JP6931891B2 - Fullerene derivatives and n-type semiconductor materials - Google Patents

Description

The present invention relates to fullerene derivatives, n-type semiconductor materials and the like.

Organic thin-film solar cells use an organic compound as a photoelectric conversion material and are formed by a coating method from a solution. 1) The cost at the time of device fabrication is low, 2) the area can be easily increased, and 3). Compared with inorganic materials such as silicon, it is flexible and can be used in a wider range of places, and 4) there is less concern about resource depletion, and so on. For this reason, the development of organic thin-film solar cells has been promoted in recent years, and in particular, by adopting a bulk heterojunction structure, it has become possible to greatly improve the conversion efficiency, which has attracted widespread attention.

Among the materials for photoelectric conversion base materials used in organic thin-film solar cells, p-type semiconductors are known as organic p-type semiconductor materials in which poly-3-hexylthiophene (P3HT) has excellent performance. Recently, aiming for higher functionality, compounds having a structure capable of absorbing a wide range of wavelengths of sunlight or a structure having an adjusted energy level have been developed (donor acceptor type π-conjugated polymer), which greatly improves performance. Contribution. Examples of such compounds include poly-p-phenylene vinylene, poly [[4,8-bis [(2-ethylhexyl) oxy] benzo [1,2-b: 4,5-b'] dithiophene-2. , 6-Diyl] [3-fluoro-2-[(2-ethylhexyl) carbonyl] thieno [3,4-b] thiophendiyl]] (PTB7).

On the other hand, fullerene derivatives have also been actively studied for n-type semiconductors, and [6,6] -phenyl C61-butyric acid methyl ester (PCBM) has been reported as a material having excellent photoelectric conversion performance (described later). See Patent Documents 1 and 2). However, with respect to fullerene derivatives other than PCBM, there are few examples that have been demonstrated to be able to stably achieve good conversion efficiency.

PCBM is a fullerene derivative having a three-membered ring portion, and most of the previously reported fullerene derivatives are fullerene derivatives having a three-membered ring portion like PCBM.

On the other hand, as a fullerene derivative other than the fullerene derivative having a 3-membered ring portion, a fullerene derivative having a 5-membered ring portion is also known, but there are few reports. Non-Patent Document 1 discloses a fullerene derivative having a pyrrolidine ring and having a substituent only at the 1-position and the 2-position thereof. Patent Document 3 describes a fullerene derivative having a pyrrolidine ring and having a substituent only at the 1-position and a 2-position thereof, and particularly, a fullerene derivative having a substituted or unsubstituted phenyl group at the 1-position. Is described as having high conversion efficiency when used as an n-type semiconductor of a solar cell. Patent Document 4 discloses a fullerene derivative having a pyrrolidine ring and having a substituent only at the 1-position and the 2-position thereof. Patent Document 5 discloses a fullerene derivative having two or more pyrrolidine rings. Non-Patent Document 2 discloses that a fullerene derivative having a pyrrolidine ring and a phenyl group at the 1-position thereof is effective as an n-type semiconductor for an organic thin film solar cell.

Japanese Unexamined Patent Publication No. 2009-84264 JP-A-2010-92964 Japanese Unexamined Patent Publication No. 2012-089538 International Publication No. 2014/185536 Japanese Unexamined Patent Publication No. 2011-181719

T. Itoh et al., Journal of Materials Chemistry, 2010, Vol. 20, p. 9226 M. Karakawa et al., Journal of Material Chemistry A, 2014, Volume 2, p. 20889

The device using the fullerene derivative described in Non-Patent Document 1 has achieved higher conversion efficiency than the device using PCBM, but this is a special device from which the current collecting material of the anode (ITO electrode) has been removed. It is a comparison in composition.
As described above, a practical organic thin-film solar cell using a fullerene derivative has not yet been developed, and a new fullerene derivative that can be used for applications such as n-type semiconductor materials for organic thin-film solar cells is still available. Development is required.

A main object of the present invention is to provide a material having excellent performance as an n-type semiconductor, particularly an n-type semiconductor for a photoelectric conversion element such as an organic thin film solar cell.

As an excellent performance as an n-type semiconductor for a photoelectric conversion element such as an organic thin film solar cell, high conversion efficiency is typically exemplified.
Therefore, one of the objects of the present invention is to provide a new fullerene derivative capable of achieving high conversion efficiency.

Normally, a drive voltage above a certain level is required to operate electrical equipment. Therefore, when the output voltage of one cell of the solar cell is low, a large number of cells are required. Here, if an n-type semiconductor capable of generating a high voltage is provided, the number of required cells can be reduced, and therefore the space of the solar cell can be saved.
That is, there is a demand for a material that can easily form a thin film by a coating method and can exhibit high power generation efficiency in device fabrication.
Therefore, one of the objects of the present invention is to provide a new fullerene derivative that facilitates device fabrication and enables high voltage output.
Therefore, an object of the present invention is to provide a fullerene derivative having high conversion efficiency and enabling high voltage output.

The present inventors have found that the above-mentioned problems can be solved by a fullerene derivative represented by the following formula (1).

The present invention includes the following aspects.

［式中、
X^１ａは、水素原子、塩素原子、臭素原子、ヨウ素原子、１個以上の置換基を有していてもよいアルキル基、１個以上の置換基を有していてもよいアルコキシ基、又はシアノ基を表し、
X^１ｂは、塩素原子、臭素原子、ヨウ素原子、１個以上の置換基を有していてもよいアルキル基、１個以上の置換基を有していてもよいアルコキシ基、又はシアノ基を表し、
Ｒ^２は、１個以上の置換基を有していてもよいアリール基、又は１個以上の置換基を有していてもよいヘテロアリール基を表し、
Ｒ^３は、水素原子、又は有機基を表し、及び
環Ａは、フラーレン環
を表す。］
で表されるフラーレン誘導体。
項２．
X^１ａは、水素原子、塩素原子、臭素原子、ヨウ素原子、メチル基、メトキシ基、又はシアノ基である項１に記載のフラーレン誘導体。
項３．
X^１ａは、塩素原子、臭素原子、ヨウ素原子、メチル基、メトキシ基、又はシアノ基である項２に記載のフラーレン誘導体。
項４．
X^１ｂは、塩素原子、臭素原子、ヨウ素原子、メチル基、メトキシ基、又はシアノ基である項１〜３のいずれか１項に記載のフラーレン誘導体。
項５．
Ｒ^２は、１個以上の置換基を有していてもよいアリール基である項１〜４のいずれか１項に記載のフラーレン誘導体。
項６．
Ｒ^２は、オルト位に１個、又は２個の置換基を有していてもよいフェニル基である項５に記載のフラーレン誘導体。
項７．
Ｒ^３は、水素原子、又はアルキル基である項１〜６のいずれか１項に記載のフラーレン誘導体。
項８．
環Ａは、Ｃ_６０フラーレン環である項１〜７のいずれか１項に記載のフラーレン誘導体。
項９．
項１〜８のいずれか１項に記載のフラーレン誘導体を含有するｎ型半導体材料。
項１０．
有機薄膜太陽電池用である項９に記載のｎ型半導体材料。
項１１．
項１０に記載のｎ型半導体材料を含有する有機発電層。
項１２．
項１１に記載の有機発電層を備える光電変換素子。
項１３．
有機薄膜太陽電池である、項１２に記載の光電変換素子。Item 1.
Equation (1):

