A halide perovskite micro-nano array structure and preparation method thereof

Abstract

The present invention provides a halide perovskite micro-nano array structure and a preparation method thereof, which belongs to the field of new semiconductor optoelectronic materials. A surfactant-assisted liquid phase crystallization method is adopted, and a high-quality single-crystal halide perovskite micro-nano array structure can be directly prepared without any micro-nano processing technology. The prepared perovskite micro-nano array structure is composed of tens to hundreds of horizontally arranged micrometer wires or nanowires, and its length can be controllably adjusted between tens to hundreds of micrometers, its width can be controllably adjusted between tens of nanometers and tens of micrometers, and its thickness can be controllably adjusted between tens of nanometers and hundreds of nanometers. The present invention realizes the array completely through atomic self-assembly, without any template, photolithography, electron beam etching and other micro-nano processing technology; it has low cost and high controllability, and has wide application potential in semiconductor optoelectronic and photovoltaic devices such as halide perovskite array photoelectric sensors, light-emitting diodes and solar cells.

Description

Technical Field

[0001] The invention belongs to the field of semiconductor optoelectronic materials and relates to a halide perovskite micro-nano array structure and a preparation method thereof. Background Art

[0002] Perovskite materials have unique physical and chemical properties: long carrier diffusion length, high carrier mobility, high defect tolerance, adjustable band gap, etc. As of August 2022, the energy conversion efficiency of solar cells based on halide perovskite materials has exceeded 25.6%. At the same time, perovskite materials also have good application potential in light-emitting devices. Their fluorescence quantum efficiency can be as high as nearly 100%, the half-peak width can reach less than 15nm, and the full spectrum is adjustable in the visible light range (400-750nm). Halide perovskites have rapidly become one of the most promising materials in the 21st century, showing very promising application prospects in many fields such as photovoltaics, LEDs, lasers, memory, memristors, transistors, photodetectors and photocatalysis.

[0003] One-dimensional perovskite nano / microwire structures have higher crystallinity, fewer defects and grain boundaries than polycrystalline films, and therefore exhibit longer carrier diffusion lengths and higher carrier mobility, resulting in excellent charge transport performance. This one-dimensional perovskite nano / microwire structure has anisotropic optical properties, which can be used as a polarization-sensitive photodetector, which plays a great role in the applications of integrated photonic circuits, optical switches, near-field imaging, and high-resolution detection. Due to the large specific surface area, the ion exchange reaction of the one-dimensional perovskite nano / microwire structure is usually faster than that in bulk materials, and simple heteroepitaxial integration can be performed in a single nanostructure. Because perovskite nano / microwires have controllable sizes and well-defined facets, lasers are also a widely studied optoelectronic device. In addition, due to the one-dimensional geometry with a high aspect ratio, one-dimensional perovskite materials show excellent mechanical flexibility, which is conducive to the manufacture of flexible devices. In addition, low-dimensional perovskites perform better than polycrystalline perovskites in terms of phase stability, environmental stability, mechanical stability, and suppression of ion migration.

[0004] In recent years, halide perovskite nano / micro array structures with periodic structures have attracted widespread attention from researchers. Halide perovskite nano / micro array structures not only improve the performance of devices, but also reveal unprecedented functions such as anisotropy and directional optoelectronic properties. Perovskite nano / micro wire arrays can act as micro gratings to provide additional light management for light detection. In addition to the normal light signal collection function, the combination of additional multifunctionality (flexibility, self-powered and polarized light detection) has also stimulated extensive research interest. Nano / micro wire array structures can also be used in solar cells to optimize light absorption. The preparation of perovskite nano / micro wire arrays plays a vital role in the development of future photovoltaic and optoelectronic devices. At present, the preparation methods of nano / micro wire array structures are divided into top-down and bottom-up. The top-down methods mainly include photolithography, focused ion beam etching, focused electron beam exposure PMMA template, direct laser ablation, etc. These top-down methods have the advantages of being able to directly delete selected areas and write on demand, but light and electron beams can cause damage such as deformation of the crystal structure and introduction of defects, while ion implantation can cause amorphization of perovskite crystals. In addition, in template lithography technology, high-resolution patterns cannot be achieved due to the difficult-to-eliminate gap between the template and the substrate. Bottom-up methods mainly include nanoimprinting, transfer printing, capillary molding and inkjet printing, which are cost-effective, high-throughput and high-speed, and have reliable accuracy over large areas (greater than centimeter scale). Crystal materials prepared by epitaxial growth have low defect density, but the crystal position controllability is poor. Molecular self-assembly to generate ordered nanostructures can break through the minimum size limit of pattern transfer technology. Various studies using self-assembled nanostructures have established sub-100nm scale patterns in various systems, such as block copolymers, supramolecules, inorganic porous membranes and colloids. Reducing the resolution to below 100nm will have a significant impact on radiation emission, ultra-high density devices and new optical structures. It may also be a good idea to combine molecular self-assembly with traditional lithography technology. Summary of the invention

