Condensed polycyclic aromatic compound, organic semiconductor material, material for photoelectric conversion element, organic thin film, and organic photoelectric conversion element

Abstract

The purpose of the present invention is to provide: a condensed polycyclic aromatic compound that serves as a material for an organic photoelectric conversion element with high EQE and excellent dark current suppression; and an organic semiconductor, a material for a photoelectric conversion element, an organic thin film, and an organic photoelectric conversion element that contain the condensed polycyclic aromatic compound. Provided is a condensed polycyclic aromatic compound represented by formula (1) (in the formula, R1 and R6 each independently represent a substituted or unsubstituted monovalent aromatic hydrocarbon group or a monovalent heteroaromatic group including a substituted or unsubstituted sulfur atom, R2 to R5 each independently represent a substituted or unsubstituted divalent aromatic hydrocarbon group or a divalent heteroaromatic group including a substituted or unsubstituted sulfur atom, and m and n each independently represent 0 or 1).

Description

Fused polycyclic aromatic compounds, organic semiconductor materials, materials for photoelectric conversion elements, organic thin films, and organic photoelectric conversion elements

[0001] The present invention relates to a novel fused polycyclic aromatic compound, an organic semiconductor material, a material for a photoelectric conversion device, an organic thin film, and an organic photoelectric conversion device. More specifically, the present invention relates to a fused polycyclic aromatic compound that is a benzo[b]thieno[2,3-d]thiophene (hereinafter abbreviated as "BTT") derivative, an organic semiconductor material, a material for a photoelectric conversion device, and an organic thin film containing the compound, and an organic photoelectric conversion device containing the organic thin film.

[0002] Organic electronics devices have been the subject of vigorous research and development in recent years because they can be supplied stably as they do not contain rare metals or other such raw materials, and because they have flexibility not found in inorganic materials and can be manufactured by wet film formation methods. Specific examples of organic electronics devices include organic EL elements, organic solar cell elements, organic photoelectric conversion elements, and organic transistor elements. In addition to these, various applications that take advantage of the characteristics of organic compounds as well as the performance of the devices themselves are being investigated.

[0003] Among the above-mentioned devices, organic photoelectric conversion elements are used in optical sensors and the like, and their use in, for example, image sensors has been considered (Patent Document 1). However, when used as an image sensor, it is required to improve the external quantum efficiency (hereinafter abbreviated as EQE), which indicates the degree to which irradiated light is efficiently converted into electrical energy, and to suppress the current value (dark current) when no light is irradiated (Patent Documents 2 and 3).

[0004] WO2022 / 114065WO2018 / 020869WO2019 / 058995 JP 2009-141338 A

[0005] However, among the photoelectric conversion elements using fused polycyclic aromatic compounds reported to date, few can simultaneously satisfy both EQE and dark current. Patent Document 3 reports a fused polycyclic aromatic compound that exhibits excellent EQE when used in a photoelectric conversion element, but there is no mention of dark current, and the inventors' evaluation revealed that a response speed sufficient for practical use could not be obtained. Furthermore, while BTT-based compounds are known to exhibit semiconductor properties when used in organic transistors (Patent Document 4), the various properties of BTT-based compounds when used in photoelectric conversion elements were unknown.

[0006] In view of the above circumstances, an object of the present invention is to provide a fused polycyclic aromatic compound that can be used as a material for an organic photoelectric conversion element having a high EQE and excellent dark current suppression, as well as an organic semiconductor material, a material for a photoelectric conversion element, an organic thin film, and an organic photoelectric conversion element, each containing the fused polycyclic aromatic compound.

[0007] As a result of intensive investigations, the present inventors have found that the above-mentioned problems can be solved by using a novel fused polycyclic aromatic compound with a specific structure having a BTT structure as a central skeleton, and have thus completed the present invention.

