JP2010114181A - Organic photoelectric conversion element, and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic photoelectric conversion element which has high photoelectric conversion efficiency and also has superior bending resistance when formed as a flexible type, and to provide a method of manufacturing the organic photoelectric conversion element which can greatly reduce the manufacturing cost by forming a transparent electrode and an organic layer by coating. <P>SOLUTION: The organic photoelectric conversion element 10 having a first electrode 12, the photoelectric conversion layer 14, and a second electrode 13 respectively on a transparent substrate 11 is provided with an electron block layer 15 formed of p-type metal oxide between the first electrode 12 and photoelectric conversion layer 14 by a wet method. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an organic photoelectric conversion element, and particularly relates to an organic photoelectric conversion element having excellent power generation efficiency by having an electron block layer, and excellent bending resistance in the case of a flexible type, and a method for producing the same. is there.

  Organic thin-film solar cells composed of organic photoelectric conversion elements are attracting attention as solar cells suitable for mass production because they can be formed by a coating method, and are actively studied in many research institutions. Organic thin-film solar cells have improved charge separation efficiency, which has been a problem, by a so-called bulk heterojunction structure in which an electron donor material and an electron acceptor material are mixed (see, for example, Patent Document 1).

  In recent years, the photoelectric conversion efficiency has been improved to the 5-6% range, and it can be said that the research for practical use has become more active. However, in organic photoelectric conversion elements for practical use in the future, development of organic photoelectric conversion elements that generate power with higher efficiency is desired.

  Organic thin-film solar cells can be manufactured not only by a vapor deposition process but also by using a coating process. When a flexible substrate is used, a conventional silicon solar cell can be realized by a so-called roll-to-roll process. It is expected to produce an inexpensive solar cell at a production cost that cannot be achieved. However, currently used materials such as organic semiconductors often require a desired functional layer to be formed in a vacuum or nitrogen atmosphere, and materials and methods for forming a functional layer under atmospheric pressure are practical. It has become one of the major issues toward the realization.

  As described above, although the charge separation efficiency is improved by using the bulk heterojunction structure, the actual situation is that the film thickness must be reduced because the charge mobility of the organic material is small. When the film thickness of the photoelectric conversion layer is reduced, the distance between the electrodes is shortened, so that leakage due to a short circuit is likely to occur, and reverse charge transport is likely to occur.

  So far, in the layer design of organic photoelectric conversion elements, a hole blocking layer that facilitates the selective passage of electrons between the second electrode serving as the cathode and the active layer serving as the photoelectric conversion layer has been introduced. Although it is known that the photoelectric conversion efficiency is improved (for example, see Patent Documents 2 and 3), although the hole block is effective, the improvement of the photoelectric conversion efficiency has not been sufficient.

  In addition, it is proposed to improve the photoelectric conversion efficiency by introducing an electron block layer that facilitates the selective passage of holes and makes it difficult for electrons to pass between the first electrode serving as the anode and the active layer serving as the photoelectric conversion layer. (For example, see Non-Patent Document 1) In this method, a NiO layer is formed as an electron blocking layer on the first electrode by a PLD (pulsed-laser deposition) method under a vacuum that excludes oxygen and moisture. In order to increase productivity, an electronic block layer that can be formed by a coating mold has been desired.

  On the other hand, as a transparent electrode excellent in productivity, a method of forming a transparent electrode by coating or printing using a coating solution in which a conductive polymer material typified by a π-conjugated polymer is dissolved or dispersed in an appropriate solvent Has also been proposed (see, for example, Patent Document 4). However, compared with a metal oxide transparent electrode such as ITO formed by a vacuum film forming method, there is a problem that conductivity is low and transparency is inferior.

Furthermore, a technique using conductive fibers such as carbon nanotubes (CNT) and metal nanowires is also disclosed, a part of the conductive fibers is fixed to the substrate with a transparent resin film, and a part of the conductive fibers is transparent resin. It has been proposed to form electrodes by projecting on the film surface (see, for example, Patent Document 5). However, since the electrode having such a structure has conductivity only in the portion where the conductive fiber protrudes on the surface, it does not have a function as a surface electrode, and in addition, the conductive fiber protrudes on the surface. Therefore, there has been a problem that it cannot be applied to the use of an organic photoelectric conversion element that requires smoothness of the electrode surface.
US Pat. No. 5,331,183 JP 2004-319705 A JP 2007-273939 A JP-A-6-273964 JP 2006-519712 A PNAS, February 26, 2008, Vol. 105, no. 8, p 2783-2787

  The object of the present invention is to provide an organic photoelectric conversion element having a high photoelectric conversion efficiency and an excellent bending resistance in the case of a flexible type, and at the same time greatly increasing the manufacturing cost by manufacturing a transparent electrode and an organic layer by coating. It is providing the manufacturing method of the organic photoelectric conversion element which can be reduced.

  The above object of the present invention can be achieved by the following configuration.

  1. An organic photoelectric conversion element having at least a first electrode, a photoelectric conversion layer, and a second electrode on a transparent substrate, respectively, comprising a p-type metal oxide formed by a wet method between the first electrode and the photoelectric conversion layer An organic photoelectric conversion element provided with an electron block layer.

  2. 2. The organic photoelectric conversion element as described in 1 above, wherein the electron blocking layer is made of amorphous NiO.

  3. 3. The organic photoelectric conversion element as described in 1 or 2 above, wherein the surface of the first electrode is composed of a conductive fiber and a transparent conductive material.

  4). 4. The organic photoelectric conversion element as described in 3 above, wherein the conductive fiber is at least one selected from the group consisting of metal nanowires and carbon nanotubes.

  5. 5. The organic photoelectric conversion element as described in 3 or 4 above, wherein the transparent conductive material is at least one selected from the group of conductive polymers and conductive metal oxide fine particles.

  6). An organic photoelectric conversion element manufacturing method comprising: forming an electron blocking layer by a wet method after forming a first electrode on a substrate at atmospheric pressure; and providing a photoelectric conversion layer and a second electrode thereon.

  7). 7. The method for producing an organic photoelectric conversion element as described in 6 above, wherein the electron blocking layer formed by the wet method is amorphous NiO.

  8). 8. The method for producing an organic photoelectric conversion element as described in 7 above, wherein the electron blocking layer made of amorphous NiO is formed by applying a Ni alkoxide solution and drying at room temperature.

  The present invention not only provides an organic photoelectric conversion element having a high photoelectric conversion efficiency and an excellent bending resistance when made into a flexible type, but also significantly increases the manufacturing cost by manufacturing a transparent electrode and an organic layer by coating. The manufacturing method of the organic photoelectric conversion element which can be reduced is provided.

  Hereinafter, the best mode for carrying out the present invention will be described in detail.

  As a result of earnest studies on the problem of improving the efficiency of a transparent conductive film that can be formed by a coating process and an organic photoelectric conversion element using the same, the present inventors have obtained a first electrode having a transparent conductive layer on a transparent substrate, In an organic photoelectric conversion element having a photoelectric conversion layer and a second electrode, an electron block layer made of a p-type metal oxide formed by a wet method is provided between the first electrode and the photoelectric conversion layer. As a result of the present invention, it has been found that an organic photoelectric conversion element having high photoelectric conversion efficiency can be produced by a simple process using a wet method.

  Hereinafter, these will be described in detail.

  FIG. 3 is a cross-sectional view showing a bulk heterojunction organic photoelectric conversion device of the present invention. In FIG. 3, the bulk heterojunction type organic photoelectric conversion element 10 includes a first electrode 12, an electron block layer 15, a bulk heterojunction layer photoelectric conversion layer 14, and a second electrode 13 sequentially stacked on one surface of a transparent substrate 11. ing.

