Photoelectric conversion elements, imaging elements, optical sensors, compounds

Abstract

To provide a photoelectric converter excellent also in photoelectric conversion efficiency for visible light; and an imager, a photosensor and a compound.SOLUTION: The photoelectric converter has a conductive film, a photoelectric conversion film and a transparent conductive film in this order, where the photoelectric conversion film contains a compound represented by formula (1).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a photoelectric conversion element, an imaging element, an optical sensor, and a compound. [Background technology]

[0002] In recent years, development of devices having photoelectric conversion films has progressed. For example, Patent Document 1 discloses a compound represented by the following formula as a material to be applied to photoelectric conversion devices.

[0003] [ka] [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2020 / 013246 Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, with the demand for improved performance of image sensors, optical sensors, etc., further improvements in the properties required of photoelectric conversion elements used therein are being demanded. For example, photoelectric conversion elements are being demanded to have excellent photoelectric conversion efficiency for visible light (e.g., wavelengths of 450 nm, 550 nm, and 630 nm). In this specification, excellent photoelectric conversion efficiency for visible light means excellent photoelectric conversion efficiency for all light having wavelengths of 450 nm, 550 nm, and 630 nm, for example.

[0006] The present inventors have investigated photoelectric conversion elements using the compounds disclosed in Patent Document 1 and the like, and have found that the photoelectric conversion efficiency for visible light is poor.

[0007] An object of the present invention is to provide a photoelectric conversion element having excellent photoelectric conversion efficiency for visible light, and also to provide an imaging element, an optical sensor, and a compound. [Means for solving the problem]

[0008] As a result of extensive research into the above-mentioned problems, the present inventors have found that the above-mentioned problems can be solved by using a compound having a specific structure in a photoelectric conversion film, and have thus completed the present invention.

[0009] [1] A photoelectric conversion element having a conductive film, a photoelectric conversion film, and a transparent conductive film in this order, The photoelectric conversion element, wherein the photoelectric conversion film contains a compound represented by formula (1) described below. [2] The photoelectric conversion element according to [1], wherein the compound represented by the formula (1) includes a compound represented by the formula (2) described below. [3] R 7 , R 8 , R E1 and R E2 The photoelectric conversion element according to [2], wherein at least one of the above is a substituent having a positive σp value according to Hammett's rule. [4] The photoelectric conversion element according to any one of [1] to [3], wherein Q is a group represented by formula (Q2) described below. [5] R Q1 The photoelectric conversion element according to any one of [1] to [4], wherein is a trifluoromethyl group or a cyano group. [6] The photoelectric conversion element according to any one of [1] to [5], wherein the absolute value of the HOMO level of the compound represented by the formula (1) is more than 5.30 eV and less than 6.00 eV. [7] the photoelectric conversion film further contains an n-type organic semiconductor, The photoelectric conversion element according to any one of [1] to [6], wherein the photoelectric conversion film has a bulk heterostructure formed by mixing the compound represented by the formula (1) with the n-type organic semiconductor. [8] The photoelectric conversion element according to [7], wherein the n-type organic semiconductor contains a fullerene selected from the group consisting of fullerenes and derivatives thereof. [9] The photoelectric conversion element according to [7] or [8], wherein the photoelectric conversion film further contains a p-type organic semiconductor.

[10] The photoelectric conversion element according to any one of [1] to [9], which has one or more intermediate layers between the conductive film and the transparent conductive film in addition to the photoelectric conversion film.

[11] An imaging device having the photoelectric conversion element according to any one of [1] to

[10] .

[12] An optical sensor having the photoelectric conversion element according to any one of [1] to

[10] .

[13] A compound represented by formula (1) described below.

[14] The compound according to

[13] , which includes a compound represented by formula (2) described below.

[15] R 7 , R 8 , R E1 and R E2 The compound according to

[14] , wherein at least one of the following is a substituent having a positive σp value according to Hammett's rule.

[16] The compound according to any one of

[13] to

[15] , wherein Q is a group represented by formula (Q2) below.

[17] R Q1 is a trifluoromethyl group or a cyano group.

[18] The compound according to any one of

[13] to

[17] , wherein the absolute value of the HOMO level is more than 5.30 eV and less than 6.00 eV. [Effects of the Invention]

[0010] According to the present invention, a photoelectric conversion element having excellent photoelectric conversion efficiency for visible light can be provided. Also, according to the present invention, an imaging element, a photosensor, and a compound can be provided. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 2 is a cross-sectional view showing a configuration example of a photoelectric conversion element. [Figure 2] FIG. 2 is a cross-sectional view showing a configuration example of a photoelectric conversion element. DETAILED DESCRIPTION OF THE INVENTION

[0012] Preferred embodiments of the photoelectric conversion element of the present invention will be described below. In this specification, a numerical range expressed using "to" means a range that includes the numerical values before and after "to" as the lower and upper limits. In this specification, when there are a plurality of substituents, linking groups, etc. (hereinafter also referred to as "substituents, etc.") represented by a specific symbol, or when a plurality of substituents, etc. are simultaneously specified, it means that the respective substituents, etc. may be the same or different from each other. This also applies to the specification of the number of substituents, etc. In this specification, the hydrogen atom may be a protium atom (normal hydrogen atom) or a deuterium atom (for example, a deuterium atom, etc.).

[0013] [Photoelectric conversion element] The photoelectric conversion element of the present invention is a photoelectric conversion element having a conductive film, a photoelectric conversion film, and a transparent conductive film in this order, and the photoelectric conversion film contains a compound represented by formula (1) (hereinafter also referred to as a "specific compound"). A feature of the present invention is that it contains a specific compound. The present inventors speculate that the specific compound has excellent photoelectric conversion efficiency for visible light because it has a group represented by formula (Q1). Hereinafter, superior photoelectric conversion efficiency for visible light is also referred to as "superior effect of the present invention."

[0014] FIG. 1 shows a cross-sectional view of one embodiment of the photoelectric conversion element of the present invention. The photoelectric conversion element 10a shown in Figure 1 has a configuration in which a conductive film (hereinafter also referred to as the "lower electrode") 11 functioning as a lower electrode, an electron blocking film 16A, a photoelectric conversion film 12 containing a specific compound, and a transparent conductive film (hereinafter also referred to as the "upper electrode") 15 functioning as an upper electrode are stacked in this order. Fig. 2 shows an example of the configuration of another photoelectric conversion element. The photoelectric conversion element 10b shown in Fig. 2 has a configuration in which an electron blocking film 16A, a photoelectric conversion film 12, a hole blocking film 16B, and an upper electrode 15 are stacked in this order on a lower electrode 11. Note that the stacking order of the electron blocking film 16A, the photoelectric conversion film 12, and the hole blocking film 16B in Figs. 1 and 2 may be changed as appropriate depending on the application and characteristics.

[0015] In the photoelectric conversion element 10 a or 10 b , it is preferable that light be incident on the photoelectric conversion film 12 through the upper electrode 15 . When the photoelectric conversion element 10a or 10b is used, a voltage can be applied. In this case, the lower electrode 11 and the upper electrode 15 form a pair of electrodes, and a voltage of 1×10 -5 ~1×10 7 From the viewpoint of performance and power consumption, it is preferable to apply a voltage of 1×10 V / cm. -4 ~1×10 7 V / cm is more preferable, and 1×10 -3 ~5×10 6 V / cm is more preferred. 1 and 2, the voltage is preferably applied so that the electron blocking film 16A side serves as the cathode and the photoelectric conversion film 12 side serves as the anode. When the photoelectric conversion element 10a or 10b is used as an optical sensor or incorporated into an imaging element, a voltage can be applied in a similar manner. As will be described in detail later, the photoelectric conversion element 10a or 10b can be suitably used as an imaging element. The configuration of each layer constituting the photoelectric conversion element of the present invention will be described in detail below.

[0016] [Photoelectric conversion film] The photoelectric conversion element has a photoelectric conversion film.

[0017] <Specific compound> The photoelectric conversion film contains a specific compound (a compound represented by formula (1)) as a photoelectric conversion material. The specific compound is represented by the formula (1), R 1 or R 2 and the carbon atom adjacent thereto. In other words, both the cis isomer and the trans isomer distinguished based on the C=C double bond are included in the compound represented by formula (1).

[0018] [ka]

[0019] In formula (1), R 1 ~R 4 R each independently represents a hydrogen atom or a substituent. 3 and R 4 may be bonded to each other to form a ring. a1 and R a2 are each independently -C(R L1 )(R L2 )(R L3 ), an optionally substituted aryl group, or an optionally substituted heteroaryl group. L1 ~R L3 At least two of R independently represent an alkyl group which may have a substituent, an aryl group which may have a substituent, or a heteroaryl group which may have a substituent. L1 ~R L3 R each independently represents an alkyl group which may have a substituent, an aryl group which may have a substituent, a heteroaryl group which may have a substituent, or a hydrogen atom. L1 ~R L3 Any two of these may be bonded to each other to form a ring. Q represents a group represented by formula (Q1).