[0008] That is, the present invention relates to the following [1] to [4]. [1] A compound represented by the following formula (1): (In formula (1), R １ and R ６ each independently represents a substituted or unsubstituted monovalent aromatic hydrocarbon group or a substituted or unsubstituted monovalent heteroaromatic group containing a sulfur atom; R ２ From R ５ each independently represent a substituted or unsubstituted divalent aromatic hydrocarbon group, or a substituted or unsubstituted divalent heteroaromatic group containing a sulfur atom, and m and n each independently represent 0 or 1. [2] An organic semiconductor material containing the fused polycyclic aromatic compound according to [1]. [3] A material for a photoelectric conversion element containing the fused polycyclic aromatic compound according to [1]. [4] An organic thin film containing the organic semiconductor material according to [2] or the material for a photoelectric conversion element according to [3]. [5] An organic photoelectric conversion element having the organic thin film according to [4]. [6] R １ , R ２ and R３ and a substituent consisting of R ４ , R ５ and R 6 [7] The fused polycyclic aromatic compound according to [1], wherein the substituents consisting of R １ , R ２ and R ３ and a substituent consisting of R ４ , R ５ and R 6 The fused polycyclic aromatic compound according to [1], wherein the substituents are different from each other.

[0009] The present invention can provide a fused polycyclic aromatic compound that can be used as a material for an organic photoelectric conversion element having a high EQE and excellent dark current suppression, as well as a material for a photoelectric conversion element, an organic semiconductor material, an organic thin film, and an organic photoelectric conversion element, each containing the fused polycyclic aromatic compound.

[0010] FIG. 1 is a schematic cross-sectional view showing one embodiment of an organic photoelectric conversion element.

[0011] The present invention will be described in detail below. The description of the constituent elements described herein is based on typical embodiments and specific examples of the present invention, but the present invention is not limited to such embodiments and specific examples.

[0012] [Fused Polycyclic Aromatic Compound] The compound of the present invention is represented by the following formula (1).

[0013] In formula (1), R １ and R ６ represents a substituted or unsubstituted monovalent aromatic hydrocarbon group, or a substituted or unsubstituted monovalent heteroaromatic group containing a sulfur atom. The substituted or unsubstituted aromatic hydrocarbon group is preferably a phenyl group, a naphthyl group, a phenanthrenyl group, or a fluorenyl group, more preferably a phenyl group or a naphthyl group. The substituted or unsubstituted heteroaromatic group containing a sulfur atom is preferably a thienyl group, a benzothienyl group, or a thienothienyl group, more preferably a thienyl group or a benzothienyl group.

[0014] R ２ From R ５each independently represents a substituted or unsubstituted divalent aromatic hydrocarbon group, or a substituted or unsubstituted divalent heteroaromatic group containing a sulfur atom. A divalent aromatic hydrocarbon group is a divalent linking group formed by removing two hydrogen atoms from an aromatic ring of an aromatic compound. When a divalent aromatic hydrocarbon group has a substituent, the substituent is preferably an aromatic hydrocarbon group, and the substitution position is not particularly limited. A divalent heteroaromatic group containing a sulfur atom is a divalent linking group formed by removing two hydrogen atoms from a heteroaromatic ring of a heteroaromatic compound. When a divalent heteroaromatic group has a substituent, the substituent is preferably a C1-6 alkyl group, a C1-6 thioalkyl group, or an aromatic hydrocarbon group, and more preferably a methyl group, a thiomethyl group, a phenyl group, or a naphthyl group, and the substitution position is not particularly limited.

[0015] R ２ From R ５ Specific examples of the divalent aromatic hydrocarbon group represented by include linking groups obtained by removing two hydrogen atoms from an aromatic organic compound selected from benzene, indene, naphthalene, fluorene, phenanthrene, etc. The divalent aromatic hydrocarbon group is preferably a linking group obtained by removing two hydrogen atoms from an aromatic organic compound selected from benzene and naphthalene, and in the case of an aromatic organic compound selected from benzene and naphthalene, these linking groups preferably form a bond at a substitution position represented by the following formula (2):

[0016]

[0017] R ２ From R ５ Specific examples of the divalent heteroaromatic group containing a sulfur atom represented by the formula (3) include a linking group obtained by removing two hydrogen atoms from a heteroaromatic compound selected from thiophene, thienothiophene, benzothiophene, naphthothiophene, etc. The divalent heteroaromatic group is preferably a linking group obtained by removing two hydrogen atoms from a heteroaromatic compound selected from thiophene and benzothiophene, and when the linking group is thiophene or benzothiophene, it is preferable that these linking groups form a bond at the substitution position represented by the formula (3) below.

