Compound, composition, film, photoelectric conversion element, and CMOS image sensor

Abstract

To provide a compound that enables shifting of the absorption wavelength to a longer wavelength while maintaining light absorption properties in A-D-A type non-fullerene acceptor materials, and to provide a composition, a film, a photoelectric conversion element, and a CMOS image sensor, each made using the compound.SOLUTION: The present invention provides a compound represented by the following general formula (1). In the formula, X1 to X4 are each independently a hydrogen atom, a chlorine atom, a fluorine atom, a bromine atom, or a cyano group, Y1 to Y4 are each independently a hydrogen atom, an alkyl group, an alkoxy group, or an ester group, Z1 and Z2 are each independently an oxygen atom or a dicyanomethylene group, and M is a carbon atom substituted with an alkyl group or an aryl group, a silicon atom substituted with an alkyl group or an aryl group, or a germanium atom substituted with an alkyl group or an aryl group.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a compound, a composition, a film, a photoelectric conversion element, and a CMOS image sensor suitable as a semiconductor material used for a photoelectric conversion element.

Background Art

[0002] A CMOS image sensor equipped with a photoelectric conversion element is used, for example, as an imaging element of a digital camera or a smartphone. CMOS image sensors include inorganic CMOS image sensors and organic CMOS image sensors, and inorganic CMOS image sensors using silicon photodiodes are generally used. On the other hand, an organic CMOS image sensor can achieve both high resolution and a wide dynamic range by taking advantage of the high light absorption ability of an organic thin film, and can also be equipped with a global shutter that is less likely to distort an image. Thus, it is said that an organic CMOS image sensor can solve the problem of achieving both a high dynamic range and a global shutter, which are difficult for an inorganic CMOS image sensor. Therefore, a material suitable for an organic CMOS image sensor is required.

[0003] In addition, in a photoelectric conversion element (hereinafter also referred to as an "inorganic photoelectric conversion element") provided in an inorganic CMOS image sensor, generally, a cheap silicon semiconductor is used for the light response with an absorption wavelength up to 1000 nm, but when the absorption wavelength exceeds 1000 nm, a very expensive indium gallium arsenide (InGaAs) semiconductor is used. Therefore, a semiconductor material that is inexpensive and can be used in the long wavelength region is required, and an organic semiconductor material (hereinafter also referred to as an "organic semiconductor material") has attracted attention as a candidate.

[0004] In an organic CMOS image sensor, in a photoelectric conversion element (hereinafter also referred to as an "organic photoelectric conversion element") provided therein, the photoelectric conversion ability and the absorption wavelength range can be controlled by the molecular design of a p-type semiconductor material and an n-type semiconductor material used in an organic thin film (photoelectric conversion layer) constituting the photoelectric conversion element. In recent years, high photoconversion ability has been reported in elements using a non-fullerene acceptor as an n-type semiconductor material. In a photoelectric conversion element using a non-fullerene acceptor, the role of controlling the absorption wavelength range is mainly played by the n-type semiconductor material. As the n-type semiconductor material (light absorption material and electron transport material), a compound having an electron acceptor (A) part and an electron donor (D) part, a so-called A-D-A type compound (hereinafter also referred to as an "A-D-A type non-fullerene acceptor material") is known. The design of the absorption wavelength in an A-D-A type compound is possible by reducing the HOMO-LUMO gap by selecting the electron-withdrawing property of the A part and the electron-donating property of the D part.

[0005] As the A-D-A type compound, a compound having cyclopentadithiophene as a central donor (D) part and thiophene rings (D 1 ) and (D 2 ) sandwiching the D part, an A-D 1 -D-D 2 -A type compound is known. For example, Non-Patent Document 1 discloses a compound represented by the following formula (a) which is an A-D'-D-D'-A type compound, a compound represented by the following formula (b) which is an A-D'-D-D''-A type compound, and a compound represented by the following formula (c) which is an A-D''-D-D''-A type compound. Here, D' represents a thiophene ring substituted with an alkoxy group, and D'' represents a thiophene ring substituted with an alkyl group. According to Non-Patent Document 1, the compound represented by the following formula (a) can achieve the longest absorption wavelength. The compound represented by the following formula (a) is a compound obtained by substituting the alkyl group bonded to the thiophene ring in the D'' part of the compound represented by the following formula (b) or the following formula (c) with an alkoxy group which is a strong electron-donating group to form a D' part.

[0006]

Chemical formula

Prior Art Documents

Non-Patent Documents

[0007]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0008] By the way, in A-D-A type non-fullerene acceptor materials, in order to shift the absorption wavelength to a longer wavelength, a molecular design guideline for enhancing the electron-donating property of the D part or the electron-withdrawing property of the A part is known. However, if the electron-donating property of the D part or the electron-withdrawing property of the A part is enhanced too much, the excitation of intramolecular charge mobility becomes dominant, and the light absorption property may decrease. Since the decrease in the light absorption property leads to a decrease in the photoelectric conversion characteristics, in A-D-A type compounds used in photoelectric conversion elements, a molecular design for shifting the absorption wavelength to a longer wavelength while maintaining the light absorption property and being able to enhance the electron-donating property of the D part or the electron-withdrawing property of the A part is required.

[0009] An object of the present invention is to provide a compound capable of shifting the absorption wavelength to a longer wavelength while maintaining the light absorption property in an A-D-A type non-fullerene acceptor material, and a composition, a film, a photoelectric conversion element, and a CMOS image sensor using this compound.

Means for Solving the Problems

[0010] In view of the above problems, the present inventors have studied compounds that can extend the absorption wavelength while maintaining the light absorption properties in A-D-A type non-fullerene acceptor materials. Specifically, the ring structure of part A was studied. As a result, it was found that by including a specific pyrazine ring structure in part A, the absorption wavelength can be extended while maintaining the light absorption properties, leading to the completion of the present invention.

[0011] That is, the present invention has the following aspects. [1] A compound represented by the following general formula (1).

