JP2006278583A - Organic thin-film solar cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic thin-film solar cell, having a hole extraction layer and exhibiting high photoelectric conversion efficiency. <P>SOLUTION: The organic thin film solar cell comprises a substrate, a first electrode layer formed on the substrate, a hole extraction layer formed on the first electrode layer, a photoelectric conversion layer formed on the hole extraction layer, and a second electrode layer formed on the photoelectric conversion layer, wherein the hole extraction layer contains a conductive polymer material and a low molecular weight compound with an unpaired electron. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an organic thin film solar cell having a hole extraction layer and improved photoelectric conversion efficiency.

  An organic thin film solar cell is a solar cell in which an organic thin film having an electron donating function and an electron accepting function is disposed between two different electrodes, and has a manufacturing process compared to an inorganic solar cell represented by silicon or the like. It has an advantage that it is easy and can be enlarged at low cost. However, since the photoelectric conversion efficiency is low, it has been difficult to put it into practical use. Therefore, in the organic thin-film solar cell, increasing the photoelectric conversion efficiency is the biggest issue.

  Moreover, as a general organic thin film solar cell, for example, a transparent substrate, a transparent electrode layer, a photoelectric conversion layer that functions as an electron donor and an electron acceptor, and a counter electrode layer are sequentially laminated. . In the organic thin film solar cell in which a plurality of layers are laminated in this manner, the smoothness, adhesion, etc. at the interface between the transparent electrode layer and the photoelectric conversion layer have a great influence on the performance of the solar cell. Since the extraction of electric charges in organic thin-film solar cells is not actively assisted by an external electric field, the presence of slight defects or barriers in the charge transfer path greatly impairs the characteristics of the solar cell, and the transparent electrode layer This is because interfacial resistance caused by smoothness, adhesion, and the like at the interface between the surface and the photoelectric conversion layer becomes a defect or a barrier. In general, since the transparent electrode layer is formed by vapor deposition or the like, the surface state varies, and the smoothness, adhesion, etc. at the interface between the transparent electrode layer and the photoelectric conversion layer are reduced, resulting in a short circuit current. This is the cause of the decrease in value.

  In order to improve the photoelectric conversion efficiency and improve the smoothness and adhesion at the interface between the transparent electrode layer and the photoelectric conversion layer, a hole extraction layer is provided between the transparent electrode layer and the photoelectric conversion layer. Is effective (see, for example, Patent Document 1). By providing this hole extraction layer, the hole extraction efficiency from the photoelectric conversion layer to the transparent electrode layer is increased, the photoelectric conversion efficiency is improved, the interface resistance is decreased, the short-circuit current value is increased, and the solar cell The performance can be improved.

In general, the hole extraction layer is a layer made of a conductive polymer material, and polyethylene dioxythiophene (PEDOT) or the like is mainly used as the conductive polymer material. Conventionally, a conductive polymer material such as PEDOT has been used for a hole injection layer of an organic electroluminescence element. In the organic electroluminescence element, since it is necessary to suppress the diffusion of the light emitting region due to the injection of electrons into the hole injection layer, it is required to suppress the conductivity of the hole injection layer to some extent. On the other hand, in an organic thin film solar cell, it is required to effectively take out holes generated in the photoelectric conversion layer to an external circuit. For this reason, when the conductive polymer material used for the hole injection layer of the organic electroluminescence element is used as it is for the hole extraction layer of the organic thin film solar cell element, sufficient conductivity may not be obtained.
Therefore, even in an organic thin-film solar cell having a hole extraction layer, a problem remains in improving the photoelectric conversion efficiency.

JP 2002-76384 A

  The present invention has been made in view of the above problems, and is an organic thin film solar cell having a hole extraction layer, the main object of which is to provide an organic thin film solar cell with high photoelectric conversion efficiency. is there.

  As a result of intensive studies in view of the above circumstances, the present inventors can obtain high photoelectric conversion efficiency by forming a hole extraction layer containing a low molecular compound having unpaired electrons in addition to the conductive polymer material. As a result, the present invention has been completed.

  That is, the present invention includes a substrate, a first electrode layer formed on the substrate, a hole extraction layer formed on the first electrode layer, and a photoelectric conversion formed on the hole extraction layer. An organic thin film solar cell having a layer and a second electrode layer formed on the photoelectric conversion layer, wherein the hole extraction layer comprises a conductive polymer material and a low molecular compound having unpaired electrons. An organic thin film solar cell containing the organic thin film solar cell is provided.

  In the present invention, since the hole extraction layer contains a low molecular compound having an unpaired electron together with the conductive polymer material, the low molecular compound can be used even when the conductivity of the conductive polymer material is not sufficient. It is considered that the movement of holes is facilitated by electron donation by unpaired electrons. As a result, the formation of a hole transmission path in the hole extraction layer is promoted, so that the hole extraction efficiency is improved, and this is considered to improve the photoelectric conversion efficiency.

  At this time, the low molecular compound having an unpaired electron preferably contains nitrogen.

  In the present invention, the hole extraction layer preferably contains a resin component. When the hole extraction layer contains a resin component, the dispersibility of the conductive polymer material in the hole extraction layer and the film formation property of the hole extraction layer are improved, so that the conductivity of the hole extraction layer is improved. This is because it is considered that the smoothness and adhesion at the interface between the hole extraction layer and the first electrode layer or photoelectric conversion layer can be improved. In addition, many resin components do not have conductivity, and if a non-conductive material is contained in the hole extraction layer, the hole extraction efficiency may be reduced. This is because the low molecular weight compound facilitates the movement of holes, so that the effects of the present invention are remarkably exhibited.

  In this case, it is preferable that the resin component has a high affinity with the conductive polymer material. This is because it is considered that the dispersibility of the conductive polymer material can be effectively improved by using a resin component having a high affinity with the conductive polymer material.

  Furthermore, in the present invention, the hole extraction layer preferably contains an amphiphilic material. Since the hole extraction layer contains an amphiphilic material, the dispersibility of the conductive polymer material and the wettability of the surface of the hole extraction layer are improved. Therefore, the hole extraction layer and the first electrode layer or the photoelectric conversion layer are improved. This is because it is considered that the conductivity of the hole extraction layer can be effectively improved together with the smoothness and adhesion at the interface with the surface.

  At this time, the amphiphilic material is preferably a nonionic surfactant or a fluorosurfactant.

