JP2013070000A - Organic photoelectric conversion element and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic photoelectric conversion element which exhibits an excellent photoelectric conversion efficiency, and a method of manufacturing the same.SOLUTION: The organic photoelectric conversion element has a layer containing a high-molecular compound including a repeating unit expressed by the formula (1). In the formula (1), R1 and R2 are each independently a group selected from the group consisting of substituent groups consisting of hydrogen, and C, H and/or X (X is a heteroatom), and Ar1 and Ar2 are each independently a group selected from the group consisting of a divalent aromatic ring consisting of C and H, and a divalent aromatic ring consisting of C, H and X (X is a heteroatom).

Description

  The present invention relates to an organic photoelectric conversion element and a method for producing the same.

  In recent years, studies using an organic semiconductor material for an active layer of an organic photoelectric conversion element (such as an organic solar cell or an optical sensor) have been actively conducted. In particular, an organic thin film solar cell, which is a solar cell composed of an organic semiconductor thin film, can be manufactured at a low cost by a simple manufacturing method as compared with conventional silicon and compound semiconductor solar cells. It is expected as a solar cell.

As such an organic thin film solar cell, a Schottky type, a pn heterojunction type, a bulk heterojunction type, a pin junction type, and the like have been proposed. In particular, a p-type organic semiconductor (for example, a polythiophene derivative or a polyphenylene vinylene derivative) and an n-type organic semiconductor (for example, a fullerene (C ₆₀ ) derivative) are blended, and the pn junction surface is dispersed on the whole thin film in nano-order. Such a bulk heterojunction type has high conversion efficiency, and many studies have been started as a promising technology.

  An organic thin film solar cell has a configuration in which a thin film of an organic compound is sandwiched between a cathode and an anode, and a method for forming a thin film is roughly classified into a vapor deposition method and a coating method. The vapor deposition method is a method of forming a thin film on a substrate in a vacuum mainly using a low molecular compound. On the other hand, the coating method is a method of forming a thin film on a substrate using a solution, such as ink jet or printing, and the use efficiency of the material is high, and it is suitable for a large area, and manufactures a low-cost organic thin film solar cell. This is an indispensable technique.

  As a specific organic thin film solar cell, for example, one having an organic layer containing poly3-hexylthiophene which is a conjugated polymer compound and C60PCBM which is a fullerene derivative is known (for example, see Non-Patent Document 1). . Various conjugated polymers have been developed for organic thin-film solar cell applications (for example, see Non-Patent Document 2).

F. Padinger, R. S. Rittberger, and N. S. Sariciftci, "Effects of postproduction treatment on plastic solar cells", Advanced Functional Materials, vol. 13, no. 1, pp. 85-88, 2003 Y. J. Cheng, S. H. Yang and C. S. Hsu, "Synthesis of conjugated polymers for organic solar cell applications", Chem. Rev., 2009, 109, 5868-5923

  An object of this invention is to provide the organic photoelectric conversion element which shows the outstanding photoelectric conversion efficiency, and its manufacturing method.

（但し、式（１）中、Ｒ１及びＲ２は、それぞれ独立に、水素、並びに、Ｃ、Ｈ及び／又はＸ（Ｘはヘテロ原子である）からなる置換基からなる群より選択される基であり、
Ａｒ１及びＡｒ２は、それぞれ独立に、Ｃ及びＨからなる二価の芳香環、並びに、Ｃ、Ｈ及びＸ（Ｘはヘテロ原子である）からなる二価の芳香環からなる群から選択される基である。）
本発明の実施形態として、例えば、Ｒ１が水素原子である有機光電変換素子、Ｒ１が水素原子であり、Ｒ２が結合する水素原子数が２以下の炭素原子である有機光電変換素子、Ｒ１が水素原子であり、Ｒ２が結合する水素原子数が１以下の炭素原子である有機光電変換素子、が挙げられる。
また、本発明の実施形態は、前記高分子化合物が、さらに式（２）〜（２７）で表される単位を１種以上含む有機光電変換素子に関する。

さらに、本発明の実施形態として、前記高分子化合物の数平均分子量が、１，０００〜５００，０００である有機光電変換素子、また、前記高分子化合物の数平均分子量が２，５００〜１００，０００である有機光電変換素子が挙げられる。
また、本発明の実施形態の有機光電変換素子において、前記高分子化合物を電子供与性有機材料とすることが可能である。また、本発明の実施形態の有機光電変換素子において、前記高分子化合物を含む層を有機光電変換層とすることが可能である。
さらに、本発明の実施形態は、上記有機光電変換素子を製造する方法であって、前記高分子化合物を含有する溶液を塗布することにより前記高分子化合物を含む層を形成する工程を有する、有機光電変換素子の製造方法に関する。 Embodiments of the present invention relate to an organic photoelectric conversion element having a layer containing a polymer compound containing a repeating unit represented by the following formula (1).

