Condensed polycyclic aromatic compounds, organic semiconductor materials, materials for photoelectric devices, organic thin films, and organic photoelectric devices

Abstract

The objective is to provide condensed polycyclic aromatic compounds that serve as organic photoelectric conversion materials with excellent external quantum yield (EQE), dark current, and response speed when used as photoelectric conversion elements, as well as materials for photoelectric conversion elements, organic thin films, and organic photoelectric conversion elements using the same. [Solution] A condensed polycyclic aromatic compound represented by the following formula (1) is provided. TIFF2026070575000014.tif13170 (In the formula, X is a divalent linking group obtained by removing two hydrogen atoms from benzene, biphenyl, or naphthalene.)

Description

[Technical Field]

[0001] The present invention relates to a novel condensed polycyclic aromatic compound, and to an organic semiconductor material, a material for a photoelectric conversion element, an organic thin film, and an organic photoelectric conversion element using the same. [Background technology]

[0002] Organic electronic devices are attracting significant research and development in recent years because they can be supplied stably as they do not contain rare metals or other materials, possess flexibility not found in inorganic materials, and can be manufactured using wet deposition methods. For example, organic thin-film devices such as organic EL elements, field-effect transistors, and organic photoelectric converters are gaining attention, and various organic electronic materials, such as condensed polycyclic aromatic compounds used in these thin-film devices, are being researched and developed.

[0003] Of the above devices, organic photoelectric conversion elements are used in light sensors and the like, and their use in image sensors is being considered (Patent Document 1). However, when used as an image sensor, it is important to improve the external quantum efficiency (EQE), which represents the degree to which the irradiated light is efficiently converted into electrical energy, and to suppress the current value when light is not irradiated (dark current). In addition to these characteristics, image sensors are required to have a fast response speed when switching light irradiation ON / OFF in order to capture moving objects clearly (Patent Document 2).

[0004] To satisfy these device characteristics, organic photoelectric conversion elements are currently being researched to improve the above-mentioned characteristics by using a bulk heterojunction structure with a mixed film of P-type and N-type organic semiconductors for the photoelectric conversion layer. In this research and development, the use of BTBT derivatives, which are known to exhibit high hole transport characteristics, as the P-type organic semiconductor is being considered (Patent Document 3). [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] International Publication No. 2022 / 114065 [Patent Document 2] Patent No. 6674547 [Patent Document 3] International Publication No. 2016 / 185858 [Patent Document 4] U.S. Patent Application Publication No. 2016 / 0043329 [Non-patent literature]

[0006] [Non-Patent Document 1] Chem.Eur.J.2018,24,16595-16602. [Overview of the project] [Problems that the invention aims to solve]

[0007] However, few photoelectric conversion elements using BTBT compounds reported to date can simultaneously satisfy both EQE and dark current requirements, and furthermore, none have achieved a response speed sufficient for practical use.

[0008] Non-patent document 1 reports a compound with two BTBT groups arranged in the molecule, and while high hole transport characteristics have been observed when used in organic thin-film transistors, there have been no examples of its use in photoelectric conversion elements, and its applicability to photoelectric conversion elements was unknown.

[0009] In view of the above circumstances, the present invention aims to provide a condensed polycyclic aromatic compound that serves as an organic photoelectric conversion material with excellent EQE, dark current, and response speed when used as a photoelectric conversion element, as well as a material for a photoelectric conversion element, an organic thin film, and an organic photoelectric conversion element using the same. [Means for solving the problem]

[0010] As a result of intensive studies, the inventors of the present invention have developed a novel condensed polycyclic aromatic compound in which two BTBTs are arranged in the molecule and thienyl groups bonded at the 3-position are arranged at both ends of the molecule, and have clarified that when used in an organic optoelectronic conversion device, it exhibits good optoelectronic conversion characteristics, found that the above problems are solved, and completed the present invention.