  Moreover, in this invention, it is preferable that the electron extraction layer is formed between the said photoelectric converting layer and the said 2nd electrode layer. Thereby, since the electron extraction efficiency from the photoelectric conversion layer to the second electrode layer is increased, the photoelectric conversion efficiency can be further improved.

  In the present invention, it is considered that the hole extraction layer contains a low molecular compound having unpaired electrons in addition to the conductive polymer material, so that the movement of holes can be facilitated, and high photoelectric conversion is achieved. There is an effect that efficiency can be achieved. Such technology is not limited to organic thin-film solar cells, but can be expected to be widely applied to various devices such as optical sensors and optical communications.

Hereinafter, the organic thin film solar cell of the present invention will be described in detail.
A. Organic thin film solar cell The organic thin film solar cell of the present invention comprises a substrate, a first electrode layer formed on the substrate, a hole extraction layer formed on the first electrode layer, and the hole extraction layer. An organic thin film solar cell having a photoelectric conversion layer formed thereon and a second electrode layer formed on the photoelectric conversion layer, wherein the hole extraction layer is formed of a conductive polymer material and an unpaired electron And a low molecular weight compound having the above.

  In the present invention, since the hole extraction layer contains a low molecular compound having unpaired electrons, even if the conductivity of the conductive polymer material is not sufficient, electrons due to the unpaired electrons of the low molecular compound. It is considered that the movement of the holes becomes smooth by the donation, the formation of the hole transmission path in the hole extraction layer is promoted, and the conductivity of the hole extraction layer is improved. Therefore, improvement in hole extraction efficiency can be expected.

  FIG. 1 is a cross-sectional view showing an example of the organic thin film solar cell of the present invention. As illustrated in FIG. 1, the organic thin film solar cell 10 of the present invention includes a substrate 1, a first electrode layer 2, a hole extraction layer 3, a photoelectric conversion layer 4, and a second electrode layer 5 sequentially. It is a laminated one.

  In general, it is assumed that the conductive polymer material easily aggregates due to its large molecular weight and forms an aggregate. The aggregate of the conductive polymer material is likely to be secondarily aggregated, and the conductive polymer material may be localized between the first electrode layer and the photoelectric conversion layer. In this case, it is difficult to sufficiently form a hole transmission path, and the conductivity of the hole extraction layer may be reduced.

In such a case, the hole extraction layer preferably contains a resin component. As illustrated in FIG. 2, when the hole extraction layer 3 contains the resin component 14 together with the conductive polymer material and the low-molecular compound having unpaired electrons, the aggregate 11 of the conductive polymer material becomes secondary. This is because it is considered that the aggregation 11 of the conductive polymer material can be dispersed in the hole extraction layer 3 by preventing aggregation.
However, many of the above resin components do not have conductivity, and if a non-conductive material is contained in the hole extraction layer, the hole extraction efficiency may be lowered. In the present invention, since the hole extraction layer contains the low molecular compound having unpaired electrons as described above, the hole extraction layer 3 is formed by the low molecular compound 12 having unpaired electrons as illustrated in FIG. It is considered that the formation of the hole transfer path 13 is promoted.
Therefore, the dispersibility of the conductive polymer material in the hole extraction layer is improved, and the formation of the hole transfer path is promoted, so that the conductivity of the hole extraction layer is increased and the hole extraction efficiency is effective. It is thought that it can be improved.

Thus, when the hole extraction layer contains a non-conductive material such as a resin component, the low-molecular compound having unpaired electrons facilitates the movement of holes. The effect is remarkable.
Hereinafter, each structure of the organic thin-film solar cell of this invention is demonstrated.

1. Hole Extraction Layer The hole extraction layer used in the present invention contains a conductive polymer material and a low molecular compound having unpaired electrons.

  As the conductive polymer material used in the present invention, those generally used for the hole extraction layer can be used. Specifically, conductive organic compounds such as doped polyaniline, polyphenylene vinylene, polythiophene, polypyrrole, polyparaphenylene, polyacetylene and triphenyldiamine, or electron donating compounds such as tetrathiofulvalene and tetramethylphenylenediamine And an organic material that forms a charge transfer complex composed of an electron-accepting compound such as tetracyanoquinodimethane and tetracyanoethylene.

  Among the above, polythiophene is preferable, and a mixture (PEDOT / PSS) of polyethylenedioxythiophene (PEDOT) and polystyrene sulfonate (PSS) is particularly preferable.

  Further, the low molecular compound having an unpaired electron used in the present invention is not particularly limited as long as it facilitates the movement of holes, but for example, those containing nitrogen, oxygen, sulfur, etc. Among them, those containing nitrogen are preferable. Examples of the low molecular weight compound containing nitrogen include a low molecular weight compound having an amide group or a pyrrolidone compound. Specific examples of the low molecular compound having an amide group include N-methylformamide, N, N-dimethylformamide, formamide, and γ-butyrolactone. Specific examples of pyrrolidone compounds include N-methyl-2-pyrrolidone, 2-pyrrolidone, and N-vinyl-2-pyrrolidone.

  The content of the low molecular compound having an unpaired electron is not particularly limited as long as the above-described effect can be obtained. Specifically, the content of the low molecular compound in the hole extraction layer is 0.01% by weight to 50%. It can set so that it may exist in the range of weight%, Preferably it exists in the range of 0.1 weight%-30 weight%, More preferably, it exists in the range of 1 weight%-10 weight%. If the content of low molecular weight compounds with unpaired electrons is too large, the nucleophilic reactivity of the low molecular weight compounds with unpaired electrons can cause a chemical reaction with the conductive polymer material, which can modify the conductive polymer material. Because there is sex. Further, if the content of the low molecular compound having unpaired electrons is too small, there is a possibility that the hole transfer path in the hole extraction layer is not sufficiently formed.

In the present invention, it is preferable that the hole extraction layer further contains a resin component as described above. This is because it has the advantages as described above.
The hole extraction layer can be formed by applying a hole extraction layer forming coating solution on the first electrode layer. This coating solution for forming a hole extraction layer is obtained by dispersing a conductive polymer material, a low molecular compound having unpaired electrons, and a resin component in a solvent. Since the dispersibility of the aggregate is good, the leveling property and the film forming property are good. Therefore, it is considered that the adhesion at the interface between the hole extraction layer and the first electrode layer can be improved, and the smoothness and adhesion at the interface between the hole extraction layer and the photoelectric conversion layer can be improved.
Furthermore, it is possible to improve the adhesion between the hole extraction layer and the first electrode layer or the photoelectric conversion layer by using a resin component having high adhesion to the first electrode layer or the photoelectric conversion layer.
As described above, since the smoothness and adhesion at the interface between the hole extraction layer and the first electrode layer or the photoelectric conversion layer are improved, the interface resistance is decreased, so that the short-circuit current value is considered to increase.

