JP7181774B2 - Compound and photoelectric conversion element - Google Patents

Description

TECHNICAL FIELD The present invention relates to a compound and a photoelectric conversion device using the compound.

A photoelectric conversion device is a device that includes at least a pair of electrodes including an anode and a cathode, and an active layer provided between the pair of electrodes. In a photoelectric conversion element, one of the electrodes is made of a transparent or semi-transparent material, and light is allowed to enter the active layer from the side of the transparent or semi-transparent electrode. Electric charges (holes and electrons) are generated in the active layer by the energy (hν) of light incident on the active layer, the generated holes move toward the anode, and the electrons move toward the cathode. Then, the charges that have reached the anode and cathode are taken out of the device.

A photoelectric conversion element that performs photoelectric conversion using light in the near-infrared wavelength region (wavelength 700 nm to 2500 nm) (hereinafter referred to as a near-infrared photoelectric conversion element) detects near-infrared light, which is invisible light. can be used as a near-infrared photodetector.

By using a near-infrared photoelectric conversion element as a near-infrared photodetector, information that cannot be obtained with the human eye can be obtained as an electric signal. And since the obtained electrical signal can be visualized by processing it with any suitable information processing technology, near-infrared photoelectric conversion can be applied to various fields such as 3D imaging and diagnosis based on biological information such as blood flow. Applications of conversion elements are expected (see, for example, Non-Patent Documents 1 and 2).

In addition, as a material for the active layer of a near-infrared photoelectric conversion element, an attempt has been made to develop a material that has strong absorption in the near-infrared region and relatively small absorption in the visible region and has low visible light absorption (patent Reference 1).

Japanese Patent Application Laid-Open No. 2008-308602

"One-shot measurement method of textured shape using near-infrared grid pattern" Image recognition and understanding symposium (MIRU2011) July 2011 P. 1494-1501. ``Visualization of living organisms using near-infrared rays,'' Medical Photonics No. 7 p. 53-57.

The photoelectric conversion element differs in the wavelength of light to be photoelectrically converted depending on the application of the mounted photodetector. For example, the photoelectric conversion element described in Patent Document 1 has a maximum absorption wavelength of 700 nm to 800 nm, but there are cases where a photoelectric conversion element having a maximum absorption wavelength of 800 nm or more is required. Further, like the photoelectric conversion element described in Patent Document 1, a photoelectric conversion element with low absorption in the visible light region may be required depending on the application of the photodetector. Further, there is a demand for improvement in characteristics that affect photodetection sensitivity, such as photoelectric conversion efficiency and dark current. In this way, the photoelectric conversion element and the material of the active layer applied thereto have characteristics (transmittance in the visible light range, absorption at a specific wavelength, photoelectric conversion efficiency and dark current) are sought.

（式（１）中、
Ｒ^１およびＲ^２は、それぞれ独立に、水素原子、置換基を有していてもよいアルキル基、置換基を有していてもよいハロゲン化アルキル基またはハロゲン原子を表す。複数存在するＲ^１は、同一であっても異なっていてもよく、複数存在するＲ^２は、同一であっても異なっていてもよい。ｍは、１～２０の整数を表す。複数存在するｍは、同一であっても異なっていてもよい。
Ａｒ^１は、環構造を構成する炭素原子がヘテロ原子で置換されていてもよい多環式芳香環のジイル基を表す。２個あるＡｒ^１は、同一であっても互いに異なっていてもよい。Ｃ^１、Ｃ^２およびＣ^３は、前記多環式芳香環のジイル基を構成する炭素原子を表す。
Ａｒ^２は、環構造を構成する炭素原子がヘテロ原子で置換されていてもよい多環式芳香環のジイル基を表す。
Ａｒ^１とＡｒ^２とは、互いに結合して環を構成していてもよい。）

（式（２）中、
Ｒ^１、Ｒ^２、ｍおよびＡｒ^１は、前記と同じ意味を表す。複数存在するＲ^１は、同一であっても異なっていてもよく、複数存在するＲ^２は、同一であっても異なっていてもよい。複数存在するｍは、同一であっても異なっていてもよい。
Ａは、置換基を有していてもよいアルキレン基、置換基を有していてもよいアリーレン基または置換基を有していてもよいヘテロアリーレン基を表す。２個あるＡは、同一であっても互いに異なっていてもよい。
Ａｒ^１とＡとは、互いに結合して環を構成していてもよい。）

（式（３）中、
Ｒ^１、Ｒ^２、ｍおよびＡｒ^１は、前記と同じ意味を表す。複数存在するＲ^１は、同一であっても異なっていてもよく、複数存在するＲ^２は、同一であっても異なっていてもよい。複数存在するｍは、同一であっても異なっていてもよい。Ａｒ^１とＡとは、互いに結合して環を構成していてもよい。）
［２］式（１）において２個あるＡｒ^１－（Ｒ^２）_ｍが互いに同一であり、２個ある－Ａｒ^２－Ｒ^１が互いに同一である請求項１記載の化合物、式（２）において２個あるＡｒ^１－（Ｒ^２）_ｍが互いに同一であり、２個ある－Ａ－Ｒ^１が互いに同一である請求項１記載の化合物または式（３）において２個あるＡｒ^１－（Ｒ^２）_ｍが互いに同一であり、２個ある－Ａ－Ｒ^１が互いに同一である、［１］に記載の化合物。
［３］陽極と、陰極と、該陽極と該陰極との間に設けられている活性層とを含み、該活性層が、［１］または［２］に記載の化合物を含む、光電変換素子。
［４］前記活性層が、ｐ型半導体材料およびｎ型半導体材料を含み、該ｐ型半導体材料が、［１］または［２］に記載の化合物である、［３］に記載の光電変換素子。
［５］前記ｎ型半導体材料が、フラーレンである、［４］に記載の光電変換素子。
［６］前記ｎ型半導体材料が、Ｃ６０フラーレンである、［５］に記載の光電変換素子。
［７］光検出素子である、［３］～［６］のいずれか１つに記載の光電変換素子。
［８］［７］に記載の光電変換素子を備える、イメージセンサー。 The present inventors have made intensive research to solve the above problems, and found that the above problems can be solved by a compound having a predetermined structure and a photoelectric conversion device using such a compound as a material for the active layer. The discovery led to the completion of the present invention. Accordingly, the present invention provides the following [1] to [8].
[1] A compound represented by the following formula (1), formula (2) or formula (3).

(In formula (1),
R ¹ and R ² each independently represent a hydrogen atom, an optionally substituted alkyl group, an optionally substituted halogenated alkyl group or a halogen atom. Multiple R ¹ 's may be the same or different, and multiple R ² 's may be the same or different. m represents an integer from 1 to 20; Multiple m may be the same or different.
Ar ¹ represents a polycyclic aromatic ring diyl group in which carbon atoms constituting the ring structure may be substituted with heteroatoms. Two Ar ¹ may be the same or different. C ¹ , C ² and C ³ represent carbon atoms constituting the diyl group of the polycyclic aromatic ring.
Ar ² represents a polycyclic aromatic ring diyl group in which carbon atoms constituting the ring structure may be substituted with heteroatoms.
Ar ¹ and Ar ² may combine with each other to form a ring. )

(In formula (2),
R ¹ , R ² , m and Ar ¹ have the same meanings as above. Multiple R ¹ 's may be the same or different, and multiple R ² 's may be the same or different. Multiple m may be the same or different.
A represents an optionally substituted alkylene group, an optionally substituted arylene group or an optionally substituted heteroarylene group. Two A's may be the same or different.
Ar ¹ and A may combine with each other to form a ring. )

(In formula (3),
R ¹ , R ² , m and Ar ¹ have the same meanings as above. Multiple R ¹ 's may be the same or different, and multiple R ² 's may be the same or different. Multiple m may be the same or different. Ar ¹ and A may combine with each other to form a ring. )
[2] The compound according to claim 1, wherein two Ar ¹ -(R ² ) _m in formula (1) are the same, and two -Ar ² -R ¹ are the same, the formula (2) wherein two Ar ¹ -(R ² ) _m are identical to each other and two -AR ¹ are identical to each other, or the compound according to claim 1, wherein two Ar ¹ -( The compound according to [1], wherein R ² ) _m are identical to each other, and the two —AR ¹ are identical to each other.
[3] A photoelectric conversion device comprising an anode, a cathode, and an active layer provided between the anode and the cathode, wherein the active layer contains the compound according to [1] or [2]. .
[4] The photoelectric conversion device according to [3], wherein the active layer contains a p-type semiconductor material and an n-type semiconductor material, and the p-type semiconductor material is the compound according to [1] or [2]. .
[5] The photoelectric conversion device according to [4], wherein the n-type semiconductor material is fullerene.
[6] The photoelectric conversion device according to [5], wherein the n-type semiconductor material is C60 fullerene.
[7] The photoelectric conversion element according to any one of [3] to [6], which is a photodetector.
[8] An image sensor comprising the photoelectric conversion element according to [7].