[0020] R 1 ~R 4 each independently represents a hydrogen atom or a substituent. R 1 ~R 4 Examples of the substituent represented by the formula: include the groups exemplified for the substituent W. R 1 and R 2 is preferably a hydrogen atom. R 3 and R 4 As the group, a substituent is preferable, and an optionally substituted alkyl group, an optionally substituted aryl group, an optionally substituted heteroaryl group, a cyano group, or a halogen atom is more preferable. The alkyl group which may have a substituent preferably has 1 to 10 carbon atoms, and more preferably has 1 to 5 carbon atoms. The optionally substituted aryl group preferably has 6 to 18 carbon atoms, and more preferably 6 to 9 carbon atoms. The optionally substituted heteroaryl group preferably has 3 to 18 carbon atoms, and more preferably 3 to 9 carbon atoms. The halogen atom is preferably a chlorine atom or a fluorine atom. Examples of the substituent that the alkyl group, the aryl group, and the heteroaryl group may have include groups exemplified as the substituent W, and a substituent having a positive σp value in Hammett's rule (specific substituents described later) is preferred, a halogen atom (preferably a chlorine atom or a fluorine atom) or a cyano group is more preferred, and a halogen atom (preferably a chlorine atom or a fluorine atom) is even more preferred. When the alkyl group, aryl group, and heteroaryl group have substituents, the number of the substituents is often 1 to 10, preferably 1 to 4, and more preferably 1 to 3. When the alkyl group, aryl group, and heteroaryl group have a plurality of substituents, the plurality of substituents may be the same or different, and are preferably the same.

[0021] R 3 and R 4may be bonded to each other to form a ring, and preferably are bonded to each other to form a ring. R 3 and R 4 The ring formed by bonding together is preferably an aromatic ring which may have a substituent, more preferably a benzene ring which may have a substituent, a pyridine ring which may have a substituent, or a pyrazine ring which may have a substituent. Examples of the substituent that the ring formed above may have include, for example, R 3 and R 4 Examples of the substituents that the alkyl group, aryl group and heteroaryl group may have are represented by the following formula:

[0022] R a1 and R a2 are each independently -C(R L1 )(R L2 )(R L3 ), an aryl group which may have a substituent, or a heteroaryl group which may have a substituent. R a1 and R a2 As the alkyl group, an aryl group which may have a substituent is preferable, a phenyl group which may have a substituent, a naphthyl group which may have a substituent, or a fluorenyl group which may have a substituent is more preferable, and a phenyl group which may have a substituent is even more preferable. When the aryl group which may have a substituent is a phenyl group which may have a substituent, the phenyl group which may have a substituent is preferably a phenyl group which has a substituent. The substituent of the phenyl group which has a substituent is preferably a specific substituent or an alkyl group, more preferably a cyano group, a chlorine atom or an alkyl group having 1 to 3 carbon atoms. R a1 and R a2 The groups represented by the following formula (I) may be the same or different, and are preferably the same.

[0023] R L1 ~R L3R each independently represents an alkyl group which may have a substituent, an aryl group which may have a substituent, a heteroaryl group which may have a substituent, or a hydrogen atom. L1 ~R L3 At least two of these independently represent an alkyl group which may have a substituent, an aryl group which may have a substituent, or a heteroaryl group which may have a substituent. The alkyl group which may have a substituent may be linear, branched or cyclic. The alkyl group which may have a substituent often has 1 to 10 carbon atoms. Above R L1 ~R L3 Examples of the optionally substituted aryl group and the optionally substituted heteroaryl group represented by the formula (I) include R a1 and R a2 Examples of the aryl group include an aryl group which may have a substituent and a heteroaryl group which may have a substituent, each represented by the following formula:

[0024] R L1 ~R L3 Any two of these may be bonded to each other to form a ring. R L1 ~R L3 The ring formed by bonding any two of the above may be either a monocyclic ring or a polycyclic ring, and may also be either an alicyclic ring or an aromatic ring.

[0025] Q represents a group represented by formula (Q1). In formula (Q1), * represents a bonding position. Q1 R represents a substituent having a positive σp value in Hammett's rule (hereinafter also referred to as a "specific substituent"). Q2 represents an aryl group which may have a substituent or a heteroaryl group which may have a substituent.

[0026] The σp of the specific substituent is greater than 0, and is preferably from 0.06 to 1.00, more preferably from 0.30 to 0.80, and even more preferably from 0.40 to 0.70. The σp in Hammett's rule is the value described in CHEMICAL REVIEWS, 1991, 91, 2, 165-195. The numerical values in parentheses accompanying the specific examples of specific substituents below refer to the σp of the specific substituent. Specifically, the notation "CN(0.66)" indicates that the σp of a cyano group is 0.66.

[0027] Specific substituents include, for example, CN (0.66), halogen atoms (e.g., bromine atom (0.23), chlorine atom (0.23), and fluorine atom (0.06)), CONR t 2(R t represents a hydrogen atom or a substituent), an acyl group (0.50), an arylcarbonyl group (for example, a COC6H5 group (0.43)), an aryl group having a halogen atom (for example, a C6F5 group (0.27)), a formyl group, an acyloxy group, an acylthio group, an alkyloxycarbonyl group, an aryloxycarbonyl group, a dialkylphosphono group, a diarylphosphono group, a dialkylphosphinyl group, a diarylphosphinyl group, a phosphoryl group, an alkylsulfinyl group, an arylsulfinyl group, an acylthio group Examples of the halogen atom include a group, a sulfamoyl group, a thiocarbonyl group, an imino group, an imino group substituted with a nitrogen atom, an alkyl group having two or more halogen atoms (for example, a CF3 group (0.54)), an alkoxy group having two or more halogen atoms, an aryloxy group having two or more halogen atoms, an acylamino group, an alkylamino group having two or more halogen atoms, an alkylthio group having two or more halogen atoms, a heterocyclic group, an azo group, and a selenocyanate group, and these groups may further have a substituent. The specific substituent is preferably a halogen atom (preferably a chlorine atom or a fluorine atom), a cyano group or an alkyl group having two or more halogen atoms, more preferably a trifluoromethyl group or a cyano group.

[0028] The specific substituent preferably does not include a group containing -COO-, a carboxylic acid group, a carboxylate group, a phosphoric acid group, a sulfonic acid group, or a group consisting of a sulfonate group. Examples of the group containing -COO- include -COOR and -CH-COOR. The R represents a substituent.

[0029] R Q2 represents an aryl group which may have a substituent or a heteroaryl group which may have a substituent. R Q2 The optionally substituted aryl group or optionally substituted heteroaryl group represented by the following formula (I) is preferably an optionally substituted aryl group, more preferably an optionally substituted phenyl group. R Q2 The optionally substituted aryl group and optionally substituted heteroaryl group represented by the following formula (I) may be either monocyclic or polycyclic. R Q2 The number of ring members in the optionally substituted aryl group and optionally substituted heteroaryl group represented by the following formula (I) is preferably 5 to 12, and more preferably 5 to 6. Examples of the substituent that the aryl group and heteroaryl group may have include the groups exemplified as the substituent W, and specific substituents are preferred, with a fluorine atom, a chlorine atom or a cyano group being more preferred. When the aryl group and the heteroaryl group have substituents, the number of the substituents is preferably 1 to 5, more preferably 1 to 3, and even more preferably 1 or 2.

[0030] When the specific compound is a compound represented by formula (1) and Q is a group represented by formula (Q1), the specific compound is a compound represented by formula (X1).

[0031] [ka]

[0032] Q is preferably a group represented by formula (Q2).

[0033] [ka]

[0034] In formula (Q2), * represents the bonding position. Q1 represents a substituent with a positive σp value in Hammett's rule. Q3 ~R Q7 each independently represents a hydrogen atom or a substituent.

[0035] R Q1 is R in equation (Q1) Q1 The preferred embodiments are also the same as those described above. R Q3 ~R Q7 each independently represents a hydrogen atom or a substituent. R Q3 ~R Q7 Examples of the substituent represented by the formula (I) include the groups exemplified as the substituent W, and an alkyl group or a specific substituent is preferred, with a fluorine atom, a chlorine atom or a cyano group being more preferred. R Q3 , R Q4 , R Q6 and R Q7 is preferably a hydrogen atom, and R Q5 is preferably a hydrogen atom or a substituent.

[0036] The compound represented by formula (1) preferably includes a compound represented by formula (2).

