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

Abstract

A compound represented by formula (I) (R1 and R2 are hydrogen atoms, and R3-R7 are each independently a hydrogen atom, a halogen atom, a linear, branched or cyclic alkyl group, or the like).

Description

Technical Field

[0001] This disclosure relates to compounds, organic thin films, photoelectric conversion elements, imaging elements, light sensors, and solid-state imaging devices. Background Technology

[0002] Previously, techniques for photoelectric conversion of visible light into electrical signals were known, and these techniques were used, for example, in imaging elements. Such imaging elements are found in solid-state imaging devices such as CCD (Charge Coupled Device) image sensors and CMOS (Complementary Metal Oxide Semiconductor) image sensors. In recent years, with the continuous miniaturization of pixel sizes in solid-state imaging devices, organic photoelectric conversion films have been researched to address this issue. For example, Patent Documents 1 and 2 disclose organic photoelectric conversion films composed of phthalocyanine and imide compounds.

[0003] Furthermore, solid-state imaging devices require a balance between high spectral selectivity and a high signal-to-noise ratio (S / N ratio). Therefore, it is desirable for solid-state imaging devices to possess high external quantum efficiency (EQE) and low dark current characteristics. To achieve this balance, methods are known for configuring electron transport layers and hole blocking layers, and / or hole transport layers and electron blocking layers, between the photoelectric conversion section and the electrode section. Here, electron transport layers, hole blocking layers, and electron blocking layers, which are widely used in the field of organic electronic devices, are configured in the film constituting the device at the interface between the electrode or a conductive film and other films. These layers respectively function to control the reverse migration of holes or electrons and adjust for unnecessary leakage of holes or electrons. For example, Patent Document 3 shows an example of using 1,4,5,8-naphthalene-tetracarboxylic dianhydride (NTCDA) as a material used in such layers.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2018-32754

[0007] Patent Document 2: Japanese Patent Publication No. 2018-512423

[0008] Patent Document 3: Japanese Patent Publication No. 2014-506736 Summary of the Invention

[0009] The problem the invention aims to solve

[0010] However, existing hole blocking layers and electron blocking layers, represented by those disclosed in Patent Document 3, have room for further improvement in suppressing leakage current in the dark and having high wavelength selectivity.

[0011] The object of the present invention is to provide: compounds and photoelectric conversion element materials that are capable of suppressing leakage current in the dark, particularly useful for photoelectric conversion elements, as well as organic thin films containing the compounds, photoelectric conversion elements, imaging elements, light sensors, and solid-state imaging devices.

[0012] Solution for solving the problem

[0013] The present invention is described below. [1]

[0015] The compound represented by the following formula (I),

[0016]

[0017] (R1 and R2 are hydrogen atoms, and R3, R4, R5, R6, and R7 are each independently selected from the group consisting of hydrogen atoms, halogen atoms, hydroxyl groups, mercapto groups, amino groups, cyano groups, carboxyl groups, nitro groups, 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, carboxylamide groups, alkoxycarbonyl groups, aryloxycarbonyl groups, acyl groups, and monovalent heterocyclic groups, and any adjacent R3, R4, R5, and R6 are optionally part of a fused aliphatic ring or a fused aromatic ring. The aforementioned fused aliphatic ring and fused aromatic ring optionally contain one or more atoms other than carbon.) [2]

[0019] The compound represented by formula (II) below,

[0020]

[0021] (R1 and R2 are hydrogen atoms, R8 is selected from the group consisting of hydrogen atoms, halogen atoms, hydroxyl groups, mercapto groups, amino groups, carboxyl groups, nitro groups, and optionally substituted straight-chain, branched, or cyclic alkyl groups, thioalkyl groups, thioaryl groups, aryloxy groups, alkylamino groups, arylamino groups, alkoxy groups, acylamino groups, acyloxy groups, aryl groups, carboxylamide groups, alkoxycarbonyl groups, aryloxycarbonyl groups, acyl groups, and monovalent heterocyclic groups, R7, R9, R...) 10 and R 11Each of the following groups is independently selected from the group consisting of hydrogen atom, halogen atom, hydroxyl group, mercapto group, amino group, cyano group, carboxyl group, nitro group, and optionally substituted straight-chain, branched, or cyclic alkyl, thioalkyl, thioaryl, arylsulfonyl, aryloxy, alkylsulfonyl, alkylamino, arylamino, alkoxy, acylamino, acyloxy, aryl, carboxylamide, alkoxycarbonyl, aryloxycarbonyl, acyl, and monovalent heterocyclic groups, and any adjacent R8, R9, R 10 and R 11 Optionally, it is part of a fused aliphatic ring or a fused aromatic ring. The aforementioned fused aliphatic ring and fused aromatic ring optionally contain one or more atoms other than carbon. [3]

[0023] According to the compounds described in [1] or [2], the lowest unoccupied molecular orbital energy level obtained by density functional theory is above -6.00 eV and below -3.50 eV. [4]

[0025] According to any one of [1] to [3], the energy difference between the lowest unoccupied molecular orbital energy level and the highest occupied molecular orbital energy level obtained by density functional theory is greater than 3.00 eV and less than 4.00 eV. [5]

[0027] The compound according to any one of [1] to [4] is a material for photoelectric conversion elements. [6]

[0029] An organic thin film comprising any one of the compounds described in [1] to [5]. [7]

[0031] According to [6], the organic thin film has a maximum absorption wavelength of light absorption band below 450 nm. [8]

[0033] A photoelectric conversion element includes a first electrode film, a second electrode film, and a photoelectric conversion film located between the first electrode film and the second electrode film.

[0034] The aforementioned photoelectric conversion film includes the material for photoelectric conversion elements described in [5]. [9]

[0036] A photoelectric conversion element includes a first electrode film, a second electrode film, and a photoelectric conversion film located between the first electrode film and the second electrode film.

[0037] The aforementioned photoelectric conversion film includes the organic thin film described in [6] or [7].

[10]

[0039] According to the photoelectric conversion element described in [8] or [9], wherein,

[0040] The aforementioned photoelectric conversion film includes a photoelectric conversion layer and an auxiliary layer.

[0041] The aforementioned auxiliary layer is composed solely of the aforementioned organic thin film, or is composed of multiple films containing the aforementioned organic thin film.

[11]

[0043] A camera element comprising any one of the photoelectric conversion elements described in [8] to

[10] .

[12]

[0045] The imaging element described in

[11] is formed by stacking two or more of the aforementioned photoelectric conversion elements.

[13]

[0047] A camera element is formed by arranging a plurality of photoelectric conversion elements as described in any one of [8] to

[10] in an array.

[14]

[0049] A light sensor having an imaging element as described in any one of

[11] to

[13] .

[15]

[0051] A solid-state camera device comprising any one of the following:

[11] to

[13]

[0052] The effects of the invention

[0053] According to the present invention, it is possible to provide: compounds and photoelectric conversion element materials that are capable of suppressing leakage current in the dark, particularly useful for photoelectric conversion elements, as well as organic thin films containing the compounds, photoelectric conversion elements, imaging elements, light sensors, and solid-state imaging devices. Attached Figure Description

[0054] Figure 1 This is a cross-sectional schematic diagram that partially illustrates an example of the photoelectric conversion element of the present invention.

[0055] Figure 2 This is a cross-sectional schematic diagram that partially illustrates another example of the photoelectric conversion element of the present invention. Detailed Implementation

[0056] Hereinafter, the embodiments for carrying out the present invention (hereinafter referred to as "this embodiment") will be described in detail with reference to the accompanying drawings, but the present invention is not limited to the following embodiment. The present invention can be modified in various ways without departing from its spirit. It should be noted that in the drawings, the same reference numerals are used to label the same elements, and repeated descriptions are omitted. Furthermore, unless otherwise specified, positional relationships such as up, down, left, and right are based on the positional relationships shown in the drawings. Moreover, the scale of the drawings is not limited to the scale shown in the illustrations.

[0057] In this specification, fluorine (F), chlorine (Cl), bromine (Br) and iodine (I) can be cited as halogen atoms.

[0058] In this specification, the straight-chain alkyl group can be a straight-chain alkyl group with 1 to 12 carbon atoms, such as methyl (Me), ethyl (Et), n-propyl (n-Pr), n-butyl (n-Bu), n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, and n-dodecyl.

[0059] In this specification, the branched alkyl group can be a branched alkyl group having 1 to 12 carbon atoms, such as isopropyl (i-Pr), sec-butyl (s-Bu), tert-butyl (t-Bu), isopentyl, sec-pentyl, 3-pentyl, neopentyl, isohexyl, isooctyl, isononyl, isodecyl, and isododecyl. Furthermore, the straight-chain or branched alkyl group may have substituents. Examples of substituents include halogen atoms such as fluorine atoms, monovalent groups having aromatic rings such as benzyl, naphthyl, and phenoxy, monovalent groups having heteroatoms such as alkoxy, aminoalkyl, and thioalkyl, monovalent groups having heterocycles such as pyridyl, hydroxyl, carboxyl, amino, and mercapto.

[0060] In this specification, the cyclic alkyl group can be a cyclic alkyl group having 3 to 10 carbon atoms, such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl. Furthermore, the cyclic alkyl group may have heteroatoms such as nitrogen, oxygen, and sulfur atoms in its ring. Examples of such cyclic alkyl groups include pyrrolidinyl, oxazolyl, pyrazolyl, thiazolyl, imidazolyl, dioxofuranyl, tetrahydrofuranyl, tetrahydrothiophene, piperazine, dioxacyclohexyl, and morpholinyl. Moreover, monovalent groups such as hydroxyl, carboxyl, amino, and mercapto groups can be bonded to the cyclic alkyl group.

[0061] In this specification, thioalkyl (-SR; hereinafter, R represents alkyl) and thioaryl (-SAr; hereinafter, Ar represents aryl) can be thioalkyl groups having 1 to 12 carbon atoms in the alkyl group and thioaryl groups having 6 to 16 carbon atoms in the aryl group. Furthermore, thioalkyl and thioaryl groups may also have substituents such as amino, hydroxyl, halogen atom, alkoxy, or thioalkyl groups. Examples of such thioalkyl and thioaryl groups include methylthio, ethylthio, phenylthio, toluenethio, aminophenylthio, hydroxyphenylthio, fluorophenylthio, dimethylphenylthio, and methylthiophenylthio.

[0062] In this specification, the aryl sulfonyl group (-SO2-Ar) can be an aryl sulfonyl group with 6 to 16 carbon atoms in the aryl group, such as phenyl sulfonyl, toluene sulfonyl, dimethylbenzene sulfonyl, mesitylene sulfonyl, octylbenzene sulfonyl and naphthalene sulfonyl.

