JP5643572B2 - Fullerene derivative, charge transfer material containing the same, n-type semiconductor material containing the same, and n-type semiconductor thin film containing the same - Google Patents

Description

  The present invention relates to a fullerene derivative, an n-type semiconductor material containing the fullerene derivative, and an n-type semiconductor thin film containing the fullerene derivative.

An organic semiconductor material is an organic material exhibiting the characteristics of a semiconductor. This includes, as with inorganic materials, a p-type semiconductor that conducts holes as carriers and an n-type semiconductor that conducts electrons as carriers. is there. By using an organic semiconductor material, the organic semiconductor material can be reduced in weight and area, and can be made flexible. Applications to batteries, organic thin film transistors (TFTs) and the like are expected. Among organic semiconductor materials, various fullerene derivatives are known as materials exhibiting n-type semiconductivity. However, as described above, it is possible to increase the area of a semiconductor and reduce the manufacturing cost to a practical level. For this, it is necessary to increase the solubility in an organic solvent and to enable the preparation of a semiconductor by a coating method.
Against this background, attempts have been made to introduce various substituents into fullerene for the purpose of enhancing the solubility in organic solvents, and [6,6] -phenyl C61-butyric acid methyl ester ([6,6] -phenyl C61- butyric acid methyl ester (PCBM)) has been reported to produce a field effect transistor (FET) (Non-patent Document 1). Furthermore, the compound design aiming at high functionality has been made, and by introducing a long alkyl group, C60 fullerene (sometimes referred to as C60 in this specification) is highly arranged, and electron mobility exceeding PCBM has been achieved. (Patent Document 1, Non-Patent Document 2). Furthermore, it has been reported that higher electron mobility can be achieved by introducing a long-chain perfluoroalkyl group in place of the alkyl group in order to make the C60 arrangement more robust. Further, it has been reported that this compound not only has high electron mobility (conductivity) but also improves the stability of the fabricated device in the air (Patent Document 2, Non-Patent Document 3). .

JP 2006-60169 A JP 2007-251086 A

Christoph Waldauf et al., Advance Materials, 2003, 15, 2084 Chikamatsu et al., Applied Physics letters, 2005, 87, 203504 Chikamatsu et al., Chemistry of Materials, 2008, 20, 7365

However, since the fluoroalkyl group imparts oil repellency, the fullerene derivative has the following problems in practical use. 1) Since the solubility of the compound in an organic solvent is very poor and the bonding property with other components such as a p-type material and an electrode used at the time of producing the device is low, it is difficult to produce a coating type device. 2) Due to the occurrence of a phase separation phenomenon derived from a fluorine group, the produced coating type device cannot exhibit a stable function in temperature change and long-time use.
Accordingly, the present invention provides an organic n-type semiconductor material having improved solubility in organic solvents and high bonding properties to a p-type semiconductor while maintaining high electron mobility due to the advanced arrangement of fullerene derivatives. The purpose is to do.

  As a result of intensive studies in view of the above problems, the present inventors have found that the above problems can be solved by a fullerene derivative introduced with a long-chain alkyl group in addition to a fluoroalkyl group. The present invention has been completed.

［式中、
Ｒ¹は、ペルフルオロアルキル基、ペルフルオロアルコキシ基、またはペルフルオロポリエーテル基を表し、
Ｒ²は、アルキル基を表し、
ｎは、０〜２の整数を表し、
Ｒ³は、水素、またはアルキル基を表し、
Ｒ⁴は、水素、またはアルキル基を表し、
かつ
Ｒ³およびＲ⁴の少なくとも一方は、炭素数４〜１４のアルキル基である。］
で表されるフラーレン誘導体；
［２］
Ｒ¹が、炭素数４〜１２のペルフルオロアルキル基である前記［１］に記載のフラーレン誘導体；
［３］
ｎが、０である前記［１］または前記［２］に記載のフラーレン誘導体；
［４］
Ｒ³およびＲ⁴が、同一または異なって、炭素数４〜１４のアルキル基である前記［１］〜前記［３］のいずれか１項に記載のフラーレン誘導体；
［５］
前記［１］〜前記［４］のいずれか１項に記載のフラーレン誘導体を含有する電荷移動材料；
［６］
前記［１］〜前記［４］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；
［７］
前記［１］〜前記［４］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型半導体薄膜；
［８］
前記［７］に記載のｎ型半導体薄膜を含有する半導体素子；
［９］
前記［７］に記載のｎ型半導体薄膜を含有する
電界効果型トランジスタ；および
［１０］
前記［７］に記載のｎ型半導体薄膜を含有する
有機薄膜太陽電池
等を提供するものである。 That is, the present invention
[1]
Formula (I)

[Where:
R ¹ represents a perfluoroalkyl group, a perfluoroalkoxy group, or a perfluoropolyether group,
R ² represents an alkyl group,
n represents an integer of 0 to 2,
R ³ represents hydrogen or an alkyl group,
R ⁴ represents hydrogen or an alkyl group,
And at least one of R ³ and R ⁴ are alkyl groups of 4 to 14 carbon atoms. ]
A fullerene derivative represented by:
[2]
The fullerene derivative according to the above [1], wherein R ¹ is a C 4-12 perfluoroalkyl group;
[3]
the fullerene derivative according to the above [1] or [2], wherein n is 0;
[4]
The fullerene derivative according to any one of [1] to [3] above, wherein R ³ and R ⁴ are the same or different and are an alkyl group having 4 to 14 carbon atoms;
[5]
Charge transfer material containing the fullerene derivative according to any one of [1] to [4] above;
[6]
N-type semiconductor material containing the fullerene derivative according to any one of [1] to [4];
[7]
N-type semiconductor thin film containing the fullerene derivative according to any one of [1] to [4];
[8]
A semiconductor element comprising the n-type semiconductor thin film according to [7];
[9]
[10] a field-effect transistor containing the n-type semiconductor thin film according to [7];
An organic thin film solar cell containing the n-type semiconductor thin film according to the above [7] is provided.

The fullerene derivative of the present invention has high solubility in organic solvents and high self-organization.
The charge transfer material or n-type semiconductor material of the present invention enables semiconductor thin film formation by a coating method.
Since the n-type semiconductor thin film of the present invention can be formed by a coating method, the n-type semiconductor thin film can be manufactured at a low cost and in a large area and has excellent bonding properties with a p-type semiconductor.

FIG. 1 is a schematic diagram (Example 7) of a field effect transistor having an n-type semiconductor thin film containing a fullerene derivative of the present invention. FIG. 2 is a photograph (Example 8) of a solar cell produced using the fullerene derivative of the present invention.

<Terminology>
In this specification, “perfluoroalkyl group” means a group in which all hydrogen atoms of an alkyl group are substituted with fluorine atoms, or all hydrogen atoms other than one hydrogen atom at the terminal of the alkyl group are fluorine atoms. Means a substituted group.
In the present specification, the “perfluoroalkoxy group” means a group in which all hydrogen atoms of an alkoxy group are substituted with fluorine atoms, or all hydrogen atoms other than one hydrogen atom at the terminal of the alkoxy group are fluorine atoms. Means a substituted group.
In the present specification, the “perfluoropolyether group” means a monovalent group having a plurality of perfluoroalkylene oxide chains and having a perfluoroalkyl group at the terminal.
In the present specification, the “perfluoroalkylene oxide chain” means an —O-perfluoroalkylene chain or a perfluoroalkylene-O— chain.

<Fullerene derivative>
The fullerene derivative of the present invention is a compound represented by the general formula (I).
Below, the symbol in general formula (I) is demonstrated. In the present specification, unless otherwise specified, the same symbols represent the same meaning.

