Preparation method of halide perovskite crystal

Abstract

The invention relates to the technical field of material preparation, in particular to a preparation method of a halide perovskite crystal. Comprising the following steps: introducing ethanol in a cooling process by using a solution system cooling crystallization method, and realizing morphology control to obtain halide perovskite crystals. According to the method, the limitation of assisting morphology control by using a ligand, a surfactant, space limiting and the like in a traditional method is overcome, and the method for controllably synthesizing the ultrathin halide perovskite single crystal on a large scale is realized by utilizing crystallization kinetics control. The method has universality in halide perovskite with different structures, and makes up the blank of the synthesis technology of the halide perovskite single crystal with the two-dimensional morphology.

Description

Technical Field

[0001] The present invention relates to the technical field of material preparation, and in particular to a method for preparing a halide perovskite crystal. Background Art

[0002] Halide perovskite materials have excellent optoelectronic properties and low production costs, and have broad application prospects in the fields of solar cells, photodetectors, lasers, LED lighting, optoelectronic displays, and photocatalytic degradation. According to the crystal structure, they can be divided into 0D, 1D, and 2D perovskites composed of "vacancy-ordered" low-dimensional octahedral frameworks, and 3D perovskite materials with continuous octahedral three-dimensional space, especially 3D perovskites such as Cs 2 AG 6 It has high stability, high electron transfer rate and long carrier lifetime, as well as narrower optical band gap and wider spectral response range, making it the most promising perovskite material. Studies have shown that halide perovskites with ultra-thin two-dimensional morphology have higher carrier transmission distances, which is expected to obtain better properties.

[0003] However, due to the fast crystal growth rate and strong three-dimensional bonding characteristics of halide perovskites, it is very challenging to control the preferred growth orientation of their crystals. Although there are works such as spatial confinement method (Nat.Synth.2024,3,265) or the use of ligands (Chem.Mater.2021,33,5917) that can achieve the preparation of ultra-thin halide perovskites, the traditional method of synthesizing crystals is highly random and still cannot achieve precise control of morphology.

[0004] Therefore, it is crucial to use a simple synthetic method to achieve high-quality, large-scale, and controllable preparation of ultrathin halide perovskite crystals for their practical applications. Summary of the invention

[0005] The purpose of the present invention is to solve the problem that ultra-thin halide perovskite single crystals with two-dimensional morphology cannot be synthesized in large quantities and in a controllable manner without using space restrictions and the assistance of ligands. The present invention provides a method for preparing halide perovskite crystals.

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

[0007] The present invention provides a method for preparing a halide perovskite crystal, comprising the following steps:

[0008] A solution system cooling crystallization method is used, and an anti-solvent is introduced during the cooling process to achieve morphology control to obtain halide perovskite crystals; the anti-solvent includes one or more of methanol, ethanol and isopropanol.

[0009] Preferably, the precursor solvent used in the solution system cooling crystallization method includes hydrohalic acid and / or water;

[0010] When the precursor solvent is hydrohalic acid and water, the volume ratio of the hydrohalic acid to water is 100:32.

[0011] Preferably, the volume ratio of the precursor solvent to the anti-solvent is 1:0.1-2.

[0012] Preferably, the initial temperature of the solution system cooling crystallization method is 95°C.

[0013] Preferably, the halide perovskite crystal includes Cs 3 Bi 2 I 9 , Cs 3 Bi 2 Br 9 , Cs 3 Bi 2 Cl 9 , Cs 2 ZnCl 4 and Cs 2 AG 6 Any of .

[0014] Preferably, when the halide perovskite crystal is Cs 3 Bi 2 I 9 When, the preparation method comprises the following steps:

[0015] 1) Dissolve CsI in a precursor solvent and heat to 95° C. to obtain a precursor solution A;

[0016] The volume ratio of the molar amount of CsI to the precursor solvent is 0.45mmol:5.25mL;

[0017] The precursor solvent is HI and water, and the volume ratio of HI to water is 100:32;

[0018] 2) BiI 3 Dissolve in HI and heat to 95°C to obtain precursor solution B;

[0019] The BiI 3 The molar ratio of to HI is 0.3mmol:0.3mL;

[0020] 3) mixing the precursor solution B obtained in step 2) with an anti-solvent to obtain a precursor solution C;

[0021] The volume ratio of the precursor solution B to the anti-solvent is 1:28;

[0022] 4) Mix the precursor solution C obtained in step 3) with the precursor solution A obtained in step 1) and cool naturally to obtain Cs 3 Bi 2 I 9 .

