JP2022002241A - Photoelectric conversion element and composition for forming photoelectric conversion layer - Google Patents

Abstract

To provide a photoelectric conversion element having excellent durability and a composition for forming a photoelectric conversion layer.SOLUTION: In a photoelectric conversion element having a photoelectric conversion layer between a pair of electrodes, the photoelectric conversion layer includes a surface treatment agent and semiconductor particles, and the surface treatment agent includes at least one partial structure selected from the group consisting of a diarylamine skeleton, a quinoline skeleton, and an indole skeleton, and at least one group selected from a carboxyl group and a sulfanyl group.SELECTED DRAWING: None

Description

The present invention relates to a photoelectric conversion element and a composition for forming a photoelectric conversion layer.

Photoelectric conversion elements that convert light energy into electrical energy are used in solar cells, photosensors, copiers, and the like. Of these, optical sensors that use near-infrared light as light energy are attracting attention for their use in night vision, ranging, security, semiconductor wafer inspection, and the like. Quantum dots are nano-sized semiconductor particles that show a broad absorption spectrum and can control the wavelength of the absorption edge by the size of the particle size. Therefore, they have been used as materials for photoelectric conversion in recent years such as photoelectric conversion elements and solar cells. Research is being conducted. In particular, a ligand coordinated to the surface of a quantum dot has been studied in order to improve the characteristics of the photoelectric conversion element.

For example, in Patent Document 1, by changing the ligand on the surface of the quantum dot surface made of PbSe from oleic acid to 1,3-benzenedithiol, the quantum dots are brought closer to each other and the electrical conductivity of the photoactive layer is increased. It has been reported.
Further, in Patent Document 2, by using a halide salt of benzenethiol, benzenedithiol, 3-mercaptopropionic acid, ethylenediamine, tetrabutylammonium, etc. as a ligand, the energy level of the quantum dots is controlled and the characteristics of the photoelectric conversion element are improved. It is disclosed to do.
In addition, Non-Patent Document 1 includes cinnamic acid, 4-cyanocinnamic acid, 4-trifluoromethyl cinnamic acid, 3,5-difluoro cinnamic acid, 2,6-difluoro cinnamic acid, 4-methoxy cinnamic acid, 4- It is disclosed that the use of dimethylaminocinnamic acid as a ligand controls the energy level of quantum dots and improves the characteristics of photoelectric conversion elements.

Special Table 2016-532301 Publication No. Special Table 2017-516320 Gazette

Daniel M. Kropa et al., "Tuning colloidal quantum dot band edge possession solution-phase surface chemistry modification" (NATURE COMMUNICATIONS | DOI: 10.1038 / DOI: 10.1038 / DOI: 10.1038 /

However, in the above technique, there is a problem that the device performance created by using the quantum dots is not stable over time and the durability is inferior. Therefore, an object to be solved by the present invention is to provide a photoelectric conversion element having excellent durability and a composition for forming a photoelectric conversion layer.

The present inventors have reached the present invention as a result of repeated diligent studies to solve the above problems.
That is, the present invention is a photoelectric conversion element having a photoelectric conversion layer between a pair of electrodes, wherein the photoelectric conversion layer contains a surface treatment agent and semiconductor particles, and the surface treatment agent is a diallylamine. The present invention relates to a photoelectric conversion element having at least one partial structure selected from the group consisting of a skeleton, a quinoline skeleton and an indole skeleton, and at least one group selected from the group consisting of a carboxyl group and a sulfanyl group.

The present invention also relates to the photoelectric conversion element in which the surface treatment agent has a structure represented by the following general formula (1), general formula (2) or general formula (3).
General formula (1)

[In the general formula (1), X ¹ is a hydrogen atom, an alkyl group which may have a substituent, an aryl group which may have a substituent, or an acyl group which may have a substituent. , R ^{1 to} R ⁸ are independently hydrogen atom, an alkyl group which may have a substituent, an aryl group which may have a substituent, an alkoxy group which may have a substituent, and a substituent. An aryloxy group which may have a group, an acyl group which may have a substituent, an amino group which may have a substituent, a (poly) organosiloxy group which may have a substituent, and a carboxyl group. Alternatively, it is a sulfanyl group, and ^{at least one of X 1} and R ^{1 to} R ⁸ is a carboxyl group, a sulfanyl group, a group having a carboxyl group, or a group having a sulfanyl group. ]

General formula (2)

[In the general formula (2), R ^{11 to} R ²⁵ each independently have a hydrogen atom, an alkyl group which may have a substituent, an aryl group which may have a substituent, and a substituent. May have an alkoxy group, an aryloxy group which may have a substituent, an acyl group which may have a substituent, a (poly) organosiloxy group which may have a substituent, a nitro group, and a substituent. It is an amino group, a carboxyl group or a sulfanyl group which may have ^{, and at least one of R 11 to} R ²⁵ is a carboxyl group, a sulfanyl group, a group having a carboxyl group or a group having a sulfanyl group. ]

General formula (3)

[In the general formula (3), X ² has a hydrogen atom, an alkyl group which may have a substituent, an aryl group which may have a substituent (excluding a phenyl group), or a substituent. R ^{26 to} R ³⁵ may independently have a hydrogen atom, an alkyl group which may have a substituent, an aryl group which may have a substituent, and a substituent. It has an alkoxy group which may have a substituent, an aryloxy group which may have a substituent, a (poly) organosiloxy group which may have a substituent, an amino group which may have a substituent, and a substituent. It is also a good acyl group, carboxyl group or sulfanyl group, and ^{at least one of X 2} and R ^{26 to} R ³⁵ is a carboxyl group, a sulfanyl group, a group having a carboxyl group or a group having a sulfanyl group. ]

The present invention also relates to the photoelectric conversion element according to claim 1 or 2, wherein the semiconductor particles can absorb electromagnetic waves having a wavelength of 700 to 2500 nm.

Further, the present invention relates to a semiconductor particle, PbS, relates the photoelectric conversion element comprising a PbSe and Ag ₂ one or more kinds of selected from the group Ru consisting S.