[0018]

[0019] n and m each independently represent 0 or 1;

[0020] In addition, R １ and R 6 may be the same or different, R ２ and R ５ may be the same or different, and when n and m are each 1, R ３ and R ４ may be the same or different. That is, in one embodiment of the present invention, R １ , R ２ and R ３ and a substituent consisting of R ４ , R ５ and R 6 and the substituents consisting of may be the same or different.

[0021] The fused polycyclic aromatic compound represented by formula (1) can be obtained by coupling a dihalogenated BTT (2,6-dihalogenobenzo[b]thieno[2,3-d]thiophene) represented by the following formula (A) with a boronic acid derivative or a boronic acid ester derivative, and then isolating the target compound by, for example, sublimation purification.

[0022]

[0023] X in formula (A) １ and X ２ represents a halogen atom.

[0024] Dihalogenated BTT represented by formula (A) can be synthesized by a combination of known methods (for example, Japanese Patent No. 7186448 and Chemical Communications, 2012, 48, 3557-3559). As an example, a method for synthesizing dibromo BTT (A1) is shown below.

[0025]

[0026] The method for purifying the fused polycyclic aromatic compound represented by formula (1) is not particularly limited, and known methods such as recrystallization, column chromatography, and vacuum sublimation purification can be used. These methods can also be combined as necessary.

[0027] Specific examples of the fused polycyclic aromatic compound represented by formula (1) are shown below, but the compound is not limited to these examples.

[0028]

[0029]

[0030] [Organic Semiconductor Material] The organic semiconductor material contains a fused polycyclic aromatic compound represented by formula (1). The organic semiconductor material may contain components other than the fused polycyclic aromatic compound represented by formula (1) as long as the effects of the present invention are not impaired. However, it is preferable that the organic semiconductor material contains only the fused polycyclic aromatic compound represented by formula (1). The content of the fused polycyclic aromatic compound represented by formula (1) in the organic semiconductor material is preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, particularly preferably 98% by mass or more, and most preferably 99% by mass or more, based on the mass of the entire organic semiconductor material. Other components that can be used in combination with the fused polycyclic aromatic compound represented by formula (1) are not particularly limited. The organic semiconductor material may contain one or more fused polycyclic aromatic compounds represented by formula (1) alone or in combination.

[0031] The organic semiconductor material is suitable for use as a hole transport material in various organic electronic devices such as organic thin-film solar cell elements, organic EL elements, organic transistor elements, and organic photoelectric conversion elements.

[0032] [Photoelectric conversion element material] The organic semiconductor material is particularly suitable for use as a hole transport material for an organic photoelectric conversion element (hereinafter also referred to as "photoelectric conversion element material"). By using a photoelectric conversion element material containing a fused polycyclic aromatic compound represented by formula (1) as a hole transport material for a photoelectric conversion element, a photoelectric conversion element having a high EQE and excellent dark current suppression can be realized.

[0033] [Organic Thin Film] The organic thin film contains the organic semiconductor material. The film thickness of the organic thin film may be selected depending on the application, but is usually 1 nm to 1 μm, preferably 5 nm to 500 nm, and more preferably 10 nm to 500 nm. Methods for forming the organic thin film include dry processes such as vapor deposition (methods using the photoelectric conversion element material as is) and various solution processes (methods using a solution in which the photoelectric conversion element material is dissolved and / or dispersed in an organic solvent, etc.). Solution processes include, for example, spin coating, drop casting, dip coating, spraying, relief printing methods such as flexographic printing and resin relief printing, lithographic printing methods such as offset printing, dry offset printing and pad printing, intaglio printing methods such as gravure printing, stencil printing methods such as screen printing, mimeograph printing and ring graph printing, inkjet printing, microcontact printing, etc., as well as methods combining a plurality of these methods. When forming a film by a solution process, it is preferable to form a thin film by evaporating the solvent after the above coating or printing.

[0034] The organic thin film has carrier transport properties, and thus can be used in organic semiconductor elements such as organic transistor elements and organic photoelectric conversion elements (organic thin film solar cells, photosensors, image sensors, photocounters, LIDAR, etc.) by controlling the transport of holes injected from an electrode or carriers generated by absorbed light.

