Perovskite film forming apparatus and method for forming perovskite film

Abstract

An apparatus capable of forming a high-quality perovskite film is provided. [Solution] In an embodiment of a perovskite film forming apparatus 10, a solution containing a perovskite precursor and a solvent is applied to a substrate 1, and the perovskite precursor is crystallized to form a perovskite film on the substrate 1. The perovskite film forming apparatus 10 is characterized in that it is provided with a solvent removal chamber 14, which is a zone through which the substrate 1 passes, in which the solvent is removed from the solution applied to the substrate 1 without crystallizing the perovskite precursor, and a crystallization chamber 15, which is a zone through which the perovskite precursor is crystallized on the substrate 1 after passing through the solvent removal chamber 14 to form a perovskite film.

Description

[Technical field]

[0001] The present invention relates to a perovskite film forming apparatus and a perovskite film forming method. [Background technology]

[0002] In recent years, perovskite solar cells have attracted attention as a type of solar cell that is thin, lightweight, and expected to have high power generation efficiency. Perovskite solar cells generate electricity by absorbing sunlight in a perovskite film and generating free electrons and holes.

[0003] In the method for producing a perovskite film, a solution is first applied to a substrate. This application method is a so-called spin coating method in which a solution containing a perovskite precursor and a solvent is discharged onto the substrate, and the substrate is rotated to spread the solution on the substrate. The substrate on which the solution has been applied is then heated by a hot plate to remove the solvent and crystallize the perovskite precursor to form a perovskite film.

[0004] In addition, as described in Patent Document 1, it has also been proposed to apply a solution to a substrate from a moving nozzle, place the substrate after application in a reduced pressure environment to volatilize the solvent and promote crystallization of the perovskite precursor into perovskite (i.e., perovskite formation), and then place the substrate in a heated environment to further promote perovskite formation. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2024-14770 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, in each of the above methods, the evaporation of the solvent and the formation of the perovskite occur simultaneously, which causes non-uniform crystallinity that leads to reduced power generation efficiency and the formation of defects (voids) that cause short circuits. The current situation, in which it is difficult to form high-quality perovskite films, is preventing the widespread use of perovskite solar cells.

[0007] There have also been attempts to improve the quality of perovskite films by modifying the solution, such as adding an ionic liquid to a solution containing a perovskite precursor, or the antisolvent method, in which a poor solvent is dropped onto the solution on the substrate during spin coating. However, all of these methods were formation methods used in university experiments or at the research and development stage in companies, and were not methods for mass-producing perovskite films, which is necessary for the widespread use of perovskite solar cells.

[0008] The present invention has been made in view of the above circumstances, and has an object to provide an apparatus and method capable of mass-producing high-quality perovskite films. [Means for solving the problem]

[0009] In an embodiment of a perovskite film formation apparatus, a solution containing a perovskite precursor and a solvent is applied to a substrate, and the perovskite precursor is crystallized to form a perovskite film. The perovskite film formation apparatus includes a solvent removal chamber, which is a zone through which the substrate passes while being continuously transported, in which the solution on the substrate is heated to a temperature at which the solvent evaporates and the perovskite precursor does not crystallize, thereby removing the solvent from the solution applied to the substrate without crystallizing the perovskite precursor, and a crystallization chamber, which is a zone through which the perovskite precursor is heated to a crystallization temperature or higher on the substrate from which the solvent has been removed after passing through the solvent removal chamber, thereby crystallizing the perovskite precursor to form the perovskite film. the solvent and the perovskite precursor absorb different wavelengths of infrared light, the solvent removal chamber is provided with an infrared irradiator that irradiates infrared light of a specific wavelength that is absorbed by the solvent, the infrared irradiator irradiates the solution with infrared light of the specific wavelength to evaporate the solvent and heat the solution at a temperature at which the solvent evaporates and the perovskite precursor does not crystallize, thereby evaporating and removing the solvent without crystallizing the perovskite precursor, the solvent removal chamber is provided with transport rollers that transport the substrate placed thereon, the transport rollers transport the substrate with the surface on which the solution is applied facing up, and a roller cooling device is provided for cooling the transport rollers. .

[0010] Further, in a perovskite film formation method according to an embodiment, a solution containing a perovskite precursor and a solvent is applied to a substrate, and the perovskite precursor is crystallized to form a perovskite film, the method comprising the steps of: heating the solution on the substrate to a temperature at which the solvent evaporates and the perovskite precursor does not crystallize, thereby removing the solvent from the solution applied to the substrate without crystallizing the perovskite precursor; and, after the solvent removal step, heating the perovskite precursor to a crystallization temperature or higher on the substrate from which the solvent has been removed, thereby crystallizing the perovskite precursor to form the perovskite film. The wavelength of infrared light absorbed by the solvent and the perovskite precursor differ from each other, and in the step of removing the solvent, an infrared irradiator irradiates the solution with infrared light of a specific wavelength absorbed by the solvent to heat the solution, thereby evaporating and removing the solvent without crystallizing the perovskite precursor, and the step of removing the solvent is performed while a conveying roller conveys the substrate with the substrate placed thereon, and in the step of removing the solvent, the conveying roller conveys the substrate with the surface on which the solution is applied facing up, and cools the substrate from the underside. It is characterized by: Effect of the Invention

