Photoelectric conversion element for image sensor

Abstract

Provided is a photoelectric conversion element for an image pickup device that is excellent in dark current characteristics and responsiveness. 【Solution means】Between a first electrode and a second electrode, a photoelectric conversion element for an image pickup device including a photoelectric conversion layer and a hole transport layer, the photoelectric conversion layer contains at least two kinds of organic materials, and the hole transport layer contains a compound represented by the following formula (1). TIFF2026047344000035.tif28134 (In formula (1), Ar 1 ~Ar 4 are each independently an optionally substituted aromatic hydrocarbon group having 6 to 30 carbon atoms, a monocyclic ring, a linked ring, or a condensed ring of 4 or less rings, etc., and R 11 ~R 12 are each independently a nitro group, etc., L is a direct bond, etc., Ar 1 and Ar 2 , Ar 3 and L, Ar 4 and L may be bonded to each other to form a ring, and m and n represent integers from 0 to 3.)

Description

[Technical Field]

[0001] This invention relates to a photoelectric conversion element for an image sensor. [Background technology]

[0002] Materials for photoelectric conversion elements used in image sensors are used in applications such as mobile phones and cameras, and their development is being actively pursued.

[0003] In recent years, market demand for materials used in photoelectric conversion elements for image sensors has been increasing, with a need for materials that excel in dark current, external quantum efficiency, and response speed. Under these circumstances, the potential of various polycyclic compounds is being explored and investigated. As an example of a polycyclic compound, Patent Document 1 discloses the use of a derivative with dibenzo[g,p]chrysene as the parent material as a hole transport material for a photoelectric conversion element in an image sensor. Furthermore, Patent Document 2 discloses the use of a derivative with indenophenanthrene as the parent material as a buffer layer or photoelectric conversion layer material for a photoelectric conversion element in an image sensor. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] International Publication No. 2022 / 260096 [Patent Document 2] International Publication No. 2022 / 071444 [Overview of the project] [Problems that the invention aims to solve]

[0005] However, the compounds disclosed in Patent Documents 1 and 2 do not exhibit sufficient dark current characteristics and responsiveness, and there is a need for photoelectric conversion element materials with even better properties in these areas.

[0006] The object of the present invention is to provide a photoelectric conversion element for an image sensor that has excellent dark current characteristics and responsiveness. [Means for solving the problem]

[0007] The inventors of the present invention have discovered that the above problems can be solved by using a specific compound in the hole transport layer of a photoelectric element for an image sensor having a photoelectric conversion layer and a hole transport layer, and have completed the present invention.

[0008] Aspects of this disclosure relate to photoelectric conversion elements for the following image sensors.

[0009] [1] A photoelectric element for an image sensor, comprising a photoelectric conversion layer and a hole transport layer between a first electrode and a second electrode, The photoelectric conversion layer comprises at least two types of organic materials, The hole transport layer contains a compound represented by the following formula (1): A photoelectric conversion element for image sensors. [ka] (In formula (1), Ar 1 ~Ar 4 Each of these is independently an aromatic hydrocarbon group having 6 to 30 carbon atoms, which may be substituted, a monocyclic, linked, or fused ring of 4 or fewer rings; a heteroaryl group having 3 to 30 carbon atoms, which may be substituted, which contains only one heteroatom; or a group combining these. R 11 ~R 12 Each of these is independently a nitro group, a halogen atom, an alkyl halide, an acyl group, a sulfonyl group, a phosphoryl group, an amino group, an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 1 to 20 carbon atoms, a cycloalkyl group having 1 to 20 carbon atoms, a bicycloalkyl group having 1 to 20 carbon atoms, a tricycloalkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 30 carbon atoms, a heteroaryl group having 3 to 30 carbon atoms, or a group that is a combination of these. L is a monocyclic, fused ring, or polycyclic aromatic hydrocarbon group having 6 to 30 carbon atoms which may be directly bonded or substituted, a heteroaryl group having 3 to 30 carbon atoms which may be monocyclic, fused ring, or polycyclic and having 4 or fewer rings, or a group combining them, Ar 1 and Ar 2 Ar 3 and L, Ar 4 and L may be bonded to each other to form a ring, Ar 1 ~Ar 4 When any of the aromatic hydrocarbon group, the heteroaryl group, the aromatic hydrocarbon group represented by L, and the heteroaryl group represented by the above is substituted with a substituent, the substituent is independently a nitro group, a halogen atom, a halogenated alkyl group, an acyl group, a sulfonyl group, a phosphoryl group, an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 1 to 20 carbon atoms, a cycloalkyl group having 1 to 20 carbon atoms, a bicycloalkyl group having 1 to 20 carbon atoms, a tricycloalkyl group having 1 to 20 carbon atoms, or an alkoxy group having 1 to 10 carbon atoms, m and n represent integers from 0 to 3.) [2] The photoelectric conversion element for an imaging device according to [1], wherein Ar 3 and Ar 4 are groups represented by the following formula (2).

Chemical formula

[10] A photoelectric element for an image sensor according to any one of [1] to [9], wherein the photoelectric conversion layer comprises at least three materials.

[11] Between the first electrode and the second electrode, a photoelectric conversion layer, a hole transport layer, and a buffer layer are provided in this order. The buffer layer contains an organic material. A photoelectric conversion element for an image sensor as described in any of [1] to

[10] .

[12] The photoelectric conversion layer comprises a fullerene, a photoelectric conversion element for an image sensor according to any one of [1] to

[11] . [Effects of the Invention]

[0010] According to one aspect of the present invention, a photoelectric conversion element for an image sensor that exhibits excellent dark current characteristics and responsiveness can be provided. [Brief explanation of the drawing]

[0011] [Figure 1] This is a schematic cross-sectional view showing an example of a stacked configuration of photoelectric conversion elements for an image sensor according to one aspect of the present invention. [Modes for carrying out the invention]

[0012] The following describes in detail a photoelectric conversion element for an image sensor according to one aspect of this disclosure.