[During the ceremony,
X ^1a is a hydrogen atom, a chlorine atom, a bromine atom, an iodine atom, an alkyl group which may have one or more substituents, an alkoxy group which may have one or more substituents, or a cyano. Represents a group
X ^1b represents a chlorine atom, a bromine atom, an iodine atom, an alkyl group which may have one or more substituents, an alkoxy group which may have one or more substituents, or a cyano group. ,
R ² represents an aryl group which may have one or more substituents or a heteroaryl group which may have one or more substituents.
R ³ represents a hydrogen atom or an organic group, and ring A represents a fullerene ring. ]
Fullerene derivative represented by.
Item 2.
Item 2. The fullerene derivative according to Item 1, wherein X ^1a is a hydrogen atom, a chlorine atom, a bromine atom, an iodine atom, a methyl group, a methoxy group, or a cyano group.
Item 3.
Item 2. The fullerene derivative according to Item 2, wherein X ^1a is a chlorine atom, a bromine atom, an iodine atom, a methyl group, a methoxy group, or a cyano group.
Item 4.
Item 3. The fullerene derivative according to any one of Items 1 to 3, wherein X ^1b is a chlorine atom, a bromine atom, an iodine atom, a methyl group, a methoxy group, or a cyano group.
Item 5.
Item 2. The fullerene derivative according to any one of Items 1 to 4, wherein R ^{2 is an aryl group which may have one or more substituents.}
Item 6.
Item 2. The fullerene derivative according to Item 5, wherein R ² is a phenyl group which may have one or two substituents at the ortho position.
Item 7.
Item 2. The fullerene derivative according to any one of Items 1 to 6, wherein R ^{3 is a hydrogen atom or an alkyl group.}
Item 8.
Ring A _is a fullerene derivative according to any one of claim 1 to 7 is a _{C 60} fullerene ring.
Item 9.
An n-type semiconductor material containing the fullerene derivative according to any one of Items 1 to 8.
Item 10.
Item 9. The n-type semiconductor material for organic thin-film solar cells.
Item 11.
Item 10. An organic power generation layer containing the n-type semiconductor material according to Item 10.
Item 12.
Item 2. The photoelectric conversion element including the organic power generation layer according to Item 11.
Item 13.
Item 12. The photoelectric conversion element according to Item 12, which is an organic thin-film solar cell.

According to the present invention, a fullerene derivative having high conversion efficiency and enabling high voltage output is provided.

Terms The symbols and abbreviations herein are in the context of the present specification and can be understood in the meaning commonly used in the art to which the present invention belongs, unless otherwise specified.
In the present specification, the phrase "contains" is used with the intention of including the phrase "consisting of" and the phrase "consisting of".
Unless otherwise specified, the steps, treatments, or operations described herein can be performed at room temperature.
In the present specification, room temperature means a temperature in the range of 10 to 40 ° C.

In the present specification, unless otherwise specified, "organic group" means a group containing one or more carbon atoms as its constituent atoms.

In the present specification, unless otherwise specified, the "organic group" is exemplified by a hydrocarbon group.

In the present specification, unless otherwise specified, "hydrocarbon group" means a group containing one or more carbon atoms and one or more hydrogen atoms as its constituent atoms. In the present specification, the hydrocarbon group may be referred to as a hydrocarbyl group.

In the present specification, unless otherwise specified, the "hydrocarbon group" includes an aliphatic hydrocarbon group (eg, a benzyl group) which may be substituted with one or more aromatic hydrocarbon groups, and one. An example is an aromatic hydrocarbon group (aryl group) which may be substituted with the above aliphatic hydrocarbon group.

In the present specification, unless otherwise specified, the "aliphatic hydrocarbon group" can be linear, branched, cyclic, or a combination thereof.

In the present specification, unless otherwise specified, the "aliphatic hydrocarbon group" can be saturated or unsaturated.

In the present specification, unless otherwise specified, examples of the "aliphatic hydrocarbon group" include an alkyl group, an alkenyl group, an alkynyl group, and a cycloalkyl group.

In the present specification, unless otherwise specified, "alkyl groups" include, for example, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl, neopentyl, hexyl and the like. , Linear or branched alkyl groups having 1 to 10 carbon atoms are exemplified.

In the present specification, unless otherwise specified, the "alkenyl group" includes, for example, vinyl, 1-propenyl, isopropenyl, 2-methyl-1-propenyl, 1-butenyl, 2-butenyl, 3-butenyl, 2 -Ethyl-1-butenyl, 1-pentenyl, 2-pentenyl, 3-pentenyl, 4-pentenyl, 4-methyl-3-pentenyl, 1-hexenyl, 2-hexenyl, 3-hexenyl, 4-hexenyl, and 5- A linear or branched alkenyl group having 2 to 10 carbon atoms such as hexenyl is exemplified.

In the present specification, unless otherwise specified, the "alkynyl group" includes, for example, ethynyl, 1-propynyl, 2-propynyl, 1-butynyl, 2-butynyl, 3-butynyl, 1-pentynyl, 2-pentynyl, and the like. Linear or branched alkynyl groups with 2 to 6 carbon atoms, such as 3-pentynyl, 4-pentynyl, 1-hexynyl, 2-hexynyl, 3-hexynyl, 4-hexynyl, and 5-hexynyl. Is exemplified.

In the present specification, unless otherwise specified, examples of the "cycloalkyl group" include cycloalkyl groups having 3 to 8 carbon atoms such as cyclopentyl group, cyclohexyl group, and cycloheptyl.

In the present specification, unless otherwise specified, the "alkoxy group" is, for example, a group represented by RO- (in the formula, R is an alkyl group).

In the present specification, unless otherwise specified, "ester group" means an organic group having an ester bond (that is, −C (= O) −O− or −OC (= O) −). Examples are a group represented by the formula: RCO _2- (in the formula, R is an alkyl group) and a formula: R ^a- CO _2- R ^b- (in the formula, R ^a is an alkyl group). And R ^b is an alkylene group).

In the present specification, unless otherwise specified, "ether group" means a group having an ether bond (-O-).

Examples of "ether groups" include polyether groups. Examples of polyether groups are of the formula: ^Ra − (OR ^b ) _n − (in the formula, ^Ra is an alkyl group, R ^b is the same or different in each appearance, is an alkylene group, and n is an integer greater than or equal to 1). The alkylene group is a divalent group formed by removing one hydrogen atom from the alkyl group.

Examples of "ether groups" also include hydrocarbyl ether groups. Hydrocarbyl ether group means a hydrocarbon group having one or more ether bonds. The "hydrocarbyl group having one or more ether bonds" can be a hydrocarbyl group into which one or more ether bonds are inserted. Examples include the benzyloxy group.

Examples of "hydrocarbon groups having one or more ether bonds" include alkyl groups having one or more ether bonds. The "alkyl group having one or more ether bonds" can be an alkyl group into which one or more ether bonds are inserted. In the present specification, such a group may be referred to as an alkyl ether group.

In the present specification, unless otherwise specified, the "acyl group" includes an alkanoyl group. In the present specification, unless otherwise specified, the "alkanoyl group" is, for example, a group represented by RCO- (in the formula, R is an alkyl group).

