Photoelectric conversion element and method for manufacturing the same

Abstract

To provide a photoelectric conversion element with improved durability and a method for manufacturing the same.SOLUTION: A photoelectric conversion element 11 in an aspect of the present invention includes a substrate 12, a bottom electrode layer 13, a functional layer 14, a top electrode layer 15, and a barrier layer 16, in at least part of the photoelectric conversion element 11, the substrate 12, the bottom electrode layer 13, the functional layer 14, and the top electrode layer 15 are stacked in this order, the functional layer 14 includes an active layer 18, and a laminate including the substrate 12, the bottom electrode layer 13, the functional layer 14, and the top electrode layer 15 is sealed by the barrier layer 16.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a photoelectric conversion element and a method for manufacturing the same. [Background technology]

[0002] Solar cells, particularly thin-film solar cells made of microcrystalline, silicon, cadmium, organic, etc., have been expected to be one of the means to solve the energy problems of the next generation. Thin-film solar cells are manufactured by thinning materials, and several manufacturing methods are known.

[0003] Thinning is achieved by thin-film coating of each layer constituting a solar cell. For example, for organic thin-film solar cells, methods using wet coating methods such as spin coating, inkjet coating, and gravure coating are known as methods for manufacturing active layers, electron transport layers, hole transport layers, and the like (hereinafter, these are also collectively referred to as functional layers) (see, for example, Patent Documents 1 and 2). These methods can also be used to manufacture functional layers constituting other photoelectric conversion elements.

[0004] In order to increase the photoelectric conversion efficiency of a photoelectric conversion element, it is necessary to reduce light loss due to light reflection within the element, light loss due to charge recombination, light loss due to incomplete energy utilization, electrical loss due to resistance, and the like.

[0005] Since the surface of the active layer of a photoelectric conversion element has a large refractive index, there is a concern that light loss due to light reflection will increase. In order to reduce the light loss, a texture is formed on the surface of the active layer as an antireflection structure, as described below.

[0006] In the case of producing solar cells from silicon wafers, a method has been disclosed in which the silicon wafer is immersed in an alkaline solution such as potassium hydroxide and texture is formed by utilizing the anisotropy of the etching rate due to the crystal orientation (see Patent Document 3).

[0007] In the type in which a transparent conductive film is formed on a substrate, a method has been disclosed in which a texture is formed by etching the transparent conductive film with an acidic solution such as acetic acid or hydrochloric acid, or an alkaline solution such as sodium hydroxide (see Patent Document 4).

[0008] In the case of a type in which a transparent conductive film is formed on a substrate, a method has been disclosed in which a texture is formed by introducing boron during the production of the transparent conductive film by sputtering or CVD (see Patent Document 5). [Prior art documents] [Patent documents]

[0009] [Patent Document 1] JP 2016-051805 A [Patent Document 2] JP 2013-089807 A [Patent Document 3] JP 2004-281758 A [Patent Document 4] JP 2005-72332 A [Patent Document 5] JP 2000-252504 A Summary of the Invention [Problem to be solved by the invention]

[0010] In such photoelectric conversion elements, the performance may deteriorate due to the intrusion of oxygen or moisture into the inside, and the element may not be able to withstand long-term use, and therefore there is a demand for improved durability. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a photoelectric conversion element having improved durability and a method for manufacturing the same. [Means for solving the problem]

[0011] The present invention may include the following aspects. [1] A photoelectric conversion element comprising a substrate, a lower electrode layer, a functional layer, an upper electrode layer, and a barrier layer, wherein in at least a portion of the photoelectric conversion element, the substrate, the lower electrode layer, the functional layer, and the upper electrode layer are stacked in that order, the functional layer including an active layer, and the stack including the substrate, the lower electrode layer, the functional layer, and the upper electrode layer is sealed by the barrier layer. [2] The photoelectric conversion element according to [1], wherein the lower electrode layer is a light-transmitting electrode layer. [3] The photoelectric conversion element according to [1] or [2], wherein the substrate is made of glass or a film. [4] A method for producing a photoelectric conversion element according to any one of [1] to [3], comprising the step of forming the upper electrode layer by vapor deposition of a metal or by applying a paste containing a metal. Effect of the Invention

[0012] A photoelectric conversion element having improved durability and a method for manufacturing the same are provided. [Brief description of the drawings]

[0013] [Figure 1] 1 is a cross-sectional view taken along a plane perpendicular to a substrate in an example of a photoelectric conversion element of the present invention. [Diagram 2] FIG. 1 is a pattern diagram of a substrate with ITO used in the present invention. [Diagram 3] FIG. 2 is a diagram of a film formed by stacking an electron transport layer, an active layer, and a hole transport layer used in the present invention after scribing. [Figure 4] FIG. 2 is a view after application of the upper electrode layer used in the present invention. [Diagram 5] FIG. 13 is a view after the barrier layer used in the present invention is attached. [Figure 6] FIG. 2 is a view of a film formed by laminating an electron transport layer and an active layer used in the present invention after scribing. [Figure 7] FIG. 2 is a view after application of the upper electrode layer used in the present invention. [Figure 8] FIG. 2 is a diagram of a photoelectric conversion element with an extraction electrode used in the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, preferred embodiments of the present invention will be described in detail. The following description of the components may be based on representative embodiments and specific examples, but the present invention is not limited to such embodiments.