[0013] Compounds used in hole transport layers of photoelectric conversion elements for image sensors. The compound represented by the following formula (1) can be suitably used as a compound for the hole transport layer in a photoelectric conversion element for an image sensor. In other words, a photoelectric conversion element for an image sensor according to one aspect of the present disclosure includes a compound represented by the following formula (1). [ka] (In formula (1), Ar 1 ~Ar 4 Each of these is independently an aromatic hydrocarbon group having 6 to 30 carbon atoms, which may be substituted, a monocyclic, linked, or fused ring of 4 or fewer rings; a heteroaryl group having 3 to 30 carbon atoms, which may be substituted, which contains only one heteroatom; or a group combining these. R 11 ~R 12Each of these is independently a nitro group, a halogen atom, an alkyl halide, an acyl group, a sulfonyl group, a phosphoryl group, an amino group, an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 1 to 20 carbon atoms, a cycloalkyl group having 1 to 20 carbon atoms, a bicycloalkyl group having 1 to 20 carbon atoms, a tricycloalkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 30 carbon atoms, a heteroaryl group having 3 to 30 carbon atoms, or a group that is a combination of these. L is a monocyclic, linked, or fused ring of 4 or fewer rings, aromatic hydrocarbon group having 6 to 30 carbon atoms, which may be directly bonded or substituted; a monocyclic, linked, or fused ring of 4 or fewer rings, heteroaryl group having 3 to 30 carbon atoms, which may be substituted; or a group combining these. Ar 1 and Ar 2 Ar 3 and L, Ar 4 And L may be bonded to each other to form a ring, Ar 1 ~Ar 4 If any of the aromatic hydrocarbon group represented by L, the heteroaryl group, the aromatic hydrocarbon group represented by L, or the heteroaryl group has a substituent, then each substituent is independently a nitro group, a halogen atom, an alkyl halide, an acyl group, a sulfonyl group, a phosphoryl group, an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 1 to 20 carbon atoms, a cycloalkyl group having 1 to 20 carbon atoms, a bicycloalkyl group having 1 to 20 carbon atoms, a tricycloalkyl group having 1 to 20 carbon atoms, or an alkoxy group having 1 to 10 carbon atoms. m and n represent integers between 0 and 3.

[0014] Having the above-described specific structure, a photoelectric conversion element for an image sensor containing the compound represented by formula (1) can provide a photoelectric conversion element with low dark current and excellent responsiveness. For this reason, the compound represented by formula (1) is suitably used as a hole transport layer for an image sensor.

[0015] The preferred embodiment of the definition in formula (1) above is as follows:

[0016] <Ar 1 ~Ar 4 > (Aromatic hydrocarbon group) Ar 1 ~Ar 4 As an aromatic hydrocarbon group having 6 to 30 carbon atoms, which may be substituted, and which is a monocyclic, linked, or fused ring of 4 or fewer rings, a preferred aromatic hydrocarbon group having 6 to 20 carbon atoms is a monocyclic, linked, or fused ring of 4 or fewer rings.

[0017] Examples of such aromatic hydrocarbon groups include phenyl, naphthyl, anthryl, phenanthryl, pyrenyl, chrysenyl, triphenylenyl, fluorenyl, benzofluorenyl, and combinations thereof. More specifically, Examples include phenyl group, biphenyl group, terphenyl group, naphthyl group, anthryl group, phenanthryl group, pyrenyl group, chrysenyl group, triphenylenyl group, fluorenyl group, benzofluorenyl group, naphthylphenyl group, phenylnaphthyl group, naphthylnaphthyl group, phenanthrylphenyl group, phenylphenanthryl group, triphenylenylphenyl group, and phenyltriphenylenyl group.

[0018] (heteroaryl group) Ar 1 ~Ar 4 Examples of heteroaryl groups that contain only one heteroatom, having 3 to 30 carbon atoms and which may be substituted, and which are monocyclic or fused rings of 4 or fewer rings, include heteroaryl groups having 3 to 30 carbon atoms and which contain one atom selected from the group consisting of oxygen, nitrogen, and sulfur atoms on the aromatic ring, and which are monocyclic or fused rings of 4 or fewer rings.

[0019] Examples of the heteroaryl group include dibenzofuranyl group, dibenzothionyl group, carbazolyl group, benzocarbazolyl group, pyrrolyl group, thienyl group, furanyl group, pyridyl group, indolyl group, benzothienyl group, benzofuranyl group, quinolyl group, isoquinolyl group, dibenzothienyl group, dibenzofuranyl group, and the like. Ar 1 ~Ar 4 Examples of groups formed by combining these groups include dibenzofuranylphenyl group, dibenzothionylphenyl group, carbazolylphenyl group, phenylpyridyl group, pyridylphenyl group, 9-phenylcarbazolyl group, 9-(biphenylyl)carbazolyl group, 9-(naphthyl)carbazolyl group, 9-(naphthylphenyl)carbazolyl group, 9-(phenanthryl)carbazolyl group, and 9-(triphenylenyl)carbazolyl group.

[0020] <R 11 ~R 12 >

[0021] R 11 ~R 12 Examples of halogen atoms represented by include fluorine atoms, chlorine atoms, and bromine atoms. Among these, fluorine atoms are preferred.

[0022] R 11 ~R 12 As the halogenated alkyl group represented by , for example, halogenated alkyl groups having 1 to 5 carbon atoms are preferred, and halogenated alkyl groups having 1 to 3 carbon atoms are more preferred. Furthermore, as the halogenated alkyl group, fluorinated alkyl groups are preferred, and perfluoroalkyl groups are more preferred. As the fluorinated alkyl group, perfluorobutyl group, perfluoropropyl group, perfluoroethyl group, and trifluoromethyl group are preferred, and the trifluoromethyl group is more preferred.

[0023] R 11 ~R 12The acyl group represented by is preferably an acyl group having 2 to 10 carbon atoms. Examples of such acyl groups include an acetyl group, a propionyl group, an acryloyl group, a methacryloyl group, a benzoyl group, and the like.

[0024] R 11 ~R 12 As the alkyl group having 1 to 20 carbon atoms represented by , for example, a linear or branched alkyl group having 1 to 20 carbon atoms is preferred. Examples of such alkyl groups include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, a pentyl group, an n-hexyl group, a cyclohexyl group, an octyl group, a decyl group, a dodecyl group, an octadecyl group, and the like.

[0025] R 11 ~R 12 As the alkenyl group having 1 to 20 carbon atoms represented by , an alkenyl group having 2 to 20 carbon atoms is preferred. Examples of such alkenyl groups include ethenyl group, propenyl group, butenyl group, 2-methylpropenyl group, n-pentenyl group, 2-methylbutenyl group, n-hexenyl group, 2-methylpentenyl group, n-heptenyl group, n-octenyl group, 2-ethylhexenyl group, n-nonel group, 2-ethylheptenyl group, n-decenyl group, n-dodecenyl group, cyclopentenyl-1- group, cyclohexenyl-1- group, and cycloheptenyl-1- group.

[0026] R 11 ~R 12 As the cycloalkyl group having 1 to 20 carbon atoms represented by , a cycloalkyl group having 3 to 20 carbon atoms is preferred. Examples of such cycloalkyl groups include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group.

[0027] R 11 ~R 12As the bicycloalkyl group having 1 to 20 carbon atoms represented by , bicycloalkyl groups having 6 to 20 carbon atoms are preferred. Examples of such bicycloalkyl groups include exo-2-norbornyl group, endo-2-norbornyl group, 3-pinanyl group, bicyclo[1,2,2]heptan-2-yl group, and bicyclo[2,2,2]octane-3-yl group.

