Material for photoelectric conversion element for image sensor and photoelectric conversion element for image sensor

Abstract

Provided is a photoelectric conversion element material that is for an imaging element and that contributes to production of a photoelectric conversion element that is for an imaging element and that exhibits excellent dark current and external quantum efficiency.　The present invention uses a photoelectric conversion element material that is for an imaging element and that contains a compound including a backbone that has a cove region in the molecular structure thereof and that optionally includes a substitution. However, examples of the compound does not include unsubstituted dibenzo[g,p]chrysene.　Preferable as the abovementioned material is a photoelectric conversion element material that is for an imaging element and that has a specific structure represented by formula (1).

Description

[Technical Field]

[0001] The present invention relates to a material for a photoelectric conversion element for an imaging device and a photoelectric conversion element for an imaging device. [Background technology]

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

[0003] In recent years, market demand for photoelectric conversion elements for image sensors has been increasing, and materials that are excellent in terms of dark current, external quantum efficiency, and response speed are being sought. Under these circumstances, the possibility of various polycyclic compounds as the mother nucleus of new materials has been continuously explored and studied. As polycyclic compounds, Patent Document 1 discloses derivatives with benzothienobenzothiophene as the mother nucleus. Furthermore, Patent Document 2 discloses various mother nuclei in addition to benzothienobenzothiophene. Patent Document 3 discloses unsubstituted dibenzo[g,p]chrysene. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2015 / 163349 [Patent Document 2] International Publication No. 2020 / 022421 [Patent Document 3] Japanese Patent Application Laid-Open No. 2010-258438 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of one embodiment of the present invention is to propose a material for a photoelectric conversion element for an imaging device and a photoelectric conversion element for an imaging device using a compound having a new mother nucleus, while the possibility of using various polycyclic compounds as the mother nucleus of a new material is being explored and examined.

[0006] Another object of the present invention is to provide a photoelectric conversion element material for an image sensor, a transport material for a photoelectric conversion element for an image sensor, and a hole transport material for a photoelectric conversion element for an image sensor, which are useful for fabricating a photoelectric conversion element for an image sensor having low dark current and high external quantum efficiency. Another object of the present invention is to provide a photoelectric conversion element for an image sensor having low dark current and high external quantum efficiency. Incidentally, Patent Document 3 describes the use of unsubstituted dibenzo[g,p]chrysene as a crystalline layer between a photoelectric conversion layer and an upper electrode. However, Patent Document 3 makes no mention of the molecular structural characteristics of dibenzo[g,p]chrysene or an amorphous film containing dibenzo[g,p]chrysene. In addition, the dibenzo[g,p]chrysene described in Patent Document 3 does not provide any knowledge on improving the performance of a photoelectric conversion element for an imaging device. [Means for solving the problem]

[0007] According to one aspect of the present invention, there is provided a material for a photoelectric conversion element for an imaging device, the material comprising a compound having a skeleton with a cove region in its molecular structure, the skeleton being optionally substituted, with the proviso that the compound does not include dibenzo[g,p]chrysene.

[0008] According to another aspect of the present invention, there is provided a material for a photoelectric conversion element for an imaging element, the skeleton of which is represented by the following formula (1):

[0009] [ka]

[0010] In formula (1), X 1 ~X 4 each independently represents a hydrogen atom or a substituent; X 1 ~X 4 do not combine with each other to form a ring; Multiple Xs 1 ~X 4may be the same or different; Z 1 ~Z 8 each independently represents a nitrogen atom or a carbon atom which may have a substituent; Z 1 ~Z 8 at least six of which are carbon atoms which may have a substituent; Multiple Zs 1 ~Z 8 may be the same or different; Z 1 ~Z 8 is a carbon atom which may have a substituent, one or two Z adjacent to the carbon atom 1 ~Z 8 They may be bonded to the substituents on any carbon atom to form a ring.

[0011] According to another aspect of the present invention, there is provided a material for a photoelectric conversion element for an imaging element according to the above aspect, which is a transport material for a photoelectric conversion element for an imaging element or a charge blocking material for a photoelectric conversion element for an imaging element. According to another aspect of the present invention, there is provided the material for a photoelectric conversion element for an imaging element according to the above aspect, which is a hole transport material for a photoelectric conversion element for an imaging element or an electron blocking material for a photoelectric conversion element for an imaging element. According to another aspect of the present invention, there is provided a photoelectric conversion element for an imaging device, including the material for a photoelectric conversion element for an imaging device according to the above aspect. [Effects of the Invention]

[0012] According to one embodiment of the present invention, it is possible to provide a material for a photoelectric conversion element for an image sensor, a hole transport material for a photoelectric conversion element for an image sensor, and an electron blocking material for a photoelectric conversion element for an image sensor, which are useful for producing a photoelectric conversion element for an image sensor having excellent dark current and external quantum efficiency.

[0013] According to another aspect of the present invention, it is possible to provide a photoelectric conversion element for an image sensor that is excellent in dark current and external quantum efficiency. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a schematic cross-sectional view showing an example of a layer structure of a photoelectric conversion element for an imaging element including a material for a photoelectric conversion element for an imaging element according to one aspect of the present invention. [Figure 2] FIG. 2 is a schematic cross-sectional view showing the layered structure of element example A-1. [Figure 3] FIG. 1 is a schematic cross-sectional view showing the layered structure of element example B-1. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, a material for a photoelectric conversion element for an imaging element according to one embodiment of the present invention will be described in detail.

[0016] <Photoelectric conversion element materials for imaging devices> One aspect of the present invention is a material for a photoelectric conversion element for an imaging device, which includes a compound having a skeleton with a cove region in its molecular structure, and the skeleton may be substituted, but the compound does not include unsubstituted dibenzo[g,p]chrysene. The cove region is a term that refers to a specific molecular structure region in a polycyclic compound, and refers to a region disclosed in, for example, a non-patent document (Chemical Science, 2019, 10, 4025.). Note that, in this specification, the term "material" also includes compounds.

[0017] The cove region refers to a bay-shaped cut-out region formed by the four sides of each benzene ring in a [4]helicene skeleton formed by four fused benzene rings. The material for a photoelectric conversion element for an imaging device may have at least one hydrogen atom and one carbon atom substituted in the [4]helicene skeleton having the cove region. The [4]helicene skeleton also includes a heterohelicene skeleton in which a portion of the benzene ring is replaced with a heterocycle. When the material for a photoelectric conversion element for an imaging device includes a heterohelicene skeleton having a cove region, at least one hydrogen atom, carbon atom, oxygen atom, sulfur atom, and nitrogen atom in the heterohelicene skeleton may be substituted. In the embodiment in which the skeleton having the cove region is substituted, the substituent of the skeleton is preferably a charge-transporting substituent. Details of the charge-transporting substituent will be described later, and the specific substituent described later can be used as is in this embodiment as well. Although the [5]helicene skeleton, which has five fused benzene rings, and the [6]helicene skeleton, which has six fused benzene rings, can also be considered to partially contain cove regions, these are regions called fjord regions, and do not fall under the category of cove regions.

[0018] The cove region in the present invention refers to a region possessed by a compound represented by formula (1), and more specifically, refers to a region indicated by a bold line in formula (1'). That is, one embodiment of the present invention is preferably a material for a photoelectric conversion element for an imaging device, which includes a compound having a skeleton represented by formula (1) and which may be substituted, provided that the compound does not include unsubstituted dibenzo[g,p]chrysene.

[0019] [ka]

[0020] In formula (1), X 1 ~X 4 each independently represents a hydrogen atom or a substituent; X 1 ~X 4 do not combine with each other to form a ring; Multiple Xs 1 ~X 4 may be the same or different; Z 1 ~Z 8 each independently represents a nitrogen atom or a carbon atom which may have a substituent; Z 1 ~Z 8 at least six of which are carbon atoms which may have a substituent; Multiple Zs 1 ~Z 8may be the same or different; Z 1 ~Z 8 is a carbon atom which may have a substituent, one or two Z adjacent to the carbon atom 1 ~Z 8 They may be bonded to the substituents on any carbon atom to form a ring.

[0021] The definitions and preferred specific examples of the above formula (1) are as follows: <X 1 ~X 4 About > X 1 ~X 4 Each of X independently represents a hydrogen atom or a substituent. 1 ~X 4 do not form a ring with each other, and by not forming a ring, the above-mentioned cove region is present in the molecular structure. 1 and X 2 are preferably all hydrogen atoms. <Z 1 ~Z 8 About > Z 1 ~Z 8 Z each independently represents a nitrogen atom or a carbon atom which may have a substituent. 1 ~Z 8 Among these, it is preferred that at least six of them are carbon atoms which may have a substituent, it is more preferred that at least seven of them are carbon atoms which may have a substituent, and it is particularly preferred that all of them are carbon atoms which may have a substituent. 3 and Z 4 is a carbon atom which may have a substituent, and Z 3 and Z 4 It is preferred that the substituents are bonded to each other to form a ring.