[0015] In the numerical ranges described in stages in this specification, the upper or lower limit of a certain numerical range can be arbitrarily combined with the upper or lower limit of another numerical range. In addition, in the numerical ranges described in this specification, the upper or lower limit of the numerical range may be replaced with a value shown in an example or a value that can be unambiguously derived from an example. Furthermore, in this specification, a numerical value connected with "~" means a numerical range that includes the numerical values ​​before and after "~" as the lower and upper limits.

[0016] In this specification, the expressions "contain" and "comprise" include the concepts of "contain", "comprise", "consist essentially of" and "consist only of". In this specification, "A and / or B" means "one of A and B" or "both A and B", specifically "A", "B", or "A and B".

[0017] In this specification, the relationship between two components A and B may be described as "component B is provided on component A" or "component B is provided on the upper surface of component A." Such descriptions are intended to allow not only cases where components A and B are in direct contact with each other, but also cases where another component is present between them to the extent that the effect is not impaired.

[0018] The present invention relates to a photoelectric conversion element and a manufacturing method thereof. A photoelectric conversion element is an element that converts light energy to electrical energy. Photoelectric conversion elements include organic EL devices that emit light by the action of excitons formed by the recombination of electrons and holes, organic thin-film solar cells that convert light into electricity, and organic thin-film transistors that control the amount of current or voltage.

[0019] In this specification, the terms "upper" and "lower" do not mean the top and bottom, and for example, with respect to the upper electrode layer and the lower electrode layer, the electrode layer disposed on the substrate side of a pair of electrode layers sandwiching a functional layer is defined as the lower electrode layer, and the electrode layer disposed on the opposite side to the substrate is defined as the upper electrode layer, and the terms "upper" and "lower" are simply defined. In addition, in this specification, "surface" refers to the surface closer to the upper electrode layer, unless otherwise specified.

[0020] [Example of photoelectric conversion element configuration] 1 shows an example of the configuration of a photoelectric conversion element 11 according to the first embodiment. The photoelectric conversion element 11 includes, for example, a substrate 12, a lower electrode layer 13, a functional layer 14, an upper electrode layer 15, and a barrier layer 16. The functional layer 14 includes, for example, an electron transport layer 17, an active layer 18, and a hole transport layer 19. The photoelectric conversion element 11 includes, for example, a sealant 20. In at least a part of the photoelectric conversion element 11, a substrate 12, a lower electrode layer 13, a functional layer 14, and an upper electrode layer 15 are laminated in this order. In the example of Fig. 1, the laminated structure includes the lower electrode layer 13, an electron transport layer 17, an active layer 18, a hole transport layer 19, and an upper electrode layer 15 laminated in this order on the substrate 12.

[0021] The laminate including the substrate 12, the lower electrode layer 13, the functional layer 14, and the upper electrode layer 15 is sealed by the barrier layer 16. More specifically, the laminate including the substrate 12, the lower electrode layer 13, the functional layer 14, and the upper electrode layer 15 has a structure sealed by the barrier layer 16 and the sealing material 20.

[0022] The structure shown in Fig. 1 may also be referred to as an inverted structure, and the present specification will mainly describe the case where the photoelectric conversion element 11 has an inverted structure. However, the configuration of the photoelectric conversion element 11 shown in Fig. 1 is merely an example. The photoelectric conversion element 11 may have a structure that may also be referred to as a normal structure, for example, in which a lower electrode layer 13 is provided on a substrate 12, a hole transport layer 19 is provided on the lower electrode layer 13, an active layer 18 is provided on the hole transport layer 19, an electron transport layer 17 is provided on the active layer 18, and an upper electrode layer 15 is provided on the electron transport layer 17. The substrate, lower electrode layer, functional layer, upper electrode layer, and barrier layer will be described in this order below.

[0023] <Substrate> The constituent material of the substrate is not particularly limited and is appropriately set according to the application of the photoelectric conversion element. For example, inorganic materials such as quartz, glass, sapphire, titania, etc.; organic materials such as polyethylene (e.g., polyethylene terephthalate, polyethylene naphthalate), polyethersulfone, polyimide, polyamide (e.g., nylon), polystyrene, polyvinyl alcohol, ethylene-vinyl alcohol copolymer, fluororesin, vinyl chloride, polyolefin (e.g., polyethylene, polypropylene), cellulose, polyvinylidene chloride, aramid, polyphenylene sulfide, polyurethane, polycarbonate, polyarylate, polynorbornene, epoxy resin, etc.; paper materials; composite materials in which metals such as stainless steel, titanium, and aluminum are coated with resin, etc. are included. The substrate is preferably made of glass or a film.

