JP6730037B2 - Solar cells and organic semiconductor materials - Google Patents

Description

The present invention relates to a solar cell that has sputtering resistance, high photoelectric conversion efficiency, and can withstand high temperature and high humidity, and an organic semiconductor material.

BACKGROUND ART Conventionally, a photoelectric conversion element including a laminated body in which an N-type semiconductor layer and a P-type semiconductor layer are arranged between opposing electrodes has been developed. In such a photoelectric conversion element, a photocarrier is generated by photoexcitation, and an electron moves in the N-type semiconductor and a hole moves in the P-type semiconductor, thereby generating an electric field.

Most of the photoelectric conversion elements currently in practical use are inorganic solar cells manufactured using an inorganic semiconductor such as silicon. However, since inorganic solar cells are expensive to manufacture and difficult to increase in size, and the range of use is limited, organic solar cells manufactured using organic semiconductors instead of inorganic semiconductors are receiving attention. ..

In most of the organic solar cells, fullerenes are used. Fullerenes are known to act mainly as N-type semiconductors. For example, Patent Document 1 describes a semiconductor heterojunction film formed using an organic compound that becomes a P-type semiconductor and fullerenes. However, in organic solar cells manufactured using fullerenes, it is known that the cause of deterioration is fullerenes (for example, refer to Non-Patent Document 1), and a material replacing fullerenes is required.

JP, 2006-344794, A

Reese et al. , Adv. Funct. Mater. , 20, 3476-3483 (2010)

An object of the present invention is to provide a solar cell having high sputtering resistance, high photoelectric conversion efficiency, and withstanding high temperature and high humidity, and an organic semiconductor material.

The present invention has an electrode, a transparent electrode, a photoelectric conversion layer arranged between the electrode and the transparent electrode, and a hole transport layer arranged between the photoelectric conversion layer and the transparent electrode. a solar cell, the photoelectric conversion layer has the general formula R-M-X 3 _(where, R represents an organic molecule, M is a metal atom, X is a halogen atom or a chalcogen atom.) the organic-inorganic represented by The hole transport layer contains a compound having a phthalocyanine skeleton, and the compound having a phthalocyanine skeleton contains at least one selected from the group consisting of an alkyl group, an alkoxy group, a halogen group, and an aromatic group. It is a solar cell having a substituent.
Hereinafter, the present invention will be described in detail.

The present inventors, in a solar cell having an electrode, a transparent electrode, and a photoelectric conversion layer arranged between the electrode and the transparent electrode, using a specific organic-inorganic perovskite compound for the photoelectric conversion layer, further It was examined to dispose a hole transport layer between the photoelectric conversion layer and the transparent electrode. By using the organic-inorganic perovskite compound, improvement in photoelectric conversion efficiency of the solar cell can be expected. Further, by disposing a hole transport layer between the photoelectric conversion layer and the transparent electrode, improvement in photoelectric conversion efficiency can be expected.
On the other hand, in an organic solar cell, it is common to form a transparent electrode by a sputtering method or the like. However, when the transparent electrode is formed by the sputtering method or the like, the inventors of the present invention damage the hole transport layer depending on the kind of the material of the hole transport layer such as polythiophene and cause deterioration of the solar cell (initial deterioration). Therefore, it was found that high photoelectric conversion efficiency cannot be obtained. With respect to this problem, the present inventors, by using a specific organic-inorganic perovskite compound for the photoelectric conversion layer, and by using a specific material for the hole transport layer, the photoelectric conversion efficiency is increased, and by a sputtering method or the like. It has been found that the hole transport layer is not damaged even if the transparent electrode is directly formed on the hole transport layer (that is, it has sputtering resistance). Furthermore, the present inventors have found that by using such a specific hole transport layer, the durability which can withstand even under high temperature and high humidity can be improved, and the present invention has been completed.

The solar cell of the present invention has an electrode, a transparent electrode, and a photoelectric conversion layer arranged between the electrode and the transparent electrode.
In the present specification, the term “layer” means not only a layer having a clear boundary but also a layer having a concentration gradient in which the contained element gradually changes. The elemental analysis of the layer can be performed by, for example, performing FE-TEM/EDS line analysis measurement of the cross section of the solar cell and confirming the elemental distribution of the specific element. Further, in the present specification, the layer means not only a flat thin film-like layer but also a layer capable of forming a complicated and complicated structure together with other layers.

