Vacuum flash evaporation equipment and method for preparing perovskite thin film

Abstract

The invention provides vacuum flash evaporation equipment and a vacuum flash evaporation method for preparing a perovskite thin film. Comprising a cavity, a vacuum device, a heating device and a bearing device, the cavity comprises a flash evaporation cover and a base which are arranged up and down, and the flash evaporation cover is of an inverted U-shaped structure; a hidden exhaust pipeline is arranged in each side wall of the flash evaporation cover, one end of each hidden exhaust pipeline extends to and penetrates through a side wall air outlet of the flash evaporation cover, and the other end of each hidden exhaust pipeline extends to and penetrates through an open end exhaust opening in the side wall of the flash evaporation cover to be communicated with an inner cavity of the cavity; the vacuum device is positioned on the outer side of the cavity, is communicated with an air outlet in the side wall of the flash evaporation cover through a vacuum pipeline and is used for exhausting air; the heating device is used for providing heat for the cavity to promote rapid evaporation of a solvent in the perovskite thin film; the bearing device is connected with the base and used for bearing a substrate coated with a perovskite film. According to the invention, the air flow in the inner cavity is prevented from fluctuating, and the problem of difference of crystallization speeds and quality in different regions of perovskite is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of solar cells and relates to the technical field of preparation of perovskite films, and in particular to a vacuum flash evaporation device and a method for preparing perovskite films. Background Art

[0002] Perovskite Solar Cells (PSCs) are a new type of photovoltaic technology that has attracted much attention for its advantages such as high conversion efficiency, low cost and easy preparation. Among them, VCD (Vacuum Flash Drying) technology is one of the key core equipment urgently needed for the industrialization of perovskite cells. In the early days of perovskite solar cell research, VCD technology began to be explored for the preparation of perovskite films. Researchers have found that through VCD technology, the evaporation rate and deposition thickness of perovskite materials can be precisely controlled, thereby preparing high-quality perovskite films.

[0003] With the in-depth study of perovskite materials and VCD technology, researchers have continuously optimized VCD process parameters, such as evaporation source temperature, evaporation rate, substrate temperature, vacuum degree, etc. By precisely controlling these parameters, the perovskite film can have better crystallinity, more uniform grain size, and lower defect density, thereby significantly improving the performance of the battery and rapidly improving the efficiency of perovskite solar cells, from the initial low efficiency to a certain competitive level; at the same time, in the process of preparing perovskite solar cells with VCD technology, researchers found that by optimizing the growth conditions and post-processing process of the film, the stability of the perovskite film can be improved. For example, the use of appropriate annealing processes, the addition of specific additives and other methods can improve the crystallization quality and interface characteristics of the perovskite film, thereby enhancing the stability of the battery under different environmental conditions and extending its service life.

[0004] However, although VCD technology can achieve good film uniformity in theory, in actual operation, it is difficult to obtain a completely uniform film on a large-area substrate due to the special properties of perovskite materials and slight changes in equipment parameters. The uneven film thickness will lead to a decrease in the photoelectric conversion efficiency of the battery, and in the series battery, it will also cause current matching problems, reducing the performance of the entire battery module; in addition, the parameters such as the evacuation speed and evacuation uniformity of VCD greatly affect the crystallization quality of the perovskite film. Parameters such as temperature, pressure, and evaporation rate in the VCD process will affect the crystallization process of the perovskite. Improper control will lead to incomplete crystallization, uneven grain size or defects, thereby increasing the recombination probability of carriers and reducing the efficiency and stability of the battery.

[0005] At present, there are three common VCD exhaust positions: top exhaust, bottom exhaust and side exhaust. The top exhaust can timely and effectively discharge the volatile substances and by-products produced in the reaction process, and prevent them from falling back to the film surface after gathering at the top of the reaction chamber, thereby reducing the impact on the quality of the perovskite film. However, the top exhaust may make the air flow speed in the reaction chamber faster, which may cause certain disturbances to the film growth on the substrate and affect the longitudinal growth of the perovskite film; the bottom exhaust can make the pressure distribution in the reaction chamber more uniform, thereby ensuring the deposition rate and uniformity of the precursor material on the substrate. Compared with the top exhaust, the bottom exhaust has less disturbance to the air flow in the reaction chamber, which is conducive to the stable growth of the perovskite film. However, the exhaust effect of the volatile substances and by-products produced in the reaction process may not be as good as the top exhaust, which may easily cause these substances to gather at the top of the reaction chamber, thereby affecting the quality of the perovskite film.