[0024] The shape of the substrate may be, for example, a plate, a film, a sheet, etc. When light is taken in from the substrate side, it is preferable to use a substrate having high light transmittance.

[0025] <Lower electrode layer> The lower electrode layer is made of a conductive material, such as metals and alloys thereof, such as aluminum (Al), gold (Au), platinum (Pt), iridium (Ir), ruthenium (Ru), titanium (Ti), molybdenum (Mo), tantalum (Ta), copper (Cu), and silver (Ag), and conductive metal oxides, such as nickel oxide, tin oxide, indium oxide, indium tin oxide (ITO), indium zirconium oxide (IZO), titanium oxide, indium oxide, and zinc oxide.

[0026] The lower electrode layer may be formed of only one material, or may be formed by combining two or more selected materials. The lower electrode layer may be an anode and the upper electrode layer may be a cathode, or the lower electrode layer may be a cathode and the upper electrode layer may be an anode. When light is taken in from the substrate side, the lower electrode layer is preferably made of a translucent conductive metal oxide such as ITO, zinc oxide, or tin oxide, and ITO is particularly preferred. The lower electrode layer is preferably a light-transmitting electrode layer.

[0027] The thickness of the lower electrode layer is not particularly limited, and is, for example, 30 nm or more, preferably 50 nm or more, and is, for example, 200 nm or less, preferably 150 nm or less.

[0028] The manufacturing method of the lower electrode layer is not particularly limited, and the layer can be formed by a deposition method such as vacuum deposition or sputtering, or a coating method such as a mist method, a spray method, a spin coating method, a dip coating method, a slot die coating method, a doctor blade method, a bar coating method, an inkjet method, a screen printing method, or a gravure printing method.

[0029] <Functional layer> The functional layer includes, for example, an electron transport layer, an active layer, and a hole transport layer. In this specification, the case where the functional layer includes an electron transport layer, an active layer, and a hole transport layer will be mainly described, but the present embodiment is not limited thereto. The functional layer may not include one or both of the electron transport layer and the hole transport layer. It may have an inverted structure in which an electron transport layer, an active layer, and a hole transport layer are stacked in this order on a lower electrode layer (cathode), or it may have a normal structure in which a hole transport layer, an active layer, and an electron transport layer are stacked in this order on a lower electrode layer (anode). The stacking order within the functional layer differs depending on whether the lower electrode layer plays the role of a cathode or an anode.

[0030] In the case of a forward structure, when sunlight hits the substrate side, excitons are generated in the active layer and separated into electrons and holes at the donor / acceptor interface, with the electrons being attracted to the electron transport layer and the holes being attracted to the hole transport layer. As a result, by connecting the lower electrode layer side as the anode and the upper electrode layer side as the cathode, electricity flows between the lower electrode layer side and the upper electrode layer side. The principle of the inverted structure is the same as that of the forward structure.

[0031] The functional layer has an upper surface and a side surface formed at the end of the functional layer. As described later, an upper electrode layer is provided on at least a part of the upper surface of the functional layer, while an upper electrode layer is also provided on at least a part of the side surface of the functional layer. The upper surface of the functional layer may be flat or curved, but is preferably flat, and is preferably a flat surface parallel to the surface of the substrate. In this specification, "parallel" refers to a surface that is inclined at 0 to 10 degrees with respect to the surface of the substrate. In addition, the side surface of the functional layer may be flat or curved, but is preferably flat. The electron transport layer, active layer, and hole transport layer will be described below.

[0032] (electron transport layer) The constituent material of the electron transport layer is preferably an electron transporting material that improves the efficiency of electron extraction, and may be either an organic compound or an inorganic compound, but is preferably an inorganic compound.

[0033] The inorganic compound constituting the electron transport layer is preferably a metal compound, for example, an alkali metal salt such as lithium, sodium, potassium, cesium, etc., and a metal oxide. The alkali metal salt is preferably a fluoride salt such as lithium fluoride, sodium fluoride, potassium fluoride, cesium fluoride, etc., and the metal oxide is preferably a metal oxide having n-type semiconductor properties such as titanium oxide (TiOx) and zinc oxide (ZnO). The organic compound constituting the electron transport layer is preferably a conductive organic compound, for example, polyethyleneimine ethoxylate, etc.

[0034] By using an electron transport layer containing an electron transport material, it is possible to increase the efficiency of electron injection into the cathode, prevent hole injection from the active layer, enhance the electron transport ability, and suppress deterioration of the active layer.