Unless otherwise noted herein, the "aryl group" can be monocyclic, bicyclic, tricyclic or tetracyclic.
Unless otherwise specified in the present specification, the "aryl group" can be an aryl group having 6 to 18 carbon atoms.
Unless otherwise specified, examples of the "aryl group" in the present specification include phenyl, 1-naphthyl, 2-naphthyl, 2-biphenyl, 3-biphenyl, 4-biphenyl, and 2-anthrill.

Unless otherwise specified, the "heteroaryl group" herein is, for example, a monocyclic, bicyclic, tricyclic, or tetracyclic, 5- to 18-membered heteroaryl group. Can be done.
Unless otherwise specified, in the present specification, the "heteroaryl group" includes, for example, 1 to 4 heteroatoms selected from oxygen atoms, sulfur atoms, and nitrogen atoms in addition to carbon atoms as ring-constituting atoms. It is a heteroaryl group contained. The "heteroaryl group" can have, for example, 3 to 17 carbon atoms.
In the present specification, unless otherwise specified, the "heteroaryl group" includes a "monocyclic heteroaryl group" and an "aromatic condensed heterocyclic group".

In the present specification, unless otherwise specified, "monocyclic heteroaryl group" includes, for example, pyrrolyl (eg, 1-pyrrolyl, 2-pyrrolill, 3-pyrrolill), frill (eg, 2-furyl, 3). -Frill), thienyl (eg, 2-thienyl, 3-thienyl), pyrazolyl (eg, 1-pyrazolyl, 3-pyrazolyl, 4-pyrazolyl), imidazolyl (eg, 1-imidazolyl, 2-imidazolyl, 4-imidazolyl) , Isooxazolyl (eg, 3-isoxazolyl, 4-isooxazolyl, 5-isoxazolyl), oxazolyl (eg, 2-oxazolyl, 4-oxazolyl, 5-oxazolyl), isothiazolyl (eg, 3-isothiazolyl, 4-isothiazolyl, 5-isothiazolyl). ), Thiazolyl (eg, 2-thiazolyl, 4-thiazolyl, 5-thiazolyl), triazolyl (eg, 1,2,3-triazol-4-yl, 1,2,4-triazol-3-yl), oxadiazolyl (eg, 1,2,4-triazol-3-yl) Examples, 1,2,4-oxadiazole-3-yl, 1,2,4-oxadiazole-5-yl), thiadiazole (eg, 1,2,4-thiadiazole-3-yl, 1,2) , 4-Thiadiazole-5-yl), tetrazolyl, pyridyl (eg, 2-pyridyl, 3-pyridyl, 4-pyridyl), pyridadinyl (eg, 3-pyridazinyl, 4-pyridazinyl), pyrimidinyl (eg, 2-pyrimidinyl, 4-pyrimidinyl, 5-pyrimidinyl), pyrazinyl and the like can be mentioned.

Unless otherwise specified, the "aromatically fused heterocyclic group" in the present specification includes, for example, isoindolyl (eg, 1-isoindrill, 2-isoindrill, 3-isoindrill, 4-isoindrill, 5-isoindol, 6- Isoindrill, 7-isoindrill), indrill (eg, 1-indrill, 2-indrill, 3-indrill, 4-indrill, 5-indrill, 6-indrill, 7-indrill), benzo [b] furanyl (eg, 2-indrill) Benzo [b] flanyl, 3-benzo [b] flanyl, 4-benzo [b] flanyl, 5-benzo [b] flanyl, 6-benzo [b] flanil, 7-benzo [b] flanyl), benzo [c] ] Furanyl (eg, 1-benzo [c] flanyl, 4-benzo [c] flanyl, 5-benzo [c] flanyl), benzo [b] thienyl, (eg, 2-benzo [b] thienyl, 3-benzo) [B] thienyl, 4-benzo [b] thienyl, 5-benzo [b] thienyl, 6-benzo [b] thienyl, 7-benzo [b] thienyl), benzo [c] thienyl (eg, 1-benzo [e.g.] c] Thienyl, 4-benzo [c] thienyl, 5-benzo [c] thienyl), indazolyl (eg, 1-indazolyl, 2-indazolyl, 3-indazolyl, 4-indazolyl, 5-indazolyl, 6-indazolyl, 7 -Indazolyl), benzoimidazolyl (eg, 1-benzoimidazolyl, 2-benzoimidazolyl, 4-benzoimidazolyl, 5-benzoimidazolyl), 1,2-benzoisoxazole (eg, 1,2-benzoisoxazole-3-yl, 1) , 2-benzoisoxazole-4-yl, 1,2-benzoisoxazole-5-yl, 1,2-benzoisoxazole-6-yl, 1,2-benzoisoxazole-7-yl), benzoxal Zoryl (eg, 2-benzoxazolyl, 4-benzoxazolyl, 5-benzoxazolyl, 6-benzoxazolyl, 7-benzoxazolyl), 1,2-benzothiazolyl (eg, 2-benzoxazolyl, 1,2-benzoxazolyl) Examples, 1,2-benzoisothiazole-3-yl, 1,2-benzoisothiazole-4-yl, 1,2-benzoisothiazole-5-yl, 1,2-benzoisothiazole-6-yl, 1,2-benzoisothiazole-7-yl), benzothiazolyl (eg, 2-benzothiazolyl, 4-benzothiazolyl, 5-benzothiazolyl, 6-benzothiazolyl, 7-benzothiazolyl), isoquinolyl (eg, 1- Isoquinolyl, 3-isoquinolyl, 4-isoquinolyl, 5-isoquinolyl), quinolyl (eg, 2-quinolyl, 3-quinolyl, 4-quinolyl, 5-quinolyl, 8-quinolyl), cinnolinyl (eg, 3-cinnolinyl, 4- Synnolinyl, 5-cinnolinyl, 6-cinnolinyl, 7-cinnolinyl, 8-cinnolinyl), phthalazinyl (eg, 1-phthalazinyl, 4-phthalazinyl, 5-phthalazinyl, 6-phthalazinyl, 7-phthalazinyl, 8-phthalazinyl), quinazolinyl (eg, 1-phthalazinyl, 4-phthalazinyl, 5-phthalazinyl, 8-phthalazinyl) Examples, 2-quinazolinyl, 4-quinazolinyl, 5-quinazolinyl, 6-quinazolinyl, 7-quinazolinyl, 8-quinazolinyl), quinoxalinyl (eg, 2-quinoxalinyl, 3-quinoxalinyl, 5-quinoxalinyl, 6-quinoxalinyl, 7-quinoxalinyl). , 8-Kinoxalinyl), pyrazolo [1,5-a] pyridyl (eg, pyrazolo [1,5-a] pyridin-2-yl, pyrazolo [1,5-a] pyridin-3-yl, pyrazolo [1,5] 5-a] Pyridine-4-yl, Pyrazoro [1,5-a] Pyridine-5-yl, Pyrazoro [1,5-a] Pyridine-6-yl, Pyrazoro [1,5-a] Pyridine-7- Il), imidazo [1,2-a] pyridyl (eg, imidazo [1,2-a] pyridin-2-yl, imidazo [1,2-a] pyridin-3-yl, imidazo [1,2-a] ] Pyridine-5-yl, imidazo [1,2-a] pyridin-6-yl, imidazo [1,2-a] pyridin-7-yl, imidazo [1,2-a] pyridin-8-yl), etc. Can be mentioned.

