Method for growing FAPbBr3 single crystal in new solvent system
By using a mixed solvent system of DMF and ACN to grow FAPbBr3 single crystals, the crystal defect problem caused by FA+ decomposition was solved, and the toxic solvent GBL was replaced, achieving high-quality, green and environmentally friendly FAPbBr3 single crystal growth.
Patent Information
- Application Number
- CN202510176212.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-18
- Publication Date
- 2025-05-09
AI Technical Summary
The FA+ decomposes at high temperatures, resulting in changes in the ratio of FA+ and Pb2+ in the solution, defects in the growth crystals, and the traditional solvent GBL is toxic, affecting the green and environmental protection of the material.
FAPbBr3 single crystals are grown using a mixed solvent system of DMF and ACN. By adjusting the ratio of DMF to ACN, the saturation concentration of the solution is reduced, the inverse temperature crystallization method is achieved, FA+ decomposition is avoided, and the toxic solvent GBL is replaced.
The normal growth of FAPbBr3 single crystals in the range of 40-60℃ was achieved, which reduces crystal defects, improves the quality and safety of the material, and has a relatively rapid growth rate.
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Figure CN119956464A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a method for growing FAPbBr3 single crystals in a new solvent system, which is applied to the technical field of new material device manufacturing process for room temperature semiconductor radiation detection devices. Background Art
[0002] Metal halide perovskites have shown high photovoltaic efficiency and excellent optical properties in the field of solar cells, which has led to their extensive research. Among them, MAPbX3 (X = Cl, Br, I) perovskite materials are a hot topic, but this material will change its crystal structure at high temperatures and has stability issues, so more and more people are beginning to study alternative materials to this perovskite. Formamidinium lead halide perovskite (FAPbX3) has a similar band gap to methylammonium halide perovskite, but has excellent characteristics such as low dark current drift, high thermal stability and high phase stability, making FAPbX3 a new research focus to replace MAPbX3.
[0003] Although FAPbX3 perovskite material has good thermal stability, FA + In the precursor solution of FAPbX3, it will decompose at a temperature above 60°C, causing the FA in the solution to + With Pb 2+ The ratio of FAPbBr3 changes, resulting in defects in the grown crystals, so most FA crystals are grown at a temperature range of 40-60°C. However, the solubility of FAPbBr3 in DMF (N,N-dimethylformamide) is very high, reaching about 1.7 mol / L at 25°C. At the same time, the solubility of FAPbBr3 does not change significantly with temperature. Therefore, in existing reports, the addition of solvent GBL is often used to rapidly reduce the solubility of FAPbBr3 after heating, thereby precipitating FAPbBr3 crystals. Summary of the invention
[0004] The present invention provides a new solvent system, which adopts a mixed solvent of DMF (N,N-dimethylformamide) and ACN (acetonitrile) to grow FAPbBr3 single crystals, uses the green solvent ACN to replace the toxic solvent GBL, and by adjusting the ratio of DMF to ACN, the FAPbBr3 single crystal can be grown normally in the range of 40-60°C.
[0005] In order to achieve the above invention purpose, the present invention adopts the following technical solutions:
[0006] First, dissolve FABr and PbBr2 in the organic solvent DMF in a ratio of 1:1, then stir the precursor solution until it is clear and transparent, and filter the precursor solution into a clean growth bottle using a 0.22μm filter head; then add an appropriate amount of ACN to the precursor solution to reduce the saturation concentration of the solution so that the precursor solution reaches saturation; then transfer the prepared precursor solution to a 20ml glass growth bottle, put in the seed crystal and place it in a temperature-controlled constant temperature drying oven to heat and grow crystals.
[0007] The new solvent system grows FAPbBr3 single crystals. The specific steps are as follows:
[0008] (1) Dissolve FABr and PbBr2 simultaneously in a mixed organic solvent of DMF and ACN, with the molar ratio of FABr to PbBr2 being 1:1; and stir the precursor solution sufficiently to completely dissolve the solute.
[0009] (2) The prepared precursor solution is transferred to a growth bottle, and a seed crystal is placed at the bottom of the growth bottle. The temperature of the precursor solution is increased by adjusting the temperature so that the seed crystal placed in the growth bottle begins to grow slowly, thereby obtaining a FAPbBr3 single crystal.
[0010] Preferably, the molar ratio of FABr to PbBr2 is 1:1.
[0011] Preferably, in the DMF / ACN mixed organic solvent, 1.6-1.9 ml of ACN is added to every 5.1 ml of DMF mixed solvent.
[0012] Preferably, the size of the seed crystal is 0.5×0.5×0.3 cm 3 .
[0013] Preferably, the specific process of adjusting the temperature is: starting from 40°C, the temperature is increased by 1°C / 6h, then by 1-2°C, and then by 1°C / day until the FAPbBr3 seed crystal placed in the precursor solution grows to a suitable size and is taken out, thereby ending crystal growth.