[0063] In this specification, the aryloxy group (-O-Ar) can be an aryloxy group having 6 to 16 carbon atoms. Additionally, the aryloxy group may also have substituents such as a cyano group, a halogen atom such as a fluorine atom, an alkoxy group such as a hydroxyl group, a methoxy group, an amino group, an alkylamino group, a mercapto group, or an aryloxy group. Examples of such aryloxy groups include phenoxy, cyanophenoxy, methyl cyanophenoxy, dimethyl cyanophenoxy, fluorocyanophenoxy, dicyanophenoxy, methoxycyanophenoxy, tricyanophenoxy, cyanonaphthoxy, dicyanonaphthoxy, 2-methylphenoxy, 3-methylphenoxy, 4-methylphenoxy, fluoromethylphenoxy, dimethylphenoxy, 3-hydroxyphenoxy, fluoro-3-hydroxyphenoxy, 2-hydroxyphenoxy, fluoro-2-hydroxyphenoxy, methoxyphenoxy, ethoxyphenoxy, fluorophenoxy, perfluorophenoxy, dimethoxyphenoxy, aminophenoxy, N,N-dimethylaminophenoxy, thiophenoxy, (trifluoromethyl)phenoxy, naphthoxy, methoxynaphthoxy, fluoronaphthoxy, and phenoxyphenoxy.

[0064] In this specification, the alkyl sulfonyl group (-SO2-R) can be an alkyl sulfonyl group with 1 to 12 carbon atoms, such as methanesulfonyl, ethylsulfonyl and n-butylsulfonyl.

[0065] In this specification, the alkylamino group (here, the alkylamino group is -NHR or -NR2, and the two Rs may be the same or different) can be an alkylamino group with 1 to 12 carbon atoms, such as methylamino, ethylamino, n-propylamino, n-butylamino, n-pentylamino, n-hexylamino, n-heptylamino, n-octylamino, n-nonylamino, n-decylamino, n-dodecylamino, isopropylamino, sec-butylamino, tert-butylamino, isopentylamino, sec-pentylamino, 3-pentylamino, neopentylamino, isohexylamino, isoheptylamino, isooctylamino, isononylamino, isodecylamino, isododecylamino, dimethylamino, diethylamino, diisopropylamino, and isopropylethylamino.

[0066] In this specification, the arylamino group (here, the arylamino group is -NHAr or -NAr2, and the two Ar atoms can be the same or different) can be an arylamino group with 6 to 16 carbon atoms, such as: aniline, toluidine, dimethylaniline, isopropylaniline, tert-butylaniline, fluoroaniline, trifluoromethylaniline, bis(trifluoromethyl)aniline, pyridylamino, methylpyridylamino, fluoropyridylamino, pyrimidinylamino, and biphenylamino.

[0067] In this specification, the alkoxy group (-OR) can be an alkoxy group having 1 to 12 carbon atoms, such as methoxy, ethoxy, n-propoxy, n-butoxy, n-pentoxy, n-hexoxy, n-heptoxy, n-octoxy, n-nonoxy, n-decoxy, n-dodecyloxy, isopropoxy, sec-butoxy, tert-butoxy, isopentoxy, sec-pentoxy, 3-pentoxy, neopentoxy, isohexoxy, isooctoxy, isononoxy, isodecanoxy, and isodecanoxy.

[0068] 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 also have halogen atoms such as fluorine atoms, substituents such as alkoxy groups and cyano groups. Examples of such acylamino groups include acetylamino, propionylamino, benzoylamino, methylbenzoylamino, dimethylbenzoylamino, methoxybenzoylamino, cyanobenzoylamino, and bis(trifluoromethyl)benzoylamino.

[0069] In this specification, the acyloxy group (-O-COR or -O-COAr) can be an alkyl group having 1 to 12 carbon atoms or an aryl group having 6 to 16 carbon atoms. The acyloxy group may also have a halogen atom such as a fluorine atom, a cyano group, and optionally a substituted alkyl group, and may also have a heteroatom such as a nitrogen atom within the aromatic ring. Examples of such acyloxy groups include benzoyloxy, toluoxy, dimethylbenzoyloxy, cyanobenzoyloxy, fluorobenzoyloxy, bis(trifluoromethyl)benzoyloxy, pyridinecarboxyl, and methylpyridinecarboxyl.

[0070] In this specification, the aryl group (-Ar) can be an aryl group having 6 to 16 carbon atoms. The aryl group may also have substituents such as amino, hydroxyl, mercapto, halogen atoms (e.g., fluorine), nitro, cyano, and optionally substituted alkyl groups, and may also have heteroatoms such as nitrogen atoms within the aromatic ring. Examples of such aryl groups include phenyl, methylphenyl, ethylphenyl, dimethylphenyl, trimethylphenyl, methoxyphenyl, dimethoxyphenyl, trimethoxyphenyl, methoxymethylphenyl, aminophenyl, diaminophenyl, aminomethylphenyl, hydroxyphenyl, dihydroxyphenyl, hydroxymethylphenyl, hydroxyethylphenyl, phenylthio, methylphenylthio, dithiophenyl, fluorophenyl, fluoromethylphenyl, trifluoromethylphenyl, perfluorophenyl, fluoro(trifluoromethyl)phenyl, bis(trifluoromethyl)phenyl, cyanophenyl, methylcyanophenyl, dimethylcyanophenyl, dicyanophenyl, methoxycyanophenyl, tricyanophenyl, dicyanophenyl, etc. Methylcyanopyridyl, (trifluoromethyl)cyanopyridyl, dimethylcyanopyridyl, dicyanopyridyl, methoxycyanopyridyl, tricyanopyridyl, cyanopyridyl, naphthyl, nitrophenyl, dinitrophenyl, nitrofluorophenyl, methylnaphthyl, ethylnaphthyl, dimethylnaphthyl, trimethylnaphthyl, methoxynaphthyl, dimethoxynaphthyl, trimethoxynaphthyl, aminonaphthyl, diaminonaphthyl, aminomethylnaphthyl, hydroxynaphthyl, dihydroxynaphthyl, hydroxymethylnaphthyl, hydroxyethylnaphthyl, naphthio, methylnaphthio, naphthiodithio, fluoronaphthyl, trifluoromethylnaphthyl, perfluoronaphthyl, di(trifluoromethyl)naphthyl, biphenyl, cyanobiphenyl.

[0071] In this specification, the carboxyl amide group (here, the carboxyl amide group is -CO-NH2, -CO-NHR, -CONR2, the two Rs can be the same or different, and can be -CONHAr or -CONAr2, the two Ars can be the same or different) can be a carboxyl amide group with 1 to 12 carbon atoms in the alkyl group or 6 to 16 carbon atoms in the aryl group, for example, dimethyl carboxyl amide group and diphenyl carboxyl amide group can be mentioned.

[0072] In this specification, the alkoxycarbonyl or aryloxycarbonyl (-COOR or -COOAr) can be an alkoxycarbonyl or aryloxycarbonyl with 1 to 12 carbon atoms in the alkyl group or 6 to 16 carbon atoms in the aryl group, for example, methoxycarbonyl or phenoxycarbonyl.

[0073] In this specification, the monovalent heterocyclic group can be a monovalent heterocyclic group with 3 to 14 carbon atoms, such as furanyl, thiophene, pyrrole, pyrazolyl, imidazole, triazolyl, oxazolyl, dioxazolyl, isoxazolyl, oxadiazolyl, thiazolyl, isothiazolyl, thiazolyl, isothiazolyl, thiadiazolyl, triazolyl, indole, indolyl, indololinyl, indoleazinyl, indazole, pseudoindolyl, and benzene. The following are listed: furanyl, benzothiopheneyl, carbazoyl, dibenzofuranyl, dibenzothiopheneyl, pyridyl, diazinyl, oxazinyl, thiazinyl, dioxinyl, dithiopheneyl, triazinyl, pyrimidinyl, pyrazinyl, quinolinyl, isoquinolinyl, cyclolinyl, phthalazinyl, quinazolinyl, naphridinyl, purinyl, pteridinyl, acridineyl, phenanthridineyl, phenanthroxazinyl, xanthonyl, phenoxazinyl, thiaanthrylyl, morpholinyl, and phenazinyl.

[0074] (Compound (I) and Compound (II))

[0075] One embodiment of the compound is represented by the following formula (I):

[0076]

[0077] (Hereinafter, this compound will also be referred to as "Compound (I)"). Here, R1 and R2 are hydrogen atoms, and R3, R4, R5, R6, and R7 are each independently selected from the group consisting of hydrogen atoms, halogen atoms, hydroxyl groups, mercapto groups, amino groups, cyano groups, carboxyl groups, nitro groups, 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, carboxylamide groups, alkoxycarbonyl groups, aryloxycarbonyl groups, acyl groups, and monovalent heterocyclic groups, and any adjacent R3, R4, R5, and R6 are optionally part of a fused aliphatic ring or a fused aromatic ring. The aforementioned fused aliphatic ring and fused aromatic ring optionally contain one or more atoms other than carbon.

[0078] One embodiment of the compound is represented by the following formula (II):

[0079]

[0080] (Hereinafter, this compound will also be referred to as "Compound (II)"). Here, R1 and R2 are hydrogen atoms, R8 is selected from the group consisting of hydrogen atoms, halogen atoms, hydroxyl groups, mercapto groups, amino groups, carboxyl groups, nitro groups, and optionally substituted straight-chain, branched, or cyclic alkyl, thioalkyl, thioaryl, aryloxy, alkylamino, arylamino, alkoxy, acylamino, acyloxy, aryl, carboxylamide, alkoxycarbonyl, aryloxycarbonyl, acyl, and monovalent heterocyclic groups, R7, R9, R 10 and R 11 Each of the following groups is independently selected from the group consisting of hydrogen atom, halogen atom, hydroxyl group, mercapto group, amino group, cyano group, carboxyl group, nitro group, and optionally substituted straight-chain, branched, or cyclic alkyl, thioalkyl, thioaryl, arylsulfonyl, aryloxy, alkylsulfonyl, alkylamino, arylamino, alkoxy, acylamino, acyloxy, aryl, carboxylamide, alkoxycarbonyl, aryloxycarbonyl, acyl, and monovalent heterocyclic groups, and any adjacent R8, R9, R 10 and R 11 It may optionally be part of a fused aliphatic ring or a fused aromatic ring. The aforementioned fused aliphatic ring and fused aromatic ring may optionally contain one or more atoms other than carbon.

[0081] Such compounds (I) and (II) can suppress leakage current in the dark, and in particular exhibit excellent properties as materials for photoelectric conversion elements. The main reason for this is not yet clear, but the inventors have considered it as follows. However, the main reason is not limited to the following. That is, by having two sulfonyl groups, the energy level of the lowest unoccupied molecular orbital of compound (I) or compound (II) becomes an appropriate range, and leakage current in the dark can be suppressed.