[0006] Compared with the first two pumping methods, side pumping can balance the pressure distribution in the reaction chamber to a certain extent and avoid uneven pressure. At the same time, the position of side pumping is relatively flexible and can be adjusted according to specific reaction requirements and equipment structure to ensure uniform deposition of precursor substances on the substrate. However, side pumping may also change the direction of the airflow in the reaction chamber, thereby affecting the deposition direction and uniformity of perovskite on the substrate.

[0007] Therefore, how to avoid the change of air flow direction in the reaction chamber during side vacuuming and reduce the impact on the crystallization speed and uniformity of perovskite on the substrate is a technical problem that needs to be solved urgently. Summary of the invention

[0008] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a vacuum flash evaporation device and method for preparing a perovskite film. The present invention designs a hidden exhaust pipeline to evenly distribute the exhaust area to all directions of the substrate coated with the perovskite film, thereby avoiding fluctuations in the air flow in the inner cavity, reducing the impact on the crystallization speed and uniformity of the perovskite on the substrate, and effectively improving the difference in crystallization speed and quality of different regions of the perovskite caused by the offset exhaust port position, balancing the pressure distribution in the inner cavity, and avoiding the occurrence of uneven pressure.

[0009] To achieve this object, the present invention adopts the following technical solutions:

[0010] In a first aspect, the present invention provides a vacuum flash evaporation device for preparing a perovskite film, comprising a cavity, a vacuum device, a heating device and a carrying device;

[0011] Wherein, the cavity includes a flash cover and a base arranged up and down, and the flash cover is an inverted U-shaped structure; each side wall of the flash cover is provided with a hidden exhaust pipeline, one end of the hidden exhaust pipeline extends to and passes through the side wall air outlet of the flash cover, and the other end of the hidden exhaust pipeline extends and passes through the open end exhaust port of the side wall of the flash cover, and is connected with the inner cavity of the cavity.

[0012] The vacuum device is located outside the cavity, and is connected to the side wall air outlet of the flash cover through a vacuum pipeline for exhausting air; the heating device is used to provide heat to the cavity to promote rapid evaporation of the solvent in the perovskite film; the supporting device is connected to the base and is used to support the substrate coated with the perovskite film.

[0013] The present invention designs a hidden exhaust pipeline to evenly distribute the exhaust area to all directions of the substrate coated with the perovskite film, thereby avoiding fluctuations in the air flow in the inner cavity, reducing the impact on the crystallization rate and uniformity of the perovskite on the substrate, and effectively improving the difference in crystallization rate and quality of different areas of the perovskite caused by the offset exhaust port position, balancing the pressure distribution in the inner cavity, and avoiding the occurrence of uneven pressure.

[0014] Preferably, the cavity has a feed port and a discharge port for inputting and outputting substrates coated with perovskite thin films.

[0015] Preferably, the base is a positive U-shaped structure, corresponding to the flash cover of the inverted U-shaped structure.

[0016] Preferably, the thickness of the hidden exhaust pipeline is 30-100 mm, for example, 30 mm, 40 mm, 50 mm, 60 mm or 100 mm, etc.; wherein the thickness direction of the hidden exhaust pipeline is the same as the thickness direction of the side wall of the flash cover.

[0017] Preferably, along the direction from the air extraction port to the air outlet, the width of the hidden air extraction pipeline shows a decreasing trend; wherein, the width direction of the hidden air extraction pipeline is perpendicular to the thickness direction of the hidden air extraction pipeline.

[0018] Preferably, each side wall of the flash cover has at least one side wall air outlet, for example, 2, 3, 4 or 5 side wall air outlets.

[0019] Preferably, the side wall air outlet is circular, with a diameter of 30-100 mm, for example, 30 mm, 40 mm, 50 mm, 60 mm, 80 mm or 100 mm.

[0020] Preferably, the air outlet of the side wall of the flash cover and the air suction port at the open end of the side wall of the flash cover are not on the same horizontal plane.

[0021] Preferably, the air extraction port at the open end of the side wall of the flash cover is located on a side of the open end of the side wall of the flash cover close to the inner cavity and is parallel to the horizontal reference plane.

[0022] It should be noted that the horizontal reference plane refers to an ideal plane parallel to the base placement plane.

