Photoelectric conversion element, imaging element, optical sensor, method for manufacturing imaging element, and compound

Abstract

The present invention addresses the problem of providing a photoelectric conversion element having a response speed that is not highly dependent on electric field strength. The photoelectric conversion element according to the present invention includes a conductive film, a photoelectric conversion film, and a transparent conductive film in this order, wherein the photoelectric conversion film contains a compound represented by formula (1) or formula (2).

Description

Photoelectric conversion element, imaging element, optical sensor, method for producing imaging element, compound

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

[0002] In recent years, development of elements including a photoelectric conversion film (for example, imaging elements) has been progressing. For example, Patent Document 1 discloses a photoelectric conversion element including a predetermined dithienochrysene derivative.

[0003] International Publication No. 2019 / 054125

[0004] Along with the demand for performance improvement of imaging elements, optical sensors, and the like, photoelectric conversion elements exhibiting excellent various properties are required. Examples of properties required for a photoelectric conversion element include that the response speed of the photoelectric conversion element is less likely to change even when the electric field intensity is changed, that is, the dependence of the response speed on electric field intensity is small. Under such a requirement, the present inventors produced and studied a photoelectric conversion element including the compound disclosed in Patent Document 1, and found that the dependence of response speed on electric field intensity does not satisfy a desired level, and there is room for improvement.

[0005] Accordingly, an object of the present invention is to provide a photoelectric conversion element having small dependence of response speed on electric field intensity. Another object of the present invention is to provide an imaging element, an optical sensor, a method for producing an imaging element, and a compound related to the above photoelectric conversion element.

[0006] As a result of intensive studies to solve the above problems, the present inventors have found that the problems can be solved by the following configuration.

[0007] [1] A photoelectric conversion element having a conductive film, a photoelectric conversion film, and a transparent conductive film in this order, wherein the photoelectric conversion film contains a compound represented by formula (1) or formula (2) described later. [2] X ３ is -CR １ =, and X ５ is -CR ２The photoelectric conversion element according to [1], wherein １ , X ２ , and X ４ is a sulfur atom, the photoelectric conversion element according to any one of [1] to [4]. [6] The photoelectric conversion element according to any one of [1] to [5], wherein the photoelectric conversion film further contains a dye. [7] The photoelectric conversion element according to any one of [1] to [6], wherein the photoelectric conversion film further contains an n-type organic semiconductor. [8] The photoelectric conversion element according to [7], wherein the n-type organic semiconductor includes a fullerene selected from the group consisting of fullerenes and derivatives thereof. [9] The photoelectric conversion element according to any one of [1] to [8], which has one or more intermediate layers in addition to the photoelectric conversion film between the conductive film and the transparent conductive film.

[10] An imaging element comprising the photoelectric conversion element according to any one of [1] to [9].

[11] An optical sensor comprising the photoelectric conversion element according to any one of [1] to [9].

[12] A method for producing an imaging element, comprising a step of producing the photoelectric conversion element according to any one of [1] to [9].

[13] A compound represented by formula (1) or formula (2) described below.

[14] X ３ is -CR １ =, and X ５ is -CR ２ =, the compound according to

[13] .

[15] The compound according to

[13] or

[14] , wherein n is 0.

[16] The compound according to any one of

[13] to

[15] , wherein each Z is independently a group represented by any one of the above formula (5) to formula (9).

[17] X １ , X ２ , and X ４ is a sulfur atom, the compound according to any one of

[13] to

[16] .

[0008] According to the present invention, a photoelectric conversion element with low dependence of response speed on electric field strength can be provided. Furthermore, according to the present invention, an image sensor, a light sensor, a method for manufacturing the image sensor, and a compound related to the above-mentioned photoelectric conversion element can also be provided.

[0009] This is a schematic cross-sectional diagram showing one example of the configuration of a photoelectric conversion element.

[0010] The present invention will be described in detail below. The following descriptions of constituent elements may be based on typical embodiments of the present invention, but the present invention is not limited to such embodiments.

[0011] In this specification, a numerical range represented by "~" means a range that includes the numbers written before and after "~" as the lower and upper limits, respectively.

[0012] In this specification, a hydrogen atom may be either a light hydrogen atom (a normal hydrogen atom) or a deuterium atom (for example, a double hydrogen atom). In this specification, when there are multiple substituents and linking groups, etc. (hereinafter also referred to as "substituents, etc.") indicated by a specific symbol, or when multiple substituents, etc. are specified simultaneously, it means that each substituent, etc. may be identical or different from the others. The same applies to the specification of the number of substituents, etc.

[0013] In this specification, unless otherwise specified, "substituent" refers to the group exemplified by the substituent W below.

[0014] (Substituent W) The substituent W in this specification is described below. Substituent W is, for example, a halogen atom (e.g., fluorine atom, chlorine atom, bromine atom, and iodine atom), an alkyl group (including cycloalkyl groups, bicycloalkyl groups, and tricycloalkyl groups), an alkenyl group (including cycloalkenyl groups and bicycloalkenyl groups), an alkynyl group, an aryl group, a heterocyclic group (heteroaryl groups and aliphatic heterocyclic groups), a cyano group, a nitro group, an alkoxy group, an aryloxy group, a silyl group, a silyloxy group, a heterocyclic oxy group, an acyloxy group, a carbamoyloxy group, an alkoxycarbonyloxy group, an aryloxycarbonyl Examples include oxy groups, primary, secondary, or tertiary amino groups (including anilino groups), alkylthio groups, arylthio groups, heterocyclic thio groups, alkyl or arylsulfinyl groups, alkyl or arylsulfonyl groups, acyl groups, aryloxycarbonyl groups, alkoxycarbonyl groups, aryl or heterocyclic azo groups, imide groups, phosphino groups, phosphinyl groups, phosphinyloxy groups, phosphinylamino groups, phosphono groups, carboxyl groups, phosphoric acid groups, sulfonic acid groups, hydroxyl groups, thiol groups, acylamino groups, carbamoyl groups, ureido groups, and boronic acid groups. Each of the above groups may, if possible, have further substituents (for example, one or more of the above groups). For example, an alkyl group which may have substituents is also included as one form of substituent W. If substituent W has carbon atoms, the number of carbon atoms in substituent W is, for example, 1 to 20. The number of atoms other than hydrogen atoms in substituent W is, for example, 1 to 30. The specific compounds described later may have substituents such as carboxyl group, carboxyl group salt, phosphate group, phosphate group salt, sulfonic acid group, sulfonic acid group salt, hydroxyl group, thiol group, acylamino group, carbamoyl group, ureido group, or boronic acid group (-B(OH)). ２ ) and / or the absence of a primary amino group is also preferable.

[0015] In this specification, examples of halogen atoms include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms.

[0016] In this specification, unless otherwise specified, aliphatic hydrocarbon groups may be linear, branched, or cyclic. Examples of aliphatic hydrocarbon groups include alkyl groups, alkenyl groups, and alkynyl groups. In this specification, unless otherwise specified, the number of carbon atoms in an alkyl group is preferably 1 to 20, more preferably 1 to 10, and even more preferably 1 to 6. Unless otherwise specified, alkyl groups may be linear, branched, or cyclic. Examples of alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-hexyl, cyclopropyl, and cyclopentyl groups. Cyclic alkyl groups may be cycloalkyl groups, bicycloalkyl groups, and tricycloalkyl groups, and alkyl groups may have these ring structures as partial structures. In alkyl groups that may have substituents, examples of substituents that the alkyl group may have include the group exemplified by substituent W. Among these, aryl groups (preferably having 6 to 18 carbon atoms, more preferably 6 carbon atoms), heteroaryl groups (preferably having 5 to 18 carbon atoms, more preferably 5 to 6 carbon atoms), or halogen atoms (preferably fluorine atoms or chlorine atoms) are preferred.

