Regulation and control research method for crystal orientation mechanism of quasi-two-dimensional perovskite blue light LED

Abstract

The invention discloses a crystal orientation mechanism regulation and control research method of a quasi-two-dimensional perovskite blue light LED, and belongs to the technical field of display.The method comprises the steps that firstly, a theoretical model of quasi-two-dimensional blue light perovskite vertical growth is established, a theoretical basis is constructed, and then through experiments, the crystal orientation mechanism of the quasi-two-dimensional blue light LED is obtained; different substrate and anti-solvent temperatures, a substrate assembly process and the like are analyzed to find the influence of different film forming processes on the crystal orientation of the quasi-two-dimensional blue-light perovskite, and the problem that the substrate and anti-solvent temperatures hinder exciton radiation recombination of the quasi-two-dimensional blue-light perovskite light-emitting diode is solved. Finally, a more suitable process is selected by analyzing the influence of different crystal orientations on the performance of the blue light PeLEDs, and a high-performance blue light PeLEDs device is prepared. According to the method, complete experiments are carried out on the influence of different crystal orientations of quasi-two-dimensional blue light perovskite under different conditions, structures and processes and the influence of different crystal orientations on the performance of the quasi-two-dimensional blue light PeLEDs; and a blue light PeLEDs device is developed.

Description

Technical Field

[0001] The present invention belongs to the field of display technology, and in particular relates to a method for studying the regulation of the crystal orientation mechanism of a quasi-two-dimensional perovskite blue light emitting diode (LED). Background Art

[0002] The research and development of blue light-emitting diodes has been very difficult. In the early days, although red and green LEDs had been successfully commercialized, the manufacture of blue LEDs has always been a problem. It was not until the 1990s that Japanese scientist Shuji Nakamura successfully manufactured high-brightness blue LEDs by using gallium nitride (GaN) materials while working at Nichia Chemical Corporation. Blue perovskite light-emitting diodes (PeLEDs) are the core technical bottleneck for the rapid development of perovskite full-color display and white light lighting technology. Quasi-two-dimensional perovskites can achieve blue light emission by utilizing layer number regulation and quantum confinement effects, and can also significantly improve the stability of film layers and devices with the help of their hydrophobic organic ligands, and have become a research hotspot in the field of perovskites.

[0003] Quasi-two-dimensional blue perovskites have gradually been used in the preparation of sky-blue PeLEDs since 2016. However, the following will explain three different structures of perovskites. Three-dimensional (3D) perovskites are formed by the alternating combination of organic and inorganic components in three-dimensional space, two-dimensional (2D) perovskites are lamellar structures formed by the alternation of two components, and quasi-two-dimentional (Q2D) perovskites are a mixed structure of the two types of perovskites, that is, three-dimensional perovskites of different sizes are wrapped by large-sized organic shells. At present, the research on perovskite blue light-emitting materials and blue light-emitting diodes is still lagging behind. Pure 2D perovskites have poor transmission properties, and 3D perovskites are still unstable. Summary of the invention

[0004] The present invention proposes a research method for regulating the crystal orientation mechanism of a quasi-two-dimensional perovskite blue light emitting diode, so as to solve the problem that the research on perovskite blue light emitting materials and blue light emitting diodes in the prior art is still lagging behind, pure 2D perovskite has poor transmission characteristics, and 3D perovskite still has the problem of instability.

