A device and method for lateral regional melting recrystallization of perovskite film

Abstract

The present invention discloses a device and method for crystallization and recrystallization of amorphous or polycrystalline thin film materials of organic-inorganic metal halide perovskite and its derivatives, particularly involving lateral regional melting recrystallization, and applied to amorphous or polycrystalline thin films of perovskite, which is conducive to reducing the gaps between crystal domains, eliminating the interface between crystal domains and increasing the crystal domains. The device includes a radiation source, a focusing and scanning unit, an atmosphere control environment of the film, a heating platform of the film and a heater of the precursor, etc. The present invention is suitable for photovoltaic films, LED display light-emitting films, image detector films and x-ray image detector films that require large-area perovskite single crystals, quasi-single crystals or polycrystalline with large crystal domains.

Description

Technical Field

[0001] The present invention relates to the preparation of crystalline thin film materials of organic-inorganic metal halide perovskites and their derivatives, and to the crystallization and recrystallization of thin films, and in particular to a method of lateral zone melting recrystallization. The present invention also relates to a method for achieving dynamic balance of vapor pressure of each component in a multi-component crystalline thin film material. The present invention also relates to a device for achieving lateral zone melting recrystallization, and in particular to a method for achieving precise control of temperature, temperature gradient and translational velocity of lateral zone melting under the condition of maintaining dynamic balance of vapor pressure of each component. The method, device principle and device of the present invention are suitable for photovoltaic thin films, LED display light-emitting thin films, image detector thin films and x-ray image detector thin films, which require large-area perovskite single crystals, quasi-single crystals or polycrystals with large crystal domains. Background Art

[0002] Thin-film solar cells based on organic-inorganic metal halide perovskites prepared by solution crystal growth have made rapid progress in the past decade, but before they can replace crystalline silicon solar cells, there are still some serious problems to be solved, such as stability and retracement. One of the root causes of the problem is that the crystal domains of metal halide perovskite polycrystalline thin films obtained by the current preparation method are relatively small, and their size is related to various parameters and processes of the process, and is generally below micrometers; there are still a large number of gaps between the crystal domains, and there are subgrain boundaries in the crystal domains. There are also many vacancies, dangling bonds, dislocations and other defects and impurities at the interface of the crystal domains; the organic cations that originally belonged to the perovskite lattice on the interface and subinterface are also easy to move out and translocate during the aging process; the size of the crystal domain also limits the diffusion length of the carrier to the order of micrometers, which is a big gap from the hundreds of micrometers required by the device.

[0003] In the existing solution growth method technology, the one-step spin coating method or the two-step spin coating-immersion method usually adopted requires the use of solvents to dilute the precursor and use additives. In the preparation process, there is a heating or light irradiation annealing (alloy) process to promote nucleation and crystallization, and also to promote the volatilization of solvents and additives. The annealing temperature is lower than the melting point of the precursor and the crystal domain. For example, in the preparation of methylamine lead iodide, in order to prevent the escape of the methylamine lead iodide precursor, the annealing temperature is generally selected below 150°C, which is lower than the melting point of methylamine lead iodide and methylamine lead iodide.

[0004] In the document "Impact of Processing Temperature and Composition on the Formation of Methylammonium Lead Iodide Perovskites" (Chem. Mater. 2015, 27, 4612-4619), Song Zhao Ning et al. pointed out that high temperature annealing without atmosphere control will lead to the gasification and escape of methylammonium iodide, deteriorating the surface morphology. The authors used a sealed graphite box to reach the equilibrium vapor pressure of methylammonium iodide, and the annealing temperature was raised to 190°C, which can keep the composition of the polycrystalline unchanged, but did not improve the morphology and interface state of the crystal.

[0005] In the document "Enhanced Carrier Lifetimes of Pure Iodide Hybrid Perovskite via Vapor Equilibrated Re-Growth (VERG)" (J. Phys. Chem. Lett. 2015, 6, 2503-2508), BSTosun et al. made an improvement by adding methyl ammonium iodide vapor in a sealed atmosphere environment, so that the methyl ammonium lead iodide film after crystallization could be regrown and the crystal domain size of the polycrystalline was slightly increased.

