JP5978339B1 - Coating apparatus, coating method, and coating program - Google Patents

Abstract

A coating apparatus, a coating method, and a coating program capable of uniformly coating an object to be coated having various planar shapes are provided. A coating apparatus including a stage, a coating head, and a control unit is provided. The stage 10 includes an upper surface 10u. The coating head 20 rotates about a first axis 20r that is substantially parallel to the upper surface 10u. The width of the coating head 20 in the direction of the first axis 20r varies along a circumferential direction D2 centered on the first axis 20r. The controller 30 performs an operation of causing at least one of the coating head 20 and the stage 10 to move relative to each other within a first surface substantially parallel to the upper surface 10u. [Selection] Figure 1

Description

  Embodiments described herein relate generally to a coating apparatus, a coating method, and a coating program.

  There is a solar cell including an organic semiconductor using a conductive polymer or fullerene. In this solar cell, a photoelectric conversion film can be formed on an object to be coated by a simple method using a coating apparatus. In the coating apparatus, it is required to be able to be applied to a coating object having various planar shapes.

JP 2012-153097 A

  Embodiments of the present invention provide a coating apparatus, a coating method, and a coating program that can be applied to a coating object having various planar shapes.

According to the embodiment of the present invention, a coating apparatus including a stage, a coating head, and a control unit is provided. The stage includes an upper surface. The coating head rotates about a first axis that is substantially parallel to the top surface. The width of the coating head in the first axis direction varies along a circumferential direction centered on the first axis. The control unit performs an operation of causing at least one of the coating head and the stage to move relatively parallel to the upper surface.
According to another embodiment of the present invention, there is provided an application head that is placed on the upper surface of a stage, and an application head that rotates about a first axis that is substantially parallel to the upper surface. Supplying a coating liquid between the coating head and a coating head having a width in one axial direction that changes along a circumferential direction centering on the first axis; and rotating the coating head, And a step of causing at least one of the stages to move relative to and substantially parallel to the upper surface.

FIG. 1A to FIG. 1C are schematic views illustrating a coating apparatus according to the first embodiment. FIG. 2A to FIG. 2D are schematic perspective views in order of the processes, illustrating the operation of the coating apparatus according to the first embodiment. It is a flowchart figure which illustrates the coating method which concerns on 1st Embodiment. It is a typical sectional view which illustrates a part of solar cell module concerning a 1st embodiment. It is a typical sectional view which illustrates another solar cell module concerning a 1st embodiment. FIG. 6A to FIG. 6C are schematic plan views in order of the processes, illustrating the method for manufacturing the solar cell module according to the first embodiment. FIG. 7A to FIG. 7D are schematic perspective views in order of the processes, illustrating the operation of the coating apparatus according to the second embodiment. FIG. 8A to FIG. 8C are schematic plan views in order of the processes, illustrating the method for manufacturing the solar cell module according to the second embodiment. FIG. 9A and FIG. 9B are schematic perspective views illustrating the operation of the coating apparatus according to the third embodiment. FIG. 6 is a schematic plan view illustrating a solar cell module according to a third embodiment.

Embodiments of the present invention will be described below with reference to the drawings.
The drawings are schematic or conceptual, and the relationship between the thickness and width of each part, the size ratio between the parts, and the like are not necessarily the same as actual ones. Further, even when the same part is represented, the dimensions and ratios may be represented differently depending on the drawings.
Note that, in the present specification and each drawing, the same elements as those described above with reference to the previous drawings are denoted by the same reference numerals, and detailed description thereof is omitted as appropriate.

(First embodiment)
FIG. 1A to FIG. 1C are schematic views illustrating a coating apparatus according to the first embodiment. FIG. 1A is a schematic plan view illustrating a coating apparatus. FIG. 1B is a schematic side view illustrating the coating apparatus viewed from the AA direction in FIG. FIG. 1C is a schematic perspective view illustrating a coating head.

  The coating apparatus 110 according to the present embodiment includes a stage 10, a coating head 20, a control unit 30, and a coating liquid supply unit 40.

  The stage 10 is a support table on which the application target object 50 is placed. Stage 10 includes an upper surface 10u. The upper surface 10u is along the X-axis direction and the Y-axis direction and is perpendicular to the Z-axis direction. The stage 10 has a circular shape, for example. The shape of the stage 10 is not particularly limited.

  The coating head 20 can rotate along the rotation direction D1 about the first shaft 20r. The direction of the rotation direction D1 may be changed. The first axis 20r is substantially parallel to the upper surface 10u. The first axis 20r may be substantially parallel to the upper surface 10u. The angle between the first axis 20r and the upper surface 10u is preferably in the range of ± 10 degrees, for example. The width wt in the direction of the first axis 20r of the coating head 20 varies along the circumferential direction D2 with the first axis 20r as the center. For example, the first axis 20r is along the Y-axis direction.

  The coating head 20 includes a first region 21 and a second region 22. The second region 22 is different from the first region 21 in the position in the circumferential direction D2. The width wt in the first region 21 includes the first width wt1. The width wt in the second region 22 includes the second width wt2. The first width wt1 is wider than the second width wt2. The first width wt1 is, for example, the maximum width of the coating head 20. The second width wt2 is, for example, the minimum width of the coating head 20. The width wt changes continuously. That is, the width wt in the first region 21 includes the maximum width of the coating head 20. The width wt in the second region 22 includes the minimum width of the coating head 20.

  A cross section when a part of the coating head 20 is cut in a direction orthogonal to the first axis 20r is, for example, a circular shape. This cross section may be elliptical. This cross section may be polygonal. The part of the coating head 20 is, for example, a central part of the coating head 20.

  The control unit 30 performs an operation of causing at least one of the coating head 20 and the stage 10 to relatively move within a first surface that is substantially parallel to the upper surface 10u. The first surface may be substantially parallel to the upper surface 10u. The angle between the first surface and the upper surface 10u is preferably in the range of ± 10 degrees, for example. In this example, relative movement is performed along the first direction X1 in the first plane. The first direction X1 is, for example, along the X-axis direction. The position of the stage 10 is fixed and the coating head 20 is moved. The position of the coating head 20 may be fixed and the stage 10 may be moved. The operation of the coating head 20 is controlled by the control unit 30. The operation of the stage 10 is controlled by the control unit 30.