[0012] [Chemical formula]

[0013] In the general formula (1), X 1 ~X 4 are each independently a hydrogen atom, a chlorine atom, a fluorine atom, a bromine atom or a cyano group, Y 1 ~Y 4 are each independently a hydrogen atom, an alkyl group, an alkoxy group or an ester group, Z 1 and Z 2 are each independently an oxygen atom or a dicyanomethylene group, and M is a carbon atom substituted with an alkyl group or an aryl group, a silicon atom substituted with an alkyl group or an aryl group, or a germanium atom substituted with an alkyl group or an aryl group.

[0014] [2] The compound according to [1] above, wherein Z 1 and Z 2 in the general formula (1) are dicyanomethylene groups. [3] The compound according to [1] or [2] above, wherein X 1 ~X 4 in the general formula (1) are the same and are a hydrogen atom, a chlorine atom, a fluorine atom or a cyano group. [4] The compound according to any one of [1] to [3] above, wherein M in the general formula (1) is a carbon atom substituted with an alkyl group or an aryl group or a silicon atom substituted with an alkyl group or an aryl group. [5] Y in the general formula (1) 1 and Y 3 One of them is a hydrogen atom, and the other is an alkyl group, an alkoxy group or an ester group. A compound according to any one of [1] to [4] above, wherein one of Y 2 and Y 4 is a hydrogen atom, and the other is an alkyl group, an alkoxy group or an ester group. [6] Y in the general formula (1) 1 and Y 2 are each independently an alkyl group, an alkoxy group or an ester group, and a compound according to any one of [1] to [5] above, wherein Y 3 and Y 4 are hydrogen atoms. [7] Y in the general formula (1) 1 and Y 4 are each independently an alkyl group, an alkoxy group or an ester group, and a compound according to any one of [1] to [5] above, wherein Y 2 and Y 3 are hydrogen atoms. [8] X in the general formula (1) 1 ~X 4 are the same and are a chlorine atom, a fluorine atom or a cyano group, Y 1 and Y 2 are the same and are an alkoxy group, Y 3 and Y 4 are hydrogen atoms, Z 1 and Z 2 are a dicyanomethylene group, and M is a carbon atom substituted with an alkyl group or an aryl group. A compound according to any one of [1] to [6] above. [9] A composition containing a compound according to any one of [1] to [8] above.

[10] A film containing a compound according to any one of [1] to [8] above.

[11] A photoelectric conversion element provided with the film of

[10] above.

[12] A CMOS image sensor provided with the photoelectric conversion element of

[11] above.

Advantages of the Invention

[0015] According to the present invention, in an A-D-A type non-fullerene acceptor material, a compound capable of increasing the absorption wavelength while maintaining light absorption properties, a composition, a film, a photoelectric conversion element, and a CMOS image sensor using this compound can be provided.

Brief Description of the Drawings

[0016]

Figure 1

Modes for Carrying Out the Invention

[0017] Preferred embodiments of the invention are given below to explain the present invention in more detail. However, the following description is an example of an embodiment of the present invention, and the present invention is not limited to the following description as long as it does not exceed the gist of the invention. In this specification, "~" indicating a numerical range means including the numerical values described before and after it as the lower limit value and the upper limit value.

[0018] [Compound] The compound of the present invention is a compound represented by the following general formula (1) (hereinafter, also referred to as "compound (1)". The same applies hereinafter.).

[0019]

Chemical formula

[0020] In general formula (1), X 1 ~X 4 are each independently a hydrogen atom, a chlorine atom, a fluorine atom, a bromine atom, or a cyano group, and Y 1 ~Y 4 are each independently a hydrogen atom, an alkyl group, an alkoxy group, or an ester group, and Z 1 and Z 2is independently an oxygen atom or a dicyanomethylene group, and M is a carbon atom substituted with an alkyl group or an aryl group, a silicon atom substituted with an alkyl group or an aryl group, or a germanium atom substituted with an alkyl group or an aryl group.

[0021] Since the A part of the A-D-A type non-fullerene acceptor material of the compound of the present invention contains a specific pyrazine ring structure, while maintaining light absorbency, the absorption wavelength can be extended to a longer wavelength.

[0022] The reason why the compound of the present invention can extend the absorption wavelength while maintaining light absorbency is not clear, but it is presumed as follows. The compound of the present invention has an A part of an A-D-A type non-fullerene acceptor material containing a specific pyrazine ring structure. Compared with a conventional A-D-A type non-fullerene acceptor material in which the A part contains a benzene ring structure, the pyrazine ring is an electron-deficient aromatic ring, and furthermore, due to its low aromaticity, in addition to the enhanced electron-withdrawing property, it is easy to adopt a quinoid-like structure up to the ends of the molecule. Therefore, it is presumed that it enables both the extension of the absorption wavelength and the maintenance of light absorbency. Therefore, it is considered that the compound of the present invention can achieve both the extension of the absorption wavelength and the maintenance of light absorbency.

[0023] In the general formula (1), X 1 ~X 4 are each independently a hydrogen atom, a chlorine atom, a fluorine atom, a bromine atom, or a cyano group. It is considered that in compound (1), X 1 ~X 4 being a hydrogen atom, a chlorine atom, a fluorine atom, a bromine atom, or a cyano group can more effectively maintain and improve the electron-withdrawing property of the A part. X 1 ~X 4 may be the same or different, but it is preferably the same. X 1 ~X 4are the same and are preferably a hydrogen atom, a chlorine atom, a fluorine atom or a cyano group. Among them, in particular, in terms of further promoting the dense packing structure of the compounds, X 1 ~X 4 is preferably a cyano group. In terms of solubility, X 1 ~X 4 is preferably a chlorine atom or a fluorine atom.

[0024] In the general formula (1), Y 1 ~Y 4 are each independently a hydrogen atom, an alkyl group, an alkoxy group or an ester group. Y 1 ~Y 4 The number of carbon atoms of the alkyl group of is preferably small in terms of the conductivity of the material. Therefore, the number of carbon atoms of the alkyl group of Y 1 ~Y 4 is preferably 30 or less, more preferably 20 or less, still more preferably 15 or less, and particularly preferably 10 or less. Also, the number of carbon atoms of the alkyl group of Y 1 ~Y 4 is preferably 2 or more, more preferably 4 or more, still more preferably 6 or more, and particularly preferably 8 or more. Y 1 ~Y 4 The alkyl group of may be linear or cyclic. When the alkyl group is linear, it may be straight-chain or branched-chain. In terms of ease of synthesis, it is preferably a straight-chain or branched-chain alkyl group in which the carbon atom bonded to the thiophene ring is a primary carbon atom. In terms of the solubility of the material, it is preferably a branched-chain alkyl group in which the carbon atom bonded to the thiophene ring is a primary carbon atom, or a straight-chain, branched-chain or cyclic alkyl group in which the carbon atom bonded to the thiophene ring is a secondary carbon atom. From the viewpoints of ease of synthesis and solubility, it is more preferably a branched-chain alkyl group in which the carbon atom bonded to the thiophene ring is a primary carbon atom.

