JP5648380B2 - Photoelectric conversion element, method for manufacturing photoelectric conversion element, and solar cell - Google Patents

Description

  The present invention relates to a photoelectric conversion element material, a photoelectric conversion element using the photoelectric conversion element material, and a solar cell using the photoelectric conversion element.

  The organic thin film solar cell has an element structure in which an organic p-type semiconductor such as benzoporphyrin, phthalocyanine, or a conjugated polymer and a thin film made of an organic n-type semiconductor such as perylene diimide or fullerene derivative are sandwiched between electrodes. Although its practical application has been studied, at present, the photoelectric conversion efficiency is still as low as 4 to 6%, and further improvement in efficiency is an issue. On the other hand, as a means for solving the photoelectric conversion efficiency improvement of the organic thin film solar cell, for example, Patent Document 1 proposes to use an aryl group or heteroaryl group-substituted phosphine oxide compound as an electron transport material for the organic layer.

JP 2006-073583 A

  However, according to the study by the inventors of the present application, even if the phosphine oxide compound described in Patent Document 1 is applied as a photoelectric conversion element material such as an electrode buffer material of a solar cell, it is still unsatisfactory in terms of photoelectric conversion efficiency. It turned out to be sufficient. Therefore, the present invention has been made in view of the above-described conventional situation, and as a buffer material for a solar cell, photoelectric conversion capable of improving the photoelectric conversion efficiency while maintaining the interaction and mobility with the electrode. An object is to provide an element material, a photoelectric conversion element using the photoelectric conversion element material, and a solar cell using the photoelectric conversion element.

As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that a phosphine oxide or phosphine sulfide compound substituted with an aromatic group having a fluorine atom is effective in improving the performance, and to complete the present invention. It came. That is, the gist of the present invention is as follows.
[1] The photoelectric conversion element having at least an active layer and an electrode buffer layer between a pair of electrodes, the electrode buffer material made of the electrode buffer layer is phosphine oxide or phosphine sulfide compound represented by the following general formula (1) Containing a photoelectric conversion element .

[In the formula (1), Ar ¹ represents an acenaphthylene ring, phenanthrene ring, anthracene ring, triphenylene ring, pyrene ring, chrysene ring, perylene ring, dibenzofuran ring, xanthene ring, carbazole ring, quinoline ring, isoquinoline ring, acridine ring, Represents a nanthridine ring, a phenanthroline ring, a quinoxaline ring, a dibenzothiophene ring, or a phenoxazine ring , Ar ² represents a monocyclic aromatic group, A represents a fluorine atom or a perfluoroalkyl group, and X represents an oxygen atom or Represents a sulfur atom. m is an integer of 1 to 3, n is an integer of 1 to 5, and p is an integer of 1 or more. However, when m is 3, p is 1. ]
[2] A solar cell comprising the photoelectric conversion element according to [1].
[3] The method for producing a photoelectric conversion element according to [1], wherein the buffer layer is formed by a wet coating method.

  The present invention relates to a photoelectric conversion element material capable of improving the photoelectric conversion efficiency while maintaining the interaction and mobility with an electrode as an electrode buffer material of a solar cell, and a photoelectric conversion element using the photoelectric conversion element material. A conversion element and a solar cell using the photoelectric conversion element can be provided.

It is sectional drawing which shows typically the structure of the photoelectric conversion element as one Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described in detail.
[Phosphine oxide or phosphine sulfide compound]
The photoelectric conversion element material of the present invention comprises a phosphine oxide or phosphine sulfide compound represented by the following general formula (1).

[In the formula (1), Ar ¹ and Ar ² represent a group containing one or more aromatic groups, A represents a fluorine atom or a perfluoroalkyl group, and X represents an oxygen atom or a sulfur atom. m is an integer of 1 to 3, n is an integer of 1 to 5, and p is an integer of 1 or more. However, when m is 3, p is 1. ]
In the general formula (1), Ar ¹ is a group containing one or more aromatic groups. Specific examples of the aromatic group include a benzene ring, naphthalene ring, azulene ring, biphenylene ring, acenaphthylene ring, fluorene ring, phenanthrene ring, anthracene ring, fluoranthene ring, triphenylene ring, pyrene ring, chrysene ring, naphthacene ring. Aromatic hydrocarbon groups such as monovalent or divalent groups of aromatic hydrocarbon rings such as perylene ring and pentacene ring, heterocycles of one atom of oxygen such as furan ring, benzofuran ring, dibenzofuran ring and xanthene ring, pyrrole Ring, indole ring, indolizine ring, carbazole ring, pyridine ring, quinoline ring, isoquinoline ring, acridine ring, phenanthridine ring, phenanthroline ring, etc., heterocycles with one nitrogen atom, imidazole ring, pyrazole ring, pyrimidine ring, pyrazine Rings, heterocycles with two nitrogen atoms such as quinoxaline rings, tria 3-nitrogen heterocycles such as thiophene rings, thiophene rings, benzothiophene rings, dibenzothiophene rings, etc., sulfur 1-atom heterocycles, thianthrene rings, etc., sulfur 2-atom heterocycles, oxazole rings, oxadiazole rings, phenoxy Aromatic heterocycles such as oxygen and nitrogen heterocycles such as sazine rings, sulfur and nitrogen heterocycles such as thiazole rings, thiadiazole rings and phenothiazine rings, and sulfur and oxygen heterocycles such as phenoxathiine Examples thereof include aromatic heterocyclic groups such as a monovalent group or a divalent group of a ring, and Ar ¹ is an aromatic hydrocarbon group or an aromatic heterocyclic group alone, or these are directly connected to each other, Alternatively, it may be linked via an alkylene group, a silylene group, an amino group, an oxygen atom, a sulfur atom or the like.

In the present invention, Ar ¹ is a monovalent aromatic hydrocarbon ring such as a benzene ring, naphthalene ring, acenaphthylene ring, fluorene ring, phenanthrene ring, anthracene ring, fluoranthene ring, triphenylene ring, pyrene ring, chrysene ring or perylene ring. Aromatic hydrocarbon group such as a divalent group or divalent group, dibenzofuran ring, xanthene ring, carbazole ring, pyridine ring, quinoline ring, isoquinoline ring, acridine ring, phenanthridine ring, phenanthroline ring, imidazole ring, pyrazole ring, pyrimidine ring Preferred are aromatic heterocyclic groups such as monovalent or divalent aromatic heterocycles such as pyrazine ring, quinoxaline ring, dibenzothiophene ring, phenoxazine ring, etc., benzene ring, naphthalene ring, fluorene ring, phenanthrene ring , Triphenylene ring, pyrene ring, chrysene Aromatic hydrocarbon groups such as monovalent or divalent groups of aromatic hydrocarbon rings such as dibenzofuran ring, carbazole ring, pyridine ring, quinoline ring, isoquinoline ring, acridine ring, phenanthridine ring, phenanthroline ring, imidazole An aromatic heterocyclic group such as a monovalent group or a bivalent group of an aromatic heterocyclic ring such as a ring, a quinoxaline ring or a dibenzothiophene ring is more preferable.

The aromatic hydrocarbon group such as monovalent or divalent group of the aromatic hydrocarbon ring as Ar ¹ and the aromatic heterocyclic group such as monovalent or divalent group of the aromatic heterocyclic ring are as follows: , May have a substituent. Examples of the substituent include halogen atoms, cyano groups, carbonyl groups, acetyl groups, sulfonyl groups, alkyl groups, perfluoroalkyl groups, alkenyl groups, alkynyl groups, alkoxy groups, aromatic hydrocarbon groups, aromatic heterocyclic groups, and the like. Is mentioned. These may be connected with adjacent substituents to form a ring.

  Here, the aromatic hydrocarbon group as a substituent is preferably one having 6 to 20 carbon atoms, and is not limited to a monocyclic group, and may be a condensed polycyclic hydrocarbon group or a ring assembly hydrocarbon group. May be. Specific examples include monocyclic groups such as phenyl groups, naphthyl groups, phenanthryl groups, biphenylenyl groups, anthryl groups, pyrenyl groups, fluorenyl groups, perylenyl groups and other condensed polycyclic hydrocarbon groups, biphenyl groups, terphenyl groups, etc. Ring aggregate hydrocarbon groups, and the like. Among these, a phenyl group and a naphthyl group are preferable.

  In addition, the aromatic heterocyclic group as a substituent is preferably a group having 5 to 20 carbon atoms, and specific examples include a furyl group, a dibenzofuryl group, an imidazolyl group, a pyrazolyl group, a carbazolyl group, a pyridyl group, and a pyrimidinyl group. , Pyrazinyl group, thienyl group, benzothienyl group, dibenzothienyl group, oxazolyl group, oxadiazolyl group, thiazolyl group, etc., among them dibenzofuryl group, pyridyl group, thienyl group, benzothienyl group, dibenzothienyl group Is preferred.

In the general formula (1), Ar ² is a group containing one or more aromatic groups. Specific examples of the aromatic group include a benzene ring, naphthalene ring, azulene ring, biphenylene ring, acenaphthylene ring, fluorene ring, phenanthrene ring, anthracene ring, fluoracene ring, triphenylene ring, pyrene ring, chrysene ring, naphthacene ring. , Aromatic hydrocarbon groups such as monovalent aromatic hydrocarbon rings such as perylene ring and pentacene ring, heterocycles with one oxygen atom such as furan ring, benzofuran ring, dibenzofuran ring, xanthene ring, pyrrole ring, indole ring , An indolizine ring, a carbazole ring, a pyridine ring, a quinoline ring, an isoquinoline ring, an acridine ring, a phenanthridine ring, a phenanthroline ring, and the like, a nitro ring, an imidazole ring, a pyrazole ring, a pyrimidine ring, a pyrazine ring, a quinoxaline ring 2-nitrogen heterocycle such as thiophene ring, benzo 1-sulfur heterocycle such as offene ring, dibenzothiophene ring, 2-sulfur heterocycle such as thianthrene ring, heterocycle of oxygen and nitrogen atoms such as oxazole ring, oxadiazole ring, phenoxazine ring, thiazole ring Aromatic heterocyclic groups such as monovalent groups of aromatic heterocyclic rings such as sulfur rings and nitrogen atoms such as thiadiazole rings and phenothiazine rings, and sulfur and oxygen atoms such as phenoxathiin Ar ² is an aromatic hydrocarbon group or an aromatic heterocyclic group alone, or a plurality of these are directly connected, or via an alkylene group, a silylene group, an amino group, an oxygen atom, a sulfur atom, or the like. It may be connected.

In the present invention, Ar ² is a monovalent aromatic hydrocarbon ring such as a benzene ring, naphthalene ring, acenaphthylene ring, fluorene ring, phenanthrene ring, anthracene ring, fluoranthene ring, triphenylene ring, pyrene ring, chrysene ring or perylene ring. Aromatic hydrocarbon group such as a group, dibenzofuran ring, xanthene ring, carbazole ring, pyridine ring, quinoline ring, isoquinoline ring, acridine ring, phenanthridine ring, phenanthroline ring, imidazole ring, pyrazole ring, pyrimidine ring, pyrazine ring, Aromatic heterocyclic groups such as monovalent aromatic heterocyclic rings such as quinoxaline ring, dibenzothiophene ring and phenoxazine ring are preferred, such as benzene ring, naphthalene ring, fluorene ring, phenanthrene ring, triphenylene ring, pyrene ring, chrysene Of aromatic hydrocarbon rings such as rings Aromatic hydrocarbon groups such as valent groups, dibenzofuran rings, carbazole rings, pyridine rings, quinoline rings, isoquinoline rings, acridine rings, phenanthridine rings, phenanthroline rings, imidazole rings, quinoxaline rings, dibenzothiophene rings, etc. An aromatic heterocyclic group such as a monovalent group of a ring is more preferable, the aromatic hydrocarbon ring and the aromatic heterocyclic ring are particularly preferably a monovalent group of a monocyclic aromatic ring, and a benzene ring A monovalent group, that is, a phenyl group is most preferred.

In the general formula (1), Ar ² has a substituent A which is a fluorine atom or a perfluoroalkyl group. Specific examples of the perfluoroalkyl group include a trifluoromethyl group and a pentafluoro group. Examples thereof include an ethyl group, and a trifluoromethyl group is particularly preferable.
By introducing fluorine atoms, it exhibits a number of unique properties such as increased oil solubility, mimic effect, blocking effect, thermal stability, chemical stability and even low surface properties. Such a characteristic of fluorine is mainly a unique property of a fluorine atom, that is, a steric hydrogen followed by a small atom (Van der Waals radius (H: 1.2 Å; F: 1.35 Å)). The bond strength with carbon (C—F: 116 kcal / mol) is stronger than halogen atoms other than hydrogen and fluorine atoms (C—H: 99.5 kcal / mol; C—Cl: 78 kcal / mol), The bond distance of carbon-fluorine bond (CF = 1.32１．３) is shorter than the carbon-chlorine bond distance (C-Cl: 1.77Å), which is caused by properties such as inflexibility and low polarizability. It is.

  Thermal stability and scientific stability provide excellent storage stability as a photoelectric conversion material, and increased oil solubility makes it possible to handle not only vapor deposition but also coating processes. In addition, fluorinated alkyl has the property that it has a low surface energy and is likely to be localized near the surface of the thin film. By utilizing this phenomenon, a compound into which fluorine has been introduced is formed on the surface in a self-organized manner, and the photoelectrical described later. It can also be applied to a buffer layer in a conversion element.

Further, since fluorine interacts with π electrons and hydrogen atoms, charge transfer is likely to occur due to intermolecular interaction in the film, and an improvement in the performance of the photoelectric conversion element can be expected.
An aromatic hydrocarbon group such as a monovalent group of the aromatic hydrocarbon ring as Ar ² and an aromatic heterocyclic group such as a monovalent group of the aromatic heterocyclic ring are further substituted in addition to the above A You may have. Examples of the substituent include a cyano group, a carbonyl group, an acetyl group, a sulfonyl group, an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, and an aryloxy group.

In the general formula (1), m which is an integer of 1 to 3 is preferably 1 or 2, and n which is an integer of 1 to 5 is preferably 1 to 3, Further, p, which is an integer of 1 or more, is preferably 6 or less, particularly preferably 1 to 3.
In the phosphine oxide or phosphine sulfide compound represented by the above general formula (1), when m = 2 and p ≧ 2, Ar ¹ becomes a divalent or higher valent linking group. Specific examples in that case are shown below. However, it is not limited to these.

Specific examples of the phosphine oxide or phosphine sulfide compound represented by the above general formula (1) are shown below, but are not limited thereto.
Compound when m = 1 and p = 1

  Compound when m = 2 and p = 1

  Compound when m = 3 and p = 1

  Compound when m = 2 and p = 2

  Compound when m = 2 and p = 3

[Method for producing phosphine oxide or phosphine sulfide compound]
There is no limitation in particular as a manufacturing method of the phosphine compound used as the raw material of the phosphine oxide or phosphine sulfide compound represented by the said General formula (1). For example, it can be obtained by the following scheme described in Synthesis 2006, 2,354.

The compound of the general formula 1 can be obtained by reacting the obtained compound with an oxidizing agent such as hydrogen peroxide.
In the above scheme, the phosphine oxide compound represented by Ar ² = Ar ³ is represented by the following scheme when Ar ¹ = phenyl group is described as an example.

  That is, aryl dihalide is reacted with a metal reagent such as butyl lithium or magnesium to synthesize a metal compound: M-Ar, and then reacted with phosphine chloride (1-1) in an organic solvent (1 -2) can be obtained. As the organic solvent at that time, diethyl ether, tetrahydrofuran (THF) or the like is preferable. The reaction temperature varies depending on the metal reagent used, but is preferably -78 ° C to 110 ° C. Next, the compound represented by (1-3) can be obtained by reacting the compound represented by (1-2) with hydrogen peroxide in an organic solvent. As the organic solvent at that time, acetone, tetrahydrofuran (THF) and the like are preferable. The reaction temperature varies depending on the organic solvent used, but is preferably 0 ° C to 110 ° C.

[Photoelectric conversion element materials]
The photoelectric conversion element material of the present invention is composed of the phosphine oxide or the phosphine sulfide compound, and the photoelectric conversion element material is used as an electrode buffer material, a semiconductor material, and an additive of the photoelectric conversion element, and is used as an electrode buffer material. It is preferred that
In using the photoelectric conversion element material of the present invention as an electrode buffer material, for example, any one of the phosphine oxides or phosphine sulfide compounds may be used alone, or two or more kinds may be used in combination. Moreover, although you may comprise only from the said phosphine oxide or a phosphine sulfide compound, it is good also as a structure which added the other high molecular compound, the monomer, various additives, etc., for example.

