Compound, organic thin film, photoelectric conversion element, imaging element, optical sensor, and solid state imaging device

Abstract

Provided is the compound represented by formula (I) (in the formula, X1 is an oxygen atom or NR3, X2 is a nitrogen atom or CR4, X3 is a nitrogen atom or CR5, n is an integer from 0 to 3, R1 to R5 are each independently a hydrogen atom, a halogen atom, a cyano group, a straight chain, a branched or cyclic alkyl group, or the like, and R6 and R7 are each independently a hydrogen atom, a halogen atom other than a fluorine atom, a cyano group, a straight chain, a branched or cyclic alkyl group, or the like).

Description

Compound, organic thin film, photoelectric conversion element, imaging element, optical sensor and solid-state imaging device

[0001] The present disclosure relates to a compound, an organic thin film, a photoelectric conversion element, an imaging element, an optical sensor, and a solid-state imaging device.

[0002] Conventionally, techniques for photoelectrically converting visible light into an electrical signal have been known and are used, for example, in image sensors. Such image sensors are included in solid-state image sensors such as charge-coupled device (CCD) image sensors and complementary metal oxide semiconductor (CMOS) image sensors. In recent years, pixel sizes in solid-state image sensors have been reduced, and organic photoelectric conversion films have been developed to address this trend. For example, Patent Documents 1 and 2 disclose organic photoelectric conversion films composed of subphthalocyanine and imides.

[0003] Furthermore, solid-state imaging devices are required to achieve both high spectral selectivity and a high S / N ratio. Therefore, solid-state imaging devices are desired to have high external quantum efficiency (EQE) and low dark current characteristics. To achieve both, a known technique involves disposing an electron transport layer and a hole blocking layer, and / or a hole transport layer and an electron blocking layer, between a photoelectric conversion unit and an electrode unit. Here, electron transport layers, hole blocking layers, and electron blocking layers, which are widely used in the field of organic electronic devices, are disposed at the interface between an electrode or conductive film and other films in the films that constitute the device. These layers serve to control the reverse movement of holes or electrons, respectively, and to adjust the leakage of unnecessary holes or electrons. Patent Document 3, for example, discloses an example of the use of 1,4,5,8-naphthalenetetracarboxylic dianhydride (NTCDA) as a material for such layers.

[0004] Japanese Patent Application Laid-Open No. 2018-32754 Japanese Patent Application Laid-Open No. 2018-512423 Japanese Patent Application Laid-Open No. 2014-506736

[0005] However, conventional hole-blocking layers and electron-blocking layers, including those disclosed in Patent Document 3, have room for further improvement in terms of suppressing leakage current in the dark and providing high wavelength selectivity.

[0006] The present invention aims to provide a compound and a photoelectric conversion element material that can suppress leakage current in the dark and are particularly useful for photoelectric conversion elements, as well as an organic thin film, a photoelectric conversion element, an imaging element, a photosensor, and a solid-state imaging device that each contain the compound.

[0007] The present invention is as follows: [1] A compound of the following formula (I): (X is an oxygen atom or NR ３ and X ２ is a nitrogen atom or CR ４ and X ３ is a nitrogen atom or CR ５ n is an integer of 0 to 3, １ , R ２ , R ３ , R ４ and R ５ are each independently selected from the group consisting of a hydrogen atom, a halogen atom, a hydroxy group, a thiol group, an amino group, a cyano group, a carboxy group, a nitro group, and an optionally substituted linear, branched, or cyclic alkyl group, a thioalkyl group, a thioaryl group, an arylsulfonyl group, an aryloxy group, an alkylsulfonyl group, an alkylamino group, an arylamino group, an alkoxy group, an acylamino group, an acyloxy group, an aryl group, a carboxamido group, a carboalkoxy group, a carboaryloxy group, an acyl group, and a monovalent heterocyclic group; １ , R ２ , R ４ and R ５ may be part of a fused ring, and the fused ring may contain one or more atoms other than carbon atoms. excluding compounds represented by the formula (2). ３ is represented by the following formula (IV): (R ６ , R７ , R ８ , R ９ and R １０ are each independently selected from the group consisting of a hydrogen atom, a halogen atom, a hydroxy group, a thiol group, an amino group, a cyano group, a carboxy group, a nitro group, and an optionally substituted linear, branched, or cyclic alkyl group, a thioalkyl group, a thioaryl group, an arylsulfonyl group, an aryloxy group, an alkylsulfonyl group, an alkylamino group, an arylamino group, an alkoxy group, an acylamino group, an acyloxy group, an aryl group, a carboxamido group, a carboalkoxy group, a carboaryloxy group, an acyl group, and a monovalent heterocyclic group; ６ , R ７ , R ８ , R ９ and R 1０ may be a part of a fused ring, and the fused ring may contain one or more atoms other than carbon atoms.) [3] The compound according to [1] or [2], wherein the energy level of the lowest unoccupied molecular orbital obtained by density functional theory is -6.00 eV or more and -3.50 eV or less. [4] The compound according to any one of [1] to [3], which is a material for a photoelectric conversion element. [5] The compound according to the following formula (I): (X is an oxygen atom or NR ３ and X ２ is a nitrogen atom or CR ４ and X ３ is a nitrogen atom or CR ５ n is an integer of 0 to 3, １ , R ２ , R ３ , R ４ and R ５are each independently selected from the group consisting of a hydrogen atom, a halogen atom, a hydroxy group, a thiol group, an amino group, a cyano group, a carboxy group, a nitro group, and an optionally substituted linear, branched, or cyclic alkyl group, a thioalkyl group, a thioaryl group, an arylsulfonyl group, an aryloxy group, an alkylsulfonyl group, an alkylamino group, an arylamino group, an alkoxy group, an acylamino group, an acyloxy group, an aryl group, a carboxamido group, a carboalkoxy group, a carboaryloxy group, an acyl group, and a monovalent heterocyclic group; １ , R ２ , R ４ and R ５may be part of a fused ring, and the fused ring may contain one or more atoms other than carbon atoms. [6] A photoelectric conversion element comprising a first electrode film, a second electrode film, and a photoelectric conversion film located between the first electrode film and the second electrode film, wherein the photoelectric conversion film comprises the material for a photoelectric conversion element according to [4]. [7] A photoelectric conversion element comprising a first electrode film, a second electrode film, and a photoelectric conversion film located between the first electrode film and the second electrode film, wherein the photoelectric conversion film comprises the organic thin film according to [5]. [8] The photoelectric conversion element according to [6] or [7], wherein the photoelectric conversion film comprises a photoelectric conversion layer and an auxiliary layer, and the auxiliary layer consists of only the organic thin film or consists of a plurality of films including the organic thin film. [9] A photoelectric conversion element comprising a first electrode film, a second electrode film, and a photoelectric conversion film located between the first electrode film and the second electrode film, wherein the photoelectric conversion film comprises a photoelectric conversion layer and two auxiliary layers located between the photoelectric conversion layer and the second electrode film, and one of the two auxiliary layers closest to the second electrode film includes the organic thin film described in [5].

[10] An imaging element comprising the photoelectric conversion element described in any of [6] to [9].

[11] The imaging element described in

[10] , which is formed by stacking two or more of the photoelectric conversion elements.

[12] An imaging element comprising a plurality of the photoelectric conversion elements described in [6] or [9] arranged in an array.

[13] An optical sensor comprising the imaging element described in any of

[10] to

[12] .

[14] A solid-state imaging device comprising the imaging element described in any of

[10] to

[12] .

[0008] According to the present invention, it is possible to provide a compound and a photoelectric conversion element material that can suppress leakage current in the dark and are particularly useful for photoelectric conversion elements, as well as an organic thin film, a photoelectric conversion element, an imaging element, a photosensor, and a solid-state imaging device that each contain the compound.

[0009] 1 is a schematic cross-sectional view partially showing an example of the photoelectric conversion element of the present invention. 2 is a schematic cross-sectional view partially showing another example of the photoelectric conversion element of the present invention.

[0010] Hereinafter, a detailed description will be given of an embodiment of the present invention (hereinafter simply referred to as "the present embodiment") with reference to the drawings as necessary, but the present invention is not limited to the present embodiment. The present invention can be modified in various ways without departing from the gist of the present invention. In the drawings, the same elements are designated by the same reference numerals, and redundant explanations will be omitted. Furthermore, positional relationships such as up, down, left, and right are based on the positional relationships shown in the drawings unless otherwise specified. Furthermore, the dimensional ratios of the drawings are not limited to those shown.

[0011] In this specification, halogen atoms include fluorine atoms (F), chlorine atoms (Cl), bromine atoms (Br) and iodine atoms (I).

[0012] In this specification, the straight-chain alkyl group may be a straight-chain alkyl group having 1 to 12 carbon atoms in the alkyl group, and examples thereof include a methyl group (Me), an ethyl group (Et), an n-propyl group (n-Pr), an n-butyl group (n-Bu), an n-pentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, an n-nonyl group, an n-decyl group, and an n-dodecyl group.

[0013] In this specification, the branched alkyl group may be a branched alkyl group having 1 to 12 carbon atoms in the alkyl group, and examples thereof include an isopropyl group (i-Pr), a sec-butyl group (s-Bu), a tert-butyl group (t-Bu), an isopentyl group, a sec-pentyl group, a 3-pentyl group, a neopentyl group, an isohexyl group, an isooctyl group, an isononyl group, an isodecyl group, and an isododecyl group. Furthermore, the linear or branched alkyl group may have a substituent. Examples of the substituent include a halogen atom such as a fluorine atom, a monovalent group having an aromatic ring such as a benzyl group, a naphthyl group, and a phenoxy group, an alkoxy group, a monovalent group having a heteroatom such as an aminoalkyl group and a thioalkyl group, a monovalent group having a heterocyclic ring such as a pyridyl group, a hydroxy group, a carboxyl group, an amino group, and a thiol group.

[0014] In this specification, the cyclic alkyl group may be a cyclic alkyl group having 3 to 10 carbon atoms in the alkyl group, and examples thereof include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group. Furthermore, the cyclic alkyl group may have heteroatoms such as a nitrogen atom, an oxygen atom, and a sulfur atom in the ring. Examples of such cyclic alkyl groups include a pyrrolidinyl group, an oxazolidinyl group, a pyrazolidinyl group, a thiazolidinyl group, an imidazolidinyl group, a dioxofuranyl group, a tetrahydrofuranyl group, a tetrahydrothiophenyl group, a piperazinyl group, a dioxanyl group, and a morpholinyl group. Furthermore, a monovalent group such as a hydroxy group, a carboxyl group, an amino group, or a thiol group may be bonded to the cyclic alkyl group.

[0015] In this specification, the thioalkyl group (-SR; hereinafter, R represents an alkyl group) and the thioaryl group (-SAr; hereinafter, Ar represents an aryl group) may be a thioalkyl group in which the alkyl group has 1 to 12 carbon atoms, and a thioaryl group in which the aryl group has 6 to 16 carbon atoms. The thioalkyl group and the thioaryl group may further have a substituent such as an amino group, a hydroxy group, a halogen atom, an alkoxy group, or a thioalkyl group. Examples of such thioalkyl group and thioaryl group include a methylthio group, an ethylthio group, a phenylthio group, a toluylthio group, an aminophenylthio group, a hydroxyphenylthio group, a fluorophenylthio group, a dimethylphenylthio group, and a methylthiophenylthio group.

[0016] In this specification, the arylsulfonyl group (—SO—Ar) may be an arylsulfonyl group having 6 to 16 carbon atoms in the aryl group, and examples thereof include a phenylsulfonyl group, a toluenesulfonyl group, a dimethylbenzenesulfonyl group, a mesitylenesulfonyl group, an octylbenzenesulfonyl group, and a naphthalenesulfonyl group.

[0017] In this specification, the aryloxy group (-O-Ar) may be an aryloxy group having 6 to 16 carbon atoms in the aryl group. The aryloxy group may further have a substituent such as a cyano group, a halogen atom such as a fluorine atom, a hydroxy group, an alkoxy group such as a methoxy group, an amino group, an alkylamino group, a thiol group, or an aryloxy group. Examples of such aryloxy groups include a phenoxy group, a cyanophenoxy group, a methylcyanophenoxy group, a dimethylcyanophenoxy group, a fluorocyanophenoxy group, a dicyanophenoxy group, a methoxycyanophenoxy group, a tricyanophenoxy group, a cyanonaphthoxy group, a dicyanonaphthoxy group, a 2-methylphenoxy group, a 3-methylphenoxy group, a 4-methylphenoxy group, a fluoromethylphenoxy group, a dimethylphenoxy group, a 3-hydroxyphenoxy group, Examples of such groups include a fluoro-3-hydroxyphenoxy group, a 2-hydroxyphenoxy group, a fluoro-2-hydroxyphenoxy group, a methoxyphenoxy group, an ethoxyphenoxy group, a fluorophenoxy group, a perfluorophenoxy group, a dimethoxyphenoxy group, an aminophenoxy group, an N,N-dimethylaminophenoxy group, a thiophenoxy group, a (trifluoromethyl)phenoxy group, a naphthoxy group, a methoxynaphthoxy group, a fluoronaphthoxy group, and a phenoxyphenoxy group.

