JP5851268B2 - Material for organic thin film solar cell element and organic thin film solar cell using the same - Google Patents

Description

  The present invention relates to an organic thin film solar cell element material and an organic thin film solar cell using the same.

  An organic thin film solar cell is a device that shows an electrical output with respect to an optical input, as represented by a photodiode or an imaging device that converts an optical signal into an electrical signal, or a solar cell that converts optical energy into electrical energy, It is a device that exhibits a response opposite to that of an electroluminescence (EL) element that exhibits an optical output with respect to an electrical input. In particular, solar cells have attracted a great deal of attention as a clean energy source in recent years against the background of fossil fuel depletion and global warming, and research and development have been actively conducted.

Organic thin-film solar cells have been studied with a single-layer film using a merocyanine dye, etc., but a multilayer film of p layer (layer transporting holes) / n layer (layer transporting electrons) is used. Since it has been found that the conversion efficiency is improved, multilayer films have become mainstream. The materials used at this time were copper phthalocyanine (CuPc) for the p layer and peryleneimides (PTCBI) for the n layer.
Subsequently, it has been found that the conversion efficiency is improved by inserting an i layer (a mixed layer of p material and n material) between the p layer and the n layer to increase the number of layers. However, the materials used at this time were still phthalocyanines and peryleneimides. Thereafter, it was found that the conversion efficiency was further improved by a stack cell structure in which a number of p / i / n layers were stacked. The material system at this time was phthalocyanines and C60 fullerene.

  In an organic thin film solar cell using a polymer, a conductive polymer is used as a p material, a C60 derivative is mixed as an n material, and they are mixed and heat-treated to induce microlayer separation to increase the heterointerface, Research on so-called bulk heterostructures that improve the conversion efficiency has been mainly conducted. The material system used here was mainly a soluble polythiophene derivative called P3HT as the p material and a soluble C60 derivative called PCBM as the n material.

  Thus, in organic thin film solar cells, conversion efficiency has been improved by optimizing the cell configuration and morphology, but the material system used there has not made much progress since the early days, and phthalocyanines, peryleneimides still remain. Class C60 has been used. Therefore, development of a new material system to replace them has been eagerly desired.

  Patent Documents 1 and 2 disclose a compound having a pyromethene skeleton as an organic solar cell material, but none of them has high performance. Patent Document 1 shows a high open-circuit voltage (Voc) by using a compound having a pyromethene skeleton as an n-type material, but there is no disclosure of conversion efficiency, and the material disclosed in Patent Document 2 is a dye-sensitized solar cell. The conversion efficiency of the resulting battery was not sufficient at 0.02%.

JP 2008-109097 A JP 2010-184880 A

  The objective of this invention is providing the organic thin-film solar cell element material from which a highly efficient photoelectric conversion characteristic is obtained, and an organic thin-film solar cell using the same.

（式中、Ｒ^０〜Ｒ^４は、それぞれ独立に、水素原子、置換若しくは無置換の炭素数１〜２０のアルキル基、置換若しくは無置換の環形成炭素数６〜２０のアリール基、又は置換若しくは無置換の環形成原子数５〜２０の複素環基であり、Ｒ^０〜Ｒ^４のうち隣接するものは、互いに結合して環を形成してもよい。
Ｘは、それぞれ独立に、ハロゲン原子又はアルコキシ基である。）
２．前記式（１）の２つのＸがフッ素原子である１に記載の有機薄膜太陽電池素子用材料。
３．前記式（１）で表される化合物が、下記式（２）で表わされる化合物又は下記式（３）で表わされる化合物である１又は２に記載の有機薄膜太陽電池素子用材料。

４．前記式（１）〜（３）のいずれかで表される化合物が、ｐ層又はｉ層に用いられる１〜３のいずれかに記載の有機薄膜太陽電池素子用材料。
５．一対の電極間に１以上の有機薄膜層を備える有機薄膜太陽電池であって、前記有機薄膜層の少なくとも一層が、下記式（１）で表される化合物を含む有機薄膜太陽電池。

（式中、Ｒ^０〜Ｒ^４は、それぞれ独立に、水素原子、置換若しくは無置換の炭素数１〜２０のアルキル基、置換若しくは無置換の環形成炭素数６〜２０のアリール基、又は置換若しくは無置換の環形成原子数５〜２０の複素環基であり、Ｒ^０〜Ｒ^４のうち隣接するものは、互いに結合して環を形成してもよい。
Ｘは、それぞれ独立に、ハロゲン原子又はアルコキシ基である。）
６．前記式（１）の２つのＸがフッ素原子である５に記載の有機薄膜太陽電池。
７．前記式（１）で表される化合物が、下記式（２）で表わされる化合物又は下記式（３）で表わされる化合物である５又は６に記載の有機薄膜太陽電池。

８．前記１以上の有機薄膜層がｐ層、ｉ層、ｎ層のいずれかであって、前記ｐ層及び／又は前記ｉ層に、前記式（１）〜（３）のいずれかで表される化合物を含む５〜７のいずれかに記載の有機薄膜太陽電池。
９．前記ｎ層及び／又は前記ｉ層が、フラーレン又はフラーレン誘導体をさらに含む８に記載の有機薄膜太陽電池。
１０．５〜９のいずれかに記載の有機薄膜太陽電池を具備する装置。 According to the present invention, the following materials for organic thin film solar cell elements and the like are provided.
1. The material for organic thin-film solar cell elements containing the compound represented by following formula (1).

(In the formula, R ^{0 to} R ⁴ are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 20 ring carbon atoms, or a substituted group. Alternatively, it is an unsubstituted heterocyclic group having 5 to 20 ring atoms, and adjacent ones of R ^{0 to} R ⁴ may be bonded to each other to form a ring.
X is each independently a halogen atom or an alkoxy group. )
2. 2. The material for an organic thin-film solar cell element according to 1, wherein two Xs in the formula (1) are fluorine atoms.
3. The organic thin-film solar cell element material according to 1 or 2, wherein the compound represented by the formula (1) is a compound represented by the following formula (2) or a compound represented by the following formula (3).

4). The organic thin-film solar cell element material according to any one of 1 to 3, wherein the compound represented by any one of the formulas (1) to (3) is used for the p layer or the i layer.
5. An organic thin-film solar battery comprising one or more organic thin-film layers between a pair of electrodes, wherein at least one of the organic thin-film layers contains a compound represented by the following formula (1).

