Photoelectric conversion element material containing dicarbazole, organic thin film, photoelectric conversion element, and imaging element

Abstract

To provide an organic thin film for use in a photoelectric converter by utilizing a photoelectric converter material with a deep HOMO level and excellent heat resistance, and thus provide various photoelectric converters, particularly an imager, employing the organic thin film, and an optical sensor employing the same.SOLUTION: A photoelectric converter material comprises a compound having a dicarbazole ring represented by the general formula (1) in the figure, where X represents an oxygen atom or sulfur atom.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a photoelectric conversion element material, an organic thin film, a photoelectric conversion element, and an imaging element, which are made of a compound having a dicarbazole ring. [Background technology]

[0002] Photoelectric conversion elements are widely used in solar cells, optical sensors, etc., and among them, image sensors, which are imaging elements, are used not only in television cameras and cameras installed in smartphones, but also in image input devices for driving assistance systems, so their applications and market are expanding.

[0003] Until now, imaging elements have been made of inorganic materials such as Si films and Se films, and the two main imaging methods used were a three-plate type that uses a prism to separate the colors of incident light, and a single-plate type that uses a color filter. However, although the three-plate type has a high light utilization rate, it is difficult to make it compact because it uses a prism, while the single-plate type is relatively easy to make compact, but instead uses a color filter, which results in poor resolution and light utilization (Non-Patent Document 1).

[0004] Compared to inorganic materials, organic materials have a higher selectivity for absorption wavelengths, so by combining materials tailored to each wavelength, it is possible to build a small image sensor that can efficiently use light for each of the three primary colors without using a prism. In addition, photoelectric conversion devices using organic materials may have added value, such as flexibility and the ability to increase the area by using a coating process when creating the device (Non-Patent Document 2).

[0005] For these reasons, photoelectric conversion elements using organic materials are expected to be used in next-generation imaging elements, and several reports have been published. For example, there are examples using quinacridone and quinazoline derivatives in photoelectric conversion elements (Patent Document 1), benzothienobenzothiophene derivatives in photoelectric conversion elements (Patent Document 2), and indolocarbazole in photoelectric conversion elements (Patent Document 3). Generally, organic imaging elements are designed to achieve high contrast and low power consumption, and it is believed that performance can be improved by reducing dark current. To reduce dark current, a technique of inserting a hole-blocking layer or electron-blocking layer between the photoelectric conversion unit and the electrode unit is sometimes used.

[0006] Hole-blocking layers and electron-blocking layers are commonly used in the field of organic electronics, and are disposed at the interface between an electrode or conductive film and other films in the constituent films of a device, respectively, to control the reverse movement of holes or electrons while allowing the necessary charges to move quickly. Patent Document 4 proposes that compounds with a highest occupied molecular orbital (HOMO) level of -4.7 to -5.8 eV as electron-blocking materials are effective in efficiently transferring charges to electrodes.

[0007] High sensitivity is required for the photoelectric conversion layer, and there are several methods for achieving this. Since photoelectric conversion occurs at the interface between p-type and n-type semiconductors, the active layer has a bulk heterostructure to increase the interface area. In order to efficiently separate holes and electrons from excitons generated by light absorption, a compound with strong acceptor properties is used in the active layer.

[0008] In devices with electron blocking layers, if the active layer has a bulk heterostructure, an interface will be formed between the electron blocking layer and the n-type semiconductor. When a compound with strong acceptor properties is used as the n-type semiconductor, unless a compound with an appropriate energy level is used as the electron blocking layer, electrons will transfer from the highest occupied molecular orbital (HOMO) of the organic semiconductor material to the lowest unoccupied molecular orbital (LUMO) of the strong acceptor compound (fullerene derivative in Patent Document 5), resulting in poor dark current characteristics. In the HOMO-level electron blocking layer proposed in Patent Document 4, if a material with strong acceptor properties and a deep LUMO level, such as a fullerene derivative, is used in the active layer, the energy levels of the HOMO level of the electron blocking layer and the LUMO level of the n-type semiconductor in the active layer will be close, resulting in electron transfer from the n-type semiconductor material in the active layer to the electron blocking layer, resulting in poor dark current characteristics.

[0009] In order to prevent the above electron transfer, it is necessary to deepen the HOMO level of the material used in the electron blocking layer.

[0010] Another characteristic required for materials used in blocking layers is thermal stability. Imaging devices, in particular, require higher thermal stability than organic electroluminescence (EL) and other organic electronic devices, due to considerations of application to manufacturing processes involving heating, such as color filter installation, protective film installation, and device soldering, as well as improved shelf life. Patent Document 4 reports that the thermal stability of devices can be improved by using an electron-blocking material with a glass transition temperature of 140°C or higher. However, the characteristics were insufficient. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] Japanese Patent No. 4945146 [Patent Document 2] Japanese Patent Application Publication No. 2018-170487 [Patent Document 3] Japanese Patent Application Publication No. 2018-085427 [Patent Document 4] Japanese Patent Application Publication No. 2011-187937 [Patent Document 5] Japanese Patent No. 5624987 [Patent Document 6] Japanese Patent No. 6389459 [Non-patent literature]

[0012] [Non-Patent Document 1] Journal of the Institute of Image Information and Communications Technology, 60,3,291 (2006) [Non-patent document 2] Adv. Mater.28,4766(2016) Summary of the Invention [Problem to be solved by the invention]

[0013] The present invention has been made in view of the above-mentioned current situation, and aims to provide an organic thin film for use in a photoelectric conversion element by utilizing a material for a photoelectric conversion element having a deep HOMO level and excellent heat resistance, thereby providing various photoelectric conversion elements, particularly image sensors, to which the organic thin film is applied, and optical sensors using the same. [Means for solving the problem]

[0014] In order to solve the above problems, the present inventors have used a compound having a dicarbazole structure, which exhibits excellent heat resistance and electron blocking properties, as a material for a photoelectric conversion element, and have thereby completed the present invention.

[0015] That is, the present invention relates to the following.

