A perovskite polycrystalline thin film spatial selective passivation device and method

Abstract

The present invention relates to the technical field of perovskite crystal surface treatment, and particularly to a spatial selective passivation device and method for perovskite polycrystalline thin films. The device includes a laser, a beam adjustment unit, and a three-dimensional moving platform; the beam adjustment unit includes a first aperture diaphragm, an attenuator, a second aperture diaphragm, a chopper, and a cylindrical lens arranged coaxially in sequence; the first and second aperture diaphragms are arranged in the output direction of the laser; the chopper is used to modulate the laser waveform to form a periodically distributed light field; the laser emits a laser beam, which enters the first aperture diaphragm for collimation, and then the laser power is controlled by the attenuator. After being collimated by the second aperture diaphragm, the waveform is modulated by the chopper, and then focused on the perovskite polycrystalline thin film sample through the cylindrical lens to achieve surface passivation. The advantages are as follows: the chopper regulates the laser waveform, generates the laser pulse beat frequency effect, produces a periodically distributed light field on the thin film surface, and realizes the passivation of two typical deep and shallow energy level defects in perovskite.

Description

Technical Field

[0001] The present invention relates to the technical field of perovskite crystal surface treatment, and particularly relates to a device and method for spatially selective passivation of perovskite polycrystalline thin films. Background Art

[0002] The novel organic / inorganic hybrid semiconductor material - perovskite AMX3 (A = organic or inorganic cation, M = metal cation, X = halogen anion) has attracted much attention in the field of optoelectronic devices due to its excellent optophysical properties, such as high light absorption coefficient, long carrier transport length, long carrier lifetime, and high carrier mobility, showing great application potential in optoelectronic devices such as solar cells, light-emitting diodes (LEDs), and photodetectors. Especially perovskite polycrystalline thin films, as an important form of perovskite materials, have the advantages of short preparation cycle and large-area preparation compared with perovskite single crystals, which are more conducive to the commercial application of perovskite materials. Therefore, they are excellent materials for preparing optoelectronic devices.

[0003] Although perovskite polycrystalline thin films have many advantages, in practical applications, there are often a large number of defect states on their surfaces and grain boundaries. These defect states can capture carriers, leading to an increase in non-radiative recombination, thereby reducing the performance of optoelectronic devices, such as reducing the photoelectric conversion efficiency of solar cells and the luminous efficiency of LEDs. Therefore, effective passivation treatment of perovskite polycrystalline thin films to reduce defect states on the surface and grain boundaries is crucial for improving the performance of perovskite optoelectronic devices.

[0004] So far, the methods for passivating perovskite polycrystalline thin films mainly include chemical passivation, physical passivation, high-energy passivation, and field-effect passivation. Chemical passivation is usually achieved by introducing chemical reagents on the perovskite surface, but this method may introduce impurities and affect the optoelectronic properties of perovskite. Physical passivation methods treat the perovskite surface by physical means, such as laser passivation, which has the advantages of pollution-free, high efficiency, and precise control of the passivation area compared with other methods. However, due to the different sensitivities of typical deep-level defects (uncoordinated lead atoms) and typical shallow-level defects (halogen vacancies) in perovskite to laser, it is a technical difficulty to passivate these two types of defects simultaneously. Based on the limitations of the existing technology, it is difficult to meet the requirements of the development of perovskite optoelectronic devices in terms of high performance and multifunctionalization. Therefore, there is an urgent need to develop a device and method for passivating perovskite polycrystalline thin films that can achieve spatially selective multifunctional passivation. Summary of the Invention

[0005] In order to solve the above problems, the present invention provides a device and method for spatially selective passivation of perovskite polycrystalline thin films.

[0006] The first object of the present invention is to provide a spatial selective passivation device for perovskite polycrystalline thin films, comprising a laser, a beam adjustment unit and a three-dimensional moving platform; the laser and the beam adjustment unit are coaxially arranged; the three-dimensional moving platform drives the perovskite polycrystalline thin film sample to move three-dimensionally; the beam adjustment unit includes a first aperture diaphragm, an attenuator, a second aperture diaphragm, a chopper and a cylindrical lens which are coaxially arranged in sequence; the first aperture diaphragm and the second aperture diaphragm are arranged in the outgoing direction of the laser for modulating the laser beam emitted by the laser, collimating the laser beam and restricting the beam diameter; the attenuator is used to control the laser power; the chopper is used to modulate the laser waveform and form a periodically distributed light field by using the beat frequency effect generated by laser pulses; the cylindrical lens is used to focus the laser beam and magnify the scanning range from a point to a plane;

[0007] The laser emits a laser beam, which enters the first aperture diaphragm for collimation and then the laser power is controlled by the attenuator. After being collimated for the second time by the second aperture diaphragm, the waveform is modulated by the chopper to generate a beat frequency effect, and then is focused onto the perovskite polycrystalline thin film sample on the three-dimensional moving platform through the cylindrical lens, realizing the passivation of the surface of the perovskite polycrystalline thin film sample.