[0017] In this specification, unless otherwise specified, the alkyl portion of the alkoxy group and alkylthio group is preferably the alkyl group described above. In an alkoxy group which may have substituents, examples of substituents that the alkoxy group may have are the same as examples of substituents in an alkyl group which may have substituents. In an alkylthio group which may have substituents, examples of substituents that the alkylthio group may have are the same as examples of substituents in an alkyl group which may have substituents.

[0018] In this specification, unless otherwise specified, the alkenyl group may be linear, branched, or cyclic. The number of carbon atoms in the alkenyl group is preferably 2 to 20. In an alkenyl group which may have substituents, examples of substituents that the alkenyl group may have are the same as examples of substituents in an alkyl group which may have substituents. In this specification, unless otherwise specified, the alkynyl group may be linear, branched, or cyclic. The number of carbon atoms in the alkynyl group is preferably 2 to 20. In an alkynyl group which may have substituents, examples of substituents that the alkynyl group may have are the same as examples of substituents in an alkyl group which may have substituents.

[0019] In this specification, unless otherwise specified, the aromatic ring or aromatic ring group may be monocyclic or polycyclic (e.g., 2 to 6 rings). A monocyclic aromatic ring is an aromatic ring having only one aromatic ring structure as its ring structure. A polycyclic (e.g., 2 to 6 rings) aromatic ring has a fused ring structure containing multiple monocyclic aromatic rings (e.g., 2 to 6). The monocyclic aromatic ring is preferably a 5-membered or 6-membered ring. Furthermore, the polycyclic aromatic ring is preferably a fused ring structure containing multiple monocyclic aromatic rings selected from 5-membered and 6-membered rings (e.g., 2 to 6). It is also preferable that the polycyclic aromatic ring consists of a fused ring of monocyclic aromatic rings. Unless otherwise specified, the number of ring member atoms in the above aromatic ring is preferably 5 to 20. In this specification, the "number of ring member atoms" in a ring (aromatic rings, alicyclic rings, etc.) refers to the number of atoms constituting the ring structure, and in the case of polycyclic rings, it refers to the number of atoms constituting the polycyclic ring. In this specification, unless otherwise specified, an aromatic ring may be either an aromatic hydrocarbon ring or an aromatic heterocyclic ring. When the aromatic ring is an aromatic heterocyclic ring, the number of heteroatoms it has as ring member atoms is, for example, 1 to 10. Examples of the heteroatoms include nitrogen, sulfur, oxygen, selenium, tellurium, phosphorus, silicon, and boron. Examples of the aromatic hydrocarbon rings include benzene, naphthalene, anthracene, pyrene, phenanthrene, and fluorene rings.Examples of the above aromatic heterocycles include pyridine rings, pyrimidine rings, pyridazine rings, pyrazine rings, triazine rings (e.g., 1,2,3-triazine rings, 1,2,4-triazine rings and 1,3,5-triazine rings, etc.), tetrazine rings (e.g., 1,2,4,5-tetrazine rings, etc.), quinoxaline rings, pyrrole rings, furan rings, thiophene rings, imidazole rings, oxazole rings, thiazole rings, benzopyrrole rings, benzofuran rings, benzothiophene rings, benzimidazole rings, benzoxazole rings, benzothiazole rings, naphthopyrrole rings, naphthofuran rings, naphthothiophene rings, naphtoimidazole rings, naphthoxazole rings, pyrroloimidazole rings (e.g., 5H-pyrrolo[1,2-a]imidazole rings, etc.), imidazoxazole rings (e.g., imidazo[2,1-b]oxazole rings, etc.), Thienothiazole rings (e.g., thieno[2,3-d]thiazole rings, etc.), benzothiadiazole rings, benzodithiophene rings (e.g., benzo[1,2-b:4,5-b']dithiophene rings, etc.), thienothiophene rings (e.g., thieno[3,2-b]thiophene rings, etc.), thiazolothiazole rings (e.g., thiazolo[5,4-d]thiazole rings, etc.), naphthodithiophene rings (e.g., naphtho[2,3- Examples include the [b:6,7-b']dithiophene ring, naphtho[2,1-b:6,5-b']dithiophene ring, naphtho[1,2-b:5,6-b']dithiophene ring and 1,8-dithiadicyclopenta[b,g]naphthalene ring, etc., benzothienobenzothiophene ring, dithieno[3,2-b:2',3'-d]thiophene ring, and 3,4,7,8-tetrathiadicyclopenta[a,e]pentalene ring.

[0020] In this specification, when referring to an aromatic ring group, for example, a group obtained by removing one or more hydrogen atoms (e.g., 1 to 5) from the above-mentioned aromatic ring is included. In this specification, when referring to an aromatic hydrocarbon group, for example, a group obtained by removing one or more hydrogen atoms (e.g., 1 to 5) from the above-mentioned aromatic hydrocarbon ring is included, and when referring to an aromatic heterocyclic group, a group obtained by removing one or more hydrogen atoms (e.g., 1 to 5) from the above-mentioned aromatic heterocyclic ring is included. In this specification, when referring to an aryl group, for example, a group obtained by removing one hydrogen atom from the ring corresponding to the aromatic hydrocarbon ring among the above-mentioned aromatic ring is included. In this specification, when referring to a heteroaryl group, for example, a group obtained by removing one hydrogen atom from the ring corresponding to the aromatic heterocyclic ring among the above-mentioned aromatic ring is included. In this specification, when referring to an arylene group, for example, a group obtained by removing two hydrogen atoms from the ring corresponding to the aromatic hydrocarbon ring among the above-mentioned aromatic ring is included. In this specification, when referring to a heteroarylene group, for example, it refers to a group obtained by removing two hydrogen atoms from a ring corresponding to an aromatic heterocycle among the aromatic rings mentioned above. In an optionally substituted aromatic ring group, an optionally substituted aryl group, an optionally substituted heteroaryl group, an optionally substituted arylene group, and an optionally substituted heteroarylene group, the types of substituents that these groups may have include, for example, the group exemplified by substituent W. When these groups have substituents, the number of substituents may be one or more (for example, 1 to 4, etc.).

[0021] In this specification, a non-aromatic ring refers to a ring structure that does not fall under the category of aromatic, and examples include aliphatic hydrocarbon rings and aliphatic heterocycles. Examples of aliphatic hydrocarbon rings include cycloalkanes, cycloalkenes, and cycloalkynes. Examples of aliphatic heterocycles include pyrrolidine rings, oxolane rings, thiolane rings, piperidine rings, tetrahydropyran rings, thiane rings, piperazine rings, morpholine rings, quinuclidine rings, azetidine rings, oxetane rings, aziridine rings, dioxane rings, and γ-butyrolactone rings. In this specification, when referring to an aliphatic hydrocarbon ring group, examples include a group obtained by removing one or more hydrogen atoms (e.g., 1 to 5) from a ring corresponding to an aliphatic hydrocarbon ring. In this specification, when referring to an aliphatic heterocycle group, examples include a group obtained by removing one or more hydrogen atoms (e.g., 1 to 5) from a ring corresponding to an aliphatic heterocycle.

