JP2008106239A - Organic photoelectric conversion element and polymer useful for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a compound having both excellent charge transport properties and solubility in an organic solvent. <P>SOLUTION: The polymer comprises a repeating unit A composed of one structure represented by formula (1) (wherein ring A and ring B are each a benzene ring; R<SP>1</SP>and R<SP>2</SP>are each a hydrogen atom, an alkyl group, an alkoxy group or an aryl group with the proviso that at least one R<SP>1</SP>and R<SP>2</SP>is the alkyl group), one specific thiophene structure and one or more thiophene structures containing no substituent group in which the difference between the maximum number of carbons in the carbon main chain contained in the alkyl group represented by R<SP>1</SP>and/or R<SP>2</SP>and the maximum number of carbons in the carbon main chain contained in the alkyl group in the specific thiophene structure is 0 or 1. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an organic photoelectric conversion device and a polymer useful for the production thereof.

Organic semiconductor materials having charge (electron, hole) transportability are expected to be applied to organic electroluminescence elements, organic transistors, and organic photoelectric conversion elements (organic solar cells, optical sensors, etc.), and various studies have been made.
As an organic semiconductor material, a material having high charge transportability is required from the viewpoint of improving the performance of an organic photoelectric conversion element. Furthermore, this organic semiconductor material is desired to have excellent solubility in an organic solvent from the viewpoint that an organic photoelectric conversion element can be produced at low cost by coating.
In order to improve the charge transport property of the organic semiconductor material, it is important to use a compound having a π-conjugate spread, improve the packing between molecules, and enhance the interaction between molecules. From this viewpoint, various aromatic ring compounds have been studied. Specifically, in order to increase the planarity of the molecule, various compounds in which thiophenes are linked have been studied. For example, fluorene-co-bithiophene exhibiting high hole transportability has been proposed (Non-patent Document 1). However, fluorene-co-bithiophene has a problem of low solubility in organic solvents. Therefore, further studies have been made to improve solubility, and fluorene-co-pentathiophene with improved solubility has been proposed (Non-patent Document 2).

H. Sirringhaus et al .: Science, 2000, Vol.290, 2123. Brennan, David J et al .: Mat. Res. Soc. Symp. Proc., 2004. 814.

However, the solubility of fluorene-co-pentathiophene is not sufficient, and the development of a compound excellent in both charge transportability and solubility in an organic solvent has been desired.
Then, an object of this invention is to provide the compound excellent in both charge transport property and the solubility to an organic solvent.

（式中、Ａ環及びＢ環は、それぞれ独立に、置換基を有していてもよいベンゼン環を表し、該ベンゼン環上に結合手を有する。Ｒ¹、Ｒ²、Ｒ³及びＲ⁴は、それぞれ独立に、水素原子、直鎖状若しくは分岐状の炭素数１〜２０のアルキル基、炭素数１〜２０のアルコキシ基、又は炭素数６〜６０のアリール基を表す。これらの基は、一部又は全部の水素原子がフッ素原子で置換されていてもよい。該アリール基は、置換基を有していてもよい。但し、Ｒ¹及びＲ²の少なくとも一方は該アルキル基であり、Ｒ³及びＲ⁴の少なくとも一方は該アルキル基である。） In the present invention, first, one structure represented by the following formula (1), one structure represented by the following formula (2), and one or two structures represented by the following formula (3) are represented. It is a polymer containing a repeating unit consisting of two or more (repeating unit A), and is represented by the maximum number of carbons in the carbon main chain contained in the alkyl group represented by R ¹ or R ² , and R ³ or R ^4. The polymer is characterized in that the difference from the maximum carbon number of the carbon main chain contained in the alkyl group is 0 or 1.

(In the formula, A ring and B ring each independently represent a benzene ring which may have a substituent, and have a bond on the benzene ring. R ¹ , R ² , R ³ and R ⁴ Each independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or an aryl group having 6 to 60 carbon atoms. A part or all of the hydrogen atoms may be substituted with fluorine atoms, and the aryl group may have a substituent, provided that at least one of R ¹ and R ² is the alkyl group. , R ³ and R ⁴ are the alkyl group.)

  Secondly, the present invention provides a composition containing the polymer.

  Third, the present invention provides a pair of electrodes, at least one of which is transparent or translucent, a first organic layer containing an electron-accepting compound provided between the electrodes, and adjacent to the first organic layer. And an organic photoelectric conversion device having a second organic layer containing an electron donating compound, wherein the electron donating compound is the polymer. .

  Fourthly, the present invention provides an organic photoelectric conversion device having a pair of electrodes, at least one of which is transparent or translucent, and at least one organic layer provided between the electrodes and containing an electron-accepting compound and an electron-donating compound. An organic photoelectric conversion element is provided, wherein the electron donating compound is the polymer.

  Fifthly, the present invention provides an organic thin film solar cell module and an organic image sensor in which a plurality of the organic photoelectric conversion elements are integrated.

  The polymer of the present invention is excellent in both charge transportability and solubility in an organic solvent. Therefore, it is particularly useful for the production of organic semiconductors, organic photoelectric conversion elements, organic thin film solar cell modules, organic image sensors and the like. And the organic semiconductor manufactured using the polymer of this invention, an organic photoelectric conversion element, an organic thin film solar cell module, an organic image sensor, etc. are excellent in charge transport property. In addition, since the polymer of the present invention has high solubility in an organic solvent (particularly, high solubility in an organic solvent at a temperature near room temperature (10 ° C. to 50 ° C.)), the coating method is used. It is also advantageous in that it can be applied to produce an organic layer (or organic thin film) having a uniform film quality. Furthermore, the polymer of this invention is excellent also in photoelectric conversion efficiency, when it applies to an organic photoelectric conversion element.

Hereinafter, the present invention will be described in detail with reference to the drawings as necessary. In the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. Further, the positional relationship such as up, down, left and right is as shown in the drawings unless otherwise specified, but the dimensional ratio of the drawings is not limited. Further, in this specification, when “C ₆ H ₁₃ ”, “C ₈ H ₁₇ ” and the like are simply described, it means “n-C ₆ H ₁₃ ” and “n-C ₈ H ₁₇ ”.

<Polymer>
The polymer of the present invention has one structure represented by the formula (1), one structure represented by the formula (2), and one or two structures represented by the formula (3). It is a polymer containing a repeating unit consisting of two or more (repeating unit A), and is represented by the maximum number of carbons in the carbon main chain contained in the alkyl group represented by R ¹ or R ² , and R ³ or R ^4. The difference from the maximum carbon number of the carbon main chain contained in the alkyl group is 0 or 1.

  Since a polymer having such a repeating unit has a thiophene ring structure, the π-conjugated planarity between the rings is good. Further, by introducing a substituent, the polymer is chemically stable and excellent in solubility in an organic solvent.

  In the repeating unit A, the structure represented by the formula (3) preferably has 3 to 6, more preferably 4 to 6.

  In the present specification, the “maximum carbon number of the carbon main chain contained in the alkyl group” means the number of all carbons constituting the linear alkyl group, and is the longest in the branched alkyl group (ie, Means the number of carbons constituting the straight-chain part. For example, in a 2-ethylhexyl group, the hexyl group is the longest linear portion, and the number of carbons constituting this is 6.

  In the formula (1), in the benzene ring optionally having a substituent represented by A ring and B ring, the substituent is a linear, branched or cyclic alkyl having 1 to 20 carbon atoms. Group, an alkoxy group having 1 to 20 carbon atoms containing the alkyl group in the structure thereof, and a linear, branched or cyclic alkyl group having 1 to 12 carbon atoms is preferable.