[0037] [ka]

[0038] In formula (2), R 5 ~R 8 R each independently represents a hydrogen atom or a substituent. 7 and R 8 may be bonded to each other to form a ring. a3 and R a4 are each independently -C(R L4)(R L5 )(R L6 ), an optionally substituted aryl group, or an optionally substituted heteroaryl group. L4 ~R L6 R each independently represents an alkyl group which may have a substituent, an aryl group which may have a substituent, a heteroaryl group which may have a substituent, or a hydrogen atom. L4 ~R L6 At least two of R independently represent an alkyl group which may have a substituent, an aryl group which may have a substituent, or a heteroaryl group which may have a substituent. L4 ~R L6 Any two of E may be bonded to each other to form a ring. 1 is a nitrogen atom or -CR E1 = R E1 represents a hydrogen atom or a substituent. 2 is a nitrogen atom or -CR E2 = R E2 represents a hydrogen atom or a substituent, and Q represents a group represented by formula (Q1).

[0039] R 5 and R 6 is the above R 1 and the above R 2 and the preferred embodiments are also the same. R 7 and R 8 The substituent represented by the formula (I) is the same as the above R 3 and the above R 4 Examples of substituents include those represented by the formula: R 7 and R 8 The substituent represented by the formula (I) is preferably a specific substituent, and is preferably a halogen atom (preferably a chlorine atom or a fluorine atom), a cyano group or an alkyl group having two or more halogen atoms, more preferably a chlorine atom.

[0040] R 7 and R 8 may be bonded to each other to form a ring. R 7 and R 8Examples of the ring formed by bonding together include R 3 and R 4 are bonded to each other to form a ring.

[0041] R a3 and R a4 is the above R a1 and the above R a2 and the preferred embodiments are also the same. Q is a group represented by the above formula (Q1).

[0042] E 1 is a nitrogen atom or -CR E1 = R E1 represents a hydrogen atom or a substituent. 2 is a nitrogen atom or -CR E2 = R E2 represents a hydrogen atom or a substituent. E 1 As for -CR E1 = is preferred. E 2 As for -CR E2 = is preferred. R E1 and R E2 Examples of the substituent represented by the formula (I) include specific substituents, and a cyano group or a halogen atom (preferably a chlorine atom or a fluorine atom) is preferred, with a chlorine atom being more preferred.

[0043] -Substituent W- Examples of the substituent W include a halogen atom (such as a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom), an alkyl group, an alkenyl group (including a cycloalkenyl group and a bicycloalkenyl group), an alkynyl group, an aryl group, a heterocyclic group (including a heteroaryl group), a cyano group, a hydroxy group, a nitro group, an alkoxy group, an aryloxy group, a silyloxy group, a heterocyclic oxy group, an acyloxy group, a carbamoyloxy group, an alkoxycarbonyloxy group, an aryloxycarbonyloxy group, an amino group (including an anilino group), an ammonio group, an acylamino group, an aminocarbonylamino group, an alkoxycarbonylamino group, an aryloxycarbonylamino group, a sulfamoylamino group, an aryl Examples of the alkyl or arylsulfonylamino group, mercapto group, alkylthio group, arylthio group, heterocyclic thio group, sulfamoyl group, alkyl or arylsulfinyl group, alkyl or arylsulfonyl group, acyl group, aryloxycarbonyl group, alkoxycarbonyl group, carbamoyl group, aryl or heterocyclic azo group, imido group, phosphino group, phosphinyl group, phosphinyloxy group, phosphinylamino group, phosphono group, silyl group, hydrazino group, ureido group, boronic acid group (-B(OH)2), sulfo group, carboxylic acid group, phosphoric acid group, phosphonyl group, phosphoryl group, monosulfuric acid ester group, monophosphate ester group, phosphonic acid group, phosphinic acid group, and boric acid group. The substituent W may be further substituted with a substituent W. For example, when the substituent W is an alkyl group, it may be further substituted with a halogen atom to form an alkyl group having a halogen atom. The substituent W also includes, for example, a specific substituent. Examples of the substituent W include the substituent W described in paragraph

[0023] of JP-A-2007-234651, the contents of which are incorporated herein by reference.

[0044] The alkyl group, aryl group, and heteroaryl group that the specific compound may have may be an alkyl group X, an aryl group X, and a heteroaryl group X, respectively.

[0045] -Alkyl group X- The alkyl group X preferably has 1 to 15 carbon atoms, more preferably 1 to 10 carbon atoms, and even more preferably 1 to 6 carbon atoms. The alkyl group X may be linear, branched, or cyclic. Examples of the alkyl group X include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, a t-butyl group, an n-hexyl group, and a cyclopentyl group. The alkyl group X may be, for example, a cycloalkyl group, a bicycloalkyl group, or a tricycloalkyl group, and may have these cyclic structures as partial structures. Examples of the substituent that the alkyl group X may have include the substituent W, and an aryl group (preferably having 6 to 18 carbon atoms, more preferably having 6 carbon atoms), a heteroaryl group (preferably having 5 to 18 carbon atoms, more preferably having 5 to 6 carbon atoms) or a halogen atom (preferably a fluorine atom or a chlorine atom) is preferred.

[0046] -aryl group X- The aryl group X preferably has 6 to 18 carbon atoms. The aryl group X may be either monocyclic or polycyclic. The aryl group X is preferably, for example, a phenyl group, a naphthyl group, an anthryl group or a fluorenyl group, and more preferably a phenyl group. Examples of the substituent that the aryl group X may have include the substituent W, and an optionally substituted alkyl group (preferably having 1 to 10 carbon atoms) is preferred, and a methyl group or an i-propyl group is more preferred.

[0047] The heteroatom contained in the heteroaryl group X is preferably a sulfur atom, an oxygen atom or a nitrogen atom. The heteroaryl group X may be either monocyclic or polycyclic. The heteroaryl group X preferably has 3 to 18 carbon atoms, and more preferably has 3 to 5 carbon atoms. The heteroaryl group X preferably has 1 to 10 heteroatoms, more preferably 1 to 4 heteroatoms, and even more preferably 1 or 2 heteroatoms. The heteroaryl group X preferably has 3 to 8 ring members, more preferably 5 to 7 ring members, and even more preferably 5 or 6 ring members. Examples of the heteroaryl group X include a furyl group, a pyridyl group, a quinolyl group, an isoquinolyl group, an acridinyl group, a phenanthridinyl group, a pteridinyl group, a pyrazinyl group, a quinoxalinyl group, a pyrimidinyl group, a quinazolyl group, a pyridazinyl group, a cinnolinyl group, a phthalazinyl group, a triazinyl group, an oxazolyl group, a benzoxazolyl group, a thiazolyl group, a benzothiazolyl group, an imidazolyl group, a benzimidazolyl group, a pyrazolyl group, an indazolyl group, an isoxazolyl group, a benzisoxazolyl group, an isothiazolyl group, a benzisothiazolyl group, an oxadiazolyl group, a thiadiazolyl group, a triazolyl group, a tetrazolyl group, a benzofuryl group, a thienyl group, a benzothienyl group, a dibenzofuryl group, a dibenzothienyl group, a pyrrolyl group, an indolyl group, an imidazopyridinyl group, and a carbazolyl group. The substituent that the heteroaryl group X may have is, for example, the substituent W, and is preferably an alkyl group or an aryl group.

[0048] As preferred embodiments of the specific compound, Embodiments A and B are preferred. Aspect A: The number of specific substituents (substituents whose σp in Hammett's rule is a positive value) that the compound represented by formula (1) or the compound represented by formula (2) has is preferably 1 to 10, more preferably 2 to 6, and even more preferably 3 to 5. Aspect B: The total value of σp of specific substituents (substituents whose σp is a positive value according to Hammett's rule) possessed by the compound represented by formula (1) or the compound represented by formula (2) is preferably 0.8 to 2.5, more preferably 1.0 to 2.2, and even more preferably 1.1 to 2.0.

[0049] Examples of specific compounds are shown below. When the specific compounds exemplified below are applied to formula (1), R 1 or R 2The specific compounds exemplified below include all geometric isomers that can be distinguished based on the C=C double bond formed by the carbon atom to which the carbon atom is bonded and the carbon atom adjacent thereto. In other words, both the cis isomer and the trans isomer distinguished based on the C=C double bond are included in the specific compounds exemplified below.

[0050] [ka]

[0051] [ka]

[0052] The absolute value of the HOMO level of the specific compound is often more than 5.00 eV and less than 6.20 eV, preferably more than 5.30 eV and less than 6.00 eV, and more preferably more than 5.40 eV and less than 5.80 eV. The absolute value of the HOMO level can be determined by quantum chemical calculations using the commercially available Gaussian09 program, and is the value obtained when the ground state is structurally optimized using B3LYP / 6-31G(d). The absolute value of the HOMO level can be adjusted, for example, by changing the chemical structure of a specific compound (e.g., the number and type of specific substituents).