[0028] R 11 ~R 12 As the tricycloalkyl group having 1 to 20 carbon atoms represented by , a tricycloalkyl group having 9 to 20 carbon atoms is preferred. Examples of such tricycloalkyl groups include a 1-adamantyl group and a 2-adamantyl group.

[0029] R 11 ~R 12 Examples of alkoxy groups with 1 to 10 carbon atoms represented by include methoxy group, ethoxy group, n-propyloxy group, isopropyloxy group, cyclopropyloxy group, n-butyloxy group, isobutyloxy group, sec-butyloxy group, tert-butyloxy group, cyclobutyloxy group, n-pentyloxy group, cyclopentyloxy group, n-hexyloxy group, cyclohexyloxy group, n-heptyloxy group, n-octyloxy group, n-nonyloxy group, n-decyloxy group, norbornyloxy group, and adamantyloxy group.

[0030] R 11 ~R 12 As an aromatic hydrocarbon group having 6 to 30 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms is preferred. As an aromatic hydrocarbon group, the aforementioned Ar 1 ~Ar 4 Examples similar to aromatic hydrocarbon groups in the above context include the following:

[0031] R 11 ~R 12Examples of heteroaryl groups having 3 to 30 carbon atoms, represented by , include monocyclic, linked, or fused rings of 4 or fewer carbon atoms, containing at least one atom selected from the group consisting of oxygen, nitrogen, and sulfur atoms on the aromatic ring. Examples of the heteroaryl group include dibenzofuranyl group, dibenzothionyl group, carbazolyl group, benzocarbazolyl group, pyrrolyl group, thienyl group, furanyl group, imidazolyl group, pyrazolyl group, thiazolyl group, isothiazolyl group, oxazolyl group, isoxazolyl group, pyridyl group, pyrimidyl group, pyrazyl group, indolyl group, benzothienyl group, benzofuranyl group, benzimidazolyl group, indazolyl group, benzothiazolyl group, benzoisothiazolyl group, 2,1,3-benzothiadiazolyl group, benzoxazolyl group, benzoisoxazolyl group, 2,1,3-benzoxadiazolyl group, quinolyl group, isoquinolyl group, quinoxalyl group, quinazolyl group, dibenzothienyl group, dibenzofuranyl group, phenoxazinyl group, phenothiazinyl group, phenazine group, thianthrenyl group, and the like.

[0032] <l> (Aromatic hydrocarbon group) As an aromatic hydrocarbon group having 6 to 30 carbon atoms, which may be substituted, and which is monocyclic, linked, or fused with 4 or fewer rings, represented by L, an aromatic hydrocarbon group having 6 to 18 carbon atoms, which is monocyclic, linked, or fused with 4 or fewer rings, is preferred. As an aromatic hydrocarbon group, the above-mentioned Ar 1 ~Ar 4 Examples similar to aromatic hydrocarbon groups in the above context include the following:

[0033] (heteroaryl group) Examples of heteroaryl groups having 3 to 30 carbon atoms, which may be substituted, include monocyclic, linked, or fused rings of 4 or fewer rings, represented by L, which contain at least one atom selected from the group consisting of oxygen, nitrogen, and sulfur atoms on the aromatic ring. 11 ~R 12 Examples similar to heteroaryl groups in this context include...

[0034] <Substituent> As mentioned above, Ar 1 ~Ar 4 The above aromatic hydrocarbon group represented by , the above heteroaryl group, the above aromatic hydrocarbon group represented by L, or the above heteroaryl group may have substituents. The substituents include halogen atoms, alkyl halides, acyl groups, alkyl groups having 1 to 20 carbon atoms, alkenyl groups having 1 to 20 carbon atoms, cycloalkyl groups having 1 to 20 carbon atoms, bicycloalkyl groups having 1 to 20 carbon atoms, tricycloalkyl groups having 1 to 20 carbon atoms, or alkoxy groups having 1 to 10 carbon atoms, as described above. 11 ~R 12 Examples include halogen atoms, alkyl halides, acyl groups, alkyl groups having 1 to 20 carbon atoms, alkenyl groups having 1 to 20 carbon atoms, cycloalkyl groups having 1 to 20 carbon atoms, bicycloalkyl groups having 1 to 20 carbon atoms, tricycloalkyl groups having 1 to 20 carbon atoms, or alkoxy groups having 1 to 10 carbon atoms.

[0035] <Preferred embodiments of the compound represented by formula (1)> The preferred embodiments of the compound represented by formula (1) will be described below.

[0036] In the compound represented by formula (1), the aforementioned Ar 3 and Ar 4 are preferably groups represented by the following formula (2). [Chemical formula] (In formula (2), R 1 ~R 2 and R 4 ~R 5 are each independently a hydrogen atom, a nitro group, a halogen atom, a halogenated alkyl group, an acyl group, a sulfonyl group, a phosphoryl group, an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 1 to 20 carbon atoms, a cycloalkyl group having 1 to 20 carbon atoms, a bicycloalkyl group having | 1 to 20 carbon atoms, a tricycloalkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 24 carbon atoms, which is a monocyclic, linked ring, or condensed ring of 4 or less rings, a heteroaryl group having 3 to 24 carbon atoms, which is a monocyclic or condensed ring of 4 or less rings and contains only one heteroatom, or a group combining them, R 3 is a nitro group, a halogen atom, a halogenated alkyl group, an acyl group, a sulfonyl group, a phosphoryl group, an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 1 to 20 carbon atoms, a cycloalkyl group having 1 to 20 carbon atoms, a bicycloalkyl group having | 1 to 20 carbon atoms, a tricycloalkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 24 carbon atoms, which is a monocyclic, linked ring, or condensed ring of 4 or less rings, a heteroaryl group having 3 to 24 carbon atoms, which is a monocyclic or condensed ring of 4 or less rings and contains only one heteroatom, or a group combining them, R 1 ~R 5 may be linked to each other to form a condensed ring of 4 or less rings for formula (2).)

[0037] R 1 ~R 2 、R 4 ~R 5 、およびR 3 The halogen atom, halogenated alkyl group, acyl group, alkyl group having 1 to 20 carbon atoms, alkenyl group having 1 to 20 carbon atoms, cycloalkyl group having 1 to 20 carbon atoms, bicycloalkyl group having 1 to 20 carbon atoms, tricycloalkyl group having 1 to 20 carbon atoms, and alkoxy group having 1 to 10 carbon atoms represented by are the aforementioned R 11 ~R 12 In ~R

[0038] R 1 ~R 2 、R 4 [[ID=2)7]]~R 5 、およびR 3 The aromatic hydrocarbon group having 6 to 24 carbon atoms, monocyclic, linked ring, or condensed ring of 4 rings or less, and the heteroaryl group having 3 to 24 carbon atoms, monocyclic, or condensed ring of 4 rings or less, containing only one heteroatom represented by are the aforementioned Ar 1 ~Ar 4 In ~Ar

[0039] In the compound represented by formula (1), the groups represented by the aforementioned Ar 3 およびAr 4 are preferably aromatic hydrocarbon groups having 6 to 24 carbon atoms, monocyclic, linked ring, or condensed ring of 4 rings or less, which may be substituted.