Although it does not specifically limit as a resin component used for this invention, It is preferable that it is a thing with high affinity with the said conductive polymer material. Since the resin component is considered to improve the dispersibility of the conductive polymer material in the hole extraction layer, by using a resin component having a high affinity with the conductive polymer material, the conductive polymer material is used. It is because it is thought that the dispersibility of material can be improved effectively.
Specifically, the solubility parameter of the resin component is preferably within the range of 4.0 to 20.0, and more preferably within the range of 6.0 to 13.0.

Furthermore, the resin component preferably has transparency. This is because when the light receiving surface is used as the substrate side, the hole extraction layer needs to be transparent. Specifically, the total light transmittance of the resin component is preferably 85% or more, more preferably 90% or more, and most preferably 92% or more.
The total light transmittance is a value measured using an SM color computer (model number: SM-C) manufactured by Suga Test Instruments Co., Ltd. in the visible light region of a resin component molded into a sheet having a thickness of 100 nm. It is.

The resin component preferably has heat resistance. This is because even when the organic thin film solar cell of the present invention is used in a high temperature environment, it is preferable that the resin component does not change in quality. In addition, a photoelectric conversion layer, a second electrode layer, and the like are formed on the hole extraction layer in the manufacturing process of the organic thin-film solar cell. For example, the hole may be exposed to a high temperature when forming the second electrode. It is preferable that the resin component contained in the extraction layer has heat resistance.
Specifically, the thermal weight loss rate (TGA) at 200 ° C. is preferably 50% or less, more preferably 10% or less.
The thermogravimetric reduction rate is a value measured with a differential thermal analysis (TG-DTA) device at a temperature increase rate of 10 ° C./min.

Further, the resin component preferably has a polymerizable functional group. This is because when the hole extraction layer is formed, if the resin component has a polymerizable functional group, it can be polymerized to form a film, and a high strength hole extraction layer can be obtained.
The polymerizable functional group is not particularly limited as long as it is a polymerizable functional group, and may be a photopolymerizable functional group or a thermally polymerizable functional group. Specific examples include a vinyl group, a (meth) acryl group, an epoxy group, a styryl group, a methacryloyl group, an allyl group, and an oxetanyl group.

  Examples of such a resin component include polyester, emulsified polyester, polyurethane, polyvinyl acetate, poly (meth) acrylate, polyvinylidene chloride, polyamide, and polyimide. Moreover, the copolymer of these monomers and oligomers may be sufficient.

  The content of the resin component is not particularly limited as long as the above-described effects can be obtained. Specifically, the content of the resin component is in the range of 0.01% by weight to 90% by weight in the hole extraction layer. Preferably, it is in the range of 0.1 wt% to 80 wt%, more preferably in the range of 1 wt% to 70 wt%. In general, since many resin components do not have conductivity, if the content of the resin component is too large, the conductivity of the hole extraction layer may be lowered. Further, if the content of the resin component is too small, the dispersibility of the conductive polymer material in the hole extraction layer, the film formability of the hole extraction layer, the hole extraction layer and the photoelectric conversion layer or the first electrode layer This is because there is a possibility that the smoothness, adhesion and the like at the interface of the film may be lowered.

  In the present invention, the hole extraction layer preferably further contains an amphiphilic material. Generally, since the surface energy (surface tension) of a liquid is reduced by containing an amphiphilic material, a hole extraction layer containing a conductive polymer material, a low-molecular compound having an unpaired electron, and a resin component By adding an amphiphilic material to the forming coating solution, the surface energy can be reduced. When such a coating solution for forming a hole extraction layer is applied onto the first electrode layer, the wettability and leveling properties are good, so that the adhesion between the hole extraction layer and the first electrode layer is further improved. It is thought to improve. In addition, since the surface of the hole extraction layer is modified by the amphiphilic material and the wettability with respect to the organic solvent is excellent, the photoelectric conversion layer is formed on the hole extraction layer by wet coating. The conversion layer forming coating solution can be applied uniformly. This is considered to further improve the adhesion between the hole extraction layer and the photoelectric conversion layer.

  Further, in the hole extraction layer forming coating solution, the aggregate of the conductive polymer material is surrounded by the amphiphilic material, so that the dispersibility of the aggregate of the conductive polymer material is improved. Thereby, it is considered that the surface roughness of the hole extraction layer can be effectively improved.

  Therefore, when the hole extraction layer contains an amphiphilic material, the smoothness and adhesion at the interface between the hole extraction layer and the first electrode layer or the photoelectric conversion layer are further improved, and the interface resistance is reduced. It is thought that you can. Therefore, a further increase in the short-circuit current value can be expected.

  In addition, since the dispersibility of the conductive polymer material is improved by the amphiphilic material, it is considered that the formation of the hole transfer path is promoted and the electric conductivity of the hole extraction layer can be effectively increased. .

  Furthermore, the synergistic effect by containing a resin component and an amphiphilic material can be expected. For example, the ideal interface state achieved by the amphiphilic material after application of the coating solution for forming the hole extraction layer is considered to be retained by the presence of the resin component even after drying and solidification.

  As the amphiphilic material used in the present invention, a general surfactant can be used, and among them, a nonionic surfactant or a fluorine-based surfactant is preferable. Examples of the nonionic surfactant include polyoxyethylene alkylphenyl ether, polyoxyethylene alkyl ether, sorbitan fatty acid ester, fatty acid alkylolamide and the like. Examples of the fluorosurfactant include fluoroalkyl carboxylic acid, perfluoroalkyl benzene sulfonic acid, perfluoroalkyl quaternary ammonium, and perfluoroalkyl polyoxyethylene ethanol.

  In the present invention, a fluorosurfactant is preferably used. This is because the fluorosurfactant has a linear fluorinated alkyl group and thus exhibits a higher surface active function than other surfactants. As the fluorosurfactant, the above-mentioned fluoroalkylcarboxylic acid, perfluoroalkylbenzenesulfonic acid, perfluoroalkyl quaternary ammonium, perfluoroalkyl polyoxyethylene ethanol, and the like are preferably used.