[0035] [Organic Photoelectric Conversion Element] An organic photoelectric conversion element is an element composed of an organic semiconductor material, electrodes, etc., and converts light into electricity. FIG. 1 shows an example of an organic photoelectric conversion element. The organic photoelectric conversion element 10 comprises, in this order, a substrate 1, a first electrode 2, an electron blocking layer 3, a photoelectric conversion layer 4, a hole blocking layer 5, and a second electrode 6. The organic photoelectric conversion element 10 is characterized in that both or one of the electron blocking layer 3 and the photoelectric conversion layer 4 have an organic thin film containing the above-mentioned photoelectric conversion element material as a hole transport material. The organic photoelectric conversion element of the present invention is not limited to the structure shown in FIG. 1, and layers can be added or omitted as necessary. The organic photoelectric conversion element shown in FIG. 1 can be used, for example, as an organic photoelectric conversion element for imaging.

[0036] -Substrate 1- The substrate 1 is a member that supports the organic photoelectric conversion element 10. There are no particular limitations on the material of the substrate 1, and for example, a substrate made of glass, transparent plastic, quartz, or the like can be used. Note that, when light is incident from the second electrode 6 side in FIG. 1, the substrate 1 does not necessarily have to be transparent. Here, "having transparency" means having excellent transmittance for light of a specific wavelength to be converted into current. Furthermore, a substrate may be further disposed on the outer side of the second electrode 6 (the side of the second electrode 6 that is not in contact with the hole-blocking layer 5), but at least one of the substrates disposed on the outer side of the substrate 1 and the second electrode 6 must be transparent.

[0037] - First electrode 2, second electrode 6 - The first electrode 2 and the second electrode 6 have the function of collecting holes and electrons generated in the photoelectric conversion layer 4. Since they also need the function of allowing light to enter the photoelectric conversion layer 4, at least one of the first electrode 2 and the second electrode 6 needs to be transparent. There are no particular limitations on the material of the first electrode 2 and the second electrode 6 as long as it is conductive, but examples thereof include ITO, IZO, SnO ２ , ATO (antimony-doped tin oxide), ZnO, AZO (Al-doped zinc oxide), GZO (gallium-doped zinc oxide), TiO ２ Examples of the conductive material include transparent conductive materials such as FTO, metals such as gold, silver, platinum, chromium, aluminum, iron, cobalt, nickel, and tungsten, inorganic conductive materials such as copper iodide and copper sulfide, and conductive polymers such as polythiophene, polypyrrole, and polyaniline. The first electrode 2 and the second electrode 6 may contain a mixture of two or more of these materials as necessary, or may be a laminate of two or more layers.

[0038] - Electron Blocking Layer 3 - The electron blocking layer 3 is provided to suppress dark current that occurs when electrons are injected from one electrode into the photoelectric conversion layer 4 when a bias voltage is applied between the two electrodes. The electron blocking layer 3 also functions as a hole transport layer that transports holes generated by charge separation in the photoelectric conversion layer 4 to the electrode. The electron blocking layer 3 can be arranged as a single layer or multiple layers as needed.

[0039] The electron blocking layer 3 may contain a P-type organic semiconductor material, which is a hole transport material. The P-type organic semiconductor material contains a fused polycyclic aromatic compound represented by the above formula (1). A material for a photoelectric conversion element is preferable, but other P-type organic semiconductor materials may also be used.

[0040] Other p-type organic semiconductor materials that can be used include, for example, compounds having a condensed polycyclic aromatic group such as naphthalene, anthracene, phenanthrene, pyrene, chrysene, naphthacene, triphenylene, perylene, fluoranthene, fluorene, and indene; compounds having a π-electron-rich aromatic group such as cyclopentadiene derivatives, furan derivatives, thiophene derivatives, pyrrole derivatives, benzofuran derivatives, benzothiophene derivatives, dinaphthothienothiophene derivatives, indole derivatives, pyrazoline derivatives, dibenzofuran derivatives, dibenzothiophene derivatives, and carbazole derivatives; and aromatic amine derivatives, styrylamine derivatives, benzidine derivatives, porphyrin derivatives, phthalocyanine derivatives, and quinacridone derivatives.

