JP2010010438A - Organic photoelectric conversion element and composition useful for its manufacture - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic photoelectric conversion element whose photoelectric conversion efficiency is high. <P>SOLUTION: This organic photoelectric conversion element includes a pair of electrodes and a functional layer between those electrodes, wherein the functional layer includes a polymer including repeated units expressed with a formula (1a) and/or repeated units expressed with a formula (1b) and repeated units expressed with a formula (2). In the formulas (1a) and (1b), R shows an alkyl group, an alkoxy group or an aryl group which may have a displacement group. The several pieces of R may be identical or different. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

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

  In recent years, attention has been paid to organic photoelectric conversion elements (organic solar cells, optical sensors, etc.) using light energy, and organic photoelectric conversion elements containing various polymers have been studied in order to improve various characteristics of the elements. Yes. Specifically, an organic photoelectric conversion element including a layer having a polymer containing a fluorenediyl group and a thiophenediyl group as a repeating unit has been proposed (Non-Patent Document 1).

Applied Physics Letters Vol.84, No.10 1653-1655 (2004)

  However, the organic photoelectric conversion element has a problem that the photoelectric conversion efficiency is low.

  Then, an object of this invention is to provide an organic photoelectric conversion element with high photoelectric conversion efficiency.

（式（１ａ）及び（１ｂ）中、Ｒは、アルキル基、アルコキシ基又は置換基を有していてもよいアリール基を表す。複数個あるＲは、同一でも相異なっていてもよい。）

（式中、Ｒ¹、Ｒ²、Ｒ³、Ｒ⁴、Ｒ⁵及びＲ⁶は、同一又は相異なり、水素原子、アルキル基、アルコキシ基又は置換基を有していてもよいアリール基を表す。ｘは１又は２を表し、ｙは０又は１を表し、ｚは０、１又は２を表す。Ｒ¹、Ｒ²、Ｒ³及びＲ⁴が、各々、複数個存在する場合は、それらは、同一であっても相異なっていてもよい。該アルキル基、該アルコキシ基及び該アリール基は、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。） That is, the present invention first has a pair of electrodes and a functional layer between the electrodes, and the functional layer is a repeating unit represented by the formula (1a) and / or a repeating unit represented by the formula (1b). Provided is an organic photoelectric conversion element having a polymer containing a unit and a repeating unit represented by the formula (2).

(In formulas (1a) and (1b), R represents an alkyl group, an alkoxy group or an aryl group which may have a substituent. A plurality of R may be the same or different.)

Wherein R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are the same or different and represent a hydrogen atom, an alkyl group, an alkoxy group or an aryl group which may have a substituent. X represents 1 or 2, y represents 0 or 1, z represents 0, 1 or 2. When a plurality of R ¹ , R ² , R ³ and R ⁴ are present, May be the same or different. In the alkyl group, alkoxy group and aryl group, some or all of the hydrogen atoms may be substituted with fluorine atoms.)

  The present invention secondly provides the organic photoelectric conversion device in which an organic layer is provided adjacent to the functional layer, and the organic layer has an electron donating compound or an electron accepting compound.

  Thirdly, the present invention provides the organic photoelectric conversion device, wherein the functional layer further contains an electron accepting compound or an electron donating compound.

  Fourthly, the present invention provides the organic photoelectric conversion device, wherein the functional layer further contains a fullerene derivative.

（式（１ａ）及び（１ｂ）中、Ｒは、アルキル基、アルコキシ基又は置換基を有していてもよいアリール基を表す。複数個あるＲは、同一でも相異なっていてもよい。）

（式中、Ｒ¹、Ｒ²、Ｒ³、Ｒ⁴、Ｒ⁵及びＲ⁶は、同一又は相異なり、水素原子、アルキル基、アルコキシ基又は置換基を有していてもよいアリール基を表す。ｘは１又は２を表し、ｙは０又は１を表し、ｚは０、１又は２を表す。Ｒ¹、Ｒ²、Ｒ³及びＲ⁴が、各々、複数個存在する場合は、それらは、同一であっても相異なっていてもよい。該アルキル基、該アルコキシ基及び該アリール基は、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。） Fifthly, the present invention provides a multilayer comprising a fullerene derivative, a repeating unit represented by the formula (1a) and / or a repeating unit represented by the formula (1b), and a repeating unit represented by the formula (2). A composition containing the coalescence is provided.

(In formulas (1a) and (1b), R represents an alkyl group, an alkoxy group or an aryl group which may have a substituent. A plurality of R may be the same or different.)

Wherein R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are the same or different and represent a hydrogen atom, an alkyl group, an alkoxy group or an aryl group which may have a substituent. X represents 1 or 2, y represents 0 or 1, z represents 0, 1 or 2. When a plurality of R ¹ , R ² , R ³ and R ⁴ are present, May be the same or different. In the alkyl group, alkoxy group and aryl group, some or all of the hydrogen atoms may be substituted with fluorine atoms.)

  Since the organic photoelectric conversion element of the present invention exhibits high photoelectric conversion efficiency, it is extremely useful industrially.

  Hereinafter, the present invention will be described in detail.

<Polymer>
The polymer used in the organic photoelectric conversion device of the present invention comprises a repeating unit represented by the formula (1a) and / or a repeating unit represented by the formula (1b) and a repeating unit represented by the formula (2). Including.

-Structure represented by Formula (1a) / Formula (1b) In Formula (1a) and Formula (1b), R represents the aryl group which may have an alkyl group, an alkoxy group, or a substituent.

  When R is an alkyl group or an alkoxy group, from the viewpoint of solubility of the polymer in the solvent, the number of carbon atoms is preferably 1-20, more preferably 2-18, and 3-12. More preferably it is.