In the present specification, unless otherwise specified, "alkyl groups" include, for example, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl, neopentyl, hexyl and the like. , Linear or branched alkyl groups having 1 to 10 carbon atoms are exemplified.

Hereinafter, the fullerene derivative of the present invention, an n-type semiconductor material containing the fullerene derivative, and the like will be specifically described.

Fullerene derivative The fullerene derivative of the present invention is a fullerene derivative represented by the following formula (1).

［式中、
X^１ａは、水素原子、塩素原子、臭素原子、ヨウ素原子、１個以上の置換基を有していてもよいアルキル基、１個以上の置換基を有していてもよいアルコキシ基、又はシアノ基を表し、
X^１ｂは、塩素原子、臭素原子、ヨウ素原子、１個以上の置換基を有していてもよいアルキル基、１個以上の置換基を有していてもよいアルコキシ基、又はシアノ基を表し、
Ｒ^２は、１個以上の置換基を有していてもよいアリール基、又は１個以上の置換基を有していてもよいヘテロアリール基を表し、
Ｒ^３は、水素原子、又は有機基を表し、及び
環Ａは、フラーレン環を表す。］Equation (1):

[During the ceremony,
X ^1a is a hydrogen atom, a chlorine atom, a bromine atom, an iodine atom, an alkyl group which may have one or more substituents, an alkoxy group which may have one or more substituents, or a cyano. Represents a group
X ^1b represents a chlorine atom, a bromine atom, an iodine atom, an alkyl group which may have one or more substituents, an alkoxy group which may have one or more substituents, or a cyano group. ,
R ² represents an aryl group which may have one or more substituents or a heteroaryl group which may have one or more substituents.
R ³ represents a hydrogen atom or an organic group, and ring A represents a fullerene ring. ]

X ^1a is preferably a hydrogen atom, a chlorine atom, a bromine atom, an iodine atom, a methyl group, a methoxy group, or a cyano group.

X ^1a is more preferably a chlorine atom, a bromine atom, an iodine atom, a methyl group, a methoxy group, or a cyano group.

X ^1a is more preferably a chlorine atom, a methyl group, a methoxy group, or a cyano group.

X ^1b is preferably a chlorine atom, a bromine atom, an iodine atom, a methyl group, a methoxy group, or a cyano group.

X ^1b is more preferably a chlorine atom, a bromine atom, a methyl group, a methoxy group, or a cyano group.

X ^1b is more preferably a chlorine atom, a methyl group, a methoxy group, or a cyano group.

X ^1a and X ^1b are preferably the same or different, chlorine atom, bromine atom, iodine atom, methyl group, methoxy group, or cyano group.

X ^1a and X ^1b are more preferably the same or different chlorine atoms, methyl groups, methoxy groups, or cyano groups.

The preferred X ^1a and preferred X ^1b may be electron-withdrawing groups or electron-donating groups, respectively.

The fullerene derivative of the present invention can have excellent properties as an n-type semiconductor material ^{, especially when X 1a} and X ^{1b are such groups.}
Specifically, for example, when used in an n-type semiconductor for a photoelectric conversion element such as an organic thin film solar cell, a high voltage can be applied.

Examples of substituents of the "one or more optionally substituted aryl group" represented by R ^2,
(a) Fluorine atom,
(b) Alkyl groups optionally substituted with one or more fluorine atoms,
(c) Alkoxy groups optionally substituted with one or more fluorine atoms,
(d) Ester group and
(e) Includes a cyano group.

The number of the substituents is, for example, 0 (unsubstituted), 1, 2, 3, 4, or 5.

Examples of substituents of the "one or more heteroaryl group optionally having substituents" represented by R ^2,
(a) Fluorine atom,
(b) Alkyl groups optionally substituted with one or more fluorine atoms,
(c) Alkoxy groups optionally substituted with one or more fluorine atoms,
(d) Ester group and
(e) Includes a cyano group.

The number of the substituents is, for example, 0 (unsubstituted), 1, 2, 3, 4, or 5.

R ² is preferably
(a) Fluorine atom,
(b) Alkyl groups optionally substituted with one or more fluorine atoms,
(c) Alkoxy groups optionally substituted with one or more fluorine atoms,
(d) Ester group and
(e) It may be substituted with one or more substituents selected from the group consisting of cyano groups.
It is an aryl group (preferably a phenyl group).

When R ² is a phenyl group having one or more substituents, the positions of the substituents can be, for example, the ortho-position, the meta-position, or the para-position.

R ² is preferably a phenyl group which may have one or two substituents at the ortho position.

R ³ is preferably
Hydrogen atom,
Alkyl groups that may be substituted with one or more substituents,
An alkenyl group which may be substituted with one or more substituents,
An alkynyl group which may be substituted with one or more substituents,
Aryl groups that may be substituted with one or more substituents,
An ether group that may be substituted with one or more substituents, or an ester group that may be substituted with one or more substituents.

As R ^3,
"Alkyl groups optionally substituted with one or more substituents",
"An alkenyl group optionally substituted with one or more substituents",
"Alkynyl group optionally substituted with one or more substituents",
"Aryl groups optionally substituted with one or more substituents",
"Ether groups optionally substituted with one or more substituents" and "Ester groups optionally substituted with one or more substituents"
Examples of the substituent in each "substituent" in the above are an alkyl group optionally substituted with one or more fluorine atoms, an alkoxy group and an ester group optionally substituted with one or more fluorine atoms. , And a cyano group. The number of the substituents can be 1 or more and not more than the maximum number that can be substituted, and is preferably, for example, 1 to 4, 1 to 3, 1 to 2, or 1.

R ³ is more preferably
Hydrogen atom,
An alkyl group having 2 to 18 carbon atoms (preferably 3 to 12, more preferably 4 to 10, still more preferably 5 to 10, still more preferably 5 to 8).
One or more substituents selected from a fluorine atom, an alkyl group optionally substituted with one or more fluorine atoms, an alkoxy group optionally substituted with one or more fluorine atoms, an ester group, and a cyano group. An aryl group (preferably a phenyl group) which may be substituted with,
An ether group (preferably an alkyl ether group) having 1 to 12 carbon atoms (preferably 1 to 10, more preferably 1 to 8 and even more preferably 1 to 6), or 2 to 12 carbon atoms (preferably 2 to 10). , More preferably 2-8, still more preferably 2-6) ester groups.

R ³ is more preferably
Alkyl groups having 2 to 18 carbon atoms (preferably 3 to 12, more preferably 4 to 10 and even more preferably 5 to 8).
An ether group having 1 to 12 carbon atoms (preferably 1 to 10, more preferably 1 to 8 and even more preferably 1 to 6), or 2 to 12 carbon atoms (preferably 2 to 10, more preferably 2 to 8). More preferably, it is an ester group of 2 to 6).

R ³ is even more preferably an alkyl group having 1 to 8 carbon atoms or an ether group having 5 to 6 carbon atoms.

R ³ is particularly preferably a methyl group, a hexyl group, a 2-ethylhexyl group, CH _3- (CH ₂ ) _2- O-CH _2- , or CH _3- O- (CH _{2 ) 2-} O- (CH). ₂ ) _2- O-CH _2- .

In one preferred embodiment of the present invention, R ³ is hydrogen atom, or an alkyl group.
In the corresponding, ^{R 3} is preferably,
(1) Hydrogen atom or
(2) Linear or branched chain with 2 to 18 carbon atoms (preferably 3 to 12, more preferably 4 to 10, still more preferably 5 to 10, and even more preferably 5 to 8). It is an alkyl group.