[0041] Photoelectric Conversion Layer 4 The photoelectric conversion layer 4 is a layer in which holes and electrons are generated by charge separation of excitons generated by incident light. The photoelectric conversion layer 4 may be formed solely of a photoelectric conversion material, or may be formed in combination with a P-type organic semiconductor material, which is a hole-transporting material, or an N-type organic semiconductor material, which is an electron-transporting material. Two or more P-type organic semiconductor materials may be used, or two or more N-type organic semiconductor materials may be used. It is desirable that one or more of the photoelectric conversion material, P-type organic semiconductor material, and N-type organic semiconductor material contained in the photoelectric conversion layer 4 contain a dye material that has the function of absorbing light of a desired wavelength in the visible region. In a preferred embodiment, a material for a photoelectric conversion element containing a fused polycyclic aromatic compound represented by formula (1) is used as the P-type organic semiconductor material, which is a hole-transporting material.

[0042] The photoelectric conversion material may be any material that generates excitons in response to incident light, and examples of the photoelectric conversion material that can be used include compounds having a condensed polycyclic aromatic group such as naphthalene, anthracene, phenanthrene, pyrene, chrysene, naphthacene, triphenylene, perylene, fluoranthene, fluorene, and indene; compounds having a π-electron-rich aromatic group such as cyclopentadiene derivatives, furan derivatives, thiophene derivatives, pyrrole derivatives, benzofuran derivatives, benzothiophene derivatives, dinaphthothienothiophene derivatives, indole derivatives, pyrazoline derivatives, dibenzofuran derivatives, dibenzothiophene derivatives, carbazole derivatives, and indolocarbazole derivatives; aromatic amine derivatives, styrylamine derivatives, benzidine derivatives, porphyrin derivatives, phthalocyanine derivatives, and quinacridone derivatives. From the viewpoint of the utilization efficiency of incident light, a material with a high absorption coefficient is preferred, and for example, pyrromethene derivatives, porphyrin derivatives, subporphyrin derivatives, phthalocyanine derivatives, subphthalocyanine derivatives, quinacridone derivatives, pyrrolopyrrole derivatives, coumarin derivatives, perylene derivatives, and aromatic amine derivatives can be used.

[0043] When the above-mentioned photoelectric conversion element material is used as a P-type organic semiconductor material, it may be used in combination with other P-type organic semiconductor materials, or two or more of the above-mentioned photoelectric conversion element materials may be used. Examples of other P-type organic semiconductor materials include compounds having a condensed polycyclic aromatic group such as naphthalene, anthracene, phenanthrene, pyrene, chrysene, naphthacene, triphenylene, perylene, fluoranthene, fluorene, and indene, cyclopentadiene derivatives, furan derivatives, thiophene derivatives, pyrrole derivatives, benzofuran derivatives, benzothiophene derivatives, dinaphthothienothiophene derivatives, indole derivatives, pyrazoline derivatives, dibenzofuran derivatives, dibenzothiophene derivatives, carbazole derivatives, and compounds having a π-electron-rich aromatic group such as indolocarbazole derivatives, aromatic amine derivatives, styrylamine derivatives, benzidine derivatives, porphyrin derivatives, phthalocyanine derivatives, and quinacridone derivatives. Examples of polymeric P-type organic semiconductor materials include polyphenylene vinylene derivatives, polyparaphenylene derivatives, polyfluorene derivatives, polyvinyl carbazole derivatives, and polythiophene derivatives. The polymeric P-type organic semiconductor material may be mixed with the photoelectric conversion element material of the present invention or a non-polymeric P-type organic semiconductor material, or two or more polymeric P-type organic semiconductor materials may be mixed and used.

[0044] The N-type organic semiconductor material may be any material having electron transport properties, and examples thereof include naphthalene tetracarboxylic acid diimide, perylene tetracarboxylic acid diimide, fullerenes, and azole derivatives such as imidazole, thiazole, thiadiazole, oxazole, oxadiazole, and triazole. One or more selected from these N-type organic semiconductor materials may be used alone or in combination.

