Method for gradient-constant temperature growth of perovskite single crystal film on heterogeneous wetting substrate
Through heteromoisturizing substrates and gradient-constant temperature growth method, the nucleation and growth competition problems in the preparation of perovskite single crystal thin films are solved, and efficient and low-defect perovskite single crystal thin film preparation is achieved, providing key technical support for the industrialization of optoelectronic devices.
Patent Information
- Application Number
- CN202510541413.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-27
- Publication Date
- 2025-07-18
AI Technical Summary
In the preparation of perovskite single crystal thin films, the prior art has long growth cycle, complex equipment, high operation difficulty, and many grain boundary defects caused by competition in nucleation and growth, making it difficult to achieve efficient and stable industrial production.
The heterowetted substrate combined with gradient-constant temperature growth method is used to regulate the solvent volatility rate and solute diffusion direction through the surface energy difference between the hydrophobic substrate and the microhydrophobic substrate. After the gradient is warmed up, the perovskite single crystal thin film is grown in a constant temperature environment to avoid oversaturation, separate the nucleation and growth stages, and control the crystal quality.
It realizes short-term and efficient preparation of perovskite single crystal thin film, controllable thickness, high crystal quality and few defects, and is suitable for industrial applications of optoelectronic devices, simplifying the operating process and reducing costs.
Smart Images
Figure CN120330863A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of crystal growth, and in particular relates to a method for preparing a perovskite single crystal film. Background Art
[0002] Metal halide perovskite materials have high light absorption coefficients, and a perovskite layer of a few hundred nanometers can effectively absorb sunlight; the absorption spectrum range is adjustable, and the band gap can be adjusted by changing the composition of the perovskite, so that it can absorb light of different wavelengths; the carrier transport performance is good (longer carrier diffusion length, higher carrier mobility), which enables it to quickly transport charges in optoelectronic devices and improve the response speed and performance of the device; it can be processed by solution methods (such as spin coating, scraping, inkjet printing, etc.), and compared with the complex processes such as high temperature and high vacuum of traditional optoelectronic devices, it has low cost and is suitable for large-scale production. Therefore, it has shown great potential in the fields of solar cells, light-emitting diodes and photodetectors. Compared with perovskite polycrystalline films, perovskite single crystal films have higher crystal quality, no grain boundary interference, lower defect state density, higher carrier mobility and diffusion length, and better environmental stability, so they have received special attention.
[0003] Many advances have been made in the spatial confinement method for growing perovskite single crystal films. Based on this method, researchers have also used slow growth at room temperature or programmed temperature control equipment to accurately control the film growth rate, introduce seed crystal growth, repeatedly replenish liquid during the growth process, and control the liquid level to prepare high-quality single crystal films. Although these strategies have optimized some processes, they still have significant defects. The room temperature or programmed temperature growth cycle is long. The preparation of seed crystals requires an additional transfer process, which greatly increases the complexity and is prone to contamination and defects. Repeated replenishment during film growth can easily introduce bubbles or impurities, destroying the continuity of the film, and the amount and timing of replenishment are difficult to accurately control. Fluctuations in solution concentration can easily induce secondary nucleation, forming competitive growth of microcrystals. The liquid level adjustment depends on the dynamic changes in the evaporation rate, which leads to unstable supersaturation, ultimately affecting the uniformity of the film.
[0004] The above methods all require multi-step intervention or complex equipment and operation support, and the process tolerance is low, making it difficult to achieve efficient and stable industrial production. Therefore, improving the success rate of large-size and thickness-controllable perovskite single crystal thin films based on the spatial confinement method is a technical problem that needs to be solved urgently. Summary of the invention
[0005] The present invention provides a method for preparing a perovskite single crystal film with controllable size and thickness by using a combination of a hydrophobic substrate and a micro-hydrophobic substrate based on the spatial confinement method, regulating the solvent evaporation rate and the solute diffusion direction by utilizing the surface tension difference of heterogeneous wetting, first performing gradient heating for pre-nucleation, and then performing isothermal growth. During the preparation of the single crystal film, the surface energy difference between the hydrophobic substrate and the normally cleaned micro-hydrophobic substrate forms a directional solvent evaporation gradient, reducing the nucleation density of the single crystal film and accelerating the growth rate. At the same time, the growth of the single crystal film is anchored on the micro-hydrophobic side, avoiding the fracture of the single crystal film and facilitating peeling, providing an idea for the preparation of optoelectronic devices. The growth process adopts gradient heating to focus on nucleation control, avoiding the supersaturation overshoot in the traditional high-temperature one-step method, thereby suppressing explosive nucleation. The isothermal stage focuses on crystal expansion, and the separation of nucleation and growth avoids the grain boundary defects caused by the competition between nucleation and growth in the traditional process. This method has the characteristics of simple operation process, low cost, high process tolerance, short time and high efficiency, controllable thickness and area, etc., making up for the deficiencies of the existing technology.