ADVANTAGE OF THE INVENTION According to this invention, the photoelectric conversion element which has the characteristic required for the use of the photodetector by which a near-infrared photoelectric conversion element is mounted, and the material used for this photoelectric conversion element can be provided.

FIG. 1 shows the solution absorption spectrum of compound P1-1 and the film absorption spectrum of compound P1-1. FIG. 2 shows the solution absorption spectrum of compound P5-1 and the film absorption spectrum of compound P5-1.

Preferred embodiments of the present invention are described in detail below. First, terms commonly used in the description of the present embodiment will be described.

A "hydrogen atom" may be either a protium atom or a deuterium atom.

"Optionally having a substituent" means that all hydrogen atoms constituting the compound or group are unsubstituted, and one or more hydrogen atoms are partially or entirely substituted by a substituent. Both aspects are included.

Examples of "substituents" include halogen atoms, alkyl groups, halogenated alkyl groups, aryl groups, arylalkyl groups, alkoxy groups, aryloxy groups, alkylthio groups, arylthio groups, monovalent heterocyclic groups, and substituted amino groups. , acyl groups, imine residues, amide groups, acid imide groups, substituted oxycarbonyl groups, alkenyl groups, alkynyl groups, cyano groups, and nitro groups.

A "halogen atom" includes a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

An "alkyl group" may be linear, branched, or cyclic, unless otherwise specified. The alkyl group may have a substituent. The number of carbon atoms in the linear alkyl group is generally 1-50, preferably 1-30, more preferably 1-20, not including the number of carbon atoms in the substituents. The number of carbon atoms in the branched or cyclic alkyl group is generally 3 to 50, preferably 3 to 30, more preferably 4 to 20, not including the number of carbon atoms in substituents.

Specific examples of alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isoamyl, 2-ethylbutyl, n- hexyl group, cyclohexyl group, n-heptyl group, cyclohexylmethyl group, cyclohexylethyl group, n-octyl group, 2-ethylhexyl group, 3-n-propylheptyl group, adamantyl group, n-decyl group, 3,7-dimethyl Alkyl groups such as octyl group, 2-ethyloctyl group, 2-n-hexyl-decyl group, n-dodecyl group, tetradecyl group, hexadecyl group, octadecyl group, eicosyl group, trifluoromethyl group, pentafluoroethyl group, per fluorobutyl group, perfluorohexyl group, perfluorooctyl group, 3-phenylpropyl group, 3-(4-methylphenyl)propyl group, 3-(3,5-di-n-hexylphenyl)propyl group, 6- An alkyl group having a substituent such as an ethyloxyhexyl group can be mentioned.

"Aryl group" means an atomic group remaining after removing one hydrogen atom directly bonded to a carbon atom constituting a ring from an optionally substituted aromatic hydrocarbon.

The aryl group may have a substituent. Specific examples of aryl groups include phenyl, 1-naphthyl, 2-naphthyl, 1-anthryl, 2-anthryl, 9-anthryl, 1-pyrenyl, 2-pyrenyl, and 4-pyrenyl groups. , 2-fluorenyl group, 3-fluorenyl group, 4-fluorenyl group, 2-phenylphenyl group, 3-phenylphenyl group, 4-phenylphenyl group, and these groups are alkyl groups, alkoxy groups, aryl groups, fluorine atoms groups having substituents such as

An "arylene group" means an atomic group remaining after removing two hydrogen atoms directly bonded to carbon atoms constituting a ring from an optionally substituted aromatic hydrocarbon.

An "alkoxy group" may be linear, branched, or cyclic. The number of carbon atoms in the linear alkoxy group is usually 1-40, preferably 1-10, not including the number of carbon atoms in the substituents. The number of carbon atoms in the branched or cyclic alkoxy group is usually 3-40, preferably 4-10, not including the number of carbon atoms in the substituents.

The alkoxy group may have a substituent. Specific examples of alkoxy groups include methoxy, ethoxy, n-propyloxy, isopropyloxy, n-butyloxy, isobutyloxy, tert-butyloxy, n-pentyloxy, n-hexyloxy, cyclohexyloxy, n-heptyloxy, n-octyloxy, 2-ethylhexyloxy, n-nonyloxy, n-decyloxy, 3,7-dimethyloctyloxy, and lauryloxy groups.

The number of carbon atoms in the "aryloxy group" is usually 6-60, preferably 6-48, not including the number of carbon atoms in the substituents.

The aryloxy group may have a substituent. Specific examples of the aryloxy group include a phenoxy group, a 1-naphthyloxy group, a 2-naphthyloxy group, a 1-anthryloxy group, a 9-anthryloxy group, a 1-pyrenyloxy group, and alkyl groups of these groups. , an alkoxy group, and a group having a substituent such as a fluorine atom.

The "alkylthio group" may be linear, branched, or cyclic. The number of carbon atoms in the straight-chain alkylthio group is generally 1-40, preferably 1-10, not including the number of carbon atoms in the substituents. The number of carbon atoms in the branched or cyclic alkylthio group is generally 3-40, preferably 4-10, not including the number of carbon atoms in the substituents.

The alkylthio group may have a substituent. Specific examples of alkylthio groups include methylthio, ethylthio, propylthio, isopropylthio, butylthio, isobutylthio, tert-butylthio, pentylthio, hexylthio, cyclohexylthio, heptylthio, octylthio, 2 -ethylhexylthio, nonylthio, decylthio, 3,7-dimethyloctylthio, laurylthio, and trifluoromethylthio groups.

The number of carbon atoms in the "arylthio group" is usually 6-60, preferably 6-48, not including the number of carbon atoms in the substituents.

The arylthio group may have a substituent. Examples of arylthio groups include a phenylthio group and a C1-C12 alkyloxyphenylthio group (where "C1-C12" indicates that the number of carbon atoms in the group immediately following it is 1-12. The same applies to other groups hereinafter.), C1-C12 alkylphenylthio groups, 1-naphthylthio groups, 2-naphthylthio groups, and pentafluorophenylthio groups.

The term "monovalent heterocyclic group" refers to the remaining atomic group excluding one hydrogen atom among the hydrogen atoms directly bonded to the carbon atoms or heteroatoms constituting the ring from the heterocyclic compound. means. The monovalent heterocyclic group includes a "monovalent aromatic heterocyclic group". "Monovalent aromatic heterocyclic group" refers to the remaining atoms of an aromatic heterocyclic compound excluding one hydrogen atom directly bonded to a carbon atom or heteroatom constituting a ring. means group. The monovalent heterocyclic group and monovalent aromatic heterocyclic group may have a substituent. Examples of heteroatoms include nitrogen, oxygen, sulfur, phosphorus, chlorine, iodine, and bromine atoms.

Examples of substituents that the monovalent heterocyclic group and the monovalent aromatic heterocyclic group may have include a halogen atom, an alkyl group, an aryl group, an alkoxy group, an aryloxy group, an alkylthio group, and an arylthio group. , monovalent heterocyclic groups, substituted amino groups, acyl groups, imine residues, amide groups, acid imide groups, substituted oxycarbonyl groups, alkenyl groups, alkynyl groups, cyano groups, and nitro groups.

Aromatic heterocyclic compounds include compounds in which an aromatic ring is condensed with a heterocyclic ring that does not exhibit aromaticity, in addition to a compound that exhibits aromaticity in itself.

Among aromatic heterocyclic compounds, specific examples of compounds in which the heterocycle itself exhibits aromaticity include oxadiazole, thiadiazole, thiazole, oxazole, thiophene, pyrrole, phosphole, furan, pyridine, pyrazine, pyrimidine, and triazine. , pyridazine, quinoline, isoquinoline, carbazole, and dibenzophosphole.

Among aromatic heterocyclic compounds, specific examples of compounds in which an aromatic ring is fused to a heterocyclic ring that does not exhibit aromaticity include phenoxazine, phenothiazine, dibenzoborole, dibenzosilole, and benzopyran. .

The number of carbon atoms in the monovalent heterocyclic group is usually 2-60, preferably 4-20, not including the number of carbon atoms in the substituents.

The monovalent heterocyclic group may have a substituent, and specific examples of the monovalent heterocyclic group include thienyl group, pyrrolyl group, furyl group, pyridyl group, benzofuryl group, and quinolyl group. , an isoquinolyl group, a pyrimidinyl group, a triazinyl group, and groups in which these groups have a substituent such as an alkyl group or an alkoxy group.

A "substituted amino group" means an amino group having a substituent. Examples of substituents that the substituted amino group can have include alkyl groups, aryl groups, and monovalent heterocyclic groups. Preferred substituents are alkyl groups, aryl groups, and monovalent heterocyclic groups. The substituted amino group usually has 2 to 30 carbon atoms.