  The alkyl group represented by R preferably has 1 to 20 carbon atoms. Examples of the alkyl group include a methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, n-hexyl group, n -An octyl group, an isooctyl group, n-decyl group, n-dodecyl group, n-pentadecyl group, n-octadecyl group etc. are mentioned. In the alkyl group, some or all of the hydrogen atoms may be substituted with fluorine atoms.

  The alkoxy group represented by R preferably has 1 to 20 carbon atoms. Examples of the alkoxy group include methoxy group, ethoxy group, propyloxy group, i-propyloxy group, butoxy group, i-butoxy group, t-butoxy group, pentyloxy group, hexyloxy group, cyclohexyloxy group, and heptyloxy. Group, octyloxy group, 2-ethylhexyloxy group, nonyloxy group, decyloxy group, 3,7-dimethyloctyloxy group and the like. In the alkoxy group, some or all of the hydrogen atoms may be substituted with fluorine atoms.

  The aryl group which may have a substituent represented by R preferably has 6 to 60 carbon atoms, and more preferably 6 to 30 carbon atoms. Examples of the aryl group include a phenyl group, a 1-naphthyl group, and a 2-naphthyl group. Examples of the substituent that the aryl group has include a halogen atom, an alkyl group, and an alkoxy group.

  Examples of the repeating unit represented by the formula (1a) include the following repeating units.

  Examples of the repeating unit represented by the formula (1b) include the following repeating units.

  The polymer used for this invention may contain 1 type of repeating units represented by Formula (1a), or may contain 2 or more types. Moreover, 1 type of repeating units represented by Formula (1b) may be included, or 2 or more types may be included.

Structure represented by the formula (2) In the formula (2), specific examples of the alkyl group represented by R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are represented by the aforementioned R. And the same groups as the alkyl group to be prepared.

In the formula (2), specific examples of the alkoxy group represented by R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ include the same groups as the alkoxy group represented by R described above. It is done.

In the formula (2), the aryl group which may have a substituent represented by R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ represents the substituent represented by R described above. The same group as the aryl group which may have is mentioned.

  Examples of the repeating unit represented by the formula (2) include the following repeating units.

  The polymer used for this invention may contain 1 type of repeating units represented by Formula (2), or may contain 2 or more types.

-Polymer used in the present invention The polymer used in the present invention is represented by one repeating unit selected from the specific examples of the repeating unit represented by the above formula (1a) and / or the above formula (1b). It is preferable that one repeating unit selected from the specific example of the repeating unit to be selected and one repeating unit selected from the specific example of the repeating unit represented by the above formula (2) are adjacent in the polymer. It is more preferable to have a repeating unit represented by (3a) or formula (3b).

（式中、Ｒ、Ｒ¹、Ｒ²、Ｒ³及びＲ⁴は、前記と同じ意味を表す。）

(In the formula, R, R ¹ , R ² , R ³ and R ⁴ represent the same meaning as described above.)

（式中、ｍは繰り返し単位数を表す。） Specific examples of the polymer used in the present invention include the following polymers.

(In the formula, m represents the number of repeating units.)

  In Formula (1a), Formula (1b), Formula (3a), and Formula (3b), R is preferably an alkyl group.

  The polymer used in the present invention has a repeating unit represented by the formula (1a) and / or a repeating unit represented by the formula (1b) and a repeating unit represented by the formula (2). When the functional layer containing the polymer and the electron-accepting compound used in the present invention is formed with improved solubility in a solvent, a functional layer having a good phase separation structure is obtained, and the photoelectric conversion efficiency is improved. It is thought that it is raised.

  In the polymer used in the present invention, the total of the repeating unit represented by the formula (1), the repeating unit represented by the formula (2) and the repeating unit represented by the formula (3) 20-100 mol% is preferable with respect to the sum total of all the repeating units, and from a viewpoint of obtaining high photoelectric conversion efficiency, More preferably, it is 50-100 mol%.

The weight average molecular weight in terms of polystyrene of the polymer used in the present invention is preferably 10 ³ to 10 ⁸ , more preferably 10 ³ to 10 ⁷ , and still more preferably 10 ³ to 10 ⁶ .

  When the polymer used in the present invention is used for the production of an organic photoelectric conversion element, if the polymerization active group remains as a terminal group, characteristics such as durability of the resulting element may be deteriorated. It is preferred to protect with a stable group.

  Examples of the stable group for protecting the terminal include an alkyl group, an alkoxy group, a fluoroalkyl group, a fluoroalkoxy group, an aryl group, an arylamino group, and a monovalent heterocyclic group. Moreover, it replaces with stable group and the hydrogen atom may be located in the terminal. From the viewpoint of enhancing the hole transport property at the terminal group, an electron donating group such as an arylamino group is preferred. As the terminal group, those having a conjugated bond continuous with the conjugated structure of the main chain are also preferable, for example, a group bonded to an aryl group or a monovalent heterocyclic group via a carbon-carbon bond, etc. Can be mentioned. Examples of the arylamino group include a phenylamino group and a diphenylamino group. Examples of the monovalent heterocyclic group include a chenyl group, a pyrrolyl group, a furyl group, a pyridyl group, a piperidyl group, a quinolyl group, and an isoquinolyl group.

  The polymer used in the present invention is preferably a conjugated polymer compound. Here, the conjugated polymer compound means a compound in which main chains of molecules constituting the compound are substantially conjugated.

