JP2012134337A - Organic photoelectric conversion element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic photoelectric conversion element having enhanced energy conversion efficiency with high productivity.SOLUTION: The tandem organic photoelectric conversion element has two or more photoelectric conversion layers. The organic photoelectric conversion element has at least one recombination layer containing 70 mass% or more of an organic matter, and a charge transport layer which transports electrons or holes selectively between at least one pair of adjoining photoelectric conversion layers out of the two or more photoelectric conversion layers. The recombination layer has electric conductivity of 5-50,000 S/cm.

Description

  The present invention relates to an organic photoelectric conversion element, and more particularly to a tandem organic photoelectric conversion element having at least two photoelectric conversion layers.

  The organic photoelectric conversion element has a structure in which a photoelectric conversion layer made of an organic substance and a charge transport layer are laminated on a transparent electrode, and is further sandwiched between the electrodes. It is a device that drives Furthermore, by using a highly flexible transparent resin substrate, not only can a flexible organic photoelectric conversion element be realized, but the organic layer can be coated and formed by roll-to-roll using a production facility such as a die coater. A low-cost and high-productivity process can be expected.

  In a photoelectric conversion element, in order to effectively utilize sunlight widely distributed from ultraviolet rays to visible light and infrared rays, a tandem element configuration in which a plurality of photoelectric conversion layers are stacked is widely known, and also in an organic photoelectric conversion element For example, Patent Documents 1 to 3 and Non-Patent Documents 1 to 3 propose tandem element configurations. In an organic photoelectric conversion element, a recombination layer is used to efficiently recombine electrons and holes generated in the photoelectric conversion layer between two or more photoelectric conversion layers constituting the tandem element, thereby improving the photoelectric conversion efficiency. In Non-patent Documents 1 and 2 and Patent Document 1, a layer made of metal nanoparticles formed by a vapor deposition method is provided as a recombination layer. However, when the metal nanoparticle layer is formed by vapor deposition, it is necessary to introduce a vacuum process, which has problems in terms of productivity and cost, and the advantages of the organic photoelectric conversion element have been lost. .

  In addition, a method of forming highly transparent ITO in the recombination layer in place of the metal nanoparticles is known (for example, see Patent Document 2). Productivity was low. In Non-Patent Document 3, an inorganic semiconductor layer made of titanium oxide formed by a sol-gel method without using a vapor deposition method is used. However, a hole transport layer and an electron transport layer made of an inorganic oxide are sol-gel. Laminating by the method, sputtering, etc., precipitation at the time of coating, and a vacuum process were necessary, and there were problems in production.

  Thus, in order to improve the energy conversion efficiency of the organic photoelectric conversion element, an organic photoelectric conversion element having a tandem configuration is desired. In order to take advantage of the high productivity of the organic photoelectric conversion element, There has been a demand for an element configuration having a layer which is substantially made of an organic substance and can be formed by coating between two or more photoelectric conversion layers constituting the photoelectric conversion element. Further, in the conventional method, the output of the tandem configuration is not the sum of two or more subcells, causing a loss of efficiency, and an improvement thereof has been demanded.

  Non-Patent Document 3 and Patent Document 3 disclose a method of using a layer substantially composed of an organic substance between two or more photoelectric conversion layers. However, the necessary requirements of the organic layer are sufficiently clarified. It wasn't. Moreover, there was no description about the charge transport layer adjacent to the recombination layer made of organic matter.

JP-T-2006-520533 JP 2006-279011 A JP-T-2006-527490

M.M. Hiromoto, Chem. Lett. 1990,327 S. T.A. Forrest, J. et al. Apply. Phys. Lett. , 2004, 96, 7519 A. J. et al. Heeger, Science 2007, 317, 222

  The present invention has been made in view of the above problems, and an object thereof is to provide an organic photoelectric conversion element having good productivity and improved energy conversion efficiency.

  The above object of the present invention is achieved by the following configurations.

  1. A tandem organic photoelectric conversion element having at least two photoelectric conversion layers, wherein 70% by mass of organic matter is present between at least one pair of adjacent photoelectric conversion layers among the two or more photoelectric conversion layers. An organic photoelectric sensor characterized by having at least one recombination layer and a charge transport layer that selectively transports electrons or holes, and the recombination layer has a conductivity of 5 to 50,000 S / cm. Conversion element.

  2. 2. The organic photoelectric conversion element as described in 1 above, wherein the electrical conductivity of the recombination layer is 10 to 10,000 S / cm.

3. 3. The organic according to 1 or 2, wherein among the charge transport layers, the conductivity of a charge transport layer (hole transport layer) that selectively transports holes is 10 ^{−5 to 1} S / cm. Photoelectric conversion element.

  According to the present invention, an organic photoelectric conversion element with good productivity and improved energy conversion efficiency could be provided.

It is a schematic diagram which shows the cross-section of the organic photoelectric conversion element of this invention.

  As a result of intensive studies in view of the above problems, the present inventor is a tandem organic photoelectric conversion element having at least two photoelectric conversion layers, and at least one pair of the two or more photoelectric conversion layers. The organic substance has a recombination layer and a charge transport layer of 70% by mass or more between adjacent photoelectric conversion layers, and the conductivity of the recombination layer is 5 to 50,000 S / cm. It has been found that an organic photoelectric conversion element having good properties and improved energy conversion efficiency can be realized, and the present invention has been achieved.

  In such a tandem organic photoelectric conversion element, by connecting two photoelectric conversion layers through a recombination layer, the recombination sites of holes and electrons are increased, and the energy conversion efficiency is improved. In order to increase the productivity of the photoelectric conversion element, it is preferable that it can be installed by coating, and there are known examples in which a recombination layer or a charge transport layer made of an organic material is made of a completely organic material instead of a conventional metal or metal oxide. It was not done. In the present invention, although the detailed mechanism is unknown, the recombination layer is effective as a recombination layer with a conductivity of 5 S / cm or more due to the selective conductivity of holes and electrons in the charge transport layer and the recombination layer. I think it works. The conductivity of the recombination layer is preferably higher from the viewpoint of reducing the resistance, but if it becomes too high, the charge transport property of the charge transport layer and the recombination layer will be out of balance and will not function effectively as a recombination layer. In the present invention, the recombination layer preferably has a conductivity of 5 to 50,000 S / cm. In particular, the electrical conductivity of the recombination layer is preferably 10 to 10,000 S / cm.

