Photoelectric conversion elements and electron transport materials

Abstract

The present invention provides a photoelectric conversion element and an electron transport material that can improve electron transport capability or reduce energy barriers with adjacent layers. [Solution] The device includes a light-receiving layer and an organic layer positioned between a first electrode and a second electrode, the organic layer containing a compound represented by the following formula (1). JPEG2026127045000059.jpg33141 (In formula (1), R 2 and R 3 Each of the following independently represents an aliphatic hydrocarbon group having 1 to 15 carbon atoms, and the aliphatic hydrocarbon group may be substituted with one or more groups selected from a hydroxyl group, a carboxyl group, a formyl group, a nitro group, a fluoro group, a chloro group, a bromo group, an iodo group, a trifluoromethyl group, a cyano group, a carbon-oxygen double bond, a carbon-sulfur double bond, an aromatic hydrocarbon group having 6 to 20 carbon atoms, a heteroaromatic group having 3 to 20 carbon atoms, and an aliphatic hydrocarbon group having 1 to 15 carbon atoms. The aliphatic hydrocarbon group may be linear, branched, or cyclic, and m and n each independently represent 1, 2, or 3.

Description

[Technical Field]

[0001] The present invention relates to a photoelectric conversion element and an electron transport material comprising an imide compound having an imide skeleton as a partial structure. [Background technology]

[0002] Currently, there are active efforts to create new high-performance devices using organic materials. In particular, research and development on organic electronic elements such as photoelectric converters and organic EL elements is thriving, and material and device design aimed at improving the performance of these devices is progressing. For example, in photoelectric converters used for video recording, there was a problem that if the rate at which carriers (electrons and holes) generated in the light-receiving layer were transported to the electrodes was slow, it would cause afterimages. In organic EL elements, there was a problem that if the rate at which carriers were transported from the electrodes to the light-emitting layer was slow, the driving voltage would increase. Therefore, in order to improve the performance of devices, highly efficient carrier movement within the element is required.

[0003] Incidentally, imide compounds have been disclosed as compounds for electron transport materials used in electrophotographic photoreceptors (see Patent Document 1). However, further performance improvements are required in the field of organic electronic devices, and therefore, further refinements are necessary. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2019-182789 [Overview of the project] [Problems that the invention aims to solve]

[0005] The object of the present invention is to provide a photoelectric conversion element and an electron transport material that can improve electron transport capability or reduce energy barriers with adjacent layers. [Means for solving the problem]

[0006] As a result of diligent research to solve the above problems, the inventors of the present invention have found that certain compounds having an imide skeleton as a partial structure can improve the electron transport capability in photoelectric conversion elements, and have completed the present invention.

[0007] In other words, the present invention encompasses the following aspects. [1] comprising a first electrode, a second electrode, and a light-receiving layer and an organic layer disposed between the first electrode and the second electrode, The aforementioned organic layer includes an electron transport layer, The electron transport layer is a photoelectric conversion element containing a compound represented by the following formula (1). [ka] (In formula (1), R 2 and R 3 Each of these independently represents an aliphatic hydrocarbon group having 1 to 15 carbon atoms. The aliphatic hydrocarbon group may be substituted with one or more groups selected from hydroxyl groups, carboxyl groups, formyl groups, nitro groups, fluoro groups, chloro groups, bromo groups, iodo groups, trifluoromethyl groups, cyano groups, carbon-oxygen double bonds, carbon-sulfur double bonds, aromatic hydrocarbon groups having 6 to 20 carbon atoms, heteroaromatic groups having 3 to 20 carbon atoms, and aliphatic hydrocarbon groups having 1 to 15 carbon atoms. The aliphatic hydrocarbon group may be linear, branched, or cyclic, and m and n each independently represent 1, 2, or 3. Ring A represents an aromatic hydrocarbon ring with 6 to 20 carbon atoms, or a heteroaromatic ring with 4 to 20 carbon atoms. The aromatic hydrocarbon ring and the heteroaromatic ring may each be a monoring, a fused ring, or a linked ring, and the linked ring may be bonded by methylene groups substituted with trifluoromethyl groups. The aromatic hydrocarbon ring and the heteroaromatic ring may be substituted with one or more groups selected from a hydroxyl group, a carboxyl group, a formyl group, a nitro group, a cyano group, a fluoro group, a chloro group, a bromo group, an iodo group, a fluoroalkyl group having 1 to 10 carbon atoms, a fluoroalkoxy group having 1 to 10 carbon atoms, an alkyl group having 1 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 20 carbon atoms, and a heteroaromatic group having 3 to 20 carbon atoms. The aromatic hydrocarbon ring and the heteroaromatic ring may be bonded to the aromatic hydrocarbon group or the heteroaromatic group by one or more selected from an oxygen atom, a carbonyl group, and a thiocarbonyl group. The aromatic hydrocarbon group and the heteroaromatic group may each be a monocyclic, fused, or linked ring. [2] The photoelectric conversion element according to [1], wherein the photoelectric conversion element is for use as an image sensor. [3] The photoelectric conversion element according to [1] or [2], wherein the light-receiving layer is a layer containing at least two organic components. [4] The photoelectric conversion element according to any one of [1] to [3], wherein the ring A in formula (1) may be replaced with one or more of the following (A-1) to (A-17). [ka] [5] The photoelectric element according to [4], wherein ring A in formula (1) may be substituted with one or more of the groups described above (A-1) or (A-2). [6] R in equation (1) above 2 and R 3 However, each is independently a methylene group or an ethylene group, The methylene group and the ethylene group may be substituted with one or more groups selected from a hydroxyl group, a carboxyl group, a formyl group, a nitro group, a fluoro group, a chloro group, a bromo group, an iodo group, a trifluoromethyl group, a cyano group, a carbon-oxygen double bond, a carbon-sulfur double bond, an aromatic hydrocarbon group having 6 to 20 carbon atoms, a heteroaromatic group having 3 to 20 carbon atoms, and an aliphatic hydrocarbon group having 1 to 15 carbon atoms, as described in any of [1] to [5]. [7] R in the formula (1) 2 and R 3 are each independently a methylene group or an ethylene group, the methylene group and the ethylene group may each be substituted with one or more groups selected from a cyano group, a fluoro group, a methyl group, a cyclohexyl group, an adamantyl group, a trifluoromethyl group, a phenyl group, a pyridyl group, a pyrimidyl group, a pyrazyl group, a triazyl group, a quinolyl group, an isoquinolyl group, a naphthyl group, a phenanthryl group, and an anthryl group, the photoelectric conversion element according to any one of [1] to [6]. [8] R in the formula (1) 2 and R 3 are each independently a methylene group or an ethylene group, substituted with one or more groups selected from a cyano group, a fluoro group, a methyl group, a cyclohexyl group, an adamantyl group, a trifluoromethyl group, a phenyl group, a pyridyl group, a pyrimidyl group, a pyrazyl group, a triazyl group, a quinolyl group, an isoquinolyl group, a naphthyl group, a phenanthryl group, and an anthryl group, the photoelectric conversion element according to any one of [1] to [7]. [8-2] R in the formula (1) 2 and R 3 are each independently a methylene group or an ethylene group, the methylene group and the ethylene group each independently have no substituent, the photoelectric conversion element according to any one of [1] to [7]. [9] An electron transport material containing a compound represented by the following formula (2). [Chemical formula] (In formula (2), R 4 and R 5 each independently represent an aliphatic hydrocarbon group having 1 to 15 carbon atoms, The aliphatic hydrocarbon group may be substituted with one or more groups selected from hydroxyl groups, carboxyl groups, formyl groups, nitro groups, fluoro groups, chloro groups, bromo groups, iodo groups, trifluoromethyl groups, cyano groups, carbon-oxygen double bonds, carbon-sulfur double bonds, aromatic hydrocarbon groups having 6 to 20 carbon atoms, heteroaromatic groups having 3 to 20 carbon atoms, and aliphatic hydrocarbon groups having 1 to 15 carbon atoms. The aliphatic hydrocarbon group may be linear, branched, or cyclic, and m and n each independently represent 1, 2, or 3. Ring B represents an aromatic hydrocarbon ring with 6 to 20 carbon atoms, or a heteroaromatic ring with 4 to 20 carbon atoms. The aromatic hydrocarbon ring and the heteroaromatic ring may each be a monoring, a fused ring, or a linked ring, and the linked ring may be bonded by methylene groups substituted with trifluoromethyl groups. The aromatic hydrocarbon ring and the heteroaromatic ring may be substituted with one or more groups selected from a hydroxyl group, a carboxyl group, a formyl group, a nitro group, a cyano group, a fluoro group, a chloro group, a bromo group, an iodo group, a fluoroalkyl group having 1 to 10 carbon atoms, a fluoroalkoxy group having 1 to 10 carbon atoms, an alkyl group having 1 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 20 carbon atoms, and a heteroaromatic group having 3 to 20 carbon atoms. The aromatic hydrocarbon ring and the heteroaromatic ring may be bonded to the aromatic hydrocarbon group or the heteroaromatic group by one or more selected from an oxygen atom, a carbonyl group, and a thiocarbonyl group. The aromatic hydrocarbon group and the heteroaromatic group may each be a monocyclic, fused, or linked ring.

[10] The electron transport material described in [9], which is a material for photoelectric conversion elements.

[11] An electron transport material according to [9] or

[10] , which is a material for an imaging photoelectric conversion element.

[12] The electron transport material according to any one of [9] to

[11] , wherein the ring B in formula (2) may be substituted with one or more of the following (B-1) to (B-17). [ka]

[13] The electron transport material according to

[12] , wherein ring B in formula (2) may be substituted with one or more of the groups described above (B-1) or (B-2).

[14] R in equation (2) above 4 and R 5 However, each is independently a methylene group or an ethylene group, The methylene group and the ethylene group may be substituted with one or more groups selected from a hydroxyl group, a carboxyl group, a formyl group, a nitro group, a fluoro group, a chloro group, a bromo group, an iodo group, a trifluoromethyl group, a cyano group, a carbon-oxygen double bond, a carbon-sulfur double bond, an aromatic hydrocarbon group having 6 to 20 carbon atoms, a heteroaromatic group having 3 to 20 carbon atoms, and an aliphatic hydrocarbon group having 1 to 15 carbon atoms, as described in any of [9] to

[13] .

[15] R in equation (2) above 4 and R 5 However, each is independently a methylene group or an ethylene group, The methylene group and the ethylene group may be substituted with one or more groups selected from cyano, fluoro, methyl, cyclohexyl, adamantyl, trifluoromethyl, phenyl, pyridyl, pyrimidyl, pyrazyl, triazyl, quinolyl, isoquinolyl, naphthyl, phenanthryl, and anthryl groups, as described in any of [9] to

[14] .