<Method for producing polymer>
The polymer used in the present invention may be produced by any method. For example, after synthesizing a monomer having a functional group suitable for the polymerization reaction to be used, it is dissolved in an organic solvent as necessary. It can synthesize | combine by superposing | polymerizing using the polymerization method by the well-known aryl coupling using an alkali, a suitable catalyst, a ligand, etc. The synthesis of the monomer can be performed with reference to methods disclosed in, for example, JP-A-2006-182920 and JP-A-2006-335933.

The polymerization method by aryl coupling is not particularly limited. For example, a monomer having a boric acid residue or a boric acid ester residue, a halogen atom such as a bromine atom, an iodine atom or a chlorine atom, or a trifluoromethanesulfonate group, p -Monomers having a sulfonate group such as toluene sulfonate group and inorganic bases such as sodium carbonate, potassium carbonate, cesium carbonate, tripotassium phosphate, potassium fluoride, tetrabutylammonium fluoride, tetrabutylammonium chloride, tetrabutyl bromide Palladium [tetrakis (triphenylphosphine)], [tris (dibenzylideneacetone)] dipalladium, palladium acetate, bis (triphenylphosphine) palladium dichloride in the presence of organic bases such as ammonium and tetraethylammonium hydroxide Palladium complexes or nickel complexes such as bis (cyclooctadiene) nickel and, if necessary, triphenylphosphine, tri (2-methylphenyl) phosphine, tri (2-methoxyphenyl) phosphine, diphenylphosphinopropane , Polymerization method by Suzuki coupling reaction using a catalyst comprising a ligand such as tri (cyclohexyl) phosphine and tri (tert-butyl) phosphine; monomers having a sulfonate group such as a halogen atom or a trifluoromethanesulfonate group Using a catalyst comprising a nickel zero-valent complex such as bis (cyclooctadiene) nickel and a ligand such as bipyridyl, or [bis (diphenylphosphino) ethane] nickel dichloride, [bis (diphenylphosphino) Propane] A catalyst comprising a nickel complex such as nickel dichloride and, if necessary, a ligand such as triphenylphosphine, diphenylphosphinopropane, tri (cyclohexyl) phosphine, tri (tert-butyl) phosphine, and zinc, magnesium A method of polymerizing by a Yamamoto coupling reaction using a reducing agent such as a compound under dehydrating conditions as necessary; a compound having a magnesium halide group and a compound having a halogen atom [bis (diphenylphosphino) ethane] Polymerization is carried out by Kumada-Tamao coupling reaction using a nickel catalyst such as nickel dichloride and [bis (diphenylphosphino) propane] nickel dichloride, which is reacted under dehydration conditions, and polymerized by aryl coupling reaction. Method, a method of polymerization with an oxidizer such as FeCl _3, a method in which electrochemical oxidation polymerization.

  In the polymerization method using aryl coupling, a solvent is usually used. This solvent may be selected in consideration of the polymerization reaction used, the solubility of the monomer and polymer, and the like. Specifically, organic solvents such as tetrahydrofuran, toluene, 1,4-dioxane, dimethoxyethane, N, N-dimethylacetamide, N, N-dimethylformamide, a mixed solvent of two or more thereof, or water and The two-phase system is exemplified. In the Suzuki coupling reaction, an organic solvent such as tetrahydrofuran, toluene, 1,4-dioxane, dimethoxyethane, N, N-dimethylacetamide, N, N-dimethylformamide, a mixed solvent of two or more thereof, or with them A two-phase system with water is preferred. In general, the reaction solvent is preferably subjected to deoxygenation treatment in order to suppress side reactions. In the Yamamoto coupling reaction, organic solvents such as tetrahydrofuran, toluene, 1,4-dioxane, dimethoxyethane, N, N-dimethylacetamide, N, N-dimethylformamide, and a mixed solvent of two or more thereof are preferable. In general, the reaction solvent is preferably subjected to deoxygenation treatment in order to suppress side reactions.

  Among the polymerization methods by aryl coupling, from the viewpoint of reactivity, Suzuki coupling reaction and Yamamoto coupling reaction are preferable, and Suzuki coupling reaction and Yamamoto coupling reaction using a nickel zero-valent complex are more preferable. More specifically, with respect to polymerization by Suzuki coupling, see, for example, Journal of Polymer Science: Part A: Polymer Chemistry, Vol. 39, 1533-1556 (2001) can be referred to. With respect to polymerization by Yamamoto coupling, for example, known methods described in Macromolecules 1992, 25, 1214-1223 can be referred to.

  In the polymerization method by aryl coupling, the reaction temperature is not particularly limited as long as the reaction solution can be kept in a liquid state, but the lower limit is preferably −100 ° C. from the viewpoint of reactivity. The upper limit is preferably −20 ° C., particularly preferably 0 ° C., and the upper limit is preferably 200 ° C., more preferably 150 ° C., and particularly preferably 120 ° C. from the viewpoint of stability.

  In the polymerization reaction by aryl coupling, the polymer of the present invention can be removed from the reaction system after completion of the reaction according to a known method. For example, the polymer of the present invention can be obtained by adding a reaction solution to a lower alcohol such as methanol and precipitating the resulting precipitate by filtration and drying. When the purity of the obtained polymer is low, it can be purified by ordinary methods such as recrystallization, continuous extraction with a Soxhlet extractor, column chromatography and the like.