(In the formula, R ^{0 to} R ⁴ are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 20 ring carbon atoms, or a substituted group. Alternatively, it is an unsubstituted heterocyclic group having 5 to 20 ring atoms, and adjacent ones of R ^{0 to} R ⁴ may be bonded to each other to form a ring.
X is each independently a halogen atom or an alkoxy group. )
6). 6. The organic thin-film solar cell according to 5, wherein two Xs in the formula (1) are fluorine atoms.
7). The organic thin film solar cell according to 5 or 6, wherein the compound represented by the formula (1) is a compound represented by the following formula (2) or a compound represented by the following formula (3).

8). The one or more organic thin film layers are any one of a p layer, an i layer, and an n layer, and the p layer and / or the i layer are represented by any one of the formulas (1) to (3). The organic thin-film solar cell in any one of 5-7 containing a compound.
9. 9. The organic thin-film solar cell according to 8, wherein the n layer and / or the i layer further contains fullerene or a fullerene derivative.
The apparatus which comprises the organic thin-film solar cell in any one of 10.5-9.

  ADVANTAGE OF THE INVENTION According to this invention, the organic solar cell using the material for organic thin-film solar cell elements from which a highly efficient photoelectric conversion characteristic is obtained can be provided.

（式中、Ｒ^０〜Ｒ^４は、それぞれ独立に、水素原子、置換若しくは無置換の炭素数１〜２０のアルキル基、置換若しくは無置換の環形成炭素数６〜２０のアリール基、又は置換若しくは無置換の環形成原子数５〜２０の複素環基であり、Ｒ^０〜Ｒ^４のうち隣接するものは、互いに結合して環を形成してもよい。
Ｘは、それぞれ独立に、ハロゲン原子又はアルコキシ基であり、好ましくは２つのＸがフッ素原子である） [Materials for organic thin-film solar cell elements]
The organic thin film solar cell element material of the present invention contains a compound represented by the following formula (1).

(In the formula, R ^{0 to} R ⁴ are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 20 ring carbon atoms, or a substituted group. Alternatively, it is an unsubstituted heterocyclic group having 5 to 20 ring atoms, and adjacent ones of R ^{0 to} R ⁴ may be bonded to each other to form a ring.
X is independently a halogen atom or an alkoxy group, and preferably two Xs are fluorine atoms)

（式中、Ｒ^０〜Ｒ^４及びＸは式（１）と同様である。） The compound represented by the formula (1) (hereinafter sometimes simply referred to as the compound of the present invention) is a compound having a pyromethene skeleton, and in particular, when R ⁵ and R ⁶ of the compound shown below are hydrogen atoms. There is no steric hindrance with X on boron, and it can have high molecular flatness. By having high molecular planarity, the short circuit current (Jsc) can be improved and the conversion efficiency can be improved.
For example, when R ⁵ and R ⁶ are an aromatic ring group and / or a heterocyclic group, the aromatic ring group and / or heterocyclic group of R ⁵ and R ⁶ is , It is arranged perpendicular to the pyromethene skeleton and the molecular planarity is lost.

(In the formula, R ^{0 to} R ⁴ and X are the same as in formula (1).)

Hereafter, each substituent of the compound of this invention is demonstrated.
As the alkyl group having 1 to 20 carbon atoms of R ^{0 to} R ^4, the alkyl moiety preferably has 1 to 8 carbon atoms, and the alkyl moiety may be linear, branched or cyclic, Methyl group, ethyl group, 1-propyl group, 2-propyl group, 1-butyl group, 2-butyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group, octyl group, decyl group, dodecyl group , 2-ethylhexyl group, 3,7-dimethyloctyl group, cyclopropyl group, cyclopentyl group, cyclohexyl group, 1-adamantyl group, 2-adamantyl group, norbornyl group and the like. Of these, a methyl group, an ethyl group, a 1-propyl group, a 2-propyl group, a tert-butyl group, a pentyl group, and a cyclohexyl group are more preferable from the viewpoint of availability of raw materials.
Examples of the substituent of the alkyl group include a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, and an aryl group such as a phenyl group, and the aryl group includes a methyl group, an ethyl group, a propyl group and the like. The alkyl group having 1 to 5 carbon atoms may be further substituted.
Examples of the substituted alkyl group include trifluoromethyl group, trichloromethyl group, benzyl group, α, α-dimethylbenzyl group, 2-phenylethyl group, and 1-phenylethyl group.

Examples of the aryl group having 6 to 20 ring carbon atoms of R ^{0 to} R ⁴ include a phenyl group, 2-tolyl group, 4-tolyl group, 4-trifluoromethylphenyl group, 4-methoxyphenyl group, 4- Cyanophenyl group, 2-biphenylyl group, 3-biphenylyl group, 4-biphenylyl group, terphenylyl group, 3,5-diphenylphenyl group, 3,4-diphenylphenyl group, pentaphenylphenyl group, 4- (2,2- Diphenylvinyl) phenyl group, 4- (1,2,2-triphenylvinyl) phenyl group, fluorenyl group, 1-naphthyl group, 2-naphthyl group, 2- (1,4-diphenyl) naphthyl group, 9-anthryl Group, 2-anthryl group, 2- (1,4-diphenyl) anthryl group), 2- (9,10-diphenyl) anthryl group, 9-phenanthryl. , 1-pyrenyl group, chrysenyl group, naphthacenyl group, coronyl group, and the like. Of these, a phenyl group, a 4-biphenylyl group, a 1-naphthyl group, a 2-naphthyl group, a 2-anthryl group, a 9-phenanthryl group, and the like are more preferable from the viewpoint of availability of raw materials.
Examples of the substituent for the aryl group include halogen atoms such as fluorine atom, chlorine atom, bromine atom and iodine atom, alkyl groups having 1 to 5 carbon atoms such as methyl group, ethyl group and propyl group, methoxy group and ethoxy group. Group, an alkoxy group having 1 to 5 carbon atoms such as a propoxy group, an aryl group such as a cyano group and a phenyl group, a heterocyclic ring such as carbazole, and an arylamino group such as a diphenylamino group.

