Method for preparing quasi-two-dimensional perovskite thin film through stripping and application of quasi-two-dimensional perovskite thin film

Abstract

The invention discloses a method for preparing a quasi-two-dimensional perovskite film by stripping and application thereof. The method comprises the following steps: A1, spin-coating a perovskite precursor on the surface of a substrate to obtain a substrate coated with a film; a2, an adhesive tape is attached to the substrate coated with the thin film, and the adhesive tape is peeled off after annealing. According to the preparation method of the quasi-two-dimensional perovskite thin film, a surface defect layer is effectively removed, the recrystallization process of quasi-two-dimensional perovskite crystals is further promoted, the charge trap density is remarkably reduced, the charge transmission efficiency is enhanced, and then the photoluminescence quantum yield (PLQY) of the stripped quasi-two-dimensional perovskite thin film is greatly improved.

Description

Technical Field

[0001] The invention belongs to the technical field of microelectronic devices, and in particular relates to a method for preparing a quasi-two-dimensional perovskite film by exfoliation and an application thereof. Background Art

[0002] Quasi-two-dimensional perovskite, as a new type of optoelectronic material that combines the properties of two-dimensional materials and perovskite materials, has unique characteristics and significant advantages, including high fluorescence quantum yield (PLQY), easily adjustable band gap, narrow emission peak, good material stability, low cost of preparation and easy availability of material sources, etc., which has attracted the attention of widespread researchers.

[0003] The universal chemistry of quasi-two-dimensional perovskite materials is (RNH3)2A n-1 B n X 3n+1 , where R represents an organic long-chain molecule or a functional group, such as phenethylamine (C6H5-CH2CH2-NH3 + , referred to as PEA + ) and butylamine (C4H9-NH3 + , referred to as BA + ) and so on. These organic cations act as spacers in the perovskite structure to form a layered structure. NH3 is combined with R to form organic ammonium cations, also known as organic ligand materials. These cations play a role in balancing charges and stabilizing structures in the perovskite lattice. A represents short-chain organic cations, such as methylamine (MA) or ethylamine (FA). These short-chain cations usually interact with anions in the inorganic layer, affecting the photoelectric properties of the perovskite. B: represents divalent metal cations, such as lead (Pb) or tin (Sn). These metal cations form an octahedral structure with halogen anions and are the main contributors to the photoelectric properties of perovskites. X represents halogen anions, such as iodine (I), bromine (Br) or chlorine (Cl). Halogen anions together with metal cations form the inorganic layer of the perovskite, which has an important influence on the photoelectric properties of the perovskite. n represents an integer, which represents the metal halide octahedron ([BX6] 4-) The number of n determines the thickness of the inorganic layer and the degree of quantum confinement, which in turn affects the optoelectronic properties of the perovskite. When n = 1, it corresponds to a pure two-dimensional perovskite structure; when n = ∞, it is the traditional three-dimensional perovskite structure; and when 1 < n < ∞, it is a quasi-two-dimensional layered perovskite material. The octahedral perovskite structure is separated by n layers of organic ligand spacer layers to construct a quantum well structure with self-assembly characteristics. In the quasi-two-dimensional perovskite material, this unique structure results from a large dielectric mismatch, effectively spatially confining electrons and holes within the quantum well, promoting exciton formation, and thus enhancing the radiative recombination process. However, the introduced insulating organic spacer layer inevitably hinders the charge transfer mechanism in the quasi-two-dimensional perovskite, especially when the number of perovskite layers n ≤ 3 and the crystal orientation is preferentially parallel to the substrate, the situation is particularly significant. In this case, the inserted organic spacer layer forms a significant insulating barrier in the charge transport path, significantly reducing the conductivity of the quasi-two-dimensional perovskite thin film. This phenomenon severely restricts the efficiency performance of quasi-two-dimensional PeLEDs, resulting in a significant efficiency gap between photoluminescence (PL) and electroluminescence (EL).