[0022] More specifically, the material for a photoelectric conversion element for an imaging element according to one embodiment of the present invention preferably contains a compound represented by any one of the following formulas (2A) to (5B). [ka]

[0023] [ka]

[0024] In formulas (2A) to (5B), A represents a charge-transporting substituent; Ar2 represents a monocyclic, linked, or fused ring aromatic hydrocarbon group having 6 to 30 carbon atoms which may have a substituent, a monocyclic, linked, or fused ring heteroaromatic group having 3 to 36 carbon atoms which may have a substituent, or a linear or branched alkyl group having 1 to 18 carbon atoms; R 1 and R 2 are each independently hydrogen atoms; deuterium atoms; a monocyclic, linked, or fused ring aromatic hydrocarbon group having 6 to 30 carbon atoms which may have a substituent; a monocyclic, linked, or fused ring heteroaromatic group having 3 to 36 carbon atoms which may have a substituent; A linear or branched alkyl group having 1 to 18 carbon atoms; or a linear or branched alkoxy group having 1 to 18 carbon atoms; R 1 and R 2 may be bonded to each other to form a ring. k represents an integer from 1 to 4; Multiple A's may be the same or different.

[0025] The definitions of the charge transporting substituents in the materials (2A) to (5B) for photoelectric conversion elements for imaging elements and preferred specific examples thereof are as follows.

[0026] <Charge-transporting substituents> A charge-transporting substituent is a substituent that has the function of transporting charges, which can be holes, electrons, or both.

[0027] Examples of the charge transporting substituent include the following substituents (a-1) to (a-16). (a-1) a deuterium atom, (a-2) a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, (a-3) a trifluoromethyl group, (a-4) a pentafluoroethyl group, (a-5) a cyano group, (a-6) a nitro group, (a-7) hydroxyl group, (a-8) a thiol group, (a-9) a monocyclic, linked, or fused ring aromatic hydrocarbon group having 6 to 30 carbon atoms which may have a substituent; (a-10) a monocyclic, linked, or fused ring heteroaromatic group having 3 to 36 carbon atoms which may have a substituent; (a-11) a phosphine oxide group which may have a substituent, (a-12) a silyl group which may have a substituent, (a-13) a boronyl group which may have a saturated hydrocarbon group having 2 to 10 carbon atoms, (a-14) a linear or branched alkyl group having 1 to 18 carbon atoms, (a-15) a linear or branched alkoxy group having 1 to 18 carbon atoms, (a-16) a trifluoromethylsulfonyloxy group, or (a-17) A group represented by the following formula (6) or (6'):

[0028] [ka] During the ceremony, R 100 ~R 300 are each independently (r-1) hydrogen atom, (r-2) deuterium atom, (r-3) a monocyclic, linked, or fused ring aromatic hydrocarbon group having 6 to 30 carbon atoms which may have a substituent; (r-4) a monocyclic, linked, or fused ring heteroaromatic group having 3 to 36 carbon atoms which may have a substituent, or (r-5) represents a linear or branched alkyl group having 1 to 18 carbon atoms; L is independently a phenylene group optionally substituted with a methyl group or a phenyl group; a naphthylene group optionally substituted with a methyl group or a phenyl group; a biphenylene group optionally substituted with a methyl group or a phenyl group, or represents a single bond; n represents 1 or 2; When L is a single bond, n is 1; When L is not a single bond, n is 1 or 2; If n is 2, multiple R 100 ~R 200 may be the same or different.

[0029] <Regarding (a-9)> Examples of (a-9) monocyclic, linked, or fused ring aromatic hydrocarbon groups having 6 to 30 carbon atoms include phenyl, biphenylyl, terphenylyl, naphthyl, fluorenyl, anthryl, phenanthryl, benzofluorenyl, triphenylenyl, spirobifluorenyl, diphenylfluorenyl, dibenzo[g,p]chrysenyl, etc. Furthermore, the monocyclic, linked, or fused ring aromatic hydrocarbon groups having 6 to 30 carbon atoms are preferably monocyclic, linked, or fused ring aromatic hydrocarbon groups having 6 to 18 carbon atoms.

[0030] When the aromatic hydrocarbon group of (a-9) has a substituent, the substituents are preferably each independently a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a nitro group, a hydroxyl group, a thiol group, a phosphine oxide group which may have a substituent, a silyl group which may have a substituent, a boronyl group which may have a saturated hydrocarbon group having 2 to 10 carbon atoms, a linear or branched alkyl group having 1 to 18 carbon atoms, a linear or branched alkoxy group having 1 to 18 carbon atoms, or a trifluoromethylsulfonyloxy group.

[0031] The phosphine oxide group may be an unsubstituted phosphine oxide group or a substituted phosphine oxide group, with a substituted phosphine oxide group being preferred.

[0032] The substituted phosphine oxide group is preferably a phosphine oxide group having a monocyclic, linked, or fused ring aromatic hydrocarbon group or a fused ring heteroaromatic group having 6 to 18 carbon atoms. Specific examples include groups substituted with two aryl groups, such as diphenylphosphine oxide.

[0033] The silyl group may be an unsubstituted silyl group or a substituted silyl group, with a substituted silyl group being preferred.

[0034] The silyl group having a substituent is preferably a silyl group having a monocyclic, linked, or fused ring aromatic hydrocarbon group or a fused ring heteroaromatic group having 6 to 18 carbon atoms. Specific examples include groups substituted with three aryl groups, such as a triphenylsilyl group.

[0035] Examples of the boronyl group which may have a saturated hydrocarbon group having 2 to 10 carbon atoms include a dihydroxyboryl group (-B(OH)2), a 4,4,5,5-tetramethyl-[1,3,2]-dioxaborolanyl group, and a 5,5-dimethyl-[1,3,2]-dioxaborinane group.

[0036] Examples of the linear or branched alkyl group having 1 to 18 carbon atoms 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, and an octadecyl group.

[0037] Examples of the linear or branched alkoxy group having 1 to 18 carbon atoms include a methoxy group, an ethoxy group, an n-propoxy group, an i-propoxy group, an n-butoxy group, a sec-butoxy group, a tert-butoxy group, a pentyloxy group, an n-hexyloxy group, a cyclohexyloxy group, an octyloxy group, a decyloxy group, a dodecyloxy group, and an octadecyloxy group.

[0038] <About (a-10)> The monocyclic, linked, or fused ring heteroaromatic group having 3 to 36 carbon atoms (a-10) is a monocyclic, linked, or fused ring heteroaromatic group having 3 to 36 carbon atoms and containing at least one atom selected from the group consisting of an oxygen atom, a nitrogen atom, and a sulfur atom on the aromatic ring.

[0039] Examples of the heteroaromatic group include a pyrrolyl group, a thienyl group, a furyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a pyridyl group, a phenylpyridyl group, a pyridylphenyl group, a pyrimidyl group, a pyrazyl group, a 1,3,5-triazyl group, a 1,3,5-triazylphenyl group, a 1,3,5-triazylbiphenylyl group, a 4,6-diphenyl-1,3,5-triazyl group, an indolyl group, a benzothienyl group, a benzofuranyl group, a benzimidazolyl group, a benzophenone ... Examples of such groups include an aryl group, an indazolyl group, a benzothiazolyl group, a benzisothiazolyl group, a 2,1,3-benzothiadiazolyl group, a benzoxazolyl group, a benzisoxazolyl group, a 2,1,3-benzoxadiazolyl group, a quinolyl group, an isoquinolyl group, a quinoxalyl group, a quinazolyl group, a carbazolyl group, a 9-phenylcarbazolyl group, a 9-(4-biphenylyl)carbazolyl group, a dibenzothienyl group, a dibenzofuranyl group, a phenoxazinyl group, a phenothiazinyl group, a phenazine group, and a thianthrenyl group.

[0040] In addition, when the heteroaromatic group of (a-10) has a substituent, the substituent is preferably each independently a cyano group, a fluorine atom, a trifluoromethyl group, a linear or branched alkyl group having 1 to 18 carbon atoms, a linear or branched alkoxy group having 1 to 18 carbon atoms, or a trifluoromethylsulfonyloxy group.

[0041] Examples of the linear or branched alkyl group having 1 to 18 carbon atoms include the same linear or branched alkyl groups having 1 to 18 carbon atoms as exemplified in (a-9) above. Examples of the linear or branched alkoxy group having 1 to 18 carbon atoms include the same linear or branched alkoxy groups having 1 to 18 carbon atoms as exemplified in (a-9) above.

[0042] <About (a-11)> The phosphine oxide group (a-11) may be an unsubstituted phosphine oxide group or a substituted phosphine oxide group, preferably a substituted phosphine oxide group. Examples of the substituted phosphine oxide group include the same phosphine oxide groups as exemplified in (a-9) above.

[0043] <Regarding (a-12)> The silyl group (a-12) may be an unsubstituted silyl group or a silyl group having a substituent. A silyl group having a substituent is preferred. Examples of the silyl group having a substituent include the same silyl groups as those exemplified in (a-9) above.

[0044] <About (a-13)> Examples of the boronyl group (a-13) which may have a saturated hydrocarbon group having 2 to 10 carbon atoms and the boronyl group (a-13) which may have a saturated hydrocarbon group having 2 to 10 carbon atoms include the same boronyl groups as exemplified in (a-9) above.

[0045] <Regarding (a-14)> Examples of the linear alkyl group having 1 to 18 carbon atoms (a-14) include the same linear or branched alkyl groups having 1 to 18 carbon atoms as exemplified above in (a-9).

[0046] <About (a-15)> Examples of the linear or branched alkoxy group having 1 to 18 carbon atoms (a-15) include the same linear or branched alkoxy groups having 1 to 18 carbon atoms as exemplified in (a-9) above.

