A method for studying the crystal orientation mechanism of quasi-two-dimensional perovskite blue light emitting diodes

Abstract

The application discloses a kind of quasi-two-dimensional perovskite blue light LED's crystal orientation mechanism regulation research method, belong to display technical field, first establish quasi-two-dimensional blue light perovskite vertical growth theoretical model in the present application, construct theoretical basis, then through experiment, analysis different substrate and antisolvent temperature and substrate assembly process etc. Find the influence of different film forming process on quasi-two-dimensional blue light perovskite crystalline orientation, solve the problem that substrate and antisolvent temperature temperature hinder quasi-two-dimensional blue light perovskite light-emitting diode exciton radiative recombination, finally by analyzing the influence of different crystalline orientation on blue light PeLEDs performance to select more suitable process, and prepare high-performance blue light PeLEDs device, the present application is carried out complete experiment by quasi-two-dimensional blue light perovskite crystalline orientation different under different conditions, structure and process, and the influence of different crystal orientation on quasi-two-dimensional blue light PeLEDs performance, and develop blue light PeLEDs device.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of display, and particularly relates to a crystal orientation mechanism regulation research method of quasi-two-dimensional perovskite blue light LED. BACKGROUND

[0002] The research and development process of blue light emitting diodes is very arduous. In the early stage, although red and green LEDs have been successfully commercialized, the manufacture of blue LEDs has always been a problem. Until the 1990s, Japanese scientist Shuji Nakamura successfully manufactured high-brightness blue LEDs while working at Nichia Chemical Industries. Blue light perovskite light-emitting diodes (PeLEDs) are the core technical bottleneck for the rapid development of perovskite full-color display and white light illumination technology. Quasi-two-dimensional perovskite can realize blue light emission by adjusting the number of layers and quantum confinement effect, and can significantly improve the stability of the film layer and the device by means of its hydrophobic organic ligand, and has become a research hotspot in the field of perovskite.

[0003] Quasi-two-dimensional blue light perovskite has been gradually applied to the preparation of sky blue PeLEDs since 2016. However, the following three different structures of perovskite are explained. Three-dimensional (3D) perovskite is formed by alternating organic and inorganic components in three-dimensional space, two-dimensional (2D) perovskite is formed by two components alternating in sheet structure, and quasi-two-dimensional (Q2D) perovskite is a mixed structure of the two types of perovskite, that is, a three-dimensional perovskite of different sizes is wrapped by a large-size organic shell layer. The research on perovskite blue light emitting materials and blue light emitting diodes is still relatively lagging behind. Pure 2D perovskite has poor transport characteristics, and 3D perovskite is also unstable. SUMMARY

[0004] The present application proposes a crystal orientation mechanism regulation research method of quasi-two-dimensional perovskite blue light LED to solve the problems in the prior art that the research on perovskite blue light emitting materials and blue light emitting diodes is still relatively lagging behind, and pure 2D perovskite has poor transport characteristics and 3D perovskite is also unstable.

[0005] The technical scheme adopted by the present application is as follows:

[0006] A crystal orientation mechanism regulation research method of quasi-two-dimensional perovskite blue light LED, comprising the following steps:

[0007] Step 1: Establish a perovskite crystal growth process model, analyze the fine structure and morphology characteristics of quasi-two-dimensional blue light perovskite, and study the theoretical model and internal mechanism of film forming process regulating quasi-two-dimensional blue light perovskite crystal growth;

[0008] Step 2: Explore the influence of the interaction between organic long-chain cations and three-dimensional crystals on the alignment of two-dimensional blue light perovskite crystals by adjusting the substrate, anti-solvent temperature conditions;

[0009] Step 3: Modify the substrate layer using self-assembly and wetting enhancement methods to explore the influence of different substrate layer surface properties on the growth orientation of two-dimensional blue light perovskite;