  The transparent substrate 11 is a member that holds the first electrode 12, the electron block layer 15, the photoelectric conversion layer 14, and the second electrode 13 that are sequentially stacked. In the present embodiment, since the photoelectrically converted light is incident from the transparent substrate 11 side, the transparent substrate 11 can transmit the photoelectrically converted light, that is, with respect to the wavelength of the light to be photoelectrically converted. Transparent member. As the transparent substrate 11, for example, a glass substrate or a resin substrate is used. The transparent substrate 11 is not essential. For example, by forming the first electrode 12 and the photoelectric conversion layer 14 side second electrode 13 on the electronic block layer 15 side, the bulk heterojunction type organic photoelectric conversion element 10 is configured. Also good.

  The first electrode 12 needs to use the first electrode according to the present invention.

  The second electrode 13 can be made of metal (for example, gold, silver, copper, platinum, rhodium, ruthenium, aluminum, magnesium, indium, etc.), carbon, or the material of the first electrode 12, but is not limited thereto. Absent.

  In the bulk heterojunction organic photoelectric conversion element 10 shown in FIG. 3, the electron block layer 15 and the photoelectric conversion layer 14 are sandwiched between the first electrode 12 and the second electrode 13, but a pair of comb-like electrodes The back contact type organic photoelectric conversion element 10 may be configured such that is disposed on one side of the photoelectric conversion layer 14.

  The photoelectric conversion layer 14 is a layer that converts light energy into electrical energy, and includes a bulk heterojunction layer in which a p-type semiconductor material and an n-type semiconductor material are uniformly mixed. The p-type semiconductor material relatively functions as an electron donor (donor), and the n-type semiconductor material relatively functions as an electron acceptor (acceptor). Here, the electron donor and the electron acceptor are “an electron donor in which, when light is absorbed, electrons move from the electron donor to the electron acceptor to form a hole-electron pair (charge separation state)”. And an electron acceptor ”, which does not simply donate or accept electrons like an electrode, but donates or accepts electrons by a photoreaction.

(P-type semiconductor material)
Examples of the p-type semiconductor material used in the present invention include various condensed polycyclic aromatic compounds and conjugated compounds.

  As the condensed polycyclic aromatic compound, for example, anthracene, tetracene, pentacene, hexacene, heptacene, chrysene, picene, fluorene, pyrene, peropyrene, perylene, terylene, quaterylene, coronene, ovalene, sarkham anthracene, bisanthene, zestrene, heptazelene, Examples thereof include compounds such as pyranthrene, violanthene, isoviolanthene, cacobiphenyl, anthradithiophene, and derivatives and precursors thereof.

  Examples of the conjugated compound include polythiophene and its oligomer, polypyrrole and its oligomer, polyaniline, polyphenylene and its oligomer, polyphenylene vinylene and its oligomer, polythienylene vinylene and its oligomer, polyacetylene, polydiacetylene, tetrathiafulvalene compound, quinone Compounds, cyano compounds such as tetracyanoquinodimethane, fullerenes and derivatives or mixtures thereof.

  In particular, among polythiophene and oligomers thereof, thiophene hexamer α-seccithiophene α, ω-dihexyl-α-sexualthiophene, α, ω-dihexyl-α-kinkethiophene, α, ω-bis (3- An oligomer such as butoxypropyl) -α-sexithiophene can be preferably used.

  Furthermore, porphyrin, copper phthalocyanine, tetrathiafulvalene (TTF) -tetracyanoquinodimethane (TCNQ) complex, bisethylenetetrathiafulvalene (BEDTTTTF) -perchloric acid complex, BEDTTTF-iodine complex, TCNQ-iodine complex, etc. Organic molecular complexes, fullerenes such as C60, C70, C76, C78, C84, carbon nanotubes such as SWNT, dyes such as merocyanine dyes and hemicyanine dyes, σ-conjugated polymers such as polysilane, polygermane, and the like Organic and inorganic hybrid materials described in 2000-260999 can also be used.

  Among these π-conjugated materials, at least one selected from the group consisting of condensed polycyclic aromatic compounds such as pentacene, fullerenes, condensed ring tetracarboxylic acid diimides, metal phthalocyanines, and metal porphyrins is preferable.

  Examples of pentacenes include substituents described in International Publication No. 03/16599, International Publication No. 03/28125, US Pat. No. 6,690,029, Japanese Patent Application Laid-Open No. 2004-107216, and the like. A pentacene derivative described in U.S. Patent Application Publication No. 2003/136964 and the like; Amer. Chem. Soc. , Vol. 127. No. And substituted acenes described in 14.4986 and the like and derivatives thereof.

  Among these compounds, compounds that are highly soluble in an organic solvent to the extent that a solution process can be performed, can form a crystalline thin film after drying, and can achieve high mobility are preferable. Such compounds include those described in J. Org. Amer. Chem. Soc. , Vol. 123, p9482; Amer. Chem. Soc. , Vol. 130 (2008), no. No. 9, 2706 and the like, acene-based compounds substituted with a trialkylsilylethynyl group, a pentacene precursor described in U.S. Patent Application Publication No. 2003/136964, etc., and Japanese Patent Application Laid-Open No. 2007-224019 Examples include precursor type compounds (precursors) such as porphyrin precursors.

  Among these, the latter precursor type can be preferably used. This is because the precursor type is insolubilized after conversion, so when forming a hole transport layer, electron transport layer, hole block layer, electron block layer, etc. on the bulk hetero junction layer by a solution process, bulk hetero junction This is because the layer does not dissolve and the material constituting the layer and the material forming the bulk heterojunction layer are not mixed, and further improvement in efficiency and life can be achieved. .

(N-type semiconductor material)
Examples of n-type semiconductor materials used in the present invention include fullerene C60, fullerene C70, fullerene C76, fullerene C78, fullerene C84, fullerene C240, fullerene C540, mixed fullerene, fullerene nanotube, multi-wall nanotube, single-wall nanotube, nanohorn (Conical), octaazaporphyrin, p-type semiconductor perfluoro (perfluoropentacene, perfluorophthalocyanine, etc.), naphthalenetetracarboxylic anhydride, naphthalenetetracarboxylic diimide, perylenetetracarboxylic anhydride, perylenetetracarboxylic Examples thereof include aromatic carboxylic acid anhydrides such as acid diimides, imidized products thereof, and polymer compounds containing these structures as a skeleton.

  Examples of a method for forming a bulk heterojunction layer in which an electron acceptor and an electron donor are mixed include a vapor deposition method and a coating method (including a casting method and a spin coating method). Among these, a coating method is particularly preferable.

  The bulk heterojunction layer of the photoelectric conversion layer 14 is annealed at a predetermined temperature during the manufacturing process to be partially crystallized in order to improve the photoelectric conversion rate.

  In FIG. 3, light incident from the first electrode 12 through the transparent substrate 11 is absorbed by the electron acceptor or electron donor in the bulk heterojunction layer of the photoelectric conversion layer 14, and electrons are transferred from the electron donor to the electron acceptor. Move to form a hole-electron pair (charge separation state). When the generated electric charge has an internal electric field, for example, when the work functions of the first electrode 12 and the second electrode 13 are different, due to the potential difference between the first electrode 12 and the second electrode 13, electrons pass between the electron acceptors, Holes pass between electron donors and are carried to different electrodes, and photocurrent is detected.

  For example, when the work function of the first electrode 12 is larger than the work function of the second electrode 13, electrons are transported to the first electrode 12 and holes are transported to the second electrode 13. If the work function is reversed, electrons and holes are transported in the opposite direction. In addition, by applying a potential between the first electrode 12 and the second electrode 13, the transport direction of electrons and holes can be controlled.

  The photoelectric conversion layer 14 may be composed of a single layer in which an electron acceptor and an electron donor are uniformly mixed, but is composed of a plurality of layers in which the mixing ratio of the electron acceptor and the electron donor is changed. May be.

  Examples of a method for forming a bulk heterojunction layer in which an electron acceptor and an electron donor are mixed include a vapor deposition method and a coating method (including a casting method and a spin coating method). Among these, the coating method is preferable in order to increase the area of the interface where charges and electrons are separated from each other as described above and to produce a device having high photoelectric conversion efficiency. After application, it is preferable to perform heating in order to cause removal of residual solvent, moisture and gas, and chemical reaction of the semiconductor material as described above.