[0047] <About (a-17)> (a-17) is a group represented by formula (6) or (6'), and as described above, the charge transporting group may be a group represented by formula (6) or (6'). In formulas (6) and (6'), L, R 100 ~R 300 , n is defined as follows:

[0048] <Regarding formulas (6) and (6')> In formulas (6) and (6'), R 100 ~R 300 each independently represents (r-1) a hydrogen atom, (r-2) a deuterium atom, (r-3) an optionally substituted monocyclic, linked, or fused ring aromatic hydrocarbon group having 6 to 30 carbon atoms, (r-4) an optionally substituted monocyclic, linked, or fused ring heteroaromatic group having 3 to 36 carbon atoms, or (r-5) a linear or branched alkyl group having 1 to 18 carbon atoms. R 100 ~R 300 When R has a substituent, 100 ~R 300 may be substituted with one substituent or with two or more substituents.

[0049] The definition of the monocyclic, linked, or fused ring aromatic hydrocarbon group having 6 to 30 carbon atoms in (r-3) above is the same as the definition of the monocyclic, linked, or fused ring aromatic hydrocarbon group having 6 to 30 carbon atoms described in (a-9) above, except for the definition of the substituent.

[0050] When the aromatic hydrocarbon group of (r-3) has a substituent, the substituent is preferably a deuterium atom, a fluorine atom, a linear or branched alkyl group having 1 to 18 carbon atoms, a linear or branched alkoxy group having 1 to 18 carbon atoms, a 9-carbazolyl group, a dibenzothienyl group, a dibenzofuranyl group, an N,N-diphenylamino group, or an N,N-bis(4-biphenylyl)-amino group.

[0051] Examples of the linear or branched alkyl group having 1 to 18 carbon atoms include the same linear alkyl groups having 1 to 18 carbon atoms as exemplified in (a-9) above. Examples of the linear or branched alkoxy group having 1 to 18 carbon atoms include the same linear or branched alkoxy groups having 1 to 18 carbon atoms as exemplified in (a-9) above.

[0052] The definition of the monocyclic, linked, or fused ring heteroaromatic group having 3 to 36 carbon atoms in (r-4) above is the same as that of the monocyclic, linked, or fused ring heteroaromatic group having 3 to 36 carbon atoms exemplified in (a-10) above, except for the definition of the substituent. Furthermore, a monocyclic, linked, or fused ring heteroaromatic group having 3 to 20 carbon atoms is more preferred.

[0053] When the heteroaromatic group (r-4) has a substituent, the substituent is preferably a deuterium atom, a fluorine atom, a linear or branched alkyl group having 1 to 18 carbon atoms, a linear or branched alkoxy group having 1 to 18 carbon atoms, a 9-carbazolyl group, a dibenzothienyl group, a dibenzofuranyl group, an N,N-diphenylamino group, or an N,N-bis(4-biphenylyl)-amino group. These substituents have the same definition as, for example, the substituent of (r-3) described above.

[0054] The definition of the linear or branched alkyl group having 1 to 18 carbon atoms in (r-5) above is the same as that shown in (a-9) above.

[0055] In formulas (6) and (6'), L represents a phenylene group which may be substituted with a methyl group or a phenyl group; a naphthylene group which may be substituted with a methyl group or a phenyl group; a biphenylene group which may be substituted with a methyl group or a phenyl group; or a single bond.

[0056] Examples of the phenylene group include a 1,2-phenylene group, a 1,3-phenylene group, and a 1,4-phenylene group.

[0057] Examples of the naphthylene group include a naphthalene-1,2-diyl group, a naphthalene-1,4-diyl group, a naphthalene-1,8-diyl group, and a naphthalene-2,3-diyl group.

[0058] Examples of the biphenylene group include a biphenyl-4,4'-diyl group, a biphenyl-4,3'-diyl group, a biphenyl-4,2'-diyl group, a biphenyl-3,3'-diyl group, a biphenyl-3,2'-diyl group, and a biphenyl-2,2'-diyl group.

[0059] In formulas (6) and (6'), n represents an integer of 1 or 2. When L is a single bond, n is an integer of 1. When L is not a single bond, n is an integer of 1 or 2. Note that when n is 2, R 100 and R 200 There are two of each, and they may be the same or different.

[0060] <R 1 , R 2 About > R 1 and R 2 When (b-3) is an aromatic hydrocarbon group having a substituent, or (b-4) is a heteroaromatic group having a substituent, the substituents are preferably each independently a deuterium atom, a fluorine atom, a linear or branched alkyl group having 1 to 18 carbon atoms, or a linear or branched alkoxy group having 1 to 18 carbon atoms. Specific examples of the linear or branched alkyl group having 1 to 18 carbon atoms and the linear or branched alkoxy group having 1 to 18 carbon atoms are not particularly limited, but include the same as those exemplified above in (a-9).

[0061] R 1 and R 2 may be bonded to each other to form a ring. For example, R 1 and R 2 When is phenyl, they can be linked together to form a fluorene ring.

[0062] (b-3): a monocyclic, linked, or fused ring aromatic hydrocarbon group having 6 to 30 carbon atoms, which may have a substituent; R in formulas (4A) to (4C) 1 and R 2In the formula (I), the monocyclic, linked, or fused ring aromatic hydrocarbon group having 6 to 30 carbon atoms, which may have a substituent, is not particularly limited, but examples thereof include a phenyl group and a biphenylyl group.

[0063] (b-4): a monocyclic, linked, or fused ring heteroaromatic group having 3 to 36 carbon atoms, which may have a substituent. R in formulas (4A) to (4C) 1 and R 2 In the above, the monocyclic, linked or fused ring heteroaromatic group having 3 to 36 carbon atoms is not particularly limited, but examples thereof include a pyridyl group.

[0064] (b-5): A linear or branched alkyl group having 1 to 18 carbon atoms In the formulae (4A) to (4C), examples of the linear or branched alkyl group having 1 to 18 carbon atoms include the same linear or branched alkyl groups having 1 to 18 carbon atoms as exemplified in (a-9) above.

[0065] (b-6): A linear or branched alkoxy group having 1 to 18 carbon atoms In the formulae (4A) to (4C), examples of the linear or branched alkoxy group having 1 to 18 carbon atoms include the same linear or branched alkoxy groups having 1 to 18 carbon atoms as exemplified in (a-9) above.

[0066] In the fused ring compounds represented by formulas (4A) to (4C), R 1 and R 2 are independently ranked in terms of ease of obtaining raw materials. a phenyl group, a biphenylyl group, a pyridyl group, a pyrimidyl group, or any of these groups substituted with a methyl group or a methoxy group; A methyl group, an n-butyl group, or an n-hexyl group is preferred. Also, R 1 and R 2 are each independently a phenyl group or a group in which a phenyl group is substituted with a methyl group or a methoxy group; or A methyl group is more preferred.

[0067] <kについて> Each k is independently an integer of 0 to 4. When k is 2 or greater, a plurality of Ar are present, and the plurality of Ar may be the same or different.

[0068] k is preferably 3 or less, and more preferably 2 or less. When k is 3 or less, the molecular weight is smaller than that of a compound in which k is 4 or more. As a result, the sublimation temperature of the compound is lowered, and the heat resistance stability during sublimation is improved, which is preferable.

[0069] Specific examples of A include the following groups (1) to (24). (1): Methyl group, ethyl group, fluorine atom, chlorine atom, bromine atom, iodine atom, cyano group, nitro group, hydroxyl group, thiol group, deuterium atom, methoxy group, trifluoromethylsulfonyloxy group

[0070] (2): phenyl group, 4-methylphenyl group, 3-methylphenyl group, 2-methylphenyl group, 2,4-dimethylphenyl group, 2,5-dimethylphenyl group, 3,4-dimethylphenyl group, 3,5-dimethylphenyl group, 2,6-dimethylphenyl group, 2,3,5-trimethylphenyl group, 2,3,6-trimethylphenyl group, 2,4,6-trimethylphenyl group, 3,4,5-trimethylphenyl group, 4-hydroxyphenyl group, 3-hydroxy group, 2-hydroxyphenyl group, 3,5-dihydroxyphenyl group, 3,4-dihydroxyphenyl group, 4-methoxyphenyl group, 3-methoxyphenyl group, 2-methoxyphenyl group, 3,5-dimethoxyphenyl group, 3,4-dimethoxyphenyl group, 4-trifluoromethylsulfonyloxyphenyl group, 3-trifluoromethylsulfonyloxyphenyl group, 2-trifluoromethylsulfonyloxyphenyl group, 3,5-bis(trifluoromethylsulfonyloxy)phenyl group, 3,4-bis(trifluoromethylsulfonyloxy)phenyl group,

[0071] (3): 4-biphenyl group, 3-biphenyl group, 2-biphenyl group, 2-methyl-1,1'-biphenyl-4-yl group, 3-methyl-1,1'-biphenyl-4-yl group, 2'-methyl-1,1'-biphenyl-4-yl group, 3'-methyl-1,1'-biphenyl-4-yl group, 4'-methyl-1,1'-biphenyl-4-yl group, 2,6-dimethyl-1,1'-biphenyl-4-yl group, 2,2'-dimethyl-1,1'-biphenyl-4-yl group, 2,3'-dimethyl dimethyl-1,1'-biphenyl-4-yl group, 2,4'-dimethyl-1,1'-biphenyl-4-yl group, 3,2'-dimethyl-1,1'-biphenyl-4-yl group, 2',3'-dimethyl-1,1'-biphenyl-4-yl group, 2',4'-dimethyl-1,1'-biphenyl-4-yl group, 2',5'-dimethyl-1,1'-biphenyl-4-yl group, 2',6'-dimethyl-1,1'-biphenyl-4-yl group, 4-phenylbiphenyl group, 2-phenylbiphenyl group

