JP2014114265A - DITHIOPHENE COMPOUND, π-ELECTRON CONJUGATED POLYMER HAVING DITHIOPHENE GROUP AND ORGANIC SEMICONDUCTOR DEVICE USING POLYMER - Google Patents

Abstract

（式中、Ｒ^１、Ｒ^２、Ｒ^３及びＲ^４は同一又は異なる水素原子、フッ素原子、置換基を有してもよい炭素数１〜２０のアルキル基、置換基を有してもよい炭素数６〜２０のアリール基又は置換基を有してもよい炭素数４〜２０のヘテロアリール基である。Ｘは炭素、ケイ素及びゲルマニウムから選ばれる元素で同一または異なる。Ａｒは置換基を有してもよい（複素）芳香環を含む２価の基である。）
【選択図】なしAn organic semiconductor device including a narrow band gap polymer capable of photoelectric conversion in the visible to near-infrared region and capable of expressing a high voltage (V _oc ), a photoelectric conversion element, and optimal for such an organic semiconductor device A π-electron conjugated polymer is provided.
A π-electron conjugated polymer having a repeating unit represented by chemical formula (2), an organic semiconductor device and a photoelectric conversion element having the π-electron conjugated polymer.

(In formula, R < ¹ >, R < ² >, R < ³ > and R < ⁴ > may have the same or different hydrogen atom, fluorine atom, C1-C20 alkyl group which may have a substituent, and a substituent. An aryl group having 6 to 20 carbon atoms or an optionally substituted heteroaryl group having 4 to 20 carbon atoms, X is an element selected from carbon, silicon and germanium, and Ar is a substituent. (It is a divalent group containing a (hetero) aromatic ring which may be present.)
[Selection figure] None

Description

  The present invention relates to a novel dithiophene compound, a π-electron conjugated polymer of a (hetero) aromatic ring compound having the dithiophene group as a part of a polymer chain, a composition using the π-electron conjugated polymer, and an organic semiconductor device .

  Solar cells are currently attracting attention as an effective energy source for increasing energy problems. As semiconductor materials for photovoltaic elements in solar cells, inorganic semiconductors such as compound semiconductors, amorphous silicon, polycrystalline silicon, and single crystal silicon are used. However, solar cell power generation is expensive compared to thermal power generation and nuclear power generation, which are currently mainstream, due to the high manufacturing cost of the inorganic semiconductor. A main factor that increases the manufacturing cost is that a thin film is formed by a vapor deposition process under high temperature and vacuum conditions. On the other hand, when an organic material such as a conjugated polymer is used as a semiconductor material, there is an advantage that a vapor deposition process is unnecessary and the manufacturing process can be simplified. For this reason, studies on solar cells (photoelectric conversion elements) using organic semiconductors and organic dyes are underway.

Factors that determine the performance of the organic photoelectric conversion element mainly include a short circuit current density (J _SC ), an open circuit voltage (V _OC ), and a fill factor (FF). Among them, J _SC is because it is highly dependent on the optical absorption properties of the semiconductor material, it is possible to better light absorbing region is wide material of the material converts to a current more light. In an organic material, a compound having a wide light absorption region needs to have a small energy difference (band gap) between the highest occupied orbital (HOMO) level and the lowest unoccupied orbital (LUMO) level. In addition, from the viewpoint of the coatability of a compound at the time of device fabrication, research on polymers rather than small molecules has been actively promoted.

  Examples of compounds having these characteristics include narrow band gap polymers. For example, Non-Patent Document 1 discloses an example of an alternating copolymer of cyclopentadithiophene as a donor molecule and benzothiadiazole as an acceptor molecule as an example of a narrow band gap polymer. Examples of alternating copolymers with benzothiadiazole using dithienosilol as a donor molecule so as to have a wider light absorption region are disclosed in Patent Document 1 and Non-Patent Document 2.

Narrow bandgap polymers disclosed in Patent Document 1, Non-Patent Document 1 and Non-Patent Document 2 have a wide absorption wavelength band, and organic solar cells produced using these have promising high _JSC and photoelectric conversion efficiency. Material. However, organic photoelectric conversion elements using these narrow band gap polymers have a problem of low _VOC , and improvement is desired.

Special table 2010-507233 gazette

Journal of the American Chemical Society, 2008, 130, pp 3619-3623 Journal of the American Chemical Society, 2008, 130, pp 16144-16145

The present invention has been made to solve the above-mentioned problems, and provides a novel dithiophene compound for polymerizing a π-electron conjugated polymer having a low HOMO level while being a narrow band gap polymer. An object is to provide a π-electron conjugated polymer to be polymerized. It is another object of the present invention to provide an organic semiconductor device and a photoelectric conversion element that contain such a π-electron conjugated polymer and express a high voltage (V _OC ).

The invention according to claim 1 of the present invention made to achieve the above object is a dithiophene compound represented by the following chemical formula (1).

In chemical formula (1), R ¹ , R ² , R ³ and R ⁴ each independently have a hydrogen atom, a fluorine atom, a C 1-20 alkyl group which may have a substituent, or a substituent. The aryl group having 6 to 20 carbon atoms or the heteroaryl group having 4 to 20 carbon atoms which may have a substituent may be the same or different. X is selected from carbon, silicon and germanium, and may be the same or different. M ^p1 is independently a halogen atom, boronic acid, boronic acid ester, —MgY, —ZnY, —SiY ₃ and —SnR ^a ₃ (wherein R ^a is a linear alkyl group having 1 to 4 carbon atoms, Y is Halogen atom).

Similarly, the invention according to claim 2 of the present invention is characterized by having a repeating unit represented by the following chemical formula (2) and having a number average molecular weight of 1,000 to 1,000,000 g / mol. It is a conjugated polymer.

In chemical formula (2), R ¹ , R ² , R ³ and R ⁴ have the same or different hydrogen atom, fluorine atom, optionally substituted alkyl group having 1 to 20 carbon atoms and substituent. Or an aryl group having 6 to 20 carbon atoms or a heteroaryl group having 4 to 20 carbon atoms which may have a substituent. X is an element selected from carbon, silicon and germanium and is the same or different. Ar is a divalent group containing a (hetero) aromatic ring which may have a substituent.

The invention according to claim 3 of the present invention is the π-electron conjugated polymer of the invention according to claim 2, wherein each of R ¹ , R ² , R ³ and R ⁴ independently has a substituent. It may be an alkyl group having 1 to 20 carbon atoms.

  Similarly, the invention according to claim 4 is the π-electron conjugated polymer of the invention according to claim 2 or 3, wherein each X is independently silicon or germanium.

  The invention according to claim 5 is the π-electron conjugated polymer of the invention according to any one of claims 2 to 4, wherein Ar is a monocyclic (hetero) aromatic ring which may have a substituent and / or Or it is a bivalent group containing the condensed (hetero) aromatic ring which may have a substituent.

The invention according to claim 6 is the π-electron conjugated polymer of the invention according to claim 5, wherein Ar includes at least one (hetero) aromatic ring selected from the following chemical formulas (a) to (u): It is a divalent group.

In the chemical formulas (a) to (u),
R ⁵ and R ^{5 ′} are each independently a hydrogen atom, a fluorine atom, or a linear, branched or cyclic hydrocarbon group having 1 to 20 carbon atoms which may have a substituent. The hydrogen group may be interrupted by an oxygen atom or a sulfur atom. R ⁵ and R ^{5 ′} may form a ring. R ⁶ and R ^{6 ′} are each independently a hydrogen atom or a linear, branched or cyclic hydrocarbon group having 1 to 20 carbon atoms which may have a substituent, and the hydrocarbon group is oxygen It may be interrupted by atoms or sulfur atoms. R ⁶ and R ^{6 ′} may form a ring. R ⁷ and R ^{7 ′} are each independently a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent, and this hydrocarbon group may be interrupted by an oxygen atom or a sulfur atom. R ⁸ and R ^{8 ′} are each independently a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent, and this hydrocarbon group may be interrupted by an oxygen atom or a sulfur atom. R ⁸ and R ^{8 ′} may form a ring. R ⁹ and R ^{9 ′} are each independently a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent. R ¹⁰ and R ^{10 ′} are each independently a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent. R ¹¹ is a hydrogen atom or a halogen atom. )

  The invention according to claim 7 is an organic semiconductor composition comprising the π-electron conjugated polymer according to any one of claims 2 to 6.

  The invention according to claim 8 is an organic semiconductor device comprising the π-electron conjugated polymer according to any one of claims 2 to 6.

  In the invention according to claim 9, the organic semiconductor device according to claim 8 is a photoelectric conversion element.

  An invention according to claim 10 is an electric conversion element having a layer containing the π-electron conjugated polymer according to any one of claims 2 to 6 and an electron-accepting material.

  The invention according to claim 11 is a tandem photoelectric conversion element comprising the photoelectric conversion element according to claim 9 or 10.

According to the present invention, a π-electron conjugated polymer having a low HOMO level while being a narrow band gap polymer can be provided. Moreover, it becomes possible to express high _VOC by the organic photoelectric conversion element using the π-electron conjugated polymer of the present invention.

It is a schematic cross section of the photoelectric conversion element by which the (pi) electron conjugated polymer to which this invention is applied contained in the photoactive layer.

  Hereinafter, although the preferable form for implementing this invention is demonstrated in detail, the scope of the present invention is not limited to these forms.