Examples of substituted amino groups include dialkylamino groups such as dimethylamino group and diethylamino group, diphenylamino group, bis(4-methylphenyl)amino group, bis(4-tert-butylphenyl)amino group, bis(3, and diarylamino groups such as 5-di-tert-butylphenyl)amino group.

The "acyl group" usually has 2 to 20 carbon atoms, preferably 2 to 18 carbon atoms. Specific examples of acyl groups include acetyl, propionyl, butyryl, isobutyryl, pivaloyl, benzoyl, trifluoroacetyl, and pentafluorobenzoyl groups.

The term “imine residue” means an atomic group remaining after removing one hydrogen atom directly bonded to a carbon atom or a nitrogen atom constituting a carbon atom-nitrogen atom double bond from an imine compound. An "imine compound" means an organic compound having a carbon atom-nitrogen atom double bond in the molecule. Examples of imine compounds include aldimines, ketimines, and compounds in which a hydrogen atom bonded to a nitrogen atom constituting a carbon atom-nitrogen atom double bond in aldimines is substituted with an alkyl group or the like.

The imine residue usually has 2 to 20 carbon atoms, preferably 2 to 18 carbon atoms. Examples of imine residues include groups represented by the following structural formulas.

"Amido group" means an atomic group remaining after removing one hydrogen atom bonded to a nitrogen atom from amide. The amide group usually has 1 to 20 carbon atoms, preferably 1 to 18 carbon atoms. Specific examples of the amide group include a formamide group, an acetamide group, a propioamide group, a butyroamide group, a benzamide group, a trifluoroacetamide group, a pentafluorobenzamide group, a diformamide group, a diacetamide group, a dipropioamide group, a dibutyroamide group, and a dibenzamide group. , ditrifluoroacetamide groups, and dipentafluorobenzamide groups.

An "acid imide group" means an atomic group remaining after removing one hydrogen atom bonded to a nitrogen atom from an acid imide. The number of carbon atoms in the acid imide group is generally 4-20. Specific examples of acid imide groups include groups represented by the following structural formulas.

"Substituted oxycarbonyl group" means a group represented by R'-O-(C=O)-. Here, R' represents an alkyl group, an aryl group, an arylalkyl group, or a monovalent aromatic heterocyclic group.

The substituted oxycarbonyl group usually has 2 to 60 carbon atoms, preferably 2 to 48 carbon atoms.

Specific examples of substituted oxycarbonyl groups include a methoxycarbonyl group, an ethoxycarbonyl group, a propoxycarbonyl group, an isopropoxycarbonyl group, a butoxycarbonyl group, an isobutoxycarbonyl group, a tert-butoxycarbonyl group, a pentyloxycarbonyl group, and a hexyloxycarbonyl group. group, cyclohexyloxycarbonyl group, heptyloxycarbonyl group, octyloxycarbonyl group, 2-ethylhexyloxycarbonyl group, nonyloxycarbonyl group, decyloxycarbonyl group, 3,7-dimethyloctyloxycarbonyl group, dodecyloxycarbonyl group, tri fluoromethoxycarbonyl, pentafluoroethoxycarbonyl, perfluorobutoxycarbonyl, perfluorohexyloxycarbonyl, perfluorooctyloxycarbonyl, phenoxycarbonyl, naphthoxycarbonyl, and pyridyloxycarbonyl groups.

An "alkenyl group" may be linear, branched, or cyclic. The number of carbon atoms in the straight-chain alkenyl group is usually 2-30, preferably 3-20, not including the number of carbon atoms in the substituents. The number of carbon atoms in the branched or cyclic alkenyl group is usually 3 to 30, preferably 4 to 20, not including the number of carbon atoms in substituents.

The alkenyl group may have a substituent. Specific examples of alkenyl groups include vinyl, 1-propenyl, 2-propenyl, 2-butenyl, 3-butenyl, 3-pentenyl, 4-pentenyl, 1-hexenyl and 5-hexenyl groups. , 7-octenyl groups, and groups in which these groups have substituents such as alkyl groups and alkoxy groups.

An "alkynyl group" may be linear, branched, or cyclic. The number of carbon atoms in the linear alkenyl group is usually 2 to 20, preferably 3 to 20, not including the number of carbon atoms in the substituents. The number of carbon atoms in the branched or cyclic alkenyl group is generally 4 to 30, preferably 4 to 20, not including the number of carbon atoms in substituents.

The alkynyl group may have a substituent. Specific examples of alkynyl groups include ethynyl, 1-propynyl, 2-propynyl, 2-butynyl, 3-butynyl, 3-pentynyl, 4-pentynyl, 1-hexynyl and 5-hexynyl groups. , and groups in which these groups have a substituent such as an alkyl group or an alkoxy group.

<Compound>
The compound of the present embodiment contains a squaric acid (squaric acid) type or pentanoic acid (croconic acid) type mother core structure, and is a compound in which two condensed ring structures containing a nitrogen atom are bound to this mother core structure. is. These two condensed ring structures preferably have the same structure from the viewpoint of easier production.

The compound of this embodiment has a maximum absorption wavelength (λmax) in the near-infrared wavelength region.

Examples of the compound of this embodiment include compounds represented by the following formula (1). The compound represented by formula (1) has syn- and anti-isomers, and any of them may be used.

Here, the components that can be included in formula (1) will be described.
R ¹ and R ² each independently represent a hydrogen atom, an optionally substituted alkyl group, an optionally substituted halogenated alkyl group or a halogen atom. Multiple R ¹ 's may be the same or different, and multiple R ² 's may be the same or different. m represents an integer from 1 to 20; Multiple m may be the same or different.
R ¹ and R ² are hydrogen atom, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonanyl group, decyl group, trifluoromethyl group, trichloromethyl group, chloro It is preferably a methyl group, bromomethyl group, iodomethyl group, fluorine atom, chlorine atom, bromine atom or iodine atom, hydrogen atom, methyl group, ethyl group, propyl group, butyl group, trifluoromethyl group, fluorine atom, chlorine Atoms are more preferred.
m is preferably an integer of 1 to 10, more preferably an integer of 1 to 5, even more preferably 1.

Ar ¹ represents a polycyclic aromatic ring diyl group in which carbon atoms constituting the ring structure may be substituted with heteroatoms. Two Ar ¹ may be the same or different. Two Ar ¹ are preferably the same.
The polycyclic aromatic diyl group in which the carbon atoms constituting the ring structure may be substituted with heteroatoms, for example, a naphthalenediyl group in which the carbon atoms constituting the ring structure may be substituted with heteroatoms , an anthracenediyl group and a phenanthenediyl group in which the carbon atoms constituting the ring structure may be substituted with heteroatoms, naphthalenediyl groups in which the carbon atoms constituting the ring structure may be substituted with heteroatoms, and An anthracenediyl group in which the carbon atoms constituting the ring structure may be substituted with heteroatoms is preferred.
Heteroatoms include, for example, a nitrogen atom, an oxygen atom, a sulfur atom, and a phosphorus atom.

Two Ar ¹ are preferably a diyl group of a polycyclic aromatic ring in which the carbon atoms constituting the ring structure may be substituted with hetero atoms, and both the carbon atoms constituting the ring structure are It is preferably a naphthalenediyl group which may be substituted with a hetero atom or an anthracenediyl group in which any of the carbon atoms constituting the ring structure may be substituted with a hetero atom, and is a naphthalenediyl group or an anthracenediyl group. is more preferable.

C ¹ , C ² and C ³ represent carbon atoms constituting a diyl group of a polycyclic aromatic ring in which the carbon atoms constituting the ring structure may be substituted with heteroatoms.

Here, for example, two C ² independently constitute the carbon atom at the 4a-position or the 8a-position of a naphthalenediyl group in which the carbon atoms constituting the structure may be substituted with a hetero atom, or the structure The carbon atom is the carbon atom at the 4a-, 8a-, 9a- or 10a-position of the anthracenediyl group which may be substituted with a heteroatom.

The two ^C2s are preferably carbon atoms contained in the same group and having the same carbon position number.

Ar ² represents a polycyclic aromatic ring diyl group in which carbon atoms constituting the ring structure may be substituted with heteroatoms.

Specific examples of Ar ² include benzenediyl, naphthalenediyl, thiophenediyl, pyridinediyl, imidazolidinediyl, pyridiminediyl, and 1,3,5-triazinediyl groups.

Ar ¹ and Ar ² may combine with each other to form a ring.

As the compound represented by formula (1), a compound in which two Ar ¹ —(R ² ) _m are the same and two —Ar ² —R ¹ are the same is preferred.

Specific examples of the compound represented by formula (1) include compounds P1-1 to P1-24 represented by the following formulas.

Compounds P1-1 to P1-4 and compounds P1-17 to P1-20 are preferred as the formula (1) from the viewpoint of ease of synthesis, and compound P1-1 and compounds P1-17 to P1-20. is more preferred.

