Coating Equipment

Abstract

To provide a coating device capable of applying a coating liquid to a coating surface of a substrate after performing a sufficient surface treatment on the coating surface, and preventing problems such as roughening of the coating surface from occurring. [Solution] A coating device (10) of an embodiment includes a surface treatment section (12) that performs surface treatment on a coating surface, which is one side of a substrate (1), and a coating section (13) that applies a coating liquid to the surface after the surface treatment. The coating liquid is a coating liquid that will become one of the layers that make up a perovskite solar cell. The surface treatment section (12) includes rollers (41-45) that transport the substrate (1) and an excimer lamp (40) that emits excimer light toward the coated surface of the substrate (1) being transported. A predetermined distance is maintained between the coated surface of the substrate (1) being transported by the rollers (41-45) and the light-emitting surface of the excimer lamp (40). The surface treatment section (12) applies excimer light to the substrate with an integrated light amount of 1000 mJ / cm. 2 More than 10000mJ / cm 2 The present invention is characterized in that the excimer light is irradiated as follows:

Description

[Technical Field]

[0001] The present invention relates to a coating device. [Background technology]

[0002] In recent years, perovskite solar cells have attracted attention as a promising thin, lightweight, and highly efficient solar cell. Perovskite solar cells generate electricity by absorbing sunlight in the perovskite layer and generating free electrons and holes.

[0003] Known perovskite solar cell structures include mesoporous, forward, and reverse structures. Each structure consists of multiple layers stacked together. For example, a forward structure consists of a transparent electrode, an electron transport layer, a perovskite layer, a hole transport layer, and a back electrode stacked in this order.

[0004] In these structures, each layer is formed by applying a liquid coating solution onto the surface of a substrate. For example, when a perovskite layer is to be formed during the process of manufacturing a normal-structure perovskite solar cell, a coating solution containing a perovskite precursor is applied to the surface (electron-transport-layer-side surface) of a substrate having a structure in which a transparent electrode and an electron-transport layer are laminated on a film or glass substrate.

[0005] In order for the applied coating liquid to form a uniform layer without unevenness on the substrate, it is necessary for the surface of the substrate to be coated (the surface of the substrate to which the coating liquid is applied) to have sufficient wettability before the coating liquid is applied. Therefore, before the coating liquid is applied, the surface to be coated is subjected to a surface treatment to improve wettability. Known examples of such surface treatments include corona treatment and plasma treatment, as described in Patent Document 1, as well as chemical treatment and UV treatment using a low-pressure mercury lamp. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2023-181939 Summary of the Invention [Problem to be solved by the invention]

[0007] However, corona treatment and plasma treatment have problems such as roughening or alteration of the substrate surface. Furthermore, chemical treatment has problems such as the chemical solution penetrating into the substrate, changing the substrate's properties, and the need for a process of washing and drying the substrate after chemical treatment. Furthermore, low-pressure mercury lamps have a low output, so in order to achieve a sufficient surface treatment effect using a low-pressure mercury lamp, it is necessary to irradiate the substrate with ultraviolet light from the low-pressure mercury lamp for a long period of time. For example, even if a long substrate being transported in one direction is irradiated with ultraviolet light from a low-pressure mercury lamp at a fixed location, each portion of the substrate is only irradiated with ultraviolet light for a short period of time, resulting in insufficient surface treatment of the substrate.

[0008] The present invention has been made in consideration of these circumstances, and aims to provide a coating device that can apply a coating liquid after performing sufficient surface treatment on the coating surface of a substrate, while at the same time preventing problems such as roughening of the coating surface during surface treatment. [Means for solving the problem]

[0009] The coating device of the embodiment includes an unwinding unit that unwinds a substrate, a surface treatment unit that performs surface treatment on one of the surfaces of the unwound substrate to be coated, a coating unit that applies a coating liquid to the surface of the substrate after the surface treatment, and a winding unit that winds up the substrate to which the coating liquid has been applied. In the perovskite layer or mesoporous titanium oxide layer The coating liquid is the coated surface of the substrate is a surface of a layer that will come into contact with a layer of the coating liquid in the perovskite solar cell having a layered structure,The surface treatment section includes a roller for transporting the substrate and an excimer lamp for irradiating excimer light onto the coated surface of the substrate being transported, and a predetermined distance is maintained between the coated surface of the substrate being transported by the roller and a light emitting surface of the excimer lamp, and the surface treatment section irradiates the substrate with an integrated light amount of 1000 mJ / cm. 2 More than 10000mJ / cm 2 The present invention is characterized in that the excimer light is irradiated as follows: [Effects of the Invention]