As a photoelectric conversion element material, the glass transition temperature is preferably 80 ° C. or higher, more preferably 110 ° C. or higher, and further preferably 120 ° C. or higher in order to eliminate the problem of crystallization during the annealing treatment. The temperature is preferably 130 ° C. or higher. Further, in order to eliminate the problem that the current is difficult to extract and the photoelectric conversion efficiency is reduced, the electron mobility is preferably 10 ⁻⁸ cm ² / Vs or more, and preferably 10 ⁻⁷ cm ² / Vs or more. More preferably, it is 10 ⁻⁶ cm ² / Vs or more.

[Photoelectric conversion element]
In the present invention, the photoelectric conversion element is a photoelectric conversion element having at least an active layer and a buffer layer between a pair of electrodes, the buffer layer being an electrode buffer layer adjacent to at least one electrode, and the electrode buffer layer is It contains a photoelectric conversion element material. The photoelectric conversion element material of the present invention is a compound capable of coordinating to a metal, and by containing such a compound in a buffer layer adjacent to an electrode, the metal can enter the active layer and prevent the active material from being decomposed. The effect of doing can be expressed.

  FIG. 1 is a sectional view showing a layer structure of a general photoelectric conversion element used in an organic thin film solar cell. In FIG. 1, a photoelectric conversion element includes an electrode buffer layer 102, a p-type semiconductor layer 103, a mixed layer 104 of a p-type semiconductor and an n-type semiconductor, and an n-type on a substrate 100 on which a transparent electrode 101 is formed. It has a layer structure in which an active layer having a semiconductor layer 105, an electrode buffer layer 106, and a counter electrode 107 are sequentially formed.

<Board>
The photoelectric conversion element according to the present invention usually has a substrate serving as a support. That is, an electrode, an active layer, and a buffer layer are formed on the substrate. Conventionally known materials can be used as the substrate material in the present invention. Preferred examples of the substrate material include inorganic materials such as quartz, glass, sapphire, and titania; polyethylene terephthalate, polyethylene naphthalate, polyether sulfone, polyimide, nylon, polystyrene, polyvinyl alcohol, ethylene vinyl alcohol copolymer, Organic materials such as fluorine resin, polyolefins such as polyvinyl chloride and polyethylene, cellulose, polyvinylidene chloride, aramid, polyphenylene sulfide, polyurethane, polycarbonate, polyarylate, polynorbornene, epoxy resin; paper materials such as paper and synthetic paper; stainless steel In addition, composite materials such as those obtained by coating or laminating the surface to impart insulating properties to metals such as titanium and aluminum can be used. Examples of the glass include soda glass, blue plate glass, and alkali-free glass.

Among them, alkali-free glass is preferable because it is better that there are fewer ions eluted from the glass.
There is no restriction | limiting in the thickness of a board | substrate, For example, things, such as plate shape, a film form, and a sheet form, can be used. However, it is usually 5 μm or more, preferably 20 μm or more, and usually 20 mm or less, preferably 10 mm or less. If the substrate is too thin, the strength of the photoelectric conversion element tends to be insufficient. If the substrate is too thick, the cost tends to be high or the weight tends to be too heavy. Also, when the substrate is glass, if it is too thin, the mechanical strength decreases and it is easy to break, so it is preferably 0.01 mm or more, more preferably 0.1 mm or more, and if it is too thick, the weight becomes heavy. Therefore, it is preferably 10 mm or less, more preferably 5 mm or less.

<Electrode>
In the photoelectric conversion element according to the present invention, a conventionally known electrode can be used as the electrode, and any one of the pair of electrodes may be translucent, and both may be translucent. . Here, having translucency means that the light transmittance of sunlight is 40% or more, and that the light transmittance is 70% or more, allows light to reach the active layer through the transparent electrode. It is preferable to make it. The light transmittance can be measured with a normal spectrophotometer.

The material used for the transparent electrode is not particularly limited as long as it has conductivity. For example, nickel oxide, tin oxide, indium oxide, indium tin oxide (ITO), indium-zirconium oxide ( IZO), conductive metal oxides such as titanium oxide and zinc oxide, metals such as gold, platinum, silver and chromium and alloys thereof, PEDOT / PSS in which polythiophene derivatives are doped with polystyrene sulfonic acid, polypyrrole, polyaniline, etc. Examples thereof include conductive polymers doped with iodine or the like. These electrode materials may be used alone, or a plurality of materials may be mixed and used. Especially, it is preferable to use transparent electrodes, such as oxides, such as ITO, a tin oxide, zinc oxide, and IZO, for the electrode in the position which permeate | transmits light. Alternatively, a material having a high work function such as ITO, tin oxide, zinc oxide, gold, cobalt, nickel, or platinum may be used in combination with aluminum, silver, lithium, indium, calcium, magnesium, or the like. The electrode has a function of collecting holes and electrons generated by light absorption. Therefore, it is preferable to use an electrode material suitable for collecting holes and electrons. . Examples of electrode materials suitable for collecting holes include materials having a high work function such as gold and ITO. On the other hand, an electrode material suitable for collecting electrons includes a material having a low work function such as aluminum.

  The film thickness of the transparent electrode can be arbitrarily selected according to the resistance value, but is usually 10 nm or more, especially 50 nm or more, and usually 1000 nm or less, especially 500 nm or less, more preferably 300 nm or less, particularly 100 nm or less. Is preferred. If the electrode is too thick, the transparency may be lowered and the cost may be increased. If the electrode is too thin, the series resistance is large and the performance tends to be lowered. The sheet resistance of the transparent electrode is preferably 300Ω / □ or less, more preferably 200Ω / □ or less, from the viewpoint of increasing the short-circuit current.

  In addition, as a formation method of a transparent electrode, any of dry processes, such as vacuum evaporation and a sputter | spatter, for example, and a wet process using conductive ink etc. can be used, for example. At this time, any conductive ink can be used. For example, a conductive polymer, a metal particle dispersion, or the like can be used. The electrode may be formed by laminating two or more layers, and may be subjected to a surface treatment for imparting electrical characteristics, wetting characteristics, and the like.

  The counter electrode is preferably a metal such as platinum, gold, silver, copper, iron, tin, zinc, aluminum, indium, chromium, lithium, sodium, potassium, cesium, calcium and magnesium, and alloys thereof, lithium fluoride And inorganic salts such as cesium fluoride, and metal oxides such as nickel oxide, aluminum oxide, lithium oxide, and cesium oxide. From the viewpoint of electrode protection, metals such as platinum, gold, silver, copper, iron, tin, aluminum, and indium and alloys of these metals are preferable.

The film thickness of the counter electrode can also be arbitrarily selected according to the resistance value, but is usually 10 nm or more, especially 50 nm or more, and usually 1000 nm or less, especially 500 nm or less, more preferably 300 nm or less, and particularly 100 nm or less. Is preferred.
As a method for forming the counter electrode, for example, a dry process such as vacuum deposition, electron beam, sputtering, plating, and CVD, or a wet process such as ion plating coating, sol-gel, spin coating, and inkjet. Any of these can be used. At this time, any conductive ink can be used. For example, a conductive polymer, a metal particle dispersion, or the like can be used. The electrode may be formed by laminating two or more layers, and may be subjected to a surface treatment for imparting electrical characteristics, wetting characteristics, and the like.

<Active layer>
In the photoelectric conversion element according to the present invention, the active layer includes a p-type semiconductor and an n-type semiconductor. In the photoelectric conversion element, light is absorbed by the active layer, electricity is generated at the interface between the p-type semiconductor and the n-type semiconductor, and the generated electricity is extracted from the electrode. As the layer structure of the active layer, a thin film stacked type in which a p-type semiconductor and an n-type semiconductor are stacked, a bulk heterojunction type in which a p-type semiconductor and an n-type semiconductor are mixed, and a p-type semiconductor and an n-type intermediate layer are formed. And a structure having a layer (i layer) mixed with a type semiconductor.

In the present invention, a conventionally known p-type semiconductor can be used, and examples thereof include a low molecular material and a high molecular material. As low molecular weight materials, condensed aromatic hydrocarbons such as naphthacene, pentacene, pyrene, fullerene; oligothiophenes containing 4 or more thiophene rings such as α-sexithiophene; thiophene ring, benzene ring, fluorene ring, naphthalene ring, Concatenated four or more anthracene rings, thiazole rings, thiadiazole rings, benzothiazole rings, etc .; phthalocyanine compounds such as copper phthalocyanine, zinc phthalocyanine, perfluoro copper phthalocyanine, porphyrin compounds such as tetrabenzoporphyrin and metal complexes thereof, and the like Examples also include macrocyclic compounds such as metal salts. Low molecular weight materials include film formation by vapor deposition or film formation by applying a soluble semiconductor precursor and then converting it to a semiconductor.

  The polymer material is not particularly limited, and examples thereof include conjugated polymer semiconductors such as polythiophene, polyfluorene, polythienylene vinylene, polyacetylene, and polyaniline; and polymer semiconductors such as alkyl-substituted oligothiophenes. Moreover, the polymer semiconductor which copolymerized 2 or more types of monomer units is also mentioned. These are semiconductors that are soluble in an organic solvent, and are preferable because a coating method can be used in the manufacturing process of an organic solar cell element.

  Conjugated polymer semiconductors are described in, for example, Handbook of Conducting Polymers, 3rd Ed. (2 volumes), 2007, Materials Science and Engineering, 2001, 32, 1-40, Pure Appl. Chem. Use polymers that can be synthesized by polymers described in known literature such as 2002, 74, 2031-3044, Handbook of THIOPHENE-BASED MATERIALS (2 volumes in total), 2009, or derivatives thereof, or combinations of the monomers described. Can do. Polymer or monomer substituents can be selected to control solubility, crystallinity, film formability, HOMO level or LUMO level.

The one kind of polymer semiconductor or a plurality of kinds of compound semiconductors may be used. The polymer material may have any self-organized structure in the film-formed state, or may be in an amorphous state.
Specific examples of the polymer material include the following, but are not limited thereto.

As the p-type semiconductor, it is preferable to use at least one of a porphyrin compound and a polymer semiconductor.
Moreover, although a conventionally well-known thing can be used also as an n-type semiconductor, the compound represented by the said General formula (1) of this invention can also be used. In addition, fullerene compounds, quinolinol derivative metal complexes represented by 8-hydroxyquinoline aluminum, condensed ring tetracarboxylic acid diimides such as naphthalene tetracarboxylic acid diimide, perylene tetracarboxylic acid diimide, perylene diimide derivatives, terpyridine metal complex, tropolone metal Complexes, flavonol metal complexes, perinone derivatives, benzimidazole derivatives, benzoxazole derivatives, thiazole derivatives, benzothiazole derivatives, benzothiadiazole derivatives, oxadiazole derivatives, thiadiazole derivatives, triazole derivatives, aldazine derivatives, bisstyryl derivatives, pyrazine derivatives, phenanthroline derivatives , Quinoxaline derivatives, benzoquinoline derivatives, bipyridine derivatives, borane derivatives, anthracene, pyrene Naphthacene, total fluoride condensed polycyclic aromatic hydrocarbon such as pentacene, single-walled carbon nanotubes, and the like. In addition, condensed ring tetracarboxylic acid diimides such as naphthalene tetracarboxylic acid diimide and perylene tetracarboxylic acid diimide, perylene diimide derivatives, benzimidazole derivatives, benzoxazole derivatives, thiazole derivatives, benzothiazole derivatives, benzothiadiazole derivatives, oxadiazole derivatives , Thiadiazole derivatives, triazole derivatives, pyrazine derivatives, phenanthroline derivatives, quinoxaline derivatives, bipyridine derivatives, and n-type polymers having a borane derivative as a constituent unit.
Among them, fullerene compounds, borane derivatives, thiazole derivatives, benzothiazole derivatives, benzothiadiazole derivatives, N-alkyl substituted naphthalene tetracarboxylic acid diimides and N-alkyl substituted perylene diimide derivatives and borane derivatives, thiazole derivatives, benzthiazoles A polymer comprising at least one of a derivative, a benzothiadiazole derivative, an N-alkyl-substituted naphthalenetetracarboxylic acid diimide and an N-alkyl-substituted perylene diimide derivative is preferable, and a fullerene compound and an N-alkyl-substituted polymer are preferable. Perylene diimide derivatives and N-alkyl substituted naphthalenetetracarboxylic acid diimides and N-alkyl substituted perylene diimide derivatives and N-alkyls n-type polymer as a constituent unit of the n-type polymer as a constituent unit of at least one of the substituted naphthalene tetracarboxylic diimide is more preferable. You may contain 1 type, or 2 or more types of these compounds.

<Fullerene compound>
Although there is no restriction | limiting in particular as a fullerene compound of this invention, General formula (n1), (n2), (
A fullerene compound having a partial structure represented by n3) or (n4) is preferred.

Fullerenes (FLN) in the general formulas (n1), (n2), (n3) and (n4) are carbon clusters having a closed shell structure. The carbon number of fullerene is not particularly limited as long as it is usually an even number of 60 to 130. As the fullerene, for example, C ₆₀ , C ₇₀ , C ₇₆ , C ₇₈ , C ₈₂ , C ₈₄ , C ₉₀
, C ₉₄ , C _96, and higher-order carbon clusters having more carbon than these. Among these, _C60 or _C70 is preferable, and _C60 is more preferable.

As fullerenes, carbon-carbon bonds on some fullerene rings may be broken. Some carbon atoms may be replaced with other atoms. Furthermore, a metal atom, a non-metal atom, or an atomic group composed of these may be included in the fullerene cage.
d, e, f and g are integers, and the sum of d, e, f and g is usually 1 to 5, preferably 1 to 3. The additional groups in (n1), (n2), (n3), and (n4) are added to the same 5-membered ring or 6-membered ring in the fullerene skeleton. L is an integer of 1-8. L is preferably an integer of 1 to 4, more preferably an integer of 1 to 2.

R ¹ in the general formula (n1) has an optionally substituted alkyl group having 1 to 14 carbon atoms, an optionally substituted alkoxy group having 1 to 14 carbon atoms, and a substituent. An aromatic group that may be present.
As an alkyl group, a C1-C10 alkyl group is preferable, a methyl group, an ethyl group, n-propyl group, isopropyl group, n-butyl group or isobutyl group is more preferable, and a methyl group and an ethyl group are especially preferable.

As an alkoxy group, a C1-C10 alkoxy group is preferable, a C1-C6 alkoxy group is more preferable, and a methoxy group and an ethoxy group are especially preferable.
As the aromatic group, an aromatic hydrocarbon group having 6 to 20 carbon atoms and an aromatic heterocyclic group having 2 to 20 carbon atoms are preferable, and a phenyl group, a thienyl group, a furyl group, and a pyridyl group are more preferable. More preferred are groups and thienyl groups.

The substituent which may be substituted on the alkyl group is a halogen atom or a silyl group. The halogen atom that may be substituted is preferably a fluorine atom.
The silyl group is preferably a diarylalkylsilyl group, a dialkylarylsilyl group, a triarylsilyl group, or a trialkylsilyl group, more preferably a dialkylarylsilyl group, and even more preferably a dimethylarylsilyl group.

R ^{2 to} R ⁴ in the general formula (n1) each represent an independent substituent, and may have a hydrogen atom, a C 1-14 alkyl group which may have a substituent, or a substituent. It is a good fluorinated alkyl group having 1 to 14 carbon atoms and an aromatic group which may have a substituent.
As an alkyl group, a C1-C10 alkyl group is preferable and a methyl group, an ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, and n-hexyl group are preferable.

As the fluorinated alkyl group, a perfluorooctyl group, a perfluorohexyl group, and a perfluorobutyl group are preferable.
The aromatic group is preferably an aromatic hydrocarbon group having 6 to 20 carbon atoms and an aromatic heterocyclic group having 2 to 20 carbon atoms, more preferably a phenyl group, a thienyl group, a furyl group and a pyridyl group, and a phenyl group and a thienyl group. Further preferred.

