JP2023122010A - Fused polycyclic aromatic compound - Google Patents

Abstract

To provide a material for a photoelectric conversion element for an image sensor, and an organic photoelectric conversion element using the photoelectric conversion materia l that efficiently absorbing light in a blue light region around 450 nm, and has an excellent material that can exhibit a large bright-to-dark current ratio.SOLUTION: A fused polycyclic aromatic compound is represented by the following formula (in the formula (1), X each independently represents an oxygen atom, sulfur atom, or selenium atom, and R1 to R12 each independently represent a hydrogen atom or a residue obtained by removing one hydrogen atom from an aromatic compound).SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to novel condensed polycyclic aromatic compounds and uses thereof. More particularly, the present invention relates to a condensed polycyclic aromatic compound which is an anthracene derivative, an organic thin film containing the compound, and an organic photoelectric conversion device having the organic thin film.

In recent years, organic thin film devices such as field effect transistors and organic photoelectric conversion elements have attracted attention, and various organic electronic materials represented by condensed polycyclic aromatic compounds used in these thin film devices have been researched and developed. .
For example, Patent Document 1 discloses a photoelectric conversion element having an N-type organic semiconductor as a photoelectric conversion layer, but the dark current could not be sufficiently reduced.

In response to this problem, Patent Document 2 discloses a photoelectric conversion element in which dark current is reduced by using an organic photoelectric conversion material having a specific structure. However, this photoelectric conversion element has an electron-blocking layer and a hole-blocking layer as constituent elements of the element, and there is a problem that the dark current cannot be sufficiently reduced with only a single photoelectric conversion layer.

Patent Document 3 discloses that thin films of anthracene derivatives have organic semiconductor properties. Patent Literature 4 discusses application of an anthracene derivative to a P-type organic semiconductor of an organic photoelectric conversion element.

However, the anthracene derivative that constitutes the organic photoelectric conversion layer of Patent Document 4 has transparency to visible light, and the organic dye that selectively absorbs green light around 560 nm functions as a photoelectric conversion material. there is Therefore, there is a problem as an organic semiconductor material that has high photoelectric conversion characteristics in the blue light region and provides a sufficient light-dark current ratio.

Japanese Patent No. 5520560 JP 2017-174921 A U.S. Pat. No. 7,781,761 WO2019/150988

The present invention has been made in view of the above-described conventional problems, and provides a material for organic photoelectric conversion elements that is excellent in photoelectric conversion characteristics in the blue light region and provides a sufficient light-to-dark current ratio, and the material for organic photoelectric conversion elements. It is an object of the present invention to provide an organic thin film containing the organic thin film and an organic semiconductor device (a photoelectric conversion element having a large light-to-dark current ratio in the blue light region) having the organic thin film.

As a result of intensive studies, the present inventors have found that the above problems can be solved by using a novel condensed polycyclic aromatic compound having a specific structure, and have completed the present invention.
That is, the present invention
[1] General formula (1)

(In the formula (1), each X independently represents an oxygen atom, a sulfur atom or a selenium atom, and each of R ₁ to R ₁₂ independently represents a hydrogen atom or a residue obtained by removing one hydrogen atom from an aromatic compound. .)
A condensed polycyclic aromatic compound represented by
[2] The condensed polycyclic aromatic compound according to [1] above, wherein each X is independently an oxygen atom or a sulfur atom;
[3] The condensed polycyclic aromatic compound according to [1] or [2] above, wherein each of R ₁ to R ₁₂ is independently a hydrogen atom or a residue obtained by removing one hydrogen atom from an aromatic hydrocarbon compound;
[4] The condensed polycyclic aromatic compound according to any one of [1] to [3] above, wherein R ₃ to R ₆ and R ₉ to R ₁₂ are hydrogen atoms;
[5] The condensed polycyclic aromatic compound according to [4] above, wherein R ₂ and R ₈ are hydrogen atoms;
[6] The condensed polycyclic aromatic compound according to [5] above, wherein R ₁ and R ₇ are each independently a hydrogen atom, a phenyl group, a biphenyl group or a naphthyl group;
[7] The condensed polycyclic aromatic compound according to [6] above, wherein R ₁ and R ₇ are the same;
[8] A material for an organic photoelectric conversion device containing the condensed polycyclic aromatic compound according to any one of [1] to [7] above,
[9] An organic thin film containing the condensed polycyclic aromatic compound according to any one of [1] to [7] above,
[10] An organic photoelectric conversion element having the organic thin film according to [9] above, and [11] An organic photoelectric conversion element having a photoelectric conversion layer comprising the organic thin film according to [9] above,
Regarding.

The organic photoelectric conversion device using the condensed polycyclic aromatic compound represented by the formula (1) of the present invention has an absorption band in the blue light region around 450 nm and exhibits a large light-dark current ratio. It can be used for organic photoelectric conversion elements and organic image pickup elements, materials thereof, and the like.

FIG. 1 shows a cross-sectional view illustrating an embodiment of the organic photoelectric conversion element of the present invention.

The contents of the present invention will be described in detail below. While the descriptions of the constituent elements described herein are based on representative embodiments and examples of the present invention, the present invention is not limited to such embodiments and examples.

The condensed polycyclic aromatic compound of the present invention is represented by the general formula (1).
In formula (1), each X independently represents an oxygen atom, a sulfur atom or a selenium atom, and each of R ₁ to R ₁₂ independently represents a hydrogen atom or a residue obtained by removing one hydrogen atom from an aromatic compound.

Aromatic compounds that can be the residues represented by R ₁ to R ₁₂ in formula (1) are not particularly limited as long as they are aromatic compounds, and examples include benzene, biphenyl, naphthalene, triphenyl, anthracene, phenanthrene, Chrysene, pyrene, triphenylene, fluorene, pyridine, thiophene, furan, benzothiophene, benzofuran, dibenzothiophene, dibenzofuran, thienothiophene, naphthofuran and naphthothiophene.