The heterocyclic group having 5 to 20 ring atoms of R ^{0 to} R ⁴ is preferably a heterocyclic group having 5 to 15 ring atoms, such as furan, thiophene, pyrrole, imidazole, benzimidazole, pyrazole, Examples include groups formed from benzpyrazole, triazole, oxadiazole, pyridine, pyrazine, triazine, quinoline, benzofuran, dibenzofuran, benzothiophene, dibenzothiophene and carbazole. Of these, furan, thiophene, bithiophene, terthiophene, pyridine, carbazole and the like are preferable from the viewpoint of availability of raw materials.
Examples of the substituent of the heterocyclic ring include halogen atoms such as fluorine atom, chlorine atom, bromine atom and iodine atom, alkyl groups having 1 to 5 carbon atoms such as methyl group, ethyl group and propyl group, thiophene group and dicyano. A vinyl group is mentioned.

X is a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom or an iodine atom, or an alkoxy group. The alkoxy group for X is, for example, an alkoxy group containing an alkyl moiety having 1 to 20 carbon atoms, preferably the alkyl moiety has 1 to 8 carbon atoms, and the alkyl moiety is linear, branched or cyclic. There may be. Specifically, the alkyl moiety is a methyl group, ethyl group, 1-propyl group, 2-propyl group, 1-butyl group, 2-butyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group, Octyl group, decyl group, dodecyl group, 2-ethylhexyl group, 3,7-dimethyloctyl group, cyclopropyl group, cyclopentyl group, cyclohexyl group, 1-adamantyl group, 2-adamantyl group, norbornyl group, trifluoromethyl group, Examples include alkoxy groups such as 2,3-perfluoropropyl, trichloromethyl group, benzyl group, α, α-dimethylbenzyl group, 2-phenylethyl group, 1-phenylethyl group and the like. Among these, an alkoxy group in which the alkyl portion is a methyl group, an ethyl group, or a 1-propyl group is more preferable from the viewpoint of availability of raw materials.
The alkyl moiety may be substituted. Examples of the substituent include a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, and an aryl group such as a phenyl group, and the aryl group is a methyl group. , May be further substituted with an alkyl group having 1 to 5 carbon atoms such as an ethyl group or a propyl group.

In the present invention, the hydrogen atom includes light hydrogen, deuterium, and tritium. For example, when R ⁰ is a hydrogen atom, it may be light hydrogen, deuterium, or tritium.

Specific examples of the compound for organic thin film solar cell element of the present invention are shown below.
In addition, the compound represented by Formula (1) is not limited to the following compound.

Among the above specific examples, a compound represented by the following formula (2) which is the compound 3 of the specific example or a compound represented by the following formula (3) which is the compound 10 of the specific example is more preferable.

  The compounds of the present invention are described, for example, in Synthetic. Communications, 29 (19), 3353 (1999), Inorg. Chem. , 42, 6629 (2003), J. Am. Org. Chem. 64, 7813 (1999), Org. Lett., 13 (12), 2992 (2010). For example, a method in which two pyrrole derivatives are condensed with an aldehyde derivative, oxidized and reacted with a boron derivative, or further brominated and a substituent is introduced using a catalyst such as Pd.

  The organic thin-film solar cell element material of the present invention may contain the compound of the present invention and may consist only of the compound of the present invention.

The organic thin film solar cell material of the present invention is suitable as a material of an active layer of an organic thin film solar cell, and particularly suitable as a material of a p layer or an i layer (a mixed layer of p material and n material).
The characteristics required for the material of the p layer (p material) are such that the absorption intensity in the desired wavelength region is large and the charge after charge separation can be efficiently transported to the positive electrode and the negative electrode. In particular, in order to construct a hole conduction path, it is important to use a compound having high planarity so that the compounds can easily approach each other.
Since the compound of the present invention has high flatness as described above, the use of the organic thin film solar cell material of the present invention increases the short-circuit current (Jsc) of the organic thin film solar cell and increases the photoelectric conversion efficiency. Can do.

[Organic thin film solar cells]
The cell structure of the organic thin film solar cell of the present invention is not particularly limited as long as it has a layer containing the above compound between a pair of electrodes. Specifically, a structure having the following configuration on a stable insulating substrate can be given.
(1) Lower electrode / organic thin film layer / upper electrode (2) Lower electrode / p layer / n layer / upper electrode (3) Lower electrode / p layer / i layer (or a mixed layer of p and n materials) / n Layer / upper electrode (4) Lower electrode / mixed layer of p material and n material / upper electrode In the above configurations (2) and (3), the p layer and the n layer may be replaced.

Moreover, you may provide a buffer layer between an electrode and an organic layer as needed. For example, as a specific example, when a buffer layer is provided in the configuration (1), a structure having the following configuration can be given.
(5) Lower electrode / buffer layer / p layer / n layer / upper electrode (6) Lower electrode / p layer / n layer / buffer layer / upper electrode (7) Lower electrode / buffer layer / p layer / n layer / buffer Layer / Top electrode

The organic thin film solar cell element material of the present invention can be used for a buffer layer in addition to an active layer such as a p layer, an n layer, and an i layer.
The organic thin film solar cell of this invention should just contain the organic thin film solar cell element material of this invention in any member which comprises a battery. Moreover, the member of the organic thin film solar cell of the present invention may be formed only from the organic thin film solar cell element material, or may be formed from a mixture of the organic thin film solar cell element material and other components. Also good. About the member and mixed material which do not contain the material of this invention, the well-known member and material used with an organic thin film solar cell can be used.
Hereinafter, each component will be briefly described.

1. Lower electrode, upper electrode The material of the lower electrode and the upper electrode is not particularly limited, and a known conductive material can be used. For example, a metal such as tin-doped indium oxide (ITO), gold (Au), osmium (Os), palladium (Pd) can be used as the electrode connected to the p layer, and silver as the electrode connected to the n layer. Metals such as (Ag), aluminum (Al), indium (In), calcium (Ca), platinum (Pt), lithium (Li) and the like, and binary metal systems such as Mg: Ag, Mg: In and Al: Li, Furthermore, the electrode example material connected with the said P layer can be used.
In order to obtain highly efficient photoelectric conversion characteristics, for example, when the organic thin film solar cell is a solar cell, it is desirable that at least one surface of the solar cell is sufficiently transparent in the solar spectrum. The transparent electrode is formed using a known conductive material so as to ensure predetermined translucency by a method such as vapor deposition or sputtering. The light transmittance of the electrode on the light receiving surface is preferably 10% or more. In a preferred configuration of the pair of electrode configurations, one of the electrode portions includes a metal having a high work function, and the other includes a metal having a low work function.