[0045] -Hole Blocking Layer 5- The hole blocking layer 5 is provided to suppress dark current generated when holes are injected from one electrode into the photoelectric conversion layer 4 when a bias voltage is applied between the two electrodes. The hole blocking layer 5 also functions as an electron transport layer that transports electrons generated by charge separation in the photoelectric conversion layer 4 to the electrode. The hole blocking layer 5 may have a single layer or multiple layers as necessary. The hole blocking layer 5 can be made of an N-type organic semiconductor material having electron transport properties. The N-type organic semiconductor material may be any material having electron transport properties, and examples thereof include polycyclic aromatic polycarboxylic anhydrides such as naphthalene tetracarboxylic diimide and perylene tetracarboxylic diimide, and imidized products thereof; fullerenes such as C60 and C70; azole derivatives such as imidazole, thiazole, thiadiazole, oxazole, oxadiazole, and triazole; tris(8-quinolinolato)aluminum(III) derivatives; phosphine oxide derivatives; nitro-substituted fluorene derivatives; diphenylquinone derivatives; thiopyran dioxide derivatives; carbodiimide; fluorenylidenemethane derivatives; anthraquinodimethane and anthrone derivatives; bipyridine derivatives; quinoline derivatives; and indolocarbazole derivatives. One or more of these N-type organic semiconductor materials may be used alone or in combination.

[0046] The organic photoelectric conversion element 10 can be used in solar cells, optical sensors, image sensors, photocounters, LIDARs, and the like.

[0047] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. In the examples, "parts" means parts by mass, and "%" means % by mass.

[0048] [Example 1: Synthesis of condensed polycyclic aromatic compound No. 2] DibromoBTT (4.4 parts) synthesized by a known method, a boronic acid derivative represented by the following formula (B-1) (10.0 parts) synthesized by a known method, tripotassium phosphate (27.5 parts), and tetrakis(triphenylphosphine)palladium (0.58 parts) were added to DMF (200 parts), and the mixture was stirred at 80°C for 5 hours under a nitrogen atmosphere. The resulting reaction solution was cooled to room temperature, water was added, and the resulting solid was collected by filtration. The resulting solid was washed with acetone, dried, and purified by sublimation to obtain the condensed polycyclic aromatic compound represented by No. 2 of the above specific example (4.3 parts, yield 52%) as a yellow solid.

[0049]

[0050] Example 2 Synthesis of No. 11 Condensed Polycyclic Aromatic Compound A condensed polycyclic aromatic compound (4.1 parts, yield 48%) represented by specific example No. 11 was obtained in the same manner as in Example 1, except that the boronic acid derivative (10.0 parts) represented by formula (B-1) was changed to a pinacol borate derivative (10.0 parts) represented by the following formula (B-2) synthesized by a known method.

[0051]

[0052] Example 3 Synthesis of Condensed Polycyclic Aromatic Compound No. 6 A condensed polycyclic aromatic compound represented by specific example No. 6 (3.8 parts, yield 48%) was obtained in the same manner as in Example 1, except that the boronic acid derivative represented by formula (B-1) (10.0 parts) was changed to a pinacol borate derivative represented by the following formula (B-3) (10.0 parts), which had been synthesized by a known method.

[0053]

[0054] Example 4 Synthesis of No. 14 Condensed Polycyclic Aromatic Compound A specific example of No. 14 (4.2 parts, yield 55%) was obtained in the same manner as in Example 1, except that the boronic acid derivative (10.0 parts) represented by formula (B-1) was changed to a pinacol borate derivative (10.0 parts) represented by the following formula (B-4), which had been synthesized by a known method.