[0008] Preferably, the wavelength band of the laser beam emitted by the laser is the infrared light band or the visible light band.

[0009] Preferably, the beam adjustment unit is a rotatable unit.

[0010] Preferably, the laser beam emitted by the laser is femtosecond laser, picosecond laser or nanosecond laser.

[0011] The second object of the present invention is to provide a spatial selective passivation method for perovskite polycrystalline thin films, which uses a spatial selective passivation device for perovskite polycrystalline thin films for passivation, and comprises the following steps:

[0012] S1. Set the laser power emitted by the laser, and adjust the z-axis of the three-dimensional moving platform at the laser power to determine the focal plane and the defocus distance; after adjusting the defocus distance, place the perovskite polycrystalline thin film sample at a defocus position 500-1000 μm behind the focal plane;

[0013] S2. Set the burn threshold of the laser beam focused on the surface of the perovskite polycrystalline thin film sample to 20-50 mW; after determining the defocus distance, reduce the laser power to the burn threshold;

[0014] S3. Set the initial chopper frequency; adjust the moving speed of the three-dimensional moving platform under the conditions of the defocus distance, the burn threshold and the initial chopper frequency;

[0015] S4. Increase the chopper frequency to the repetition frequency of the laser, and determine the chopper frequency that can preserve the surface of the perovskite thin film; utilize the beat frequency effect generated by the laser pulse at an appropriate chopper frequency to complete the spatial selective passivation of the perovskite polycrystalline thin film. Preferably, the laser emits a femtosecond laser beam; the burn threshold of the femtosecond laser beam is 20 - 50 mW.

[0016] Preferably, the defocus distance is 500 - 1000 μm; the moving rate of the three-dimensional moving platform is 0.001 - 3 mm / s; the chopper frequency is 910 Hz - 990 Hz.

[0017] Preferably, the laser emits a femtosecond laser beam with a power value of 4 mW; the defocus distance is 500 μm; the moving rate of the three-dimensional moving platform is 0.5 mm / s; the chopper frequency is 950 Hz.

[0018] The third object of the present invention is to provide a perovskite polycrystalline thin film prepared by a method for spatial selective passivation of a perovskite polycrystalline thin film, and the perovskite crystal thin film is a three-dimensional perovskite polycrystalline thin film of the ABX3 type, a two-dimensional perovskite polycrystalline thin film of the A2BX4 type, or a composite perovskite polycrystalline thin film;

[0019] In the three-dimensional perovskite polycrystalline thin film of the ABX3 type, A is any one of cesium, methylamine, or formamidine, or a doping of two or more of them in any proportion; B in the three-dimensional perovskite polycrystalline thin film of the ABX3 type is lead, tin, or a doping of lead and tin in any proportion; X in the three-dimensional perovskite polycrystalline thin film of the ABX3 type is any one of bromine, iodine, chlorine, or fluorine, or a doping of two or more of them in any proportion;

[0020] In the two-dimensional perovskite polycrystalline thin film of the A2BX4 type, A is any one of phenethylamine, phenylpropylamine, phenylbutylamine, or butylamine, or a doping of two or more of them in any proportion; B in the two-dimensional perovskite polycrystalline thin film of the A2BX4 type is lead, tin, or a doping of lead and tin in any proportion; X in the two-dimensional perovskite polycrystalline thin film of the A2BX4 type is any one of bromine, iodine, chlorine, or fluorine, or a doping of two or more of them in any proportion.

[0021] The fourth object of the present invention is to provide an LED device, which sequentially includes a cathode, an electron transport layer, a photosensitive layer, a hole transport layer, and an anode from bottom to top; the material of the photosensitive layer is a perovskite polycrystalline thin film.