[0014] Beneficial effects of the present invention:
[0015] (1) The use of a new DMF+ACN solvent system can rapidly reduce the solubility of the precursor solution, making it more suitable for growing FAPbBr3 single crystals using the inversion crystallization method.
[0016] (2) Compared with the pure DMF solvent system, it is impossible to obtain FAPbBr3 single crystals by inversion growth. When the DMF+GBL solvent system is used to grow FAPbBr3 single crystals, GBL is a toxic solvent. The use of this new DMF+ACN solvent system is greener and safer, and the quality of the FAPbBr3 single crystals grown is also higher.
[0017] (3) The new DMF+ACN solvent system can be used to grow FAPbBr3 single crystals at a relatively fast speed, and larger and better FAPbBr3 single crystals can be grown in about 7-8 days. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 This is a physical picture of sample 1FAPbBr3 single crystal.
[0019] Figure 2 This is the X-ray diffraction pattern of sample 1FAPbBr3 crystal.
[0020] Figure 3 X-ray rocking curve test of sample 1FAPbBr3 crystal. DETAILED DESCRIPTION
[0021] 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 contents described above.
[0022] The method described in the present invention is: using a new solvent system to grow organic-inorganic perovskite FAPbBr3 single crystals using an inversion crystallization method, first preparing a FAPbBr3 precursor solution, mixing FABr and PbBr2 in a mixed solvent of DMF and ACN in a ratio of 1:1, and fully stirring the prepared precursor solution for 6-8 hours to ensure sufficient solubility of the raw materials; then transferring the prepared precursor solution to a 20ml glass growth bottle, placing a seed crystal in it and placing it in a temperature-controllable constant temperature drying oven to heat and grow crystals.
[0023] Example 1
[0024] A method for growing an organic-inorganic perovskite FAPbBr3 single crystal specifically comprises the following steps:
[0025] (1) Pretreatment of the growth device: 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, and then put it in an oven to dry for use.
[0026] (2) Pre-treatment of the crystal growth equipment: Open a temperature-controlled constant temperature drying oven, put silicone oil into a 500 ml beaker, place it in the drying oven, and then start the temperature control program to preheat the silicone oil.
[0027] (3) Preparation of FAPbBr3 precursor solution: FABr and PbBr2 were dissolved in a mixed solvent of DMF and ACN at a molar ratio of 1:1, and the precursor solution was stirred for 8 hours until it became clear and transparent to ensure that the solute was completely dissolved. The precursor solution was filtered through a 0.22 μm filter head and set aside.
[0028] (4) Use a pipette to transfer the precursor solution prepared in the previous step to a pre-dried growth bottle, and place a FAPbBr3 seed crystal in the center of the bottom of the growth bottle. Place the growth bottle in a silicone oil beaker in a preheated, temperature-controlled constant temperature drying oven, so that the silicone oil in the beaker is just slightly higher than the precursor solution in the growth bottle.
[0029] (5) Then, the temperature of the temperature-controlled constant temperature drying oven is increased to raise the temperature of the precursor solution so that the seed crystal placed in the growth bottle begins to grow slowly. The temperature is increased from 40°C at 1°C / day until the FAPbBr3 seed crystal placed in the growth bottle grows to a suitable size (about 5×5mm), and the crystal growth is terminated. The crystal is taken out and quickly wiped with a dust-free cloth, and then placed in a small bottle for storage. The small bottle containing the perovskite single crystal is evacuated with a sealing machine and placed in a dry area for storage.
[0030] In the DMF and ACN mixed solvent, about 1.6-1.9 ml of ACN was added to every 5.1 ml of DMF solvent.
[0031] In the DMF and ACN mixed solvent, the order of adding DMF and ACN is to first use DMF as a solvent to dissolve the raw materials, then stir and clarify, and then add ACN to make the precursor solution quickly reach saturation. After the precursor solution is shaken evenly, the next step is performed.
[0032] The actual picture of the FAPbBr3 single crystal sample prepared in this example is as follows Figure 1 As shown. It can be seen that the transparency of the grown FAPbBr3 single crystal is very high. Then the grown FAPbBr3 single crystal is analyzed by X-ray diffractometer. The results are as follows Figure 2 As shown in the figure, the XRD pattern of FAPbBr3 single crystal has a total of 4 diffraction peaks, and the angles corresponding to each diffraction peak are also multiples, indicating that they are from the same crystal plane. Then the X-ray rocking curve is used to test the crystallization of the grown FAPbBr3 single crystal, as shown in the figure. Figure 3 The XRC test result of FAPbBr3 single crystal is 0.164°, which indicates that the grown FAPbBr3 crystal has high crystallinity and good crystal quality.
