WO2024262486A1 - Photoelectric conversion element, imaging element, optical sensor, imaging element production method, and compound - Google Patents

Abstract

The present invention addresses the problem of providing a photoelectric conversion element that has excellent response speed when receiving green/red light and in which the dependence of the response speed on electric field intensity is small. A photoelectric conversion element according to the present invention has a conductive film, a photoelectric conversion film, and a transparent conductive film in this order. The photoelectric conversion film contains a compound represented by formula (1) or a compound represented by formula (2).

Description

Photoelectric conversion element, imaging element, optical sensor, imaging element manufacturing method, and compound

The present invention relates to a photoelectric conversion element, an imaging element, an optical sensor, a method for manufacturing an imaging element, and a compound.

In recent years, the development of elements having a photoelectric conversion film (for example, an image sensor) has progressed.
For example, Patent Document 1 and Non-Patent Document 1 disclose dye compounds with specific structures that can be used as dyes for dye-sensitized solar cells.

International Publication No. 2012/102544

Chemistry - An Asian Journal (2021), 16(24), 4171-4178

With the demand for improved performance of imaging elements and optical sensors, there is a demand for photoelectric conversion elements that exhibit excellent characteristics. For example, the characteristics required for photoelectric conversion elements include an excellent response speed when receiving green and red light. In addition, it is also required that the response speed of the photoelectric conversion element does not decrease easily even when the electric field strength is changed, that is, the response speed has a small electric field strength dependency.
In response to such demands, the present inventors have produced and investigated a photoelectric conversion element containing the compound disclosed in Patent Document 1, and have found that there is a need to improve the response speed when green and red light is received and the dependency of the response speed on the electric field strength. In this specification, the green and red light means light having a wavelength of 500 to 650 nm.

Therefore, an object of the present invention is to provide a photoelectric conversion element which has an excellent response speed when receiving green and red light and has a small dependency of the response speed on the electric field strength.
Another object of the present invention is to provide an imaging element, an optical sensor, a method for manufacturing an imaging element, and a compound related to the above-mentioned photoelectric conversion element.

　As a result of extensive research into solving the above problems, the inventors have discovered that the problems can be solved by the following configuration.

[1] A photoelectric conversion element having a conductive film, a photoelectric conversion film, and a transparent conductive film in this order, wherein the photoelectric conversion film contains a compound represented by formula (1) described later or a compound represented by formula (2) described later.
[2] The photoelectric conversion element according to [1], wherein in the formula (1), ^X2 represents an oxygen atom or a sulfur atom.
[3] The photoelectric conversion element according to [1] or [2], wherein in the formula (2), X ⁴ represents a sulfur atom.
[4] In the above formula (1), X ¹ represents -C(R ^c1 R ^c2 )-;
The photoelectric conversion element according to any one of [1] to [3], wherein in the above formula (2), X ³ represents —C(R ^c11 R ^c12 )—.
R ^c1 and R ^c2 do not bond to each other to form a ring which may have a substituent, and R ^c11 and R ^c12 do not bond to each other to form a ring which may have a substituent.
[5] In the above formula (1), R ^c1 and R ^c2 are different groups, R ^c3 and R ^c4 are different groups, R ^c5 and R ^c6 are different groups, and R ^c7 and R ^c8 are different groups;
In the above formula (2), R ^c11 and R ^c12 are different groups, R ^c13 and R ^c14 are different groups, R ^c15 and R ^c16 are different groups, and R ^c17 and R ^c18 are different groups. The photoelectric conversion element according to any one of [1] to [4].
[6] The photoelectric conversion element according to any one of [1] to [5], wherein the group represented by the formula (A-1) is a group represented by the formula (A-2) described below.
[7] The photoelectric conversion element according to [6], wherein the group represented by the formula (A-2) is a group represented by the formula (C-1) or the formula (C-2) described later.
[8] In the above formula (C-1), ^Xc1 and ^Xc2 represent oxygen atoms;
The photoelectric conversion element according to [7], wherein in the formula (C-2), X ^c3 and X ^c4 each represent an oxygen atom.
[9] The photoelectric conversion film further contains an n-type organic semiconductor,
The photoelectric conversion element according to any one of [1] to [8], wherein the photoelectric conversion film has a bulk heterostructure formed in a state in which the compound represented by the formula (1) and the n-type organic semiconductor are mixed.
[10] The photoelectric conversion element according to [9], wherein the n-type organic semiconductor contains a fullerene selected from the group consisting of fullerenes and derivatives thereof.
[11] The photoelectric conversion element according to any one of [1] to [10], wherein the photoelectric conversion film further contains a p-type organic semiconductor.
[12] The photoelectric conversion element according to any one of [1] to [11], wherein the photoelectric conversion film further contains a dye.
[13] The photoelectric conversion element according to any one of [1] to [12], further comprising one or more intermediate layers between the conductive film and the transparent conductive film in addition to the photoelectric conversion film.
[14] An imaging element having the photoelectric conversion element according to any one of [1] to [13].
[15] An optical sensor comprising the photoelectric conversion element according to any one of [1] to [13].
[16] A method for producing an imaging element, comprising the step of producing the photoelectric conversion element according to any one of [1] to [13].
[17] A compound represented by the following formula (1) or the following formula (2).
[18] The compound according to [17], wherein in the above formula (1), ^X2 represents an oxygen atom or a sulfur atom.
[19] The compound according to [17] or [18], wherein in the above formula (2), X ⁴ represents a sulfur atom.
[20] In the above formula (1), X ¹ represents -C(R ^c1 R ^c2 )-;
The compound according to any one of [17] to [19], wherein, in the above formula (2), X ³ represents —C(R ^c11 R ^c12 )—.
R ^c1 and R ^c2 do not bond to each other to form a ring which may have a substituent, and R ^c11 and R ^c12 do not bond to each other to form a ring which may have a substituent.
[21] In the above formula (1), R ^c1 and R ^c2 are different groups, R ^c3 and R ^c4 are different groups, R ^c5 and R ^c6 are different groups, and R ^c7 and R ^c8 are different groups;
In the above formula (2), R ^c11 and R ^c12 are different groups, R ^c13 and R ^c14 are different groups, R ^c15 and R ^c16 are different groups, and R ^c17 and R ^c18 are different groups. The compound according to any one of [17] to [20].
[22] The compound according to any one of [17] to [21], wherein the group represented by formula (A-1) is a group represented by formula (A-2) described below.
[23] The compound according to [22], wherein the group represented by the formula (A-2) is a group represented by the formula (C-1) or the formula (C-2) described later.
[24] In the above formula (C-1), ^Xc1 and ^Xc2 represent oxygen atoms;
The compound according to [23], wherein in the formula (C-2), X ^c3 and X ^c4 represent an oxygen atom.

According to the present invention, it is possible to provide a photoelectric conversion element which has an excellent response speed when receiving green and red light and in which the response speed has a small dependency on the electric field strength.
Furthermore, according to the present invention, there can be provided an imaging element, an optical sensor, a method for manufacturing an imaging element, and a compound related to the above-mentioned photoelectric conversion element.

FIG. 2 is a schematic cross-sectional view showing a configuration example of a photoelectric conversion element. FIG. 2 is a schematic cross-sectional view showing a configuration example of a photoelectric conversion element.

The present invention will be described in detail below.
The following description of the components may be based on a representative embodiment of the present invention, but the present invention is not limited to such an embodiment.

In this specification, a numerical range expressed using "~" means a range that includes the numerical values written before and after "~" as the lower and upper limits.

In this specification, the hydrogen atom may be either a protium atom (normal hydrogen atom) or a deuterium atom (for example, a deuterium atom, etc.).
In this specification, when there are a plurality of substituents, linking groups, etc. (hereinafter also referred to as "substituents, etc.") represented by specific symbols, or when a plurality of substituents, etc. are simultaneously specified, it means that the respective substituents, etc. may be the same or different from each other. This also applies to the specification of the number of substituents, etc.

In this specification, unless otherwise specified, the "substituent" includes the groups exemplified by the substituent W below.

(Substituent W)
The substituent W in this specification will be described.
Examples of the substituent W include a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc.), an alkyl group (including a cycloalkyl group, a bicycloalkyl group, and a tricycloalkyl group), an alkenyl group (including a cycloalkenyl group and a bicycloalkenyl group), an alkynyl group, an aryl group, a heterocyclic group (a heteroaryl group, or an aliphatic heterocyclic group), a cyano group, a nitro group, an alkoxy group, an aryloxy group, a silyl group, a silyloxy group, a heterocyclic oxy group, an acyloxy group, a carbamoyloxy group, an alkoxycarbonyloxy group, an aryloxycarbo Examples of the substituent W include nyloxy group, primary, secondary or tertiary amino group (including anilino group), alkylthio group, arylthio group, heterocyclic thio group, alkyl or arylsulfinyl group, alkyl or arylsulfonyl group, acyl group, aryloxycarbonyl group, alkoxycarbonyl group, aryl or heterocyclic azo group, imido group, phosphino group, phosphinyl group, phosphinyloxy group, phosphinylamino group, phosphono group, carboxy group, phosphoric acid group, sulfonic acid group, hydroxy group, thiol group, acylamino group, carbamoyl group, ureido group, and boronic acid group. In addition, each of the above groups may further have a substituent (e.g., one or more groups among the above groups, etc.) if possible. For example, an alkyl group that may have a substituent is also included as one form of the substituent W.
When the substituent W has a carbon atom, the number of carbon atoms contained in the substituent W is, for example, 1 to 20.
The number of atoms other than hydrogen atoms contained in the substituent W is, for example, 1 to 30.
In addition, it is also preferable that the specific compound described later does not have a carboxy group, a salt of a carboxy group, a salt of a phosphate group, a sulfonic acid group, a salt of a sulfonic acid group, a hydroxy group, a thiol group, an acylamino group, a carbamoyl group, a ureido group, a boronic acid group (-B(OH) ₂ ), and/or a primary amino group as a substituent.

In this specification, examples of halogen atoms include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms.

In this specification, the aliphatic hydrocarbon group may be any of linear, branched, and cyclic.
Examples of the aliphatic hydrocarbon group include an alkyl group, an alkenyl group, and an alkynyl group.
In this specification, unless otherwise specified, the alkyl group preferably has 1 to 20 carbon atoms, more preferably 1 to 10 carbon atoms, and even more preferably 1 to 6 carbon atoms.
The alkyl group may be linear, branched, or cyclic.
Examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, an n-hexyl group, a cyclopropyl group, and a cyclopentyl group.
The alkyl group may be any one of a cycloalkyl group, a bicycloalkyl group, and a tricycloalkyl group, and may have these ring structures as partial structures.
In the alkyl group which may have a substituent, examples of the substituent which the alkyl group may have include the groups exemplified by the substituent W. Among them, an aryl group (preferably having 6 to 18 carbon atoms, more preferably having 6 carbon atoms), a heteroaryl group (preferably having 5 to 18 carbon atoms, more preferably having 5 to 6 carbon atoms) or a halogen atom (preferably a fluorine atom or a chlorine atom) is preferred.

In this specification, unless otherwise specified, the alkyl group moiety in the alkoxy group is preferably the above-mentioned alkyl group, and the alkyl group moiety in the alkylthio group is preferably the above-mentioned alkyl group.
In the alkoxy group which may have a substituent, examples of the substituent which the alkoxy group may have include the same substituents as those in the alkyl group which may have a substituent.
In the alkylthio group which may have a substituent, examples of the substituent which the alkylthio group may have include the same substituents as those in the alkyl group which may have a substituent.

In this specification, unless otherwise specified, the alkenyl group may be any of linear, branched, and cyclic. The number of carbon atoms in the alkenyl group is preferably 2 to 20. In the alkenyl group which may have a substituent, examples of the substituent which the alkenyl group may have include the same as those of the substituent in the alkyl group which may have a substituent.
In this specification, unless otherwise specified, the alkynyl group may be any of linear, branched, and cyclic. The number of carbon atoms in the alkynyl group is preferably 2 to 20. In the alkynyl group which may have a substituent, examples of the substituent which the alkynyl group may have include the same as those of the substituent in the alkyl group which may have a substituent.