[0035] In addition, it is preferable to provide an electron transport layer between the active layer and the electrode layer serving as the cathode, and by providing the electron transport layer between the cathode and the active layer, it is possible to prevent the cathode from peeling off and to increase the efficiency of electron extraction from the active layer to the cathode. It is more preferable that the electron transport layer is in contact with at least one of the active layer and the electrode layer serving as the cathode, and it is even more preferable that the electron transport layer is in contact with the active layer and the electrode layer serving as the cathode. By providing such an electron transport layer, it is possible to obtain a photoelectric conversion element with high reliability and higher photoelectric conversion efficiency.

[0036] The thickness of the electron transport layer is not particularly limited, and is, for example, 20 nm or more, preferably 40 nm or more, and is, for example, 100 nm or less, preferably 70 nm or less.

[0037] The method for producing the electron transport layer is not particularly limited, and the layer can be formed by, for example, a deposition method such as vacuum deposition or sputtering, or a coating method such as a spray method, a mist method, a spin coating method, a dip coating method, a slot die coating method, a doctor blade method, a bar coating method, an inkjet method, a screen printing method, or a gravure printing method.

[0038] (active layer) The active layer is where photoelectric conversion takes place and contains a p-type semiconductor compound and an n-type semiconductor compound. When the photoelectric conversion element receives light, the light is absorbed by the active layer, electricity is generated at the interface between the p-type semiconductor compound and the n-type semiconductor compound, and the generated electricity is extracted from the cathode and anode.

[0039] As the p-type semiconductor compound and the n-type semiconductor compound, known compounds can be used. As the p-type semiconductor compound, for example, conjugated copolymer semiconductor compounds such as polythiophene, polyfluorene, polyphenylenevinylene, polythienylenevinylene, polyacetylene, polyaniline, etc.; copolymer semiconductor compounds such as oligothiophene substituted with alkyl groups or other substituents, etc. may be used as the p-type semiconductor compound. As such, the active layer may contain an organic semiconductor.

[0040] Examples of n-type semiconductor compounds include fullerene and its derivatives, octaazaporphyrin, and perfluoro compounds in which hydrogen atoms of p-type semiconductor compounds are replaced with fluorine atoms (e.g., perfluoropentacene and perfluorophthalocyanine). Examples of n-type semiconductor compounds include polymer compounds containing aromatic carboxylic anhydrides such as naphthalene tetracarboxylic anhydride, naphthalene tetracarboxylic diimide, perylene tetracarboxylic anhydride, and perylene tetracarboxylic diimide, and / or imides thereof as a skeleton. In this way, the active layer can contain an organic semiconductor.

[0041] Examples of the layer structure of the active layer include a thin film laminate structure in which a p-type semiconductor compound and an n-type semiconductor compound are laminated, and a bulk heterojunction structure having a layer in which a p-type semiconductor compound and an n-type semiconductor compound are mixed. The bulk heterojunction structure has a layer (i-layer) in which a p-type semiconductor compound and an n-type semiconductor compound are mixed. The i-layer has a structure in which a p-type semiconductor compound and an n-type semiconductor compound are phase-separated, and carrier separation occurs at the phase interface, and the generated carriers (holes and electrons) are transported to the electrode. From the viewpoint of improving the photoelectric conversion efficiency by obtaining a good phase-separated structure, the mass ratio of the p-type semiconductor compound to the n-type semiconductor compound in the i-layer (p-type semiconductor compound / n-type semiconductor compound) is preferably 0.5 or more, more preferably 1 or more, and also preferably 4 or less, more preferably 3 or less, and even more preferably 2 or less.

[0042] The active layer may contain an additive in addition to the p-type semiconductor compound and the n-type semiconductor compound. When the layer structure of the active layer is a bulk heterojunction structure, the phase separation structure of the p-type semiconductor compound and the n-type semiconductor compound in the active layer affects light absorption, generation and diffusion of excitons, exciton dissociation (carrier separation), carrier transport, etc. It is expected that good photoelectric conversion efficiency can be achieved by optimizing the phase separation structure. By containing an additive having high affinity with the p-type semiconductor compound and / or the n-type semiconductor compound in the active layer, the active layer can have a phase separation structure that is favorable in terms of photoelectric conversion efficiency.