The substituent that the aromatic group may have is a fluorine atom, an alkyl group having 1 to 14 carbon atoms, a fluorinated alkyl group having 1 to 14 carbon atoms, an alkoxy group having 1 to 14 carbon atoms, and 3 to 3 carbon atoms. 10 aromatic groups are preferable, a fluorine atom and an alkoxy group having 1 to 14 carbon atoms are more preferable, and a methoxy group, an n-butoxy group, and a 2-ethylhexyloxy group are further preferable.
When an aromatic group has a substituent, although there is no limitation in the number, 1-3 are preferable and 1 is more preferable. When the aromatic group has a plurality of substituents, the types of the substituents may be different, but are preferably the same.

R ^{5 to} R ⁹ in the general formula (n2) are each independently a hydrogen atom or an alkyl group having 1 to 14 carbon atoms which may have a substituent or an aromatic group which may have a substituent. is there.
As the alkyl group, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an n-hexyl group and an octyl group are preferable, and a methyl group is more preferable.

The aromatic group is preferably an aromatic hydrocarbon group having 6 to 20 carbon atoms and an aromatic heterocyclic group having 2 to 20 carbon atoms, more preferably a phenyl group and a pyridyl group, and further preferably a phenyl group.
Although there is no limitation in particular as a substituent which an aromatic group may have, a fluorine atom, a C1-C14 alkyl group, a C1-C14 fluorinated alkyl group, and a C1-C14 alkoxy group are preferable. And more preferably an alkoxy group having 1 to 14 carbon atoms, and even more preferably a methoxy group.

When it has a substituent, the number is not limited, but 1 to 3 is preferable, and 1 is more preferable. The types of substituents may be different, but are preferably the same.
Ar ⁵ in the general formula (n3) is an optionally substituted aromatic hydrocarbon group having 6 to 20 carbon atoms or an aromatic heterocyclic group having 2 to 20 carbon atoms, and includes a phenyl group and a naphthyl group. Group, biphenyl group, phenanthryl group, anthryl group, fluorenyl group, pyrenyl group, perylenyl group, terphenyl group, thienyl group, furyl group, pyridyl group, pyrimidyl group, quinolyl group, quinoxalyl group, pyrazyl group, imidazolyl group, pyrazoyl group , Oxazole group, thiazole group, oxadiazole group, pyrrole group, triazole group, thiadiazole group, benzothienyl group, benzofuryl group, furanofuryl group, dibenzothienyl group, thienothienyl group, dibenzofuryl group, phenanthryl group, carbazoyl group, quinoxalyl group Benzoquinoxalyl group, carbazoyl group and Preferably E sulfonyl carbazoyl group, a phenyl group, a thienyl group, a furyl group, a thiazole group, a pyrrole group, a triazole group and a thiadiazole group is more preferred.

  Although there is no limitation as a substituent which may have, a fluorine atom, a chlorine atom, a hydroxyl group, a cyano group, a silyl group, a boryl group, an amino group which may be substituted with an alkyl group, an alkyl group having 1 to 14 carbon atoms A fluorinated alkyl group having 1 to 14 carbon atoms, an alkoxy group having 1 to 14 carbon atoms, an alkylcarbonyl group having 1 to 14 carbon atoms, an alkylthio group having 1 to 14 carbon atoms, an alkenyl group having 1 to 14 carbon atoms, carbon Preferred are an alkynyl group having 1 to 14 carbon atoms, an ester group, an arylcarbonyl group, an arylthio group, an aryloxy group, an aromatic hydrocarbon group having 6 to 20 carbon atoms, and a heterocyclic group having 2 to 20 carbon atoms. An alkyl group having 1 to 14 carbon atoms, an alkoxy group having 1 to 14 carbon atoms, an ester group, an alkylcarbonyl group having 1 to 14 carbon atoms, and an arylcarbonyl group are more preferable.

The alkyl group having 1 to 14 carbon atoms is more preferably a methyl group, an ethyl group, or a propyl group.
More preferably, it is a methoxy group, an ethoxy group, and a propoxyl group as a C1-C14 alkoxy group.
The alkylcarbonyl group having 1 to 14 carbon atoms is more preferably an acetyl group.

More preferably, the ester group is a methyl ester group or an n-butyl ester group.
As the arylcarbonyl group, a benzoyl group is more preferable.
When it has a substituent, although there is no limitation in the number, 1-4 are preferable and 1-3 are more preferable. When there are a plurality of substituents, the types may be different, but are preferably the same.
R ^{10 to} R ¹³ in the general formula (n3) may each independently have a hydrogen atom, an alkyl group that may have a substituent, an amino group that may have a substituent, or a substituent. It is a good alkoxy group or an alkylthio group which may have a substituent. R ²² or R ²³ may form a ring with either one of R ²⁴ or R ²⁵ .

The structure in the case of forming a ring can be represented by, for example, the general formula (n5) which is a bicyclo structure in which an aromatic group is condensed.
H in the general formula (n5) is the same as the above f, and U is an amino group which may be substituted with an alkyl group having 1 to 6 carbon atoms such as an oxygen atom, a sulfur atom, a methyl group and an ethyl group, C1-C6 alkoxyl group such as methoxy group, C1-C5 hydrocarbon group, C6-C2
An arylene group such as a phenylene group or an alkylene group having 1 or 2 carbon atoms which may be substituted with a 0 aromatic hydrocarbon group or an aromatic heterocyclic group having 2 to 20 carbon atoms.

R ^{14 to} R ¹⁵ in the general formula (n4) each independently have a hydrogen atom, an alkoxycarbonyl group, an alkyl group having 1 to 14 carbon atoms which may have a substituent, or a substituent. Is also a good aromatic group.
The alkoxy group in the alkoxycarbonyl group is preferably a hydrocarbon group having 1 to 12 carbon atoms and a fluorinated alkyl group, more preferably a hydrocarbon group having 1 to 12 carbon atoms, methyl group, ethyl group, n-propyl group, isopropyl group. Group, n-butyl group, isobutyl group, n-hexyl group, octyl group, 2-propylpentyl group, 2-ethylhexyl group, cyclohexylmethyl group and benzyl group are more preferable, methyl group, ethyl group, isopropyl group, n- Particularly preferred are butyl, isobutyl and n-hexyl groups.

  As the alkyl group, a linear alkyl group having 1 to 8 carbon atoms is preferable, and an n-propyl group is more preferable. There is no particular limitation on the substituent that the alkyl group may have, but an alkoxycarbonyl group is preferred. The alkoxy group of the alkoxycarbonyl group is preferably a hydrocarbon group having 1 to 14 carbon atoms and a fluorinated alkyl group, more preferably a hydrocarbon group having 1 to 14 carbon atoms, a methyl group, an ethyl group, an n-propyl group, an isopropyl group. Group, n-butyl group, isobutyl group, n-hexyl group, octyl group, 2-propylpentyl group, 2-ethylhexyl group, 2-ethylhexyl group, cyclohexylmethyl group and benzyl group are more preferable, methyl group and n-butyl group The group is particularly preferred.

  The aromatic group is preferably an aromatic hydrocarbon group having 6 to 20 carbon atoms and an aromatic heterocyclic group having 2 to 20 carbon atoms, preferably a phenyl group, a biphenyl group, a thienyl group, a furyl group or a pyridyl group, And more preferred are thienyl groups. . As the substituent that the aromatic group may have, an alkyl group having 1 to 14 carbon atoms, a fluorinated alkyl group having 1 to 14 carbon atoms, and an alkoxy group having 1 to 14 carbon atoms are preferable, and 1 to 14 carbon atoms are preferable. Are more preferable, and a methoxy group and a 2-ethylhexyloxy group are particularly preferable. When it has a substituent, there is no limitation in the number, However, Preferably it is 1-3, More preferably, it is 1. The types of substituents may be different or the same, preferably the same.

When it has a substituent, there is no limitation in the number, However, Preferably it is 1-3, More preferably, it is 1. The types of substituents may be different or the same, preferably the same.
As the structure of the general formula (n4), preferably R ¹⁴ and R ¹⁵ are both alkoxycarbonyl groups, R ¹⁴ and R ¹⁵ are both aromatic groups, R ¹⁴ is an aromatic group, and R ¹⁵ Is a 3- (alkoxycarbonyl) propyl group.

In addition, as a fullerene compound, the said 1 type compound or the mixture of multiple types of compound may be sufficient.
The fullerene compound can be formed by vapor deposition or coating. In particular, in order to be able to apply the coating method, it is preferable that the fullerene compound itself can be applied in a liquid state or that the fullerene compound is highly soluble in some solvent and can be applied as a solution.

The solvent for the fullerene compound of the present invention is not particularly limited as long as it is a nonpolar organic solvent, but a non-halogen solvent is preferred. Although halogen-based solvents such as dichlorobenzene are also possible, alternatives are required in terms of environmental impact.
Examples of non-halogen solvents include non-halogen aromatic hydrocarbons. Of these, toluene, xylene, cyclohexylbenzene and the like are preferable.

[Production method of fullerene compound]
Although there is no restriction | limiting in particular as a manufacturing method of the fullerene compound of this invention, For example, as a synthesis method of fullerene which has a partial structure (n1), international publication WO2008 / 059771 pamphlet, J. Org. Am. Chem. Soc. , 2008, 130 (46), 15429-15436, and can be implemented by a partial structure (n2).
As a method for synthesizing fullerene having the above, J. et al. Am. Chem. Soc. 1993, 115, 9798-9799, Chem. Mater. 2007, 19, 5363-5372 and Chem. Mater. The synthesis method of fullerene having a partial structure (n3) can be carried out by publicly known literature described in 2007, 19, 5194-5199, and Angew. Chem. Int. Ed. Engl. 1993, 32, 78-80, Tetrahedron Lett. 1997, 38, 285-288, International Publication WO2008 / 018931 Pamphlet, International Publication WO2009 / 086212 Pamphlet can be carried out according to known literature, and a method for synthesizing fullerene having a partial structure (n4) is J . Chem. Soc. Perkin Trans. 1, 1997 1595, Thin Solid Films 489 (2005) 251-256, Adv. Funct. Mater. 2005, 15, 1979-1987 and J. Org. Org. Chem. It can be carried out according to known documents described in 1995, 60, 532-538.

<N-alkyl-substituted perylene diimide derivatives>
The N-alkyl-substituted perylene diimide derivative according to the present invention is not particularly limited, and specifically, International Publication No. 2008/063609, International Publication No. 2009/115513, International Publication No. 2009/098250, Examples thereof include compounds described in International Publication No. 2009/000756 and International Publication No. 2009/091670. High electron mobility and absorption in the visible range are preferable because they contribute to both charge transport and power generation.

<Naphthalene tetracarboxylic acid diimide>
The naphthalene tetracarboxylic acid diimide according to the present invention is not particularly limited, but specifically described in International Publication No. 2008/063609, International Publication No. 2007/146250 and International Publication No. 2009/000756. Compounds. It is preferable from the viewpoint of high electron mobility, high solubility, and excellent coating properties.

<N-type polymer>
The n-type polymer according to the present invention is not particularly limited, but condensed ring tetracarboxylic acid diimides such as naphthalene tetracarboxylic acid diimide and perylene tetracarboxylic acid diimide, perylene diimide derivatives, benzimidazole derivatives, benzoxazole derivatives, thiazoles Derivatives, benzothiazole derivatives, benzothiadiazole derivatives, oxadiazole derivatives, thiadiazole derivatives, triazole derivatives, pyrazine derivatives, phenanthroline derivatives, quinoxaline derivatives, n-type polymers comprising at least one of bipyridine derivatives and borane derivatives Can be mentioned.
Among them, polymers having at least one of a borane derivative, a thiazole derivative, a benzothiazole derivative, a benzothiadiazole derivative, an N-alkyl-substituted naphthalenetetracarboxylic acid diimide and an N-alkyl-substituted perylene diimide derivative as a constituent unit Preferably, an n-type polymer having an n-type polymer having at least one of N-alkyl-substituted perylene diimide derivative and N-alkyl-substituted naphthalenetetracarboxylic acid diimide as a structural unit is more preferable. You may contain 1 type, or 2 or more types of these compounds. Specific examples include compounds described in International Publication No. 2009/098253, International Publication No. 2009/098250, International Publication No. 2010/012710, and International Publication No. 2009/098250. Since it has absorption in the visible region, it is preferable from the viewpoint of contributing to power generation, high viscosity, and excellent coating properties.

The thickness of the active layer is not particularly limited, but if it is less than 10 nm, there is a problem that uniformity is not sufficient and a short circuit is likely to occur. On the other hand, if the thickness of the layer containing different compounds exceeds 1000 nm Since internal resistance becomes large and the problem that the distance between electrodes increases and charge diffusion worsens arises, 10 to 1000 nm is preferable, and 50 to 200 nm is more preferable.

<Buffer layer>
The role of the buffer layer in the photoelectric conversion element includes exciton blocking, optical spacer, protection of the active layer, reverse electron transfer from the metal to the active layer, and the like. In the photoelectric conversion element according to the present invention, the buffer layer is preferably an electrode buffer layer adjacent to at least one of the electrodes, and the phosphine represented by the general formula (1) of the present invention is used as a material of the electrode buffer layer. A photoelectric conversion element material made of an oxide or a phosphine sulfide compound is used, and can be used for both the hole extraction layer and the electron extraction layer as the electrode buffer layer. It is preferably used.

  In addition to the photoelectric conversion material of the present invention, the electron extraction layer may be doped with an alkali metal, an alkaline earth metal, or a chloride thereof. The thickness of the electron extraction layer is not particularly limited, but is preferably 0.01 nm or more, on the other hand, preferably 40 nm or less, and more preferably 20 nm or less. If it is too thin, it tends to fail to function as a buffer layer. On the other hand, if it is too thick, it becomes difficult to take out electrons and the photoelectric conversion efficiency tends to decrease.

  The material of the hole extraction layer is not particularly limited as long as it can improve the efficiency of extracting holes from the active layer to the electrode. Specifically, PEDOT / PSS, polythiophene derivatives doped with polystyrene sulfonic acid, polythiophene, polypyrrole, polyacetylene, triphenylenediamine polypyrrole, conductive polymers doped with iodine, etc., copper phthalocyanine (CuPC), arylamine, etc. And the above-mentioned p-type semiconductors. A thin film of a metal such as gold, indium, silver, or palladium can also be used, and the thin film of a metal or the like can be used alone or in combination with the above organic material.

  The hole extraction layer and the electron extraction layer are disposed so as to sandwich the active layer between a pair of electrodes. That is, when the photoelectric conversion element according to the present invention includes both the hole extraction layer and the electron extraction layer, the electrode, the hole extraction layer, the active layer, the electron extraction layer, and the electrode are arranged in this order. When the photoelectric conversion element according to the present invention includes an electron extraction layer and does not include a hole extraction layer, the electrode, the active layer, the electron extraction layer, and the electrode are arranged in this order. The stacking order of the hole extraction layer and the electron extraction layer may be reversed, or at least one of the hole extraction layer and the electron extraction layer may be composed of a plurality of films.

  As a method for forming the hole extraction layer and the electron extraction layer, for example, when a material having sublimation property is used, the hole extraction layer and the electron extraction layer can be formed by a vacuum deposition method or the like. For example, a material soluble in a solvent is used. Can be formed by a wet coating method such as spin coating or inkjet. When a semiconductor material is used for the hole extraction layer, the precursor may be converted into a semiconductor material after forming the layer using the precursor, similarly to the low-molecular compound of the active layer.

The photoelectric conversion element according to the present invention may be configured by stacking elements in order to improve the conversion efficiency.
[Solar cell]
The photoelectric conversion element of this invention is used suitably as a photoelectric conversion element in a thin film solar cell. The solar cell of the present invention comprises a substrate (A), a photoelectric conversion element (B), a layer (C) containing a trapping agent that absorbs moisture and / or oxygen, and a gas barrier layer (D) covering the photoelectric conversion element. It is preferable to have a layer structure in which As described above, the photoelectric conversion element includes a pair of electrodes, and includes a layer (C) including an electrode opposite to the substrate and a trapping agent that absorbs the moisture and / or oxygen.
A single or a plurality of anticorrosion layers (E) may be provided between them.

