JP2016092249A - Photoelectric conversion element and image sensor using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photoelectric conversion element having a high photoelectric conversion efficiency, and a high ratio of ON/OFF owing to the reduction in dark current.SOLUTION: A photoelectric conversion element operable to convert a light energy into an electric energy comprises: a first electrode; a second electrode; and at least one organic layer between the first and second electrodes. The organic layer includes a compound having a molecular weight of 350 or larger, and expressed by the following general formula (1). (In the formula, A and B represent a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group. which are groups different from each other; Land Lrepresent a single bond, a substituted or unsubstituted arylene group, or a substituted or unsubstituted heteroarylene group; n is 1-3, provided that when n=1, at least one of A and B is selected from a substituted or unsubstituted condensed aromatic hydrocarbon group of which the core carbon number is 9 or larger, and a substituted or unsubstituted condensed aromatic heterocyclic group of which the core carbon number is 9 or larger; and Lis a substituted or unsubstituted heteroarylene group having at least one electron-accepting nitrogen.)SELECTED DRAWING: None

Description

  The present invention relates to a photoelectric conversion photoelectric conversion element and an image sensor using the photoelectric conversion element.

  Photoelectric conversion elements that can convert light into electrical energy can be used in solar cells, image sensors, and the like. In particular, image sensors that read current generated from incident light by a photoelectric conversion element using a CCD or CMOS circuit are widely used.

  Conventionally, in an image sensor using a photoelectric conversion element, an inorganic substance is used as a material constituting the photoelectric conversion film. However, since inorganic materials have low color selectivity (absorption at specific wavelengths), incident light is selectively transmitted through each color (red, green, and blue) using a color filter, and each light is transmitted through a photoelectric conversion film. It was necessary to absorb. However, when a color filter is used, when a fine target is photographed, the pitch of the target interferes with the pitch of the image sensor, and an image (moire defect) different from the original image is generated. In order to suppress this, an optical lens or the like is required, but there is a disadvantage that the light use efficiency and the aperture ratio are lowered by the color filter and the optical lens.

  On the other hand, in recent years, the demand for high resolution of image sensors has increased, and the miniaturization of pixels has progressed. For this reason, the size of the pixel becomes smaller, but the amount of light reaching the photoelectric conversion element of each pixel decreases due to the smaller size, which causes a problem of a decrease in sensitivity.

  In order to solve this, research on photoelectric conversion elements using organic compounds has been conducted. The organic compound can selectively absorb light in a specific wavelength region out of incident light due to its molecular structure, so that a color filter is not necessary and the absorption coefficient is high, so that the light utilization efficiency can be increased. As a photoelectric conversion element using this organic compound, specifically, an element configuration in which a pn junction structure or a bulk heterojunction structure is introduced into a photoelectric conversion film sandwiched between both electrodes is known. Further, in application of an image sensor, a voltage is often applied from the outside in order to improve photoelectric conversion efficiency and response speed, so that a dark current is generated due to injection of holes or electrons from an electrode by an external electric field. An element configuration in which a hole blocking layer or an electron blocking layer is inserted for the purpose of reducing the dark current is also known (see, for example, Patent Document 1 and Patent Document 2).

JP 2007-088033 A JP 2007-059515 A

  However, Japanese Patent Application Laid-Open No. 2007-088033 discloses a preferable structure example as a hole blocking layer, but all have a highly symmetric molecular structure, a structure that is easily crystallized, and has heat resistance or durability. There is a problem. Also, JP-A-2007-059515 discloses only a group of compounds having good symmetry as a preferred structural example, and is easily crystallized during a heat treatment process at a high temperature, and lacks transparency. It does not mention issues such as short circuits.

  Accordingly, an object of the present invention is to provide a photoelectric conversion element that has excellent heat resistance, high photoelectric conversion efficiency, and reduced dark current.

  The present invention is a photoelectric conversion element that has at least one organic layer between the first electrode and the second electrode, and converts light energy into electric energy, wherein the organic layer has a molecular weight of 350 or more, It is a photoelectric conversion element characterized by containing the compound represented by following General formula (1).

In the formula, A and B are a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group. However, A and B are different groups. L ¹ and L ³ are a single bond, a substituted or unsubstituted arylene group, or a substituted or unsubstituted heteroarylene group. n is an integer of 1 to 3. However, when n = 1, at least one of A and B is a substituted or unsubstituted condensed aromatic hydrocarbon group having 9 or more nuclear carbon atoms, or substituted or unsubstituted A condensed aromatic heterocyclic group having 9 or more nuclear carbon atoms is selected. L ² is a substituted or unsubstituted heteroarylene group having at least one electron-accepting nitrogen.

  According to the present invention, a photoelectric conversion element having excellent heat resistance, high photoelectric conversion efficiency, and reduced dark current can be provided.

The schematic cross section which shows an example of the photoelectric conversion element of this invention. The schematic cross section which shows an example of the photoelectric conversion element of this invention. The schematic cross section which shows an example of the photoelectric conversion element of this invention. The schematic cross section which shows an example of the photoelectric conversion element of this invention. The schematic cross section which shows an example of the laminated structure of the photoelectric conversion element of the image sensor of this invention. The schematic cross section which shows an example of the laminated structure of the photoelectric conversion element of the image sensor of this invention. The schematic cross section which shows an example of the laminated structure of the photoelectric conversion element of the image sensor of this invention. The schematic cross section which shows an example of the laminated structure of the photoelectric conversion element of the image sensor of this invention. The schematic cross section which shows an example of the laminated structure of the photoelectric conversion element of the image sensor of this invention. The schematic cross section which shows an example of the laminated structure of the photoelectric conversion element of the image sensor of this invention.

<Photoelectric conversion element material>
The photoelectric conversion element of this invention contains the compound represented by General formula (1) in an organic layer.

In the formula, A and B are a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group. However, A and B are different groups. L ¹ and L ³ are a single bond, a substituted or unsubstituted arylene group, or a substituted or unsubstituted heteroarylene group. n is an integer of 1 to 3. However, when n = 1, at least one of A and B is a substituted or unsubstituted condensed aromatic hydrocarbon group having 9 or more nuclear carbon atoms, or substituted or unsubstituted A condensed aromatic heterocyclic group having 9 or more nuclear carbon atoms is selected. L ² is a substituted or unsubstituted heteroarylene group having at least one electron-accepting nitrogen.

  In all of the above groups, hydrogen may be deuterium. In the following description, for example, a substituted or unsubstituted aryl group having 6 to 40 carbon atoms is 6 to 40 carbon atoms including the number of carbon atoms contained in the substituent group substituted on the aryl group, and defines the carbon number. The same applies to the other substituents.

In the case of “substituted or unsubstituted”, examples of the substituent include alkyl group, cycloalkyl group, heterocyclic group, alkenyl group, cycloalkenyl group, alkynyl group, alkoxy group, alkylthio group, aryl ether group, aryl thioether Selected from the group consisting of a group, an aryl group, a heteroaryl group, an amino group, a halogen, a cyano group, a carbonyl group, a carboxyl group, an oxycarbonyl group, a carbamoyl group, and —P (═O) R ¹ R ² . R ¹ and R ² may be condensed to form a ring.