[0040] In the compound represented by formula (1), the aforementioned Ar 1 ~Ar 4 , R 11 ~R 12 In L, the aromatic hydrocarbon group is preferably a group formed from a 5-membered ring and / or a 6-membered ring.

[0041] In the compound represented by formula (1), the aforementioned Ar 1 ~Ar 4 , R 11 ~R 12 In L, the heteroaryl group is preferably a carbazolyl group or a group containing a carbazolyl group.

[0042] In the compound represented by formula (1), the aforementioned Ar 1 and Ar 2 It is preferably an aromatic hydrocarbon group having 6 to 12 carbon atoms, which may be substituted, and is monocyclic or fused with four or fewer rings. Ar 1 ~Ar 2 More preferred substituents include phenyl groups and naphthyl groups.

[0043] In the compound represented by formula (1), the aforementioned L is preferably a monocyclic or fused ring of 4 or fewer rings, aromatic hydrocarbon group, or carbazolediyl group, having 6 to 18 carbon atoms, which may be directly bonded or substituted.

[0044] In the compound represented by formula (1), it is preferable that m and n are 0.

[0045] In the compound represented by formula (1), it is preferable that formula (1) is represented by the following formula (3). [ka] (In the formula, Ar 3 ~Ar 4 , R 11 ~R 12 L, m, and n are the same as in equation (1). p represents either 0 or 1. When p is 0, it indicates that the phenyl groups on either side of (X)p are not directly bonded. If p is 1, X represents a direct connection.

[0046] <Physical properties of the compound represented by formula (1)> The preferred physical properties of the compound represented by formula (1) are described below.

[0047] (HOMO value) The HOMO value of the compound represented by formula (1) is not particularly limited, but is preferably 5.0 to 6.5 eV from the viewpoint of compatibility with photoelectric conversion elements for image sensors. It is even more preferably 5.3 to 6.0 eV. This HOMO value was obtained from measurements of the deposited film using an atmospheric photoelectron yield spectrometer.

[0048] (Band gap) The band gap of the compound represented by formula (1) is not particularly limited, but is preferably 2.5 to 4.0 eV from the viewpoint of compatibility with photoelectric conversion elements for image sensors. This band gap is a value obtained from the wavelength edge of the absorption spectrum of the deposited film.

[0049] (LUMO value) The LUMO value of the compound represented by formula (1) is not particularly limited, but is preferably 2.0 to 3.5 eV from the viewpoint of compatibility with photoelectric conversion elements for image sensors. This LUMO value is obtained from the above HOMO value and band gap.

[0050] (Glass transition temperature) The glass transition temperature of the compound represented by formula (1) is not particularly limited, but is preferably 140°C or higher from the viewpoint of compatibility with photoelectric conversion elements for image sensors. This glass transition temperature is a value obtained from differential scanning calorimetry.

[0051] (molecular weight) The molecular weight of the compound represented by formula (1) is not particularly limited, but from the viewpoint of achieving both a high glass transition temperature and heat stability during sublimation, it is preferably less than 1000, and more preferably between 680 and 1000.

[0052] <Specific examples of compounds represented by formula (1)> The following are examples of preferred compounds represented by formula (1), but the compounds are not limited to these. [ka]

[0053] [ka]

[0054] [ka]

[0055] [ka]

[0056] [ka]

[0057] [ka]

[0058] [ka]

[0059] [ka]

[0060]

change

[0061]

change

[0062]

change

[0063]

change

[0064]

change

[0065]

change

[0066]

change

[0067]

change

[0068]

change

[0069]

change

[0070]

change

[0071] [ka]

[0072] <Uses of the compound represented by formula (1)> The compound represented by formula (1) can be used as a material for photoelectric conversion elements. Examples of photoelectric conversion element materials that can be used with the compound represented by formula (1) include photoelectric conversion element materials for image sensors. Preferred photoelectric conversion element materials for image sensors that can be used with the compound represented by formula (1) include, for example, charge transport materials or charge blocking materials for image sensors. Preferred charge transport materials for image sensors that can be used with the compound represented by formula (1) include, for example, hole transport materials for image sensors. Preferred charge blocking materials for image sensors that can be used with the compound represented by formula (1) include, for example, electron blocking materials for image sensors.

[0073] The following describes, as an example, a photoelectric conversion element for an image sensor according to this embodiment.

[0074] <<Photoelectric conversion element for image sensors>> The photoelectric conversion element for the image sensor of this embodiment includes a photoelectric conversion layer and a hole transport layer between the first electrode and the second electrode. The above photoelectric conversion layer includes at least two types of organic materials. The hole transport layer described above contains the compound represented by formula (1) mentioned above.

[0075] The layer configuration of the photoelectric conversion element for the image sensor is not particularly limited, but examples include the configurations shown in (A) to (D) below. (A) A photoelectric conversion layer and a hole transport layer are provided between the first electrode and the second electrode in this order. (B) Between the first electrode and the second electrode, a photoelectric conversion layer, a hole transport layer, and a buffer layer are provided in this order. (C) Between the first electrode and the second electrode, an electron transport layer, a photoelectric conversion layer, and a hole transport layer are provided in this order. (D) Between the first electrode and the second electrode, an electron transport layer, a photoelectric conversion layer, a hole transport layer, and a buffer layer are provided in this order. Here, the photoelectric conversion element can receive light from either the first electrode or the second electrode.

[0076] The configuration of the photoelectric conversion element for the image sensor is not particularly limited, but for example, the following configurations (i) to (iii) can be cited.

[0077] (i) First electrode / photoelectric conversion layer / hole transport layer (electron blocking layer) / second electrode (ii) First electrode / electron transport layer (hole blocking layer) / photoelectric conversion layer / hole transport layer (electron blocking layer) / second electrode (iii) First electrode / electron transport layer (hole blocking layer) / photoelectric conversion layer / hole transport layer (electron blocking layer) / buffer layer / second electrode

[0078] The buffer layer may be replaced with another layer with a different name or function, if necessary. Examples of other layers with different names or functions include hole injection layers and work function adjustment layers.

[0079] The compound represented by formula (1) may be included in multiple layers other than the hole transport layer of the photoelectric conversion element for the image sensor.