[0023] Preferably, the width of the air suction port at the open end is smaller than the thickness of the side wall of the flash cover on the same side, and the length of the air suction port at the open end is equal to the length of the side wall of the flash cover on the same side.

[0024] Preferably, the vacuum device comprises a vacuum pump, a vacuum pipeline and a vacuum valve.

[0025] Preferably, the vacuum pump is connected to the air outlet of the side wall of the flash cover through the vacuum pipeline, and the vacuum valve is arranged on the vacuum pipeline to adjust the exhaust speed of the hidden exhaust pipeline.

[0026] In a second aspect, the present invention provides a method for preparing a perovskite film, the method using the vacuum flash evaporation device as described in the first aspect, comprising the following steps:

[0027] The substrate coated with the perovskite precursor film is placed on a carrier device.

[0028] The parameters of the vacuum flash evaporation equipment are set, and then the vacuum device and the heating device are started to perform vacuum flash evaporation. After the completion, the obtained perovskite film is taken out.

[0029] Preferably, the setting parameters of the vacuum flash evaporation equipment include:

[0030] The vacuum degree of the inner cavity is 1×10 -2 -1×10 2 Pa, for example, can be 0.01Pa, 0.1Pa, 1Pa or 10Pa, and the drying time is 20-150s, for example, can be 20s, 50s, 80s, 100s or 150s, etc.

[0031] Preferably, in the vacuum flash evaporation equipment, the exhaust speed of the hidden exhaust pipeline is 500-2000sccm, for example, it can be 500sccm, 1000sccm, 1500sccm or 2000sccm.

[0032] Preferably, the chemical formula of the perovskite precursor film is ABX3, wherein A is any one of formamidinium ion, methylamine ion or cesium ion or a combination of at least two thereof, B is lead ion and / or tin ion, and X is a halogen ion.

[0033] Preferably, the thickness of the perovskite film is 300-650 nm, for example, 300 nm, 350 nm, 400 nm, 500 nm, 600 nm or 650 nm, etc.

[0034] Preferably, the grain boundary density of the perovskite film is 1×10 8 -1×10 10 cm -2 , for example, it can be 1×10 8 cm -2 , 5×10 8 cm -2 , 1×10 9 cm -2 , 5*10 9 cm -2 or 1×10 10 cm -2 wait.

[0035] However, it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0036] The numerical range described in the present invention not only includes the point values ​​listed above, but also includes any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] The present invention designs a hidden exhaust pipeline to evenly distribute the exhaust area to all directions of the substrate coated with the perovskite film, thereby avoiding fluctuations in the air flow in the inner cavity, reducing the impact on the crystallization rate and uniformity of the perovskite on the substrate, and effectively improving the difference in crystallization rate and quality of different areas of the perovskite caused by the offset exhaust port position, balancing the pressure distribution in the inner cavity, and avoiding the occurrence of uneven pressure. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a front view of the cavity of the vacuum flash evaporation equipment provided by the present invention.

[0040] Figure 2 A side view of the cavity of the vacuum flash evaporation equipment provided by the present invention.

[0041] Figure 3 This is a bottom view of the cavity of the vacuum flash evaporation equipment provided by the present invention.

[0042] Figure 4 A cross-sectional view of the hidden air extraction pipeline provided by the present invention.

[0043] Among them, 1-flash cover; 2-base; 3-hidden exhaust pipeline; 4-side wall air outlet; 5-exhaust port; 6-inner cavity. DETAILED DESCRIPTION

[0044] It should be understood that, in the description of the present invention, the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0045] It should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "disposed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0046] The technical solution of the present invention is further illustrated below through specific implementation methods.

[0047] In a specific embodiment, the present invention provides a vacuum flash evaporation device for preparing a perovskite film, comprising a cavity, a vacuum device, a heating device and a supporting device.

[0048] The front view, side view and bottom view of the cavity are as follows: Figure 1 , Figure 2 and Figure 3 As shown, it includes a flash cover 1 and a base 2 arranged up and down, and the flash cover 1 is an inverted U-shaped structure; each side wall of the flash cover 1 is provided with a hidden exhaust pipeline 3, one end of the hidden exhaust pipeline 3 extends to and passes through the side wall air outlet 4 of the flash cover 1, and the other end of the hidden exhaust pipeline 3 extends and passes through the open end exhaust port 5 of the side wall of the flash cover 1, and is connected with the inner cavity 6 of the cavity.

