JP5658937B2 - Indenoperylene compound and organic thin film solar cell using the same - Google Patents

Description

  The present invention relates to a novel indenoperylene derivative, an organic thin film solar cell material comprising the same, and an organic thin film solar cell using the same.

An organic thin film solar cell is a device that exhibits an electrical output with respect to an optical input, and a device that exhibits a response opposite to that of an electroluminescence (EL) element that exhibits an optical output with respect to the electrical input. Organic thin-film solar cells, which are classified as one of them, have attracted much attention in recent years as a source of clean energy against the background of fossil fuel depletion and global warming, and research and development are actively underway. .
Conventionally, silicon solar cells typified by single crystal Si, polycrystal Si, amorphous Si, etc. have been put into practical use. The demand for next generation solar cells is increasing. Against this background, organic solar cells are attracting much attention as next-generation solar cells next to silicon-based solar cells because they are inexpensive and have no fear of shortage of raw materials.

An organic solar cell basically includes an n layer that transports electrons and a p layer that transports holes.
An n-layer that adsorbs a single molecule of a sensitizing dye such as ruthenium dye on the surface of an inorganic semiconductor such as titania and uses an electrolyte solution as a p-layer is called a dye-sensitized solar cell (so-called Gretzel cell), which is photoelectrically converted. It has been energetically studied since 1991 because of its high efficiency (hereinafter sometimes referred to simply as “conversion efficiency”). However, since it uses a solution, it has drawbacks such as liquid leakage when used for a long time. It was.
In order to overcome these drawbacks, research has been recently conducted to find an all-solid-state dye-sensitized solar cell by solidifying the electrolyte solution, but it is difficult to immerse organic matter into the pores of porous titania. At present, a cell having a high degree of reproducibility and high conversion efficiency has not been completed.

On the other hand, organic thin-film solar cells consisting of organic thin films in both the n-layer and p-layer are all solid, so they have no drawbacks such as liquid leakage, are easy to manufacture, and do not use ruthenium, which is a rare metal. Attracted attention and researched energetically.
Organic thin-film solar cells have been researched with single-layer films using merocyanine dyes, etc., but it has been found that conversion efficiency can be improved by using p-layer / n-layer multilayer films. Organic thin-film solar cells in which a multilayer film is arranged have become mainstream. The materials used at this time were copper phthalocyanine (CuPc) for the p layer and peryleneimides (PTCBI) for the n layer.
Subsequently, it was found that the conversion efficiency is improved by inserting an i layer (a mixed layer of p material and n material) between the p layer and the n layer. However, the materials used at this time were still phthalocyanines and peryleneimides. Further Thereafter, further conversion efficiency stack cell configuration in the p / i / n layers be stacked several layers have been found to improve the material system at that time was phthalocyanines and fullerene C _60.

On the other hand, in an organic thin film solar cell using a polymer, a conductive polymer is used as a p material (a material used for a p layer), and a C ₆₀ derivative is used as an n material (a material used for an n layer). Research on so-called bulk heterostructures has been mainly conducted, in which micro-layer separation of the p layer and n layer is induced by mixing and heat treatment to increase the heterointerface and improve the conversion efficiency. Here the material system used primarily, soluble polythiophene derivative called P3HT as p material was soluble C ₆₀ derivatives referred to as PCBM as an n material.

Thus, in the organic thin film solar cell, the conversion efficiency has been improved by optimizing the cell configuration and the morphology of the p material and the n material, but the material system used has not made much progress since the early days, and phthalocyanines, perylene imide _{acids, C 60} compounds have been used. Therefore, development of a new material system to replace these has been eagerly desired.

  In general, the operation process of an organic solar cell consists of (1) light absorption and exciton generation, (2) exciton diffusion, (3) charge separation, (4) charge transfer, and (5) electromotive force generation. In general, many organic substances do not exhibit many absorption characteristics that match the solar spectrum, and thus high conversion efficiency cannot often be achieved.

  As a means for improving the performance of any of the above elementary processes and improving the conversion efficiency, a new material system has been studied.

  For example, Patent Document 1 discloses an organic photoelectric conversion element using a perifuranthene derivative. However, since it has a structure having a benzofluoranthene skeleton on both sides of the perylene skeleton, the molecular weight is large, and when an organic thin film solar cell is produced by using a vapor deposition method, sublimation is difficult. May cause.

  Patent Document 2 discloses an organic thin film solar cell using a compound in which an aromatic amine moiety is introduced into an acenaphthofluoranthene skeleton. Although high conversion efficiency is disclosed in the embodiment, further improvement in efficiency is required.

JP 2008-135540 A JP 2009-132673 A

  An object of the present invention is to provide an indenoperylene derivative useful as a material for an organic thin film solar cell, and particularly to provide a compound exhibiting high photoelectric conversion efficiency when used in an organic thin film solar cell. is there.