[0022] In this specification, if a single formula representing a chemical structure contains multiple identical symbols indicating the type or number of groups, unless otherwise specified, the meanings of these multiple identical symbols are independent of each other, and the meanings of these identical symbols may be the same or different. In this specification, if a single formula representing a chemical structure contains multiple groups of the same kind (e.g., alkyl groups), unless otherwise specified, the specific meanings of these multiple groups of the same kind are independent of each other, and the specific meanings of these groups of the same kind may be the same or different.

[0023] In this specification, the bonding direction of the divalent group (e.g., -CO-O-) is not limited unless otherwise specified. For example, in a compound represented by the formula "X-Y-Z", if Y is -CO-O-, the compound may be either "X-O-CO-Z" or "X-CO-O-Z".

[0024] In this specification, with respect to compounds that may have geometric isomers (cis-trans isomers), the general formula or structural formula representing the compound may, for convenience, be described in only one form, either the cis or trans isomer. Even in such cases, unless otherwise specified, the form of the compound is not limited to either the cis or trans isomer, and the compound may be in either the cis or trans form. Furthermore, in this specification, with respect to compounds having a chiral atom, the general formula or structural formula representing the compound may, for convenience, be described without distinguishing between stereoisomers. Even in such cases, unless otherwise specified, the form of the compound is not limited to either form, and may be either one form or a mixture thereof. For example, a compound having a chiral carbon atom may, unless otherwise specified, be either the S or R isomer, or a mixture thereof.

[0025] In this specification, unless otherwise specified, the asterisk (*) in formulas indicates a bonding position.

[0026] [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 that order, wherein the photoelectric conversion film contains a compound represented by formula (1) or formula (2) described later (hereinafter also referred to as the "specific compound").

[0027] The reason why the photoelectric conversion element having the above configuration can solve the problems of the present invention is not necessarily clear, but the inventors speculate as follows. Note that the following speculation does not limit the mechanism by which the effect is obtained. In other words, even if the effect is obtained by a mechanism other than the one described below, it is still within the scope of the present invention. The specific compound has a predetermined fused ring containing a heteroatom at its terminal, so the HOMO orbital is extended to the terminal and has excellent interaction between terminals. For this reason, the charge transport between the specific compound is excellent not only in the stacking direction of the π-conjugated plane but also in the direction of the molecular axis. Because the photoelectric conversion film of the present invention contains such a specific compound, charge can be efficiently transported even when the electric field strength is low, and as a result, the electric field strength dependence of the response speed is considered to be small. Hereinafter, a smaller electric field strength dependence of the response speed will also be referred to as "the effect of the present invention is better."

[0028] Figure 1 shows a schematic 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 that functions 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 that functions as an upper electrode are stacked in this order. Figure 2 shows an example of the configuration of another photoelectric conversion element. The photoelectric conversion element 10b shown in Figure 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 on the lower electrode 11 in this order. Note that the stacking order of the electron blocking film 16A, the photoelectric conversion film 12, and the hole blocking film 16B in Figures 1 and 2 may be appropriately changed depending on the application and characteristics.

[0029] In the photoelectric conversion element 10a (or 10b), it is preferable that light is incident on the photoelectric conversion film 12 via the upper electrode 15. Furthermore, when using the photoelectric conversion element 10a (or 10b), a voltage can be applied. In this case, the lower electrode 11 and the upper electrode 15 form a pair of electrodes, and between this pair of electrodes, 1 × 10⁻¹⁰ －５ ~1 x 10 ７It is preferable to apply a voltage of V / cm. In terms of performance and power consumption, the applied voltage should be 1 × 10⁻⁶. －４ ~1 x 10 ７ V / cm is more preferable, 1 × 10 －３ ~5 x 10 ６ A voltage of V / cm is even more preferable. Regarding the voltage application method, it is preferable to apply the voltage so that the electron blocking film 16A side becomes the cathode and the photoelectric conversion film 12 side becomes the anode, as shown in Figures 1 and 2. The same method can be used to apply the voltage when the photoelectric conversion element 10a (or 10b) is used as a light sensor or when it is incorporated into an image sensor. As will be described in detail later, the photoelectric conversion element 10a (or 10b) is suitably applicable to image sensor applications. The configuration of each layer constituting the photoelectric conversion element of the present invention will be described in detail below.

[0030] [Photoelectric conversion film] The photoelectric conversion element has a photoelectric conversion film.

[0031] <Specific Compounds> The photoelectric conversion film contains specific compounds, which are compounds represented by formula (1).

[0032]

[0033] In equations (1) and (2), X １ Each of these independently represents either a sulfur atom or a selenium atom, and a sulfur atom is preferred in that it exhibits superior effects compared to the present invention.

[0034] In equations (1) and (2), Y independently represents a base represented by equation (3) or equation (4).

[0035]

[0036] In formula (4), X ２ X represents a sulfur atom, an oxygen atom, or a selenium atom, and a sulfur atom is preferred in that the effects of the present invention are superior. In formulas (3) and (4), X ３ Each of these is independently -CR １ = or represents a nitrogen atom, -CR １ = is preferable. R １ R represents a hydrogen atom, a fluorine atom, or a chlorine atom. １ If there are multiple instances of R, then there are multiple instances of R１ These elements may be identical or different from each other. * indicates a joining position.

[0037] In the groups represented by formulas (3) and (4), the total number of fluorine atoms and chlorine atoms is preferably 0 to 2, and more preferably 0 or 1.

[0038] In formulas (1) and (2), n independently represents 0 or 1, and 0 is preferred in that the effects of the present invention are superior.

[0039] In formulas (1) and (2), Z independently represents a group represented by any of formulas (5) to (19), and a group represented by any of formulas (5) to (9) is preferred in that the effects of the present invention are superior.

[0040]

[0041] In formulas (5) to (19), X ４ Each of these independently represents a sulfur atom, an oxygen atom, or a selenium atom, and a sulfur atom is preferred in that it exhibits superior effects compared to the present invention. ５ Each of these is independently -CR ２ = or represents a nitrogen atom, and in terms of having superior effects in the present invention, -CR ２ = is preferable. R ２ R represents a hydrogen atom, a fluorine atom, or a chlorine atom. ２ If there are multiple instances of R, then there are multiple instances of R １ These elements may be identical or different from each other. * indicates a joining position.

[0042] In the groups represented by formulas (5) to (19), the total number of fluorine atoms and chlorine atoms is preferably 0 to 2, and more preferably 0 or 1.

[0043] In particular, certain compounds are X ３ ga-CR １ = and X ５ ga-CR ２ It is preferable that the following conditions are met. Also, the specific compound is X １ , X ２ , and X ４ However, it is also preferable that all of them be sulfur atoms.

[0044] The molecular weight of the specific compound is preferably 900 to 400, more preferably 800 to 450, and even more preferably 750 to 500. It is presumed that when the molecular weight is as described above, the sublimation temperature of the specific compound will be lower, resulting in excellent manufacturability.