[0016] A material for a photoelectric conversion element, comprising a compound having a dicarbazole ring represented by the following general formula (1):

[0017] [ka] (In the formula, X represents an oxygen atom or a sulfur atom; L1 and L2 may be the same or different and represent a single bond, a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aromatic heterocyclic group, or a divalent group of a substituted or unsubstituted fused polycyclic aromatic group; Ar1 and Ar2 may be the same or different and represent an optionally substituted linear or branched alkyl group of 1 to 6 carbon atoms, an optionally substituted cycloalkyl group of 5 to 10 carbon atoms, an optionally substituted linear or branched alkenyl group of 2 to 6 carbon atoms, an optionally substituted linear or branched alkyloxy group of 1 to 6 carbon atoms, an optionally substituted cycloalkyloxy group of 5 to 10 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aromatic heterocyclic group, a substituted or unsubstituted fused polycyclic aromatic group, or a substituted or unsubstituted aryloxy group; R1 to R12 may be the same or different and represent a hydrogen atom, a deuterium atom, a fluorine atom, a chlorine atom, a cyano group, a nitro group, an optionally substituted linear or branched alkyl group of 1 to 6 carbon atoms, an optionally substituted cycloalkyl group of 5 to 10 carbon atoms, an optionally substituted linear or branched alkenyl group of 2 to 6 carbon atoms, an optionally substituted linear or branched alkyloxy group of 1 to 6 carbon atoms, an optionally substituted cycloalkyloxy group of 5 to 10 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aromatic heterocyclic group, a substituted or unsubstituted fused polycyclic aromatic group, or a substituted or unsubstituted aryloxy group, and adjacent groups may be bonded to each other via a single bond, a substituted or unsubstituted methylene group, an oxygen atom, or a sulfur atom to form a ring. [Effects of the Invention]

[0018] The photoelectric conversion element material having a deep HOMO level of the present invention can be applied to various photoelectric conversion elements as an organic thin film containing the material, thereby providing a photoelectric conversion element, particularly an image sensor, with excellent dark current characteristics, and an optical sensor using the same. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 1 shows an example of the configuration of a photoelectric conversion element of the present invention. [Figure 2] FIG. 2 shows the structures of compounds (1-1) to (1-19) as examples of the compound represented by general formula (1). [Figure 3] FIG. 3 shows the structures of compounds (1-20) to (1-38) as examples of the compound represented by general formula (1). [Figure 4] FIG. 4 shows the structures of compounds (1-39) to (1-59) as examples of the compound represented by general formula (1). [Figure 5] FIG. 5 shows the structures of compounds (1-60) to (1-79) as examples of the compound represented by general formula (1). DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, embodiments of the present invention will be described in detail.

[0021] In this specification, the term "to" is used to indicate a range. For example, "5 to 10" means "5 or more and 10 or less," and indicates a range that includes the numerical values ​​written before and after "to."

[0022] <<Photoelectric conversion element materials>> The material for a photoelectric conversion element is made of a compound having a dicarbazole structure represented by the following general formula (1).

[0023] [ka] (In the formula, X represents an oxygen atom or a sulfur atom; L1 and L2 may be the same or different and represent a single bond, a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aromatic heterocyclic group, or a divalent group of a substituted or unsubstituted fused polycyclic aromatic group; Ar1 and Ar2 may be the same or different and represent an optionally substituted linear or branched alkyl group of 1 to 6 carbon atoms, an optionally substituted cycloalkyl group of 5 to 10 carbon atoms, an optionally substituted linear or branched alkenyl group of 2 to 6 carbon atoms, an optionally substituted linear or branched alkyloxy group of 1 to 6 carbon atoms, an optionally substituted cycloalkyloxy group of 5 to 10 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aromatic heterocyclic group, a substituted or unsubstituted fused polycyclic aromatic group, or a substituted or unsubstituted aryloxy group; R1 to R12 may be the same or different and represent a hydrogen atom, a deuterium atom, a fluorine atom, a chlorine atom, a cyano group, a nitro group, an optionally substituted linear or branched alkyl group of 1 to 6 carbon atoms, an optionally substituted cycloalkyl group of 5 to 10 carbon atoms, an optionally substituted linear or branched alkenyl group of 2 to 6 carbon atoms, an optionally substituted linear or branched alkyloxy group of 1 to 6 carbon atoms, an optionally substituted cycloalkyloxy group of 5 to 10 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aromatic heterocyclic group, a substituted or unsubstituted fused polycyclic aromatic group, or a substituted or unsubstituted aryloxy group, and adjacent groups may be bonded to each other via a single bond, a substituted or unsubstituted methylene group, an oxygen atom, or a sulfur atom to form a ring.

[0024] The divalent group of the "aromatic hydrocarbon group," "aromatic heterocyclic group," or "fused polycyclic aromatic group" in the "substituted or unsubstituted aromatic hydrocarbon group," "substituted or unsubstituted aromatic heterocyclic group," or "substituted or unsubstituted fused polycyclic aromatic group" in the general formula (1) is not particularly limited, and examples thereof include a phenylene group, a biphenylene group, a terphenylene group, a naphthylene group, an anthracenylene group, a thienylene group, a furanylene group, a phenanthrenylene group, a pyridylene group, a benzofuranylene group, a benzothienylene group, etc. Furthermore, it can also be selected from an arylene group having 6 to 30 carbon atoms and a heteroarylene group having 2 to 30 carbon atoms.

[0025] The "aromatic hydrocarbon group", "aromatic heterocyclic group" or "fused polycyclic aromatic group" in the "substituted or unsubstituted aromatic hydrocarbon group", "substituted or unsubstituted aromatic heterocyclic group" or "substituted or unsubstituted fused polycyclic aromatic group" in the general formula (1) is not particularly limited, and specific examples thereof include a phenyl group, a biphenylyl group, a terphenylyl group, a naphthyl group, an anthracenyl group, a phenanthrenyl group, a fluorenyl group, a spirobifluorenyl group, an indenyl group, a pyrenyl group, a perylenyl group, a fluoren ... Examples include an olanthenyl group, a triphenylenyl group, a pyridyl group, a pyrimidinyl group, a triazinyl group, a furyl group, a pyrrolyl group, a thienyl group, a quinolyl group, an isoquinolyl group, a benzofuranyl group, a benzothienyl group, an indolyl group, a carbazolyl group, a benzoxazolyl group, a benzothiazolyl group, a quinoxalinyl group, a benzimidazolyl group, a pyrazolyl group, a dibenzofuranyl group, a dibenzothienyl group, a naphthyridinyl group, a phenanthrolinyl group, an acridinyl group, and a carbolinyl group. Furthermore, the alkyl group may be selected from an aryl group having 6 to 30 carbon atoms and a heteroaryl group having 2 to 30 carbon atoms.

[0026] In the "optionally substituted linear or branched alkyl group of 1 to 6 carbon atoms," "optionally substituted cycloalkyl group of 5 to 10 carbon atoms," or "optionally substituted linear or branched alkenyl group of 2 to 6 carbon atoms" in general formula (1), the "linear or branched alkyl group of 1 to 6 carbon atoms," "cycloalkyl group of 5 to 10 carbon atoms," or "linear or branched alkenyl group of 2 to 6 carbon atoms" is not particularly limited, and specific examples thereof include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, neopentyl, n-hexyl, cyclopentyl, cyclohexyl, 1-adamantyl, 2-adamantyl, vinyl, allyl, isopropenyl, and 2-butenyl.