の部分はＣ６０を表す。 As will be apparent to those skilled in the art, in formula (I)

Represents C60.

The carbon number of the “perfluoroalkyl group” represented by R ¹ is preferably 1-20, more preferably 4-12.
The “perfluoroalkyl group” may be linear or branched, but is preferably linear.

The carbon number of the “perfluoroalkoxy group” represented by R ¹ is preferably 1-20, more preferably 4-12.
The “perfluoroalkoxy group” may be linear or branched, but is preferably linear.

The “perfluoropolyether group” represented by R ¹ is preferably selected from, for example, —C ₃ F ₆ O—, C ₂ F ₄ O—, and —CF ₂ O— having a perfluoroalkyl group at the terminal. C2-C50 perfluoropolyether group which has 1 or more types of repeating units. As the repeating unit, —C ₂ F ₄ O— is preferable. The number of repeating units is preferably 2-20.

Specific examples of the “perfluoropolyether group” include, for example,
(i) F- (CF (-CF 3) -CF 2 -O) m1 -CF (CF 3) - [ wherein, m1 is 1 to 16 integer. ],
(ii) CF ₃ O— (CF (—CF ₃ ) —CF ₂ —O) _m1 — (CF ₂ O) _m2 —CF ₂ — wherein m1 is an integer from 0 to 16 and m2 is from 0 to 20. It is an integer. ],
(iii) CF ₃ —O — ((CF ₂ ) ₂ —O) _m1 — (CF ₂ —O) _m2 —CF ₂ — [wherein m1 is an integer from 1 to 20, and m2 is an integer from 0 to 20. is there. ],
(iv) F — ((CF ₂ ) ₃ —O) _m1 — (CF ₂ ) ₂ — [wherein m1 is an integer of 1 to 16. ],
(v) H- (CF (-CF 3) -CF 2 -O) m1 -CF (CF 3) - [ wherein, m1 is 1 to 16 integer. ],
(vi) H—CF ₂ O— (CF (—CF ₃ ) —CF ₂ —O) _m1 — (CF ₂ O) _m2 —CF ₂ — [wherein m1 is an integer of 0 to 16, m2 is 0 to It is an integer of 20. ],
(vii) H—CF ₂ —O — ((CF ₂ ) ₂ —O) _m1 — (CF ₂ —O) _m2 —CF ₂ — wherein m1 is an integer from 1 to 20 and m2 is from 0 to 20. It is an integer. ],and
(viii) H - ((CF 2) 2 -O) m1 - (CF 2) 2 - [ wherein, m1 is 1 to 16 integer. ],
Etc.
Further, as the “perfluoropolyether group”, specifically, for example,
(ix) F- (CF (—CF ₃ ) —CF ₂ —O) _m1 — [wherein m1 is an integer of 1 to 16. ],
(x) CF ₃ O— (CF (—CF ₃ ) —CF ₂ —O) _m1 — (CF ₂ O) _m2 — wherein m1 is an integer of 0 to 16 and m2 is an integer of 0 to 20. . ],
_{(xi) CF 3 -O - (} (CF 2) 2 -O) m1 - (CF 2 -O) m2 - [ wherein, m1 is an integer of 1 to 20, m2 is an integer of 0 to 20. ],
(xii) F-((CF ₂ ) ₃ —O) _m1 — [wherein m1 is an integer of 1 to 16. ],
(xiii) H- (CF (-CF 3) -CF 2 -O) m1 - [ wherein, m1 is 1 to 16 integer. ],
(xiv) H—CF ₂ O— (CF (—CF ₃ ) —CF ₂ —O) _m1 — (CF ₂ O) _m2 — wherein m1 is an integer from 0 to 16 and m2 is an integer from 0 to 20. It is. ],
(xv) H—CF ₂ —O — ((CF ₂ ) ₂ —O) _m1 — (CF ₂ —O) _m2 — wherein m1 is an integer from 1 to 20 and m2 is an integer from 0 to 20. . ],and
(xvi) H — ((CF ₂ ) ₂ —O) _m1 — [wherein m1 is an integer of 1-16. ],
Etc.

R ¹ is preferably a perfluoroalkyl group having 4 to 12 carbon atoms, for example.
Of these, a perfluoroalkyl group having 4 to 8 carbon atoms, more preferably 4 to 6 carbon atoms, and particularly preferably 4 carbon atoms is preferable.
Among them, preferred is a perfluoroalkyl group having a carbon chain length (that is, the number of carbons in the main chain) of 4 to 8, more preferably a carbon chain length of 4 to 6, and particularly preferably a carbon chain length of 4.

The bonding position of R ¹ on the phenyl group in the general formula (I) is preferably p-position or m-position, more preferably p-position.
The p-position and m-position are shown in the following structural formula.

The carbon number of the “alkyl group” represented by R ² is preferably 1-6.
The “alkyl group” may be linear or branched.
When n is 2, R ² may be the same or different at each occurrence.
n is preferably 0. That is, the phenyl group in the general formula (I) preferably has no substituent other than R ¹ .

The carbon number of the “alkyl group” represented by R ³ is preferably 1-20.
The “alkyl group” may be linear or branched, but is preferably linear.

The carbon number of the “alkyl group” represented by R ⁴ is preferably 1-20.
The “alkyl group” may be linear or branched, but is preferably linear.

At least one of R ³ and R ⁴ is an alkyl group having 4 to 14 carbon atoms (preferably 8 to 14 carbon atoms, more preferably 12 to 14 carbon atoms).
Preferably, both R ³ and R ⁴ are the same or different and are an alkyl group having 4 to 14 carbon atoms.

Particularly preferred as the fullerene derivative of the present invention is, for example,
R ¹ is a perfluoroalkyl group having 4 to 12 carbon atoms (more preferably 4 to 8 carbon atoms, still more preferably 4 to 6 carbon atoms), n is 0,
R ³ is an alkyl group having 1 to 20 carbon atoms,
R ⁴ is a hydrogen atom or an alkyl group having 1 to 20 carbon atoms,
At least one of R ³ and R ⁴ is a compound having an alkyl group having 4 to 14 carbon atoms (preferably 8 to 14 carbon atoms, more preferably 12 to 14 carbon atoms).

As the fullerene derivative of the present invention, it is particularly preferable that, for example,
R ¹ is a linear perfluoroalkyl group having 4 to 8 carbon atoms (preferably 4 to 6 carbon atoms, more preferably 4 carbon atoms),
n is 0;
R ³ is a linear alkyl group having 8 to 14 carbon atoms (preferably 12 to 14 carbon atoms),
R ⁴ is a compound that is a hydrogen atom.

<Method for producing fullerene derivative>
The fullerene derivative of the present invention can be produced, for example, by the method described below or a method analogous thereto.
The symbols in the following reaction schemes are as defined above unless otherwise specified.
In the present specification, unless otherwise specified, “room temperature” refers to about 10 ° C. to about 35 ° C.

（式中、Ｘは脱離基を、Ｃ６０はフラーレンＣ６０を表す。） <Production Method I>
When the fullerene derivative of the present invention is a compound represented by the formula (Ia), the compound can be synthesized, for example, by the following production method or a method analogous thereto.

(In the formula, X represents a leaving group, and C60 represents fullerene C60.)