Compound P1-1 has a maximum absorption wavelength (λmax) of 894 nm in a solution state, and a maximum absorption wavelength of 791 nm when formed into a thin film.

Examples of the compound of this embodiment include compounds represented by the following formula (2). The compound represented by formula (2) has syn- and anti-isomers, and any of them may be used.

Here, the components that can be included in formula (2) will be described.
R ¹ , R ² , m, Ar ¹ , C ¹ , C ² and C ³ are as defined above.
A represents an optionally substituted alkylene group, an optionally substituted arylene group or an optionally substituted heteroarylene group. Two A's may be the same or different.

Specific examples of A include an alkylene group having 1 to 20 carbon atoms, a phenylene group, a naphthylene group, a thiophenylene group, a naphthylene group, a thiophenylene group, a pyridylene group, and a 1,3,5-triazylylene group. A is preferably an alkylene group having 2 to 12 carbon atoms.

Examples of the alkylene group optionally having a substituent include methylene group, ethylene group, propanediyl group, butanediyl group, pentanediyl group, hexanediyl group, heptanediyl group, octanediyl group, nonanediyl group, decanediyl group, and undecane. diyl, dodecanediyl, methylethylene, methylpropanediyl and dimethylmethylene, ethylene, propanediyl, butanediyl, pentanediyl, hexanediyl, heptanediyl, octanediyl, nonanediyl, decanediyl; preferably an ethylene group, a propanediyl group, a butanediyl group, a pentanediyl group, a hexanediyl group, a heptanediyl group, an octanediyl group, a nonanediyl group, and a decanediyl group; It is more preferable to have

Ar ¹ and A may combine with each other to form a ring. Examples of such ring structures include structures represented by the following formulas.

The compound represented by formula (2) is preferably a compound in which two Ar ¹ —(R ² ) _m are the same and two —AR ¹ are the same.

Specific examples of the compounds represented by formula (2) include compounds P2-1 to P2-24 and compounds P3-1 to P3-16 represented by the following formulas.

From the viewpoint of ease of synthesis, the compounds of formula (2) are compounds P2-1 to P2-4, compound P2-13, compounds P2-17 to P2-20, and compounds P3-1 to P3-10. are preferred, and compound P2-1 and compound P3-1 are more preferred.

Examples of the compound of this embodiment include compounds represented by the following formula (3). Formula (2) has syn- and anti-isomers, and any of them may be used.

Here, the components that can be included in formula (3) will be described.
R ¹ , R ² , Ar ¹ , m, C ¹ , C ² , C ³ , and A are as defined above.
Ar ¹ and A may combine with each other to form a ring. Examples of such ring structures include structures represented by the following formulas.

As the compound represented by formula (3), a compound in which two Ar ¹ —(R ² ) _m are the same and two —AR ¹ are the same is preferred.

Specific examples of the compounds represented by formula (3) include compounds P4-1 to P4-24 and compounds P5-1 to P5-9 represented by the following formulas.

From the viewpoint of ease of synthesis, the formula (3) includes compounds P4-1 to P4-4, compound P4-13, compounds P4-17 to P4-20, compounds P5-1 to P5-4, and compound P5. -6 and compound P5-9 are preferred, and compound P4-1 and compound P5-1 are more preferred.

In the near-infrared wavelength region, the compound of the present embodiment preferably exhibits high absorption in the wavelength range of 800 nm to 1200 nm, and more preferably exhibits high absorption in the wavelength range of 850 nm to 1100 nm. The compound of the present embodiment preferably has high transmittance of light in the visible light wavelength range.

<Method for producing compound>
The compound of this embodiment is disclosed in, for example, ACS Appl. Mater. Interfaces 2018, 10, 11063-11069. It can be manufactured (synthesized) with reference to the manufacturing method described in . Specifically, an N-substituted naphtholactam compound can be synthesized and used for manufacturing. Hereinafter, the method for producing the compound of the present embodiment will be described more specifically.

(1) Compounds represented by the above formulas (2) and (3) in which the group represented by —AR ¹ is an alkyl group (for example, compound P3-1) can be prepared by the following scheme. can be manufactured according to Here, the method for producing compound P3-1 will be described as an example.

Specifically, first, an ordinary alkylation reaction can be used to synthesize the N-alkylnaphtholactam compound.

For example, benz[cd]indol-2-one can be N-alkylated by heat treatment in the presence of a bromoalkane and a base in an aprotic solvent.

Examples of bases that can be used include inorganic bases such as sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate. Additives such as N,N-dimethylaminopyridine can also be used to accelerate the reaction.

Next, the obtained N-alkylnaphtholactam compound is reacted with a Grignard reagent such as methylmagnesium halide in an ether solvent, added dropwise to ice water containing hydrochloric acid, and filtered after distilling off the ether solvent. An aqueous hydrochloride solution can be obtained by removing the precipitate.

Examples of ether solvents that can be used include tetrahydrofuran and diethyl ether.

Next, the resulting hydrochloride aqueous solution is added dropwise to a potassium iodide aqueous solution for ion exchange, whereby an iodonium salt can be obtained. If the iodonium salt precipitates, it can be removed by filtration. Furthermore, the obtained precipitate is preferably washed with ion-exchanged water and ethyl acetate.

Compound P3-1 (compound according to the present embodiment) can be obtained by subjecting the obtained iodonium salt to dehydration condensation with croconic acid (pentanoic acid) (or squaric acid (squaric acid)).

Since two molecules of iodonium salt are dehydrated and condensed with respect to one molecule of croconic acid (pentagonal acid) or squaric acid (squaric acid), the amount of iodonium salt is 1.5 to 5.0 times the molar amount of croconic acid or squaric acid. It is preferably used, more preferably in a 1.8- to 3.0-fold molar amount.

Dehydration condensation is preferably carried out under heating conditions, and the reaction temperature is preferably 80°C to 150°C, more preferably 90°C to 130°C.

It is preferable to use a mixed solvent of an alcoholic solvent and an aromatic solvent because it facilitates ensuring the solubility of the iodonium salt, croconic acid (pentanoic acid) or squaric acid (squaric acid). From the viewpoint of ease of removal by distillation under reduced pressure, preferred alcoholic solvents include methanol, ethanol, propanol, butanol, and pentanol, and preferred aromatic solvents include benzene, toluene, xylene, and chlorobenzene.

After completion of the reaction, the reaction solvent is distilled off under reduced pressure, and the residue is dissolved in an alcoholic solvent and recrystallized to obtain compound P3-1 (the compound of the present embodiment). Examples of alcoholic solvents include methanol, ethanol, propanol and butanol.

(2) A compound represented by the above formula (1) in which the group represented by —Ar ² —R ¹ is an aryl group (for example, compound P1-1) is produced according to the following scheme. be able to. Here, the method for producing compound P1-1 will be described as an example.

Specifically, first, in synthesizing an N-arylnaphtholactam compound, for example, N-phenylnaphthylamine is lithiated by treating it with n-butyllithium in an ether solvent, and then reacted with carbon dioxide. Thus, a mixture of the N-phenyl-substituted N-arylnaphtholactam compound and the aminocarboxylic acid compound can be obtained.

Tetrahydrofuran, diethyl ether, etc. can be used as the ether solvent.

Then, by heat-treating the mixture obtained by distilling off the solvent, it is possible to converge on the N-arylnaphtholactam compound. The reaction temperature is preferably 130°C to 200°C.

Thereafter, compound P1-1 according to the present embodiment is obtained in the same manner except that the obtained N-arylnaphtholactam compound is used in place of the N-alkylnaphtholactam compound in the production method according to (1) above. can be done.

<Photoelectric conversion element>
The photoelectric conversion element of this embodiment includes an anode, a cathode, and an active layer provided between the anode and the cathode, wherein the active layer is represented by formula (1), formula (2), or formula (3) It is a photoelectric conversion element containing a compound represented by.

The photoelectric conversion element of this embodiment is a near-infrared photoelectric conversion element having strong absorption in the near-infrared wavelength region (wavelength 700 nm to 2500 nm).

In the photoelectric conversion device of the present embodiment, since the active layer contains the compound represented by formula (1), formula (2) or formula (3), in the near-infrared wavelength region, preferably at a wavelength of 800 nm to 1200 nm It has high photoelectric conversion efficiency, more preferably at a wavelength of 850 nm to 1100 nm. Since the compound represented by Formula (1), Formula (2), or Formula (3) can transmit light in the visible wavelength range, the photoelectric conversion element of the present embodiment can transmit light in the visible wavelength range. It is possible to effectively detect light in the near-infrared wavelength region while reducing the signal based on.

Here, the constituent elements that the photoelectric conversion element of this embodiment can have will be described.
(substrate)
A photoelectric conversion element is usually provided on a substrate (support substrate). Electrodes, including cathodes and anodes, may be formed on the substrate. A mode in which the anode is arranged so as to be bonded to the support substrate is called a forward lamination structure, and a mode in which the cathode is arranged so as to be bonded to the support substrate is called a reverse lamination structure. The photoelectric conversion element of this embodiment can take any form.