Materials for the electrodes and the transparent electrodes are not particularly limited, and conventionally known materials can be used.
Examples of the electrode material include metals such as gold, silver, titanium, and copper, sodium, sodium-potassium alloy, lithium, magnesium, aluminum, magnesium-silver mixture, magnesium-indium mixture, aluminum-lithium alloy, Al/Al ₂ O. ₃ mixtures, Al/LiF mixtures, etc. are mentioned. Examples of transparent electrode materials include CuI, ITO (indium tin oxide), SnO ₂ , AZO (aluminum zinc oxide), IZO (indium zinc oxide), GZO (gallium zinc oxide), FTO (fluorine-doped tin oxide). ), conductive transparent materials such as ATO (antimony-doped tin oxide), conductive transparent polymers, and the like. These materials may be used alone or in combination of two or more. The electrode may be a transparent electrode. Further, the electrode may be a cathode or an anode. The transparent electrode is often a patterned electrode.

The photoelectric conversion layer has the general formula R-M-X 3 _(where, R represents an organic molecule, M is a metal atom, X is a halogen atom or a chalcogen atom.) Containing an organic-inorganic perovskite compound represented by.
By using the organic-inorganic perovskite compound in the photoelectric conversion layer, the photoelectric conversion efficiency of the solar cell can be improved.

The above R is an organic molecule and is preferably represented by C ₁ N _m H _n (where l, m and n are all positive integers).
Specifically, R is, for example, methylamine, ethylamine, propylamine, butylamine, pentylamine, hexylamine, dimethylamine, diethylamine, dipropylamine, dibutylamine, dipentylamine, dihexylamine, trimethylamine, triethylamine, tripropyl. Amine, tributylamine, tripentylamine, trihexylamine, ethylmethylamine, methylpropylamine, butylmethylamine, methylpentylamine, hexylmethylamine, ethylpropylamine, ethylbutylamine, imidazole, azole, pyrrole, aziridine, azirine, Azetidine, azeto, imidazoline, carbazole, aniline, pyridine, methylcarboxyamine, ethylcarboxyamine, propylcarboxyamine, butylcarboxyamine, pentylcarboxyamine, hexylcarboxyamine, formamidinium, guanidine ion (for example, methylammonium (CH ₃ NH ₃ ) etc.) and phenethyl ammonium. Among them, methylamine, ethylamine, propylamine, butylamine, pentylamine, hexylamine, aniline, pyridine, propylcarboxyamine, butylcarboxyamine, pentylcarboxyamine, formamidinium, guanidine ion and phenethylammonium are preferable, and methylamine More preferred are ions of ethylamine, propylamine, pentylcarboxyamine, formamidinium and guanidine.

The M is a metal atom, and for example, lead, tin, zinc, titanium, antimony, bismuth, nickel, iron, cobalt, silver, copper, gallium, germanium, magnesium, calcium, indium, aluminum, manganese, chromium, molybdenum, Examples include europium. Of these, lead and tin are preferable from the viewpoint of overlapping electron orbits. These metal atoms may be used alone or in combination of two or more.

The above X is a halogen atom or a chalcogen atom, and examples thereof include chlorine, bromine, iodine, sulfur and selenium. These halogen atoms or chalcogen atoms may be used alone or in combination of two or more. Among them, the halogen atom is preferable since the organic-inorganic perovskite compound is likely to be soluble in the organic solvent by containing halogen in the structure, and it becomes possible to apply to an inexpensive printing method or the like. Furthermore, iodine is more preferable because the energy band gap of the organic-inorganic perovskite compound is narrowed.

The organic-inorganic perovskite compound preferably has a cubic structure in which a metal atom M is arranged in the body center, an organic molecule R is arranged in each vertex, and a halogen atom or a chalcogen atom X is arranged in the face center. FIG. 1 shows an example of a crystal structure of an organic-inorganic perovskite compound having a cubic structure in which a metal atom M is arranged in the body center, an organic molecule R is arranged at each vertex, and a halogen atom or a chalcogen atom X is arranged in the face center. It is a schematic diagram. Although details are not clear, since the orientation of the octahedron in the crystal lattice can be easily changed by having the above structure, the electron mobility in the organic-inorganic perovskite compound becomes high, and the photoelectric conversion of the solar cell is increased. It is estimated that the conversion efficiency will be improved.