（式（１）中、Ｒ_１〜Ｒ_１６はそれぞれ独立に、水素原子、置換もしくは無置換の炭素数１〜４０のアルキル基、置換もしくは無置換の炭素数２〜４０のアルケニル基、置換もしくは無置換の炭素数２〜４０のアルキニル基、置換もしくは無置換の環形成炭素数６〜４０のアリール基、置換もしくは無置換の環形成原子数５〜４０のヘテロアリール基、置換もしくは無置換の炭素数１〜４０のアルコキシ基、置換もしくは無置換の環形成炭素数６〜４０のアリールオキシ基、又は式（２）のアミノ基であり、Ｒ_１〜Ｒ_１６のうち少なくとも１つは式（２）のアミノ基である。

（式中、Ｒ_ａ，Ｒ_ｂは置換もしくは無置換の環形成炭素数６〜４０のアリール基又は置換もしくは無置換の炭素数１〜４０のアルキル基である。））
２．式（３）で表される１に記載のインデノペリレン誘導体。

（式（３）中、Ｒ_１〜Ｒ_１５及びＲ_ａ，Ｒ_ｂは式（１），（２）と同様である。）
３．式（４）で表される２に記載のインデノペリレン誘導体。

（式中、Ｒ_１０１〜Ｒ_１３３はそれぞれ独立に、水素原子、置換もしくは無置換の炭素数１〜４０のアルキル基、置換もしくは無置換の環形成炭素数６〜４０のアリール基、置換もしくは無置換の環形成原子数５〜４０のヘテロアリール基、又は置換もしくは無置換の炭素数１〜４０のアルコキシ基である。）
４．１〜３のいずれかに記載のインデノペリレン誘導体からなる有機薄膜太陽電池材料。
５．１〜３のいずれかに記載のインデノペリレン誘導体を含有する有機薄膜太陽電池。
６．少なくともｐ層を有する有機薄膜太陽電池において、ｐ層に１〜３のいずれかに記載のインデノペリレン誘導体を用いる有機薄膜太陽電池。
７．少なくともｐ層とｎ層を有する有機薄膜太陽電池において、ｎ層にフラーレン誘導体を用い、ｐ層に１〜３のいずれかに記載のインデノペリレン誘導体を用いる有機薄膜太陽電池。 According to the present invention, the following indenoperylene derivatives and the like are provided.
1. An indenoperylene derivative represented by the formula (1).

(In formula (1), R _{1 to} R ₁₆ are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 40 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 40 carbon atoms, a substituted or An unsubstituted alkynyl group having 2 to 40 carbon atoms, a substituted or unsubstituted aryl group having 6 to 40 ring carbon atoms, a substituted or unsubstituted heteroaryl group having 5 to 40 ring atoms, substituted or unsubstituted An alkoxy group having 1 to 40 carbon atoms, a substituted or unsubstituted aryloxy group having 6 to 40 ring carbon atoms, or an amino group of the formula (2), and at least one of R _{1 to} R ₁₆ is represented by the formula ( 2) amino group.

(In the formula, R _a and R _b are a substituted or unsubstituted aryl group having 6 to 40 ring carbon atoms or a substituted or unsubstituted alkyl group having 1 to 40 carbon atoms.)
2. 2. The indenoperylene derivative represented by formula (3).

(In formula (3), R _{1 to} R ₁₅ and R _a and R _b are the same as in formulas (1) and (2).)
3. The indenoperylene derivative according to 2, which is represented by formula (4).

(Wherein R _{101 to} R ₁₃₃ each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 40 carbon atoms, a substituted or unsubstituted aryl group having 6 to 40 ring carbon atoms, substituted or unsubstituted It is a substituted heteroaryl group having 5 to 40 ring atoms or a substituted or unsubstituted alkoxy group having 1 to 40 carbon atoms.)
The organic thin-film solar cell material which consists of an indenoperylene derivative in any one of 4.1-3.
The organic thin-film solar cell containing the indenoperylene derivative in any one of 5.1-3.
6). An organic thin-film solar cell having at least a p-layer, wherein the indenoperylene derivative according to any one of 1 to 3 is used for the p-layer.
7). An organic thin-film solar cell having at least a p-layer and an n-layer, wherein a fullerene derivative is used for the n-layer and the indenoperylene derivative according to any one of 1 to 3 is used for the p-layer.

  ADVANTAGE OF THE INVENTION According to this invention, the compound which shows a highly efficient photoelectric conversion efficiency when it uses for an organic thin-film solar cell, especially an indenoperylene derivative useful as an organic thin-film solar cell material can be provided.

式（１）中、Ｒ_１〜Ｒ_１６はそれぞれ独立に、水素原子、置換もしくは無置換の炭素数１〜４０のアルキル基、置換もしくは無置換の炭素数２〜４０のアルケニル基、置換もしくは無置換の炭素数２〜４０のアルキニル基、置換もしくは無置換の環形成炭素数６〜４０のアリール基、置換もしくは無置換の環形成原子数５〜４０のヘテロアリール基、置換もしくは無置換の炭素数１〜４０のアルコキシ基、置換もしくは無置換の環形成炭素数６〜４０のアリールオキシ基、又は式（２）のアミノ基であり、Ｒ_１〜Ｒ_１６のうち少なくとも１つは式（２）のアミノ基である。

式（２）中、Ｒ_ａ，Ｒ_ｂは置換もしくは無置換の環形成炭素数６〜４０のアリール基又は置換もしくは無置換の炭素数１〜４０のアルキル基である。 The indenoperylene derivative of the present invention is represented by the formula (1).