<Process A>
In step A, compound (3) is obtained by reacting compound (1) with compound (2).
In the formula, examples of the leaving group represented by X include a halogen atom (eg, fluorine, chlorine, bromine, iodine).
Compound (1) is generally used in an amount of 0.1 to 10 mol, preferably 1 to 2 mol, per 1 mol of compound (2).
The reaction is performed without a solvent or in a solvent. Examples of the solvent include dichloromethane, ethanol, methanol, ether, dioxane, dimethoxyethane, DMF, THF, DMSO, NMP and the like. Of these, ethanol, dichloromethane, THF, dioxane and the like are preferable. These solvents may be mixed and used at an appropriate ratio.
The reaction temperature is usually 0 ° C to 120 ° C, preferably room temperature to 60 ° C.
The reaction time is usually 1 hour to 48 hours, preferably 1 to 12 hours.

<Process B>
In step B, compound (4) is obtained by ester hydrolysis of compound (3).
The reaction is carried out in the presence of an acid or alkali, without solvent or in a solvent.
When using an acid, an excess amount is used so that hydrolysis proceeds smoothly, and when using an alkali, usually 0.1 to 10 equivalents, preferably 1 to 2 equivalents are used.
After hydrolysis, the target product is isolated by adjusting the pH with ammonia. The target product is collected by filtration, washed with water to neutrality, and the remaining water is removed under reduced pressure.
Examples of the acid or alkali include concentrated hydrochloric acid, sulfuric acid, sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium carbonate, potassium carbonate and the like. Of these, concentrated hydrochloric acid, sodium hydroxide, potassium carbonate and the like are preferable.
Examples of the solvent include water, dichloromethane, ethanol, methanol, ether, dioxane, dimethoxyethane, DMF, THF, DMSO, NMP and the like. Of these, water, ethanol, dichloromethane, THF, dioxane and the like are preferable. These solvents may be mixed and used at an appropriate ratio.
The reaction temperature is usually 0 ° C. to 150 ° C., preferably room temperature to 100 ° C.
The reaction time is usually 0.1 to 48 hours, preferably 1 to 10 hours.

<Process C>
In Step C, compound (Ia) is obtained by reacting compound (4) with compounds (5) and C60.
Compound (5) can be synthesized according to a known method such as the method described in journal of Fluorine Chemistry, 1991, Vol. 53, page 233.
The amount ratio of the compound (4), the compound (5) and C60 is arbitrary, but from the viewpoint of increasing the yield, the compound (4) and the compound (5) are each usually 0 with respect to 1 mole of C60. .1-10 mol, preferably 0.5-2 mol is used.
The reaction is performed without a solvent or in a solvent.
Examples of the solvent include carbon disulfide, chloroform, dichloroethane, toluene, xylene, chlorobenzene, dichlorobenzene and the like. Of these, chloroform, toluene, chlorobenzene and the like are preferable. These solvents may be mixed and used at an appropriate ratio.
The reaction temperature is about the boiling point of the solvent used. Specifically, it is usually room temperature to 150 ° C, preferably 80 to 120 ° C.
The reaction time is usually 1 to 48 hours, preferably 10 to 24 hours.

  If necessary, the obtained compound (Ia) is purified by, for example, silica gel column chromatography (preferably as hexane-chloroform, hexane-toluene, hexane-carbon disulfide, etc. as a developing solvent) and then HPLC ( The developing solvent is preferably chloroform, toluene, etc.).

（式中、Ｘは脱離基を、Ｃ６０はフラーレンＣ６０を表す。）
式中、Ｘで表される脱離基としては、例えば、ハロゲン原子（例、フッ素、塩素、臭素、ヨウ素）が挙げられる。 <Production Method II>
When the fullerene derivative of the present invention is a compound represented by the following formula (Ib), the compound can be synthesized by, for example, the following production method or a method analogous thereto.

(In the formula, X represents a leaving group, and C60 represents fullerene C60.)
In the formula, examples of the leaving group represented by X include a halogen atom (eg, fluorine, chlorine, bromine, iodine).

<< Steps D to F >>
Compound (9) is obtained by N-methylation of compound (6).
There are various N-methylation methods. Regardless of this method, alkylation with an alkyl halide compound or an alkyl ester of a sulfonic acid in the presence of an alkali can be used as well. However, the method via imination as in this method is excellent in terms of yield.
<Process D>
In Step D, compound (6) is iminized using an imination reagent to obtain compound (7).
As the imination reagent, various aldehydes or aldehyde equivalent compounds can be used. In particular, aminoformaldehyde dialkylacetal provides the desired N-alkylated compound in a high yield under mild conditions. Is preferable.
The imination reagent is generally used in an amount of 0.1 to 10 mol, preferably 1 to 5 mol, per 1 mol of compound (6).
The reaction temperature is usually room temperature to 150 ° C, preferably 50 ° C to 120 ° C.
The reaction time is usually 0.1 to 48 hours, preferably 1 to 15 hours.
This step is performed without a solvent or in a solvent.
Examples of the solvent include dichloromethane, chloroform, ether, THF, dioxane, ethanol, toluene, DMF, DMSO and the like. These solvents may be mixed and used at an appropriate ratio.
From the viewpoint of improving the efficiency of the post-treatment, a reaction without a solvent is preferable.

<Process E>
In Step E, compound (7) is alkylated using an alkylating agent to give compound (8).
As the alkylating agent, various alkylating agents can be used. Examples thereof include dimethyl sulfate, methyl methanesulfonate, methyl trifluorosulfonate, and the like. Of these, dimethyl sulfate, methyl trifluorosulfonate, and the like are preferable.
The alkylating agent is generally used in an amount of 0.1 to 10 mol, preferably 1 to 5 mol, per 1 mol of compound (7).
The reaction temperature is usually 0 ° C to 100 ° C, preferably room temperature to 50 ° C.
The reaction time is usually 0.1 to 48 hours, preferably 1 to 10 hours.
This step is performed without a solvent or in a solvent.
As the solvent, various aprotic solvents can be used. For example, ether, THF, dichloromethane, and toluene are preferable. These solvents may be mixed and used at an appropriate ratio. From the viewpoint of improving the efficiency of the post-treatment, a reaction without a solvent is preferable.

<Process F>
In Step F, compound (8) is hydrolyzed to obtain compound (9).
The hydrolysis is preferably performed in the presence of an acid. The amount of the acid used is usually 0.1 to 100 equivalents, and preferably 1 to 10 equivalents in that the reaction proceeds smoothly. Various acids such as hydrochloric acid, sulfuric acid, nitric acid, chloric acid, and sulfonic acid can be used at various concentrations. Among them, concentrated hydrochloric acid is preferable in terms of reaction efficiency and cost.
The reaction temperature is usually 0 ° C. to 150 ° C., preferably room temperature to 100 ° C.
The reaction time is usually 0.1 to 48 hours, preferably 1 to 10 hours.

<Process G>
In Step G, compound (9) is reacted with compound (5) and C60 to give compound (Ib).
The amount ratio of compound (9), compound (5) and C60 is arbitrary, but from the viewpoint of increasing the yield, compound (4) and compound (5) are usually added to 1 mol of compound (Ia). Each is used in an amount of 0.1 to 10 mol, preferably 0.5 to 2 mol.
The reaction is performed without a solvent or in a solvent.
Examples of the solvent include carbon disulfide, chloroform, dichloroethane, toluene, xylene, chlorobenzene, dichlorobenzene and the like. Of these, chloroform, toluene, chlorobenzene and the like are preferable. These solvents may be mixed and used at an appropriate ratio.
The reaction temperature is about the boiling point of the solvent used. Specifically, it is usually room temperature to 150 ° C, preferably 80 to 120 ° C.
The reaction time is usually 1 to 48 hours, preferably 10 to 24 hours.