The organic-inorganic perovskite compound is preferably a crystalline semiconductor. The crystalline semiconductor means a semiconductor whose X-ray scattering intensity distribution can be measured and whose scattering peak can be detected. When the organic-inorganic perovskite compound is a crystalline semiconductor, the mobility of electrons in the organic-inorganic perovskite compound is increased and the photoelectric conversion efficiency of the solar cell is improved.

Also, the crystallinity can be evaluated as an index of crystallization. The crystallinity is obtained by separating the scattering peaks derived from the crystalline material detected by X-ray scattering intensity distribution measurement and the halo derived from the amorphous portion by fitting, obtaining the respective intensity integral values, and measuring the crystal of the whole. It can be obtained by calculating the percentage from the ratio of the parts.
A preferable lower limit of the crystallinity of the organic-inorganic perovskite compound is 30%. When the crystallinity is 30% or more, the mobility of electrons in the organic-inorganic perovskite compound is high, and the photoelectric conversion efficiency of the solar cell is improved. A more preferable lower limit of the crystallinity is 50%, and a still more preferable lower limit thereof is 70%.
Examples of methods for increasing the crystallinity of the organic-inorganic perovskite compound include thermal annealing, irradiation with intense light such as laser, and plasma irradiation.

The preferable lower limit of the thickness of the photoelectric conversion layer is 5 nm, and the preferable upper limit thereof is 1000 nm. When the thickness is 5 nm or more, light can be sufficiently absorbed. When the thickness is 1000 nm or less, the generated charges can be transported to each electrode. A more preferable lower limit of the thickness is 10 nm, a more preferable upper limit thereof is 700 nm, a still more preferable lower limit thereof is 15 nm, and a still more preferable upper limit thereof is 500 nm.

The solar cell of the present invention has a hole transport layer arranged between the photoelectric conversion layer and the transparent electrode.
The hole transport layer contains a compound having a phthalocyanine skeleton. Generally, a solar cell having a hole transport layer suppresses recombination of photocarriers at the interface between the photoelectric conversion layer and the transparent electrode, and further increases the photoelectric conversion efficiency by reducing the interface resistance value. be able to. However, when the transparent electrode is formed by the sputtering method or the like, the hole transport layer may be damaged depending on the kind of the material of the hole transport layer such as polythiophene, which may cause deterioration (initial deterioration) of the solar cell and high photoelectric conversion efficiency. Can't get On the other hand, in the solar cell of the present invention, since the hole transport layer contains a compound having a phthalocyanine skeleton, even if the transparent electrode is directly formed on the hole transport layer by a sputtering method or the like (that is, the above Sputtering resistance can be improved (even if the hole transport layer and the transparent electrode are adjacent to each other). Furthermore, by including the compound having the phthalocyanine skeleton, the durability of the solar cell, which can withstand even under high temperature and high humidity, can be improved.

The compound having a phthalocyanine skeleton has at least one kind of substituent selected from the group consisting of an alkyl group, an alkoxy group, a halogen group, and an aromatic group. When the compound having the phthalocyanine skeleton has the substituent, it becomes difficult for the compound having the phthalocyanine skeleton to dissolve the organic-inorganic perovskite compound. Moreover, since the compound having the phthalocyanine skeleton becomes soluble in the organic solvent, the hole transport layer can be formed by an inexpensive and simple coating method. These substituents may be used alone or in combination of two or more. Above all, the substituent is preferably an alkyl group or an aromatic group from the viewpoint of increasing the solubility in an organic solvent. The substitution site of the above substituent is not particularly limited, and may be the α-position or the β-position of the phthalocyanine skeleton. The number of substitutions of the above-mentioned substituents is not particularly limited and may be plural. When an aromatic group is used as the above-mentioned substituent, a part of the above-mentioned aromatic group may be substituted with a substituent.

The compound having a phthalocyanine skeleton may have a central metal. Examples of the central metal include zinc, copper, nickel, magnesium, cobalt, iron, titanium, lead, indium, beryllium, molybdenum, palladium, sodium, lithium, silver, tin, gallium, germanium, aluminum and manganese. .. Among them, the central metal is preferably zinc, nickel, or palladium, and more preferably palladium, because the photoelectric conversion efficiency becomes higher.

Specific examples of the compound having a phthalocyanine skeleton include metal-free phthalocyanine, zinc phthalocyanine, zinc phthalocyanine having a t-butyl group, palladium phthalocyanine having a t-butyl group, and palladium phthalocyanine having a phenyl group.