In this specification, unless otherwise specified, an aromatic ring or an aromatic ring constituting an aromatic ring group may be either a monocyclic ring or a polycyclic ring (e.g., 2 to 6 rings). A monocyclic aromatic ring is an aromatic ring having only one aromatic ring structure as a ring structure. A polycyclic (e.g., 2 to 6 rings) aromatic ring is an aromatic ring having a plurality of (e.g., 2 to 6 rings) aromatic ring structures condensed as ring structures.
The aromatic ring preferably has 5 to 15 ring atoms.
The aromatic ring may be an aromatic hydrocarbon ring or an aromatic heterocycle.
When the aromatic ring is an aromatic heterocycle, the number of heteroatoms contained as ring member atoms is, for example, 1 to 10. Examples of the heteroatom include a nitrogen atom, a sulfur atom, an oxygen atom, a selenium atom, a tellurium atom, a phosphorus atom, a silicon atom, and a boron atom.
Examples of the aromatic hydrocarbon ring include a benzene ring, a naphthalene ring, an anthracene ring, a pyrene ring, a phenanthrene ring, and a fluorene ring.
Examples of the aromatic heterocycle include a pyridine ring, a pyrimidine ring, a pyridazine ring, a pyrazine ring, a triazine ring (e.g., a 1,2,3-triazine ring, a 1,2,4-triazine ring, and a 1,3,5-triazine ring), a tetrazine ring (e.g., a 1,2,4,5-tetrazine ring), a quinoxaline ring, a pyrrole ring, a furan ring, a thiophene ring, an imidazole ring, an oxazole ring, a thiazole ring, a benzopyrrole ring, a benzofuran ring, a benzothiophene ring, a benzimidazole ring, a benzoxazole ring, a benzothiazole ring, a naphthopyrrole ring, a naphthofuran ring, a naphthothiophene ring, a naphthoimidazole ring, a naphthoxazole ring, a pyrroloimidazole ring (e.g., a 5H-pyrrolo[1,2-a]imidazole ring), and an imidazooxazole ring (e.g., an imidazo[2,1-b]oxazole ring). , thienothiazole ring (for example, thieno[2,3-d]thiazole ring, etc.), benzothiadiazole ring, benzodithiophene ring (for example, benzo[1,2-b:4,5-b']dithiophene ring, etc.), thienothiophene ring (for example, thieno[3,2-b]thiophene ring, etc.), thiazolothiazole ring (for example, thiazolo[5,4-d]thiazole ring, etc.), naphthodithiophene ring (for example, naphtho[2,3 [2,1-b:6,7-b']dithiophene ring, naphtho[2,1-b:6,5-b']dithiophene ring, naphtho[1,2-b:5,6-b']dithiophene ring, 1,8-dithiadicyclopenta[b,g]naphthalene ring, etc.), benzothienobenzothiophene ring, dithieno[3,2-b:2',3'-d]thiophene ring, and 3,4,7,8-tetrathiadicyclopenta[a,e]pentalene ring.

In this specification, the term "aromatic ring group" includes, for example, groups obtained by removing one or more (eg, 1 to 5, etc.) hydrogen atoms from the above-mentioned aromatic ring.
In this specification, the term "aryl group" includes, for example, a group in which one hydrogen atom has been removed from a ring that corresponds to an aromatic hydrocarbon ring among the above aromatic rings.
In this specification, the term "heteroaryl group" includes, for example, a group in which one hydrogen atom has been removed from a ring corresponding to an aromatic heterocycle among the above aromatic rings.
In this specification, the term "arylene group" includes, for example, a group formed by removing two hydrogen atoms from a ring corresponding to an aromatic hydrocarbon ring among the above aromatic rings.
In this specification, the term "heteroarylene group" includes, for example, a group formed by removing two hydrogen atoms from a ring corresponding to an aromatic heterocycle among the above aromatic rings.
In the aromatic ring group which may have a substituent, the aryl group which may have a substituent, the heteroaryl group which may have a substituent, the arylene group which may have a substituent, and the heteroarylene group which may have a substituent, the types of the substituents which these groups may have include, for example, the groups exemplified for the substituent W. When these groups which may have a substituent have a substituent, the number of the substituents may be 1 or more (for example, 1 to 4, etc.).

In this specification, the term "non-aromatic ring" refers to a ring structure that is not aromatic, and examples thereof include an aliphatic hydrocarbon ring and an aliphatic heterocycle.
Examples of the aliphatic hydrocarbon ring include cycloalkanes, cycloalkenes, and cycloalkynes.
The number of heteroatoms contained as ring member atoms in the aliphatic heterocycle is, for example, 1 to 10. Examples of the heteroatom include a nitrogen atom, a sulfur atom, an oxygen atom, a selenium atom, a tellurium atom, a phosphorus atom, a silicon atom and a boron atom.
Examples of the aliphatic heterocycle include a pyrrolidine ring, an oxolane ring, a thiolane ring, a piperidine ring, a tetrahydropyran ring, a thiane ring, a piperazine ring, a morpholine ring, a quinuclidine ring, an azetidine ring, an oxetane ring, an aziridine ring, a dioxane ring, and γ-butyrolactone.
In this specification, the term "aliphatic hydrocarbon ring group" includes, for example, a group obtained by removing one hydrogen atom from a ring corresponding to an aliphatic hydrocarbon ring.
In this specification, the term "aliphatic heterocyclic group" includes, for example, a group obtained by removing one hydrogen atom from a ring corresponding to an aliphatic heterocycle.

In this specification, when a formula showing a chemical structure contains a plurality of identical symbols showing the type or number of groups, unless otherwise specified, the contents of the plurality of identical symbols are independent of each other, and the contents of the plurality of identical symbols may be the same or different.
In this specification, when a formula showing a chemical structure contains a plurality of groups of the same type (for example, alkyl groups, etc.), the specific contents of the plurality of groups of the same type are independent of each other, unless otherwise specified, and the specific contents of the groups of the same type may be the same or different.

In this specification, the bond direction of the divalent group (e.g., -CO-O-, etc.) is not limited unless otherwise specified. For example, if Y is -CO-O- in a compound represented by the formula "X-Y-Z", the compound may be either "X-O-CO-Z" or "X-CO-O-Z".

In this specification, for compounds that may have geometric isomers (cis-trans isomers), the general formula or structural formula representing the compound may be described in only one of the cis and trans forms for convenience. Even in such cases, unless otherwise specified, the form of the compound is not limited to either the cis or trans form, and the compound may be in either the cis or trans form.

In this specification, unless otherwise specified, the * in the formula indicates the bond position.

[Photoelectric conversion element]
The photoelectric conversion element of the present invention is a photoelectric conversion element having a conductive film, a photoelectric conversion film, and a transparent conductive film in this order, and the photoelectric conversion film contains a compound represented by formula (1) or a compound represented by formula (2) (hereinafter also referred to as a "specific compound").

Although the reason why the photoelectric conversion element having the above configuration can solve the problems of the present invention is not necessarily clear, the present inventors speculate as follows.
The mechanism by which the effects are obtained is not limited by the following speculation. In other words, even if the effects are obtained by a mechanism other than the following, it is included in the scope of the present invention.
The specific compound is a so-called ADA type dye compound having a donor portion (D) and an acceptor portion (A). The ADA type dye compound tends to have high aggregation due to its conjugated structure and polar structure. The specific compound has a specific condensed ring structure containing a specific atom as represented by formula (1) and formula (2), thereby suppressing excessive aggregation between the specific compounds in the photoelectric conversion film, and efficient charge separation can be achieved. As a result, the photoelectric conversion element containing the specific compound is considered to have excellent response speed and small electric field strength dependency of the response speed.
Hereinafter, achieving at least one of a better response speed and a smaller dependency of the response speed on the electric field strength is also referred to as "the effect of the present invention being better."

FIG. 1 is a schematic cross-sectional view of one embodiment of a photoelectric conversion element of the present invention.
The photoelectric conversion element 10a shown in Figure 1 has a configuration in which a conductive film (hereinafter also referred to as the "lower electrode") 11 functioning as a lower electrode, an electron blocking film 16A, a photoelectric conversion film 12 containing a specific compound, and a transparent conductive film (hereinafter also referred to as the "upper electrode") 15 functioning as an upper electrode are stacked in this order.
Fig. 2 shows a configuration example of another photoelectric conversion element. The photoelectric conversion element 10b shown in Fig. 2 has a configuration in which an electron blocking film 16A, a photoelectric conversion film 12, a hole blocking film 16B, and an upper electrode 15 are laminated in this order on a lower electrode 11. The laminated order of the electron blocking film 16A, the photoelectric conversion film 12, and the hole blocking film 16B in Figs. 1 and 2 may be changed as appropriate depending on the application and characteristics.

In the photoelectric conversion element 10 a (or 10 b ), it is preferable that light is incident on the photoelectric conversion film 12 through the upper electrode 15 .
Furthermore, when the photoelectric conversion element 10a (or 10b) is used, a voltage can be applied. In this case, the lower electrode 11 and the upper electrode 15 form a pair of electrodes, and it is preferable to apply a voltage of 1×10 ⁻⁵ to 1×10 ⁷ V/cm between the pair of electrodes. In terms of performance and power consumption, the applied voltage is more preferably 1×10 ⁻⁴ to 1×10 ⁷ V/cm, and even more preferably 1×10 ⁻³ to 5×10 ⁶ V/cm.
1 and 2, the voltage is preferably applied so that the electron blocking film 16A side becomes the cathode and the photoelectric conversion film 12 side becomes the anode. When the photoelectric conversion element 10a (or 10b) is used as an optical sensor or incorporated in an imaging element, a voltage can be applied in a similar manner.
As will be described in detail later, the photoelectric conversion element 10a (or 10b) can be suitably used as an imaging element.
The configuration of each layer constituting the photoelectric conversion element of the present invention will be described in detail below.

[Photoelectric conversion film]
The photoelectric conversion element has a photoelectric conversion film.

<Specific Compounds>
The photoelectric conversion film contains a specific compound which is a compound represented by formula (1) or formula (2).
The specific compound is preferably a compound represented by formula (1) in that the effect of the present invention is more excellent.

In formula (1), R ¹ and R ² each independently represent a hydrogen atom or a substituent.
^X1 represents -C( ^{Rc1Rc2 )} -, -O-C( ^Rc3Rc4 )-, -Si( ^Rc5Rc6 )-, or -Ge( ^Rc7Rc8 )-. Rc1, ^Rc2 , ^Rc3 , ^Rc4 , ^Rc5 , ^Rc6 , ^Rc7 , and ^Rc8 each independently represent a hydrogen atom or a substituent. ^Rc1 and ^Rc2 , ^{Rc3 and Rc4} , ^Rc5 and ^Rc6 , and ^{Rc7 and Rc8 may each} be bonded to each other to form a ring which may have ^a substituent.
^X2 represents an oxygen atom, a sulfur atom, or -NR ^N1 -, where R ^N1 represents a hydrogen atom or a substituent.
^A1 and ^A2 each independently represent a group represented by formula (A-1).
In formula (2), ^R3 and ^R4 each independently represent a hydrogen atom or a substituent.
R ^N2 represents a hydrogen atom or a substituent.
^X3 represents -C( ^{Rc11Rc12 )} -, -O-C( ^Rc13Rc14 )-, -Si( ^Rc15Rc16 )-, or -Ge( ^Rc17Rc18 )-. ^Rc11 , ^Rc12 , ^Rc13 , ^Rc14 , ^Rc15 , ^Rc16 , ^Rc17 , and ^Rc18 each independently represent a hydrogen atom or a substituent. ^Rc11 and ^Rc12 , ^{Rc13 and Rc14 , Rc15 and Rc16, and Rc17 and Rc18 may each be bonded} to each other to form a ring which may have ^a substituent.
^X4 represents a sulfur atom or -NR ^N3 -, where R ^N3 represents a hydrogen atom or a substituent.
^A3 and ^A4 each independently represent a group represented by formula (A-1).
In formula (A-1), * represents a bonding position.
^C1 represents a ring containing 2 or more carbon atoms which may have a substituent.
^W1 represents an oxygen atom, a sulfur atom, =NR ^W2 or =CR ^W3 R ^W4 .
R ^W2 represents a hydrogen atom or a substituent. R ^W3 and R ^W4 each independently represent a cyano group, -SO ₂ R ^W5 , -COOR ^W6 or -COR ^W7 . R ^W5 to R ^W7 each independently represent an aliphatic hydrocarbon group which may have a substituent, an aromatic ring group which may have a substituent, or an aliphatic heterocyclic group which may have a substituent.

In formula (1), R ¹ and R ² each independently represent a hydrogen atom or a substituent.
Examples of the substituent include the substituents exemplified for the substituent W described above.
In terms of obtaining superior effects of the present invention, R ¹ and R ² are preferably hydrogen atoms.

In formula (1), ^X1 represents -C( ^Rc1Rc2 )-, -O ^- C ^{(Rc3Rc4 )} - ^{, -Si} ( ^Rc5Rc6 )-, or -Ge( ^Rc7Rc8 )-.
In terms of superior effects of the present invention, X ¹ is preferably —C(R ^c1 R ^c2 )— or —Si(R ^c5 R ^c6 )—, and more preferably —C(R ^c1 R ^c2 )—.

R ^c1 , R ^c2 , R ^c3 , R ^c4 , R ^c5 , R ^c6 , R ^c7 , and R ^c8 each independently represent a hydrogen atom or a substituent.
Examples of the substituent include the substituents exemplified for the substituent W described above.
More specific examples of the substituent include an alkyl group which may have a substituent, an alkenyl group which may have a substituent, an alkynyl group which may have a substituent, an aryl group which may have a substituent, a heteroaryl group which may have a substituent, an alkoxy group which may have a substituent, an aryloxy group which may have a substituent, an amino group which may have a substituent, an aliphatic heterocyclic group which may have a substituent, an acyl group which may have a substituent, a silyl group, a cyano group, or a halogen atom.
The above-mentioned substituent is also preferably a substituent represented by Rs described below.