  “Unsubstituted” in the case of “substituted or unsubstituted” means that a hydrogen atom is substituted.

  In the compound described below or a partial structure thereof, the case of “substituted or unsubstituted” is the same as described above.

  The alkyl group is, for example, a saturated aliphatic hydrocarbon group such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, or a tert-butyl group, which is a substituent. It may or may not have. There is no restriction | limiting in particular in the additional substituent in the case of being substituted, For example, an alkyl group, an aryl group, heteroaryl group etc. can be mentioned, This point is common also in the following description. The number of carbon atoms of the alkyl group is not particularly limited, but is preferably 1 or more and 20 or less, more preferably 1 or more and 8 or less, from the viewpoint of availability and cost.

  The cycloalkyl group represents, for example, a saturated alicyclic hydrocarbon group such as a cyclopropyl group, a cyclohexyl group, a norbornyl group, an adamantyl group, which may or may not have a substituent. The number of carbon atoms in the alkyl group moiety is not particularly limited, but is preferably in the range of 3 or more and 20 or less.

  The heterocyclic group refers to an aliphatic ring having atoms other than carbon, such as a pyran ring, a piperidine ring, and a cyclic amide, in the ring, which may or may not have a substituent. . Although carbon number of a heterocyclic group is not specifically limited, Preferably it is the range of 2-20.

  An alkenyl group shows the unsaturated aliphatic hydrocarbon group containing double bonds, such as a vinyl group, an allyl group, and a butadienyl group, and this may or may not have a substituent. Although carbon number of an alkenyl group is not specifically limited, Preferably it is the range of 2-20.

  The cycloalkenyl group refers to an unsaturated alicyclic hydrocarbon group containing a double bond such as a cyclopentenyl group, a cyclopentadienyl group, or a cyclohexenyl group, which may have a substituent. You don't have to.

  An alkynyl group shows the unsaturated aliphatic hydrocarbon group containing triple bonds, such as an ethynyl group, for example, and may or may not have a substituent. The number of carbon atoms of the alkynyl group is not particularly limited, but is preferably in the range of 2 or more and 20 or less.

  The alkoxy group refers to, for example, a functional group having an aliphatic hydrocarbon group bonded through an ether bond such as a methoxy group, an ethoxy group, or a propoxy group, and the aliphatic hydrocarbon group may have a substituent. It may not have. Although carbon number of an alkoxy group is not specifically limited, Preferably it is the range of 1-20.

  The alkylthio group is a group in which an oxygen atom of an ether bond of an alkoxy group is substituted with a sulfur atom. The hydrocarbon group of the alkylthio group may or may not have a substituent. Although carbon number of an alkylthio group is not specifically limited, Preferably it is the range of 1-20.

  An aryl ether group refers to a functional group to which an aromatic hydrocarbon group is bonded via an ether bond, such as a phenoxy group, and the aromatic hydrocarbon group may or may not have a substituent. Good. Although carbon number of an aryl ether group is not specifically limited, Preferably, it is the range of 6-40.

  An aryl thioether group is one in which the oxygen atom of the ether bond of the aryl ether group is substituted with a sulfur atom. The aromatic hydrocarbon group in the aryl ether group may or may not have a substituent. Although carbon number of an aryl ether group is not specifically limited, Preferably, it is the range of 6-40.

  The aryl group represents an aromatic hydrocarbon group such as a phenyl group, a naphthyl group, a biphenyl group, a terphenyl group, a fluoranthenyl group, a phenanthryl group, an anthracenyl group, a pyrenyl group, or a fluoranthenyl group. The aryl group may or may not have a substituent. Although carbon number of an aryl group is not specifically limited, Preferably, it is the range of 6-40. More preferably, they are a phenyl group, 1-naphthyl group, and 2-naphthyl group.

  A heteroaryl group is a furanyl group, thiophenyl group, pyridyl group, quinolinyl group, isoquinolinyl group, pyrazinyl group, pyrimidyl group, naphthyridyl group, benzofuranyl group, benzothiophenyl group, indolyl group, dibenzofuranyl group, dibenzothiophenyl group And a cyclic aromatic group having one or more atoms other than carbon in the ring, such as a carbazolyl group, which may be unsubstituted or substituted. Although carbon number of heteroaryl group is not specifically limited, Preferably it is the range of 2-30. More preferred are a pyridyl group, a quinolyl group, a carbazolyl group, a dibenzofuranyl group, and a dibenzothienyl group.

  An amino group is a substituted or unsubstituted amino group. Examples of the substituent in the case of substitution include an aryl group, a heteroaryl group, a linear alkyl group, and a branched alkyl group. More specifically, a phenyl group, a biphenyl group, a naphthyl group, a pyridyl group, a methyl group and the like can be mentioned, and these substituents may be further substituted. Although carbon number is not specifically limited, Preferably it is the range of 6-40.

  Halogen represents an atom selected from fluorine, chlorine, bromine and iodine.

  The carbonyl group, carboxyl group, oxycarbonyl group, carbamoyl group and phosphine oxide group may or may not have a substituent. Here, examples of the substituent include an alkyl group, a cycloalkyl group, an aryl group, and a heteroaryl group, and these substituents may be further substituted.

  An arylene group refers to a divalent or higher valent group derived from an aromatic hydrocarbon group such as benzene, naphthalene, biphenyl, fluorene, phenanthrene, etc., which may or may not have a substituent. A divalent or trivalent arylene group is preferable. Specific examples of the arylene group include a phenylene group, a biphenylene group, and a naphthylene group.

  The heteroarylene group is a divalent or higher valent group derived from an aromatic group having one or more atoms other than carbon in the ring, such as pyridine, quinoline, pyrimidine, pyrazine, triazine, quinoxaline, quinazoline, dibenzofuran, dibenzothiophene. This may or may not have a substituent. A divalent or trivalent heteroarylene group is preferred. Although carbon number of heteroarylene group is not specifically limited, Preferably, it is the range of 2-30. Specific examples of the heteroarylene group include 2,6-pyridylene group, 2,5-pyridylene group, 2,4-pyridylene group, 3,5-pyridylene group, 3,6-pyridylene group, 2,4, 6-pyridylene group, 2,4-pyrimidinylene group, 2,5-pyrimidinylene group, 4,6-pyrimidinylene group, 4,6-pyrimidinylene group, 2,4,6-pyrimidinylene group, 2,4,6-triazinylene group 4,6-dibenzofuranylene group, 2,6-dibenzofuranylene group, 2,8-dibenzofuranylene group, 3,7-dibenzofuranylene group.

  The condensed aromatic hydrocarbon ring is, for example, naphthalene ring, azulene ring, anthracene ring, phenanthrene ring, pyrene ring, chrysene ring, naphthacene ring, triphenylene ring, acenaphthene ring, coronene ring, fluorene ring, fluoranthene ring, naphthacene ring, Examples include a pentacene ring, a perylene ring, a pentaphen ring, a picene ring, a pyranthrene ring, and an anthraanthrene ring. Furthermore, the condensed aromatic hydrocarbon ring may have a substituent. The number of carbon atoms in the condensed aromatic hydrocarbon ring is not particularly limited, but is preferably in the range of 10-18.

