JP2021015963A - Photoelectric conversion element material and uses thereof - Google Patents

Abstract

To provide: a photoelectric conversion element material that can be a material for a block layer excellent in a hole leak prevention property, an electronic transport property, heat resistance to a process temperature, transparency to visible light, and the like; and various electronic devices such as a photoelectric conversion element comprising the photoelectric conversion element material.SOLUTION: A photoelectric conversion element material contains a compound represented by the formula (1) in the figure. (In the formula (1), R1 to R4 each independently represent a hydrogen atom, aromatic group, heterocyclic group, aliphatic hydrocarbon group, or halogen atom; and X represents an oxygen atom or sulfur atom.)SELECTED DRAWING: None

Description

The present invention relates to a material for a photoelectric conversion element containing an organic compound having a specific structure and a photoelectric conversion element containing the material for the photoelectric conversion element.

In recent years, there has been increasing interest in organic electronic devices, which are characterized by having flexibility, being able to increase the area, and being able to be manufactured by an inexpensive and high-speed printing method. Typical examples of organic electronic devices include organic EL elements, organic solar cell elements, organic photoelectric conversion elements, organic transistor elements, etc. Among these, organic EL elements are portable mainly for next-generation display applications. It is expected to be applied to telephone displays and TVs, and development aimed at further higher functionality is continuing. Organic solar cell elements and the like have been researched and developed as flexible and inexpensive energy sources, and organic transistor elements have been researched and developed for the purpose of application to flexible displays and inexpensive ICs.

In the field of organic electronic devices, it is very important to develop excellent materials that make up the device, and therefore many studies and developments are still being vigorously carried out in the field of each material.

In recent years, several groups have also reported on organic photoelectric conversion elements, which are expected to be applied to next-generation solar cells and optical sensors. For example, Patent Document 1 shows an example in which a quinacridone derivative or a quinazoline derivative is used for a photoelectric conversion element, and Patent Document 2 shows an example in which a diketopyrrolopyrrole derivative is used.
In the image sensor, a hole block layer or an electron block layer is inserted between the photoelectric conversion unit and the electrode unit for the purpose of reducing the leakage current from the photoelectric conversion unit in the dark in order to obtain the S / N ratio. The method is commonly used.

The hole block layer and the electron block layer, which are generally widely used in the field of organic electronic devices, are arranged at the interface between an electrode or a conductive film and another film in the constituent film of the device, and each hole is formed. Alternatively, it plays a role of controlling the reverse movement of electrons and adjusting the leakage of unnecessary holes or electrons, and is selected and used in consideration of heat resistance, transmission wavelength, film formation method, etc. depending on the application of the device. Is something that can be done.
Patent Document 3 shows an example in which fullerene is used as the hole block layer, and Patent Document 4 shows 1,4,5,8-naphthalene-tetracarboxylic dianhydride as the hole block layer. An example using NTCDA) is shown. However, the required performance of materials for photoelectric conversion elements is particularly high, and the conventional hole block layer and electron block layer are sufficient in terms of leakage current prevention characteristics, heat resistance to process temperature, visible light transparency, and the like. It cannot be said that it has performance, and it has not been used commercially.

Japanese Patent No. 4972288 Japanese Patent No. 5022573 Special Table 2013-544440 Japanese Patent Publication No. 2014-506736

The present invention has been made in view of such a situation, and is a photoelectric material which is a material of a block layer having excellent hole leakage prevention characteristics, electron transport characteristics, heat resistance to device fabrication process temperature, visible light transparency, and the like. It is an object of the present invention to provide various electronic devices including a material for a conversion element and a photoelectric conversion element including the material for the photoelectric conversion element.

As a result of diligent efforts to solve the above problems, the present inventor has found that the above problems can be solved by applying a material for a photoelectric conversion element containing a compound having a specific structure to the photoelectric conversion element. It came to be completed.
That is, the present invention is as follows.
[1] The following formula (1)

(In the formula (1), R ^{1 to} R ⁴ independently represent a hydrogen atom, an aromatic group, a heterocyclic group, an aliphatic hydrocarbon group or a halogen atom. X represents an oxygen atom or a sulfur atom.) A material for a photoelectric conversion element containing a compound represented by.
[2] The material for a photoelectric conversion element according to the previous item [1], wherein X is an oxygen atom.
[3] R ¹ and R ² are hydrogen atoms, one of R ³ and R ⁴ is a hydrogen atom, an aromatic group, a heterocyclic group, an aliphatic hydrocarbon group or a halogen atom, and the other is an aromatic group. The material for a photoelectric conversion element according to the above item [1] or [2], which is a heterocyclic group, an aliphatic hydrocarbon group or a halogen atom.
[4] An organic thin film containing the material for a photoelectric conversion element according to any one of the above items [1] to [3].
[5] A photoelectric conversion element containing the organic thin film according to the previous item [4].
[6] The photoelectric conversion element according to the previous item [5], wherein the organic thin film is a hole block layer.
[7] The photoelectric conversion element according to the previous item [5] or [6], which is a light emitting element.
[8] An image pickup device in which the photoelectric conversion elements according to any one of the above items [5] to [7] are arranged in a plurality of arrays.
[9] An optical sensor including the photoelectric conversion element according to the previous item [5] or the image pickup element according to the previous item [8].
[10] The following formula (2)

(In formula (2), one of R ⁵ and R ⁶ represents a hydrogen atom, an aromatic group, a heterocyclic group, an aliphatic hydrocarbon group or a halogen atom, and the other represents an aromatic group, a heterocyclic group or an aliphatic group. A compound represented by a hydrocarbon group or a halogen atom. X represents an oxygen atom or a sulfur atom).
[11] The compound according to the preceding item [10], wherein X is an oxygen atom.

The material for a photoelectric conversion element of the present invention containing a compound having a specific structure exhibits hole or electron leakage prevention and transportability, and has heat resistance and visible light transparency that can withstand the device manufacturing process. It is possible to provide a photoelectric conversion element exhibiting excellent characteristics.

FIG. 1 shows a cross-sectional view illustrating an embodiment of the photoelectric conversion element of the present invention. FIG. 2 shows a schematic cross-sectional view showing an example of a layer configuration of an organic electroluminescence device. FIG. 3 shows dark current-voltage graphs of the photoelectric conversion elements obtained in Examples 3 to 5 and Comparative Examples 1 to 3. FIG. 4 shows the absorption spectrum of the thin film of the synthetic example compound.

The contents of the present invention will be described in detail. The description of the constituent elements described below is based on typical embodiments and specific examples of the present invention, but the present invention is not limited to such embodiments and specific examples.

[Compound of formula (1)]
The material for a photoelectric conversion element of the present invention contains a compound represented by the following formula (1).

In the formula (1), R ^{1 to} R ⁴ independently represent a hydrogen atom, an aromatic group, a heterocyclic group, an aliphatic hydrocarbon group or a halogen atom, respectively.
The aromatic group represented by R ^{1 to} R ⁴ of the formula (1) is a residue obtained by removing one hydrogen atom from the aromatic ring of the aromatic compound.
Examples of the aromatic group represented by R ^{1 to} R ⁴ of the formula (1) include a phenyl group, a biphenyl group, a turphenyl group, a tolyl group, an indenyl group, a naphthyl group, an anthryl group, a fluorenyl group, a pyrenyl group, a phenanthnyl group and the like. Examples thereof include a methyl group, and a phenyl group, a biphenyl group, a turphenyl group, a naphthyl group or an anthyl group is preferable, and a phenyl group, a biphenyl group, a terphenyl group or a naphthyl group is more preferable.

The heterocyclic group represented by R ^{1 to} R ⁴ of the formula (1) is a residue obtained by removing one hydrogen atom from the heterocycle of the heterocyclic compound.
Examples of the heterocyclic group represented by R ^{1 to} R ⁴ of the formula (1) include a furanyl group, a thienyl group, a thienotienyl group, a pyrrolyl group, an imidazolyl group, an N-methylimidazolyl group, a thiazolyl group, an oxazolyl group, a pyridyl group and a pyrazil group. Group, pyrimidyl group, quinolyl group, indolyl group, benzopyrazyl group, benzopyrimidyl group, benzothienyl group, naphthophenyl group, benzofuranyl group, benzothiazolyl group, pyridinothiazolyl group, benzoimidazolyl group, pyridinoimidazolyl group, N-methylbenzoimidazolyl group , Pyridino-N-methylimidazolyl group, benzoxazolyl group, pyridinooxazolyl group, benzothiadiazolyl group, pyridinothiazolyl group, benzoxaziazolyl group, pyridinooxadiazolyl group, carbazolyl group , Phenoxazinyl group, phenothiazinyl group and the like, preferably a furanyl group, a thienyl group, a thienothienyl group, a benzothienyl group, a benzofuranyl group, a pyridyl group or a pyrazil group, and more preferably a flanyl group, a thienyl group, a pyridyl group or a pyrazil group. ..