[0010] The coating device of the embodiment can achieve the effect of surface treatment by irradiating the substrate for a short period of time, and uses excimer light that is less likely to roughen the irradiated surface.Therefore, the coating surface of the substrate can be sufficiently surface-treated before the coating liquid is applied, and problems such as roughening of the coating surface are less likely to occur during surface treatment. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. [Figure 2] FIG. [Figure 3] FIG. [Figure 4] Cross-sections of perovskite solar cells. (a) Mesoporous structure, (b) Normal structure, (c) Inverted structure. DETAILED DESCRIPTION OF THE INVENTION

[0012] A coating apparatus 10 according to one embodiment of the present invention will now be described. The coating apparatus 10 of this embodiment is an apparatus that applies a coating liquid to a substrate in order to form a perovskite layer, which is one of the multiple layers that make up a perovskite solar cell.

[0013] (1) Overall Configuration of Coating Device 10 A simplified view of a coating apparatus 10 is shown in Figure 1. The coating apparatus 10 includes an unwinding section 11, a surface treatment section 12, a coating section 13, a solvent removal section 14, a crystallization section 15, and a winding section 16. The surface treatment section 12, the coating section 13, the solvent removal section 14, the crystallization section 15, and the winding section 16 are each enclosed by walls. However, each wall enclosing these sections has an opening formed therein through which the substrate 1 can pass.

[0014] A first pressure adjustment chamber 17 is provided between the coating section 13 and the solvent removal section 14, a second pressure adjustment chamber 18 is provided between the solvent removal section 14 and the crystallization section 15, and a third pressure adjustment chamber 19 is provided between the crystallization section 15 and the winding section 16. Each of the pressure adjustment chambers 17, 18, 19 is separated from the adjacent sections on both sides by partition walls having openings through which the substrate 1 can pass.

[0015] In this embodiment, the long substrate 1 before the coating liquid is applied has a transparent electrode and an electron transport layer laminated on a flexible film made of a transparent resin such as a polyethylene terephthalate film.

[0016] The unwinding section 11 is provided with a winding shaft 20. The substrate 1 before coating with the coating liquid is wound in a roll around the winding shaft 20. The winding shaft 20 is rotated by the drive of a motor to unwind the substrate 1. The width of the substrate 1 (the length in the direction perpendicular to the conveyance direction and the thickness direction) is, for example, 200 mm to 1000 mm.

[0017] The surface treatment section 12 is a section that performs surface treatment on the substrate 1 transported from the unwinding section 11. The surface treatment is a treatment that improves the wettability of the electron transport layer of the substrate 1. The surface treatment section 12 will be described in detail later.

[0018] The coating section 13 is provided with a die 21 and a backup roller 22 facing the die 21. The die 21 ejects the coating liquid toward the substrate 1 in contact with the backup roller 22, and applies the coating liquid to the entire width of the substrate 1. The surface of the substrate 1 to which the coating liquid is applied is referred to as the coated surface.

[0019] In this embodiment, the coating liquid contains a perovskite precursor and a solvent. The perovskite precursor is a material in a stage before it crystallizes to form perovskite. For example, when attempting to produce methylammonium lead iodide (CH3NH3PbI3) as the perovskite, lead iodide (PbI2) and methylammonium iodide (CH3NH3I) are used as the perovskite precursors.

[0020] The solvent absorbs infrared light at a wavelength different from that of the perovskite precursor. In this embodiment, the solvent is a mixture of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO). DMSO is used to grow perovskite crystals, but its high surface tension makes it difficult to wet the substrate 1. Therefore, it is necessary to adjust the ratio of DMF to DMSO. In this embodiment, the preferred ratio of DMF to DMSO in the solvent is DMF:DMSO = 1:1 to 6:1 by volume.

[0021] In the solvent removal section 14, a plurality of transport rollers 23 are arranged in the transport direction of the substrate 1. Each transport roller 23 is rotated by driving a motor. The substrate 1 is transported over these transport rollers 23 with the coating liquid layer facing up.

[0022] A single infrared irradiator 24 is provided above the conveying rollers 23 in the solvent removal section 14. The infrared irradiator 24 irradiates infrared light of a wavelength that is absorbed by the solvent in the coating liquid but is not easily absorbed by the perovskite precursor. The infrared irradiator 24 is large enough to irradiate the entire width of the substrate 1 with infrared light.