[16] R in equation (2) above 4 and R 5 However, each is independently a methylene group or an ethylene group, An electron transport material according to any one of [9] to

[15] , which is substituted with one or more groups selected from a cyano group, a fluoro group, a methyl group, a cyclohexyl group, an adamantyl group, a trifluoromethyl group, a phenyl group, a pyridyl group, a pyrimidyl group, a pyrazyl group, a triazyl group, a quinolyl group, an isoquinolyl group, a naphthyl group, a phenanthryl group, and an anthryl group. [16-2] R in equation (2) above 4 and R5 However, each is independently a methylene group or an ethylene group, The methylene group and the ethylene group are each independently without substituents, as described in any of [9] to

[15] . [Effects of the Invention]

[0008] The present invention provides a photoelectric conversion element and an electron transport material that can improve electron transport capability or reduce energy barriers with adjacent layers. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic cross-sectional view showing an example of a stacked configuration of a photoelectric conversion element according to the present invention. [Modes for carrying out the invention]

[0010] The photoelectric conversion element of the present invention is an element that converts light energy into electrical energy or electrical signals, and includes image sensors, light sensors, solar cells, etc. The photoelectric conversion element of the present invention can be applied to organic electronic elements, including organic electroluminescent elements (organic EL elements).

[0011] The photoelectric conversion element of the present invention includes a first electrode, a second electrode, and a light-receiving layer and an organic layer disposed between the first electrode and the second electrode. The organic layer includes an electron transport layer. The electron transport layer contains a compound represented by the following formula (1) (hereinafter also referred to as the compound represented by formula (1)).

[0012] [ka] A detailed explanation of the compound represented by formula (1) above will be given later. Here, the electron transport layer has the role of transporting electrons and contains an electron transport material. The compound represented by formula (1) above can be used as an electron transport material, although this is not a limiting factor.

[0013] The following describes an example of the element configuration of a photoelectric conversion element.

[0014] <Configuration of photoelectric conversion element> The photoelectric conversion element according to the present invention includes a first electrode, a second electrode, and a light-receiving layer and an organic layer disposed between the first electrode and the second electrode, the organic layer including an electron transport layer. In the present invention, the compound represented by formula (1) above can be used as the electron transport material contained in the electron transport layer. The electron transport layer is preferably adjacent to the second electrode. Photoelectric conversion elements may include other layers. Examples of other layers include, but are not limited to, those commonly used in photoelectric conversion elements. These include, but are not limited to, light-receiving layers, hole transport layers, hole transport-enhancing layers, hole-blocking layers, electron-blocking layers, and buffer layers.

[0015] In the photoelectric conversion element according to the present invention, for example, a first electrode, an electron transport layer, and a second electrode are stacked in this order. Furthermore, the photoelectric conversion element may have other layers interposed between, for example, the second electrode and the electron transport layer, such as a buffer layer.

[0016] In one embodiment, the photoelectric conversion element according to the present invention has a first electrode, a hole transport layer, a light-receiving layer, an electron transport layer, and a second electrode stacked in this order. In another embodiment, the photoelectric conversion element according to the present invention has a first electrode, a hole transport enhancement layer, a hole transport layer, a light-receiving layer, an electron transport layer, and a second electrode stacked in this order. The above layers may be stacked adjacent to each other, or other layers may be interposed between any of the above layers.

[0017] The photoelectric conversion element may be subjected to light from either the first electrode side or the second electrode side, and either the first electrode or the second electrode may be a transparent electrode. For example, it may have a structure in which a transparent electrode (second electrode), electron transport layer, light receiving layer, hole transport layer, hole transport enhancement layer, and metal electrode (first electrode) are stacked in that order, or it may have a structure in which a transparent electrode (first electrode), hole transport enhancement layer, hole transport layer, light receiving layer, electron transport layer, and metal electrode (second electrode) are stacked in that order. Furthermore, both the first electrode and the second electrode may be transparent electrodes.

[0018] Next, the compound represented by formula (1) in the photoelectric conversion element of the present invention will be described.

[0019] <Compound represented by formula (1)> The organic layer in the photoelectric conversion element of the present invention contains a compound represented by the following formula (1).

[0020] [ka]

[0021] In formula (1), R 2 and R 3 Each of these independently represents an aliphatic hydrocarbon group having 1 to 15 carbon atoms. The aliphatic hydrocarbon group may be a saturated aliphatic hydrocarbon group or an unsaturated aliphatic hydrocarbon group. Furthermore, the aliphatic hydrocarbon group may be a group formed by combining a saturated aliphatic hydrocarbon group and an unsaturated aliphatic hydrocarbon group. Examples of saturated aliphatic hydrocarbon groups include alkylene groups having 1 to 15 carbon atoms. In this specification, "alkylene group" refers to a divalent group formed by the loss of two hydrogen atoms from aliphatic hydrocarbons (alkanes) such as methane, ethane, and propane, and generally has the -C x H 2x It is represented by - (where x is a positive integer). Examples of unsaturated aliphatic hydrocarbon groups include alkenylene groups having 2 to 15 carbon atoms and alkylylene groups having 2 to 15 carbon atoms. The unsaturated aliphatic hydrocarbon group may have two or more carbon-carbon double bonds, two or more carbon-carbon triple bonds, or both carbon-carbon double bonds and carbon-carbon triple bonds. In this specification, "alkenylene group" refers to a divalent group that is produced when two hydrogen atoms are lost from an aliphatic hydrocarbon having one carbon-carbon double bond in its molecule, such as ethylene, and is generally -C x H 2x-2 It is represented by - (where x is an integer greater than or equal to 2). In this specification, "alkynylene group" refers to a divalent group that is produced when two hydrogen atoms are lost from an aliphatic hydrocarbon having one carbon-carbon triple bond in its molecule, such as acetylene, and is generally -C x H 2x-4 It is represented by - (where x is an integer greater than or equal to 2).

[0022] Examples of alkylene groups having 1 to 15 carbon atoms include methylene, ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, cyclopropylene, cyclobutylene, cyclopentylene, cyclohexylene, adamantylene, tert-butylene, and isopropylene. Examples of alkenylene groups having 2 to 15 carbon atoms include etenylene (-CH=CH-), propenylene (-CH2CH=CH-), and butenylene (-CH2CH=CHCH2-). Here, "=" represents a carbon-carbon double bond. Examples of alkynylene groups having 2 to 15 carbon atoms include ethynylene (-C≡C-), propynylene (-CH2C≡C-), and butynylene (-CH2C≡CCH2-). Here, "≡" represents a carbon-carbon triple bond. As the aliphatic hydrocarbon group having 1 to 15 carbon atoms, alkylene groups having 1 to 15 carbon atoms are preferred in terms of compound stability, methylene groups or ethylene groups are more preferred in terms of ease of synthesis, and methylene groups are even more preferred in terms of superior device performance.

[0023] Aliphatic hydrocarbon groups having 1 to 15 carbon atoms may be substituted with one or more groups selected from hydroxyl groups, carboxyl groups, formyl groups, nitro groups, fluoro groups, chloro groups, bromo groups, iodo groups, trifluoromethyl groups, cyano groups, carbon-oxygen double bonds, carbon-sulfur double bonds, aromatic hydrocarbon groups having 6 to 20 carbon atoms, heteroaromatic groups having 3 to 20 carbon atoms, and aliphatic hydrocarbon groups having 1 to 15 carbon atoms. The aliphatic hydrocarbon group having 1 to 15 carbon atoms may be linear, branched, or cyclic.

[0024] In formula (1), m represents 1, 2, or 3. m is preferably 1 or 2 because it is easy to synthesize, and more preferably 1 because the compound is stable. In formula (1), n ​​represents 1, 2, or 3. n is preferably 1 or 2 because it is easy to synthesize, and more preferably 1 because the compound is stable.

[0025] Examples of aromatic hydrocarbon groups having 6 to 20 carbon atoms include phenyl, naphthyl, anthryl, phenantrenyl, pyrenyl, perilenyl, triphenylenyl, tetracenyl, chrysenyl, fluorenyl, 9,9-dimethylfluorenyl, 9,9-diphenylfluorenyl, spirobifluorenyl, biphenylyl, terphenyl, naphthylphenyl, phenylnaphthyl, binaphthyl, anthrylphenyl, phenylanthryl, and naphthylanthryl groups. Among the aromatic hydrocarbon groups having 6 to 20 carbon atoms, the phenyl or naphthyl group is preferred in terms of superior device performance. Examples of heteroaromatic groups having 3 to 20 carbon atoms include pyridyl, pyrazyl, pyrimidyl, triazyl, quinolyl, isoquinolyl, quinoxalyl, quinazolinyl, pyridopyrimidinyl, benzoquinolyl, benzoisoquinolyl, phenantrolyl, phenanthridyl, acridyl, phenazinyl, phenoxazinyl, phenothiazinyl, benzoquinoxalyl, hexaazatriphenylenyl, thienyl, furyl, benzothienyl, benzofuryl, isobenzofuryl, dibenzothiophenyl, dibenzofuranyl, benzoxazolyl, pyrrole, indole, isoindole, indolidinyl, purine, imidazolyl, carbazolyl, thiazolyl, and thiadiazolyl groups. As heteroaromatic groups having 3 to 20 carbon atoms, pyridyl, pyrazyl, pyrimidyl, quinolyl, or isoquinolyl groups are preferred in terms of their excellent device performance, and pyridyl or pyrazyl groups are even more preferred in terms of ease of synthesis.

[0026] In formula (1), ring A represents an aromatic hydrocarbon ring having 6 to 20 carbon atoms, or a heteroaromatic ring having 4 to 20 carbon atoms. Aromatic hydrocarbon rings having 6 to 20 carbon atoms may be monocyclic, fused, or linked rings. Heterocyclic aromatic rings having 4 to 20 carbon atoms may be monocyclic, fused, or linked rings. The aforementioned linking ring may be bonded by methylene groups substituted with trifluoromethyl groups. The aforementioned fused ring may be a fused ring of aromatic hydrocarbon rings, a fused ring of an aromatic hydrocarbon ring and a heteroaromatic ring, or a fused ring of heteroaromatic rings. The linking ring may be a linking ring of aromatic hydrocarbon rings, a linking ring of an aromatic hydrocarbon ring and a heteroaromatic ring, or a linking ring of heteroaromatic rings.

[0027] Examples of aromatic hydrocarbon rings having 6 to 20 carbon atoms include benzene rings, naphthalene rings, anthracene rings, phenanthrene rings, pyrene rings, perylene rings, triphenylene rings, tetracene rings, chrysene rings, fluorene rings, 9,9-dimethylfluorene rings, 9,9-diphenylfluorene rings, spirobifluorene rings, biphenyl rings, binaphthyl rings, and terphenyl rings. Among the aromatic hydrocarbon rings having 6 to 20 carbon atoms, benzene rings, naphthyl rings, or perylene rings are preferred because they are easy to synthesize, and benzene rings or naphthalene rings are more preferred because they have excellent device performance.