[0022] Compared with the prior art, the present invention can achieve the following beneficial effects:

[0023] A chopper is provided in the perovskite polycrystalline thin film spatial selective passivation device of the present invention. The chopper is used to regulate the femtosecond laser waveform, generate a periodically distributed optical field on the surface of the perovskite thin film, and then achieve the passivation of two typical deep-level defects and shallow-level defects in the perovskite. By adjusting the chopper frequency, a suitable periodically distributed optical field with strong and weak intensity is generated on the perovskite surface, realizing the spatial selective passivation of the perovskite polycrystalline thin film surface, which is beneficial to improving the performance of related perovskite optoelectronic devices. Description of the Drawings

[0024] Figure 1 FIG. is a schematic structural diagram of a perovskite polycrystalline thin film spatial selective multi-functional passivation device provided according to an embodiment of the present invention.

[0025] Figure 2 FIG. is a schematic flow chart of a perovskite polycrystalline thin film spatial selective multi-functional passivation method provided according to an embodiment of the present invention.

[0026] Figure 3 FIG. is the temperature-dependent photoluminescence (PL) and X-ray Photoelectron Spectroscopy (XPS) results of the perovskite polycrystalline thin film spatial selective multi-functional passivation and the control group provided according to an embodiment of the present invention; the temperature-dependent PL is used to measure the formation energy of halogen vacancy defects, and XPS is used to measure the degree of passivation of uncoordinated lead atoms.

[0027] Figure 4 FIG. is the temperature-dependent PL and XPS results at different powers without spatial selective multi-functional passivation.

[0028] Figure 5 FIG. is the room temperature time-resolved photoluminescence emission (TRPL) spectra of the perovskite polycrystalline thin film before and after spatial selective multi-functional passivation provided according to an embodiment of the present invention.

[0029] Figure 6 FIG. is the Scanning Electron Microscope (SEM) and Energy Dispersive Spectroscopy (EDS) diagrams of the perovskite polycrystalline thin film before and after spatial selective multi-functional passivation provided according to an embodiment of the present invention.

[0030] Figure 7 FIG. is a schematic structural diagram of an LED device provided according to an embodiment of the present invention.

[0031] Reference Numerals:

[0032] 1. Laser

[0033] 2. First Aperture Diaphragm

[0034] 3. Attenuator;

[0035] 4. Second aperture diaphragm;

[0036] 5. Chopper;

[0037] 6. Cylindrical lens;

[0038] 7. Sample

[0039] 8. Three-dimensional moving platform;

[0040] 9. Cathode;

[0041] 10. Electron transport layer;

[0042] 11. Photosensitive layer;

[0043] 12. Hole transport layer;

[0044] 13. Anode. Detailed implementation manners

[0045] In the following, embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, the same modules are denoted by the same reference numerals. In the case of the same reference numerals, their names and functions are also the same. Therefore, their detailed descriptions will not be repeated.

[0046] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention.

[0047] Figure 1 The structure of the perovskite polycrystalline thin film spatial selective passivation device of the present invention is shown.

[0048] As Figure 1 shown, the present invention provides a perovskite polycrystalline thin film spatial selective passivation device, including a laser 1, a beam adjustment unit and a three-dimensional moving platform 7;

[0049] The laser 1 is used to emit a laser beam; the laser 1 can be a laser in the infrared light band or the visible light band, and the emitted laser beam can be a femtosecond pulse laser, a picosecond pulse laser or a nanosecond pulse laser; the power of the laser 1 can be adjusted in the range from several milliwatts to several kilowatts, and the wavelength of the laser beam can be 532 nm, 785 nm, 1064 nm.

[0050] The beam adjustment unit is coaxially arranged with the laser 1, and includes a first aperture diaphragm 2, an attenuator 3, a second aperture diaphragm 4, a chopper 5, and a cylindrical lens 6 that are coaxially arranged in sequence; the first aperture diaphragm 2 and the second aperture diaphragm 4 are arranged in the emission direction of the laser 1, and are used to modulate the laser beam emitted by the laser 1, collimate the laser beam, and limit the beam diameter; the attenuator 3 is used to control the laser power; the chopper 5 is used to modulate the laser waveform and form a periodically distributed light field by using the beat frequency effect; the cylindrical lens 6 is used to focus the laser beam and magnify the scanning range from a point to a surface;

[0051] The sample 7 is fixed on the three-dimensional moving platform 8, and the sample 7 is driven by the three-dimensional moving platform 8 to perform three-dimensional movement;

[0052] The femtosecond pulsed laser emitted by the laser 1 enters the optical path collimated by the first aperture diaphragm 2 and the second aperture diaphragm 4, and its power is controlled by the attenuator 3. It is modulated in waveform by the chopper 5, and then focused on the sample 7 by the cylindrical lens 6. The three-dimensional moving platform 8 is used to control the sample position in the x-y-z axial directions.