[0004] Currently, the most commonly used method for preparing quasi-two-dimensional perovskite thin films is anti-solvent engineering. During the spin-coating process of the perovskite precursor solution, by dropping a solvent with a polarity opposite to that of the perovskite precursor solution (i.e., the anti-solvent), the growth of perovskite crystals is accelerated, and the generation of defects is reduced, thereby preparing high-quality perovskite thin films. However, solvent-treated polycrystalline perovskite thin films often carry many crystal defects, such as stoichiometric imbalance, amorphous regions, structural disorder, and unwanted phase mixtures formed due to incomplete growth during the rapid crystallization process. These defects act as charge traps, greatly promoting the trap-mediated non-radiative recombination process, resulting in energy loss. Notably, the surface of the perovskite thin film is often covered with a defect-rich region composed of intertwined broken crystals and amorphous phases. This layer not only exacerbates the non-radiative recombination phenomenon at the interface with the charge transport layer but also accelerates the degradation process of the perovskite material when exposed to the environment.

[0005] Therefore, it is urgent to provide a method for preparing quasi-two-dimensional perovskite thin films that aims to eliminate such crystal defects. Summary of the Invention

[0006] The present invention aims to solve at least one of the technical problems existing in the prior art. For this purpose, the present invention proposes a method for exfoliating and preparing quasi-two-dimensional perovskite thin films, which effectively removes the surface defect layer, further promotes the recrystallization process of quasi-two-dimensional perovskite crystals, significantly reduces the charge trap density, enhances the charge transport efficiency, and thus greatly improves the photoluminescence quantum yield (PLQY) of the exfoliated quasi-two-dimensional perovskite thin films.

[0007] A second aspect of the present invention provides an application of a method for preparing a quasi-two-dimensional perovskite film by exfoliation in preparing a perovskite light-emitting diode.

[0008] According to an embodiment of the first aspect of the present invention, a method for preparing a quasi-two-dimensional perovskite film by exfoliation is provided, comprising the following steps:

[0009] A1. Spin coating a perovskite precursor on a substrate surface to obtain a substrate coated with a thin film;

[0010] A2. Lay the tape on the substrate coated with the film, anneal and then peel off the tape.

[0011] The present invention uses a simple and efficient physical method to treat the surface of the perovskite film, namely, a scotch tape mechanical stripping method to prepare a quasi-two-dimensional perovskite film. This method has the advantages of simple operation, low cost, and no destruction of the inherent crystal structure of the material. The invention not only successfully stripped the surface layer of the quasi-two-dimensional perovskite film, but also exquisitely obtained a layer of high-quality film. This stripping process not only effectively removes the surface defect layer, but also promotes the recrystallization process of the quasi-two-dimensional perovskite crystal, significantly reduces the charge trap density, and enhances the charge transfer efficiency, thereby greatly improving the photoluminescence quantum yield (PLQY) of the quasi-two-dimensional perovskite film after stripping.

[0012] According to some embodiments of the present invention, in step A1, the substrate is a pre-treated substrate;

[0013] The pre-treatment steps include: cleaning, drying and surface treatment.

[0014] According to some embodiments of the present invention, the drying temperature is 100°C to 200°C.

[0015] According to some embodiments of the present invention, the surface treatment step includes: plasma cleaning the substrate for 5 min to 30 min.

[0016] According to some embodiments of the present invention, the spin coating rotation speed is 3000-5000 rpm, and the spin coating time is 30-200 s.

[0017] According to some embodiments of the present invention, the method for preparing the perovskite precursor comprises: dispersing and mixing cesium bromide, lead bromide and an organic ligand material at 30 to 80° C. for 4 to 6 hours.

[0018] According to some embodiments of the present invention, the organic ligand material includes at least one of p-fluorophenethylammonium bromide, p-fluorophenethylammonium chloride and p-nitrophenethylammonium bromide.

[0019] According to some embodiments of the invention, the solvent of the dispersing step comprises dimethyl sulfoxide.

