JP7390320B2 - Dibenzopyrromethene boron chelate compounds, near-infrared absorption materials, organic thin films and organic electronic devices - Google Patents

Description

The present invention relates to a novel dibenzopyromethene boron chelate compound having an absorption band in the near-infrared region, and near-infrared light-absorbing materials, thin films, and organic electronic devices containing the compound.

Near-infrared light absorbing materials having an absorption band in the wavelength range of 700 to 2500 nm have been considered for use in various industrial applications. Specific applications include optical information recording media such as CD-R (Compact Disc-Recordable); printing applications such as thermal CTP (Computer To Plate), flash toner fixing, and laser thermal recording; heat-blocking films, etc. It will be done. Furthermore, by taking advantage of its characteristic of selectively absorbing light in a specific wavelength range, it is also used in near-infrared light cut filters used in PDPs (Plasma Display Panels), films for controlling plant growth, and the like. Furthermore, by dissolving or dispersing a dye containing a near-infrared light-absorbing material in a solvent, it is also possible to use it as a near-infrared light-absorbing ink. Printed matter using near-infrared light-absorbing ink can only be read with a near-infrared light detector and is difficult to visually recognize (invisible images), so it is difficult to recognize it visually (invisible image), so it is difficult to recognize it visually (invisible image). Used for etc.

As such near-infrared light-absorbing materials for invisible image formation, inorganic near-infrared light-absorbing materials and organic near-infrared light-absorbing materials are known. Among these, examples of inorganic near-infrared light absorbing materials include rare earth metals such as ytterbium, copper phosphate crystallized glass, and the like. However, these inorganic near-infrared light-absorbing materials do not have sufficient light absorption ability in the near-infrared region, so a large amount of the near-infrared light-absorbing material is required per unit area in order to form an invisible image. Moreover, when a visible image is further formed on top of the formed invisible image, the unevenness of the surface of the invisible image serving as the base may affect the surface condition of the visible image.

On the other hand, since organic near-infrared light absorbing materials have sufficient absorption of light in the near-infrared region, the amount of near-infrared absorbing material used per unit area required to form an invisible image is lower than that of inorganic near-infrared light absorbing materials. It is possible to reduce the amount of light compared to near-infrared light-absorbing materials, and the disadvantages that occur when using inorganic near-infrared light-absorbing materials do not occur. Therefore, many organic near-infrared light absorbing materials have been developed to date.

By the way, organic electronic devices not only do not contain rare metals as raw materials and can be supplied stably, but also have flexibility that inorganic materials do not have and can be manufactured using a wet film formation method. There has been a lot of interest in it in recent years. Specific examples of organic electronic devices include organic EL elements, organic solar cell elements, organic photoelectric conversion elements, and organic transistor elements, and further, applications that take advantage of the characteristics of organic materials are being considered.

Among these organic electronic devices, research on organic solar cell elements and organic photoelectric conversion elements has been conducted mainly on light absorption characteristics in the visible light region. Currently, studies are being conducted to improve both the photoelectric conversion efficiency and suppress the dark current value using a bulk heterojunction structure. In addition to further improving performance, absorption characteristics in the near-infrared region are beginning to attract attention in order to develop new applications such as security applications and biological imaging applications. However, the application of near-infrared light-absorbing dyes to organic solar cell elements and organic photoelectric conversion elements has just begun, and there are not many reports. For example, in Patent Document 1, studies have been conducted with the aim of applying existing dyes such as squarylium, which is one of the infrared absorbing materials mentioned above, to photoelectric conversion materials in the near-infrared region. Organic electronic materials using squarylium have poor robustness and are not practical.

Non-Patent Documents 1 and 2 report on boron-dipyrromethene (hereinafter referred to as "BODIPY") dye as a dye that exhibits an absorption band to a fluorescence band in the red or near-infrared light region and has excellent fastness. is being done.
Furthermore, Patent Document 2 states that the simple BODIPY dye has a strong absorption band around 500 nm, and by expanding the π-conjugated system and introducing an aromatic group with an electron-donating substituent, it can extend into the near-infrared region. It is described that it is possible to extend the absorption wavelength.

Further, Patent Documents 3 to 5 describe that by BO chelating a compound having a BODIPY skeleton, the light fastness of the compound can be further improved and the absorption wavelength can be shifted to the longer wavelength side. In particular, Patent Documents 3 and 4 also describe examples in which these B--O chelated compounds are applied to organic solar cell elements and organic photoelectric conversion elements. However, the compounds described in Patent Documents 3 and 4 cannot be said to sufficiently lengthen the absorption wavelength, and Patent Document 5 does not mention anything about absorption wavelengths or photoelectric conversion properties in the near-infrared region. .
Patent Document 6 exemplifies a photoelectric conversion element that uses a thiophene ring and a B--O chelated compound and has absorption in the near-infrared region, but the contrast ratio for light exceeding 900 nm is low, and the near-infrared In order to use it for photoelectric conversion purposes, it is necessary to further increase the wavelength of the photoelectric conversion wavelength and increase the sensitivity of the photoelectric conversion characteristics in the near-infrared region.

JP2017-137264A Japanese Patent Application Publication No. 1999-255774 Japanese Patent Application Publication No. 2012-199541 Japanese Patent Application Publication No. 2016-166284 International Publication No. 2013/035303 International Publication No. 2018/079653

Chem. Soc. Rev. , 2014, 43, 4778-4823 Chem. Rev. , 2007, 107, 4891-4932

The objects of the present invention are an organic compound that has broad absorption in the near-infrared region and excellent photoelectric conversion efficiency in the near-infrared region, a near-infrared light-absorbing material containing the compound, and the near-infrared light-absorbing material. An object of the present invention is to provide an organic thin film containing the organic thin film, and an organic electronic device and an organic photoelectric conversion element containing the organic thin film.

The present inventors have studied to solve the above problems, and have developed a new dibenzopyromethene boron chelate compound that exhibits sufficient performance when used in organic electronic devices. The present inventors have discovered that an organic electronic device that has been previously used can function as a near-infrared photoelectric conversion element, and have completed the present invention. That is, the present invention is as follows.
[1] The following formula (1)

(In formula (1), R ₁ to R ₈ are each independently a hydrogen atom, an aliphatic hydrocarbon group, an alkoxy group, an alkylthio group, an aromatic group, a heterocyclic group, a halogen atom, a hydroxyl group, a mercapto group, a nitro group) , represents a substituted amino group, an unsubstituted amino group, a cyano group, a sulfo group, or an acyl group.However, at least one of R ₁ to R ₄ represents other than a hydrogen atom, and at least one of R ₅ to R ₈ represents an atom other than a hydrogen _atom.R9 to _R12 each independently represent a hydrogen atom, an aliphatic hydrocarbon group, an alkoxy group, an alkylthio group, an aromatic group, a heterocyclic group, a halogen atom, a hydroxyl group, a mercapto group, a nitro group , a substituted amino group, an unsubstituted amino group, a cyano group, a sulfo group or an acyl group),
[2] At least one of R ₁ to R ₄ is an aliphatic hydrocarbon group, aromatic group, heterocyclic group, or halogen atom, and at least one of R ₅ to R ₈ is an aliphatic hydrocarbon group, aromatic group, or a halogen atom. The compound according to the preceding item [1], which is a group, a heterocyclic group, or a halogen atom,
[3] The compound according to the above item [2], wherein at least one of R ₁ to R ₄ is a halogen atom, and at least one of R ₅ to R ₈ is a halogen atom,
[4] The compound according to the above item [2], wherein at least one of R ₁ to R ₄ is an aromatic group or a heterocyclic group, and at least one of R ₅ to R ₈ is an aromatic group or a heterocyclic group ,
[5] The preceding item where R ₁ and R ₈ are the same, R ₂ and R ₇ are the same, R ₃ and R ₆ are the same, and R ₄ and R ₅ are the same [1] The compound according to any one of [4] to
[6] At least one of R ₉ and R ₁₀ is an aromatic group or a heterocyclic group, and at least one of R ₁₁ and R ₁₂ is an aromatic group or a heterocyclic group [1] to [5] A compound according to any one of
[7] The compound according to the preceding item [6], wherein R ₉ and R ₁₂ are hydrogen atoms, and R ₁₀ and R ₁₁ are aromatic groups or heterocyclic groups,
[8] R ₁₀ and R ₁₁ are the following formula (2)

(In formula (2), R ₂₁ to R ₂₅ are each independently a hydrogen atom, an alkoxy group, an alkylthio group, an aromatic group, a heterocyclic group, a substituted amino group, an unsubstituted amino group, an electron-accepting substituent, or represents an atom, and R ₂₁ and R ₂₂ may be combined, or R ₂₂ and R ₂₃ may be combined to form an aromatic ring or a heterocycle.However, at least one of R ₂₁ to R ₂₅ is represents an electron-accepting substituent or atom, or R ₂₁ and R ₂₂ combine, or R ₂₂ and R ₂₃ combine to form an electron-accepting aromatic ring or heterocycle). The compound according to any one of the preceding items [1] to [7], which is a substituent
[9] At least one of R ₂₁ to R ₂₅ is a halogen atom, formyl group, acetyl group, alkoxycarbonyl group, trifluoromethyl group, cyano group, nitro group, toluenesulfonyl group, methanesulfonyl group, trifluoromethanesulfonyl group, An electron-accepting substituent or atom selected from the group consisting of a pyridyl group, a quinolyl group, a pyrazyl group, a quinoxalyl group, a thiazolyl group, a benzothiazolyl group, an indolyl group, a benzothiadiazolyl group, a succinimidoyl group, and a phthalimidoyl group. A certain compound described in the preceding item [8],
[10] The compound according to the preceding item [8], in which R ₂₁ and R ₂₂ are combined, or R ₂₂ and R ₂₃ are combined to form a heterocycle containing a nitrogen atom and/or a sulfur atom,
[11] A near-infrared light-absorbing material containing the compound described in any one of the preceding sections [1] to [10],
[12] An organic thin film containing the near-infrared light absorbing material according to the preceding item [11],
[13] An organic electronics device comprising the organic thin film according to item [12], and [14] an organic photoelectric conversion element comprising the organic thin film according to item [12].

The organic thin film using the novel compound of the present invention has a main absorption band in the near-infrared region. Further, by using the compound and/or the organic thin film, a near-infrared photoelectric conversion element can be realized. This compound can be used for various organic electronic devices.