[0045] The specific compound can be suitably used as a p-type organic semiconductor material. A p-type organic semiconductor material is a donor organic semiconductor material (compound) that is an organic compound that readily donates electrons. The ionization potential of the specific compound is preferably 5.0 to 6.0 eV.

[0046] The maximum absorption wavelength of the specific compound is preferably in the range of 300 to 600 nm, and more preferably in the range of 300 to 500 nm. The above maximum absorption wavelength is the value measured in solution (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 does not dissolve in chloroform, the maximum absorption wavelength of the specific compound is determined by measuring the value obtained using the specific compound in the form of a film after deposition.

[0047] The specific compound is particularly useful as a material for photoelectric conversion films used in image sensors, optical sensors, or photocells. While the specific compound often functions as a p-type organic semiconductor within the photoelectric conversion film, its function and mechanism of action are not particularly limited. Furthermore, the specific compound can also be used as a coloring material, liquid crystal material, organic semiconductor material, charge transport material, pharmaceutical material, and fluorescent diagnostic material.

[0048] The specific compound may be purified as needed. Examples of purification methods for the specific compound include sublimation purification, purification using silica gel column chromatography, purification using gel permeation chromatography, slurry washing, reprecipitation purification, purification using adsorbents such as activated carbon, and recrystallization purification.

[0049] The content of the specific compound in the photoelectric conversion film (= film thickness of the specific compound on a single-layer basis / film thickness of the photoelectric conversion film × 100) is not particularly limited, but is preferably 15 to 75 volume%, more preferably 20 to 60 volume%, and even more preferably 25 to 50 volume%. Only one specific compound may be used, or two or more may be used. When two or more are used, it is preferable that their total amount is within the above range.

[0050] Furthermore, the photoelectric conversion film may further contain a p-type organic semiconductor different from the specified compound. If the photoelectric conversion film contains a p-type organic semiconductor different from the specified compound, it is also preferable that the total amount of the specified compound and the p-type organic semiconductor different from the specified compound satisfies the above range.

[0051] Photoelectric conversion films containing specific compounds are non-luminescent films and have characteristics different from organic light-emitting diodes (OLEDs). A non-luminescent film is defined as 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.

[0052] <n-type organic semiconductor> The photoelectric conversion film preferably contains an n-type organic semiconductor in addition to the specified compounds mentioned above. The n-type organic semiconductor is a compound different from the specified compounds mentioned above. The n-type organic semiconductor is an acceptor organic semiconductor material (compound), and refers to an organic compound that has the property of readily accepting electrons. In other words, the n-type organic semiconductor is the organic compound with the greater electron affinity when two organic compounds are used in contact. In other words, any organic compound that has electron-accepting properties can be used as an acceptor organic semiconductor. Examples of n-type organic semiconductors include fullerenes selected from the group consisting of fullerenes and their derivatives; condensed aromatic carbocyclic compounds (e.g., naphthalene derivatives, anthracene derivatives, phenanthrene derivatives, tetracene derivatives, pyrene derivatives, perylene derivatives, and fluorantene derivatives); and heterocyclic compounds of 5 to 7 membered rings having at least one atom selected from the group consisting of nitrogen, oxygen, and sulfur atoms (e.g., pyridine, pyrazine, pyrimidine, pyridazine, triazine, quinoline, quinoxaline, quinazoline, phthalazine, cinnoline, isoquinoline, pteridine, acridine, phenazine, phenanthroline, tetrazole, pyrazole, imidazole, and thiazole, etc.). ); polyarylene compounds; fluorene compounds; cyclopentadiene compounds; silyl compounds; 1,4,5,8-naphthalenetetracarboxylic acid dianhydride; 1,4,5,8-naphthalenetetracarboxylic acid diimide derivatives; anthraquinodimethane derivatives; diphenylquinone derivatives; bathocuproine, bathophenanthroline, and their derivatives; triazole compounds; distylyl arylene derivatives; metal complexes having nitrogen-containing heterocyclic compounds as ligands; silole compounds; 3,4,9,10-perylenetetracarboxylic acid dianhydride; 3,4,9,10-perylenetetracarboxylic acid diimide derivatives; and the compounds described in paragraphs

[0056] to

[0057] of Japanese Patent Application Publication No. 2006-100767.

[0053] As the n-type organic semiconductor (compound), fullerenes selected from the group consisting of fullerenes and their derivatives are preferred. For example, fullerene C ６０ , Fullerene C ７０, Fullerene C ７６ , Fullerene C ７８ , Fullerene C ８０ , Fullerene C ８２ , Fullerene C ８４ , Fullerene C ９０ , Fullerene C ９６ , Fullerene C ２４０ , Fullerene C ５４０ Examples include , and mixed fullerenes. Fullerene derivatives include, for example, compounds obtained by adding substituents to the above fullerene. Preferred substituents are alkyl groups, aryl groups, or heterocyclic groups. As fullerene derivatives, compounds described in Japanese Patent Application Publication No. 2007-123707 are preferred.

[0054] The molecular weight of the n-type organic semiconductor is preferably 200 to 1,200, and more preferably 200 to 900.

[0055] The maximum absorption wavelength of the n-type organic semiconductor is preferably 400 nm or less, or in the range of 500 to 600 nm.

[0056] The photoelectric conversion film preferably has a bulk heterostructure formed in a mixed state of a specific compound and an n-type organic semiconductor. Furthermore, if the photoelectric conversion film contains a dye described later, it is preferable that it has a bulk heterostructure formed in a mixed state of the specific compound, the n-type organic semiconductor, and the dye. The bulk heterostructure is a layer in the photoelectric conversion film in which the specific compound and the n-type organic semiconductor (or, if it contains a dye described later, the specific compound, the n-type organic semiconductor, and the dye) 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 Japanese Patent Application Publication No. 2005-303266.

[0057] The n-type organic semiconductor may be used alone or in combination of two or more types. When the photoelectric conversion film contains an n-type organic semiconductor, the content of the n-type organic semiconductor in the photoelectric conversion film (film thickness of the n-type organic semiconductor on a single-layer basis / film thickness of the photoelectric conversion film × 100) is preferably 15 to 75 volume%, more preferably 20 to 60 volume%, and even more preferably 20 to 50 volume%.

[0058] When the n-type organic semiconductor contains fullerenes, the content of fullerenes relative to the total content of the n-type organic semiconductor (film thickness of fullerenes on a single-layer basis / total film thickness of each n-type organic semiconductor on a single-layer basis × 100) is preferably 50 to 100 volume%, and more preferably 80 to 100 volume%. Fullerenes may be used individually or in combination of two or more types.

[0059] In terms of the response speed of the photoelectric conversion element, the content of the specific compound relative to the total content of the specific compound and the n-type organic semiconductor (film thickness of the specific compound on a single-layer basis / (film thickness of the specific compound on a single-layer basis + film thickness of the n-type organic semiconductor on a single-layer basis) × 100) is preferably 20 to 80 volume%, and more preferably 40 to 80 volume%. When the photoelectric conversion film contains an n-type organic semiconductor and a dye described later, the content of the specific compound (film thickness of the specific compound on a single-layer basis / (film thickness of the specific compound on a single-layer basis + film thickness of the n-type organic semiconductor on a single-layer basis + film thickness of the dye on a single-layer basis) × 100) is preferably 10 to 75 volume%, and more preferably 15 to 50 volume%. It is preferable that the photoelectric conversion film is substantially composed of the specific compound, an n-type organic semiconductor, and a dye included as desired. "Substantial" means that the total content of the specific compound, n-type organic semiconductor, and dye relative to the total volume of the photoelectric conversion film is 90 to 100% by volume, preferably 95 to 100% by volume, and more preferably 99 to 100% by volume.