[0005] In view of the problems existing in the existing synthesis technology, the present invention aims to synthesize halide perovskite micro-nano array structures safely, at low cost, simply and efficiently under ambient conditions. The prepared halide perovskite micro-nano array has controllable morphology, orderly arrangement and consistent orientation, and can be further transferred to other substrates using polydimethylsiloxane (PDMS) to achieve customization of optoelectronic devices.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A method for preparing a halide perovskite micro-nano array structure, using a liquid-phase reverse solvent-assisted crystallization method, comprises the following steps:

[0008] Step 1: Prepare ABX3 perovskite precursor solution at room temperature

[0009] Dissolve the halide AX and the halide BX2 in a non-polar solvent, and stir on a magnetic stirrer at room temperature until the mixed solution becomes colorless and transparent. A is at least one of an alkali metal element or an organic component, B is at least one of the fourth main group metal elements, and X is at least one of the halogen elements. In this step, AX and BX2 provide raw materials for subsequent solvent evaporation and solute crystallization to form ABX3.

[0010] Step 2: Add a ligand to the halide perovskite precursor solution prepared in step 1 to obtain a mixed solution, wherein the ligand is a surfactant. The volume concentration of the ligand in the mixed solution is 0.02%-2%, and the molar ratio of the halide to the ligand shall not be less than 80:1. In this step, the addition of the ligand is mainly used to change the surface energy of a specific crystal face of the perovskite crystal, thereby achieving anisotropic growth of the perovskite crystal.

[0011] Step 3: Drop the solution on the substrate and grow crystals at a temperature of 3°C-25°C in an anti-solvent vapor environment or an indoor air environment. The crystal growth time is 5 minutes to 48 hours. In this step, the anti-solvent vapor and the solvent in the mixed solution of step 2 merge with each other, reducing the solubility of the perovskite crystals, and the perovskite crystals precipitate.

[0012] Step 4: Take out the substrate, clean and dry it.

[0013] Furthermore, the alkali metal element in step 1 is Cs, Rb, Tl, etc., the organic component is methyl ether (FA), methylamino (MA), etc., the fourth main group metal element is Pb, Sn, Mn, etc., and the halogen element is Br, I, Cl, etc.

[0014] Furthermore, in step 1, the molar ratio of AX to BX2 is 1:0.9 to 0.9:1, the concentration of AX is 0.01M-0.1M, and the concentration of BX2 is 0.01M-0.1M.

[0015] Furthermore, the non-polar solvent in step 1 is one or a mixture of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO).

[0016] Furthermore, the surfactant in step 2 is a mixture of amines such as butylamine, hexylamine, oleylamine, etc. and oleic acid in equal proportions.

[0017] Further, the specific atmosphere in step three is one or more of isopropanol, ethanol, methanol, and sec-butanol. The reaction time is the time to remove the substrate from the anti-solvent atmosphere. Although perovskite crystals can be generated within a few minutes, if the reaction time is short, a large amount of solute will remain in the precursor solution. This will cause a large amount of solute to precipitate in the subsequent sample cleaning process. At this time, the generated perovskite crystals are irregular small particles, which will adhere to the substrate and the perovskite micro-nano array structure, affecting the further characterization of the sample and device preparation. Therefore, although the perovskite micro-nano array structure can be generated within a few minutes, in order to obtain a sample with a clean surface later, the reaction must be terminated after the solute in the perovskite precursor solution is completely precipitated and crystallized.

[0018] A halide perovskite micro-nano array structure is prepared by the above method to obtain a perovskite microwire or nanowire array structure composed of tens to hundreds of horizontally arranged perovskite microwires or nanowires, with a length of tens to hundreds of micrometers, a width of tens to tens of micrometers, and a thickness of tens to hundreds of nanometers.

