Preparation method of CsPbBr3 single crystal
By introducing methanol and BBA into the precursor solution of CsPbBr3, the slope of the solubility curve and the crystal quality are reduced, and the problems of high growth temperature and phase transition in traditional inversion crystallization are solved, and the growth of high-quality CsPbBr3 single crystals is achieved.
Patent Information
- Application Number
- CN202510175809.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-18
- Publication Date
- 2025-05-06
AI Technical Summary
The temperature of CsPbBr3 is grown in the traditional inversion crystallization method is high and there is a phase change problem, resulting in a deterioration in crystal quality.
By introducing methanol and 4-bromobutyric acid (BBA) as additives in the precursor solution, the slope of the solubility curve is reduced and the crystal quality is improved, and CsPbBr3 is precipitated at a lower temperature by reducing the growth temperature.
The growth of high-quality CsPbBr3 single crystals at lower temperatures is achieved, reducing the risk of phase transition and microcracking of the crystals.
Smart Images
Figure CN119932690A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a method for preparing a CsPbBr3 single crystal, belonging to the technical field of novel nanomaterials. Background Art
[0002] At present, the application demand of low-temperature semiconductor radiation detection devices is increasing, and they have important application prospects in various fields such as medical diagnosis, clinical treatment, environmental monitoring, and aerospace. The room temperature radiation detection materials currently used include CZT, TlBr and HgI2, but these materials either have stability problems or cost problems, and therefore cannot be mass-produced and applied.
[0003] In recent years, metal halide perovskite single crystals have the advantages of adjustable band gap, extremely low trap density, long diffusion length, high carrier mobility and long life, which makes the radiation detectors made of single crystals have good energy resolution, high stability and sensitivity. Among them, CsPbBr3 perovskite has good performance and has attracted attention. However, there is a phase transition problem when growing CsPbBr3. Below 88℃, it is an orthorhombic phase, above 130℃, it is a cubic phase, and between 88 and 130℃, it is a tetragonal phase. The temperature of growing CsPbBr3 by the traditional inversion crystallization method is between 90 and 130℃, which causes the crystal to undergo a phase transition when it is taken out and cooled to room temperature. The stress generated by the phase transition causes microcracks in the grown crystal, resulting in poor quality of the grown crystal. Summary of the invention
[0004] In view of the high temperature of growing CsPbBr3 and the phase change that causes the crystal to deteriorate due to the traditional inversion crystallization method, the present invention uses methanol and 4-bromobutyric acid (BBA) as additives and introduces them into the precursor solution. On the one hand, the introduction of methanol can reduce the solubility of the precursor solution, and at the same time, reduce the slope of the solubility curve between 85 and 90°C, thereby reducing the growth rate of CsPbBr3 and improving the crystal quality; on the other hand, the introduction of BBA makes the solubility curve decrease monotonically, which allows CsPbBr3 to precipitate after room temperature, thereby reducing the growth temperature. High-quality CsPbBr3 crystals are grown through the process of the present invention.
[0005] In order to achieve the above invention purpose, the present invention adopts the following technical solutions:
[0006] (1) Dissolve cesium bromide and lead bromide in dimethyl sulfoxide solvent, add 4-bromobutyric acid, and add to the mixed solution I under cooling and stirring.
[0007] (2) Thoroughly mix anhydrous methanol, cyclohexanol and dimethylformamide to obtain a mixed solution II.
[0008] (3) The mixed solution I and the mixed solution II are fully mixed in a water bath and then filtered to obtain a precursor solution.
[0009] (4) A seed crystal is placed in the precursor solution, and then the precursor solution and the container are placed in preheated silicone oil to prepare a CsPbBr3 single crystal by a temperature inversion crystallization method.
[0010] Preferably, in step (1), the amount of cesium bromide added to the DMSO solvent is 0.4-0.46 mmol / mL; the molar ratio of cesium bromide, lead bromide and 4-bromobutyric acid is 1:2:(0.126-0.128).
[0011] Preferably, in step (2), the volume ratio of anhydrous methanol, cyclohexanol and DMF is 1:2:4.
[0012] Preferably, in step (3), the volume ratio of mixed solution I to mixed solution II is (1.5-1.8):1.
[0013] Preferably, the temperature of the water bath in step (3) is 50-55° C., and the filter used for filtration is polytetrafluoroethylene with a pore size of 0.22 mm.
[0014] Preferably, the size of the seed crystal in step (4) is 0.5×0.5×0.3 cm 3
[0015] Preferably, the temperature of the silicone oil preheated in step (4) is 58-60°C.
[0016] Preferably, the conditions of the inversion crystallization method in step (4) are: starting from 50-61°C, the heating rate is 1°C / h, when the seed crystal is not dissolved, the temperature is increased at a rate of 2°C / day, and when the seed crystal grows to the centimeter level, the crystal is taken out.
[0017] Technical Effects of the Invention
[0018] On the one hand, the introduction of methanol can reduce the solubility of the precursor solution and, at the same time, reduce the slope of the solubility curve between 55 and 85°C, thereby reducing the growth rate of CsPbBr3 and improving the crystal quality; on the other hand, the introduction of BBA makes the solubility curve monotonically decrease, which allows CsPbBr3 to precipitate at around 60°C, thereby reducing the growth temperature. High-quality CsPbBr3 single crystals are grown through the process of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1 This is a physical picture of the CsPbBr3 single crystal prepared in Example 1.
[0020] Figure 2This is the X-ray diffraction pattern of the CsPbBr3 single crystal prepared in Example 1.
[0021] Figure 3 This is a high-resolution X-ray rocking (XRC) curve of the CsPbBr3 single crystal prepared in Example 1.
[0022] Figure 4 The solubility of CsPbBr3 of Comparative Example 1 and Comparative Example 2 in DMSO, DMF and cyclohexanol.
[0023] Figure 5 is the solubility of CsPbBr3 in Example 1 in DMSO, DMF and cyclohexanol. DETAILED DESCRIPTION
[0024] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments, but the protection scope of the present invention is not limited to the described contents.
[0025] Example 1
[0026] A method for preparing a CsPbBr3 single crystal specifically comprises the following steps:
[0027] (1) Preparation: First, treat the 20 ml growth bottle for growing crystals. Use deionized water to clean the inner wall of the growth bottle. Then use anhydrous ethanol to ultrasonically treat the growth bottle for 15 minutes. Then use anhydrous ethanol to wash it several times. Then put it in an oven to dry for use. Then, pre-treat the crystal growth equipment. Open the temperature-controlled constant temperature drying oven. Take two large beakers and put silicone oil in them. Put them in the drying oven. Then turn on the temperature control program and start the temperature increase program to 58°C so that the silicone oil in the beaker is heated to 58°C.
[0028] (2) 3.07 mmol of cesium bromide and 6.14 mmol of lead bromide were dissolved in 6.7 mL of DMSO solvent, and 0.39 mmol of BBA (4-bromobutyric acid) was added. The mixture was heated and stirred in a water bath at 60° C. to obtain a mixed solution I.
[0029] (3) 0.52 ml of anhydrous methanol, 1.2 ml of cyclohexanol and 2.2 ml of DMF were added to a sample bottle and stirred at room temperature for 2 h to mix them thoroughly to obtain a mixed solution II.
[0030] (4) Mix the mixed solution I obtained in step (2) and the mixed solution II obtained in step (3), continue stirring in a 50° C. water bath for 2 h, and filter the solution with a polytetrafluoroethylene filter with a pore size of 0.22 mm to obtain the desired precursor solution.
[0031] (5) Transfer the precursor solution obtained in step (4) to a pre-dried growth bottle, and place a seed crystal in the center of the bottom of the growth bottle. Place the growth bottle containing the precursor solution into the silicone oil in a temperature-controllable constant temperature drying oven, allowing the silicone oil in the beaker to completely immerse the precursor solution in the growth bottle.
[0032] (6) Using the inversion crystallization method, the temperature was raised from 58°C at a rate of 1°C / h. When the seed crystal did not dissolve, the temperature was raised at a rate of 2°C / day until the seed crystal grew to the centimeter level. The crystal was then taken out to obtain a CsPbBr3 single crystal.
[0033] (7) The CsPbBr3 single crystal obtained in step (6) is cleaned with DMF solvent, and then the precursor solution remaining on the surface of the crystal is removed with a dust-free cloth to obtain high-quality CsPbBr3 crystals. Next, a sealing machine is used to vacuum seal the sample bottle containing the CsPbBr3 single crystal and store it in a dry area.
[0034] The physical image, X-ray diffraction (XRD) pattern and high-resolution X-ray rocking (XRC) curve of CsPbBr3 crystal obtained in this example are as follows: Figure 1 , Figure 2 and Figure 3 shown. Figure 1 The CsPbBr3 single crystal grown by introducing two additives, anhydrous methanol and BBA (4-bromobutyric acid), has good transparency; Figure 2 The single crystal X-ray diffraction (XRD) pattern shown indicates that the grown CsPbBr3 crystals are pure orthorhombic phase; Figure 3 The single crystal high-resolution X-ray rocking curve (XRC) shown is narrow, indicating that the crystal structure obtained by introducing additive growth is more complete, the lattice distortion is less, and the crystal quality is higher.
[0035] Comparative Example 1
[0036] For comparison, the difference between this comparative example and Example 1 is that anhydrous methanol and BBA (4-bromobutyric acid) are not added, and the remaining steps and reagent dosages are the same as those in Example 1. The specific preparation steps are as follows:
[0037] (1) Preparation: First, treat the 20 ml growth bottle for growing crystals. Use deionized water to clean the inner wall of the growth bottle. Then use anhydrous ethanol to ultrasonically treat the growth bottle for 15 minutes. Then use anhydrous ethanol to wash it several times. Then put it in an oven to dry for use. Then, pre-treat the crystal growth equipment. Open the temperature-controlled constant temperature drying oven. Take two large beakers and put silicone oil in them. Put them in the drying oven. Then turn on the temperature control program and start the temperature increase program to 58°C so that the silicone oil in the beaker is heated to 58°C.
[0038] (2) 3.07 mmol of cesium bromide and 6.14 mmol of lead bromide were dissolved in 6.7 mL of DMSO solvent, and the mixture was heated and stirred in a water bath at 60° C. to obtain a mixed solution I.
[0039] (3) 1.2 ml of cyclohexanol and 2.2 ml of DMF were added to a sample bottle and stirred at room temperature for 2 h to mix them thoroughly to obtain a mixed solution II.
[0040] (4) Mix the mixed solution I obtained in step (2) and the mixed solution II obtained in step (3), continue stirring in a 50° C. water bath for 2 h, and filter the solution with a polytetrafluoroethylene filter with a pore size of 0.22 mm to obtain the desired precursor solution.
[0041] (5) Transfer the precursor solution obtained in step (4) to a pre-dried growth bottle, and place a seed crystal in the center of the bottom of the growth bottle. Place the growth bottle containing the precursor solution into the silicone oil in a temperature-controllable constant temperature drying oven, allowing the silicone oil in the beaker to completely immerse the precursor solution in the growth bottle.
[0042] (6) Using the inversion crystallization method, the temperature is raised from 96°C at a rate of 1°C / h. When the seed crystal does not dissolve, the temperature is raised at a rate of 2°C / day until the seed crystal grows to the centimeter level. The crystal is then taken out to obtain a CsPbBr3 single crystal.
[0043] (7) The CsPbBr3 single crystal obtained in step (6) is cleaned with DMF solvent, and then the precursor solution remaining on the surface of the crystal is removed with a dust-free cloth to obtain high-quality CsPbBr3 crystals. Next, a sealing machine is used to vacuum seal the sample bottle containing the CsPbBr3 single crystal and store it in a dry area.
[0044] Comparative Example 2
[0045] For comparison, the difference between this comparative example and Example 1 is that BBA (4-bromobutyric acid) is not used, and the remaining steps and reagent dosages are the same as those in Example 1. The specific preparation steps are as follows:
[0046] (1) Preparation: First, treat the 20 ml growth bottle for growing crystals. Use deionized water to clean the inner wall of the growth bottle. Then use anhydrous ethanol to ultrasonically treat the growth bottle for 15 minutes. Then use anhydrous ethanol to wash it several times. Then put it in an oven to dry for use. Then, pre-treat the crystal growth equipment. Open the temperature-controlled constant temperature drying oven. Take two large beakers and put silicone oil in them. Put them in the drying oven. Then turn on the temperature control program and start the temperature increase program to 58°C so that the silicone oil in the beaker is heated to 58°C.
[0047] (2) 3.07 mmol of cesium bromide and 6.14 mmol of lead bromide were dissolved in 6.7 mL of DMSO solvent, and the mixture was heated and stirred in a water bath at 60° C. to obtain a mixed solution I.