[0053] The molecular weight of the specific compound is not particularly limited, but is preferably 400 to 1200. If the molecular weight is 1200 or less, the deposition temperature does not become high and decomposition of the compound does not occur easily. If the molecular weight is 400 or more, the glass transition point of the deposited film does not become low and the heat resistance of the photoelectric conversion element is improved.

[0054] From the viewpoints of stability when used as a p-type organic semiconductor and matching of the energy level with an n-type organic semiconductor, the absolute value of the ionization potential of the specific compound in a single film is preferably 5.0 to 6.4 eV, more preferably 5.5 to 6.2 eV, and even more preferably 5.7 to 6.0 eV.

[0055] The maximum absorption wavelength of the specific compound is preferably in the range of 500 to 600 nm, more preferably in the range of 520 to 580 nm, and even more preferably in the range of 530 to 560 nm. The maximum absorption wavelength is a value measured in a solution state (solvent: chloroform) after adjusting the absorption spectrum of the specific compound to a concentration such that the absorbance is 0.5 to 1.0. However, if the specific compound is not soluble in chloroform, the specific compound is vapor-deposited into a film state, and the value measured using the specific compound is regarded as the maximum absorption wavelength of the specific compound.

[0056] The particular compound may be purified if necessary. The method for purifying the specific compound is not particularly limited, but sublimation purification is preferred. The purity of the specific compound after sublimation purification (for example, purity measured by HPLC or GC) is not particularly limited, but is preferably 95% or more, more preferably 98% or more, and even more preferably 99% or more.

[0057] Before the specific compound is purified by sublimation, the specific compound may be purified by other methods. For example, the specific compound is preferably subjected to purification using silica gel column chromatography, purification using GPC (Gel Permeation Chromatography), reslurry washing, reprecipitation purification, purification using an adsorbent such as activated carbon, and recrystallization purification. The purity of the specific compound before sublimation purification (for example, purity measured by HPLC or GC) is not particularly limited, but is preferably 95% or more, more preferably 98% or more, and even more preferably 99% or more. The solvent used for recrystallization purification (recrystallization solvent) is not particularly limited, and examples thereof include methanol, ethanol, isopropanol, butanol, toluene, xylene, anisole, 1,2-dimethoxybenzene, tetralin, chlorobenzene, dichlorobenzene, hexane, heptane, octane, acetonitrile, benzonitrile, acetic acid, chloroform, dichloromethane, ethyl acetate, butyl acetate, tetrahydrofuran, 4-methyltetrahydropyran, and cyclopentyl methyl ether. The recrystallization solvent may be a mixture of multiple solvents.

[0058] The amount of residual solvent contained in the crude product containing the specific compound to be subjected to sublimation purification is not particularly limited, but the amount of residual solvent is preferably 10 mol % or less, more preferably 5 mol % or less, and even more preferably 2 mol % or less, relative to the total molar amount of the specific compound in the crude product.

[0059] The amount of impurities, including elements not constituting the specific compound (e.g., Li, Na, K, Mg, Ca, Al, Si, P, Sn, transition metal elements, etc.), contained in the crude material containing the specific compound to be subjected to sublimation purification is not particularly limited, but is preferably 1000 ppm by mass or less, more preferably 100 ppm by mass or less, and even more preferably 10 ppm by mass or less, relative to the total mass of the crude material. The above elements can be measured by ICP (inductively coupled plasma) emission spectrometry.

[0060] The specific compound can be synthesized by a known method. In order to improve the purity of the specific compound, the purity (e.g., purity measured by HPLC or GC) of the raw materials used in the synthesis of the specific compound, including intermediates, is not particularly limited, but is preferably 97% or more, more preferably 98% or more, and even more preferably 99% or more. When the purity of commercially available raw materials and synthetic intermediates is low, they may be purified by known methods and used.

[0061] The specific compounds may be used alone or in combination of two or more. The content of the specific compound in the photoelectric conversion film (=(film thickness of the specific compound in terms of a single layer) / (film thickness of the photoelectric conversion film)×100) is preferably 15 to 75% by volume, more preferably 20 to 60% by volume, and even more preferably 25 to 50% by volume.

[0062] The specific compound is particularly useful as a material for a photoelectric conversion film used in an image pickup device, a photosensor or a photovoltaic cell. Note that the specific compound often functions as a p-type organic semiconductor in the photoelectric conversion film. Further, the specific compound can also be used as a coloring material, a liquid crystal material, an organic semiconductor material, a charge transport material, a pharmaceutical material and a fluorescent diagnostic agent material.

[0063] <n-type organic semiconductor> Preferably, the photoelectric conversion film contains an n-type organic semiconductor in addition to the above specific compound. The n-type organic semiconductor is a compound different from the above specific compound. The n-type organic semiconductor is an acceptor-type organic semiconductor material (compound), which refers to an organic compound having a property of easily accepting electrons. That is, the n-type organic semiconductor refers to the organic compound having a larger electron affinity when two organic compounds are used in contact with each other. That is, as the acceptor-type organic semiconductor, any organic compound can be used as long as it is an organic compound having electron accepting properties.

[0064] Examples of n-type organic semiconductors include fullerenes selected from the group consisting of fullerenes and derivatives thereof, fused aromatic carbon ring compounds (e.g., naphthalene derivatives, anthracene derivatives, phenanthrene derivatives, tetracene derivatives, pyrene derivatives, perylene derivatives, and fluoranthene derivatives); 5- to 7-membered heterocyclic compounds having at least one selected from the group consisting of a nitrogen atom, an oxygen atom, and a sulfur atom (e.g., pyridine, pyrazine, pyrimidine, pyridazine, triazine, quinoline, quinoxaline, quinazoline, phthalazine, cinnoline, isoquinoline, pteridine, acridine, phenazine, phenanthroline, tetrazole, pyridine ... pyridine, pyridine, pyridine, pyridine, pyridine, pyridine, pyridine, pyridine, pyridine, pyridine, pyridine, pyridine, pyridine, pyridine, pyridine, pyridine, pyridine, azoles, imidazoles, thiazoles, etc.); polyarylene compounds; fluorene compounds; cyclopentadiene compounds; silyl compounds; 1,4,5,8-naphthalenetetracarboxylic anhydride; 1,4,5,8-naphthalenetetracarboxylic anhydride imide derivatives and oxadiazole derivatives; anthraquinodimethane derivatives; diphenylquinone derivatives; bathocuproine, bathophenanthroline, and derivatives thereof; triazole compounds; distyrylarylene derivatives; metal complexes having a nitrogen-containing heterocyclic compound as a ligand; silole compounds; and the compounds described in paragraphs

[0056] to

[0057] of JP 2006-100767 A.

[0065] As the n-type organic semiconductor (compound), fullerenes selected from the group consisting of fullerene and derivatives thereof are preferred. Examples of fullerenes include fullerene C60, fullerene C70, fullerene C76, fullerene C78, fullerene C80, fullerene C82, fullerene C84, fullerene C90, fullerene C96, fullerene C240, fullerene C540, and mixed fullerenes. Examples of fullerene derivatives include compounds in which a substituent is added to the above-mentioned fullerene. The substituent is preferably an alkyl group, an aryl group, or a heterocyclic group. Preferred fullerene derivatives are compounds described in JP-A-2007-123707.

[0066] As the n-type organic semiconductor, an organic dye may be used. Examples of organic dyes include cyanine dyes, styryl dyes, hemicyanine dyes, merocyanine dyes (including zeromethine merocyanine (simple merocyanine)), rhodacyanine dyes, allopolar dyes, oxonol dyes, hemioxonol dyes, squarium dyes, croconium dyes, azamethine dyes, coumarin dyes, arylidene dyes, anthraquinone dyes, triphenylmethane dyes, azo dyes, azomethine dyes, metallocene dyes, fluorenone dyes, fulgide dyes, perylene dyes, phenazine dyes, phenothiazine dyes, quinone dyes, diphenylmethane dyes, polyene dyes, acridine dyes, acridinone dyes, diphenylamine dyes, quinophthalone dyes, phenoxazine dyes, phthaloperylene dyes, dioxane dyes, porphyrin dyes, chlorophyll dyes, phthalocyanine dyes, subphthalocyanine dyes, and metal complex dyes.

[0067] The molecular weight of the n-type organic semiconductor is preferably 200 to 1,200, more preferably 200 to 900.

[0068] The maximum absorption wavelength of the n-type organic semiconductor is preferably in the range of 400 to 650 nm, more preferably in the range of 420 to 550 nm, and even more preferably in the range of 450 to 500 nm. The maximum absorption wavelength can be measured using the method for measuring the maximum absorption wavelength of the specific compound.