The residue obtained by removing a hydrogen atom from the aromatic compound represented by R ₁ to R ₁₂ in formula (1) is preferably a residue obtained by removing one hydrogen atom from an aromatic hydrocarbon compound, such as benzene, biphenyl, naphthalene, A residue obtained by removing one hydrogen atom from triphenyl, anthracene or phenanthrene is more preferred, and a residue obtained by removing one hydrogen atom from benzene, biphenyl or naphthalene is even more preferred.

Each X in formula (1) is preferably an oxygen atom or a sulfur atom independently, and more preferably two Xs in formula (1) are the same oxygen atom or sulfur atom.

R ₁ to R ₁₂ in formula (1) are preferably each independently a hydrogen atom or a residue obtained by removing one hydrogen atom from an aromatic hydrocarbon compound, and R ₁ , R ₂ , R ₇ and R ₈ are each independently a hydrogen atom or a residue obtained by removing one hydrogen atom from an aromatic hydrocarbon compound, and more preferably, R ₃ to R ₆ and R ₉ to R ₁₂ are hydrogen atoms, and R ₁ and R ₇ are each independently a hydrogen atom or a residue obtained by removing one hydrogen atom from an aromatic hydrocarbon compound, and R ₂ to R ₆ and R ₈ to R ₁₂ are more preferably hydrogen atoms, It is particularly preferred that R ₁ and R ₇ are each independently a hydrogen atom, a phenyl group, a biphenyl group or a naphthyl group, and R ₂ to R ₆ and R ₈ to R ₁₂ are hydrogen atoms, and R ₁ and R ₇ are Most preferably, _R2 to _R6 and _R8 to _R12 are the same hydrogen atom, phenyl group, biphenyl group or naphthyl group and are hydrogen atoms.

As the condensed polycyclic aromatic compound represented by the formula (1) of the present invention, a combination of the preferred X and the preferred R ₁ to R ₁₂ described above is more preferred.

Next, a method for synthesizing the condensed polycyclic aromatic compound represented by the general formula (1) of the present invention will be described in detail. The condensed polycyclic aromatic compound represented by the general formula (1) can be synthesized by various conventionally known methods, and the synthesis method of the following scheme will be described as an example.

Compounds represented by formula (1) are disclosed in Patent Document 3 and ACS Appl. Energy Mater. 2020, 3(11), 10752, and the like. For example, a synthetic method according to the following scheme can be mentioned. Using 2,6-diaminoanthraquinone (A) as a raw material, 2,6-dibromoanthraquinone (B) is formed by Sandmeyer reaction, and 2,6-dibromoanthracene (C) is obtained by reducing this. (Although a bromide is described as an example of the halide (B) in the scheme below, it is not limited thereto).
The compound represented by formula (1) can also be synthesized by the known method disclosed in J.Am.Chem.Soc., 2017, 139(48), 17261. As a starting material, 2,6-dihydroxyanthraquinone (D) is reduced to form 2,6-dihydroxyanthracene (E), which is trifluoromethylsulfonylated to give trifluoromethylsulfonylate (F). .
Next, using the compound (C) or (F) obtained above and the compound (G) or (G') as starting materials, the condensed polycyclic aromatic compound of the present invention represented by the general formula (1) is synthesized. do. Here, the reaction between compound (C) or (F) and compound (G) is performed by a known method according to the Suzuki-Miyaura coupling reaction, and compound (C) or (F) and compound (G') The reaction may be carried out by a known method according to the Migita-Kosugi-Still cross-coupling reaction. Edition" etc. can be referred to.

In the above coupling reaction, it is preferable to use 2 to 10 mol, more preferably 2 to 4 mol, of compound (G) or (G') per 1 mol of compound (C) or (F). .
The reaction temperature of the above coupling reaction is usually -10 to 200°C, preferably 20 to 160°C, more preferably 30 to 120°C. Also, the reaction time is not particularly limited, but is usually 1 to 72 hours, preferably 2 to 48 hours. Depending on the type of catalyst described later, the reaction temperature can be lowered and the reaction time can be shortened.
The above coupling reaction is preferably carried out under an inert gas atmosphere such as an argon atmosphere, nitrogen substitution, dry argon atmosphere, or dry nitrogen stream.

A catalyst is preferably used for the coupling reaction using the compound (G). Examples of catalysts that can be used in the coupling reaction include tri-tert-butylphosphine, triadamantylphosphine, 1,3-bis(2,4,6-trimethylphenyl)imidazolidinium chloride, 1,3-bis(2 ,6-diisopropylphenyl)imidazolidinium chloride, 1,3-diadamantylimidazolidinium chloride, or mixtures thereof; metal Pd, Pd/C (hydrous or non-hydrous), palladium acetate, palladium trifluoroacetate, methanesulfone palladium acid, palladium toluenesulfonate, palladium chloride, palladium bromide, palladium iodide, bis(acetonitrile)palladium(II) dichloride, bis(benzonitrile)palladium(II) dichloride, tetrakis(acetonitrile)palladium(II) tetrafluoroborate ), tris(dibenzylideneacetone)dipalladium(0), tris(dibenzylideneacetone)dipalladium(0) chloroform complex and bis(dibenzylideneacetone)palladium(0), bis(triphenylphosphino)palladium dichloride (Pd (PPh ₃ ) ₂ Cl ₂ ), (1,1′-bis(diphenylphosphino)ferrocene)palladium dichloride (Pd(dppf)Cl ₂ ), tetrakis(triphenylphosphine)palladium (Pd(PPh ₃ ) ₄ ), etc. but palladium-based catalysts are preferred. Pd(dppf)Cl ₂ , Pd(PPh ₃ ) ₂ Cl ₂ and Pd(PPh ₃ ) ₄ are more preferred, and Pd(PPh ₃ ) ₂ Cl ₂ and Pd(PPh ₃ ) ₄ are even more preferred.
A plurality of these catalysts may be used in combination, or these catalysts may be used in combination with other catalysts.
The amount of these catalysts used in the coupling reaction is preferably 0.001 to 0.500 mol, more preferably 0.001 to 0.100 mol, still more preferably 1 mol of compound (F). 0.001 to 0.060 mol.

