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

Abstract

The objective is to provide a condensed polycyclic aromatic compound that serves as an organic photoelectric conversion material with excellent external quantum yield (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. [Solution] The following formula (1) provides a condensed polycyclic aromatic compound. [Formula 1] TIFF2026071189000011.tif21170

Description

[Technical Field]

[0001] This invention relates to novel condensed polycyclic aromatic compounds and their applications. More specifically, this invention relates to condensed polycyclic aromatic compounds that are derivatives of benzothieno[3,2-b][1]benzothiophene (hereinafter abbreviated as "BTBT"), as well as materials for photoelectric devices, organic thin films, and organic photoelectric devices 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 irradiated light can be 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 meet these required characteristics, organic photoelectric conversion elements are currently being researched to utilize a bulk heterojunction structure with a mixed film of P-type and N-type organic semiconductors for the photoelectric conversion layer, with efforts underway to achieve both improved EQE and suppressed dark current. In this research and development, the use of BTBT compounds, known for their high hole mobility, as the P-type organic semiconductor is being considered (Patent Document 3). [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] WO2022 / 114065 [Patent Document 2] Patent No. 6674547 [Patent Document 3] WO2016 / 185858 [Patent Document 4] WO2018 / 016465 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] However, few photoelectric conversion elements using BTBT compounds reported to date can simultaneously satisfy both EQE and dark current, and furthermore, none have achieved a response speed sufficient for practical use. Patent Document 4 reports a BTBT compound that exhibits excellent EQE and dark current when used in a photoelectric conversion element, but it does not describe the responsiveness.

[0007] As mentioned above, BTBT compounds exhibit high carrier mobility characteristics, thus satisfying many EQE (Equivalent Energy Exposure) requirements. However, suppressing dark current and improving responsiveness remained challenging. One cause of dark current is believed to be the unintended generation of charge due to thermal excitation from the HOMO (Highest Occupied Molecular Orbital) level of the P-type organic semiconductor to the LUMO (Lowest Unoccupied Molecular Orbital) level of the N-type organic semiconductor at the organic semiconductor-PN interface. This generation of dark current due to thermal excitation is more likely to occur when the energy difference between the HOMO level of the P-type semiconductor and the LUMO level of the N-type semiconductor is small. Conversely, a larger energy difference can prevent the generation of unwanted carriers and suppress dark current. Therefore, to suppress dark current, materials with a low HOMO energy level of the P-type organic semiconductor are preferable. However, excessively low HOMO energy levels are undesirable because they lead to a decrease in the efficiency of light-to-electrical energy conversion.

[0008] 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 external quantum yield (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]

[0009] As a result of diligent research, the inventors discovered that certain novel condensed polycyclic aromatic compounds have low HOMO energy levels, and that applying them as organic semiconductor materials solves the above-mentioned problems, thus completing the present invention.

[0010] In other words, the present invention relates to the following [1] to [4]. [1] A condensed polycyclic aromatic compound represented by the following formula (1). [ka] [2] A material for a photoelectric device containing the condensed polycyclic aromatic compound described in [1] above. [3] An organic thin film containing the condensed polycyclic aromatic compound described in [1] above, or the material for a photoelectric conversion element described in [2] above. [4] Relates to an organic photoelectric conversion element having the organic thin film described in [3] above.

Effects of the Invention

[0011] The present invention provides a condensed polycyclic aromatic compound that becomes an excellent organic photoelectric conversion material with respect to external quantum efficiency (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.

Brief Description of the Drawings

[0012] [Figure 1] It is a schematic cross-sectional view showing one embodiment of an organic photoelectric conversion element.

Modes for Carrying Out the Invention

[0013] [Condensed Polycyclic Aromatic Compound] The condensed polycyclic aromatic compound of the present invention is represented by the following formula (1).

Chemical Formula

[0014] The synthesis method of the condensed polycyclic aromatic compound of the present invention will be described. The condensed polycyclic aromatic compound represented by formula (1) can be synthesized using the following formula (S)-represented dihalogenated BTBT (2,7-dihalogenobenzene [b] benzo [4,5] thieno [2,3-b] thiophene) synthesized by a known method. It can be synthesized by subjecting a boronic acid derivative represented by the following formula (T) representing a divalent linking group to a coupling reaction using 2 equivalents (Reaction Scheme A).