  The application object 50 is placed on the upper surface 10 u of the stage 10. The application target 50 is, for example, a circular substrate used for a solar cell module described later. For example, the application head 20 faces the application object 50 in a non-contact state.

  The coating liquid supply unit 40 supplies the coating liquid 60 between the coating head 20 and the coating target object 50. The operation of the coating liquid supply unit 40 is controlled by the control unit 30.

  The control unit 30 rotates at least one of the coating head 20 and the stage 10 along the first direction X1 while rotating the coating head 20 in a state where the coating liquid 60 is supplied between the coating head 20 and the coating object 50. An operation of moving the relative position is performed. When the first direction X1 is a direction from the outside of the application target object 50 toward the center, the width of the coating liquid 60 held between the application head 20 and the application target object 50 is continuous toward the first direction X1. Narrow. Further, when the first direction X1 is a direction from the center of the application object 50 toward the outside, the width of the application liquid 60 held between the application head 20 and the application object 50 is directed toward the first direction X1. Widen continuously.

  For the control unit 30, for example, an arithmetic device including a CPU (Central Processing Unit), a memory, and the like is used. An integrated circuit such as LSI (Large Scale Integration) or an IC (Integrated Circuit) chip set can be used for a part or all of each block of the control unit 30. An individual circuit may be used for each block, or a circuit in which part or all of the blocks are integrated may be used. Each block may be provided integrally, or a part of the blocks may be provided separately. In addition, a part of each block may be provided separately. The integration is not limited to LSI, and a dedicated circuit or a general-purpose processor may be used.

  The control unit 30 controls the application operation by the application apparatus 110. The control unit 30 is realized as a coating program, for example. That is, the control unit 30 can also be realized by using a general-purpose computer device as basic hardware. The functions of the respective units included in the control unit 30 can be realized by causing a processor installed in the computer device to execute a coating program. At this time, the control unit 30 may be realized by installing the above application program in a computer device in advance, or may be stored in a storage medium such as a CD-ROM or the application program via a network. You may implement | achieve by distributing and installing this application | coating program in a computer apparatus suitably. Further, the control unit 30 is realized by appropriately using a memory, a hard disk, or a storage medium such as a CD-R, a CD-RW, a DVD-RAM, a DVD-R, or the like that is built in or externally attached to the computer device. Can do.

  The coating device 110 is used for manufacturing a solar cell module, for example. The coating apparatus 110 applies the material for the power generation layer (coating liquid 60) on the substrate (application object 50) of the solar cell module. The power generation layer is, for example, one of a first charge transport layer, a photoactive layer, and a second charge transport layer described later. The coating solution 60 is a solution obtained by dissolving any of the material for the first charge transport layer, the material for the photoactive layer, and the material for the second charge transport layer in a solvent. In this case, the coating liquid 60 contains a high molecular organic compound. The vapor pressure of the coating liquid 60 is preferably, for example, 100 Pascals (Pa) or more and 30000 Pa or less. The temperature at this time is 20 ° C., for example.

  By moving the coating head 20 relative to the coating object 50, a thin coating film of about 1 micrometer (μm) is uniformly provided on the coating object 50.

  As a method for forming a power generation layer on a substrate by dissolving a polymer organic material in a solvent and coating it, for example, a bar coating method, a roll coating method, a wire bar coating method, or the like is used. In these coating methods, the configuration of the coating apparatus is relatively simple.

  A general coating apparatus is suitable, for example, when a coating solution is continuously applied to a long rectangular coating object. In this case, a cylindrical coating head is used. However, such an application head cannot cope with the circular application object as described above.

  For example, in the case of a relatively small product such as a wristwatch, a region where a solar cell module can be mounted is limited. For this reason, a solar cell module is also suitably provided according to the shape of a product. That is, it is desirable that the coating apparatus can cope with various coating shapes other than the rectangular shape.

  Screen printing methods, gravure printing methods, flexographic printing methods, offset printing methods, gravure / offset printing methods, and the like can be applied to coating shapes other than rectangular shapes if a plate is produced. However, from the viewpoint of the viscosity of the coating liquid, the surface tension, the film thickness after coating, and the film thickness accuracy, it is not suitable for coating the coating liquid used for the solar cell module. There is also a method of dropping or flying the coating liquid using a dispenser method or an ink jet method. However, there are problems such as a minute uneven shape remaining and a long time required for coating, and it is not suitable for coating a coating solution used for a solar cell module.

  On the other hand, according to this embodiment, the coating head 20 is included. The coating head 20 rotates about the first axis 20r, and the width wt parallel to the first axis 20r changes along the circumferential direction D2. Then, the control unit 30 performs an operation of causing at least one of the coating head 20 and the stage 10 to move relative to each other in the first surface parallel to the upper surface 10u. Thereby, it can respond to application shapes other than rectangular shape. For example, it can apply | coat with respect to the circular application | coating object 50. FIG.

FIG. 2A to FIG. 2D are schematic perspective views in order of the processes, illustrating the operation of the coating apparatus according to the first embodiment.
The application target object 50 in this example is a circular substrate used for a solar cell module. In this example, the coating head 20 is moved from the outside of the coating object 50 toward the center along the first direction X1. Illustration of the stage 10 is omitted.

  As shown in FIG. 2A, the first layer 65 is provided on the application target object 50. The first layer 65 is a transparent electrode such as ITO (Indium Tin Oxide). The first layer 65 has, for example, a substantially fan shape. The first layer 65 is formed on the coating object 50 by using, for example, a sputtering method. On the application object 50, the substantially fan-shaped 1st layer 65 is provided in multiple places (for example, 8 places) along the circumferential direction.

  As shown in FIG. 2B, the coating liquid supply unit 40 supplies the coating liquid 60 between the first layer 65 and the coating head 20 in a state where the coating head 20 is brought close to the first layer 65. . The coating liquid 60 is, for example, a charge transport layer (electron transport layer or hole transport layer) material or a photoactive layer material. The control unit 30 performs an operation of moving on the first layer 65 along the first direction X1 while rotating the coating head 20 along the rotation direction D1.