In the formulas (1) and (2), the linear or branched alkyl group having 1 to 20 carbon atoms represented by R ¹ , R ² , R ³ and R ⁴ includes a methyl group, an ethyl group, n-propyl group, iso-propyl group, n-butyl group, iso-butyl group, tert-butyl group, 3-methylbutyl group, pentyl group, hexyl group, 2-ethylhexyl group, heptyl group, octyl group, nonyl group, Although a decyl group, a lauryl group, etc. are mentioned, a C1-C10 alkyl group is preferable and a pentyl group, a hexyl group, 2-ethylhexyl group, an octyl group, and a decyl group are more preferable. Some or all of the hydrogen atoms in the alkyl group may be substituted with fluorine atoms.

Formula (1), (2), R ^1, R ^2, as the alkoxy group of R ³ and having 1 to 20 carbon atoms represented by R ^4, which said alkyl group and an oxygen atom is bonded Is mentioned. Some or all of the hydrogen atoms in the alkoxy group may be substituted with fluorine atoms.

In the formulas (1) and (2), examples of the aryl group having 6 to 60 carbon atoms represented by R ¹ , R ² , R ³ and R ⁴ include a phenyl group and a C _{1 to} C ₁₂ alkoxyphenyl group. (“C ₁ -C ₁₂ alkoxy” indicates that the alkoxy moiety has 1 to 12 carbon atoms. The same applies to the following.), C ₁ -C ₁₂ alkylphenyl group (“C ₁ -C ₁₂ alkyl”) "Indicates that the alkyl moiety has 1 to 12 carbon atoms. The same applies to the following.), 1-naphthyl group, 2-naphthyl group and the like, and aryl groups having 6 to 20 carbon atoms are preferred. C ₁ -C ₁₂ alkoxyphenyl group and C ₁ -C ₁₂ alkylphenyl group are more preferred. The aryl group may have a substituent. Examples of the substituent include a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, and an alkoxy group having a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms in its structure. And a linear, branched or cyclic alkyl group having 1 to 12 carbon atoms is preferable. Some or all of the hydrogen atoms in the aryl group may be substituted with fluorine atoms.

From the viewpoint of solubility in an organic solvent, in the formulas (1) and (2), at least one of R ¹ and R ² is the alkyl group, and at least one of R ³ and R ⁴ is the alkyl group. .

As R < ¹ > -R < ⁴ > in said Formula (1), (2), a C5-C20 linear or branched alkyl group is preferable from a viewpoint of improving the charge transport property as an organic semiconductor, R More preferably, all of ^{1 to} R ⁴ are the alkyl group. In particular, from the viewpoint of increasing the solubility, it is preferable that both R ¹ and R ² are branched alkyl groups.

In the repeating unit A, from the viewpoint of improving charge transportability, it is preferable that two or three structures represented by the formula (3) are continuous, represented by the following formula (7) or (8). It is more preferable that a structure represented by the following formula (7) is formed.

  In addition, from the viewpoint of improving the planarity of the structure connected to the structure represented by the formula (2), at least one of the bonds in the structure represented by the formula (2), particularly both, It is preferable that the structure represented by Formula (3) is connected.

（式中、Ｒ³及びＲ⁴は前記のとおりであり、ｍ及びｎは、それぞれ独立に、１〜３の整数を表す。但し、ｍとｎとの和は３〜６の整数である。） From the above viewpoint, in the repeating unit A, the structure represented by the formula (2) and the structure represented by the formula (3) are integrated into a structure represented by the following formula (9). It is preferable to form.

(In the formula, R ³ and R ⁴ are as defined above, and m and n each independently represent an integer of 1 to ^3. However, the sum of m and n is an integer of 3 to 6. )

  In the formula (9), m and n are preferably each independently 2 or 3, and the sum of m and n is more preferably an integer of 4-6. Moreover, it is preferable that m and n are the same.

  The polymer of the present invention is represented by the formula (2) from the viewpoint of enhancing the planarity when the structure represented by the formula (2) and the structure represented by the formula (3) are connected. The structure and the structure represented by the formula (3) preferably include a repeating unit having a structure in which 4 or more in total are connected, and more preferably include a repeating unit having a structure in which 5 or more are connected. By increasing the planarity in this way, the packing between molecules is improved, the interaction between molecules can be increased, and the charge transport property is improved. On the other hand, from the viewpoint of increasing the solubility of the polymer of the present invention in an organic solvent, it is preferable that four or more structures represented by the formula (3) are not connected in the repeating unit A.

  In addition, the polymer of the present invention has a structure represented by the formula (1) in the repeating unit A from the viewpoint of improving the planarity between the structure represented by the formula (1) and the structure connected thereto. It is preferable that the structure represented by the formula (3) is connected to at least one of the bonds, particularly both.

  In the polymer of the present invention, the repeating unit A may be included singly or in combination of two or more. Moreover, it is preferable that the polymer of this invention contains at least one repeating unit which consists of one structure represented by said Formula (1), and one structure represented by said Formula (9).

（式中、Ｒ³及びＲ⁴は前記と同じである。） Specific examples of the structure represented by the formula (9) include those represented by the following formulas (I) to (V). From the viewpoint of improving charge transportability, the structure is represented by the following formula (II). Those are preferred. In these specific examples, those in which R ³ and R ⁴ are alkyl groups are preferred.

(In the formula, R ³ and R ⁴ are the same as described above.)

（式中、Ｅ環及びＦ環は、それぞれ独立に、置換基を有していてもよいベンゼン環又は置換基を有していてもよいナフタレン環を表し、該置換基を有していてもよいベンゼン環又は置換基を有していてもよいナフタレン環上に結合手を有する。Ｒ¹¹、Ｒ¹²、Ｒ¹³及びＲ¹⁴は、それぞれ独立に、水素原子、炭素数１〜２０のアルキル基、炭素数１〜２０のアルコキシ基、又は炭素数６〜６０のアリール基を表す。これらの基は、一部又は全部の水素原子がフッ素原子で置換されていてもよい。該アリール基は、置換基を有していてもよい。但し、Ｒ¹³及びＲ¹⁴の少なくとも一方は水素原子でない。また、Ｅ環及びＦ環がベンゼン環であり、かつ、Ｒ¹¹及びＲ¹²の少なくとも一方がアルキル基であり、Ｒ¹³及びＲ¹⁴の少なくとも一方がアルキル基である場合、Ｒ¹¹又はＲ¹²で表されるアルキル基に含まれる炭素主鎖の最大炭素数と、Ｒ¹³又はＲ¹⁴で表されるアルキル基に含まれる炭素主鎖の最大炭素数との差が２以上である。） Furthermore, the polymer of the present invention may contain other repeating units, and from the viewpoint of enhancing solubility in organic solvents and charge transportability, one structure represented by the following formula (10), It is preferable that one of the structures represented by formula (11) and one or more of the structures represented by formula (3) include a repeating unit (repeating unit B). On the other hand, in view of ease of production, it is preferable to include only a repeating unit having a structure represented by the formulas (1) to (3). Moreover, in the polymer of this invention, the repeating unit B may be contained individually by 1 type, or may be contained in combination of 2 or more types.

