Inspection apparatus, molding apparatus, and inspection method for perovskite films

Abstract

To provide an inspection device that enables quick and appropriate inspection of the surface condition of a perovskite film formed on a substrate during the manufacturing process of a product. [Solution] In this embodiment, the perovskite film inspection apparatus comprises a light irradiation unit, an imaging unit, and an image processing unit. The light irradiation unit irradiates light onto a substrate on which the perovskite film is formed. The imaging unit captures an image of the light incident on the perovskite film while the substrate is being irradiated with light from the light irradiation unit. The image processing unit performs image analysis on the image captured by the imaging unit to determine at least the surface state of the perovskite film.

Description

Technical Field

[0001] Embodiments of the present invention relate to an inspection apparatus, a forming apparatus, and an inspection method for a perovskite film.

Background Art

[0002] In the manufacture of products, a perovskite film may be formed on a substrate. For example, in the manufacture of perovskite solar cells, a perovskite film serving as a light-emitting layer is formed on a substrate including a transparent electrode. Then, after the perovskite film is formed, an electrode plate having a polarity opposite to that of the transparent electrode is attached to the substrate on which the perovskite film is formed, and the perovskite film is sandwiched between the transparent electrode and the electrode plate, whereby the perovskite solar cell is manufactured as a product.

[0003] When forming a perovskite film on a substrate in the manufacture of a product as described above, defects such as unevenness and pinholes may occur on the surface of the perovskite film depending on the environment in which the raw material liquid is applied to the substrate and the environment in which the applied raw material liquid is dried. Since the surface state of the perovskite film affects the characteristics of the product, in the formation of the perovskite film, it is required to appropriately inspect the surface state of the formed perovskite film. Further, it is required that the inspection of the surface state of the perovskite film be performed in a short time at an intermediate stage of the manufacture before the final product is manufactured.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] The problem that this invention aims to solve is to provide an inspection apparatus and inspection method that enable the surface state of a perovskite film formed on a substrate to be appropriately inspected in a short time during the manufacturing process of a product. Furthermore, the invention aims to provide a perovskite film molding apparatus equipped with this inspection apparatus. [Means for solving the problem]

[0006] In this embodiment, the perovskite film inspection apparatus comprises a light irradiation unit, an imaging unit, and an image processing unit. The light irradiation unit irradiates light onto a substrate on which the perovskite film is formed. The imaging unit captures an image of the light incident on the perovskite film while the substrate is being irradiated with light from the light irradiation unit. The image processing unit performs image analysis on the image captured by the imaging unit to determine at least the surface state of the perovskite film. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 is a schematic diagram showing an example of a molding apparatus for forming a perovskite film on a substrate in the embodiment, etc. [Figure 2] Figure 2 is a schematic diagram showing an example of a configuration in which the perovskite film to be inspected is formed on a substrate in the embodiment. [Figure 3] Figure 3 is a schematic diagram showing an example of a situation in which the surface condition of a perovskite film formed on a substrate is inspected by an inspection device in the embodiment. [Figure 4] Figure 4 is a flowchart illustrating an example of the processing performed by the image processing unit in the inspection of the surface state of a perovskite film in the embodiment. [Figure 5] Figure 5 is a schematic diagram showing an example of a situation in which the thickness of a perovskite film formed on a substrate is inspected by an inspection device in the embodiment. [Figure 6] Figure 6 shows images of the perovskite films of four samples, obtained by scanning electron microscopy in the first verification related to the embodiment, etc. [Figure 7] Figure 7 is a schematic diagram showing the conversion efficiency as a perovskite solar cell and the L* value in the image captured from the front side, calculated for each of the four samples in the first verification related to the embodiment, etc. [Figure 8] Figure 8 is a schematic diagram showing the a* and b* values ​​in the rear-facing images, which were calculated for each of the six samples in the second verification related to the embodiment, etc. [Modes for carrying out the invention]

[0008] The embodiments will be described below with reference to the drawings.

[0009] (Embodiment) Figure 1 is a schematic diagram showing an example of a molding apparatus 1 for forming a perovskite film on a substrate in an embodiment. As shown in Figure 1, the molding apparatus 1 comprises a transport unit 2, a control unit (control device) 3, a coating unit 5, a drying unit 6, and two inspection devices (inspection units) 7 and 8. The transport unit 2 is composed of, for example, a belt conveyor and transports the substrate from the upstream side to the downstream side. In the molding apparatus 1, the coating unit 5, the drying unit 6, and the inspection device 7 are arranged in the transport unit 2 in this order from the upstream side to the downstream side.