<Organic photoelectric conversion element>
The organic photoelectric conversion element of the present invention has a pair of electrodes and a functional layer between the electrodes, and the functional layer is a repeating unit represented by the formula (1a) and / or a repeating unit represented by the formula (1b). A polymer containing a unit and a repeating unit represented by the formula (2), specifically,
1. An organic photoelectric conversion device comprising a pair of electrodes, a functional layer provided between the electrodes and containing the polymer, and an organic layer provided adjacent to the functional layer and containing an electron donating compound;
2. An organic photoelectric conversion element having a pair of electrodes, an organic layer containing an electron-accepting compound provided between the electrodes, and a functional layer provided adjacent to the organic layer and containing the polymer;
3. An organic photoelectric conversion element having at least one functional layer containing a pair of electrodes and an electron-accepting compound and an electron-donating compound provided between the electrodes, wherein the electron-donating compound or the electron-accepting compound is An organic photoelectric conversion element which is a polymer;
4). An organic photoelectric conversion device having at least one functional layer containing a pair of electrodes and an electron-accepting compound and an electron-donating compound provided between the electrodes, wherein the electron-donating compound is the polymer, An organic photoelectric conversion element in which the electron-accepting compound is a fullerene derivative;
Etc. In general, at least one of the pair of electrodes is transparent or translucent. Hereinafter, this case will be described as an example.

  In addition, the 3. 4. In the organic photoelectric conversion element, the ratio of the electron accepting compound in the functional layer containing the electron accepting compound and the electron donating compound is 10 to 1000 parts by weight with respect to 100 parts by weight of the electron donating compound. It is preferably 50 to 500 parts by weight.

  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 to each other, electrons and holes are separated due to the difference in HOMO energy and LUMO energy at the interface. Electric charges (electrons and holes) that can move are generated. The generated charges can be taken out as electric energy (current) by moving to the electrodes.

  In order for the organic photoelectric conversion element to have high photoelectric conversion efficiency, the electron-accepting compound and the electron-donating compound have an absorption region that can efficiently absorb a desired incident light spectrum, In order for the heterojunction interface to efficiently separate excitons, it is important that the heterojunction interface includes a large number of heterojunction interfaces and that the heterojunction interface has a charge transporting property for quickly transporting charges generated by the heterojunction interface to the electrode.

  From such a point of view, the organic photoelectric conversion element of the present invention has the above described 3. Or 4. From the viewpoint of including many heterojunction interfaces, the above 4. Is more preferable. In the organic photoelectric conversion device of the present invention, an additional layer may be provided between at least one electrode and a functional layer or an organic layer in the device. Examples of the additional layer include a charge transport layer that transports holes or electrons.

  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 thereof (NESA) manufactured using a conductive material made of indium / tin / oxide (ITO), indium / zinc / oxide, or the like. 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.

<Organic thin film>
As said functional layer (functional layer containing the polymer of this invention) in the organic photoelectric conversion element of this invention, the organic thin film containing the said polymer 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 order to enhance the hole transport property of the organic thin film, a low molecular compound and / or a polymer other than the polymer is mixed and used as the electron donating compound and / or the electron accepting compound in the organic thin film. You can also.

  Examples of the electron-donating compound include, in addition to the polymer used in the present invention, for example, pyrazoline derivatives, arylamine derivatives, stilbene derivatives, triphenyldiamine derivatives, oligothiophene and derivatives thereof, polyvinylcarbazole and derivatives thereof, polysilane and derivatives thereof. Derivatives, polysiloxane derivatives having an aromatic amine in the side 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.

Examples of the electron-accepting compound include, in addition to the polymer used in the present invention, for example, oxadiazole derivatives, anthraquinodimethane and its derivatives, benzoquinone and its derivatives, naphthoquinone and its derivatives, anthraquinone and its derivatives, tetracyano Anthraquinodimethane and derivatives thereof, fluorenone derivatives, diphenyldicyanoethylene and derivatives thereof, diphenoquinone derivatives, metal complexes of 8-hydroxyquinoline and derivatives thereof, polyquinoline and derivatives thereof, polyquinoxaline and derivatives thereof, polyfluorene and derivatives thereof, C fullerenes and derivatives thereof ₆₀ such as 2,9-dimethyl-4,7-diphenyl-1,10-phenanthrene derivatives phenanthroline and the like, especially the preferred fullerenes and derivatives thereof .

  The electron-donating compound and the electron-accepting compound are relatively determined from the energy levels of these compounds.

Examples of fullerenes include C ₆₀ , C ₇₀ , carbon nanotubes, and derivatives thereof. Specific examples of the structure of the C ₆₀ derivative include the following structures.

<Composition>
The composition of the present invention contains a fullerene derivative and the polymer. In the composition, the ratio of the fullerene derivative is preferably 10 to 1000 parts by weight, and more preferably 50 to 500 parts by weight with respect to 100 parts by weight of the polymer. The composition of this invention can be used for the functional layer of an organic photoelectric conversion element.

<Method for producing organic thin film>
The organic thin film may be produced by any method. For example, the organic thin film may be produced by a film formation method from a solution containing the polymer or composition used in the present invention, or a thin film is formed by a vacuum deposition method. May be.

  The solvent used for film formation from a solution is not particularly limited as long as it dissolves the polymer or composition used in the present invention. Examples of the solvent include unsaturated hydrocarbon solvents such as toluene, xylene, mesitylene, tetralin, decalin, bicyclohexyl, n-butylbenzene, sec-butylbenzene, tert-butylbenzene, carbon tetrachloride, chloroform, dichloromethane, Halogenated saturated hydrocarbon solvents such as dichloroethane, chlorobutane, bromobutane, chloropentane, bromopentane, chlorohexane, bromohexane, chlorocyclohexane and bromocyclohexane, halogenated unsaturated hydrocarbon solvents such as chlorobenzene, dichlorobenzene and trichlorobenzene, tetrahydrofuran And ether solvents such as tetrahydropyran. The polymer or composition used in 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, screen printing method, flexographic method Coating methods such as a printing method, an offset printing method, an ink jet printing method, a dispenser printing method, a nozzle coating method, a capillary coating method can be used, and a spin coating method, a flexographic printing method, an ink jet printing method, and a dispenser printing method are preferable.