(In the formula (1), R1 and R2 are each independently a group selected from the group consisting of hydrogen and a substituent consisting of C, H and / or X (X is a heteroatom)). Yes,
Ar1 and Ar2 are each independently a group selected from the group consisting of a divalent aromatic ring consisting of C and H, and a divalent aromatic ring consisting of C, H and X (X is a heteroatom). It is. )
As an embodiment of the present invention, for example, an organic photoelectric conversion element in which R1 is a hydrogen atom, an organic photoelectric conversion element in which R1 is a hydrogen atom and the number of hydrogen atoms to which R2 is bonded is 2 or less, and R1 is hydrogen An organic photoelectric conversion element which is an atom and a carbon atom having 1 or less hydrogen atoms to which R2 is bonded is exemplified.
Moreover, embodiment of this invention is related with the organic photoelectric conversion element in which the said high molecular compound further contains 1 or more types of units represented by Formula (2)-(27).

Furthermore, as embodiment of this invention, the number average molecular weight of the said high molecular compound is 1,000-500,000, Moreover, the number average molecular weight of the said high molecular compound is 2,500-100, 000 organic photoelectric conversion elements.
In the organic photoelectric conversion device of the embodiment of the present invention, the polymer compound can be an electron donating organic material. In the organic photoelectric conversion element of the embodiment of the present invention, the layer containing the polymer compound can be an organic photoelectric conversion layer.
Furthermore, an embodiment of the present invention is a method for producing the above organic photoelectric conversion element, which includes a step of forming a layer containing the polymer compound by applying a solution containing the polymer compound. The present invention relates to a method for manufacturing a photoelectric conversion element.

  The organic photoelectric conversion element of the present invention exhibits excellent photoelectric conversion efficiency. Moreover, the manufacturing method of the organic photoelectric conversion element of this invention is a method which can manufacture the organic photoelectric conversion element which shows the outstanding photoelectric conversion efficiency simply at low cost.

It is sectional drawing which shows an example of an organic photoelectric conversion element.

（但し、式（１）中、Ｒ１及びＲ２は、それぞれ独立に、水素、並びに、Ｃ、Ｈ及び／又はＸ（Ｘはヘテロ原子である）からなる置換基からなる群より選択される基であり、
Ａｒ１及びＡｒ２は、それぞれ独立に、Ｃ及びＨからなる二価の芳香環、並びに、Ｃ、Ｈ及びＸ（Ｘはヘテロ原子である）からなる二価の芳香環からなる群から選択される基である。） [Organic photoelectric conversion element]
The organic photoelectric conversion element of embodiment of this invention has a layer containing the high molecular compound containing the repeating unit represented by following formula (1).

(In the formula (1), R1 and R2 are each independently a group selected from the group consisting of hydrogen and a substituent consisting of C, H and / or X (X is a heteroatom)). Yes,
Ar1 and Ar2 are each independently a group selected from the group consisting of a divalent aromatic ring consisting of C and H, and a divalent aromatic ring consisting of C, H and X (X is a heteroatom). It is. )

[Polymer compound]
The high molecular compound contained in an organic photoelectric conversion element contains the repeating unit represented by the said Formula (1).
In formula (1), R 1 and R 2 are each independently selected from hydrogen and a substituent consisting of C, H and / or X. Examples of the substituent consisting of C, H and / or X include an aliphatic substituent consisting of C and H, an aromatic substituent consisting of C and H, an aromatic substituent consisting of C, H and X, and other Cs. , H and / or X substituents (including aliphatic substituents). X is a heteroatom, and examples of X include O (oxygen atom), N (nitrogen atom), S (sulfur atom), Si (silicon atom), and halogen atom. C is a carbon atom and H is a hydrogen atom. In formula (1), preferably, R1 and R2 do not simultaneously become hydrogen.

  Examples of the aliphatic substituent composed of C and H include linear or branched alkyl groups having 1 to 12 carbon atoms, cycloalkyl groups having 1 to 12 carbon atoms, alkenyl groups having 1 to 12 carbon atoms, and carbon numbers. Examples thereof include 1 to 12 alkynyl groups.

  As the aromatic substituent composed of C and H, an aryl group optionally having a linear or branched alkyl group having 1 to 12 carbon atoms or a cycloalkyl group having 1 to 12 carbon atoms as a substituent. Groups, arylalkyl groups, arylalkenyl groups, arylalkynyl groups, bicyclic aryl groups such as biphenyl groups, and condensed ring aryl groups such as naphthyl groups and anthracenyl groups.

  The aromatic substituent composed of C, H and X may be a linear or branched alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms. May be an aryloxy group, arylthio group, arylalkoxy group, arylalkylthio group, thienyl group, pyrrolyl group, furyl group, pyridyl group, piperidyl group, quinolyl group, isoquinolyl group and the like.

Specifically, the substituent consisting of C, H and / or X (including the aliphatic substituent) includes a substituent consisting of C, H and X, a substituent consisting of C and X, and H and X. Substituents, substituents consisting of X, and the like can be mentioned.
Substituents consisting of C, H and / or X include alkoxy groups, alkylthio groups, hydroxy groups, hydroxyalkyl groups, amino groups, substituted amino groups, silyl groups, substituted silyl groups, silyloxy groups, substituted silyloxy groups, halogen atoms , An acyl group, an acyloxy group, an imino group, an amide group, an imide group, a carboxyl group, a substituted carboxyl group, a cyano group, and an alkyl group having these substituents.