In formula (1), R _{1 to} R ₁₆ are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 40 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 40 carbon atoms, substituted or unsubstituted. Substituted alkynyl group having 2 to 40 carbon atoms, substituted or unsubstituted aryl group having 6 to 40 ring carbon atoms, substituted or unsubstituted heteroaryl group having 5 to 40 ring atoms, substituted or unsubstituted carbon An alkoxy group having 1 to 40 carbon atoms, a substituted or unsubstituted aryloxy group having 6 to 40 ring carbon atoms, or an amino group represented by formula (2), wherein at least one of R _{1 to} R ₁₆ is represented by formula (2 ) Amino group.

In formula (2), R _a and R _b are a substituted or unsubstituted aryl group having 6 to 40 ring carbon atoms or a substituted or unsubstituted alkyl group having 1 to 40 carbon atoms.

The compound of the formula (1) has an indenoperylene structure and has a benzofluoranthene skeleton on only one of the perylene skeletons, so that the increase in molecular weight is suppressed.
When this compound is used as a p-material for an organic thin film solar cell, high conversion efficiency is obtained, and when an organic thin film solar cell is produced by a vapor deposition method, sublimation is easy, resulting in difficulty in sublimation. A decrease in productivity can be avoided.

  In the compound of the formula (1), the reason why the structure of the formula (2) is essential is that hole transportability can be obtained by introducing an amino group having an excess electron (for example, a diarylamino group or a dialkylamino group). This is to improve the conversion efficiency when used as a member of an organic thin film solar cell.

In Formula (1), one or more of R ₃ , R ₄ , R ₁₁ , and R ₁₂ are the amino groups of Formula (2), and R ₁ , R ₂ , R _{5 to} R ₁₀ , and R _{13 to} R ₁₆ are A group other than formula (2) or a hydrogen atom is preferred from the viewpoint of ease of compound production.
Moreover, when using the compound of Formula (1) as a member of an organic thin-film solar cell, it is preferable at the point which carries out a charge transfer stably that the number of the amino groups of Formula (2) is 1. Therefore, the compounds of formula (3) and formula (4) are preferred.

R _a and R _{b in} the formula (2) are a substituted or unsubstituted aryl group having 6 to 40 ring carbon atoms or a substituted or unsubstituted alkyl group having 1 to 40 carbon atoms. is the same as the exemplary aryl group or alkyl group of R ₁ to R _16. Since radical cations (holes) exist stably, an aryl group is preferred from the viewpoint of obtaining stable charge transfer. As the aryl group, a phenyl group, a naphthyl group, a biphenyl group and the like are preferable.

式（３）において、Ｒ_１〜Ｒ_１５及びＲ_ａ，Ｒ_ｂは式（１），（２）と同様である。 The indenoperylene derivative of the present invention is preferably represented by the formula (3).

In the formula (3), R _{1 to} R ₁₅ and R _a and R _b are the same as those in the formulas (1) and (2).

The compound of the formula (3) is a compound in which R ₁₁ or R ₁₂ in the formula (1) is the formula (2). Since R ₁₁ and R _{12 in} formula (1) are sites where amino groups can be easily introduced, from the viewpoint of productivity, the compound having one amino group is preferably a compound of formula (3).

The indenoperylene derivative of the present invention is preferably represented by the formula (4).
A structure in which R ₁ , R ₆ , R _a and R _b in formula (3) are phenyl groups which may have a substituent is formula (4). It is similar to mTPD (a hole transport material for organic EL elements) in that it has a diphenylamino group and has four phenyl groups. For this reason, it is considered that higher charge transfer is obtained, and as a result, it is considered that high conversion efficiency as shown in the examples can be obtained.

式中、Ｒ_１０１〜Ｒ_１３３はそれぞれ独立に、水素原子、置換もしくは無置換の炭素数１〜４０のアルキル基、置換もしくは無置換の環形成炭素数６〜４０のアリール基、置換もしくは無置換の環形成原子数５〜４０のヘテロアリール基、又は置換もしくは無置換の炭素数１〜４０のアルコキシ基である。具体例は、下記のＲ_１〜Ｒ_１６の例示と同様である。

In the formula, R _{101 to} R ₁₃₃ are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 40 carbon atoms, a substituted or unsubstituted aryl group having 6 to 40 ring carbon atoms, substituted or unsubstituted. A heteroaryl group having 5 to 40 ring atoms, or a substituted or unsubstituted alkoxy group having 1 to 40 carbon atoms. Specific examples are the same as the examples of R _{1 to} R ₁₆ below.

  The four phenyl groups represented by the formula (4) may have a substituent, but are preferably unsubstituted. However, a bulky alkyl substituent such as a t-butyl group may contribute to an improvement in conversion efficiency.