Further, the present invention is a surface treatment agent having at least one partial structure selected from the group consisting of a diarylamine skeleton, a quinoline skeleton and an indole skeleton, and at least one group selected from the group consisting of a carboxyl group and a sulfanyl group. The present invention relates to a composition for forming a photoelectric conversion layer containing and semiconductor particles.

According to the present invention, a photoelectric conversion element having excellent durability can be obtained.

Hereinafter, embodiments of the present invention will be described.
<photoelectric conversion layer>
The photoelectric conversion layer contributes to charge separation and has a function of transporting electrons and holes generated by absorption of electromagnetic waves (mainly light) toward electrodes in opposite directions, respectively. The photoelectric conversion layer used in the present invention has a function of transporting electrons and holes. The conversion layer is a surface treatment agent and semiconductor particles having at least one partial structure selected from the group consisting of a diarylamine skeleton, a quinoline skeleton and an indole skeleton, and at least one group selected from the group consisting of a carboxyl group and a sulfanyl group. And includes.

<Semiconductor particles>
The photoelectric conversion layer contains semiconductor particles. As used herein, the semiconductor particles refer to particles made of semiconductors having an average particle size of 0.5 nm to 100 nm. From the viewpoint of improving stability and photoelectric conversion efficiency, the average particle size of the semiconductor particles is preferably 1 nm or more, more preferably 1.5 nm or more, still more preferably 2 nm or more, and improve film forming property and photoelectric conversion efficiency. From the viewpoint of allowing the particles to grow, it is preferably 20 nm or less, more preferably 10 nm or less. The particle size of the semiconductor particles in the present specification is a numerical value measured by observation with a transmission electron microscope. The semiconductor particles preferably contain compound semiconductors. The compound semiconductor consists of a group consisting of Group 1 elements, Group 2 elements, Group 10 elements, Group 11 elements, Group 12 elements, Group 13 elements, Group 14 elements, Group 15 elements, Group 16 elements and Group 17 elements. It is preferably a semiconductor composed of a compound containing at least two selected elements. It is preferable that the semiconductor particles can absorb electromagnetic waves having a wavelength of 700 to 2500 nm. An electromagnetic wave having a wavelength of 700 to 2500 nm is generally called near-infrared light (also referred to as near-infrared light), and in order for a semiconductor particle to absorb an electromagnetic wave having a wavelength of 700 to 2500 nm, the semiconductor particle has an electromagnetic wave having a wavelength of 700 to 2500 nm. It preferably contains a compound semiconductor that can be absorbed. Examples of the compound semiconductor capable of absorbing electromagnetic waves having a wavelength of 700 to 2500 nm include compound semiconductors having a perovskite crystal structure and metal chalcogenides (for example, oxides, sulfides, selenes, and tellurides). Specific examples of the compound semiconductor having a perovskite crystal structure include CH ₃ NH ₃ PbF ₃ , CH ₃ NH ₃ PbCl ₃ , CH ₃ NH ₃ PbBr ₃ , CH ₃ NH ₃ PbI ₃ , CsPbF ₃ , CsPbCl ₃ , and CsPbBr. ₃ , CsPbI ₃ , RbPbF ₃ , RbPbCl ₃ , RbPbBr ₃ , RbPbI ₃ , KPbF ₃ , KPbCl ₃ , KPbBr ₃ , KPbI _{3 and the} like. Specific examples of the metal chalcogenide include PbS, PbSe, PbTe, CdS, CdSe, CdTe, Sb ₂ S ₃ , Bi ₂ S ₃ , Ag ₂ S, Ag ₂ Se, Ag ₂ Te, Au ₂ S, and so on. Au ₂ Se, Au ₂ Te, Cu ₂ S, Cu ₂ Se, Cu ₂ Te, Fe ₂ S, Fe ₂ Se, Fe ₂ Te, In ₂ S 3, SnS, SnSe, SnTe, CuInS ₂ , CuInSe ₂ , CuInTe ₂ , EuS, EuSe, EuTe and the like. Among these, PbS, PbSe, Ag ₂ S is preferred.

<Surface treatment agent>
The surface treatment agent in the present invention has at least one partial structure selected from the group consisting of a diarylamine skeleton, a quinoline skeleton and an indole skeleton, and at least one group selected from the group consisting of a carboxyl group and a sulfanyl group. Here, the carboxyl group and the sulfanil group act as adsorption sites for the surface of the semiconductor particles. The surface treatment agent may be used alone or in combination of two or more. The diarylamine skeleton further includes a triarylamine skeleton having an aryl group on an amine nitrogen atom and a carbazole skeleton in which aryl groups are bonded to each other to form a ring.

The surface treatment agent preferably has a diarylamine skeleton because of the durability of the photoelectric conversion element over time. More preferably, it is a surface treatment agent having a structure represented by the general formula (1), the general formula (2) or the general formula (3). It is presumed that this is excellent in the shielding effect against oxygen and water that deteriorate the semiconductor particles.

Hereinafter, the substituents in the above general formulas (1) to (3) will be described.
The alkyl group is a linear or branched alkyl group, and the molecular weight of the treatment agent is preferably small and the number of carbon atoms of the alkyl group is 1 from the viewpoint that the content of semiconductor fine particles in the composition can be increased. It is preferably ~ 30. Examples of the alkyl group include a linear alkyl group such as a methyl group, an ethyl group, a hexyl group, a dodecyl group and an eicosyl group; and a branched alkyl group such as a 2-ethylhexyl group.

The aryl group is a residue obtained by formally removing one hydrogen atom from the aromatic hydrocarbon ring, and more preferably, the residue obtained by formally removing one hydrogen atom from the aromatic hydrocarbon ring having 6 to 30 carbon atoms. It is the basis. Examples of the aromatic hydrocarbon ring include a benzene ring, a naphthalene ring, a pyrene ring, a biphenyl group, and a terphenyl group.

The alkoxy group is a group in which an alkyl group is bonded on an oxygen atom, and the alkyl group has the same meaning as the above-mentioned alkyl group. In order to increase the content of the semiconductor particles in the composition, the molecular weight of the surface treatment agent is preferably small, and the number of carbon atoms of the alkyl group is preferably 1 to 6.