[0027] The "linear or branched alkyloxy group having 1 to 6 carbon atoms" or the "cycloalkyloxy group having 5 to 10 carbon atoms" in the "linear or branched alkyloxy group having 1 to 6 carbon atoms which may have a substituent" or the "cycloalkyloxy group having 5 to 10 carbon atoms which may have a substituent" in the general formula (1) is not particularly limited, and specific examples thereof include a methyloxy group, an ethyloxy group, an n-propyloxy group, an isopropyloxy group, an n-butyloxy group, a tert-butyloxy group, an n-pentyloxy group, an n-hexyloxy group, a cyclopentyloxy group, a cyclohexyloxy group, a cycloheptyloxy group, a cyclooctyloxy group, a 1-adamantyloxy group, and a 2-adamantyloxy group.

[0028] The "aryloxy group" in the "substituted or unsubstituted aryloxy group" in general formula (1) is not particularly limited, and specific examples thereof include aryloxy groups having 6 to 30 carbon atoms, such as a phenyloxy group, a biphenylyloxy group, a terphenylyloxy group, a naphthyloxy group, an anthracenyloxy group, and a phenanthrenyloxy group.

[0029] The "substituents" in the "substituted aromatic hydrocarbon group," "substituted aromatic heterocyclic group," "substituted fused polycyclic aromatic group," "substituted methylene group," "optionally substituted linear or branched alkyl group of 1 to 6 carbon atoms," "optionally substituted cycloalkyl group of 5 to 10 carbon atoms," "optionally substituted linear or branched alkenyl group of 2 to 6 carbon atoms," "optionally substituted linear or branched alkyloxy group of 1 to 6 carbon atoms," or "optionally substituted cycloalkyloxy group of 5 to 10 carbon atoms" in general formula (1) are not particularly limited, and specifically include, for example, deuterium atoms, cyano groups, nitro groups; halogen atoms such as fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms; silyl groups such as trimethylsilyl groups and triphenylsilyl groups; linear or branched alkyl groups of 1 to 6 carbon atoms such as methyl groups, ethyl groups, and propyl groups; carbon atoms such as methyloxy groups, ethyloxy groups, and propyloxy groups. linear or branched alkyloxy groups having 1 to 6 atoms; alkenyl groups such as vinyl and allyl; aryloxy groups such as phenyloxy and tolyloxy; arylalkyloxy groups such as benzyloxy and phenethyloxy; aromatic groups such as phenyl, biphenylyl, terphenylyl, naphthyl, anthracenyl, phenanthrenyl, fluorenyl, spirobifluorenyl, indenyl, pyrenyl, perylenyl, fluoranthenyl, and triphenylenyl. Examples of the substituent include an aromatic hydrocarbon group or a condensed polycyclic aromatic group; and aromatic heterocyclic groups such as a pyridyl group, a thienyl group, a furyl group, a pyrrolyl group, a quinolyl group, an isoquinolyl group, a benzofuranyl group, a benzothienyl group, an indolyl group, a carbazolyl group, a benzoxazolyl group, a benzothiazolyl group, a quinoxalinyl group, a benzimidazolyl group, a pyrazolyl group, a dibenzofuranyl group, a dibenzothienyl group, and a carbolinyl group, and these substituents may be further substituted with the substituents exemplified above.

[0030] In general formula (1), preferably, X is an oxygen atom, and Ar1 and Ar2 may be the same or different and are a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aromatic heterocyclic group, or a substituted or unsubstituted fused polycyclic aromatic group.

[0031] In the general formula (1), Ar1 and Ar2 may have a structure selected from the group consisting of the following general formulae (2a) to (2u).

[0032] [ka] (In the formula, Ar3 has the same definition as Ar1 and Ar2 in general formula (1), R13 to R15 may be the same as or different from each other and have the same definition as R1 to R12 in general formula (1), The dashed line indicates the binding site. a represents an integer of 0 to 5; b represents an integer of 0 to 4, c represents an integer of 0 to 3; d represents an integer of 0 to 2.

[0033] In the general formula (1), L1 and L2 may be the same or different and each represent a single bond, The structure may be selected from the group consisting of a phenylene group and a biphenylene group.

[0034] Among the compounds having a dicarbazole ring represented by general formula (1), specific examples of preferred compounds are shown in FIGS. 2 to 5, but the compounds are not limited to these.

[0035] From the viewpoint of suppressing dark current, the material for a photoelectric conversion element preferably has a HOMO level of −5.8 eV or less.

[0036] The above-mentioned compound having a dicarbazole skeleton can be synthesized according to a method known per se (for example, Patent Document 6).

[0037] The compound represented by general formula (1) can be purified by column chromatography, adsorption purification using silica gel, activated carbon, activated clay, or the like, or recrystallization or crystallization using a solvent. The compound can be identified by NMR spectroscopy. It is preferable to measure the glass transition temperature and HOMO level as physical property values. The glass transition temperature is an index of the stability of the thin film state, and the HOMO level is an index of the hole transport property.

[0038] The glass transition temperature can be determined using a powder with a high-sensitivity differential scanning calorimeter (DSC3100SA, manufactured by Bruker AXS).

[0039] The HOMO level can be determined by forming a 100 nm thin film on an ITO substrate and using an ionization potential measuring device (PYS-202, manufactured by Sumitomo Heavy Industries, Ltd.).

[0040] <<Organic thin film>> The photoelectric conversion element material can be used to form an organic thin film by known methods such as vapor deposition, spin coating, and ink jet printing. The photoelectric conversion element material may be used alone to form a film, or multiple types of materials may be mixed to form a film. Furthermore, the material may be mixed with other compounds to form a film, provided that the effects of the present invention are not impaired.

[0041] An organic thin film containing a material for a photoelectric conversion element can be used as a blocking layer or a photoelectric conversion layer, and is suitable for use in a photoelectric conversion element, particularly an imaging element.

[0042] <<Photoelectric conversion element>> The photoelectric conversion element may be configured, for example, to have, in order, a first electrode (anode), a blocking layer, a photoelectric conversion layer, and a second electrode (cathode). The blocking layer is a hole-blocking layer or an electron-blocking layer, and is preferably an electron-blocking layer. It is particularly preferred that the electron-blocking layer is an organic thin film containing a material for photoelectric conversion elements. In such a multilayer structure, additional layers can be added, and for example, a configuration can be made in which, in order, a first electrode, an electron-blocking layer, a photoelectric conversion layer, a hole-blocking layer, and a second electrode are included.