The substituted or unsubstituted alkyl group having 1 to 40 carbon atoms of R _{1 to} R ₁₆ may be linear, branched or cyclic. Specifically, for example, methyl group, ethyl group, 1-propyl group, 2-propyl group, 1-butyl group, 2-butyl group, sec-butyl group, tert-butyl group, various pentyl groups, various Hexyl group, various octyl groups, various decyl groups, various dodecyls, 2-ethylhexyl group, 3,7-dimethyloctyl group, cyclopropyl group, cyclopentyl group, cyclohexyl group, 1-adamantyl group, 2-adamantyl group, Examples include a norbornyl group, a trifluoromethyl group, a trichloromethyl group, a benzyl group, an α, α-dimethylbenzyl group, a 2-phenylethyl group, and a 1-phenylethyl group. Of these, a methyl group, an ethyl group, a 1-propyl group, a 2-propyl group, a tert-butyl group, and a cyclohexyl group are preferable from the viewpoint of availability of raw materials.
Examples of the substituent of the alkyl group include a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, an aryl group such as a phenyl group, and a methyl group as a substituent further bonded to the aryl group. , An alkyl group having 1 to 5 carbon atoms such as an ethyl group and a propyl group.

The substituted or unsubstituted alkenyl group having 2 to 40 carbon atoms of R _{1 to} R ₁₆ may be linear, branched or cyclic. Specifically, for example, vinyl group, propenyl group, butenyl group, oleyl group, eicosapentaenyl group, docosahexaenyl group, styryl group, 2,2-diphenylvinyl group, 1,2,2-triphenylvinyl Group, 2-phenyl-2-propenyl group and the like. Among these, a vinyl group, a styryl group, and a 2,2-diphenylvinyl group are preferable from the viewpoint of availability of raw materials.
Examples of the substituent for the alkenyl group include halogen atoms such as fluorine atom, chlorine atom, bromine atom and iodine atom, and aryl groups such as phenyl group.

The substituted or unsubstituted alkynyl group having 2 to 40 carbon atoms of R _{1 to} R ₁₆ may be linear, branched or cyclic. Specific examples include ethenyl group, propynyl group, 2-phenylethenyl group and the like.
Examples of the substituent for the alkenyl group include halogen atoms such as fluorine atom, chlorine atom, bromine atom and iodine atom, and aryl groups such as phenyl group.

Specific examples of the substituted or unsubstituted aryl group having 6 to 40 ring carbon atoms of R _{1 to} R ₁₆ include, for example, a phenyl group, a 2-tolyl group, a 4-tolyl group, and a 4-trifluoromethylphenyl group. 4-methoxyphenyl group, 4-cyanophenyl group, 2-biphenylyl group, 3-biphenylyl group, 4-biphenylyl group, terphenylyl group, 3,5-diphenylphenyl group, 3,4-diphenylphenyl group, pentaphenylphenyl Group, 4- (2,2-diphenylvinyl) phenyl group, 4- (1,2,2-triphenylvinyl) phenyl group, fluorenyl group, 1-naphthyl group, 2-naphthyl group, 9-anthryl group, 2 -Anthryl group, 9-phenanthryl group, 1-pyrenyl group, chrycenyl group, naphthacenyl group, coronyl group and the like can be mentioned. Of these, a phenyl group, a 4-biphenylyl group, a 1-naphthyl group, a 2-naphthyl group, a 9-phenanthryl group and the like are preferable from the viewpoint of availability of raw materials.
Examples of the substituent for the aryl group include halogen atoms such as fluorine atom, chlorine atom, bromine atom and iodine atom, alkoxy groups having 1 to 5 carbon atoms such as methoxy group, ethoxy group and propoxy group, cyano group and phenyl group. And a vinyl group substituted with an aryl group such as a group.

Specific examples of the substituted or unsubstituted heteroaryl group having 5 to 40 ring atoms of R _{1 to} R ₁₆ include, for example, furan, thiophene, pyrrole, imidazole, benzimidazole, pyrazole, benzpyrazole, triazole, oxa Examples include heteroaryl groups based on diazole, pyridine, pyrazine, triazine, quinoline, benzofuran, dibenzofuran, benzothiophene, dibenzothiophene, or carbazole. Of these, heteroaryl groups based on furan, thiophene, pyridine, carbazole, and the like are preferable from the viewpoint of availability of raw materials.
When the heteroaryl group is based on a nitrogen-containing azole heterocycle, the bonding position with the indenoperylene skeleton of the general formula (1) may be carbon or nitrogen.

The substituted or unsubstituted alkoxy group having 1 to 40 carbon atoms of R _{1 to} R ₁₆ may be linear, branched or cyclic, and specific examples thereof include, for example, methoxy group, ethoxy Group, 1-propyloxy group, 2-propyloxy group, 1-butyloxy group, 2-butyloxy group, sec-butyloxy group, tert-butyloxy group, various pentyloxy groups, various hexyloxy groups, various octyloxy groups Group, various decyloxy groups, various dodecyloxy groups, 2-ethylhexyloxy group, 3,7-dimethyloctyloxy, cyclopropyloxy, cyclopentyloxy, cyclohexyloxy, 1-adamantyloxy group, 2-adamantyloxy group, nor Bornyloxy group, trifluoromethoxy group, benzyloxy group, α, α -A dimethyl benzyloxy group, 2-phenylethoxy group, 1-phenylethoxy etc. are mentioned. Of these, a methoxy group, an ethoxy group, a tert-butyloxy group, and the like are preferable from the viewpoint of availability of raw materials. Examples of the substituent of the alkoxy group include a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, an aryl group such as a phenyl group, and a methyl group as a substituent further bonded to the aryl group. , An alkyl group having 1 to 5 carbon atoms such as an ethyl group and a propyl group.