[0011] That is, the present invention relates to the following [1] to [7]. [1] A condensed polycyclic aromatic compound represented by the following formula (1). [Chemical formula] (In formula (1), X is a divalent linking group obtained by removing two hydrogen atoms from benzene, biphenyl, or naphthalene.) [2] The condensed polycyclic aromatic compound according to [1], wherein in formula (1), X is selected from the group represented by the following formula (2) and the group represented by the following formula (3). [Chemical formula] (In formula (2), n represents 1 or 2.) [3] The condensed polycyclic aromatic compound according to [2], wherein n is 1 in formula (2). [4] An organic semiconductor material containing the condensed polycyclic aromatic compound according to any one of [1] to [3]. [5] A material for a photoelectric conversion device containing the condensed polycyclic aromatic compound according to any one of [1] to [3]. [6] An organic thin film containing the condensed polycyclic aromatic compound according to any one of [1] to [3] or the material for a photoelectric conversion device according to [5]. [7] An organic optoelectronic conversion device having the organic thin film according to [6]. [Advantages of the Invention]

[0012] The present invention can provide a condensed polycyclic aromatic compound that can give excellent EQE, dark current, and response speed when used in a photoelectric conversion device, and a material for a photoelectric conversion device, an organic thin film, and an organic optoelectronic conversion device using the same. [Brief explanation of the drawing]

[0013] [Figure 1] This is a schematic cross-sectional view showing one embodiment of an organic photoelectric conversion element. [Modes for carrying out the invention]

[0014] [Fused polycyclic aromatic compound] The condensed polycyclic aromatic compound of the present invention is represented by the following formula (1). [ka]

[0015] In formula (1), X represents a divalent linking group obtained by removing two hydrogen atoms from benzene, biphenyl, or naphthalene.

[0016] X is preferably one of the groups represented by the following formula (2) and the following formula (3). In formula (2), n represents 1 or 2, and preferably n is 1.

[0017] [ka]

[0018] The carbon atom in formula (1) preferably does not have any further substituents.

[0019] The synthesis method for the condensed polycyclic aromatic compound represented by formula (1) is described below. However, the synthesis method for the condensed polycyclic aromatic compound represented by formula (1) is not limited to the synthesis method shown below. The condensed polycyclic aromatic compound represented by formula (1) can be synthesized from dihalogenated BTBT (2,7-dihalogenobenzo[b]benzo[4,5]thieno[2,3-b]thiophene) represented by the following formula (S), which can be synthesized by known methods. First, an intermediate compound represented by formula (M) can be synthesized by carrying out a coupling reaction using 1 equivalent amount of 3-thiopheneboronic acid represented by the following formula (T). Next, the condensed polycyclic aromatic compound represented by formula (1) can be synthesized by carrying out a coupling reaction with the intermediate compound represented by formula (M) using half an equivalent amount of a bisboronic acid derivative represented by the following formula (U).

[0020] [ka]

[0021] Z in equation (S) 1 and Z 2 Each of these independently represents bromine or iodine, and R in formulas (T) and (S) 1 , R 2 and R 3 Each of the R's independently represents either hydrogen or an alkyl group, and there are two R's. 1 Allies, R 2 Both and R 3 These elements may join with each other to form a ring.

[0022] The method for purifying the condensed 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 employed. These methods can also be combined as needed.

[0023] Specific examples of condensed polycyclic aromatic compounds represented by formula (1) are shown below, but the compound is not limited to these examples.

[0024] [ka]

[0025] [Organic semiconductor materials] The organic semiconductor material contains a condensed polycyclic aromatic compound represented by formula (1). The organic semiconductor material may contain components other than the compound represented by formula (1) as long as the effects of the present invention are not impaired, but it is preferable that it contains only the compound represented by formula (1). The content of the condensed 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. Examples of organic semiconductor devices that can use materials for organic semiconductor devices containing a condensed polycyclic aromatic compound represented by formula (1) include organic EL devices, field-effect transistor devices, organic thin-film solar cell devices, and photoelectric conversion devices.

[0026] [Materials for photoelectric conversion elements] The material for the photoelectric conversion element contains a condensed polycyclic aromatic compound represented by formula (1). The material for the photoelectric conversion element may contain components other than the compound represented by formula (1) as long as the effects of the present invention are not impaired, but it is preferable to contain only the compound represented by formula (1). The content of the compound represented by formula (1) in the material for the photoelectric conversion element 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. The condensed polycyclic aromatic compound represented by formula (1) can be contained as a single compound or in combination of multiple compounds. Photoelectric conversion materials containing condensed polycyclic aromatic compounds represented by formula (1) can be used as hole transport materials in photoelectric conversion elements to realize photoelectric conversion elements with excellent EQE, dark current, and response speed.

