Roller coating device and method for perovskite thin film

Abstract

The invention provides a roller coating device and method for a perovskite thin film, and relates to the technical field of photovoltaics. The roller coating device for the perovskite thin film comprises a roller coating assembly, a conveying assembly and a film uniformizing assembly. The conveying assembly is used for fixing and conveying the substrate; the roller coating assembly is used for carrying out roller coating on a perovskite liquid film on the first surface of the substrate; the substrate is provided with a roller coating starting end and a roller coating ending end; the membrane uniformizing assembly comprises a solvent tank and a first scraper; the first scraper is used for scraping the thickness of the perovskite liquid film at the roller coating ending end; at least part of the first scraper is immersed in the perovskite solvent in the solvent tank, and the perovskite solvent is used for dissolving the perovskite liquid film remaining on the first scraper. According to the invention, the thickness uniformity of the perovskite thin film is improved.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic technology, and in particular to a roll coating apparatus and method for perovskite thin films. Background Technology

[0002] In recent years, the photoelectric conversion efficiency of perovskite solar cells has been continuously improving, and has long since broken through the theoretical limit of crystalline silicon cells. How to achieve the mass production of perovskite solar cells, especially the mass production of perovskite thin films, is now the focus of industry attention.

[0003] Currently, the main methods for preparing perovskite thin films include spin coating, slot coating, evaporation, and blade coating.

[0004] However, spin coating and blade coating are difficult to use for large-area coating. Slit coating requires extremely high precision in terms of blade flatness and alignment for large-area coating, resulting in high equipment costs and hindering large-scale, high-capacity deployment. Evaporation methods also have high equipment and raw material costs, which is not conducive to large-scale industrialization. Summary of the Invention

[0005] This invention provides a roll coating apparatus and method for perovskite thin films, aiming to solve the problem of the difficulty in mass-producing perovskite thin films.

[0006] A first aspect of the present invention provides a roll coating apparatus for perovskite thin films, comprising:

[0007] Roll coating assembly, conveying assembly and film leveling assembly;

[0008] The conveying component is used to fix and convey the base;

[0009] The roll coating assembly is used to roll coat a perovskite liquid film onto a first surface of a substrate; the substrate has a roll coating start end and a roll coating end end.

[0010] The film coating assembly includes: a solvent tank and a first scraper; the solvent tank contains perovskite solvent; the first scraper is used to reduce the thickness of the perovskite liquid film located at the end of the roll coating; at least a portion of the first scraper is submerged in the perovskite solvent in the solvent tank, and the perovskite solvent is used to dissolve the perovskite liquid film remaining on the first scraper.

[0011] In this embodiment of the invention, the roll coating assembly of the roll coating device achieves roll coating of a perovskite liquid film onto the first surface of the substrate. Roll coating is simple to implement and has a high speed, making it easy to achieve large-area mass production of perovskite thin films. Simultaneously, the roll coating device is relatively simple, effectively reducing equipment investment costs and subsequent raw material usage costs. Addressing the common problem in roll coating where the thickness of the perovskite liquid film at the end of the roll coating is greater than that at other locations, or a tailing phenomenon, this application includes a film leveling assembly after roll coating. A first scraper is used to scrape down the thickness of the perovskite liquid film at the end of the roll coating on the substrate, thereby reducing the thickness of the perovskite liquid film at the end of the roll coating and making the thickness of the perovskite liquid film at various locations on the first surface of the substrate approximately equal, which can improve the performance of the formed perovskite solar cell. After scraping down, the first scraper is immersed in the perovskite solvent in the solvent tank, where the perovskite solvent is used to dissolve the remaining perovskite liquid film or perovskite accumulation on the first scraper. In summary, this application solves the trailing problem and improves the uniformity of the thickness of the perovskite film at various locations on the first surface of the substrate.

[0012] In some embodiments, the conveying assembly includes: a guide rail, a first motor, a second motor, and a third motor disposed on the guide rail, and an adsorption mechanism connected to the first motor, the second motor, and the third motor; the adsorption mechanism is used to adsorb and fix a substrate, the first motor is used to drive the adsorption mechanism to move along a first direction, the second motor is used to drive the adsorption mechanism to move along a second direction, and the third motor is used to rotate the adsorption mechanism; the first direction is different from the second direction;

[0013] In the second direction, the scraping position of the first scraper is further away from the adsorption mechanism than the rolling position of the roller coating assembly.

[0014] In some embodiments, the uniform coating assembly further includes a second scraper for controlling the amount of perovskite solvent remaining on the first scraper; the second scraper is located between the scraping position of the first scraper and the solvent tank.

[0015] In some embodiments, the projection of the contact position of the first scraper and the second scraper in the direction of gravity is located within the solvent tank.

[0016] In some embodiments, the first scraper includes one of: a film-spreading roller, a scraper, a scraper blade, and a wiping cloth;

[0017] The second scraper includes one of the following: a scraper blade, a scraper knife, or a wiping cloth.

[0018] In some embodiments, the material of the second scraper is selected from at least one of plastic and rubber.

[0019] In some embodiments, the roll coating assembly includes: a perovskite solution tank, a third scraper, and a roll coating roller; the perovskite solution tank contains a perovskite solution; the third scraper and the roll coating roller are spaced apart.

[0020] In the rotation direction of the coating roller, the third scraper is located between the perovskite solution tank and the coating position.

[0021] In some embodiments, the projection of the position of the third scraper adjacent to the coating roller in the direction of gravity is located within the perovskite solution tank.

[0022] In some embodiments, the third scraper includes one of: a scraper blade, a scraper knife, and a wiping cloth;

[0023] The material of the third scraper is selected from at least one of plastic and rubber.

[0024] In some embodiments, the number of the roll coating assemblies is greater than or equal to 2, and each of the roll coating assemblies is arranged sequentially along the direction of movement of the substrate during the roll coating process.

[0025] In some embodiments, the adsorption mechanism includes an adsorption surface, and the conveying assembly further includes a fourth motor disposed on the guide rail, the adsorption mechanism and the fourth motor being connected, and the fourth motor being used to drive the adsorption surface of the adsorption mechanism to rotate.

[0026] In some embodiments, the perovskite thin film roll coating apparatus further includes: a housing located outside the conveying assembly, the roll coating assembly, and the uniform coating assembly, and an atmosphere conditioning assembly located outside the housing; the housing is provided with a feed inlet, a discharge outlet, and a gas inlet;

[0027] The atmosphere conditioning assembly includes: a cooler, and a pipe passing through the cooler, the pipe being connected to the housing via the gas inlet; an inert gas is introduced into the pipe.

[0028] In some embodiments, the conveying assembly includes: a drive cone wheel located at least between the uniform coating assembly and the discharge port; the drive cone wheel includes: a bearing ramp near the roller coating position, the drive cone wheel bearing a substrate passing through the uniform coating assembly via the bearing ramp, the perovskite liquid film on the substrate being close to the bearing ramp, and conveying the substrate to the outside of the housing.

[0029] In some embodiments, a bearing groove is provided on the bearing inclined surface for limiting the end of the substrate.

[0030] In some embodiments, the perovskite thin film roll coating apparatus further includes an air knife assembly located after the uniform film assembly within the housing, the air knife assembly being used to blow compressed air toward a first surface of the substrate.

[0031] A second aspect of the present invention provides a roll coating method for perovskite thin films, comprising:

[0032] Fix and transfer the base;

[0033] A perovskite liquid film is roll-coated onto the first surface of the substrate; the substrate includes: a roll-coating start end and a roll-coating end end;

[0034] The thickness of the perovskite liquid film located at the end of the roll coating is reduced by using a first scraper.

[0035] In some embodiments, after roller coating, the method described above further includes:

[0036] The substrate is rotated such that, in the second direction, the end of the roll coating on the substrate is closer to the first scraper than the beginning of the roll coating on the substrate, and the angle between the first surface of the substrate and the first direction is 0.1° to 20°; the first direction is different from the second direction.

[0037] The scraping step includes:

[0038] During the movement of the substrate along the first direction, the thickness of the perovskite liquid film located at the end of the roll coating is reduced using the first scraper.

[0039] In some embodiments, the roller coating step includes at least one of the following steps:

[0040] When the substrate moves along a first direction, and the angle between the first surface of the substrate and the first direction is less than or equal to a first preset angle, and the distance between the first surface of the substrate and the roller coating position remains constant, a perovskite liquid film is roller coated on the first surface of the substrate.

[0041] When the substrate moves along a first direction and a second direction, and the angle between the first surface of the substrate and the first direction is greater than a first preset angle, and the distance between the first surface of the substrate and the roller coating position remains constant, a perovskite liquid film is roller coated on the first surface of the substrate.

[0042] When the substrate moves along a first direction, the angle between the first surface of the substrate and the first direction is less than or equal to a first preset angle, the distance between the first surface of the substrate and the roller coating position remains constant, and the roller coating start end and roller coating end end are both located on the diagonal of the first surface, a perovskite liquid film is roller coated on the first surface of the substrate.