[0006] To solve the above technical problems, the present invention proposes the following technical solutions.
[0007] In a first aspect, the present invention provides a method for growing a perovskite single crystal film with a gradient-constant temperature on a heterogeneous wetting substrate, the method comprising the following steps:
[0008] (1) Dissolve the metal halide perovskite raw materials AX and BX2 in a solvent in a certain proportion, and stir to dissolve to prepare a precursor solution;
[0009] (2) Filter the perovskite precursor solution to obtain a clear and transparent solution;
[0010] (3) Ultrasonically clean two substrates successively with dishwashing liquid, glass water, deionized water, and ethanol for 10 minutes, and then place them in an oven to dry for later use;
[0011] (4) Treat one of the substrates with a hydrophobic solution for hydrophobic treatment;
[0012] (5) Drop the perovskite precursor solution onto a normally cleaned micro-hydrophobic substrate, cover the other hydrophobic-treated substrate, and perform gradient heating for pre-nucleation;
[0013] (6) Subsequently, continue to grow the sample that has completed pre-nucleation in an isothermal environment, and control the growth thickness of the single crystal film by changing the pressure between the two substrates; finally, a perovskite single crystal film grows between the two substrates.
[0014] Wherein, A is one or more mixtures of MA + , FA + , Cs + , and B is Pb 2+ , Sn 2+ , Mn2+ One or more of them, X is Cl - , Br - , I - One or more of them.
[0015] Furthermore, the molar ratio of AX to BX2 is 1:1, and the concentration of the precursor in the precursor solution is 0.5 - 1.5 M.
[0016] Furthermore, the solvent is one or several of N,N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, hydrobromic acid, and hydroiodic acid mixed in any proportion. Preferred: N,N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone.
[0017] Furthermore, the substrate is conductive glass, soda-lime glass, silicon wafer, gallium arsenide, or polytetrafluoroethylene film; the side length dimension of the substrate is 2 - 10 cm.
[0018] Furthermore, the hydrophobic solution is one or several of perfluorodecyltriethoxysilane, octadecyltrichlorosilane, perfluorooctyltriethoxysilane, and polydimethylsiloxane mixed with ethanol and deionized water in any proportion. Specifically: Place the cleaned substrate in the prepared hydrophobic solution and soak for 0 - 1 h, then take it out and dry at 60 - 90 °C, and the drying is carried out through a heating table or an oven.
[0019] Furthermore, the amount of the precursor solution dropped is 2 - 20 μL. Preferred: 10 μL.
[0020] Furthermore, the gradient temperature increase is specifically: First, set the temperature to 35 - 65 °C, and increase the temperature by 5 °C per hour to 65 - 95 °C. The heating is carried out through a heating table, an oven, a water bath, an oil bath, or other foreseeable heating methods.
[0021] Furthermore, the constant temperature environment is specifically: Set the temperature to 40 - 70 °C and maintain for 10 - 24 h. The heating is carried out through a heating table, an oven, a water bath, an oil bath, or other foreseeable heating methods.
[0022] Furthermore, according to the thickness of the desired product, change the way of applying force to the substrate, including applying weights, spring clips, springs, magnets, screw fastening, or other foreseeable force application methods on the substrate; according to the thickness of the desired product, select polydimethylsiloxane or polytetrafluoroethylene films with different thicknesses to combine two substrates to obtain a confined space with a certain thickness.
[0023] In the second aspect, the present invention provides a perovskite single crystal thin film prepared by the above method.
[0024] The present invention has the following beneficial effects:
[0025] (1) The method for preparing perovskite single crystal thin films provided by the present invention can achieve single crystal thin films with controllable size and thickness in a short time and with high efficiency compared with traditional methods.