[0018] In this specification, the alkylsulfonyl group (—SO—R) may be an alkylsulfonyl group in which the alkyl group has 1 to 12 carbon atoms, and examples thereof include a mesyl group, an ethylsulfonyl group, and an n-butylsulfonyl group.

[0019] In this specification, the alkylamino group (here, the alkylamino group is —NHR or —NR, and the two Rs may be the same or different) may be an alkylamino group in which the alkyl group has 1 to 12 carbon atoms, and examples thereof include a methylamino group, an ethylamino group, an n-propylamino group, an n-butylamino group, an n-pentylamino group, an n-hexylamino group, an n-heptylamino group, an n-octylamino group, an n-nonylamino group, an n-decylamino group, an n-dodecylamino group, an isopropylamino group, a sec-butylamino group, a tert-butylamino group, an isopentylamino group, a sec-pentylamino group, a 3-pentylamino group, a neopentylamino group, an isohexylamino group, an isoheptylamino group, an isooctylamino group, an isononylamino group, an isodecylamino group, an isododecylamino group, a dimethylamino group, a diethylamino group, a diisopropylamino group, and an isopropylethylamino group.

[0020] In this specification, the arylamino group (here, the arylamino group is -NHAr or -NAr2, and the two Ars may be the same or different) may be an arylamino group having 6 to 16 carbon atoms, and examples thereof include an anilyl group, a toluidinyl group, a dimethylanilyl group, an isopropylanilyl group, a t-butylanilyl group, a fluoroanilyl group, a trifluoromethylanilyl group, a bis(trifluoromethyl)anilyl group, a pyridylamino group, a methylpyridylamino group, a fluoropyridylamino group, a pyrimidylamino group, and a biphenylamino group.

[0021] In this specification, the alkoxy group (—OR) may be an alkoxy group having 1 to 12 carbon atoms, and examples thereof include a methoxy group, an ethoxy group, an n-propoxy group, an n-butyloxy group, an n-pentoxy group, an n-hexoxy group, an n-heptoxy group, an n-octoxy group, an n-nonoxy group, an n-decoxy group, an n-dodecoxy group, an isopropoxy group, a sec-butyloxy group, a tert-butyloxy group, an isopentoxy group, a sec-pentoxy group, a 3-pentoxy group, a neopentoxy group, an isohexoxy group, an isooctoxy group, an isonoxy group, an isodecoxy group, and an isododecoxy group.

[0022] In this specification, the acylamino group (-NH-COR or -NH-COAr) may have 1 to 12 carbon atoms in the alkyl group or 6 to 16 carbon atoms in the aryl group, and may have a substituent such as a halogen atom such as a fluorine atom, an alkoxy group, or a cyano group. Examples of such acylamino groups include an acetylamino group, a propionylamino group, a benzoylamino group, a methylbenzoylamino group, a dimethylbenzoylamino group, a methoxybenzoylamino group, a cyanobenzoylamino group, and a bis(trifluoromethyl)benzoylamino group.

[0023] In this specification, the acyloxy group (-O-COR or -O-COAr) may have 1 to 12 carbon atoms in the alkyl group or 6 to 16 carbon atoms in the aryl group. The acyloxy group may further have a substituent such as a halogen atom such as a fluorine atom, a cyano group, or an optionally substituted alkyl group, and may have a heteroatom such as a nitrogen atom in the aromatic ring. Examples of such acyloxy groups include a benzoyloxy group, a toluoyloxy group, a dimethylbenzoyloxy group, a cyanobenzoyloxy group, a fluorobenzoyloxy group, a bis(trifluoromethyl)benzoyloxy group, a pyridinecarboxy group, and a methylpyridinecarboxy group.

[0024] In this specification, the aryl group (-Ar) may be an aryl group having 6 to 16 carbon atoms. The aryl group may further have a substituent such as an amino group, a hydroxy group, a thiol group, a halogen atom such as a fluorine atom, a nitro group, a cyano group, or an optionally substituted alkyl group, and may have a heteroatom such as a nitrogen atom in the aromatic ring. Examples of such aryl groups include a phenyl group, a methylphenyl group, an ethylphenyl group, a dimethylphenyl group, a trimethylphenyl group, a methoxyphenyl group, a dimethoxyphenyl group, a trimethoxyphenyl group, a methoxymethylphenyl group, an aminophenyl group, a diaminophenyl group, an aminomethylphenyl group, a hydroxyphenyl group, a dihydroxyphenyl group, a hydroxymethylphenyl group, a hydroxyethylphenyl group, a thiophenyl group, a methylthiophenyl group, a dithiophenyl group, a fluorophenyl group, a fluoromethylphenyl group, a trifluoromethylphenyl group, a perfluorophenyl group, a fluoro(trifluoromethyl)phenyl group, a bis(trifluoromethyl)phenyl group, a cyanophenyl group, a methylcyanophenyl group, a dimethylcyanophenyl group, a dicyanophenyl group, a methoxycyanophenyl group, a tricyanophenyl group, and a dicyanophenyl group. , a methylcyanopyridyl group, a (trifluoromethyl)cyanopyridyl group, a dimethylcyanopyridyl group, a dicyanopyridyl group, a methoxycyanopyridyl group, a tricyanopyridyl group, a cyanopyridyl group, a naphthyl group, a nitrophenyl group, a dinitrophenyl group, a nitrofluorophenyl group, a methylnaphthyl group, an ethylnaphthyl group, a dimethylnaphthyl group, a trimethylnaphthyl group, a methoxynaphthyl group, a dimethoxynaphthyl group, a trimethoxynaphthyl group, an aminonaphthyl group, a diaminonaphthyl group, an aminomethylnaphthyl group, a hydroxynaphthyl group, a dihydroxynaphthyl group, a hydroxymethylnaphthyl group, a hydroxyethylnaphthyl group, a thionaphthyl group, a methylthionaphthyl group, a dithionaphthyl group, a fluoronaphthyl group, a trifluoromethylnaphthyl group, a perfluoronaphthyl group, a di(trifluoromethyl)naphthyl group, a biphenyl group, and a cyanobiphenyl group.

[0025] In this specification, the carboxyamide group (here, the carboxyamide group is -CO-NH, -CO-NHR, or -CONR, where two Rs may be the same or different, or -CONHAr or -CONAr, where two Ars may be the same or different) may be a carboxyamide group in which the alkyl group has 1 to 12 carbon atoms or the aryl group has 6 to 16 carbon atoms, and examples thereof include a dimethylcarboxyamide group and a diphenylcarboxyamide group.

[0026] In this specification, the carboalkoxy group and carboaryloxy group (-COOR or -COOAr) may be a carboalkoxy group or a carboaryloxy group having 1 to 12 carbon atoms in the alkyl group or 6 to 16 carbon atoms in the aryl group, and examples thereof include a carbomethoxy group and a carbophenoxy group.

[0027] In this specification, the monovalent heterocyclic group may be a monovalent heterocyclic group having 3 to 14 carbon atoms, and examples thereof include a furanyl group, a thienyl group, a pyrrolyl group, a pyrazolyl group, an imidazolyl group, a triazolyl group, an oxazolyl group, a dioxazolyl group, an isoxazolyl group, an oxadiazolyl group, a thiazolyl group, an isothiazolyl group, a thiadiazolyl group, a triazolyl group, an indolyl group, an indolinyl group, an indolizinyl group, an indazolinyl group, an indoleninyl group, a benzofuranyl group, a benzothienyl group, a carbazolyl group, a dibenzofuranyl group, a Examples of such groups include aranyl group, dibenzothienyl group, pyridinyl group, diazinyl group, oxazinyl group, thiazinyl group, dioxinyl group, dithienyl group, triazinyl group, pyrimidinyl group, pyrazinyl group, pyridazinyl group, quinolinyl group, isoquinolinyl group, cinnolinyl group, phthalazinyl group, quinazolinyl group, naphthyridinyl group, purinyl group, pteridinyl group, acridinyl group, phenanthridinyl group, phenanthrolinyl group, xanthenyl group, phenoxazinyl group, thianthrenyl group, morpholinyl group, and phenazinyl group.

[0028] (Compound (I)) The compound of this embodiment is represented by the following formula (I): (Hereinafter, this compound will also be referred to as "compound (I)"), where X is an oxygen atom or NR ３ and X ２ is a nitrogen atom or CR ４ and X ３ is a nitrogen atom or CR ５ n is an integer of 0 to 3, and R １ , R ２ , R ３ , R ４ and R ５ are each independently selected from the group consisting of a hydrogen atom, a halogen atom, a hydroxy group, a thiol group, an amino group, a cyano group, a carboxy group, a nitro group, and an optionally substituted linear, branched, or cyclic alkyl group, a thioalkyl group, a thioaryl group, an arylsulfonyl group, an aryloxy group, an alkylsulfonyl group, an alkylamino group, an arylamino group, an alkoxy group, an acylamino group, an acyloxy group, an aryl group, a carboxamido group, a carboalkoxy group, a carboaryloxy group, an acyl group, and a monovalent heterocyclic group; １ , R ２ , R ４ and R ５ may be part of a fused ring, and the fused ring may contain one or more atoms other than carbon atoms. However, the compound of this embodiment is represented by the following formula (II) and formula (III): Excluding compounds represented by the formula:

[0029] Such compound (I) can suppress leakage current in the dark and exhibits excellent properties, particularly as a material for a photoelectric conversion element. The reason for this is unclear, but the present inventors believe it to be as follows. However, the reason is not limited to the following. That is, by having a structure with an extended π-conjugated system, the energy level of the lowest unoccupied molecular orbital of compound (I) is lowered, and leakage current in the dark can be suppressed.

[0030] Compound (I) of this embodiment, when n is 0, 1, 2, or 3, is represented by the following formulas (Ia), (Ib), (Ic), and (Id), respectively.

[0031] In compound (I) of this embodiment, X １ From the viewpoint of more effectively and reliably achieving the effects of the present invention, ３ It is preferable that:

[0032] In compound (I) of this embodiment, R ３ From the viewpoint of more effectively and reliably exhibiting the effects of the present invention, is preferably selected from the group consisting of a hydrogen atom, a halogen atom, a hydroxy group, a thiol group, an amino group, a cyano group, a carboxy group, a nitro group, and an optionally substituted linear, branched, or cyclic alkyl group, a thioalkyl group, a thioaryl group, an arylsulfonyl group, an aryloxy group, an alkylsulfonyl group, an alkylamino group, an arylamino group, an alkoxy group, an acylamino group, an acyloxy group, an aryl group, a carboxamido group, a carboalkoxy group, a carboaryloxy group, an acyl group, and a monovalent heterocyclic group; is more preferably selected from the group consisting of an optionally substituted linear, branched, or cyclic alkyl group and an aryl group; and is particularly preferably selected from the group consisting of a hydrogen atom, a halogen atom, a nitro group, a cyano group, and an alkyl group and aryl group substituted with a halogen atom.

[0033] R ３ is an optionally substituted aryl group, R ３ is represented by the following formula (IV): Preferably, R is a group represented by the formula: ６ , R ７ , R ８ , R ９ and R １０ are each independently selected from the group consisting of a hydrogen atom, a halogen atom, a hydroxy group, a thiol group, an amino group, a cyano group, a carboxy group, a nitro group, and an optionally substituted linear, branched, or cyclic alkyl group, a thioalkyl group, a thioaryl group, an arylsulfonyl group, an aryloxy group, an alkylsulfonyl group, an alkylamino group, an arylamino group, an alkoxy group, an acylamino group, an acyloxy group, an aryl group, a carboxamido group, a carboalkoxy group, a carboaryloxy group, an acyl group, and a monovalent heterocyclic group;６ , R ７ , R ８ , R ９ and R 1０ may be part of a fused ring, and said fused ring may contain one or more atoms other than carbon atoms.

[0034] In formula (IV), R ６ , R ７ , R ８ , R ９ and R １０ From the viewpoint of more effectively and reliably exhibiting the effects of the present invention, it is preferable that each of the groups be independently selected from the group consisting of a hydrogen atom, a halogen atom, a nitro group, a cyano group, and an optionally substituted linear, branched, or cyclic alkyl group, and it is more preferable that each of the groups be selected from the group consisting of a hydrogen atom, a halogen atom, a nitro group, a cyano group, and an alkyl group substituted with a halogen atom.