[0019] The reaction principle of the present invention is: using anti-solvent assisted liquid phase crystallization method, the anti-solvent as a poor solvent for perovskite crystals is miscible with the perovskite precursor solution, which will increase the saturation of the perovskite precursor solution and promote the precipitation and crystallization of perovskite crystals. The reaction equation is: AX+BX2=ABX3.

[0020] Beneficial effects of the present invention:

[0021] (1) Under ambient conditions, halide perovskite micro-nano array structures can be prepared by a simple solution method without any pre-treatment. This avoids high temperature, pre-preparation of templates or chemical etching, electron beam etching, laser etching and other processes, and has the advantages of high efficiency, safety, low cost and simple operation.

[0022] (2) The size distribution of halide perovskite micro-nano arrays can be regulated by controlling the antisolvent atmosphere, temperature, precursor concentration and dosage. The size, spacing and other parameters of the perovskite micro-nano array structure can be further customized according to the needs of halide perovskite optoelectronic devices.

[0023] (3) The halide perovskite micro-nano arrays prepared by this method have excellent crystal quality, neat array arrangement, and high uniformity of micrometer lines. They have very good optical, electrical, and optoelectronic properties, laying a certain foundation for the application of halide perovskite materials in integrated devices.

[0024] (4) This method of preparing halide perovskite micro-nano array structures is not limited by the substrate and can be prepared on almost any substrate, including glass, silicon wafers, PET, PDMS, ITO, FTO and even plastic wrap. It can also be prepared in a container with a prepared precursor solution. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1(a) is an optical photograph of the halide perovskite micro-nano array structure obtained in Example 1 of the present invention and Figure 1(b) is an optical photograph of the halide perovskite micro-nano array structure on FTO obtained in Example 2 of the present invention. Figure 2(a) is a schematic diagram of the halide perovskite micro-nano array structure prepared in Example 1 of the present invention, where L represents length, W represents width, D represents spacing, and H represents thickness.

[0026] FIG. 2( b ) is a SEM image of the halide perovskite micro-nano array structure prepared in Example 1 of the present invention.

[0027] FIG3( a ) is a schematic diagram of the structure of the halide perovskite micro-nano array prepared in Example 2 of the present invention.

[0028] FIG3( b ) is an OM image of the halide perovskite micro-nano array structure prepared in Example 2 of the present invention.

[0029] Figure 4 (a)-(d) are OM images of halide perovskite micro-nano array structures prepared in an environment of 3℃-20℃; Figure 4 (a) is the product prepared in Example 2; Figure 4 (b) is the product prepared in Example 1; Figure 4 (c) is the product prepared in Example 3; Figure 4 (d) is the product prepared in Example 4.

[0030] FIG5(a) is a local SEM image of the CsPbBr3 micro-nano array structure obtained in Example 1, and FIG5(b) is a local enlarged image of FIG5(a).

[0031] FIG6( a ) is an AFM scanning image of the halide perovskite micro-nano array structure morphology obtained in Example 1.

[0032] FIG6( b ) is a height distribution diagram with arrow lines on the AFM scanning halide perovskite micro-nano array structure morphology image obtained in Example 1.

[0033] FIG. 7( a ) is an XRD spectrum of the halide perovskite micro-nano array structure obtained in Example 1.

[0034] FIG. 7( b ) is a photoluminescence spectrum of the halide perovskite micro-nano array structure obtained in Example 1.

[0035] Specific implementation method

[0036] The present invention is further described below in conjunction with implementation examples, but the scope of the present invention is not limited in any way. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, but cannot be construed as limiting the present invention. If specific techniques or conditions are not specified in the embodiments, the techniques or conditions described in the literature in this area or the product instructions are used. The reagents or instruments used that do not specify the manufacturer are all conventional products that can be obtained commercially. In order to make the purpose, technical solutions and advantages of the present invention clearer, the beneficial effects of the present invention will be further elaborated below through ten specific experimental schemes and three comparative examples:

[0037] Embodiment 1:

[0038] This embodiment provides a method for preparing a CsPbBr3 perovskite micro-nano array structure, and the specific steps are as follows:

[0039] Step 1: Prepare CsPbBr3 perovskite precursor solution

[0040] At room temperature, CsBr and PbBr2 with a molar ratio of 1:1 were dissolved in DMF, and the concentrations of CsBr and PbBr2 were both 0.05 M.

[0041] Step 2: Add oleic acid and oleylamine ligands in a volume ratio of 1:1 to the prepared CsPbBr3 perovskite precursor solution, and the volume concentration of oleic acid and oleylamine is 0.1%.