[0025] Y 1 ~Y 4The number of carbon atoms in the alkoxy group is preferably small in terms of the conductivity of the material. Therefore, Y 1 ~Y 4 The number of carbon atoms in the alkoxy group is preferably 30 or less, more preferably 20 or less, still more preferably 15 or less, and particularly preferably 10 or less. Also, Y 1 ~Y 4 The number of carbon atoms in the alkoxy group is preferably 2 or more, more preferably 4 or more, still more preferably 6 or more, and particularly preferably 8 or more. The alkoxy group has a structure in which an alkyl group is bonded to an oxygen atom. The alkyl group bonded to the oxygen atom may be linear or cyclic. When the alkyl group bonded to the oxygen atom is linear, it may be straight-chain or branched-chain. From the viewpoint of ease of synthesis, it is preferably a straight-chain or branched-chain alkyl group in which the carbon atom bonded to the oxygen atom is a primary carbon atom. From the viewpoint of the solubility of the material, it is preferably a branched-chain alkyl group in which the carbon atom bonded to the oxygen atom is a primary carbon atom, or a straight-chain, branched-chain or cyclic alkyl group in which the carbon atom bonded to the oxygen atom is a secondary carbon atom. More preferably, it is a straight-chain, branched-chain or cyclic alkyl group in which the carbon atom bonded to the oxygen atom is a secondary carbon atom, and still more preferably, it is a straight-chain or branched-chain alkyl group in which the carbon atom bonded to the oxygen atom is a secondary carbon atom.

[0026] Y 1 ~Y 4 Examples of the ester group of Y -COO-R 1 ···(i) In the general formula (i), R 1 is an alkyl group or an aryl group. R 1 The number of carbon atoms in the alkyl group is preferably small in terms of the conductivity of the material. Therefore, R 1The number of carbon atoms in the alkyl group is preferably 30 or less, more preferably 20 or less, still more preferably 15 or less, and particularly preferably 10 or less. Also, R 1 The number of carbon atoms in the alkyl group is preferably 1 or more, more preferably 4 or more, still more preferably 6 or more, and particularly preferably 8 or more. R 1 The alkyl group of R 1 may be linear or cyclic. When the alkyl group is linear, it may be straight-chain or branched-chain. From the viewpoint of ease of synthesis, it is preferably a straight-chain or branched-chain alkyl group in which the carbon atom bonded to the oxygen atom is a primary carbon atom. From the viewpoint of material solubility, it is preferably a branched-chain alkyl group in which the carbon atom bonded to the oxygen atom is a primary carbon atom, or a straight-chain, branched-chain or cyclic alkyl group in which the carbon atom bonded to the oxygen atom is a secondary carbon atom. More preferably, it is a straight-chain, branched-chain or cyclic alkyl group in which the carbon atom bonded to the oxygen atom is a secondary carbon atom. Still more preferably, it is a straight-chain or branched-chain alkyl group in which the carbon atom bonded to the oxygen atom is a secondary carbon atom.

[0027] R 1 The number of carbon atoms in the aryl group of R 1 is preferably small from the viewpoint of the conductivity of the material. Therefore, the number of carbon atoms in the aryl group of R 1 is preferably 18 or less, more preferably 12 or less, still more preferably 10 or less, and particularly preferably 6. Note that the lower limit of the number of carbon atoms in the aryl group of R 1 is 6. R 1 The aryl group of R 1 may or may not have a substituent. That is, the aryl group of R 1 is an unsubstituted or substituted aryl group. Examples of the substituent include an alkyl group, an alkoxy group, a hydroxy group, an amino group, and the like.

[0028] Y 1 ~Y 4 ​​​​​​may be the same or different. In particular, from the viewpoint of being likely to form a lamellar structure in the film obtained using the compound of the present invention, Y 1 and Y 3 one of them is a hydrogen atom and the other is an alkyl group, an alkoxy group or an ester group, and it is preferable that Y 2 and Y 4 one of them is a hydrogen atom and the other is an alkyl group, an alkoxy group or an ester group. In terms of shifting the absorption wavelength to a longer wavelength, Y 1 and Y 2 are each independently an alkyl group, an alkoxy group or an ester group, and it is preferable that Y 3 and Y 4 are hydrogen atoms. Among them, particularly from the viewpoint of ease of synthesis, it is more preferable that Y 1 and Y 2 are the same, and it is even more preferable that Y 1 and Y 2 are alkoxy groups and Y 3 and Y 4 are hydrogen atoms. Further, as another aspect, from the viewpoint that the orientations of the substituents are parallel and it is easier to form a lamellar structure, Y 1 and Y 4 are each independently an alkyl group, an alkoxy group or an ester group, and it is preferable that Y 2 and Y 3 are hydrogen atoms. It is more preferable that Y 1 and Y 4 are each independently an alkyl group or an alkoxy group, and it is even more preferable that Y 2 and Y 3 are hydrogen atoms. It is still more preferable that one of Y 1 and Y 4 is an alkyl group and the other is an alkoxy group, and it is most preferable that Y 2 and Y 3 are hydrogen atoms, and it is most preferable that Y 1 is an alkoxy group and Y 4 is an alkyl group, and Y 2 and Y 3 are hydrogen atoms.

[0029] In the general formula (1), Z1 and Z 2 is each independently an oxygen atom or a dicyanomethylene group. In compound (1), Z 1 and Z 2 are considered to be able to become an electron-withdrawing group in the acceptor part by being an oxygen atom or a dicyanomethylene group. Z 1 and Z 2 are both preferably a dicyanomethylene group in terms of enhancing the electron-withdrawing property.