  In addition, the present invention is characterized in that a recombination layer and a charge transport layer are provided between two photoelectric conversion layers, and these layers are composed of an organic substance of 70% by mass or more. 80 mass% or more is preferable and the organic substance of these layers has more preferable 90 mass% or more. If an organic substance is this range, an inorganic compound may be included.

  A form including three or more photoelectric conversion layers is also included in the present invention.

  Hereinafter, the present invention will be described in more detail.

[Configuration of organic photoelectric conversion element]
Although the preferable form of the organic photoelectric conversion element of this invention is demonstrated using FIG. 1, it is not limited to this.

  FIG. 1 is a schematic view showing a cross-sectional structure of a preferred organic photoelectric conversion device of the present invention.

  In FIG. 1A, the organic photoelectric conversion element 10 is formed on a substrate 100 with a first electrode (transparent electrode, cathode) 101, a first electron transport layer 102, a first photoelectric conversion layer 103, and a first hole transport layer 104. 1 shows a structure in which a recombination layer 105, a second electron transport layer 106, a second photoelectric conversion layer 107, a second hole transport layer 108, and a second electrode (anode) 109 are stacked.

  In FIG. 1B, the organic photoelectric conversion element 20 is formed on a substrate 100 with a first electrode (transparent electrode, cathode) 201, a first hole transport layer 104, a first photoelectric conversion layer 103, and a first electron transport layer 102. 1 shows a structure in which a recombination layer 105, a second hole transport layer 108, a second photoelectric conversion layer 107, a second electron transport layer 106, and a second electrode (cathode) 209 are stacked.

(Recombination layer)
In this invention, it has a recombination layer between the at least 2 photoelectric conversion layers which form a tandem element, this layer consists of 70 mass% or more organic substance, and electrical conductivity is 5-50,000 S / cm. It is characterized by. The electrical conductivity is more preferably 100 to 10,000 S / cm.

  Such conductivity can be achieved by adding the following conductive polymer material and dopant.

  Further, the transparency of the recombination layer is preferably 80% or more and more preferably 90% or more in the absorption wavelength region (380 to 800 nm) of the photoelectric conversion layer. The thickness of the recombination layer is preferably 1-1000 nm, more preferably 5-50 nm.

  The material constituting the recombination layer is not particularly limited as long as it is a conductive organic material that achieves the above-described conductivity and transmittance, and may be composed of one kind of material or a plurality of materials. The molecular weight is not particularly limited, but a conductive polymer compound is preferably used.

(Conductive polymer)
Examples of the conductive polymer applied to the transparent conductive material according to the present invention include polypyrrole, polyaniline, polythiophene, polythienylene vinylene, polyazulene, polyisothianaphthene, polycarbazole, polyacetylene, polyphenylene, polyphenylene vinylene, and polyacene. And compounds selected from the group consisting of derivatives of polyphenylacetylene, polydiacetylene and polynaphthalene.

  The conductive polymer according to the present invention may contain one type of conductive polymer alone, or may contain two or more types of conductive polymers in combination, but the conductivity and transparency. In view of the above, polyaniline having a repeating unit represented by the following general formula (I) or general formula (II) or a derivative thereof, a polypyrrole derivative having a repeating unit represented by the following general formula (III), or the following general formula ( More preferably, it contains at least one compound selected from the group consisting of polythiophene derivatives having a repeating unit represented by IV).

  In the above general formulas (III) and (IV), R is mainly a linear organic substituent, preferably an alkyl group, an alkoxy group, an allyl group, or a combination of these groups. As long as it does not lose its properties, a sulfonate group, an ester group, an amide group, or the like may be bonded to or combined with these. Note that n is an integer.

The transparent conductive polymer according to the present invention can be subjected to a doping treatment in order to obtain a predetermined conductivity. As a dopant for the conductive polymer, for example, a sulfonic acid having a hydrocarbon group having 6 to 30 carbon atoms (hereinafter also referred to as a long-chain sulfonic acid) or a polymer thereof (for example, polystyrene sulfonic acid), a halogen atom , Lewis acid, proton acid, transition metal halide, transition metal compound, alkali metal, alkaline earth metal, MClO ₄ (M = Li ⁺ , Na ⁺ ), R ₄ N ⁺ (R═CH ₃ , C ₄ H ₉ , C ₆ H ₅ ), or R ₄ P ⁺ (R═CH ₃ , C ₄ H ₉ , C ₆ H ₅ ). Of these, the long-chain sulfonic acid is preferable.

  The dopant for the conductive polymer may be introduced into fullerenes such as hydrogenated fullerene, hydroxylated fullerene, and sulfonated fullerene. It is preferable that 0.001 mass part or more of the said dopant is contained with respect to 100 mass parts of conductive polymers. Furthermore, it is more preferable that 0.5 mass part or more is contained.

The conductive polymer according to the present invention includes a long-chain sulfonic acid, a polymer of long-chain sulfonic acid (for example, polystyrene sulfonic acid), halogen, Lewis acid, proton acid, transition metal halide, transition metal compound, alkali Both at least one dopant selected from the group consisting of metals, alkaline earth metals, MClO ₄ , R ₄ N ⁺ , and R ₄ P ⁺ and fullerenes may be included.

  The transparent conductive material containing the conductive polymer according to the present invention may contain a water-soluble organic compound. Among water-soluble organic compounds, compounds having an effect of improving conductivity by adding to a conductive polymer material are known, and 2nd. Sometimes called a dopant (or sensitizer). 2nd. Which can be used in the highly conductive material according to the present invention. There is no restriction | limiting in particular in a dopant, It can select suitably from well-known things, For example, a dimethyl sulfoxide (DMSO), diethylene glycol, and another oxygen containing compound are mentioned suitably.

  In the transparent conductive material containing the conductive polymer according to the present invention, the 2nd. 0.001 mass part or more is preferable, as for content of a dopant, 0.01-50 mass parts is more preferable, and 0.01-10 mass parts is especially preferable.