[0028] Examples of heteroaromatic rings having 4 to 20 carbon atoms include pyridine rings, pyrazine rings, pyrimidine rings, quinoline rings, isoquinoline rings, quinoxaline rings, quinazoline rings, benzoquinoline rings, benzoisoquinoline rings, phenanthroline rings, phenanthoridine rings, acridine rings, phenazine rings, phenoxazine rings, phenothiazine rings, benzoquinoxaline rings, thienyl rings, furyl rings, benzothiophene rings, benzofuran rings, isobenzofuran rings, dibenzothiophene rings, dibenzofuran rings, benzoxazole rings, pyrrole rings, indole rings, isoindole rings, and carbazolyl rings. Among the heteroaromatic rings having 4 to 20 carbon atoms, pyridine rings or pyrazine rings are preferred in terms of their excellent device performance.

[0029] The C6-C20 aromatic hydrocarbon ring may be substituted with one or more groups selected from a hydroxyl group, carboxyl group, formyl group, nitro group, cyano group, fluoro group, chloro group, bromo group, iodo group, C1-C10 fluoroalkyl group, C1-C10 fluoroalkoxy group, C1-C10 alkyl group, C6-C20 aromatic hydrocarbon group, and C3-C20 heteroaromatic group. A C6-C20 aromatic hydrocarbon ring may be bonded to a C6-C20 aromatic hydrocarbon group or a C3-C20 heteroaromatic group by one or more selected from an oxygen atom, a carbonyl group, and a thiocarbonyl group.

[0030] The heteroaromatic ring having 4 to 20 carbon atoms may be substituted with one or more groups selected from a hydroxyl group, a carboxyl group, a formyl group, a nitro group, a cyano group, a fluoro group, a chloro group, a bromo group, an iodo group, a fluoroalkyl group having 1 to 10 carbon atoms, a fluoroalkoxy group having 1 to 10 carbon atoms, an alkyl group having 1 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 20 carbon atoms, and a heteroaromatic group having 3 to 20 carbon atoms. A heteroaromatic ring having 4 to 20 carbon atoms may be bonded to an aromatic hydrocarbon group having 6 to 20 carbon atoms or a heteroaromatic group having 3 to 20 carbon atoms by one or more selected from an oxygen atom, a carbonyl group, and a thiocarbonyl group.

[0031] Examples of fluoroalkyl groups having 1 to 10 carbon atoms include fluoromethyl, difluoromethyl, trifluoromethyl, fluoroethyl, difluoroethyl, trifluoroethyl, tetrafluoroethyl, perfluoroethyl, fluoropropyl, perfluoropropyl, perfluorobutyl, perfluoropentyl, perfluorohexyl, perfluoroheptyl, and perfluorooctyl groups.

[0032] Examples of fluoroalkoxy groups having 1 to 10 carbon atoms include fluoromethoxy, difluoromethoxy, trifluoromethoxy, fluoroethoxy, difluoroethoxy, trifluoroethoxy, tetrafluoroethoxy, perfluoroethoxy, fluoropropoxy, perfluoropropoxy, perfluorobutoxy, perfluoropentyloxy, perfluorohexyloxy, perfluoroheptyloxy, and perfluorooctyloxy groups.

[0033] Examples of alkyl groups having 1 to 10 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, and n-decyl groups.

[0034] -R in equation (1)2 -(CN) m and -R 3 -(CN) n As such, (R-1) to (R-56) below can be cited as preferred examples, independently of each other.

[0035] [ka]

[0036] [ka] [ka]

[0037] Among the above (R-1) to (R-56), (R-1), (R-2), (R-8), or (R-26) are more preferred, and (R-1) or (R-8) are even more preferred in that they are easy to synthesize.

[0038] Also, R in equation (1) 2 and R 3 Independently, unsubstituted methylene groups, cyano-substituted methylene groups, or unsubstituted ethylene groups are preferred, and unsubstituted methylene groups or unsubstituted ethylene groups are more preferred in terms of ease of synthesis.

[0039] The methylene group and ethylene group may be substituted with one or more groups selected from hydroxyl group, carboxyl group, formyl group, nitro group, fluoro group, chloro group, bromo group, iodo group, trifluoromethyl group, cyano group, carbon-oxygen double bond, carbon-sulfur double bond, C6-C20 aromatic hydrocarbon group, C3-C20 heteroaromatic group, and C1-C15 aliphatic hydrocarbon group. Furthermore, the methylene group and the ethylene group may be substituted with one or more groups selected from cyano, fluoro, methyl, cyclohexyl, adamantyl, trifluoromethyl, phenyl, pyridyl, pyrimidyl, pyrazyl, triazyl, quinolyl, isoquinolyl, naphthyl, phenanthryl, and anthryl groups.

[0040] Examples of ring A in formula (1) include (A-1) to (A-17) listed below. These (A-1) to (A-17) may be substituted with one or more groups selected from a hydroxyl group, a carboxyl group, a formyl group, a nitro group, a cyano group, a fluoro group, a chloro group, a bromo group, an iodo group, a fluoroalkyl group having 1 to 10 carbon atoms, a fluoroalkoxy group having 1 to 10 carbon atoms, an alkyl group having 1 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 20 carbon atoms, and a heteroaromatic group having 3 to 20 carbon atoms. Furthermore, these (A-1) to (A-17) may be bonded to an aromatic hydrocarbon group having 6 to 20 carbon atoms or a heteroaromatic group having 3 to 20 carbon atoms by one or more selected from an oxygen atom, a carbonyl group, and a thiocarbonyl group.

[0041] [ka]

[0042] Of the above (A-1) to (A-17), (A-1), (A-2), (A-4), (A-5), (A-6), (A-8), (A-9), or (A-10) are preferred, and (A-1), (A-2), (A-8), (A-9), or (A-10) are more preferred in that they have sufficient acceptability and are expected to perform well. Furthermore, (A-1) or (A-2) are preferred in that they are easy to synthesize, and (A-1) is more preferred in that the raw materials are easily available.

[0043] The photoelectric conversion element of the present invention is not particularly limited, but can be applied to solar cells, photodiodes, photoelectric conversion elements for image sensors, and the like. In particular, the photoelectric conversion element of the present invention is preferably used for image sensors.

[0044] The compound represented by formula (1) is used as part of a photoelectric conversion element (organic electronic element). While not particularly limited, it is preferably used as part of an electron transport layer.

[0045] Examples of electron transport materials include materials containing compounds represented by the following formula (2).

[0046] [ka]

[0047] In formula (2), R 4 and R 5 Each of these independently represents an aliphatic hydrocarbon group having 1 to 15 carbon atoms. The aliphatic hydrocarbon group in formula (2) is the same as the aliphatic hydrocarbon group in formula (1) described above. As the aliphatic hydrocarbon group having 1 to 15 carbon atoms, alkylene groups having 1 to 15 carbon atoms are preferred in terms of compound stability, methylene groups or ethylene groups are more preferred in terms of ease of synthesis, and methylene groups are even more preferred in terms of superior device performance. Aliphatic hydrocarbon groups having 1 to 15 carbon atoms may be substituted with one or more groups selected from hydroxyl groups, carboxyl groups, formyl groups, nitro groups, fluoro groups, chloro groups, bromo groups, iodo groups, trifluoromethyl groups, cyano groups, carbon-oxygen double bonds, carbon-sulfur double bonds, aromatic hydrocarbon groups having 6 to 20 carbon atoms, heteroaromatic groups having 3 to 20 carbon atoms, and aliphatic hydrocarbon groups having 1 to 15 carbon atoms. The aliphatic hydrocarbon group having 1 to 15 carbon atoms may be linear, branched, or cyclic. In formula (2), m represents 1, 2, or 3. m is preferably 1 or 2 because it is easy to synthesize, and more preferably 1 because the compound is stable. In formula (2), n represents 1, 2, or 3. n is preferably 1 or 2 because it is easy to synthesize, and more preferably 1 because the compound is stable. In formula (2), ring B represents an aromatic hydrocarbon ring having 6 to 20 carbon atoms, or a heteroaromatic ring having 4 to 20 carbon atoms. Aromatic hydrocarbon rings having 6 to 20 carbon atoms may be monocyclic, fused, or linked rings. Heterocyclic aromatic rings having 4 to 20 carbon atoms may be monocyclic, fused, or linked rings. The aforementioned linking ring may be bonded by methylene groups substituted with trifluoromethyl groups.

[0048] Examples of aromatic hydrocarbon rings having 6 to 20 carbon atoms include aromatic hydrocarbon rings similar to those in the compound represented by formula (1) above. The C6-C20 aromatic hydrocarbon ring may be substituted with one or more groups selected from a hydroxyl group, carboxyl group, formyl group, nitro group, cyano group, fluoro group, chloro group, bromo group, iodo group, C1-C10 fluoroalkyl group, C1-C10 fluoroalkoxy group, C1-C10 alkyl group, C6-C20 aromatic hydrocarbon group, and C3-C20 heteroaromatic group. A C6-C20 aromatic hydrocarbon ring may be bonded to a C6-C20 aromatic hydrocarbon group or a C3-C20 heteroaromatic group by one or more selected from an oxygen atom, a carbonyl group, and a thiocarbonyl group.

[0049] Examples of heteroaromatic rings having 4 to 20 carbon atoms include heteroaromatic rings similar to those in the compound represented by formula (1) above. The heteroaromatic ring having 4 to 20 carbon atoms may be substituted with one or more groups selected from a hydroxyl group, a carboxyl group, a formyl group, a nitro group, a cyano group, a fluoro group, a chloro group, a bromo group, an iodo group, a fluoroalkyl group having 1 to 10 carbon atoms, a fluoroalkoxy group having 1 to 10 carbon atoms, an alkyl group having 1 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 20 carbon atoms, and a heteroaromatic group having 3 to 20 carbon atoms. A heteroaromatic ring having 4 to 20 carbon atoms may be bonded to an aromatic hydrocarbon group having 6 to 20 carbon atoms or a heteroaromatic group having 3 to 20 carbon atoms by one or more selected from an oxygen atom, a carbonyl group, and a thiocarbonyl group.

[0050] Examples of aromatic hydrocarbon groups having 6 to 20 carbon atoms include those similar to the aromatic hydrocarbon groups having 6 to 20 carbon atoms in the compound shown in formula (1) above. The aromatic hydrocarbon group having 6 to 20 carbon atoms may be a monocyclic, fused, or linked ring.

[0051] Examples of heteroaromatic groups having 3 to 20 carbon atoms include the same heteroaromatic groups as those in the compound shown in formula (1) above. The heteroaromatic group having 3 to 20 carbon atoms may be a monocyclic, fused, or linked ring.

[0052] Examples of fluoroalkyl groups having 1 to 10 carbon atoms include those similar to the fluoroalkyl groups having 2 to 10 carbon atoms in the compound represented by formula (1) described above.

[0053] Examples of fluoroalkoxy groups having 1 to 10 carbon atoms include fluoroalkoxy groups similar to those in the compound represented by formula (1) described above.