[0011] According to the above-mentioned perovskite film forming apparatus, a high-quality perovskite film can be formed and mass-produced by passing a substrate through a solvent removal chamber and a crystallization chamber in order. According to the above-mentioned perovskite film forming method, a high-quality perovskite film can be formed and mass-produced by crystallizing a perovskite precursor after removing a solvent from a solution applied to a substrate. [Brief description of the drawings]

[0012] [Figure 1] FIG. 2 is a side view of a perovskite film forming apparatus. [Diagram 2] FIG. 2 is a side view of a substrate having a solution applied thereto. [Diagram 3] FIG. [Figure 4] Side view of the crystallization chamber. [Diagram 5] FIG. 1 is a block diagram of a perovskite film formation apparatus. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] A perovskite film forming apparatus 10 according to one embodiment of the present invention will be described with reference to Fig. 1 to Fig. 5. In the following description, the side in the direction of travel of a long-sized substrate 1 is referred to as the front, and the opposite side is referred to as the rear. Furthermore, left and right refer to the left and right when viewed from the front to the rear.

[0014] (1) Overall configuration of perovskite film forming apparatus 10 As shown in FIG. 1, the perovskite film forming apparatus 10 is configured with a coating chamber 13, a solvent removal chamber 14, a crystallization chamber 15, and an annealing chamber 16 arranged side by side from the rear to the front. A first pressure adjustment chamber 17 is provided between the coating chamber 13 and the solvent removal chamber 14, a second pressure adjustment chamber 18 is provided between the solvent removal chamber 14 and the crystallization chamber 15, and a third pressure adjustment chamber 19 is provided between the crystallization chamber 15 and the annealing chamber 16. Each of the pressure adjustment chambers 17, 18, and 19 is separated from the adjacent areas on both sides by partition walls 29 (see FIGS. 3 and 4) having openings through which the substrate 1 can pass. The perovskite film forming apparatus 10 also includes an unwinding section 11 and a surface treatment section 12.

[0015] (2) Configuration of the unwinding section 11 and the surface treatment section 12 The unwinding section 11 is provided with a winding shaft 20. The substrate 1 before being coated with a solution is wound around the winding shaft 20. The winding shaft 20 rotates by driving a motor to unwind the substrate 1. The substrate 1 before being coated with a solution is formed by laminating a transparent conductive film and an electron transport layer on a transparent film such as a polyethylene terephthalate film. The width of the substrate 1 is, for example, 200 mm to 1000 mm.

[0016] The surface treatment section 12 is a section that performs a surface treatment on the substrate 1 transported from the unwinding section 11. The surface treatment is a treatment for improving the wettability of the electron transport layer of the substrate 1, and is, for example, any one of a corona treatment, a plasma treatment, a UV treatment, etc. In addition, the surface treatment section 12 also removes dust from the substrate 1.

[0017] (3) Configuration of Coating Chamber 13 The coating chamber 13 is provided with a die 21 and a backup roller 22 in front of the die 21. The backup roller 22 is one of the rollers that transport the substrate 1, and is rotated by being driven by a motor. The rotation axis of the backup roller 22 extends in the left-right direction. The substrate 1 transported from the surface treatment section 12 located below the backup roller 22 changes its transport direction at the backup roller 22 and is transported forward. In the vicinity of the die 21, the backup roller 22 transports the substrate 1 from bottom to top.

[0018] The die 21 ejects the solution toward the substrate 1 in contact with the backup roller 22, and applies the solution to a preset coating thickness over the entire width direction (left-right direction) of the substrate 1. The surface of the substrate 1 to which the solution is applied is the upper surface in the solvent removal chamber 14 and the crystallization chamber 15.

[0019] For reference, a state in which the solution is applied onto the substrate 1 to form a solution layer 2 is shown in Fig. 2. Fig. 2 is a diagram showing the substrate 1 immediately after it enters the solvent removal chamber 14. Note that in this specification, the substrate 1 after the solution has been applied thereto may also be referred to simply as "substrate 1".

[0020] The solution contains a perovskite precursor and a solvent. The perovskite precursor is a material in a stage before it crystallizes to become a perovskite. For example, when it is intended to generate lead methylammonium iodide CH3NH3PbI3 as a perovskite, lead iodide PbI2 and methylammonium iodide CH3NH3I are used as the perovskite precursor. In addition, the solvent is one that absorbs infrared rays with a clear wavelength, for example, one that absorbs infrared rays with a wavelength of 10 μm or less. The solvent and the perovskite precursor absorb infrared rays with different wavelengths. The absorption of infrared rays with different wavelengths means that the infrared absorption spectra are different. Specific examples of the solvent include N-N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO).