(Electronic block layer formed by wet method)
The organic photoelectric conversion element of the present invention is characterized in that an electron blocking layer made of a p-type metal oxide formed by a wet method is provided between the first electrode and the photoelectric conversion layer. The electron blocking layer according to the present invention has an electron blocking ability and a hole transport ability, and is characterized by being formed by a wet method.

  By providing the electron block layer formed by the wet method according to the present invention, the formation process becomes easier and the productivity is improved as compared with the NiO layer by the conventional LPD method, and a flexible substrate is used. It was found that the bending resistance in the case was improved.

  The electron blocking layer formed by the wet method according to the present invention is preferably formed by a sol-gel reaction using an organometallic compound made of a p-type metal oxide as a starting material, and more preferably amorphous NiO. .

  An organometallic compound is a compound in which a metal and an organic substance are covalently bonded, coordinated or ionically bonded, and examples thereof include metal alkoxides, metal acylates, metal chelates, organometallic salts, and halogen metal compounds. In the invention, metal alkoxides are preferably used from the viewpoints of reactivity and stability.

  The organometallic compound useful in the present invention is preferably a compound represented by the following general formula, but is not limited thereto.

[General Formula] MR ¹ _x R ² _y R ³ _z
In the present invention, it is necessary to be a starting material to be a p-type metal oxide. In the above general formula, M represents a metal (for example, Cr, Mn, Fe, Co, Ni, Cu, etc.), R ¹ is an alkyl group, R ² is an alkoxy group, R ³ is a group selected from a β-diketone coordination group, a β-ketocarboxylic acid ester coordination group, a β-ketocarboxylic acid coordination group, and a ketooxy group (ketooxy coordination group) When the valence of the metal M is m, x + y + z = m, x = 0 to m, or x = 0 to m−1, y = 0 to m, z = 0 to m, Both are 0 or a positive integer.

Examples of the alkyl group represented by R ¹ include a methyl group, an ethyl group, a propyl group, and a butyl group. Examples of the alkoxy group represented by R ² include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, and a 3,3,3-trifluoropropoxy group. Moreover, what substituted the hydrogen atom of the alkyl group by the fluorine atom may be used.

The group selected from the β-diketone coordination group, β-ketocarboxylic acid ester coordination group, β-ketocarboxylic acid coordination group and ketooxy group (ketooxy coordination group) represented by R ³ is β-diketone coordination group. Examples of the group include 2,4-pentanedione (also referred to as acetylacetone or acetoacetone), 1,1,1,5,5,5-hexamethyl-2,4-pentanedione, 2,2,6,6-tetra Methyl-3,5-heptanedione, 1,1,1-trifluoro-2,4-pentanedione, and the like. Examples of β-ketocarboxylic acid ester coordination groups include, for example, acetoacetic acid methyl ester, acetoacetic acid And ethyl ester, propyl acetoacetate, ethyl trimethylacetoacetate, methyl trifluoroacetoacetate and the like, β-ketocarboxylic acid Examples of the coordinating group include acetoacetic acid and trimethylacetoacetic acid, and examples of the ketooxy coordinating group include an acetooxy group (or acetoxy group), propionyloxy group, butyryloxy group, acryloyloxy group, and methacryloyloxy. Groups and the like.

  The number of carbon atoms of these groups is preferably 18 or less, including the above organometallic compounds. Further, as shown in the examples, it may be linear or branched, or a hydrogen atom substituted with a fluorine atom.

In the present invention, an organometallic compound having a low risk of explosion is preferable from the viewpoint of handling, and an organometallic compound having at least one oxygen in the molecule is preferable. As such, an organometallic compound containing at least one alkoxy group of R ² , or a β-diketone coordination group, β-ketocarboxylic acid ester coordination group, β-ketocarboxylic acid coordination group of R ³ and A metal compound having at least one group selected from a ketooxy group (ketooxy coordination group) is preferred.

  In the present invention, amorphous NiO formed by heat treatment or the like using nickel metal alkoxide, for example, nickel isopropoxide as a starting material is more preferable.

  Next, the solvent used for the sol-gel reaction will be described. The solvent mixes each component in the sol liquid uniformly to prepare the solid content of the composition according to the present invention, and at the same time, can be applied to various coating methods to improve the dispersion stability and storage stability of the composition. It is something to be made.

  These solvents are not particularly limited as long as they can fulfill the above purpose. Preferable examples of these solvents include water and organic solvents that are highly miscible with water.

  Examples of organic solvents include tetrahydrofuran, dimethoxyethane, formic acid, acetic acid, methyl acetate, alcohols (methanol, ethanol, n-propyl alcohol, iso-propyl alcohol, t-butyl alcohol), ethylene glycol, diethylene glycol, triethylene glycol , Ethylene glycol monobutyl ether, acetone, N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide and the like.

  In the use of an organometallic compound, a chelate ligand can be used for the stability of the solution. Examples of chelating ligands include diethanolamine, triethanolamine, monoethanolamine and the like.

  When heating the metal oxide starting material after coating, the heating temperature varies depending on the type of starting material used, the heating time, and the like, but can be performed in the range of 120 to 600 ° C. When the heating temperature is high, the heating time can be shortened to about 5 to 60 minutes.

  The bulk heterojunction organic photoelectric conversion element 10 includes a first electrode 12, an electron block layer 15, a bulk heterojunction photoelectric conversion layer 14, and a second electrode 13 sequentially stacked on the transparent substrate 11. However, the present invention is not limited to this. For example, other layers such as a hole transport layer, an electron transport layer, or a smoothing layer are provided between the first electrode 12 and the second electrode 13 and the photoelectric conversion layer 14. The bulk heterojunction organic photoelectric conversion element 10 may be configured. Among these, a hole transport layer is formed between the bulk heterojunction layer and the anode (usually the first electrode 12 side), and an electron transport layer is formed between the cathode (usually the second electrode 13 side). Thus, since it is possible to more efficiently extract charges generated in the bulk heterojunction layer, it is preferable to include these layers.

  In addition to the electron blocking layer according to the present invention, as the hole transport layer, there are PEDOT such as Stark Vuitec, trade name BaytronP, polyaniline and its doped material, triarylamine described in JP-A-5-271166, etc. System compounds can be used. A layer made of a single p-type semiconductor material used for the bulk heterojunction layer can also be used. The means for forming these layers may be either a vacuum deposition method or a solution coating method, but is preferably a solution coating method.

  As the electron transport layer, octaazaporphyrin, p-type semiconductor perfluoro (perfluoropentacene, perfluorophthalocyanine, etc.), naphthalene tetracarboxylic acid anhydride, naphthalene tetracarboxylic acid diimide, perylene tetracarboxylic acid anhydride, Use of n-type semiconductor materials such as perylenetetracarboxylic acid diimide, and n-type inorganic oxides such as titanium oxide, zinc oxide, and gallium oxide, and alkali metal compounds such as lithium fluoride, sodium fluoride, and cesium fluoride. it can.

  A layer made of a single n-type semiconductor material used for the bulk heterojunction layer can also be used. The means for forming these layers may be either a vacuum deposition method or a solution coating method, but is preferably a solution coating method.

  Moreover, it is preferable to seal by the well-known method so that the produced organic photoelectric conversion element 10 does not deteriorate with oxygen, moisture, etc. in the environment. For example, a method of sealing a cap made of aluminum or glass by bonding with an adhesive, a plastic film on which a gas barrier layer such as aluminum, silicon oxide, or aluminum oxide is formed and the organic photoelectric conversion element top 10 with an adhesive A method of bonding, a method of spin-coating an organic polymer material with high gas barrier properties (polyvinyl alcohol, etc.), a method of directly depositing an inorganic thin film with high gas barrier properties (silicon oxide, aluminum oxide, etc.), and a combination of these The method of laminating can be mentioned.

(Transparent substrate)
The transparent substrate used for the first electrode according to the present invention is not particularly limited as long as it has high light transmittance. For example, a glass substrate, a resin substrate, a resin film, and the like are preferable in terms of excellent hardness as a base material and ease of formation of a conductive layer on the surface. From the viewpoint, it is preferable to use a transparent resin film.