The hole transport layer preferably contains, in addition to the compound having a phthalocyanine skeleton, an ionic compound in which a phthalocyanine compound cation represented by the following general formula (1) and a fluorine-containing compound anion are combined. By containing such an ionic compound, the solar cell of the present invention can easily achieve both photoelectric conversion efficiency and durability.
A material for an organic semiconductor, which comprises an ionic compound in which a phthalocyanine compound cation represented by the following general formula (1) and a fluorine-containing compound anion are combined, is also one aspect of the present invention.

式（１）中、Ｘは水素又は置換基を表し、Ｘの中の少なくとも１つは、アルキル基、アルコキシ基、ハロゲン基、又は芳香族基である。

In formula (1), X represents hydrogen or a substituent, and at least one of X is an alkyl group, an alkoxy group, a halogen group, or an aromatic group.

The fluorine-containing anion is not particularly limited as long as it can form a stable ionic compound with the phthalocyanine compound cation represented by the general formula (1). Among them, an anion represented by the following formula (2-1), an anion represented by the following formula (2-2), an anion represented by the following formula (2-3), and a following formula (2-4) An anion represented by the following formula, an anion represented by the following formula (2-5), or an anion represented by the following formula (2-6) is preferable.

一般式（２−１）〜（２−３）中、Ｒ^１〜Ｒ^３は、一部又は全てがフッ素で置換されている炭素数１〜５のアルキル基を表し、一般式（２−１）においては、一方のＲ^１と他方のＲ^１とが結合して環状構造を有してもよい。

In general formulas (2-1) to (2-3), R ^{1 to} R ³ represent an alkyl group having 1 to 5 carbon atoms, part or all of which is substituted with fluorine, and are represented by general formula (2-1) In (), one R ¹ and the other R ¹ may be bonded to each other to have a cyclic structure.

The hole transport layer may contain another hole transport material in addition to the compound having the phthalocyanine skeleton. Examples of the other hole transport material include compounds having a thiophene skeleton such as poly(3-alkylthiophene). Further, for example, a conductive polymer having a polyparaphenylenevinylene skeleton, a polyvinylcarbazole skeleton, a polyaniline skeleton, a polyacetylene skeleton, or the like can be given. Furthermore, for example, compounds having a porphyrin skeleton such as a pentacene skeleton, a benzoporphyrin skeleton, a spirobifluorene skeleton, a triphenylamine skeleton, and the like can be given. The ratio of the compound having the phthalocyanine skeleton in the hole transport layer is not particularly limited in terms of increasing sputtering resistance and durability, but the lower limit is preferably 70 mol% or more, more preferably 80 mol% or more, 90 mol% or more is more preferable, and 100 mol% is particularly preferable.
Further, the method for forming the hole transport layer is not particularly limited, and the hole transport layer material containing the compound having the phthalocyanine skeleton may be laminated using a dry process such as a vacuum deposition method. From the viewpoint of conforming to the shape of the photoelectric conversion layer, a wet process of laminating by applying a solution in which the hole transport layer material containing the compound having a phthalocyanine skeleton is dissolved in an organic solvent or the like is preferable.

The preferable lower limit of the thickness of the hole transport layer is 1 nm, and the preferable upper limit thereof is 2000 nm. When the thickness is 1 nm or more, electrons can be sufficiently blocked. When the thickness is 2000 nm or less, resistance during hole transportation is less likely to occur, and photoelectric conversion efficiency increases. The more preferable lower limit of the thickness is 3 nm, the more preferable upper limit thereof is 500 nm, the still more preferable lower limit thereof is 5 nm, and the still more preferable upper limit thereof is 200 nm.

The hole transport layer may be a single layer or multiple layers. In the case of a multilayer, it is preferable that the compound having the phthalocyanine skeleton is arranged in the outermost layer of the hole transport layer from the viewpoint of further improving the sputtering resistance. The preferred lower limit of the thickness of the outermost layer is 1 nm, the preferred upper limit is 100 nm, the more preferred lower limit is 5 nm, and the more preferred upper limit is 70 nm. Examples of the hole transport layer material included in the layers other than the outermost layer include compounds having a thiophene skeleton such as poly(3-alkylthiophene). Further, for example, a conductive polymer having a polyparaphenylenevinylene skeleton, a polyvinylcarbazole skeleton, a polyaniline skeleton, a polyacetylene skeleton, or the like can be given. Further, examples thereof include compounds having a porphyrin skeleton such as a naphthalocyanine skeleton, a pentacene skeleton, and a benzoporphyrin skeleton.