  The transparent conductive material containing the conductive polymer according to the present invention may contain a transparent resin component or additive in addition to the conductive polymer in order to ensure film formability and film strength. The transparent resin component is not particularly limited as long as it is compatible with or mixed with the conductive polymer, and may be a thermosetting resin or a thermoplastic resin. For example, polyester resins such as polyethylene terephthalate, polybutylene terephthalate and polyethylene naphthalate, polyimide resins such as polyimide and polyamideimide, polyamide resins such as polyamide 6, polyamide 6,6, polyamide 12 and polyamide 11, polyvinylidene fluoride, Fluorine resin such as polyvinyl fluoride, polytetrafluoroethylene, ethylene tetrafluoroethylene copolymer, polychlorotrifluoroethylene, etc., vinyl resin such as polyvinyl alcohol, polyvinyl ether, polyvinyl butyral, polyvinyl acetate, polyvinyl chloride, epoxy resin, xylene Resin, aramid resin, polyurethane resin, polyurea resin, melamine resin, phenol resin, polyether, acrylic resin and their co-polymer Body, and the like.

[Charge transport layer: hole transport layer, electron transport layer]
In the present invention, a charge transport layer is provided between at least two photoelectric conversion layers forming a tandem element, and this layer is made of 70% by mass or more of an organic substance.

  The original function of the charge transport layer is to serve as a blocking layer that transports one of holes or electrons generated in the photoelectric conversion layer to the electrode and prevents transport of the opposite carrier. In this case, the hole transport layer can be referred to as an electron blocking layer, and the electron transport layer as a hole blocking layer.

  In the present invention, either one of the recombination layer and the two photoelectric conversion layers located on both sides thereof has charge transport composed of 70% by mass or more of an organic substance. More specifically, an embodiment having an electron transport layer between the recombination layer and the photoelectric conversion layer located on the anode side or a hole transport layer between the recombination layer and the photoelectric conversion layer located on the cathode side is preferable. . It is an aspect of the present invention that either the electron transport layer or the hole transport layer exists between the photoelectric conversion layers, but the electron transport layer is interposed between the recombination layer and the photoelectric conversion layer located on the anode side. More preferably, the hole transport layer is provided between the recombination layer and the photoelectric conversion layer located on the cathode side.

  The electron transport layer has a function of an electron transport layer in a broad sense, and more specifically, a material having a function of transporting electrons and a very small ability to transport holes (preferably, ten times or more in mobility). It is possible to improve the recombination probability in the recombination layer of electrons and holes by blocking hole movement while transporting electrons.

  On the other hand, the hole transport layer has a function of a hole transport layer in a broad sense, and more specifically, a material having a function of transporting holes and a remarkably small ability to transport electrons (preferably having a mobility of 10 The recombination probability of electrons and holes can be improved by blocking the electron movement while transporting holes.

  The thickness of the charge transport layer is preferably 1 to 2000 nm. From the viewpoint of further improving the leak prevention effect, the film thickness is more preferably 5 nm or more. Moreover, it is preferable that it is a film thickness of 1000 nm or less from a viewpoint of maintaining a high transmittance | permeability and low resistance, and it is more preferable that it is 200 nm or less.

In addition, the conductivity of the charge transport layer is preferably high, but if it is too high, the conductivity against the reverse charge increases and the blocking ability against the reverse charge decreases, and the rectifying property (the charge on the opposite side to one charge) is reduced. Of the charge transport layer, the conductivity of the charge transport layer (hole transport layer) that selectively transports holes is 10 ^{−5 to 1} S / cm. More preferably, it is 10 ⁻⁴ to 10 ⁻² S / cm.

(Hole transport layer)
The hole transport layer is made of a hole transport material having a function of transporting holes, and in a broad sense, a hole injection layer and an electron blocking layer are also included in the hole transport layer. The hole transport layer can be provided as a single layer or a plurality of layers.

  As a hole transport material, there is a material having either hole injection or transport or electron barrier property, which is mainly made of an organic material and can be easily installed by coating. For example, triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives and pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, Examples thereof include stilbene derivatives, silazane derivatives, aniline copolymers, and conductive polymer oligomers, particularly thiophene oligomers.

  The above-mentioned materials can be used as the hole transport material, but it is preferable to use a porphyrin compound, an aromatic tertiary amine compound and a styrylamine compound, particularly an aromatic tertiary amine compound.

  Furthermore, a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used. JP-A-11-251067, J. Org. Huang et. al. A so-called p-type hole transport material described in a book (Applied Physics Letters, 80 (2002), p. 139) can also be used.

  Alternatively, a hole transport layer having a high p property doped with impurities can be used. Examples thereof include JP-A-4-297076, JP-A-2000-196140, 2001-102175, J.A. Appl. Phys. 95, 5773 (2004), and the like.

  These materials are preferably those that form a coating film by chemical bonding or physical adhesion after the coating film is formed so that they can be laminated by coating. In order to promote chemical-physical adhesion, reactive groups can be used. , Introduction of cross-linking groups. Introduction of reactive compounds. Adhesion promotion measures such as fusion by heat treatment can be taken.

(Electron transport layer)
The electron transport layer is made of a material having a function of transporting electrons, and in a broad sense, an electron injection layer and a hole blocking layer are also included in the electron transport layer. It is an aspect of the present invention that the electron transport layer is mainly composed of an organic substance and can be easily installed by coating.

  As the material, any one of conventionally known compounds can be selected and used. For example, nitro-substituted fluorene derivatives, diphenylquinone derivatives, thiopyran dioxide derivatives, carbodiimides, fluorenylidenemethane derivatives, anthraquino Examples include dimethane and anthrone derivatives, oxadiazole derivatives, and the like. Furthermore, in the above oxadiazole derivative, a thiadiazole derivative in which the oxygen atom of the oxadiazole ring is substituted with a sulfur atom, and a quinoxaline derivative having a quinoxaline ring known as an electron withdrawing group can also be used as an electron transport material. Furthermore, a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used.

In addition, metal complexes of 8-quinolinol derivatives such as tris (8-quinolinol) aluminum (Alq ₃ ), tris (5,7-dichloro-8-quinolinol) aluminum, tris (5,7-dibromo-8-quinolinol) Aluminum, tris (2-methyl-8-quinolinol) aluminum, tris (5-methyl-8-quinolinol) aluminum, bis (8-quinolinol) zinc (Znq), etc., and the central metals of these metal complexes are In, Mg Metal complexes replaced with Cu, Ca, Sn, Ga, or Pb can also be used as electron transport materials. In addition, metal-free or metal phthalocyanine, or those having terminal ends substituted with an alkyl group or a sulfonic acid group can be preferably used as the electron transporting material.