[0026] (2) The substrate based on heterogeneous wetting provided by the present invention, through the synergistic effect of surface energy gradient and solute directional migration, suppresses stray nucleation, improves crystal quality and efficiency, and realizes low-defect and high-speed growth compared with traditional methods; and efficient peeling provides a non-destructive transfer solution for device preparation, promoting the industrial application of perovskite optoelectronic devices.
[0027] (3) The gradient-constant temperature growth perovskite single crystal thin film provided by the present invention focuses on nucleation control during gradient heating, avoiding the supersaturation overshoot in the traditional high-temperature one-step method, thereby suppressing explosive nucleation. The constant temperature stage focuses on crystal expansion, and the separation of nucleation and growth avoids the grain boundary defects caused by the competition between nucleation and growth in traditional processes. Through the synergistic effect of staged temperature control and substrate surface energy regulation, the core problems of uncontrollable nucleation and many growth defects in the preparation of perovskite single crystal thin films are solved, with both high efficiency and high quality, providing a key technical path for the industrialization of optoelectronic devices. Description of the Drawings
[0028] To provide a further understanding of the present invention, the drawings required for use in the description of the embodiments or the prior art will be briefly introduced below, which shall not unduly limit the present invention.
[0029] Figure 1 It is the MAPbBr3 single crystal thin film prepared in Example 1 of the present invention;
[0030] Figure 2 It is the cross-sectional view of MAPbBr3 single crystal thin films with different thicknesses obtained by changing the pressure applied to the substrate in Example 1 of the present invention:
[0031] Figure 3 It is the optical microscope photograph of the MAPbBr3 single crystal thin film in Example 1 of the present invention;
[0032] Figure 4 It is the XRD pattern of the MAPbBr3 single crystal thin film in Example 1 of the present invention;
[0033] Figure 5 It is the MAPbBr3 single crystal thin film obtained by the method of growing single crystal films without using a substrate based on heterogeneous wetting in Comparative Example 1 of the present invention;
[0034] Figure 6 It is the MAPbBr3 single crystal thin film obtained by the method of growing single crystal films without using the gradient-constant temperature growth method in Comparative Example 2 of the present invention. Detailed Embodiments
[0035] It should be noted that the following detailed description is exemplary and is intended to provide further illustration of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.
[0036] To make the substantial features and the practicality of the present invention more easily understood, the technical solutions of the present invention will be further described in detail below in conjunction with the accompanying drawings and several specific embodiments. However, the following description and illustration of the embodiments do not constitute any limitation to the protection scope of the present invention. Any equivalent transformation or substitution in function, method, or structure made by those of ordinary skill in the art according to these embodiments shall fall within the protection scope of the present invention.
[0037] Example 1
[0038] Experimental steps for obtaining MAPbBr3 single crystal thin films:
[0039] Dissolve lead bromide and methylammonium bromide in N,N-dimethylformamide (DME), stir and dissolve in a medicine bottle, and filter with a 0.22-μm filter head to obtain a clear and transparent MAPbBr3 precursor solution. The molar ratio of lead bromide to methylammonium bromide is 1:1, and the concentration of Pb 2+ is 1.5 M;
[0040] Select two square conductive glass sheets with a side length of 50 mm and a thickness of 1 mm as substrates;
[0041] Ultrasonically clean the two selected substrates with dishwashing liquid, glass water, deionized water, and ethanol for 10 minutes each and then dry them;
[0042] Treat one of the substrates with a hydrophobic solution diluted with perfluorodecyltriethoxysilane mixed with deionized water and ethanol for hydrophobic treatment;
[0043] Drop 10 μL of the perovskite precursor solution onto a normally cleaned and slightly hydrophobic substrate, cover it with another hydrophobic-treated substrate, control the growth thickness of the single crystal thin film by changing the pressure between the two substrates, and then place it on a hot plate at 50 °C and raise the temperature by 5 °C per hour to 80 °C for gradient heating to obtain millimeter-sized small crystal nuclei;
[0044] Continue to place the sample after pre-nucleation in an oven at 60 °C for constant temperature growth, and finally grow a perovskite single crystal thin film with the required thickness and larger area between the two substrates.
[0045] Figure 1 This is a photo of the MAPbBr3 single crystal thin film in Embodiment 1 of the present invention. The length of each square in the figure is 1 mm. From Figure 1 it can be seen that the single crystal thin film is large-sized and regular in shape.