[0023] Preferably, when the halide perovskite crystal is Cs 3 Bi 2 Br 9 When, the preparation method comprises the following steps:

[0024] 1) Dissolve CsBr in a precursor solvent and heat to 95° C. to obtain a precursor solution A;

[0025] The volume ratio of the molar amount of CsBr to the precursor solvent is 0.45mmol:5.25mL;

[0026] The precursor solvent is HBr and water, and the volume ratio of HBr to water is 100:32;

[0027] 2) BiBr 3 Dissolve in HBr and heat to 95°C to obtain precursor solution B;

[0028] The BiBr 3 The molar ratio of to HBr is 0.3mmol:0.3mL;

[0029] 3) mixing the precursor solution B obtained in step 2) with an anti-solvent to obtain a precursor solution C;

[0030] The volume ratio of the precursor solution B to the anti-solvent is 1:28;

[0031] 4) Mix the precursor solution C obtained in step 3) with the precursor solution A obtained in step 1) and cool naturally to obtain Cs 3 Bi 2 Br 9 .

[0032] Preferably, when the halide perovskite crystal is Cs 3 Bi 2 Cl 9 When, the preparation method comprises the following steps:

[0033] 1) Dissolve CsCl in a precursor solvent and heat to 95° C. to obtain a precursor solution A;

[0034] The molar ratio of CsCl to the precursor solvent is 0.45mmol:5.25mL;

[0035] The precursor solvent is HCl and water, and the volume ratio of HCl to water is 100:32;

[0036] 2) BiCl 3 Dissolve in HCl and heat to 95°C to obtain precursor solution B;

[0037] The BiCl 3 The molar ratio of to HCl is 0.3mmol:0.3mL;

[0038] 3) mixing the precursor solution B obtained in step 2) with an anti-solvent to obtain a precursor solution C;

[0039] The volume ratio of the precursor solution B to the anti-solvent is 1:28;

[0040] 4) Mix the precursor solution C obtained in step 3) with the precursor solution A obtained in step 1) and cool naturally to obtain Cs 3 Bi 2 Cl 9 .

[0041] Preferably, when the halide perovskite crystal is Cs 2 ZnCl 4 When, the preparation method comprises the following steps:

[0042] 1) Dissolve CsCl in a precursor solvent and heat to 95° C. to obtain a precursor solution A;

[0043] The volume ratio of the molar amount of CsCl to the precursor solvent is 0.2mmol:5.25mL;

[0044] The precursor solvent is HCl and water, and the volume ratio of HCl to water is 100:32;

[0045] 2) ZnCl 2 Dissolve in HCl and heat to 95°C to obtain precursor solution B;

[0046] The ZnCl 2 The molar ratio of to HCl is 0.1mmol:0.3mL;

[0047] 3) mixing the precursor solution B obtained in step 2) with an anti-solvent to obtain a precursor solution C;

[0048] The volume ratio of the precursor solution B to the anti-solvent is 1:28;

[0049] 4) Mix the precursor solution C obtained in step 3) with the precursor solution A obtained in step 1) and cool naturally to obtain Cs 2 ZnCl4 .