[0010] The control unit 3 controls the overall operation of the molding apparatus 1, for example, controlling the transport operation in the transport unit 2. The control unit 3 also controls the operations of the coating unit 5, drying unit 6, and inspection devices 7 and 8, which will be described later. The control unit 3 includes a processor or integrated circuit (control circuit) including a CPU (Central Processing Unit), ASIC (Application Specific Integrated Circuit), or FPGA (Field Programmable Gate Array), and a storage medium such as memory. The control unit 3 may include only one integrated circuit or multiple integrated circuits. The control unit 3 performs processing by executing programs stored in the storage medium. The control by the control unit 3 may be performed by an integrated circuit in a single computer, or by integrated circuits in multiple computers working together. Furthermore, the control by the control unit 3 may be performed by a server in a cloud environment.

[0011] In the coating unit 5, the substrate is transported from the upstream side. The coating unit 5 then applies a raw material solution, in which the perovskite material is dissolved in a solvent, to the substrate. The method of applying the raw material solution to the substrate is not particularly limited, and the raw material solution is applied by an appropriate coating method. In one example, the raw material solution is applied to the substrate by meniscus coating or inkjet coating. In the drying unit 6, the substrate with the raw material solution applied is transported from the coating unit 5. The drying unit 6 dries the raw material solution applied to the substrate. In this case, for example, the drying unit 6 dries the raw material solution by blowing air and heating. By drying the raw material solution in the drying unit 6, a perovskite film is formed on the surface of the substrate.

[0012] Substrates with perovskite films formed on them are transported from the drying section 6 to the inspection device (first inspection device) 7. The inspection device 7 inspects the perovskite films formed on the substrates. The inspection device 7 determines whether the perovskite films are good or bad as an inspection result. If the inspection result in the inspection device 7 is good (OK), the substrates with perovskite films formed on them are transported downstream. Then, the next process in product manufacturing is carried out at the destination.

[0013] On the other hand, if the inspection result in inspection device 7 is poor (NG), the substrate on which the perovskite film is formed is transported to inspection device 8. At this time, the control unit 3 performs operational control, for example, with respect to the transport operation of the transport unit 2, preventing the substrate on which the perovskite film is formed from being transported downstream. Inspection device (second inspection device) 8 performs further inspection on the perovskite film that failed the inspection result in inspection device 7. At this time, inspection device 8 performs a more detailed inspection than the inspection in inspection device 7. The details of the inspections performed by inspection devices 7 and 8 will be described later.

[0014] Figure 2 is a schematic diagram showing an example of a configuration in which the perovskite film 11 to be inspected is formed on a substrate 12 in the embodiment. As shown in Figure 2, the substrate 12 on which the perovskite film 11 is formed has a defined thickness direction (directions indicated by arrows D1 and D2). The substrate 12 also has a front surface 15 and a back surface 16 as a pair of main surfaces. On the substrate 12, the front surface 15 faces one side in the thickness direction (arrow D1 side), and the back surface 16 faces the opposite side in the thickness direction from the side that the front surface 15 faces (arrow D2 side). On the substrate 12, the distance along the thickness direction between the front surface 15 and the back surface 16 corresponds to the thickness.

[0015] In the substrate 12, the side facing the front surface 15 is defined as the front side, and the side facing the back surface 16 is defined as the back side. The front surface 15 is also referred to as the "head surface," and the back surface 16 is also referred to as the "tail surface" or "rear surface." The front side is also referred to as the "front side" or "head surface side," and the back side is also referred to as the "back side," "rear side," or "rear side." Light can pass through the substrate 12, and the substrate 12 is formed to be transparent, for example. Therefore, in the substrate 12, light incident from the front surface 15 can pass through the substrate 12 and be emitted from the back surface 16, and light incident from the back surface 16 can pass through the substrate 12 and be emitted from the front surface 15.

[0016] In the molding apparatus 1, a perovskite film 11 is formed on the front surface 15 of the substrate 12. However, no perovskite film 11 is formed on the back surface 16 of the substrate 12. In other words, on the substrate 12, the perovskite film 11 is formed only on the front surface 15, which is one of a pair of main surfaces. Each of the inspection apparatuses 7 and 8 performs the inspection described later, targeting the perovskite film 11 formed on the front surface 15 of the substrate 12.

[0017] Here, an example of a product in which a perovskite film 11 is formed on a substrate 12 during the manufacturing process is a perovskite solar cell. A perovskite solar cell comprises a transparent electrode and an electrode plate with the opposite polarity to the transparent electrode as a pair of electrodes. A perovskite film, which serves as a power generation layer, is provided between the transparent electrode and the electrode plate. In a perovskite solar cell where the transparent electrode is the positive electrode, a hole transport layer is formed between the transparent electrode and the perovskite film, and an electron transport layer is formed between the electrode plate and the perovskite film. In a perovskite solar cell where the transparent electrode is the negative electrode, an electron transport layer is formed between the transparent electrode and the perovskite film, and a hole transport layer is formed between the electrode plate and the perovskite film.