  The content of the amphiphilic material is not particularly limited as long as the above-described effect can be obtained. Specifically, the content is in the range of 0.01% by weight to 90% by weight in the hole extraction layer. It can be set to be within the range, preferably within the range of 0.1 wt% to 80 wt%, more preferably within the range of 1 wt% to 70 wt%. As the content of the amphiphilic material increases, the dispersibility of the aggregate of the conductive polymer material is improved because the aggregate of the conductive polymer material is easily surrounded by the amphiphilic material. If the content of the material is too large, the aggregate of the conductive polymer material is excessively surrounded by the amphiphilic material, making it difficult for the adjacent aggregate of the conductive polymer material to approach the hole transport path. This is because there is a possibility of being blocked. On the other hand, if the content of the amphiphilic material is too small, bleeding of the amphiphilic material to the surface of the hole extraction layer is less likely to occur, so the surface modification effect may not be sufficiently obtained. is there.

  The thickness of the hole extraction layer varies depending on the kind of the conductive polymer material, the low molecular compound having unpaired electrons, and the like, and is appropriately adjusted in consideration of the above-described characteristics. Specifically, the thickness of the hole extraction layer is preferably in the range of 0.01 nm to 3000 nm, more preferably in the range of 0.1 nm to 1500 nm, and most preferably in the range of 1 nm to 600 nm. This is because if the film thickness is too thick, the resistance value increases in proportion to the hole transfer path length, and holes may not be sufficiently extracted to the first electrode layer. On the other hand, if the film thickness is too thin, the adhesion between the hole extraction layer and the first electrode layer or the photoelectric conversion layer is lowered, or the photoelectric conversion layer is relatively thin, so that the protrusion on the surface of the first electrode layer is This is because the first electrode layer and the second electrode layer may be in direct contact with each other to cause a short circuit.

  Further, the surface roughness Ra of the hole extraction layer varies depending on the type of the conductive polymer material, the low molecular compound having unpaired electrons, and the like, and is appropriately adjusted in consideration of the above-described characteristics. Specifically, the surface roughness Ra of the hole extraction layer is preferably 50 nm or less, more preferably 30 nm or less, and most preferably 10 nm or less. If the surface roughness is too large, the adhesion between the hole extraction layer and the first electrode layer or the photoelectric conversion layer is reduced, or because the photoelectric conversion layer is relatively thin, This is because there is a possibility that the first electrode layer and the second electrode layer are in direct contact and short-circuited. On the other hand, the smaller the surface roughness, the better the hole extraction efficiency. However, the pursuit of surface smoothness has limitations in the manufacturing process. Therefore, considering the throughput and cost, the lower limit of the surface roughness is about 3 nm. It is.

  The surface roughness Ra is a value measured using an atomic force microscope (Nanopics: trade name, manufactured by Seiko Instruments Inc.) under the conditions of a scan range: 20 μm and a scan speed: 90 sec / frame.

  Furthermore, the surface resistance value of the hole extraction layer is preferably 300Ω / □ or less, more preferably 150Ω / □ or less, and most preferably 50Ω / □ or less. If the surface resistance value is too large, the holes generated in the photoelectric conversion layer cannot be sufficiently transferred to the first electrode layer, or the influence of the barrier due to the smoothness and adhesion of the hole extraction layer becomes too large. This is because the function as an organic thin film solar cell may be impaired. On the other hand, since it is very difficult to select a material capable of forming a hole extraction layer having a small surface resistance value, the lower limit of the surface resistance value is 0.01 Ω / □ or more, preferably 0.1 Ω / □ or more, more preferably 1Ω / □ or more.

  The surface resistance value is a value measured using a surface resistance meter SLT-YKH4101 manufactured by Siltec.

Moreover, it is preferable that a hole extraction layer has transparency. This is because when the light receiving surface is used as the substrate side, the hole extraction layer needs to be transparent. Specifically, the total light transmittance of the hole extraction layer is preferably 85% or more, more preferably 90% or more, and most preferably 92% or more.
The total light transmittance is a value measured using an SM color computer (model number: SM-C) manufactured by Suga Test Instruments Co., Ltd. in the visible light region.

  As a method for forming the hole extraction layer, a wet coating method is usually used. Specifically, the hole extraction layer can be formed by applying a coating solution for forming a hole extraction layer containing a conductive polymer material and a resin component on the first electrode layer.

  At this time, a solvent may be added to the coating solution for forming a hole extraction layer for the purpose of improving film formability. In this case, a coating solution for forming a hole extraction layer is prepared by dispersing a conductive polymer material or a low molecular compound having unpaired electrons in a solvent. As the solvent, a water-soluble solvent is preferably used. In general, a water-insoluble solvent is often used for the photoelectric conversion layer forming coating liquid for forming the photoelectric conversion layer, and such a photoelectric conversion forming coating liquid was applied on the hole extraction layer. In order to prevent the conductive polymer material and low molecular weight compounds having unpaired electrons from eluting from the hole extraction layer, prepare a coating solution for forming the hole extraction layer using a water-soluble solvent. This is because it is preferable.

  Examples of the water-soluble solvent include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, t-butanol, ethylene glycol, propylene glycol, acetone, methyl ethyl ketone, acetonitrile, tetrahydrofuran, dioxane and the like. . These water-soluble solvents may be used alone or in combination of two or more. Among the above, methanol is preferably used.

  The method for applying the coating liquid for forming the hole extraction layer is not particularly limited as long as it can be uniformly formed in a predetermined film thickness. Specifically, die coating method, spin coating method, dip coating method, roll coating method, bead coating method, spray coating method, bar coating method, gravure coating method, ink jet method, screen printing method, offset printing method, etc. Can do.

2. Photoelectric Conversion Layer In the present invention, the photoelectric conversion layer refers to a member that contributes to charge separation of an organic thin film solar cell and has a function of transporting generated electrons and holes toward electrodes in opposite directions. Specifically, when such a photoelectric conversion layer has at least one of a hole transport layer that functions as an electron donor or an electron transport layer that functions as an electron acceptor, the function of both an electron donor and an electron acceptor The case where it consists of an electron hole transport layer which has this can be mentioned. The kind of these photoelectric conversion layers is selected according to the kind of organic thin film solar cell.

