the advantages of high mobility, adjustable band gap, high attenuation coefficient, and low synthesis cost, and have been proven to be applicable to room temperature radiation detectors. + It replaces volatile organic cations and has higher stability than other perovskite single crystals, and has attracted much attention. However, there have always been many problems in the preparation of CsPbBr3 single crystals, making it difficult to obtain high-quality CsPbBr3 single crystals.

[0004] Inversion crystallization is a commonly used method for growing CsPbBr3 single crystals. It uses the abnormal solubility of CsPbBr3 in dimethyl sulfoxide (DMSO) to achieve crystal growth: in dimethyl sulfoxide solvent, the solubility of CsPbBr3 decreases with increasing temperature, and crystal growth is achieved when supersaturation is reached. The usual heating temperature range is 25-120°C, especially at 90-115°C, the solubility of CsPbBr3 changes very steeply, which is the commonly used temperature range for inversion crystallization. However, when crystal growth is carried out within the above temperature range, the crystallized CsPbBr3 single crystal will undergo a phase transition during the cooling process to room temperature, from the orthorhombic phase to the tetragonal phase, which causes the crystal to undergo a phase transition during the cooling process after the growth is completed. The stress generated by the phase transition causes cracks in the crystal, and the crystal quality deteriorates. Summary of the invention

[0005] The object of the present invention is to provide a CsPbBr3 single crystal and a growth method thereof. In the growth method provided by the present invention, the growth temperature of the CsPbBr3 single crystal is lower than the phase transition temperature, thereby avoiding the crystal quality problem caused by the phase transition.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] The present invention provides a method for growing a CsPbBr3 single crystal, comprising the following steps:

[0008] 1) dissolving CsBr and PbBr2 in a mixed solvent of dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF) and acetonitrile (ACN) to obtain a CsPbBr3 precursor solution; the concentration of CsPbBr3 in the CsPbBr3 precursor solution is 0.29-0.40 g / mL; the volume of the acetonitrile is 25-35% of the sum of the volumes of dimethyl sulfoxide and N,N-dimethylformamide;

[0009] 2) The CsPbBr3 precursor solution obtained in step 1) is subjected to a first heating, a seed crystal is added, and then a second heating is performed to a crystallization endpoint temperature to obtain a CsPbBr3 single crystal; the endpoint temperature of the first heating is T0-(1-5)°C; T0 is the temperature at which the CsPbBr3 precursor solution reaches saturation; the crystallization endpoint temperature is not higher than 80°C.

[0010] Preferably, in step 1), the molar ratio of CsBr to PbBr2 is 1:(1.5-2.5).

[0011] Preferably, in step 1), the volume ratio of dimethyl sulfoxide to N,N-dimethylformamide is (3-4):1.

[0012] Preferably, in the step 1), CsBr, PbBr2, dimethyl sulfoxide and N,N-dimethylformamide are first mixed for a coprecipitation reaction to obtain a first solution; and the first solution is secondly mixed with acetonitrile to obtain a CsPbBr3 precursor solution.

[0013] Preferably, after the coprecipitation reaction is completed, filtration is performed to obtain a first solution.

[0014] Preferably, the first heating and the second heating in step 2) are both performed by oil bath heating.

[0015] Preferably, the heating rate of the first heating in step 2) is 5-20° C. / h.

[0016] Preferably, the second heating in step 2) includes a heating saturation stage and a crystal growth stage performed sequentially; the heating rate in the heating saturation stage is 1.5-3°C / day; the heating rate in the crystal growth stage is 1-1.5°C / day.

[0017] Preferably, in step 2), the size of the seed crystal is 0.3 mm×0.3 mm to 0.5 mm×0.5 mm.

[0018] The present invention also provides a CsPbBr3 single crystal obtained by the growth method described in the above technical solution, wherein the crystal orientation family of the CsPbBr3 single crystal is {110}.

[0019] The present invention provides a method for growing a CsPbBr3 single crystal, comprising the following steps: 1) dissolving CsBr and PbBr2 in a mixed solvent of dimethyl sulfoxide, N,N-dimethylformamide and acetonitrile to obtain a CsPbBr3 precursor solution; the concentration of CsPbBr3 in the CsPbBr3 precursor solution is 0.29-0.40 g / mL; the volume of the acetonitrile is 25-35% of the sum of the volumes of dimethyl sulfoxide and N,N-dimethylformamide; 2) performing a first heating on the CsPbBr3 precursor solution obtained in the step 1), adding a seed crystal, and then performing a second heating to a crystallization endpoint temperature to obtain a CsPbBr3 single crystal; the endpoint temperature of the first heating is T0-(1-5)°C; T0 is the temperature at which the CsPbBr3 precursor solution reaches saturation; and the crystallization endpoint temperature is not higher than 80°C. The present invention prepares a precursor solution in a mixed solvent of dimethyl sulfoxide and N,N-dimethylformamide. By adding acetonitrile, the clusters of ions in the precursor solution can be destroyed to make it dispersed evenly, thereby increasing the concentration of free ions in the precursor solution, making the precursor solution easier to saturate, and reducing the solubility of CsPbBr3; and after adding acetonitrile, the solubility of CsPbBr3 shows a monotonically decreasing trend at 25-80°C, and has a large solubility change ratio, which meets the growth requirements of CsPbBr3 single crystals; the present invention controls the initial temperature of crystal growth by the concentration of the precursor solution, so that the crystal growth process is carried out in a temperature range lower than the phase transition temperature; when the precursor solution is close to saturation, the seed crystal is added, so that the seed crystal can be partially dissolved, the interface between the seed crystal and the newly grown crystal is eliminated, and the crystal quality is improved. The results of the embodiment show that the temperature of the crystal growth performed by the growth method provided by the present invention is lower than the phase transition temperature, and a CsPbBr3 single crystal with a crystal orientation family of {110} is obtained, and the crystal has good transparency, high crystallinity, and good single orientation. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The temperature-solubility curve of CsPbBr3 in the mixed solvent of dimethyl sulfoxide and N,N-dimethylformamide prepared in Example 1;

[0021] Figure 2 The temperature-solubility curve of CsPbBr3 in the mixed solvent of dimethyl sulfoxide, N,N-dimethylformamide and acetonitrile prepared in Example 1;

[0022] Figure 3 This is a physical picture of the CsPbBr3 single crystal prepared in Example 1;

[0023] Figure 4 This is the X-ray diffraction pattern of the CsPbBr3 single crystal prepared in Example 1;

[0024] Figure 5This is a high-resolution X-ray rocking curve diagram of the CsPbBr3 single crystal prepared in Example 1. DETAILED DESCRIPTION

[0025] All raw materials of the present invention have no particular limitation on their sources and can be purchased from the market or prepared according to conventional methods known to those skilled in the art.

[0026] There is no particular limitation on the purity of all raw materials in the present invention. The present invention preferably uses analytically pure materials or materials with a purity commonly used in crystal growth.

[0027] The present invention provides a method for growing a CsPbBr3 single crystal, comprising the following steps:

[0028] 1) dissolving CsBr and PbBr2 in a mixed solvent of DMSO, DMF and ACN to obtain a CsPbBr3 precursor solution; the concentration of CsPbBr3 in the CsPbBr3 precursor solution is 0.29-0.40 g / mL; the amount of ACN added is 25-35% of the sum of the volumes of DMSO and DMF;

[0029] 2) The CsPbBr3 precursor solution obtained in step 1) is subjected to a first heating, a seed crystal is added, and then a second heating is performed to a crystallization endpoint temperature to obtain a CsPbBr3 single crystal; the endpoint temperature of the first heating is T0-(1-5)°C; T0 is the temperature at which the CsPbBr3 precursor solution reaches saturation; the crystallization endpoint temperature is not higher than 80°C.

[0030] The present invention dissolves CsBr and PbBr2 in a mixed solvent of DMSO, DMF and ACN to obtain a CsPbBr3 precursor solution.

[0031] The present invention preferably firstly mixes CsBr, PbBr2, DMSO and DMF for a coprecipitation reaction to obtain a first solution; and then mixes the first solution with ACN for a second time to obtain a CsPbBr3 precursor solution.

[0032] The present invention preferably first mixes CsBr, PbBr2, DMSO and DMF for coprecipitation reaction to obtain a first solution. ACN can reduce the solubility of CsPbBr3. The present invention first dissolves CsBr and PbBr2 in a mixed solvent of DMSO and DMF, which is conducive to the reaction of CsBr and PbBr2 to obtain CsPbBr3 without causing precipitation of CsPbBr3.

[0033] In the present invention, the molar ratio of CsBr to PbBr2 is preferably 1:(1.5-2.5), more preferably 1:2. The process of obtaining CsPbBr3 by reacting CsBr and PbBr2 is a coprecipitation reaction, and the excess PbBr2 is conducive to the reaction in the positive direction to obtain CsPbBr3; at the same time, the presence of PbBr2 in the CsPbBr3 precursor solution can also avoid the decomposition of CsPbBr3, which is conducive to the growth of crystals.

[0034] In the present invention, the volume ratio of DMSO to DMF is preferably (3-4):1, more preferably 3:1. DMF is a good solvent for CsBr and PbBr2, which is conducive to the dissolution of raw materials and obtains a uniform and stable solution; at the same time, DMF is a poor solvent for CsPbBr3, which can regulate the crystal growth rate and crystal structure. The amount relationship between DMF and DMSO is within the above range, which is conducive to the preparation of a stable solution and is conducive to improving the crystal transparency and crystal quality.

[0035] After the coprecipitation reaction is completed, the present invention preferably filters the product of the coprecipitation reaction to obtain a first solution. In the present invention, the filtration preferably uses a filter head less than 0.22 μm. The present invention removes insoluble impurities and CsPbBr3 precipitates in the raw materials by filtering, thereby improving the purity of the CsPbBr3 precursor solution and thus improving the crystal quality.

[0036] After obtaining the first solution, the present invention preferably performs a second mixing of the first solution and ACN to obtain a CsPbBr3 precursor solution.

[0037] In the present invention, the volume of ACN is 25-35% of the sum of the volumes of DMSO and DMF. As an embodiment of the present invention, the volume of ACN can be 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34% of the sum of the volumes of DMSO and DMF. ACN can reduce the solubility of CsPbBr3 and affect the law of the solubility of CsPbBr3 changing with temperature, so that the solubility of CsPbBr3 decreases monotonically below the phase transition temperature, and crystal growth is achieved below the phase transition temperature, avoiding the crystal quality of the obtained crystal being reduced due to phase transition. If the amount of ACN added is too small, the solubility of CsPbBr3 will not be greatly affected, and the crystal growth temperature cannot be reduced; if the amount added is too much, the solubility of CsPbBr3 will be too low, and crystal growth cannot be achieved. The present invention limits the amount of ACN added to the above range, and crystal growth can be carried out in the range of 25-80°C. The growth temperature is lower than the phase transition temperature, and it is conducive to obtaining high-quality crystals.

[0038] In the present invention, the concentration of CsPbBr3 in the CsPbBr3 precursor solution is 0.29-0.40 g / mL, preferably 0.35-0.37 g / mL. When the concentration of CsPbBr3 is within the above range, the raw material can be dissolved at room temperature, which is conducive to preparing a stable precursor solution, and the CsPbBr3 precursor solution is saturated at 25-60°C for crystal growth.

[0039] The CsPbBr3 precursor solution is heated for the first time, a seed crystal is added, and then a second heating is performed to the crystallization end temperature to obtain a CsPbBr3 single crystal.

[0040] The present invention preferably transfers the CsPbBr3 precursor solution to a growth bottle for the heating. The growth bottle is preferably pretreated, and the pretreatment includes: first cleaning the inner wall with deionized water, then ultrasonic cleaning with anhydrous ethanol, then washing with anhydrous ethanol, and drying for standby use; the ultrasonic cleaning time is preferably 10 to 15 minutes; the drying temperature is preferably 40 to 80°C, and the drying time is preferably 1 to 4 hours.

[0041] In the present invention, the first heating and the second heating of the CsPbBr3 precursor solution are preferably heated in an oil bath; and the medium of the oil bath is preferably silicone oil.

[0042] In the present invention, the heating rate of the first heating is preferably 5-20°C / h. The present invention heats the precursor solvent to a temperature close to T0 by the first heating, which can save heating time; T0 is the temperature when the CsPbBr3 precursor solution reaches saturation.

[0043] In the present invention, the terminal temperature of the first heating is T0-(1-5)° C., preferably T0-(1-3)° C. In the present invention, seed crystals are added when the precursor solution is close to saturation, so that the seed crystals can be partially dissolved, thereby eliminating the interface between the seed crystals and the newly grown crystals, ensuring the continuity of the crystals and improving the crystal quality.

[0044] In the present invention, the second heating includes a heating saturation stage and a crystal growth stage, which are performed in sequence; the heating saturation stage has a heating rate of 1.5 to 3°C / day; the crystal growth stage has a heating rate of 1 to 1.5°C / day. The heating saturation stage is a stage in which the precursor solution is saturated by heating. Before the precursor solution reaches saturation, the heating rate is higher, which can quickly and stably increase the temperature of the CsPbBr3 precursor solution to the initial crystallization temperature, avoiding the complete dissolution of the seed crystal due to too slow a heating rate; after the precursor solution is saturated, it enters the crystal growth stage, and reducing the heating rate at this time can make the crystal grow stably, which is beneficial to improving the crystal quality.

[0045] In the present invention, the size of the seed crystal is preferably 0.3mm×0.3mm~0.5mm×0.5mm. In the embodiment of the present invention, the size of the seed crystal is preferably 0.3mm×0.3mm. The smaller the size of the seed crystal, the smaller the interface between the seed crystal and the newly grown crystal, and the higher the crystal quality; however, if the seed crystal size is too small, it is not convenient to observe, and there is a risk of complete dissolution. The size of the seed crystal is within the above range, which is convenient for observation and avoids complete dissolution of the seed crystal, and high-quality crystals can be obtained.

[0046] In the present invention, the crystallization endpoint temperature is not higher than 80° C., preferably 40-70° C., and more preferably 45-50° C. Within the above temperature range, the CsPbBr3 solution has a good solubility change law, can be used for crystal growth, and the growth temperature is lower than the phase transition temperature of the CsPbBr3 single crystal, which is conducive to obtaining high-quality CsPbBr3 single crystals.

[0047] In the present invention, after obtaining the CsPbBr3 single crystal, it is preferred that the CsPbBr3 single crystal is taken out from the growth bottle, wiped with a dust-free cloth and then placed in a small vial, the small vial is evacuated and sealed, and stored in a dry area.

[0048] The present invention prepares a precursor solution in a mixed solvent of DMSO and DMF. By adding ACN, the clusters of ions in the precursor solution can be destroyed to make the precursor solution evenly dispersed, thereby increasing the concentration of free ions in the precursor solution, making the precursor solution more easily saturated, and reducing the solubility of CsPbBr3; and after adding ACN, the solubility of CsPbBr3 shows a monotonically decreasing trend at 25-80°C, and has a large solubility change ratio, meeting the growth requirements of CsPbBr3 single crystals; the present invention controls the initial temperature of crystal growth by the concentration of the precursor solution, so that the crystal growth temperature is lower than the phase transition temperature; adding seed crystals when the precursor solution is close to saturation can partially dissolve the seed crystals, eliminate the interface between the seed crystals and the newly grown crystals, and improve the crystal quality.