  Ar1 and Ar2 are each independently a group selected from the group consisting of a divalent aromatic ring consisting of C and H, and a divalent aromatic ring consisting of C, H and X (X is a heteroatom). It is. Examples of X include O (oxygen atom), N (nitrogen atom), S (sulfur atom), Si (silicon atom), halogen atom, and the like.

  Examples of the divalent aromatic ring composed of C and H include an aromatic hydrocarbon ring such as a divalent monocyclic ring or a condensed ring formed by condensing 2 or more, preferably 2 to 5 rings. . Specifically, divalent benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, pyrene ring, perylene ring, tetracene ring, pentacene ring, fluorene ring, indenofluorene ring, azulene ring, heptalene ring, biphenylene ring, Indacene ring, acenaphthylene ring, phenalene ring, fluoranthene ring, acephenanthrylene ring, aceantolylene ring, triphenylene ring, chrysene ring, naphthacene ring, picene ring, pentaphen ring, tetraphenylene ring, hexaphen ring, hexacene ring, rubicene ring , Aromatic hydrocarbon rings such as coronene ring, trinaphthylene ring, heptaphene ring and heptacene ring.

  The divalent aromatic ring composed of C, H and X (where X is a heteroatom) is a divalent heteromonocycle or a condensation formed by condensation of 2 or more, preferably 2 to 5 rings. And heteroaromatic rings such as rings. Specifically, bivalent pyridine ring, pyrimidine ring, pyridazine ring, pyrazine ring, quinoline ring, isoquinoline ring, quinoxaline ring, quinazoline ring, acridine ring, phenanthroline ring, thiophene ring, benzothiophene ring, dibenzothiophene ring, Thiophene oxide ring, benzothiophene oxide ring, dibenzothiophene oxide ring, thiophene dioxide ring, benzothiophene dioxide ring, dibenzothiophene dioxide ring, furan ring, benzofuran ring, dibenzofuran ring, pyrrole ring, indole ring, dibenzopyrrole ring, Silole ring, benzosilol ring, dibenzosilol ring, borol ring, benzoborol ring, dibenzoborol ring, pyrazole ring, imidazole ring, oxadiazole ring, carbazole ring, pyrroloimidazole , Pyrrolopyrazole ring, pyrrolopyrrole ring, thienopyrrole ring, thienothiophene ring, furopyrrole ring, furofuran ring, thienofuran ring, benzoisoxazole ring, benzoisothiazole ring, benzimidazole ring, triazine ring, cinnoline ring, phenanthridine ring, Perimidine ring, quinazolinone ring, isobenzofuran ring, isoindole ring, indolizine ring, chromene ring, benzopyran ring, xanthene ring, quinolidine ring, phenanthridine ring, naphthyridine ring, indazole ring, phthalazine ring, purine ring, pteridine ring, Examples include a heteroaromatic ring such as a thianthrene ring, a phenoxathiin ring, a phenoxazine ring, a phenothiazine ring, and a phenazine ring.

  As Ar1 and Ar2, an aromatic hydrocarbon ring is preferable, and a benzene ring, a naphthalene ring, and an anthracene ring are more preferable.

  The groups Ar1 and Ar2 may have a substituent. Examples of the substituent include an alkyl group, an alkoxy group, an alkylthio group, an aryl group, an aryloxy group, an arylthio group, an arylalkyl group, an arylalkoxy group, Arylalkylthio group, arylalkenyl group, arylalkynyl group, amino group, substituted amino group, silyl group, substituted silyl group, silyloxy group, substituted silyloxy group, halogen atom, acyl group, acyloxy group, imino group, amide group, imide group , Carboxyl group, substituted carboxyl group, cyano group, monovalent heterocyclic group and the like.

  In the polymer compound, the content ratio of the unit represented by the above formula (1) is preferably 5 to 50%, more preferably 10 to 50% in terms of the monomer charging ratio in order to improve the efficiency of the organic photoelectric conversion element. 20 to 50% is more preferable. The monomer charge ratio means (number of moles of monomer for constituting unit represented by the above formula / number of moles of all monomers). If it is less than 5% or exceeds 50%, the conversion efficiency may decrease when used in the photoelectric conversion layer of the organic photoelectric conversion element.

  In order to improve the efficiency of the organic photoelectric conversion element, as R1 and R2, a polymer compound in which R1 is a hydrogen atom is preferable, and R1 is a hydrogen atom, and carbon having 2 or less hydrogen atoms to which R2 is bonded. High molecular compounds that are atoms are more preferred. Furthermore, a polymer compound in which R1 is a hydrogen atom and R2 is bonded to a carbon atom having 1 or less hydrogen atoms is more preferable, R1 is a hydrogen atom, and R2 is bonded to a carbon atom having 0 hydrogen atoms. Certain compounds are most preferred.

  Note that the number of hydrogen atoms to which R2 is bonded is a carbon atom having 2 or less (or 1 or less, 0) that R2 is a substituent having a free carbon and the number of hydrogen atoms bonded to the free carbon. Is a substituent of 2 or less. In other words, R2 is a monovalent group having a free valence from a carbon atom (a carbon atom bonded to a trimethyl structure), and the number of hydrogen atoms bonded to the carbon atom is 2 or less. Means a valent group.