[0035] In formula (IV), R ６ , R ７ , R ８ , R ９ and R １０ may be the same or different. From the viewpoint of more effectively and reliably achieving the effects of the present invention, R ６ , R ７ , R ８ , R ９ and R １０ Preferably, at least two selected from R ６ , R ７ , R ８ , R ９ and R １０ More preferably, at least three selected from R ６ , R ７ , R ８ , R ９ and R １０ It is particularly preferred that at least five selected from are identical.

[0036] In formula (IV), R ６ , R ７ , R ８ , R ９ and R １０Preferably, at least one selected from is not a hydrogen atom, and R ６ , R ７ , R ８ , R ９ and R １０ It is more preferable that at least two selected from R ６ is preferably not a hydrogen atom, and R ６ and R ７ is preferably not a hydrogen atom, and R ６ and R ９ is preferably not a hydrogen atom, or R ７ and R ８ is preferably not a hydrogen atom.

[0037] In the following, in compound (IV), R ６ , R ７ , R ８ , R ９ and R １０ The following shows a preferred combination:

[0038]

[0039]

[0040]

[0041]

[0042]

[0043]

[0044]

[0045]

[0046]

[0047]

[0048] In compound (I) of this embodiment, X ２ and X ３ may be the same or different, but are preferably the same. ２ and X ３ are CR４ and CR ５ It is preferable that:

[0049] In compound (I) of this embodiment, R ４ and R ５ are not particularly limited, but from the viewpoint of more effectively and reliably achieving the effects of the present invention, each independently is preferably selected from the group consisting of a hydrogen atom, a halogen atom, a hydroxy group, a thiol group, an amino group, a cyano group, a carboxy group, a nitro group, and optionally substituted linear, branched, or cyclic alkyl groups, thioalkyl groups, thioaryl groups, arylsulfonyl groups, aryloxy groups, alkylsulfonyl groups, alkylamino groups, arylamino groups, alkoxy groups, acylamino groups, acyloxy groups, aryl groups, carboxyamide groups, carboalkoxy groups, carboaryloxy groups, acyl groups, and monovalent heterocyclic groups, more preferably selected from the group consisting of a hydrogen atom, a halogen atom, a nitro group, a cyano group, and optionally substituted linear, branched, or cyclic alkyl groups, particularly preferably selected from the group consisting of a hydrogen atom, a halogen atom, a nitro group, a cyano group, and an alkyl group substituted with a halogen atom, and extremely preferably a hydrogen atom. When compound (I) has the above structure, leakage current in the dark can be further suppressed.

[0050] In compound (I) of this embodiment, X ２ and X ３ However, each ４ and CR ５ If R ４ and R ５ may be the same or different. From the viewpoint of more effectively and reliably achieving the effects of the present invention, R ４ and R ５ are preferably the same.

[0051] In the compound (I) of this embodiment, R and R are, from the viewpoint of more effectively and reliably exerting the effects of the present invention, each independently a hydrogen atom, a halogen atom, a hydroxy group, a thiol group, an amino group, a cyano group, a carboxy group, a nitro group, and optionally substituted, straight-chain, branched or cyclic alkyl groups, thioalkyl groups, thioaryl groups, arylsulfonyl groups, aryloxy groups, alkylsulfonyl groups, alkylamino groups, arylamino groups, alkoxy groups, acylamino groups, acyloxy groups, aryl groups, carboxyamide groups, carboalkoxy groups, carboaryloxy groups, acyl groups, and monovalent heterocyclic groups. It is more preferred to be selected from the group consisting of a hydrogen atom, a halogen atom, a nitro group, a cyano group, and optionally substituted, straight-chain, branched or cyclic alkyl groups. It is particularly preferred to be selected from the group consisting of a hydrogen atom, a halogen atom, a nitro group, a cyano group, and an alkyl group substituted with a halogen atom. It is extremely preferred to be an alkyl group substituted with a halogen atom (for example, a perfluoroalkyl group) or a hydrogen atom. Moreover, a trifluoromethyl group is preferred as the perfluoroalkyl group. When the compound (I) has the above-described structure, leakage current in the dark can be further suppressed.

[0052] In compound (I) of this embodiment, R and R may be the same or different. From the viewpoint of more effectively and reliably achieving the effects of the present invention, it is preferable that R and R are the same.

[0053] In compound (I) of this embodiment, n is preferably an integer of 0 or more and 2 or less, more preferably 0 or 1, and even more preferably 1.

[0054] Preferred combinations of R1, R2, R4, and R5 in compound (I) are shown below.

[0055]

[0056]

[0057]

[0058]

[0059]

[0060]

[0061]

[0062]

[0063] Specific examples of Compound (I) are shown below, but Compound (I) is not limited to these.

[0064]

[0065]

[0066]

[0067] The energy level of the lowest unoccupied molecular orbital (LUMO) of compound (I) of this embodiment obtained by density functional theory is preferably −6.00 eV or more and −3.50 eV or less, and more preferably −5.50 eV or more and −3.65 eV or less, from the viewpoint of more effectively and reliably achieving the effects of the present invention. Compound (I) of this embodiment can be optimized in structure by molecular simulation using density functional theory (e.g., molecular simulation using Gaussian, a quantum chemistry calculation program manufactured by Gaussian), to determine the energy level of the lowest unoccupied molecular orbital of compound (I). Furthermore, the energy level of the lowest unoccupied molecular orbital of compound (I) obtained by density functional theory can be determined by the following equation: １ ~X ３ may be adjusted by changing

[0068] The molecular weight of compound (I) of this embodiment is preferably 350 or more, more preferably 370 or more, and even more preferably 390 or more. When the molecular weight is 350 or more, changes in physical properties due to thermal motion of molecules that may occur during heating operations in the production process of an organic thin film using compound (I) or in a high-temperature usage environment can be more effectively suppressed. Furthermore, particularly when compound (I) is formed by vacuum deposition, the molecular weight of compound (I) is preferably 1000 or less, more preferably 950 or less, and even more preferably 900 or less. When the molecular weight is 1000 or less, the thermal energy required for sublimation when forming an organic thin film of compound (I) by vacuum deposition can be further reduced. This prevents thermal degradation of compound (I), allowing the formation of a good thin film. However, when forming a thin film by solution coating, such problems are unlikely to occur, so the molecular weight of compound (I) may be greater than 1000.

[0069] Compound (I) can be synthesized, for example, according to the following scheme.

[0070] More specifically, for example, a commercially available compound (A) can be reacted with compound (B) to obtain a compound represented by formula (I) represented by X １ Further, compound (E) can be obtained by an addition reaction of compound (D), and compound (E) can be obtained by a reaction using compound (B) to obtain compound (C) in the formula (I). １ NR ３ In addition, compound (F) having the desired R and R ２ After the reaction using compound (B), R, R ２ Alternatively, after the reaction using compound (B), compound (F) may be obtained by an addition reaction of compound (D).

[0071] Compound (I) of this embodiment can be obtained, for example, by synthesis as described above. In the product (100% by mass) obtained by synthesis, the content of compound (I) is preferably 90% by mass or more, more preferably 93% by mass, and even more preferably 97% by mass or more. By having a content of compound (I) of 90% by mass or more, carrier trapping at impurity levels caused by unintended impurities when compound (I) is used in a photoelectric conversion element or an imaging element can be more effectively and reliably avoided. As a result, carrier recombination is suppressed, and a photoelectric conversion element or an imaging element with superior performance can be obtained. The content can be measured by liquid chromatography, gas chromatography, elemental analysis, or the like, but any known method can be used.

[0072] (Photoelectric conversion element material) A compound represented by the following formula (I): The compound represented by the formula (I) is used as a material for a photoelectric conversion element. ３ and X ２ is a nitrogen atom or CR ４ and X ３ is a nitrogen atom or CR ５ n is an integer of 0 to 3, and R １ , R ２ , R ３ , R ４ and R ５ are each independently selected from the group consisting of a hydrogen atom, a halogen atom, a hydroxy group, a thiol group, an amino group, a cyano group, a carboxy group, a nitro group, and an optionally substituted linear, branched, or cyclic alkyl group, a thioalkyl group, a thioaryl group, an arylsulfonyl group, an aryloxy group, an alkylsulfonyl group, an alkylamino group, an arylamino group, an alkoxy group, an acylamino group, an acyloxy group, an aryl group, a carboxamido group, a carboalkoxy group, a carboaryloxy group, an acyl group, and a monovalent heterocyclic group; １ , R ２ , R ４ and R ５may be part of a fused ring, and the fused ring may contain one or more atoms other than carbon atoms. ２ , X ３ , R １ ~R ５ Preferred embodiments of n and n are as described above, provided that the compound (I) used as a material for a photoelectric conversion element includes compounds represented by the formula (II) and formula (III).

[0073] More specifically, as a photoelectric conversion element material, Compound (I) is used as a material contained in each layer of a photoelectric conversion element described below. Among them, from the viewpoint of more effectively and reliably exhibiting the effects of the present invention, Compound (I) is preferably contained in a photoelectric conversion film, more preferably in an auxiliary layer, and particularly preferably in at least one of an electron transport layer and a hole blocking layer.

[0074] Furthermore, compound (I) of this embodiment can be used as a photosensitive material as is, or can be mixed with other materials to form a photosensitive composition. The content of compound (I) in the photosensitive composition may be 50% by mass or more, based on the total amount of the composition. Furthermore, the content may be 95% by mass or less, 90% by mass or less, or 80% by mass or less. Materials other than compound (I) in the photosensitive composition are not particularly limited, as long as they are contained in ordinary photosensitive compositions. Examples of such materials include n-type semiconductor materials, p-type semiconductor materials, and light-absorbing materials, which will be described later. These materials may be used alone or in combination of two or more.

[0075] (Organic Thin Film) The organic thin film of this embodiment includes the compound (I) of this embodiment or the above-described photoelectric conversion element material. Such an organic thin film can be produced by a general dry film formation method or wet film formation method. Specific examples include vacuum processes such as resistance heating evaporation, electron beam evaporation, sputtering, and molecular lamination; solution processes such as casting, spin coating, dip coating, blade coating, wire bar coating, and spray coating; printing methods such as inkjet printing, screen printing, offset printing, and relief printing; and soft lithography methods such as microcontact printing. Generally, from the perspective of ease of processing, it is desirable that the material for a photoelectric conversion element can be used in a process in which the compound is applied in a solution state. However, in the case of a photoelectric conversion element in which organic thin films are laminated, a dry film formation method such as resistance heating evaporation is preferred because the coating solution may corrode the underlying film.

[0076] For example, in a dry film formation method, the photoelectric conversion element material of this embodiment and, if necessary, other materials appropriate for the application of the photoelectric conversion element are mixed to form a composition, and the composition is vapor-deposited under vacuum onto a substrate or other film, thereby obtaining an organic thin film. In a wet film formation method, the photoelectric conversion element material of this embodiment and, if necessary, other materials appropriate for the application of the photoelectric conversion element are mixed with a solvent to form a liquid composition, which is coated and printed onto a substrate or other film, and then dried, thereby obtaining an organic thin film.

[0077] The organic thin film of this embodiment may contain a material other than Compound (I), which is the photoelectric conversion element material of this embodiment. The content of Compound (I) in the organic thin film of this embodiment is not particularly limited as long as the performance required for use as a photoelectric conversion element material is exhibited. For example, the content may be 50% by mass or more relative to the total amount of the organic thin film. However, from the viewpoint of more effectively and reliably achieving the effects of the present invention, the content is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more. The upper limit of the content may be 100% by mass. When the organic thin film of this embodiment contains a material other than Compound (I), the material is not particularly limited as long as it is used as a typical material for photoelectric conversion elements. Examples of such materials include n-type semiconductor materials, p-type semiconductor materials, and light-absorbing materials described below, as well as molybdenum oxide, alkali metals, and alkali metal compounds, which are called doping materials. These may be used alone or in combination of two or more.

[0078] The thickness of the organic thin film cannot be limited because it depends on the resistance value and charge mobility of each substance, but is usually 0.5 nm or more and 5000 nm or less, and may be 1 nm or more and 1000 nm or less, or 5 nm or more and 500 nm or less.

[0079] In order to more effectively and reliably achieve the effects of the present invention, the organic thin film of this embodiment preferably has a maximum absorption wavelength in the light absorption band of 450 nm or less.