Specific examples of the substituted or unsubstituted aryloxy group having 6 to 40 ring carbon atoms of R _{1 to} R ₁₆ include a substituent in which the aryl group is bonded through oxygen. Of these, a phenoxy group, a naphthoxy group, a phenanthryloxy group, and the like are preferable from the viewpoint of availability of raw materials.

Examples of the indenoperylene derivative of the present invention include the following compounds.

  The indenoperylene derivative of the present invention can be suitably used as an organic thin film solar cell material, and can be particularly suitably used as a p-layer material. The reason for this is that the long wavelength absorption based on the perylene skeleton enhances the compatibility with the sunlight spectrum, making it easier to generate photoexcitons, and the holes generated by the charge separation of the excitons are the indenoperylene derivatives. It can be considered that the amine structure is easily transported to the electrode due to the contribution of the amine structure.

The organic thin film solar cell of the present invention contains the above-mentioned indenoperylene derivative (organic thin film solar cell material) and exhibits high-efficiency conversion characteristics.
The member of the organic thin film solar cell of the present invention may be formed of the organic thin film solar cell material of the present invention alone, or may be formed of a mixture of the organic thin film solar cell material of the present invention and other components. .

The cell structure of the organic thin film solar cell of the present invention is not particularly limited as long as a layer containing the indenoperylene derivative of the present invention is provided between a pair of electrodes. Specifically, for example, a structure having the following configuration on a stable insulating substrate can be given.
(1) Lower electrode / p layer / n layer / upper electrode (2) Lower electrode / p layer / i layer (or mixed layer of p material and n material) / n layer / upper electrode (3) Lower electrode / p material And a mixed layer of n material / upper electrode and a structure in which the p layer and the n layer having the constitutions (1) and (2) described above are replaced with each other.
Moreover, you may provide a buffer layer between an electrode and an organic layer as needed. For example, the structure which has the following structure as a specific example is mentioned.
(4) Lower electrode / buffer layer / p layer / n layer / upper electrode (5) Lower electrode / p layer / n layer / buffer layer / upper electrode (6) Lower electrode / buffer layer / p layer / n layer / buffer Layer / Top electrode

  The organic thin film solar cell material of the present invention can be used for a p layer or an i layer (a mixed layer of a p material and an n material). Further, by introducing an electron-withdrawing group such as a fluorine atom, it can be used for the n layer and the buffer layer.

  In the organic thin-film solar cell of the present invention, any material constituting the battery may contain the material of the present invention. Moreover, the member containing the material of this invention may contain the other component collectively. About the member and mixed material which do not contain the material of this invention, the well-known member and material used with an organic thin film solar cell can be used. Hereinafter, each component will be described.

1. Lower electrode, upper electrode The material of the lower electrode and the upper electrode is not particularly limited, and a known conductive material can be used. For example, a metal such as tin-doped indium oxide (ITO), gold (Au), osmium (Os), palladium (Pd) can be used as the electrode connected to the p layer, and silver as the electrode connected to the n layer. Metals such as (Ag), aluminum (Al), indium (In), calcium (Ca), platinum (Pt) lithium (Li) and the like, and binary metal systems such as Mg: Ag, Mg: In and Al: Li, Can use the electrode exemplified material connected to the p layer.
In order to obtain highly efficient photoelectric conversion characteristics, for example, when the organic thin film solar cell is a solar cell, it is desirable that at least one surface of the solar cell is sufficiently transparent in the solar spectrum. The transparent electrode is formed using a known conductive material so as to ensure predetermined translucency by a method such as vapor deposition or sputtering. The light transmittance of the electrode on the light receiving surface is preferably 10% or more. In a preferred configuration of the pair of electrode configurations, one of the electrode portions includes a metal having a high work function, and the other includes a metal having a low work function.

2. Organic compound layer One of a p layer, a mixed layer of p material and n material, or an n layer. When the material of the present invention is used for the organic compound layer, specifically, the lower electrode / the single layer of the material of the present invention / the upper electrode, the lower electrode / the material of the present invention, and the n layer material or p layer described later. Examples include a mixed layer / top electrode material.

3. p layer, n layer, i layer When the material of the present invention is used for the p layer, the n layer is not particularly limited, but a compound having a function as an electron acceptor is preferable. For example, in the case of organic compounds, fullerene derivatives such as C ₆₀ , C ₇₀ , PCBM, and PC ₇₀ BM, carbon nanotubes, perylene derivatives, polycyclic quinones, quinacridones, etc., such as CN-poly (phenylene-vinylene), MEH —CN—PPV, —CN group or CF ₃ group-containing polymers, —CF ₃ substituted polymers, poly (fluorene) derivatives, and the like can be mentioned. A material having high electron mobility is preferred. Further, a material having a small electron affinity is preferable. Thus, a sufficient open-circuit voltage can be realized by combining materials having a small electron affinity as the n layer.