  Further, an electron transport layer having a high n property doped with impurities can also be used. Examples thereof include JP-A-4-297076, JP-A-10-270172, JP-A-2000-196140, 2001-102175, J.A. Appl. Phys. 95, 5773 (2004), and the like.

  Specific examples include N, N′-bis (3-methylphenyl)-(1,1′-biphenyl) -4,4′-diamine (TPD) and 4,4′-bis [N- (naphthyl)- Aromatic diamine compounds such as N-phenyl-amino] biphenyl (α-NPD) and derivatives thereof, oxazole, oxadiazole, triazole, imidazole, imidazolone, stilbene derivative, pyrazoline derivative, tetrahydroimidazole, polyarylalkane, butadiene, 4 , 4 ', 4 "-tris (N- (3-methylphenyl) N-phenylamino) triphenylamine (m-MTDATA), porphine, tetraphenylporphine copper, phthalocyanine, copper phthalocyanine, titanium phthalocyanine oxide, etc. , Triazole derivatives, oxa Zazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, annealed amine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, silazane derivatives, etc. In the polymer material, polymers such as phenylene vinylene, fluorene, carbazole, indole, pyrene, pyrrole, picoline, thiophene, acetylene, diacetylene, and derivatives thereof can be preferably used.

  These materials are preferably those that form a coating film by chemical bonding or physical adhesion after the coating film is formed so that they can be laminated by coating. In order to promote chemical-physical adhesion, reactive groups can be used. , Introduction of cross-linking groups. Introduction of reactive compounds. Adhesion promotion measures such as fusion by heat treatment can be taken.

[Photoelectric conversion layer]
The photoelectric conversion layer according to the present invention is preferably a bulk heterojunction type photoelectric conversion layer using a p-type semiconductor material and an n-type semiconductor material.

(P-type semiconductor material)
Examples of the p-type semiconductor material used for the photoelectric conversion layer according to the present invention include various condensed polycyclic aromatic low molecular compounds and conjugated polymers.

  Examples of the condensed polycyclic aromatic low molecular weight compound include anthracene, tetracene, pentacene, hexacene, heptacene, chrysene, picene, fluorene, pyrene, peropyrene, perylene, terylene, quaterylene, coronene, ovalene, thacumanthracene, bisanthene, zeslene. , Heptazethrene, pyranthrene, violanthene, isoviolanthene, cacobiphenyl, anthradithiophene, etc., porphyrin, copper phthalocyanine, tetrathiafulvalene (TTF) -tetracyanoquinodimethane (TCNQ) complex, bisethylenetetrathiafulvalene ( BEDTTTTF) -perchloric acid complexes, and derivatives and precursors thereof.

  Examples of the derivative having the above-mentioned condensed polycycle include WO 03/16599 pamphlet, WO 03/28125 pamphlet, US Pat. No. 6,690,029, JP 2004-107216 A. A pentacene derivative having a substituent described in JP-A-2003-136964, a pentacene precursor described in US Patent Application Publication No. 2003/136964, and the like; Amer. Chem. Soc. , Vol. 127, no. 14, p 4986, J. MoI. Amer. Chem. Soc. , Vol. 123, p9482; Amer. Chem. Soc. , Vol. 130 (2008), no. 9, acene compounds substituted with a trialkylsilylethynyl group described in p2706 and the like.

  As the conjugated polymer, for example, a polythiophene such as poly-3-hexylthiophene (P3HT) and an oligomer thereof, or a technical group described in Technical Digest of the International PVSEC-17, Fukuoka, Japan, 2007, P1225. Polythiophene, Nature Material, (2006) vol. 5, p328, polythiophene-thienothiophene copolymer, polythiophene-diketopyrrolopyrrole copolymer described in WO2008000664, Adv. Mater. , 2007, p4160, a polythiophene-thiazolothiazole copolymer, Nature Mat. , Vol. 6 (2007), p497 described in PCPDTBT, polypyrrole and its oligomer, polyaniline, polyphenylene and its oligomer, polyphenylene vinylene and its oligomer, polythienylene vinylene and its oligomer, polyacetylene, polydiacetylene, Examples thereof include polymer materials such as σ-conjugated polymers such as polysilane and polygermane.

  In addition, oligomeric materials instead of polymer materials include thiophene hexamer α-sexual thiophene α, ω-dihexyl-α-sexual thiophene, α, ω-dihexyl-α-kinkethiophene, α, ω-bis (3 Oligomers such as -butoxypropyl) -α-sexithiophene can be preferably used.

  Among these compounds, compounds that have high solubility in organic solvents to the extent that solution processing is possible, can form a crystalline thin film after drying, and can achieve high mobility are preferable. In addition, when the electron transport layer is formed on the photoelectric conversion layer by coating, there is a problem that the electron transport layer solution dissolves the photoelectric conversion layer, so a material that can be insolubilized after being applied by a solution process is used. Also good.

  Examples of such materials include materials that can be insolubilized by polymerizing the coating film after coating, such as polythiophene having a polymerizable group described in Technical Digest of the International PVSEC-17, Fukuoka, Japan, 2007, P1225. Or a soluble substituent reacts and insolubilizes by applying energy such as heat as described in U.S. Patent Application Publication No. 2003/136964 and JP-A-2008-16834 (pigment). Material) and the like.

<N-type semiconductor material>
The n-type semiconductor material used for the photoelectric conversion layer according to the present invention is not particularly limited. For example, fullerene, octaazaporphyrin, and the like, p-type semiconductor perfluoro products (perfluoropentacene, perfluorophthalocyanine, etc.), naphthalene, and the like. Examples thereof include aromatic carboxylic acid anhydrides such as tetracarboxylic acid anhydride, naphthalene tetracarboxylic acid diimide, perylene tetracarboxylic acid anhydride, and perylene tetracarboxylic acid diimide, and polymer compounds containing the imidized product thereof as a skeleton.

  However, when a material having a thiophene-containing condensed ring is used as the p-type semiconductor material, a fullerene derivative capable of efficient charge separation is preferable. Fullerene derivatives include fullerene C60, fullerene C70, fullerene C76, fullerene C78, fullerene C84, fullerene C240, fullerene C540, mixed fullerene, fullerene nanotubes, multi-walled nanotubes, single-walled nanotubes, nanohorns (conical), etc. Partially by hydrogen atom, halogen atom, substituted or unsubstituted alkyl group, alkenyl group, alkynyl group, aryl group, heteroaryl group, cycloalkyl group, silyl group, ether group, thioether group, amino group, silyl group, etc. Examples thereof include substituted fullerene derivatives.