Ring A is preferably a C ₆₀ fullerene ring, or a C ₇₀ fullerene ring, and more preferably a C ₆₀ fullerene ring.

Ring A is preferably _{a, C 60} fullerene ring.

The fullerene derivatives of the formula (1) are a fullerene derivative in which ring A is a C ₆₀ fullerene ring (hereinafter, _{also referred to as a C 60} fullerene derivative), and _{a fullerene derivative in which ring A is a C 70} fullerene ring (hereinafter, C ₇₀ fullerene). It may also be a mixture of (also referred to as a derivative).

The ratio of the contents of the C ₆₀ fullerene derivative and the C ₇₀ fullerene derivative in the mixture is, for example, 99.999: 0.001 to 0.001: 99.999, 99.99: 0.01 to, in terms of molar ratio. 0.01: 99.99, 99.9: 0.1 to 0.1: 99.9, 99: 1 to 1:99, 95: 5 to 5:95, 90:10 to 10:90, or 80 : 20 to 20:80.
The ratio of the contents of the C ₆₀ fullerene derivative and the C ₇₀ fullerene derivative can be preferably 80:20 to 50:50, more preferably 80:20 to 60:40.
In the _mixture, the content of _{C 60} fullerene derivatives are, for example, 0.001 to 99.999% by weight, 0.01 to 99.99 mass%, 0.1 to 99.9 wt%, 99 wt% , 5 to 95% by mass, 10 to 90% by mass, or 20 to 80% by mass.
The content of the _{C 60} fullerene derivative is preferably 50 to 80 wt%, and more preferably, may be 60 to 80 mass%.
In the _mixture, the content of _{C 70} fullerene derivatives are, for example, 0.001 to 99.999% by weight, 0.01 to 99.99 mass%, 0.1 to 99.9 wt%, 99 wt% , 5 to 95% by mass, 10 to 90% by mass, or 20 to 80% by mass.
The content of the _{C 70} fullerene derivative is preferably 20 to 50 wt%, and more preferably, may be 20 to 40 mass%.
The mixture can substantially consist of a C ₆₀ fullerene derivative and a C ₇₀ fullerene derivative.
The mixture can consist of a C ₆₀ fullerene derivative and a C ₇₀ fullerene derivative.
The mixture can be a mixture of a C ₆₀ fullerene derivative and a C ₇₀ fullerene derivative.

で表す場合がある。In this specification, the C ₆₀ fullerene (ring), in the art, as often done, the following structure formula:

It may be represented by.

で表すことができる。Therefore, when Ring A is a C ₆₀ fullerene ring, the fullerene derivative of the formula (1) have the general formula:

Can be represented by.

In a preferred embodiment of the present invention
X ^1a is a hydrogen atom, a chlorine atom, a bromine atom, an iodine atom, a methyl group, a methoxy group, or a cyano group.
X ^1b is a chlorine atom, a bromine atom, an iodine atom, a methyl group, a methoxy group, or a cyano group.
R ² is an aryl group that may have one or more substituents, or a heteroaryl group that may have one or more substituents.
R ³ is a hydrogen atom or an alkyl group, and ring A is a C ₆₀ or C ₇₀ fullerene ring (preferably a C ₆₀ fullerene ring).

In another preferred embodiment of the invention,
X ^1a is a chlorine atom, a methyl group, a methoxy group, or a cyano group.
X ^1b is a chlorine atom, a methyl group, a methoxy group, or a cyano group.
R ² is a phenyl group
R ³ is a hydrogen atom or an alkyl group having 5 to 10 carbon atoms, and ring A is a C ₆₀ or C ₇₀ fullerene ring (preferably a C ₆₀ fullerene ring).

In yet another preferred embodiment of the invention,
X ^1a is a linear or branched alkyl group having 2 to 8 carbon atoms.
X ^1b is a linear or branched alkyl group having 2 to 8 carbon atoms.
R ² is an aryl group that may have one or more substituents, or a heteroaryl group that may have one or more substituents.
R ³ is a hydrogen atom or an alkyl group having 5 to 10 carbon atoms, and ring A is a C ₆₀ or C ₇₀ fullerene ring (preferably a C ₆₀ fullerene ring).

Since the fullerene derivative of the present invention exhibits sufficient solubility in various organic solvents, it is easy to form a thin film by a coating method.
Further, the fullerene derivative of the present invention can easily form a bulk heterojunction structure when an organic power generation layer is prepared by using it together with an organic p-type semiconductor material as an n-type semiconductor material.
The fullerene derivative of the present invention has high conversion efficiency and enables high voltage output.

The fullerene derivative of the present invention preferably has a LUMO level value of -3.65 eV or higher.
The LUMO level can be measured by the method described in Karakawa et al. Journal of Materials Chemistry A, 2014, Vol. 2, p. 20889.

Method for Producing Fullerene Derivative The fullerene derivative of the present invention can be produced by a known method for producing a fullerene derivative or a method similar thereto.
Specifically, the fullerene derivative of the present invention can be synthesized, for example, according to the method of the following scheme. The symbols in the scheme have the same meanings as described above, and as will be apparent to those skilled in the art, each symbol in formula (a) and formula (b) corresponds to each symbol in formula (1).

<Step A>
In step A, the glycine derivative (compound (b)) is reacted with an aldehyde compound (compound (a)) and fullerene (compound (c)), and the fullerene derivative represented by the formula (1) (compound (1)). To get.

The amount ratio of the aldehyde compound (compound (a)), the glycine derivative (compound (b)) and the fullerene (compound (c)) is arbitrary, but from the viewpoint of increasing the yield, the fullerene (compound (c)) 1 is usually used. The aldehyde compound (compound (a)) and the glycine derivative (compound (b)) are used in an amount of 0.1 to 10 mol, preferably 0.5 to 2 mol, respectively, based on the molar amount.

The reaction is carried out in a solvent-free or solvent-free manner.
Examples of the solvent include carbon disulfide, chloroform, dichloroethane, toluene, xylene, chlorobenzene, dichlorobenzene and the like. Of these, chloroform, toluene, xylene, chlorobenzene and the like are preferable. These solvents may be mixed and used in an appropriate ratio.

The reaction temperature is usually in the range of room temperature to about 150 ° C, preferably in the range of about 80 to about 120 ° C. Here, the room temperature can be preferably in the range of 15 to 30 ° C.

The reaction time is usually in the range of about 1 hour to about 4 days, preferably in the range of about 10 to about 48 hours.

The obtained compound (1) can be purified by a conventional purification method, if necessary.
For example, the obtained compound (1) is purified by silica gel column chromatography (preferably, for example, hexane-chloroform, hexane-toluene, or hexane-carbon disulfide as the developing solvent), and then further HPLC ( It can be purified by preparative GPC) (for example, chloroform or toluene is preferable as the developing solvent).

The aldehyde compound (compound (a)), glycine derivative (compound (b)) and fullerene (compound (c)) used in the step A are known compounds, respectively, and are known methods or the same. Synthesized by method or commercially available.

Specifically, the aldehyde compound (compound (a)) can be synthesized, for example, by the method (a1), (a2) or (a3) described later.
In the reaction formula indicated these methods, R ² has the same meaning as R ² in the formula (1), corresponding to R ² of the fullerene derivative of interest.