[0015]

Chemical Formula

[0016] In formula (S), Z represents bromine or iodine, and in formula (T), R represents hydrogen or an alkyl group.

[0017] 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.

[0018] [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 that it contains only the compound represented by formula (1). The content of the compound represented by formula (1) in the material for photoelectric conversion elements 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. Furthermore, the material for the photoelectric conversion element may contain one or more condensed polycyclic aromatic compounds represented by formula (1). A photoelectric conversion material containing a condensed polycyclic aromatic compound represented by formula (1) can be used as a hole transport material in a photoelectric conversion element to realize a photoelectric conversion element with excellent response speed.

[0019] [Organic thin film] The organic thin film is characterized by containing the above-mentioned material for photoelectric conversion elements. 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 material for photoelectric conversion elements as is) and various solution processes (methods that use solutions in which the material for photoelectric conversion elements is dissolved and / or dispersed in an organic solvent, etc.). Examples of solution processes include spin coating, drop casting, dip coating, spraying, relief printing methods such as flexographic printing and resin relief printing, planar 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 ringgraph printing, inkjet printing, microcontact printing, and methods that combine multiple of these methods. When forming a film using a solution process, it is preferable to evaporate the solvent after coating or printing as described above to form the thin film.

[0020] [Organic photoelectric conversion element] An organic photoelectric element is a device composed of an organic semiconductor material and electrodes, etc., 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 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 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.

[0021] -substrate- 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.

[0022] -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. Multiple of these materials may be used in combination as needed, and two or more layers may be laminated.

[0023] -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.

[0024] The electron blocking layer 3 may include a P-type organic semiconductor material that is a hole-transporting material. The P-type organic semiconductor material can be any material that has hole-transporting properties, and it is preferable that the P-type organic semiconductor material is a photoelectric conversion element material containing a condensed polycyclic aromatic compound represented by formula (1) above, but other P-type organic semiconductor materials may also be used.

[0025] Other P-type organic semiconductor materials that can be used include, for example, 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, and carbazole derivatives; aromatic amine derivatives, styrylamine derivatives, benzidine derivatives, porphyrin derivatives, phthalocyanine derivatives, and quinacridone derivatives.

[0026] -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. In addition, 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, and N-type organic semiconductor materials contained in the photoelectric conversion layer 4 be dye materials that have the function of absorbing light of a desired wavelength in the visible region.

[0027] 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; 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, and indolocarbazole derivatives; aromatic amine derivatives, styrylamine derivatives, benzidine derivatives, porphyrin derivatives, phthalocyanine derivatives, and quinacridone 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, etc., can be used.

[0028] 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, two or more of the above-mentioned photoelectric device materials may be used. 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, and 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, poly-paraphenylene derivatives, polyfluorene derivatives, polyvinylcarbazole derivatives, and polythiophene derivatives. The polymer-type P-type organic semiconductor material may be mixed with the photoelectric conversion element material or non-polymer-type P-type organic semiconductor material of the present invention, or a combination of two or more polymer-type P-type organic semiconductor materials may be used.

[0029] The N-type organic semiconductor material can be any material that has electron transport properties. Examples include naphthalenetetracarboxylic acid diimide, perylenetetracarboxylic acid diimide, fullerenes, imidazole, thiazole, thiadiazole, oxazole, oxadiazole, triazole, and other azole derivatives. One or more of these N-type organic semiconductor materials can be used individually or in combination.