[0069] The photoelectric conversion film preferably has a bulk heterostructure formed by mixing a specific compound with an n-type organic semiconductor. The bulk heterostructure is a layer in the photoelectric conversion film in which the specific compound and the n-type organic semiconductor are mixed and dispersed. The photoelectric conversion film having a bulk heterostructure can be formed by either a wet method or a dry method. The bulk heterostructure is described in detail in paragraphs

[0013] to

[0014] of JP 2005-303266 A.

[0070] The difference in electron affinity between the specific compound and the n-type organic semiconductor is preferably 0.1 eV or more.

[0071] The n-type organic semiconductor may be used alone or in combination of two or more kinds. In terms of the responsivity of the photoelectric conversion element, the content of the specific compound with respect to the total content of the specific compound and the n-type organic semiconductor (film thickness in terms of a single layer of the specific compound / (film thickness in terms of a single layer of the specific compound + film thickness in terms of a single layer of the n-type organic semiconductor) × 100) is preferably 20 to 80% by volume, more preferably 40 to 80% by volume. Further, when the photoelectric conversion film further contains a p-type organic semiconductor described later, the content of the specific compound (film thickness in terms of a single layer of the specific compound / (film thickness in terms of a single layer of the specific compound + film thickness in terms of a single layer of the n-type organic semiconductor + film thickness in terms of a single layer of the p-type organic semiconductor) × 100) is preferably 15 to 75% by volume, more preferably 35 to 75% by volume. The photoelectric conversion film is preferably substantially composed of the specific compound, the n-type organic semiconductor, and, if necessary, the p-type organic semiconductor. "Substantially" means that the total content of the specific compound, the n-type organic semiconductor, and the p-type organic semiconductor is 95% by mass or more with respect to the total mass of the photoelectric conversion film. The upper limit is often 100% by mass or less.

[0072] <p-type organic semiconductor> The photoelectric conversion film preferably contains a p-type organic semiconductor in addition to the above specific compound. The photoelectric conversion film also preferably contains the specific compound, the n-type organic semiconductor, and the p-type organic semiconductor. The p-type organic semiconductor is a compound different from the above specific compound. The p-type organic semiconductor is a donor-type organic semiconductor material (compound), which refers to an organic compound having a property of easily donating electrons. That is, the p-type organic semiconductor refers to the organic compound with a smaller ionization potential when two organic compounds are brought into contact and used.

[0073] Examples of p-type organic semiconductors include triarylamine compounds (e.g., N,N'-bis(3-methylphenyl)-(1,1'-biphenyl)-4,4'-diamine (TPD), 4,4'-bis[N-(naphthyl)-N-phenyl-amino]biphenyl (α-NPD), compounds described in paragraphs

[0128] to

[0148] of JP-A No. 2011-228614, compounds described in paragraphs

[0052] to

[0063] of JP-A No. 2011-176259, compounds described in paragraphs

[0052] to

[0063] of JP-A No. 2011-225544, compounds described in paragraphs

[0119] to

[0158] of JP-A No. 2015-1 compounds described in paragraphs

[0044] to

[0051] of JP-A No. 53910 and the compounds described in paragraphs

[0086] to

[0090] of JP-A No. 2012-94660), pyrazoline compounds, styrylamine compounds, hydrazone compounds, polysilane compounds, thiophene compounds (for example, thienothiophene derivatives, dibenzothiophene derivatives, benzodithiophene derivatives, dithienothiophene derivatives, [1]benzothieno[3,2-b]thiophene (BTBT) derivatives, thieno[3,2-f:4,5-f']bis[1]benzothiophene (TBBT) derivatives, JP-A No. 2012-94660, etc.), compounds described in paragraphs

[0031] to

[0036] of WO 2018-014474; compounds described in paragraphs

[0043] to

[0045] of WO 2016-194630; compounds described in paragraphs

[0025] to

[0037] and

[0099] to

[0109] of WO 2017-159684; compounds described in paragraphs

[0029] to

[0034] of JP 2017-076766 A; compounds described in paragraphs

[0015] to

[0025] of WO 2018-207722; compounds described in paragraphs

[0045] to

[0053] of JP 2019-054228; the compounds described in paragraphs

[0045] to

[0055] of JP-A-2019-081416, the compounds described in paragraphs

[0063] to

[0089] of WO2019-081416, the compounds described in paragraphs

[0033] to

[0036] of JP-A-2019-80052, the compounds described in paragraphs

[0044] to

[0054] of WO2019-054125, the compounds described in paragraphs

[0041] to

[0046] of WO2019-093188, the compounds described in paragraphs

[0034] to

[0037] of JP-A-2019-050398, the compounds described in paragraphs

[0033] to

[0036] of JP-A-2018-206878,The compound of paragraph

[0038] of JP 2018-190755 A, the compound of paragraphs

[0019] to

[0021] of JP 2018-026559 A, the compound of paragraphs

[0031] to

[0056] of JP 2018-170487 A, the compound of paragraphs

[0036] to

[0041] of JP 2018-078270 A, the compound of paragraphs

[0055] to

[0082] of JP 2018-11 The compounds of paragraphs

[0041] to

[0050] of JP 3425 A, the compounds of paragraphs

[0044] to

[0048] of JP 2018-85430 A, the compounds of paragraphs

[0041] to

[0045] of JP 2018-056546 A, the compounds of paragraphs

[0042] to

[0049] of JP 2018-046267 A, the compounds of paragraphs

[0031] to

[0036] of JP 2018-014474 A, WO2018-01646 Examples of the compounds include compounds described in paragraphs

[0036] to

[0046] of Japanese Patent Application Laid-Open No. 2020-010024, paragraphs

[0045] to

[0048] , cyanine compounds, oxonol compounds, polyamine compounds, indole compounds, pyrrole compounds, pyrazole compounds, polyarylene compounds, fused aromatic carbocyclic compounds (for example, naphthalene derivatives, anthracene derivatives, phenanthrene derivatives, tetracene derivatives, pentacene derivatives, pyrene derivatives, perylene derivatives, and fluoranthene derivatives), porphyrin compounds, phthalocyanine compounds, triazole compounds, oxadiazole compounds, imidazole compounds, polyarylalkane compounds, pyrazolone compounds, amino-substituted chalcone compounds, oxazole compounds, fluorenone compounds, silazane compounds, and metal complexes having a nitrogen-containing heterocyclic compound as a ligand. Examples of p-type organic semiconductors include compounds with a smaller ionization potential than n-type organic semiconductors, and if this condition is met, the organic dyes exemplified as n-type organic semiconductors can be used. Examples of p-type organic semiconductors include the following compounds:

[0074] [ka]

[0075] [ka]

[0076] [ka]

[0077] [ka]

[0078] The difference in ionization potential between the specific compound and the p-type organic semiconductor is preferably 0.1 eV or more.

[0079] When the photoelectric conversion film contains a p-type organic semiconductor, the content of the p-type organic semiconductor in the photoelectric conversion film (=film thickness of p-type organic semiconductor in single layer equivalent / film thickness of photoelectric conversion film × 100) is preferably 15 to 75% by volume, more preferably 20 to 60% by volume, and even more preferably 25 to 50% by volume. The p-type organic semiconductor may be used alone or in combination of two or more.

[0080] The photoelectric conversion film containing the specific compound is a non-luminescent film and has characteristics different from those of an organic electroluminescent device (OLED: Organic Light Emitting Diode). A non-luminescent film means a film with a luminescence quantum efficiency of 1% or less, preferably 0.5% or less, and more preferably 0.1% or less. The lower limit is often 0% or more.

[0081] The maximum absorption wavelength of the photoelectric conversion film is preferably in the range of 500 to 600 nm, more preferably in the range of 520 to 580 nm, and even more preferably in the range of 530 to 565 nm. The maximum absorption wavelength can be measured using the method for measuring the maximum absorption wavelength of the specific compound.

[0082] <Film forming method> The photoelectric conversion film may be formed by, for example, a dry film formation method. Examples of dry film formation methods include vapor deposition (particularly vacuum deposition), sputtering, physical vapor deposition such as ion plating and molecular beam epitaxy (MBE), and chemical vapor deposition (CVD) such as plasma polymerization, with vacuum deposition being preferred. When forming a photoelectric conversion film by vacuum deposition, the manufacturing conditions, such as the degree of vacuum and deposition temperature, can be set according to conventional methods.

[0083] The thickness of the photoelectric conversion film is preferably from 10 to 1000 nm, more preferably from 50 to 800 nm, still more preferably from 50 to 500 nm, and particularly preferably from 50 to 300 nm.