[0055]

[0056] [Example 5: Synthesis of No. 33 fused polycyclic aromatic compound] DibromoBTT (4.4 parts) synthesized by a known method, a boronic acid derivative represented by the following formula (B-5) (5.0 parts) synthesized by a known technique, tripotassium phosphate (27.5 parts), and tetrakis(triphenylphosphine)palladium (0.58 parts) were added to DMF (200 parts), and the mixture was stirred at 80°C for 3 hours under a nitrogen atmosphere. The resulting reaction solution was cooled to room temperature, water was added, and the resulting yellow-white solid was collected by filtration. The resulting yellow-white solid, a boronic acid derivative represented by the above formula (B-2) (5.0 parts), tripotassium phosphate (27.5 parts), and tetrakis(triphenylphosphine)palladium (0.58 parts) were added to DMF (200 parts), and the mixture was stirred at 80°C for 3 hours under a nitrogen atmosphere. The resulting reaction solution was cooled to room temperature, water was added, and the resulting solid was collected by filtration. The obtained solid was washed with acetone, dried, and purified by sublimation to obtain a condensed polycyclic aromatic compound represented by Specific Example No. 33 (1.0 part, yield 13%) as a yellow solid.

[0057]

[0058] [Example 6: Synthesis of No. 34 fused polycyclic aromatic compound] DibromoBTT (4.4 parts) synthesized by a known method, a boronic acid derivative represented by the above formula (B-2) (5.0 parts) synthesized by a known method, tripotassium phosphate (27.5 parts), and tetrakis(triphenylphosphine)palladium (0.58 parts) were added to DMF (200 parts), and the mixture was stirred at 80°C for 3 hours under a nitrogen atmosphere. The resulting reaction solution was cooled to room temperature, water was added, and the resulting yellow-white solid was collected by filtration. The resulting yellow-white solid, a boronic acid derivative represented by the above formula (B-5) (5.0 parts), tripotassium phosphate (27.5 parts), and tetrakis(triphenylphosphine)palladium (0.58 parts) were added to DMF (200 parts), and the mixture was stirred at 80°C for 3 hours under a nitrogen atmosphere. The resulting reaction solution was cooled to room temperature, water was added, and the resulting solid was collected by filtration. The obtained solid was washed with acetone, dried, and purified by sublimation to obtain a condensed polycyclic aromatic compound represented by Specific Example No. 34 (1.2 parts, yield 16%) as a yellow solid.

[0059] Example 7 Synthesis of Condensed Polycyclic Aromatic Compound No. 32 A condensed polycyclic aromatic compound (1.6 parts, yield 20%) represented by specific example No. 32 was obtained in the same manner as in Example 6, except that the boronic acid derivative (5.0 parts) represented by formula (B-5) was changed to a pinacol borate derivative (5.0 parts) represented by the following formula (B-6), which had been synthesized by a known method.

[0060] Example 8: Preparation of photoelectric conversion element A On a glass substrate on which an electrode made of ITO with a film thickness of 70 nm was formed, an electron blocking layer was formed by depositing a photoelectric conversion element A at a substrate temperature of room temperature and a vacuum degree of 4.0×10 －５ A film of CzBDF (manufactured by Tokyo Chemical Industry Co., Ltd.) was formed to a thickness of 10 nm under the condition of 0.05 Pa. Next, as a photoelectric conversion layer, the compound represented by No. 2 of the specific example obtained in Example 1, Cl ６ -SubPc-OPh (manufactured by Lumitec) and fullerene (C60, manufactured by Tokyo Chemical Industry Co., Ltd.) were co-evaporated at a deposition rate ratio of 4:4:2 to form an organic thin film with a thickness of 230 nm. Subsequently, dpy-NDI (manufactured by Tokyo Chemical Industry Co., Ltd.) was evaporated to a thickness of 10 nm to form a hole-blocking layer. Finally, an aluminum film was formed to a thickness of 100 nm as an electrode to prepare photoelectric conversion element A.

[0061]

[0062] [Example 9: Preparation of photoelectric conversion element B] Photoelectric conversion element B was prepared in the same manner as in Example 8, except that compound No. 11 obtained in Example 2 was used instead of compound No. 2 of the specific example obtained in Example 1.

[0063] Example 10: Preparation of photoelectric conversion element C Photoelectric conversion element C was prepared in the same manner as in Example 8, except that compound No. 6 obtained in Example 3 was used instead of compound No. 2 of the specific example obtained in Example 1.

[0064] [Example 11: Preparation of photoelectric conversion element D] Photoelectric conversion element D was prepared in the same manner as in Example 8, except that compound No. 14 obtained in Example 4 was used instead of compound No. 2 of the specific example obtained in Example 1.