[0050] Preferably, when the halide perovskite crystal is Cs 2 AG 6 When, the preparation method comprises the following steps:

[0051] 1) Dissolve CsBr in a precursor solvent and heat to 95° C. to obtain a precursor solution A;

[0052] The volume ratio of the molar amount of CsBr to the precursor solvent is 0.45mmol:5.25mL;

[0053] The precursor solvent is HBr and water, and the volume ratio of HBr to water is 100:32;

[0054] 2) BiBr 3 , AgBr is dissolved in HBr and heated to 95°C to obtain precursor solution B;

[0055] The BiBr 3 , the volume ratio of AgBr to HBr is 0.3mmol:0.3mmol:2.3mL;

[0056] 3) mixing the precursor solution B obtained in step 2) with an anti-solvent to obtain a precursor solution C;

[0057] The volume ratio of the precursor solution B to the anti-solvent is 1:28;

[0058] 4) Mix the precursor solution C obtained in step 3) with the precursor solution A obtained in step 1) and cool naturally to obtain Cs 2 AG 6 .

[0059] The present invention improves the traditional cooling crystallization method by introducing an anti-solvent (methanol, ethanol, isopropanol, etc.) to regulate the crystal morphology of halide perovskite. Examples 1-5 are Cs 3 Bi 2 I 9 , Cs 3 Bi 2 Br 9 , Cs 3 Bi 2 Cl 9 , Cs 2 ZnCl 4 , Cs 2 AG 6Single crystal thin slices. This scheme uses ethanol as an anti-solvent, injects a mixed solution C containing an anti-solvent into a solution A (the solution is heated to 95°C), and after a few seconds, a large number of perovskite single crystal thin slices are suspended in the solution. The obtained sample has a regular shape, uniform crystal morphology, and high crystallinity (such as Figure 2-6 shown).

[0060] Comparative Examples 6-7 are Cs synthesized by conventional methods without using an anti-solvent. 3 Bi 2 Br 9 , Cs 2 AG 6 The specific experimental scheme is to completely dissolve the precursor in a hydrohalic acid solution, heat the solution to 95°C and then cool it naturally to room temperature. After a few hours, the crystals are removed after the crystallization is completed. The obtained crystals are irregular polyhedrons with poor crystal quality (such as Figure 7-8 shown).

[0061] Beneficial effects of the present invention:

[0062] (1) The present invention is simple to operate, does not use space restrictions and ligand assistance, can synthesize ultra-thin halide perovskite crystals in large quantities, and has high repeatability, which provides the possibility for its application in the fields of photocatalysis, optoelectronics, etc.

[0063] (2) The present invention overcomes the limitations of traditional methods on crystal structure. It can not only achieve morphology control of low-dimensional crystal structures such as "vacancy-ordered" halide perovskites, but also obtain ultra-thin single crystals of materials with 3D crystal structures. It has universal applicability and fills the gap in this field.

[0064] (3) The present invention can achieve fine control of the exposed crystal planes and morphology of halide perovskite by adjusting the anti-solvent ratio.

[0065] (4) The present invention can realize the preparation of ion-doped ultra-thin halide perovskite single crystals. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required to be used in the embodiments are briefly introduced below.

[0067] Figure 1 Schematic diagram of the experimental process of antisolvent-mediated kinetic crystal growth of halide perovskite ultra-thin single crystals;

[0068] Figure 2 Cs synthesized by antisolvent-mediated kinetic crystal growth control in the example 3 Bi 2 I 9 Optical microscope photo of single crystal thin slice;

[0069] Figure 3 Cs synthesized by antisolvent-mediated kinetic crystal growth control in the example 3 Bi 2 Br 9 Optical microscope photo of single crystal thin slice;

[0070] Figure 4 Cs synthesized by antisolvent-mediated kinetic crystal growth control in the example 3 Bi 2 Cl 9 Optical microscope photo of single crystal thin slice;

[0071] Figure 5 Cs synthesized by antisolvent-mediated kinetic crystal growth control in the example 2 ZnCl 4 Optical microscope photo of single crystal thin slice;

[0072] Figure 6 Cs synthesized by antisolvent-mediated kinetic crystal growth control in the example 2 AG 6 Optical microscope photo of single crystal thin slice;

[0073] Figure 7 Cs synthesized by conventional method in comparative example 3 Bi 2 Br 9 Crystal optical microscope photograph;

[0074] Figure 8 Cs synthesized by conventional method in comparative example 2 AG 6 Crystal optical microscope photograph;