FIG. 1 shows a cross-sectional view illustrating an embodiment of the organic photoelectric conversion element of the present invention. FIG. 2 shows a schematic cross-sectional view showing an example of the layer structure of an organic electroluminescent device.

Hereinafter, the content of the present invention will be explained in detail. The explanation of the constituent elements described herein is based on typical embodiments and specific examples of the present invention, but the present invention is not limited to those embodiments and specific examples. In this specification, the near-infrared region refers to the wavelength region of light within the range of 750 to 2500 nm, and the near-infrared light-absorbing material (or dye) has a main absorption wavelength in the near-infrared light region. A near-infrared emitting material (or dye) means a material (or dye) that emits light in the near-infrared region.

The compound of the present invention is represented by the following formula (1).

In formula (1), R ₁ to R ₈ each independently represent a hydrogen atom, an aliphatic hydrocarbon group, an alkoxy group, an alkylthio group, an aromatic group, a heterocyclic group, a halogen atom, a hydroxyl group, a mercapto group, a nitro group, Represents a substituted amino group, unsubstituted amino group, cyano group, sulfo group, or acyl group. However, at least one of R ₁ to R ₄ represents an atom other than a hydrogen atom, and at least one of R ₅ to R ₈ represents an atom other than a hydrogen atom.

The aliphatic hydrocarbon group represented by R ₁ to R ₈ in formula (1) can be a saturated or unsaturated linear, branched, or cyclic aliphatic hydrocarbon, and the number of carbon atoms thereof is 1. The number is preferably from 30 to 30, more preferably from 1 to 20, and even more preferably from 3 to 10. Here, specific examples of saturated or unsaturated linear, branched or cyclic aliphatic hydrocarbon groups include methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, iso-butyl group. , allyl group, t-butyl group, n-pentyl group, n-hexyl group, n-octyl group, n-decyl group, n-dodecyl group, n-tridecyl group, n-tetradecyl group, n-cetyl group, n - heptadecyl group, n-butenyl group, 2-ethylhexyl group, 3-ethylheptyl group, 4-ethyloctyl group, 2-butyloctyl group, 3-butylnonyl group, 4-butyldecyl group, 2-hexyldecyl group, Examples include 3-octylundecyl group, 4-octyldodecyl group, 2-octyldodecyl group, 2-decyltetradecyl group, cyclopropyl group, cyclobutyl group, cyclopentyl group, and cyclohexyl group.
The aliphatic hydrocarbon groups represented by R ₁ to R ₈ in formula (1) are preferably linear or branched aliphatic hydrocarbon groups, including linear or branched alkyl groups. More preferably, n-butyl group, n-hexyl group, n-octyl group, n-decyl group, n-dodecyl group, 2-ethylhexyl group, 2-methylpropyl group or 2-butyloctyl group. More preferably, n-hexyl group, n-octyl group or 2-methylpropyl group is particularly preferable.

The alkoxy group represented by R ₁ to R ₈ in formula (1) is a substituent in which an oxygen atom and an alkyl group are bonded, and examples of the alkyl group in the alkoxy group include R 1 to R ₈ in formula (1). The alkyl groups described as specific examples in the section of the aliphatic hydrocarbon group represented by R ₈ can be mentioned. The alkoxy group represented by R ₁ to R ₈ in formula (1) may have a substituent such as an alkoxy group.
The alkylthio group represented by R ₁ to R ₈ in formula (1) is a substituent in which a sulfur atom and an alkyl group are bonded, and examples of the alkyl group in the alkylthio group include R 1 to R ₈ in formula (1). The alkyl groups described as specific examples in the section of the aliphatic hydrocarbon group represented by R ₈ can be mentioned. The alkylthio group represented by R ₁ to R ₈ in formula (1) may have a substituent such as an alkylthio group.

The aromatic group represented by R ₁ to R ₈ in formula (1) is not particularly limited as long as it is a residue obtained by removing one hydrogen atom from the aromatic ring of an aromatic compound, and includes, for example, a phenyl group, a biphenyl group, Examples include an indenyl group, a naphthyl group, an anthryl group, a fluorenyl group, a pyrenyl group, a phenanthyl group, and a mestyl group, with a phenyl group or a naphthyl group being preferred, and a phenyl group being more preferred. Incidentally, the aromatic compound that can become an aromatic group may have a substituent, and the substituent that may have this is not particularly limited, but may include an alkyl group having 1 to 4 carbon atoms, a halogen atom, or a phenyl group. A group is preferable, and a methyl group, a halogen atom, or a phenyl group is more preferable.

The heterocyclic group represented by R ₁ to R ₈ in formula (1) is not particularly limited as long as it is a residue obtained by removing one hydrogen atom from the heterocycle of a heterocyclic compound, and includes, for example, a furanyl group, a thienyl group, Thienothienyl group, pyrrolyl group, imidazolyl group, N-methylimidazolyl group, thiazolyl group, oxazolyl group, pyridyl group, pyrazyl group, pyrimidyl group, quinolyl group, indolyl group, benzopyrazyl group, benzopyrimidyl group, benzothienyl group, benzothiazolyl group, pyri Dinothiazolyl group, benzimidazolyl group, pyridinoimidazolyl group, N-methylbenzimidazolyl group, pyridino-N-methylimidazolyl group, benzoxazolyl group, pyridinooxazolyl group, benzothiadiazolyl group, pyridinothia Examples include diazolyl group, benzoxadiazolyl group, pyridinooxadiazolyl group, carbazolyl group, phenoxazinyl group and phenothiazinyl group, and thienyl group, thienothienyl group, thiazolyl group, pyridyl group, benzothiazolyl group, benzothiadiazolyl group. or a pyridinothiadiazolyl group, and a thienyl group, a thiazolyl group, a benzothiazolyl group, or a benzothiadiazolyl group is more preferable. In addition, the heterocyclic compound which can become a heterocyclic group may have a substituent, and the substituent which may have this is not specifically limited.

Examples of the halogen atom represented by R ₁ to R ₈ in formula (1) include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, preferably a fluorine atom or a chlorine atom, and more preferably a fluorine atom.

The substituted amino group represented by R ₁ to R ₈ in formula (1) is a substituent in which one or two hydrogen atoms of the amino group are substituted with a substituent. The substituent of the substituted amino group is preferably an alkyl group or an aromatic group, and more preferably an aromatic group. Specific examples of these substituents include the alkyl groups described in the section of the aliphatic hydrocarbon groups represented by R ₁ to R ₈ in formula (1), and the aromatic groups represented by R ₁ to R ₈ in formula (1). The same things as the group can be mentioned.
The unsubstituted amino group represented by R ₁ to R ₈ in formula (1) means an NH ₂ group.
The acyl group represented by R ₁ to R ₈ in formula (1) is a substituent in which a carbonyl group and an aromatic group or an alkyl group are bonded, and the alkyl group and aromatic group in the acyl group are represented by the formula ( Examples include the alkyl groups described in the section of the aliphatic hydrocarbon groups represented by R ₁ to R ₈ in 1) and the same aromatic groups as the aromatic groups represented by R ₁ to R ₈ in formula (1).

As R ₁ to R ₈ in formula (1), at least one of R ₁ to R ₄ is an aliphatic hydrocarbon group, an aromatic group, a heterocyclic group, a halogen atom, or a substituted amino group, and R ₅ to It is preferable that at least one of R ₈ is an aliphatic hydrocarbon group, an aromatic group, a heterocyclic group, a halogen atom, or a substituted amino group, and at least one of R ₁ to R ₄ is an aliphatic hydrocarbon group or an aromatic group. , a heterocyclic group, or a halogen atom, and at least one of R ₅ to R ₈ is preferably an aliphatic hydrocarbon group, an aromatic group, a heterocyclic group, or a halogen atom, and R ₁ to R ₄ are preferably One of them is an aliphatic hydrocarbon group, an aromatic group, a heterocyclic group, or a halogen atom, and the remaining three are hydrogen atoms, and one of R ₅ to R ₈ is an aliphatic hydrocarbon group, an aromatic group, or a halogen atom. It is more preferable that the remaining three are hydrogen atoms, and one of R ₁ to R ₄ is an aromatic group, a heterocyclic group, or a halogen atom, and the remaining three are hydrogen atoms. It is particularly preferable that three of R 5 to R 8 are hydrogen atoms, one of R ₅ to R ₈ is an aromatic group, a heterocyclic group, or a halogen atom, and _{the remaining three are} hydrogen atoms; Most preferably, one of them is a halogen atom and the remaining three are hydrogen atoms, and one of R ₅ to R ₈ is a halogen atom and the remaining three are hydrogen atoms.

Furthermore, one of the above R ₁ to R ₄ is a substituent or a halogen atom, the remaining three are hydrogen atoms, and one of R ₅ to R ₈ is a substituent or a halogen atom. In the embodiment in which the remaining three are hydrogen atoms, the substitution positions of the substituents or halogen atoms are preferably R ₂ and R ₇ or R ₃ and R ₆ . Note that the substituent refers to those listed as R ₁ to R ₈ other than hydrogen atoms and halogen atoms. More specifically, R ₂ and R ₇ are each independently an aliphatic hydrocarbon group, an aromatic group, a heterocyclic group, a halogen atom, or a substituted amino group, and R ₁ , R ₃ to R ₆ and R ₈ are hydrogen atoms. or R ₃ and R ₆ are each independently an aliphatic hydrocarbon group, an aromatic group, a heterocyclic group, a halogen atom, or a substituted amino group, and R ₁ , R ₂ , R ₄ , R ₅ , R ₇ and R ₈ are preferably hydrogen atoms, R ₂ and R ₇ are each independently an aliphatic hydrocarbon group, an aromatic group, a heterocyclic group, or a halogen atom, and R ₁ , R ₃ to R ₆ and R ₈ is a hydrogen atom, or R ₃ and R ₆ are each independently an aliphatic hydrocarbon group, an aromatic group, a heterocyclic group, or a halogen atom, and R ₁ , R ₂ , R ₄ , R ₅ , R ₇ It is more preferable that R ₈ is a hydrogen atom, R ₂ and R ₇ are each independently an aromatic group, a heterocyclic group, or a halogen atom, and R ₁ , R ₃ to R ₆ and R ₈ are hydrogen atoms. Or, R ₃ and R ₆ are each independently an aromatic group, a heterocyclic group, or a halogen atom, and R ₁ , R ₂ , R ₄ , R ₅ , R ₇ and R ₈ are hydrogen atoms. Preferably, R ₂ and R ₇ are each independently a halogen atom, and R ₁ , R ₃ to R ₆ and R ₈ are hydrogen atoms, or R ₃ and R ₆ are each independently a halogen atom, and R ₁ , R ₂ , R ₄ , R ₅ , R ₇ and R ₈ are particularly preferably hydrogen atoms.