  There is no restriction | limiting in particular in the transparent resin film which can be preferably used as a transparent base material by this invention, About the material, a shape, a structure, thickness, etc., it can select suitably from well-known things.

  For example, polyester resin films such as polyethylene terephthalate (PET), polyethylene naphthalate, modified polyester, polyethylene (PE) resin films, polypropylene (PP) resin films, polystyrene resin films, polyolefin resin films such as cyclic olefin resins, Vinyl resin films such as polyvinyl chloride and polyvinylidene chloride, polyether ether ketone (PEEK) resin film, polysulfone (PSF) resin film, polyether sulfone (PES) resin film, polycarbonate (PC) resin film, polyamide resin A film, a polyimide resin film, an acrylic resin film, a triacetyl cellulose (TAC) resin film, and the like can be given. If the resin film transmittance of 80% or more in nm), can be preferably applied to a transparent resin film according to the present invention.

  Among them, from the viewpoint of transparency, heat resistance, ease of handling, strength and cost, it is preferably a biaxially stretched polyethylene terephthalate film, a biaxially stretched polyethylene naphthalate film, a polyethersulfone film, or a polycarbonate film. More preferred are a stretched polyethylene terephthalate film and a biaxially stretched polyethylene naphthalate film.

  The transparent substrate used in the present invention can be subjected to a surface treatment or an easy-adhesion layer in order to ensure the wettability and adhesion of the coating solution. A conventionally well-known technique can be used about a surface treatment or an easily bonding layer. For example, the surface treatment includes surface activation treatment such as corona discharge treatment, flame treatment, ultraviolet treatment, high frequency treatment, glow discharge treatment, active plasma treatment, and laser treatment.

  Examples of the easy adhesion layer include polyester, polyamide, polyurethane, vinyl copolymer, butadiene copolymer, acrylic copolymer, vinylidene copolymer, and epoxy copolymer. The easy adhesion layer may be a single layer, but may be composed of two or more layers in order to improve adhesion. In addition, a barrier coat layer may be formed in advance on the transparent substrate, or a hard coat layer may be formed in advance on the side opposite to the provision of the light-transmitting first electrode.

(First electrode)
The 1st electrode which has a transparent conductive layer concerning the present invention serves as an anode in an organic photoelectric conversion element.

  FIG. 1 shows a structural schematic diagram of a first electrode having a transparent conductive layer according to the present invention. The first electrode 4 according to the present invention includes at least the metal nanowire 1 on the transparent base material 5, and has a first transparent resin 3 that is retained and bound to the side close to the transparent base material as a preferred configuration. And it has the 2nd transparent resin component containing part or the transparent inorganic component containing part 2 in the side far from a transparent base material.

  In the example of FIG. 1, the transparent resin component-containing portion 2 exists in the gap on the electrode surface side of the three-dimensional mesh structure (conductive network structure) formed by the metal nanowires 1. The metal nanowire 1 can function as an auxiliary electrode of the transparent inorganic component-containing part 2 at the same time as constituting the surface of the electrode together with the transparent resin component-containing part 2. Further, the first transparent resin 3 exists between the gap between the transparent base material 5 side of the three-dimensional mesh structure of the metal nanowire 1 and the transparent base material 5, and the metal nanowire 1 -containing portion is used as the transparent base material 5. It is fixed.

  In the example of FIG. 2, the transparent inorganic component-containing portion 2 exists so as to include a three-dimensional mesh structure formed by the metal nanowires 1. The metal nanowire 1 can function as an auxiliary electrode of the transparent inorganic component-containing unit 2 at the same time that it forms the surface of the electrode together with the transparent inorganic component-containing unit 2. Moreover, the 1st transparent resin 3 exists between the transparent inorganic component containing part 2 and the transparent base material 5, and the metal nanowire 1 containing part is fixed to the transparent base material 5.

  In the first electrode 4 according to the present invention, the total light transmittance is preferably 60% or more, more preferably 70% or more, and particularly preferably 80% or more. The total light transmittance can be measured according to a known method using a spectrophotometer or the like.

  The electrical resistance value of the first electrode according to the present invention is preferably 50Ω / □ or less, more preferably 10Ω / □ or less, and particularly preferably 3Ω / □ or less as the surface resistivity. preferable. If it exceeds 50Ω / □, the photoelectric conversion efficiency may be inferior in an organic photoelectric conversion element having a large light receiving area. The surface resistivity can be measured in accordance with, for example, JIS K 7194: 1994 (resistivity test method using a conductive plastic four-probe method), and can be easily performed using a commercially available surface resistivity meter. Can be measured.

  There is no restriction | limiting in particular in the thickness of the 1st electrode which concerns on this invention, Although it can select suitably according to the objective, Generally it is preferable that it is 10 micrometers or less, and transparency and a softness | flexibility improve, so that thickness becomes thin. Therefore, it is more preferable.

(Metal nanowires)
As the conductive fiber according to the present invention, an organic fiber or inorganic fiber coated with a metal, a conductive metal oxide fiber, a metal nanowire, a carbon fiber, a carbon nanotube, or the like can be used, and a metal nanowire is preferable.

  In general, a metal nanowire refers to a linear structure having a metal element as a main component. In particular, the metal nanowire in the present invention means a linear structure having a diameter of nm size.

  The metal nanowire according to the present invention preferably has an average length of 3 μm or more in order to form a long conductive path with one metal nanowire and to exhibit appropriate light scattering properties. 3-500 micrometers is preferable and it is especially preferable that it is 3-300 micrometers. In addition, the relative standard deviation of the length is preferably 40% or less. In addition, the average diameter is preferably small from the viewpoint of transparency, while it is preferably large from the viewpoint of conductivity. In this invention, 10-300 nm is preferable as an average diameter of metal nanowire, and it is more preferable that it is 30-200 nm. In addition, the relative standard deviation of the diameter is preferably 20% or less.

  There is no restriction | limiting in particular as a metal composition of the metal nanowire which concerns on this invention, Although it can comprise from the 1 type or several metal of a noble metal element and a base metal element, noble metals (for example, gold, platinum, silver, palladium, rhodium, (Iridium, ruthenium, osmium, etc.) and at least one metal belonging to the group consisting of iron, cobalt, copper, and tin is preferable, and at least silver is more preferable from the viewpoint of conductivity. In order to achieve both conductivity and stability (sulfurization and oxidation resistance of metal nanowires and migration resistance), it is also preferable to include silver and at least one metal belonging to a noble metal other than silver.

  When the metal nanowire according to the present invention includes two or more kinds of metal elements, for example, the metal composition may be different between the inside and the surface of the metal nanowire, or the entire metal nanowire has the same metal composition. May be.

  In the present invention, the means for producing the metal nanowire is not particularly limited, and for example, known means such as a liquid phase method and a gas phase method can be used. Moreover, there is no restriction | limiting in particular in a specific manufacturing method, A well-known manufacturing method can be used.

  For example, as a method for producing Ag nanowires, Adv. Mater. , 2002, 14, 833-837; Chem. Mater. , 2002, 14, 4736-4745, etc. As a method for producing Co nanowires, a method for producing Au nanowires is disclosed in JP 2006-233252A, and a method for producing Cu nanowires is disclosed in JP 2002-266007 A, etc. Reference can be made to Japanese Unexamined Patent Publication No. 2004-149871. In particular, Adv. Mater. And Chem. Mater. The method for producing Ag nanowires reported in (1) can be easily produced in an aqueous system, and since the conductivity of silver is the highest among metals, it is preferable as the method for producing metal nanowires according to the present invention. Can be applied.

  In the present invention, the metal nanowires come into contact with each other to form a three-dimensional conductive network, exhibiting high conductivity, and allowing light to pass through the window of the conductive network where no metal nanowire exists. In addition, the power generation from the organic power generation layer portion can be efficiently performed by the scattering effect of the metal nanowires. In the first electrode, if the metal nanowire is installed on the side close to the organic power generation layer portion, this scattering effect can be used more effectively, which is a more preferable embodiment.