[0023] Infrared rays from such an infrared irradiation device 24 are irradiated onto the substrate 1 as shown by the dashed arrow in Fig. 1, evaporating the solvent in the coating liquid by radiation. By irradiating the infrared rays, the temperature of the coating liquid becomes higher than the ambient temperature of the solvent removal section 14 (for example, to around 70°C), but does not rise to the temperature at which the perovskite precursor crystallizes and forms a coating film (for example, around 100°C). The ambient temperature in the solvent removal section 14 is a temperature, for example, 30°C to 80°C, that is sufficiently lower than the temperature at which the perovskite precursor crystallizes to form a perovskite layer.

[0024] In the crystallization section 15, a plurality of transport rollers 25 are arranged in the transport direction of the substrate 1. Each transport roller 25 is rotated by driving a motor. The substrate 1 is transported over these transport rollers 25 with the coating liquid layer facing up.

[0025] In the crystallization section 15, a plurality of nozzles 26 are arranged above the transport rollers 25 in the transport direction of the substrate 1. These nozzles 26 blow hot air toward the substrate 1 transported by the transport rollers 25. Also, above the transport rollers 25, suction ports 27 are provided to suck in the hot air inside the crystallization section 15. The suction ports 27 and the nozzles 26 are arranged alternately.

[0026] Air taken in from outside the coating device 10 is heated by a heater (not shown) and blown downward from the nozzle 26 as hot air. The hot air rises in a relatively short time, is sucked into the suction port 27, and is then discharged outside the coating device 10. This air circulation maintains the entire crystallization section 15 at a substantially uniform temperature. The ambient temperature in the crystallization section 15 is the temperature at which the perovskite precursor crystallizes, and is, for example, around 100°C.

[0027] The winding section 16 is a location where the perovskite laminate 2, in which a perovskite layer is formed on the substrate 1, is wound up. A winding shaft 28 is disposed in the winding section 16. The winding shaft 28 is rotated by a motor and winds up the perovskite laminate 2 into a roll. The ambient temperature of the winding section 16 is maintained lower than the temperature of the crystallization section 15 and higher than room temperature by hot air supplied from an air intake port (not shown). Room temperature refers to the ambient temperature of the coating device 10.

[0028] Each of the three pressure adjustment chambers 17, 18, and 19 is a zone for eliminating the pressure difference between the zones on either side of the pressure adjustment chambers 17, 18, and 19. By eliminating the pressure difference between the zones on either side of each pressure adjustment chamber 17, 18, and 19, air flow between the zones on either side of the pressure adjustment chambers 17, 18, and 19 becomes less likely to occur, and conditions such as temperature are maintained in those zones.

[0029] The coating device 10 also includes a control unit 29 (see FIG. 3) that controls the unwinding unit 11, the surface treatment unit 12, the coating unit 13, the solvent removal unit 14, the crystallization unit 15, the winding unit 16, and the pressure adjustment chambers 17 to 19. The control unit 29 executes control to carry out the coating method described below.

[0030] (2) Coating method using the coating device 10 During operation of the coating device 10, a single long substrate 1 is unwound from a take-up shaft 20 in the unwinding section 11, and is wound around a take-up shaft 28 in the winding section 16. As a result, the substrate 1 is continuously transported through the surface treatment section 12, the coating section 13, the first pressure adjustment section 17, the solvent removal section 14, the second pressure adjustment section 18, the crystallization section 15, the third pressure adjustment section 19, and the winding section 16, in that order. The transport speed of the substrate 1 from the unwinding section 11 to the winding section 16 is adjusted as appropriate, but is, for example, 5 m / min or more and 20 m / min or less.

[0031] In the surface treatment section 12, the substrate 1 is irradiated with excimer light, thereby performing a surface treatment on the coated surface of the substrate 1. Details of the surface treatment will be described later.

[0032] In the coating section 13, a coating liquid is ejected from a die 21 toward the surface-treated substrate 1, and the coating liquid is applied to the coating surface of the substrate 1. The thickness of the coating liquid on the coating surface is preferably 20 μm or less, and more preferably 10 μm or less.

[0033] In the solvent removal section 14, the substrate 1 is transported on the transport rollers 23 with the surface on which the coating liquid has been applied facing up. Thereafter, the substrate 1 is transported horizontally with the surface on which the coating liquid has been applied facing up until just before it is taken up by the take-up shaft 28 in the take-up section 16.