  If necessary, the obtained compound (Ib) is purified by, for example, silica gel column chromatography (the developing solvent is preferably hexane-chloroform, hexane-toluene, hexane-carbon disulfide) and then HPLC (development). As the solvent, chloroform and toluene are preferable.

（式中、Ｘは脱離基を、Ｃ６０はフラーレンＣ６０を表す。）
式中、Ｘで表される脱離基としては、例えば、ハロゲン原子（例、フッ素、塩素、臭素、ヨウ素）が挙げられる。 <Production Method III>
When the fullerene derivative of the present invention is a compound represented by the following formula (Ic), the compound can be synthesized, for example, by the following production method or a method analogous thereto.

(In the formula, X represents a leaving group, and C60 represents fullerene C60.)
In the formula, examples of the leaving group represented by X include a halogen atom (eg, fluorine, chlorine, bromine, iodine).

<Process H>
In Step H, the carboxyl group is protected by esterification in order to easily obtain a high-purity compound.
As alcohol used for esterification, general-purpose alcohols, such as methanol, ethanol, propanol, and butanol, are used, for example. Of these, methanol or ethanol is preferred. As the esterification method, for example, a superheated dehydration reaction in the presence of an acid or a method using a condensing agent is used. From the viewpoint of production cost, it is preferable to heat in excess alcohol or toluene using toluenesulfonic acid or concentrated sulfuric acid as a catalyst.
The reaction time is usually 0.1 to 48 hours, preferably 1 to 15 hours.
The reaction temperature is, for example, 100 to 120 ° C. when heating in toluene in the presence of an acid. Moreover, when using a condensing agent, it is 0 degreeC-100 degreeC normally, Preferably it is 0 degreeC-room temperature.
Examples of the condensing agent include dicyclohexylcarbodiimide (DCC), diisopropylcarbodiimide (DIPC), 1-ethyl-3- [3- (dimethylamino) propyl] carbodiimide hydrochloride (EDC · HCl), diphenylphosphoryl azide (DPPA), And thionyl chloride-triethylamine.

<Process I>
In Step I, compound (12) is obtained by reacting compound (1) with compound (11) in the presence of an alkali.
Compound (1) is generally used in an amount of 0.1 to 10 mol, preferably 1 to 2 mol, per 1 mol of compound (11). The usage-amount of an alkali is 0.1-10 mol with respect to 1 mol of compounds (11), and 0.5-2 mol is preferable.
The reaction is performed without a solvent or in a solvent. Examples of the solvent include dichloromethane, ethanol, methanol, ether, dioxane, dimethoxyethane, DMF, THF, DMSO, NMP and the like. Of these, ethanol, dichloromethane, THF, dioxane and the like are preferable. These solvents may be mixed and used at an appropriate ratio.
The reaction temperature is usually 0 ° C to 120 ° C, preferably room temperature to 60 ° C.
The reaction time is usually 1 hour to 48 hours, preferably 1 to 12 hours.

<Process J>
In Step J, compound (13) is obtained by ester hydrolysis of compound (12).
The reaction is carried out in the presence of an acid or alkali, without solvent or in a solvent.
When using an acid, an excess amount is used so that hydrolysis proceeds smoothly, and when using an alkali, usually 0.1 to 10 equivalents, preferably 1 to 2 equivalents are used.
After hydrolysis, the target product is isolated by adjusting the pH with ammonia. After the target product is collected by filtration, it is washed to neutrality, and the remaining water is removed under reduced pressure.
Examples of the acid or alkali include concentrated hydrochloric acid, sulfuric acid, sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium carbonate, potassium carbonate and the like. Of these, concentrated hydrochloric acid, sodium hydroxide, potassium carbonate and the like are preferable.
Examples of the solvent include water, dichloromethane, ethanol, methanol, ether, dioxane, dimethoxyethane, DMF, THF, DMSO, NMP and the like. Of these, water, ethanol, dichloromethane, THF, dioxane and the like are preferable. These solvents may be mixed and used at an appropriate ratio.
The reaction temperature is usually 0 ° C. to 150 ° C., preferably room temperature to 100 ° C.
The reaction time is usually 0.1 to 48 hours, preferably 1 to 10 hours.

<Process K>
In Step K, compound (13) is reacted with compound (5) and C60 to give compound (Ic).
The amount ratio of the compound (5), the compound (13) and C60 is arbitrary, but from the viewpoint of increasing the yield, the compound (5) and the compound (13) are each usually 0 with respect to 1 mole of C60. .1-10 mol, preferably 0.5-2 mol is used.
The reaction is performed without a solvent or in a solvent.
Examples of the solvent include carbon disulfide, chloroform, dichloroethane, toluene, xylene, chlorobenzene, dichlorobenzene and the like. Of these, chloroform, toluene, chlorobenzene and the like are preferable. These solvents may be mixed and used at an appropriate ratio.
The reaction temperature is about the boiling point of the solvent used. Specifically, it is usually room temperature to 150 ° C, preferably 80 to 120 ° C.
The reaction time is usually 1 to 48 hours, preferably 10 to 24 hours.

  If necessary, the obtained compound (Ic) is purified by, for example, silica gel column chromatography (preferably as a developing solvent, hexane-chloroform, hexane-toluene, hexane-carbon disulfide, etc.) and then HPLC ( The developing solvent is preferably chloroform, toluene, etc.).

<Charge transfer material, n-type semiconductor material and n-type semiconductor thin film>
The fullerene derivative of the present invention can be used as a charge transfer material or an n-type semiconductor material.
The fullerene derivative of the present invention is dissolved in an organic solvent, and a thin film is formed on, for example, a p-type doped substrate by a known thin film forming method such as a spin coating method, a casting method, a dipping method, an ink jet method, or a screen printing method. Thus, an n-type semiconductor thin film containing the fullerene derivative of the present invention is obtained.
As the organic solvent, for example, chloroform, dichloromethane, carbon disulfide, toluene, xylene, dichlorobenzene, and trichlorobenzene can be used. The said solvent may be used individually by 1 type, and may be used in combination of 2 or more type.
According to this method, a large-area n-type semiconductor thin film can be obtained at low cost. In addition, the fullerene derivative of the present invention has excellent self-organization and high affinity with a p-type semiconductor (organic p-type conductive material: P3HT (poly-3-hexylthiophene) or the like).

<Application>
The fullerene derivative of the present invention can be used as a charge transfer material or an n-type semiconductor material. The n-type semiconductor thin film obtained from the fullerene derivative of the present invention can be applied to optical and electronic device applications. Specifically, it effectively functions as a field effect capacitor such as an organic thin film transistor (TFT), a photoelectric conversion element such as an organic thin film solar cell, and a light emitting element such as an EL element.
Such a field effect capacitor (eg, organic thin film transistor (TFT)), photoelectric conversion element (eg, organic thin film solar cell), and light emitting element (containing an n-type semiconductor thin film obtained from the fullerene derivative of the present invention) A semiconductor element such as an EL element may be manufactured by a method commonly used in the technical field to which the element belongs.

  FULLERENE DERIVATIVE, CHARGE TRANSFER MATERIAL CONTAINING THE SAME, N-TYPE SEMICONDUCTOR MATERIAL CONTAINING THE SAME, AND N-TYPE SEMICONDUCTOR THIN FILM CONTAINING THE SAME, Field Effect Capacitor such as Organic Thin Film Transistor (TFT), Organic Thin Film Solar Cell It can use for semiconductor elements, such as photoelectric conversion elements.

