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

Abstract

A compound represented by formula (1) (R1 to R4 each independently represent a hydrogen atom, a halogen atom, a linear, branched or cyclic alkyl group, or the like). # imgabs0 #

Description

Technical Field

[0001] The present invention relates to a compound, an organic thin film, a photoelectric conversion element, an imaging element, a photosensor, and a solid-state imaging device. Background Art

[0002] In the past, it is known that the technology of photoelectrically converting visible light into an electrical signal is used, for example, in an imaging element. Such an imaging element is provided in a solid-state imaging device such as a CCD (Charge Coupled Device) image sensor and a CMOS (Complementary Metal Oxide Semiconductor) image sensor. In recent years, in solid-state imaging devices, as the pixel size is reduced, organic photoelectric conversion films for responding to this have been studied. For example, Patent Documents 1 and 2 disclose organic photoelectric conversion films composed of subphthalocyanine and imide.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2018-32754

[0006] Patent Document 2: Japanese Patent Application No. 2018-512423

[0007] Patent Document 3: Japanese Patent Application No. 2014-506736 Summary of the invention

[0008] Problem that the invention aims to solve

[0009] For solid-state imaging devices, high spectral selectivity and high S / N ratio are required. Therefore, it is expected that the solid-state imaging device has high external quantum efficiency (External Quantum Efficiency: EQE) and low dark current characteristics. In order to have both, there is a known method of configuring an electron transport layer and a hole blocking layer between the photoelectric conversion unit and the electrode unit, and / or configuring a hole transport layer and an electron blocking layer. Here, the electron transport layer, hole blocking layer, and electron blocking layer widely used in the field of organic electronic devices are arranged at the interface between the electrode or the conductive film and other films in the film constituting the device. These layers respectively play the role of controlling the reverse movement of holes or electrons and adjusting unnecessary hole or electron leakage. As a material for such a layer, for example, Patent Document 3 discloses an example of using naphthalene-1,4,5,8-tetracarboxylic dianhydride (NTCDA).

[0010] However, in the conventional hole blocking layer and electron blocking layer represented by the material disclosed in Patent Document 3, there is room for further improvement in suppressing the leakage current in the dark.

[0011] The object of the present invention is to provide a novel compound and photoelectric conversion element material which can suppress leakage current in dark and are particularly useful for photoelectric conversion element materials, as well as an organic thin film, a photoelectric conversion element, an imaging element, a photosensor and a solid-state imaging device containing the compound.

[0012] Solutions for solving problems

[0013] The present invention is as follows.

[0014] [1] A compound represented by the following formula (1).

[0015]

[0016] (R1, R2, R3 and R4 are each independently selected from the group consisting of a hydrogen atom, a halogen atom, a hydroxyl group, a thiol group, an amino group, a cyano group, a carboxyl group, a nitro group, and an optionally substituted linear, branched or cyclic alkyl group, a thioalkyl group, a thioaryl group, an arylsulfonyl group, an aryloxy group, an alkylsulfonyl group, an alkylamino group, an arylamino group, an alkoxy group, an acylamino group, an acyloxy group, an aryl group, a carboxamide group, an alkoxycarbonyl group, an aryloxycarbonyl group, an acyl group and a monovalent heterocyclic group, and any adjacent R1, R2, R3 and R4 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.)

[0017] [2] The aforementioned compound, wherein the lowest unoccupied orbital energy level of the compound represented by the aforementioned formula (1) obtained by density functional theory is -6.00 eV or more and -3.80 eV or less.

[0018] [3] The above compound, which is a material for a photoelectric conversion element.

[0019] [4] An organic thin film comprising the above compound.

[0020] [5] The above-mentioned organic thin film has a light absorption band with a maximum absorption wavelength below 450nm.

[0021] [6] A photoelectric conversion element comprising a first electrode film, a second electrode film, and a photoelectric conversion film located between the first electrode film and the second electrode film,

[0022] The photoelectric conversion film includes the photoelectric conversion element material.

[0023] [7] A photoelectric conversion element comprising a first electrode film, a second electrode film, and a photoelectric conversion film located between the first electrode film and the second electrode film,

[0024] The photoelectric conversion film includes the organic thin film.

[0025] [8] The above-mentioned photoelectric conversion element, wherein the above-mentioned photoelectric conversion film comprises a photoelectric conversion layer and an auxiliary layer,

[0026] The auxiliary layer is formed only of the organic thin film, or is formed of a plurality of films including the organic thin film.

[0027] [9] An imaging element comprising the above-mentioned photoelectric conversion element.

[0028]

[10] The above-mentioned imaging element is formed by stacking two or more of the above-mentioned photoelectric conversion elements.

[0029]

[11] An imaging element comprising a plurality of the above-mentioned photoelectric conversion elements arranged in an array.

[0030]

[12] A light sensor comprising the above-mentioned imaging element.

[0031]

[13] A solid-state imaging device comprising the imaging element described above.

[0032] Effects of the Invention

[0033] According to the present invention, a novel compound and a photoelectric conversion element material which are particularly useful as a photoelectric conversion element material, and an organic thin film, a photoelectric conversion element, an imaging element, a photosensor, and a solid-state imaging device containing the compound can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic cross-sectional view partially showing an example of the photoelectric conversion element of the present invention. DETAILED DESCRIPTION

[0035] Hereinafter, the mode for implementing the present invention (hereinafter referred to as "the present embodiment") will be described in detail with reference to the accompanying drawings as needed, but the present invention is not limited to the present embodiment described below. The present invention can be modified in various ways without departing from the main purpose thereof. It should be noted that in the accompanying drawings, the same symbols are marked for the same elements, and repeated descriptions are omitted. In addition, unless otherwise specified, the positional relationships such as up, down, left, and right are based on the positional relationships shown in the accompanying drawings. Furthermore, the dimensional ratios of the accompanying drawings are not limited to the ratios shown in the drawings.

[0036] (Compound)

[0037] The compound of the present embodiment is represented by the following formula (1) (hereinafter, this compound is also referred to as "compound (1)").

[0038]

[0039] Here, R1, R2, R3 and R4 are each independently selected from the group consisting of a hydrogen atom, a halogen atom, a hydroxyl group, a thiol group, an amino group, a cyano group, a carboxyl group, a nitro group, and an optionally substituted linear, branched or cyclic alkyl group, a thioalkyl group, a thioaryl group, an arylsulfonyl group, an aryloxy group, an alkylsulfonyl group, an alkylamino group, an arylamino group, an alkoxy group, an acylamino group, an acyloxy group, an aryl group, a carboxamide group, an alkoxycarbonyl group, an aryloxycarbonyl group, an acyl group and a monovalent heterocyclic group, and any adjacent R1, R2, R3 and R4 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.

[0040] This compound (1) can suppress the leakage current in the dark, and in particular, shows excellent properties as a photoelectric conversion element material. The reason is still uncertain, but the present inventors consider it as follows. Among them, the reason is not limited to the following content. That is, compound (1) has a cyano group in the molecular structure, so that the energy level of the lowest unoccupied orbital of compound (1) decreases, and the energy level of the highest occupied orbital also decreases. As a result, compound (1) maintains a low energy level of the lowest unoccupied orbital and has a high energy gap. Thus, compound (1) can suppress the leakage current in the dark, and can obtain excellent properties as a photoelectric conversion element material.

[0041] Examples of the halogen atom include a fluorine atom (F), a chlorine atom (Cl), a bromine atom (Br), and an iodine atom (I).

[0042] The straight-chain alkyl group may be a straight-chain alkyl group having 1 to 12 carbon atoms, and examples thereof include 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.

[0043] The branched alkyl group may be a branched alkyl group having 1 to 12 carbon atoms in the alkyl group, and examples thereof include isopropyl (i-Pr), sec-butyl (s-Bu), tert-butyl (t-Bu), isopentyl, sec-pentyl, 3-pentyl, neopentyl, isohexyl, isooctyl, isononyl, isodecyl, and isododecyl. In addition, the straight-chain or branched alkyl group may have a substituent. Examples of the substituent include halogen atoms such as fluorine atoms, monovalent groups having aromatic rings such as benzyl, naphthyl, and phenoxy groups, monovalent groups having heteroatoms such as alkoxy groups, aminoalkyl groups, and thioalkyl groups, monovalent groups having heterocycles such as pyridyl groups, hydroxyl groups, carboxyl groups, amino groups, and thiol groups.

[0044] The cyclic alkyl group may be a cyclic alkyl group having 3 to 10 carbon atoms in the alkyl group, for example, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group. In addition, the cyclic alkyl group may have heteroatoms such as nitrogen atoms, oxygen atoms, and sulfur atoms in its ring. As such a cyclic alkyl group, for example, a pyrrolidinyl group, an oxazolidinyl group, a pyrazolidinyl group, a thiazolidinyl group, an imidazolidinyl group, a dioxofuranyl group, a tetrahydrofuranyl group, a tetrahydrothienyl group, a piperazinyl group, a dioxane group, and a morpholinyl group. Furthermore, a monovalent group such as a hydroxyl group, a carboxyl group, an amino group, and a thiol group may be bonded to the cyclic alkyl group.