[0030] In general formula (1), M is a carbon atom substituted with an alkyl group or an aryl group, a silicon atom substituted with an alkyl group or an aryl group, or a germanium atom substituted with an alkyl group or an aryl group. Compound (1) is considered to be able to enhance solubility by M being a carbon atom substituted with an alkyl group or an aryl group, a silicon atom substituted with an alkyl group or an aryl group, or a germanium atom substituted with an alkyl group or an aryl group. The carbon atom substituted with an alkyl group or an aryl group is represented by the following general formula (ii). The silicon atom substituted with an alkyl group or an aryl group is represented by the following general formula (iii). The germanium atom substituted with an alkyl group or an aryl group is represented by the following general formula (iv).

[0031]

Chemical formula

[0032] In general formulas (ii) to (iv), R 2 ~R 7 are each independently an alkyl group or an aryl group. R 2 ~R 7 As the alkyl group of, examples include the alkyl groups of R 1 ~Y 4 exemplified above in the description of. 1 R 2 ~R 7 As the aryl group of, examples include the aryl groups of Y 1~Y 4 In the description of 4 , the R exemplified above 1 aryl group may be mentioned. In terms of the ease of synthesis of compound (1), the two alkyl groups or aryl groups possessed by a carbon atom, a silicon atom, and a germanium atom are preferably the same. From the viewpoint of synthesis cost, M is preferably a carbon atom substituted with an alkyl group or an aryl group or a silicon atom substituted with an alkyl group or an aryl group. Among them, in particular, from the viewpoint of the elongation of the absorption wavelength, a carbon atom substituted with an alkyl group or an aryl group is more preferable, and a carbon atom substituted with an alkyl group is even more preferable.

[0033] As compound (1), X in general formula (1) 1 ~X 4 are the same and are a chlorine atom, a fluorine atom, or a cyano group, Y 1 and Y 2 are each independently an alkyl group, an alkoxy group, or an ester group, Y 3 and Y 4 are hydrogen atoms, Z 1 and Z 2 are dicyanomethylene groups, and a compound in which M is a carbon atom substituted with an alkyl group or an aryl group is preferable. Among them, in particular, a compound in which Y 1 and Y 2 are the same and are an alkoxy group is more preferable. Also, as another aspect, as compound (1), X in general formula (1) 1 ~X 4 are the same and are a chlorine atom, a fluorine atom, or a cyano group, Y 1 and Y 4 are each independently an alkyl group, an alkoxy group, or an ester group, Y 2 and Y 3 are hydrogen atoms, Z 1 and Z 2 are dicyanomethylene groups, and a compound in which M is a carbon atom substituted with an alkyl group or an aryl group is preferable. Among them, in particular, a compound in which Y 1 and Y 4A compound in which one is an alkyl group and the other is an alkoxy group is more preferable.

[0034] Specific examples of compound (1) include compounds represented by the following formulas (1-1) to (1-72), etc., but compound (1) is not limited thereto. In this specification, for example, the compound represented by the following formula (1-1) is referred to as "compound (1-1)". The same applies to the compounds represented by the following formulas (1-2) to (1-72).

[0035]

Chemical formula

[0036]

Chemical formula

[0037]

Chemical formula

[0038]

Chemical formula

[0039]

Chemical formula

[0040]

Chemical formula

[0041]

Chemical formula

[0042]

Chemical formula

[0043] [Chemical formula]

[0044] Among the above-mentioned compounds, for Y 1 ~Y 4 at least one of which is an alkoxy group, and in the alkoxy group, the alkyl group bonded to the oxygen atom is linear, branched or cyclic, and the carbon atom bonded to the oxygen atom is a secondary carbon atom (that is, the alkoxy group bonded to the thiophene ring is branched at the 1-position) is particularly excellent in solubility. Examples of such compounds include compounds (1-28) to (1-39), (1-52) to (1-72), etc.

[0045] The production method of compound (1) is not particularly limited, but as an example of the production method of compound (1), the production method of the compound (A) of the following formula will be specifically described. X in compound (A) is X of compound (1) 1 ~X 4 corresponding to any of them, Y in compound (A) is Y of compound (1) 1 ~Y 4 corresponding to any of them, Z in compound (A) is Z of compound (1) 1 and Z 2 corresponding to them, and M in compound (A) corresponds to M of compound (1).

[0046] [Chemical formula]

[0047] First, a compound (B) of the following formula, which is a 3-substituted thiophene, is reacted with lithium diisopropylamide (LDA) in a reaction solvent, and then N,N-dimethylformamide is further reacted to obtain a compound (C) of the following formula.

[0048] [Chemical formula]

[0049] Here, compound (B) may be synthesized by a known method or a commercially available product may be used. Regarding the charging ratio of raw materials, for compound (B), it is preferable that LDA is 0.9 to 1.5 equivalents, and it is preferable that N,N-dimethylformamide is 0.9 equivalent or more. Note that N-formylpiperidine may be used instead of N,N-dimethylformamide. The reaction solvent is not particularly limited as long as it does not react with the raw material compounds. Examples include saturated aliphatic hydrocarbon solvents such as hexane; ether solvents such as tetrahydrofuran (THF), diethyl ether, cyclopentyl methyl ether, and methyl t-butyl ether; aromatic hydrocarbon solvents such as toluene and xylene, etc. The reaction temperature is preferably -78 to 50°C. The reaction time is preferably 10 minutes to 12 hours after adding LDA and 10 minutes to 12 hours after adding N,N-dimethylformamide.

[0050] Next, compound (C) and N-bromosuccinimide (NBS) are reacted in a reaction solvent to obtain compound (D) of the following formula.

[0051]

Chemical formula

[0052] Regarding the charging ratio of raw materials, for compound (C), it is preferable that NBS is 0.9 to 1.2 equivalents, and more preferably 0.9 to 1.05 equivalents. Note that bromine may be used instead of NBS. The reaction solvent is not particularly limited as long as it does not react with the raw material compounds. Examples include saturated aliphatic hydrocarbon solvents such as hexane; ether solvents such as tetrahydrofuran (THF); aromatic hydrocarbon solvents such as toluene and xylene; halogen solvents such as chloroform; N,N-dimethylformamide, etc. The reaction temperature is preferably -78 to 50°C. The reaction time is preferably 10 minutes to 24 hours after adding NBS.