(In the formula, each of the E ring and the F ring independently represents a benzene ring which may have a substituent or a naphthalene ring which may have a substituent, and may have the substituent. R ¹¹ , R ¹² , R ¹³ and R ¹⁴ each independently represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, which has a bond on a good benzene ring or an optionally substituted naphthalene ring. Represents an alkoxy group having 1 to 20 carbon atoms or an aryl group having 6 to 60 carbon atoms, in which some or all of the hydrogen atoms may be substituted with fluorine atoms. It may have a substituent, provided that at least one of R ¹³ and R ¹⁴ is not a hydrogen atom, the E ring and the F ring are benzene rings, and at least one of R ¹¹ and R ¹² is alkyl. a group, at least one of alkyl of R ¹³ and R ¹⁴ If it is, the maximum number of carbon atoms in the carbon backbone constituting the alkyl group represented by R ¹¹ or R ^12, the maximum number of carbon atoms in the carbon backbone constituting the alkyl group represented by R ¹³ or R ¹⁴ The difference is 2 or more.)

  In the formula (10), the benzene ring which may have a substituent represented by the E ring and the F ring, and the substituent of the naphthalene ring which may have a substituent include an A ring and a B ring. This is the same as explained and exemplified in the section of the benzene ring which may have a substituent represented by:

Formula (10), (11) in, R ^11, R ^12, the alkyl group of R ¹³ and having 1 to 20 carbon atoms represented by R ^14, alkoxy group having 1 to 20 carbon atoms, and having 1 to 60 carbon atoms, Is an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, and an aryl group having 6 to 60 carbon atoms represented by R ¹ , R ² , R ³ and R ^4. Same as described and illustrated. Furthermore, the alkyl group includes a cyclic alkyl group, and examples thereof include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclononyl group, and a cyclododecyl group.

When these repeating units (that is, other repeating units such as the repeating unit B) are included, the ratio of the repeating unit A to the total repeating units in the polymer of the present invention is preferably 50 mol% or more (50 ~ 100 mol%), more preferably more than 50 mol%,
More preferably, it is 80 mol% or more (80-100 mol%), Most preferably, it is 80-95 mol%.

（式中、Ｒ¹、Ｒ²、Ｒ³及びＲ⁴は、前記と同じである。Ｒ⁷及びＲ⁸は、それぞれ独立に、水素原子、直鎖状又は分岐状の炭素数１〜２０のアルキル基、炭素数１〜２０のアルコキシ基、又は炭素数６〜６０のアリール基を表す。前記アリール基は置換基を有していてもよい。複数存在するＲ⁷及びＲ⁸は、同一であっても異なっていてもよい。） As a specific example of the polymer of the present invention, one containing a repeating unit represented by the following formula (VI) is preferable from the viewpoint of enhancing solubility in an organic solvent and charge transporting property.

(In the formula, R ¹ , R ² , R ³ and R ⁴ are the same as described above. R ⁷ and R ⁸ are each independently a hydrogen atom, linear or branched C 1-20. Represents an alkyl group, an alkoxy group having 1 to 20 carbon atoms, or an aryl group having 6 to 60 carbon atoms, wherein the aryl group may have a substituent, and a plurality of R ⁷ and R ⁸ are the same. It may or may not be.)

In the above formula, a linear or branched alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, and an aryl group having 6 to 60 carbon atoms represented by R ⁷ and R ⁸ are R ^1, R ^2, R ^3, linear or branched alkyl group having 1 to 20 carbon atoms represented by R ^4, section alkoxy group, and aryl group having 6 to 60 carbon atoms having 1 to 20 carbon atoms This is the same as described and exemplified in.

  When the polymer of the present invention is used for the production of an organic photoelectric conversion device, if the polymerization active group remains as it is in the terminal group, the durability and the like of the resulting device may be deteriorated. It is preferable to protect with a group.

  Examples of the terminal group include a hydrogen atom, an alkyl group, an alkoxy group, a fluoroalkyl group, a fluoroalkoxy group, an aryl group, a heterocyclic group, an electron donating group, an electron withdrawing group, and the like from the viewpoint of improving hole transportability. An arylamino group or an electron donating group is preferred. In addition, as the terminal group, those having a conjugated bond continuous with the conjugated structure of the main chain are also preferable, and examples thereof include those bonded to an aryl group or a heterocyclic group via a carbon-carbon bond. .

（式中、Ｒ及びＲ’は、それぞれ独立に、末端基を表す。ｐ及びｑは、それぞれ独立に２〜１００００の整数である。該式で表される化合物がオリゴマーである場合には、２〜９の整数であることが好ましく、該式で表される化合物がポリマーである場合には、１０〜２０００の整数、特には１０〜２００の整数であることが好ましい。各式中の二つの＊は、相互に結合している状態を意味する。） As the polymer of the present invention, those represented by the following formulas (X) to (XVIII) are particularly preferable.

(In the formula, R and R ′ each independently represent a terminal group. P and q are each independently an integer of 2 to 10000. When the compound represented by the formula is an oligomer, It is preferably an integer of 2 to 9, and when the compound represented by the formula is a polymer, it is preferably an integer of 10 to 2000, particularly preferably an integer of 10 to 200. * Means that they are connected to each other.)

  In the above formula, the terminal groups represented by R and R ′ are the same as those described above, but a phenyl group, an arylamino group, and an electron donating group are preferable.

The number average molecular weight in terms of polystyrene of the polymer of the present invention is preferably 10 ³ to 10 ⁸ , more preferably 10 ³ to 10 ⁶ , and still more preferably 10 ³ to 10 ⁵ .

<Method for producing polymer>
The method for producing the polymer of the present invention is not particularly limited and may be produced by any method, but is preferably produced by the following production method.

（式中、Ａ環、Ｂ環、Ｇ環及びＨ環、Ｒ¹〜Ｒ⁴、Ｒ¹⁵〜Ｒ¹⁸、ｍ及びｎは、前記と同じである。Ｗ¹及びＷ²は、それぞれ独立に、ハロゲン原子、アルキルスルホネート基、アリールスルホネート基、アリールアルキルスルホネート基、ホウ酸エステル残基、スルホニウムメチル基、ホスホニウムメチル基、ホスホネートメチル基、モノハロゲン化メチル基、ホウ酸残基（−Ｂ(ＯＨ)₂）、ホルミル基、又はビニル基を表す。） The polymer of the present invention is selected from compounds represented by the following formulas (13) to (18) depending on the type of the target polymer (for example, combinations of the following formulas (13) to (15), It can be produced by reacting a combination of formulas (16) to (18).

(In the formula, A ring, B ring, G ring and H ring, R ^{1 to} R ⁴ , R ^{15 to} R ¹⁸ , m and n are the same as above. W ¹ and W ² are each independently Halogen atom, alkyl sulfonate group, aryl sulfonate group, aryl alkyl sulfonate group, borate ester residue, sulfonium methyl group, phosphonium methyl group, phosphonate methyl group, monohalogenated methyl group, boric acid residue (-B (OH) ₂ ) represents a formyl group or a vinyl group.)

From the viewpoint of the synthesis of the compounds represented by the formulas (13) to (18) and the ease of reaction, W ¹ and W ² are each independently a halogen atom, an alkyl sulfonate group, or an aryl sulfonate group. An arylalkyl sulfonate group, a boric acid ester residue, or a boric acid residue.

Examples of the boric acid ester residue include a group represented by the following formula.

Examples of the reaction method used for the synthesis of the polymer of the present invention include a method using a Suzuki coupling reaction, a method using a Grignard reaction, a method using a Stille reaction, a method using a Ni (0) catalyst, and oxidation of FeCl ₃ or the like. Examples include a method using an agent, a method using an electrochemical oxidation reaction, and a method by decomposing an intermediate compound having an appropriate leaving group. Among these, a method using a Suzuki coupling reaction, a method using a Grignard reaction, a method using a Stille reaction, and a method of polymerizing with a Ni (0) catalyst are preferable in terms of easy structure control, and in particular, Suzuki coupling. A method using a reaction, a method using a Grignard reaction, and a method using a Stille reaction are preferable from the viewpoint of easy availability of raw materials and easy reaction operation.