[0072] (4): 1-naphthyl group, 2-naphthyl group, 2-methylnaphthalen-1-yl group, 4-methylnaphthalen-1-yl group, 6-methylnaphthalen-2-yl group, 4-(1-naphthyl)phenyl group, 4-(2-naphthyl)phenyl group, 3-(1-naphthyl)phenyl group, 3-(2-naphthyl)phenyl group, 3-methyl-4-(1-naphthyl)phenyl group, 3-methyl-4-(2-naphthyl)phenyl group, 4-(2-methylnaphthalen-1-yl)phenyl group, 3-( 2-methylnaphthalen-1-yl)phenyl group, 4-phenylnaphthalen-1-yl group, 4-(2-methylphenyl)naphthalen-1-yl group, 4-(3-methylphenyl)naphthalen-1-yl group, 4-(4-methylphenyl)naphthalen-1-yl group, 6-phenylnaphthalen-2-yl group, 4-(2-methylphenyl)naphthalen-2-yl group, 4-(3-methylphenyl)naphthalen-2-yl group, 4-(4-methylphenyl)naphthalen-2-yl group

[0073] (5): 2-fluorenyl group, 9,9-dimethyl-2-fluorenyl group, 9,9'-spirobifluorenyl group, 9-phenanthryl group, 2-phenanthryl group, 11,11'-dimethylbenzo[a]fluoren-9-yl group, 11,11'-dimethylbenzo[a]fluoren-3-yl group, 11,11'-dimethylbenzo[b]fluoren-9-yl group, 11,11'-dimethylbenzo[b]fluoren-3-yl group, 11,11'-dimethylbenzo[c]fluoren-9-yl group, 11,11'-dimethylbenzo[c]fluoren-2-yl group, 3-fluoranthenyl group, 8-fluoranthenyl group

[0074] (6): 1-imidazolyl group, 2-phenyl-1-imidazolyl group, 2-phenyl-3,4-dimethyl-1-imidazolyl group, 2,3,4-triphenyl-1-imidazolyl group, 2-(2-naphthyl)-3,4-dimethyl-1-imidazolyl group, 2-(2-naphthyl)-3,4-diphenyl-1-imidazolyl group, 1-methyl-2-imidazolyl group, 1-ethyl-2-imidazolyl group , 1-phenyl-2-imidazolyl group, 1-methyl-4-phenyl-2-imidazolyl group, 1-methyl-4,5-dimethyl-2-imidazolyl group, 1-methyl-4,5-diphenyl-2-imidazolyl group, 1-phenyl-4,5-dimethyl-2-imidazolyl group, 1-phenyl-4,5-diphenyl-2-imidazolyl group, 1-phenyl-4,5-dibiphenylyl-2-imidazolyl group

[0075] (7): 1-methyl-3-pyrazolyl group, 1-phenyl-3-pyrazolyl group, 1-methyl-4-pyrazolyl group, 1-phenyl-4-pyrazolyl group, 1-methyl-5-pyrazolyl group, 1-phenyl-5-pyrazolyl group

[0076] (8): 2-thiazolyl group, 4-thiazolyl group, 5-thiazolyl group, 3-isothiazolyl group, 4-isothiazolyl group, 5-isothiazolyl group (9): 2-oxazolyl group, 4-oxazolyl group, 5-oxazolyl group, 3-isoxazolyl group, 4-isoxazolyl group, 5-isoxazolyl group

[0077] (10): 2-pyridyl group, 3-methyl-2-pyridyl group, 4-methyl-2-pyridyl group, 5-methyl-2-pyridyl group, 6-methyl-2-pyridyl group, 3-pyridyl group, 4-methyl-3-pyridyl group, 4-pyridyl group, 2-pyrimidyl group, 2,2'-bipyridin-3-yl group, 2,2'-bipyridin-4-yl group, 2,2'-bipyridin-5-yl group, 2,3'-bipyridin-3-yl group, 2,3'-bipyridin-4-yl group, 2,3'-bipyridin-5-yl group, 5-pyrimidyl group, pyrazyl group, 1,3,5-triazyl group, 4,6-diphenyl-1,3,5-triazin-2-yl group

[0078] (11): 1-benzimidazolyl group, 2-methyl-1-benzimidazolyl group, 2-phenyl-1-benzimidazolyl group, 1-methyl-2-benzimidazolyl group, 1-phenyl-2-benzimidazolyl group, 1-methyl-5-benzimidazolyl group, 1,2-dimethyl-5-benzimidazolyl group, 1-methyl-2-phenyl-5-benzimidazolyl group, 1-phenyl-5-benzimidazolyl group, 1-methyl-6-benzimidazolyl group, 1,2-diphenyl-5-benzimidazolyl group, 1-methyl-6-benzimidazolyl group, 1,2-dimethyl-6-benzimidazolyl group, 1-methyl-2-phenyl-6-benzimidazolyl group, 1-phenyl-6-benzimidazolyl group, 1,2-diphenyl-6-benzimidazolyl group, 1-methyl-3-indazolyl group, 1-phenyl-3-indazolyl group

[0079] (12): 2-benzothiazolyl group, 4-benzothiazolyl group, 5-benzothiazolyl group, 6-benzothiazolyl group, 7-benzothiazolyl group, 3-benzoisothiazolyl group, 4-benzoisothiazolyl group, 5-benzoisothiazolyl group, 6-benzoisothiazolyl group, 7-benzoisothiazolyl group, 2,1,3-benzothiadiazol-4-yl group, 2,1,3-benzothiadiazol-5-yl group

[0080] (13): 2-benzoxazolyl group, 4-benzoxazolyl group, 5-benzoxazolyl group, 6-benzoxazolyl group, 7-benzoxazolyl group, 3-benzoisoxazolyl group, 4-benzoisoxazolyl group, 5-benzoisoxazolyl group, 6-benzoisoxazolyl group, 7-benzoisoxazolyl group, 2,1,3-benzoxadiazolyl-4-yl group, 2,1,3-benzoxadiazolyl-5-yl group

[0081] (14): 2-quinolyl group, 3-quinolyl group, 5-quinolyl group, 6-quinolyl group, 1-isoquinolyl group, 4-isoquinolyl group, 5-isoquinolyl group, 2-quinoxalyl group, 3-phenyl-2-quinoxalyl group, 6-quinoxalyl group, 2,3-dimethyl-6-quinoxalyl group, 2,3-diphenyl-6-quinoxalyl group, 2-quinazolyl group, 4-quinazolyl group, 2-acridinyl group, 9-acridinyl group, 1,10-phenanthrolin-3-yl group, 1,10-phenanthrolin-5-yl group

[0082] (15): 2-thienyl group, 3-thienyl group, 2-benzothienyl group, 3-benzothienyl group, 2-dibenzothienyl group, 4-dibenzothienyl group (16): 2-furanyl group, 3-furanyl group, 2-benzofuranyl group, 3-benzofuranyl group, 2-dibenzofuranyl group, 4-dibenzofuranyl group

[0083] (17): 9-methylcarbazol-2-yl group, 9-methylcarbazol-3-yl group, 9-methylcarbazol-4-yl group, 9-phenylcarbazol-2-yl group, 9-phenylcarbazol-3-yl group, 9-phenylcarbazol-4-yl group, 9-biphenylcarbazol-2-yl group, 9-biphenylcarbazol-3-yl group, 9-biphenylcarbazol-4-yl group

[0084] (18): 2-thianthryl group, 10-phenylphenothiazin-3-yl group, 10-phenylphenothiazin-2-yl group, 10-phenylphenoxazin-3-yl group, 10-phenylphenoxazin-2-yl group (19): 1-methylindol-2-yl group, 1-phenylindol-2-yl group, 9-phenylcarbazol-4-yl group

[0085] (20): 4-(2-pyridyl)phenyl group, 4-(3-pyridyl)phenyl group, 4-(4-pyridyl)phenyl group, 3-(2-pyridyl)phenyl group, 3-(3-pyridyl)phenyl group, 3-(4-pyridyl)phenyl group

[0086] (21): 4-(2-phenylimidazol-1-yl)phenyl group, 4-(1-phenylimidazol-2-yl)phenyl group, 4-(2,3,4-triphenylimidazol-1-yl)phenyl group, 4-(1-methyl-4,5-diphenylimidazol-2-yl)phenyl group, 4-(2-methylbenzimidazol-1-yl)phenyl group, 4-(2-phenylbenzimidazol-1-yl)phenyl group, 4-(1-methylbenzimidazol-2-yl)phenyl group, 4-(2-phenylbenzimidazol-1-yl)phenyl group, 3-(2-methylbenzimidazol-1-yl)phenyl group, 3-(2-phenylbenzimidazol-1-yl)phenyl group, 3-(1-methylbenzimidazol-2-yl)phenyl group, 3-(1-phenylbenzimidazol-1-yl)phenyl group