化学反応式（I）において、Ｘ及びＲ^１〜Ｒ^４は前述の化学式（１）と同義である The dithiophene compound represented by the chemical formula (1) of the present invention is an electron donating molecule having a low HOMO level. It is synthesized according to the following chemical reaction formula.

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

  In the chemical reaction formula (I), the compound represented by the chemical formula (6) is described in the literature (Organometallics 1999, Vol. 18, pp. 1453-1459 and Organometallics, 1993, Vol. 12). , 2078-2084).

For example, when M ^p1 is a halogen atom, the dithiophene compound represented by the chemical formula (1) is represented by the chemical formula (6) in an inert gas atmosphere such as nitrogen or argon according to the chemical reaction formula (I). It can be obtained by reacting a compound with a halogenating agent.

  Examples of the halogenating agent include chlorinating agents such as N-chlorosuccinimide, N-chlorophthalimide, chlorine, phosphorus pentachloride, thionyl chloride, and 1,2-dichloro-1,1,2,2-tetrafluoroethane. N-bromosuccinimide, N-bromophthalimide, N-bromoditrifluoromethylamine, bromine, boron tribromide, copper bromide, silver bromide, t-butyl bromide, bromine oxide, 1,2-dibromo Brominating agents such as -1,1,2,2-tetrafluoroethane; iodizing agents such as iodine, iodotrichloride, N-iodophthalimide, and N-iodosuccinimide. Among these, it is preferable to use a brominating agent or an iodinating agent, and it is more preferable to use a brominating agent.

  About the usage-amount of a halogenating agent, it is preferable that it is 2-8 mol with respect to 1 mol of compounds shown by Chemical formula (6). When the amount used is less than 2 mol, there is a possibility that the substitution reaction of bromine becomes insufficient, or the separation and purification work with the compound represented by (1-1) in the chemical formula as the raw material becomes complicated. . On the other hand, when the amount of the halogenating agent used exceeds 8 mol, there is a risk that a substitution reaction other than the intended position may occur or the removal of the unreacted halogenating agent becomes complicated.

  The halogenation reaction is preferably performed in the presence of a solvent. Examples of such solvents include saturated aliphatic hydrocarbons such as pentane, hexane, heptane, octane, nonane, decane, and cyclohexane; aromatic hydrocarbons such as benzene, toluene, ethylbenzene, propylbenzene, xylene, and ethyltoluene; dimethyl ether, Examples thereof include ethers such as ethyl methyl ether, diethyl ether, dipropyl ether, butyl methyl ether, t-butyl methyl ether, dibutyl ether, tetrahydrofuran and 1,4-dioxane. Of these, two or more may be used in combination. The amount of the solvent used is preferably in the range of 1 to 100 parts by weight with respect to 1 part by weight of the compound represented by the chemical formula (6). Moreover, it does not specifically limit about the reaction temperature at the time of making a halogenating agent react, It is preferable that it is the range of -100-100 degreeC. When reaction temperature is less than -100 degreeC, there exists a possibility that reaction rate may become very slow, and it is more preferable that it is -20 degreeC or more. On the other hand, when reaction temperature exceeds 100 degreeC, there exists a possibility of accelerating | stimulating decomposition | disassembly of a product, It is more preferable that it is 50 degrees C or less, and it is still more preferable that it is 10 degrees C or less. The reaction time is preferably 1 minute to 20 hours, and more preferably 0.5 to 10 hours. The reaction pressure is preferably 0 to 3 MPa (gauge pressure).

In the dithiophene compound represented by the chemical formula (1) of the present invention, for example, M ^p1 is other than a halogen atom, that is, boronic acid, boronic acid ester, —MgY, —ZnY, and —SnR ^a ₃ (where R ^a is the number of carbon atoms) 1 to 4 linear alkyl groups, Y is a halogen atom), an intermediate in which both ends are halogenated by first reacting a compound represented by chemical formula (6) with a halogenating agent And then reacting the intermediate with a terminal functionalizing agent. As the halogenating agent used at this time, the halogenating agents exemplified above can be preferably used.

Examples of the terminal functionalizing agent include halogenated trialkyltin, and in this case, M ^p1 of the obtained dithiophene compound (1) is —SnR ^a ₃ . For example, when a boronating agent or a boronic acid esterifying agent is used, M ^p1 becomes boronic acid or a boronic acid ester. The terminal functionalizing agent is not particularly limited, and a terminal functionalizing agent that can obtain a dithiophene compound having a desired M ^p1 may be used as appropriate.

  Specific examples of the trialkyltin halide used as the terminal functionalizing agent include trimethyltin chloride, triethyltin chloride, tri-n-propyltin chloride, and tri-n-butyltin chloride. Among them, it is desirable to use trimethyltin chloride. Specific examples of the boronating agent include trimethyl borate, triethyl borate, tri-n-propyl borate, tri-n-butyl borate, triisopropyl borate and the like. Among them, it is desirable to use trimethyl borate from the viewpoint of reaction efficiency. Specific examples of the boronic acid esterifying agent include, for example, 4, 4, 5, 5-tetramethyl-1, 3, 2-dioxaborolane, 2-methoxy-4, 4, 5, 5-tetramethyl-1, 3, Examples include 2-dioxaborolane, 2-isopropoxy-4, 4,5,5-tetramethyl-1,3,2-dioxaborolane. Among these, it is desirable to use 2-isopropoxy-4, 4, 5, 5-tetramethyl-1, 3, 2-dioxaborolane.

  The terminal functionalization reaction is preferably performed in the presence of a solvent. As such a solvent, the same solvents as exemplified in the halogenation reaction can be used, and two or more kinds may be used in combination. The amount of the solvent used is preferably 1 to 100 parts by weight and more preferably 1 to 50 parts by weight with respect to 1 part by weight of the intermediate. Moreover, it does not specifically limit about the reaction temperature at the time of making a terminal functionalizing agent react, It is preferable that it is the range of -100-100 degreeC. When reaction temperature is less than -100 degreeC, there exists a possibility that reaction rate may become very slow, and it is more preferable that it is -80 degreeC or more. On the other hand, when reaction temperature exceeds 100 degreeC, there exists a possibility of accelerating | stimulating decomposition | disassembly of a product, It is more preferable that it is 50 degrees C or less, and it is still more preferable that it is 0 degrees C or less. The reaction time is preferably 1 minute to 20 hours, and more preferably 0.5 to 5 hours. The reaction pressure is preferably 0 to 3 MPa (gauge pressure).

  The terminal functionalization reaction is preferably performed in the presence of a base catalyst. As the base to be used, an organic lithium compound is suitable. Examples of the organic lithium compound include alkyllithium compounds such as methyllithium, n-butyllithium, sec-butyllithium, and tert-butyllithium; aryllithium compounds such as phenyllithium; alkenyllithium compounds such as vinyllithium; lithium diisopropylamide And lithium amide compounds such as lithium bistrimethylsilylamide. Among these, it is preferable to use an alkyl lithium compound. It does not specifically limit about the usage-amount of an organolithium compound, It is preferable that it is 0.5-5 mol with respect to 1 mol of intermediate bodies. When the amount of the organolithium compound used exceeds 5 mol, there is a risk of promoting side reactions and product decomposition.

  The π-electron conjugated polymer of the present invention having a repeating unit represented by the chemical formula (2) is represented by the dithiophene compound (monomer) represented by the chemical formula (1) and the following chemical formula (3) in the presence of a catalyst. The monomer can be produced by alternating copolymerization with a so-called coupling reaction.

M ^p2 -Ar-M ^p2 (3)

In the chemical formula (2), X and R ^{1 to} R ⁴ are synonymous with the chemical formula (1). In the chemical formulas (2) and (3), Ar is a divalent group including a (hetero) aromatic ring which may have a substituent. In chemical formula (3), M ^p2 each independently represents a halogen atom, a boronic acid, a boronic acid ester, —MgY, —ZnY, and —SnR ^a ₃ (wherein R ^a is a linear alkyl group having 1 to 4 carbon atoms, Y is one selected from the group consisting of halogen atoms. Here, M ^p1 and M ^p2 included in each of the dithiophene compound represented by the chemical formula (1) and the monomer represented by the chemical formula (3) are different from each other. That is, when M ^p1 is a halogen atom, M ^p2 is one selected from the group consisting of boronic acid, boronic acid ester, —MgY, —ZnY, and —SnR ^a ₃ (wherein Y and R ^a are the same as above). . Conversely, when M ^p2 is a halogen atom, M ^p1 is one selected from the group consisting of boronic acid, boronic ester, —MgY, —ZnY, and —SnR ^a ₃ (wherein Y and R ^a are the same as above). is there. Examples of the halogen atom used for Y include fluorine, chlorine, bromine and iodine.

In the dithiophene compound of the present invention represented by the chemical formula (1) and the π-electron conjugated polymer (2) of the present invention, the alkyl group used in R ^{1 to} R ⁴ is a linear or branched alkyl group, Alternatively, it may be a cyclic cycloalkyl group. For example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, isopentyl group, neopentyl group, tert-pentyl group, linear or branched alkyl groups such as n-hexyl group, isohexyl group, 2-ethylhexyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decyl group, dodecyl group; cyclopropyl group, Examples thereof include cycloalkyl groups such as a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclononyl group, a cyclodecyl group, a cycloundecyl group, and a cyclododecyl group. Among these, an alkyl group having 3 or more carbon atoms is preferable from the viewpoint of easy synthesis and excellent solubility. The upper limit of the carbon number is not particularly limited, but 20 or less is preferable from the viewpoint of solubility. In addition, carbon number here means the carbon number except the substituent illustrated below.

