WO2013172175A1 - Photovoltaic element - Google Patents

Photovoltaic element Download PDF

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Publication number
WO2013172175A1
WO2013172175A1 PCT/JP2013/062229 JP2013062229W WO2013172175A1 WO 2013172175 A1 WO2013172175 A1 WO 2013172175A1 JP 2013062229 W JP2013062229 W JP 2013062229W WO 2013172175 A1 WO2013172175 A1 WO 2013172175A1
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photoelectric conversion
electron
layer
extraction layer
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PCT/JP2013/062229
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French (fr)
Japanese (ja)
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下村悟
山本修平
北澤大輔
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東レ株式会社
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    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K85/00—Organic materials used in the body or electrodes of devices covered by this subclass
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K30/00—Organic devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation
    • H10K30/30—Organic devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation comprising bulk heterojunctions, e.g. interpenetrating networks of donor and acceptor material domains
    • H10K30/353—Organic devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation comprising bulk heterojunctions, e.g. interpenetrating networks of donor and acceptor material domains comprising blocking layers, e.g. exciton blocking layers
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K85/00—Organic materials used in the body or electrodes of devices covered by this subclass
    • H10K85/10—Organic polymers or oligomers
    • H10K85/111—Organic polymers or oligomers comprising aromatic, heteroaromatic, or aryl chains, e.g. polyaniline, polyphenylene or polyphenylene vinylene
    • H10K85/113—Heteroaromatic compounds comprising sulfur or selene, e.g. polythiophene
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K85/00—Organic materials used in the body or electrodes of devices covered by this subclass
    • H10K85/10—Organic polymers or oligomers
    • H10K85/111—Organic polymers or oligomers comprising aromatic, heteroaromatic, or aryl chains, e.g. polyaniline, polyphenylene or polyphenylene vinylene
    • H10K85/115—Polyfluorene; Derivatives thereof
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K85/00—Organic materials used in the body or electrodes of devices covered by this subclass
    • H10K85/10—Organic polymers or oligomers
    • H10K85/151—Copolymers
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy
    • Y02E10/549—Organic PV cells

Definitions

  • the present invention relates to a photovoltaic device.
  • Solar cells are attracting attention as an environmentally friendly electrical energy source and an influential energy source for increasing energy problems.
  • inorganic materials such as single crystal silicon, polycrystalline silicon, amorphous silicon, and compound semiconductors are used as semiconductor materials for photovoltaic elements of solar cells.
  • solar cells manufactured using inorganic semiconductors have not been widely used in ordinary households because of high costs compared with power generation methods such as thermal power generation and nuclear power generation.
  • the high cost factor is mainly in the process of forming the semiconductor thin film under vacuum and high temperature. Therefore, organic semiconductor cells using organic semiconductors such as conjugated polymers and organic crystals and organic dyes are being studied as semiconductor materials that are expected to simplify the manufacturing process.
  • a semiconductor material can be manufactured by a coating method, so that the manufacturing process can be simplified.
  • Examples of a method for improving the photoelectric conversion efficiency of an organic solar cell include a method of providing an electron extraction layer between a photoelectric conversion layer composed of a laminated film of copper phthalocyanine and fullerene and a silver cathode. By this method, conversion efficiency is improved, for example, by suppressing deterioration of the photoelectric conversion layer due to silver cathode deposition. And, it has been studied to use a polymer material into which an ionic group is introduced in the electron extraction layer of the organic solar cell.
  • Non-patent Document 1 a substituted fluorene polymer into which ammonium acetate is introduced
  • Non-patent Document 2 a substituted fluorene polymer into which ammonium bromide salt is introduced
  • Non-patent Document 4 a substituted fluorene into which ammonium bromide salt is introduced
  • Conversion efficiency is improved by using polyethylene oxide (Non-patent Document 4), which is a combination of a polymer based and a substituted thiophene polymer (Non-patent Document 3) and ammonium acetate, as an electron extraction layer of an organic solar cell.
  • the insulating properties increase, which causes a decrease in device characteristics, and the adaptive film thickness of these polymer materials is limited to 5 nm or less.
  • the electron extraction layer having a large surface roughness does not function sufficiently, and high photoelectric conversion efficiency may not be obtained after all.
  • the present invention provides an electron extraction layer that realizes a high photoelectric conversion efficiency improvement effect by using an organic material that is easier to synthesize, that is, inexpensive, and has a wide adaptive film thickness range as the electron extraction layer.
  • An object of the present invention is to provide a photovoltaic device having the same.
  • the inventors focused on the molecular weight of a compound into which an ionic group was introduced, as described above, in view of the above problems.
  • a specific ionic group is introduced and a compound having the ionic group introduced is made to have a specific molecular weight
  • the degree of freedom in molecular orientation is increased and the charge is more easily transferred. I was able to find out.
  • a photovoltaic device having excellent photoelectric conversion efficiency can be obtained by using a compound having a specific molecular weight introduced with such a specific ionic group in the electron extraction layer.
  • the present invention is a photovoltaic device having at least an anode, a photoelectric conversion layer, an electron extraction layer, and a cathode in this order, and the electron extraction layer has the following general formulas (1) to (1) having a molecular weight of 10,000 or less. 3) A photovoltaic device comprising at least one compound group represented by 3).
  • R 1 to R 11 may be the same or different, and may be hydrogen, a hydrocarbon group that may have a substituent, or at least oxygen, nitrogen, phosphorus, silicon, and boron that may have a substituent.
  • a group containing one element selected from the above and a heterocyclic group which may have a substituent, provided that R 5 and R 8 are not hydrogen, and R 1 to R 11 are A 1 to A 3 may be selected from nitrogen and phosphorus, and B 1 ⁇ and B 2 ⁇ may be F ⁇ , which may be independent from each other or bonded to each other to form a ring.
  • a photovoltaic device with high photoelectric conversion efficiency can be provided.
  • the photovoltaic element of the present invention is a photovoltaic element having at least an anode, a photoelectric conversion layer, an electron extraction layer, and a cathode in this order, and the electron extraction layer has the following general formula (1) having a molecular weight of 10,000 or less. It includes at least one of the compound groups represented by (3) to (3).
  • R 1 to R 11 may be the same or different, and may be hydrogen, a hydrocarbon group that may have a substituent, or at least oxygen, nitrogen, phosphorus, silicon, and boron that may have a substituent.
  • a group containing one element selected from the above and a heterocyclic group which may have a substituent, provided that R 5 and R 8 are not hydrogen, and R 1 to R 11 are A 1 to A 3 may be selected from nitrogen and phosphorus, and B 1 ⁇ and B 2 ⁇ may be F ⁇ , which may be independent from each other or bonded to each other to form a ring.
  • the molecular weight here refers to the molecular weight when the compounds represented by the above general formulas (1) to (3) have no distribution in the molecular weight, and the weight average molecular weight when there is a distribution. .
  • the molecular weight of the electron extraction layer material of the present invention is 10,000 or less. Accordingly, the solubility in a solvent is improved and the degree of freedom of molecular orientation is ensured. Therefore, the charge can easily move through the electron extraction layer, and the charge extraction efficiency can be improved. Although it will not specifically limit if the molecular weight of electron extraction layer material is 10,000 or less, Preferably, it is 2000 or less, More preferably, it is 1000 or less.
  • the hydrocarbon group which may have a substituent is an alkyl group, an alkylidene group, a cycloalkyl group, an alkenyl group, an alkynyl group, or an aryl group It is.
  • the hydrocarbon group of the hydrocarbon group that may have a substituent is an alkyl chain, an alkylidene chain, a cycloalkyl chain, an alkenyl chain, an alkynyl chain, and an aryl chain.
  • an alkyl chain is an alkyl group
  • an alkylidene chain is an alkylidene group
  • a cycloalkyl chain is a cycloalkyl group
  • an alkenyl chain is an alkenyl group
  • an alkynyl chain is an alkynyl group
  • an aryl chain is an aryl group.
  • the alkyl group represents a saturated aliphatic hydrocarbon group such as a methyl group, an ethyl group, a propyl group, or a butyl group.
  • An alkylidene group refers to a group in which two bonds of an alkylene group are bonded to the same atom, such as a methylidene group.
  • the cycloalkyl group represents a cyclic saturated aliphatic hydrocarbon group such as a cyclopropyl group, a cyclobutyl group, or a cyclopentyl group.
  • an alkenyl group shows the unsaturated aliphatic hydrocarbon group which has a double bond, such as a vinyl group, a propenyl group, and a butenyl group.
  • an alkynyl group shows the unsaturated aliphatic hydrocarbon group which has triple bonds, such as an ethynyl group, a propynyl group, and a butynyl group.
  • the aryl group represents, for example, an aromatic hydrocarbon group such as phenyl, naphthyl, biphenyl, phenanthryl, anthryl, terphenyl, pyrenyl, fluorenyl, perylenyl, indenyl, and azulenyl.
  • substituents in the case of having a substituent include the alkyl group, alkylidene group, cycloalkyl group, alkenyl group, alkynyl group, aryl group, heterocyclic group, halogen atom, hydroxyl group, cyano group, azide group, and nitrile group. , Alkoxy groups, sulfide groups, disulfide groups, amino groups, azo groups, phosphoryl groups, phosphate ester groups, sulfonyl groups, carbonyl groups, silyl groups, boryl groups, and combinations thereof.
  • At least one selected from oxygen, nitrogen, silicon and boron in a group containing at least one element selected from oxygen, nitrogen, phosphorus, silicon and boron which may have a substituent
  • the group containing an element represents a substituent and a carbonyl group that are substituted via one element selected from oxygen, nitrogen, phosphorus, silicon, and boron.
  • substituent substituted through one element selected from oxygen, nitrogen, phosphorus, silicon, and boron include, for example, an alkoxy group, a sulfide group, a disulfide group, an amino group, an azo group, a phosphoryl group, and phosphoric acid.
  • Examples thereof include an ester group, a sulfonyl group, a silyl group, and a boryl group.
  • the sulfonyl group includes a thioester group and the like.
  • the carbonyl group includes an ester group, a carboxyl group, an acyl group, and the like.
  • the heterocyclic group of the heterocyclic group which may have a substituent is an epoxy group, aziridyl group, episulfide group, oxolanyl group, pyrrolidinyl group, thiolanyl group, oxanyl group, piperidinyl group, thianyl group, pyridyl group , Thienyl group, furyl group, pyrrolyl group, oxazolyl group, thiazolyl group, oxadiazolyl group, thiadiazolyl group, pyrazyl group, pyrimidyl group, pyrazolyl group, imidazolyl group, benzothienyl group, benzodithienyl group, dibenzofuryl group, dibenzothienyl group , Phenylcarbazolyl group, phenoxathienyl group, xanthenyl group, benzofuranyl group, thiantenyl group, indolizin
  • R 1 to R 4 , R 7 and R 9 to R 11 are alkyl groups, R 8 Is preferably an alkyl chain.
  • the total number of carbon atoms of R in the same molecule is more preferably 5 or more, and more preferably 16 or more.
  • R 1 to R 11 may be independent from each other or may be bonded to each other to form a ring, but R 5 and R 6 may be bonded to each other to form a ring. preferable. Among these, it is more preferable that R 5 and R 6 form a 6-membered ring.
  • R 1 to R 11 specific substituents represented by R 1 to R 11 are exemplified.
  • the exemplified substituents are part of the present invention and are not particularly limited thereto.
  • a single line and a double line extending horizontally to the left indicate the bonding positions of the substituents.
  • description may be abbreviate
  • a 1 to A 3 are selected from nitrogen or phosphorus which exists as a soft acid having a small charge density and can form a stable ion pair. Nitrogen that is less susceptible to oxidation reaction and forms more stable ions is preferable.
  • B 1 ⁇ , B 2 ⁇ represents F ⁇ , Cl ⁇ , Br ⁇ , I ⁇ , OH ⁇ , BF 4 ⁇ , PF 6 ⁇ , ClO 4 ⁇ , NO 3 ⁇ , CN ⁇ , SCN ⁇ , HPO 4 ⁇ , It is a counter ion selected from PO 4 2 ⁇ , SO 4 2 ⁇ , CO 3 2 ⁇ , carboxylate anion, and sulfonate anion.
  • Cl ⁇ and Br ⁇ are preferable, and Br ⁇ is more preferable.
  • X 1 — is selected from —COO ⁇ , —SO 3 ⁇ , —PO 4 H ⁇ , —PO 4 2 ⁇ , —O—SO 3 — .
  • —SO 3 ⁇ and —COO ⁇ are preferable.
  • Examples of the compound represented by the general formula (1) include the following structures.
  • Examples of the compound represented by the general formula (2) include the following structures.
  • Examples of the compound represented by the general formula (3) include the following structures.
  • the compound represented by the general formula (1) is preferable because it has excellent film forming properties and realizes higher electron extraction efficiency.
  • FIG. 1 is a cross-sectional view showing one embodiment of the photovoltaic device of the present invention.
  • an anode 2 On a substrate 1, an anode 2, a photoelectric conversion layer 3, an electron extraction layer 4 including a compound group represented by the general formulas (1) to (3), and a cathode 5 are provided in this order.
  • a substrate on which an electrode or a photoelectric conversion layer can be stacked can be selected and used.
  • films made by any method from inorganic materials such as alkali-free glass and quartz glass, organic materials such as polyester, polycarbonate, polyolefin, polyamide, polyimide, polyphenylene sulfide, polyparaxylene, epoxy resin and fluorine resin A board can be used.
  • the light transmittance of the substrate is preferably 60-100%.
  • the light transmittance is [Transmission light intensity (W / m 2 ) / incident light intensity (W / m 2 )] ⁇ 100 (%) The value given by.
  • the anode or cathode of the photovoltaic element of the present invention has light transparency. It is sufficient that at least one of them has optical transparency, and both of them may have optical transparency.
  • having light transparency means that incident light reaches the photoelectric conversion layer and an electromotive force is generated. That is, when the light transmittance exceeds 0%, it is said to have light transmittance.
  • the light-transmitting electrode preferably has a light transmittance of 60 to 100% in all wavelength regions of 400 nm to 900 nm. Further, the thickness of the light-transmitting electrode is not limited as long as sufficient conductivity is obtained and varies depending on the material, but is preferably 20 nm to 300 nm. In addition, the electrode which does not have a light transmittance should just be electroconductive, and thickness is not specifically limited, either.
  • the electrode material it is preferable to use a conductive material having a high work function for the anode and a conductive material having a low work function for the other cathode.
  • Conductive materials with large work functions include metals such as gold, platinum, chromium and nickel, transparent metal oxides such as indium and tin, and complex metal oxides (indium tin oxide (ITO), indium zinc oxide) Products (IZO) and the like, and conductive polymers are preferably used.
  • the anode preferably has a hole extraction layer. An interface state suitable for extracting carriers can be formed by the hole extraction layer. Furthermore, there is an effect of preventing a short circuit between the electrodes.
  • a conductive polymer such as a polythiophene polymer containing a dopant, a poly-p-phenylene vinylene polymer, a polyfluorene polymer, or a metal oxide such as molybdenum oxide may be used.
  • a conductive polymer such as a polythiophene polymer containing a dopant, a poly-p-phenylene vinylene polymer, a polyfluorene polymer, or a metal oxide such as molybdenum oxide may be used.
  • the polythiophene polymer, the poly-p-phenylene vinylene polymer, and the polyfluorene polymer refer to polymers having a thiophene skeleton, a p-phenylene vinylene skeleton, and a fluorene skeleton in the main chain, respectively.
  • molybdenum oxide or a polythiophene polymer such as polyethylenedioxythiophene (PEDOT) containing a dopant, particularly a mixture of PEDOT and polystyrene sulfonate (PSS) is more preferable.
  • the hole extraction layer may be formed by laminating a plurality of these materials, and the materials to be laminated may be different.
  • alkali metals such as lithium, alkaline earth metals such as magnesium and calcium, tin, silver, and aluminum are preferably used.
  • an electrode made of an alloy made of the above metal or a laminate of the above metal is also preferably used.
  • the cathode may contain a metal fluoride such as lithium fluoride and cesium fluoride.
  • the photoelectric conversion layer in the photovoltaic device of the present invention is sandwiched between the anode and the cathode and includes at least (A) an electron-donating organic semiconductor and (B) an electron-accepting organic semiconductor, which will be described later.
  • a layer composed of a mixture of an electron-donating organic semiconductor and an electron-accepting organic semiconductor a structure in which a layer composed of an electron-donating organic semiconductor and a layer composed of an electron-accepting organic semiconductor, a layer composed of an electron-donating organic semiconductor, The structure etc. which laminated
  • the electron donating organic semiconductor and the electron accepting organic semiconductor preferably form a mixed layer.
  • the content ratio of the electron-donating organic semiconductor and the electron-accepting organic semiconductor in the photoelectric conversion layer is not particularly limited, but the weight ratio of electron-donating organic semiconductor: electron-accepting organic semiconductor is in the range of 1 to 99:99 to 1. It is preferably in the range of 10 to 90:90 to 10, more preferably in the range of 20 to 60:80 to 40.
  • the photoelectric conversion layer only needs to have a thickness sufficient for (A) the electron-donating organic semiconductor and (B) the electron-accepting organic semiconductor to generate a photovoltaic force by light absorption. Although it varies depending on the material, a thickness of 10 nm to 1000 nm is preferable, and 50 nm to 500 nm is more preferable.
  • the photoelectric conversion layer in the present invention may contain other components such as a surfactant, a binder resin, and a filler as long as the object of the present invention is not impaired.
  • An electron donating organic semiconductor will not be specifically limited if it is an organic substance which shows a p-type semiconductor characteristic.
  • polythiophene polymer 2,1,3-benzothiadiazole-thiophene copolymer, quinoxaline-thiophene copolymer, thiophene-benzodithiophene copolymer, poly-p-phenylene vinylene polymer, Conjugated polymers such as poly-p-phenylene polymer, polyfluorene polymer, polypyrrole polymer, polyaniline polymer, polyacetylene polymer, polythienylene vinylene polymer, H 2 phthalocyanine (H 2 Pc), phthalocyanine derivatives such as copper phthalocyanine (CuPc), zinc phthalocyanine (ZnPc), porphyrin derivatives, N, N′-diphenyl-N, N′-di (3-methylphenyl) -4,4′-diphenyl-1
  • the polythiophene polymer refers to a conjugated polymer having a thiophene skeleton in the main chain, and includes those having a side chain.
  • poly-3-alkylthiophene such as poly-3-methylthiophene, poly-3-butylthiophene, poly-3-hexylthiophene, poly-3-octylthiophene, poly-3-decylthiophene, poly- Poly-3-alkoxythiophene such as 3-methoxythiophene, poly-3-ethoxythiophene, poly-3-dodecyloxythiophene, poly-3-methoxy-4-methylthiophene, poly-3-dodecyloxy-4-methylthiophene And poly-3-alkoxy-4-alkylthiophene.