The aliphatic hydrocarbon group represented by R ^{1 to} R ⁴ of the formula (1) is a residue obtained by removing one hydrogen atom from the aliphatic hydrocarbon compound, and can be either linear, branched or cyclic. Is not limited, and may contain unsaturated bonds.
Examples of the aliphatic hydrocarbon group represented by R ^{1 to} R ⁴ of the formula (1) include a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, an iso-butyl group and a t-butyl group. , N-pentyl group, iso-pentyl group, t-pentyl group, sec-pentyl group, cyclopentyl group, n-hexyl group, iso-hexyl group, cyclohexyl group, n-heptyl group, sec-heptyl group, n-octyl It is preferably an alkyl group having 1 to 20 carbon atoms such as a group, a vinyl group, an ethynyl group, a propenyl group, a propagyl group, butenyl, a pentenyl group and a hexenyl group, and an alkyl group having 1 to 12 carbon atoms. Is more preferable, and an alkyl group having 1 to 6 carbon atoms is further preferable.

Examples of the halogen atom represented by R ^{1 to} R ⁴ of the formula (1) include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, and a fluorine atom, a chlorine atom or a bromine atom is preferable.

The aromatic group, heterocyclic group and aliphatic hydrocarbon group represented by R ^{1 to} R ⁴ of the formula (1) may have a substituent. Hereinafter, the substituent having an aromatic group, a heterocyclic group and an aliphatic hydrocarbon group represented by R ^{1 to} R ⁴ of the formula (1) is simply referred to as "a substituent having R ^{1 to} R ⁴ of the formula (1)". Describe.
The substituents of R ^{1 to} R ⁴ of the formula (1) may be either an electron-attracting substituent or an electron-donating substituent, but an electron-attracting substituent is preferable.
As the electron-attracting substituent, a halogen atom, a perfluoroalkyl group, an acyl group, a benzoyl group, a carboxyl group, an alkoxycarbonyl group, a nitro group, a cyano group or an isocyano group is preferable, and a halogen atom, a perfluoroalkyl group, etc. An acyl group, an alkoxycarbonyl group or a cyano group is more preferable, and a halogen atom, a perfluoroalkyl group or a cyano group is further preferable.
As the electron-donating substituent, an alkyl group, an alkoxy group, a phenoxy group, an aromatic group, a hydroxyl group, a mercapto group, an alkyl-substituted amino group, an aryl-substituted amino group or an unsubstituted amino group (NH ₂ group) are preferable, An alkyl group, an alkoxy group, an aromatic group or an aryl substituted amino group is more preferable, and an alkyl group or an alkoxy group is further preferable.

Examples of the halogen atom as R ¹ to substituent R ⁴ has the formula (1), include the same as the halogen atom represented by R ¹ to R ⁴ of formula (1), also the same as mentioned preferred ..

The perfluoroalkyl group as the substituent of R ^{1 to} R ⁴ of the formula (1) is a substituent in which all the hydrogen atoms of the alkyl group are replaced with fluorine atoms, and is an alkyl group that can be a perfluoroalkyl group. Specific examples of the above include methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, iso-butyl group, t-butyl group, n-pentyl group, iso-pentyl group and t-pentyl. Group, sec-pentyl group, n-hexyl group, iso-hexyl group, n-heptyl group, sec-heptyl group, n-octyl group, n-nonyl group, sec-nonyl group, n-decyl group, n-undecyl Number of carbon atoms such as group, n-dodecyl group, n-tridecyl group, n-tetradecyl group, n-pentadecyl group, n-hexadecyl group, n-heptadecyl group, n-octadecyl group, n-nonadecil group and n-eicosyl group. Examples include 1 to 20 alkyl groups.
As the perfluoroalkyl group as the substituent contained in R ^{1 to} R ⁴ of the formula (1), a perfluoroalkyl group having 1 to 20 carbon atoms is preferable, and a perfluoroalkyl group having 1 to 12 carbon atoms is more preferable. A perfluoroalkyl group having 1 to 6 carbon atoms is more preferable, and a perfluoroalkyl group having 1 to 4 carbon atoms is particularly preferable.

The acyl group as a substituent of R ^{1 to} R ⁴ of the formula (1) is a substituent in which a carbonyl group and an alkyl group are bonded, and a specific example of the alkyl group of the acyl group is the formula (1). Examples thereof include the same alkyl groups described in the section of perfluoroalkyl groups as substituents of R ^{1 to} R ⁴ of the above.
As the acyl group as the substituent of R ^{1 to} R ⁴ of the formula (1), an acyl group having an alkyl group having 1 to 20 carbon atoms is preferable, and an acyl group having an alkyl group having 1 to 12 carbon atoms is more preferable. Preferably, an acyl group having an alkyl group having 1 to 6 carbon atoms is more preferable, and an acyl group having an alkyl group having 1 to 4 carbon atoms is particularly preferable.

The alkoxycarbonyl group as a substituent contained in R ^{1 to} R ⁴ of the formula (1) is a substituent in which a carbonyl group and an alkoxy group are bonded, and as a specific example of the alkyl group in the alkoxy group possessed by the alkoxycarbonyl group. Is the same as the alkyl group described in the section of the perfluoroalkyl group as the substituent contained in R ^{1 to} R ⁴ of the formula (1).
As the alkoxycarbonyl group as the substituent contained in R ^{1 to} R ⁴ of the formula (1), an alkoxycarbonyl group having an alkoxy group having 1 to 20 carbon atoms is preferable, and an alkoxycarbonyl group having an alkoxy group having 1 to 12 carbon atoms is preferable. The group is more preferable, the alkoxycarbonyl group having an alkoxy group having 1 to 6 carbon atoms is further preferable, and the alkoxycarbonyl group having an alkoxy group having 1 to 4 carbon atoms is particularly preferable.

The alkyl group as the substituent of R ^{1 to} R ⁴ of the formula (1) is the same as the alkyl group described in the section of the perfluoroalkyl group as the substituent of R ^{1 to} R ⁴ of the formula (1). Things can be mentioned.
As the alkyl group as the substituent contained in R ^{1 to} R ⁴ of the formula (1), an alkyl group having 1 to 20 carbon atoms is preferable, an alkyl group having 1 to 12 carbon atoms is more preferable, and an alkyl group having 1 to 6 carbon atoms is more preferable. Alkyl groups are more preferable, and alkyl groups having 1 to 4 carbon atoms are particularly preferable.

The alkoxy group as the substituent of R ^{1 to} R ⁴ of the formula (1) is a substituent in which an oxygen atom and an alkyl group are bonded, and a specific example of the alkyl group of the alkoxy group is the formula (1). Examples thereof include the same alkyl groups described in the section of perfluoroalkyl groups as substituents of R ^{1 to} R ⁴ of the above.
As the alkoxy group as the substituent contained in R ^{1 to} R ⁴ of the formula (1), an alkoxy group having 1 to 20 carbon atoms is preferable, an alkoxy group having 1 to 12 carbon atoms is more preferable, and an alkoxy group having 1 to 6 carbon atoms is more preferable. An alkoxy group is more preferable, and an alkoxy group having 1 to 4 carbon atoms is particularly preferable.

The phenoxy group as the substituent of R ^{1 to} R ⁴ of the formula (1) is a substituent in which an oxygen atom and an aromatic group are bonded, and a specific example of the aromatic group of the phenoxy group is the formula (1). The same aromatic groups represented by R ^{1 to} R ^{4 in} 1) can be mentioned, and the same preferred ones can be mentioned.

Specific examples of the aromatic group as R ¹ to substituent R ⁴ has the formula (1) may include the same as the aromatic group R ¹ to R ⁴ represents the formula (1), preferred ones also The same can be mentioned.