[0045] As the thioalkyl group (—SR; hereinafter, R represents an alkyl group) and the thioaryl group (—SAr; hereinafter, Ar represents an aryl group), 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 may be mentioned. In addition, the thioalkyl group and the thioaryl group may have a substituent such as an amino group, a hydroxyl group, a halogen atom, an alkoxy group, or a thioalkyl group. Examples of such thioalkyl groups and thioaryl groups include methylthio, ethylthio, phenylthio, tolylthio, aminophenylthio, hydroxyphenylthio, fluorophenylthio, dimethylphenylthio, and methylthiophenylthio.

[0046] The arylsulfonyl group (-SO2-Ar) may be an arylsulfonyl group having 6 to 16 carbon atoms in the aryl group, and examples thereof include benzenesulfonyl, toluenesulfonyl, dimethylbenzenesulfonyl, mesitylenesulfonyl, octylbenzenesulfonyl and naphthylsulfonyl.

[0047] The aryloxy group (—O—Ar) may be an aryloxy group having 6 to 16 carbon atoms in the aryl group. The aryloxy group may have a substituent such as a cyano group, a halogen atom such as a fluorine atom, a hydroxyl group, an alkoxy group such as a methoxy group, an amino group, an alkylamino group, a thiol group, or an aryloxy group. Examples of such an aryloxy group include a phenoxy group, a cyanophenoxy group, a methylcyanophenoxy group, a dimethylcyanophenoxy group, a fluorocyanophenoxy group, a dicyanophenoxy group, a methoxycyanophenoxy group, a tricyanophenoxy group, a cyanonaphthyloxy group, a dicyanonaphthyloxy group, a 2-methylphenoxy group, a 3-methylphenoxy group, a 4-methylphenoxy group, a fluoromethylphenoxy group, a dimethylphenoxy group, a 3-hydroxyphenoxy group, a fluoro-3-hydroxyphenoxy group, a 2-hydroxyphenoxy group, a fluoro-2-hydroxyphenoxy group, a methoxyphenoxy group, an ethoxyphenoxy group, a fluorophenoxy group, a perfluorophenoxy group, a dimethoxyphenoxy group, an aminophenoxy group, an N,N-dimethylaminophenoxy group, a thiophenoxy group, a (trifluoromethyl)phenoxy group, a naphthyloxy group, a methoxynaphthyloxy group, a fluoronaphthyloxy group, and a phenoxyphenoxy group.

[0048] The alkylsulfonyl group (—SO 2 —R) may be an alkylsulfonyl group having 1 to 12 carbon atoms in the alkyl group, and examples thereof include a methylsulfonyl group, an ethylsulfonyl group, and an n-butylsulfonyl group.

[0049] The alkylamino group (herein, the alkylamino group is -NHR or -NR2, and two R's may be the same as or different from each other) may be an alkylamino group having 1 to 12 carbon atoms in the alkyl group, for example, 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.

[0050] As the arylamino group (here, the arylamino group is -NHAr or -NAr2, and the two Ar's may be the same as or different from each other), it may be an arylamino group having 6 to 16 carbon atoms, for example, anilino, toluidinyl, dimethylaniline, isopropylaniline, tert-butylaniline, fluoroaniline, trifluoromethylaniline, bis(trifluoromethyl)aniline, pyridylamino, methylpyridylamino, fluoropyridylamino, pyrimidinylamino and biphenylamino.

[0051] The alkoxy group (-OR) may be an alkoxy group having 1 to 12 carbon atoms, for example, a methoxy group, an ethoxy group, an n-propoxy group, an n-butoxy group, an n-pentoxy group, an n-hexyloxy group, an n-heptyloxy group, an n-octyloxy group, an n-nonyloxy group, an n-decyloxy group, an n-dodecyloxy group, an isopropoxy group, a sec-butoxy group, a tert-butoxy group, an isopentyloxy group, a sec-pentyloxy group, a 3-pentyloxy group, a neopentyloxy group, an isohexyloxy group, an isooctyloxy group, an isononyloxy group, an isodecyloxy group and an isododecyloxy group.

[0052] The acylamino group (-NH-COR or -NH-COAr) may have 1 to 12 carbon atoms in the alkyl group or 6 to 16 carbon atoms in the aryl group, and may have a halogen atom such as a fluorine atom, an alkoxy group, or a substituent such as a cyano group. Examples of such acylamino groups include acetylamino, propionylamino, benzylamino, methylbenzylamino, dimethylbenzylamino, methoxybenzylamino, cyanobenzylamino, and bis(trifluoromethyl)benzylamino.

[0053] As the acyloxy group (-O-COR or -O-COAr), the number of carbon atoms in the alkyl group may be 1 to 12 or the number of carbon atoms in the aryl group may be 6 to 16. The acyloxy group may further have a halogen atom such as a fluorine atom and a substituent such as a cyano group, and may have a heteroatom such as a nitrogen atom in the aromatic ring. Examples of such acyloxy groups include benzoyloxy, methylbenzoyloxy, dimethylbenzoyloxy, cyanobenzoyloxy, fluorobenzoyloxy, bis(trifluoromethyl)benzoyloxy, pyridinecarboxyl, and methylpyridinecarboxyl.

[0054] The aryl group (-Ar) may be an aryl group having 6 to 16 carbon atoms. The aryl group may further have a substituent such as an amino group, a hydroxyl group, a thiol group, a halogen atom such as a fluorine atom, a nitro group, and a cyano group, and may have a heteroatom such as a nitrogen atom in 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, thiophenyl, methylthiophenyl, dithiophenyl, fluorophenyl, fluoromethylphenyl, trifluoromethylphenyl, perfluorophenyl, fluoro(trifluoromethyl)phenyl, bis(trifluoromethyl)phenyl, cyanophenyl, methylcyanophenyl, dimethylcyanophenyl, dicyanophenyl, methoxycyanophenyl, tricyanophenyl, dicyanophenyl, 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, thionaphthyl, methylthionaphthyl, dithionaphthyl, fluoronaphthyl, trifluoromethylnaphthyl, perfluoronaphthyl, di(trifluoromethyl)naphthyl, biphenyl, cyanobiphenyl.

[0055] As the carboxamide group (herein, the carboxamide group is -CO-NH2, -CO-NHR, -CONR2, two Rs may be the same as or different from each other, or may be -CONHAr or -CONAr2, and the two Ars may be the same as or different from each other), it may be a carboxamide group having 1 to 12 carbon atoms in the alkyl group or 6 to 16 carbon atoms in the aryl group, for example, dimethylcarboxamide group and diphenylcarboxamide group.

[0056] The alkoxycarbonyl group and the aryloxycarbonyl group (—COOR or —COOAr) may be an alkoxycarbonyl group having 1 to 12 carbon atoms in the alkyl group or 6 to 16 carbon atoms in the aryl group, and examples thereof include a methoxycarbonyl group and a phenoxycarbonyl group.

[0057] The monovalent heterocyclic group may be a monovalent heterocyclic group having 3 to 14 carbon atoms, and examples thereof include furyl, thienyl, pyrrolyl, pyrazolyl, imidazolyl, triazolyl, oxazolyl, dioxazolyl, isoxazolyl, oxadiazolyl, thiazolyl, isothiazolyl, thiadiazolyl, triazolyl, indolyl, indolyl, indolizinyl, indazolyl, indoleninyl, benzofuranyl, benzothiophenyl, carbazolyl, diphenyl pyrimidinyl, pyrazinyl, pyridazinyl, quinolinyl, isoquinolinyl, cinnolinyl, phthalazinyl, quinazolinyl, naphthyridinyl, purinyl, pteridinyl, acridinyl, phenanthridinyl, phenanthrolinyl, xanthenyl, phenoxazinyl, thianthrenyl, morpholinyl and phenazinyl.

[0058] In the compound (1) of the present embodiment, it is not particularly limited, and R1, R2, R3 and R4 are preferably independently selected from the group consisting of hydrogen atoms, halogen atoms, hydroxyl groups, thiol 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, carboxamide groups, alkoxycarbonyl groups, aryloxycarbonyl groups, acyl groups and monovalent heterocyclic groups, more preferably selected from the group consisting of hydrogen atoms, halogen atoms, nitro groups, cyano groups, and optionally substituted straight-chain, branched or cyclic alkyl groups, and particularly preferably selected from the group consisting of hydrogen atoms, halogen atoms, nitro groups, cyano groups, and alkyl groups substituted with halogen atoms. By making the compound (1) have the above structure, the leakage current in the dark can be further suppressed.

[0059] In the present embodiment, R1, R2, R3 and R4 may be the same or different. From the viewpoint of more effectively and reliably exerting the effect of the present invention, there is no particular limitation, and preferably two of R1, R2, R3 and R4 are the same, and more preferably three of R1, R2, R3 and R4 are the same.