[0043] Examples of additives include aliphatic hydrocarbon compounds having 8 to 20 carbon atoms and aromatic compounds having 8 to 20 carbon atoms. These aliphatic hydrocarbon compounds and aromatic compounds may have a substituent. Examples of the substituent that the aliphatic hydrocarbon compound may have include a halogen atom, a hydroxyl group, a mercapto group, a cyano group, an amino group, a carbamoyl group, a carbonyloxy group, a carboxyl group, a carbonyl group, an aromatic group, and the like. Examples of the substituent that the aromatic compound may have include a halogen atom, a hydroxyl group, a cyano group, an amino group, an amide group, a carbonyloxy group, a carboxyl group, a carbonyl group, an oxycarbonyl group, a silyl group, an alkenyl group, an alkynyl group, an alkoxy group, an aryloxy group, an alkylthio group, an arylthio group, an aromatic group, and the like. Specific examples of preferred additives include benzene which may have a substituent, naphthalene which may have a substituent, and octane which may have a substituent. As the substituent, a halogen atom is particularly preferred.

[0044] From the viewpoint of obtaining a photoelectric conversion element having higher photoelectric conversion efficiency, the active layer is preferably provided between the electron transport layer and the hole transport layer, more preferably in contact with at least one of the electron transport layer or the hole transport layer, and further preferably in contact with both the electron transport layer and the hole transport layer.

[0045] The thickness of the active layer is not particularly limited, and is, for example, 80 nm or more, preferably 100 nm or more, and is, for example, 400 nm or less, preferably 300 nm or less.

[0046] The manufacturing method of the active layer is not particularly limited, and the active layer can be formed by, for example, a deposition method such as vacuum deposition or sputtering, or a coating method such as a spray method, a mist method, a spin coating method, a dip coating method, a slot die coating method, a doctor blade method, a bar coating method, an inkjet method, a screen printing method, or a gravure printing method.

[0047] (Hole transport layer) The hole transport layer has a function of extracting holes from the active layer to the anode. The material of the hole transport layer is not particularly limited as long as it is a hole transport material that can improve the efficiency of hole extraction, and examples of such materials include conductive organic compounds and metal compounds.

[0048] Examples of the conductive organic compound constituting the hole transport layer include conductive polymers in which polythiophene, polypyrrole, polyacetylene, triphenylenediamine, polyaniline, etc. are doped with sulfonic acid and / or iodine, polythiophene derivatives having sulfonyl groups as substituents, and arylamines. Examples of the metal compound constituting the hole transport layer include metal oxides having p-type semiconductor properties such as molybdenum trioxide, vanadium pentoxide, and nickel oxide, as well as metals such as gold, indium, silver, and palladium. The hole transport layer may be formed from a p-type semiconductor compound. Among these, the material constituting the hole transport layer is preferably a conductive polymer doped with sulfonic acid, more preferably poly(3,4-ethylenedioxythiophene)poly(styrenesulfonic acid) (PEDOT:PSS) in which a polythiophene derivative is doped with polystyrenesulfonic acid, and more preferably a metal oxide such as molybdenum oxide and vanadium oxide.

[0049] The hole transport layer is preferably provided between the active layer and the electrode layer serving as the anode, and by providing the hole transport layer between the anode and the active layer, it is possible to prevent the anode from peeling off and to increase the efficiency of hole extraction from the active layer to the anode. It is more preferable that the hole transport layer is in contact with at least one of the active layer or the electrode layer serving as the anode, and it is even more preferable that the hole transport layer is in contact with the active layer and the electrode layer serving as the anode. By providing such a hole transport layer, a photoelectric conversion element with high reliability and higher photoelectric conversion efficiency can be obtained.

[0050] The thickness of the hole transport layer is not particularly limited, and is, for example, 5 nm or more, preferably 10 nm or more, and is, for example, 200 nm or less, preferably 100 nm or less.

[0051] The method for producing the hole transport layer is not particularly limited, and the layer can be formed by, for example, a deposition method such as vacuum deposition or sputtering, or a coating method such as a spray method, a mist method, a spin coating method, a dip coating method, a slot die coating method, a doctor blade method, a bar coating method, an inkjet method, a screen printing method, or a gravure printing method.

[0052] <Top electrode layer> The upper electrode layer is made of a conductive material. The upper electrode layer may be made of the same material as the lower electrode layer, and the upper electrode layer contains a metal, preferably silver, gold, copper, or platinum, more preferably silver. The upper electrode layer may be made of only one material, or may be made of a combination of two or more selected materials.

[0053] The thickness of the upper electrode layer is not particularly limited, and is, for example, 50 nm or more, preferably 80 nm or more, and is, for example, 300 nm or less, preferably 200 nm or less.

[0054] The method for producing the upper electrode layer is not particularly limited, and examples thereof include printing methods such as vacuum deposition, inkjet printing, flexographic printing, gravure printing, screen printing, pad printing, and lithography, as well as dip, spray, and bar coating methods. For example, by adopting a printing method, it is easy to separate the coated and non-coated parts. In addition, it is easy to print large areas, thin lines, and complex shapes. Among the printing methods, the screen printing method is preferable because it can use a conductive paint with high viscosity and it is easy to adjust the coating thickness. When producing a photoelectric conversion element, the production method preferably includes a step of forming the upper electrode layer by vapor deposition of metal or application of a paste containing metal.