The alkyl-substituted amino group as a substituent contained in R ^{1 to} R ⁴ of the formula (1) is not limited to either a monoalkyl-substituted amino group or a dialkyl-substituted amino group, and the alkyl group in these alkyl-substituted amino groups , The same alkyl group as described in the section of perfluoroalkyl group as a substituent possessed by R ^{1 to} R ⁴ of the formula (1) can be mentioned.
As the alkyl-substituted amino group as the substituent of R ^{1 to} R ⁴ of the formula (1), a mono or dialkyl-substituted amino group in which each of the alkyl groups has 1 to 6 carbon atoms is preferable, and each of the alkyl groups is carbon. More preferably, a mono or dialkyl substituted amino group having the number 1 to 4 is preferable.

The aryl-substituted amino group as the substituent contained in R ^{1 to} R ⁴ of the formula (1) is not limited to either a monoaryl-substituted amino group or a diaryl-substituted amino group, and the aryl group in these aryl-substituted amino groups is , The same aromatic group represented by R ^{1 to} R ⁴ of the formula (1), or the same heteroaromatic group described in the section of the heterocyclic group represented by R ^{1 to} R ⁴ of the formula (1). The same is preferable.

X in the formula (1) represents an oxygen atom or a sulfur atom, and an oxygen atom is preferable.

As the compound represented by the formula (1), R ¹ and R ² are hydrogen atoms, and one of R ³ and R ⁴ is a hydrogen atom, an aromatic group, a heterocyclic group, an aliphatic hydrocarbon group or a halogen atom. A compound in which the other is an aromatic group, a heterocyclic group, an aliphatic hydrocarbon group or a halogen atom, that is, a compound represented by the following formula (2) is preferable.

In formula (2), one of R ⁵ and R ⁶ represents a hydrogen atom, an aromatic group, a heterocyclic group, an aliphatic hydrocarbon group or a halogen atom, and the other represents an aromatic group, a heterocyclic group or an aliphatic hydrocarbon. Represents a hydrogen group or a halogen atom. X represents an oxygen atom or a sulfur atom.
Specific examples of the aromatic group, heterocyclic group, aliphatic hydrocarbon group and halogen atom represented by R ⁵ and R ⁶ of the formula (2) include the aromatic group represented by R ^{1 to} R ⁴ of the formula (1). The same ones as the heterocyclic group, the aliphatic hydrocarbon group and the halogen atom can be mentioned, and the same ones can be mentioned as preferable ones.

The compound represented by the formula (2) can be synthesized, for example, by the method shown in the following scheme, using the compound represented by the formula (1-1) as a starting material. Specifically, the compound represented by the formula (1-1) is subjected to a halogenation reaction accompanied by ring opening of the dicarboxylic acid anhydride and a subsequent alkylation reaction, so that the compound is represented by the formula (M-1). Synthesize the tetraester compound to be produced. Then, the compound represented by the formula (M-1) is subjected to a cross-coupling reaction to introduce a substituent to obtain an intermediate represented by the formula (M-2). Finally, a cyclization reaction is carried out to obtain a desired compound represented by the formula (2).

In the above formula (M-1), X represents a halogen atom and Me represents a methyl group.
In the formula (M-2), ^{R 5} and ^{R 6} are the same meaning as ^{R 5} and ^{R 6} in Formula (2), Me represents respectively a methyl group.

The method for purifying the compound represented by the formula (1) is not particularly limited, and known methods such as recrystallization, column chromatography, and vacuum sublimation purification can be adopted. Moreover, these methods can be combined as needed.

Specific examples of the compound represented by the formula (1) will be illustrated below, but the compound represented by the formula (1) contained in the material for a photoelectric conversion element of the present invention is limited to these specific examples. is not it.
In the present specification, "Hx" in the structural formula means an n-hexyl group, "Ph" means a phenyl group, and "Me" means a methyl group.

The content of the compound represented by the formula (1) in the material for a photoelectric conversion element of the present invention is not particularly limited as long as the performance required in the application using the material for a photoelectric conversion element is exhibited, but is usually 50. It is mass% or more, preferably 80% by mass or more, more preferably 90% by mass or more, still more preferably 95% by mass or more.
The material for a photoelectric conversion element of the present invention may be used in combination with a compound other than the compound represented by the formula (1) (for example, a material for a photoelectric conversion element other than the compound represented by the formula (1)) or an additive. You may. The compounds and additives that can be used in combination are not particularly limited as long as the performance required in the application using the material for the photoelectric conversion element is exhibited.

[Organic thin film]
The organic thin film of the present invention contains the material for a photoelectric conversion element of the present invention.
The organic thin film of the present invention can be produced by a general dry film forming method or wet film forming method. Specifically, it is a vacuum process such as resistance heating vapor deposition, electron beam deposition, sputtering and molecular lamination method, solution process casting, spin coating, dip coating, blade coating, wire bar coating and spray coating, and inkjet printing. , Screen printing, offset printing, printing methods such as letterpress printing, and soft lithography methods such as microcontact printing.
Generally, it is desirable that the material for a photoelectric conversion element can be used in a process in which a compound is coated in a solution state from the viewpoint of ease of processing, but in the case of an organic electronics device in which an organic film is laminated, a coating solution is used. Is not suitable because it may attack the organic film in the lower layer.

In order to realize such a multi-layer laminated structure, it is appropriate to use a material that can be used in a dry film deposition method, for example, a vapor deposition process such as resistance heating vapor deposition. Therefore, a material for a photoelectric conversion element that can be vapor-deposited is preferable.

A method in which a plurality of the above methods are combined may be adopted for film formation of each layer. The thickness of each layer cannot be limited because it depends on the resistance value and charge mobility of each substance, but is usually in the range of 0.5 to 5,000 nm, preferably in the range of 1 to 1,000 nm. , More preferably in the range of 5 to 500 nm.

[Organic electronics device]
The photoelectric conversion element of the present invention includes the organic thin film of the present invention. A photoelectric conversion element is an element in which a photoelectric conversion unit (film) is arranged between a pair of electrode films facing each other, and light is incident on the photoelectric conversion unit from above the electrode films. The photoelectric conversion unit generates electrons and holes in response to the incident light, and a semiconductor reads out a signal corresponding to the electric charge to indicate the amount of incident light according to the absorption wavelength of the photoelectric conversion film unit. Is. A transistor for reading may be connected to the electrode film on the side where light is not incident. When a large number of photoelectric conversion elements are arranged in an array, it is an image sensor because it shows incident position information in addition to the amount of incident light. Further, when the photoelectric conversion element arranged closer to the light source does not shield (transmit) the absorption wavelength of the photoelectric conversion element arranged behind the photoelectric conversion element when viewed from the light source side, a plurality of photoelectric conversion elements are laminated. You may use it.

The photoelectric conversion element of the present invention uses a material for a photoelectric conversion element containing a compound represented by the above formula (1) as a constituent material of the photoelectric conversion unit.
The photoelectric conversion unit is one or a plurality of types selected from the group consisting of a photoelectric conversion layer, an electron transport layer, a hole transport layer, an electron block layer, a hole block layer, a crystallization prevention layer, an interlayer contact improvement layer, and the like. It is often composed of an organic thin film layer other than the photoelectric conversion layer. In particular, the electron transport layer, the hole transport layer, the electron block layer and the hole block layer are also referred to as carrier block layers below. The material for a photoelectric conversion element of the present invention can be used in addition to the carrier block layer, but it is preferably used as an organic thin film layer of the carrier block layer. The carrier block layer may be composed of only the compound represented by the above formula (1), but may contain a known block material or the like in addition to the compound represented by the above formula (1).

