JP2016210750A - Fullerene compound, semiconductor device, solar cell and solar cell module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new semiconductor material.SOLUTION: The present invention provides a fullerene compound having a structure represented by formula (I). The present invention provides a fullerene compound having 1-5 structure(s) represented by formula (I) (Cis a carbon atom constituting a fullerene ring; R-Rindependently represent H or a monovalent organic group; R-Rmay be bound to each other to form a ring; a and b independently represent an integer of 1 or more).SELECTED DRAWING: None

Description

  The present invention relates to a fullerene compound, a semiconductor device, a solar cell, and a solar cell module

  Modified fullerenes are known as semiconductor materials and are used in various semiconductor devices such as field effect transistors, electroluminescent elements (LEDs), and photoelectric conversion elements. For example, Patent Document 1 and Patent Document 2 describe fullerene compounds having a silylmethyl group as a substituent.

JP 2009-206470 A JP 2011-184326 A

  In order to improve the performance of semiconductor devices and to expand the applications of semiconductor devices, it is required to expand the range of selectable semiconductor materials.

  An object of the present invention is to provide a new semiconductor material.

（式（Ｉ）中、Ｃ^ｆはフラーレン環を構成する炭素原子を表し、Ｒ^１〜Ｒ^６はそれぞれ独立して水素原子又は１価の有機基を表し、Ｒ^１〜Ｒ^６は互いに結合して環を形成していてもよく、ａ及びｂはそれぞれ１以上の整数を表す。）
［２］前記式（Ｉ）で表わされる構造を１以上５以下有する、［１］に記載のフラーレン化合物。
［３］前記式（Ｉ）中、Ｒ^１及びＲ^２はそれぞれ独立して、置換基を有していてもよい脂肪族基、置換基を有していてもよい芳香族基、置換基を有していてもよいアルコキシ基、又は置換基を有していてもよいアリールオキシ基であることを特徴とする、［１］又は［２］に記載のフラーレン化合物。
［４］前記式（Ｉ）中、Ｒ^３〜Ｒ^６はそれぞれ独立して、水素原子、ハロゲン原子、置換基を有していてもよい脂肪族基又は置換基を有していてもよい芳香族基であることを特徴とする、［１］から［３］の何れかに記載のフラーレン化合物。
［５］ａとｂとの和が２以上３以下であることを特徴とする、［１］から［４］の何れかに記載のフラーレン化合物。
［６］［１］から［５］の何れかに記載のフラーレン化合物を含有する半導体デバイス。
［７］光電変換素子、電界効果トランジスタ又は電界発光素子であることを特徴とする［６］に記載の半導体デバイス。
［８］光電変換素子である［７］に記載の半導体デバイスを備える太陽電池。
［９］［８］に記載の太陽電池を備える太陽電池モジュール。 The gist of the present invention is as follows.
[1] A fullerene compound having a structure represented by the following formula (I).

(In the formula (I), ^{C f} represents a carbon atom constituting the fullerene ^ring, R 1 to R ⁶ each independently represents a hydrogen atom or a monovalent organic ^group, R 1 to R ⁶ are bonded to each other And a and b each represents an integer of 1 or more.)
[2] The fullerene compound according to [1], wherein the structure represented by the formula (I) is 1 to 5 inclusive.
[3] In the formula (I), R ¹ and R ² each independently represents an aliphatic group which may have a substituent, an aromatic group which may have a substituent, or a substituent. The fullerene compound according to [1] or [2], which is an alkoxy group which may have or an aryloxy group which may have a substituent.
[4] In the formula (I), R ^{3 to} R ⁶ are each independently a hydrogen atom, a halogen atom, an aliphatic group which may have a substituent, or an aromatic which may have a substituent. The fullerene compound according to any one of [1] to [3], which is a group.
[5] The fullerene compound according to any one of [1] to [4], wherein the sum of a and b is 2 or more and 3 or less.
[6] A semiconductor device containing the fullerene compound according to any one of [1] to [5].
[7] The semiconductor device according to [6], which is a photoelectric conversion element, a field effect transistor, or an electroluminescence element.
[8] A solar cell comprising the semiconductor device according to [7], which is a photoelectric conversion element.
[9] A solar cell module comprising the solar cell according to [8].

  According to the present invention, a new semiconductor material can be provided.

It is sectional drawing which represents typically the field effect transistor element which concerns on one Embodiment. It is sectional drawing which represents typically the electroluminescent element which concerns on one Embodiment. It is sectional drawing which represents typically the photoelectric conversion element as one Embodiment. It is sectional drawing which represents typically the solar cell as one Embodiment. It is sectional drawing which represents typically the solar cell module as one Embodiment.

  Hereinafter, embodiments of the present invention will be described in detail. The description of the constituent requirements described below is an example (representative example) of the embodiment of the present invention, and the present invention is not limited to these contents unless it exceeds the gist.

<1. Fullerene Compound>
The fullerene compound according to the present invention has a structure represented by the general formula (I).

The fullerene compound refers to a compound containing a fullerene ring, and the fullerene ring refers to a condensed ring structure constituting a closed shell structure in fullerene which is a closed shell structure cluster mainly composed of carbon atoms. The number of atoms constituting the fullerene is not particularly limited and is generally an even number between 60 and 130 in many cases. Examples of fullerenes composed of carbon atoms include C ₆₀ , C ₇₀ , C ₇₆ , C ₇₈ , C ₈₂ , C ₈₄ , C ₉₀ , C ₉₄ or C ₉₆ . In the present embodiment, the fullerene may be a higher-order cluster having more atoms. The fullerene may be a heterofullerene having an atom other than a carbon atom, for example, a boron atom or a nitrogen atom as an atom constituting a closed shell structure. Among these, it is preferred fullerene is _{C 60} or _{C 70. C60} is more preferable in that it is easily available and can exhibit suitable electron acceptability. _C70 is also preferable in that it can exhibit a suitable electron accepting property.

As described above, the fullerene compound according to the present invention has a structure represented by the general formula (I). In the formula (I), C ^f represents the carbon atoms constituting the fullerene ring. That is, the fullerene compound according to the present invention has a substituent (— [CR ³ R ⁴ ] _a —SiR ¹ R ² — [CR ⁵ R ⁶ ] _b —) in the general formula (I) on the fullerene ring. Specifically, in the fullerene compound according to the present invention, a divalent substituent (— [CR ³ R ⁴ ] _a —SiR ¹ R ² — [CR ⁵ R ⁶ ] _b —) in the general formula (I) is used. Both ends of are directly bonded to atoms constituting the closed shell structure of the fullerene ring.

  In the formula (I), a and b each represent an integer of 1 or more. The sum of a and b is 2 or more, on the other hand, preferably 12 or less, more preferably 8 or less, more preferably 4 or less, and particularly preferably 3 or less. a is preferably 2 or less, and more preferably 1. B is preferably 2 or less, more preferably 1.

In the formula (I), R ^{1 to} R ⁶ each independently represents a hydrogen atom or a monovalent organic group. If the fullerene compound has an R ³ 2 or more, each R ³ may be different from each other. The same applies to R ^{4 to} R ⁶ . R ^{1 to} R ⁶ may be bonded to each other to form a ring.

  As the monovalent organic group, a halogen atom, an aliphatic group which may have a substituent, an aromatic group which may have a substituent, an alkoxy group which may have a substituent, or The aryloxy group which may have a substituent is mentioned.

  Examples of the halogen atom include a fluorine atom or a chlorine atom, and a fluorine atom is more preferable.

  As an aliphatic group, a C1-C14 aliphatic hydrocarbon group or a C2-C20 aliphatic heterocyclic group is preferable, and a C1-C6 aliphatic hydrocarbon group is more preferable. Specific examples of the aliphatic hydrocarbon group include an alkyl group, an alkenyl group, and an alkynyl group. As the alkyl group, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an n-hexyl group or an octyl group is preferable, and a methyl group or an ethyl group is more preferable. Examples of the alkenyl group include a vinyl group, an allyl group, and a butenyl group. Examples of the alkynyl group include an ethynyl group, a propargyl group, and a butynyl group.

  As the aromatic group, an aromatic hydrocarbon group having 6 to 20 carbon atoms or an aromatic heterocyclic group having 2 to 20 carbon atoms is preferable, and an aromatic hydrocarbon group having 6 to 10 carbon atoms or 2 to 10 carbon atoms. Aromatic heterocyclic groups are more preferred. Examples of the aromatic hydrocarbon group include a phenyl group, a naphthyl group, and an anthracenyl group, and a phenyl group or a naphthyl group is more preferable. Examples of the aromatic heterocyclic group include a pyridyl group, a thienyl group, a furyl group, and a pyrrolyl group.

  As an alkoxy group, a C1-C14 alkoxy group is preferable and a C1-C6 alkoxy group is more preferable. Examples of the alkoxy group include a methoxy group, an ethoxy group, an i-propoxy group, an n-hexyloxy group, and a 2-ethylhexyloxy group.

  As an example of the aryloxy group, an aryloxy group having 2 to 20 carbon atoms is preferable, and an aryloxy group having 2 to 10 carbon atoms is more preferable. Examples of the aryloxy group include a phenoxy group or a naphthoxy group.

  Although there is no limitation in particular as a substituent which these substituents may have, a halogen atom, a C1-C14 alkyl group, a C1-C14 fluorinated alkyl group, and a C1-C14 alkoxy group Is preferred. More preferably, it is a fluorine atom or a C1-C14 alkoxy group as a substituent. Examples of the alkoxy group having 1 to 14 carbon atoms include a methoxy group, an ethoxy group, an i-propoxy group, an n-hexyloxy group, and a 2-ethylhexyloxy group. Specific examples of the aromatic group that may have a substituent include 2- (2'-ethylhexyloxy) phenyl group. Although there is no limitation in the number of the substituents which may have, 1 or more and 3 or less are preferable and 1 is more preferable. When it has a plurality of substituents, the type of each substituent may be different, but is preferably the same.

In the formula (I), R ¹ and R ² each independently have an aliphatic group which may have a substituent, an aromatic group which may have a substituent, or a substituent. It is preferably an alkoxy group which may be substituted, or an aryloxy group which may have a substituent, and an aliphatic hydrocarbon group which may have a substituent or an aromatic which may have a substituent More preferably, it is a group. R ¹ and R ² may be the same substituent.

In formula (I), R ^{3 to} R ⁶ are each independently a hydrogen atom, a halogen atom, an aliphatic group which may have a substituent, or an aromatic group which may have a substituent. It is preferably a hydrogen atom, a halogen atom or an aliphatic hydrocarbon group which may have a substituent, and more preferably a hydrogen atom or a halogen atom. R ^{3 to} R ⁶ may be the same substituent.