[0060] <Dyes> The photoelectric conversion film preferably contains a dye. The dye is a compound different from the specified compound mentioned above. Organic dyes are preferred as the dye. 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, squarylium dyes, croconium dyes, azametine dyes, coumarin dyes, allylidene 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, and Examples of organic dyes include cridinone dyes, diphenylamine dyes, quinophthalone dyes, phenoxazine dyes, phthaloperylene dyes, dioxane dyes, porphyrin dyes, chlorophyll dyes, phthalocyanine dyes, subphthalocyanine dyes, metal complex dyes, imidazoquinoxaline dyes described in WO2020 / 013246, WO2022 / 168856, Japanese Patent Publication No. 2023-010305, and Japanese Patent Publication No. 2023-010299, as well as acceptor-donor-acceptor type dyes in which two acidic nuclei are bound to a donor, and donor-acceptor-donor type dyes in which two donors are bound to an acceptor. Among the organic dyes, triphenylmethane dyes, imidazoquinoxaline dyes, or acceptor-donor-acceptor type dyes are preferred.

[0061] The maximum absorption wavelength of the dye is preferably in the visible light region, and more preferably in the range of 400 to 650 nm.

[0062] The dye may be used alone or in combination of two or more types. The dye content in the photoelectric conversion film (= film thickness of the dye on a single-layer basis / film thickness of the photoelectric conversion film × 100) is preferably 15 to 85 volume%, more preferably 20 to 60 volume%, and even more preferably 25 to 40 volume%. The dye content in the photoelectric conversion film relative to the total content of the specific compound and the dye (= (film thickness of the dye on a single-layer basis / (film thickness of the specific compound on a single-layer basis + film thickness of the dye on a single-layer basis) × 100)) is preferably 15 to 75 volume%, more preferably 20 to 65 volume%, and even more preferably 25 to 60 volume%.

[0063] The dye is preferably of -5.0 to -6.0 eV as a single film, in terms of energy level matching with the n-type organic semiconductor.

[0064] The difference in ionization potential between the dye and the specific compound is preferably 0.1 eV or greater. Furthermore, the difference in ionization potential between the dye and the n-type semiconductor material is also preferably 0.1 eV or greater.

[0065] <Method of Film Formation> As a method for forming the above-mentioned photoelectric conversion film, for example, a dry film formation method can be used. Examples of dry film formation methods include vapor deposition (especially vacuum deposition), sputtering, ion plating, and physical vapor deposition methods such as MBE (Molecular Beam Epitaxy), as well as CVD (Chemical Vapor Deposition) methods such as plasma polymerization, with vacuum deposition being preferred. When forming a photoelectric conversion film by vacuum deposition, manufacturing conditions such as the degree of vacuum and deposition temperature can be set according to conventional methods.

[0066] The film thickness of the photoelectric conversion film is preferably 10 to 1000 nm, more preferably 50 to 800 nm, and even more preferably 50 to 500 nm.

[0067] [Electrodes] The photoelectric conversion element preferably has electrodes. The electrodes (upper electrode (transparent conductive film) 15 and lower electrode (conductive film) 11) are made of a conductive material. Examples of conductive materials include metals, alloys, metal oxides, electrically conductive compounds, and mixtures thereof. Since light is incident from the upper electrode 15, it is preferable that the upper electrode 15 is transparent to the light to be detected. Being transparent to the light to be detected means that the average transmittance of light in the wavelength range to be detected is 50% or more, preferably 60% or more, and more preferably 70% or more. Specifically, it is preferable that it be transparent to light with a wavelength of 400 to 800 nm. The above transmittance can be measured using a spectrophotometer. Examples of materials constituting the upper electrode 15 include conductive metal oxides such as antimony tin oxide (ATO, FTO) doped with antimony or fluorine, tin oxide, zinc oxide, indium oxide, indium tin oxide (ITO), 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, as well as nanocarbon materials such as carbon nanotubes and graphene. Conductive metal oxides are preferred in terms of high conductivity and transparency.

[0068] Typically, when a conductive film is made thinner than a certain range, its resistance often increases sharply. In the solid-state image sensor incorporating the photoelectric conversion element according to this embodiment, the sheet resistance may be 100 to 10000 Ω / □, and there is a great degree of freedom in the range of film thickness that can be thinned. Also, the thinner the upper electrode (transparent conductive film) 15, the less light it absorbs, and generally the light transmittance increases. An increase in light transmittance is desirable because it increases light absorption in the photoelectric conversion film and increases the photoelectric conversion ability. Considering the suppression of leakage current, the increase in the resistance of the thin film, and the increase in transmittance associated with thinning, the thickness of the upper electrode 15 is preferably 5 to 100 nm, and more preferably 5 to 20 nm.

[0069] The lower electrode 11 may be made transparent or opaque to reflect light, depending on the application. The definition of transparency in the lower electrode 11 is the same as that for the upper electrode 15 described above. Examples of materials that make up 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 zinc indium 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; organic conductive materials such as polyaniline, polythiophene, and polypyrrole; and carbon materials such as carbon nanotubes and graphene.

[0070] The method for forming electrodes can be appropriately selected depending on the electrode material. Specifically, 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 include electron beam methods, sputtering, resistance heating deposition, chemical reaction methods (sol-gel method, etc.), and coating of indium tin oxide dispersions.

[0071] [Charge-blocking films: electron-blocking films, hole-blocking films] It is preferable that the photoelectric conversion element has one or more intermediate layers between the conductive film and the transparent conductive film, in addition to the photoelectric conversion film. An example of the above intermediate layer is a charge-blocking film. When the photoelectric conversion element has this film, the characteristics of the resulting photoelectric conversion element (quantum efficiency, response speed, etc.) are better. Examples of charge-blocking films include electron-blocking films and hole-blocking films.

[0072] <Electron Blocking Film> The electron blocking film is a donor organic semiconductor material (compound), and for example, the following p-type organic semiconductors can be used. The above-mentioned specific compounds can also be used.