  Specifically, as the type of organic thin film solar cell, the photoelectric conversion layer having either one of the electron donating function and the electron accepting function, that is, the electron transport layer or the hole transport layer, A Schottky-type organic thin-film solar cell that is disposed between the first electrode layer and the second electrode layer and uses a Schottky barrier between the electrode and such a photoelectric conversion layer, or an electron accepting and electron donating function As a set, a heterojunction organic thin film solar cell using a pn junction can be used.

Furthermore, in heterojunction organic thin-film solar cells, a bilayer type having a structure in which an electron transport layer having an electron-accepting function and a hole transport layer having an electron-donating function are separately laminated, and electron donation There is a bulk heterojunction type using an electron-hole transport layer in which the functions of the electron accepting function and the electron accepting function are mixed in one layer.
Hereinafter, the photoelectric conversion layer will be described separately for each case where the type of the organic thin film solar cell is a Schottky type or a heterojunction type.

(1) In the case of a Schottky type organic thin film solar cell The photoelectric conversion layer in the present invention is a layer having either an electron donating function or an electron accepting function, that is, either an electron transport layer or a hole transport layer. Thus, a Schottky-type organic thin-film solar cell that obtains a photocurrent using such a Schottky barrier formed at the interface between the photoelectric conversion layer and the electrode can be obtained.

  For example, when the photoelectric conversion layer is a hole transport layer, a Schottky barrier is formed at the interface between the first electrode layer and the second electrode layer with the smaller work function. Charge separation can occur. On the other hand, when the photoelectric conversion layer is an electron transport layer, a photocurrent can be generated at the interface with the electrode having the higher work function of the first electrode layer and the second electrode layer described above.

  Thus, when it is set as a Schottky type organic thin film solar cell, the material which forms a photoelectric converting layer will not be specifically limited if it is a material which has an electron-donating property or an electron-accepting property. Specifically, conductive polymers such as organic single crystals such as pentacene, poly-3-methylthiophene, polyacetylene, polyphenylene and derivatives thereof, polyphenylene vinylene and derivatives thereof, polysilane and derivatives thereof, polyalkylthiophene and derivatives thereof, and the like Derivatives thereof, porphyrin derivatives, phthalocyanine derivatives, merocyanine derivatives, synthetic pigments such as chlorophyll, organometallic polymers, and the like can be mentioned. The photoelectric conversion layer in the Schottky type organic thin film solar cell is formed using either an electron donating material or an electron accepting material. Among these, a material having high charge mobility is preferable.

  Further, the film thickness of the photoelectric conversion layer is preferably in the range of 0.1 nm to 1500 nm, and more preferably in the range of 1 nm to 300 nm. When the film thickness is larger than the above range, the volume resistance of the photoelectric conversion layer may be increased. On the other hand, when the film thickness is smaller than the above range, a short circuit occurs between the first electrode layer and the second electrode layer. This is because it may occur.

  Further, the method for forming such a photoelectric conversion layer is not particularly limited as long as it can be uniformly formed to have a predetermined film thickness. Specifically, die coating method, spin coating method, dip coating method, roll coating method, bead coating method, spray coating method, bar coating method, gravure coating method, ink jet method, screen printing method, offset printing method, etc. Can do. Among these, a spin coating method or a die coating method is preferable. This is because the photoelectric conversion layer can be accurately formed to a film thickness within the above range.

(2) In the case of a heterojunction type organic thin film solar cell As described above, the heterojunction type organic thin film solar cell can be divided into a bilayer type and a bulk heterojunction type. Hereinafter, the photoelectric conversion layer will be described separately for a bilayer type and a bulk heterojunction type.

(I) In the case of a bilayer type organic thin film solar cell The bilayer type organic thin film solar cell includes an electron transport layer having an electron accepting function and a hole transport layer having an electron donating function as a photoelectric conversion layer. It is an organic thin-film solar cell that is separately formed and generates a photocurrent by using a pn junction formed at an interface between them to cause charge separation.

The material for forming the electron transport layer is not particularly limited as long as it has a function as an electron acceptor. Specifically, CN-poly (phenylene-vinylene), MEH-CN-PPV, -CN group or -CF ₃ group-containing polymer, their -CF ₃ substituted polymer, poly (fluorene) derivative, fullerene such as C ₆₀ Examples thereof include materials such as derivatives, carbon nanotubes, perylene derivatives, polycyclic quinones, and quinacridones. Among these, a material having high electron mobility is preferable.

  The material for forming the hole transport layer is not particularly limited as long as it has a function as an electron donor. Specific examples include polyphenylene and derivatives thereof, polyphenylene vinylene and derivatives thereof, polysilane and derivatives thereof, polyalkylthiophene and derivatives thereof, porphyrin derivatives, phthalocyanine derivatives, and organometallic polymers. Among these, a material having a high hole mobility is preferable.

  The film thicknesses of the electron transport layer and the hole transport layer are not particularly limited. Specifically, each film thickness is preferably in the range of 0.1 nm to 1500 nm, and more preferably in the range of 1 nm to 300 nm. . When the film thickness is thicker than the above range, the volume resistance in the electron transport layer and the hole transport layer may be high. On the other hand, when the film thickness is thinner than the above range, the first electrode layer and the second electrode layer This is because a short circuit may occur between the electrode layers.

  Further, the method for forming the electron transport layer or the hole transport layer is not particularly limited as long as it can be uniformly formed in a predetermined film thickness. Specifically, die coating method, spin coating method, dip coating method, roll coating method, bead coating method, spray coating method, bar coating method, gravure coating method, ink jet method, screen printing method, offset printing method, etc. Can do. Among these, a spin coating method or a die coating method is preferable. This is because the photoelectric conversion layer can be formed with high accuracy so as to have a film thickness within the above range.

(Ii) In the case of a bulk heterojunction type organic thin film solar cell The bulk heterojunction type organic thin film solar cell is an electron hole transport layer having both electron accepting and electron donating functions as a photoelectric conversion layer, and electron hole transport. It is an organic thin film solar cell that obtains a photocurrent by causing charge separation using a pn junction formed in a layer.

  The material for forming the electron-hole transport layer is not particularly limited as long as it is generally used in bulk heterojunction organic thin-film solar cells. A material in which both materials of the electron acceptor material are uniformly dispersed can be mentioned. Further, the mixing ratio of both the electron-donating material and the electron-accepting material is appropriately adjusted to an optimal mixing ratio depending on the material to be used.