<Substrate (A)>
A board | substrate (A) is a supporting member which supports a photoelectric conversion element (B), and is the same thing as the board | substrate mentioned in description of the above-mentioned photoelectric conversion element. Examples of the material for forming the substrate (A) include inorganic materials such as glass, sapphire, and titania; polyethylene terephthalate, polyethylene naphthalate, polyethersulfone, polyimide, polyamide, polystyrene, polyvinyl alcohol, ethylene vinyl alcohol copolymer, Fluorine resin, polyvinyl chloride, polyethylene, polypropylene, cyclic polyolefin, cellulose, acetyl cellulose, polyvinylidene chloride, aramid, polyphenylene sulfide, polyurethane, polycarbonate, poly (meth) acrylic resin, phenol resin, epoxy resin, polyarylate, polynorbornene Organic materials such as stainless steel, titanium, nickel, silver, gold, copper, and aluminum, and the like.

  Among these, glass, polyethylene terephthalate, polyethylene naphthalate, polyimide, poly (meth) acrylic resin, stainless steel, and aluminum are preferable from the viewpoint of easy formation of the photoelectric conversion element (B). In addition, the material of a base material may be 1 type, or may use 2 or more types of arbitrary combinations and combined use of a ratio. Further, the organic material may be reinforced with mechanical strength by containing reinforcing fibers such as carbon fibers and glass fibers. Moreover, the composite material by which the surface treatment for providing insulation to the said metal material was given may be sufficient.

<Photoelectric conversion element (B)>
The photoelectric conversion element (B) is the photoelectric conversion element described in the above section [Photoelectric conversion element].
<Layer (C) containing a scavenger that absorbs moisture and / or oxygen>
The layer (C) containing the trapping agent that absorbs moisture and / or oxygen is covered with the layer (C) containing the trapping agent that absorbs moisture and / or oxygen, thereby covering the photoelectric conversion element (B). B) to prevent deterioration due to moisture and oxygen, etc., and to maintain power generation efficiency over a long period of time, and is usually composed of a resin containing a scavenger that absorbs moisture and / or oxygen, and is in the form of a film Or it is preferable that it is a coating-film form.

  Here, unlike the gas barrier layer (D) described later, the layer (C) containing a moisture and / or oxygen-absorbing agent does not hinder the permeation of water and / or oxygen, but does not interfere with moisture and / or oxygen. It has a function of absorbing water. By providing the layer (C) containing a trapping agent that absorbs moisture and / or oxygen, even if the photoelectric conversion element is covered with a gas barrier layer (D) or the like to be described later, they escape and enter slightly. Moisture and / or oxygen is captured by this layer (C), and the influence of moisture and oxygen on the photoelectric conversion element can be eliminated.

  Here, as a resin containing a scavenger that absorbs moisture and / or oxygen, for example, polyethylene resin, polypropylene resin, cyclic polyolefin resin, polystyrene resin, acrylonitrile-styrene copolymer (AS resin), An acrylonitrile-butadiene-styrene copolymer (ABS resin), a polyvinyl chloride resin, a fluorine resin, a poly (meth) acrylic resin, a polycarbonate resin, or the like can be used. Among these, polyethylene resins, fluorine resins, cyclic polyolefin resins, and polycarbonate resins are preferable. In addition, the said resin may use 1 type and may use 2 or more types together by arbitrary combinations and a ratio.

Moreover, as the scavenger that absorbs moisture and / or oxygen, the scavenger that absorbs moisture includes general water-absorbing agents and desiccants. Specifically, for example, alkali metals, alkaline earth metals, Alkali earth metal oxides, alkali metal or alkaline earth metal hydroxides, silica gels, zeolite compounds, sulfates such as magnesium sulfate, sodium sulfate, nickel sulfate, organic metals such as aluminum metal complexes, aluminum oxide octylates Examples of the alkaline earth metal include Ca, Sr, and Ba, and examples of the alkaline earth metal oxide include CaO, SrO, and BaO, as well as Zr—Al—BaO. Can be mentioned. Among these, alkaline earth metals Ca, Sr, Ba and their oxides CaO, SrO, BaO, and aluminum metal complexes are preferable, and CaO, SrO, BaO are more preferable in terms of high moisture scavenging properties, and aluminum metal complexes. Is more preferable in that the scavenger can be made transparent. As a specific trade name preferable as a scavenger that absorbs moisture, for example, “OleDry” (manufactured by Futaba Electronics Co., Ltd.) can be mentioned. In addition, as for the capture | acquisition agent which absorbs these water | moisture and / or oxygen, 1 type of capture agents may be used, or 2 or more types of capture agents may be used.

Examples of the scavenger that absorbs oxygen include general oxygen scavengers. Specifically, for example, Fe, Mn, Zn, and inorganic salts such as sulfate, chloride, and nitrate of these metals. Ascorbic acid, hydrazine compounds, MXD6 nylon, ethylenically unsaturated hydrocarbons, and organic systems such as polymers having a cyclohexene group.
As a preferable combination of the scavengers constituting the layer (C) containing the scavenger that absorbs moisture and / or oxygen, in the case of the scavengers that absorb moisture, the alkaline earth metal Ca or Sr and the alkaline earth metal are used. A combination of the oxide CaO or SrO and a combination of the alkaline earth metal oxide CaO or SrO and an aluminum metal complex are preferable from the viewpoint of moisture trapping performance. In the case of a combination of a scavenger that absorbs moisture and a scavenger that absorbs oxygen, a combination of an alkaline earth metal oxide CaO or SrO and Fe, an alkaline earth metal oxide CaO or SrO and ascorbic acid Combination of alkaline earth metal oxide CaO or SrO and hydrazine compound, combination of aluminum metal complex and ascorbic acid, combination of aluminum metal complex and hydrazine compound achieves both moisture and oxygen absorption A combination of an alkaline earth metal oxide CaO or SrO and ascorbic acid, and a combination of an alkaline earth metal oxide CaO or SrO and a hydrazine compound are further preferable from the viewpoint of higher absorption performance.

  The layer (C) containing the trapping agent that absorbs moisture and / or oxygen can be formed by any method depending on the type of the trapping agent. For example, a film formed from a resin containing the trapping agent. A method of sticking a photoelectric conversion element with an adhesive, a resin solution containing a trapping agent is roll coated, gravure coated, knife coated, dip coated, curtain flow coated, spray coated, bar coated, die coated, spin coated, inkjet, dispenser The method etc. which apply | coat to a photoelectric conversion element by etc. can be used. Further, a film forming method such as plasma CVD, vacuum vapor deposition, ion plating, or sputtering may be used.

  The thickness of the layer (C) containing a scavenger that absorbs moisture and / or oxygen is not particularly limited, but is usually 5 μm or more, preferably 10 μm or more, more preferably 15 μm or more, It is 500 μm or less, preferably 400 μm or less, more preferably 300 μm or less. Increasing the thickness tends to increase the mechanical strength, and decreasing the thickness has an advantage of increasing flexibility and an advantage that the device can be thinned. Further, the layer (C) containing a scavenger that absorbs moisture and / or oxygen may be formed as a single layer or in a laminated state of two or more layers.

In the present invention, the moisture absorption capacity of the layer (C) containing a scavenger that absorbs moisture and / or oxygen is usually 0.1 mg / cm ² or more, preferably 0 as the amount of moisture absorption per unit area with respect to the laminated surface. .5mg / cm ² or more, and more preferably 1 mg / cm ² or more. The higher the numerical value, the higher the water absorption capacity, and the deterioration of the photoelectric conversion element can be suppressed. Moreover, although there is no restriction | limiting in an upper limit, it is 15 mg / cm < ² > or less normally.

The water absorption amount per unit volume is usually 1 mg / cm ³ or more, preferably 5 mg / cm ³ or more, more preferably 10 mg / cm ³ or more. The higher the numerical value, the higher the water absorption capacity, and the deterioration of the photoelectric conversion element can be suppressed. Moreover, although there is no restriction | limiting in an upper limit, it is usually 800 mg / cm < ³ > or less.
These moisture absorption amounts are calculated from the weight change before and after moisture absorption of the test specimen, the method of measuring the moisture content in the test specimen with a moisture measuring device, and the specimen is stored in a sealed container containing moisture. The water loss can be measured by a method of detecting with a moisture concentration meter. The method of calculating from the change in weight is preferable because it can be carried out easily. Specifically, after measuring the weight of the test specimen in a dry state, the specimen is stored in an environment where moisture exists, and the weight increase is eliminated. The weight at the time of recording is recorded, and the difference is taken as the moisture absorption amount. The storage environment in which moisture exists may be set as appropriate in terms of moisture absorption capacity as long as the conditions for the presence of moisture in excess of the moisture absorption amount of the specimen are satisfied. Specifically, in a test body having a large water absorption capacity, a humidity environment of 50 to 100% RH or more is used to shorten the test time, and in a test body having a low water absorption capacity, an environment in which the water concentration is appropriately controlled, for example, What is necessary is just to implement in 1 ppm-1% of range. As for the environment for weight measurement, a test body that irreversibly absorbs water may be weighed in a humidity environment of 50% RH or more, but a test body that reversibly absorbs water has a humidity of 85% RH or more. It is necessary to measure the weight in a high humidity environment.

The oxygen absorption capacity of the layer (C) containing a scavenger that absorbs moisture and / or oxygen is usually 0.01 ml / cm ² or more, preferably 0.05 ml as the amount of oxygen absorbed per unit area with respect to the laminated surface. / Cm ² or more, more preferably 0.1 ml / cm ² or more. The higher this value, the higher the oxygen absorption capacity, and the deterioration of the photoelectric conversion element can be suppressed. Moreover, although there is no restriction | limiting in an upper limit, it is usually 20 ml / cm < ² > or less.

The oxygen absorption amount per unit volume is usually 0.1 ml / cm ³ or more, preferably 0.5 mg / cm ³ or more, more preferably 1 mg / cm ³ or more. The higher the numerical value, the higher the water absorption capacity, and the deterioration of the photoelectric conversion element can be suppressed. Moreover, although there is no restriction | limiting in an upper limit, Usually, it is 200 mg / cm < ³ > or less.
These oxygen absorption amounts can be measured by a method in which a specimen is stored in a sealed container containing oxygen and the oxygen decrease is detected by an oxygen concentration meter. Record the oxygen concentration when there is no decrease in oxygen concentration, and use the difference from the oxygen concentration in the sealed container before the test as the oxygen absorption amount. The initial oxygen concentration in the sealed container may be set as appropriate so that oxygen exceeding the oxygen absorption amount of the test specimen exists and becomes a concentration suitable for the sensitivity of the oximeter. Further, the amount of the test body in the sealed container may be appropriately charged so that the oxygen decrease due to the absorption is equal to or higher than the detection sensitivity of the oximeter.

  Furthermore, the layer (C) containing a trapping agent that absorbs moisture and / or oxygen is visible light from the viewpoint of not impeding the light absorption of the photoelectric conversion element when the layer (C) is provided on the light receiving side surface of the solar cell. It is preferable to transmit light. For example, the transmittance of visible light (wavelength 360 to 830 nm) is usually 75% or more, preferably 80% or more, more preferably 85% or more, and still more preferably 90%, excluding loss due to partial reflection at the film interface. Above, particularly preferably 95% or more, and particularly preferably 97% or more. This is to convert more sunlight into electrical energy.

  In addition, since solar cells are often heated by receiving light, the layer (C) containing a trapping agent that absorbs moisture and / or oxygen preferably has heat resistance. From this viewpoint, the melting point or softening point of the constituent material of the layer (C) containing the scavenger that absorbs moisture and / or oxygen is usually 100 ° C. or higher, preferably 120 ° C. or higher, more preferably 130 ° C. or higher, Moreover, it is 350 degrees C or less normally, Preferably it is 320 degrees C or less, More preferably, it is 300 degrees C or less. By increasing the melting point or softening point, it is possible to reduce the possibility that the layer (C) containing the trapping agent that absorbs moisture and / or oxygen when the solar cell is used is melted and deteriorated.

In solar cells, the light-receiving surface and the back surface are often formed in a larger area than the other surfaces, and therefore moisture and oxygen tend to enter through these surfaces. From this viewpoint, in the present invention, the layer (C) containing a trapping agent that absorbs moisture and / or oxygen is provided between a gas barrier layer (D) and a photoelectric conversion element (B) described later.
In the one embodiment, a layer (C) containing a scavenger that absorbs moisture and / or oxygen is provided on the light receiving surface side of the photoelectric conversion element (B). In another embodiment, a layer (C) containing a trapping agent that absorbs moisture and / or oxygen is provided on the back side of the photoelectric conversion element (B) as necessary. Furthermore, as another embodiment, a layer (C) containing a scavenger that absorbs moisture and / or oxygen is provided on both the light receiving surface and the back surface. In that case, the layer (C) containing a scavenger that absorbs moisture and / or oxygen is positioned between the photoelectric conversion element (B) and a gas barrier layer (D) described later on both the light receiving surface and the back surface. It is preferable.

  Moreover, the layer (C) containing the trapping agent that absorbs moisture and / or oxygen disposed on the back surface of the photoelectric conversion element (B) opposite to the light receiving surface is a constituent member on the back side of the photoelectric conversion element (B). Since it is not always necessary to transmit visible light, a material that does not transmit visible light can be used. It is also possible to use the moisture or oxygen absorbent used as a layer containing more than the layer (C) containing a scavenger that absorbs moisture and / or oxygen. Examples of such absorbents include CaO, BaO, Zr—Al—BaO as moisture absorbents, and activated carbon, molecular sieves and the like as oxygen absorbents.

<Gas barrier layer (D)>
The gas barrier layer (D) is a layer that prevents permeation of water vapor and oxygen and has a function of covering the photoelectric conversion element (B) and preventing water vapor and oxygen from entering the photoelectric conversion element (B). The photoelectric conversion element (B) tends to be sensitive to moisture and oxygen, and in order to prevent the transparent electrode, the metal electrode and the organic semiconductor layer from being deteriorated by moisture and oxygen, the photoelectric conversion element (B) is changed to a gas barrier layer (D). By covering with, the photoelectric conversion element (B) can be protected from water vapor and oxygen, and the power generation capacity can be kept high.

  Specifically as a gas barrier layer (D), the resin film which provided the inorganic barrier layer on the resin film base-material surface is mentioned, for example. At this time, the inorganic barrier layer may be formed only on one side of the resin film substrate, or may be formed on both sides of the resin film substrate. In this case, the kind of inorganic barrier layer formed on both sides The numbers may be the same or different.

  Furthermore, the resin film which provided the unit layer which consists of two layers by which the inorganic barrier layer and the polymer layer were mutually arrange | positioned adjacent to the surface of a resin film base material is mentioned, for example. At this time, the unit layer composed of two layers in which the inorganic barrier layer and the polymer layer are arranged adjacent to each other may be formed only on one side of the resin film substrate or on both sides of the resin film substrate. In this case, the type and number of unit layers formed on both sides may be the same or different. In addition, the gas barrier layer formed on one surface of the resin film substrate has a unit layer composed of two layers in which an inorganic barrier layer and a polymer layer are arranged adjacent to each other as one unit. Even if only 1 unit of inorganic barrier layer and 1 polymer layer are provided, 2 units or more, for example, 2 to 5 units may be provided.

Further, in the case of a resin film provided with an inorganic barrier layer on the resin film substrate surface, and a unit layer composed of two layers in which the inorganic barrier layer and the polymer layer are arranged adjacent to each other on the resin film substrate surface. In any case of the provided resin film, a protective film may be provided on the surface on which the inorganic barrier layer is disposed for the purpose of protecting the inorganic barrier layer. Such a protective film may be the same material as the resin film substrate or may be different. Moreover, it is good also as a laminated body which bonded the surfaces which have arrange | positioned the inorganic barrier layer, and faced the resin film base material outside.

  In the case of the resin film in which the inorganic barrier layer is provided on the surface of the resin film base as described above, and the unit layer composed of two layers in which the inorganic barrier layer and the polymer layer are disposed adjacent to each other on the surface of the resin film base. As the resin film substrate in the case of the resin film provided with, for example, polyester resin, poly (meth) acrylic resin, methacrylic acid-maleic acid copolymer, polystyrene resin, fluorine resin, polyimide resin, Fluorinated polyimide resin, polyamide resin, polyvinyl alcohol resin, polyamideimide resin, polyetherimide resin, cellulose acylate resin, polyurethane resin, polyetheretherketone resin, polycarbonate resin, alicyclic Polyolefin resin, polyarylate resin, polyether Sulfone resins, polysulfone resins, cycloolefin copolymer resins, fluorene ring-modified polycarbonate resins, thermoplastic resins such as alicyclic modified polycarbonate resins.