The method ^(a1): the oxide oxidation in the method of the alcohol represented by R 2 _-CH 2 OH, the known methods include, for example, (i) chromic acid as an oxidizing agent, a method using a manganese oxide or the like, (ii) Swern oxidation using dimethyl sulfoxide as an oxidizing agent, or a method of oxidizing using hydrogen peroxide, oxygen, air, or the like in the presence of a (iii) catalyst can be applied.

The method (a2): a carboxylic acid represented by R ² -COOH, the acid halide, an ester thereof, or reducing the reduction in this method such as the acid amide, a known method, for example, (i) a metal as a reducing agent A method using a hydride, (ii) a method of reducing hydrogen in the presence of a catalyst, (iii) a method using hydrazine as a reducing agent, and the like can be applied.

The method ^{(a3): R 2 -X (} . X is representing halogen) in the carbonylation in the carbonylation this method halide represented by, for example, forming an anion from the halide with n-BuLi A method of introducing a carbonyl group into this can be applied. As the carbonyl group introduction reagent here, an amide compound such as N, N-dimethylformamide (DMF); or an N-formyl derivative of piperidine, morpholine, piperazine or pyrrolidine is used.

を表す。Specifically, the glycine derivative (compound (b)) can be synthesized, for example, by the method (b1), (b2) or (b3) described later.
In the following synthesis scheme, R ¹ is the partial structure in equation (1):

Represents.

当該反応は、水、メタノール、エタノール、又はそれらの混合物などを溶媒として用い、及び必要に応じて塩基の存在下で実施できる。 Method (b1): Reaction of aniline derivative with acetic acid halide

The reaction can be carried out using water, methanol, ethanol, or a mixture thereof as a solvent, and if necessary, in the presence of a base.

この方法において、アニリン誘導体とハロゲン化酢酸エステルの反応は、例えば、メタノール、エタノールなどを溶媒として用い、酢酸塩、炭酸塩、リン酸塩、３級アミンなどの塩基の存在下に行うことができる。グリシン誘導体エステルの加水分解は、通常、水溶性アルカリの存在下に、室温で行うことができる。 Method (b2): Reaction of aniline derivative with halogenated acetate, and hydrolysis of glycine derivative ester obtained by the reaction.

In this method, the reaction between the aniline derivative and the halogenated acetate can be carried out using, for example, methanol, ethanol or the like as a solvent in the presence of a base such as acetate, carbonate, phosphate or tertiary amine. .. Hydrolysis of the glycine derivative ester can usually be carried out at room temperature in the presence of a water-soluble alkali.

この反応は、例えば、触媒として一価銅を用い、及びバルキーなアミン、アミノ酸、又はアミノアルコールなどの存在下で行うことができる。反応溶媒としては、水、メタノール、エタノール、又はこれらの混合物が好ましく用いられる。反応温度は、室温〜１００℃程度である。 Method (b3): Reaction of aromatic halides with glycine

This reaction can be carried out, for example, using monovalent copper as a catalyst and in the presence of bulky amines, amino acids, amino alcohols and the like. As the reaction solvent, water, methanol, ethanol, or a mixture thereof is preferably used. The reaction temperature is about room temperature to 100 ° C.

Since the fullerene derivative of the present invention can be synthesized by a simple method using the glycine derivative and the aldehyde compound as raw materials in this way, it can be produced at low cost.

Applications of fullerene derivatives The fullerene derivatives of the present invention can be suitably used as n-type semiconductor materials, particularly n-type semiconductor materials for photoelectric conversion elements such as organic thin-film solar cells.
The fullerene derivative of the present invention can also be used as an electron transport material for transistors, perovskite solar cells, and the like.

When the fullerene derivative of the present invention is used as an n-type semiconductor material, it is usually used in combination with an organic p-type semiconductor material (organic p-type semiconductor compound).
Examples of the organic p-type semiconductor material include poly-3-hexylthiophene (P3HT), poly-p-phenylene vinylene, poly-alkoxy-p-phenylene vinylene, poly-9,9-dialkylfluorene, and poly-p-. Examples include phenylene vinylene and the like.
Since these are often studied as solar cells and are easily available, it is possible to easily obtain a device having stable performance.
Further, in order to obtain higher conversion efficiency, a donor acceptor type π-conjugated polymer that enables absorption of long wavelength light by narrowing the band gap (low band gap) is effective.
These donor acceptor type π-conjugated polymers have a donor unit and an acceptor unit, and have a structure in which these are arranged alternately.
Examples of the donor unit used here include benzodithiophene, dithienosylol and N-alkylcarbazole, and examples of the acceptor unit include benzothiadiazole, thienothiophene and thiophenpyrroledione.
Specifically, a combination of these units, poly (thieno [3,4-b] thiophene-co-benzo [1,2-b: 4,5-b'] thiophene) (PTBx series), poly (PTBx series), poly ( Polymer compounds such as dithieno [1,2-b: 4,5-b'] [3,2-b: 2', 3'-d] siror-alt- (2,1,3-benzothiadiazole) Is exemplified.
Of these, the preferred one is
(1) Poly ({4,5-bis [(2-ethylhexyl) oxy] benzo [1,2-b: 4,5-b'] dithiophene-2,6-diyl} {3-fluoro-2-[ (2-Ethylhexyl) carbonyl] thieno [3,4-b] thiophendiyl}) (PTB7, structural formula is shown below),
(2) Poly [(4,8-di (2-ethylhexyloxy) benzo [1,2-b: 4,5-b'] dithiophene) -2,6-diyl-alt-((5-octyltiero [3] , 4-c] Pyrrole-4,6-dione) -1,3-diyl) (PBDTTPD, structural formula is shown below),
(3) Poly [(4,4'-bis (2-ethylhexyl) dithieno [3,2-b: 2', 3'-d] siror) -2,6-diyl-alt- (2,1,3) -Benzothiadiazole) -4,7-diyl] (PSBTBT, structural formula is shown below),
(4) Poly [N-9''-heptadecanyl-2,7-carbazole-alto-5,5- (4', 7'-di-2-thienyl-2', 1', 3'-benzothiadiazole) ] (PCDTBT, structural formula is shown below), and (5) Poly [1- (6- {4,8-bis [(2-ethylhexyl) oxy] -6-methylbenzo [1,2-b: 4, 5-b'] dithiophen-2-yl} {3-fluoro-4-methylthieno [3,4-b] thiophen-2-yl} -1-octanone) (PBDTT-CF, structural formula is shown below)
Etc. are exemplified.
Among them, more preferable examples include PTB compounds having a fluorine atom at the 3-position of thieno [3,4-b] thiophene as an acceptor unit, and PBDTTTT-CF and PTB7 are particularly preferable examples. Will be done.

（式中、ｎは繰り返し数を表す。）

（式中、ｎは繰り返し数を表す。）

（式中、ｎは繰り返し数を表す。）

（式中、ｎは繰り返し数を表す。）

（式中、ｎは繰り返し数を表す。）

(In the formula, n represents the number of repetitions.)

(In the formula, n represents the number of repetitions.)

(In the formula, n represents the number of repetitions.)

(In the formula, n represents the number of repetitions.)

(In the formula, n represents the number of repetitions.)