[0010] Step 4: Combine theoretical simulation calculations to change the different orientation parameters of quasi-two-dimensional blue light perovskite material crystals, and verify the growth mechanism of quasi-two-dimensional blue light perovskite crystal orientation;

[0011] Step 5: Since the quality and orientation of quasi-two-dimensional blue light perovskite crystals change, some physical properties of quasi-two-dimensional blue light perovskite thin films will also change. Through experiments, explore the change rules of crystal structure, defect state, charge transport, and photophysical characteristics caused by changes in crystal orientation under various growth conditions;

[0012] Step 6: Through the testing of the change rules of quasi-two-dimensional blue light perovskite crystals caused by growth conditions, select quasi-two-dimensional blue light perovskite structures that have a positive effect on device performance improvement, and establish a mutual relationship with the efficiency of the corresponding blue light devices;

[0013] Step 7: Through interface regulation and process optimization, regulate the preparation process of quasi-two-dimensional blue light perovskite vertical growth, regulate the vertical growth of quasi-two-dimensional blue light perovskite, promote the transport of carriers in the functional layer interface and the light-emitting layer, and develop blue PeLEDs devices.

[0014] Preferably, the specific steps of step 1 are as follows:

[0015] Step 1.1: Establish and improve the theoretical model of quasi-two-dimensional blue light perovskite blue light devices based on crystal vertical growth, use the island growth model of polycrystalline thin film crystals, perovskite interface growth model, and carrier transport model to establish the kinetic model of inorganic crystal vertical growth in quasi-two-dimensional blue light perovskite;

[0016] Step 1.2: Simulate the influence of substrate temperature on the crystalline orientation of two-dimensional blue light perovskite thin films in different film formation processes;

[0017] Step 1.3: Research the internal rules of quasi-two-dimensional blue light perovskite crystal growth mechanism and thermodynamics, and form organic ligands of quasi-two-dimensional blue light perovskite, which mostly contain saturated long chains, limiting the charge transport between inorganic frameworks, and constructing vertical crystal orientation with the substrate.

[0018] Preferably, the specific steps of step 2 are as follows:

[0019] Step 2.1: Using PbBr2, MABr, CsBr, PEABr materials as raw materials, the raw materials are dissolved in N, N-dimethylacetamide solvent, dimethyl sulfoxide solvent or mixed solvent of the two solvents according to different proportions;

[0020] Step 2.2: The preheating temperature of the substrate is set in a gradient from room temperature to 180°C, and every 5°C is taken as a sample. For quasi-two-dimensional blue light perovskite thin film, scanning electron microscopy and X-ray diffraction techniques are used to characterize the crystallization status and crystal orientation of quasi-two-dimensional blue light perovskite at different preheating temperatures.

[0021] Step 2.3: The effect of thermal injection anti-solvent on the crystalline orientation of quasi-two-dimensional blue light perovskite is analyzed. First, the boiling points of different anti-solvents are determined, and the temperature of the anti-solvent is set in a gradient from room temperature to boiling point, and every 5°C is taken as a sample. At the same time, for the quasi-two-dimensional blue light perovskite thin film prepared, scanning electron microscopy and X-ray diffraction techniques are used to characterize the crystallization status and crystal orientation of quasi-two-dimensional blue light perovskite at different preheating temperatures.

[0022] Preferably, the specific steps of step 3 are as follows:

[0023] Step 3.1: The effect of the transport layer interface of quasi-two-dimensional blue light perovskite growth on the crystalline orientation of quasi-two-dimensional blue light perovskite is analyzed and simulated using PIN type device structure.

[0024] Step 3.2: Using oxide, small molecule and polymer as hole transport layer respectively, the effects of different hole transport layer film wettability, functional group, roughness, microstructure on crystalline orientation are analyzed to determine the conditions for obtaining vertical growth.

[0025] Preferably, the specific steps of step 5 are as follows:

[0026] Step 5.1: The energy level matching in quasi-two-dimensional blue light perovskite is studied by studying the electronic energy level of quasi-two-dimensional blue light perovskite at different surface depths using ion etching method.