2. Organic thin film layer The organic thin film layer is either a p layer, a mixed layer (i layer) of p material and n material, or an n layer or a buffer layer. When the material of the present invention is used for the organic thin film layer, specifically, the lower electrode / the single layer of the material of the present invention / the upper electrode, the lower electrode / the material of the present invention, and the n layer material or p layer described later. Examples include a mixed layer / material with the material / upper electrode.

3. p layer, n layer, i layer The p layer is a layer that transports holes, the n layer is a layer that transports electrons, and the n layer is particularly limited when the material of the present invention is used for the p layer. However, a compound having a function as an electron acceptor is preferable. For example, in the case of organic compounds, C60 and C70 fullerenes, fullerene derivatives, carbon nanotubes, perylene derivatives, polycyclic quinones, quinacridones, and the like, such as CN-poly (phenylene-vinylene), MEH-CN-PPV, and -CN in polymer systems Groups or CF ₃ group-containing polymers, their -CF ₃ substituted polymers, poly (fluorene) derivatives, and the like. A material having high electron mobility is preferred. Further, a material having a small electron affinity is preferable. Thus, a sufficient open-circuit voltage can be realized by combining materials having a small electron affinity as the n layer.

As materials for the n-layer and i-layer, fullerene and fullerene derivatives are preferable.
The structures of fullerene C60 and fullerene C70 are shown below. Moreover, as a fullerene derivative, the thing of the structure shown below is mentioned, for example.

Moreover, if it is an inorganic compound, the inorganic semiconductor compound of an n-type characteristic can be mentioned. Specifically, doping semiconductors and compound semiconductors such as n-Si, GaAs, CdS, PbS, CdSe, InP, Nb ₂ O ₅ , WO ₃ , Fe ₂ O ₃ , titanium dioxide (TiO ₂ ), monoxide Examples include titanium oxide such as titanium (TiO) and dititanium trioxide (Ti ₂ O ₃ ), and conductive oxides such as zinc oxide (ZnO) and tin oxide (SnO ₂ ). You may use combining more than a seed. Preference is given to using titanium oxide, particularly preferably titanium dioxide.

  When the material of the present invention is used for the n layer, the p layer is not particularly limited, but a compound having a function as a hole acceptor is preferable. For example, in the case of an organic compound, N, N′-bis (3-tolyl) -N, N′-diphenylbenzidine (mTPD), N, N′-dinaphthyl-N, N′-diphenylbenzidine (NPD), 4, Amine compounds represented by 4 ′, 4 ″ -tris (phenyl-3-tolylamino) triphenylamine (MTDATA), etc., phthalocyanine (Pc), copper phthalocyanine (CuPc), zinc phthalocyanine (ZnPc), titanyl phthalocyanine (TiOPc) ), Phthalocyanines such as octaethylporphyrin (OEP), platinum octaethylporphyrin (PtOEP), zinc tetraphenylporphyrin (ZnTPP) and the like, and polymer compounds such as polyhexylthiophene (P3HT), Methoxyethylhexyloxyphe Vinylene (MEHPPV) main chain type conjugated polymers such as side chain type polymers such as represented by polyvinyl carbazole, and the like.

The i layer is a mixed layer of an electron donating material and an electron accepting material. When the material of the present invention is used for the i layer, the i layer may be formed by mixing with the p layer compound or the n layer compound. In this case, any of the above exemplary compounds can be used for the p layer or the n layer.
The i layer can be formed by co-evaporating an electron donating material and an electron accepting material. At this time, the mixing ratio of the electron donating material is 1% by weight to 99% by weight.

（ＰＥＤＯＴ：ＰＳＳについて、ｎ及びｍはそれぞれ繰り返し数である。） 4). Buffer layer In general, organic thin film solar cells often have a thin total film thickness, and therefore, the upper electrode and the lower electrode are short-circuited, and the yield of cell fabrication often decreases. In such a case, it is preferable to prevent this by laminating a buffer layer.
As a preferable compound for the buffer layer, a compound having sufficiently high carrier mobility is preferable so that the short-circuit current does not decrease even when the film thickness is increased. For example, if it is a low molecular compound, the aromatic cyclic acid anhydride represented by NTCDA shown below etc. will be mentioned, and if it is a high molecular compound, poly (3,4-ethylenedioxy) thiophene: polystyrene sulfonate (PEDOT: PSS), polyaniline: camphorsulfonic acid (PANI: CSA), and other known conductive polymers.

(For PEDOT: PSS, n and m are the number of repetitions.)

In addition, the buffer layer may have a role of preventing excitons from diffusing to the electrodes and deactivating. Inserting a buffer layer as an exciton blocking layer in this way is effective for increasing efficiency. The exciton blocking layer can be inserted on either the positive electrode side or the negative electrode side, or both can be inserted simultaneously. In this case, as a preferable material for the exciton blocking layer, for example, a well-known material for a hole barrier layer or a material for an electron barrier layer in organic EL applications can be used. A preferable material for the hole blocking layer is a compound having a sufficiently large ionization potential, and a preferable material for the electron blocking layer is a compound having a sufficiently small electron affinity. Specifically, bathocuproin (BCP), bathophenanthroline (BPhen), and the like, which are well-known materials for organic EL applications, can be used as the cathode-side hole barrier layer material.

Furthermore, you may use the inorganic semiconductor compound illustrated as said n material for a buffer layer. As the p-type inorganic semiconductor compound, CdTe, p-Si, SiC, GaAs, WO ₃ or the like can be used.

5. Substrate The substrate preferably has mechanical and thermal strength and transparency. For example, there are a glass substrate and a transparent resin film. Transparent resin films include polyethylene, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, polypropylene, polystyrene, polymethyl methacrylate, polyvinyl chloride, polyvinyl alcohol, polyvinyl butyral, nylon, polyether ether ketone. , Polysulfone, polyethersulfone, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, polyvinyl fluoride, tetrafluoroethylene-ethylene copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, polychlorotrifluoroethylene, Polyvinylidene fluoride, polyester, polycarbonate, polyurethane, polyimide, polyetherimide, polyimide, polypropylene, etc. It is.