The electron-accepting material is not particularly limited as long as it has such a function. Specifically, CN-poly (phenylene-vinylene), MEH-CN-PPV, -CN group or -CF ₃ group-containing polymer, their -CF ₃ substituted polymer, poly (fluorene) derivative, C ₆₀ derivative, carbon Examples thereof include materials such as nanotubes, perylene derivatives, polycyclic quinones, and quinacridones. Among these, a material having high electron mobility is preferable.

  The electron donating material is not particularly limited as long as it has such a function. Specific examples include polyphenylene and derivatives thereof, polyphenylene vinylene and derivatives thereof, polysilane and derivatives thereof, polyalkylthiophene and derivatives thereof, porphyrin derivatives, phthalocyanine derivatives, and organometallic polymers. Among these, a material having a high hole mobility is preferable.

  The number of layers of the electron hole transport layer may be one layer or a plurality of layers.

  The film thickness of such an electron hole transport layer is not particularly limited as long as it is a film thickness generally employed in a bulk heterojunction type, and specifically, within a range of 0.2 nm to 3000 nm, Especially, it is preferable that it exists in the range of 1 nm-600 nm. When the film thickness is thicker than the above range, the volume resistance in the electron-hole transport layer may be high. On the other hand, when the film thickness is thinner than the above range, the first electrode layer and the second electrode layer This is because a short circuit may occur.

  In addition, the method for forming the electron hole transport layer is not particularly limited as long as it can be uniformly formed in a predetermined film thickness. Specifically, die coating method, spin coating method, dip coating method, roll coating method, bead coating method, spray coating method, bar coating method, gravure coating method, ink jet method, screen printing method, offset printing method, etc. Can do. Among these, a spin coating method or a die coating method is preferable. This is because the photoelectric conversion layer can be accurately formed to a film thickness within the above range.

3. 1st electrode layer Although it will not specifically limit as long as it has electroconductivity as a material which forms the 1st electrode layer used for this invention, The light irradiation direction and the material which forms the 2nd electrode layer mentioned later It is preferable to select appropriately considering work function and the like.
For example, when the material for forming the second electrode layer is a material having a low work function, the material for forming the first electrode layer is preferably a material having a high work function. Examples of the material having a high work function include Au, Ag, Co, Ni, Pt, C, ITO, SnO ₂ , fluorine-doped SnO ₂ , and ZnO.
Further, when the substrate side is the light receiving surface, the first electrode layer is preferably a transparent electrode. In this case, what is generally used as a transparent electrode can be used. Specifically, In—Zn—O (IZO), In—Sn—O (ITO), ZnO—Al, Zn—Sn—O, and the like can be given.

In the present invention, the total light transmittance of the first electrode layer is preferably 85% or more, more preferably 90% or more, and particularly preferably 92% or more. When the substrate side is a light-receiving surface, the first electrode layer can sufficiently transmit light because the total light transmittance of the first electrode layer is in the above range, and light is efficiently transmitted by the photoelectric conversion layer. It is because it can absorb.
The total light transmittance is a value measured using an SM color computer (model number: SM-C) manufactured by Suga Test Instruments Co., Ltd. in the visible light region.

In the present invention, the sheet resistance of the first electrode layer is preferably 20Ω / □ or less, more preferably 10Ω / □ or less, and particularly preferably 5Ω / □ or less. This is because if the sheet resistance is larger than the above range, the generated charge may not be sufficiently transmitted to the external circuit.
The sheet resistance is measured based on JIS R1637 (low-efficiency test method for fine ceramic thin film: 4-probe method) using a surface resistance meter (Loresta MCP: 4-terminal probe) manufactured by Mitsubishi Chemical Corporation. It is the value.

  The first electrode layer may be a single layer or may be laminated using materials having different work functions. As the film thickness of such a first electrode layer, when it is a single layer, the film thickness is within a range of 0.1 to 500 nm, and among these, 1 nm to 300 nm. It is preferable to be within the range. If the film thickness is smaller than the above range, the sheet resistance of the first electrode layer may become too large, and the generated charge may not be sufficiently transmitted to the external circuit. On the other hand, if the film thickness is larger than the above range, This is because the total light transmittance is lowered and the photoelectric conversion efficiency may be lowered.

  The first electrode layer may be formed on the entire surface of the substrate or may be formed in a pattern.

  As the method for forming the first electrode layer, a generally used method can be used. Specifically, a PVD method such as a vacuum deposition method, a sputtering method, or an ion plating method, or a dry method such as a CVD method. Examples thereof include a coating method and a wet coating method in which a coating solution containing ITO fine particles is applied. The patterning method for forming the first electrode layer in a pattern is not particularly limited as long as it can accurately form the first electrode layer in a desired pattern. Lithographic methods and the like can be mentioned.

4). Second electrode layer The second electrode layer used in the present invention is an electrode facing the first electrode layer. The material for forming the second electrode layer is not particularly limited as long as it has conductivity, but it is appropriately selected in consideration of the irradiation direction of light, the work function of the material for forming the first electrode layer, and the like. It is preferable.
For example, when the substrate side is a light receiving surface, the first electrode layer is a transparent electrode. In such a case, the second electrode layer may not be transparent.
In the case where the first electrode layer is formed using a material having a high work function, the second electrode layer is preferably formed using a material having a low work function. Specific examples of the material having a low work function include Li, In, Al, Ca, Mg, Sm, Tb, Yb, Zr, and LiF.

  The second electrode layer may be a single layer or may be laminated using materials having different work functions.

  The film thickness of the second electrode layer is a single layer, and when it is composed of a plurality of layers, the total film thickness of each layer is within a range of 0.1 nm to 500 nm, particularly 1 nm. It is preferable to be within a range of ˜300 nm. If the film thickness is smaller than the above range, the sheet resistance of the second electrode layer may become too large, and the generated charge may not be sufficiently transmitted to the external circuit. On the other hand, if the film thickness is larger than the above range, This is because the total light transmittance is lowered and the photoelectric conversion efficiency may be lowered.

  Further, the second electrode layer may be formed on the entire surface of the photoelectric conversion layer or may be formed in a pattern.

  As a method for forming such a second electrode layer, a generally used method can be used, for example, a PVD method such as a vacuum deposition method, a sputtering method, an ion plating method, or a dry coating method such as a CVD method. And a wet coating method in which a metal paste containing a metal colloid such as Ag is used. The patterning method for forming the second electrode layer in a pattern is not particularly limited as long as the second electrode layer can be accurately formed in a desired pattern. Lithographic methods and the like can be mentioned.