  • the 2,1,3-benzothiadiazole-thiophene copolymer refers to a conjugated copolymer having a thiophene skeleton and a 2,1,3-benzothiadiazole skeleton in the main chain.
  • Specific examples of the 2,1,3-benzothiadiazole-thiophene copolymer include the following structures. In the following formula, n represents a range of 1 to 1000.
  • the quinoxaline-thiophene copolymer refers to a conjugated copolymer having a thiophene skeleton and a quinoxaline skeleton in the main chain.
  • Specific examples of the quinoxaline-thiophene copolymer include the following structures. In the following formula, n represents a range of 1 to 1000.
  • the thiophene-benzodithiophene polymer refers to a conjugated copolymer having a thiophene skeleton and a benzodithiophene skeleton in the main chain.
  • Specific examples of the thiophene-benzodithiophene copolymer include the following structures. In the following formula, n represents a range of 1 to 1000.
  • the poly-p-phenylene vinylene polymer refers to a conjugated polymer having a p-phenylene vinylene skeleton in the main chain, and includes those having a side chain. Specifically, poly [2-methoxy-5- (2-ethylhexyloxy) -1,4-phenylenevinylene], poly [2-methoxy-5- (3 ′, 7′-dimethyloctyloxy) -1, 4-phenylene vinylene] and the like.
  • the electron-accepting organic semiconductor is not particularly limited as long as it is an organic substance exhibiting n-type semiconductor characteristics.
  • fullerene derivative examples include unsubstituted ones such as C 60 , C 70 , C 76 , C 78 , C 82 , C 84 , C 90 , C 94 , and [6,6] -phenyl C61 Rick acid methyl ester ([6,6] -C61-PCBM, or [60] PCBM), [5,6] -phenyl C61 butyric acid methyl ester, [6,6] -phenyl C61 butyric acid hexyl ester, Examples thereof include substituted derivatives such as [6,6] -phenyl C61 butyric acid dodecyl ester and phenyl C71 butyric acid methyl ester ([70] PCBM). Among these, [70] PCBM is more preferable.
  • the photovoltaic device of the present invention has an electron extraction layer containing a compound group represented by the general formulas (1) to (3).
  • the electron extraction layer is characterized by not only being able to realize higher electron extraction efficiency than the conventional one but also having a wide range of applicable film thicknesses.
  • the electron extraction layer described in Non-Patent Document 2 having a molecular weight of 14,000, when the film thickness exceeds about 2.5 nm, it functions as an insulating layer, and the photoelectric conversion efficiency is significantly reduced.
  • the layer exhibits excellent electron extraction properties even at a film thickness of about 20 nm. Thereby, even a photoelectric conversion layer having a large surface roughness is excellent in that the surface can be smoothed and high photoelectric conversion efficiency can be realized.
  • the electron extraction layer may contain substances other than the compounds represented by the general formulas (1) to (3) as long as the effects of the present invention are not impaired.
  • an electron transporting organic material such as a phenanthroline monomer compound (basocuproin (BCP)) that has been conventionally used in a charge transport layer or the like.
  • BCP basic cuproin
  • a substance that does not have an electron transporting property may be included as long as the extraction of electrons from the photoelectric conversion layer to the cathode is not significantly prevented.
  • These substances other than the compound groups represented by the general formulas (1) to (3) may form a mixed layer with the compound groups represented by the general formulas (1) to (3) or may be laminated. It may be a structure.
  • the content ratio of the compound groups represented by the general formulas (1) to (3) in the electron extraction layer is not particularly limited, but is preferably in the range of 1 to 99% by weight. More preferably, it is in the range of 10 to 99%.
  • the electron extraction layer may be set to an optimum film thickness as appropriate according to the desired photoelectric conversion efficiency of the photovoltaic device, but preferably has a thickness of 0.1 nm to 50 nm, more preferably 0.5 nm to 10 nm. It is.
  • two or more photoelectric conversion layers may be laminated (tandemized) via one or more charge recombination layers to form a series junction.
  • a laminated structure of substrate / anode / first photoelectric conversion layer / first electron extraction layer / charge recombination layer / second photoelectric conversion layer / second electron extraction layer / cathode can be given.
  • the open circuit voltage can be improved.
  • the hole extraction layer described above may be provided between the anode and the first photoelectric conversion layer and between the charge recombination layer and the second photoelectric conversion layer.
  • the hole extraction layer described above may be provided between the coupling layers and between the second photoelectric conversion layer and the cathode.
  • the charge recombination layer used here needs to have light transmittance so that a plurality of photoelectric conversion layers can absorb light.
  • the charge recombination layer need only be designed so that holes and electrons are sufficiently recombined. Therefore, the charge recombination layer does not necessarily have to be a film, for example, a metal cluster uniformly formed on the photoelectric conversion layer. It doesn't matter. Therefore, the charge recombination layer is a very thin metal having a light transmittance of about several angstroms to several tens of angstroms made of the above-mentioned gold, platinum, chromium, nickel, lithium, magnesium, calcium, tin, silver, aluminum, etc.
  • Metal clusters including alloys
  • ITO indium gallium
  • IZO indium gallium
  • AZO n-doped gallium
  • GZO gallium-doped gallium
  • FTO highly transparent metal oxide films and clusters
  • titanium oxide and molybdenum oxide titanium oxide and molybdenum oxide
  • conductive organic materials such as PEDOT with PSS added
  • a material film or a composite of these is used.
  • a uniform silver cluster can be formed by depositing silver so as to have a thickness of several angstroms to 1 nm on a quartz oscillator film thickness monitor using a vacuum deposition method.
  • the sol-gel method described in Advanced Materials, 2006, Vol. 18, 572-576 may be used.
  • the film may be formed by sputtering.
  • These charge recombination layer formation methods and types may be appropriately selected in consideration of the non-destructive property to the photoelectric conversion layer at the time of charge recombination layer formation, the formation method of the next photoelectric conversion
  • a transparent electrode such as ITO (corresponding to an anode in this case) is formed on the substrate by sputtering or the like.
  • a photovoltaic device material containing an electron-donating organic semiconductor material and an electron-accepting organic material is dissolved in a solvent to form a solution, which is applied on the transparent electrode to form a photoelectric conversion layer.
  • the solvent used at this time is preferably an organic solvent, for example, methanol, ethanol, butanol, toluene, xylene, o-chlorophenol, acetone, ethyl acetate, ethylene glycol, tetrahydrofuran, dichloromethane, chloroform, dichloroethane, chlorobenzene, dichlorobenzene, Examples include chlorobenzene, chloronaphthalene, dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, and ⁇ -butyrolactone. Two or more of these may be used.
  • organic solvent for example, methanol, ethanol, butanol, toluene, xylene, o-chlorophenol, acetone, ethyl acetate, ethylene glycol, tetrahydrofuran, dichloromethane, chloroform, dichloroethane, chlorobenzene, dichlorobenzene
  • phase separation structure of the electron-donating organic semiconductor material and the electron-accepting organic material in the photoelectric conversion layer can be changed by adding an appropriate additive to the solvent.
  • the additive include thiol compounds such as 1,8-octanedithiol and iodo compounds such as 1,8-diiodooctane.
  • the photoelectric conversion layer is formed by mixing the electron-donating organic material and the electron-accepting organic material of the present invention
  • the electron-donating organic material and the electron-accepting organic material of the present invention are added to the solvent in a desired ratio. Then, the solution is dissolved by using a method such as heating, stirring and ultrasonic irradiation, and applied onto the transparent electrode.
  • a method such as heating, stirring and ultrasonic irradiation
  • a solution of the electron donating organic material of the present invention is applied to have the electron donating organic material.
  • a solution of the electron-accepting organic material is applied to form the layer.
  • the electron-donating organic material and the electron-accepting organic material of the present invention are low molecular weight substances having a molecular weight of about 1000 or less, it is also possible to form a layer using a vapor deposition method.
  • This method may be used, and the formation method may be selected according to the characteristics of the photoelectric conversion layer to be obtained, such as film thickness control and orientation control.
  • the electron donating organic material of the present invention and the electron accepting organic material have a concentration of 1 to 20 g / L (the electron donating organic material, the electron accepting organic material and the solvent of the present invention).
  • the weight of the electron-donating organic material and the electron-accepting organic material of the present invention with respect to the volume of the solution containing is preferable, and a homogeneous photoelectric conversion layer having a thickness of 5 to 200 nm can be obtained by using this concentration. Can do.
  • the formed photoelectric conversion layer may be subjected to an annealing treatment under reduced pressure or under an inert atmosphere (nitrogen or argon atmosphere).
  • a preferable temperature for the annealing treatment is 40 ° C to 300 ° C, more preferably 50 ° C to 200 ° C. This annealing treatment may be performed after the formation of the cathode.
  • an electron extraction layer material containing the compounds represented by the general formulas (1) to (3) is dissolved in a solvent to form a solution, and an electron extraction layer is formed on the photoelectric conversion layer.
  • the solvent used at this time is preferably an organic solvent, for example, methanol, ethanol, butanol, toluene, xylene, o-chlorophenol, acetone, ethyl acetate, ethylene glycol, tetrahydrofuran, dichloromethane, chloroform, dichloroethane, chlorobenzene, dichlorobenzene, Examples include chlorobenzene, chloronaphthalene, dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, and ⁇ -butyrolactone.
  • the heteroatom compound having an unshared electron pair includes a compound represented by the following general formula (5) having a molecular weight of 10,000 or less, a heterocyclic aromatic compound, and the like.
  • R 13 to R 15 may be the same or different and are selected from hydrogen, a hydrocarbon group that may have a substituent, and a heterocyclic group that may have a substituent. R 13 to R 15 may be independent from each other or may be bonded to each other to form a ring. A 1 is selected from nitrogen and phosphorus.
  • the molecular weight here refers to the weight average molecular weight when the compound represented by the general formula (5) has a distribution in the molecular weight. Here, it is preferable that the molecular weight is 10,000 or less in order to ensure solubility in a solvent and to ensure freedom of molecular orientation.
  • hydrocarbon group which may have a substituent and the heterocyclic group which may have a substituent are common to the above description.
  • Specific examples of the compound represented by the general formula (5) include amine, butylamine, dodecylamine, dimethylamine, triethylamine, butyldimethylamine, ethylenediamine, diethylenetriamine, polyethyleneimine, pyrrolidine, piperidine, and 1,4-diazabicyclo.
  • Amine compounds such as octane, aniline, 1-naphthylamine, 1-aminoanthracene, 2-aminophenol, 1,4-phenylenediamine, phosphine, tributylphosphine, triphenylphosphine, 1,2- Phosphine compounds such as bis (dimethylphosphino) ethane and 1,2-bis (diphenylphosphino) ethane.
  • the exemplified compounds are a part included in the present invention and are not particularly limited thereto.
  • heterocyclic aromatic compounds examples include azirine compounds, azeto compounds, pyrrole compounds, imidazole compounds, pyrazole compounds, triazole compounds, oxazole compounds, thiazole compounds, thiophene compounds, furan compounds, phosphole compounds, pyridine compounds, and pyrimidines.
  • examples thereof include a compound, a pyridazine compound, a pyrazine compound, a phosphinine compound, and an azepine compound.
  • a phenanthroline compound examples include bathocuproin, neocuproin, and compounds disclosed in JP-A No. 2004-281390.
  • the exemplified compounds are a part included in the present invention and are not particularly limited thereto.
  • Examples of the protonic acid include carboxylic acids such as formic acid, acetic acid, trifluoroacetic acid, heptadecanofluorononanoic acid, butyric acid, oxalic acid, and benzoic acid, sulfonic acids such as methanesulfonic acid, benzenesulfonic acid, and tosylic acid, Examples include hydrofluoric acid, hydrochloric hydrobromic acid, hydroiodic acid, sulfuric acid, nitric acid, perchloric acid, phosphoric acid, boric acid, inorganic acids such as chromic acid, and phenol.
  • carboxylic acids such as formic acid, acetic acid, trifluoroacetic acid, heptadecanofluorononanoic acid, butyric acid, oxalic acid, and benzoic acid
  • sulfonic acids such as methanesulfonic acid, benzenesulfonic acid, and tosylic acid
  • a film may be formed using the same coating method as that for producing the photoelectric conversion layer, and the formation method is selected depending on the electron extraction layer to be obtained, such as film thickness control and orientation control. That's fine.
  • the compound represented by the general formulas (1) to (3) of the present invention preferably has a concentration of 0.01 to 5 g / L.
  • An electron extraction layer with a thickness of about 0.1 to 40 nm can be obtained.
  • the formed electron extraction layer may be subjected to an annealing treatment under reduced pressure or in an inert atmosphere (nitrogen or argon atmosphere).
  • a preferable temperature for the annealing treatment is 40 ° C to 300 ° C, more preferably 50 ° C to 200 ° C. This annealing treatment may be performed after the formation of the cathode.
  • a metal electrode such as Ag is formed on the electron extraction layer by vacuum deposition or sputtering.
  • the metal electrode is preferably formed continuously while maintaining the vacuum.
  • a desired p-type organic semiconductor material such as PEDOT
  • spin coating bar coating, blade casting, or the like
  • solvent is removed using a vacuum thermostat or a hot plate to form a hole extraction layer.
  • an inorganic material such as molybdenum oxide
  • a vacuum deposition method using a vacuum deposition machine can be applied.
  • the photovoltaic element of the present invention can be applied to various photoelectric conversion devices using a photoelectric conversion function, an optical rectification function, and the like.
  • photovoltaic cells such as solar cells
  • electronic devices such as optical sensors, optical switches, phototransistors
  • optical recording materials such as optical memories
  • A-2 Compound represented by the following formula
  • PCBM phenyl C71 butyric acid methyl ester
  • CF chloroform
  • IPA 2-propanol
  • BCP 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (bathocuproine)
  • PFN Compound represented by the following formula
  • the compound A-1 was manufactured by 1-Material.
  • Compound A-2 was synthesized according to the method described in Applied Physics Letters 2009, Vol. 95, 053701.
  • the compound PFN was synthesized by the method described in Chemistry of Materials, 2004, Vol. 16, pages 708-716.
  • the deterioration rate of the photoelectric conversion efficiency in each example / comparative example was obtained by the following equation.
  • Deterioration rate (%) photoelectric conversion efficiency after continuous light irradiation (%) / photoelectric conversion efficiency immediately after the start of light irradiation (%) ⁇ 100
  • Example 1 0.10 mL of CF solvent is added to a sample bottle containing 0.4 mg of A-1 and 0.6 mg of [70] PCBM (Soleine), and an ultrasonic cleaning machine (US-manufactured by Iuchi Seieido Co., Ltd.). 2, solution A was obtained by ultrasonic irradiation for 30 minutes in an output of 120 W).
  • a glass substrate on which an ITO transparent conductive layer serving as an anode was deposited to 125 nm by sputtering was cut into 38 mm ⁇ 46 mm, and then ITO was patterned into a 38 mm ⁇ 13 mm rectangular shape by photolithography.
  • the light transmittance of the obtained substrate was measured with a Hitachi spectrophotometer U-3010. As a result, it was 85% or more in all wavelength regions from 400 nm to 900 nm.
  • the substrate was subjected to ultrasonic cleaning with an alkali cleaning solution (“Semico Clean” EL56, manufactured by Furuuchi Chemical Co., Ltd.) for 10 minutes, and then cleaned with ultrapure water.
  • PEDOT: PSS aqueous solution (0.8% by weight of PEDOT, 0.5% by weight of PSS) was applied on the substrate by spin coating, and dried by heating at 200 ° C. for 5 minutes on a hot plate. The film was formed to a thickness of 60 nm.
  • the above solution A was dropped on the PEDOT: PSS layer, and a photoelectric conversion layer having a thickness of 100 nm was formed by spin coating.
  • a 0.2 g / L IPA solution of hexyltrimethylammonium bromide (manufactured by Tokyo Chemical Industry Co., Ltd.) was dropped on the photoelectric conversion layer, and a film was formed by spin coating.
  • the substrate and the cathode mask are placed in a vacuum vapor deposition apparatus, and the degree of vacuum in the apparatus is evacuated to 1 ⁇ 10 ⁇ 3 Pa or less, and the aluminum layer serving as the cathode is formed to a thickness of 100 nm by resistance heating. Vapor deposited.
  • the extraction electrodes were taken out from the upper and lower electrodes of the manufactured element, and a photovoltaic element having an area where the band-like ITO layer and the silver layer overlap each other was 5 mm ⁇ 5 mm was manufactured.
  • the upper and lower electrodes of the photovoltaic device thus produced were connected to a picoammeter / voltage source 4140B manufactured by Hewlett-Packard Co., and white light (AM1.5; 100 mW / cm from the ITO layer side in the atmosphere). 2 ), and the current value was measured when the applied voltage was changed from -1V to + 2V. The measurement was performed immediately after the start of light irradiation. As a result of calculating photoelectric conversion efficiency ( ⁇ ) from the obtained current value, it was 5.02%.
  • Example 2 A photovoltaic device was produced in the same manner as in Example 1 except that octyltrimethylammonium bromide (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of hexyltrimethylammonium bromide, and the photoelectric conversion efficiency ( ⁇ ) was calculated. The result was 4.98%.
  • Example 3 A photovoltaic device was produced in the same manner as in Example 1 except that dodecyltrimethylammonium bromide (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of hexyltrimethylammonium bromide, and the photoelectric conversion efficiency ( ⁇ ) was calculated. The result was 4.86%.
  • dodecyltrimethylammonium bromide manufactured by Tokyo Chemical Industry Co., Ltd.
  • ⁇ photoelectric conversion efficiency
  • Example 4 A photovoltaic device was produced in the same manner as in Example 1 except that tetrabutylammonium bromide (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of hexyltrimethylammonium bromide, and the photoelectric conversion efficiency ( ⁇ ) was calculated. The result was 4.99%.
  • Example 5 A photovoltaic device was produced in the same manner as in Example 1 except that octadecyltrimethylammonium bromide (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of hexyltrimethylammonium bromide, and the photoelectric conversion efficiency ( ⁇ ) was calculated. The result was 5.35%.
  • Example 6 Other than using 0.2 g / L IPA solution of octadecyltrimethylammonium bromide (manufactured by Tokyo Chemical Industry Co., Ltd.) instead of 0.2 g / L IPA solution of hexyltrimethylammonium bromide (manufactured by Tokyo Chemical Industry Co., Ltd.) Produced a photovoltaic device exactly as in Example 1, and the photoelectric conversion efficiency ( ⁇ ) was calculated to be 4.80%.
  • Example 7 Instead of 0.2 g / L IPA solution of hexyltrimethylammonium bromide (Tokyo Chemical Industry Co., Ltd.), 0.2 g / L IPA (acetic acid) of polyethyleneimine (average molecular weight 10,000) (manufactured by Waken Pharmaceutical Co., Ltd.) A photovoltaic device was prepared in the same manner as in Example 1 except that the 0.5% addition solution was used, and the photoelectric conversion efficiency ( ⁇ ) was calculated to be 4.43%.