[0027] Step 5.2: Single charge transport device is prepared, and the mobility of vertical growth quasi-two-dimensional blue light perovskite thin film and control film is analyzed by using space charge limited current model, so as to study the effect of charge transport in quasi-two-dimensional blue light perovskite.

[0028] Preferably, the specific steps of step 6 are as follows:

[0029] Step 6.1: Steady-state and transient luminescence spectrum test is carried out on the quasi-two-dimensional blue light perovskite thin film grown in the way, and by comparing the luminescence intensity, luminescence peak position and luminescence lifetime characteristics, the exciton radiation and non-radiation recombination process of quasi-two-dimensional blue light perovskite thin film are studied, and the exciton lifetime status in quasi-two-dimensional blue light perovskite is analyzed.

[0030] Step 6.2: Modify the wettability of the quasi-two-dimensional blue light perovskite lower interface buffer layer, further adjust the grain boundary size of the quasi-two-dimensional blue light perovskite, and enhance the exciton radiative recombination of the quasi-two-dimensional blue light perovskite, so as to study the exciton radiative recombination mode of the vertically grown thin film;

[0031] Step 6.3: According to the characteristics of the quasi-two-dimensional blue light perovskite material, adopt a suitable blue light device preparation process, including screening different P-type semiconductor and N-type semiconductor materials as hole and electron transport layers, respectively, to balance the hole and electron transport capabilities of the device, and broaden the light emitting area.

[0032] In summary, due to the adoption of the above technical solutions, the beneficial effects of the present application are: BRIEF DESCRIPTION OF DRAWINGS

[0033] Fig. 1 The flowchart of the present application is shown in the figure;

[0034] Fig. 2 The blue light PeLEDs device structure of the present application is shown in the figure;

[0035] Fig. 3 The structure of the quasi-two-dimensional blue light perovskite of the present application is shown in the figure. DETAILED DESCRIPTION

[0036] All features disclosed in this specification, or all steps of any methods or processes disclosed, may be combined in any combination, except where such combinations are mutually exclusive.

[0037] The following will be combined Figs. 1 to 3 to make a detailed description of the present application.

[0038] Example 1

[0039] A method for studying the crystal orientation mechanism of a quasi-two-dimensional perovskite blue light LED, as shown in Fig. 1 , Fig. 2 , Fig. 3 , includes the following steps:

[0040] Step 1: Establish a perovskite crystal growth process model, analyze the fine structure and morphology of the quasi-two-dimensional blue light perovskite, and study the theoretical model and internal mechanism of the film formation process for controlling the growth of the quasi-two-dimensional blue light perovskite, and the specific steps of step 1 are as follows:

[0041] Step 1.1: Establish and improve the theoretical model of the quasi-two-dimensional blue light perovskite blue light device based on vertical growth of inorganic crystals, and establish the kinetic model of vertical growth of inorganic crystals in the quasi-two-dimensional blue light perovskite by using the island growth model of polycrystalline thin film, the perovskite interface growth model and the carrier transport model;

[0042] Step 1.2: Simulate the influence of substrate temperature on the crystalline orientation of quasi-two-dimensional blue perovskite films in different film-forming processes;

[0043] Step 1.3: Study the internal laws of quasi-two-dimensional blue perovskite crystal growth mechanism and crystal growth thermodynamics, and form quasi-two-dimensional blue perovskite organic ligands which mostly contain saturated long chains, limiting charge transfer between inorganic frameworks, and constructing crystal orientation perpendicular to the substrate;

[0044] Step 2: Adjust the substrate and antisolvent temperature conditions to explore the influence of the interaction between organic long-chain cations and three-dimensional crystals on the orientation of quasi-two-dimensional blue perovskite crystals, and the specific steps of Step 2 are as follows:

[0045] Step 2.1: Use PbBr2, MABr, CsBr, and PEABr materials as raw materials, and dissolve the raw materials in N,N-dimethylacetamide solvent, dimethyl sulfoxide solvent, or a mixture of the two solvents according to different proportions;

[0046] Step 2.2: Set the preheating temperature of the substrate in a gradient from room temperature to 180°C, with every 5°C as a sample. For quasi-two-dimensional blue perovskite films, use scanning electron microscopy and X-ray diffraction techniques to characterize the crystalline state and crystal orientation of quasi-two-dimensional blue perovskite at different preheating temperatures;

[0047] Step 2.3: Study the influence of hot injection of antisolvents on the orientation of quasi-two-dimensional blue perovskite crystals. First, determine the boiling points of different antisolvents, and set the antisolvent temperature in a gradient from room temperature to boiling point, with every 5°C as a sample. Meanwhile, for the prepared quasi-two-dimensional blue perovskite films, use scanning electron microscopy and X-ray diffraction techniques to characterize the crystalline state and crystal orientation of quasi-two-dimensional blue perovskite at different preheating temperatures;

[0048] In Step 2 of the present application, when exploring the influence of different substrate temperatures on the orientation of quasi-two-dimensional perovskite crystals, the substrate temperature and antisolvent temperature are set in an equal-interval gradient: the substrate temperature is from room temperature to 180°C, and the antisolvent temperature is from room temperature to boiling point, with 5°C as the progressive value. High-performance scanning electron microscopy and X-ray diffraction techniques are used to clearly characterize the crystalline state and crystal orientation of quasi-two-dimensional perovskite at different preheating temperatures and antisolvent temperatures. The experimental data not only includes the crystal state at each theoretically feasible temperature, but also increases the accuracy and convenience of observation of the experiment using advanced equipment and techniques.

[0049] Step 3: Modify the substrate layer using self-assembly and wetting enhancement methods to explore the influence of different substrate layer surface properties on the growth orientation of quasi-two-dimensional blue perovskite, and the specific steps of Step 3 are as follows:

[0050] Step 3.1: Analysis and simulation of the influence of the alignment of the transport layer interface on the crystalline orientation of the two-dimensional blue light perovskite using a PIN-type device structure;

[0051] Step 3.2: Analysis of the influence of the film wettability, functional groups, roughness, and microstructure of different hole transport layers on the crystalline orientation by using oxides, small molecules, and polymers as hole transport layers, respectively, to determine the conditions for vertical growth;

[0052] Step 4: Verification of the growth mechanism of the quasi-two-dimensional blue light perovskite crystalline orientation by changing the different orientation parameters of the quasi-two-dimensional blue light perovskite material crystallization combined with theoretical simulation calculations;

[0053] Step 5: Since the quality and orientation of the quasi-two-dimensional blue light perovskite crystal change, some physical properties of the quasi-two-dimensional blue light perovskite film also change. The change rules of the crystal structure, defect state, charge transport, and photophysical characteristics of the quasi-two-dimensional blue light perovskite under various growth conditions are explored through experiments. The specific steps of Step 5 are as follows:

[0054] Step 5.1: Study of the energy level matching in the quasi-two-dimensional blue light perovskite by studying the electronic energy levels of different surface depths of the quasi-two-dimensional blue light perovskite using ion etching;

[0055] Step 5.2: Preparation of single charge transport devices and analysis of the mobility of the vertically grown quasi-two-dimensional blue light perovskite film and the control film using the space charge limited current model to study the influence of charge transport in the quasi-two-dimensional blue light perovskite;

[0056] In Step 5 of the present application, ion etching and single charge transport devices are used, and the space charge limited current model is used. The electronic energy levels of different surface depths are studied, and the mobility of the vertically grown quasi-two-dimensional blue light perovskite film and the control film is analyzed accurately, providing a reference for subsequent enhancement of exciton radiative recombination.