  The number of structures represented by the formula (I) of the fullerene compound according to the present invention is not particularly limited, but is preferably 1 or more and 5 or less, and particularly preferably, the fullerene compound is represented by the formula (I). It has only one structure.

Substituents other than the substituent in formula (I) may be bonded to the fullerene ring. Examples of the substituent that may be further bonded to the fullerene ring include a methano group that may have a substituent, an indanediyl group that may have a substituent, or a substituent. A good silylmethyl group and the like can be mentioned. Examples of the fullerene ring having a methano group, a phenyl C _61-butyric acid methyl ester (PCBM) and dihydrotestosterone methanofullerene like are known. As an example of a fullerene ring having an indandiyl group, a fullerene indenebis adduct (ICBA) and the like are known. Further, dimethylphenylsilylmethylfullerene (SIMEF) is known as an example of a fullerene ring having a silylmethyl group.

A more specific example of the fullerene compound according to the present invention is a fullerene compound represented by the following formula (II).

In the formula (II), R ^{1 to} R ⁶ , a and b are the same as those in the formula (I). In the formula (II), FLN represents a fullerene which may have a substituent other than the substituent in the structure represented by the formula (I). The example of fullerene and the example of the substituent which may have are as above-mentioned.

  In formula (II), n is not particularly limited, but is preferably an integer of 1 to 5, and n is 1 in that the LUMO energy level of the fullerene compound can be appropriately adjusted. Is preferred.

  The fullerene compound according to the present invention can be used in place of a known fullerene compound. For example, a layer formed using a fullerene compound according to one embodiment exhibits n-type semiconductor characteristics. For this reason, such a fullerene compound can be used as a material of the semiconductor layer with which a semiconductor device is provided. For example, the fullerene compound which concerns on one Embodiment can be used as an n-type semiconductor material for active layers with which a photoelectric conversion element is provided. Moreover, the fullerene compound which concerns on one Embodiment can be used as a material for electron extraction layers with which a photoelectric conversion element is provided.

  By using the fullerene compound according to the present invention, a semiconductor device having good electrical characteristics can be produced. The reason is considered that the solubility of the fullerene compound according to the present invention is improved by having a cyclic substituent containing a silicon atom, and as a result, a high-quality film containing the fullerene compound according to the present invention can be formed. . A crystal of a fullerene compound having a silylmethyl group (for example, 1,4-bis (trimethylsilylmethyl) [60] fullerene) may have a structure advantageous for charge transport in which a fullerene site and a silylmethyl group are assembled. Are known. The fullerene compound according to the present invention has a steric hindrance because the substituent containing a silicon atom has a cyclic structure as compared with such a conventional compound, and has a structure advantageous for such charge transport. It will be easier.

(Fullerene compound-containing layer forming composition)

  The composition containing the fullerene compound according to the present invention and a solvent can be used as a composition for forming a layer containing the fullerene compound according to the present invention. Specifically, a layer containing the fullerene compound according to the present invention can be formed by applying and drying such a composition. This composition may further contain an additive, but preferably the main components of the composition are the fullerene compound and the solvent according to the present invention.

  Examples of the solvent include aliphatic hydrocarbons such as hexane, heptane, octane, isooctane, nonane or decane; aromatic hydrocarbons such as toluene, xylene, mesitylene, cyclohexylbenzene, chlorobenzene, or orthodichlorobenzene; cyclopentane, Cycloaliphatic hydrocarbons such as cyclohexane, methylcyclohexane, cycloheptane, cyclooctane, tetralin or decalin; lower alcohols such as methanol, ethanol or propanol; aliphatic ketones such as acetone, methyl ethyl ketone, cyclopentanone or cyclohexanone; Aromatic ketones such as acetophenone or propiophenone; esters such as ethyl acetate, butyl acetate or methyl lactate; chloroform, methylene chloride, dichloroe Emissions, halogenated hydrocarbons such as trichloroethane or trichlorethylene; ethers such as ethyl ether and tetrahydrofuran or dioxane; or an amide such as dimethylformamide or dimethylacetamide, and the like. Carbon disulfide can also be used.

  The concentration of the fullerene compound contained in the composition is not particularly limited, and can be appropriately selected so that a layer having an appropriate thickness is formed. The concentration of the fullerene compound is preferably 0.1% by weight or more, more preferably 0.5% by weight or more, while preferably 60% by weight or less, so that the coating film formation proceeds smoothly. Preferably it is 45 weight% or less.

<2. Method for producing fullerene compound>
Although the manufacturing method of the fullerene compound which concerns on this invention is not specifically limited, The fullerene compound which concerns on this invention can be manufactured using the compound which has a structure represented by general formula (Ia) as follows. That is, the fullerene compound according to the present invention can be produced by converting the structure represented by the formula (Ia) into the structure represented by the formula (I) by a transfer reaction.

Similarly C ^f in the formula (I) represents a carbon atom constituting the fullerene ring. In the formula (Ia), X is any leaving group, for example, a silylmethyl group. In one example, one of the substituents represented by formula (Ia) is bonded to the 1-position of the 6-membered ring constituting the fullerene ring, and the other is bonded to the 2-position or 4-position of the same 6-membered ring. When a is 1,-[CR ³ R ⁴ ] _a-1- represents a direct bond, and when b is 1,-[CR ⁵ R ⁶ ] _b-1- represents a direct bond.

For example, a compound having a structure represented by formula (I) can be produced by heating a compound having a structure represented by formula (Ia). More specifically, the fullerene compound represented by the formula (II) can be produced by heating the fullerene compound represented by the formula (IIa).

In the formula (IIa), R ⁷ and R ⁸ are a hydrogen atom or a monovalent organic group, and specific examples thereof include the same substituents as those described above for R ¹ and R ² . R ^{9 to} R ¹² are also a hydrogen atom or a monovalent organic group, and specific examples thereof include the same substituents as those described above for R ^{3 to} R ⁶ . R ^{7 to} R ¹² may be bonded to each other to form a ring. a and b are the same as in formula (I).

In the formula (IIa), one substituent — [CR ³ R ⁴ ] _a-1 CR ³ R ⁴ SiR ¹ R ² CHR ⁵ R ⁶ is bonded to the 1-position of the six-membered ring constituting the fullerene ring, and the other Substituent-[CR ⁵ R ⁶ ] _b-1 CR ⁹ R ¹⁰ SiR ⁷ R ⁸ CHR ¹¹ R ¹² is bonded to the 2- or 4-position of the same 6-membered ring.

Such a compound can be produced according to JP 2009-206470 A. As an example of a specific production method, a nucleophilic reagent such as ClMg [CR ³ R ⁴ ] _a-1 CR ³ R ⁴ SiR ¹ R ² CHR ⁵ R ^{6 is} allowed to act on fullerene, and then potassium t-butoxide or the like is used. A method of treating with a base and causing an electrophilic reagent such as Cl [CR ⁵ R ⁶ ] _b-1 CR ⁹ R ¹⁰ SiR ⁷ R ⁸ CHR ¹¹ R ¹² to act on may be mentioned. From the viewpoint of facilitating purification, the substituent-[CR ³ R ⁴ ] _a-1 CR ³ R ⁴ SiR ¹ R ² CHR ⁵ R ⁶ is substituted with the substituent-[CR ⁵ R ⁶ ] _b-1 CR ⁹ R ^10. The substituent is preferably the same as SiR ⁷ R ⁸ CHR ¹¹ R ¹² .

  The heating temperature for heating the compound having the substituent represented by the formula (Ia) or (IIa) on the fullerene ring is not particularly limited, but is 200 ° C. or more for promoting the cyclization reaction. Preferably, it is 250 ° C. or higher, more preferably 300 ° C. or higher, and on the other hand, preferably 500 ° C. or lower, and 400 ° C. or lower to suppress the decomposition reaction. More preferably, it is particularly preferably 350 ° C. or lower.

  The heating time is preferably 1 minute or more for promoting the cyclization reaction, more preferably 5 minutes or more, particularly preferably 10 minutes or more, while for suppressing the decomposition reaction. It is preferably 24 hours or less, more preferably 12 hours or less, and particularly preferably 6 hours or less.

  The fullerene compound according to the present invention can also be produced by a method other than the above. For example, the fullerene compound according to the present invention can be produced by a reaction between the compound represented by the formula (III) and fullerene.

  The fullerene compound according to the present invention can be produced, for example, by a nucleophilic substitution reaction of fullerene with respect to the compound represented by the formula (III). Specific examples include a method of reacting a compound represented by formula (III), fullerene, and a base. For example, according to the present invention, the fullerene and the base are stirred in a solvent (first stirring), and then the compound represented by the formula (III) is added and further stirred (second stirring). A fullerene compound can be produced.

In formula ^{(III), R 1 ~R 6} , a and b have the same meanings as ^R 1 ^{to R} 6, a and b in the formula (I). Further, in the equation (III), ^{X 1} and ^{X 2} represents a leaving group. There is no particular limitation on the leaving group, and for example, a leaving group usually used in a nucleophilic substitution reaction can be used. A preferred example of the leaving group is a halogen atom, and it is particularly preferred that the leaving group is an iodine atom.

  Although there is no special restriction | limiting in the base used by this reaction, For example, potassium carbonate, sodium methoxide, sodium thiomethoxide, etc. are mentioned. Moreover, there is no special restriction | limiting also in the solvent used by this reaction. From the viewpoint of solubility, the solvent is preferably a polar solvent. For example, acetonitrile, dimethylfuran, dimethyl sulfoxide, N-methylpyrrolidone, etc. are mentioned.

  This reaction may be performed at room temperature or by heating. The time for performing the first stirring and the time for performing the second stirring are not particularly limited, but each is preferably 1 day or longer, and particularly preferably 2 days or longer.

<3. Semiconductor Device>
Below, the semiconductor device using the fullerene compound which concerns on this invention is demonstrated. The semiconductor device according to the present invention contains the fullerene compound according to the present invention, more specifically, a component containing the fullerene compound according to the present invention, for example, a layer containing the fullerene compound according to the present invention. Have. A semiconductor device according to an embodiment includes a pair of electrodes and a semiconductor layer disposed between the pair of electrodes. In this semiconductor device, the semiconductor layer includes the fullerene compound according to the present invention, or a further layer including the fullerene compound according to the present invention is provided.

  In this specification, a semiconductor device refers to an electronic device provided with a semiconductor layer containing a semiconductor compound. An electronic device is a device that has two or more electrodes and controls the current flowing between the electrodes or the voltage generated by electricity, light, magnetism, or a chemical substance, or the voltage applied between the electrodes or A device that generates light, an electric field, a magnetic field, or the like by an electric current. Specific examples include an element that controls current or voltage by applying voltage or current, an element that controls voltage or current by applying a magnetic field, or an element that controls voltage or current by applying a chemical substance. Specific examples of control include rectification, switching, amplification, or oscillation.