[0054] Examples of alkyl groups having 1 to 10 carbon atoms include those similar to the alkyl groups having 1 to 10 carbon atoms in the compound represented by formula (1) above.

[0055] -R in equation (2) 4 -(CN) m and -R 5 -(CN) nAs examples, (R-1) to (R-56) can be listed independently as preferred examples. Among these, (R-1), (R-2), (R-8), or (R-26) are more preferred, (R-1), (R-8), or (R-26) are even more preferred, and (R-1) or (R-26) are particularly preferred in terms of ease of synthesis. Also, R in equation (2) 4 and R 5 Independently, the following are preferred: an unsubstituted methylene group, a methylene group substituted with a cyano group, an aromatic hydrocarbon group, a heteroaromatic group, or an aliphatic hydrocarbon group, or an unsubstituted ethylene group; more preferably, an unsubstituted methylene group, a methylene group substituted with a cyano group, a methylene group substituted with a phenyl group, a methylene group substituted with a cyanophenyl group, a methylene group substituted with a pyridyl group, or an unsubstituted ethylene group; and even more preferably, an unsubstituted methylene group, an unsubstituted ethylene group, or a methylene group substituted with a phenyl group, as these are easier to synthesize.

[0056] The methylene group and ethylene group may be substituted with one or more groups selected from hydroxyl group, carboxyl group, formyl group, nitro group, fluoro group, chloro group, bromo group, iodo group, trifluoromethyl group, cyano group, carbon-oxygen double bond, carbon-sulfur double bond, C6-C20 aromatic hydrocarbon group, C3-C20 heteroaromatic group, and C1-C15 aliphatic hydrocarbon group. Furthermore, the methylene group and the ethylene group may be substituted with one or more groups selected from cyano, fluoro, methyl, cyclohexyl, adamantyl, trifluoromethyl, phenyl, pyridyl, pyrimidyl, pyrazyl, triazyl, quinolyl, isoquinolyl, naphthyl, phenanthryl, and anthryl groups.

[0057] Examples of ring B in formula (2) include (B-1) to (B-17) listed below. These (B-1) to (B-17) may be substituted with one or more groups selected from a hydroxyl group, a carboxyl group, a formyl group, a nitro group, a cyano group, a fluoro group, a chloro group, a bromo group, an iodo group, a fluoroalkyl group having 1 to 10 carbon atoms, a fluoroalkoxy group having 1 to 10 carbon atoms, an alkyl group having 1 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 20 carbon atoms, and a heteroaromatic group having 3 to 20 carbon atoms. Furthermore, these (B-1) to (B-17) may be bonded to an aromatic hydrocarbon group having 6 to 20 carbon atoms or a heteroaromatic group having 3 to 20 carbon atoms by one or more selected from an oxygen atom, a carbonyl group, and a thiocarbonyl group.

[0058] [ka]

[0059] Of the above (B-1) to (B-17), (B-1), (B-2), (B-4), (B-5), (B-6), (B-8), (B-9), or (B-10) are preferred, with (B-1), (B-2), (B-8), (B-9), or (B-10) being more preferred in that they have sufficient acceptability and are expected to perform well. Furthermore, (B-1) or (B-2) are preferred in that they are easy to synthesize, and (B-1) is more preferred in that the raw materials are easily available.

[0060] The compound represented by formula (2) is used as an electron transport material. Among these, it is preferably a material for an imaging photoelectric conversion element.

[0061] A more preferred embodiment of the compounds represented by formula (1) and formula (2) above is the compound represented by the following formula (X-1). [ka] (In formula (X-1), ring G is selected from the group consisting of (G-1), (G-2), (G-8), (G-9), and (G-10) below, R 11, R 12 Each of these independently represents a methylene group or an ethylene group, which may be substituted with one or more groups selected from the group consisting of a cyano group, a C6 aromatic hydrocarbon group, a heteroaromatic group (e.g., a pyridyl group, pyrimidyl group, quinolyl group, isoquinolyl group, etc.), and aliphatic hydrocarbon groups having 1 to 6 carbon atoms (which may be linear, branched, or cyclic aliphatic hydrocarbon groups). [ka] )

[0062] Examples of imide compounds that can improve electron transport capability and are used in the photoelectric conversion element or electron transport material of the present invention include imide compounds represented by the following formula (3) or formula (4).

[0063] [ka]

[0064] [ka]

[0065] In formula (3), T 1 and T 2 This represents a hydrogen atom, a hydroxyl group, a carboxyl group, a formyl group, a nitro group, an amino group, a cyano group, a fluoro group, a chloro group, a bromo group, an iodo group, a fluoroalkyl group having 1 to 10 carbon atoms, a fluoroalkoxy group having 1 to 10 carbon atoms, an alkyl group having 1 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 20 carbon atoms, a heteroaromatic group having 3 to 20 carbon atoms, or a substituent formed by combining two or more of these. Here, "substituents formed by combining two or more of these" refers, for example, to substituents in which one or more hydrogen atoms of an aromatic hydrocarbon group having 6 to 20 carbon atoms are replaced by a cyano group. In formula (3), R 6 and R 7 Each of these independently represents an aliphatic hydrocarbon group having 1 to 15 carbon atoms. The aliphatic hydrocarbon group in formula (3) is the same as the aliphatic hydrocarbon group in formula (1) described above. As the aliphatic hydrocarbon group having 1 to 15 carbon atoms, alkylene groups having 1 to 15 carbon atoms are preferred in terms of compound stability, methylene groups or ethylene groups are more preferred in terms of ease of synthesis, and methylene groups are even more preferred in terms of superior device performance. Aliphatic hydrocarbon groups having 1 to 15 carbon atoms may be substituted with one or more groups selected from hydroxyl groups, carboxyl groups, formyl groups, nitro groups, fluoro groups, chloro groups, bromo groups, iodo groups, trifluoromethyl groups, cyano groups, carbon-oxygen double bonds, carbon-sulfur double bonds, aromatic hydrocarbon groups having 6 to 20 carbon atoms, heteroaromatic groups having 3 to 20 carbon atoms, and aliphatic hydrocarbon groups having 1 to 15 carbon atoms. The aliphatic hydrocarbon group having 1 to 15 carbon atoms may be linear, branched, or cyclic. In formula (3), m represents 1, 2, or 3. m is preferably 1 or 2 because it is easy to synthesize, and more preferably 1 because the compound is stable. In formula (3), n represents 1, 2, or 3. n is preferably 1 or 2 because it is easy to synthesize, and more preferably 1 because the compound is stable.

[0066] Examples of aromatic hydrocarbon groups having 6 to 20 carbon atoms include those similar to the aromatic hydrocarbon groups having 6 to 20 carbon atoms in the compound shown in formula (1) above. The aromatic hydrocarbon group having 6 to 20 carbon atoms may be a monocyclic, fused, or linked ring.

[0067] Examples of heteroaromatic groups having 3 to 20 carbon atoms include the same heteroaromatic groups as those in the compound shown in formula (1) above. The heteroaromatic group having 3 to 20 carbon atoms may be a monocyclic, fused, or linked ring.

[0068] Examples of fluoroalkyl groups having 1 to 10 carbon atoms include those similar to the fluoroalkyl groups having 2 to 10 carbon atoms in the compound represented by formula (1) described above.

[0069] Examples of fluoroalkoxy groups having 1 to 10 carbon atoms include fluoroalkoxy groups similar to those in the compound represented by formula (1) described above.

[0070] Examples of alkyl groups having 1 to 10 carbon atoms include those similar to the alkyl groups having 1 to 10 carbon atoms in the compound represented by formula (1) above.

[0071] In formula (4), T 3 ~T 6 Each of these independently represents a hydrogen atom, a hydroxyl group, a carboxyl group, a formyl group, a nitro group, an amino group, a cyano group, a fluoro group, a chloro group, a bromo group, an iodo group, a fluoroalkyl group having 1 to 10 carbon atoms, a fluoroalkoxy group having 1 to 10 carbon atoms, an alkyl group having 6 to 20 carbon atoms, an aromatic hydrocarbon group having 3 to 20 carbon atoms, or a substituent formed by combining two or more of these. In formula (4), R 8 and R 9 Each of these independently represents an aliphatic hydrocarbon group having 1 to 15 carbon atoms. The aliphatic hydrocarbon group in formula (4) is the same as the aliphatic hydrocarbon group in formula (1) described above. As the aliphatic hydrocarbon group having 1 to 15 carbon atoms, alkylene groups having 1 to 15 carbon atoms are preferred in terms of compound stability, methylene groups or ethylene groups are more preferred in terms of ease of synthesis, and methylene groups are even more preferred in terms of superior device performance. Aliphatic hydrocarbon groups having 1 to 15 carbon atoms may be substituted with one or more groups selected from hydroxyl groups, carboxyl groups, formyl groups, nitro groups, fluoro groups, chloro groups, bromo groups, iodo groups, trifluoromethyl groups, cyano groups, carbon-oxygen double bonds, carbon-sulfur double bonds, aromatic hydrocarbon groups having 6 to 20 carbon atoms, heteroaromatic groups having 3 to 20 carbon atoms, and aliphatic hydrocarbon groups having 1 to 15 carbon atoms. The aliphatic hydrocarbon group having 1 to 15 carbon atoms may be linear, branched, or cyclic. In formula (4), m represents 1, 2, or 3. m is preferably 1 or 2 because it is easy to synthesize, and more preferably 1 because the compound is stable. In formula (4), n represents 1, 2, or 3. n is preferably 1 or 2 because it is easy to synthesize, and more preferably 1 because the compound is stable. In equation (4), T 3 =T 4 =T 5 =T 6 =When it is a hydrogen atom and m=n=1, R 8 =R 9 = It does not become an unsubstituted methylene group. In equation (4), T 3 =T 4 =T 5 =T 6 =When it is a hydrogen atom and m=n=1, R 8 =R 9 = It does not become a methylene group substituted with an isobutyl group. In equation (4), T 3 =T 4 =T 5 =T 6 =When it is a hydrogen atom and m=n=1, R 8 =R 9 = It does not become an unsubstituted ethylene group.

[0072] Examples of aromatic hydrocarbon groups having 6 to 20 carbon atoms include those similar to the aromatic hydrocarbon groups having 6 to 20 carbon atoms in the compound shown in formula (1) above. The aromatic hydrocarbon group having 6 to 20 carbon atoms may be a monocyclic, fused, or linked ring.

[0073] Examples of heteroaromatic groups having 3 to 20 carbon atoms include the same heteroaromatic groups as those in the compound shown in formula (1) above. The heteroaromatic group having 3 to 20 carbon atoms may be a monocyclic, fused, or linked ring.

[0074] Examples of fluoroalkyl groups having 1 to 10 carbon atoms include those similar to the fluoroalkyl groups having 2 to 10 carbon atoms in the compound represented by formula (1) described above.