[0057] Step 6: Through the testing of the change rules of the quasi-two-dimensional blue light perovskite crystal caused by the growth conditions, the quasi-two-dimensional blue light perovskite structure that positively affects the device performance is selected, and the efficiency of the corresponding blue light device is established, and the specific steps of Step 6 are as follows:

[0058] Step 6.1: Steady-state and transient luminescence spectrum testing of the quasi-two-dimensional blue light perovskite film grown in the growth mode, comparison of the luminescence intensity, luminescence peak position, and luminescence lifetime characteristics, study of the exciton radiative and non-radiative recombination processes of the quasi-two-dimensional blue light perovskite film, and analysis of the exciton lifetime in the quasi-two-dimensional blue light perovskite;

[0059] Step 6.2: Modify the wettability of the quasi-two-dimensional blue light perovskite lower interface buffer layer to further adjust the grain boundary size of the quasi-two-dimensional blue light perovskite, so as to enhance the exciton radiative recombination of the quasi-two-dimensional blue light perovskite, thereby studying the exciton radiative recombination mode of the vertically grown thin film;

[0060] Step 6.3: According to the characteristics of the quasi-two-dimensional blue light perovskite material, adopt appropriate blue light device preparation process, including screening different P-type semiconductor and N-type semiconductor materials as hole and electron transport layer respectively, so as to balance the hole and electron transport ability of the device and widen the light emitting area;

[0061] In step 6.1 of the present application, the quasi-two-dimensional blue light perovskite thin film grown in the way is tested by steady-state and transient luminescence spectrum, and the exciton lifetime condition in the quasi-two-dimensional blue light perovskite is analyzed.

[0062] In step 6.2 of the present application, in order to solve the problem that temperature hinders the exciton radiative recombination of the quasi-two-dimensional blue light perovskite light emitting diode, the quasi-two-dimensional blue light perovskite structure is improved, the wettability of the quasi-two-dimensional blue light perovskite lower interface buffer layer is modified, and the exciton radiative recombination of the quasi-two-dimensional blue light perovskite is enhanced.

[0063] In step 6.3 of the present application, the hole and electron transport layer is adjusted to further balance the hole and electron transport ability of the device, widen the light emitting area, and improve the electron transport ability and light emitting performance of the blue light PeLEDs device.

[0064] Step 7: Through interface regulation and process optimization, the preparation process of the quasi-two-dimensional blue light perovskite vertical growth is regulated, the vertical growth of the quasi-two-dimensional blue light perovskite crystal is regulated, the carrier transport in the functional layer interface and the light emitting layer is promoted, and the blue light PeLEDs device is developed.

[0065] In this embodiment, the influence of different conditions on crystal growth in the crystallization process is analyzed in depth, the optimal solution for the vertical growth of the quasi-two-dimensional blue light perovskite crystal is obtained, and through optimization of experimental techniques and methods, the manufacturing process is improved to solve the problem that when the temperature of the substrate is higher than the crystallization temperature of the quasi-two-dimensional blue light perovskite phase, there is no intermediate phase conversion stage to the quasi-two-dimensional blue light perovskite crystal, which leads to the formation of larger grain boundaries of the quasi-two-dimensional blue light perovskite crystal, thereby hindering the exciton radiative recombination of the quasi-two-dimensional blue light perovskite light emitting diode, and finally a high-efficiency and stable blue light PeLEDs device is developed.

[0066] Based on the theoretical basis of quasi-two-dimensional blue light PeLEDs based on crystal vertical growth, the theoretical model of quasi-two-dimensional blue light perovskite vertical growth is established based on the thermodynamic analysis of multi-component system crystal growth, the nucleation principle and kinetic model of crystal growth process, which provides theoretical support for the preparation and optimization of quasi-two-dimensional blue light perovskite crystal thin film. Specifically, (1) according to the crystal orientation, dimension and material composition in the quasi-two-dimensional blue light perovskite thin film, combined with its film forming process, the influencing factors of optical and electrical properties of quasi-two-dimensional blue light perovskite thin film are summarized; (2) the functional layer parameter simulation of the optical and electrical properties and film thickness of the substrate, transparent electrode material, host material, quasi-two-dimensional blue light perovskite material, charge transport material, metal electrode material and packaging material is established; (3) the optical structure and theoretical simulation of blue light PeLEDs are studied, and the device optical model of visible light emission efficiency and external quantum efficiency is established.