The aryloxy group is a group in which an aryl group is bonded on an oxygen atom, and the aryl group is synonymous with the above-mentioned aryl group. In order to increase the content of the semiconductor particles in the composition, the molecular weight of the surface treatment agent is preferably small, and the number of aryl groups is preferably 1 to 2.

The acyl group is a group to which an alkyl group or an aryl group is bonded via a carbonyl group, and the alkyl group and the aryl group are synonymous with the above-mentioned alkyl group and aryl group. In order to increase the content of the semiconductor particles in the composition, the molecular weight of the surface treatment agent is preferably small, and in the case of an alkyl group, the number of carbon atoms is preferably 1 to 6. Further, in the case of an aryl group, the number of aryl groups is preferably 1 to 2.

Examples of the amino group which may have a substituent include an amino group and a substituted amino group. Examples of the substituent of the substituted amino group include an alkyl group, an aryl group or an acyl group. The alkyl group, aryl group and acyl group are synonymous with the alkyl group, aryl group or acyl group. In order to increase the content of the semiconductor particles in the composition, the molecular weight of the surface treatment agent is preferably small, and the alkyl group and the alkyl group constituting the acyl group preferably have 1 to 4 carbon atoms. Further, the aryl group and the aryl group constituting the acyl group preferably have 1 to 2 aryl groups.

Further, the alkyl group, aryl group, alkoxy group, amino group, aryloxy group and acyl group in the general formulas (1) to (3) may have a substituent. Examples of the substituent which may be possessed include a halogeno group, a cyano group, a hydroxyl group, a nitro group, an alkoxy group, an alkyl group, an aralkyl group, an aryl group, an aryloxy group, a syroxy group, an alcoholoxy group and an alkoxycarbonyloxy. Group, aryloxyalconoyl group, amino group, anilino group, alconoylamino group, carbamoylamino group, aryloxycarbonylamino group, sulfamoylamino group, alkylsulfonylamino group, carbamoylarylamino group, sulfanyl group, alkylthio group , Arylthio group, alkylsulfinyl group, arylsulfinyl group, alkylsulfonyl group, arylsulfonyl group, imide group, phosphino group, phosphinyl group, phosphinyloxy group, phosphinylamino group, silyl group, group containing siloxane bond, Examples thereof include a carboxyl group and a sulfanyl group.
The substituent which may be possessed in the present invention includes the above-mentioned monovalent substituent and a divalent linking group such as an alkylene group, an arylene group, an ether group, an ester group, a sulfide group, a carbonyl group and an imino group. It may be a bonded monovalent group.

Examples of the group having a carboxyl group or a sulfanyl group include a monovalent group having a carboxyl group or a sulfanyl group as a substituent, such as an alkyl group, an alkylene group, an aryl group, an alkoxy group and an aryloxy group.

Examples of the alkyl group having a carboxyl group or the aryl group having a carboxyl group include a 2-carboxylethyl group, a 2,2-dicarboxyethyl group, a 2-carboxyethenyl group and a 2-cyano-2-carboxyethenyl group. Examples thereof include a group, a 2-trifluoromethyl-2-carboxyethenyl group, a 2-fluoro-2-carboxyethenyl group and the like.
It is preferable that the carboxyl group is directly bonded to the diarylamine skeleton, the quinoline skeleton and the indole skeleton, or the carboxyl group is bonded to the diarylamine skeleton, the quinoline skeleton and the indole skeleton at a position capable of coupling.

Examples of the alkyl group having a sulfanyl group, the aryl group having a sulfanyl group, or the acyl group having a sulfanyl group include [(3-sulfanylpropanoyl) oxy] ethyl group and [(2-sulfanylacetyl) oxy] ethyl group. , 4- (Sulfanylmethyl) phenyl group, [(3-sulfanylpropanol) oxy] propyl group, 3-sulfanyl [(3-sulfanylpropanoyl) oxy] ethyl group, {[(2-sulfanylethoxy) propanoyl] oxy } Ethyl group and the like can be mentioned. In order to increase the content of semiconductor particles in the composition, the molecular weight of the surface treatment agent is preferably small, and the molecular weight of the alkyl group having a sulfanyl group, the aryl group having a sulfanyl group, or the acyl group having a sulfanyl group is , 200 or less is preferable.

The surface treatment agent may be cis-type, trans-type, or a mixture of cis-type and trans-type isomers when cis-type and trans-type geometric isomers are present. good. The same applies to the thin-anti geometric isomerism.

<photoelectric conversion element>
The photoelectric conversion element of the present invention has the above-mentioned photoelectric conversion layer between a pair of electrodes. In the photoelectric conversion element of the present invention, a known configuration of a photoelectric conversion element can be applied. Further, the photoelectric conversion element of the present invention can be manufactured by a known method except for the photoelectric conversion layer.

Here, a photoelectric conversion element that can be produced by using the composition for forming a photoelectric conversion layer of the present invention will be described in detail. Generally, a photoelectric conversion element using semiconductor particles is composed of at least a pair of electrodes and a photoelectric conversion layer. For the purpose of improving the photoelectric conversion efficiency, various types of device structures have been proposed depending on the energy matching between the electrode and the semiconductor particles and the method for producing the photoelectric conversion layer composed of the semiconductor particles. For example, the photoelectric conversion layer forming composition of the present invention can be used to produce a photoelectric conversion element having the following known configurations.

1. 1. Schottky type photoelectric conversion element A photoelectric conversion element that obtains photovoltaic power by using a Schottky barrier formed at the interface between an electron-donating (p-type) or electron-accepting (n-type) semiconductor particle and an electrode. .. For example, when a p-type photoelectric conversion layer is used, a Schottky barrier is formed at the interface between the pair of electrodes and the electrode having the smaller internal work function, and charge separation occurs at the interface to perform photoelectric conversion. ..

2. 2. Bilayer heterojunction photoelectric conversion element Electron-donating (p-type) and electron-accepting (n-type) semiconductor particles and other semiconductor materials are individually formed between a pair of electrodes, and light charges are applied to the pn junction interface. It is a photoelectric conversion element that causes separation and obtains a photocurrent.