[0055] Although the substrate, lower electrode layer, functional layer (electron transport layer, active layer, hole transport layer), and upper electrode layer have been described above, the composition, thickness, and manufacturing method of these layers are not limited to the above description. In addition, the lower electrode layer, electron transport layer, active layer, and hole transport layer may be formed continuously on the outermost surface when each layer is formed, or may be formed discontinuously (for example, the lower electrode layer may be formed on the entire surface of the substrate, or may be formed only on a part of the surface of the substrate), so that it is sufficient that the lower electrode layer, electron transport layer, active layer, hole transport layer, and upper electrode layer are laminated on a part of the surface of the substrate.

[0056] <Barrier layer> By making the photoelectric conversion element have a structure sealed by a barrier layer, the intrusion of oxygen and moisture into the inside of the photoelectric conversion element can be reduced, and durability can be improved. As the material of the barrier layer, a material with low oxygen permeability and water vapor permeability is preferable, and a transparent material is also preferable. As a method for manufacturing such a barrier layer, for example, a method of forming a transparent inorganic film such as silicon oxide, aluminum oxide, aluminum-based compound, or silicon-based compound on a polymer film can be mentioned. As a method for forming a transparent inorganic film on a polymer film, a sol-gel method, a PVD method, an electron beam deposition method, a plasma CVD method, a reactive sputtering method, etc. can be mentioned. As the polymer film to be used, a PET film, a PEN film, a PES film, a nylon film, a polycarbonate film, etc. can be mentioned.

[0057] The photoelectric conversion element may also have a desiccant between the barrier layer and the upper electrode and / or the lower electrode. Moisture due to the heat of vaporization from the coating liquid may remain inside and cause deterioration, so the moisture can be removed by including a desiccant. Examples of desiccant include calcium oxide, barium oxide, magnesium oxide, magnesium sulfate, sodium sulfate, and calcium chloride, which are moisture-reactive, and silica gel, molecular sieve, zeolite, and activated carbon, which are moisture-adsorbing.

[0058] <Sealing material> When sealing with a barrier layer, there is no particular limitation on the sealing method or sealing material, and it can be appropriately selected according to the purpose, as long as the substrate and the barrier layer can be bonded together and the intrusion of excess moisture, oxygen, etc. from the external environment can be reduced. For example, in the case of a glass substrate, a method of sealing a glass can or a barrier film with an adhesive, or a method of bonding a barrier film by thermocompression bonding using a heat press or a laminator, etc. can be mentioned. Similarly, in the case of a film substrate, a method of sealing with an adhesive or thermocompression bonding can be mentioned, and sealing can be performed by directly bonding a barrier film to a substrate, or by sandwiching the substrate between barrier films. Examples of materials for the sealing material include epoxy resins, acrylic resins, silicon resins, and olefin resins.

[0059] <Other layers> In addition to the lower electrode layer, the electron transport layer, the active layer, the hole transport layer, the upper electrode layer, and the barrier layer, an antistatic layer, a slippery layer, a hard coat layer, a protective layer, an electromagnetic wave shielding layer, an ultraviolet absorbing layer, an infrared absorbing layer, a light reflective layer, and the like may be provided as necessary.

[0060] [Application] The photoelectric conversion element of the present invention can be used, for example, as a solar cell. The photoelectric conversion element of the present invention can also be used as a photodetector by providing the photoelectric conversion element with an output detection means for detecting an output signal output from the photoelectric conversion element.

[0061] [Example of photoelectric conversion element operation] In the photoelectric conversion element 11, for example, light is incident from the substrate side 12, and reaches the active layer 18 through the lower electrode layer 13, which is a transparent electrode. In the active layer 18, excitons are generated at the interface between the p-type semiconductor compound and the n-type semiconductor compound by the reaching light, and are separated into electrons and holes at the donor / acceptor interface, the electrons are attracted to the electron transport layer 17, and the holes are attracted to the hole transport layer 19, thereby generating electricity. The electricity generated in this manner is extracted from the lower electrode layer 13 and the upper electrode layer 15. In this manner, photoelectric conversion is performed. The principle is the same when the photoelectric conversion element 11 has a normal structure. EXAMPLES

[0062] The present invention will be described in detail below using examples, but the present invention is not limited to the following examples as long as it does not deviate from the gist of the invention. In the following, for ease of reference, the names of the components described with reference to Figure 1 may be used, but the reference symbols described with reference to Figure 1 may be omitted in the description. The conditions used in each of the following examples are shown in Table 1.