[0006] In the document "Atmospheric Processing of Perovskite Solar Cells Using Intense Pulsed Light Sintering" (Journal of Electronic Materials, Vol. 47, No. 2, 2018, 1285-1292), K. Ankireddy et al. used short-pulse xenon lamp radiation annealing in an uncontrolled atmospheric environment. The pulse action time was 2ms, the incident energy density of each pulse was 26mJ / cm2, and the number of pulses ranged from several to 20. Although the surface morphology was partially improved, the crystal domains of the polycrystalline did not increase.

[0007] In the document "High-efficiency solution-processed perovskite solar cells with millimeter-scale grains" (Science, Vol. 347, Issue 6221, 2015, 522-525), W. Nie et al. proposed a hot casting method. Different from the usual preparation method of room temperature spin coating followed by heating (30-150°C) annealing, the method adopts a method of high temperature (180°C) spin coating followed by low temperature (100°C) annealing, which significantly increases the crystal domain.

[0008] The US patent "Methods of Thermally Induced Recrystallization" with publication number US10128052B1 authorized in 2018 also adopts a recrystallization method to address the problem of small crystal domains in thin films grown by solution crystallization growth method: methylamine (CH3NH2) gas reacts with methylamine lead iodide polycrystalline thin films grown by conventional methods to form a gas-liquid phase at room temperature. During the subsequent heating, methylamine vaporizes, and the methylamine lead iodide film undergoes a recrystallization process, and the average size of the formed polycrystalline domains reaches 15 microns. However, it does not explain why recrystallization starts from a certain edge and then gradually expands horizontally to the entire sample during the heating process.

[0009] Historically, similar domain problems have existed for amorphous silicon and polycrystalline silicon thin film materials. Since the 1980s, a lateral zone melting recrystallization technology (ZMR) has been developed for the preparation of crystalline silicon thin films (SOI) on silicon dioxide layers. It performs lateral zone melting on amorphous silicon / polycrystalline silicon thin films on a silicon dioxide thin layer on a silicon substrate, and recrystallizes single-crystal silicon thin films, quasi-single-crystal silicon thin films, or polycrystalline silicon thin films, depending on whether there is a seed crystal. The 1983 U.S. Patent No. 4371421 "Lateral epitaxial growth by seeded solidification", the 1995 U.S. Patent No. 5453153 "Zone-melting recrystallization process", and the 2011 Chinese Patent No. CN200980108990.8 "Zone-melting recrystallization process for inorganic film materials" describe the lateral zone melting recrystallization technology and devices used by each, but they are limited to silicon-based semiconductor films. There are no reports on its use in compound semiconductor films or perovskite films. In compound semiconductors or in the preparation of perovskite films, the vapor pressures of the component elements or precursors at the same temperature vary greatly, and the elements or precursors with high vapor pressure values ​​tend to become escape phases and be lost in the lattice. Even in the preparation of single-element semiconductor films such as silicon, the lateral zone melting recrystallization technology also requires a protective layer of silicon oxide or silicon nitride to prevent the escape of molten silicon vapor.

[0010] The lateral zone melting recrystallization technology uses a liquid-solid interface advancement method similar to liquid phase epitaxy for growing single crystal thin films, except that liquid phase epitaxy has macroscopic seeds to induce initial nucleation, or uses a lattice constant matching substrate to induce nucleation, or inlays single crystal seeds at the initial growth of the substrate edge. Obviously, these two measures are not realistic for low-cost perovskite thin films, and are not compatible with the process requirements of large-scale production. Summary of the invention

[0011] The crystal domains of the methylamine lead iodide polycrystalline film obtained by the conventional solution crystallization growth method are too small, and there are too many problems between the crystal domains. The fundamental solution is to convert the polycrystalline film into a single crystal film, so as to fill the gaps between the crystal domains, eliminate the sub-interfaces inside the crystal domains, and remove the interfaces between the crystal domains. Due to the characteristics of the precursors of the solution method, the growth temperature cannot be too high, resulting in the inability to directly grow into a single crystal or quasi-single crystal film. The present invention develops a lateral zone melting recrystallization technology and applies it to amorphous or polycrystalline films of perovskites, so that the high temperature only exists near the liquid-solid interface promoted by the lateral growth, thereby avoiding the influence of high temperature on the entire film for too long, and at the same time has the advantage of controllable liquid-solid interface temperature gradient promotion of crystal epitaxial growth.