[0053] The present invention also provides a method for spatially selective passivation of perovskite polycrystalline thin films (the flow chart is as Figure 2 shown), and the above-mentioned device for spatially selective passivation of perovskite polycrystalline thin films is used for passivation, including the following steps:

[0054] S1. Set the laser power emitted by the laser, and adjust the z-axis of the three-dimensional moving platform at the laser power to determine the focal plane and the defocus distance; after adjusting the defocus distance, place the perovskite polycrystalline thin film sample at a defocus position 500-1000 μm behind the focal plane;

[0055] S2. Set the burn threshold of the laser beam focused on the surface of the perovskite polycrystalline thin film sample to 20-50 mW; after determining the defocus distance, reduce the laser power to the burn threshold;

[0056] S3. Set the initial chopper frequency (the typical value of the initial chopper frequency is 0); adjust the moving speed of the three-dimensional moving platform under the above defocus distance, burn threshold, and initial chopper frequency conditions;

[0057] S4. Increase the chopper frequency to the repetition frequency of the laser, and determine the chopper frequency that can preserve the surface of the perovskite thin film; use the beat frequency effect generated by the laser pulse at an appropriate chopper frequency to complete the spatial selective passivation of the perovskite polycrystalline thin film. In a specific embodiment, the laser emits a femtosecond laser beam; the power value of the femtosecond laser beam (repetition frequency 1000 Hz) is 4 mW, the defocus distance is 500 μm, and the moving speed of the three-dimensional moving platform is 0.5 mm / s; the chopper frequency depends on the repetition frequency of the laser source. Taking the femtosecond laser with a repetition frequency of 1000 Hz as an example, its repetition frequency is 910 Hz to 990 Hz; specifically, the chopper frequency is 950 Hz.

[0058] The perovskite polycrystalline thin film prepared by the above passivation method is a three-dimensional perovskite polycrystalline thin film of ABX3 type, a two-dimensional perovskite polycrystalline thin film of A2BX4 type or a composite perovskite polycrystalline thin film;

[0059] In the three-dimensional perovskite polycrystalline thin film of ABX3 type, A is any one of cesium, methylamine or formamidine or a doping of two or more of them in any proportion; B in the three-dimensional perovskite polycrystalline thin film of ABX3 type is lead, tin or a doping of lead and tin in any proportion; X in the three-dimensional perovskite polycrystalline thin film of ABX3 type is any one of bromine, iodine, chlorine or fluorine or a doping of two or more of them in any proportion;

[0060] In the two-dimensional perovskite polycrystalline thin film of A2BX4 type, A is any one of phenethylamine, phenylpropylamine, phenylbutylamine or butylamine or a doping of two or more of them in any proportion; B in the two-dimensional perovskite polycrystalline thin film of A2BX4 type is lead, tin or a doping of lead and tin in any proportion; X in the two-dimensional perovskite polycrystalline thin film of A2BX4 type is any one of bromine, iodine, chlorine or fluorine or a doping of two or more of them in any proportion.

[0061] In a specific embodiment, the perovskite crystal is a three-dimensional perovskite polycrystalline thin film of ABX3 type, where A is methylamine (MA); B is lead (Pb); X is iodine (I).

[0062] Figure 3 Shows the temperature-dependent PL and XPS spectra of the perovskite polycrystalline thin film before and after spatial selective passivation according to the embodiment of the present invention. As Figure 3 shown, the formation energy of iodine vacancies in the perovskite passivated by this method and experimental device increases significantly, and the peak position of the uncoordinated lead atoms disappears, which is of great significance for the preparation of high-performance LEDs.

[0063] Figure 4 Shows the temperature-dependent PL and XPS at different powers without spatial selective passivation. As Figure 4As shown, laser passivation without spatial selectivity cannot simultaneously obtain the optimal iodine vacancy formation energy and the peak position of uncoordinated lead atoms at the same power. The above results further confirm the importance of the spatial selectivity passivation technology of the present invention.

[0064] Figure 5 Fig. shows the transient fluorescence spectra of the perovskite polycrystalline thin film before and after spatial selectivity passivation provided by the embodiment of the present invention. As Figure 5 shown, the perovskite thin film passivated by the present method and experimental device has a longer carrier lifetime, which confirms the passivation effect of the present passivation method on the perovskite polycrystalline thin film.