  The coating head 20 includes a first region 21 having a first width wt1 and a second region 22 having a second width wt2 that is narrower than the first width wt1. The first region 21 faces the application target object 50 at the start position of the rotation operation of the application head 20. The first width wt1 is, for example, the maximum width of the coating head 20. Further, the second region 22 faces the application object 50 at the end position of the rotation operation of the application head 20. The second width wt2 is, for example, the minimum width of the coating head 20.

  As shown in FIG. 2C, the first layer 65 and the first region 21 are moved from the first state where the first layer 65 is opposed to the first layer 65 by moving the coating head 20 while rotating the coating head 20. 65 and the 2nd field 22 change to the 2nd state which counters. That is, the width of the coating liquid 60 held between the coating head 20 and the first layer 65 is continuously narrowed in the first direction X1. In this case, in order to make the thickness of the coating film constant, the relative moving speed of the coating head 20 (or the first layer 65) and the distance between the coating head 20 and the first layer 65 are controlled. It is realized with. In general, when coating is performed with an equal width, if the coating is performed while moving relatively, the coating liquid is consumed and the thickness of the coating film is reduced. For this reason, the thickness of the coating film is increased by increasing the relative moving speed and widening the interval.

  That is, according to the coating method according to the embodiment, the coating liquid is accumulated between the coating head and the coating object mainly due to the surface tension. When the relative moving speed is increased, the amount of coating liquid remaining on the coating object is overcome by overcoming the surface tension. For this reason, it is thought that the thickness of a coating film becomes thick. Further, when the interval is widened, the amount of the coating liquid that is accumulated between the coating head and the coating object decreases due to the surface tension, and the coating liquid that remains on the coating object increases. For this reason, it is thought that the thickness of a coating film becomes thick.

  In this embodiment, as shown in FIG. 2C, the coating width is gradually narrowed. In order to make the thickness of the coating film constant, the relative movement speed of the coating head 20 (or the first layer 65) and the distance between the coating head 20 and the first layer 65 should be appropriately controlled. Is preferred. For example, in order to make the thickness of the coating film constant, the relative movement speed in the first state (the state where the first layer 65 and the first region 21 face each other) is set to the second state (the first layer). 65 may be larger than the relative movement speed in a state where the second region 22 faces the second region 22. That is, when the width of the coating liquid 60 decreases in accordance with the movement of the coating head 20, the movement speed of the coating head 20 may be controlled to gradually decrease. Further, depending on the application shape (consumption amount of the coating liquid), the relative movement speed in the first state may be smaller than the relative movement speed in the second state.

  As shown in FIG. 2D, the coating liquid 60 is applied on the first layer 65 in a substantially fan shape. Then, the application object 50 is rotated along the rotation direction D <b> 3, and the same application operation is repeated for the next first layer 65. That is, this application | coating operation is implemented in multiple times (for example, 8 times). The coating liquid 60 is applied in a substantially fan shape on each of a plurality of (eight) first layers 65 provided on the application target 50.

FIG. 3 is a flowchart illustrating the coating method according to the first embodiment.
The coating apparatus 110 supplies the coating liquid 60 between the coating target 50 placed on the upper surface 10u of the stage 10 and the coating head 20 (step S1). While rotating the coating head 20 along the rotation direction D1, at least one of the coating head 20 and the stage 10 is moved relative to the first surface parallel to the upper surface 10u. In this example, it is relatively moved along the first direction X1 (step S2). Thereby, as shown in FIG.2 (d), the coating liquid 60 can be apply | coated to substantially fan shape. By repeating this application | coating operation | movement, it becomes possible to apply | coat with respect to circular application | coating object 50.

  The application object 50 is not limited to a circular shape. According to this embodiment, it can apply | coat with respect to the application | coating target of various planar shapes.

FIG. 4 is a schematic cross-sectional view illustrating a part of the solar cell module according to the first embodiment.
FIG. 4 illustrates a part of the organic thin film photovoltaic cell.
As shown in FIG. 4, the first charge transport layer 70a is, for example, a hole transport layer that transports holes and blocks electrons. The second charge transport layer 70b is, for example, an electron transport layer that transports electrons and blocks holes.

  An anode 72 including a transparent electrode is provided on the substrate 71. The first charge transport layer 70 a is provided on the anode 72. The photoactive layer (photoelectric conversion layer) 73 is provided on the first charge transport layer 70a. The second charge transport layer 70 b is provided on the photoactive layer 73. The photoactive layer 73 is a thin film in which a first conductivity type semiconductor layer 73n and a second conductivity type semiconductor layer 73p are bulk heterojunctioned. The cathode 74 is provided on the second charge transport layer 70b. A sealing film (not shown) is provided on the surface of the cell.

  The first charge transport layer 70a, the photoactive layer 73, and the second charge transport layer 70b are combined to form a power generation layer.

  The solar cell module according to the embodiment is, for example, a bulk heterojunction type. A feature of the bulk heterojunction type photoactive layer is that a p-type semiconductor and an n-type semiconductor are blended, and a nano-order pn junction spreads over the entire photoactive layer. For this reason, the pn junction region is wider than the conventional stacked organic thin film solar cell, and the region that actually contributes to power generation also extends to the entire photoactive layer. Accordingly, the region contributing to power generation in the bulk heterojunction type organic thin film solar cell is thicker than that of the stacked organic thin film solar cell. As a result, the absorption efficiency of photons is improved, and the current that can be extracted also increases.

  Hereinafter, members used for the solar cell module according to the present embodiment will be described.

(substrate)
The application target object 50 is, for example, a substrate 71. The substrate 71 supports other constituent members. For the substrate 71, for example, a material that does not change in quality due to heat accompanying the formation of electrodes or an organic solvent is used. As the material of the substrate 71, for example, an inorganic material such as non-alkali glass or quartz glass is used. The material of the substrate 71 may be, for example, a plastic such as polyethylene, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyimide, polyamide, polyamideimide, liquid crystal polymer, cycloolefin polymer, or a polymer film. As the substrate 71, a metal substrate such as stainless steel (SUS) or silicon may be used. For the substrate 71, for example, a light transmissive material is used. The thickness of the substrate 71 is not particularly limited as long as it has sufficient strength to support other components.