The alkyl group in R ^{1 to} R ⁴ may have a substituent. Examples of the substituent include aryl groups such as a phenyl group, a naphthyl group, an anthryl group, and a phenanthryl group; a pyridyl group, a thienyl group, and a furyl group. , Pyrrolyl group, imidazolyl group, pyrazinyl group, oxazolyl group, thiazolyl group, pyrazolyl group, benzothiazolyl group, benzoimidazolyl group, and the like; methoxy group, ethoxy group, n-propyloxy group, isopropoxy group, n-butoxy group , Isobutoxy group, sec-butoxy group, tert-butoxy group, pentyloxy group, isopentyloxy group, neopentyloxy group, n-hexyloxy group, cyclohexyloxy group, heptyloxy group, n-octyloxy group, nonyloxy group , N-decyloxy group, n-dodecy Alkoxy groups such as oxy group; alkylthio groups such as methylthio group, ethylthio group, propylthio group and butylthio group; arylthio groups such as phenylthio group and naphthylthio group; methoxycarbonyl group, ethoxycarbonyl group, propoxycarbonyl group, isopropoxycarbonyl group, alkoxycarbonyl groups such as n-butoxycarbonyl group, isobutoxycarbonyl group, sec-butoxycarbonyl group, tert-butoxycarbonyl group, pentyloxycarbonyl group, hexyloxycarbonyl group, heptyloxycarbonyl group, octyloxycarbonyl group; Alkyl sulfenyl groups such as sulfoxide groups and ethyl sulfoxide groups; Aryl sulfoxide groups such as phenyl sulfoxide groups; Methyl sulfonyloxy , Sulfonic acid ester groups such as ethylsulfonyloxy group, phenylsulfonyloxy group, methoxysulfonyl group, ethoxysulfonyl group, phenyloxysulfonyl group; dimethylamino group, diphenylamino group, methylphenylamino group, methylamino group, ethylamino group Primary or secondary amino group such as: methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, substituted with acetyl group, benzoyl group, benzenesulfonyl group, tert-butoxycarbonyl group, etc. an amino group optionally substituted with an alkyl group such as a tert-butyl group or a phenyl group or an aryl group; a cyano group; a nitro group; a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom or an iodine atom; It is done. Among these, from the viewpoint of expanding the π-conjugated system of the main skeleton, an aryl group such as a phenyl group or a naphthyl group, or a heteroaryl group such as a pyridyl group or a thienyl group is preferable.

Examples of the aryl group used in R ^{1 to} R ⁴ include a phenyl group, a naphthyl group, an anthryl group, and a phenanthryl group. These aryl groups may have a substituent, and as such a substituent, a substituent other than the aryl group exemplified in the description of the alkyl group, the above-described alkyl group, and the like can be used.

Examples of the heteroaryl group used in R ^{1 to} R ⁴ include a pyridyl group, a thienyl group, a furyl group, a pyrrolyl group, an imidazolyl group, a pyrazinyl group, an oxazolyl group, a thiazolyl group, a pyrazolyl group, a benzothiazolyl group, and a benzoimidazolyl group. It is done. These heteroaryl groups may have a substituent, and as such a substituent, a substituent other than the heteroaryl group exemplified in the description of the alkyl group, the above-described alkyl group, and the like can be used. .

  X in chemical formula (1) and chemical formula (2) is selected from the group consisting of carbon, silicon and germanium and may be the same or different. Among these, silicon or germanium is preferable from the viewpoint of thermal stability.

  Ar in chemical formula (1) and chemical formula (2) is a divalent group containing a (hetero) aromatic ring which may have a substituent. For example, a monocyclic (hetero) aromatic ring which may have a substituent, a divalent group including a condensed (hetero) aromatic ring which may have a substituent, or a monocyclic (hetero) aromatic ring and a condensed ring Examples thereof include a polycyclic (hetero) aromatic group in which a plurality of ring (hetero) aromatic rings are linked.

Examples of the divalent group containing a monocyclic (hetero) aromatic ring which may have a substituent include a hydrogen atom from a benzene ring, a thiophene ring, a thiazole ring, a pyridine ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, etc. And a divalent group obtained by removing two of the above. Specific examples are shown in the following chemical formulas (a) to (g). Of these, a thiophene-2,5-diyl group obtained by removing two hydrogen atoms from a thiophene ring is preferable.

Examples of the divalent group containing a condensed (hetero) aromatic ring which may have a substituent include groups represented by the following chemical formulas (h) to (u). The number of aromatic rings contained in the condensed (hetero) aromatic ring is preferably 2 to 7.

  Among these divalent groups containing a condensed (hetero) aromatic ring, a condensed heteroaromatic ring such as the structure shown in (k), (l), (m), (t) or (u) A divalent group is preferred.

Examples of the polycyclic (hetero) aromatic group in which a plurality of monocyclic (hetero) aromatic rings and condensed (hetero) aromatic rings are linked include groups represented by the following chemical formulas (v1) to (v9). . These may have a substituent.

In the chemical formula, R ⁵ and R ^{5 ′} are each independently a hydrogen atom, a fluorine atom, or a linear, branched or cyclic hydrocarbon group having 1 to 20 carbon atoms which may have a substituent. Yes, this hydrocarbon group may be interrupted by an oxygen atom or a sulfur atom. R ⁵ and R ^{5 ′} may form a ring. R ⁶ , R ^{6 ′} and R ^{6a to} R ^6d are each independently a hydrogen atom or a linear, branched or cyclic hydrocarbon group having 1 to 20 carbon atoms which may have a substituent, This hydrocarbon group may be interrupted by an oxygen atom or a sulfur atom. R ⁶ , R ^{6 ′} and R ^{6a to} R ^6h may form a ring. R ⁷ and R ^{7 ′} are each independently a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent, and this hydrocarbon group may be interrupted by an oxygen atom or a sulfur atom. R ⁸ and R ^{8 ′} are each independently a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent, and this hydrocarbon group may be interrupted by an oxygen atom or a sulfur atom. R ⁸ and R ^{8 ′} may form a ring. R ⁹ and R ^{9 ′} are each independently a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent. R ¹⁰ and R ^{10 ′} are each independently a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent. R ¹¹ is a hydrogen atom or a halogen atom.

In the chemical formula, p is the number of substituents R ⁵ and is 0, 1, 2, or 3. q represents the number of thiophene rings contained in Ar, and is 1, 2 or 3.

で示される、化学式（１）で示されるジチオフェン化合物由来の縮環複素環基に対して電子吸引性の基であることが好ましい。すなわち、化学式（２）で示される繰り返し単位を有するπ電子共役重合体は、縮環複素環基が相対的に電子供与性であり、Ａｒが相対的に電子吸引性であるローバンドギャップポリマーであることが、光電変換効率の観点から好ましい。ローバンドギャップポリマーは、より長波長側の光を吸収し電気エネルギーに変換できるため、光電変換特性が向上する。本発明のπ電子共役重合体は、単量体である化学式（１）で示されるジチオフェン化合物のＨＯＭＯ準位が低く、電子供与性が強いため、Ａｒ基と組み合わせることで深いＨＯＭＯ準位を有するローバンドギャップポリマーとすることができる。それゆえ、光電変換素子の活性層として用いた場合に、高い電流と電圧を発現し、高い光電変換効率を発揮することができる。電子吸引性の強さは、Ａｒを構成する構造に電子リッチなヘテロ原子を有する割合から推測することができる。すなわち、酸素、窒素、硫黄、ケイ素、りんなどのヘテロ原子を相対的に多く有するＡｒは電子吸引性が強いと判断することができる。 Ar in the chemical formula (2) represents the following chemical formula (5)

It is preferably an electron-withdrawing group with respect to the condensed heterocyclic group derived from the dithiophene compound represented by the chemical formula (1). That is, the π-electron conjugated polymer having the repeating unit represented by the chemical formula (2) is a low band gap polymer in which the condensed heterocyclic group is relatively electron donating and Ar is relatively electron withdrawing. Is preferable from the viewpoint of photoelectric conversion efficiency. Since the low band gap polymer can absorb light on a longer wavelength side and convert it into electric energy, the photoelectric conversion characteristics are improved. The π-electron conjugated polymer of the present invention has a deep HOMO level when combined with an Ar group because the dithiophene compound represented by chemical formula (1), which is a monomer, has a low HOMO level and a strong electron donating property. It can be a low band gap polymer. Therefore, when used as an active layer of a photoelectric conversion element, a high current and voltage can be expressed and high photoelectric conversion efficiency can be exhibited. The strength of electron withdrawing can be inferred from the proportion of hetero atoms rich in electrons in the structure constituting Ar. That is, it can be determined that Ar having a relatively large number of heteroatoms such as oxygen, nitrogen, sulfur, silicon, and phosphorus has a strong electron-withdrawing property.

  As Ar, among those exemplified above, a divalent group containing a condensed (hetero) aromatic ring which may have a substituent or a monocyclic (hetero) aromatic ring and a condensed (hetero) aromatic ring It is preferably a polycyclic (hetero) aromatic ring group connected in plural, and more preferably a group containing a heteroaromatic ring having two or more heteroatoms in the ring. In particular, a structure represented by the chemical formula (k), (l), (m), (t), (u), (v1), (v5), (v6) or (v9) is preferable.