[0075] Examples of fluoroalkoxy groups having 1 to 10 carbon atoms include fluoroalkoxy groups similar to those in the compound represented by formula (1) described above.

[0076] Examples of alkyl groups having 1 to 10 carbon atoms include those similar to the alkyl groups having 1 to 10 carbon atoms in the compound represented by formula (1) above.

[0077] In equation (3) or equation (4), T 1 ~T 6 In terms of device performance, the following are preferred independently: a cyano group, a phenyl group (which may be substituted), a pyridyl group, a pyrazyl group, a triazyl group, a pyrimidyl group, a quinolyl group, an isoquinolyl group, a phenyloxy group, a pyridineoxy group, a pyrazineoxy group, a pyrimidineoxy group, and a triazineoxy group.

[0078] T 1 ~T 6Preferred specific examples include, independently, hydrogen atom, hydroxyl group, carboxyl group, formyl group, nitro group, amino group, cyano group, fluoro group, chloro group, bromo group, iodine group, trifluoromethyl group, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, adamantyl group, tert-butyl group, isopropyl group, phenyl group, cyanophenyl group, dicyanophenyl group, tricyanophenyl group, methylphenyl group, dimethylphenyl group. Group, trimethylphenyl group, fluorophenyl group, difluorophenyl group, trifluorophenyl group, perfluorophenyl group, biphenyl group, pyridylphenyl group, bispyridylphenyl group, trifluoromethylphenyl group, bistrifluoromethylphenyl group, pyridyl group, cyanopyridyl group, dicyanopyridyl group, tricyanopyridyl group, methylpyridyl group, dimethylpyridyl group, trimethylpyridyl group, fluoropyridyl group, difluoropyridyl group, trifluoropyridyl group, tetrafluoropyridyl group, phenylpyridyl group, diphenylpyridyl Group, bipyridyl group, terpyridyl group, trifluoromethylpyridyl group, bistrifluoromethylpyridyl group, pyrimidyl group, cyanopyridyl group, dicyanopyridyl group, tricyanopyridyl group, methylpyridyl group, dimethylpyridyl group, trimethylpyridyl group, fluoropyridyl group, difluoropyridyl group, trifluoropyridyl group, tetrafluoropyridyl group, phenylpyridyl group, diphenylpyridyl group, pyridylpyridyl group, bispyridylpyridyl group, trifluoromethylpyridyl group, bistrifluoromethylpyridyl A group, pyrazyl group, cyanopyrazyl group, dicyanopyrazyl group, tricyanopyrazyl group, methylpyrazyl group, dimethylpyrazyl group, trimethylpyrazyl group, fluoropyrazyl group, difluoropyrazyl group, trifluoropyrazyl group, tetrafluoropyrazyl group, phenylpyrazyl group, pyridylpyrazyl group, trifluoromethylpyrazyl group, bistrifluoromethylpyrazyl group, triazyl group, cyanotriazyl group, dicyanotriazyl group, methyltriazyl group, dimethyltriazyl group, fluorotriazyl group, difluorotriazyl group, phenyltriazyl group,Diphenyltriazyl group, pyridyltriazyl group, bispyridyltriazyl group, trifluoromethyltriazyl group, bistrifluoromethyltriazyl group, phenoxy group, biphenyloxy group, cyanophenyloxy group, dicyanophenyloxy group, naphthaleneoxy group, cyanonaphthaleneoxy group, pyridineoxy group, cyanopyridineoxy group, dicyanopyridineoxy group, phenylpyridineoxy group, diphenylpyridineoxy group, pyrazineoxy group, cyanopyridineoxy group, dicyanopyridineoxy group, phenylpyrazineoxy group, pyrimidineoxy group, cyanopyrimidineoxy group, dicyanopyrimidineoxy group, quinolyl Examples include the isoquinolyl group, quinoxalyl group, quinazolinyl group, pyridopyrimidinyl group, benzoquinolyl group, benzoisoquinolyl group, phenantrolyl group, phenanthridyl group, acridyl group, phenazinyl group, phenoxazinyl group, phenothiazinyl group, benzoquinoxalyl group, hexaazatriphenylenyl group, thienyl group, furyl group, benzothienyl group, benzofuryl group, isobenzofuryl group, dibenzothiophenyl group, dibenzofuranyl group, benzoxazolyl group, pyrrole group, indole group, isoindole group, indolidinyl group, purine group, imidazolyl group, carbazolyl group, thiazolyl group, thiadiazolyl group, etc.

[0079] For example, in equation (3), T 1 and T 2 is a hydrogen atom, n and m are 1, and R 6 and R 7 It is more preferable that each of these groups is independently substituted with one or more groups selected from the group consisting of a cyano group, a C6 aromatic hydrocarbon group, a heteroaromatic group (e.g., a pyridyl group, pyrimidyl group, quinolyl group, isoquinolyl group, etc.), and a C1-C6 aliphatic hydrocarbon group (which may be linear, branched, or cyclic aliphatic hydrocarbon groups).

[0080] Also, for example, in equation (4), T 3 and T 4 and T 5 and T 6is a hydrogen atom, n and m are 1, and R 8 and R 9 Each of these is a methylene group or ethylene group, which may be independently substituted with one or more groups selected from the group consisting of a cyano group, a C6 aromatic hydrocarbon group, a heteroaromatic group (e.g., pyridyl group, pyrimidyl group, quinolyl group, isoquinolyl group, etc.), and a C1-C6 aliphatic hydrocarbon group (which may be linear, branched, or cyclic aliphatic hydrocarbon groups), provided that R 8 and R 9 However, it is more preferable to exclude cases where both are unsubstituted methylene groups, both are unsubstituted ethylene groups, or both are methylene groups substituted with isobutyl groups.

[0081] Preferred examples of compounds represented by formula (1) include, for example, (C-1) to (C-262) below. However, the compounds of the present invention are not limited to these.

[0082] [ka]

[0083] [ka]

[0084] [ka]

[0085] [ka]

[0086] [ka]

[0087] [ka]

[0088]

change

[0089]

change

[0090]

change

[0091]

change

[0092]

change

[0093]

change

[0094]

change

[0095]

change

[0096]

change

[0097]

change

[0098]

change

[0099] [ka]

[0100] [ka]

[0101] [ka]

[0102] [ka]

[0103] [ka]

[0104] [ka]

[0105] [ka]

[0106] [Manufacturing method] The compound represented by formula (1) can be synthesized by known methods or combinations thereof. For example, a tetracarboxylic dianhydride represented by formula (5) can be reacted with an amine compound represented by formula (6) to obtain a compound represented by formula (7). Furthermore, the obtained compound represented by formula (7) can be reacted with an amine compound represented by formula (8) to synthesize the imide compound represented by formula (1). The imide compound represented by formula (1) can be synthesized in this two-step manner, or it can be synthesized in one step.

[0107] [ka] (In the formula, R 2 , R 3 m, n, and ring A represent the same definitions as in equation (1) above.

[0108] The reaction conditions in this manufacturing method can be similar to those for general imide formation reactions (e.g., Electrochemistry Communications 76 (2017) 47-50; Chem.Soc.Rev.,2008,37,331-342). Preferred reaction solvents include dimethylacetamide (DMAc), N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), methanol, ethanol, propanol, butanol, water, acetic acid, formic acid, trifluoromethanesulfonic acid, imidazole, and naphthalene, and mixed solvents combining several of these solvents may also be used. In addition, common acids, bases, or condensation accelerators can be added as reaction additives.

[0109] <<Effects of the compound represented by formula (1)>> The compound represented by formula (1) has a naphthalenediimide skeleton or a similar specific skeleton structure, and this strong acceptor skeleton gives it a deep LUMO level. This increases electron acceptivity, allowing it to accept electrons generated in the photodetector layer with a small energy barrier. Thus, because the compound represented by formula (1) has a deep LUMO level, it is expected that the exchange of holes between the hole transport layer and the electrode will be smoother. Furthermore, the compound represented by formula (1) is also characterized by a wide energy gap and a deep HOMO level. This is expected to suppress reverse charge injection from the electrode and improve hole blocking from the photodetector layer, and when used in an image sensor, for example, it is expected to reduce dark current or improve external quantum efficiency. Furthermore, because the compound represented by formula (1) has a naphthalenediimide skeleton or a similar specific skeleton structure, it can be expected to have thermal stability and high reduction resistance. In addition, because the compound represented by formula (1) has a cyano group bonded to the imide skeleton, strong interactions with the electrode and adjacent layers are expected, and it is anticipated that the exchange of electrons from the photodetector to the electrode will be smoother.

[0110] As described above, the inventors have found that the compound represented by formula (1) can be effectively used as an electron transport material to facilitate the exchange of electrons between the light-receiving layer and the electrode. They have also confirmed that the electron transport capability of a photoelectric conversion element is enhanced when the compound represented by formula (1) (electron transport material) is actually used. In other words, they have confirmed that the energy barrier when extracting carriers generated in the light-receiving layer to the electrode side in a photoelectric conversion element can be reduced by the compound represented by formula (1), which is the electron transport material of this application.

[0111] <Embodiment> For example, the following configuration (i) can be cited as a stacked configuration for the photoelectric conversion element of the present invention. (i): First electrode / Hole transport enhancement layer / Hole transport layer / Photodetector layer / Electron transport layer / Second electrode Furthermore, if the organic electronic element is, for example, an organic EL element, then in the configuration of (i) above, "light-receiving layer" can be read as "light-emitting layer".

[0112] Hereinafter, the photoelectric conversion element and organic EL element according to the present invention will be described in more detail, with reference to Figure 1, using the configuration described in (i) above as an example. Figure 1 is a schematic cross-sectional view showing an example of a stacked configuration of the photoelectric conversion element according to the present invention.

[0113] <<First Embodiment>> The photoelectric conversion element according to the first embodiment is an organic image sensor or optical sensor having the stacked configuration shown in Figure 1. The photoelectric conversion element 1 comprises a first electrode 11 (first electrode), a hole transport enhancement layer 12, a hole transport layer 13, a light receiving layer 14, an electron transport layer 15, and a second electrode 16 (second electrode) in this order. However, some of these layers may be omitted, or other layers may be added.

[0114] In the photoelectric conversion element 1 shown in Figure 1, light is incident from above the transparent first electrode 11 and received by the light-receiving layer 14. For convenience, Figure 1 shows the light incident from the side of the light-receiving layer 14. Furthermore, a voltage is applied to the photoelectric conversion element 1 so that the holes (positive and negative charges) generated by photoelectric conversion in the light-receiving layer 14 are moved to the first electrode 11 and the electrons are moved to the second electrode 16. That is, the first electrode 11 acts as a hole-collecting electrode and the second electrode 16 acts as an electron-collecting electrode. Note that the substrate provided on the upper surface of the first electrode 11 is omitted in Figure 1. There are no particular limitations on the substrate here, and examples include glass plates, quartz plates, plastic plates, etc. Also, in the configuration where light is incident from the substrate side, the substrate is transparent to the wavelength of light. The above layers will be described below.