In the electrode film used for the photoelectric conversion element of the present invention, when the photoelectric conversion layer included in the photoelectric conversion unit described later has a hole transporting property, or when the organic thin film layer other than the photoelectric conversion layer has a hole transporting property, holes When it is a transport layer, it plays a role of extracting holes from the photoelectric conversion layer and other organic thin film layers and collecting them, and when the photoelectric conversion layer included in the photoelectric conversion unit has electron transportability. Further, when the organic thin film layer is an electron transporting layer having electron transporting property, it plays a role of extracting electrons from the photoelectric conversion layer and other organic thin film layers and discharging them. Therefore, the material that can be used as the electrode film is not particularly limited as long as it has a certain degree of conductivity, but the adhesion to the adjacent photoelectric conversion layer and other organic thin film layers, electron affinity, ionization potential, stability, etc. It is preferable to select in consideration of. Materials that can be used as the electrode film include conductive metal oxides such as tin oxide (NESA), indium oxide, indium tin oxide (ITO) and indium zinc oxide (IZO); gold, silver, platinum, chromium and aluminum. , Metals such as iron, cobalt, nickel and tungsten; inorganic conductive substances such as copper iodide and copper sulfide; conductive polymers such as polythiophene, polypyrrole and polyaniline; carbon and the like. If necessary, a plurality of these materials may be mixed and used, or a plurality of these materials may be laminated in two or more layers. The conductivity of the material used for the electrode film is not particularly limited as long as it does not interfere with the light reception of the photoelectric conversion element more than necessary, but it is preferably as high as possible from the viewpoint of the signal strength of the photoelectric conversion element and the power consumption. For example, an ITO film having a conductivity of 300 Ω / □ or less functions sufficiently as an electrode film, but a commercially available substrate having an ITO film having a conductivity of several Ω / □ is also available. Therefore, it is desirable to use a substrate having such high conductivity. The thickness of the ITO film (electrode film) can be arbitrarily selected in consideration of conductivity, but is usually about 5 to 500 nm, preferably about 10 to 300 nm. Examples of the method for forming a film such as ITO include a conventionally known vapor deposition method, electron beam method, sputtering method, chemical reaction method, coating method and the like. The ITO film provided on the substrate may be subjected to UV-ozone treatment, plasma treatment, or the like, if necessary.

As the material of the transparent electrode film used for at least one of the electrode films on the side where light is incident, ITO, IZO, SnO ₂ , ATO (antimony-doped tin oxide), ZnO, AZO (Al-doped zinc oxide) , GZO (gallium-doped zinc oxide), TiO ₂ and FTO (fluorinated tin oxide) and the like. The transmittance of light incident through the transparent electrode film at the absorption peak wavelength of the photoelectric conversion layer is preferably 60% or more, more preferably 80% or more, and particularly preferably 95% or more. ..

Further, when a plurality of photoelectric conversion layers having different wavelengths to be detected are laminated, the electrode film used between the photoelectric conversion layers (this is an electrode film other than the pair of electrode films described above) is the respective photoelectric conversion. It is necessary to transmit light having a wavelength other than the light detected by the layer, and it is preferable to use a material that transmits 90% or more of the incident light, and a material that transmits 95% or more of the light is used for the electrode film. Is more preferable.

The electrode film is preferably plasma-free. By producing these electrode films in a plasma-free manner, the influence of plasma on the substrate on which the electrode film is provided can be reduced, and the photoelectric conversion characteristics of the photoelectric conversion element can be improved. Here, plasma-free means that plasma is not generated at the time of film formation of the electrode film, or the distance from the plasma generation source to the substrate is 2 cm or more, preferably 10 cm or more, more preferably 20 cm or more, so that the substrate is formed. It means a state in which the plasma that reaches is reduced.

Examples of devices that do not generate plasma during film formation of the electrode film include an electron beam vapor deposition device (EB vapor deposition device) and a pulse laser vapor deposition device. The method of forming a transparent electrode film using an EB vapor deposition apparatus is referred to as an EB vapor deposition method, and the method of forming a transparent electrode film using a pulse laser vapor deposition apparatus is referred to as a pulse laser vapor deposition method.

Examples of the apparatus capable of realizing a state in which the plasma at the time of film formation can be reduced include a counter-target type sputtering apparatus and an arc plasma vapor deposition apparatus.

When the transparent conductive film is used as an electrode film (for example, the first conductive film), a DC short circuit or an increase in leakage current may occur. One of the reasons for this is that fine cracks generated in the photoelectric conversion layer are covered with a dense film such as TCO (Transient Conductive Oxide), and the conduction between the film and the electrode film on the opposite side of the transparent conductive film is increased. it is conceivable that. Therefore, when a material having a relatively poor film quality such as Al is used for the electrode, the leakage current is unlikely to increase. By controlling the film thickness of the electrode film according to the film thickness (crack depth) of the photoelectric conversion layer, an increase in leakage current can be suppressed.

Usually, when the conductive film is made thinner than a predetermined value, a rapid increase in resistance value occurs. The sheet resistance of the conductive film in the photoelectric conversion element for an optical sensor of the present embodiment is usually 100 to 10,000 Ω / □, and the degree of freedom in film thickness is large. Further, the thinner the transparent conductive film, the smaller the amount of light absorbed, and generally the higher the light transmittance. When the light transmittance is high, the amount of light absorbed by the photoelectric conversion layer is increased and the photoelectric conversion ability is improved, which is very preferable.

The photoelectric conversion unit included in the photoelectric conversion element of the present invention includes a photoelectric conversion layer, a carrier block layer, and other organic thin film layers. An organic semiconductor film is generally used for the photoelectric conversion layer constituting the photoelectric conversion unit, but the organic semiconductor film may be one layer or a plurality of layers, and in the case of one layer, a P-type organic semiconductor film, An N-type organic semiconductor film or a mixed film thereof (bulk heterostructure) is used. On the other hand, in the case of a plurality of layers, there are about 2 to 10 layers, which is a structure in which any one of a P-type organic semiconductor film, an N-type organic semiconductor film, or a mixed film (bulk heterostructure) thereof is laminated, and the layers are layers. A buffer layer may be inserted in.

The organic semiconductor film of the photoelectric conversion layer has a triarylamine compound, a benzidine compound, a pyrazoline compound, a styrylamine compound, a hydrazone compound, a triphenylmethane compound, a carbazole compound, a polysilane compound, a thiophene compound, and a phthalocyanine, depending on the wavelength band to be absorbed. Compounds, naphthalocyanine compounds, cyanine compounds, merocyanine compounds, oxonor compounds, polyamine compounds, indol compounds, pyrrole compounds, pyrazole compounds, polyarylene compounds, carbazole derivatives, naphthalene derivatives, anthracene derivatives, chrysene derivatives, phenanthrene derivatives, pentacene derivatives, phenyl Butadiene derivatives, styryl derivatives, quinoline derivatives, tetracene derivatives, pyrene derivatives, perylene derivatives, fluorantene derivatives, quinacridone derivatives, coumarin derivatives, porphyrin derivatives, borondipyrromethene derivatives, fullerene derivatives and metal complexes (Ir complex, Pt complex, Eu complex, etc.) ) And the like can be used, but when the material for the photoelectric conversion element of the present invention is used as the carrier block layer, it is preferable to use the phthalocyanine compound for the photoelectric conversion layer.

The electron transport layer of the present invention plays a role of transporting electrons generated in the photoelectric conversion layer to the electrode film and a role of blocking holes from moving from the electrode film of the electron transport destination to the photoelectric conversion layer. The hole transport layer plays a role of transporting generated holes from the photoelectric conversion layer to the electrode film and a role of blocking the movement of electrons from the electrode film of the hole transport destination to the photoelectric conversion layer. The electron block layer plays a role of hindering the movement of electrons from the electrode film to the photoelectric conversion layer, preventing recombination in the photoelectric conversion layer, and reducing dark current. The hole block layer has a function of hindering the movement of holes from the electrode film to the photoelectric conversion layer, preventing recombination in the photoelectric conversion layer, and reducing dark current.
The hole block layer is formed by forming a film of hole blocking substances alone or by mixing two or more kinds, or by laminating two or more kinds. The hole-blocking substance is not limited as long as it is a compound capable of preventing holes from flowing out from the electrode to the outside of the device. Examples of the compound that can be used for the hole block layer include, in addition to the compound represented by the above formula (1), a phenanthroline derivative such as vasophenantroline and vasocuproin, a silol derivative, a quinolinol derivative metal complex, and an oxazole derivative. Examples thereof include oxazole derivatives and quinoline derivatives, and one or more of these can be used.

Although FIG. 1 shows a typical element structure of the photoelectric conversion element of the present invention, the present invention is not limited to this structure. In the example of the embodiment of FIG. 1, 1 is an insulating part, 2 is one electrode film (upper electrode film), 3 is an electron block layer, 4 is a photoelectric conversion layer, 5 is a hole block layer, and 6 is the other electrode film. (Lower electrode film), 7 represents an insulating base material or another photoelectric conversion element, respectively. Although the transistor for reading is not shown in the figure, it suffices if it is connected to the electrode film of 2 or 6, and if the photoelectric conversion layer 4 is transparent, the side opposite to the side on which the light is incident is opposite. It may be formed on the outside of the electrode film of. Light is incident on the photoelectric conversion element from either the upper part or the lower part unless the components other than the photoelectric conversion layer 4 extremely prevent the light of the main absorption wavelength of the photoelectric conversion layer from being incident. It may be.