[0043] <<Photoelectric conversion layer>> The photoelectric conversion layer may be made of either an organic or inorganic material, as long as it can generate signal charges according to the amount of light received. When the photoelectric conversion layer is made of an organic material, the organic semiconductor film may be a single layer or multiple layers. When the photoelectric conversion layer is made of a single layer, a p-type organic semiconductor film, an n-type organic semiconductor film, or a mixed film of p-type organic semiconductor and n-type organic semiconductor (bulk heterostructure) is used. When the photoelectric conversion layer is made of multiple layers, the structure is a stack of two or more of a p-type organic semiconductor film, an n-type organic semiconductor film, or a mixed film of p-type organic semiconductor and n-type organic semiconductor, and a buffer layer can be inserted between the layers.

[0044] The p-type semiconductor used in the photoelectric conversion layer is a donor organic semiconductor, which is mainly represented by a hole-transporting organic compound and is a compound that has the property of readily donating electrons. The p-type semiconductor is not particularly limited, and examples thereof include thienoacene-based materials typified by naphthalene derivatives, anthracene derivatives, phenanthrene derivatives, pyrene derivatives, perylene derivatives, tetracene derivatives, pentacene derivatives, quinacridone derivatives, chrysene derivatives, fluoranthene derivatives, phthalocyanine derivatives, subphthalocyanine derivatives, metal complexes having a heterocyclic compound as a ligand, benzothiophene derivatives, dinaphthothienothiophene derivatives, dianthracenothienothiophene derivatives, benzobisbenzothiophene derivatives, thienobisbenzothiophene derivatives, dibenzothienobisbenzothiophene derivatives, dithienobenzodithiophene derivatives, dibenzothienodithiophene derivatives, benzodithiophene derivatives, naphthodithiophene derivatives, anthracenodithiophene derivatives, tetracenodithiophene derivatives, and pentacenodithiophene derivatives; amine-based derivatives such as triarylamine compounds and carbazole compounds; and indenocarbazole derivatives.

[0045] The n-type organic semiconductor used in the photoelectric conversion layer is an acceptor organic semiconductor, which is mainly represented by an electron-transporting organic compound and refers to an organic compound that has the property of easily accepting electrons. More specifically, when two organic compounds are used in contact with each other, the organic compound with the larger electron affinity is the one that is the acceptor. Therefore, any organic compound that has electron-accepting properties can be used as the acceptor organic compound. For example, fused aromatic carbocyclic compounds (naphthalene, anthracene, fullerene, phenanthrene, tetracene, pyrene, perylene, fluoranthene, or derivatives thereof), 5- to 7-membered heterocyclic compounds containing nitrogen atoms, oxygen atoms, or sulfur atoms (e.g., pyridine, pyrazine, pyrimidine, pyridazine, triazine, quinoline, quinoxaline, quinazoline, phthalazine, cinnoline, isoquinoline, pteridine, acridine, phenazine, phenanthroline, tetrazole, pyrazole, imidazole, thiazole, Examples of the acceptor organic semiconductor include metal complexes having, as a ligand, oxazole, indazole, benzimidazole, benzotriazole, benzoxazole, benzothiazole, carbazole, purine, triazolopyridazine, triazolopyrimidine, tetrazaindene, oxadiazole, imidazopyridine, pyrazine, pyrrolopyridine, thiadiazolopyridine, dibenzazepine, tribenzazepine, etc.), polyarylene compounds, fluorene compounds, cyclopentadiene compounds, silyl compounds, and nitrogen-containing heterocyclic compounds. However, the acceptor organic semiconductor is not limited to these, and any organic compound having a larger electron affinity than the organic compound used as the donor organic compound may be used as the acceptor organic semiconductor, as described above.

[0046] The thickness of the photoelectric conversion layer is preferably 100 to 1000 nm, and more preferably 100 to 500 nm.

[0047] <<Conductive thin film>> The conductive thin film is an anode and a cathode, and is made of a conductive material. It may be a transparent conductive thin film. The anode and the cathode may be made of any conductive material commonly used as an electrode, including metals, metal oxides, metal nitrides, metal borides, organic conductive compounds, and mixtures thereof. Specific examples include conductive metal oxides such as tin oxide, zinc oxide, indium oxide, indium tin oxide (ITO), indium zinc oxide (IZO), indium tungsten oxide (IWO), molybdenum oxide (MoO), and titanium oxide; metal nitrides such as titanium oxynitride (TiNxOx) and titanium nitride (TiN); metals such as gold (Au), platinum (Pt), silver (Ag), chromium (Cr), nickel (Ni), and aluminum (Al); mixtures or laminates of these metals and conductive metal oxides; organic conductive compounds such as polyaniline, polythiophene, and polypyrrole; and laminates of these compounds with ITO.

[0048] <<Hole-blocking layer>> A hole-blocking layer may be inserted between the second electrode (cathode) and the photoelectric conversion layer, and the material used therefor is preferably a material with electron transport ability. For example, organic molecules and organometallic complexes containing nitrogen-containing heterocycles such as pyridine, quinoline, acridine, indole, imidazole, benzimidazole, and phenanthroline are preferred, as are materials with low absorption in the visible light region. Furthermore, when forming a thin film of about 5 to 30 nm, fullerenes and fullerene derivatives that absorb in the visible light region can also be used.

[0049] <<Image sensor>> The imaging element is configured to include the photoelectric conversion element. [Example]

[0050] Hereinafter, the embodiment will be described in detail with reference to examples, but the present invention is not limited to the following examples. [Example]

[0051] Synthesis of 5,7-dihydro-5,7-bis(9,9-dimethylfluoren-2-yl)-furo[2,3-a:5,4-a']dicarbazole; (Synthesis of Compound 1-3)

[0052] A nitrogen-purged reaction vessel was charged with 10.4 g of N,N,N',N'-tetramethylethylenediamine and 40 ml of THF, cooled, and a hexane solution of n-butyllithium (1.6 mol / L) was added dropwise while maintaining the solution temperature below 0°C. The mixture was stirred at 0°C for 30 minutes, followed by another 30 minutes at room temperature. Next, 25 ml of THF and 5.0 g of dibenzofuran were added, heated, and stirred at 60°C for 2 hours. Next, while cooling to below -60°C, 16.8 g of 1,2-diiodoethane was added and stirred at room temperature overnight. Water and dichloromethane were added, and the organic layer was separated and collected. The organic layer was dehydrated over anhydrous magnesium sulfate and concentrated under reduced pressure to obtain a crude product. Heptane was added to the crude product, stirred, and the precipitate was collected by filtration to obtain 2.7 g of 4,6-diiododibenzofuran as a pale yellow powder (22% yield).