  • ⁇ photoelectric conversion efficiency
  • Example 8 A photovoltaic device was prepared in the same manner as in Example 1 except that hexadecylpyridinium bromide hydrate (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of hexyltrimethylammonium bromide, and photoelectric conversion efficiency ( ⁇ ) As a result, it was 4.66%.
  • Example 9 A photovoltaic device was produced in the same manner as in Example 1 except that hexadecyldimethyl (3-sulfopropyl) ammonium hydroxide inner salt (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of hexyltrimethylammonium bromide.
  • the photoelectric conversion efficiency ( ⁇ ) was calculated to be 4.74%.
  • Example 10 A photovoltaic device was produced in the same manner as in Example 1 except that tetrabutylammonium chloride (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of hexyltrimethylammonium bromide, and the photoelectric conversion efficiency ( ⁇ ) was calculated. The result was 4.93%.
  • Example 11 A photovoltaic device was prepared in the same manner as in Example 1 except that tributylhexadecylphosphonium bromide (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of hexyltrimethylammonium bromide, and the photoelectric conversion efficiency ( ⁇ ) was calculated. As a result, it was 5.00%.
  • tributylhexadecylphosphonium bromide manufactured by Tokyo Chemical Industry Co., Ltd.
  • Example 12 A photovoltaic device was produced in the same manner as in Example 1 except that 1-butyl-1-methylpiperidinium bromide (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of hexyltrimethylammonium bromide, and photoelectric conversion was performed. As a result of calculating the efficiency ( ⁇ ), it was 4.76%.
  • Example 13 A photovoltaic device was prepared in the same manner as in Example 1 except that 1-butyl-3-methylimidazolium bromide (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of hexyltrimethylammonium bromide, and the photoelectric conversion efficiency As a result of calculating ( ⁇ ), it was 4.68%.
  • 1-butyl-3-methylimidazolium bromide manufactured by Tokyo Chemical Industry Co., Ltd.
  • Example 14 Solution A was prepared using A-2 instead of A-1, 0.2 mg of A-2 and 0.8 mg of [70] PCBM, and tetrabutylammonium bromide (Tokyo) instead of hexyltrimethylammonium bromide
  • a photovoltaic device was produced in the same manner as in Example 1 except that Kasei Kogyo Co., Ltd. was used, and the photoelectric conversion efficiency ( ⁇ ) was calculated to be 4.85%.
  • Example 15 A-2 was used instead of A-1, 0.2 mg of A-2 and 0.8 mg of [70] PCBM were used to prepare solution A, and hexyltrimethylammonium bromide was replaced by the following formula
  • a photovoltaic device was produced in the same manner as in Example 1 except that a 0.5 + 0.5 g / L methanol solution of the compound (B-1) and heptadecafluorononanoic acid was used, and the photoelectric conversion efficiency ( ⁇ ) was As a result of calculation, it was 4.85%.
  • Example 16 A-2 was used instead of A-1, 0.2 mg of A-2 and 0.8 mg of [70] PCBM were used to prepare solution A, and hexyltrimethylammonium bromide was replaced by the following formula
  • a photovoltaic device was produced in the same manner as in Example 1 except that a 0.5 + 0.5 g / L methanol solution of the compound (B-2) and heptadecafluorononanoic acid was used, and the photoelectric conversion efficiency ( ⁇ ) was As a result of calculation, it was 4.69%.
  • Example 17 A-2 was used instead of A-1, 0.2 mg of A-2 and 0.8 mg of [70] PCBM were used to prepare solution A, and hexyltrimethylammonium bromide was replaced by the following formula
  • a photovoltaic device was produced in the same manner as in Example 1 except that a 0.5 + 0.5 g / L methanol solution of compound (B-3) and heptadecafluorononanoic acid was used, and the photoelectric conversion efficiency ( ⁇ ) was As a result of calculation, it was 4.78%.
  • Example 18 was used instead of A-1, 0.2 mg of A-2 and 0.8 mg of [70] PCBM were used to prepare solution A, and hexyltrimethylammonium bromide was replaced by the following formula
  • a photovoltaic device was produced in the same manner as in Example 1 except that a 0.5 + 0.5 g / L methanol solution of compound (B-4) and heptadecafluorononanoic acid was used, and the photoelectric conversion efficiency ( ⁇ ) was As a result of calculation, it was 4.72%.
  • Example 19 A-2 was used instead of A-1, 0.2 mg of A-2 and 0.8 mg of [70] PCBM were used to prepare solution A, and hexyltrimethylammonium bromide was replaced by the following formula
  • a photovoltaic device was prepared in the same manner as in Example 1 except that a 0.5 + 0.5 g / L methanol solution of the compound (B-5) and heptadecafluorononanoic acid was used, and the photoelectric conversion efficiency ( ⁇ ) was As a result of calculation, it was 4.88%.
  • Example 20 Solution A was prepared using A-2 instead of A-1, 0.2 mg A-2 and 0.8 mg [70] PCBM, and BCP and heptadecafluorononane replaced with hexyltrimethylammonium bromide
  • a photovoltaic device was prepared in the same manner as in Example 1 except that a 0.5 + 0.5 g / L methanol solution of acid was used, and the photoelectric conversion efficiency ( ⁇ ) was calculated to be 4.77%. .
  • Comparative Example 1 A photovoltaic device was produced in the same manner as in Example 1 except that the electron extraction layer was not provided, and the photoelectric conversion efficiency ( ⁇ ) was calculated. As a result, it was 3.59%.
  • Comparative Example 2 Other than using 0.2 g / L IPA solution of hexyltrimethylammonium bromide (manufactured by Tokyo Chemical Industry Co., Ltd.), 0.5 g / L methanol solution of polyethylene oxide (average molecular weight 100,000) (manufactured by Sigma-Aldrich) was used. Produced a photovoltaic device in exactly the same manner as in Example 1, and the photoelectric conversion efficiency ( ⁇ ) was calculated to be 3.63%.
  • Comparative Example 3 Instead of the 0.2 g / L IPA solution of hexyltrimethylammonium bromide (manufactured by Tokyo Chemical Industry Co., Ltd.), a 1.0 g / L methanol (1% acetic acid added) solution of PFN (average molecular weight 14000) was used. A photovoltaic device was produced in exactly the same manner as in Example 1, and the photoelectric conversion efficiency ( ⁇ ) was calculated. As a result, it was 0.02%.
  • Comparative Example 4 A-2 was used instead of A-1, solution A was prepared using 0.2 mg of A-2 and 0.8 mg of [70] PCBM, and except that no electron extraction layer was provided. A photovoltaic device was produced in exactly the same manner, and the photoelectric conversion efficiency ( ⁇ ) was calculated to be 4.46%.

Abstract

The present invention provides a photovoltaic element which has high photoelectric conversion efficiency. This photovoltaic element comprises at least a positive electrode, a photoelectric conversion layer, an electron extraction layer and a negative electrode in this order, and is characterized in that the electron extraction layer contains at least one compound that is selected from a group of compounds represented by a specific general formula and having a molecular weight of 10,000 or less.

Description

光起電力素子Photovoltaic element
　本発明は光起電力素子に関する。 The present invention relates to a photovoltaic device.
　太陽電池は環境に優しい電気エネルギー源として、現在深刻さを増すエネルギー問題に対して有力なエネルギー源と注目されている。現在、太陽電池の光起電力素子の半導体材料としては、単結晶シリコン、多結晶シリコン、アモルファスシリコン、化合物半導体などの無機物が使用されている。しかし、無機半導体を用いて製造される太陽電池は、火力発電や原子力発電などの発電方式と比べてコストが高いために、一般家庭に広く普及するには至っていない。コスト高の要因は主として、真空かつ高温下で半導体薄膜を形成するプロセスにある。そこで、製造プロセスの簡略化が期待される半導体材料として、共役系重合体や有機結晶などの有機半導体や有機色素を用いた有機太陽電池が検討されている。このような有機太陽電池においては、半導体材料を塗布法で作製することが可能なため、製造プロセスを簡略化することができる。 Solar cells are attracting attention as an environmentally friendly electrical energy source and an influential energy source for increasing energy problems. At present, inorganic materials such as single crystal silicon, polycrystalline silicon, amorphous silicon, and compound semiconductors are used as semiconductor materials for photovoltaic elements of solar cells. However, solar cells manufactured using inorganic semiconductors have not been widely used in ordinary households because of high costs compared with power generation methods such as thermal power generation and nuclear power generation. The high cost factor is mainly in the process of forming the semiconductor thin film under vacuum and high temperature. Therefore, organic semiconductor cells using organic semiconductors such as conjugated polymers and organic crystals and organic dyes are being studied as semiconductor materials that are expected to simplify the manufacturing process. In such an organic solar cell, a semiconductor material can be manufactured by a coating method, so that the manufacturing process can be simplified.
　しかし、共役系重合体などを用いた従来の有機太陽電池は、従来の無機半導体を用いた太陽電池と比べて光電変換効率が低いために、まだ実用化には至っていない。有機太陽電池の実用化のためには、より高い光電変換効率を実現しうる手法の開拓が必須である。 However, a conventional organic solar cell using a conjugated polymer or the like has not yet been put into practical use because it has a lower photoelectric conversion efficiency than a conventional solar cell using an inorganic semiconductor. In order to put organic solar cells into practical use, it is essential to develop methods that can achieve higher photoelectric conversion efficiency.
　有機太陽電池の光電変換効率を向上させる方法としては、例えば、銅フタロシアニンとフラーレンの積層膜から成る光電変換層と銀陰極との間に、電子取り出し層を設ける方法があげられる。この方法によって、銀陰極蒸着による光電変換層の劣化が抑制される等により、変換効率が向上する。　そして、有機太陽電池の電子取り出し層にイオン性基を導入したポリマー材料を用いることが検討されている。例えば、アンモニウム酢酸塩が導入された置換フルオレン系ポリマー（非特許文献１）、臭化アンモニウム塩が導入された置換フルオレン系ポリマー（非特許文献２）、臭化アンモニウム塩が導入された、置換フルオレン系ポリマーと置換チオフェン系ポリマーの組み合わせ（非特許文献３）、アンモニウム酢酸塩が導入されたポリエチレンオキサイド（非特許文献４）を有機太陽電池の電子取り出し層として用いることで、変換効率が向上することが開示されている。 Examples of a method for improving the photoelectric conversion efficiency of an organic solar cell include a method of providing an electron extraction layer between a photoelectric conversion layer composed of a laminated film of copper phthalocyanine and fullerene and a silver cathode. By this method, conversion efficiency is improved, for example, by suppressing deterioration of the photoelectric conversion layer due to silver cathode deposition. And, it has been studied to use a polymer material into which an ionic group is introduced in the electron extraction layer of the organic solar cell. For example, a substituted fluorene polymer into which ammonium acetate is introduced (Non-patent Document 1), a substituted fluorene polymer into which ammonium bromide salt is introduced (Non-patent Document 2), and a substituted fluorene into which ammonium bromide salt is introduced Conversion efficiency is improved by using polyethylene oxide (Non-patent Document 4), which is a combination of a polymer based and a substituted thiophene polymer (Non-patent Document 3) and ammonium acetate, as an electron extraction layer of an organic solar cell. Is disclosed.
　しかしながら、本発明者らの知見によれば、従来のアンモニウム塩等のイオン性基を導入したポリマー材料による電子取り出し層挿入による光電変換効率の向上効果は、実用化を見据える上で未だ十分ではなかった。というのも、従来の電子取り出し層に用いられてきたアンモニウム塩等のイオン性基を導入したポリマー材料は合成が容易ではなく、コスト面での課題があった。そのことに加えて、それらのポリマー材料は高分子量体であるため分子配向の自由度に欠けるのではないかと本発明者らは考えた。すなわち、それらのポリマー材料は厚く積層すると絶縁性が増すことで素子特性低下の原因となり、それらのポリマー材料の適応膜厚は５ｎｍ以下に制限されていたのである。しかし、このように５ｎｍ以下という薄い電子取り出し層を均一に塗布することは困難であり、電子取り出し層の表面粗さが大きくなりがちであった。そして、表面粗さが大きい電子取り出し層は十分に機能せず、結局高い光電変換効率が得られないことがあった。 However, according to the knowledge of the present inventors, the effect of improving the photoelectric conversion efficiency due to the insertion of the electron extraction layer by the conventional polymer material into which an ionic group such as an ammonium salt is introduced is not yet sufficient for the practical application. It was. This is because a polymer material introduced with an ionic group such as an ammonium salt, which has been used in a conventional electron extraction layer, is not easy to synthesize and has a problem in terms of cost. In addition to that, the present inventors considered that these polymer materials are high molecular weight products and therefore lack the degree of freedom in molecular orientation. That is, when these polymer materials are laminated thickly, the insulating properties increase, which causes a decrease in device characteristics, and the adaptive film thickness of these polymer materials is limited to 5 nm or less. However, it is difficult to uniformly apply such a thin electron extraction layer of 5 nm or less, and the surface roughness of the electron extraction layer tends to increase. In addition, the electron extraction layer having a large surface roughness does not function sufficiently, and high photoelectric conversion efficiency may not be obtained after all.
　そこで、本発明は、より合成が容易であり、すなわち安価であり、且つ、電子取り出し層として適応膜厚の範囲が広い有機材料を用いた、高い光電変換効率向上効果を実現させる電子取り出し層を有する光起電力素子を提供することを目的とする。 Therefore, the present invention provides an electron extraction layer that realizes a high photoelectric conversion efficiency improvement effect by using an organic material that is easier to synthesize, that is, inexpensive, and has a wide adaptive film thickness range as the electron extraction layer. An object of the present invention is to provide a photovoltaic device having the same.
　本発明者らは、上記の課題をふまえ、上記でも述べたとおり、イオン性基が導入された化合物の分子量に着目した。そして、鋭意努力を重ね、特定のイオン性基が導入された場合において、そのイオン性基が導入された化合物を特定の分子量にすれば、分子配向の自由度を高め、より電荷が移動しやすくなることを見出すことが出来た。そして、そうした特定のイオン性基が導入された特定の分子量の化合物を電子取出し層に用いることによって、光電変換効率に優れた光起電力素子が得られることを見出すことができた。 The inventors focused on the molecular weight of a compound into which an ionic group was introduced, as described above, in view of the above problems. When a specific ionic group is introduced and a compound having the ionic group introduced is made to have a specific molecular weight, the degree of freedom in molecular orientation is increased and the charge is more easily transferred. I was able to find out. Then, it was found that a photovoltaic device having excellent photoelectric conversion efficiency can be obtained by using a compound having a specific molecular weight introduced with such a specific ionic group in the electron extraction layer.
　すなわち、本発明は、少なくとも陽極、光電変換層、電子取り出し層および陰極をこの順に有する光起電力素子であって、該電子取り出し層が、分子量が１００００以下である下記一般式（１）～（３）で表される化合物群のうち少なくとも一つを含むことを特徴とする光起電力素子である。 That is, the present invention is a photovoltaic device having at least an anode, a photoelectric conversion layer, an electron extraction layer, and a cathode in this order, and the electron extraction layer has the following general formulas (1) to (1) having a molecular weight of 10,000 or less. 3) A photovoltaic device comprising at least one compound group represented by 3).
Figure JPOXMLDOC01-appb-C000002
Figure JPOXMLDOC01-appb-C000002
（Ｒ１～Ｒ１１は、それぞれ同じでも異なっていてもよく、水素、置換基を有してもよい炭化水素基、置換基を有してもよい少なくとも酸素、窒素、リン、ケイ素およびホウ素の中から選ばれた一つの元素を含む基、および置換基を有してもよい複素環基の中から選ばれる。ただし、Ｒ５およびＲ８は水素ではない。また、Ｒ１～Ｒ１１は、お互いに独立していても、お互いに結合して環を形成していてもよい。Ａ１～Ａ３は、窒素、リンの中から選ばれる。Ｂ１ －、Ｂ２ －は、Ｆ－、Ｃｌ－、Ｂｒ－、Ｉ－、ＯＨ－、ＢＦ４ －、ＰＦ６ －、ＣｌＯ４ －、ＮＯ３ －、ＣＮ－、ＳＣＮ－、ＨＰＯ４ －、ＰＯ４ ２－、ＳＯ４ ２－、ＣＯ３ ２－、カルボン酸陰イオン、スルホン酸陰イオンの中から選ばれる。Ｘ１ －は、－ＣＯＯ－、－ＳＯ３ －、－ＰＯ４Ｈ－、－ＰＯ４ ２－、－Ｏ－ＳＯ３ －の中から選ばれる。） (R 1 to R 11 may be the same or different, and may be hydrogen, a hydrocarbon group that may have a substituent, or at least oxygen, nitrogen, phosphorus, silicon, and boron that may have a substituent. A group containing one element selected from the above and a heterocyclic group which may have a substituent, provided that R 5 and R 8 are not hydrogen, and R 1 to R 11 are A 1 to A 3 may be selected from nitrogen and phosphorus, and B 1 − and B 2 − may be F − , which may be independent from each other or bonded to each other to form a ring. , Cl − , Br − , I − , OH − , BF 4 − , PF 6 − , ClO 4 − , NO 3 − , CN − , SCN − , HPO 4 − , PO 4 2− , SO 4 2− , CO 3 2, selected from the carboxylate anion, sulfonate anion. 1 - is, -COO -, -SO 3 -, -PO 4 H -, -PO 4 2-, -O-SO 3 - chosen from among).
　本発明によれば、光電変換効率の高い光起電力素子を提供することができる。 According to the present invention, a photovoltaic device with high photoelectric conversion efficiency can be provided.
本発明の光起電力素子の一態様を示す断面図Sectional drawing which shows the one aspect | mode of the photovoltaic device of this invention
　本発明の光起電力素子は少なくとも陽極、光電変換層、電子取り出し層および陰極をこの順に有する光起電力素子であって、該電子取り出し層が、分子量が１００００以下である下記一般式（１）～（３）で表される化合物群のうち少なくとも一つを含む。 The photovoltaic element of the present invention is a photovoltaic element having at least an anode, a photoelectric conversion layer, an electron extraction layer, and a cathode in this order, and the electron extraction layer has the following general formula (1) having a molecular weight of 10,000 or less. It includes at least one of the compound groups represented by (3) to (3).