(anode)
The anode 72 is provided on the substrate 71. The anode 72 is made of a transparent or translucent conductive material. For the formation of the anode 72, for example, a vacuum deposition method, a sputtering method, an ion plating method, a plating method, a coating method, or the like is used. Examples of the material of the anode 72 include a conductive metal oxide film and a translucent metal thin film. Specifically, indium oxide, zinc oxide, tin oxide, indium tin oxide (ITO), fluorine-doped tin oxide (FTO), or indium zinc oxide, which is a composite thereof, is used as the metal oxide film. And a film manufactured using conductive glass containing the like. Gold, platinum, silver, copper, or the like is used as the material for the metal thin film. ITO or FTO is preferable as the material of the anode 72 having light transmittance. As a material of the light-transmitting anode 72, polyaniline which is an organic conductive polymer and derivatives thereof, polythiophene and derivatives thereof, and the like may be used.

  When ITO is used as the material of the anode 72, the thickness of the anode 72 is preferably 30 nanometers (nm) or more and 300 nm or less in the case of ITO. If it is thinner than 30 nm, the conductivity is lowered, the resistance is increased, and the photoelectric conversion efficiency is lowered. When it is thicker than 300 nm, the flexibility of ITO is lowered, and when stress is applied, the ITO may break. The sheet resistance of the anode 72 is preferably low, for example, 10Ω / □ (ohms square) or less. The anode 72 may be a single layer or a laminate of layers using materials having different work functions.

(First charge transport layer)
The coating liquid 60 includes, for example, a material for the first charge transport layer 70a. The first charge transport layer 70 a is disposed between the anode 72 and the photoactive layer 73. The first charge transport layer 70a levels the unevenness of the lower electrode to prevent a short circuit of the solar cell element. The first charge transport layer 70a efficiently transports only holes. The first charge transport layer 70 a prevents annihilation of excitons generated near the interface of the photoactive layer 73. For the first charge transport layer 70a, for example, an organic conductive polymer such as polythiophene polymer, polyaniline, or polypyrrole is used. As the polythiophene polymer, for example, PEDOT / PSS (poly (3,4-ethylenedioxythiophene) -poly (styrenesulfonate)) is used. Representative products of the polythiophene-based polymer include, for example, Clevios PH500, CleviosPH, CleviosPV P Al 4083, and CleviosHIL1.1 from Starck. For inorganic materials, molybdenum oxide is a suitable material.

  When Clevios PH500 is used as the material of the first charge transport layer 70a, the thickness of the first charge transport layer 70a is preferably 10 nm or more and 100 nm or less. When it is too thin, the effect | action which blocks an electron will fall. If it is too thick, the film resistance increases and the current generated in the photoactive layer 73 is limited, so that the light conversion efficiency decreases.

  For example, a coating method such as a spin coating method can be used to form the first charge transport layer 70a. After the material of the first charge transport layer 70a is applied to a desired thickness, it is heated and dried with a hot plate or the like. For example, it is preferable to heat and dry at 140 ° C. to 200 ° C. for about 1 minute to 10 minutes. As the solution to be applied, it is desirable to use a solution that has been filtered in advance.

(Photoactive layer)
The coating liquid 60 contains the material of the photoactive layer (photoelectric conversion layer) 73, for example. The photoactive layer 73 is disposed between the anode 72 and the cathode 74. The photoactive layer 73 includes a first conductivity type first semiconductor layer 73n and a second conductivity type second semiconductor layer 73p. For example, the first semiconductor layer 73n is provided between the second charge transport layer 70b and the second semiconductor layer 73p. For example, the first conductivity type is n-type and the second conductivity type is p-type. The first conductivity type may be p-type and the second conductivity type may be n-type.

  The photoactive layer 73 is, for example, a thin film having a structure in which a first semiconductor layer 73n and a second semiconductor layer 73p are bulk heterojunctioned. The feature of the bulk heterojunction photoactive layer is that an n-type semiconductor and a p-type semiconductor are blended, and a nano-order pn junction spreads over the entire photoelectric conversion layer. This structure is called, for example, a micro layer separation structure.

  In the bulk heterojunction type photoactive layer 73, current is obtained by utilizing photocharge separation generated at the junction surface of the mixed p-type semiconductor and n-type semiconductor. A material having an electron donating property is used for the p-type semiconductor. On the other hand, a material having an electron accepting property is used for the n-type semiconductor. In the embodiment, an organic semiconductor is used for at least one of a p-type semiconductor and an n-type semiconductor.

  Examples of the p-type organic semiconductor include polythiophene and derivatives thereof, polypyrrole and derivatives thereof, pyrazoline derivatives, arylamine derivatives, stilbene derivatives, triphenyldiamine derivatives, oligothiophene and derivatives thereof, polyvinylcarbazole and derivatives thereof, polysilane and derivatives thereof. Polysiloxane derivatives having an aromatic amine in the side chain or main chain, polyaniline and derivatives thereof, phthalocyanine derivatives, porphyrin and derivatives thereof, polyphenylene vinylene and derivatives thereof, polythienylene vinylene and derivatives thereof, and the like can be used. These may be used in combination. These copolymers may be used. Examples of the copolymer include a thiophene-fluorene copolymer, a phenyleneethynylene-phenylenevinylene copolymer, and the like.

  A preferred p-type organic semiconductor is polythiophene, which is a conductive polymer having π conjugation, and derivatives thereof. Polythiophene and its derivatives can ensure excellent stereoregularity and have relatively high solubility in solvents. Polythiophene and derivatives thereof are not particularly limited as long as they are compounds having a thiophene skeleton. Specific examples of polythiophene and derivatives thereof include, for example, polyalkylthiophene, polyarylthiophene, polyalkylisothionaphthene and polyethylenedioxythiophene. Examples of the polyalkylthiophene include poly-3-methylthiophene, poly-3-butylthiophene, poly-3-hexylthiophene, poly-3-octylthiophene, poly-3-decylthiophene, and poly-3-dodecylthiophene. Examples of polyarylthiophene include poly-3-phenylthiophene and poly-3- (p-alkylphenylthiophene). Examples of the polyalkylisothionaphthene include poly-3-butylisothionaphthene, poly-3-hexylisothionaphthene, poly-3-octylisothionaphthene, and poly-3-decylisothionaphthene.

  PCDTBT (poly [N-9 "-hepta-decanyl-2,7-carbazole-alt-5,5- (4 ', 7'-di-2) which is a copolymer of carbazole, benzothiadiazole and thiophene. Derivatives such as -thienyl-2 ', 1', 3'-benzothiadiazole)]) are compounds that can obtain excellent photoelectric conversion efficiency.