The organic power generation layer prepared by using the fullerene derivative of the present invention as an n-type semiconductor material in combination with an organic p-type semiconductor material can exhibit high conversion efficiency.
Since the fullerene derivative of the present invention exhibits good solubility in various organic solvents, when it is used as an n-type semiconductor material, an organic power generation layer can be prepared by a coating method, and a large area of organic matter can be prepared. The power generation layer is also easy to prepare.

Further, the fullerene derivative of the present invention is a compound having good compatibility with an organic p-type semiconductor material and having an appropriate self-aggregation property. Therefore, the fullerene derivative is used as an n-type semiconductor material (organic n-type semiconductor material) to easily form an organic power generation layer having a bulk junction structure. By using this organic power generation layer, an organic thin-film solar cell or an optical sensor having high conversion efficiency can be obtained.

Therefore, by using the fullerene derivative of the present invention as an n-type semiconductor material, it is possible to manufacture an organic thin-film solar cell having excellent performance at low cost.
Further, as another application of the organic power generation layer containing (or consisting of) the n-type semiconductor material of the present invention, there is an image sensor for a digital camera. In response to the demand for higher functionality (higher definition) of digital cameras, it has been pointed out that existing image sensors made of silicon semiconductors have a problem of lowering sensitivity. On the other hand, it is expected that an image sensor made of an organic material having high light sensitivity will enable high sensitivity and high definition. The material for constructing the light receiving portion of such a sensor is required to absorb light with high sensitivity and generate an electric signal from the light source with high efficiency. In response to such a requirement, the organic power generation layer containing (or consisting of) the n-type semiconductor material of the present invention can efficiently convert visible light into electrical energy, and thus can be used as the image sensor light receiving part material. Can express high function.

n-type semiconductor material The n-type semiconductor material of the present invention comprises the fullerene derivative of the present invention.

Organic power generation layer The organic power generation layer of the present invention contains the fullerene derivative of the present invention as an n-type semiconductor material (n-type semiconductor compound).
The organic power generation layer of the present invention can be an optical conversion layer (photoelectric conversion layer).
Further, the organic power generation layer of the present invention usually contains the organic p-type semiconductor material (organic p-type semiconductor compound) in combination with the fullerene derivative of the present invention, that is, the n-type semiconductor material of the present invention.
The organic power generation layer of the present invention is usually composed of the n-type semiconductor material of the present invention and the organic p-type semiconductor.
In the organic power generation layer of the present invention, preferably, the n-type semiconductor material of the present invention and the organic p-type semiconductor material form a bulk heterojunction structure.

In the organic power generation layer of the present invention, for example, the n-type semiconductor material of the present invention and the organic p-type semiconductor material are dissolved in an organic solvent, and from the obtained solution, a spin coating method, a casting method, a dipping method, an inkjet method, etc. It can be prepared by forming a thin film on a substrate by adopting a known thin film forming method such as a doctor blade method and a screen printing method.

In forming the thin film of the organic power generation layer, the fullerene derivative of the present invention has good compatibility with an organic p-type semiconductor material (preferably P3HT or PTB7) and has appropriate self-aggregation property. An organic power generation layer containing the fullerene derivative of the present invention as an n-type semiconductor material and an organic p-type semiconductor material and having a bulk heterojunction structure can be easily obtained.

Organic thin-film solar cell The organic thin-film solar cell of the present invention includes the organic power generation layer of the present invention described above.
Therefore, the organic thin-film solar cell of the present invention has high conversion efficiency.
The structure of the organic thin-film solar cell is not particularly limited, and can be the same structure as a known organic thin-film solar cell, and the organic thin-film solar cell of the present invention is manufactured according to a known method for manufacturing an organic thin-film solar cell. can.

As an example of an organic thin-film solar cell containing the fullerene derivative, for example, a transparent electrode (cathode), a cathode-side charge transport layer, an organic power generation layer, an anode-side charge transport layer, and a counter electrode (anode) are sequentially laminated on a substrate. An example of a solar cell having a above-mentioned structure can be illustrated. The organic power generation layer is preferably a semiconductor thin film layer (that is, a photoelectric conversion layer) containing an organic p-type semiconductor material and a fullerene derivative of the present invention as an n-type semiconductor material and having a bulk heterojunction structure.
In a solar cell having such a structure, a known material can be appropriately used as a material for each layer other than the organic power generation layer. Specifically, examples of the electrode material include aluminum, gold, silver, copper, indium oxide (ITO), and the like. Examples of the material of the charge transport layer include PFN (poly [9,9-bis (3'-(N, N-dimethylamino) propyl-2,7-fluorene) -alt-2,7- (9,9). -Dioctylfluorene)]) and MoO ₃ (molybdenum oxide) are exemplified.

Optical sensor As described above, the photoelectric conversion layer obtained in the present invention effectively functions as a light receiving unit for an image sensor in a high-performance product of a digital camera. Compared with a conventional optical sensor using a silicon photodiode, overexposure does not occur in a bright place, and a clear image can be obtained even in a dark place. Therefore, it is possible to obtain a higher quality image than that of a conventional camera. The optical sensor is constructed from a silicon substrate, electrodes, a photodetector composed of a photoelectric conversion layer, a color filter, and a microlens. The thickness of the light receiving portion can be about several hundred nm, and can be configured to be a fraction of the thickness of a conventional silicon photodiode.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto.

The symbols and abbreviations in the examples are used with the following meanings. In addition to this, symbols and abbreviations commonly used in the technical field to which the present invention belongs may be used in the present specification.

Synthesis example 1

A chlorobenzene solution (150 mL) of N- (2,6-dimethylphenyl) -glycine (90 mg, 0.5 mmol), benzaldehyde (1 mL), and fullerene (360 mg, 0.5 mmol) was heated to reflux for 48 hours.
The reaction product is concentrated under reduced pressure, and the reaction product is subjected to column chromatography (SiO2, hexane-toluene = 20: 1 to 10: 1).
Further, the product was purified by HPLC (Buckyprep: toluene) to obtain 120 mg (25.4%) of the desired product.
(Purity: 99% or more)

^{1 1} H-NMR (CDCl ₃ ) δ: 2.57 (3H, s), 2.91 (3H, s), 5.00 (1H, d, J = 9.9 Hz), 5.12 (1H, d, J = 9.9 Hz), 6.41 ( 1H, s), 6.82 (1H, d, J = 7.3 Hz), 6.97 (1H, t, J = 7.3 Hz), 7.01 --7.25 (4H, m), 7.50 (2H, bs).
MS (FAB) m / z 944 (M ⁺ ). HRMS calcd for C ₇₆ H ₁₇ N 943.13610; found 943.1340.

Synthesis example 2

A dichlorobenzene solution (300 mL) of N- (2,6-dichlorophenyl) -2-phenylglycine (160 mg, 0.5 mmol), heptanal (1 mL), and fullerene (360 mg, 0.5 mmol) was heated to reflux for 2 weeks.
The reaction product was concentrated under reduced pressure, and the reaction product was purified by column chromatography (SiO2, hexane-toluene = 100: 1 to 20: 1) to obtain 42.0 mg (7.9%) of the desired product.