[0046] As can be seen from Figure 2 Figure 1, cross-sectional views of MAPbBr3 single-crystal thin films with different thicknesses obtained in Example 1 of the present invention are shown.
[0047] As can be seen from Figure 3 Figure 2, the surface of the MAPbBr3 single-crystal thin film obtained in Example 1 of the present invention is smooth and flat without macroscopic grain boundaries.
[0048] As can be seen from Figure 4 Figure 3, the crystallinity of the MAPbBr3 single-crystal thin film in the technical solution of the present invention is good, and crystal planes (100), (200), (300), and (400) are detected on the surface of the single-crystal thin film, all belonging to the {100} crystal plane family.
[0049] Comparative Example 1
[0050] Lead bromide and methylammonium bromide in equimolar amounts are dissolved in N,N-dimethylformamide (DMF), stirred and dissolved in a vial, and filtered until a clear and transparent MAPbBr3 precursor solution is obtained. The concentration of the precursor solution is 1.5 M.
[0051] Two square conductive glass sheets with a side length of 50 mm and a thickness of 1 mm are selected as substrates.
[0052] The two selected substrates are ultrasonically treated with dishwashing liquid, glass cleaner, deionized water, and ethanol for 10 min each and then dried.
[0053] 10 μL of the perovskite precursor solution is dropped onto one substrate, and the other substrate is covered. The growth thickness of the single-crystal thin film is controlled by changing the pressure between the two substrates. Subsequently, it is placed on a hot stage at 50 °C and heated to 80 °C at a rate of 5 °C per hour for gradient heating to obtain small crystal nuclei.
[0054] The sample that has completed pre-nucleation is continuously placed in an oven at 60 °C for constant-temperature growth, and finally, a perovskite single-crystal thin film with the required thickness and a large area is grown between the two substrates.
[0055] Figure 5 This is a photograph of the MAPbBr3 single-crystal thin film grown on a 50-mm square substrate in Comparative Example 1 of the present invention. As can be seen from Figure 5 Figure 4, without using the asymmetric hydrophobic treatment method, polycrystals are likely to form in a large area, and it is difficult to form a large-size single-crystal thin film.
[0056] Comparative Example 2
[0057] Lead bromide and methylammonium bromide are dissolved in N,N-dimethylformamide (DMF), stirred and dissolved in a medicine bottle, and filtered through a 0.22-μm filter head to obtain a clear and transparent MAPbBr3 precursor solution. The molar ratio of lead bromide to methylammonium bromide is 1:1, Pb2+ The concentration is 1.5 M;
[0058] Select two square conductive glass sheets with a side length of 50 mm and a thickness of 1 mm as the substrates;
[0059] Ultrasonically clean the two selected substrates with dishwashing liquid, glass water, deionized water, and ethanol for 10 minutes each and then dry them;
[0060] Hydrophobically treat one of the substrates with a hydrophobic solution diluted with perfluorodecyltriethoxysilane;
[0061] Drop 10 μL of the perovskite precursor solution onto one of the normally cleaned and slightly hydrophobic substrates, cover it with the other hydrophobically treated substrate, control the growth thickness of the single-crystal thin film by changing the pressure between the two substrates, and then place it on a hot plate at 60 °C for isothermal growth.
[0062] Figure 6 This is a photograph of the MAPbBr3 single-crystal thin film in Comparative Example 2 of the present invention. The length of each square in the figure is 1 mm. From Figure 6 It can be seen that it is very difficult to form a large-sized and regularly shaped single-crystal thin film without using the gradient-isothermal method.
[0063] Example 2
[0064] Experimental steps for obtaining the MAPbCl3 single-crystal thin film:
[0065] Dissolve lead chloride and methylammonium chloride in a mixed solution of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO), stir and dissolve in a medicine bottle, and filter with a 0.22-μm filter head to obtain a clear and transparent MAPbCl3 precursor solution. The molar ratio of lead chloride to methylammonium chloride is 1:1, and the concentration of Pb 2+ The concentration is 1 M;
[0066] Select two square glass sheets with a side length of 50 mm and a thickness of 1 mm as the substrates;
[0067] Ultrasonically clean the two selected glass substrates with dishwashing liquid, glass water, deionized water, and ethanol for 10 minutes each and then dry them;
[0068] Hydrophobically treat one of the substrates with a hydrophobic solution diluted with perfluorodecyltriethoxysilane;
[0069] Drop 10 μL of the perovskite precursor solution onto one of the normally cleaned and slightly hydrophobic substrates, cover it with the other hydrophobically treated substrate, control the growth thickness of the single-crystal thin film by changing the pressure between the two substrates, and then place it on a hot plate at 50 °C and increase the temperature by 5 °C per hour to 80 °C for gradient heating to obtain small crystal nuclei;
[0070] Continue to place the sample that has completed pre-nucleation in an oven at 60°C for constant-temperature growth, and a perovskite single-crystal thin film with a required thickness and a large area can be grown between the two substrates.