  In the reaction, an alkali or a suitable catalyst can be added to promote the reaction. These alkalis and appropriate catalysts may be selected according to the type of reaction, but those that are sufficiently soluble in the solvent used in the reaction are preferred.

  When the polymer of the present invention is used as a material for an organic thin film device, its purity affects the device characteristics. Therefore, after the monomer before the reaction is purified by a method such as distillation, sublimation purification or recrystallization, polymerization (reaction) is performed. It is preferable to carry out a purification treatment such as reprecipitation purification and fractionation by chromatography after the synthesis.

  Examples of the solvent used in the reaction include saturated hydrocarbons such as pentane, hexane, heptane, octane, and cyclohexane, unsaturated hydrocarbons such as benzene, toluene, ethylbenzene, and xylene, carbon tetrachloride, chloroform, dichloromethane, chlorobutane, Halogenated saturated hydrocarbons such as bromobutane, chloropentane, bromopentane, chlorohexane, bromohexane, chlorocyclohexane, bromocyclohexane, halogenated unsaturated hydrocarbons such as chlorobenzene, dichlorobenzene, trichlorobenzene, methanol, ethanol, propanol, isopropanol , Alcohols such as butanol and t-butyl alcohol, carboxylic acids such as formic acid, acetic acid and propionic acid, dimethyl ether, diethyl ether, methyl-t-butyl Ether, tetrahydrofuran, tetrahydropyran, dioxane and the like, hydrochloric, hydrobromic, hydrofluoric, sulfuric, and the like inorganic acids such as nitric acid is. These solvents may be used alone or in combination of two or more.

  After the reaction, for example, it can be obtained by usual post-treatment such as quenching with water, extraction with an organic solvent, and evaporation of the solvent. The product can be isolated and purified by chromatographic fractionation, recrystallization, and the like.

<Composition>
The composition of the present invention contains the polymer of the present invention. In addition, the composition of the present invention may contain an electron donating compound, an electron accepting compound, a polymer other than the polymer of the present invention, a solvent, an additive, and the like. In the composition of the present invention, the ratio of the polymer of the present invention in the total solid content is usually 10 to 90% by weight.

<Organic photoelectric conversion element>
The organic photoelectric conversion device of the present invention has a pair of electrodes, at least one of which is transparent or translucent, and a layer provided between the electrodes and having a heterojunction in which an electron accepting compound and an electron donating compound are adjacent to each other. If it does, it is not particularly limited, specifically,
1. A pair of electrodes, at least one of which is transparent or translucent, a first organic layer containing an electron-accepting compound provided between the electrodes, and an electron donating property provided adjacent to the first organic layer An organic photoelectric conversion element having a second organic layer containing a compound, wherein the electron-donating compound is the polymer;
2. An organic photoelectric conversion element comprising at least one organic layer containing a pair of electrodes, at least one of which is transparent or translucent, and an electron-accepting compound and an electron-donating compound provided between the electrodes, The compound is the polymer,
Either of these is preferable.

  Next, the operation mechanism of the organic photoelectric conversion element will be described. Light energy incident from a transparent or translucent electrode is absorbed by the electron-accepting compound and / or the electron-donating compound to generate excitons in which electrons and holes are combined. When the generated excitons move and reach the heterojunction interface where the electron-accepting compound and the electron-donating compound are adjacent, the HOMO (highest occupied orbit) and LUMO (lowest empty orbit) energy at the interface Due to the difference, electrons and holes are separated, and electric charges (electrons and holes) that can move independently are generated. The generated charges can be taken out as electric energy (current) by moving to the electrodes.

  For the high photoelectric conversion efficiency of the organic photoelectric conversion element, it is an electron-accepting compound and / or an electron-donating compound having an absorption region that can efficiently absorb the spectrum of desired incident light, and excitation. It is important to include a large number of heterojunction interfaces in order to efficiently separate the children and to have a charge transporting property for quickly transporting the generated charges to the electrode.

  From such a viewpoint, the organic photoelectric conversion element of the present invention includes the above 1. Or 2. From the viewpoint of including many heterojunction interfaces, 2. Is more preferable. In the organic photoelectric conversion element of the present invention, an additional layer may be provided between at least one electrode and the organic layer in the element. Examples of the additional layer include a charge transport layer that transports holes or electrons, and a buffer layer that separates the electrode from the organic layer.

  Specifically, the organic photoelectric conversion element (1.) having the buffer layer between the first organic layer containing the electron-accepting compound and one of the electrodes, the electron-accepting compound, and the electron The organic photoelectric conversion element (2.) having a buffer layer between the organic layer containing the donating compound and one of the electrodes is preferable.

  Furthermore, in the organic photoelectric conversion element of the present invention, from the viewpoint of improvement in photoelectric conversion efficiency and durability, a portion other than between a pair of transparent or semi-transparent electrodes, for example, the back surface of the substrate (that is, the substrate) An anti-reflective layer that prevents reflection of incident light on the surface on which the electrode is not formed, on the inside of the substrate, between the substrate and the electrode, on the upper electrode (that is, on the electrode formed on the organic layer), etc. An ultraviolet absorbing layer that absorbs ultraviolet rays, a protective layer for isolating from the atmosphere, and the like may be provided. These layers may be provided singly or in combination of two or more. Moreover, it is preferable to provide an antireflection layer and an ultraviolet absorption layer on the light incident surface.

  As the ultraviolet absorbing layer, a resin containing an ultraviolet absorber (details will be described later), ultrafine titanium oxide (particle diameter is usually 0.01 μm to 0.06 μm), ultrafine zinc oxide (particle diameter is usually 0.01). and a layer containing an inorganic ultraviolet absorber such as [mu] m to 0.04 [mu] m).

  The organic photoelectric conversion element of the present invention is usually formed on a substrate. This substrate may be any substrate that does not change when an electrode is formed and an organic layer is formed. Examples of the material for the substrate include glass, plastic, polymer film, and silicon. In the case of an opaque substrate, the opposite electrode (that is, the electrode far from the substrate) is preferably transparent or translucent.

  Examples of the transparent or translucent electrode material include a conductive metal oxide film and a translucent metal thin film. Specifically, indium oxide, zinc oxide, tin oxide, and a composite film made of conductive glass made of indium / tin / oxide (ITO), indium / zinc / oxide, etc. (NESA) Etc.), gold, platinum, silver, copper and the like are used, and ITO, indium / zinc / oxide, 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, a plating method, and the like. Moreover, you may use organic transparent conductive films, such as polyaniline and its derivative (s), polythiophene, and its derivative (s) as an electrode material. Furthermore, as the electrode material, a metal, a conductive polymer, or the like can be used. Preferably, one of the pair of electrodes is preferably a material having a small work function. For example, 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.

  As materials used for the charge transport layer as the additional layer, that is, the hole transport layer and the electron transport layer, an electron donating compound and an electron accepting compound described later can be used, respectively. As a material used as a buffer layer as an additional layer, an alkali metal such as lithium fluoride, a halide of an alkaline earth metal, an oxide, or the like can be used. In addition, fine particles of an inorganic semiconductor such as titanium oxide can be used.