  These conductive polymer films can be formed by applying a solution dissolved in a solvent. Therefore, a large-area organic thin film solar cell can be manufactured at low cost with inexpensive equipment by a printing method or the like.

  As the n-type organic semiconductor, fullerene and its derivatives are preferably used. The fullerene derivative used here is not particularly limited as long as it is a derivative having a fullerene skeleton. Specifically, derivatives composed of C60, C70, C76, C78, C84 and the like as a basic skeleton can be given. In the fullerene derivative, the carbon atom in the fullerene skeleton may be modified with any functional group. These functional groups may be bonded to each other to form a ring. Fullerene derivatives also include fullerene bonded polymers. A fullerene derivative having a functional group with high affinity for the solvent and high solubility in the solvent is preferred.

  Examples of the functional group in the fullerene derivative include a hydrogen atom, a hydroxyl group, a halogen atom, an alkyl group, an alkenyl group, a cyano group, an alkoxy group, and an aromatic heterocyclic group. Examples of the halogen atom include a fluorine atom and a chlorine atom. Examples of the alkyl group include a methyl group and an ethyl group. Examples of the alkenyl group include a vinyl group. Examples of the alkoxy group include a methoxy group and an ethoxy group. Examples of the aromatic heterocyclic group include an aromatic hydrocarbon group, a thienyl group, and a pyridyl group. Moreover, as an aromatic hydrocarbon group, a phenyl group, a naphthyl group, etc. are mentioned, for example. More specifically, a hydrogenated fullerene, an oxide fullerene, a fullerene metal complex, etc. are mentioned. Examples of the hydrogenated fullerene include C60H36 and C70H36. Examples of the oxide fullerene include C60 and C70. Among the above-mentioned, it is particularly preferable to use 60PCBM ([6,6] -phenyl C61 butyric acid methyl ester) or 70PCBM ([6,6] -phenyl C71 butyric acid methyl ester) as the fullerene derivative. When using unmodified fullerene, it is preferable to use C70. Fullerene C70 has high photocarrier generation efficiency and is suitable for use in organic thin-film solar cells.

  When the p-type semiconductor is P3AT-based, the mixing ratio of the n-type organic semiconductor and the p-type organic semiconductor in the photoactive layer 73 is preferably about n: p = 1: 1. When the p-type semiconductor is a PCDTBT system, the mixing ratio is preferably approximately n: p = 4: 1.

  The organic semiconductor can be applied by dissolving the organic semiconductor in a solvent. Examples of the solvent used for coating include unsaturated hydrocarbon solvents, halogenated aromatic hydrocarbon solvents, halogenated saturated hydrocarbon solvents, and ethers. Examples of the unsaturated hydrocarbon solvent include toluene, xylene, tetralin, decalin, mesitylene, n-butylbenzene, sec-butylbenzene, and tert-butylbenzene. Examples of the halogenated aromatic hydrocarbon solvent include chlorobenzene, dichlorobenzene, and trichlorobenzene. Examples of the halogenated saturated hydrocarbon solvent include carbon tetrachloride, chloroform, dichloromethane, dichloroethane, chlorobutane, bromobutane, chloropentane, chlorohexane, bromohexane, and chlorocyclohexane. Examples of ethers include tetrahydrofuran and tetrahydropyran. In particular, a halogen-based aromatic solvent is preferable. These solvents can be used alone or in combination.

  As a method of forming a film by applying a solution, spin coating method, dip coating method, casting method, bar coating method, roll coating method, wire bar coating method, spray method, screen printing, gravure printing method, flexographic printing method , Offset printing method, gravure / offset printing, dispenser coating, nozzle coating method, capillary coating method, and inkjet method. These coating methods may be used alone or in combination.

(Second charge transport layer)
The coating liquid 60 includes, for example, a material for the second charge transport layer 70b. The second charge transport layer 70 b is disposed between the cathode 74 and the photoactive layer 73. The second charge transport layer 70b blocks holes and efficiently transports only electrons. The second charge transport layer 70b prevents the disappearance of excitons generated at the interface between the photoactive layer 73 and the second charge transport layer 70b.

  For example, a metal oxide is used as the material of the second charge transport layer 70b. Examples of the metal oxide include amorphous titanium oxide obtained by hydrolyzing titanium alkoxide by a sol-gel method. The method for forming the film of the second charge transport layer 70b is not particularly limited as long as it is a method capable of forming a thin film. For example, a method of forming the second charge transport layer 70b includes a spin coating method. When titanium oxide is used as the material of the second charge transport layer 70b, the thickness of the second charge transport layer 70b is preferably, for example, 5 nm or more and 50 nm or less. When the thickness of the second charge transport layer 70b is thinner than the above range, the hole blocking effect is lowered. For this reason, the exciton generated in the photoactive layer 73 is deactivated before dissociating into electrons and holes, and the current cannot be extracted efficiently. When the thickness of the second charge transport layer 70b is too thick, the film resistance increases and current generated in the photoactive layer 73 is limited. For this reason, light conversion efficiency falls. The solution to be applied is preferably filtered through a filter in advance. After applying the solution to a desired thickness, it is heated and dried using a hot plate or the like. Heating and drying are performed at a temperature of 50 ° C. to 100 ° C. for about 1 minute to 10 minutes. Heating and drying are performed while promoting hydrolysis in the air. When an inorganic material is used, metallic calcium or the like is a suitable material.

(cathode)
The cathode 74 is provided on the second charge transport layer 70b. The material of the cathode 74 is not particularly limited as long as it is a conductive material. For forming the cathode 74, a vacuum deposition method, a sputtering method, an ion plating method, a plating method, a coating method, or the like is used. Accordingly, a film containing a conductive material can be formed as an electrode. Examples of the material of the electrode include a conductive metal thin film and a conductive metal oxide film.