Moreover, if it is an inorganic compound, the inorganic semiconductor compound of an n-type characteristic can be mentioned. Specifically, doped semiconductors and compound semiconductors such as n-Si, GaAs, CdS, PbS, CdSe, InP, Nb ₂ O ₅ , WO ₃ , Fe ₂ O ₃ , titanium dioxide (TiO ₂ ), monoxide Examples include titanium oxide such as titanium (TiO) and dititanium trioxide (Ti ₂ O ₃ ), and conductive oxides such as zinc oxide (ZnO) and tin oxide (SnO ₂ ). You may use combining more than a seed. Preference is given to using titanium oxide, particularly preferably titanium dioxide.

  When the material of the present invention is used for the n layer, the p layer is not particularly limited, but a compound having a function as a hole acceptor is preferable. For example, in the case of an organic compound, N, N′-bis (3-tolyl) -N, N′-diphenylbenzidine (mTPD), N, N′-dinaphthyl-N, N′-diphenylbenzidine (NPD), 4, Amine compounds represented by 4 ′, 4 ″ -tris (phenyl-3-tolylamino) triphenylamine (MTDATA), etc., phthalocyanine (Pc), copper phthalocyanine (CuPc), zinc phthalocyanine (ZnPc), titanyl phthalocyanine (TiOPc) ), Phthalocyanines such as octaethylporphyrin (OEP), platinum octaethylporphyrin (PtOEP), zinc tetraphenylporphyrin (ZnTPP) and the like, and polymer compounds such as polyhexylthiophene (P3HT), Methoxyethylhexyloxyphe Vinylene (MEHPPV) main chain type conjugated polymers such as side chain type polymers such as represented by polyvinyl carbazole, and the like.

  When the material of the present invention is used for the i layer, the i layer may be formed by mixing with the p layer compound or the n layer compound, but the material of the present invention can also be used alone as the i layer. In this case, any of the above exemplary compounds can be used for the p layer or the n layer.

4). Buffer layer In general, organic thin film solar cells often have a thin total film thickness, and therefore, the upper electrode and the lower electrode are short-circuited, and the yield of cell fabrication often decreases. In such a case, it is preferable to prevent this by laminating a buffer layer.
As a preferable compound for the buffer layer, a compound having sufficiently high carrier mobility is preferable so that the short-circuit current does not decrease even when the film thickness is increased. For example, if it is a low molecular compound, the aromatic cyclic acid anhydride represented by NTCDA shown below etc. will be mentioned, and if it is a high molecular compound, poly (3,4-ethylenedioxy) thiophene: polystyrene sulfonate (PEDOT: PSS), polyaniline: camphorsulfonic acid (PANI: CSA), and other known conductive polymers.

式中、ｎ，ｍは繰り返し数である。

In the formula, n and m are the number of repetitions.

  In addition, the buffer layer may have a role of preventing excitons from diffusing to the electrodes and deactivating. Inserting a buffer layer as an exciton blocking layer in this way is effective for increasing efficiency. The exciton blocking layer can be inserted on either the anode side or the cathode side, or both can be inserted simultaneously. In this case, as a preferable material for the exciton blocking layer, for example, a well-known material for a hole barrier layer or a material for an electron barrier layer in organic EL applications can be used. A preferable material for the hole blocking layer is a compound having a sufficiently large ionization potential, and a preferable material for the electron blocking layer is a compound having a sufficiently small electron affinity. Specifically, bathocuproin (BCP), bathophenanthroline (BPhen), and the like, which are well-known materials for organic EL applications, can be used as the cathode-side hole barrier layer material.

Furthermore, you may use the inorganic semiconductor compound illustrated as said n layer material for a buffer layer. As the p-type inorganic semiconductor compound, CdTe, p-Si, SiC, GaAs, WO ₃ or the like can be used.

5. Substrate The substrate preferably has mechanical and thermal strength and transparency. For example, there are a glass substrate and a transparent resin film. Transparent resin films include polyethylene, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, polypropylene, polystyrene, polymethyl methacrylate, polyvinyl chloride, polyvinyl alcohol, polyvinyl butyral, nylon, polyether ether ketone. , Polysulfone, polyethersulfone, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, polyvinyl fluoride, tetrafluoroethylene-ethylene copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, polychlorotrifluoroethylene, Polyvinylidene fluoride, polyester, polycarbonate, polyurethane, polyimide, polyetherimide, polyimide, polypropylene, etc. It is.

  The formation of each layer of the organic thin film solar cell of the present invention is performed by a dry film formation method such as vacuum deposition, sputtering, plasma, ion plating, or wet film formation such as spin coating, dip coating, casting, roll coating, flow coating, and ink jet. The law can be applied.

  The thickness of each layer is not particularly limited, but is set to an appropriate thickness. Since it is generally known that the exciton diffusion length of an organic thin film is short, if the film thickness is too thick, the exciton is deactivated before reaching the heterointerface, resulting in low photoelectric conversion efficiency. If the film thickness is too thin, pinholes and the like are generated, so that sufficient diode characteristics cannot be obtained, resulting in a decrease in conversion efficiency. The normal film thickness is suitably in the range of 1 nm to 10 μm, but more preferably in the range of 5 nm to 0.2 μm.

  In the case of the dry film forming method, a known resistance heating method is preferable, and for forming the mixed layer, for example, a film forming method by simultaneous vapor deposition from a plurality of evaporation sources is preferable. More preferably, the substrate temperature is controlled during film formation.