3. 3. Bulk heterojunction type photoelectric conversion element An organic semiconductor layer is formed by mixing electron-donating (p-type) and electron-accepting (n-type) semiconductor particles and other semiconductor materials at an arbitrary ratio between a pair of electrodes. At this time, the p-type and n-type materials may be uniformly dispersed or non-uniform. Since photocharge separation occurs at the interface formed by each p-type material and n-type material, it is possible to form a wider pn junction than the bilayer heterojunction type.

<Electrode>
It is preferable that at least one of the pair of electrodes constituting the photoelectric conversion element transmits light. Specific examples include conductive metal oxides such as tin oxide, zinc oxide, indium oxide, and indium tin oxide (ITO), or gold, silver, platinum, chromium, nickel, lithium, indium, aluminum, calcium, and magnesium. And the like, and examples thereof include a mixture or a laminate of these metals and a conductive metal oxide.

The electrode is generally flat, but may be corrugated, pyramidal, comb-shaped or the like in order to improve energy conversion efficiency. As a method for forming these electrodes, a general electrode forming method can be used, and a PVD method such as a vacuum vapor deposition method, a sputtering method, and an ion plating method, a CVD method, a chemical reaction method (sol-gel method, etc.), and casting can be used. Examples thereof include a method, a spray coating method, an inkjet method, and a spin coating method.
The photoelectric conversion element may include a layer other than the photoelectric conversion layer between the pair of electrodes, and has a hole injection layer, a hole transport layer, an electron transport layer, and / or an electron injection layer. May be good.

<Hole injection layer>
For the hole injection layer, a hole injection material that exhibits an excellent hole injection effect on the photoelectric conversion layer and can form a hole injection layer having excellent adhesion to the anode interface and thin film formation is used. .. Further, when such a material is laminated in multiple layers and a material having a high hole injection effect and a material having a high hole transport effect are laminated in multiple layers, the materials used for each are referred to as a hole injection material and a hole transport material. Sometimes. These hole injection materials and hole transport materials need to have a large hole mobility and a small ionization energy of usually 5.5 eV or less. For the hole injecting layer is preferably made of a material which can transport holes to the emitting layer at a lower electric field intensity, further hole mobility is, for example, 10 ⁴ to 1
0 at ⁶ V / cm electric field is applied, those that are least 10 ^-6 cm ² / V · sec is preferred. The hole injecting material and the hole transporting material are not particularly limited as long as they have the above-mentioned preferable properties, and are conventionally used as a hole charge transporting material in an optical transmission material or an organic EL element. Any known hole used for the hole injection layer can be selected and used.

Examples of such a hole injecting material and a hole transporting material include a triazole derivative (see US Pat. No. 3,112,197) and an oxadiazole derivative (see US Pat. No. 3,189,447). ), Imidazole derivative (see Japanese Patent Publication No. 37-1609, etc.), polyarylalkane derivative (US Pat. Nos. 3,615,402, 3,820,989, 3,542,544). No. 45-555, No. 51-10983, No. 51-93224, No. 55-17105, No. 56-4148, No. 55-108667, No. 55-15953A, 56-36656, etc.), Pyrazoline derivative and Pyrazolone derivative (US Pat. Nos. 3,180,729, 4,278,746, JP-A-55- No. 88064, No. 55-88065, No. 49-105537, No. 55-51086, No. 56-80051, No. 56-88141, No. 57-45545, No. 54-112637. No. 55-74546, etc.), phenylenediamine derivatives (US Pat. Nos. 3,615,404, Japanese Patent No. 51-10105, No. 46-3712, No. 47-25336). , JP-A-54-53435, JP-A-541-10536, JP-A-54-119925, etc.), arylamine derivatives (US Pat. Nos. 3,567,450, 3,180,703). No. 3, 240,597, No. 3,658,520, No. 4,232,103, No. 4,175,961, No. 4,175,961 4,012,376, Japanese Patent Publication No. 49-35702, Japanese Patent Application Laid-Open No. 59-27577, Japanese Patent Application Laid-Open No. 55-144250, Japanese Patent Application Laid-Open No. 56-119132, Japanese Patent Publication No. 56-22437, Western German Patent No. Disclosed in 1,110,518, etc.), amino-substituted calcon derivatives (see US Pat. No. 3,526,501, etc.), oxazole derivatives (see US Pat. No. 3,257,203, etc.) ), Styrylanthracene derivative (see JP-A-56-46234, etc.), fluorenone derivative (see JP-A-54-110837, etc.), Hydrazone derivative (US Pat. Kaisho 54-59143, Gaz. 55-520 See No. 63, No. 55-52064, No. 55-46760, No. 55-85495, No. 57-11350, No. 57-148949, No. 2-311591, etc.). Stilbene Derivatives (Japanese Patent Laid-Open No. 61-210363, No. 61-228451, No. 61-14642, No. 61-72255, No. 62-47646, No. 62-36674, No. 62. See -10652, 62-30255, 60-93455, 60-94462, 60-174749, 60-175052, etc.), stilbene derivatives (US Patent No. 4). , 950, 950), Polysilane-based (Japanese Patent Laid-Open No. 2-204996), Aniline-based copolymer (Japanese Patent Laid-Open No. 2-282263), Conductiveness disclosed in JP-A 1-211399. Examples thereof include polymer oligomers (particularly thiophene oligomers).

Further, as a hole injecting material and a hole transporting material, a porphyrin compound (Japanese Patent Laid-Open No. 63-2956965), an aromatic tertiary amine compound and a styrylamine compound (US Pat. No. 4,127,412). Japanese Patent Laid-Open Nos. 53-27033, 54-58445, 54-149634, 54-64299, 55-79450, 55-144250, 56-119132. , No. 61-295558, No. 61-98353, No. 63-295695, etc.) can also be used. For example, 4,4'-bis (N- (1-naphthyl) -N-phenylamino) biphenyl having two fused aromatic rings in the molecule described in US Pat. No. 5,061,569, etc. , 4,4', 4 "-tris (N- (3-methylphenyl) -N-phenyl" in which three triphenylamine units described in JP-A-4-308688 are linked in a starburst type. Amino) Triphenylamine and the like can be mentioned. Further, phthalocyanine derivatives such as copper phthalocyanine and hydrogen phthalocyanine can be mentioned as the hole injection material. Further, aromatic dimethylidene compounds, p-type Si, p-type SiC and the like can be mentioned. Inorganic compounds can also be used as hole injection materials and hole transport materials.