In the π-electron conjugated polymer of the present invention, a preferred structure of the repeating unit represented by the chemical formula (2) is shown below.

(Wherein R ^{1 to} R ⁷ and R ¹¹ are as defined above)
Examples of the substituent that R ^{5 to} R ¹⁰ may have include, for example, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-bull group, and a tert-butyl group. Group, n-pentyl group, isopentyl group, neopentyl group, tert-pentyl group, n-hexyl group, isohexyl group, 2-ethylhexyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decyl group Alkyl groups such as cyclopropyl group, cyclopentyl group, cyclohexyl group and cyclooctyl group; aryl groups such as phenyl group, naphthyl group, pyridyl group, thienyl group, furyl group and pyrrolyl group; methoxy group, ethoxy group and n-propyl group Oxy group, isopropyloxy group, n-butoxy group, n-hexyl group, cyclohexyloxy group, n-octyl Alkoxy groups such as ruoxy group, n-decyloxy group and n-dodecyloxy group; alkylthio groups such as methylthio group, ethylthio group, propylthio group, butylthio group, phenylthio group and naphthylthio group; methoxycarbonyl group, ethoxycarbonyl group, n- Alkoxycarbonyl groups such as butoxycarbonyl group; sulfoxide groups such as methyl sulfoxide group, ethyl sulfoxide group, and phenyl sulfoxide group; methyl sulfonyloxy group, ethyl sulfonyloxy group, phenyl sulfonyloxy group, methoxy sulfonyl group, Sulfonic acid ester groups such as ethoxysulfonyl group and phenyloxysulfonyl group; dimethylamino group, diphenylamino group, methylphenylamino group, methylamino group, ethylamino group, etc. Primary or secondary amino group; methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-, substituted with acetyl group, benzoyl group, benzenesulfonyl group, tert-butoxycarbonyl group, etc. An amino group optionally substituted with an alkyl group such as a butyl group or a phenyl group or an aryl group; a cyano group; a nitro group, and the like.

  The degree of polymerization of the π-electron conjugated polymer of the present invention is not particularly limited as long as the requirements of the present invention are satisfied, but is preferably 2,000 or less from the viewpoint of dissolving in an organic solvent to obtain a uniform solution. Moreover, it is preferable that it is 5 or more from a viewpoint of obtaining a homogeneous organic thin film, and it is more preferable that it is 15 or more.

  Further, the π-electron conjugated polymer of the present invention may be composed of the same monomer unit as long as it has the repeating unit represented by the chemical formula (2), and the effect of the present invention is impaired. As long as it is not, another monomer unit may be contained. Any of a homopolymer, a random copolymer, or a block copolymer may be used. The molecular chain may be linear, branched, physically or chemically cross-linked.

  It is preferable to use a transition metal complex as a catalyst for the coupling reaction in producing the π-electron conjugated polymer (2) of the present invention having a repeating unit represented by the chemical formula (2). Usually, transition metal complexes belonging to groups 3 to 10 of the periodic table (Group 18 long-period type periodic table), especially 8 to 10 are listed. Specifically, known complexes such as Ni, Pd, Ti, Zr, V, Cr, Co, and Fe can be used. Of these, Ni complexes and Pd complexes are preferable. Moreover, as a ligand of the complex to be used, tridentate phosphine coordination such as trimethylphosphine, triethylphosphine, triisopropylphosphine, tri-t-butylphosphine, tricyclohexylphosphine, triphenylphosphine, tris (2-methylphenyl) phosphine Diphenylphosphinomethane (dppm), 1,2-diphenylphosphinoethane (dppe), 1,3-diphenylphosphinopropane (dppp), 1,4-diphenylphosphnobutane (pdbb), 1,3- Bidentate phosphine compounds such as bis (dicyclohexylphosphino) propane (dcpp), 1,1′-bis (diphenylphosphino) ferrocene (dppf), 2,2-dimethyl-1,3-bis (diphenylphosphino) propane Lico; tetramethyl ester Diamine, bipyridine, such as a nitrogen-containing ligands such as acetonitrile can be preferably used.

  In addition, although the usage-amount of a complex changes with pi electron conjugated polymers to manufacture, 0.001-0.1 mol is preferable with respect to a monomer. When there are too many catalysts, it will cause the molecular weight fall of the polymer obtained. It is also economically disadvantageous. On the other hand, when there are too few catalysts, reaction rate will become slow and stable production will become difficult.

In addition to the dithiophene compound represented by the chemical formula (1) and the monomer represented by the chemical formula (3), the π-electron conjugated polymer of the present invention has the following chemical formula (4).
A-M ^q (4)
It is also possible to manufacture using the compound shown below (it may abbreviate as a terminal blocker hereafter). A is an arbitrary aryl group. M ^q is composed of a halogen atom, boronic acid, boronic ester, -MgY, -ZnY, -SiY ₃ and -SnR ^a ₃ (where R ^a is a linear alkyl group having 1 to 4 carbon atoms and Y is a halogen atom). One selected from the group.

  The π-electron conjugated polymer of the present invention is preferably produced in the presence of a solvent. The solvent that can be used for the production needs to be selected depending on the type of the π-electron conjugated polymer to be produced, but a commercially available solvent can be generally selected. Examples of the solvent used here include tetrahydrofuran, 2-methyltetrahydrofuran, 1,4-dioxane, dimethyl ether, ethyl methyl ether, diethyl ether, dipropyl ether, butyl methyl ether, t-butyl methyl ether, dibutyl ether, cyclopentyl. Ether solvents such as methyl ether and diphenyl ether; aliphatic or alicyclic saturated hydrocarbon solvents such as pentane, hexane, heptane and cyclohexane; aromatic hydrocarbon solvents such as benzene, toluene and xylene; Alkyl halide solvents; aromatic aryl halide solvents such as chlorobenzene and dichlorobenzene; solvents such as dimethylformamide, diethylformamide and N-methylpyrrolidone De solvents; such as water and mixtures thereof. The amount of the solvent used is preferably in the range of 1 to 1000 times the mass of the monomer of the π-electron conjugated polymer to be produced. Among these, from the viewpoint of the solubility of the obtained π-electron conjugated polymer and the stirring efficiency of the reaction solution, it is more preferably 10 times by mass or more, and more preferably 100 times by mass or less from the viewpoint of reaction rate.

  In this invention, although superposition | polymerization temperature changes with kinds of (pi) electron conjugated polymer to manufacture, it is the range of -80 degreeC-200 degreeC normally. In the present invention, the pressure of the reaction system is not particularly limited, but is preferably from 0.1 to 10 atm, and more preferably at about 1 atm. The reaction time is preferably 20 minutes to 150 hours.

  The π-electron conjugated polymer represented by the chemical formula (2) is reacted by usual operations such as reprecipitation, solvent removal under heating, solvent removal under reduced pressure, removal of solvent with steam (steam stripping), and the like. It can be isolated and obtained from a solution. The crude product thus obtained can be purified by washing or extraction using a commercially available solvent using a Soxhlet extractor.

  Examples of the solvent used here include ether solvents such as tetrahydrofuran, 2-methyltetrahydrofuran, 1,4-dioxane, dimethyl ether, and ethyl methyl ether; aliphatic or alicyclic saturation such as pentane, hexane, heptane, and cyclohexane. Hydrocarbon solvents; aromatic hydrocarbon solvents such as benzene, toluene and xylene; ketone solvents such as acetone, ethyl methyl ketone and diethyl ketone; alkyl halide solvents such as dichloromethane and chloroform; chlorobenzene and dichlorobenzene Aromatic aryl halide solvents; amide solvents such as dimethylformamide, diethylformamide, N-methylpyrrolidone; water and mixtures thereof.

  The number average molecular weight of the π-electron conjugated polymer is preferably 1,000 to 1,000,000 g / mol, and preferably 5,000 to 200,000 g / mol from the viewpoints of processability, crystallinity, solubility, photoelectric conversion characteristics, and the like. It is more preferable that If the number average molecular weight is too high, the solubility is lowered, and the workability of a thin film or the like may be lowered. On the other hand, if the number average molecular weight is too low, the crystallinity, film stability, photoelectric conversion characteristics and the like may be deteriorated.

  Here, the number average molecular weight means the number average molecular weight in terms of polystyrene by gel permeation chromatography (hereinafter sometimes referred to as GPC). The number average molecular weight of the π-electron conjugated polymer of the present invention can be determined by ordinary GPC using a solvent such as tetrahydrofuran (THF), chloroform, dimethylformamide (DMF) and the like. However, some of the π-electron conjugated polymers of the present invention have low solubility around room temperature. In such a case, the number average molecular weight may be determined by high-temperature GPC chromatography using dichlorobenzene, trichlorobenzene or the like as a solvent. .

The HOMO level of the π electron conjugated polymer of the present invention is preferably −5.0 eV or less. When the HOMO level of the π-electron conjugated polymer is −5.0 eV or less, an organic photoelectric conversion element using the HOMO level as a photoelectric conversion active layer can obtain a high voltage (V _oc ) of _0.70 V or more. It becomes possible. A material having a low HOMO level also has an advantage of excellent oxidation resistance. The HOMO level used in the present invention refers to the ionization energy obtained by photoelectron yield spectroscopy using a thin film having a thickness of 100 nm or more obtained by dissolving a π-electron conjugated polymer in an organic solvent and casting on a glass substrate. It shall be calculated from the value.