[0082] In formula (I), from the viewpoint of more effectively and reliably exerting the effects of the present invention, R3, R4, R5 and R6 are preferably each independently selected from the group consisting of hydrogen atom, halogen atom, hydroxyl, mercapto, amino, cyano, carboxyl, nitro, and optionally substituted straight-chain, branched or cyclic alkyl, thioalkyl, thioaryl, arylsulfonyl, aryloxy, alkylsulfonyl, alkylamino, arylamino, alkoxy, acylamino, acyloxy, aryl, carboxylamide, alkoxycarbonyl, aryloxycarbonyl, acyl and monovalent heterocyclic groups, more preferably from the group consisting of hydrogen atom, halogen atom, nitro, cyano, and optionally substituted straight-chain, branched or cyclic alkyl and aryl groups, and particularly preferably from the group consisting of hydrogen atom, halogen atom, nitro, cyano, and optionally substituted alkyl and aryl groups.

[0083] In formula (I), R3, R4, R5, and R6 may be the same or different. From the viewpoint of more effectively and reliably exerting the effects of the present invention, it is preferable that at least two of R3, R4, R5, and R6 are the same, more preferably that at least three of R3, R4, R5, and R6 are the same, and particularly preferably that R3, R4, R5, and R6 are the same.

[0084] In formula (II), from the viewpoint of more effectively and reliably exerting the effects of the present invention, R8 is preferably selected from the group consisting of free hydrogen atom, halogen atom, hydroxyl group, mercapto group, amino group, carboxyl group, nitro group, and optionally substituted straight-chain, branched or cyclic alkyl group, thioalkyl group, thioaryl group, aryloxy group, alkylamino group, arylamino group, alkoxy group, acylamino group, acyloxy group, aryl group, carboxylamide group, alkoxycarbonyl group, aryloxycarbonyl group, acyl group and monovalent heterocyclic group, more preferably selected from the group consisting of free hydrogen atom, halogen atom, nitro group, cyano group, and optionally substituted straight-chain, branched or cyclic alkyl group and aryl group, particularly preferably selected from the group consisting of free hydrogen atom, halogen atom, nitro group, cyano group, and optionally substituted alkyl group and aryl group.

[0085] In formula (II), from the viewpoint of more effectively and reliably exerting the effects of the present invention, R9, R 10 and R 11 Preferably, the group consisting of a free hydrogen atom, halogen atom, hydroxyl group, mercapto group, amino group, cyano group, carboxyl group, nitro group, and optionally substituted straight-chain, branched or cyclic alkyl group, thioalkyl group, thioaryl group, arylsulfonyl group, aryloxy group, alkylsulfonyl group, alkylamino group, arylamino group, alkoxy group, acylamino group, acyloxy group, aryl group, carboxylamide group, alkoxycarbonyl group, aryloxycarbonyl group, acyl group and monovalent heterocyclic group is preferred. More preferably, the group consisting of a free hydrogen atom, halogen atom, nitro group, cyano group, and optionally substituted straight-chain, branched or cyclic alkyl group, aryl group, alkylsulfonyl group and arylsulfonyl group is preferred. Particularly preferred, the group consisting of a free hydrogen atom, halogen atom, nitro group, cyano group, and optionally substituted alkyl group, aryl group, alkylsulfonyl group and arylsulfonyl group is preferred.

[0086] In equation (II), R9, R 10 and R 11 They can be the same or different. From the viewpoint of more effectively and reliably exerting the effects of the present invention, it is preferable to select from R9 and R... 10 and R 11 At least two of them are the same, with R9 and R being particularly preferred. 10 and R 11 same.

[0087] In equation (II), R8 and R9, R 10 and R 11They can be the same or different. From the viewpoint of more effectively and reliably exerting the effects of the present invention, it is preferable to select from R8, R9, and R... 10 and R 11 At least two of them are the same, preferably selected from R8, R9, and R 10 and R 11 At least three of them are the same, with R8, R9, and R being particularly preferred. 10 and R 11 same.

[0088] In formulas (I) and (II), from the viewpoint of more effectively and reliably exerting the effects of the present invention, R7 is preferably selected from the group consisting of free hydrogen atoms, halogen atoms, nitro, cyano, and optionally substituted straight-chain, branched or cyclic alkyl, aryl and monovalent heterocyclic groups; more preferably from the group consisting of free hydrogen atoms, halogen atoms, nitro, cyano, and optionally substituted straight-chain, branched or cyclic alkyl and aryl groups; and particularly preferably from the group consisting of free hydrogen atoms, halogen atoms, nitro, cyano, and optionally substituted alkyl and aryl groups.

[0089] Hereinafter, specific examples of R7 in formulas (I) and (II) are shown. Here, "Ph" represents phenyl. From the viewpoint of more effectively and reliably exerting the effects of the present invention, R7 is preferably selected from the group consisting of free methyl, perfluoromethyl and phenyl, more preferably methyl or perfluoromethyl, and even more preferably perfluoromethyl.

[0090]

[0091] The following shows a preferred combination of R3, R4, R5 and R6 in compound (I), but it is also preferred that R3, R4, R5 and R6 are all hydrogen atoms.

[0092]

[0093]

[0094]

[0095]

[0096]

[0097] The following shows R8, R9, and R in compound (II). 10 and R 11 The preferred combination is R8, R9, and R9. 10 and R 11 All are hydrogen atoms.

[0098]

[0099]

[0100]

[0101]

[0102]

[0103]

[0104] The following are specific examples of compound (I). However, compound (I) is not limited to these.

[0105]

[0106] The following are specific examples of compound (II). However, compound (II) is not limited to these.

[0107]

[0108] From the viewpoint of more effectively and reliably exerting the effects of the present invention, the energy levels of the lowest unoccupied molecular orbitals (LUMOs) of compounds (I) and (II) of this embodiment (hereinafter referred to as compounds (I) and (II)) obtained by density functional theory are preferably -6.00 eV or higher and -3.50 eV or lower, more preferably -5.50 eV or higher and -3.60 eV or lower. For compounds (I) and (II) of this embodiment, the energy levels of the lowest unoccupied molecular orbitals of compounds (I) and (II) can be obtained by structural optimization using molecular simulations using density functional theory (e.g., molecular simulations using Gaussian, a quantum chemical calculation program manufactured by Gaussian Corporation). In addition, the energy levels of the lowest unoccupied molecular orbitals of compounds (I) and (II) of this embodiment obtained by density functional theory can be obtained by changing R3~R 11 To adjust. In addition, from the viewpoint of more effectively and reliably exerting the effects of the present invention, the structures of compounds (I) and (II) are particularly preferred among compounds with a LUMO of -3.50 eV or less.

[0109] The energy difference (eV) between the lowest unoccupied molecular orbital (HOMO) and the highest occupied molecular orbital (HOMO) of compounds (I) and (II) in this embodiment, obtained by density functional theory ([HOMO energy level] - [lowest unoccupied molecular orbital energy level]), is preferably 3.00 eV or more and 4.00 eV or less, more preferably 3.20 eV or more and 3.80 eV or less. By keeping the energy level difference within the above range, there is a tendency to reduce leakage current in the dark when used as a material for photoelectric conversion elements.

[0110] The molecular weights of compounds (I) and (II) in this embodiment are preferably 300 or more, more preferably 350 or more, and even more preferably 400 or more. If the molecular weight is 300 or more, changes in physical properties caused by molecular thermal motion that may occur during heating operations or high-temperature operating environments in the manufacturing process of organic thin films using compounds (I) and (II) can be further suppressed. Furthermore, particularly when compounds (I) and (II) are formed by vacuum evaporation, the molecular weights of compounds (I) and (II) are preferably 1000 or less, more preferably 950 or less, and even more preferably 900 or less. If the molecular weight is 1000 or less, the heat energy required for sublimation during the formation of organic thin films of compounds (I) and (II) by vacuum evaporation can be suppressed even further. Thus, compounds (I) and (II) can form good thin films without thermal degradation. However, when thin films are formed by solution coating, such problems are less likely to occur, therefore the molecular weights of compounds (I) and (II) can be greater than 1000.

[0111] Compounds (I) and (II) can be synthesized, for example, by the following reaction scheme.

[0112]

[0113] More specifically, for example, by imidizing a commercially available compound (A) using compound (B) or compound (C), compound (I) or (II) can be obtained. More specifically, imidization can be performed, for example, by the method described in Organic Electronics, 63,250 (2018). Alternatively, the desired R3~R can be introduced... 11 The reaction can proceed with compound (B) or compound (C), or the desired R3~R can be introduced after imidization. 11 .

[0114] Compounds (I) and (II) of this embodiment are obtained, for example, by synthesis as described above. In the product obtained by synthesis (100% by mass), the content of compounds (I) and (II) is preferably 90% by mass or more, more preferably 93% by mass or more, and even more preferably 97% by mass or more. By ensuring that the content of compounds (I) and (II) is 90% by mass or more, when compounds (I) and (II) are used in photoelectric conversion elements or imaging elements, it is possible to more effectively and reliably prevent charge carriers from being captured by impurity energy levels generated by undesirable impurities. As a result, recombination of charge carriers can be suppressed, resulting in photoelectric conversion elements or imaging elements with superior performance. The content can be determined by methods such as liquid chromatography, gas chromatography, and elemental analysis, as long as they are known methods.

[0115] (Materials for photoelectric conversion elements)

[0116] As a photoelectric conversion element material, more specifically, it can be used as a material contained in each layer of the photoelectric conversion element described later. From the viewpoint of more effectively and reliably exerting the effects of the present invention, compounds (I) and (II) are preferably contained in the photoelectric conversion film, more preferably in the auxiliary layer, and particularly preferably in at least one of the electron transport layer and the hole blocking layer.

[0117] Furthermore, compounds (I) and (II) of this embodiment can be used directly as photosensitive materials, or they can be mixed with other materials to form a photosensitive composition. The content of compounds (I) and (II) in the photosensitive composition can be 50% by mass or more relative to the total amount of the composition. Alternatively, the content can be 95% by mass or less, 90% by mass or less, or 80% by mass or less. There are no particular limitations on materials other than compounds (I) and (II) in the above-described photosensitive composition, as long as they are included in a typical photosensitive composition. Examples of such materials include, for example, n-type semiconductor materials, p-type semiconductor materials, and light-absorbing materials described later. They can be used alone or in combination of two or more.

[0118] (Organic film)

[0119] The organic thin film of this embodiment includes compounds (I) and (II) of this embodiment or the aforementioned material for photoelectric conversion elements. Such organic thin films can be fabricated using conventional dry or wet deposition methods. Specifically, examples include: resistance heating evaporation, electron beam evaporation, sputtering, and molecular stacking methods, which belong to vacuum processes; casting, spin coating, dip coating, blade coating, wire rod coating, and spraying methods, which belong to solution processes; inkjet printing, screen printing, offset printing, and letterpress printing methods; and soft photolithography methods such as microcontact printing. Generally, from the viewpoint of ease of processing, it is desirable for photoelectric conversion element materials to be used in processes where compounds are coated in a solution state. However, in the case of photoelectric conversion elements such as stacked organic thin films, the coating solution may erode the underlying film, therefore, dry deposition methods such as resistance heating evaporation are preferred.