In the solar cell of the present invention, an electron transport layer may be arranged between the electrode and the photoelectric conversion layer.
The material of the electron transport layer is not particularly limited, and examples thereof include N-type conductive polymers, N-type low molecular weight organic semiconductors, N-type metal oxides, N-type metal sulfides, alkali metal halides, alkali metals, surface active agents. Specific examples include agents such as cyano group-containing polyphenylene vinylene, boron-containing polymers, bathocuproine, bathophenanthrene, hydroxyquinolinato aluminum, oxadiazole compounds, benzimidazole compounds, naphthalenetetracarboxylic acid compounds, perylene derivatives, Examples thereof include phosphine oxide compounds, phosphine sulfide compounds, fluoro group-containing phthalocyanines, titanium oxide, zinc oxide, indium oxide, tin oxide, gallium oxide, tin sulfide, indium sulfide and zinc sulfide.

The electron transport layer may be composed of only a thin film electron transport layer, but preferably includes a porous electron transport layer. In particular, when the photoelectric conversion layer is a composite film containing the organic-inorganic perovskite compound, a more complicated composite film (more complicated intricate structure) is obtained, and the photoelectric conversion efficiency is increased, so that the porous film is porous. It is preferable that the composite film is formed on the electron transporting layer.

The preferable lower limit of the thickness of the electron transport layer is 1 nm, and the preferable upper limit thereof is 2000 nm. If the thickness is 1 nm or more, holes can be sufficiently blocked. When the thickness is 2000 nm or less, resistance during electron transport is less likely to occur, and photoelectric conversion efficiency is increased. A more preferable lower limit of the thickness of the electron transport layer is 3 nm, a more preferable upper limit thereof is 1000 nm, a still more preferable lower limit thereof is 5 nm, and a still more preferable upper limit thereof is 500 nm.

The solar cell of the present invention may further have a substrate and the like. The substrate is not particularly limited, and examples thereof include a transparent glass substrate such as soda lime glass and non-alkali glass, a ceramic substrate, and a transparent plastic substrate.

In the solar cell of the present invention, as described above, the electrode is formed on the substrate arranged as necessary, the electron transport layer, the photoelectric conversion layer, the hole transport layer, and the transparent electrode are formed if necessary. The laminated body thus formed may be sealed with a sealing material. The sealing material is not particularly limited as long as it has a gas barrier property, and examples thereof include thermosetting resins, thermoplastic resins, and inorganic materials.

Examples of the thermosetting resin and thermoplastic resin include epoxy resin, acrylic resin, silicon resin, phenol resin, melamine resin, urea resin, butyl rubber, polyester, polyurethane, polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyvinyl alcohol, poly Examples thereof include vinyl acetate, ABS resin, polybutadiene, polyamide, polycarbonate, polyimide and polyisobutylene.

Examples of the inorganic material include oxides, nitrides or oxynitrides of Si, Al, Zn, Sn, In, Ti, Mg, Zr, Ni, Ta, W, Cu or alloys containing two or more of these. .. Among them, oxides, nitrides or oxynitrides of metal elements containing both metal elements Zn and Sn are preferable in order to impart water vapor barrier properties and flexibility to the above-mentioned sealing material.

The thermosetting resin and/or the thermoplastic resin may be disposed between the inorganic material and the laminate to flatten the outermost surface of the laminate.

Further, in the solar cell of the present invention, the sealing material may be covered with other materials such as a glass plate, a resin film, a resin film coated with an inorganic material, and a metal foil. That is, the solar cell of the present invention may have a configuration in which the layered product and the other materials are sealed, filled, or adhered with the sealing material. Thereby, even if there is a pinhole in the encapsulant, the water vapor can be sufficiently blocked, and the durability of the solar cell can be further improved.

The method for producing the solar cell of the present invention is not particularly limited, and, for example, the electrode on the substrate arranged as necessary, the electron transport layer if necessary, the photoelectric conversion layer, the hole transport layer and Examples include a method in which the transparent electrode is formed in this order to produce a laminated body, and then the laminated body is sealed with the sealing material.