As the buffer layer, a material that also serves as a charge transport layer is preferable. A material that transports one charge (for example, electrons) but hardly transports the other charge (for example, holes) can also be used. . As such a material, for example, arylamine derivatives such as CBP (4,4-di (N- carbazole) biphenyl), phenanthrene derivatives such as bathocuproin, etc. fullerene derivatives such as C ₆₀ are preferably used, phenanthrene derivatives, fullerene Derivatives are more preferred, phenanthrene derivatives are more preferred, and bathocuproine is particularly preferred.

<Organic thin film>
As said organic layer (organic layer containing the polymer of this invention) in the organic photoelectric conversion element of this invention, the organic thin film containing the polymer of this invention can be used, for example.

  The organic thin film has a thickness of usually 1 nm to 100 μm, preferably 2 nm to 1000 nm, more preferably 5 nm to 500 nm, and further preferably 20 nm to 200 nm.

  The said organic thin film may contain the polymer of this invention individually by 1 type, or may contain it in combination of 2 or more types. In addition, in order to enhance the hole transport property of the organic thin film, a low molecular compound and / or a polymer other than the polymer of the present invention is mixed as an electron donating compound and / or an electron accepting compound in the organic thin film. It can also be used.

  As the electron donating compound, known compounds can be used, for example, pyrazoline derivatives, arylamine derivatives, stilbene derivatives, triphenyldiamine derivatives, oligothiophene and derivatives thereof, polyvinylcarbazole and derivatives thereof, polysilane and derivatives thereof, side Examples thereof include polysiloxane derivatives having an aromatic amine in the chain or main chain, polyaniline and derivatives thereof, polythiophene and derivatives thereof, polypyrrole and derivatives thereof, polyphenylene vinylene and derivatives thereof, polythienylene vinylene and derivatives thereof, and the like.

As the electron-accepting compound, known compounds can be used, for example, oxadiazole derivatives, anthraquinodimethane and its derivatives, benzoquinone and its derivatives, naphthoquinone and its derivatives, anthraquinone and its derivatives, tetracyanoanthraquinodi. methane and its derivatives, fluorenone derivatives, diphenyldicyanoethylene and derivatives thereof, diphenoquinone derivatives, 8-hydroxyquinoline and metal complexes of derivatives thereof, polyquinoline and derivatives thereof, polyquinoxaline and its derivatives, polyfluorene and its derivatives, such as C ₆₀ Fullerenes and derivatives thereof, phenanthrene derivatives such as bathocuproine, and the like. Easily separated from excitons (electron-hole pairs) to charges at the heterojunction surface with the polymer of the present invention. In terms of sex, fullerene (e.g., C _60, etc.) is preferably a compound selected from the group consisting of and fullerene derivative, and more preferably a fullerene derivative. As the fullerene derivative, one that dissolves 10 parts by weight or more with respect to 90 parts by weight of dichlorobenzene (that is, halogen organic solvent) (for example, PCBM (Phenyl C61-butyric acid methyle ester), PCBIB (Phenyl C61-butyric acid) i-butyle ester) etc., or xylene (that is, hydrocarbon organic solvent) 90 parts by weight or more dissolves (for example, PCBNB (Phenyl C61-butyric acid n-butyle ester) etc.) Particularly preferred.

  In the organic photoelectric conversion element of the present invention, it is preferable to use an organic thin film containing the polymer of the present invention as the electron donating compound, and the organic thin film may contain the electron accepting compound.

  The organic thin film may contain materials necessary for developing various functions. For example, a sensitizer for sensitizing the function of generating charges by absorbed light, an antioxidant for preventing oxidation, a light stabilizer for increasing stability, and absorbing ultraviolet light (UV light). For example, an ultraviolet absorber. By using the polymer of the present invention in combination with the antioxidant and / or the ultraviolet absorber, the ultraviolet resistance of the resulting mixture (composition) is improved. Therefore, when this mixture (composition) is applied to an organic photoelectric conversion device, the ultraviolet resistance of the device is excellent.

  Examples of the antioxidant include hindered phenol compounds and phosphite compounds, and these may be used alone or in combination of two or more.

  Examples of the light stabilizer include benzophenone, benzotriazole, cyanoacrylate, oxalic acid, hindered amine, salicylic ester, hydroxybenzoate, benzoate, carbamate, and the like. May be used singly or in combination of two or more.

  Examples of the UV absorber include salicylic acid ester-based, benzophenone-based, benzotriazole-based, hydroxybenzoate-based, benzoate-based, cyanoacrylate-based, and carbamate-based compounds. Two or more species may be used in combination. These antioxidants, light stabilizers and ultraviolet absorbers may be used in combination of two or more, but are each 5 parts by weight or less, particularly 0.1 to 3 parts by weight with respect to 100 parts by weight of the polymer of the present invention. It is effective to mix in proportions of parts.

  The organic thin film may contain a polymer compound other than the polymer of the present invention as a polymer binder in order to enhance mechanical properties. As the polymer binder, those not extremely disturbing the electron transport property or hole transport property are preferable, and those having no strong absorption against visible light are preferably used.

  Examples of the polymer binder include poly (N-vinylcarbazole), polyaniline and derivatives thereof, polythiophene and derivatives thereof, poly (p-phenylene vinylene) and derivatives thereof, poly (2,5-thienylene vinylene) and derivatives thereof, Examples include polycarbonate, polyacrylate, polymethyl acrylate, polymethyl methacrylate, polystyrene, polyvinyl chloride, and polysiloxane.

  The method for producing the organic thin film is not particularly limited, and examples thereof include a method by film formation from a solution containing the polymer of the present invention, but the thin film may be formed by a vacuum deposition method.

  The solvent used for film formation from a solution is not particularly limited as long as it dissolves the polymer of the present invention. Examples of the solvent include unsaturated hydrocarbon solvents such as toluene, xylene, mesitylene, tetralin, decalin, bicyclohexyl, n-butylbenzene, sec-butylbezen, tert-butylbenzene, carbon tetrachloride, chloroform, dichloromethane, Halogenated saturated hydrocarbon solvents such as dichloroethane, chlorobutane, bromobutane, chloropentane, bromopentane, chlorohexane, bromohexane, chlorocyclohexane and bromocyclohexane, and halogenated unsaturated hydrocarbon solvents such as chlorobenzene, dichlorobenzene and trichlorobenzene And ether solvents such as tetrahydrofuran and tetrahydropyran. The polymer of the present invention can usually be dissolved in the solvent in an amount of 0.1% by weight or more.

  For film formation from solution, spin coating method, casting method, micro gravure coating method, gravure coating method, bar coating method, roll coating method, wire bar coating method, dip coating method, spray coating method, nozzle coating method, cap Coating methods, screen printing methods, flexographic printing methods, offset printing methods, inkjet printing methods, dispenser printing methods, and other coating methods can be used. Spin coating methods, nozzle coating methods, cap coating methods, flexographic printing methods, inkjet printing methods And the dispenser printing method are preferable.

  The organic thin film may include a step of orienting the polymer of the present invention during the production process. In the organic thin film in which the polymer of the present invention is oriented by this process, the main chain molecules or the side chain molecules are arranged in one direction, so that the electron mobility or hole mobility is improved.

  As a method for aligning the polymer of the present invention, a known method can be used as a liquid crystal alignment method. Among them, a rubbing method, a photo-alignment method, a sharing method (shear stress application method), a pulling coating method and the like are simple, useful and easy to use as an alignment method, and the rubbing method and the sharing method are preferable.

