Composition, method for preparing composition and photoelectric conversion element

Abstract

A composition is provided that improves the dispersion stability and the photoelectric conversion efficiency of a photoelectric conversion element using the composition. The composition according to the invention comprises: a pigment as a cyclic conjugated compound in which a plurality of pyrrole rings are linked by conjugated bonds; a dispersant; a resin; and a solvent. The composition is characterized in that the dispersant is a calixarene compound represented by formula [A], and the mass of the dispersant in the composition is more than 0.20 times the mass of the resin in the composition.

Description

Technical Field

[0001] This invention relates to compositions, methods for preparing compositions, and photoelectric conversion elements. Background Technology

[0002] To address the depletion of fossil fuels and the environmental problems caused by their use, research is actively underway on renewable and clean alternative energy sources such as solar, wind, and hydropower. In particular, there is increasing interest in solar cells, which directly convert sunlight into electricity. As used in this paper, "solar cell" refers to a battery that generates current and voltage using the photovoltaic effect, in which light energy is absorbed from sunlight to produce electrons and holes.

[0003] Currently, NP diode-based monocrystalline silicon (Si) solar cells with a light conversion efficiency exceeding 20% ​​are widely known and practically used in solar power generation. However, solar cells require high-temperature processing steps, and the materials themselves are expensive, resulting in high cost per unit of electricity. Furthermore, there are supply issues regarding silicon resources.

[0004] Meanwhile, solar cells using organic materials (hereinafter also referred to as "organic solar cells") do not require high-temperature processing steps and can be manufactured using sheet substrates in a so-called roll-to-roll manner. Therefore, cost reduction is expected. However, for the practical application of organic solar cells, further improvements in power generation efficiency and durability are desired. In particular, the development of perovskite-type solar cells, which incorporate crystals with a perovskite structure as the photoelectric conversion layer, is being promoted for practical application because these cells exhibit excellent photoelectric conversion characteristics. For example, Patent Document 1 describes a technique that improves photoelectric conversion efficiency by forming a layer containing a phthalocyanine compound between a hole transport layer and the perovskite. Patent Document 2 describes a technique that enables long-term maintenance of conversion efficiency by forming a layer containing a phthalocyanine compound and an aromatic ring compound with hydroxyl groups between a hole transport layer and the perovskite.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2022-168820

[0008] Patent Document 2: Japanese Patent Application Publication No. 2024-60579 Summary of the Invention

[0009] The problem the invention aims to solve

[0010] According to research conducted by the inventors of this invention, there is still room for improvement in terms of the dispersion stability of the compositions described in each of Patent Documents 1 and 2, and in terms of the photoelectric conversion efficiency of the photoelectric conversion element using the compositions.

[0011] Therefore, the present invention aims to provide a composition in which the dispersion stability of the composition and the photoelectric conversion efficiency of the photoelectric conversion element using the composition are improved.

[0012] Solution for solving the problem

[0013] The above objective is achieved by the present invention as described below. Specifically, the present invention relates to a composition comprising: a pigment as a cyclic conjugated compound in which a plurality of pyrrole rings are linked by conjugated bonds; a dispersant; a resin; and a solvent.

[0014] The dispersant is a calixarene compound represented by formula [A], and

[0015] The mass of the dispersant in the composition is more than 0.20 times the mass of the resin in the composition.

[0016] [Chemical Formula 1]

[0017]

[0018] In formula [A], R 1 ~R 5 Each repeating unit is independent, and each of the "n" repeating units is independent, as follows: R 1 Indicates a hydrogen atom or an alkyl group; R 2 Indicates substituted or unsubstituted alkylene groups; R 3 ~R 5 Each represents a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted -Y-Ar group, a substituted or unsubstituted aromatic hydrocarbon group, or a substituted or unsubstituted heterocyclic group, and R 3 ~R 5 At least one of them represents a substituted or unsubstituted -Y-Ar group, wherein -Y- in the -Y-Ar group represents -CH=N-, -CH=CH- or -N=N-, Ar represents a substituted or unsubstituted aromatic hydrocarbon group or a substituted or unsubstituted heterocyclic group, and "n" represents an integer of 3 or more and 20 or less.

[0019] The effects of the invention

[0020] According to the present invention, the dispersion stability of the composition is improved, and the photoelectric conversion efficiency of the photoelectric conversion element using the composition as a charge transport layer coating liquid is also improved. Attached Figure Description

[0021] [ Figure 1 This is a schematic cross-sectional view of the photoelectric conversion element of the present invention in the thickness direction.