[0073] Examples of p-type organic semiconductors include triarylamine compounds (e.g., N,N'-diphenyl-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 Japanese Patent Publication No. 2011-228614, compounds described in paragraphs

[0052] to

[0063] of Japanese Patent Publication No. 2011-176259, and compounds described in paragraphs

[0119] to

[0158] of Japanese Patent Publication No. 2011-225544) Compounds, compounds described in paragraphs

[0044] to

[0051] of Japanese Patent Publication No. 2015-153910, and compounds described in paragraphs

[0086] to

[0090] of Japanese Patent Publication No. 2012-094660, etc.), 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][1]benzothiophene (BTBT) derivatives, thieno[3,2-f:4,5-f']bis[1]be Nzothiophene (TBBT) derivatives, compounds described in paragraphs

[0031] to

[0036] of JP 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, compounds described in paragraphs

[0015] to

[0025] of WO 2018 / 207722, and compounds described in paragraph

[004] of JP 2019-054228. Compounds described in paragraphs [5] to

[0053] , compounds described in paragraphs

[0045] to

[0055] of WO2019 / 058995, compounds described in paragraphs

[0063] to

[0089] of WO2019 / 081416, compounds described in paragraphs

[0033] to

[0036] of JP 2019-080052, compounds described in paragraphs

[0044] to

[0054] of WO2019 / 054125, compounds described in paragraphs

[0041] to

[0046] of WO2019 / 093188, compounds described in paragraphs

[0034] to

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

[0033] to

[0036] of Japanese Patent Publication No. 2018-206878, the compounds described in paragraph

[0038] of Japanese Patent Publication No. 2018-190755, the compounds described in paragraphs

[0019] to

[0021] of Japanese Patent Publication No. 2018-026559, the compounds described in paragraphs

[0031] to

[0056] of Japanese Patent Publication No. 2018-170487, the compounds described in paragraphs

[0036] to

[0041] of Japanese Patent Publication No. 2018-078270, and Japanese Patent Publication No. 2018-166200 The compounds described in paragraphs

[0055] to

[0082] of the Patent Publication No. 2018-113425, the compounds described in paragraphs

[0041] to

[0050] of the Patent Publication No. 2018-085430, the compounds described in paragraphs

[0044] to

[0048] of the Patent Publication No. 2018-056546, the compounds described in paragraphs

[0041] to

[0045] of the Patent Publication No. 2018-046267, and paragraphs

[0042] to

[0049] of the Patent Publication No. 2018-014474 Examples include compounds described in

[0031] to

[0036] , compounds described in paragraphs

[0036] to

[0046] of WO2018 / 016465, and compounds described in paragraphs

[0045] to

[0048] of Japanese Patent Application Publication No. 2020-010024, etc.), cyanine compounds, oxonol compounds, polyamine compounds, indole compounds, pyrrole compounds, pyrazole compounds, polyarylene compounds, condensed aromatic carbocyclic compounds (e.g., naphthalene derivatives, anthracene derivatives, phenanthrene derivatives, tetracene derivatives, pentacene derivatives, pyrene derivatives, perylene derivatives, and fluorantene derivatives, etc.), porphyrin compounds, phthalocyanine compounds, triazole compounds, oxadiazole compounds, imidazole compounds, polyarylalkane compounds, pyrazolone compounds, aminosubstituted chalcone compounds, oxazole compounds, fluorenone compounds, silazane compounds, and metal complexes having nitrogen-containing heterocyclic compounds as ligands. Furthermore, as p-type organic semiconductors, benzoxazole compounds (for example, the compounds described in Figures 3 to 7 of Japanese Patent Publication No. 2022-123944), dicarbazole compounds (for example, the compounds described in Figures 2 to 5 of Japanese Patent Publication No. 2022-122839), benzoquinazoline compounds (for example, the compounds described in paragraphs

[0053] to

[0056] of Japanese Patent Publication No. 2022-120323),Azine compounds (for example, compounds described in paragraphs

[0041] to

[0042] of Japanese Patent Publication No. 2022-120273), compounds described in Figures 2 to 10 of Japanese Patent Publication No. 2022-115832, indrotriphenylene compounds (for example, compounds described in paragraphs

[0065] to

[0072] of Japanese Patent Publication No. 2022-108268), indrocarbazole compounds (for example, paragraphs

[0052] to [00 Examples include compounds described in paragraph

[0028] of Japanese Patent Publication No. 2022-100258, triscarbazolylphenyl compounds (for example, compounds described in paragraphs

[0038] to

[0040] of Japanese Patent Publication No. 2022-181226), compounds described in paragraphs

[0070] to

[0082] of Japanese Patent Publication No. 2022-027575, and compounds described in paragraphs

[0051] to

[0064] of Japanese Patent Publication No. 2021-163968. As p-type organic semiconductors, for example, compounds with a smaller ionization potential than n-type organic semiconductors can be used, and if this condition is met, the organic dyes exemplified as n-type organic semiconductors can be used. Examples of compounds that can be used as p-type organic semiconductor compounds are given below.

[0074]

[0075]

[0076]

[0077]

[0078] Furthermore, polymer materials can also be used as electron-blocking films. Examples of polymer materials include polymers such as phenylenevinylene, fluorene, carbazole, indole, pyrene, pyrrole, picoline, thiophene, acetylene, and diacetylene, as well as their derivatives.

[0079] Furthermore, the electron blocking film may be composed of multiple films. The electron blocking film may also be composed of inorganic materials. Generally, inorganic materials have a higher dielectric constant than organic materials, so when inorganic materials are used for the electron blocking film, a higher voltage is applied to the photoelectric conversion film, resulting in higher quantum efficiency. Examples of inorganic materials that can be used as electron blocking films 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.

[0080] <Hole Blocking Film> The hole blocking film is an acceptor-type organic semiconductor material (compound), and the above-mentioned n-type organic semiconductor can be used. The hole blocking film may also be composed of multiple films.

[0081] Examples of methods for manufacturing charge-blocking films include dry deposition and wet deposition. Examples of dry deposition methods include vapor deposition and sputtering. Vapor deposition can be either physical vapor deposition (PVD) or chemical vapor deposition (CVD), with physical vapor deposition methods such as vacuum deposition being preferred. Examples of wet deposition methods include inkjet, spray, nozzle printing, spin coating, dip coating, casting, die coating, roll coating, bar coating, and gravure coating, with inkjet being preferred in terms of high-precision patterning.

[0082] The thickness of the charge blocking film (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, respectively.

[0083] [Substrate] The photoelectric conversion element may further have a substrate. Examples of substrates include semiconductor substrates, glass substrates, and plastic substrates. Typically, the substrates are layered on the substrate in the following order: conductive film, photoelectric conversion film, and transparent conductive film.

[0084] [Sealing Layer] The photoelectric conversion element may further have a sealing layer. Photoelectric conversion materials can be significantly degraded in performance due to the presence of degradation factors such as water molecules. Therefore, the entire photoelectric conversion film can be sealed by covering it with a sealing layer made of a dense metal oxide, metal nitride or metal nitride oxide ceramic, or diamond-like carbon (DLC), which does not allow water molecules to penetrate, thereby preventing the above-mentioned degradation. Examples of sealing layers include the sealing layers described in paragraphs

[0210] to

[0215] of Japanese Patent Application Publication No. 2011-082508, and the contents of these are incorporated herein.

[0085] [Method for Manufacturing a Photoelectric Conversion Element] Known manufacturing methods can be used to manufacture a photoelectric conversion element. Specifically, for example, a method for manufacturing a photoelectric conversion element can be used that includes the steps of forming a conductive film on a substrate, forming a photoelectric conversion film, and forming a transparent conductive film. The method for manufacturing a photoelectric conversion element may also include other steps (for example, a step of forming a charge blocking film and a step of forming a sealing layer). The method for forming each layer is as described above.

[0086] [Image Sensor] One example of an application of photoelectric conversion elements is an image sensor. An image sensor is an element that converts the optical information of an image into an electrical signal. Typically, multiple photoelectric conversion elements are arranged in a matrix on the same plane, and each photoelectric conversion element (pixel) converts the optical signal into an electrical signal, and these electrical signals can be output sequentially to the outside of the image sensor for each pixel. For this purpose, each pixel is composed of one or more photoelectric conversion elements and one or more transistors. The method of manufacturing an image sensor is not particularly limited, but one example is a method that includes the process of manufacturing the photoelectric conversion elements described above.