[0005] The technical solution adopted by the present invention is as follows: A method for studying the crystal orientation mechanism regulation of a quasi-two-dimensional perovskite blue light emitting diode comprises the following steps: Step 1: Establish a perovskite crystal growth process model, analyze the fine structure and morphology characteristics of quasi-two-dimensional blue perovskite, and study the theoretical model and internal mechanism of film-forming process regulating the growth of quasi-two-dimensional blue perovskite crystals; Step 2: By adjusting the substrate and anti-solvent temperature conditions, explore the effect of the interaction between organic long-chain cations and three-dimensional crystals on the orientation of quasi-two-dimensional blue light perovskite crystals; Step 3: Modify the substrate layer by self-assembly and wetting methods to explore the influence of different substrate surface properties on the growth orientation of quasi-two-dimensional blue light perovskite; Step 4: Combine theoretical simulation calculations to change the different orientation parameters of the quasi-two-dimensional blue light perovskite material crystallization to verify the growth mechanism of the quasi-two-dimensional blue light perovskite crystal orientation; Step 5: Since some physical properties of the quasi-two-dimensional blue perovskite film will change when the crystal quality and crystal orientation of the quasi-two-dimensional blue perovskite change, the changes in the crystal structure, defect state, charge transport, and photophysical characteristics of the quasi-two-dimensional blue perovskite film caused by the change in crystal orientation under various growth conditions are explored experimentally; Step 6: By testing the change rules of quasi-two-dimensional blue light perovskite crystals caused by growth conditions, screen out quasi-two-dimensional blue light perovskite structures that have a positive effect on device performance improvement, and establish a correlation with the efficiency of the corresponding blue light device; Step 7: Regulate the preparation process of vertical growth of quasi-two-dimensional blue perovskite through interface regulation and process optimization, regulate the vertically oriented crystal growth of quasi-two-dimensional blue perovskite, promote carrier transmission at the interface of the functional layer and in the light-emitting layer, and develop blue light PeLEDs devices.

[0006] Preferably, the specific steps of step 1 are as follows: Step 1.1: Establish and improve the theoretical model of blue light devices based on quasi-two-dimensional blue light perovskite with vertical crystal growth, and use the island growth model of polycrystalline thin film crystallization, the perovskite interface growth model and the carrier transport model to establish the kinetic model of vertical growth of inorganic crystals in quasi-two-dimensional blue light perovskite; Step 1.2: Simulate the effect of substrate temperature on the crystal orientation of quasi-2D blue perovskite films in different film forming processes; Step 1.3: Study the crystal growth mechanism of quasi-two-dimensional blue light perovskite and the intrinsic laws of crystal growth thermodynamics. Most of the organic ligands that form quasi-two-dimensional blue light perovskite contain saturated long chains, which limit the charge transfer between inorganic skeletons and construct a crystal orientation perpendicular to the substrate.

[0007] Preferably, the specific steps of step 2 are as follows: Step 2.1: Using PbBr2, MABr, CsBr, and PEABr as raw materials, dissolving the raw materials in N,N-dimethylacetamide solvent, dimethyl sulfoxide solvent, or a mixed solvent of the two according to different ratios; Step 2.2: The preheating temperature of the substrate is set gradually from room temperature to 180°C, with each 5°C as a sample. For the quasi-two-dimensional blue light perovskite film, the crystallization state and crystal orientation of the quasi-two-dimensional blue light perovskite film at different preheating temperatures are characterized by scanning electron microscopy and X-ray diffraction technology; Step 2.3: Use hot injection of anti-solvent to study the effect of the crystal orientation of quasi-two-dimensional blue light perovskite. First, determine the boiling point of different anti-solvents to be used, and set the temperature of the anti-solvent in a gradient from room temperature to boiling point, with each interval of 5°C as a sample. At the same time, for the prepared quasi-two-dimensional blue light perovskite film, use scanning electron microscopy and X-ray diffraction technology to characterize the crystallization state and crystal orientation of the quasi-two-dimensional blue light perovskite at different preheating temperatures.

[0008] Preferably, the specific steps of step 3 are as follows: Step 3.1: Use a PIN-type device structure to analyze and preview the effect of the transport layer interface on the crystal orientation of the quasi-two-dimensional blue light perovskite growth; Step 3.2: Use oxides, small molecules, and polymers as hole transport layers, respectively, analyze the effects of different hole transport layer film wettability, functional groups, roughness, and microstructure on crystal orientation, and determine the conditions for obtaining vertical growth.