The substituents that may be possessed by each of the above groups that may have a substituent include the substituents exemplified as the substituent W described above, and the substituents selected from the substituent group S described below are preferred.

The alkyl group may be linear, branched, or cyclic.
The cyclic alkyl group may be either a monocyclic or polycyclic group, i.e., a cycloalkyl group, a bicycloalkyl group, a tricycloalkyl group, or the like.
The alkyl group preferably has 1 to 20 carbon atoms, more preferably 1 to 10 carbon atoms, and even more preferably 1 to 5 carbon atoms.
Among these, the linear alkyl group preferably has 1 to 5 carbon atoms, more preferably 1 to 4 carbon atoms, and even more preferably 1 or 2 carbon atoms.
The branched alkyl group preferably has 3 to 5 carbon atoms, more preferably 3 to 4 carbon atoms, and even more preferably 3 carbon atoms.
The cyclic alkyl group preferably has 3 to 6 carbon atoms, and more preferably has 3 to 5 carbon atoms.

The alkenyl group and alkynyl group may be straight-chain, branched-chain, or cyclic.
The cyclic alkenyl and alkynyl groups may be either monocyclic or polycyclic, for example, a cycloalkenyl group or a bicycloalkenyl group.
The alkenyl group and alkynyl group preferably have 2 to 21 carbon atoms, more preferably 2 to 11 carbon atoms, further preferably 2 to 6 carbon atoms, and particularly preferably 2 to 5 carbon atoms.

The aryl group and heteroaryl group may be either a monocyclic or polycyclic group, and is preferably a monocyclic group.
The aryl group preferably has 5 to 18 carbon atoms, more preferably 6 to 10 carbon atoms, and even more preferably 6 to 8 carbon atoms.
The definition and specific examples of the aryl group are as described above, and a phenyl group or naphthyl group is preferable, and a phenyl group is more preferable.
The heteroaryl group preferably has 5 to 18 ring atoms, more preferably 5 to 10 ring atoms, and even more preferably 5 to 8 ring atoms.
Examples of the heteroatom contained in the heteroaryl group include a sulfur atom, an oxygen atom, a nitrogen atom, a selenium atom, a tellurium atom, a phosphorus atom, a silicon atom, and a boron atom, and a sulfur atom, an oxygen atom, or a nitrogen atom is preferable.
The definition and specific examples of the heteroaryl group are as described above, and a thiophene ring group, a furan ring group, or a pyridine ring group is preferable.
The aryl and heteroaryl groups may have a substituent as described above. When the aryl and heteroaryl groups have a substituent, the number of the substituents is not particularly limited, but is preferably 1 to 3.

Preferred embodiments of the alkyl group in the alkoxy group are the same as the alkyl groups exemplified as the substituents represented by R ^c1 , ^{R c2} , R ^c3 , R c4 , R ^c5 , R ^c6 , R ^c7 , and R ^c8 .
The alkoxy group preferably has 1 to 20 carbon atoms, more preferably 1 to 10 carbon atoms, further preferably 1 to 5 carbon atoms, and particularly preferably 1 to 3 carbon atoms.
Examples of the alkoxy group include a methoxy group, an ethoxy group, an n-propoxy group, an n-butoxy group, a t-butoxy group, and a cyclopropoxy group.

The aryl group contained in the aryloxy group may be either a monocyclic or polycyclic ring.
The aryloxy group preferably has 5 to 18 carbon atoms, more preferably 6 to 10 carbon atoms, and even more preferably 6 to 8 carbon atoms.
The aryloxy group includes, for example, a phenoxy group.

The amino group may be any of a primary amino group, a secondary amino group, and a tertiary amino group.
In the above secondary amino group and tertiary amino group, the substituent on the nitrogen atom is preferably a hydrocarbon group, more preferably an alkyl group (preferably having 1 to 5 carbon atoms) or an aryl group.

The aliphatic heterocyclic group may be either a monocyclic or polycyclic group, and is preferably a monocyclic group.
The aliphatic heterocyclic group preferably has 3 to 18 ring atoms, more preferably 5 to 10 ring atoms, and even more preferably 5 to 8 ring atoms.
Examples of the heteroatom of the aliphatic heterocyclic group include a sulfur atom, an oxygen atom, a nitrogen atom, a selenium atom, a tellurium atom, a phosphorus atom, a silicon atom, and a boron atom, and a sulfur atom, an oxygen atom, or a nitrogen atom is preferable.
Specific examples of the aliphatic heterocyclic group are as described above, and a thiolane ring group, a piperidine ring group, a tetrahydrofuran ring group, or a tetrahydropyran ring group is preferred.
The aliphatic heterocyclic group may have a substituent as described above. When the aliphatic heterocyclic group has a substituent, the number of the substituents is not particularly limited, but is preferably 1 to 3.

The hydrocarbon group contained in the acyl group may be any one of an alkyl group, an alkenyl group, an alkynyl group, and an aryl group, preferably an alkyl group or an aryl group, and more preferably an alkyl group.
The acyl group preferably has 1 to 20 carbon atoms, more preferably 1 to 10 carbon atoms, further preferably 1 to 6 carbon atoms, and particularly preferably 1 or 2 carbon atoms.
Examples of the acyl group include a formyl group, an acetyl group, a propionyl group, a butyryl group, an isobutyryl group, a pivaloyl group, a hexanoyl group, and a benzoyl group, with the acetyl group being preferred.

The silyl group is a group represented by -Si(R ^Si ) _3. Each R ^Si independently represents an alkyl group, an alkenyl group, an alkynyl group, or an aryl group.
The definitions and preferred embodiments of the alkyl group, alkenyl group, alkynyl group, and aryl group represented by R ^Si are the same as those of the alkyl group, alkenyl ^group , alkynyl group, and aryl group exemplified as the substituents represented by R ^c1 , R ^c2 , R ^c3 , R c4, R ^c5 , R ^c6 , R ^c7 , and R ^c8 .

The above halogen atoms include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms, with fluorine atoms and chlorine atoms being preferred.

R ^c1 and R ^c2 , R ^c3 and R ^c4 , R ^c5 and R ^c6 , and R ^c7 and R ^c8 may be bonded to each other to form a ring which may have a substituent. However, in terms of the effects of the present invention being more excellent, it is also preferable that they do not form a ring.
The ring may be either an aromatic ring or a non-aromatic ring, and may be either a monocyclic ring or a polycyclic ring.
The ring may have a heteroatom, such as a nitrogen atom, a sulfur atom, an oxygen atom, a selenium atom, a tellurium atom, a phosphorus atom, a silicon atom, or a boron atom, and is preferably a sulfur atom, a nitrogen atom, or an oxygen atom.
The ring preferably has 3 to 20 member atoms, more preferably 5 to 12 member atoms, and even more preferably 5 to 8 member atoms.
Examples of the substituent that the ring may have include the substituents exemplified for the substituent W described above, and a substituent selected from the substituent group S described below is preferred.

In terms of the superiority of the present invention, it is also preferable that R ^c1 and R ^c2 are different groups, R ^c3 and R ^c4 are different groups, R ^c5 and R ^c6 are different groups, and R ^c7 and R ^c8 are different groups.

In formula (1), X ² represents an oxygen atom, a sulfur atom, or —NR ^N1 —.
In terms of obtaining superior effects of the present invention, ^X2 is preferably an oxygen atom or a sulfur atom.

R ^N1 represents a hydrogen atom or a substituent.
Examples of the substituent include the substituents exemplified for the substituent W described above.
More specifically, examples of the substituent include an alkyl group which may have a substituent, an alkenyl group which may have a substituent, an alkynyl group which may have a substituent, an aryl group which may have a substituent, and a heteroaryl group which may have a substituent.
R ^N1 is also preferably a substituent represented by Rt described below.

The definitions and preferred embodiments of each substituent represented by R ^N1 are the same as those of each group exemplified as the substituents represented by R ^c1 , R ^c2 , R ^c3 , R ^{c4 , R c5 ,} R ^c6 , R ^c7 , and R ^c8 described above.

In formula (1), A ¹ and A ² each independently represent a group represented by formula (A-1).
Formula (A-1) will be described later.

In formula (2), ^R3 and ^R4 each independently represent a hydrogen atom or a substituent.
Examples of the substituent include the substituents exemplified for the substituent W described above.
In terms of obtaining superior effects of the present invention, ^R3 and ^R4 are preferably hydrogen atoms.

In formula (2), R ^N2 represents a hydrogen atom or a substituent.
Examples of the substituent include the substituents exemplified for the substituent W described above.
More specifically, examples of the substituent include an alkyl group which may have a substituent, an alkenyl group which may have a substituent, an alkynyl group which may have a substituent, an aryl group which may have a substituent, and a heteroaryl group which may have a substituent.
R ^N2 is also preferably a group represented by Rt described below.
The definition and preferred embodiments of the group represented by R ^N2 are the same as those of the group represented by R ^N1 in formula (1).

In formula (2), ^{X3 represents -C(Rc11Rc12 )} -, -O ^- C ^{( Rc13Rc14} )-, -Si( ^Rc15Rc16 )-, or -Ge( ^Rc17Rc18 )-.
In terms of superior effects of the present invention, X ³ is preferably —C(R ^c11 R ^c12 )— or —Si(R ^c15 R ^c16 )—, and more preferably —C(R ^c11 R ^c12 )—.

^Rc11 , ^Rc12 , ^Rc13 , ^Rc14 , ^Rc15 , ^Rc16 , ^Rc17 , and ^Rc18 each independently represent a hydrogen atom or a substituent.
Examples of the substituent include the substituents exemplified for the substituent W described above.
More specific examples of the substituent include an alkyl group which may have a substituent, an alkenyl group which may have a substituent, an alkynyl group which may have a substituent, an aryl group which may have a substituent, a heteroaryl group which may have a substituent, an alkoxy group which may have a substituent, an aryloxy group which may have a substituent, an amino group which may have a substituent, an aliphatic heterocyclic group which may have a substituent, an acyl group which may have a substituent, a silyl group, a cyano group, or a halogen atom.
The above-mentioned substituent is also preferably a substituent represented by Rs described below.
The definitions and preferred embodiments of the groups represented by Rc11, ^Rc12 , Rc13, ^Rc14 , ^{Rc15 , Rc16} , Rc17, and ^Rc18 are the same as those of the groups represented by ^Rc1 , ^Rc2 , ^Rc3 , ^Rc4 , ^Rc5 , ^Rc6 , ^Rc7 , and ^Rc8 in formula ( ¹ ) ^.

R ^c11 and R ^c12 , R ^c13 and R ^c14 , R ^c15 and R ^c16 , and R ^c17 and R ^c18 may be bonded to each other to form a ring which may have a substituent, but in terms of the effects of the present invention being more excellent, it is also preferable that they do not form a ring.
The ring may be either an aromatic ring or a non-aromatic ring, and may be either a monocyclic ring or a polycyclic ring.
The ring may have a heteroatom, such as a nitrogen atom, a sulfur atom, an oxygen atom, a selenium atom, a tellurium atom, a phosphorus atom, a silicon atom, or a boron atom, and is preferably a sulfur atom, a nitrogen atom, or an oxygen atom.
The ring preferably has 3 to 20 member atoms, more preferably 5 to 12 member atoms, and even more preferably 5 to 8 member atoms.
Examples of the substituent that the ring may have include the substituents exemplified for the substituent W described above, and a substituent selected from the substituent group S described below is preferred.

In terms of the superiority of the present invention, it is also preferable that R ^c11 and R ^c12 are different groups, R ^c13 and R ^c14 are different groups, R ^c15 and R ^c16 are different groups, and R ^c17 and R ^c18 are different groups.

In formula (2), X ⁴ represents a sulfur atom or —NR ^N3 —.
In terms of obtaining superior effects of the present invention, ^X4 is preferably a sulfur atom.

R ^N3 represents a hydrogen atom or a substituent.
Examples of the substituent include the substituents exemplified for the substituent W described above.
More specifically, examples of the substituent include an alkyl group which may have a substituent, an alkenyl group which may have a substituent, an alkynyl group which may have a substituent, an aryl group which may have a substituent, or a heteroaryl group which may have a substituent.
R ^N3 is also preferably a group represented by Rt described below.
The definition and preferred embodiments of the group represented by R ^N3 are the same as those of the group represented by R ^N1 in formula (1).

In terms of the effects of the present invention being more excellent, in formula (1), X ¹ represents -C(R ^c1 Rs)-, -O-C(R ^c3 Rs)-, -Si(R ^c5 Rs)-, or -Ge(R ^c7 Rs)-, or X ² represents -NRt-;
In formula (2), it is also preferable that ^X3 represents -C( ^Rc11Rs )-, -O-C( ^Rc13Rs )-, -Si( ^Rc15Rs )-, or -Ge( ^Rc17Rs )-, ^X4 represents -NRt-, or R ^N2 represents Rt.