[Method of manufacturing organic thin film solar cell]
The formation of each layer of the organic thin film solar cell of the present invention is performed by a dry film formation method such as vacuum deposition, sputtering, plasma, ion plating, or wet film formation such as spin coating, dip coating, casting, roll coating, flow coating, and ink jet. The law can be applied.
The thickness of each layer is not particularly limited, but is set to an appropriate thickness. Since it is generally known that the exciton diffusion length of an organic thin film is short, if the film thickness is too thick, the exciton is deactivated before reaching the heterointerface, resulting in low photoelectric conversion efficiency. If the film thickness is too thin, pinholes and the like are generated, so that sufficient diode characteristics cannot be obtained, resulting in a decrease in conversion efficiency. The normal film thickness is suitably in the range of 1 nm to 10 μm, but more preferably in the range of 5 nm to 0.2 μm.

In the case of the dry film forming method, a known resistance heating method is preferable, and for forming the mixed layer, for example, a film forming method by simultaneous vapor deposition from a plurality of evaporation sources is preferable. More preferably, the substrate temperature is controlled during film formation.
In the case of a wet film forming method, a material for forming each layer is dissolved or dispersed in an appropriate solvent to prepare a light-emitting organic solution to form a thin film, and any solvent can be used. For example, halogenated hydrocarbon solvents such as dichloromethane, dichloroethane, chloroform, carbon tetrachloride, tetrachloroethane, trichloroethane, chlorobenzene, dichlorobenzene, chlorotoluene, ether solvents such as dibutyl ether, tetrahydrofuran, dioxane, anisole, methanol, Alcohol solvents such as ethanol, propanol, butanol, pentanol, hexanol, cyclohexanol, methyl cellosolve, ethyl cellosolve, ethylene glycol, hydrocarbon solvents such as benzene, toluene, xylene, ethylbenzene, hexane, octane, decane, tetralin, Examples include ester solvents such as ethyl acetate, butyl acetate, and amyl acetate. Of these, hydrocarbon solvents or ether solvents are preferable. These solvents may be used alone or in combination. In addition, the solvent which can be used is not limited to these.

In the present invention, in any organic thin film layer of the organic thin film solar cell, an appropriate resin or additive may be used for improving the film formability and preventing pinholes in the film. Usable resins include polystyrene, polycarbonate, polyarylate, polyester, polyamide, polyurethane, polysulfone, polymethyl methacrylate, polymethyl acrylate, cellulose and other insulating resins and copolymers thereof, poly-N-vinyl. Examples thereof include photoconductive resins such as carbazole and polysilane, and conductive resins such as polythiophene and polypyrrole.
Examples of the additive include an antioxidant, an ultraviolet absorber, and a plasticizer.

  The organic thin film solar cell of the present invention can be used as a power source or an auxiliary power source for various devices such as watches, mobile phones and mobile personal computers, and electrical appliances. Combined with a rechargeable battery with a charging function, it can be used in the dark, and the application can be expanded.

[Synthesis of compounds for organic thin film solar cell elements]
Example 1
Compound 2 was prepared according to the following synthetic scheme.

(1) Synthesis of Intermediate 2-A Pyrrol (250 ml) and benzaldehyde (88.6 mmol, 9.4 g) were placed in a 500 ml flask, and trifluoroacetic acid (1.2 ml) was added while stirring at room temperature. . The reaction was allowed to proceed at room temperature for 25 minutes, and the reaction was stopped by adding an aqueous sodium hydroxide solution (250 ml).
The reaction mixture was extracted with 300 ml of methylene chloride, and the organic layer was further washed with 200 ml of an aqueous sodium hydroxide solution. After drying the organic layer with sodium sulfate, the solvent and excess pyrrole were removed using an evaporator. The resulting black oil was purified twice by silica gel column chromatography (hexane / ethyl acetate = 80/20) to obtain pale brown crystals (12.7 g, yield 65%).

It was confirmed by ¹ H-NMR that the obtained compound was Intermediate 2-A. The measurement result of ¹ H-NMR is shown below.
¹ H-NMR (400 MHz, CDCl ₃ , TMS) δ 7.92 (2H, br), 7.16-7.33 (5H, m), 6.68 (2H, d), 6.14 (2H, d ), 5.91 (2H, s), 5.46 (1H, s)

(2) Synthesis of Compound 1 Intermediate 2000-A (36.9 mmol, 8.2 g) and 850 ml of methylene chloride were placed in a 2000 ml flask and stirred at room temperature. To this solution, 120 ml of 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) (36.9 mmol, 8.4 g) in methylene chloride was added and stirred at room temperature for 7 hours. The solvent was completely removed from the reaction mixture using an evaporator. The obtained reaction product was put into a 1000 ml flask, and the inside of the system was decompressed with a vacuum pump to perform nitrogen substitution. After performing this operation three times, 500 ml of toluene and N, N-diisopropylethylamine (369 mmol, 45.5 ml) were added and stirred at room temperature for 10 minutes. Next, boron trifluoride diethyl ether complex (369 mmol, 64.2 ml) was added, and the mixture was heated and stirred at room temperature for 1 hour and at 80 ° C. for 6 hours.
The reaction solution was filtered through celite, the solvent was removed using an evaporator, and the green light emitting fraction was fractionated by silica column chromatography (methylene chloride only). The obtained fraction was further purified by silica column chromatography (hexane / methylene chloride = 70 / 30-60 / 40) to obtain reddish brown crystals (2.0 g, yield 20%).

It was confirmed by ¹ H-NMR that the obtained compound was Compound 1. The measurement result of ¹ H-NMR is shown below.
¹ H-NMR (400 MHz, CDCl ₃ , TMS) δ 7.94 (2H, s), 7.50-7.60 (5H, m), 6.93 (2H, d), 6.54 (2H, d )

(3) Synthesis of Intermediate 2-B Compound 1 (4.0 mmol, 1.1 g) was placed in a 300 ml flask, and the inside of the system was decompressed with a vacuum pump to perform nitrogen substitution. After performing this operation three times, N, N-dimethylformamide (100 ml) and methylene chloride (100 ml) were added and stirred at room temperature. From the dropping funnel, N-bromosuccinimide (9.6 mmol, 1.7 g) dissolved in 60 ml of methylene chloride was added dropwise over 30 minutes. The reaction was further continued at room temperature for 16 hours.
The reaction solution was washed 3 times with 200 ml of water, the organic layer was dried over sodium sulfate, and then the solvent was removed using an evaporator. The obtained oil was purified by silica gel column chromatography (hexane / ethyl acetate = 90 / 10-85 / 15) to obtain brown crystals (1.6 g, yield 93%).