  By irradiating light such as sunlight from a transparent or translucent electrode, the organic photoelectric conversion element generates a photovoltaic force between the electrodes 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.

  In addition, by applying light from a transparent or translucent electrode in a state where a voltage is applied between the electrodes, 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.

  Examples will be shown below for illustrating the present invention in more detail, but the present invention is not limited to these examples.

The number average molecular weight in terms of polystyrene was determined by size exclusion chromatography (SEC).
Column: TOSOH TSKgel SuperHM-H (2) + TSKgel SuperH2000 (4.6 mm Id x 15 cm); Detector: RI (SHIMADZU RID-10A); Mobile phase: Tetrahydrofuran (THF)

化合物Ａ

5L-3口フラスコを窒素置換し、ブロモ−３−ｎ−ヘキシルベンゼン２２６ｇを量り取り、２．５Ｌの脱水ＴＨＦに溶解させた。この溶液を−７５℃以下に冷却し、２．５Ｍ ｎ−ブチルリチウム／ヘキサン溶液３５８ｍｌを滴下し、−７５℃以下に保ちながら５時間攪拌した。この溶液に、２−メトキシカルボニル−４，４‘−ジブロモビフェニル１５０ｇを４００ｍｌの脱水ＴＨＦに溶解させた溶液を−７０℃以下に保ちながら滴下した。この溶液を室温までゆっくりと昇温後、終夜攪拌した。反応溶液を０℃で攪拌しながら、１５０ｍｌの水を滴下した。溶媒を留去した後、残渣に水２００ｍｌを加え、１Ｌのヘキサンを用いて１回抽出し、１００ｍｌのヘキサンを用いて２回抽出した。抽出した有機層を合わせ、飽和食塩水２００ｍｌで洗浄し、水層を１００ｍｌのヘキサンで再抽出した後、硫酸マグネシウムを用いて乾燥した。溶媒を留去したところ、２６４ｇの化合物Ａの粗生成物を得た。粗生成物である化合物Ａの精製はおこなわず、次の工程に用いた。 <Synthesis of Compound A>

Compound A

The 5L-3 neck flask was purged with nitrogen, and 226 g of bromo-3-n-hexylbenzene was weighed and dissolved in 2.5 L of dehydrated THF. This solution was cooled to −75 ° C. or lower, and 358 ml of 2.5M n-butyllithium / hexane solution was added dropwise, and stirred for 5 hours while maintaining the temperature at −75 ° C. or lower. A solution prepared by dissolving 150 g of 2-methoxycarbonyl-4,4′-dibromobiphenyl in 400 ml of dehydrated THF was added dropwise to this solution while keeping at −70 ° C. or lower. The solution was slowly warmed to room temperature and stirred overnight. While the reaction solution was stirred at 0 ° C., 150 ml of water was added dropwise. After the solvent was distilled off, 200 ml of water was added to the residue, extracted once with 1 L of hexane, and extracted twice with 100 ml of hexane. The extracted organic layers were combined, washed with 200 ml of saturated brine, the aqueous layer was re-extracted with 100 ml of hexane, and then dried using magnesium sulfate. When the solvent was distilled off, 264 g of a crude product of Compound A was obtained. The crude product, compound A, was not purified and used in the next step.

化合物Ｂ

３Ｌ３口フラスコに上記で合成した化合物Ａを２６４ｇ取り、９００ｍｌのジクロロメタンに溶解させ、窒素置換した。この溶液を０℃以下に冷却し、５℃以下に保ちながら３フッ化ホウ素ジエチルエーテル錯体２４５ｍｌを滴下した。室温までゆっくり昇温後、終夜攪拌した。この反応溶液を２Ｌの氷水中に攪拌しながら注ぎ、３０分攪拌した。分液し、水層を１００ｍｌのジクロロメタンで抽出した。その後、有機層を合わせ、１０％リン酸カリウム水溶液１Ｌ加えて分液し、有機層を１Ｌの水で２回洗浄した。硫酸マグネシウムを用いて乾燥後、溶媒を留去して得られたオイルを２００ｍｌのトルエンに溶解させ、シリカゲルを敷いたグラスフィルターを通し、ろ過した。溶媒を留去した後、５００ｍｌのメタノールを加えて激しく攪拌した。得られた結晶をろ過し、メタノールで洗浄した。ヘキサン／酢酸ブチル混合溶媒系で再結晶をおこない、化合物Ｂを１２１ｇ得た。

¹H-NMR（400MHz、CDCl₃）
δ０．８６（6H，ｔ）、１．２６（12H，ｍ）、１．５２（４Ｈ，ｍ）、２．５１（４Ｈ，ｔ）、６．８７（２Ｈ，ｄ）、７．００（２Ｈ，ｓ）、７．０４（２Ｈ，ｄ）、７．１２（２Ｈ，ｔ）、７．４６（２Ｈ，ｄｄ）、７．４８（２Ｈ，ｄ）、７．５５（２Ｈ，ｄ）

¹³Ｃ-NMR（400MHz、CDCl₃）
δ１４．１、２２．６、２８．９、３１．４、３１．７、３５．９、６５．７、１２１．５、１２１．８、１２５．１、１２７．２、１２８．４、１２９．５、１３０．８、１３８．１、１４３．２、１４４．３、１５３．３ <Synthesis of Compound B>