[0087] [Optical Sensor] Other applications 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 it may be used as a line sensor in which the photoelectric conversion elements are arranged in a straight line or as a two-dimensional sensor arranged on a plane.

[0088] [Compounds] This invention also includes inventions of specific compounds.

[0089] The present invention will be described in more detail below based on the following examples. The materials, amounts used, proportions, processing content, and processing procedures shown in the following examples can be modified as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be interpreted as being limited by the following examples.

[0090] [Compounds used in photoelectric conversion films] The following lists the materials used in photoelectric conversion films.

[0091] [Synthesis of Compound 1-1] Compound 1-1 was synthesized according to the following scheme.

[0092]

[0093] Compound 1-a (3.5 g, 3.8 mmol), compound 1-b (2.5 g, 11.4 mmol), and o-Tol. 3P (tri(o-tolyl)phosphine, 0.14 g, 46 mmol) were placed in a three-necked flask, 4-MeTHP (4-methyltetrahydropyran, 142 mL) was added and the mixture was stirred. Under a nitrogen atmosphere, degassing under reduced pressure and nitrogen purging were repeated three times. Then Pd ２ dba ３ (Tris(dibenzylideneacetone)dipalladium (0), 0.11 g, 0.12 mmol) was added, followed by degassing under reduced pressure and nitrogen purging, and the mixture was heated and stirred at an ambient temperature of 100°C for 4 hours. The solid was then filtered off by hot filtration. The obtained solid was washed by heating suspension in the following order: DMAc (N,N-dimethylacetamide, 150 mL, ambient temperature 120°C), THF (tetrahydrofuran, 150 mL, ambient temperature 80°C), and toluene (150 mL, ambient temperature 120°C). The obtained solid was dried under reduced pressure and purified by sublimation to obtain compound 1-1 (1.2 g, yield 52%). The structure of the product was confirmed by field desorption-mass spectrometry (FD-MS).

[0094] The specific compounds used in each example of the photoelectric conversion film, other than compound 1-1, can be synthesized in accordance with the synthesis method of compound 1-1. The comparative compounds in each comparative example can be synthesized by the method described in International Publication No. 2019 / 054125.

[0095] [Specific Compounds and Comparative Compounds] The specific compounds used in the photoelectric conversion film and comparative compounds of the comparative examples are shown below. Compounds 1-1 to 1-28 are specific compounds, and compounds 2-1 to 2-9 are comparative compounds.

[0096]

[0097]

[0098]

[0099] [n-type organic semiconductor] ・C ６０ : Fullerene (C ６０ )

[0100] [Pigment]

[0101]

[0102] [Evaluation] The response speed of the photoelectric conversion element in each example and comparative example, and the dependence of the response speed on the electric field strength, will be evaluated using the following method.

[0103] [Fabrication of Photoelectric Conversion Element] A photoelectric conversion element in the form shown in Figure 2 is fabricated using the various components shown above. Here, the photoelectric conversion element consists of a lower electrode 11, an electron blocking film 16A, a photoelectric conversion film 12, a hole blocking film 16B, and an upper electrode 15. Specifically, amorphous ITO is deposited on a glass substrate by sputtering to form the lower electrode 11 (thickness: 30 nm), and then a compound (EB-1) is deposited on the lower electrode 11 by vacuum heating deposition to form the electron blocking film 16A (thickness: 30 nm). Subsequently, with the glass substrate at room temperature, each specific compound or each comparative compound shown in the table below and an n-type organic semiconductor (fullerene (C)) are deposited on the electron blocking film 16A. ６０The compound (EB-2) and the dyes shown in the table below are co-deposited by vacuum deposition so that the ratio of the specific compound or each comparative compound / n-type organic semiconductor / dye is 1 / 1 / 1 (in terms of film thickness). This forms a photoelectric conversion film 12 having a bulk heterostructure with a thickness of 400 nm. Further, the compound (EB-2) is deposited on the photoelectric conversion film 12 to form a hole blocking film 16B (thickness: 10 nm). Amorphous ITO is deposited on the hole blocking film 16B by sputtering to form an upper electrode 15 (transparent conductive film) (thickness: 10 nm). An SiO film is formed on the upper electrode 15 as a sealing layer by vacuum deposition, and then aluminum oxide (Al) is deposited on it by ALCVD (Atomic Layer Chemical Vapor Deposition). ２ O ３ A layer is formed. A photoelectric conversion element can be fabricated by the above procedure.

[0104]

[0105] [Dark Current] The dark current of each obtained photoelectric conversion element is measured using the following method. 2.5 × 10⁻¹⁰ ions are applied to the lower and upper electrodes of each photoelectric conversion element. ５ A voltage was applied to achieve an electric field strength of V / cm, and the current value in the dark (dark current) was measured. As a result, the dark current for all photoelectric conversion elements was 50 nA / cm. ２ The following results are observed, indicating a sufficiently low dark current.

[0106] [Quantum Efficiency] The quantum efficiency of each photoelectric conversion element is measured using the following method: 2.0 × 10⁻¹⁶ for each photoelectric conversion element. ５ A voltage is applied to achieve an electric field strength of V / cm. Then, light is irradiated from the upper electrode (transparent conductive film) side, and the quantum efficiency (photoelectric conversion efficiency) at a wavelength of 560 nm is evaluated. All photoelectric conversion elements exhibit an external quantum efficiency of 30% or more.

[0107] [Response Speed] The response speed of each photoelectric conversion element is evaluated using the following method: 2.0 × 10⁻¹⁶ ５A voltage is applied to achieve an electric field strength of V / cm. Then, the LED (light emitting diode) is momentarily lit to irradiate light from the upper electrode (transparent conductive film) side, and the photocurrent at the evaluation wavelength (wavelength 500 nm or 560 nm) shown in the table below is measured with an oscilloscope to measure the rise time from 0% signal intensity to 97% signal intensity. From the obtained rise time, the relative response speed is calculated according to equation (S1). From the obtained relative response speed, the response speed is evaluated according to the evaluation criteria below. In equation (S1), the same evaluation wavelength is used for both the numerator and the denominator. For example, the relative response speed of Example A-1 is calculated as (rise time of the photoelectric conversion element of Example A-1 at a wavelength of 560 nm) / (rise time of the photoelectric conversion element of Comparative Example B-1 at a wavelength of 560 nm), and the relative response speed of Example A-4 is calculated as (rise time of the photoelectric conversion element of Example A-4 at a wavelength of 500 nm) / (rise time of the photoelectric conversion element of Comparative Example B-2 at a wavelength of 500 nm). A response speed of C or higher is preferred. Equation (S1): Relative response speed = (rise time of each photoelectric conversion element) / (rise time of the photoelectric conversion element using compound 2-1)

[0108] A: Relative response time less than 0.8 B: Relative response time 0.8 or higher, less than 0.9 C: Relative response time 0.9 or higher, less than 1.0 D: Relative response time 1.0 or higher, less than 1.2 E: Relative response time 1.2 or higher