Figure JPOXMLDOC01-appb-C000003
Figure JPOXMLDOC01-appb-C000003
（Ｒ１～Ｒ１１は、それぞれ同じでも異なっていてもよく、水素、置換基を有してもよい炭化水素基、置換基を有してもよい少なくとも酸素、窒素、リン、ケイ素およびホウ素の中から選ばれた一つの元素を含む基、および置換基を有してもよい複素環基の中から選ばれる。ただし、Ｒ５およびＲ８は水素ではない。また、Ｒ１～Ｒ１１は、お互いに独立していても、お互いに結合して環を形成していてもよい。Ａ１～Ａ３は、窒素、リンの中から選ばれる。Ｂ１ －、Ｂ２ －は、Ｆ－、Ｃｌ－、Ｂｒ－、Ｉ－、ＯＨ－、ＢＦ４ －、ＰＦ６ －、ＣｌＯ４ －、ＮＯ３ －、ＣＮ－、ＳＣＮ－、ＨＰＯ４ －、ＰＯ４ ２－、ＳＯ４ ２－、ＣＯ３ ２－、カルボン酸陰イオン、スルホン酸陰イオンの中から選ばれる。Ｘ１は、－ＣＯＯ－、－ＳＯ３ －、－ＰＯ４Ｈ－、－ＰＯ４ ２－、－Ｏ－ＳＯ３ －の中から選ばれる。）
　ここでの分子量は、上記一般式（１）～（３）で表される化合物が分子量に分布を持たない場合はその分子量を、また、分布を有する場合は、その重量平均分子量のことを指す。 (R 1 to R 11 may be the same or different, and may be hydrogen, a hydrocarbon group that may have a substituent, or at least oxygen, nitrogen, phosphorus, silicon, and boron that may have a substituent. A group containing one element selected from the above and a heterocyclic group which may have a substituent, provided that R 5 and R 8 are not hydrogen, and R 1 to R 11 are A 1 to A 3 may be selected from nitrogen and phosphorus, and B 1 − and B 2 − may be F − , which may be independent from each other or bonded to each other to form a ring. , Cl − , Br − , I − , OH − , BF 4 − , PF 6 − , ClO 4 − , NO 3 − , CN − , SCN − , HPO 4 − , PO 4 2− , SO 4 2− , CO 3 2, selected from the carboxylate anion, sulfonate anion. 1, -COO -, -SO 3 -, -PO 4 H -, -PO 4 2-, -O-SO 3 - chosen from among).
The molecular weight here refers to the molecular weight when the compounds represented by the above general formulas (1) to (3) have no distribution in the molecular weight, and the weight average molecular weight when there is a distribution. .
　本発明の電子取り出し層材料の分子量は１００００以下である。それによって、溶媒への溶解性が向上するとともに、分子配向の自由度が確保されるため、電子取り出し層中を電荷が移動しやすくなり、電荷取り出し効率を向上させることができる。電子取り出し層材料の分子量は１００００以下であれば特に限定されないが、好ましくは、２０００以下であり、更に好ましくは１０００以下である。 The molecular weight of the electron extraction layer material of the present invention is 10,000 or less. Accordingly, the solubility in a solvent is improved and the degree of freedom of molecular orientation is ensured. Therefore, the charge can easily move through the electron extraction layer, and the charge extraction efficiency can be improved. Although it will not specifically limit if the molecular weight of electron extraction layer material is 10,000 or less, Preferably, it is 2000 or less, More preferably, it is 1000 or less.
　Ｒ１～Ｒ７、Ｒ９～Ｒ１１において、置換基を有してもよい炭化水素基の炭化水素基とは、アルキル基、アルキリデン基、シクロアルキル基、アルケニル基、アルキニル基、およびアリール基である。Ｒ８において、置換基を有してもよい炭化水素基の炭化水素基とは、アルキル鎖、アルキリデン鎖、シクロアルキル鎖、アルケニル鎖、アルキニル鎖、およびアリール鎖である。以下、アルキル鎖はアルキル基、アルキリデン鎖はアルキリデン基、シクロアルキル鎖はシクロアルキル基、アルケニル鎖はアルケニル基、アルキニル鎖はアルキニル基、およびアリール鎖はアリール基に含めて説明する。 In R 1 to R 7 and R 9 to R 11 , the hydrocarbon group which may have a substituent is an alkyl group, an alkylidene group, a cycloalkyl group, an alkenyl group, an alkynyl group, or an aryl group It is. In R 8 , the hydrocarbon group of the hydrocarbon group that may have a substituent is an alkyl chain, an alkylidene chain, a cycloalkyl chain, an alkenyl chain, an alkynyl chain, and an aryl chain. In the following description, an alkyl chain is an alkyl group, an alkylidene chain is an alkylidene group, a cycloalkyl chain is a cycloalkyl group, an alkenyl chain is an alkenyl group, an alkynyl chain is an alkynyl group, and an aryl chain is an aryl group.
　アルキル基とは例えばメチル基、エチル基、プロピル基、ブチル基などの飽和脂肪族炭化水素基を示す。アルキリデン基とは例えばメチリデン基などの、アルキレン基の２つの結合が同じ原子に結合する基を示す。また、シクロアルキル基とは例えばシクロプロピル基、シクロブチル基、シクロペンチル基などの環状飽和脂肪族炭化水素基を示す。また、アルケニル基とは例えばビニル基、プロペニル基、ブテニル基などの、二重結合を有する不飽和脂肪族炭化水素基を示す。また、アルキニル基とはエチニル基、プロピニル基、ブチニル基などの三重結合を有する不飽和脂肪族炭化水素基を示す。 The alkyl group represents a saturated aliphatic hydrocarbon group such as a methyl group, an ethyl group, a propyl group, or a butyl group. An alkylidene group refers to a group in which two bonds of an alkylene group are bonded to the same atom, such as a methylidene group. The cycloalkyl group represents a cyclic saturated aliphatic hydrocarbon group such as a cyclopropyl group, a cyclobutyl group, or a cyclopentyl group. Moreover, an alkenyl group shows the unsaturated aliphatic hydrocarbon group which has a double bond, such as a vinyl group, a propenyl group, and a butenyl group. Moreover, an alkynyl group shows the unsaturated aliphatic hydrocarbon group which has triple bonds, such as an ethynyl group, a propynyl group, and a butynyl group.
　また、アリール基とは例えばフェニル基、ナフチル基、ビフェニル基、フェナントリル基、アントリル基、ターフェニル基、ピレニル基、フルオレニル基、ペリレニル基、インデニル基、アズレニル基などの芳香族炭化水素基を示す。 The aryl group represents, for example, an aromatic hydrocarbon group such as phenyl, naphthyl, biphenyl, phenanthryl, anthryl, terphenyl, pyrenyl, fluorenyl, perylenyl, indenyl, and azulenyl.
　置換基を有する場合の置換基の例としては、上記アルキル基、アルキリデン基、シクロアルキル基、アルケニル基、アルキニル基、アリール基、複素環基、ハロゲン原子、水酸基、シアノ基、アジド基、ニトリル基、アルコキシ基、スルフィド基、ジスルフィド基、アミノ基、アゾ基、ホスホリル基、リン酸エステル基、スルホニル基、カルボニル基、シリル基、ボリル基、およびそれらの組み合わせから成る基などが挙げられる。 Examples of the substituent in the case of having a substituent include the alkyl group, alkylidene group, cycloalkyl group, alkenyl group, alkynyl group, aryl group, heterocyclic group, halogen atom, hydroxyl group, cyano group, azide group, and nitrile group. , Alkoxy groups, sulfide groups, disulfide groups, amino groups, azo groups, phosphoryl groups, phosphate ester groups, sulfonyl groups, carbonyl groups, silyl groups, boryl groups, and combinations thereof.
　次に、置換基を有してもよい少なくとも酸素、窒素、リン、ケイ素およびホウ素の中から選ばれた一つの元素を含む基の少なくとも酸素、窒素、ケイ素およびホウ素の中から選ばれた一つの元素を含む基とは、酸素、窒素、リン、ケイ素およびホウ素の中から選ばれた一つの元素を介して置換する置換基およびカルボニル基を示す。酸素、窒素、リン、ケイ素およびホウ素の中から選ばれた一つの元素を介して置換する置換基としては、例えば、アルコキシ基、スルフィド基、ジスルフィド基、アミノ基、アゾ基、ホスホリル基、リン酸エステル基、スルホニル基、シリル基、ボリル基などがあげられる。スルホニル基にはチオエステル基などが含まれる。また、カルボニル基にはエステル基、カルボキシル基、アシル基などが含まれる。 Next, at least one selected from oxygen, nitrogen, silicon and boron in a group containing at least one element selected from oxygen, nitrogen, phosphorus, silicon and boron which may have a substituent The group containing an element represents a substituent and a carbonyl group that are substituted via one element selected from oxygen, nitrogen, phosphorus, silicon, and boron. Examples of the substituent substituted through one element selected from oxygen, nitrogen, phosphorus, silicon, and boron include, for example, an alkoxy group, a sulfide group, a disulfide group, an amino group, an azo group, a phosphoryl group, and phosphoric acid. Examples thereof include an ester group, a sulfonyl group, a silyl group, and a boryl group. The sulfonyl group includes a thioester group and the like. The carbonyl group includes an ester group, a carboxyl group, an acyl group, and the like.
　次に、置換基を有してもよい複素環基の複素環基とは、エポキシ基、アジリジル基、エピスルフィド基、オキソラニル基、ピロリジニル基、チオラニル基、オキサニル基、ピペリジニル基、チアニル基、ピリジル基、チエニル基、フリル基、ピロリル基、オキサゾリル基、チアゾリル基、オキサジアゾリル基、チアジアゾリル基、ピラジル基、ピリミジル基、ピラゾリル基、イミダゾリル基、ベンゾチエニル基、ベンゾジチエニル基、ジベンゾフリル基、ジベンゾチエニル基、フェニルカルバゾリル基、フェノキサチエニル基、キサンテニル基、ベンゾフラニル基、チアントレニル基、インドリジニル基、フェノキサジニル基、フェノチアジニル基、アクリジニル基、フェナントロリル基、フェナントリジニル基、キノリル基、イソキノリル基、インドリル基、キノキサリニル基、シロール基、ベンゾシロール基、ジベンゾシロール基などが挙げられる。 Next, the heterocyclic group of the heterocyclic group which may have a substituent is an epoxy group, aziridyl group, episulfide group, oxolanyl group, pyrrolidinyl group, thiolanyl group, oxanyl group, piperidinyl group, thianyl group, pyridyl group , Thienyl group, furyl group, pyrrolyl group, oxazolyl group, thiazolyl group, oxadiazolyl group, thiadiazolyl group, pyrazyl group, pyrimidyl group, pyrazolyl group, imidazolyl group, benzothienyl group, benzodithienyl group, dibenzofuryl group, dibenzothienyl group , Phenylcarbazolyl group, phenoxathienyl group, xanthenyl group, benzofuranyl group, thiantenyl group, indolizinyl group, phenoxazinyl group, phenothiazinyl group, acridinyl group, phenanthrolyl group, phenanthridinyl group, quinolyl group, isoquinolyl group Group, indolyl group, a quinoxalinyl group, a silole group, Benzoshiroru group, etc. dibenzosilole group.
　置換基を有する場合の置換基の例としては、置換基を有してもよい炭化水素基の置換基の場合と同様である。 Examples of the substituent in the case of having a substituent are the same as in the case of the substituent of the hydrocarbon group which may have a substituent.
　ここで、化合物の安定性や溶媒への溶解性を向上させる観点から、前記一般式（１）～（３）においてＲ１～Ｒ４、Ｒ７、Ｒ９～Ｒ１１がアルキル基、Ｒ８がアルキル鎖であることが好ましい。このとき、同一分子内におけるＲの炭素数の合計が５以上であることがより好ましく、中でも、１６以上であることがさらに好ましい。 Here, from the viewpoint of improving the stability of the compound and the solubility in a solvent, in the general formulas (1) to (3), R 1 to R 4 , R 7 and R 9 to R 11 are alkyl groups, R 8 Is preferably an alkyl chain. At this time, the total number of carbon atoms of R in the same molecule is more preferably 5 or more, and more preferably 16 or more.
　また、Ｒ１～Ｒ１１は、お互いに独立していても、お互いに結合して環を形成していてもよいが、Ｒ５およびＲ６が互いに結合して環を形成していることが好ましい。中でも、Ｒ５およびＲ６が６員環を形成していることがより好ましい。 R 1 to R 11 may be independent from each other or may be bonded to each other to form a ring, but R 5 and R 6 may be bonded to each other to form a ring. preferable. Among these, it is more preferable that R 5 and R 6 form a 6-membered ring.
　次に、上記Ｒ１～Ｒ１１で表される具体的な置換基を例示する。ただし、例示する置換基は本発明に含まれる一部であり、特にこれに限定されるものではない。なお、以下に例示する置換基において、左水平に延びる一重線および二重線は置換基の結合位置を示す。また、末端のメチル基においては記載を省略されている場合がある。 Next, specific substituents represented by R 1 to R 11 are exemplified. However, the exemplified substituents are part of the present invention and are not particularly limited thereto. In the substituents exemplified below, a single line and a double line extending horizontally to the left indicate the bonding positions of the substituents. Moreover, description may be abbreviate | omitted in the methyl group of the terminal.
Figure JPOXMLDOC01-appb-C000004
Figure JPOXMLDOC01-appb-C000004
Figure JPOXMLDOC01-appb-C000005
Figure JPOXMLDOC01-appb-C000005
　Ａ１～Ａ３は、電荷密度が小さい軟らかい酸として存在し、安定なイオン対を形成しうる窒素またはリンから選ばれる。好ましくは、酸化反応を受けにくくより安定なイオンを形成する窒素である。 A 1 to A 3 are selected from nitrogen or phosphorus which exists as a soft acid having a small charge density and can form a stable ion pair. Nitrogen that is less susceptible to oxidation reaction and forms more stable ions is preferable.
　Ｂ１ －、Ｂ２ －は、Ｆ－、Ｃｌ－、Ｂｒ－、Ｉ－、ＯＨ－、ＢＦ４ －、ＰＦ６ －、ＣｌＯ４ －、ＮＯ３ －、ＣＮ－、ＳＣＮ－、ＨＰＯ４ －、ＰＯ４ ２－、ＳＯ４ ２－、ＣＯ３ ２－、カルボン酸陰イオン、スルホン酸陰イオンの中から選ばれる対イオンである。本発明者らの検討の結果、成膜後の安定性や光電変換層への侵食などの影響を考慮すると、好ましくはＣｌ－、Ｂｒ－であり、より好ましくは、Ｂｒ－である。 B 1 − , B 2 − represents F − , Cl − , Br − , I − , OH − , BF 4 − , PF 6 − , ClO 4 − , NO 3 − , CN − , SCN − , HPO 4 − , It is a counter ion selected from PO 4 2− , SO 4 2− , CO 3 2− , carboxylate anion, and sulfonate anion. As a result of the study by the present inventors, when considering the influence of stability after film formation and erosion to the photoelectric conversion layer, Cl − and Br − are preferable, and Br − is more preferable.
　Ｘ１ －は、－ＣＯＯ－、－ＳＯ３ －、－ＰＯ４Ｈ－、－ＰＯ４ ２－、－Ｏ－ＳＯ３ －の中から選ばれる。より高い電子取り出し効率を実現する上で、－ＳＯ３ －、－ＣＯＯ－が好ましい。 X 1 — is selected from —COO − , —SO 3 − , —PO 4 H − , —PO 4 2− , —O—SO 3 — . In order to realize higher electron extraction efficiency, —SO 3 − and —COO − are preferable.
　次に、上記一般式（１）～（３）で表される具体的な化合物を例示する。ただし、例示する化合物は本発明に含まれる一部であり、特にこれに限定されるものではない。 Next, specific compounds represented by the general formulas (1) to (3) are exemplified. However, the exemplified compounds are a part included in the present invention and are not particularly limited thereto.
　上記一般式（１）で表される化合物としては例えば、下記のような構造が挙げられる。 Examples of the compound represented by the general formula (1) include the following structures.
Figure JPOXMLDOC01-appb-C000006
Figure JPOXMLDOC01-appb-C000006
　上記一般式（２）で表される化合物としては例えば、下記のような構造が挙げられる。 Examples of the compound represented by the general formula (2) include the following structures.
Figure JPOXMLDOC01-appb-C000007
Figure JPOXMLDOC01-appb-C000007
　上記一般式（３）で表される化合物としては例えば、下記のような構造が挙げられる。 Examples of the compound represented by the general formula (3) include the following structures.
Figure JPOXMLDOC01-appb-C000008
Figure JPOXMLDOC01-appb-C000008
　上記一般式（１）～（３）で表される化合物の中では、上記一般式（１）で表される化合物が成膜性に優れ、より高い電子取り出し効率を実現させるため好ましい。 Among the compounds represented by the general formulas (1) to (3), the compound represented by the general formula (1) is preferable because it has excellent film forming properties and realizes higher electron extraction efficiency.
　次に、本発明の光起電力素子について説明する。図１は本発明の光起電力素子一態様を示す断面図である。基板１の上に陽極２、光電変換層３、上記一般式（１）～（３）で表される化合物群を含む電子取り出し層４、および陰極５をこの順に有する。 Next, the photovoltaic element of the present invention will be described. FIG. 1 is a cross-sectional view showing one embodiment of the photovoltaic device of the present invention. On a substrate 1, an anode 2, a photoelectric conversion layer 3, an electron extraction layer 4 including a compound group represented by the general formulas (1) to (3), and a cathode 5 are provided in this order.
　基板１は、電極や光電変換層が積層できるものを選択して用いることができる。例えば、無アルカリガラス、石英ガラス等の無機材料、ポリエステル、ポリカーボネート、ポリオレフィン、ポリアミド、ポリイミド、ポリフェニレンスルフィド、ポリパラキシレン、エポキシ樹脂やフッ素系樹脂等の有機材料から任意の方法によって作製されたフィルムや板が使用可能である。また、基板１側から光を入射させる場合は、基板の光透過率は６０－１００％が好ましい。ここで、光透過率とは、
［透過光強度（Ｗ／ｍ２）／入射光強度（Ｗ／ｍ２）］×１００（％）
で与えられる値である。 As the substrate 1, a substrate on which an electrode or a photoelectric conversion layer can be stacked can be selected and used. For example, films made by any method from inorganic materials such as alkali-free glass and quartz glass, organic materials such as polyester, polycarbonate, polyolefin, polyamide, polyimide, polyphenylene sulfide, polyparaxylene, epoxy resin and fluorine resin A board can be used. When light is incident from the substrate 1 side, the light transmittance of the substrate is preferably 60-100%. Here, the light transmittance is
[Transmission light intensity (W / m 2 ) / incident light intensity (W / m 2 )] × 100 (%)
The value given by.