The method for forming the photoelectric conversion layer is not particularly limited, and examples thereof include a vacuum vapor deposition method, a sputtering method, a vapor phase reaction method (CVD), an electrochemical deposition method, and a printing method. Above all, by adopting the printing method, a solar cell capable of exhibiting high photoelectric conversion efficiency can be easily formed in a large area. Examples of the printing method include a spin coating method and a casting method, and examples of the printing method include a roll-to-roll method.

Of the encapsulant, the method of sealing the laminate with the thermosetting resin and the thermoplastic resin is not particularly limited, for example, a method of sealing the laminate using a sheet-like encapsulant, A method of applying a sealing material solution in which an encapsulating material is dissolved in an organic solvent to the above-mentioned laminated body, and after applying a liquid monomer serving as an encapsulating material to the above-mentioned laminated body, crosslinking or polymerization of the liquid monomer by heat or UV. Examples of the method include a method of applying the heat, a method of applying heat to the encapsulating material to melt it, and then cooling it.

Among the encapsulating materials, as a method of covering the laminate with the inorganic material, a vacuum vapor deposition method, a sputtering method, a vapor phase reaction method (CVD), and an ion plating method are preferable. Among them, the sputtering method is preferable for forming a dense layer, and the DC magnetron sputtering method is more preferable among the sputtering methods.
In the above-mentioned sputtering method, an inorganic layer made of an inorganic material can be formed by using a metal target and oxygen gas or nitrogen gas as a raw material and depositing the raw material on the above-mentioned laminate to form a film.

ADVANTAGE OF THE INVENTION According to this invention, the solar cell which has sputtering resistance, has high photoelectric conversion efficiency, and can withstand high temperature and high humidity, and an organic-semiconductor material can be provided.

It is a schematic diagram which shows an example of the crystal structure of an organic-inorganic perovskite compound.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

( Reference example 1 )
(Production of solar cell)
The titanium substrate was ultrasonically cleaned using pure water, acetone, and methanol in this order for 10 minutes, respectively, and then dried.
A titanium isopropoxide ethanol solution adjusted to 2% by weight was applied on the surface of a titanium substrate by a spin coating method, and then baked at 400° C. for 10 minutes to form a thin-film electron transport layer having a thickness of 20 nm. Further, a titanium oxide paste containing polyisobutyl methacrylate as an organic binder, titanium oxide (average particle size 25 nm) and ethanol was applied on the thin film electron transport layer by spin coating, and then at 500° C. for 10 minutes. Firing was performed to form a porous electron transport layer having a thickness of 500 nm.
Then, as a solution for forming an organic-inorganic perovskite compound, CH ₃ NH ₃ I and PbCl ₂ were dissolved at a molar ratio of 1:1 using N,N-dimethylformamide as a solvent, and the total weight concentration of CH ₃ NH ₃ I and PbCl ₂ was changed. It was adjusted to 20%. This solution was laminated on the electron transport layer by spin coating to form a photoelectric conversion layer. Further, nickel phthalocyanine (central metal Ni, α-position=H, β-position=t-butyl group) was laminated on the photoelectric conversion layer as a hole-transporting layer to a thickness of 100 nm by a coating method using chlorobenzene as a solvent. On the hole transport layer, an ITO target doped with 5% tin was used, Ar gas containing O ₂ (5%) was used, and a pressure of 0.5 Pa was used as a transparent electrode with a thickness of 100 nm ITO as a transparent electrode. A film was formed to obtain a solar cell. In addition, in the present Reference Examples, Examples, and Comparative Examples, the substituents of phthalocyanine were all 4-substituted.

( Reference Examples 2-6, Comparative Examples 1-5)
A solar cell was obtained in the same manner as in Reference Example 1 except that the material used for the hole transport layer (a compound having a phthalocyanine skeleton or a compound other than the compound having a phthalocyanine skeleton) was changed to the material shown in Table 1. It was In Comparative Examples 4 and 5, solar cells could not be obtained because the compound having a phthalocyanine skeleton did not dissolve in the solvent and coating could not be performed.