In addition to the repeating unit represented by the formula (1), the polymer compound preferably contains at least one repeating unit having a donor property and an acceptor property. Although the repeating unit having donor properties and acceptor properties is not particularly limited, units cited from the above-mentioned Chem. Rev., 2009, 109, 5868-5923, etc. can be applied. Preferably, for example, a unit represented by the following formulas (2) to (27) is included. In addition, in Formula (27), n is an integer greater than or equal to 1, Preferably it is 1-10, More preferably, it is 2-6.

（ただし、Ｒ^１〜Ｒ^１１は、水素原子、炭素数１〜２２個の直鎖、環状若しくは分岐アルキル基又は炭素数２〜３０個のアリール基若しくはヘテロアリール基を表し、ａ、ｂ及びｃは、１以上の整数、好ましくは１〜４の整数を表す。）で表される置換基を挙げることができ、それぞれは同一であっても異なっていてもよい。 The substituent R included in the units represented by the above formulas (2) to (27) is a group selected from the group consisting of hydrogen and a monovalent group, and is not particularly limited. For example, —R ¹ , —OR ² , —SR ³ , —OCOR ⁴ , —COOR ⁵ , —SiR ⁶ R ⁷ R ⁸ or a polyether

^(Wherein, R 1 ^{to R 11} represents a hydrogen atom, a linear, cyclic or branched alkyl group or a number of 2 to 30 carbon atoms an aryl group or heteroaryl group having 1 to 22 carbon atoms, a, b and c Represents an integer of 1 or more, preferably an integer of 1 to 4.), each of which may be the same or different.

  When the polymer compound is a copolymer, that is, when the polymer compound contains a repeating unit other than the repeating unit represented by the formula (1), for example, a repeating unit having a donor property and an acceptor property, the polymer compound May be alternating, random, block, or graft copolymers.

  The number average molecular weight of the polymer compound is preferably 1,000 to 500,000. From the viewpoint of easy handling of the polymer compound and improvement of the efficiency of the organic photoelectric conversion element, the molecular weight is more preferably 2,500 to 100,000. The number average molecular weight can be measured by gel permeation chromatography (GPC) using a standard polystyrene calibration curve.

As a method for producing a polymer compound, a monomer having a reactive substituent is used, a method of polymerization using a nickel catalyst or a palladium catalyst such as a Suzuki coupling reaction, a method of polymerization using a Grignard reaction, a Kumada-Tamao coupling reaction Examples include a method of polymerizing with a zero-valent nickel complex such as a method of polymerizing with an oxidizing agent such as FeCl _3, a method of electrochemically oxidatively polymerizing, or a method of decomposing an intermediate polymer having an appropriate leaving group. The Examples of the reactive substituent include a group that participates in bond formation by a condensation reaction such as a halogen atom or a borate ester.

The monomer having a reactive substituent constituting the unit represented by the formula (1) is an alkylating agent X-CH ₂ -Ar 1 -Y 1 and / or X using a malonic acid diester or a derivative thereof as a raw material. It can be obtained by alkylation with —CH ₂ —Ar ₂ —Y 2 (X = halogen, Y 1 and Y 2 = reactive substituents) and subsequent decarboxylation reaction. Furthermore, it can also be obtained using an α, α-dialkylated malonic acid diester obtained by alkylation of a malonic acid diester or an α, α-dialkylacetic acid ester obtained by decarboxylation as an intermediate. Can do.

Alternatively, the monomer having a reactive substituent constituting the unit represented by the formula (1) is an alkylating agent X—CH ₂ —Ar 1 —Y 1 and / or an acetoacetate ester or a derivative thereof. Alternatively, it can be obtained by alkylation with X—CH ₂ —Ar ₂ —Y 2 (X = halogen, Y 1 and Y 2 = reactive substituents) followed by decarboxylation. Furthermore, it can also be obtained by using a synthesis method in which an α, α-dialkylated acetoacetate ester obtained by alkylation or an α, α-dialkylketone obtained by decarboxylation is used as an intermediate.

  The polymer compound is used for an organic photoelectric conversion element, and since its purity affects the performance of the element such as photoelectric conversion efficiency, it is preferable to remove impurities as much as possible.

  The method for removing impurities from the polymer compound is not particularly limited, but column chromatography method, recrystallization method, sublimation method, reprecipitation method, Soxhlet extraction method, molecular weight fractionation method by GPC (gel permeation chromatography), A filtration method, an ion exchange method, a chelate method, or the like can be used. Of these, reprecipitation, Soxhlet extraction, and molecular weight fractionation by GPC (gel permeation chromatography) are preferably used to remove low molecular weight components, and reprecipitation or A chelate method or an ion exchange method is preferably used. A plurality of these methods may be combined.