[0053] In the production of compound (A), instead of compound (D), a compound (F) of the following formula may be used. Compound (F) can be obtained, for example, as follows.

[0054] That is, first, a compound (B) of the following formula, which is a 3-substituted thiophene, is reacted with lithium diisopropylamide (LDA) in a reaction solvent, and then 1,2-dibromo-1,1,2,2-tetrachloroethane is further reacted to obtain a compound (E) of the following formula.

[0055]

Chemical formula

[0056] Here, compound (B) may be synthesized by a known method or a commercially available product may be used. Regarding the charging ratio of raw materials, it is preferable that LDA is 0.9 to 1.5 equivalents and 1,2-dibromo-1,1,2,2-tetrachloroethane is 0.9 equivalent or more with respect to compound (B). The reaction solvent is not particularly limited as long as it does not react with the raw material compounds, and examples include saturated aliphatic hydrocarbon solvents such as hexane; ether solvents such as tetrahydrofuran (THF), diethyl ether, cyclopentyl methyl ether, and methyl t-butyl ether; aromatic hydrocarbon solvents such as toluene and xylene, etc. The reaction temperature is preferably -78 to 50°C. The reaction time is preferably 10 minutes to 12 hours after adding LDA and 10 minutes to 12 hours after adding 1,2-dibromo-1,1,2,2-tetrachloroethane.

[0057] Next, compound (E) and lithium diisopropylamide (LDA) are reacted in a reaction solvent, and then N,N-dimethylformamide is further reacted to obtain a compound (F) of the following formula.

[0058]

Chemical formula

[0059] The charging ratio of raw materials is preferably such that LDA is 0.9 to 1.5 equivalents and N,N-dimethylformamide is 0.9 equivalent or more with respect to compound (E). Note that N-formylpiperidine may be used instead of N,N-dimethylformamide. The reaction solvent is not particularly limited as long as it does not react with the raw material compounds, and examples thereof include saturated aliphatic hydrocarbon solvents such as hexane; ether solvents such as tetrahydrofuran (THF), diethyl ether, cyclopentyl methyl ether, and methyl t-butyl ether; and aromatic hydrocarbon solvents such as toluene and xylene. The reaction temperature is preferably -78 to 50°C. The reaction time is preferably 10 minutes to 12 hours after adding LDA and 10 minutes to 12 hours after adding N,N-dimethylformamide.

[0060] Next, in the reaction solvent, compound (I) is obtained by a cross-coupling reaction of at least one of compound (D) and compound (F) with compound (G) of the following formula. The production method of compound (I) is not particularly limited. For example, compound (I) can be produced by a method similar to the methods described in literatures such as Adv. Energy Mater., 2018, Vol. 8, p. 1801212.; J. Mater. Chem. C, 2020, Vol. 8, p. 15175.; ACS Energy Lett., 2019, Vol. 4, p. 1401. An example of specific production conditions is as follows.

[0061]

Chemical formula

[0062] Here, compound (G) may be synthesized by known methods (e.g., Polym. Chem., 2013, Vol. 4, p. 5351 - 5360; J. Phys. Chem. C, 2011, Vol. 15, p. 2398 - 2405; Chem. Commun., 2012, Vol. 48, p. 11130 - 11132), or commercially available products may be used. Also, compound (G) corresponding to the cross - coupling reaction (where "L" in compound (G) is an alkyltin group, boric acid, boric acid ester group, zinc halide, magnesium halide, or silyl group, etc.) may be used. The type of cross - coupling reaction, which is a reaction between at least one of compound (D) and compound (F) and compound (G), is not particularly limited, and the reaction can be carried out by Stille coupling, Suzuki coupling, Negishi coupling, Kumada coupling, Hiyama coupling, etc. The cross - coupling reaction may be carried out in the presence of a catalyst such as a palladium catalyst, nickel catalyst, or copper catalyst. For example, when reacting compound (D) or compound (F) with compound (G) by the Stille coupling reaction, the charging ratio of the raw materials is preferably such that compound (D) or compound (F) is 1.9 - 3.0 equivalents relative to compound (G). Also, it is preferable to use a palladium catalyst during the Stille coupling reaction, and the palladium content in the catalyst is preferably 0.1 - 50 mol%. The reaction solvent is not particularly limited as long as it does not react with the raw material compounds, and examples include saturated aliphatic hydrocarbon solvents such as hexane; ether solvents such as diethyl ether, cyclopentyl methyl ether, tetrahydrofuran (THF), 1,4 - dioxane; aromatic hydrocarbon solvents such as toluene, xylene; N,N - dimethylformamide (DMF), dimethyl sulfoxide, N - methyl - 2 - pyrrolidone, etc. The reaction temperature is preferably 20°C to the reflux temperature of the reaction solvent. The reaction time is preferably 1 - 24 hours.

[0063] Separately, the compound (J) of the following formula and malononitrile are reacted in the presence of sodium acetate and a reaction solvent to obtain the compound (K) of the following formula.

[0064] [Chemical formula]

[0065] Here, the compound (J) can be synthesized by a known method (for example, Chinese Patent Application Publication No. 109928894, JP-A-2018-8999). The charging ratio of the raw materials is preferably 1.2 to 3.0 equivalents, more preferably 1.5 to 3.0 equivalents, still more preferably 1.8 to 2.2 equivalents, and particularly preferably 1.8 to 2.0 equivalents of malononitrile with respect to the compound (J). Also, with respect to the compound (J), it is preferable that sodium acetate is 1.0 to 3.0 equivalents. The reaction solvent is not particularly limited as long as it does not react with the raw material compounds, and examples thereof include alcohol solvents such as absolute ethanol. The reaction temperature is preferably 0 to 100°C. The reaction time is preferably from 10 minutes to 12 hours.

[0066] Next, in the reaction solvent, in the presence of an acid catalyst or a base catalyst, the compound (I) is reacted with the compound (J) or the compound (K) to obtain the compound (A). The production method of the compound (A) is not particularly limited. For example, under acid catalyst conditions, the compound (A) can be produced by a method similar to the methods described in JP-A-2022-511781; JP-A-2023-500815, etc. On the other hand, under base catalyst conditions, the compound (A) can be produced by a method similar to the methods described in Adv. Energy Mater., 2018, Vol. 8, p. 1801212.; J. Mater. Chem. C, 2020, Vol. 8, p. 15175.; ACS Energy Lett., 2019, Vol. 4, p. 1401., etc. An example of specific production conditions is as follows.