[0087] (22): 4-(3,5-diphenyltriazin-1-yl)phenyl group, 4-(2-thienyl)phenyl group, 4-(2-furanyl)phenyl group, 5-phenylthiophen-2-yl group, 5-phenylfuran-2-yl group, 4-(5-phenylthiophen-2-yl)phenyl group, 4-(5-phenylfuran-2-yl)phenyl group, 3-(5-phenylthiophen-2-yl)phenyl group, 3-(5-phenylfuran-2-yl)phenyl group, 4-(2-benzothienyl)phenyl group, 4-(3-benzothienyl)phenyl group, 3-(2-benzothienyl)phenyl group, 3-(3 -benzothienyl)phenyl group, 4-(2-dibenzothienyl)phenyl group, 4-(4-dibenzothienyl)phenyl group, 3-(2-dibenzothienyl)phenyl group, 3-(4-dibenzothienyl)phenyl group, 4-(2-dibenzofuranyl)phenyl group, 4-(4-dibenzofuranyl)phenyl group, 3-(2-dibenzofuranyl)phenyl group, 3-(4-dibenzofuranyl)phenyl group, 5-phenylpyridin-2-yl group, 4-phenylpyridin-2-yl group, 5-phenylpyridin-3-yl group, 4-(9-carbazolyl)phenyl group, 3-(9-carbazolyl)phenyl group

[0088] (23): 2-dibenzo[g,p]chrysenyl group, 3-dibenzo[g,p]chrysenyl group, 2-(7-phenyl)dibenzo[g,p]chrysenyl group, 3-(7-phenyl)dibenzo[g,p]chrysenyl group

[0089] (24): N,N-diphenylamino group, N,N-bis(4-biphenylyl)-amino group, N,N-bis(3-biphenylyl)-amino group, N-phenyl-4-biphenylamino group, N-phenyl-3-biphenylamino group, N-(4-biphenyl)-4-p-terphenylamino group, N-[4-(carbazol-9-yl)phenyl]-4-biphenylamino group, N 3 -[1,1'-biphenyl]-4-yl-N 1 ,N 1-diphenyl-1,3-benzenediamino group, 4-triphenylamino group, 3-triphenylamino group, 4-(4',4''-diphenyl)triphenylamino group, 3-(4',4''-diphenyl)triphenylamino group, N 1 ,N 1 ,N 3 ,N 3 -Tetraphenyl-1,3-benzenediamino group, 4-(phenylamino)triphenylamino group

[0090] In the fused ring compounds represented by formulae (2A) to (5A), A's are each independently selected from the viewpoint of ease of raw material availability: a phenyl group, a biphenylyl group, a pyridylphenyl group, a terphenylyl group, a naphthyl group, a phenanthryl group, a pyrenyl group, a 9,9-spirobi[9H-fluorenyl] group, a triphenylenyl group, a dibenzothienyl group, a dibenzofuranyl group, a pyridyl group, a pyrimidyl group, or any of these groups substituted with a cyano group, a nitro group, a hydroxyl group, a thiol group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a methyl group, a methoxy group, or a trifluoromethylsulfonyloxy group; a fluorenyl group, a benzofluorenyl group, an anthryl group, a dibenzo[g,p]chrysenyl group, a carbazolyl group, or any of these groups substituted with a cyano group, a nitro group, a hydroxyl group, a thiol group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a methyl group, a methoxy group, or a phenyl group; 4,6-diphenyl-1,3,5-triazin-2-yl group, (4,6-diphenyl-1,3,5-triazin-2-yl)phenyl group, 4,6-bis(4-biphenylyl)-1,3,5-triazin-2-yl group, 4,6-bis(3-biphenylyl)-1,3,5-triazin-2-yl group, cyano group, nitro group, hydroxyl group, thiol group, fluorine atom, chlorine atom, bromine atom, iodine atom, diphenylphosphine oxide, triphenylsilyl group, dihydroxyboryl group (-B(OH)2), 4,4,5,5-tetramethyl-[1,3,2]-dioxaborolanyl group, 5,5-dimethyl-[1,3,2]-dioxaborinane group, methyl group, N,N-diphenylamino group, N,N-bis(4-biphenylyl)amino group, N3 -[1,1'-biphenyl]-4-yl-N 1 ,N 1 -diphenyl-1,3-benzenediamino group, N-phenyl-3-biphenylylamino group, 4-triphenylamino group, 3-triphenylamino group, 4-(4',4''-diphenyl)triphenylamino group, 3-(4',4''-diphenyl)triphenylamino group, N 1 ,N 1 ,N 3 ,N 3 -tetraphenyl-1,3-benzenediamino group or 4-(phenylamino)triphenylamino group is preferred.

[0091] <Preferred specific examples of materials for photoelectric conversion elements for imaging devices> Preferred specific examples of the material for a photoelectric conversion element for an imaging element represented by formula (1) are shown below, but the material is not limited to these.

[0092] Tables B-1 to B-7 show compounds (N-1) to (N-275) that have the skeleton and substitution positions (3Aa) to (4Cd) shown in Tables A-1 to A-3, and the substituent A at the substitution position is a group shown in Tables B-1 to B-7. Here, N represents any symbol from 3Aa to 4Cd. Therefore, for example, in the case of compound (3Aa-3), when N=3Aa, it shows compound (3Aa-3) that has the skeleton of (3Aa) and the substituent A of the skeleton is a Cl atom.

[0093] [Table A-1]

[0094] [Table A-2]

[0095] [Table A-3]

[0096] [Table B-1]

[0097] [Table B-2]

[0098] [Table B-3]

[0099] [Table B-4]

[0100] [Table B-5]

[0101] [Table B-6]

[0102] [Table B-7]

[0103] Preferable specific examples of the material for a photoelectric conversion element for an imaging element represented by formula (1) include the compounds shown below.

[0104] [ka]

[0105] [ka]

[0106] [ka]

[0107]

change

[0108]

change

[0109]

change

[0110]

change

[0111]

change

[0112]

change

[0113]

change

[0114]

change

[0115]

change

[0116]

change

[0117] [ka]

[0118] [ka]

[0119] Preferable specific examples of the material for a photoelectric conversion element for an imaging element represented by formula (1) include the compounds shown below.

[0120] [ka]

[0121] The photoelectric conversion element material for an imaging device according to an embodiment of the present invention can be synthesized by a known method. For example, it can be synthesized by a known method disclosed in JP 2018-193371 A, JP 2019-34939 A, JP 2019-116472 A, JP 2019-34933 A, JP 2020-33332 A, JP 2020-15691 A, JP 2011-6397 A, Japanese Patent No. 4968333 A, US2019 / 0198781 A, and WO 2017 / 109722 A.

[0122] Hereinafter, applications of the material for a photoelectric conversion element for an imaging device according to an embodiment of the present invention will be described.

[0123] <Photoelectric conversion element materials for image sensors, transport materials for photoelectric conversion elements for image sensors> As the material for a photoelectric conversion element for an imaging element according to one embodiment of the present invention, a known material can be used. The material for a photoelectric conversion element for an imaging device can be used, for example, as a transport material for a photoelectric conversion element for an imaging device, or a charge blocking material for a photoelectric conversion element for an imaging device.

[0124] The material for a photoelectric conversion element for an imaging device according to one aspect of the present invention includes a compound containing a skeleton represented by the above formula (1). Further, the transport material for a photoelectric conversion element for an imaging device and the charge blocking material for a photoelectric conversion element for an imaging device according to one aspect of the present invention include a compound containing a skeleton represented by formula (1). The material for a photoelectric conversion element for an imaging device, the transport material for a photoelectric conversion element for an imaging device, and the charge blocking material for a photoelectric conversion element for an imaging device, which include a compound containing a skeleton represented by formula (1), contribute to the production of a material for a photoelectric conversion element for an imaging device that is excellent in dark current and external quantum efficiency characteristics.

[0125] <Regarding molecular weight> The material for a photoelectric conversion element for an imaging device according to one aspect of the present invention or the material for a photoelectric conversion element for an imaging device represented by formula (1) preferably has a molecular weight of 1500 or less, more preferably 1000 or less, from the viewpoint of heat resistance stability during sublimation.

[0126] <Regarding HOMO level> The HOMO level of the material for a photoelectric conversion element for an imaging device according to one aspect of the present invention or the material for a photoelectric conversion element for an imaging device represented by formula (1) is not particularly limited, but from the viewpoint of compatibility with a photoelectric conversion element for an imaging device, the HOMO is preferably 5.0 to 6.5 eV. This HOMO value is a value obtained from measurement by an atmospheric photoelectron yield spectrometer for a vapor-deposited film.

[0127] <Regarding bandgap> The bandgap of the material for a photoelectric conversion element for an imaging device according to one aspect of the present invention or the material for a photoelectric conversion element for an imaging device represented by formula (1) is not particularly limited, but from the viewpoint of compatibility with a photoelectric conversion element for an imaging device, the bandgap is preferably 2.5 to 4.0 eV. This bandgap is a value obtained from the wavelength edge of the absorption spectrum of a vapor-deposited film.

[0128] <Regarding LUMO level> The LUMO level of the material for a photoelectric conversion element for an image sensor according to one embodiment of the present invention or the material for a photoelectric conversion element for an image sensor represented by formula (1) is not particularly limited, but from the viewpoint of compatibility with the photoelectric conversion element for an image sensor, the LUMO is preferably 2.0 to 3.5 eV. Note that this LUMO value is a value obtained from the above-mentioned HOMO value and band gap.

[0129] <Glass transition temperature> The glass transition temperature of the material for a photoelectric conversion element for an imaging element according to one embodiment of the present invention or the material for a photoelectric conversion element for an imaging element represented by formula (1) is not particularly limited, but from the viewpoint of compatibility with the photoelectric conversion element for an imaging element, the glass transition temperature is preferably 100° C. or higher, more preferably 110° C. or higher, and particularly preferably 130° C. or higher. Note that this glass transition temperature is a value obtained by differential scanning calorimetry.