[0120] For example, in a dry film deposition method, the photoelectric conversion element material of this embodiment and other materials suitable for the application of the photoelectric conversion element are mixed to form a composition, and the composition is deposited onto a substrate or other film under vacuum, thereby obtaining an organic thin film. Alternatively, in a wet film deposition method, the photoelectric conversion film of this embodiment and other materials suitable for the application of the photoelectric conversion element are mixed with a solvent to form a liquid composition, which is then coated onto a substrate or other film for printing, and subsequently dried, thereby obtaining an organic thin film.

[0121] The organic thin film of this embodiment may also contain materials other than compounds (I) and (II), which are used as materials for photoelectric conversion elements in this embodiment. The content of compounds (I) and (II) in the organic thin film of this embodiment is not particularly limited as long as they exhibit the performance required for use as materials for photoelectric conversion elements. For example, the content of compounds (I) and (II) relative to the total amount of the organic thin film may be 50% by mass or more, and from the viewpoint of more effectively and reliably exerting the effects of the present invention, it 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 of compounds (I) and (II) may be 100% by mass, respectively. When the organic thin film of this embodiment contains materials other than compounds (I) and (II), such materials are not particularly limited as long as they can be used as materials for conventional photoelectric conversion elements. Examples of such materials include, for example, n-type semiconductor materials, p-type semiconductor materials, and light-absorbing materials described later, as well as molybdenum oxide, alkali metals, and alkali metal compounds, which are referred to as doping materials. They may be used individually or in combination of two or more.

[0122] The thickness of organic thin films also depends on the resistance value / charge mobility of each material, so it cannot be limited. It is usually above 0.5nm and below 5000nm, but can be above 1nm and below 1000nm, or above 5nm and below 500nm.

[0123] From the viewpoint of more effectively and reliably exerting the effects of the present invention, the organic thin film of this embodiment preferably has a maximum absorption wavelength of the light absorption band below 450 nm.

[0124] (Photoelectric conversion element)

[0125] The photoelectric conversion element of this embodiment refers to an element that generates a charge corresponding to the amount of incident light and outputs it to the outside of the photoelectric conversion element via a capacitor (hereinafter also called a "storage section") for storing the generated charge and a transistor circuit (hereinafter also called a "readout section") for reading out. Here, the photoelectric conversion element refers to a photoelectric conversion film that absorbs at least a portion of the incident light disposed between a pair of opposing electrodes, and light is incident on the photoelectric conversion element from above the electrodes. In addition, the photoelectric conversion film is a photosensitive thin film containing a material that absorbs at least a portion of the incident light in the infrared region, and the incident light results in the generation of holes and electrons. In addition, the photoelectric conversion element of this embodiment may have a photoelectric conversion element that generates a charge corresponding to the amount of incident light in the infrared region (hereinafter also called an "infrared photoelectric conversion element"). Here, the infrared photoelectric conversion element refers to a photoelectric conversion film that absorbs infrared light (hereinafter also called an "infrared photoelectric conversion film") disposed between a pair of opposing electrodes, and light is incident on the infrared photoelectric conversion element from above the electrodes. In addition, the infrared photoelectric conversion film is a photosensitive thin film containing at least a portion of the incident light in the infrared region (hereinafter also referred to as "infrared absorbing material"), and the incident light results in the generation of holes and electrons.

[0126] Appropriate reference Figure 1 The photoelectric conversion element of this embodiment will be described below. The photoelectric conversion element 100 includes a lower electrode 102 as a first electrode film, an upper electrode 106 as 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 also have a substrate 101, which is generally insulating, on the side of the upper electrode 106 opposite to the photoelectric conversion film 110.

[0127] When the photoelectric conversion film 110 has hole transport or electron transport properties, the lower electrode 102 and the upper electrode 106 function to extract and trap holes from the photoelectric conversion film 110, or to extract and discharge electrons. The materials that can be used as these electrodes are not particularly limited as long as they have a certain degree of conductivity; however, they are preferably selected considering factors such as adhesion to adjacent photoelectric conversion films 110, electron affinity, ionization potential, and stability. Examples of materials that can be used as electrodes include 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 materials such as copper iodide and copper sulfide; conductive polymers such as polythiophene, polypyrrole, and polyaniline; and carbon. They can be used individually or in combination.

[0128] The lower electrode 102, serving as the first electrode film, is composed of a transparent conductive film, such as indium tin oxide (ITO). The material constituting the lower electrode 102 is not limited to ITO; examples include tin oxide (SnO2) based materials with added dopants and zinc oxide based materials with added dopants in zinc oxide (ZnO). Examples of zinc oxide based materials include aluminum zinc oxide (AZO) with added aluminum (Al), gallium zinc oxide (GZO) with added gallium (Ga), and indium zinc oxide (IZO) with added indium (In). Alternatively, examples of materials constituting the lower electrode 102 include CuI, InSbO4, ZnMgO, CuInO2, MgIN2O4, CdO, and ZnSnO3. The thickness of the lower electrode 102 is, for example, 5 nm or more and 3000 nm or less, or 10 nm or more and 300 nm or less.

[0129] The upper electrode 106, serving as the second electrode film, can be made of the same light-transmitting conductive film as the lower electrode 102, or it can be made of a metal commonly used in photoelectric conversion elements, such as aluminum. Furthermore, in a solid-state imaging device where the solid-state imaging element is used as a pixel, the upper electrode 106 can be separated from each pixel, or it can be formed as an electrode shared by all pixels. The thickness of the upper electrode 106 can be, for example, 5 nm or more and 3000 nm or less, or 5 nm or more and 500 nm or less, or 10 nm or more and 300 nm or less.

[0130] The conductivity of the materials used in electrodes such as the first and second electrode films is not particularly limited as long as it does not impede the light reception of the photoelectric conversion element. From the viewpoint of signal strength and power consumption of the photoelectric conversion element, it is preferable to have the highest possible conductivity. For example, as a transparent electrode, an ITO film with a conductivity of 300 Ω / □ or less can function fully as an electrode. However, commercially available substrates with ITO films having a conductivity of around a few Ω / □ (e.g., 5 to 9 Ω / □) are also available, and such high conductivity substrates are desirable.

[0131] The thickness of the electrode when using an ITO film can be arbitrarily selected considering conductivity, typically between 5 nm and 3000 nm, preferably between 10 nm and 300 nm. Commonly known methods for forming ITO films include vapor deposition, electron beam deposition, sputtering, chemical reaction, and coating. Depending on the requirements, the ITO film disposed on the substrate can be subjected to UV-ozone treatment or plasma treatment.

[0132] Furthermore, when multiple photoelectric conversion films with different detection wavelengths are stacked, the electrode film used between each photoelectric conversion film needs to allow light of wavelengths other than those detected by each photoelectric conversion film to pass through. From this point of view, the electrode film is preferably made of a material that allows more than 90% of the incident light to pass through, and more preferably a material that allows more than 95% of the light to pass through. It should be noted that the electrode film described above refers to the film of the electrode other than the aforementioned pair of electrodes.

[0133] Furthermore, in this embodiment, if a visible photoelectric conversion unit for sensing infrared light or light from different visible light regions is further provided at the lower part of the photoelectric conversion element, the transmittance of visible light and infrared light of the electrodes used in the photoelectric conversion element is preferably 90% or more, and more preferably 95% or more.

[0134] As the electrode material that meets these conditions, a transparent conductive oxide (TCO) with high transmittance to visible and infrared light and low resistivity is preferred. Metal thin films such as gold can also be used as electrodes, but if a transmittance of 90% or higher is required, the resistivity increases drastically. Therefore, TCO is preferred as the electrode. ITO, IZO, AZO, FTO, SnO2, TiO2, and ZnO2 are particularly preferred as TCOs.

[0135] There are no particular limitations on the method for forming the electrode; it can be appropriately selected considering its compatibility with the electrode material. When using a transparent electrode, specific methods for its formation include wet methods such as printing and coating, physical methods such as vacuum evaporation, 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, methods for its formation include electron beam deposition, sputtering, resistance heating evaporation, chemical reaction methods (e.g., sol-gel method), and methods involving coating a dispersion of the metal oxide. Moreover, UV-ozone treatment and plasma treatment can also be applied to films of transparent conductive metal oxides such as ITO.

[0136] Furthermore, from the viewpoint of more effectively and reliably exerting the effects of the present invention, the photoelectric conversion element of this embodiment preferably includes 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 includes a photoelectric conversion layer and two auxiliary layers located between the photoelectric conversion layer and the second electrode film. Among the two auxiliary layers, the auxiliary layer closer to the second electrode film contains compound (I) or (II) of this embodiment.

[0137] The main reason why such a photoelectric conversion element can suppress leakage current in the dark is not yet certain, but the inventors have considered the following. The photoelectric conversion element of this embodiment has two auxiliary layers between the photoelectric conversion layer and the second electrode film, wherein the auxiliary layer near the second electrode film contains compound (I) or (II). Therefore, it is believed that the lower HOMO energy level possessed by compound (I) or (II) can achieve a rectification effect that suppresses the migration of electrons generated in the photoelectric conversion layer to the second electrode film, thereby suppressing leakage current in the dark (hereinafter also referred to as "dark current"). However, the main reason is not limited to this. Furthermore, the photoelectric conversion element of this embodiment can also have high photoelectric conversion efficiency. This is believed to be because by containing compound (I) or (II) in the auxiliary layer near the second electrode film, the chemical affinity between the second electrode film and the photoelectric conversion film can be improved, and the energy gradient for smoother electron migration to the second electrode film can be utilized. However, the main reason is not limited to this.

[0138] As one embodiment of this invention, the photoelectric conversion film 110 may contain the material for the photoelectric conversion element of this embodiment, or it may contain the aforementioned organic thin film. More specifically, for example, the photoelectric conversion film 110 includes a photoelectric conversion layer 104, a first auxiliary layer 103 located on the side of the lower electrode film 102 of the photoelectric conversion layer 104, and a second auxiliary layer 105 located on the side of the upper electrode film 106 of the photoelectric conversion layer 104. It should be noted that, although Figure 1The photoelectric conversion film 110 shown includes a first auxiliary layer 103 and a second auxiliary layer 105, but the photoelectric conversion film may include only one of these auxiliary layers. Alternatively, the photoelectric conversion film may not have any auxiliary layers and may only have a photoelectric conversion layer 104. When the photoelectric conversion film does not have auxiliary layers, the photoelectric conversion layer 104 is the aforementioned organic thin film; when the photoelectric conversion film has auxiliary layers, at least one of the photoelectric conversion layer 104 and the auxiliary layer is the aforementioned organic thin film. However, from the viewpoint of more effectively and reliably exerting the effects of the present invention, the auxiliary layer is preferably the aforementioned organic thin film containing the material for the photoelectric conversion element of this embodiment.