It was confirmed by ¹ H-NMR that the obtained compound was intermediate 2-B. The measurement result of ¹ H-NMR is shown below.
¹ H-NMR (400 MHz, CDCl ₃ , TMS) δ 7.85 (2H, s), 7.50-7.65 (5H, m), 6.95 (2H, s)

(4) Synthesis of Compound 2 Intermediate 1 (2.8 mmol, 1.2 g), phenylboronic acid (6.7 mmol, 0.82 g), trisdibenzylideneacetone dipalladium (0.28 mmol, 0.25 g) in a 1000 ml flask. ), Tritert-butylphosphine tetrafluoroborate (1.12 mmol, 0.32 g) and cesium carbonate (11.2 mmol, 3.6 g), and the inside of the system was depressurized with a vacuum pump to perform nitrogen substitution. It was. After performing this operation three times, tetrahydrofuran (600 ml) and 4 ml of water were added, and the mixture was stirred at room temperature for 16 hours.
The solvent was removed from the reaction solution using an evaporator, extracted with 300 ml of methylene chloride and 200 ml of water, and the organic layer was dried over sodium sulfate. The oil obtained after removing the solvent was purified by silica gel column chromatography (hexane / methylene chloride = 85/15 to 65/35) to obtain brown crystals (0.6 g, yield 54%).

It was confirmed by ¹ H-NMR and FD-MS (Field Desorption Mass Spectrometry) that the obtained compound was Compound 2. The measurement results of ¹ H-NMR and FD-MS are shown below.
[ ¹ H-NMR]
¹ H-NMR (500 MHz, CD ₂ Cl ₂ , TMS) δ 8.30 (2H, s), 7.66-7.71 (3H, m), 7.62 (2H, t), 7.58 (4H D), 7.39 (4H, t), 7.29 (2H, t), 7.18 (2H, t)
[FD-MS]
m / z 420 (420.16 for C ₂₇ H ₁₉ BF ₂ N ₂ )

Example 2
Compound 3 was prepared according to the following synthetic scheme.

Intermediate 2-B was synthesized in the same manner as Example 1.
In a 1000 ml flask, intermediate 2-B (3.7 mmol, 1.6 g), o-methoxyphenylboronic acid (9.3 mmol, 1.5 g), trisdibenzylideneacetone dipalladium (0.37 mmol, 0.34 g), Tritert-butylphosphine tetrafluoroborate (1.49 mmol, 0.43 g) and cesium carbonate (14.9 mmol, 4.8 g) were added, and the inside of the system was decompressed with a vacuum pump to perform nitrogen substitution. After performing this operation three times, tetrahydrofuran (650 ml) and 5 ml of water were added, and the mixture was stirred at room temperature for 15 hours.
The solvent was removed from the reaction solution using an evaporator, extracted with 300 ml of methylene chloride and 200 ml of water, and the organic layer was dried over sodium sulfate. The oil obtained after removing the solvent was purified by silica gel column chromatography (hexane / ethyl acetate = 80/20) to obtain brown crystals (0.53 g, yield 30%).

It was confirmed by ¹ H-NMR and FD-MS (Field Desorption Mass Spectrometry) that the obtained compound was Compound 3. The measurement results of ¹ H-NMR and FD-MS are shown below.
[ ¹ H-NMR]
¹ H-NMR (500 MHz, CD ₂ Cl ₂ , TMS) δ 8.48 (2H, s), 7.68 (2H, d), 7.62 (1H, t), 7.60 (2H, t), 7.48 (2H, d), 7.23-7.28 (4H, m), 6.88-7.00 (4H, m), 3.90 (6H, s)
[FD-MS]
m / z 480 (480.3 for C ₂₉ H ₂₃ BF ₂ N ₂ O ₂ )

Example 3
Compound 10 was prepared according to the following synthetic scheme.

(1) Synthesis of Intermediate 10-A Compound 1 was synthesized in the same manner as Example 1.
Compound 1 (4.1 mmol, 1.1 g) was placed in a 300 ml flask, and the inside of the system was decompressed with a vacuum pump to perform nitrogen substitution. After performing this operation three times, N, N-dimethylformamide (100 ml) and methylene chloride (100 ml) were added and stirred at room temperature. From the dropping funnel, N-bromosuccinimide (4.9 mmol, 0.87 g) dissolved in 40 ml of methylene chloride was added dropwise over 40 minutes. Furthermore, it was made to react at room temperature for 20 hours.
The reaction solution was washed 3 times with 200 ml of water, the organic layer was dried over sodium sulfate, and then the solvent was removed using an evaporator. The obtained oil was purified by silica gel column chromatography (hexane / ethyl acetate = 80/20) to obtain brown crystals (1.28 g, yield 90%).

(2) Synthesis of Compound 10 Intermediate 10-A (3.6 mmol, 1.3 g), 5- (4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl in a 1000 ml flask ) -2,2′-bithiophene) (4.3 mmol, 1.3 g), trisdibenzylideneacetone dipalladium (0.36 mmol, 0.33 g), tritert-butylphosphine tetrafluoroborate (1.44 mmol, 0 .42 g) and cesium carbonate (14.4 mmol, 4.7 g) were added, and the inside of the system was depressurized with a vacuum pump to perform nitrogen substitution. After performing this operation 3 times, tetrahydrofuran (500 ml) and 5 ml of water were added and stirred at room temperature for 18 hours.
The solvent was removed from the reaction solution using an evaporator, extracted with 300 ml of methylene chloride and 200 ml of water, and the organic layer was dried over sodium sulfate. The oil obtained after removing the solvent was purified by silica gel column chromatography (toluene only) to obtain dark brown crystals (0.90 g, yield 57%).