[0042] Step 3: Take 7 μl of the solution and drop it on the FTO substrate and place it in a reaction environment with isopropanol vapor at 9°C. As isopropanol and DMF dissolve each other, crystals precipitate. After 12 hours, take out the FTO substrate with the CsPbBr3 halide perovskite micro-nano array structure.

[0043] Step 4: Clean with isopropanol and then dry the CsPbBr3 halide perovskite micro-nano array structure.

[0044] The SEM image of the obtained product is shown in Figure 2(b), with a nanowire length (L) of 30-130μm, an average width (W) of 230nm, and a spacing (D) of 200nm-1μm. The surface morphology and thickness scans of the atomic force microscope are shown in Figures 6(a) and (b), with a thickness of about 250nm. The XRD is shown in Figure 7(a), from which it can be seen that the prepared sample has good crystallinity. The photoluminescence spectrum is shown in Figure 7(b), with a luminescence peak at 524nm, which is a typical CsPbBr3 luminescence.

[0045] Embodiment 2:

[0046] This embodiment provides a method for preparing a CsPbBr3 perovskite micro-nano array structure, and the specific steps are as follows:

[0047] Step 1: Prepare CsPbBr3 halide perovskite precursor solution. CsBr and PbBr2 with a molar ratio of 1:1 are dissolved in DMF. The concentrations of CsBr and PbBr2 are both 0.05M.

[0048] Step 2: Add oleic acid and oleylamine ligands in a volume ratio of 1:1 to the prepared CsPbBr3 halide perovskite precursor solution, and the volume concentration of oleic acid and oleylamine is 0.1%.

[0049] Step 3: Take 7 μl of the solution and place it in a reaction environment with isopropanol vapor at 20°C. As isopropanol and DMF dissolve each other, crystals precipitate. Take out the sample after 12 hours.

[0050] Step 4: Clean with isopropanol and then dry the CsPbBr3 halide perovskite micro-nano array structure.

[0051] The obtained product is Figure 4 As shown in (a), the nanowires have a length of 73-216 μm, a width of about 2 μm, and a spacing of about 3 μm.

[0052] Embodiment three:

[0053] This embodiment provides a method for preparing a CsPbBr3 perovskite micro-nano array structure, and the specific steps are as follows:

[0054] Step 1: Prepare CsPbBr3 perovskite precursor solution

[0055] At room temperature, CsBr and PbBr2 with a molar ratio of 1:1 were dissolved in DMF, and the concentrations of CsBr and PbBr2 were both 0.05 M.

[0056] Step 2: Add oleic acid and oleylamine ligands in a volume ratio of 1:1 to the prepared CsPbBr3 perovskite precursor solution, and the volume concentration of oleic acid and oleylamine is 0.1%.

[0057] Step 3: Take 7 μl of the solution and drop it on the FTO substrate and place it in a reaction environment with isopropanol vapor at 6°C. As isopropanol and DMF dissolve each other, crystals precipitate. After 12 hours, take out the FTO substrate with the CsPbBr3 halide perovskite micro-nano array structure.

[0058] Step 4: Clean with isopropanol and then dry the CsPbBr3 halide perovskite micro-nano array structure.

[0059] The obtained product is Figure 4 As shown in (c), compared with Example 2, the length of the nanowires is longer and the number of nanowires is less.

[0060] Embodiment 4:

[0061] This embodiment provides a method for preparing a CsPbBr3 perovskite micro-nano array structure, and the specific steps are as follows:

[0062] Step 1: Prepare CsPbBr3 perovskite precursor solution

[0063] At room temperature, CsBr and PbBr2 with a molar ratio of 1:1 were dissolved in DMF, and the concentrations of CsBr and PbBr2 were both 0.05 M.

[0064] Step 2: Add oleic acid and oleylamine ligands in a volume ratio of 1:1 to the prepared CsPbBr3 perovskite precursor solution, and the volume concentration of oleic acid and oleylamine is 0.1%.

[0065] Step 3: Take 7 μl of the solution and drop it on the FTO substrate and place it in a reaction environment with isopropanol vapor at 3°C. As isopropanol and DMF dissolve each other, crystals precipitate. After 12 hours, take out the FTO substrate with the CsPbBr3 halide perovskite micro-nano array structure.

[0066] Step 4: Clean with isopropanol and then dry the CsPbBr3 halide perovskite micro-nano array structure.