[0065] In another embodiment of the present invention, the perovskite crystal is a two-dimensional perovskite polycrystalline thin film of the A2BX4 type, where A is any one of organic amines such as phenethylamine (PEA), phenylpropylamine (PPA), phenylbutylamine (PBA), and butylamine (BA), or a doping of two or more elements in any proportion; B is lead, tin, or a doping of lead and tin in any proportion; X is any one of bromine, iodine, chlorine, and fluorine, or a doping of two or more elements in any proportion.

[0066] The doping of positions A, B, and X in the two-dimensional perovskite polycrystalline thin film of the A2BX4 type has the same effect as the doping of positions A, B, and X in the three-dimensional perovskite polycrystalline thin film of the ABX3 type, so it will not be elaborated here.

[0067] In some examples of the present invention, the composite perovskite polycrystalline thin film can be a composite perovskite material such as a three-dimensional perovskite polycrystalline thin film of the ABX3 type doped with semiconductor quantum dots, two-dimensional materials, fullerenes, or carbon nanotubes. The composite perovskite polycrystalline thin film can also be a composite perovskite material such as a two-dimensional perovskite polycrystalline thin film of the A2BX4 type doped with semiconductor quantum dots, two-dimensional materials, fullerenes, or carbon nanotubes.

[0068] Figure 6 Fig. shows the SEM images and EDS images of the perovskite polycrystalline thin film before and after spatial selectivity passivation provided by the embodiment of the present invention. As Figure 6 shown, the iodine element and oxygen element on the surface of the passivated perovskite are periodically distributed. The iodine element content enrichment region is the iodine vacancy concentrated passivation region, and the oxygen element enrichment region is the uncoordinated lead atom passivation region, which confirms that the effect of the present passivation device and passivation method is reliable.

[0069] The above content details the spatial selectivity passivation device and method of the perovskite polycrystalline thin film provided by the embodiment of the present invention; corresponding to the perovskite polycrystalline thin film, the embodiment of the present invention also provides an LED device prepared from the passivated perovskite polycrystalline thin film.

[0070] Figure 7shows the structure of an LED provided according to an embodiment of the present invention. As Figure 7 shown, the LED includes a cathode 9, an electron transport layer 10, a photosensitive layer 11, a hole transport layer 12, and an anode 13; the cathode 9 can be glass ITO, the electron transport layer 10 can be zinc oxide (ZnO), the material of the photosensitive layer 11 is a thin sheet made of the above-mentioned perovskite polycrystalline thin film, the thickness of the thin sheet is about 500 nm, the hole transport layer 12 can be Spiro-ometad, and the anode 13 can be a metal such as aluminum (Al).

[0071] Under the action of an applied voltage, carriers electrons and holes that are directionally transported are generated inside the perovskite crystal and quickly recombine to emit photons; since the electron transport layer 10, the photosensitive layer 11, and the hole transport layer 12 form a consistent gradient in the energy level structure, electrons and holes are directionally transported between the anode 13 and the cathode 9 and radiative recombination luminescence is achieved in the photosensitive layer 11.

[0072] It should be understood that various forms of the processes shown above can be used, steps can be reordered, added, or deleted. For example, the steps described in the disclosure of the present invention can be executed in parallel, sequentially, or in a different order, as long as the desired results of the technical solution disclosed in the present invention can be achieved, and no limitation is made herein.

[0073] The above specific embodiments do not constitute a limitation on the protection scope of the present invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A perovskite polycrystalline thin film spatial selective passivation device, which is used for passivating uncoordinated lead atoms of deep-level defects and halogen vacancies of shallow-level defects in perovskite, and comprises a laser, a beam adjusting unit and a three-dimensional moving platform; the laser and the beam adjusting unit are coaxially arranged; the three-dimensional moving platform drives the perovskite polycrystalline thin film sample to perform three-dimensional movement; and it is characterized in that: The beam adjustment unit includes a first aperture diaphragm, an attenuator, a second aperture diaphragm, a chopper, and a cylindrical lens that are coaxially arranged in sequence; The first aperture diaphragm and the second aperture diaphragm are arranged in the emission direction of the laser, and are used to modulate the laser beam emitted by the laser, collimate the laser beam and limit the beam diameter; the attenuator is used to control the laser power; the chopper is used to modulate the laser waveform to form a periodically distributed light field; the cylindrical lens is used to focus the laser beam and magnify the scanning range from a point to a plane; The laser emits a laser beam, which enters the first aperture diaphragm for collimation and then the laser power is controlled by the attenuator. After passing through the second aperture diaphragm for secondary collimation, the waveform is modulated by the chopper to generate a beat frequency effect, and then it is focused on the perovskite polycrystalline thin film sample on the three-dimensional moving platform through the cylindrical lens, so as to realize the passivation of the surface of the perovskite polycrystalline thin film sample; When the passivation device performs passivation, set the laser power emitted by the laser and the initial chopper frequency, increase the chopper frequency to the repetition frequency of the laser, and determine the chopper frequency that can preserve the surface of the perovskite thin film; use the beat frequency effect generated by laser pulses to complete the spatial selective passivation of the perovskite polycrystalline thin film at an appropriate chopper frequency. The laser emits a femtosecond laser beam with a repetition frequency of 1000 Hz, and the chopper frequency is 910 Hz - 990 Hz.