(Example 7)
0.25 g of palladium phthalocyanine (central metal Pd, α-position=H, β-position=t-butyl group) and 0.17 g of silver-bis(trifluoromethylsulfonyl)imide (Ag-TFSI, manufactured by Aldrich) dichloromethane. Was dissolved in 25 mL and stirred at 500 rpm. Thereafter, the precipitate was separated through a 1 μm mesh, and the recovered solution was concentrated by an evaporator to obtain an ionic compound of palladium phthalocyanine cation and TFSI anion. Next, 1 mg of the obtained ionic compound and 9 mg of the above-mentioned palladium phthalocyanine were dissolved in 500 μL of chlorobenzene, and the solution was applied by spin coating to form a hole transport layer containing 10% of the ionic compound. A film was formed by the same method as in Reference Example 1 except for the hole transport layer to obtain a solar cell.
It should be noted that the palladium phthalocyanine and TFSI may form an ionic bond by measuring the absorption spectrum and comparing the absorption spectrum with that not forming an ionic bond to confirm that the absorption is shifted by a long wavelength. confirmed.

(Example 8)
A solar cell was obtained in the same manner as in Example 7 except that Ag-NFSI (bis(nonafluorobutanesulfonyl)imide, manufactured by Mitsubishi Materials Electronics Corporation) was used instead of Ag-TFSI.

(Example 9)
A solar cell was obtained in the same manner as in Example 8 except that the substituent on the β-position of palladium phthalocyanine was changed to an alkoxy group (cyclohexyloxy group).

<Evaluation>
The following evaluations were performed on the solar cells obtained in the examples , reference examples and comparative examples. The results are shown in Table 2. Comparative Examples 4 and 5 were not evaluated because no solar cell was obtained.

(1) Photoelectric conversion efficiency A power source (KEITHLEY, 236 model) was connected between the obtained solar cell electrodes, and the photoelectric conversion efficiency was calculated using a solar simulation (Yamashita Denso Co., Ltd.) with an intensity of 100 mW/cm ^2. It was measured. The photoelectric conversion efficiency of the solar cells obtained in Comparative Example 1 was set to 1.0, and the photoelectric conversion efficiency of the solar cells obtained in Reference Examples 1 to 6, Examples 7 to 9 and Comparative Examples 2 and 3 was standardized. Turned into

(2) Durability Acrylic resin was coated on the obtained solar cell, SiO ₂ was further laminated by a sputtering method, and after sealing, it was placed under conditions of 85 RH% and 85° C. for 48 hours for durability test. went. Before and after the durability test, a power supply (KEITHLEY, 236 model) is connected between the electrodes of the solar cell, and a solar simulation (manufactured by Yamashita Denso Co., Ltd.) with a strength of 100 mW/cm ² is used. Was measured, and the value of photoelectric conversion efficiency after durability test/photoelectric conversion efficiency before durability test was determined.
◯: The value of photoelectric conversion efficiency after durability test/photoelectric conversion efficiency before durability test is 0.8 or more×: photoelectric conversion efficiency after durability test/value of photoelectric conversion efficiency before durability test is 0. Less than 8

ADVANTAGE OF THE INVENTION According to this invention, the solar cell which has sputtering resistance and high photoelectric conversion efficiency, and can withstand high temperature and high humidity, and the material for organic semiconductors can be provided.

Claims (4)

A solar cell having an electrode, a transparent electrode, a photoelectric conversion layer arranged between the electrode and the transparent electrode, and a hole transport layer arranged between the photoelectric conversion layer and the transparent electrode. hand,
The photoelectric conversion layer has the general formula R-M-X 3 _(where, R represents an organic molecule, M is a metal atom, X is a halogen atom or a chalcogen atom.) An organic-inorganic perovskite compound represented by,
The hole transporting layer comprises a compound having a phthalocyanine skeleton, possess the compound having a phthalocyanine skeleton is an alkyl group, an alkoxy group, at least one substituent selected from the group consisting of halogen groups, and aromatic groups A solar cell , wherein the hole transport layer contains an ionic compound in which a phthalocyanine compound cation represented by the following general formula (1) and a fluorine-containing compound anion are combined .

In formula (1), X represents hydrogen or a substituent, and at least one of X is an alkyl group, an alkoxy group, a halogen group, or an aromatic group. The solar cell according to claim 1, wherein the compound having a phthalocyanine skeleton has a central metal, and the central metal is zinc, nickel or palladium. The thickness of the hole transport layer is 1 nm or more and 2000 nm or less, and the solar cell according to claim 1 or 2 . An organic semiconductor material comprising an ionic compound in which a phthalocyanine compound cation represented by the following general formula (1) and a fluorine-containing compound anion are bonded.

In formula (1), X represents hydrogen or a substituent, and at least one of X is an alkyl group, an alkoxy group, a halogen group, or an aromatic group.

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