Each Rs independently represents an alkyl group which may have a substituent, an alkenyl group which may have a substituent, an alkynyl group which may have a substituent, an aryl group which may have a substituent, a heteroaryl group which may have a substituent, an alkoxy group which may have a substituent, an aryloxy group which may have a substituent, an amino group which may have a substituent, a cyano group, or a halogen atom.
Rs is preferably an alkyl group which may have a substituent, an alkenyl group which may have a substituent, an alkynyl group which may have a substituent, an aryl group which may have a substituent, a heteroaryl group which may have a substituent, an alkoxy group which may have a substituent, an aryloxy group which may have a substituent, or a halogen atom, and more preferably an alkyl group which may have a substituent, an alkenyl group which may have a substituent, an alkynyl group which may have a substituent, an aryl group which may have a substituent, a heteroaryl group which may have a substituent, or a halogen atom.
^The definitions and preferred embodiments of each group represented by Rs are the same as those of each group exemplified as the substituents represented by ^Rc1 , ^Rc2 , ^Rc3 , Rc4, ^Rc5 , ^Rc6 , ^Rc7 , and ^Rc8 described above.

Each Rt independently represents an alkyl group which may have a substituent, an alkenyl group which may have a substituent, an alkynyl group which may have a substituent, an aryl group which may have a substituent, or a heteroaryl group which may have a substituent.
Rt is preferably an alkyl group which may have a substituent, an aryl group which may have a substituent, or a heteroaryl group which may have a substituent, and more preferably an alkyl group which may have a substituent or an aryl group which may have a substituent.
The definitions and preferred embodiments of each group represented by Rt are the same as those of each group exemplified as the substituent represented by R ^N1 above.

The above-mentioned substituent group S will now be described in detail.
Substituent group S: linear aliphatic hydrocarbon groups having 1 to 6 carbon atoms, branched aliphatic hydrocarbon groups having 3 to 6 carbon atoms, cyclic aliphatic hydrocarbon groups having 3 to 6 carbon atoms, aromatic ring groups which may have a substituent, and halogen atoms.

The linear aliphatic hydrocarbon group in the above-mentioned substituent group S has 1 to 6 carbon atoms, preferably 1 to 4 carbon atoms, and more preferably 1 to 3 carbon atoms.
The branched aliphatic hydrocarbon group in the above-mentioned substituent group S has 3 to 6 carbon atoms, and more preferably 3 to 5 carbon atoms.
The cyclic aliphatic hydrocarbon group in the above-mentioned substituent group S is preferably a monocyclic group.

The aromatic ring group in the above-mentioned substituent group S may be either a monocyclic or polycyclic group, and is preferably a monocyclic group.
The aromatic ring group may be either an aromatic hydrocarbon group or an aromatic heterocyclic group, with an aromatic hydrocarbon group being preferred.
The aromatic ring group preferably has 5 to 12 ring atoms, and more preferably 5 or 6 ring atoms.
Examples of the substituent that the aromatic ring group may have include the substituents exemplified by the above-mentioned substituent W. Of these, a substituent selected from the substituent group S is preferable, and a linear aliphatic hydrocarbon group having 1 to 6 carbon atoms, a branched aliphatic hydrocarbon group having 3 to 6 carbon atoms, or a halogen atom is more preferable.
When the aromatic ring has a substituent, the number of the substituents is preferably 1 to 3.

Halogen atoms in the above-mentioned substituent group S include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms, with fluorine atoms and chlorine atoms being preferred.

In formula (2), ^A3 and ^A4 each independently represent a group represented by formula (A-1).

The group represented by formula (A-1) is described in detail below.

In formula (A-1), * indicates the bond position.

In formula (A-1), ^C1 represents a ring containing two or more carbon atoms which may have a substituent. The two carbon atoms contained in ^C1 are the two carbon atoms clearly shown in formula (A-1).
The number of carbon atoms in the ring is preferably 3 to 30, more preferably 3 to 20, and even more preferably 3 to 10. The number of carbon atoms in the ring is the number including the two carbon atoms specified in the formula.
The ring may be either an aromatic ring or a non-aromatic ring.
The ring may be either a monocycle or a polycycle, and is preferably a 5-membered ring, a 6-membered ring, or a fused ring containing at least one of a 5-membered ring and a 6-membered ring. The number of carbon atoms in the fused ring containing at least one of a 5-membered ring and a 6-membered ring is preferably 6 to 20, more preferably 6 to 15, and even more preferably 8 to 10.
The ring may have a heteroatom, such as a nitrogen atom, a sulfur atom, an oxygen atom, a selenium atom, a tellurium atom, a phosphorus atom, a silicon atom, or a boron atom, and is preferably a sulfur atom, a nitrogen atom, or an oxygen atom.
The number of heteroatoms in the ring is preferably 0 to 10, and more preferably 0 to 5.
Of the carbon atoms constituting the ring represented by ^C1 , carbon atoms other than the carbon atom at the bonding position marked with * in formula (A-1) and the carbon atom bonded to ^W1 may be substituted with a carbonyl carbon (>C=O) or a thiocarbonyl carbon (>C=S).

Examples of the substituent that the ring represented by ^C1 may have include the groups exemplified as the substituent W above. A halogen atom, an alkyl group, an aromatic ring group, a cyano group, or a silyl group is preferable, and a halogen atom or an alkyl group is more preferable.
The alkyl group may be linear, branched or cyclic, and is preferably linear.
The alkyl group preferably has 1 to 10 carbon atoms, and more preferably has 1 to 3 carbon atoms.

The ring represented by ^C1 above is preferably a ring used as an acidic nucleus (for example, an acidic nucleus in a merocyanine dye), and examples thereof include the following nuclei.
(a) 1,3-dicarbonyl nucleus: for example, a 1,3-indandione nucleus, 1,3-cyclohexanedione, 5,5-dimethyl-1,3-cyclohexanedione, 1,3-dioxane-4,6-dione, and the like.
(b) Pyrazolinone nucleus: for example, 1-phenyl-2-pyrazolin-5-one, 3-methyl-1-phenyl-2-pyrazolin-5-one, 1-(2-benzothiazolyl)-3-methyl-2-pyrazolin-5-one, and the like.
(c) Isoxazolinone nucleus: for example, 3-phenyl-2-isoxazolin-5-one, 3-methyl-2-isoxazolin-5-one, and the like.
(d) Oxindole nucleus: for example, 1-alkyl-2,3-dihydro-2-oxindole, etc.
(e) 2,4,6-trioxohexahydropyrimidine nucleus: for example, barbituric acid, 2-thiobarbituric acid, and derivatives thereof. Examples of the derivatives include 1-alkyl compounds such as 1-methyl and 1-ethyl, 1,3-dialkyl compounds such as 1,3-dimethyl, 1,3-diethyl, and 1,3-dibutyl, 1,3-diaryl compounds such as 1,3-diphenyl, 1,3-di(p-chlorophenyl), and 1,3-di(p-ethoxycarbonylphenyl), 1-alkyl-1-aryl compounds such as 1-ethyl-3-phenyl, and 1,3-diheteroaryl compounds such as 1,3-di(2-pyridyl).
(f) 2-thio-2,4-thiazolidinedione nucleus: for example, rhodanine and its derivatives, etc. Examples of the derivatives include 3-alkylrhodanines such as 3-methylrhodanine, 3-ethylrhodanine, and 3-allylrhodanine, 3-arylrhodanine such as 3-phenylrhodanine, and 3-heteroarylrhodanine such as 3-(2-pyridyl)rhodanine, etc.
(g) 2-thio-2,4-oxazolidinedione nucleus (2-thio-2,4-(3H,5H)-oxazoledione nucleus): for example, 3-ethyl-2-thio-2,4-oxazolidinedione.
(h) Thianaphthenone nucleus: for example, 3(2H)-thianaphthenone-1,1-dioxide.
(i) 2-thio-2,5-thiazolidinedione nucleus: for example, 3-ethyl-2-thio-2,5-thiazolidinedione, etc.
(j) 2,4-thiazolidinedione nucleus: for example, 2,4-thiazolidinedione, 3-ethyl-2,4-thiazolidinedione, and 3-phenyl-2,4-thiazolidinedione.
(k) Thiazolin-4-one nucleus: for example, 4-thiazolinone and 2-ethyl-4-thiazolinone.
(l) 2,4-imidazolidinedione (hydantoin) nucleus: for example, 2,4-imidazolidinedione and 3-ethyl-2,4-imidazolidinedione.
(m) 2-thio-2,4-imidazolidinedione (2-thiohydantoin) nucleus: for example, 2-thio-2,4-imidazolidinedione and 3-ethyl-2-thio-2,4-imidazolidinedione.
(n) Imidazolin-5-one nucleus: for example, 2-propylmercapto-2-imidazolin-5-one, etc.
(o) 3,5-pyrazolidinedione nucleus: for example, 1,2-diphenyl-3,5-pyrazolidinedione and 1,2-dimethyl-3,5-pyrazolidinedione.
(p) Benzothiophen-3(2H)-one nucleus: for example, benzothiophen-3(2H)-one, oxobenzothiophen-3(2H)-one, dioxobenzothiophen-3(2H)-one, and the like.
(q) Indanone nucleus: for example, 1-indanone, 3-phenyl-1-indanone, 3-methyl-1-indanone, 3,3-diphenyl-1-indanone, and 3,3-dimethyl-1-indanone.
(r) Benzofuran-3-(2H)-one nucleus: for example, benzofuran-3-(2H)-one, etc.
(s) 2,2-dihydrophenalene-1,3-dione nucleus, etc.

In formula (A-1), W ¹ represents an oxygen atom, a sulfur atom, ═NR ^W2 , or ═CR ^W3 R ^W4 .
W ¹ is preferably an oxygen atom or a sulfur atom, and more preferably an oxygen atom, in that the effects of the present invention are more excellent.
R ^W2 represents a hydrogen atom or a substituent. Examples of the substituent include the groups exemplified as the substituent W above.
R ^W3 and R ^W4 each independently represent a cyano group, —SO ₂ R ^W5 , —COOR ^W6 or —COR ^W7 .
R ^W5 to R ^W7 each independently represent an aliphatic hydrocarbon group which may have a substituent, an aromatic ring group which may have a substituent, or an aliphatic heterocyclic group which may have a substituent.
The aliphatic hydrocarbon group is as defined above, and an aliphatic hydrocarbon group having 1 to 3 carbon atoms is preferred.
The aromatic ring group is as defined above, and is preferably an aromatic hydrocarbon group, more preferably a phenyl group.
The aliphatic heterocyclic group is as defined above, and the heteroatom contained in the aliphatic heterocyclic group is preferably a sulfur atom, an oxygen atom, or a nitrogen atom.
Examples of the substituent that may be possessed by each of the groups represented by R ^W5 to R ^W7 include the substituents exemplified for the above-mentioned substituent W.

The group represented by formula (A-1) is preferably a group represented by formula (A-2) in that the effect of the present invention is more excellent.

In formula (A-2), * indicates the bond position.

In formula (A-2), ^C2 represents a ring containing at least 3 carbon atoms which may have a substituent.
The three carbon atoms included in the above ^C2 are the three carbon atoms clearly shown in formula (A-2).
The number of carbon atoms in the ring is preferably 3 to 30, more preferably 3 to 20, and even more preferably 3 to 10. The number of carbon atoms in the ring is the number including the three carbon atoms specified in the formula.
The ring may be either an aromatic ring or a non-aromatic ring.
The ring may be either a monocycle or a polycycle, and is preferably a 5-membered ring, a 6-membered ring, or a fused ring containing at least one of a 5-membered ring and a 6-membered ring. The number of carbon atoms in the fused ring containing at least one of a 5-membered ring and a 6-membered ring is preferably 6 to 20, more preferably 6 to 15, and even more preferably 8 to 10.
The ring may have a heteroatom, such as a nitrogen atom, a sulfur atom, an oxygen atom, a selenium atom, a tellurium atom, a phosphorus atom, a silicon atom, or a boron atom, and is preferably a sulfur atom, a nitrogen atom, or an oxygen atom.
The number of heteroatoms contained in the ring is preferably 0 to 10, and more preferably 0 to 5.
Of the carbon atoms constituting the ring represented by ^C2 , the carbon atoms other than the carbon atom at the bonding position marked with * in formula (A-2) and the carbon atom bonded to ^Y2 or ^Y3 may be substituted with a carbonyl carbon (>C=O) or a thiocarbonyl carbon (>C=S).
Preferred embodiments of the substituent that the above ring may have are the same as the substituent that the above ring ^C1 may have.

In formula (A-2), W ² and W ³ each independently represent an oxygen atom or a sulfur atom, and preferably an oxygen atom in that the effects of the present invention are more excellent.

The group represented by formula (A-2) is preferably a group represented by formula (C-1) or a group represented by formula (C-2), and more preferably a group represented by formula (C-2), in that the effects of the present invention are more excellent.

In formula (C-1), * indicates the bond position.