[0060] The compound (1) of this embodiment is not particularly limited. From the viewpoint of more effectively and reliably exerting the effects described in the present invention, it is preferred that at least one of R1, R2, R3 and R4 is a hydrogen atom, more preferably at least two or at least three of R1, R2, R3 and R4 are hydrogen atoms, and particularly preferably at least three of R1, R2, R3 and R4 are hydrogen atoms.

[0061] In the present embodiment, when at least two of R1, R2, R3 and R4 are hydrogen atoms, there is no particular limitation. From the viewpoint of more effectively and reliably exerting the effects described in the present invention, it is preferred that R1 and R2 are hydrogen atoms or R1 and R4 are hydrogen atoms.

[0062] The compound (1) of the present embodiment is not particularly limited, but from the viewpoint of more effectively and reliably exerting the effects of the present invention, preferably R3 and R4 are hydrogen atoms, and more preferably R2, R3 and R4 are hydrogen atoms.

[0063] In addition, when R2, R3 and R4 are hydrogen atoms, R1 is preferably selected from the group consisting of a hydrogen atom, a halogen atom, a hydroxyl group, a thiol group, an amino group, a cyano group, a carboxyl group, a nitro group, and an optionally substituted straight-chain, branched or cyclic alkyl group, a thioalkyl group, a thioaryl group, an arylsulfonyl group, an aryloxy group, an alkylsulfonyl group, an alkylamino group, an arylamino group, an alkoxy group, an acylamino group, an acyloxy group, an aryl group, a carboxamide group, an alkoxycarbonyl group, an aryloxycarbonyl group, an acyl group and a monovalent heterocyclic group, more preferably selected from the group consisting of a hydrogen atom, a halogen atom, a nitro group, a cyano group, and an optionally substituted straight-chain, branched or cyclic alkyl group, and particularly preferably selected from the group consisting of a hydrogen atom, a halogen atom, a nitro group, a cyano group, and an alkyl group substituted with a halogen atom.

[0064] From the viewpoint of more effectively and reliably exerting the effects of the present invention, the energy level of the lowest unoccupied orbital (LUMO: Lowest Unoccupied Molecular Orbital) obtained by density functional theory of the compound (1) of the present embodiment is preferably above -6.00 eV and below -3.80 eV, and more preferably above -5.50 eV and below -3.90 eV. For the compound (1) of the present embodiment, the energy level of the lowest unoccupied orbital of the compound (1) can be obtained by molecular simulation using density functional theory (e.g., molecular simulation using Gaussian, a quantum chemical calculation program manufactured by Gaussian). In addition, the energy level of the lowest unoccupied orbital obtained by density functional theory of the compound (1) of the present embodiment can be adjusted by changing R1, R2, R3 and R4. From the viewpoint of setting the energy level of the lowest unoccupied orbital to within the above range, it is preferred that at least one of R1, R2, R3 and R4 is an electron withdrawing group.

[0065] The molecular weight of the compound (1) of the present embodiment is preferably 300 or more, more preferably 350 or more, and further preferably 400 or more. If the molecular weight is 300 or more, the physical property changes caused by the thermal motion of the molecules that may be caused in the heating operation and high-temperature use environment in the manufacturing process of the organic film using the compound (1) can be further suppressed. In addition, especially when the compound (1) is formed by vacuum evaporation, the molecular weight of the compound (1) is preferably 1000 or less, more preferably 950 or less, and further preferably 900 or less. If the molecular weight is 1000 or less, the heat energy required for sublimation when the organic film of the compound (1) is formed by vacuum evaporation can be suppressed to a lower level. Thus, a good film can be formed without thermal degradation of the compound (1). However, when the film is formed by solution coating, since such a problem is not easy to occur, the molecular weight of the compound (1) can be greater than 1000.

[0066] The temperature at which the weight ratio of the weight loss of the compound (1) of this embodiment due to heating in an inert gas atmosphere becomes within 5% of that before heating (hereinafter, sometimes referred to as "5% weight loss temperature") is preferably 200°C or higher, and more preferably 250°C or higher. When the 5% weight loss temperature is 200°C or higher, changes in physical properties due to molecular thermal motion that may be caused by heating operations or high-temperature use environments in organic thin film manufacturing processes using the compound (1) can be further suppressed. The 5% weight loss temperature can be measured by differential thermal analysis.

[0067] The compound (1) of the present embodiment can be obtained by, for example, synthesizing as described later. In the product (100% by mass) obtained by synthesis, the content of the compound (1) is preferably 90% by mass or more, more preferably 93% by mass or more, and further preferably 97% by mass or more. By making the content of the compound (1) 90% by mass or more, it is possible to more effectively and reliably avoid the capture of carriers generated by undesirable impurities to impurity energy levels when the compound (1) is used in a photoelectric conversion element. As a result, the recombination of carriers can be suppressed to obtain a photoelectric conversion element with more excellent performance. For the determination of the content, liquid chromatography, gas chromatography, elemental analysis, etc. can be listed, as long as it is a known method.

[0068] Preferred combinations of R1, R2, R3 and R4 are shown below, but compound (1) is not limited to these.

[0069]

[0070]

[0071]

[0072]

[0073]

[0074] Specific examples of the compound (1) are shown below, but the compound (1) is not limited to these.

[0075]

[0076] Compound (1) can be synthesized, for example, according to the following scheme.

[0077]

[0078] More specifically, for example, a commercially available compound (α) can be imidized to obtain compound (1). For example, imidization can be performed by the method described in The Journal of Organic Chemistry, 86, 10501-10516 (2021). In addition, imidization can be performed using a compound into which R1 to R4 are introduced, or R1 to R4 can be introduced after imidization.

[0079] (Materials for photoelectric conversion elements)

[0080] The compound (1) of this embodiment can be used 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. Among them, from the viewpoint of more effectively and reliably exerting the effects described in the present invention, the compound (1) is preferably contained in an auxiliary layer, and more preferably contained in at least one of an electron transport layer and a hole blocking layer.

[0081] In addition, the compound (1) of the present embodiment can be used directly as a photosensitive material, or can be mixed with other materials and used as a photosensitive composition. The content of the compound (1) in the photosensitive composition can be 50% by mass or more relative to the total amount of the composition. In addition, its content can be 95% by mass or less, 90% by mass or less, or 80% by mass or less. The materials other than the compound (1) in the above-mentioned photosensitive composition are not particularly limited as long as they are materials generally contained in the photosensitive composition. As such materials, for example, n-type semiconductor materials, p-type semiconductor materials and light absorbing materials described later can be listed. These can be used alone or in combination of two or more.

[0082] (Organic film)

[0083] The organic film of the present embodiment comprises the compound (1) of the present embodiment or the above-mentioned photoelectric conversion element material. Such an organic film can be manufactured by a conventional dry film-forming method or a wet film-forming method. Specifically, it can be listed as: resistance heating evaporation, electron beam evaporation, sputtering and molecular lamination as vacuum processes, coating methods such as casting, spin coating, dip coating, blade coating, wire rod coating and spraying as solution processes, printing methods such as inkjet printing, screen printing, offset printing and relief printing, and soft lithography methods such as microcontact printing. Generally, for photoelectric conversion element materials, from the viewpoint of ease of processing, it is expected to be used in a process in which the compound is applied in a solution state. However, in the case of a photoelectric conversion element such as a stacked organic film, due to the risk of the coating solution corroding the underlying film, a dry film-forming method such as resistance heating evaporation is preferred.

[0084] For example, in a dry film-forming method, a composition is prepared by mixing the photoelectric conversion element material of the present embodiment and other materials corresponding to the purpose of the photoelectric conversion element as needed, and the composition is deposited on a substrate or other film under vacuum to obtain an organic thin film. In addition, in a wet film-forming method, a liquid composition is prepared by mixing the photoelectric conversion film of the present embodiment and other materials corresponding to the purpose of the photoelectric conversion element as needed with a solvent, and the composition is applied and printed on a substrate or other film, and then dried to obtain an organic thin film.

[0085] The organic film of the present embodiment may also contain materials other than the photoelectric conversion element material of the present embodiment, namely compound (1). The content of compound (1) in the organic film of the present embodiment is not particularly limited as long as it exhibits the performance required for use as a photoelectric conversion element material. For example, the content of compound (1) relative to the total amount of the organic film can be 50% by mass or more, and from the perspective 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 further preferably 95% by mass or more. The upper limit of the content of compound (1) can be 100% by mass. When the organic film of the present embodiment contains materials other than compound (1), the material is not particularly limited as long as it is generally used as a photoelectric conversion element material. As such materials, 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 called doping materials can be listed, and these can be used alone or in combination of two or more.

[0086] The thickness of the organic thin film is not particularly limited because it depends on the resistance value and charge mobility of each substance, but is usually 0.5 nm to 5000 nm, 1 nm to 1000 nm, or 5 nm to 500 nm.

[0087] From the viewpoint of more effectively and reliably exerting the effects of the present invention, the organic thin film of the present embodiment preferably has a light absorption band with a maximum absorption wavelength of 450 nm or less.