[0053] The 4,6-diiododibenzofuran (2.7 g), 2.2 g of 2-bromoaniline, 1.5 g of sodium tert-butoxide, and 27 ml of toluene obtained above were added to a nitrogen-purged reaction vessel, and nitrogen gas was bubbled through for 1 hour. Then, 0.2 g of tris(dibenzylideneacetone)dipalladium(0) and 0.3 g of diphenylphosphinoferrocene were added to the reaction vessel, heated, and stirred at 100°C for 4 hours. After cooling to room temperature, insoluble matter was removed by filtration, and the filtrate was concentrated under reduced pressure to obtain a crude product. This crude product was purified by column chromatography (carrier: silica gel, eluent: toluene / n-hexane) and purified by N 4 ,N 6 2.4 g (73% yield) of a light brown powder of 4,6-bis(2-bromophenyl)-dibenzofuran-4,6-diamine was obtained.

[0054] The reaction vessel was purged with nitrogen and the N 4 ,N 6A mixture of 2.4 g of a light brown powder of 5,7-dihydro-bis(2-bromophenyl)-dibenzofuran-4,6-diamine, 1.9 g of potassium acetate, 12 ml of DMF, and 2 ml of water was added, and nitrogen gas was bubbled through the mixture for 1 hour. 0.2 g of tetrakis(triphenylphosphine)palladium was then added, and the mixture was heated and stirred at 72°C for 12 hours. After cooling to room temperature, 30 ml of water and 30 ml of toluene were added. The solid was collected by filtration, yielding 0.5 g (30% yield) of a light brown powder of 5,7-dihydro-furo[2,3-a:5,4-a']dicarbazole.

[0055] The resulting 5,7-dihydro-furo[2,3-a:5,4-a']dicarbazole (7.5 g), 2-iodo-9,9-dimethylfluorene (17.3 g), copper iodide (0.2 g), tripotassium phosphate (13.8 g), 1,2-cyclohexanediamine (7.4 g), and 1,4-dioxane (60 ml) were added to a nitrogen-purged reaction vessel, heated, and stirred at 95°C for 45 hours. After cooling to room temperature, 60 ml of water and 60 ml of toluene were added, followed by extraction with toluene to collect the organic layer. The organic layer was dehydrated over anhydrous magnesium sulfate and then concentrated under reduced pressure to obtain a crude product. This crude product was purified by column chromatography (carrier: silica gel, eluent: toluene / n-heptane) to obtain 13.8 g (87% yield) of a white powder of 5,7-dihydro-5,7-bis(9,9-dimethylfluoren-2-yl)-furo[2,3-a:5,4-a']dicarbazole (compound 1-3).

[0056] [ka]

[0057] The structure of the obtained white powder was identified using NMR.

[0058] 1 The following 26 hydrogen signals were detected by H NMR (CDCl3). δ(ppm)=8.21(4H),8.03(2H),7.30-7.50(16H),7.18(4H) [Example]

[0059] Synthesis of 5,7-dihydro-5,7-bis{4-(dibenzofuran-4-yl)phenyl}-furo[2,3-a:5,4-a']dicarbazole; (Synthesis of Compound 1-4)

[0060] A nitrogen-purged reaction vessel was charged with 6.0 g of 5,7-dihydrofuro[2,3-a:5,4-a']dicarbazole (synthesized in Example 1), 12.3 g of 4-(4-bromophenyl)dibenzofuran, 5.0 g of sodium tert-butoxide, and 60 ml of toluene, and nitrogen gas was bubbled through for 1 hour. Then, 0.6 g of tris(dibenzylideneacetone)dipalladium(0) and 0.8 g of a 50% (w / v) toluene solution of tri-tert-butylphosphine were added to the reaction vessel, heated, and stirred at 95°C for 18 hours. After cooling to room temperature and adding water, the organic layer was extracted with toluene to obtain a crude product. The organic layer was dehydrated over anhydrous magnesium sulfate and then concentrated under reduced pressure to obtain a crude product. This crude product was purified by column chromatography (carrier: silica gel, eluent: toluene / n-hexane) to obtain 2.7 g (18% yield) of white powder of 5,7-dihydro-5,7-bis{4-(dibenzofuran-4-yl)phenyl}-furo[2,3-a:5,4-a']dicarbazole (compound 1-4).

[0061] [ka]

[0062] The structure of the obtained white powder was identified using NMR.

[0063] 1 The following 34 hydrogen signals were detected by H NMR (CDCl3). δ(ppm)=8.23(4H),8.04(2H),7.77-7.90(6H),7.32-7.57(20H),7.08(2H) [Example]

[0064] Synthesis of 5,7-dihydro-5,7-bis(biphenyl-4-yl)-furo[2,3-a:5,4-a']dicarbazole; (Synthesis of Compound 1-5)

[0065] A nitrogen-purged reaction vessel was charged with 7.4 g of 5,7-dihydro-furo[2,3-a:5,4-a']dicarbazole (synthesized in Example 1), 13.2 g of 4-iodobiphenyl, 6.2 g of sodium tert-butoxide, and 70 ml of toluene, and nitrogen gas was bubbled through for 1 hour. Then, 0.8 g of tris(dibenzylideneacetone)dipalladium(0) and 1.0 g of a 50% (w / v) toluene solution of tri-tert-butylphosphine were added to the reaction vessel, heated, and stirred at 95°C for 29 hours. After cooling to room temperature, water was added, and the organic layer was extracted with toluene. The organic layer was dehydrated over anhydrous magnesium sulfate and then concentrated under reduced pressure to obtain a crude product. This crude product was purified by column chromatography (carrier: silica gel, eluent: toluene / n-hexane) to obtain 6.0 g (43% yield) of white powder of 5,7-dihydro-5,7-bis(biphenyl-4-yl)-furo[2,3-a:5,4-a']dicarbazole (compound 1-5).

[0066] [ka]

[0067] The structure of the obtained white powder was identified using NMR.