(Configuration other than the metal nanowire of the first electrode)
In the present invention, by including the metal nanowire in the first electrode, in addition to the effect of scattering the light of the metal nanowire, the metal nanowire has high conductivity, so other conductivity can be obtained without degrading the conductivity. It becomes possible to use a resin having a relatively low refractive index in combination, which makes it possible to keep the refractive index of the first electrode lower than that of the power generation layer portion, and the base material, the first electrode, and the power generation layer portion. Reflection at each interface is suppressed, and light can effectively reach the power generation layer portion. In order to effectively exhibit this effect, it is preferable that the average refractive index of the first electrode is lower than the average refractive index of the organic power generation layer portion.

  The first electrode according to the present invention contains metal nanowires, but is preferably used in combination with some transparent resin or transparent inorganic material in order to hold the metal nanowires, and the material is used so as to satisfy the above-described refractive index relationship. What is necessary is just to select suitably. Such materials are not particularly limited, but for example, polyester resins, polystyrene resins, acrylic resins, polyurethane resins, acrylic urethane resins, polycarbonate resins, cellulose resins, butyral resins, etc. may be used alone or in combination. Can be used. Further, it may be a UV curable resin.

  As a more preferred embodiment, when the first electrode is divided by a half film thickness, the average haze value of the portion on the side different from the organic power generation layer portion is EH1, and the average haze value of the portion near the transparent substrate is EH2. It is preferable that EH1 <EH2. By doing so, the optical path length can be extended more effectively by scattering of incident light, and the scattering effect of the metal nanowire according to the present invention can be maximized.

  The haze value of the first electrode can be changed depending on the content and diameter of the metal nanowire, the content and particle diameter of the conductive metal oxide in the later operation, and the like.

  The first electrode contains at least a first transparent resin component (for example, the aforementioned resin) and a second transparent resin component having a refractive index higher than that of the transparent resin component in addition to the metal nanowire, The metal nanowire is configured so that the first transparent resin component is included in a large amount on the side close to the organic power generation layer part, and the first electrode is added to the metal nanowire at least in the first side. 1 transparent resin component and a transparent inorganic component having a refractive index higher than that of the transparent resin component, the transparent inorganic component and the metal nanowire being closer to the organic power generation layer portion, and the first resin component being a transparent substrate It is also a preferred embodiment of the present invention that a large number are included on the near side.

Furthermore, it is a more preferable embodiment of the present invention that the second transparent resin component is a conductive polymer and the transparent inorganic component is a transparent conductive metal oxide. By using a conductive polymer or a transparent conductive metal oxide, it is possible to energize even a minute region of a window portion where no metal nanowire exists, and to function as a complete surface electrode. Thus, in order to work as a complete surface electrode, the surface resistance of the conductive material alone needs to be smaller than 10 ¹⁰ Ω / □, and more preferably 10 ⁸ Ω / □ or less.

  Examples of such conductive polymers include polypyrrole, polyaniline, polythiophene, polythienylene vinylene, polyazulene, polyisothianaphthene, polycarbazole, polyacetylene, polyphenylene, polyphenylene vinylene, polyacene, polyphenylacetylene, polydiacetylene, and polynaphthalene. The compound etc. which are chosen from the group which consists of each derivative can be mentioned.

As the transparent conductive metal _{oxide, ZrO 2, CeO 2, ZnO} , TiO 2, SnO 2, Al 2 O 3, In 2 O 3, SiO 2, MgO, BaO, MoO 2, V 2 O 5 , etc. Metal oxide fine particles, composite oxide fine particles of these, composite metal oxide fine particles doped with different atoms, or metal oxide sols of these, and in particular, from the viewpoint of conductivity and transparency, tin It is preferable to use fine particles or sols such as zinc-doped indium oxide (ITO, IZO), aluminum or gallium-doped zinc oxide (AZO, GZO), fluorine or antimony-doped tin oxide (FTO, ATO). it can. These may be used alone or in combination with other resin components.

  In addition, if fine particles are contained in the first transparent resin component according to the present invention, it becomes possible to improve light uptake at the interface between the first electrode and the transparent substrate, which is a more preferred embodiment of the present invention. The particle diameter is preferably 0.05 μm to 5 μm, more preferably 0.05 μm to 2 μm. If it is less than 0.05 μm, the effect of scattering and refracting light is small, and if it is larger than 5 μm, smoothness becomes a problem.

  The refractive index of the particles is preferably from 1.1 to 2.0, and more preferably from 1.3 to 1.7. Within this range, there are few components that scatter light back, and light capture efficiency can be improved while suppressing a decrease in transmittance. Examples of such fine particles include cross-linked acrylic particles, cross-linked styrene-based fine particles, silica-based fine particles, melamine / formaldehyde condensate-based fine particles, and composite fine particles of such materials. Such fine particles may be used alone or in combination.

(Formation method of the first electrode)
The method for forming the first electrode is not particularly limited, but if all the agents are formed in a coating system, a so-called roll-to-roll process can be used, and continuous at a higher speed with simpler equipment than when using a vacuum process. Production is more preferable.

  In addition, by forming a layer containing metal nanowires and a conductive polymer or a transparent conductive metal oxide on the release surface of a smooth release substrate, these layers are transferred onto the transparent substrate. It is preferable to use a method of forming the first electrode. In the organic photoelectric conversion element, flatness of the first electrode is required. By using this method, high smoothing can be performed easily and stably. Further, this method makes it possible to install a layer including a layer containing a metal nanowire, a conductive polymer having a relatively high refractive index, or a transparent conductive metal oxide on the side closer to the organic power generation layer portion of the first electrode. .

  Preferred examples of the releasable substrate used in the first electrode manufacturing method using this transfer process include a resin substrate and a resin film. There is no restriction | limiting in particular in this resin, It can select suitably from well-known things, For example, synthesis | combination, such as a polyethylene terephthalate resin, a vinyl chloride resin, an acrylic resin, a polycarbonate resin, a polyimide resin, a polyethylene resin, a polypropylene resin A substrate or film composed of a single layer or multiple layers of resin is preferably used. Furthermore, a glass substrate or a metal substrate can also be used. Further, the surface (release surface) of the releasable substrate may be subjected to a surface treatment by applying a release agent such as silicone resin, fluororesin, or wax as necessary.

  Since the surface of the releasable substrate affects the smoothness of the surface after the transparent conductive layer is transferred, it is desirable that the surface of the releasable substrate be highly smooth. Specifically, Ry ≦ 50 nm is preferable, and Ry ≦ 40 nm. More preferably, Ry ≦ 30 nm is still more preferable. Further, Ra ≦ 5 nm is preferable, Ra ≦ 3 nm is more preferable, and Ra ≦ 1 nm is still more preferable.

  In the present invention, Ry and Ra representing the smoothness of the surface of the transparent conductive layer mean Ry = maximum height (the difference in height between the top and bottom of the surface) and Ra = arithmetic mean roughness, JIS B601. It is a value according to the surface roughness specified in (1994). The first electrode according to the present invention is characterized in that the surface smoothness of the transparent conductive layer is Ry ≦ 50 nm. In addition, the smoothness of the surface of the transparent conductive layer is preferably Ra ≦ 5 nm. In the present invention, for the measurement of Ry and Ra, a commercially available atomic force microscope (AFM) can be used. For example, it can be measured by the following method.

  Using the Seiko Instruments SPI3800N probe station and SPA400 multifunctional unit as the AFM, set the sample cut to about 1 cm square size on a horizontal sample stage on the piezo scanner, and approach the cantilever to the sample surface. When the atomic force is reached, scanning is performed in the XY directions, and the unevenness of the sample at that time is captured by the displacement of the piezo in the Z direction. A piezo scanner that can scan XY 150 μm and Z 5 μm is used. The cantilever is a silicon cantilever SI-DF20 manufactured by Seiko Instruments Inc., which has a resonance frequency of 120 to 150 kHz and a spring constant of 12 to 20 N / m, and is measured in a DFM mode (Dynamic Force Mode). A measurement area of 80 × 80 μm is measured at a scanning frequency of 0.1 Hz.