The material of the substrate is not particularly limited as long as it is a material that does not chemically change when the layer containing the organic compound is formed. Materials for the substrate include, for example, glass, plastic, polymer film, and silicon. In the case of an opaque substrate, it is preferable that the electrode on the side opposite to the electrode provided on the opaque substrate side (that is, the electrode on the far side from the substrate) be a transparent or translucent electrode.

(electrode)
Materials for transparent or translucent electrodes include, for example, conductive metal oxide films and semitransparent metal thin films. Specifically, indium oxide, zinc oxide, tin oxide, and their composites indium tin oxide (ITO), indium zinc oxide (IZO), conductive materials such as NESA, gold, platinum, silver, and copper. mentioned. ITO, IZO, and tin oxide are preferable as materials for transparent or translucent electrodes. Moreover, as the electrode, a transparent conductive film using an organic compound such as polyaniline and its derivatives, polythiophene and its derivatives as a material may be used. Transparent or translucent electrodes include dispersions such as emulsions, suspensions, and metal pastes containing nanoparticles of conductive materials, nanowires of conductive materials, or nanotubes of conductive materials. Alternatively, it may be formed by a coating method using a molten low melting point metal or the like. Examples of conductive substances include metals such as gold and silver, oxides such as ITO (indium tin oxide), carbon nanotubes, and the like. The electrode has a structure in which nanoparticles or nanofibers of a conductive substance are dispersed and arranged in a predetermined medium such as a conductive polymer, as described in Japanese Patent Application Publication No. 2010-525526. may be
The transparent or translucent electrode can be either the anode or the cathode. Further, the electrode provided so as to be bonded to the substrate (supporting substrate) may be either an anode or a cathode. If both electrodes are transparent, it is possible to obtain a photoelectric conversion element with high transmittance of light in the visible light wavelength range.

If one electrode is transparent or translucent, the other electrode may be an electrode with low light transmission. Materials for electrodes with low light transmittance include, for example, metals and conductive polymers. Specific examples of low light transmissive electrode materials include lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, strontium, barium, aluminum, scandium, vanadium, zinc, yttrium, indium, cerium, samarium, europium, Metals such as terbium, ytterbium, and alloys of two or more thereof, or one or more of these metals together with gold, silver, platinum, copper, manganese, titanium, cobalt, nickel, tungsten and tin alloys with one or more metals selected from the group consisting of graphite, graphite intercalation compounds, polyaniline and its derivatives, polythiophene and its derivatives. Alloys include magnesium-silver alloys, magnesium-indium alloys, magnesium-aluminum alloys, indium-silver alloys, lithium-aluminum alloys, lithium-magnesium alloys, lithium-indium alloys, and calcium-aluminum alloys.

(active layer)
In the photoelectric conversion device of this embodiment, the active layer contains a p-type semiconductor material (electron-donating compound) and an n-type semiconductor material (electron-accepting compound), and the p-type semiconductor material is represented by formula (1), formula (2) or a compound represented by formula (3).

The active layer can take the form of a single layer or a laminate of multiple layers. The monolayer active layer contains an electron-accepting compound (n-type semiconductor material) and an electron-donating compound (p-type semiconductor material).

In the p-type semiconductor material and the n-type semiconductor material that the active layer may contain, which of the p-type semiconductor material and the n-type semiconductor material is relative to the HOMO or LUMO energy levels of the selected compounds. can be determined to

The active layer in which a plurality of layers are laminated is composed of, for example, a laminate obtained by laminating a first semiconductor layer containing a p-type semiconductor material and a second semiconductor layer containing an n-type semiconductor material. In this case, the first semiconductor layer is arranged closer to the anode than the second semiconductor layer.

The n-type semiconductor material used as the material for the active layer is not particularly limited, provided that it can be applied to the active layer forming process described below.

As the n-type semiconductor material, one or more selected from fullerenes and fullerene derivatives is preferable. In particular, when the active layer is formed by a vapor deposition method, it is preferable to use fullerene, and when it is formed by a coating method, it is preferable to use a fullerene derivative.

Examples of fullerenes include C60 fullerene, C70 fullerene, C76 fullerene, C78 fullerene, and C84 fullerene. Examples of fullerene derivatives include derivatives of these fullerenes. A fullerene derivative means a compound in which at least a part of fullerene is modified.

Examples of fullerene derivatives include compounds represented by the following formulas (N-1) to (N-4).

In formulas (N-1) to (N-4), R ^a represents an alkyl group, an aryl group, a monovalent heterocyclic group, or a group having an ester structure. A plurality of R ^a may be the same or different.

^Rb represents an alkyl group or an aryl group. A plurality of R ^b may be the same or different.

Examples of groups having an ester structure represented by R ^a include groups represented by the following formula (19).

In formula (19), u1 represents an integer of 1-6. u2 represents an integer from 0 to 6; R ^c represents an alkyl group, an aryl group, or a monovalent heterocyclic group.

Examples of C60 fullerene derivatives include the following compounds.

Examples of C70 fullerene derivatives include the following compounds.

Specific examples of fullerene derivatives include [6,6]-phenyl-C61 butyric acid methyl ester (C60PCBM, [6,6]-Phenyl C61 butyric acid methyl ester), [6,6]-phenyl-C71 butyric acid methyl ester ( C70PCBM, [6,6]-Phenyl C71 butyric acid methyl ester), [6,6"-phenyl-C85 butyric acid methyl ester (C84PCBM, [6,6]-Phenyl C85 butyric acid methyl ester), and [6,6 ]-Thienyl-C61 butyric acid methyl ester ([6,6]-Thienyl C61 butyric acid methyl ester).

The thickness of the active layer is generally preferably 1 nm to 100 μm, more preferably 2 nm to 1000 nm, even more preferably 5 nm to 500 nm, and particularly preferably 20 nm to 200 nm. When the photoelectric conversion element is, for example, a solar cell, the thickness of the active layer is preferably 500 nm to 1000 nm. When the photoelectric conversion element is, for example, a photodetection element, the thickness of the active layer is preferably 500 nm to 1000 nm.

(middle layer)
The photoelectric conversion element of the present embodiment includes additional components such as a charge transport layer (electron transport layer, hole transport layer, electron injection layer, hole injection layer) as further components for improving characteristics such as photoelectric conversion efficiency. An intermediate layer may be provided.

As a material used for such an intermediate layer, any suitable conventionally known material can be used. Materials for the intermediate layer include, for example, alkali metal or alkaline earth metal halides, such as lithium fluoride, and oxides.

Materials used for the intermediate layer include fine particles of inorganic semiconductors such as titanium oxide, and PEDOT (poly(3,4-ethylenedioxythiophene)) and PSS (poly(4-styrenesulfonate)). A mixture (PEDOT:PSS) may be mentioned.

The photoelectric conversion element of this embodiment may have a hole transport layer between the anode and the active layer. The hole transport layer has a function of transporting holes from the active layer to the electrode.

A hole-transporting layer provided in contact with an anode may be particularly referred to as a hole-injecting layer. A hole transport layer (hole injection layer) provided in contact with the anode has a function of promoting injection of holes into the anode. The hole transport layer (hole injection layer) may be in contact with the active layer.

The hole-transporting layer contains a hole-transporting material. Examples of hole-transporting materials include polythiophene and its derivatives, aromatic amine compounds, polymeric compounds containing constitutional units having aromatic amine residues, CuSCN, CuI, NiO, and molybdenum oxide ( _MoO3 ). be done.

The photoelectric conversion device of this embodiment may have an electron transport layer between the cathode and the active layer. The electron transport layer has a function of transporting electrons from the active layer to the cathode. The electron transport layer may be in contact with the cathode. The electron transport layer may be in contact with the active layer.

The electron-transporting layer contains an electron-transporting material. Examples of electron-transporting materials include nanoparticles of zinc oxide, nanoparticles of gallium-doped zinc oxide, nanoparticles of aluminum-doped zinc oxide, and polyalkyleneimine as the backbone, with ethylene oxide attached to nitrogen atoms in the backbone. ethoxylated polyethylenimine (PEIE), which is a modified variant, and PFN-P2.

(sealing layer)
The photoelectric conversion element may contain a sealing layer. The sealing layer can be provided, for example, on the side of the electrode farther from the substrate. The sealing layer can be formed of a material having a property of blocking moisture (water vapor barrier property) or a property of blocking oxygen (oxygen barrier property).

(Use of photoelectric conversion element)
The photoelectric conversion element of the present embodiment can pass a photocurrent by irradiating light from the transparent or translucent electrode side in a state where a voltage is applied between the electrodes, and can be used as a light detection element (photosensor). can be operated. Moreover, it can also be used as an image sensor by integrating a plurality of optical sensors.