[0021] (4) Configuration of the solvent removal chamber 14 The solvent removal chamber 14 is shown in FIG. 3. The solvent removal chamber 14 has a rectangular parallelepiped exterior shape, is thermally insulated, and is isolated from other areas. The solvent removal chamber 14 also has an entrance for the substrate 1 at the rear and an exit for the substrate 1 at the front. In the solvent removal chamber 14, multiple transport rollers 30 are lined up in the front-rear direction. Each transport roller 30 is rotated by a motor. The rotation axis of each transport roller 30 extends in the left-right direction. These transport rollers 30 transport the substrate 1 on top of them. The transport rollers 30 also have the role of keeping the substrate 1 horizontal so that the applied solution does not flow.

[0022] A roller cooling device 33 (see FIG. 5) is provided to cool at least the outer circumferential surfaces of the plurality of conveying rollers 30. Although not shown, the roller cooling device 33 includes a fluid flow path formed inside the conveying roller 30 and a circulation device for circulating a fluid (e.g., water or air) through the flow paths. Alternatively, the roller cooling device 33 includes Peltier elements provided on each of the conveying rollers 30 and a power source for applying electricity to the Peltier elements.

[0023] The roller cooling device 33 cools the transport roller 30, thereby cooling the substrate 1 (see FIG. 2) placed on the transport roller 30 from the bottom side. As will be described next, in the solvent removal chamber 14, the solvent evaporates from the solution layer 2 on the substrate 1, and at that time, the latent heat of evaporation is removed from the surface (upper surface) of the solution layer 2. The cooling capacity of the roller cooling device 33 is set so that the cooled transport roller 30 can remove from the substrate 1 an amount of heat equal to the amount of latent heat removed at this time.

[0024] An infrared irradiator 31 is provided above the transport roller 30 in the solvent removal chamber 14. The infrared irradiator 31 is a device that irradiates infrared rays of a wavelength that is absorbed by the solvent and is not easily absorbed by the perovskite precursor. When a solvent that absorbs infrared rays with a wavelength of 10 μm or less is used, the infrared irradiator 31 that irradiates infrared rays with a wavelength of 10 μm or less is used. Such an infrared irradiator 31 that irradiates infrared rays in a specific wavelength range is realized by combining a device that irradiates infrared rays in a wider wavelength range with a filter that passes only infrared rays in a specific wavelength range (for example, a low-pass filter that passes only infrared rays with a wavelength of 10 μm or less).

[0025] The infrared irradiator 31 is sufficiently large in the front-rear and left-right directions (for example, formed in a flat shape) and can irradiate infrared rays over a wide range in the front-rear direction and the entire left-right direction (width direction) of the substrate 1. The length of the infrared irradiator 31 in the left-right direction is preferably long enough to uniformly irradiate the substrate 1 with infrared rays. For example, the length is preferably longer than the length of the substrate 1 in the left-right direction and further preferably longer than the length of the transport roller 30 in the left-right direction.

[0026] 3, the substrate 1 is irradiated with infrared rays from the infrared irradiation device 31, and the solvent in the solution is evaporated by radiation. By irradiating the infrared rays, the temperature of the solution becomes higher than the atmospheric temperature in the solvent removal chamber 14 (for example, to about 70°C), but does not rise to a temperature at which the perovskite precursor crystallizes (for example, to about 100°C).

[0027] The atmospheric temperature in the solvent removal chamber 14 is sufficiently lower than the temperature at which the perovskite precursor crystallizes to form perovskite, and is, for example, 30°C to 50°C.

[0028] In addition, a straightening device is provided at a position above the transport rollers 30 in the solvent removal chamber 14. The straightening device is composed of an air blower 32a that blows air and an air suction device 32b that sucks in air. The air blower 32a is provided at a position above and behind the transport rollers 30 in the solvent removal chamber 14, and blows air forward and horizontally. The air suction device 32b is provided at the same height and in front of the air blower 32a in the solvent removal chamber 14, and sucks in air blown from the rear.

[0029] With this arrangement of the blower 32a and the suction device 32b, air is sent from the blower 32a to the suction device 32b, as shown by the solid arrow in Fig. 3. Therefore, air flows over the substrate 1 on the transport roller 30 in the same direction as the transport direction of the substrate 1. The speed of the air flow is controlled to be the same as the transport speed of the substrate 1. The temperature of the air sent from the blower 32a is the same as the temperature of the air in the solvent removal chamber 14, for example, 30°C to 50°C.

[0030] (5) Configuration of crystallization chamber 15 The crystallization chamber 15 is shown in FIG. 4. The crystallization chamber 15 has a rectangular parallelepiped exterior shape, is insulated, and is isolated from other areas. The crystallization chamber 15 has an entrance for the substrate 1 on the rear side and an exit for the substrate 1 on the front side. In the crystallization chamber 15, multiple transport rollers 40 are arranged in the front-rear direction. Each transport roller 40 is rotated by driving a motor. The rotation axis of each transport roller 40 extends in the left-right direction. These transport rollers 40 transport the substrate 1 placed thereon.

[0031] In the crystallization chamber 15, a plurality of nozzles 41 are arranged in the front-rear direction above the transport rollers 40. These nozzles 41 blow hot air onto the substrate 1 transported by the transport rollers 40, and heat the substrate 1 to a temperature at which the perovskite precursor crystallizes (for example, about 100°C) or higher to perform crystallization. Inside each nozzle 41 is a hot air flow path extending in the vertical direction. At the bottom of each nozzle 41, a front outlet 41a and a rear outlet 41b are formed. The front outlet 41a is an outlet that blows the hot air in the nozzle 41 obliquely forward and downward. The rear outlet 41b is an outlet that blows the hot air in the nozzle 41 obliquely backward and downward.