  In the case of a wet film forming method, a material for forming each layer is dissolved or dispersed in an appropriate solvent to prepare a light-emitting organic solution to form a thin film, and any solvent can be used. For example, halogenated hydrocarbon solvents such as dichloromethane, dichloroethane, chloroform, carbon tetrachloride, tetrachloroethane, trichloroethane, chlorobenzene, dichlorobenzene, chlorotoluene, ether solvents such as dibutyl ether, tetrahydrofuran, dioxane, anisole, methanol, Alcohol solvents such as ethanol, propanol, butanol, pentanol, hexanol, cyclohexanol, methyl cellosolve, ethyl cellosolve, ethylene glycol, hydrocarbon solvents such as benzene, toluene, xylene, ethylbenzene, hexane, octane, decane, tetralin, Examples include ester solvents such as ethyl acetate, butyl acetate, and amyl acetate. Of these, hydrocarbon solvents or ether solvents are preferable. These solvents may be used alone or in combination. In addition, the solvent which can be used is not limited to these.

In the present invention, in any organic thin film layer of the organic thin film solar cell, an appropriate resin or additive may be used for improving the film formability and preventing pinholes in the film. Usable resins include polystyrene, polycarbonate, polyarylate, polyester, polyamide, polyurethane, polysulfone, polymethyl methacrylate, polymethyl acrylate, cellulose and other insulating resins and copolymers thereof, poly-N-vinyl. Examples thereof include photoconductive resins such as carbazole and polysilane, and conductive resins such as polythiophene and polypyrrole.
Examples of the additive include an antioxidant, an ultraviolet absorber, and a plasticizer.

Example 1 (Synthesis of Compound A)
The raw material A of Compound A was synthesized by the following procedure.

窒素雰囲気下、原料Ａ（１．２ｇ，８．９ｍｍｏｌ）、ジフェニルアミン（０．４ｇ，２．４ｍｍｏｌ，１．２ｅｑ．）、トリス（ジベンジリデンアセトン）ジパラジウム（０）（０．０３ｇ，０．０３ｍｍｏｌ，３％Ｐｄ）、ナトリウムｔ−ブトキシド（０．３ｇ，２．８ｍｍｏｌ，１．４ｅｑ．）を無水トルエン（５０ｍｌ）に懸濁し、トリｔ−ブチルホスフィン／トルエン溶液（２．８Ｍ，０．０１７ｍｌ，０．０４８ｍｍｏｌ，Ｐｄに対して０．８ｅｑ．）を加えて７時間還流した。反応混合物をシリカゲルパッドを通してろ別し、トルエン（１００ｍｌ）で洗浄した。ろ液を溶媒留去して得られた赤色油状固体を、カラムクロマトグラフィ（シリカゲル／ヘキサン＋１７％ジクロロメタン、続いてヘキサン＋３３％ジクロロメタン）で精製して赤色固体（１．２ｇ，８６％）を得た。 Compound A was synthesized as follows.

In a nitrogen atmosphere, the raw material A (1.2 g, 8.9 mmol), diphenylamine (0.4 g, 2.4 mmol, 1.2 eq.), Tris (dibenzylideneacetone) dipalladium (0) (0.03 g, .0. 03 mmol, 3% Pd) and sodium t-butoxide (0.3 g, 2.8 mmol, 1.4 eq.) Were suspended in anhydrous toluene (50 ml), and a tri-t-butylphosphine / toluene solution (2.8 M, 0.8 ml) was suspended. 017 ml, 0.048 mmol, 0.8 eq. With respect to Pd) was added and refluxed for 7 hours. The reaction mixture was filtered off through a silica gel pad and washed with toluene (100 ml). The red oily solid obtained by evaporating the filtrate from the solvent was purified by column chromatography (silica gel / hexane + 17% dichloromethane, followed by hexane + 33% dichloromethane) to give a red solid (1.2 g, 86%). .

¹ H-NMR (400 MHz, CDCl ₃ , tetramethylsilane (TMS)) 6.68 (2H, d, J = 8 Hz), 6.93 (2H, t, J = 9 Hz), 7.06 to 7.08 (4H, m), 7.19-7.42 (6H, m), 7.59-7.72 (12H, m), 7.86 (1H, d, J = 9z), 7.95 (1H , D, J = 8 Hz), 7.99 (1H, d, J = 8 Hz), 8.17 (2H, d, J = 9 Hz), field desorption mass spectrometry (FDMS): calculated value C ₅₄ H ₃₅ N = 698, measured value m / z = 698 (M ⁺ , 100), high performance liquid chromatography (HPLC): 99.1% (UV254 area%), absorption maximum wavelength: 546 nm (dichloromethane), fluorescence maximum wavelength: 585 nm (Dichloromethane)
The solid (1.2 g) obtained above was purified by sublimation at 340 ° C./1.9×10 ⁻³ Pa to obtain a red solid (0.9 g).
HPLC: 95.7% (UV254 area%)