[0088] (Photoelectric conversion element)

[0089] The photoelectric conversion element of the present embodiment refers to a device that generates a charge corresponding to the amount of incident light, passes through a capacitor for accumulating the generated charge (hereinafter also referred to as an "accumulation unit"), and a transistor circuit for reading (hereinafter also referred to as a "readout unit") and outputs it to the outside of the photoelectric conversion element. Here, in the photoelectric conversion element, a photoelectric conversion film that absorbs at least a portion of the incident light is arranged between a pair of electrodes relative to each other, and light is incident on the photoelectric conversion element from above the electrodes. In addition, the photoelectric conversion film is a photosensitive film containing a material that absorbs at least a portion of the incident light in the infrared region, and holes and electrons are generated as a result of the light incidence. In addition, the photoelectric conversion element of the present embodiment may also have a photoelectric conversion element (hereinafter also referred to as an "infrared photoelectric conversion element") that generates a charge corresponding to the amount of incident light in the infrared region. Here, in the infrared photoelectric conversion element, a photoelectric conversion film that absorbs infrared light (hereinafter also referred to as an "infrared photoelectric conversion film") is arranged between a pair of electrodes relative to each other, and light is incident on the infrared photoelectric conversion element from above the electrodes. The infrared photoelectric conversion film is a photosensitive thin film containing a material that absorbs at least a portion of incident light in the infrared region (hereinafter also referred to as an "infrared absorbing material"), and holes and electrons are generated as a result of incident light.

[0090] Appropriate reference Figure 1 The photoelectric conversion element of this embodiment is described. 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 include a substrate 101 that is generally insulating on the side of the upper electrode 106 opposite to the photoelectric conversion film 110.

[0091] When the photoelectric conversion film 110 has hole transport properties or electron transport properties, the lower electrode 102 and the upper electrode 106 play the following role: taking out holes from the photoelectric conversion film 110 and trapping them, or taking out electrons and discharging them. The materials that can be used as these electrodes are not particularly limited as long as they have a certain degree of conductivity, and are preferably selected in consideration of the adhesion with the adjacent photoelectric conversion film 110, electron affinity, ionization potential and stability. As materials that can be used as electrodes, conductive metal oxides such as tin oxide (NESA), indium oxide, indium tin oxide (ITO) and indium zinc oxide (IZO) can be listed; metals such as gold, silver, platinum, chromium, aluminum, iron, cobalt, nickel and tungsten; inorganic conductive substances such as copper iodide and copper sulfide; conductive polymers such as polythiophene, polypyrrole and polyaniline; and carbon. These materials can be used alone or in combination.

[0092] The lower electrode 102 as the first electrode film includes a conductive film with light transmittance, for example, indium tin oxide (ITO). The material constituting the lower electrode 102 is not limited to ITO, and examples thereof include: tin oxide (SnO2) system materials to which dopants are added, and zinc oxide system materials to which dopants are added to zinc oxide (ZnO). As zinc oxide system materials, for example, aluminum zinc oxide (AZO) to which aluminum (Al) is added as a dopant, gallium zinc oxide (GZO) to which gallium (Ga) is added, and indium zinc oxide (IZO) to which indium (In) is added. Alternatively, as materials constituting the lower electrode 102, for example, CuI, InSbO4, ZnMgO, CuInO2, MgIN2O4, CdO, and ZnSnO3 can be listed. The thickness of the lower electrode 102 can be, for example, greater than 5 nm and less than 3000 nm, greater than 5 nm and less than 500 nm, or greater than 10 nm and less than 300 nm.

[0093] The upper electrode 106 as the second electrode film can be composed of a conductive film having light transmittance like the lower electrode 102, or can be composed of a metal such as aluminum that is generally used in the electrode of the photoelectric conversion element. In addition, in a solid-state imaging device using a solid-state imaging element as a single pixel, its upper electrode 106 can be separated according to each pixel, or can be formed as a common electrode for each pixel. The thickness of the upper electrode 106 is, for example, greater than 5nm and less than 3000nm, can be greater than 5nm and less than 500nm, or can be greater than 10nm and less than 300nm.

[0094] The conductivity of the material used for the electrodes such as the first electrode film and the second electrode film is not particularly limited as long as it does not excessively hinder the light reception of the photoelectric conversion element, but from the perspective of the signal strength and power consumption of the photoelectric conversion element, the conductivity is preferably as high as possible. For example, as a transparent electrode, if it is an ITO film with a sheet resistance value of less than 300Ω / □, it can fully function as an electrode. However, commercial products of substrates having an ITO film with a conductivity of about several Ω / □ (for example, 5 to 9Ω / □) can also be obtained, and substrates with such high conductivity are desired.

[0095] The thickness of the electrode when using the ITO film can be arbitrarily selected in consideration of conductivity, but is usually more than 5nm and less than 3000nm, preferably more than 10nm and less than 300nm. As a method for forming a film such as ITO, it can be listed: a conventionally known vapor deposition method, an electron beam method, a sputtering method, a chemical reaction method, and a coating method. The ITO film disposed on the substrate can be subjected to UV-ozone treatment or plasma treatment as required.

[0096] In addition, when stacking a plurality of photoelectric conversion films with different detected wavelengths, the electrode film used between each photoelectric conversion film must be able to transmit light of wavelengths other than the light detected by each photoelectric conversion film. From this point of view, the electrode film preferably uses a material that can transmit more than 90% of the incident light, and more preferably uses a material that can transmit more than 95% of the light. It should be noted that the above-mentioned electrode film is a film of an electrode other than the above-mentioned pair of electrodes.

[0097] In addition, when the lower part of the photoelectric conversion element in this embodiment is further provided with a visible light photoelectric conversion unit that senses infrared light or light in different visible light regions, the electrode used in the above-mentioned photoelectric conversion element preferably has a transmittance of visible light and infrared light of more than 90%, and more preferably more than 95%.

[0098] As an electrode material that meets such conditions, a transparent conductive oxide (TCO) with high transmittance to visible light and infrared light and low resistance is preferred. Although a metal thin film such as gold can be used as an electrode, if the transmittance is set to more than 90%, the resistance value will increase extremely. Therefore, TCO is preferably used as an electrode. As TCO, ITO, IZO, AZO, FTO, SnO2, TiO2 and ZnO2 are particularly preferred.

[0099] The method for forming the electrode is not particularly limited and can be appropriately selected in consideration of the compatibility with the electrode material. When using a transparent electrode, as its forming method, specifically, wet methods such as printing and coating methods, physical methods such as vacuum evaporation, sputtering and ion plating, chemical methods such as CVD and plasma CVD methods can be listed. In addition, when the electrode material is a transparent conductive metal oxide such as ITO, as its forming method, for example, electron beam method, sputtering method, resistance heating evaporation method, chemical reaction method (such as sol-gel method, etc.) and a method of applying a dispersion of the metal oxide can be listed. Furthermore, UV-ozone treatment and plasma treatment can also be implemented on transparent conductive metal oxide films such as ITO.

[0100] The photoelectric conversion film 110 may include the photoelectric conversion element material of this embodiment, or may include the above-mentioned 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 lower electrode film 102 side of the photoelectric conversion layer 104, and a second auxiliary layer 105 located on the upper electrode film 106 side of the photoelectric conversion layer 104. It should be noted that Figure 1 The photoelectric conversion film 110 shown has a first auxiliary layer 103 and a second auxiliary layer 105, but the photoelectric conversion film may also have only one of these auxiliary layers. Alternatively, the photoelectric conversion film may not have any auxiliary layer, but only have a photoelectric conversion layer 104. When the photoelectric conversion film does not have an auxiliary layer, the photoelectric conversion layer 104 is the above-mentioned organic thin film, and when the photoelectric conversion film has an auxiliary layer, at least one of the photoelectric conversion layer 104 and the auxiliary layer is the above-mentioned 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 above-mentioned organic thin film containing the material for the photoelectric conversion element of this embodiment.

[0101] The photoelectric conversion layer 104 may be an organic semiconductor film commonly used as a photoelectric conversion layer, or may be the above-mentioned organic thin film. In addition, in the photoelectric conversion layer 110, these organic semiconductor films and organic thin films may be one layer or multiple layers. When it is one layer, a p-type organic semiconductor film, an n-type organic semiconductor film, or a mixed film thereof (hereinafter referred to as a "bulk heterojunction structure") is used. On the other hand, when it is a multilayer, the number of layers may be about 2 to 10 layers, and it may be a structure in which any of p-type organic semiconductor films, n-type organic semiconductor films, or mixed films thereof (hereinafter referred to as a "bulk heterojunction structure") are stacked, and a buffer layer may be inserted between the layers.

[0102] The photoelectric conversion layer 104 of the present embodiment may include the photoelectric conversion element material of the present embodiment, or may not include it, or may include materials other than the photoelectric conversion element material of the present embodiment. Wherein, when the photoelectric conversion layer 104 includes at least one of an organic p-type semiconductor, an organic n-type semiconductor, and a light absorbing material, it is preferred because the incident light energy of the desired wavelength can be more efficiently converted into an electrical signal. Wherein, for the light absorbing material, if it is an organic p-type semiconductor, it is easy to supply electrons (i.e., the ionization potential is small), or if it is an organic n-type semiconductor, it is easy to accept electrons (i.e., the electron affinity is large), because the incident light energy can be more efficiently converted into an electrical signal, it is preferred. Here, the ionization potential (HOMO level) refers to a value measured by photoelectron yield spectroscopy or photoelectron spectroscopy. In addition, the electron affinity (LUMO level) refers to the band gap value calculated from the longest wavelength absorption end of the near-infrared light spectroscopic spectrum, and the value obtained by subtracting it from the above-mentioned HOMO level, or the value measured by the reverse photoelectron spectroscopy.