It was confirmed by ¹ H-NMR and FD-MS (Field Desorption Mass Spectrometry) that the obtained compound was compound 10. The measurement results of ¹ H-NMR and FD-MS are shown below.
[ ¹ H-NMR]
¹ H-NMR (400 MHz, CDCl ₃ , TMS) δ 8.18 (1H, s), 7.96 (1H, s), 7.57-7.65 (5H, m), 7.21 (1H, d ), 7.15 (1H, d), 7.10 (1H, d), 7.07 (1H, d), 7.01 (1H, dd), 6.95 (1H, d), 6.92 (1H, s), 6.57 (1H, s)
[FD-MS]
m / z 432 (432.3 for C ₂₃ H ₁₅ BF ₂ N ₂ S ₂ )

Reference Example Compound 15 was produced according to the following synthesis scheme.

(1) Synthesis of Intermediate 15-A Pyrrol (70 ml) and 5-formyl-2,2′-bithiophene (50 mmol, 9.7 g) were placed in a 200 ml flask and stirred at room temperature while trifluoroacetic acid ( 1.0 ml) was added. The reaction was allowed to proceed at room temperature for 20 minutes, and the reaction was stopped by adding an aqueous sodium hydroxide solution (200 ml).
The reaction mixture was extracted with 200 ml of methylene chloride, and the organic layer was further washed with 200 ml of an aqueous sodium hydroxide solution. After drying the organic layer with sodium sulfate, the solvent and excess pyrrole were removed using an evaporator. The obtained residue was passed through silica gel column chromatography (methylene chloride only), and further purified by silica gel column chromatography (hexane / ethyl acetate = 85/25). The obtained crystals were recrystallized from hexane-ethyl acetate to obtain white crystals (7.5 g, yield 48%).

It was confirmed by ¹ H-NMR that the obtained compound was Intermediate 15-A. The measurement result of ¹ H-NMR is shown below.
¹ H-NMR (400 MHz, CDCl ₃ , TMS) δ 8.01 (2H, br), 7.17 (1H, d), 7.08 (1H, d, J = 7 Hz), 6.96-7.01 (2H, m), 6.79 (1H, s), 6.71 (2H, s), 6.18 (2H, d), 6.09 (2H, s), 5.70 (1H, s)

(2) Synthesis of Compound 15 Intermediate 15-A (24.1 mmol, 7.5 g) and 500 ml of methylene chloride were placed in a 1000 ml flask and stirred at room temperature. To this solution, 150 ml of 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) (24.1 mmol, 5.5 g) in methylene chloride was added and stirred at room temperature for 5 hours. The solvent was completely removed from the reaction mixture using an evaporator. The obtained reaction product was put into a 500 ml flask, and the inside of the system was decompressed with a vacuum pump to perform nitrogen substitution. After performing this operation three times, 350 ml of toluene and N, N-diisopropylethylamine (240 mmol, 41.8 ml) were added and stirred at room temperature for 15 minutes. Next, boron trifluoride diethyl ether complex (240 mmol, 29.6 ml) was added, and the mixture was stirred with heating at room temperature for 1 hour and at 80 ° C. for 6 hours.
The reaction solution was filtered through celite, the solvent was removed using an evaporator, and then passed through a silica column (methylene chloride only). The obtained fraction was further purified by silica column chromatography (hexane / methylene chloride = 70/30) to obtain black-brown crystals (2.0 g, yield 23%).

It was confirmed by ¹ H-NMR and FD-MS (Field Desorption Mass Spectrometry) that the obtained compound was Compound 15. The measurement results of ¹ H-NMR and FD-MS are shown below.
[ ¹ H-NMR]
¹ H-NMR (500 MHz, CD ₂ Cl ₂ , TMS) δ 7.90 (2H, s), 7.57 (1H, d), 7.38-7.41 (5H, m), 7.12 (1H , Dd), 6.63 (2H, br)
[FD-MS]
m / z 356 (356.2 for C ₁₇ H ₁₁ BF ₂ N ₂ S ₂ )

Example 5
Compound 18 was prepared according to the following synthetic scheme.

(1) Synthesis of Intermediate 18-A Into a 200 ml flask was added pyrrole (60 ml) and 4- (N, N-diphenylamino) benzaldehyde (39 mmol, 10.6 g), and while stirring at room temperature, trifluoroacetic acid (1.0 ml) was added. The reaction was allowed to proceed at room temperature for 20 minutes, and the reaction was stopped by adding an aqueous sodium hydroxide solution (200 ml).
The reaction mixture was extracted with 200 ml of methylene chloride, and the organic layer was further washed with 200 ml of an aqueous sodium hydroxide solution. After drying the organic layer with sodium sulfate, the solvent and excess pyrrole were removed using an evaporator. The obtained residue was purified by silica gel column chromatography (hexane / ethyl acetate = 80/20) to obtain pale brown crystals (10.5 g, yield 70%).

(2) Synthesis of Compound 18 Intermediate 18-A (27 mmol, 10.5 g) and 500 ml of tetrahydrofuran were placed in a 1000 ml flask and stirred at room temperature. To this solution was added 50 ml of 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) (27 mmol, 6.1 g) in tetrahydrofuran, and the mixture was stirred at room temperature for 2 hours. The solvent was completely removed from the reaction mixture using an evaporator. The obtained reaction product was put into a 1000 ml flask, and the inside of the system was decompressed with a vacuum pump to perform nitrogen substitution. After performing this operation three times, 400 ml of toluene and N, N-diisopropylethylamine (270 mmol, 47.0 ml) were added and stirred at room temperature for 15 minutes. Subsequently, boron trifluoride diethyl ether complex (270 mmol, 33.3 ml) was added, and the mixture was heated and stirred at room temperature for 1 hour and at 80 ° C. for 2 hours.
The reaction solution was filtered through celite, the solvent was removed using an evaporator, and then passed through a silica column (methylene chloride only). The obtained fraction was further purified by silica column chromatography (hexane / methylene chloride = 75/25) to obtain black-brown crystals (5.2 g, yield 44%).