  Examples of the monocyclic aromatic heterocycle include a furan ring, a thiophene ring, a pyridine ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, an oxadiazole ring, a triazole ring, an imidazole ring, a pyrazole ring, and a thiazole ring. Furthermore, the monocyclic aromatic heterocycle may have a substituent.

  The condensed aromatic heterocycle includes, for example, a quinoline ring, isoquinoline ring, quinoxaline ring, benzimidazole ring, indole ring, benzimidazole ring, benzothiazole ring, benzoxazole ring, quinoxaline ring, quinazoline ring, phthalazine ring, carbazole ring, And a carboline ring, a diazacarbazole ring (indicating a ring in which one of the carbon atoms of the hydrocarbon ring constituting the carboline ring is further substituted with a nitrogen atom). Furthermore, the fused aromatic heterocycle may have a substituent. The number of carbon atoms of the fused aromatic heterocycle is not particularly limited, but is preferably in the range of 9-18.

  The term “nuclear carbon number” refers to the number of carbon atoms contained in the skeleton other than the substituent. For example, since the naphthyl group has 10 carbon atoms contained in the naphthalene ring, the naphthyl group has 10 nuclear carbon atoms, whether it is unsubstituted or further substituted.

  The electron-accepting nitrogen represents a nitrogen atom that forms a multiple bond with an adjacent atom. The aromatic heterocyclic ring containing electron-accepting nitrogen is, for example, a pyridine ring, pyridazine ring, pyrimidine ring, pyrazine ring, triazine ring, oxadiazole ring, thiazole ring, quinoline ring, isoquinoline ring, quinazoline ring, quinoxaline ring, Examples thereof include a benzoquinoline ring, a phenanthroline ring, an acridine ring, a benzothiazole ring, and a benzoxazole ring. Furthermore, the aromatic heterocyclic ring containing the electron-accepting nitrogen may have a substituent. Preferable examples include pyridine ring, pyrimidine ring, triazine ring, quinoline ring, isoquinoline ring, quinazoline ring, quinoxaline ring, and phenanthroline ring. More preferred are a pyridine ring, a quinoline ring, and a phenanthroline ring.

  In the compound represented by the general formula (1), when A and B are different groups, the molecule has an asymmetric structure, the crystallinity is lowered, and the glass transition temperature is increased, so that the stability of the film is improved.

  In addition, when n = 1, the molecular weight is small and the crystallinity is high. Therefore, at least one of A and B is a substituted or unsubstituted condensed aromatic hydrocarbon group and has 9 carbon atoms. It is preferable to have the above or a substituted or unsubstituted condensed aromatic heterocyclic group having 9 or more nuclear carbon atoms because the molecule becomes rigid and the stability of the film is improved.

  Moreover, it is preferable that at least one of A and B is a substituted or unsubstituted heteroaryl group. This is because the LUMO level of the compound represented by the general formula (1) becomes deep, and the electrons can be easily taken out from the photoelectric conversion layer to the anode. Furthermore, it is preferable that A is a heteroaryl group containing a nitrogen atom because the LUMO level becomes deeper. However, even if it is asymmetric, if the molecular weight is small, the crystallinity becomes high. Therefore, the molecular weight of the compound represented by the general formula (1) is preferably 350 or more, and more preferably 400 or more.

L ¹ and L ³ are a single bond, a substituted or unsubstituted arylene group, or a substituted or unsubstituted heteroarylene group from the viewpoint of improving the stability during sublimation or from the viewpoint of improving the electron mobility due to the spread of conjugation. . Of these groups, a single bond, a phenylene group, a biphenylene group, a naphthalenylene group, a pyridinylene group, a pyrimidinylene group, a triazinylene group, and the like are preferable from the viewpoint that the molecular weight is not excessively increased. As the substituent when these groups are further substituted, a methyl group, a cyano group, a phenyl group, a pyridyl group, or the like that does not increase the molecular weight is preferable. Furthermore, a cyano group or a pyridyl group improves electron withdrawing properties and facilitates extraction of electrons from the photoelectric conversion layer to the anode. As a result, the photoelectric conversion efficiency can be increased, which is more preferable.

n is an integer of 1 to 3 from the viewpoint of improving electron mobility due to conjugation spread. Furthermore, 1 or 2 is preferable because the molecular weight is too large and the synthesis is simple. Further, when n is 2, substitution of the same group for L ² spreads the LUMO orbital over the entire molecule and increases electron mobility, which is preferable. Since A and B in the general formula (1) are different substituents, even if n is 2, it is possible to improve both the electron mobility by improving the symmetry of the molecule and the stability of the film.

L ² is preferably a substituted or unsubstituted heteroarylene group having at least one electron accepting property, since the LUMO level becomes deep. Among them, specifically, pyridylene group, pyrimidinylene group, triazinylene group, quinolinylene group, isoquinolinylene group, benzoquinolinylene group, phenanthrolinylene group, dibenzoquinolinylene group, dibenzoquinoxalinylene group, benzophenylene group Nantridinylene group, naphthoquinolinylene group, benzopyrimidinylene group, indenoquinolinylene group, indenoisoquinolinylene group and the like are preferable because of high planarity and high electron mobility.

Among them, L ² is preferably a group represented by any one of the following general formulas (2) to (6).

In the formula, X ^{1 to} X ⁴⁶ represent CH, a substituted carbon atom, or a nitrogen atom. ^However, X 1, at least one to X ^6, X 7 at least one ^{to X 14,} at least one of ^X 15 ^{~X 24,} X 25, at least one ^{to X 34,} at least one X 35 ^{to X 46} Each is a nitrogen atom.

In the general formula (2), L ¹ is linked to L 1 at any ^one position among X ^{1 to} X ⁶ and L ³ or B is linked to any one other position. In the general formula (3), L ¹ is connected to L ¹ at any one position of X ^{7 to} X ¹⁴ , and L ³ or B is connected to any one other position. In the general formula (4) ^X 15 and ^{L 1} at any one of positions ^{to X 24,} respectively connect with ^{L 3} or B in one of the positions of the other. In General Formula (5), L ¹ is linked to L 1 at any ^one position of X ^{25 to} X ³⁴ and L ³ or B is linked to any one other position. In the general formula (6) and ^{L 1} at any one of positions ^X 35 ^{to X 46,} respectively connect with ^{L 3} or B in one of the positions of the other.

  As a substituent in the case of substituting with a carbon atom, a methyl group, a cyano group, a phenyl group, a pyridyl group, and the like are preferable from the viewpoint that the molecular weight does not become too large. Furthermore, the cyano group and the pyridyl group have higher electron withdrawing properties, and the LUMO level of the compound represented by the general formula (1) becomes deeper. This facilitates the extraction of electrons from the photoelectric conversion layer to the anode, and is preferable because the photoelectric conversion efficiency can be increased.

  As the number of nitrogen atoms is larger, the electron withdrawing property is increased, and the LUMO level of the compound represented by the general formula (1) is deepened, which is preferable, but in view of the ease of synthesis, the general formula (2) In general formula (3), the number of nitrogen atoms is preferably 1 or 2, and in general formula (4), the number of nitrogen atoms is preferably 2, and in general formula (5) The number of nitrogen atoms is preferably 1 or 2, and in the general formula (6), the number of nitrogen atoms is preferably 1 or 2 or 6.