[0139] As one embodiment of this invention, 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. Of these 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. It should be noted that although... Figure 2 The photoelectric conversion film 110 shown has a first auxiliary layer 103, a second auxiliary layer 105 and a third auxiliary layer 107, but the photoelectric conversion film may also not have an auxiliary layer between the lower electrode 102 and the photoelectric conversion layer 104.

[0140] The photoelectric conversion layer 104 can be an organic semiconductor film commonly used as a photoelectric conversion layer, or it can be the aforementioned organic thin film. Furthermore, in the photoelectric conversion layer 104, these organic semiconductor films and organic thin films can be one or more layers. In the case of a single layer, a p-type organic semiconductor film, an n-type organic semiconductor film, or a mixture thereof (hereinafter, also referred to as a "bulk heterostructure") is used. On the other hand, in the case of multiple layers, the number of layers can be approximately 2 to 10, and it can be a structure in which any of the p-type organic semiconductor film, n-type organic semiconductor film, or a mixture thereof (hereinafter, also referred to as a "bulk heterostructure") is stacked, with buffer layers inserted between the layers.

[0141] The photoelectric conversion layer 104 in this embodiment may contain the material used in the photoelectric conversion element of this embodiment, or it may not contain the material used in the photoelectric conversion element of this embodiment, or it may contain materials other than the material used in the photoelectric conversion element of this embodiment. When the photoelectric conversion layer 104 contains at least one of organic p-type semiconductors, organic n-type semiconductors, and light-absorbing materials, it can more efficiently convert incident light energy of the desired wavelength into an electrical signal, and is therefore preferred. Among the light-absorbing materials, if it is an organic p-type semiconductor, it is preferred to be one that readily donates electrons and has a low ionization potential; or if it is an organic n-type semiconductor, it is preferred to be one that readily accepts electrons and has a high electron affinity. Since it can more efficiently convert incident light energy into an electrical signal, it is therefore preferred. Here, the ionization potential (HOMO level) refers to the value measured by photoelectron yield spectroscopy or photoelectron spectroscopy. In addition, electron affinity (LUMO level) refers to the value obtained by subtracting the HOMO level from the energy band gap calculated from the longest wavelength absorption end of the near-infrared spectrum, or it refers to the value measured by inverse photoelectron spectroscopy.

[0142] When using an organic semiconductor film, the film can be a single layer or two or more layers. The organic semiconductor film can be an organic p-type semiconductor film, an organic n-type semiconductor film, a light-absorbing material film, or a mixture of these (bulk heterostructure). In particular, the organic semiconductor film preferably has a bulk heterojunction structure layer. In this case, by incorporating a bulk heterojunction structure into the photoelectric conversion film, the short carrier diffusion length of the photoelectric conversion film can be compensated for, thereby improving the photoelectric conversion efficiency.

[0143] The thickness of the photoelectric conversion layer 104 can 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.

[0144] The following section provides a detailed description of organic semiconductors.

[0145] Organic p-type semiconductors are donor organic semiconductors (hereinafter also referred to as "donor organic compounds"), which are organic compounds, mainly represented by hole-transporting organic compounds, that have the property of readily donating electrons. More specifically, they are organic compounds with a low ionization potential when two organic materials are used in contact. Therefore, as a donor organic compound, any organic compound can be used as long as it has electron-donating properties.

[0146] 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, anthocyanin compounds, oxonol compounds, polyamine compounds, indole compounds, pyrrole compounds, pyrazole compounds, polyaryl compounds, fused aromatic carbocyclic compounds (e.g., naphthalene derivatives, anthracene derivatives, phenanthrene derivatives, tetraphenylene derivatives, pyrene derivatives, perylene derivatives, fluoranthene derivatives), and metal complexes with nitrogen-containing heterocyclic compounds as ligands. It should be noted that, as mentioned above, any organic compound with an ionization potential lower than that of an organic compound used as an acceptor organic compound can be used as a donor organic semiconductor.

[0147] Organic n-type semiconductors are acceptor organic semiconductors (hereinafter also referred to as "acceptor organic compounds"), which refer to organic compounds, mainly represented by electron-transporting organic compounds, that have the property of readily accepting electrons. More specifically, they refer to organic compounds that have a high electron affinity when two organic compounds are brought into contact. Therefore, as an acceptor organic compound, any organic compound that has electron-accepting properties can be used.

[0148] Examples of such acceptor organic compounds include fused aromatic carbocyclic compounds (e.g., naphthalene derivatives, anthracene derivatives, phenanthrene derivatives, tetraphenylbenzene derivatives, pyrene derivatives, perylene derivatives, fluoranthene derivatives, fullerene derivatives), and five- to seven-membered heterocyclic compounds containing nitrogen, oxygen, and sulfur atoms (e.g., pyridine, pyrazine, pyrimidine, pyridazine, triazine, quinoline, quinoxaline, quinazoline, phthalazine, borazine, isoquinoline, pteridine, acridine, phenazine, phenanthrene). The following compounds are considered as ligands: tetrazolium, pyrazole, imidazole, thiazole, oxazole, indazole, benzimidazole, benzotriazole, benzoxazole, benzothiazole, carbazole, purine, triazolidine, triazolidine, tetrazalindene, oxadiazole, imidazole pyridine, pyrrolidine, pyrrolopyridine, thiadiazopyridine, dibenzo-acoxane, and tribenzo-acoxane), polyarylene compounds, fluorene compounds, cyclopentadiene compounds, silyl compounds, and metal complexes having nitrogen-containing heterocyclic compounds as ligands. Furthermore, not limited to these, as mentioned above, any organic compound with an electron affinity greater than that of an organic compound used as a donor organic compound can be used as an acceptor organic semiconductor.

[0149] Optically absorbing materials are compounds that possess a maximum absorption wavelength in the visible light region, particularly between 450 nm and 650 nm. It is desirable that the absorption intensity of the optically absorbing material at its maximum absorption wavelength is greater than that of either the donor or acceptor organic compound at the same wavelength. By possessing such an absorption intensity, the optically absorbing material can selectively absorb incident light at its maximum absorption wavelength. After the incident light is absorbed by the optically absorbing material and the photons become excitons, exciton separation occurs at the interface between the donor and acceptor organic compounds, thereby efficiently generating charge carriers such as holes and electrons.

[0150] As such light-absorbing materials, compounds commonly referred to as pigments can be used. Examples include phthalocyanine derivatives, phthalocyanine derivatives, quinacridone derivatives, porphyrin derivatives, naphthalene or perylene derivatives, perylene phthalocyanine derivatives, styryl derivatives, anthocyanin derivatives, hemicyanine derivatives, quinocyanine derivatives, rhodacyanine derivatives, oxacyanine derivatives, hemicyanine derivatives, ketone acid derivatives, squaric acid cyanine derivatives, azamethine derivatives, aryl derivatives, azo derivatives, azomethyl base derivatives, metallocene derivatives, fenazine anhydride derivatives, phenothiazine derivatives, polyene derivatives, acridine derivatives, acridine ketone derivatives, diphenylamine derivatives, triphenylamine, naphthylamine, and styrylamine triarylamine derivatives, quinacridone derivatives, phenoxazine derivatives, chlorophyll derivatives, rhodamine derivatives, diphenylmethane or triphenylmethane derivatives, xanthones, acridine derivatives, phenoxazine derivatives, quinoline derivatives, and oxazine derivatives. Thiazide derivatives, quinone derivatives, benzoquinone derivatives, naphthoquinone derivatives, anthraquinone derivatives, indigo or thioindigo derivatives, pyrrole derivatives, pyridine derivatives, dipyrrole methylene derivatives, indole derivatives, diketopyrrole-pyrrole derivatives, coumarin derivatives, fluorene derivatives, fluorenone derivatives, fluoranthene derivatives, anthracene derivatives, pyrene derivatives, carbazole derivatives, phenylenediamine derivatives, benzidine derivatives, phenanthrene derivatives, imidazole derivatives, oxazoline derivatives, thiazoline derivatives, triazole derivatives, thiadiazole derivatives, oxazole derivatives, thiazolium derivatives, thiazolium derivatives, thiadiazole derivatives, thiophene derivatives, selenophene derivatives, thiorrole derivatives, germane heterocyclopentadiene derivatives, piracene derivatives, phenyleneethylene derivatives, pentabenzene derivatives, rubrene derivatives, thiophene-thiophene derivatives, benzodithiophene derivatives, xanthonesone-xanthonesone derivatives, and fullerene derivatives. It should be noted that this is not the only limitation. As mentioned above, any compound whose absorption intensity is greater than that of the donor or acceptor organic compound at its maximum absorption wavelength can be used as a light-absorbing material. Furthermore, light-absorbing materials can also function as either donor or acceptor organic compounds.

[0151] As one embodiment, the first auxiliary layer 103 can be a single layer or two or more layers. The first auxiliary layer 103 may include at least one of a hole blocking layer and an electron transport layer. When the first auxiliary layer 103 includes both, the electron transport layer and the hole blocking layer are typically stacked sequentially from the photoelectric conversion layer 104 side. The electron transport layer functions to transport electrons generated in the photoelectric conversion layer 104 to the first electrode 102 and to block holes from migrating from the first electrode 102, the electron transport destination, to the photoelectric conversion layer 104. The hole blocking layer functions to prevent holes from migrating from the first electrode 102 to the photoelectric conversion layer 104, prevent recombination within the photoelectric conversion layer 104, reduce dark current, reduce noise, and expand the dynamic range. Alternatively, a single layer may have the functions of 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.

[0152] As one embodiment, the second auxiliary layer 105 can be a single layer or two or more layers. The second auxiliary layer 105 may include at least one of an electron blocking layer and a hole transport layer. When the second auxiliary layer 105 includes both, the hole transport layer and the electron blocking layer are typically stacked sequentially from the photoelectric conversion layer 104 side. The hole transport layer functions to transport generated holes from the photoelectric conversion layer 104 to the second electrode 106 and to block electrons from migrating from the second electrode 106, the destination of hole transport, to the photoelectric conversion layer 104. The electron blocking layer functions to prevent electrons from migrating from the second electrode 106 to the photoelectric conversion layer 104, prevent recombination within the photoelectric conversion layer 104, reduce dark current, reduce noise, and expand the dynamic range. Alternatively, a single layer may have both the functions of 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.