[0018] In the manufacturing of perovskite solar cells, a perovskite film, which will serve as the power generation layer, is formed on a substrate containing transparent electrodes. At this time, in addition to the transparent electrodes, one of the corresponding hole transport layer and electron transport layer is formed on the substrate. If the inspection result from the inspection device 7 is good, an electrode plate with the opposite polarity to that of the transparent electrodes is attached to the substrate on which the perovskite film is formed, and the perovskite film is sandwiched between the transparent electrodes and the electrode plate. At this time, the one of the hole transport layer and electron transport layer that is not formed on the substrate is attached to the substrate in addition to the electrode plate.

[0019] In the embodiments, the inspection device (first inspection device) 7 performs at least an inspection of the surface condition of the perovskite film 11 formed on the substrate 12. In the inspection of the surface condition of the perovskite film 11, it is determined whether or not defects such as unevenness and pinholes occur on the surface of the perovskite film 11. In products using the perovskite film 11, if defects occur on the surface of the perovskite film 11, the product characteristics will be reduced compared to the normal case where there are no defects on the surface of the perovskite film 11. For example, in a perovskite solar cell using the perovskite film 11, if defects occur on the surface of the perovskite film 11, the conversion efficiency will be reduced compared to the normal case. The conversion efficiency of a perovskite solar cell corresponds to the rate at which energy from sunlight is converted into electrical energy.

[0020] Figure 3 is a schematic diagram showing an example of a situation in which the surface condition of a perovskite film 11 formed on a substrate 12 is inspected by an inspection device (first inspection device) 7 in an embodiment. As shown in Figure 3, the inspection device 7 comprises a light irradiation unit 21, an imaging unit 22, and an image processing unit 23. The light irradiation unit 21 is composed of, for example, a lighting fixture, and its illumination operation is controlled by the control unit 3. In the inspection of the surface condition of the perovskite film 11, the light irradiation unit 21 irradiates light onto the substrate 12 on which the perovskite film 11 is formed (arrow A1). At this time, the light irradiation unit 21 irradiates light from the front side of the substrate 12 toward the perovskite film 11.

[0021] The imaging unit 22 is, for example, a line scan camera, which images the subject by scanning it. The imaging unit 22 can scan the subject at a relatively high speed and can image a wider area than a scanning electron microscope, etc. In one example, the line scan camera that becomes the imaging unit 22 can image the subject with a scan width of 1 mm or more. The imaging operation by the imaging unit 22 is controlled by the control unit 3, etc. In the inspection of the surface state of the perovskite film 11, the imaging unit 22 captures an image of the light incident from the perovskite film 11 to the imaging unit 22 when light is irradiated onto the substrate 12 from the light irradiation unit 21 (arrow A2). As a result, an image of the perovskite film 11 as the subject is captured by the imaging unit 22.

[0022] In this case, the imaging unit 22 captures an image (the first image) from the front side of the substrate 12. When the imaging unit 22 is capturing an image from the front side of the substrate 12, the light that is irradiated from the light irradiation unit 21 and then reflected by the perovskite film 11 is included in the light incident from the perovskite film 11 to the imaging unit 22. When the surface condition of the perovskite film 11 is being inspected in the same manner as in the example in Figure 3, the light that is irradiated from the light irradiation unit 21 and then reflected by the perovskite film 11 accounts for the majority of the light incident from the perovskite film 11 to the imaging unit 22.

[0023] The image processing unit 23 is composed of, for example, an image processor. In the inspection of the surface state of the perovskite film 11, the image processing unit 23 acquires an image (first image) of the perovskite film 11 taken from the front side of the substrate 12 from the imaging unit 22. The image processing unit 23 then performs image analysis on the acquired image and makes a determination regarding the surface state of the perovskite film 11 based on the analysis results. At this time, the image processing unit 23 calculates image features in the acquired image and makes a determination regarding the surface state of the perovskite film 11 based on the calculation results of the image features.

[0024] Figure 4 is a flowchart illustrating an example of processing performed by the image processing unit 23 in an inspection of the surface state of the perovskite film 11 in the embodiment. The processing in the example shown in Figure 4 is performed by the image processing unit 23 each time an inspection of the surface state of the perovskite film 11 is performed on a single inspection target. When the processing in the example shown in Figure 4 is started, the image processing unit 23 divides the captured image (first image) into multiple regions (S101). The image processing unit 23 then calculates image features for each of the divided regions (S102). At this time, the image processing unit 23 calculates image features for each pixel that makes up the captured image, for example. The image processing unit 23 then calculates the average value of the image features of the pixels included in each of the divided regions as the calculated image features for that region.