Hereinafter, the present invention will be described in more detail with reference to examples and the like, but the present invention is not limited thereto.
Purification by HPLC (GPC) was performed using the following apparatus and column.
Apparatus: JASCO LC-9201S
Column: JAIGEL H series (2H-1H is used in two-linkage)
The NMR spectrum shows proton NMR, and was measured with an apparatus: JNM-LA400 (JEOL) using tetramethylsilane as an internal standard. The δ value is expressed in ppm.
Abbreviations used in the following examples and the like have the following significance.
s: singlet br: wide d: doublet t: triplet m: multiplet J: coupling constant Hz: hertz

４−ヨードベンズアルデヒド（4-iodobenzaldehyde）（１ｇ、４．３１ｍｍｏｌ）、ヨウ化ヘプタデカフルオロオクチル（heptadecafluorooctyl iodide）（２．８２ｇ、５．１７ｍｍｏｌ）、銅粉（９０４ｍｇ、１４．２３ｍｍｏｌ）をジメチルスルホキシド１５ｍＬ中、１１０℃で１５時間攪拌した。
反応物をジクロロメタン中に入れ、セライトカラム中を通して無機物を除去した。得られた溶液を水洗して、濃縮後に、シリカゲルクロマトグラフィー（展開溶媒：ｎ−ヘキサン−酢酸エチル（２０：１））で分離して４−ヘプタデカフルオロオクチルベンズアルデヒド（4-heptadecafluorooctylbenzaldehyde）を得た（５８０ｍｇ、２６％）。 Synthesis example 1
<Synthesis of 4-heptadecafluorooctylbenzaldehyde>

4-iodobenzaldehyde (1 g, 4.31 mmol), heptadecafluorooctyl iodide (2.82 g, 5.17 mmol), copper powder (904 mg, 14.23 mmol) in 15 mL of dimethyl sulfoxide The mixture was stirred at 110 ° C. for 15 hours.
The reaction was placed in dichloromethane and removed through a celite column. The obtained solution was washed with water, concentrated, and then separated by silica gel chromatography (developing solvent: n-hexane-ethyl acetate (20: 1)) to obtain 4-heptadecafluorooctylbenzaldehyde. (580 mg, 26%).

Synthesis example 2
<Synthesis of 2- (dodecylamino) acetic acid>
(1) C ₁₂ H ₂₅ NH + BrCH ₂ COOC ₂ H ₅ → C ₁₂ H ₂₅ NHCH ₂ COOC ₂ H ₅
An anhydrous dichloromethane solution (5 mL) of ethyl bromoacetate (0.45 mL, 4.06 mmol) in an anhydrous dichloromethane solution (10 mL) of dodecylamine (1.35 g, 7.3 mmol) and potassium carbonate (355 mg, 2.57 mmol). It was dripped at 0 ° C. The reaction was stirred at room temperature for 24 hours. Inorganic salts are removed by filtration, and the reaction mixture is concentrated and separated by silica gel chromatography (developing solvent: n-hexane-ethyl acetate (3: 1)) to obtain C ₁₂ H ₂₅ NHCH ₂ COOC ₂ H ₅ . Obtained (500 mg, 46%).
(2) C ₁₂ H ₂₅ NHCH ₂ COOC ₂ H ₅ → C ₁₂ H ₂₅ NHCH ₂ COOH
2N sodium hydroxide (22 mL) was added dropwise to a suspension of C ₁₂ H ₂₅ NHCH ₂ COOC ₂ H ₅ (2.9 g) in aqueous ethanol (50 mL), and the mixture was stirred at room temperature. After confirming the disappearance of the raw material with TLC (developing solvent: n-hexane-ethyl acetate (1: 1)), the reaction solution was acidified with 5% hydrochloric acid, and further adjusted to pH 9 with 28% aqueous ammonia. did. The 2- (dodecylamino) acetic acid (C ₁₂ H ₂₅ NHCH ₂ COOH) precipitated here was collected by filtration, washed with water, and then dried under reduced pressure.

Synthesis example 3
<Synthesis of 2-methylamino-1-decanoic acid>
(1) C ₈ H ₁₇ CH (NH ₂ ) COOH → C ₈ H ₁₇ CH (NHCH ₃ ) COOCH ₃
C ₈ H ₁₇ CH (NH ₂ ) COOH (2 g, 11 mmol) and N (CH ₃ ) ₂ CH (OCH ₃ ) ₂ (7.6 g, 64 mmol) were stirred at 100 ° C. for 24 hours.
(2) C ₈ H ₁₇ CH (NHCH ₃ ) COOCH ₃ → C ₈ H ₁₇ CH (NHCH ₃ ) COOH
Excess N (CH ₃ ) ₂ CH (OCH ₃ ) ₂ was distilled off under reduced pressure, methyl trifluoromethanesulfonate (2.45 g, 15 mmol) was added to the remaining reaction mixture, and the mixture was stirred at room temperature for 24 hours. 20 mL of 36% hydrochloric acid was added to the reaction product and stirred at 100 ° C. for 3 hours. The reaction product was washed with 30 mL of ether, 28% aqueous ammonia was added to the remaining aqueous phase, and the precipitated (2-methylamino-1-decanoic acid (C ₈ H ₁₇ CH (NHCH ₃ ) COOH) was collected by filtration and washed with water. And dried under reduced pressure.

Synthesis example 4
<Synthesis of 2-dodecylamino-1-hexadecanoic acid>
(1) C ₁₄ H ₂₉ CHBrCOOH → C ₁₄ H ₂₉ CHBrCOOC ₂ H ₅
C ₁₄ H ₂₉ CHBrCOOH (5.6 g, 17 mmol) and 10 mL of ethanol were heated in toluene in the presence of p-toluenesulfonic acid (10 mg) for 2 days.
(2) C ₁₄ H ₂₉ CHBrCOOC ₂ H ₅ + C ₁₂ H ₂₅ NH ₂ → C ₁₄ H ₂₉ CH (NHC ₁₂ H ₂₅ ) COOC ₂ H ₅
The reaction solution was concentrated under reduced pressure, and 2 equivalents of C ₁₂ H ₂₅ NH ₂ and 1 equivalent of potassium carbonate were added to the remaining reaction product, followed by stirring in dichloromethane at room temperature for 24 hours. The solvent was distilled off under reduced pressure, and the remaining reaction product was separated by silica gel chromatography (developing solvent: n-hexane-ethyl acetate (10: 1)) to obtain C ₁₄ H ₂₉ CH (NHC ₁₂ H ₂₅ ) COOC _2. H ₅ was obtained.
(3) C ₁₄ H ₂₉ CH (NHC ₁₂ H ₂₅ ) COOC ₂ H ₅ → C ₁₄ H ₂₉ CH (NHC ₁₂ H ₂₅ ) COOH
A water-containing ethanol solution of C ₁₄ H ₂₉ CH (NHC ₁₂ H ₂₅ ) COOC ₂ H ₅ and 2 equivalents of sodium hydroxide was stirred at room temperature for 2 days. The reaction solution was acidified with 5% hydrochloric acid, adjusted to pH 9 with 28% aqueous ammonia, and the precipitated 2-dodecylamino-1-hexadecanoic acid (C ₁₄ H ₂₉ CH (NHC ₁₂ H ₂₅ ) COOH) was collected by filtration. Washed with water and dried under reduced pressure.

Synthesis example 5
<Synthesis of 4-Tridecafluorohexylbenzaldehyde>
4-iodobenzaldehyde (745 mg, 3.21 mmol), tridecafluorohexyl iodide (1.72 g, 3.85 mmol), copper powder (673 mg, 10.6 mmol) in 15 mL of dimethyl sulfoxide The mixture was stirred at 110 ° C. for 15 hours.
The reaction was placed in dichloromethane and removed through a celite column. The obtained solution was washed with water, concentrated, and then separated by silica gel chromatography (developing solvent: n-hexane-dichloromethane (10: 1)) to obtain 4-tridecafluorohexylbenzaldehyde (436 mg). 32%).