[0075] Fig. 9 To compare the traditional method with the kinetic growth method proposed in the present invention, the Cs 3 Bi 2 Br 9 XRD patterns of crystals and photos of bulk synthesized samples. DETAILED DESCRIPTION

[0076] The present invention provides a method for preparing halide perovskite crystals, comprising the following steps: using a solution system cooling crystallization method, introducing an anti-solvent during the cooling process, achieving morphology control to obtain halide perovskite crystals; the anti-solvent comprises one or more of methanol, ethanol and isopropanol. In the present invention, the precursor solvent used in the solution system cooling crystallization method preferably comprises hydrohalic acid and / or water. In the present invention, when the precursor solvent is preferably hydrohalic acid and water, the volume ratio of the hydrohalic acid to water is preferably 100:32. In the present invention, the volume ratio of the precursor solvent to the anti-solvent is preferably 1:0.1-2. In the present invention, the initial temperature of the solution system cooling crystallization method is preferably 95°C. In the present invention, the halide perovskite crystals preferably comprise Cs 3 Bi 2 I 9 , Cs 3 Bi 2 Br 9 , Cs 3 Bi 2 Cl 9 , Cs 2 ZnCl 4 and Cs 2 AG 6 Any of .

[0077] In the present invention, when the halide perovskite crystal is Cs 3 Bi 2 I 9 When, the preparation method preferably comprises the following steps:

[0078] 1) CsI is dissolved in a precursor solvent and heated to 95° C. to obtain a precursor solution A; the volume ratio of the molar amount of CsI to the precursor solvent is 0.45 mmol:5.25 mL; the precursor solvent is HI and water, and the volume ratio of HI to water is 100:32;

[0079] 2) BiI 3 Dissolve in HI and heat to 95°C to obtain precursor solution B; the BiI 3 The molar ratio of to HI is 0.3mmol:0.3mL;

[0080] 3) mixing the precursor solution B obtained in step 2) with an anti-solvent to obtain a precursor solution C; the volume ratio of the precursor solution B to the anti-solvent is 1:28;

[0081] 4) Mix the precursor solution C obtained in step 3) with the precursor solution A obtained in step 1) and cool naturally to obtain Cs 3 Bi 2 I 9 .

[0082] In the present invention, when the halide perovskite crystal is Cs 3 Bi 2 Br 9 When, the preparation method comprises the following steps:

[0083] 1) CsBr is dissolved in a precursor solvent and heated to 95° C. to obtain a precursor solution A; the volume ratio of the molar amount of CsBr to the precursor solvent is 0.45 mmol:5.25 mL; the precursor solvent is HBr and water, and the volume ratio of HBr to water is 100:32;

[0084] 2) BiBr 3 Dissolve in HBr and heat to 95°C to obtain precursor solution B; the BiBr 3 The molar ratio of to HBr is 0.3mmol:0.3mL;

[0085] 3) mixing the precursor solution B obtained in step 2) with an anti-solvent to obtain a precursor solution C; the volume ratio of the precursor solution B to the anti-solvent is 1:28;

[0086] 4) Mix the precursor solution C obtained in step 3) with the precursor solution A obtained in step 1) and cool naturally to obtain Cs 3 Bi 2 Br 9 .

[0087] In the present invention, when the halide perovskite crystal is Cs 3 Bi 2 Cl 9 When, the preparation method preferably comprises the following steps:

[0088] 1) CsCl is dissolved in a precursor solvent and heated to 95° C. to obtain a precursor solution A; the volume ratio of the CsCl mole to the precursor solvent is 0.45 mmol:5.25 mL; the precursor solvent is HCl and water, and the volume ratio of HCl to water is 100:32;

[0089] 2) BiCl 3 Dissolve in HCl and heat to 95°C to obtain precursor solution B; the BiCl 3 The molar ratio of to HCl is 0.3mmol:0.3mL;

[0090] 3) mixing the precursor solution B obtained in step 2) with an anti-solvent to obtain a precursor solution C;

[0091] The volume ratio of the precursor solution B to the anti-solvent is 1:28;

[0092] 4) Mix the precursor solution C obtained in step 3) with the precursor solution A obtained in step 1) and cool naturally to obtain Cs 3 Bi 2 Cl 9 .