Further, materials that can be used for the hole injection layer include molybdenum oxide (MnO _x ), vanadium oxide (VO _x ), ruthenium oxide (RuO _x ), copper oxide (CuO _x ), tungsten oxide (WO _x ), and iridium oxide. Inorganic oxides such as (IrO _x ) and their dopes are also mentioned.

Specific examples of the aromatic tertiary amine compound include, for example, N, N'-diphenyl-N, N'-(3-methylphenyl) -1,1'-biphenyl-4,4'-diamine, N, N, N', N'-(4-methylphenyl) -1,1'-phenyl-4,4'-diamine, N, N, N', N'-(4-methylphenyl) -1,1'-Biphenyl-4,4'-diamine, N, N'-diphenyl-N, N'-dinaphthyl-1,1'-biphenyl-4,4'-diamine, N, N'-(methylphenyl) -N, N'-(4-n-butylphenyl) -phenanthrene-9,10-diamine, N, N-bis (4-di-4-tolylaminophenyl) -4-phenyl-cyclohexane, N, N'-bis ( 4'-diphenylamino-4-biphenylyl) -N, N'-diphenylbenzidine, N, N'-bis (4'-diphenylamino-4-phenyl) -N, N'-diphenylbenzidine, N, N'- Bis (4'-diphenylamino-4-phenyl) -N, N'-di (1-naphthyl) benzidine, N, N'-bis (4'-phenyl (1-naphthyl) amino-4-phenyl) -N , N'-diphenylbenzidine, N, N'-bis (4'-phenyl (1-naphthyl) amino-4-phenyl) -N, N'-di (1-naphthyl) benzidine and the like, which are positive. It can be used for both hole injection materials and hole transport materials.
Tables 1 and 2 show particularly preferable examples of the hole injection material.

In order to form the hole injection layer, the above-mentioned compound is thinned by a known method such as a vacuum deposition method, a spin coating method, a casting method, or a Langmuir-Brojet method (LB method). The film thickness of the hole injection layer is not particularly limited, but is usually 5 nm to 5 μm.

<Electron injection layer>
For the electron injection layer, an electron injection material that exhibits an excellent electron injection effect on the photoelectric conversion layer and can form an electron injection layer having excellent adhesion to the cathode interface and thin film forming property is used. Examples of such electron-injected materials include metal complex compounds, nitrogen-containing five-membered ring derivatives, fluorenone derivatives, anthraquinodimethane derivatives, diphenoquinone derivatives, thiopyrandioxide derivatives, perylenetetracarboxylic acid derivatives, fleolenilidenemethane. Examples thereof include derivatives, anthron derivatives, silol derivatives, triarylphosphin oxide derivatives, polyquinolin and its derivatives, polyquinoxalin and its derivatives, polyfluorene and its derivatives, calcium acetylacetonate, sodium acetate and the like. Inorganic / organic composite materials in which a metal such as cesium is doped with vasophenanthroline (Proceedings of the Society of Polymer Science, Vol. 50, No. 4, p. 660, published in 2001) and the 50th Joint Lecture on Applied Physics. Proceedings of the lecture, No. BCP, TPP, T5MPyTZ, etc. described on page 3, 1402, published in 2003 are also given as examples of electron injection materials, but they can form a thin film necessary for device fabrication, inject electrons from the cathode, and transport electrons. As long as it is a material, it is not particularly limited to these.

Among the electron-injected materials, preferred examples include a metal complex compound, a nitrogen-containing five-membered ring derivative, a silol derivative, and a triarylphosphine oxide derivative. As a preferable metal complex compound, a metal complex of 8-hydroxyquinoline or a derivative thereof is suitable. Specific examples of the metal complex of 8-hydroxyquinoline or a derivative thereof include tris (8-hydroxyquinolinate) aluminum, tris (2-methyl-8-hydroxyquinolinate) aluminum, and tris (4-methyl-8-). Hydroxyquinolinate) Aluminum, Tris (5-Methyl-8-Hydroxyquinolinate) Aluminum, Tris (5-phenyl-8-Hydroxyquinolinate) Aluminum, Bis (8-Hydroxyquinolinate) (1-naphtholat) ) Aluminum, bis (8-hydroxyquinolinate) (2-naphtholat) Aluminum, bis (8-hydroxyquinolinate) (phenorate) aluminum, bis (8-hydroxyquinolinate) (4-cyano-1-naphtholate) ) Aluminum, bis (4-methyl-8-hydroxyquinolinate) (1-naphtholate) aluminum, bis (5-methyl-8-hydroxyquinolinate) (2-naphtholate) aluminum, bis (5-phenyl-8) -Hydroxyquinolinate) (phenorate) aluminum, bis (5-cyano-8-hydroxyquinolinate) (4-cyano-1-naphtholate) aluminum, bis (8-hydroxyquinolinate) chloroaluminum, bis (8) -Aluminum complex compounds such as hydroxyquinolinate (o-cresolate) aluminum, tris (8-hydroxyquinolinate) gallium, tris (2-methyl-8-hydroxyquinolinate) gallium, tris (4-methyl- 8-Hydroxyquinolinate) gallium, tris (5-methyl-8-hydroxyquinolinate) gallium, tris (2-methyl-5-phenyl-8-hydroxyquinolinate) gallium, bis (2-methyl-8) -Hydroxyquinolinate) (1-naphtholate) gallium, bis (2-methyl-8-hydroxyquinolinate) (2-naphtholate) gallium, bis (2-methyl-8-hydroxyquinolinate) (phenorate) gallium , Bis (2-methyl-8-hydroxyquinolinate) (4-cyano-1-naphtholate) gallium, bis (2,4-dimethyl-8-hydroxyquinolinate) (1-naphtholate) gallium, bis (2) , 5-Dimethyl-8-Hydroxyquinolinate) (2-naphtholate) gallium, bis (2-methyl-5-phenyl-8-hydroxyquinolinate) (phenorate) gallium, bis (2-methyl-5-cy) Anno-8-hydroxyquinolinate) (4-cyano-1-naphtholate) gallium, bis (2-methyl-8-hydroxyquinolinate) chlorogallium, bis (2-methyl-8-hydroxyquinolinate) ( In addition to gallium complex compounds such as o-cresolate) gallium, 8-hydroxyquinolinate lithium, bis (8-hydroxyquinolinate) copper, bis (8-hydroxyquinolinate) manganese, bis (10-hydroxybenzo [h] ] Kinolinate) Metal complex compounds such as berylium, bis (8-hydroxyquinolinate) zinc, and bis (10-hydroxybenzo [h] quinolinate) zinc can be mentioned.