[0034] In the solvent removal section 14, the substrate 1 coated with the coating liquid is transported over a plurality of transport rollers 23. As the substrate 1 is transported through the solvent removal section 14, an infrared irradiation device 24 above irradiates it with infrared light of a wavelength that is absorbed by the solvent but not easily absorbed by the perovskite precursor. This causes the solvent in the coating liquid to evaporate through radiation and be removed from the substrate 1. Note that, although the temperature of the coating liquid rises to a temperature at which the solvent evaporates (for example, around 80°C) due to the infrared irradiation, it does not rise to a temperature at which the perovskite precursor crystallizes and forms a coating film (for example, around 100°C). Therefore, no perovskite layer is formed in the solvent removal section 14.

[0035] In the crystallization section 15, the substrate 1 from which the solvent has been removed is transported on a plurality of transport rollers 25. During the transport, the perovskite precursor is heated and crystallized on the substrate 1 by hot air from a nozzle 26, becoming perovskite, and a perovskite layer is formed.

[0036] In the winding section 16, the perovskite laminate 2, in which a perovskite layer is formed on the substrate 1, is wound around a winding shaft 28 and finally formed into a large roll. In the winding section 16, the perovskite layer is heated at a temperature lower than that in the crystallization section 15, thereby relaxing the stress in the perovskite layer. The large roll of the perovskite laminate 2 is taken out of the winding section 16.

[0037] The perovskite stack 2 taken out from the winding section 16 is transported to another device, where a hole transport layer and a back electrode are laminated on the perovskite layer in the perovskite stack 2 to form a perovskite solar cell.

[0038] (3) Configuration of the surface treatment unit 12 (surface treatment unit) As shown in FIG. 2, the surface treatment section 12 is provided with a surface treatment chamber 30 surrounded by walls, a first drive roller 34 arranged upstream of the surface treatment chamber 30 in the conveying direction of the substrate 1 (toward the unwinding section 11), a second drive roller 35 arranged downstream of the surface treatment chamber 30 in the conveying direction of the substrate 1 (toward the coating section 13), and a tension measurement roller 36 arranged between the surface treatment chamber 30 and the second drive roller 35.

[0039] The first drive roller 34 and the second drive roller 35 are rotated by the force of a motor (not shown), thereby transporting the substrate 1 in the surface treatment section 12. The tension measurement roller 36 is provided with a tension measurement device 37 for measuring the tension of the substrate 1.

[0040] An upstream opening 31 is formed in the wall of the surface treatment chamber 30 on the upstream side (the unwinding section 11 side) in the conveying direction of the substrate 1, and a downstream opening 32 is formed in the wall on the downstream side (the coating section 13 side) in the conveying direction of the substrate 1. The substrate 1 that has passed through the first drive roller 34 passes through the upstream opening 31 and enters the surface treatment chamber 30. The substrate 1 also passes through the downstream opening 32 and leaves the surface treatment chamber 30, and is conveyed to the tension measuring roller 36 side.

[0041] Five rollers are provided in the surface treatment chamber 30. The five rollers are two upper and lower rollers (an upper first roller 41 and a lower second roller 42) provided on the right side (the upstream opening 31 side) in Fig. 2, two upper and lower rollers (a lower fourth roller 44 and an upper fifth roller 45) provided on the left side (the downstream opening 32 side) in Fig. 2, and a third roller 43 provided in the center in the left-right direction in Fig. 2 and below the second roller 42 and the fourth roller 44.

[0042] The first drive roller 34, the second drive roller 35, the tension measuring roller 36, and the first to fifth rollers 41 to 45 have their rotation axes parallel to one another.

[0043] Within the surface treatment chamber 30, the substrate 1 contacts the left side of the first roller 41, the right side of the second roller 42, the underside of the third roller 43, the left side of the fourth roller 44, and the right side of the fifth roller 45, and is transported in an approximately U-shape overall.

[0044] Because the substrate 1 is transported in this manner, the gap between two adjacent rollers is a small section in which the substrate 1 is transported in one direction. Specifically, the gap between the first roller 41 and the second roller 42 is a first small section 51, the gap between the second roller 42 and the third roller 43 is a second small section 52, the gap between the third roller 43 and the fourth roller 44 is a third small section 53, and the gap between the fourth roller 44 and the fifth roller 45 is a fourth small section 54.

[0045] 2, the conveying direction of the substrate 1 is different between two adjacent small sections. Specifically, the conveying direction of the substrate 1 is different between the first small section 51 and the second small section 52, between the second small section 52 and the third small section 53, and between the third small section 53 and the fourth small section 54.