[0049] The vacuum device is located outside the cavity, and is connected to the side wall air outlet 4 of the flash cover 1 through a vacuum pipeline for exhausting air; the heating device is used to provide heat to the cavity to promote rapid evaporation of the solvent in the perovskite film; the supporting device is connected to the base 2, and is used to support the substrate coated with the perovskite film.

[0050] The present invention designs a hidden exhaust pipeline 3 to evenly distribute the exhaust area to all directions of the substrate coated with the perovskite film, thereby avoiding fluctuations in the air flow in the inner cavity 6, reducing the impact on the crystallization rate and uniformity of the perovskite on the substrate, and effectively improving the difference in crystallization rate and quality of the perovskite in different areas caused by the offset position of the exhaust port 5, balancing the pressure distribution in the inner cavity 6, and avoiding the occurrence of uneven pressure.

[0051] Furthermore, the cavity has a feed port and a discharge port for inputting and outputting substrates coated with perovskite thin films.

[0052] Furthermore, the base 2 is a positive U-shaped structure, corresponding to the flash cover 1 of an inverted U-shaped structure.

[0053] Furthermore, the thickness of the hidden exhaust pipeline 3 is 30-100 mm, for example, 30 mm, 40 mm, 50 mm, 60 mm or 100 mm, etc.; wherein the thickness direction of the hidden exhaust pipeline 3 is the same as the thickness direction of the side wall of the flash cover 1.

[0054] In the present invention, the hidden exhaust pipeline 3 of appropriate thickness can make the airflow inside the equipment more stable and smooth, avoiding the airflow vortex and turbulence that may be generated by the exposed pipeline; secondly, the hidden exhaust pipeline can reduce the impact of the external environment on the exhaust system, help maintain the efficient operation of the exhaust system, and improve the stability and repeatability of the vacuum degree; finally, it avoids the operator from accidentally touching the exposed high-temperature or high-pressure pipeline, reduces the risk of safety accidents such as burns and scratches, and also improves the operating safety of the equipment.

[0055] Furthermore, along the direction from the air extraction port 5 to the air outlet, the width of the hidden air extraction pipeline 3 decreases gradually. Figure 4 As shown; wherein, the width direction of the hidden exhaust pipeline 3 is perpendicular to the thickness direction of the hidden exhaust pipeline 3.

[0056] In the present invention, along the direction from the vacuum port 5 to the air outlet, the width of the hidden vacuum pipeline 3 shows a decreasing trend. This design is conducive to evenly dispersing the vacuum airflow to all directions of the film, effectively improving the crystallization uniformity of the perovskite; secondly, it greatly improves the vacuum efficiency and avoids the phenomenon of insufficient suction force of the vacuum system.

[0057] Furthermore, each side wall of the flash cover 1 has at least one side wall gas outlet 4, for example, there may be 2, 3, 4 or 5 side wall gas outlets.

[0058] Furthermore, the side wall air outlet 4 is circular, with a diameter of 30-100 mm, for example, 30 mm, 40 mm, 50 mm, 60 mm, 80 mm or 100 mm, etc.

[0059] Furthermore, the air outlet 4 on the side wall of the flash cover 1 and the air suction port 5 on the open end of the side wall of the flash cover 1 are not on the same horizontal plane.

[0060] Furthermore, the air suction port 5 at the open end of the side wall of the flash cover 1 is located at a side of the open end of the side wall of the flash cover 1 close to the inner cavity 6 and is parallel to the horizontal reference plane.

[0061] It should be noted that the horizontal reference plane refers to an ideal plane parallel to the placement plane of the base 2.

[0062] Furthermore, the width of the open-end air suction port 5 is smaller than the thickness of the side wall of the flash cover 1 on the same side, and the length of the open-end air suction port 5 is equal to the length of the side wall of the flash cover 1 on the same side.

[0063] Furthermore, the vacuum device includes a vacuum pump, a vacuum pipeline and a vacuum valve.

[0064] The vacuum pump is connected to the side wall air outlet 4 of the flash cover 1 through the vacuum pipeline. The vacuum valve is arranged on the vacuum pipeline to adjust the exhaust speed of the hidden exhaust pipeline 3.

[0065] In another specific embodiment, the present invention provides a method for preparing a perovskite film, the method using the vacuum flash evaporation apparatus as described above, comprising the following steps:

[0066] The substrate coated with the perovskite precursor film is placed on a carrier device.