Furthermore, as R ₁ to R ₈ in formula (1), R ₁ and R ₈ are the same, R ₂ and R ₇ are the same, R ₃ and R ₆ are the same, and It is also a preferred embodiment that R ₄ and R ₅ are the same.
For example, in the case of an embodiment in which R ₂ and R ₇ or R ₃ and R ₆ described above are substituents or halogen atoms, and the others are hydrogen atoms, both R ₂ and R ₇ are the same aliphatic A hydrocarbon group, an aromatic group, a heterocyclic group, a halogen atom, or a substituted amino group in which R ₁ , R ₃ to R ₆ and R ₈ are hydrogen atoms, or both R ₃ and R ₆ are the same aliphatic group. group hydrocarbon group, aromatic group, heterocyclic group, halogen atom or substituted amino group, in which R ₁ , R ₂ , R ₄ , R ₅ , R ₇ and R ₈ are preferably hydrogen atoms, and R ₂ and R ₇ are the same aliphatic hydrocarbon group, aromatic group, heterocyclic group, or halogen atom, and R ₁ , R ₃ to R ₆ and R ₈ are hydrogen atoms, or R ₃ and R ₆ It is more preferable that both are the same aliphatic hydrocarbon group, aromatic group, heterocyclic group or halogen atom, and R ₁ , R ₂ , R ₄ , R ₅ , R ₇ and R ₈ are hydrogen atoms. , R ₂ and R ₇ are both the same aromatic group, heterocyclic group, or halogen atom, and R ₁ , R ₃ to R ₆ and R ₈ are hydrogen atoms, or both R ₃ and R ₆ are It is more preferable that R ₁ , R ₂ , R ₄ , R ₅ , R ₇ and R ₈ are hydrogen atoms, and both R ₂ and R ₇ are the same aromatic group, heterocyclic group or halogen atom. Either they are the same halogen atoms and R ₁ , R ₃ to R ₆ and R ₈ are hydrogen atoms, or R ₃ and R ₆ are both the same halogen atoms and R ₁ , R ₂ , R ₄ , R It is particularly preferred that ₅ , R ₇ and R ₈ are hydrogen atoms.

Furthermore, two or more of R ₁ to R ₄ in formula (1) are each independently an aliphatic hydrocarbon group, an aromatic group, a heterocyclic group, a halogen atom, or a substituted amino group, and R ₅ to It is also preferable that two or more of R ₈ are each independently an aliphatic hydrocarbon group, an aromatic group, a heterocyclic group, a halogen atom, or a substituted amino group, and two or more of R ₁ to R ₄ are Each independently represents an aliphatic hydrocarbon group, an aromatic group, a heterocyclic group, or a halogen atom, and two or more of R ₅ to R ₈ each independently represent an aliphatic hydrocarbon group, an aromatic group, a heterocyclic group, or a halogen atom. More preferably, it is a ring group or a halogen atom, and two or more of R ₁ to R ₄ are each independently an aromatic group, a heterocyclic group, or a halogen atom, and two or more of R ₅ to R ₈ are It is further preferred that two or more are each independently an aromatic group, a heterocyclic group, or a halogen atom.
Furthermore, two of R ₁ to R ₄ are each independently an aliphatic hydrocarbon group, an aromatic group, a heterocyclic group, a halogen atom, or a substituted amino group, and the remaining two are hydrogen atoms, and R Preferably, two of ₅ to R ₈ are each independently an aliphatic hydrocarbon group, an aromatic group, a heterocyclic group, a halogen atom, or a substituted amino group, and the remaining two are hydrogen atoms, and R ₁ to Two of R ₄ are each independently an aliphatic hydrocarbon group, an aromatic group, a heterocyclic group, or a halogen atom, the remaining two are hydrogen atoms, and two of R ₅ to R ₈ are each More preferably, the remaining two are independently aliphatic hydrocarbon groups, aromatic groups, heterocyclic groups, or halogen atoms, and one of R ₁ to R ₄ is a halogen atom, and One of them is a halogen atom, an aromatic group, or a heterocyclic group, and the remaining two are hydrogen atoms, and one of R ₅ to R ₈ is a halogen atom, and the other one is a halogen atom, an aromatic group, and the other one is a halogen atom, an aromatic group, or a heterocyclic group. It is more preferable that the remaining two atoms in the group or heterocyclic group are hydrogen atoms.

In formula (1), R ₉ to R ₁₂ each independently represent a hydrogen atom, an aliphatic hydrocarbon group, an alkoxy group, an alkylthio group, an aromatic group, a heterocyclic group, a halogen atom, a hydroxyl group, a mercapto group, a nitro group, Represents a substituted amino group, unsubstituted amino group, cyano group, sulfo group or acyl group.
The aliphatic hydrocarbon group, alkoxy group, alkylthio group, aromatic group, heterocyclic group, halogen atom, substituted amino group, and acyl group represented by R ₉ to R ₁₂ in formula (1) include R in formula (1). The same aliphatic hydrocarbon groups, alkoxy groups, alkylthio groups, aromatic groups, heterocyclic groups, halogen atoms, substituted amino groups, and acyl groups represented by ₁ to R ₈ can be mentioned, and preferred ones are also the same.

R ₉ to R ₁₂ in formula (1) are preferably each independently a hydrogen atom, an aromatic group, a heterocyclic group, a halogen atom, or a cyano group, and each independently an aromatic group or a heterocyclic group. It is more preferable.
More specifically, at least one of R ₉ and R ₁₀ is an aromatic group, a heterocyclic group, a halogen atom, or a cyano group, and at least one of R ₁₁ and R ₁₂ is an aromatic group, a heterocyclic group, or a halogen atom. or a cyano group, at least one of R ₉ and R ₁₀ is an aromatic group or a heterocyclic group, and at least one of R ₁₁ and R ₁₂ is an aromatic group or a heterocyclic group. More preferably, R ₁₀ and R ₁₁ are an aromatic group or a heterocyclic group, R ₉ and R ₁₂ are hydrogen atoms, and R ₁₀ and R ₁₁ are an aromatic group or a heterocyclic group. It is even more preferable that there be.
More specifically, at least one of R ₉ and R ₁₀ is a substituent represented by the following formula (2), and at least one of R ₁₁ and R ₁₂ is a substituent represented by the following formula (2). It is preferable that R ₁₀ and R ₁₁ are substituents represented by the following formula (2), R ₉ and R ₁₂ are hydrogen atoms, and R ₁₀ and R ₁₁ are the same or a different substituent represented by the following formula (2), R ₉ and R ₁₂ are hydrogen atoms, and R ₁₀ and R ₁₁ are represented by the same formula (2) below. Particularly preferred is a substituent.

In formula (2), R ₂₁ to R ₂₅ are each independently a hydrogen atom, an alkoxy group, an alkylthio group, an aromatic group, a heterocyclic group, a substituted amino group, an unsubstituted amino group, an acyl group, or an electron-accepting It represents a substituent or an atom, and R ₂₁ and R ₂₂ may be combined, or R ₂₂ and R ₂₃ may be combined to form an aromatic ring or a heterocycle. However, at least one of R ₂₁ to R ₂₅ represents an electron-accepting substituent or atom, or R ₂₁ and R ₂₂ combine, or R ₂₂ and R ₂₃ combine to form an electron-accepting aromatic Forms a ring or heterocycle.
The alkoxy group, alkylthio group, aromatic group, heterocyclic group, substituted amino group and acyl group represented by R ₂₁ to R ₂₅ in formula (2) include an alkoxy group represented by R ₁ to R ₈ in formula (1); The same groups as the alkylthio group, aromatic group, heterocyclic group, substituted amino group and acyl group can be mentioned, and preferred ones are also the same.

The electron-accepting (electron-withdrawing) substituent or atom represented by at least one of R ₂₁ to R ₂₅ in formula (2) is not particularly limited as long as it is an electron-accepting substituent or atom. , for example, halogen atoms, formyl groups, acetyl groups, alkoxycarbonyl groups, trifluoromethyl groups, cyano groups, nitro groups, toluenesulfonyl groups, methanesulfonyl groups, trifluoromethanesulfonyl groups, etc. known from the Hammett rule, etc., and electron-deficient Examples include heterocycles such as pyridyl group, quinolyl group, pyrazyl group, quinoxalyl group, thiazolyl group, benzothiazolyl group, indolyl group, benzothiadiazolyl group, succinimidoyl group, and phthalimidoyl group. Among these, a halogen atom, an acetyl group, a trifluoromethyl group, a cyano group, a pyridyl group, a thiazolyl group, or a benzothiazolyl group are preferred, and a halogen atom, a cyano group, a thiazolyl group, or a benzothiazolyl group are more preferred.

R ₂₁ and R ₂₂ in formula (2) may be combined, or R ₂₂ and R ₂₃ may be combined to form an aromatic ring or a heterocycle.
Specific examples of the aromatic ring or heterocycle formed by combining R ₂₁ and R ₂₂ or by combining R ₂₂ and R ₂₃ include a benzene ring, a naphthalene ring, a furan ring, a pyrrole ring, an imidazole ring, and a thiophene ring. Examples include five-membered or six-membered aromatic rings or heterocycles such as ring, pyrazole ring, oxazole ring, thiazole ring, pyridine ring, pyrazine ring, triazole ring, oxadiazole ring, and thiadiazole ring.
Among the specific examples of the aromatic ring or heterocycle formed by the combination of R ₂₁ and R ₂₂ or the combination of R ₂₂ and R ₂₃ described above, those having electron-accepting properties include an oxazole ring, a thiazole ring, It is a pyridine ring, a pyrazine ring, a triazole ring, an oxadiazole ring, and a thiadiazole ring, and it is more preferable to form a heterocycle containing a nitrogen atom and/or a sulfur atom.
The aromatic ring or heterocycle formed by combining R ₂₁ and R ₂₂ or by combining R ₂₂ and R ₂₃ may have a substituent, and the substituent that may have it includes: Aliphatic hydrocarbon group, _alkoxy group, alkylthio group, aromatic group, heterocyclic group, halogen atom, hydroxyl group, mercapto group, nitro group, substituted amino group, _{unsubstituted} Examples include amino groups, cyano groups, sulfo groups and acyl groups.