[0080] (Photoelectric Conversion Element) The photoelectric conversion element of this embodiment generates charges according to the amount of incident light, and outputs the generated charges to the outside of the photoelectric conversion element via a capacitor (hereinafter also referred to as an "accumulation unit") for storing the generated charges, a transistor circuit (hereinafter also referred to as a "readout unit") for reading them out, and the like. Here, the photoelectric conversion element refers to a photoelectric conversion film that absorbs at least a portion of incident light disposed between a pair of opposing electrodes, and light is incident on the photoelectric conversion element from above the electrodes. The photoelectric conversion film is a photosensitive thin film containing a material that absorbs at least a portion of incident light in the infrared range, and generates holes and electrons as a result of the light incidence. The photoelectric conversion element of this embodiment may also have a photoelectric conversion element (hereinafter also referred to as an "infrared photoelectric conversion element") that generates charges according to the amount of incident light in the infrared range, where the infrared photoelectric conversion element is a photoelectric conversion film (hereinafter also referred to as an "infrared photoelectric conversion film") that absorbs infrared light disposed between a pair of opposing electrodes, and light is incident on the infrared photoelectric conversion element from above the electrodes. The infrared photoelectric conversion film is a photosensitive thin film containing a material that absorbs at least a portion of incident light in the infrared range (hereinafter also referred to as an "infrared absorbing material"), and generates holes and electrons as a result of the incidence of light.

[0081] The photoelectric conversion element of this embodiment will be described with appropriate reference to Fig. 1. The photoelectric conversion element 100 includes a lower electrode 102 which is a first electrode film, an upper electrode 106 which is a second electrode film, and a photoelectric conversion film 110 located between the lower electrode 102 and the upper electrode 106. The photoelectric conversion element 100 may include a substrate 101, which is normally insulating, on the side of the upper electrode 106 opposite the photoelectric conversion film 110.

[0082] When the photoelectric conversion film 110 has hole transport properties or electron transport properties, the lower electrode 102 and the upper electrode 106 serve to extract and collect holes from the photoelectric conversion film 110, or to extract and eject electrons. Materials that can be used as these electrodes are not particularly limited as long as they have a certain degree of conductivity, but are preferably selected taking into consideration adhesion to the adjacent photoelectric conversion film 110, electron affinity, ionization potential, stability, and the like. Materials that can be used as electrodes include, for example, conductive metal oxides such as tin oxide (NESA), indium oxide, indium tin oxide (ITO), and indium zinc oxide (IZO); metals such as gold, silver, platinum, chromium, aluminum, iron, cobalt, nickel, and tungsten; inorganic conductive substances such as copper iodide and copper sulfide; conductive polymers such as polythiophene, polypyrrole, and polyaniline; and carbon. These materials may be used alone or in combination.

[0083] The lower electrode 102, which is the first electrode film, is made of a light-transmitting conductive film, such as indium tin oxide (ITO). The material for the lower electrode 102 is not limited to ITO, but includes, for example, tin oxide (SnO)-based materials with dopants added and zinc oxide-based materials with dopants added to zinc oxide (ZnO). Examples of zinc oxide-based materials include aluminum zinc oxide (AZO) with aluminum (Al) added as a dopant, gallium zinc oxide (GZO) with gallium (Ga) added, and indium zinc oxide (IZO) with indium (In) added. Alternatively, examples of materials for the lower electrode 102 include CuI, InSbO, ZnMgO, CuInO, MgINO, CdO, and ZnSnO. The thickness of the lower electrode 102 is, for example, 5 nm or more and 3000 nm or less, and may be 5 nm or more and 500 nm or less, or 10 nm or more and 300 nm or less.

[0084] The upper electrode 106, which is the second electrode film, may be made of a conductive film having the same optical transparency as the lower electrode 102, or may be made of a metal such as aluminum that is commonly used for electrodes of photoelectric conversion elements. In a solid-state imaging device using a solid-state imaging element as one pixel, the upper electrode 106 may be separated for each pixel, or may be formed as an electrode common to all pixels. The thickness of the upper electrode 106 is, for example, 5 nm to 3000 nm, or may be 5 nm to 500 nm, or may be 10 nm to 300 nm.

[0085] The conductivity of the materials used for electrodes such as the first electrode film and the second electrode film is not particularly limited as long as it does not unnecessarily interfere with the light reception of the photoelectric conversion element, but it is preferable that the conductivity be as high as possible from the perspective of the signal strength and power consumption of the photoelectric conversion element. For example, as a transparent electrode, an ITO film having a conductivity of 300 Ω / □ or less will function sufficiently as an electrode. However, commercially available substrates with ITO films having a conductivity of several Ω / □ (e.g., 5 to 9 Ω / □) are also available, and substrates with such high conductivity are desirable.

[0086] When an ITO film is used, the thickness of the electrode can be selected arbitrarily taking into consideration the conductivity, but is usually 5 nm to 3000 nm, preferably 10 nm to 300 nm. Methods for forming films such as ITO include conventionally known vapor deposition methods, electron beam methods, sputtering methods, chemical reaction methods, and coating methods. The ITO film provided on the substrate may be subjected to UV-ozone treatment or plasma treatment as necessary.

[0087] Furthermore, when multiple photoelectric conversion films with different detection wavelengths are stacked, the electrode film used between each photoelectric conversion film needs to transmit light of wavelengths other than the light detected by each photoelectric conversion film. From this perspective, it is preferable to use a material that transmits 90% or more of the incident light for the electrode film, and it is more preferable to use a material that transmits 95% or more of the light. Note that the electrode film is a film of an electrode other than the pair of electrodes described above.

[0088] Furthermore, when a visible photoelectric conversion section that senses infrared light or light in a different visible light range is further provided below the photoelectric conversion element in this embodiment, the electrodes used in the photoelectric conversion element preferably have a transmittance of 90% or more for visible light and infrared light, and more preferably 95% or more.

[0089] A preferred electrode material that satisfies these conditions is a transparent conducting oxide (TCO), which has high transmittance to visible light and infrared light and low resistance. Thin metal films such as gold can also be used as electrodes, but increasing the transmittance to 90% or more results in a significant increase in resistance. Therefore, TCOs are preferred for electrodes. ITO, IZO, AZO, FTO, SnO2, TiO2, and ZnO2 are particularly preferred TCOs.

[0090] The method for forming the electrode is not particularly limited and can be appropriately selected taking into consideration the suitability for the electrode material. When a transparent electrode is used, specific examples of the formation method 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. Furthermore, when the electrode material is a transparent conductive metal oxide such as ITO, examples of the formation method include an electron beam method, sputtering, resistance heating vapor deposition, chemical reaction methods (e.g., a sol-gel method), and a method of applying a dispersion of the metal oxide. Furthermore, a film of a transparent conductive metal oxide such as ITO can also be subjected to UV-ozone treatment and plasma treatment.

[0091] Furthermore, from the viewpoint of more effectively and reliably achieving the effects of the present invention, the photoelectric conversion element of this embodiment is a photoelectric conversion element comprising a first electrode film, a second electrode film, and a photoelectric conversion film located between the first electrode film and the second electrode film, and the photoelectric conversion film comprises a photoelectric conversion layer and two auxiliary layers located between the photoelectric conversion layer and the second electrode film, and it is preferable that of the two auxiliary layers, the auxiliary layer closest to the second electrode film contains compound (I) of this embodiment.

[0092] The reason why such a photoelectric conversion element can suppress leakage current in the dark is unclear, but the inventors believe it to be as follows. The photoelectric conversion element of this embodiment has two auxiliary layers between the photoelectric conversion layer and the second electrode film, and one of the auxiliary layers closest to the second electrode film contains compound (I). This is thought to result in a rectification effect that suppresses the movement of electrons generated in the photoelectric conversion layer to the second electrode film due to the relatively low HOMO level of compound (I), thereby making it possible to suppress leakage current in the dark (hereinafter also referred to as "dark current"). However, this is not a limiting factor. The photoelectric conversion element of this embodiment can also have high photoelectric conversion efficiency. This is thought to be because the auxiliary layer close to the second electrode film contains compound (I), which increases the chemical affinity between the second electrode film and the photoelectric conversion film and makes the energy gradient for moving electrons to the second electrode film smoother. However, this is not a limiting factor.

[0093] In one aspect of this embodiment, the photoelectric conversion film 110 may include the photoelectric conversion element material of this embodiment or the organic thin film described above. More specifically, for example, the photoelectric conversion film 110 includes a photoelectric conversion layer 104, a first auxiliary layer 103 located on the lower electrode film 102 side of the photoelectric conversion layer 104, and a second auxiliary layer 105 located on the upper electrode film 106 side of the photoelectric conversion layer 104. While the photoelectric conversion film 110 shown in FIG. 1 includes the first auxiliary layer 103 and the second auxiliary layer 105, the photoelectric conversion film may include only one of these auxiliary layers. Alternatively, the photoelectric conversion film may include only the photoelectric conversion layer 104 without any auxiliary layer. When the photoelectric conversion film does not include an auxiliary layer, the photoelectric conversion layer 104 is the organic thin film described above. When the photoelectric conversion film includes an auxiliary layer, at least one of the photoelectric conversion layer 104 and the auxiliary layer is the organic thin film described above. However, from the viewpoint of more effectively and reliably achieving the effects of the present invention, the auxiliary layer is preferably the organic thin film containing the material for a photoelectric conversion element of this embodiment.

[0094] As one aspect of this embodiment, the photoelectric conversion film 110 includes a photoelectric conversion layer 104, and a second auxiliary layer 105 and a third auxiliary layer 107 located between the photoelectric conversion layer 104 and the upper electrode 106, and of the auxiliary layers 105 and 107, the third auxiliary layer 107, which is closer to the upper electrode 106, is adjacent to the upper electrode 106, and the second auxiliary layer 105 is located on the photoelectric conversion layer 104 side of the third auxiliary layer 107. Note that although the photoelectric conversion film 110 shown in FIG. 2 includes the first auxiliary layer 103, the second auxiliary layer 105, and the third auxiliary layer 107, the photoelectric conversion film does not necessarily have to include an auxiliary layer between the lower electrode 102 and the photoelectric conversion layer 104.

[0095] The photoelectric conversion layer 104 may be an organic semiconductor film generally used as a photoelectric conversion layer, or may be the organic thin film described above. Furthermore, in the photoelectric conversion layer 104, the organic semiconductor film and organic thin film may be one layer or multiple layers. When there is one layer, a p-type organic semiconductor film, an n-type organic semiconductor film, or a mixed film thereof (hereinafter, this may be a "bulk heterostructure") is used. On the other hand, when there are multiple layers, the number of layers may be about 2 to 10, and the structure may be a stack of p-type organic semiconductor films, n-type organic semiconductor films, or a mixed film thereof (hereinafter, this may be a "bulk heterostructure"), with a buffer layer inserted between the layers.

[0096] The photoelectric conversion layer 104 in this embodiment may or may not contain the photoelectric conversion element material of this embodiment, and may contain a material other than the photoelectric conversion element material of this embodiment. Among these, the photoelectric conversion layer 104 preferably contains at least one of an organic p-type semiconductor, an organic n-type semiconductor, and a light-absorbing material, since incident light energy of a desired wavelength can be converted into an electrical signal more efficiently. Among these, organic p-type semiconductors that readily donate electrons and have a small ionization potential, or organic n-type semiconductors that readily accept electrons and have a large electron affinity, are preferred, since they can convert incident light energy into an electrical signal more efficiently. Here, the ionization potential (HOMO level) refers to a value measured by photoelectron yield spectroscopy or photoelectron spectroscopy. The electron affinity (LUMO level) refers to a value obtained by calculating the energy band gap value from the longest wavelength absorption edge of the near-infrared spectroscopy spectrum and subtracting it from the HOMO level, or a value measured by inverse photoelectron spectroscopy.

[0097] When an organic semiconductor film is used, the film may be one layer or two or more layers. The organic semiconductor film may be an organic p-type semiconductor film, an organic n-type semiconductor film, a light-absorbing material film, or a mixed film thereof (bulk heterostructure). In particular, the organic semiconductor film preferably has a bulk heterojunction structure layer. In such a case, by incorporating a bulk heterojunction structure into the photoelectric conversion film, the drawback of the short carrier diffusion length of the photoelectric conversion film can be compensated for, and the photoelectric conversion efficiency can be improved.

[0098] The thickness of the photoelectric conversion layer 104 may be, for example, 0.5 nm or more and 5000 nm or less, 1 nm or more and 1000 nm or less, or 5 nm or more and 500 nm or less.

[0099] The organic semiconductor will be described in detail below.

[0100] An organic p-type semiconductor is a donor organic semiconductor (hereinafter also referred to as a "donor organic compound"), and is an organic compound that has the property of readily donating electrons, mainly represented by a hole-transporting organic compound. More specifically, it refers to the organic compound that has the smaller ionization potential when two organic materials are used in contact. Therefore, any organic compound that has electron-donating properties can be used as a donor organic compound.