  The π-electron conjugated polymer of the present invention can be used as an organic semiconductor material taking advantage of the above characteristics. In particular, it is useful for organic semiconductor devices such as thin-film organic transistors, organic EL elements, and photoelectric conversion elements.

  The organic semiconductor composition containing the π-electron conjugated polymer in the present invention is not particularly limited as long as it contains the π-electron conjugated polymer of the present invention, organic semiconductor materials other than the present invention, solvents, crystallization agents, It includes compositions with antioxidants, various forms of metal materials, inorganic crystals and so on. When the π-electron conjugated polymer of the present invention is formed by a coating process, it may be in the form of a solution containing at least one component that can dissolve the π-electron conjugated polymer.

  The composition containing the π-electron conjugated polymer of the present invention may be a solution to which a poor solvent is added in order to improve the crystallinity of the polymer, and improves the stability of the π-electron conjugated polymer of the present invention. A stabilizer such as an antioxidant may be included for the purpose. A thin film after the above solution is formed by various coating methods and the solvent is distilled off is also included in the composition of the present invention. Moreover, when using the composition containing the pi electron conjugated polymer of this invention for an organic photoelectric conversion element, you may contain the electron-accepting semiconductor.

  As an example of an organic semiconductor device containing the π-electron conjugated polymer of the present invention having a repeating unit represented by the chemical formula (2), a photoelectric conversion element is preferably exemplified. Hereinafter, description will be given with reference to the drawings.

  A preferred embodiment of the photoelectric conversion element is shown in FIG. The photoelectric conversion element 20 includes a positive electrode 25 which is a transparent electrode, a hole transport layer 24 which is an arbitrary smooth layer, a photoelectric conversion active layer 23 containing a π electron conjugated polymer, and an arbitrary smooth layer on a substrate 26. An electron transport layer 22 and a negative electrode 21 are sequentially stacked. In the example of FIG. 1, the substrate 26 side is a positive electrode 25 that is a transparent electrode, and the side far from the substrate is a negative electrode 21 that is a counter electrode. The structure of the photoelectric conversion element 20 is not limited to these, and the positive electrode and the negative electrode, the hole transport material, and the electron transport material may be interchanged depending on the characteristics of the material.

  The π-electron conjugated polymer of the present invention can be used for the photoelectric conversion active layer 23 of the photoelectric conversion element 20 by forming an organic semiconductor composition with an electron-accepting material. The electron-accepting material constituting the composition is not particularly limited as long as it is an organic material exhibiting n-type semiconductor characteristics. For example, 1,4,5,8-naphthalenetetracarboxylic dianhydride (NTCDA), 3,4 , 9,10-perylenetetracarboxylic dianhydride (PTCDA), N, N′-dioctyl-3,4,9,10-naphthyltetracarboxydiimide (NTCDI-C8H), 2- (4-biphenylyl) -5 Oxazole derivatives such as (4-t-butylphenyl) -1,3,4-oxadiazole and 2,5-di (1-naphthyl) -1,3,4-oxadiazole; 3- (4-biphenylyl) ) -4-azole-5- (4-tert-butylphenyl) -1,2,4-triazole and other triazole derivatives; phenanthroline derivatives , C60, C70 and the like fullerene derivatives; carbon nanotubes (CNT), poly-p-phenylene vinylene-based polymers introduced with a cyano group (CN-PPV), and the like. These may be used alone or in combination of two or more. Among these, fullerene derivatives are preferably used from the viewpoint of an n-type semiconductor that is stable and excellent in carrier mobility.

  The fullerene derivatives include unsubstituted ones such as C60, C70, C76, C78, C82, C84, C90, and C94, and [6,6] -phenyl C61 butyric acid methyl ester ([6,6]- C61-PCBM), [5,6] -phenyl C61 butyric acid methyl ester, [6,6] -phenyl C61 butyric acid n-butyl ester, [6,6] -phenyl C61 butyric acid i-butyl ester [6,6] -phenyl C61 butyric acid hexyl ester, [6,6] -phenyl C61 butyric acid dodecyl ester, [6,6] -diphenyl C62 bis (butyric acid methyl ester) ([6,6 ] -C62-bis-PCBM), [6,6] -phenyl C71 And substituted derivatives, including Ji butyric acid methyl ester ([6,6] -C71-PCBM) and the like.

  The ratio of the electron-accepting material in the composition is preferably 10 to 1000 parts by mass, and more preferably 50 to 500 parts by mass with respect to 100 parts by mass of the π-electron conjugated polymer of the present invention. .

  The composition may contain other components such as a surfactant, a binder resin, a metal, and a filler as long as the object of the present invention is not impaired.

  The mixing method of the π-electron conjugated polymer and the electron-accepting material of the present invention is not particularly limited, but after adding to the solvent in a desired ratio, one method such as heating, stirring, and ultrasonic irradiation is used. Alternatively, a method may be mentioned in which a plurality of types are combined and dissolved in a solvent to form a solution.

  Although it does not specifically limit as a solvent, It is preferable from a viewpoint on organic thin film forming to use the solvent whose solubility in 20 degreeC is 1 mg / mL or more about each of the (pi) electron conjugated polymer and electron-accepting material of this invention. When the solubility is 1 mg / mL or less, it is difficult to produce a homogeneous organic thin film, and the composition of the present invention cannot be obtained. Furthermore, from the viewpoint of arbitrarily controlling the film thickness of the organic thin film, it is more preferable to use a solvent having a solubility at 20 ° C. of 3 mg / mL or more for each of the π-electron conjugated polymer and the electron-accepting material of the present invention. .

  Examples of the solvent include tetrahydrofuran, 1,2-dichloroethane, cyclohexane, chloroform, bromoform, benzene, toluene, o-xylene, chlorobenzene, bromobenzene, iodobenzene, o-dichlorobenzene, anisole, methoxybenzene, trichlorobenzene, pyridine, and the like. Is mentioned. These solvents may be used singly or in combination of two or more types, and in particular, o-dichlorobenzene, chlorobenzene, bromobenzene having high solubility of the π electron conjugated polymer and the electron accepting material of the present invention. , Iodobenzene, chloroform and mixtures thereof are preferred. More preferably, o-dichlorobenzene, chlorobenzene and a mixture thereof are used.

  The composition solution may contain an additive having a boiling point higher than that of the solvent in addition to the π-electron conjugated polymer and the electron-accepting material of the present invention. In the process of forming an organic thin film by adding an additive, a fine and continuous phase separation structure of the π-electron conjugated polymer and the electron-accepting material of the present invention is formed, so that photoelectric conversion is excellent in photoelectric conversion efficiency. The active layer 23 can be obtained. Examples of the additive include octanedithiol (boiling point: 270 ° C.), dibromooctane (boiling point: 272 ° C.), diiodooctane (boiling point: 327 ° C.) and the like.

  The addition amount of the additive is not particularly limited as long as the π-electron conjugated polymer and the electron-accepting material of the present invention do not precipitate and give a uniform solution. It is preferably 1% to 20%. When the additive amount is less than 0.1%, a sufficient effect cannot be obtained to form a fine and continuous phase separation structure. When the additive amount is more than 20%, The drying speed becomes slow and it becomes difficult to obtain a homogeneous organic thin film. More preferably, it is in the range of 0.5% to 10%.

  The film thickness of the organic photoelectric conversion layer 23 is usually 1 nm to 1 μm, preferably 2 nm to 1000 nm, more preferably 5 nm to 500 nm, and further preferably 20 nm to 300 nm.

  The method for coating the solution containing the π-electron conjugated polymer and the electron-accepting material of the present invention on a substrate or a support is not particularly limited, and a conventionally known coating using a liquid coating material. Any of the methods can be employed. For example, dip coating method, spray coating method, ink jet method, aerosol jet method, spin coating method, bead coating method, wire bar coating method, blade coating method, roller coating method, curtain coating method, slit die coater method, gravure coater method , Slit reverse coater method, micro gravure method, comma coater method, etc. can be adopted, and the coating method can be selected according to the coating film properties to be obtained, such as coating thickness control and orientation control. That's fine.

  The organic photoelectric conversion layer 23 may be further subjected to thermal annealing as necessary. Thermal annealing is performed by holding the substrate on which the organic thin film is formed at a desired temperature. Thermal annealing may be performed under reduced pressure or in an inert gas atmosphere, and a preferable temperature is 40 ° C to 300 ° C, more preferably 70 ° C to 200 ° C. If the temperature is low, a sufficient effect cannot be obtained. If the temperature is too high, the organic thin film is oxidized and / or decomposed, and sufficient photoelectric conversion characteristics cannot be obtained.

  The substrate 26 on which the photoelectric conversion element 20 is formed may be any substrate that does not change when the electrode or the organic photoelectric conversion layer 23 is formed. For example, inorganic materials such as alkali-free glass and quartz glass, metal films such as aluminum, and any organic material such as polyester, polycarbonate, polyolefin, polyamide, polyimide, polyphenylene sulfide, polyparaxylene, epoxy resin and fluorine resin Films and plates produced by the method can be used. When a transparent substrate is used, the substrate-side electrode is preferably transparent or translucent. Although the film thickness of the board | substrate 26 is not specifically limited, Usually, it is the range of 1 micrometer-10 mm.