  Among them, [6,6] -phenyl C61-butyric acid methyl ester (abbreviation PCBM), [6,6] -phenyl C61-butyric acid-nbutyl ester (PCBnB), [6,6] -phenyl C61-buty Rick acid-isobutyl ester (PCBiB), [6,6] -phenyl C61-butyric acid-n hexyl ester (PCBH), Adv. Mater. , Vol. 20 (2008), p2116, etc., aminated fullerenes such as JP-A 2006-199674, metallocene fullerenes such as JP-A 2008-130889, and cyclics such as US Pat. No. 7,329,709. It is preferable to use a fullerene derivative having a substituent and having improved solubility, such as fullerene having an ether group.

[Other functional layers]
The organic photoelectric conversion device of the present invention may have various intermediate layers in the device for the purpose of improving energy conversion efficiency and device life. Examples of the intermediate layer include a UV absorption layer, a light reflection layer, a wavelength conversion layer, and a smoothing layer.

〔electrode〕
(Transparent electrode)
In the transparent electrode according to the present invention, the cathode and the anode are not particularly limited, and can be selected depending on the element configuration, but it is generally used as an anode. In the present invention, the anode means an electrode for extracting holes. For example, when used as an anode, it is preferably an electrode that transmits light of 380 to 800 nm. As the material, for example, transparent conductive metal oxides such as indium tin oxide (ITO), SnO ₂ and ZnO, metal thin films such as gold, silver and platinum, metal nanowires and carbon nanotubes can be used.

  Also, a conductive material selected from the group consisting of polypyrrole, polyaniline, polythiophene, polythienylene vinylene, polyazulene, polyisothianaphthene, polycarbazole, polyacetylene, polyphenylene, polyphenylene vinylene, polyacene, polyphenylacetylene, polydiacetylene and polynaphthalene. A functional polymer can also be used. A plurality of these conductive compounds can be combined to form a transparent electrode.

(Counter electrode)
In the counter electrode according to the present invention, the cathode and the anode are not particularly limited, and can be selected depending on the element structure, but it is generally used as a cathode. In the present invention, the cathode means an electrode for taking out electrons. For example, when used as a cathode, the counter electrode may be a single layer of a conductive material, but in addition to a conductive material, a resin that holds these may be used in combination. The counter electrode may be a single layer of a conductive material, but in addition to a conductive material, a resin that holds these may be used in combination. As the conductive material of the counter electrode, a material having a small work function (4 eV or less) metal, alloy, 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 ) Mixtures, indium, lithium / aluminum mixtures, rare earth metals and the like. Among these, from the viewpoint of electron extraction performance and durability against oxidation, etc., a mixture of these metals and a second metal which is a stable metal having a larger work function value 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 counter electrode can be produced by forming a thin film of these electrode materials by a method such as vapor deposition or sputtering. 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 counter electrode, the light coming to the counter electrode side is reflected and reflected to the first electrode side, and this light can be reused and is absorbed again by the photoelectric conversion layer, and more photoelectric conversion efficiency Is preferable.

  The counter electrode may be a metal (eg, gold, silver, copper, platinum, rhodium, ruthenium, aluminum, magnesium, indium, etc.), carbon nanoparticle, nanowire, or nanostructure. A dispersion is preferable because a transparent and highly conductive counter electrode can be formed by a coating method.

  Moreover, when making the counter electrode side light-transmitting, for example, after forming a conductive material suitable for the counter electrode such as aluminum and aluminum alloy, silver and silver compound in a thin film thickness of about 1 to 20 nm, By providing a film of the conductive light transmissive material mentioned in the description of the transparent electrode, a light transmissive counter electrode can be obtained.

〔substrate〕
When light that is photoelectrically converted enters from the substrate side, the substrate is preferably a member that can transmit the light that is photoelectrically converted, that is, a member that is transparent to the wavelength of the light to be photoelectrically converted. As the substrate, for example, a glass substrate, a resin substrate and the like are preferably mentioned, but it is desirable to use a transparent resin film from the viewpoint of light weight and flexibility.

  There is no restriction | limiting in particular in the transparent resin film which can be preferably used as a transparent substrate by this invention, The material, a shape, a structure, thickness, etc. can be suitably selected from well-known things. For example, polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN) modified polyester, polyethylene (PE) resin film, polypropylene (PP) resin film, polystyrene resin film, polyolefin resins such as cyclic olefin resin Film, vinyl resin film such as polyvinyl chloride, polyvinylidene chloride, polyether ether ketone (PEEK) resin film, polysulfone (PSF) resin film, polyether sulfone (PES) resin film, polycarbonate (PC) resin film, A polyamide resin 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 at ~800nm), can be preferably applied to a transparent resin film according to the present invention. Among these, 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, and biaxially stretched. More preferred are polyethylene terephthalate films and biaxially stretched polyethylene naphthalate films.

  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 adhesiveness 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.

  Further, for the purpose of suppressing the permeation of oxygen and water vapor, 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 opposite side to which the transparent conductive layer is transferred. Good.

[Other optical functional layers]
The organic photoelectric conversion element of the present invention may have various optical functional layers for the purpose of more efficient reception of sunlight. As the optical functional layer, for example, a light condensing layer such as an antireflection film or a microlens array, or a light diffusion layer that can scatter light reflected by the cathode and enter the photoelectric conversion layer again can be provided. Good.

  Various known antireflection layers can be provided as the antireflection layer. For example, when the transparent resin film is a biaxially stretched polyethylene terephthalate film, the refractive index of the easy adhesion layer adjacent to the film is 1.57. It is more preferable to set it to ˜1.63 because the interface reflection between the film substrate and the easy adhesion layer can be reduced and the transmittance can be improved. The method for adjusting the refractive index can be carried out by appropriately adjusting the ratio of the oxide sol having a relatively high refractive index such as tin oxide sol or cerium oxide sol and the binder resin. The easy adhesion layer may be a single layer, but may be composed of two or more layers in order to improve adhesion.

  As the condensing layer, for example, it is processed so as to provide a structure on the microlens array on the sunlight receiving side of the support substrate, or the amount of light received from a specific direction is increased by combining with a so-called condensing sheet. Conversely, the incident angle dependency of sunlight can be reduced.