A basic compound is preferably used for the coupling reaction using compound (G). Basic compounds include, for example, hydroxides such as lithium hydroxide, barium hydroxide, sodium hydroxide and potassium hydroxide, lithium carbonate, lithium hydrogen carbonate, sodium carbonate, sodium hydrogen carbonate, potassium carbonate, potassium hydrogen carbonate and carbonates such as cesium carbonate; acetates such as lithium acetate, sodium acetate and potassium acetate; phosphates such as trisodium phosphate and tripotassium phosphate; alkoxides, metal hydrides such as sodium hydride and potassium hydride; organic bases such as pyridine, picoline, lutidine, triethylamine, tributylamine, diisopropylethylamine and N,N-dicyclohexylmethylamine; or hydroxide is preferred, and trisodium phosphate, tripotassium phosphate, sodium hydroxide or potassium hydroxide is more preferred. These basic compounds may be used alone or in combination of two or more.
The amount of these basic compounds to be used in the coupling reaction is preferably 2 to 100 mol, more preferably 2 to 10 mol, per 1 mol of compound (C) or (F).

A Pd- or Ni-based catalyst is preferably used for the coupling reaction using the compound (G'). As the catalyst, any Pd-based or Ni-based catalyst can be used without particular limitation.
Examples of the Pd-based catalyst include those described in the section of the catalyst that can be used for the coupling reaction using the compound (G).
Ni-based catalysts include, for example, tetrakis(triphenylphosphine)nickel (Ni(PPh ₃ ) ₄ ), nickel(II) acetylacetonate (Ni(acac) ₂ ), dichloro(2,2′-bipyridine)nickel (Ni(bpy)Cl2), dibromobis(triphenylphosphine)nickel ( _Ni ( _PPh3 ) _2Br2 ) _, bis(diphenylphosphino)propanenickel dichloride (Ni(dppp) _Cl2 ) and bis(diphenylphosphino) ) ethane nickel dichloride (Ni(dppe)Cl ₂ ), etc., preferably Pd(dppf)Cl ₂ , Pd(PPh ₃ ) ₂ Cl ₂ , Pd(PPh ₃ ) ₄ , Pd(PPh ₃ ) ₂ Cl ₂ , Pd(PPh ₃ ) ₄ are more preferred.
A plurality of these catalysts may be used in combination, or these catalysts may be used in combination with other catalysts.
The amount of these catalysts used in the coupling reaction is preferably 0.001 to 0.500 mol, more preferably 0.001 to 0.100 mol, per 1 mol of compound (C) or (F). and more preferably 0.001 to 0.060 mol.

An alkali metal salt may be used in combination for the coupling reaction using the compound (G').
The alkali metal salt that can be used in combination is not particularly limited as long as it contains an alkali metal, and examples thereof include lithium chloride, lithium bromide and lithium iodide, with lithium chloride being preferred.
The amount of the alkali metal salt to be added is preferably 0.001 to 5.0 mol per 1 mol of compound (F).

The above coupling reaction may be carried out in a solvent. Solvents that can be used can dissolve necessary raw materials such as compound (C) or (F) and compound (G) or (G'), as well as catalysts, basic compounds, alkali metal salts, etc. used if necessary. Any solvent can be used.
Specific examples of solvents include aromatic compounds such as chlorobenzene, o-dichlorobenzene, bromobenzene, nitrobenzene, toluene and xylene, saturated aliphatic hydrocarbons such as n-hexane, n-heptane and n-pentane, Alicyclic hydrocarbons such as cyclohexane, cycloheptane and cyclopentane, n-propyl bromide, n-butyl chloride, n-butyl bromide, dichloromethane, dibromomethane, dichloropropane, dibromopropane, dichlorobutane, chloroform, bromoform, saturated aliphatic halogenated hydrocarbons such as carbon chloride, carbon tetrabromide, trichloroethane, tetrachloroethane and pentachloroethane, halogenated cyclic hydrocarbons such as chlorocyclohexane, chlorocyclopentane and bromocyclopentane, ethyl acetate, propyl acetate , butyl acetate, methyl propionate, ethyl propionate, propyl propionate, butyl propionate, esters such as methyl butyrate, ethyl butyrate, propyl butyrate and butyl butyrate, acetone, ketones such as methyl ethyl ketone and methyl isobutyl ketone, diethyl ether , dipropyl ether, dibutyl ether, cyclopentyl methyl ether, dimethoxyethane, tetrahydrofuran, 1,4-dioxane and 1,3-dioxane; N-methyl-2-pyrrolidone, N,N-dimethylformamide and N, Amides such as N-dimethylacetamide, glycols such as ethylene glycol, propylene glycol and polyethylene glycol, and sulfoxides such as dimethyl sulfoxide may be mentioned. These solvents may be used alone or in combination of two or more.

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. Moreover, these methods can be combined as needed.

In the above synthesis scheme, R ₁₃ and R ₁₄ in compound (G) each independently represent a hydrogen atom or an alkyl group, or R ₁₃ and R ₁₄ combine to form an alkylene group.
The alkyl groups represented by R ₁₃ and R ₁₄ include methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, iso-butyl, tert-butyl, n- C1-C6 alkyl groups such as pentyl group and n-hexyl group can be mentioned.
The alkylene group formed by combining R ₁₃ and R ₁₄ includes methylene group, ethane-1,2-diyl group, butane-2,3-diyl group, and 2,3-dimethylbutane-2,3-diyl group. and propane-1,3-diyl group.
As R ₁₃ and R ₁₄ in compound (G), both R ₃ and R ₄ are hydrogen atoms, or R ₃ and R ₄ are bonded to form a 2,3-dimethylbutane-2,3-diyl group is preferably formed.