In this specification, “semiconductor” is defined by the magnitude of carrier mobility in a solid state. As is well known, the carrier mobility is an index indicating how fast (or many) charges (electrons or holes) can be transferred. Specifically, the “semiconductor” in this specification preferably has a carrier mobility at room temperature of preferably 1.0 × 10 ⁻⁶ cm ² / V · s or more, more preferably 1.0 × 10 ⁻⁵ cm ² / V · s or more. More preferably, it is 5.0 × 10 ⁻⁵ cm ² / V · s or more, and particularly preferably 1.0 × 10 ⁻⁴ cm ² / V · s or more. The carrier mobility can be measured, for example, by measuring the IV characteristics of the field effect transistor or the time-of-flight method.

  Examples of semiconductor devices include resistors, rectifiers (diodes), switching elements (transistors, thyristors), amplifier elements (transistors), memory elements, chemical sensors, etc., or devices obtained by combining or integrating these elements Is mentioned. Further, as a further example of a semiconductor device, there is an optical element. In the optical element, a photodiode or a phototransistor that generates a photocurrent, an electroluminescent element that emits light by applying an electric field, or photoelectric conversion that generates an electromotive force by light. An element or a solar cell is included.

  As a more specific example of the semiconductor device, S.A. M.M. Examples include those described in Sze, Physics of Semiconductor Devices, 2nd Edition (Wiley Interscience 1981). Especially, as a preferable example of the semiconductor device which concerns on one Embodiment, a field effect transistor element (FET), an electroluminescent element (LED), a photoelectric conversion element, or a solar cell is mentioned.

  The kind of electrode is not specifically limited. Depending on the type of semiconductor device, an electrode can be manufactured using an appropriate material. Specific examples of electrodes will be described later with respect to some semiconductor devices.

  A semiconductor compound refers to a compound that becomes a material of a semiconductor. The kind of semiconductor compound is not particularly limited. For example, the semiconductor layer may contain the fullerene compound according to the present invention as a semiconductor compound. Further, the semiconductor layer may contain a p-type semiconductor compound, may contain an n-type semiconductor compound, or may contain both of them. The semiconductor layer may contain a perovskite semiconductor compound.

  Examples of the p-type semiconductor compound include polymer semiconductor compounds such as conjugated copolymer semiconductors such as polythiophene, polyfluorene, polyphenylene vinylene, polythienylene vinylene, polyacetylene, and polyaniline. Further, as a p-type semiconductor compound, condensed aromatic hydrocarbons such as naphthacene, pentacene or pyrene; oligothiophenes containing 4 or more thiophene rings such as α-sexithiophene; thiophene ring, benzene ring, fluorene ring, naphthalene ring , An anthracene ring, a thiazole ring, a thiadiazole ring, and a benzothiazole ring, and a total of four or more connected; a phthalocyanine compound and a metal complex thereof, or a porphyrin compound such as tetrabenzoporphyrin and a metal complex thereof And low molecular semiconductor compounds such as macrocyclic compounds. Single-walled carbon nanotubes or graphene can also be used as the p-type semiconductor compound.

  As the n-type semiconductor compound, the fullerene compound according to the present invention can be used. Examples of other n-type semiconductor compounds include fullerene compounds, quinolinol derivative metal complexes such as 8-hydroxyquinoline aluminum, condensed ring tetracarboxylic acid diimides such as naphthalene tetracarboxylic acid diimide or perylene tetracarboxylic acid diimide, and perylene diimide derivatives. , Terpyridine metal complex, tropolone metal complex, flavonol metal complex, perinone derivative, benzimidazole derivative, benzoxazole derivative, thiazole derivative, benzthiazole derivative, benzothiadiazole derivative, oxadiazole derivative, thiadiazole derivative, triazole derivative, aldazine derivative, bisstyryl Derivatives, pyrazine derivatives, phenanthroline derivatives, quinoxaline derivatives, benzoquinoline derivatives, bipyridine derivatives, Emissions derivatives, anthracene, pyrene, total fluoride condensed polycyclic aromatic hydrocarbons such as naphthacene or pentacene, and graphene or n-type polymers and the like.

A perovskite semiconductor compound refers to a semiconductor compound having a perovskite structure. The perovskite semiconductor compound is not particularly limited, and can be selected from, for example, those listed in Galasso et al. Structure and Properties of Inorganic Solids, Chapter 7-Perovskite type and related structures. For example, examples of the perovskite compound include those represented by the general formula AMX ₃ and those represented by the general formula A ₂ MX ₄ . Here, M represents a divalent cation, A represents a monovalent cation, and X represents a monovalent anion.

  As the semiconductor compound contained in the semiconductor layer, an appropriate compound can be selected according to the type of the semiconductor device. Specific examples of semiconductor compounds will be described later with respect to several semiconductor devices.

  The thickness of the semiconductor layer is not particularly limited, and can be appropriately selected according to the use of the semiconductor layer. As an example, the thickness of the semiconductor layer may be not less than 0.5 nm and not more than 500 nm.

  In addition to the semiconductor compound, other compounds may be added to the semiconductor layer. In this case, the ratio of the semiconductor compound in the semiconductor layer is preferably 50% by mass or more, more preferably 70% by mass or more, and more preferably 90% by mass so that the semiconductor characteristics of the semiconductor layer are well exhibited. % Or more. The semiconductor layer may have a stacked structure including a plurality of layers containing different materials or having different components.

  The method for forming the semiconductor layer is not particularly limited, and any method can be used. Specific examples include a coating method for forming a semiconductor layer by coating a coating solution containing a semiconductor compound or a semiconductor compound precursor, and a vapor deposition method for depositing a semiconductor compound. It is preferable to use a coating method because a semiconductor layer can be easily formed.

  The semiconductor compound precursor refers to a material that can be converted into a semiconductor compound after coating a coating solution. A specific example is a semiconductor compound precursor that can be converted into a semiconductor compound by heating. For example, by heating a film obtained by applying a coating solution, a semiconductor compound precursor can be converted into a semiconductor compound to form a semiconductor layer containing the semiconductor compound.

  Specific examples of the semiconductor compound precursor include a compound represented by the formula (2) described below and / or a formula (described later) which can be converted into a perovskite semiconductor compound represented by the formula (1) described below by heating. Examples of the compound represented by 3) include metal halides and alkylammonium salt halides. Moreover, the bicycloporphyrin compound etc. which can be converted into the porphyrin compound which is a p-type semiconductor compound by heating are mentioned.

  The coating liquid used for the coating method can be prepared by dissolving a semiconductor compound or a semiconductor compound precursor in a solvent. The solvent is not particularly limited as long as the semiconductor compound or the semiconductor compound precursor is dissolved. As a solvent, the thing similar to what was mentioned above as a solvent which the composition for forming the layer containing the fullerene compound concerning this invention contains can be used.

  When a perovskite semiconductor compound is used, as a solvent for the coating solution, Brandrup, J. et al. The solubility parameter (SP value) described in et al. “Polymer Handbook, 4th Ed.” Is preferably 9 or more, and more preferably 10 or more. Examples thereof include N, N-dimethylformamide, N, N-dimethylacetamide, N, N-diethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide, pyridine, and γ-butyrolactone. As the solvent, a mixed solvent of two or more kinds of solvents may be used. Even when a mixed solvent is used, the solubility parameter of at least one of the mixed solvents is preferably 10 or more.

  Although any method can be used as a coating method of the coating solution, for example, spin coating method, ink jet method, doctor blade method, drop casting method, reverse roll coating method, gravure coating method, kiss coating method, roll brush method, Examples thereof include a spray coating method, an air knife coating method, a wire barber coating method, a pipe doctor method, an impregnation / coating method, and a curtain coating method.

  A semiconductor layer can be formed by performing drying after applying the coating solution and performing a process of converting the semiconductor compound precursor into a semiconductor compound as necessary. The drying method is not particularly limited, and for example, heat drying may be performed.

  Hereinafter, a field effect transistor element, an electroluminescence element, a photoelectric conversion element, and a solar cell will be described in detail as examples of the semiconductor device according to the present invention.

<4. Field Effect Transistor (FET)>
A field effect transistor (FET) device according to the present invention includes a semiconductor layer, a pair of electrodes, a source electrode and a drain electrode, and a gate electrode.

  Hereinafter, the FET element according to an embodiment will be described in detail. FIG. 1 is a diagram schematically showing a structural example of an FET element according to the present invention. In FIG. 1, 51 is a semiconductor layer, 52 is an insulator layer, 53 and 54 are source and drain electrodes, 55 is a gate electrode, and 56 is a substrate. The semiconductor layer 51 contains the fullerene compound according to the present invention as a semiconductor compound. However, in another embodiment, the FET element may have a layer containing the fullerene compound according to the present invention, which is different from the semiconductor layer 51 serving as a channel between the source electrode 53 and the drain electrode 54. .

  Although FIGS. 1A to 1D show FET elements having different structures, each of them shows a structure example of an FET element according to the present invention. There is no particular limitation on these constituent members constituting the FET element and the manufacturing method thereof, and well-known techniques can be used. For example, techniques described in publicly known documents such as International Publication No. 2013/180230 can be used.

  In the FET element according to one embodiment, the semiconductor layer 51 is produced by forming a semiconductor film on the substrate 56 directly or via another layer. The film thickness of the semiconductor layer 51 is not limited. For example, in the case of a horizontal field effect transistor element, the element characteristics do not depend on the film thickness of the semiconductor layer 51 as long as the film thickness is equal to or greater than a predetermined film thickness. However, since the leakage current often increases when the film thickness becomes too thick, the film thickness of the semiconductor layer is preferably 0.5 nm or more, more preferably 10 nm or more, and preferably 1 μm from the viewpoint of cost. Hereinafter, it is more preferably 200 nm or less.

As the characteristics of the semiconductor layer 51, the carrier mobility at room temperature is preferably 1.0 × 10 ⁻⁶ cm ² / V · s or more, more preferably 1.0 × 10 ⁻⁵ cm ² / V · s or more, more preferably 5. 0 × 10 ⁻⁵ cm ² / V · s or more, particularly preferably 1.0 × 10 ⁻⁴ cm ² / V · s or more.

<5. Electroluminescent device (LED)>
The electroluminescent element (LED) according to the present invention includes a pair of electrodes, an anode and a cathode, and a light emitting layer disposed between the electrodes. An electroluminescent element is a self-luminous element that utilizes the principle that a fluorescent substance emits light by recombination energy between holes injected from an anode and electrons injected from a cathode when an electric field is applied. In one embodiment, the light emitting layer contains the fullerene compound according to the present invention. However, in another embodiment, the electroluminescent element according to the present invention may have a layer containing the fullerene compound according to the present invention, which is different from the light emitting layer. For example, the electron injection layer or the electron transport layer may be a layer containing the fullerene compound according to the present invention.