[0153] In one embodiment, the third auxiliary layer 107 is an auxiliary layer closer to the upper electrode 106 than the second auxiliary layer 105, and can be, for example, a hole blocking layer. The hole blocking layer functions to prevent holes from migrating from the second electrode 106 to the photoelectric conversion layer 104, prevent recombination within the photoelectric conversion layer 104, reduce dark current, reduce noise, and expand the dynamic range. It should be noted that at least one layer located between the photoelectric conversion layer 104 and the upper electrode 106 can have the functions of 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 third auxiliary layer 107 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.

[0154] The material for the photoelectric conversion element in this embodiment may be included in any of the first auxiliary layer 103, the second auxiliary layer 105, and the third auxiliary layer 107, but is preferably included in the first auxiliary layer 103 and / or the third auxiliary layer 107. In the photoelectric conversion element of this embodiment, it is preferable that the first auxiliary layer 103 and / or the third auxiliary layer 107 comprises the aforementioned organic thin film. Furthermore, it is more preferable that the material for the photoelectric conversion element of this embodiment is included in at least one of the hole blocking layer and the electron transport layer in the first auxiliary layer 103 and / or 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 aforementioned organic thin film. Therefore, the effects of the present invention can be performed more effectively and reliably.

[0155] As one embodiment of this invention, compound (I) or (II) is included in at least a third auxiliary layer 107 among these auxiliary layers. The third auxiliary layer 107 may contain materials other than compound (I) or (II). The content of compound (I) or (II) in the third auxiliary layer 107 is not particularly limited, as long as they each exhibit the performance required for use as an auxiliary layer near the upper electrode 106. For example, its content relative to the total amount of the third auxiliary layer 107 may be 50% by mass or more, but from the viewpoint of more effectively and reliably exerting the effect of the present invention in suppressing leakage current in the dark, it 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 its content may be 100% by mass.

[0156] Hereinafter, we will describe the compounds (I) or (II) of this embodiment that may be included in each of the auxiliary layers, as well as materials other than those for photoelectric conversion elements.

[0157] There are no particular limitations on the materials used as hole transport layers, as long as they are known to be used as hole transport layers in photoelectric conversion elements such as solid-state imaging devices. Examples include polyaniline and its doped materials, and cyanide compounds described in International Publication No. 2006 / 019270.

[0158] More specifically, materials constituting the hole transport layer include iodides such as selenium and cuprous iodide (CuI), cobalt complexes such as layered cobalt oxides, CuSCN, molybdenum oxide (MoO3, etc.), nickel oxide (NiO, etc.), 4CuBr·3S (C4H9), and organic hole transport materials. Among these, cuprous iodide (CuI) is an example of an iodide. AxCoO2 is an example of a layered cobalt oxide (where A represents Li, Na, K, Ca, Sr, or Ba, and 0 ≤ X ≤ 1). In addition, examples of organic hole transport materials include polythiophene derivatives such as poly-3-hexylthiophene (P3HT), poly(3,4-ethylenedioxythiophene), and polythiophene derivatives such as PEDOT (e.g., the trade name "Baytron P" manufactured by Starck-V TECH), fluorene derivatives such as 2,2',7,7'-tetra-(N,N-di-p-methoxyaniline)-9,9'-spirodifluorene (spiro-MeO-TAD), carbazole derivatives such as polyvinylcarbazole, triphenylamine derivatives, diphenylamine derivatives, polysilane derivatives, and polyaniline derivatives. Furthermore, examples of materials for hole transport layers include compound semiconductors with monovalent copper such as CuInSe2 and copper sulfide (CuS), gallium phosphide (GaP), nickel oxide (NiO), cobalt oxide (CoO), ferrous oxide (FeO), bismuth oxide (Bi2O3), molybdenum oxide (MoO2), and chromium oxide (Cr2O3).

[0159] Furthermore, when the hole transport layer has a LUMO energy level higher than that of the photoelectric conversion film, it can impart an electron blocking function that has a rectifying effect, suppressing the migration of electrons generated in the photoelectric conversion film to the electrode side, and is therefore preferred. Such a hole transport layer is also called an electron blocking layer.

[0160] Examples of low-molecular-weight organic compounds that form electron-blocking layers include aromatic diamines 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); oxazoles, oxadiazoles, triazoles, imidazoles, imidazole ketones, piracetam derivatives, pyrazoline derivatives, tetrahydroimidazolium, polyarylalkanes, butadiene, 4,4',4” tris(N-(3-methylphenyl)N-phenylamino)triphenylamine (m-MTDATA), porphyrins, tetraphenylporphyrin copper, phthalocyanines, copper phthalocyanine and titanium phthalocyanine, triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkanes, pyrazoline derivatives, pyrazoline ketone derivatives, phenylenediamine derivatives, arylamine derivatives, and ammonia. Substituted chalcone derivatives, oxazole derivatives, styryl anthracene derivatives, fluorenone derivatives, hydrazone derivatives, and silazane derivatives are examples. Additionally, high-molecular-weight organic compounds include polymers and derivatives of phenylenevinylene, fluorene, carbazole, indole, pyrene, pyrrole, methylpyridine, thiophene, acetylene, and diacetylene. Even if not electron-donating compounds, compounds with sufficient hole-transporting properties can be used as materials constituting the electron blocking layer. Furthermore, inorganic compounds constituting the electron blocking layer include, for example, metal oxides such as calcium oxide, chromium oxide, copper chromium oxide, manganese oxide, cobalt oxide, nickel oxide, copper oxide, copper gallium oxide, copper strontium oxide, niobium oxide, molybdenum oxide, copper indium oxide, silver indium oxide, and iridium oxide, as well as selenium, tellurium, and antimony sulfide. These can be used alone or in combination of two or more.

[0161] 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.

[0162] The method for forming the hole transport layer and the electron blocking layer can be any of the methods known in the art, including dry film deposition methods such as vacuum evaporation and wet film deposition methods such as solution coating. From the viewpoint of enabling leveling of the coating surface, wet film deposition methods are preferred. Examples of dry film deposition methods include evaporation methods such as vacuum evaporation and sputtering. Evaporation can be any of physical vapor deposition (PVD) and chemical vapor deposition (CVD), with physical vapor deposition such as vacuum evaporation being preferred. Examples of wet film deposition methods include inkjet printing, spraying, nozzle printing, spin coating, dip coating, casting, die coating, roll coating, bar coating, and gravure coating.

[0163] As for the materials constituting the electron transport layer, there are no particular limitations as long as they are known to be used as electron transport layers in photoelectric conversion elements such as solid-state imaging elements. Examples include: perfluorinated octaazaporphyrins and p-type semiconductors (such as perfluoropentabenzene, perfluorophthalocyanine, etc.), fullerenes, fullerene derivatives (such as [6,6]-Phenyl-C61-Butyric Acid Methyl Ester, PCBM, etc.), organic compounds such as perylene, indene and indene 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 (Y2O3, etc.), and strontium titanate (SrTiO3, etc.). The electron transport layer can be porous or dense. When stacking them, it is preferable to stack and provide a porous electron transport layer and a dense electron transport layer sequentially from the photoelectric conversion film side.

[0164] Furthermore, when the electron transport layer has a HOMO energy level lower than that of the photoelectric conversion film, it can impart a hole-blocking function that has a rectifying effect, suppressing the migration of holes generated in the photoelectric conversion film to the counter electrode side, and is therefore preferred. Such an electron transport layer is also called a hole-blocking layer.

[0165] Materials constituting hole-blocking layers include, for example, oxadiazole derivatives such as 1,3-bis(4-tert-butylphenyl-1,3,4-oxadiazolyl)benzene (OXD-7), anthraquinone dimethyl derivatives, diphenylquinone derivatives, copper hydroxide, phenanthrene and their derivatives, triazine compounds, triazole compounds, tri(8-hydroxyquinoline)aluminum complexes, bis(4-methyl-8-quinoline)aluminum complexes, thiophene compounds, porphyrin compounds, styrene compounds such as DCM (4-dicyanomethylene-2-methyl-6-(4-(dimethylaminostyryl))-4Hpyran), n-type semiconductor materials such as naphthalene tetracarboxylic anhydride (NTCDA), naphthalene tetracarboxylic diimide, perylene tetracarboxylic anhydride (PTCDA), 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 because they improve the electrical connection with the counter electrode. They can be used alone or in combination of two or more.

[0166] 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.

[0167] The method for forming the electron transport layer and hole blocking layer can be any of the methods known in the past, or any of the dry film formation methods such as vacuum evaporation and wet film formation methods such as solution coating. From the viewpoint of being able to level the coating surface, wet film formation is preferred. Examples of dry film formation methods include evaporation methods such as vacuum evaporation and sputtering. Evaporation can be any of physical vapor deposition (PVD) and chemical vapor deposition (CVD), with physical vapor deposition such as vacuum evaporation being preferred. Examples of wet film formation methods include inkjet printing, spraying, nozzle printing, spin coating, dip coating, casting, mold coating, roll coating, bar coating, and gravure coating.

[0168] The photoelectric conversion element of this embodiment may have an auxiliary layer different from the first auxiliary layer 103, either as a single layer or as two or more layers, between the first auxiliary layer 103 and the lower electrode 102. Examples of such an auxiliary layer include a hole injection layer for improving hole injection from the lower electrode 102 to the first auxiliary layer 103. Examples of materials constituting the hole injection layer include phthalocyanine derivatives, star-burst amines such as m-MTDATA (4,4',4”-tris[phenyl(m-tolyl)amino]triphenylamine), polythiophene materials such as PEDOT (poly(3,4-ethylenedioxythiophene)), and polymeric materials such as polyvinylcarbazole derivatives. The thickness of this auxiliary layer may also be the same as that of the first auxiliary layer 103.

[0169] The photoelectric conversion element of this embodiment may have an auxiliary layer different from the second auxiliary layer 105, either as a single layer or as two or more layers, between the second auxiliary layer 105 and the upper electrode 106. Examples of such auxiliary layers include an electron injection layer and an electron transport layer for improving electron injection from the upper electrode 106 to the second auxiliary layer 105. Examples of materials constituting the electron injection layer include metals such as cesium, lithium, and strontium, as well as lithium fluoride. The materials constituting the electron transport layer may be the same as described above. Furthermore, the thickness of this auxiliary layer may be the same as that of the second auxiliary layer 105.

[0170] The photoelectric conversion element of this embodiment may have an auxiliary layer, different from the second auxiliary layer 105 and the third auxiliary layer 107, between the third auxiliary layer 107 and the upper electrode 106, in one or two or more layers. Examples of such auxiliary layers include an electron injection layer and an electron transport layer for improving electron injection from the upper electrode 106 to the third auxiliary layer 107. Examples of materials constituting the electron injection layer include metals such as cesium, lithium, and strontium, as well as lithium fluoride. The materials constituting the electron transport layer may be the same as described above. Furthermore, the thickness of this auxiliary layer may be the same as that of the second auxiliary layer 105.