[0080] The photoelectric conversion element for the image sensor according to this embodiment will be described in more detail below, with reference to Figure 1, using the configuration of (iii) above as an example. Figure 1 is a schematic cross-sectional view showing an example of a stacked configuration of the photoelectric conversion element for the image sensor according to this embodiment. Of the embodiments of each layer described below, the same embodiments as those for the layers described in (i) and (ii) above will apply.

[0081] The photoelectric conversion element 100 for the image sensor shown in Figure 1 comprises, in this order, a substrate 1, a first electrode 2, an electron transport layer (hole blocking layer) 3, a photoelectric conversion layer 4, a hole transport layer (electron blocking layer) 5, a buffer layer 6, and a second electrode 7. In this embodiment, some of these layers may be omitted, or other layers may be added.

[0082] In the photoelectric conversion element 100 for the image sensor, light is incident from below the transparent first electrode 2. Furthermore, a voltage is applied to the photoelectric conversion element 100 such that electrons move to the first electrode 2 and holes move to the second electrode 7 from the charge (holes and electrons) generated in the photoelectric conversion layer 4. In other words, the photoelectric conversion element 100 uses the first electrode 2 as an electron collection electrode and the second electrode 7 as a hole collection electrode.

[0083] The compound represented by formula (1) may be included in multiple layers other than the hole transport layer of the photoelectric conversion element 100 for the image sensor.

[0084] The following describes a photoelectric conversion element 100 for an image sensor in which the hole transport layer (electron blocking layer) 5 contains a compound represented by formula (1).

[0085] [Circuit board 1] There are no particular limitations on the substrate, and examples include glass plates, quartz plates, plastic plates, etc. In a configuration where light is incident from the substrate 1 side, it is preferable that the substrate 1 has high transmittance with respect to the wavelength of light (for example, transmittance of 80% or more, preferably transmittance of 90% or more).

[0086] [First electrode 2] A first electrode 2 is provided on the substrate 1. In the case of a photoelectric conversion element for an image sensor in which light passes through the first electrode 2 and is incident on the photoelectric conversion layer, it is preferable that the first electrode 2 has high transmittance with respect to the wavelength of the incident light (for example, transmittance of 80% or more, preferably transmittance of 90% or more).

[0087] The transparent material used for the first electrode 2 is not particularly limited. From the viewpoint of excellent light transmittance, the material constituting the first electrode 2 may be, for example, 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, metal sulfides such as zinc sulfide, etc.

[0088] In the case of a photoelectric conversion element for an image sensor in which light is incident on the photoelectric conversion layer only from the second electrode 7 side, the transmission characteristics of the first electrode 2 are not important. Therefore, examples of materials that can be used for the first electrode 2 in this case include sodium, sodium-potassium alloy, magnesium, lithium, magnesium / copper mixture, silver, gold, magnesium / silver mixture, aluminum, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al2O3) mixture, indium, lithium / aluminum mixture, iridium, molybdenum, palladium, platinum, and rare earth metals.

[0089] [Electron transport layer (hole blocking layer) 3] An electron transport layer (hole blocking layer) 3 is provided between the first electrode 2 and the photoelectric conversion layer 4.

[0090] The electron transport layer (hole blocking layer) 3 has the role of transporting electrons generated in the photoelectric conversion layer 4 to the lower electrode 2, and the role of blocking holes generated in the photoelectric conversion layer 4 from moving to the first electrode 2.

[0091] The electron transport layer (hole blocking layer) 3 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 electron transport layer (hole blocking layer) 3 may be a two-layer structure including, for example, a layer adjacent to the photoelectric conversion layer 4 made of a material specialized for hole blocking, and a layer adjacent to the first electrode 2 made of a material specialized for electron transport.

[0092] The electron transport layer (hole blocking layer) 3 may be a layer containing a conventionally known electron transport material. Examples of conventionally known electron transport materials include 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-quinolinolate)-4-(phenylphenolate)aluminum), 4,6-bis(3,5-di(pyridine-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.

[0093] [Photoelectric conversion layer 4] A photoelectric conversion layer 4 is provided between the electron transport layer (hole blocking layer) 3 and the hole transport layer (electron blocking layer) 5, which will be described later. The photoelectric conversion layer 4 contains a material that has a photoelectric conversion function.

[0094] From the viewpoint of increasing photoelectric conversion efficiency, the photoelectric conversion layer 4 preferably contains at least two types of organic materials and at least three types of materials. The photoelectric conversion layer 4 may be a single-layer structure or a laminated structure consisting of multiple layers of the same or different compositions.

[0095] Materials used in the photoelectric conversion layer 4 include n-type semiconductors and p-type semiconductors. N-type semiconductors are acceptor-type organic semiconductors, and compounds that readily accept electrons and have high electron transport properties are used. P-type semiconductors are donor-type organic semiconductors, and compounds that readily donate electrons and have high hole transport properties are used. When multiple materials are used in the photoelectric conversion layer 4, possible combinations include, for example, an n-type semiconductor and a p-type semiconductor, an n-type semiconductor and a compound with lower acceptor properties than the n-type semiconductor, and a p-type semiconductor and a compound with lower donor properties than the p-type semiconductor. Each material may be used individually, or two or more materials may be used. The photoelectric conversion layer 4 may contain a dye compound that is excellent at absorbing specific light. The dye compound may be a compound with lower acceptor properties than the n-type semiconductor, or a compound with lower donor properties than the p-type semiconductor. In terms of increasing photoelectric conversion efficiency, it is desirable that the photoelectric conversion layer 4 contains a dye compound in addition to the n-type and p-type semiconductors.

[0096] Examples of compounds included in the photoelectric conversion layer 4 include coumarin and its derivatives, quinacridone and its derivatives, phthalocyanine and its derivatives, fullerene and its derivatives, azole derivatives such as imidazole, thiazole, thiadiazole, oxazole, oxadiazole, and triazole, naphthalenetetracarboxylic acid diimide, and hole transport materials. Among these, the photoelectric conversion layer 4 preferably contains fullerene and two compounds selected from the group consisting of phthalocyanine and its derivatives and hole transport materials, and more preferably contains fullerene, phthalocyanine derivatives, and hole transport materials.

[0097] The photoelectric conversion 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 photoelectric conversion layer 4, which consists of these materials, may be formed, for example, by vapor deposition using a mixed powder obtained by mixing the powders of each material, or by co-depositing each material in any proportion.