[0025] In the example processing shown in Figure 4, a reference range is set for the image features to be calculated, and the image processing unit 23 compares the calculated image features for each of the divided regions with the reference range. The image processing unit 23 then determines whether there are any regions in the captured image where the image features do not fall within the reference range (S103). If the image features fall within the reference range in any of the multiple regions, that is, if there are no regions where the image features do not fall within the reference range (S103-No), the image processing unit 23 determines that there are no defects on the surface of the perovskite film 11 and determines that the surface condition of the perovskite film 11 is good (S104).

[0026] On the other hand, if the image feature amount does not fall within the reference range in any one or more of the plurality of regions, that is, if there is a region where the image feature amount does not fall within the reference range (S103-Yes), the image processing unit 23 determines that there is a defect on the surface of the perovskite film 11 and determines that the surface state of the perovskite film 11 is defective (S105). At this time, in each region where the image feature amount does not fall within the reference range, it is determined that any of unevenness and pinholes has occurred on the surface of the perovskite film 11. Then, the image processing unit 23 specifies the position information of the region where the image feature amount does not fall within the reference range (S106).

[0027] Also, in an example of FIG. 4, the image processing unit 23 can communicate with the control unit 3 by wire or wirelessly. When there is a region where the image feature amount does not fall within the reference range, the image processing unit 23 transmits a signal indicating that to the control unit 3. Then, the control unit 3 controls the operation of the transport unit 2 so that the substrate 12 on which the perovskite film 11 to be inspected is formed is not transported to the next process in response to receiving the signal from the image processing unit 23. That is, the image processing unit 23 causes the control unit 3 to execute an operation control not to transport the substrate 12 on which the perovskite film 11 is formed to the downstream side (S107).

[0028] As the image feature amount in the captured image, the image processing unit 23 calculates, for example, any one or more of the L * a * b * values in the color space of L * value, a * value, and b * value. In one example, the image processing unit 23 calculates the L * value as the image feature amount for each of the plurality of regions divided in the captured image. Then, for a region where the L * value is less than or equal to the reference value, the image processing unit 23 determines that the L * value falls within the reference range, and for a region where the L * value is greater than the reference value, the image processing unit 23 determines that the L * value does not fall within the reference range. Therefore, the L *If there is a region where the value is greater than the reference value, it is determined that a defect has occurred on the surface of the perovskite film 11, and the surface condition of the perovskite film 11 is determined to be poor.

[0029] Here, when defects such as unevenness and pinholes occur on the surface of the perovskite film 11, the perovskite film 11 tends to appear cloudy compared to a normal perovskite film 11 where no defects occur on the surface. Therefore, when the perovskite film 11 is imaged from the front side of the substrate 12, the image of the perovskite film 11 with defects on its surface appears cloudy compared to the image of a normal perovskite film 11. * The value tends to be large. Therefore, in the image of the perovskite film 11 captured from the front side of the substrate 12, L * By determining whether the value is below the reference value, it becomes possible to appropriately determine whether or not a defect has occurred on the surface of the perovskite film 11. That is, the L value in the image of the perovskite film 11 * Based on the values, it becomes possible to appropriately determine the quality of the surface condition of the perovskite film 11.

[0030] In a preferred embodiment, the inspection device (first inspection device) 7 performs an inspection of the perovskite film 11 formed on the substrate 12, in addition to the inspection of the surface condition described above. The inspection of the film thickness of the perovskite film 11 is performed, for example, only if the surface condition of the perovskite film 11 is determined to be good. If the surface condition of the perovskite film 11 is determined to be poor, the inspection device 7 determines that the perovskite film 11 is poor without performing an inspection of the film thickness of the perovskite film 11.

[0031] In products using the perovskite film 11, variations in the film thickness of the perovskite film 11 between products affect the product characteristics. In this example, the inspection of the film thickness of the perovskite film 11 is performed by checking whether the perovskite film 11 is formed with a film thickness that falls within the reference film thickness range, thereby suppressing variations in the film thickness of the perovskite film 11 between products. This suppresses variations in product characteristics between products.