[0027] [Organic thin film] The organic thin film is characterized by containing the above-mentioned condensed polycyclic aromatic compound. The thickness of the organic thin film can be selected according to its 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 that use the photoelectric conversion element material as is) and various solution processes (methods that use a solution in which the photoelectric conversion element material is dissolved and / or dispersed in an organic solvent, etc.), but it is preferable to use a dry process such as vapor deposition.

[0028] [Organic photoelectric conversion element] An organic photoelectric element is an element composed of an organic semiconductor material and electrodes, and is an element that converts light into electricity. Figure 1 shows an example of an organic photoelectric element. The organic photoelectric element 10 comprises 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 in this order. The organic photoelectric element 10 is characterized in that the photoelectric conversion layer 4 has an organic thin film containing the above-mentioned photoelectric element material as a hole transporting material. The organic photoelectric element of the present invention is not limited to the structure shown in Figure 1, and layers can be added or omitted as needed.

[0029] -Circuit board 1- The substrate 1 is a component that supports the organic photoelectric conversion element 10. There are no particular restrictions on the material of the substrate 1; for example, it can be made of glass, transparent plastic, quartz, or the like. Furthermore, when light is incident from the second electrode 6 side in Figure 1, the substrate 1 does not necessarily have to be transparent. Here, "transparent" means having excellent transmittance of light of a specific wavelength to be converted into electric current. In addition, a substrate may be placed outside the second electrode 6, but at least one of the substrate 1 and the substrate outside the second electrode 6 must be transparent.

[0030] -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 it is also necessary to allow light to enter the photoelectric conversion layer 4, at least one of the first electrode 2 and the second electrode 6 must be transparent. The material of the first electrode 2 and the second electrode 6 is not particularly limited as long as it is conductive, but examples include conductive transparent materials such as ITO, IZO, SnO2, ATO (antimond-doped tin oxide), ZnO, AZO (al-doped zinc oxide), GZO (gallium-doped zinc oxide), TiO2 and FTO; metals such as gold, silver, platinum, chromium, aluminum, iron, cobalt, nickel and tungsten; inorganic conductive substances 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 multiple types of these materials as needed, or they may be laminated in two or more layers.

[0031] -Electronic Block Layer 3- The electron blocking layer 3 is provided to suppress the dark current generated when electrons are injected from one electrode into the photoelectric conversion layer 4 when a bias voltage is applied between the two electrodes. It also functions as a hole transport layer, transporting holes generated by charge separation in the photoelectric conversion layer 4 to the electrodes. The electron blocking layer 3 can be arranged as a single layer or in multiple layers as needed.

[0032] The electron blocking layer 3 may include a P-type organic semiconductor material that is a hole transport material. Examples of P-type organic semiconductor materials include compounds having condensed polycyclic aromatic groups such as naphthalene, anthracene, phenanthrene, pyrene, chrysene, naphthacene, triphenylene, perylene, fluorantene, fluorene, and indene; compounds having π-electron-excess aromatic groups such as cyclopentadiene derivatives, furan derivatives, thiophene derivatives, pyrrole derivatives, benzofuran derivatives, benzodifuran derivatives, benzothiophene derivatives, benzodithiophene derivatives, dibenzothienothiophene derivatives, dinaphthothienothiophene derivatives, indole derivatives, pyrazoline derivatives, dibenzofuran derivatives, dibenzothiophene derivatives, carbazole derivatives, and indrocarbazole derivatives; and aromatic amine derivatives, styrylamine derivatives, benzidine derivatives, porphyrin derivatives, phthalocyanine derivatives, and quinacridone derivatives.

[0033] -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 is formed by combining a photoelectric conversion material, a P-type organic semiconductor material which is a hole transport material, and an N-type organic semiconductor material which is an electron transport material. As the P-type organic semiconductor material which is a hole transport material, a photoelectric conversion element material containing a condensed polycyclic aromatic compound represented by formula (1) is used. Furthermore, the P-type organic semiconductor material may be used alone or in combination of two or more types, and the N-type organic semiconductor material may be used alone or in combination of two or more types. 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 have the function of absorbing light of a desired wavelength in the visible region.