[0067] The obtained product is Figure 4 As shown in (c), the length of the nanowires is shorter and the number of nanowires is less than that of Example 3. This may be because the crystal precipitation is slower in a low temperature environment, and the crystals obtained in the same time are smaller.

[0068] Embodiment five:

[0069] This embodiment provides a method for preparing a CsPbBr3 perovskite micro-nano array structure, and the specific steps are as follows:

[0070] Step 1: Prepare CsPbBr3 halide perovskite precursor solution. CsBr and PbBr2 with a molar ratio of 1:1 are dissolved in DMF. The concentrations of CsBr and PbBr2 are both 0.025M.

[0071] Step 2: Add oleic acid and oleylamine ligands in a volume ratio of 1:1 to the prepared CsPbBr3 halide perovskite precursor solution, and the volume concentration of oleic acid and oleylamine is 0.05%.

[0072] Step 3: Take 7 μl of the solution and place it on a FTO substrate in a reaction environment with isopropanol vapor at 6°C. As isopropanol and DMF dissolve each other, crystals precipitate. Take out the sample after 12 hours.

[0073] Step 4: Clean with isopropanol and then dry the CsPbBr3 halide perovskite micro-nano array structure.

[0074] The morphology of the obtained product is basically consistent with that of Example 3, and the distribution of the single crystal perovskite nanowire array is more dispersed, which is convenient for transferring the material using the micro-nano material transfer operation platform and for further preparing optoelectronic devices.

[0075] Embodiment six:

[0076] This embodiment provides a method for preparing a CsPbBr3 perovskite micro-nano array structure, and the specific steps are as follows:

[0077] Step 1: Prepare CsPbBr3 halide perovskite precursor solution. CsBr and PbBr2 with a molar ratio of 1:1 are dissolved in DMF. The concentrations of CsBr and PbBr2 are both 0.01M.

[0078] Step 2: Add oleic acid and oleylamine ligands in a volume ratio of 1:1 to the prepared CsPbBr3 halide perovskite precursor solution, and the volume concentration of oleic acid and oleylamine is 0.02%.

[0079] Step 3: Take 7 μl of the solution and place it on a FTO substrate in a reaction environment with isopropanol vapor at 9°C. As isopropanol and DMF dissolve each other, crystals precipitate. Take out the sample after 5 minutes.

[0080] Step 4: Clean with isopropanol and then dry the CsPbBr3 halide perovskite micro-nano array structure.

[0081] The single crystal perovskite nanowire array nanowire length of the obtained product is only about 10 microns, the number of nanowires is small, and the nanowire arrangement is relatively sparse.

[0082] Embodiment seven:

[0083] This embodiment provides a method for preparing a CsPbBr3 perovskite micro-nano array structure, and the specific steps are as follows:

[0084] Step 1: Prepare CsPbBr3 halide perovskite precursor solution. CsBr and PbBr2 with a molar ratio of 1:1 are dissolved in DMF. The concentrations of CsBr and PbBr2 are both 0.05M.

[0085] Step 2: Add oleic acid and oleylamine ligands in a volume ratio of 1:1 to the prepared CsPbBr3 halide perovskite precursor solution, and the volume concentration of oleic acid and oleylamine is 0.1%.

[0086] Step 3: Take 7 μl of the solution and place it on the FTO substrate in an air, 25°C reaction environment. As isopropanol and DMF dissolve each other, crystals precipitate. Take out the sample after 24 hours.

[0087] Step 4: Clean with isopropanol and then dry the CsPbBr3 halide perovskite micro-nano array structure.

[0088] The morphology of the resulting nanowire array is smaller, shorter, wider, and wider than that of the nanowires grown under antisolvent vapor conditions. Moreover, due to the coffee ring effect, the grown material is stacked into a ring on the substrate, which makes it impossible to achieve lossless dispersion and is not convenient for further processing using a micro-nano material transfer operating system.

[0089] Embodiment 8

[0090] This embodiment provides a method for preparing a CsPbBr3 perovskite micro-nano array structure, and the specific steps are as follows:

[0091] Step 1: Prepare CsPbBr3 halide perovskite precursor solution. CsBr and PbBr2 with a molar ratio of 1:1 are dissolved in DMSO. The concentrations of CsBr and PbBr2 are both 0.05M.