  In the said photoelectric conversion element 20, it is preferable that any one of the positive electrode 25 and the negative electrode 21 has a light transmittance. The light transmittance of the electrode is not particularly limited as long as incident light reaches the organic photoelectric conversion layer 23 and an electromotive force is generated. The thickness of the electrode may be in a range having light transparency and conductivity, and is preferably 20 nm to 300 nm, although it varies depending on the electrode material.

  Examples of the electrode material having optical transparency include a conductive metal oxide film and a translucent metal thin film. Specifically, indium oxide, zinc oxide, tin oxide, and their composites, indium tin oxide (ITO), fluorine tin oxide (FTO), antimony tin oxide, indium zinc oxide A film made using a conductive material made of (IZO), gallium / zinc / oxide, aluminum / zinc / oxide, antimony / zinc / oxide, or an ultrathin film of gold, platinum, silver, or copper is used. Of these, ITO, FTO, IZO, and tin oxide are preferable. Examples of the method for producing the electrode include a vacuum deposition method, a sputtering method, an ion plating method, and a plating method. Moreover, you may use organic transparent electrically conductive films, such as polyaniline and its derivative (s), polythiophene, and its derivative (s) as a transparent electrode material.

  As the counter electrode material, a known metal, a conductive polymer, or the like can be used, and it may not have optical transparency, and may be transparent or translucent. Preferably, one of the pair of electrodes is preferably made of a material having a low work function. For example, metals such as lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, strontium, barium, aluminum, scandium, vanadium, zinc, yttrium, indium, cerium, samarium, europium, terbium, ytterbium, and two of them One or more alloys, or one or more of them, and an alloy of one or more of gold, silver, platinum, copper, manganese, titanium, cobalt, nickel, tungsten, tin, graphite, or a graphite intercalation compound are used. It is done.

  Examples of the alloy include magnesium-silver alloy, magnesium-indium alloy, magnesium-aluminum alloy, indium-silver alloy, lithium-aluminum alloy, lithium-magnesium alloy, lithium-indium alloy, calcium-aluminum alloy, and the like.

  The electrode used for the photoelectric conversion element of the present invention preferably uses a conductive material having a high work function on one side and a conductive material having a low work function on the other side. At this time, an electrode using a conductive material having a high work function is a positive electrode, and an electrode using a conductive material having a low work function is a negative electrode.

  In the photoelectric conversion element 20, a hole transport layer 24 may be provided between the positive electrode 25 and the organic photoelectric conversion layer 23 as necessary. The material for forming the hole transport layer 24 is not particularly limited as long as it has p-type semiconductor characteristics. However, the polythiophene polymer, the polyaniline polymer, the poly-p-phenylene vinylene polymer, and the polyfluorene polymer are not particularly limited. Conductive polymers such as polymers, low molecular organic compounds exhibiting p-type semiconductor properties such as phthalocyanine derivatives (H2Pc, CuPc, ZnPc, etc.), porphyrin derivatives, metal oxides such as molybdenum oxide, zinc oxide, and vanadium oxide. Preferably used. The thickness of the hole transport layer 24 is preferably 1 nm to 600 nm, and more preferably 20 nm to 300 nm.

  When the hole transport layer 24 is formed between the positive electrode 25 and the organic photoelectric conversion layer 23, for example, in the case of a conductive polymer soluble in a solvent, a dip coating method, a spray coating method, an ink jet method, an aerosol jet Method, spin coating method, bead coating method, wire bar coating method, blade coating method, roller coating method, curtain coating method, slit die coater method, gravure coater method, slit reverse coater method, micro gravure method, comma coater method, etc. Can be applied. When using a low molecular weight organic material such as a phthalocyanine derivative or a porphyrin derivative, it is preferable to apply a vapor deposition method using a vacuum vapor deposition machine. Further, the electron transport layer 22 described below can be similarly produced.

  In the photoelectric conversion element 20, an electron transport layer 22 may be provided between the negative electrode 21 and the organic photoelectric conversion layer 23 as necessary. The material for forming the electron transport layer 22 is not particularly limited as long as it has n-type semiconductor characteristics, but the above-described electron-accepting materials (NTCDA, PTCDA, NTCDI-C8H, oxazole derivatives, triazole derivatives, phenanthroline derivatives, Fullerene derivatives, CNT, CN-PPV, etc.) are preferably used. The thickness of the electron transport layer 22 is preferably 1 nm to 600 nm, and more preferably 5 nm to 100 nm.

  In the photoelectric conversion element 20, a metal fluoride may be provided as a buffer layer that further facilitates charge transfer between the negative electrode 21 and the organic photoelectric conversion layer 23. Examples of the metal fluoride include lithium fluoride, sodium fluoride, potassium fluoride, magnesium fluoride, calcium fluoride, cesium fluoride, and particularly preferably lithium fluoride and cesium fluoride. The buffer layer preferably has a thickness of 0.05 nm to 50 nm, more preferably 0.5 nm to 20 nm. The buffer layer may be used in combination with the electron transport layer 22 described above, and when used in combination, the buffer layer is preferably formed on the electrode side.

  The photoelectric conversion element thus formed may be used as a tandem photoelectric conversion element. The tandem photoelectric conversion element in the present invention can be produced by a method known in the literature, for example, a method described in Science, 2007, Vol. 317, pp222. Specifically, a structure in which a charge recombination layer is sandwiched between an active layer (1) produced using the organic semiconductor composition of the present invention and an active layer (2) capable of photoelectric conversion in a different absorption band. The connection order of the active layer (1) and the active layer (2) may be reversed.

  The charge recombination layer functions to recombine electrons generated in the active layer on the positive electrode side and holes generated in the active layer on the negative electrode side. Holes and electrons generated by charge separation in each active layer move toward the positive electrode and the negative electrode, respectively, by an internal electric field in the active layer. At this time, holes generated in the active layer on the positive electrode side and electrons generated in the active layer on the negative electrode side are taken out to the positive electrode and the negative electrode, respectively, and electrons generated on the active layer on the positive electrode side and the negative electrode side Recombination of holes generated in the active layer causes each active layer to function as a battery in which the active layers are electrically connected in series, increasing the open circuit voltage.

  The charge recombination layer preferably has optical transparency so that a plurality of active layers can absorb light. In addition, the charge recombination layer only needs to be designed so that holes and electrons are sufficiently recombined. Therefore, the charge recombination layer does not necessarily have to be a film. For example, the charge recombination layer is a metal cluster uniformly formed on the active layer. It does not matter. Therefore, the charge recombination layer includes a very thin metal film or metal cluster made of gold, platinum, chromium, nickel, lithium, magnesium, calcium, tin, silver, aluminum or the like and having a light transmittance of several nm or less. (Including alloys), ITO, IZO, AZO, GZO, FTO, highly light-transmitting metal oxide films and clusters such as titanium oxide and molybdenum oxide, polyethylene dioxythiophene with added polystyrene sulfonic acid (PSS) ( A conductive organic material film such as PEDOT, or a composite of these is used.

  For example, uniform silver clusters can be formed by depositing silver so as to be several nm or less on a quartz oscillator film thickness monitor using a vacuum deposition method. In addition, if a titanium oxide film is formed, the sol-gel method described in, for example, Advanced Materials, 2006, Vol. 18, pp572 may be used. If it is a composite metal oxide such as ITO or IZO, the film may be formed by sputtering. These charge recombination layer formation methods and types may be appropriately selected in consideration of the non-destructive property to the active layer when forming the charge recombination layer, the formation method of the active layer to be laminated next, and the like.

  The photoelectric conversion element 20 can be applied to various photoelectric conversion devices using a photoelectric conversion function, an optical rectification function, and the like. For example, it is useful for photovoltaic cells (such as solar cells), electronic devices (such as optical sensors, optical switches, phototransistors), optical recording materials (such as optical memories), and the like.

  Examples of the present invention will be described in detail below, but the present invention is not limited to these examples. In addition, the physical-property measurement and refinement | purification of the (pi) electron conjugated polymer of this invention manufactured at each said process and the following process were performed as follows.

(Weight average molecular weight (Mw) / Number average molecular weight (Mn))
A number average molecular weight and a weight average molecular weight are calculated | required by the polystyrene conversion value based on the measurement by a gel permeation chromatography (GPC). In the present invention, HLC-8020 (product number) manufactured by Tosoh Corporation was used as the GPC apparatus. When tetrahydrofuran (THF) was used as the eluent, ShoF KF804 was connected in series when the column was used as an eluent, and TSKgel Multipore HZ manufactured by Tosoh Corporation was connected in series when chloroform was used as the eluent. A thing was used.

(Identification of molecular structure)
The molecular structure of the obtained compound was identified by measuring ¹ H ( ¹³ C as required) -NMR (nuclear magnetic resonance). In the present invention, a superconducting nuclear magnetic resonance apparatus Varian 400-MR (manufactured by Varian) is used as an apparatus, a sample is dissolved in deuterated chloroform at a concentration of 20 mg / mL, filtered through a 0.45 μm PTFE filter, and then 25 ° C. Measured with The number of integration is 128 times for the monomer and 12800 times for the polymer.

(HOMO level analysis)
The HOMO level of the π-electron conjugated polymer was analyzed by photoelectron yield spectroscopy. In the present invention, an ionization energy measuring device BIP-KV201 (manufactured by Spectrometer Co., Ltd.) is used as an apparatus, and a thin film having a thickness of 100 nm or more obtained by dissolving a π electron conjugated polymer in an organic solvent and casting on a glass substrate is used. It was calculated from the value of ionization energy obtained in the above.