[0034] As the photoelectric conversion material, any material that generates excitons upon incident light can be used. For example, compounds having condensed polycyclic aromatic groups such as naphthalene, anthracene, phenanthrene, pyrene, chrysene, naphthacene, triphenylene, perylene, fluorantene, fluorene, and indene; π-electron-rich polycyclic aromatic compounds such as cyclopentadiene derivatives, furan derivatives, thiophene derivatives, pyrrole derivatives, benzofuran derivatives, benzodifuran derivatives, benzothiophene derivatives, benzodithiophene derivatives, dibenzothienothiophene derivatives, dinaphthothienothiophene derivatives, indole derivatives, pyrazoline derivatives, dibenzofuran derivatives, dibenzothiophene derivatives, carbazole derivatives, and indrocarbazole derivatives; aromatic amine derivatives, styrylamine derivatives, benzidine derivatives, porphyrin derivatives, phthalocyanine derivatives, quinacridone derivatives, benzothiazole derivatives, and benzobisthiadiazole derivatives can be used. From the viewpoint of efficient utilization of incident light, materials with a high absorption coefficient are preferred. For example, pyromethene derivatives, porphyrin derivatives, subporphyrin derivatives, phthalocyanine derivatives, subphthalocyanine derivatives, quinacridone derivatives, pyrrolopyrrole derivatives, coumarin derivatives, perylene derivatives, aromatic amine derivatives, benzothiazole derivatives, and benzobisthiadiazole derivatives can be used.

[0035] The p-type organic semiconductor material may be a photoelectric device material containing a condensed polycyclic aromatic compound represented by formula (1), either alone or in combination with other p-type organic semiconductor materials. Furthermore, the p-type organic semiconductor material may use two or more of the above-mentioned photoelectric device materials. Other P-type organic semiconductor materials that can be used include compounds having condensed polycyclic aromatic groups such as naphthalene, anthracene, phenanthrene, pyrene, chrysene, naphthacene, triphenylene, perylene, fluorantene, fluorene, and indene; compounds having π-electron-excess aromatic groups 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, indolocarbazole derivatives; aromatic amine derivatives, styrylamine derivatives, benzidine derivatives, porphyrin derivatives, phthalocyanine derivatives, and quinacridone derivatives. Furthermore, other P-type organic semiconductor materials may be polymer-type P-type organic semiconductor materials. Examples of polymer-type P-type organic semiconductor materials include polyphenylene vinylene derivatives, polyparaphenylene derivatives, polyfluorene derivatives, polyvinylcarbazole derivatives, and polythiophene derivatives. Polymer-type P-type organic semiconductor materials may be mixed with the photoelectric conversion element material or non-polymer-type P-type organic semiconductor material of the present invention, or two or more polymer-type P-type organic semiconductor materials may be mixed and used.

[0036] The N-type organic semiconductor material can be any material that has electron transport properties. Examples include naphthalenetetracarboxylate diimide, perylenetetracarboxylate diimide, fullerenes, imidazole, thiazole, thiadiazole, oxazole, oxadiazole, and azole derivatives such as triazole. One or more of these N-type organic semiconductor materials can be used individually or in combination.

[0037] -Hole Block Layer 5- The hole-blocking layer 5 is provided to suppress the dark current generated when a bias voltage is applied between two electrodes and holes are injected from one electrode into the photoelectric conversion layer 4. Further, the hole-blocking layer 5 also has a function as an electron transport that transports electrons generated by charge separation in the photoelectric conversion layer 4 to the electrodes. The hole-blocking layer 5 can have a single layer or a plurality of layers as necessary. An N-type organic semiconductor material having electron transport properties can be used for the hole-blocking layer 5. As the N-type organic semiconductor material, any material having electron transport properties may be used. For example, polycyclic aromatic polyvalent carboxylic acid anhydrides such as naphthalene tetracarboxylic acid diimide and perylene tetracarboxylic acid diimide and their imidized products, 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, fluorenylidene methane derivatives, anthraquinodimethane and anthrone derivatives, bipyridine derivatives, quinoline derivatives, indolocarbazole derivatives, etc. can be exemplified, and one kind alone or a combination of two or more kinds selected from these N-type organic semiconductor materials can be used.

[0038] The organic optoelectronic conversion device 10 can be used in solar cells, optical sensors, imaging devices, photodetectors, LIDAR, etc.