In the above synthesis scheme, R ₁₅ to R ₁₇ in compound (G') each independently represent a linear or branched alkyl group. The alkyl group represented by R ₁₅ to R ₁₇ usually has 1 to 8 carbon atoms, preferably 1 to 4 carbon atoms. Specific examples of linear alkyl groups include methyl group, ethyl group, n-propyl group, n-butyl group, iso-butyl group, n-pentyl group and n-hexyl group, and specific examples of branched chain alkyl groups. Examples include iso-propyl group, iso-butyl group, sec-butyl group, tert-butyl group, iso-pentyl group and iso-hexyl group.
R ₁₅ to R ₁₇ in the compound (G′) are each independently preferably a methyl group or a butyl group, more preferably all methyl groups or all butyl groups.
R ₁ to R ₁₂ in compounds (G) and (G') have the same definitions as R ₁ to R ₁₂ in general formula (1).

Specific examples of the condensed polycyclic aromatic compound of the present invention represented by formula (1) are shown below, but the present invention is not limited to these specific examples.

The organic thin film of the present invention contains a condensed polycyclic aromatic compound represented by Formula (1). The film thickness of the organic thin film varies depending on its use, but is usually 1 nm to 1 μm, preferably 5 nm to 500 nm, more preferably 10 nm to 300 nm.

Examples of the method for forming the organic thin film in the present invention include a general dry film forming method and a wet film forming method. Specifically, vacuum processes such as resistance heating deposition, electron beam deposition, sputtering, molecular lamination, solution processes such as casting, spin coating, dip coating, blade coating, wire bar coating, spray coating, and inkjet printing. , printing methods such as screen printing, offset printing, letterpress printing, soft lithography methods such as microcontact printing methods, etc., and a method combining a plurality of these methods may be employed for forming each layer.

An organic electronic device can be produced using the condensed polycyclic aromatic compound represented by the general formula (1) or a thin film. Examples of organic electronic devices include thin film transistors, organic photoelectric conversion elements, organic solar cell elements, organic EL elements, organic light emitting transistor elements, and organic semiconductor laser elements.
Next, in the present invention, materials for organic photoelectric conversion elements and organic photoelectric conversion elements (including photosensors and organic imaging elements) will be described.

The organic photoelectric conversion device material of the present invention contains a condensed polycyclic aromatic compound represented by the above formula (1). The content of the compound represented by formula (1) in the organic photoelectric conversion element material of the present invention is not particularly limited as long as the performance required in the application using the organic photoelectric conversion element material is exhibited, but usually is 50% by mass or more, preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more.
The organic photoelectric conversion element material of the present invention contains a compound other than the compound represented by the formula (1) (for example, an organic photoelectric conversion element material other than the compound represented by the formula (1), etc.) and additives. They may be used together. Compounds, additives, and the like that can be used in combination are not particularly limited as long as the performance required in the application using the organic photoelectric conversion element material is exhibited.

The organic photoelectric conversion element of the present invention has the organic thin film of the present invention. An organic photoelectric conversion element is an element in which a photoelectric conversion portion (film) is arranged between a pair of opposing electrode films, and light is incident on the photoelectric conversion portion from above the electrode films. The photoelectric conversion portion generates electrons and holes in response to the incident light, and a semiconductor device reads out a signal corresponding to the charge and indicates the amount of incident light corresponding to the absorption wavelength of the photoelectric conversion film portion. is. A readout transistor may be connected to the electrode film on the side where light does not enter. When a large number of organic photoelectric conversion elements are arranged in an array, they serve as an imaging element because they indicate incident position information in addition to the amount of incident light. In addition, when the organic photoelectric conversion element arranged closer to the light source does not block (transmits) the absorption wavelength of the organic photoelectric conversion element arranged behind it when viewed from the light source side, a plurality of organic photoelectric conversion elements are used. You may laminate and use.

The organic photoelectric conversion element of the present invention uses an organic thin film containing the condensed polycyclic aromatic compound represented by the above formula (1) as a constituent material of the photoelectric conversion portion.
The photoelectric conversion part includes one or more selected from the group consisting of a photoelectric conversion layer, an electron transport layer, a hole transport layer, an electron blocking layer, a hole blocking layer, an anti-crystallization layer, an interlayer contact improving layer, and the like. It is often composed of an organic thin film layer other than the photoelectric conversion layer. The condensed polycyclic aromatic compound of the present invention is preferably used as an organic thin film layer of a photoelectric conversion layer, but the above organic thin film layers (especially, electron transport layer, hole transport layer, electron blocking layer, hole It can also be used as a block layer). Electron blocking layers and hole blocking layers are also referred to as carrier blocking layers. When the photoelectric conversion layer is used, it may be composed only of the condensed polycyclic aromatic compound of the present invention, but may contain an organic semiconductor material in addition to the condensed polycyclic aromatic compound of the present invention. These organic thin film layers may have a laminated structure, but may also include organic thin films formed by co-evaporation of materials, and in addition, co-evaporated films, single films, or other co-evaporated films are formed in multiple layers. , it may be an organic thin film that functions.