Compound B

264 g of the compound A synthesized above was taken in a 3 L 3-neck flask, dissolved in 900 ml of dichloromethane, and purged with nitrogen. The solution was cooled to 0 ° C. or lower, and 245 ml of boron trifluoride diethyl ether complex was added dropwise while maintaining the temperature at 5 ° C. or lower. After slowly warming to room temperature, the mixture was stirred overnight. The reaction solution was poured into 2 L of ice water with stirring and stirred for 30 minutes. The layers were separated and the aqueous layer was extracted with 100 ml of dichloromethane. Thereafter, the organic layers were combined, 1 L of a 10% aqueous potassium phosphate solution was added to separate the layers, and the organic layer was washed twice with 1 L of water. After drying using magnesium sulfate, the oil obtained by distilling off the solvent was dissolved in 200 ml of toluene, filtered through a glass filter covered with silica gel. After the solvent was distilled off, 500 ml of methanol was added and stirred vigorously. The obtained crystals were filtered and washed with methanol. Recrystallization was performed in a hexane / butyl acetate mixed solvent system to obtain 121 g of Compound B.

¹ H-NMR (400 MHz, CDCl ₃ )
δ 0.86 (6H, t), 1.26 (12H, m), 1.52 (4H, m), 2.51 (4H, t), 6.87 (2H, d), 7.00 (2H) , S), 7.04 (2H, d), 7.12 (2H, t), 7.46 (2H, dd), 7.48 (2H, d), 7.55 (2H, d)

¹³ C-NMR (400 MHz, CDCl ₃ )
δ 14.1, 22.6, 28.9, 31.4, 31.7, 35.9, 65.7, 121.5, 121.8, 125.1, 127.2, 128.4, 129. 5, 130.8, 138.1, 143.2, 144.3, 153.3

化合物Ｃ

２Ｌ３口フラスコに化合物Ｂを５０ｇ取り、窒素置換した。脱水ＴＨＦ５００ｍｌを加え、−７０℃以下に冷却した。この溶液を−７０℃以下に保ちながら、２．５Ｍ ｎ−ブチルリチウム／ヘキサン溶液６８ｍｌを滴下した。滴下後、温度を保ちながら４時間攪拌した。２−イソプロポキシ−４，４，５，５−テトラメチル−１，３，２−ジオキサボロラン４４ｍｌを加えた後、室温までゆっくり昇温し終夜攪拌した。−３０℃に冷却し、２Ｍ塩酸／ジエチルエーテル溶液７８ｍｌを滴下した後、室温まで昇温した。溶媒を留去した後、トルエン４００ｍｌを加えて溶解し、シリカゲルを敷いたグラスフィルターを通してろ過し、得られた溶液の溶媒を留去したところ、５０ｇの粗生成物が得られた。窒素雰囲気下でトルエン／アセトニトリル溶媒から再結晶し、３４ｇの化合物Ｃを得た。

¹H-NMR（400MHz、CDCl₃）
δ０．８６（６Ｈ，ｔ）、１．２６−１．２９（１２Ｈ，ｍ）、１．３１（２４Ｈ，ｓ）、１．５２−１．５３（４Ｈ，ｍ）、２．５０（４Ｈ，ｔ）、６．９２（２Ｈ，ｄ）、７．００（２Ｈ，ｄ）、７．０８（２Ｈ，ｔ）、７．１３（２Ｈ，ｓ）、７．７７（２Ｈ，ｄ）、７．８１−７．８２（４Ｈ，ｍ）

¹³Ｃ-NMR（400MHz、CDCl₃）
δ１４．３、２２．８、２５．１、２９．２、３１．９、３６．３、８３．９、１１９．９、１２５．７、１２６．７、１２８．１、１２９．１、１３２．７、１３４．３、１４２．９、１４３．０、１４５．９、１５１．６
<Synthesis of Compound C>

Compound C

50 g of Compound B was taken into a 2 L 3-neck flask and purged with nitrogen. 500 ml of dehydrated THF was added and cooled to −70 ° C. or lower. While maintaining this solution at −70 ° C. or lower, 68 ml of 2.5M n-butyllithium / hexane solution was added dropwise. After dropping, the mixture was stirred for 4 hours while maintaining the temperature. After adding 44 ml of 2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane, the mixture was slowly warmed to room temperature and stirred overnight. After cooling to −30 ° C. and adding 78 ml of 2M hydrochloric acid / diethyl ether solution dropwise, the mixture was warmed to room temperature. After distilling off the solvent, 400 ml of toluene was added for dissolution, followed by filtration through a glass filter covered with silica gel, and the solvent of the resulting solution was distilled off to obtain 50 g of a crude product. Recrystallization from toluene / acetonitrile solvent under a nitrogen atmosphere gave 34 g of compound C.

¹ H-NMR (400 MHz, CDCl ₃ )
δ 0.86 (6H, t), 1.26-1.29 (12H, m), 1.31 (24H, s), 1.52-1.53 (4H, m), 2.50 (4H, m) t), 6.92 (2H, d), 7.00 (2H, d), 7.08 (2H, t), 7.13 (2H, s), 7.77 (2H, d), 7. 81-7.82 (4H, m)

¹³ C-NMR (400 MHz, CDCl ₃ )
δ14.3, 22.8, 25.1, 29.2, 31.9, 36.3, 83.9, 119.9, 125.7, 126.7, 128.1, 129.1, 132. 7, 134.3, 142.9, 143.0, 145.9, 151.6