Examples

[0039] The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. In the examples, "parts" means parts by mass, "M" means molar concentration, and "%" means mass %. The structures of the compounds described in the synthesis examples were determined by mass spectrometry (FAB-MS) and nuclear magnetic resonance spectrometry (NMR) as necessary. 11H-NMR spectra were measured using Avance400 or Avance500 (Bruker), FAB-MS spectra using JMS-700 (JEOL), and absorption spectra using UV-3600 (SHIMADZU).

[0040] [Example 1: Synthesis of Compound (1-1)] (Step 1) Synthesis of the intermediate compound represented by formula (M) Under a nitrogen atmosphere, a mixed solution of DMF (150 mL) and ethanol (4 mL) was mixed with diiodine BTBT (2.36 parts, 4.80 mmol) represented by formula (A), synthesized by the method described in Japanese Patent Publication No. 4945757, 3-thiopheneboronic acid (0.676 parts, 5.28 mmol), and tripotassium phosphate (2.04 parts, 9.60 mmol), and the mixture was stirred. Tetrakistriphenylphosphine palladium (0.277 parts, 0.240 mmol) was then added, and the reaction mixture was heated and stirred at 90°C. After 3 hours, the reaction mixture was cooled to room temperature, and the precipitated solid was collected by suction filtration. The solid was washed with water and acetone, and then recrystallized with toluene to obtain an intermediate compound represented by formula (M) (yield 1.18 parts, 55%) as a yellow solid. The mass spectrometry results of the compound represented by formula (M) are as follows. FAB-MS: m / z = 449 [M + H] +

[0041] (Step 2) Synthesis of compound (1-1) Under a nitrogen atmosphere, a mixed solution of DMF (75 mL) and ethanol (1.5 mL) was mixed with 1,4-benzenediboronic acid bis(pinacol) (0.309 parts, 0.936 mmol), the intermediate compound represented by formula (M) obtained in step 1 (1.05 parts, 2.34 mmol), and tripotassium phosphate (0.744 parts, 3.51 mmol), and the mixture was stirred. Tetrakis(triphenylphosphine)palladium (0.108 parts, 0.0936 mmol) was then added, and the reaction mixture was heated to 90°C and stirred for 5 hours. After the reaction was complete, the reaction mixture was cooled to room temperature, water was added, and the precipitated solid was collected by suction filtration. The obtained solid was washed with water and acetone and dried in a dryer. Further purification of the obtained solid by vacuum sublimation yielded compound (1-1) (0.517 parts, yield 77%) as a yellow crystalline solid.

[0042] [ka]

[0043] [Comparative Examples 1-3 (Synthesis of Comparative Compounds (4-1)-(4-3)] Comparative compounds (4-1) to (4-3) were synthesized using known methods. Comparative compounds (4-1) and (4-2) were synthesized according to the synthesis method described in Non-Patent Document 1 (Chem.Eur.J.2018,24,16595-16602). Comparative compound (4-3) was synthesized according to the synthesis method described in Patent Document 4 (US Patent Application Publication No. 2016 / 0043329).

[0044] [ka]

[0045] [Example 2: Fabrication of Photoelectric Conversion Element A] On a glass substrate on which electrodes made of ITO with a film thickness of 70 nm are formed, a block layer is formed at a substrate temperature of room temperature and a vacuum of 4.0 × 10⁻⁶. -5A 10 nm thick CzBDF (manufactured by Tokyo Chemical Industry Co., Ltd.) film was deposited under Pa conditions. Next, as a photoelectric conversion layer, the compound (1-1) obtained in Example 1, Cl6-SubPc-OPh (manufactured by Lumitec), and fullerene (C60, manufactured by Tokyo Chemical Industry Co., Ltd.) were co-deposited at a deposition rate ratio of 4:4:2 to form a 230 nm thick organic thin film. Subsequently, a 10 nm thick dpy-NDI (manufactured by Tokyo Chemical Industry Co., Ltd.), which is generally available, was deposited to form a hole block layer. Finally, an aluminum film 100 nm thick was deposited as an electrode to fabricate a photoelectric conversion element.

[0046] [ka]

[0047] [Comparative Examples 4-6: Fabrication of comparative photoelectric conversion elements P-R] Photoelectric conversion elements P to R were fabricated using the same procedure as in Example 2, except that comparative compounds (4-1), (4-2), and (4-3) were used instead of compound (1-1).