5. Substrate The substrate used in the present invention is not particularly limited, whether it is transparent or opaque. For example, when the substrate side is a light receiving surface, it is a transparent substrate. Is preferred. The transparent substrate is not particularly limited, and for example, a non-flexible transparent rigid material such as quartz glass, Pyrex (registered trademark), synthetic quartz plate, or a transparent resin film, an optical resin plate, etc. The transparent flexible material which has flexibility can be mentioned.

  In the present invention, among the above, the substrate is preferably a flexible material such as a transparent resin film. Transparent resin films are excellent in processability, and are useful in the realization of organic thin-film solar cells that reduce manufacturing costs, reduce weight, and are difficult to break, and expand the applicability to various applications such as application to curved surfaces. is there.

6). Electron Extraction Layer In the bilayer organic thin-film solar cell of the present invention, an electron extraction layer 6 may be formed between the photoelectric conversion layer 4 and the second electrode layer 5 as shown in FIG.

  The electron extraction layer is a layer provided so that electrons can be easily extracted from the photoelectric conversion layer to the second electrode layer. Thereby, since the electron extraction efficiency from the photoelectric conversion layer to the second electrode layer is increased, the photoelectric conversion efficiency can be improved.

  A material used for such an electron extraction layer is not particularly limited as long as it is a material that stabilizes extraction of electrons from the photoelectric conversion layer to the second electrode layer. Specifically, conductive organic compounds such as doped polyaniline, polyphenylene vinylene, polythiophene, polypyrrole, polyparaphenylene, polyacetylene, triphenyldiamine (TPD), or electron donation such as tetrathiofulvalene, tetramethylphenylenediamine, etc. An organic material that forms a charge transfer complex composed of an organic compound and an electron-accepting compound such as tetracyanoquinodimethane and tetracyanoethylene. Moreover, the metal dope layer with an alkali metal or alkaline-earth metal is mentioned. Suitable materials include bathocuproin (BCP) or bathophenantrone (Bphen) and metal doped layers such as Li, Cs, Ba, Sr.

7). Others The organic thin film solar cell of the present invention may have constituent members to be described later as needed in addition to the constituent members described above.

(1) Protective sheet In this invention, the protective sheet may be formed on the 2nd electrode layer. A protective sheet is a layer provided in order to protect the organic thin-film solar cell of this invention from the external environment.

  Materials used for the protective sheet include a metal plate or metal foil such as aluminum, a fluorine resin sheet, a cyclic polyolefin resin sheet, a polycarbonate resin sheet, a poly (meth) acrylic resin sheet, a polyamide resin sheet, and a polyester resin. Examples thereof include a resin sheet or a composite sheet obtained by laminating and laminating a weather resistant film and a barrier film.

  The thickness of the protective sheet is preferably in the range of 20 μm to 500 μm, more preferably in the range of 50 μm to 200 μm.

  Further, the protective sheet may have a barrier property as described in the column of a barrier layer described later.

  Furthermore, the design properties can be imparted to the protective sheet by coloring or the like. At this time, it may be colored by kneading the pigment into the protective sheet or the like, for example, by laminating a colored layer such as a blue hard coat layer.

(2) Filler layer In the present invention, a filler layer may be formed between the second electrode layer and the protective sheet. A filler layer is a layer provided in order to adhere the back surface side of an organic thin film solar cell, ie, a 2nd electrode layer, and the said protective sheet, and to seal an organic thin film solar cell.

  As such a filler layer, what is generally used as a filler layer of a solar cell should just be mentioned, for example, ethylene-vinyl acetate copolymer resin is mentioned.

  Moreover, it is preferable that the thickness of the said filler layer exists in the range of 50 micrometers-2000 micrometers, and it is more preferable that it exists in the range of 200 micrometers-800 micrometers. This is because when the thickness is less than the above range, the strength is reduced, and conversely, when the thickness is greater than the above range, cracks and the like are likely to occur.

(3) Barrier layer In the present invention, a barrier layer may be formed on the surface of the substrate or the surface of the protective sheet. Moreover, when the said board | substrate or the said protective sheet consists of multiple layers, you may provide a barrier layer between each layer. The barrier layer used in the present invention is a transparent layer, and is a layer provided to prevent the entry of oxygen and water vapor from the outside and protect the organic thin film solar cell of the present invention.

The barrier layer used in the present invention has an oxygen permeability of 5 cc / m ² / day or less, and preferably 0.1 cc / m ² / day or less. Further, the water vapor transmission rate is 5 g / m ² / day or less, preferably 0.01 g / m ² / day or less.
The oxygen permeability is a value measured under the conditions of 23 ° C. and 90% Rh using an oxygen gas permeability measuring device (manufactured by MOCON, OX-TRAN 2/20). The water vapor transmission rate is a value measured using a water vapor transmission rate measurement device (manufactured by MOCON, PERMATRAN-W 3/31) under conditions of 37.8 ° C. and 100% Rh.

  Such a barrier layer is not particularly limited as long as it has the above-described barrier properties, but it is preferable to have a vapor deposition layer formed by a vapor deposition method because of its high barrier properties. .

  The vapor deposition layer is not particularly limited as long as it is a layer formed by a vapor deposition method, and may be a CVD method or a PVD method. When the vapor deposition layer is formed by a CVD method such as a plasma CVD method, it is possible to form a dense and highly barrier layer. In the present invention, however, from the viewpoint of manufacturing efficiency and cost, etc. The PVD method is preferred. Examples of the PVD method used in the present invention include a vacuum vapor deposition method, a sputtering method, and an ion plating method. Among these, the vacuum vapor deposition method is preferable from the standpoint of barrier properties. Specific examples of the vacuum deposition method used in the present invention include a vacuum deposition method using an electron beam (EB) heating method, a vacuum deposition method using a high frequency dielectric heating method, and the like.

Further, the material for the vapor deposition layer is preferably a metal or an inorganic oxide, Ti, Al, Mg, Zr, silicon oxide, aluminum oxide, silicon oxynitride, aluminum oxynitride, magnesium oxide, zinc oxide, indium oxide, oxide Tin, yttrium oxide, B ₂ O ₃ , CaO and the like can be mentioned, and among these, silicon oxide is preferable. This is because the layer made of silicon oxide has high barrier properties and transparency.