[0032] Figure 5 is a schematic diagram showing an example of a situation in which an inspection of the film thickness of the perovskite film 11 formed on the substrate 12 is performed by an inspection device (first inspection device) 7 in the embodiment, etc. As shown in Figure 5, in the inspection of the film thickness of the perovskite film 11, similar to the inspection of the surface condition, the light irradiation unit 21 irradiates light onto the substrate 12 on which the perovskite film 11 is formed (arrow A3). However, in the inspection of film thickness, the light irradiation unit 21 irradiates light from the back side of the substrate 12 toward the perovskite film 11.

[0033] For inspections related to film thickness, the same light irradiation unit 21 used for surface condition inspections may be used, or a different light irradiation unit 21 may be used for surface condition inspections. In one example, the same light irradiation unit 21 used for surface condition inspections is used for film thickness inspections, and in film thickness inspections, the light irradiation unit 21 is moved from the position where light was irradiated in surface condition inspections. Then, in film thickness inspections, the light irradiation unit 21 irradiates light from the newly moved position.

[0034] Furthermore, in the inspection of the film thickness of the perovskite film 11, similar to the inspection of the surface condition, the imaging unit 22 captures an image of the light incident from the perovskite film 11 to the imaging unit 22 while light is being irradiated onto the substrate 12 from the light irradiation unit 21 (arrow A4). Then, an image with the perovskite film 11 as the subject is captured by the imaging unit 22. However, in the inspection of film thickness, the imaging unit 22 captures the image (second image) from the back side of the substrate 12.

[0035] For inspections related to film thickness, the same imaging unit 22 used for surface condition inspections may be used, or a different imaging unit 22 may be used for surface condition inspections. In one example, the same imaging unit 22 used for surface condition inspections is used for film thickness inspections, and for film thickness inspections, the imaging unit 22 is moved from the position where imaging was performed for surface condition inspections. Then, for film thickness inspections, the imaging unit 22 performs imaging at the moved position.

[0036] As mentioned above, light is transmissive to the substrate 12. Therefore, in the inspection of film thickness, light irradiated from the back side of the substrate 12 by the light irradiation unit 21 passes through the substrate 12 and is reflected by the perovskite film 11. The light reflected by the perovskite film 11 then passes through the substrate 12 and is emitted to the back side of the substrate 12. Consequently, when the imaging unit 22 is taking images from the back side of the substrate 12, the light that has been irradiated from the light irradiation unit 21 and reflected to the back side of the substrate 12 by the perovskite film 11 is included in the light incident from the perovskite film 11 to the imaging unit 22. And, in the same manner as in the example in Figure 5, when the inspection of the film thickness of the perovskite film 11 is being performed, the light that has been irradiated from the light irradiation unit 21 and reflected to the back side of the perovskite film 11 accounts for the majority of the light incident from the perovskite film 11 to the imaging unit 22.

[0037] In the inspection of the film thickness of the perovskite film 11, the image processing unit 23 acquires an image (second image) of the perovskite film 11 from the back side of the substrate 12 from the imaging unit 22. The image processing unit 23 then performs image analysis on the acquired image and makes a determination regarding the film thickness of the perovskite film 11 based on the results of the image analysis. At this time, similar to the inspection of the surface condition, the image processing unit 23 calculates image features in the acquired image and makes a determination regarding the film thickness of the perovskite film 11 based on the results of the image feature calculation.

[0038] In one example, the image processing unit 23 divides the captured image (second captured image) taken from the back side into multiple regions and calculates image features for each of the multiple regions. The image processing unit 23 then determines that the film thickness of the perovskite film 11 is good if there are no regions in the captured image where the image features do not fall within the reference range. On the other hand, if there are regions where the image features do not fall within the reference range, the image processing unit 23 determines that the film thickness of the perovskite film 11 is poor. If the image processing unit 23 determines that the film thickness of the perovskite film 11 is poor, it identifies the location information of the region where the image features do not fall within the reference range. The image processing unit 23 then instructs the control unit 3 to execute an operation control that prevents the substrate 12 on which the perovskite film 11 is formed from being transported downstream.

[0039] In inspections related to film thickness, the image processing unit 23 uses L as an image feature in the captured image. * a * b * L in color space * value, a * Value and b * One or more of the values ​​are calculated. In one example, the image processing unit 23 calculates a for each of the multiple regions divided in the image captured from the back side of the substrate 12 as an image feature quantity. * Value and b * Each of the values ​​is calculated. Then, the image processing unit 23 calculates a for each of the multiple regions. * Value and b * Determine whether each value falls within the reference range. Then, a * Value and b * If any of the values ​​are outside the reference range in any region, the thickness of the perovskite film 11 is determined to be poor. Therefore, if all of the divided regions are outside the reference range, * Value and b * Based on the fact that both values ​​fall within the reference range, the thickness of the perovskite film 11 is determined to be good.