[0067] The parameters of the vacuum flash evaporation equipment are set, and then the vacuum device and the heating device are started to perform vacuum flash evaporation. After the completion, the obtained perovskite film is taken out.

[0068] Example 1

[0069] This embodiment provides a method for preparing a perovskite film, the method using the vacuum flash evaporation equipment as described above, comprising the following steps:

[0070] (1) Placing a substrate coated with a perovskite precursor film on a supporting device.

[0071] The chemical formula of the perovskite precursor film is Cs0.05 FA 0.8 MA 0.15 PbI 0.85 Br 0.15 .

[0072] (2) Setting the parameters of the vacuum flash evaporation equipment, and then starting the vacuum device and the heating device to perform vacuum flash evaporation. After completion, taking out the obtained perovskite film, the film thickness is 350 nm.

[0073] Specifically, the setting parameters of the vacuum flash evaporation equipment include: the inner cavity vacuum degree is 5Pa, and the drying time is 80s.

[0074] Specifically, in the vacuum flash evaporation equipment, the exhaust speed of the hidden exhaust pipeline is 800 sccm.

[0075] Example 2

[0076] This embodiment provides a method for preparing a perovskite film, the method using the vacuum flash evaporation equipment as described above, comprising the following steps:

[0077] (1) Placing a substrate coated with a perovskite precursor film on a supporting device.

[0078] The chemical formula of the perovskite precursor film is Cs 0.05 FA 0.8 MA 0.15 PbI 0.85 Br 0.15 .

[0079] (2) Setting the parameters of the vacuum flash evaporation equipment, and then starting the vacuum device and the heating device to perform vacuum flash evaporation. After completion, taking out the obtained perovskite film, the film thickness is 400 nm.

[0080] Specifically, the setting parameters of the vacuum flash evaporation equipment include: the inner cavity vacuum degree is 10Pa, and the drying time is 80s.

[0081] Specifically, in the vacuum flash evaporation equipment, the exhaust speed of the hidden exhaust pipeline is 700 sccm.

[0082] Example 3

[0083] This embodiment provides a method for preparing a perovskite film, the method using the vacuum flash evaporation equipment as described above, comprising the following steps:

[0084] (1) Placing a substrate coated with a perovskite precursor film on a supporting device.

[0085] The chemical formula of the perovskite precursor film is Cs 0.05 FA 0.8 MA0.15 PbI 0.85 Br 0.15 .

[0086] (2) Setting the parameters of the vacuum flash evaporation equipment, and then starting the vacuum device and the heating device to perform vacuum flash evaporation. After completion, taking out the obtained perovskite film, the film thickness is 350 nm.

[0087] Specifically, the setting parameters of the vacuum flash evaporation equipment include: the inner cavity vacuum degree is 1Pa, and the drying time is 120s.

[0088] Specifically, in the vacuum flash evaporation equipment, the exhaust speed of the hidden exhaust pipeline is 1000 sccm.

[0089] Example 4

[0090] The difference between this embodiment and embodiment 1 is that the exhaust speed of the hidden exhaust pipeline is 500 sccm.

[0091] The remaining methods and parameters remain the same as in Example 1.

[0092] Example 5

[0093] The difference between this embodiment and embodiment 1 is that the exhaust speed of the hidden exhaust pipeline is 2000 sccm.

[0094] The remaining methods and parameters remain the same as in Example 1.

[0095] Comparative Example 1

[0096] The difference between this comparative example and Example 1 is that each side wall of the flash evaporation cover is not provided with a hidden exhaust pipeline, and an exhaust pipeline is opened on the top of the flash evaporation cover for exhausting air.

[0097] The remaining methods and parameters remain the same as in Example 1.

[0098] Performance Testing

[0099] The perovskite films prepared in the above-mentioned embodiments and comparative examples were tested for crystal uniformity, and the specific testing methods included scanning electron microscopy and XRD diffraction.

[0100] The test results are shown in Table 1.

[0101] Table 1

[0102]

[0103]

[0104] analyze:

[0105] By comparing Example 1 with Examples 4-5, it can be seen that if the exhaust speed of the hidden exhaust pipeline is too low, the solvent cannot be effectively removed quickly, resulting in more solvent remaining in the film, which is not conducive to the crystallization speed and quality of the perovskite; if the exhaust speed of the hidden exhaust pipeline is too high, huge air flow disturbances will be generated in the chamber, which is not conducive to the stable crystallization of the perovskite.