Further, among these, from the viewpoint of high electron withdrawing property and easy synthesis, L ² is a substituted or unsubstituted pyrimidinylene group, a substituted or unsubstituted triazinylene group, or a substituted or unsubstituted quinazolinylene. Groups are preferred. Furthermore, a substituted or unsubstituted pyrimidinylene group is preferable from the viewpoint of ease of synthesis.

  As the substituent in the case of substitution, from the viewpoint that the molecular weight does not become too large, the cyano group and the pyridyl group have higher electron withdrawing properties and deeper LUMO levels, so that electrons from the photoelectric conversion layer to the anode It is more preferable because it can be easily taken out and the photoelectric conversion efficiency can be increased.

  B is preferably a group represented by any one of the following general formulas (7) to (12).

In the formula, Y ^{1 to} Y ⁵⁵ each independently represent CH, a substituted carbon atom or a nitrogen atom. The adjacent Y ⁱ (i = 1 to 55) may be condensed to form a ring. Z ^{1 to} Z ⁴ are each independently NR ³ , CR ⁴ R ⁵ , O or S. R ^{3 to} R ⁵ are each independently a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group. However, in the general formula (7) connects the ^{L 3} in any one of positions ^Y 1 ^{to Y 10.} In the general formula (8) is connected to the ^{L 3} in any one of positions ^Y 11 ^{to Y 21.} In the general formula (9) connects the ^{L 3} in any one of positions ^Y 22 ^{to Y 31.} In the general formula (10) is connected to the ^{L 3} in any one of positions ^Y 32 ^{to Y 43.} Of ^Y 44 ^{to Y 51} in the general formula (11), or is connected to the ^{L 3} in any one position of ^{R 3.} In the general formula (12) is connected to the ^{L 3} in any one of positions ^Y 52 ^{to Y 55.}

As a substituent of a substituted carbon atom, and when R ^{3 to} R ⁵ are substituted, a methyl group, a cyano group, a phenyl group, a pyridyl group, and the like are preferable from the viewpoint of not increasing the molecular weight. . Furthermore, a cyano group or a pyridyl group is more preferable because it has a high electron withdrawing property and a deep LUMO level facilitates the extraction of electrons from the photoelectric conversion layer to the anode and increases the photoelectric conversion efficiency. Moreover, as a preferable substituent of R < ³ > -R < ⁵ >, a phenyl group and a pyridyl group are preferable from the ease of a synthesis | combination.

Z ¹ is preferably an oxygen atom or sulfur atom having a small electron donating property from the viewpoint of not making the LUMO level shallow. In the case of a sulfur atom, the sulfur atom may be oxidized, may be an oxide or a dioxide, and the oxide is more preferable because the LUMO level can be deepened by using a dioxide.

Z ^{2 to} Z ⁴ are preferably NR ³ having a high electron withdrawing property, and form a benzimidazole ring in which Z ² and Z ⁴ are NR ³ and Z ³ is CR ⁴ R ⁵ from the viewpoint of synthesis. It is preferable.

  In each of the general formulas (7) to (11), as the number of nitrogen atoms increases, the electron withdrawing property increases and the LUMO level can be deepened, but the stability during sublimation also decreases accordingly. Therefore, considering the ease of synthesis and the stability during sublimation, the number of nitrogen atoms in general formula (7) is preferably 0 or 1, and the number of nitrogen atoms in general formula (8) is 2. In general formula (9), the number of nitrogen atoms is preferably 0 or 2. In general formula (10), the number of nitrogen atoms is preferably 0 to 2, and in general formula (11), It is preferable that the number of nitrogen atoms is 0-1.

  Although it does not specifically limit as a compound represented by General formula (1), Specifically, the following examples are given.

A known method can be used for the synthesis of the compound represented by the general formula (1). For example, there is a method of introducing A or B into the compound represented by L ¹ -L ² -L ³ . Examples of the method include a method using a coupling reaction of A and B with a compound represented by L ¹ -L ² -L ³ under a palladium catalyst or a nickel catalyst, or A and B under a palladium catalyst or a nickel catalyst. Examples thereof include, but are not limited to, a method using a coupling reaction between a boronic acid derivative of B and a halogenated compound represented by L ¹ -L ² -L ³ . In addition, boronic acid esters may be used in place of various boronic acids.

<Photoelectric conversion element>
1 to 4 show examples of the photoelectric conversion element of the present invention. FIG. 1 is an example of a photoelectric conversion element having a first electrode 10 and a second electrode 20 and at least one organic layer 15 interposed therebetween. The organic layer includes a photoelectric conversion layer that converts light into electrical energy. Hereinafter, a case where the first electrode 10 is a cathode and the second electrode 20 is an anode will be described as an example.

  The photoelectric conversion layer between the cathode and the anode in such a photoelectric conversion element may be composed of a single photoelectric conversion element material, but in order to obtain high photoelectric conversion efficiency, two or more kinds of photoelectric conversion layers are used. It is preferably composed of a conversion element material, and more preferably composed of two types of photoelectric conversion element materials. Furthermore, it is more preferable that one of the two types is an electron donating photoelectric conversion element material and the other is an electron accepting photoelectric conversion element material.

  Here, the electron accepting property indicates a property that electron affinity is high and electrons are easily received. On the contrary, the electron donating property shows the property of easily releasing electrons. When the photoelectric conversion layer is composed of an n-type organic semiconductor material having a high electron-accepting property and a p-type organic semiconductor material having a high electron-donating property, excitons generated in the photoelectric conversion layer by incident light return to the ground state. It can be efficiently separated into electrons and holes before. The separated electrons and holes flow through the n-type organic semiconductor material and the p-type organic semiconductor material to the anode and the cathode, respectively, so that high photoelectric conversion efficiency can be obtained.

  Further, in addition to the configuration consisting of only one photoelectric conversion layer, a charge blocking layer may be inserted between the cathode and the anode as shown in FIGS. The charge blocking layer is a layer having a function of blocking electrons or holes. When the charge blocking layer is inserted between the cathode and the photoelectric conversion layer, the charge blocking layer is inserted between the electron blocking layer 13 and the anode and the photoelectric conversion layer. If it is, it functions as the electron extraction layer 17. The photoelectric conversion element may contain only one kind of these layers, or may contain both.

  Furthermore, when the photoelectric conversion layer is composed of two or more types of photoelectric conversion element materials, the photoelectric conversion layer may be a single layer in which two or more types of photoelectric conversion element materials are mixed, or each one or more types of photoelectric conversion elements. A plurality of layers in which layers of element materials are stacked may be used. Furthermore, the structure by which the mixed layer and each single layer were mixed may be sufficient.

  The photoelectric conversion element of the present invention is a photoelectric conversion element in which at least one organic layer is present between the first electrode and the second electrode and converts light into electric energy, and the organic layer, preferably the organic layer The photoelectric conversion layer contained contains the compound represented by the general formula (1). Furthermore, since the compound represented by the general formula (1) is a compound having at least one electron-accepting nitrogen, the LUMO level is deep. Therefore, in the photoelectric conversion element in which the organic layer includes one electron extraction layer, the compound represented by the general formula (1) is included in the electron extraction layer, so that the electrons from the organic layer or the photoelectric conversion layer to the anode are included. It is preferable because it can be easily taken out and the photoelectric conversion efficiency is improved.