The electrode film used in the organic photoelectric conversion element of the present invention is used when the photoelectric conversion layer contained in the photoelectric conversion part described later has a hole-transport property, or when the organic thin film layer other than the photoelectric conversion layer has a hole-transport property. When it is a hole-transporting layer, it plays a role of extracting and collecting holes from the photoelectric conversion layer and other organic thin film layers, and the photoelectric conversion layer contained in the photoelectric conversion part has an electron-transporting property. In some cases, or when the organic thin film layer is an electron transport layer having electron transport properties, it plays a role of extracting electrons from the photoelectric conversion layer or other organic thin film layers and ejecting them. Therefore, the material that can be used as the electrode film is not particularly limited as long as it has a certain degree of conductivity. is preferably selected in consideration of Examples of materials that can be used as electrode films include conductive metal oxides such as tin oxide (NESA), indium oxide, indium tin oxide (ITO), and indium zinc oxide (IZO); gold, silver, platinum, chromium, and aluminum. , metals such as iron, cobalt, nickel and tungsten; inorganic conductive substances such as copper iodide and copper sulfide; conductive polymers such as polythiophene, polypyrrole and polyaniline; and carbon. A plurality of these materials may be mixed and used if necessary, or a plurality of these materials may be used by laminating two or more layers. The conductivity of the material used for the electrode film is also not particularly limited as long as it does not interfere with the light reception of the organic photoelectric conversion element more than necessary. For example, a conductive ITO film with a sheet resistance value of 300 Ω/□ or less functions well as an electrode film, but substrates with an ITO film having a conductivity of several Ω/□ are also available on the market. Therefore, it is desirable to use a substrate having such high conductivity. Although the thickness of the ITO film (electrode film) can be arbitrarily selected in consideration of conductivity, it is usually about 5 to 500 nm, preferably about 10 to 300 nm. Methods for forming a film such as ITO include conventionally known vapor deposition methods, electron beam methods, sputtering methods, chemical reaction methods, coating methods, and the like. If necessary, the ITO film provided on the substrate may be subjected to UV-ozone treatment, plasma treatment, or the like.

Materials for the transparent electrode film used for at least one of the light incident sides of the electrode film include ITO, IZO, SnO ₂ , ATO (antimony-doped tin oxide), ZnO, and AZO (Al-doped zinc oxide). , GZO (gallium-doped zinc oxide), _TiO2 and FTO (fluorine-doped tin oxide), etc. The transmittance of light incident through the transparent electrode film at the absorption peak wavelength of the photoelectric conversion layer is preferably 60% or more, more preferably 80% or more, and particularly preferably 95% or more. .

The electrode film is preferably produced plasma-free. By forming these electrode films in a plasma-free manner, the influence of plasma on the substrate on which the electrode films are provided is reduced, and the photoelectric conversion characteristics of the photoelectric conversion element can be improved. Here, "plasma-free" means that no plasma is generated during the deposition of the electrode film, or that the distance from the plasma generation source to the substrate is 2 cm or more, preferably 10 cm or more, more preferably 20 cm or more, and the plasma reaches the substrate. Denotes the state in which the plasma is reduced.

Examples of apparatuses that do not generate plasma when forming an electrode film include an electron beam vapor deposition apparatus (EB vapor deposition apparatus) and a pulse laser vapor deposition apparatus. A method of forming a transparent electrode film using an EB vapor deposition device is called an EB vapor deposition method, and a method of forming a transparent electrode film using a pulse laser vapor deposition device is called a pulse laser vapor deposition method.

As an apparatus capable of realizing a state in which plasma can be reduced during film formation, for example, a facing target type sputtering apparatus, an arc plasma vapor deposition apparatus, and the like can be considered.

When a transparent conductive film is used as an electrode film (for example, a first conductive film), a DC short circuit or an increase in leakage current may occur. One of the reasons for this is that fine cracks generated in the photoelectric conversion layer are covered with a dense film such as TCO (Transparent Conductive Oxide), and the conduction between the transparent conductive film and the electrode film on the opposite side increases. it is conceivable that. Therefore, when a material such as Al having a relatively inferior film quality is used for the electrode, an increase in leakage current is less likely to occur. By controlling the film thickness of the electrode film according to the film thickness (crack depth) of the photoelectric conversion layer, an increase in leakage current can be suppressed.

Generally, when the conductive film is made thinner than a predetermined value, a rapid increase in resistance value occurs. The sheet resistance of the conductive film in the organic photoelectric conversion element for photosensors of this embodiment is usually 100 to 10,000 Ω/□, and the degree of freedom in film thickness is large. Also, the thinner the transparent conductive film, the less light it absorbs, and generally the higher the light transmittance. When the light transmittance is high, the amount of light absorbed by the photoelectric conversion layer is increased and the photoelectric conversion performance is improved, which is very preferable.

The photoelectric conversion part of the organic photoelectric conversion element of the present invention may include a photoelectric conversion layer and an organic thin film layer other than the photoelectric conversion layer. An organic semiconductor film is generally used for the photoelectric conversion layer constituting the photoelectric conversion part, but the organic semiconductor film may be a single layer or a plurality of layers. An N-type organic semiconductor film or a mixed film thereof (bulk heterostructure) is used. On the other hand, in the case of a plurality of layers, it is about 2 to 10 layers, and it is a structure in which either a P-type organic semiconductor film, an N-type organic semiconductor film, or a mixed film thereof (bulk heterostructure) is laminated. A buffer layer may be inserted in the . The thickness of the photoelectric conversion layer is usually 50 to 500 nm.

The organic semiconductor film of the photoelectric conversion layer contains triarylamine compounds, benzidine compounds, pyrazoline compounds, styrylamine compounds, hydrazone compounds, triphenylmethane compounds, carbazole compounds, polysilane compounds, thiophene compounds, and phthalocyanine compounds, depending on the absorption wavelength band. compounds, cyanine compounds, merocyanine compounds, oxonol compounds, polyamine compounds, indole compounds, pyrrole compounds, pyrazole compounds, polyarylene compounds, carbazole derivatives, naphthalene derivatives, anthracene derivatives, chrysene derivatives, phenanthrene derivatives, pentacene derivatives, phenylbutadiene derivatives, styryl Derivatives, quinoline derivatives, tetracene derivatives, pyrene derivatives, perylene derivatives, fluoranthene derivatives, quinacridone derivatives, coumarin derivatives, porphyrin derivatives, fullerene derivatives, metal complexes (Ir complexes, Pt complexes, Eu complexes, etc.) and the like can be used. It functions as a P-type organic semiconductor or an N-type organic semiconductor depending on the combination with the condensed polycyclic aromatic compound of the present invention.