[0040] Here, assuming that other conditions, including the surface state of the perovskite film 11, are the same, then in response to the change in the thickness of the perovskite film 11, the a in the image of the perovskite film 11 is... * Value and b * Each of the values ​​tends to change. Therefore, in the image of the perovskite film 11 captured from the back side of the substrate 12, a * Value and b * Based on the values, it becomes possible to appropriately determine the quality of the film thickness of the perovskite film 11.

[0041] As described above, if the inspection performed by the inspection device 7 determines that the surface condition of the perovskite film 11 is poor, the substrate 12 on which the perovskite film 11 is formed is not transported to the next process, but is instead transported to the inspection device 8. Also, in the example where the inspection of the film thickness of the perovskite film 11 is performed by the inspection device 7, even if the surface condition of the perovskite film 11 is determined to be good, if the film thickness of the perovskite film 11 is determined to be poor, the substrate 12 on which the perovskite film 11 is formed is not transported to the next process, but is instead transported to the inspection device 8.

[0042] In one example, the inspection device 8 includes a scanning electron microscope and an image processing unit such as an image processor. The image processing unit acquires location information of areas in the perovskite film 11 to be inspected where defects such as surface defects and film thickness defects occur. At this time, the image processing unit of the inspection device 8 acquires location information of the defective areas based on the location information of areas where the image feature quantities identified by the image processing unit 23 of the inspection device 7 do not fall within the reference range.

[0043] The image processing unit then acquires an image of the area where the defect occurs using a scanning electron microscope. In this process, the scanning electron microscope scans the area corresponding to the location information of the area where the defect occurs, thereby acquiring a scanning electron microscope image (SEM image). In the scanning electron microscope image, a narrower range is shown in magnification compared to the image captured by the imaging unit 22 of the inspection device 7. For example, in the scanning electron microscope image, only the area where the image features in the image captured by the imaging unit 22 do not fall within the reference range is shown in magnification.

[0044] In the inspection device 8, the image processing unit estimates and investigates the cause of defects in the perovskite film 11 by performing image analysis on images obtained with a scanning electron microscope. In this process, for example, an image of a perovskite film without defects is used as a reference image, and the cause of the defects is estimated based on the difference between the image obtained with the scanning electron microscope and the reference image.

[0045] As described above, in the embodiment, when light is irradiated onto the substrate 12 from the light irradiation unit 21, the imaging unit 22 captures an image of the light incident on the perovskite film 11 formed on the front surface 15 of the substrate 12. The image processing unit 23 then performs image analysis on the image captured by the imaging unit 22 to determine at least the surface state of the perovskite film 11. This allows for L in the captured image. * value, a * Value and b * By using one of the values ​​as an image feature, it becomes possible to appropriately determine whether or not defects such as unevenness and pinholes have occurred on the surface of the perovskite film 11. Therefore, the surface condition of the formed perovskite film 11 can be appropriately inspected.

[0046] As described above, by properly inspecting the surface condition of the perovskite film 11, the characteristics of the product are appropriately ensured in products using the perovskite film 11 that has been judged as good (OK) in the inspection. For example, in a perovskite solar cell that uses a perovskite film 11 that has been judged as good in the inspection device 7 as the power generation layer, the conversion efficiency is appropriately ensured without any decrease.

[0047] Furthermore, the inspection of the perovskite film 11 described above can be performed at an intermediate stage of manufacturing before the final product is manufactured. For example, in the manufacture of a perovskite solar cell using the perovskite film 11, after the perovskite film 11 has been formed on a substrate including transparent electrodes, it is possible to inspect the surface condition of the perovskite film 11 before attaching electrode plates or the like to the substrate. Therefore, the perovskite film 11 can be inspected without disassembling the final product. Consequently, the effort and cost involved in inspecting the perovskite film 11 can be reduced.

[0048] Furthermore, as described above, since the inspection is performed in this manner, the image of the perovskite film 11 that is image-analyzed during the inspection can be captured using a line scan camera or the like as the imaging unit 22. Therefore, the surface condition of the perovskite film 11 is inspected using an image that captures a relatively wide area. Since the surface condition of the perovskite film 11 can be determined over a relatively wide area by image analysis of a single image, the time required for inspecting the perovskite film 11 can be shortened. In other words, the surface condition of the perovskite film 11 can be inspected in a short amount of time.

[0049] Furthermore, in a preferred example of the embodiment, the image processing unit 23 analyzes the image captured by the imaging unit 22 to determine not only the surface state of the perovskite film 11 but also the film thickness of the perovskite film 11. This improves the accuracy of inspection of the perovskite film 11. By performing an inspection of the film thickness of the perovskite film 11, it becomes possible to determine whether or not the perovskite film 11 is formed with a film thickness that falls within the reference film thickness range. This suppresses variations in the film thickness of the perovskite film 11 between products, and thus suppresses variations in product characteristics between products.