^{1 1} H-NMR (CDCl ₃ ) δ: 0.81 (3H, t, J = 7.3 Hz), 0.80 ―― 1.60 (8H, m), 2.24 ―― 2.40 (1H, m), 2.60 ―― 2.80 (1H, m), 5.36 (1H, dd, J = 7.3, 4.6 Hz), 6.75 (1H, s), 7.00 --7.32 (5H, m), 7.50 (1H, d, J = 8.0 Hz), 7.63 (1H, bd, J = 7.3) Hz), 7.79 (1H, bd, J = 6.9 Hz).
MS (FAB) m / z 1067 (M ⁺ ). HRMS calcd for C ₈₀ H ₂₃ Cl ₂ N 1067.1208; found 1067.1202.

Synthesis example 3

A dichlorobenzene solution (200 mL) of N- (2,6-methoxyphenyl) -2-phenylglycine (150 mg, 0.52 mmol), heptanal (2 mL), and fullerene (720 mg, 0.5 mmol) was heated under reflux for 4 days.
The reaction product was concentrated under reduced pressure, and the reaction product was purified by column chromatography (SiO2, hexane-toluene = 20: 1 to 5: 1) to obtain 182 mg (33%: amino acid equivalent) of the target product.

^{1 1} H-NMR (CDCl ₃ ) δ: 0.80 (3H, t, J = 7.3 Hz), 1.02 ―― 1.64 (8H, m), 2.16 ―― 2.28 (1H, m), 2.52 ―― 2.64 (1H, m), 3.98 (3H, s), 4.04 (3H, s), 5.36 (1H, dd, J = 6.9, 4.6 Hz), 6.50 (1H, d, J = 8.2 Hz), 6.55 (1H, s), 6.63 (1H, s) d, J = 8.2 Hz), 7.05 --7.30 (4H, m), 7.50 (1H, bs), 8.05 (1H, bs).
MS (FAB) m / z 1060 (M ⁺ ). HRMS calcd for C ₈₂ H ₃₀ NO ₂ (M + 1) 1060.2277; found 1060.2281.

Synthesis example 4

A chlorobenzene solution (300 mL) of N- (2-cyanophenyl) -2-phenylglycine (150 mg, 0.60 mmol), heptanal (1 mL), and fullerene (588 mg, 0.82 mmol) was heated to reflux for 8 days.
The reaction product was concentrated under reduced pressure, and the reaction product was purified by column chromatography (SiO2, hexane-toluene = 20: 1 to 2: 1) to obtain 210 mg (33.6%: amino acid equivalent) of the target product.

^{1 1} H-NMR (CDCl ₃ ) δ: 0.81 (3H, t, J = 7.3 Hz), 1.10 ―― 1.70 (8H, m), 2.16 ―― 2.28 (1H, m), 2.80 ―― 2.92 (1H, m), 5.90 --6.05 (1H, m), 6.41 (1H, s), 7.10 --7.74 (5H, m), 7.44 (1H, t, J = 7.8 Hz), 7.60 (1H, bs), 7.68 (1H, bs), 7.79 (1H, d, J = 7.3 Hz).
MS (FAB) m / z 1025 (M ⁺ ). HRMS calcd for C ₈₁ H ₂₅ N ₂ (M + 1) 1025.2018; found 1025.2014.

Using each fullerene derivative obtained in the synthesis example and the control compounds 1, 2 and 3 described later as n-type semiconductor materials, a solar cell was prepared by the method described later and its function was evaluated.
PTB7 is used as an organic p-type semiconductor material, and PFN (poly [9,9-bis (3'-(N, N-dimethylamino) propyl-2,7-fluorene) -alt-2, is used as a charge transport layer material. 7- (9,9-dioctylfluorene)]) and MoO ₃ (molybdenum oxide) were used, and ITO (indium tin oxide) (cathode) and aluminum (anode) were used as electrodes, respectively.

(1) Preparation of test solar cell A test solar cell was prepared by the following procedure.
1) Pretreatment of the substrate The ITO patterning glass plate was placed in a plasma washer, and the surface of the substrate was washes with the plasma generated while inflowing oxygen gas for 10 minutes.
2) Preparation of PFN thin film (cathode side charge transport layer) ITO pretreated with PFN methanol solution (2% w / v) using ABLE / ASS-301 type spin coating film forming apparatus. A PFN thin film was formed on the glass plate. The film thickness of the formed PFN thin film was about 10 nm.
3) Preparation of organic semiconductor film (organic power generation layer) PTB7 and fullerene derivatives, which were previously dissolved in chlorobenzene using a MIKASA / MS-100 type spin coating film forming apparatus, and diiodooctane (diiodooctane). A solution containing 3% v / v) with respect to chlorobenzene was spin-coated (1000 rpm, 2 minutes) on the PFN thin film to form an organic semiconductor thin film (organic power generation layer) having a thickness of about 90 to 110 nm. A laminate was obtained.
4) Vacuum vapor deposition of anode-side charge transport layer and metal electrode Using a compact high-vacuum vapor deposition device, the laminate prepared above is placed on a mask in the high-vacuum vapor deposition device, and the MoO ₃ layer as the anode-side charge transport layer is used. (10 nm) and an aluminum layer (80 nm) as a metal electrode were sequentially vapor-deposited.

(2) Current measurement by pseudo-sunlight irradiation A source meter, current-voltage measurement software, and a pseudo-sunlight irradiation device were used for current measurement by pseudo-sunlight irradiation.
Each test solar cell produced in (1) above was irradiated with 100 mW of pseudo-sunlight, the generated current and voltage were measured, and the energy conversion efficiency was calculated by the following formula.
Table 1 shows the measurement results of the open circuit voltage. The conversion efficiency is a value obtained by the following formula.
Conversion efficiency _{η (%) = FF (V} oc × J sc / P in) × 100
FF: fill _{factor, V oc:} open circuit _{voltage, J sc:} short-circuit _{current, P in:} incident light intensity (density)
The results are shown in Table 1.

Claims (11)

Equation (1):

[During the ceremony,
X ^1a is a hydrogen atom, a chlorine atom, a bromine atom, an iodine atom, an alkyl group which may have one or more substituents, an alkoxy group which may have one or more substituents, or a cyano. Represents a group
X ^1b represents a chlorine atom, a bromine atom, an iodine atom, a methyl group, a methoxy group, or a cyano group.
R ² represents an aryl group which may have one or more substituents or a heteroaryl group which may have one or more substituents.
R ³ represents a hydrogen atom or an alkyl group, and ring A represents a fullerene ring. ]
Fullerene derivative represented by. The fullerene derivative according to claim 1, wherein X ^1a is a hydrogen atom, a chlorine atom, a bromine atom, an iodine atom, a methyl group, a methoxy group, or a cyano group. The fullerene derivative according to claim 2, wherein X ^1a is a chlorine atom, a bromine atom, an iodine atom, a methyl group, a methoxy group, or a cyano group. The fullerene derivative according to any one of claims 1 to 3 , wherein R ² is an aryl group which may have one or more substituents. The fullerene derivative according to claim 4 , wherein R ² is a phenyl group which may have one or two substituents at the ortho position. Ring A _is a fullerene derivative according to any one of claims 1 to 5 which is a _{C 60} fullerene ring. An n-type semiconductor material containing the fullerene derivative according to any one of claims 1 to 6. The n-type semiconductor material according to claim 7 , which is used for organic thin-film solar cells. An organic power generation layer containing the n-type semiconductor material according to claim 8. The photoelectric conversion element including the organic power generation layer according to claim 9. The photoelectric conversion element according to claim 10 , which is an organic thin-film solar cell.