  The anode 72 is formed using, for example, a material having a high work function. In this case, it is preferable to use a material having a low work function for the cathode 74. Examples of the material having a low work function include alkali metals and alkaline earth metals. Specific examples include Li, In, Al, Ca, Mg, Sm, Tb, Yb, Zr, Na, K, Rb, Cs, Ba, and alloys thereof. Alternatively, an alloy of at least one of these materials having a low work function with gold, silver, platinum, copper, manganese, titanium, cobalt, nickel, tungsten, tin, or the like may be used. Examples of alloys include lithium-aluminum alloys, lithium-magnesium alloys, lithium-indium alloys, magnesium-silver alloys, magnesium-indium alloys, magnesium-aluminum alloys, indium-silver alloys, and calcium-aluminum alloys. It is done.

  The cathode 74 may be a single layer or a stack of layers made of materials having different work functions.

  The thickness of the cathode 74 is, for example, not less than 10 nm and not more than 300 nm. When the thickness of the cathode 74 is smaller than this range, the resistance becomes too large and the charge generated in the photoactive layer 73 cannot be sufficiently transmitted to the external circuit. When the thickness of the cathode 74 is thick, it takes a long time to form the cathode 74, so that the material temperature rises, and the photoactive layer 73 may be damaged to deteriorate the performance. Furthermore, since a large amount of material is used, the occupation time of the manufacturing apparatus becomes long, leading to an increase in cost.

  The case where the first charge transport layer 70a is a hole transport layer and the second charge transport layer 70b is an electron transport layer has been described above. For example, in a configuration called a reverse configuration in which the transparent electrode is the cathode and the counter electrode is the anode, from the substrate 71 side, the cathode (transparent electrode), the second charge transport layer (electron transport layer), the photoactive layer, the first The structure is a charge transport layer (hole transport layer) and an anode (counter electrode).

FIG. 5 is a schematic cross-sectional view illustrating another solar cell module according to the first embodiment.
FIG. 5 shows a cross section of a solar cell module having a structure in which a plurality of organic thin-film solar cells are connected in series.
The configuration in FIG. 5 is the reverse of the configuration in FIG. 4, and from the substrate 71 side, the cathode (transparent electrode), the second charge transport layer (electron transport layer), the photoactive layer, and the first charge transport layer. (Hole transport layer) and anode (counter electrode).

  As shown in FIG. 5, a cathode 74 is provided on the substrate 71. A second charge transport layer 70 b is provided on the cathode 74. A photoactive layer 73 is provided on the second charge transport layer 70b. A first charge transport layer 70 a is provided on the photoactive layer 73. An anode 72 is provided on the first charge transport layer 70a.

FIG. 6A to FIG. 6C are schematic plan views in order of the processes, illustrating the method for manufacturing the solar cell module according to the first embodiment.
In this example, application is performed from the outside of the application object 50 toward the center, and the solar cell module of FIG. 5 is manufactured.

  As shown in FIG. 6A, a film of the cathode 74 is formed on the substrate 71 and patterned. The substrate 71 has a circular shape, for example. In this example, a solar cell module in which a plurality (eight) of substantially fan-shaped cells are connected in series is manufactured. The film of the cathode 74 is formed on the entire surface of the substrate 71 using, for example, a sputtering method, and then patterned into a substantially fan shape using an etching method.

  As shown in FIG. 6B, the second charge transport layer 70 b is formed in a substantially fan shape on the cathode 74 using the coating apparatus 110. Further, using the coating device 110, the photoactive layer 73 is formed in a substantially fan shape on the second charge transport layer 70b.

  As shown in FIG. 6C, the first charge transport layer 70 a is formed in a substantially fan shape on the photoactive layer 73 using the coating apparatus 110. Finally, the anode 72 is formed on the first charge transport layer 70a by vapor deposition or the like. Thereby, the solar cell module shown in FIG. 5 is obtained.

(Second Embodiment)
FIG. 7A to FIG. 7D are schematic perspective views in order of the processes, illustrating the operation of the coating apparatus according to the second embodiment.

  The application target object 50 in this example is a circular substrate used for a solar cell module. In this example, the coating head 20 is moved outward from the center of the coating object 50 along the first direction X1. Illustration of the stage 10 is omitted.

  As shown in FIG. 7A, a first layer 65 is provided on the application target object 50. The first layer 65 is a transparent electrode such as ITO. The first layer 65 has, for example, a substantially fan shape. The first layer 65 is formed on the coating object 50 by using, for example, a sputtering method. On the application object 50, the substantially fan-shaped 1st layer 65 is provided in multiple places (for example, 8 places) along the circumferential direction.

  As shown in FIG. 7B, the coating liquid supply unit 40 supplies the coating liquid 60 between the first layer 65 and the coating head 20 in a state where the coating head 20 is brought close to the first layer 65. . The coating liquid 60 is, for example, a charge transport layer (electron transport layer or hole transport layer) material or a photoactive layer material. The control unit 30 performs an operation of moving on the first layer 65 along the first direction X1 while rotating the coating head 20 along the rotation direction D1.

  The coating head 20 includes a first region 21 having a first width wt1 and a second region 22 having a second width wt2 that is narrower than the first width wt1. The second region 22 faces the application target object 50 at the start position of the rotation operation of the application head 20. The second width wt2 is, for example, the minimum width of the coating head 20. Further, the first region 21 faces the application target object 50 at the end position of the rotation operation of the application head 20. The first width wt1 is, for example, the minimum width of the coating head 20.

  As shown in FIG. 7C, the first layer 65 and the second region 22 are moved from the second state in which the first layer 65 is opposed to the first layer 65 by moving the coating head 20 while rotating the coating head 20. 65 and the 1st field 21 change to the 1st state which counters. That is, the width of the coating liquid 60 held between the coating head 20 and the first layer 65 is continuously widened in the first direction X1. In this case, in order to make the thickness of the coating film constant, the relative moving speed of the coating head 20 (or the first layer 65) and the distance between the coating head 20 and the first layer 65 are controlled. It is realized with. In general, when coating is performed with an equal width, if the coating is performed while moving relatively, the coating liquid is consumed and the thickness of the coating film is reduced. For this reason, the thickness of the coating film is increased by increasing the relative moving speed and widening the interval.

  That is, according to the coating method according to the embodiment, the coating liquid is accumulated between the coating head and the coating object mainly due to the surface tension. When the relative moving speed is increased, the amount of coating liquid remaining on the coating object is overcome by overcoming the surface tension. For this reason, it is thought that the thickness of a coating film becomes thick. Further, when the interval is widened, the amount of the coating liquid that is accumulated between the coating head and the coating object decreases due to the surface tension, and the coating liquid that remains on the coating object increases. For this reason, it is thought that the thickness of a coating film becomes thick.