[Configuration of organic photoelectric conversion element]
Next, the configuration of the organic photoelectric conversion element will be described. An organic photoelectric conversion element generally has at least a positive electrode and a negative electrode, and a photoelectric conversion layer between them. The organic photoelectric conversion element may further have a buffer layer. FIG. 1 is a schematic diagram illustrating an example of an organic photoelectric conversion element according to an embodiment of the present invention. In FIG. 1, 1 is a photoelectric conversion layer, 2 is a positive electrode, 3 is a negative electrode, 4 is a buffer layer, and 5 is a substrate. A layer containing a polymer compound containing a repeating unit represented by formula (1) can be used for the photoelectric conversion layer and the buffer layer.

[Photoelectric conversion layer]
In an example of the organic photoelectric conversion element, the photoelectric conversion layer 1 includes a polymer compound including a repeating unit represented by the formula (1). Depending on whether the polymer compound further contains a repeating unit having a donor property (electron-donating property) or a repeating unit having an acceptor property (electron-accepting property), the polymer compound is electron-donated. It can be used as an organic material or an electron-accepting organic material. The electron donating organic material and the electron accepting organic material may be mixed or laminated. When they are mixed, the electron-donating organic material and the electron-accepting organic material are compatible or phase-separated at the molecular level. The domain size of this phase separation structure is not particularly limited, but is usually 1 nm or more and 50 nm or less. When laminated, the layer having an electron-donating organic material exhibiting p-type semiconductor characteristics is preferably on the positive electrode side, and the layer having an electron-accepting organic material exhibiting n-type semiconductor characteristics is preferably on the negative electrode side. In particular, from the viewpoint of conversion efficiency, it is preferable that an electron-donating organic material and an electron-accepting organic material are mixed.

  The thickness of the photoelectric conversion layer is preferably 5 nm to 500 nm, more preferably 30 nm to 300 nm.

  Further, the photoelectric conversion layer may contain an electron-donating organic material (p-type organic semiconductor) and / or an electron-accepting organic material (n-type organic semiconductor) other than the above-described polymer compound.

  Examples of the electron-donating organic material (p-type organic semiconductor) that can be used here include a polythiophene polymer, a poly-p-phenylene vinylene polymer, a poly-p-phenylene polymer, and a polyfluorene heavy polymer. Conjugated polymers such as polymers, polypyrrole polymers, polyaniline polymers, polyacetylene polymers, polythienylene vinylene polymers, H2 phthalocyanine (H2Pc), copper phthalocyanine (CuPc), zinc phthalocyanine (ZnPc), etc. Phthalocyanine derivatives, porphyrin derivatives, N, N′-diphenyl-N, N′-di (3-methylphenyl) -4,4′-diphenyl-1,1′-diamine (TPD), N, N′-dinaphthyl Tria such as -N, N'-diphenyl-4,4'-diphenyl-1,1'-diamine (NPD) Low molecular organic compounds such as uramine derivatives, carbazole derivatives such as 4,4′-di (carbazol-9-yl) biphenyl (CBP), oligothiophene derivatives (terthiophene, quarterthiophene, sexithiophene, octithiophene, etc.) Can be mentioned.

  Examples of the electron-accepting organic material (n-type organic semiconductor) include 1,4,5,8-naphthalene tetracarboxyl dianhydride (NTCDA), 3,4,9,10-perylene tetracarboxyl dianhydride (PTCDA). ), 3,4,9,10-perylenetetracarboxylic bisbenzimidazole (PTCBI), N, N′-dioctyl-3,4,9,10-naphthyltetracarboxydiimide (PTCDI-C8H), 2- (4 -Biphenylyl) -5- (4-t-butylphenyl) -1,3,4-oxadiazole (PBD), 2,5-di (1-naphthyl) -1,3,4-oxadiazole (BND) Oxazole derivatives such as 3- (4-biphenylyl) -4-phenyl-5- (4-tert-butylphenyl) -1,2 Triazole derivatives such as 4-triazole (TAZ), phenanthroline derivatives, phosphine oxide derivatives, fullerene compounds (unsubstituted ones including C60, C70, C76, C78, C82, C84, C90, C94, [6, 6 ] -Phenyl-C61-butyric acid methyl ester ([6,6] -PCBM), [5,6] -Phenyl-C61-butyric acid methyl ester ([5,6] -PCBM), [6,6 ] -Phenyl-C61-butyric acid hexyl ester ([6,6] -PCBH), [6,6] -Phenyl-C61-butyric acid dodecyl ester ([6,6] -PCBD), Phenyl-C71- Butyric acid methyl ester (PC70BM), phenyl-C85-butyrica Tsu like de methyl ester (PC84BM)), carbon nanotubes (CNT), poly -p- phenylene vinylene-based polymer derivatives obtained by introducing cyano group into (CN-PPV) and the like. Among these, fullerene compounds are preferably used because of their high charge separation speed and electron transfer speed.

  The content ratio (weight fraction) of the electron donating organic material and the electron accepting organic material is not particularly limited, but the weight fraction of the electron donating organic material: electron accepting organic material is 1 to 99:99 to 1. It is preferable that it is a range, More preferably, it is the range of 10-90: 90-10, More preferably, it is the range of 20-60: 80-40. It is preferable to use a mixture of an electron-donating organic material and an electron-accepting organic material. Although it does not specifically limit as a mixing method, After adding to a solvent in a desired ratio, the method of making it melt | dissolve in a solvent combining 1 type or multiple types of methods, such as a heating, stirring, and ultrasonic irradiation, is mentioned. . When the photoelectric conversion layer is composed of a single layer, the above-described content ratio is the content ratio of the electron-donating organic material and the electron-accepting organic material included in the single layer, and the photoelectric conversion layer has a laminated structure of two or more layers. In the case, it means the content ratio of the electron-donating organic material and the electron-accepting organic material in the entire photoelectric conversion layer.