[0115] [First electrode 11] A first electrode 11 or a second electrode 16 is provided on the substrate. In a photoelectric conversion element configured such that light passes through the first electrode 11 and enters the light-receiving layer 14, the first electrode is formed of a transparent material that transmits or substantially transmits the light. Here, "transmits light" means that the average transmittance is 80% or more, and "substantially transmits light" means that the average transmittance is 50% or more. In other words, in this specification, "transparent" means that the average transmittance is 50% or more.

[0116] The transparent material used for the first electrode 11 or the second electrode 16 is not particularly limited, but examples include indium tin oxide (ITO), indium zinc oxide (IZO), tin oxide, aluminum-doped tin oxide, magnesium-indium oxide, nickel-tungsten oxide, other metal oxides, metal nitrides such as gallium nitride, metal selenides such as zinc selenide, and metal sulfides such as zinc sulfide.

[0117] In the case of a photoelectric conversion element configured such that light enters the light-receiving layer 14 only from the second electrode 16 side, the transmission characteristics of the first electrode 11 are not important. Therefore, examples of materials that can be used for the first electrode in this case include gold, iridium, molybdenum, palladium, platinum, etc.

[0118] [Hole transport promotion layer 12] A hole transport accelerating layer 12 is provided between the first electrode 11 and the hole transport layer 13, which will be described later. The hole transport accelerating layer 12 is provided to promote hole transport from the hole transport layer 13 to the first electrode 11. The hole transport accelerating layer 12 may contain the compound shown in formula (1) above. It may also contain compounds other than the compound shown in formula (1). Examples of compounds that can be contained in the hole transport accelerating layer 12 include conventionally known hole transport materials, such as the compounds used in the hole transport layer 13 described later.

[0119] [Hole transport layer 13] A hole transport layer 13 is provided between the hole transport promoting layer 12 and the light receiving layer 14. The hole transport layer 13 has the role of transporting holes generated in the light-receiving layer 14 from the light-receiving layer 14 to the first electrode 11, and blocking electrons generated in the light-receiving layer 14 from moving toward the first electrode 11. Depending on the application, it may also have the role of blocking electron injection from the first electrode 11.

[0120] The hole transport layer 13 may be a single-layer structure made of one or more materials, or a laminated structure made of multiple layers of the same or different compositions. The hole transport material that can be contained in the hole transport layer 13 may be a known hole transport material. Examples of known hole transport materials include aromatic tertiary amine compounds, naphthalene compounds, anthracene compounds, tetracene compounds, pentacene compounds, phenanthrene compounds, pyrene compounds, perylene compounds, fluorene compounds, carbazole compounds, indole compounds, pyrrole compounds, picene compounds, thiophene compounds, benzotrifuran compounds, benzotrithiophene compounds, naphthodithiophene compounds, naphthothienothiophene compounds, benzodithiophene compounds, benzothiophene compounds, naphthobisbenzothiophene compounds, crisenodithiophene compounds, benzothienobenzothiophene compounds, indolocarbazole compounds, and the like. Among these, fluorene compounds, carbazole compounds, naphthodithiophene compounds, naphthothienothiophene compounds, benzodifuran compounds, benzothiophene compounds, naphthobisbenzothiophene compounds, crisenodithiophene compounds, benzothienobenzothiophene compounds, and indolocarbazole compounds are preferred, with fluorene compounds, carbazole compounds, crisenodithiophene compounds, benzothienobenzothiophene compounds, and indolocarbazole compounds being particularly preferred.

[0121] [Light receiving layer 14] A light-receiving layer 14 is provided between the hole transport layer 13 and the electron transport layer 15, which will be described later. Examples of materials for the light-receiving layer 14 include materials that have photoelectric conversion capabilities.

[0122] The light-receiving layer 14 may be a single-layer structure made of one or more materials, or it may be a laminated structure made of multiple layers of the same or different compositions. In particular, to improve photoelectric conversion efficiency, it is preferable that the light-receiving layer consists of layers containing at least two types of materials (organic components).

[0123] Examples of materials used in the light-receiving layer 14, which is a single-layer structure made of one type of material, include (i) coumarin and its derivatives, quinacridone and its derivatives, phthalocyanine and its derivatives, and so on. Examples of materials used in the light-receiving layer 14, which is a single-layer structure composed of two materials, include (i) coumarin and its derivatives, quinacridone and its derivatives, phthalocyanine and its derivatives, and (ii) fullerene and its derivatives, and other acceptor materials. The light-receiving layer 4 made of these materials may be formed by pre-mixing the powders and then depositing them, or by co-depositing them in any proportion. The materials used for the light-receiving layer 14, which is a single-layer structure composed of three materials, include (i) coumarin and its derivatives, quinacridone and its derivatives, phthalocyanine and its derivatives, (ii) fullerene and its derivatives, other acceptor materials, and (iii) hole transport materials. The light-receiving layer 14 made of these materials may be formed by pre-mixing the powders and then depositing them, or by co-depositing them in any proportion.

[0124] (i) Specific examples of coumarin derivatives include coumarin 6 and coumarin 30. Specific examples of quinacridone derivatives include N,N-dimethylquinacridone. Specific examples of phthalocyanine derivatives include boron subphthalocyanine chloride and boron subnaphthalocyanine chloride (SubNC). (ii) Specific examples of fullerenes and their derivatives include

[60] fullerene,

[70] fullerene, and [6,6]-phenyl-C61-methyl butyrate (

[60] PCBM). (iii) Preferred compounds and specific examples of hole transport materials include the same ones used in the hole transport layer 13 described above.

[0125] Furthermore, the material having photoelectric conversion functionality is not limited to being contained only in the light-receiving layer. For example, the material having photoelectric conversion functionality may also be contained in a layer adjacent to the light-receiving layer 14 (the hole transport layer 13 or the electron transport layer 15).

[0126] [Electron transport layer 15] An electron transport layer 15 is provided between the light-receiving layer 14 and the second electrode 16, which will be described later. The electron transport layer 15 has the role of transporting electrons generated in the photodetector layer 14 to the second electrode 16, and blocking the movement of holes from the second electrode 16 to the photodetector layer 14. Depending on the application, it may also have the role of blocking hole injection from the second electrode 16. The electron transport layer 15 may be divided into two or more layers using different materials.

[0127] The electron transport layer 15 contains the compound shown in formula (1) above. The electron transport layer 15 may also contain electron transport materials or metals other than the compound shown in formula (1), for example, fullerene, fullerene derivatives, triazine derivatives, bis(8-hydroxyquinolinate)manganese, tris(8-hydroxyquinolinate)aluminum, tris(2-methyl-8-hydroxyquinolinate)aluminum, BCP(2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline), Bphen(4,7-diphenyl-1,10-phenanthroline), BAlq(bis(2-methyl-8-quinolinate) Examples include (t)-4-(phenylphenolate)aluminum), 4,6-bis(3,5-di(pyridin-4-yl)phenyl)-2-methylpyrimidine, N,N'-diphenyl-1,4,5,8-naphthalenetetracarboxylic acid diimide, and N,N'-di(4-pyridyl)-1,4,5,8-naphthalenetetracarboxylic acid diimide, fullerene, fullerene derivatives, Liq(8-hydroxyquinolinolatolithium), Li, Na, K, Rb, Cs, Be, Mg, Ca, Sc, Ba, Ag, Eu, Yb, lithium fluoride, cesium carbonate, etc.

[0128] The electron transport layer 15 may be a single-layer structure made of one or more materials, or it may be a laminated structure made of multiple layers of the same or different compositions.

[0129] [Second electrode 16] A second electrode 16 is provided on the electron transport layer 15. Examples of materials for the second electrode 16 include indium-tin oxide (ITO), indium-zinc oxide (IZO), sodium, sodium-potassium alloy, magnesium, lithium, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al2O3) mixture, indium, lithium / aluminum mixture, gold, platinum, rare earth metals, molybdenum oxide, etc. The first electrode 11 and the second electrode 16 may be the same or different.

[0130] [Method of forming each layer] Each layer, excluding the first electrode 11 and the second electrode 16 described above, can be formed by thinning the material of each layer (along with binder resin and other materials and solvents as needed) using known methods such as vacuum deposition, spin coating, casting, or the LB (Langmuir-Blodgett method). There are no particular restrictions on the thickness of each layer formed in this way, and it can be selected as appropriate depending on the situation, but it is usually in the range of 5 nm to 5 μm.

[0131] The first electrode 11 and the second electrode 16 can be formed by thinning the electrode material using methods such as vapor deposition or sputtering. A pattern may be formed via a mask of a desired shape during vapor deposition or sputtering, or a pattern of a desired shape may be formed by photolithography after the thin film has been formed by vapor deposition or sputtering.

[0132] The film thickness of the first electrode 11 and the second electrode 16 is preferably 1 μm or less, and more preferably 10 nm to 200 nm.

[0133] The first electrode 11 and the second electrode 16 may be made of different materials as needed (this is also called an inverse structure). In such a structure, the photoelectric conversion element is configured such that light passes through the second electrode 16 and is incident on the light-receiving layer 14.

[0134] The image sensor equipped with the photoelectric conversion element of this embodiment can be applied, for example, to the image sensors of digital cameras and digital video cameras, and to the image sensors built into mobile phones, etc. The light sensor can be applied, for example, to television remote controls, air conditioner switches, automatic door opening and closing, etc.

[0135] <<Second Embodiment>> A photoelectric conversion element according to a second embodiment of the present invention is a solar cell having the stacked structure shown in Figure 1. The solar cell 1 has a hole transport promoting layer 12 and a hole transport layer 13 between the first electrode 11 and the light-receiving layer 14, and an electron transport layer 15 between the second electrode 16 and the light-receiving layer 14. However, some of these layers may be omitted, or other layers may be added.

[0136] [First electrode 11] The first electrode 11 is made of, for example, a transparent material, and the transparent material can be the transparent material described in the first embodiment. The first electrode 11 may be formed on any substrate (for example, a transparent substrate such as glass, plastic, or polymer film).

[0137] [Hole transport promotion layer 12] The material of the hole transport promoting layer 12 is the same as the material of the hole transport promoting layer 12 in the first embodiment (the compound shown in formula (1)). The material of the hole transport promoting layer 12 may also contain conventionally known hole transport materials in addition to the material in the first embodiment.

[0138] [Hole transport layer 13] The material of the hole transport layer 13 is the same as the material of the hole transport layer 13 in the first embodiment. In addition to the hole transport material in the first embodiment, the material of the hole transport layer 13 may also contain conventionally known hole transport materials.