[Organic EL element]
Next, an organic electroluminescence device (organic EL device), which is an aspect of a light emitting device using an organic thin film containing the material for a photoelectric conversion device of the present invention, will be described.
Organic EL devices have attracted attention because they can be used for applications such as self-luminous large-area color display and lighting, and many developments have been made. The structure has a structure in which two layers of a light emitting layer and a charge transport layer are provided between a counter electrode composed of a cathode and an anode; an electron transport layer, a light emitting layer and a hole transport layer laminated between the counter electrodes. Those having a structure having three layers; those having three or more layers; and the like are known, and those having a single light emitting layer and the like are also known.

FIG. 2 shows a typical element structure of an organic electroluminescence device which is one aspect of the organic electronic device of the present invention, but the present invention is not limited to this structure. In the example of the embodiment of FIG. 2, 1 represents a substrate, 2 represents an anode, 3 represents a hole injection layer, 4 represents a hole transport layer, 5 represents a light emitting layer, 6 represents an electron transport layer, and 7 represents a cathode.

Here, the hole transport layer has a function of injecting holes from the anode, transporting holes to the light emitting layer, facilitating the injection of holes into the light emitting layer, and a function of blocking electrons. Further, the electron transport layer has a function of injecting electrons from the cathode and transporting the electrons to the light emitting layer to facilitate the injection of electrons into the light emitting layer and a function of blocking holes. Further, in the light emitting layer, excitons are generated by recombination of the injected electrons and holes, and the energy radiated in the process of radiation deactivation of the excitons is detected as light emission.

The anode that can be used in an organic EL device is an electrode having a function of injecting holes into a hole injection layer, a hole transport layer, and a light emitting layer. Generally, metal oxides, metals, alloys, conductive materials, etc. with a work function of 4.5 eV or more are suitable. The material suitable for the anode of the organic EL element is not particularly limited, but for example, conductive metal oxides such as tin oxide (NESA), indium oxide, indium tin oxide (ITO) and indium zinc oxide (IZO), and gold. , Metals such as silver, platinum, chromium, aluminum, iron, cobalt, nickel and tungsten, inorganic conductive substances such as copper iodide and copper sulfide, conductive polymers such as polythiophene, polypyrrole and polyaniline, and carbon. Among these, it is preferable to use ITO or NESA.

The anode may use a plurality of materials if necessary, or may be composed of two or more layers made of different materials. The resistance of the anode is not limited as long as it can supply a sufficient current for light emission of the element, but it is preferably low resistance from the viewpoint of the power consumption of the element. For example, an ITO substrate having a sheet resistance value of 300 Ω / □ or less functions as an element electrode, but since it is possible to supply a substrate of about several Ω / □, it is desirable to use a low resistance product. The thickness of ITO can be arbitrarily selected according to the resistance value, but is usually used in the range of 5 to 500 nm, preferably 10 to 300 nm. Examples of the film forming method such as ITO include a vapor deposition method, an electron beam method, a sputtering method, a chemical reaction method, and a coating method.

A cathode that can be used in an organic EL device is an electrode having a function of injecting electrons into an electron injection layer, an electron transport layer, and a light emitting layer. Generally, metals and alloys with a small work function (approximately 4 eV or less) are suitable. Specific examples thereof include platinum, gold, silver, copper, iron, tin, zinc, aluminum, indium, chromium, lithium, sodium, potassium, calcium and magnesium, and the electron injection efficiency is improved to improve the element characteristics. Lithium, sodium, potassium, calcium or magnesium are preferred for this purpose. As the alloy, an alloy with a metal such as aluminum or silver containing a metal having a low work function, or an electrode having a structure in which these are laminated can be used. Inorganic salts such as lithium fluoride can also be used for the electrodes of the laminated structure. Further, when the light emission is taken out not to the anode side but to the cathode side, the cathode may be a transparent electrode capable of forming a film at a low temperature. Examples of the cathode film forming method include a vapor deposition method, an electron beam method, a sputtering method, a chemical reaction method, and a coating method, but the method is not particularly limited. The resistance of the cathode is not limited as long as it can supply a sufficient current for light emission of the element, but it is preferably low resistance from the viewpoint of power consumption of the element, and is preferably several hundred to several Ω / □. The film thickness of the cathode is usually in the range of 5 to 500 nm, preferably 10 to 300 nm.

The cathode is protected by oxides and nitrides such as titanium oxide, silicon nitride, silicon oxide, silicon nitride and germanium oxide, or mixtures thereof, polyvinyl alcohol, vinyl chloride, hydrocarbon-based polymers and fluorine-based polymers. It can be sealed with a dehydrating agent such as barium oxide, phosphorus pentoxide and calcium oxide.

Further, in order to extract light emission, it is generally preferable to fabricate an electrode on a substrate having sufficient transparency in the light emission wavelength region of the device. Examples of the transparent substrate include a glass substrate and a polymer substrate. Soda lime glass, non-alkali glass, quartz, etc. are used for the glass substrate. The thickness of the glass substrate may be sufficient to maintain the mechanical and thermal strength, and is preferably 0.5 mm or more. The material of the glass is preferably less elution ions from the glass, and examples thereof include non-alkali glass, but commercially available soda lime glass having a barrier coat such as SiO ₂ can also be used. Examples of the substrate made of a polymer other than glass include polycarbonate, polypropylene, polyether sulfone, polyethylene terephthalate, and an acrylic substrate.

The organic thin film of the organic EL element is formed of one layer or a plurality of layers between the electrodes of the anode and the cathode. By incorporating the compound represented by the above formula (1) into the organic thin film, an element that emits light by electric energy can be obtained.

The "layer" formed by the organic thin film is a hole transport layer, an electron transport layer, a hole transport light emitting layer, an electron transport light emitting layer, a hole block layer, an electron block layer, a hole injection layer, and an electron injection. It means a layer, a light emitting layer, or a single layer having the functions of these layers as shown in the following configuration example 9). The structure of the layer forming the organic thin film in the present invention may be any of the configurations listed in the following configuration examples 1) to 9).

Configuration example 1) Hole transport layer / electron transport light emitting layer.
2) Hole transport layer / light emitting layer / electron transport layer.
3) Hole transporting light emitting layer / electron transporting layer.
4) Hole transport layer / light emitting layer / hole block layer.
5) Hole transport layer / light emitting layer / hole block layer / electron transport layer.
6) Hole transporting light emitting layer / hole blocking layer / electron transporting layer.
7) In each of the combinations 1) to 6) above, a hole injection layer is further added before the hole transport layer or the hole transport light emitting layer.
8) In each of the combinations of 1) to 3) and 5) to 7), an electron injection layer is further added before the electron transport layer or the electron transport light emitting layer.
9) A configuration in which the materials used in the combinations 1) to 8) are mixed, and only one layer containing the mixed materials is provided.
Note that 9) may be provided with a single layer made of a material generally referred to as a bipolar light-emitting material; or a layer containing the light-emitting material and a hole-transporting material or an electron-transporting material. Generally, by forming a multilayer structure, electric charges, that is, holes and / or electrons can be efficiently transported, and these electric charges can be recombined. Further, by suppressing charge quenching and the like, it is possible to prevent a decrease in the stability of the device and improve the luminous efficiency.

The hole injection layer and the hole transport layer are formed by using the hole transport material alone or by laminating a mixture of two or more kinds of the materials. Examples of the hole transport material include N, N'-diphenyl-N, N'-di (3-methylphenyl) -4,4 "-diphenyl-1,1'-diamine, N, N'-dinaphthyl-N. , N'-diphenyl-4,4'-diphenyl-1,1'-diamine and other triphenylamines; bis (N-allylcarbazole) or bis (N-alkylcarbazole); pyrazoline derivatives, stilben compounds, Heterocyclic compounds typified by hydrazone compounds, triazole derivatives, oxadiazole derivatives and porphyrin derivatives; in polymer systems, polycarbonates and styrene derivatives having the above-mentioned monomers in the side chains, polyvinylcarbazoles, polysilanes and the like can be preferably used. It is not particularly limited as long as it is a substance capable of forming an organic thin film necessary for manufacturing an element, injecting holes from an electrode, and further transporting holes. As the hole injection layer provided between the hole transport layer and the anode for improving the hole injection property, a phthalocyanine derivative, m-MTDATA (4,4', 4''-tris [phenyl (m-tolyl)) ) Amino] Triphenylamine) and other starburst amines, and in the case of high molecular weight, polythiophene such as PEDOT (poly (3,4-ethylenedioxythiophene)), polyvinylcarbazole derivatives and the like.