The compound represented by the above formula (1) can be obtained, for example, by the following reaction steps with reference to the description in Tetrahedron Letters, 2010, 51, 1600.

In the above reaction step, step (a) of reacting compound (A) and compound (B) to obtain compound (C) is performed using an ammonium salt (for example, ammonium acetate, ammonium chloride, etc.) in a mixed solvent of alcohol and acetic acid, for example. Alternatively, it can be carried out by adding aqueous ammonia. In addition, when the structures of compound (A) and compound (B) are the same, step (a) can also be performed with compound (A) alone. Next, in step (b) of obtaining compound (D) from compound (C), for example, compound (C) is mixed with boron trifluoride (e.g., diethyl boron trifluoride) in the presence of a tertiary amine (e.g., triethylamine, etc.). ether complexes, etc.). Finally, the step (c) of obtaining the compound represented by formula (1) from compound (D) can be performed, for example, by reacting compound (D) with boron tribromide.
Note that R ₁ to R ₁₂ in compounds (A) to (D) have the same meanings as R ₁ to R ₁₂ in formula (1).
The method for purifying the compound represented by formula (1) is not particularly limited, and for example, washing, recrystallization, column chromatography, vacuum sublimation, etc. can be employed, and these methods can be combined as necessary.

As a specific example of the compound represented by formula (1), No. 1 to No. Compounds represented by 24 are shown below, but the present invention is not limited thereto. Note that the structural formula shown as a specific example merely represents one of the resonance structures, and is not limited to the resonance structure shown.

The near-infrared light absorbing material of the present invention contains a compound represented by the above formula (1).
The content of the compound represented by formula (1) in the near-infrared light-absorbing material of the present invention is limited as long as the near-infrared light absorption ability required in the application using the near-infrared light absorbing material is expressed. Although not particularly limited, the content is usually 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 near-infrared light-absorbing material of the present invention includes compounds other than the compound represented by formula (1) (for example, near-infrared light-absorbing materials (dyes) other than the compound represented by formula (1), etc.) and additives. Agents etc. may be used in combination. Compounds, additives, etc. that can be used in combination are not particularly limited as long as they exhibit the near-infrared light absorption ability required in the application using the near-infrared light-absorbing material.

[Organic thin film]
The organic thin film of the present invention contains the near-infrared light absorbing material of the present invention.
The organic thin film of the present invention can be produced by a general dry film forming method or wet film forming method. Specifically, vacuum processes such as resistance heating evaporation, electron beam evaporation, sputtering, and molecular layering methods, solution processes such as casting, spin coating, dip coating, blade coating, wire bar coating, spray coating, and other coating methods, and inkjet printing. , printing methods such as screen printing, offset printing, and letterpress printing, and soft lithography methods such as microcontact printing.
For forming organic thin films of general near-infrared light-absorbing materials, a process in which the compound is applied in a solution state is desired from the viewpoint of ease of processing, but organic thin films in which organic films are laminated are desired. In this case, it is not suitable because the coating solution may attack the underlying organic film.

In order to realize such a laminated structure, it is appropriate to use a vapor-depositable material that can be used in a dry film-forming method, for example, a dry film-forming method such as resistance heating vapor deposition. Therefore, a near-infrared light-absorbing material that has a main absorption wavelength in the near-infrared region and can be vapor deposited is preferable as the near-infrared photoelectric conversion material.

A combination of the above methods may be used to form each layer. The thickness of each layer cannot be limited as it depends on the resistance value and charge mobility of each material, but it is usually in the range of 0.5 to 5,000 nm, preferably in the range of 1 to 1,000 nm, More preferably, it is in the range of 5 to 500 nm.

The molecular weight of the compound represented by formula (1) above is, for example, 1,500 or less when it is intended to be used by forming an organic thin film containing the compound represented by formula (1) by a vapor deposition method. It is preferably 1,200 or less, more preferably 1,000 or less. The lower limit of molecular weight is the lowest possible molecular weight of the compound represented by formula (1).
Note that the compound represented by formula (1) may be formed into a film by a coating method regardless of its molecular weight. If a coating method is used, it is possible to form a film even with a compound having a relatively large molecular weight.
In addition, the molecular weight in this specification means the value calculated by the EI-GCMS method.

[Organic electronic devices]
The organic electronic device of the present invention includes the organic thin film of the present invention (hereinafter, the organic thin film may be simply referred to as "thin film"). Examples of organic electronic devices include organic thin film transistors, organic photoelectric conversion elements, organic solar cell elements, organic electroluminescent elements (hereinafter referred to as "organic EL elements" or "organic light emitting elements"), organic light emitting transistor elements, and organic light emitting transistor elements. Examples include semiconductor laser elements. The present invention focuses on organic photoelectric conversion elements and organic EL elements, which are expected to be used particularly in near-infrared applications. Here, an organic photoelectric conversion element using a near-infrared light absorption material, an organic EL element using near-infrared emission characteristics, and an organic semiconductor laser element, which are one of the embodiments of the present invention, will be described.
Although not described in detail here, near-infrared light exceeding 700 nm has high transparency to living tissue. Therefore, it can also be used for observation of in-vivo tissues, so it can be applied in various ways depending on the purpose, such as near-infrared fluorescent probes, in pathological elucidation and diagnosis in the medical field. .

[Organic photoelectric conversion element]
Since the compound represented by the above formula (1) has near-infrared light absorption characteristics, it is expected to be used as an organic photoelectric conversion element. In particular, the compound represented by the above formula (1) can be used in the photoelectric conversion layer in the organic photoelectric conversion element of the present invention. In this element, it is preferable that the maximum absorption of the absorption band of response wavelength light to light is 700 to 2500 nm. Here, examples of the organic photoelectric conversion element include a near-infrared light sensor, an organic image sensor, a near-infrared light image sensor, and the like.
In this specification, the maximum absorption of an absorption band means the maximum absorbance value in the absorbance spectrum measured by absorption spectrum measurement, and the maximum absorption wavelength (λmax) is the maximum absorption value on the longest wavelength side among the maximum absorptions. It means the wavelength at which maximum absorption occurs.

An organic photoelectric conversion element is an element in which a photoelectric conversion part (film) is arranged between a pair of electrode films facing each other, and light is incident on the photoelectric conversion part from above the electrode film. The photoelectric conversion unit has a function of generating electrons and holes according to the incident light, and an organic photoelectric conversion element including such a photoelectric conversion unit has a semiconductor that reads out a signal corresponding to the charge, and This is an element that shows the amount of incident light according to the absorption wavelength of the photoelectric conversion film portion. 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, the organic photoelectric conversion elements serve as imaging elements because they indicate not only the amount of incident light but also incident position information. In addition, if a photoelectric conversion element placed closer to the light source does not block (transmits) the absorption wavelength of a photoelectric conversion element placed behind it when viewed from the light source side, multiple photoelectric conversion elements may be stacked. May be used.

The organic photoelectric conversion element of the present invention uses the compound represented by the above formula (1) as a constituent material of the photoelectric conversion section.
The photoelectric conversion section includes a photoelectric conversion layer, and one or more types selected from the group consisting of an electron transport layer, a hole transport layer, an electron block layer, a hole block layer, a crystallization prevention layer, an interlayer contact improving layer, etc. It often consists of an organic thin film layer other than the photoelectric conversion layer. Although the compound of formula (1) above can be used for purposes other than the photoelectric conversion layer, it is preferably used as a material for the organic semiconductor film of the photoelectric conversion layer. The photoelectric conversion layer may be composed only of the compound represented by the above formula (1), but may contain a known near-infrared light absorbing material or others in addition to the compound represented by the above formula (1). You can stay there.

In the electrode film used in the organic photoelectric conversion element of the present invention, the photoelectric conversion layer included in the photoelectric conversion part described below has a hole transporting property, or the organic thin film layer other than the photoelectric converting layer has a hole transporting property. If it is a hole transport layer, it plays the role of extracting and collecting holes from the photoelectric conversion layer and other organic thin film layers, and the photoelectric conversion layer included in the photoelectric conversion part has electron transport properties. or when the organic thin film layer other than the photoelectric conversion layer is an electron transport layer having electron transporting properties, it plays the role of extracting electrons from the photoelectric conversion layer and other organic thin film layers and discharging them. be. 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, but it does not have to be limited in particular to adhesion to the adjacent photoelectric conversion layer or other organic thin film layer, electron affinity, ionization potential, stability, etc. It is preferable to take this into consideration when making a selection. Examples of materials that can be used as the electrode film 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 used as a mixture if necessary, or two or more layers of electrode films made of different materials may be laminated. The conductivity of the material used for the electrode film is also not particularly limited as long as it does not unduly impede light reception by the photoelectric conversion element, but it is preferably as high as possible from the viewpoint of signal strength and power consumption of the photoelectric conversion element. For example, a conductive ITO film with a sheet resistance value of 300 Ω/□ or less can function satisfactorily as an electrode film, but commercially available substrates with ITO films having a conductivity of several Ω/□ are also available. Therefore, it is desirable to use a substrate having such high conductivity. The thickness of the ITO film (electrode film) can be arbitrarily selected in consideration of conductivity, but is usually about 5 to 500 nm, preferably about 10 to 300 nm. Examples of methods for forming a film such as ITO include conventionally known vapor deposition methods, electron beam methods, sputtering methods, chemical reaction methods, and coating methods. The ITO film provided on the substrate may be subjected to UV-ozone treatment, plasma treatment, etc., if necessary.

Among the electrode films, materials for the transparent electrode film used on at least one of the light incident sides include ITO, IZO, SnO ₂ , ATO (antimony-doped tin oxide), ZnO, and AZO (Al-doped zinc oxide). , GZO (gallium-doped zinc oxide), TiO ₂ , FTO (fluorine-doped tin oxide), and the like. 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 even more preferably 95% or more. .