Moreover, the photoelectric conversion element of this embodiment can generate a photovoltaic force between the electrodes by being irradiated with light, and can be operated as a solar cell. A thin-film solar cell module can also be obtained by integrating a plurality of solar cells.

(Application example of photoelectric conversion element)
The photoelectric conversion device according to the present embodiment has a large absorption in the near-infrared wavelength region, and a small absorption in the visible wavelength region. Since the compound is used as the material for the active layer, it is useful as a near-infrared photodetector.

The photoelectric conversion element of the present embodiment can be suitably used as a photodetector, an imaging element, and an image sensor applied to devices for 3D imaging, VR (virtual reality), augmented reality (AR), and MR (mixed reality). can be done.

<Method for producing photoelectric conversion element>
The method for manufacturing the photoelectric conversion element of this embodiment is not particularly limited. The photoelectric conversion element of this embodiment can be manufactured by a forming method suitable for the materials selected for forming the constituent elements already described.

(Method of forming electrodes)
As a method for forming the electrodes, any suitable conventionally known forming method can be used. Methods of forming electrodes include, for example, a vacuum deposition method, a sputtering method, an ion plating method, and a plating method.

(Method for forming intermediate layer)
A method for manufacturing the intermediate layer is not particularly limited. When the intermediate layer is composed of the already-described inorganic material or low-molecular-weight material, it can be formed by any suitable method, such as a vacuum vapor deposition method or a vacuum heating vapor deposition method, depending on the material.

Further, when the functional layer such as the intermediate layer of the photoelectric conversion element of the present embodiment is composed of a material soluble in a solvent, particularly a polymer compound, it can be produced by a coating method using ink.

The coating method applied in the method for producing a photoelectric conversion element of the present embodiment includes a step (i) of obtaining a coating film by applying an ink containing a material and a solvent to an object to be coated, and removing the solvent from the coating film. and step (ii). Steps (i) and (ii) included in the coating method will be described below.

step (i)
Any suitable coating method can be used as a method for applying the ink to the coating object. The coating method is preferably a slit coating method, a knife coating method, a spin coating method, a micro gravure coating method, a gravure coating method, a bar coating method, an inkjet printing method, a nozzle coating method, or a capillary coating method. A coating method, a capillary coating method, or a bar coating method is more preferable, and a slit coating method or a spin coating method is even more preferable.

The ink is applied to an application target selected according to the photoelectric conversion element and its manufacturing method. The ink can be applied onto the substrate or the functional layer of the photoelectric conversion element in the manufacturing process of the photoelectric conversion element. Therefore, the ink application target differs depending on the layer structure and the order of layer formation of the photoelectric conversion element to be manufactured. For example, when the photoelectric conversion element has a layer structure of substrate/anode/hole transport layer/active layer/electron transport layer/cathode, and the layer described further to the left is formed first (forward lamination structure), and when the hole transport layer is formed by a coating method, the object to be coated with the ink is the anode. Further, for example, when the photoelectric conversion element has a layer structure of substrate/cathode/electron transport layer/active layer/hole transport layer/anode, and the layer described further to the left is formed first ( When the hole transport layer is formed by a coating method, the ink is applied to the active layer.

step (ii)
Any suitable method can be used as a method for removing the solvent from the coating film of the ink, that is, as a method for removing the solvent from the coating film to form a solidified film. Examples of methods for removing the solvent include drying methods such as direct heating using a hot plate, hot air drying, infrared heat drying, flash lamp annealing drying, and vacuum drying.

The step of forming the functional layer by the coating method may include other steps in addition to the steps (i) and (ii) provided that the objects and effects of the present invention are not impaired.

The ink used in the ink coating method may be a solution, or may be a dispersion liquid such as a dispersion liquid, an emulsion (emulsion), or a suspension (suspension). The ink of this embodiment is an ink for forming a predetermined functional layer, and may contain a selected functional material (p-type semiconductor material and/or n-type semiconductor material) and a solvent.

The solvent should be selected in consideration of the solubility of the selected material and the characteristics (boiling point, etc.) for coping with the drying conditions.
The solvent preferably contains an aromatic hydrocarbon (hereinafter simply referred to as aromatic hydrocarbon) optionally having a substituent (eg, alkyl group, halogen atom).

Examples of such aromatic hydrocarbons include toluene, xylene (eg, o-xylene, m-xylene, p-xylene), trimethylbenzene (eg, mesitylene, 1,2,4-trimethylbenzene (pseudocumene)). , butylbenzene (eg n-butylbenzene, sec-butylbenzene, tert-butylbenzene), methylnaphthalene (eg 1-methylnaphthalene), tetralin, indane, chlorobenzene and dichlorobenzene (o-dichlorobenzene). .

The solvent may contain only one aromatic hydrocarbon, or may contain two or more aromatic hydrocarbons. Preferably, the solvent contains only one aromatic hydrocarbon.

Solvents are preferably toluene, o-xylene, m-xylene, p-xylene, mesitylene, pseudocumene, n-butylbenzene, sec-butylbenzene, tert-butylbenzene, methylnaphthalene, tetralin, indane, chlorobenzene and o-xylene. It contains one or more selected from the group consisting of dichlorobenzene, more preferably o-xylene, pseudocumene, tetralin, chlorobenzene or o-dichlorobenzene.

The solvent may further contain a solvent other than aromatic hydrocarbons. Examples of such solvents include ketone solvents such as acetone, methyl ethyl ketone, cyclohexanone, acetophenone, and propiophenone, ethyl acetate, butyl acetate, phenyl acetate, ethyl cellosolve acetate, methyl benzoate, butyl benzoate, and benzyl benzoate. and other ester solvents.

In addition to a solvent, a p-type semiconductor material, and an n-type semiconductor material, the ink contains an ultraviolet absorber, an antioxidant, and a sensitizer to generate electric charges by absorbed light, as long as the objects and effects of the present invention are not impaired. Optional ingredients such as sensitizers to increase stability and light stabilizers to increase UV stability may also be included.

Preparation of Ink The ink can be prepared by a known method. For example, it can be prepared by mixing selected multiple types of solvents to prepare a mixed solvent, adding and mixing the materials already described to the mixed solvent, and dissolving or dispersing the materials. The solvent and material may be heated and mixed at a temperature below the boiling point of the solvent.

After mixing the solvent and materials, the resulting mixture may be filtered using a filter and the obtained filtrate may be used as an ink. As the filter, for example, a filter made of a fluororesin such as polytetrafluoroethylene (PTFE) can be used.

(Method of forming active layer)
The active layer of the photoelectric conversion device of the present embodiment is manufactured using a compound represented by formula (1), formula (2), or formula (3) as the p-type semiconductor material and fullerene as the n-type semiconductor material. preferably.

As a method for forming the active layer, any suitable conventionally known forming method can be used. The active layer may be formed by a coating method similar to the method for forming the intermediate layer already described.

Suitable methods for forming the active layer of the present embodiment, which is formed using the materials already described, include, for example, a vacuum deposition method such as a resistance heating deposition method and an electron beam heating deposition method. More specifically, the active layer of the photoelectric conversion element of the present embodiment uses a compound represented by formula (1), formula (2) or formula (3) and fullerene, and these materials are simultaneously vacuum-deposited. It is preferably formed by a co-evaporation method or a flash evaporation method.

Examples of the present invention will be described below. The invention is not limited to the following examples.

(I) NMR analysis NMR measurement was performed using a sample in which the compound to be measured was dissolved in deuterated chloroform, using an NMR device (400 MHz NMR device manufactured by JEOL, JNM-ECZ400S/L1).
(II) UV-vis absorption spectrum analysis 5 mg of the compound to be measured was dissolved in 0.995 g of chloroform to obtain solution I. A mixed solution II was obtained by mixing 0.16 g of the resulting solution and 0.84 g of chloroform. A mixed solution III obtained by mixing 0.1 g of the obtained mixed solution I and 4.9 g of chloroform was used as a measurement solution.
The absorption spectrum of the measurement solution was measured from 300 to 1200 nm using a measurement device (Cary 5E UV-VIS-NIR Spectrophotometer manufactured by Varian). The spectrum obtained is called a solution absorption spectrum.
A film of the solution I was formed on a glass substrate by spin coating to obtain a measurement sample. The absorption spectrum of the measurement sample was measured from 300 to 1200 nm using a measurement device (Cary 5E UV-VIS-NIR Spectrophotometer manufactured by Varian). The obtained spectrum is called a deposition absorption spectrum.

<Synthesis Example 1> Synthesis of compound P1-1 (a) Synthesis of 1-phenyl-(1H)-benz[cd]indol-2-one according to the following scheme: 1-phenyl-(1H)-benz[cd] Indol-2-ones were synthesized.

Under a nitrogen gas atmosphere, 7.13 g (32.5 mmol) of N-phenyl-1-naphthylamine was dissolved in 260 mL of dehydrated diethyl ether to obtain a solution.