[0103] When an organic semiconductor film is used, the film may be one layer or more than two layers. The organic semiconductor film may be an organic p-type semiconductor film, an organic n-type semiconductor film, a light absorbing material film, or a mixed film thereof (bulk heterojunction structure). In particular, the organic semiconductor film preferably has a bulk heterojunction junction structure layer. In such a case, by making the photoelectric conversion film contain a bulk heterojunction junction structure, the shortcoming of the short carrier diffusion length of the photoelectric conversion film can be compensated, and the photoelectric conversion efficiency can be improved.

[0104] The thickness of the photoelectric conversion layer 104 may be, for example, not less than 0.5 nm and not more than 5000 nm, not less than 1 nm and not more than 1000 nm, or not less than 5 nm and not more than 500 nm.

[0105] Hereinafter, organic semiconductors will be described in detail.

[0106] Organic p-type semiconductors are donor organic semiconductors (hereinafter also referred to as "donor organic compounds"), and mainly refer to organic compounds with the property of easily donating electrons, represented by hole transporting organic compounds. More specifically, it refers to an organic compound with a small ionization potential when two organic materials are brought into contact and used. Therefore, as a donor organic compound, any organic compound can be used as long as it is an organic compound with electron donating properties.

[0107] As such donor organic compounds, for example, triarylamine compounds, benzidine compounds, pyrazoline compounds, styrylamine compounds, hydrazone compounds, triphenylmethane compounds, carbazole compounds, polysilane compounds, thiophene compounds, phthalocyanine compounds, cyanine compounds, merocyanine compounds, oxonol compounds, polyamine compounds, indole compounds, pyrrole compounds, pyrazole compounds, polyarylene compounds, condensed aromatic carbocyclic compounds (such as naphthalene derivatives, anthracene derivatives, phenanthrene derivatives, tetracene derivatives, pyrene derivatives, perylene derivatives, and fluoranthene derivatives), and metal complexes having nitrogen-containing heterocyclic compounds as ligands. It should be noted that the present invention is not limited to these. As mentioned above, any organic compound having an ionization potential smaller than that of an organic compound used as an acceptor organic compound can be used as a donor organic semiconductor.

[0108] An organic n-type semiconductor refers to an acceptor organic semiconductor (hereinafter also referred to as an "acceptor organic compound"), which mainly refers to an organic compound having the property of easily accepting electrons, represented by an electron transporting organic compound. More specifically, it refers to an organic compound having a large electron affinity when two organic compounds are brought into contact. Therefore, as an acceptor organic compound, any organic compound can be used as long as it is an organic compound with electron accepting properties.

[0109] Examples of such acceptor organic compounds include condensed aromatic carbocyclic compounds (e.g., naphthalene derivatives, anthracene derivatives, phenanthrene derivatives, tetracene derivatives, pyrene derivatives, perylene derivatives, fluoranthene derivatives, and fullerene derivatives), 5- to 7-membered heterocyclic compounds containing nitrogen atoms, oxygen atoms, and sulfur atoms (e.g., pyridine, pyrazine, pyrimidine, pyridazine, triazine, quinoline, quinoxaline, quinazoline, phthalazine, cinnoline, isoquinoline, pteridine, acridine, phenazine, and phenanthroline); , tetrazole, pyrazole, imidazole, thiazole, oxazole, indazole, benzimidazole, benzotriazole, benzoxazole, benzothiazole, carbazole, purine, triazolopyridazine, triazolopyrimidine, tetraazaindene, oxadiazole, imidazopyridine, pyrrolidine, pyrrolopyridine, thiadiazopyridine, dibenzoazepine and tribenzoazepine), polyarylene compounds, fluorene compounds, cyclopentadiene compounds, silyl compounds, and metal complexes having nitrogen-containing heterocyclic compounds as ligands. It should be noted that the present invention is not limited to these. As mentioned above, any organic compound having an electron affinity higher than that of an organic compound used as a donor organic compound can be used as an acceptor organic semiconductor.

[0110] The light absorbing material is a compound having a maximum light absorption wavelength in the visible light region, particularly in the range of 450 nm to 650 nm. It is desirable that the absorption intensity of the light absorbing material at the maximum light absorption wavelength is greater than the absorption intensity of the donor organic compound or the acceptor organic compound at the maximum light absorption wavelength. By having such an absorption intensity, incident light can be selectively absorbed at the maximum light absorption wavelength of the light absorbing material. After the incident light is absorbed by the light absorbing material and the photons are converted into excitons, exciton separation occurs at the interface between the donor organic compound and the acceptor organic compound, thereby efficiently generating carriers of holes and electrons.

[0111] As such a light absorbing material, a compound generally called a pigment can be used. For example, phthalocyanine derivatives, subphthalocyanine derivatives, quinacridone derivatives, porphyrin derivatives, naphthalene or perylene derivatives, phthalapyrene derivatives, styryl derivatives, cyanine derivatives, hemicyanine derivatives, merocyanine derivatives, rhodacyanine derivatives, oxonol derivatives, hemioxonol derivatives, croconium derivatives, squarylium derivatives, azamethine derivatives, arylene derivatives, azo derivatives, azomethine derivatives, metallocene derivatives, fulgide derivatives, phenazine derivatives, phenothiazine derivatives, polyene derivatives, acridine derivatives, acridone derivatives, diphenylamine derivatives, triphenylamine, triarylamine derivatives such as naphthylamine and styrylamine, quinophthalone derivatives, phenoxazine derivatives, chlorophyll derivatives, rhodamine derivatives, diphenylmethane or triphenylmethane derivatives, xanthene derivatives acridine derivatives, phenoxazine derivatives, quinoline derivatives, oxazine derivatives, thiazine derivatives, quinone derivatives, benzoquinone derivatives, naphthoquinone derivatives, anthraquinone derivatives, indigo or thioindigo derivatives, pyrrole derivatives, pyridine derivatives, dipyrromethene derivatives, indole derivatives, diketopyrrolopyrrole derivatives, coumarin derivatives, fluorene derivatives, fluorenone derivatives, fluoranthene derivatives, anthracene derivatives, pyrene derivatives, carbazole derivatives, phenylenediamine derivatives, benzidine derivatives, phenanthroline derivatives, imidazole derivatives, oxazoline derivatives, thiazoline derivatives, triazole derivatives, thiadiazole derivatives, oxazole derivatives, thiazole derivatives, oxadiazole derivatives, thiophene derivatives, selenophene derivatives, silole derivatives, germole derivatives, stilbene derivatives, phenylenevinylene derivatives, pentacene derivatives, rubrene derivatives, thienothiophene derivatives, benzodithiophene derivatives, xanthene-xanthene derivatives and fullerene derivatives. It should be noted that the present invention is not limited to these. As mentioned above, any compound having an absorption intensity greater than the absorption intensity of the donor organic compound or the acceptor organic compound at the maximum light absorption wavelength can be used as a light absorbing material. In addition, the light absorbing material can also have the function of serving as a donor organic compound or an acceptor organic compound.

[0112] The first auxiliary layer 103 includes, for example, at least one of a hole blocking layer and an electron transport layer. When the first auxiliary layer 103 includes both of them, the electron transport layer and the hole blocking layer are usually stacked in sequence from the photoelectric conversion layer 104 side. The electron transport layer plays a role in transporting electrons generated by the photoelectric conversion layer 104 to the first electrode 102, and in blocking holes from moving from the first electrode 102 at the electron transport end to the photoelectric conversion layer 104. The hole blocking layer plays a role in preventing holes from moving from the first electrode 102 to the photoelectric conversion layer 104, preventing recombination in the photoelectric conversion layer 104, reducing dark current, reducing noise and expanding the dynamic range. In addition, one layer can have the functions of both a hole blocking layer and an electron transport layer.

[0113] The second auxiliary layer 105 includes, for example, at least one of an electron blocking layer and a hole transport layer. When the second auxiliary layer 105 includes both of them, the hole transport layer and the electron blocking layer are usually stacked in sequence from the photoelectric conversion layer 104 side. The hole transport layer plays a role in transporting the generated holes from the photoelectric conversion layer 104 to the second electrode 106, and in blocking the electrons from the second electrode 106 at the hole transport end to the photoelectric conversion layer 104. The electron blocking layer plays a role in preventing electrons from moving from the second electrode 106 to the photoelectric conversion layer 104, preventing recombination in the photoelectric conversion layer 104, reducing dark current, reducing noise and expanding the dynamic range. In addition, one layer can have the functions of both the electron blocking layer and the hole transport layer.