2. The perovskite polycrystalline thin film spatial selective passivation device according to claim 1, wherein: The laser beam emitted by the laser has a wavelength band in the infrared or visible light band.

3. The perovskite polycrystalline thin film spatial selective passivation device according to claim 1, wherein: The beam adjustment unit is a rotatable unit.

4. A method for spatially selective passivation of perovskite polycrystalline thin films, which is passivated by using a device for spatially selective passivation of perovskite polycrystalline thin films described in any one of claims 1-3, characterized in that: It includes the following steps: S1. Set the laser power emitted by the laser, and adjust the z-axis of the three-dimensional moving platform at the laser power to determine the focal plane and the defocus distance; after adjusting the defocus distance, place the perovskite polycrystalline thin film sample at a defocus position 500 - 1000 μm behind the focal plane; S2. Set the burn threshold of the laser beam focused on the surface of the perovskite polycrystalline thin film sample to 20 - 50 mW; after determining the defocus distance, reduce the laser power to the burn threshold; S3. Set the initial chopper frequency; adjust the moving speed of the three-dimensional moving platform under the conditions of the defocus distance, the burn threshold, and the initial chopper frequency; S4. Increase the chopper frequency to the repetition frequency of the laser, and determine the chopper frequency that can preserve the surface of the perovskite thin film; use the beat frequency effect generated by laser pulses to complete the spatial selective passivation of the perovskite polycrystalline thin film at an appropriate chopper frequency.

5. A method for spatially selective passivation of perovskite polycrystalline thin films according to claim 4, characterized in that: The moving speed of the three-dimensional moving platform is 0.001 - 3 mm / s.

6. A method for spatially selective passivation of perovskite polycrystalline thin films according to claim 5, characterized in that: The power value of the femtosecond laser beam is 4 mW; the defocus distance is 500 μm; the moving speed of the three-dimensional moving platform is 0.5 mm / s; the chopper frequency is 950 Hz.

7. A perovskite polycrystalline thin film prepared by the method for spatially selective passivation of a perovskite polycrystalline thin film according to any one of claims 4 to 6, characterized in that: The perovskite crystal thin film is a three-dimensional perovskite polycrystalline thin film of the ABX3 type, a two-dimensional perovskite polycrystalline thin film of the A2BX4 type, or a composite perovskite polycrystalline thin film; In the ABX3-type three-dimensional perovskite polycrystalline thin film, A is any one of cesium, methylamine, or formamidine, or a doping of two or more of them in any proportion; in the ABX3-type three-dimensional perovskite polycrystalline thin film, B is lead, tin, or a doping of lead and tin in any proportion; in the ABX3-type three-dimensional perovskite polycrystalline thin film, X is any one of bromine, iodine, chlorine, or fluorine, or a doping of two or more of them in any proportion; In the A2BX4-type two-dimensional perovskite polycrystalline thin film, A is any one of phenethylamine, phenylpropylamine, phenylbutylamine, or butylamine, or a doping of two or more of them in any proportion; in the A2BX4-type two-dimensional perovskite polycrystalline thin film, B is lead, tin, or a doping of lead and tin in any proportion; in the A2BX4-type two-dimensional perovskite polycrystalline thin film, X is any one of bromine, iodine, chlorine, or fluorine, or a doping of two or more of them in any proportion.

8. An LED device, characterized in that: It sequentially includes a cathode, an electron transport layer, a photosensitive layer, a hole transport layer, and an anode from bottom to top; the material of the photosensitive layer is the perovskite polycrystalline thin film described in claim 7.

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