In formula (C-1), ^Xc1 and ^Xc2 each independently represent an oxygen atom or a sulfur atom.
In terms of superior effects of the present invention, it is preferable that either ^Xc1 or ^Xc2 is an oxygen atom, and it is more preferable that both ^Xc1 and ^Xc2 are oxygen atoms.

In formula (C-1), ^C3 represents an aromatic ring which may have a substituent.
The aromatic ring may be either a monocyclic ring or a polycyclic ring.
The number of member atoms of the aromatic ring is preferably 4 to 30, more preferably 5 to 12, and even more preferably 5 to 8. The number of member atoms of the aromatic ring is the number including the two carbon atoms specified in the formula.
The aromatic ring may be either an aromatic hydrocarbon ring or an aromatic heterocycle, with an aromatic hydrocarbon ring being preferred.
The aromatic ring represented by ^C3 is as described above, and is preferably a benzene ring, a naphthalene ring, an anthracene ring, a pyrene ring, a thiophene ring, a furan ring, a thiazole ring, an oxazole ring, a pyridine ring, a thienothiophene ring, a benzothiophene ring, a benzofuran ring, a pyrazine ring, a pyrimidine ring, or a pyridazine ring, more preferably a benzene ring, a naphthalene ring, or a thiophene ring, and further preferably a benzene ring.
Examples of the substituent that the aromatic ring may have include the groups exemplified as the substituent W above, and an alkyl group or a halogen atom is preferred.
The number of substituents that the aromatic ring may have is not particularly limited, but is preferably 0 to 8, and more preferably 0 to 4.

In formula (C-2), * indicates the bond position.

In formula (C-2), X ^c3 to X ^c5 each independently represent an oxygen atom or a sulfur atom.
In terms of obtaining superior effects of the present invention, it is preferable that X ^c3 and X ^c4 are oxygen atoms, and it is more preferable that X ^c3 to X ^c5 are oxygen atoms.

In formula (C-2), R ^c1 and R ^c2 each independently represent a hydrogen atom or a substituent.
Examples of the substituent include the groups exemplified as the substituent W above, and an alkyl group or an aryl group is preferable, and an alkyl group is more preferable.
The alkyl group may be linear, branched, or cyclic, and is preferably linear. The alkyl group preferably has 1 to 20 carbon atoms, more preferably 1 to 6 carbon atoms, still more preferably 1 to 3 carbon atoms, and particularly preferably 1 or 2 carbon atoms.
The aryl group may be either a monocyclic or polycyclic ring, and is preferably a phenyl group. The aryl group may further have a substituent, and examples of the substituent include the groups exemplified by the substituent W.

Specific examples of specific compounds are given below, but the present invention is not limited to these.

In the specific compounds exemplified above, A represents any one of the following groups.
In addition, the two A's present in the specific compounds exemplified above may be the same or different.

The molecular weight of the specific compound is preferably from 300 to 1,200, more preferably from 350 to 1,000, and even more preferably from 400 to 800.
When the molecular weight is within the above range, it is presumed that the sublimation temperature of the specific compound is low, resulting in excellent suitability for production.

In terms of stability when used as a p-type organic semiconductor and matching of the energy level with n-type organic semiconductors, it is preferable that the specific compound has an ionization potential of -5.0 to -6.0 eV in a single film.

The maximum absorption wavelength of the specific compound is preferably in the range of 450 to 800 nm, and more preferably in the range of 500 to 650 nm.
The maximum absorption wavelength is a value measured in a solution state (solvent: chloroform) by adjusting the absorption spectrum of the specific compound to a concentration such that the absorbance is 0.5 to 1.0. However, if the specific compound is not soluble in chloroform, the specific compound is evaporated and the value measured using the specific compound in a film state is regarded as the maximum absorption wavelength of the specific compound.

The specific compounds are particularly useful as materials for photoelectric conversion films used in imaging devices, photosensors, or photovoltaic cells. The specific compounds often function as dyes within the photoelectric conversion films. The specific compounds can also be used as coloring materials, liquid crystal materials, organic semiconductor materials, charge transport materials, medicinal materials, and fluorescent diagnostic materials.

The particular compound may be purified if necessary.
Examples of methods for purifying the specific compound include sublimation purification, purification using silica gel column chromatography, purification using gel permeation chromatography, reslurry washing, reprecipitation purification, purification using an adsorbent such as activated carbon, and recrystallization purification.

The content of the specific compound in the photoelectric conversion film (=film thickness of the specific compound in terms of a single layer/film thickness of the photoelectric conversion film×100) is not particularly limited, but is preferably 5 to 75 vol%, more preferably 10 to 50 vol%, and even more preferably 15 to 40 vol%.
The specific compound may be used alone or in combination of two or more. When two or more types are used, the total amount thereof is preferably within the above range.

<n-type organic semiconductor>
The photoelectric conversion film preferably contains an n-type organic semiconductor in addition to the specific compound.
The n-type organic semiconductor is a compound different from the above specific compound.
An n-type organic semiconductor is an acceptor organic semiconductor material (compound) that is an organic compound that has the property of easily accepting electrons. In other words, an n-type organic semiconductor is an organic compound that has a larger electron affinity when two organic compounds are used in contact with each other. In other words, any organic compound that has electron accepting properties can be used as an acceptor organic semiconductor.
Examples of n-type organic semiconductors include fullerenes selected from the group consisting of fullerenes and derivatives thereof; condensed aromatic carbon ring compounds (e.g., naphthalene derivatives, anthracene derivatives, phenanthrene derivatives, tetracene derivatives, pyrene derivatives, perylene derivatives, and fluoranthene derivatives); 5- to 7-membered heterocyclic compounds having at least one selected from the group consisting of nitrogen atoms, oxygen atoms, and sulfur atoms (e.g., pyridine, pyrazine, pyrimidine, pyridazine, triazine, quinoline, quinoxaline, quinazoline, phthalazine, cinnoline, isoquinoline, pteridine, acridine, phenazine, phenanthroline, tetrazole, pyridine ... Examples of suitable aryl compounds include 1,4,5,8-naphthalenetetracarboxylic anhydride, 1,4,5,8-naphthalenetetracarboxylic anhydride imide derivatives and oxadiazole derivatives, anthraquinodimethane derivatives, diphenylquinone derivatives, bathocuproine, bathophenanthroline, and derivatives thereof, triazole compounds, distyrylarylene derivatives, metal complexes having a nitrogen-containing heterocyclic compound as a ligand, silole compounds, and the compounds described in paragraphs [0056] to [0057] of JP2006-100767A.

As the n-type organic semiconductor (compound), fullerenes selected from the group consisting of fullerene and derivatives thereof are preferred.
Examples of fullerenes include fullerene _C60 , fullerene _C70 , fullerene _C76 , fullerene _C78 , fullerene _C80 , fullerene _C82 , fullerene _C84 , fullerene _C90 , fullerene _C96 , fullerene _C240 , fullerene _C540 , and mixed fullerenes.
The fullerene derivative may be, for example, a compound in which a substituent is added to the fullerene. The substituent is preferably an alkyl group, an aryl group, or a heterocyclic group. The fullerene derivative is preferably a compound described in JP-A-2007-123707.

The molecular weight of the n-type organic semiconductor is preferably 200 to 1,200, and more preferably 200 to 900.

The maximum absorption wavelength of the n-type organic semiconductor is preferably 400 nm or less or in the range of 500 to 600 nm.

The photoelectric conversion film preferably has a bulk heterostructure formed by mixing a specific compound with an n-type organic semiconductor. The bulk heterostructure is a layer in the photoelectric conversion film in which a specific compound and an n-type organic semiconductor are mixed and dispersed. A photoelectric conversion film having a bulk heterostructure can be formed by either a wet method or a dry method. The bulk heterostructure is described in detail in paragraphs [0013] to [0014] of JP 2005-303266 A.

The difference in electron affinity between the specific compound and the n-type organic semiconductor is preferably 0.1 eV or more.

The n-type organic semiconductor may be used alone or in combination of two or more.
When the photoelectric conversion film contains an n-type organic semiconductor, the content of the n-type organic semiconductor in the photoelectric conversion film (film thickness of the n-type organic semiconductor in terms of a single layer/film thickness of the photoelectric conversion film×100) is preferably 15 to 75 vol%, more preferably 20 to 60 vol%, and even more preferably 20 to 50 vol%.

When the n-type organic semiconductor contains fullerenes, the content of fullerenes relative to the total content of n-type organic semiconductors (film thickness of fullerenes converted into a single layer/total film thickness of each n-type organic semiconductor converted into a single layer x 100) is preferably 50 to 100 volume %, more preferably 80 to 100 volume %. Fullerenes may be used alone or in combination of two or more types.

In terms of the response speed of the photoelectric conversion element, the content of the specific compound relative to the total content of the specific compound and the n-type organic semiconductor (film thickness of the specific compound in terms of a single layer/(film thickness of the specific compound in terms of a single layer+film thickness of the n-type organic semiconductor in terms of a single layer)×100) is preferably 20 to 80 vol%, and more preferably 40 to 80 vol%.
When the photoelectric conversion film contains an n-type organic semiconductor and a p-type organic semiconductor, the content of the specific compound (film thickness of the specific compound in terms of a single layer/(film thickness of the specific compound in terms of a single layer+film thickness of the n-type organic semiconductor in terms of a single layer+film thickness of the p-type organic semiconductor in terms of a single layer)×100) is preferably 10 to 75 vol%, and more preferably 15 to 50 vol%.
It is preferable that the photoelectric conversion film is substantially composed of the specific compound, the n-type organic semiconductor, and the p-type organic semiconductor contained as desired. By "substantially," it is meant that the total content of the specific compound, the n-type organic semiconductor, and the p-type organic semiconductor relative to the total mass of the photoelectric conversion film is 90 to 100 volume %, preferably 95 to 100 volume %, and more preferably 99 to 100 volume %.

<p-type organic semiconductor>
The photoelectric conversion film preferably contains a p-type organic semiconductor in addition to the specific compound.
The p-type organic semiconductor is a compound different from the above specific compound.
A p-type organic semiconductor is a donor organic semiconductor material (compound) that has the property of easily donating electrons. In other words, a p-type organic semiconductor is an organic compound that has a smaller ionization potential when two organic compounds are used in contact with each other.
The p-type organic semiconductor may be used alone or in combination of two or more.

Examples of p-type organic semiconductors include triarylamine compounds (e.g., N,N'-diphenyl-N,N'-bis(3-methylphenyl)-(1,1'-biphenyl)-4,4'-diamine (TPD), 4,4'-bis[N-(naphthyl)-N-phenyl-amino]biphenyl (α-NPD), compounds described in paragraphs [0128] to [0148] of JP-A No. 2011-228614, compounds described in paragraphs [0052] to [0063] of JP-A No. 2011-176259, compounds described in paragraphs [0064] to [0065] of JP-A No. 2011-225 compounds described in paragraphs [0119] to [0158] of JP-A No. 544, compounds described in paragraphs [0044] to [0051] of JP-A No. 2015-153910, and compounds described in paragraphs [0086] to [0090] of JP-A No. 2012-094660, etc.), pyrazoline compounds, styrylamine compounds, hydrazone compounds, polysilane compounds, thiophene compounds (e.g., thienothiophene derivatives, dibenzothiophene derivatives, benzodithiophene derivatives, dithienothiophene derivatives, [1]benzothi eno[3,2-b][1]benzothiophene (BTBT) derivatives, thieno[3,2-f:4,5-f']bis[1]benzothiophene (TBBT) derivatives, compounds described in paragraphs [0031] to [0036] of JP2018-014474A, compounds described in paragraphs [0043] to [0045] of WO2016/194630, compounds described in paragraphs [0025] to [0037] and [0099] to [0109] of WO2017/159684, compounds described in paragraphs [0025] to [0037] and [0099] to [0109] of JP2017-076766A, 029] to [0034], the compounds described in paragraphs [0015] to [0025] of WO2018/207722, the compounds described in paragraphs [0045] to [0053] of JP2019-054228A, the compounds described in paragraphs [0045] to [0055] of WO2019/058995, the compounds described in paragraphs [0063] to [0089] of WO2019/081416, the compounds described in paragraphs [0033] to [0036] of JP2019-80052A, W2019/0541 Compounds described in paragraphs [0044] to [0054] of No. 25, compounds described in paragraphs [0041] to [0046] of WO2019/093188, compounds of paragraphs [0034] to [0037] of JP-A-2019-050398, compounds of paragraphs [0033] to [0036] of JP-A-2018-206878, compounds of paragraphs [0038] of JP-A-2018-190755, compounds of paragraphs [0019] to [0021] of JP-A-2018-026559, and JP-A-2018-170487 the compounds of paragraphs [0031] to [0056] of JP 2018-078270 A, the compounds of paragraphs [0036] to [0041] of JP 2018-166200 A, the compounds of paragraphs [0055] to [0082] of JP 2018-113425 A, the compounds of paragraphs [0041] to [0050] of JP 2018-085430 A, the compounds of paragraphs [0044] to [0048] of JP 2018-056546 A, the compounds of paragraphs [0041] to [0045] of JP 2018-046267 A The compounds described in paragraphs [0042] to [0049] of JP 2018-014474 A, the compounds described in paragraphs [0031] to [0036] of WO 2018/016465 A, and the compounds described in paragraphs [0036] to [0046] of JP 2020-010024 A, cyanine compounds, oxonol compounds, polyamine compounds, indole compounds, pyrrole compounds, pyrazole compounds, polyarylene compounds, condensed aromatic carbocyclic compounds (e.g., naphthalene derivatives, anthracene derivatives, phenanthrene derivatives, tetracene derivatives, pentacene derivatives, pyrene derivatives, perylene derivatives, fluoranthene derivatives, etc.), porphyrin compounds, phthalocyanine compounds, triazole compounds, oxadiazole compounds, imidazole compounds, polyarylalkane compounds, pyrazolone compounds, amino-substituted chalcone compounds, oxazole compounds, fluorenone compounds, silazane compounds, and metal complexes having nitrogen-containing heterocyclic compounds as ligands.
Examples of p-type organic semiconductors include benzoxazole compounds (e.g., compounds described in Figures 3 to 7 of JP-A-2022-123944), dicarbazole compounds (e.g., compounds described in Figures 2 to 5 of JP-A-2022-122839), benzoquinazoline compounds (e.g., compounds described in paragraphs [0053] to [0056] of JP-A-2022-120323), azine compounds (e.g., compounds described in paragraphs [0053] to [0056] of JP-A-2022-12027), and the like. Also included are compounds described in paragraphs [0041] to [0042] of JP-A-2022-115832, compounds described in Figures 2 to 10 of JP-A-2022-108268, indolotriphenylene compounds (for example, compounds described in paragraphs [0065] to [0072] of JP-A-2022-108268), and indolocarbazole compounds (for example, compounds described in paragraphs [0052] to [0073] of JP-A-2023-005703).
Examples of p-type organic semiconductors include compounds having a smaller ionization potential than n-type organic semiconductors. If this condition is satisfied, the organic dyes exemplified as n-type organic semiconductors can be used.
Examples of compounds that can be used as the p-type organic semiconductor compound are given below.