[0063] [Example 1] <Preparation of glass substrate with transparent electrodes> A 50 mm square glass substrate with an ITO film formed on one side of the glass substrate as a lower electrode layer was used, and the ITO coated surface was patterned by chemical etching as shown in Figure 2. The patterned glass substrate with an ITO film was ultrasonically cleaned using isopropyl alcohol, dried with clean dry air, and then UV / O3 treatment was performed.

[0064] <Deposition of electron transport layer> A ZnO nanoparticle dispersion (Avantama N-11) was dropped onto the ITO surface of the cleaned glass substrate with an ITO film, and the substrate was spin-coated at 1500 rpm for 45 seconds. The substrate was then heated on a hot plate at 140°C for 10 minutes.

[0065] <Deposition of active layer> A solution was prepared by mixing poly(3-hexylthiophene) (abbreviated as P3HT), a fullerene derivative (E100H manufactured by Frontier Carbon), and chlorobenzene in a ratio of 16 mg:16 mg:1 mL. This solution was dropped onto the substrate with the ZnO film formed above, and coated by spin coating at 1000 rpm for 45 seconds. The coated substrate was heated on a hot plate at 140°C for 10 minutes.

[0066] <Deposition of the hole transport layer> PEDOT:PSS (purchased from Ossila, HTL solar) was dropped onto the substrate after the active layer was formed, and spin-coated at 1000 rpm for 50 s. The substrate immediately after coating was heated on a hot plate at 100°C for 10 min. Excessive portions of the film laminated on the entire surface of the substrate were wiped off, and then mechanical scribing was performed to expose the ITO at the scribed lines, as shown in Figure 3.

[0067] <Deposition of the upper electrode layer> The substrate on which the hole transport layer was formed was set in a vacuum deposition apparatus, and an Ag electrode was deposited in the pattern shown in FIG.

[0068] <Sealing with a barrier layer> A getter agent was attached to the inside of a glass can for sealing. Using the glass can with the getter agent, the photoelectric conversion element obtained above was sealed with an epoxy adhesive (High Super 5 made by Cemedine) as shown in Figure 5. An organic thin-film solar cell was produced from the laminate obtained in this way.

[0069] [Example 2] <Preparation of glass substrate with transparent electrodes> The same treatment as in Example 1 was carried out.

[0070] <Deposition of electron transport layer> The same treatment as in Example 1 was carried out except that a ZnO nanoparticle dispersion liquid (Avantama N-11) was dropped and applied with a bar coater under conditions of 60° C. and 0.5 m / min.

[0071] <Deposition of active layer> A solution of P3HT, fullerene derivative (E100H manufactured by Frontier Carbon), and chlorobenzene mixed in a ratio of 16 mg:16 mg:1 mL was dropped onto the substrate after the ZnO film was formed as described above, and the same treatment as in Example 1 was carried out except that the solution was applied with a bar coater under conditions of 60°C and 0.5 m / min.

[0072] <Deposition of the hole transport layer> A solution was prepared by adding 5 wt% ethylene glycol to PEDOT:PSS (purchased from Ossila, HTL solar). This solution was dropped onto the substrate after the active layer was formed, and the same treatment as in Example 1 was carried out except that the solution was applied with a bar coater at 60°C and 1 m / min.

[0073] <Deposition of the upper electrode layer> The same process as in Example 1 was carried out, except that the electrode was formed from a conductive paste instead of vapor deposition of an Ag electrode. In forming the electrode from the conductive paste, a silver paste (DW-250H-28 manufactured by Toyobo) was screen-printed and heated at 90°C for 10 minutes to form an electrode.

[0074] <Sealing with a barrier layer> The same treatment as in Example 1 was carried out.

[0075] [Example 3] <Preparation of glass substrate with transparent electrodes> The same treatment as in Example 1 was carried out.

[0076] <Deposition of electron transport layer> The same treatment as in Example 1 was carried out, except that N-10 manufactured by Avantama was used instead of N-11 as the ZnO nanoparticle dispersion liquid to be used.

[0077] <Deposition of active layer> PM6 PBDB-T―2F (purchased from Ossila), Y6 BTP-4F (purchased from Ossila), and chloroform were mixed in a ratio of 8.4mg:8.4mg:1mL, and 3vol% of DIO was added to the chloroform as an additive to prepare a solution. This solution was dropped onto the substrate with the ZnO film formed above, and coated by spin coating at 1000rpm for 45s. The coated substrate was heated on a hot plate at 100℃ for 10min.

[0078] <Deposition of the hole transport layer> The same treatment as in Example 2 was carried out.

[0079] <Deposition of the upper electrode layer> The same treatment as in Example 2 was carried out.

[0080] <Sealing with a barrier layer> An aluminum oxide film was formed on a PET film by sputtering as a sealing film. Using the film, the photoelectric conversion element obtained above was sealed with a modified silicone adhesive (Super Multipurpose 2 manufactured by 3M) as shown in Figure 5. An organic thin-film solar cell was produced from the laminate obtained in this way.