  There is no particular limitation on the method for forming a layer containing metal nanowires, conductive polymer, or transparent conductive metal oxide on the release surface of the releasable substrate, but improvement in productivity, smoothness, uniformity, etc. From the viewpoint of improving the electrode quality and reducing the environmental load, it is preferable to use a liquid phase film forming method such as a coating method or a printing method.

  Application methods include roll coating, bar coating, dip coating, spin coating, casting, die coating, blade coating, bar coating, gravure coating, curtain coating, spray coating, and doctor coating. Etc. can be used.

  As the printing method, a letterpress (letter) printing method, a stencil (screen) printing method, a lithographic (offset) printing method, an intaglio (gravure) printing method, a spray printing method, an ink jet printing method, and the like can be used. In addition, as necessary, physical surface treatment such as corona discharge treatment or plasma discharge treatment can be applied to the surface of the releasable substrate as a preliminary treatment for improving the adhesion and coating properties.

  As an adhesive when transferring onto a transparent substrate, the first transparent resin component according to the present invention may have this function. For example, the above-described transparent resin may be used, and the adhesive is releasable. It may be provided on the substrate side or may be provided on the transparent substrate side. The adhesive is not particularly limited as long as it is transparent in the visible region and has a transfer capability. As long as it is transparent, a curable resin or a thermoplastic resin may be used. Examples of curable resins include thermosetting resins, ultraviolet curable resins, and electron beam curable resins. Among these curable resins, the equipment for resin curing is simple and excellent in workability. It is preferable to use an ultraviolet curable resin.

  The ultraviolet curable resin is a resin that is cured through a crosslinking reaction or the like by ultraviolet irradiation, and a component containing a monomer having an ethylenically unsaturated double bond is preferably used. For example, acrylic urethane type resin, polyester acrylate type resin, epoxy acrylate type resin, polyol acrylate type resin and the like can be mentioned. In the present invention, it is preferable that an acrylic or acrylic urethane-based ultraviolet curable resin is a main component as a binder.

  Acrylic urethane resins generally include 2-hydroxyethyl acrylate and 2-hydroxyethyl methacrylate (hereinafter referred to as “acrylate” including methacrylate) in products obtained by reacting a polyester polyol with an isocyanate monomer or a prepolymer. It can be easily obtained by reacting an acrylate monomer having a hydroxyl group such as 2-hydroxypropyl acrylate. For example, those described in JP-A-59-151110 can be used. For example, a mixture of 100 parts Unidic 17-806 (Dainippon Ink Co., Ltd.) and 1 part Coronate L (Nihon Polyurethane Co., Ltd.) is preferably used.

  Examples of UV curable polyester acrylate resins include those which are easily formed when 2-hydroxyethyl acrylate and 2-hydroxy acrylate monomers are generally reacted with polyester polyols. JP-A-59-151112 Those described in the publication can be used.

  Specific examples of the ultraviolet curable epoxy acrylate resin include an epoxy acrylate as an oligomer, a reactive diluent and a photoreaction initiator added to the oligomer, and a reaction. Those described in Japanese Patent No. 105738 can be used.

  Specific examples of UV curable polyol acrylate resins include trimethylolpropane triacrylate, ditrimethylolpropane tetraacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, alkyl-modified dipentaerythritol pentaacrylate, etc. Can be mentioned.

  Examples of the resin monomer may include general monomers such as methyl acrylate, ethyl acrylate, butyl acrylate, benzyl acrylate, cyclohexyl acrylate, vinyl acetate, and styrene as monomers having one unsaturated double bond. In addition, as monomers having two or more unsaturated double bonds, ethylene glycol diacrylate, propylene glycol diacrylate, divinylbenzene, 1,4-cyclohexane diacrylate, 1,4-cyclohexyldimethyl adiacrylate, the above-mentioned trimethylol Examples thereof include propane triacrylate and pentaerythritol tetraacryl ester.

  Among these, 1,4-cyclohexanediacrylate, pentaerythritol tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, trimethylolpropane (meth) acrylate, trimethylolethane (meth) acrylate as the main component of the binder , An acrylic selected from dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1,2,3-cyclohexanetetramethacrylate, polyurethane polyacrylate, polyester polyacrylate A system active ray curable resin is preferred.

  Specific examples of the photoinitiator of these ultraviolet curable resins include benzoin and its derivatives, acetophenone, benzophenone, hydroxybenzophenone, Michler's ketone, α-amyloxime ester, thioxanthone, and derivatives thereof. You may use with a photosensitizer. The photoinitiator can also be used as a photosensitizer.

  In addition, when using an epoxy acrylate photoinitiator, a sensitizer such as n-butylamine, triethylamine, or tri-n-butylphosphine can be used. The photoreaction initiator or photosensitizer used in the ultraviolet curable resin composition is 0.1 to 15 parts by weight, preferably 1 to 10 parts by weight, based on 100 parts by weight of the composition.

  The transparent conductive layer is made transparent by bonding (bonding) the release substrate formed with the transparent conductive layer and the transparent base material, curing the adhesive by irradiating ultraviolet rays and the like, and then peeling the release substrate. It can be transferred to the substrate side. Here, the bonding method is not particularly limited and can be performed by a sheet press, a roll press or the like, but is preferably performed using a roll press machine. The roll press is a method in which a film to be bonded is sandwiched between the rolls, and the rolls are rotated. The roll press is uniformly applied with pressure, and has a higher productivity than the sheet press and can be used preferably.

(Patterning)
The first electrode according to the present invention may be patterned. There is no particular limitation on the patterning method and process, and a known method can be applied as appropriate. For example, a patterned metal nanowire, a conductive polymer, or a layer containing a transparent conductive metal oxide is formed on a release surface, and then transferred onto a transparent substrate to form a patterned first electrode. Specifically, the following method can be preferably used.

i) A method of directly forming a layer containing a metal nanowire, a conductive polymer or a transparent conductive metal oxide in a pattern on a releasable substrate using a printing method
ii) A method of uniformly forming a layer containing metal nanowires, a conductive polymer, or a transparent conductive metal oxide on a releasable substrate and then patterning using a general photolithography process
iii) A method in which a metal nanowire containing an ultraviolet curable resin, a conductive polymer, or a layer containing a transparent conductive metal oxide is uniformly formed and then patterned like a photolithography process.
iv) A layer containing the metal nanowire, the conductive polymer, or the transparent conductive metal oxide according to the present invention is uniformly formed on a negative pattern previously formed of a photoresist on a releasable substrate, and a lift-off method is used. Patterning method.

  In any of the above methods, the patterned first electrode is transferred by transferring a layer containing a metal nanowire, a conductive polymer, or a transparent conductive metal oxide patterned on a releasable substrate onto a transparent substrate. Can be formed.

(Second electrode)
The 2nd electrode which concerns on this invention becomes a cathode in an organic photoelectric conversion element. Although the 2nd electrode part which concerns on this invention may be match | combined with a conductive material single layer, in addition to the material which has electroconductivity, you may use together resin which hold | maintains these. As the conductive material of the second electrode portion, a material having a small work function (4 eV or less) metal (referred to as an electron injecting metal), an alloy, an electrically conductive compound, and a mixture thereof is used.

Specific examples of such electrode materials include sodium, sodium-potassium alloy, magnesium, lithium, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al ₂ O ₃₎ mixture, indium, a lithium / aluminum mixture, and rare earth metals.

Among these, from the point of durability against electron injection and oxidation, etc., a mixture of an electron injecting metal and a second metal which is a stable metal having a larger work function than this, for example, a magnesium / silver mixture, Magnesium / aluminum mixtures, magnesium / indium mixtures, aluminum / aluminum oxide (Al ₂ O ₃ ) mixtures, lithium / aluminum mixtures, aluminum and the like are preferred.

  The cathode can be produced by forming a thin film of these electrode materials by a method such as vapor deposition or sputtering. The sheet resistance as the cathode is preferably several hundred Ω / □ or less, and the film thickness is usually selected in the range of 10 nm to 5 μm, preferably 50 to 200 nm.