(Cathode and anode)
In the photoelectric conversion element of the present invention, the cathode and the anode have a role of allowing electrons and holes made in the element to flow and sufficient current to flow, and at least one of them is transparent to allow light to enter. Or it is desirable to be translucent. Usually, the cathode formed on the substrate is a transparent electrode.

The cathode may be a material that can efficiently extract holes from the photoelectric conversion layer and transparent to allow light to enter. Materials include conductive oxides such as tin oxide, indium oxide, indium tin oxide (ITO), indium zinc oxide (IZO), indium / gallium / zinc / oxygen (IGZO), or gold, silver, chromium, nickel, etc. Inorganic conductive materials such as copper iodide, copper iodide and copper sulfide, and conductive polymers such as polythiophene, polypyrrole and polyaniline are not particularly limited, but it is particularly preferable to use ITO glass or Nesa glass. These electrode materials may be used alone, or a plurality of materials may be laminated or mixed. The resistance of the transparent electrode is sufficient if a current generated by the element can flow sufficiently, and is preferably low from the viewpoint of photoelectric conversion efficiency of the element. For example, an ITO substrate having a resistance of 300Ω / □ or less functions as an element electrode, so that it is particularly preferable to use a low resistance product. The thickness of ITO can be arbitrarily selected according to the resistance value, but is usually used in a range of 50 to 300 nm. Further, soda lime glass, non-alkali glass or the like is used for the glass substrate, and the thickness of the glass substrate only needs to be sufficient to maintain the mechanical strength, so 0.5 mm or more is sufficient. The glass material is preferably alkali-free glass because it is better that there are fewer ions eluted from the glass, and soda lime glass with a barrier coating such as SiO ₂ can also be used. Furthermore, if the cathode functions stably, the substrate does not need to be made of glass. For example, the cathode may be formed on a plastic substrate. The ITO film forming method is not particularly limited, such as an electron beam method, a sputtering method, or a chemical reaction method.

  The anode is preferably a substance that can efficiently extract electrons from the photoelectric conversion layer, such as platinum, gold, silver, copper, iron, tin, zinc, aluminum, indium, chromium, lithium, sodium, potassium, calcium, magnesium, cesium, strontium, etc. Can be given. Lithium, sodium, potassium, calcium, magnesium, cesium or alloys containing these low work function metals are effective for improving the device characteristics by increasing the electron extraction efficiency. In addition, however, these low work function metals are generally unstable in the atmosphere. For example, a small amount of lithium, magnesium, or cesium is used in the hole blocking layer (1 nm or less as indicated by a film thickness gauge in vacuum deposition). A preferred example is a method in which an electrode having high stability is doped. An inorganic salt such as lithium fluoride can also be used. Furthermore, for electrode protection, metals such as platinum, gold, silver, copper, iron, tin, aluminum, indium, or alloys using these metals, and inorganic substances such as silica, titania, silicon nitride, polyvinyl alcohol, vinyl chloride, It is preferable to laminate a hydrocarbon polymer or the like. These electrodes are preferably produced by resistance heating, electron beam, sputtering, ion plating, coating or the like. When transparent electrodes are used for both the cathode and the anode as described in JP 2014-120616 A, a low work function conductive metal oxide such as IGZO is used for the anode. This is preferable because it leads to a reduction in dark current.

(Photoelectric conversion layer)
The photoelectric conversion layer is a layer in which a photoelectric conversion material is actually formed, and is formed by mixing a p-type organic semiconductor material and an n-type organic semiconductor material. At this time, the material may be single or plural. In the photoelectric conversion layer, after absorbing light and forming excitons, electrons and holes are separated by an n-type organic semiconductor material and a p-type organic semiconductor material, respectively. The separated electrons and holes flow to the both poles through the conduction level and the valence level, respectively, and generate electric energy.

  In addition to the compound represented by the general formula (1) described later, a material that has been known as a photoelectric conversion material has been used as the photoelectric conversion material constituting the photoelectric conversion layer. Since the absorption wavelength of the photoelectric conversion layer is determined by the light absorption wavelength region of the photoelectric conversion material, it is preferable to use a material having light absorption characteristics corresponding to the color to be used. For example, in the case of a green photoelectric conversion element, the photoelectric conversion layer is made of a material that absorbs light at 450 nm to 550 nm. In addition, when the photoelectric conversion layer is composed of two or more kinds of materials in order to obtain high photoelectric conversion efficiency as described above, the energy levels of the p-type organic semiconductor material and the n-type organic semiconductor material represent holes and electrons. The photoelectric conversion layer is formed of a material that can be efficiently separated and moved to the electrode side.

(P-type semiconductor layer)
The p-type organic semiconductor material may be any organic compound as long as it has a relatively small ionization potential, an electron donating property, and a hole transporting compound. Examples of p-type organic semiconductor materials include compounds having derivatives such as naphthalene, anthracene, phenanthrene, pyrene, chrysene, naphthacene, triphenylene, perylene, fluoranthene, fluorene, indene, derivatives thereof, cyclopentadiene derivatives, furan Derivatives, thiophene derivatives, pyrrole derivatives, benzofuran derivatives, benzothiophene derivatives, indole derivatives, pyrazoline derivatives, dibenzofuran derivatives, dibenzothiophene derivatives, carbazole derivatives, indolocarbazole derivatives, N, N′-dinaphthyl-N, N′-diphenyl- Aromatic amine derivatives such as 4,4′-diphenyl-1,1′-diamine, styrylamine derivatives, benzidine derivatives, porphyrin derivatives, phthalocyanine derivatives, quinaclide Derivatives thereof and the like.

  Examples of the polymer system include, but are not limited to, a polyphenylene vinylene derivative, a polyparaphenylene derivative, a polyfluorene derivative, a polyvinyl carbazole derivative, and a polythiophene derivative.

(N-type semiconductor layer)
The n-type organic semiconductor material may be any material as long as it has a high electron affinity and is an electron transporting compound. Examples of n-type organic semiconductor materials include compounds represented by the general formula (1), condensed polycyclic aromatic derivatives such as naphthalene and anthracene, and 4,4′-bis (diphenylethenyl) biphenyl. Styryl aromatic ring derivatives, tetraphenylbutadiene derivatives, coumarin derivatives, oxadiazole derivatives, pyrrolopyridine derivatives, perinone derivatives, pyrrolopyrrole derivatives, thiadiazolopyridine derivatives, pyrimidine derivatives, triazine derivatives, aromatic acetylene derivatives, aldazine derivatives, Pyrromethene derivatives, diketopyrrolo [3,4-c] pyrrole derivatives, azole derivatives such as imidazole, thiazole, thiadiazole, oxazole, oxadiazole, triazole and metal complexes thereof, quinone derivatives such as anthraquinone and diphenoquinone Examples thereof include various metal complexes such as conductors, phosphorus oxide derivatives, quinolinol complexes such as tris (8-quinolinolato) aluminum (III), benzoquinolinol complexes, hydroxyazole complexes, azomethine complexes, tropolone metal complexes, and flavonol metal complexes.