  FIG. 2 is a cross-sectional view schematically showing one embodiment of the electroluminescent element according to the present invention. In FIG. 2, reference numeral 31 is a base material, 32 is an anode, 33 is a hole injection layer, 34 is a hole transport layer, 35 is a light emitting layer, 36 is an electron transport layer, 37 is an electron injection layer, 38 is a cathode, 39 Indicates an electroluminescent element. Note that the electroluminescent element does not need to have all of these constituent members, and the necessary constituent members can be arbitrarily selected. For example, the hole injection layer 33, the hole transport layer 34, the electron transport layer 36, and the electron injection layer 37 are not necessarily provided. There are no particular restrictions on these constituent members constituting the electroluminescent element and the manufacturing method thereof, and well-known techniques can be used. For example, a technique described in a publicly known document such as Japanese Patent Application Laid-Open No. 2015-032606 can be used.

There is no restriction | limiting in the formation method of the light emitting layer 35. FIG. For example, a wet film formation method or a dry film formation method can be used. In addition, for the purpose of improving the light emission efficiency of the device, changing the emission color, and improving the drive life of the device, the host material emits light by doping with another compound such as a fluorescent dye or a phosphorescent metal complex. Layer 35 may be made. For example, by doping with a fluorescent dye,
1) Improvement of luminous efficiency by high-efficiency fluorescent dyes 2) Variable emission wavelength by selection of fluorescent dyes 3) Use of fluorescent dyes that cause concentration quenching 4) Use of fluorescent dyes with poor thin film properties 5) It is expected that driving stability is improved by eliminating charge traps.

  In addition, mixing a hole transport material in the light emitting layer 35 is also effective for the purpose of improving the driving stability of the device. The amount of the hole transport material mixed in the light emitting layer 35 is preferably in the range of 5 to 50% by mass.

  The thickness of the light emitting layer 35 is not limited, and is preferably 3 nm or more, more preferably 10 nm or more, preferably 300 nm or less, more preferably so that the amount of light emission can be secured while satisfying the conditions desired for the light emitting layer 35. 100 nm or less.

  2 shows only one embodiment of the electroluminescent element according to the present invention, and the electroluminescent element according to the present invention is not limited to the illustrated configuration. For example, the stacked structure is the reverse of that shown in FIG. 2, that is, the cathode 38, the electron injection layer 37, the electron transport layer 36, the light emitting layer 35, the hole transport layer 34, the hole injection layer 33 and the anode on the substrate 31. It is also possible to stack 32 in this order.

  The configuration of the electroluminescent device according to the present invention is not particularly limited, and the anode and the cathode are arranged in an XY matrix, whether it is a single device or an element having a structure arranged in an array. It may be an element having an arranged structure.

<6. Photoelectric conversion element>
The photoelectric conversion element according to the present invention includes a cathode and an anode that are a pair of electrodes, and an active layer that is a semiconductor layer disposed between the electrodes. In addition, the photoelectric conversion element according to an embodiment may include other components including a base material, an electron extraction layer, and a hole extraction layer. In one embodiment, the active layer contains the fullerene compound according to the present invention. However, in another embodiment, the photoelectric conversion element may have a layer containing the fullerene compound according to the present invention, which is different from the active layer. For example, the electron extraction layer or the like may contain the fullerene compound according to the present invention.

  FIG. 3 is a cross-sectional view schematically showing an embodiment of the photoelectric conversion element according to the present invention. The photoelectric conversion element shown in FIG. 3 is a photoelectric conversion element used in a general thin-film solar cell, but the photoelectric conversion element according to the present invention is not limited to that shown in FIG. A photoelectric conversion element 100 according to an embodiment of the present invention includes a base material 107, a cathode (electrode) 101, an electron extraction layer (buffer layer) 102, an active layer 103, a hole extraction layer (buffer layer) 104, and an anode (electrode). ) 106 has a layered structure formed in this order. Note that the electron extraction layer 102 and the hole extraction layer 104 are not necessarily provided. A work function tuning layer may be present between the cathode 101 and the electron extraction layer 102.

<6-1. Active layer (103)>
The active layer 103 is a layer where photoelectric conversion is performed. When the photoelectric conversion element 100 receives light, the light is absorbed by the active layer 103 to generate carriers, and the generated carriers are extracted from the cathode 101 and the anode 106.

  The structure of the active layer 103 is not particularly limited. For example, the active layer 103 may be a heterojunction active layer including a p-layer containing a p-type semiconductor compound and an n-layer containing an n-type semiconductor compound. When light enters such an active layer 103, carrier separation occurs at the layer interface, and the generated carriers (holes and electrons) are transported to the cathode 101 and the anode 106. In one embodiment, the n layer contains the fullerene compound according to the present invention as an n-type semiconductor material.

  In one embodiment, the active layer 103 is a bulk hetero active layer having a layer (i layer) in which a p-type semiconductor compound and an n-type semiconductor compound are mixed. In the i layer, the p-type semiconductor compound and the n-type semiconductor compound are phase-separated. When light enters the i layer, carrier separation occurs at the phase interface, and the generated carriers (holes and electrons) are transported to the cathode 101 and the anode 106. In the i layer, at least one of a p layer containing a p-type semiconductor compound and an n layer containing an n-type semiconductor compound may be laminated. In one embodiment, at least one of the i layer and the n layer contains the fullerene compound according to the present invention as an n-type semiconductor material.

  In other embodiments, the active layer 103 is a layer containing a perovskite semiconductor compound, and a solar cell having such an active layer 103 is known as a perovskite solar cell. In the perovskite semiconductor, a perovskite semiconductor compound having a perovskite structure forms a crystal. In such crystals, fast charge separation occurs and the diffusion distance of holes and electrons is long, so that efficient charge separation occurs.

  There is no particular limitation on the thickness of the active layer 103. In terms of the ability to absorb more light, the thickness of the active layer 103 is preferably 5 nm or more, more preferably 10 nm or more, more preferably 50 nm or more, and particularly preferably 120 nm or more. On the other hand, the thickness of the active layer 103 is preferably 500 nm or less, more preferably 400 nm or less, and more preferably 300 nm or less in that the series resistance decreases.

(Heterojunction type active layer and bulk hetero type active layer)
There is no particular limitation on the p-type semiconductor compound contained in the heterojunction type or bulk hetero type active layer 103. For example, those exemplified as the p-type semiconductor compound that may be contained in the semiconductor layer can be used. As the p-type polymer semiconductor compound, a polymer semiconductor compound that is a copolymer of two or more monomer units is preferably used. Examples of such optoelectronic semiconductor compounds include Accounts of Chemical Research, 2012, 45, 723-733, Macromolecules, 2012, 45, 607-632, Chemistry of Materials, 2011, 23, 456-469, Energy & Environmental Science. , 2011, 4, 1225-1237, Progress in Polymer Science, 2011, 36, 1326-1414, Journal of Materials Chemistry, 2012, 22, 10416-10434, and Progress in Polymer Science, 2012, 37, 1292-1331. What is done. Moreover, the derivative | guide_body of these high molecular semiconductor compounds can also be used, and the high molecular semiconductor compound obtained by copolymerization of the monomer described in said literature can also be used. Furthermore, in order to control solubility, crystallinity, film formability, HOMO energy level, LUMO energy level, and the like, substituents may be introduced into these polymer semiconductor compounds.

  Two or more p-type semiconductor compounds may be used as the p-type semiconductor compound. From the viewpoint of promoting charge separation, it is preferable to use a p-type semiconductor compound having an energy band gap of 1.0 eV to 1.8 eV. In addition, it is preferable to use a polymer semiconductor compound that can be dissolved in a solvent in that the active layer 103 can be formed using a simple coating process.

  There is no particular limitation on the n-type semiconductor compound contained in the heterojunction type or bulk hetero type active layer 103. For example, those exemplified as the n-type semiconductor compound that may be contained in the semiconductor layer can be used.

  Among these, it is preferable to use the fullerene compound according to the present invention as the n-type semiconductor compound. As other n-type semiconductor compounds, fullerene compounds, borane derivatives, thiazole derivatives, benzothiazole derivatives, benzothiadiazole derivatives, N-alkyl substituted naphthalene tetracarboxylic acid diimides or N-alkyl substituted perylene diimide derivatives are preferable, More preferred are fullerene compounds, N-alkyl substituted perylene diimide derivatives, N-alkyl substituted naphthalene tetracarboxylic acid diimides or n-type polymers. Two or more n-type semiconductor compounds may be used.

  In the bulk hetero type active layer 103, the mass ratio of the p-type semiconductor compound to the n-type semiconductor compound in the i layer (p-type semiconductor compound / n-type semiconductor compound) is not particularly limited, but a good phase separation structure is obtained. In view of improving the photoelectric conversion efficiency, it is preferably 0.15 or more, more preferably 0.3 or more, on the other hand, preferably 4 or less, and more preferably 2 or less. Is particularly preferably 0.8 or less.

(Active layer containing perovskite semiconductor compound)
The perovskite semiconductor compound is not particularly limited, and those described above can be used. Preferred structures of the perovskite compound include those represented by the general formula AMX ₃ and those represented by the general formula A ₂ MX ₄ .

  Although the monovalent cation A is not particularly limited, for example, those described in the above-mentioned book of Galasso can be used. More specific examples include cations including Group 1 and Group 13 to Group 16 elements of the periodic table. Among these, cesium ion, rubidium ion, ammonium ion which may have a substituent, or phosphonium ion which may have a substituent are preferable. As an example of the ammonium ion which may have a substituent, a primary ammonium ion or a secondary ammonium ion is mentioned. There is no particular limitation on the substituent. Specific examples of the ammonium ion that may have a substituent include alkylammonium ions and arylammonium ions. In particular, in order to avoid steric hindrance, it is preferable to use a monoalkylammonium ion having a three-dimensional crystal structure. Moreover, the combination of 2 or more types of cations can also be used as the cation A.

  Specific examples of the monovalent cation A include methylammonium ion, ethylammonium ion, isopropylammonium ion, n-propylammonium ion, isobutylammonium ion, n-butylammonium ion, t-butylammonium ion, dimethylammonium ion, and diethylammonium ion. Examples thereof include an ion, a phenylammonium ion, a benzylammonium ion, a phenethylammonium ion, a guanidinium ion, a formamidinium ion, an acetamidinium ion, and an imidazolium ion.