[0098] 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, boron subnaphthalocyanine chloride (SubNC), F6-SubPC-OC6F5, and Cl6-SubPC-OC6. Specific examples of fullerenes and their derivatives include

[60] fullerene,

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

[60] PCBM). The hole transport material may be any known hole transport material. Examples of 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, naphthiothiophene compounds, benzodithiophene compounds, benzothiophene compounds, naphthobisbenzothiophene compounds, crisenodithiophene compounds, benzothienobenzothiophene compounds, indolocarbazole compounds, and the like. Among these, fluorene compounds, naphthodithiophene compounds, naphthothienothiophene compounds, benzodifuran compounds, benzothiophene compounds, naphthobisbenzothiophene compounds, crisenodithiophene compounds, benzothienobenzothiophene compounds, and indolocarbazole compounds are preferred, with fluorene compounds, crisenodithiophene compounds, benzothienobenzothiophene compounds, and indolocarbazole compounds being more preferred.

[0099] Specific examples of hole transport materials include 9,9'-(9,9'-spirobi[9H-fluorene]-2,7'-diyl)bis[9H-carbazole], 2,7-diphenyl[1]benzothieno[3,2-b][1]benzothiophene (DiPh-BTBT), benzo[1,2-b:3,4-b':5,6-b'']trifuran compounds, benzo[1,2-b:3,4-b':5,6-b'']trithiophene compounds, naphtho[1,2-b:5,6-b']dithiophene, and naphtho[2,3-b]naphtho[2',3':4,5] Examples include thieno[2,3-d]thiophene, benzo[1,2-b:4,5-b']difuran, benzo[1,2-b:4,5-b']dithiophene, benzo[1,2-b:4,5-b']bis[1]benzothiophene, naphtho[1,2-b:5,6-b']bis[1]benzothiophene, criseno[1,2-b:8,7-b']dithiophene, [1]benzothieno[3,2-b][1]benzothiophene, compounds represented by the following formula (ic-1), compounds represented by the following formulas (ic-2) and (ic-3), etc.

[0100] [ka]

[0101] Furthermore, the material having the photoelectric conversion function described above may be contained only in the photoelectric conversion layer 4, or it may be contained in layers other than the photoelectric conversion layer 4. For example, layers adjacent to the photoelectric conversion layer 4 (electron transport layer (hole blocking layer) 3, hole transport layer (electron blocking layer) 5) may contain the material having the photoelectric conversion function.

[0102] [Hole transport layer (electron blocking layer) 5] A hole transport layer (electron blocking layer) 5 is provided between the photoelectric conversion layer 4 and the buffer layer 6, which will be described later.

[0103] The hole transport layer (electron blocking layer) 5 has the role of transporting holes generated in the photoelectric conversion layer 4 to the second electrode 7, and blocking electrons generated in the photoelectric conversion layer 4 from moving to the second electrode 7. The hole transport layer (electron blocking layer) 5 contains a compound represented by formula (1).

[0104] The hole transport layer (electron blocking layer) 5 may be a single layer structure consisting only of the compound represented by formula (1), a single layer structure consisting of two or more materials, or a laminated structure consisting of multiple layers of the same or different compositions. For example, the hole transport layer (electron blocking layer) 5 may be a two-layer structure including a layer adjacent to the photoelectric conversion layer 4 made of a material specialized for electron blocking, and a layer adjacent to the buffer layer 6 made of a material specialized for hole transport.

[0105] The hole transport layer (electron blocking layer) 5 may further contain conventionally known hole transport materials in addition to the compound represented by formula (1). Preferred compounds and specific examples of conventionally known hole transport materials are the same as those described in the section on photoelectric conversion layer 4.

[0106] [Buffer layer 6] A buffer layer 6 is provided between the hole transport layer (electron blocking layer) 5 and the second electrode 7, which will be described later. The buffer layer 6 is provided to promote hole transport from the hole transport layer (electron blocking layer) 5 to the second electrode 7. This promotion of hole transport is brought about by the hole transport material changing its internal electric field through interaction with the surrounding material. In addition, when the second electrode 7 is formed by sputtering, the buffer layer 6 plays a role in reducing damage to the organic layer (e.g., the hole transport layer (electron blocking layer) 5) during sputtering.

[0107] The material constituting the buffer layer 6 may be a known organic material, such as naphthalene-1,4,5,8-tetracarboxylic dianhydride (NTCDA) or its derivatives, or aromatic compounds having a cyano group such as 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (HATCN). Among these, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (HATCN) is preferred.

[0108] [Second electrode 7] A second electrode 7 is provided on the buffer layer 6. The material of the second electrode 7 is not particularly limited and may be sodium, sodium-potassium alloy, magnesium, lithium, magnesium / copper mixture, magnesium / silver mixture, aluminum, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al2O3) mixture, indium, lithium / aluminum mixture, silver, gold, molybdenum, palladium, platinum, and rare earth metals, etc. In the case of a photoelectric conversion element for an image sensor in which light is incident on the photoelectric conversion layer from the second electrode 7 side, the material constituting the second electrode 7 may be, for example, 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, metal sulfides such as zinc sulfide, etc.

[0109] [Method of forming each layer] Each layer other than the first electrode 2 and the second electrode 7 can be formed by thinning the material of the respective layer (and optionally, a binder resin or other material, a solvent, etc.) using known methods such as vacuum deposition, spin coating, casting, or the LB (Langmuir-Blodgett method). The thickness of each layer other than the first electrode 2 and the second electrode 7 is not particularly limited and can be appropriately selected depending on the situation. The thickness of each layer other than the first electrode 2 and the second electrode 7 is usually in the range of 5 nm to 5 μm.

[0110] The first electrode 2 and the second electrode 7 can be formed by thinning the electrode material using methods such as vapor deposition and sputtering. If the first electrode 2 and the second electrode 7 have patterns, the patterns can be formed, for example, via a mask of a desired shape. Alternatively, a thin film may be formed by vapor deposition, sputtering, etc., and then a pattern of a desired shape may be formed by photolithography.

[0111] The film thickness of the first electrode 2 and the second electrode 7 may be 1 μm or less, and is preferably between 10 nm and 200 nm.

[0112] The first electrode 2 and the second electrode 7 may be made of different materials as needed (this is also called an inverse structure). In this structure, the light passes through the second electrode 7 and enters the photoelectric conversion layer 4, resulting in a photoelectric conversion element for an image sensor.

[0113] In the above embodiments, the photoelectric conversion element for the image sensor preferably comprises a photoelectric conversion layer and a hole transport layer in that order between the first electrode and the second electrode, and the photoelectric conversion layer preferably contains fullerene.

[0114] The image sensor equipped with the photoelectric conversion element according to this embodiment can be applied, for example, to image sensors in digital cameras, digital video cameras, and image sensors built into mobile phones, etc. Although preferred embodiments of the present invention have been described above, the present invention is not limited to the above embodiments. [Examples]

[0115] The present invention will be described in more detail below based on examples, but the present invention is not to be limited in any way by these examples.