  Since the organic thin film has an electron transporting property or a hole transporting property, by controlling the transport of electrons or holes injected from the electrode or charges generated by light absorption, an organic electroluminescence device, an organic transistor, an organic solar device, and the like. It can be used for various organic thin film elements such as batteries and optical sensors. When this organic thin film is used for these organic thin film elements, it is preferable to use the organic thin film by orienting it because the electron transport property or hole transport property can be further improved.

  FIG. 1 is a schematic diagram of an organic photoelectric conversion element according to the first embodiment. In FIG. 1, an organic photoelectric conversion element 100 includes a substrate 1, a first electrode 7 a formed on the substrate 1, and an electron donating compound formed on the first electrode 7 a on the opposite side of the substrate 1. The organic layer 2 containing the polymer of the present invention and the electron-accepting compound, and a second electrode formed on the organic layer 2 on the side opposite to the first electrode 7a so as to cover a part of the organic layer 2 7b.

  FIG. 2 is a schematic diagram of an organic photoelectric conversion element according to the second embodiment. In FIG. 2, the organic photoelectric conversion element 110 includes a substrate 1, a first electrode 7 a formed on the substrate 1, and an electron donating compound formed on the first electrode 7 a on the opposite side of the substrate 1. An organic layer 3 containing the polymer of the present invention, an organic layer 4 containing an electron-accepting compound formed on the organic layer 3 on the opposite side of the first electrode 7a, and an organic layer on the opposite side of the organic layer 3 And a second electrode 7 b formed on the layer 4 so as to cover a part of the organic layer 4.

  FIG. 3 is a schematic diagram of an organic photoelectric conversion element according to the third embodiment. In FIG. 3, the organic photoelectric conversion element 120 includes a substrate 1, a first electrode 7 a formed on the substrate 1, and an electron-accepting compound formed on the first electrode 7 a on the side opposite to the substrate 1. An organic layer 4 containing, an organic layer 3 containing the polymer of the present invention as an electron donating compound formed on the organic layer 4 on the opposite side of the first electrode 7a, and an organic layer on the opposite side of the organic layer 4 A second electrode 7b formed on the layer 3 so as to cover a part of the organic layer 3 is provided.

  In the organic photoelectric conversion elements according to the first to third embodiments, a transparent or translucent electrode is used as one of the first electrode 7a and the second electrode 7b. The electrode material is as described above, and is, for example, a metal such as aluminum, gold, silver, copper, alkali metal, or alkaline earth metal. In order to obtain a high open circuit voltage, it is preferable to select each electrode so that the difference in work function is large. The material of the substrate 1 is as described above, and is silicon, glass, plastic, metal foil or the like. Other components are as described above.

  The organic photoelectric conversion elements according to the first to third embodiments emit light between the first electrode 7a and the second electrode 7b by irradiating light such as sunlight from a transparent or translucent electrode. Electric power is generated and can be operated as an organic thin film solar cell. It can also be used as an organic thin film solar cell module by integrating a plurality of organic thin film solar cells.

  The organic photoelectric conversion elements according to the first to third embodiments irradiate light from a transparent or translucent electrode in a state where a voltage is applied between the first electrode 7a and the second electrode 7b. As a result, a photocurrent flows and it can be operated as an organic photosensor. It can also be used as an organic image sensor by integrating a plurality of organic photosensors.

<Application of device>
An organic thin film solar cell module and an organic image sensor can be configured by integrating a plurality of the organic photoelectric conversion elements of the present invention. That is, the organic thin film solar cell module and the organic thin film solar cell module of the present invention are formed by integrating a plurality of the organic photoelectric conversion elements of the present invention.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely using an Example and a comparative example, they do not limit this invention at all.

(Number average molecular weight)
In the following examples, the number average molecular weight of the polymer was determined by gel permeation chromatography (GPC, manufactured by Shimadzu Corporation, trade name: LC-10Avp) in terms of polystyrene. The polymer to be measured was dissolved in tetrahydrofuran to a concentration of about 0.5% by weight, and 50 μL was injected into GPC. Tetrahydrofuran was used as the GPC mobile phase, and flowed at a flow rate of 0.6 mL / min. As for the column, two TSKgel SuperHM-H (manufactured by Tosoh) and one TSKgel SuperH2000 (manufactured by Tosoh) were connected in series. A differential refractive index detector (manufactured by Shimadzu Corporation, trade name: RID-10A) was used as the detector.

（式中、ｔは重合度を表す。）
で表されるペンタチエニル−フルオレンコポリマー（以下、「重合体Ａ」という） １２．２１ｇを合成した。重合体Ａのポリスチレン換算の数平均分子量は４．５×１０⁴であった。 <Example 1>
9,9-dihexylfluorene-2,7-diboronic acid ester (8.012 g, 0.017 mol) and 5,5 ″ ″-3 ″, 4 ″ -dihexyl-α-pentathiophene (13. 16 g, 0.018 mol) according to the method described in WO2005 / 092947 pamphlet:

(In the formula, t represents the degree of polymerization.)
12.21 g of a pentathienyl-fluorene copolymer represented by the following (hereinafter referred to as “polymer A”) was synthesized. The number average molecular weight in terms of polystyrene of the polymer A was 4.5 × 10 ⁴ .

（式中、ｔは重合度を表す。）
で表されるペンタチエニル−フルオレンコポリマー（以下、「重合体Ｂ」という） １ｇを合成した。重合体Ｂのポリスチレン換算の数平均分子量は６．１×１０⁴であった。 <Comparative Example 1>
9,9-Dioctylfluorene-2,7-diboronic acid ester (1.06 g, 2.25 mmol) and 5,5 ″ ″-3 ″, 4 ″ -dihexyl-α-pentathiophene (1. 48 g, 2.02 mmol) according to the method described in WO 2005/092947 pamphlet:

(In the formula, t represents the degree of polymerization.)
1 g of a pentathienyl-fluorene copolymer (hereinafter referred to as “polymer B”) represented by the formula: The number average molecular weight in terms of polystyrene of the polymer B was 6.1 × 10 ⁴ .

で表される割合でこれらの繰り返し単位を有する重合体Ｃ ２．０３ｇを合成した。重合体Ｃのポリスチレン換算の数平均分子量は３．２×１０⁴であった。 <Example 2>
9,9-dihexylfluorene-2,7-diboronic acid ester (0.986 g, 2.079 mmol), 9,9-dioctylfluorene-2,7-diboronic acid ester (0.276 g, 0.520 mmol), Using 5,5 ''''-3'', 4 ''-dihexyl-α-pentathiophene (2.024 g, 2.707 mmol) according to the method described in WO 2005/092947 pamphlet, Following formula:

2.03 g of polymer C having these repeating units at a ratio represented by the following was synthesized. The number average molecular weight in terms of polystyrene of the polymer C was 3.2 × 10 ⁴ .