  Prior to the production of the π-electron conjugated polymer of the present invention, synthesis examples 1 to 4 of monomers represented by the chemical formula (1) on which the polymer is based are shown. All reactions were performed in dry argon. 3,3′-Dibromo-5,5′-bis (trimethylsilyl) -2,2′-bithiophene (Organometallics 1999, 18, 1453-1459) and 1,2-dichlorotetrabutyldisilane (Organometallics, 1993, Vol. 12, 2078-2084) were synthesized according to methods described in the literature. Other reagents used were commercial products.

(Synthesis Example 1)
The synthesis of the compound represented by the following chemical formula (6) is shown below. In the following chemical formula, Bu represents an n-butyl group.

  7.03 g (15 mmol) of 3,3′-dibromo-5,5′-bis (trimethylsilyl) -2,2′-bithiophene was dried in a 200 mL three-necked flask equipped with a stirrer, a condenser, and a dropping funnel. 150 mL of THF was added and dissolved by stirring at room temperature, and then cooled to -80 ° C. Subsequently, 18 mL (30 mmol) of n-butyllithium was dropped from the dropping funnel over 1.5 hours. After confirming the disappearance of the raw materials and the formation of the lithiated product by gas chromatography, 5.34 g of 1,2-dichlorotetrabutyldisilane was added dropwise over 0.5 hour from the dropping funnel, gradually returned to room temperature and stirred overnight. Thereafter, the reaction solution was added to a similar volume of ice water, and the organic layer was extracted with hexane. The organic layer was dried over magnesium sulfate, purified on a column using hexane as a developing solvent using silica gel pretreated with hexamethyldisilazane, and 4.64 g (7.8 mmol) of the target compound represented by the chemical formula (10). ) (Yield 52%).

(Identification result)
¹ H NMR: δ 0.33 (s, 18H, (CH ₃ ) ₃ Si-), 0.77-0.94 (m, 20H, (( CH ₃ CH ₂ CH ₂ CH ₂ ) ₂ Si) _2- ), 1.26-1.37 ( m, 16H, ((CH ₃ CH ₂ CH ₂ CH ₂ ) ₂ Si) _2- ), 7.13 (s, 2H, thiophen)
¹³ C NMR: δ 0.05, 12.50, 13.70, 26.60, 27.05, 133.77, 138.05, 140.32, 150.92.
The analysis result supports the chemical structure of chemical formula (6).

(Synthesis Example 2)
The synthesis of the compound represented by the following chemical formula (7) is shown below.

  To a 100 mL two-necked flask equipped with a stirrer and a condenser, 4.27 g (7.2 mmol) of the compound represented by the chemical formula (10) and 72 mL of dry chloroform were added. After immersing the flask in an ice bath and cooling to 0 ° C., 2.56 g (14 mmol) of N-bromosuccinimide was added in several portions and stirred for 1 hour. Thereafter, the reaction solution was washed with water and an aqueous sodium thiosulfate solution. After liquid separation, it was dried with magnesium sulfate. After removing the solvent, purification with a silica gel column pretreated with hexamethyldisilazane using hexane as a developing solvent gave 4.02 g (6.6 mmol) of the target compound represented by the chemical formula (11) (yield) 79%).

(Identification result)
¹ H NMR: δ 0.75-0.92 (m, 20H, (( CH ₃ CH ₂ CH ₂ CH ₂ ) ₂ Si) _2- ), 1.25-1.34 (m, 16H, ((CH ₃ CH ₂ CH ₂ CH ₂ ) ₂ Si) _2- ), 6.95 (s, 2H, thiophen)
¹³ C NMR: δ 12.31, 13.62, 26.55, 26.92, 110.11, 134.65, 135.64, 145.98.
The analysis result supports the chemical structure of chemical formula (7).

(Synthesis Example 3)
The synthesis of the compound represented by the following chemical formula (8) is shown below.

To a 50 mL three-necked flask equipped with a stirrer, a condenser tube, and a dropping funnel, 1.23 g (2.0 mmol) of the compound represented by the chemical formula (11) and 20 mL of dry diethyl ether were added and cooled to −80 ° C. From the dropping funnel, 2.4 mL (4.0 mmol) of n-butyllithium was added dropwise over 15 minutes. After stirring for 1 hour, 0.88 g (4.4 mmol) of trimethyltin chloride was added and the temperature was gradually returned to room temperature, followed by stirring overnight. Thereafter, the reaction solution was added to about the same volume of ice water and extracted with hexane. The organic layer was dried over magnesium sulfate and purified by recycle GPC using toluene as a developing solvent to obtain 1.08 g (1.4 mmol) of the target compound represented by the chemical formula (12) (yield 70%).

(Identification result)
¹ H NMR: δ 0.37 (s, 18H, (CH ₃ ) ₃ Sn-), 0.78-0.95 (m, 20H, (( CH ₃ CH ₂ CH ₂ CH ₂ ) ₂ Si) _2- ), 1.29-1.35 ( m, 16H, ((CH ₃ CH ₂ CH ₂ CH ₂ ) ₂ Si) _2- ), 7.09 (s, 2H, thiophen)
¹³ C NMR: δ -8.09, 12.60, 13.70, 26.63, 27.08, 132.89, 135.28, 141.33, 151.64.
The analysis result supports the chemical structure of chemical formula (8).
Next, Example 1 of the present invention for synthesizing the π-electron conjugated polymer represented by the chemical formula (2) from the monomer represented by the chemical formula (1) is shown.

Example 1
Synthesis of a polymer represented by the following chemical formula (9)

  In a 30 mL two-necked flask equipped with a stirrer and a condenser, 0.38 g (0.5 mmol) of the compound (12) represented by the chemical formula (12), 4,7-dibromo-2,1,3-benzothiadiazole 0.15 g (0.5 mmol), tri (o-tolyl) phosphine 0.3 g (0.1 mmol), tris (dibenzylideneacetone) dipalladium (0) 0.23 g (0.025 mmol), dry toluene Was added and stirred. After repeating freeze degassing-argon substitution of the reaction solution, the reaction solution was heated to 50 ° C. and stirred for 3 days. After completion of the reaction, an aqueous solution in which 3.1 g of sodium diethyldithiocarbamate trihydrate was dissolved in 30 mL of water was added to the reaction solution, and the mixture was stirred at 85 ° C. for 2 hours. Subsequently, 200 mL of toluene was added to separate the reaction solution, and the organic layer was washed with water and 3% aqueous acetic acid and then dried over magnesium sulfate. After the solvent was distilled off, the residue was purified by reprecipitation to obtain 0.12 g (yield 24%) of the desired π electron conjugated polymer.

(Identification result)
¹ H NMR: δ 0.97-1.67 (br m, 40H, Bu), 7.17-7.71 (br m, 2H, thiophene), 8.50 (br s, 2H, benzothiaziazole)
The analysis result supports the chemical structure of chemical formula (9).

撹拌子、冷却管を備えた３０ｍＬ二口フラスコに、上記式（１２）で示される化合物（１２）を０．２００ｇ（０．２５８ｍｍｏｌ）、４，７−ビス（５−ブロモ−２−チエニル）−２，１，３−ベンゾチアジアゾールを０．１１８ｇ（０．２５８ｍｍｏｌ）、トリ（ｏ−トリル）ホスフィンを０．０１６ｇ（０．０５２ｍｍｏｌ）、トリス（ジベンジリデンアセトン）ジパラジウム（０）を０．０１９ｇ（０．０１３ｍｍｏｌ）、乾燥トルエンを１５ｍＬ加え、攪拌した。反応液の凍結脱気−アルゴン置換を繰り返した後、反応液を７０℃に加熱し、３日間撹拌した。反応終了後、反応液にナトリウムジエチルジチオカーバメート３水和物３．１ｇを３０ｍＬの水に溶解させた水溶液を加え、８５℃で２時間撹拌した。続いてトルエン２００ｍＬを加えて反応液を分液し、有機層を水と３％酢酸水で洗浄した後に、硫酸マグネシウムで乾燥した。溶媒を留去した後、残渣を再沈殿により精製し、目的のπ電子共役重合体０．１９ｇを得た。 As a result of molecular weight measurement by the THF elution system GPC, Mn = 10,200, Mw = 29,500, and polydispersity (Mw / Mn) = 2.88. As a result of measuring the ionization energy, the HOMO level in the solid thin film was −5.2 eV.
(Example 2)
Synthesis of a polymer represented by the following chemical formula (10)

In a 30 mL two-necked flask equipped with a stirrer and a condenser tube, 0.200 g (0.258 mmol) of the compound (12) represented by the above formula (12), 4,7-bis (5-bromo-2-thienyl) 0.118 g (0.258 mmol) of 2,1,3-benzothiadiazole, 0.016 g (0.052 mmol) of tri (o-tolyl) phosphine, and 0.03 of tris (dibenzylideneacetone) dipalladium (0). 019 g (0.013 mmol) and 15 mL of dry toluene were added and stirred. After repeating freeze degassing-argon substitution of the reaction solution, the reaction solution was heated to 70 ° C. and stirred for 3 days. After completion of the reaction, an aqueous solution in which 3.1 g of sodium diethyldithiocarbamate trihydrate was dissolved in 30 mL of water was added to the reaction solution, and the mixture was stirred at 85 ° C. for 2 hours. Subsequently, 200 mL of toluene was added to separate the reaction solution, and the organic layer was washed with water and 3% aqueous acetic acid and then dried over magnesium sulfate. After distilling off the solvent, the residue was purified by reprecipitation to obtain 0.19 g of the target π electron conjugated polymer.