  As an example of the microlens array, quadrangular pyramids having a side of 30 μm and an apex angle of 90 degrees are two-dimensionally arranged on the light extraction side of the substrate. One side is preferably 10 to 100 μm. If it becomes smaller than this, the effect of diffraction will generate | occur | produce and color, and if too large, thickness will become thick and is not preferable.

  Examples of the light scattering layer include various antiglare layers, layers in which nanoparticles or nanowires such as metals or various inorganic oxides are dispersed in a colorless and transparent polymer, and the like.

  The layer structure of the organic photoelectric conversion element of the present invention is preferably a layer structure of the anode, the highly conductive layer, and the hole transport layer, in which the electrode having the aggregate structure of the metal fine particles constitutes an anode.

  Moreover, it is preferable that the electrode having the aggregate structure of the metal fine particles constitutes a cathode and has a layer structure of a cathode, a highly conductive layer, and an electron transport layer.

  Furthermore, an organic photoelectric conversion element having at least an anode, a highly conductive layer, a hole transport layer, a photoelectric conversion layer, an electron transport layer, a highly conductive layer, and a cathode in this order on the substrate is preferable.

(Film forming method / Surface treatment method)
Examples of the method for forming a photoelectric conversion layer in which an electron acceptor and an electron donor are mixed, and a transport layer / electrode include a vapor deposition method, a coating method (including a casting method and a spin coating method), and the like. Among these, as a formation method of a photoelectric converting layer, a vapor deposition method, the apply | coating method (a casting method, a spin coat method is included), etc. can be illustrated. Among these, the coating method is preferable in order to increase the area of the interface where holes and electrons are separated by charge and to produce a device having high photoelectric conversion efficiency. The coating method is also excellent in production speed.

  Although there is no restriction | limiting in the coating method used in this case, For example, a spin coat method, the cast method from a solution, a dip coat method, a blade coat method, a wire bar coat method, a gravure coat method, a spray coat method etc. are mentioned. Furthermore, patterning can also be performed by a printing method such as an ink jet method, a screen printing method, a relief printing method, an intaglio printing method, an offset printing method, or a flexographic printing method.

  After coating, it is preferable to perform heating in order to cause removal of residual solvent, moisture and gas, and improvement of mobility and absorption longwave due to crystallization of the semiconductor material. When annealing is performed at a predetermined temperature during the manufacturing process, a part of the particles is microscopically aggregated or crystallized and the photoelectric conversion layer can have an appropriate phase separation structure. As a result, the carrier mobility of the photoelectric conversion layer is improved and high efficiency can be obtained.

  The photoelectric conversion layer may be composed of a layer in which a p-type semiconductor and an n-type semiconductor are mixed, but may have a plurality of layers having different mixing ratios in the film thickness direction or a gradation structure with a mixing ratio.

(Patterning)
There is no particular limitation on the method and process for patterning the electrode, photoelectric conversion layer, hole transport layer, electron transport layer, recombination layer, and the like according to the present invention, and known methods can be applied as appropriate.

  If it is a soluble material such as a photoelectric conversion layer and a transport layer, only unnecessary portions may be wiped after the entire surface of die coating, dip coating, etc., or ablation using a carbonic acid laser after film formation, or scraping directly with a scriber Patterning may be performed by a method or the like, or direct patterning may be performed using various printing methods such as an inkjet method, screen printing, and gravure printing.

  In the case of insoluble materials such as electrode materials, various printing methods such as vacuum deposition method, vacuum sputtering method, plasma CVD method, screen printing method using ink in which fine particles of electrode material are dispersed, gravure printing method, inkjet method, etc. The pattern may be formed by a known method such as etching or lift-off of the deposited film, or by transferring a pattern formed on another substrate.

(Sealing)
In order to prevent the produced organic photoelectric conversion element from being deteriorated by oxygen, moisture, etc. in the atmosphere, it is preferable to seal by a known method. 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 an organic photoelectric conversion element are pasted with an adhesive. Method of coating, method of coating organic polymer material (polyvinyl alcohol etc.) with high gas barrier property, method of depositing inorganic thin film (silicon oxide, aluminum oxide etc.) or organic film (parylene etc.) with high gas barrier property under vacuum And a method of laminating these in a composite manner.

  Furthermore, in the present invention, from the viewpoint of improving energy conversion efficiency and device lifetime, the entire device may be sealed with two substrates with a barrier, and preferably a moisture getter, oxygen getter, etc. are enclosed. Is more preferred in the present invention.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.

Example 1
<< Production of organic photoelectric conversion element >>
[Production of Organic Photoelectric Conversion Element SC-105]
Organic photoelectric conversion element SC-105 was produced by the following procedure. These operations were performed under a nitrogen atmosphere unless otherwise specified.

(Transparent electrode layer)
Under the atmosphere, a silver nanoparticle paste 1 (M-Dot SLP manufactured by Mitsuboshi Belting) was placed on a PET substrate using a gravure printing tester K303MULTICOATER manufactured by RK Print Coat Instruments Ltd. with a line width of 50 μm, a height of 0.8 μm, and an interval. After printing a 1.0 mm fine wire grid, a drying process was performed at 110 ° C. for 5 minutes to produce an auxiliary electrode. A transparent electrode layer coating solution having the following composition was applied on a substrate provided with an auxiliary electrode so as to have a wet film thickness of 10 μm, and dried at 90 ° C. for 1 minute. Then, the heat processing for 30 minutes were performed at 120 degreeC using the electric furnace, and the transparent electrode layer was formed.

Transparent electrode layer coating liquid Conductive polymer dispersion (Clevios TH510; manufactured by HC Starck, solid content 1.7% by mass) 17.6 g
Water-soluble binder WP-1 aqueous solution (number average molecular weight 33700, molecular weight distribution 2.4, solid content 20% by mass) 3.5 g
Dimethyl sulfoxide 1.0g

(First electron transport layer)
On this transparent electrode, a mixed solution of polyethyleneimine dissolved in isopropanol and glycerol propoxylate triglycidyl ether is applied and dried on a hot plate at 120 ° C. for 10 minutes to form a first electron transport layer having a thickness of 5 nm. did.