[0050] Furthermore, in an example where both the surface condition and film thickness of the perovskite film 11 are inspected, the imaging unit 22 images the perovskite film 11 from the front side of the substrate 12 and also images the perovskite film 11 from the back side of the substrate 12. The image processing unit 23 then performs image analysis on the image captured from the front side (first image) to determine the surface condition of the perovskite film 11, and performs image analysis on the image captured from the back side (second image) to determine the film thickness of the perovskite film 11.

[0051] Based on the image features of the image captured from the front side of the substrate 12, a determination is made regarding the surface state of the perovskite film 11, thereby more accurately determining whether or not defects have occurred on the surface of the perovskite film 11. In particular, perovskite films 11 with surface defects tend to become cloudy. Therefore, L in the image captured from the front side of the substrate 12 * By using the values ​​as image features, the quality of the surface condition of the perovskite film 11 can be determined more appropriately.

[0052] Furthermore, in the embodiments, the substrate 12 on which the perovskite film 11 is formed is transparent to light. Therefore, it is possible to capture an image of the perovskite film 11 even from the back side of the substrate 12. In addition, by using the image captured from the back side of the substrate 12, the influence of clouding caused by defects on the surface of the perovskite film 11 is excluded, and image analysis of the captured image is performed. Therefore, the thickness of the perovskite film 11 can be determined more appropriately.

[0053] Furthermore, when the thickness of the perovskite film 11 changes, the a in the image of the perovskite film 11 changes. * Value and b * Each of the values ​​tends to change. Therefore, in the image taken from the wavefront side of the substrate 12, a * Value and b * By using one of the values ​​as an image feature, the quality of the film thickness of the perovskite film 11 can be determined more appropriately. In particular, a in the acquired image * Value and b * By using one of the values ​​as an image feature, it becomes possible to appropriately determine whether or not there is variation in film thickness between products.

[0054] (Verification related to the embodiment, etc.) Here, as verifications related to the embodiments, the first and second verifications described below were performed. In the first verification, four samples α1 to α4 were used. Each of the samples α1 to α4 was a perovskite solar cell in which a perovskite film is formed as the power generation layer. In this verification, images of the perovskite film (SEM images) were obtained for each of the samples α1 to α4 using a scanning electron microscope. Figure 6 shows the images of the perovskite films of the four samples α1 to α4 obtained by scanning electron microscopy in the first verification related to the embodiments.

[0055] As shown in Figure 6, samples α1 and α2 showed little to no defects on the surface of the perovskite film, such as unevenness and pinholes. Sample α3 showed some degree of defects on the surface of the perovskite film, with a higher degree of defects compared to samples α1 and α2. Sample α4 showed an even higher degree of defects on the surface of the perovskite film compared to sample α3.

[0056] In this verification, the conversion efficiency of each of the four samples α1 to α4 was measured as a perovskite solar cell. The conversion efficiencies for samples α1, α2, α3, and α4 were 13.6%, 13.3%, 5.1%, and 0%, respectively. Specifically, sample α3 had a lower conversion efficiency than samples α1 and α2, and sample α4 had a lower conversion efficiency than sample α3. This demonstrates that product characteristics such as conversion efficiency deteriorate in response to defects on the surface of the perovskite film.

[0057] Furthermore, in this verification, for each of the four samples α1 to α4, images of the perovskite film were captured from the front side of the substrate in the same manner as the example in Figure 3. Then, for each of the samples α1 to α4, the images captured from the front side of the substrate were analyzed, and the L of the images captured from the front side was determined. * The values ​​were calculated. Figure 7 shows the conversion efficiency as a perovskite solar cell and the L value in the image taken from the front side, calculated for each of the four samples α1 to α4 in the first verification related to the embodiment, etc. * This is a schematic diagram showing the values. Figure 7 shows a graph, in which the horizontal axis of the graph in Figure 7 shows the conversion efficiency in percentage, and the vertical axis shows L * a * b * L in color space * Show the value.

[0058] As shown in Figure 7, etc., sample α3 showed L in the captured image compared to samples α1 and α2, respectively.* The value increased, and in sample α4, compared to sample α3, the L in the captured image was larger. * The value increased. As a result, a defect occurred on the surface of the perovskite film, causing the perovskite film to become cloudy, and the L value in the image of the perovskite film taken from the front side of the substrate was increased. * It was demonstrated that the value becomes larger. From the first verification above, L in the image of the perovskite film captured from the front side of the substrate * It was demonstrated that the quality of the surface condition of the perovskite film can be appropriately determined based on the values.