When the condensed polycyclic aromatic compound of the present invention is used as a photoelectric conversion layer, it preferably has a HOMO level shallower than the HOMO (Highest Occupied Molecular Orbital) level of the combined organic semiconductor. This makes it possible to improve the photoelectric conversion efficiency in addition to suppressing the generation of dark current.

In the organic photoelectric conversion device of the present invention, the organic thin film layer other than the photoelectric conversion layer constituting the photoelectric conversion part is a layer other than the photoelectric conversion layer, such as an electron transport layer, a hole transport layer, an electron blocking layer, and a hole blocking layer. It can also be used as a layer, an anti-crystallization layer, an interlayer contact improving layer, or the like. In particular, by using one or more thin film layers selected from the group consisting of an electron transport layer, a hole transport layer, an electron block layer and a hole block layer, an element that efficiently converts even weak light energy into electrical signals can be obtained. Therefore, it is preferable.

The electron transport layer plays a role of transporting electrons generated in the photoelectric conversion layer to the electrode film and a role of blocking the movement of holes from the electrode film to which the electrons are transported to the photoelectric conversion layer. The hole transport layer plays a role of transporting generated holes from the photoelectric conversion layer to the electrode film and a role of blocking the movement of electrons from the electrode film to which the holes are transported to the photoelectric conversion layer. The electron blocking layer plays a role of preventing movement of electrons from the electrode film to the photoelectric conversion layer, preventing recombination within the photoelectric conversion layer, and reducing dark current. The hole blocking layer has a function of preventing holes from moving from the electrode film to the photoelectric conversion layer, preventing recombination in the photoelectric conversion layer, and reducing dark current.
The hole blocking layer is formed by laminating or mixing one or more types of hole blocking substances. The hole-blocking substance is not limited as long as it is a compound capable of blocking holes from flowing out of the device from the electrode. Compounds that can be used in the hole-blocking layer include phenanthroline derivatives such as bathophenanthroline and bathocuproine, silole derivatives, quinolinol derivative metal complexes, oxadiazole derivatives, oxazole derivatives, quinoline derivatives, among others. 1 type, or 2 or more types can be used.

Although FIG. 1 shows a typical device structure of the organic photoelectric conversion device of the present invention, the present invention is not limited to this structure. In the example of FIG. 1, 1 is an insulating part, 2 is one electrode film, 3 is an electron blocking layer, 4 is a photoelectric conversion layer, 5 is a hole blocking layer, 6 is the other electrode film, and 7 is an insulating base. material or other organic photoelectric conversion element, respectively. Although no readout transistor is shown in the figure, it may be connected to two or six electrode films. may be formed outside the electrode film. Light is incident on the photoelectric conversion element from either the top or the bottom, provided that the components other than the photoelectric conversion layer 4 do not extremely block the incidence of the light of the main absorption wavelength of the photoelectric conversion layer. It's okay.

EXAMPLES 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, "part" means "mass part" unless otherwise specified, and "%" means "mass %". "M" represents molar concentration. In addition, unless otherwise specified, the reaction temperature is the internal temperature of the reaction system.
In the examples, EI-MS was measured using ISQ7000 manufactured by Thermo Scientific, and nuclear magnetic resonance (NMR) was measured using JNM-EC400 manufactured by JEOL.
Measurement of applied current and voltage of the organic photoelectric conversion element in the examples was performed using a semiconductor parameter analyzer 4200-SCS (manufactured by Keithley Instruments). Irradiation with incident light was performed using PVL-3300 (manufactured by Asahi Spectrosco Co., Ltd.) with an irradiation light half width of 20 nm. The light-dark ratio in the examples means the current obtained by dividing the current in the case of light irradiation by the current in the dark place.

Example 1 (Synthesis of Condensed Polycyclic Aromatic Compound Represented by Specific Example No. 1)
(Step 1) Specific example No. Synthesis of Condensed Polycyclic Aromatic Compound Represented by 1 In DMF (120 parts), ACS Appl. Energy Mater. 2020, 3 (11), 2,6-dibromoanthracene synthesized by the method described in 10752 (1.5 parts), 2-trimethylstannyl (naphtho[2,3-b]thiophene) (4.7 parts) , copper (I) iodide (0.09 parts) and tetrakis(triphenylphosphine)palladium (0.15 parts) were added, and the mixture was stirred at 80° C. for 4 hours under a nitrogen atmosphere. After cooling the obtained reaction liquid to room temperature, water (100 parts) was added, and solid content was fractionated by filtration. The obtained solid was washed with acetone and DMF, dried, and then purified by sublimation to give specific example No. A compound represented by 1 (1.9 parts, yield 78%) was obtained.

No. of the specific example obtained above. The results of EI-MS measurement of the compound represented by 1 were as follows.
EI-MS m/z: Calcd for _C38H22S2 [M ⁺ ]: 542.71. Found _{: 542.16}

Example 2 (Synthesis of Condensed Polycyclic Aromatic Compound Represented by Specific Example No. 2)
(Step 2) Synthesis of an intermediate compound represented by the following formula 2 To dehydrated THF (140 parts), Chemical Communications. 2012, 48 (47), Naphtho[2,3-b]furan (5.0 parts) synthesized by the method described in 5892 is added, cooled to -78 ° C. under a nitrogen atmosphere, and 1.0 M lithium diisopropylamide A THF/hexane solution (50.0 parts) of was added, and the mixture was stirred for 1 hour. Then, trimethyltin chloride (7.5 parts) was added, and the mixture was stirred for 1 hour, warmed to room temperature, and further stirred for 2 hours. The resulting reaction solution was quenched with water (100 parts), washed with an aqueous potassium fluoride solution, and then separated and extracted with ethyl acetate. The obtained organic layer was dried using sodium sulfate, and the solvent was distilled off under reduced pressure. The obtained solid was purified with a silica gel column (developing solvent: hexane) to obtain an intermediate compound represented by the following formula 2 (6.0 parts, yield 61%).