[electrode]
Examples of the positive electrode and negative electrode materials include conductive metal oxide films and translucent metal thin films. 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, metals such as lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, strontium, barium, aluminum, scandium, vanadium, zinc, yttrium, indium, cerium, samarium, europium, terbium, ytterbium, and two of them One or more alloys, or one or more of them and an alloy of one or more of gold, silver, platinum, copper, manganese, titanium, cobalt, nickel, tungsten, tin, graphite, or a graphite intercalation compound are used. It is done. Examples of the alloy include magnesium-silver alloy, magnesium-indium alloy, magnesium-aluminum alloy, indium-silver alloy, lithium-aluminum alloy, lithium-magnesium alloy, lithium-indium alloy, calcium-aluminum alloy and the like.

  In the organic photoelectric conversion element of the embodiment of the present invention, it is preferable that either the positive electrode or the negative electrode has light transmittance.

[Buffer layer]
Examples of the buffer layer include a charge transport layer, that is, a hole transport layer and an electron transport layer. As a material used for the buffer layer, in addition to the above-described polymer compound, there are the above-described electron-donating organic material, electron-accepting organic material, and materials described below.

Specifically, a buffer layer (hole transport layer) may be provided between the positive electrode and the photoelectric conversion layer. As a material for forming the hole transport layer, conductive polymers such as polythiophene polymers, poly-p-phenylene vinylene polymers, polyfluorene polymers, phthalocyanine derivatives (H ₂ Pc, CuPc, ZnPc, etc.) ), Low molecular organic compounds exhibiting p-type semiconductor properties such as porphyrin derivatives are preferably used. In particular, polyethylenedioxythiophene (PEDOT), which is a polythiophene polymer, or PEDOT to which polystyrene sulfonate (PSS) is added is preferably used. The thickness of the hole transport layer is preferably from 0.2 nm to 600 nm, more preferably from 0.2 nm to 200 nm. The hole transport layer may be doped with various metal oxides such as MnOx, WO ₃ , SnO ₂ , In ₂ O ₃ , and ZnO.

  Further, a buffer layer (electron transport layer) may be provided between the negative electrode and the photoelectric conversion layer. The material for forming the electron transport layer is not particularly limited, but the above-described electron-accepting organic materials (NTCDA, PTCDA, PTCDI-C8H, oxazole derivatives, triazole derivatives, phenanthroline derivatives, phosphine oxide derivatives, fullerene compounds, An organic material exhibiting n-type semiconductor characteristics such as CNT and CN-PPV is preferably used. In addition, fine particles of an inorganic semiconductor such as an alkali metal such as lithium fluoride, a halide of an alkaline earth metal, an oxide, or titanium oxide may be used. The thickness of the electron transport layer is preferably from 0.2 nm to 600 nm, more preferably from 0.2 nm to 200 nm.

[Method for producing organic photoelectric conversion element]
Next, the manufacturing method of the photoelectric conversion element which is embodiment of this invention is demonstrated. The manufacturing method of a photoelectric conversion element has the process of forming the layer containing the above-mentioned high molecular compound by apply | coating the solution containing the above-mentioned high molecular compound. An example of the manufacturing method will be specifically described. First, a transparent electrode such as ITO (corresponding to a positive electrode in this case) is formed on a substrate such as plastic or glass by a sputtering method or the like. Next, a polymer compound containing the repeating unit represented by the formula (1) and, if necessary, a material for a photoelectric conversion element containing another electron-donating organic material and / or an electron-accepting organic material are dissolved in a solvent. A solution is made and applied on a transparent electrode to form a photoelectric conversion layer. The solvent used at this time is preferably an organic solvent. For example, methanol, ethanol, butanol, toluene, xylene, o-chlorophenol, acetone, ethyl acetate, ethylene glycol, tetrahydrofuran, dichloromethane, chloroform, dichloroethane, chlorobenzene, dichlorobenzene, Examples include chlorobenzene, chloronaphthalene, dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, and γ-butyrolactone. Two or more of these may be used.

  For the formation of the photoelectric conversion layer, any coating method such as spin coating, blade coating, slit die coating, screen printing coating, bar coater coating, mold coating, printing transfer method, dip-up method, ink jet method, spray method, etc. can be used. The formation method may be selected according to the characteristics of the photoelectric conversion layer to be obtained, such as film thickness control and orientation control. Further, it is possible to use a vacuum deposition method instead of the coating method. For example, when spin coating is performed, the photoelectric conversion element material may have a concentration of 1 to 20 g / L (the weight of the photoelectric conversion element material with respect to the volume of the solution containing the photoelectric conversion element material and the solvent). it can. Moreover, it is possible to obtain a homogeneous photoelectric conversion layer having a thickness of 5 to 200 nm by appropriately adjusting the concentration. In order to remove the solvent, the formed photoelectric conversion layer may be subjected to an annealing treatment under reduced pressure or under an inert atmosphere (nitrogen or argon atmosphere). A preferable temperature for the annealing treatment is 40 ° C to 300 ° C, more preferably 50 ° C to 200 ° C. Further, by performing the annealing process, the effective area where the stacked layers permeate and contact each other at the interface increases, and the short-circuit current can be increased. This annealing treatment may be performed after the formation of the negative electrode.

  Next, a metal electrode such as Al (corresponding to a negative electrode in this case) is formed on the photoelectric conversion layer by vacuum deposition or sputtering. When the metal electrode is vacuum-deposited using a low molecular organic material for the electron transport layer, it is preferable that the metal electrode is continuously formed while maintaining the vacuum.

  When a hole transport layer is provided between the positive electrode and the photoelectric conversion layer, for example, a material for forming the hole transport layer is applied on the positive electrode by a spin coating method, a bar coating method, a blade casting method, or the like. Thereafter, the solvent is removed using a vacuum thermostat or a hot plate to form a hole transport layer. In the case of using a low molecular organic material such as a phthalocyanine derivative or a porphyrin derivative, it is also possible to apply a vacuum vapor deposition method using a vacuum vapor deposition machine.

  When an electron transport layer is provided between the photoelectric conversion layer and the negative electrode, for example, a material for forming a desired electron transport layer is formed on the photoelectric conversion layer by spin coating, bar coating, blade casting, spraying, and the like. After coating by a method or the like, the solvent is removed using a vacuum thermostat or a hot plate to form an electron transport layer. When using a low molecular weight organic material such as a phenanthroline derivative or C60, it is also possible to apply a vacuum deposition method using a vacuum deposition machine.

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

[Example 1]
<Synthesis of Polymer Compound 1>
<Adjustment of Pd catalyst>
In a glove box under a nitrogen atmosphere, tris (dibenzylideneacetone) dipalladium (73.2 mg, 80 μmol) was weighed into a sample tube at room temperature, anisole (15 mL) was added, and the mixture was stirred for 30 minutes. Similarly, tri-tert-butylphosphine (129.6 mg, 640 μmol) was weighed in a sample tube, anisole (5 mL) was added, and the mixture was stirred for 5 minutes. These solutions were mixed and stirred at room temperature for 30 minutes to form a catalyst.

<Synthesis of Monomer 1>

  A mixture of anhydrous cerium (III) chloride (4.44 g, 18.0 mmol) and tetrahydrofuran (48 mL) was stirred at room temperature for 12 hours. This was cooled to −78 ° C., an ether solution of methyl lithium (11.3 mL, 1.6 M, 18.0 mmol) was added, and the mixture was stirred for 1 hour.

  After adding a solution of ethyl 2- (4-bromobenzyl) -3- (4-bromophenyl) propanoate (2.56 g, 6.00 mmol) in tetrahydrofuran (6 mL) at −78 ° C. to the obtained mixture. Stir for 2 hours. The mixture was quenched with 0.1 M aqueous acetic acid (10 mL) and extracted with ethyl acetate. The obtained organic layer was washed with water, dried over anhydrous sodium sulfate, and filtered. To the residue obtained by concentrating the filtrate under reduced pressure, pyridine (12 mL) and triethylsilyl chloride (1.3 mL, 7.5 mmol) were added at room temperature to obtain a mixture.

  The mixture was stirred at 60 ° C. for 20 hours. After the mixture was cooled to room temperature, a saturated aqueous ammonium chloride solution was added to stop the reaction. The organic layer was separated from the mixture and the aqueous layer was extracted with hexane. The obtained organic layer was washed with water, dried over anhydrous magnesium sulfate, and filtered. The residue obtained by concentrating the filtrate under reduced pressure was purified by silica gel column chromatography (hexane) to obtain Compound 1 (3.00 g, 5.7 mmol) as a colorless liquid in a yield of 95%.

Under a nitrogen atmosphere, a 500 mL four-necked flask was charged with compound 1 (11.00 g, 20.9 mmol), bispinacolatodiboron (12.13 g, 47.8 mmol), potassium acetate (14.22 g, 145 mmol), and DME ( 293 mL) and degassed with nitrogen for 30 minutes. Pd (dppf) Cl ₂ .CH ₂ Cl ₂ (1.51 g, 1.85 mmol) was added thereto, and the mixture was heated and stirred at an internal temperature of 87 ° C. for 4 hours. After completion of the reaction, water (200 mL) was poured and extracted with ethyl acetate (200 mL × 3 times). The organic layer was washed with saturated brine (200 mL × 1) and then dried over magnesium sulfate (20 g). After the solvent was distilled off from the organic layer under reduced pressure, it was purified by silica gel column chromatography (hexane, then hexane / ethyl acetate = 10/1) using silica gel 60N (manufactured by Kanto Chemical Co., Inc.). A yellow solid (10.21 g) was obtained. When recrystallized from ethanol (300 mL), 7.00 g (yield 54%) of monomer 1 was obtained as a white solid.