When stacking multiple photoelectric conversion layers that detect different wavelengths, the electrode film used between each photoelectric conversion layer (this is an electrode film other than the pair of electrode films described above) is such that each photoelectric conversion layer It is necessary to transmit light other than the light having the wavelength to be detected, and it is preferable to use a material that transmits 90% or more of the incident light, and preferably a material that transmits 95% or more of the incident light. More preferred.

It is preferable that the electrode film be produced without plasma. By producing 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 plasma is not used when forming the electrode film, or that the distance between the plasma generation source and the substrate is 2 cm or more, preferably 10 cm or more, and more preferably 20 cm or more so that the plasma can reach the substrate. This means a state in which the amount of plasma generated is reduced.

Examples of devices that can form electrode films without using plasma include electron beam evaporation devices (EB evaporation devices) and pulsed laser evaporation devices. A method of forming a transparent electrode film using an EB evaporation apparatus is referred to as an EB evaporation method, and a method of forming a transparent electrode film using a pulsed laser evaporation apparatus is referred to as a pulsed laser evaporation method.

Examples of devices that can reduce plasma during film formation include facing target sputtering devices and arc plasma deposition devices.

When a transparent conductive film is used as an electrode film (for example, a first conductive film), a DC short or an increase in leakage current may occur. One of the reasons for this is that fine cracks that occur in the photoelectric conversion layer are covered with a dense film such as TCO (Transparent Conductive Oxide), and the electrode film (second conductive film) on the opposite side of the first conductive film ) is thought to be due to increased conduction between the two. Therefore, when a material such as Al, which has a relatively inferior film quality, is used for the electrode, an increase in leakage current is unlikely to occur. By controlling the thickness of the electrode film according to the thickness of the photoelectric conversion layer (depth of cracks), it is possible to suppress an increase in leakage current.

Normally, when a conductive film is made thinner than a predetermined thickness, a rapid increase in resistance value occurs. The sheet resistance of the conductive film in the photoelectric conversion element for an optical sensor, which is one of the embodiments, is usually 100 to 10,000 Ω/□, and the film thickness can be set as appropriate. Additionally, the thinner the transparent conductive film is, the less light it absorbs, and generally the higher the light transmittance. A high light transmittance is very preferable because the amount of light absorbed by the photoelectric conversion layer increases and the photoelectric conversion ability improves.

The photoelectric conversion section included in the organic photoelectric conversion element of the present invention may consist of only a photoelectric conversion layer, or may include 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 section, but the organic semiconductor film may be one layer or multiple layers, and in the case of one layer, a p-type organic semiconductor film, an n-type organic semiconductor film, type organic semiconductor film, or a mixed film thereof (bulk heterostructure). On the other hand, in the case of multiple layers, the number of layers is about 2 to 10, and the structure is a stack of p-type organic semiconductor films, n-type organic semiconductor films, or mixed films thereof (bulk heterostructure). A buffer layer may be inserted between the layers. In addition, when forming a photoelectric conversion layer with the above mixed film, the compound represented by the formula (1) of the present invention is used as a p-type semiconductor material, and the general fullerene or its derivative is used as an n-type semiconductor material. It is preferable to use

In the organic photoelectric conversion element of the present invention, the organic thin film layer other than the photoelectric conversion layer constituting the photoelectric conversion section is a layer other than the photoelectric conversion layer, such as an electron transport layer, a hole transport layer, an electron block layer, a hole block layer, etc. It is used as a layer, a crystallization prevention layer, an interlayer contact improvement layer, etc. 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 (hereinafter also referred to as a "carrier block layer"), even weak light energy can be achieved. This is preferable because an element that efficiently converts into an electric signal can be obtained.

In addition, among organic photoelectric conversion devices, organic imaging devices generally use a method that aims to improve performance by reducing dark current for the purpose of high contrast and power saving, so carrier blocks are incorporated into the layer structure. A layer-inserting approach is preferred. These carrier block layers are commonly used in the field of organic electronic devices, and play a role in controlling the reverse movement of holes or electrons in the constituent films of each device.

The electron transport layer plays the role of transporting electrons generated in the photoelectric conversion layer to the electrode film and 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 the role of transporting generated holes from the photoelectric conversion layer to the electrode film and blocking electrons from moving from the electrode film to which the holes are transported to the photoelectric conversion layer. The electron blocking layer serves to prevent electrons from moving from the electrode film to the photoelectric conversion layer, prevent recombination within the photoelectric conversion layer, and reduce dark current. The hole blocking layer serves to prevent holes from moving from the electrode film to the photoelectric conversion layer, prevent recombination within the photoelectric conversion layer, and reduce dark current.

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 embodiment shown in FIG. 1, 1 is an insulating part, 2 is one electrode film (upper electrode film), 3 is an electron blocking layer, 4 is a photoelectric conversion layer, 5 is a hole blocking layer, and 6 is the other electrode film. (lower electrode film) and 7 represent an insulating base material or another organic photoelectric conversion element, respectively. The readout transistor not shown in the figure only needs to be connected to the 2nd or 6th electrode film, and if the photoelectric conversion layer 4 is transparent, it should be connected to the side opposite to the side where light enters. It may be formed on the outside of the electrode film. Light may be incident on the organic photoelectric conversion element either from the top or the bottom, provided that the components other than the photoelectric conversion layer 4 do not extremely inhibit the incidence of light at the main absorption wavelength of the photoelectric conversion layer. It may be from.

[Organic EL element]
Next, the organic EL element will be explained.
Since the compound represented by formula (1) of the present invention has near-infrared emission characteristics, it is expected to be used in organic EL devices.

Organic EL devices have attracted attention because they can be used for applications such as solid-state, self-luminous, large-area color displays and lighting, and many developments have been made. Its structure has two layers, a light emitting layer and a charge transport layer, between opposing electrodes consisting of a cathode and an anode; an electron transport layer, a light emitting layer and a hole transport layer are stacked between the opposing electrodes. There are known structures having three layers, and those having three or more layers, and there are also known structures in which the light-emitting layer is a single layer.

Here, the hole transport layer has a function of injecting holes from the anode, transporting the holes to the light emitting layer, facilitating the injection of holes into the light emitting layer, and a function of blocking electrons. Further, the electron transport layer has a function of injecting electrons from the cathode, transporting the electrons to the light emitting layer, facilitating the injection of electrons into the light emitting layer, and a function of blocking holes. Furthermore, in the light-emitting layer, excitons are generated by recombination of the injected electrons and holes, and the energy emitted during the process of radiation deactivation of the excitons is detected as luminescence. Preferred embodiments of the organic EL device will be described below.

An organic EL element is an element in which one or more layers of organic thin films are formed between an anode and a cathode, and emits light using electrical energy.

An anode that can be used in an organic EL device is an electrode that has the function of injecting holes into a hole injection layer, a hole transport layer, and a light emitting layer. Generally, metal oxides, metals, alloys, conductive materials, etc. having a work function of 4.5 eV or more are suitable. Specifically, materials suitable for the anode of organic EL elements are not particularly limited, but include conductive metals such as tin oxide (NESA), indium oxide, indium tin oxide (ITO), and indium zinc oxide (IZO). Oxides, metals such as gold, silver, platinum, chromium, aluminum, 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. Can be mentioned. Among them, it is preferable to use ITO or NESA.

The anode may be made of a plurality of materials, if necessary, or may be composed of two or more layers of different materials. The resistance of the anode is not limited as long as sufficient current can be supplied for light emission of the device, but it is preferably low from the viewpoint of power consumption of the device. For example, an ITO substrate with a sheet resistance value of 300 Ω/□ or less can function as an element electrode, but it is also possible to supply a substrate with a sheet resistance of several Ω/□, so it is desirable to use a low-resistance product. The thickness of ITO can be arbitrarily selected according to the resistance value, but it is usually used between 5 and 500 nm, preferably between 10 and 300 nm. Examples of methods for forming a film such as ITO include a vapor deposition method, an electron beam method, a sputtering method, a chemical reaction method, and a coating method.

A cathode that can be used in an organic EL device is an electrode that has the function of injecting electrons into an electron injection layer, an electron transport layer, and a light emitting layer. Generally, metals and alloys with a small work function (approximately 4 eV or less) are suitable. Specifically, platinum, gold, silver, copper, iron, tin, zinc, aluminum, indium, chromium, lithium, sodium, potassium, calcium, and magnesium can be mentioned, but they increase electron injection efficiency and improve device characteristics. Lithium, sodium, potassium, calcium or magnesium are preferred for this purpose. As the alloy, an alloy containing these low work function metals with metals such as aluminum or silver, or an electrode having a structure in which these are laminated can be used. It is also possible to use an inorganic salt such as lithium fluoride in the laminated electrode. Furthermore, when emitted light is extracted to the cathode side instead of the anode side, the cathode may be a transparent electrode that can be formed into a film at a low temperature. Examples of the cathode film forming method include a vapor deposition method, an electron beam method, a sputtering method, a chemical reaction method, and a coating method, but the method is not particularly limited. The resistance of the cathode is not limited as long as sufficient current can be supplied for light emission of the device, but from the viewpoint of power consumption of the device, it is preferably low, and specifically, about several hundred to several Ω/□ is preferable. The thickness of the cathode is usually 5 to 500 nm, preferably 10 to 300 nm.

Protect the cathode with oxides such as titanium oxide, silicon nitride, silicon oxide, silicon nitride oxide, germanium oxide, nitrides, or mixtures thereof, polyvinyl alcohol, vinyl chloride, hydrocarbon polymers, fluorine polymers, etc. , barium oxide, phosphorus pentoxide, calcium oxide, and other dehydrating agents.

Furthermore, in order to extract light emission, it is generally preferable to fabricate electrodes on a substrate that has sufficient transparency in the emission wavelength region of the device. Examples of the transparent substrate include a glass substrate and a polymer substrate. Soda lime glass, alkali-free glass, quartz, etc. are used for the glass substrate. The substrate only needs to have a thickness sufficient to maintain mechanical and thermal strength, preferably 0.5 mm or more. Regarding the material of the glass, it is preferable to use a material with a small amount of ions eluted from the glass, such as alkali-free glass. As such, commercially available soda lime glass coated with a barrier coating such as SiO ₂ can also be used. Examples of the polymer substrate include polycarbonate, polypropylene, polyether sulfone, polyethylene terephthalate, and acrylic substrates.

The organic thin film of an organic EL element is formed in one or more layers between an anode and a cathode. By incorporating the compound represented by the above formula (1) into the organic thin film, an element that emits light using electrical energy can be obtained.