  Further, the thickness of the vapor deposition layer in the present invention is appropriately selected depending on the type and configuration of the material used, and is suitably selected, but is preferably in the range of 5 nm to 1000 nm, particularly 10 nm to 500 nm. This is because if the thickness of the vapor deposition layer is thinner than the above range, it may be difficult to obtain a uniform layer and the barrier property may not be obtained. In addition, when the thickness of the vapor deposition layer is larger than the above range, the barrier property may be significantly impaired after the film formation due to a crack in the vapor deposition layer due to external factors such as pulling. In addition, it takes time to form and the productivity is also lowered.

(4) Layer structure In the present invention, there is no particular limitation as long as the hole extraction layer and the photoelectric conversion layer are arranged in this order between the first electrode layer and the second electrode layer. For example, as described above, the photoelectric conversion layer may be a single layer or a plurality of layers, and when the photoelectric conversion layer is a plurality of layers, a separate electrode layer may be provided between each layer.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has any configuration that has substantially the same configuration as the technical idea described in the claims of the present invention and that exhibits the same effects. Are included in the technical scope.

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples.
[Example 1]
(Formation of first electrode layer)
A SiO ₂ thin film is formed on the surface of a polyethylene naphthalate (PEN) film substrate (thickness: 125 μm) by the PVD method, and an ITO film (film thickness: 150 nm, sheet resistance: 20Ω / sheet) as a transparent electrode on the upper surface of the SiO ₂ thin film. □) is formed by ion plating (power: 3.7 kW, oxygen partial pressure: 73%, film forming pressure: 0.3 Pa, film forming rate: 150 nm / min, substrate temperature: 20 ° C.), and then etching is performed. Was patterned. Next, the substrate on which the ITO pattern was formed was cleaned using acetone, a substrate cleaning solution, and IPA.

(Formation of hole extraction layer)
A conductive polymer paste was prepared as a coating liquid for forming a hole extraction layer. Poly (3,4) -ethylenedioxythiophene / polystyrene sulfonate (PEDOT / PSS) 2 wt% aqueous dispersion, 25 wt% aqueous dispersion of polyester resin, N-methylformamide, and fluorosurfactant (Fluoroalkylcarboxylic acid) was added at a weight ratio of 90: 5: 4: 1, and the mixture was stirred with a stirrer for 50 minutes to obtain the intended conductive polymer paste.
Next, a conductive polymer paste was formed on the substrate on which the ITO pattern was formed by spin coating, and dried at 150 ° C. for 30 minutes to form a hole extraction layer (film thickness: 100 nm).

(Formation of photoelectric conversion layer)
A 0.3 wt% chloroform solution of polythiophene (P3HT: poly-3-hexylthiophene-2,5-diyl (resiregular)) and fullerene (PCBM: 1- (3-methoxycarbonyl) propyl-1-phenyl (6,6 ) -C ₆₀ ) 0.1 wt% chloroform solution was mixed at a weight ratio of 3: 1, and this mixed solution was filtered through a filter paper of φ0.2 μm to prepare a photoelectric conversion layer forming coating solution.
This coating film for forming a photoelectric conversion layer was formed on the hole extraction layer by spin coating, and dried at 110 ° C. for 10 minutes to form a photoelectric conversion layer (film thickness: 30 nm).

(Formation of second electrode layer)
Next, a Ca thin film (film thickness: 100 nm) and an Al thin film (film thickness: 500 nm) were sequentially formed on the photoelectric conversion layer by a vapor deposition method to obtain a metal electrode.

(Production of organic thin film solar cells)
Finally, sealing was performed from above the metal electrode with a sealing glass material to produce a bulk heterojunction type organic thin film solar cell.

[Example 2]
In Example 1, when forming a hole extraction layer, an organic thin film solar cell was produced in the same manner as in Example 1 except that a conductive polymer paste was prepared using only N-methylformamide as an additive component. did.

[Comparative example]
In Example 1, except that a conductive polymer paste was prepared without using a polyester resin, N-methylformamide, and a fluorosurfactant as additive components when forming the hole extraction layer. In the same manner, an organic thin film solar cell was produced.

[Evaluation]
Regarding the solar cell characteristics, AM1.5 and simulated sunlight (100 mW / cm ² ) were used as irradiation light sources, and current-voltage characteristics were evaluated by applying voltage with a source measure unit (HP4100, manufactured by HP). The organic thin film solar cell of the comparative example had a photoelectric conversion efficiency of 0.6% and a short-circuit current density of 2.0 mA / cm ² , whereas the organic thin film solar cell of Example 1 had a photoelectric conversion efficiency of 2.0. %, short-circuit current density of 7.0 mA / cm ^2, 1.0% photoelectric conversion efficiency in the organic thin-film solar battery of example 2, the short-circuit current density was improved 3.5mA / cm ^2, and the performance of the solar cell .

It is a schematic sectional drawing which shows an example of the organic thin film solar cell of this invention. It is explanatory drawing for demonstrating a hole extraction layer. It is a schematic sectional drawing which shows the other example of the organic thin film solar cell of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Board | substrate 2 ... 1st electrode layer 3 ... Hole extraction layer 4 ... Photoelectric conversion layer 5 ... 2nd electrode layer 6 ... Electron extraction layer 10 ... Organic thin film solar cell 11 ... Aggregate of a conductive polymer material 12 ... Non Low-molecular compound with counter-electron 13 ... Hole transport path 14 ... Resin component

Claims (7)

A substrate, a first electrode layer formed on the substrate, a hole extraction layer formed on the first electrode layer, a photoelectric conversion layer formed on the hole extraction layer, and the photoelectric conversion An organic thin film solar cell having a second electrode layer formed on the layer,
The organic thin-film solar cell, wherein the hole extraction layer contains a conductive polymer material and a low molecular compound having unpaired electrons.   The organic thin film solar cell according to claim 1, wherein the low molecular compound having unpaired electrons contains nitrogen.   The organic thin-film solar cell according to claim 1, wherein the hole extraction layer contains a resin component.   The organic thin film solar cell according to claim 3, wherein the resin component has high affinity with the conductive polymer material.   The organic thin-film solar cell according to any one of claims 1 to 4, wherein the hole extraction layer contains an amphiphilic material.   6. The organic thin film solar cell according to claim 5, wherein the amphiphilic material is a nonionic surfactant or a fluorine-based surfactant. The organic thin-film solar cell according to any one of claims 1 to 6, wherein an electron extraction layer is formed between the photoelectric conversion layer and the second electrode layer.

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