[0101] Examples of such donor organic compounds include triarylamine compounds, benzidine compounds, pyrazoline compounds, styrylamine compounds, hydrazone compounds, triphenylmethane compounds, carbazole compounds, polysilane compounds, thiophene compounds, phthalocyanine compounds, cyanine compounds, merocyanine compounds, oxonol compounds, polyamine compounds, indole compounds, pyrrole compounds, pyrazole compounds, polyarylene compounds, condensed aromatic carbon ring compounds (e.g., naphthalene derivatives, anthracene derivatives, phenanthrene derivatives, tetracene derivatives, pyrene derivatives, perylene derivatives, fluoranthene derivatives), and metal complexes having nitrogen-containing heterocyclic compounds as ligands.In addition, without being limited to these, as described above, any organic compound having a smaller ionization potential than the organic compound used as the acceptor organic compound can be used as the donor organic semiconductor.

[0102] An organic n-type semiconductor is an acceptor organic semiconductor (hereinafter also referred to as an "acceptor organic compound"), and is mainly represented by an electron-transporting organic compound, and refers to an organic compound that has the property of readily accepting electrons. More specifically, when two organic compounds are used in contact with each other, the organic compound that has the greater electron affinity is the one that is used. Therefore, any organic compound that has electron-accepting properties can be used as an acceptor organic compound.

[0103] Examples of such acceptor organic compounds include condensed aromatic carbocyclic compounds (e.g., naphthalene derivatives, anthracene derivatives, phenanthrene derivatives, tetracene derivatives, pyrene derivatives, perylene derivatives, fluoranthene derivatives, and fullerene derivatives), 5- to 7-membered heterocyclic compounds containing a nitrogen atom, an oxygen atom, or a sulfur atom (e.g., pyridine, pyrazine, pyrimidine, pyridazine, triazine, quinoline, quinoxaline, quinazoline, phthalazine, cinnoline, isoquinoline, pteridine, acridine, phenazine, phenanthroline, tetrazole, Examples of the metal complexes include those having a pyrazole, imidazole, thiazole, oxazole, indazole, benzimidazole, benzotriazole, benzoxazole, benzothiazole, carbazole, purine, triazolopyridazine, triazolopyrimidine, tetrazaindene, oxadiazole, imidazopyridine, pyrazine, pyrrolopyridine, thiadiazolopyridine, dibenzazepine, and tribenzazepine), a polyarylene compound, a fluorene compound, a cyclopentadiene compound, a silyl compound, and a nitrogen-containing heterocyclic compound as a ligand. Note that, without being limited to these, as described above, any organic compound having a larger electron affinity than the organic compound used as the donor organic compound can be used as the acceptor organic semiconductor.

[0104] The light-absorbing material is a compound having a maximum light absorption wavelength in the visible light region, particularly in the range of 450 nm to 650 nm. The absorption intensity of the light-absorbing material at the maximum light absorption wavelength is desirably greater than the absorption intensity of the donor organic compound or the acceptor organic compound at the maximum light absorption wavelength. By having such an absorption intensity, incident light can be selectively absorbed at the maximum light absorption wavelength of the light-absorbing material. After incident light is absorbed by the light-absorbing material and photons become excitons, exciton dissociation occurs at the interface between the donor organic compound and the acceptor organic compound, allowing hole and electron carriers to be efficiently generated.

[0105] As such a light-absorbing material, compounds generally called dyes can be used, for example, phthalocyanine derivatives, subphthalocyanine derivatives, quinacridone derivatives, porphyrin derivatives, naphthalene or perylene derivatives, phthaloperylene derivatives, styryl derivatives, cyanine derivatives, hemicyanine derivatives, merocyanine derivatives, rhodacyanine derivatives, oxonol derivatives, hemioxonol derivatives, croconium derivatives, squarylium derivatives, azamethine derivatives, arylidene derivatives, azo derivatives, azomethine derivatives, metallocene derivatives, fulgide derivatives, phenazine derivatives, phenothiazine derivatives, polyene derivatives, acridine derivatives, acridinone derivatives, diphenylamine derivatives, triarylamine derivatives such as triphenylamine, naphthylamine, and styrylamine, quinophthalone derivatives, phenoxazine derivatives, chlorophyll derivatives, rhodamine derivatives, diphenylmethane or triphenylmethane derivatives, xanthene derivatives, acridine derivatives, phenoxazine derivatives, quinoline derivatives, oxazine derivatives, thiazine derivatives, quinone derivatives, benzoquinone derivatives, naphthoquinone derivatives, anthraquinone derivatives, indigo or thioindigo derivatives, pyrrole derivatives, pyridine derivatives, dipyrrine derivatives, indole derivatives, diketopyrrolopyrrole derivatives, coumarin derivatives, fluorene derivatives, fluorenone derivatives, fluoranthene derivatives, anthracene derivatives, pyrene derivatives, carbazole derivatives, phenylenediamine derivatives, benzidine derivatives, phenanthroline derivatives, imidazole derivatives, oxazoline derivatives, thiazoline derivatives, triazole derivatives, thiadiazole derivatives, oxazole derivatives, thiazole derivatives, oxadiazole derivatives, thiophene derivatives, selenophene derivatives, silole derivatives, germole derivatives, stilbene derivatives, phenylenevinylene derivatives, pentacene derivatives, rubrene derivatives, thienothiophene derivatives, benzodithiophene derivatives, xanthenoxanthene derivatives, and fullerene derivatives. However, the light-absorbing material is not limited to these, and as described above, any compound having an absorption intensity greater than the absorption intensity at the maximum light absorption wavelength of the donor organic compound or the acceptor organic compound can be used as the light-absorbing material.The light-absorbing material can also serve as a donor organic compound or an acceptor organic compound.

[0106] In one aspect of this embodiment, the first auxiliary layer 103 may be a single layer or two or more layers. The first auxiliary layer 103 includes, for example, at least one of a hole blocking layer and an electron transport layer. When the first auxiliary layer 103 includes two of these layers, the electron transport layer and the hole blocking layer are typically stacked in this order, starting from the photoelectric conversion layer 104 side. The electron transport layer transports electrons generated in the photoelectric conversion layer 104 to the first electrode 102 and blocks holes from moving from the first electrode 102 to the photoelectric conversion layer 104. The hole blocking layer prevents holes from moving from the first electrode 102 to the photoelectric conversion layer 104, preventing recombination within the photoelectric conversion layer 104, reducing dark current, reducing noise, and expanding the dynamic range. Alternatively, one layer may function as both a hole blocking layer and an electron transport layer. From the viewpoint of suppressing dark current and preventing a decrease in photoelectric conversion efficiency, the thickness of the first auxiliary layer 103 is preferably 10 nm or more and 300 nm or less, more preferably 30 nm or more and 250 nm or less, and even more preferably 50 nm or more and 200 nm or less.

[0107] In one aspect of this embodiment, the second auxiliary layer 105 may be a single layer or two or more layers. The second auxiliary layer 105 includes, for example, at least one of an electron blocking layer and a hole transport layer. When the second auxiliary layer 105 includes two of these layers, the hole transport layer and the electron blocking layer are typically stacked in this order, starting from the photoelectric conversion layer 104 side. The hole transport layer transports generated holes from the photoelectric conversion layer 104 to the second electrode 106 and blocks electrons from moving from the second electrode 106 to the photoelectric conversion layer 104. The electron blocking layer prevents electrons from moving from the second electrode 106 to the photoelectric conversion layer 104, preventing recombination within the photoelectric conversion layer 104, reducing dark current and noise, thereby expanding the dynamic range. Alternatively, one layer may function as both an electron blocking layer and a hole transport layer. From the viewpoint of suppressing dark current and preventing a decrease in photoelectric conversion efficiency, the thickness of the second auxiliary layer 105 is preferably 5 nm or more and 200 nm or less, more preferably 15 nm or more and 130 nm or less, and even more preferably 25 nm or more and 100 nm or less.

[0108] In one aspect of this embodiment, the third auxiliary layer 107 is an auxiliary layer closer to the upper electrode 106 than the second auxiliary layer 105, and may be, for example, a hole-blocking layer. The hole-blocking layer prevents holes from moving from the second electrode 106 to the photoelectric conversion layer 104, prevents recombination within the photoelectric conversion layer 104, reduces dark current, reduces noise, and expands the dynamic range. At least one layer between the photoelectric conversion layer 104 and the upper electrode 106 may function as both a hole-blocking layer and an electron-transporting layer. From the viewpoints of suppressing dark current and preventing a decrease in photoelectric conversion efficiency, the thickness of the third auxiliary layer 107 is preferably 5 nm to 200 nm, more preferably 15 nm to 130 nm, and even more preferably 25 nm to 100 nm.

[0109] The material for photoelectric conversion elements of this embodiment may be contained in any of the first auxiliary layer 103, the second auxiliary layer 105, and the third auxiliary layer 107, but is preferably contained in the first auxiliary layer 103 or / and the third auxiliary layer 107. In the photoelectric conversion element of this embodiment, of the first auxiliary layer 103, the second auxiliary layer 105, and the third auxiliary layer 107, it is preferable that the first auxiliary layer 103 or / and the third auxiliary layer 107 contain the above-mentioned organic thin film. Furthermore, it is more preferable that the material for photoelectric conversion elements of this embodiment be contained in at least one of the hole blocking layer and the electron transport layer in the first auxiliary layer 103 or / and the third auxiliary layer 107. In the photoelectric conversion element of this embodiment, it is preferable that at least one of the hole blocking layer and the electron transport layer is the above-mentioned organic thin film. This makes it possible to more effectively and reliably achieve the effects of the present invention.

[0110] In one aspect of this embodiment, compound (I) of this embodiment is contained in at least the third auxiliary layer 107 among these auxiliary layers. The third auxiliary layer 107 may contain a material other than compound (I). The content of compound (I) in the third auxiliary layer 107 is not particularly limited as long as it exhibits the performance required for use as an auxiliary layer close to the upper electrode 106. For example, the content may be 50% by mass or more of the total amount of the third auxiliary layer 107. However, from the viewpoint of more effectively and reliably achieving the effect of suppressing leakage current in the dark according to the present invention, the content is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more. The upper limit of the content may be 100% by mass.

[0111] The compound (I) of this embodiment and materials other than the material for a photoelectric conversion element that can be contained in each layer of the auxiliary layer will be described below.

[0112] The material for the hole transport layer is not particularly limited as long as it is known as a material for a hole transport layer in a photoelectric conversion element such as a solid-state imaging element, and examples thereof include polyaniline and doped materials thereof, and the cyan compounds described in WO 2006 / 019270.

[0113] More specifically, materials constituting the hole transport layer include selenium, iodides such as copper iodide (CuI), cobalt complexes such as layered cobalt oxides, CuSCN, molybdenum oxide (MoO, etc.), nickel oxide (NiO, etc.), 4CuBr.3S(C4H9), and organic hole transport materials. Among these, an example of an iodide is copper iodide (CuI). An example of a layered cobalt oxide is AxCoO2 (where A represents Li, Na, K, Ca, Sr, or Ba, and 0≦X≦1). Examples of organic hole transport materials include polythiophene derivatives such as poly-3-hexylthiophene (P3HT), poly(3,4-ethylenedioxythiophene), (PEDOT; for example, trade name "Baytron P" manufactured by Starck-V-Tech), fluorene derivatives such as 2,2',7,7'-tetrakis-(N,N-di-p-methoxyphenylamine)-9,9'-spirobifluorene (spiro-MeO-TAD), carbazole derivatives such as polyvinylcarbazole, triphenylamine derivatives, diphenylamine derivatives, polysilane derivatives, and polyaniline derivatives. Further, examples of materials for the hole transport layer include compound semiconductors containing monovalent copper, such as CuInSe and copper sulfide (CuS), gallium phosphide (GaP), nickel oxide (NiO), cobalt oxide (CoO), iron oxide (FeO), bismuth oxide (BiO), molybdenum oxide (MoO), and chromium oxide (CrO).

[0114] Furthermore, it is preferable that the hole transport layer has a LUMO level higher than that of the photoelectric conversion film, since this layer has a rectifying effect that suppresses the movement of electrons generated in the photoelectric conversion film toward the electrode, and thus has an electron blocking function. Such a hole transport layer is also called an electron blocking layer.

[0115] Among the materials constituting the electron blocking layer, examples of low molecular weight organic compounds include aromatic diamine compounds such as N,N'-bis(3-methylphenyl)-(1,1'-biphenyl)-4,4'-diamine (TPD) and 4,4'-bis[N-(naphthyl)-N-phenyl-amino]biphenyl (α-NPD), oxazole, oxadiazole, triazole, imidazole, imidazolone, stilbene derivatives, pyrazoline derivatives, tetrahydroimidazole, polyarylalkane, butadiene, 4,4',4''-tris(N-(3-methylphenyl)N-phenyl) Examples of suitable organic compounds include porphyrin compounds such as m-methylaminotriphenylamine (m-MTDATA), porphyrin, tetraphenylporphyrin copper, phthalocyanine, copper phthalocyanine, and titanium phthalocyanine oxide, triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, and silazane derivatives. Examples of suitable organic polymer compounds include polymers of phenylene vinylene, fluorene, carbazole, indole, pyrene, pyrrole, picoline, thiophene, acetylene, and diacetylene, as well as derivatives thereof. Even if the compound is not an electron-donating compound, any compound having sufficient hole-transporting properties can be used as a material for forming the electron blocking layer. Furthermore, among the materials constituting the electron blocking layer, examples of inorganic compounds include metal oxides such as calcium oxide, chromium oxide, chromium copper oxide, manganese oxide, cobalt oxide, nickel oxide, copper oxide, gallium copper oxide, strontium copper oxide, niobium oxide, molybdenum oxide, indium copper oxide, indium silver oxide, and iridium oxide, as well as selenium, tellurium, and antimony sulfide. These may be used alone or in combination of two or more.