The "layers" formed by organic thin films include a hole transport layer, an electron transport layer, a hole transport light emitting layer, an electron transport light emitting layer, a hole blocking layer, an electron blocking layer, a hole injection layer, and an electron injection layer. It means a layer, a light-emitting layer, or a single layer that has the functions of these layers as shown in Structure Example 9 below. FIG. 2 shows one embodiment of the organic EL device. In FIG. 2, 1E is a substrate, 2E is an anode, 3E is a hole injection layer, 4E is a hole transport layer, 5E is a light emitting layer, 6E is an electron transport layer, and 7E is a cathode. In addition to such embodiments, the structure of the layer forming the organic thin film in the organic EL element may be any of the following structure examples 1) to 9).

Configuration example 1) Hole transport layer/electron transport light emitting layer.
2) Hole transport layer/emissive layer/electron transport layer.
3) Hole-transporting light-emitting layer/electron-transporting layer.
4) Hole transport layer/light emitting layer/hole blocking layer.
5) Hole transport layer/light emitting layer/hole blocking layer/electron transport layer.
6) Hole transporting light emitting layer/hole blocking layer/electron transporting layer.
7) In each of the combinations 1) to 6) above, a configuration in which a hole injection layer is provided before the hole transport layer or the hole transportable light emitting layer.
8) In each of the combinations 1) to 3) and 5) to 7), an electron injection layer is further provided before the electron transport layer or the electron transport light emitting layer.
9) A structure in which the materials used in the combinations 1) to 8) are mixed, and there is only one layer containing the mixed materials.
Note that 9) may be a single layer formed of a material generally referred to as a bipolar luminescent material; or a single layer containing a luminescent material and a hole-transporting material or an electron-transporting material may be provided. Generally, by forming a multilayer structure, charges, that is, holes and/or electrons, can be efficiently transported and these charges can be recombined. Furthermore, by suppressing charge quenching, it is possible to prevent a decrease in the stability of the device and improve the efficiency of light emission.

The hole injection layer and the hole transport layer are formed by laminating a single hole transport material or a mixture of two or more of the materials. As hole transport materials, N,N'-diphenyl-N,N'-di(3-methylphenyl)-4,4''-diphenyl-1,1'-diamine, N,N'-dinaphthyl-N , N'-diphenyl-4,4'-diphenyl-1,1'-diamine and other triphenylamines; bis(N-allylcarbazole) or bis(N-alkylcarbazole); pyrazoline derivatives, stilbene compounds, Heterocyclic compounds typified by hydrazone compounds, triazole derivatives, oxadiazole derivatives, and porphyrin derivatives; in polymer systems, polycarbonates, styrene derivatives, polyvinylcarbazole, polysilanes, etc. having the above monomers in their side chains are preferably used; The material is not particularly limited as long as it can form a thin film necessary for device fabrication, inject holes from the electrode, and transport holes. The hole injection layer provided between the hole transport layer and the anode to improve the hole injection property may be a phthalocyanine derivative, m-MTDATA (4,4',4''-tris[phenyl (m-tolyl) Examples of polymers include starburst amines such as ( ) amino] triphenylamine), polythiophenes such as PEDOT (poly(3,4-ethylenedioxythiophene)), and polyvinylcarbazole derivatives.

The electron transport layer is formed by laminating a single electron transport material or a mixture of two or more of the materials. As an electron transport material, it is necessary to efficiently transport electrons from a negative electrode between electrodes to which an electric field is applied. It is preferable that the electron transport material has high electron injection efficiency and efficiently transports the injected electrons. To this end, the electron transport material is required to have a high electron affinity, high electron mobility, excellent stability, and be less likely to generate trapping impurities during production and use. Substances that meet these conditions include quinolinol derivative metal complexes such as tris(8-quinolinolato)aluminum complexes, tropolone metal complexes, perylene derivatives, perinone derivatives, naphthalimide derivatives, naphthalic acid derivatives, oxazole derivatives, and oxadiazoles. Examples include, but are not limited to, derivatives such as thiazole derivatives, thiadiazole derivatives, triazole derivatives, bisstyryl derivatives, pyrazine derivatives, phenanthroline derivatives, benzoxazole derivatives, and quinoxaline derivatives. These electron transport materials can be used alone, but they may also be used in a stacked or mixed manner with different electron transport materials. Examples of the electron injection layer provided between the electron transport layer and the cathode to improve electron injection properties include metals such as cesium, lithium, and strontium, and lithium fluoride.

The hole-blocking layer is formed by stacking hole-blocking substances singly or in a mixture of two or more types. Preferred hole blocking substances include phenanthroline derivatives such as bathophenanthroline and bathocuproine, silole derivatives, quinolinol derivative metal complexes, oxadiazole derivatives, and oxazole derivatives. The hole-blocking substance is not particularly limited as long as it is a compound that can prevent holes from flowing out from the cathode side to the outside of the device and a decrease in luminous efficiency.

A light-emitting layer means an organic thin film that emits light, and can be said to be, for example, a hole transport layer, an electron transport layer, or a bipolar transport layer that has strong luminescence. The light-emitting layer may be formed of a light-emitting material (a host material, a dopant material, etc.), and may be a mixture of a host material and a dopant material or a host material alone. The host material and dopant material may each be one type, or may be a combination of a plurality of materials.

The dopant material may be contained entirely or partially in the host material. The dopant material may be layered or dispersed. Examples of the light emitting layer include the aforementioned hole transport layer and electron transport layer. Materials used for the light emitting layer include carbazole derivatives, anthracene derivatives, naphthalene derivatives, phenanthrene derivatives, phenylbutadiene derivatives, styryl derivatives, pyrene derivatives, perylene derivatives, quinoline derivatives, tetracene derivatives, perylene derivatives, quinacridone derivatives, coumarin derivatives, Examples include porphyrin derivatives and phosphorescent metal complexes (Ir complexes, Pt complexes, Eu complexes, etc.).

Methods for forming organic thin films for organic EL devices generally include vacuum processes such as resistance heating evaporation, electron beam evaporation, sputtering, and molecular lamination, and solution processes such as casting, spin coating, dip coating, blade coating, and wire bar coating. We employ coating methods such as coating and spray coating, printing methods such as inkjet printing, screen printing, offset printing, and letterpress printing, soft lithography methods such as microcontact printing, and methods that combine multiple of these methods. I can do it. The thickness of each layer is not limited as it depends on the resistance value and charge mobility of each material, but is selected from 0.5 to 5,000 nm. Preferably it is 1 to 1,000 nm, more preferably 5 to 500 nm.

Among the organic thin films constituting the organic EL element, one or more thin films such as a light emitting layer, a hole transport layer, an electron transport layer, etc., present between the anode and cathode electrodes have a compound represented by the above formula (1). By containing the compound, an element that efficiently emits light even with low electrical energy can be obtained.

The compound represented by the above formula (1) can be suitably used as a hole transport layer, a light emitting layer, or an electron transport layer. For example, it can be used in combination with or mixed with the above-mentioned electron transport material, hole transport material, luminescent material, etc.

Specific examples of dopant materials when the compound represented by formula (1) above is used as a host material in combination with a dopant material include perylene derivatives such as bis(diisopropylphenyl)perylenetetracarboxylic acid imide, perinone derivatives, 4- (dicyanomethylene)-2methyl-6-(p-dimethylaminostyryl)-4H pyran (DCM) and its analogs, metal phthalocyanine derivatives such as magnesium phthalocyanine and aluminum chlorophthalocyanine, rhodamine compounds, deazaflavin derivatives, coumarin derivatives, oxazine compounds, squarylium compounds, violanthrone compounds, Nile Red, pyrromethene derivatives such as 5-cyanopyromethene-BF ₄ complex, and phosphorescent materials such as Eu complexes with acetylacetone, benzoylacetone and phenanthroline as ligands, Ir complexes, Ru complexes, Porphyrins such as Pt complexes and Os complexes, orthometal metal complexes, and the like can be used, but are not particularly limited to these. Furthermore, when two types of dopant materials are mixed, it is also possible to use an assist dopant such as rubrene to efficiently transfer energy from the host dye to obtain light emission with improved color purity. In any case, in order to obtain high luminance characteristics, it is preferable to dope with a substance having a high fluorescence quantum yield.

If the amount of dopant material used is too large, a concentration quenching phenomenon will occur, so the amount is usually 30% by mass or less based on the host material. Preferably it is 20% by mass or less, more preferably 10% by mass or less. As a method of doping the host material with the dopant material in the light emitting layer, it can be formed by a co-evaporation method with the host material, but it may also be mixed with the host material in advance and then vapor-deposited at the same time. It is also possible to use it by sandwiching it between host materials. In this case, one or more dopant layers may be laminated with the host material.

These dopant layers may be formed using a dopant material alone or may be formed by mixing dopant materials. In addition, the dopant material can be used as a polymeric binder such as polyvinyl chloride, polycarbonate, polystyrene, polystyrene sulfonic acid, poly(N-vinylcarbazole), poly(methyl)(meth)acrylate, polybutyl methacrylate, polyester, polysulfone, Solvent-soluble resins such as polyphenylene oxide, polybutadiene, hydrocarbon resin, ketone resin, phenoxy resin, polysulfone, polyamide, ethyl cellulose, vinyl acetate, ABS resin (acrylonitrile-butadiene-styrene copolymer resin), polyurethane resin, phenol resin, It can also be used by dissolving or dispersing it in curable resins such as xylene resins, petroleum resins, urea resins, melamine resins, unsaturated polyester resins, alkyd resins, epoxy resins, and silicone resins.

Organic EL elements can be suitably used as flat panel displays. It can also be used as a flat backlight, and in this case, either one that emits colored light or one that emits white light can be used. Backlights are mainly used for the purpose of improving the visibility of display devices that do not emit light by themselves, and are used in liquid crystal display devices, watches, audio equipment, automobile panels, display boards, signs, etc. In particular, conventional backlights for personal computers, where liquid crystal display devices, especially thinner ones, are difficult to make thinner because they consist of fluorescent lamps and light guide plates. The backlight using the element is characterized by being thin and lightweight, so the above-mentioned problems can be solved. Similarly, it can be usefully used for lighting.