Synthesis Example 6
<Synthesis of 4-nonafluorohexylbenzaldehyde>
4-iodobenzaldehyde (1 g, 4.31 mmol), nonafluorobutyl iodide (1.76 g, 5.16 mmol), copper powder (904 mg, 14.2 mmol), dimethyl sulfoxide 15 mL The mixture was stirred at 120 ° C. for 20 hours in a stainless steel reaction tube.
The reaction product was passed through a celite column to filter inorganic salts. The resulting reaction solution was extracted with a mixed solution of water and isopropyl ether. The organic phase was separated, dehydrated and concentrated, and then separated by silica gel chromatography (developing solvent: n-hexane-dichloromethane (5: 1)) to obtain 4-nonafluorobutylbenzaldehyde (1. 12g, 80%).

４−ヘプタデカフルオロオクチルベンズアルデヒド
（4-heptadecafluorooctylbenzaldehyde）（５２０ｍｇ、１ｍｍｏｌ）、２−（ドデシルアミノ）酢酸（Ｃ₁₂Ｈ₂₅ＮＨＣＨ₂ＣＯＯＨ）（９７２ｍｇ、４ｍｍｏｌ）、およびＣ６０（１．４４ｇ、２ｍｍｏｌ）を、トルエン（３００ｍＬ）中で２４時間加熱還流した。冷却後、溶媒を溜去し、反応物をシリカゲルカラムクロマトで分離した（展開溶媒：ｎ−ヘキサン−トルエン（５００：１））。さらにＨＰＬＣ（ＧＰＣ：ＣＨＣｌ₃）で精製した。
H-NMR (CDCl3)δ: 0.89 (3H, t, J=8.0Hz), 1.20-1.75 (18H, m), 1.80-2.06 (2H, m), 2.52-2.66 (1H, m), 3.10-3.26 (1H, m), 4.14 (1H, d, J=8.0Hz), 5.12 (1H, d, J=8.0Hz), 5.13 (1H, s), 7.64 (2H, D, J=8.0Hz), 7.98 (2H, bs). Example 1
<Synthesis of Compound 1>

4-heptadecafluorooctylbenzaldehyde (520 mg, 1 mmol), 2- (dodecylamino) acetic acid (C ₁₂ H ₂₅ NHCH ₂ COOH) (972 mg, 4 mmol), and C60 (1.44 g, 2 mmol). , And refluxed in toluene (300 mL) for 24 hours. After cooling, the solvent was distilled off, and the reaction product was separated by silica gel column chromatography (developing solvent: n-hexane-toluene (500: 1)). Further purification by HPLC (GPC: CHCl ₃ ).
H-NMR (CDCl3) δ: 0.89 (3H, t, J = 8.0Hz), 1.20-1.75 (18H, m), 1.80-2.06 (2H, m), 2.52-2.66 (1H, m), 3.10-3.26 (1H, m), 4.14 (1H, d, J = 8.0Hz), 5.12 (1H, d, J = 8.0Hz), 5.13 (1H, s), 7.64 (2H, D, J = 8.0Hz), 7.98 (2H, bs).

４−ヘプタデカフルオロオクチルベンズアルデヒド（５２０ｍｇ、１ｍｍｏｌ）、２−メチルアミノ−１−デカン酸（2-methylamino-1-decanoic acid）（８００ｍｇ、４ｍｍｏｌ）、およびＣ６０（１．４４ｇ、２ｍｍｏｌ）を、トルエン（３００ｍＬ）中で２４時間加熱還流した。冷却後、溶媒を溜去し、反応物をシリカゲルカラムクロマトグラフィーで分離した（展開溶媒：ｎ−ヘキサン−トルエン（２０：１））。さらにＨＰＬＣ（ＧＰＣ：ＣＨＣｌ₃）で精製した。
H-NMR (CDCl3)δ: 0.87 (3H, t, J=8.0Hz), 1.18-1.67 (10H, m), 1.67-1.93 (2H, m), 2.50-2.64 (1H, m), 2.64-2.80 (1H, m), 2.86 (3H, s), 4.91 (1H, d-d, J=8.0, 2.4Hz), 5.58 (1H, s), 7.62 (2H, d, J=8.0Hz), 7.90 (2H, d, J=8.0Hz). Example 2
<Synthesis of Compound 2>

4-Heptadecafluorooctylbenzaldehyde (520 mg, 1 mmol), 2-methylamino-1-decanoic acid (800 mg, 4 mmol), and C60 (1.44 g, 2 mmol) were dissolved in toluene. (300 mL) and refluxed for 24 hours. After cooling, the solvent was distilled off, and the reaction product was separated by silica gel column chromatography (developing solvent: n-hexane-toluene (20: 1)). Further purification by HPLC (GPC: CHCl ₃ ).
H-NMR (CDCl3) δ: 0.87 (3H, t, J = 8.0Hz), 1.18-1.67 (10H, m), 1.67-1.93 (2H, m), 2.50-2.64 (1H, m), 2.64-2.80 (1H, m), 2.86 (3H, s), 4.91 (1H, dd, J = 8.0, 2.4Hz), 5.58 (1H, s), 7.62 (2H, d, J = 8.0Hz), 7.90 (2H, d, J = 8.0Hz).

４−ヘプタデカフルオロオクチルベンズアルデヒド（５２ｍｇ、０．１ｍｍｏｌ）、２−ドデシルアミノ−１−ヘキサデカン酸（2-dodecylamino-1- hexadecanoic acid）（１８０ｍｇ、０．４ｍｍｏｌ）、およびＣ６０（１４４ｍｇ、０．２ｍｍｏｌ）を、トルエン（３０ｍＬ）中で２４時間加熱還流した。冷却後、溶媒を溜去し、反応物をシリカゲルカラムクロマトグラフィーで分離した（展開溶媒：ｎ−ヘキサン）。さらにＨＰＬＣ（ＧＰＣ：ＣＨＣｌ₃）で精製した。
H-NMR (CDCl3)δ: 0.70-0.95 (6H, m), 1.00-2.05 (44H, m), 2.30-2.70 (2H, m), 2.70-3.20 (2H, m), 4.96 (1H, d, J=8.0Hz), 5.63 (1H, s), 7.60 (2H, d, J=8.0Hz), 7.88 (2H, d, J=8.0Hz). Example 3
<Synthesis of Compound 3>

4-Heptadecafluorooctylbenzaldehyde (52 mg, 0.1 mmol), 2-dodecylamino-1-hexadecanoic acid (180 mg, 0.4 mmol), and C60 (144 mg, 0.2 mmol) ) Was heated to reflux in toluene (30 mL) for 24 hours. After cooling, the solvent was distilled off, and the reaction product was separated by silica gel column chromatography (developing solvent: n-hexane). Further purification by HPLC (GPC: CHCl ₃ ).
H-NMR (CDCl3) δ: 0.70-0.95 (6H, m), 1.00-2.05 (44H, m), 2.30-2.70 (2H, m), 2.70-3.20 (2H, m), 4.96 (1H, d, J = 8.0Hz), 5.63 (1H, s), 7.60 (2H, d, J = 8.0Hz), 7.88 (2H, d, J = 8.0Hz).