[0020] According to some embodiments of the present invention, in the dispersed and mixed system, Pb 2+ The concentration is 0.10~0.5mmol / ml.

[0021] According to an embodiment of the first aspect of the present invention, an application of the method for preparing the quasi-two-dimensional perovskite film in preparing a perovskite light-emitting diode is proposed.

[0022] Other features and advantages of the present invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0024] Figure 1 This is a process flow chart for preparing a quasi-two-dimensional perovskite film in an embodiment;

[0025] Figure 2 The ultraviolet absorption spectra of the thin films prepared in Example 1 and Comparative Examples 1 to 3;

[0026] Figure 3 The photoluminescence (PL) spectra of the thin films prepared in Example 1 and Comparative Examples 1 to 3 are shown;

[0027] Figure 4 The data diagram of the fluorescence quantum yield (PLQY) of the thin films prepared in Example 1 and Comparative Examples 1 to 3;

[0028] Figure 5 The transient fluorescence lifetime diagrams of the thin films prepared in Example 1 and Comparative Examples 1-3.

[0029] Figure 6 The graphs are data on external quantum efficiency (EQE) and current density of perovskite light emitting diode (PeLED) devices using light emitting layer thin films prepared in Example 1 and Comparative Examples 1 to 3, respectively. DETAILED DESCRIPTION

[0030] The words "preferably", "more preferably", etc. in the present invention refer to embodiments of the present invention that may provide certain beneficial effects in certain circumstances. However, other embodiments may also be preferred under the same circumstances or other circumstances. In addition, the description of one or more preferred embodiments does not imply that other embodiments are not applicable, nor is it intended to exclude other embodiments from the scope of the present invention.

[0031] When a numerical range is disclosed herein, the above range is considered to be continuous and includes the minimum and maximum values ​​of the range, as well as every value between such minimum and maximum values. Further, when a range refers to an integer, every integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe features or characteristics, the ranges can be combined. In other words, unless otherwise indicated, all ranges disclosed herein should be understood to include any and all subranges included therein.

[0032] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of the present invention.

[0033] Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0034] Example 1

[0035] This embodiment provides a method for preparing a quasi-two-dimensional perovskite film by exfoliation, specifically:

[0036] S1. Configuration of perovskite precursor: Cesium bromide (CsBr), lead bromide (PbBr2), and p-fluorophenethylammonium bromide (pF-PEABr) were mixed at a ratio of 1:1:0.8. The solvent of all materials was dimethyl sulfoxide (DMSO). Finally, Pb in the system was kept 2+ The concentration of the prepared perovskite precursor solution was 0.10mmol / ml. The prepared perovskite precursor solution was placed in a glove box filled with nitrogen and heated on a hot plate at 40℃ in a dark environment for at least 4 hours.

[0037] S2. Perovskite film spin coating process:

[0038] S2.1 Clean the substrate by soaking it in a cleaning solution and using ultrasonic cleaning for 60 minutes, and then soaking it in ultrapure water and using ultrasonic cleaning for 60 minutes. During this process, the ultrapure water needs to be replaced every 20 minutes to ensure that there is no residual cleaning solution on the substrate;

[0039] S2.2 Dry the substrate. Place the cleaned substrate on a hot plate at 150°C for 5 minutes to ensure that there is no moisture on the entire substrate.

[0040] S2.3 Surface treatment: the dried substrate is plasma cleaned (PLASMA) for 15 min;

[0041] S2.4 Thin film spin coating: the surface treated substrate is transferred into a glove box filled with inert gas (N2), and the prepared perovskite precursor is spin coated on the substrate at a spin coating speed of 5000 rpm and a spin coating time of 60 s. After the spin coating is completed, the perovskite thin film before peeling is obtained;

[0042] S3. Peeling treatment: stick the transparent tape tightly on the substrate with the spin-coated film, and then anneal it on a hot plate at 75°C for 1 minute. After the annealing is completed, wait for the substrate to cool to room temperature, then gently peel off the transparent tape from the substrate to obtain the peeled perovskite film.