The divalent cation M is not particularly limited, but is preferably a divalent metal cation or a semimetal cation. Specific examples include cations of Group 14 elements of the periodic table, and more specific examples include lead cations (Pb ²⁺ ), tin cations (Sn ²⁺ ), and germanium cations (Ge ²⁺ ). Moreover, the combination of 2 or more types of cations can also be used as the cation M. From the viewpoint of obtaining a stable photoelectric conversion element, it is particularly preferable to use a lead cation or two or more cations including a lead cation.

  Examples of monovalent anions X include halide ion, acetate ion, nitrate ion, sulfate ion, borate ion, acetylacetonate ion, carbonate ion, citrate ion, sulfur ion, tellurium ion, thiocyanate ion, titanate. An ion, a zirconate ion, a 2,4-pentanedionate ion, or a silicofluorine ion. In order to adjust the band gap, X may be one type of anion or a combination of two or more types of anions. Among these, X is preferably a halide ion or a combination of a halide ion and other anions. Examples of the halide ion X include chloride ion, bromide ion or iodide ion. From the viewpoint of not excessively widening the band gap of the semiconductor, it is preferable to use iodide ions.

Preferable examples of the perovskite semiconductor compound include organic-inorganic perovskite semiconductor compounds, and particularly halide organic-inorganic perovskite semiconductor compounds. Specific examples of the perovskite semiconductor compound include CH ₃ NH ₃ PbI ₃ , CH ₃ NH ₃ PbBr ₃ , CH ₃ NH ₃ PbCl ₃ , CH ₃ NH ₃ SnI ₃ , CH ₃ NH ₃ SnBr ₃ , and CH ₃ NH ₃ Sn _3. CH ₃ NH ₃ PbI _(3-x) Cl _x , CH ₃ NH ₃ PbI _(3-x) Br _x , CH ₃ NH ₃ PbBr _(3-x) Cl _x , CH ₃ NH ₃ Pb _(1-y) Sn _y I ₃ , CH ₃ NH ₃ Pb _(1-y) Sn _y Br ₃ , CH ₃ NH ₃ Pb _(1-y) Sn _y Cl ₃ , CH ₃ NH ₃ Pb _(1-y) Sn _y I _{(3 -x) Cl x, CH 3 NH} 3 Pb (1-y) Sn y I (3-x) Br x, CH 3 NH 3 Pb (1-y) Sn y Br (3-x) Cl x, is equal Cited . Note that x is an arbitrary value from 0 to 3, and y is an arbitrary value from 0 to 1.

  From the viewpoint of improving the photoelectric conversion efficiency, it is preferable to use a semiconductor compound having an energy band gap of 1.0 eV to 3.5 eV as the perovskite semiconductor compound.

  The active layer 103 may contain two or more types of perovskite semiconductor compounds. For example, two or more types of perovskite semiconductor compounds in which at least one of A, M, and X is different may be included in the active layer 103.

  The amount of the perovskite semiconductor compound contained in the active layer 103 is preferably 50% by mass or more, more preferably 70% by mass or more, more preferably 80% by mass or more so that good photoelectric conversion characteristics can be obtained. It is. There is no restriction | limiting in an upper limit, and it is 100 mass% or less.

  The active layer 103 may contain an additive in addition to the perovskite semiconductor compound. The additive is not particularly limited, and examples of the additive include inorganic compounds such as halides, oxides, or inorganic salts such as sulfides, sulfates, nitrates, and ammonium salts. The amount of the additive in the active layer 103 is preferably 50% by mass or less, more preferably 30% by mass or less, and more preferably 20% by mass or less so that good photoelectric conversion characteristics can be obtained. . There is no restriction | limiting in a lower limit, and it is 0 mass% or more.

(Method for forming active layer)
The formation method of the active layer 103 is not particularly limited, and any method can be used. Specific examples include a coating method and a vapor deposition method (or a co-evaporation method). It is preferable to use a coating method because the active layer 103 can be easily formed. Hereinafter, a method for forming the active layer 103 by a coating method will be described.

  The bulk hetero type active layer 103 can be formed by preparing a coating liquid containing a p-type semiconductor compound, an n-type semiconductor compound, and a solvent, and applying the coating liquid. This coating solution may further contain an additive. Moreover, you may use the mixed solvent of a high boiling point solvent and a low boiling point solvent as a solvent. By using such an additive or mixed solvent, the volatilization rate of the solvent can be adjusted, and the organization of the semiconductor compound can be promoted to optimize the phase separation structure.

  Although any method can be used as a coating method of the coating solution, for example, spin coating method, ink jet method, doctor blade method, drop casting method, reverse roll coating method, gravure coating method, kiss coating method, roll brush method, Examples thereof include a spray coating method, an air knife coating method, a wire barber coating method, a pipe doctor method, an impregnation / coating method, and a curtain coating method.

  You may heat-dry after apply | coating a coating liquid. By heating the bulk hetero active layer 103, self-organization of the active layer can be promoted. The heating temperature is preferably 50 ° C. or higher, more preferably 80 ° C. or higher, so that the effect of self-organization can be obtained. On the other hand, preferably no higher than 300 ° C., more preferably so as not to cause damage due to heat. It is 280 degrees C or less, More preferably, it is 250 degrees C or less. The heating time is preferably 1 minute or more, more preferably 3 minutes or more, so that the effect of self-organization can be obtained. On the other hand, from the viewpoint of improving the processing efficiency, preferably 3 hours or less, more preferably Is less than 1 hour.

  The solvent for the coating solution is not particularly limited as long as it can uniformly dissolve the p-type semiconductor compound and the n-type semiconductor compound. For example, what was mentioned as a solvent which can be used when forming a semiconductor layer by the apply | coating method can be used. Among them, aromatic hydrocarbons such as toluene, xylene, mesitylene, cyclohexylbenzene, chlorobenzene or orthodichlorobenzene; cycloaliphatic carbonization such as cyclopentane, cyclohexane, methylcyclohexane, cycloheptane, cyclooctane, tetralin or decalin Hydrogen; ketones such as acetone, methyl ethyl ketone, cyclopentanone or cyclohexanone; or ethers such as ethyl ether, tetrahydrofuran or dioxane. On the other hand, it is preferable to use a non-halogen solvent from the viewpoint of environmental burden.

  More preferably, non-halogen aromatic hydrocarbons such as toluene, xylene, mesitylene or cyclohexylbenzene; non-halogen ketones such as acetone, methyl ethyl ketone, cyclopentanone or cyclohexanone; aromatic ketones such as acetophenone or propiophenone Non-halogen alicyclic hydrocarbons such as tetrahydrofuran, cyclopentane, cyclohexane, methylcyclohexane, cycloheptane, cyclooctane, tetralin or decalin; or non-halogen aliphatic ethers such as 1,4-dioxane; . Particularly preferred are non-halogen aromatic hydrocarbons such as toluene, xylene, mesitylene or cyclohexylbenzene. As the solvent, one kind of solvent may be used alone, or any two or more kinds of solvents may be used in any ratio.

  As the high boiling point solvent, it is preferable to use a solvent having a boiling point of 180 ° C. or higher and 250 ° C. or lower under normal pressure, and specific examples include tetralin, decalin, acetophenone, and the like. As the low boiling point solvent, a solvent having a boiling point of 60 ° C. or higher and 150 ° C. or lower under normal pressure is preferably used, and specific examples include toluene, xylene, tetrahydrofuran, ethyl methyl ketone, and the like. By combining solvents having such boiling points, the organization of the semiconductor compound can be promoted. From the viewpoint of environmental burden, these high-boiling solvents and low-boiling solvents are preferably non-halogen solvents.

  The ratio between the high boiling point solvent and the low boiling point solvent is not particularly limited. In terms of facilitating the organization of the semiconductor compound, the weight ratio (high boiling point solvent / low boiling point solvent) is preferably 1/20 or more, more preferably 1/15 or more, and 1/10 or more. More preferably. On the other hand, the weight ratio (high boiling point solvent / low boiling point solvent) is preferably 10/1 or less, more preferably 2/1 or less, more preferably 1/1 or less, and more preferably 1/2 or less. It is particularly preferred that

  Examples of combinations of low and high boiling solvents include non-halogen aromatic hydrocarbons and alicyclic hydrocarbons, non-halogen aromatic hydrocarbons and aromatic ketones, ethers and alicyclic carbonization. Examples thereof include hydrogens, ethers and aromatic ketones, aliphatic ketones and alicyclic hydrocarbons, or aliphatic ketones and aromatic ketones. Specific examples of preferred combinations include toluene and tetralin, xylene and tetralin, toluene and acetophenone, xylene and acetophenone, tetrahydrofuran and tetralin, tetrahydrofuran and acetophenone, methyl ethyl ketone and tetralin, methyl ethyl ketone and acetophenone, and the like.

  When the coating solution contains an additive, the amount of the additive with respect to the entire coating solution is preferably 0.01% by mass or more, more preferably 0.1% by mass or more in terms of facilitating the organization of the semiconductor compound. More preferably, it is preferably 10% by mass or less, more preferably 5% by mass or less.

  The coating solution can be prepared by preparing a solution of a p-type semiconductor compound and a solution of an n-type semiconductor compound, and then mixing these solutions. The coating liquid can also be produced by dissolving a p-type semiconductor compound and an n-type semiconductor compound in a solvent.

  The total concentration of the p-type semiconductor compound and the n-type semiconductor compound in the coating solution is not particularly limited. From the viewpoint of forming an active layer having a sufficient thickness, the total concentration is preferably 0.3% by mass or more based on the entire coating solution. Further, from the viewpoint of sufficiently dissolving the semiconductor compound, the total concentration is preferably 20% by mass or less with respect to the entire coating solution.

  Furthermore, when forming a bulk hetero type | mold active layer (i layer) using a semiconductor compound precursor, the following methods can also be used. First, after applying a coating solution containing a semiconductor compound precursor and a readily soluble compound to form a layer, the semiconductor compound precursor is converted into a first semiconductor compound (for example, a p-type semiconductor compound). Next, the easily soluble compound is replaced with the second semiconductor compound by applying a coating liquid containing a second semiconductor compound (for example, an n-type semiconductor compound) to the obtained layer. By such a method, a bulk hetero active layer in which the first semiconductor compound and the second semiconductor compound are preferably phase-separated can be obtained. The easily soluble compound is not particularly limited, and for example, those described in JP2013-254949A can be used. Specific examples of the readily soluble compound include 4 ', 4 "-tri-9-carbazolyltriphenylamine (TCTA).

  The heterojunction active layer 103 is formed by preparing a coating solution containing a p-type semiconductor compound and a solvent and a coating solution containing an n-type semiconductor compound and a solvent, and sequentially applying these coating solutions. can do. There is no particular limitation on the solvent and the coating method, and the solvent and the coating method described in the method for forming the bulk hetero type active layer can be used. As in the case of producing a bulk hetero type active layer, it is preferable to heat-dry after applying each coating solution. In addition, as in the case of producing a bulk hetero type active layer, each coating solution may contain an additive.