[0009] Preferably, the specific steps of step 5 are as follows: Step 5.1: Use ion etching to study the energy level matching in the quasi-two-dimensional blue perovskite by studying the electronic energy levels at different surface depths of the quasi-two-dimensional blue perovskite; Step 5.2: Prepare a single charge transfer device and use the space charge limited current model to analyze the mobility of the vertically grown quasi-two-dimensional blue light perovskite film and the control film to study the impact of charge transfer in the quasi-two-dimensional blue light perovskite.

[0010] Preferably, the specific steps of step 6 are as follows: Step 6.1: Conduct steady-state and transient luminescence spectrum tests on the grown quasi-two-dimensional blue perovskite film, and study the exciton radiation and non-radiative recombination process of the quasi-two-dimensional blue perovskite film by comparing the luminescence intensity, luminescence peak position, and luminescence lifetime characteristics, and analyze the exciton lifetime in the quasi-two-dimensional blue perovskite; Step 6.2: Modify the wettability of the lower interface buffer layer of the quasi-two-dimensional blue perovskite, and further adjust the grain boundary size of the quasi-two-dimensional blue perovskite to enhance the exciton radiative recombination of the quasi-two-dimensional blue perovskite, so as to study the exciton radiative recombination mode of the vertically grown film; Step 6.3: Adopt appropriate blue light device preparation process according to the characteristics of quasi-two-dimensional blue light perovskite material, including screening different P-type semiconductor and N-type semiconductor materials as hole and electron transport layers respectively, to balance the hole-electron transport capacity of the device and broaden the light-emitting area.

[0011] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 A flowchart of the present application is shown below; Figure 2 This is a diagram of the blue light PeLEDs device structure of this application; Figure 3 This is a schematic diagram of the structure of the quasi-two-dimensional blue light perovskite in this application. DETAILED DESCRIPTION

[0013] All features disclosed in this specification, or steps in all methods or processes disclosed, except mutually exclusive features and / or steps, can be combined in any manner.

[0014] Combine the following Figures 1 to 3 The present invention is described in detail.

[0015] Example 1 A research method for regulating the crystal orientation mechanism of quasi-two-dimensional perovskite blue light LEDs, such as Figure 1 , Figure 2 , Figure 3 As shown, the following steps are included: Step 1: Establish a perovskite crystal growth process model, analyze the fine structure and morphology characteristics of quasi-two-dimensional blue perovskite, and study the theoretical model and internal mechanism of film-forming process regulation of quasi-two-dimensional blue perovskite crystal growth. The specific steps of step 1 are as follows: Step 1.1: Establish and improve the theoretical model of blue light devices based on quasi-two-dimensional blue light perovskite with vertical crystal growth, and use the island growth model of polycrystalline thin film crystallization, the perovskite interface growth model and the carrier transport model to establish the kinetic model of vertical growth of inorganic crystals in quasi-two-dimensional blue light perovskite; Step 1.2: Simulate the effect of substrate temperature on the crystal orientation of quasi-2D blue perovskite films in different film forming processes; Step 1.3: Study the growth mechanism of quasi-two-dimensional blue perovskite crystals and the intrinsic laws of crystal growth thermodynamics. Most of the organic ligands that form quasi-two-dimensional blue perovskites contain saturated long chains, which restrict the charge transfer between inorganic skeletons and construct a crystal orientation perpendicular to the substrate. Step 2: By adjusting the substrate and anti-solvent temperature conditions, the effect of the interaction between organic long-chain cations and three-dimensional crystals on the orientation of quasi-two-dimensional blue light perovskite crystals is explored. The specific steps of step 2 are as follows: Step 2.1: Using PbBr2, MABr, CsBr, and PEABr as raw materials, dissolving the raw materials in N,N-dimethylacetamide solvent, dimethyl sulfoxide solvent, or a mixed solvent of the two according to different ratios; Step 2.2: The preheating temperature of the substrate is set gradually from room temperature to 180°C, with each 5°C as a sample. For the quasi-two-dimensional blue light perovskite film, the crystallization state and crystal orientation of the quasi-two-dimensional blue light perovskite film at different preheating temperatures are characterized by scanning electron microscopy and X-ray diffraction technology; Step 2.3: The effect of hot injection of anti-solvent on the crystal orientation of quasi-two-dimensional blue light perovskite was studied. First, the boiling points of different anti-solvents to be used were determined, and the temperature of the anti-solvent was set in a gradient from room temperature to boiling point, with each interval of 5°C as a sample. At the same time, for the prepared quasi-two-dimensional blue light perovskite film, the crystal state and crystal orientation of the quasi-two-dimensional blue light perovskite at different preheating temperatures were characterized by scanning electron microscopy and X-ray diffraction technology; In step 2 of the present application, when exploring the effect of different substrate temperatures on the crystal orientation of quasi-two-dimensional perovskite, the substrate temperature and anti-solvent temperature are set at equal intervals: the substrate temperature is from room temperature to 180°C, and the anti-solvent temperature is from room temperature to boiling point, both with a progressive value of 5°C. In addition, high-performance scanning electron microscopy and X-ray diffraction technology are used to clearly characterize the crystallization and crystal orientation of quasi-two-dimensional perovskite at different preheating temperatures and anti-solvent temperatures. The experimental data not only includes the crystal state at each theoretically feasible temperature, but also uses advanced equipment and technology to increase the accuracy of the experiment and the convenience of observation.