  Further, organic compounds having a nitro group, cyano group, halogen or trifluoromethyl group in the molecule, acid anhydride compounds such as quinone compounds, maleic acid anhydrides and phthalic acid anhydrides, fullerenes such as C60 and PCBM, and the like Although a fullerene derivative etc. are mentioned and can be used, it is not specifically limited.

(Charge blocking layer)
The charge blocking layer is a layer used to efficiently and stably take out electrons and holes photoelectrically converted in the photoelectric conversion layer from the electrode, and an electron blocking layer that blocks electrons and a hole that blocks holes. And a blocking layer. These may be comprised from the inorganic substance and may be comprised from the organic compound. Furthermore, you may consist of a mixed layer of an inorganic substance and an organic compound.

  The electron blocking layer is a layer for blocking electrons generated in the photoelectric conversion layer from flowing to the cathode side and recombining with holes. Depending on the type of material constituting each layer, this layer may be inserted. By doing so, recombination of holes and electrons is suppressed, and the photoelectric conversion efficiency is improved. Therefore, the electron blocking material preferably has an LUMO level higher in energy than the photoelectric conversion material. A compound that can efficiently block the movement of electrons from the photoelectric conversion layer is preferable. Specifically, N, N′-diphenyl-N, N′-bis (3-methylphenyl) -4,4′-diphenyl-1, Triphenylamines such as 1′-diamine, N, N′-bis (1-naphthyl) -N, N′-diphenyl-4,4′-diphenyl-1,1′-diamine, and bis (N-allylcarbazole) ) Or bis (N-alkylcarbazole) s, pyrazoline derivatives, stilbene compounds, distyryl derivatives, hydrazone compounds, oxadiazole derivatives, phthalocyanine derivatives, heterocyclic compounds typified by porphyrin derivatives, and the above monomers in polymer systems Polycarbonate, styrene derivatives, polyvinyl carbazole, polysilane, etc. Thin film is formed necessary manufacturing and can extract positive holes from the photoelectric conversion layer may be a further compound the hole can be transported. These electron blocking materials are used alone, but may be laminated or mixed with different electron blocking materials.

(Electronic extraction layer)
The electron extraction layer is a layer for efficiently transferring electrons generated in the photoelectric conversion layer to the anode side. Furthermore, it is a layer for preventing holes generated in the photoelectric conversion layer from flowing to the anode side and recombining with electrons. Depending on the type of material constituting each layer, insertion of this layer suppresses recombination of holes and electrons and improves photoelectric conversion efficiency. Therefore, the material used for the electron extraction layer is preferably a material having deeper LUMO and HOMO levels than the photoelectric conversion material. A compound that can efficiently extract electrons from the photoelectric conversion layer to the anode and further can efficiently block the movement of holes is preferable. This is because if the movement of holes can be efficiently blocked, the OFF current generated when a voltage is applied to an element not irradiated with light is reduced, and the dark current is reduced. Specifically, in addition to the compound represented by the general formula (1), quinolinol derivative metal complexes represented by 8-hydroxyquinoline aluminum, tropolone metal complexes, flavonol metal complexes, perylene derivatives, perinone derivatives, naphthalene derivatives, coumarin derivatives , Oxadiazole derivatives, aldazine derivatives, bisstyryl derivatives, pyrazine derivatives, oligopyridine derivatives such as bipyridine and terpyridine, phenanthroline derivatives, quinoline derivatives, and aromatic phosphorus oxide compounds. These materials can be used alone or in combination with different materials. In addition, two or more electron extraction layers each having different materials may be stacked.

  Since the compound represented by the general formula (1) is a compound having at least one electron-accepting nitrogen, the LUMO level and the HOMO level are deep. Therefore, it is preferable to use the compound represented by the general formula (1) in the electron extraction layer, because it facilitates electron extraction from the organic layer or the photoelectric conversion layer to the anode and improves the photoelectric conversion efficiency.

<Image sensor>
The photoelectric conversion element of this invention can be utilized suitably for an image sensor. An image sensor is a semiconductor element that converts an optical image into an electrical signal. In general, an image sensor includes the photoelectric conversion element that converts light into electric energy and a circuit that reads the electric energy into an electric signal. A plurality of photoelectric conversion elements can be arranged in a one-dimensional straight line or a two-dimensional plane depending on the application of the image sensor. Further, in the case of a monocolor image sensor, it may be composed of one type of photoelectric conversion element, but in the case of a color image sensor, it is composed of two or more types of photoelectric conversion elements, for example, photoelectric conversion that detects red light. It comprises an element, a photoelectric conversion element that detects green light, and a photoelectric conversion element that detects blue light. The photoelectric conversion elements of the respective colors have a stacked structure, that is, may be stacked in one pixel, or may be configured in a matrix structure side by side.

  In the case of a structure in which photoelectric conversion elements are stacked on one pixel, as shown in FIG. 5, a photoelectric conversion element 32 that detects green light, a photoelectric conversion element 33 that detects blue light, and a red light are detected. A three-layer structure in which the photoelectric conversion elements 31 are sequentially stacked may be used. As shown in FIG. 6, a photoelectric conversion element 32 that detects green light is arranged on the entire upper surface, the photoelectric conversion element 31 that detects red light, and blue light is detected. The photoelectric conversion element 33 to be formed may have a two-layer structure formed in a matrix structure. In this structure, a photoelectric conversion element that detects green light is arranged in a layer closest to incident light. The order of stacking the colors is not limited to this, and may be different from that shown in FIG. 5, but the uppermost photoelectric conversion element absorbs a specific color and transmits long-wavelength light and short-wavelength light other than the specific color. From the viewpoint of having a function as a color filter, a configuration in which a green photoelectric conversion element is arranged in the uppermost layer is preferable. Further, from the viewpoint of easy detection of a short wavelength, a configuration may be adopted in which a blue photoelectric conversion element is disposed in the uppermost layer.

  In the case of a matrix structure, an array such as a Bayer array, a honeycomb array, a stripe array, or a delta array can be selected. Moreover, an organic photoelectric conversion material is used for the photoelectric conversion element that detects green light, and the photoelectric conversion element that detects red light and the photoelectric conversion element that detects blue light are conventionally used inorganic photoelectric conversion materials. Or organic photoelectric conversion materials may be used in appropriate combination.

  As described above, since the photoelectric conversion element material of the present invention has a sharp absorption spectrum in the green region, the photoelectric conversion element can selectively absorb green light and transmit red light and blue light. it can. Therefore, in the case of the structure in which the photoelectric conversion elements are stacked vertically as shown in FIG. 7, the detection noise of red light and blue light can be extremely reduced in the green photoelectric conversion element, and red and blue photoelectric conversion is performed. Light can be detected with extremely high sensitivity in the element. Therefore, a photoelectric conversion element having excellent color separation can be provided. The order of stacking the respective colors is not limited to this, and may be different from that shown in FIG. 7. However, a configuration in which the green photoelectric conversion elements are arranged in the uppermost layer is preferable from the viewpoint of transmitting light other than green light. When the color selectivity of the blue photoelectric conversion element is excellent, the blue photoelectric conversion element may be arranged in the uppermost layer from the viewpoint of easy detection of a short wavelength.