  Among these resins, preferred examples include polyester resins, polyarylate resins, polyethersulfone resins, fluorene ring-modified polycarbonate resins, alicyclic modified polycarbonate resins, and the like. It is also preferable to use a condensation polymer containing spirobiindane or spirobichroman. Among polyester-based resins, biaxially stretched polyethylene terephthalate (PET) and biaxially stretched polyethylene naphthalate (PEN) are preferably used as a resin film substrate in the present invention because of excellent thermal dimensional stability. It is done. In addition, these resin may use 1 type and may use 2 or more types together by arbitrary combinations and a ratio.

  In addition, an anchor coat layer may be formed on these resin film base materials in order to improve adhesion to the inorganic barrier layer. Usually, the anchor coat layer is made of, for example, a polyester resin, a urethane resin, an acrylic resin, an oxazoline group-containing resin, a carbodiimide group-containing resin, an epoxy group-containing resin, an isocyanate group-containing resin, and a copolymer thereof. It is formed by applying seeds or two or more anchor coating agents.

  In this case, the thickness of the anchor coat layer is usually 0.005 μm or more, preferably 0.01 μm or more, and usually 5 μm or less, preferably 1 μm or less. If the thickness is less than or equal to the upper limit of this range, the slipperiness is good, and there is almost no peeling from the resin film substrate due to the internal stress of the anchor coat layer itself. Moreover, if it is more than the lower limit of this range, it can maintain a uniform thickness and is preferable.

  Moreover, in the case of the resin film which provided the inorganic barrier layer in the resin film base surface mentioned above, and consists of two layers by which the inorganic barrier layer and the polymer layer were arrange | positioned mutually adjacently on the resin film base material surface In the case of a resin film provided with a unit layer, the inorganic barrier layer is usually formed of a metal oxide, nitride, oxynitride or the like. In addition, the metal oxide, nitride, and oxynitride which form an inorganic barrier layer may be 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

  Examples of the metal oxide, nitride, oxynitride include Si, Al, Mg, In, Ni, Sn, Zn, Ti, Cu, Ce, Ta, and other oxides, nitrides, oxynitrides, and the like. Can be mentioned. Among them, in order to achieve both high barrier properties and high transparency, it is preferable to include aluminum oxide or silicon oxide, and it is particularly preferable to include silicon oxide from the viewpoint of moisture permeability, light transmittance, and the like. When the inorganic barrier layer is composed of two or more kinds of metal oxides, it is preferable to include aluminum oxide and silicon oxide as the metal oxide.

In the metal oxide, the ratio of each metal atom and oxygen atom is also arbitrary, but in order to improve the transparency of the inorganic barrier layer and prevent coloring, the oxygen atom ratio is determined from the stoichiometric ratio of the oxide. It is preferable that it is not extremely small. On the other hand, in order to improve the denseness of the inorganic barrier layer and increase the barrier property, it is preferable to reduce oxygen atoms. From these viewpoints, for example, when silicon oxide SiOx is used as the metal oxide, the value of x is particularly preferably 1.5 to 1.8. For example, when aluminum oxide AlOx is used as the metal oxide, the value of x is particularly preferably 1.0 to 1.4.

In addition, although there is no restriction | limiting in the formation method of an inorganic barrier layer, Generally it can carry out by sputtering method, a vacuum evaporation method, an ion plating method, plasma CVD method etc. For example, in the sputtering method, it can be formed by a reactive sputtering method using plasma using one or more kinds of metal targets and oxygen gas as raw materials.
Further, the thickness of the inorganic barrier layer tends to increase the barrier property when it is thick, but cracks are likely to occur when it is bent. Therefore, an appropriate thickness from these viewpoints is usually 5 nm or more, preferably 10 nm or more. Moreover, it is 1000 nm or less normally, Preferably it is 200 nm or less.

  In the case of the resin film in which the unit film composed of two layers in which the inorganic barrier layer and the polymer layer are disposed adjacent to each other is provided on the surface of the resin film substrate, any polymer may be used as the polymer layer. For example, a film that can be formed in a vacuum chamber can be used. In addition, the polymer which comprises a polymer layer may be 1 type, and may use 2 or more types of arbitrary combinations and combined use of a ratio. Accordingly, corresponding to these, one type of monomer may be used, or two or more types may be used in any combination and ratio.

  Examples of the compound that gives the polymer include siloxanes such as hexamethyldisiloxane, which can obtain polysiloxane as a polymer, and paraxylylenes such as diparaxylylene, which can obtain polyparaxylene as a polymer. Polyurethane (diisocyanate / glycol), polyurea (diisocyanate / diamine), polythiourea (dithioisocyanate / diamine), polythioether urethane (bisethyleneurethane / dithiol), polyimine (bisepoxy / primary amine) ), A polyaddition polymer such as polypeptide amide (bisazolactone / diamine), polyamide (diolefin / diamide) or the like, and a monomer capable of alternately repeating addition polymerization of two kinds of monomers. Moreover, the monofunctional, bifunctional, and polyfunctional acrylate monomer from which various acrylic polymers are obtained is mentioned. Examples of the monofunctional acrylate monomer include aliphatic acrylate monomers, alicyclic acrylate monomers, ether acrylate monomers, cyclic ether acrylate monomers, aromatic acrylate monomers, hydroxyl group-containing acrylate monomers, carboxy group-containing acrylate monomers, and the like. Can be mentioned. In order to obtain an appropriate evaporation rate, curing degree, curing rate, etc. as an acrylic polymer, it is preferable to use a combination of two or more of the above acrylate monomers.

  In addition, monomers that can produce photocationically cured polymers such as epoxy-based and oxetane-based polymers, vinyl acetate that can produce polyvinyl alcohol by saponifying the polymer, and copolymers that can be obtained with ethylene, acrylic acid, methacrylic acid , Ethacrylic acid, fumaric acid, maleic acid, itaconic acid, monomethyl maleate, monoethyl maleate, maleic anhydride, itaconic anhydride and other unsaturated carboxylic acids, and mixtures thereof and epoxy compounds such as glycidyl ether compounds A mixture etc. are also mentioned.

In order to polymerize these monomers to form a polymer, usually, a composition containing the monomer is applied or vapor deposited to form a film, and then contact heating with a heater or the like using a thermal polymerization initiator, infrared rays, microwaves, etc. Polymerization is carried out by radiant heating or irradiation with active energy rays using a photopolymerization initiator. In addition, as a light source in the case of active energy ray irradiation, for example, a mercury arc lamp, a xenon arc lamp, a fluorescent lamp, a carbon arc lamp, a tungsten-halogen radiation lamp, and irradiation light by sunlight can be used. Further, electron beam irradiation or atmospheric pressure plasma treatment can be performed.

Accordingly, the polymer layer can be formed by, for example, roll coating, gravure coating, knife coating, dip coating, curtain flow coating, spray coating, bar coating, or the like, and film formation such as vapor deposition or plasma CVD. Law.
The thickness of the polymer layer is usually 10 nm or more, and is usually 5000 nm or less, preferably 2000 nm or less, more preferably 1000 nm or less. By increasing the thickness of the polymer layer, the uniformity of the thickness can be easily obtained, and structural defects of the inorganic barrier layer can be efficiently filled with the polymer layer, and the barrier property tends to be improved. In addition, by reducing the thickness of the polymer layer, it becomes difficult for the polymer layer itself to generate cracks due to external forces such as bending, so that the barrier property can be improved.

  The above resin film having an inorganic barrier layer provided on the surface of the resin film base, or a unit layer composed of two layers in which the inorganic barrier layer and the polymer layer are disposed adjacent to each other are provided on the surface of the resin film base. The thickness of the gas barrier layer (D) by the resin film is not particularly limited, but is usually 10 μm or more, preferably 15 μm or more, more preferably 20 μm or more, and usually 500 μm or less, preferably 300 μm or less. Preferably it is 200 micrometers or less. Increasing the thickness tends to increase mechanical strength, and decreasing the thickness tends to increase flexibility.

In the present invention, the water vapor permeability of the gas barrier layer (D) in order to block the entry of moisture from the outside, 40 ° C., under 90% RH environment, 100μm thick, below 10 ^-1 g / m ² / day More preferably, it is 10 ⁻² g / m ² / day or less, more preferably 10 ⁻³ g / m ² / day or less, and particularly preferably 10 ⁻⁴ g / m ² / day or less. However, the current technology is transparent and flexible, and the barrier performance increases, so the manufacturing cost will increase accordingly. Is in the range of 10 ⁻³ g / m ² / day to 10 ⁻⁴ g / m ² / day, which is the most preferable water vapor transmission performance. The water vapor transmission rate can be measured in a 40 ° C. and 90% RH environment by a measurement using an apparatus equipped with a humidity sensor, an infrared sensor, and a gas chromatograph according to JIS K7129, or by the cup method (JIS Z0208). .

Further, the oxygen permeation performance required for the gas barrier layer (D) varies depending on the type of the photoelectric conversion element (B) and the like. For example, in general, the oxygen permeability per unit area (1 m ² ) per day is preferably 1 cc / m ² / day / atm or less in a 25 ° C. environment with a thickness of 100 μm, preferably 1 × 10 ^-1 cc / m ² / day / atm or less is more preferable, and 1 × 10 ⁻² cc / m ² / day / atm or less is further preferable, and 1 × 10 ⁻³ cc / m ² is more preferable.
/ Day / atm or less is preferable, and 1 × 10 ⁻⁴ cc / m ² / day /
It is particularly preferably not more than atm, and particularly preferably not more than 1 × 10 ⁻⁵ cc / m ² / day / atm. There is an advantage that the deterioration due to the oxidation of the element can be suppressed as the oxygen does not permeate. The oxygen transmission rate can be measured with an apparatus based on a differential pressure method according to JIS K7126A, or an apparatus equipped with an infrared sensor and gas chromatograph based on an isobaric method according to JIS K7126B.

The gas barrier layer (D) preferably transmits visible light when used on the light incident / exit surface of the solar cell. For example, the transmittance of visible light (wavelength 360 to 830 nm) is usually 75% or more, preferably 80% or more, more preferably 85% or more, still more preferably 90% or more, particularly preferably 95% or more. Among these, 97% or more is particularly preferable. This is to convert more sunlight into electrical energy. Further, when it is used on a surface opposite to the light incident / exiting surface of the solar cell, it is not always necessary to transmit visible light, and may be opaque.

  Further, since the solar cell is often heated by receiving light, the gas barrier layer (D) preferably has heat resistance. From this viewpoint, the melting point or softening point of the constituent material of the gas barrier layer (D) is usually 100 ° C. or higher, preferably 120 ° C. or higher, more preferably 130 ° C. or higher, and usually 350 ° C. or lower, preferably 320 ° C. Below, more preferably 300 ° C. or less. By increasing the melting point or softening point, it is possible to reduce the possibility that the gas barrier layer (D) is melted or deteriorated when the solar cell is used.

  In the present invention, among the above gas barrier layers (D), for example, SiOx or SiOx Ny (value of x) is preferably formed on the surface of a base film such as polyethylene terephthalate (PET) or polyethylene naphthalate (PEN). Is preferably 1.5 to 1.8, and Y is an integer), and examples thereof include a resin film obtained by vacuum-depositing an inorganic barrier layer by a vacuum film-forming method.

  In the present invention, the gas barrier layer (D) includes an inorganic barrier layer using an inorganic barrier material. In the case of an organic barrier material, the gas barrier layer (D) is mainly a barrier material while dissolving and diffusing a gas such as water vapor in the barrier material. In most cases, the barrier property is achieved with the thickness of the gas. In this case, if the amount of dissolved gas in the barrier material increases to near the saturation solubility by timekeeping, the gas cannot be shut off in the photoelectric conversion element. In contrast, SiOx and SiOx Ny inorganic barrier materials do not absorb moisture or react with moisture, and can achieve barrier performance by regulating the free volume.

In the present invention, the water vapor permeability is cited as one of the gas barrier performances of the gas barrier layer (D). The water vapor barrier is one of the most important functions, and the water vapor barrier is usually used. This is because it is one of the most difficult (easy to permeate) among gases such as oxygen and low molecular weight components such as volatile components, alkalis and acids which are problematic.
In the present invention, if the gas barrier layer (D) is laminated in the order described in the present invention so as to cover the photoelectric conversion element (B) and protect it from moisture and oxygen, the gas barrier layer (D) is limited to its formation position. However, the photoelectric conversion element (B) is provided on the surface opposite to the substrate. Moreover, you may cover the back surface (surface on the opposite side to a light-receiving surface) of the board | substrate installation surface of a photoelectric conversion element (B) with the same gas barrier layer (D). This is because the front and back surfaces of solar cells are often formed in a larger area than the other surfaces. Then, the edge of the gas barrier layer (D) is sealed with a sealing material, and the photoelectric conversion element (B) is placed in a space surrounded by the gas barrier layer (D) and the sealing material, so that photoelectric conversion is performed. The element (B) can be protected from moisture and oxygen. In addition, when the back surface protection sheet mentioned later has high gas barrier performance, it can serve as a gas barrier layer (D) by the use.

<Anti-corrosion layer (E)>
In the present invention, the solar cell has a single or plural anticorrosion layers (E) between the electrode opposite to the substrate (A) and the layer (C) containing a trapping agent that absorbs moisture and / or oxygen. May be provided. Thus, the layer (C) containing the trapping agent that absorbs moisture and / or oxygen is prevented from coming into direct contact with the electrode, and the trapping agent that absorbs moisture and / or oxygen in the layer (C) is applied to the electrode. Prevents electrode corrosion due to diffusion. In addition, the anticorrosion layer (E) may be provided on the gas barrier layer (D), the portion where the photoelectric conversion element (B) on the substrate (A) does not exist, in addition to the above-described arrangement position.

For the anticorrosion layer (E), a resin film or a resin film having a gas barrier property is used. In consideration of the simplicity and cost of the assembly process of the solar cell, the form of the gas barrier resin film is most preferable. In the resin film, when the resin film having gas barrier properties is directly formed on the photoelectric conversion element (B), in the coating method, the solvent of the coating solution penetrates from the pinhole of the electrode into the photoelectric conversion element (B). On the other hand, the dry film formation method with a vacuum process is not preferable because it is a batch process, and the production efficiency is extremely inferior, and the photoelectric conversion element ( B) is not preferred because it may be damaged.

  Specifically, the material constituting the anticorrosion layer (E) in the present invention includes, for example, a polyethylene resin, a polypropylene resin, a cyclic polyolefin resin, an α-olefin-maleic anhydride copolymer, a polystyrene resin, Acrylonitrile-styrene copolymer (AS resin), styrene-butadiene copolymer (SB resin), acrylonitrile-butadiene-styrene copolymer (ABS resin), polyvinyl chloride resin, polyvinylidene chloride resin, polyvinyl acetate Resin, ethylene-vinyl acetate copolymer, polyvinyl alcohol resin, ethylene-vinyl alcohol copolymer, polyvinyl butyral resin, polyvinyl pyrrolidone resin, fluorine resin, poly (meth) acrylic resin, polycarbonate Resin, polyethylene terephthalate, polyethylene Polyester resins such as ethylene naphthalate, polyimide resins, polyamideimide resins, polyarylate resins, polyamide resins, silicone resins, polysulfone resins, polyethersulfone resins, polyphenylene sulfide resins, polyurethane resins, Examples thereof include polybenzimidazole resins, phenol resins, melamine resins, urea resins, resorcinol resins, xylene resins, epoxy resins, acetal resins, and cellulose resins. Preferred are polyethylene resins, cyclic polyolefin resins, ethylene-vinyl acetate copolymers, fluorine resins, poly (meth) acrylic resins, polycarbonate resins, polyester resins, polyimide resins, epoxy resins, etc. More preferred are polyethylene resins, fluorine resins, poly (meth) acrylic resins, polyester resins, polyimide resins, epoxy resins and the like. Of these, poly (meth) acrylic resins and epoxy resins are particularly preferable because they can provide an adhesive function.