[0016] Step 3: Use self-assembly and wetting methods to modify the substrate layer and explore the influence of different substrate surface properties on the growth orientation of quasi-two-dimensional blue light perovskite. The specific steps of step 3 are as follows: Step 3.1: Use a PIN-type device structure to analyze and preview the effect of the transport layer interface on the crystal orientation of the quasi-two-dimensional blue light perovskite growth; Step 3.2: Using oxides, small molecules, and polymers as hole transport layers, respectively, analyzing the effects of different hole transport layer film wettability, functional groups, roughness, and microstructure on crystal orientation, and determining the conditions for obtaining vertical growth; Step 4: Combine theoretical simulation calculations to change the different orientation parameters of the quasi-two-dimensional blue light perovskite material crystallization to verify the growth mechanism of the quasi-two-dimensional blue light perovskite crystal orientation; Step 5: Since some physical properties of the quasi-two-dimensional blue perovskite film will change when the crystal quality and crystal orientation of the quasi-two-dimensional blue perovskite change, the effects of various growth conditions on the crystal structure, defect state, charge transfer, and photophysical characteristics of the quasi-two-dimensional blue perovskite will be experimentally explored. The specific steps of step 5 are as follows: Step 5.1: Use ion etching to study the energy level matching in the quasi-two-dimensional blue perovskite by studying the electronic energy levels at different surface depths of the quasi-two-dimensional blue perovskite; Step 5.2: Prepare a single charge transfer device and use the space charge limited current model to analyze the mobility of the vertically grown quasi-two-dimensional blue perovskite film and the control film to study the effect of charge transfer in the quasi-two-dimensional blue perovskite; In step 5 of the present application, ion etching is used to fabricate a single charge transfer device, and a space charge limited current model is used. The electron energy levels at 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 to provide a reference for the subsequent enhancement of exciton radiative recombination.