[0012] On one hand, the present invention provides a device for lateral regional melting and recrystallization of a perovskite film, which includes a radiation source, a focusing and scanning unit, an atmosphere control environment for the film, a heating platform for the film, and a heater for a precursor.

[0013] According to the above scheme, the radiation source is a resistance heating source including nickel-chromium wire, iron-chromium-aluminum wire or carbon rod that generates radiation in the far infrared to infrared band, or a light source including light emitting diode (LED), laser diode (LD), laser or high-pressure gas discharge lamp that generates radiation in the near infrared to ultraviolet band. The main wavelength range of the light source radiation should fall within the optical absorption band of the film.

[0014] According to the above scheme, the focusing unit is a lens, a light-guiding element, a diffraction element or a reflection element matched with the radiation source, which can focus into a point-shaped, rectangular or linear local area in the film, such as a light pipe or a light-guiding plate matched with a light-radiating diode, a double cylindrical lens matched with a laser diode or an elliptical curved reflector matched with a linear xenon lamp, etc.; the scanning unit enables the focused local area to produce a relative speed-controllable traversal movement with respect to the film plane, such as a two-dimensional galvanometer, a one-dimensional or two-dimensional motion platform.

[0015] According to the above scheme, the atmosphere control environment of the film can be set to vacuum, inert gas introduction or precursor gas introduction, such as a sealed stainless steel container of suitable volume with optical windows, equipped with gas inlet valves and exhaust valves, equipped with an external gas control panel, vacuum pump and gas source.

[0016] According to the above scheme, the heating platform of the thin film uniformly heats or cools the thin film sample and the temperature can be controlled, for example, from room temperature to 350° C. A balance should be made between a faster heating and cooling rate and better temperature uniformity, and a water cooling pipeline should be configured.

[0017] According to the above scheme, the precursor heater is used to place the precursor powder and achieve a certain vapor pressure of the precursor by heating or cooling, such as from room temperature to 350° C. A balance must be made between a faster heating and cooling rate and better temperature uniformity, and a water cooling pipeline is configured.

[0018] Another aspect of the present invention provides a method for lateral zone melting recrystallization of a perovskite film, which uses a liquid-solid interface advancement method similar to liquid phase epitaxy to control the liquid-solid boundary advancement speed of the zone melting, thereby controlling the lateral recrystallization growth temperature gradient. The method includes the following steps:

[0019] (1) In an inert gas protected environment, a substrate containing a perovskite film to be melted and recrystallized in a lateral region is placed on a sample heating platform.

[0020] (2) The atmosphere control environment is sequentially set to be closed, evacuated, for example, the vacuum degree is 10 KPa, and an inert gas, such as nitrogen, is introduced.

[0021] (3) Heating a precursor heater containing precursor powder and controlling the heating temperature so that the precursor vapor pressure is maintained at a pressure value close to the saturated vapor pressure. For example, the temperature of the precursor heater of methyl iodide ammonium powder is within the range of 50-180°C.

[0022] (4) Adjust the temperature of the heating platform to a temperature lower than the melting point of the film and maintain the temperature therein, for example, within the range of 50-150°C for methylamine lead iodide film.

[0023] (5) Start the radiation source, focusing and scanning units, set the appropriate radiation intensity, focus area size, scanning speed and scanning mode, so that the temperature of the focus area in the film rises above the melting point of the film, and scans through the film sample. For example, for the perovskite film of methylamine lead iodide, the above parameters need to be coordinated so that the incident energy density ranges from 100mJ / cm2 to 50J / cm2.