<Synthesis of Polymer Compound 1>

  Monomer 1 (1.25 mmol), monomer 2 (1.25 mmol) and anisole (6 mL) were added to a three-necked round bottom flask, and a further prepared Pd catalyst solution (2 mL) was added. After stirring for 30 minutes, 10% tetraethylammonium hydroxide aqueous solution (10 mL) was added. All solvents were used after degassing with nitrogen bubble for more than 30 minutes. This mixture was heated to reflux for 6 hours. All the operations so far were performed under a nitrogen stream.

  After completion of the reaction, the organic layer was washed with water, and the organic layer was poured into methanol-water (9: 1). The resulting precipitate was suction filtered and washed with methanol-water (9: 1). The resulting precipitate was dissolved in toluene and reprecipitated from methanol. The obtained precipitate was filtered by suction, dissolved in toluene, and triphenylphosphine, polymer-bound on styrene-divinylbenzene copolymer (Strem Chemicals, 500 mg per 100 mg of polymer) was added and stirred overnight. After the stirring, Triphenylphosphine, polymer-bound on styrene-divinylbenzene copolymer and insoluble matter were removed by filtration, and the filtrate was concentrated with a rotary evaporator. The residue was dissolved in toluene and then reprecipitated from methanol-acetone (8: 3). The resulting precipitate was filtered by suction and washed with methanol-acetone (8: 3). The obtained precipitate was vacuum-dried to obtain a polymer. The molecular weight was measured by GPC (polystyrene conversion) using THF as an eluent. Mw = 5600 and Mn = 3900.

[Example 2]
<Synthesis of Polymer Compound 2>

  Polymer compound 2 was synthesized in the same manner except that monomer 2 was changed to monomer 3. The molecular weight was Mw = 27000 and Mn = 10000.

[Example 3]
<Creation of organic photoelectric conversion element>
A PEDOT: PSS dispersion (Stark Vitec, AI4083 LVW142) was spin-coated at 1500 min ⁻¹ on a glass substrate patterned with ITO to a width of 1.6 mm, and 200 ° C./10 minutes in air on a hot plate. A buffer layer (40 nm) was formed by heating and drying. The subsequent operation was performed in a dry nitrogen environment.
Next, a mixed solution in which 20 mg of each of the polymer compound 1 and PCBM were dissolved in 1 mL of chlorobenzene was spin-coated to form a photoelectric conversion layer (film thickness 100 nm). Next, the glass substrate on which the photoelectric conversion layer was formed was transferred into a vacuum vapor deposition machine, and Al (film thickness 100 nm) was vapor-deposited to produce an organic photoelectric conversion element.
The obtained organic photoelectric conversion element was irradiated with AM1.5G (100 mW / cm ² ) pseudo-sunlight, current-voltage characteristics (JV characteristics) were measured, and energy conversion efficiency was determined. The open circuit voltage was 0.88V, and the energy conversion efficiency was 0.75%.

[Example 4]
<Creation of organic photoelectric conversion element>
An organic photoelectric conversion device was prepared by the same method except that the polymer compound 1 was changed to 2, and the energy conversion efficiency was determined. The open circuit voltage was 0.85 V and the energy conversion efficiency was 0.55%.

1 Photoelectric conversion layer 2 Electrode 3 Electrode 4 Buffer layer 5 Substrate

Claims (10)

The organic photoelectric conversion element which has a layer containing the high molecular compound containing the repeating unit represented by following formula (1).

(In the formula (1), R1 and R2 are each independently a group selected from the group consisting of hydrogen and a substituent consisting of C, H and / or X (X is a heteroatom)). Yes,
Ar1 and Ar2 are each independently a group selected from the group consisting of a divalent aromatic ring consisting of C and H, and a divalent aromatic ring consisting of C, H and X (X is a heteroatom). It is. )   The organic photoelectric conversion element according to claim 1, wherein R 1 is a hydrogen atom.   The organic photoelectric conversion device according to claim 1, wherein R 1 is a hydrogen atom, and R 2 is a carbon atom having 2 or less hydrogen atoms bonded thereto.   The organic photoelectric conversion device according to any one of claims 1 to 3, wherein R1 is a hydrogen atom, and R2 is a carbon atom having 1 or less hydrogen atoms bonded thereto. The organic photoelectric conversion element according to any one of claims 1 to 4, wherein the polymer compound further contains one or more units represented by formulas (2) to (27).

  The organic photoelectric conversion element according to claim 1, wherein the polymer compound has a number average molecular weight of 1,000 to 500,000.   The number average molecular weight of the said high molecular compound is 2,500-100,000, The organic photoelectric conversion element as described in any one of Claims 1-6.   The organic photoelectric conversion element according to claim 1, wherein the polymer compound is an electron donating organic material.   The layer containing the said high molecular compound is an organic photoelectric converting layer, The organic photoelectric conversion element as described in any one of Claims 1-8. A method for producing the organic photoelectric conversion element according to any one of claims 1 to 9,
The manufacturing method of an organic photoelectric conversion element which has the process of forming the layer containing the said high molecular compound by apply | coating the solution containing the said high molecular compound.

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