  In the present embodiment, as shown in FIG. 7C, the coating width gradually increases. In order to make the thickness of the coating film constant, the relative movement speed of the coating head 20 (or the first layer 65) and the distance between the coating head 20 and the first layer 65 should be appropriately controlled. Is preferred. For example, when the moving speed and the interval are constant, the thickness of the coating film in the first region 21 having a large coating width is considered to be thinner than the thickness of the coating film in the second region 22 having a narrow coating width.

  In such a case, in order to make the thickness of the coating film constant, the relative movement speed in the first state (the state where the first layer 65 and the first region 21 face each other) is set to the second state ( It is preferable to make it larger than the relative movement speed in the state in which the first layer 65 and the second region 22 face each other. That is, when the width of the coating liquid 60 increases in accordance with the movement of the coating head 20, it is preferable that the movement speed of the coating head 20 be controlled so as to gradually increase.

  In the present embodiment, the coating head 20 moves outward from the center of the coating object 50. For this reason, the liquid absorbing sheet 55 is provided outside the outer edge portion of the application target object 50. The liquid absorbing sheet 55 absorbs the coating liquid 60 that protrudes due to the movement of the coating head 20. Thereby, the excess coating liquid 60 can be collect | recovered.

  As shown in FIG. 7D, the coating liquid 60 is applied on the first layer 65 in a substantially fan shape. Then, the application object 50 is rotated along the rotation direction D <b> 3, and the same application operation is repeated for the next first layer 65. That is, this application | coating operation is implemented in multiple times (for example, 8 times). The coating liquid 60 is applied in a substantially fan shape on each of a plurality of (for example, eight) first layers 65 provided on the coating object 50.

  According to this embodiment, compared with the example of FIG. 2D in the first embodiment, application to the outermost edge of the application object 50 is possible. For this reason, the application area of the coating liquid 60 can be made larger.

FIG. 8A to FIG. 8C are schematic plan views in order of the processes, illustrating the method for manufacturing the solar cell module according to the second embodiment.
In this example, unlike the examples of FIGS. 6A to 6C, coating is performed from the center of the coating object 50 toward the outside, and the solar cell module of FIG. 5 is manufactured.

  As shown in FIG. 8A, a film of the cathode 74 is formed on the substrate 71 and patterned. The substrate 71 has a circular shape, for example. In this example, a solar cell module in which a plurality of (for example, eight) substantially fan-shaped cells are connected in series is manufactured. The film of the cathode 74 is formed on the entire surface of the substrate 71 using, for example, a sputtering method, and then patterned into a substantially fan shape using an etching method.

  As shown in FIG. 8B, the second charge transport layer 70 b is formed in a substantially fan shape on the cathode 74 using the coating apparatus 110. Further, using the coating device 110, the photoactive layer 73 is formed in a substantially fan shape on the second charge transport layer 70b.

  As illustrated in FIG. 8C, the first charge transport layer 70 a is formed in a substantially fan shape on the photoactive layer 73 using the coating apparatus 110. Finally, the anode 72 is formed on the first charge transport layer 70a by vapor deposition or the like. Thereby, the solar cell module shown in FIG. 5 is obtained.

  As described above, in the above-described two embodiments, when the coating head 20 moves relative to the coating target 50, the moving speed of the coating head 20, the distance between the coating head 20 and the coating target 50, By controlling the above, it is possible to obtain a coating film having a uniform thickness.

(Third embodiment)
FIG. 9A and FIG. 9B are schematic perspective views illustrating the operation of the coating apparatus according to the third embodiment.

  The application target object 50 in this example is a circular substrate used for a solar cell module. The control unit 30 causes at least one of the coating head 20 and the stage 10 to perform a relative movement along the first direction X1 on the first surface, and at least one of the coating head 20 and the stage 10. In addition, a second operation for causing relative movement along the second direction Y2 on the first surface is performed. The second direction Y2 is a direction that intersects the first direction X1. In this example, the coating head 20 is relatively moved from the center of the coating object 50 toward the outside. The first direction X1 is, for example, along the X-axis direction. The second direction Y2 is, for example, along the Y-axis direction.

  The application is not limited to a substantially fan shape. Application can correspond to any shape. In this case, the application head 20 may be applied while moving along the first direction X1 and further moving along the second direction Y2.

  For example, the position of the coating head 20 is fixed. Then, the stage 10 is moved along the first direction X1 and the second direction Y2 while rotating the coating head 20 along the rotation direction D1. The stage 10 is a moving stage that can move freely in the X-axis direction and the Y-axis direction, for example.

  As shown to Fig.9 (a), the 1st layer 65 of arbitrary shapes is provided on a part of the application target object 50. FIG. The first layer 65 is a transparent electrode such as ITO. The first layer 65 is formed on the coating object 50 by using, for example, a sputtering method.

  As shown in FIG. 9B, the coating liquid supply unit 40 supplies the coating liquid 60 between the first layer 65 and the coating head 20 in a state where the coating head 20 is brought close to the first layer 65. . The coating liquid 60 is, for example, a charge transport layer (electron transport layer or hole transport layer) material or a photoactive layer material. The control unit 30 rotates the coating head 20 along the rotation direction D1 and moves the first layer 65 along the first direction X1 and the first layer along the second direction Y2. And a second operation of moving over 65.

  According to this embodiment, when relatively moving at least one of the coating head 10 and the coating object 50, in addition to the first operation along the first direction X1, the second along the second direction Y2. Perform the operation. For this reason, it can respond to more application shapes.

FIG. 10 is a schematic plan view illustrating a solar cell module according to the third embodiment.
As shown in FIG. 10, the solar cell module according to the embodiment includes a plurality of solar cells 90 provided on a substrate. The plurality of solar cells 90 include, for example, first solar cells 91 and second solar cells 92. A solar cell module is a solar cell module used for a wristwatch, for example.

  Each planar shape (shape projected on the XY plane) of the plurality of solar cells 90 is different from each other. For example, the planar shape of the first solar cell 91 is different from the planar shape of the second solar cell 92. The area of the first solar cell 91 may be different from the area of the second solar cell 92.