[0032] In addition, an intake port 42 for sucking in hot air from within the crystallization chamber 15 is provided above the transport roller 40. The intake ports 42 and the nozzles 41 are alternately arranged in the front-rear direction, and the intake ports 42 are disposed between adjacent nozzles 41. The intake ports 42 are located higher than the front outlet 41a and the rear outlet 41b of the nozzle 41. With this structure, the hot air blown obliquely downward from the front outlet 41a and the rear outlet 41b of the nozzle 41 rises in a relatively short time and is sucked into the intake port 42. The flow of the hot air is shown by arrows in FIG. 4. This flow of the hot air makes it difficult for the hot air to leak out of the crystallization chamber 15.

[0033] All the nozzles 41 and all the suction ports 42 are provided on the ceiling, not on the side surfaces, of the crystallization chamber 15. Therefore, in the crystallization chamber 15, hot air flows in the left-right direction are unlikely to occur, and temperature changes in the left-right direction are unlikely to occur.

[0034] The widths (length in the left-right direction) of the front outlet 41a, the rear outlet 41b and the suction port 42 are each approximately the same as the length of the transport roller 40 in the left-right direction, and are, for example, 100% to 120% of the length of the transport roller 40 in the left-right direction. This makes it easy to heat the entire crystallization chamber 15 in the width direction (left-right direction) uniformly. Note that the structure of the nozzle 41 is not limited to this structure, and any structure that can heat the substrate 1 uniformly may be used.

[0035] The temperature of the atmosphere in the crystallization chamber 15 is maintained at a substantially uniform temperature throughout the chamber 15. The temperature of the atmosphere in the crystallization chamber 15 is the temperature at which the perovskite precursor crystallizes, and is, for example, approximately 100°C.

[0036] An exhaust chamber 43 communicating with the suction port 42 is provided above the crystallization chamber 15. An air supply chamber 44 is provided surrounded by the exhaust chamber 43, and air supply paths 45 are provided from the air supply chamber 44 to each nozzle 41. Air taken in from outside the perovskite film-forming apparatus 10 is heated by a heater (not shown), and passes through the air supply chamber 44, the air supply path 45, and the nozzle 41 before being blown out into the crystallization chamber 15. The air sucked in from the suction port 42 passes through the exhaust chamber 43 and is exhausted to the outside of the perovskite film-forming apparatus 10.

[0037] (6) Configuration of annealing chamber 16 1, the annealing chamber 16 is provided with an air intake 51 for supplying hot air heated by a heater into the annealing chamber 16, and an exhaust 52 for exhausting the air inside the annealing chamber 16 to the outside of the annealing chamber 16. The hot air supplied from the air intake 51 maintains the atmospheric temperature of the annealing chamber 16 at a temperature lower than the temperature of the crystallization chamber 15 and higher than room temperature. The room temperature refers to the ambient temperature of the perovskite film formation apparatus 10 when the perovskite film formation apparatus 10 is in an operating state.

[0038] Further, a dehumidifier (not shown) is provided in the annealing chamber 16. The dehumidifier controls the humidity in the annealing chamber 16 to be, for example, 30% or less. It is preferable that dehumidifiers are also provided in the coating chamber 13, the solvent removal chamber 14, and the crystallization chamber 15, and that the humidity in each chamber is controlled to be, for example, 30% or less.

[0039] The annealing chamber 16 also serves as a winding section that winds up the perovskite film laminate 3 in which a perovskite film is formed on the substrate 1. A winding shaft 50 is disposed in the winding section. The winding shaft 50 is rotated by being driven by a motor, and winds up the perovskite film laminate 3.

[0040] (7) Configuration of pressure adjustment chambers 17, 18, 19 The second pressure adjustment chamber 18 located between the solvent removal chamber 14 and the crystallization chamber 15 will be described. As shown in Fig. 4, the second pressure adjustment chamber 18 is provided with an air inlet 23 and an exhaust port 24. The ducts leading to the air inlet 23 and the exhaust port 24 are provided with dampers 23a, 24a (see Fig. 5), respectively, and the amount of air supplied from the air inlet 23 and the amount of air exhausted from the exhaust port 24 can be controlled by controlling the dampers 23a, 24a. A fan may be provided in the duct.

[0041] Moreover, the solvent removal chamber 14 and the crystallization chamber 15, which are adjacent areas on both sides of the second pressure adjustment chamber 18, are provided with air pressure sensors 25a, 25b (see FIG. 5) for measuring air pressure, respectively.

[0042] The control unit 60, which will be described next, constantly monitors the difference between the atmospheric pressure of the solvent removal chamber 14 and the atmospheric pressure of the crystallization chamber 15, measured by the atmospheric pressure sensors 25a and 25b. When an atmospheric pressure difference occurs between these two zones (i.e., the solvent removal chamber 14 and the crystallization chamber 15), or when the atmospheric pressure difference between these two zones exceeds a predetermined value, the control unit 60 controls the dampers 23a and 24a to supply or exhaust air to the second pressure adjustment chamber 18, thereby substantially eliminating the atmospheric pressure difference between these two zones. For example, when the control unit 60 supplies air to the second pressure adjustment chamber 18, air supplied to the second pressure adjustment chamber 18 from the outside flows into the zone with the lower atmospheric pressure, thereby substantially eliminating the atmospheric pressure difference between the two zones. When the control unit 60 exhausts air from the second pressure adjustment chamber 18, air with the higher atmospheric pressure of the two zones passes through the second pressure adjustment chamber 18 and is exhausted to the outside, thereby substantially eliminating the atmospheric pressure difference between the two zones.

[0043] Since the difference in air pressure between the solvent removal chamber 14 and the crystallization chamber 15 is almost eliminated, there is almost no air flow between the solvent removal chamber 14 and the crystallization chamber 15, and conditions such as temperature are maintained in each of the solvent removal chamber 14 and the crystallization chamber 15.

[0044] The first pressure adjustment chamber 17 and the third pressure adjustment chamber 19 have the same structure as the second pressure adjustment chamber 18, and are controlled in the same manner as the second pressure adjustment chamber 18. This makes it difficult for air to flow between the adjacent zones of the pressure adjustment chambers 17, 19, and conditions such as temperature are maintained in those zones.

[0045] (8) Electrical configuration of the perovskite film forming apparatus 10 The perovskite film forming apparatus 10 includes a control unit 60 that is made up of a computer. As shown in Fig. 5, the control unit 60 is connected to the infrared ray irradiation device 31, the roller cooling device 33, the blower device 32a, the suction device 32b, the dampers 23a, 24a, and the air pressure sensors 25a, 25b. Although not shown, the control unit 60 is also connected to the respective motors that rotate the various rollers, a heater that heats the air, and the like. The control unit 60 controls the devices that are connected to it.

[0046] (9) Perovskite film formation method In this embodiment, one long sheet of substrate 1 is unwound from a winding shaft 20 at the unwinding section 11, and is wound around a winding shaft 50 at the annealing chamber 16. As a result, substrate 1 is continuously transported through the coating chamber 13, the first pressure adjustment chamber 17, the solvent removal chamber 14, the second pressure adjustment chamber 18, the crystallization chamber 15, the third pressure adjustment chamber 19, and the annealing chamber 16 in this order. The transport speed of substrate 1 from the unwinding section 11 to the annealing chamber 16 is appropriately adjusted, and is, for example, 5 to 20 m / min.

[0047] In the coating chamber 13, the solution is discharged from the die 21 toward the substrate 1 in contact with the backup roller 22, and the solution is applied to the surface of the substrate 1 on the electron transport layer side (the surface opposite to the film side).

[0048] In the solvent removal chamber 14, the substrate 1 is transported on a plurality of transport rollers 30. In the solvent removal chamber 14, the substrate 1 is oriented with the surface on which the solution has been applied facing up. Thereafter, the substrate 1 is transported horizontally with the surface on which the solution has been applied facing up until immediately before the substrate 1 is taken up by the take-up shaft 50 in the annealing chamber 16.

[0049] The substrate 1 being transported through the solvent removal chamber 14 is irradiated with infrared rays from an infrared irradiation device 31 above, the wavelength of which is absorbed by the solvent but not easily absorbed by the perovskite precursor. This causes the solvent in the solution to evaporate through radiation and be removed from the substrate 1. Note that the temperature of the solution rises to a temperature at which the solvent evaporates (for example, around 70°C) as a result of the infrared irradiation, but does not rise to a temperature at which the perovskite precursor crystallizes (for example, around 100°C). Therefore, perovskite is not produced in the solvent removal chamber 14.

[0050] When the solvent evaporates, the latent heat of evaporation is taken from the solution, and the temperature of the surface (upper surface) of the solution layer 2 drops. If the temperature of the substrate 1 side is high despite the drop in the surface temperature of the solution layer 2, convection occurs in the solution and Benard cells are generated. When the perovskite precursor crystallizes in a state where Benard cells have occurred, the boundaries of the cells become grain boundaries, and cracks are likely to occur at these grain boundaries. The term "Benard cells" refers to a regularly separated cellular convection structure that is generated when a thin layer of fluid is heated uniformly from below.

[0051] However, in the solvent removal chamber 14 of the present embodiment, the conveying rollers 30 are cooled by the roller cooling device 33, and the substrate 1 is cooled from the lower surface side by the conveying rollers 30. As a result, in the solution layer 2, the surface temperature and the temperature on the substrate 1 side become substantially equal, and convection is unlikely to occur in the solution.

[0052] In addition, above the substrate 1 being transported through the solvent removal chamber 14, the straightening device blows air in the same direction as the transport direction of the substrate 1, at a speed controlled to be the same as the transport speed of the substrate 1. This makes it difficult for air convection to occur above the solution layer 2 on the substrate 1, and makes it difficult for unevenness to form as wind ripples in the solution layer 2. Another effect is that the evaporated solvent is sucked into the air from the blower 32a by the air suction device 32b and discharged to the outside of the solvent removal chamber 14.

[0053] In the crystallization chamber 15, the substrate 1 from which the solvent has been removed is transported on a plurality of transport rollers 40. During the transport, the perovskite precursor is heated and crystallized on the substrate 1 by hot air from the nozzle 41 to become perovskite, and a perovskite film is formed. At this time, since the substrate 1 from which the solvent has been removed is transported, the evaporation of the solvent and the formation of the perovskite do not proceed simultaneously, resulting in a uniform crystal state, and defects (voids) that cause short circuits are unlikely to be formed. In addition, as described above, convection is unlikely to occur in the solution on the substrate 1, and further, the entire crystallization chamber 15 has a substantially uniform temperature, so that a perovskite film of uniform quality is formed on the entire substrate 1.

[0054] In the annealing chamber 16, the perovskite film laminate 3 in which the perovskite film is formed on the substrate 1 is wound around the winding shaft 50, and finally becomes a large roll. The perovskite film is heated from the time the perovskite film laminate 3 enters the annealing chamber 16 until the rolled perovskite film laminate 3 is removed from the annealing chamber 16. The stress in the perovskite film is relieved by the heating in the annealing chamber 16. Note that since the annealing chamber 16 has a lower temperature than the crystallization chamber 15, the perovskite film laminate 3 is not rapidly cooled when removed from the annealing chamber 16, and cracks are less likely to occur in the perovskite film.

[0055] The perovskite film laminate 3 taken out of the annealing chamber 16 is carried to another device, in which a hole transport layer and an electrode are laminated on the perovskite film in the perovskite film laminate 3 to form a perovskite solar cell.

[0056] (10) Effects The perovskite film forming apparatus 10 of this embodiment includes a solvent removal chamber 14, which is a zone in which the solvent is removed from the solution applied to the substrate 1 without crystallizing the perovskite precursor, and a crystallization chamber 15, which is a zone in which the perovskite precursor is crystallized on the substrate 1 after passing through the solvent removal chamber 14 to form a perovskite film. This makes it possible to prevent the removal of the solvent and the crystallization of the perovskite from proceeding simultaneously, and to form a high-quality perovskite film with a uniform crystal structure and few defects. In addition, since the perovskite film can be formed by passing the substrate 1 through the solvent removal chamber 14 and the crystallization chamber 15 in sequence, the perovskite film can be continuously manufactured and mass-produced.

[0057] As described above, the high quality of the perovskite film makes the perovskite solar cell more efficient at generating electricity and more durable. In addition, the high quality of the perovskite film can be formed, improving the yield rate during mass production. These factors are expected to lead to the widespread use of perovskite solar cells, reducing the use of fossil fuels for power generation and the associated carbon dioxide emissions.

[0058] In addition, the perovskite film forming apparatus 10 is provided with an unwinding section 11 that unwinds the substrate 1 before the solution is applied, and a winding section (annealing chamber 16) that winds up the perovskite film laminate 3 in which the perovskite film is formed on the substrate 1, and a coating chamber 13, a solvent removal chamber 14, and a crystallization chamber 15 are provided between the unwinding section 11 and the winding section. As a result, one long substrate 1 is unwound from the unwinding section 11 on one side, and wound up in the winding section on the other side. Then, during the transportation of the substrate 1 from the unwinding section 11 to the winding section as described above, the substrate 1 can be coated with the solution, the solvent can be removed from the solution, and the perovskite precursor can be crystallized. Therefore, the perovskite film laminate 3 can be mass-produced more efficiently.

[0059] Further, the solvent removal chamber 14 is provided with an infrared irradiator 31 that irradiates the solution with infrared rays of a wavelength that is absorbed by the solvent but not easily absorbed by the perovskite precursor, and the infrared irradiator 31 irradiates the solution with infrared rays. This allows the solvent to evaporate and the solution to be heated at a temperature at which the perovskite precursor does not crystallize, thereby removing the solvent. Therefore, the solvent can be removed from the solution without raising the temperature of the perovskite precursor to a temperature at which it crystallizes, and it is possible to prevent solvent removal and crystallization from proceeding simultaneously.

[0060] The solvent removal chamber 14 is provided with a transport roller 30 for transporting the substrate 1 on the transport roller 30 and a roller cooling device 33 for cooling the transport roller 30. The transport roller 30 is configured to transport the substrate 1 with the surface coated with the solution facing up. Therefore, by cooling the transport roller 30, the substrate 1 can be cooled from the lower surface side, and the temperature of the substrate 1 side in the solution layer 2 can be reduced. This prevents a temperature difference from occurring in the solution layer 2 and a convection current from occurring, even if the temperature of the surface (upper surface) of the solution layer 2 is reduced due to the evaporation of the solvent, and prevents the generation of Benard cells and the resulting cracks.

[0061] In addition, in the solvent removal chamber 14, a straightening device that sends air above the transport rollers 30 is provided, so that the air flow can be straightened above the solution layer 2 on the substrate 1, thereby preventing the formation of unevenness in the solution layer 2. Here, since the direction of the air sent by the straightening device is the same as the transport direction of the substrate 1, unevenness as wind ripples is unlikely to be formed in the solution layer 2.