[0081] [Example 4] The same processes as in Example 1 were carried out from the preparation of a glass substrate with a transparent electrode to the formation of an electron transport layer, an active layer, and a hole transport layer.

[0082] <Deposition of the upper electrode layer> The same process as in Example 1 was carried out, except that Au was used instead of Ag as the metal used for deposition.

[0083] <Sealing with a barrier layer> The same treatment as in Example 3 was carried out.

[0084] [Example 5] The preparation of the glass substrate with a transparent electrode, the deposition of the electron transport layer, and the deposition of the active layer were all performed in the same manner as in Example 1. The excess film on all four sides was wiped off, and then mechanical scribing was performed to expose the ITO at the scribe lines, as shown in Figure 6.

[0085] <Deposition of the hole transport layer> The substrate after the active layer formation obtained above was set in a vacuum deposition apparatus, and MoO3 was deposited in the pattern shown in Figure 6.

[0086] <Deposition of the upper electrode layer> The substrate on which the hole transport layer was formed was set in a vacuum deposition apparatus, and an Ag electrode was deposited in the pattern shown in FIG.

[0087] <Sealing with a barrier layer> The same treatment as in Example 3 was carried out.

[0088] [Example 6] <Preparation of glass substrate with transparent electrodes> PEDOT:PSS (purchased from Ossila, HTL solar) was dropped onto a glass substrate and coated with a bar coater at 60°C and 5m / min. The substrate immediately after coating was heated on a hot plate at 100°C for 10 minutes. In this way, a PEDOT:PSS film was formed on the glass substrate as a lower electrode layer, and a glass substrate with a PEDOT:PSS film was prepared.

[0089] The electron transport layer and the active layer were formed in the same manner as in Example 1.

[0090] The hole transport layer, the upper electrode layer, and the barrier layer were formed in the same manner as in Example 5.

[0091] [Example 7] <Preparation of PET substrate with transparent electrodes> A 50 mm square PET substrate with an ITO film was used, with an ITO film formed on one side of the PET substrate as the lower electrode layer, and the ITO coated surface was patterned by chemical etching as shown in Figure 2. The patterned PET substrate with an ITO film was ultrasonically cleaned using isopropyl alcohol, dried with clean dry air, and then UV / O3 treatment was performed.

[0092] <Deposition of electron transport layer> The same treatment as in Example 2 was carried out.

[0093] <Deposition of active layer> The same treatment as in Example 1 was carried out.

[0094] <Deposition of the hole transport layer> The same treatment as in Example 1 was carried out, except that AI4083 purchased from Ossila was used instead of HTL solar as the PEDOT:PSS used.

[0095] <Deposition of the upper electrode layer> The same treatment as in Example 1 was carried out to deposit an Ag electrode.

[0096] <Sealing with a barrier layer> An aluminum oxide film was formed on a PET film by sputtering as a sealing film. The photoelectric conversion element obtained above was sandwiched between two layers of the film, and sealing was performed using Aron Alpha EXTRA 2000 manufactured by Toagosei Co., Ltd., which is a cyanoacrylate adhesive.

[0097] <Extraction electrode> On the photoelectric conversion element already sealed with the barrier layer obtained above, an extraction electrode was further produced using copper tape as shown in Figure 8. An organic thin-film solar cell was produced from the laminate thus obtained.

[0098] [Table 1]

[0099] As described above, the present invention is not limited to the above-described embodiment, and in the implementation stage, the components can be modified without departing from the gist of the invention. In addition, various inventions can be formed by appropriately combining the multiple components disclosed in the above-described embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, different The components in the various embodiments may be combined as appropriate. [Explanation of symbols]

[0100] 11: Photoelectric conversion element 12: Circuit Board 13: Lower electrode layer 14: Functional Layer 15: Upper electrode layer 16: Barrier layer 17: Electron transport layer 18: Active layer 19: Hole transport layer 20: Encapsulating materials 21: ITO 22: Scribeline 23: Extraction electrode

Claims

1. A photoelectric conversion element comprising a substrate, a lower electrode layer, a functional layer, an upper electrode layer, and a barrier layer, wherein in at least a portion of the photoelectric conversion element, the substrate, the lower electrode layer, the functional layer, and the upper electrode layer are stacked in this order, the functional layer includes an active layer, and the stack including the substrate, the lower electrode layer, the functional layer, and the upper electrode layer is sealed by the barrier layer.

2. The photoelectric conversion element according to claim 1 , wherein the lower electrode layer is a light-transmitting electrode layer.

3. 3. The photoelectric conversion element according to claim 1, wherein the substrate is made of glass or a film.

4. The method for producing a photoelectric conversion element according to claim 1 , further comprising the step of forming the upper electrode layer by vapor deposition of a metal or by coating of a paste containing a metal.

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