[0046] Furthermore, the base material 1 bends at the roller positions at both ends of each small section. For example, the base material 1 bends at the positions of the first roller 41 and the second roller 42 at both ends of the first small section 51.

[0047] One excimer lamp 40 is provided for each of these small sections 51 to 54. Although not shown, the excimer lamp 40 includes a tubular light-emitting body that emits excimer light, a mirror that reflects and diffuses the excimer light emitted from the light-emitting body, a housing that houses the light-emitting body and the mirror, and a light-transmitting plate that transmits the excimer light emitted from the light-emitting body and diffused by the mirror to the outside of the housing. The surface of this light-transmitting plate (the surface facing the outside of the housing) is a flat surface that forms the rectangular light-emitting surface of the excimer lamp 40. Excimer light of uniform intensity is emitted from the light-emitting surface of the excimer lamp 40 regardless of location.

[0048] As shown in FIG. 2, each excimer lamp 40 is disposed in a position facing the substrate 1 being transported through each of the small sections 51 to 54. Each excimer lamp 40 is disposed so that its light-emitting surface faces the substrate 1 and is parallel to the substrate 1. The width of the light-emitting surface of each excimer lamp 40 is equal to or greater than the width of the substrate 1. Note that the width of the light-emitting surface refers to the length in the same direction as the width direction of the substrate 1. With this configuration, the excimer light emitted from each excimer lamp 40 is irradiated with uniform intensity over the entire width direction of the substrate 1. Of both surfaces of the substrate 1, the surface irradiated with the excimer light is the coating surface onto which the coating liquid is applied in the coating section 13.

[0049] Because excimer light is easily absorbed by oxygen and water in the air and is easily attenuated, the distance between the light-emitting surface of the excimer lamp 40 and the coated surface of the substrate 1 is set to a predetermined short length. Specifically, the distance between the light-emitting surface of the excimer lamp 40 and the coated surface of the substrate 1 is preferably 0.5 mm or more and 3.0 mm or less, and more preferably 0.5 mm or more and 1.5 mm or less.

[0050] In each of the small sections 51 to 54, at least one of the excimer lamp 40 and the rollers 41 to 45 can be displaced so that the distance between the light-emitting surface of the excimer lamp 40 and the coated surface of the substrate 1 is the predetermined length and so that the light-emitting surface of the excimer lamp 40 and the coated surface of the substrate 1 are parallel to each other. For example, an excimer lamp moving device 46 (see FIG. 3) that can independently move each of the multiple excimer lamps 40 and a roller moving device 47 (see FIG. 3) that can independently move each of the first to fifth rollers 41 to 45 are provided. The excimer lamp moving device 46 can change the distance between the excimer lamp 40 and the substrate 1 and can change the angle of the light-emitting surface relative to the normal direction of the substrate 1. The roller moving device 47 can change the distance between the rotation axes of the first to fifth rollers 41 to 45 and the substrate 1 and can tilt these rotation axes relative to the substrate 1.

[0051] As shown in FIG. 3 , the control unit 29 is connected to the first drive roller 34, the second drive roller 35, the tension measuring device 37, the excimer lamp 40, the excimer lamp moving device 46, the roller moving device 47, and the like. Based on the tension of the substrate 1 measured by the tension measuring device 37, the control unit 29 controls the position and inclination of the first drive roller 34 or other rollers, etc., to control the tension of the substrate 1 in the surface treatment unit 12 to a predetermined magnitude so that the substrate 1 does not slacken in each of the small sections 51 to 54. The control unit 29 also controls at least one of the excimer lamp moving device 46 and the roller moving device 47 to make the light-emitting surface of the excimer lamp 40 parallel to the substrate 1 and to set the distance between the light-emitting surface of the excimer lamp 40 and the substrate 1 to a predetermined length in each of the small sections 51 to 54.

[0052] Although not shown, the control unit 29 is also connected to devices and sensors for controlling the unwinding unit 11, the surface treatment unit 12, the coating unit 13, the solvent removal unit 14, the crystallization unit 15, the winding unit 16, and the pressure adjustment chambers 17 to 19.

[0053] An exhaust port 33 is formed in the wall of the surface treatment chamber 30. In the surface treatment chamber 30, ozone is generated by irradiating oxygen in the air with excimer light, and the ozone is exhausted from the exhaust port 33.

[0054] (4) Surface treatment method in the surface treatment section 12 Before the coating device 10 is put into operation, the light-emitting surface of the excimer lamp 40 and the surface to be coated of the substrate 1 are adjusted so that they are parallel to each other and have a predetermined distance between them. After the adjustment is complete, the coating device 10 is put into operation.

[0055] During operation of the coating device 10, the control unit 29 continuously conveys the long substrate 1 at a predetermined conveying speed (preferably a constant conveying speed, for example, 5 m / min to 20 m / min) in the surface treatment unit 12. In Fig. 2, the conveying direction of the substrate 1 in the surface treatment unit 12 and the rotation direction of the rollers for conveyance are indicated by arrows.

[0056] While the substrate 1 is being transported in the surface treatment section 12, the control section 29 controls the tension of the substrate 1 in the surface treatment chamber 30 to be maintained at a predetermined level based on the tension of the substrate 1 measured by the tension measuring device 37. Furthermore, while the substrate 1 is being transported in the surface treatment section 12, the control section 29 keeps each excimer lamp 40 in the surface treatment section 12 lit.

[0057] Through these controls by the control unit 29, the substrate 1 is continuously transported at a predetermined transport speed in each of the small sections 51-54 of the surface treatment unit 12 in a tensioned state without slack. The substrate 1 then passes through the areas where each excimer lamp 40 is irradiating excimer light at the predetermined transport speed. During this passage, the coated surface of the substrate 1 is irradiated with excimer light. During the irradiation of excimer light, the distance between the light-emitting surface of each excimer lamp 40 and the coated surface of the substrate 1 is maintained at a predetermined length.

[0058] The surface treatment of the coated surface of the substrate 1 is carried out by irradiating it with excimer light in this way. Specifically, organic matter on the coated surface of the substrate 1 is decomposed by the excimer light, which has a short wavelength and high energy. Furthermore, ozone and active oxygen are generated when oxygen in the air is irradiated with excimer light. The decomposed organic matter then combines with the ozone and active oxygen on the coated surface of the substrate 1, vaporizes, and is removed. This modifies the coated surface of the substrate 1, improving its wettability.

[0059] The contact angle of the coating liquid when it comes into contact with the coated surface of the substrate 1 is large before surface treatment, for example, 90° or more. This contact angle is preferably reduced to 20° or less, and more preferably 10° or less, by the surface treatment in the surface treatment section 12. Such a contact angle prevents the coating liquid from being repelled by the coated surface, and maintains a thin coating liquid layer, even when the coating liquid layer is as thin as 20 μm or less (or 10 μm or less). The "contact angle" is one of the indicators used to evaluate wettability. It quantifies the shape (height and width) of the droplet formed when a liquid is dropped onto a solid. Specifically, the liquid on the solid surface is observed from the side, and the angle between the tangent of the droplet outline at the end point of the droplet and the solid surface is measured. If the surface is easily wetted, it will be flat (the contact angle will be small), while if it is difficult to wet, it will be closer to a sphere (the contact angle will be large).

[0060] The preferred cumulative light intensity of the excimer light irradiated onto the substrate 1 in the surface treatment section 12 is 1000 mJ / cm 2 More than 10000mJ / cm 2 The more preferable cumulative light dose is 5000 mJ / cm 2 More than 7000mJ / cm 2 The integrated light amount is as follows. Such an integrated light amount sufficiently modifies the coating surface of the substrate 1. The integrated light amount can be set within a predetermined range by adjusting the transport speed of the substrate 1, the output level from the excimer lamp 40, the distance between the light-emitting surface of the excimer lamp 40 and the coating surface of the substrate 1, and the like. The exact value of the optimal integrated light amount depends on the composition of the solvent in the coating liquid.

[0061] (5) Effects of this embodiment As described above, the surface treatment section 12 of the coating device 10 of this embodiment is provided with the excimer lamp 40. The excimer lamp 40 emits excimer light toward the coating surface of the substrate 1 being transported through the surface treatment section 12. This causes the surface treatment of the coating surface of the substrate 1 to be performed.

[0062] Compared to ultraviolet light from a low-pressure mercury lamp, excimer light can achieve a surface treatment effect with extremely short irradiation times. Furthermore, although excimer light is prone to attenuation, by maintaining a predetermined distance between the light-emitting surface of the excimer lamp 40 and the coated surface of the substrate 1, sufficient excimer light can be irradiated onto the coated surface of the substrate 1. For these reasons, the coating device 10 of this embodiment can perform sufficient surface treatment on the coated surface of the substrate 1 (for example, surface treatment such that the contact angle of the coating liquid when it comes into contact with the coated surface of the substrate 1 is 20° or less).

[0063] Then, a coating liquid is applied to the surface of the substrate 1 after the surface treatment in the coating unit 13. The surface of the substrate 1 immediately before the coating liquid is applied has been sufficiently modified by the surface treatment to improve wettability, so the coating liquid is applied evenly and without unevenness. As a result, the perovskite layer generated from the coating liquid is an even layer without unevenness.

[0064] Here, the surface treatment using excimer light is unlikely to roughen or alter the surface of the irradiated object, and it is not a treatment that penetrates into the irradiated object and changes the properties of the irradiated object. Therefore, according to this embodiment, problems such as roughening of the coated surface of the substrate 1 are unlikely to occur.

[0065] Furthermore, the coating apparatus 10 of this embodiment is a so-called roll-to-roll coating apparatus 10 that includes an unwinding section 11 that unwinds the substrate 1 and a winding section 16 that winds up the substrate 1 (perovskite laminate 2) coated with the coating liquid into a roll. Therefore, the hardness of the coated surface of the substrate 1 is low enough to allow it to be wound up. If such a substrate 1 is subjected to a corona treatment or plasma treatment, the coated surface of the substrate 1 may become rough. However, in this embodiment, the surface treatment is performed by irradiating it with excimer light, so the coated surface of the substrate 1 is less likely to become rough. Furthermore, in the coating apparatus 10, the substrate 1 passes in front of the excimer lamp 40 in a short time, and because excimer light can achieve a surface treatment effect with a short irradiation time, a sufficient surface treatment effect can be achieved in this embodiment.

[0066] Furthermore, since the substrate 1 of this embodiment is a resin film on which a transparent electrode and an electron transport layer are laminated, it cannot be heated to high temperatures, making it difficult to harden the electron transport layer. Therefore, if the electron transport layer, which is the coated surface of the substrate 1, is subjected to a corona treatment or plasma treatment, the electron transport layer will become rough. However, in this embodiment, the electron transport layer, which is the coated surface, is irradiated with excimer light, so the electron transport layer is less likely to become rough.

[0067] In addition, in the surface treatment section 12, the distance between the coated surface of the substrate 1 being transported and the light-emitting surface of the excimer lamp 40 is 0.5 mm or more and 3.0 mm or less, so that the excimer light emitted from the excimer lamp 40 can sufficiently reach the coated surface of the substrate 1.

[0068] Furthermore, in the surface treatment section 12, the light-emitting surfaces of the excimer lamps 40 are flat surfaces parallel to the coated surface of the transported substrate 1, so that the excimer light is irradiated evenly over a wide area of ​​the substrate 1. Furthermore, because the width of the light-emitting surfaces of the excimer lamps 40 is equal to or greater than the width of the substrate 1, the excimer light is irradiated evenly over the entire width direction of the coated surface of the substrate 1.

[0069] In addition, in the surface treatment section 12, at least one of the rollers 41 to 45 that transport the substrate 1 and the excimer lamp 40 is displaceable, so that the distance between the coated surface of the substrate 1 and the light-emitting surface of the excimer lamp 40 can be adjusted. The surface treatment section 12 applies an integrated light amount of 1000 mJ / cm 2 to the coated surface of the substrate 1. 2 More than 10000mJ / cm 2 By irradiating the substrate with the following excimer light, the coated surface of the substrate 1 is sufficiently modified.

[0070] Furthermore, in the surface treatment section 12, the gap between two adjacent rollers is each of small sections 51 to 54 in which the substrate 1 is transported in one direction. The transport direction of the substrate 1 differs between two adjacent small sections. This allows the substrate 1 to be stretched straight and without slack in each of the small sections 51 to 54. Because the substrate 1 does not slacken, the distance between the light-emitting surface of the excimer lamp 40 provided for each small section and the coated surface of the substrate 1 is easily maintained at a predetermined length.

[0071] (6) Example of change Various modifications can be made to the above embodiment.

[0072] Perovskite solar cells can have a mesoporous structure as shown in FIG. 4(a), a forward structure as shown in FIG. 4(b), and an inverted structure as shown in FIG. 4(c). In these figures, the surface exposed to sunlight is the bottom surface. The mesoporous structure is a structure in which a transparent electrode 4, an electron transport layer 5, a mesoporous titanium oxide layer 6, a perovskite layer 7, a hole transport layer 8, and a back electrode 9 are stacked in this order. The forward structure is a structure in which a transparent electrode 4, an electron transport layer 5, a perovskite layer 7, a hole transport layer 8, and a back electrode 9 are stacked in this order. The inverted structure is a structure in which a transparent electrode 4, a hole transport layer 8, a perovskite layer 7, an electron transport layer 5, and a back electrode 9 are stacked in this order. Any of the layers in any of these structures can be formed using the coating apparatus and coating method of the above-described embodiment.