[0092] Step 2: Add oleic acid and oleylamine ligands in a volume ratio of 1:1 to the prepared CsPbBr3 halide perovskite precursor solution, and the volume concentration of oleic acid and oleylamine is 1%.

[0093] Step 3: Take 100 μl of the solution and place it in a reaction environment at 25° C. in a methanol:ethanol vapor environment with a volume ratio of 1:2. As the antisolvent and DMSO dissolve in each other, crystals precipitate. Take out the sample after 24 hours.

[0094] Step 4: Clean with ethanol and then dry the CsPbBr3 halide perovskite micro-nano array structure.

[0095] Since more precursor solution is used than in Example 1, the obtained nanowires are longer, and the width, thickness and spacing are similar to those in Example 2.

[0096] Embodiment 9

[0097] This embodiment provides a method for preparing a CsPbBr3 perovskite micro-nano array structure, and the specific steps are as follows:

[0098] Step 1: Prepare CsPbBr3 halide perovskite precursor solution. CsBr and PbBr2 with a molar ratio of 1:1 are dissolved in DMSO. The concentrations of CsBr and PbBr2 are both 0.1M.

[0099] Step 2: Add oleic acid and oleylamine ligands in a volume ratio of 1:1 to the prepared CsPbBr3 halide perovskite precursor solution, and the volume concentration of oleic acid and oleylamine is 2%.

[0100] Step 3: Place 1 ml of the solution in an ethanol vapor environment at 15°C. As the antisolvent and DMSO dissolve in each other, crystals precipitate. Take out the sample after 48 hours.

[0101] Step 4: Clean with ethanol and then dry the CsPbBr3 halide perovskite micro-nano array structure.

[0102] The obtained product contains CsPbBr3 perovskite micro-nano array structures, but the number of CsPbBr3 perovskite micro-nano array structures is small. The size distribution of CsPbBr3 perovskite micro-nano array structures is similar to that of Example 2.

[0103] Embodiment 10

[0104] The CsPbBr3 halide perovskite micro-nano array structure obtained in Example 1 can be ion exchanged to obtain perovskite micro-nano arrays of other components.

[0105] Step 1: Prepare ion exchange solution

[0106] Take 30 mg of PbI2, 200 μl of oleic acid and 200 μl of oleylamine and dissolve them in 5 ml of octadecene. Stir in a 100°C water bath until they are completely dissolved to obtain a light yellow transparent solution.

[0107] Step 2: Ion exchange reaction

[0108] The FTO with CsPbBr3 halide perovskite micro-nano array structure was placed in a vial containing the solution of step 1 and allowed to stand at room temperature for 17 hours.

[0109] You can get CsPbI x Br 3-x The halide perovskite micro-nano array structure, the obtained sample structure is well preserved, the photoluminescence is red, and the emission peak is around 690nm.

[0110] Comparative Example 1 (Compared with Example 1 of the present invention)

[0111] Step 1: Prepare CsPbBr3 halide perovskite precursor solution. CsBr and PbBr2 with a molar ratio of 1:1 are dissolved in DMF. The concentrations of CsBr and PbBr2 are both 0.05M.

[0112] Step 2: Add oleic acid and oleylamine ligands in a volume ratio of 1:1 to the prepared CsPbBr3 halide perovskite precursor solution, and the volume concentration of oleic acid and oleylamine is 0.05%.

[0113] Step 3: Place the solution in a reaction environment with isopropanol vapor at 9°C. As isopropanol and DMF dissolve in each other, crystals precipitate. Take out the sample after 12 hours.

[0114] Step 4: Wash with isopropanol and then dry the CsPbBr3 halide perovskite. The resulting product is a random small crystal, and the halide perovskite micro-nano array structure cannot be obtained. This is because the molar ratio of halide to ligand is less than 80:1, resulting in the ligand being unable to modify the crystal surface to achieve anisotropic growth of the crystal.

[0115] Comparative Example 2 (Compared with Example 2 of the present invention)

[0116] Step 1: Prepare CsPbBr3 halide perovskite precursor solution. CsBr and PbBr2 with a molar ratio of 1:1 are dissolved in DMF. The concentrations of CsBr and PbBr2 are both 0.05M.

[0117] Step 2: Add oleic acid and oleylamine ligands in a volume ratio of 1:1 to the prepared CsPbBr3 halide perovskite precursor solution, and the volume concentration of oleic acid and oleylamine is 0.1%.