　本発明の光起電力素子の陽極または陰極は光透過性を有する。少なくともいずれか一方が光透過性を有すればよく、両方が光透過性を有してもよい。ここで光透過性を有するとは、光電変換層に入射光が到達して起電力が発生する程度のことをいう。すなわち、光透過率として０％を超える値を有する場合、光透過性を有するという。この光透過性を有する電極は、４００ｎｍ以上９００ｎｍ以下の全ての波長領域において６０－１００％の光透過率を有することが好ましい。また、光透過性を有する電極の厚さは十分な導電性が得られればよく、材料によって異なるが、２０ｎｍ～３００ｎｍが好ましい。なお、光透過性を有さない電極は、導電性があれば十分であり、厚さも特に限定されない。 The anode or cathode of the photovoltaic element of the present invention has light transparency. It is sufficient that at least one of them has optical transparency, and both of them may have optical transparency. Here, having light transparency means that incident light reaches the photoelectric conversion layer and an electromotive force is generated. That is, when the light transmittance exceeds 0%, it is said to have light transmittance. The light-transmitting electrode preferably has a light transmittance of 60 to 100% in all wavelength regions of 400 nm to 900 nm. Further, the thickness of the light-transmitting electrode is not limited as long as sufficient conductivity is obtained and varies depending on the material, but is preferably 20 nm to 300 nm. In addition, the electrode which does not have a light transmittance should just be electroconductive, and thickness is not specifically limited, either.
　電極材料としては、陽極には仕事関数の大きな導電性材料、もう一方の陰極には仕事関数の小さな導電性材料を使用することが好ましい。 As the electrode material, it is preferable to use a conductive material having a high work function for the anode and a conductive material having a low work function for the other cathode.
　仕事関数の大きな導電性材料としては、金、白金、クロム、ニッケルなどの金属、透明性を有するインジウム、スズなどの金属酸化物や複合金属酸化物（インジウム錫酸化物（ＩＴＯ）、インジウム亜鉛酸化物（ＩＺＯ）など）、導電性高分子が好ましく用いられる。また、陽極は正孔取り出し層を有することがより好ましい。正孔取り出し層により、キャリアを取り出すのに適した界面状態を形成できる。さらに、電極間の短絡を防止する効果がある。正孔取り出し層を形成する材料としては、ドーパントを含むポリチオフェン系重合体、ポリ－ｐ－フェニレンビニレン系重合体、ポリフルオレン系重合体などの導電性高分子や、酸化モリブデンなどの金属酸化物が好ましく用いられる。なお、ポリチオフェン系重合体、ポリ－ｐ－フェニレンビニレン系重合体、ポリフルオレン系重合体とは、それぞれチオフェン骨格、ｐ－フェニレンビニレン骨格、フルオレン骨格を主鎖に有する重合体を指す。これらの中でも、酸化モリブデン、もしくはドーパントを含むポリエチレンジオキシチオフェン（ＰＥＤＯＴ）などのポリチオフェン系重合体、特にＰＥＤＯＴとポリスチレンスルホネート（ＰＳＳ）の混合物がより好ましい。また、正孔取り出し層は、これらの材料を複数積層させていてもよく、積層させる材料は異なっていてもよい。 Conductive materials with large work functions include metals such as gold, platinum, chromium and nickel, transparent metal oxides such as indium and tin, and complex metal oxides (indium tin oxide (ITO), indium zinc oxide) Products (IZO) and the like, and conductive polymers are preferably used. The anode preferably has a hole extraction layer. An interface state suitable for extracting carriers can be formed by the hole extraction layer. Furthermore, there is an effect of preventing a short circuit between the electrodes. As a material for forming the hole extraction layer, a conductive polymer such as a polythiophene polymer containing a dopant, a poly-p-phenylene vinylene polymer, a polyfluorene polymer, or a metal oxide such as molybdenum oxide may be used. Preferably used. The polythiophene polymer, the poly-p-phenylene vinylene polymer, and the polyfluorene polymer refer to polymers having a thiophene skeleton, a p-phenylene vinylene skeleton, and a fluorene skeleton in the main chain, respectively. Among these, molybdenum oxide or a polythiophene polymer such as polyethylenedioxythiophene (PEDOT) containing a dopant, particularly a mixture of PEDOT and polystyrene sulfonate (PSS) is more preferable. Moreover, the hole extraction layer may be formed by laminating a plurality of these materials, and the materials to be laminated may be different.
　仕事関数の小さな導電性材料としては、リチウムなどのアルカリ金属、マグネシウムやカルシウムなどのアルカリ土類金属、錫、銀、アルミニウムなどが好ましく用いられる。さらに、上記の金属からなる合金や上記の金属の積層体からなる電極も好ましく用いられる。また、陰極にはフッ化リチウム、フッ化セシウムなどの金属フッ化物を含んでいてもよい。 As the conductive material having a small work function, alkali metals such as lithium, alkaline earth metals such as magnesium and calcium, tin, silver, and aluminum are preferably used. Furthermore, an electrode made of an alloy made of the above metal or a laminate of the above metal is also preferably used. The cathode may contain a metal fluoride such as lithium fluoride and cesium fluoride.
　次に、本発明の光起電力素子における光電変換層について説明する。光電変換層は、前記陽極および陰極に挟持され、少なくとも後述する（Ａ）電子供与性有機半導体および（Ｂ）電子受容性有機半導体を含む。例えば、電子供与性有機半導体と電子受容性有機半導体の混合物からなる層、電子供与性有機半導体からなる層と電子受容性有機半導体からなる層を積層した構造、電子供与性有機半導体からなる層と電子受容性有機半導体からなる層の間に、これらの混合物からなる層を積層した構造などが挙げられる。電子供与性有機半導体または電子受容性有機半導体を２種以上含有してもよい。 Next, the photoelectric conversion layer in the photovoltaic device of the present invention will be described. The photoelectric conversion layer is sandwiched between the anode and the cathode and includes at least (A) an electron-donating organic semiconductor and (B) an electron-accepting organic semiconductor, which will be described later. For example, a layer composed of a mixture of an electron-donating organic semiconductor and an electron-accepting organic semiconductor, a structure in which a layer composed of an electron-donating organic semiconductor and a layer composed of an electron-accepting organic semiconductor, a layer composed of an electron-donating organic semiconductor, The structure etc. which laminated | stacked the layer which consists of these mixtures between the layers which consist of an electron-accepting organic semiconductor are mentioned. You may contain 2 or more types of electron-donating organic semiconductors or electron-accepting organic semiconductors.
　本発明における電子供与性有機半導体と電子受容性有機半導体は、混合層を形成していることが好ましい。光電変換層における電子供与性有機半導体と電子受容性有機半導体の含有比率は特に限定されないが、電子供与性有機半導体：電子受容性有機半導体の重量分率が、１～９９：９９～１の範囲であることが好ましく、より好ましくは１０～９０：９０～１０の範囲であり、さらに好ましくは２０～６０：８０～４０の範囲である。 In the present invention, the electron donating organic semiconductor and the electron accepting organic semiconductor preferably form a mixed layer. The content ratio of the electron-donating organic semiconductor and the electron-accepting organic semiconductor in the photoelectric conversion layer is not particularly limited, but the weight ratio of electron-donating organic semiconductor: electron-accepting organic semiconductor is in the range of 1 to 99:99 to 1. It is preferably in the range of 10 to 90:90 to 10, more preferably in the range of 20 to 60:80 to 40.
　光電変換層は、（Ａ）電子供与性有機半導体および（Ｂ）電子受容性有機半導体が光吸収によって光起電力を生じるのに十分な厚さがあればよい。材料によって異なるが、１０ｎｍ～１０００ｎｍの厚さが好ましく、より好ましくは５０ｎｍ～５００ｎｍである。本発明における光電変換層は、本発明の目的を阻害しない範囲において、界面活性剤やバインダー樹脂、フィラー等の他の成分を含んでいてもよい。 The photoelectric conversion layer only needs to have a thickness sufficient for (A) the electron-donating organic semiconductor and (B) the electron-accepting organic semiconductor to generate a photovoltaic force by light absorption. Although it varies depending on the material, a thickness of 10 nm to 1000 nm is preferable, and 50 nm to 500 nm is more preferable. The photoelectric conversion layer in the present invention may contain other components such as a surfactant, a binder resin, and a filler as long as the object of the present invention is not impaired.
　（Ａ）電子供与性有機半導体は、ｐ型半導体特性を示す有機物であれば特に限定されない。例えば、ポリチオフェン系重合体、２，１，３－ベンゾチアジアゾール－チオフェン系共重合体、キノキサリン－チオフェン系共重合体、チオフェンーベンゾジチオフェン系共重合体、ポリ－ｐ－フェニレンビニレン系重合体、ポリ－ｐ－フェニレン系重合体、ポリフルオレン系重合体、ポリピロール系重合体、ポリアニリン系重合体、ポリアセチレン系重合体、ポリチエニレンビニレン系重合体などの共役系重合体、Ｈ２フタロシアニン（Ｈ２Ｐｃ）、銅フタロシアニン（ＣｕＰｃ）、亜鉛フタロシアニン（ＺｎＰｃ）等のフタロシアニン誘導体、ポルフィリン誘導体、Ｎ，Ｎ’－ジフェニル－Ｎ，Ｎ’－ジ（３－メチルフェニル）－４，４’－ジフェニル－１，１’－ジアミン（ＴＰＤ）、Ｎ，Ｎ’－ジナフチル－Ｎ，Ｎ’－ジフェニル－４，４’－ジフェニル－１，１’－ジアミン（ＮＰＤ）等のトリアリールアミン誘導体、４，４’－ジ（カルバゾール－９－イル）ビフェニル（ＣＢＰ）等のカルバゾール誘導体、オリゴチオフェン誘導体（ターチオフェン、クウォーターチオフェン、セキシチオフェン、オクチチオフェンなど）等の低分子有機化合物などが挙げられる。これらを２種以上用いてもよい。 (A) An electron donating organic semiconductor will not be specifically limited if it is an organic substance which shows a p-type semiconductor characteristic. For example, polythiophene polymer, 2,1,3-benzothiadiazole-thiophene copolymer, quinoxaline-thiophene copolymer, thiophene-benzodithiophene copolymer, poly-p-phenylene vinylene polymer, Conjugated polymers such as poly-p-phenylene polymer, polyfluorene polymer, polypyrrole polymer, polyaniline polymer, polyacetylene polymer, polythienylene vinylene polymer, H 2 phthalocyanine (H 2 Pc), phthalocyanine derivatives such as copper phthalocyanine (CuPc), zinc phthalocyanine (ZnPc), porphyrin derivatives, N, N′-diphenyl-N, N′-di (3-methylphenyl) -4,4′-diphenyl-1 , 1′-diamine (TPD), N, N′-dinaphthyl-N, N′-diphenyl-4, Triarylamine derivatives such as'-diphenyl-1,1'-diamine (NPD), carbazole derivatives such as 4,4'-di (carbazol-9-yl) biphenyl (CBP), oligothiophene derivatives (terthiophene, quarter Low molecular organic compounds such as thiophene, sexithiophene, and octithiophene). Two or more of these may be used.
　ポリチオフェン系重合体とは、チオフェン骨格を主鎖に有する共役系重合体を指し、側鎖を有するものも含む。具体的には、ポリ－３－メチルチオフェン、ポリ－３－ブチルチオフェン、ポリ－３－ヘキシルチオフェン、ポリ－３－オクチルチオフェン、ポリ－３－デシルチオフェンなどのポリ－３－アルキルチオフェン、ポリ－３－メトキシチオフェン、ポリ－３－エトキシチオフェン、ポリ－３－ドデシルオキシチオフェンなどのポリ－３－アルコキシチオフェン、ポリ－３－メトキシ－４－メチルチオフェン、ポリ－３－ドデシルオキシ－４－メチルチオフェンなどのポリ－３－アルコキシ－４－アルキルチオフェンなどが挙げられる。 The polythiophene polymer refers to a conjugated polymer having a thiophene skeleton in the main chain, and includes those having a side chain. Specifically, poly-3-alkylthiophene such as poly-3-methylthiophene, poly-3-butylthiophene, poly-3-hexylthiophene, poly-3-octylthiophene, poly-3-decylthiophene, poly- Poly-3-alkoxythiophene such as 3-methoxythiophene, poly-3-ethoxythiophene, poly-3-dodecyloxythiophene, poly-3-methoxy-4-methylthiophene, poly-3-dodecyloxy-4-methylthiophene And poly-3-alkoxy-4-alkylthiophene.
　２，１，３－ベンゾチアジアゾール－チオフェン系共重合体とは、チオフェン骨格と２，１，３－ベンゾチアジアゾール骨格を主鎖に有する共役系共重合体を指す。２，１，３－ベンゾチアジアゾール－チオフェン系共重合体として、具体的には下記のような構造が挙げられる。以下の式において、ｎは１～１０００の範囲を示す。 The 2,1,3-benzothiadiazole-thiophene copolymer refers to a conjugated copolymer having a thiophene skeleton and a 2,1,3-benzothiadiazole skeleton in the main chain. Specific examples of the 2,1,3-benzothiadiazole-thiophene copolymer include the following structures. In the following formula, n represents a range of 1 to 1000.
Figure JPOXMLDOC01-appb-C000009
Figure JPOXMLDOC01-appb-C000009
　キノキサリン－チオフェン系共重合体とは、チオフェン骨格とキノキサリン骨格を主鎖に有する共役系共重合体を指す。キノキサリン－チオフェン系共重合体として、具体的には下記のような構造が挙げられる。以下の式において、ｎは１～１０００の範囲を示す。 The quinoxaline-thiophene copolymer refers to a conjugated copolymer having a thiophene skeleton and a quinoxaline skeleton in the main chain. Specific examples of the quinoxaline-thiophene copolymer include the following structures. In the following formula, n represents a range of 1 to 1000.
Figure JPOXMLDOC01-appb-C000010
Figure JPOXMLDOC01-appb-C000010
　チオフェン－ベンゾジチオフェン系重合体とは、チオフェン骨格とベンゾジチオフェン骨格を主鎖に有する共役系共重合体を指す。チオフェン－ベンゾジチオフェン系共重合体として、具体的には下記のような構造が挙げられる。以下の式において、ｎは１～１０００の範囲を示す。 The thiophene-benzodithiophene polymer refers to a conjugated copolymer having a thiophene skeleton and a benzodithiophene skeleton in the main chain. Specific examples of the thiophene-benzodithiophene copolymer include the following structures. In the following formula, n represents a range of 1 to 1000.
Figure JPOXMLDOC01-appb-C000011
Figure JPOXMLDOC01-appb-C000011
　ポリ－ｐ－フェニレンビニレン系重合体とは、ｐ－フェニレンビニレン骨格を主鎖に有する共役系重合体を指し、側鎖を有するものも含む。具体的には、ポリ［２－メトキシ－５－（２－エチルヘキシルオキシ）－１，４－フェニレンビニレン］、ポリ［２－メトキシ－５－（３’，７’－ジメチルオクチルオキシ）－１，４－フェニレンビニレン］などが挙げられる。 The poly-p-phenylene vinylene polymer refers to a conjugated polymer having a p-phenylene vinylene skeleton in the main chain, and includes those having a side chain. Specifically, poly [2-methoxy-5- (2-ethylhexyloxy) -1,4-phenylenevinylene], poly [2-methoxy-5- (3 ′, 7′-dimethyloctyloxy) -1, 4-phenylene vinylene] and the like.
　（Ｂ）電子受容性有機半導体は、ｎ型半導体特性を示す有機物であれば特に限定されない。例えば、１，４，５，８－ナフタレンテトラカルボキシリックジアンハイドライド、３，４，９，１０－ペリレンテトラカルボキシリックジアンハイドライド、Ｎ，Ｎ'－ジオクチル－３，４，９，１０－ナフチルテトラカルボキシジイミド、オキサゾール誘導体（２－（４－ビフェニリル）－５－（４－ｔ－ブチルフェニル）－１，３，４－オキサジアゾール、２，５－ジ（１－ナフチル）－１，３，４－オキサジアゾール等）、トリアゾール誘導体（３－（４－ビフェニリル）－４－フェニル－５－（４－ｔ－ブチルフェニル）－１，２，４－トリアゾール等）、フェナントロリン誘導体、フラーレン誘導体、カーボンナノチューブ、ポリ－ｐ－フェニレンビニレン系重合体にシアノ基を導入した誘導体（ＣＮ－ＰＰＶ）などが挙げられる。これらを２種以上用いてもよい。安定でキャリア移動度の高いｎ型半導体であることから、フラーレン誘導体が好ましく用いられる。 (B) The electron-accepting organic semiconductor is not particularly limited as long as it is an organic substance exhibiting n-type semiconductor characteristics. For example, 1,4,5,8-naphthalene tetracarboxylic dianhydride, 3,4,9,10-perylene tetracarboxylic dianhydride, N, N′-dioctyl-3,4,9,10-naphthyl tetracarboxy Diimide, oxazole derivative (2- (4-biphenylyl) -5- (4-tert-butylphenyl) -1,3,4-oxadiazole, 2,5-di (1-naphthyl) -1,3,4 -Oxadiazole, etc.), triazole derivatives (3- (4-biphenylyl) -4-phenyl-5- (4-t-butylphenyl) -1,2,4-triazole, etc.), phenanthroline derivatives, fullerene derivatives, carbon Nanotubes, poly-p-phenylene vinylene-based polymers, cyano group-introduced derivatives (CN-PPV), etc. . Two or more of these may be used. A fullerene derivative is preferably used because it is an n-type semiconductor that is stable and has high carrier mobility.
　上記フラーレン誘導体の具体例として、Ｃ６０、Ｃ７０、Ｃ７６、Ｃ７８、Ｃ８２、Ｃ８４、Ｃ９０、Ｃ９４を始めとする無置換のものと、［６，６］－フェニル Ｃ６１ ブチリックアシッドメチルエステル（［６，６］－Ｃ６１－ＰＣＢＭ、または［６０］ＰＣＢＭ）、［５，６］－フェニル Ｃ６１ ブチリックアシッドメチルエステル、［６，６］－フェニル Ｃ６１ ブチリックアシッドヘキシルエステル、［６，６］－フェニル Ｃ６１ ブチリックアシッドドデシルエステル、フェニル Ｃ７１ ブチリックアシッドメチルエステル（［７０］ＰＣＢＭ）を始めとする置換誘導体などが挙げられる。なかでも［７０］ＰＣＢＭがより好ましい。 Specific examples of the fullerene derivative include unsubstituted ones such as C 60 , C 70 , C 76 , C 78 , C 82 , C 84 , C 90 , C 94 , and [6,6] -phenyl C61 Rick acid methyl ester ([6,6] -C61-PCBM, or [60] PCBM), [5,6] -phenyl C61 butyric acid methyl ester, [6,6] -phenyl C61 butyric acid hexyl ester, Examples thereof include substituted derivatives such as [6,6] -phenyl C61 butyric acid dodecyl ester and phenyl C71 butyric acid methyl ester ([70] PCBM). Among these, [70] PCBM is more preferable.