<Example 3>
-Preparation of organic photoelectric conversion element Weigh 0.050g of PCBM (Phenyl C61-butyric acid methyl ester, manufactured by Frontier Carbon Co., Ltd., trade name: E100), add dichlorobenzene to 0.5 g, and add 10% by weight. A solution was prepared. When this solution is heated to 100 ° C. with stirring, PCBM is completely dissolved, and no precipitation is observed even when the solution is returned to room temperature. PCBM is not less than 10% by weight in dichlorobenzene (ie, PCBM and dichlorobenzene). It was confirmed that PCBM was dissolved in a mixed solution of

Next, 0.030 g of polymer A was weighed, and dichlorobenzene was added to make 2 g to prepare a 1.5 wt% solution. By heating the solution to 100 ° C. with stirring, the polymer A was completely dissolved. When the solution was returned to room temperature and attempted to be filtered with a membrane filter, it could be filtered with a 0.2 μm filter, and it was confirmed that the solubility was good. Separately, a 1.5 wt% dichlorobenzene solution of PCBM was prepared, and each solution was mixed at a ratio of polymer A: PCBM = 1: 1 (weight basis) to obtain a coating solution. A glass substrate with ITO ultrasonically cleaned with acetone was subjected to ozone UV treatment to perform surface cleaning. Using the coating solution, a mixed film of polymer A and PCBM was formed with a thickness of 60 nm by spin coating to obtain a uniform and flat organic film. On top of this, an aluminum electrode was deposited to a thickness of 70 nm by a vacuum deposition method, and an organic photoelectric conversion element A having an effective area of 2 × 2 mm ² was produced.

・ Evaluation of organic thin-film solar cell characteristics Using organic photoelectric conversion element A, solar simulator simulated sunlight (passing air volume (AM1.5), irradiance (100 mW / cm ² )) is measured and solar cell characteristics are measured. did. The characteristics of an open-circuit voltage of 0.58 V, a short-circuit current of 2.6 mA / cm ² , and a photoelectric conversion efficiency of 0.57% were obtained.

・ Evaluation of optical sensor characteristics Using the organic photoelectric conversion element A, the current-voltage characteristics in the dark were measured without exposure to light. When a voltage of -1V was applied to ITO, -3.2 × 10 ^-5 mA / A dark current of cm ² flowed. Next, 4 mW / cm ² of white light was irradiated, current-voltage characteristics at the time of light irradiation were measured, and when a voltage of −1 V was applied to ITO, a photocurrent of −0.36 mA / cm ² flowed. The ratio of photocurrent to dark current was 1.1 × 10 ⁴ .

<Comparative example 2>
-Preparation of an organic photoelectric conversion element It carried out similarly to Example 3, the polymer B was melt | dissolved completely by preparing the 1.5 weight% dichlorobenzene solution of the polymer B, heating to 100 degreeC, stirring a solution. When this solution was returned to room temperature and filtration was attempted with a membrane filter, it could not be filtered even with a 1 μm filter, and the solubility was poor. Without filtering, a solution prepared by mixing a polymer B and PCBM 1.5 wt% dichlorobenzene solution in 1: 1 (weight basis) was prepared, and a mixed film of the polymer B and PCBM was formed to a thickness of about 80 nm by spin coating. Although it was formed with a thickness, a uniform and flat organic film could not be obtained and was inhomogeneous. On top of that, an aluminum electrode was deposited to a thickness of 70 nm by a vacuum deposition method, and an organic photoelectric conversion element B having an effective area of 2 × 2 mm ² was produced.

-Evaluation of organic thin-film solar cell characteristic Using the organic photoelectric conversion element B, it carried out similarly to Example 3, and measured the solar cell characteristic. The characteristics of an open-circuit voltage of 0.58 V, a short-circuit current of 0.87 mA / cm ² and a photoelectric conversion efficiency of 0.24% were obtained.

<Example 4>
-Preparation of an organic photoelectric conversion element It carried out similarly to Example 3, 1.5 weight% dichlorobenzene of the polymer C was prepared, and the polymer C melt | dissolved completely by heating a solution to 100 degreeC, stirring. When the solution was returned to room temperature and filtration was attempted with a membrane filter, it could be filtered with a 0.2 μm filter, and the solubility was good. A 1.5 wt% dichlorobenzene solution of polymer C and PCBM was mixed 1: 1 (weight basis) to prepare a coating solution. A mixed film of the polymer C and PCBM was formed with a thickness of 85 nm by a spin coating method to obtain a uniform and flat organic film. On top of this, an aluminum electrode was vapor-deposited with a thickness of 70 nm to produce an organic photoelectric conversion element C having an effective area of 2 × 2 mm ² .

-Evaluation of organic thin film solar cell characteristic The solar cell characteristic was measured like Example 3 using the organic photoelectric conversion element C. As shown in FIG. The characteristics of an open-circuit voltage of 0.61 V, a short-circuit current of 3.04 mA / cm ² , and a photoelectric conversion efficiency of 1.0% were obtained.

<Example 5>
-Preparation of an organic photoelectric conversion element The solution which mixed polymer A and PCBM 1: 2 (weight basis) was prepared like Example 3, and the mixed film of polymer A and PCBM by a spin coat method Was formed with a thickness of 140 nm to obtain a homogeneous organic film. On top of that, BCP (Bathocuproine: 2,9-Dimethyl-4,7-diphenyl-1,10-phenanthroline, manufactured by Aldrich) is deposited with a thickness of 50 nm by vacuum deposition, and then an aluminum electrode is deposited with a thickness of 70 nm. The organic photoelectric conversion element D having an effective area of 2 × 2 mm ² was produced.

-Evaluation of organic thin-film solar cell characteristic Using the organic photoelectric conversion element D, it carried out similarly to Example 3, and measured the solar cell characteristic. The characteristics of an open-circuit voltage of 0.83 V, a short-circuit current of 4.0 mA / cm ² , and a photoelectric conversion efficiency of 2.3% were obtained.

<Example 6>
-Preparation of organic photoelectric conversion element In the same manner as in Example 3, 1.5 wt% dichlorobenzene of the polymer C was prepared, and the solution was heated to 100 ° C while stirring to completely dissolve the polymer C. When the solution was returned to room temperature and filtration was attempted with a membrane filter, it could be filtered with a 0.2 μm filter, and the solubility was good. A coating solution was prepared by mixing Polymer C and PCBM in dichlorobenzene (1.5 wt%) in a weight ratio of 1: 2. A mixed film of polymer C and PCBM was formed with a thickness of 85 nm by a spin coating method to obtain a uniform and flat organic film. On top of that, BCP was deposited in a thickness of 50 nm by a vacuum deposition method, and then an aluminum electrode was deposited in a thickness of 70 nm to produce an organic photoelectric conversion element E having an effective area of 2 × 2 mm ² .

-Evaluation of organic thin-film solar cell characteristic Using the organic photoelectric conversion element E, it carried out similarly to Example 3, and measured the solar cell characteristic. The characteristics of an open-circuit voltage of 0.78 V, a short-circuit current of 3.47 mA / cm ² , and a photoelectric conversion efficiency of 1.3% were obtained.

<Example 7>
-Preparation of organic photoelectric conversion device 0.050 g PCBNB (Phenyl C61-butyric acid n-butyl ester, manufactured by Frontier Carbon Co., Ltd., trade name: E200) was weighed, and xylene was added to make 0.5 g, 10% by weight A solution of was prepared. When the solution is heated to 100 ° C. with stirring, PCBNB is completely dissolved, and no precipitation is observed even when the solution is returned to room temperature. PCBNB is not less than 10% by weight in xylene (ie, a mixed solution of PCBNB and xylene). It was confirmed that PCBNB was dissolved by 10 wt% or more.
In the same manner as in Example 3, a 1.5 wt% xylene solution of polymer A was prepared, and the polymer was completely dissolved by heating the solution to 100 ° C. with stirring. When the solution was returned to room temperature and filtration was attempted with a membrane filter, it could be filtered with a 0.2 μm filter, and the solubility was good. A 1.5 wt% xylene solution of Polymer A and PCBNB was mixed 1: 1 (weight basis) to prepare a coating solution. A mixed film of polymer A and PCBNB was formed with a thickness of 70 nm by spin coating to obtain a uniform and flat organic film. On top of that, an aluminum electrode was vapor-deposited with a thickness of 70 nm by vacuum vapor deposition to produce an organic photoelectric conversion element G having an effective area of 2 × 2 mm ² .
-Evaluation of organic thin film solar cell characteristics Using the organic photoelectric conversion element G, the solar cell characteristics were measured in the same manner as in Example 3. The characteristics of an open-circuit voltage of 0.64 V, a short-circuit current of 2.20 mA / cm ² and a photoelectric conversion efficiency of 0.56% were obtained.