The electron transport layer is formed by forming an electron transport material alone or by forming a mixture of two or more kinds of the materials. The electron transport material plays a role of transporting electrons from the negative electrode between the electrodes to which an electric field is applied, and is preferably one having high electron injection efficiency and efficiently transporting the injected electrons. For that purpose, the electron transport material is required to have a large electron affinity, a high electron mobility, excellent stability, and less likely to generate trap impurities during production and use. Kinolinol derivative metal complexes typified by tris (8-quinolinolato) aluminum complexes, tropolone metal complexes, perylene derivatives, perinone derivatives, naphthalimide derivatives, naphthalic acid derivatives, oxazole derivatives, oxaziazoles are examples of substances that satisfy these conditions. Derivatives, thiazole derivatives, thiazazole derivatives, triazole derivatives, bisstyryl derivatives, pyrazine derivatives, phenanthroline derivatives, benzoxazole derivatives, quinoxalin derivatives and the like can be mentioned, but are not particularly limited. These electron transporting materials may be used alone, but different electron transporting materials may be laminated or mixed and used. Examples of the electron injection layer provided between the electron transport layer and the cathode for improving the electron injection property include metals such as cesium, lithium and strontium, lithium fluoride and the like.

The hole blocking layer is formed by laminating or mixing a hole blocking substance alone or two or more kinds of substances. As the hole blocking substance, phenanthroline derivatives such as vasophenanthroline and vasocuproin, silol derivatives, quinolinol derivative metal complexes, oxadiazole derivatives, oxazole derivatives and the like are preferable. The hole-blocking substance is not particularly limited as long as it is a compound capable of preventing holes from flowing out from the cathode side to the outside of the device and reducing the luminous efficiency.

The light emitting layer means an organic thin film that emits light, and can be said to be, for example, a hole transport layer, an electron transport layer, or a bipolar transport layer having strong light emission. The light emitting layer may be formed of a light emitting material (host material, dopant material, etc.), which may be a mixture of the host material and the dopant material, or the host material alone. The host material and the dopant material may be one kind or a combination of a plurality of materials.

The dopant material may be included in the entire host material, partially, or in any part. The dopant material may be laminated, dispersed or either. Materials used for the light emitting layer include carbazole derivatives, anthracene derivatives, naphthalene derivatives, phenanthrene derivatives, phenylbutadiene derivatives, styryl derivatives, pyrene derivatives, perylene derivatives, quinoline derivatives, tetracene derivatives, perylene derivatives, quinacridone derivatives, and coumarin derivatives. Examples thereof include porphyrin derivatives and phosphorescent metal complexes (Ir complex, Pt complex, Eu complex, etc.).

The methods for forming an organic thin film of an organic EL element are generally resistance heating vapor deposition which is a vacuum process, electron beam deposition, sputtering, molecular lamination method, casting which is a solution process, spin coating, dip coating, blade coating, and wire bar. Coating methods such as coating and spray coating, printing methods such as inkjet printing, screen printing, offset printing, letterpress printing, soft lithography methods such as microcontact printing, and methods that combine multiple of these methods are adopted. Can be done. The thickness of each layer is not limited because it depends on the resistance value and charge mobility of each substance, but is selected from 0.5 to 5,000 nm. It is preferably 1 to 1,000 nm, more preferably 5 to 500 nm.

Among the organic thin films constituting the organic EL element, one layer or a plurality of organic thin films such as a light emitting layer, a hole transport layer, and an electron transport layer existing between the electrodes of the anode and the cathode are represented by the above formula (1). By containing the compound to be used, an element that emits light efficiently even with low electric energy can be obtained.

The compound represented by the above formula (1) can be suitably used as a hole block layer, a light emitting layer, and an electron transport layer, but is preferably used as a hole block layer. For example, it can be used in combination with the above-mentioned electron transport material, hole transport material, light emitting material, or the like, or can be mixed and used.

When the compound represented by the above formula (1) is used as a host material in combination with a dopant material, specific examples of the dopant material include a perylene derivative such as bis (diisopropylphenyl) perylenetetracarboxylic acid imide, a perinone derivative, and 4-. (Dicyanomethylene) -2-methyl-6- (p-dimethylaminostyryl) -4H-pyran (DCM) and its analogs, metal phthalocyanine derivatives such as magnesium phthalocyanine and aluminum chlorophthalocyanine, rhodamine compounds, deazaflavin derivatives, coumarin derivatives , oxazine compounds, squarylium compounds, violanthrone compound, Nile red, 5- Shianopirometen -BF ₄ pyrromethene derivatives complexes, further acetylacetone and benzoyl acetone and phenanthroline or Eu complex having a ligand as a phosphorescent material, Ir complexes, Ru Porphyrins such as complexes, Pt complexes and Os complexes, orthometal metal complexes and the like can be used, but are not particularly limited thereto. Further, when two kinds of dopant materials are mixed, it is also possible to efficiently transfer the energy from the host dye by using an assist dopant such as rubrene to obtain light emission with improved color purity. In either case, in order to obtain high luminance characteristics, it is preferable to dope with a high fluorescence quantum yield.

Since the concentration quenching phenomenon occurs when the dopant material is used in excess, the amount used is usually 30% by mass or less, preferably 20% by mass or less, and more preferably 10% by mass or less with respect to the host material. Examples of the method of doping the host material with the dopant material in the light emitting layer include a co-evaporation method with the host material, but the dopant material may be mixed with the host material in advance and then vapor-deposited at the same time. It can also be sandwiched between host materials. In this case, two or more dopant layers may be laminated with the host material.

Each of these dopant layers can be formed independently, or they may be mixed and used. Further, the dopant material is polyvinyl chloride, polycarbonate, polystyrene, polystyrene sulfonic acid, poly (N-vinylcarbazole), poly (methyl) (meth) acrylate, polybutylmethacrylate, polyester, polysulfone, as a polymer binder. Solvent-soluble resins such as polyphenylene oxide, polybutadiene, hydrocarbon resin, ketone resin, phenoxy resin, polysulfone, polyamide, ethyl cellulose, vinyl acetate, ABS resin (acrylonitrile-butadiene-styrene copolymer resin), polyurethane resin, phenol resin, It can also be used by being dissolved or dispersed in a curable resin such as xylene resin, petroleum resin, urea resin, melamine resin, unsaturated polyester resin, alkyd resin, epoxy resin or silicone resin.

The organic EL element can be suitably used as a flat panel display. It can also be used as a flat backlight, and in this case, either one that emits colored light or one that emits white light can be used. The backlight is mainly used for the purpose of improving the visibility of a display device that does not emit light by itself, and is used for a liquid crystal display device, a clock, an audio device, an automobile panel, a display board, a sign, and the like. In particular, liquid crystal display devices, especially conventional backlights for personal computer applications, for which thinning has become an issue, have been difficult to thin because they are composed of fluorescent lamps and light guide plates, but the light emission of the present invention Since the backlight using the element is characterized by being thin and lightweight, the above problem is solved. Similarly, it can be usefully used for lighting.

By using the compound represented by the above formula (1) of the present invention, it is possible to obtain an organic EL display device having high luminous efficiency and long life. Further, by combining the thin film transistor elements, it is possible to supply an organic EL display device in which the on / off phenomenon of the applied voltage is electrically controlled with high accuracy at low cost.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. The microwave synthesis reaction in the examples was carried out using Initiator + (Biotage). The structures of the compounds described in the synthetic examples were determined by mass spectrometry spectrum (MS) and nuclear magnetic resonance spectrum (NMR), if necessary. The MS spectrum in the examples was measured by GCMS-QP2020 (Shimadzu Corporation), the ¹ H NMR spectrum was measured by ECS400 (JEOL), and the absorption spectrum was measured by an ultraviolet visible spectrophotometer UV-1700 (Shimadzu Corporation). The melting point is a value measured by an M-565 melting point measuring device (Buch).