[0030] -Hole Block Layer 5- The hole blocking layer 5 is provided to suppress dark current generated when a bias voltage is applied between the two electrodes, causing holes to be injected into the photoelectric conversion layer 4 from one of the electrodes. The hole blocking layer 5 also functions as an electron transporter, transporting electrons generated by charge separation in the photoelectric conversion layer 4 to the electrodes. The hole blocking layer 5 can consist of a single layer or multiple layers as needed. An N-type organic semiconductor with electron transport properties can be used for the hole blocking layer 5. Examples of N-type organic semiconductor materials include any material having electron transport properties, such as polycyclic aromatic polycarboxylic acid anhydrides and their imides, like naphthalenetetracarboxylic acid diimide and perylenetetracarboxylic acid diimide, fullerenes such as C60 and C70, azole derivatives such as imidazole, thiazole, thiadiazole, oxazole, oxadiazole, and triazole, tris(8-quinolinolate)aluminum(III) derivatives, phosphine oxide derivatives, nitro-substituted fluorene derivatives, diphenylquinone derivatives, thiopyrandioxide 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 can be used individually or in combination.

[0031] The organic photoelectric conversion element 10 can be used in solar cells, light sensors, image sensors, photocounters, and LIDARs, etc. [Examples]

[0032] 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, "M" means molar concentration, and "%" means mass percent. The structures of the compounds described in the synthesis examples were determined by mass spectrometry (MALDI-MS) and nuclear magnetic resonance (NMR) spectroscopy, as needed. 1 The H-NMR spectra were measured using JNM-ECS-400 (JEOL), the MALDI-MS spectra using autoflex maX (Bruker), and the absorption spectra using UV-3600 (SHIMADZU).

[0033] [Example 1: Synthesis of Compound (1)] (Step 1-1) Synthesis of the intermediate compound represented by formula (M1-1) Under a nitrogen atmosphere, a mixture of toluene (215 mL), tetrahydrofuran (215 mL), and water (107 mL) was mixed with 4-bromo-4'-iodobenzene (23.7 parts, 83.8 mmol), 3-thiopheneboronic acid (11.8 parts, 92.2 mmol), and potassium carbonate (57.8 parts, 419 mmol) and stirred. Tetrakistriphenylphosphine palladium (3.40 parts, 2.94 mmol) was then added, the reaction mixture was heated, and stirred under reflux. After 6 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 ethanol and dried in a dryer to obtain the compound represented by formula (M1-1) (yield 17.2 parts, yield 86%) as a white solid. The mass spectrometry results of the compound represented by formula (M1-1) are as follows. MALDI-MS: m / z = 239[M+H] +

[0034] (Step 1-2) Synthesis of the intermediate compound represented by formula (M1-2) Under a nitrogen atmosphere, 16.7 parts (70.0 mmol) of the compound represented by formula (M1-1) obtained in step 1-1, 21.4 parts (84.0 mmol) of bis(pinacolate)diboron, and 16.5 parts (168 mmol) of potassium acetate were added to a 350 mL solution of 1,4-dioxane and stirred. Then, 2.86 parts (3.50 mmol) of [1,1'-bis(diphenylphosphino)ferrocene]dichloropalladium(II) was added and the reaction mixture was heated to 100°C. After 8 hours, the reaction mixture was cooled to room temperature, water and toluene were added, and the mixture was separated and extracted with toluene. Anhydrous magnesium sulfate was added to the resulting organic layer and dried. After filtration, the organic solvent was removed by distillation under reduced pressure. The resulting residue was purified by silica gel column chromatography (solvent: toluene) to obtain the compound represented by formula (M1-2) (yield 14.6 parts, yield 73%) as a white solid. The mass spectrometry results for the compound represented by formula (M1-2) were as follows: MALDI-MS: m / z = 287[M+H] +

[0035] (Steps 1-3) Synthesis of compound (1) Under a nitrogen atmosphere, 200 parts of DMF were mixed with 1.80 parts (3.68 mmol) of diiodine BTBT synthesized by the method described in Japanese Patent Publication No. 4945757, 2.53 parts (8.84 mmol) of the compound represented by formula (M1-2) obtained in step 1-2, and 2.73 parts (12.9 mmol) of tripotassium phosphate, and the mixture was stirred. Tetrakis(triphenylphosphine)palladium (0.213 parts, 0.184 mmol) was added, and the reaction mixture was heated to 90°C and stirred for 3 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) (1.23 parts, yield 60%) as a yellow crystalline solid.

[0036] [ka]

[0037] [Comparative Examples 1-3: Synthesis of Comparative Compounds (2-1)-(2-3)] Comparative compounds (2-1) to (2-3) were synthesized using known methods.