Preferred nitrogen-containing five-membered ring derivatives include oxadiazole derivatives, thiazole derivatives, oxadiazole derivatives, thiadiazole derivatives, and triazole derivatives. Specifically, 2,5-bis (1-phenyl) -1, 3,4-Oxadiazole, 2,5-bis (1-phenyl) -1,3,4-thiazole, 2,5-bis (1-phenyl) -1,3,4-oxadiazole, 2- (4) '-Tert-butylphenyl) -5- (4 "-biphenyl) 1,3,4-oxadiazole, 2,5-bis (1-naphthyl) -1,3,4-oxadiazole, 1,4 -Bis [2- (5-phenyloxadiazolyl)] benzene, 1,4-bis [2- (5-phenyloxadiazolyl) -4-tert-butylbenzene], 2- (4'-tert-butyl Benzene) -5- (4 "-biphenyl) -1,3,4-thiadiazole, 2,5-bis (1-naphthyl) -1,3,4-thiadiazole, 1,4-bis [2- (5- (5-) Phenylthia zolyl)] Benzene, 2- (4'-tert-butylphenyl) -5- (4 "-biphenyl) -1,3,4-triazole, 2,5-bis (1-naphthyl) -1, Examples thereof include 3,4-triazole and 1,4-bis [2- (5-phenyltriazolyl)] benzene.

Further, examples of the material that can be used for the electron injection layer include _{inorganic oxides such as zinc oxide (ZnO x} ) and titanium oxide (TiO _x ) and their doped bodies.

Specific examples of particularly preferable oxadiazole derivative, triazole derivative and siror derivative are shown below. In addition, Ph in the table represents a phenyl group.

The photoelectric conversion element may be provided with an ultraviolet blocking layer in order to prevent photodegradation due to ultraviolet rays or the like.
The photoelectric conversion element may be provided with a protective film for the purpose of protecting the photoelectric conversion layer from an external impact. The protective film is, for example, a polymer film such as styrene resin, epoxy resin, acrylic resin, polyurethane, polyimide, polyvinyl alcohol, polyvinylidene fluoride, polyethylene polyvinyl alcohol copolymer, or an inorganic oxide film such as silicon oxide, silicon nitride, or aluminum oxide. It can be composed of a nitride film, a metal plate such as aluminum or a metal foil, or a laminated film thereof. As the material of these protective films, only one kind may be used, or two or more kinds may be used.

It is generally said that semiconductor particles are deteriorated by moisture and oxygen in the air. A barrier membrane may be provided to prevent this. For example, metals or inorganic oxides are preferable, and Ti, Al, Mg, Zr, silicon oxide, aluminum oxide, silicon oxide, aluminum oxide, magnesium oxide, zinc oxide, indium oxide, tin oxide, yttrium oxide, boron oxide, etc. Calcium oxide and the like can be mentioned. There is no particular order in which these various functional films are laminated, and a functional film having these functions may be used.

<Composition for forming a photoelectric conversion layer>
The composition for forming a photoelectric conversion layer of the present invention contains the above-mentioned surface treatment agent and semiconductor particles, and may further contain a solvent. The solvent that may be contained in the composition for forming a photoelectric conversion layer disperses semiconductor particles, and the composition for forming a photoelectric conversion layer of the present invention is placed on a substrate such as a glass substrate so that the dry film thickness becomes a desired film thickness. Used to facilitate application.

(solvent)
The solvent is not particularly limited, and is, for example, 1,2,3-trichloropropane, 1,3-butylene glycol, 1,3-butylene glycol diacetate, 1,4-dioxane, 2-heptanone, 2-methyl-. 1,3-Propanediol, 3,5,5-trimethyl-2-cyclohexen-1-one, 3,3,5-trimethylcyclohexanone, ethyl 3-ethoxypropionate, 3-methyl-1,3-butanediol, 3-methoxy-3-methyl-1-butanol, 3-methoxy-3-methylbutyl acetate, 3-methoxybutanol, 3-methoxybutyl acetate, 4-heptanone, m-xylene, m-diethylbenzene, m-dichlorobenzene, N, N-dimethylacetamide, N, N-dimethylformamide, n-butyl alcohol, n-butylbenzene, n-propyl acetate, N-methylpyrrolidone, toluene, octane, nonane, hexane, o-xylene, o-chlorotoluene , O-diethylbenzene, o-dichlorobenzene, P-chlorotoluene, P-diethylbenzene, sec-butylbenzene, tert-butylbenzene, γ-butyrolactone, water, methanol, ethanol, isopropyl alcohol, tershal tarshalbutanol, isobutyl alcohol, Isophoron, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monoethyl ether, ethylene glycol monoethyl ether acetate, ethylene glycol monotarsial butyl ether, ethylene glycol monobutyl ether, ethylene glycol monobutyl ether acetate, ethylene Glycol monopropyl ether, ethylene glycol monohexyl ether, ethylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate, diisobutyl ketone, diethylene glycol diethyl ether, diethylene glycol dimethyl ether, diethylene glycol monoisopropyl ether, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether, diethylene glycol monobutyl ether Acetate, diethylene glycol monomethyl ether, cyclohexanol, cyclohexanol acetate, cyclohexanone, dipropylene glycol dime Chill Ether, Dipropylene Glycol Methyl Ether Acetate, Dipropylene Glycol Monoethyl Ether, Dipropylene Glycol Monobutyl Ether, Dipropylene Glycol Monopropyl Ether, Dipropylene Glycol Monomethyl Ether, Diacetone Alcohol, Triacetin, Tripropylene Glycol Monobutyl Ether, Tripropylene Glycol Monomethyl ether, propylene glycol diacetate, propylene glycol phenyl ether, propylene glycol monoethyl ether, propylene glycol monoethyl ether acetate, propylene glycol monobutyl ether, propylene glycol monopropyl ether, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, propylene glycol Examples thereof include monomethyl ether propionate, benzyl alcohol, methyl isobutyl ketone, methyl cyclohexanol, n-amyl acetate, n-butyl acetate, isoamyl acetate, isobutyl acetate, propyl acetate, and dibasic acid ester. These solvents may be used alone or in admixture of two or more at any ratio as required.

Hereinafter, the present invention will be specifically described based on examples. Unless otherwise specified, "part" means "part by mass" and "%" means "% by mass". Unless otherwise specified, all measurements were performed at 25 ° C. The structures of the surface treatment agents used in the examples are shown in Tables 6 and 7, and the structures of the surface treatment agents used in the comparative examples are shown in Table 8.

<Preparation of semiconductor particles PbS-0>
First, as a sulfur source solution, 0.40 part of elemental sulfur and 6.0 parts of oleylamine were heated to 120 ° C. in a nitrogen atmosphere in a reaction vessel to form a uniform solution, and then cooled to 25 ° C. Next, as a lead source solution, 0.32 parts of lead chloride and 6.0 parts of oleylamine were heated to 120 ° C. in another reaction vessel under a nitrogen atmosphere. Then, after preparing the lead source solution at 40 ° C., 1.8 parts of the above sulfur source solution was added at once. After reacting for 30 seconds, the container was immersed in an ice bath and rapidly cooled, and then diluted with 13 parts of hexane. After centrifuging (4000 rpm, 5 minutes) to remove unreacted raw materials, add 12 parts of a mixed solution of butanol: methanol = 2: 1 (volume ratio) to precipitate the semiconductor particles and centrifuge (4000 rpm). 5 minutes) to recover the semiconductor particles. Then, 24 parts of a mixture consisting of hexane: oleic acid = 1: 2 (volume ratio) was added, and the mixture was stirred for 30 minutes, centrifuged, and the supernatant was recovered. Semiconductor particle sedimentation, redispersion, and impurity sedimentation are repeated twice, and finally the semiconductor particles are precipitated and vacuum dried, and then adjusted to a solid content concentration of 5% using n-octane to obtain semiconductor particles PbS-0. (Average particle size 3.5 nm).

<Semiconductor particle PbSe-0 synthesis>
As a lead source solution, 0.22 parts of lead oxide, 0.73 parts of oleic acid, and 10 parts of 1-octadecene were heated to 150 ° C. in a reaction vessel under a nitrogen atmosphere. Then, a mixture consisting of 2.5 parts of 1M-trioctylphosphine-selenium solution and 0.028 parts of diphenylphosphine was quickly added, the reaction solution was heated to 180 ° C., kept at 160 ° C., and reacted for 2 minutes. After that, the reaction solution was rapidly cooled. After diluting with 10 parts of hexane, it was precipitated with acetone. The precipitate was washed with acetone 5 times and vacuum dried to obtain semiconductor particles PbSe-0 (average particle size 2.7 nm).

<Semiconductor fine particles Ag ₂ S-0 synthesis>
0.04 parts of silver oleate, 8 parts of octanethiol, and 4 parts of dodecylamine were heated in a reaction vessel at 200 ° C. for 0.5 hours in an Ar atmosphere. After allowing this solution to cool to room temperature, 40 parts of absolute ethanol was added. The obtained mixture was centrifuged and vacuum dried to obtain semiconductor particles Ag ₂ S-0 (average particle size 2.5 nm).

<Preparation of composition for forming photoelectric conversion layer>
<Example 1>
Semiconductor particles PbS-0 were prepared in a toluene solution having a solid content concentration of 1%. After mixing 1 part of the prepared solution and 1 part of the toluene solution of 5% surface treatment agent 1, the mixture was stirred for 12 hours. Purification was performed by the reprecipitation method using toluene and ethanol. The precipitate was vacuum dried to prepare a photoelectric conversion forming composition PbS-1 as a 5% by mass solution of n-octane.

<Examples 2 to 25, Comparative Examples 1 to 7>
_{PbS-2-26, PbSe-1 to 3, and Ag 2} S-1 to 3 were prepared in the same manner as in Example 1 except that the surface treatment agent 1 was changed to the surface treatment agent shown in Table 9. Of these, PbS-2 to 21, PbSe-1 and 2, Ag ₂ S-1 and 2 are the compositions for forming a photoelectric conversion layer of the present invention, and PbS-22-26, PbSe-3, Ag ₂ S. -3 is a composition that is not the composition for forming a photoelectric conversion layer of the present invention.

<Example 101>
(Manufacturing of photoelectric conversion element)
The production and evaluation of the photoelectric conversion element will be described below. The vapor deposition was ^{carried out in a vacuum of 10-6} Torr under the condition that the temperature was not controlled such as heating and cooling of the substrate. The evaluation of the element was measured using a photoelectric conversion element having an element area of 2 mm × 2 mm. First, spin PEDOT / PSS (poly (3,4-ethylenedioxy) -2.5-thiophene / polystyrene sulfonic acid, CLEVIOUS (registered trademark) PVP CH8000 manufactured by Heraeus) on a cleaned glass plate with ITO electrode. It was coated by a coating method and dried at 110 ° C. for 20 minutes to obtain a hole injection layer having a thickness of 35 nm. The composition for forming a photoelectric conversion layer PbS-1 was applied onto the hole injection layer by a spin coating method to form a photoelectric conversion layer having a thickness of 150 nm. Next, a ZnO dispersion N-10 manufactured by Avantama was formed on the photoelectric conversion layer by spin coating to form an electron transport layer having a thickness of 50 nm. Next, aluminum (hereinafter referred to as Al) was vapor-deposited on the electron transport layer to a thickness of 200 nm to form an electrode, and a photoelectric conversion element was obtained.