[0114] The photoelectric conversion element material of this embodiment may also be included in any of these first auxiliary layers 103 and second auxiliary layers 105, preferably included in the first auxiliary layer 103. In the photoelectric conversion element of this embodiment, among these first auxiliary layers 103 and second auxiliary layers 105, it is preferred that the first auxiliary layer 103 includes the above-mentioned organic thin film. In addition, the photoelectric conversion element material of this embodiment is more preferably included in at least one of the hole blocking layer and the electron transport layer in the first auxiliary layer 103. In the photoelectric conversion element of this embodiment, it is preferred that at least one of the hole blocking layer and the electron transport layer is the above-mentioned organic thin film. As a result, the effects of the present invention can be more effectively and reliably exerted.

[0115] Hereinafter, materials other than the photoelectric conversion element material of the present embodiment that may be contained in each layer of the auxiliary layer will be described.

[0116] The material of the hole transport layer is not particularly limited as long as it is known as a hole transport layer in a photoelectric conversion element such as a solid-state imaging element, and examples thereof include polyaniline and doped materials thereof, and cyanide compounds described in International Publication No. 2006 / 019270.

[0117] More specifically, materials constituting the hole transport layer include, for example, selenium, iodides such as copper 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 them, as iodides, for example, copper iodide (CuI) can be listed. As layered cobalt oxides, for example, A x CoO2 (wherein 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) (PEDOT; for example, the trade name "BaytronP" manufactured by Starck V-tec), fluorene derivatives such as 2,2',7,7'-tetrakis-(N,N-di-p-methoxyphenylamine)-9,9'-spirobifluorene (spiro-MeO-TAD), carbazole derivatives such as polyvinylcarbazole, triphenylamine derivatives, diphenylamine derivatives, polysilane derivatives, and polyaniline derivatives. Furthermore, as materials for the hole transport layer, for example, there can be listed: compound semiconductors having monovalent copper such as CuInSe2 and copper sulfide (CuS), gallium phosphide (GaP), nickel oxide (NiO), cobalt oxide (CoO), iron oxide (FeO), bismuth oxide (Bi2O3), molybdenum oxide (MoO2) and chromium oxide (Cr2O3).

[0118] Furthermore, if the hole transport layer has a higher LUMO level than the photoelectric conversion film, it is preferred because it can provide an electron blocking function having a rectifying effect that inhibits electrons generated in the photoelectric conversion film from moving toward the electrode side. Such a hole transport layer is also called an electron blocking layer.

[0119] Among the materials constituting the electron blocking layer, examples of low molecular weight organic compounds include aromatic diamine compounds such as N,N'-bis(3-methylphenyl)-(1,1'-biphenyl)-4,4'-diamine (TPD) and 4,4'-bis[N-(naphthyl)-N-phenylamino]biphenyl (α-NPD), oxazole, oxadiazole, triazole, imidazole, imidazolones, stilbene derivatives, pyrazoline derivatives, tetrahydroimidazole, polyarylalkane, butadiene, 4,4',4"-tris(N-(3-methylphenyl)N-phenylamino)triphenylamine (m-MTDATA), porphyrin, copper tetraphenylporphyrin, phthalocyanine, copper phthalocyanine, and porphyrin compounds such as titanium phthalocyanine, triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, Amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives and silazane derivatives. In addition, as high molecular organic compounds, for example, polymers of phenylene vinylene, fluorene, carbazole, indole, pyrene, pyrrole, methylpyridine, thiophene, acetylene and diacetylene and their derivatives can be listed. Even if it is not an electron-donating compound, as long as it is a compound with sufficient hole transport properties, it can be used as a material constituting the electron blocking layer. Furthermore, among the materials constituting the electron blocking layer, as inorganic compounds, for example, calcium oxide, chromium oxide, copper chromium oxide, manganese oxide, cobalt oxide, nickel oxide, copper oxide, gallium copper oxide, strontium copper oxide, niobium oxide, molybdenum oxide, indium copper oxide, indium silver oxide and metal oxides such as indium oxide, selenium, tellurium and antimony sulfide can be listed. These can be used alone or in combination of two or more.

[0120] 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 to 300 nm, more preferably 30 nm to 250 nm, and even more preferably 50 nm to 200 nm.

[0121] The method for forming the hole transport layer and the electron blocking layer can be a known one in the past, and can be any of a dry film-forming method such as a vacuum evaporation method and a wet film-forming method such as a solution coating method, but from the viewpoint that the coating surface can be leveled, a wet film-forming method is preferably used. As a dry film-forming method, for example, a evaporation method such as a vacuum evaporation method and a sputtering method can be listed. The evaporation can be any of physical vapor deposition (PVD) and chemical vapor deposition (CVD), but preferably physical vapor deposition such as vacuum evaporation. As a wet film-forming method, for example, an inkjet method, a spray method, a nozzle printing method, a spin coating method, a dip coating method, a casting method, a die coating method, a roller coating method, a rod coating method, and a gravure coating method can be listed.

[0122] The material constituting the electron transport layer is not particularly limited as long as it is known as an electron transport layer in a photoelectric conversion element such as a solid-state imaging element, and examples thereof include: octaazaporphyrin, and perfluorinated bodies of p-type semiconductors (such as perfluoropentacene, perfluorophthalocyanine, etc.), fullerenes, fullerene derivatives (such as [6,6]-phenyl-C61-butyric acid methyl ester; PCBM, etc.), organic compounds such as perylene, indenoindene and indenoindene derivatives, 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.) Inorganic oxides. The electron transport layer may be porous or dense, and when stacking them, it is preferred to stack the porous electron transport layer and the dense electron transport layer in this order from the photoelectric conversion film side.

[0123] Furthermore, if the electron transport layer has a HOMO level lower than that of the photoelectric conversion film, it is preferred because it can be provided with a hole blocking function having a rectifying effect that prevents holes generated in the photoelectric conversion film from moving toward the counter electrode. Such an electron transport layer is also called a hole blocking layer.

[0124] Examples of materials constituting the hole blocking layer include oxadiazole derivatives such as 1,3-bis(4-tert-butylphenyl-1,3,4-oxadiazolyl)benzene (OXD-7), anthraquinone dimethane derivatives, diphenylquinone derivatives, bathocuproine, bathophenanthroline and their derivatives, triazine compounds, triazole compounds, tris(8-hydroxyquinoline)aluminum complex, bis(4-methyl-8 -quinoline) aluminum complex, silole compounds, porphyrin compounds, DCM (4-dicyano-methylene-2-methyl-6-(4-(dimethylaminophenylvinyl))-4H pyran) and other styrene compounds, naphthalenetetracarboxylic anhydride (NTCDA), naphthalenetetracarboxylic acid diimide, perylenetetracarboxylic anhydride (PTCDA), perylenetetracarboxylic acid diimide and other n-type semiconductor materials, titanium oxide, zinc oxide and gallium oxide and other n-type inorganic oxides, and lithium fluoride, sodium fluoride and cesium fluoride and other alkali metal fluorides. Furthermore, those doped with alkali metal compounds in organic semiconductor molecules have the function of improving the electrical connection with the opposing electrode, so they are preferred. These can be used alone or in combination of two or more.

[0125] 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 to 300 nm, more preferably 30 nm to 250 nm, and even more preferably 50 nm to 200 nm.

[0126] As a method for forming an electron transport layer and a hole blocking layer, it can be a method known in the past, and it can be any of a dry film-forming method such as a vacuum evaporation method and a wet film-forming method such as a solution coating method, but from the viewpoint that the coating surface can be leveled, a wet film-forming method is preferably used. As a dry film-forming method, for example, a evaporation method such as a vacuum evaporation method and a sputtering method can be listed. The evaporation can be any of physical evaporation (PVD) and chemical evaporation (CVD), but physical evaporation such as vacuum evaporation is preferred. As a wet film-forming method, for example, an inkjet method, a spray method, a nozzle printing method, a spin coating method, a dip coating method, a casting method, a die coating method, a roller coating method, a rod coating method, and a gravure coating method can be listed.

[0127] The photoelectric conversion element of this embodiment may have a single layer or two or more auxiliary layers different from the first auxiliary layer 103 between the first auxiliary layer 103 and the lower electrode 102. As such an auxiliary layer, for example, there can be listed: a hole injection layer that improves the hole injection property from the lower electrode 102 to the first auxiliary layer 103. As materials constituting the hole injection layer, for example, there can be listed: phthalocyanine derivatives, starburst amines such as m-MTDATA (4,4',4"-tri[phenyl(m-tolyl)amino]triphenylamine), polythiophenes such as PEDOT (poly(3,4-ethylenedioxythiophene)), and polymer materials such as polyvinylcarbazole derivatives. The thickness of the auxiliary layer may be the same as that of the first auxiliary layer 103.

[0128] The photoelectric conversion element of this embodiment may have a single layer or two or more auxiliary layers different from the second auxiliary layer 105 between the second auxiliary layer 105 and the upper electrode 106. As such an auxiliary layer, for example, an electron injection layer and an electron transport layer that improve the electron injection property from the upper electrode 106 to the second auxiliary layer 105 can be listed. As materials constituting the electron injection layer, for example, metals such as cesium, lithium and strontium, and lithium fluoride can be listed. As materials constituting the electron transport layer, it can be the same as above. In addition, the thickness of the auxiliary layer can be the same as that of the second auxiliary layer 105.