Example 1 (Synthesis of compound represented by the following formula (E1))
(Step 1) Synthesis of Intermediate Compound Represented by the following Formula (M-3) A commercially available 2,3,6,7-naphthalenetetracarboxylic dianhydride represented by the following formula (1-1) is placed in a flask. Compound (690 mg, 2.50 mmol) and concentrated sulfuric acid (25 ml) were charged and stirred to dissolve. N-Bromosuccinimide (4.45 g, 25 mmol) was added thereto, and the mixture was reacted at room temperature for 72 hours. Methanol (30 ml) was added to the reaction solution, and then water (50 ml) was added. The resulting mixed solution was extracted with ethyl acetate and the aqueous layer was extracted twice more with ethyl acetate. The obtained organic layer was concentrated under reduced pressure to obtain a solid. Dichloromethane (10 ml) and water (5 ml) were added to the obtained solid, and the mixture was stirred and dissolved. Dimethyl sulfate (1.89 g, 15 mmol) and a 40% aqueous tetrabutylammonium hydroxide solution (9.73 g, 15 mmol) were added thereto, and the mixture was reacted at room temperature for 5 hours. The reaction solution was extracted 3 times with ethyl acetate, and the obtained organic layer was concentrated under reduced pressure to obtain a solid. The obtained solid was purified by silica gel column chromatography to obtain 700 mg (0.74 mmol, yield 30%) of an intermediate compound represented by the following formula (M-3).

The measurement results of the mass spectrometric spectrum and the NMR spectrum of the intermediate compound represented by the formula (M-3) were as follows.
EI-MS (m / z): 516 ([M] ⁺ , 50%), 518 ([M] ⁺ , 100%), 520 ([M] ⁺ , 50%)
^{1 1} H NMR (400 MHz, CDCl ₃ ): δ8.80 (s, 2H), 4.01 (s, 6H), 3.99 (s, 6H)

(Step 2) Synthesis of intermediate compound represented by the following formula (M-4) Intermediate compound (259 mg, 0.50 mmol) represented by the formula (M-3) synthesized in step 1 in a flask, 3 , 5-Bis (trifluoromethyl) phenylboronic acid (516 mg, 2.0 mmol), [1,1'-bis (diphenylphosphino) ferrocene] -dichloropalladium (II) dichloromethane adduct (7.32 mg, 0. 01 mmol), potassium phosphate (637 mg, 3.0 mmol), and a 9: 1 mixed solvent (5 ml) of degassed toluene and water were charged, and the reaction was carried out at 170 ° C. for 1 hour using a microwave device. Water (10 ml) was added to the obtained mixture, and extraction was performed 3 times with ethyl acetate (10 ml). The obtained organic layer was concentrated under reduced pressure to obtain a solid. The obtained solid was purified by silica gel column chromatography to obtain 349 mg (0.445 mmol, yield 89%) of the intermediate compound represented by the following formula (M-4).

The measurement results of the mass spectrometric spectrum and the NMR spectrum of the intermediate compound represented by the formula (M-4) were as follows.
EI-MS (m / z): 784 [M] ^{+
1 1} H NMR (400 MHz, CDCl ₃ ): δ8.08 (s, 2H), 7.90 (s, 2H), 7.87 (s, 4H), 3.89 (s, 6H), 3.58 (S, 6H)

(Step 3) Synthesis of compound represented by the following formula (E1) Intermediate compound (319 mg, 0.41 mmol) represented by the formula (M-4) synthesized in step 2 and acetic acid (5 ml) were placed in a flask. The preparation was stirred. Methanesulfonic acid (1 mL, 15.4 mmol) was added thereto, the temperature was raised to 130 ° C., and the reaction was carried out for 3 hours. Volatile components were distilled off from the reaction solution by concentration under reduced pressure, and the obtained residual solid was purified by a vacuum sublimation purification method to obtain 164 mg (0.238 mmol, yield 58%) of the compound represented by the formula (E1). Obtained as a colorless solid.

The measurement results of the mass spectrometric spectrum, NMR spectrum and melting point of the compound represented by the formula (E1) were as follows.
EI-MS (m / z): 692 [M] ^{+
1 1} H NMR (400 MHz, Acetone-d6): δ8.72 (s, 2H), 8.41 (s, 2H), 8.33 (s, 4H)
Melting point: 357-358 ° C

Example 2 (Synthesis of compound represented by the following formula (E2))
(Step 4) Synthesis of intermediate compound represented by the following formula (M-5) An intermediate compound represented by the formula (M-3) synthesized in step 1 of Example 1 (259 mg, 0. 50 mmol), 3,5-bis (trifluoromethyl) phenylboronic acid (516 mg, 2.0 mmol), [1,1'-bis (diphenylphosphino) ferrocene] -dichloropalladium (II) dichloromethane adduct (7. 32 mg, 0.01 mmol), potassium phosphate (637 mg, 3.0 mmol), and a 9: 1 mixed solvent (5 ml) of degassed toluene and water were charged, and the reaction was carried out at 170 ° C. for 1 hour using a microwave device. went. Water (10 ml) was added to the obtained mixture, and extraction was performed 3 times with ethyl acetate (10 ml). The obtained organic layer was concentrated under reduced pressure to obtain a solid. The obtained solid was purified by silica gel column chromatography to obtain 349 mg (0.445 mmol, yield 89%) of the intermediate compound represented by the following formula (M-5).

The measurement results of the mass spectrometric spectrum and the NMR spectrum of the intermediate compound represented by the formula (M-5) were as follows.
EI-MS (m / z): 784 [M] ^{+
1 1} H NMR (400 MHz, CDCl ₃ ): δ8.08 (s, 2H), 7.90 (s, 2H), 7.87 (s, 4H), 3.89 (s, 6H), 3.58 (S, 6H)

(Step 5) Synthesis of compound represented by the following formula (E2) An intermediate compound (319 mg, 0.41 mmol) represented by the formula (M-5) synthesized in step 4 and acetic acid (5 ml) were placed in a flask. The preparation was stirred. Methanesulfonic acid (1 mL, 15.4 mmol) was added thereto, the temperature was raised to 130 ° C., and the reaction was carried out for 3 hours. Volatile components were distilled off from the reaction solution by concentration under reduced pressure, and the obtained residual solid was purified by a vacuum sublimation purification method to obtain 164 mg (0.238 mmol, yield 58%) of the compound represented by the formula (E2). Obtained as a colorless solid.

The measurement results of the mass spectrometric spectrum, NMR spectrum and melting point of the compound represented by the formula (E2) were as follows.
EI-MS (m / z): 692 [M] ^{+
1 1} H NMR (400 MHz, Acetone-d6): δ8.72 (s, 2H), 8.41 (s, 2H), 8.33 (s, 4H)
Melting point: 357-358 ° C

In the following examples and comparative examples of the photoelectric conversion element, the photoelectric conversion element was manufactured by a vapor deposition machine, and the application of current and voltage was measured in the atmosphere. The produced photoelectric conversion element was installed in a closed bottle-type measurement chamber (manufactured by ALS Technology Co., Ltd.) in a glove box having a nitrogen atmosphere, and current and voltage were applied and measured. The current and voltage application measurements were performed using a semiconductor parameter analyzer 4200-SCS (Keithley Instruments). Irradiation of the incident light was performed using PVL-3300 (manufactured by Asahi Spectroscopy Co., Ltd.) at an irradiation light wavelength of 550 nm and an irradiation light half width of 20 nm. The light-dark ratio in the examples shows the current value when light irradiation is performed divided by the current value in a dark place.

Example 3 (Preparation of photoelectric conversion element and its evaluation)
A 100 nm vacuum film of tin phthalocyanine as a photoelectric conversion layer is formed on ITO transparent conductive glass (manufactured by Geomatec Co., Ltd., ITO film thickness of 150 nm), and a hole block layer is represented by the above formula (1-1). The compound was formed into a 50 nm film by resistance heating vacuum deposition. Finally, 100 nm vacuum film was formed on aluminum as an electrode on the hole block layer to produce the photoelectric conversion element of the present invention.
For the photoelectric conversion element obtained above, the brightness ratio was calculated from the measurement results of the current value in a dark place and the current value during light irradiation when a voltage of 3 V was applied using ITO and aluminum as electrodes, and the results are shown in the table. Shown in 1.

Example 4 (Preparation of photoelectric conversion element and evaluation thereof)
A photoelectric conversion element was produced according to Example 3 except that the compound represented by the formula (E1) obtained in Example 1 was used instead of the compound represented by the formula (1-1). The light-dark ratio was calculated from the measurement results of the current value in a dark place and the current value at the time of light irradiation when a voltage of 3 V was applied using ITO and aluminum as electrodes, and the results are shown in Table 1.