  For example, the first solar battery cell 91 has an end portion 91e that extends in a direction different from the direction (Y-axis direction) in which the connection region R1 extends when projected onto the XY plane. The second solar battery cell 92 has an end portion 92e extending in a direction different from the direction in which the connection region R1 extends and the direction in which the end portion 91e extends when projected onto the XY plane. The end 91e and the end 92e may be curved.

  The area of the place where the solar cell module for a wristwatch is installed is limited. For this reason, the cell which comprises a solar cell module may not be the same shape. Solar cell modules for wristwatches are often not circular in design. Moreover, the installation place of a solar cell module is limited, such as avoiding the place of the display which displays a date and a day of the week. For this reason, the shape of the cell which comprises a solar cell module may differ one by one.

  On the other hand, according to this embodiment, the coating head 20 can be moved in accordance with an arbitrary coating shape. Thereby, it can respond also to a solar cell module as shown in FIG.

  As described above, the application apparatus and the application method using the application apparatus have been described as examples. However, in the embodiment, a form of an application program for causing a computer to execute the application method, or a computer reading that records the application program. A possible recording medium may be used.

  Specific examples of the recording medium include CD-ROM (-R / -RW), magneto-optical disk, HD (hard disk), DVD-ROM (-R / -RW / -RAM), and FD (flexible disk). ), A flash memory, a memory card, a memory stick, and various other ROMs and RAMs can be assumed, and the application program for causing the computer to execute the application method of the present embodiment described above is recorded and distributed on these recording media. This facilitates the realization of the method. Then, the recording medium as described above is mounted on an information processing apparatus such as a computer and the application program is read by the information processing apparatus, or the application program is stored in a storage medium provided in the information processing apparatus, By reading out accordingly, the coating method of the present embodiment can be executed.

  According to the embodiment, it is possible to provide a coating apparatus, a coating method, and a coating program that can be applied to a coating object having various planar shapes.

  The embodiments of the present invention have been described above with reference to specific examples. However, the present invention is not limited to these specific examples. For example, regarding the specific configuration of each element such as a stage, a coating head, and a control unit, those skilled in the art can appropriately perform the present invention by appropriately selecting from a well-known range and obtain similar effects. Are included within the scope of the present invention.

  Moreover, what combined any two or more elements of each specific example in the technically possible range is also included in the scope of the present invention as long as the gist of the present invention is included.

  In addition, all coating apparatuses, coating methods, and coating programs that can be implemented by those skilled in the art based on the coating apparatus, the coating method, and the coating program described above as the embodiment of the present invention. As long as the gist of the invention is included, it belongs to the scope of the present invention.

  In addition, in the category of the idea of the present invention, those skilled in the art can conceive of various changes and modifications, and it is understood that these changes and modifications also belong to the scope of the present invention. .

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 10 ... Stage, 20 ... Application | coating head, 20r ... 1st axis | shaft, 21 ... 1st area | region, 22 ... 2nd area | region, 30 ... Control part, 40 ... Application liquid supply part, 50 ... Application | coating object, 55 ... Absorption sheet 60 ... coating solution, 65 ... first layer, 70a ... first charge transport layer, 70b ... second charge transport layer, 71 ... substrate, 72 ... anode, 73 ... photoactive layer, 73n ... first semiconductor layer, 73p 2nd semiconductor layer, 74 ... cathode, 90 ... solar cell, 91 ... 1st solar cell, 91e, 92e ... end, 92 ... 2nd solar cell, 110 ... coating device, D1, D3 ... rotating direction D2 ... circumferential direction, X1 ... first direction, Y2 ... second direction, R1 ... connection region, wt ... width, wt1, wt2 ... first, second width

Claims (11)

A stage including an upper surface;
A coating head that rotates about a first axis substantially parallel to the top surface;
A control unit;
With
The width of the coating head in the first axial direction changes along a circumferential direction centered on the first axis;
The said control part is an application | coating apparatus which implements the operation | movement which makes a relative movement substantially parallel with respect to the said upper surface at least any one of the said coating head and the said stage. A coating liquid supply unit configured to supply a coating liquid between the coating target placed on the upper surface and the coating head;
The coating apparatus according to claim 1, wherein the control unit performs the operation while rotating the coating head in a state where the coating liquid is supplied between the coating target and the coating head.   The coating apparatus according to claim 1, wherein the width changes continuously. The coating head includes a first region and a second region having a circumferential position different from the first region,
The width in the first region is wider than the width in the second region,
The relative movement in the first state when the application object and the first region are changed from the first state to the second state in which the application object and the second region are opposite to each other. The coating apparatus according to any one of claims 1 to 3, wherein the speed of is different from the speed of the relative movement in the second state. The coating head includes a first region and a second region having a circumferential position different from the first region,
The width in the first region is wider than the width in the second region,
The relative movement in the first state when the application object and the second region change from the second state in which the application object and the second region face each other to the first state in which the application object and the first region face each other. The coating apparatus according to any one of claims 1 to 3, wherein the speed of is higher than the speed of the relative movement in the second state. The width in the first region includes the maximum width of the coating head;
The coating apparatus according to claim 4, wherein the width in the second region includes a minimum width of the coating head. The operation is
A first operation of causing at least one of the coating head and the stage to move relatively along a first direction substantially parallel to the upper surface ;
A second operation of causing at least one of the coating head and the stage to move relatively along a second direction substantially parallel to the upper surface and intersecting the first direction;
The coating apparatus according to any one of claims 1 to 6.   The coating apparatus according to any one of claims 1 to 7, wherein a cross section when a part of the coating head is cut in a direction orthogonal to the first axis is circular.   The coating apparatus according to claim 2, wherein the coating head faces the coating target object in a non-contact state. The coating solution contains a polymer organic compound,
The coating apparatus according to any one of claims 2 to 9, wherein a vapor pressure of the coating liquid is 100 Pascals or more and 30000 Pascals or less. A coating object that is placed on the upper surface of the stage, and a coating head that rotates about a first axis that is substantially parallel to the upper surface, wherein the width of the coating head in the first axis direction is the first axis Supplying a coating liquid between the coating head and the coating head that changes along the circumferential direction of the center;
While rotating the coating head, at least one of the coating head and the stage, a step of relative movement substantially parallel to said top surface,
A coating method comprising: