JP2012079953A - Organic solar cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain both durability and conversion efficiency of a solar cell element by adopting a transparent electrode which is easily manufactured at a lower price than prices of existing transparent electrodes.SOLUTION: The organic solar cell includes a photoelectric conversion layer between at least one pair of electrodes. At least one of the pair of electrodes is a transparent electrode containing a transparent conductive polymer. The transparent electrode contains a water-soluble binder having a structural unit represented by the following general formula (I).

Description

  The present invention relates to an organic solar cell, and more particularly to a reverse layer type organic solar cell that achieves both power generation performance and element durability.

  An organic solar cell (organic photoelectric conversion element) has a power generation layer including a p-type semiconductor and an n-type semiconductor on a transparent electrode, and a charge transport layer that transports generated charges to the electrode, and is formed by light absorption. In this configuration, charges are separated before excitons are deactivated, and the generated charges can be efficiently taken out to the electrode. In recent years, the efficiency has been significantly improved.

  In addition, organic solar cells can be produced by producing a solution containing organic matter by a simple method such as coating or printing, making it ideal for mass production of roll-to-roll, and significantly reducing costs compared to conventional solar cells. Is expected to be the next generation solar cell.

  Generally, transparent electrodes of organic solar cells use metal oxides such as ITO (tin-doped indium oxide), AZO (aluminum-doped zinc oxide), and FTO (fluorine-doped tin oxide), but many of these have poor conductivity. Therefore, the voltage loss due to resistance occurs as the distance from the collecting electrode increases, and the fill factor that determines the performance of the solar cell decreases, which is a problem in increasing the area.

  In response to such problems, attempts have been made to use a metal grid electrode and a conductive polymer as a transparent electrode as an electrode instead of a metal oxide (see, for example, Patent Document 1). In this configuration, although the resistance of the conductive polymer is high, the metal grid electrode efficiently collects electricity as an auxiliary electrode, and therefore, the fill factor is hardly lowered even when the substrate size is increased. In addition, the metal grid itself can be produced by a printing method or the like, and can be said to be an electrode having a high cost merit over the conventional metal oxide electrode.

  On the other hand, an organic solar cell having a so-called reverse layer configuration in which electrons are extracted from the transparent electrode side and holes are extracted from a stable metal electrode side having a deep work function has been proposed (in contrast to a normal organic solar cell) For example, see Patent Literature 2 and Non-Patent Literature 1). Since this structure does not use a metal having a shallow work function that is easily oxidized, it has a feature that the deterioration of the electrode can be suppressed and the device life can be greatly improved.

  However, in any case, there is no disclosure or suggestion of a technology aiming to achieve both durability and conversion efficiency by devising a material constituting the transparent electrode with a conductive polymer.

JP 2009-76668 A JP 2009-146981 A

APPLYED PHYSICS LETTERS, 92,173303,2008

  An object of the present invention is to obtain durability and conversion efficiency of a solar cell element by employing a transparent electrode that is cheaper and easier to manufacture than conventional ones.

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

  1. In an organic solar battery having a photoelectric conversion layer between at least a pair of electrodes, at least one of the pair of electrodes is a transparent electrode containing a transparent conductive polymer, and the transparent electrode is represented by the following general formula (I) An organic solar cell comprising a water-soluble binder having a structural unit represented by:

[Wherein, R represents a hydrogen atom or a methyl group, and Q represents -C (= O) O- or -C (= O) NRa-. Ra represents a hydrogen atom or an alkyl group, and A represents a substituted or unsubstituted alkylene group or — (CH ₂ CHRbO) x —. Rb represents a hydrogen atom or an alkyl group, and x represents the average number of repeating units. ]
2. 2. The organic solar cell according to 1 above, wherein the water-soluble binder has both a structural unit represented by the general formula (I) and a structural unit represented by the following general formula (II).

[Wherein, R, Q, and A represent the same groups as R, Q, and A in formula (I). y represents 0 or 1; Z represents an alkyl group, —C (═O) —Rc, —SO ₂ —Rd, —SiRe ₃ . Rc, Rd and Re each independently represents an alkyl group, a perfluoroalkyl group or an aryl group. ]
3. 3. The organic solar cell according to 1 or 2, wherein the organic solar cell has at least one auxiliary electrode adjacent to the transparent electrode.

  4). 4. The organic solar cell according to any one of 1 to 3, wherein the organic solar cell is a reverse layer type solar cell.

  According to the present invention, an organic photoelectric conversion element that achieves an excellent fill factor and an open circuit voltage even in a large area, and has excellent element durability at high temperatures and high humidity, and an organic solar cell using the organic photoelectric conversion element are provided. We were able to.

It is sectional drawing which illustrated the solar cell element of this invention.

  The best mode for carrying out the present invention will be described in detail below, but the present invention is not limited thereto.

<Transparent electrode>
The transparent electrode in the present invention is formed into a film by applying and drying a dispersion of a conductive polymer on a substrate to be described later or an auxiliary electrode (described later) provided on the substrate. In particular, it contains a water-soluble binder having a conductive polymer and a structural unit represented by the general formula (I). The water-soluble binder having the structural unit represented by the general formula (I) has an effect of enhancing the conductivity of the conductive polymer, and thereby can simultaneously satisfy high conductivity and high transparency.

  In addition to the above-mentioned printing methods such as gravure printing, flexographic printing, and screen printing, transparent electrodes are applied in roll coating, bar coating, dip coating, spin coating, casting, die coating, blades Coating methods such as a coating method, a bar coating method, a gravure coating method, a curtain coating method, a spray coating method, a doctor coating method, and an ink jet method can be used.

  The ratio of the conductive polymer and the water-soluble binder in the transparent electrode coating solution is preferably 30 to 900 parts by weight of the water-soluble binder when the conductive polymer is 100 parts by weight. From the viewpoint of the conductivity enhancing effect and transparency of the conductive binder, the water-soluble binder is more preferably 100 parts by mass or more.

  The dry film thickness of the transparent electrode is preferably 30 nm to 2000 nm. From the viewpoint of conductivity, the thickness is more preferably 100 nm or more, and from the viewpoint of the surface smoothness of the electrode, it is further preferably 200 nm or more. Moreover, it is more preferable that it is 1000 nm or less from the point of transparency.

  After applying the transparent electrode coating solution, a drying treatment can be appropriately performed. Although there is no restriction | limiting in particular as conditions of a drying process, It is preferable to dry-process at the temperature of the range which does not damage a base material or a conductive layer. Further, by performing heat treatment, the crosslinking reaction of the water-soluble binder can be promoted and completed. Thereby, the cleaning resistance and solvent resistance of the electrode are remarkably improved, and the device performance is improved. In particular, in an organic EL element, effects such as reduction in driving voltage and improvement in life can be obtained. The drying step and the heat treatment step may be the same step or may be performed separately. In the case of separate processes, drying and heat treatment may be continuous, and there may be a time pause between the two processes.

  There are no restrictions on the conditions of the drying process and the heat treatment process, but for example, drying can be performed at a temperature of 80 ° C. or higher, for example, as a condition that allows rapid evaporation of moisture, and the upper limit is a temperature at which the conductive layer is not damaged. Up to about 300 ° C is considered a possible region. The time is preferably in the range of about 10 seconds to 10 minutes. Further, the heat treatment is preferably performed at a temperature of 150 ° C. or higher and 300 ° C. or lower. If it is less than 150 ° C., the reaction promoting effect is small, and if it exceeds 300 ° C., the effect is small because thermal damage to the material increases. The heat treatment time is preferably 1 minute or longer. The upper limit of the treatment time is not particularly limited, but is preferably 24 hours or less from the viewpoint of productivity. However, when the heat treatment temperature exceeds 200 ° C., it is preferable to keep it within 30 minutes. The heat treatment may be performed on-line or off-line after applying and drying the conductive layer. In the case of off-line, it is preferable to further perform under reduced pressure because it leads to accelerated drying of moisture.

  In the present invention, the crosslinking reaction of the hydroxyl group-containing nonconductive polymer can be promoted and completed using an acid catalyst. As the acid catalyst, hydrochloric acid, sulfuric acid or ammonium sulfate can be used. Moreover, in the polyanion used as a dopant for a conductive polymer, a dopant and a catalyst can be used together by using a sulfo group-containing polyanion. In addition, the heat treatment described above can be performed in combination with the use of an acid catalyst, which is preferable because it shortens the treatment time.

<Binder resin>
The binder resin according to the present invention is a water-soluble binder having a structure containing the structural unit represented by the general formula (I). The water-soluble binder mentioned in the present invention may be a binder resin that dissolves about 0.001 g in 100 g of water at 25 ° C.

  The degree of solubility in water can be measured with a haze meter or a turbidimeter. Further, the water-soluble binder resin according to the present invention more preferably has a structure containing both the structural unit represented by the general formula (I) and the structural unit represented by the general formula (II).

  In the structural unit represented by the general formula (I) of the present invention, R represents a hydrogen atom or a methyl group.

  Q represents —C (═O) O— or —C (═O) NRa—, and Ra represents a hydrogen atom or an alkyl group. The alkyl group is preferably a linear or branched alkyl group having 1 to 5 carbon atoms, and more preferably a methyl group. These alkyl groups may be substituted with a substituent. Examples of these substituents include alkyl groups, cycloalkyl groups, aryl groups, heterocycloalkyl groups, heteroaryl groups, hydroxy groups, halogen atoms, alkoxy groups, alkylthio groups, arylthio groups, cycloalkoxy groups, aryloxy groups, Acyl group, alkylcarbonamide group, arylcarbonamide group, alkylsulfonamide group, arylsulfonamide group, ureido group, aralkyl group, nitro group, alkoxycarbonyl group, aryloxycarbonyl group, aralkyloxycarbonyl group, alkylcarbamoyl group, Arylcarbamoyl group, alkylsulfamoyl group, arylsulfamoyl group, acyloxy group, alkenyl group, alkynyl group, alkylsulfonyl group, arylsulfonyl group, alkyloxysulfonyl , Aryloxy sulfonyl group, alkylsulfonyloxy group, may be substituted with an aryl sulfonyloxy group. Of these, a hydroxy group and an alkyloxy group are preferable.

  The alkyl group may have a branch, and the number of carbon atoms is preferably 1 to 20, more preferably 1 to 12, and still more preferably 1 to 8. Examples of the alkyl group include methyl group, ethyl group, propyl group, isopropyl group, butyl group, t-butyl group, hexyl group, octyl group and the like.

  The number of carbon atoms of the cycloalkyl group is preferably 3-20, more preferably 3-12, and still more preferably 3-8. Examples of the cycloalkyl group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group. The alkoxy group may have a branch, and the number of carbon atoms is preferably 1 to 20, more preferably 1 to 12, still more preferably 1 to 6, and further preferably 1 to 4. Most preferably. Examples of the alkoxy group include a methoxy group, an ethoxy group, a 2-methoxyethoxy group, a 2-methoxy-2-ethoxyethoxy group, a butyloxy group, a hexyloxy group and an octyloxy group, and preferably an ethoxy group. The number of carbon atoms of the alkylthio group may be branched, and the number of carbon atoms is preferably 1 to 20, more preferably 1 to 12, still more preferably 1 to 6, Most preferably, it is 1-4. Examples of the alkylthio group include a methylthio group and an ethylthio group. The arylthio group preferably has 6 to 20 carbon atoms, and more preferably 6 to 12 carbon atoms. Examples of the arylthio group include a phenylthio group and a naphthylthio group. The number of carbon atoms of the cycloalkoxy group is preferably 3-12, more preferably 3-8. Examples of the cycloalkoxy group include a cyclopropoxy group, a cyclobutoxy group, a cyclopentyloxy group, and a cyclohexyloxy group. The aryl group preferably has 6 to 20 carbon atoms, and more preferably 6 to 12 carbon atoms. Examples of the aryl group include a phenyl group and a naphthyl group. The aryloxy group preferably has 6 to 20 carbon atoms, and more preferably 6 to 12 carbon atoms. Examples of the aryloxy group include a phenoxy group and a naphthoxy group. The heterocycloalkyl group preferably has 2 to 10 carbon atoms, and more preferably 3 to 5 carbon atoms. Examples of the heterocycloalkyl group include a piperidino group, a dioxanyl group, and a 2-morpholinyl group. The number of carbon atoms in the heteroaryl group is preferably 3-20, and more preferably 3-10. Examples of the heteroaryl group include a thienyl group and a pyridyl group. The acyl group preferably has 1 to 20 carbon atoms, and more preferably 1 to 12 carbon atoms. Examples of the acyl group include a formyl group, an acetyl group, and a benzoyl group. The alkylcarbonamide group preferably has 1 to 20 carbon atoms, and more preferably 1 to 12 carbon atoms. Examples of the alkylcarbonamide group include an acetamide group. The arylcarbonamide group preferably has 1 to 20 carbon atoms, and more preferably 1 to 12 carbon atoms. Examples of the arylcarbonamide group include a benzamide group and the like. The alkylsulfonamide group preferably has 1 to 20 carbon atoms, and more preferably 1 to 12 carbon atoms. Examples of the sulfonamido group include a methanesulfonamido group and the like, and the arylsulfonamido group preferably has 1 to 20 carbon atoms, and more preferably 1 to 12 carbon atoms. Examples of the arylsulfonamide group include a benzenesulfonamide group and p-toluenesulfonamide group. The number of carbon atoms in the aralkyl group is preferably 7-20, and more preferably 7-12. Examples of the aralkyl group include a benzyl group, a phenethyl group, and a naphthylmethyl group. The alkoxycarbonyl group preferably has 1 to 20 carbon atoms, more preferably 2 to 12 carbon atoms. Examples of the alkoxycarbonyl group include a methoxycarbonyl group. The aryloxycarbonyl group preferably has 7 to 20 carbon atoms, and more preferably 7 to 12 carbon atoms. Examples of the aryloxycarbonyl group include a phenoxycarbonyl group. The aralkyloxycarbonyl group preferably has 8 to 20 carbon atoms, and more preferably 8 to 12 carbon atoms. Examples of the aralkyloxycarbonyl group include a benzyloxycarbonyl group. The acyloxy group preferably has 1 to 20 carbon atoms, and more preferably 2 to 12 carbon atoms. Examples of the acyloxy group include an acetoxy group and a benzoyloxy group. The alkenyl group has preferably 2 to 20 carbon atoms, and more preferably 2 to 12 carbon atoms. Examples of the alkenyl group include vinyl group, allyl group and isopropenyl group. The alkynyl group preferably has 2 to 20 carbon atoms, and more preferably 2 to 12 carbon atoms. Examples of the alkynyl group include an ethynyl group. The alkylsulfonyl group preferably has 1 to 20 carbon atoms, and more preferably 1 to 12 carbon atoms. Examples of the alkylsulfonyl group include a methylsulfonyl group and an ethylsulfonyl group. The arylsulfonyl group preferably has 6 to 20 carbon atoms, and more preferably 6 to 12 carbon atoms. Examples of the arylsulfonyl group include a phenylsulfonyl group and a naphthylsulfonyl group. The alkyloxysulfonyl group preferably has 1 to 20 carbon atoms, and more preferably 1 to 12 carbon atoms. Examples of the alkyloxysulfonyl group include a methoxysulfonyl group and an ethoxysulfonyl group. The aryloxysulfonyl group preferably has 6 to 20 carbon atoms, and more preferably 6 to 12 carbon atoms. Examples of the aryloxysulfonyl group include a phenoxysulfonyl group and a naphthoxysulfonyl group. The alkylsulfonyloxy group preferably has 1 to 20 carbon atoms, and more preferably 1 to 12 carbon atoms. Examples of the alkylsulfonyloxy group include a methylsulfonyloxy group and an ethylsulfonyloxy group.

  The number of carbon atoms of the arylsulfonyloxy group is preferably 6-20, and more preferably 6-12. Examples of the arylsulfonyloxy group include a phenylsulfonyloxy group and a naphthylsulfonyloxy group. The substituents may be the same or different, and these substituents may be further substituted.

In the structural unit represented by the general formula (I) of the present invention, A represents a substituted or unsubstituted alkylene group, — (CH ₂ CHRbO) _x —. The alkylene group preferably has, for example, 1 to 5 carbon atoms, more preferably an ethylene group or a propylene group. These alkylene groups may be substituted with the above-described substituents. R _b represents a hydrogen atom or an alkyl group. The alkyl group is preferably a linear or branched alkyl group having 1 to 5 carbon atoms, and more preferably a methyl group. Further, these alkyl groups may be substituted with the above-described substituents. Furthermore, x represents the average number of repeating units, preferably 1 to 100, more preferably 1 to 10. The number of repeating units has a distribution, the notation indicates an average value, and may be expressed by one digit after the decimal point.

  In the structural unit represented by the general formula (II) of the present invention, R, Q and A have the same meaning as defined in the general formula (I).

In the structural unit represented by the general formula (II) of the present invention, y represents 0 or 1. Z represents an alkyl group, —C (═O) —Rc, —SO ₂ —Rd, —SiRe ₃ , and the alkyl group preferably has, for example, 1 to 12 carbon atoms, more preferably a methyl group or an ethyl group. And more preferably a methyl group. These alkyl groups may be substituted with the substituent described above. Rc, Rd, and Re represent an alkyl group, a perfluoroalkyl group, and an aryl group. The alkyl group preferably has, for example, 1 to 12 carbon atoms, more preferably a methyl group or an ethyl group, and still more preferably a methyl group. . These alkyl groups may be substituted with the substituent described above. The perfluoroalkyl group preferably has, for example, 1 to 8 carbon atoms, more preferably a trifluoromethyl group or a pentafluoroethyl group, still more preferably a trifluoromethyl group. The aryl group is preferably, for example, a phenyl group or a toluyl group, and more preferably a toluyl group. Furthermore, these alkyl groups, perfluoroalkyl groups, and aryl groups may be substituted with the above-described substituents.

  Typical examples of the structural units represented by general formula (I) and general formula (II) are shown below, but the present invention is not limited thereto.

  The binder resin of the present invention may contain a structural unit in addition to the structural unit represented by the general formula (I) and the structural unit represented by the general formula (II).

  In the binder resin according to the present invention, the molar ratio of the structural unit having a hydroxy group represented by the general formula (I) is preferably 10 to 90%, more preferably 50 to 80%. Moreover, 1-50% of the molar ratio of the structural unit which does not have a hydroxy group represented by general formula (II) is preferable, More preferably, it is 10-30%.

  The binder resin of the present invention can be obtained by radical polymerization using a general-purpose polymerization catalyst. Examples of the polymerization mode include bulk polymerization, solution polymerization, suspension polymerization, emulsion polymerization and the like, preferably solution polymerization. The polymerization temperature varies depending on the initiator used, but is generally -10 to 250 ° C, preferably 0 to 200 ° C, more preferably 10 to 100 ° C.

  The molecular weight of the binder resin of the present invention is preferably in the range of 3,000 to 2,000,000, more preferably 4,000 to 500,000, and still more preferably 5,000 to 100,000.

The number average molecular weight and molecular weight distribution of the binder resin of the present invention can be measured by generally known gel permeation chromatography (GPC). The solvent to be used is not particularly limited as long as the binder resin dissolves, and THF (tetrahydrofuran), DMF (dimethylformamide), and CH ₂ Cl ₂ are preferable, more preferably THF and DMF, and still more preferably DMF. The measurement temperature is not particularly limited, but 40 ° C. is preferable.

<Conductive polymer>
In the present invention, the transparent conductive layer contains a conductive polymer.

  The conductive polymer according to the present invention is a conductive polymer having a π-conjugated conductive polymer and a polyanion. Such a conductive polymer can be easily produced by chemical oxidative polymerization of a precursor monomer that forms a π-conjugated conductive polymer described later in the presence of an appropriate oxidizing agent, an oxidation catalyst, and a poly anion described later. .

(Π-conjugated conductive polymer)
The π-conjugated conductive polymer used in the present invention is not particularly limited, and includes polythiophenes (including basic polythiophenes, the same applies hereinafter), polypyrroles, polyindoles, polycarbazoles, polyanilines, polyacetylenes, polyfurans. , Polyparaphenylene vinylenes, polyazulenes, polyparaphenylenes, polyparaphenylene sulfides, polyisothianaphthenes, polythiazyl chain conductive polymers can be used. Of these, polythiophenes and polyanilines are preferable from the viewpoints of conductivity, transparency, stability, and the like. Most preferred is polyethylene dioxythiophene.

(Π-conjugated conductive polymer precursor monomer)
Precursor monomers used in the formation of π-conjugated conductive polymers have a π-conjugated system in the molecule, and even when polymerized by the action of an appropriate oxidant, a π-conjugated system is formed in the main chain. It is what is done. Examples thereof include pyrroles and derivatives thereof, thiophenes and derivatives thereof, anilines and derivatives thereof, and the like.

  Specific examples of the precursor monomer include pyrrole, 3-methylpyrrole, 3-ethylpyrrole, 3-n-propylpyrrole, 3-butylpyrrole, 3-octylpyrrole, 3-decylpyrrole, 3-dodecylpyrrole, 3, 4-dimethylpyrrole, 3,4-dibutylpyrrole, 3-carboxylpyrrole, 3-methyl-4-carboxylpyrrole, 3-methyl-4-carboxyethylpyrrole, 3-methyl-4-carboxybutylpyrrole, 3-hydroxypyrrole 3-methoxypyrrole, 3-ethoxypyrrole, 3-butoxypyrrole, 3-hexyloxypyrrole, 3-methyl-4-hexyloxypyrrole, thiophene, 3-methylthiophene, 3-ethylthiophene, 3-propylthiophene, 3 -Butylthiophene, 3-hexylchi Phen, 3-heptylthiophene, 3-octylthiophene, 3-decylthiophene, 3-dodecylthiophene, 3-octadecylthiophene, 3-bromothiophene, 3-chlorothiophene, 3-iodothiophene, 3-cyanothiophene, 3-phenyl Thiophene, 3,4-dimethylthiophene, 3,4-dibutylthiophene, 3-hydroxythiophene, 3-methoxythiophene, 3-ethoxythiophene, 3-butoxythiophene, 3-hexyloxythiophene, 3-heptyloxythiophene, 3- Octyloxythiophene, 3-decyloxythiophene, 3-dodecyloxythiophene, 3-octadecyloxythiophene, 3,4-dihydroxythiophene, 3,4-dimethoxythiophene, 3,4-diethoxythiol 3,4-dipropoxythiophene, 3,4-dibutoxythiophene, 3,4-dihexyloxythiophene, 3,4-diheptyloxythiophene, 3,4-dioctyloxythiophene, 3,4-didecyloxy Thiophene, 3,4-didodecyloxythiophene, 3,4-ethylenedioxythiophene, 3,4-propylenedioxythiophene, 3,4-butenedioxythiophene, 3-methyl-4-methoxythiophene, 3-methyl -4-ethoxythiophene, 3-carboxythiophene, 3-methyl-4-carboxythiophene, 3-methyl-4-carboxyethylthiophene, 3-methyl-4-carboxybutylthiophene, aniline, 2-methylaniline, 3-isobutyl Aniline, 2-aniline sulfonic acid, 3-aniline A sulfonic acid etc. are mentioned.

(Poly anion)
The polyanion used in the present invention includes a substituted or unsubstituted polyalkylene, a substituted or unsubstituted polyalkenylene, a substituted or unsubstituted polyimide, a substituted or unsubstituted polyamide, a substituted or unsubstituted polyester, and a co-polymer thereof. A polymer comprising a structural unit having an anionic group and a structural unit having no anionic group.

  This poly anion is a solubilized polymer that solubilizes the π-conjugated conductive polymer in a solvent. The anion group of the polyanion functions as a dopant for the π-conjugated conductive polymer, and improves the conductivity and heat resistance of the π-conjugated conductive polymer.

  The anion group of the polyanion may be any functional group capable of causing chemical oxidation doping to the π-conjugated conductive polymer. Among them, from the viewpoint of ease of production and stability, a monosubstituted sulfate ester Group, monosubstituted phosphate group, phosphate group, carboxy group, sulfo group and the like are preferable. Furthermore, from the viewpoint of the doping effect of the functional group on the π-conjugated conductive polymer, a sulfo group, a monosubstituted sulfate group, and a carboxy group are more preferable.

  Specific examples of polyanions include polyvinyl sulfonic acid, polystyrene sulfonic acid, polyallyl sulfonic acid, polyacrylic acid ethyl sulfonic acid, polyacrylic acid butyl sulfonic acid, poly-2-acrylamido-2-methylpropane sulfonic acid, poly Isoprene sulfonic acid, polyvinyl carboxylic acid, polystyrene carboxylic acid, polyallyl carboxylic acid, polyacryl carboxylic acid, polymethacryl carboxylic acid, poly-2-acrylamido-2-methylpropane carboxylic acid, polyisoprene carboxylic acid, polyacrylic acid, etc. Can be mentioned. These homopolymers may be sufficient and 2 or more types of copolymers may be sufficient.

  Further, it may be a poly anion further having F (fluorine atom) in the compound. Specifically, Nafion (made by Dupont) containing a perfluorosulfonic acid group, Flemion (made by Asahi Glass Co., Ltd.) made of perfluoro vinyl ether containing a carboxylic acid group, and the like can be mentioned.

  Among these, the compound having a sulfonic acid is formed by applying and drying the conductive polymer-containing layer, and then subjected to a heat drying treatment at 100 to 120 ° C. for 5 minutes or more before irradiating the microwave. May be. This promotes the crosslinking reaction, which is preferable since the washing resistance and solvent resistance of the coating film are remarkably improved.

  Furthermore, among these, polystyrene sulfonic acid, polyisoprene sulfonic acid, polyacrylic acid ethylsulfonic acid, and polyacrylic acid butylsulfonic acid are preferable. These poly anions have high compatibility with the hydroxy group-containing non-conductive polymer, and can further increase the conductivity of the obtained conductive polymer.

  The degree of polymerization of the polyanion is preferably in the range of 10 to 100,000 monomer units, and more preferably in the range of 50 to 10,000 from the viewpoint of solvent solubility and conductivity.

  Examples of the method for producing a polyanion include a method of directly introducing an anionic group into a polymer having no anionic group using an acid, a method of sulfonating a polymer having no anionic group with a sulfonating agent, and an anionic group containing The method of manufacturing by superposition | polymerization of a polymerizable monomer is mentioned.

  Examples of the method for producing an anionic group-containing polymerizable monomer by polymerization include a method for producing an anionic group-containing polymerizable monomer in a solvent by oxidative polymerization or radical polymerization in the presence of an oxidizing agent and / or a polymerization catalyst. Specifically, a predetermined amount of the anionic group-containing polymerizable monomer is dissolved in a solvent, kept at a constant temperature, and a solution in which a predetermined amount of an oxidizing agent and / or a polymerization catalyst is dissolved in the solvent is added to the predetermined amount. React with time. The polymer obtained by the reaction is adjusted to a certain concentration by the solvent. In this production method, an anionic group-containing polymerizable monomer may be copolymerized with a polymerizable monomer having no anionic group.

  The oxidizing agent, oxidation catalyst, and solvent used in the polymerization of the anionic group-containing polymerizable monomer are the same as those used in the polymerization of the precursor monomer that forms the π-conjugated conductive polymer.

  When the obtained polymer is a polyanionic salt, it is preferably transformed into a polyanionic acid. Examples of the method for converting to an anionic acid include an ion exchange method using an ion exchange resin, a dialysis method, an ultrafiltration method, and the like. Among these, the ultrafiltration method is preferable from the viewpoint of easy work.

  The ratio of π-conjugated conductive polymer and polyanion contained in the conductive polymer, “π-conjugated conductive polymer”: “polyanion”, is preferably 1: 1 to 20 in mass ratio. From the viewpoint of conductivity and dispersibility, the range of 1: 2 to 10 is more preferable.

The oxidant used when the precursor monomer forming the π-conjugated conductive polymer is chemically oxidatively polymerized in the presence of the polyanion to obtain the conductive polymer according to the present invention is, for example, J. Org. Am. Soc. 85, 454 (1963), which is suitable for the oxidative polymerization of pyrrole. For practical reasons, cheap and easy to handle oxidants such as iron (III) salts, eg FeCl ₃ , Fe (ClO ₄ ) ₃ , organic acids and iron (III) salts of inorganic acids containing organic residues Or use hydrogen peroxide, potassium dichromate, alkali persulfate (eg potassium persulfate, sodium persulfate) or ammonium, alkali perborate, potassium permanganate and copper salts such as copper tetrafluoroborate preferable. In addition, air and oxygen in the presence of catalytic amounts of metal ions such as iron, cobalt, nickel, molybdenum and vanadium ions can be used as oxidants at any time. The use of persulfates and the iron (III) salts of inorganic acids containing organic acids and organic residues has great application advantages because they are not corrosive.

  Examples of iron (III) salts of inorganic acids containing organic residues include iron (III) salts of alkanol sulfate half esters of alkanols such as lauryl sulfate; alkyl sulfonic acids of 1 to 20 carbons such as Methane or dodecanesulfonic acid; carboxylic acid having 1 to 20 aliphatic carbon atoms such as 2-ethylhexylcarboxylic acid; aliphatic perfluorocarboxylic acid such as trifluoroacetic acid and perfluorooctanoic acid; aliphatic dicarboxylic acid such as oxalic acid And in particular aromatic (optionally) alkyl-substituted sulfonic acids having 1 to 20 carbon atoms, such as the Fe (III) salts of benzenecenesulfonic acid, p-toluenesulfonic acid and dodecylbenzenesulfonic acid.

  As such a conductive polymer, a commercially available material can also be preferably used. For example, a conductive polymer (abbreviated as PEDOT-PSS) composed of poly (3,4-ethylenedioxythiophene) and polystyrenesulfonic acid is described in H.C. C. It is commercially available from Starck as the Clevios series, from Aldrich as PEDOT-PSS 483095, 560596, and from Nagase Chemtex as the Denatron series. Polyaniline is also commercially available from Nissan Chemical as the ORMECON series. In the present invention, such an agent can also be preferably used.

  An organic compound may be contained as the second dopant. There is no restriction | limiting in particular in the organic compound which can be used by this invention, It can select suitably from well-known things, For example, an oxygen containing compound is mentioned suitably. The oxygen-containing compound is not particularly limited as long as it contains oxygen, and examples thereof include a hydroxy group-containing compound, a carbonyl group-containing compound, an ether group-containing compound, and a sulfoxide group-containing compound. Examples of the hydroxy group-containing compound include ethylene glycol, diethylene glycol, propylene glycol, trimethylene glycol, 1,4-butanediol, and glycerin. Among these, ethylene glycol and diethylene glycol are preferable. Examples of the carbonyl group-containing compound include isophorone, propylene carbonate, cyclohexanone, and γ-butyrolactone. Examples of the ether group-containing compound include diethylene glycol monoethyl ether. Examples of the sulfoxide group-containing compound include dimethyl sulfoxide. These may be used alone or in combination of two or more, but at least one selected from dimethyl sulfoxide, ethylene glycol, and diethylene glycol is preferably used.

<Additive>
Examples of the additive include plasticizers, stabilizers such as antioxidants and sulfurization inhibitors, surfactants, dissolution accelerators, polymerization inhibitors, and colorants such as dyes and pigments. Furthermore, from the viewpoint of improving workability such as coating properties, solvents (for example, organic solvents such as water, alcohols, glycols, cellosolves, ketones, esters, ethers, amides, hydrocarbons, etc.) are used. May be included.

[Transparent substrate]
The transparent substrate used in the present invention is not particularly limited as a material to be applied as long as it has high light transmittance and excellent flexibility. For example, a glass substrate is excellent in terms of light transmittance. Conventionally, glass has a thickness of several mm or more, and flexibility has not been obtained. However, in recent years, it has become possible to form glass with an extremely thin film thickness of 1 mm or less, and a flexible glass plate has been developed. Such a glass plate can be used as a transparent substrate. A transparent resin film excellent in flexibility is also preferably used.

  There is no restriction | limiting in particular in the transparent resin film which can be preferably used as a transparent base material by this invention, About the material, a shape, a structure, thickness, etc., it can select suitably from well-known things. For example, polyolefins such as polyester resin films such as polyethylene terephthalate (PET), polyethylene naphthalate, and modified polyester, polyethylene (PE) resin films, polypropylene (PP) resin films, polystyrene (PS) resin films, and cyclic olefin resins. Resin films, vinyl resin films such as polyvinyl chloride (PVC) and polyvinylidene chloride, polyether ether ketone (PEEK) resin films, polysulfone (PSF) resin films, polyether sulfone (PES) resin films, polycarbonate (PC ) Resin film, polyamide resin film, polyimide resin film, acrylic resin film, triacetyl cellulose (TAC) resin film, etc. If the resin film transmittance of 80% or more in length (380 to 780 nm), can be preferably applied to a transparent resin film according to the present invention. Among these, in terms of transparency, heat resistance, ease of handling, strength and cost, biaxially stretched polyethylene terephthalate (PET) film, biaxially stretched polyethylene naphthalate (PEN) film, polyethersulfone (PES) film, polycarbonate ( PC) film, and more preferably a biaxially stretched polyethylene terephthalate film and a biaxially stretched polyethylene naphthalate film.

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

  Examples of the easy adhesion layer include polyester, polyamide, polyurethane, vinyl copolymer, butadiene copolymer, acrylic copolymer, vinylidene copolymer, and epoxy copolymer. The easy adhesion layer may be a single layer, but may be composed of two or more layers in order to improve adhesion.

Further, an inorganic or organic film or a hybrid film of both may be formed on the front or back surface of the transparent substrate, and the water vapor transmission rate (25 ± 0) measured by a method in accordance with JIS K 7129-1992. .5 ° C., relative humidity (90 ± 2)% RH) is preferably a barrier film of 1 × 10 ⁻³ g / (m ² · 24 h) or less, and further conforms to JIS K 7126-1987. The oxygen permeability measured by the above method is 1 × 10 ⁻³ ml / m ² · 24 h · atm or less (1 atm is 1.01325 × 10 ⁵ Pa), water vapor permeability (25 ± 0.5 ° C. , Relative humidity (90 ± 2)% RH) is preferably a high barrier film having 1 × 10 ⁻³ g / (m ² · 24 h) or less.

  As a material for forming a barrier film formed on the front surface or the back surface of a transparent substrate in order to obtain a high barrier film, it has a function of suppressing the intrusion of elements that affect the deterioration of organic EL elements such as moisture and oxygen. Any material can be used. For example, silicon oxide, silicon dioxide, silicon nitride, or the like can be used. In order to further improve the brittleness of the barrier film, it is more preferable to form a laminated structure of these inorganic layers and layers made of an organic material. Although there is no restriction | limiting in particular about the lamination | stacking order of an inorganic layer and an organic layer, It is preferable to laminate | stack both alternately several times.

《Auxiliary electrode》
The auxiliary electrode according to the present invention is provided adjacent to the transparent conductive layer. Specifically, a method of forming a transparent conductive layer after forming an auxiliary electrode on a substrate, a method of forming an auxiliary electrode after forming a transparent conductive layer on a substrate, and a transparent formed on a temporary substrate It can also be provided by transferring the conductive layer and the auxiliary electrode to the substrate.

  The auxiliary electrode is preferably formed of a material having higher conductivity than the transparent conductive layer. There is no restriction | limiting in particular as such a material, For example, alloys other than metals, such as gold | metal | money, silver, copper, iron, nickel, chromium, may be sufficient. In particular, the shape of the metal material is preferably metal fine particles or metal nanowires from the viewpoint of ease of pattern formation as described later, and the metal material is preferably silver from the viewpoint of conductivity.

  Since these materials are generally opaque to light, it is desirable to provide the auxiliary electrode in a pattern having an opening.

  The pattern shape is not particularly limited, but may be, for example, a stripe shape, a lattice shape, a honeycomb shape, or a random network shape, and a stripe shape, a lattice shape, or a honeycomb shape is particularly preferable.

  The line width of the pattern is preferably 10 to 200 μm. If the line width of the fine wire is less than 10 μm, it is difficult to obtain desired conductivity, and if it exceeds 200 μm, the transparency is remarkably lowered. More preferably, it is the range of 10-100 micrometers.

  In the stripe-like and lattice-like patterns, the interval between the fine lines is preferably 0.5 to 4 mm. In the honeycomb pattern, the length of one side is preferably 0.5 to 4 mm.

  The height of the thin wire is preferably 0.1 to 10 μm. If the height of the thin wire is less than 0.1 μm, desired conductivity cannot be obtained, and if it exceeds 10 μm, current leakage and the thickness of the functional layer increase in the formation of an organic electronic device, causing a distribution failure.

  The pattern of the auxiliary electrode according to the present invention can be formed by a printing method such as a gravure printing method, a flexographic printing method, and a screen printing method using a dispersion of metal particles. For each printing method, a method generally used for electrode pattern formation can be applied to the present invention. Specific examples include gravure printing methods described in JP2009-295980, JP2009-259826, JP2009-96189, and JP2009-90662, and flexographic printing methods in JP2004-268319. Examples of the method described in JP-A No. 2003-168560, and examples of the screen printing method include methods described in JP-A 2010-34161, JP-A 2010-10245, and JP-A 2009-302345.

  As another method, for example, a metal layer can be formed on the entire surface of the substrate, and can be formed by a known photolithography method. Specifically, a conductor layer is formed on the entire surface using one or more physical or chemical forming methods such as printing, vapor deposition, sputtering, plating, etc., or a metal foil is used as an adhesive. After being laminated on the base material, the film can be processed into a desired stripe shape or mesh shape by etching using a known photolithography method.

  As another method, a method of printing an ink containing metal fine particles in a desired shape by screen printing, or applying a plating catalyst ink to a desired shape by gravure printing or an ink jet method, followed by plating treatment As another method, a method using silver salt photographic technology can also be used. A method using silver salt photographic technology can be carried out with reference to, for example, [0076]-[0112] of JP-A-2009-140750 and Examples. About the method of carrying out the gravure printing of catalyst ink and plating, it can carry out with reference to Unexamined-Japanese-Patent No. 2007-281290, for example.

  As a random network structure, for example, a method for spontaneously forming a disordered network structure of conductive fine particles by applying and drying a liquid containing metal fine particles as described in JP-T-2005-530005 Can be used.

  The surface specific resistance of the thin wire portion of the first conductive layer is preferably 100Ω / □ or less, and more preferably 10Ω / □ or less. The surface specific resistance can be measured based on, for example, JIS K6911, ASTM D257, etc., and can be easily measured using a commercially available surface resistivity meter.

(Metal nanoparticles)
The auxiliary electrode pattern is preferably provided by printing a paste of metal particles. After printing, in order to increase conductivity, heating and baking are performed. When a PET film is used as the substrate, the firing temperature is preferably 110 ° C. or lower. The metal particles are preferably metal nanoparticles because high conductivity is obtained.

  The metal nanoparticles refer to fine metal particles having a particle size of from atomic scale to nm size. As an average particle diameter of a metal nanoparticle, 3-300 nm is preferable and it is more preferable that it is 5-100 nm. The metal used in the metal nanoparticles according to the present invention is preferably silver or copper from the viewpoint of conductivity, and may be silver or copper alone, or a combination of them, either silver and copper alloy, silver or copper. It may be plated with any metal. Among these, silver nanoparticles are particularly preferable. Among these, silver nanoparticles having an average particle size of 30 nm or less are preferable.

  The auxiliary electrode formed on the substrate is preferably subjected to a heat baking treatment. This is particularly preferable because the fusion of the metal fine particles proceeds and the first conductive layer becomes highly conductive. The temperature for heating and baking is preferably in the range of 100 to 900 ° C, more preferably in the range of 150 to 600 ° C. The preferred range of the heat firing time varies depending on the temperature, but is preferably 1 to 60 minutes.

<Counter electrode>
On the other hand, as the counter electrode, a metal, an alloy, an electrically conductive compound and a mixture thereof are preferably used. However, metals and the like do not need to be thin films, and there are no particular limitations on the film thickness and composition as long as desired electrical conductivity can be obtained. Further, it is preferable to select a material having an optimum work function according to the charge transport layer in contact therewith. As a specific material, the same material as the example mentioned in the above-mentioned transparent electrode can be used.

  In the case of a configuration in which electrons are extracted from the counter electrode side, it is more preferable to select a material having a shallower work function from the above-described materials so that electrons can be efficiently extracted.

  The organic solar cell of the present invention needs to have at least a power generation layer between at least the transparent electrode and the counter electrode.

  As a power generation layer, either a conventional junction of a p-type semiconductor layer and an n-type semiconductor layer or a bulk heterojunction layer (also referred to as a BHJ layer or an i-layer) in which a p-type semiconductor and an n-type semiconductor are mixed is used. But you can use it.

<P-type semiconductor material>
Examples of the p-type semiconductor material used for the power generation layer of the present invention include various condensed polycyclic aromatic low molecular compounds and conjugated polymers.

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

  Examples of the derivative having the above-mentioned condensed polycycle include WO 03/16599 pamphlet, WO 03/28125 pamphlet, US Pat. No. 6,690,029, JP 2004-107216 A. A pentacene derivative having a substituent described in JP-A No. 2003-136964, a pentacene precursor described in US Patent Application Publication No. 2003/136964, and the like; Amer. Chem. Soc. , Vol127. No. 14.4986, J. MoI. Amer. Chem. Soc. , Vol. 123, p9482; Amer. Chem. Soc. , Vol. 130 (2008), no. 9, acene-based compounds substituted with a trialkylsilylethynyl group described in 2706 and the like.

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

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

  Among these compounds, compounds that have high solubility in organic solvents to the extent that solution processing is possible, can form a crystalline thin film after drying, and can achieve high mobility are preferable.

  Further, when the electron transport layer is formed on the power generation layer by coating, there is a problem that the electron transport layer solution dissolves the power generation layer. Therefore, a material that can be insolubilized after coating by a solution process may be used. .

  Examples of such materials include materials that can be insolubilized by polymerizing the coating film after coating, such as polythiophene having a polymerizable group described in Technical Digest of the International PVSEC-17, Fukuoka, Japan, 2007, P1225. Or a material in which soluble substituents react and become insoluble (pigmented) by applying energy such as heat, as described in US Patent Application Publication No. 2003/136964, and Japanese Patent Application Laid-Open No. 2008-16834 And so on.

<N-type semiconductor material>
The n-type semiconductor material used for the power generation layer of the present invention is not particularly limited. For example, fullerene, octaazaporphyrin, and other p-type semiconductor perfluoro products (perfluoropentacene, perfluorophthalocyanine, etc.), naphthalenetetracarboxylic Examples thereof include aromatic carboxylic acid anhydrides such as acid anhydrides, naphthalenetetracarboxylic acid diimides, perylenetetracarboxylic acid anhydrides, and perylenetetracarboxylic acid diimides, and polymer compounds containing the imidized product thereof as a skeleton.

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

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

<Charge transport layer: hole transport layer, electron transport layer>
The original function of the charge transport layer is to serve as a blocking layer that transports only holes or electrons generated in the power generation layer to the electrode and prevents transport of the opposite carrier. In this case, the hole transport layer can be referred to as an electron blocking layer, and the electron transport layer as a hole blocking layer.

  The hole blocking layer has a function of an electron transport layer in a broad sense. More specifically, the hole blocking layer is made of a hole blocking material having a function of transporting electrons and having a remarkably small ability to transport holes, and transports electrons. While blocking holes, the recombination probability of electrons and holes on the electrode can be improved. Moreover, the structure of the electron carrying layer mentioned later can be used as a hole-blocking layer concerning this invention as needed. The hole blocking layer is preferably provided adjacent to the power generation layer.

  On the other hand, the electron blocking layer has a function of a hole transport layer in a broad sense. More specifically, the electron blocking layer is made of a material that has a function of transporting holes and has an extremely small ability to transport electrons, and transports holes. However, the probability of recombination of electrons and holes can be improved by blocking electrons. Moreover, the structure of the positive hole transport layer mentioned later can be used as an electron blocking layer as needed.

  As described above, the dry film thickness of the charge transport layer of the present invention is preferably 30 to 2000 nm. In particular, the charge transport layer (for example, 104 in FIG. 1) on the electrode forming side later preferably has a thickness of 100 nm or more from the viewpoint of suppressing damage during electrode formation, and 200 nm or more from the viewpoint of further improving the leakage prevention effect. More preferably, the film thickness is Moreover, it is more preferable that it is a film thickness of 1000 nm or less from a viewpoint of maintaining the high transmittance | permeability and the resistance reduction as a film | membrane.

  On the other hand, the charge transport layer on the substrate side (for example, 102 in FIG. 1) is preferably 5 to 500 nm, more preferably 7 to 200 nm, and most preferably 10 to 100 nm from the viewpoint of film resistance and transmittance. .

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

  The hole transport material has any one of hole injection or transport and electron barrier properties, and may be either organic or inorganic. For example, triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives and pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, Examples thereof include stilbene derivatives, silazane derivatives, aniline copolymers, and conductive polymer oligomers, particularly thiophene oligomers.

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

  Furthermore, a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used. In addition, inorganic compounds such as p-type-Si, p-type-SiC, nickel oxide, and molybdenum oxide can also be used as the hole injection material and the hole transport material.

  JP-A-11-251067, J. Org. Huang et. al. A so-called p-type hole transport material described in a book (Applied Physics Letters 80 (2002), p. 139) can also be used.

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

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

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

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

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

  In addition, n-type conductive inorganic oxides (titanium oxide, zinc oxide, etc.) can also be used.

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

[Intermediate electrode]
The intermediate electrode material required in the case of the tandem structure is preferably a layer using a compound having both transparency and conductivity, and the materials (ITO, AZO, FTO, etc.) used in the transparent electrode , Transparent metal oxides such as titanium oxide, very thin metal layers such as Ag, Al, Au, or layers containing nanoparticles / nanowires, conductive polymer materials such as PEDOT: PSS, polyaniline, etc.) it can.

  In addition, in the hole transport layer and the electron transport layer described above, there is also a combination that works as an intermediate electrode (charge recombination layer) by appropriately combining and laminating, and with such a configuration, the process of forming one layer This is preferable because it can be omitted.

(substrate)
When light that is photoelectrically converted enters from the substrate side, the substrate is preferably a member that can transmit the light that is photoelectrically converted, that is, a member that is transparent to the wavelength of the light to be photoelectrically converted. As the substrate, for example, a glass substrate, a resin substrate and the like are preferably mentioned, but it is desirable to use a transparent resin film from the viewpoint of light weight and flexibility. There is no restriction | limiting in particular in the transparent resin film which can be preferably used as a transparent substrate by this invention, The material, a shape, a structure, thickness, etc. can be suitably selected from well-known things. For example, polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN) modified polyester, polyethylene (PE) resin film, polypropylene (PP) resin film, polystyrene resin film, polyolefin resins such as cyclic olefin resin Film, vinyl resin film such as polyvinyl chloride, polyvinylidene chloride, polyether ether ketone (PEEK) resin film, polysulfone (PSF) resin film, polyether sulfone (PES) resin film, polycarbonate (PC) resin film, A polyamide resin film, a polyimide resin film, an acrylic resin film, a triacetyl cellulose (TAC) resin film, and the like can be given. If the resin film transmittance of 80% or more at ~800nm), can be preferably applied to a transparent resin film according to the present invention. Among these, from the viewpoint of transparency, heat resistance, ease of handling, strength and cost, it is preferably a biaxially stretched polyethylene terephthalate film, a biaxially stretched polyethylene naphthalate film, a polyethersulfone film, or a polycarbonate film, and biaxially stretched. More preferred are polyethylene terephthalate films and biaxially stretched polyethylene naphthalate films.

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

  Further, for the purpose of suppressing the permeation of oxygen and water vapor, a barrier coat layer may be formed in advance on the transparent substrate, or a hard coat layer may be formed in advance on the opposite side to which the transparent conductive layer is transferred. Good.

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

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

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

  As an example of the microlens array, quadrangular pyramids having a side of 30 μm and an apex angle of 90 degrees are two-dimensionally arranged on the light extraction side of the substrate. One side is preferably 10 to 100 μm. If it is smaller than this, the effect of diffraction is generated and colored.

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

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

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

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

  The power generation layer (bulk heterojunction layer) may be composed of a layer in which a p-type semiconductor and an n-type semiconductor are mixed, but may have a plurality of layers or a gradation composition with a mixture ratio different in the film thickness direction.

(Other functional layers)
For the purpose of improving the sunlight utilization rate (photoelectric conversion efficiency), an element is formed on a pair of comb-shaped electrodes instead of the sandwiched structure between the first electrode and the second electrode as shown in FIG. The back contact type organic photoelectric conversion element can also be configured.

  Furthermore, although not shown in FIG. 1, it is good also as a structure which has various intermediate | middle layers in an element for the purpose of the improvement of energy conversion efficiency and the improvement of element lifetime. Examples of the intermediate layer include a hole injection layer, an electron injection layer, an exciton block layer, a UV absorption layer, a light reflection layer, a wavelength conversion layer, a smoothing layer, and the like.

  If a metal material is used as the conductive material of the counter electrode, the light coming to the counter electrode side is reflected and reflected to the first electrode side, and this light can be reused and is absorbed again by the photoelectric conversion layer, and more photoelectric conversion is performed. Efficiency is improved and preferable.

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

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

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

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

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

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

  As a transparent electrode support substrate, a PET film (manufactured by Toyobo, thickness 125 μm) and a thin blue plate glass (manufactured by Asahi Glass, thickness 100 μm) were prepared.

Production of Auxiliary Electrode On each substrate, a silver nanoparticle paste 1 (M-Dot SLP made by Mitsuboshi Belting) was used, using a gravure printing tester K303MULTICOATER made by RK Print Coat Instruments Ltd., line width 50 μm, height 0.8 μm, spacing. After printing a 1.0 mm fine wire grid, a drying process was performed at 110 ° C. for 5 minutes to produce an auxiliary electrode.

<Formation of transparent electrode layer>
A transparent electrode layer coating solution shown in Table 1 having the following composition was applied onto each substrate in a pattern with an applicator so as to have a wet film thickness of 10 μm, including the presence or absence of auxiliary electrodes. The area of the pattern was 20 mm square at the position covering the auxiliary electrode. The substrate after the pattern application was dried at 90 ° C. for 1 minute using a circulating thermostat. Thereafter, the heat treatment described in Table 1 was performed using an electric furnace to form a transparent electrode layer.

(Transparent electrode layer coating composition)
π-conjugated conductive polymer dispersion (Clevios TH510; manufactured by HC Starck, solid content 1.7% by mass)
17.6g
Water-soluble binder aqueous solution (Table 1 listed; adjusted to a solid content of 20% by mass) 3.5 g
Dimethyl sulfoxide 1.0g
<Synthesis example>
<Synthesis of water-soluble binder resin>
Synthesis Example 1 (Synthesis of P-1: within the present invention)
After adding 100 ml of THF to a 200 ml three-necked flask and heating to reflux for 10 minutes, the mixture was cooled to room temperature under nitrogen. I-1: 2-hydroxyethyl acrylate (1.74 g, 15 mmol, molecular weight: 116.05), II-6: Blemmer PME-200 (9.7 g, 35 mmol, molecular weight: 276.16), AIBN (0.8 g) 5 mmol, molecular weight: 164.11) was added, and the mixture was heated to reflux for 5 hours. After cooling to room temperature, the reaction solution was dropped into 3000 ml of MEK (methyl ethyl ketone) and stirred for 1 hour. After decantation of MEK, the polymer was washed 3 times with 100 ml of MEK, and then the polymer was dissolved in THF and transferred to a 100 ml flask. THF was distilled off under reduced pressure using a rotary evaporator and then dried under reduced pressure at 50 ° C. for 3 hours. As a result, 10.3 g (yield 90%) of water-soluble binder resin P-1 having a number average molecular weight of 33700 and a molecular weight distribution of 2.4 was obtained.

  The molecular weight was measured by GPC (Waters 2695, manufactured by Waters).

<GPC measurement conditions>
Apparatus: Wagers 2695 (Separations Module)
Detector: Waters 2414 (Refractive Index Detector)
Column: Shodex Asahipak GF-7M HQ
Eluent: Dimethylformamide (20 mM LiBr)
Flow rate: 1.0 ml / min
Temperature: 40 ° C
Synthesis Example 2 (Synthesis of P-2: within the present invention)
Except for using I-5: Blemmer AE-90 (7.20 g, 45 mmol, molecular weight: 160.07), II-4: methoxyethoxyethyl acrylate (0.87 g, 5 mmol, molecular weight: 174.09) as monomers. By the same method as in Synthesis Example 1, 7.10 g (yield 88%) of water-soluble binder resin P-2 having a number average molecular weight of 29200 and a molecular weight distribution of 2.6 was obtained.

Synthesis Example 3 (Synthesis of P-3: within the present invention)
Except for using I-8: Blemmer AE-200 (7.10 g, 25 mmol, molecular weight: 284.16), II-21: N-methylacrylamide (2.13 g, 25 mmol, molecular weight: 85.05) as monomers. By the same method as in Synthesis Example 1, 7.75 g (yield 84%) of water-soluble binder resin P-3 having a number average molecular weight of 31700 and a molecular weight distribution of 2.1 was obtained.

Synthesis Example 4 (Synthesis of P-4: within the present invention)
Except that I-12: Blemmer PP-500 (3.04 g, 5 mmol, molecular weight: 608.41), II-7: Blemmer PME-400 (22.3 g, 45 mmol, molecular weight: 276.16) were used as monomers. In the same manner as in Synthesis Example 1, 22.0 g (yield 87%) of water-soluble binder resin P-4 having a number average molecular weight of 33200 and a molecular weight distribution of 2.7 was obtained.

Synthesis Example 5 (Synthesis of P-5: within the present invention)
Synthesis Example except that I-13: Blemmer GLM (2.19 g, 15 mmol, molecular weight: 146.06), II-12: Blemmer AE-400 (16.9 g, 35 mmol, molecular weight: 482.27) were used as monomers. 1) 17.4 g (yield 91%) of water-soluble binder resin P-5 having a number average molecular weight of 23100 and a molecular weight distribution of 2.7 was obtained.

Synthesis Example 6 (Synthesis of P-6: within the present invention)
After adding 200 ml of THF to a 500 ml three-necked flask and heating to reflux for 10 minutes, it was cooled to room temperature under nitrogen. 2-hydroxyethyl acrylate (10.0 g, 86 mmol, molecular weight: 116.05) and AIBN (1.41 g, 8.5 mmol, molecular weight: 164.11) were added, and the mixture was heated to reflux for 5 hours. After cooling to room temperature, the reaction solution was added dropwise into 5000 ml of MEK and stirred for 1 hour. After decantation of MEK, the polymer was washed 3 times with 200 ml of MEK, and then the polymer was dissolved in THF and transferred to a 100 ml flask. THF was distilled off under reduced pressure using a rotary evaporator and then dried under reduced pressure at 50 ° C. for 3 hours. As a result, 9.0 g (yield 90%) of water-soluble binder resin Z having a number average molecular weight of 35700 and a molecular weight distribution of 2.3 was obtained.

  A water-soluble binder resin Z3.0 g and dehydrated tetrahydrofuran 30 ml were charged into a 100 ml flask and completely dissolved, and then the internal temperature was reduced to 10 ° C. or lower with an ice bath. A solution prepared by dissolving trifluoromethanesulfonyl chloride (0.65 g, 3.9 mmol, molecular weight: 167.93) in 10 ml of dehydrated tetrahydrofuran was separately prepared, and dropped into the water-soluble binder resin Z solution over 30 minutes. The internal temperature was maintained at 10 ° C. or lower. After stirring for 1 hour after completion of the dropwise addition, the solution was filtered with a filter paper, and the resulting solution was concentrated to 10 ml by a rotary evaporator. The reaction solution was added dropwise to 300 ml of ethyl alcohol and stirred for 1 hour, 150 ml of diisopropyl ether was added, and the mixture was further stirred for 1 hour. After decantation of the solution, the polymer was washed with 100 ml of diisopropyl ether three times, and then the polymer was dissolved in THF and transferred to a 50 ml flask. THF was distilled off under reduced pressure using a rotary evaporator and then dried under reduced pressure at 50 ° C. for 3 hours. As a result, 3.18 g (yield 87%) of water-soluble binder resin P-6 having a number average molecular weight of 30700 and a molecular weight distribution of 2.1 was obtained.

Synthesis Example 7 (Synthesis of P-7: within the present invention)
A number average molecular weight of 32,200 and a molecular weight distribution of 2.200 were obtained in the same manner as in Synthesis Example 6 except that p-toluenesulfonyl chloride (0.30 g, 1.9 mmol, molecular weight: 154.002) was used instead of trifluoromethanesulfonyl chloride. 0, 2.97 g (90% yield) of water-soluble binder resin P-7 was obtained.

Synthesis Example 8 (Synthesis of P-8: within the present invention)
I-15: N-methylolacrylamide (0.25 g, 2.5 mmol, molecular weight: 101.05), II-6: Blemmer PME-200 (13.1 g, 47.5 mmol, molecular weight: 276.16) as monomers 11.7 g (yield 88%) of a water-soluble binder resin P-8 having a number average molecular weight of 35900 and a molecular weight distribution of 2.7 was obtained in the same manner as in Synthesis Example 1 except that it was used.

Synthesis Example 9 (Synthesis of P-9: within the present invention)
Synthesis Example 1 except that I-19: hydroxyethylacrylamide (0.58 g, 5 mmol, molecular weight: 115.06) and II-24: acryloylmorpholine (6.35 g, 45 mmol, molecular weight: 141.08) were used as monomers. By the same method, 6.03 g (yield 87%) of water-soluble binder resin P-9 having a number average molecular weight of 35,900 and a molecular weight distribution of 2.7 was obtained.

Synthesis Example 10 (Synthesis of P-10: within the present invention)
4.50 g of binder resin P-10 having a number average molecular weight of 37000 and a molecular weight distribution of 2.7 was obtained in the same manner as in Synthesis Example 1 except that 5.01 g of only I-1 was used as a monomer (yield 89%). Obtained.

Synthesis Example 11 (Synthesis of P-11: within the present invention)
4.80 g of binder resin P-11 having a number average molecular weight of 39000 and a molecular weight distribution of 2.8 was obtained in the same manner as in Synthesis Example 1 except that 5.33 g of only I-19 was used as a monomer (yield 90%). Obtained.

Synthesis Example 12 (Synthesis of P-12: within the present invention)
According to the same method as in Synthesis Example 1 except that 2-hydroxyethyl acrylate (3.48 g, 30 mmol, molecular weight: 116.05) and acrylic acid (2.16 g, 30 mmol, molecular weight: 72.02) were used as monomers. 4.29 g (yield 76%) of binder resin P-12 having a number average molecular weight of 37100 and a molecular weight distribution of 2.6 was obtained using a resin having a hydroxy group.

Formation of solar cell elements SC-101 to 115 (normal layer)
On the electrodes of each of the transparent substrates 1 to 15, polythiophene (P3HT; poly-3-hexylthiophene-2,5-diyl (resiregular)) and fullerene derivative (PCBM; 1- (3-methoxycarbonyl) propyl-1- Phenyl (6,6) -C ₆₀ ) was dissolved in chlorobenzene so that the polythiophene concentration was 1.0 mass% and the fullerene concentration was 0.4 mass% to prepare a coating solution for a photoelectric conversion layer. Next, this photoelectric conversion layer coating solution was applied on the conductive polymer layer by a spin coating method at a rotation speed of 700 rpm. Then, it was made to dry at 110 degreeC for 10 minute (s), and the photoelectric converting layer was formed.

  Next, a Ca thin film (film thickness: 30 nm) and an Al thin film (film thickness: 80 nm) were sequentially formed on the photoelectric conversion layer by a vapor deposition method to form a metal electrode.

  Finally, sealing was performed from above the metal electrode with a sealing glass material and an adhesive sealing material, so that solar cell elements SC-101 to 115 were produced.

Formation of solar cell elements SC-201 to 215 (reverse layer)
On each of the transparent electrodes 1 to 15, o-dichlorobenzene and P3HT (manufactured by BASF: regioregular poly-3-hexylthiophene) and PCBM (manufactured by Frontier Carbon: 6,6-phenyl-C61-butylic) (Acid methyl ester) is mixed at 1: 0.8 so as to be 3.0% by mass, filtered through a filter and manufactured as a photoelectric conversion layer on the transparent electrode so that the dry film thickness is about 200 nm. Filmed.

  Subsequently, PEDOT-PSS (manufactured by Clevios P 4083, HC Starck Co., Ltd.) composed of a conductive polymer and a polyanion, a solution containing Emulgen, isopropanol manufactured by Kao Chemical Co., Ltd., and a dry film thickness of about 100 nm The coating was dried so that Thereafter, heat treatment was performed at 150 ° C. for 10 minutes to form a hole transport layer.

The substrate on which the series of functional layers is formed is moved into a vacuum deposition apparatus chamber, the pressure inside the vacuum deposition apparatus is reduced to 1 × 10 ⁻⁴ Pa or less, and then Ag metal is deposited at a deposition rate of 5.0 nm / second. A second electrode was formed by stacking 200 nm. The obtained organic photoelectric conversion element was moved to a nitrogen chamber and sealed using a sealing cap and a UV curable resin, so that a solar cell element SC-201 to 215 having a light receiving portion of about 10 × 10 mm size was produced. did.

<Evaluation of device performance>
About the produced element, the light of 100 mW / cm ² intensity of solar simulator (AM1.5G filter) is irradiated, a mask with an effective area of 1 cm ² is superimposed on the light receiving part, and the IV characteristics are evaluated, thereby short-circuiting. The current density Jsc (mA / cm ² ), the open circuit voltage Voc (V), and the fill factor FF are average values obtained by measuring four light receiving portions formed on the same element, respectively, and are further multiplied to obtain the nominal conversion efficiency. PCE ₀ (%) was obtained.

Furthermore, after storing for 100 hours in an environment of 85 ° C. of each element, the nominal conversion efficiency PCE ₁₀₀ (%) was obtained in the same manner again. The results are shown in Table 2.

  From this result, it can be seen that high conversion efficiency and element storage stability can be obtained by using the transparent electrode having the configuration of the present invention.

  In the present invention, a grid-like auxiliary electrode is used. However, it has been confirmed that an element can be similarly formed in a stripe shape, a honeycomb shape, or the like, and the effect of the present invention can be obtained.

100 Example of Preferred Solar Cell Element of the Present Invention 101 Base Material 103 Transparent Electrode Layer (First Electrode)
104 Electron Transport Layer 105 Photoelectric Conversion Layer 106 Hole Transport Layer 107 Second Electrode 200 Example of Preferred Solar Cell Element of the Present Invention 201 Base Material 202 Metal Grid Electrode 203 Transparent Electrode Layer (First Electrode)
204 Electron transport layer 205 Photoelectric conversion layer 206 Hole transport layer 207 Second electrode

Claims (4)

In an organic solar battery having a photoelectric conversion layer between at least a pair of electrodes, at least one of the pair of electrodes is a transparent electrode containing a transparent conductive polymer, and the transparent electrode is represented by the following general formula (I) An organic solar cell comprising a water-soluble binder having a structural unit represented by:

[Wherein, R represents a hydrogen atom or a methyl group, and Q represents -C (= O) O- or -C (= O) NRa-. Ra represents a hydrogen atom or an alkyl group, and A represents a substituted or unsubstituted alkylene group or — (CH ₂ CHRbO) x —. Rb represents a hydrogen atom or an alkyl group, and x represents the average number of repeating units. ] 2. The organic solar cell according to claim 1, wherein the water-soluble binder has both a structural unit represented by the general formula (I) and a structural unit represented by the following general formula (II).

[Wherein, R, Q, and A represent the same groups as R, Q, and A in formula (I). y represents 0 or 1; Z represents an alkyl group, —C (═O) —Rc, —SO ₂ —Rd, —SiRe ₃ . Rc, Rd and Re each independently represents an alkyl group, a perfluoroalkyl group or an aryl group. ]   The organic solar cell according to claim 1, further comprising at least one auxiliary electrode adjacent to the transparent electrode.   The said organic solar cell is a reverse layer type solar cell, The organic solar cell of any one of Claim 1 to 3 characterized by the above-mentioned.

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