[0059] Next, in the second verification, six samples β1 to β6 were used. For each of the six samples β1 to β6, a perovskite film was formed on the front surface of a light-transmitting substrate. However, the thickness of the perovskite film was varied among the six samples β1 to β6. In this verification, the samples were numbered β1, β2, β3, β4, β5, and β6 in order from thinnest to thickest film, and the perovskite film thicknesses for samples β1, β2, β3, β4, β5, and β6 were set to 252 nm, 356 nm, 503 nm, 636 nm, 755 nm, and 830 nm, respectively.

[0060] Furthermore, in this verification, for each of the six samples β1 to β6, images of the perovskite film were captured from the back side of the substrate in the same manner as the example in Figure 5. Then, for each of the samples β1 to β6, the images captured from the back side of the substrate were analyzed, and a * Value and b * The values ​​were calculated. Figure 8 shows the values ​​calculated for each of the six samples β1 to β6 in the second verification related to the embodiment, etc., in the rear view image. * Value and b * This is a schematic diagram showing the values. Figure 8 shows a graph, in which the horizontal axis represents the thickness of the perovskite film in nm, and the vertical axis represents L * a * b * a in color space * Value and b * The values ​​are shown. Also, in the graph of Figure 8, a against film thickness* The change in value is shown by the circle plot and the solid line, and b relative to the film thickness. * Changes in values ​​are shown by square plots and dashed lines.

[0061] As shown in Figure 8, etc., the a in the image taken from the back side corresponds to the change in the thickness of the perovskite film. * Value and b * Each of the values ​​changed. In this verification, the thicker the perovskite film, the greater the a in the acquired image. * Value and b * Each of the values ​​became smaller. From the second verification above, the a of the image of the perovskite film taken from the back side of the substrate * Value and b * It was demonstrated that the quality of the perovskite film thickness can be appropriately determined based on the values.

[0062] According to at least one embodiment or example, when the substrate is irradiated with light, an image is captured by the imaging unit of the light incident on the perovskite film formed on the substrate. Then, by performing image analysis on the image captured by the imaging unit, at least the surface state of the perovskite film is determined. This makes it possible to provide an inspection apparatus and inspection method that allows for the appropriate inspection of the surface state of the perovskite film formed on the substrate in a short time during the manufacturing process of the product.

[0063] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Explanation of Symbols]

[0064] 1... Molding apparatus, 2... Transport unit, 3... Control unit, 5... Coating unit, 7... Inspection apparatus (first inspection apparatus), 11... Perovskite film, 12... Substrate, 15... Front, 16... Back, 21... Light irradiation unit, 22... Imaging unit, 23... Image processing unit.

Claims

1. A light irradiation unit that irradiates light onto a substrate on which a perovskite film is formed, In a state in which the light is irradiated onto the substrate from the light irradiation unit, an imaging unit captures an image of the light incident on the perovskite film, An image processing unit that performs image analysis on the captured image captured by the imaging unit to determine at least the surface state of the perovskite film, An inspection device for perovskite membranes, comprising the following:

2. The light irradiation unit irradiates the substrate, on which the perovskite film is formed on the front surface and which is transparent to light, with the light. The imaging unit captures a first image from the front side of the substrate as the captured image, and captures a second image from the back side of the substrate as the captured image. The image processing unit performs image analysis on the first captured image to determine the surface state of the perovskite film, and performs image analysis on the second captured image to determine the film thickness of the perovskite film. The inspection apparatus according to claim 1.

3. The inspection apparatus according to claim 1, wherein the image processing unit determines the surface state of the perovskite film based on the image features in the captured image.

4. The inspection apparatus according to claim 3, wherein the image processing unit identifies the location information of a region in the captured image in which the image features do not fall within the reference range, when such a region exists in the captured image.

5. The inspection apparatus according to claim 3, wherein the image processing unit causes the control unit to perform operation control such that the substrate on which the perovskite film is formed is not transported downstream when there is a region in the captured image in which the image feature quantities do not fall within a reference range.

6. An inspection apparatus according to any one of claims 1 to 5, Upstream from the inspection apparatus, there is a coating section that applies the raw material liquid to the substrate to form the perovskite film on the substrate, A perovskite film molding apparatus comprising the following:

7. Irradiating a substrate on which a perovskite film has been formed with light, With the substrate being irradiated with the light, an image of the light incident on the perovskite film is captured by the imaging unit. By performing image analysis on the captured images obtained by the imaging unit, at least the surface state of the perovskite film can be determined. A method for inspecting perovskite membranes, comprising the following:

Images