同様にして４−ヘプタデカフルオロオクチルベンズアルデヒド（２６０ｍｇ、０．５ｍｍｏｌ）、Ｎ−メチルグリシン（３５６ｍｇ、４ｍｍｏｌ）、およびＣ６０（７２０ｍｇ、１ｍｍｏｌ）を、トルエン（１５０ｍＬ）中で２４時間加熱還流した。冷却後、溶媒を溜去し、反応物をシリカゲルカラムクロマトグラフィーで分離した（展開溶媒：ｎ−ヘキサン−トルエン（５：１））。さらにＨＰＬＣ（ＧＰＣ：ＣＨＣｌ₃）で精製した。 Reference example 1
<Synthesis of Compound 4>

Similarly, 4-heptadecafluorooctylbenzaldehyde (260 mg, 0.5 mmol), N-methylglycine (356 mg, 4 mmol), and C60 (720 mg, 1 mmol) were heated to reflux in toluene (150 mL) for 24 hours. After cooling, the solvent was distilled off, and the reaction product was separated by silica gel column chromatography (developing solvent: n-hexane-toluene (5: 1)). Further purification by HPLC (GPC: CHCl ₃ ).

４−トリデカフルオロヘキシルベンズアルデヒド（4-tridecafluorohexylbenzaldehyde）（１０６ｍｇ、０．２５ｍｍｏｌ）、２−（ドデシルアミノ）酢酸（Ｃ₁₂Ｈ₂₅ＮＨＣＨ₂ＣＯＯＨ）（１２２ｍｇ、０．５ｍｍｏｌ）、およびＣ６０（１７５ｍｇ、０．２５ｍｍｏｌ）を、トルエン（1００ｍＬ）中で２４時間加熱還流した。冷却後、溶媒を溜去し、反応物をシリカゲルカラムクロマトグラフィーで分離した（展開溶媒：ｎ−ヘキサン−トルエン（1００：１））。さらにＨＰＬＣ（ＧＰＣ：ＣＨＣｌ₃）で精製した。
H-NMR (CDCl3)δ: 0.89 (3H, t, J=6.8Hz), 1.20-1.60 (17H, m), 1.60-1.75 (1H, m), 1.82-2.05 (2H, m), 2.50-2.62 (1H, m), 3.12-3.23 (1H, m), 4.15 (1H, d, J=9.6Hz), 5.12 (1H, d, J=9.6Hz), 5.13 (1H, s), 7.63 (2H, d, J=8.0Hz), 7.97 (2H, bs). Example 4
<Synthesis of Compound 5>

4-tridecafluorohexylbenzaldehyde (106 mg, 0.25 mmol), 2- (dodecylamino) acetic acid (C ₁₂ H ₂₅ NHCH ₂ COOH) (122 mg, 0.5 mmol), and C60 (175 mg, 0 .25 mmol) was heated to reflux in toluene (100 mL) for 24 hours. After cooling, the solvent was distilled off, and the reaction product was separated by silica gel column chromatography (developing solvent: n-hexane-toluene (100: 1)). Further purification by HPLC (GPC: CHCl ₃ ).
H-NMR (CDCl3) δ: 0.89 (3H, t, J = 6.8Hz), 1.20-1.60 (17H, m), 1.60-1.75 (1H, m), 1.82-2.05 (2H, m), 2.50-2.62 (1H, m), 3.12-3.23 (1H, m), 4.15 (1H, d, J = 9.6Hz), 5.12 (1H, d, J = 9.6Hz), 5.13 (1H, s), 7.63 (2H, d, J = 8.0Hz), 7.97 (2H, bs).

４−ノナフルオロヘキシルベンズアルデヒド（4-nonafluorohexylbenzaldehyde）（８１ｍｇ、０．２５ｍｍｏｌ）、２−（ドデシルアミノ）酢酸（Ｃ₁₂Ｈ₂₅ＮＨＣＨ₂ＣＯＯＨ）（２４３ｍｇ、１ｍｍｏｌ）、およびＣ６０（３６０ｍｇ、０．５ｍｍｏｌ）を、トルエン（１５０ｍＬ）中で２４時間加熱還流した。冷却後、溶媒を溜去し、反応物をシリカゲルカラムクロマトグラフィーで分離した（展開溶媒：ｎ−ヘキサン−トルエン（1000：１））。さらにＨＰＬＣ（ＧＰＣ：ＣＨＣｌ₃）で精製した。
H-NMR (CDCl3)δ: 0.88 (3H, t, J=7.0Hz), 1.10-1.60 (17H, m), 1.60-1.75 (1H, m), 1.80-2.05 (2H, m), 2.55-2.65 (1H, m), 3.10-3.25 (1H, m), 4.15 (1H, d, J=10.2Hz), 5.12 (1H, d, J=10.2Hz), 5.13 (1H, s), 7.64 (2H, d, J=9.0Hz), 7.97 (2H, bs). Example 5
<Synthesis of Compound 6>

4-nonafluorohexylbenzaldehyde (81 mg, 0.25 mmol), 2- (dodecylamino) acetic acid (C ₁₂ H ₂₅ NHCH ₂ COOH) (243 mg, 1 mmol), and C60 (360 mg, 0.5 mmol) Was heated to reflux in toluene (150 mL) for 24 hours. After cooling, the solvent was distilled off, and the reaction product was separated by silica gel column chromatography (developing solvent: n-hexane-toluene (1000: 1)). Further purification by HPLC (GPC: CHCl ₃ ).
H-NMR (CDCl3) δ: 0.88 (3H, t, J = 7.0Hz), 1.10-1.60 (17H, m), 1.60-1.75 (1H, m), 1.80-2.05 (2H, m), 2.55-2.65 (1H, m), 3.10-3.25 (1H, m), 4.15 (1H, d, J = 10.2Hz), 5.12 (1H, d, J = 10.2Hz), 5.13 (1H, s), 7.64 (2H, d, J = 9.0Hz), 7.97 (2H, bs).

Example 6
<Examination of solubility>
In order to confirm the superiority of the fullerene derivative of the present invention over existing compounds, the solubility in chloroform used as a coating solvent during device fabrication was measured. Determination of dissolution was calculated from the total amount of solvent added up to the point when 10 mg of a sample was placed in a transparent glass tube, chloroform was added in small amounts, and no sample remained undissolved. The solubility is as follows.
Compound 1: 4%
Compound 2: 3%
Compound 3: 5%
Compound 4 (Comparative Example): 1%
Compound 5: 3%
Compound 6: 4%
Compound 4 hardly dissolved in toluene, whereas compound 3 dissolved 1%.
From the above, it is suggested that in the fullerene derivative having a pyrrolidine ring, the affinity with other components is improved by introducing a large number of substituents having a long carbon chain length.