[0139] [Light receiving layer 14] The material of the light-receiving layer 14 can be any material that uses an electron-donating material and an electron-accepting material, and may be a planar-coupled type in which the electron-donating material and the electron-accepting material are bonded to each other in a plane, or a bulk hetero-coupled type in which the electron-donating material and the electron-accepting material are mixed and formed into a film. The electron-donating material is not particularly limited, but organic semiconductors are preferred. Examples of electron-donating materials include polymer compounds such as polythiophene derivatives, polyfluorene derivatives, and polyphenylene vinylene derivatives and their copolymers, or low molecular weight compounds such as phthalocyanine derivatives and their metal complexes, porphyrin derivatives and their metal complexes, acene derivatives such as pentacene, and diamine derivatives. Inorganic semiconductors can also be used as electron-donating materials along with organic semiconductors, as long as the effects of the present invention are not impaired. The electron-accepting material is not particularly limited, but organic semiconductors are preferred. Examples of electron-accepting materials include fullerene derivatives, perylene derivatives, naphthalene derivatives, and the like.

[0140] [Electron transport layer 15] The electron transport layer 15 can be made of the electron transport material described in the first embodiment. Alternatively, alkali metal halides such as sodium fluoride and cesium fluoride, alkaline earth metal halogen compounds such as calcium fluoride, carbonates such as cesium carbonate, and inorganic n-type semiconductors such as titanium dioxide and zinc oxide may be used as the electron transport material.

[0141] [Second electrode 16] The second electrode 16 may be, but is not limited to, metals such as magnesium, calcium, sodium, potassium, titanium, indium, yttrium, lithium, gadolinium, aluminum, silver, tin, or lead, or alloys thereof.

[0142] The first electrode 11 and the second electrode 16 may be made of different materials as needed (this is also called an inverse structure). In such a structure, the photoelectric conversion element is configured such that light passes through the second electrode 16 and is incident on the light-receiving layer 14.

[0143] [Method of forming each layer] The method for forming each layer is not particularly limited. For example, the first electrode 11, hole transport enhancement layer 12, hole transport layer 13, light-receiving layer 14, electron transport layer 15, and second electrode 16 may be sequentially laminated on a substrate using methods such as vapor deposition, spin coating, casting, or pattern transfer. Alternatively, the hole transport enhancement layer 12, hole transport layer 13, light-receiving layer 14, and electron transport layer 15 may be laminated first, and then the first electrode 11 and second electrode 16 may be formed on this laminate by transfer, vapor deposition, sputtering, etc.

[0144] Organic electronic elements (photoelectric conversion elements, organic EL elements, etc.) and methods for forming each layer of said elements are not limited to the elements and methods shown in the embodiments described above. For example, the materials of the first electrode, the light-receiving layer (or light-emitting layer), the electron transport layer, and the second electrode can be appropriately replaced with other known materials. Furthermore, the hole injection layer and the hole transport layer can be replaced with layers formed by mixing a compound represented by formula (Q) with a hole transport material. [Examples]

[0145] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0146] (Synthesis Example 1: Synthesis of Compound (C-2)) Under an argon stream, 2.70 g (10.1 mmol) of naphthalene-1,4,5,8-tetracarboxylic dianhydride, 2.80 g (30.2 mmol) of acetamidoacetonitrile hydrochloride, and 1.11 g (8.56 mmol) of isoquinoline were suspended in 101 mL of DMF and stirred at 120 °C for 5 hours. After cooling to room temperature, an excess amount of toluene and ethanol was added for crystallization, and the precipitate (crude product) was collected by filtration. The obtained crude product was purified by recrystallization with DMF to obtain the target compound (C-2) (2.60 g, yield 75%). The obtained compound (C-2) was identified by 1 1H-NMR. 1 1H-NMR (DMSO-d6) δ (ppm): 5.11 (s, 4H), 8.76 (s, 4H).

[0147]

Chemical formula

[0148] (Synthesis Example 2: Synthesis of compound (C-72)) Under an argon stream, 2.00 g (7.46 mmol) of naphthalene-1,4,5,8-tetracarboxylic dianhydride, 1.07 g (15.3 mmol) of 2-cyanoethylamine, and 0.82 g (6.34 mmol) of isoquinoline were suspended in 30 mL of m-cresol and stirred at 120 °C for 6 hours. After cooling to room temperature, the precipitate (crude product) was collected by filtration. The obtained crude product was purified by recrystallization with DMF to obtain the target compound (C-72) (2.30 g, yield 83%). The obtained compound (C-72) was identified by 1 1H-NMR. 1 1H-NMR (DMSO-d6) δ (ppm): 2.97 (t, J = 6.6 Hz, 4H), 4.35 (t, J = 6.6 Hz, 4H), 8.74 (s, 4H).

[0149]

Chemical formula

[0150] (Synthesis Example 3: Synthesis of Compound (C-42)) Under an argon stream, 0.93 g (3.47 mmol) of naphthalene-1,4,5,8-tetracarboxylic dianhydride and 1.40 g (8.30 mmol) of 2-amino-2-phenylacetonitrile hydrochloride were suspended in 35 mL of pyridine and stirred at 120°C for 7 hours. After cooling to room temperature, 70 mL of ethanol was added to the reaction mixture, and the precipitate (crude product) was filtered off. The obtained crude product was purified by recrystallization with DMF to obtain the target compound (C-42) (1.00 g, yield 58%). 1 H-NMR(DMSO-d6)δ(ppm):7.37-7.46(m,6H),7.57-7.61(m,6H),8.74(s,4H).

[0151] [ka]

[0152] (Synthesis Example 4: Synthesis of Compound (C-262)) [ka] Under an argon atmosphere, 430 mg (1.01 mmol) of 2,6-dibromonaphthalene-1,4,5,8-tetracarboxylic dianhydride and 311 mg (4.44 mmol) of 2-cyanoethylamine were suspended in 20 mL of acetic acid and stirred at 110°C for 7.5 hours. After cooling to room temperature, the precipitate (crude product) was filtered off. The obtained crude product was purified with ethanol and hexane to obtain the target compound (C-262) (500 mg, yield 93%). 1 H-NMR(DMSO-d6)δ(ppm):8.78(s,2H),4.33(t,J=6.7Hz,4H),2.95(t,J=6.7Hz,4H).

[0153] (Synthesis Example 5: Synthesis of Compound (C-260)) [ka] Under an argon stream, 200 mg (0.38 mmol) of compound (C-262), 138 mg (1.13 mmol) of phenylboronic acid, and 8.71 mg (0.0075 mmol) of tetrakistriphenylphosphine palladium were suspended in 7.6 mL of dioxane and stirred at 100 °C for 7 hours. After cooling to room temperature, the precipitate (crude product) was collected by filtration. The obtained crude product was purified with water, ethanol, and hexane to obtain the target compound (C-260) (190 mg, yield 96%). 1 1H-NMR (DMSO-d6) δ (ppm): 8.41 (s, 2H), 7.48 - 7.55 (m, 10H), 4.23 (t, J = 6.7 Hz, 4H), 2.87 (t, J = 6.7 Hz, 4H).

[0154] (Synthesis Comparative Example 2: Synthesis of Compound (R-1)) The following compound (R-1) was synthesized by the method described in Journal of the American Chemical Society (2011), 133(39), 15256 - 15259. 1 1H-NMR (DMSO-d6) δ (ppm): 8.72 (s, 4H), 8.75 (s, 4H), 7.59 - 7.45 (m, 10H).

[0155] [Compound Used for Evaluation]

[0156] [Compound Used for Evaluation] [Chemical Formula] [Chemical Formula] [Chemical Formula] [Chemical Formula]

[0157] [Chemistry] [Chemistry]

[0158] [Fabrication and Evaluation of Photoelectric Conversion Element] [Element Example 1] A photoelectric conversion element 1 having a laminated structure composed of a substrate / second electrode 16 / electron transport layer 15 / light receiving layer 14 / hole transport layer 13 / hole transport promoting layer 12 / first electrode 11 was fabricated, and the dark current and external quantum efficiency of the photoelectric conversion element were evaluated.

[0159] (Preparation of Substrate and Second Electrode) As a substrate provided with a second electrode on its surface, a glass substrate with an ITO transparent electrode patterned in a stripe shape with an indium tin oxide (ITO) film (film thickness: 110 nm) having a width of 2 mm was prepared. Then, after washing this substrate with isopropyl alcohol, surface treatment was performed by ozone ultraviolet cleaning. (Preparation for Vacuum Deposition) On the substrate subjected to surface treatment after washing, vacuum deposition of each layer was performed by the vacuum deposition method to form each layer by lamination. First, the above glass substrate was introduced into the vacuum deposition chamber and evacuated to 7.0×10 -5 Pa. Then, each layer was fabricated according to the film formation conditions in the following order. (Fabrication of Electron Transport Layer 15) Compound (C-2) was formed into a film with a thickness of 10 nm at a rate of 0.03 nm / second to fabricate the electron transport layer 15. (Fabrication of Light Receiving Layer 14) 2Ph-BTBT, F6-SubPc-OC6F5, and fullerene (C60) were co-evaporated with a deposition rate ratio of 4:4:2 to form a film with a thickness of 200 nm. The film formation rate was 0.15 nm / second. (Fabrication of Hole Transport Layer 13) As a hole transport material, (HTL-1) was formed into a film with a thickness of 10 nm at a rate of 0.10 nm / second to fabricate the hole transport layer 13. (Fabrication of Hole Transport Promoting Layer 12) Compound (C-2) was deposited at a rate of 0.20 nm / second to create a 10 nm thick hole transport-promoting layer 12. (Fabrication of the first electrode 11) Finally, a metal mask was positioned perpendicular to the ITO stripes on the substrate, and the first electrode 11 was deposited. 80 nm of Au was deposited on the first electrode. The deposition rate of Au was 0.1 nm / second.

[0160] Therefore, the area is 4 mm². 2 A photoelectric conversion element 1, as shown in Figure 1, was fabricated. When a voltage of 2.5V (absolute value) was applied to the photoelectric conversion element fabricated as described above, such that electrons were transported to the second electrode 16 side and holes to the first electrode 11 side, the dark current (dark current, mA / cm²) was measured. 2 The dark current and external quantum efficiency were evaluated. Dark current was measured using a Keithley Source Measure Unit 2636B. A solar cell spectroscopic sensitivity analyzer (manufactured by Soma Optical Co., Ltd.) was used to measure the external quantum efficiency. The wavelength of the irradiated light was 560 nm, and the intensity was 50 μW / cm². 2 The measurement was performed using [this method]. The response time was measured at a wavelength of 560 nm and an intensity of 1.6 μW / cm². 2 The light was irradiated, and after stopping the irradiation, the time it took for the current value to return to the level before irradiation was measured.

[0161] The results are shown in Table 1. Note that the dark current, external quantum efficiency, and response time are relative values, with the results from Comparative Example 1 (described later) set as the baseline (100). A lower dark current value indicates better performance, and a higher external quantum efficiency value indicates better performance.