  If a metal material is used as the conductive material of the second electrode, the light coming to the second electrode side is reflected and returns to the first electrode side. The metal nanowire of the first electrode scatters or reflects a part of the light backward, but the light can be reused by using a metal material as the conductive material of the second electrode, and the photoelectric conversion efficiency is further improved.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In addition, although the display of "part" or "%" is used in an Example, unless otherwise indicated, "part by mass" or "mass%" is represented.

Example 1
<< Production of Organic Photoelectric Conversion Element STC-1 >>
(Production of the first electrode TC-1)
ITO was vapor-deposited with an average film thickness of 150 nm on a PEN film having a barrier layer (total light transmittance of 90%) to produce a first electrode TC-1.

  On the first electrode TC-1, PEDOT / PSS (poly (3,4-ethylenedithiophene) -poly (styrenesulfonate)) (Baytron P4083, manufactured by HC Starck), which is a conductive polymer, has a thickness of 30 nm. After spin coating, it was dried by heating at 140 ° C. in the air for 10 minutes.

  After this, the substrate was brought into the glove box and worked under a nitrogen atmosphere. First, the substrate was heat-treated at 180 ° C. for 3 minutes in a nitrogen atmosphere.

Next, P3HT (poly-3-hexylthiophene) (manufactured by Reike Metal; Mn = 45000, regioregular type, polymer p-type semiconductor material) 1.0% by mass in chlorobenzene, PCBM (6,6-phenyl-C ₆₁ − A solution in which 1.0% by mass of butyric acid methyl ester (Mw = 911, low-molecular n-type semiconductor material) is prepared, filtered through a 0.45 μm filter for 60 seconds at 500 rpm, and then for 1 second at 2200 rpm After spin coating, the mixture was allowed to stand at room temperature for 30 minutes and then heated at 160 ° C. for 30 minutes.

Next, the first electrode on which the series of organic power generation layer portions was formed was placed in a vacuum evaporation apparatus. An element is set so that a 2 mm-wide shadow mask is orthogonal to the first electrode, the inside of the vacuum deposition apparatus is depressurized to 10 ⁻³ Pa or less, and then Al is deposited by 80 nm, and an organic photoelectric conversion element having a size of 2 mm square STC-1 was obtained.

  The obtained organic photoelectric conversion element STC-1 is a flexible material in which polyethylene terephthalate is used as a base material by applying an adhesive around the cathode electrode except for the ends so that external lead terminals of the anode electrode and the cathode electrode can be formed. After bonding the conductive sealing member, the adhesive was cured by heat treatment.

<< Production of Organic Photoelectric Conversion Element STC-2 >>
Ni isopropoxide was spin-coated on the first electrode TC-1 to a thickness of 10 nm after drying, and then heated and dried at 180 ° C. for 30 minutes.

  Thereafter, an organic photoelectric conversion element STC-2 was produced in the same manner as the organic photoelectric conversion element STC-1.

  The obtained organic photoelectric conversion element STC-2 is a flexible material in which polyethylene terephthalate is used as a base material by applying an adhesive around the cathode electrode except for the ends so that external lead terminals of the anode electrode and the cathode electrode can be formed. After bonding the conductive sealing member, the adhesive was cured by heat treatment.

<< Production of Organic Photoelectric Conversion Element STC-3 >>
(Preparation of metal nanowires)
Silver nanowires were used as metal nanowires. Silver nanowires are described in Adv. Mater. , 2002, 14, 833 to 837, silver nanowires having an average diameter of 75 nm and an average length of 35 μm were prepared, and the silver nanowires were filtered using an ultrafiltration membrane and washed with water. It re-dispersed in ethanol, and the silver nanowire dispersion liquid (silver nanowire content 5 mass%) was prepared.

(Production of the first electrode TC-3)
A biaxially stretched PET film was used as the releasable substrate. After the PET film surface is subjected to corona discharge treatment, the silver nanowire dispersion liquid is applied and dried using an applicator so that the amount of silver nanowires is 80 mg / m ² to form a silver nanowire network structure. did.

  Further, PEDOT / PSS (Baytron P4083, manufactured by HC Starck), which is a conductive polymer as a second transparent resin component, was overcoated on the above-described silver nanowire network structure so that the dry film thickness was 100 nm and dried. Then, it heat-processed at 80 degreeC for 3 hours. This is an AgNW-containing film for transfer.

  Next, the following UV curable transparent resin liquid 1 was applied as a first transparent resin component on a PEN film (total light transmittance 90%) having a barrier layer and an easy-adhesion layer so as to have a thickness of 5 μm, and then the above transfer It was pasted with an AgNW-containing film. Subsequently, after the first transparent resin component is sufficiently cured by irradiating with ultraviolet rays, the layer formed on the transfer AgNW-containing film is formed on the PEN film by peeling off the PET film which is a releasable substrate. The first electrode TC-3 according to the present invention was produced by transfer.

<UV curing transparent resin liquid 1>
SP-1 (manufactured by Asahi Denka) 3 parts by mass EP-1 20 parts by mass OXT221 (manufactured by Toagosei) 40.4 parts by mass OXT212 (manufactured by Toagosei) 25 parts by mass OXT101 (manufactured by Toagosei) 3 parts by mass propylene carbonate 3 parts by mass Parts Triisopropanolamine 0.1 parts by weight X-22-4272 (manufactured by Shin-Etsu Silicone) 0.5 parts by weight

  On the 1st electrode TC-3, it carried out similarly to organic photoelectric conversion element STC-2, and obtained organic photoelectric conversion element STC-3.

  The obtained organic photoelectric conversion element STC-3 is a flexible material in which polyethylene terephthalate is used as a base material by applying an adhesive around the cathode electrode except for the ends so that external lead terminals of the anode electrode and the cathode electrode can be formed. After bonding the conductive sealing member, the adhesive was cured by heat treatment.

<< Production of Organic Photoelectric Conversion Element STC-4 >>
A PEDOT / PSS layer and a photoelectric conversion layer were formed on the first electrode TC-3 in the same manner as the organic photoelectric conversion element STC-3.

  Next, a solution in which Ti-isopropoxide is dissolved in ethanol to a concentration of 0.05 mol / L is prepared, masked, and then applied to a film thickness of 20 nm, and left in nitrogen with a controlled amount of water vapor. Then, an electron transport layer was formed.

The 1st electrode which formed the said series of organic electric power generation layer part into a film was installed in the vacuum evaporation system. The element was set so that the 2 mm wide shadow mask was orthogonal to the first electrode, and the inside of the vacuum deposition apparatus was depressurized to 10 ⁻³ Pa or less, thereby obtaining an organic photoelectric conversion element STC-4 having a size of 2 mm square. .

  The obtained organic photoelectric conversion element STC-4 is a flexible material in which an adhesive is applied to the periphery of the cathode electrode except for the ends so that an external extraction terminal of the anode electrode and the cathode electrode can be formed, and polyethylene terephthalate is used as a base material. After bonding the conductive sealing member, the adhesive was cured by heat treatment.

<< Production of Organic Photoelectric Conversion Element STC-5 >>
In the production of the organic photoelectric conversion element STC-4, an organic photoelectric conversion element STC-5 was produced in the same manner except that Ni isopropoxide was spin-coated to a film thickness after drying of 6 nm.

<< Production of Organic Photoelectric Conversion Element STC-6 >>
(Production of the first electrode TC-6)
In the 1st electrode TC-3, it replaced with PEDOT / PSS, and the 1st electrode TC-6 was similarly used except the dry film thickness having been 200 nm using the following transparent inorganic ingredient content liquid B-1. Produced.

<Transparent inorganic component-containing liquid B-1>
Sb-doped SnO ₂ fine particles (SN100D manufactured by Ishihara Sangyo Co., Ltd., solid content 30%)
160g
Compound (UL-1) 0.2g
Modified polyester A (solid content 18%) 30 g
Finish up to 1000 ml with water.