[0024] The advantages of the present invention are:

[0025] 1. The device, technology and method for lateral regional melting and recrystallization of perovskite films of the present invention are suitable for low-cost large-scale production and are applicable to photovoltaic films, LED display light-emitting films, image detector films and X-ray image detector films, etc., which require larger-area perovskite quasi-single crystals or larger-domain polycrystals.

[0026] 2. The perovskite quasi-single crystal film or polycrystalline film with larger crystal domains prepared by the present invention reduces the gaps between crystal domains, reduces the sub-interfaces within the crystal domains, reduces the interfaces between crystal domains, and improves the stability and retracement problems of the current perovskite polycrystalline film. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic diagram of the first embodiment of the present invention. A laser is used as a radiation source, a two-dimensional galvanometer is used as a scanning unit, and a special-shaped lens is used as a focusing unit.

[0028] Figure 2 This is a schematic diagram of the second embodiment of the present invention. A laser is used as a radiation source, a two-dimensional moving platform in the xy direction is used as a scanning unit, and a special-shaped lens is used as a focusing unit.

[0029] Figure 3 This is a schematic diagram of the third embodiment of the present invention. A light radiating diode is used as a radiation source, a one-dimensional moving platform in the x direction is used as a scanning unit, and a special-shaped light guide plate is used as a focusing unit. DETAILED DESCRIPTION

[0030] The following non-limiting embodiments may enable a person skilled in the art to more fully understand the present invention, but are not intended to limit the present invention in any way.

[0031] The test methods described in the following examples are conventional methods unless otherwise specified; the reagents and materials described are commercially available unless otherwise specified.

[0032] The method for preparing the sample of the perovskite precursor thin film or polycrystalline thin film used to achieve lateral zone melting recrystallization in the following embodiments adopts a typical one-step spin coating method, with reference to the literature Science 2012, 338, 643-647 and Sci. Rep. 2012, 2, 591. The steps are:

[0033] Step 1, synthesize and prepare the precursor methyl ammonium iodide (CH3NH3PbI), a 33wt% methylamine solution (CH3NH2) containing ethanol solution and a 57wt% iodine chloride (HI) containing water are reacted in a nitrogen atmosphere for 2 hours, the solvent is evaporated at 80°C, and then washed with diethyl ether three times, and finally vacuum dried to obtain a white powder.

[0034] Step 2, the synthesized methylamine iodide and lead diiodide (PbI2) are dissolved in a polar aprotic solvent of anhydrous dimethylformamide (DMF) at a certain molar ratio (such as a ratio of 1:1 equivalent to the components of methylamine lead triiodide).

[0035] Step 3, the soda-lime-silica glass used as the substrate is decontaminated and degreased, ultrasonically cleaned alternately in hot or cold deionized water for 15 minutes each, spin-coated with an ethanol solution containing diisopropoxide titanium di(acetylacetonate), annealed at 500°C in an air atmosphere for 30 minutes to obtain an ITO film.

[0036] Step 4: Spin-coat the precursor solution prepared in step 2 onto the above-mentioned ITO glass substrate in a nitrogen environment at a rotation speed of 2000 rpm to obtain a precursor film.

[0037] Step 5, placing the ITO glass carrying the precursor film on a hot plate and annealing it in a nitrogen atmosphere at a temperature between 30°C and 150°C for 30 minutes, to obtain a perovskite polycrystalline film of methylamine lead triiodide with different crystal domain morphology, depending on the degree of annealing.

[0038] The above steps 1 to 5 are a one-step method for preparing a polycrystalline perovskite film of methylamine lead triiodide. Polycrystalline or amorphous perovskite films prepared by other different methods such as a two-step method or a hot casting method are also applicable to the following embodiments.