  In addition, at least one of the photoelectric conversion element that detects red light, the photoelectric conversion element that detects green light, the photoelectric conversion element that detects blue light, and the photoelectric conversion element has a configuration including an electron extraction layer. May be. As an example, as shown in FIGS. 7 to 9, an electron extraction layer may be inserted between the color photoelectric conversion elements. The position of the electron extraction layer is not limited to this, and it may be arranged in the uppermost layer or the lowermost layer. 7 to 9, the electron extraction layer is provided only at one place, but it may be provided at two or more places. In addition, the order of stacking each color is not limited to this, and may be different from that shown in FIGS. 7 to 9. However, from the viewpoint of transmitting light other than green light, the configuration in which the green photoelectric conversion element is arranged in the uppermost layer is used. preferable. When the color selectivity of the blue photoelectric conversion element is excellent, the blue photoelectric conversion element may be arranged in the uppermost layer from the viewpoint of easy detection of a short wavelength.

  Furthermore, even if the photoelectric conversion element that detects red light, the photoelectric conversion element that detects green light, the photoelectric conversion element that detects blue light, and a configuration in which an electron extraction layer is provided for all of these photoelectric conversion elements, Good. As an example, as shown in FIG. 10, a configuration in which an electron extraction layer is disposed between all the red, green, and blue photoelectric conversion elements or in the lowermost layer is preferable from the viewpoint of reducing dark current. The position of the electron extraction layer is not limited to this, and it may be arranged in the uppermost layer or the lowermost layer. In addition, the order of stacking each color is not limited to this, and may be different from that shown in FIGS. 7 to 9. However, from the viewpoint of transmitting light other than green light, the configuration in which the green photoelectric conversion element is arranged in the uppermost layer is used. preferable. When the color selectivity of the blue photoelectric conversion element is excellent, the blue photoelectric conversion element may be arranged in the uppermost layer from the viewpoint of easy detection of a short wavelength.

  As described above, the image sensor of the present invention is composed of two or more types of photoelectric conversion elements, and at least one of them is preferably the above-described photoelectric conversion element. The two or more types of photoelectric conversion elements preferably have a laminated structure.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated, this invention is not limited by these examples. In addition, the evaluation method regarding structural analysis is shown below.

¹ H-NMR was measured with a deuterated chloroform solution using superconducting FTNMR EX-270 (manufactured by JEOL Ltd.).

  The absorption spectrum was measured by vapor deposition on a quartz substrate with a film thickness of 50 nm using a U-3200 spectrophotometer (manufactured by Hitachi, Ltd.). The absorption coefficient was calculated by Lambert-Beer Law.

Synthesis example 1
Synthesis of Compound [1] 2,4,6-Trichloropyrimidine (5.0 g), fluoranthene-3-boronic acid (13.4 g), bis (triphenylphosphine) palladium dichloride (382 mg), aqueous sodium carbonate solution (73 ml) Degassed acetonitrile (136 ml) was placed in a flask and purged with nitrogen, followed by heating under reflux for 2 hours. After cooling to room temperature, it was filtered and dried under reduced pressure to obtain a solid. The obtained solid was transferred to a flask, toluene (200 ml) was added, and the mixture was heated to reflux. After cooling to room temperature, filtration was performed to obtain 12.0 g of Intermediate A. Intermediate A has the following structure.

  Next, intermediate A (5.6 g), 4-pyridylphenylboronic acid (2.4 g), bis (dibenzylideneacetone) palladium (0) (250 mg), aqueous potassium phosphate (24 ml), tricyclohexylphosphine tetra Fluoroborate (192 mg) was placed in a flask, purged with nitrogen, and heated to reflux for 3 hours. After cooling to room temperature, it was filtered and dried under reduced pressure to obtain a solid. The obtained solid was transferred to a flask, pyridine (400 ml) was added, and the mixture was heated to reflux. After the temperature was lowered, activated carbon (6.9 g) was added, stirred for 1 hour, and filtered through a silica pad. The filtrate was evaporated, and the resulting solid was washed with methanol, filtered again, and dried under reduced pressure to obtain compound [1].

  The results of H-NMR analysis of the obtained solid are as follows, and it was confirmed that the solid obtained above was compound [1].

Compound [1]: H-NMR (CDCl ₃ (d = ppm)) δ 7.42-7.46 (m, 4H), 7.62-7.64 (m, 2H), 7.73-8. 19 (m, 15H), 8.59-8.62 (m, 2H), 8.70-8.73 (m, 2H), 8.87-8.90 (m, 2H).

Compound [1] was used as a photoelectric conversion element material after sublimation purification at about 350 ° C. under a pressure of 1 × 10 ⁻³ Pa using an oil diffusion pump.

Synthesis example 2
Synthesis of Compound [2] Intermediate A (2.0 g), (4- (naphthalen-1-yl) phenyl) boronic acid (1.1 g), bis (triphenylphosphine) palladium dichloride (55 mg), aqueous potassium carbonate solution (9 ml) and a tetrahydrofuran / toluene mixed solution (19 ml) were placed in a flask, purged with nitrogen, and heated to reflux for 3 hours. After cooling to room temperature, water was added and the mixture was filtered and dried under reduced pressure to obtain a solid. The obtained solid was transferred to a flask, pyridine (100 ml) was added, and the mixture was heated to reflux. After the temperature was lowered, activated carbon (312 mg) was added, stirred for 1 hour, and filtered through a silica pad. The filtrate was evaporated and the resulting solid was washed with methanol, filtered again and dried under reduced pressure to give a solid. The obtained solid was recrystallized with ortho-xylene (60 ml), filtered and dried under reduced pressure to obtain compound [2].

  The results of H-NMR analysis of the obtained solid are as follows, and it was confirmed that the solid obtained above was compound [2].

Compound [2]: H-NMR (CDCl ₃ (d = ppm)) δ 7.45-7.54 (m, 7H), 7.70-7.78 (m, 4H), 7.92-8. 21 (m, 15H), 8.64-8.67 (d, 2H, J = 7.83 Hz), 8.88-8.91 (d, 2H, J = 8.10 Hz).

Compound [2] was used as a photoelectric conversion element material after sublimation purification at about 350 ° C. under a pressure of 1 × 10 ⁻³ Pa using an oil diffusion pump.

Example 1
A photoelectric conversion element using the compound [1] was produced as follows. A glass substrate on which an ITO transparent conductive film was deposited to a thickness of 150 nm (Asahi Glass Co., Ltd., 15Ω / □, electron beam evaporated product) was cut into 30 × 40 mm and etched. The obtained substrate was ultrasonically washed with acetone and “Semicoclean (registered trademark) 56” (manufactured by Furuuchi Chemical Co., Ltd.) for 15 minutes, respectively, and then washed with ultrapure water. Subsequently, it was ultrasonically cleaned with isopropyl alcohol for 15 minutes and then immersed in hot methanol for 15 minutes and dried. This substrate was subjected to UV-ozone treatment for 1 hour immediately before producing the device, placed in a vacuum deposition apparatus, and evacuated until the degree of vacuum in the apparatus became 5 × 10 ⁻⁵ Pa or less. PEDOT: PSS was deposited as an electron blocking layer by a resistance heating method to a thickness of 30 nm. Next, Compound D-1 and Compound A-1 were co-deposited at a deposition rate ratio of 1: 1 as a photoelectric conversion layer. Next, 20 nm of compound [1] was vapor-deposited as an electron extraction layer. Aluminum was deposited to a thickness of 100 nm to form a cathode, and a 5 × 5 mm square element was produced. The film thickness referred to here is a crystal oscillation type film thickness monitor display value.