By using the compound represented by the above formula (1) of the present invention, an organic EL display device with high luminous efficiency and long life can be obtained. Furthermore, by combining thin film transistor elements, it becomes possible to provide at low cost an organic EL display device in which the on/off phenomenon of applied voltage is electrically controlled with high precision.

[Organic semiconductor laser device]
Since the compound represented by the above formula (1) has near-infrared emission characteristics, it is expected to be used as an organic semiconductor laser device. In other words, if an organic semiconductor laser element containing the compound represented by formula (1) above is combined with a resonator structure and the density of excited states can be sufficiently increased by efficiently injecting carriers, light can be amplified. It is expected that this will lead to laser oscillation. Conventionally, in organic semiconductor laser devices, only laser oscillation due to optical excitation has been observed, and it has been said that it is extremely difficult to generate the high-density excited state required for laser oscillation due to electrical excitation. However, by using an organic semiconductor element containing the compound represented by the above formula (1), it is expected that highly efficient light emission (electroluminescence) will occur.

The present invention will be explained in more detail with reference to Examples below, but the present invention is not limited to these Examples. The structures of the compounds described in the synthesis examples were determined by mass spectrometry (MS) and nuclear magnetic resonance spectroscopy (NMR) as necessary. In Examples, ¹ H-NMR spectra were measured using JNM-ECS400 (JEOL Ltd.), and MS spectra were measured using ISQTM 7000 single quadrupole GC-MS system (Thermo Fisher Scientific). The absorption spectrum was measured using an ultraviolet-visible spectrophotometer UV-1700 (Shimadzu Corporation). The current and voltage applied to the organic photoelectric conversion elements in the Examples and Comparative Examples were measured using a semiconductor parameter analyzer 4200-SCS (manufactured by Keithley Instruments). The incident light was irradiated using a PVL-3300 (manufactured by Asahi Bunko Co., Ltd.), and the measurement was carried out in the range of 350 nm to 1100 nm using a light source with an irradiation light intensity of 130 μW and a half-value width of 20 nm.

[Example 1]
In Example 1, the compound represented by the following formula (2-1) was synthesized using methyl 3-methoxy-2-thienothiophenecarboxylate as a raw material in a manner similar to that previously reported (for example, Tetrahedron Letters, 2008, 49, 3716-3721). The compound of the present invention represented by the following formula (1-1) was synthesized using the compound represented by the following formula (1-1) as a starting material according to the following synthesis flow.

(Step 1) Synthesis of intermediate compound represented by formula (2-2) In a flask, (1-acetyl-4-fluorophenyl)(3-methoxy-2 -Thienothienyl) methanone (32 mmol) was dissolved in ethanol (350 mL) and acetic acid (75 mL), heated to 65°C, added ammonium acetate (200 mmol) and ammonium chloride (35 mmol), and heated to 90°C for 3 hours. Stirred. The reaction solution was air-cooled and neutralized with a saturated aqueous sodium bicarbonate solution, and the resulting solid was collected by filtration to obtain an intermediate compound represented by formula (2-2) (8.4 mmol, yield rate: 53%).
The measurement results of the mass spectrometry spectrum of the intermediate compound represented by formula (2-2) were as follows.
EI-MS (m/z): 616 [M] ⁺

(Step 2) Synthesis of intermediate compound represented by formula (2-3) In a flask, put the compound represented by formula (2-2) obtained in step 1 (8.4 mmol), toluene (350 mL) and After adding triethylamine (84 mmol) and heating to 80°C, boron trifluoride diethyl ether complex (84 mmol) was added dropwise, the temperature was raised to 100°C, and the mixture was stirred overnight. The reaction solution was air-cooled and neutralized with a saturated aqueous sodium bicarbonate solution, and the resulting solid was collected by filtration to obtain an intermediate compound represented by formula (2-3) (3.0 mmol, yield rate: 36%).
The measurement results of nuclear magnetic resonance spectrum (NMR) of the intermediate compound represented by formula (2-3) were as follows.
1H-NMR (400MHz, CDCl ₃ ) δ (ppm) = 7.86 (q, 2H), 7.67 (s, 1H), 7.43 (d, 2H), 7.33 (dd, 2H), 7.24-7.22 (m, 2H), 7.21 (d, 2H), 3.96 (s, 6H)

(Step 3) Synthesis of compound 1 of the present invention represented by formula (1-1) In a flask, put the intermediate compound (1.8 mmol) represented by formula (2-3) obtained in step 2 and dichloromethane. (60 mL) was added and stirred, boron tribromide (9 mL) was added dropwise, and the mixture was stirred at room temperature for 5 hours. The precipitate generated by adding saturated sodium bicarbonate solution was collected by filtration and washed repeatedly with water and methanol to obtain a black compound 1 of the present invention represented by formula (1-1) (1.6 mmol, Yield: 89%).
The measurement results of the mass spectrometry spectrum and absorption spectrum of Compound 1 represented by formula (1-1) were as follows.
EI-MS (m/z): 596 [M] ⁺
λmax=845nm (chloroform)

[Example 2]
(Step 4) Synthesis of compound 2 of the present invention represented by the following formula (1-2) Instead of the compound represented by formula (2-1), (1-acetyl-4-fluorophenyl)(5- Compound 2 of the present invention represented by formula (1-2) was prepared according to Steps 1 to 3 of Example 1 except that (4-cyanophenyl)-3-methoxy-2-thienothienyl)methanone was used. (yield: 89%).
The measurement results of the mass spectrometry spectrum and absorption spectrum of the compound 2 of the present invention represented by formula (1-2) were as follows.
EI-MS (m/z): 798 [M] ⁺
λmax=890nm (chloroform)

[Example 3]
(Step 5) Synthesis of compound 3 of the present invention represented by the following formula (1-3) Instead of the compound represented by formula (2-1), (1-acetyl-4-fluorophenyl)(5- Compound 3 of the present invention represented by formula (1-3) was obtained according to Steps 1 to 3 of Example 1 except that (benzobisthiadiazole)-3-methoxy-2-thienothienyl)methanone was used. (Yield: 55%).
The measurement results of the mass spectrometry spectrum and absorption spectrum of the compound 3 of the present invention represented by formula (1-3) were as follows.
EI-MS (m/z): 864 [M] ⁺
λmax=900nm (chloroform)

[Example 4]
(Step 6) Synthesis of compound 4 of the present invention represented by the following formula (1-4) Instead of the compound represented by formula (2-1), (1-acetyl-3-phenyl)-4-fluoro The present invention represented by formula (1-4) was prepared according to Steps 1 to 3 of Example 1 except that phenyl)(5-(benzobisthiadiazole)-3-methoxy-2-thienothienyl)methanone was used. Compound 4 was obtained (yield: 30%).
The measurement results of the mass spectrometry spectrum and absorption spectrum of the compound 4 of the present invention represented by formula (1-4) were as follows.
EI-MS (m/z): 1016 [M] ⁺
λmax=913nm (chloroform)

[Comparative example 1]
Synthesis of Comparative Compound 1 Comparative Compound 1 represented by the following formula (3-1) was obtained according to the method described in Patent Document 2. The λmax of a chloroform solution of this compound was 790 nm.

[Comparative example 2]
Synthesis of Comparative Compound 2 Comparative Compound 2 represented by the following formula (3-2) was obtained according to the method described in Patent Document 6. The λmax of a chloroform solution of this compound was 769 nm.

Compounds 1 to 4 of the present invention obtained in Example 1, Example 2, Example 3, and Example 4 (Formula (1-1), (1-2), (1-3), (1-4) ) has a maximum absorption wavelength in solution in a longer wavelength region than Comparative Compounds 1 and 2 (compounds represented by formulas (3-1) and (3-2)). , it is clear that near-infrared light around 900 nm can be efficiently absorbed.

[Example 5]
Preparation of organic thin film 1 of the present invention and absorption spectrum measurement Compound 1 of the present invention represented by formula (1-1) obtained in Example 1 was deposited on a glass substrate by a resistance heating method under vacuum. Organic thin film 1 of the invention was obtained. As a result of measuring the absorption spectrum of the organic thin film 1 on the obtained glass substrate, λmax of the absorption spectrum was 870 nm.

[Example 6]
Preparation of organic thin film 2 of the present invention and absorption spectrum measurement In place of the compound 1 of the present invention represented by the formula (1-1) obtained in Example 1, the compound ) An organic thin film 2 of the present invention was obtained according to Example 5 except that Compound 2 of the present invention represented by formula 2 was used. As a result of measuring the absorption spectrum of the organic thin film 2 on the obtained glass substrate, λmax of the absorption spectrum was 905 nm.

[Example 7]
Preparation of Organic Thin Film 3 of the Present Invention and Absorption Spectrum Measurement Instead of the compound 1 of the present invention represented by the formula (1-1) obtained in Example 1, the compound 1 obtained in Example 3 was substituted with ) An organic thin film 3 of the present invention was obtained in accordance with Example 5 except that Compound 3 of the present invention represented by formula 3 was used. As a result of measuring the absorption spectrum of the organic thin film 3 on the obtained glass substrate, λmax of the absorption spectrum was 960 nm.

[Example 8]
Preparation of Organic Thin Film 4 of the Present Invention and Absorption Spectral Measurement Instead of the compound 1 of the present invention represented by the formula (1-1) obtained in Example 1, the compound 1 obtained in Example 4 was substituted with ) An organic thin film 3 of the present invention was obtained in accordance with Example 5 except that Compound 3 of the present invention represented by formula 3 was used. As a result of measuring the absorption spectrum of the organic thin film 3 on the obtained glass substrate, λmax of the absorption spectrum was 984 nm.

[Comparative example 3]
Preparation of organic thin film 1 for comparison and absorption spectrum measurement Instead of compound 1 of the present invention represented by formula (1-1) obtained in Example 1, formula (3-1) obtained in Comparative Example 1 was used. Comparative organic thin film 1 was obtained according to Example 5 except that Comparative Compound 1 represented by was used. As a result of measuring the absorption spectrum of the organic thin film 1 for comparison on the obtained glass substrate, λmax of the absorption spectrum was 760 nm.

[Comparative example 4]
Preparation of comparative organic thin film 2 and absorption spectrum measurement Instead of compound 1 of the present invention represented by formula (1-1) obtained in Example 1, formula (3-2) obtained in Comparative Example 2 was used. Comparative organic thin film 2 was obtained according to Example 5 except that Comparative Compound 2 represented by was used. As a result of measuring the absorption spectrum of the organic thin film 2 for comparison on the obtained glass substrate, λmax of the absorption spectrum was 810 nm.