[0171] In addition to the layers described above, the photoelectric conversion element of this embodiment may also include at least one of an interlayer contact improvement layer and an anti-crystallization layer located between these layers.

[0172] The interlayer contact improvement layer serves to mitigate damage to the film closest to the lower layer, such as the photoelectric conversion film 110, during the deposition of the upper electrode 106. In particular, high-energy particles present in the apparatus used for deposition of the upper electrode 106, such as sputtering particles, secondary electrons, Ar particles, and oxygen anions, can collide with the film closest to the lower layer and cause deterioration, sometimes resulting in increased leakage current, decreased sensitivity, and other performance degradation. As one method to prevent this, it is preferable to provide an interlayer contact improvement layer on the upper layer of the film closest to the lower layer. The materials for the interlayer contact improvement layer are preferably organic compounds such as copper phthalocyanine, NTCDA, PTCDA, [dipyrazine[2,3-F:2',3'-H]quinoxaline-2,3,6,7,10,11-hexacarboxynitrile] (HATCN), acetylacetone complexes, BCP, organometallic compounds, and inorganic compounds such as MgAg and MgO. The thickness of the interlayer contact improvement layer varies depending on the composition of the photoelectric conversion film, the thickness of the electrode film, etc. In particular, from the viewpoint of selecting materials that do not absorb in the visible region or using them with a thin thickness, it is preferred to be 2nm or more and 500nm or more.

[0173] As described above, in the photoelectric conversion element of this embodiment, a capacitor (i.e., a storage section) for storing the generated charge and a transistor circuit (i.e., a readout section) for reading are connected via a connection portion made of conductive material. Additionally, as needed, the photoelectric conversion element may include a protective structure such as a protective film to prevent damage from external air, a substrate for maintaining strength, and a microlens for focusing light.

[0174] The readout section is provided to read the signal corresponding to the charge generated in the photoelectric conversion film. The readout section is, for example, composed of a CCD, CMOS circuit, or TFT circuit, and is preferably shielded from light by a light-shielding layer disposed within an insulating layer. The readout circuit is electrically connected to its corresponding electrode via a connector. It should be noted that, to ensure the required amount of charge is read out, an accumulation section, such as a capacitor, may be sandwiched between the electrode and the connector. The connector, embedded in the insulating layer, is a plug or similar device used to electrically connect the electrode (e.g., a transparent electrode or a counter electrode) to the readout section. In the case of a solid-state imaging element with such a configuration, when light is incident, it strikes the photoelectric conversion film, where a charge is generated. Electrons in the generated charge are captured (and accumulated) by one electrode, and holes are captured by the other electrode. A voltage signal corresponding to this amount is output from the readout section to the outside of the solid-state imaging element.

[0175] (Camera element)

[0176] As one embodiment of this invention, the imaging element of this invention can be configured the same as conventional imaging elements as long as it includes the photoelectric conversion element of this invention. For example, the imaging element of this invention is provided by arranging a plurality of photoelectric conversion elements of this invention in an array. That is, by arranging a plurality of photoelectric conversion elements in an array, a solid-state imaging element is constructed that displays incident position information in addition to the incident light amount.

[0177] The imaging element of this embodiment can include one photoelectric conversion element of this embodiment, or it can be formed by stacking two or more. When two or more photoelectric conversion elements of this embodiment are stacked, each photoelectric conversion element can selectively detect light of different wavelengths 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. Thus, the imaging element can acquire multiple color signals in a single pixel without using a color filter. In addition, color signals other than those detected by the photoelectric conversion elements of this embodiment can also be sensed by a device having a conventionally known silicon photodiode.

[0178] In imaging elements, a device having multiple photoelectric conversion elements and silicon photodiodes can be stacked, provided that the photoelectric conversion element positioned closer to the light source does not obstruct (i.e., transmits) the absorption wavelength of other photoelectric conversion elements positioned behind it when viewed from the light source side.

[0179] In imaging elements, from the viewpoint of ease of forming, photoelectric conversion elements can be partially configured as thin films on the same plane where adjacent photoelectric conversion elements do not have structural separation from each other.

[0180] The imaging element in this embodiment may also include a substrate. The substrate is used to laminate layers thereon to manufacture the imaging element, or to improve the mechanical strength of the imaging element. There are no particular limitations on the type of substrate; examples include semiconductor substrates, glass substrates, and plastic substrates.

[0181] (Optical sensor)

[0182] The light sensor in this embodiment only needs to include the imaging element of this embodiment; otherwise, its configuration can be the same as that of conventional light sensors. This light sensor can receive light in the imaging element of this embodiment and output an electrical signal corresponding to the amount of light received.

[0183] (Solid-state camera device)

[0184] The solid-state camera device of this embodiment only needs to include the imaging element of this embodiment; other than that, the configuration can be the same as that of conventional solid-state camera devices. The solid-state camera device of this embodiment can be, for example, a CMOS image sensor, or it can have pixel portions on a semiconductor substrate that serve as imaging areas, and further, peripheral circuit portions having row scanning portions, horizontal selection portions, column scanning portions, and system control portions are provided in the surrounding area or vertically below the pixel portions. The aforementioned pixel portions have the imaging element of this embodiment.

[0185] The photoelectric conversion element of this embodiment has the following advantages by using the material for the photoelectric conversion element of this embodiment. Specifically, the photoelectric conversion element of this embodiment is less prone to short circuits or pinholes, thus reducing the dark current value. As a result, the photoelectric conversion element of this embodiment exhibits excellent leakage current prevention (especially in the dark). Furthermore, the photoelectric conversion element of this embodiment tends to easily display a high brightness-to-dark ratio, in which case it has even better leakage current prevention. Additionally, although the material for the photoelectric conversion element of this embodiment is difficult to aggregate, the transport properties of holes and electrons are excellent, thus increasing the photoelectric conversion efficiency. Furthermore, by using the material for the photoelectric conversion element of this embodiment, the photoelectric conversion element of this embodiment also exhibits good heat resistance, improving durability in manufacturing processes and practical environments.

[0186] Example

[0187] The present invention will be described in more detail below through examples, but the present invention is not limited to these examples. It should be noted that the synthesized compounds may be further purified by sublimation as needed.

[0188] <Synthesis example 1>

[0189]

[0190] 6.0 g of 1,4,5,8-naphthalenetetracarboxylic dianhydride (1) (hereinafter referred to as "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 9.6 g of 4-methylsulfonylaniline (manufactured by Tokyo Chemical Industry Co., Ltd.) (2.5 molar equivalents relative to compound (1)) were added to 90 mL of m-cresol (manufactured by Tokyo Chemical Industry Co., Ltd.) to obtain a mixture. The mixture was stirred at 180 °C for 12 hours. Then, it was cooled to room temperature, methanol was added, and the precipitate was filtered. Then, after washing with methanol, the precipitate was purified by sublimation to obtain compound (2) as a white solid. The results of its NMR measurements are shown below.

[0191] 1HNMR (500MHz, TFA-d): 9.01 (s, 4H), 8.29 (d, 4H), 7.74 (d, 4H), 3.35 (s, 6H)

[0192] <Synthesis example 2>

[0193]

[0194] Compound (3) was obtained in the same manner as in Synthesis Example 1, except that 4-phenylsulfonylaniline (manufactured by Ambeed Inc.) in a 2.5 molar equivalent relative to compound (1) was used instead of 4-methylsulfonylaniline. The results of its NMR measurements are shown below.

[0195] 1 HNMR (500MHz, DMSO-d6): 8.70 (s, 4H), 8.19 (d, 4H), 8.08 (d, 4H), 7.78~7.69 (m, 10H)

[0196] <Synthesis example 3>

[0197]

[0198] Compound (4) was obtained in the same manner as in Synthesis Example 1, except that 4-trifluoromethylsulfonylaniline (manufactured by Apollo Scientific Ltd.) was used in place of 2.5 molar equivalents relative to compound (1). The results of its NMR measurements are shown below.

[0199] 1 HNMR (500MHz, DMSO-d6): 8.77 (s, 4H), 8.42 (d, 4H), 8.04 (d, 4H)

[0200] <Synthesis example 4>

[0201]

[0202] Compound (7) was obtained in the same manner as in Synthesis Example 1, except that 2-fluoro-4-methylsulfonylaniline (manufactured by Apollo Scientific Ltd.) in 2.5 molar equivalents relative to compound (1) was used instead of 4-methylsulfonylaniline. The results of its NMR measurements are shown below.

[0203] 1 HNMR (500MHz, TFA-d): 8.98 (s, 4H), 8.03 (dd, 2H), 7.99 (dd, 2H), 7.66 (dd, 2H), 3.32 (s, 6H)

[0204] <Synthesis example 5>

[0205]

[0206] Compound (8) was obtained in the same manner as in Synthesis Example 1, except that 3-fluoro-4-methylsulfonylaniline (manufactured by Apollo Scientific Ltd.) in a 2.5 molar equivalent relative to compound (1) was used instead of 4-methylsulfonylaniline. The results of its NMR measurements are shown below.

[0207] 1 HNMR (500MHz, TFA-d): 8.98 (s, 4H), 8.24 (dd, 2H), 7.50 (dd, 2H), 7.47 (dd, 2H), 3.46 (s, 6H)

[0208] <Synthesis example 6>

[0209]

[0210] Compound (9) was obtained in the same manner as in Synthesis Example 1, except that 3-methylsulfonylaniline (manufactured by Combi-Blocks Inc.) in a 2.5 molar equivalent relative to compound (1) was used instead of 4-methylsulfonylaniline. The results of its NMR measurements are shown below.

[0211] 1 HNMR (500MHz, TFA-d): 8.98 (s, 4H), 8.22~8.15 (m, 4H), 7.90~7.79 (m, 4H), 3.32 (s, 6H)

[0212] <Synthesis Example 7>

[0213]

[0214] Compound (10) was obtained in the same manner as in Synthesis Example 1, except that 3-trifluoromethylsulfonylaniline (manufactured by Apollo Scientific Ltd.) in 2.5 molar equivalents relative to compound (1) was used instead of 4-methylsulfonylaniline. The results of its NMR measurements are shown below.

[0215] 1 HNMR (500MHz, DMSO-d6): 8.76 (s, 4H), 8.44 (d, 2H), 8.31 (d, 2H), 8.19 (d, 2H), 8.09 (t, 2H)

[0216] <Synthesis example 8>

[0217]

[0218] Compound (11) was obtained in the same manner as in Synthesis Example 1, except that 2-fluoro-5-methylsulfonylaniline (manufactured by Combi-Blocks Inc.) in a 2.5 molar equivalent relative to compound (1). The results of its NMR measurements are shown below.