[0093] In the present invention, when the halide perovskite crystal is Cs 2 ZnCl 4 When, the preparation method preferably comprises the following steps:

[0094] 1) CsCl is dissolved in a precursor solvent and heated to 95° C. to obtain a precursor solution A; the volume ratio of the CsCl mole to the precursor solvent is 0.2 mmol:5.25 mL; the precursor solvent is HCl and water, and the volume ratio of HCl to water is 100:32;

[0095] 2) ZnCl 2 Dissolve in HCl and heat to 95°C to obtain precursor solution B; the ZnCl 2 The molar ratio of to HCl is 0.1mmol:0.3mL;

[0096] 3) mixing the precursor solution B obtained in step 2) with an anti-solvent to obtain a precursor solution C;

[0097] The volume ratio of the precursor solution B to the anti-solvent is 1:28;

[0098] 4) Mix the precursor solution C obtained in step 3) with the precursor solution A obtained in step 1) and cool naturally to obtain Cs 2 ZnCl 4 .

[0099] In the present invention, when the halide perovskite crystal is Cs 2 AG 6 When, the preparation method preferably comprises the following steps:

[0100] 1) CsBr is dissolved in a precursor solvent and heated to 95° C. to obtain a precursor solution A; the volume ratio of the molar amount of CsBr to the precursor solvent is 0.45 mmol:5.25 mL; the precursor solvent is HBr and water, and the volume ratio of HBr to water is 100:32;

[0101] 2) BiBr 3 , AgBr is dissolved in HBr and heated to 95°C to obtain a precursor solution B; the BiBr 3 , the volume ratio of AgBr to HBr is 0.3mmol:0.3mmol:2.3mL;

[0102] 3) mixing the precursor solution B obtained in step 2) with an anti-solvent to obtain a precursor solution C; the volume ratio of the precursor solution B to the anti-solvent is 1:28;

[0103] 4) Mix the precursor solution C obtained in step 3) with the precursor solution A obtained in step 1) and cool naturally to obtain Cs 2 AG 6 .

[0104] In order to further illustrate the present invention, the present invention is described in detail below in conjunction with embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0105] Example 1

[0106] Cs 3 Bi 2 I 9 The synthesis of single crystal thin films is carried out by Figure 1 The experimental flow chart shown:

[0107] CsI ​​(0.45 mmol) was dissolved in 5.25 mL HI and deionized water (the volume ratio of deionized water to HI was 100:32) and heated to 95° C. as precursor solution A.

[0108] BiI 3 (0.3 mmol) was dissolved in 0.3 mL HI and heated to 95 °C to obtain precursor solution B.

[0109] Precursor solution B and 8.325 ml of ethanol (the volume ratio of precursor solution A+B to ethanol is 1:1.5) were mixed and heated at 95° C. with stirring for 2 hours until the solution became clear, thereby obtaining precursor solution C.

[0110] The precursor solution C is quickly injected into the precursor solution A. After 1 second, floating flake single crystals appear in the solution. Then, it is naturally cooled to room temperature to obtain a large amount of Cs 3 Bi 2 I 9 For single crystal thin slices, the yield is about 90% under the condition that the volume ratio of precursor solution A+B to ethanol is 1:1.5. Figure 2 As shown, the obtained flakes are regular hexagonal in shape with a lateral dimension of about 600 μm.

[0111] Example 2

[0112] Cs 3 Bi 2 Br 9 The synthesis of single crystal thin films is carried out by Figure 1 The experimental flow chart shown:

[0113] CsBr (0.45 mmol) was dissolved in 5.25 mL of HBr and deionized water (the volume ratio of deionized water to HBr was 100:32) and heated to 95° C. as precursor solution A.

[0114] BiBr 3 (0.3 mmol) was dissolved in 0.3 mL HBr and heated to 95 °C to obtain precursor solution B.