[0116] From the viewpoint of suppressing dark current and preventing a decrease in photoelectric conversion efficiency, the thickness of the hole transport layer is preferably 10 nm or more and 300 nm or less, more preferably 30 nm or more and 250 nm or less, and even more preferably 50 nm or more and 200 nm or less.

[0117] The hole transport layer and the electron blocking layer may be formed by a conventional method, such as a dry film-forming method (e.g., vacuum deposition) or a wet film-forming method (e.g., solution coating). However, from the viewpoint of leveling the coating surface, a wet film-forming method is preferred. Examples of dry film-forming methods include vapor deposition (e.g., vacuum deposition) and sputtering. Vapor deposition may be either physical vapor deposition (PVD) or chemical vapor deposition (CVD), with physical vapor deposition (e.g., vacuum deposition) being preferred. Examples of wet film-forming methods include inkjet printing, spraying, nozzle printing, spin coating, dip coating, casting, die coating, roll coating, bar coating, and gravure coating.

[0118] The material for constituting the electron transport layer is not particularly limited as long as it is known as an electron transport layer in a photoelectric conversion element such as a solid-state imaging element. Examples of the material include organic compounds such as octaazaporphyrin and perfluorinated p-type semiconductors (e.g., perfluoropentacene and perfluorophthalocyanine), fullerene, fullerene derivatives (e.g., [6,6]-phenyl-C61-butylic acid methyl ester; PCBM), perylene, indenoindene, and indenoindene derivatives, and inorganic oxides such as titanium oxide (TiO2, etc.), nickel oxide (NiO), tin oxide (SnO2), tungsten oxide (WO2, WO3, W2O3, etc.), zinc oxide (ZnO), niobium oxide (Nb2O5, etc.), tantalum oxide (Ta2O5, etc.), yttrium oxide (YO3, etc.), and strontium titanate (SrTiO3, etc.). The electron transport layer may be porous or dense, and when they are laminated, it is preferable that the porous electron transport layer and the dense electron transport layer are laminated in this order from the photoelectric conversion film side.

[0119] Furthermore, it is preferable that the electron transport layer has a HOMO level lower than that of the photoelectric conversion film, because this layer has a rectification effect that suppresses the migration of holes generated in the photoelectric conversion film toward the counter electrode, and thus has a hole-blocking function. Such an electron transport layer is also called a hole-blocking layer.

[0120] Examples of materials constituting the hole blocking layer include oxadiazole derivatives such as 1,3-bis(4-tert-butylphenyl-1,3,4-oxadiazolyl)phenylene (OXD-7), anthraquinodimethane derivatives, diphenylquinone derivatives, bathocuproine, bathophenanthroline, and derivatives thereof, triazine compounds, triazole compounds, tris(8-hydroxyquinolinato)aluminum complexes, bis(4-methyl-8-quinolinato)aluminum complexes, silole compounds, and porphyrins. n-type semiconductor materials such as styryl compounds, DCM (4-dicyanomethylene-2-methyl-6-(4-(dimethylaminostyryl))-4H-pyran), naphthalene tetracarboxylic anhydride (NTCDA), naphthalene tetracarboxylic diimide, perylene tetracarboxylic anhydride (PTCDA), and perylene tetracarboxylic diimide; n-type inorganic oxides such as titanium oxide, zinc oxide, and gallium oxide; and alkali metal fluorides such as lithium fluoride, sodium fluoride, and cesium fluoride. Furthermore, organic semiconductor molecules doped with alkali metal compounds are also preferred, as they have the function of improving electrical connection with the counter electrode. These may be used alone or in combination of two or more.

[0121] From the viewpoint of suppressing dark current and preventing a decrease in photoelectric conversion efficiency, the thickness of the electron transport layer is preferably 10 nm or more and 300 nm or less, more preferably 30 nm or more and 250 nm or less, and even more preferably 50 nm or more and 200 nm or less.

[0122] The method for forming the electron transport layer and the hole blocking layer may be a conventional method, and may be either a dry film-forming method such as vacuum deposition or a wet film-forming method such as solution coating. However, from the viewpoint of leveling the coating surface, a wet film-forming method is preferred. Examples of dry film-forming methods include vapor deposition methods such as vacuum deposition and sputtering. Vapor deposition may be either physical vapor deposition (PVD) or chemical vapor deposition (CVD), with physical vapor deposition such as vacuum deposition being preferred. Examples of wet film-forming methods include inkjet printing, spraying, nozzle printing, spin coating, dip coating, casting, die coating, roll coating, bar coating, and gravure coating.

[0123] The photoelectric conversion element of this embodiment may include a single or two or more auxiliary layers, separate from the first auxiliary layer 103, between the first auxiliary layer 103 and the lower electrode 102. Examples of such auxiliary layers include a hole injection layer that improves hole injection from the lower electrode 102 to the first auxiliary layer 103. Examples of materials that can be used to form the hole injection layer include phthalocyanine derivatives, starburst amines such as m-MTDATA (4,4',4''-tris[phenyl(m-tolyl)amino]triphenylamine), polythiophenes such as PEDOT (poly(3,4-ethylenedioxythiophene)), and polymeric materials such as polyvinylcarbazole derivatives. The thickness of this auxiliary layer may be the same as that of the first auxiliary layer 103.

[0124] The photoelectric conversion element of this embodiment may include a single or two or more auxiliary layers, separate from the second auxiliary layer 105, between the second auxiliary layer 105 and the upper electrode 106. Examples of such auxiliary layers include an electron injection layer that improves electron injection from the upper electrode 106 to the second auxiliary layer 105, and an electron transport layer. Examples of materials constituting the electron injection layer include metals such as cesium, lithium, and strontium, as well as lithium fluoride. Materials constituting the electron transport layer may be similar to those described above. Furthermore, the thickness of this auxiliary layer may be similar to that of the second auxiliary layer 105.

[0125] The photoelectric conversion element of this embodiment may include a single or two or more auxiliary layers, other than the second auxiliary layer 105 and the third auxiliary layer 107, between the third auxiliary layer 107 and the upper electrode 106. Examples of such auxiliary layers include an electron injection layer that improves electron injection from the upper electrode 106 to the third auxiliary layer 107, and an electron transport layer. Examples of materials constituting the electron injection layer include metals such as cesium, lithium, and strontium, and lithium fluoride. Materials constituting the electron transport layer may be similar to those described above. Furthermore, the thickness of this auxiliary layer may be similar to that of the second auxiliary layer 105.

[0126] In addition to the above-described layers, the photoelectric conversion element of this embodiment may also include at least one of an interlayer contact improving layer and a crystallization preventing layer located between these layers.

[0127] The interlayer contact improving layer serves to reduce damage to the film immediately below the upper electrode 106, such as the photoelectric conversion film 110, during deposition of the upper electrode 106. In particular, high-energy particles present in the equipment used to deposit the upper electrode 106, such as sputtering particles, secondary electrons, Ar particles, and negative oxygen ions, may collide with the film immediately below, altering its properties and resulting in performance degradation such as increased leakage current and reduced sensitivity. One method for preventing this is to provide an interlayer contact improving layer on top of the film immediately below. Preferred materials for the interlayer contact improving layer include organic compounds such as copper phthalocyanine, NTCDA, PTCDA, [dipyrazino[2,3-F:2',3'-H]quinoxaline-2,3,6,7,10,11-hexacarbonitrile] (HATCN), acetylacetonate complex, and BCP, as well as organic-metal compounds and inorganic compounds such as MgAg and MgO. The appropriate range for the thickness of the interlayer contact improving layer varies depending on the configuration of the photoelectric conversion film, the film thickness of the electrode, etc., but it is preferable that the thickness be 2 nm or more and 500 nm, particularly from the viewpoint of selecting a material that does not absorb in the visible range or using a thin thickness.

[0128] As described above, the photoelectric conversion element of this embodiment is connected to a storage section, which is a capacitor for storing generated charges, and a readout section, which is a transistor circuit for reading out, via a connection section made of a conductive material. Furthermore, the photoelectric conversion element may include a protective structure from the outside air, such as a protective film, a substrate for maintaining strength, a microlens for focusing light, etc., as needed.

[0129] The readout section is provided to read out a signal corresponding to the charge generated in the photoelectric conversion film. The readout section is composed of, for example, a CCD, CMOS circuit, or TFT circuit, and is preferably shielded from light by a light-shielding layer disposed within the insulating layer. The readout circuit is electrically connected to its corresponding electrode via a connection section. To ensure the amount of charge required for readout, a storage section composed of a capacitor or the like may be interposed between the electrode and the connection section. The connection section is embedded in the insulating layer and is a plug or the like for electrically connecting an electrode (e.g., a transparent electrode or a counter electrode) to the readout section. When a component configured in this manner is a solid-state imaging element, when light is incident, the light enters the photoelectric conversion film, generating charge there. Electrons from the generated charge are collected (and stored) by one electrode, and holes are collected by the other electrode. A voltage signal corresponding to the amount of charge is output from the readout section to the outside of the solid-state imaging element.

[0130] (Image capture element) As one aspect of the present embodiment, the image capture element of the present embodiment may be configured similarly to a conventional image capture element as long as it includes the photoelectric conversion element of the present embodiment. For example, the image capture element of the present embodiment includes a large number of photoelectric conversion elements of the present embodiment arranged in an array. That is, by arranging a large number of photoelectric conversion elements in an array, a solid-state image capture element is formed that indicates not only the amount of incident light but also incident position information.

[0131] The imaging element of this embodiment may include one photoelectric conversion element of this embodiment, or may include two or more stacked elements. When two or more photoelectric conversion elements of this embodiment are stacked, each photoelectric conversion element may selectively detect light in different wavelength bands and perform photoelectric conversion. For example, when three or more photoelectric conversion elements of this embodiment are stacked, at least one may acquire a green color signal, at least one may acquire a blue color signal, at least one may acquire a red color signal, and at least one may acquire an infrared color signal. This allows the imaging element to acquire multiple types of color signals in one pixel without using color filters. Furthermore, color signals other than those detected by the photoelectric conversion element of this embodiment may be sensed by a device having a conventionally known silicon photodiode.

[0132] In an imaging element, if a photoelectric conversion element located closer to the light source does not block (i.e., transmits) the absorption wavelength of another photoelectric conversion element located behind it when viewed from the light source side, devices having multiple photoelectric conversion elements or silicon photodiodes may be stacked.

[0133] In the imaging device, from the viewpoint of ease of molding, the photoelectric conversion elements may be partially configured as thin films on the same plane with no structural separation between adjacent photoelectric conversion elements.

[0134] The imaging device of this embodiment may further include a substrate. The substrate is used to manufacture the imaging device by stacking each layer thereon, or to increase the mechanical strength of the imaging device. The type of substrate is not particularly limited, and examples thereof include a semiconductor substrate, a glass substrate, and a plastic substrate.

[0135] (Optical Sensor) The optical sensor of this embodiment may be configured similarly to a conventional optical sensor as long as it includes the image sensor of this embodiment. This optical sensor receives light at the image sensor of this embodiment and outputs an electrical signal corresponding to the amount of light received.

[0136] (Solid-state imaging device) The solid-state imaging device of this embodiment may be configured similarly to a conventional solid-state imaging device as long as it includes the imaging element of this embodiment. The solid-state imaging device of this embodiment may be, for example, a CMOS image sensor, and may include a pixel unit as an imaging area on a semiconductor substrate, and may further include a peripheral circuit unit having a row scanning unit, a horizontal selection unit, a column scanning unit, and a system control unit in a peripheral region of or vertically below the pixel unit. The pixel unit includes the imaging element of this embodiment.

[0137] The photoelectric conversion element of this embodiment has the following advantages due to the use of the photoelectric conversion element material of this embodiment. Specifically, the photoelectric conversion element of this embodiment is less likely to short-circuit or develop pinholes, resulting in a lower dark current value. As a result, the photoelectric conversion element of this embodiment has excellent leakage prevention properties (particularly in the dark). Furthermore, the photoelectric conversion element of this embodiment tends to exhibit a high light-to-dark ratio, in which case it has even better leakage prevention properties. Furthermore, the photoelectric conversion element of this embodiment has excellent hole and electron transport properties despite the fact that the photoelectric conversion element material is less likely to aggregate, resulting in high photoelectric conversion efficiency. Furthermore, the photoelectric conversion element of this embodiment has good heat resistance due to the use of the photoelectric conversion element material of this embodiment, resulting in improved durability in the manufacturing process and in practical environments.