[0017] Step 6: By testing 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 has a positive effect on improving the device performance is screened out, and a correlation is established with the efficiency of the corresponding blue light device. The specific steps of step 6 are as follows: Step 6.1: Conduct steady-state and transient luminescence spectrum tests on the grown quasi-two-dimensional blue perovskite film, and study the exciton radiation and non-radiative recombination process of the quasi-two-dimensional blue perovskite film by comparing the luminescence intensity, luminescence peak position, and luminescence lifetime characteristics, and analyze the exciton lifetime in the quasi-two-dimensional blue perovskite; Step 6.2: Modify the wettability of the lower interface buffer layer of the quasi-two-dimensional blue perovskite, and further adjust the grain boundary size of the quasi-two-dimensional blue perovskite to enhance the exciton radiative recombination of the quasi-two-dimensional blue perovskite, so as to study the exciton radiative recombination mode of the vertically grown film; Step 6.3: Adopt appropriate blue light device preparation process according to the characteristics of quasi-two-dimensional blue light perovskite materials, including screening different P-type semiconductor and N-type semiconductor materials as hole and electron transport layers, respectively, to balance the hole-electron transport capacity of the device and broaden the light-emitting area; In step 6.1 of the present application, steady-state and transient luminescence spectrum tests are introduced on the grown quasi-two-dimensional blue light perovskite film, and the exciton lifetime in the quasi-two-dimensional blue light perovskite is analyzed.

[0018] In order to solve the problem that temperature hinders the exciton radiative recombination of the quasi-two-dimensional blue light perovskite light-emitting diode, step 6.2 of the present application improves the quasi-two-dimensional blue light perovskite structure, modifies the wettability of the lower interface buffer layer of the quasi-two-dimensional blue light perovskite, and enhances the exciton radiative recombination of the quasi-two-dimensional blue light perovskite.

[0019] Step 6.3 of the present application adjusts the hole and electron transport layers to further balance the hole-electron transport capacity of the device, broaden the light-emitting area, and improve the electron transport capacity and light-emitting performance of the blue light PeLEDs device.

[0020] Step 7: Regulate the preparation process of vertical growth of quasi-two-dimensional blue perovskite through interface regulation and process optimization, regulate the vertically oriented crystal growth of quasi-two-dimensional blue perovskite, promote carrier transmission at the interface of the functional layer and in the light-emitting layer, and develop blue light PeLEDs devices.

[0021] In this embodiment, the present application deeply analyzes the influence of different conditions on crystal growth during the crystallization process, obtains the optimal solution for the vertical growth of quasi-two-dimensional blue light perovskite crystals, and solves 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 to quasi-two-dimensional blue light perovskite crystal conversion stage, resulting in the formation of larger grain boundaries in the quasi-two-dimensional blue light perovskite crystal, thereby hindering the exciton radiation recombination of the quasi-two-dimensional blue light perovskite light-emitting diode by optimizing the experimental technology and methods and improving the manufacturing process. Finally, a highly efficient and stable blue light PeLEDs device is developed.

[0022] This application establishes a theoretical model of vertical growth of quasi-two-dimensional blue perovskite based on the theoretical basis of perfecting the quasi-two-dimensional blue PeLEDs based on the thermodynamic analysis of crystal growth of multi-component system, the nucleation principle and kinetic model of the crystal growth process, and provides theoretical support for the preparation and optimization of quasi-two-dimensional blue perovskite crystal films. Specifically: (1) According to the crystal orientation, dimension and material composition in the quasi-two-dimensional blue perovskite film, combined with its film forming process, summarize the factors affecting the optical and electrical properties of the quasi-two-dimensional blue perovskite film; (2) Establish the functional layer parameter simulation of the optical and electrical properties of the substrate, transparent electrode material, main material, quasi-two-dimensional blue perovskite material, charge transport material, metal electrode material, and packaging material, and the film thickness; (3) Study the optical structure and theoretical simulation of blue PeLEDs, and establish the device optical model of visible light emission efficiency and external quantum efficiency.