[0115] Precursor solution B and 8.325 ml of ethanol (the volume ratio of precursor solution A+B to ethanol is 1:1.5) were mixed and heated at 95° C. with stirring for 2 hours until the solution became clear, thereby obtaining precursor solution C.

[0116] The precursor solution C is quickly injected into the precursor solution A. After one second, floating flake single crystals appear in the solution. Then, it is naturally cooled to room temperature to obtain a large amount of Cs 3 Bi 2 Br 9 For single crystal thin slices, the yield is about 80% under the condition that the volume ratio of precursor solution A+B to ethanol is 1:1.5. Figure 3 As shown, the obtained flakes are regular hexagonal in shape with a lateral dimension of about 200 μm.

[0117] Example 3

[0118] Cs 3 Bi 2 Cl 9 The synthesis of single crystal thin films is carried out by Figure 1 The experimental flow chart shown:

[0119] CsCl (0.45 mmol) was dissolved in 5.25 mL of HCl and deionized water (the volume ratio of deionized water to HCl was 100:32), and heated to 95° C. to form precursor solution A.

[0120] BiCl 3 (0.3 mmol) was dissolved in 0.3 mL HCl and heated to 95 °C to obtain precursor solution B.

[0121] Precursor solution B and 8.325 ml of methanol (the volume ratio of precursor solution A+B to methanol is 1:1.5) were mixed and heated with stirring at 95° C. for 2 hours until the solution became clear, thereby obtaining precursor solution C.

[0122] The precursor solution C is quickly injected into the precursor solution A. After one second, floating flake single crystals appear in the solution. Then, it is naturally cooled to room temperature to obtain a large amount of Cs 3 Bi 2 Cl9 For single crystal thin slices, the yield is about 80% under the condition that the volume ratio of precursor solution A+B to methanol is 1:1.5. Figure 4 As shown, the obtained flakes are in a regular rectangular shape with a longitudinal dimension of about 600 μm.

[0123] Example 4

[0124] Cs 2 ZnCl 4 The synthesis of single crystal thin films is carried out by Figure 1 The experimental flow chart shown:

[0125] CsCl (0.2 mmol) was dissolved in 5.25 mL of HCl and deionized water (the volume ratio of deionized water to HCl was 100:32) and heated to 95° C. as precursor solution A.

[0126] ZnCl 2 (0.1 mmol) was dissolved in 0.3 mL HCl and heated to 95 °C to obtain precursor solution B.

[0127] Precursor solution B and 8.325 ml of methanol (the volume ratio of precursor solution B to methanol is 1:1.5) were mixed and heated at 95° C. with stirring for 2 hours until the solution became clear, thereby obtaining precursor solution C.

[0128] The precursor solution C is quickly injected into the precursor solution A. After one second, floating flake single crystals appear in the solution, and then naturally cool to room temperature to obtain Cs 2 ZnCl 4 For single crystal thin slices, the yield is about 50% under the condition that the volume ratio of precursor solution A+B to methanol is 1:1.5. Figure 5 As shown, the obtained flakes are in a regular rectangular shape with a longitudinal dimension of about 50 μm.

[0129] Example 5

[0130] Cs 2 AG 6 The synthesis of single crystal thin films is carried out by Figure 1 The experimental flow chart shown:

[0131] CsBr (0.45 mmol) was dissolved in 5.25 mL of HBr and deionized water (the volume ratio of deionized water to HBr was 100:32) and heated to 95° C. as precursor solution A.

[0132] BiBr 3 (0.3 mmol) and AgBr (0.3 mmol) were dissolved in 2.3 mL HBr and heated to 95° C. to obtain precursor solution B.

[0133] Precursor solution B and 11.325 ml of isopropanol (the volume ratio of precursor solution A+B to isopropanol is 1:1.5) were mixed and heated with stirring at 95° C. for 2 hours until the solution became clear, thereby obtaining precursor solution C.