(First photoelectric conversion layer)
P3HT (manufactured by Prectronics: regioregular poly-3-hexylthiophene, HOMO: -5.5 eV, LUMO: -3.4 eV) and PC60BM (manufactured by Frontier Carbon: 6,6-phenyl-C ₆₁ -butyrate) Rick Acid Methyl Ester, HOMO: -6.1 eV, LUMO: -4.3 eV) prepared at a ratio of 1: 0.8 so as to be 3.0% by mass, filtered through a filter, and dried film thickness The coating was dried to a thickness of about 200 nm to form a first electron transport layer.

(First hole transport layer)
A liquid containing PEDOT-PSS (CLEVIOS (registered trademark) PVP AI 4083, manufactured by H.C. Starck Co., Ltd., conductivity 1 × 10 ⁻³ S / cm) composed of a conductive polymer and a polyanion, and isopropanol is prepared. The coating was dried on the first photoelectric conversion layer so that the dry film thickness was about 100 nm. Thereafter, heat treatment was performed at 120 ° C. for 10 minutes to form a first hole transport layer.

(Recombination layer)
PEDOT-PSS composed of a conductive polymer and a polyanion (CLEVIOS (registered trademark) PH500, 5 mass% DMSO added to H.C. Starck Co., Ltd. (conductivity: 500 S / cm)) and a liquid containing isopropanol It was prepared and applied and dried on the first hole transport layer so that the dry film thickness was about 100 nm. Thereafter, a heat treatment was performed at 120 ° C. for 10 minutes to form a recombination layer.

(Second electron transport layer)
The following ET-1 was dissolved in butanol and coated on the recombination layer, and then irradiated with 365 nm UV light at an irradiation energy of 3 J / cm ² for 3 minutes. Then, it heated at 80 degreeC for 10 minute (s) on the hotplate, and formed the 2 nm thickness 2nd electron carrying layer.

(Second photoelectric conversion layer)
A liquid obtained by mixing the following PCPDTBT and PC70BM (manufactured by Frontier Carbon Co., Ltd .: 6,6-phenyl-C ₇₁ -butyric acid methyl ester) as a photoelectric conversion layer polymer at 1: 1.5 so as to be 3.0% by mass. It prepared, filtered with the filter, and apply | coated and dried so that the dry film thickness might be set to about 100 nm on the 2nd electron carrying layer, and the 2nd photoelectric converting layer was formed.

(Second hole transport layer)
A liquid containing PEDOT-PSS (CLEVIOS (registered trademark) PVP AI 4083, manufactured by H.C. Starck Co., Ltd., conductivity 1 × 10 ⁻³ S / cm) composed of a conductive polymer and a polyanion, and isopropanol is prepared. The coating was dried on the second photoelectric conversion layer so that the dry film thickness was about 100 nm. Thereafter, heat treatment was performed at 120 ° C. for 10 minutes to form a second hole transport layer.

(electrode)
Then, 150 nm of silver was vapor-deposited with the vapor deposition machine, and organic photoelectric conversion element SC-105 was produced.

[Production of Organic Photoelectric Conversion Element SC-101]
Lamination was performed up to the first photoelectric conversion layer in the same manner as in the organic photoelectric conversion element SC-105, and then, 1 nm of silver was evaporated under a vacuum of 10 ⁻⁶ Pa with a vapor deposition machine to form a recombination layer. Then, it returned to under nitrogen from the vacuum, and formed the 2nd photoelectric converting layer after the organic photoelectric conversion element SC-105 similarly.

[Production of Organic Photoelectric Conversion Element SC-102]
Lamination is performed up to the first photoelectric conversion layer in the same manner as the organic photoelectric conversion element SC101, and then MoO ₃ is deposited in a thickness of 5 nm under a vacuum of 10 ⁻⁶ Pa by a vapor deposition machine to form a first hole transport layer, and silver is added. A recombination layer was formed by vapor deposition of 1 nm. Thereafter, the vacuum was returned to the atmosphere, and ZnO was applied by a sol-gel method to form a second electron transport layer having a dry film thickness of 10 nm. Thereafter, the second and subsequent photoelectric conversion layers were formed in the same manner as in the organic photoelectric conversion element SC-105.

[Production of Organic Photoelectric Conversion Element SC-103]
Lamination was performed up to the first hole transport layer in the same manner as in the organic photoelectric conversion element SC101, and then, 1 nm of silver was deposited under a vacuum of 10 ⁻⁶ Pa by a vapor deposition machine to form a recombination layer. Then, it returned to under nitrogen from the vacuum, and formed the 2nd electron carrying layer or later similarly to organic photoelectric conversion element SC-105.

[Production of Organic Photoelectric Conversion Element SC-104]
Lamination was performed up to the first hole transport layer in the same manner as in the organic photoelectric conversion element SC101, and then 1 nm of aluminum was deposited under a vacuum of 10 ⁻⁶ Pa with a vapor deposition machine to form a recombination layer. Then, it returned to under nitrogen from the vacuum, and formed the 2nd electron carrying layer or later similarly to organic photoelectric conversion element SC-105.

[Production of Organic Photoelectric Conversion Elements SC-106 to 113]
In the production of the organic photoelectric conversion element SC101, the organic photoelectric conversion elements SC-106 to 113 are similarly formed except that the first hole transport layer, the recombination layer, and the second electron transport layer are changed as shown in Table 1. Produced.

  In addition, the material used for the recombination layer was displayed with the following abbreviations.

PH500 + DMSO: PEDOT-PSS (CLEVIOS (registered trademark) PH500, 5 mass% DMSO added to HC Starck Co., Ltd. 5% by mass DMSO added PH500: PEDOT-PSS (CLEVIOS (registered trademark) PH500, manufactured by H.C. Starck Co., Ltd. PH: PEDOT-PSS (CLEVIOS (registered trademark) PH, manufactured by H.C. Stark Co., Ltd. P4083: PEDOT-PSS (CLEVIOS (registered trademark) P VP AI 4083, manufactured by HC Starck Co., Ltd.)

<< Evaluation of organic photoelectric conversion element >>
An organic photoelectric conversion device prepared above, was irradiated with light having an intensity of 100 mW / cm ² solar simulator (AM1.5G filter), a superposed mask in which the effective area to 1 cm ² on the light receiving unit, to evaluate the IV characteristics Then, the four light receiving portions formed on the same element were measured for the short-circuit current density Jsc (mA / cm ² ), the open circuit voltage Voc (V), and the fill factor FF. Next, the photoelectric conversion efficiency η (%) was obtained from the average values of Jsc, Voc, and FF according to Equation 1.