[0038] [ka]

[0039] (Measurement of HOMO level energy of organic thin films) Compound (1) obtained in Example 1, and comparative compounds (2-1) to (2-3), were resistively heated and vacuum deposited onto a pre-cleaned glass substrate to produce organic thin films (thickness 100 nm) of each compound. The HOMO level energy of each obtained organic thin film was determined by photoelectron spectroscopy (AC-3, RIKEN Keiki Co., Ltd.). The HOMO level energies of the organic thin films of each compound are shown in Table 1.

[0040] Table 1 HOMO level energy of organic thin films [Table 1]

[0041] These results indicate that compound (1) of the present invention has a moderately lower HOMO level energy than comparative compounds (2-1) and (2-3), and is significantly effective in suppressing dark current and improving response speed when used in a photoelectric conversion element. Below, we actually fabricated a photoelectric conversion element and investigated its performance.

[0042] [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. -5 A 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) of the present invention 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 photoelectric conversion element A.

[0043] [ka]

[0044] [Comparative Examples 4-6: Fabrication of Photoelectric Conversion Elements B-D] Comparative photoelectric conversion elements B to D were fabricated using the same procedure as in Example 2, except that comparative compounds (2-1), (2-2), and (2-3) were used instead of the compound represented by compound (1).

[0045] (Evaluation of photoelectric conversion elements) Based on the examples of International Publication No. 2018 / 105269, the evaluation of the photoelectric conversion element was carried out. Specifically, for each of the photoelectric conversion element A fabricated in Example 2 and the photoelectric conversion elements B to D fabricated in Comparative Examples 4 to 6, a voltage was applied so as to obtain an intensity of 2.0×10 5 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 When EQE is 90% or more; "A" When it is 80 or more and less than 90%; "B" When it is less than 80%; "C" Dark current 3.0×10 -11 A / cm 2 When less than; "A" 3.0×10 -11 When it is 1.0×10 -10 A / cm 2 When less than; "B" 1.0×10 -10 A / cm 2 When it is 1.0×10 In practical use, the larger the EQE, the more efficiently the irradiated light can be converted into electrical energy, which means that "A" is excellent and "C" is inferior. The smaller the dark current, the more the current value when the light irradiation is OFF can be suppressed, which means that "A" is excellent and "C" is inferior.

[0046] Table 2 Evaluation results of the photoelectric conversion element

Table 2

[0047] (Evaluation of response speed) Based on the examples of International Publication No. 2018 / 105269, the evaluation of the responsiveness was carried out. Specifically, a voltage was applied to the obtained photoelectric conversion element so as to obtain an intensity of 2.0×1( 5 V / cm. Then, an LED (light emitting diode) was instantaneously lit to irradiate light from the lower electrode on the transparent conductive film (ITO) side, and the photocurrent at that time was measured with an oscilloscope to measure the rise time from 0 to 97% of the signal intensity. • Evaluation criteria If less than 5ms; "A" If the ms is between 5 and 10ms, the value is "B". If 10ms or longer; "C" In practical terms, it is preferable for the photoelectric conversion element to have a fast photoresponse speed, that is, for the photocurrent to approach 100% in a short time after irradiation with light. Therefore, "A" is superior and "C" is inferior.

[0048] Table 3 Evaluation results of photoelectric conversion elements [Table 3]

[0049] The results in Tables 2 and 3 clearly show that the photoelectric conversion element using the compound represented by equation (1) exhibits sufficient EQE and dark current values, as well as excellent response speed. [Industrial applicability]

[0050] By using the compound represented by formula (1) of the present invention, it is possible to supply organic semiconductor devices (photoelectric conversion elements, optical sensors, etc.) with excellent responsiveness. [Explanation of Symbols]

[0051] 1 circuit board 2. First electrode 3. Electron Block Layer 4 Photoelectric conversion elementary 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】

2. A material for a photoelectric device containing the condensed polycyclic aromatic compound described in claim 1.

3. An organic thin film comprising the condensed polycyclic aromatic compound described in claim 1 or the material for a photoelectric conversion element described in claim 2.

4. An organic photoelectric element having an organic thin film as described in claim 3.

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