[0084] [electrode] The photoelectric conversion element preferably has an electrode. The electrodes (upper electrode (transparent conductive film) 15 and lower electrode (conductive film) 11) are made of a conductive material. Examples of the conductive material include metals, alloys, metal oxides, electrically conductive compounds, and mixtures thereof. Since light is incident through the upper electrode 15, the upper electrode 15 is preferably transparent to the light to be detected. Examples of materials constituting the upper electrode 15 include conductive metal oxides such as antimony- or fluorine-doped tin oxide (ATO: Antimony Tin Oxide, FTO: Fluorine-doped Tin Oxide), tin oxide, zinc oxide, indium oxide, indium tin oxide (ITO: Indium Tin Oxide), and indium zinc oxide (IZO); thin metal films such as gold, silver, chromium, and nickel; mixtures or laminates of these metals and conductive metal oxides; and organic conductive materials such as polyaniline, polythiophene, and polypyrrole. From the viewpoints of high conductivity and transparency, conductive metal oxides are preferred.

[0085] Generally, when a conductive film is made thinner than a certain range, the resistance value often increases sharply. In a solid-state imaging device incorporating a photoelectric conversion element according to this embodiment, the sheet resistance may be 100 to 10,000 Ω / □, and there is a large degree of freedom in the range of the film thickness that can be reduced. Furthermore, the thinner the upper electrode (transparent conductive film) 15, the less light it absorbs, and generally the higher the light transmittance. An increase in light transmittance is preferable because it increases the light absorption in the photoelectric conversion film and enhances the photoelectric conversion capacity. Considering the suppression of leakage current, the increase in the resistance value of the thin film, and the increase in transmittance that accompany a thinner film, the thickness of the upper electrode 15 is preferably 5 to 100 nm, and more preferably 5 to 20 nm.

[0086] Depending on the application, the lower electrode 11 may be made transparent or non-transparent and light-reflective. Examples of materials constituting the lower electrode 11 include conductive metal oxides such as antimony- or fluorine-doped tin oxide (ATO, FTO), tin oxide, zinc oxide, indium oxide, indium tin oxide (ITO), and indium zinc oxide (IZO); metals such as gold, silver, chromium, nickel, titanium, tungsten, and aluminum; conductive compounds such as oxides or nitrides of these metals (e.g., titanium nitride (TiN)); mixtures or laminates of these metals and conductive metal oxides; and organic conductive materials such as polyaniline, polythiophene, and polypyrrole.

[0087] The method for forming the electrode can be appropriately selected depending on the electrode material, and specific examples include wet methods such as printing and coating, physical methods such as vacuum deposition, sputtering, and ion plating, and chemical methods such as CVD and plasma CVD. When the electrode material is ITO, examples of methods include an electron beam method, a sputtering method, a resistance heating vapor deposition method, a chemical reaction method (such as a sol-gel method), and coating of a dispersion of indium tin oxide.

[0088] [Charge blocking film: electron blocking film, hole blocking film] The photoelectric conversion element preferably has one or more intermediate layers in addition to the photoelectric conversion film between the conductive film and the transparent conductive film. The intermediate layer may be, for example, a charge-blocking film. If the photoelectric conversion element has this film, the resulting photoelectric conversion element will have better properties (such as photoelectric conversion efficiency and responsiveness). Examples of the charge-blocking film include an electron-blocking film and a hole-blocking film.

[0089] <Electron blocking film> The electron blocking film is a donor organic semiconductor material (compound), and the above-mentioned p-type organic semiconductor can be used. Furthermore, polymeric materials can also be used as the electron blocking film. Examples of polymeric materials include polymers of phenylene vinylene, fluorene, carbazole, indole, pyrene, pyrrole, picoline, thiophene, acetylene, and diacetylene, as well as derivatives thereof.

[0090] The electron blocking film may be made up of multiple films. The electron blocking film may be composed of an inorganic material. Generally, inorganic materials have a higher dielectric constant than organic materials, so when an inorganic material is used for the electron blocking film, a higher voltage is applied to the photoelectric conversion film, resulting in higher photoelectric conversion efficiency. Examples of inorganic materials that can be used for the electron blocking film include calcium oxide, chromium oxide, chromium copper oxide, manganese oxide, cobalt oxide, nickel oxide, copper oxide, gallium copper oxide, strontium copper oxide, niobium oxide, molybdenum oxide, indium copper oxide, indium silver oxide, and iridium oxide.

[0091] <Hole-blocking film> The hole-blocking film is an acceptor organic semiconductor material (compound), and the above-mentioned n-type organic semiconductor can be used. The hole blocking film may be made up of multiple films.

[0092] Examples of methods for producing a charge-blocking film include dry film formation and wet film formation. Examples of dry film formation include vapor deposition and sputtering. Vapor deposition may be either physical vapor deposition (PVD) or chemical vapor deposition (CVD), with physical vapor deposition such as vacuum deposition being preferred. Wet film formation includes inkjet printing, spray printing, nozzle printing, spin coating, dip coating, casting, die coating, roll coating, bar coating, and gravure coating, with inkjet printing being preferred from the standpoint of high-precision patterning.

[0093] The thickness of each of the charge blocking films (electron blocking film and hole blocking film) is preferably 3 to 200 nm, more preferably 5 to 100 nm, and even more preferably 5 to 30 nm.

[0094] <Substrate> The photoelectric conversion element may further include a substrate. Examples of the substrate include a semiconductor substrate, a glass substrate, and a plastic substrate. The position of the substrate is not particularly limited, but typically, a conductive film, a photoelectric conversion film, and a transparent conductive film are laminated in this order on the substrate.

[0095] <Sealing layer> The photoelectric conversion element may further include a sealing layer. The performance of photoelectric conversion materials can be significantly degraded in the presence of degrading factors such as water molecules, etc. Therefore, the degradation can be prevented by covering and sealing the entire photoelectric conversion film with a sealing layer made of ceramics such as dense metal oxide, metal nitride, or metal nitride oxide, or diamond-like carbon (DLC), which does not allow water molecules to penetrate. The sealing layer is described, for example, in paragraphs

[0210] to

[0215] of JP-A No. 2011-082508, the contents of which are incorporated herein by reference.

[0096] [Image sensor] Photoelectric conversion elements are used, for example, as imaging elements. An imaging device is an element that converts the optical information of an image into an electrical signal, and is usually composed of multiple photoelectric conversion elements arranged in a matrix on the same plane, with each photoelectric conversion element (pixel) converting the optical signal into an electrical signal and outputting the electrical signal pixel by pixel from the imaging device. For this reason, each pixel is composed of one or more photoelectric conversion elements and one or more transistors.

[0097] [Optical sensor] Other uses of the photoelectric conversion element include, for example, photocells and optical sensors, and the photoelectric conversion element of the present invention is preferably used as an optical sensor. As an optical sensor, the photoelectric conversion element may be used alone, or may be used as a line sensor in which the photoelectric conversion elements are arranged linearly, or as a two-dimensional sensor in which the photoelectric conversion elements are arranged on a plane.

[0098] [Compound] The present invention also includes inventions relating to specific compounds. [Example]

[0099] The present invention will be described in more detail below based on examples. The materials, amounts used, ratios, treatment details, and treatment procedures shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the examples shown below. The absolute values of the HOMO levels of the compounds are determined by quantum chemical calculations using the commercially available Gaussian09 program, and are values obtained when the ground state is structurally optimized using B3LYP / 6-31G(d).

[0100] [Compounds used in photoelectric conversion films] [Synthesis of Compound (D-1)] Compound (D-1) was synthesized according to the following scheme.

[0101] [ka]

[0102] To a mixture of 4,5-dichloro-1,2-phenylenediamine (75.0 g, 424 mmol) and diethyl oxalate (92.9 g, 635 mmol), 4 M hydrochloric acid (169 mL) was added dropwise. The mixture was stirred at 80°C for 5 hours, then allowed to cool to room temperature, and water (200 mL) was added dropwise. The resulting precipitate was filtered, and the resulting crude product (filtered residue) was washed with water and then methanol. The target product (filtered residue) was dried under reduced pressure to obtain intermediate (D-1-2) (97.5 g, 100% yield).

[0103] To a mixture of (chloromethylene)dimethyliminium chloride (162 g, 1.27 mol) and N, dehydrated N-dimethylformamide (300 mL) was added the intermediate (D-1-2) (97.5 g, 422 mmol) obtained above. The mixture was stirred at 65 °C for 3 hours and then allowed to cool to room temperature. The resulting reaction solution was added in small portions to water (1.5 L) cooled to 0 °C. The resulting precipitate was filtered, and the resulting crude product (filtered product) was washed with water and then methanol. The target product (filtered product) was dried under reduced pressure to obtain intermediate (D-1-3) (96.1 g, yield 85%).