[0130] <About amorphousness> The photoelectric conversion element material for an image sensor according to one embodiment of the present invention or the photoelectric conversion element material for an image sensor represented by formula (1) preferably forms an amorphous layer when vapor-deposited. If the vapor-deposited film is a crystalline layer, the interface with the adjacent layer will not be uniform, which will cause defects in the element. There are no particular limitations on the method for confirming whether the deposited film is an amorphous layer. For example, it can be confirmed by visually checking whether crystallization is present or not, or by XRD measurement of the deposited film to see if no sharp diffraction peaks are observed.

[0131] <About the cove area> One aspect of the present invention is that it has been discovered that compounds having a cove region are promising materials for photoelectric conversion elements for image sensors. In the skeleton represented by formula (1), the presence of the cove region allows X 1 and X 2It is known that a twist occurs in the conjugated system to resolve the steric repulsion between the nuclei. Due to this effect, the photoelectric conversion element material for an image sensor according to one embodiment of the present invention has superior amorphous stability in a vapor-deposited film compared to conventional materials having a planar polycyclic compound as a core. In addition, the photoelectric conversion element material for an image sensor according to one embodiment of the present invention is expected to have the effect of columnar stacking in a manner in which the cores overlap each other due to the twist in the conjugated system. The material for a photoelectric conversion element for an image sensor according to one embodiment of the present invention uses a twisted polycyclic compound having a cove region as the core, which is believed to stabilize the amorphous film formed by vapor deposition and ensure a relatively regular arrangement of the cores within the vapor deposition film, thereby ensuring good charge transport paths, thereby enabling excellent dark current in the photoelectric conversion element for an image sensor. Furthermore, in one embodiment of the present invention, the skeleton can be substituted to impart desired properties, such as adjustment of the HOMO level, an increase in the glass transition temperature, improvement in amorphousness, improvement in charge transport properties, and improvement in blocking properties against reverse charge. For example, when the material for a photoelectric conversion element for an image sensor according to one embodiment of the present invention is used as a hole transport layer in the photoelectric conversion element for an image sensor described below, it is expected to effectively transport holes while simultaneously blocking electrons, which are the reverse charge. Blocking reverse charge can suppress dark current in the photoelectric conversion element for an image sensor.

[0132] It is presumed that these structural characteristics contribute to the function of the material as a material for a photoelectric conversion element for an imaging device, as described below.

[0133] <Photoelectric conversion element for image sensor> A photoelectric conversion element for an imaging device according to one aspect of the present invention includes a material for a photoelectric conversion element for an imaging device according to an embodiment of the present invention. The configuration of the photoelectric conversion element for the imaging device is not particularly limited, but examples thereof include the following configurations (i) to (vi).

[0134] (i): Lower electrode / photoelectric conversion layer / upper electrode (ii): Lower electrode / hole transport layer (electron blocking layer) / photoelectric conversion layer / upper electrode (iii): Lower electrode / photoelectric conversion layer / electron transport layer (hole blocking layer) / upper electrode (iv): Lower electrode / hole transport layer (electron blocking layer) / photoelectric conversion layer / electron transport layer (hole blocking layer) / upper electrode (v): Lower electrode / buffer layer / hole transport layer (electron blocking layer) / photoelectric conversion layer / electron transport layer (hole blocking layer) / upper electrode (vi): Lower electrode / hole transport layer / electron blocking layer / photoelectric conversion layer / hole blocking layer / electron transport layer / upper electrode The buffer layer may be replaced with a layer having a different name or function, as needed, such as a work function adjustment layer.

[0135] Hereinafter, a photoelectric conversion element for an image sensor according to one embodiment of the present invention will be described in more detail using the above configuration (v) as an example, with reference to Fig. 1. Fig. 1 is a schematic cross-sectional view showing an example of the layered configuration of a photoelectric conversion element for an image sensor including a material for a photoelectric conversion element for an image sensor according to one embodiment of the present invention.

[0136] The photoelectric conversion element 100 for an imaging device includes, in this order, a substrate 1, a lower electrode 2, a buffer layer 3, a hole transport layer 4, a photoelectric conversion layer 5, an electron transport layer 6, and an upper electrode 7. Here, the hole transport layer 4 and the electron transport layer 6 may also be called an electron blocking layer and a hole blocking layer, respectively. However, some of these layers may be omitted, or other layers may be added.

[0137] 1, light is incident from below the transparent lower electrode 2. Furthermore, a voltage is applied to the photoelectric conversion element for an imaging device so that, of the charges (holes and electrons) generated in the photoelectric conversion layer 5, the holes move to the lower electrode 2 and the electrons move to the upper electrode 7. In other words, the lower electrode 2 serves as a hole collecting electrode, and the upper electrode 7 serves as an electron collecting electrode.

[0138] [Layer containing material for photoelectric conversion element for image sensor] The photoelectric conversion element for an imaging device contains a material for a photoelectric conversion element for an imaging device in one or more layers selected from the group consisting of a photoelectric conversion layer and a layer between the photoelectric conversion layer and a lower electrode. Thus, in the configuration example shown in Fig. 1, the photoelectric conversion element 100 for an imaging device contains a material for a photoelectric conversion element for an imaging device in at least one layer selected from the group consisting of the photoelectric conversion layer 5 and the hole transport layer 4. In particular, it is preferable that the hole transport layer 4 contains a material for a photoelectric conversion element for an imaging device.

[0139] The material for a photoelectric conversion element for an imaging device may be contained in multiple layers of the photoelectric conversion element for an imaging device, and when an electron blocking layer is provided between the photoelectric conversion layer and the hole transport layer, the electron blocking layer may contain the material for a photoelectric conversion element for an imaging device.

[0140] Hereinafter, the photoelectric conversion element 100 for an imaging element in which the hole transport layer 4 contains a material for a photoelectric conversion element for an imaging element will be described.

[0141] [Board 1] There are no particular limitations on the substrate, and examples include a glass plate, a quartz plate, a plastic plate, etc. In addition, in the case of a configuration in which light is incident from the substrate 1 side, the substrate 1 is transparent to the wavelength of the light.

[0142] [Bottom electrode 2] A lower electrode 2 is provided on a substrate 1 . In the case of a photoelectric conversion element for an imaging device configured so that light passes through the lower electrode and enters the photoelectric conversion layer, the lower electrode is formed of a transparent material that transmits or substantially transmits the light.

[0143] The transparent material used for the lower electrode 2 is not particularly limited, but examples thereof 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.

[0144] In the case of a photoelectric conversion element for an imaging device in which light is incident on the photoelectric conversion layer only from the upper electrode side, the transmittance characteristics of the lower electrode are not important. Therefore, examples of materials that can be used for the lower electrode in this case include iridium, molybdenum, palladium, platinum, etc.

[0145] [Buffer layer 3] A buffer layer 3 is provided between the lower electrode 2 and the hole transport layer 4 described below. The buffer layer 3 also serves to efficiently accept holes from the hole transport layer (electron blocking layer) 4 by adjusting the work function, and is also called a hole injection layer or a work function adjustment layer. Specific examples of conventionally known buffer layers 3 include naphthalene-1,4,5,8-tetracarboxylic dianhydride (NTCDA) and 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (HATCN).

[0146] [Hole transport layer (electron blocking layer) 4] Between the buffer layer 3 and the photoelectric conversion layer 5, a hole transport layer (also called an electron blocking layer) 4 is provided.

[0147] The hole transport layer 4 has a role of transporting holes generated in the photoelectric conversion layer 5 from the photoelectric conversion layer 5 to the lower electrode 2 side, and a role of blocking electrons generated in the photoelectric conversion layer 5 from moving to the lower electrode 2 side. As described above, the hole transport layer 4 preferably contains a material for a photoelectric conversion element for an imaging element.

[0148] The hole transport layer 4 may have a single layer structure made of one or more materials, or a laminate structure made of multiple layers of the same or different compositions. That is, a material having both hole transporting and electron blocking properties may be formed as a single layer hole transport layer, or a laminate structure may be formed by forming a hole transport layer made of a material specialized for hole transporting properties, and then forming an electron blocking layer made of a material specialized for electron blocking properties on the hole transport layer.

[0149] The hole transport layer 4 may further contain a conventionally known hole transport material in addition to the material for a photoelectric conversion element for an imaging element. Examples of the conventionally known hole transport material 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, benzodifuran compounds, benzodithiophene compounds, benzothiophene compounds, naphthobisbenzothiophene compounds, chrysenodithiophene compounds, benzothienobenzothiophene compounds, and indolocarbazole compounds. Among these, fluorene compounds, naphthodithiophene compounds, naphthothienothiophene compounds, benzodifuran compounds, benzothiophene compounds, naphthobisbenzothiophene compounds, chrysenodithiophene compounds, benzothienobenzothiophene compounds, indolocarbazole compounds, and the like are preferred, and fluorene compounds, chrysenodithiophene compounds, benzothienobenzothiophene compounds, and indolocarbazole compounds are particularly preferred.

[0150] Specific examples of conventionally known 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, naphtho[2,3-b]naphtho[2',3':4,5]thieno[2,3-d]thiophene, and benzo[1,2-b:4,5-b']dithiophene. Examples include furan, 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, chryseno[1,2-b:8,7-b']dithiophene, [1]benzothieno[3,2-b][1]benzothiophene, and the following compounds (ic-1) and (ic-2).