[0065] [Example 12: Preparation of photoelectric conversion element E] Photoelectric conversion element E was prepared in the same manner as in Example 8, except that compound No. 33 obtained in Example 5 was used instead of compound No. 2 of the specific example obtained in Example 1.

[0066] [Example 13: Preparation of photoelectric conversion element F] Photoelectric conversion element F was prepared in the same manner as in Example 8, except that compound No. 34 obtained in Example 6 was used instead of compound No. 2 of the specific example obtained in Example 1.

[0067] Example 14 Preparation of Photoelectric Conversion Element G Photoelectric conversion element G was prepared in the same manner as in Example 8, except that compound No. 32 obtained in Example 7 was used instead of compound No. 2 of the specific example obtained in Example 1.

[0068] Comparative Example 1: Preparation of photoelectric conversion element H According to the method described in Patent Document 3, a compound represented by the following formula (No. C1) was obtained.

[0069]

[0070] A photoelectric conversion element H was prepared in the same manner as in Example 8, except that the compound represented by No. C1 was used instead of the compound represented by No. 2.

[0071] (Evaluation of Organic Photoelectric Conversion Elements) (a) External Quantum Efficiency (EQE) Evaluation Photoelectric conversion elements were evaluated based on the examples of WO2018 / 105269. Specifically, for each of photoelectric conversion elements A, B, C, D, E, F, G, and H, a 2.0 × 10 ５ A voltage was applied to achieve an intensity of 1000 V / cm, and the EQE and dark current of the photoelectric conversion at 550 nm were measured. The results are shown in Table 1. Evaluation criteria: EQE: 75% or more; A; 70% or more but less than 75%; B; less than 70%; C; Dark current: 5.0×10 －１１ A / cm ２ If less than: A 5.0 x 10 －１１ Above 1.0 x 10 －１０ A / cm ２ If less than: B 1.0 x 10－１０ Above 1.0 x 10 －６ A / cm ２ If less than C 1.0 × 10 －６ A / cm ２ In the above cases: D In practice, the larger the EQE, the more efficiently the irradiated light can be converted into electrical energy, meaning that "A" is superior and "C" is inferior. The smaller the dark current, the more the current value when light irradiation is turned off can be suppressed, meaning that "A" is superior and "D" is inferior.

[0072]

[0073] As shown in Table 1, the photoelectric conversion elements of Examples 8 to 14 have sufficiently low dark current and can maintain a high EQE. On the other hand, the photoelectric conversion element of Comparative Example 1 has a significantly poor dark current value, indicating that it is difficult to achieve both a high EQE and a low dark current.

[0074] By using the fused polycyclic aromatic compound represented by formula (1), it is possible to provide an organic semiconductor device (for example, a photoelectric conversion element, an optical sensor, etc.) that can achieve both a low dark current and a high EQE.

[0075] REFERENCE SIGNS LIST 1 Substrate 2 First electrode 3 Electron blocking layer 4 Photoelectric conversion layer 5 Hole blocking layer 6 Second electrode 10 Organic photoelectric conversion element

Claims

1. The following formula (1): (In the formula, R １ and R ６ each independently represents a substituted or unsubstituted monovalent aromatic hydrocarbon group or a substituted or unsubstituted monovalent heteroaromatic group containing a sulfur atom; R ２ From R ５ each independently represent a substituted or unsubstituted divalent aromatic hydrocarbon group, or a substituted or unsubstituted divalent heteroaromatic group containing a sulfur atom, and m and n each independently represent 0 or 1.

2. An organic semiconductor material containing the fused polycyclic aromatic compound according to claim 1.

3. A material for photoelectric conversion devices containing the fused polycyclic aromatic compound according to claim 1.

4. An organic thin film comprising the organic semiconductor material according to claim 2 or the material for a photoelectric conversion element according to claim 3.

5. An organic photoelectric conversion element having the organic thin film according to claim 4.

6. R １ , R ２ and R ３ and a substituent consisting of R ４ , R ５ and R 6 The fused polycyclic aromatic compound according to claim 1 , wherein the substituents consisting of 7. R １ , R ２ and R ３ and a substituent consisting of R ４ , R ５ and R 6 The fused polycyclic aromatic compound according to claim 1 , wherein the substituents consisting of

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