The difference in ionization potential between the specific compound and the p-type organic semiconductor is preferably 0.1 eV or more.

The p-type organic semiconductor material may be used alone or in combination of two or more.
When the photoelectric conversion film contains a p-type organic semiconductor, the content of the p-type organic semiconductor in the photoelectric conversion film (film thickness of the p-type organic semiconductor in terms of a single layer/film thickness of the photoelectric conversion film×100) is preferably 15 to 75 vol%, more preferably 20 to 60 vol%, and even more preferably 25 to 50 vol%.

The photoelectric conversion film containing a specific compound is a non-luminescent film, and has characteristics different from those of an organic electroluminescent device (OLED: Organic Light Emitting Diode). A non-luminescent film means a film with a luminescent quantum efficiency of 1% or less, preferably 0.5% or less, and more preferably 0.1% or less. The lower limit is often 0% or more.

<Dye>
The photoelectric conversion film preferably contains a dye in addition to the specific compound.
The dye is a compound different from the above specific compound.
The dye is preferably an organic dye.
Examples of organic dyes include cyanine dyes, styryl dyes, hemicyanine dyes, merocyanine dyes (including zeromethine merocyanine (simple merocyanine)), rhodacyanine dyes, allopolar dyes, oxonol dyes, hemioxonol dyes, squarylium dyes, croconium dyes, azamethine dyes, coumarin dyes, arylidene dyes, anthraquinone dyes, triphenylmethane dyes, azo dyes, azomethine dyes, metallocene dyes, fluorenone dyes, fulgide dyes, perylene dyes, phenazine dyes, phenothiazine dyes, quinone dyes, diphenylmethane dyes, polyene dyes, acridine dyes, Cridinone dyes, diphenylamine dyes, quinophthalone dyes, phenoxazine dyes, phthaloperylene dyes, dioxane dyes, porphyrin dyes, chlorophyll dyes, phthalocyanine dyes, subphthalocyanine dyes, metal complex dyes, WO2020/013246, WO2022/168856, JP2023-010305A, and JP2023-010299A described imidazoquinoxaline dyes, acceptor-donor-acceptor type dyes in which two acidic nuclei are bonded to a donor, and donor-acceptor-donor type dyes in which two donors are bonded to an acceptor, etc. Among them, in terms of maximum absorption wavelength, cyanine dyes, imidazoquinoxaline dyes, or acceptor-donor-acceptor type dyes are preferred.

The maximum absorption wavelength of the dye is preferably in the visible light region, more preferably in the wavelength range of 400 to 650 nm, and even more preferably in the wavelength range of 400 to 550 nm.

The dyes may be used alone or in combination of two or more.
The content of the dye in the photoelectric conversion film relative to the total content of the specific compound and the dye (=(film thickness of the dye in monolayer equivalent/(film thickness of the specific compound in monolayer equivalent+film thickness of the dye in monolayer equivalent)×100) is preferably 5 to 75 vol%, more preferably 5 to 60 vol%, and even more preferably 5 to 50 vol%.

<Film formation method>
The photoelectric conversion film may be formed, for example, by a dry film formation method.
Examples of the dry film formation method include physical vapor deposition methods such as vapor deposition (particularly vacuum deposition), sputtering, ion plating, and MBE (Molecular Beam Epitaxy), and CVD (Chemical Vapor Deposition) methods such as plasma polymerization, and the vacuum deposition method is preferred. When forming the photoelectric conversion film by the vacuum deposition method, the manufacturing conditions such as the degree of vacuum and the deposition temperature can be set according to a conventional method.

The thickness of the photoelectric conversion film is preferably 10 to 1000 nm, more preferably 50 to 800 nm, and even more preferably 50 to 500 nm.

〔electrode〕
The photoelectric conversion element preferably has an electrode.
The electrodes (upper electrode (transparent conductive film) 15 and lower electrode (conductive film) 11) are made of a conductive material. Examples of the conductive material include metals, alloys, metal oxides, electrically conductive compounds, and mixtures thereof.
Since light is incident from the upper electrode 15, the upper electrode 15 is preferably transparent to the light to be detected. Examples of materials constituting the upper electrode 15 include conductive metal oxides such as antimony- or fluorine-doped tin oxide (ATO: Antimony Tin Oxide, FTO: Fluorine doped Tin Oxide), tin oxide, zinc oxide, indium oxide, indium tin oxide (ITO: Indium Tin Oxide), and indium zinc oxide (IZO: Indium zinc oxide); thin metal films such as gold, silver, chromium, and nickel; mixtures or laminates of these metals and conductive metal oxides; and organic conductive materials such as polyaniline, polythiophene, and polypyrrole, nanocarbon materials such as carbon nanotubes and graphene, and the like. In terms of high conductivity and transparency, conductive metal oxides are preferred.

Generally, when a conductive film is made thinner than a certain range, the resistance value often increases rapidly. In a solid-state imaging device incorporating a photoelectric conversion element according to this embodiment, the sheet resistance may be 100 to 10,000 Ω/□, and there is a large degree of freedom in the range of the film thickness that can be thinned.
Furthermore, the thinner the upper electrode (transparent conductive film) 15 is, the less light it absorbs, and generally the higher the light transmittance. An increase in light transmittance is preferable because it increases the light absorption in the photoelectric conversion film and increases the photoelectric conversion ability. Considering the suppression of leakage current, the increase in the resistance value of the thin film, and the increase in transmittance that accompany a thinner film, the thickness of the upper electrode 15 is preferably 5 to 100 nm, and more preferably 5 to 20 nm.

Depending on the application, the lower electrode 11 may be made transparent or may be made non-transparent and reflective. Materials constituting the lower electrode 11 include, for example, conductive metal oxides such as tin oxide doped with antimony or fluorine (ATO, FTO), tin oxide, zinc oxide, indium oxide, indium tin oxide (ITO), and indium zinc oxide (IZO); metals such as gold, silver, chromium, nickel, titanium, tungsten, and aluminum; conductive compounds such as oxides or nitrides of these metals (for example, titanium nitride (TiN)); mixtures or laminates of these metals and conductive metal oxides; organic conductive materials such as polyaniline, polythiophene, and polypyrrole; and carbon materials such as carbon nanotubes and graphene.

The method for forming the electrodes can be appropriately selected depending on the electrode material. Specific examples include wet methods such as printing and coating, physical methods such as vacuum deposition, sputtering, and ion plating, and chemical methods such as CVD and plasma CVD.
When the electrode material is ITO, methods such as an electron beam method, a sputtering method, a resistance heating deposition method, a chemical reaction method (such as a sol-gel method), and coating of a dispersion of indium tin oxide can be used.

[Charge blocking film: electron blocking film, hole blocking film]
The photoelectric conversion element preferably has one or more intermediate layers between the conductive film and the transparent conductive film in addition to the photoelectric conversion film.
The intermediate layer may be, for example, a charge blocking film. When the photoelectric conversion element has this film, the characteristics (quantum efficiency, response speed, etc.) of the obtained photoelectric conversion element are more excellent. The charge blocking film may be, for example, an electron blocking film or a hole blocking film.

<Electron blocking film>
The electron blocking film is a donor organic semiconductor material (compound), and the above-mentioned p-type organic semiconductor can be used.
Furthermore, polymeric materials can also be used as the electron blocking film.
Examples of the polymeric material include polymers of phenylenevinylene, fluorene, carbazole, indole, pyrene, pyrrole, picoline, thiophene, acetylene, and diacetylene, and derivatives thereof.

The electron blocking film may be made up of multiple films.
The electron blocking film may be made of an inorganic material. In general, inorganic materials have a higher dielectric constant than organic materials, so when an inorganic material is used for the electron blocking film, a higher voltage is applied to the photoelectric conversion film, and the quantum efficiency is increased. Examples of inorganic materials that can be used for the electron blocking film include calcium oxide, chromium oxide, copper chromium oxide, manganese oxide, cobalt oxide, nickel oxide, copper oxide, copper gallium oxide, copper strontium oxide, niobium oxide, molybdenum oxide, copper indium oxide, silver indium oxide, and iridium oxide.

<Hole blocking film>
The hole blocking film is an acceptor organic semiconductor material (compound), and the above-mentioned n-type organic semiconductor can be used.
The hole blocking film may be made up of multiple films.

Methods for manufacturing the charge blocking film include, for example, a dry film formation method and a wet film formation method. Examples of dry film formation methods include a vapor deposition method and a sputtering method. The vapor deposition method may be either a physical vapor deposition (PVD) method or a chemical vapor deposition (CVD) method, with a physical vapor deposition method such as a vacuum vapor deposition method being preferred. Examples of wet film formation methods include an inkjet method, a spray method, a nozzle print method, a spin coat method, a dip coat method, a cast method, a die coat method, a roll coat method, a bar coat method, and a gravure coat method, with the inkjet method being preferred in terms of high-precision patterning.

The thickness of each of the charge blocking films (electron blocking film and hole blocking film) is preferably 3 to 200 nm, more preferably 5 to 100 nm, and even more preferably 5 to 30 nm.

〔substrate〕
The photoelectric conversion element may further include a substrate.
Examples of the substrate include a semiconductor substrate, a glass substrate, and a plastic substrate.
Regarding the position of the substrate, the conductive film, the photoelectric conversion film, and the transparent conductive film are usually laminated on the substrate in this order.

[Sealing layer]
The photoelectric conversion element may further include a sealing layer.
The performance of photoelectric conversion materials may be significantly deteriorated in the presence of deterioration factors such as water molecules, etc. Therefore, the deterioration can be prevented by covering and sealing the entire photoelectric conversion film with a sealing layer such as ceramics such as dense metal oxide, metal nitride, or metal nitride oxide, which does not allow water molecules to penetrate, or diamond-like carbon (DLC).
The sealing layer is described, for example, in paragraphs [0210] to [0215] of JP-A-2011-082508, the contents of which are incorporated herein by reference.

[Method of manufacturing photoelectric conversion element]
The photoelectric conversion element can be produced by a known production method.
Specifically, for example, there is mentioned a method for producing a photoelectric conversion element, which includes a step of forming a conductive film on a substrate, a step of forming a photoelectric conversion film, and a step of forming a transparent conductive film.
The method for producing a photoelectric conversion element may include other steps in addition to those described above (for example, a step of forming a charge blocking film and a step of forming a sealing layer).
The method for forming each layer is as described above.

[Image sensor]
Photoelectric conversion elements are used, for example, as imaging elements.
An imaging element is an element that converts the optical information of an image into an electrical signal, and is usually configured with multiple photoelectric conversion elements arranged in a matrix on the same plane, with each photoelectric conversion element (pixel) converting the optical signal into an electrical signal, and outputting the electrical signal pixel by pixel from the imaging element. For this reason, each pixel is composed of one or more photoelectric conversion elements and one or more transistors.
The method for producing the imaging element is not particularly limited, but may be a method including the step of producing the above-mentioned photoelectric conversion element.