(Evaluation of photoelectric conversion element)
The durability of the obtained device was evaluated by the method shown below. Durability was calculated by measuring the IV curve before and after storage of the element and calculating the ratio of the measured values. The IV curve of the cell uses xenon lamp white light as a light source (PEC-L01 manufactured by Pexel Technologies Co., Ltd.) and is light at a light intensity (100 mW / cm ² ) equivalent to sunlight (AM1.5). Under a mask with an irradiation area of 0.0363 cm ² (2 mm square), a scanning speed of 0.1 V / sec (0.01 Vstep) and voltage setting using an IV characteristic measuring device (PECK2400-N manufactured by Pexel Technologies Co., Ltd.) The measurement was performed under the conditions of a post-waiting time of 50 msec, a measurement integration time of 50 msec, a start voltage of −0.1 V, and an end voltage of 1.1 V. For durability, the IV curve was measured before storage (immediately after device fabrication) and after storage of the photoelectric conversion element for 4 days under the conditions of shading, 25 ° C., and humidity of 60%, and before storage (immediately after device fabrication). It was calculated as the ratio of the conversion efficiency after storage to the conversion efficiency of.
(Evaluation criteria)
⊚: Ratio 95% or more: Good ○: Ratio 90% or more and less than 95%: Practically usable △: Ratio 80% or more and less than 90%: Practically unusable ×: Ratio less than 80%: Defective

<Examples 102 to 125>
The photoelectric conversion element was used in the same manner as in Example 1 except that PbS-2 to 21, PbSe-1, 2, and Ag _{2 S-1, 2 were used instead of PbS-1 used in Example 101.} Each was prepared and evaluated. The results are shown in Table 10.

<Comparative Examples 101-107>
Instead of PbS-1 used in Example 101, prepared PbS-22~26, PbSe-3, except for using Ag ₂ S-3, respectively, the same procedure as in Example 101 a photoelectric conversion element, respectively, evaluation did. The results are shown in Table 10.

It was clarified that all of the photoelectric conversion elements (Examples 101 to 125) of the present invention are superior in durability over time to the elements of the comparative examples. The surface treatment agents 1 to 21 used in Examples 101 to 125 are capable of adsorbing a carboxyl group or a sulfanil group to the surface of semiconductor particles and have many aromatic rings in the molecule. As a result, it is speculated that the shielding effect of the aromatic ring suppresses the deterioration caused by the attack on the surface of the semiconductor particles by oxygen, water, etc., and improves the durability of the device. In Examples 101 to 110, 112 to 114, and 16 to 125, particularly high durability was observed. It is presumed that the surface treatment agents 1 to 10, 12 to 14, 16 to 21 have a diphenylamino skeleton, and in particular, the shielding effect works effectively.

Claims (5)

A photoelectric conversion element having a photoelectric conversion layer between a pair of electrodes, wherein the photoelectric conversion layer contains a surface treatment agent and semiconductor particles, and the surface treatment agent is a diarylamine skeleton, a quinoline skeleton and an indole. A photoelectric conversion element having at least one partial structure selected from the group consisting of a skeleton and at least one group selected from the group consisting of a carboxyl group and a sulfanyl group. The photoelectric conversion element according to claim 1, wherein the surface treatment agent has a structure represented by the following general formula (1), general formula (2) or general formula (3).

General formula (1)

[In the general formula (1), X ¹ is a hydrogen atom, an alkyl group which may have a substituent, an aryl group which may have a substituent, or an acyl group which may have a substituent. , R ^{1 to} R ⁸ are independently hydrogen atom, an alkyl group which may have a substituent, an aryl group which may have a substituent, an alkoxy group which may have a substituent, and a substituent. An aryloxy group which may have a group, an acyl group which may have a substituent, an amino group which may have a substituent, a (poly) organosiloxy group which may have a substituent, and a carboxyl group. Alternatively, it is a sulfanyl group, and ^{at least one of X 1} and R ^{1 to} R ⁸ is a carboxyl group, a sulfanyl group, a group having a carboxyl group, or a group having a sulfanyl group. ]

General formula (2)

[In the general formula (2), R ^{11 to} R ²⁵ each independently have a hydrogen atom, an alkyl group which may have a substituent, an aryl group which may have a substituent, and a substituent. May have an alkoxy group, an aryloxy group which may have a substituent, an acyl group which may have a substituent, a (poly) organosiloxy group which may have a substituent, a nitro group, and a substituent. It is an amino group, a carboxyl group or a sulfanyl group which may have ^{, and at least one of R 11 to} R ²⁵ is a carboxyl group, a sulfanyl group, a group having a carboxyl group or a group having a sulfanyl group. ]

General formula (3)

[In the general formula (3), X ² has a hydrogen atom, an alkyl group which may have a substituent, an aryl group which may have a substituent (excluding a phenyl group), or a substituent. R ^{26 to} R ³⁵ may independently have a hydrogen atom, an alkyl group which may have a substituent, an aryl group which may have a substituent, and a substituent. It has an alkoxy group which may have a substituent, an aryloxy group which may have a substituent, a (poly) organosiloxy group which may have a substituent, an amino group which may have a substituent, and a substituent. It is also a good acyl group, carboxyl group or sulfanyl group, and ^{at least one of X 2} and R ^{26 to} R ³⁵ is a carboxyl group, a sulfanyl group, a group having a carboxyl group or a group having a sulfanyl group. ] The photoelectric conversion element according to claim 1 or 2, wherein the semiconductor particles can absorb electromagnetic waves having a wavelength of 700 to 2500 nm. Semiconductor particles, PbS, PbSe and Ag ₂ is selected from the group consisting of S comprising one or more kinds claims 1-3 photoelectric conversion device as set forth in any one. It contains a surface treatment agent and semiconductor particles having at least one partial structure selected from the group consisting of a diarylamine skeleton, a quinoline skeleton and an indole skeleton, and at least one group selected from the group consisting of a carboxyl group and a sulfanyl group. A composition for forming a photoelectric conversion layer.