[0129] The photoelectric conversion element of the present embodiment may include, in addition to the above-mentioned layers, at least one of an interlayer contact improving layer and a crystallization preventing layer located between these layers.

[0130] The interlayer contact improvement layer has the following function: it reduces the damage to the film closest to the lower part, such as the photoelectric conversion film 110, during the film formation of the upper electrode 106. In particular, if the high-energy particles present in the device used for the film formation of the upper electrode 106 are sputtered, for example, the sputtered particles or secondary electrons, Ar particles, oxygen anions, etc. collide with the film closest to the lower part and deteriorate, and sometimes performance degradation such as increased leakage current and reduced sensitivity occurs. As a method to prevent this, it is preferred to set an interlayer contact improvement layer on the upper layer of the film closest to the lower part. The material of the interlayer contact improvement layer is preferably organic substances such as copper phthalocyanine, NTCDA, PTCDA, [dipyrazino [2,3-F: 2', 3'-H] quinoxaline-2,3,6,7,10,11-hexacarbonitrile] (HATCN), acetylacetonate complex, BCP, etc., organic-metal compounds, or inorganic substances 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., but is preferably greater than 2 nm and less than 500 nm from the perspective of selecting a material that does not absorb in the visible light region or using it at a thinner thickness.

[0131] As described above, the photoelectric conversion element of this embodiment is connected to a capacitor for accumulating the generated charge, i.e., an accumulation unit, and a transistor circuit for reading out, i.e., a readout unit, via a connection unit formed of a conductive material. In addition, the photoelectric conversion element includes a protective structure such as a protective film to avoid external air, a substrate for maintaining strength, and a microlens for focusing light, etc., as needed.

[0132] A readout unit is provided to read out a signal corresponding to the charge generated in the photoelectric conversion film. The readout unit is composed of, for example, a CCD, a CMOS circuit or a TFT circuit, and is preferably shielded from light by a light shielding layer disposed in the insulating layer. The readout circuit is electrically connected to the electrode corresponding thereto via a connecting unit. It should be noted that, in order to ensure the amount of charge required for reading, an accumulation unit composed of a capacitor or the like may also be sandwiched between the electrode and the connecting unit. The connecting unit is buried in the insulating layer and is a plug or the like for electrically connecting an electrode (for example, a transparent electrode or an opposing electrode) to the readout unit. When the component thus constructed is a solid-state imaging element, if light is incident, the light is incident on the photoelectric conversion film and a charge is generated there. The electrons in the generated charge are captured (and accumulated) by one electrode, and the holes are captured by another electrode. A voltage signal corresponding to the amount is output to the outside of the solid-state imaging element through the readout unit.

[0133] (Image capture element)

[0134] If the imaging element of this embodiment includes the photoelectric conversion element of this embodiment, the other configurations may be the same as those of the conventional imaging element. For example, the imaging element of this embodiment may be provided with a plurality of photoelectric conversion elements of this embodiment in an array. That is, by arranging a plurality of photoelectric conversion elements in an array, a solid-state imaging element is formed that shows incident position information in addition to the amount of incident light.

[0135] The imaging element of the present embodiment may have one photoelectric conversion element of the present embodiment, or may be stacked with two or more. In the case where two or more photoelectric conversion elements of the present embodiment are stacked, each photoelectric conversion element can selectively detect light of different wavelength bands and perform photoelectric conversion. For example, in the case where three or more photoelectric conversion elements of the present embodiment are stacked, at least one can obtain a green signal, at least one can obtain a blue signal, at least one can obtain a red signal, and at least one can obtain an infrared light color signal. Thus, the imaging element can obtain multiple color signals in one pixel without using a color filter. In addition, color signals other than the color signals detected by the photoelectric conversion element of the present embodiment can also be sensed by a device having a silicon photodiode known in the past.

[0136] In the imaging element, when a photoelectric conversion element arranged closer to the light source does not shield (i.e. transmits) the absorption wavelength of another photoelectric conversion element arranged behind it when viewed from the light source side, a device having multiple photoelectric conversion elements and silicon photodiodes may be stacked.

[0137] In the imaging element, from the viewpoint of easy molding, a part of the photoelectric conversion element may be configured as a thin film on the same plane without structural partitions between adjacent photoelectric conversion elements.

[0138] The imaging element of this embodiment may further include a substrate. The substrate is used to stack various layers thereon to manufacture the imaging element, or to improve the mechanical strength of the imaging element. The type of substrate is not particularly limited, and examples thereof include semiconductor substrates, glass substrates, and plastic substrates.

[0139] (Light Sensor)

[0140] The optical sensor of this embodiment only needs to include the imaging element of this embodiment, and other configurations may be the same as those of conventional optical sensors. The optical sensor can receive light in the imaging element of this embodiment and output an electrical signal corresponding to the amount of light received.

[0141] (Solid-state imaging device)

[0142] The solid-state imaging device of this embodiment only needs to include the imaging element of this embodiment, and the other configurations may be the same as those of the conventional solid-state imaging device. The solid-state imaging device of this embodiment may be, for example, a CMOS image sensor, or may include a pixel unit as an imaging area on a semiconductor substrate, and may further include a peripheral circuit unit in the peripheral area or vertically below the pixel unit, and the peripheral circuit unit includes a row scanning unit, a horizontal selection unit, a column scanning unit, and a system control unit. The pixel unit includes the imaging element of this embodiment.

[0143] The photoelectric conversion element of the present embodiment has the following advantages by using the photoelectric conversion element material of the present embodiment. That is, the photoelectric conversion element of the present embodiment is not easy to short-circuit or generate pinholes, so the dark current value is reduced. As a result, the photoelectric conversion element of the present embodiment has excellent leakage prevention (especially in the dark). Furthermore, the photoelectric conversion element of the present embodiment tends to easily show a high light-to-dark ratio, in which case, it has more excellent leakage prevention. In addition, although the photoelectric conversion element material is not easy to aggregate in the photoelectric conversion element of the present embodiment, its hole and electron transport properties are still excellent, so the photoelectric conversion efficiency becomes higher. Furthermore, the photoelectric conversion element of the present embodiment has good heat resistance by using the photoelectric conversion element material of the present embodiment, and the durability in the manufacturing process and practical environment is improved.

[0144] Example

[0145] The present invention will be described in more detail below by way of examples, but the present invention is not limited to these examples. It should be noted that the synthesized compound can be further purified by sublimation as required.

[0146] <Synthesis example 1>

[0147]

[0148] A mixture obtained by adding 6.0 g of 1,4,5,8-naphthalenetetracarboxylic dianhydride (1) (manufactured by Tokyo Chemical Industry Co., Ltd.) and 2.6 g of 4-aminobenzonitrile (manufactured by Tokyo Chemical Industry Co., Ltd.) (1.0 molar equivalent relative to 1,4,5,8-naphthalenetetracarboxylic dianhydride (1)) to 90 mL of N,N-dimethylformamide (manufactured by Tokyo Chemical Industry Co., Ltd.) was stirred at 150°C for 8 hours. Thereafter, the mixture was cooled to room temperature and the solvent was distilled off under reduced pressure. Acetone was added to the solid obtained by distilling off the solvent, and water was slowly added while stirring, and the precipitate was filtered. After dissolving the precipitate with chloroform, sodium sulfate was added and allowed to stand for 30 minutes. Subsequently, after filtering off the sodium sulfate, the solvent was distilled off under reduced pressure. Size exclusion chromatography using chloroform as the eluent gave compound (2) as a pale yellow solid. The results of its NMR measurement are shown below.

[0149] 1 HNMR(500MHz,DMSO-d6): 8.72(dd,4H),8.07(d,2H),7.10(d,2H)

[0150] <Synthesis example 2>

[0151]

[0152] Compound (3) was obtained in the same manner as in Synthesis Example 1 except that 4-aminobenzonitrile (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of 4-aminobenzonitrile. The results of NMR measurement are shown below.

[0153] 1 HNMR (500MHz, DMSO-d6): 8.74(d,4H),8.39(d,1H),8.32(d,1H),8.10(dd,1H)

[0154] <Synthesis example 3>

[0155]

[0156] Compound (4) was obtained in the same manner as in Synthesis Example 1 except that 4-cyano-3-trifluoromethylaniline (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of 4-aminobenzonitrile. The results of NMR measurement are shown below.