[0043] Figure 1 The process flow chart of preparing a quasi-two-dimensional perovskite film by mechanical stripping method in the above embodiment mainly includes: firstly preparing a perovskite film by spin coating, then bonding a layer of transparent plastic tape to the film for packaging, then placing it on a heating table at a certain temperature for annealing, cooling it at room temperature after a certain period of time, and finally slowly stripping off the transparent tape to obtain a perovskite film prepared by mechanical stripping method.

[0044] Example 2

[0045] This embodiment provides a method for preparing a quasi-two-dimensional perovskite film by exfoliation, specifically:

[0046] S1. Configuration of perovskite precursor: Cesium bromide (CsBr), lead bromide (PbBr2), and p-fluorophenethylammonium bromide (pF-PEABr) were mixed at a ratio of 1:1:0.8. The solvent of all materials was dimethyl sulfoxide (DMSO). 2+ The concentration of the prepared perovskite precursor solution was 0.30mmol / ml. The prepared perovskite precursor solution was placed in a glove box filled with nitrogen and heated on a hot plate at 40℃ in a dark environment for at least 4 hours.

[0047] S2. Perovskite film spin coating process:

[0048] S2.1 Clean the substrate by soaking it in a cleaning solution and using ultrasonic cleaning for 60 minutes, and then soaking it in ultrapure water and using ultrasonic cleaning for 60 minutes. During this process, the ultrapure water needs to be replaced every 20 minutes to ensure that there is no residual cleaning solution on the substrate;

[0049] S2.2 Dry the substrate. Place the cleaned substrate on a hot plate at 150°C for 5 minutes to ensure that there is no moisture on the entire substrate.

[0050] S2.3 Surface treatment: the dried substrate is plasma cleaned (PLASMA) for 15 min;

[0051] S2.4 Thin film spin coating: the surface treated substrate is transferred into a glove box filled with inert gas (N2), and the prepared perovskite precursor is spin coated on the substrate at a spin coating speed of 5000 rpm and a spin coating time of 60 s. After the spin coating is completed, the perovskite thin film before peeling is obtained;

[0052] S3. Peeling treatment: stick the transparent tape tightly on the substrate with the spin-coated film, and then anneal it on a hot plate at 75°C for 1 minute. After the annealing is completed, wait for the substrate to cool to room temperature, then gently peel off the transparent tape from the substrate to obtain the peeled perovskite film.

[0053] Example 3

[0054] This embodiment provides a method for preparing a quasi-two-dimensional perovskite film by exfoliation, specifically:

[0055] S1. Configuration of perovskite precursor: Cesium bromide (CsBr), lead bromide (PbBr2), and p-fluorophenethylammonium bromide (pF-PEABr) were mixed at a ratio of 1:1:0.8. The solvent of all materials was dimethyl sulfoxide (DMSO). 2+ The concentration of the prepared perovskite precursor solution was 0.20mmol / ml. The prepared perovskite precursor solution was placed in a glove box filled with nitrogen and heated on a hot plate at 40℃ in a dark environment for at least 4 hours.

[0056] S2. Perovskite film spin coating process:

[0057] S2.1 Clean the substrate by soaking it in a cleaning solution and using ultrasonic cleaning for 60 minutes, and then soaking it in ultrapure water and using ultrasonic cleaning for 60 minutes. During this process, the ultrapure water needs to be replaced every 20 minutes to ensure that there is no residual cleaning solution on the substrate;

[0058] S2.2 Dry the substrate. Place the cleaned substrate on a hot plate at 150°C for 5 minutes to ensure that there is no moisture on the entire substrate.