[0068] 1 The following 30 hydrogen signals were detected by H NMR (CDCl3). δ(ppm)=8.18-8.22(4H),8.01(2H),7.30-7.50(24H) [Example]

[0069] Synthesis of 5,7-dihydro-5-{4-(9-phenylcarbazol-3-yl)phenyl}-7-phenylfuro[2,3-a:5,4-a']dicarbazole; (Synthesis of Compound 1-24)

[0070] A nitrogen-purged reaction vessel was charged with 7.0 g of 5,7-dihydrofuro[2,3-a:5,4-a']dicarbazole (synthesized in Example 1), 10.5 g of 3-(4-bromophenyl)-9-phenylcarbazole, 9.9 g of cesium carbonate, and 70 ml of xylene, and nitrogen gas was bubbled through for 1 hour. Then, 0.9 g of tris(dibenzylideneacetone)dipalladium(0) and 0.8 g of a 50% (w / v) toluene solution of tri-tert-butylphosphine were added to the reaction vessel, heated, and stirred at 110°C for 42 hours. After cooling to room temperature, 70 ml of water was added. The precipitated solid was collected by filtration and washed with 70 ml of a methanol / water (5 / 1, v / v) mixed solvent. Then, 200 ml of 1,2-dichlorobenzene was added and dissolved by heating. The insoluble matter was removed by filtration, and the mixture was allowed to cool. 100 ml of heptane was then added, and the precipitated crude product was collected by filtration to obtain 8.2 g (yield 61%) of 5,7-dihydro-5-{4-(9-phenylcarbazol-3-yl)phenyl}-furo[2,3-a:5,4-a']dicarbazole as a gray powder.

[0071] In a nitrogen-purged reaction vessel, 8.2 g of the 5,7-dihydro-5-{4-(9-phenylcarbazol-3-yl)phenyl}-furo[2,3-a:5,4-a']dicarbazole obtained above, 3.8 g of iodobenzene, 0.1 g of copper iodide, 3.9 g of tripotassium phosphate, 2.1 g of 1,2-cyclohexanediamine, and 70 ml of 1,4-dioxane were added and heated to 95°C with stirring for 20 hours. After cooling to room temperature, 70 ml of water and 70 ml of toluene were added, and the organic layer was extracted with toluene to obtain the crude product. The organic layer was dehydrated over anhydrous magnesium sulfate and then concentrated under reduced pressure to obtain the crude product. This crude product was purified by column chromatography (carrier: silica gel, eluent: toluene / n-heptane) to obtain 7.0 g (77% yield) of a white powder of 5,7-dihydro-5-{4-(9-phenylcarbazol-3-yl)phenyl}-7-phenyl-furo[2,3-a:5,4-a']dicarbazole (compound 1-24).

[0072] [ka]

[0073] The structure of the obtained white powder was identified using NMR.

[0074] 1 The following 33 hydrogen signals were detected by H NMR (CDCl3). δ(ppm)=8.58(1H),8.34(1H),8.18-8.25(4H),8.00(2H),7.90(1H),7.62-7.77(7H),7.49-7.60(6H),7.30-7.50(8H),7.09(2H),6.88(1H) [Example]

[0075] Synthesis of 5,7-dihydro-5-[4-{(biphenyl-4-yl)-phenylamino}biphenyl-4-yl]-7-phenyl-furo[2,3-a:5,4-a']dicarbazole: (Synthesis of Compounds 1-25)

[0076] A nitrogen-purged reaction vessel was charged with 7.0 g of 5,7-dihydro-furo[2,3-a:5,4-a']dicarbazole (synthesized in Example 1), 15.5 g of N-(biphenyl-4-yl)-N-phenyl-(4-bromobiphenyl-4-yl)amine, 19.8 g of cesium carbonate, and 70 ml of xylene, and nitrogen gas was bubbled through for 1 hour. Then, 0.9 g of tris(dibenzylideneacetone)dipalladium(0) and 0.8 g of a 50% (w / v) toluene solution of tri-tert-butylphosphine were added to the reaction vessel, heated, and stirred at 110°C for 15 hours. The mixture was cooled to room temperature, and 70 ml of water was added. The precipitated solid was collected by filtration and washed with 70 ml of a mixed solvent of methanol / water (5 / 1, v / v). Then, 200 ml of 1,2-dichlorobenzene was added and dissolved by heating. The insoluble matter was removed by filtration, and the mixture was allowed to cool. Then, 100 ml of methanol was added to the mixture, and the precipitated crude product was collected by filtration to obtain 7.8 g (yield 52%) of 5,7-dihydro-5-[4-{(biphenyl-4-yl)-phenylamino}biphenyl-4-yl]-furo[2,3-a:5,4-a']dicarbazole as a gray powder.

[0077] A nitrogen-purged reaction vessel was charged with 7.6 g of the 5,7-dihydro-5-[4-{(biphenyl-4-yl)-phenylamino}biphenyl-4-yl]-furo[2,3-a:5,4-a']dicarbazole obtained above, 3.2 g of iodobenzene, 0.1 g of copper iodide, 3.4 g of tripotassium phosphate, 1.8 g of 1,2-cyclohexanediamine, and 60 ml of 1,4-dioxane, and the mixture was heated and stirred at 95°C for 22 hours. After cooling to room temperature, 70 ml of water and 70 ml of toluene were added, and the organic layer was extracted with toluene. The organic layer was dehydrated over anhydrous magnesium sulfate and then concentrated under reduced pressure to obtain a crude product. This crude product was purified by column chromatography (carrier: silica gel, eluent: toluene / heptane) to obtain 7.6 g (88% yield) of a white powder of 5,7-dihydro-5-[4-{(biphenyl-4-yl)-phenylamino}biphenyl-4-yl]-7-phenyl-furo[2,3-a:5,4-a']dicarbazole (compound 1-25).

[0078] [ka]

[0079] The structure of the obtained white powder was identified using NMR.

[0080] 1 The following 39 hydrogen signals were detected by H NMR (CDCl3). δ(ppm)=8.15-8.25(4H),7.99(2H),7.72(2H),7.54-7.70(6H),7.28-7.51(17H),7.18-7.24(6H),6.94(2H) [Example]

[0081] Synthesis of 5,7-dihydro-5-[4-{bis(biphenyl-4-yl)amino}phenyl]-7-phenyl-furo[2,3-a:5,4-a']dicarbazole; (Synthesis of Compound 1-47)

[0082] A nitrogen-purged reaction vessel was charged with 6.0 g of 5,7-dihydro-furo[2,3-a:5,4-a']dicarbazole (synthesized in Example 1), 8.3 g of (4-bromophenyl)-bis(biphenyl-4-yl)amine, 8.5 g of cesium carbonate, and 60 ml of xylene, and nitrogen gas was bubbled through for 1 hour. Then, 0.5 g of tris(dibenzylideneacetone)dipalladium(0) and 0.4 g of a 50% (w / v) toluene solution of tri-tert-butylphosphine were added to the reaction vessel, heated, and stirred at 110°C for 40 hours. The mixture was cooled to room temperature, and 60 ml of water was added. The precipitated solid was collected by filtration and washed with 60 ml of a mixed solvent of methanol / water (5 / 1, v / v). Then, 200 ml of 1,2-dichlorobenzene was added and dissolved by heating. The insoluble matter was removed by filtration, and the mixture was allowed to cool. Then, 100 ml of heptane was added, and the precipitated crude product was collected by filtration to obtain 8.5 g (yield 66%) of 5,7-dihydro-5-[4-{bis(biphenyl-4-yl)amino}phenyl]-furo[2,3-a:5,4-a']dicarbazole as a gray powder.