[0116] (Synthetic compounds 1-4) The compounds (A37), (A51), (A120), and (A55) mentioned above were used as synthetic compounds 1 to 4, respectively. Compounds (A37), (A51), (A120), and (A55) were synthesized according to the methods disclosed in Japanese Patent Publication No. 2015-513530, Japanese Patent Publication No. 2013-544757, Japanese Patent Publication No. 2007-119457, and Japanese Patent Publication No. 2023-48143, respectively.

[0117] (Comparative compounds 1-4) As comparative compounds 1 to 4, compounds (X1), (X2), (X3), and (X4), represented by the following formulas, were used. Compound (X1) was synthesized according to the method disclosed in Japanese Patent Publication No. 2019-034939. Compounds (X2) and (X3) were manufactured by Tokyo Chemical Industry Co., Ltd. Compound (X4) was synthesized according to the method disclosed in Japanese Patent Publication No. 7216701. [ka]

[0118] (Glass transition temperature) The glass transition temperatures of synthetic compounds 1-4 and comparative compounds 1-4 were measured using a DSC7020 from Hitachi High-Tech Science Corporation. The results are shown in Table 1.

[0119] (HOMO value, band gap, LUMO value) The HOMO values ​​and band gaps were calculated from the wavelength edges of the absorption spectra of the vapor-deposited films (100 nm thick films deposited on a quartz substrate at a rate of 0.10 nm / second) of synthetic compounds 1-4 and comparative compounds 1-4. The LUMO values ​​were also calculated from the HOMO values ​​and band gaps. The HOMO values ​​of the vapor-deposited films were measured using an airborne photoelectron spectrometer (AC-3) manufactured by RIKEN KEKI Co., Ltd., and the absorption spectra were measured using a UV-Vis-Near-Infrared Spectrophotometer (V-750) manufactured by JASCO Corporation. The results are shown in Table 1.

[0120] [Table 1]

[0121] (Example 1: Fabrication of a photoelectric conversion element for an image sensor using compound (A37)) As shown in Figure 1, a photoelectric conversion element 100 for an image sensor was fabricated having a stacked structure consisting of a substrate 1, a first electrode 2, an electron transport layer (hole blocking layer) 3, a photoelectric conversion layer 4, a hole transport layer (electron blocking layer) 5, a buffer layer 6, and a second electrode 7, and its characteristics were evaluated.

[0122] (Preparation of substrate 1 and first electrode 2) As a substrate with the first electrode on its surface, a glass substrate with a transparent ITO electrode was prepared, which had a 2 mm wide indium-tin (ITO) film (thickness 110 nm) patterned in stripes. Next, this substrate was cleaned with isopropyl alcohol and then surface-treated by ozone ultraviolet cleaning.

[0123] (Vacuum deposition) Each layer was deposited on a substrate that had undergone surface treatment after cleaning using the vacuum deposition method. Specifically, a glass substrate with ITO transparent electrodes was introduced into the vacuum deposition chamber, and a 7.0 × 10 -5 The pressure was reduced to Pa. Then, each layer was prepared in the following order. (1) Fabrication of electron transport layer (hole blocking layer) 3) A 10 nm film of sublimated and purified 4,6-bis(3,5-di(pyridine-4-yl)phenyl)-2-methylpyrimidine was deposited at a rate of 0.10 nm / second to create an electron transport layer (hole blocking layer) 3. (2) Fabrication of the photoelectric conversion layer 4 A photoelectric conversion layer 4 was fabricated by co-evaporating 2Ph-BTBT, F6-SubPc-OC6F5, and fullerene (C60) at a deposition rate ratio of 4:4:2 to a thickness of 200 nm. The deposition rate was 0.15 nm / second. (3) Fabrication of hole transport layer (electron blocking layer) 5 A hole transport layer 5 was fabricated by depositing a 10 nm film of the sublimation-purified compound (A37) at a rate of 0.10 nm / second. (4) Fabrication of buffer layer 6 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (HATCN), which was purified by sublimation, was deposited as a 10 nm film at a rate of 0.10 nm / second to create buffer layer 6.

[0124] (5) (Fabrication of the second electrode 7) A metal mask was positioned perpendicular to the ITO stripes on the substrate, and the second electrode 7 was deposited. Gold was deposited on the second electrode to a thickness of 80 nm. The gold deposition rate was 0.1 nm / second.

[0125] Using the method described above, the area is 4 mm 2 A photoelectric conversion element for an image sensor was fabricated. The thickness of each layer was measured using a stylus-type film thickness gauge (DEKTAK, Bruker). The fabricated element was sealed in a nitrogen atmosphere glove box with oxygen and moisture concentrations of 1 ppm or less. Sealing was performed using a glass sealing cap and bisphenol F type epoxy resin (Nagase ChemteX).

[0126] (Example 2) The photoelectric conversion element for the image sensor in Example 2 was fabricated in the same manner as in Example 1, except that compound (A51) was used instead of compound (A37) in the fabrication of the hole transport layer 104 in Example 1.

[0127] (Example 3) The photoelectric conversion element for the image sensor in Example 3 was fabricated using the same method as in Example 1, except that compound (A120) was used instead of compound (A37) in the fabrication of the hole transport layer 104 in Example 1. (Example 4) The photoelectric conversion element for the image sensor in Example 3 was fabricated using the same method as in Example 1, except that compound (A55) was used instead of compound (A37) in the fabrication of the hole transport layer 104 in Example 1.

[0128] (Comparative Example 1) The photoelectric conversion element for the image sensor of Comparative Example 1 was fabricated in the same manner as in Example 1, except that compound (X1) was used instead of compound (A37) in the fabrication of the hole transport layer 104 of Example 1.

[0129] (Comparative Example 2) The photoelectric conversion element for the image sensor of Comparative Example 2 was fabricated in the same manner as in Example 1, except that compound (X2) was used instead of compound (A37) in the fabrication of the hole transport layer 104 of Example 1.

[0130] (Comparative Example 3) The photoelectric conversion element for the image sensor of Comparative Example 3 was fabricated in the same manner as in Example 1, except that compound (X3) was used instead of compound (A37) in the fabrication of the hole transport layer 104 of Example 1. (Comparative Example 4) The photoelectric conversion element for the image sensor of Comparative Example 3 was fabricated in the same manner as in Example 1, except that compound (X4) was used instead of compound (A37) in the fabrication of the hole transport layer 104 of Example 1.

[0131] (Measurement of dark current and response time) The current (dark current) and response time in the dark were evaluated when a voltage of 2.5V (absolute value) was applied to the image sensor photoelectric conversion element fabricated as described above, such that electrons were transported to the first electrode 2 and holes to the second electrode 7. The dark current was evaluated using a Keithley 2636B source measure unit. The response time was measured by irradiating with a light pulse and measuring the time until the current value returned to the pre-irradiation value.