[0059] S2.3 Surface treatment: the dried substrate is plasma cleaned (PLASMA) for 15 min;

[0060] S2.4 Thin film spin coating: the surface treated substrate is transferred into a glove box filled with inert gas (N2), and the prepared perovskite precursor is spin coated on the substrate at a spin coating speed of 5000 rpm and a spin coating time of 60 s. After the spin coating is completed, the perovskite thin film before peeling is obtained;

[0061] S3. Peeling treatment: stick the transparent tape tightly on the substrate with the spin-coated film, and then anneal it on a hot plate at 75°C for 1 minute. After the annealing is completed, wait for the substrate to cool to room temperature, then gently peel off the transparent tape from the substrate to obtain the peeled perovskite film.

[0062] Example 4

[0063] This embodiment provides a method for preparing a quasi-two-dimensional perovskite film by exfoliation, specifically:

[0064] S1. Configuration of perovskite precursor: Cesium bromide (CsBr), lead bromide (PbBr2), and p-fluorophenethylammonium bromide (pF-PEABr) were mixed at a ratio of 1:1:0.8. The solvent of all materials was dimethyl sulfoxide (DMSO). 2+ The concentration of the prepared perovskite precursor solution was 0.50mmol / ml. The prepared perovskite precursor solution was placed in a glove box filled with nitrogen and heated on a hot plate at 40℃ in a dark environment for at least 4 hours.

[0065] S2. Perovskite film spin coating process:

[0066] S2.1 Clean the substrate by soaking it in a cleaning solution and using ultrasonic cleaning for 60 minutes, and then soaking it in ultrapure water and using ultrasonic cleaning for 60 minutes. During this process, the ultrapure water needs to be replaced every 20 minutes to ensure that there is no residual cleaning solution on the substrate;

[0067] S2.2 Dry the substrate. Place the cleaned substrate on a hot plate at 150°C for 5 minutes to ensure that there is no moisture on the entire substrate.

[0068] S2.3 Surface treatment: the dried substrate is plasma cleaned (PLASMA) for 15 min;

[0069] S2.4 Thin film spin coating: the surface treated substrate is transferred into a glove box filled with inert gas (N2), and the prepared perovskite precursor is spin coated on the substrate at a spin coating speed of 5000 rpm and a spin coating time of 60 s. After the spin coating is completed, the perovskite thin film before peeling is obtained;

[0070] S3. Peeling treatment: stick the transparent tape tightly on the substrate with the spin-coated film, and then anneal it on a hot plate at 75°C for 1 minute. After the annealing is completed, wait for the substrate to cool to room temperature, then gently peel off the transparent tape from the substrate to obtain the peeled perovskite film.

[0071] Comparative Example 1

[0072] This comparative example provides a method for preparing a quasi-two-dimensional perovskite film by exfoliation, specifically:

[0073] The difference between this comparative example and Example 1 is that the perovskite film spin coating process does not use a stripping treatment, and is directly placed on a hot plate at 75° C. for annealing. The annealing time is 1 minute. After the annealing is completed, the substrate is cooled to room temperature to obtain a treated perovskite film.

[0074] Comparative Example 2

[0075] This comparative example provides a method for preparing a quasi-two-dimensional perovskite film by exfoliation, specifically:

[0076] The difference between this comparative example and Example 1 is that anti-solvent engineering is used to treat the perovskite film in the spin coating process, that is, the surface-treated substrate is transferred into a glove box filled with inert gas (N2), and the configured perovskite precursor is spin-coated on the substrate. The spin coating speed is 5000rpm and the spin coating time is 60s. At the 20th second of spin coating, 100ul of chlorobenzene solution is quickly added to perform rapid crystallization treatment on the film. After that, the film is not peeled off, but annealing is directly performed on a hot stage at 75°C for 1min. After the annealing is completed, the substrate is cooled to room temperature to obtain the treated perovskite film.