[0071] The above is only the preferred implementation mode of the present invention. The protection scope of the present invention is not limited to the above embodiments. All technical solutions within the idea of the present invention belong to the protection scope of the present invention. It should be noted that for those of ordinary skill in the art, several improvements and refinements made without departing from the principle of the present invention should be regarded as within the protection scope of the present invention.
Claims
1. A method for preparing a perovskite single crystal thin film, characterized in that, It includes the following steps: (1) Dissolve metal halide perovskite raw materials AX and BX2 in a solvent in a certain proportion, and stir to dissolve to prepare a precursor solution; (2) Filter the perovskite precursor solution to obtain a clear and transparent solution; (3) Ultrasonically clean two substrates successively with dishwashing liquid, glass water, deionized water, and ethanol for 10 minutes, and then place them in an oven to dry for standby; (4) Hydrophobically treat one of the substrates with a hydrophobic solution; (5) Drop the perovskite precursor solution onto a normally cleaned and slightly hydrophobic substrate, cover the other hydrophobically treated substrate, and perform gradient temperature rise for pre-nucleation; (6) Subsequently, continue to grow the sample that has completed pre-nucleation in a constant temperature environment, and control the growth thickness of the single crystal thin film by changing the pressure between the two substrates; finally, grow a perovskite single crystal thin film between the two substrates; Among them, A is one or more mixtures of MA + , FA + , Cs + , B is one or more of Pb 2+ , Sn 2+ , Mn 2+ , and X is one or more of Cl - , Br - , I - .
2. The preparation method according to claim 1, characterized in that, The molar ratio of AX to BX2 is 1:1, and the concentration of the precursor in the precursor solution is 0.5 - 1.5M.
3. The preparation method according to claim 1, characterized in that, The solvent is one or several of N,N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, hydrobromic acid, and hydroiodic acid in any proportion.
4. The preparation method according to claim 11, characterized in that, The substrate is conductive glass, soda-lime glass, silicon wafer, gallium arsenide, or polytetrafluoroethylene film; the side length dimension of the substrate is 2 - 10 cm.
5. The preparation method according to claim 1, characterized in that The hydrophobic solution is one or several of perfluorodecyltriethoxysilane, octadecyltrichlorosilane, perfluorooctyltriethoxysilane, and polydimethylsiloxane mixed with ethanol and deionized water in any proportion. Specifically: Immerse the cleaned substrate in the prepared hydrophobic solution for 0 - 1 h, take it out and dry it at 60 - 90 °C, and the drying is carried out by a heating table or an oven.
6. The preparation method according to claim 1, wherein The amount of the dropped precursor solution is 2 - 20 uL.
7. The preparation method according to claim 1, characterized in that, The gradient temperature rise is specifically: First, set the temperature to 35 - 65 °C, raise the temperature by 5 °C per hour to 65 - 95 °C, and the heating is carried out by a heating table, an oven, a water bath, or an oil bath.
8. The preparation method according to claim 1, characterized in that, The constant temperature environment is specifically: Set the temperature to 40 - 70 °C, keep it for 10 - 24 h, and the heating is carried out by a heating table, an oven, a water bath, or an oil bath.
9. The preparation method according to claim 1, characterized in that, Change the way of applying force to the substrate according to the required product thickness, including applying weights, spring clips, springs, magnets, or screw fasteners on the substrate; according to the required product thickness, select polydimethylsiloxane or polytetrafluoroethylene films with different thicknesses to combine the two substrates to obtain a confined space with a certain thickness.
10. A perovskite single crystal thin film with controllable size and thickness prepared by the preparation method according to any one of claims 1 - 9.