[0106] By comparing Example 1 with Comparative Example 1, it can be seen that if an exhaust pipeline is opened on the top of the flash evaporation cover, the air flow speed in the cavity will be faster, which may cause certain disturbances to the growth of the perovskite film and affect the longitudinal growth of the perovskite film.

[0107] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A vacuum flash evaporation device for preparing perovskite thin film, characterized in that: It includes a cavity, a vacuum device, a heating device and a carrying device; The cavity comprises a flash cover and a base arranged up and down, and the flash cover is an inverted U-shaped structure; each side wall of the flash cover is provided with a hidden exhaust pipeline, one end of the hidden exhaust pipeline extends to and passes through the air outlet of the side wall of the flash cover, and the other end of the hidden exhaust pipeline extends and passes through the exhaust port at the open end of the side wall of the flash cover, and is connected with the inner cavity of the cavity; The vacuum device is located outside the cavity, and is connected to the side wall air outlet of the flash cover through a vacuum pipeline for exhausting air; the heating device is used to provide heat to the cavity to promote rapid evaporation of the solvent in the perovskite film; the supporting device is connected to the base and is used to support the substrate coated with the perovskite film.

2. The vacuum flash evaporation equipment according to claim 1, characterized in that: The cavity has a feed port and a discharge port for inputting and outputting the substrate coated with the perovskite film; Preferably, the base is a positive U-shaped structure, corresponding to the flash cover of an inverted U-shaped structure.

3. The vacuum flash evaporation equipment according to claim 1 or 2, characterized in that: The thickness of the hidden exhaust pipeline is 30-100 mm; wherein the thickness direction of the hidden exhaust pipeline is the same as the thickness direction of the side wall of the flash cover; Preferably, along the direction from the air extraction port to the air outlet, the width of the hidden air extraction pipeline shows a decreasing trend; wherein, the width direction of the hidden air extraction pipeline is perpendicular to the thickness direction of the hidden air extraction pipeline.

4. The vacuum flash evaporation equipment according to any one of claims 1 to 3, characterized in that: Each side wall of the flash cover has at least one side wall air outlet; Preferably, the side wall gas outlet is circular with a diameter of 30-100 nm.

5. The vacuum flash evaporation equipment according to any one of claims 1 to 4, characterized in that: The air outlet of the side wall of the flash cover and the air extraction port at the open end of the side wall of the flash cover are not in the same horizontal plane; Preferably, the air extraction port at the open end of the side wall of the flash cover is located on a side of the open end of the side wall of the flash cover close to the inner cavity and is parallel to the horizontal reference plane.

6. The vacuum flash evaporation equipment according to any one of claims 1 to 5, characterized in that: The width of the open end suction port is smaller than the thickness of the side wall of the flash cover on the same side, and the length of the open end suction port is equal to the length of the side wall of the flash cover on the same side.

7. The vacuum flash evaporation equipment according to any one of claims 1 to 6, characterized in that: The vacuum device comprises a vacuum pump, a vacuum pipeline and a vacuum valve; The vacuum pump is connected to the air outlet of the side wall of the flash cover through the vacuum pipeline, and the vacuum valve is arranged on the vacuum pipeline to adjust the exhaust speed of the hidden exhaust pipeline.

8. A method for preparing a perovskite film, characterized in that: The method uses the vacuum flash evaporation equipment according to any one of claims 1 to 7, comprising the following steps: placing a substrate coated with a perovskite precursor film on a carrier device; The parameters of the vacuum flash evaporation equipment are set, and then the vacuum device and the heating device are started to perform vacuum flash evaporation. After the completion, the obtained perovskite film is taken out.

9. The method according to claim 8, characterized in that The setting parameters of the vacuum flash evaporation equipment include: The vacuum degree of the inner cavity is 1×10 -2 -1×10 2 Pa, drying time is 20-150s; Preferably, in the vacuum flash evaporation equipment, the exhaust speed of the hidden exhaust pipeline is 500-2000sccm.

10. The method according to claim 8 or 9, characterized in that: The chemical formula of the perovskite precursor film is ABX3, wherein A is any one of formamidinium ion, methylamine ion or cesium ion or a combination of at least two thereof, B is lead ion and / or tin ion, and X is a halogen ion; Preferably, the thickness of the perovskite film is 300-650 nm; Preferably, the grain boundary density of the perovskite film is 1×10 8 -1×10 10 cm -2 .

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