[0077] Comparative Example 3

[0078] This comparative example provides a method for preparing a quasi-two-dimensional perovskite film by exfoliation, specifically:

[0079] The difference between this comparative example and Example 1 is that anti-solvent engineering is used to treat the perovskite film in the spin coating process, that is, the surface-treated substrate is transferred into a glove box filled with inert gas (N2), and the configured perovskite precursor is spin-coated on the substrate. The spin coating speed is 5000 rpm and the spin coating time is 60 s. At the 20th second of spin coating, 100 ul of ethyl acetate solution is quickly added to perform rapid crystallization treatment on the film. After that, the film is not peeled off, but annealing is directly performed on a hot stage at 75°C for 1 min. After the annealing is completed, the substrate is cooled to room temperature to obtain the treated perovskite film.

[0080] Test example

[0081] Figure 2The ultraviolet absorption spectra of the films prepared by four methods are shown in Example 1 (stripping method) and Comparative Example 1 (no treatment), Comparative Example 2 (anti-solvent chlorobenzene) and Comparative Example 3 (anti-solvent ethyl acetate). According to the test results, the application of the mechanical stripping method on the n=3 phase significantly reduces its absorption peak. This finding strongly reveals the inhibitory effect of the method on the low-dimensional phase (n≤3) in the quasi-two-dimensional perovskite film. According to authoritative literature, there are significant differences in the formation energy of each n phase in the quasi-two-dimensional perovskite film. Among them, the low n phase (such as n≤3) has a lower formation energy and is easy to dominate in the rapid crystallization process of the film, thereby causing the uneven distribution of the n phase. This uneven distribution of n phases directly restricts the effective injection of carriers and the efficiency of energy transfer. In particular, when the low n phase is over-enriched, it will significantly weaken the energy transfer to the high n phase, which will have an adverse effect on the overall performance of the device. Therefore, as an effective means of regulation, the mechanical stripping method can accurately adjust the distribution pattern of the n phase in the film, which not only effectively curbs the excessive generation of the low n phase, but also promotes the further development and formation of the high n phase. As the proportion of high n-phase gradually increases, the perovskite film exhibits more excellent microstructural characteristics: the grain size increases significantly and the number of grain boundaries decreases accordingly. This series of changes not only reduces the density of defect states, but also significantly enhances the structural stability of the film.

[0082] Figure 3 The photoluminescence (PL) spectra of the films prepared by the four methods of Example 1 (stripping method), Comparative Example 1 (no treatment), Comparative Example 2 (anti-solvent chlorobenzene) and Comparative Example 3 (anti-solvent ethyl acetate) are shown. According to the test results, the PL peaks of the films prepared by the mechanical stripping method, no treatment and anti-solvent chlorobenzene are all 504nm, while the PL peak of the film prepared by the anti-solvent ethyl acetate is 508nm. It can be found that the mechanical stripping method treatment does not change the PL spectrum of the film itself (no treatment).

[0083] Figure 4 The data graphs show the fluorescence quantum yield (PLQY) of the films prepared by four methods, namely, Example 1 (stripping method) and Comparative Example 1 (no treatment), Comparative Example 2 (anti-solvent chlorobenzene) and Comparative Example 3 (anti-solvent ethyl acetate). According to the data results, under 320nm wavelength excitation, the PLQY of the film prepared by the mechanical stripping method is 68%, which is much higher than the films prepared by no treatment (PLQY is 8%), anti-solvent chlorobenzene (PLQY is 26%) and anti-solvent ethyl acetate (PLQY is 21%). This fully demonstrates that the film treated by the mechanical stripping method effectively suppresses the non-radiative process, thereby reducing energy loss and making the film have better luminous efficiency. At the same time, the higher PLQY also shows that the better film quality can be obtained by the mechanical stripping method, which means that a film with better crystallinity, fewer defects and more uniform phase distribution is obtained by this physical method.