(Synthesis of modified aqueous polyester A)
In a reaction vessel for polycondensation, 35.4 parts by mass of dimethyl terephthalate, 33.63 parts by mass of dimethyl isophthalate, 17.92 parts by mass of 5-sulfo-isophthalic acid dimethyl sodium salt, 62 parts by mass of ethylene glycol, calcium acetate monohydrate 0.065 parts by mass of salt and 0.022 parts by mass of manganese acetate tetrahydrate were added, and the ester exchange reaction was performed while distilling off methanol at 170 to 220 ° C. in a nitrogen stream. 04 parts by mass, 0.04 parts by mass of antimony trioxide as a polycondensation catalyst and 6.8 parts by mass of 1,4-cyclohexanedicarboxylic acid were added, and a theoretical amount of water was distilled off at a reaction temperature of 220 to 235 ° C. Esterification was performed.

  Thereafter, the reaction system was further depressurized and heated for about 1 hour, and finally subjected to polycondensation at 280 ° C. and 133 Pa or less for about 1 hour to obtain a modified aqueous polyester A precursor. The intrinsic viscosity of the precursor was 0.33.

  850 ml of pure water was put into a 2 L three-necked flask equipped with a stirring blade, a reflux condenser, and a thermometer, and 150 g of the precursor was gradually added while rotating the stirring blade. After stirring for 30 minutes at room temperature, the mixture was heated to an internal temperature of 98 ° C. over 1.5 hours, and heated and dissolved at this temperature for 3 hours. After completion of the heating, the mixture was cooled to room temperature over 1 hour and left overnight to prepare a solution having a solid content concentration of 15% by mass.

  1900 ml of the precursor solution was placed in a 3 L four-necked flask equipped with a stirring blade, a reflux condenser, a thermometer, and a dropping funnel, and the internal temperature was heated to 80 ° C. while rotating the stirring blade. Into this, 6.52 ml of a 24% aqueous solution of ammonium persulfate was added, and a monomer mixture (28.5 g of glycidyl methacrylate, 21.4 g of ethyl acrylate, 21.4 g of methyl methacrylate) was dropped over 30 minutes. The reaction was continued for another 3 hours. Then, it cooled to 30 degrees C or less, and filtered, and prepared the solution of the modified aqueous polyester A whose solid content concentration is 18 mass% (polyester component / acrylic component = 80/20).

  In the production of the organic photoelectric conversion element STC-4, an organic photoelectric conversion element STC-6 was produced in the same manner except that the first electrode was changed from TC-3 to TC-6.

  The obtained organic photoelectric conversion element STC-6 is a flexible material based on polyethylene terephthalate and coated with an adhesive around the cathode electrode except for the ends so that external lead terminals of the anode electrode and the cathode electrode can be formed. After bonding the conductive sealing member, the adhesive was cured by heat treatment.

<< Preparation of organic photoelectric conversion element STC-7 >>
In the production of the organic photoelectric conversion element STC-3, after spin-coating Ni isopropoxide on the first electrode TC-1 to a film thickness of 10 nm after drying, it was produced by heat drying at 180 ° C. for 30 minutes. Organic photoelectric conversion element STC-7 was produced in the same manner except that the NiO layer was formed by the LPD method so that the film thickness after drying was 10 nm instead of the electron blocking layer.

  In the same manner as described above, the obtained organic photoelectric conversion element STC-7 was coated with an adhesive around the cathode electrode except for the ends so that external terminals for the anode electrode and the cathode electrode could be formed, and was based on polyethylene terephthalate. After bonding the flexible sealing member used as the material, the adhesive was cured by heat treatment.

[Evaluation of organic photoelectric conversion elements]
<< Photoelectric conversion efficiency >>
An organic photoelectric conversion element sealed with a glass sealing cap and a UV curable resin is irradiated with light from a solar simulator (AM1.5G) at an intensity of 100 mW / cm ² to obtain voltage-current characteristics. The photoelectric conversion efficiency was determined by measurement. That is, for each organic photoelectric conversion element, current-voltage characteristics are measured at room temperature using an IV tester, and a short circuit current (Jsc), an open circuit voltage (Voc), and a form factor (FF) are obtained. From these, the photoelectric conversion efficiency (η (%)) was determined. In addition, the photoelectric conversion efficiency ((eta) (%)) of the solar cell was computed based on the following formula (A). η = 100 × (Voc × Jsc × FF) / P (A)
Here, P is the incident light intensity [mW / cm ⁻² ], Voc is the open circuit voltage [V], Jsc is the short circuit current density [mA · cm ⁻² ], F. Indicates a form factor.

《Bending resistance (Retention degree of energy conversion efficiency after bending)》
The change in energy conversion efficiency before and after the obtained organic photoelectric conversion element was wound around a 2 inch φ (1 inch is 2.54 cm) rod 30 times each was wound around the energy conversion efficiency before winding. The subsequent energy conversion efficiency was calculated as the retention rate and is shown in Table 1.

  Retention rate = energy conversion efficiency after winding / energy conversion efficiency after winding × 100 (%)

  From Table 1, it can be seen that the organic photoelectric conversion element of the present invention has high photoelectric conversion efficiency. In particular, it can be seen that a configuration in which an electron transport layer having a blocking function is provided between the first electrode made of the conductive fiber of the present invention and the cathode and the photoelectric conversion layer is more preferable. In addition, the organic photoelectric conversion element having the electron block layer produced by the LPD method shows a decrease in the retention due to the retention of the energy conversion efficiency before and after the winding, whereas the organic photoelectric conversion device having the configuration of the present invention. It was found that the conversion element has improved bending resistance.

Example 2
<< Precursor A of p-type semiconductor material >>
Chemical Communications, Vol. 22 (1999), p2275, a BP-1 precursor of a p-type semiconductor material was obtained.

<< Production of Organic Photoelectric Conversion Elements STC-21 to 26 >>
In the production of the organic photoelectric conversion elements STC-1 to STC-6, the organic photoelectric conversion elements STC-21 to STC-21 are similarly manufactured except that 1.2% by mass of the BP-1 precursor is used instead of 1.0% by mass of P3HT. 26 was obtained.

  When evaluated in the same manner as in Example 1, it was confirmed that the effects of the present invention were obtained.

It is a structure schematic diagram of the 1st electrode which has a transparent conductive layer concerning the present invention. It is another structure schematic diagram of the 1st electrode which has translucency which concerns on this invention. It is sectional drawing which shows the bulk heterojunction type organic photoelectric conversion element of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Metal nanowire 2 2nd transparent resin component containing part or transparent inorganic component containing part 3 1st transparent resin 4 1st electrode 10 Bulk heterojunction type organic photoelectric conversion element 11 Transparent substrate 12 1st electrode 13 2nd electrode 14 Photoelectric conversion layer 15 Electronic block layer

Claims (8)

An organic photoelectric conversion element having at least a first electrode, a photoelectric conversion layer, and a second electrode on a transparent substrate, respectively, comprising a p-type metal oxide formed by a wet method between the first electrode and the photoelectric conversion layer An organic photoelectric conversion element provided with an electron block layer. The organic photoelectric conversion element according to claim 1, wherein the electron blocking layer is made of amorphous NiO. 3. The organic photoelectric conversion element according to claim 1, wherein the surface of the first electrode is composed of a conductive fiber and a transparent conductive material. The organic photoelectric conversion element according to claim 3, wherein the conductive fiber is at least one selected from the group consisting of metal nanowires and carbon nanotubes. The organic photoelectric conversion element according to claim 3 or 4, wherein the transparent conductive material is at least one selected from the group of conductive polymers and conductive metal oxide fine particles. An organic photoelectric conversion element manufacturing method comprising: forming an electron blocking layer by a wet method after forming a first electrode on a substrate at atmospheric pressure; and providing a photoelectric conversion layer and a second electrode thereon. The method for producing an organic photoelectric conversion element according to claim 6, wherein the electron blocking layer formed by the wet method is amorphous NiO. 8. The method of manufacturing an organic photoelectric conversion element according to claim 7, wherein the electron blocking layer made of amorphous NiO is formed by applying a Ni alkoxide solution and drying at room temperature.

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