[0048] (3) 0.52 ml of anhydrous methanol, 1.2 ml of cyclohexanol and 2.2 ml of DMF were added to a sample bottle and stirred at room temperature for 2 h to mix them thoroughly to obtain a mixed solution II.
[0049] (4) Mix the mixed solution I obtained in step (2) and the mixed solution II obtained in step (3), continue stirring in a 50° C. water bath for 2 h, and filter the solution with a polytetrafluoroethylene filter with a pore size of 0.22 mm to obtain the desired precursor solution.
[0050] (5) Transfer the precursor solution obtained in step (4) to a pre-dried growth bottle, and place a seed crystal in the center of the bottom of the growth bottle. Place the growth bottle containing the precursor solution into the silicone oil in a temperature-controllable constant temperature drying oven, allowing the silicone oil in the beaker to completely immerse the precursor solution in the growth bottle.
[0051] (6) Using the inversion crystallization method, the temperature is raised from 60°C at a rate of 1°C / h. When the seed crystal does not dissolve, the temperature is raised at a rate of 2°C / day until the seed crystal grows to the centimeter level. The crystal is then taken out to obtain a CsPbBr3 single crystal.
[0052] (7) The CsPbBr3 single crystal obtained in step (6) is cleaned with DMF solvent, and then the precursor solution remaining on the surface of the crystal is removed with a dust-free cloth to obtain high-quality CsPbBr3 crystals. Next, a sealing machine is used to vacuum seal the sample bottle containing the CsPbBr3 single crystal and store it in a dry area.
[0053] Experimental test analysis
[0054] The solubility curves of CsPbBr3 in the mixed solvent of DMSO, DMF and cyclohexanol in Example 1, Comparative Example 1 and Comparative Example 2 were measured. The results are as follows: Figure 1 and Figure 2 As shown, combined Figure 1 and Figure 2 It can be seen that the slope of the solubility curve decreases after the introduction of methanol, which reduces the crystal growth rate. The introduction of BBA causes the solubility of CsPbBr3 to decrease monotonically. Therefore, using BBA and methanol as additives can enable CsPbBr3 to grow at a lower temperature, and the quality of CsPbBr3 single crystals prepared using methanol and BBA is better.
Claims
1. A method for preparing a CsPbBr3 single crystal, characterized in that: The preparation method comprises the following steps: (1) Dissolve cesium bromide and lead bromide in dimethyl sulfoxide solvent, add 4-bromobutyric acid, and heat and stir to mix the solution I; (2) fully mixing anhydrous methanol, cyclohexanol and dimethylformamide to obtain a mixed solution II; (3) Mixing the mixed solution I and the mixed solution II in a water bath and filtering them to obtain a precursor solution; (4) A seed crystal is placed in the precursor solution, and then the precursor solution and the container are placed in preheated silicone oil to prepare a CsPbBr3 single crystal by a temperature inversion crystallization method.
2. The method for preparing CsPbBr3 single crystal according to claim 1, characterized in that: In step (1), the amount of cesium bromide added to the DMSO solvent is 0.4-0.46 mmol / mL; the molar ratio of cesium bromide, lead bromide and 4-bromobutyric acid is 1:2:(0.126-0.128).
3. The method for preparing CsPbBr3 single crystal according to claim 1, characterized in that: In step (2), the volume ratio of anhydrous methanol, cyclohexanol and DMF is 1:2:
4.
4. The method for preparing CsPbBr3 single crystal according to claim 1, characterized in that: In step (3), the volume ratio of mixed solution I to mixed solution II is (1.5-1.8):
1.
5. The method for preparing CsPbBr3 single crystal according to claim 1, characterized in that: In step (3), the temperature of the water bath is 50-55° C., and the filter used for filtering is polytetrafluoroethylene with a pore size of 0.22 mm.
6. The method for preparing CsPbBr3 single crystal according to claim 1, characterized in that: The size of the seed crystal in step (4) is 0.5×0.5×0.3 cm 3 .
7. The method for preparing CsPbBr3 single crystal according to claim 1, characterized in that: The temperature of the silicone oil preheated in step (4) is 58-60°C.
8. The method for preparing CsPbBr3 single crystal according to claim 1, characterized in that: The conditions of the inversion crystallization method in step (4) are: starting from 50-61°C, the heating rate is 1°C / h. When the seed crystal does not dissolve, the temperature is increased at a rate of 2°C / day. When the seed crystal grows to the centimeter level, the crystal is taken out.