[0134] The precursor solution C was quickly injected into the precursor solution A. After 1 minute, floating flake single crystals appeared in the solution. Then, it was naturally cooled to room temperature to obtain a large amount of Cs 2 AG 6 For single crystal thin slices, the yield is about 70% under the condition that the volume ratio of precursor solution A+B to isopropanol is 1:1.5. Figure 6 As shown, the obtained flakes are regular hexagonal in shape with a lateral dimension of about 50 μm.

[0135] Comparative Example 1

[0136] Cs synthesized using traditional methods 3 Bi 2 Br 9 Crystal:

[0137] CsBr (0.45 mmol) was dissolved in 5.25 mL of HBr and deionized water (the volume ratio of deionized water to HBr was 100:32) and heated to 95° C. as precursor solution A.

[0138] BiBr 3 (0.3 mmol) was dissolved in 0.3 mL HBr and heated to 95 °C to obtain precursor solution B.

[0139] Quickly inject precursor solution B into precursor solution A and cool naturally to room temperature. Cs 3 Bi 2 Br 9 Polyhedral crystals, such as Figure 7 As shown, the obtained crystals are irregular in shape.

[0140] Comparative Example 2

[0141] Cs synthesized using conventional methods 2 AG 6 Crystal:

[0142] CsBr (0.45 mmol) was dissolved in 5.25 mL of HBr and deionized water (the volume ratio of deionized water to HBr was 100:32) and heated to 95° C. as precursor solution A.

[0143] BiBr 3(0.3 mmol) and AgBr (0.3 mmol) were dissolved in 2.3 mL HBr and heated to 95° C. to obtain precursor solution B.

[0144] Quickly inject precursor solution B into precursor solution A and cool naturally to room temperature. Cs 3 Bi 2 Br 9 Polyhedral crystals, such as Figure 8 As shown, the obtained crystals are irregular in shape.

[0145] Fig. 9 To compare the traditional method with the kinetic growth method proposed in the present invention, the Cs 3 Bi 2 Br 9 The XRD pattern of the crystal and the photos of the batch synthesized samples show that the crystals obtained by the present invention have strong orientation and no impurity peaks, indicating that the sample has a single component and is pure Cs 3 Bi 2 Br 9 .

[0146] Although the above embodiment describes the present invention in detail, it is only a part of the embodiments of the present invention, not all of the embodiments. People can also obtain other embodiments based on this embodiment without creativity, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for preparing a halide perovskite crystal, It is characterized in that The following steps are involved: A solution system cooling crystallization method is used, and an anti-solvent is introduced during the cooling process to achieve morphology control to obtain halide perovskite crystals; the anti-solvent includes one or more of methanol, ethanol and isopropanol.

2. The preparation method according to claim 1, It is characterized in that The precursor solvent used in the solution system cooling crystallization method includes hydrohalic acid and / or water; When the precursor solvent is hydrohalic acid and water, the volume ratio of the hydrohalic acid to water is 100:

32.

3. The preparation method according to claim 2, It is characterized in that The volume ratio of the precursor solvent to the anti-solvent is 1:0.1-2.

4. The preparation method according to claim 1, It is characterized in that The initial temperature of the solution system cooling crystallization method is 95°C.

5. The preparation method according to claim 1, It is characterized in that The halide perovskite crystal includes Cs 3 Bi 2 I 9 , Cs 3 Bi 2 Br 9 , Cs 3 Bi 2 Cl 9 , Cs 2 ZnCl 4 and Cs 2 AG 6 Any of .

6. The preparation method according to claim 5, It is characterized in that When the halide perovskite crystal is Cs 3 Bi 2 I 9 When, the preparation method comprises the following steps: 1) Dissolve CsI in a precursor solvent and heat to 95° C. to obtain a precursor solution A; The volume ratio of the molar amount of CsI to the precursor solvent is 0.45mmol:5.25mL; The precursor solvent is HI and water, and the volume ratio of HI to water is 100:32; 2) BiI 3 Dissolve in HI and heat to 95°C to obtain precursor solution B; The BiI 3 The molar ratio of to HI is 0.3mmol:0.3mL; 3) mixing the precursor solution B obtained in step 2) with an anti-solvent to obtain a precursor solution C; The volume ratio of the anti-solvent to the precursor solution B is 28:1; 4) Mix the precursor solution C obtained in step 3) with the precursor solution A obtained in step 1) and cool naturally to obtain Cs 3 Bi 2 I 9 .