  Even when the active layer 103 containing the perovskite semiconductor compound is formed, there is no particular limitation on the method of forming the active layer 103. As an example, a method of preparing a coating solution containing a compound represented by the following formula (2), a compound represented by the following formula (3) and a solvent, and coating the coating solution can be mentioned. Such a coating solution can be prepared by heating and stirring the compound in the solution. According to this method, the active layer 103 containing a compound represented by the following formula (1) can be produced.

  As another example, after applying a coating liquid containing a compound represented by the following formula (3) and a solvent, a coating liquid containing a compound represented by the following formula (2) and a solvent was applied. And a method of heat annealing. Also by this method, the active layer 103 containing the compound represented by the following formula (1) can be produced.

AMX ₃ (1)
AX (2)
MX ₂ (3)
The definitions of A, M and X are as described above. Specific examples of the AX include alkylammonium salts halides, and metal halides Examples of MX _2. AX and MX ₂ are precursors of the velovskite semiconductor compound AMX ₃ .

  The heating temperature at the time of heating and stirring or heating annealing is preferably 60 ° C. or higher from the viewpoint of sufficiently promoting the reaction of the compound, and is preferably 150 ° C. or lower from the viewpoint of avoiding side reactions. The heating and stirring time is preferably 2 hours or longer from the viewpoint of sufficiently promoting the reaction of the compound, and preferably 24 hours or shorter from the viewpoint of improving production efficiency. The annealing method is not particularly limited, and may be performed using a hot plate or a near infrared heating device (NIR).

The molar fraction (2/3) of the compound represented by the formula (2) with respect to the compound represented by the formula (3) is not particularly limited. However, when MX ₂ remains in the active layer, the conversion efficiency of the photoelectric conversion element tends to decrease. Moreover, even if the compound represented by Formula (2) can be removed by the heat treatment described later, the compound represented by Formula (3) is often difficult to remove by heating. Therefore, it is preferable to form the active layer 103 so that the compound represented by the formula (3) does not remain in the layer. From this point, the molar fraction (2/3) of the compound represented by the formula (2) with respect to the compound represented by the formula (3) is preferably 100 mol% or more, while it is 600 mol% or less. It is preferable that it is 400 mol% or less.

  The total amount of the compound represented by the formula (2) and / or the compound represented by the formula (3) with respect to the total amount of the coating solution is preferably 10 masses in order to produce the active layer 103 having a sufficient thickness. % Or more, more preferably 15% by mass or more, and particularly preferably 20% by mass or more. On the other hand, in order to avoid precipitation in a solvent, it is preferably 50% by mass or less, more preferably 45% by mass or less, and particularly preferably 40% by mass or less.

  Moreover, in order to accelerate | stimulate crystal formation, the coating liquid may contain the additive further. In this case, the amount of the additive is preferably 50 with respect to the total amount of the compound represented by the formula (2) and / or the compound represented by (3) so that good photoelectric conversion performance can be obtained. It is not more than mass%, more preferably not more than 30 mass%, particularly preferably not more than 10 mass%.

  Also when forming the active layer 103 containing a perovskite semiconductor compound, it is preferable to heat-dry after apply | coating a coating liquid. The solvent coordinated by heating and the remaining compound represented by the formula (2) are removed from the layer, crystallization is promoted, and the photoelectric conversion efficiency tends to be improved. Since the progress of crystallization depends on the concentration of the coating solution, it is preferable to shorten the heating time when the concentration of the coating solution is low or the content of the solvent is small.

  The heating temperature at this time is not particularly limited, but is preferably 70 ° C. or higher, more preferably 90 ° C. or higher, from the viewpoint of sufficiently promoting crystallization. On the other hand, decomposition and side reactions of the perovskite semiconductor compound are performed. In order to suppress, it is preferably 150 ° C. or lower, more preferably 130 ° C. or lower, more preferably 120 ° C. or lower. The heating time is not particularly limited, but is preferably 10 minutes or longer, more preferably 30 minutes or longer, more preferably 1 hour or longer from the viewpoint of sufficiently promoting crystallization, while improving the production efficiency. From the viewpoint of making it, it is preferably 3 hours or less, more preferably 2 hours or less.

<6-2. Buffer layer (102, 104)>
The buffer layer can be generally classified into an electron extraction layer and a hole extraction layer. In one embodiment, the photoelectric conversion element 100 includes an electron extraction layer 102 between the cathode 101 and the active layer 103, and a hole extraction layer 104 between the active layer 103 and the anode 106. However, the photoelectric conversion element 100 may have only one of the electron extraction layer 102 and the hole extraction layer 104, or may not include either the electron extraction layer 102 or the hole extraction layer 104. Good.

  The electron extraction layer 102 and the hole extraction layer 104 are preferably disposed so as to sandwich the active layer 103 between a pair of electrodes (101, 106). That is, when the photoelectric conversion element 100 includes both the electron extraction layer 102 and the hole extraction layer 104, the anode (electrode) 106, the hole extraction layer 104, the active layer 103, the electron extraction layer 102, and the cathode (electrode) 101. Can be arranged in this order. When the photoelectric conversion element 100 includes the electron extraction layer 102 and does not include the hole extraction layer 104, the anode (electrode) 106, the active layer 103, the electron extraction layer 102, and the cathode (electrode) 101 may be arranged in this order. it can. The stacking order of the electron extraction layer 102 and the hole extraction layer 104 may be reversed. Further, at least one of the electron extraction layer 102 and the hole extraction layer 104 may be composed of a plurality of different films.

(Electronic extraction layer)
There is no particular limitation on the material of the electron extraction layer 102, and any material can be used as long as it can improve the efficiency of extracting electrons from the active layer 103 to the cathode 101. As a material for the electron extraction layer 102, the fullerene compound according to the present invention can be used. In one embodiment, the electron extraction layer 102 contains the fullerene compound according to the present invention as a main component, but may further include other electron extraction layer materials or additives.

  Examples of other materials for the electron extraction layer 102 include inorganic compounds, organic compounds, or publicly known documents such as International Publication No. 2013/171517, International Publication No. 2013/180230, or Japanese Patent Application Laid-Open No. 2012-191194, or The organic-inorganic perovskite compound according to the present invention is exemplified. For example, examples of the inorganic compound include salts of alkali metals such as lithium, sodium, potassium, and cesium, and metal oxides such as zinc oxide, titanium oxide, aluminum oxide, and indium oxide. Examples of the organic compound include bathocuproine (BCP), bathophenanthrene (Bphen), (8-hydroxyquinolinato) aluminum (Alq3), boron compound, oxadiazole compound, benzimidazole compound, naphthalenetetracarboxylic anhydride (NTCDA), Examples include perylene tetracarboxylic acid anhydride (PTCDA), fullerene compounds, or phosphine compounds having a double bond with a Group 16 element of the periodic table such as phosphine oxide compounds or phosphine sulfide compounds.

  There is no particular limitation on the method for forming the electron extraction layer 102. When a compound having sublimation properties is used as a material, it can be formed by a dry film formation method such as a vacuum evaporation method. Further, when a compound soluble in a solvent is used as a material, it can be formed by a wet film forming method such as a spin coating method or an ink jet method. Note that as the solvent, the solvents described in the description of the method for forming the active layer 103 can be used. In the case of using the wet film forming method, any method can be used as a coating method of the coating liquid containing the material of the electron extraction layer 102. Examples thereof include spin coating, gravure coating, kiss coating, roll brushing, spray coating, air knife coating, wire barber coating, pipe doctor method, impregnation / coating method, and curtain coating method. Moreover, only 1 type of method may be used as a coating method, and it can also be used in combination of 2 or more types.

  The total film thickness of the electron extraction layer 102 is not particularly limited, but is preferably 0.5 nm or more, more preferably 1 nm or more, more preferably 5 nm or more, and particularly preferably 10 nm or more. On the other hand, it is preferably 1 μm or less, more preferably 700 nm or less, more preferably 400 nm or less, and particularly preferably 200 nm or less. When the film thickness of the electron extraction layer 102 is within the above range, uniform application is facilitated, and the electron extraction function can be exhibited well.

(Hole extraction layer)
The material of the hole extraction layer 104 is not particularly limited as long as it is a material capable of improving the efficiency of extracting holes from the active layer 103 to the anode 106. Specifically, inorganic compounds, organic compounds, or organic / inorganic perovskite compounds according to the present invention described in publicly known documents such as International Publication Nos. 2013/171517, 2013/180230, and 2012-191194. Is mentioned. For example, examples of the inorganic compound include metal oxides such as copper oxide, nickel oxide, manganese oxide, iron oxide, molybdenum oxide, vanadium oxide, and tungsten oxide. In addition, as an organic compound, a conductive polymer in which polythiophene, polypyrrole, polyacetylene, triphenylenediamine, polyaniline, or the like is doped with sulfonic acid, iodine, or the like (for example, PEDOT: PSS or doped P3HT), a sulfonyl group as a substituent And polythiophene derivatives, conductive organic compounds such as arylamine, Nafion, or lithium-doped spiro-OMeTAD.

  The total film thickness of the hole extraction layer 104 is not particularly limited, but is preferably 0.5 nm or more. On the other hand, it is preferably 400 nm or less, more preferably 200 nm or less. When the thickness of the hole extraction layer 104 is 0.5 nm or more, the function as a buffer material is performed well, and when the thickness of the hole extraction layer 104 is 400 nm or less, holes are easily extracted. Thus, the photoelectric conversion efficiency can be improved.

  There is no limitation on the formation method of the hole extraction layer 104. When a compound having sublimation property is used, it can be formed by a dry film forming method such as a vacuum vapor deposition method. Further, when a compound soluble in a solvent is used, it can be formed by a wet film forming method such as a spin coating method or an ink jet method. Note that as the solvent, the solvents described in the description of the method for forming the active layer 103 can be used.

<6-3. Electrode (101, 106)>
The electrode has a function of collecting holes and electrons generated by light absorption. Therefore, it is preferable to use the anode 106 suitable for collecting holes and the cathode 101 suitable for collecting electrons as the pair of electrodes. Any one of the pair of electrodes may be translucent, and both may be translucent. Translucency means that sunlight passes through 40% or more. Moreover, it is preferable that the transparent electrode has a solar ray transmittance of 70% or more because more light passes through the transparent electrode and reaches the active layer 103. The light transmittance can be measured with a spectrophotometer (for example, U-4100 manufactured by Hitachi High-Tech).