　本発明の光起電力素子は、上記一般式（１）～（３）で示される化合物群を含む電子取り出し層を有する。上記電子取り出し層は従来のものより高い電子取り出し効率を実現することが可能なだけではなく、適応可能な膜厚の範囲が広いことを特徴としている。例えば分子量が１４０００である非特許文献２記載の電子取り出し層においては、約２．５ｎｍの膜厚を超えると絶縁層として機能し、光電変換効率を著しく低下させてしまうのに対し、該電子取り出し層は約２０ｎｍの膜厚でも優れた電子取り出し特性を示す。これにより表面粗さの大きな光電変換層でも表面を平滑化し、高い光電変換効率を実現することができる点で優れている。 The photovoltaic device of the present invention has an electron extraction layer containing a compound group represented by the general formulas (1) to (3). The electron extraction layer is characterized by not only being able to realize higher electron extraction efficiency than the conventional one but also having a wide range of applicable film thicknesses. For example, in the electron extraction layer described in Non-Patent Document 2 having a molecular weight of 14,000, when the film thickness exceeds about 2.5 nm, it functions as an insulating layer, and the photoelectric conversion efficiency is significantly reduced. The layer exhibits excellent electron extraction properties even at a film thickness of about 20 nm. Thereby, even a photoelectric conversion layer having a large surface roughness is excellent in that the surface can be smoothed and high photoelectric conversion efficiency can be realized.
　該電子取り出し層は本発明の効果を阻害しない範囲において、上記一般式（１）～（３）で示される化合物群以外の物質を含んでもよい。例えば、従来電荷輸送層などに用いられてきたフェナントロリン単量体化合物（バソクプロイン（ＢＣＰ））などの電子輸送性有機物である。その他、本発明の光起電力素子における光電変換層から陰極への電子の取り出しを著しく妨げない範囲において、電子輸送性を有していない物質も含んでいてもよい。 The electron extraction layer may contain substances other than the compounds represented by the general formulas (1) to (3) as long as the effects of the present invention are not impaired. For example, an electron transporting organic material such as a phenanthroline monomer compound (basocuproin (BCP)) that has been conventionally used in a charge transport layer or the like. In addition, in the photovoltaic device of the present invention, a substance that does not have an electron transporting property may be included as long as the extraction of electrons from the photoelectric conversion layer to the cathode is not significantly prevented.
　これら上記一般式（１）～（３）で示される化合物群以外の物質は、上記一般式（１）～（３）で示される化合物群との混合層を形成していてもよいし、積層構造であってもよい。混合層であった場合、該電子取り出し層における上記一般式（１）～（３）で示される化合物群の含有比率は特に限定されないが、重量比率で１～９９％の範囲であることが好ましく、より好ましくは１０～９９％の範囲である。該電子取り出し層は、所望する光起電力素子の光電変換効率に応じて適宜最適な膜厚に設定すればよいが、０．１ｎｍ～５０ｎｍの厚さが好ましく、より好ましくは０．５ｎｍ～１０ｎｍである。 These substances other than the compound groups represented by the general formulas (1) to (3) may form a mixed layer with the compound groups represented by the general formulas (1) to (3) or may be laminated. It may be a structure. In the case of a mixed layer, the content ratio of the compound groups represented by the general formulas (1) to (3) in the electron extraction layer is not particularly limited, but is preferably in the range of 1 to 99% by weight. More preferably, it is in the range of 10 to 99%. The electron extraction layer may be set to an optimum film thickness as appropriate according to the desired photoelectric conversion efficiency of the photovoltaic device, but preferably has a thickness of 0.1 nm to 50 nm, more preferably 0.5 nm to 10 nm. It is.
　また本発明の光起電力素子は、１つ以上の電荷再結合層を介して２層以上の光電変換層を積層（タンデム化）して直列接合を形成してもよい。例えば、基板／陽極／第１の光電変換層／第１の電子取り出し層／電荷再結合層／第２の光電変換層／第２の電子取り出し層／陰極という積層構成を挙げることができる。このように積層することにより、開放電圧を向上させることができる。なお、陽極と第１の光電変換層の間、および、電荷再結合層と第２の光電変換層の間に上述の正孔取り出し層を設けてもよく、第１の光電変換層と電荷再結合層の間、および、第２の光電変換層と陰極の間に上述の正孔取り出し層を設けてもよい。 In the photovoltaic device of the present invention, two or more photoelectric conversion layers may be laminated (tandemized) via one or more charge recombination layers to form a series junction. For example, a laminated structure of substrate / anode / first photoelectric conversion layer / first electron extraction layer / charge recombination layer / second photoelectric conversion layer / second electron extraction layer / cathode can be given. By laminating in this way, the open circuit voltage can be improved. Note that the hole extraction layer described above may be provided between the anode and the first photoelectric conversion layer and between the charge recombination layer and the second photoelectric conversion layer. The hole extraction layer described above may be provided between the coupling layers and between the second photoelectric conversion layer and the cathode.
　ここで用いられる電荷再結合層は、複数の光電変換層が光吸収できるようにするため、光透過性を有する必要がある。また、電荷再結合層は、十分に正孔と電子が再結合するように設計されていればよいので、必ずしも膜である必要は無く、例えば光電変換層上に一様に形成された金属クラスターであってもかまわない。従って、電荷再結合層には、上述の金、白金、クロム、ニッケル、リチウム、マグネシウム、カルシウム、錫、銀、アルミニウムなどから成る数オングストロームから数十オングストローム程度の光透過性を有する非常に薄い金属膜や金属クラスター（合金を含む）、ＩＴＯ、ＩＺＯ、ＡＺＯ、ＧＺＯ、ＦＴＯ、酸化チタンや酸化モリブデンなどの光透過性の高い金属酸化物膜およびクラスター、ＰＳＳが添加されたＰＥＤＯＴなどの導電性有機材料膜、またはこれらの複合体等が用いられる。例えば、銀を、真空蒸着法を用いて水晶振動子膜厚モニター上で数オングストローム～１ｎｍとなるように蒸着すれば、一様な銀クラスターが形成できる。その他にも、酸化チタン膜を形成するならば、アドヴァンスト　マテリアルズ（Ａｄｖａｎｃｅｄ　Ｍａｔｅｒｉａｌｓ）、２００６年、１８巻、５７２－５７６頁に記載のゾルゲル法を用いればよい。ＩＴＯ、ＩＺＯなどの複合金属酸化物であるならば、スパッタリング法を用いて製膜すればよい。これら電荷再結合層形成法や種類は、電荷再結合層形成時の光電変換層への非破壊性や、次に積層される光電変換層の形成法等を考慮して適当に選択すればよい。 The charge recombination layer used here needs to have light transmittance so that a plurality of photoelectric conversion layers can absorb light. In addition, the charge recombination layer need only be designed so that holes and electrons are sufficiently recombined. Therefore, the charge recombination layer does not necessarily have to be a film, for example, a metal cluster uniformly formed on the photoelectric conversion layer. It doesn't matter. Therefore, the charge recombination layer is a very thin metal having a light transmittance of about several angstroms to several tens of angstroms made of the above-mentioned gold, platinum, chromium, nickel, lithium, magnesium, calcium, tin, silver, aluminum, etc. Films, metal clusters (including alloys), ITO, IZO, AZO, GZO, FTO, highly transparent metal oxide films and clusters such as titanium oxide and molybdenum oxide, and conductive organic materials such as PEDOT with PSS added A material film or a composite of these is used. For example, a uniform silver cluster can be formed by depositing silver so as to have a thickness of several angstroms to 1 nm on a quartz oscillator film thickness monitor using a vacuum deposition method. In addition, if a titanium oxide film is formed, the sol-gel method described in Advanced Materials, 2006, Vol. 18, 572-576 may be used. If it is a composite metal oxide such as ITO or IZO, the film may be formed by sputtering. These charge recombination layer formation methods and types may be appropriately selected in consideration of the non-destructive property to the photoelectric conversion layer at the time of charge recombination layer formation, the formation method of the next photoelectric conversion layer, and the like. .
　次に本発明の光起電力素子の製造方法について説明する。基板上にＩＴＯなどの透明電極（この場合陽極に相当）をスパッタリング法などにより形成する。次に、電子供与性有機半導体材料、および電子受容性有機材料を含む光起電力素子用材料を溶媒に溶解させて溶液を作り、透明電極上に塗布し光電変換層を形成する。このとき用いられる溶媒は有機溶媒が好ましく、例えば、メタノール、エタノール、ブタノール、トルエン、キシレン、ｏ－クロロフェノール、アセトン、酢酸エチル、エチレングリコール、テトラヒドロフラン、ジクロロメタン、クロロホルム、ジクロロエタン、クロロベンゼン、ジクロロベンゼン、トリクロロベンゼン、クロロナフタレン、ジメチルホルムアミド、ジメチルスルホキシド、Ｎ－メチルピロリドン、γ－ブチロラクトンなどが挙げられる。これらを２種以上用いてもよい。さらに、適当な添加剤を溶媒に添加することによって、光電変換層中の電子供与性有機半導体材料、および電子受容性有機材料の相分離構造を変化させることができる。添加剤としては、例えば、１，８－オクタンジチオールなどのチオール化合物や、１，８－ジヨードオクタンなどのヨード化合物が挙げられる。 Next, a method for manufacturing the photovoltaic device of the present invention will be described. A transparent electrode such as ITO (corresponding to an anode in this case) is formed on the substrate by sputtering or the like. Next, a photovoltaic device material containing an electron-donating organic semiconductor material and an electron-accepting organic material is dissolved in a solvent to form a solution, which is applied on the transparent electrode to form a photoelectric conversion layer. The solvent used at this time is preferably an organic solvent, for example, methanol, ethanol, butanol, toluene, xylene, o-chlorophenol, acetone, ethyl acetate, ethylene glycol, tetrahydrofuran, dichloromethane, chloroform, dichloroethane, chlorobenzene, dichlorobenzene, Examples include chlorobenzene, chloronaphthalene, dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, and γ-butyrolactone. Two or more of these may be used. Furthermore, the phase separation structure of the electron-donating organic semiconductor material and the electron-accepting organic material in the photoelectric conversion layer can be changed by adding an appropriate additive to the solvent. Examples of the additive include thiol compounds such as 1,8-octanedithiol and iodo compounds such as 1,8-diiodooctane.
　本発明の電子供与性有機材料および電子受容性有機材料を混合して光電変換層を形成する場合は、本発明の電子供与性有機材料と電子受容性有機材料を所望の比率で溶媒に添加し、加熱、攪拌、超音波照射などの方法を用いて溶解させ溶液を作り、透明電極上に塗布する。また、本発明の電子供与性有機材料および電子受容性有機材料を積層して光電変換層を形成する場合は、例えば本発明電子供与性有機材料の溶液を塗布して電子供与性有機材料を有する層を形成した後に、電子受容性有機材料の溶液を塗布して層を形成する。ここで、本発明の電子供与性有機材料および電子受容性有機材料は、分子量が１０００以下程度の低分子量体である場合には、蒸着法を用いて層を形成することも可能である。 When the photoelectric conversion layer is formed by mixing the electron-donating organic material and the electron-accepting organic material of the present invention, the electron-donating organic material and the electron-accepting organic material of the present invention are added to the solvent in a desired ratio. Then, the solution is dissolved by using a method such as heating, stirring and ultrasonic irradiation, and applied onto the transparent electrode. When the photoelectric conversion layer is formed by laminating the electron donating organic material and the electron accepting organic material of the present invention, for example, a solution of the electron donating organic material of the present invention is applied to have the electron donating organic material. After forming the layer, a solution of the electron-accepting organic material is applied to form the layer. Here, when the electron-donating organic material and the electron-accepting organic material of the present invention are low molecular weight substances having a molecular weight of about 1000 or less, it is also possible to form a layer using a vapor deposition method.
　光電変換層の形成には、スピンコート塗布、ブレードコート塗布、スリットダイコート塗布、スクリーン印刷塗布、バーコーター塗布、鋳型塗布、印刷転写法、浸漬引き上げ法、インクジェット法、スプレー法、真空蒸着法など何れの方法を用いてもよく、膜厚制御や配向制御など、得ようとする光電変換層特性に応じて形成方法を選択すればよい。例えばスピンコート塗布を行う場合には、本発明の電子供与性有機材料、および電子受容性有機材料が１～２０ｇ／Ｌの濃度（本発明の電子供与性有機材料と電子受容性有機材料と溶媒を含む溶液の体積に対する、本発明の電子供与性有機材料と電子受容性有機材料の重量）であることが好ましく、この濃度にすることで厚さ５～２００ｎｍの均質な光電変換層を得ることができる。形成した光電変換層に対して、溶媒を除去するために、減圧下または不活性雰囲気下（窒素やアルゴン雰囲気下）などでアニーリング処理を行ってもよい。アニーリング処理の好ましい温度は４０℃～３００℃、より好ましくは５０℃～２００℃である。このアニーリング処理は、陰極の形成後に行ってもよい。 For the formation of the photoelectric conversion layer, any of spin coating, blade coating, slit die coating, screen printing coating, bar coater coating, mold coating, print transfer method, dip pulling method, ink jet method, spray method, vacuum deposition method, etc. This method may be used, and the formation method may be selected according to the characteristics of the photoelectric conversion layer to be obtained, such as film thickness control and orientation control. For example, when spin coating is performed, the electron donating organic material of the present invention and the electron accepting organic material have a concentration of 1 to 20 g / L (the electron donating organic material, the electron accepting organic material and the solvent of the present invention). The weight of the electron-donating organic material and the electron-accepting organic material of the present invention with respect to the volume of the solution containing is preferable, and a homogeneous photoelectric conversion layer having a thickness of 5 to 200 nm can be obtained by using this concentration. Can do. In order to remove the solvent, the formed photoelectric conversion layer may be subjected to an annealing treatment under reduced pressure or under an inert atmosphere (nitrogen or argon atmosphere). A preferable temperature for the annealing treatment is 40 ° C to 300 ° C, more preferably 50 ° C to 200 ° C. This annealing treatment may be performed after the formation of the cathode.
　次に、上記一般式（１）～（３）で示される化合物を含む電子取り出し層用材料を溶媒に溶解させて溶液を作り、光電変換層上に電子取り出し層を形成する。このとき用いられる溶媒は有機溶媒が好ましく、例えば、メタノール、エタノール、ブタノール、トルエン、キシレン、ｏ－クロロフェノール、アセトン、酢酸エチル、エチレングリコール、テトラヒドロフラン、ジクロロメタン、クロロホルム、ジクロロエタン、クロロベンゼン、ジクロロベンゼン、トリクロロベンゼン、クロロナフタレン、ジメチルホルムアミド、ジメチルスルホキシド、Ｎ－メチルピロリドン、γ－ブチロラクトンなどが挙げられる。これらを２種以上用いてもよい。また、非共有電子対を有したヘテロ原子化合物とプロトン酸を同じ溶媒中で混合することによって、上記一般式（１）、（２）で表される化合物を生成し、該電子取り出し層の形成に用いることができる。ここで非共有電子対を有したヘテロ原子化合物とは、分子量が１００００以下である下記一般式（５）で表される化合物、および複素環式芳香族化合物などが挙げられる。 Next, an electron extraction layer material containing the compounds represented by the general formulas (1) to (3) is dissolved in a solvent to form a solution, and an electron extraction layer is formed on the photoelectric conversion layer. The solvent used at this time is preferably an organic solvent, for example, methanol, ethanol, butanol, toluene, xylene, o-chlorophenol, acetone, ethyl acetate, ethylene glycol, tetrahydrofuran, dichloromethane, chloroform, dichloroethane, chlorobenzene, dichlorobenzene, Examples include chlorobenzene, chloronaphthalene, dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, and γ-butyrolactone. Two or more of these may be used. Further, by mixing a heteroatom compound having an unshared electron pair and a proton acid in the same solvent, a compound represented by the above general formulas (1) and (2) is generated, and the electron extraction layer is formed. Can be used. Here, the heteroatom compound having an unshared electron pair includes a compound represented by the following general formula (5) having a molecular weight of 10,000 or less, a heterocyclic aromatic compound, and the like.
Figure JPOXMLDOC01-appb-C000012
Figure JPOXMLDOC01-appb-C000012
　Ｒ１３～Ｒ１５は、それぞれ同じでも異なっていてもよく、水素、置換基を有してもよい炭化水素基、および置換基を有してもよい複素環基の中から選ばれる。また、Ｒ１３～Ｒ１５は、お互いに独立していても、お互いに結合して環を形成していてもよい。Ａ１は、窒素、リンの中から選ばれる。ここでの分子量は、上記一般式（５）で表される化合物が分子量に分布を有する場合、その重量平均分子量のことを指す。ここで、溶媒への溶解性を確保するとともに、分子配向の自由度を確保するために分子量が１００００以下であることが好ましい。 R 13 to R 15 may be the same or different and are selected from hydrogen, a hydrocarbon group that may have a substituent, and a heterocyclic group that may have a substituent. R 13 to R 15 may be independent from each other or may be bonded to each other to form a ring. A 1 is selected from nitrogen and phosphorus. The molecular weight here refers to the weight average molecular weight when the compound represented by the general formula (5) has a distribution in the molecular weight. Here, it is preferable that the molecular weight is 10,000 or less in order to ensure solubility in a solvent and to ensure freedom of molecular orientation.
　置換基を有してもよい炭化水素基および置換基を有してもよい複素環基は、上述した記載に共通する。 The hydrocarbon group which may have a substituent and the heterocyclic group which may have a substituent are common to the above description.
　上記一般式（５）で表される具体的な化合物としては例えば、アミン、ブチルアミン、ドデシルアミン、ジメチルアミン、トリエチルアミン、ブチルジメチルアミン、エチレンジアミン、ジエチレントリアミン、ポリエチレンイミン、ピロリジン、ピペリジン、１，４-ジアザビシクロ［２.２.２］オクタン、アニリン、１-ナフチルアミン、１-アミノアントラセン、２-アミノフェノール、１，４-フェニレンジアミンなどのアミン化合物や、ホスフィン、トリブチルホスフィン、トリフェニルホスフィン、１，２-ビス（ジメチルホスフィノ）エタン、１，２-ビス（ジフェニルホスフィノ）エタンなどのホスフィン化合物である。ただし、例示した化合物は本発明に含まれる一部であり、特にこれに限定されるものではない。 Specific examples of the compound represented by the general formula (5) include amine, butylamine, dodecylamine, dimethylamine, triethylamine, butyldimethylamine, ethylenediamine, diethylenetriamine, polyethyleneimine, pyrrolidine, piperidine, and 1,4-diazabicyclo. [2.2.2] Amine compounds such as octane, aniline, 1-naphthylamine, 1-aminoanthracene, 2-aminophenol, 1,4-phenylenediamine, phosphine, tributylphosphine, triphenylphosphine, 1,2- Phosphine compounds such as bis (dimethylphosphino) ethane and 1,2-bis (diphenylphosphino) ethane. However, the exemplified compounds are a part included in the present invention and are not particularly limited thereto.