<Evaluation>
Table 1 summarizes the properties of the polymers synthesized in the examples and comparative examples and the organic photoelectric conversion elements prepared. As can be seen from the examples, the polymer of the present invention is excellent in solubility in an organic solvent and has a high charge transporting property. The charge can be efficiently transported to the electrode, and the obtained organic photoelectric conversion element showed high photoelectric conversion efficiency. Moreover, the photoelectric conversion efficiency improved more by providing a buffer layer between the organic layer containing the polymer of this invention, and an electrode. Furthermore, in a preferred embodiment, by combining with a fullerene derivative having high solubility in xylene, the polymer of the present invention is dissolved in an organic solvent other than a halogen-based solvent having a high environmental load, and a photoelectric conversion element having a uniform film quality is obtained. I was able to make it. And it has confirmed that this element showed high photoelectric conversion efficiency.

＊表中、溶解性の欄において、○、×の記号は、
「○」：「メンブランフィルターでろ過が可能であった」
「×」：「メンブランフィルターでろ過が不可能であった」
を意味する。また、「ＤＣＢ」はジクロロベンゼンを意味する。

* In the table, in the solubility column,
“○”: “It was possible to filter with a membrane filter”
“×”: “It was impossible to filter with a membrane filter”
Means. “DCB” means dichlorobenzene.

It is a schematic diagram of the organic photoelectric conversion element which concerns on 1st Embodiment. It is a schematic diagram of the organic photoelectric conversion element which concerns on 2nd Embodiment. It is a schematic diagram of the organic photoelectric conversion element which concerns on 3rd Embodiment.

Explanation of symbols

1 Substrate 2 Organic film (organic layer) containing electron donating compound and electron accepting compound
3 Organic film containing an electron-donating compound (organic layer)
4 Organic film (organic layer) containing electron-accepting compound
7a First electrode 7b Second electrode 100 Organic photoelectric conversion device 110 according to the first embodiment Organic photoelectric conversion device 120 according to the second embodiment Organic photoelectric conversion device according to the third embodiment

Claims (20)

A repeating unit comprising one or more structures represented by the following formula (1), one structure represented by the following formula (2) and one or more structures represented by the following formula (3) ( A polymer containing a repeating unit A), the maximum carbon number of the carbon main chain contained in the alkyl group represented by R ¹ or R ² and the carbon contained in the alkyl group represented by R ³ or R ⁴ A polymer characterized in that the difference from the maximum carbon number of the main chain is 0 or 1.

(In the formula, A ring and B ring each independently represent a benzene ring which may have a substituent, and have a bond on the benzene ring. R ¹ , R ² , R ³ and R ⁴ Each independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or an aryl group having 6 to 60 carbon atoms. A part or all of the hydrogen atoms may be substituted with fluorine atoms, and the aryl group may have a substituent, provided that at least one of R ¹ and R ² is the alkyl group. , R ³ and R ⁴ are the alkyl group.) ^2. The polymer according to claim ¹ , wherein R ¹ , R ² , R ³ and R ⁴ are linear or branched alkyl groups having 5 to 20 carbon atoms.   The polymer according to claim 1 or 2, wherein two or three structures represented by the formula (3) are continuous.   The structure represented by the formula (2) and the structure represented by the formula (3) include a repeating unit having a structure in which a total of 4 or more are connected. The polymer according to item. The structure represented by the formula (2) and the structure represented by the formula (3) are combined to form a structure represented by the following formula (9). 5. The polymer according to 4.

(In the formula, R ³ and R ⁴ are as defined above, and m and n each independently represent an integer of 1 to ^3. However, the sum of m and n is an integer of 3 to 6. ) Further, one structure represented by the following formula (10), one structure represented by the following formula (11), and one or two or more structures represented by the above formula (3) are repeated. 6. The polymer according to claim 1, comprising a unit (repeating unit B), wherein a ratio of the repeating unit A to all repeating units exceeds 50 mol%.

(In the formula, each of the E ring and the F ring independently represents a benzene ring which may have a substituent or a naphthalene ring which may have a substituent, and may have the substituent. R ¹¹ , R ¹² , R ¹³ and R ¹⁴ each independently represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, which has a bond on a good benzene ring or an optionally substituted naphthalene ring. Represents an alkoxy group having 1 to 20 carbon atoms or an aryl group having 6 to 60 carbon atoms, in which some or all of the hydrogen atoms may be substituted with fluorine atoms. It may have a substituent, provided that at least one of R ¹³ and R ¹⁴ is not a hydrogen atom, the E ring and the F ring are benzene rings, and at least one of R ¹¹ and R ¹² is alkyl. a group, at least one of alkyl of R ¹³ and R ¹⁴ If it is, the maximum number of carbon atoms in the carbon backbone constituting the alkyl group represented by R ¹¹ or R ^12, the maximum number of carbon atoms in the carbon backbone constituting the alkyl group represented by R ¹³ or R ¹⁴ The difference is 2 or more.) The number average molecular weight in terms of polystyrene is 10 ³ to 10 ⁸ , The polymer according to claim 1.   The composition containing the polymer as described in any one of Claims 1-7.   A pair of electrodes, at least one of which is transparent or translucent, a first organic layer containing an electron-accepting compound provided between the electrodes, and an electron donating property provided adjacent to the first organic layer An organic photoelectric conversion element having a second organic layer containing a compound, wherein the electron donating compound is the polymer according to any one of claims 1 to 7. Conversion element.   The organic photoelectric conversion device according to claim 9, further comprising a buffer layer between the first organic layer containing the electron-accepting compound and one of the electrodes.   An organic photoelectric conversion device comprising at least one organic layer containing a pair of electrodes, at least one of which is transparent or translucent, and an electron-accepting compound and an electron-donating compound provided between the electrodes. An organic photoelectric conversion element, wherein the compound is the polymer according to any one of claims 1 to 7.   The organic photoelectric conversion element according to claim 11, further comprising a buffer layer between the organic layer containing the electron-accepting compound and the electron-donating compound and one of the electrodes.   The organic photoelectric conversion element according to claim 10 or 12, wherein the buffer layer contains bathocuproine.   The organic photoelectric conversion device according to any one of claims 9 to 13, wherein the electron-accepting compound is a compound selected from the group consisting of fullerenes and fullerene derivatives.   The organic photoelectric conversion device according to claim 14, wherein the fullerene derivative is dissolved in 10 parts by weight or more with respect to 90 parts by weight of dichlorobenzene.   The organic photoelectric conversion device according to claim 14, wherein the fullerene derivative is dissolved in 10 parts by weight or more with respect to 90 parts by weight of xylene.   The organic thin film containing the polymer as described in any one of Claims 1-7.   Furthermore, the organic thin film of Claim 17 containing antioxidant and / or a ultraviolet absorber.   The organic thin-film solar cell module formed by integrating the organic photoelectric conversion element as described in any one of Claims 9-16.   The organic image sensor formed by integrating the organic photoelectric conversion element as described in any one of Claims 9-16.

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