[0067] [Chemical formula]

[0068] Examples of the acid catalyst include p-toluenesulfonic acid hydrate (PTSA·H2O). Examples of the base catalyst include pyridine and piperidine. The charging ratio of the raw materials is preferably such that compound (J) or compound (K) is 1.9 to 10 equivalents relative to compound (I). The acid catalyst is preferably 2.1 to 11 equivalents. The base catalyst is preferably 1 to 10% by mass based on the reaction solvent. The reaction solvent is not particularly limited as long as it does not react with the raw material compounds. Examples include alcohol solvents such as methanol and ethanol; aromatic hydrocarbon solvents such as toluene and xylene; halogen solvents such as chloroform, etc., and these may be used in combination. The reaction temperature is preferably from room temperature to reflux temperature. The reaction time is preferably from 10 minutes to 24 hours.

[0069] In this way, compound (A) can be produced. Here, X in compound (A) is X of compound (1) 1 ~X 4 and Y in compound (A) is Y of compound (1) 1 ~Y 4 and Z in compound (A) is Z of compound (1) 1 or Z 2 and M in compound (A) is M of compound (1).

[0070] Since the compound of the present invention can maintain the light absorption property while shifting the absorption wavelength to a longer wavelength, it is suitable as an n-type semiconductor material (light absorption material and electron transport material) used in a photoelectric conversion element. The use of the compound of the present invention is not limited to the above. For example, since the compound of the present invention also has excellent luminescence properties, it can also be used in bioimaging, organic EL, near-infrared luminescent dyes for wavelength conversion films / compositions, etc.

[0071] [Composition] The composition of the present invention contains the above-described compound (1). Compound (1) may be used alone, or two or more kinds thereof may be used in any ratio in combination. The content of compound (1) in the composition of the present invention is not particularly limited. However, when the composition of the present invention is used for forming the photoelectric conversion layer (active layer) of a photoelectric conversion element, the content of compound (1) is preferably large in terms of light absorption amount, and on the other hand, preferably small in terms of carrier balance. Therefore, with respect to the total amount (total mass) of all components other than the solvent in the composition of the present invention, the content of compound (1) is preferably 10% by mass or more, more preferably 25% by mass or more, and even more preferably 40% by mass or more. Also, with respect to the total amount (total mass) of all components other than the solvent in the composition of the present invention, the content of compound (1) is preferably 100% by mass or less, more preferably 90% by mass or less, even more preferably 75% by mass or less, and particularly preferably 60% by mass or less.

[0072] The composition of the present invention may further contain a solvent. The composition containing compound (1) and a solvent is suitable as an ink (composition for forming an active layer) for forming the photoelectric conversion layer (active layer) of a photoelectric conversion element. As the solvent, a liquid that does not react with compound (1) and dissolves compound (1) is preferred, and examples thereof include aromatic hydrocarbon solvents such as toluene and xylene; halogen-based solvents such as dichloromethane and chloroform. When the composition of the present invention contains a solvent, the solvent may be used alone, or two or more kinds thereof may be used in any ratio in combination. When the composition of the present invention contains a solvent, the content of compound (1) in the composition of the present invention is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and even more preferably 1.0% by mass or more, based on the total mass of the composition of the present invention. Also, the content of compound (1) is preferably 5.0% by mass or less, more preferably 3.5% by mass or less, and even more preferably 2.0% by mass or less, based on the total mass of the composition of the present invention.

[0073] When the composition of the present invention is used as a composition for forming an active layer, the composition preferably further contains a p-type semiconductor material in addition to compound (1). The p-type semiconductor material is not particularly limited as long as it can be used in the photoelectric conversion layer of an organic optoelectronic conversion element. Examples include polymers described in the literature (ACS Energy Lett., 2019, Vol. 4, p. 1401; Adv. Optical Mater., 2022, Vol. 10, p. 2200747). When the composition of the present invention contains a p-type semiconductor material, the p-type semiconductor material may be used alone or in combination of two or more in any ratio. The mass ratio of compound (1) to the p-type semiconductor material (compound (1) / p-type semiconductor material) is preferably 0.1 or more, more preferably 0.5 or more, and even more preferably 0.75 or more. Also, the mass ratio of compound (1) to the p-type semiconductor material is preferably 3.0 or less, more preferably 2.0 or less, and even more preferably 1.5 or less.

[0074] The composition of the present invention may further contain components other than compound (1), the p-type semiconductor material, and the solvent (optional components) as necessary, as long as the effects of the present invention are not impaired. Examples of the optional components include 1,8-diiodooctane and 1-chloronaphthalene. When the composition of the present invention contains optional components, the optional components may be used alone or in combination of two or more in any ratio. When containing an optional component, it is preferable that the amount of the optional component is large in terms of the easy manifestation of the effect by containing the optional component. On the other hand, in terms of the easy maintenance of the physical properties suitable for the photoelectric conversion element of the composition of the present invention, it is preferable that the content of the compound (1) is large. Therefore, when the composition of the present invention contains an optional component, the content of the optional component is preferably 0.1% by mass or more, more preferably 0.3% by mass or more, based on the total amount (total mass) of all components other than the solvent in the composition of the present invention. Further, the content of the optional component is preferably 2.0% by mass or less, more preferably 1.0% by mass or less, based on the total amount (total mass) of all components other than the solvent in the composition of the present invention.

[0075] The composition of the present invention can be obtained, for example, by dissolving the compound (1) and, if necessary, one or more of the p-type semiconductor material and the optional component in a solvent. Further, by removing the solvent from the obtained composition, a composition of the present invention not containing the solvent can be obtained.

[0076] The composition of the present invention is suitable as an ink (composition for forming an active layer) for forming a photoelectric conversion layer (active layer) of a photoelectric conversion element.