[0043] Wherein, the first preset angle is equal to 20°.

[0044] In some embodiments, the roller coating step includes:

[0045] The first surface of the substrate is subjected to multiple roll coatings.

[0046] In some embodiments, during the roll coating process: the distance between the first surface of the substrate and the roll coating position is 1 μm to 200 μm, and / or, during the roll coating process: the movement speed of the substrate is 10 mm / s to 150 mm / s.

[0047] In some embodiments, the roller coating step includes:

[0048] During the uniform motion of the substrate along the first direction, a perovskite liquid film is rolled onto the first surface of the substrate.

[0049] In some embodiments, the roll coating method for the perovskite film is applied in any of the roll coating apparatuses for the aforementioned perovskite films.

[0050] In some embodiments, the uniform film assembly includes: a first scraper; after the scraping step, the method further includes:

[0051] The first scraper is immersed in the perovskite solvent, and the perovskite solvent dissolves the perovskite liquid film remaining on the first scraper;

[0052] Control the amount of perovskite solvent remaining on the first scraper.

[0053] In some embodiments, the film-leveling assembly includes: a film-leveling roller; the scraping step includes:

[0054] The rotation direction of the scraping position of the uniform film roller is controlled to be opposite to the movement direction of the substrate, so as to scrape down the thickness of the perovskite liquid film located at the end of the roll coating.

[0055] In some embodiments, the roll coating assembly includes: prior to roll coating by roll coating rollers, the method further includes:

[0056] With the first surface of the substrate facing the uniform coating roller, the substrate is controlled to remain stationary for a preset time, and the coating roller continues to rotate within the preset time to accumulate perovskite solution between the substrate and the coating roller; the preset time is from 1 second to 120 seconds.

[0057] In some embodiments, controlling the substrate to remain stationary for a preset duration includes:

[0058] When the distance between the first surface of the substrate and the roller coating roller is less than a first distance, the substrate is controlled to remain stationary for a first preset duration; the first preset duration is from 1 second to 60 seconds.

[0059] When the distance between the first surface of the substrate and the roller coating roller is greater than the first distance, the substrate is controlled to remain stationary for a second preset duration; the second preset duration is from 1 second to 60 seconds.

[0060] The roller coating step includes:

[0061] When the distance between the first surface of the substrate and the coating roller is equal to the first distance, the perovskite liquid film is coated onto the first surface of the substrate using the uniform coating roller. Attached Figure Description

[0062] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0063] Figures 1 to 5 Several front view schematic diagrams of the roll coating apparatus for the perovskite thin film provided in this application;

[0064] Figure 6 A partial front view of the roller coating assembly and the substrate during the roller coating process provided in this application;

[0065] Figure 7 This is a schematic diagram showing the thickness distribution of the perovskite liquid film at different locations on the substrate during the roll coating process, assuming the substrate is not stationary before roll coating.

[0066] Figure 8 A frontal view of the distribution of perovskite liquid film at different locations in the substrate obtained by roller coating when the substrate is not stationary before roller coating.

[0067] Figures 9 to 10 Several front view schematic diagrams of the transmission cone wheel provided in this application.

[0068] Attached image annotations:

[0069] 1-Roller coating assembly, 2-Conveying assembly, 3-Film leveling assembly, 110-Perovskite solution tank, 120-Roller coating roller No. 1, 121-Roller coating roller No. 2, 130-Third scraper No. 1, 131-Third scraper No. 2, 140-Perovskite solution, 141-Perovskite liquid film, 142-Perovskite liquid accumulation, 21-Guide rail, 22-Adsorption mechanism, 23-First motor, 24-Second motor, 310-Solvent tank, 320-Film leveling roller, 330-Second scraper, 340-Perovskite solvent, 40-Substrate, 500-Outer shell, 510-Inlet, 520-Outlet, 530-Pipe, 531, 532-Gas inlet, 540-Cooler, 600-Drive cone wheel, 610-Bearing inclined surface of drive cone wheel near the roller coating position. Detailed Implementation

[0070] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0071] This invention provides a roll coating apparatus for perovskite thin films, with reference to... Figure 1 The perovskite film roll coating apparatus may include: roll coating assembly 1, conveying assembly 2 and film leveling assembly 3.

[0072] Reference Figures 1 to 5The conveying component 2 is used to fix and convey the substrate 40. Here, the substrate refers to the material on which the perovskite thin film is to be deposited; however, in this application, the substrate is not limited. For example, for a single perovskite solar cell, the substrate can be at least one of conductive glass, an electron transport layer, a hole transport layer, a polymer film, a metal foil, or a flexible metal. For tandem cells, perovskite solar cells have an advantage in short-wavelength absorption compared to crystalline silicon solar cells; therefore, the perovskite solar cell may be positioned closer to the light-facing side. The substrate here can be the substrate of the aforementioned single perovskite solar cell superimposed on a crystalline silicon solar cell. The roll coating component 1 is used to roll coat the first surface of the substrate 40 with a perovskite liquid film 141. After the perovskite liquid film 141 is cured, a perovskite thin film is obtained. First, the substrate 40 is fixed and conveyed by the conveying component 2, so that the first surface of the substrate 40 is opposite to the roll coating component 1. The roll coating component 1 roll coats the first surface of the substrate 40 with a perovskite liquid film 141. The roll coating method is simple and fast, making it easy to achieve large-area mass production of perovskite films. At the same time, the roll coating device is relatively simple, which can effectively reduce equipment investment costs and subsequent raw material usage costs. The first surface of the substrate 40 refers to one or more surfaces on the substrate where the perovskite film is to be deposited; the specific surface(s) are not limited. The substrate 40 has a roll coating start end and a roll coating end end. The roll coating start end refers to the end from which the roll coating of the substrate 40 begins, and the roll coating end refers to the end from which the roll coating of the substrate 40 ends. The roll coating start end and roll coating end end are usually related to the direction of movement of the substrate 40 during the roll coating process. For example, Figures 1 to 6 In the process of roller coating, the substrate 40 moves from left to right along the first direction L1. Therefore, the starting end of roller coating is the rightmost end of the substrate 40, and the ending end of roller coating is the leftmost end. Figure 6 In the image, the arrow indicates the direction of motion of the base.

[0073] Reference Figures 1 to 6 The principle of roll coating is as follows: a perovskite solution 140 of uniform thickness is distributed on the surface of the roll coating roller. Through the relative movement between the roll coating roller and the substrate 40, the perovskite solution 140 on the surface of the roll coating roller is transferred to the first surface of the substrate 40. The thickness of the perovskite liquid film 141 obtained by roll coating can be adjusted by changing the concentration of the perovskite solution 140 and the distance between the substrate and the roll coating roller. For the perovskite solution 140 to transfer onto the substrate 40, the substrate 40 must be in full contact with the perovskite solution 140 on the surface of the roll coating roller, i.e., refer to... Figure 6 The distance between the substrate 40 and the roll coating roller must be less than the thickness of the perovskite solution on the surface of the roll coating roller. The inventors discovered that this leads to a problem: excess perovskite solution on the roll coating roller accumulates between the roll coating roller and the substrate during the roll coating process. (See reference...) Figure 7 and Figure 8 When the substrate is not stationary before roll coating, in the initial stage of roll coating, the perovskite solution accumulated between the roll coating roller and the substrate 40 gradually increases, eventually reaching a stable value. At this point, the amount of accumulated perovskite solution balances the amount of perovskite solution escaping from the roll coating roller. At the end of roll coating, when the roll coating end of the substrate 40 leaves the roll coating roller, this accumulated perovskite solution remains at the roll coating end of the substrate 40 due to its own surface tension. Furthermore, over time, the larger amount of perovskite solution at the roll coating end of the substrate 40 gradually diffuses towards the center of the substrate. This results in a situation where the perovskite liquid film is thinner at the beginning of the roll coating, more uniform in the middle stage, and thicker at the end of the roll coating (e.g., ...). Figure 8 This uneven thickness results in a perovskite film with a thinner initial coating, a more uniform thickness in the middle, and a thicker final coating. Specifically, the perovskite liquid film at the final coating point on the substrate 40 is typically thicker than the films at other locations. This unevenness leads to variations in light absorption and carrier separation capabilities across the perovskite film, significantly impacting the performance of perovskite solar cells. In particular, the performance degradation caused by the thicker perovskite film at the final coating point is likely more pronounced. The inventors discovered that while adjusting the substrate travel speed at different stages of the coating process can mitigate this unevenness, it cannot fundamentally solve the problem. Furthermore, precisely controlling the substrate travel speed at different stages is difficult.

[0074] To address the aforementioned technical problems, the perovskite thin film roll coating apparatus of this application employs a film leveling component after the perovskite liquid film is formed during roll coating to reduce the thickness of the perovskite liquid film located at the end of the roll coating process. Specifically, refer to... Figures 1 to 5The uniform coating assembly 3 includes a solvent tank 310 and a first scraper. The solvent tank 310 contains a perovskite solvent 340, which can dissolve the perovskite liquid film. The perovskite solvent 340 is a good solvent for perovskite materials, and the specific material is not limited. For example, the perovskite solvent 340 can be DMF (N,N-dimethylformamide), DMSO (N,N-dimethylformamide), NMP (N-methylpyrrolidone), etc. The first scraper is used to reduce the thickness of the perovskite liquid film at the end of the roll coating on the substrate 40. At least a portion of the first scraper is immersed in the perovskite solvent 340 in the solvent tank 310. After reducing the thickness, the first scraper remains immersed in the perovskite solvent 340 in the solvent tank 310. The perovskite solvent 340 is used to dissolve the remaining perovskite liquid film or perovskite accumulation 142 on the first scraper. The coated substrate is conveyed by the conveying component 2 to the location opposite the uniform coating component 3. Then, the first scraper of the uniform coating component 3 scrapes down the thickness of the perovskite liquid film at the end of the roll coating, thereby making the thickness of the perovskite liquid film 141 at various locations on the first surface of the substrate 40 approximately equal. This results in a perovskite thin film with approximately equal thickness at various locations, improving the performance of the formed perovskite solar cell. In summary, this application solves the tailing problem and improves the uniformity of the perovskite thin film thickness at various locations on the first surface of the substrate. The perovskite solar cell here can refer to a single perovskite solar cell or a perovskite solar cell in a tandem cell.

[0075] In some embodiments, the above-mentioned uniform film assembly further includes a second scraper 330, located between the scraping position of the first scraper and the solvent tank 310. The second scraper 330 is used to control the amount of perovskite solvent remaining on the first scraper, preventing excessive contact between the residual perovskite solvent on the first scraper and the perovskite liquid film 141 on the substrate 40, thus affecting the quality of the formed perovskite film. In other words, this application not only solves the tailing problem and improves the uniformity of the perovskite film thickness at various locations on the first surface of the substrate, but also avoids the impact on the perovskite film at other locations during the process of solving the tailing problem. For example, the second scraper here can remove the residual perovskite solvent on the first scraper, preventing the residual perovskite solvent on the first scraper from contacting the perovskite liquid film 141 on the substrate 40.

[0076] In some embodiments, refer to Figures 1 to 5The conveying assembly 2 includes: a guide rail 21, a first motor 23, a second motor 24, and a third motor (not shown) mounted on the guide rail 21, and an adsorption mechanism 22 connected to all three motors. The adsorption mechanism 22 is used to adsorb and fix the substrate 40. The adsorption mechanism 22 can adsorb the substrate 40 below it through vacuum adsorption or electrostatic adsorption, etc. The specific form of the adsorption mechanism 22 is not limited. The first motor 23 drives the adsorption mechanism 22 to move along a first direction L1, and the second motor 24 drives the adsorption mechanism 22 to move along a second direction L2. The first direction L1 is different from the second direction L2, and the included angle between them is not limited; for example, they can be perpendicular to each other. (Refer to...) Figure 2 The third motor is used to rotate the adsorption mechanism 22 so that, in the second direction L2, the end of the roller coating of the substrate 40 is closer to the uniform film assembly 3 than the beginning of the roller coating of the substrate 40, and the angle α between the first surface of the substrate 40 and the first direction L1 is 0.1° to 20°. When the first surface of the substrate 40 is planar, the angle α between the first surface of the substrate 40 and the first direction L1 is the angle between the two; when the first surface of the substrate 40 is curved, the first surface of the substrate 40 can be considered as the extension direction of the first surface of the substrate 40, and the angle α here can be considered as the angle between the extension direction of the first surface of the substrate 40 and the first direction L1. Since the adsorption mechanism 22 adsorbs and fixes the substrate 40 here, the driving action of the first motor 23, the second motor 24, and the third motor on the adsorption mechanism 22 is equivalent to the driving action on the substrate 40. Meanwhile, referring to... Figure 2 In the second direction L2, the position where the first scraper in the uniform film assembly 3 reduces the thickness of the perovskite liquid film 141 is further away from the adsorption mechanism 22 than the rolling position of the roll coating assembly 1. The position where the first scraper in the uniform film assembly 3 reduces the thickness of the perovskite liquid film 141 can be considered as: along the second direction L2, the position where the first scraper in the uniform film assembly 3 is closest to the substrate 40 or the adsorption mechanism 22. The rolling position of the roll coating assembly 1 can be considered as: along the second direction L2, the position in the roll coating assembly 1 closest to the substrate 40 or the adsorption mechanism 22.

[0077] Specifically, refer to Figure 2After the third motor rotates the adsorption mechanism 22, in the second direction L2, the end of the roll coating of the substrate 40 is closer to the uniform coating assembly 3 than the beginning of the roll coating of the substrate 40. Furthermore, the position where the first scraper in the uniform coating assembly 3 reduces the thickness of the perovskite liquid film 141 is further away from the adsorption mechanism of the substrate 40 than the roll coating position of the roll coating assembly 1. Simultaneously, the angle α between the first surface of the substrate 40 and the first direction L1 is 0.1° to 20°. During the movement of the substrate 40 along the first direction L1 controlled by the first motor 23, the first scraper in the uniform coating assembly 3 reduces the excess thickness of the perovskite liquid film located at the end of the roll coating. That is to say, during the uniform coating process, the substrate 40 no longer moves towards the uniform coating assembly 3 along the second direction L2. Therefore, the portion of the substrate 40 other than the end of the roll coating will not be affected by the adsorption mechanism. In the homogenizing assembly 3, the first scraper contacts the position where the thickness of the perovskite liquid film 141 is reduced. Only the thicker portion of the perovskite liquid film 141 at the end of the roll coating on the substrate 40 comes into contact with the position where the first scraper reduces the thickness of the perovskite liquid film 141 in the homogenizing assembly 3, and part of the film thickness is carried away by the homogenizing assembly 3. That is to say, during the homogenizing process, the perovskite liquid film 141 outside the end of the roll coating on the substrate 40 is not affected, avoiding material waste. Only the excess perovskite liquid film 141 at the end of the roll coating on the substrate 40 is cleaned up. After cleaning the excess perovskite liquid film 141 at the end of the roll coating on the substrate 40, a complete and uniform perovskite liquid film is formed on the first surface of the substrate 40. This forms a complete and uniform perovskite thin film by curing on the first surface of the substrate 40. During the homogenizing process, the distance between the end of the roll coating on the substrate 40 and the position where the first scraper reduces the thickness of the perovskite liquid film 141 in the homogenizing assembly 3 is flexibly adjusted through the participation of the third motor. By adjusting the included angle of rotation of substrate 40, the height difference between the roller coating position of roller coating assembly 1 and the position where the first scraper in uniform film assembly 3 reduces the thickness of perovskite liquid film 141, and the distance between the end of roller coating in substrate 40 and the position where the first scraper in uniform film assembly 3 reduces the thickness of perovskite liquid film 141, the excess perovskite liquid film 141 at the end of roller coating in substrate 40 is effectively cleaned without affecting the thickness of perovskite liquid film 141 outside the end of roller coating in substrate 40, thus avoiding material waste. The overall thickness of the perovskite liquid film is relatively uniform, further improving the performance of perovskite solar cells. Moreover, during the uniform film process, only the first motor 23 needs to be controlled, making the operation simple and easy to implement.

[0078] It should be noted that the included angle α here is between 0.1° and 20°. If the included angle α is less than 0.1°, during the homogenization process, the perovskite liquid film 141 outside the end of the roll coating in the substrate 40 may come into contact with the position where the first scraper in the homogenization assembly 3 scrapes down the thickness of the perovskite liquid film, which may easily affect the thickness of the perovskite liquid film 141 outside the end of the roll coating in the substrate 40. If the included angle α is too small, it may cause the excess perovskite liquid film at the end of the roll coating in the substrate 40 to not be completely removed. If the included angle α is greater than 20°, it may cause too much perovskite liquid film to be removed from the end of the roll coating in the substrate 40, resulting in a thinner perovskite liquid film at the end of the roll coating in the substrate 40. Therefore, in this application, the included angle α here is between 0.1° and 20°, which not only does not affect the thickness of the perovskite liquid film 141 outside the end of the roll coating in the substrate 40, but also can remove the excess perovskite liquid film 141 at the end of the roll coating in the substrate 40.

[0079] For example, the included angle α here can be 0.1°, 0.5°, 0.8°, 1°, 1.2°, 1.5°, 1.8°, 2°, 2.3°, 2.5°, 2.8°, 3°, 3.2°, 3.5°, 3.9°, 4°, 4.2°, 4.5°, 4.7°, 5°, 6°, 8°, 10°, 10.5°, 12°, 15°, 17.5°, 19°, or 20°.

[0080] In some embodiments, refer to Figures 1 to 5 The projection of the contact position of the first and second scrapers in the direction of gravity is located in the solvent tank 310. As a result, the perovskite solvent cleaned by the second scraper 330 will flow back into the solvent tank 310 for continued use due to gravity, thus avoiding the waste of perovskite solvent.

[0081] In some embodiments, the first scraper includes one of a uniform coating roller, a scraper blade, a scraper plate, and a wiping cloth. The first scraper can take various forms and has a simple structure, making it easy to scrape away excess perovskite liquid film thickness from the end of the roller coating of the substrate 40. Furthermore, when the first scraper is a wiping cloth, the cloth has a relatively soft structure, resulting in a smoother surface of the formed perovskite liquid film. For example, refer to… Figures 1 to 5 The first scraper is a uniform film roller 320.

[0082] In some embodiments, the second scraper 330 includes one of a scraper blade, a scraper knife, and a wiping cloth. The second scraper 330 can take various forms and has a simple structure, making it easy to scrape off residual perovskite solvent from the first scraper. For example, refer to... Figures 1 to 5 The second scraper 330 is a scraper blade. Meanwhile, when the second scraper is a wiping cloth, the cloth's structure is relatively soft, causing minimal wear to the first scraper.

[0083] In some embodiments, the material of the second scraper is selected from at least one of plastic and rubber. The material has a certain degree of flexibility and is wear-resistant, and will not introduce foreign objects into the first scraper, nor will it cause any wear to the first scraper.

[0084] In some embodiments, refer to Figures 1 to 5 The first scraper is a uniform film roller 320. In the rotation direction of the uniform film roller 320, the uniform film roller 320 is submerged in the perovskite solvent 340, or in the solvent tank 310, located between the scraping position and the second scraper. Then, after the uniform film roller 320 scrapes the perovskite solvent 340 in the scraping position, as the uniform film roller 320 rotates, the uniform film roller 320 will dissolve the perovskite liquid film remaining on the uniform film roller 320. The second scraper 330 is set in contact with the uniform film roller 320. After dissolution, the second scraper controls the amount of perovskite solvent remaining on the uniform film roller 320, such as cleaning the perovskite solvent remaining on the uniform film roller 320.

[0085] It should be noted that the scraping position can refer to the closest point between the uniform film roller 320 and the adsorption mechanism 22. (See reference...) Figure 2 The uniform film roller 320 rotates counterclockwise, and the scraping position is the highest point of the uniform film roller 320.

[0086] In some embodiments, refer to Figure 2 The uniform coating assembly 3 includes a uniform coating roller 320. The rotation direction of the uniform coating roller 320 at its scraping position can be controlled to be opposite to the movement direction of the substrate 40, thereby scraping down the thickness of the perovskite liquid film 141 located at the end of the roll coating. Only reverse movement is needed to reduce the thickness of the perovskite liquid film 141 at the end of the roll coating, making the implementation simple. The rotation direction of the uniform coating roller 320 at its scraping position is the same as the rotation direction of the position where the uniform coating roller 320 is closest to the adsorption mechanism 22, for example... Figure 2 In the process, the rotation direction of the uniform film roller 320 is counterclockwise, the rotation direction of the scraping position of the uniform film roller 320 is to the left along the first direction L1, and the movement direction of the substrate 40 is to the right along the first direction L1. The two movements are opposite to each other, thereby scraping down the thickness of the perovskite liquid film 141 located at the end of the roll coating by the uniform film roller 320.

[0087] In some embodiments, refer to Figures 1 to 5The roll coating assembly 1 includes: a perovskite solution tank 110, a third scraper, and a roll coating roller. The third scraper and the roll coating roller are spaced apart, and the size of this gap is related to the thickness of the perovskite liquid film to be formed, the rotational speed of the roll coating roller, and the movement speed of the substrate, etc., and its specific size is not limited. The perovskite solution tank 110 contains a perovskite solution 140. In the rotational direction of the roll coating roller, the third scraper 130 is located between the perovskite solution tank 110 and the roll coating position. The perovskite solution 140 may contain perovskite material and a perovskite solvent for dissolving the perovskite material. Then, the roll coating roller is first immersed in the perovskite solution 140, and the roll coating roller carries the perovskite solution 140. Then, the third scraper scrapes off the excess perovskite solution 140. The roll coating roller contacts the first surface of the substrate, transferring the perovskite solution 140 to the first surface of the substrate 40 to form a perovskite liquid film 141. It should be noted that the coating position can refer to the closest point between the coating roller and the adsorption mechanism. The rotation direction of the coating roller can be the same as the movement direction during the substrate coating process. By setting a third scraper, excess perovskite solution on the surface of the coating roller is scraped away, ensuring that the perovskite solution on the surface of the coating roller maintains a certain thickness and is not affected by fluctuations in the amount of perovskite solution in the perovskite solution tank 110. When the amount of solution in the perovskite solution tank 110 fluctuates during the coating process, such as when too much perovskite solution is added, the thickness of the solution on the surface of the coating roller will change. The third scraper can ensure that the thickness of the perovskite solution on the surface of the coating roller remains constant.

[0088] In some embodiments, refer to Figures 1 to 5 The projection of the third scraper, which is adjacent to the roller coating roller, in the direction of gravity is located in the perovskite solution tank 110. As a result, the perovskite solution scraped off by the third scraper can flow back into the perovskite solution tank 110 due to gravity, thus avoiding waste of the perovskite solution.

[0089] In some embodiments, refer to Figures 1 to 5 The third scraper may also include one of the following: a scraper blade, a scraper knife, or a wiping cloth. The material of the third scraper may be selected from at least one of plastic and rubber. It has corresponding beneficial effects as the aforementioned second scraper, and to avoid repetition, these will not be elaborated upon here. For example, Figures 1 to 5 In the middle, the third scraper is a scraper blade.

[0090] In some embodiments, refer to Figure 3The number of roller coating assemblies 1 is greater than or equal to 2. Along the movement direction of the substrate 40 during the roller coating process, each roller coating assembly 1 is sequentially arranged. Each roller coating assembly 1 can be controlled independently, allowing each to work independently to sequentially perform multiple roller coatings on the first surface of the substrate 40. Specifically, uneven adhesion or small air bubbles at the roller coating positions of the roller coating assembly 1, or foreign objects or insufficient adhesion at certain locations on the first surface of the substrate, can lead to incomplete coverage of the perovskite liquid film at those locations, resulting in uneven perovskite film thickness or even short circuits. Multiple roller coating assemblies will perform at least one more roller coating after the first roller coating, thereby reducing the problems of incomplete coating or short circuits and ensuring the quality of the perovskite film coating. The number of roller coating assemblies 1 can be 2, 3, 4, etc.

[0091] It should be noted that when the number of roller coating assemblies 1 is greater than or equal to 2, there is no limitation on whether the structures of the roller coating assemblies are the same. For example, Figure 3 In this design, there are two roller coating assemblies 1, and the roller coating assemblies have the same structure, each including a third scraper (third scraper No. 1 130 and third scraper No. 2 131) and roller coating rollers (roller coating roller No. 1 120 and roller coating roller No. 2 121). At least two roller coating assemblies can share a single perovskite solution tank to minimize the space occupied by the roller coating assemblies and simplify the assembly process. It should be noted that the rotation direction of roller coating roller No. 1 120, which performs the first roller coating on the substrate 40, can be the same as the movement direction of the substrate 40 during the roller coating process. Whether the rotation direction of roller coating roller No. 2 121, which subsequently performs the first roller coating on the substrate 40, is the same as the movement direction of the substrate 40 during the roller coating process is not limited. For example, Figure 3 In the process of roller coating, the substrate 40 moves to the right along the first direction L1. The No. 1 roller coating roller 120, which performs the first roller coating on the substrate 40, rotates clockwise, and its rotation direction at the roller coating position is to the right along the first direction L1. The rotation direction of the subsequent No. 2 roller coating roller 121 at the roller coating position can be clockwise or counterclockwise.

[0092] In some embodiments, the adsorption mechanism 22 includes an adsorption surface, which is the surface closest to the substrate 40 after adsorbing the substrate 40. The conveying component 2 also includes a fourth motor (not shown in the figure) disposed on the guide rail 21. The adsorption mechanism 22 is connected to the fourth motor, which is used to drive the adsorption surface of the adsorption mechanism to rotate, thereby also driving the first surface of the substrate 40 to rotate in the adsorption substrate 40. The first motor can be controlled to drive the substrate 40 to move along the first direction L1, and the fourth motor can be controlled to drive the first surface of the substrate 40 to rotate until the angle between the first surface of the substrate 40 and the first direction L1 is less than or equal to a first preset angle, the distance between the first surface of the substrate 40 and the roller coating position remains constant, and the roller coating start end and roller coating end of the substrate 40 are both located on the diagonal of the first surface of the substrate 40. In this case, during the roller coating process, the roller coating start end and roller coating end are approximately a vertex of the substrate 40. Compared to the roller coating start end and roller coating end being an edge of the substrate 40, this method can concentrate the roller coating start end and roller coating end at a vertex instead of one side. In cases where the roller coating start end and roller coating end are prone to uneven perovskite liquid film, the part with uneven perovskite liquid film is reduced to the vertex, the area of ​​uneven perovskite liquid film is smaller, the thickness uniformity of the perovskite thin film obtained by roller coating is better, and the performance of perovskite solar cells is further improved. The first preset angle here is 20°, which means that the first surface of the substrate 40 is approximately parallel to the first direction L1 of the movement of the substrate 40. Keeping the distance between the first surface of the substrate 40 and the roller coating position constant can mean that the distance between the first surface of the substrate 40 and the roller coating position remains constant along the second direction L2.

[0093] In some embodiments, the roll coating step may include: controlling a first motor to drive a substrate 40 to move along a first direction L1; when the angle between the first surface of the substrate 40 and the first direction L1 is less than or equal to a first preset angle, and the distance between the first surface of the substrate 40 and the roll coating position remains constant, using a roll coating assembly 1 to roll coat a perovskite liquid film onto the first surface of the substrate 40. Here, the first preset angle is equal to 20°, that is, roll coating is performed when the first surface of the substrate 40 is approximately parallel to the first direction L1. The roll coating control process is simple. For example, controlling a first motor to drive a substrate 40 to move along the first direction L1; when the first surface of the substrate 40 is parallel to the first direction L1, and the distance between the first surface of the substrate 40 and the roll coating position remains constant, using a roll coating assembly 1 to roll coat a perovskite liquid film onto the first surface of the substrate 40. Alternatively, for example, the first motor can be controlled to drive the substrate 40 to move along the first direction L1. When the angle between the first surface of the substrate 40 and the first direction L1 is 0.1°, 0.5°, 1°, 2°, 5°, 6°, 8°, 9°, 10°, 10.5°, 13°, 15°, 18°, or 20°, and the distance between the first surface of the substrate 40 and the roller coating position remains constant, the roller coating assembly 1 is used to roll-coat the first surface of the substrate 40 with a perovskite liquid film.

[0094] In some embodiments, refer to Figure 4 The roll coating process may include: controlling a first motor and a second motor to drive the substrate 40 to move along a first direction L1 and a second direction L2, and controlling a third motor to drive the substrate to rotate. When the angle b between the first surface of the substrate 40 and the first direction L1 is greater than a first preset angle, and the distance between the first surface of the substrate 40 and the roll coating position remains constant, the roll coating assembly 1 is used to roll coat the first surface of the substrate 40 with a perovskite liquid film. Here, the first preset angle is equal to 20°. That is to say, when the first surface of the substrate 40 has a large angle with the first direction L1, and the first surface of the substrate 40 is rolled at a certain angle, and the distance between the first surface of the substrate 40 and the roll coating position remains constant, the problem of the thinness of the perovskite liquid film at the beginning of the roll coating of the substrate can be improved, and the thickness of the perovskite film layer can be made more uniform.

[0095] It should be noted that, for Figure 4 In the roll coating process, the first surface of the substrate 40 makes an angle b with the first direction L1, and the substrate moves at a speed V along the first direction L1. X The velocity of the base moving along the second direction L2 is V Z Then, tanb = V Z ÷V X .

[0096] In some embodiments, refer to Figure 5The perovskite thin film roll coating apparatus further includes: a housing 500 located outside the conveying assembly 2, the roll coating assembly 1, and the uniform coating assembly 3, and an atmosphere conditioning assembly located outside the housing 500; the housing 500 is provided with a feed inlet 510, a discharge outlet 520, and a gas inlet; the number of gas inlets can be one or more, for example... Figure 5 The atmosphere conditioning assembly includes gas inlets 531 and 532. A cooler 540 and a conduit 530 passing through the cooler 540 are also included. The conduit 530 is connected to the housing 500 via the gas inlets, and inert gas is introduced into the conduit 530. The cooler 540 can be set to ambient temperature or a lower temperature, such as 0°C, 3°C, 5°C, 8°C, 10°C, 12°C, 15°C, 17°C, 20°C, or 23°C. When the inert gas in the conduit 530 passes through the cooler 540, its temperature drops to the corresponding temperature. The low-temperature inert gas, passing through the conduit 530, is injected into the housing 500 through gas inlets 531 / 532. The continuously blowing low-temperature inert gas not only removes oxygen and water vapor from the housing 500 but also prevents the perovskite solution from being oxidized by oxygen and water vapor. Furthermore, the low-temperature inert gas maintains a low internal temperature within the casing 500, which reduces the evaporation of the perovskite solution, ensuring its concentration, and slows down the crystallization of the perovskite liquid film on the substrate during the roll coating process, thus improving the crystallization quality of the perovskite film. The specific choice of inert gas is not limited; for example, nitrogen can be used because it is readily available and inexpensive. Nitrogen gas can be introduced before roll coating or before the perovskite solution is added to the perovskite solution tank to purge oxygen and moisture from the casing, preventing the perovskite solution from being oxidized by oxygen and moisture.

[0097] The feed port here is used at least to allow the substrate 40 to enter the housing, and the discharge port is used at least to allow the substrate after homogenization to exit the housing.

[0098] In some embodiments, refer to Figure 5 and Figures 9 to 10The conveying assembly 2 includes a drive cone wheel 600, located at least between the uniform coating assembly 3 and the discharge port 520. The drive cone wheel 600 includes a bearing inclined surface 610 near the roller coating position. The drive cone wheel 600 carries the substrate 40 passing through the uniform coating assembly 3 via the bearing inclined surface 610 near the roller coating position. The perovskite liquid film 141 on the substrate 40 is close to the bearing inclined surface 610 adjacent to the roller coating position. Therefore, the substrate with the perovskite liquid film does not need to be flipped, and no flipping structure is required. The structure of the device is simple. At the same time, since no flipping is required, the thickness of the perovskite liquid film is avoided during the flipping process. Also, since it is a bearing inclined surface, it has almost no contact with the perovskite liquid film 141 on the substrate 40, thereby avoiding damage to the perovskite liquid film. The contact area of ​​the other substrates 40 is small, which also avoids damage to the substrate. The substrate is then conveyed outside the housing 500.

[0099] In some embodiments, the drive cone wheel includes a bearing inclined surface near the roller coating position, on which a bearing groove is provided for limiting the end of the substrate 40. The end of the substrate 40, after passing through the uniform coating assembly 3, is placed in the bearing groove. During the transmission process of the drive cone wheel, the substrate 40 is more stable due to the limiting effect of the bearing groove. It should be noted that the size of the bearing groove is not limited; as long as the substrate 40 can be transported smoothly, the size of the bearing groove can be as small as possible.

[0100] The transmission cone 600 here can be Figure 9 The aforementioned pyramidal-shaped transmission cone wheel, or Figure 10 The cone-shaped transmission wheel shown is not limited in its specific shape.

[0101] In some embodiments, the perovskite thin film roll coating apparatus further includes an air knife assembly (not shown), located within the housing 500 and after the uniform coating assembly 3. The air knife assembly is used to blow compressed air onto a first surface of the substrate to rapidly evaporate excess solvent in the perovskite liquid film on the first surface and to promote grain nucleation, thereby obtaining a perovskite thin film. The temperature of the compressed air can be from 20°C to 100°C, and the angle between the blowing direction of the compressed air and the second direction L2 can be less than or equal to 45°. For example, the temperature of the compressed air can be 20°C, 25°C, 30°C, 40°C, 50°C, 60°C, 65°C, 70°C, 80°C, 90°C, or 100°C. The direction of compressed air purging can be parallel to the second direction L2, or the angle between the two can be 0.5°, 1°, 5°, 8°, 10°, 12°, 15°, 18°, 20°, 25°, 30°, 32°, 35°, 40°, or 45°.

[0102] In some embodiments, a perovskite liquid film is roll-coated onto the first surface of the substrate 40 during the uniform motion of the substrate 40 along the first direction L1. Specifically, since this application specifically provides a film-leveling component located after roll coating to reduce the thickness of the perovskite liquid film at the end of the roll coating, the problem of excessive thickness of the perovskite liquid film at the end of the roll coating does not need to be considered during the roll coating process. Therefore, the substrate 40 moves at a uniform speed along the first direction L1, and the speed control of the substrate is simple and easy to implement.

[0103] In some embodiments, the roll coating assembly 1 includes a roll coating roller; before roll coating, it may further include: when the first surface of the substrate 40 is opposite to the roll coating roller, the substrate 40 is controlled to remain stationary for a preset time by the conveying assembly 1, and during the preset time, the roll coating roller continues to rotate, so the perovskite solution between the substrate 40 and the roll coating roller will gradually accumulate and increase. When the accumulation of the perovskite solution reaches a stable level, the accumulation of the perovskite solution will no longer increase, and then the roll coating of the perovskite liquid film begins. Since the solution accumulation process during the roll coating process is avoided, the thin film thickness at the beginning of the roll coating of the substrate will be effectively improved, which is conducive to forming a uniform perovskite film layer at the beginning and middle of the roll coating of the substrate.

[0104] The preset duration here is from 1 second to 120 seconds. Specifically, the duration for which the cumulative amount of perovskite solution between the substrate 40 and the roller coating roller continuously increases is usually within 120 seconds. If the preset duration is greater than 120 seconds, the cumulative amount of perovskite solution between the substrate 40 and the roller coating roller no longer increases and reaches a balance. Therefore, a preset duration greater than 120 seconds leads to wasted time. If the preset duration is less than 1 second, the cumulative amount of perovskite solution between the substrate 40 and the roller coating roller is small and cannot significantly improve the problem of thin film thickness at the beginning of roller coating of the substrate. Therefore, a preset duration of 1 second to 120 seconds will not lead to wasted time and can significantly improve the problem of thin film thickness at the beginning of roller coating of the substrate.

[0105] For example, the preset duration can be 1 second, 2 seconds, 2.5 seconds, 3 seconds, 4 seconds, 5 seconds, 6 seconds, 7 seconds, 8 seconds, 9 seconds, 7.5 seconds, 10 seconds, 20 seconds, 30 seconds, 50 seconds, 60 seconds, 80 seconds, 100 seconds, 110 seconds, or 120 seconds.

[0106] Furthermore, controlling the substrate to remain stationary here may include: when the distance between the first surface of the substrate 40 and the coating roller is less than a first distance, controlling the substrate to remain stationary for a first preset duration; the first preset duration is from 1 second to 60 seconds; when the distance between the first surface of the substrate 40 and the coating roller is greater than the first distance, controlling the substrate to remain stationary for a second preset duration; the second preset duration is from 1 second to 60 seconds; during the first and second preset durations, the coating roller continues to rotate, and the aforementioned coating step includes: when the distance between the first surface of the substrate 40 and the uniform coating roller is equal to the first distance, using the coating roller to coat the first surface of the substrate 40 with a perovskite liquid film. Specifically, firstly, with a small gap between the first surface of the substrate 40 and the coating roller, the substrate is kept stationary. Due to the small gap, a certain amount of perovskite liquid film can be quickly adhered to almost the entire first surface of the substrate 40. Then, with a larger gap between the first surface of the substrate 40 and the coating roller, the substrate is kept stationary. Under the tension of the perovskite liquid film adhered to almost the entire first surface of the substrate 40, the perovskite solution between the first surface of the substrate 40 and the coating roller accumulates quickly and reaches a stable state before the coating process begins. This can reliably improve the problem of thin film thickness at the beginning of the coating process.

[0107] For example, the duration of the first sub-preset here can be 1 second, 1.5 seconds, 2 seconds, 2.5 seconds, 3 seconds, 4 seconds, 5 seconds, 8 seconds, 10 seconds, 12 seconds, 15 seconds, 18 seconds, 20 seconds, 25 seconds, 30 seconds, 35 seconds, 40 seconds, 42 seconds, 45 seconds, 50 seconds, 55 seconds, or 60 seconds. Similarly, the duration of the second sub-preset here can be 1 second, 1.5 seconds, 2 seconds, 2.5 seconds, 3 seconds, 4 seconds, 5 seconds, 7 seconds, 9 seconds, 10 seconds, 15 seconds, 17 seconds, 20 seconds, 25 seconds, 30 seconds, 35 seconds, 40 seconds, 45 seconds, 50 seconds, 55 seconds, or 60 seconds. There is no requirement that the durations of the first and second sub-presets be equal, nor is there any requirement that their relative lengths be equal.

[0108] Here, the distance between the first surface of the substrate 40 and the roller coating roller can refer to the distance between the lowest point of the first surface of the substrate 40 and the highest point of the roller coating roller along the second direction L2. This first distance refers to the target distance between the first surface of the substrate 40 and the roller coating roller during the roller coating process, which needs to be determined based on the required height of the perovskite film, etc., and its specific size is not limited. For example, the first distance here can be 100 μm. When the distance between the first surface of the substrate 40 and the roller coating roller is less than the first distance, the distance between the first surface of the substrate 40 and the roller coating roller can be 10 μm. When the distance between the first surface of the substrate 40 and the roller coating roller is greater than the first distance, the distance between the first surface of the substrate 40 and the roller coating roller can be 120 μm to 150 μm. Or, when the distance between the first surface of the substrate 40 and the roller coating roller is less than the first distance, the distance between the first surface of the substrate 40 and the roller coating roller can be about one-tenth of the first distance. When the distance between the first surface of the substrate 40 and the roller coating roller is greater than the first distance, the distance between the first surface of the substrate 40 and the roller coating roller can be 1.2 to 1.5 times the first distance.

[0109] It should be noted that during the roll coating process, the substrate's moving speed is V. 基底 The rotational speed of the roller coating roller is V. 辊 Under normal circumstances, V 辊 ÷V 基底 A ratio between 1 and 2 is optimal for the two components. During the roll coating process, the perovskite solution in the perovskite solution tank 110 continuously decreases. To ensure the quality of the roll coating, it is necessary to continuously replenish the perovskite solution tank 110. Q is the volume of perovskite solution replenished to the perovskite solution tank 110 per unit time, and the unit of Q can be milliliters per minute. W is the width of the first surface of the substrate 40. Figures 1 to 5 In the figure, W represents the dimension of the first surface of substrate 40 perpendicular to the paper surface. G represents the aforementioned first distance, i.e., the target distance between the first surface of substrate 40 and the coating roller during the roll coating process. 液膜 Let V be the target thickness of the formed perovskite liquid film. 基底 V 辊 Q, W, h 液膜 When the following formula 1 is satisfied, the thickness of the formed perovskite liquid film is relatively uniform.

[0110]

[0111] In Formula 1, k is a coefficient, and the value of k ranges from 0.5 to 1.

[0112] This application also provides a roll coating method for perovskite thin films, which may include the following steps.

[0113] Step 101: Fix and transfer the base.

[0114] Step 102: Roll-coating a perovskite liquid film onto the first surface of the substrate; the substrate includes a roll-coating start end and a roll-coating end end.

[0115] Step 103: Use a first scraper to scrape down the thickness of the perovskite liquid film located at the end of the roll coating.

[0116] This application describes a roll coating method that achieves the coating of a perovskite liquid film onto the first surface of a substrate. Roll coating is simple to implement and has a high speed, facilitating large-area mass production of perovskite thin films. Simultaneously, the roll coating equipment is relatively simple, effectively reducing equipment investment costs and subsequent raw material usage costs. Addressing the common problem in roll coating where the thickness of the perovskite liquid film at the end of the roll coating is greater than that at other locations, or a trailing phenomenon, this application employs a first scraper after roll coating to reduce the thickness of the perovskite liquid film at the end of the roll coating. This ensures that the thickness of the perovskite liquid film at various locations on the first surface of the substrate is approximately equal, thereby improving the performance of the formed perovskite solar cell.

[0117] In some embodiments, the process between steps 102 and 103 may further include: rotating the substrate 40 such that, in the second direction, the end of the roll coating on the substrate is closer to the first scraper than the beginning of the roll coating on the substrate, and the angle α between the first surface of the substrate and the first direction is 0.1° to 20°; the first direction is different from the second direction, and the relative positional relationship between the first direction and the second direction can be referred to the foregoing description, and will not be repeated here to avoid repetition. The aforementioned step 103 may include: during the movement of the substrate along the first direction, the thickness of the perovskite liquid film located at the end of the roll coating is reduced by the first scraper. The first scraper of the film homogenizing assembly 3 reduces the excess thickness of the perovskite liquid film located at the end of the roll coating. That is to say, during the film homogenizing process, the substrate 40 no longer moves along the second direction L2 towards the direction of the first scraper. Therefore, the part of the substrate 40 outside the end of the roll coating will not contact the first scraper. Only the thicker perovskite liquid film 141 at the end of the roll coating in the substrate 40 will contact the first scraper and have some thickness removed. That is to say, during the film homogenizing process, the perovskite liquid film 141 outside the end of the roll coating in the substrate 40 will not be affected, avoiding material waste. Only the excess perovskite liquid film 141 at the end of the roll coating in the substrate 40 is cleaned. After cleaning the excess perovskite liquid film 141 at the end of the roll coating in the substrate 40, a complete perovskite liquid film with uniform thickness will be formed on the first surface of the substrate 40. Moreover, the process of homogenizing the film only requires controlling the first motor 23, which is simple and easy to implement.

[0118] It should be noted that the included angle α here is between 0.1° and 20°, which not only does not affect the thickness of the perovskite liquid film 141 outside the end of the roll coating in the substrate 40, but also can cleanly remove the excess perovskite liquid film 141 at the end of the roll coating in the substrate 40.

[0119] In some embodiments, step 102 may include at least one of steps 1021 to 1023 described below.

[0120] Step 1021: While the substrate moves along the first direction, and the angle between the first surface of the substrate and the first direction is less than or equal to a first preset angle, and the distance between the first surface of the substrate and the roller coating position remains constant, a perovskite liquid film is roller coated on the first surface of the substrate; that is, roller coating is performed when the first surface of the substrate 40 is approximately parallel to the first direction L1, and the roller coating control process is simple.

[0121] Step 1022: When the substrate moves along the first direction and the second direction, and the angle between the first surface of the substrate and the first direction is greater than a first preset angle, and the distance between the first surface of the substrate and the roller coating position remains constant, a perovskite liquid film is roller coated on the first surface of the substrate. That is, when the first surface of the substrate 40 has a large angle with the first direction L1, and the first surface of the substrate 40 is roller coated at a certain angle while the distance between the first surface of the substrate 40 and the roller coating position remains constant, the problem of the perovskite liquid film being too thin at the beginning of the roller coating can be improved, ensuring a more uniform film thickness for the perovskite film layer.

[0122] Step 1023: With the substrate moving along a first direction, the angle between the first surface of the substrate and the first direction being less than or equal to a first preset angle, the distance between the first surface of the substrate and the coating position remaining constant, and both the start and end ends of the coating process located on the diagonal of the first surface, a perovskite liquid film is coated onto the first surface of the substrate; wherein the first preset angle is equal to 20°. In this case, during the coating process, both the start and end ends of the coating process are vertices of the substrate 40, reducing the non-uniform portion of the perovskite liquid film to the vertices, resulting in a smaller area of ​​non-uniformity and better uniformity of the perovskite thin film thickness obtained by the coating process, further improving the performance of the perovskite solar cell. The first preset angle of 20° means that the first surface of the substrate 40 is approximately parallel to the first direction L1 of the substrate 40's movement. Maintaining a constant distance between the first surface of the substrate 40 and the coating position can mean that the distance between the first surface of the substrate 40 and the coating position remains constant along the second direction L2.

[0123] In some embodiments, step 102 may include performing multiple roll coatings on the first surface of the substrate, thereby reducing the problem of incomplete roll coating or short-circuit points and ensuring the roll coating quality of the perovskite film. Here, "multiple times" can be 2, 3, 4, etc.

[0124] In some embodiments, during the roll coating process, the distance between the first surface of the substrate and the roll coating position is 1 μm to 200 μm. Specifically, during the roll coating process, along the second direction L2, the distance between the first surface of the substrate and the roll coating position is 1 μm to 200 μm. The definition of the roll coating position is as described above and will not be repeated here. If the distance between the first surface of the substrate and the roll coating position is less than 1 μm during the roll coating process, the resulting perovskite film is too thin. If the distance is greater than 200 μm, the perovskite solution does not contact the first surface sufficiently, resulting in discontinuities in the perovskite film and insufficient continuity. Therefore, in this application, the distance between the first surface of the substrate and the roll coating position is 1 μm to 200 μm during the roll coating process, which ensures that the perovskite film obtained by roll coating has a suitable thickness and virtually no discontinuities, resulting in good continuity. For example, in the roll coating process: the distance between the first surface of the substrate and the roll coating position can be 1μm, 2μm, 10μm, 30μm, 50μm, 60μm, 80μm, 100μm, 120μm, 150μm, 160μm, 180μm, or 200μm.

[0125] In some embodiments, during the roll coating process, the substrate's movement speed is from 10 mm / s to 150 mm / s, specifically, along the first direction L1. If the substrate's movement speed is greater than 150 mm / s, the resulting perovskite film will not be uniform in thickness; if the speed is less than 10 mm / s, production efficiency will be low. Therefore, in this application, the substrate's movement speed during the roll coating process is from 10 mm / s to 150 mm / s, which not only ensures uniform perovskite film thickness but also achieves higher production efficiency.

[0126] For example, during the roll coating process: the substrate movement speed is 10mm / s, 20mm / s, 30mm / s, 35mm / s, 40mm / s, 50mm / s, 60mm / s, 70mm / s, 75mm / s, 80mm / s, 90mm / s, 100mm / s, 110mm / s, 120mm / s, 130mm / s, and 150mm / s.

[0127] In some embodiments, the aforementioned step 102 may include: during the uniform motion of the substrate along the first direction, a perovskite liquid film is rolled onto the first surface of the substrate. Since this application specifically provides an operation to scrape down the perovskite liquid film at the end of the roll coating after the roll coating, it is not necessary to consider the problem of the perovskite liquid film being too thick at the end of the roll coating during the roll coating process. The substrate 40 moves at a uniform speed along the first direction L1, and the speed control of the substrate is simple and easy to implement.

[0128] In some embodiments, the perovskite thin film roll coating method provided in this application can be applied to any of the aforementioned perovskite thin film roll coating apparatuses. For details regarding the applicability of this perovskite thin film roll coating method to any of the aforementioned perovskite thin film roll coating apparatuses, please refer to the relevant descriptions in the aforementioned perovskite thin film roll coating apparatuses; to avoid repetition, they will not be repeated here.

[0129] It should be noted that the perovskite thin film roll coating method provided in this application can be used interchangeably with any of the aforementioned perovskite thin film roll coating apparatuses. To avoid repetition, the relevant details will not be repeated.

[0130] The present application will be further explained below with reference to specific embodiments.

[0131] Example 1

[0132] Combination Figure 1 , Figure 2 and Figure 5 The first motor 23 of the conveying component drives the adsorption mechanism 22 to move along the first direction L1 to the feeding port 510. Then the second motor 24 drives the adsorption mechanism 22 to descend along the second direction L2, moving the adsorption mechanism 22 above the substrate 40. After the adsorption mechanism 22 adsorbs the substrate 40, the second motor 24 first drives the adsorption mechanism 22 to rise and leave the feeding position. The first motor 23 moves the adsorption mechanism 22 horizontally along the first direction L1 to above the No. 1 roller coating roller 120. Then the second motor 24 lowers the height of the adsorption mechanism 22 so that the position on the first surface of the substrate 40 corresponding to the roller coating start end falls above the No. 1 roller coating roller 120, and the distance between the substrate 40 and the No. 1 roller coating roller 120 is the first distance. The substrate 40 remains stationary at this position for approximately 2 seconds. During this period, the No. 1 coating roller 120 rotates continuously, turning clockwise. The perovskite solution between the substrate 40 and the No. 1 coating roller 120 gradually accumulates. Once the accumulation of the perovskite solution reaches a stable level, it will no longer increase. After this, the first motor 23 drives the substrate 40 to move horizontally along the first direction L1, initiating the roller coating process. A uniform perovskite film layer is formed at the starting and middle positions of the substrate.

[0133] Next, the first motor 23 moves the substrate 40 horizontally forward along the first direction L1 to the position of the uniform coating roller 320, and the apex of the uniform coating roller 320 is slightly lower than the apex of the first coating roller 120. The third motor rotates the substrate counterclockwise by an angle α, such as 1°. Then the first motor 23 continues to drive the substrate 40 to move horizontally forward along the first direction L1. When passing the uniform coating roller 320, the position of the substrate other than the end of the roll coating will basically not come into contact with the uniform coating roller 320. Only the excessively thick perovskite liquid film at the end of the roll coating of the substrate comes into contact with the uniform coating roller 320 and is partially removed by the uniform coating roller 320. After cleaning the excess perovskite liquid film at the end of the roll coating, a complete perovskite film layer with uniform thickness will be formed on the surface of the substrate. The perovskite solution film on the surface of the uniform film roller 320 enters the solvent tank 310 as the uniform film roller 320 rotates, and is dissolved by the perovskite solvent in the solvent tank 310. The perovskite solvent remaining on the surface of the uniform film roller 320 is scraped off by the second scraper 330. The uniform film roller 320 is driven by a motor to rotate counterclockwise.

[0134] After the excess perovskite liquid film at the end of the roll coating of the substrate is cleaned up, the conveying assembly will convey the substrate to the discharge port 520.

[0135] Example 2

[0136] The only difference between Example 2 and Example 1 is the number of roller coating components; all other aspects are the same. The following explanation focuses on these differences. (Refer to...) Figure 3 Two roller coating assemblies sequentially perform two roller coatings on the first surface of the substrate.

[0137] Example 3

[0138] The only difference between Example 3 and Example 1 is the included angle of the first surface of the substrate during the roll coating process; all other aspects are the same. The following explanation focuses on these differences. (Refer to...) Figure 4 The third motor then participates, driving the substrate to rotate so that the angle b between the first surface of the substrate and the first direction L1 is 45°. The second motor 24 and the first motor 23 control the substrate 40 to move at the same speed along the second direction L2 and along the first direction L1, thus performing roll coating.

[0139] Example 4

[0140] The only difference between Example 4 and Example 1 is the coating direction of the first surface of the substrate during the roll coating process; all other aspects are the same. The following explanation focuses on the differences. A fourth motor is involved, ensuring that both the start and end points of the roll coating are located diagonally opposite the first surface, thus enabling the roll coating of a perovskite liquid film onto the first surface of the substrate.

[0141] Example 5

[0142] The only difference between Example 5 and Example 1 is the way the substrate is stationary before the start of roller coating; the rest is the same. The following explanation focuses on the differences. Here, the first distance can be 100 μm. If the distance between the first surface of substrate 40 and the roller coating roller is 10 μm, the substrate remains stationary for 2 seconds. Then, if the distance between the first surface of substrate 40 and the roller coating roller is 120 μm, the substrate remains stationary for 4 seconds. During the 6 seconds the substrate remains stationary, the roller coating roller continues to rotate, and then roller coating begins.