[0049] The present invention also provides a CsPbBr3 single crystal obtained by the growth method described in the above technical solution, wherein the crystal orientation family of the CsPbBr3 single crystal is {110}.

[0050] The technical solutions in the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0051] Example 1

[0052] A method for growing a CsPbBr3 single crystal, comprising the following steps:

[0053] a. Pretreatment of the growth bottle: First, treat the 20 mL growth bottle for growing crystals. Use deionized water to clean the inner wall of the growth bottle, then use an ultrasonic instrument to ultrasonicate the growth bottle for 15 minutes, then wash it with anhydrous ethanol, and then put it in a 60°C oven to dry for 2 hours for use.

[0054] b. Pre-treat the growth device: open the temperature-controlled constant temperature drying oven, put 200mL of silicone oil into a 500mL beaker, place it in the drying oven, turn on the temperature control program, start the temperature rise program to 35℃, keep warm for 2h, and preheat the silicone oil.

[0055] c. Preparation of precursor solution: 0.8938 g CsBr and 3.0828 g PbBr2 were dissolved in 9.9 mL of a mixed organic solvent of DMSO and DMF to prepare a perovskite precursor solution, wherein the volume ratio of DMSO to DMF in the mixed solvent was 3:1; the precursor solution was filtered through a 0.22 μm filter head, and 2.5 mL of ACN was added to the filtered solution for later use.

[0056] d. Use a pipette to transfer the precursor solution prepared in step c to the pre-dried growth bottle, and place the growth bottle in a preheated silicone oil beaker in a temperature-controlled constant temperature drying oven. The silicone oil in the beaker should be slightly higher than the precursor solution in the growth bottle.

[0057] e. Using the inversion crystallization method, after the precursor solution reaches 35°C, place a 0.3mm×0.3mm seed crystal in the center of the bottom of the growth bottle; increase the temperature at a rate of 2°C / day. When the seed crystal does not dissolve, change it to 1°C / day until 45°C to complete the crystal growth.

[0058] f. Take out the CsPbBr3 single crystal grown in e from the growth bottle, quickly wipe it with a dust-free cloth, store it in a small bottle, use a sealing machine to evacuate the small bottle containing the CsPbBr3 single crystal, and store it in a dry area.

[0059] Test Example 1: CsPbBr3 solubility test

[0060] A mixed solvent of DMSO and DMF was prepared according to Example 1, and the solubility of CsPbBr3 at different temperatures was measured. The results are recorded in Table 1. The temperature-solubility curve of CsPbBr3 was drawn based on the measured data, as shown in Table 1. Figure 1 As shown; according to the ratio of Example 1, ACN was added to the mixed solvent of DMSO and DMF, and the solubility of CsPbBr3 at different temperatures was measured. The results are recorded in Table 1. The temperature-solubility curve of CsPbBr3 was drawn according to the measured data, as shown in Figure 2 shown.

[0061] Table 1 Solubility of CsPbBr3 in different solvents and at different temperatures

[0062]

[0063] contrast Figure 1 and Figure 2 It can be seen that the addition of ACN makes the solubility of CsPbBr3 monotonous, and the solubility is greatly reduced, which is more conducive to the preparation of the precursor solution and reaching the initial temperature of crystal growth; moreover, the solubility has an obvious slope below the phase transition temperature, which can make the solubility of CsPbBr3 change greatly with the increase of temperature, and the seed crystal can grow quickly.

[0064] According to the formula The solubility change of CsPbBr3 in the mixed organic solvent of DMSO and DMF before and after the addition of ACN is calculated, as shown in Table 2. As can be seen from Table 2, after the addition of ACN, the solubility of CsPbBr3 in the mixed solvent changes significantly in the range of 25-80°C, indicating that after the addition of ACN, the temperature suitable for crystal growth of CsPbBr3 in the mixed solvent drops to 25-80°C, that is, crystal growth can be carried out below the phase transition temperature of CsPbBr3.