(Step 3) Specific example No. Synthesis of condensed polycyclic aromatic compound represented by 2 To toluene (120 parts), ACS Appl. Energy Mater. 2020, 3 (11), 2,6-dibromoanthracene synthesized by the method described in 10752 (1.0 parts), the intermediate compound represented by formula 2 obtained in step 2 (2.9 parts), Tetrakis(triphenylphosphine)palladium (0.10 parts) was added, and the mixture was stirred at 80° C. for 6 hours under a nitrogen atmosphere. After cooling the obtained reaction liquid to room temperature, water (100 parts) was added, and solid content was fractionated by filtration. The resulting solid was washed with acetone and DMF, dried, and purified by sublimation to obtain the compound represented by No. 2 (0.84 parts, yield 55%).

No. of the specific example obtained above. The results of EI-MS measurement of the compound represented by 2 were as follows.
EI-MS m/z: Calcd for _C38H22O2 [M ⁺ ] _{: 510.59} . Found: 510.36.

Example 3 (Synthesis of Condensed Polycyclic Aromatic Compound Represented by Specific Example No. 4)
(Step 4) Specific example No. Synthesis of Condensed Polycyclic Aromatic Compound Represented by 4 In DMF (150 parts), ACS Appl. Energy Mater. 2020, 3 (11), 2,6-dibromoanthracene synthesized by the method described in 10752 (1.5 parts), 2-trimethylstannyl-6- synthesized by the method described in JP-A-2020-189793 Phenyl(naphtho[2,3-b]thiophene) (5.7 parts), copper (I) iodide (0.09 parts) and tetrakis(triphenylphosphine)palladium (0.15 parts) were added, and a nitrogen atmosphere was added. The mixture was stirred at 80° C. for 5 hours. After cooling the obtained reaction liquid to room temperature, water (100 parts) was added, and solid content was fractionated by filtration. The obtained solid was washed with acetone and DMF, dried, and then purified by sublimation to give specific example No. A compound represented by 4 (1.1 parts, 35% yield) was obtained.

No. of the specific example obtained above. The results of EI-MS measurement of the compound represented by 4 were as follows.
EI-MS m/z: Calcd for _C50H30S2 [M ⁺ ]: 694.91. Found _{: 694.56}

Example 4 (Synthesis of Condensed Polycyclic Aromatic Compound Represented by Specific Example No. 5)
(Step 5) Synthesis of Intermediate Compound Represented by Formula 3 below To dehydrated THF (120 parts), Chemical Communications. 2012, 48(47), 6-phenyl(naphtho[2,3-b]furan) (3.0 parts) synthesized by the method described in 5892 is added, cooled to −78° C. under a nitrogen atmosphere, and 1 A THF/hexane solution (21.0 parts) of .0M lithium diisopropylamide was added and stirred for 1 hour. Then, trimethyltin chloride (3.2 parts) was added, and the mixture was stirred for 1 hour, warmed to room temperature, and further stirred for 2 hours. The resulting reaction solution was quenched with water (100 parts), washed with an aqueous potassium fluoride solution, and then separated and extracted with ethyl acetate. The obtained organic layer was dried using sodium sulfate, and the solvent was distilled off under reduced pressure. The obtained solid was purified with a silica gel column (developing solvent: hexane) to obtain an intermediate compound represented by the following formula 3 (1.8 parts, yield 37%).

(Step 6) Specific example No. Synthesis of condensed polycyclic aromatic compound represented by 5 To toluene (120 parts), ACS Appl. Energy Mater. 2020, 3(11), 2,6-dibromoanthracene synthesized by the method described in 10752 (0.5 parts), the intermediate compound represented by formula 3 obtained in step 5 (1.8 parts), Tetrakis(triphenylphosphine)palladium (0.09 parts) was added, and the mixture was stirred at 90°C for 5 hours under a nitrogen atmosphere. After cooling the obtained reaction liquid to room temperature, water (100 parts) was added, and solid content was fractionated by filtration. The obtained solid was washed with acetone and DMF, dried, and then purified by sublimation to give specific example No. A compound represented by 5 (0.43 parts, 44% yield) was obtained.

No. of the specific example obtained above. The results of EI-MS measurement of the compound represented by 5 were as follows.
EI-MS m/z: Calcd for _C50H30O2 [M ⁺ ] _{: 662.79} . Found: 662.26

Example 6 (Preparation and Evaluation of Organic Photoelectric Conversion Device of Compound Represented by Specific Example No. 1 Obtained in Example 1)
No. 1 of the specific example obtained in Example 1 was applied to an ITO transparent conductive glass (manufactured by Geomatec, ITO film thickness: 150 nm). A condensed polycyclic aromatic compound represented by 1 was formed into a film with a thickness of 85 nm by resistance heating vacuum deposition. Next, a 100-nm aluminum film was formed as an electrode in vacuum to produce the organic photoelectric conversion element 1 of the present invention. The light-dark ratio was 640,000 when a voltage of 5 V was applied using ITO and aluminum as electrodes and light was irradiated with a light wavelength of 450 nm.

Example 7 (Preparation and Evaluation of Organic Photoelectric Conversion Device of Compound Represented by Specific Example No. 2 Obtained in Example 2)
No. 1 of the specific example obtained in Example 1. The condensed polycyclic aromatic compound represented by No. 1 of the specific example obtained in Example 2 was used. An organic photoelectric conversion element 2 was produced in the same manner as in Example 6, except that the condensed polycyclic aromatic compound represented by 2 was used. The light-dark ratio was 410,000 when a voltage of 5 V was applied using ITO and aluminum as electrodes and light was irradiated with a light wavelength of 450 nm.