[0143] It should be noted that, for the sake of simplicity, the method embodiments are all described as a series of actions. However, those skilled in the art should understand that the embodiments of this application are not limited to the described order of actions, because according to the embodiments of this application, some steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also understand that the embodiments described in the specification are all preferred embodiments, and the actions involved are not necessarily essential to the embodiments of this application.

[0144] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0145] The terms "an embodiment," "embodiment," or "one or more embodiments" as used herein mean that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment of this application. Furthermore, please note that the examples of the phrase "in one embodiment" do not necessarily all refer to the same embodiment.

[0146] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A roll coating device of a perovskite thin film, characterized by, The device comprises: a roller coating assembly, a conveying assembly and a film leveling assembly; the conveying assembly is used to fix and convey the substrate; the roller coating assembly is used to roll coat perovskite liquid film on the first surface of the substrate; the substrate has a roller coating start end and a roller coating end; the film leveling assembly comprises a solvent tank and a first scraper; the solvent tank contains perovskite solvent; the first scraper is used to scrape the perovskite liquid film at the roller coating end to a lower thickness; at least part of the first scraper is immersed in the perovskite solvent in the solvent tank, and the perovskite solvent is used to dissolve the perovskite liquid film remaining on the first scraper.

2. The roll coating apparatus of the perovskite thin film according to claim 1, characterized by, The conveying assembly comprises a guide rail, a first motor, a second motor and a third motor arranged on the guide rail, and a suction mechanism connected to the first motor, the second motor and the third motor; the suction mechanism is used to adsorb and fix the substrate; the first motor is used to drive the suction mechanism to move in a first direction; the second motor is used to drive the suction mechanism to move in a second direction; the third motor is used to rotate the suction mechanism; the first direction is different from the second direction; In the second direction, the scraping position of the first scraper is farther away from the suction mechanism than the roller coating position of the roller coating assembly.

3. The roll coating apparatus of the perovskite thin film according to claim 1, characterized by, The film leveling assembly further comprises a second scraper used to control the amount of perovskite solvent remaining on the first scraper; the second scraper is located between the scraping position of the first scraper and the solvent tank; The projection of the contact position of the first scraper and the second scraper in the direction of gravity is located in the solvent tank.

4. The roll coating apparatus for perovskite thin film according to claim 3, wherein The first scraper comprises one of a film leveling roller, a scraper, a doctor blade and a cloth; The second scraper comprises one of a scraper, a doctor blade and a cloth; The material of the second scraper is selected from at least one of plastic and rubber.

5. The roll coating apparatus of the perovskite thin film according to claim 1, characterized by, The roller coating assembly comprises a perovskite solution tank, a third scraper and a roller coating roller; the perovskite solution tank contains perovskite solution; the third scraper and the roller coating roller are arranged at intervals; In the rotation direction of the roller coating roller, the third scraper is located between the perovskite solution tank and the roller coating position.

6. The roll coating apparatus of the perovskite thin film according to claim 5, characterized by The projection of the position of the third scraper close to the roller coating roller in the direction of gravity is located in the perovskite solution tank.

7. The perovskite film roller coating device according to claim 5, wherein The third scraper comprises one of a scraper, a doctor blade and a cloth; The material of the third scraper is selected from at least one of plastic and rubber.

8. The roll coating apparatus of the perovskite thin film according to claim 1, wherein The number of roller coating assemblies is greater than or equal to 2, and each roller coating assembly is arranged in sequence along the movement direction of the substrate during the roller coating process.

9. The roll coating apparatus of the perovskite thin film according to claim 2, characterized by, The suction mechanism comprises a suction surface, and the conveying assembly further comprises a fourth motor arranged on the guide rail, the suction mechanism and the fourth motor are connected, and the fourth motor is used to drive the suction surface of the suction mechanism to rotate.

10. The roll coating apparatus for perovskite thin film according to any one of claims 1 to 9, characterized by Further comprising an outer shell located outside the conveying assembly, the roller coating assembly and the film leveling assembly, and an atmosphere adjusting assembly located outside the outer shell; the outer shell is provided with a feeding port, a discharging port and a gas inlet; The atmosphere conditioning assembly includes: a cooler, and a pipe passing through the cooler, the pipe being connected to the housing via the gas inlet; an inert gas is introduced into the pipe.

11. The roll coating apparatus for perovskite thin films according to claim 10, characterized in that, The conveying assembly includes: a drive cone wheel, located at least between the uniform coating assembly and the discharge port; the drive cone wheel includes: a bearing ramp near the roller coating position, the drive cone wheel carrying the substrate passing through the uniform coating assembly via the bearing ramp, the perovskite liquid film on the substrate being close to the bearing ramp, and conveying the substrate outside the housing; and / or, The perovskite thin film roll coating apparatus further includes an air knife assembly located after the film uniform assembly inside the housing, the air knife assembly being used to blow compressed air onto a first surface of the substrate.

12. A method of roll coating a perovskite thin film, characterized by, include: Fix and transfer the base; A perovskite liquid film is roll-coated onto the first surface of the substrate; the substrate includes: a roll-coating start end and a roll-coating end end; The thickness of the perovskite liquid film located at the end of the roll coating is reduced by using a first scraper.

13. The roll coating method of a perovskite thin film according to claim 12, characterized by, After roller coating, the previously described method also includes: The substrate is rotated such that, in the second direction, the end of the roll coating on the substrate is closer to the first scraper than the beginning of the roll coating on the substrate, and the angle between the first surface of the substrate and the first direction is 0.1° to 20°; the first direction is different from the second direction. The scraping step includes: During the movement of the substrate along the first direction, the thickness of the perovskite liquid film located at the end of the roll coating is reduced using the first scraper.

14. The roll coating method of a perovskite thin film according to claim 12, characterized by, The roller coating step includes at least one of the following steps: When the substrate moves along a first direction, and the angle between the first surface of the substrate and the first direction is less than or equal to a first preset angle, and the distance between the first surface of the substrate and the roller coating position remains constant, a perovskite liquid film is roller coated on the first surface of the substrate. When the substrate moves along a first direction and a second direction, and the angle between the first surface of the substrate and the first direction is greater than a first preset angle, and the distance between the first surface of the substrate and the roller coating position remains constant, a perovskite liquid film is roller coated on the first surface of the substrate. When the substrate moves along a first direction, the angle between the first surface of the substrate and the first direction is less than or equal to a first preset angle, the distance between the first surface of the substrate and the roller coating position remains constant, and the roller coating start end and roller coating end end are both located on the diagonal of the first surface, a perovskite liquid film is roller coated on the first surface of the substrate. Wherein, the first preset angle is equal to 20°.

15. The roll coating method for perovskite thin films according to claim 12, characterized in that, The roll coating step includes: performing multiple roll coatings on the first surface of the substrate; and / or... During the roll coating process: the distance between the first surface of the substrate and the roll coating position is 1 μm to 200 μm, and / or, during the roll coating process: the movement speed of the substrate is 10 mm / s to 150 mm / s; and / or, the roll coating step includes: during the uniform movement of the substrate along a first direction, roll coating a perovskite liquid film onto the first surface of the substrate.

16. The roll coating method of a perovskite thin film according to any one of claims 12 to 15, characterized by, The uniform film assembly includes: a first scraper; after the scraping step, the method further includes: The first scraper is immersed in the perovskite solvent, and the perovskite solvent dissolves the perovskite liquid film remaining on the first scraper; Control the amount of perovskite solvent remaining on the first scraper.

17. The roll coating method of a perovskite thin film according to any one of claims 12 to 15, characterized by, The film-spinning assembly includes: a film-spinning roller; the scraping step includes: The rotation direction of the scraping roller is controlled to be opposite to the movement direction of the substrate, so as to scrape down the thickness of the perovskite liquid film located at the end of the roll coating; and / or, The roll coating assembly includes a roll coating roller. Before roll coating, the method further includes: controlling the substrate to remain stationary for a preset time while the first surface of the substrate is opposite to the uniform film roller, and during the preset time, the roll coating roller continuously rotates to accumulate perovskite solution between the substrate and the roll coating roller; the preset time is from 1 second to 120 seconds.

18. The roll coating method of a perovskite thin film according to claim 17, characterized by, The control of the substrate remaining stationary for a preset duration includes: When the distance between the first surface of the substrate and the roller coating roller is less than a first distance, the substrate is controlled to remain stationary for a first preset duration; the first preset duration is from 1 second to 60 seconds. When the distance between the first surface of the substrate and the roller coating roller is greater than the first distance, the substrate is controlled to remain stationary for a second preset duration; the second preset duration is from 1 second to 60 seconds. The roller coating step includes: When the distance between the first surface of the substrate and the coating roller is equal to the first distance, the perovskite liquid film is coated onto the first surface of the substrate using the uniform coating roller.

Images