[0083] A nitrogen-purged reaction vessel was charged with 8.5 g of the 5,7-dihydro-5-[4-{bis(biphenyl-4-yl)amino}phenyl]-furo[2,3-a:5,4-a']dicarbazole obtained above, 3.5 g of iodobenzene, 0.1 g of copper iodide, 3.7 g of tripotassium phosphate, 2.0 g of 1,2-cyclohexanediamine, and 70 ml of 1,4-dioxane, and the mixture was heated and stirred at 95°C for 19 hours. After cooling to room temperature, 70 ml of water and 70 ml of heptane were added. The precipitated solid was collected by filtration and washed with 70 ml of a mixed solvent of methanol and water (5 / 1, v / v). Then, 100 ml of 1,2-dichlorobenzene was added and the mixture was heated to dissolve. Insoluble matter was removed by filtration, and the mixture was allowed to cool. 100 ml of heptane was added, and the precipitated crude product was collected by filtration. The crude product was refluxed with 100 ml of methanol to obtain 7.0 g (75% yield) of a light brown powder of 5,7-dihydro-5-[4-{bis(biphenyl-4-yl)amino}phenyl]-7-phenyl-furo[2,3-a:5,4-a']dicarbazole (compound 1-47).

[0084] [ka]

[0085] The structure of the resulting light brown powder was identified using NMR.

[0086] 1 The following 39 hydrogen signals were detected by H NMR (CDCl3). δ(ppm)=8.16-8.22(4H),7.99(2H),7.64-7.70(8H),7.30-7.58(21H),7.27(2H),7.03(2H) [Example]

[0087] Synthesis of 5,7-dihydro-5-[3-{2,6-diphenylpyrimidyl}phenyl]-7-phenyl-furo[2,3-a:5,4-a']dicarbazole; (Synthesis of Compound 1-56)

[0088] A nitrogen-purged reaction vessel was charged with 6.0 g of 5,7-dihydro-furo[2,3-a:5,4-a']dicarbazole (synthesized in Example 1), 6.7 g of 3-(2,6-diphenylpyrimidyl)-1-bromobenzene, 8.5 g of cesium carbonate, and 60 ml of xylene, and nitrogen gas was bubbled through for 1 hour. Then, 0.5 g of tris(dibenzylideneacetone)dipalladium(0) and 0.4 g of a 50% (w / v) toluene solution of tri-tert-butylphosphine were added to the reaction vessel, heated, and stirred at 110°C for 40 hours. The mixture was cooled to room temperature, and 60 ml of water was added. The precipitated solid was collected by filtration and washed with 60 ml of a mixed solvent of methanol / water (5 / 1, v / v). Then, 200 ml of 1,2-dichlorobenzene was added and dissolved by heating. The insoluble matter was removed by filtration, and the mixture was allowed to cool. Then, 100 ml of heptane was added, and the precipitated crude product was collected by filtration to obtain 4.5 g (yield 40%) of 5,7-dihydro-5-[3-{2,6-diphenylpyrimidyl}phenyl]-furo[2,3-a:5,4-a']dicarbazole as a gray powder.

[0089] A nitrogen-purged reaction vessel was charged with 4.3 g of the 5,7-dihydro-5-[3-{2,6-diphenylpyrimidyl}phenyl]-furo[2,3-a:5,4-a']dicarbazole obtained above, 3.5 g of iodobenzene, 0.1 g of copper iodide, 3.7 g of tripotassium phosphate, 2.0 g of 1,2-cyclohexanediamine, and 70 ml of 1,4-dioxane, and the mixture was heated and stirred at 95°C for 19 hours. After cooling to room temperature, 70 ml of water and 70 ml of heptane were added. The precipitated solid was collected by filtration and washed with 70 ml of a methanol / water (5 / 1, v / v) mixed solvent. 100 ml of 1,2-dichlorobenzene was added and the mixture was heated to dissolve. Insoluble matter was removed by filtration, and the mixture was allowed to cool. 100 ml of heptane was added, and the precipitated crude product was collected by filtration. The crude product was refluxed with 100 ml of methanol to obtain 3.8 g (75% yield) of white powder of 5,7-dihydro-5-[3-{2,6-diphenylpyrimidyl}phenyl]-7-phenyl-furo[2,3-a:5,4-a']dicarbazole (compound 1-56).

[0090] [ka]

[0091] The structure of the obtained white powder was identified using NMR.

[0092] 1 The following 32 hydrogen signals were detected by H NMR (CDCl3). δ(ppm)=8.69-8.68(2H),8.26-8.14(6H),8.05-8.02(4H),7.80(1H),7.71(1H),7.58- 7.56(2H),7.48-7.43(4H),7.37(2H),7.30-7.26(5H),7.20(2H),7.12(1H),7.02(2H) [Example]

[0093] The glass transition temperatures of the compounds of Examples 1, 2, and 4 to 7 were measured using a high-sensitivity differential scanning calorimeter (DSC3100SA, manufactured by Bruker AXS). High-glass transition temperature compounds EBL-1 (see Patent Document 4) and EBL-2 (see Patent Document 5), which have the following structures, were also measured using the same method. The results of the measured glass transition temperatures are summarized in Table 1.

[0094] [ka]

[0095] [ka]

[0096] [Table 1]

[0097] The compound of the embodiment has a high glass transition temperature of 140°C or higher, indicating that the thin film state is stable. Furthermore, the glass transition temperature of the compound of the present invention is higher than that of EBL-2, and by using it instead of EBL-2, it is possible to fabricate a device with better thermal stability. [Example]

[0098] <HOMO level measurement> Using the compounds of Examples 1 to 7 and the comparative compounds EBL-1 and EBL-2, vapor-deposited films with a thickness of 100 nm were prepared on ITO substrates, and the HOMO levels were measured using an ionization potential measurement device (Sumitomo Heavy Industries, Ltd., PYS-202). The results are summarized in Table 2.