[0065] Table 2 Solubility changes before and after ACN addition

[0066]

[0067]

[0068] Test Example 2: Crystal Quality Test

[0069] The CsPbBr3 single crystal prepared in Example 1 was taken out for observation. Figure 3 As shown. Figure 3 It can be seen that the size of the crystal is 4.5mm×4.5mm and the transparency is good.

[0070] The CsPbBr3 single crystal prepared in Example 1 was subjected to an X-ray diffraction test, and the results were as follows: Figure 4 As shown. Figure 4 It can be seen that the diffraction peaks belong to the same crystal orientation group, indicating that CsPbBr3 is a single crystal and its crystal orientation group is {110}.

[0071] The CsPbBr3 single crystal prepared in Example 1 was subjected to a high-resolution X-ray sway test. The results are as follows: Figure 5 As shown. Figure 5 It can be seen that the half-height width of the crystal is relatively narrow, which is 0.0618, indicating that the crystal has high crystallinity and good single orientation.

[0072] It can be seen from the above embodiments that the present invention can reduce the solubility of CsPbBr3 by adding ACN to the precursor solution, and the solubility decreases monotonically in the range of 25 to 80°C, and the decrease is large. Crystal growth can be carried out below the phase transition temperature, and the grown CsPbBr3 single crystal has good transparency, high crystallinity, good single orientation, and the crystal orientation family is {110} single crystal.

[0073] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for growing a CsPbBr3 single crystal, characterized in that: The steps include: 1) dissolving CsBr and PbBr2 in a mixed solvent of dimethyl sulfoxide, N,N-dimethylformamide and acetonitrile to obtain a CsPbBr3 precursor solution; the concentration of CsPbBr3 in the CsPbBr3 precursor solution is 0.29-0.40 g / mL; the volume of the acetonitrile is 25-35% of the sum of the volumes of dimethyl sulfoxide and N,N-dimethylformamide; 2) The CsPbBr3 precursor solution obtained in step 1) is subjected to a first heating, a seed crystal is added, and then a second heating is performed to a crystallization endpoint temperature to obtain a CsPbBr3 single crystal; the endpoint temperature of the first heating is T0-(1-5)°C; T0 is the temperature at which the CsPbBr3 precursor solution reaches saturation; the crystallization endpoint temperature is not higher than 80°C.

2. The growth method according to claim 1, characterized in that In the step 1), the molar ratio of CsBr to PbBr2 is 1:(1.5-2.5).

3. The growth method according to claim 1, characterized in that: In the step 1), the volume ratio of dimethyl sulfoxide to N,N-dimethylformamide is (3-4):

1.

4. The growth method according to claim 1, characterized in that: In the step 1), CsBr, PbBr2, dimethyl sulfoxide and N,N-dimethylformamide are first mixed for a coprecipitation reaction to obtain a first solution; and the first solution is secondly mixed with acetonitrile to obtain a CsPbBr3 precursor solution.

5. The growth method according to claim 4, characterized in that: After the coprecipitation reaction is completed, the solution is filtered to obtain a first solution.

6. The growth method according to claim 1, characterized in that: In the step 2), the first heating and the second heating are both performed by oil bath heating.

7. The growth method according to claim 1 or 6, characterized in that: The heating rate of the first heating in step 2) is 5-20°C / h.

8. The growth method according to claim 1 or 6, characterized in that: The second heating in step 2) includes a heating saturation stage and a crystal growth stage performed sequentially; the heating rate in the heating saturation stage is 1.5-3°C / day; the heating rate in the crystal growth stage is 1-1.5°C / day.

9. The growth method according to claim 1, characterized in that: In the step 2), the size of the seed crystal is 0.3 mm×0.3 mm to 0.5 mm×0.5 mm.

10. The CsPbBr3 single crystal obtained by the growth method according to any one of claims 1 to 9, wherein the crystal orientation group of the CsPbBr3 single crystal is {110}.

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