Example 5 (Preparation of photoelectric conversion element and evaluation thereof)
A photoelectric conversion element was produced according to Example 3 except that the compound represented by the formula (E2) obtained in Example 2 was used instead of the compound represented by the formula (1-1). The light-dark ratio was calculated from the measurement results of the current value in a dark place and the current value at the time of light irradiation when a voltage of 3 V was applied using ITO and aluminum as electrodes, and the results are shown in Table 1.

Comparative Example 1 (Preparation of photoelectric conversion element for comparison and its evaluation)
For comparison, according to Example 3, except that 1,4,5,8-naphthalene-tetracarboxylic dianhydride (NTCDA) was used instead of the compound represented by the formula (1-1). A photoelectric conversion element was manufactured, and the light-dark ratio was calculated. The results are shown in Table 1.

Comparative Example 2 (Preparation of photoelectric conversion element for comparison and its evaluation)
For comparison, according to Example 3, except that 3,4,9,10-perylene-tetracarboxylic dianhydride (PTCDA) was used instead of the compound represented by the formula (1-1). A photoelectric conversion element was manufactured, and the light-dark ratio was calculated. The results are shown in Table 1.

Comparative Example 3 (Preparation of photoelectric conversion element for comparison and its evaluation)
A photoelectric conversion element for comparison was produced according to Example 3 except that fullerene (C60) was used instead of the compound represented by the formula (1-1), and the light-dark ratio was calculated. The results are shown in Table 1.

From the results in Table 1, the photoelectric conversion element of the present invention using the compound represented by the formula (1-1) or the formulas (E1) and (E2) in the hole block layer uses a known compound in the hole block layer. Since it showed a higher light-dark ratio and a dark current value that was an order of magnitude lower than that of the photoelectric conversion element for comparison used in the above, it has excellent leak prevention properties (in the dark) and is organic photoelectric. It is clear that it is suitable as a hole blocking material for conversion elements.

Example 6 (Synthesis of compound represented by the following formula (E3))
(Step 6) Synthesis of intermediate compound represented by the following formula (M-6) Intermediate compound (259 mg, 0.50 mmol) represented by the formula (M-3) synthesized in step 1 in a flask, phenyl. Boronic acid (244 mg, 2.0 mmol), [1,1'-bis (diphenylphosphino) ferrocene] -dichloropalladium (II) dichloromethane adduct (12 mg, 0.015 mmol), potassium phosphate (637 mg, 3.0 mmol) ), And a 9: 1 mixed solvent (20 ml) of degassed toluene and water was charged, and the reaction was carried out at 170 ° C. for 1 hour using a microwave synthesizer. Water (10 ml) was added to the obtained mixture, the mixture was filtered, extracted three times with ethyl acetate (10 ml), and the organic layer was washed three times with saturated brine (10 ml). The obtained organic layer was dried over anhydrous magnesium sulfate and then concentrated under reduced pressure to obtain a solid. The obtained solid was purified by silica gel column chromatography to obtain 195 mg (0.380 mmol, yield 76%) of the intermediate compound represented by the following formula (M-6).

The measurement results of the mass spectrometric spectrum and the NMR spectrum of the intermediate compound represented by the formula (M-6) were as follows.
EI-MS (m / z): 512 [M] ^{+
1 1} H NMR (400 MHz, CDCl ₃ ): δ8.07 (s, 2H), 7.55-7.47 (m, 6H), 7.38 (m, 4H), 3.85 (s, 6H) , 3.52 (s, 6H)

(Step 7) Synthesis of compound represented by the following formula (E3) Intermediate compound (160 mg, 0.31 mmol) represented by the formula (M-6) synthesized in step 6 and acetic acid (1.5 ml) in a flask. ) Was charged and stirred. Methanesulfonic acid (0.5 ml, 7.7 mmol) was added thereto, the temperature was raised to 130 ° C., and the reaction was carried out for 10 hours. After distilling off the volatile components from the reaction solution by concentration under reduced pressure, the precipitated solid was filtered and washed with a small amount of acetic acid. The obtained solid was purified by a vacuum sublimation purification method to obtain 90.7 mg (0.216 mmol, yield 70%) of the compound represented by the formula (E3) as a pale yellow solid.

The measurement results of the mass spectrometric spectrum, NMR spectrum and melting point of the compound represented by the formula (E3) were as follows.
EI-MS (m / z): 420 [M] ^{+
1 1} H NMR (400 MHz, Acetone-d6): δ8.49 (s, 2H), 7.71-7.68 (m, 6H), 7.62 (m, 4H)
Melting point: 400 ° C or higher

Example 7 (Synthesis of compound represented by the following formula (E4))
(Step 8) Synthesis of compound represented by the following formula (E4) Intermediate compound (273.4 mg, 0.528 mmol) represented by (M-3) synthesized in step 1 and acetic acid (1. 5 ml) was charged and stirred. Methanesulfonic acid (0.5 ml, 7.7 mmol) was added thereto, the temperature was raised to 130 ° C., and the reaction was carried out for 15.5 hours. After distilling off the volatile components from the reaction solution by concentration under reduced pressure, the precipitated solid was filtered and washed with a small amount of acetic acid. The obtained solid was purified by a vacuum sublimation purification method to obtain 165 mg (0.387 mmol, yield 73%) of the compound represented by the formula (E4) as a yellow solid.

The measurement results of the mass spectrometric spectrum, NMR spectrum and melting point of the compound represented by the formula (E4) were as follows.
EI-MS (m / z): 424 [M] ⁺ , 55%, 426 [M] ⁺ , 100%, 428 [M] ⁺ , 51%
^{1 1} H NMR (400 MHz, acetone-d6): δ9.34 (s, 2H)
Melting point: 322-325 ° C

FIG. 4 shows the results of the light absorption spectrum when each compound of the formula (1-1), the formula (E1), the formula (E2), the formula (E3) and the formula (E4) is made into a thin film state. From the results of the light absorption spectrum, each compound of the formula (1-1), the formula (E1), the formula (E2), the formula (E3) and the formula (E4) is in the visible light region (400 to 800 nm) in the thin film state. It was found that it does not have a main absorption band. Therefore, by using these compounds in the block layer, it is possible to obtain a suitable block layer that does not interfere with the irradiation light from the outside to the photoelectric conversion layer.

By using the material for a photoelectric conversion element of the present invention containing a compound having a specific structure, the photoelectric conversion element is excellent in required characteristics such as hole or electron leakage prevention and transportability, heat resistance and visible light transparency. Can be provided.

(Fig. 1)
1 Insulation part 2 Upper electrode film 3 Electronic block layer 4 Photoelectric conversion layer 5 Hole block layer 6 Lower electrode film 7 Insulating base material or other photoelectric conversion element

(Fig. 2)
1 Substrate 2 Anode 3 Hole injection layer 4 Hole transport layer 5 Light emitting layer 6 Electron transport layer 7 Cathode

Claims (11)

The following formula (1)

(In the formula (1), R ^{1 to} R ⁴ independently represent a hydrogen atom, an aromatic group, a heterocyclic group, an aliphatic hydrocarbon group or a halogen atom. X represents an oxygen atom or a sulfur atom.) A material for a photoelectric conversion element containing a compound represented by. The material for a photoelectric conversion element according to claim 1, wherein X is an oxygen atom. R ¹ and R ² are hydrogen atoms, one of R ³ and R ⁴ is a hydrogen atom, an aromatic group, a heterocyclic group, an aliphatic hydrocarbon group or a halogen atom, and the other is an aromatic group or a heterocycle. The material for a photoelectric conversion element according to claim 1 or 2, which is a group, an aliphatic hydrocarbon group or a halogen atom. An organic thin film containing the material for a photoelectric conversion element according to any one of claims 1 to 3. A photoelectric conversion element containing the organic thin film according to claim 4. The photoelectric conversion element according to claim 5, wherein the organic thin film is a hole block layer. The photoelectric conversion element according to claim 5 or 6, which is a light emitting element. An image pickup device in which a plurality of photoelectric conversion elements according to any one of claims 5 to 7 are arranged in an array. An optical sensor including the photoelectric conversion element according to claim 5 or the image pickup element according to claim 8. The following formula (2)

(In formula (2), one of R ⁵ and R ⁶ represents a hydrogen atom, an aromatic group, a heterocyclic group, an aliphatic hydrocarbon group or a halogen atom, and the other represents an aromatic group, a heterocyclic group or an aliphatic group. A compound represented by a hydrocarbon group or a halogen atom. X represents an oxygen atom or a sulfur atom). The compound according to claim 10, wherein X is an oxygen atom.

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