The prepared deposited film was sealed in the glove box, the film after 48 hours was visually observed, and the state of the film heated at 100 ° C. for 3.5 hours with a hot plate was visually observed. There was no change in the condition. Further, the ON current and OFF current after heating under the above conditions were measured. The ON current is a current value when -3V is applied to the element by irradiating light from a white LED light source (35000 lux) from the ITO substrate, and the OFF current is when no light is irradiated. It is a current value when -3V is applied to the element. As a result, the ON current was 3.3 × 10 ⁻⁴ mA / cm ² , and the OFF current was 3.8 × 10 ⁻⁸ mA / cm ² . Further, the photoelectric conversion efficiency when -3 V was applied before and after heating under the above conditions was 27% before heating and 27% after heating. PEDOT: PSS, D-1, and A-1 are the compounds shown below.

Examples 2-6
A photoelectric conversion element was prepared and evaluated in the same manner as in Example 1 except that the compounds described in Table 1 were used for the electron extraction layer. The results are shown in Table 1. Compounds 3 to 6 are compounds shown below.

Comparative Examples 1-7
A photoelectric conversion element was prepared and evaluated in the same manner as in Example 1 except that the compounds described in Table 1 were used for the electron extraction layer. The results are shown in Table 1. HB-1 to HB-6 are the compounds shown below.

DESCRIPTION OF SYMBOLS 10 1st electrode 13 Electron blocking layer 15 Organic layer 17 Electron extraction layer 20 2nd electrode 31 Photoelectric conversion element 32 which detects red light Photoelectric conversion element 33 which detects green light Photoelectric conversion element which detects blue light

Claims (15)

There is at least one organic layer between the first electrode and the second electrode, and the photoelectric conversion element converts light energy into electric energy. The organic layer has a molecular weight of 350 or more, and has the following general formula ( A photoelectric conversion device comprising the compound represented by 1).

(In the formula, A and B are a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group. However, A and B are different groups. L ¹ and L ³ are single bonds, substituted or unsubstituted. A substituted arylene group or a substituted or unsubstituted heteroarylene group, where n is an integer of 1 to 3, provided that when n = 1, at least one of A and B is substituted or unsubstituted. A substituted condensed aromatic hydrocarbon group having 9 or more nuclear carbon atoms, or a substituted or unsubstituted condensed aromatic heterocyclic group having 9 or more nuclear carbon atoms is selected. ² is a substituted or unsubstituted heteroarylene group having at least one electron-accepting nitrogen. The photoelectric conversion element according to claim 1, wherein at least one of A and B in the general formula (1) is a substituted or unsubstituted heteroaryl group. The photoelectric conversion element according to claim 1, wherein L ^{2 in the} general formula (1) is a group represented by any one of the following general formulas (2) to (6).

(In the formula, X ^{1 to} X ⁴⁶ represent CH, a substituted carbon atom, or a nitrogen atom. Provided that at least one of X ^{1 to} X ⁶ , at least one of X ^{7 to} X ¹⁴ , X ^{15 to} X at least one of ^24, at least one of X 25 ^{to X 34,} at least one of X 35 ^{to X 46} are each nitrogen atom.
In the general formula (2) and ^{L 1} at any one of positions ^X 1 to X ^6, respectively connect with ^{L 2} at one of the positions of the other.
In the general formula (3) ^X 7 and ^{L 1} at any one of positions ^{to X 14,} respectively connect with ^{L 2} at one position one of the other.
In the general formula (4) ^X 15 and ^{L 1} at any one of positions ^{to X 24,} respectively connect with ^{L 2} at one position one of the other.
In the general formula (5) and ^{L 1} at any one of positions ^X 25 ^{to X 34,} respectively connect with ^{L 2} at one of the positions of the other.
In the general formula (6) and ^{L 1} at any one of positions ^X 35 ^{to X 46,} respectively connect with ^{L 2} at one of the positions of the other. ) The photoelectric conversion device according to claim 1, wherein L ^{2 in the} general formula (1) is a substituted or unsubstituted pyrimidinylene group, a substituted or unsubstituted triazinylene group, or a substituted or unsubstituted quinazolinylene group. . The photoelectric conversion element according to claim 1, wherein L ^{2 in the} general formula (1) is a substituted or unsubstituted pyrimidinylene group. The photoelectric conversion element according to claim 1, wherein A in the general formula (1) is represented by a heteroaryl group containing a nitrogen atom. The photoelectric conversion element according to claim 1, wherein B in the general formula (1) is a group represented by any one of the following general formulas (7) to (12).

(In the formula, Y ^{1 to} Y ⁵⁵ each independently represent CH, a substituted carbon atom or a nitrogen atom. The adjacent Y ⁱ (i = 1 to 55) may be condensed to form a ring. Z ^{1 to} Z ⁴ are each independently NR ³ , CR ⁴ R ⁵ , O or S. R ^{3 to} R ⁵ are each independently a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group. .
However, in the general formula (7) connects the ^{L 3} in any one of positions ^Y 1 ^{to Y 10.}
In the general formula (8) is connected to the ^{L 3} in any one of positions ^Y 11 ^{to Y 21.}
In the general formula (9) connects the ^{L 3} in any one of positions ^Y 22 ^{to Y 31.}
In the general formula (10) is connected to the ^{L 3} in any one of positions ^Y 32 ^{to Y 43.}
Of ^Y 44 ^{to Y 51} in the general formula (11), or is connected to the ^{L 3} in any one position of ^{R 3.}
In the general formula (12) is connected to the ^{L 3} in any one of positions ^Y 52 ^{to Y 55.} ) N of general formula (1) is 2, The photoelectric conversion element in any one of Claims 1-7. The photoelectric conversion element according to claim 1, wherein the organic layer includes a photoelectric conversion layer, and the photoelectric conversion layer contains the compound represented by the general formula (1). The organic layer includes at least one photoelectric conversion layer and one electron extraction layer between the first electrode and the second electrode, and the electron extraction layer contains the compound represented by the general formula (1). Item 10. The photoelectric conversion element according to any one of Items 1 to 9. The image sensor containing the photoelectric conversion element in any one of Claims 1-10. The image sensor according to claim 11, comprising two or more types of photoelectric conversion elements, one of which is the photoelectric conversion element according to claim 1. The image sensor according to claim 12, wherein the two or more types of photoelectric conversion elements have a laminated structure, and one type of the photoelectric conversion elements is the photoelectric conversion element according to claim 1. The photoelectric conversion element for detecting red light, the photoelectric conversion element for detecting green light, the photoelectric conversion element for detecting blue light, and at least one of these photoelectric conversion elements is provided with an electron extraction layer. Image sensor. The photoelectric conversion element for detecting red light, the photoelectric conversion element for detecting green light, the photoelectric conversion element for detecting blue light, and an electron extraction layer for all of the photoelectric conversion elements. The image sensor according to Crab.

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