[0039] The composition of the atmosphere control environment of the film used in the embodiment is as follows Figure 1 1. Figure 2 1 and Figure 31 in the figure. The specific description is as follows: a shallow cylindrical or square container 11 is made of stainless steel plate, a wide edge is welded on the upper end of the container, a groove is milled on it to place the sealing fluororubber ring 11, and a container cover 12 containing a borosilicate glass or quartz glass window is placed on the sealing fluororubber ring 11 on the wide edge, and the edge is locked with a clamp (not shown) to achieve gas sealing in the container. The vacuum degree in the container reaches 10KPa and the pressure reaches 0.3MPa. The material type of borosilicate glass or quartz glass 12 needs to be determined according to the wavelength of the radiation source, and the material with the smallest absorption of radiation and less than 10% absorption rate is selected. The sample electric heating platform 13 heats the ITO glass substrate 14 carrying the perovskite polycrystalline film, which is placed in the sealed container 11, and the foot pad 15 is made of heat-resistant and heat-insulating ceramics. The interior of the electric heating platform 13 is heated by electric heating wires, and the exterior is a cast copper or cast aluminum block with a water cooling pipeline, and the surface is polished. The temperature of the electric heating platform 13 is controlled by a microprocessor and can reach 350°C with a control accuracy of 1°C, a heating rate of 20°C / minute, and a cooling rate of 10°C / minute. The precursor electric heater 16 heats the precursor powder methyl iodide placed therein, which is placed in a sealed container 11 and is made of heat-resistant and heat-insulating ceramics and other materials as foot pads 17. The electric heater 16 is heated by electric heating wires inside, and the outside is a cast copper or cast aluminum block with a water cooling pipeline, and the surface is polished. The temperature of the electric heater 16 is controlled by a separate microprocessor and can reach 350°C with a control accuracy of 1°C, a heating rate of 20°C / minute, and a cooling rate of 10°C / minute. The sealed electrical connector 18 installed on the side of the container 11 provides a power connection line and a thermocouple connection line 21 to connect to the power input terminal and the thermocouple output terminal on the sample electric heating platform 13. The sealed electrical connector 19 installed on the side of the container 11 provides power connection wires and thermocouple connection wires 22 connected to the power input terminal and thermocouple output terminal of the precursor electric heater 16. Two gas valves 20 installed on the side of the container 11 are used to connect the pipeline to the external gas path to realize the intake of nitrogen and the extraction of gas in the cavity.

[0040] The radiation source can generally be a resistive heating source that generates radiation in the far infrared to infrared band, including nickel-chromium wire, iron-chromium-aluminum wire or carbon rod, or a light source that generates radiation in the near infrared to ultraviolet band, including a light emitting diode (LED), a laser diode (LD), a laser or a high-pressure gas discharge lamp. In the selection of the following embodiments, it is necessary to comprehensively consider factors such as the heating mechanism and wavelength range of the radiation, the size of the radiation focus area and the incident energy density, and the interference effect of the radiation source on the sample. The specific analysis is as follows:

[0041] Factor 1, heating mechanism and wavelength range. It is known that the absorption band wavelength of methylamine lead triiodide extends from about 800nm ​​(1.55eV) to the short wavelength direction, and the absorption band wavelength of the precursor lead diiodide extends from about 550nm (2.4eV) to the short wavelength direction, while the other precursor methylamine iodide is a wide bandgap, with an absorption wavelength higher than ultraviolet, and is transparent to the above-mentioned commonly used radiation sources. Since the heating mechanism caused by radiation on the thin film sample mainly comes from the relaxation after inter-band absorption, the radiation in the far-infrared to infrared band is rarely absorbed in the thin film sample, so the resistance heating source is not preferred. Semiconductor lasers with blue-violet light of 405nm, blue light of 450nm, green light of 520nm or 532nm, frequency-doubled YAG lasers, and high-power LEDs with similar wavelength ranges are all options.

[0042] Factor 2, the size of the radiation focus area and the incident energy density. The process of lateral zone melting and recrystallization is most closely related to the temperature gradient of the lateral liquid-solid interface. This in turn depends on the radiation intensity, scanning speed, the width of the focus area in the scanning direction, and the heating temperature of the sample electric heating platform 13. Taking a semiconductor device with an output radiation power of 5W as an example, if the focus area is a rectangular area with a long side of 5mm and a short side of 0.4mm, the power density is 250W / cm2; if the scanning speed along the short side is 10mm / s, the laser action time in the focus area is 40ms, and the combined incident energy density is 10J / cm2. At this time, the energy absorbed in the scanned focus area is 0.2J. In actual operation, the above parameters need to be coordinated so that the incident energy density ranges from 100mJ / cm2 to 50J / cm2. The aspect ratio of the focus area is preferably larger. When other conditions such as power density remain unchanged, the incident energy density is reduced, which can reduce the vaporization loss of the precursor.