[0067] The following work is done on the influence of different film forming processes on the orientation of quasi-two-dimensional blue light perovskite crystals: (1) the introduction method, ratio concentration and annealing temperature process conditions of organic long-chain amine salt are explored, and the control factors of different quasi-two-dimensional blue light perovskite inorganic skeleton layer number in the film are analyzed; (2) by adjusting the substrate temperature and antisolvent temperature, the influence of heat change on the growth orientation of quasi-two-dimensional blue light perovskite in the crystallization process is analyzed; (3) the substrate layer is modified by using self-assembly and wetting methods, and the influence of different substrate layer surface properties on the growth orientation of quasi-two-dimensional blue light perovskite is explored; (4) combined with theoretical simulation calculation, the different orientation parameters of material crystallization are changed, and the growth mechanism of quasi-two-dimensional blue light perovskite crystal orientation is verified. Through screening, the temperature and substrate of the most efficient quasi-two-dimensional blue light perovskite are obtained. Finally, by trying different charge injection methods, quasi-two-dimensional blue light perovskite is used as the light emitting layer to prepare blue light PeLEDs, the performance of blue light devices is characterized, the influence mechanism of quasi-two-dimensional blue light perovskite thin film crystal orientation on device efficiency is analyzed, and blue light PeLEDs are prepared.

[0068] The above is only the preferred embodiment of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art can think of changes or replacements within the technical range disclosed by the present application without creative labor, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be limited by the protection scope defined in the claims.

Claims

1. A method for studying the crystalline orientation of quasi-two-dimensional blue light perovskite LEDs and its regulation mechanism, comprising the following steps: Step 1: establishing a perovskite crystal growth process model, analyzing the fine structure and morphology characteristics of quasi-two-dimensional perovskite, and studying the theoretical model and internal mechanism of film formation process regulating perovskite crystal growth; Step 2: by adjusting the substrate and antisolvent temperature conditions, explore the influence of the interaction between organic long-chain cations and three-dimensional crystals on the crystal orientation; Step 3: using self-assembly and wetting methods to modify the substrate layer, explore the influence of different substrate layer surface properties on the growth orientation of quasi-two-dimensional perovskite; Step 4: combined with theoretical simulation calculation, change the different orientation parameters of material crystallization, verify the growth mechanism of quasi-two-dimensional perovskite crystalline orientation; Step 5: due to the change of quasi-two-dimensional perovskite crystalline quality and crystalline orientation, part of the physical properties of perovskite film will also change, through experiments to explore the change rule of perovskite crystal structure, defect state, charge transport, and optical physical characteristics under various growth conditions; Step 6: by testing the change rule of perovskite crystal caused by growth conditions, select quasi-two-dimensional perovskite structure which has positive effect on device performance improvement, and establish the mutual relationship with the efficiency of corresponding blue light device; Step 7: by interface regulation and process optimization and preparation process of regulating perovskite vertical growth, regulate quasi-two-dimensional perovskite vertical crystal growth, promote the carrier transport in the functional layer interface and the light-emitting layer, and develop blue PeLEDs device; The specific steps of step 1 are as follows: Step 1.1: establish and improve the theoretical model of quasi-two-dimensional perovskite blue light device based on vertical growth of crystal, adopt island growth model of polycrystalline thin film crystallization, perovskite interface growth model and carrier transport model to establish the kinetic model of vertical growth of inorganic crystal in quasi-two-dimensional perovskite; Step 1.2: simulate the influence of substrate temperature on the crystalline orientation of quasi-two-dimensional perovskite thin film in different film formation processes; Step 1.3: study the internal law of quasi-two-dimensional perovskite crystal growth mechanism and crystal growth thermodynamics, form the organic ligand of quasi-two-dimensional perovskite which mostly contains saturated long chain, limit the charge transport between inorganic framework, and construct the crystal orientation perpendicular to the substrate.