[0104] 2,6-Xylidine was purified by the following method. To a mixture of 2,6-xylidine (300 g, 2.48 mol) and isopropanol (300 mL), 30% hydrochloric acid (288 mL, 2.73 mol) was added dropwise, and the resulting reaction mixture was stirred under reflux for 1 hour. The mixture was cooled to 2°C, and the resulting crystals were filtered. The resulting crystals were washed with isopropanol and then hexane to obtain 2,6-xylidine hydrochloride (350 g, 90% yield). Subsequently, 50% aqueous sodium hydroxide solution (199 g, 2.48 mol) was added dropwise to a mixture of 2,6-xylidine hydrochloride (300 g, 1.90 mol) and water (600 mL), and the resulting reaction mixture was stirred at room temperature (25°C) for 1 hour. The resulting mixture was transferred to a separatory funnel, washed with hexane (150 mL), and the aqueous phase was removed. The resulting organic phase was concentrated under reduced pressure to obtain 2,6-xylidine (200 g, 87%).

[0105] To a mixture of intermediate (D-1-3) (22.6 g, 84.4 mmol), the 2,6-dimethylaniline (24.6 g, 203 mmol) obtained above, and tetrahydrofuran (226 mL), a 38% by mass solution of sodium hexamethyldisilazide (NaHMDS) in tetrahydrofuran (1.9 mol / L) (200 mL, 380 mmol) was added dropwise. The mixture was stirred at 60°C for 1 hour and then allowed to cool to room temperature. Water (113 mL) was added dropwise to the mixture. 25% by mass brine (100 mL) was then added to the mixture, and the organic phase of the mixture was extracted. The organic phase was dried over magnesium sulfate and then filtered. The filtrate was concentrated under reduced pressure. The crude product obtained after the vacuum concentration was dispersed in hexane and washed. The washed crude product was filtered and dried under reduced pressure to obtain intermediate (D-1-4) (25.8 g, yield 70%).

[0106] p-Toluenesulfonic acid monohydrate (26.1 g, 137 mmol), acetic anhydride (46 mL), and intermediate (D-1-4) (20.0 g, 45.7 mmol) were mixed, and the resulting reaction solution was stirred at 130 °C for 3 hours. The reaction solution was allowed to cool to room temperature and then added dropwise to a mixture of 50 w / v% aqueous sodium hydroxide (230 mL) and ice (690 g), and the resulting reaction mixture was stirred for 30 minutes. Acetic acid was added to the reaction mixture to adjust the pH to 8 at 25 °C, and the reaction mixture was further stirred for 20 minutes. The resulting precipitate was filtered, and the resulting crude product (filtered product) was washed sequentially with water and methanol. The washed crude product was reprecipitated using dichloromethane / methanol. The target product obtained by reprecipitation was collected by filtration and dried under reduced pressure to obtain intermediate (D-1-5) (15.0 g, 71% yield).

[0107] To a mixture of (chloromethylene)dimethyliminium chloride (8.32 g, 65.0 mmol) and acetonitrile (130 mL), intermediate (D-1-5) (10.0 g, 21.7 mmol) was added, and the resulting reaction solution was stirred at room temperature (25 °C) for 1 hour. The reaction solution was allowed to cool to room temperature and then added dropwise to a mixture of 1 mol / L aqueous sodium hydroxide (150 mL) and ice (150 g), and the resulting mixture was stirred for 30 minutes. Acetic acid was added to the reaction mixture to adjust the pH to 7-8 at 25 °C, and the reaction mixture was further stirred for 10 minutes. The precipitate formed in the mixture was filtered, and the resulting crude product (filtered product) was washed with water and then methanol. The washed crude product was purified by silica gel column chromatography (eluent: toluene). The resulting target product was further purified by repeating the reprecipitation procedure twice using dichloromethane / methanol. The target product obtained by reprecipitation was filtered off, and the target product (filtered product) was dried under reduced pressure to obtain intermediate (D-1-6) (6.89 g, yield 65%).

[0108] 3-Cyano-1-phenyl-5-pyrazolone (D-1-7) was synthesized according to the method described in JP-A-2008-088198.

[0109] Intermediate (D-1-6) (3.00 g, 6.13 mmol), 3-cyano-1-phenyl-5-pyrazolone (D-1-7) (1.48 g, 7.97 mmol), and acetic anhydride (45 mL) were mixed. The mixture was stirred at 110 °C for 3 hours, then cooled in an ice bath, and the resulting precipitate was filtered. The resulting crude product (filtered residue) was purified by silica gel column chromatography (eluent: toluene: ethyl acetate = 95:5). The resulting target product was further purified by reprecipitation using dichloromethane / methanol twice. The purified target product was dried under reduced pressure at 200 °C for 6 hours to obtain compound (D-1) (3.00 g, 75% yield, HPLC purity of 99.7% or higher).

[0110] The resulting compound (D-1) was identified by NMR (Nuclear Magnetic Resonance), and the results are as follows: Two types of isomers were confirmed by NMR. 1 H-NMR (CDCl3, 400 MHz) δ = 2.21 (12H, d), 6.10 (minor isomer, 0.17H, d), 6.71 (major isomer, 0.83H, d), 6.81 (minor isomer, 0.17H, d), 6.86 (major isomer, 0.83H, d), 7.16 (1H, t), 7.33 (2H, t), 7.39-7.67 (6H, m), 7.75-7.81 (2H, m), 8.07 (2H, d).

[0111] The compounds (D-2) to (D-9) and the compounds (R-1) to (R-6) were each synthesized with reference to the synthesis method for the compound (D-1) described above.

[0112] Each compound is shown below. The compounds (D-1) to (D-9) are specific compounds, and the compounds (R-1) to (R-6) are comparative compounds.

[0113] [ka]

[0114] [ka]

[0115] [n-type organic semiconductor] C60: Fullerene (C 60 )

[0116] [p-type organic semiconductor]

[0117] [ka]

[0118] 〔evaluation〕 [Fabrication of photoelectric conversion element] The obtained compound was used to fabricate a photoelectric conversion element having the configuration shown in Fig. 1. The photoelectric conversion element here comprises a lower electrode 11, an electron blocking film 16A, a photoelectric conversion film 12, and an upper electrode 15. Specifically, amorphous ITO was deposited on a glass substrate by sputtering to form a lower electrode 11 (film thickness: 30 nm), and the following compound (EB-1) was further deposited on the lower electrode 11 by vacuum thermal evaporation to form an electron blocking film 16A (film thickness: 30 nm). Furthermore, with the substrate temperature controlled at 25°C, compound (D-1) and an n-type organic semiconductor (fullerene (C 60 )) were co-deposited by vacuum deposition to form a film of 120 nm in monolayer equivalent. This resulted in the formation of a photoelectric conversion film 12 having a bulk heterostructure of 240 nm (360 nm when a p-type organic semiconductor was also used). The film formation rate of the photoelectric conversion film 12 was 1.0 Å / sec. Furthermore, amorphous ITO was deposited on the photoelectric conversion film 12 by sputtering to form an upper electrode 15 (transparent conductive film) (film thickness: 10 nm). An SiO film was formed as a sealing layer on the upper electrode 15 by vacuum deposition, and then an aluminum oxide (Al2O3) layer was formed thereon by ALCVD (Atomic Layer Chemical Vapor Deposition), thereby producing the photoelectric conversion element of Example 1. Using the above-described production procedure as a reference, each photoelectric conversion element of the examples and comparative examples was produced using compounds (D-2) to (D-9) or compounds (R-1) to (R-6). Hereinafter, the photoelectric conversion element obtained by the above-described photoelectric conversion element production procedure will also be referred to as "element A."

[0119] [ka]

[0120] [Evaluation of photoelectric conversion efficiency (external quantum efficiency)] The operation of each of the obtained photoelectric conversion elements (element (A)) was confirmed. 5A voltage was applied to achieve an electric field strength of 1000 V / cm. Light was then irradiated from the upper electrode (transparent conductive film) side, and IPCE (incident photon-to-current conversion efficiency) measurements were performed to extract the external quantum efficiency at wavelengths of 450 nm, 550 nm, and 630 nm. The external quantum efficiency was measured using an Optel constant energy quantum efficiency measurement device. The irradiated light intensity was 50 μW / cm. 2 The photoelectric conversion efficiency at each wavelength when compound (D-1) was used was normalized to 1. It was confirmed that the photoelectric conversion devices prepared using compounds (D-1) to (D-9) each exhibited a photoelectric conversion efficiency of 50% or more at all wavelengths, and had sufficient external quantum efficiency as photoelectric conversion devices. Furthermore, the devices using compounds (R-1) to (R-6) had low absorptance at a wavelength of 630 nm and external quantum efficiency of less than 50%, so only values at wavelengths of 450 nm and 550 nm were extracted. In practical terms, a grade of D or higher is preferred, with A being most preferred. (Evaluation criteria) A: 0.95 or higher B: 0.9 or more, less than 0.95 C: 0.85 or more, less than 0.9 D: 0.8 or more, less than 0.85 E: Less than 0.8

[0121] Table 1 shows the evaluation results. The "*" in Table 1 indicates that the absorption at a wavelength of 630 nm was small and the external quantum efficiency was less than 50%.