[0023] The following work was done to study the effects of different film-forming processes on the crystallization orientation of quasi-two-dimensional blue perovskites: (1) The introduction method, ratio concentration, and annealing temperature of organic long-chain amine salts were explored, and the control factors for the formation of different quasi-two-dimensional blue perovskite inorganic skeleton layers in the film were analyzed; (2) By adjusting the substrate temperature and antisolvent temperature, the influence of heat changes during the crystallization of quasi-two-dimensional blue perovskites on the growth orientation of quasi-two-dimensional blue perovskites was analyzed; (3) The substrate layer was modified by self-assembly and wetting methods to explore the influence of different substrate surface characteristics on the growth orientation of quasi-two-dimensional blue perovskites; (4) Combined with theoretical simulation calculations, the different orientation parameters of material crystallization were changed to verify the growth mechanism of quasi-two-dimensional blue perovskite crystallization orientation. Through screening, the temperature and substrate of the quasi-two-dimensional blue perovskite with the highest efficiency were obtained. Finally, different charge injection methods were tried to prepare blue light PeLEDs using quasi-two-dimensional blue perovskites as the light-emitting layer, the performance of blue light devices was characterized, and the mechanism of the influence of the crystallization orientation of quasi-two-dimensional blue perovskite films on device efficiency was analyzed to prepare blue light PeLEDs.

[0024] The above is only a preferred embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be thought of by a person skilled in the art within the technical scope disclosed by the present invention without creative work should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope defined in the claims.

Claims

1. A method for regulating the crystal orientation mechanism of a quasi-two-dimensional perovskite blue light emitting diode, comprising the following steps: Step 1: Establish a perovskite crystal growth process model, analyze the fine structure and morphology characteristics of quasi-two-dimensional blue perovskite, and study the theoretical model and internal mechanism of film-forming process regulating the growth of quasi-two-dimensional blue perovskite crystals; Step 2: By adjusting the substrate and anti-solvent temperature conditions, explore the effect of the interaction between organic long-chain cations and three-dimensional crystals on the orientation of quasi-two-dimensional blue light perovskite crystals; Step 3: Modify the substrate layer by self-assembly and wetting methods to explore the influence of different substrate surface properties on the growth orientation of quasi-two-dimensional blue light perovskite; Step 4: Combine theoretical simulation calculations to change the different orientation parameters of the quasi-two-dimensional blue light perovskite material crystallization to verify the growth mechanism of the quasi-two-dimensional blue light perovskite crystal orientation; Step 5: Since some physical properties of the quasi-two-dimensional blue perovskite film will change when the crystal quality and crystal orientation of the quasi-two-dimensional blue perovskite change, the changes in the crystal structure, defect state, charge transport, and photophysical characteristics of the quasi-two-dimensional blue perovskite film caused by the change in crystal orientation under various growth conditions are explored experimentally; Step 6: By testing the change rules of quasi-two-dimensional blue light perovskite crystals caused by growth conditions, screen out quasi-two-dimensional blue light perovskite structures that have a positive effect on device performance improvement, and establish a correlation with the efficiency of the corresponding blue light device; Step 7: Regulate the preparation process of vertical growth of quasi-two-dimensional blue perovskite through interface regulation and process optimization, regulate the vertically oriented crystal growth of quasi-two-dimensional blue perovskite, promote carrier transmission at the interface of the functional layer and in the light-emitting layer, and develop blue light PeLEDs devices.

2. The method for controlling the crystal orientation mechanism of a quasi-two-dimensional perovskite blue light LED according to claim 1, characterized in that: The specific steps of step 1 are as follows: Step 1.1: Establish and improve the theoretical model of blue light devices based on quasi-two-dimensional blue light perovskite with vertical crystal growth, and use the island growth model of polycrystalline thin film crystallization, the perovskite interface growth model and the carrier transport model to establish the kinetic model of vertical growth of inorganic crystals in quasi-two-dimensional blue light perovskite; Step 1.2: Simulate the effect of substrate temperature on the crystal orientation of quasi-2D blue perovskite films in different film forming processes; Step 1.3: Study the crystal growth mechanism of quasi-two-dimensional blue light perovskite and the intrinsic laws of crystal growth thermodynamics. Most of the organic ligands that form quasi-two-dimensional blue light perovskite contain saturated long chains, which limit the charge transfer between inorganic skeletons and construct a crystal orientation perpendicular to the substrate.