(Identification result)
¹ H NMR: δ = 0.91-1.54 (br m, Bu), 7.19-7.71 (br m, thiophene), 7.99-8.15 (br m, benzothiadiazole)

  As a result of molecular weight measurement by chloroform elution system GPC, Mn = 13,200, Mw = 33,200, and polydispersity (Mw / Mn) = 2.52. As a result of measuring the ionization energy, the HOMO level in the solid thin film was −5.1 eV.

(Comparative Example 1)
Synthesis of a polymer represented by the following chemical formula (11) without applying the present invention

  An alternating copolymer of dithienosilol and benzothiadiazole was synthesized. A detailed procedure for the synthesis of the polymer of the chemical formula (11) is described in Non-Patent Document 2.

  As a result of molecular weight measurement by THF elution system GPC, Mn = 12,400, Mw = 25,600, and polydispersity (Mw / Mn) = 2.06. As a result of measuring the ionization energy, the HOMO level in the solid thin film was -4.9 eV.

  The HOMO levels calculated from the ionization energies of the solid thin films of the polymers obtained in Examples 1 and 2 and Comparative Example 1 are shown in the table.

  As can be seen from the above table, the π-electron conjugated polymer of the present invention has a lower HOMO level than the π-electron conjugated polymer obtained in the comparative example.

(Creation of photoelectric conversion element)
3.0 mg of the π-electron conjugated polymer obtained in Example 1 and 6.0 mg of PC71BM (E110 manufactured by Frontier Carbon Co.) as an electron-accepting material and 2.5 vol% of 1,8-diiodooctane as a solvent. The resulting mixture was mixed with 0.25 mL of chlorobenzene at 100 ° C. for 6 hours. Thereafter, the mixture was cooled to 20 ° C. and filtered through a PTFE filter having a pore size of 1.0 μm to prepare a composition solution containing the π-electron conjugated polymer of the present invention and PC ₇₁ BM. A composition solution containing PC71BM was also produced by the same method for the π-electron conjugated polymer obtained in Comparative Example 1.

  A glass substrate provided with an ITO film (resistance value 10Ω / □) with a thickness of 150 nm by sputtering was subjected to surface treatment by ozone UV treatment for 15 minutes. A PEDOT: PSS aqueous solution (manufactured by Heraeus: CLEVIOS P VP AI4083) serving as a hole transport layer was formed on the substrate to a thickness of 30 nm by a spin coating method, and dried by heating at 140 ° C. for 20 minutes using a hot plate. Next, the above composition solution was applied by spin coating and vacuum dried for 3 hours to form a photoelectric conversion layer (film thickness of about 90 nm) as a thin film. Next, lithium fluoride was vapor-deposited with a film thickness of 0.5 nm by vacuum vapor deposition, and then Al was vapor-deposited with a film thickness of 100 nm. Thereby, each photoelectric conversion element containing each polymer obtained in Example 1 and Comparative Example 1 was produced. The light receiving surface shape of the photoelectric conversion element was a regular square of 5 × 5 mm.

(Photoelectric conversion characteristics evaluation)
The photoelectric conversion efficiency was measured under the following measurement conditions using a solar simulator and a source meter. The irradiation intensity at the time of measurement was adjusted to be a solar cell evaluation standard using a photodiode (BS-520, manufactured by Spectrometer Co., Ltd.). At the time of measurement, an irradiation light mask having the same area as the light receiving area of the photoelectric conversion element was worn to eliminate excessive light incidence.
<Measurement conditions>
Solar simulator: PEC-L11 (Peccell Technology)
Source meter: KEITHLEY2400 (manufactured by KEITHLEY)
Irradiation spectrum: AM1.5
Irradiation intensity: 100 mW / cm ²
Light receiving area: 0.25 cm ²

When the photoelectric conversion characteristic of the photoelectric conversion element produced using the π-electron conjugated polymer of Example 1 was measured, J _sc = 12.69 mA / cm ² , V _oc = 0.82 V, FF = 0.60, The photoelectric conversion efficiency was 6.24%.

When the photoelectric conversion characteristic of the photoelectric conversion element produced using the π-electron conjugated polymer of Comparative Example 1 was measured, J _sc = 10.79 mA / cm ² , V _oc = 0.68 V, FF = 0.51, The photoelectric conversion efficiency was 3.74%.

Regarding Example 2, a photoelectric conversion element was prepared in the same manner as in Example 1, and the photoelectric conversion characteristics were measured. As a result, V _oc = 0.72V.

As can be seen from the comparison between the photoelectric conversion element using the π-electron conjugated polymer of the present invention shown in the examples and the photoelectric conversion element using the π-electron conjugated polymer shown in the comparative example, a book with a low HOMO level. By using the π-electron conjugated polymer of the invention, a high V _oc is expressed in the photoelectric conversion element, and as a result, a photoelectric conversion element having high photoelectric conversion efficiency can be obtained.

  20 is a photoelectric conversion element, 21 is a negative electrode, 22 is an electron transport layer, 23 is a photoelectric conversion active layer, 24 is a hole transport layer, 25 is a positive electrode, and 26 is a substrate.

Claims (11)

A dithiophene compound represented by the following chemical formula (1).

(Wherein R ¹ , R ² , R ³ and R ⁴ each independently have a hydrogen atom, a fluorine atom, a C 1-20 alkyl group which may have a substituent, or a substituent. The aryl group having 6 to 20 carbon atoms or the heteroaryl group having 4 to 20 carbon atoms which may have a substituent may be the same or different, and X is selected from carbon, silicon and germanium, and may be the same or different. M ^p1 is independently a halogen atom, boronic acid, boronic acid ester, —MgY, —ZnY, and —SnR ^a ₃ (wherein R ^a is a linear alkyl group having 1 to 4 carbon atoms, Y is a halogen atom) Selected from atoms)) A π-electron conjugated polymer having a repeating unit represented by the following chemical formula (2) and having a number average molecular weight of 1,000 to 1,000,000 g / mol.

(In formula, R < ¹ >, R < ² >, R < ³ > and R < ⁴ > may have the same or different hydrogen atom, fluorine atom, C1-C20 alkyl group which may have a substituent, and a substituent. An aryl group having 6 to 20 carbon atoms or an optionally substituted heteroaryl group having 4 to 20 carbon atoms, X is an element selected from carbon, silicon and germanium, and Ar is a substituent. (It is a divalent group containing a (hetero) aromatic ring which may be present.) The π-electron conjugated polymer according to claim ² , wherein R ¹ , R ² , R ^3, and R ⁴ are each independently a C 1-20 alkyl group that may have a substituent.   The π-electron conjugated polymer according to claim 2 or 3, wherein each X is independently silicon or germanium.   The Ar is a divalent group including a monocyclic (hetero) aromatic ring which may have a substituent and / or a condensed (hetero) aromatic ring which may have a substituent. The π-electron conjugated polymer according to any one of the above. The π-electron conjugated polymer according to claim 5, wherein Ar is a divalent group containing at least one (hetero) aromatic ring selected from the following chemical formulas (a) to (u).

(Wherein R ⁵ and R ^{5 ′} are each independently a hydrogen atom, a fluorine atom, or a linear, branched or cyclic hydrocarbon group having 1 to 20 carbon atoms which may have a substituent. The hydrocarbon group may be interrupted by an oxygen atom or a sulfur atom, etc. R ⁵ and R ^{5 ′} may form a ring, and R ⁶ and R ^{6 ′} are each independently a hydrogen atom. Alternatively, it may be a linear, branched or cyclic hydrocarbon group having 1 to 20 carbon atoms which may have a substituent, and this hydrocarbon group may be interrupted by an oxygen atom or a sulfur atom. , R ^{6, R} 6 ^'good .R ⁷ and R ⁷ may form a ^ring' is a hydrocarbon group each independently carbon atoms which may have a substituent 1 to 20, the hydrocarbon good .R ⁸ and R ⁸ be interrupted by such groups is an oxygen atom or a sulfur atom ^'are each independently Substituted hydrocarbon group which may having 1 to 20 carbon atoms, the hydrocarbon group may be interrupted by an oxygen atom and a sulfur atom. Also, R ⁸ and R ^{8 'is} a ring are each independently also be .R ⁹ and R ^{9 'is} a .R ¹⁰ and R ¹⁰ hydrocarbon group each independently carbon atoms which may have a hydrogen atom or substituent having 1 to ^20' and (It is a C1-C20 hydrocarbon group which may have a substituent. R ¹¹ is a hydrogen atom or a halogen atom.)   The organic-semiconductor composition containing the pi-electron conjugated polymer in any one of Claims 2-6.   An organic semiconductor device comprising the π-electron conjugated polymer according to claim 2.   It is a photoelectric conversion element, The organic-semiconductor device of Claim 8 characterized by the above-mentioned.   The photoelectric conversion element which has a layer containing the (pi) electron conjugated polymer in any one of Claims 2-6, and an electron-accepting material.   A tandem photoelectric conversion element comprising the photoelectric conversion element according to claim 9.

Images