[0132] The results are shown in Table 2. Note that the results in Table 2 are relative values, with the results in Comparative Example 1 set as the baseline value (1.00). A lower dark current value indicates better performance, and a shorter response time indicates better performance.

[0133] [Table 2]

[0134] As shown in Table 2, the elements in the examples using specific photoelectric conversion element materials for image sensors exhibited suppressed dark current and superior responsiveness compared to the elements in the comparative examples. [Explanation of symbols]

[0135] 1 circuit board 2. First electrode 3. Electron transport layer (hole blocking layer) 4. Photoelectric conversion layer 5. Hole transport layer (electron blocking layer) 6 Buffer Layers 7. Second electrode 100 Photoelectric conversion elements for image sensors< / l>

Claims

1. A photoelectric conversion element for an image sensor, comprising a photoelectric conversion layer and a hole transport layer between a first electrode and a second electrode, The photoelectric conversion layer comprises at least two types of organic materials, The hole transport layer contains a compound represented by the following formula (1): A photoelectric conversion element for image sensors. 【Chemistry 1】 (In formula (1), Ar １ ~Ar ４ Each of these is independently an aromatic hydrocarbon group having 6 to 30 carbon atoms, which may be substituted, a monocyclic, linked, or fused ring of 4 or fewer rings; a heteroaryl group having 3 to 30 carbon atoms, which may be substituted, which contains only one heteroatom; or a group combining these. R １１ ~R １２ Each of these is independently a nitro group, a halogen atom, an alkyl halide, an acyl group, a sulfonyl group, a phosphoryl group, an amino group, an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 1 to 20 carbon atoms, a cycloalkyl group having 1 to 20 carbon atoms, a bicycloalkyl group having 1 to 20 carbon atoms, a tricycloalkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 30 carbon atoms, a heteroaryl group having 3 to 30 carbon atoms, or a group consisting of a combination thereof. L is an aromatic hydrocarbon group having 6 to 30 carbon atoms, which may be directly bonded or substituted, which is a monocyclic, linked, or fused ring of 4 or fewer rings; which is a heteroaryl group having 3 to 30 carbon atoms, which may be substituted, which is a monocyclic, linked, or fused ring of 4 or fewer rings; or a group that is a combination thereof. Ar １ and Ar ２ Ar ３ and L, Ar ４ And L may be bonded to each other to form a ring. Ar １ ~Ar ４ When any of the aromatic hydrocarbon group represented by, the heteroaryl group, the aromatic hydrocarbon group represented by L, and the heteroaryl group has a substituent, the substituent is independently a nitro group, a halogen atom, a halogenated alkyl group, an acyl group, a sulfonyl group, a phosphoryl group, an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 1 to 20 carbon atoms, a cycloalkyl group having 1 to 20 carbon atoms, a bicycloalkyl group having 1 to 20 carbon atoms, a tricycloalkyl group having 1 to 20 carbon atoms, or an alkoxy group having 1 to 10 carbon atoms, m and n represent integers between 0 and 3.

2. Ar ３ and Ar ４ The photoelectric conversion element for an image sensor according to claim 1, wherein the base is represented by the following formula (2). 【Chemistry 2】 (In formula (2), R １ ~R ２ and R ４ ~R ５ Each of these is independently a hydrogen atom, a nitro group, a halogen atom, an alkyl halide, an acyl group, a sulfonyl group, a phosphoryl group, an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 1 to 20 carbon atoms, a cycloalkyl group having 1 to 20 carbon atoms, a bicycloalkyl group having 1 to 20 carbon atoms, a tricycloalkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 24 carbon atoms that is monocyclic, linked, or fused with 4 or fewer rings, a heteroaryl group having 3 to 24 carbon atoms that contains only one heteroatom, or a group that is a combination thereof. R ３ These are nitro groups, halogen atoms, alkyl halides, acyl groups, sulfonyl groups, phosphoryl groups, alkyl groups having 1 to 20 carbon atoms, alkenyl groups having 1 to 20 carbon atoms, cycloalkyl groups having 1 to 20 carbon atoms, bicycloalkyl groups having 1 to 20 carbon atoms, tricycloalkyl groups having 1 to 20 carbon atoms, alkoxy groups having 1 to 10 carbon atoms, monocyclic, linked, or fused ring groups of 6 to 24 carbon atoms, heteroaryl groups having 3 to 24 carbon atoms, monocyclic, or fused ring groups of 4 or fewer rings, containing only one heteroatom, or groups combining these. R １ ~R ５ These may be linked together to form a fused ring of formula (2) with four or fewer rings.

3. Ar ３ and Ar ４ The photoelectric conversion element for an image sensor according to claim 1, wherein the aromatic hydrocarbon group is a monocyclic, linked, or fused ring of four or fewer rings having 6 to 24 carbon atoms, which may be substituted.

4. Ar １ ~Ar ４ , R １１ ~R １２ The photoelectric conversion element for an image sensor according to claim 1, wherein the aromatic hydrocarbon group in L is a group formed from a five-membered ring and / or a six-membered ring.

5. Ar １ ~Ar ４ , R １１ ~R １２ The photoelectric conversion element for an image sensor according to claim 1, wherein the heteroaryl group in L is a carbazolyl group or a group containing a carbazolyl group.

6. Ar １ and Ar ２ The photoelectric conversion element for an image sensor according to claim 1, wherein the aromatic hydrocarbon group is a monocyclic or fused ring of four or fewer rings having 6 to 12 carbon atoms, which may be substituted.

7. The photoelectric conversion element for an image sensor according to claim 1, wherein L is a monocyclic or fused ring of 4 or fewer rings, aromatic hydrocarbon group, or carbazolediyl group, having 6 to 18 carbon atoms, which may be directly bonded or substituted.

8. A photoelectric conversion element for an image sensor according to claim 1, wherein m and n are 0.

9. A photoelectric conversion element for an image sensor according to claim 1, wherein formula (1) is represented by the following formula (3). 【Transformation 3】 (In the formula, Ar ３ ~Ar ４ , R １１ ~R １２ L, m, and n are the same as in equation (1). p represents either 0 or 1. When p is 0, it indicates that the phenyl groups on either side of (X)p are not directly bonded. (When p is 1, X represents a direct connection.)

10. A photoelectric conversion element for an image sensor according to claim 1, wherein the photoelectric conversion layer comprises at least three materials.

11. Between the first electrode and the second electrode, a photoelectric conversion layer, a hole transport layer, and a buffer layer are provided in this order. The buffer layer contains an organic material. A photoelectric conversion element for an image sensor according to claim 1.

12. The photoelectric conversion element for an image sensor according to claim 1, wherein the photoelectric conversion layer includes a fullerene.

Images