[0062] In addition, a second pressure adjustment chamber 18 is provided between the solvent removal chamber 14 and the crystallization chamber 15, and the intake and exhaust in the second pressure adjustment chamber 18 are controlled to eliminate the difference in air pressure between the solvent removal chamber 14 and the crystallization chamber 15. Therefore, there is almost no difference in air pressure between the solvent removal chamber 14 and the crystallization chamber 15, air flow is unlikely to occur between the crystallization chamber 15 and the solvent removal chamber 14, and conditions such as temperature are maintained in each of the crystallization chamber 15 and the solvent removal chamber 14. For example, it is unlikely that a situation will occur in which high-temperature air from the crystallization chamber 15 flows into the solvent removal chamber 14, causing the solvent removal chamber 14 to become hot, and the perovskite precursor is crystallized in the solvent removal chamber 14.

[0063] In addition, pressure adjustment chambers 17, 19 are provided between the coating chamber 13 and the solvent removal chamber 14 and between the crystallization chamber 15 and the annealing chamber 16, so that air movement is less likely to occur between the coating chamber 13 and the solvent removal chamber 14 and between the crystallization chamber 15 and the annealing chamber 16, and the temperature, etc. of each zone is maintained at an appropriate value.

[0064] In the crystallization chamber 15, the substrate 1 transported by the transport rollers 40 is exposed to hot air to heat the substrate 1 to a temperature equal to or higher than the temperature at which the perovskite precursor crystallizes, thereby performing crystallization. Since the substrate 1 from which the solvent has been removed is transported to the crystallization chamber 15, evaporation of the solvent and formation of the perovskite do not proceed simultaneously, and when the perovskite precursor is crystallized by the hot air from the nozzle 41 to form a perovskite film, the crystallization is uniform, and defects (voids) that may cause short circuits are unlikely to form.

[0065] In addition, in the crystallization chamber 15, a plurality of nozzles 41 each having hot air outlets 41a, 41b are arranged in the front-rear direction, and an air inlet 42 is provided between adjacent nozzles 41, so that the hot air blown out from the outlets 41a, 41b is sucked into the inlet 42 and discharged in a comparatively short time. Therefore, the temperature rise caused by the hot air is localized, and the temperature of the hot air is unlikely to be transmitted to the solvent removal chamber 14. This makes it possible to prevent the perovskite precursor from crystallizing in the solvent removal chamber 14.

[0066] In addition, since the annealing chamber 16 is provided as an area where the base material 1 reaches after passing through the crystallization chamber 15, the stress of the crystallized perovskite can be relaxed. Here, since the perovskite film laminate 3 is wound up in the annealing chamber 16, the stress of the perovskite can be relaxed while the perovskite film laminate 3 is being wound up. In addition, since the temperature of the annealing chamber 16 is lower than the temperature of the crystallization chamber 15 and higher than room temperature, the perovskite film is not rapidly cooled when the perovskite film laminate 3 is moved from the crystallization chamber 15 to the annealing chamber 16 and when it is taken out from the annealing chamber 16, and cracks are unlikely to occur in the perovskite film.

[0067] Furthermore, by controlling the humidity in the annealing chamber 16 with a dehumidifier, deterioration of the perovskite film can be prevented.

[0068] Moreover, the method for forming a perovskite film of this embodiment includes a step of removing the solvent from the solution applied to the substrate 1 without crystallizing the perovskite precursor, and a step of crystallizing the perovskite precursor on the substrate 1 to form a perovskite film after the step of removing the solvent. This allows the removal of the solvent to be performed separately from the crystallization of the perovskite precursor into perovskite, and makes it possible to form a high-quality perovskite film with a uniform crystal structure and few defects.

[0069] (11) Example of changes The above disclosure is merely illustrative and various modifications may be made.

[0070] For example, a blower may be provided in the solvent removal chamber 14 to blow air at a temperature equal to or lower than that of the solvent removal chamber 14 (e.g., room temperature or a low temperature that does not cause condensation) toward the substrate 1, and the air from the blower may prevent the temperature of the perovskite precursor on the substrate 1 from increasing.

[0071] Furthermore, instead of indirectly cooling the substrate 1 by cooling the transport rollers 30 in the solvent removal chamber 14, the substrate 1 may be cooled in advance at a stage prior to the removal of the solvent in the solvent removal chamber 14.

[0072] Furthermore, the pressure adjustment chamber may be any chamber capable of reducing the pressure difference between the adjacent areas to the front and rear, and the specific configuration and control method may be different from those of the pressure adjustment chambers 17, 18, and 19 described above.

[0073] Also, a winding shaft 50 may be disposed ahead of the annealing chamber 16, and the substrate 1 after passing through the annealing chamber 16 may be wound up on the winding shaft 50. In this case, the location where the winding shaft 50 is disposed can be said to be the winding section.