[0151] [ka]

[0152] [Photoelectric conversion layer 5] The photoelectric conversion layer 5 is provided between the hole transport layer 4 and the electron transport layer 6 described below. The material of the photoelectric conversion layer 5 may be a material having a photoelectric conversion function.

[0153] The photoelectric conversion layer 5 may have a single layer structure made of one or more materials, or may have a laminate structure made of multiple layers of the same composition or different compositions. Examples of materials used for the photoelectric conversion layer 5, which has a single layer structure made of one type of material, include (1) coumarin and its derivatives, quinacridone and its derivatives, and phthalocyanine and its derivatives. Examples of materials used for the photoelectric conversion layer 5, which has a single layer structure made of two materials, include the above-mentioned combinations of (i) coumarin and its derivatives, quinacridone and its derivatives, and phthalocyanine and its derivatives with (ii) fullerene and its derivatives. The photoelectric conversion layer 5 made of these materials may be formed by depositing a mixture of powders in advance, or by co-depositing the materials in any ratio. Examples of materials used for the photoelectric conversion layer 5, which has a single layer structure made of three materials, include the above-mentioned combinations of (i) coumarin and its derivatives, quinacridone and its derivatives, phthalocyanine and its derivatives, (ii) fullerene and its derivatives, and (iii) hole transport materials. The photoelectric conversion layer 5 made of these materials may be formed by depositing a mixture of powders in advance, or by co-depositing the materials in any ratio.

[0154] (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 derivatives thereof include

[60] fullerene,

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

[60] PCBM). (iii) Preferred compounds and specific examples of the hole transport material are the same as those described above for the hole transport layer 4.

[0155] Furthermore, the material having a photoelectric conversion function is not limited to being contained only in the photoelectric conversion layer 5. For example, the material having a photoelectric conversion function may be contained in a layer adjacent to the photoelectric conversion layer 5 (hole transport layer 4 or electron transport layer 6).

[0156] [Electron transport layer (hole blocking layer) 6] An electron transport layer (also called a hole blocking layer) 6 is provided between the photoelectric conversion layer 5 and an upper electrode 7 described later. The electron transport layer 6 has the role of transporting electrons generated in the photoelectric conversion layer 5 to the upper electrode 7 side and the role of blocking holes generated in the photoelectric conversion layer 5 from moving to the upper electrode 7 side.

[0157] A conventionally known electron transport material can be contained in the electron transport layer 6. Examples of conventionally known electron transport materials include bis(8-hydroxyquinolinato)manganese, tris(8-hydroxyquinolinato)aluminum, tris(2-methyl-8-hydroxyquinolinato)aluminum, BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline), Bphen (4,7-diphenyl-1,10-phenanthroline), BAlq (bis(2-methyl-8-quinolinolato)-4-(phenylphenolato)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.

[0158] The electron transport layer 6 may have a single layer structure made of one or more materials, or may have a laminate structure made of multiple layers of the same or different compositions.

[0159] [Top electrode 7] An upper electrode 7 is provided on the electron transport layer 6 . Examples of materials for the upper electrode 7 include sodium, sodium-potassium alloy, magnesium, lithium, magnesium / copper mixture, silver, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al2O3) mixture, indium, lithium / aluminum mixture, and rare earth metals.

[0160] [How each layer is formed] Each layer except for the lower electrode 2 and upper electrode 7 described above can be formed by forming the material of each layer (together with a material such as a binder resin and a solvent, if necessary) into a thin film by a known method such as vacuum deposition, spin coating, casting, or LB (Langmuir-Blodgett) method. There are no particular limitations on the thickness of each layer formed in this way, and it can be selected appropriately depending on the situation, but it is usually in the range of 5 nm to 5 μm.

[0161] The lower electrode 2 and the upper electrode 7 can be formed by thinning an electrode material by a method such as vapor deposition or sputtering. A pattern may be formed using a mask of a desired shape during vapor deposition or sputtering, or a pattern of a desired shape may be formed by photolithography after forming a thin film by vapor deposition or sputtering.

[0162] The film thickness of the lower electrode 2 and the upper electrode 7 is preferably 1 μm or less, and more preferably 10 nm or more and 200 nm or less.

[0163] The materials constituting the lower electrode 2 and the upper electrode 7 may be interchanged as necessary, or the same material may be used (also called an inverted structure). A specific example of using the same material is when the lower electrode 2 is made of ITO and the upper electrode 7 is formed as an ITO layer by sputtering. In such a structure, light passes through the upper electrode 7 and enters the photoelectric conversion layer 5, forming a photoelectric conversion element for an imaging device. Furthermore, when the materials constituting the lower electrode 2 and the upper electrode 7 are interchanged, the layers may be stacked in the reverse order to the structure (v) above. For example, the structures shown in the following (I) to (IV) may be mentioned. (I): Lower electrode / electron transport layer (hole blocking layer) / photoelectric conversion layer / upper electrode (II): Lower electrode / photoelectric conversion layer / hole transport layer (electron blocking layer) / upper electrode (III): Lower electrode / electron transport layer (hole blocking layer) / photoelectric conversion layer / hole transport layer (electron blocking layer) / upper electrode (IV): Lower electrode / electron transport layer (hole blocking layer) / photoelectric conversion layer / hole transport layer (electron blocking layer) / buffer layer / upper electrode In the above configuration (IV), if the lower electrode and upper electrode are made of a transparent material and a non-transparent material, respectively, as in the configuration (v), the resulting photoelectric conversion element for an imaging device has a configuration in which light passes through the lower electrode and enters the photoelectric conversion layer, but the applied voltage is in the opposite direction to the configuration (v) (also called reverse bias). That is, a voltage is applied so that holes and electrons generated in the photoelectric conversion layer are transported to the upper electrode and lower electrode, respectively. In addition, in the above configuration, the buffer layer serves to reduce damage to the organic film when the upper electrode is formed by sputtering.

[0164] An imaging element including a photoelectric conversion element according to one aspect of the present invention can be used, for example, as an imaging element for a digital camera or a digital video camera, or as an imaging element built into a mobile phone or the like. [Example]

[0165] The present invention will be described in more detail below based on examples, but the present invention should not be construed as being limited to these examples.

[0166] (Element Example A-1: ​​Preparation of a photoelectric conversion element for an imaging element using compound (2C-7)) As shown in Figure 2, a photoelectric conversion element 101 for an imaging device was fabricated having a layered structure consisting of a substrate 1, a lower electrode 2, a hole transport layer 4, a photoelectric conversion layer 5, an electron transport layer 6, and an upper electrode 7, and the dark current of the photoelectric conversion element was evaluated.

[0167] (Preparing substrate 1 and bottom electrode 2) A glass substrate with an indium-tin oxide (ITO) transparent electrode, patterned with a 2 mm wide stripe of ITO (110 nm thick), was prepared as a substrate with a lower electrode on its surface. The substrate was then cleaned with isopropyl alcohol and then subjected to surface treatment using ozone and ultraviolet light.

[0168] (Preparation for vacuum deposition) After cleaning, each layer was deposited on the surface-treated substrate by vacuum deposition using a vacuum deposition method, and each layer was laminated. First, the glass substrate was placed in a vacuum deposition chamber. -5 The pressure was reduced to 100 Pa. Then, each layer was formed in the following order according to the film formation conditions.

[0169] (Preparation of Hole Transport Layer 4) The sublimation-purified compound (2C-7) was deposited at a rate of 0.15 nm / sec to form a 30 nm film, thereby forming a hole transport layer 4. In this configuration, no buffer layer was formed between the lower electrode 2 and the hole transport layer 4.

[0170] (Fabrication of Photoelectric Conversion Layer 5) N,N-dimethylquinacridone was deposited at a rate of 0.30 nm / sec to a thickness of 100 nm to form a photoelectric conversion layer 5.

[0171] (Fabrication of Electron Transport Layer 6) Tris(8-hydroxyquinolinato)aluminum was deposited to a thickness of 30 nm at a rate of 0.15 nm / second to form an electron transport layer 6.

[0172] (Fabrication of upper electrode 7) Finally, a metal mask was placed so as to be perpendicular to the ITO stripes on the substrate, and an upper electrode 7 was formed. The upper electrode was formed by depositing an aluminum film to a thickness of 100 nm. The aluminum film deposition rate was 3 nm / sec.

[0173] As a result, the area of ​​4mm shown in Figure 2 2 The photoelectric conversion element 101 for an imaging device was fabricated. The film thickness of each film was measured using a stylus film thickness measuring instrument (DEKTAK, manufactured by Bruker).

[0174] The device was then sealed in a nitrogen atmosphere glove box with an oxygen and moisture concentration of 1 ppm or less by sealing the glass sealing cap and the film-formed substrate (device) with bisphenol F epoxy resin (manufactured by Nagase ChemteX Corporation).

[0175] The current in a dark place (dark current) was evaluated when a voltage of 2.5 V (absolute value) was applied to the photoelectric conversion element for an image sensor fabricated as described above so that holes were transported to the bottom electrode 2 side and electrons to the top electrode 7 side. The dark current was measured using a Keithley Source Measure Unit 2636B.

[0176] The dark current is a relative value with the result for Comparative Example A-1 set as the reference value (1.0). The measurement results are shown in Table 1.