  There are no particular limitations on the constituent members of the cathode 101 and the anode 106 and the manufacturing method thereof, and well-known techniques can be used. For example, members described in publicly known documents such as International Publication No. 2013/171517, International Publication No. 2013/180230, or Japanese Patent Application Laid-Open No. 2012-191194 and a manufacturing method thereof can be used.

<6-4. Substrate (107)>
The photoelectric conversion element 100 has the base material 107 used as a support body normally. But the photoelectric conversion element which concerns on this invention does not need to have the base material 107. FIG. The material of the base material 107 is not particularly limited as long as the effects of the present invention are not significantly impaired. For example, publicly known documents such as International Publication No. 2013/171517, International Publication No. 2013/180230, or Japanese Unexamined Patent Application Publication No. 2012-191194. The materials described in can be used.

<6-5. Method for manufacturing photoelectric conversion element>
The photoelectric conversion element 100 can be manufactured by forming each layer constituting the photoelectric conversion element 100 in accordance with the above-described method. There is no particular limitation on the method of forming each layer constituting the photoelectric conversion element 100, and the layers can be formed by a sheet-to-sheet (manyoba) method or a roll-to-roll method.

  The roll-to-roll method is a method in which a flexible base material wound in a roll shape is fed out and processed intermittently or continuously while being wound up by a take-up roll. is there. According to the roll-to-roll method, it is possible to batch-process long substrates of the order of km, and the roll-to-roll method is more suitable for mass production than the sheet-to-sheet method. On the other hand, when attempting to form each layer by the roll-to-roll method, the film may be damaged or partially peeled due to the contact between the film-forming surface and the roll due to its structure.

  The size of the roll that can be used in the roll-to-roll method is not particularly limited as long as it can be handled by a roll-to-roll manufacturing apparatus, but the upper limit of the outer diameter is preferably 5 m or less, more preferably 3 m or less, and more preferably 1 m or less. On the other hand, the lower limit is preferably 10 cm or more, more preferably 20 cm or more, more preferably 30 cm or more. The upper limit of the outer diameter of the roll core is preferably 4 m or less, more preferably 3 m or less, and more preferably 0.5 m or less. On the other hand, the lower limit is preferably 1 cm or more, more preferably 3 cm or more, more preferably 5 cm or more, still more preferably 10 cm or more, and particularly preferably 20 cm or more. It is preferable that these diameters are not more than the above upper limit from the viewpoint of high handleability of the roll, and it is preferable that the diameter is not less than the lower limit from the viewpoint that the layer formed in each step is less likely to be broken by bending stress. . The lower limit of the width of the roll is preferably 5 cm or more, more preferably 10 cm or more, more preferably 20 cm or more. On the other hand, the upper limit is preferably 5 m or less, more preferably 3 m or less, more preferably 2 m or less. It is preferable that the width is not more than the upper limit from the viewpoint of high handleability of the roll, and it is preferable that the width is not less than the lower limit because the degree of freedom of the size of the photoelectric conversion element 100 is increased.

  Further, after the cathode 101 or the anode 106 is laminated, the photoelectric conversion element 100 is preferably 50 ° C. or higher, more preferably 80 ° C. or higher, on the other hand, preferably 300 ° C. or lower, more preferably 280 ° C. or lower, more preferably 250 ° C. Heating is preferably performed in the following temperature range (this step may be referred to as an annealing treatment step). By performing the annealing process at a temperature of 50 ° C. or higher, the adhesion between the layers of the photoelectric conversion element 100, for example, the adhesion between the layers such as the electron extraction layer 102 and the cathode 101 and the electron extraction layer 102 and the active layer 103 is improved. This is preferable because the effect of By improving the adhesion between the layers, the thermal stability and durability of the photoelectric conversion element can be improved. It is preferable to set the temperature of the annealing treatment step to 300 ° C. or lower because the organic compound contained in the photoelectric conversion element 100 is less likely to be thermally decomposed. In the annealing process, stepwise heating using different temperatures within the above temperature range may be performed.

  The heating time is preferably 1 minute or more, more preferably 3 minutes or more, on the other hand, preferably 180 minutes or less, more preferably 60 minutes or less in order to improve adhesion while suppressing thermal decomposition. The annealing treatment step is preferably terminated when the open-circuit voltage, the short-circuit current, and the fill factor, which are parameters of the solar cell performance, reach a constant value. Further, the annealing treatment step is preferably performed under normal pressure and in an inert gas atmosphere in order to prevent thermal oxidation of the constituent materials. As a heating method, the photoelectric conversion element may be placed on a heat source such as a hot plate, or the photoelectric conversion element may be placed in a heating atmosphere such as an oven. The heating may be performed batchwise or continuously.

<6-6. Photoelectric conversion characteristics>
The photoelectric conversion characteristics of the photoelectric conversion element 100 can be obtained as follows. The photoelectric conversion element 100 is irradiated with light having an AM1.5G condition at an irradiation intensity of 100 mW / cm ^{2 using a} solar simulator, and current-voltage characteristics are measured. From the obtained current-voltage curve, photoelectric conversion characteristics such as photoelectric conversion efficiency (PCE), short circuit current density (Jsc), open circuit voltage (Voc), fill factor (FF), series resistance, and shunt resistance can be obtained.

  The photoelectric conversion efficiency of the photoelectric conversion element 100 is not particularly limited, but is preferably 1% or more, more preferably 1.5% or more, and more preferably 2% or more. On the other hand, there is no particular limitation on the upper limit, and the higher the better. Further, the fill factor of the photoelectric conversion element 100 is not particularly limited, but is preferably 0.6 or more, more preferably 0.7 or more, and more preferably 0.9 or more. On the other hand, there is no particular limitation on the upper limit, and the higher the better.

<7. Solar cell>
The photoelectric conversion element 100 according to the present invention is preferably used as a solar cell, particularly a solar cell element of a thin film solar cell. FIG. 4 is a cross-sectional view schematically showing a configuration of a solar cell according to an embodiment of the present invention. FIG. 4 shows a thin-film solar cell that is a solar cell according to an embodiment of the present invention. As shown in FIG. 4, the thin-film solar cell 14 according to this embodiment includes a weather-resistant protective film 1, an ultraviolet cut film 2, a gas barrier film 3, a getter material film 4, a sealing material 5, and a solar cell. The element 6, the sealing material 7, the getter material film 8, the gas barrier film 9, and the back sheet 10 are provided in this order. The thin film solar cell 14 according to the present embodiment has the photoelectric conversion element according to the present invention as the solar cell element 6. And light is irradiated from the side (downward in Drawing 4) in which weatherproof protective film 1 was formed, and solar cell element 6 generates electricity. In addition, the thin film solar cell 14 does not need to have all these structural members, and can select a required structural member arbitrarily.

  There are no particular restrictions on these constituent members constituting the thin-film solar cell and the manufacturing method thereof, and well-known techniques can be used. For example, techniques described in publicly known documents such as International Publication No. 2013/171517, International Publication No. 2013/180230, or Japanese Patent Application Laid-Open No. 2012-191194 can be used.

  There is no restriction | limiting in the use of the solar cell which concerns on this invention, especially the thin film solar cell 14 mentioned above, It can use for arbitrary uses. For example, a solar cell according to one embodiment includes a solar cell for building materials, a solar cell for automobiles, a solar cell for interiors, a solar cell for railways, a solar cell for ships, a solar cell for airplanes, a solar cell for spacecraft, and a solar cell for home appliances. It can be used as a battery, a solar cell for mobile phones or a solar cell for toys.

  The solar cell according to the present invention, particularly the thin film solar cell 14 described above, may be used as it is, or may be used as a component of the solar cell module. For example, as shown in FIG. 5, a solar cell according to the present invention, in particular, a solar cell module 13 provided with the above-described thin film solar cell 14 on a substrate 12 is manufactured, and the solar cell module 13 is installed at a place of use. Can be used. A well-known technique can be used as the base material 12, for example, as the material of the base material 12, a material described in International Publication No. 2013/171517, International Publication No. 2013/180230, or Japanese Patent Application Laid-Open No. 2012-191194. Can be used. For example, when a building material plate is used as the substrate 12, a solar cell panel for an outer wall of a building can be produced as the solar cell module 13 by providing the thin film solar cell 14 on the surface of the plate.

  Hereinafter, embodiments of the present invention will be described by way of examples. However, the present invention is not limited to the following examples unless it exceeds the gist.

[Synthesis Example 1-1]
<Synthesis of Fullerene Compounds (S1) and (P1)>

  1,4-bis (trimethylsilylmethyl) [60] fullerene (S1), which is a fullerene compound, was synthesized with reference to the description in JP-A-2009-206470.

  1,4-bis (trimethylsilylmethyl) [60] fullerene (S1) (210 mg, 0.235 mmol) was placed in a heat-resistant glass tube, and heated at 350 ° C. for 30 minutes under reduced pressure in an electric furnace. After allowing to cool, the product is purified by gel filtration chromatography (toluene) and dried under reduced pressure to obtain the target fullerene compound 2 ′, 2′-dimethyl-2′-silapropano [60] fullerene (P1) in black. Obtained as a brown solid.

[Synthesis Example 1-2]
<Synthesis of Fullerene Compounds (S2) and (P2)>

  1,4-bis (dimethylphenylsilylmethyl) [60] fullerene (S2), which is a fullerene compound, was synthesized with reference to the description in JP-A-2009-206470.

  1,4-bis (dimethylphenylsilylmethyl) [60] fullerene (S2) (144 mg, 0.141 mmol) was placed in a heat-resistant glass tube, and heated at 350 ° C. for 30 minutes under reduced pressure in an electric furnace. After cooling, it is purified by gel filtration chromatography (toluene) and dried under reduced pressure to obtain the target fullerene compound 2′-methyl-2′-phenyl-2′-silapropano [60] fullerene (P2). Obtained as a black-brown solid.

[Synthesis Example 2]
<Synthesis of Porphyrin Compound (CP)>
Tetrakis (bicyclo [2.2.2] octadiene) porphyrin (CP) was synthesized with reference to the description in JP-A-2003-304014.

[Synthesis Example 3]
<Synthesis of phosphine oxide compound (POPy ₂ )>
Phenyl dipyrenyl phosphine oxide (POPy ₂ ), which is a phosphine oxide compound, was synthesized with reference to the description in WO 2011/016430.

[Example 1-1]
A photoelectric conversion element having the structure shown in FIG. 4 was produced by the following method. A glass substrate on which an indium tin oxide (ITO) transparent conductive film (145 nm) used as a lower electrode is deposited is subjected to ultrasonic cleaning with a surfactant, water with ultrapure water, and ultrasonic cleaning with ultrapure water. After cleaning, the substrate was dried with nitrogen blow and subjected to ultraviolet ozone cleaning.