[0074] Although one embodiment of the present invention has been described above, this embodiment is presented as an example and is not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are included in the scope of the invention and its equivalents described in the claims. [Explanation of symbols]

[0075] 1...substrate, 2...solution layer, 3...perovskite film laminate, 10...perovskite film forming apparatus, 11...unwinding section, 12...surface treatment section, 13...coating chamber, 14...solvent removal chamber, 15...crystallization chamber, 16...annealing chamber, 17...first pressure adjustment chamber, 18...second pressure adjustment chamber, 19...third pressure adjustment chamber, 20...winding shaft, 21...die, 22...backup roller, 23...air supply port, 23a...damper, 24...exhaust port, 24a...damper, 25a...air pressure sensor, 25b...air pressure sensor, 29...partition wall, 30...conveyor roller, 31...infrared irradiation device, 32a...air blower, 32b...air intake device, 33...roller cooling device, 40...conveyor roller, 41...nozzle, 41a...front outlet, 41b...rear outlet, 42...suction port, 43...exhaust chamber, 44...air supply chamber, 45...air supply path, 50...winding shaft, 51...air intake, 52...exhaust port, 60...control unit

Claims

1. A perovskite film forming apparatus for forming a perovskite film by crystallizing a solution containing a perovskite precursor and a solvent on a substrate, the perovskite precursor being applied thereto, the perovskite film being formed by: The area through which the continuously transported substrate passes is as follows: a solvent removal chamber, which is an area where the solution on the substrate is heated to a temperature where the solvent evaporates and the perovskite precursor does not crystallize, thereby removing the solvent from the solution applied to the substrate without crystallizing the perovskite precursor; a crystallization chamber, which is a region in which the perovskite precursor is crystallized by heating the perovskite precursor to a crystallization temperature or higher on the substrate from which the solvent has been removed after passing through the solvent removal chamber to form the perovskite film; was established, The solvent and the perovskite precursor absorb different wavelengths of infrared light, an infrared ray irradiation device is provided in the solvent removal chamber, which irradiates infrared rays having a specific wavelength that is absorbed by the solvent; the infrared irradiation device irradiates the solution with infrared light of the specific wavelength and heats the solution at a temperature at which the solvent evaporates and the perovskite precursor does not crystallize, thereby evaporating and removing the solvent without crystallizing the perovskite precursor; The solvent removal chamber is provided with a transport roller for transporting the base material thereon, the transport roller transports the base material with the surface on which the solution is applied facing up; A roller cooling device is provided to cool the conveying roller. Perovskite film formation equipment.

2. An unwinding section that unwinds the substrate before the solution is applied, an application chamber that applies the solution to the substrate, and a winding section that winds up the substrate on which the perovskite film is formed are further provided, The solvent removal chamber and the crystallization chamber are provided in this order as a section provided between the coating chamber and the winding section. The perovskite film forming apparatus according to claim 1 .

3. a conveying roller that conveys the base material to the solvent removal chamber with the base material placed thereon; A straightening device is provided above the conveying roller to send air in the same direction as the conveying direction of the base material. The perovskite film forming apparatus according to claim 1 or 2.

4. In the crystallization chamber, hot air is blown from a plurality of nozzles to heat the perovskite precursor from which the solvent has been removed to a crystallization temperature or higher, thereby crystallizing the perovskite precursor. The perovskite film forming apparatus according to claim 1 or 2.

5. In the crystallization chamber, a plurality of the nozzles each having a hot air outlet are arranged in a front-rear direction, An air suction port is provided between adjacent nozzles. The perovskite film forming apparatus according to claim 4.

6. a pressure adjustment chamber is provided between the solvent removal chamber and the crystallization chamber; The pressure adjustment chamber is controlled so that the difference between the air pressure in the solvent removal chamber and the air pressure in the crystallization chamber is eliminated by the intake and exhaust of air in the pressure adjustment chamber. The perovskite film forming apparatus according to claim 1 or 2.

7. an annealing chamber is provided as a zone where the substrate reaches after passing through the crystallization chamber; The temperature of the annealing chamber is lower than that of the crystallization chamber and higher than room temperature. The perovskite film forming apparatus according to claim 1 or 2.

8. A method for forming a perovskite film, comprising: applying a solution containing a perovskite precursor and a solvent to a substrate; and crystallizing the perovskite precursor on the substrate to form a perovskite film, the method comprising the steps of: heating the solution on the substrate to a temperature at which the solvent evaporates and the perovskite precursor does not crystallize, thereby removing the solvent from the solution applied to the substrate without crystallizing the perovskite precursor; After the step of removing the solvent, a step of crystallizing the perovskite precursor on the substrate from which the solvent has been removed by heating the perovskite precursor to a crystallization temperature or higher to form the perovskite film; Equipped with The solvent and the perovskite precursor absorb different wavelengths of infrared light, In the step of removing the solvent, an infrared irradiator irradiates the solution with infrared light having a specific wavelength that is absorbed by the solvent, thereby heating the solution, thereby evaporating and removing the solvent without crystallizing the perovskite precursor; the step of removing the solvent is performed while the substrate is being transported by transport rollers, and in the step of removing the solvent, the transport rollers transport the substrate with the surface on which the solution is applied facing up, and cool the substrate from the underside. Method for forming a perovskite film.

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