[0077] [Film] The film of the present invention is a film containing the above-described compound (1) and is also referred to as an organic thin film. The film of the present invention can be obtained, for example, by removing the solvent from the above-described composition of the present invention containing the solvent. Specifically, it can be obtained by applying the composition of the present invention on a substrate and then drying it. The content of compound (1) in the film is the same as the content of compound (1) with respect to the total amount (total mass) of all components other than the solvent in the composition of the present invention described above. That is, with respect to the total mass of the film, the content of compound (1) is preferably 10% by mass or more, more preferably 25% by mass or more, and even more preferably 40% by mass or more. Also, with respect to the total mass of the film, the content of compound (1) is preferably 100% by mass or less, more preferably 90% by mass or less, even more preferably 75% by mass or less, and particularly preferably 60% by mass or less.

[0078] The film thickness is preferably thick in terms of the light absorption amount. On the other hand, in terms of the external quantum efficiency (EQE) when the film of the present invention is used as the photoelectric conversion layer (active layer) of a photoelectric conversion device, the film thickness is preferably thin. Therefore, the film thickness is preferably 10 nm or more, and more preferably 100 nm or more. Also, the film thickness is preferably 1000 nm or less, and more preferably 500 nm or less. The film thickness can be adjusted by the coating amount of the composition applied to the substrate.

[0079] The coating method of the composition is not particularly limited, and examples include brush coating, bar coating, spray coating, dip coating, spin coating, curtain coating, etc. The drying temperature after coating is preferably 20 to 250 °C. The drying time is preferably 10 minutes to 5 hours.

[0080] The film of the present invention is suitable as the photoelectric conversion layer (active layer) of a photoelectric conversion device.

[0081] [Photoelectric conversion device] The photoelectric conversion device of the present invention is a device comprising the film of the present invention described above, and is also referred to as an organic photoelectric conversion device. Specifically, the photoelectric conversion device of the present invention comprises the film of the present invention as the photoelectric conversion layer (active layer). The structure of the photoelectric conversion element can adopt the structure of a known organic photoelectric conversion element. For example, reference can be made to the description in Japanese Patent Application Laid-Open No. 2007-324587. Although the specific structure is not particularly limited, examples include an element having a laminated structure in which a photoelectric conversion layer (active layer) is sandwiched between a pair of electrodes.

[0082] Hereinafter, an example of the photoelectric conversion element of the present invention will be described with reference to FIG. 1. In addition, in each of the drawings used in the following description, for the sake of easy understanding of the features, the characteristic portions may be shown enlarged for convenience, and the dimensional ratios of the respective components may be different from the actual ones. Further, the materials, dimensions, etc. exemplified in the following description are merely examples, and the present invention is not limited thereto, and can be appropriately changed and implemented without changing the gist thereof.

[0083] The photoelectric conversion element 10 shown in FIG. 1 has a structure in which a transparent electrode 12, a hole transport layer 13, a photoelectric conversion layer 14, an electron transport layer 15, and a metal electrode 16 are laminated in this order on a transparent substrate 11. Note that the positions of the hole transport layer 13 and the electron transport layer 15 may be exchanged. That is, the photoelectric conversion element may have a structure in which a transparent electrode, an electron transport layer, a photoelectric conversion layer (active layer), a hole transport layer, and a metal electrode are laminated in this order on a transparent substrate.

[0084] Examples of the transparent substrate 11 include a base material having an average transmittance of 80% or more in visible light of 450 nm or more. Examples of the material for forming the transparent substrate 11 include glass; plastics such as polyethylene terephthalate, polyethylene naphthalate, polycarbonate, and polyethylene sulfide.

[0085] Examples of the transparent electrode 12 include an electrode having an average transmittance of 80% or more in visible light of 450 nm or more. The material for forming the transparent electrode 12 is not particularly limited as long as the transparent electrode 12 can be formed. For example, indium tin oxide (ITO) doped with tin, indium zinc oxide (IZO) doped with zinc, indium tungsten oxide (IWO) doped with tungsten, zinc aluminum oxide (AZO), indium oxide (In2O3), zinc oxide (ZnO), titanium dioxide (TiO2), etc. can be mentioned.

[0086] The metal electrode 16 is an electrode paired with the transparent electrode 12. The material constituting the metal electrode 16 is not particularly limited. For example, metals such as gold, platinum, silver, aluminum, nickel, titanium, magnesium, calcium, barium, sodium, chromium, copper, and cobalt, or their alloys, etc. can be mentioned. The metal electrode 16 is preferably a transparent electrode or a reflective electrode. That is, the photoelectric conversion element preferably has a laminated structure in which a photoelectric conversion layer (active layer) is sandwiched between a pair of electrodes (transparent or metal), and more preferably has a laminated structure in which an electron transport layer, a photoelectric conversion layer (active layer), and a hole transport layer are sandwiched between a pair of electrodes (transparent or metal). The materials for forming the electrodes in the case of a pair of transparent electrodes may be of the same type or different types. The film thickness of the metal electrode 16 is not particularly limited. From the viewpoint of enhancing transparency, about 10 nm is preferable. When transparency is not required, considering durability, etc., 40 nm or more is preferable, and 100 nm or more is more preferable.

[0087] The method for forming the transparent electrode 12 and the metal electrode 16 is not particularly limited. For example, it can be formed by dry processes such as vacuum evaporation and sputtering; wet processes using conductive ink, etc.

[0088] When providing the constituent members and manufacturing method in the case of providing the hole transport layer 13 and the electron transport layer 15, there are no particular restrictions, and known techniques can be used. For example, the members and their manufacturing methods described in known documents such as International Publication No. 2013 / 171517, International Publication No. 2013 / 180230, or Japanese Patent Application Laid-Open No. 2012-191194 can be used.

[0089] The photoelectric conversion layer 14 is a layer that absorbs light and separates charges. The photoelectric conversion layer 14 of the photoelectric conversion element of the present invention is a layer containing the compound (1) of the present invention described above. More specifically, it is the film of the present invention described above. The photoelectric conversion layer 14 can be formed, for example, by applying the composition of the present invention described above onto a layer below the photoelectric conversion layer 14 such as the hole transport layer 13 and drying it.

[0090] The photoelectric conversion element 10 can be obtained, for example, by forming a transparent electrode 12, a hole transport layer 13, a photoelectric conversion layer 14, an electron transport layer 15, and a metal electrode 16 in this order on a transparent substrate 11.