　また、上記複素環式芳香族化合物とは、例えばアジリン化合物、アゼト化合物、ピロール化合物、イミダゾール化合物、ピラゾール化合物、トリアゾール化合物、オキサゾール化合物、チアゾール化合物、チオフェン化合物、フラン化合物、ホスホール化合物、ピリジン化合物、ピリミジン化合物、ピリダジン化合物、ピラジン化合物、ホスフィニン化合物、アゼピン化合物などが挙げられる。より高い電子輸送性を有するものとして、上記化合物の中でも、フェナントロリン化合物を用いることが好ましい。フェナントロリン化合物としては例えば、バソクプロイン、ネオクプロイン、および特開２００４－２８１３９０に開示されている化合物などが挙げられる。ただし、例示した化合物は本発明に含まれる一部であり、特にこれに限定されるものではない。 Examples of the heterocyclic aromatic compounds include azirine compounds, azeto compounds, pyrrole compounds, imidazole compounds, pyrazole compounds, triazole compounds, oxazole compounds, thiazole compounds, thiophene compounds, furan compounds, phosphole compounds, pyridine compounds, and pyrimidines. Examples thereof include a compound, a pyridazine compound, a pyrazine compound, a phosphinine compound, and an azepine compound. Among the above compounds, it is preferable to use a phenanthroline compound as a compound having higher electron transport properties. Examples of the phenanthroline compound include bathocuproin, neocuproin, and compounds disclosed in JP-A No. 2004-281390. However, the exemplified compounds are a part included in the present invention and are not particularly limited thereto.
　また、プロトン酸とは例えば、ギ酸、酢酸、トリフルオロ酢酸、ヘプタデカフルオロノナン酸、酪酸、シュウ酸、安息香酸、などのカルボン酸、メタンスルホン酸、ベンゼンスルホン酸、トシル酸などのスルホン酸、フッ酸、塩酸臭化水素酸、ヨウ化水素酸、硫酸、硝酸、過塩素酸、リン酸、ホウ酸、クロム酸などの無機酸、フェノールなどが挙げられる。 Examples of the protonic acid include carboxylic acids such as formic acid, acetic acid, trifluoroacetic acid, heptadecanofluorononanoic acid, butyric acid, oxalic acid, and benzoic acid, sulfonic acids such as methanesulfonic acid, benzenesulfonic acid, and tosylic acid, Examples include hydrofluoric acid, hydrochloric hydrobromic acid, hydroiodic acid, sulfuric acid, nitric acid, perchloric acid, phosphoric acid, boric acid, inorganic acids such as chromic acid, and phenol.
　電子取り出し層の形成には、光電変換層作製と同様の塗布法を用いて製膜してもよく、膜厚制御や配向制御など、得ようとする電子取り出し層に応じて形成方法を選択すればよい。例えばスピンコート塗布を行う場合には、本発明の上記一般式（１）～（３）で示される化合物が０．０１～５ｇ／Ｌの濃度であることが好ましく、この濃度にすることで厚さ約０．１～４０ｎｍの電子取り出し層を得ることができる。形成した電子取り出し層に対して、溶媒を除去するために、減圧下または不活性雰囲気下（窒素やアルゴン雰囲気下）などでアニーリング処理を行ってもよい。アニーリング処理の好ましい温度は４０℃～３００℃、より好ましくは５０℃～２００℃である。このアニーリング処理は、陰極の形成後に行ってもよい。 For the formation of the electron extraction layer, a film may be formed using the same coating method as that for producing the photoelectric conversion layer, and the formation method is selected depending on the electron extraction layer to be obtained, such as film thickness control and orientation control. That's fine. For example, when spin coating is performed, the compound represented by the general formulas (1) to (3) of the present invention preferably has a concentration of 0.01 to 5 g / L. An electron extraction layer with a thickness of about 0.1 to 40 nm can be obtained. In order to remove the solvent, the formed electron extraction layer may be subjected to an annealing treatment under reduced pressure or in an inert atmosphere (nitrogen or argon atmosphere). A preferable temperature for the annealing treatment is 40 ° C to 300 ° C, more preferably 50 ° C to 200 ° C. This annealing treatment may be performed after the formation of the cathode.
　電子取り出し層上にＡｇなどの金属電極（この場合陰極に相当）を真空蒸着法やスパッタ法により形成する。金属電極は、電子取り出し層を真空蒸着した場合は、引き続き、真空を保持したまま続けて形成することが好ましい。 A metal electrode such as Ag (in this case, corresponding to the cathode) is formed on the electron extraction layer by vacuum deposition or sputtering. When the electron extraction layer is vacuum-deposited, the metal electrode is preferably formed continuously while maintaining the vacuum.
　陽極と光電変換層の間に正孔取り出し層を設ける場合には、所望のｐ型有機半導体材料（ＰＥＤＯＴなど）を陽極上にスピンコート法、バーコーティング法、ブレードによるキャスト法等で塗布した後、真空恒温槽やホットプレートなどを用いて溶媒を除去し、正孔取り出し層を形成する。酸化モリブデンなどの無機材料を使用する場合には、真空蒸着機を用いた真空蒸着法を適用することも可能である。 When a hole extraction layer is provided between the anode and the photoelectric conversion layer, a desired p-type organic semiconductor material (such as PEDOT) is applied on the anode by spin coating, bar coating, blade casting, or the like. Then, the solvent is removed using a vacuum thermostat or a hot plate to form a hole extraction layer. When an inorganic material such as molybdenum oxide is used, a vacuum deposition method using a vacuum deposition machine can be applied.
　本発明の光起電力素子は、光電変換機能、光整流機能などを利用した種々の光電変換デバイスへの応用が可能である。例えば光電池（太陽電池など）、電子素子（光センサ、光スイッチ、フォトトランジスタなど）、光記録材（光メモリなど）などに有用である。 The photovoltaic element of the present invention can be applied to various photoelectric conversion devices using a photoelectric conversion function, an optical rectification function, and the like. For example, it is useful for photovoltaic cells (such as solar cells), electronic devices (such as optical sensors, optical switches, phototransistors), optical recording materials (such as optical memories), and the like.
　以下、本発明を実施例に基づいてさらに具体的に説明する。なお、本発明は下記実施例に限定されるものではない。また実施例等で用いた化合物のうち、略語を使用しているものについて、以下に示す。
Ｉｓｃ：短絡電流密度
Ｖｏｃ：開放電圧
η：光電変換効率
ＩＴＯ：インジウム錫酸化物
ＰＥＤＯＴ：ポリエチレンジオキシチオフェン
ＰＳＳ：ポリスチレンスルホネート
Ａ－１：下記式で表される化合物 Hereinafter, the present invention will be described more specifically based on examples. In addition, this invention is not limited to the following Example. Of the compounds used in the examples and the like, those using abbreviations are shown below.
Isc: short-circuit current density Voc: open circuit voltage η: photoelectric conversion efficiency ITO: indium tin oxide PEDOT: polyethylene dioxythiophene PSS: polystyrene sulfonate A-1: compound represented by the following formula
Figure JPOXMLDOC01-appb-C000013
Figure JPOXMLDOC01-appb-C000013
Ａ－２：下記式で表される化合物 A-2: Compound represented by the following formula
Figure JPOXMLDOC01-appb-C000014
Figure JPOXMLDOC01-appb-C000014
［７０］ＰＣＢＭ：フェニル Ｃ７１ ブチリックアシッドメチルエステル
ＣＦ：クロロホルム
ＩＰＡ：２－プロパノール
ＢＣＰ：２，９－ジメチル－４，７－ジフェニル－１，１０－フェナントロリン（バソクプロイン）
ＰＦＮ：下記式で表される化合物 [70] PCBM: phenyl C71 butyric acid methyl ester CF: chloroform IPA: 2-propanol BCP: 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (bathocuproine)
PFN: Compound represented by the following formula
Figure JPOXMLDOC01-appb-C000015
Figure JPOXMLDOC01-appb-C000015
　なお上記化合物Ａ－１は１－マテリアル社製を用いた。上記化合物Ａ－２はアプライドフィジックス　レター（Ａｐｐｌｉｅｄ　Ｐｈｙｓｉｃｓ　Ｌｅｔｔｅｒｓ）２００９年、９５巻、０５３７０１に記載の方法によって合成した。上記化合物ＰＦＮはケミストリー　オブ　マテリアルズ（Ｃｈｅｍｉｓｔｒｙ　ｏｆ　Ｍａｔｅｒｉａｌｓ）、２００４年、１６巻、７０８－７１６頁に記載の方法によって合成した。 The compound A-1 was manufactured by 1-Material. Compound A-2 was synthesized according to the method described in Applied Physics Letters 2009, Vol. 95, 053701. The compound PFN was synthesized by the method described in Chemistry of Materials, 2004, Vol. 16, pages 708-716.
　各実施例・比較例における光電変換効率は、次式により求めた。
η（％）＝Ｉｓｃ（ｍＡ／ｃｍ２）×Ｖｏｃ（Ｖ）×ＦＦ／照射光強度（ｍＷ／ｃｍ２）×１００
ＦＦ＝ＪＶｍａｘ／（Ｉｓｃ（ｍＡ／ｃｍ２）×Ｖｏｃ（Ｖ））
ＪＶｍａｘ（ｍＷ／ｃｍ２）は、印加電圧が０Ｖから開放電圧までの間で電流密度と印加電圧の積が最大となる点における電流密度と印加電圧の積の値である。 The photoelectric conversion efficiency in each example / comparative example was determined by the following equation.
η (%) = Isc (mA / cm 2 ) × Voc (V) × FF / irradiation light intensity (mW / cm 2 ) × 100
FF = JVmax / (Isc (mA / cm 2 ) × Voc (V))
JVmax (mW / cm 2 ) is a value of the product of the current density and the applied voltage at the point where the product of the current density and the applied voltage is maximum between the applied voltage of 0 V and the open circuit voltage.
　各実施例・比較例における光電変換効率の劣化率は、次式により求めた。
劣化率（％）＝連続光照射後の光電変換効率（％）／光照射開始直後の光電変換効率（％）×１００
　実施例１
　ＣＦ溶媒０．１０ｍＬを、Ａ－１　０．４ｍｇ、［７０］ＰＣＢＭ（ソレーヌ社製）０．６ｍｇの入ったサンプル瓶の中に加え、超音波洗浄機（井内盛栄堂（株）製ＵＳ－２、出力１２０Ｗ）中で３０分間超音波照射することにより溶液Ａを得た。 The deterioration rate of the photoelectric conversion efficiency in each example / comparative example was obtained by the following equation.
Deterioration rate (%) = photoelectric conversion efficiency after continuous light irradiation (%) / photoelectric conversion efficiency immediately after the start of light irradiation (%) × 100
Example 1
0.10 mL of CF solvent is added to a sample bottle containing 0.4 mg of A-1 and 0.6 mg of [70] PCBM (Soleine), and an ultrasonic cleaning machine (US-manufactured by Iuchi Seieido Co., Ltd.). 2, solution A was obtained by ultrasonic irradiation for 30 minutes in an output of 120 W).
　スパッタリング法により陽極となるＩＴＯ透明導電層を１２５ｎｍ堆積させたガラス基板を３８ｍｍ×４６ｍｍに切断した後、ＩＴＯをフォトリソグラフィー法により３８ｍｍ×１３ｍｍの長方形状にパターニングした。得られた基板の光透過率を日立分光光度計Ｕ－３０１０で測定した結果、４００ｎｍ～９００ｎｍの全ての波長領域において８５％以上であった。この基板をアルカリ洗浄液（フルウチ化学（株）製、“セミコクリーン”ＥＬ５６）で１０分間超音波洗浄した後、超純水で洗浄した。この基板を３０分間ＵＶ／オゾン処理した後に、基板上にＰＥＤＯＴ：ＰＳＳ水溶液（ＰＥＤＯＴ０．８重量％、ＰＳＳ０．５重量％）をスピンコート法により塗布し、ホットプレートにより２００℃で５分間加熱乾燥して６０ｎｍの厚さに成膜した。上記の溶液ＡをＰＥＤＯＴ：ＰＳＳ層上に滴下し、スピンコート法により膜厚１００ｎｍの光電変換層を形成した。その後、ヘキシルトリメチルアンモニウムブロミド（東京化成工業（株）製）の０．２ｇ／Ｌ　ＩＰＡ溶液を光電変換層上に滴下し、スピンコート法により成膜した。その後、基板と陰極用マスクを真空蒸着装置内に設置して、装置内の真空度を１×１０－３Ｐａ以下になるまで排気し、抵抗加熱法によって、陰極となるアルミニウム層を１００ｎｍの厚さに蒸着した。作製した素子の上下の電極から引き出し電極を取り出し、帯状のＩＴＯ層と銀層が重なり合う部分の面積が５ｍｍ×５ｍｍである光起電力素子を作製した。 A glass substrate on which an ITO transparent conductive layer serving as an anode was deposited to 125 nm by sputtering was cut into 38 mm × 46 mm, and then ITO was patterned into a 38 mm × 13 mm rectangular shape by photolithography. The light transmittance of the obtained substrate was measured with a Hitachi spectrophotometer U-3010. As a result, it was 85% or more in all wavelength regions from 400 nm to 900 nm. The substrate was subjected to ultrasonic cleaning with an alkali cleaning solution (“Semico Clean” EL56, manufactured by Furuuchi Chemical Co., Ltd.) for 10 minutes, and then cleaned with ultrapure water. After this substrate was UV / ozone treated for 30 minutes, PEDOT: PSS aqueous solution (0.8% by weight of PEDOT, 0.5% by weight of PSS) was applied on the substrate by spin coating, and dried by heating at 200 ° C. for 5 minutes on a hot plate. The film was formed to a thickness of 60 nm. The above solution A was dropped on the PEDOT: PSS layer, and a photoelectric conversion layer having a thickness of 100 nm was formed by spin coating. Thereafter, a 0.2 g / L IPA solution of hexyltrimethylammonium bromide (manufactured by Tokyo Chemical Industry Co., Ltd.) was dropped on the photoelectric conversion layer, and a film was formed by spin coating. Thereafter, the substrate and the cathode mask are placed in a vacuum vapor deposition apparatus, and the degree of vacuum in the apparatus is evacuated to 1 × 10 −3 Pa or less, and the aluminum layer serving as the cathode is formed to a thickness of 100 nm by resistance heating. Vapor deposited. The extraction electrodes were taken out from the upper and lower electrodes of the manufactured element, and a photovoltaic element having an area where the band-like ITO layer and the silver layer overlap each other was 5 mm × 5 mm was manufactured.
　このようにして作製された光起電力素子の上下の電極をヒューレット・パッカード社製ピコアンメーター／ボルテージソース４１４０Ｂに接続して、大気下でＩＴＯ層側から白色光（ＡＭ１．５；１００ｍＷ／ｃｍ２）を照射し、印加電圧を－１Ｖから＋２Ｖまで変化させたときの電流値を測定した。測定は光照射開始直後に行った。得られた電流値より光電変換効率（η）を算出した結果、５．０２％であった。 The upper and lower electrodes of the photovoltaic device thus produced were connected to a picoammeter / voltage source 4140B manufactured by Hewlett-Packard Co., and white light (AM1.5; 100 mW / cm from the ITO layer side in the atmosphere). 2 ), and the current value was measured when the applied voltage was changed from -1V to + 2V. The measurement was performed immediately after the start of light irradiation. As a result of calculating photoelectric conversion efficiency (η) from the obtained current value, it was 5.02%.
　実施例２
　ヘキシルトリメチルアンモニウムブロミドに替えてオクチルトリメチルアンモニウムブロミド（東京化成工業（株）製）を用いた他は実施例１と全く同様にして光起電力素子を作製し、光電変換効率（η）を算出した結果、４．９８％であった。 Example 2
A photovoltaic device was produced in the same manner as in Example 1 except that octyltrimethylammonium bromide (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of hexyltrimethylammonium bromide, and the photoelectric conversion efficiency (η) was calculated. The result was 4.98%.
　実施例３
　ヘキシルトリメチルアンモニウムブロミドに替えてドデシルトリメチルアンモニウムブロミド（東京化成工業（株）製）を用いた他は実施例１と全く同様にして光起電力素子を作製し、光電変換効率（η）を算出した結果、４．８６％であった。 Example 3
A photovoltaic device was produced in the same manner as in Example 1 except that dodecyltrimethylammonium bromide (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of hexyltrimethylammonium bromide, and the photoelectric conversion efficiency (η) was calculated. The result was 4.86%.
　実施例４
　ヘキシルトリメチルアンモニウムブロミドに替えてテトラブチルアンモニウムブロミド（東京化成工業（株）製）を用いた他は実施例１と全く同様にして光起電力素子を作製し、光電変換効率（η）を算出した結果、４．９９％であった。 Example 4
A photovoltaic device was produced in the same manner as in Example 1 except that tetrabutylammonium bromide (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of hexyltrimethylammonium bromide, and the photoelectric conversion efficiency (η) was calculated. The result was 4.99%.
　実施例５
　ヘキシルトリメチルアンモニウムブロミドに替えてオクタデシルトリメチルアンモニウムブロミド（東京化成工業（株）製）を用いた他は実施例１と全く同様にして光起電力素子を作製し、光電変換効率（η）を算出した結果、５．３５％であった。 Example 5
A photovoltaic device was produced in the same manner as in Example 1 except that octadecyltrimethylammonium bromide (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of hexyltrimethylammonium bromide, and the photoelectric conversion efficiency (η) was calculated. The result was 5.35%.
　実施例６
　ヘキシルトリメチルアンモニウムブロミド（東京化成工業（株）製）の０．２ｇ／Ｌ　ＩＰＡ溶液に替えて、オクタデシルトリメチルアンモニウムブロミド（東京化成工業（株）製）の２．５ｇ／Ｌ　ＩＰＡ溶液を用いた他は実施例１と全く同様にして光起電力素子を作製し、光電変換効率（η）を算出した結果、４．８０％であった。 Example 6
Other than using 0.2 g / L IPA solution of octadecyltrimethylammonium bromide (manufactured by Tokyo Chemical Industry Co., Ltd.) instead of 0.2 g / L IPA solution of hexyltrimethylammonium bromide (manufactured by Tokyo Chemical Industry Co., Ltd.) Produced a photovoltaic device exactly as in Example 1, and the photoelectric conversion efficiency (η) was calculated to be 4.80%.
　実施例７
　ヘキシルトリメチルアンモニウムブロミド（東京化成工業（株）製）の０．２ｇ／Ｌ　ＩＰＡ溶液に替えて、ポリエチレンイミン（平均分子量１００００）（和研薬（株）製）の０．２ｇ／Ｌ　ＩＰＡ（酢酸０．５％添加）溶液を用いた他は実施例１と全く同様にして光起電力素子を作製し、光電変換効率（η）を算出した結果、４．４３％であった。 Example 7
Instead of 0.2 g / L IPA solution of hexyltrimethylammonium bromide (Tokyo Chemical Industry Co., Ltd.), 0.2 g / L IPA (acetic acid) of polyethyleneimine (average molecular weight 10,000) (manufactured by Waken Pharmaceutical Co., Ltd.) A photovoltaic device was prepared in the same manner as in Example 1 except that the 0.5% addition solution was used, and the photoelectric conversion efficiency (η) was calculated to be 4.43%.