[0138] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. The synthesized compounds were further purified by sublimation as necessary.

[0139] <Synthesis Example 1>

[0140] A mixture obtained by adding 6.0 g of 1,4,5,8-naphthalenetetracarboxylic dianhydride (1) (hereinafter referred to as "compound (1)"; manufactured by Tokyo Chemical Industry Co., Ltd.) and 2.1 g of aniline (manufactured by Tokyo Chemical Industry Co., Ltd.) (1.0 molar equivalent relative to anhydride (1)) to 90 mL of N,N-dimethylformamide (manufactured by Tokyo Chemical Industry Co., Ltd.) was stirred at 150°C for 8 hours. The mixture was then cooled to room temperature, and the solvent was distilled off under reduced pressure. Acetone was added to the solid obtained by distilling off the solvent, and water was gradually added while stirring, and the precipitate was filtered. The precipitate was dissolved in chloroform, and then sodium sulfate was added and the mixture was allowed to stand for 30 minutes. Next, the sodium sulfate was filtered, and the solvent was distilled off under reduced pressure. Compound (2) was obtained as a pale yellow solid through size exclusion chromatography using chloroform as an eluent.

[0141]

[0142] A mixture obtained by adding 2.0 g of compound (2) and 1.2 g (1.5 molar equivalents relative to compound (2)) of 2-aminobenzamide (Tokyo Chemical Industry Co., Ltd.) to 60 mL of acetic acid (Wako Pure Chemical Industries, Ltd., Fujifilm) was heated at 130°C for 8 hours. After cooling to room temperature, methanol was added and the precipitated mixture was filtered. The mixture was further washed with water and methanol to obtain compound (3) as an orange solid. The results of NMR measurement are shown below. １ HNMR (500MHz, DMSO-d6): 9.14 (d, 1H), 8.77-8.70 (m, 3H), 8.28 (dd, 1H) , 7.99-7.94 (m, 1H), 7.89 (d, 1H), 7.71-7.66 (m, 1H), 7.59-7.43 (m, 5H)

[0143] <Synthesis Example 2>

[0144] Compound (4) was obtained in the same manner as in Synthesis Example 1, except that 4-aminophthalonitrile (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of aniline. Then, compound (5) was obtained in the same manner as in Synthesis Example 1, except that compound (4) was used instead of compound (2). The results of NMR measurement thereof are shown below. １HNMR (500MHz, DMSO-d6): 9.16 (d, 1H), 8.81-8.73 (m, 3H), 8.41 (d, 1H), 8.35 (d, 1 H), 8.29 (d, 1H), 8.12 (dd, 1H), 8.01 to 7.97 (m, 1H), 7.90 (d, 1H), 7.72 to 7.67 (m, 1H)

[0145] <Synthesis Example 3>

[0146] 6.0 g of compound (1) and 3.0 g (1.0 molar equivalent relative to compound (1)) of 2-aminobenzamide (manufactured by Tokyo Chemical Industry Co., Ltd.) were added to 90 mL of pyridine (manufactured by Tokyo Chemical Industry Co., Ltd.), and the resulting mixture was stirred at 120°C for 1 hour. Thereafter, the mixture was cooled to room temperature, and the solvent was distilled off under reduced pressure. Methanol was added to the solid obtained by distilling off the solvent, and the mixture was stirred, and the solid was filtered. After filtering the solid, the solvent was distilled off under reduced pressure. The resulting mixture was subjected to size exclusion chromatography using chloroform as an eluent, and a yellow solid, compound (6), was obtained.

[0147]

[0148] 3.0 g of compound (6) was heated at 300°C under vacuum for 1 hour. After that, it was cooled to room temperature, methanol was added thereto, and the solid was filtered. After size exclusion chromatography using chloroform as an eluent, an orange solid, compound (7), was obtained. The results of its NMR measurement are shown below. １ HNMR (500MHz, DMSO-d6): 9.11 (d, 1H), 8.79-8.70 (m, 3H), 8.27 (dd, 1H), 7.99-7.94 (m, 1H), 7.89 (d, 1H), 7.69-7.64 (m, 1H)

[0149] <Synthesis Example 4>

[0150] Compound (8) was obtained in the same manner as in Synthesis Example 3, except that 2-amino-5-trifluoromethylbenzamide (manufactured by Combi-Block) was used instead of 2-aminobenzamide. Next, compound (9) was obtained in the same manner as in Synthesis Example 3, except that compound (8) was used instead of compound (6). The results of NMR measurement thereof are shown below. １HNMR (500MHz, DMSO-d6): 9.18 (d, 1H), 8.78 (d, 1H), 8.75 (s, 2H), 8.51 (d, 1H), 8.29 (dd, 1H), 8.10 (d, 1H)

[0151] <Synthesis Example 5> A mixture obtained by adding 3.0 g of compound (9), 1.2 g of 4-aminobenzonitrile (manufactured by Tokyo Chemical Industry Co., Ltd.) (1.5 molar equivalents relative to compound (9)), and 1.5 mL of 1,8-diazabicyclo[5.4.0]-7-undecene (manufactured by Tokyo Chemical Industry Co., Ltd.) (1.5 molar equivalents relative to compound (9)) to 90 mL of N,N-dimethylformamide (manufactured by Tokyo Chemical Industry Co., Ltd.) was stirred at 150°C for 8 hours. The mixture was then cooled to room temperature, and the solvent was distilled off under reduced pressure. Acetone was added to the solid obtained by distilling off the solvent, and water was gradually added with stirring, and the precipitate was filtered. The precipitate was dissolved in chloroform, and then sodium sulfate was added and the mixture was allowed to stand for 30 minutes. Next, the sodium sulfate was filtered, and the solvent was distilled off under reduced pressure. A yellow solid, compound (10), was obtained through size exclusion chromatography using chloroform as an eluent. The results of NMR measurement are shown below. １ HNMR (500MHz, DMSO-d6): 9.22 (d, 1H), 8.82-8.73 (m, 3H), 8.52 (d, 1H), 8.30 (dd, 1H), 8.11 (d, 1H), 8.08 (d, 2H), 7.73 (d, 2H)

[0152] <Synthesis Example 6>

[0153] Compound (11) was obtained in the same manner as in Synthesis Example 1, except that 3-aminobenzonitrile (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of aniline. Then, compound (12) was obtained in the same manner as in Synthesis Example 1, except that compound (11) was used instead of compound (2). The results of NMR measurement thereof are shown below. １ HNMR (500MHz, DMSO-d6): 9.17 (d, 1H), 8.79-8.73 (m, 3H), 8.30 (dd, 1H), 8.04-7. 96 (m, 3H), 7.91 (d, 1H), 7.89-7.86 (m, 1H), 7.84-7.79 (m, 1H), 7.72-7.67 (m, 1H)

[0154] <Synthesis Example 7>

[0155] Compound (13) was obtained in the same manner as in Synthesis Example 1, except that 4-aminobenzonitrile (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of aniline. Then, compound (14) was obtained in the same manner as in Synthesis Example 1, except that compound (13) was used instead of compound (2). The results of NMR measurement thereof are shown below. １ HNMR (500MHz, DMSO-d6): 9.16 (d, 1H), 8.78-8.71 (m, 3H), 8.29 (dd, 1H), 8. 08 (d, 2H), 8.01 to 7.96 (m, 1H), 7.90 (d, 1H), 7.73 (d, 2H), 7.71 to 7.66 (m, 1H)

[0156] <Synthesis Example 8>

[0157] Compound (15) was obtained in the same manner as in Synthesis Example 3, except that 2-amino-4-trifluoromethylbenzamide (manufactured by Ambeed, Inc.) was used instead of 2-aminobenzamide. Then, compound (16) was obtained in the same manner as in Synthesis Example 3, except that compound (15) was used instead of compound (6). The results of NMR measurement thereof are shown below. １ HNMR (500MHz, DMSO-d6): 9.14 (d, 1H), 8.77 (d, 1H), 8.74 (s, 2H), 8.45 (d, 1H), 8.21 (d, 1H), 7.97 (dd, 1H)

[0158] <Synthesis Example 9>

[0159] Compound (17) was obtained in the same manner as in Synthesis Example 3, except that 3-amino-2-naphthamide (manufactured by Angine International Ltd.) was used instead of 2-aminobenzamide. Next, compound (18) was obtained in the same manner as in Synthesis Example 3, except that compound (17) was used instead of compound (6). The results of NMR measurement thereof are shown below. １HNMR (500MHz, DMSO-d6): 9.16 (d, 1H), 9.00 (s, 1H), 8.79 (d, 1H), 8.74 (q, 2H), 8.48 (d, 1H), 8.32 (dd, 1H), 8.22 (dd, 1H), 7.80 to 7.76 (m, 1H), 7.73 to 7.66 (m, 1H)

[0160] <Synthesis Example 10>

[0161] Compound (19) was obtained in the same manner as in Synthesis Example 3, except that 2-aminonicotinamide (manufactured by Combi-Block) was used instead of 2-aminobenzamide. Next, compound (20) was obtained in the same manner as in Synthesis Example 3, except that compound (19) was used instead of compound (6). The results of NMR measurement thereof are shown below. １ HNMR (500MHz, DMSO-d6): 9.19 (d, 1H), 9.07 (dd, 1H), 8.79 (d, 1H), 8.76 (s, 2H), 8.66 (dd, 1H), 7.69 (dd, 1H)

[0162] <Synthesis Example 11>

[0163] A mixture obtained by adding 2.0 g of compound (1) (manufactured by Tokyo Chemical Industry Co., Ltd.) and 1.5 g of aniline (manufactured by Tokyo Chemical Industry Co., Ltd.) (2.2 molar equivalents relative to compound (1)) to 15 mL of acetic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) was stirred at 125°C reflux for 8 hours. The mixture was then cooled to room temperature, methanol was added, and the precipitated mixture was filtered. After washing with methanol, pyridine was added and the mixture was stirred for 5 minutes. Next, after filtration and washing with methanol, the mixture was purified by sublimation to obtain compound (21) as a white solid. The results of NMR measurement are shown below. １ HNMR (500MHz, DMSO-d6): 8.73 (s, 4H), 7.58-7.45 (m, 10H)

[0164] <Synthesis Example 12>

[0165] A mixture obtained by adding 6.0 g of compound (1) (manufactured by Tokyo Chemical Industry Co., Ltd.), 6.1 g of isoquinoline (manufactured by Tokyo Chemical Industry Co., Ltd.) (2.1 molar equivalents relative to compound (1)), and 6.6 g of 4-aminobenzonitrile (manufactured by Tokyo Chemical Industry Co., Ltd.) (2.5 molar equivalents relative to compound (1)) to 90 mL of m-cresol (manufactured by Tokyo Chemical Industry Co., Ltd.) was stirred at 180°C for 8 hours. The mixture was then cooled to room temperature, methanol was added thereto, and the precipitate was filtered. After further washing with methanol, an aqueous potassium carbonate solution was added and the mixture was stirred for 5 minutes. Next, after filtration, the mixture was washed with water and methanol, and purified by sublimation to obtain compound (22) as a yellow solid. The results of NMR measurement of the resulting mixture are shown below. １ HNMR (500MHz, HFIP-d2): 8.93 (s, 4H), 8.77 (dm, 4H), 7.55 (dm, 4H)

[0166] <Synthesis Example 13>

[0167] Compound (23) was obtained in the same manner as in Synthesis Example 1, except that 2-aminobenzonitrile (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of aniline. Then, compound (24) was obtained in the same manner as in Synthesis Example 1, except that compound (23) was used instead of compound (2). The results of NMR measurement thereof are shown below. １ HNMR (500MHz, DMSO-d6): 9.18 (d, 1H), 8.88-8.73 (m, 3H), 8.29 (dd, 1H), 8.14 (dd, 1H) , 8.01-7.96 (m, 2H), 7.92 (d, 1H), 7.84 (dd, 1H), 7.79-7.74 (m, 1H), 7.72-7.67 (m, 1H)