[0099] [Table 2]

[0100] As shown in Table 2, the compounds of the examples have deeper energy levels, -5.80 to -6.01 eV, than the HOMO levels of the comparative compounds EBL-1 and EBL-2. Therefore, when used as an electron blocking layer, the energy difference between the HOMO level of the electron blocking layer and the LUMO level of the n-type semiconductor in the active layer becomes large, making it difficult for electrons to transfer from the n-type semiconductor material in the active layer to the electron blocking layer, thereby suppressing the transfer of charge at the interface with the n-type semiconductor. This improves dark current characteristics and makes it possible to fabricate devices with low dark current values.

[0101] The bright current and dark current of a photoelectric conversion element can be evaluated using an element configured as shown in Figure 1. Specifically, an ITO electrode is formed in advance as a transparent anode 2 on a glass substrate 1, and then an electron blocking layer 3, a photoelectric conversion layer 4, and a cathode 5 are vapor-deposited in this order on top of the ITO electrode. The bright current and dark current of the photoelectric conversion element can be evaluated using this fabricated element.

[0102] From the above results, it is clear that a photoelectric conversion element using an organic thin film containing the material for a photoelectric conversion element represented by general formula (1) has the HOMO level and high heat resistance required for the electron blocking layer of an organic photoelectric conversion element, and therefore it is possible to fabricate an element with a low dark current value.

[0103] Although the present invention has been described in detail with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention. This application is based on a Japanese patent application (Patent Application No. 2021-19520) filed on February 10, 2021, the entire contents of which are incorporated by reference. All references cited herein are incorporated in their entirety. [Industrial Applicability]

[0104] The material for photoelectric conversion elements of the present invention, which has high heat resistance and good charge mobility, can be applied to organic thin films and various photoelectric conversion elements, and therefore can provide photoelectric conversion elements, particularly image sensors, having good dark current characteristics and conversion efficiency, and optical sensors using the same. [Explanation of symbols]

[0105] 1. Glass substrate 2 transparent anode 3. Electron Blocking Layer 4 Photoelectric conversion layer 5 cathode

Claims

1. A photoelectric conversion element including an electron blocking layer, wherein the electron blocking layer includes a material for a photoelectric conversion element consisting of a compound having a dicarbazole ring represented by the following general formula (1). 【Chemistry 1】 (In the formula, X represents an oxygen atom or a sulfur atom; L1 and L2 may be the same or different and represent a single bond, a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aromatic heterocyclic group, or a divalent group of a substituted or unsubstituted fused polycyclic aromatic group; Ar1 and Ar2 may be the same or different and represent an optionally substituted linear or branched alkyl group of 1 to 6 carbon atoms, an optionally substituted cycloalkyl group of 5 to 10 carbon atoms, an optionally substituted linear or branched alkenyl group of 2 to 6 carbon atoms, an optionally substituted linear or branched alkyloxy group of 1 to 6 carbon atoms, an optionally substituted cycloalkyloxy group of 5 to 10 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aromatic heterocyclic group, a substituted or unsubstituted fused polycyclic aromatic group, or a substituted or unsubstituted aryloxy group; R1 to R12 may be the same or different and represent a hydrogen atom, a deuterium atom, a fluorine atom, a chlorine atom, a cyano group, a nitro group, an optionally substituted linear or branched alkyl group of 1 to 6 carbon atoms, an optionally substituted cycloalkyl group of 5 to 10 carbon atoms, an optionally substituted linear or branched alkenyl group of 2 to 6 carbon atoms, an optionally substituted linear or branched alkyloxy group of 1 to 6 carbon atoms, an optionally substituted cycloalkyloxy group of 5 to 10 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aromatic heterocyclic group, a substituted or unsubstituted fused polycyclic aromatic group, or a substituted or unsubstituted aryloxy group, and adjacent groups may be bonded to each other via a single bond, a substituted or unsubstituted methylene group, an oxygen atom, or a sulfur atom to form a ring.

2. A photoelectric conversion element including a photoelectric conversion layer, wherein the photoelectric conversion layer includes a material for a photoelectric conversion element consisting of a compound having a dicarbazole ring represented by the following general formula (1). 【Chemistry 2】 (In the formula, X represents an oxygen atom or a sulfur atom; L1 and L2 may be the same or different and represent a single bond, a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aromatic heterocyclic group, or a divalent group of a substituted or unsubstituted fused polycyclic aromatic group; Ar1 and Ar2 may be the same or different and represent an optionally substituted linear or branched alkyl group of 1 to 6 carbon atoms, an optionally substituted cycloalkyl group of 5 to 10 carbon atoms, an optionally substituted linear or branched alkenyl group of 2 to 6 carbon atoms, an optionally substituted linear or branched alkyloxy group of 1 to 6 carbon atoms, an optionally substituted cycloalkyloxy group of 5 to 10 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aromatic heterocyclic group, a substituted or unsubstituted fused polycyclic aromatic group, or a substituted or unsubstituted aryloxy group; R1 to R12 may be the same or different and represent a hydrogen atom, a deuterium atom, a fluorine atom, a chlorine atom, a cyano group, a nitro group, an optionally substituted linear or branched alkyl group of 1 to 6 carbon atoms, an optionally substituted cycloalkyl group of 5 to 10 carbon atoms, an optionally substituted linear or branched alkenyl group of 2 to 6 carbon atoms, an optionally substituted linear or branched alkyloxy group of 1 to 6 carbon atoms, an optionally substituted cycloalkyloxy group of 5 to 10 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aromatic heterocyclic group, a substituted or unsubstituted fused polycyclic aromatic group, or a substituted or unsubstituted aryloxy group, and adjacent groups may be bonded to each other via a single bond, a substituted or unsubstituted methylene group, an oxygen atom, or a sulfur atom to form a ring.

3. 3. The photoelectric conversion element according to claim 1, wherein, in general formula (1), X is an oxygen atom, and Ar1 and Ar2 may be the same or different from each other and are a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aromatic heterocyclic group, or a substituted or unsubstituted fused polycyclic aromatic group.

4. 4. The photoelectric conversion element according to claim 1, wherein, in general formula (1), Ar1 and Ar2 have a structure selected from the group consisting of the following general formulas (2a) to (2u): 【Transformation 3】 (In the formula, Ar3 is the same as Ar1 and Ar2 in general formula (1), R13 to R15 may be the same as or different from each other and have the same definition as R1 to R12 in general formula (1), The dashed line indicates the binding site. a represents an integer of 0 to 5, b represents an integer of 0 to 4, c represents an integer of 0 to 3, d represents an integer of 0 to 2.

5. A photoelectric conversion element according to claim 1, wherein the highest occupied molecular orbital (HOMO) level of the material for the photoelectric conversion element is −5.8 eV or less.

6. An imaging device comprising the photoelectric conversion element according to any one of claims 1 to 5.

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