Example 8 (Preparation and Evaluation of Organic Photoelectric Conversion Device of Compound Represented by Specific Example No. 4 Obtained in Example 3)
No. 1 of the specific example obtained in Example 1. The condensed polycyclic aromatic compound represented by No. 1 of the specific example obtained in Example 3. An organic photoelectric conversion device 3 was produced in the same manner as in Example 6, except that the condensed polycyclic aromatic compound represented by 4 was used. The light-dark ratio was 310,000 when a voltage of 5 V was applied using ITO and aluminum as electrodes, and light with a wavelength of 450 nm was irradiated.

Example 9 (Preparation and Evaluation of Organic Photoelectric Conversion Device of Compound Represented by Specific Example No. 5 Obtained in Example 4)
No. 1 of the specific example obtained in Example 1. The condensed polycyclic aromatic compound represented by No. 1 of the specific example obtained in Example 4 was used. An organic photoelectric conversion element 4 was produced in the same manner as in Example 6, except that the condensed polycyclic aromatic compound represented by 5 was used. The light-dark ratio was 570,000 when a voltage of 5 V was applied using ITO and aluminum as electrodes and light was irradiated with a light wavelength of 450 nm.

Comparative Example 1 (Synthesis of condensed polycyclic aromatic compound represented by formula R1 below)
(Step 7) Synthesis of a condensed polycyclic aromatic compound represented by the following formula R1 In DMF (100 parts), 2,6-dibromobenzo[1,2-b:4 synthesized by the method described in WO2017/159025A1 ,5-b′]dithiophene (1.2 parts), 2-trimethylstannyl (naphtho[2,3-b]thiophene) (3.6 parts), copper (I) iodide (0.17 parts), Tetrakis(triphenylphosphine)palladium (0.20 parts) was added, and the mixture was stirred at 80°C for 5 hours under a nitrogen atmosphere. After cooling the obtained reaction liquid to room temperature, water (100 parts) was added, and solid content was fractionated by filtration. The obtained solid was washed with acetone and DMF, dried, and purified by sublimation to obtain a compound represented by the following formula R1 (1.3 parts, yield 69%).

The results of EI-MS measurement of the compound represented by formula R1 obtained above were as follows.
EI _- MS m/z ^{: Calcd for C34H18S4 [M+} _{] :} 554.76. Found: 554.12

Comparative Example 2 (Preparation and Evaluation of Organic Photoelectric Conversion Device of Compound Represented by R1 Obtained in Comparative Example 1)
No. 1 of the specific example obtained in Example 1. An organic photoelectric conversion device R1D was obtained in the same manner as in Example 6, except that the condensed polycyclic aromatic compound represented by Formula 1 was changed to the condensed polycyclic aromatic compound represented by Formula R1 obtained in Comparative Example 1. was made. The light-dark ratio was 2,100 when a voltage of 5 V was applied using ITO and aluminum as electrodes and light was irradiated with a light wavelength of 450 nm.

Comparative Example 3 (Preparation and Evaluation of Organic Photoelectric Conversion Device of Compound Represented by Formula R2)
No. 1 of the specific example obtained in Example 1. An organic photoelectric conversion element R2D was produced in the same manner as in Example 6, except that the condensed polycyclic aromatic compound represented by Formula 1 was changed to a condensed polycyclic aromatic compound represented by the following formula R2. An attempt was made to apply a voltage of 5 V using ITO and aluminum as electrodes, but the withstand voltage was low and the contrast ratio could not be measured.

The organic photoelectric conversion device using the condensed polycyclic aromatic compound represented by the formula (1) of the present invention has an absorption band in the blue light region around 450 nm and exhibits a large light-dark current ratio. It can be used for organic photoelectric conversion elements and organic imaging elements, materials thereof, and the like.

(Fig. 1)
1 Insulating Part 2 Upper Electrode 3 Electron Blocking Layer 4 Photoelectric Conversion Layer 5 Hole Blocking Layer 6 Lower Electrode 7 Insulating Substrate or Other Photoelectric Conversion Element

Claims (11)

General formula (1)

(In the formula (1), each X independently represents an oxygen atom, a sulfur atom or a selenium atom, and each of R ₁ to R ₁₂ independently represents a hydrogen atom or a residue obtained by removing one hydrogen atom from an aromatic compound. .)
Condensed polycyclic aromatic compound represented by. 2. The condensed polycyclic aromatic compound according to claim 1, wherein each X is independently an oxygen atom or a sulfur atom. 3. The condensed polycyclic aromatic compound according to claim 1 or 2, wherein _R1 to _R12 are each independently a hydrogen atom or a residue obtained by removing one hydrogen atom from an aromatic hydrocarbon compound. 4. The condensed polycyclic aromatic compound according to any one of claims 1 to 3, _wherein R3 to _R6 and _R9 to _R12 are hydrogen atoms. 5. The condensed polycyclic aromatic compound according to claim 4, wherein _R2 and _R8 are hydrogen atoms. 6. The condensed polycyclic aromatic compound according to claim 5, wherein _R1 and _R7 are each independently a hydrogen atom, a phenyl group, a biphenyl group or a naphthyl group. 7. The condensed polycyclic aromatic compound of claim 6, wherein _R1 and _R7 are the same. A material for an organic photoelectric conversion device, comprising the condensed polycyclic aromatic compound according to claim 1 . An organic thin film comprising the condensed polycyclic aromatic compound according to any one of claims 1 to 7. An organic photoelectric conversion device comprising the organic thin film according to claim 9 . An organic photoelectric conversion device comprising the organic thin film according to claim 9 in a photoelectric conversion layer.

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