[0043] Factor 3, the interference effect of the radiation source on the sample. Generally speaking, the radiation source and the sample need to be kept as far away as possible, and it is best to have atmosphere isolation between them. This optimal distance depends on the size of the radiation source, the radiation angle and the corresponding focusing unit. The resistance heating source can be heated in the form of a resistance wire. Because the radiation is 360 degrees in all directions, it needs to be combined with an elliptical cylindrical reflector to focus the light. In order to make it not too large, the distance between the two foci of the ellipse will be shorter, making it difficult to achieve atmosphere isolation. The high-pressure gas discharge lamp is a point light source, and the radiation is at a full three-dimensional angle. It needs to be combined with an ellipsoidal reflector to focus the light. For the same reason, it is difficult to achieve atmosphere isolation. Light radiating diodes (LEDs), laser diodes (LDs) or other lasers are equipped with suitable lenses or aspherical special-shaped lenses, which are easier to achieve atmosphere isolation and radiation line scanning.

[0044] Embodiment 1:

[0045] The schematic diagram of this example is as follows Figure 1 As shown, the light source and scanning focusing assembly 3 adopts a laser galvanometer scanner 3 composed of a semiconductor laser module 31 and a galvanometer pair 32 and 33. The laser selects a 450nm semiconductor laser of blue light with an output power of 3W. A special-shaped focusing lens is used in the module, and its optical path to the focused light spot is 0.5m. The imaged focused light spot is a rectangular area with a long side of 5mm and a short side of 0.4mm. The rotation angle of the laser module 31 is adjusted so that the rotation of the galvanometer 32 produces movement of the light spot along the short side, and the rotation speed is set so that the scanning speed of the light spot on the sample is 10mm / sec. Then, the galvanometer 31 is made to have a small rotation increment so that the light spot moves in the long side direction. The offset on the sample is slightly smaller than the length of the long side of the light spot, which is slightly less than 5mm in this case. Repeat this process until the entire perovskite film sample is traversed.

[0046] Embodiment 2:

[0047] The schematic diagram of this example is as follows Figure 2 As shown, the light source and scanning focusing assembly 4 adopts a semiconductor laser module 41 and an xy two-dimensional plane linear motion platform composed of a y-axis sliding arm 42, an x-axis lead screw and a slide rail 43, a y-axis lead screw 44, and a y-axis slide rail 45. The laser selects a 450nm semiconductor laser of blue light with an output power of 3W. A special-shaped focusing lens is used in the module, and its optical path to the focused light spot in the z direction is 100mm, which is fixed after fine-tuning. The focused light spot is a rectangular area with a long side of 5mm and a short side of 0.4mm. The rotation angle of the laser module 41 is adjusted so that the short side of the focused light spot is parallel to the x-direction of the motion platform 4, and the movement speed of the laser module 41 in the x-direction is 10mm / sec. Then the sliding arm 42 moves an offset in the y direction, which is slightly less than the length of the long side of the light spot, in this case slightly less than 5mm. This is repeated until the entire perovskite film sample is traversed.