[Optical sensor]
Other applications of the photoelectric conversion element include, for example, a photocell and an optical sensor, and the photoelectric conversion element of the present invention is preferably used as an optical sensor. As an optical sensor, the photoelectric conversion element may be used alone, or the photoelectric conversion element may be used as a line sensor in which the photoelectric conversion elements are arranged in a straight line, or as a two-dimensional sensor in which the photoelectric conversion elements are arranged on a plane.

[Compound]
The present invention also includes inventions of specific compounds.

The present invention will be described in further detail below with reference to examples.
The materials, amounts, ratios, processing contents, processing procedures, etc. shown in the following examples can be appropriately changed without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be interpreted as being limited by the following examples.

[Compounds used in photoelectric conversion film]
The materials used in the photoelectric conversion film are listed below.

[Synthesis of compound (1)]
Compound (1) was synthesized according to the following scheme.

Compound (1-1) (250 mg, 1.02 mmol), 1,3-dimethylbarbituric acid (336 mg, 2.15 mmol), toluene (25 mL), and piperidine (20.1 μL, 0.172 mmol) were mixed to obtain a mixed solution. The mixed solution was stirred at 100° C. for 4 hours and then allowed to cool to room temperature. The precipitated solid was filtered off, and the obtained crude product was washed successively with tetrahydrofuran (THF), dimethylacetamide (DMAc), and THF. The obtained solid was dried under reduced pressure at 200° C. and purified by sublimation to obtain 477 mg of compound (1) (yield 90%).
The structure of compound (1) was confirmed by LDI-MS.
LDI-MS (compound (1)): 522 (M+)

The compounds used in the photoelectric conversion film in each of the examples and comparative examples other than compound (1) were synthesized according to the synthesis method of compound (1).

[Specific Compound]
The specific compounds used in the photoelectric conversion film and the comparative compounds used as comparative examples are shown below.
The compounds (1) to (11) are specific compounds, and the compounds (R-1) to (R-2) are comparative compounds.

[n-type organic semiconductor]
・C60: Fullerene ( _C60 )

[p-type organic semiconductor]

[Pigment]

[evaluation]
[Test X]
The photoelectric conversion element was evaluated for quantum efficiency when receiving green-red light (light with a wavelength of 560 nm), response speed, and electric field strength dependency of the response speed, as well as manufacturability, by the following methods.

[Fabrication of photoelectric conversion element]
Using the various components shown above, a photoelectric conversion element having the configuration shown in Fig. 2 was produced. Here, the photoelectric conversion element comprises a lower electrode 11, an electron blocking film 16A, a photoelectric conversion film 12, a hole blocking film 16B and an upper electrode 15.
Specifically, amorphous ITO was formed on a glass substrate by sputtering to form a lower electrode 11 (thickness: 30 nm), and a compound (EB-1) was further formed on the lower electrode 11 by vacuum heating deposition to form an electron blocking film 16A (thickness: 30 nm).
Next, with the glass substrate at room temperature, each specific compound or each comparative compound shown in Table 1, an n-type organic semiconductor (fullerene (C ₆₀ )), and a p-type organic semiconductor (P-1) were co-evaporated by vacuum evaporation onto the electron blocking film 16A so as to have a thickness of 80 nm in terms of a single layer. This resulted in the formation of a photoelectric conversion film 12 having a bulk heterostructure of 240 nm. At this time, the film formation speed of the photoelectric conversion film 12 was set to 1.0 Å/sec.
Further, a compound (EB-2) was deposited on the photoelectric conversion film 12 to form a hole blocking film 16B (thickness: 10 nm). Amorphous ITO was deposited on the hole blocking film 16B by sputtering to form an upper electrode 15 (transparent conductive film) (thickness: 10 nm). After a SiO film was formed as a sealing layer on the upper electrode 15 by vacuum deposition, an aluminum oxide (Al ₂ O ₃ ) layer was formed thereon by atomic layer chemical vapor deposition (ALCVD), and the resulting laminate was heated at 150° C. for 30 minutes in a glove box to obtain a photoelectric conversion element.

[Dark current]
For each of the obtained photoelectric conversion elements, the dark current was measured by the following method.
A voltage was applied to the lower and upper electrodes of each photoelectric conversion element to achieve an electric field strength of 2.5×10 ⁵ V/cm, and the current value in a dark place (dark current) was measured. As a result, it was confirmed that the dark current in each photoelectric conversion element was 50 nA/cm ² or less, which is a sufficiently low dark current.

[Quantum efficiency]
For each photoelectric conversion element, the quantum efficiency when green and red light was received was measured by the following method.
A voltage was applied to each photoelectric conversion element so as to achieve an electric field strength of 2.5×10 ⁵ V/cm, and then light was irradiated from the upper electrode (transparent conductive film) side to evaluate the quantum efficiency (photoelectric conversion efficiency) at a wavelength of 560 nm. As a result, it was confirmed that the quantum efficiency was 50% or more in all photoelectric conversion elements.

[Response speed]
The response speed of each photoelectric conversion element when receiving green and red light was evaluated by the following method.
A voltage was applied to the photoelectric conversion element so that the electric field intensity was 2.5×10 ⁵ V/cm. Then, the LED (light emitting diode) was turned on instantaneously to irradiate light from the upper electrode (transparent conductive film) side, and the photocurrent at a wavelength of 560 nm at that time was measured with an oscilloscope to measure the rise time from 0% signal intensity to 97% signal intensity, and the relative response speed was calculated according to formula (S2). From the obtained value, the response speed was evaluated according to the following evaluation criteria. For practical purposes, the response speed is preferably evaluated as C or higher.
Equation (S2): Relative response speed = (rise time of each photoelectric conversion element) / (rise time of the photoelectric conversion element of Example 5)

A: Relative response speed is less than 1.0 B: Relative response speed is 1.0 or more and less than 1.5 C: Relative response speed is 1.5 or more and less than 2.0 D: Relative response speed is 2.0 or more and less than 3.0 E: Relative response speed is 3.0 or more

[Response speed dependence on electric field strength]
For each photoelectric conversion element, the dependence of the response speed on the electric field strength when green and red light was received was evaluated by the following method.
In the evaluation of the response speed, the rise time was measured at 7.5×10 ⁴ V/cm in the same manner as above, except that the voltage applied to each photoelectric conversion element was changed to 7.5×10 ⁴ V/cm.
The electric field strength dependency of the response speed was calculated according to formula (S3), and the electric field strength dependency of the response speed was evaluated according to the following evaluation criteria. In formula (S3), the numerator and denominator are values measured for the photoelectric conversion element of the same Example or Comparative Example. For practical purposes, the electric field strength dependency of the response speed is preferably rated C or higher.
Equation (S3): Dependence of response speed on electric field strength=(rise time of each photoelectric conversion element at an applied voltage of 7.5×10 ⁴ V/cm)/(rise time of each photoelectric conversion element at an applied voltage of 2.5×10 ⁵ V/cm)

A: The electric field strength dependency of the response speed is less than 3.0. B: The electric field strength dependency of the response speed is 3.0 or more and less than 4.0. C: The electric field strength dependency of the response speed is 4.0 or more and less than 5.0. D: The electric field strength dependency of the response speed is 5.0 or more and less than 6.0. E: The electric field strength dependency of the response speed is 6.0 or more.

[Manufacturing suitability]
The manufacturability of each photoelectric conversion element was evaluated by the following method.
Photoelectric conversion elements (B) of each Example or Comparative Example were produced in the same manner as in the above [Production of photoelectric conversion element], except that the deposition rate of the photoelectric conversion film 12 was set to 3.0 Å/sec. The quantum efficiency (photoelectric conversion efficiency) of the obtained photoelectric conversion element (B) was measured in the same manner as in the above [Quantum efficiency].
The photoelectric conversion element obtained in the above [Preparation of photoelectric conversion element], in which the deposition rate of the photoelectric conversion film 12 was 1.0 Å/sec, was designated as photoelectric conversion element (A), and the relative ratio B/A of quantum efficiency (photoelectric conversion efficiency) was calculated according to formula (S4). From the obtained value, the manufacturability was evaluated according to the following evaluation criteria. In formula (S4), the photoelectric conversion element (B) and the photoelectric conversion element (A) in the numerator and denominator are photoelectric conversion elements prepared using the same material.
The closer the value of the relative ratio B/A is to 1, the less the performance of the photoelectric conversion element is likely to deteriorate even when the film formation speed is increased, that is, the more excellent the manufacturability. In practical terms, the manufacturability is preferably evaluated as C or higher.
Formula (S4): Relative ratio B/A=(photoelectric conversion efficiency of photoelectric conversion element (B))/(photoelectric conversion efficiency of photoelectric conversion element (A))

A: The relative ratio B/A is 0.90 or more. B: The relative ratio B/A is 0.85 or more and less than 0.90. C: The relative ratio B/A is 0.80 or more and less than 0.85. D: The relative ratio B/A is less than 0.80.

[Results]

The evaluation results are shown in Table 1 below.
In the table, the column "Formula (1), Formula (2)" indicates that the photoelectric conversion film contains a compound represented by formula (1) and that the photoelectric conversion film contains a compound represented by formula (2), and indicates that the photoelectric conversion film contains a compound represented by formula (2).
In the table, the "X ² " column indicates that in formula (1), X ² is an oxygen atom or a sulfur atom, and indicates "A", and otherwise indicates "B".
In the table, the "X ⁴ " column indicates that in formula (2), X ⁴ is a sulfur atom, in which case it is indicated as "A," and otherwise it is indicated as "B."
In the table, the column "X ¹ , X ³ " is marked with "A" if, in formula ( ¹ ), X ¹ is -C(R c1 R ^c2 )-, and R ^c1 and R ^c2 do not bond to each other to form a ring, and in formula (2), X ¹ is -C(R ^c11 R ^c12 )-, and R ^c11 and R ^c12 do not bond to each other to form a ring, and marked with "B" otherwise.
In the table, the "R ^c " column indicates that, in formula (1), R ^c1 and R ^c2 are different groups, R ^c3 and R ^c4 are different groups, R ^c5 and R ^c6 are different groups, R ^c7 and R ^c8 are different groups, and in formula (2), R ^c11 and R ^c12 are different groups, R ^c13 and R ^c14 are different groups, R ^c15 and R ^c16 are different groups, and R ^c17 and R ^c18 are different groups, and indicates "A" otherwise.
In the table, the column "Formula (A-2)" indicates that A ¹ and A ² , and A ³ and A ⁴ are groups represented by formula (A-2), and indicates "A", and otherwise indicates "B".
In the table, the column "Formula (C-1), Formula (C-2)" indicates that ^A1 and ^A2 , and ^A3 and ^A4 are groups represented by formula (C-1) or formula (C-2), respectively, and "B" indicates other cases.
In the table, the "X ^c " column indicates that when X ^c1 and X ^c2 in formula (C-1) represent oxygen atoms and X ^c3 to X ^c5 in formula (C-2) represent oxygen atoms, the column is marked with "A," and when they are not marked with "B."

The results shown in Table 1 confirm that the photoelectric conversion element of the present invention has an excellent response speed when receiving green and red light, and that the response speed has a small dependency on the electric field strength. It has also been confirmed that the photoelectric conversion element of the present invention has an excellent quantum efficiency when receiving green and red light, and is also excellent in manufacturability.

By comparing Example 10 with the other Examples, it was confirmed that the effect of the present invention is more excellent when ^X2 in formula (1) represents an oxygen atom or a sulfur atom.
By comparing Example 4 with other Examples, it was confirmed that the effects of the present invention are better when ^Rc1 and ^Rc2 , ^Rc3 and ^Rc4 , ^Rc5 and ^Rc6 , and ^Rc7 and ^Rc8 are not bonded to each other to form a ring that may have a substituent, and when ^Rc1 and ^Rc2 , ^Rc3 and ^Rc4 , ^Rc5 and ^Rc6 , and ^Rc7 and ^Rc8 are not bonded to each other to form a ring that may have a substituent.
From a comparison of Examples 1 and 9 with other Examples, it was confirmed that the electric field intensity dependence of the response speed was smaller in the following case: in formula (1), ^Rc1 and ^Rc2 are different groups, ^Rc3 and ^Rc4 are different groups, ^Rc5 and ^Rc6 are different groups, ^Rc7 and ^Rc8 are different groups; and in formula (2), ^Rc11 and ^Rc12 are different groups, ^Rc13 and ^Rc14 are different groups, ^Rc15 and ^Rc16 are different groups, and ^Rc17 and ^Rc18 are different groups.
Comparison of Examples 7 and 8 with other Examples confirmed that when A ¹ and A ² , and A ³ and A ⁴ are groups represented by formula (A-2), the effects and production suitability of the present invention are superior.
From a comparison of Example 6 with other Examples, it was confirmed that when ^Xc1 and ^Xc2 in Formula (C-1) represent oxygen atoms, and ^Xc3 to ^Xc5 in Formula (C-2) represent oxygen atoms, the production suitability is superior.
Comparison of Example 5 with other Examples confirmed that when A ¹ and A ² , and A ³ and A ⁴ are groups represented by formula (C-2), the effects and production suitability of the present invention are superior.