The anticorrosion layer (E) may be one or more layers, and may be composed of a plurality of layers. In the case of a plurality of layers, a combination such as a polyester resin and a poly (meth) acrylic resin, a polyester resin and an epoxy resin is preferable in that it has both transparency and heat resistance and can provide an adhesive function.
The anticorrosion layer (E) can be formed by any method depending on the type of resin material to be used. For example, a method of forming a film or sheet by a melt extrusion molding method, a solution casting method, a calendar method, etc. Wet deposition that forms a resin film by applying a resin material solution by roll coating, gravure coating, knife coating, dip coating, curtain flow coating, spray coating, bar coating, die coating, spin coating, ink jet, dispenser, etc. The method can be used. In addition, dry film forming methods such as plasma CVD, vacuum deposition, ion plating, and sputtering can also be used. Furthermore, after forming a film or sheet or after film formation, polymerization, crosslinking, curing reaction, and the like may be performed by heating with a heater, infrared rays, microwaves, etc., irradiation with ultraviolet light and / or visible light, and the like.

  The thickness per layer of the anticorrosion layer (E) is usually 5 to 500 μm, preferably 10 to 200 μm, and more preferably 20 to 100 μm. If the upper limit is exceeded, the thickness of the flexible solar cell increases and it becomes difficult to bend, and a distance from the metal electrode of the element arises, so that the scavenger reaches moisture around the metal electrode, oxygen, etc. There is a risk that it cannot be absorbed efficiently. On the other hand, if the value is below the lower limit, the suppression of alkali diffusion becomes insufficient and there is a possibility that the deterioration of the electrode cannot be prevented.

In the present invention, the anticorrosion layer (E) includes the relationship with the water vapor transmission rate (Pd) of the gas barrier layer (D) as the water vapor transmission rate (Pe) as a characteristic of the whole layer in the case of a plurality of layers. In a 90% RH environment, the relationship is preferably Pd <Pe ≦ 15 g / m ² / day, more preferably Pd <Pe ≦ 5 g / m ² / day, and Pd × 5 <Pe. More preferably, the relationship is ≦ 1 g / m ² / day, and Pd × 10 <Pe ≦ 1 g / m ²
/ Day is particularly preferable, and Pd × 10 <Pe ≦ 0.1 g / m ² / day.
It is particularly preferable that The measurement method here is also according to the method described above.

  When the water vapor transmission rate (Pe) of the anticorrosion layer (E) is larger than the upper limit, moisture, oxygen, and scavenger leaking from the layer (C) containing the scavenger that absorbs moisture and / or oxygen are contained. There is a possibility that alkali or acid generated by the reaction cannot be sufficiently blocked, and deterioration of the photoelectric conversion element (B) cannot be prevented. In addition, in the solar cell manufacturing process, an organic solvent or low molecular weight component volatilized from the adhesive or pressure sensitive adhesive used in the process cannot be sufficiently blocked, and a scavenger that absorbs moisture and / or oxygen is used. After the layer (C) is altered and assembled into a solar cell, moisture and / or oxygen cannot be sufficiently absorbed, and deterioration of the photoelectric conversion element (B) may not be prevented.

  When the water vapor transmission rate (Pe) of the anticorrosion layer (E) is smaller than the lower limit defined from the relationship with the water vapor transmission rate (Pd) of the gas barrier layer (D), The anticorrosion layer (E) cannot sufficiently absorb moisture or oxygen that has entered the photoelectric conversion element (B) or remains during the assembly process, and prevents deterioration of the photoelectric conversion element (B). There is a risk of not being able to. This is particularly remarkable when the water vapor transmission rate (Pd) of the gas barrier layer (D) is low, aiming at a long life.

  As one of the preferable aspects of the anticorrosion layer (E) satisfying the water vapor transmission rate, it is also preferable to include an inorganic material film formed by a vacuum film forming method as a layer. In the case of organic barrier materials, in most cases, the barrier property is achieved mainly by the thickness of the barrier material while dissolving and diffusing a gas such as water vapor in the barrier material. In this case, the amount of dissolved gas in the barrier material is measured. In contrast, when the gas reaches the vicinity of the saturation solubility, it becomes impossible to shut off the gas into the photoelectric conversion element, whereas for example, an inorganic barrier material such as SiOx, SiOx Ny (X = 1.5 to 2, Y is an integer) This is because the barrier performance can be achieved by regulating the free volume without absorbing or reacting with moisture.

In the present invention, the gas barrier performance is defined by the water vapor transmission rate as the anticorrosion layer (E). This is because the water vapor barrier is one of the most important functions, and the water vapor barrier is usually a problem. This is because it is one of the most difficult to block (easily permeate) among low molecular weight components such as gases such as oxygen, volatile components, alkalis and acids.
A more preferable function is one having an adhesive function. By having an adhesive function, the element and the capture agent that absorbs moisture and / or oxygen are fixed, and therefore, there is no possibility that the capture agent is displaced and contacts the element electrode when the solar cell is deformed by bending or the like. Further, during the manufacture of the solar cell, the anticorrosion layer (E), the layer containing the scavenger (C), and the gas barrier film (D) are laminated on the substrate (A) and the photoelectric conversion element (B). In addition, there is an advantage that the layer (C) containing the trapping agent is displaced and does not come in contact with the device electrode.

  Moreover, it is preferable that it has alkali resistance as a property of anticorrosion layer (E) itself. The scavenger component may react with moisture to generate alkali. In that case, if the anticorrosion layer (E) is not resistant to alkali, the alkali may permeate and cause corrosion and deterioration of the electrode. Further, it is preferable that no acid is generated from the anticorrosion layer (E). When the acid comes into contact with the electrode, the electrode may corrode and deteriorate. Examples of the resin material that generates an acid include vinyl acetate resins such as ethylene-vinyl acetate copolymers.

As another typical characteristic in the anticorrosion layer (E), the oxygen transmission capacity varies depending on the photoelectric conversion element (B). For example, in general, a unit area at a thickness of 100 μm in an environment of 25 ° C. The oxygen permeability per day of (1 m ² ) is preferably 500 cc / m ² / day / atm or less, more preferably 100 cc / m ² / day / atm or less, more preferably 10 cc / m ² / More preferably, it is not more than day / atm, and particularly preferably not more than 1 cc / m ² / day / atm. When the oxygen barrier performance is within such a range, deterioration of the element due to oxygen can be suppressed. Moreover, when the scavenger used absorbs oxygen, it is preferable that it is a value more than the oxygen permeability of a gas barrier layer (D). When the oxygen permeability is lower than that of the gas barrier layer (D), the scavenger captures oxygen outside the element sealing region, that is, outside the gas barrier layer (D), and the original purpose of preventing element deterioration is lost. I will be broken. The oxygen permeability can be measured by the method described above.

  In addition, the adhesion function of the anticorrosion layer (E) is required to have an adhesion ability to the layer (C) containing the device electrode and the trapping agent. As a standard of the adhesive ability, the adhesive strength is 0.1 N / mm or more, preferably 0.4 N / mm or more, more preferably 1 N / mm or more. If the adhesion function is below this lower limit, the scavenger may easily shift and contact the device electrode, causing electrode deterioration.

Moreover, as an index of alkali resistance of the anticorrosion layer (E), it is preferable that it can withstand a test based on ASTM D543. Specifically, it is preferable that there is no abnormality in the appearance after immersion in a 1% sodium hydroxide solution for 24 hours, and the dimensional change is 5% or less, more preferably 1% or less.
Further, the water absorption of the anticorrosion layer (E) is generally preferably 0.005 to 1%, more preferably 0.01 to 0.5%, still more preferably 0.02 to 0.3%. When this upper limit is exceeded, alkali diffusion is promoted by the absorbed moisture, and the electrode corrosion prevention effect may be inferior. On the other hand, below the lower limit, the moisture at the interface between the device electrode and the anticorrosion layer (E) is blocked by the anticorrosion layer (E) and may not be absorbed by the scavenger.

  When the anticorrosion layer (E) is used on the light-receiving surface side of the thin-film solar cell, it is preferable to transmit visible light from the viewpoint of not preventing light absorption. For example, the transmittance of visible light (wavelength 360 to 830 nm) is usually 75% or more, preferably 80% or more, more preferably 85% or more, and still more preferably 90%, excluding loss due to partial reflection at the film interface. More preferably, it is 95% or more, most preferably 97% or more. This is to convert more sunlight into electrical energy. On the other hand, when the anticorrosion layer (E) is used on the side opposite to the light receiving surface of the organic thin film solar cell, it is not always necessary to transmit visible light, and may be opaque.

  Furthermore, since the solar cell is often heated by receiving light, the anticorrosion layer (E) preferably has heat resistance. From this viewpoint, the melting point or softening point of the constituent material is usually 100 ° C. or higher, preferably 120 ° C. or higher, more preferably 130 ° C. or higher, and usually 350 ° C. or lower, preferably 320 ° C. or lower, more preferably 300 ° C. It is below ℃. The glass transition temperature is usually 0 ° C. or higher, preferably 30 ° C. or higher, more preferably 60 ° C. or higher, and usually 300 ° C. or lower, preferably 200 ° C. or lower, more preferably 160 ° C. or lower. By using a material having a high melting point or a high softening point / high glass transition temperature, the heat resistance is improved, and the possibility that the anticorrosion layer (E) is melted and deteriorated when the solar cell is used can be reduced.

<Other members; seal materials>
The sealing material is a member that seals the edges of the laminate composed of (A) to (E) and the like so as to prevent moisture and oxygen from entering the inside thereof. In particular, at least the edge of the photoelectric conversion element (B) is provided at a position where it can be sealed, so that moisture and oxygen do not enter at least the photoelectric conversion element (B). Usually, 0.5 ~
A rectangular shape is coated with a thickness of 100 mm, preferably 1 to 80 mm, more preferably 2 to 50 mm, and the photoelectric conversion element (B) is enclosed inside.

  Examples of the material constituting the sealing material include fluorine resin, silicone resin, acrylic resin, α-olefin-maleic anhydride copolymer, urethane resin, cellulose resin, vinyl acetate resin, ethylene-acetic acid. Vinyl copolymer, epoxy resin, polyvinyl chloride resin, phenol resin, melamine resin, urea resin, resorcinol resin, polyamide resin, polyimide resin, polystyrene resin, polyvinyl butyral resin, polybenzimidazole Examples thereof include polymers such as resin, chloroprene rubber, nitrile rubber, and styrene butadiene copolymer rubber, and the sealing material may be formed of one material or two or more materials.

  The sealing material is not particularly limited as long as it can be coated without a gap between the outermost substrate (A) and the gas barrier layer (D). For example, adhesion by curing of the sealing material, solvent -Adhesion by volatilization of the dispersion medium, adhesion by a hot melt agent, adhesion by simply pasting, and the like can be mentioned. From the viewpoint of facilitating the production, it is preferable to simply adhere to each other. Moreover, when barrier property is calculated | required for a sealing material, since the intermolecular bridge | crosslinking by hardening makes gas barrier property favorable, the adhesion | attachment by hardening is preferable.

  Examples of the curing method at that time include curing by a chemical reaction at normal temperature, heat curing, photocuring with visible light or ultraviolet light, electron beam curing, anaerobic curing, and the like. Among these, heat curing and ultraviolet curing are preferable because curing control can be performed precisely. Further, as the properties of the sealing material, liquid, gel, sheet, and the like are appropriately selected depending on the bonding method, but the sheet shape is preferable from the viewpoint of not causing problems such as dripping in the sealing process.

Incidentally, the degree of water vapor permeability required of the sealant, 40 ° C., under 90% RH environment, with 100μm thickness is preferably not more than 500g / m ² / day as water vapor transmission rate, 100 g / m ² / Day or less is more preferable, 30 g / m ² / day or less is more preferable, 10 g / m ² / day is particularly preferable, and 1 g / m ² / day is most preferable. By applying such a sealing material, it is possible to suppress the permeation of moisture from the edge of the solar cell laminate and operate the solar cell for a long period of time.

In addition, as a standard for the adhesion ability of the sealing material to the adherend, the adhesive strength is preferably 2 N / mm or more, more preferably 4 N / mm or more, and 10 N / mm or more. Further preferred. If it falls below this lower limit, it may be easily peeled off and moisture and oxygen may enter, which may cause deterioration of the solar cell.
Furthermore, since the solar cell is often heated by receiving light, the sealing material preferably has heat resistance. From this viewpoint, the melting point or softening point of the constituent material of the sealing material is usually 100 ° C. or higher, preferably 120 ° C. or higher, more preferably 130 ° C. or higher, and usually 350 ° C. or lower, preferably 300 ° C. or lower. Preferably it is 280 degrees C or less. If the melting point or softening point is too low, the sealing material may melt during use of the solar cell.

<Other members; sealing material>
In the present invention, a sealing material may be used so as to sandwich the photoelectric conversion element usually for reinforcement of the solar cell. The sealing material preferably has a high strength from the viewpoint of maintaining the strength of the solar cell, and the specific strength is related to the strength of the solar cell body and is difficult to define unconditionally. It is preferable to have a strength that has good bending workability and does not cause peeling of the bent portion.

As a material constituting the sealing material, for example, an ethylene-vinyl acetate copolymer (EVA) resin can be used, and a film thereof can be used. However, when the EVA resin is subjected to a crosslinking treatment, the crosslinking treatment includes Since it takes a relatively long time, it may cause a reduction in the production rate and production efficiency of the solar cell, and when used for a long period of time, the decomposition gas (acetic acid gas) of the EVA resin or the EVA resin itself has. The vinyl acetate group may adversely affect the photoelectric conversion element and reduce power generation efficiency. In this case, as the other sealing material, a film of propylene-ethylene-other α-olefin copolymer may be used. In addition, the sealing material may be formed with 1 type of material, and may be formed with 2 or more types of materials. Moreover, the sealing material may be formed of a single layer film or a laminated film including two or more layers.

  The thickness of the sealing material is not particularly limited, but is usually 100 μm or more, preferably 150 μm or more, more preferably 200 μm or more, and usually 1000 μm or less, preferably 800 μm or less, more preferably 600 μm or less. Increasing the thickness tends to increase the overall strength of the solar cell, decreasing the thickness increases flexibility, and tends to improve the visible light transmittance.

  When the sealing material is used on the light-receiving surface side of the thin-film solar cell, it is preferable to transmit visible light from the viewpoint of preventing light absorption. For example, the transmittance of visible light (wavelength 360 to 830 nm) is usually 75% or more, preferably 80% or more, more preferably 85% or more, still more preferably 90% or more, particularly preferably 95% or more, most Preferably it is 97% or more. This is to convert more sunlight into electrical energy. On the other hand, when a sealing material is used on the side opposite to the light receiving surface of the thin-film solar cell, it is not always necessary to transmit visible light and may be opaque.

  In addition, since the solar cell is often heated by receiving light, the sealing material preferably has heat resistance. From this viewpoint, the melting point of the constituent material of the sealing material is usually 100 ° C. or higher, preferably 120 ° C. or higher, more preferably 130 ° C. or higher, and usually 350 ° C. or lower, preferably 320 ° C. or lower, more preferably. It is 300 degrees C or less. By increasing the melting point, it is possible to reduce the possibility of the sealing material melting and deteriorating when the solar cell is used.

  The sealing material may be provided with functions such as ultraviolet blocking, heat ray blocking, conductivity, antireflection, antiglare, light diffusion, light scattering, wavelength conversion, gas barrier properties, and the like. In particular, in the case of a solar cell, it is preferable to have an ultraviolet blocking function because it is exposed to strong ultraviolet rays from sunlight. As a method of imparting such a function, a layer having such a function may be formed on the sealing material by coating film formation or the like, or an additive having such a function is dispersed in a constituent material, etc. You may make it contain.

<Other components: Weatherproof protective sheet>
The weather-resistant protective sheet is a sheet or film that protects a solar cell from a solar cell installation environment related to temperature change, humidity change, light, wind and rain, and the like. By covering the surface of the solar cell with a weather-resistant protective sheet, the solar cell constituent material, particularly the photoelectric conversion element (B) is protected, and there is an advantage that high power generation capability can be obtained over a long period without deterioration.

Since the weather-resistant protective sheet is positioned on the outermost surface of the solar cell, it has suitable performance as a surface covering material such as weather resistance, heat resistance, transparency, water repellency, stain resistance, mechanical strength, and the like. It preferably has the property of maintaining the performance for a long period of time in outdoor exposure.
The material constituting the weatherproof protective sheet is not particularly limited as long as it can protect the solar cell. For example, a polyethylene resin, a polypropylene resin, a cyclic polyolefin resin, acrylonitrile-styrene (AS ) Resin, acrylonitrile-butadiene-styrene (ABS) resin, polyvinyl chloride resin, fluorine resin, polyester resin such as polyethylene terephthalate, polyethylene naphthalate, phenol resin, polyacrylic resin, polyamide resin , Polyimide resins, polyamideimide resins, polyurethane resins, cellulose resins, silicone resins, polycarbonate resins, etc., even if they are formed of one of those materials, they are formed of two or more materials May simply be those Films, or used as two or more layers of laminated film. In the case of a laminated film or the like, surface treatment such as corona treatment or plasma treatment may be performed in order to improve adhesion with other films.