It was confirmed by ¹ H-NMR and FD-MS (Field Desorption Mass Spectrometry) that the obtained compound was compound 18. The measurement results of ¹ H-NMR and FD-MS are shown below.
[ ¹ H-NMR]
¹ H-NMR (500 MHz, CD ₂ Cl ₂ , TMS) δ 7.89 (2H, s), δ 7.49 (2H, dt) 7.37 (4H, td), 7.23 (4H, dd), 7 .18 (2H, td), 6.95-7.15 (4H, m), 6.54 (2H, dd)
[FD-MS]
_{m / z 435 (435.2 for C} 27 H 20 BF 2 N 3)

[Production of organic solar cells]
Example 6
A glass substrate with an ITO transparent electrode having a thickness of 25 mm × 75 mm × 0.7 mm was subjected to ultrasonic cleaning in isopropyl alcohol for 5 minutes, and then UV ozone cleaning was performed for 30 minutes. The glass substrate with a transparent electrode line after washing was mounted on a substrate holder of a vacuum deposition apparatus.
On the surface on the side where the transparent electrode line, which is the lower electrode, is formed, the compound 3 prepared in Example 2 so as to cover the transparent electrode is formed at 1 Å / s by resistance heating vapor deposition, and the film thickness is 30 nm. Compound A film (p layer) was formed. A C60 film (n layer) having a thickness of 60 nm was formed on the compound A film at 1 Å / s by thermal evaporation, and subsequently, a BCP film (buffer layer) having a thickness of 10 nm was formed at 1 Å / s. Finally, a metal Al film having a thickness of 100 nm was deposited as a counter electrode to produce an organic solar cell (element area: 0.25 cm ² ).

The material used for manufacture of the said organic solar cell is shown below.

The obtained organic thin film solar cell, the following method, the measurement of the current-voltage characteristic (I-V characteristic) in air mass AM1.5 conditions (light intensity ^{_{(P in) 100mW / cm 2}} ). Table 1 shows the results of open circuit voltage (Voc), short circuit current density (Jsc), fill factor (FF), and conversion efficiency (η).
At the time of evaluating the solar cell characteristics, the manufactured element was covered with an optical mask, and the solar cell characteristics in an area of 0.00225 cm ² were measured. Further, the conversion efficiency η [%] was calculated from Voc × Jsc × FF / P _in × 100.
The conversion efficiency eta, the incident light energy P _in is constant, thus showing the transformation efficiency Voc, either Jsc and FF of 1 or more is good as a large compound.

Example 7
An organic thin film solar cell was produced and evaluated in the same manner as in Example 6 except that the p layer was laminated using the compound 10 instead of the compound 3. The results are shown in Table 1.

Example 8
A glass substrate with an ITO transparent electrode having a thickness of 25 mm × 75 mm × 0.7 mm was subjected to ultrasonic cleaning in isopropyl alcohol for 5 minutes, and then UV ozone cleaning was performed for 30 minutes. The glass substrate with a transparent electrode line after washing was mounted on a substrate holder of a vacuum deposition apparatus.
A compound 10 film (p layer) having a thickness of 10 nm was formed at 1 Å / s by resistance heating vapor deposition on the surface on the side where the transparent electrode line as the lower electrode was formed, so as to cover the transparent electrode. Subsequently, the compound 10 was co-evaporated at 0.5 Å / s to a film thickness of 5 nm and C60 at 1 Å / s to a film thickness of 20 nm to form an i layer (mixed layer). A C60 film (n layer) having a thickness of 40 nm was formed on the i layer by heating evaporation at 1 Å / s. Further, a BCP film having a thickness of 10 nm was formed as a buffer layer at 1 Å / s. Finally, metal Al was deposited to a thickness of 100 nm as a counter electrode to produce an organic thin film solar cell.
The obtained organic thin film solar cell was evaluated in the same manner as in Example 6. The results are shown in Table 1.

Comparative Example 1
An organic thin film solar cell was manufactured and evaluated in the same manner as in Example 6 except that the p-layer was laminated using the following compound A instead of the compound 3. The results are shown in Table 1.

Comparative Example 2
An organic thin film solar cell was produced and evaluated in the same manner as in Example 6 except that the p-layer was laminated using the following compound B instead of the compound 3. The results are shown in Table 1.

  As can be seen from Table 1, the organic thin film solar cell material of the present invention has high Jsc and good conversion efficiency as compared with conventional pyromethene derivatives (Compound A in Comparative Examples 1 and 2 and Compound B in Comparative Example 2), and an excellent solar cell. It turns out that the characteristic is shown.

  The organic thin film solar cell material of the present invention can be used for an organic thin film solar cell, and this organic thin film solar cell can be used as a power source for various devices such as watches, mobile phones and mobile personal computers, and electrical appliances.

Claims (10)

The material for organic thin-film solar cell elements containing the compound represented by following formula (1).

( Wherein R ⁰ is a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 20 ring carbon atoms, and R ^{1 to} R ⁴ are Each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 20 ring carbon atoms, or a substituted or unsubstituted ring atom having 5 to 5 ring atoms. 20 heterocyclic groups, and adjacent ones of R ^{0 to} R ⁴ may be bonded to each other to form a ring.
X is each independently a halogen atom or an alkoxy group. )   The organic thin film solar cell element material according to claim 1, wherein two Xs in the formula (1) are fluorine atoms. The organic thin-film solar cell element material according to claim 1 or 2, wherein the compound represented by the formula (1) is a compound represented by the following formula (2) or a compound represented by the following formula (3).

  The organic thin-film solar cell element material according to any one of claims 1 to 3, wherein the compound represented by any one of the formulas (1) to (3) is used for the p layer or the i layer. An organic thin-film solar battery comprising one or more organic thin-film layers between a pair of electrodes, wherein at least one of the organic thin-film layers contains a compound represented by the following formula (1).

( Wherein R ⁰ is a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 20 ring carbon atoms, and R ^{1 to} R ⁴ are Each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 20 ring carbon atoms, or a substituted or unsubstituted ring atom having 5 to 5 ring atoms. 20 heterocyclic groups, and adjacent ones of R ^{0 to} R ⁴ may be bonded to each other to form a ring.
X is each independently a halogen atom or an alkoxy group. )   The organic thin-film solar cell according to claim 5, wherein two Xs in the formula (1) are fluorine atoms. The organic thin film solar cell according to claim 5 or 6, wherein the compound represented by the formula (1) is a compound represented by the following formula (2) or a compound represented by the following formula (3).

  The one or more organic thin film layers are any one of a p layer, an i layer, and an n layer, and the p layer and / or the i layer are represented by any one of the formulas (1) to (3). The organic thin-film solar cell in any one of Claims 5-7 containing a compound.   The organic thin film solar cell according to claim 8, wherein the n layer and / or the i layer further contains fullerene or a fullerene derivative.   The apparatus which comprises the organic thin-film solar cell in any one of Claims 5-9.