[0122] [Table 1]

[0123] From the results shown in the above table, it was confirmed that the photoelectric conversion element of the present invention has excellent photoelectric conversion efficiency for visible light (photoelectric conversion efficiency for all light with wavelengths of 450 nm, 550 nm, and 630 nm). On the other hand, it was confirmed that the photoelectric conversion element of the comparative example has poor photoelectric conversion efficiency for at least one of the above wavelengths, and is unable to achieve a balance in photoelectric conversion efficiency for the above three wavelengths. In particular, it was found that the photoelectric conversion element of the comparative example has extremely low absorption at a wavelength of 630 nm, making it unsuitable as a photoelectric conversion element for visible light. It has been confirmed that the effects of the present invention are more excellent when the absolute value of the HOMO level of the specific compound is more than 5.30 eV and less than 6.00 eV (comparison between Examples 1 and 9, etc.). It was confirmed that the effects of the present invention are more excellent when the photoelectric conversion film contains an n-type organic semiconductor and a p-type organic semiconductor (comparison between Examples 1 and 12, etc.). [Explanation of symbols]

[0124] 10a, 10b Photoelectric conversion element 11 Conductive film (bottom electrode) 12 Photoelectric conversion film 15 Transparent conductive film (upper electrode) 16A Electron Blocking Film 16B Hole-blocking film

Claims

1. A photoelectric conversion element having a conductive film, a photoelectric conversion film, and a transparent conductive film in this order, The photoelectric conversion element, wherein the photoelectric conversion film contains a compound represented by formula (1): 【Chemical 1】 In formula (1), R １ and R 2 represent a hydrogen atom. ４ R each independently represents a hydrogen atom, an alkyl group which may have a halogen atom, a cyano group, or a halogen atom. ３ and R ４ may be bonded to each other to form an alkyl group which may have a halogen atom, a cyano group, or an aromatic ring which may have a halogen atom. ａ１ and R ａ２ each independently represents an alkyl group, an aryl group which may have a halogen atom or a cyano group, or a heteroaryl group which may have an alkyl group, a halogen atom or a cyano group. Q represents a group represented by formula (Q1). In formula (Q1), * represents a bonding position. Ｑ１ represents a cyano group, a halogen atom, an alkyl group having two or more halogen atoms, an acyl group, or an arylcarbonyl group. Ｑ２ represents a cyano group, an aryl group which may have a halogen atom or an alkyl group, or a heteroaryl group which may have a cyano group, a halogen atom or an alkyl group.

2. The photoelectric conversion element according to claim 1 , wherein the compound represented by formula (1) includes a compound represented by formula (2): 【Chemistry 2】 In formula (2), R ５ and R 6 represent a hydrogen atom. ８ R each independently represents a hydrogen atom, an alkyl group which may have a halogen atom, a cyano group, or a halogen atom. ７ and R ８ may be bonded to each other to form an alkyl group which may have a halogen atom, a cyano group, or an aromatic ring which may have a halogen atom. ａ３ and R ａ４ each independently represents an alkyl group, an aryl group which may have a halogen atom or a cyano group, or a heteroaryl group which may have an alkyl group, a halogen atom or a cyano group. １ is a nitrogen atom or -CR Ｅ１ = represents. R Ｅ１ represents a hydrogen atom, an alkyl group which may have a halogen atom, a cyano group, or a halogen atom. ２ is a nitrogen atom or -CR Ｅ２ = represents. R Ｅ２ represents a hydrogen atom, an alkyl group which may have a halogen atom, a cyano group, or a halogen atom. Q represents a group represented by the formula (Q1).

3. R ７ , R ８ , R Ｅ１ and R Ｅ２ 3. The photoelectric conversion element according to claim 2, wherein at least one of the above is a substituent having a positive σp value according to Hammett's rule.

4. 4. The photoelectric conversion element according to claim 1, wherein Q is a group represented by formula (Q2): 【Chemistry 3】 In formula (Q2), * represents a bonding position. Ｑ１ represents a cyano group, a halogen atom, an alkyl group having two or more halogen atoms, an acyl group, or an arylcarbonyl group. Ｑ３ ~R Ｑ７ each independently represents a hydrogen atom, a cyano group, a halogen atom or an alkyl group.

5. R Ｑ１ The photoelectric conversion element according to any one of claims 1 to 4, wherein is a trifluoromethyl group or a cyano group.

6. 6. The photoelectric conversion element according to claim 1, wherein the absolute value of the HOMO level of the compound represented by formula (1) is greater than 5.30 eV and less than 6.00 eV.

7. the photoelectric conversion film further contains an n-type organic semiconductor, The photoelectric conversion element according to any one of claims 1 to 6, wherein the photoelectric conversion film has a bulk heterostructure formed by mixing the compound represented by formula (1) and the n-type organic semiconductor.

8. The photoelectric conversion element according to claim 7 , wherein the n-type organic semiconductor comprises a fullerene selected from the group consisting of fullerenes and derivatives thereof.

9. The photoelectric conversion element according to claim 7 , wherein the photoelectric conversion film further contains a p-type organic semiconductor.

10. 10. The photoelectric conversion element according to claim 1, further comprising one or more intermediate layers in addition to the photoelectric conversion film between the conductive film and the transparent conductive film.

11. An imaging device comprising the photoelectric conversion element according to any one of claims 1 to 10.

12. An optical sensor comprising the photoelectric conversion element according to any one of claims 1 to 10.

13. A compound represented by formula (1): 【Chemistry 4】 In formula (1), R １ and R 2 represent a hydrogen atom. ４ R each independently represents a hydrogen atom, an alkyl group which may have a halogen atom, a cyano group, or a halogen atom. ３ and R ４ may be bonded to each other to form an alkyl group which may have a halogen atom, a cyano group, or an aromatic ring which may have a halogen atom. ａ１ and R ａ２ each independently represents an alkyl group, an aryl group which may have a halogen atom or a cyano group, or a heteroaryl group which may have an alkyl group, a halogen atom or a cyano group. Q represents a group represented by formula (Q1). In formula (Q1), * represents a bonding position. Ｑ１ represents a cyano group, a halogen atom, an alkyl group having two or more halogen atoms, an acyl group, or an arylcarbonyl group. Ｑ２ represents a cyano group, an aryl group which may have a halogen atom or an alkyl group, or a heteroaryl group which may have a cyano group, a halogen atom or an alkyl group.

14. The compound according to claim 13, which is a compound represented by formula (2): 【Chemistry 5】 In formula (2), R ５ and R 6 represent a hydrogen atom. ８ R each independently represents a hydrogen atom, an alkyl group which may have a halogen atom, a cyano group, or a halogen atom. ７ and R ８ may be bonded to each other to form an alkyl group which may have a halogen atom, a cyano group, or an aromatic ring which may have a halogen atom. ａ３ and R ａ４ each independently represents an alkyl group, an aryl group which may have a halogen atom or a cyano group, or a heteroaryl group which may have an alkyl group, a halogen atom or a cyano group. １ is a nitrogen atom or -CR Ｅ１ = represents. R Ｅ１ represents a hydrogen atom, an alkyl group which may have a halogen atom, a cyano group, or a halogen atom. ２ is a nitrogen atom or -CR Ｅ２ = represents. R Ｅ２ represents a hydrogen atom, an alkyl group which may have a halogen atom, a cyano group, or a halogen atom. Q represents a group represented by the formula (Q1).

15. R ７ , R ８ , R Ｅ１ and R Ｅ２ The compound according to claim 14, wherein at least one of the following is a substituent having a positive σp value according to Hammett's rule.

16. The compound according to any one of claims 13 to 15, wherein Q is a group represented by formula (Q2): 【Chemistry 6】 In formula (Q2), * represents a bonding position. Ｑ１ represents a cyano group, a halogen atom, an alkyl group having two or more halogen atoms, an acyl group, or an arylcarbonyl group. Ｑ３ ~R Ｑ７ each independently represents a hydrogen atom, a cyano group, a halogen atom or an alkyl group.

17. R Ｑ１ The compound according to any one of claims 13 to 16, wherein is a trifluoromethyl group or a cyano group.

18. The compound according to any one of claims 13 to 17, wherein the absolute value of the HOMO level is greater than 5.30 eV and less than 6.00 eV.

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