  Of these, fluororesins are preferred, and specific examples thereof include polytetrafluoroethylene (PTFE), 4-fluoroethylene-perchloroalkoxy copolymer (PFA), 4-fluoroethylene-6-fluoride. Propylene copolymer (FEP), 2-ethylene-4-fluorinated ethylene copolymer (ETFE), poly-3-fluoroethylene chloride (PCTFE), polyvinylidene fluoride (PVDF), and polyvinyl fluoride (PVF) Etc.

The thickness of the weatherproof protective sheet is not particularly limited, but is usually 10 μm or more, preferably 15 μm or more, more preferably 20 μm or more, and usually 200 μm or less, preferably 180 μm or less, more preferably 150 μm or less. is there. Increasing the thickness tends to increase mechanical strength, and decreasing the thickness tends to increase flexibility.
In addition, when a weatherproof protective sheet is used for the light-receiving surface side of a solar cell, what permeate | transmits visible light from a viewpoint which does not prevent light absorption is preferable. For example, the transmittance of visible light (wavelength 360 to 830 nm) is usually 75% or more, preferably 80% or more, more preferably 85% or more, still more preferably 90% or more, particularly preferably 95% or more, most Preferably it is 97% or more. This is to convert more sunlight into electrical energy. On the other hand, when using a weatherproof protective sheet on the side opposite to the light receiving surface of the solar cell, it is not always necessary to transmit visible light, and may be opaque.

  In addition, since solar cells are often heated by receiving light, it is preferable that the weather-resistant protective sheet also has heat resistance. From this viewpoint, the melting point or softening point of the constituent material of the weatherproof protective sheet is usually 100 ° C. or higher, preferably 120 ° C. or higher, more preferably 130 ° C. or higher, and usually 350 ° C. or lower, preferably 320 ° C. or lower. More preferably, it is 300 ° C. or lower. By increasing the melting point or softening point, it is possible to reduce the possibility that the weatherproof protective sheet is melted and deteriorated when the photoelectric conversion element (B) is used.

  In addition, UV protection, heat ray blocking, antifouling, hydrophilicity, hydrophobicity, antifogging, abrasion resistance, conductivity, antireflection, antiglare, light diffusion, light scattering, wavelength conversion Moreover, you may provide functions, such as gas-barrier property. In particular, in the case of a solar cell, it is preferable to have an ultraviolet blocking function because it is exposed to strong ultraviolet rays from sunlight. As a method for imparting such a function, a layer having such a function may be formed on a weather-resistant protective sheet by coating film formation or the like, or an additive having such a function is dispersed in a constituent material to provide weather resistance. You may make it contain in a protection sheet.

<Other members: Back protection sheet>
The back surface protection sheet is provided on the back surface opposite to the light receiving surface of the solar cell for the purpose of protection against external stress or the like, and the same sheet or film as the weatherproof protection sheet described above can be used. In addition, if this back surface protection sheet cannot permeate | transmit water and oxygen, it is also possible to make a back surface protection sheet function as a gas barrier layer.

As the material that composes the back protection sheet, it has excellent strength, weather resistance, heat resistance, water resistance, light resistance, etc., and transmits visible light because it is provided on the back side opposite to the light receiving surface. It is also possible to use those that do not transmit visible light, such as polyethylene resins, polypropylene resins, cyclic polyolefin resins, polystyrene resins, acrylonitrile-styrene copolymers (AS resins), and acrylonitrile-butadiene. -Styrene copolymer (ABS resin), polyvinyl chloride resin, fluorine resin, poly (meth) acrylic resin, polycarbonate resin, polyester resin such as polyethylene terephthalate or polyethylene naphthalate, polyamide resin, polyimide resin Resin, polyamideimide resin, polyrelay Sheet or film of resin, silicone resin, polysulfone resin, polyphenylene sulfide resin, polyethersulfone resin, polyurethane resin, acetal resin, cellulosic resin, etc., and one of those materials Or may be formed of two or more materials and used as a single layer film or a laminate film of two or more layers. In the case of a laminated film or the like, surface treatment such as corona treatment or plasma treatment may be performed in order to improve adhesion with other films.

  Among these resins, fluorine-based resins such as polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF), tetrafluoroethylene-ethylene or propylene copolymer (ETFE), and cyclic polyolefins Resins, polycarbonate resins, poly (meth) acrylic resins, polyamide resins, polyester resins and the like are preferable.

Moreover, as a back surface protection sheet, metal materials, such as aluminum foil or a board, a stainless steel thin film, or a steel plate, can also be used, for example, these metals may use 1 type and arbitrary combinations and ratios of 2 or more types. You may use together. In addition, it is preferable that corrosion prevention is given to this metal material.
Furthermore, a composite material of resin and metal can be used. For example, on both surfaces of an aluminum foil, for example, ethylene monofluoride (manufactured by DuPont, trade name “Tedlar”), polytetrafluoroethylene (PTFE), tetrafluoroethylene-ethylene or propylene copolymer (ETFE), fluoride, A highly waterproof sheet in which a film of one or two or more fluorine-based resins such as vinylidene-based resin (PVDF) and vinyl fluoride-based resin (PVF) is bonded may be used.

As thickness of a back surface protection sheet, it is 20 micrometers or more normally, Preferably it is 50 micrometers or more, More preferably, it is 100 micrometers or more. Further, it is usually 1000 μm or less, preferably 500 μm or less, and more preferably 300 μm or less.
In addition, on the back protection sheet, UV blocking, heat blocking, antifouling, hydrophilic, hydrophobic, antifogging, abrasion resistance, conductivity, antireflection, antiglare, light diffusion, light scattering, wavelength conversion, Functions such as gas barrier properties may be imparted. In particular, from the viewpoint of moisture resistance, it is preferable to provide a gas barrier layer by an inorganic oxide vapor deposition layer.

<Method for manufacturing solar cell>
As a manufacturing method of the solar cell of this embodiment, the order of stacking is important. Specifically, a substrate (A), a photoelectric conversion element (B), a layer (C) containing a trapping agent that absorbs moisture and / or oxygen, and a gas barrier layer (D) covering the photoelectric conversion element are sequentially laminated. The photoelectric conversion element (B) is manufactured so as to include a pair of electrodes, an electrode on the side opposite to the substrate (A), and a layer (C) including a trapping agent that absorbs moisture and / or oxygen. 1 layer or multiple layers of anticorrosion layers (E) are laminated.

Preferably, the following manufacturing procedures are mentioned.
Step 1: One or more photoelectric conversion elements (B) are connected in series or in parallel on the substrate (A).
Process 2: The laminated body which laminated | stacked the anticorrosion layer (E) of one layer or multiple layers on the layer (C) containing the capture | acquisition agent which absorbs a water | moisture content and / or oxygen is manufactured.

Step 3: On the photoelectric conversion element (B) on the substrate (A) manufactured in Step 1, a laminate of the layer (C) containing the trapping agent manufactured in Step 2 and the anticorrosion layer (E), and a gas barrier layer The gas barrier film (D) to be stacked is laminated in the order of the substrate (A), the photoelectric conversion element (B), the anticorrosion layer (E), the layer (C) containing the scavenger, and the gas barrier layer (D).
Other preferable production procedures include the following: Step 1: One or more photoelectric conversion elements (B) are connected in series or in parallel on the substrate (A).

Step 2 ′: A laminate in which a gas barrier film (D) to be a gas barrier layer, a layer (C) containing a scavenger that absorbs moisture and / or oxygen, and one or more anticorrosive layers (E) are produced.
Step 3 ′: On the photoelectric conversion element (B) on the substrate (A) manufactured in Step 1, the gas barrier layer (D) manufactured in Step 2 ′, a layer containing a scavenger (C), and an anticorrosion layer (E) Are laminated so as to be in the order of the substrate (A), the photoelectric conversion element (B), the anticorrosion layer (E), the layer (C) containing the scavenger, and the gas barrier layer (D).

  In addition, other members, for example, the above-described sealing material, sealing material, weatherproof protective sheet, back surface protective sheet, etc., are laminated in advance on the substrate (A) and / or the gas barrier film (D) to be the gas barrier layer. After the body is manufactured, the steps 1 to 3 or the steps 1 to 3 ′ may be performed. After the steps 1 to 3 or the steps 1 to 3 ′, the substrate (A) and / or the gas barrier layer may be used. You may laminate | stack on the gas barrier film (D) which becomes.

  At that time, as a preferable stacking order, when the substrate (A) side is a light receiving surface, a weatherproof protective sheet, a gas barrier layer (D), a sealing material, a substrate (A), a photoelectric conversion element (B), an anticorrosion layer ( E), a layer containing a scavenger that absorbs moisture and / or oxygen (C), a gas barrier layer (D), a sealing material, a back surface protective sheet, or a weather resistant protective sheet, a sealing material, a gas barrier layer ( D), substrate (A), photoelectric conversion element (B), anticorrosion layer (E), layer (C) containing a trapping agent that absorbs moisture and / or oxygen, gas barrier layer (D), sealing material, back surface protection The order of the sheets is preferable. On the other hand, when the gas barrier layer (D) is a light receiving surface, a back surface protective sheet, a sealing material, a substrate (A), a photoelectric conversion element (B), an anticorrosion layer (E), a trapping agent that absorbs moisture and / or oxygen. The layer (C) containing gas, the gas barrier layer (D), the sealing material, and the weather-resistant protective sheet are preferable in this order. In addition, the said layer may be laminated | stacked suitably suitably as needed, may be abbreviate | omitted, and another functional layer may be inserted.

  The lamination method is not particularly limited as long as the effects of the present invention are not impaired. For example, an adhesion method using an adhesive, a melt adhesion method using a heating or heating press, an extrusion lamination method, a coextrusion lamination method, a lamination method using a vacuum laminator. Examples thereof include a wet film formation method by coating film formation. Among these, an adhesion method using a photo-curing adhesive having a proven record in organic EL device sealing, a laminating method using a vacuum laminator having a proven record in solar cells, and the like are preferable because general-purpose equipment can be used.

  In addition, although it is preferable to seal the edge part of a solar cell with a sealing material, if the gas barrier property can be maintained, there is no restriction | limiting in particular in the layer to which it adhere | attached. When there are multiple gas barrier layers (D) and substrates (A) and gas barrier layers (D), the gas barrier layer (D) and the substrate (A), and the gas barrier layer (D) and the back surface protection are combined. Examples of the edge of the sheet, the substrate (A) and the weather-resistant protective sheet, any one of the weather-resistant protective sheet and the back-surface protective sheet, a plurality of sets, or all layers. From the viewpoint of emphasizing the maintenance of the gas barrier property, the edge seal of the gas barrier layer (D) and the substrate, the gas barrier layer (D) and the gas barrier layer (D) is preferable, and from the viewpoint of increasing the strength of the entire solar cell, A back protective sheet and all layers are preferred.

The step of sealing the edge with the sealing material at that time can be appropriately selected depending on the layer to be bonded, the type of the sealing material, and the like. For example, the solar cell constituent layer may be sealed after lamination, or may be sealed simultaneously when the constituent layers are laminated. In order to simplify the manufacturing process, it is preferable to seal simultaneously at the time of lamination.
<Performance evaluation of solar cells>
The solar cell according to the present invention is characterized by having the following performance.

For example, in the case of an organic thin film solar cell, performance can be evaluated by performing the following acceleration test and comparing changes in photoelectric conversion characteristics before and after the test.
Accelerated test: An environmental testing machine (for example, “SH-241” manufactured by Espec Corp.) is preferably set in a high-temperature and high-humidity environment of 40 ° C., 90% RH, or 85 ° C., 85% RH. For example, a test specimen is set for 24 hours or longer, and before and after that, a solar simulator is used to measure current / voltage characteristics by irradiating light of AM1.5G with an irradiation intensity of 100 mW / cm ² , and current / voltage obtained from such measurement. From the curve, energy conversion efficiency (PCE), short circuit current, open circuit voltage, FF (fill factor), series resistance, and shunt resistance are obtained.

Examples of the expression for comparing before and after the acceleration test of the photoelectric conversion characteristics include the following expressions.
PCE change rate = (PCE after acceleration test) / (PCE before acceleration test)
The rate of change in energy conversion efficiency (PCE) of the solar cell according to the present invention is usually 0.86 or more after the accelerated test with respect to the initial performance as a value calculated by the above formula, preferably 0.88 or more, more preferably 0.90 or more.

The solar cell according to the present invention does not contact the layer (C) containing the scavenger and the device electrode even when a load is applied, and has a high performance of preventing deterioration. As the evaluation, the presence or absence of contact when the layer (C) containing the scavenger is pressed in the photoelectric conversion element (B) direction from the gas barrier layer (D) side may be confirmed.
Moreover, the solar cell according to the present invention has good weather resistance. Even if a weather resistance test is performed using an outdoor exposure test or a weather resistance tester, the initial performance is maintained and high durability performance is exhibited. This is considered to be because electrode deterioration is suppressed by the presence of the anticorrosion layer, and when the weatherproof protective sheet is laminated, higher durability performance can be exhibited.

Synthesis Example 1 Synthesis Example of Phosphine Oxide Compound 1 [F-POPy ₂ ]
As shown in the following formula, 5.6 g (20 mmol) of 1-bromopyrene (manufactured by Tokyo Chemical Industry Co., Ltd.) was dissolved in 100 mL of dehydrated tetrahydrofuran (manufactured by Kanto Chemical Co., Ltd.) under a nitrogen atmosphere, cooled to −78 ° C., and then n-butyl. Lithium (manufactured by Kanto Chemical Co., Inc.) 13 mL (1.6 M) was slowly added dropwise and stirred for 45 minutes while maintaining -78 ° C. Subsequently, 3.1 g (10 mmol) of triphenyl phosphite (manufactured by Wako Pure Chemical Industries, Ltd.) was added dropwise, and after sufficient stirring, the temperature was raised to room temperature, stirred for 1.5 hours, and cooled again to -78 ° C. . On the other hand, 3.5 g (20 mmol) of 4-fluorobromobenzene (manufactured by Tokyo Chemical Industry Co., Ltd.) was dissolved in 50 mL of dehydrated tetrahydrofuran in another reaction vessel, and n-butyllithium (Kanto Chemical Co., Ltd.) at -78 ° C. in a nitrogen atmosphere. 13 mL (1.6M) was added and stirred for 30 minutes, then dropped in the first container, warmed to room temperature, and stirred for 1 hour. 20 mL of water was added to the obtained reaction solution, tetrahydrofuran was distilled off under reduced pressure, and extraction was performed using methylene chloride. The organic layer was dried by adding magnesium sulfate, concentrated by filtration, and purified using column chromatography (developing solvent hexane) to obtain 3.7 g of the target precursor (F-PPy ₂ ). The compound obtained here is acetone (
It was dissolved in 150 mL of Kanto Chemical Co., Ltd., 2 mL of 30% hydrogen peroxide solution (Wako Pure Chemical Industries, Ltd.) was added, and the mixture was stirred at room temperature. 20 mL of water was added to the reaction solution, concentrated, and then washed with acetonitrile to obtain 1.9 g of the desired product. The obtained phosphine oxide compound 1 is referred to as “F-POPy ₂ ”.

Synthesis Example 2 Synthesis Example of Phosphine Oxide Compound 2 [CF ₃ -POPy ₂ ]

In a nitrogen atmosphere, 1-bromopyrene (Tokyo Kasei: 5.6 g, 20 mmol) was dissolved in dehydrated THF (Kanto Chemical: 100 mL), cooled to −78 ° C., and then n-BuLi (Kanto Chemical: 13 mL, 1.6 M). Was slowly added dropwise and stirred for 45 minutes while maintaining -78 ° C. Subsequently, triphenyl phosphite (Wako Pure Chemical: 3.1 g, 10 mmol) was added dropwise, and after sufficient stirring, the temperature was raised to room temperature, stirred for 1.5 h, and then cooled to -78 ° C again. On the other hand, 4-trifluoromethyl bromobenzene (Tokyo Kasei: 4.4 g, 20 mmol) was dissolved in dehydrated THF (50 mL) in another reaction vessel, and n-BuLi (Kanto) at -78 ° C. in a nitrogen atmosphere. Chemistry: 13 mL, 1.6 M) was added, and the mixture was stirred for 30 minutes, then dropped in the first container, warmed to room temperature, and stirred for 1 hour. 20 mL of water was added to the obtained reaction solution, THF was distilled off under reduced pressure, and extraction was performed using methylene chloride. The organic layer is dried by adding magnesium sulfate, concentrated by filtration, and purified by column chromatography (developing solvent: Hexane) to obtain 2.9 g (yield 50%) of the target precursor (CF ₃ − PP
y ₂₎ was obtained. The compound was identified using NMR.