Example 2 (Manufacture of an organic thin film solar cell)
A glass substrate with an ITO transparent electrode having a thickness of 25 mm × 75 mm × 0.7 mm was subjected to ultrasonic cleaning in isopropyl alcohol for 5 minutes, and then UV ozone cleaning was performed for 30 minutes. The glass substrate with the transparent electrode line after cleaning is attached to the substrate holder of the vacuum deposition apparatus, and the film thickness is 30 nm so as to cover the transparent electrode on the surface where the transparent electrode line as the lower electrode is first formed. Compound A (p-type material) was formed at 1 Å / s by resistance heating vapor deposition.
Subsequently, C ₆₀ (n-type material) having a film thickness of 60 nm was formed on this compound A film at 1 Å / s by resistance heating vapor deposition. Furthermore, 10 nm bathocuproine (BCP) was deposited at 1 cm / s as a buffer layer. Finally, metal Al was deposited as a counter electrode to a thickness of 80 nm to form an organic solar cell. The area was 0.5 cm ² . The thus obtained organic solar cell was measured for IV characteristics under AM1.5 conditions (light intensity 100 mW / cm ² ). As a result, open circuit voltage (Voc), short circuit current density (Jsc), fill factor (FF), and conversion efficiency (η) are shown in Table 1.

Comparative Example 1
An organic solar cell was produced in the same manner as in Example 2 except that Compound A was changed to mTPD. The IV characteristics of the organic solar cell thus produced were measured under AM1.5 conditions (light intensity 100 mW / cm ² ). Table 1 shows the open-circuit voltage (Voc), the short-circuit current density (Jsc), the fill factor (FF), and the conversion efficiency (η).

Comparative Example 2
PFT was synthesized by the following procedure.

An organic solar cell was produced in the same manner as in Example 2 except that Compound A was changed to PFT. The IV characteristics of the organic solar cell thus produced were measured under AM1.5 conditions (light intensity 100 mW / cm ² ). Table 1 shows the open-circuit voltage (Voc), the short-circuit current density (Jsc), the fill factor (FF), and the conversion efficiency (η).

Comparative Example 3
RD was synthesized according to the following procedure described in JP2009-132673A.

An organic solar cell was produced in the same manner as in Example 2 except that Compound A was changed to RD. The IV characteristics of the organic solar cell thus produced were measured under AM1.5 conditions (light intensity 100 mW / cm ² ). Table 1 shows the open-circuit voltage (Voc), the short-circuit current density (Jsc), the fill factor (FF), and the conversion efficiency (η).

ここで、Ｖｏｃは開放端電圧、Ｊｓｃは短絡電流密度、ＦＦは曲線因子、Ｐｉｎは入射光エネルギーである。従って、同じＰｉｎに対して、Ｖｏｃ、Ｊｓｃ及びＦＦがいずれも大きな化合物ほど優れた変換効率を示す。 Generally, the photoelectric conversion efficiency (η) of a solar cell is expressed by the following equation.

Here, Voc is an open circuit voltage, Jsc is a short circuit current density, FF is a fill factor, and Pin is incident light energy. Therefore, for the same Pin, a compound having a larger Voc, Jsc and FF shows better conversion efficiency.

As can be seen from Table 1, the compound of the present invention has improved conversion efficiency as compared with conventional amine compounds and polycyclic fused ring compounds, and has been shown to exhibit excellent solar cell characteristics.
This is because mTPD has only short-wavelength absorption, PFT has little hole-transport property, and RD has both long-wavelength absorption and hole-transport property, but has a longer wavelength absorption width than the compound of the present invention. Is considered to be narrow.

  The compound of the present invention can be used for an organic thin film solar cell, and the organic thin film solar cell of the present invention can be used as a power source for various devices such as watches, mobile phones and mobile personal computers, and electrical appliances.

Claims (6)

An indenoperylene derivative represented by the formula ( 3 ).

(In the formula ( 3 ), R ₁ and R ₆ are each independently a substituted or unsubstituted phenyl group, 2-tolyl group or 4-tolyl group, and R _{2 to} R ₅ and R _{7 to} R ₁₅ are hydrogen. And R _a and R _b are substituted or unsubstituted phenyl groups, and when having a substituent, the substituent is a fluorine atom, a methoxy group, an ethoxy group, or a cyano group.) The indenoperylene derivative according to claim 1 , which is represented by the formula (4).

(In the formula, R ₁₀₁ to R ₁₀₄ , R _{110 to} R ₁₁₄ and R _{125 to} R ₁₂₈ are hydrogen atoms, and R _{105 to} R ₁₀₉ and R _{129 to} R ₁₃₃ are each independently a hydrogen atom, a methyl group, fluorine, An atom, a methoxy group, an ethoxy group, or a cyano group, and R _{115 to} R ₁₂₄ are each independently a hydrogen atom, a fluorine atom, a methoxy group, an ethoxy group, or a cyano group. An organic thin film solar cell material comprising the indenoperylene derivative according to claim 1 or 2 . The organic thin-film solar cell containing the indenoperylene derivative of Claim 1 or 2 . An organic thin film solar cell having at least a p layer, wherein the indenoperylene derivative according to claim 1 or 2 is used for the p layer. In the organic thin-film solar cell having at least p and n layers, using a fullerene derivative in the n-layer, an organic thin film solar cell using the indenoperylene derivative according to claim 1 or 2 in the p-layer.