From the results of Examples 5, 6, 7, and 8 and Comparative Examples 3 and 4, the organic thin films of Examples containing the compounds of the present invention have λmax on the longer wavelength side than the organic thin films of Comparative Examples, and even in thin films. It is clear that near-infrared light around 900 nm can be absorbed more efficiently.

[Example 9]
Preparation and Evaluation of Organic Photoelectric Conversion Element 1 Containing the Organic Thin Film of the Present Invention The formula (1-1) obtained in Example 1 was applied on a pre-cleaned ITO transparent conductive glass (manufactured by Geomatec, ITO film thickness 150 nm). Compound 1 of the present invention shown below was vacuum deposited using resistance heating to form an organic thin film with a thickness of 100 nm. Next, an electrode having a thickness of 100 nm was formed on the obtained organic thin film by resistance heating vacuum evaporation of aluminum, thereby producing an organic photoelectric conversion element 1 of the present invention. Using ITO and aluminum as electrodes, the photocurrent response was measured when a voltage of 1 V was applied under irradiation with light of 350 nm to 1100 nm, and the maximum photocurrent wavelength was 906 nm.

[Example 10]
Preparation and Evaluation of Organic Photoelectric Conversion Element 2 Containing the Organic Thin Film of the Present Invention The formula (1-2) obtained in Example 2 was applied on a pre-cleaned ITO transparent conductive glass (manufactured by Geomatec, ITO film thickness 150 nm). Compound 2 of the present invention shown below was vacuum deposited using resistance heating to form an organic thin film with a thickness of 100 nm. Next, an electrode having a thickness of 100 nm was formed on the obtained organic thin film by resistance heating vacuum evaporation of aluminum, thereby producing an organic photoelectric conversion element 2 of the present invention. Using ITO and aluminum as electrodes, the photocurrent response was measured when a voltage of 1 V was applied under irradiation with light of 350 nm to 1100 nm, and the maximum photocurrent wavelength was 981 nm.

[Example 11]
Preparation and Evaluation of Organic Photoelectric Conversion Element 3 Containing the Organic Thin Film of the Present Invention The formula (1-3) obtained in Example 3 was applied on a pre-cleaned ITO transparent conductive glass (manufactured by Geomatec, ITO film thickness 150 nm). Compound 3 of the present invention shown below was vacuum deposited using resistance heating to form an organic thin film with a thickness of 100 nm. Next, an electrode having a thickness of 100 nm was formed on the obtained organic thin film by resistance heating vacuum evaporation of aluminum, thereby producing an organic photoelectric conversion element 3 of the present invention. Using ITO and aluminum as electrodes, the photocurrent response was measured when a voltage of 1 V was applied while irradiating light from 350 nm to 1100 nm, and the maximum photocurrent wavelength was 990 nm.

[Comparative example 5]
Preparation and evaluation of comparative organic photoelectric conversion element 1 including comparative organic thin film Comparative compound 1 represented by formula (3-1) was used instead of compound 1 represented by formula (1-1) Comparative organic photoelectric change element 1 was produced in accordance with Example 9 except for that, and the photocurrent responsiveness was measured. Using ITO and aluminum as electrodes, the photocurrent response was measured when a voltage of 1 V was applied while irradiating light from 350 nm to 1100 nm, and the maximum photocurrent wavelength was 772 nm.

[Comparative example 6]
Preparation and evaluation of comparative organic photoelectric conversion element 2 including comparative organic thin film Comparative compound 2 represented by formula (3-2) was used instead of compound 1 represented by formula (1-1). Comparative organic photoelectric change element 2 was produced in accordance with Example 9 except for that, and the photocurrent responsiveness was measured. Using ITO and aluminum as electrodes, the photocurrent response was measured when a voltage of 1 V was applied while irradiating light from 350 nm to 1100 nm, and the maximum photocurrent wavelength was 824 nm.

Evaluation of brightness ratio of organic photoelectric conversion element including organic thin film of the present invention Using organic photoelectric conversion elements 1, 2, and 3 of the present invention obtained in Examples 9 to 11, under the same conditions as Examples 9 to 11, The photocurrent value (A/cm ² ) and dark current value (A/cm ² ) were measured by light irradiation and applied voltage, and the brightness/darkness ratio at 900 nm and 1000 nm was calculated. The results are shown in Table 1.

Evaluation of brightness ratio of organic photoelectric conversion element including comparative organic thin film Using comparative organic photoelectric conversion elements 1 and 2 obtained in Comparative Examples 5 and 6, light irradiation and application under the same conditions as Comparative Examples 5 and 6 were performed. The photocurrent value (A/cm ² ) and dark current value (A/cm ² ) were measured using voltage, and the brightness/darkness ratio at 900 nm and 1000 nm was calculated. The results are shown in Table 1.

From the above results, the organic photoelectric conversion device of the example containing the organic thin film of the compound of the present invention showed a maximum photocurrent wavelength on the longer wavelength side than the organic photoelectric conversion device of the comparative example, and emitted near-infrared light of 900 nm or more. It is clear that it can be absorbed. Furthermore, the organic photoelectric conversion device containing the organic thin film of the present invention exhibits a high contrast ratio for light in the near-infrared region, and the compound of the present invention is found to be effective as a material for image pickup devices and optical sensors. Understood.

It was found that it has a high contrast ratio even in the near-infrared region, making it effective as a material for image sensors.

The compound of the present invention, which has a main absorption band in the near-infrared region, is easy to synthesize and has both absorption properties in the near-infrared region and properties that can be deposited, so it is suitable for organic electronics that operate in the near-infrared region. Very useful as a device material.

(Figure 1)
1 Insulating part 2 Upper electrode film 3 Electron blocking layer 4 Photoelectric conversion layer 5 Hole blocking layer 6 Lower electrode film 7 Insulating base material or other photoelectric conversion element

(Figure 2)
1E Substrate 2E Anode 3E Hole injection layer 4E Hole transport layer 5E Light emitting layer 6E Electron transport layer 7E Cathode

Claims (13)

The following formula (1)

(In formula (1), R ₁ to R ₈ may each independently have a hydrogen atom, an unsubstituted aliphatic hydrocarbon group, an unsubstituted alkoxy group, an unsubstituted alkylthio group, or a substituent. Represents an aromatic group, an unsubstituted heterocyclic group, a halogen atom, a hydroxyl group, a mercapto group, a nitro group, an unsubstituted amino group, a cyano group, a sulfo group, or an unsubstituted acyl group. Optional substituents are selected from alkyl groups having 1 to 4 carbon atoms, halogen atoms, and phenyl groups.However, at least one of R ₁ to R ₄ represents a group other than a hydrogen atom, and R ₅ to R ₈ At least one represents an atom other than hydrogen.
R ₉ to R ₁₂ each independently represent a hydrogen atom, an unsubstituted aliphatic hydrocarbon group, an unsubstituted alkoxy group, an unsubstituted alkylthio group, an aromatic group represented by the following formula (2) , an unsubstituted Represents a heterocyclic group, a halogen atom, a hydroxyl group, a mercapto group, a nitro group, an unsubstituted amino group, a cyano group, a sulfo group, or an unsubstituted acyl group.

(In formula (2), R ₂₁ to R ₂₅ each independently represent a hydrogen atom, an unsubstituted alkoxy group, an unsubstituted alkylthio group, an aromatic group which may have a substituent, an unsubstituted heterocyclic ring) group, an unsubstituted amino group, or an electron-accepting substituent or atom, and the substituent that the aromatic group may have is selected from an alkyl group having 1 to 4 carbon atoms, a halogen atom, and a phenyl group. .R ₂₁ and R ₂₂ may be combined, or R ₂₂ and R ₂₃ may be combined to form an aromatic ring or a heterocycle.However, at least one of R ₂₁ to R ₂₅ is electron-accepting . or R ₂₁ and R ₂₂ combine, or R ₂₂ and R ₂₃ combine to form an electron-accepting aromatic ring or heterocycle.) . At least one of R ₁ to R ₄ is an aliphatic hydrocarbon group, aromatic group, heterocyclic group, or halogen atom, and at least one of R ₅ to R ₈ is an aliphatic hydrocarbon group, aromatic group, or heterocyclic group. The compound according to claim 1, which is a ring group or a halogen atom. The compound according to claim 2, wherein at least one of R ₁ to R ₄ is a halogen atom, and at least one of R ₅ to R ₈ is a halogen atom. 3. The compound according to claim 2, wherein at least one of R ₁ to R ₄ is an aromatic group or a heterocyclic group, and at least one of R ₅ to R ₈ is an aromatic group or a heterocyclic group. Any of claims 1 to 4, wherein R ₁ and R ₈ are the same, R ₂ and R ₇ are the same, R ₃ and R ₆ are the same, and R ₄ and R ₅ are the same. The compound according to item 1. 6. At least one of R ₉ and R ₁₀ is an aromatic group or a heterocyclic group, and at least one of R ₁₁ and R ₁₂ is an aromatic group or a heterocyclic group. Compounds described. 7. The compound according to claim 6, wherein _R9 and _R12 are hydrogen atoms, and _R10 and _R11 are aromatic groups or heterocyclic groups. At least one of R ₂₁ to R ₂₅ is a halogen atom, a formyl group, an acetyl group, an alkoxycarbonyl group, a trifluoromethyl group, a cyano group, a nitro group, a toluenesulfonyl group, a methanesulfonyl group, a trifluoromethanesulfonyl group, a pyridyl group, A claim that the electron-accepting substituent or atom is selected from the group consisting of a quinolyl group, a pyrazyl group, a quinoxalyl group, a thiazolyl group, a benzothiazolyl group, an indolyl group, a benzothiadiazolyl group, a succinimidoyl group, and a phthalimidoyl group. The compound described in 1 . 2. The compound according to claim 1 , wherein _R21 and _R22 are combined, or _R22 and _R23 are combined to form a heterocycle containing a nitrogen atom and/or a sulfur atom. A near-infrared light absorbing material comprising the compound according to any one of claims 1 to 9 . An organic thin film comprising the near-infrared light absorbing material according to claim 10 . An organic electronic device comprising the organic thin film according to claim 11 . An organic photoelectric conversion element comprising the organic thin film according to claim 11 .