2.9 g of the compound obtained above was dissolved in acetone (Kanto Chemical: 150 mL), hydrogen peroxide (Wako Pure Chemicals: 2% of 30% solution) was added, and the mixture was stirred at room temperature. The reaction solution was added with 20 mL of water, concentrated, and washed with acetonitrile to obtain 2.4 g (yield 80%) of the target product (CF ₃ -POPy ₂ ). The resulting product was confirmed by NMR.
Synthesis Example 3 Synthesis Example of Phosphine Oxide Compound 3 [(CF ₃ ) ₂ -POPy ₂ ]

  In a nitrogen atmosphere, 1-bromopyrene (Tokyo Kasei: 5.6 g, 20 mmol) was dissolved in dehydrated THF (Kanto Chemical: 100 mL), cooled to −78 ° C., and then n-BuLi (Kanto Chemical: 13 mL, 1.6 M). Was slowly added dropwise and stirred for 30 minutes while maintaining -78 ° C. Subsequently, triphenyl phosphite (Wako Pure Chemicals: 3.1 g, 10 mmol) was added dropwise, and after sufficient stirring, the temperature was raised to room temperature, stirred for 1.5 hours, and then cooled to -78 ° C again. On the other hand, 3,5-bistrifluoromethylbromobenzene (Tokyo Kasei: 5.8 g, 20 mmol) was dissolved in dehydrated THF (50 mL) in a separate reaction vessel, and in a nitrogen atmosphere at −78 ° C., n-BuLi. (Kanto Chemical Co., Inc .: 13 mL, 1.6 M) was added, and the mixture was stirred for 30 minutes, then dropped in the first container, warmed to room temperature, and stirred for 12 hours. 20 mL of water was added to the obtained reaction solution, THF was distilled off under reduced pressure, and extraction was performed using dichloromethane. The organic layer was dried by adding magnesium sulfate, concentrated by filtration, and purified by column chromatography (developing solvent: mixed solvent of Hexane and dichloromethane) to obtain 0.9 g of a target product precursor. The compound was identified using NMR.

0.9 g of the compound obtained above was dissolved in dichloromethane (Kanto Chemical: 100 mL), hydrogen peroxide solution (Wako Pure Chemicals: 2% of 30% solution) was added, and the mixture was stirred at room temperature. 20 mL of water was added to the reaction solution, followed by extraction and drying using sodium sulfate, and the solvent was removed by distillation under reduced pressure. The suspension was washed with hexane and methanol to obtain 0.6 g (yield 9%) of the desired product ((CF ₃ ) ₂ -POPy ₂ ). The resulting product was confirmed by NMR.

Synthesis Example 4 Synthesis Example of Phosphine Oxide Compound 4 [(FPh) ₂ -POPy]

Under a nitrogen atmosphere, 2.0 g (7.1 mmol) of 1-bromopyrene (Tokyo Kasei Co., Ltd.) was dissolved in 30 mL of dehydrated tetrahydrofuran (manufactured by Kanto Chemical Co., Inc.), cooled to -78 ° C, and then n-butyllithium (Kanto Chemical Co., Ltd.). (Manufactured) 5.3 mL (1.6 M) was slowly added dropwise, and the mixture was stirred for 1 hour while maintaining -78 ° C. Subsequently, 2.0 g (7.8 mmol) of chlorobis (4-fluorophenyl) phosphine was added dropwise and stirred sufficiently, and then the temperature was raised to room temperature and stirred for 1.5 hours. After quenching with water, THF was removed by distillation under reduced pressure, 10 mL of dichloromethane and 5 mL of 30% hydrogen peroxide were added and stirred for 30 minutes. After washing with Brine, drying over magnesium sulfate, removing dichloromethane by distillation under reduced pressure, and purifying by GPC, the desired product ((FPh) ₂ -POPy) was obtained.

Synthesis Example 5 Synthesis Example of Phosphine Oxide Compound 5 [POPy ₂ ]
As shown in the following formula, 14 g (50 mmol) of 1-bromopyrene (manufactured by Tokyo Chemical Industry Co., Ltd.) was dissolved in 200 mL of dehydrated tetrahydrofuran (manufactured by Kanto Chemical Co., Ltd.) in a nitrogen atmosphere, cooled to −78 ° C., and then n-butyllithium ( 33 mL (1.6 M) (manufactured by Kanto Chemical Co., Inc.) was slowly added dropwise, and the mixture was stirred for 30 minutes while maintaining -78 ° C. Subsequently, 4.3 g (9.0 mmol) of dichlorophenylphosphine (manufactured by Tokyo Chemical Industry Co., Ltd.) was added dropwise and stirred sufficiently, and then the temperature was raised to room temperature and stirred for 1.5 hours. 30 mL of methanol (manufactured by Junsei Co., Ltd.) was added to the obtained reaction solution, and the obtained crude product was filtered and recrystallized using benzene to obtain 10.7 g of the desired product. The compound obtained here was dissolved in 350 mL of tetrahydrofuran (manufactured by Junsei Chemical Co., Ltd.), 300 mL of methylene chloride (manufactured by Kanto Chemical Co., Ltd.) and 100 mL of acetone (manufactured by Kanto Chemical Co., Ltd.), and 30% hydrogen peroxide solution (manufactured by Wako Pure Chemical Industries, Ltd.) 10 mL was added and stirred at room temperature for 30 minutes.

The reaction solution was added with 30 mL of water, concentrated to 600 mL, and then filtered to obtain 7.5 g of the desired product. The obtained phosphine oxide compound 5 is referred to as “POPy ₂ ”.

  Synthesis Example 6 Synthesis Example of Fullerene Compound 1 [SIMEF]

The synthesis of SIMEF was performed by the method described in International Publication WO2009 / 008323 Pamphlet.
<Example 1>
Poly (3,4-ethylenedioxythiophene) poly (styrenesulfonic acid) aqueous dispersion (HCL Starck Co., Ltd. “CLEVIOS ^™ PVP AI4083” as a hole extraction layer on a glass substrate on which an ITO electrode is patterned ) Was applied by spin coating, and then the substrate was subjected to heat treatment on a hot plate at 120 ° C. for 10 minutes in the air. The film thickness was about 30 nm.

  On the other hand, tetrabenzoporphyrin (compound A) represented by the following formula (A) is put into a metal boat arranged in a vacuum deposition apparatus, vacuum-deposited on the substrate obtained above, and then in a nitrogen atmosphere. The substrate was heat treated at 180 ° C. for 20 minutes to form a p-type semiconductor layer having a thickness of about 25 nm on the hole extraction layer.

  Subsequently, 0.6 wt% of polyphyllin having a bicyclo ring structure (compound B) represented by the following formula (B) was obtained in Synthesis Example 6 in a 1: 1 mixed solvent (weight) of chloroform / monochlorobenzene. A liquid in which 1.4% by weight of the obtained fullerene compound 1 (SIMEF) was dissolved was prepared and filtered, and the obtained filtrate was spun at 1500 rpm in a nitrogen atmosphere on the p-type semiconductor layer obtained above. Coated and heated at 180 ° C. for 20 minutes. Thus, a mixture layer containing tetrabenzoporphyrin (compound A) and a fullerene compound was formed on the p-type semiconductor layer obtained above.

  Next, a solution in which 1.2% by weight of fullerene compound 1 (SIMEF) obtained in Synthesis Example 6 was dissolved in toluene was prepared and filtered, and the obtained filtrate was placed on the mixture layer obtained above. It spin-coated at 3000 rpm in nitrogen atmosphere, and heat-processed at 120 degreeC for 5 minute (s). Thus, a fullerene compound 1 (SIMEF) layer was formed on the mixture layer containing tetrabenzoporphyrin (compound A) and fullerene compound 1 (SIMEF).

Subsequently, “F-POPy ₂ ” obtained in Synthesis Example 1 is placed in a metal boat placed in a vacuum evaporation apparatus and heated to a film thickness of 6 nm on the fullerene compound layer obtained above. The electron extraction layer was formed on one fullerene compound layer.
Furthermore, an aluminum electrode having a thickness of 80 nm was provided on the obtained electron extraction layer by vacuum vapor deposition, and then heated on a hot plate at 120 ° C. for 10 minutes to produce a solar cell.

The produced solar cell was irradiated with light of 100 mW / cm ² with a solar simulator (AM1.5G) from the ITO electrode side, and between the ITO electrode and the aluminum electrode with a source meter (Type 2400 manufactured by Keithley). The current-voltage characteristics were measured and the results are shown in Table 1.
<Example 2>
Instead of “F-POPy ₂ ” used as the electron extraction layer in Example 1, Synthesis Example 2
120 after using the “CF ₃ -POPy ₂ ” obtained in step ₁ and providing the aluminum electrode.
A solar cell was produced in the same manner except that it was heated at 5 ° C. for 5 minutes. About the obtained solar cell, it carried out similarly to Example 1, and measured the current-voltage characteristic, and Table 1 shows the result.

<Example 3>
In place of “F-POPy ₂ ” used as the electron extraction layer in Example 1, “(CF ₃ ) ₂ -POPy ₂ ” obtained in Synthesis Example 3 was used, and after the aluminum electrode was provided, 120 ° C. A solar cell was produced in the same manner except that it was heated for 5 minutes. About the obtained solar cell, it carried out similarly to Example 1, and measured the current-voltage characteristic, and Table 1 shows the result.

<Example 4>
As in Example 1, four layers up to the fullerene compound (SIMEF) layer were formed on the substrate. Next, 5.0 mg of “(FPh) ₂ POPy” obtained in Synthesis Example 4 was dissolved in isopropanol while stirring at room temperature for 30 minutes to prepare 0.05 wt% ink. The ink was spin coated at 3000 rpm and heated at 80 ° C. for 5 minutes. Thus, a buffer layer of about 6 nm was formed on the fullerene compound (SIMEF) layer. Further, an aluminum electrode having a thickness of 80 nm was provided on the buffer layer by vacuum deposition, and then this solar cell was heated on a hot plate at 120 ° C. for 5 minutes to produce a solar cell. About the obtained solar cell, it carried out similarly to Example 1, and measured the current-voltage characteristic, and Table 1 shows the result.

<Comparative Example 1>
A solar cell was produced in the same manner except that “POPy ₂ ” obtained in Synthesis Example 5 was used instead of “F-POPy ₂ ” used as the electron extraction layer in Example 1. With respect to the obtained solar cell, current-voltage characteristics were measured in the same manner as in Example 1, and the results are shown in Table 1.

<Comparative example 2>
A solar cell was produced in the same manner except that the compound “BCP” represented by the following formula was used instead of “F-POPy ₂ ” used as the electron extraction layer in Example 1. With respect to the obtained solar cell, current-voltage characteristics were measured in the same manner as in Example 1, and the results are shown in Table 1.

<Comparative Example 3>
A solar cell was produced in the same manner as in Example 1 except that the electron extraction layer was not provided and the aluminum electrode was provided but not heated. With respect to the obtained solar cell, current-voltage characteristics were measured in the same manner as in Example 1, and the results are shown in Table 1.

<Example 5>
Regioregular poly-3-hexylthiophene (P3HT) (manufactured by Aldrich) having an electron-donating molecular structure, and 1- (3-methoxycarbonyl) propyl-1-phenyl (6,6) having an electron-accepting molecular structure -C ₆₀ (C ₆₀ (PCBM), manufactured by Frontier Carbon Co., Ltd.) was dissolved in o-dichlorobenzene at a concentration of 2.1% by weight at a weight ratio of 1: 0.8. The resulting solution was stirred and mixed with a stirrer at 40 ° C. in a nitrogen atmosphere for 4 hours, and then filtered through a 0.45 μm polytetrafluoroethylene filter to prepare a photoelectric conversion layer coating solution.

A glass substrate on which an indium tin oxide (ITO) transparent conductive film with a thickness of 155 nm is deposited is cleaned in the order of ultrasonic cleaning with a surfactant, water with ultrapure water, and ultrasonic cleaning with ultrapure water, followed by nitrogen blowing. And dried by heating at 120 ° C. in the air for 5 minutes, and finally, ultraviolet ozone cleaning was performed.
On this transparent substrate, an aqueous dispersion of poly (3,4-ethylenedioxythiophene) poly (styrenesulfonic acid) filtered through a 0.45 μm polyvinylidene fluoride filter (“CLEVIO ^™ PVP AI4083 manufactured by H.C. Starck Co., Ltd.) After spin coating, the substrate was heat-dried at 120 ° C. for 10 minutes in the air, and the substrate was further heat-treated at 180 ° C. for 3 minutes in a nitrogen atmosphere. The film thickness was 60 nm.

On the glass substrate obtained above, the photoelectric conversion layer coating solution is applied by spin coating in a nitrogen atmosphere to form an active layer having a thickness of 200 nm, and an annealing treatment is performed at 150 ° C. for 10 minutes in a nitrogen atmosphere. went. Thereafter, the “F-POPy ₂ ” having a thickness of 5 nm as a buffer layer and aluminum having a thickness of 80 nm are sequentially formed by resistance heating vacuum deposition, and a 5 mm square bulk heterojunction organic thin film solar cell is formed. Was made.

Using a solar simulator with air mass (AM) 1.5 and irradiance of 100 mW / cm ² as the irradiation light source, the current-voltage characteristics of the produced solar cell were measured with a 4 mm square metal by a source meter (Type 2400 manufactured by Keithley). Evaluation was performed with a mask attached, and the results are shown in Table 2.
<Comparative example 4>
Bulk heterojunction was similarly performed except that “POPy ₂ ” obtained in Synthesis Example 5 was used instead of “F-POPy ₂ ” used as the buffer layer in Example 5, and the film thickness was changed to 6 nm. Type organic thin film solar cell was produced. For the obtained solar cell, current-voltage characteristics were measured in the same manner as in Example 2, and the results are shown in Table 2.

  From the results shown in Tables 1 and 2, it was found that the photoelectric conversion element containing the compound of the present invention as an electrode buffer material is suitable as a photoelectric conversion element for solar cell applications having excellent battery characteristics.

  The photoelectric conversion element material comprising the phosphine oxide or phosphine sulfide compound of the present invention is useful as an electrode buffer material having excellent interaction with an electrode and high performance, and is suitable for use in a photoelectric conversion element.

DESCRIPTION OF SYMBOLS 100 Substrate 101 Transparent electrode 102 Electrode buffer layer 103 P-type semiconductor 104 P-type semiconductor, n-type semiconductor mixed layer 105 N-type semiconductor 106 Electrode buffer layer 107 Counter electrode

Claims (3)

A photoelectric conversion element having at least an active layer and an electrode buffer layer between a pair of electrodes, wherein the electrode buffer layer contains an electrode buffer material made of a phosphine oxide or phosphine sulfide compound represented by the following general formula (1) Photoelectric conversion element.
[In the formula (1), Ar ¹ represents an acenaphthylene ring, phenanthrene ring, anthracene ring, triphenylene ring, pyrene ring, chrysene ring, perylene ring, dibenzofuran ring, xanthene ring, carbazole ring, quinoline ring, isoquinoline ring, acridine ring, Represents a nanthridine ring, a phenanthroline ring, a quinoxaline ring, a dibenzothiophene ring, or a phenoxazine ring , Ar ² represents a monocyclic aromatic group, A represents a fluorine atom or a perfluoroalkyl group, and X represents an oxygen atom or Represents a sulfur atom. m is an integer of 1 to 3, n is an integer of 1 to 5, and p is an integer of 1 or more. However, when m is 3, p is 1. ] A solar cell comprising the photoelectric conversion element according to claim 1 . It is a manufacturing method of the photoelectric conversion element of Claim 1 , Comprising: The said buffer layer is formed by the wet apply | coating method, The manufacturing method of the photoelectric conversion element characterized by the above-mentioned.