　実施例８
　ヘキシルトリメチルアンモニウムブロミドに替えてヘキサデシルピリジニウムブロミド水和物（東京化成工業（株）製）を用いた他は実施例１と全く同様にして光起電力素子を作製し、光電変換効率（η）を算出した結果、４．６６％であった。 Example 8
A photovoltaic device was prepared in the same manner as in Example 1 except that hexadecylpyridinium bromide hydrate (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of hexyltrimethylammonium bromide, and photoelectric conversion efficiency (η) As a result, it was 4.66%.
　実施例９
　ヘキシルトリメチルアンモニウムブロミドに替えてヘキサデシルジメチル(3-スルホプロピル)アンモニウムヒドロキシド分子内塩（東京化成工業（株）製）を用いた他は実施例１と全く同様にして光起電力素子を作製し、光電変換効率（η）を算出した結果、４．７４％であった。 Example 9
A photovoltaic device was produced in the same manner as in Example 1 except that hexadecyldimethyl (3-sulfopropyl) ammonium hydroxide inner salt (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of hexyltrimethylammonium bromide. The photoelectric conversion efficiency (η) was calculated to be 4.74%.
　実施例１０
　ヘキシルトリメチルアンモニウムブロミドに替えてテトラブチルアンモニウムクロリド（東京化成工業（株）製）を用いた他は実施例１と全く同様にして光起電力素子を作製し、光電変換効率（η）を算出した結果、４．９３％であった。 Example 10
A photovoltaic device was produced in the same manner as in Example 1 except that tetrabutylammonium chloride (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of hexyltrimethylammonium bromide, and the photoelectric conversion efficiency (η) was calculated. The result was 4.93%.
　実施例１１
　ヘキシルトリメチルアンモニウムブロミドに替えてトリブチルヘキサデシルホスホニウムブロミド（東京化成工業（株）製）を用いた他は実施例１と全く同様にして光起電力素子を作製し、光電変換効率（η）を算出した結果、５．００％であった。 Example 11
A photovoltaic device was prepared in the same manner as in Example 1 except that tributylhexadecylphosphonium bromide (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of hexyltrimethylammonium bromide, and the photoelectric conversion efficiency (η) was calculated. As a result, it was 5.00%.
　実施例１２
　ヘキシルトリメチルアンモニウムブロミドに替えて１-ブチル-１-メチルピペリジニウムブロミド（東京化成工業（株）製）を用いた他は実施例１と全く同様にして光起電力素子を作製し、光電変換効率（η）を算出した結果、４．７６％であった。 Example 12
A photovoltaic device was produced in the same manner as in Example 1 except that 1-butyl-1-methylpiperidinium bromide (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of hexyltrimethylammonium bromide, and photoelectric conversion was performed. As a result of calculating the efficiency (η), it was 4.76%.
　実施例１３
　ヘキシルトリメチルアンモニウムブロミドに替えて１-ブチル-３-メチルイミダゾリウムブロミド（東京化成工業（株）製）を用いた他は実施例１と全く同様にして光起電力素子を作製し、光電変換効率（η）を算出した結果、４．６８％であった。 Example 13
A photovoltaic device was prepared in the same manner as in Example 1 except that 1-butyl-3-methylimidazolium bromide (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of hexyltrimethylammonium bromide, and the photoelectric conversion efficiency As a result of calculating (η), it was 4.68%.
　実施例１４
　Ａ－１に替えてＡ－２を用い、Ａ－２を０．２ｍｇ、[７０]ＰＣＢＭを０．８ｍｇ使用して溶液Ａを調製、およびヘキシルトリメチルアンモニウムブロミドに替えてテトラブチルアンモニウムブロミド（東京化成工業（株）製）を用いた他は実施例１と全く同様にして光起電力素子を作製し、光電変換効率（η）を算出した結果、４．８５％であった。 Example 14
Solution A was prepared using A-2 instead of A-1, 0.2 mg of A-2 and 0.8 mg of [70] PCBM, and tetrabutylammonium bromide (Tokyo) instead of hexyltrimethylammonium bromide A photovoltaic device was produced in the same manner as in Example 1 except that Kasei Kogyo Co., Ltd. was used, and the photoelectric conversion efficiency (η) was calculated to be 4.85%.
　実施例１５
　Ａ－１に替えてＡ－２を用い、Ａ－２を０．２ｍｇ、[７０]ＰＣＢＭを０．８ｍｇ使用して溶液Ａを調製、およびヘキシルトリメチルアンモニウムブロミドに替えて下記式で表される化合物（Ｂ－１）とヘプタデカフルオロノナン酸の０．５＋０．５ｇ／Ｌメタノール溶液を用いた他は実施例１と全く同様にして光起電力素子を作製し、光電変換効率（η）を算出した結果、４．８５％であった。 Example 15
A-2 was used instead of A-1, 0.2 mg of A-2 and 0.8 mg of [70] PCBM were used to prepare solution A, and hexyltrimethylammonium bromide was replaced by the following formula A photovoltaic device was produced in the same manner as in Example 1 except that a 0.5 + 0.5 g / L methanol solution of the compound (B-1) and heptadecafluorononanoic acid was used, and the photoelectric conversion efficiency (η) was As a result of calculation, it was 4.85%.
Figure JPOXMLDOC01-appb-C000016
Figure JPOXMLDOC01-appb-C000016
　実施例１６
　Ａ－１に替えてＡ－２を用い、Ａ－２を０．２ｍｇ、[７０]ＰＣＢＭを０．８ｍｇ使用して溶液Ａを調製、およびヘキシルトリメチルアンモニウムブロミドに替えて下記式で表される化合物（Ｂ－２）とヘプタデカフルオロノナン酸の０．５＋０．５ｇ／Ｌメタノール溶液を用いた他は実施例１と全く同様にして光起電力素子を作製し、光電変換効率（η）を算出した結果、４．６９％であった。 Example 16
A-2 was used instead of A-1, 0.2 mg of A-2 and 0.8 mg of [70] PCBM were used to prepare solution A, and hexyltrimethylammonium bromide was replaced by the following formula A photovoltaic device was produced in the same manner as in Example 1 except that a 0.5 + 0.5 g / L methanol solution of the compound (B-2) and heptadecafluorononanoic acid was used, and the photoelectric conversion efficiency (η) was As a result of calculation, it was 4.69%.
Figure JPOXMLDOC01-appb-C000017
Figure JPOXMLDOC01-appb-C000017
　実施例１７
　Ａ－１に替えてＡ－２を用い、Ａ－２を０．２ｍｇ、[７０]ＰＣＢＭを０．８ｍｇ使用して溶液Ａを調製、およびヘキシルトリメチルアンモニウムブロミドに替えて下記式で表される化合物（Ｂ－３）とヘプタデカフルオロノナン酸の０．５＋０．５ｇ／Ｌメタノール溶液を用いた他は実施例１と全く同様にして光起電力素子を作製し、光電変換効率（η）を算出した結果、４．７８％であった。 Example 17
A-2 was used instead of A-1, 0.2 mg of A-2 and 0.8 mg of [70] PCBM were used to prepare solution A, and hexyltrimethylammonium bromide was replaced by the following formula A photovoltaic device was produced in the same manner as in Example 1 except that a 0.5 + 0.5 g / L methanol solution of compound (B-3) and heptadecafluorononanoic acid was used, and the photoelectric conversion efficiency (η) was As a result of calculation, it was 4.78%.
Figure JPOXMLDOC01-appb-C000018
Figure JPOXMLDOC01-appb-C000018
　実施例１８
　Ａ－１に替えてＡ－２を用い、Ａ－２を０．２ｍｇ、[７０]ＰＣＢＭを０．８ｍｇ使用して溶液Ａを調製、およびヘキシルトリメチルアンモニウムブロミドに替えて下記式で表される化合物（Ｂ－４）とヘプタデカフルオロノナン酸の０．５＋０．５ｇ／Ｌメタノール溶液を用いた他は実施例１と全く同様にして光起電力素子を作製し、光電変換効率（η）を算出した結果、４．７２％であった。 Example 18
A-2 was used instead of A-1, 0.2 mg of A-2 and 0.8 mg of [70] PCBM were used to prepare solution A, and hexyltrimethylammonium bromide was replaced by the following formula A photovoltaic device was produced in the same manner as in Example 1 except that a 0.5 + 0.5 g / L methanol solution of compound (B-4) and heptadecafluorononanoic acid was used, and the photoelectric conversion efficiency (η) was As a result of calculation, it was 4.72%.
Figure JPOXMLDOC01-appb-C000019
Figure JPOXMLDOC01-appb-C000019
　実施例１９
　Ａ－１に替えてＡ－２を用い、Ａ－２を０．２ｍｇ、[７０]ＰＣＢＭを０．８ｍｇ使用して溶液Ａを調製、およびヘキシルトリメチルアンモニウムブロミドに替えて下記式で表される化合物（Ｂ－５）とヘプタデカフルオロノナン酸の０．５＋０．５ｇ／Ｌメタノール溶液を用いた他は実施例１と全く同様にして光起電力素子を作製し、光電変換効率（η）を算出した結果、４．８８％であった。 Example 19
A-2 was used instead of A-1, 0.2 mg of A-2 and 0.8 mg of [70] PCBM were used to prepare solution A, and hexyltrimethylammonium bromide was replaced by the following formula A photovoltaic device was prepared in the same manner as in Example 1 except that a 0.5 + 0.5 g / L methanol solution of the compound (B-5) and heptadecafluorononanoic acid was used, and the photoelectric conversion efficiency (η) was As a result of calculation, it was 4.88%.
Figure JPOXMLDOC01-appb-C000020
Figure JPOXMLDOC01-appb-C000020
　実施例２０
　Ａ－１に替えてＡ－２を用い、Ａ－２を０．２ｍｇ、[７０]ＰＣＢＭを０．８ｍｇ使用して溶液Ａを調製、およびヘキシルトリメチルアンモニウムブロミドに替えてＢＣＰとヘプタデカフルオロノナン酸の０．５＋０．５ｇ／Ｌメタノール溶液を用いた他は実施例１と全く同様にして光起電力素子を作製し、光電変換効率（η）を算出した結果、４．７７％であった。 Example 20
Solution A was prepared using A-2 instead of A-1, 0.2 mg A-2 and 0.8 mg [70] PCBM, and BCP and heptadecafluorononane replaced with hexyltrimethylammonium bromide A photovoltaic device was prepared in the same manner as in Example 1 except that a 0.5 + 0.5 g / L methanol solution of acid was used, and the photoelectric conversion efficiency (η) was calculated to be 4.77%. .
　比較例１
　電子取り出し層を設けなかった他は実施例１と全く同様にして光起電力素子を作製し、光電変換効率（η）を算出した結果、３．５９％であった。 Comparative Example 1
A photovoltaic device was produced in the same manner as in Example 1 except that the electron extraction layer was not provided, and the photoelectric conversion efficiency (η) was calculated. As a result, it was 3.59%.
　比較例２
　ヘキシルトリメチルアンモニウムブロミド（東京化成工業（株）製）の０．２ｇ／Ｌ　ＩＰＡ溶液に替えて、ポリエチレンオキシド（平均分子量１０００００）（シグマアルドリッチ社製）の０．５ｇ／Ｌメタノール溶液を用いた他は実施例１と全く同様にして光起電力素子を作製し、光電変換効率（η）を算出した結果、３．６３％であった。 Comparative Example 2
Other than using 0.2 g / L IPA solution of hexyltrimethylammonium bromide (manufactured by Tokyo Chemical Industry Co., Ltd.), 0.5 g / L methanol solution of polyethylene oxide (average molecular weight 100,000) (manufactured by Sigma-Aldrich) was used. Produced a photovoltaic device in exactly the same manner as in Example 1, and the photoelectric conversion efficiency (η) was calculated to be 3.63%.
　比較例３
　ヘキシルトリメチルアンモニウムブロミド（東京化成工業（株）製）の０．２ｇ／Ｌ　ＩＰＡ溶液に替えて、ＰＦＮ（平均分子量１４０００）の１．０ｇ／Ｌメタノール（酢酸１％添加）溶液を用いた他は実施例１と全く同様にして光起電力素子を作製し、光電変換効率（η）を算出した結果、０．０２％であった。 Comparative Example 3
Instead of the 0.2 g / L IPA solution of hexyltrimethylammonium bromide (manufactured by Tokyo Chemical Industry Co., Ltd.), a 1.0 g / L methanol (1% acetic acid added) solution of PFN (average molecular weight 14000) was used. A photovoltaic device was produced in exactly the same manner as in Example 1, and the photoelectric conversion efficiency (η) was calculated. As a result, it was 0.02%.
　比較例４
　Ａ－１に替えてＡ－２を用い、Ａ－２を０．２ｍｇ、[７０]ＰＣＢＭを０．８ｍｇ使用して溶液Ａを調製、および電子取り出し層を設けなかった他は実施例１と全く同様にして光起電力素子を作製し、光電変換効率（η）を算出した結果、４．４６％であった。 Comparative Example 4
A-2 was used instead of A-1, solution A was prepared using 0.2 mg of A-2 and 0.8 mg of [70] PCBM, and except that no electron extraction layer was provided. A photovoltaic device was produced in exactly the same manner, and the photoelectric conversion efficiency (η) was calculated to be 4.46%.
Figure JPOXMLDOC01-appb-T000021
Figure JPOXMLDOC01-appb-T000021
　実施例と比較例の結果を表１にまとめた。実施例１～１３と比較例１～３、実施例１４～２０と比較例４の対比から、本発明により光起電力素子の光電変換効率を向上させることができることが分かる。 The results of Examples and Comparative Examples are summarized in Table 1. From comparison between Examples 1 to 13 and Comparative Examples 1 to 3, and Examples 14 to 20 and Comparative Example 4, it can be seen that the photoelectric conversion efficiency of the photovoltaic device can be improved by the present invention.
１　基板
２　陽極
３　光電変換層
４　電子取り出し層
５　陰極
　 1 Substrate 2 Anode 3 Photoelectric Conversion Layer 4 Electron Extraction Layer 5 Cathode

Claims (6)

  1. 少なくとも陽極、光電変換層、電子取り出し層および陰極をこの順に有する光起電力素子であって、該電子取り出し層が、分子量が１００００以下である下記一般式（１）～（３）で表される化合物群のうち少なくとも一つを含むことを特徴とする光起電力素子。
    Figure JPOXMLDOC01-appb-C000001
     （Ｒ１～Ｒ１１は、それぞれ同じでも異なっていてもよく、水素、置換基を有してもよい炭化水素基、置換基を有してもよい少なくとも酸素、窒素、リン、ケイ素およびホウ素の中から選ばれた一つの元素を含む基、および置換基を有してもよい複素環基の中から選ばれる。ただし、Ｒ５およびＲ８は水素ではない。また、Ｒ１～Ｒ１１は、お互いに独立していても、お互いに結合して環を形成していてもよい。Ａ１～Ａ３は、窒素、リンの中から選ばれる。Ｂ１ －、Ｂ２ －は、Ｆ－、Ｃｌ－、Ｂｒ－、Ｉ－、ＯＨ－、ＢＦ４ －、ＰＦ６ －、ＣｌＯ４ －、ＮＯ３ －、ＣＮ－、ＳＣＮ－、ＨＰＯ４ －、ＰＯ４ ２－、ＳＯ４ ２－、ＣＯ３ ２－、カルボン酸陰イオン、スルホン酸陰イオンの中から選ばれる。Ｘ１は、－ＣＯＯ－、－ＳＯ３ －、－ＰＯ４ －、－ＰＯ４ ２－、－Ｏ－ＳＯ３ －の中から選ばれる。）     A photovoltaic device having at least an anode, a photoelectric conversion layer, an electron extraction layer, and a cathode in this order, and the electron extraction layer is represented by the following general formulas (1) to (3) having a molecular weight of 10,000 or less A photovoltaic device comprising at least one of a compound group.
    Figure JPOXMLDOC01-appb-C000001
     (R 1 to R 11 may be the same or different, and may be hydrogen, a hydrocarbon group that may have a substituent, or at least oxygen, nitrogen, phosphorus, silicon, and boron that may have a substituent. A group containing one element selected from the above and a heterocyclic group which may have a substituent, provided that R 5 and R 8 are not hydrogen, and R 1 to R 11 are A 1 to A 3 may be selected from nitrogen and phosphorus, and B 1 − and B 2 − may be F − , which may be independent from each other or bonded to each other to form a ring. , Cl − , Br − , I − , OH − , BF 4 − , PF 6 − , ClO 4 − , NO 3 − , CN − , SCN − , HPO 4 − , PO 4 2− , SO 4 2− , CO 3 2, selected from the carboxylate anion, sulfonate anion. 1, -COO -, -SO 3 -, -PO 4 -, -PO 4 2-, -O-SO 3 - chosen from among).
  2. 前記一般式（１）～（３）においてＲ１～Ｒ４、Ｒ７、Ｒ９～Ｒ１１がアルキル基、Ｒ８がアルキル鎖であり、Ｒ５およびＲ６が互いに結合して６員環を形成している請求項１記載の光起電力素子。 In the general formulas (1) to (3), R 1 to R 4 , R 7 , R 9 to R 11 are alkyl groups, R 8 is an alkyl chain, and R 5 and R 6 are bonded to each other to form a 6-membered ring. The photovoltaic element according to claim 1, wherein
  3. Ａ１～Ａ３が、窒素である請求項１または２記載の光起電力素子。 3. The photovoltaic element according to claim 1, wherein A 1 to A 3 are nitrogen.
  4. 上記電子取り出し層が、上記分子量が１００００以下である一般式（１）で表される化合物を含む請求項１～３のいずれか記載の光起電力素子。 The photovoltaic element according to any one of claims 1 to 3, wherein the electron extraction layer contains a compound represented by the general formula (1) having the molecular weight of 10,000 or less.
  5. Ｂ１がＢｒである請求項４記載の光起電力素子。 The photovoltaic element according to claim 4, wherein B 1 is Br.
  6. 上記電子取り出し層の膜厚が、０．１ｎｍ～５０ｎｍである請求項１～５のいずれか記載の光起電力素子。 6. The photovoltaic element according to claim 1, wherein the electron extraction layer has a thickness of 0.1 nm to 50 nm.
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WO2006109769A1 (en) * 2005-04-11 2006-10-19 Nippon Kayaku Kabushiki Kaisha Electrolyte composition for photoelectric converter and photoelectric converter using same
US20080251767A1 (en) * 2005-09-13 2008-10-16 Winscom Christoper J Transparent Conductive System
US20070215865A1 (en) * 2006-03-20 2007-09-20 General Electric Company Opto-electronic devices exhibiting enhanced efficiency
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