[0073] For example, in forming the transparent electrode 4, a resin film is transported as a substrate, and the above-mentioned surface treatment is performed on one side of the film, which is the coated surface, in the surface treatment section 12.A coating liquid is then applied to the coated surface after the surface treatment, and the coating liquid solidifies to form the transparent electrode 4.

[0074] Furthermore, when forming a layer above the transparent electrode 4, the layer to be formed (referred to in this paragraph as the "upper layer") and the layer immediately below it (referred to in this paragraph as the "lower layer") are stacked together and transported as a substrate, and the surface treatment described above is performed on the coated surface, which is the surface of the lower layer, in the surface treatment section 12, and a coating liquid is applied to the coated surface after the surface treatment, and the coating liquid solidifies to become the upper layer.

[0075] Furthermore, the number and arrangement of rollers and excimer lamps in the surface treatment section 12 are not limited to those shown in Fig. 2. Furthermore, the overall configuration of the coating device 10 is not limited to that shown in Fig. 1.

[0076] Although one embodiment of the present invention and its modifications have been described above, these are merely examples and are not intended to limit the scope of the invention. Various omissions, substitutions, and modifications can be made to these examples without departing from the spirit of the invention. The above-described embodiment, its modifications, and any further modifications thereto are included within the scope of the invention as defined in the claims. [Explanation of symbols]

[0077] 1...substrate, 2...perovskite laminate, 4...transparent electrode, 5...electron transport layer, 6...mesoporous titanium oxide layer, 7...perovskite layer, 8...hole transport layer, 9...back electrode, 10...coating device, 11...unwinding section, 12...surface treatment section, 13...coating section, 14...solvent removal section, 15...crystallization section, 16...winding section, 17...first pressure adjustment chamber, 18...second pressure adjustment chamber, 19...third pressure adjustment chamber, 20...winding shaft, 21...die, 22...backup roller, 23...conveyor roller, 24...infrared irradiation device, 25...conveyor roller, 2 6...nozzle, 27...suction port, 28...winding shaft, 29...control unit, 30...surface treatment chamber, 31...upstream opening, 32...downstream opening, 33...exhaust port, 34...first drive roller, 35...second drive roller, 36...tension measuring roller, 37...tension measuring device, 40...excimer lamp, 41...first roller, 42...second roller, 43...third roller, 44...fourth roller, 45...fifth roller, 46...excimer lamp moving device, 47...roller moving device, 51...first small section, 52...second small section, 53...third small section, 54...fourth small section

Claims

1. a surface treatment unit that performs surface treatment on one of the coating surfaces of the long substrate; a coating unit that applies a coating liquid to the coated surface of the substrate after the surface treatment; In a coating device comprising: the coating liquid is a coating liquid that forms a perovskite layer or a mesoporous titanium oxide layer in a perovskite solar cell, the coated surface of the substrate is a surface of a layer that will come into contact with a layer of the coating liquid in the perovskite solar cell having a layered structure, the surface treatment section includes a roller for transporting the substrate and an excimer lamp for irradiating the coated surface of the substrate being transported with excimer light, a predetermined distance is maintained between the coated surface of the substrate being conveyed by the roller and the light-emitting surface of the excimer lamp; The surface treatment section applies an integrated light amount of 1000 mJ / cm ２ More than 10000mJ / cm ２ Irradiating the excimer light as follows: Coating equipment.

2. 2. The coating device according to claim 1, wherein the distance between the substrate being transported by the roller and the light emitting surface of the excimer lamp is 0.5 mm or more and 3.0 mm or less.

3. 3. The coating device according to claim 1, wherein at least one of the roller and the excimer lamp is displaceable so that the gap between the substrate being transported by the roller and the light-emitting surface of the excimer lamp is maintained at the predetermined length.

4. In the surface treatment section, the substrate is transported at a speed of 5 m / min or more and 20 m / min or less, In the surface treatment section, the surface treatment is performed so that the contact angle of the coating liquid coming into contact with the coated surface after the surface treatment is 20° or less; In the coating section, the coating liquid is applied to the coating surface to a thickness of 20 μm or less. The coating device according to claim 1 or 2.

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