The resulting solution was ice-cooled to 0° C., and 100 mL of a 2.6 M hexane solution of n-butyllithium (manufactured by Kanto Kagaku, containing 260 mmol of n-butyllithium) was added dropwise over 20 minutes. A mixture was obtained by mixing.

The resulting mixture was heated to 20° C. and stirred for 3 hours to carry out lithiation treatment.

Next, the lithiated reaction solution was transferred to a large excess of dry ice under a nitrogen gas atmosphere to carry out a carboxylation treatment.

The carboxylated reaction solution was ice-cooled and neutralized to pH 4-5 with 2N hydrochloric acid.

The neutralized reaction solution was extracted with 400 mL of ethyl acetate, dried over sodium sulfate, and filtered. Ethyl acetate was distilled off under reduced pressure to obtain a slurry.

The resulting slurry was heated at 170° C. for 2 hours under a nitrogen gas atmosphere. Then, the solid was obtained by standing to cool and returning to normal temperature.

The resulting solid was purified by recrystallization using a mixed solvent of hexane and toluene (mixture ratio: 3/1) to give N-phenyl-(1H)-benz[cd]indol-2-one. 34 g (25.9 mmol, 79.5% yield) were obtained. The results of ¹ H-NMR are shown below.

¹ H-NMR (ppm, CDCl ₃ ): 8.17 (d, 1H), 8.09 (d, 1H), 7.78 (t, 1H), 7.64-7.38ppm (m, 7H) , 7.03(d, 1H).

(b) Synthesis of 2-methyl-1-phenyl-(1H)-benz[cd]indolium iodide Synthesis of 2-methyl-1-phenyl-(1H)-benz[cd]indolium iodide according to the following scheme did.

Under a nitrogen gas atmosphere, 1.22 g (5.0 mmol) of N-phenyl-(1H)-benz[cd]indol-2-one was dissolved in 4.6 mL of dehydrated tetrahydrofuran to obtain a solution.
To the resulting solution, 12.8 mL of a 1.0 M tetrahydrofuran solution of methylmagnesium chloride (12.8 mmol) was added dropwise over 10 minutes at 23°C. The obtained reaction solution was heated to 55° C. and stirred for 2 hours.
Next, the reaction solution was added dropwise to a diluted solution obtained by diluting 1.9 mL of concentrated hydrochloric acid with 23 mL of ice water. After tetrahydrofuran was distilled off under reduced pressure, the precipitate was filtered to obtain a filtrate.

The obtained filtrate was transferred to a solution prepared by dissolving 1.66 g (10.0 mmol) of potassium iodide in 23 mL of deionized water to obtain a reddish-brown suspension. 2-Methyl-1-phenyl-(1H)-benz[cd ] 0.444 g (1.20 mmol, yield 23.9%) of indolium iodide was obtained. The results of ¹ H-NMR are shown below.

¹ H-NMR (ppm, CDCl ₃ ): 9.15 (d, 1H), 8.70 (d, 1H), 8.32 (d, 1H), 8.15 (t, 1H), 7.92 (d, 1H), 7.83 (t, 1H), 7.80-7.70 ppm (m, 5H), 3.44 (s, 3H).

(c) 2-[[2-hydroxy-3-[(1-phenylbenz[cd]indol-2(1H)-ylidene)methyl]-4-oxo-2-cyclobuten-1-ylidene]methyl]-1 Synthesis of -phenyl-benz[cd]indolium (compound P1-1) 2-[[2-hydroxy-3-[(1-phenylbenz[cd]indole-2(1H)-ylidene) according to the scheme below Methyl]-4-oxo-2-cyclobuten-1-ylidene]methyl]-1-phenyl-benz[cd]indolium was synthesized.

A mixture of 6.8 mL of 1-butanol and 6.8 mL of toluene was heated to 107° C. under a nitrogen gas atmosphere. After dissolving 0.0613 g (0.537 mmol) of squaric acid in the resulting mixture, 0.399 g (11.07 mmol) of 2-methyl-1-phenyl-(1H)-benz[cd]indolium iodide was added. Further dissolution was achieved and the solution was heated to reflux for 2 hours.
After standing to cool, the solvent is distilled off under reduced pressure and recrystallized using ethanol to give 2-[[2-hydroxy-3-[(1-phenylbenz[cd]indole-2(1H )-ylidene)methyl]-4-oxo-2-cyclobuten-1-ylidene]methyl]-1-phenyl-benz[cd]indolium 0.215 g (0.381 mmol, yield 71.9%) was obtained. . The results of ¹ H-NMR are shown below.

¹ H-NMR (ppm, CDCl ₃ ): 9.24 (d, 2H), 7.98 (d, 2H), 7.86 (t, 2H), 7.68-7.46ppm (m, 12H) , 7.42 (t, 2H), 6.81 (d, 2H), 6.28 (s, 2H).

According to the method described in (II), the solution absorption spectrum of compound P1-1 and the film absorption spectrum of P1-1 were measured. The results are shown in FIG.

<Synthesis Example 2> Synthesis of compound P2-1 2-[[2-hydroxy-3-[(1-phenylbenz[cd]indole-2(1H)-ylidene)methyl]-4,5-dioxo-2-cyclopentene -1-ylidene]methyl]-1-phenyl-benz[cd]indolium (compound P2-1) was synthesized according to the following scheme.

A mixture of 7.4 mL of 1-butanol and 7.4 mL of toluene was heated to 107° C. under a nitrogen gas atmosphere. Next, after dissolving 0.0846 g (0.60 mmol) of croconic acid in the mixture, 0.442 g (1.19 mmol) of 2-methyl-1-phenyl-(1H)-benz[cd]indolium iodide was further added. The dissolved solution was heated to reflux for 3 hours.
After standing to cool, the solvent is distilled off under reduced pressure and recrystallized using ethanol to give 2-[[2-hydroxy-3-[(1-phenylbenz[cd]indole-2(1H )-ylidene)methyl]-4,5-dioxo-2-cyclopenten-1-ylidene]methyl]-1-phenyl-benz[cd]indolium 0.334 g (0.564 mmol, yield 94.8%) Obtained.

<Synthesis Example 3> Synthesis of Compound P3-1 Compound P3-1 was synthesized according to the following scheme.

A mixture of 48.5 mL of 1-butanol and 48.5 mL of toluene was heated to 107° C. under a nitrogen gas atmosphere. After dissolving 0.387 g (3.393 mmol) of croconic acid in the resulting mixture, ACS Appl. Mater. 2-methyl-1-octyl-(1H)-benz[cd]indolium iodide 2.764 g (6.786 mmol) synthesized with reference to the method described in Interfaces 2018, 10, 11063-11069 was further dissolved. The liquid was heated to reflux for 3 hours.
After standing to cool, the solvent was distilled off under reduced pressure, and the residue was recrystallized using ethanol to obtain 0.963 g of compound P3-1 (yield: 44.4%) as a dark brown solid.

<Comparative Synthesis Example 1> Synthesis of compound CP-1 ACS Appl. Mater. Compound CP-1 was synthesized according to the following scheme with reference to the method described in Interfaces 2018, 10, 11063-11069.

<Synthesis Example 5> Synthesis of compound P5-1 (a) Acta Cryst. 2004, E60, o2252±o2254, 4-(dimethylamino)pyridinium 2-butoxy-3-dicyanomethylene-4-oxocyclobut-1-en-1-olate was synthesized according to the above scheme.

At 23° C., malononitrile (7.03 g, 106.5 mmol) was dissolved in toluene to obtain a solution. 3,4-dibutoxy-3-cyclobutene-1,2-dione (24.56 g, 108.5 mmol) was added to the resulting solution to obtain a solution. 4-Dimethylaminopyridine (12.75 g, 104.4 mmol) was added to the resulting solution and stirred for 30 minutes to precipitate crystals. Crystals obtained by suction filtration were washed with toluene and diethyl ether to obtain 30.60 g of 4-(dimethylamino)pyridinium 2-butoxy-3-dicyanomethylene-4-oxocyclobut-1-en-1-oleate. Yield 86.1%.

(b) Synthesis of compound P5-1

Under a nitrogen atmosphere, 4-(dimethylamino)pyridinium 2-butoxy-3-dicyanomethylene-4-oxocyclobut-1-en-1-olate 40.9 mg (0.120 mmol), 2-methyl-1-octyl-(1H )-benz[cd]indolium iodide 97.8 mg (0.240 mmol) was dissolved to obtain a solution. The resulting solution was mixed with 1.7 mL of 1-butanol and 1.7 mL of toluene. The resulting mixture was heated to 107° C. and heated under reflux for 2 hours. After cooling, the solvent was distilled off under reduced pressure and the residue was recrystallized using ethanol to obtain 52.4 mg of compound P5-1 (yield: 63.7%) as a dark brown solid. The results of ¹ H-NMR and UV-vis absorption spectra are shown below.
¹ H-NMR (ppm, CDCl ₃ ): 8.77 (t, 2H), 8.02 (d, 2H), 7.84 (t, 2H), 7.64 (d, 2H), 7.55 (t, 2H), 7.16 (d, 2H), 6.82 (s, 2H), 4.21 (t, 4H), 1.93 (quintet, 4H), 1.49 (quintet, 4H) , 1.38 (quintet, 4H), 1.34-1.20 (m, 12H), 0.87 (t, 6H).