  Next, an aqueous dispersion of poly (3,4-ethylenedioxythiophene) poly (styrenesulfonic acid) filtered through a 0.45 μm polyvinylidene fluoride (PVDF) filter on the lower electrode (manufactured by HC Starck) The product name “CLEVIOUS (TM) PVP AI4083”) was spin-coated and then heat-dried at 120 ° C. for 10 minutes in an air atmosphere. Thereafter, heat treatment was performed at 180 ° C. for 3 minutes in a nitrogen atmosphere. Thus, a hole extraction layer was formed.

  Next, a hole was extracted from a solution in which the bicycloporphyrin compound (CP) obtained in Synthesis Example 2 was dissolved in a mixed solvent of chlorobenzene and chloroform (mass ratio of 2: 1) to 0.5 mass%. The layer was spin-coated (rotation speed 1500 rpm). After the application, heat treatment was performed on a hot plate at 180 ° C. for 20 minutes. By this heat treatment, the brown bicycloporphyrin compound (CP) film was thermally converted into a green tetrabenzoporphyrin (BP) film. Thus, a crystalline p layer having an average film thickness of 25 nm was obtained.

  Subsequently, the bicycloporphyrin compound (CP) obtained in Synthesis Example 2 and the compound (TCTA) (4,4 ′, 4 ″ -tri-9-carbazolyltriphenylamine, manufactured by Lumtec) were each reduced to 0. A solution dissolved in a mixed solvent of chlorobenzene and chloroform (mass ratio of 1: 1) was spin-coated on the p-layer (rotation speed: 1500 rpm) so that the amount was 0.6 mass% and 1.4 mass%. After coating, heat treatment was performed at 190 ° C. for 20 minutes to thermally convert the bicycloporphyrin compound (CP) to tetrabenzoporphyrin (BP).

  After the heat treatment, a toluene solution (0.6% by mass) of the fullerene compound (P1) obtained in Synthesis Example 1-1 was spun onto a film containing tetrabenzoporphyrin (BP) and the compound (TCTA). Coated (0.3 mL, rotation speed 1500 rpm). Thus, by replacing the compound (TCTA) with the fullerene compound (P1), the film containing the tetrabenzoporphyrin (BP) and the compound (TCTA) is converted into the tetrabenzoporphyrin (BP) and the fullerene compound (P1). It was converted into an i layer. An n layer containing a fullerene compound (P1) was formed on the i layer.

Next, a phosphine oxide compound (POPy ₂ ) layer having a thickness of 7 nm was formed as an electron extraction layer on the active layer including the p layer, the i layer, and the n layer by a resistance heating vacuum deposition method.

  Further, an aluminum layer having a thickness of 100 nm used as the upper electrode was formed on the electron extraction layer by a resistance heating vacuum deposition method. In this way, a photoelectric conversion element was produced.

  After the device thus obtained was taken out into the glove box, the device was sealed by bonding the back glass plate disposed on the upper electrode side and the glass substrate with a photo-curing resin. As described above, a photoelectric conversion element having a light receiving area portion having a size of 4 mm × 4 mm was obtained.

[Example 1-2]
Photoelectric conversion as in Example 1-1, except that the fullerene compound (P2) obtained in Synthesis Example 1-2 was used in place of the fullerene compound (P1) when forming the i layer and the n layer. An element was produced.

[Example 1-3]
A phenanthroline compound (NBPhen, 2,9-bis (2-naphthyl) -4,7-diphenyl-1,10-phenanthroline, manufactured by Lumtec) is used in place of the phosphine oxide compound (POPy ₂ ) as a material for the electron extraction layer. A photoelectric conversion element was produced in the same manner as in Example 1-2.

[Comparative Example 1-1]
Photoelectric conversion as in Example 1-1, except that the fullerene compound (S1) obtained in Synthesis Example 1-1 was used in place of the fullerene compound (P1) when forming the i layer and the n layer. An element was produced.

[Comparative Example 1-2]
Photoelectric conversion as in Example 1-2, except that the fullerene compound (S2) obtained in Synthesis Example 1-2 was used instead of the fullerene compound (P2) when forming the i layer and the n layer. An element was produced.

[Comparative Example 1-3]
when forming the i-layer and n-layer, following the fullerene compound in place of the fullerene compound (P2) except using _{(C 60} Indenmono adduct, ICMA) (S3), in the same manner as in Example 1-2 A photoelectric conversion element was produced.

For each of the photoelectric conversion elements obtained in Examples 1-1 to 1-3 and Comparative Examples 1-1 to 1-3, a 4 mm square metal mask was attached, an air mass (AM) of 1.5, and an irradiance of 100 mW / Using a cm ² solar simulator, current-voltage characteristics were measured with a source meter (Keisley, Model 2400). The measurement results are shown in Table 1.

  As shown in Table 1, in the examples using the fullerene compound according to the present invention as the active layer material, a higher photoelectric conversion efficiency was obtained than in the comparative example.

[Example 2-1]
Lead (II) iodide and methylammonium iodide were dissolved in a mixed solvent of dimethyl sulfoxide and γ-butyrolactone (volume ratio 7: 3) so that the concentration in the solution was 4.8 mol / L, respectively. . The obtained solution was stirred and mixed by a stirrer at 60 ° C. for 12 hours under a nitrogen atmosphere. Thereafter, the solution was filtered with a 0.45 μm polytetrafluoroethylene (PTFE) filter to prepare a perovskite semiconductor coating solution.

  After cleaning a glass substrate on which an indium tin oxide (ITO) transparent conductive film used as a lower electrode is deposited in the order of ultrasonic cleaning with a surfactant, water with ultrapure water, and ultrasonic cleaning with ultrapure water. Then, it was dried with nitrogen blow and subjected to ultraviolet ozone cleaning.

  Next, an aqueous dispersion of poly (3,4-ethylenedioxythiophene) poly (styrenesulfonic acid) filtered through a 0.45 μm polyvinylidene fluoride (PVDF) filter on the lower electrode (manufactured by HC Starck) The product name “CLEVIOUSTM PVP AI4083”) was spin-coated and then heat-dried at 105 ° C. for 30 minutes in an air atmosphere. Thereafter, heat treatment was performed at 105 ° C. for 15 minutes in a nitrogen atmosphere. Thus, a hole extraction layer was formed.

  Next, the perovskite semiconductor coating solution prepared as described above is applied onto the hole extraction layer by spin coating in a nitrogen atmosphere, and a heat treatment is performed at 105 ° C. for 20 minutes in a nitrogen atmosphere, whereby an active layer is formed. As a result, a perovskite semiconductor layer was formed.

Thereafter, a chlorobenzene solution (20 mg / mL) in which the fullerene compound (P1) obtained in Synthesis Example 1-1 was dissolved was applied onto the active layer by spin coating. Furthermore, the _{C 60} layer having a thickness of 20 nm, the film thickness was successively formed by the 8nm of bathocuproine (BCP) layer, a resistance heating type vacuum deposition. Thus, an electron extraction layer having a three-layer structure was formed.

  Furthermore, an aluminum layer having a thickness of 120 nm used as the upper electrode was formed on the electron extraction layer by a resistance heating vacuum deposition method, and a 2 mm square photoelectric conversion element was produced.

[Example 2-2]
A photoelectric conversion device was produced in the same manner as in Example 2-1, except that the fullerene compound (P2) produced in Synthesis Example 1-2 was used instead of the fullerene compound (P1).

[Example 2-3]
A photoelectric conversion element was produced by the same method as in Example 2-2, except that the fullerene compound (P2) solution used in forming the electron extraction layer was prepared using toluene instead of chlorobenzene.

[Comparative Example 2-1]
A photoelectric conversion device was produced in the same manner as in Example 2-1, except that the fullerene compound (S1) was used instead of the fullerene compound (P1).

[Comparative Example 2-2]
A photoelectric conversion device was produced in the same manner as in Example 2-2 except that the fullerene compound (S2) was used instead of the fullerene compound (P2).

[Comparative Example 2-3]
A photoelectric conversion device was produced in the same manner as in Example 2-3 except that the fullerene compound (S2) was used instead of the fullerene compound (P2).

For each of the photoelectric conversion elements obtained in Examples 2-1 to 2-3 and Comparative Examples 2-1 to 2-3, a 1 mm square metal mask was attached, an air mass (AM) of 1.5, and an irradiance of 100 mW / Using a cm ² solar simulator, current-voltage characteristics were measured with a source meter (Keisley, Model 2400). The measurement results are shown in Table 2.

  As shown in Table 2, in the example using the fullerene compound according to the present invention as the electron extraction layer material, higher photoelectric conversion efficiency was obtained than in the comparative example.

DESCRIPTION OF SYMBOLS 1 Weatherproof protective film 2 Ultraviolet cut film 3,9 Gas barrier film 4,8 Getter material film 5,7 Sealing material 6 Solar cell element 10 Back sheet 12 Base material 13 Solar cell module 14 Thin film solar cell 31 Base material 32 Anode 33 Hole injection layer 34 Hole transport layer 35 Light emitting layer 36 Electron transport layer 37 Electron injection layer 38 Cathode 39 Electroluminescent device 51 Semiconductor layer 52 Insulator layers 53 and 54 Source electrode and drain electrode 55 Gate electrode 56 Base material 100 Photoelectric conversion Element 101 Cathode 102 Electron extraction layer 103 Active layer 104 Hole extraction layer 106 Anode 107 Base material

Claims (9)

A fullerene compound having a structure represented by the following formula (I).

(In the formula (I), ^{C f} represents a carbon atom constituting the fullerene ^ring, R 1 to R ⁶ each independently represents a hydrogen atom or a monovalent organic ^group, R 1 to R ⁶ are bonded to each other And a and b each represents an integer of 1 or more.)   2. The fullerene compound according to claim 1, which has a structure represented by the formula (I) in a range of 1 to 5 inclusive. In the formula (I), R ¹ and R ² each independently have an aliphatic group which may have a substituent, an aromatic group which may have a substituent, or a substituent. The fullerene compound according to claim 1, which is an alkoxy group which may be substituted or an aryloxy group which may have a substituent. In the formula (I), R ^{3 to} R ⁶ are each independently a hydrogen atom, a halogen atom, an aliphatic group which may have a substituent, or an aromatic group which may have a substituent. The fullerene compound according to any one of claims 1 to 3, wherein the fullerene compound is provided.   The fullerene compound according to any one of claims 1 to 4, wherein a sum of a and b is 2 or more and 3 or less.   A semiconductor device containing the fullerene compound according to any one of claims 1 to 5.   The semiconductor device according to claim 6, wherein the semiconductor device is a photoelectric conversion element, a field effect transistor, or an electroluminescence element.   A solar cell comprising the semiconductor device according to claim 7, which is a photoelectric conversion element.   A solar cell module comprising the solar cell according to claim 8.

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