3. The method for controlling the crystal orientation mechanism of a quasi-two-dimensional perovskite blue light LED according to claim 1, characterized in that: The specific steps of step 2 are as follows: Step 2.1: Using PbBr2, MABr, CsBr, and PEABr as raw materials, dissolving the raw materials in N,N-dimethylacetamide solvent, dimethyl sulfoxide solvent, or a mixed solvent of the two according to different ratios; Step 2.2: The preheating temperature of the substrate is set gradually from room temperature to 180°C, with each 5°C as a sample. For the quasi-two-dimensional blue light perovskite film, the crystallization state and crystal orientation of the quasi-two-dimensional blue light perovskite film at different preheating temperatures are characterized by scanning electron microscopy and X-ray diffraction technology; Step 2.3: Use hot injection of anti-solvent to study the effect of the crystal orientation of quasi-two-dimensional blue light perovskite. First, determine the boiling point of different anti-solvents to be used, and set the temperature of the anti-solvent in a gradient from room temperature to boiling point, with each interval of 5°C as a sample. At the same time, for the prepared quasi-two-dimensional blue light perovskite film, use scanning electron microscopy and X-ray diffraction technology to characterize the crystallization state and crystal orientation of the quasi-two-dimensional blue light perovskite at different preheating temperatures.

4. The method for controlling the crystal orientation mechanism of a quasi-two-dimensional perovskite blue light LED according to claim 1, characterized in that: The specific steps of step 3 are as follows: Step 3.1: Use a PIN-type device structure to analyze and preview the effect of the transport layer interface on the crystal orientation of the quasi-two-dimensional blue light perovskite growth; Step 3.2: Use oxides, small molecules, and polymers as hole transport layers, respectively, analyze the effects of different hole transport layer film wettability, functional groups, roughness, and microstructure on crystal orientation, and determine the conditions for obtaining vertical growth.

5. The method for controlling the crystal orientation mechanism of a quasi-two-dimensional perovskite blue light LED according to claim 1, characterized in that: The specific steps of step 5 are as follows: Step 5.1: Use ion etching to study the energy level matching in the quasi-two-dimensional blue perovskite by studying the electronic energy levels at different surface depths of the quasi-two-dimensional blue perovskite; Step 5.2: Prepare a single charge transfer device and use the space charge limited current model to analyze the mobility of the vertically grown quasi-two-dimensional blue light perovskite film and the control film to study the impact of charge transfer in the quasi-two-dimensional blue light perovskite.

6. The method for controlling the crystal orientation mechanism of a quasi-two-dimensional perovskite blue light LED according to claim 1, characterized in that: The specific steps of step 6 are as follows: Step 6.1: Conduct steady-state and transient luminescence spectrum tests on the grown quasi-two-dimensional blue perovskite film, and study the exciton radiation and non-radiative recombination process of the quasi-two-dimensional blue perovskite film by comparing the luminescence intensity, luminescence peak position, and luminescence lifetime characteristics, and analyze the exciton lifetime in the quasi-two-dimensional blue perovskite; Step 6.2: Modify the wettability of the lower interface buffer layer of the quasi-two-dimensional blue perovskite, and further adjust the grain boundary size of the quasi-two-dimensional blue perovskite to enhance the exciton radiative recombination of the quasi-two-dimensional blue perovskite, so as to study the exciton radiative recombination mode of the vertically grown film; Step 6.3: Adopt appropriate blue light device preparation process according to the characteristics of quasi-two-dimensional blue light perovskite material, including screening different P-type semiconductor and N-type semiconductor materials as hole and electron transport layers respectively, to balance the hole-electron transport capacity of the device and broaden the light-emitting area.

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