（式中、ｎは繰り返し単位数を表す。）

で表される高分子化合物１、０．５８ｇを得た。高分子化合物１のポリスチレン換算の重量平均分子量は９．３×１０⁴であり、ポリスチレン換算の数平均分子量は２．７×１０⁴であった。 (Synthesis of polymer compound 1)
1.477 g of compound C, 0.648 g of 5,5′-dibromo-2,2′-bithiophene, methyltrioctylammonium chloride (trade name: aliquat336, manufactured by Aldrich, CH ₃ N [(CH ₂ ) ₇ CH ₃ ] ₃ Cl, density: 0.884 g / ml (25 ° C., (registered trademark)) 0.50 g, palladium (II) acetate 4.7 mg, and tris (2-methoxyphenyl) phosphine 23.4 mg The inside of the reaction vessel was sufficiently replaced with argon gas. To this reaction vessel, 80 ml of toluene deaerated in advance by bubbling argon gas was added. Next, 10 ml of a 16.7% by weight aqueous sodium carbonate solution deaerated by bubbling with an argon gas in advance was added dropwise to the solution, and then the temperature was raised to a temperature at which the solvent was refluxed, followed by refluxing for 10 hours. The reaction was performed in an argon gas atmosphere.
Next, after cooling the obtained reaction solution to near room temperature, a mixed solution of 0.16 g of phenylboric acid / 0.7 ml of tetrahydrofuran was added to this reaction solution, and the mixture was refluxed for 3.5 hours. The reaction was performed in an argon gas atmosphere.
After completion of the reaction, the obtained reaction solution was cooled, and then the obtained reaction solution was allowed to stand and the separated toluene layer was recovered. Next, the obtained toluene layer was poured into methanol and re-precipitated, and the generated precipitate was collected. This precipitate was dried under reduced pressure and then dissolved in chloroform. Next, the obtained chloroform solution was filtered to remove insoluble matters, and then the chloroform solution was purified by passing through an alumina column. Next, the obtained chloroform solution was concentrated under reduced pressure, poured into methanol, re-precipitated, and the generated precipitate was collected. The precipitate was washed with methanol and then dried under reduced pressure to obtain the following formula:

(In the formula, n represents the number of repeating units.)

Thus, 0.58 g of the polymer compound 1 represented by the formula (1) was obtained. The polymer compound 1 had a polystyrene equivalent weight average molecular weight of 9.3 × 10 ⁴ and a polystyrene equivalent number average molecular weight of 2.7 × 10 ⁴ .

で表される化合物18.55g(34.98mmol)、5，5'−ジブロモ−2，2'−ビチオフェン 11.72g（36.17mmol）、メチルトリオクチルアンモニウムクロライド（商品名：aliquat336、Aldrich製、CH₃N[(CH₂)₇CH₃]₃Cl、密度：0.884g/ml（25℃）、（登録商標））4.00g、ジクロロビス（トリフェニルホスフィン）パラジウム（ＩＩ）（Pd(PPh₃)₂Cl₂） 0.023g及びトルエン300mlを入れ、55℃に加熱、撹拌した。そこへ、2mol/lの炭酸ナトリウム水溶液60mlを滴下し、滴下終了後、95℃に昇温し、24時間反応させた。得られた溶液に、フェニルボロン酸2.0g、テトラヒドロフラン40ml及びPd(PPh₃)₂Cl₂ 0.023ｇを加え、更に24時間反応させた。得られた溶液を400mlのトルエンで希釈し、有機相を抽出後、温水600mlで3回洗浄した。得られた溶液に7.5重量％ジエチルジチオカルバミン酸ナトリウム三水和物水溶液300mlを加え、80℃で一晩撹拌した。静置して水相を除去後、2重量％酢酸600mlで洗浄し、続いて温水600mlで2回洗浄した。得られた溶液に500mlのトルエンを加え、3Lのメタノールに2回に分けて注加、再沈殿させた。得られた溶液をろ過して回収した重合体を1Lのメタノールで洗浄し、60℃で終夜真空乾燥した。得られた重合体を2Lの熱トルエンに溶解させ、セライト、シリカゲル及び塩基性アルミナを用いたカラムを通した。800mlの熱トルエンでカラムを洗浄し、得られた溶液を1300mlまで濃縮した。3Lのメタノールに2回に分けて注加し、重合体を再沈殿させ、得られた沈殿物をろ過して重合体を回収した。この重合体を、メタノール、アセトン、メタノール(各500ml)で順番に洗浄し、60℃で真空乾燥することにより、下記式：

（式中、ｎは繰り返し単位数を表す。）
で表される高分子化合物２を得た。高分子化合物２のポリスチレン換算の数平均分子量Ｍｎは2.2×10⁴であり、ポリスチレン換算の重量平均分子量Ｍｗは4.4×10⁴であった。 (Synthesis of polymer compound 2)
In a 1 L three-neck flask purged with nitrogen, the following formula:

18.55 g (34.98 mmol) of a compound represented by the following formula: 5,72′-dibromo-2,2′-bithiophene 11.72 g (36.17 mmol), methyltrioctylammonium chloride (trade name: aliquat336, manufactured by Aldrich, CH ₃ N [ (CH ₂ ) ₇ CH ₃ ] ₃ Cl, density: 0.884 g / ml (25 ° C.), (registered trademark) 4.00 g, dichlorobis (triphenylphosphine) palladium (II) (Pd (PPh ₃ ) ₂ Cl ₂ ) 0.023 g and 300 ml of toluene were added and heated to 55 ° C. and stirred. Thereto, 60 ml of a 2 mol / l sodium carbonate aqueous solution was added dropwise. After completion of the addition, the temperature was raised to 95 ° C. and reacted for 24 hours. To the obtained solution, 2.0 g of phenylboronic acid, 40 ml of tetrahydrofuran and 0.023 g of Pd (PPh ₃ ) ₂ Cl ₂ were added, and the mixture was further reacted for 24 hours. The obtained solution was diluted with 400 ml of toluene, the organic phase was extracted, and then washed with 600 ml of hot water three times. To the obtained solution was added 300 ml of an aqueous 7.5 wt% sodium diethyldithiocarbamate trihydrate solution, and the mixture was stirred at 80 ° C. overnight. The aqueous phase was removed by standing, and then washed with 600 ml of 2% by weight acetic acid, followed by washing twice with 600 ml of warm water. 500 ml of toluene was added to the resulting solution, and the mixture was poured into 3 L of methanol in two portions and reprecipitated. The polymer collected by filtration of the resulting solution was washed with 1 L of methanol and dried in vacuo at 60 ° C. overnight. The obtained polymer was dissolved in 2 L of hot toluene, and passed through a column using celite, silica gel and basic alumina. The column was washed with 800 ml of hot toluene and the resulting solution was concentrated to 1300 ml. The mixture was poured into 3 L of methanol in two portions to reprecipitate the polymer, and the resulting precipitate was filtered to recover the polymer. The polymer was washed in turn with methanol, acetone and methanol (500 ml each) and dried in vacuo at 60 ° C. to obtain the following formula:

(In the formula, n represents the number of repeating units.)
The high molecular compound 2 represented by these was obtained. The number average molecular weight Mn in terms of polystyrene of the polymer compound 2 was 2.2 × 10 ⁴ , and the weight average molecular weight Mw in terms of polystyrene was 4.4 × 10 ⁴ .

<Example 1>
(Production and evaluation of organic thin-film solar cells)
The weight ratio of fullerene derivative (C60PCBM (Phenyl C61-butyric acid methyl ester, manufactured by Frontier Carbon Co., Ltd., trade name: E100)), which is an electron-accepting compound, and polymer compound 1, which is an electron-donating compound, in a 3: 1 ratio And dissolved in o-dichlorobenzene to a concentration of 2% by weight. The obtained solution was filtered through a Teflon (registered trademark) filter having a pore size of 1.0 μm to prepare a coating solution.

A glass substrate provided with an ITO film with a thickness of 150 nm by a sputtering method was subjected to surface treatment by ozone UV treatment. Next, the coating solution was applied by spin coating to obtain a functional layer (film thickness: 80 nm) of the organic thin film solar cell. Then, lithium fluoride was vapor-deposited with a film thickness of 4 nm with a vacuum vapor deposition machine, and then aluminum was vapor-deposited with a film thickness of 100 nm to produce an organic thin film solar cell. The degree of vacuum at the time of vapor deposition was 1 to 9 × 10 ⁻³ Pa in all cases. The shape of the organic thin film solar cell thus obtained was a regular square of 2 mm × 2 mm. The obtained organic thin-film solar cell is irradiated with a certain amount of light using a solar simulator (trade name: OTENTO-SUN II: AM1.5G filter, irradiance: 100 mW / cm ² ). The photoelectric conversion efficiency was obtained by measurement. The obtained results are shown in Table 1.

<Comparative Example 1>
An organic thin film solar cell was produced and evaluated in the same manner as in Example 1 except that the polymer compound 1 in Example 1 was replaced with the polymer compound 2. The obtained results are shown in Table 1.

Claims (8)

A pair of electrodes, a functional layer between the electrodes, the functional layer represented by formula (1a) and / or a repeating unit represented by formula (1b), and a formula (2) The organic photoelectric conversion element which has a polymer containing the repeating unit.

(In formulas (1a) and (1b), R represents an alkyl group, an alkoxy group or an aryl group which may have a substituent. A plurality of R may be the same or different.)

Wherein R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are the same or different and represent a hydrogen atom, an alkyl group, an alkoxy group or an aryl group which may have a substituent. X represents 1 or 2, y represents 0 or 1, z represents 0, 1 or 2. When a plurality of R ¹ , R ² , R ³ and R ⁴ are present, May be the same or different. In the alkyl group, alkoxy group and aryl group, some or all of the hydrogen atoms may be substituted with fluorine atoms.) The organic photoelectric conversion element of Claim 1 in which a polymer contains the repeating unit represented by the repeating unit represented by Formula (3a) or Formula (3b).

(In the formula, R, R ¹ , R ² , R ³ and R ⁴ represent the same meaning as described above.)   The organic photoelectric conversion element according to claim 1, wherein R is an alkyl group.   The organic photoelectric conversion element according to claim 1, wherein an organic layer is provided adjacent to the functional layer, and the organic layer has an electron donating compound or an electron accepting compound.   The organic photoelectric conversion element according to claim 1, wherein the functional layer further contains an electron accepting compound or an electron donating compound.   The organic photoelectric conversion element according to claim 1, wherein the functional layer further contains a fullerene derivative.   The organic photoelectric conversion element according to claim 6, wherein the ratio of the fullerene derivative in the functional layer is 10 to 1000 parts by weight with respect to 100 parts by weight of the polymer. A composition comprising a fullerene derivative, a repeating unit represented by formula (1a) and / or a repeating unit represented by formula (1b), and a polymer comprising a repeating unit represented by formula (2). .

(In formulas (1a) and (1b), R represents an alkyl group, an alkoxy group or an aryl group which may have a substituent. A plurality of R may be the same or different.)

Wherein R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are the same or different and represent a hydrogen atom, an alkyl group, an alkoxy group or an aryl group which may have a substituent. X represents 1 or 2, y represents 0 or 1, z represents 0, 1 or 2. When a plurality of R ¹ , R ² , R ³ and R ⁴ are present, May be the same or different. In the alkyl group, alkoxy group and aryl group, some or all of the hydrogen atoms may be substituted with fluorine atoms.)