JP5791995B2 - Novel compound, photoelectric conversion material and photoelectric conversion element - Google Patents

Description

  The present invention relates to a novel compound, a photoelectric conversion material, a photoelectric conversion layer, a photoelectric conversion element, and an organic thin film solar cell.

In recent years, solar cells (solar power generation) that can be used continuously, do not deplete resources, and have low environmental pollution have been actively studied. Solar cells are roughly classified into Si-based and non-Si-based inorganic solar cells, and dye-sensitized and organic thin-film organic solar cells. Inorganic solar cells generally have high photoelectric conversion efficiency, but have a drawback of high manufacturing cost because high vacuum is required or high-temperature heat treatment is required. On the other hand, since the organic solar cell can be formed by a coating method, a printing method, or the like, the manufacturing cost is low and the film can be formed in a large area. In addition, organic solar cells can also be advantageous in that the elements are lighter than inorganic solar cells. In particular, organic thin-film solar cells are excellent in printing methods and can be easily formed into a film or the like, so that flexible solar cells are also easy.
However, since many organic solar cells have low photoelectric conversion efficiency, increasing the photoelectric conversion efficiency is a problem.

  Currently, P3HT [poly (3-hexylthiophene)], which is a p-type organic semiconductor material, and PCBM [[6, 6], which is an n-type organic semiconductor material, as materials having high photoelectric conversion efficiency in organic thin-film solar cells. ] -Phenyl-C61-butyric acid methyl ester] and a bulk heterojunction made of a mixed material (see Non-Patent Document 1, etc.). Further, many studies have been made to increase the photoelectric conversion efficiency using the material. For example, the photoelectric conversion efficiency is improved by annealing treatment (see Non-Patent Documents 2 and 3, etc.), and a third component is added to P3HT / PCBM. Attempts have been made to include inorganic nanoparticles in the photoelectric conversion layer (see Patent Document 2, etc.), change the layer structure (see Patent Document 3, etc.), and the like.

  If the photoelectric conversion efficiency is improved by adding a third component or higher component to the p-type and n-type organic semiconductor material, it is preferable because it can be easily realized in the production of the element. By adding the agent, there was a disadvantage that the photoelectric conversion efficiency was lowered as compared with the non-added state.

JP 2007-335760 JP 2009-158730 A JP 2009-206273 A

F. Padinger, et al., Adv. Funct. Mater., 13, 85 (2003) M. R-Reyes, et al., Appl. Phys. Lett., 87, 083506 (2005) W. Ma, et al., Adv. Funct. Mater., 15, 1617 (2005)

Accordingly, an object of the present invention is to provide a bulk heterojunction organic thin-film solar cell material having both p-type and n-type organic semiconductor materials (particularly P3HT / PCBM) as a third component or more components. An object of the present invention is to provide a novel compound suitable for a photoelectric conversion material that can improve the photoelectric conversion efficiency without impairing the conventional properties even when added together.
Another object of the present invention is to provide a photoelectric conversion material, a photoelectric conversion layer, a photoelectric conversion element, and an organic thin film solar cell using the novel compound.

  As a result of extensive studies, the present inventors have found that a compound having a specific structure is a bulk heterojunction type organic thin-film solar cell having both p-type and n-type organic semiconductor materials (particularly P3HT / PCBM). It is found that the photoelectric conversion efficiency can be improved without impairing the conventional characteristics even if it is added to the material as the third component or with more components, and the compound having the above specific structure is added to the p-type. Knowing that a photoelectric conversion layer formed by forming a photoelectric conversion material added to an organic semiconductor material and an n-type organic semiconductor material exhibits high conversion efficiency, and using this, a photoelectric conversion element and further an organic thin film solar cell It has been found that the above object can be solved by manufacturing.

  The present invention has been made based on the above findings and provides a novel compound represented by the following general formula (1).

（式中、Ａ¹は、１価の芳香族基を表し、Ａ²は、２価の芳香族基を表し、環Ｂ¹は、５〜７員環を表し、ｎは０〜２の整数を表す。）

(In the formula, A ¹ represents a monovalent aromatic group, A ² represents a divalent aromatic group, Ring B ¹ represents a 5- to 7-membered ring, and n represents an integer of 0 to 2. Represents.)

  The present invention also provides a photoelectric conversion material comprising (A) a compound represented by the general formula (1), (B) a p-type organic semiconductor material, and (C) an n-type organic semiconductor material. is there.

  Moreover, this invention provides the photoelectric converting layer obtained by forming into a film the said photoelectric converting material.

  Moreover, this invention provides the photoelectric conversion element which has the said photoelectric converting layer.

  Moreover, this invention provides the organic thin film solar cell which has the said photoelectric conversion element.

  By adopting the above configuration, the novel compound of the present invention is added to a bulk heterojunction organic thin film solar cell material having both p-type and n-type organic semiconductor materials (particularly P3HT / PCBM) as a third component. Even if it is added together with more components, it is useful because high photoelectric conversion efficiency can be realized without impairing conventional characteristics.

FIG. 1A is a cross-sectional view showing an example of the configuration of the photoelectric conversion element of the present invention, FIG. 1B is a cross-sectional view showing another example of the configuration of the photoelectric conversion element of the present invention, FIG.1 (c) is sectional drawing which shows another example of a structure of the photoelectric conversion element of this invention.

  Hereinafter, the novel compound, photoelectric conversion material, photoelectric conversion layer, photoelectric conversion element, and organic thin-film solar cell of the present invention will be described in detail based on preferred embodiments.

<New compound>
The novel compound of the present invention is represented by the above general formula (1).
Examples of the monovalent aromatic group which general formula A ¹ in (1) represents an aromatic substituted carbon atoms which may 6-20 hydrocarbon ring group or a substituted carbon atoms which may 3-20 The aromatic heterocyclic group of these is mentioned.
Examples of the aromatic hydrocarbon ring group include an unsubstituted aromatic hydrocarbon ring group or an aromatic hydrocarbon ring group substituted with an aliphatic hydrocarbon group (provided that the number of carbon atoms including the aliphatic hydrocarbon group is 6). The aromatic heterocyclic group is an unsubstituted aromatic heterocyclic group or an aromatic heterocyclic group substituted with an aliphatic hydrocarbon group (provided that the aliphatic hydrocarbon group is And those having 3 to 20 carbon atoms).

  Examples of the unsubstituted aromatic hydrocarbon ring group include phenyl, naphthyl, biphenyl, terphenyl, fluoryl, pyrenyl and the like.

As the aromatic hydrocarbon ring group substituted with the above aliphatic hydrocarbon group, for example, the above-mentioned unsubstituted aromatic hydrocarbon ring group is substituted with 1 to 3 aliphatic hydrocarbon groups having 1 to 5 carbon atoms. Examples of the aliphatic hydrocarbon group having 1 to 5 carbon atoms include methyl, ethyl, propyl, isopropyl, butyl, s-butyl, t-butyl, isobutyl, amyl, isoamyl, t- Examples thereof include linear or branched alkyl groups such as amyl.
The aliphatic hydrocarbon group having 1 to 5 carbon atoms is —O—, —COO—, —OCO—, —CO—, —S—, —SO—, —SO ₂ —, —NR— or —C. ═C— may be interrupted, R represents an aliphatic hydrocarbon group having 1 to 5 carbon atoms, and examples thereof include 1 carbon atom that may substitute for the aromatic hydrocarbon ring group. Groups exemplified in the description of the aliphatic hydrocarbon group of -5, and when the group interrupting the aliphatic hydrocarbon group having 1 to 5 carbon atoms contains a carbon atom, carbon including the interrupted group The number of atoms is 1-5.

  Examples of the unsubstituted aromatic heterocyclic group include furanyl, thiophenyl, chromenyl, benzothiophenyl, bifuranyl, terfuranyl, bithiophenyl, terthiophenyl, selenophenyl, bisenophenyl, terselenophenyl, and the like.

  Examples of the aromatic heterocyclic group substituted with the aliphatic hydrocarbon group include those in which the unsubstituted aromatic heterocyclic group is substituted with 1 to 3 aliphatic hydrocarbon groups having 1 to 5 carbon atoms. The aliphatic hydrocarbon group having 1 to 5 carbon atoms is the same group as the aliphatic hydrocarbon group having 1 to 5 carbon atoms that may replace the aromatic hydrocarbon ring group. .

The aromatic hydrocarbon ring group or aromatic heterocyclic group listed above may be further substituted, and the group that may substitute the aromatic hydrocarbon ring group and aromatic heterocyclic group is a fluorine atom. , A chlorine atom, a bromine atom, an iodine atom, a cyano group, a nitro group, a hydroxyl group, a thiol group, a —NRR ′ group and the like, and R and R ′ are a monovalent aromatic group represented by A ¹ or the aromatic The same group as the C1-C5 aliphatic hydrocarbon group which may substitute a hydrocarbon ring group is represented.

Among the monovalent aromatic groups represented by A ¹ exemplified above, an unsubstituted aromatic heterocyclic group is preferable, a monovalent thiophene ring such as thiophenyl, benzothiophenyl, bithiophenyl or terthiophenyl, or selenophenyl. It is more preferable that it is a monovalent selenophene ring such as biselenophenyl or terselenophenyl in terms of excellent characteristics when used in a photoelectric conversion element or the like, and when it is thiophenyl, bithiophenyl, or terthiophenyl, It is particularly preferable because the raw materials are easily available.

Examples of the divalent aromatic group represented by A ² in the general formula (1), a hydrogen atom from a monovalent aromatic group in which the A ¹ is indicated include one desorbed groups, among them the A ¹ and For the same reason, an unsubstituted aromatic heterocyclic group is preferred, and more preferred is a divalent thiophene ring such as divalent thiophene, benzothiophene, bithiophene or terthiophene, or a divalent selenophene ring such as selenophene. More preferably, it is more preferably divalent thiophene, bithiophene, or terthiophene.

Examples of the 5- to 7-membered ring represented by the ring B ¹ in the general formula (1) include aliphatic hydrocarbon rings, that is, cyclopentyl, cyclohexyl, and cycloheptyl. These rings have 1 to 5 carbon atoms. 1 to 4 positions may be substituted with an aliphatic hydrocarbon group, and the aliphatic hydrocarbon group having 1 to 5 carbon atoms may have 1 to 5 carbon atoms which may replace the aromatic hydrocarbon ring group. 5 is the same group as the aliphatic hydrocarbon group, and in particular, from the viewpoint of coplanarity and solubility, it is substituted at 1 or 2 positions by unsubstituted cyclopentyl or an aliphatic hydrocarbon group having 1 to 5 carbon atoms. Cyclopentyl is preferred.

Further, when ring B ¹ is substituted with an aliphatic hydrocarbon group having 1 to 5 carbon atoms, from the viewpoint of solubility and coplanarity, the ring is represented by the following general formula (1) -1. It is preferable that one (X ¹ ) of carbon atoms therein is substituted with an aliphatic hydrocarbon group (R ¹ and R ² ) having 1 to 5 carbon atoms, particularly 1 carbon atom. It is particularly preferred that the aliphatic hydrocarbon groups of ˜5 are the same group.

（式中、Ａ¹、Ａ²及びｎは、上記一般式（１）と同様であり、環Ｂ¹'は、５〜７員環を表し、Ｘ¹は炭素原子を表し、Ｒ¹及びＲ²は、それぞれ独立して炭素原子数１〜５の脂肪族炭化水素基を表し、該炭素原子数１〜５の脂肪族炭化水素基は、−Ｏ−、−ＣＯＯ−、−ＯＣＯ−、−ＣＯ−、−Ｓ−、−ＳＯ−、−ＳＯ₂−、−ＮＲ−又は−Ｃ＝Ｃ−で中断されていてもよく、Ｒは炭素原子数１〜５の脂肪族炭化水素基を表す。）

(In the formula, A ¹ , A ² and n are the same as those in the general formula (1), ring B ¹ ′ represents a 5- to 7-membered ring, X ¹ represents a carbon atom, R ¹ and R ² independently represents an aliphatic hydrocarbon group having 1 to 5 carbon atoms, and the aliphatic hydrocarbon group having 1 to 5 carbon atoms is represented by —O—, —COO—, —OCO—, — CO—, —S—, —SO—, —SO ₂ —, —NR— or —C═C— may be interrupted, and R represents an aliphatic hydrocarbon group having 1 to 5 carbon atoms. )

Among the novel compounds represented by the above general formula (1), A ¹ or A in the above general formula (1) from the viewpoint of excellent characteristics when used in a photoelectric conversion element or the like, or easy acquisition of raw materials. A compound in which at least one of ² has a thiophene ring, particularly a compound in which both A ¹ and A ² have a thiophene ring is preferable.

  Specific examples of the novel compound of the present invention represented by the general formula (1) include the following compound No. 1-No. 24, but is not limited to these compounds.

Although the manufacturing method of the compound represented by the said General formula (1) is not specifically limited, For example, it can manufacture as follows according to following Reaction Formula (A)-(U).
That is, in the reaction formula (a), the intermediate (2) is obtained by Sonogashira-Hagiwara cross coupling between the bisalkyne (11) and 2 equivalents of the aryl halide (12).
In addition, the same reaction between the bisalkyne body (11) and the equivalent amount of the aryl halide (12) was performed to obtain an intermediate (13), and then the dihalogenated aryl (14) and 2 equivalents of the intermediate (13) were reacted. By doing this, the intermediate (3) is obtained.
Further, the intermediate (13) is reacted with an equivalent amount of the dihalogenated aryl (14) to form an intermediate (15), and then the bisalkyne (11) is reacted with 2 equivalents of the intermediate (15) to obtain an intermediate. A body (4) is obtained. Hereinafter, intermediates (2) to (4) are collectively represented by the following general formula (5) (hereinafter also referred to as intermediate (5)). The intermediate (5) represents intermediate (2) when n = 0, represents intermediate (3) when n = 1, and represents intermediate (4) when n = 2. .
Next, in the reaction formula (a), Cp ₂ ZrCl ₂ is reduced with 2 equivalents of n-BuLi, and the intermediate (5) is reacted therewith to obtain the zirconacyclopentadiene derivative (6). .
Subsequently, in the reaction formula (c), the novel compound represented by the above general formula (1) of the present invention is obtained by reacting the zirconacyclopentadiene derivative (6) with sulfur chloride (S ₂ Cl ₂ ). I can do it.

（式中、Ａ¹及びＡ²は、上記一般式（１）と同様の基であり、Ｚ¹は、置換基を有していてもよい炭素原子数３〜３０の直鎖脂肪族炭化水素基を表し、Ｘは、塩素原子、臭素原子又はヨウ素原子を表す。）

(In the formula, A ¹ and A ² are the same groups as in the general formula (1), and Z ¹ is a linear aliphatic hydrocarbon having 3 to 30 carbon atoms which may have a substituent. And X represents a chlorine atom, a bromine atom or an iodine atom.)

（式中、Ａ¹、Ａ²、環Ｂ¹及びｎは、上記一般式（１）と同様の基を表し、Ｚ¹は、上記一般式（２）〜（４）と同様の基を表し、Ｃｐはシクロペンタジエンを表す。）

(In the formula, A ¹ , A ² , ring B ¹ and n represent the same groups as in the general formula (1), and Z ¹ represents the same groups as in the general formulas (2) to (4). , Cp represents cyclopentadiene.)

（式中、Ａ¹、Ａ²、環Ｂ¹及びｎは、上記一般式（１）と同様の基を表し、Ｃｐは上記一般式（６）と同様の基を表す。）

(In the formula, A ¹ , A ² , ring B ¹ and n represent the same group as in the general formula (1), and Cp represents the same group as in the general formula (6).)

  The novel compound of the present invention represented by the above general formula (1) is used as a photoelectric conversion material to be described below, as well as a dye for an optical recording layer such as DVD-R; a liquid crystal display (LCD), a plasma display panel Dyes for optical filters used in image display devices such as (PDP), cathode ray tube display devices (CRT), fluorescent display tubes, or field emission displays; colorants such as color toners, inkjet inks, paint pigments; LEDs Illumination, electroluminescence device; sensitizer for photoreaction, electrophotographic photosensitive member, color filter material, laser dye, nonlinear optical material, dye for medical examination medicine, or may be used alone as a photoelectric conversion material.

<Photoelectric conversion material>
The photoelectric conversion material of the present invention comprises (A) the compound represented by the general formula (1) of the present invention contained in (B) p-type organic semiconductor material and (C) n-type organic semiconductor material. .

  (B) Examples of p-type organic semiconductor materials include phthalocyanine pigments, indigo or thioindigo pigments, quinacridone pigments, triarylmethane derivatives, triarylamine derivatives, oxazole derivatives, hydrazone derivatives, stilbene derivatives, pyrazoline derivatives, polysilanes Derivatives, polyphenylene vinylene and its derivatives [eg, poly [2-methoxy-5- (2-ethylhexyloxy) -1,4-phenylene vinylene]: MEH-PPV, poly [2-methoxy-5- (3 ′, 7'-dimethyloctyloxy) -1,4-phenylenevinylene]], polythiophene and its derivatives [eg, poly (3-dodecylthiophene), poly (3-hexylthiophene): P3HT, poly (3-octylthiophene)] Poly-N-vinylcarbazo Among these (B) p-type organic semiconductor materials, polythiophene and its derivatives are preferable from the viewpoint of having high carrier mobility as the p-type material, and among them, poly (3-hexylthiophene) : P3HT is particularly preferred. In addition, the compound quoted as an example as a p-type organic-semiconductor material may be used independently, or may be used together.

  (C) As an n-type organic semiconductor material, a perylene pigment, a perinone pigment, a polycyclic quinone pigment, an azo pigment, C60 fullerene, C70 fullerene, and a derivative thereof can be used. For example, tris (8-quinolinolato) aluminum, bis (10-benzo [h] quinolinolato) beryllium, beryllium salt of 5-hydroxyflavone, aluminum salt of 5-hydroxyflavone], oxadiazole derivative [for example, 1,3- Bis [5 ′-(p-tert-butylphenyl) -1,3,4-oxadiazol-2′-yl] benzene], triazole derivatives [eg 3- (4′-tert-butylphenyl) -4 -Phenyl-5- (4 ''-biphenyl) -1,2,4-triazole], phenanthroline derivatives [e.g. 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (basocuproin, BCP)], triazine derivatives, quinoline derivatives, quinoxaline derivatives, diphenylquinone derivatives, nitro-substituted fluorenone derivatives, thiopyrandioxide derivatives, etc. Among these (C) n-type organic semiconductor materials, C60 fullerene, C70 fullerene and derivatives thereof are preferable from the viewpoint of having high carrier mobility and / or high charge separation efficiency as an n-type material. In addition, the compound quoted as an example as an n-type organic-semiconductor material may be used independently, or may be used together.

  Examples of the C60 fullerene, C70 fullerene, and derivatives thereof include the following C1 to C6 compounds. Among them, C1 PCBM (phenyl) is preferable because it has excellent electronic level matching and is easily available. -C61-butyric acid methyl ester) is preferably used.

  The photoelectric conversion material of the present invention in which a p-type organic semiconductor material and an n-type organic semiconductor material are mixed has high charge separation efficiency and good match of the electron level with the compound appearing in the general formula (1). Therefore, a combination of P3HT (p-type) and PCBM (n-type) is particularly preferable.

  In the photoelectric conversion material of the present invention, (A) the weight ratio of the compound represented by the general formula (1) is 100 parts by weight of the total of (B) p-type organic semiconductor material and (C) n-type organic semiconductor material. 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight, and more preferably 1 to 3 parts by weight. (A) When the weight ratio of the compound represented by the general formula (1) is smaller than 0.1 parts by weight, the effect of improving the photoelectric conversion efficiency is small, and when it exceeds 10 parts by weight, the photoelectric conversion efficiency is lowered. It is not preferable. The weight ratio of (B) p-type organic semiconductor material to (C) n-type organic semiconductor material is preferably 30:70 to 70:30 (the former: the latter), and more preferably 40:60 to 60: 40.

Moreover, content of each (A)-(C) component in the photoelectric conversion material of this invention is as follows.
(A) Compound represented by the above general formula (1): preferably 0.5 to 5% by weight, more preferably 1 to 3% by weight
(B) p-type organic semiconductor material: preferably 25 to 70% by weight, more preferably 35 to 60% by weight
(C) n-type organic semiconductor material :: preferably 25 to 70% by weight, more preferably 35 to 60% by weight

  The photoelectric conversion material of this invention should just contain at least 1 type each of (A) the compound represented by the said General formula (1), (B) p-type organic-semiconductor material, and (C) n-type organic-semiconductor material. . Moreover, you may contain 1 type, or 2 or more types of solvent etc. as needed.

  The solvent is not particularly limited as long as it can dissolve or disperse the components (A) to (C). For example, water, alcohol solvent, diol solvent, ketone solvent, ester solvent, Examples include ether solvents, aliphatic or alicyclic hydrocarbon solvents, aromatic hydrocarbon solvents, hydrocarbon solvents having a cyano group, halogenated hydrocarbon solvents, and other solvents. A photoelectric conversion material using a solvent can be used as a coating solution.

  Examples of the alcohol solvent include methanol, ethanol, propanol, isopropanol, 1-butanol, isobutanol, 2-butanol, tertiary butanol, pentanol, isopentanol, 2-pentanol, neopentanol, and third. Pentanol, hexanol, 2-hexanol, heptanol, 2-heptanol, octanol, 2-ethylhexanol, 2-octanol, cyclopentanol, cyclohexanol, cycloheptanol, methylcyclopentanol, methylcyclohexanol, methylcycloheptanol , Benzyl alcohol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl Ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, 2- (N, N-dimethylamino) ethanol, 3 (N, N-dimethylamino) propanol, etc. Can be mentioned.

  Examples of the diol solvent include ethylene glycol, propylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, neopentyl glycol, isoprene glycol ( 3-methyl-1,3-butanediol), 1,2-hexanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,2-octanediol, octanediol (2-ethyl) -1,3-hexanediol), 2-butyl-2-ethyl-1,3-propanediol, 2,5-dimethyl-2,5-hexanediol, 1,2-cyclohexanediol, 1,4-cyclohexanediol 1,4-cyclohexanedimethanol and the like.

  Examples of the ketone solvent include acetone, ethyl methyl ketone, methyl isopropyl ketone, methyl butyl ketone, methyl isobutyl ketone, methyl amyl ketone, methyl hexyl ketone, ethyl butyl ketone, diethyl ketone, dipropyl ketone, diisobutyl ketone, and methyl. Examples include amyl ketone, cyclohexanone, and methylcyclohexanone.

  Examples of the ester solvent include methyl formate, ethyl formate, methyl acetate, ethyl acetate, isopropyl acetate, butyl acetate, isobutyl acetate, second butyl acetate, third butyl acetate, amyl acetate, isoamyl acetate, and third amyl acetate. , Phenyl acetate, methyl propionate, ethyl propionate, isopropyl propionate, butyl propionate, isobutyl propionate, sec-butyl propionate, tert-butyl propionate, amyl propionate, isoamyl propionate, amyl propionate, Phenyl propionate, methyl 2-ethylhexanoate, ethyl 2-ethylhexanoate, propyl 2-ethylhexanoate, isopropyl 2-ethylhexanoate, butyl 2-ethylhexanoate, methyl lactate, ethyl lactate, methyl methoxypropionate Methyl ethoxypropionate, ethyl methoxypropionate, ethyl ethoxypropionate, ethylene glycol monomethyl ether acetate, diethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monopropyl ether acetate, ethylene glycol monoisopropyl ether acetate, ethylene glycol mono Butyl ether acetate, ethylene glycol mono secondary butyl ether acetate, ethylene glycol mono isobutyl ether acetate, ethylene glycol mono tertiary butyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl Pyrether acetate, Propylene glycol monoisopropyl ether acetate, Propylene glycol monobutyl ether acetate, Propylene glycol mono secondary butyl ether acetate, Propylene glycol monoisobutyl ether acetate, Propylene glycol mono tertiary butyl ether acetate, Butylene glycol monomethyl ether acetate, Butylene glycol monoethyl Ether acetate, butylene glycol monopropyl ether acetate, butylene glycol monoisopropyl ether acetate, butylene glycol monobutyl ether acetate, butylene glycol mono sec-butyl ether acetate, butylene glycol monoisobutyl ether acetate, butylene glycol mono Examples include tertiary butyl ether acetate, methyl acetoacetate, ethyl acetoacetate, methyl oxobutanoate, ethyl oxobutanoate, γ-lactone, dimethyl malonate, dimethyl succinate, propylene glycol diacetate, and δ-lactone.

  Examples of the ether solvent include tetrahydrofuran, tetrahydropyran, morpholine, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, dipropylene glycol dimethyl ether, triethylene glycol dimethyl ether, dibutyl ether, diethyl ether, and dioxane.

  Examples of the aliphatic or alicyclic hydrocarbon solvents include pentane, hexane, cyclohexane, methylcyclohexane, dimethylcyclohexane, ethylcyclohexane, heptane, octane, decalin, solvent naphtha, turpentine oil, D-limonene, pinene, and minerals. Spirit, Swazol # 310 (Cosmo Matsuyama Oil Co., Ltd., Solvesso # 100 (Exxon Chemical Co., Ltd.)) and the like.

  Examples of the aromatic hydrocarbon solvent include benzene, toluene, ethylbenzene, xylene, mesitylene, diethylbenzene, cumene, isobutylbenzene, cymene, and tetralin.

  Examples of the hydrocarbon solvent having a cyano group include acetonitrile, 1-cyanopropane, 1-cyanobutane, 1-cyanohexane, cyanocyclohexane, cyanobenzene, 1,3-dicyanopropane, 1,4-dicyanobutane, , 6-dicyanohexane, 1,4-dicyanocyclohexane, 1,4-dicyanobenzene and the like.

  Examples of the halogenated hydrocarbon solvent include carbon tetrachloride, chloroform, dichloromethane, trichloroethylene, chlorobenzene, dichlorobenzene, and trichlorobenzene.

  Examples of the other organic solvents include N-methyl-2-pyrrolidone, dimethyl sulfoxide, dimethylformamide, aniline, triethylamine, pyridine, and carbon disulfide.

  Among these, preferable solvents include chloroform, dichloromethane, toluene, xylene, chlorobenzene, dichlorobenzene, trichlorobenzene and the like.

  When the above-described solvent is contained in the photoelectric conversion material of the present invention, the content is not particularly limited as long as it does not hinder the formation of a photoelectric conversion layer using the photoelectric conversion material. When 100 parts by weight, the total amount of (A) the compound represented by the general formula (1), (B) p-type organic semiconductor material and (C) n-type organic semiconductor material is 0.1 to 20 parts by weight. Is preferably selected from the range, more preferably 1 to 10 parts by weight, and particularly preferably 3 to 7 parts by weight.

<Photoelectric conversion layer>
Next, the photoelectric conversion layer of the present invention will be described. The photoelectric conversion layer of the present invention is obtained by forming the photoelectric conversion material of the present invention into a film. The film forming method is not particularly limited. For example, vapor deposition method, physical vapor deposition method (PVD), chemical vapor deposition method (CVD), atomic layer deposition method (ALD), atomic layer epitaxy method (ALE). ), Dry processes such as molecular beam epitaxy (MBE), vapor phase epitaxy (VPE), sputtering, plasma polymerization, etc .; dip coating, casting, air knife coating, curtain coating, roller coating, wire Forming a coating on a support by wet processes such as bar coating, gravure coating, spin coating, LB, offset printing, screen printing, flexographic printing, dispenser printing, ink jet, and extrusion coating The method of doing is mentioned.

  Although the film thickness of the said photoelectric converting layer is not specifically limited, Generally, it is preferable to set to about 5 nm-5 micrometers, and heat processing, such as annealing, may be performed.

  The photoelectric conversion layer is used for an element in which p-type and n-type organic semiconductor materials are mixed. In addition to the organic bulk heterojunction element which is a preferred embodiment, a super hierarchical nanostructure junction element, a hybrid heterojunction type, pi Used for the i layer and the like in an -n junction type element.

<Photoelectric conversion element and organic thin film solar cell>
The photoelectric conversion element of this invention is comprised similarly to a conventionally well-known photoelectric conversion element except having at least one photoelectric conversion layer of this invention. For example, taking FIG. 1A as an example, the support 1, the electrode 2, the charge transfer layer 3, the photoelectric conversion layer 4, and the electrode 5 are sequentially stacked. Further, a structure excluding the charge transfer layer 3 as shown in FIG. 1B or a structure further having a charge transfer layer 6 as shown in FIG. 1C may be used.

  In the photoelectric conversion element of the present invention, light needs to reach the photoelectric conversion layer 4 from the support 1. In order to allow irradiation light to reach the photoelectric conversion layer 4 from the support 1, the electrode 2 and the charge transfer layer 3, the support 1, the electrode 2 and the charge transfer layer 3 are formed of a light transmissive material, and the light transmittance Is preferably set to be 70% or more.

  As long as the support 1 can stably hold the electrode 2 on the surface, the support 1 is not limited by the material and thickness, but needs to have transparency. Therefore, the shape of the support may be plate or film. Transparency refers to the property of transmitting light in a predetermined wavelength region used in a photoelectric conversion element, for example, visible light region at a high rate. For the support 1, for example, glass, transparent polymer film (polyethylene terephthalate (PET), tetraacetyl cellulose (TAC), polycarbonate, polyethylene naphthalate, polyphenylene sulfide, polyester sulfone, syndiotactic polystyrene) or the like can be used. The photoelectric conversion element of the present invention is preferably formed on the surface of the support 1. However, when the electrode 2 itself has a certain degree of hardness and is self-supporting, the structure in which the electrode 2 also serves as the support 1. In this case, the support 1 may be omitted.

  In the present invention, the work functions of a pair of electrodes (electrode 2 and electrode 5) arranged opposite to each other may have a relative magnitude relationship with each other (that is, work functions are different from each other). Therefore, it is sufficient that the work function of the electrode 2 is relatively larger than that of the electrode 5. In this case, the work function difference between the two electrodes is preferably 0.5 V or more. In addition, when a buffer layer is provided between each electrode and the semiconductor layer and the compound of the buffer layer on the electrode and the electrode are chemically bonded, these restrictions may be relaxed.

  Examples of the electrodes 2 and 5 include noble metals such as gold, platinum, and silver, metals such as zinc oxide, indium oxide, tin oxide (NESA), tin-doped indium oxide (ITO), and fluorine-doped tin oxide (FTO). Oxide, lithium, lithium-indium alloy, sodium, sodium-potassium alloy, calcium, magnesium, magnesium-silver alloy, magnesium-indium alloy, indium, ruthenium, titanium, manganese, yttrium, aluminum, aluminum-lithium alloy, aluminum- In addition to calcium alloys, aluminum-magnesium alloys, chromium, graphite thin films, organic conductive compounds such as PEDOT-PSS can be used as appropriate. These electrode materials may be used alone or in combination. However, since the electrode 2 needs to have transparency, materials having transparency such as zinc oxide, NESA, ITO, FTO, and PEDOT-PSS are particularly used among the above electrode materials. The electrode 2 and the electrode 5 can be formed by using a dry process or a wet process using these electrode materials in the same manner as the photoelectric conversion layer 4. Further, it may be formed by firing by a sol-gel method or the like. Moreover, although the thickness of an electrode is based also on the material of the electrode substance to be used, both the electrode 2 and the electrode 5 are generally set to about 5-1000 nm, More preferably, about 10-500 nm.

The charge transfer layers 3 and 6 prevent the electrode material from entering and reacting with the photoelectric conversion layer, and prevent recombination of charges separated by the photoelectric conversion layer, thereby efficiently transferring the charge to the electrodes 2 and 5. There is a role such as letting. Examples of the material include charge transfer materials such as PEDOT: PSS, PEO, V ₂ O ₅ , zinc oxide, lithium fluoride, TiOx, and naphthalenetetracarboxylic acid anhydride. The charge transfer layer 3 needs to have transparency. When the photoelectric conversion layer 4 is a P3HT: PCBM bulk hetero type, PEDOT: PSS is often used for the charge transfer layer 3, and LiF is often used for the charge transfer layer 6. The charge transfer layers 3 and 6 can be formed using these charge transfer materials by a dry process method or a wet process method in the same manner as the photoelectric conversion layer 4. The thickness of the charge transfer layers 3 and 6 is generally set to 0.01 to 100 nm, more preferably about 0.1 to 50 nm.

  The photoelectric conversion element of this invention can be used for a photodiode, a photodetector, etc. other than the organic thin-film solar cell of this invention.

  Hereinafter, the present invention will be described in more detail with reference to synthesis examples, examples and comparative examples. However, the present invention is not limited by the following examples.

  Synthesis Examples 1 and 2 are synthesis examples of the novel compound of the present invention represented by the above general formula (1). In Examples 1 and 2, the photoelectric conversion material of the present invention was prepared using the novel compound obtained in the synthesis example, a photoelectric conversion layer and a photoelectric conversion element were prepared using the photoelectric conversion material, and the photoelectric conversion element Was evaluated. In Comparative Example 1, a comparative photoelectric conversion material was prepared in the same manner as in Example 1 except that the above-described novel compound was not used, and a comparative photoelectric conversion layer and a comparative photoelectric conversion element were prepared using the photoelectric conversion material. The photoelectric conversion element was evaluated.

[Synthesis Example 1] Compound No. 1 1
<Step 1> Production of 1,7-bis (2,2′-bithiophene) -4,4-bis (butoxymethyl) -1,6-heptadiyne (intermediate 1 shown in the following [Chemical 9]) 4, 4-bis (butoxymethyl) -1,6-heptadiyne (3.36 g, 12.7 mmol), 2-bromo-5- (2′-thienyl) thiophene (7.47 g, 30.5 mmol), Pd (PPh ₃ ) ₄ (352 mg, 0.305 mmol), CuI (116 mg, 0.61 mmol) and triethylamine (10 ml) were mixed in tetrahydrofuran (30 ml) and reacted at 45 ° C. with stirring for 12 hours. The resulting reaction solution was purified by silica gel column chromatography (hexane: ethyl acetate = 25: 1 mobile phase solvent) to give a colorless transparent liquid (6.3 g, isolated yield 83%). . It was confirmed by ¹ H-NMR, ¹³ C-NMR, and high-resolution mass spectrometry spectrum (HRMS) that it was the desired product.
¹ H-NMR (400 MHz, CDCl ₃ ): δ = 7.21 (dd, J = 1.2, 5.5 Hz, 2H), 7.15 (dd, J = 0.8, 3.6 Hz, 2H) , 6.99-7.03 (m, 6H), 3.45-3.49 (m, 8H), 2.65 (s, 4H), 1.52-1.62 (m, 4H), 1 .35-1.46 (m, 4H), 0.94 (t, J = 7.5 Hz, 6H)
¹³ C-NMR (100 MHz, CDCl ₃ ): δ = 137.6, 136.9, 131.9, 127.8, 124.7, 123.9, 123.2, 122.8, 92.3, 75 .6, 71.8, 71.3, 43.1, 31.7, 23.7, 19.4, 13.9
HRMS (EI): 592.1598 (calculated value); 592.1589 (measured value)

<Step 2> Compound No. Preparation of 1 A tetrahydrofuran solution of Cp ₂ ZrCl ₂ (729 mg, 2.5 mmol) was cooled to −78 ° C., n-BuLi (1.62 M / hexane solution, 5.0 mmol) was added dropwise, and the same temperature was maintained for 1 hour. Reacted. Next, the tetrahydrofuran solution of the intermediate 1 (1.25 mg, 2.1 mmol) obtained in Step 1 was mixed and reacted at 30 to 35 ° C. for 5 hours. Then, sulfur chloride (338 mg, 2.5 mmol) was added and reacted. The obtained reaction solution was purified by silica gel column chromatography (hexane: chloroform = 1: 1 mobile phase solvent) to give an orange powder (948 mg, isolated yield 72%). It was confirmed by ¹ H-NMR, ¹³ C-NMR, and high-resolution mass spectrometry spectrum (HRMS) that it was the desired product.
¹ H-NMR (400 MHz, CDCl ₃ ): δ = 7.22 (dd, J = 0.8, 5.1 Hz, 2H), 7.17 (dd, J = 1.2, 3.6 Hz, 2H) 7.09 (d, J = 4.0 Hz, 2H), 7.02 (dd, J = 3.6, 5.1 Hz, 2H), 6.99 (d, J = 3.6 Hz, 2H), 3.42-3.49 (m, 8H), 2.78 (s, 4H), 1.52-1.59 (m, 4H), 1.33-1.43 (m, 4H),. 92 (t, J = 7.1 Hz, 6H)
¹³ C-NMR (100 MHz, CDCl ₃ ): δ = 144.1, 137.2, 136.1, 136.0, 127.9, 125.0, 124.3, 124.2, 123.9, 123 .5, 73.9, 71.2, 55.4, 34.5, 31.6, 19.3, 13.9
HRMS (EI): 624.1318 (calculated value); 624.1301 (measured value)

[Synthesis Example 2] Compound No. 2 Production of 4 <Step 1> Production of 1- (2,2′-bithiophene) -4,4-bis (butoxymethyl) -1,6-heptadiyne (intermediate 2 shown in the following [Chemical Formula 10]) 4, 4-bis (butoxymethyl) -1,6-heptadiyne (3.36 g, 12.7 mmol), 2-bromo-5- (2′-thienyl) thiophene (3.11 g, 12.7 mmol), Pd (PPh ₃ ) ₄ (147 mg, 0.127 mmol), CuI (48 mg, 0.254 mmol) and triethylamine (5 ml) were mixed in tetrahydrofuran (40 ml) and reacted at room temperature with stirring for 12 hours. The obtained reaction solution was purified by silica gel column chromatography (hexane: ethyl acetate = 25: 1 mobile phase solvent) to obtain a colorless transparent liquid (3.7 g, isolated yield 68%). . It was confirmed by ¹ H-NMR, ¹³ C-NMR, and high-resolution mass spectrometry spectrum (HRMS) that it was the desired product.
¹ H-NMR (400 MHz, CDCl ₃ ): δ = 7.21 (dd, J = 0.8, 5.1 Hz, 1H), 7.15 (dd, J = 0.8, 3.9 Hz, 1H) , 6.9-7.03 (m, 3H), 3.42-3.47 (m, 8H), 2.62 (s, 2H), 2.42 (d, J = 2.8 Hz, 1H) 2.00 (t, J = 2.8 Hz, 1H), 1.52-1.58 (m, 4H), 1.36-1.43 (m, 4H), 0.93 (t, J = 7.5Hz, 6H)
¹³ C-NMR (100 MHz, CDCl ₃ ): δ = 137.5, 136.9, 131.8, 127.8, 124.7, 123.9, 123.2, 122.8, 92.3, 81 .1, 77.2, 75.5, 71.5, 71.2, 70.3, 42.4, 31.7, 23.3, 22.2, 19.3
HRMS (EI): 428.1843 (calculated value); 428.1843 (measured value)

<Step 2> Production of 1- (2,2′-bithiophene) -4,4-bis (butoxymethyl) -1,6-heptadiyne (Intermediate 3 shown in the following [Chemical Formula 11]) Intermediate 2 (1.89 g, 4.4 mmol), 5,5′-dibromo- (2,2′-bithiophene) (583 mg, 1.8 mmol), Pd (PPh ₃ ) ₄ (42 mg, 0.036 mmol) , CuI (14 mg, 0.072 mmol) and triethylamine (1.7 ml) were mixed in tetrahydrofuran (10 ml) and reacted at 45 ° C. with stirring for 12 hours. The resulting reaction solution was purified by silica gel column chromatography (hexane: ethyl acetate = 15: 1 mobile phase solvent) to give a pale yellow liquid (1.56 g, isolated yield 85%). It was confirmed by ¹ H-NMR, ¹³ C-NMR, and high-resolution mass spectrometry spectrum (HRMS) that it was the desired product.
¹ H-NMR (400 MHz, CDCl ₃ ): δ = 7.22 (dd, J = 0.8, 4.8 Hz, 2H), 7.16 (dd, J = 0.8, 3.6 Hz, 2H) 7.00-7.05 (m, 8H), 6.97-6.99 (dd, J = 0.8, 3.6 Hz, 2H), 3.46-3.51 (m, 16H), 2.68 (s, 8H), 1.55-1.62 (m, 8H), 1.39-1.47 (m, 8H), 0.96 (dt, J = 7.2, 7.6 Hz) , 12H)
¹³ C-NMR (100 MHz, CDCl ₃ ): δ = 137.6, 136.9, 136.8, 131.9, 131.8, 127.8, 124.6, 123.9, 123.4, 123 .2, 123.1, 122.7, 92.7, 92.3, 75.63, 75.56, 71.8, 71.3, 43.0, 31.7, 23.7, 19.4 , 13.9
HRMS (EI): 1018.3285 (calculated value); 1018.3280 (measured value)

<Step 3> Compound No. Preparation of 4 A solution of Cp ₂ ZrCl ₂ (371 mg, 1.27 mmol) in tetrahydrofuran was cooled to −78 ° C., n-BuLi (1.62 M / hexane solution, 2.54 mmol) was added dropwise, and the same temperature was maintained for 1 hour. Reacted. Next, a tetrahydrofuran solution of the intermediate 3 (507 mg, 0.49 mmol) obtained in Step 2 was mixed and reacted at 30 to 35 ° C. for 5 hours. Then, sulfur chloride (199 mg, 1.47 mmol) was added and reacted. The obtained reaction solution was purified by silica gel column chromatography (hexane: chloroform = 1: 2 mobile phase solvent) to obtain a red powder (248 mg, isolated yield 46%). It was confirmed by ¹ H-NMR, ¹³ C-NMR, and high-resolution mass spectrometry spectrum (HRMS) that it was the desired product.
¹ H-NMR (400 MHz, CDCl ₃ ): δ = 7.22 (dd, J = 0.8, 5.1 Hz, 2H), 7.17 (dd, J = 1.2, 3.6 Hz, 2H) 7.08 (d, J = 4.0 Hz, 4H), 7.02 (dd, J = 3.6, 5.1 Hz, 2H), 7.00 (d, J = 4.0 Hz, 4H), 3.42-3.49 (m, 16H), 2.78 (s, 8H), 1.52-1.59 (m, 8H), 1.33-1.43 (m, 8H),. 92 (t, J = 7.1 Hz, 12H)
¹³ C-NMR (100 MHz, CDCl ₃ ): δ = 144.2, 144.1, 137.2, 136.1, 136.05, 136.03, 135.9, 127.9, 125.09, 125 .06, 124.3, 124.2, 124.0, 124.0, 123.98, 123.91, 123.5, 73.9, 71.2, 55.4, 34.5, 31.6 , 19.3, 13.9
HRMS (EI): 1082.2726 (calculated value); 1082.2738 (measured value)

[Example 1]
A photoelectric conversion element having the layer structure shown in FIG. 1C was produced by the following procedure.
A glass substrate (support 1) having an ITO film of 150 nm formed as the electrode 2 was subjected to IPA boiling cleaning and UV-ozone cleaning, and then PEDOT: PSS (3,4-ethylenedioxythiophene: polystyrene sulfone) on the electrode 2. Acid) was formed by a 20 nm spin coating method and dried under reduced pressure at 100 ° C. for 10 minutes to form a charge transfer layer 3. Separately from this, 2 mL of 1,2-dichlorobenzene was added to (A) compound No. 1 as a compound represented by the above general formula (1). 1 was dissolved in 5 mg, (B) 50 mg of P3HT as a p-type organic semiconductor, and (C) 50 mg of PCBM as an n-type organic semiconductor were dissolved to prepare a photoelectric conversion material of Example 1. The prepared photoelectric conversion material was formed on the charge transfer layer 3 by a spin coating method and dried under reduced pressure at 100 ° C. for 30 minutes to obtain a photoelectric conversion layer 4. On the photoelectric conversion layer 4 which is the organic thin film layer thus obtained, LiF 0.5 nm (charge transfer layer 6) and aluminum 100 nm (electrode 5) were sequentially deposited by vacuum deposition using a metal mask. A photoelectric conversion element was prepared.
The photoelectric conversion element thus obtained was irradiated with pseudo sunlight having an air mass of 1.5 G and 100 mW / cm ² from the ITO electrode side, and the photoelectric conversion characteristics (efficiency (%)) were measured. The results are shown in [Table 1].

[Example 2]
In the production of the photoelectric conversion element of Example 1, the photoelectric conversion of Example 2 was performed in the same manner as in Example 1 except that the components (A) to (C) and the composition ratio were changed as shown in [Table 1]. A conversion element was produced. Moreover, the photoelectric conversion characteristic (efficiency (%)) of the photoelectric conversion element of Example 2 was measured by the same operation as that of Example 1. The results are shown in [Table 1].

[Comparative Example 1]
In the production of the photoelectric conversion element of Example 1, the photoelectric conversion element of Comparative Example 1 was produced in the same manner as in Example 1 except that the component (A) was not used, and the same operation as in Example 1 was performed. The photoelectric conversion characteristics (efficiency (%)) of the photoelectric conversion element of Comparative Example 1 were measured. The results are shown in [Table 1].

From the above results, when the compound of the present invention represented by the general formula (1) as the component (A) is added to the (B) p-type organic semiconductor material and the (C) n-type organic semiconductor material, the photoelectric conversion efficiency is increased. It was confirmed that it improved.
Therefore, the photoelectric conversion material to which the novel compound of the present invention represented by the general formula (1) is added is useful for a photoelectric conversion element.

DESCRIPTION OF SYMBOLS 1 Support body 2 Electrode 3 Charge transfer layer 4 Photoelectric conversion layer 5 Electrode 6 Charge transfer layer

Claims (6)

The compound represented by the following general formula (1) -1 .

( Wherein A ¹ represents bithiophenyl , A ² represents divalent thiophene, benzothiophene, bithiophene or terthiophene, or divalent phenylene , ring B ¹ ′ represents cyclopentyl , and n represents 0 or 1 was Table, X ¹ represents a carbon atom, R ¹ and R ² are each independently, -O -, - COO -, - OCO -, - CO- or carbon interrupted by -S- Represents an aliphatic hydrocarbon group having 1 to 5 atoms. (A) A photoelectric conversion material comprising a compound represented by the following general formula (1) -1 ; (B) a p-type organic semiconductor material; and (C) an n-type organic semiconductor material.

( Wherein A ¹ represents bithiophenyl , A ² represents divalent thiophene, benzothiophene, bithiophene or terthiophene, or divalent phenylene , ring B ¹ ′ represents cyclopentyl , and n represents 0 or 1 was Table, X ¹ represents a carbon atom, R ¹ and R ² are each independently, -O -, - COO -, - OCO -, - CO- or carbon interrupted by -S- Represents an aliphatic hydrocarbon group having 1 to 5 atoms. The photoelectric conversion material according to claim 2 , wherein the (B) p-type organic semiconductor material is poly (3-hexylthiophene), and the (C) n-type organic semiconductor material is a fullerene derivative. A photoelectric conversion layer obtained by forming a film of the photoelectric conversion material according to claim 2 . A photoelectric conversion element comprising the photoelectric conversion layer according to claim 4 . An organic thin-film solar cell comprising the photoelectric conversion element according to claim 5 .

Images