Formula 1 η (%) = Jsc (mA / cm ² ) × Voc (V) × FF (%)
Moreover, the organic photoelectric conversion element produced here was heated at 85 degreeC for 500 hours, Then, IV characteristic was evaluated and thermal stability was evaluated.

  The evaluation results are shown in Table 2.

  From Table 2, the organic photoelectric conversion elements SC-105 to 112 of the present invention can form electrodes by a coating process under normal pressure having high productivity, and have high photoelectric conversion efficiency and high thermal stability. The effect of the invention became clear.

Example 2
<< Production of organic photoelectric conversion element >>
[Production of Organic Photoelectric Conversion Element SC-205]
An organic photoelectric conversion element SC-205 was produced by the following procedure. These operations were performed under a nitrogen atmosphere unless otherwise specified.

(First hole transport layer)
On the transparent electrode produced in Example 1, PEDOT-PSS (CLEVIOS (registered trademark) PVP AI 4083, manufactured by H.C. Starck Co., Ltd., made of conductive polymer and polyanion, conductivity 1 × 10 ⁻³ S / Cm), a solution containing isopropanol was prepared and applied and dried so that the dry film thickness was about 80 nm. Thereafter, heat treatment was performed at 120 ° C. for 10 minutes to form a first hole transport layer.

(First photoelectric conversion layer)
As a photoelectric conversion layer polymer, a liquid prepared by mixing PCPDTBT and PC70BM (manufactured by Frontier Carbon Co., Ltd .: 6,6-phenyl-C ₇₁ -butyric acid methyl ester) at 1: 1.5 so as to be 3.0% by mass is prepared. And it filtered with the filter and formed the 1st photoelectric converting layer so that the dry film thickness might be set to about 80 nm on the 1st positive hole transport layer.

(First electron transport layer)
PFN-OH was dissolved in butanol, applied onto the first photoelectric conversion layer, and heated at 80 ° C. for 10 minutes to form a first electron transport layer having a thickness of 20 nm.

(Recombination layer)
A liquid containing PEDOT-PSS (CLEVIOS (registered trademark) PH500, manufactured by H.C. Starck Co., Ltd., 5% by mass DMSO (conductivity: 500 S / cm)) and isopropanol composed of a conductive polymer and a polyanion. It was prepared, applied and dried on the first electron transport layer so that the dry film thickness was about 100 nm. Thereafter, a heat treatment was performed at 120 ° C. for 10 minutes to form a recombination layer.

(Second hole transport layer)
A liquid containing PEDOT-PSS (CLEVIOS (registered trademark) PVP AI 4083, manufactured by H.C. Starck Co., Ltd., conductivity 1 × 10 ⁻³ S / cm) composed of a conductive polymer and a polyanion, and isopropanol is prepared. On the recombination layer, it was applied and dried so that the dry film thickness was about 100 nm. Thereafter, heat treatment was performed at 120 ° C. for 10 minutes to form a first hole transport layer.

(Second photoelectric conversion layer)
P3HT (manufactured by Prectronics: regioregular poly-3-hexylthiophene, HOMO: -5.5 eV, LUMO: -3.4 eV) and PC60BM (manufactured by Frontier Carbon: 6,6-phenyl-C ₆₁ -butyrate) Rick Acid Methyl Ester, HOMO: -6.1 eV, LUMO: -4.3 eV) was prepared at a ratio of 1: 0.8 so as to be 3.0% by mass, and filtered to obtain a dry film thickness. The coating film was dried to a thickness of about 200 nm to form a second photoelectric conversion layer.

(Second electron transport layer)
Similarly to the first electron transport layer, ET-2 was dissolved in butanol, applied and dried on the second photoelectric conversion layer, and heated at 80 ° C. for 10 minutes to form a second electron transport layer having a thickness of 50 nm. .

(electrode)
Then, 150 nm of aluminum was vapor-deposited with the vapor deposition machine, and organic photoelectric conversion element SC-205 was produced.

[Production of Organic Photoelectric Conversion Element SC-201]
Lamination was performed up to the first photoelectric conversion layer in the same manner as in the organic photoelectric conversion element SC205, and then TiOx was applied by the method of Non-Patent Document 3 in the atmosphere to form a first electron transport layer. Then, it returned to nitrogen and formed the recombination layer after the organic photoelectric conversion element SC-205 similarly.

[Production of Organic Photoelectric Conversion Elements SC-202 to 204, 206 to 208]
In the production of the organic photoelectric conversion element SC205, the organic photoelectric conversion elements SC-202 to 204, 206 were similarly performed except that the first hole transport layer, the recombination layer, and the second transport layer were changed as shown in Table 3. -208 were made.

<< Evaluation of organic photoelectric conversion element >>
About the produced organic photoelectric conversion element, it evaluated similarly to Example 1. FIG.

  The evaluation results are shown in Table 2.

  From Table 4, the organic photoelectric conversion elements SC-202 to 204 and 206 to 208 of the present invention can form electrodes by a coating process under normal pressure having high productivity, have high photoelectric conversion efficiency, and are thermally stable. The effect of this invention became clear.

10, 20 Organic photoelectric conversion device 100 Substrate 101 First electrode (transparent electrode, cathode)
102 1st electron transport layer 103 1st photoelectric converting layer 104 1st hole transport layer 105 recombination layer 106 2nd electron transport layer 107 2nd photoelectric converting layer 108 2nd hole transport layer 109 2nd electrode (anode)
201 1st electrode (transparent electrode, anode)
209 Second electrode (cathode)

Claims (3)

  A tandem organic photoelectric conversion element having at least two photoelectric conversion layers, wherein 70% by mass of organic matter is present between at least one pair of adjacent photoelectric conversion layers among the two or more photoelectric conversion layers. An organic photoelectric sensor characterized by having at least one recombination layer and a charge transport layer that selectively transports electrons or holes, and the recombination layer has a conductivity of 5 to 50,000 S / cm. Conversion element.   The organic photoelectric conversion element according to claim 1, wherein the electrical conductivity of the recombination layer is 10 to 10,000 S / cm. The electrical conductivity of a charge transport layer (hole transport layer) that selectively transports holes among the charge transport layers is 10 ^{−5 to 1} S / cm. 4. Organic photoelectric conversion element.

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