[0048] (Evaluation of organic photoelectric conversion elements) Based on the examples in International Publication No. 2018 / 105269, the photoelectric conversion elements were evaluated. Specifically, 2.0 × 10⁻¹⁰ units were applied to photoelectric conversion element A and each of elements P to R. 5 A voltage was applied to achieve an intensity of V / cm, and the EQE and dark current of the photoelectric conversion at 550 nm were measured. The results are shown in Table 2. • Evaluation criteria If EQE is 85% or higher; "A" If the percentage is between 80% and 85%, the rating is "B". If less than 80%; "C" Dark current 5.0×10 -11 A / cm 2 If less than: "A" 5.0×10 -11 The above 1.0 × 10 -10 A / cm 2 If less than: "B" 1.0 × 10 -10 A / cm 2In the above cases; "C" In practical terms, a larger EQE indicates that the irradiated light is converted into electrical energy more efficiently, meaning that "A" is superior and "C" is inferior. Similarly, a smaller dark current indicates that the current value is suppressed when the light irradiation is turned off, meaning that "A" is superior and "C" is inferior.

[0049] [Table 2]

[0050] (Evaluation of response speed) Responsiveness evaluation was performed based on the examples in International Publication No. 2018 / 105269. Specifically, 2.0 × 10⁻¹⁶ of the obtained photoelectric conversion elements were used. 5 A voltage was applied to achieve an intensity of V / cm. Then, the LED (light-emitting diode) was momentarily lit, and light was shone from the lower electrode, which is the transparent conductive film (ITO) side. The photocurrent at that time was measured with an oscilloscope, and the rise time from 0 to 97% signal intensity was measured. The relative value was then calculated with the rise time of the element in Comparative Example 4 set to 1. The results are shown in Table 3. • Evaluation criteria The relative rise time is as follows: If less than 0.1; "AA" If the value is between 0.1 and less than 0.2: "A" If the value is between 0.2 and less than 0.4: "B" If the value is between 0.4 and less than 0.6: "C" If the value is 0.6 or higher, the value is "D". In practical terms, it is desirable for the photoelectric conversion element to have a fast photoresponse speed, that is, for the photocurrent value to approach 100% in a short time after irradiation with light. Therefore, "AA" is the best and "D" is the worst.

[0051] [Table 3]

[0052] The results in Tables 2 and 3 show that the photoelectric conversion element of Example 2 exhibited good EQE and dark current values, as well as excellent response speed. In particular, the dark current and response speed were generally better compared to the comparative examples. On the other hand, the photoelectric conversion elements of Comparative Examples 4 to 6 were inferior in at least dark current and response speed among EQE, dark current values, and response speed. [Industrial applicability]

[0053] By using the condensed polycyclic aromatic compound represented by formula (1), it is possible to provide organic semiconductor devices (photoelectric conversion elements, optical sensors, etc.) with excellent EQE, dark current, and responsiveness. [Explanation of Symbols]

[0054] 1 circuit board 2. First electrode 3. Electron Block Layer 4. Photoelectric conversion layer 5 Hole block layer 6. Second electrode 10 Organic photoelectric element

Claims

1. A condensed polycyclic aromatic compound represented by the following formula (1). 【Chemistry 1】 (In formula (1), X is a divalent linking group obtained by removing two hydrogen atoms from benzene, biphenyl, or naphthalene.)

2. The condensed polycyclic aromatic compound according to claim 1, wherein X in formula (1) is selected from the group represented by the following formula (2) and the group represented by the following formula (3). 【Chemistry 2】 (In equation (2), n represents either 1 or 2.)

3. The condensed polycyclic aromatic compound according to claim 2, wherein n is 1 in formula (2).

4. An organic semiconductor material containing a condensed polycyclic aromatic compound according to any one of claims 1 to 3.

5. A material for a photoelectric device containing a condensed polycyclic aromatic compound according to any one of claims 1 to 3.

6. An organic thin film comprising a condensed polycyclic aromatic compound according to any one of claims 1 to 3, or a material for a photoelectric conversion element according to claim 5.

7. An organic photoelectric element having an organic thin film as described in claim 6.

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