According to the method described in (II), the solution absorption spectrum of compound P5-1 and the film absorption spectrum of P5-1 were measured. The results are shown in FIG.

The compounds obtained in Synthesis Examples 1 and 5 exhibited strong absorption in the near-infrared region and relatively small absorption in the visible region.

<Example 1>
(Manufacturing of near-infrared photoelectric conversion element)
A near-infrared photoelectric conversion device is manufactured using the compound (p-type semiconductor material) P1-1 obtained in Synthesis Example 1 above. The near-infrared photoelectric conversion device produced in this example includes an anode, a hole transport layer (electron blocking layer), an active layer, an electron transport layer (hole blocking layer) and a cathode.

Specifically, among the glass substrates provided with an ITO layer, the ITO layer is patterned to prepare a glass substrate as an anode, which is then subjected to acetone ultrasonic cleaning and then UV ozone cleaning.
Next, using a solution containing polyethyleneimine, the solution is applied to the side where the anode is provided by a spin coating method, and the applied film is dried by heating to form a hole transport layer.

Next, on the hole transport layer, compound P1-1, which is the p-type semiconductor material obtained in Synthesis Example 1 above, and C60 fullerene, which is the n-type semiconductor material, are co-deposited by a vacuum heating vapor deposition method to form an active layer. to form

Next, molybdenum oxide (MoO ₃ ) is vapor-deposited on the active layer by a vacuum heating vapor deposition method to form an electron transport layer.

Then, Ag is vapor-deposited on the electron-transporting layer to form a cathode, thereby producing a near-infrared photoelectric conversion device.

After forming the cathode, the glass substrate having each of the above layers is transferred into a glove box without being exposed to the atmosphere, and a glass plate coated with a UV-curable epoxy resin is bonded together and irradiated with UV light for UV curing. The mold epoxy resin is cured to seal the near-infrared photoelectric conversion element.

(Evaluation of near-infrared photoelectric conversion element)
In order to evaluate the photoelectric conversion characteristics in the near-infrared light wavelength region, the spectral sensitivity of the near-infrared photoelectric conversion element is evaluated using a spectral sensitivity measurement device (CEP2000, manufactured by Spectro Keiki Co., Ltd.).

<Example 2>
(Manufacturing of near-infrared photoelectric conversion element)
A near-infrared photoelectric conversion device is manufactured using the compound P2-1, which is the p-type semiconductor material obtained in Synthesis Example 2 above. The near-infrared photoelectric conversion device of this example includes an anode, a hole transport layer, an active layer, an electron transport layer and a cathode.

Specifically, among the glass substrates provided with an ITO layer, the ITO layer is patterned to prepare a glass substrate as an anode, which is then subjected to acetone ultrasonic cleaning and then UV ozone cleaning.

Next, using a polyethyleneimine solution, the solution is applied to the side where the anode is provided by a spin coating method, and the applied film is dried by heating to form a hole transport layer.

Next, on the hole transport layer, the p-type semiconductor material compound P2-1 obtained in Synthesis Example 2 and the n-type semiconductor material C60PCBM were added at a weight ratio of 1:3 (p-type semiconductor material: n The active layer is formed by applying a solution in which the semiconductor material is dissolved in chloroform by spin coating to form a coating film, and drying the coating film by heating.

Next, molybdenum oxide (MoO ₃ ) is vapor-deposited on the active layer by a vacuum heating vapor deposition method to form an electron transport layer.

Then, Ag is vapor-deposited on the electron-transporting layer to form a cathode, thereby producing a near-infrared photoelectric conversion device.

After forming the cathode, the glass substrate having each of the above layers is transferred into a glove box without being exposed to the atmosphere, and a glass plate coated with a UV-curable epoxy resin is bonded together and irradiated with UV light for UV curing. The mold epoxy resin is cured to seal the near-infrared photoelectric conversion element.

(Evaluation of near-infrared photoelectric conversion element)
In order to evaluate the characteristics in the near-infrared light wavelength region, the spectral sensitivity of the near-infrared photoelectric conversion element is evaluated using a spectral sensitivity measurement device (CEP2000, manufactured by Spectroscopic Keiki Co., Ltd.).

<Example 3>
(Manufacturing and Evaluation of Near Infrared Photoelectric Conversion Device)
A near-infrared photoelectric conversion device is produced and evaluated in the same manner as in Example 1, except that compound P3-1 is used instead of compound P1-1.

<Example 4>
(Manufacturing and Evaluation of Near Infrared Photoelectric Conversion Device)
A near-infrared photoelectric conversion device is produced and evaluated in the same manner as in Example 2, except that compound P3-1 is used instead of compound P1-1.

<Example 5>
(Manufacturing and Evaluation of Near Infrared Photoelectric Conversion Device)
A near-infrared photoelectric conversion device is produced and evaluated in the same manner as in Example 1, except that compound P5-1 is used instead of compound P1-1.

<Example 6>
(Manufacturing and Evaluation of Near Infrared Photoelectric Conversion Device)
A near-infrared photoelectric conversion device is produced and evaluated in the same manner as in Example 2, except that compound P5-1 is used instead of compound P1-1.

<Comparative Example 1>
(Manufacturing and Evaluation of Near Infrared Photoelectric Conversion Device)
A near-infrared photoelectric conversion device is produced and evaluated in the same manner as in Example 1, except that compound CP-1 is used instead of compound P1-1.

<Comparative Example 2>
(Manufacturing and Evaluation of Near Infrared Photoelectric Conversion Device)
A near-infrared photoelectric conversion device is produced and evaluated in the same manner as in Example 2, except that compound CP-1 is used instead of compound P1-1.

The near-infrared photoelectric conversion elements of Examples 1 to 6 are excellent in photoelectric conversion efficiency in the near-infrared wavelength region and low in photoelectric conversion efficiency in the visible light region.

Claims (8)

A compound represented by the following formula (1), formula (2) or formula (3).

(In formula (1),
R ¹ and R ² each independently represent a hydrogen atom, an optionally substituted alkyl group, an optionally substituted halogenated alkyl group or a halogen atom. Multiple R ¹ 's may be the same or different, and multiple R ² 's may be the same or different. m represents an integer from 1 to 20; Multiple m may be the same or different.
Ar ¹ represents a diyl group of a polycyclic aromatic compound in which carbon atoms constituting the ring structure may be substituted with heteroatoms . Two Ar ¹ may be the same or different. C ¹ , C ² and C ³ represent carbon atoms constituting the diyl group of the polycyclic aromatic compound .
Ar ² represents a diyl group of a polycyclic aromatic compound in which carbon atoms constituting the ring structure may be substituted with heteroatoms .
Ar ¹ and Ar ² may combine with each other to form a ring. )

(In formula (2),
R ¹ , R ² , m and Ar ¹ have the same meanings as above. Multiple R ¹ 's may be the same or different, and multiple R ² 's may be the same or different. Multiple m may be the same or different.
A represents an optionally substituted alkylene group, an optionally substituted arylene group or an optionally substituted heteroarylene group. Two A's may be the same or different.
Ar ¹ and A may combine with each other to form a ring. )

(In formula (3),
R ¹ , R ² , m and Ar ¹ have the same meanings as above. Multiple R ¹ 's may be the same or different, and multiple R ² 's may be the same or different. Multiple m may be the same or different. Ar ¹ and A may combine with each other to form a ring. ) The compound according to claim 1, wherein two Ar ¹ -(R ² ) _m in formula (1) are the same, and two -Ar ² -R ¹ are the same, two in formula (2) The compound according to claim 1, wherein certain Ar ¹ -(R ² ) _m are the same and two -AR ¹ are the same, or two Ar ¹ -(R ² ) in formula (3) The compound according to claim 1, wherein _m are identical to each other and two --AR ¹ are identical to each other. A photoelectric conversion device comprising an anode, a cathode, and an active layer provided between the anode and the cathode, wherein the active layer comprises the compound according to claim 1 or 2. 4. The photoelectric conversion device according to claim 3, wherein said active layer comprises a p-type semiconductor material and an n-type semiconductor material, and said p-type semiconductor material is the compound according to claim 1 or 2. 5. The photoelectric conversion device according to claim 4, wherein said n-type semiconductor material is fullerene. 6. The photoelectric conversion device according to claim 5, wherein said n-type semiconductor material is C60 fullerene. 7. The photoelectric conversion device according to claim 3, which is a photodetector. An image sensor comprising the photoelectric conversion element according to claim 7 .

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