[0109] [Dependence of response speed on electric field strength] For each photoelectric conversion element, the electric field strength dependence of the response speed is evaluated using the following method. In the evaluation of the above [response speed], the voltage applied to each photoelectric conversion element is set to an electric field strength of 7.5 × 10⁻⁶ ４ Except for changing it to V / cm, the same procedure is used to obtain an electric field strength of 7.5 × 10⁻⁶. ４The rise time at V / cm is measured. The wavelength of the photocurrent used to measure the rise time is the evaluation wavelength (wavelength 500 nm or 560 nm) shown in the table below. The electric field strength dependence of the response speed is calculated according to equation (S2) and evaluated according to the evaluation criteria below. In equation (S2), the numerator and denominator are the values ​​measured for the photoelectric conversion element of the same example or comparative example. An evaluation of B or higher for the electric field strength dependence of the response speed is preferable. Equation (S2): Electric field strength dependence of response speed = (Electric field strength of each photoelectric conversion element 7.5 × 10⁻⁶) ４ (Rise time at V / cm) / (Electric field strength of each photoelectric conversion element 2.0 × 10) ５ (Rise time at V / cm)

[0110] A: The electric field strength dependence of the response speed is less than 2.0. B: The electric field strength dependence of the response speed is 2.0 or more and less than 3.0. C: The electric field strength dependence of the response speed is 3.0 or more and less than 4.0. D: The electric field strength dependence of the response speed is 4.0 or more.

[0111] [result]

[0112] The evaluation results obtained are shown in Tables 1 and 2 below. In the tables, the "Formula (1), Formula (2)" column is "A" if the photoelectric conversion film contains a specific compound, and "B" otherwise. ３ , X ５ The "=CR" column indicates X for specific compounds. ３ ga-CR １ = and X ５ ga-CR ２ If the values ​​are equal, it is designated as "A," and otherwise it is designated as "B." In the table, the "n=0" column indicates that for a specific compound, if n is 0, it is designated as "A," and otherwise it is designated as "B." In the table, the "Z=(5)~(9)" column indicates that for a specific compound, if Z is a group represented by any of formulas (5) to (9), it is designated as "A," and otherwise it is designated as "B." In the table, "X １ , X ２ , X ４ The column labeled "=S" indicates that X is used for a specific compound. １ , X ２ , and, X ４If all atoms are sulfur atoms, it is designated as "A," and in all other cases, it is designated as "B." In the table, the "Evaluation Wavelength" column indicates the wavelength used for measurement in the evaluation of the response speed described above.

[0113]

[0114]

[0115] The results shown in Table 1 confirm that the photoelectric conversion element of the present invention exhibits low dependence of response speed on electric field strength. Furthermore, it can be confirmed that the photoelectric conversion element of the present invention also exhibits excellent response speed. A comparison of Examples A-12, A-19, and A-27 with other examples shows that X ３ ga-CR １ = and X ５ ga-CR ２ When =, it can be confirmed that the response speed is superior. From a comparison of Examples A-25 to A-28 with other examples, it can be confirmed that when n = 0, the response speed is superior and the electric field strength dependence of the response speed is smaller. From a comparison of Examples A-13 to A-22, A-28, and A-31 to A-32 with other examples, it can be confirmed that when Z is a group represented by any of equations (5) to (9), the response speed is superior and the electric field strength dependence of the response speed is smaller. From a comparison of Examples A-8 and A-9 with other examples, X １ , X ２ , and, X ４ When all of these atoms are sulfur atoms, it can be confirmed that the response speed is superior.

[0116] 10a, 10b Photoelectric conversion element 11 Conductive film (lower 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 comprising a conductive film, a photoelectric conversion film, and a transparent conductive film in this order, wherein the photoelectric conversion film comprises a compound represented by formula (1) or formula (2). In formula (1) and formula (2), X １ each independently represent a sulfur atom or a selenium atom. Each Y independently represents a group represented by formula (3) or formula (4). Each n independently represents 0 or 1. Each Z independently represents a group represented by any one of formula (5) to formula (19). In formula (4), X ２ represents a sulfur atom, an oxygen atom, or a selenium atom. In formula (3) and formula (4), X ３ each independently represents -CR １ = or a nitrogen atom. R １ represents a hydrogen atom, a fluorine atom, or a chlorine atom. When a plurality of R １ are present, the plurality of R １ may be the same or different from each other. * represents a bonding site. In formula (5) to formula (19), X ４ each independently represents a sulfur atom, an oxygen atom, or a selenium atom. X ５ each independently represents -CR ２ = or a nitrogen atom. R ２ represents a hydrogen atom, a fluorine atom, or a chlorine atom. When a plurality of R ２ are present, the plurality of R ２ may be the same or different from each other. * represents a bonding site.

2. X ３ ga-CR １ = and X ５ ga-CR ２ The photoelectric conversion element according to claim 1, wherein the value is equal to the value of the photoelectric conversion element according to claim 1.

3. The photoelectric conversion element according to claim 1, wherein n is 0.

4. The photoelectric conversion element according to claim 1, wherein Z is independently a group represented by any of the formulas (5) to (9) above.

5. X １ , X ２ , and X ４ The photoelectric conversion element according to claim 1, wherein the atom is a sulfur atom.

6. The photoelectric conversion element according to any one of claims 1 to 5, wherein the photoelectric conversion film further comprises a dye.

7. The photoelectric conversion element according to any one of claims 1 to 5, wherein the photoelectric conversion film further comprises an n-type organic semiconductor.

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

9. A photoelectric conversion element according to any one of claims 1 to 5, wherein the conductive film and the transparent conductive film are interposed between them, and one or more intermediate layers in addition to the photoelectric conversion film.

10. An image sensor having a photoelectric conversion element according to any one of claims 1 to 5.

11. A light sensor having a photoelectric conversion element according to any one of claims 1 to 5.

12. A method for manufacturing an image sensor, comprising the step of manufacturing a photoelectric conversion element according to any one of claims 1 to 5.

13. A compound represented by formula (1) or formula (2). In equations (1) and (2), X １ Each independently represents either a sulfur atom or a selenium atom. Each independently represents either the group represented by formula (3) or formula (4). Each independently represents either 0 or 1. Each independently represents any of the groups represented by formulas (5) to (19). In formula (4), X ２ X represents a sulfur atom, an oxygen atom, or a selenium atom. In formulas (3) and (4), X ３ Each of these is independently -CR １ = or represents a nitrogen atom. R １ R represents a hydrogen atom, a fluorine atom, or a chlorine atom. １ If there are multiple instances of R, then there are multiple instances of R １ These elements may be identical or different from each other. * indicates a joining position. In formulas (5) to (19), X ４ Each of these independently represents a sulfur atom, an oxygen atom, or a selenium atom. ５ Each of these is independently -CR ２ = or represents a nitrogen atom. R ２ R represents a hydrogen atom, a fluorine atom, or a chlorine atom. ２ If there are multiple instances of R, then there are multiple instances of R ２ These elements may be identical or different from each other. * indicates a joining position.

14. X ３ ga-CR １ = and X ５ ga-CR ２ The compound according to claim 13, which is equal to =.

15. The compound according to claim 13 or 14, wherein n is 0.

16. The compound according to claim 13 or 14, wherein Z is independently a group represented by any one of formulas (5) to (9).

17. X １ , X ２ , and X ４ The compound according to claim 13 or 14, wherein the atom is a sulfur atom.

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