[0091] Since the photoelectric conversion layer 14 of the photoelectric conversion element of the present invention contains the compound (1), it can suppress the dark current while making the absorption wavelength longer and has high sensor sensitivity on the long-wavelength side.

[0092] [CMOS Image Sensor] The CMOS image sensor of the present invention includes the photoelectric conversion element of the present invention described above. The structure of the CMOS image sensor can adopt the structure of a known CMOS image sensor. Specifically, for example, reference can be made to the description in Japanese Patent Application Laid-Open No. 2021-57422, etc., and it is not particularly limited. More specifically, a CMOS image sensor having a structure in which a metal wiring, the photoelectric conversion element of the present invention, a color filter, and a microlens are laminated in this order on a substrate such as a silicon substrate can be mentioned.

Examples

[0093] Hereinafter, the present invention will be described in more detail with reference to examples. However, the following examples do not limit the scope of the present invention.

[0094] [Compound] As model compounds of compound (1), model compounds (1-11-1), (1-5-1), (1-8-1), (1-2-1) of the following formula were used, and as model comparative compounds of compound (1), model comparative compounds (N-1), (N-2) of the following formula were used. Note that the model comparative compound (N-1) was set with reference to a known document ("ACS Energy Lett.", 2019, Vol. 4, p. 1401.). The model comparative compound (N-2) was set with reference to a known document ("Sci. Adv.", 2023, Vol. 9, eadf6152.).

[0095] [Chemical formula]

[0096] [Measurement and evaluation method] [Evaluation based on theoretical calculation] The bathochromic shift and absorbance of each model compound and model comparative compound were evaluated based on the following theoretical calculations. As software for molecular orbital calculations, Spartan’20 manufactured by Wavefunction was used, and the HOMO-LUMO gap and oscillator strength of each compound were obtained by theoretical calculations. B3LYP / 6-31G(d) was adopted as the calculation method for the HOMO-LUMO gap, and TD-B3LYP / 6-31G(d) / / B3LYP / 6-31G(d) was adopted as the calculation method for the oscillator strength. The HOMO-LUMO gap of each compound was evaluated as an index for the bathochromic shift of the absorption wavelength, and the oscillator strength of each compound was evaluated as an index for absorbance. Note that the HOMO-LUMO gap and oscillator strength of the model comparative compound (N-1) were used as reference values. The absorbance was evaluated based on the following evaluation criteria. These results are shown in Table 1. [Evaluation criteria for absorbance] 〇: Decrease or improvement of less than 5% from the reference value △: 5% to 25% decrease from the reference value ×: Decrease exceeding 25% from the reference value

[0097]

Table 1

[0098] As is clear from the results in Table 1, for the model comparison compound (N-1) (reference value), the model comparison compound (N-2) substituted with a strong electron-withdrawing group was able to reduce the HOMO-LUMO gap, but showed a significant decrease in oscillator strength, making it difficult to achieve both a longer absorption wavelength and absorbance. On the other hand, the model compounds (1-11-1), (1-5-1), (1-8-1), and (1-2-1) into which a pyrazine ring was introduced, which are model compounds of the compound (1) of the present invention, were able to reduce the HOMO-LUMO gap while maintaining the reference value in terms of oscillator strength. Therefore, it was shown that the compound (1) of the present invention can have a longer absorption wavelength while maintaining absorbance, as compared with conventional A-D-A type non-fullerene acceptor materials.

Industrial Applicability

[0099] The compound of the present invention can have a longer absorption wavelength while maintaining absorbance, and is useful as a semiconductor material used in a photoelectric conversion element.

Explanation of Symbols

[0100] 10 Photoelectric conversion element 11 Transparent substrate 12 Transparent electrode 13 Hole transport layer 14 Photoelectric conversion layer 15 Electron transport layer 16 Metal electrode

Claims

1. A compound represented by the following general formula (1). 【Chemical 1】 In general formula (1), X １ to X ４ are each independently a hydrogen atom, a chlorine atom, a fluorine atom, a bromine atom or a cyano group, Y １ to Y ４ are each independently a hydrogen atom, an alkyl group, an alkoxy group or an ester group, Z １ and Z ２ are each independently an oxygen atom or a dicyanomethylene group, and M is a carbon atom substituted with an alkyl group or an aryl group, a silicon atom substituted with an alkyl group or an aryl group, or a germanium atom substituted with an alkyl group or an aryl group.

2. Z in the general formula (1) above １ and Z ２ The compound according to claim 1, wherein is a dicyanomethylene group.

3. X in the general formula (1) above １ ~X ４ are the same and are a hydrogen atom, a chlorine atom, a fluorine atom or a cyano group, the compound according to claim 1.

4. The compound according to claim 1, wherein M in the general formula (1) is a carbon atom substituted with an alkyl group or an aryl group or a silicon atom substituted with an alkyl group or an aryl group.

5. Y in the general formula (1) above １ and Y ３ One of them is a hydrogen atom, and the other is an alkyl group, an alkoxy group or an ester group. Y ２ and Y ４ The compound according to claim 1, wherein one of them is a hydrogen atom and the other is an alkyl group, an alkoxy group or an ester group.

6. Y in the general formula (1) above １ and Y ２ are each independently an alkyl group, an alkoxy group or an ester group, and Y ３ and Y ４ is a hydrogen atom, the compound according to claim 1.

7. Y in the general formula (1) above １ and Y ４ are each independently an alkyl group, an alkoxy group or an ester group, and Y ２ and Y ３ is a hydrogen atom. The compound according to claim 1

8. X in the general formula (1) above １ ~X ４ are the same and are a chlorine atom, a fluorine atom or a cyano group, Y １ and Y ２ are the same and are an alkoxy group, Y ３ and Y ４ are hydrogen atoms, Z １ and Z ２ are dicyanomethylene groups, and M is a carbon atom substituted with an alkyl group or an aryl group. The compound according to claim 1.

9. A composition containing the compound according to any one of claims 1 to 8.

10. A film containing the compound according to any one of claims 1 to 8.

11. A photoelectric conversion element provided with the film according to claim 10.

12. A CMOS image sensor provided with the photoelectric conversion element according to claim 11.

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