[0219] 1 HNMR (500MHz, TFA-d): 9.03 (s, 4H), 8.30~8.27 (m, 4H), 7.64 (t, 2H), 3.36 (s, 6H)

[0220] <Synthesis Example 9>

[0221]

[0222] Compound (12) was obtained in the same manner as in Synthesis Example 1, except that 4-fluoro-3-methylsulfonylaniline (manufactured by Apollo Scientific Ltd.) was used in place of 2.5 molar equivalents relative to compound (1). The results of its NMR measurements are shown below.

[0223] 1 HNMR (500MHz, TFA-d): 8.98 (s, 4H), 8.16 (dd, 2H), 7.82~7.79 (m, 2H), 7.55 (t, 2H), 3.47 (s, 6H)

[0224] <Synthesis example 10>

[0225]

[0226] 2.0 g of compound (1) (manufactured by Tokyo Chemical Industry) and 1.5 g of aniline (manufactured by Tokyo Chemical Industry) (2.2 molar equivalents relative to compound (1)) were added to 15 mL of acetic acid (manufactured by Tokyo Chemical Industry) to obtain a mixture. The mixture was stirred under reflux at 125 °C for 8 hours. Then, it was cooled to room temperature, methanol was added, and the precipitated mixture was filtered. After washing with methanol, pyridine was added and stirred for 5 minutes. Then, it was filtered, washed with methanol, and purified by sublimation to obtain compound (5) as a white solid. The results of its NMR measurements are shown below.

[0227] 1 HNMR (500MHz, DMSO-d6): 8.73 (s, 4H), 7.58~7.45 (m, 10H)

[0228] <Synthesis Example 11>

[0229]

[0230] Compound (6) was obtained in the same manner as in Synthesis Example 1, except that 4-aminobenzonitrile (manufactured by Tokyo Chemical Industry Co., Ltd.) was used in place of 4-methylsulfonylaniline in a 2.5 molar equivalent relative to compound (1). The results of its NMR measurements are shown below.

[0231] 1 HNMR (500MHz, HFIP-d2): 8.93 (s, 4H), 8.77 (dm, 4H), 7.55 (dm, 4H)

[0232] [Fabrication and Evaluation of Organic Thin Films and Photoelectric Conversion Devices]

[0233] In the following examples and comparative examples, the organic thin film and photoelectric conversion element were fabricated using an evaporation deposition machine, and the applied current and voltage were measured under atmospheric conditions. The fabricated photoelectric conversion element was placed in a measurement chamber, and the applied current and voltage were measured. The applied current and voltage were measured using an automatic IV measuring machine (manufactured by SYSTEM GIKEN Co., Ltd.). Light irradiation was performed using a light source device (manufactured by Asahi Spectrophotometer Co., Ltd., product name (PVL-3300)) under conditions of an irradiation wavelength of 550 nm and an irradiation half-width of 20 nm. The brightness-darkness ratio was obtained by dividing the current value during illumination by the current value in the dark.

[0234] [Example 1]

[0235] Boron phthalocyanine chloride (purified product manufactured by Sigma-Aldrich, purity >99%) was vacuum-deposited at a thickness of 100 nm on ITO transparent conductive glass (ITO manufactured by GEOMATEC Co., Ltd., thickness 100 nm) as a photoelectric conversion layer. A sublimated purified tris(8-hydroxyquinoline) aluminum (Alq3) (manufactured by Tokyo Chemical Industry) was deposited at a thickness of 25 nm on top of this layer via resistance heating vacuum evaporation as auxiliary layer 1. Then, compound (2) was deposited at a thickness of 25 nm on top of this layer via resistance heating vacuum evaporation as auxiliary layer 2. Next, aluminum was vacuum-deposited at a thickness of 100 nm on auxiliary layer 2 to form an electrode, thus obtaining a photoelectric conversion element.

[0236] For the obtained photoelectric conversion element, ITO and aluminum were used as electrodes and a voltage of 4V was applied. The current values ​​in the dark and under light were measured. The brightness ratio was calculated from the measurement results. The results are shown in Table 1. It should be noted that the dark current value is expressed as a relative value when the value in Comparative Example 1 described later is set to 1.

[0237] (Example 2)

[0238] Using compound (3) instead of compound (2), a single-layer organic thin film and a photoelectric conversion element were fabricated in the same manner as in Example 1. The resulting photoelectric conversion elements were evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0239] (Example 3)

[0240] Using compound (4) instead of compound (2), a single-layer organic thin film and a photoelectric conversion element were fabricated in the same manner as in Example 1. The resulting photoelectric conversion elements were evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0241] (Example 4)

[0242] Using compound (7) instead of compound (2), a single-layer organic thin film and a photoelectric conversion element were fabricated in the same manner as in Example 1. The resulting photoelectric conversion elements were evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0243] (Example 5)

[0244] Using compound (8) instead of compound (2), a single-layer organic thin film and a photoelectric conversion element were fabricated in the same manner as in Example 1. The resulting photoelectric conversion elements were evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0245] (Example 6)

[0246] Using compound (9) instead of compound (2), a single-layer organic thin film and a photoelectric conversion element were fabricated in the same manner as in Example 1. The resulting photoelectric conversion elements were evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0247] (Example 7)

[0248] Using compound (10) instead of compound (2), a single-layer organic thin film and a photoelectric conversion element were fabricated in the same manner as in Example 1. The resulting photoelectric conversion elements were evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0249] (Example 8)

[0250] Using compound (11) instead of compound (2), a single-layer organic thin film and a photoelectric conversion element were fabricated in the same manner as in Example 1. The resulting photoelectric conversion elements were evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0251] (Example 9)

[0252] Using compound (12) instead of compound (2), a single-layer organic thin film and a photoelectric conversion element were prepared in the same manner as in Example 1. The resulting photoelectric conversion elements were evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0253] (Comparative Example 1)

[0254] Using compound (1) instead of compound (2), a single-layer organic thin film and a photoelectric conversion element were fabricated in the same manner as in Example 1. The resulting photoelectric conversion elements were evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0255] (Comparative Example 2)

[0256] Using compound (5) instead of compound (2), a single-layer organic thin film and a photoelectric conversion element were fabricated in the same manner as in Example 1. The resulting photoelectric conversion elements were evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0257] (Comparative Example 3)

[0258] Using compound (6) instead of compound (2), a single-layer organic thin film and a photoelectric conversion element were fabricated in the same manner as in Example 1. The resulting photoelectric conversion elements were evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0259] [Table 1]

[0260]

[0261] As shown in Table 1, the photoelectric conversion element of the present invention exhibits a low dark current value, thus demonstrating excellent leakage current prevention, particularly in the dark. Specifically, the embodiments show a high brightness-to-dark ratio, resulting in even better leakage current prevention. Therefore, the compounds of the present invention are suitable as materials for photoelectric conversion elements, particularly for electron transport layers and hole blocking layers of photoelectric conversion elements.

[0262] Industrial availability

[0263] Photoelectric conversion elements, imaging elements, etc., containing the aforementioned compound (I) or compound (II) exhibit excellent leakage current protection. Therefore, the compounds, photoelectric conversion element materials, organic thin films, photoelectric conversion elements, and imaging elements of the present invention are industrially applicable in fields requiring such properties. Specifically, as solid-state imaging elements, they are industrially applicable in imaging elements used in security cameras, automotive cameras, unmanned aerial vehicle cameras, agricultural cameras, industrial cameras, medical cameras such as endoscope cameras, game console cameras, digital cameras, digital camcorders, mobile phone cameras, and other mobile device cameras; image reading elements in fax machines, scanners, and copiers; and light sensors in biological and chemical sensors. Furthermore, as displays utilizing electroluminescence, they are industrially applicable in television monitors, touch monitors, digital signage, wearable displays, electronic paper, and head-up displays for mobile applications.

[0264] Explanation of reference numerals in the attached figures

[0265] 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. The compound represented by the following formula (I), R1 and R2 are hydrogen atoms, and R3, R4, R5, R6 and R7 are each independently selected from the group consisting of hydrogen atoms, halogen atoms, hydroxyl groups, mercapto groups, amino groups, cyano groups, carboxyl groups, nitro groups, 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, carboxylamide groups, alkoxycarbonyl groups, aryloxycarbonyl groups, acyl groups and monovalent heterocyclic groups, and any adjacent R3, R4, R5 and R6 are optionally part of a fused aliphatic ring or a fused aromatic ring, which optionally contains one or more atoms other than carbon.

2. The compound represented by formula (II) below, R1 and R2 are hydrogen atoms, and R8 is selected from the group consisting of hydrogen atoms, halogen atoms, hydroxyl groups, mercapto groups, amino groups, carboxyl groups, nitro groups, and optionally substituted straight-chain, branched, or cyclic alkyl groups, thioalkyl groups, thioaryl groups, aryloxy groups, alkylamino groups, arylamino groups, alkoxy groups, acylamino groups, acyloxy groups, aryl groups, carboxylamide groups, alkoxycarbonyl groups, aryloxycarbonyl groups, acyl groups, and monovalent heterocyclic groups. 10 and R 11 Each of the following groups is independently selected from the group consisting of hydrogen atom, halogen atom, hydroxyl group, mercapto group, amino group, cyano group, carboxyl group, nitro group, and optionally substituted straight-chain, branched, or cyclic alkyl, thioalkyl, thioaryl, arylsulfonyl, aryloxy, alkylsulfonyl, alkylamino, arylamino, alkoxy, acylamino, acyloxy, aryl, carboxylamide, alkoxycarbonyl, aryloxycarbonyl, acyl, and monovalent heterocyclic groups, and any adjacent R8, R9, R 10 and R 11 Optionally, it is part of a fused aliphatic ring or a fused aromatic ring, wherein the fused aliphatic ring and the fused aromatic ring optionally contain one or more atoms other than carbon.

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

4. The compound according to claim 1 or 2, wherein the energy difference between the lowest unoccupied molecular orbital and the highest occupied molecular orbital obtained by density functional theory is greater than 3.00 eV and less than 4.00 eV.

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

6. An organic thin film comprising the compound of claim 1 or 2.

7. The organic thin film according to claim 6, wherein it has a maximum absorption wavelength of light absorption band below 450 nm.

8. 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 comprises the material for photoelectric conversion elements as described in claim 5.

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 comprises the organic thin film as described in claim 6.

10. The photoelectric conversion element according to claim 9, wherein, The photoelectric conversion film comprises a photoelectric conversion layer and an auxiliary layer. The auxiliary layer may consist solely of the organic thin film, or may consist of multiple films comprising the organic thin film.

11. A camera element comprising the photoelectric conversion element of claim 9.

12. The imaging element according to claim 11 is formed by stacking two or more of the photoelectric conversion elements.

13. A camera element comprising an array of a plurality of photoelectric conversion elements as described in claim 9.

14. A light sensor comprising the imaging element of claim 11.

15. A solid-state camera device comprising the camera element of claim 11.

Images