2. The method of claim 1, wherein the quasi-two-dimensional blue perovskite LED is grown on a substrate, and the substrate is selected from the group consisting of GaAs, GaP, GaN, InP, InAs, InN, AlAs, AlP, AlN, Si, Ge, and combinations thereof. The specific steps of step 2 are as follows: Step 2.1: using PbBr2, MABr, CsBr, PEABr materials as raw materials, dissolving the raw materials in N, N-dimethylacetamide solvent, dimethyl sulfoxide solvent or mixed solvent of the two solvents according to different proportions; Step 2.2: set the preheating temperature of the substrate in gradient, from room temperature to 180°C, every 5°C as a sample, for perovskite thin film, use scanning electron microscopy and X-ray diffraction technology to characterize the crystalline state and crystal orientation of quasi-two-dimensional perovskite under different preheating temperatures; Step 2.3: Effect of alignment of two-dimensional perovskite crystal orientation by hot injection of anti-solvent, first determine the boiling point of different anti-solvents to be used, set the temperature of the anti-solvent gradient, from room temperature to boiling point, every 5°C as a sample, at the same time, for the perovskite thin film prepared, use scanning electron microscopy and X-ray diffraction technology to characterize the two-dimensional perovskite crystal and crystal orientation under different preheating temperatures.

3. The method for studying the crystal orientation and its control mechanism of a quasi-two-dimensional blue perovskite LED as described in claim 1, characterized in that, The specific steps of step 3 are as follows: Step 3.1: Analysis and pre-visualization of the effect of the transport layer interface of perovskite growth on the alignment of two-dimensional perovskite crystal orientation using PIN device structure; Step 3.2: Using oxides, small molecules, and polymers as hole transport layers, respectively, to analyze the effects of different hole transport layer film wettability, functional groups, roughness, and microstructure on crystal orientation, and determine the conditions for vertical growth.

4. The method for studying the crystal orientation and its control mechanism of a quasi-two-dimensional blue perovskite LED as described in claim 1, characterized in that, The specific steps of step 5 are as follows: Step 5.1: Using ion etching method to study the energy level matching in quasi-two-dimensional perovskite by studying the electronic energy level of different surface depths of quasi-two-dimensional perovskite; Step 5.2: Prepare single-charge transport devices and analyze the mobility of vertical growth perovskite thin film and control film using space charge limited current model, to study the effect of charge transport in quasi-two-dimensional perovskite.

5. The method of claim 1, wherein the quasi-two-dimensional blue perovskite LED is grown on a substrate, and the substrate is selected from the group consisting of GaAs, GaP, GaN, InP, InAs, InN, AlAs, AlP, AlN, Si, Ge, and combinations thereof. The specific steps of step 6 are as follows: Step 6.1: Perform steady-state and transient luminescence spectrum testing on perovskite thin film grown in different ways, compare the luminescence intensity, luminescence peak position, and luminescence lifetime characteristics, study the exciton radiation and non-radiative recombination process of perovskite thin film, and analyze the exciton lifetime in quasi-two-dimensional perovskite; Step 6.2: Modify the wettability of the lower interface buffer layer of perovskite to further adjust the grain boundary size of perovskite to enhance exciton radiative recombination, and to study the exciton radiative recombination mode of vertical growth thin film; Step 6.3: According to the material properties, use appropriate blue light device preparation process, including selecting different P-type semiconductor and N-type semiconductor materials as hole and electron transport layers, respectively, to balance the hole and electron transport ability of the device, and to broaden the light emitting area.

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