[Test Y]
Photoelectric conversion elements Y1 to Y8 were prepared in the same manner as in [Preparation of photoelectric conversion element] of [Test X], except that compound (1) as a specific compound, an n-type organic semiconductor (fullerene (C ₆₀ )), a p-type organic semiconductor (compound (P-1)), and any one of dyes (B-1) to (B-8) were co-evaporated by a vacuum evaporation method in a predetermined ratio (specific compound:dye:p-type organic semiconductor:n-type organic semiconductor=1:1:2:2, calculated as thickness) to form a photoelectric conversion film 12 having a thickness of 300 nm.

For the obtained photoelectric conversion elements Y1 to Y8, it was confirmed that they had sufficiently low dark current according to the procedure described in the above [Test X], and then the quantum efficiency, response speed, and the electric field strength dependency of the response speed at a wavelength of 560 nm were evaluated. As a result, all of them showed evaluation results equivalent to the results of Example 1 obtained by [Test X].
Similarly, the quantum efficiency, response speed, and the electric field strength dependency of the response speed at a wavelength of 480 nm were measured, and the evaluation results were all equivalent to the results of Example 1 obtained by Test X.

In addition, when the specific compounds described in Examples 2 to 11 were used as the specific compounds, the evaluation results were equivalent to the results of Examples 2 to 11 obtained by [Test X].

From the results of Test Y, it was confirmed that the photoelectric conversion element of the present invention containing the specific compound and dye has a small electric field strength dependency of the response speed to light of wavelengths of 480 nm and 560 nm, and is also excellent in response speed.
Furthermore, the spectral sensitivity characteristics (IPCE: incident-photon-to-current conversion efficiency) of each photoelectric conversion element was measured, and it was confirmed that the photoelectric conversion element of the present invention containing the specific compound and dye has excellent quantum efficiency for light with a wavelength of 450 to 650 nm. The IPCE was measured by applying a voltage to each photoelectric conversion element so as to achieve an electric field strength of 2.0 x ¹⁰⁵ V/cm, irradiating light from the upper electrode (transparent conductive film) side, and using a constant energy quantum efficiency measurement device manufactured by Optel. The amount of irradiated light was 50 μW/ ^cm2 .

10a, 10b Photoelectric conversion element 11 Conductive film (lower electrode)
12 Photoelectric conversion film 15 Transparent conductive film (upper electrode)
16A Electron blocking film 16B Hole blocking film

Claims (24)

A photoelectric conversion element having a conductive film, a photoelectric conversion film, and a transparent conductive film in this order, wherein the photoelectric conversion film contains a compound represented by formula (1) or a compound represented by formula (2).

In formula (1), R ¹ and R ² each independently represent a hydrogen atom or a substituent.
^X1 represents -C( ^{Rc1Rc2 )} -, -O-C( ^Rc3Rc4 )-, -Si( ^Rc5Rc6 )-, or -Ge( ^Rc7Rc8 )-. Rc1, ^Rc2 , ^Rc3 , ^Rc4 , ^Rc5 , ^Rc6 , ^Rc7 , and ^Rc8 each independently represent a hydrogen atom or a substituent. ^Rc1 and ^Rc2 , ^{Rc3 and Rc4} , ^Rc5 and ^Rc6 , and ^{Rc7 and Rc8 may each} be bonded to each other to form a ring which may have ^a substituent.
^X2 represents an oxygen atom, a sulfur atom, or -NR ^N1 -, where R ^N1 represents a hydrogen atom or a substituent.
^A1 and ^A2 each independently represent a group represented by formula (A-1).
In formula (2), ^R3 and ^R4 each independently represent a hydrogen atom or a substituent.
R ^N2 represents a hydrogen atom or a substituent.
^X3 represents -C( ^{Rc11Rc12 )} -, -O-C( ^Rc13Rc14 )-, -Si( ^Rc15Rc16 )-, or -Ge( ^Rc17Rc18 )-. ^Rc11 , ^Rc12 , ^Rc13 , ^Rc14 , ^Rc15 , ^Rc16 , ^Rc17 , and ^Rc18 each independently represent a hydrogen atom or a substituent. ^Rc11 and ^Rc12 , ^{Rc13 and Rc14 , Rc15 and Rc16, and Rc17 and Rc18 may each be bonded} to each other to form a ring which may have ^a substituent.
^X4 represents a sulfur atom or -NR ^N3 -, where R ^N3 represents a hydrogen atom or a substituent.
^A3 and ^A4 each independently represent a group represented by formula (A-1).
In formula (A-1), * represents a bonding position.
^C1 represents a ring containing 2 or more carbon atoms which may have a substituent.
^W1 represents an oxygen atom, a sulfur atom, =NR ^W2 , or =CR ^W3 R ^W4 .
R ^W2 represents a hydrogen atom or a substituent. R ^W3 and R ^W4 each independently represent a cyano group, -SO ₂ R ^W5 , -COOR ^W6 or -COR ^W7 . R ^W5 to R ^W7 each independently represent an aliphatic hydrocarbon group which may have a substituent, an aromatic ring group which may have a substituent, or an aliphatic heterocyclic group which may have a substituent. The photoelectric conversion element according to claim 1 , wherein in the formula (1), X ² represents an oxygen atom or a sulfur atom. The photoelectric conversion element according to claim 1 , wherein in the formula (2), X ⁴ represents a sulfur atom. In the formula (1), X ¹ represents —C(R ^c1 R ^c2 )—;
^{2. The photoelectric conversion element according to claim 1, wherein in said formula (2), X3 represents -C(Rc11Rc12 ) -} .
R ^c1 and R ^c2 do not bond to each other to form a ring which may have a substituent, and R ^c11 and R ^c12 do not bond to each other to form a ring which may have a substituent. In the formula (1), R ^c1 and R ^c2 are different groups, R ^c3 and R ^c4 are different groups, R ^c5 and R ^c6 are different groups, and R ^c7 and R ^c8 are different groups;
2. The photoelectric conversion element according to claim 1, wherein, in the formula (2), ^Rc11 and ^Rc12 are different groups, ^Rc13 and ^Rc14 are different groups, ^Rc15 and ^Rc16 are different groups, and ^Rc17 and ^Rc18 are different groups. 6. The photoelectric conversion element according to claim 1, wherein the group represented by formula (A-1) is a group represented by formula (A-2).

In formula (A-2), * represents a bonding position.
^C2 represents a ring containing 3 or more carbon atoms which may have a substituent.
^W2 and ^W3 each independently represent an oxygen atom or a sulfur atom. 7. The photoelectric conversion element according to claim 6, wherein the group represented by formula (A-2) is a group represented by formula (C-1) or formula (C-2).

In formula (C-1), * represents a bonding position.
^Xc1 and ^Xc2 each independently represent an oxygen atom or a sulfur atom.
^C3 represents an aromatic ring which may have a substituent.
In formula (C-2), * represents a bonding position.
X ^c3 to X ^c5 each independently represent an oxygen atom or a sulfur atom.
R ^c1 and R ^c2 each independently represent a hydrogen atom or a substituent. In the formula (C-1), ^Xc1 and ^Xc2 each represent an oxygen atom;
8. The photoelectric conversion element according to claim 7, wherein in formula (C-2), ^Xc3 and ^Xc4 represent oxygen atoms. the photoelectric conversion film further contains an n-type organic semiconductor,
The photoelectric conversion element according to any one of claims 1 to 5, wherein the photoelectric conversion film has a bulk heterostructure formed in a state in which the compound represented by formula (1) and the n-type organic semiconductor are mixed. The photoelectric conversion element according to claim 9, wherein the n-type organic semiconductor contains fullerenes selected from the group consisting of fullerenes and derivatives thereof. The photoelectric conversion element according to any one of claims 1 to 5, wherein the photoelectric conversion film further contains a p-type organic semiconductor. The photoelectric conversion element according to any one of claims 1 to 5, wherein the photoelectric conversion film further contains a dye. The photoelectric conversion element according to any one of claims 1 to 5, which has one or more intermediate layers between the conductive film and the transparent conductive film in addition to the photoelectric conversion film. An imaging device having a photoelectric conversion element according to any one of claims 1 to 5. An optical sensor having a photoelectric conversion element according to any one of claims 1 to 5. A method for manufacturing an imaging element, comprising the step of manufacturing a photoelectric conversion element according to any one of claims 1 to 5. A compound represented by formula (1) or formula (2).

In formula (1), R ¹ and R ² each independently represent a hydrogen atom or a substituent.
^X1 represents -C( ^{Rc1Rc2 )} -, -O-C( ^Rc3Rc4 )-, -Si( ^Rc5Rc6 )-, or -Ge( ^Rc7Rc8 )-. Rc1, ^Rc2 , ^Rc3 , ^Rc4 , ^Rc5 , ^Rc6 , ^Rc7 , and ^Rc8 each independently represent a hydrogen atom or a substituent. ^Rc1 and ^Rc2 , ^{Rc3 and Rc4} , ^Rc5 and ^Rc6 , and ^{Rc7 and Rc8 may each} be bonded to each other to form a ring which may have ^a substituent.
^X2 represents an oxygen atom, a sulfur atom, or -NR ^N1 -, where R ^N1 represents a hydrogen atom or a substituent.
^A1 and ^A2 each independently represent a group represented by formula (A-1).
In formula (2), ^R3 and ^R4 each independently represent a hydrogen atom or a substituent.
R ^N2 represents a hydrogen atom or a substituent.
^X3 represents -C( ^{Rc11Rc12 )} -, -O-C( ^Rc13Rc14 )-, -Si( ^Rc15Rc16 )-, or -Ge( ^Rc17Rc18 )-. ^Rc11 , ^Rc12 , ^Rc13 , ^Rc14 , ^Rc15 , ^Rc16 , ^Rc17 , and ^Rc18 each independently represent a hydrogen atom or a substituent. ^Rc11 and ^Rc12 , ^{Rc13 and Rc14 , Rc15 and Rc16, and Rc17 and Rc18 may each be bonded} to each other to form a ring which may have ^a substituent.
^X4 represents a sulfur atom or -NR ^N3 -, where R ^N3 represents a hydrogen atom or a substituent.
^A3 and ^A4 each independently represent a group represented by formula (A-1).
In formula (A-1), * represents a bonding position.
^C1 represents a ring containing 2 or more carbon atoms which may have a substituent.
^W1 represents an oxygen atom, a sulfur atom, =NR ^W2 or =CR ^W3 R ^W4 .
R ^W2 represents a hydrogen atom or a substituent. R ^W3 and R ^W4 each independently represent a cyano group, -SO ₂ R ^W5 , -COOR ^W6 or -COR ^W7 . R ^W5 to R ^W7 each independently represent an aliphatic hydrocarbon group which may have a substituent, an aromatic ring group which may have a substituent, or an aliphatic heterocyclic group which may have a substituent. The compound according to claim 17 , wherein in the formula (1), X ² represents an oxygen atom or a sulfur atom. The compound according to claim 17, wherein in the formula (2), X ⁴ represents a sulfur atom. In the formula (1), X ¹ represents —C(R ^c1 R ^c2 )—;
The compound according to claim 17, wherein in said formula (2), X ³ represents -C(R ^c11 R ^c12 )-.
R ^c1 and R ^c2 do not bond to each other to form a ring which may have a substituent, and R ^c11 and R ^c12 do not bond to each other to form a ring which may have a substituent. In the formula (1), R ^c1 and R ^c2 are different groups, R ^c3 and R ^c4 are different groups, R ^c5 and R ^c6 are different groups, and R ^c7 and R ^c8 are different groups;
In the formula (2), R ^c11 and R ^c12 are different groups, R ^c13 and R ^c14 are different groups, R ^c15 and R ^c16 are different groups, and R ^c17 and R ^c18 are different groups. The compound according to any one of claims 17 to 21, wherein the group represented by formula (A-1) is a group represented by formula (A-2).

In formula (A-2), * represents a bonding position.
^C2 represents a ring containing 3 or more carbon atoms which may have a substituent.
^W2 and ^W3 each independently represent an oxygen atom or a sulfur atom. The compound according to claim 22, wherein the group represented by formula (A-2) is a group represented by formula (C-1) or formula (C-2).

In formula (C-1), * represents a bonding position.
^Xc1 and ^Xc2 each independently represent an oxygen atom or a sulfur atom.
^C3 represents an aromatic ring which may have a substituent.
In formula (C-2), * represents a bonding position.
X ^c3 to X ^c5 each independently represent an oxygen atom or a sulfur atom.
R ^c1 and R ^c2 each independently represent a hydrogen atom or a substituent. In the formula (C-1), ^Xc1 and ^Xc2 each represent an oxygen atom;
The compound according to claim 23, wherein in formula (C-2), X ^c3 and X ^c4 represent an oxygen atom.