7. The preparation method according to claim 5, It is characterized in that When the halide perovskite crystal is Cs 3 Bi 2 Br 9 When, the preparation method comprises the following steps: 1) Dissolve CsBr in a precursor solvent and heat to 95° C. to obtain a precursor solution A; The volume ratio of the molar amount of CsBr to the precursor solvent is 0.45mmol:5.25mL; The precursor solvent is HBr and water, and the volume ratio of HBr to water is 100:32; 2) BiBr 3 Dissolve in HBr and heat to 95°C to obtain precursor solution B; The BiBr 3 The molar ratio of to HBr is 0.3mmol:0.3mL; 3) mixing the precursor solution B obtained in step 2) with an anti-solvent to obtain a precursor solution C; The volume ratio of the precursor solution B to the anti-solvent is 1:28; 4) Mix the precursor solution C obtained in step 3) with the precursor solution A obtained in step 1) and cool naturally to obtain Cs 3 Bi 2 Br 9 .

8. The preparation method according to claim 5, It is characterized in that When the halide perovskite crystal is Cs 3 Bi 2 Cl 9 When, the preparation method comprises the following steps: 1) Dissolve CsCl in a precursor solvent and heat to 95° C. to obtain a precursor solution A; The molar ratio of CsCl to the precursor solvent is 0.45mmol:5.25mL; The precursor solvent is HCl and water, and the volume ratio of HCl to water is 100:32; 2) BiCl 3 Dissolve in HCl and heat to 95°C to obtain precursor solution B; The BiCl 3 The molar ratio of to HCl is 0.3mmol:0.3mL; 3) mixing the precursor solution B obtained in step 2) with an anti-solvent to obtain a precursor solution C; The volume ratio of the precursor solution B to the anti-solvent is 1:28; 4) Mix the precursor solution C obtained in step 3) with the precursor solution A obtained in step 1) and cool naturally to obtain Cs 3 Bi 2 Cl 9 .

9. The preparation method according to claim 5, It is characterized in that When the halide perovskite crystal is Cs 2 ZnCl 4 When, the preparation method comprises the following steps: 1) Dissolve CsCl in a precursor solvent and heat to 95° C. to obtain a precursor solution A; The volume ratio of the molar amount of CsCl to the precursor solvent is 0.2mmol:5.25mL; The precursor solvent is HCl and water, and the volume ratio of HCl to water is 100:32; 2) ZnCl 2 Dissolve in HCl and heat to 95°C to obtain precursor solution B; The ZnCl 2 The molar ratio of to HCl is 0.1mmol:0.3mL; 3) mixing the precursor solution B obtained in step 2) with an anti-solvent to obtain a precursor solution C; The volume ratio of the precursor solution B to the anti-solvent is 1:28; 4) Mix the precursor solution C obtained in step 3) with the precursor solution A obtained in step 1) and cool naturally to obtain Cs 2 ZnCl 4 .

10. The preparation method according to claim 5, It is characterized in that When the halide perovskite crystal is Cs 2 AG 6 When, the preparation method comprises the following steps: 1) Dissolve CsBr in a precursor solvent and heat to 95° C. to obtain a precursor solution A; The volume ratio of the molar amount of CsBr to the precursor solvent is 0.45mmol:5.25mL; The precursor solvent is HBr and water, and the volume ratio of HBr to water is 100:32; 2) BiBr 3 , AgBr is dissolved in HBr and heated to 95°C to obtain precursor solution B; The BiBr 3 , the volume ratio of AgBr to HBr is 0.3mmol:0.3mmol:2.3mL; 3) mixing the precursor solution B obtained in step 2) with an anti-solvent to obtain a precursor solution C; The volume ratio of the precursor solution B to the anti-solvent is 1:28; 4) Mix the precursor solution C obtained in step 3) with the precursor solution A obtained in step 1) and cool naturally to obtain Cs 2 AG 6 .

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