[0033] Comparative Example 1
[0034] Compare the growth of FAPbBr3 single crystals using a single DMF system and a single ACN system.
[0035] The specific steps include:
[0036] (1) Pretreatment of the growth device: 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 10-15 minutes. Then use anhydrous ethanol to wash it several times, and then put it in an oven to dry for use.
[0037] (2) Pre-treatment of the crystal growth equipment: Open a temperature-controlled constant temperature drying oven, put silicone oil into a 500 ml beaker, place it in the drying oven, and then start the temperature control program to preheat the silicone oil.
[0038] (3) Preparation of FAPbBr3 precursor solution: FABr and PbBr2 were dissolved in two organic solvents, DMF and ACN, respectively, at a molar ratio of 1:1 to obtain two bottles of precursor solutions under different solvent systems (referred to as DMF system and ACN system). The two bottles of precursor solutions were then fully stirred for 6-8 hours, and then the precursor solutions were filtered using a 0.22 μm filter head for later use.
[0039] (4) Use a pipette to transfer the precursor solution prepared in the previous step to a pre-dried growth bottle, and place a FAPbBr3 seed crystal in the center of the bottom of the growth bottle. Place the growth bottle in a silicone oil beaker in a preheated temperature-controlled constant temperature drying oven, so that the silicone oil in the beaker is just slightly higher than the precursor solution in the growth bottle.
[0040] (5) Then, the temperature of the temperature-controlled constant temperature drying oven is increased to raise the temperature of the precursor solution so that the seed crystal placed in the growth bottle begins to grow slowly. The temperature is increased from 40°C at 1°C / day until the FAPbBr3 seed crystal placed in the growth bottle grows to a suitable size (about 5×5mm), and the crystal growth is terminated. The crystal is taken out and quickly wiped with a dust-free cloth, and then placed in a small bottle for storage. The small bottle containing the perovskite single crystal is evacuated with a sealing machine and placed in a dry area for storage.
[0041] This example is used as a comparison. Except for using a different solvent system, the remaining operating steps are consistent with the operating steps of Example 1.
[0042] The crystals grown in the mixed solvent system of DMF and ACN in Example 1 were recorded as Sample 1.
[0043] Sample 2 was obtained by replacing the DMF and ACN mixed solvent in Comparative Example 1 with DMF solvent.
[0044] The mixed solvent of DMF and ACN in Comparative Example 1 was replaced with ACN solvent to obtain Sample 3.
[0045] Analyze and compare the results of each example:
[0046] Sample 1 obtained better FAPbBr3 single crystal.
[0047] Since the solubility of FAPbBr3 in DMF of sample 2 is very high and the solubility does not change significantly with temperature, after the temperature is raised to 60°C or even to a higher temperature, FAPbBr3 single crystals are still not precipitated from the precursor solution.
[0048] In sample 3, since the solubility of FABr and PbBr2 in ACN is very low, the raw materials are almost not dissolved, so effective FAPbBr3 crystals cannot be obtained.
[0049] Comparing the results of various solvent systems, only when the DMF+ACN solvent system is used can better FAPbBr3 single crystals be obtained.
Claims
1. A method for growing FAPbBr3 single crystals using a new solvent system, characterized in that: The specific steps include: (1) dissolving FABr and PbBr2 simultaneously in a mixed organic solvent of N,N-dimethylformamide and acetonitrile, and stirring sufficiently to completely dissolve the solute to obtain a precursor solution; (2) The prepared precursor solution is transferred to a growth bottle, and a seed crystal is placed at the bottom of the growth bottle. The temperature of the precursor solution is increased by adjusting the temperature so that the seed crystal placed in the growth bottle begins to grow slowly, thereby obtaining a FAPbBr3 single crystal.
2. The method for growing FAPbBr3 single crystals using the new solvent system according to claim 1, characterized in that: The molar ratio of FABr to PbBr2 is 1:
1.
3. The method for growing FAPbBr3 single crystals using the new solvent system according to claim 1, characterized in that: In a mixed organic solvent of N,N-dimethylformamide and acetonitrile, add 1.8-1.9 ml of acetonitrile to every 5.1 ml of N,N-dimethylformamide solvent.
4. The method for growing FAPbBr3 single crystals using the new solvent system according to claim 1, characterized in that: The specification of the seed crystal is 0.5×0.5×0.3cm 3 .
5. The method for growing FAPbBr3 single crystals using the new solvent system according to claim 1, characterized in that: The specific process of adjusting the temperature is: starting from 40°C, the temperature is increased by 1°C / 6h, then by 1-2°C, and then by 1°C / day until the FAPbBr3 seed crystal placed in the precursor solution grows to a suitable size and is taken out, thereby ending the crystal growth.