[0177] (Element Examples A-2 to A-3, Element Comparative Example A-1) In element example A-1, instead of compound (2C-7), compound (2C-25), (3Ja-186), 2,7-diphenyl [1] benzothieno [3,2-b] [1] benzothiophene (DiPh-BTBT) were used, respectively, in order, except that a photoelectric conversion element for an imaging element was prepared in the same manner as element example A-1 and evaluated. The measurement results obtained are shown in Table 1.

[0178] [Table 1]

[0179] As can be seen from Table 1, the material for a photoelectric conversion element for an imaging element according to one embodiment of the present invention can provide a dark current that is two or three orders of magnitude lower than that of the comparative example compound.

[0180] (Element Example B-1: Preparation of a photoelectric conversion element for an imaging element using compound (2C-1)) As shown in Figure 3, a photoelectric conversion element 102 for an imaging device was fabricated, having a layered structure consisting of a substrate 1, a lower electrode 2, an electron transport layer 6, a photoelectric conversion layer 5, a hole transport layer 4, a buffer layer 3, and an upper electrode 7, and the dark current and external quantum efficiency of the photoelectric conversion element were evaluated.

[0181] (Preparing substrate 1 and bottom electrode 2) The substrate 1 and the lower electrode 2 were prepared in the same manner as in element example A-1.

[0182] (Fabrication of Electron Transport Layer 6) The sublimation-purified compound 4,6-bis(3,5-di(pyridin-4-yl)phenyl)-2-methylpyrimidine was deposited at a rate of 0.10 nm / sec to form a film of 10 nm, thereby forming an electron transport layer 6.

[0183] (Fabrication of Photoelectric Conversion Layer 5) A 120 nm film was formed by mixing N,N-dimethylquinacridone and C60 in a mass ratio of 4:1 to produce photoelectric conversion layer 5. The film formation rate was 0.15 nm / second.

[0184] (Preparation of Hole Transport Layer 4) The sublimation-purified compound (2C-1) was formed into a film having a thickness of 10 nm at a rate of 0.10 nm / second to form a hole transport layer 4.

[0185] (Fabrication of buffer layer 3) A buffer layer 3 was prepared by depositing a 10 nm film of the sublimation-purified compound 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (HATCN) at a rate of 0.10 nm / second.

[0186] (Fabrication of upper electrode 7) Finally, a metal mask was placed so as to be perpendicular to the ITO stripes on the substrate, and the upper electrode 7 was formed. The upper electrode was formed by depositing a silver film to a thickness of 80 nm at a silver deposition rate of 0.1 nm / sec.

[0187] As a result, the area of ​​4mm shown in Figure 3 2The photoelectric conversion element 102 for an imaging device was fabricated. The film thickness of each film was measured using a stylus film thickness measuring instrument (DEKTAK, manufactured by Bruker).

[0188] The device was then sealed in a nitrogen atmosphere glove box with an oxygen and moisture concentration of 1 ppm or less by sealing the glass sealing cap and the film-formed substrate (device) with bisphenol F epoxy resin (manufactured by Nagase ChemteX Corporation).

[0189] The photoelectric conversion element for an image sensor fabricated as described above was applied with a voltage of 2.5 V in absolute value in the opposite direction to that of element example A-1, i.e., so that electrons were transported to the lower electrode 2 side and holes were transported to the upper electrode 7 side. The current in the dark (dark current) and external quantum efficiency were evaluated. The dark current was measured using a Keithley Source Measure Unit 2636B. The external quantum efficiency was measured using a solar cell spectral response measurement device (Soma Optical Co., Ltd.). The wavelength of the irradiated light was 560 nm, and the intensity was 50 μW / cm. 2 The results are shown in Table 2.

[0190] The dark current and external quantum efficiency are relative values, with the results for comparative element B-1 taken as reference values ​​of (1.0) and (100), respectively. Table 2 shows the measurement results obtained.

[0191] (Element Examples B-2 to B-19 and Element Comparative Example B-1) In the preparation of the hole transport layer (electron blocking layer) 4 of the element example B-1, instead of compound (2C-1), compound (2C-2), compound (2C-3), compound (2C-7), compound (2C-8), compound (2C-12), compound (2C-13), compound (2C-26), compound (2C-32), compound (2C-61), compound (2C-107), compound (2C-108), compound (3Eb-194), compound (3Ia-91), compound (3Ia-194), compound (3Oa-88), compound (4Ac-192), compound (4Bb-192), compound (5A-0), or 2,7-diphenyl[1]benzothieno[3,2-b] [1] Except for using benzothiophene (DiPh-BTBT), the photoelectric conversion elements for imaging devices of element examples B-2 to B-19 and element comparison example B-1 were fabricated in the same manner as element example B-1, and the dark current and external quantum efficiency were measured in the same manner as element example B-1. The results are shown in Table 2.

[0192] [Table 2]

[0193] As can be seen from Table 2, the material for a photoelectric conversion element for an imaging element according to one embodiment of the present invention can provide higher external quantum efficiency than the comparative example compound.

[0194] Compound (2C-1), compound (2C-2), compound (2C-3), compound (2C-7), compound (2C-8), compound (2C-12), compound (2C-13), compound (2C-25), compound (2C-26), compound (2C-32), compound (2C-61), compound (2C-107), compound (2C-108), compound (3Eb-194), compound (3Ia-91), compound (3Ia-194), compound (3Ib ... Compound (3Ja-186), compound (3Oa-88), compound (4Ac-192), compound (4Bb-192), and compound (5a-0) were synthesized by the methods disclosed in JP 2019-34939 A, JP 2018-193371 A, JP 2020-15691 A, JP 2011-6397 A, JP 2019-34933 A, JP 2020-33332 A, and WO 2017 / 109722. Compound (DiPh-BTBT) was a sublimation grade product from Tokyo Chemical Industry Co., Ltd.

[0195] Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.

[0196] The entire contents of the specifications, claims, drawings and abstracts of Japanese Patent Application No. 2021-098353 filed on June 11, 2021, and Japanese Patent Application No. 2022-001855 filed on January 7, 2022 are hereby incorporated by reference as the disclosure of the specification of the present invention. [Explanation of symbols]

[0197] 1 board 2 Lower electrode 3. Buffer layer 4. Hole transport layer (electron blocking layer) 5 Photoelectric conversion layer 6 Electron transport layer (hole blocking layer) 7 Upper electrode 100 Photoelectric conversion element for imaging device 101 Photoelectric conversion element for image sensor 102 Photoelectric conversion element for image sensor

Claims

1. A photoelectric conversion element for an imaging device, comprising a photoelectric conversion layer, a hole transport layer, and a buffer layer between an upper electrode and a lower electrode, the hole transport layer is provided between the photoelectric conversion layer and the buffer layer and is adjacent to the buffer layer; The hole transport layer contains a material for a photoelectric conversion element for an imaging element, which contains a compound represented by the following formula (2C): the buffer layer is naphthalene-1,4,5,8-tetracarboxylic dianhydride (NTCDA) or 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (HATCN); Photoelectric conversion element for image sensors. 【Chemistry 1】 (In formula (2C), A represents a charge transporting substituent; The charge transporting substituents each independently represent: deuterium atom; fluorine atom, chlorine atom, bromine atom, iodine atom; trifluoromethyl group, pentafluoroethyl group; cyano group; nitro group; hydroxyl groups; thiol groups; a monocyclic, linked, or fused ring aromatic hydrocarbon group having 6 to 30 carbon atoms which may have a substituent; a monocyclic, linked, or fused ring heteroaromatic group having 3 to 36 carbon atoms which may have a substituent; an optionally substituted phosphine oxide group; an optionally substituted silyl group; a boronyl group which may have a saturated hydrocarbon group having 2 to 10 carbon atoms; a linear or branched alkyl group having 1 to 18 carbon atoms; a linear or branched alkoxy group having 1 to 18 carbon atoms; a trifluoromethylsulfonyloxy group; or A group represented by the following formula (6) or (6'): 【Chemistry 2】 (In formulas (6) and (6′), R １００ ~R ３００ are each independently Hydrogen atoms, deuterium atoms; a monocyclic, linked, or fused ring aromatic hydrocarbon group having 6 to 30 carbon atoms which may have a substituent; a monocyclic, linked, or fused ring heteroaromatic group having 3 to 36 carbon atoms which may have a substituent; or represents a linear or branched alkyl group having 1 to 18 carbon atoms; Each L is independently a phenylene group optionally substituted with a methyl group or a phenyl group; a naphthylene group optionally substituted with a methyl group or a phenyl group; a biphenylene group optionally substituted with a methyl group or a phenyl group, or represents a single bond; provided that the group represented by the formula (6) or (6') is a group different from the above-mentioned monocyclic, linked, or fused ring aromatic hydrocarbon group having 6 to 30 carbon atoms which may have a substituent, and the above-mentioned monocyclic, linked, or fused ring heteroaromatic group having 3 to 36 carbon atoms which may have a substituent; n represents 1 or 2; When L is a single bond, n is 1; When L is not a single bond, n is 1 or 2; When n is 2, multiple R １００ or R ２００ may be the same or different.) k represents an integer of 1 to 4; Multiple A's may be the same or different, However, when all of A are groups represented by formula (6) or (6'), k is 2 or less.

2. 2. The photoelectric conversion element for an image pickup device according to claim 1, wherein the hole transport layer, which is a vapor-deposited film of a material for a photoelectric conversion element for an image pickup device, is an amorphous layer.

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