[0162] [Element Comparison Example 1] The photoelectric conversion element of Comparative Example 1 was fabricated using the same method as in Example 1, except that compound (R-1) was used instead of compound (C-42) in the fabrication of the electron transport layer 15. The dark current and external quantum efficiency were measured using the same method as in Example 1. The results are shown in Table 1.

[0163] [Table 1]

[0164] As shown in Table 1, the device examples using the material for photoelectric conversion elements for image sensors of the present invention showed suppressed dark current and high external quantum efficiency compared to the device examples. Similar effects were also confirmed for compounds (C-2) and (C-72).

[0165] <Evaluation of electron transport layer film quality> [Example A-1] A Si substrate (with native oxide film) is introduced into the vacuum deposition chamber, and 1.0 × 10 -4 The pressure was reduced to Pa. Then, a 30 nm film of the sublimation-purified compound (C-42) was deposited on the substrate, and the surface condition of the film was observed using an atomic force microscope (Shimadzu SPM-9600). The arithmetic mean roughness (Ra) measured in the surface roughness test was 0.24 nm.

[0166] [Example A-2] The measurement was performed in the same manner as in Example A-1, except that compound (C-2) was used instead of compound (C-42). The arithmetic mean roughness (Ra) in the surface roughness measurement was 6.67 nm.

[0167] [Comparative example B-1] The measurement was performed in the same manner as in Example A-1, except that compound (R-1) was used instead of compound (C-42). The arithmetic mean roughness (Ra) in the surface roughness measurement was 12.05 nm.

[0168] As shown above, when the film quality was evaluated, it was found that using the compound in the example allowed the surface roughness (Ra) to be kept below 10 nm, resulting in better film quality compared to the compound in the comparative example.

[0169] The photoelectric conversion element of the present invention, by containing the compound shown in formula (1) above, can improve electron transport capability and, when used in a photoelectric conversion element, can perform photoelectric conversion more efficiently. Furthermore, by containing the compound shown in formula (1) above, the dark current of the photoelectric conversion element of the present invention is suppressed, and it is expected that noise will be reduced when used in a photoelectric conversion element such as an image sensor. Moreover, by containing the compound shown in formula (1) above, the photoelectric conversion element of the present invention can have high external quantum efficiency and can convert light into electric current without loss, so high sensitivity can be expected as a photoelectric conversion element. [Explanation of Symbols]

[0170] 1. Photoelectric conversion element 11. First electrode 12. Hole transport-promoting layer 13. Hole transport layer 14. Light-receiving layer 15. Electron transport layer 16. Second electrode

Claims

1. It includes a first electrode, a second electrode, and a light-receiving layer and an organic layer disposed between the first electrode and the second electrode. The aforementioned organic layer includes an electron transport layer, The electron transport layer is a photoelectric conversion element containing a compound represented by the following formula (1). 【Chemistry 1】 (In formula (1), R ２ and R ３ Each of these independently represents an aliphatic hydrocarbon group having 1 to 15 carbon atoms. The aliphatic hydrocarbon group may be substituted with one or more groups selected from hydroxyl groups, carboxyl groups, formyl groups, nitro groups, fluoro groups, chloro groups, bromo groups, iodo groups, trifluoromethyl groups, cyano groups, carbon-oxygen double bonds, carbon-sulfur double bonds, aromatic hydrocarbon groups having 6 to 20 carbon atoms, heteroaromatic groups having 3 to 20 carbon atoms, and aliphatic hydrocarbon groups having 1 to 15 carbon atoms. The aliphatic hydrocarbon group may be linear, branched, or cyclic, and m and n each independently represent 1, 2, or 3. Ring A represents an aromatic hydrocarbon ring with 6 to 20 carbon atoms, or a heteroaromatic ring with 4 to 20 carbon atoms. The aromatic hydrocarbon ring and the heteroaromatic ring may each be a monoring, a fused ring, or a linked ring, and the linked ring may be bonded by methylene groups substituted with trifluoromethyl groups. The aromatic hydrocarbon ring and the heteroaromatic ring may be substituted with one or more groups selected from a hydroxyl group, a carboxyl group, a formyl group, a nitro group, a cyano group, a fluoro group, a chloro group, a bromo group, an iodo group, a fluoroalkyl group having 1 to 10 carbon atoms, a fluoroalkoxy group having 1 to 10 carbon atoms, an alkyl group having 1 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 20 carbon atoms, and a heteroaromatic group having 3 to 20 carbon atoms. The aromatic hydrocarbon ring and the heteroaromatic ring may be bonded to the aromatic hydrocarbon group or the heteroaromatic group by one or more selected from an oxygen atom, a carbonyl group, and a thiocarbonyl group. The aromatic hydrocarbon group and the heteroaromatic group may each be a monocyclic, fused, or linked ring.

2. The photoelectric conversion element according to claim 1, wherein the photoelectric conversion element is for use as an image sensor.

3. The photoelectric conversion element according to claim 1, wherein the light-receiving layer is a layer containing at least two organic components.

4. The photoelectric conversion element according to any one of claims 1 to 3, wherein the ring A in formula (1) is any of the following (A-1) to (A-17), which may be substituted with one or more of the groups. 【Chemistry 2】

5. The photoelectric conversion element according to claim 4, wherein ring A in formula (1) is either (A-1) or (A-2), which may be substituted with one or more of the groups.

6. R in formula (1) ２ and R ３ However, each is independently a methylene group or an ethylene group, The photoelectric conversion element according to any one of claims 1 to 3, wherein the methylene group and the ethylene group may be substituted with one or more groups selected from a hydroxyl group, a carboxyl group, a formyl group, a nitro group, a fluoro group, a chloro group, a bromo group, an iodo group, a trifluoromethyl group, a cyano group, a carbon-oxygen double bond, a carbon-sulfur double bond, an aromatic hydrocarbon group having 6 to 20 carbon atoms, a heteroaromatic group having 3 to 20 carbon atoms, and an aliphatic hydrocarbon group having 1 to 15 carbon atoms.

7. R in formula (1) ２ and R ３ However, each is independently a methylene group or an ethylene group, The photoelectric conversion element according to any one of claims 1 to 3, wherein the methylene group and the ethylene group may be substituted with one or more groups selected from cyano, fluoro, methyl, cyclohexyl, adamantyl, trifluoromethyl, phenyl, pyridyl, pyrimidyl, pyrazyl, triazyl, quinolyl, isoquinolyl, naphthyl, phenanthryl, and anthryl groups.

8. R in formula (1) ２ and R ３ However, each is independently a methylene group or an ethylene group, A photoelectric conversion element according to any one of claims 1 to 3, which is substituted with one or more groups selected from cyano, fluoro, methyl, cyclohexyl, adamantyl, trifluoromethyl, phenyl, pyridyl, pyrimidyl, pyrazyl, triazyl, quinolyl, isoquinolyl, naphthyl, phenanthryl, and anthryl groups.

9. An electron transport material containing a compound represented by the following formula (2). 【Transformation 3】 (In formula (2), R ４ and R ５ each independently represents an aliphatic hydrocarbon group having 1 to 15 carbon atoms, The aliphatic hydrocarbon group may be substituted with one or more groups selected from hydroxyl groups, carboxyl groups, formyl groups, nitro groups, fluoro groups, chloro groups, bromo groups, iodo groups, trifluoromethyl groups, cyano groups, carbon-oxygen double bonds, carbon-sulfur double bonds, aromatic hydrocarbon groups having 6 to 20 carbon atoms, heteroaromatic groups having 3 to 20 carbon atoms, and aliphatic hydrocarbon groups having 1 to 15 carbon atoms. The aliphatic hydrocarbon group may be linear, branched, or cyclic, and m and n each independently represent 1, 2, or 3. Ring B represents an aromatic hydrocarbon ring with 6 to 20 carbon atoms, or a heteroaromatic ring with 4 to 20 carbon atoms. The aromatic hydrocarbon ring and the heteroaromatic ring may each be a monoring, a fused ring, or a linked ring, and the linked ring may be bonded by methylene groups substituted with trifluoromethyl groups. The aromatic hydrocarbon ring and the heteroaromatic ring may be substituted with one or more groups selected from a hydroxyl group, a carboxyl group, a formyl group, a nitro group, a cyano group, a fluoro group, a chloro group, a bromo group, an iodo group, a fluoroalkyl group having 1 to 10 carbon atoms, a fluoroalkoxy group having 1 to 10 carbon atoms, an alkyl group having 1 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 20 carbon atoms, and a heteroaromatic group having 3 to 20 carbon atoms. The aromatic hydrocarbon ring and the heteroaromatic ring may be bonded to the aromatic hydrocarbon group or the heteroaromatic group by one or more selected from an oxygen atom, a carbonyl group, and a thiocarbonyl group. The aromatic hydrocarbon group and the heteroaromatic group may each be a monocyclic, fused, or linked ring.

10. The electron transport material according to claim 9, which is a material for a photoelectric conversion element.

11. The electron transport material according to claim 9, which is a material for an imaging photoelectric conversion element.

12. The electron transport material according to any one of claims 9 to 11, wherein the ring B in formula (2) is any of the following (B-1) to (B-17), which may be substituted with one or more of the groups. 【Chemistry 4】

13. The electron transport material according to claim 12, wherein the ring B in formula (2) is either (B-1) or (B-2), which may be substituted with one or more of the groups.

14. R in formula (2) ４ and R ５ However, each is independently a methylene group or an ethylene group, The electron transport material according to any one of claims 9 to 11, wherein the methylene group and the ethylene group may be substituted with one or more groups selected from a hydroxyl group, a carboxyl group, a formyl group, a nitro group, a fluoro group, a chloro group, a bromo group, an iodo group, a trifluoromethyl group, a cyano group, a carbon-oxygen double bond, a carbon-sulfur double bond, an aromatic hydrocarbon group having 6 to 20 carbon atoms, a heteroaromatic group having 3 to 20 carbon atoms, and an aliphatic hydrocarbon group having 1 to 15 carbon atoms.

15. R in formula (2) ４ and R ５ However, each is independently a methylene group or an ethylene group, The electron transport material according to any one of claims 9 to 11, wherein the methylene group and the ethylene group may be substituted with one or more groups selected from cyano, fluoro, methyl, cyclohexyl, adamantyl, trifluoromethyl, phenyl, pyridyl, pyrimidyl, pyrazyl, triazyl, quinolyl, isoquinolyl, naphthyl, phenanthryl, and anthryl groups.

16. R in formula (2) ４ and R ５ However, each is independently a methylene group or an ethylene group, An electron transport material according to any one of claims 9 to 11, which is substituted with one or more groups selected from a cyano group, a fluoro group, a methyl group, a cyclohexyl group, an adamantyl group, a trifluoromethyl group, a phenyl group, a pyridyl group, a pyrimidyl group, a pyrazyl group, a triazyl group, a quinolyl group, an isoquinolyl group, a naphthyl group, a phenanthryl group, and an anthyl group.

Images