[0168] <Synthesis Example 14>

[0169] A mixture obtained by adding 3.0 g of compound (7), 1.6 g of 2-aminobenzamide (manufactured by Tokyo Chemical Industry Co., Ltd.) (1.5 molar equivalents relative to compound (7)), and 1.8 mL of 1,8-diazabicyclo[5.4.0]-7-undecene (manufactured by Tokyo Chemical Industry Co., Ltd.) (1.5 molar equivalents relative to compound (7)) to 90 mL of N,N-dimethylformamide (manufactured by Tokyo Chemical Industry Co., Ltd.) was stirred at 150°C for 8 hours. The mixture was then cooled to room temperature, and the solvent was distilled off under reduced pressure. Acetone was added to the solid obtained by distilling off the solvent, and water was gradually added with stirring, and the precipitate was filtered. The precipitate was dissolved in chloroform, and then sodium sulfate was added and the mixture was allowed to stand for 30 minutes. Next, the sodium sulfate was filtered, and the solvent was distilled off under reduced pressure. Compound (25) was obtained as a reddish-brown solid through size exclusion chromatography using chloroform as an eluent. The results of NMR measurement are shown below. １ HNMR (500MHz, DMSO-d6): 9.16 (d, 1H), 8.77-8.71 (m, 3H), 8.29 (dd, 1H), 8.01-7.95 (m, 1H), 7.92 (s , 1H), 7.91 (d, 1H), 7.83 (dd, 1H), 7.79-7.75 (m, 2H), 7.62-7.57 (m, 1H), 7.53 (dd, 1H), 7.18 (s, 1H)

[0170] <Synthesis Example 15>

[0171] Compound (26) was obtained in the same manner as in Synthesis Example 3, except that 1,8-diaminonaphthalene (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of 2-aminobenzamide. Then, compound (27) was obtained in the same manner as in Synthesis Example 3, except that compound (26) was used instead of compound (6). The results of NMR measurement thereof are shown below. １ HNMR (500MHz, DMSO-d6): 9.35 (d, 1H), 9.19 (d, 1H), 9.35 (d, 1H), 9.12 (d, 1H), 8.49 (d, 1H), 7.87 (dd, 2H), 7.72 (dd, 1H), 7.63-7.55 (m, 2H)

[0172] [Preparation and Evaluation of Organic Thin Film and Photoelectric Conversion Element] In the following examples and comparative examples, organic thin films and photoelectric conversion elements were prepared using a vapor deposition machine, and measurements were made by applying current and voltage in the atmosphere. The prepared photoelectric conversion elements were placed in a measurement chamber, and measurements were made by applying current and voltage. A semiconductor parameter analyzer (manufactured by Keithley Instruments) was used for the measurements by applying current and voltage. Light irradiation was performed using a light source device (manufactured by Asahi Spectroscopy, product name (PVL-3300)) under conditions of an irradiation light wavelength of 550 nm and an irradiation light half-width of 20 nm. The light-dark ratio is the value obtained by dividing the current value when irradiated with light by the current value in a dark place.

[0173] Example 1 A photoelectric conversion layer of boron subphthalocyanine chloride (purified product of Sigma-Aldrich, purity >99%) was vacuum-formed to a thickness of 100 nm on an ITO transparent conductive glass (ITO manufactured by Geomatec Co., Ltd., thickness 100 nm). On top of this, tris(8-quinolinolato)aluminum (Alq ３ A sublimation refined product of (ITO) (manufactured by Tokyo Chemical Industry Co., Ltd.) was formed into a film with a thickness of 25 nm by resistance heating vacuum deposition, and then compound (3) was formed into a film with a thickness of 25 nm as auxiliary layer 2 by resistance heating vacuum deposition. Next, aluminum was formed as an electrode with a thickness of 100 nm by vacuum deposition on auxiliary layer 2 to obtain a photoelectric conversion element. For the obtained photoelectric conversion element, a voltage of 3 V was applied using ITO and aluminum as electrodes, and the current value in a dark place and the current value when irradiated with light were measured. The light-dark ratio was calculated from the measurement results. The results are shown in Table 1. The dark current value and light-dark ratio are shown as relative values ​​when the value in Comparative Example 1 described below is set to 1, and are evaluated based on the following criteria. However, a rating of "D" indicates that auxiliary layer 2 could not be stably formed, and therefore the dark current value and light-dark ratio could not be evaluated. <Dark current value> A: Less than 0.00005 B: 0.00005 or more and less than 1 C: 1 or more <Light / dark ratio> A: 10 or more B: More than 1 and less than 10 C: 1 or less

[0174] Example 2 A single-layer organic thin film and a photoelectric conversion element were prepared in the same manner as in Example 1, except that compound (5) was used instead of compound (3). The obtained photoelectric conversion element was evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0175] Example 3 A single-layer organic thin film and a photoelectric conversion element were prepared in the same manner as in Example 1, except that compound (10) was used instead of compound (3). The obtained photoelectric conversion element was evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0176] Comparative Example 1 A single-layer organic thin film and a photoelectric conversion element were prepared in the same manner as in Example 1, except that compound (21) was used instead of compound (3). The obtained photoelectric conversion element was evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0177] Comparative Example 2 A single-layer organic thin film and a photoelectric conversion element were prepared in the same manner as in Example 1, except that compound (22) was used instead of compound (3). The obtained photoelectric conversion element was evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0178] Comparative Example 3 A single-layer organic thin film and a photoelectric conversion element were prepared in the same manner as in Example 1, except that compound (24) was used instead of compound (3). The obtained photoelectric conversion element was evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0179] Comparative Example 4 A single-layer organic thin film and a photoelectric conversion element were prepared in the same manner as in Example 1, except that compound (25) was used instead of compound (3). The obtained photoelectric conversion element was evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0180]

[0181] Example 4 A single-layer organic thin film and a photoelectric conversion element were prepared in the same manner as in Example 1, except that compound (7) was used instead of compound (3). For the obtained photoelectric conversion element, a voltage of 3 V was applied using ITO and aluminum as electrodes, and the current value in a dark place and the current value when irradiated with light were measured. The light-dark ratio was calculated from the measurement results. The results are shown in Table 2. The dark current value and the light-dark ratio are shown as relative values ​​when the value in Comparative Example 5 described below is set to 1, and are evaluated based on the following criteria. <Dark current value> A: Less than 0.005 B: 0.005 or more and less than 1 C: 1 or more <Light-dark ratio> A: 10 or more B: More than 1 and less than 10 C: 1 or less

[0182] Example 5 A single-layer organic thin film and a photoelectric conversion element were prepared in the same manner as in Example 1, except that compound (9) was used instead of compound (3). The obtained photoelectric conversion element was evaluated in the same manner as in Example 4. The results are shown in Table 2.

[0183] Comparative Example 5 A single-layer organic thin film and a photoelectric conversion element were prepared in the same manner as in Example 1, except that compound (27) was used instead of compound (3). The obtained photoelectric conversion element was evaluated in the same manner as in Example 4. The results are shown in Table 2.

[0184]

[0185] From the results shown in Tables 1 and 2, it was found that the photoelectric conversion element of the present invention exhibits a low dark current value, and therefore has excellent leakage prevention properties, particularly in the dark. In particular, some examples exhibit a high light-to-dark ratio, and are therefore found to have even better leakage prevention properties. From the above, it was found that the compound of the present invention, such as compound (3), is suitable as a material for a photoelectric conversion element, particularly as a material contained in the electron transport layer and hole blocking layer of a photoelectric conversion element. It was also found that the compound of the present invention, such as compound (3), is suitable as a material contained in an imaging element.

[0186] This application is based on a Japanese patent application (Patent Application No. 2023-216354) filed on December 22, 2023, the contents of which are incorporated herein by reference.

[0187] Photoelectric conversion elements, imaging elements, etc. containing the above-mentioned compound (I) have excellent leak prevention properties. Therefore, the compound, photoelectric conversion element material, organic thin film, photoelectric conversion element, and imaging element of the present invention have industrial applicability in fields where such properties are required. Specifically, as solid-state imaging elements, they have industrial applicability in imaging elements in security cameras, vehicle-mounted cameras, unmanned aerial vehicle cameras, agricultural cameras, industrial cameras, medical cameras such as endoscopic cameras, game console cameras, digital still cameras, digital video cameras, mobile phone cameras, and cameras for mobile devices other than those mentioned above; image reading elements in facsimiles, scanners, copiers, etc.; and optical sensors in bio- and chemical sensors, etc. In addition, as displays using electroluminescence, they have industrial applicability in television monitors, touch monitors, digital signage, wearable displays, electronic paper, head-up displays for mobility applications, etc.

[0188] 100, 200... photoelectric conversion element, 101... substrate, 102... lower electrode, 103... first auxiliary layer, 104... photoelectric conversion layer, 105... second auxiliary layer, 106... upper electrode, 107... third auxiliary layer, 110... photoelectric conversion film.

Claims

1. A compound represented by the following formula (I): (X1 is an oxygen atom or NR ３ And X ２ is a nitrogen atom or CR ４ And X ３ is a nitrogen atom or CR ５ n is an integer of 0 to 3; R １ , R ２ , R ３ , R ４ and R ５ are each independently selected from the group consisting of a hydrogen atom, a halogen atom, a hydroxy group, a thiol group, an amino group, a cyano group, a carboxy group, a nitro group, and an optionally substituted linear, branched or cyclic alkyl group, a thioalkyl group, a thioaryl group, an arylsulfonyl group, an aryloxy group, an alkylsulfonyl group, an alkylamino group, an arylamino group, an alkoxy group, an acylamino group, an acyloxy group, an aryl group, a carboxamide group, a carboalkoxy group, a carboaryloxy group, an acyl group, and a monovalent heterocyclic group; １ , R ２ , R ４ and R ５ may be a part of a fused ring, and the fused ring may contain one or more atoms other than carbon atoms. ).

2. R ３ is represented by the following formula (IV): (R ６ , R ７ , R ８ , R ９ and R １０ are each independently selected from the group consisting of a hydrogen atom, a halogen atom, a hydroxy group, a thiol group, an amino group, a cyano group, a carboxy group, a nitro group, and an optionally substituted linear, branched or cyclic alkyl group, a thioalkyl group, a thioaryl group, an arylsulfonyl group, an aryloxy group, an alkylsulfonyl group, an alkylamino group, an arylamino group, an alkoxy group, an acylamino group, an acyloxy group, an aryl group, a carboxamide group, a carboalkoxy group, a carboaryloxy group, an acyl group, and a monovalent heterocyclic group; ６ , R ７ , R ８ , R ９ and R 1０ may be part of a fused ring, and the fused ring may contain one or more atoms other than carbon atoms.

3. The compound according to claim 1 or 2, wherein the energy level of the lowest unoccupied molecular orbital obtained by density functional theory is −6.00 eV or more and −3.50 eV or less.

4. The compound according to claim 1 or 2, which is a material for a photoelectric conversion element.

5. The following formula (I): (X1 is an oxygen atom or NR ３ And X ２ is a nitrogen atom or CR ４ And X ３ is a nitrogen atom or CR ５ n is an integer of 0 to 3; R １ , R ２ , R ３ , R ４ and R ５ are each independently selected from the group consisting of a hydrogen atom, a halogen atom, a hydroxy group, a thiol group, an amino group, a cyano group, a carboxy group, a nitro group, and an optionally substituted linear, branched or cyclic alkyl group, a thioalkyl group, a thioaryl group, an arylsulfonyl group, an aryloxy group, an alkylsulfonyl group, an alkylamino group, an arylamino group, an alkoxy group, an acylamino group, an acyloxy group, an aryl group, a carboxamide group, a carboalkoxy group, a carboaryloxy group, an acyl group, and a monovalent heterocyclic group; １ , R ２ , R ４ and R ５ may be a part of a fused ring, and the fused ring may contain one or more atoms other than carbon atoms.

6. A photoelectric conversion element comprising a first electrode film, a second electrode film, and a photoelectric conversion film located between the first electrode film and the second electrode film, wherein the photoelectric conversion film contains the material for photoelectric conversion elements described in claim 4.

7. A photoelectric conversion element comprising a first electrode film, a second electrode film, and a photoelectric conversion film located between the first electrode film and the second electrode film, wherein the photoelectric conversion film includes the organic thin film described in claim 5.

8. The photoelectric conversion element according to claim 7, wherein the photoelectric conversion film includes a photoelectric conversion layer and an auxiliary layer, and the auxiliary layer consists of only the organic thin film or consists of a plurality of films including the organic thin film.

9. A photoelectric conversion element comprising a first electrode film, a second electrode film, and a photoelectric conversion film located between the first electrode film and the second electrode film, the photoelectric conversion film comprising a photoelectric conversion layer and two auxiliary layers located between the photoelectric conversion layer and the second electrode film, and one of the two auxiliary layers closer to the second electrode film includes the organic thin film described in claim 5.

10. An imaging device comprising the photoelectric conversion element according to claim 7.

11. The imaging device according to claim 10, which is formed by stacking two or more of said photoelectric conversion elements.

12. An imaging device comprising a plurality of photoelectric conversion elements according to claim 7 arranged in an array.

13. An optical sensor comprising the imaging element according to claim 10.

14. A solid-state imaging device comprising the imaging element according to claim 10.

Images