[0084] Figure 5 The transient fluorescence lifetime diagram of the film prepared by Example 1 (stripping method) and Comparative Example 1 (no treatment) and Comparative Example 2 (anti-solvent chlorobenzene). According to the data results, under 375nm laser excitation, the fluorescence lifetime of the film prepared by the mechanical stripping method is significantly longer than that of the film prepared by the untreated and anti-solvent chlorobenzene. In order to more accurately analyze the fluorescence lifetime of the film under different process preparation methods, a three-exponential function was used to fit the test results. The analysis data is shown in Table 1. The average lifetime (τ avg ) is 29.62ns, which is significantly higher than the film prepared by the untreated comparative example 1 (16.20ns) and the anti-solvent chlorobenzene (18.64ns) of comparative example 2. According to research, defects and traps are important factors leading to non-radiative recombination in perovskite films. These defects and traps can capture excitons and prevent them from releasing energy through radiative recombination, thereby shortening the fluorescence lifetime. Therefore, a longer fluorescence lifetime indicates that there are fewer defects and traps in the film, which is conducive to improving the radiative recombination efficiency of excitons and thus improving the luminescence performance.

[0085] Figure 6 The external quantum efficiency (EQE) and current density data of the perovskite light-emitting diode (PeLED) device prepared by the four methods of Example 1 (stripping method) and Comparative Example 1 (no treatment), Comparative Example 2 (anti-solvent chlorobenzene) and Comparative Example 3 (anti-solvent ethyl acetate) are shown. According to the data results, the EQE of the device prepared by the stripping method is 7.4%, which is much higher than the device prepared by the methods of no treatment (EQE is 1.1%), anti-solvent chlorobenzene (EQE is 4.5%) and anti-solvent ethyl acetate (EQE is 4.5%). It further proves that the quasi-two-dimensional perovskite film prepared by mechanical stripping has obvious advantages over the traditional method.

[0086] The present invention is not limited to the above-mentioned embodiments, and various changes can be made within the knowledge of ordinary technicians in the relevant technical field without departing from the purpose of the present invention. In addition, the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

Claims

1. A method for preparing quasi-two-dimensional perovskite films by exfoliation, It is characterized in that The following steps are involved: A1. Spin coating a perovskite precursor on a substrate surface to obtain a substrate coated with a thin film; A2. Lay the tape on the substrate coated with the film, anneal and then peel off the tape.

2. The method for preparing a quasi-two-dimensional perovskite film by exfoliation according to claim 1, It is characterized in that In step A1, the substrate is a pre-treated substrate; The pre-treatment steps include: cleaning, drying and surface treatment.

3. The method for preparing a quasi-two-dimensional perovskite film by exfoliation according to claim 2, It is characterized in that The drying temperature is 100°C to 200°C.

4. The method for preparing a quasi-two-dimensional perovskite film by exfoliation according to claim 2, It is characterized in that The surface treatment step includes: plasma cleaning the substrate for 5 minutes to 30 minutes.

5. The method for preparing a quasi-two-dimensional perovskite film by exfoliation according to claim 1, It is characterized in that The rotation speed of the spin coating is 3000-5000 rpm, and the time of the spin coating is 30-200 s.

6. The method for preparing a quasi-two-dimensional perovskite film by exfoliation according to claim 1, It is characterized in that The preparation method of the perovskite precursor comprises: dispersing and mixing cesium bromide, lead bromide and an organic ligand material, and heating at 30-80° C. for 4-6 hours.

7. The method for preparing a quasi-two-dimensional perovskite film by exfoliation according to claim 6, It is characterized in that The organic ligand material includes at least one of p-fluorophenethylammonium bromide, p-fluorophenethylammonium chloride and p-nitrophenethylammonium bromide.

8. The method for preparing a quasi-two-dimensional perovskite film by exfoliation according to claim 6, It is characterized in that The solvent of the dispersing step includes dimethyl sulfoxide.

9. The method for preparing a quasi-two-dimensional perovskite film by exfoliation according to claim 6, It is characterized in that In the dispersed and mixed system, Pb 2+ The concentration is 0.10~0.5mmol / ml.

10. Use of the method for preparing a quasi-two-dimensional perovskite film by exfoliation as claimed in any one of claims 1 to 9 in preparing a perovskite light-emitting diode.

Images