[0118] Step 3: Place the solution in a reaction environment with methanol vapor at 20°C. As methanol and DMF dissolve in each other, crystals precipitate. Take out the sample after 12 hours.

[0119] Step 4: Wash with methanol and then dry the CsPbBr3 halide perovskite.

[0120] The obtained product is random small crystals, and the halide perovskite micro-nano array structure cannot be obtained. This may be because methanol has a stronger polarity than isopropanol. Therefore, when methanol is used alone as an anti-solvent, the stronger polarity affects the anisotropic growth of the perovskite crystals.

[0121] Comparative Example 3 (Compared with Example 3 of the present invention)

[0122] Step 1: Prepare CsPbBr3 halide perovskite precursor solution. CsBr and PbBr2 with a molar ratio of 1:1 are dissolved in DMF. The concentrations of CsBr and PbBr2 are both 0.05M.

[0123] Step 2: Add only oleylamine ligand to the prepared CsPbBr3 halide perovskite precursor solution, and the volume concentration of oleylamine is 0.1%.

[0124] Step 3: Place the solution in a reaction environment with isopropanol vapor at 6°C. As isopropanol and DMF dissolve in each other, crystals precipitate. Take out the sample after 12 hours.

[0125] Step 4: Clean and dry the CsPbBr3 halide perovskite with isopropyl alcohol.

[0126] The obtained product is random small crystals. In this comparative example, the perovskite precursor solution lacks oleic acid, so the halide perovskite micro-nano array structure cannot be obtained, indicating that the joint action of oleic acid and oleylamine is required to modify the perovskite crystal surface and realize the anisotropic growth of the perovskite crystal.

[0127] The above-mentioned embodiments only express the implementation methods and features of the present invention but cannot be understood as limiting the patent of the present invention. It should be pointed out that for those skilled in the art, without departing from the concept of the present invention, the technology that can be obtained through logical analysis, reasoning or limited experiments can also be modified and improved, which all belong to the protection scope of the present invention.

Claims

1. A method for preparing a halide perovskite micro-nano array structure, characterized in that: The liquid-phase reverse solvent-assisted crystallization method comprises the following steps: Step 1: Prepare ABX3 perovskite precursor solution At room temperature, the halide AX and the halide BX2 are dissolved in a non-polar solvent, and stirred until colorless and transparent to obtain a mixed solution; wherein A is at least one of an alkali metal element or an organic component, B is at least one of a fourth main group metal element, and X is at least one of a halogen element; Step 2: Add a surfactant as a ligand to the halide perovskite precursor solution prepared in step 1, and mix them evenly to obtain a mixed solution; wherein the ligand is used to achieve anisotropic growth of perovskite crystals; the volume concentration of the ligand in the mixed solution is 0.02%-2%, and the molar ratio of the halide to the ligand shall not be less than 80:1; the surfactant is formed by mixing amines and oleic acid in equal proportions, wherein the amines include butylamine, hexylamine, and oleylamine; Step 3: Dropping the mixed solution on the substrate, and growing crystals at a temperature of 3°C-25°C in an anti-solvent vapor environment or an indoor air environment; wherein the crystal growth time is 5 minutes to 48 hours; wherein the anti-solvent in the anti-solvent vapor environment includes one or more of isopropanol, ethanol, methanol, and sec-butanol; Step 4: Take out the substrate, clean and dry it.

2. The method for preparing a halide perovskite micro-nano array structure according to claim 1, characterized in that: In step 1, the alkali metal elements are Cs, Rb, and Tl, the organic components are methyl ether FA, methylamino MA, etc., the fourth main group metal elements are Pb, Sn, and Mn, and the halogen elements are Br, I, and Cl.

3. The method for preparing a halide perovskite micro-nano array structure according to claim 1, characterized in that: In step 1, the molar ratio of AX to BX2 is 1:0.9 to 0.9:1, the concentration of AX is 0.01M-0.1M, and the concentration of BX2 is 0.01M-0.1M.

4. The method for preparing a halide perovskite micro-nano array structure according to claim 1, characterized in that: The non-polar solvent in step 1 is one of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) or a mixture of the two solvents.

5. A halide perovskite micro-nano array structure, characterized in that: The preparation method according to any one of claims 1 to 4 is used to obtain a perovskite microwire or nanowire array structure consisting of tens to hundreds of horizontally arranged perovskite microwires or nanowires, with a length of tens to hundreds of micrometers, a width of tens to tens of micrometers, and a thickness of tens to hundreds of nanometers.

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