[0157] 1 HNMR (500MHz, DMSO-d6): 8.73(d,4H),8.44(d,1H),8.28(d,1H),8.07(dd,1H)

[0158] <Synthesis example 4>

[0159]

[0160] A mixture of 6.0 g of 1,4,5,8-naphthalenetetracarboxylic dianhydride (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 1,4,5,8-naphthalenetetracarboxylic dianhydride (1)) and 6.6 g of 4-aminobenzonitrile (manufactured by Tokyo Chemical Industry Co., Ltd.) (2.5 molar equivalents relative to 1,4,5,8-naphthalenetetracarboxylic dianhydride (1)) was added to 90 mL of m-cresol (manufactured by Tokyo Chemical Industry Co., Ltd.) and stirred at 180°C for 8 hours. Thereafter, the mixture was cooled to room temperature, methanol was added thereto, and the precipitate was filtered. Furthermore, after washing with methanol, an aqueous potassium carbonate solution was added and stirred for 5 minutes. Subsequently, after filtering, the mixture was washed with water and methanol, and purified by sublimation to obtain compound (5) as a white solid. The results of its NMR measurement are shown below.

[0161] 1 HNMR (500MHz, HFIP-d2): 8.93 (s, 4H), 8.77 (dm, 4H), 7.55 (dm, 4H)

[0162] <Synthesis example 5>

[0163]

[0164] Compound (6) was obtained in the same manner as in Synthesis Example 1 except that aniline (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was used instead of 4-aminobenzonitrile. The results of NMR measurement are shown below.

[0165] 1 HNMR (500MHz, DMSO-d6): 8.72 (q, 4H), 7.50 (m, 5H)

[0166] <Synthesis example 6>

[0167]

[0168] Compound (7) was obtained in the same manner as in Synthesis Example 1 except that 3,5-bis(trifluoromethyl)aniline (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of 4-aminobenzonitrile. The results of NMR measurement are shown below.

[0169] 1 HNMR (500MHz, DMSO-d6): 8.75 (q, 4H), 8.34 (s, 3H)

[0170] [Production and evaluation of organic thin films and photoelectric conversion elements]

[0171] In the following embodiments and comparative examples, an organic film and a photoelectric conversion element are prepared using a vapor deposition machine, and the application of current and voltage is measured under the atmosphere. The prepared photoelectric conversion element is set in a measurement chamber, and the application of current and voltage is measured. When the application of current and voltage is measured, a semiconductor parameter analyzer (manufactured by Keithley) is used. The irradiation of the irradiation light uses a light source device (manufactured by Asahi Spectroscopy Co., Ltd., product name (PVL-3300)) under the conditions of an irradiation light wavelength of 550nm and an irradiation light half-value width of 20nm. The light-dark ratio is the value obtained by dividing the current value during light irradiation by the current value in the dark.

[0172] (Example 1)

[0173] Boron subphthalocyanine chloride (purified product manufactured by Sigma Aldrich, purity>99%) as a photoelectric conversion layer was vacuum-deposited to a thickness of 100 nm on ITO transparent conductive glass (ITO manufactured by GEOMATEC Co., Ltd., thickness 100 nm), and a sublimation purified product of tris(8-hydroxyquinoline)aluminum (Alq3) (manufactured by Tokyo Chemical Industry Co., Ltd.) was vacuum-deposited to a thickness of 25 nm as an auxiliary layer 1 thereon by resistance heating vacuum deposition. Next, compound (2) was vacuum-deposited to a thickness of 25 nm as an auxiliary layer 2 by resistance heating. Next, aluminum as an electrode was formed to a thickness of 100 nm on the auxiliary layer 2 by vacuum deposition, thereby obtaining a photoelectric conversion element.

[0174] For the obtained photoelectric conversion element, ITO and aluminum were used as electrodes and a voltage of 3 V was applied to measure the current value in the dark and the current value when irradiated with light. The light-dark ratio was calculated based on 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 of Comparative Example 1 described later is set to 1.

[0175] (Example 2)

[0176] A single-layer organic thin film and a photoelectric conversion element were prepared in the same manner as in Example 1 except that the compound (3) was used instead of the compound (2). The obtained photoelectric conversion element was evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0177] (Example 3)

[0178] A single-layer organic thin film and a photoelectric conversion element were prepared in the same manner as in Example 1 except that the compound (4) was used instead of the compound (2). The obtained photoelectric conversion element was evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0179] (Comparative Example 1)

[0180] A single-layer organic thin film and a photoelectric conversion element were prepared in the same manner as in Example 1 except that the compound (1) was used instead of the compound (2). The obtained photoelectric conversion element was evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0181] (Comparative Example 2)

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

[0183] (Comparative Example 3)

[0184] A single-layer organic thin film and a photoelectric conversion element were prepared in the same manner as in Example 1 except that the compound (6) was used instead of the compound (2). The obtained photoelectric conversion element was evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0185] (Comparative Example 4)

[0186] A single-layer organic thin film and a photoelectric conversion element were prepared in the same manner as in Example 1 except that Compound (7) was used instead of Compound (2). The obtained photoelectric conversion element was evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0187] [Table 1]

[0188]

[0189] According to the results shown in Table 1, it can be seen that the dark current value of the photoelectric conversion element of the present invention shows a low value, and therefore (especially in the dark) has a more excellent leakage prevention property. In particular, it can be seen that in some embodiments, a high light-dark ratio is shown, and a more excellent leakage prevention property is shown. In summary, it can be seen that the compound of the present invention is suitable as a material for a photoelectric conversion element, and is particularly suitable as a material included in an electron transport layer and a hole blocking layer of a photoelectric conversion element.

[0190] Industrial Applicability

[0191] By using a photoelectric conversion element material containing the compound (1) of the present invention, a photoelectric conversion element having excellent required characteristics such as hole or electron leakage prevention, transportability, and heat resistance, visible light transparency, etc. can be provided. Therefore, the compound (1), photoelectric conversion element material, organic film, and photoelectric conversion element of the present invention have industrial applicability in the field requiring such characteristics. Specifically, as a solid-state imaging element, in a medical camera such as a security camera, a vehicle-mounted camera, an unmanned aerial vehicle camera, an agricultural camera, an industrial camera, an endoscope camera, a camera for a game machine, a digital still camera, a digital video camera, a mobile phone camera, and an imaging element in a camera for a mobile device other than the above; an image reading element in a fax machine, a scanner, a copier, etc.; and an optical sensor in a biological and chemical sensor, etc., also has industrial applicability. In addition, as a display utilizing electroluminescence, it has industrial applicability in a television display, a touch display, a digital signage, a wearable display, an electronic paper, a head-up display in a mobile application, etc.

[0192] This application is based on the Japanese patent application (Japanese Patent Application No. 2023-040388) filed on March 15, 2023, the contents of which are incorporated herein by reference.

[0193] Description of Reference Numerals

[0194] 100 ...photoelectric conversion element, 101 ...substrate, 102 ...lower electrode, 103 ...first auxiliary layer, 104 ...photoelectric conversion layer, 105 ...second auxiliary layer, 106 ...upper electrode, 110 ...photoelectric conversion film.

Claims

1. A compound represented by the following formula (1): R1, R2, R3 and R4 are each independently selected from the group consisting of a hydrogen atom, a halogen atom, a hydroxyl group, a thiol group, an amino group, a cyano group, a carboxyl group, a nitro group, and an optionally substituted linear, branched or cyclic alkyl group, a thioalkyl group, a thioaryl group, an arylsulfonyl group, an aryloxy group, an alkylsulfonyl group, an alkylamino group, an arylamino group, an alkoxy group, an acylamino group, an acyloxy group, an aryl group, a carboxamide group, an alkoxycarbonyl group, an aryloxycarbonyl group, an acyl group and a monovalent heterocyclic group, and any adjacent R1, R2, R3 and R4 are optionally part of a fused aliphatic ring or a fused aromatic ring, and the fused aliphatic ring and the fused aromatic ring optionally contain one or more atoms other than carbon.

2. The compound according to claim 1, wherein The energy level of the lowest unoccupied orbital of the compound represented by the formula (1) obtained by density functional theory is -6.00 eV or more and -3.80 eV or less. The compound according to claim 1 , which is a material for a photoelectric conversion element. An organic thin film comprising the compound according to claim 1. The organic thin film according to claim 4 , which has a light absorption band with a maximum absorption wavelength of 450 nm or less.

6. A photoelectric conversion element comprising a first electrode film, a second electrode film, and a photoelectric conversion film located between the first electrode film and the second electrode film, The photoelectric conversion film comprises the photoelectric conversion element material according to claim 3 .

7. A photoelectric conversion element comprising a first electrode film, a second electrode film, and a photoelectric conversion film located between the first electrode film and the second electrode film, The photoelectric conversion film comprises the organic thin film according to claim 4.

8. The photoelectric conversion element according to claim 6 or 7, wherein: The photoelectric conversion film comprises a photoelectric conversion layer and an auxiliary layer. The auxiliary layer is formed of only the organic thin film, or is formed of a plurality of films including the organic thin film. 9 . An imaging element comprising the photoelectric conversion element according to claim 6 or 7 . 10 . The imaging element according to claim 9 , wherein two or more of the photoelectric conversion elements are stacked. 11 . An imaging element, comprising a plurality of the photoelectric conversion elements according to claim 6 or 7 arranged in an array. 12 . A photosensor comprising the imaging element according to claim 9 . 13 . A solid-state imaging device comprising the imaging element according to claim 9 .

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