以上のデータから、本発明の化合物は、アルキル基の導入により、溶解度が向上していながら、フルオロアルキル基による凝集効果により、比較的高い電子移動度を維持していることが確認された。
ソースメーター（Ｋｅｉｔｈｌｅｙ社、型番２４００）および疑似太陽光照射装置（三永電気製作所、ＸＥＳ−３０１Ｓ）を用いて、ＡＭ１．５条件（光強度１００ｍＷ／ｃｍ²）下、室温で、Ｉ−Ｖ特性を測定し、開放端電圧（Ｖｏｃ）、短絡電流密度（Ｊｓｃ）、曲線因子（ＦＦ）、光電変換効率（η）を求めた。同じＰ_in（光強度）において、Ｖ_oc、Ｊ_sc及びＦＦがいずれも大きな化合物ほど優れた光電変換効率を示す。なお、光電変換効率は下記式によって導出した。 Example 7
<Electron mobility measurement by fabrication of field effect transistor (FET)>
A p-doped Si (silicon) substrate having a 300 nm thick SiO ₂ insulating film was ultrasonically cleaned with toluene, acetone, deionized water, and isopropyl alcohol for 15 minutes each. Thereafter, the substrate was cleaned with ozone for 30 minutes and immersed in a toluene solution of hexamethyldisilazane for 1 hour. Thereafter, the substrate was ultrasonically washed with toluene and acetone for 15 minutes each.
As shown in FIG. 1, gold was vacuum-deposited as an electrode. Further, a 1 wt% o-dichlorobenzene solution of a fullerene derivative was dropped thereon, and the cast film (organic layer) was produced by heating to 70 ° C. with a hot plate. After annealing the obtained device at 150 ° C. for 30 minutes, a source-drain voltage of 80 V was applied under vacuum, and the gate voltage was changed in the range of −20 V to 80 V to obtain FET performance (electron mobility, threshold voltage ( Vth)) was measured. The results are shown in Table 1. In addition, the electron mobility of the compound 4 in Table 1 is a literature value (the said nonpatent literature 3).

From the above data, it was confirmed that the compound of the present invention maintained a relatively high electron mobility due to the aggregation effect of the fluoroalkyl group while the solubility was improved by introduction of the alkyl group.
IV characteristics at room temperature under AM1.5 conditions (light intensity 100 mW / cm ² ) using a source meter (Keithley, Model No. 2400) and a pseudo-sunlight irradiation device (Minaga Electric Works, XES-301S) Were measured, and open circuit voltage (Voc), short circuit current density (Jsc), fill factor (FF), and photoelectric conversion efficiency (η) were determined. In the same P _in (light intensity), a compound having a larger V _oc , J _sc, and FF shows a higher photoelectric conversion efficiency. The photoelectric conversion efficiency was derived from the following formula.

Example 8
<Production of solar cell>
Using compound 1, compound 2, compound 3, compound 4 (comparative example), compound 5 and compound 6, solar cells were fabricated as follows.
1) Substrate pretreatment A mask was attached to an ITO (indium tin oxide) glass plate, and a portion of ITO was etched by immersing in concentrated hydrochloric acid for 15 minutes.
After etching, the ITO glass was taken out from hydrochloric acid, thoroughly washed with water, and then dried in an air atmosphere. Subsequently, the etched ITO glass plate was washed with ultrasonic waves in the order of toluene, acetone, water, and IPA (isopropyl alcohol) for 15 minutes each. Next, the ITO glass plate was placed in a UV ozone cleaner apparatus of Filgen / UV253 and treated in the order of oxygen gas for 6 minutes, ozone gas for 30 minutes to 60 minutes, and nitrogen gas for 2 minutes.
2) Preparation of PEDOT: PSS (polyethylenedioxythiophene / polystyrene sulfonate) thin film ITO glass pretreated with PEDOT: PSS mixed solution using an ABLE / ASS-301 type spin coat film forming apparatus. A PEDOT: PSS thin film was formed on the plate. The spin coating conditions were 500 rpm (5 seconds) and 3000 rpm (3 minutes). The film thickness of PEDOT: PSS obtained here was about 30 nm.
3) Annealing On a hot plate at 135 ° C. in an air atmosphere, the ITO plate on which the PEDOT: PSS thin film was formed in 2) was annealed for 10 minutes. After annealing, it was cooled to room temperature.
4) Preparation of organic semiconductor film P3HT (poly-3-hexylthiophene) and fullerene derivatives (compound 1, compound 2, compound) dissolved in advance using an ABLE / ASS-301 type spin coat method film forming apparatus (manual spinner) 3, a chloroform mixed solution of Compound 4 (Comparative Example), Compound 5, and Compound 6) was spin-coated on a PEDOT: PSS thin film at 2000 rpm for 2 minutes to obtain an organic semiconductor thin film of about 120 to 150 nm.
5) Vacuum deposition of metal electrode Using a small high vacuum deposition apparatus of ULVAC / VPC-260F, the ITO glass substrate on which the laminated film prepared above was formed was placed on the mask in the high vacuum deposition apparatus, and 100 nm of aluminum was deposited. Vapor deposited. A photograph of the device obtained is shown in FIG. 2 ((a) Compound 1, (b) Compound 2, and (c) Compound 4 (Comparative Example)). As is clear from this, in the comparative example (compound 4), since the compatibility with P3HT was poor, phase separation occurred and a good device could not be obtained.
6) Current measurement by simulated sunlight irradiation The generation | occurrence | production of the current was confirmed using the source meter (Keithley, model number 2400), current voltage measurement software, and the simulated sunlight irradiation apparatus (Minaga Electric Manufacturing Co., Ltd., XES-301S).

結果を表２に示す。

The results are shown in Table 2.

Polyfluorinated organic compounds have properties that are essentially difficult to mix with other materials due to the low surface energy inherent to perfluoroalkyls. In order to exhibit a high function as a solar cell, it is necessary that an n-type semiconductor material and a p-type semiconductor material form a so-called bulk heterojunction structure. There, each semiconductor component forms a minute agglomerate and mixes with each other to form a large area pn interface. Furthermore, it is necessary to form a good contact and charge transfer path between each semiconductor component and the electrode, and if this cannot be formed, a large electric resistance is generated in the device.
Compound 4 having only a linear perfluoroalkyl group having a carbon chain length of 8 as a long-chain substituent not only has low solubility, but also has low compatibility with p-type semiconductor components and carrier transport components. As a result, the light-charge separation efficiency decreased, the internal resistance increased, and almost no current flowed. For this reason, the energy conversion efficiency was the lowest value.
In addition, even in compounds 1 to 3 in which a long-chain alkyl group is further introduced to improve the solubility, the affinity with a p-type semiconductor component having a linear perfluoroalkyl group having a carbon chain length of 8 is poor. As in the above, a sufficiently high energy conversion efficiency was not obtained.
Therefore, a compound in which the carbon chain length of perfluoroalkyl was shortened was examined, but no significant improvement was observed with carbon chain length 6 (Compound 5). On the other hand, by setting the carbon chain length to 4 (compound 6), both the short circuit current value and the fill factor (FF) were improved, and a large improvement in energy conversion efficiency was obtained.
From the above, it can be seen that fullerene derivatives having a perfluoroalkyl group having a carbon chain length of 4 or less are particularly excellent as n-type semiconductor materials for solar cells.

Claims (10)

Formula (I)

[Where:
R ¹ represents a perfluoroalkyl group, a perfluoroalkoxy group, or a perfluoropolyether group,
R ² represents an alkyl group,
n represents an integer of 0 to 2,
R ³ represents hydrogen or an alkyl group,
R ⁴ represents hydrogen or an alkyl group,
And at least one of R ³ and R ⁴ are alkyl groups of 4 to 14 carbon atoms. ]
A fullerene derivative represented by: The fullerene derivative according to claim 1, wherein R ¹ is a perfluoroalkyl group having 4 to 12 carbon atoms. The fullerene derivative according to claim 1, wherein n is 0. The fullerene derivative according to any one of claims 1 to 3, wherein R ³ and R ⁴ are the same or different and are alkyl groups having 4 to 14 carbon atoms. The charge transfer material containing the fullerene derivative of any one of Claims 1-4. An n-type semiconductor material containing the fullerene derivative according to claim 1. The n-type semiconductor thin film containing the fullerene derivative of any one of Claims 1-4. A semiconductor device comprising the n-type semiconductor thin film according to claim 7. A field effect transistor comprising the n-type semiconductor thin film according to claim 7. The organic thin-film solar cell containing the n-type semiconductor thin film of Claim 7.

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