[0048] Embodiment three:

[0049] The schematic diagram of this example is as follows Figure 3As shown, the light source and scanning focusing assembly 5 uses a light radiating diode module 51 and a one-dimensional linear motion platform composed of an x-axis fixed frame 52, an x-axis lead screw and a slide rail 53. The light radiating diode module 51 uses 10 high-power light radiating diodes 54, whose wavelength is 405nm and the output power is 3W per unit. The light radiating diode 54 is coupled with one end of the parallel surface of the special-shaped light guide plate 55 placed along the z direction, and the parallel surface of the light guide plate 55 transitions to a conical surface, and finally transitions to a cylindrical lens as the output end. The optical path from the output end to the focused light spot is 30mm, which is fixed after fine-tuning. The focused light spot is a rectangular area with a long side of 50mm and a short side of 0.4mm. The rotation angle of the module 51 is adjusted so that the short side of the focused light spot is parallel to the motion direction of the motion platform 5, that is, the x direction. The moving speed of the module 51 in the x direction is 10mm / sec. If the side length of the perovskite film sample is shorter than 50mm, the entire sample can be traversed at one time. If the side length of the sample is greater than 50 mm, the length of the light guide plate can be lengthened and the number of light radiating diodes can be increased accordingly.

Claims

1. A device for lateral regional melting and recrystallization of a perovskite film, characterized in that It includes a radiation source, a focusing unit, a scanning unit, an atmosphere control environment for the film, a heating platform for the film sample, and a heater for the precursor; The heating platform is used to place the perovskite film to be melted and recrystallized in the lateral region; The atmosphere control environment is used to be set to vacuum, inert gas and closed precursor vapor with controllable vapor pressure in a certain time sequence; The temperature of the heating platform is raised to a certain temperature lower than the melting point of the film, the radiation source, the focusing unit and the scanning unit are started, and appropriate radiation intensity, focal area size, scanning speed and scanning mode are selected so that the temperature of the focal area of ​​the radiation beam in the film is raised to above the melting point of the film; After scanning through the film, the radiation source, the focusing unit, and the scanning unit are turned off; The temperature of the heating platform is reduced to room temperature to obtain a prepared film; The radiation source is a resistance heating source that generates radiation in the far infrared to infrared band, or a light source that generates radiation in the near infrared to ultraviolet band.

2. The device for lateral regional melting recrystallization of a perovskite film according to claim 1, characterized in that The resistance heating source includes nickel-chromium wire, iron-chromium-aluminum wire or carbon rod, and the light source includes a light emitting diode (LED), a laser or a high-pressure gas discharge lamp.

3. The device for lateral zone melting recrystallization of a perovskite film according to claim 2, characterized in that: The laser includes a laser diode (LD).

4. The device for lateral regional melting recrystallization of a perovskite film according to claim 1, characterized in that The focusing unit focuses the radiation generated by the radiation source into a point-shaped or rectangular local area in the film through a light-guiding element, a diffraction element or a reflection element; the scanning unit causes the focused local area to produce a relative speed-controllable traversal movement on the film plane.

5. The device for lateral zone melting recrystallization of a perovskite film according to claim 4, characterized in that The light-guiding element includes a lens; and / or the rectangular local area includes a linear local area.

6. The device for lateral zone melting recrystallization of a perovskite film according to claim 1, characterized in that The atmosphere control environment of the film is a closable space, in which a vacuum is set, an inert gas is introduced, or a precursor gas is introduced.

7. The device for lateral regional melting recrystallization of a perovskite film according to claim 1, characterized in that The heating platform for the thin film sample uniformly heats or cools the thin film sample and the temperature is controllable.

8. The device for lateral regional melting recrystallization of a perovskite film according to claim 1, characterized in that The precursor heater is positioned to heat or cool the precursor powder to control the vapor pressure of the precursor.

9. A method for lateral zone melting recrystallization of a perovskite film, which is carried out using the device for lateral zone melting recrystallization of a perovskite film according to any one of claims 1 to 8, characterized in that The perovskite film to be melted and recrystallized in the lateral region is placed on the heating platform; the atmosphere control environment is set to vacuum, inert gas and closed precursor steam with controllable steam pressure in a certain time sequence; the temperature of the heating platform is raised to a certain temperature lower than the melting point of the film; the radiation source, focusing unit and scanning unit are started, and the appropriate radiation intensity, focusing area size, scanning speed and scanning mode are selected so that the temperature of the focusing area of ​​the radiation beam in the film is raised above the melting point of the film; after scanning through the film, the radiation source, focusing unit and scanning unit are turned off, the temperature of the heating platform is reduced to room temperature, and the prepared film is taken out.

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