[0022] [ Figure 2 [Perspective view illustrating an example of a moving body incorporating the photoelectric conversion element of the present invention.]

[0023] [ Figure 3 [A perspective view illustrating an example of a building material incorporating the photoelectric conversion element of the present invention.] Detailed Implementation

[0024] The composition of the present invention comprises: a pigment as a cyclic conjugated compound wherein a plurality of pyrrole rings are linked by conjugated bonds; a dispersant; a resin; and a solvent.

[0025] The dispersant is a calixarene compound represented by formula [A], and

[0026] The mass of the dispersant in the composition is more than 0.20 times the mass of the resin in the composition.

[0027] [Chemical Formula 2]

[0028]

[0029] In equation [A], R 1 ~R 5 Each repeating unit is independent, and each of the "n" repeating units is independent, as follows: R 1 Indicates a hydrogen atom or an alkyl group; R 2 Indicates substituted or unsubstituted alkylene groups; R 3 ~R 5 Each represents a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted -Y-Ar group, a substituted or unsubstituted aromatic hydrocarbon group, or a substituted or unsubstituted heterocyclic group, and R 3 ~R 5 At least one of them represents a substituted or unsubstituted -Y-Ar group, wherein -Y- in the -Y-Ar group represents -CH=N-, -CH=CH- or -N=N-, Ar represents a substituted or unsubstituted aromatic hydrocarbon group or a substituted or unsubstituted heterocyclic group, and "n" represents an integer of 3 or more and 20 or less.

[0030] As a result of their research, the inventors of this invention discovered that the dispersion stability of the above-described composition and the photoelectric conversion efficiency of the photoelectric conversion element using the composition as a charge transport layer coating liquid can be improved. In this invention, the specific reasons for the improved dispersion stability of the composition and the photoelectric conversion efficiency of the photoelectric conversion element using the composition as a charge transport layer coating liquid are not yet clear, but the mechanism of improvement is envisioned as follows.

[0031] As used herein, the term "dispersion stability" specifically refers to a pigment particle size of 1.0 × 10⁻⁶ in the dispersed composition. 1 nm or larger and 5.0 × 10 2 The particle size is below nm and this particle size persists for a long period of time (i.e., at least 3 months).

[0032] The particle size of the pigment particles in the composition can be determined using a Zetasizer Nano ZS (manufactured by Malvern Panalytical Ltd.). Particle size can be determined using this device via dynamic light scattering. First, the composition is diluted to prepare a diluent such that the solid-liquid ratio of the particles to be tested is 0.10% by mass (+ / - 0.02% by mass). The diluent is collected in a quartz cell, which is then inserted into the measuring unit. A liquid identical to the solvent used to form the charge transport layer coating is prepared and used as the diluent. For the measurement conditions, the refractive index and viscosity of the dispersion solvent at 20°C are input using Zetasizer software 6.30, and the measurement is performed at 20°C to determine the Z-mean particle size. In the case of mixed solvents, the weight average of the mixed dispersion media is used.

[0033] According to existing technical literature, when the photoelectric conversion layer contains crystals with a perovskite structure, submicron-level irregularities are generated on its surface. It is speculated that high photoelectric conversion efficiency can be obtained by filling the recesses of the irregularities with pigment particles formed from phthalocyanine compounds (which are cyclic compounds in which multiple pyrrole rings are linked by conjugated bonds), thereby stabilizing the interfacial bonding with the electrode.

[0034] However, it has been found that the above is insufficient, and there is still room for improvement in both the dispersion stability of the composition and the photoelectric conversion efficiency of the photoelectric conversion element using the composition as a charge transport layer coating liquid.

[0035] The inventors of this invention speculate that the following composition of the pigment composition contributes to the dispersion stability of the pigment particles in the composition and helps to achieve higher photoelectric conversion efficiency when the composition is used as a coating liquid for a charge transport layer to manufacture a photoelectric conversion element: in addition to the solvent and a cyclic conjugated compound in which a plurality of pyrrole rings are linked by conjugated bonds, a calixarene compound of formula [A] and a resin are added as dispersants; and the mass of the dispersant in the composition is more than 0.20 times the mass of the resin in the composition.

[0036] Regarding dispersion stability, it is enhanced when multiple pyrrole rings in a cyclic compound linked by conjugated bonds, a calixarene compound as shown in formula [A], a resin, and a solvent interact with each other. This is presumably because the hydrophobic portion of the calixarene compound with a cup-shaped structure (R in formula [A])... 3 R 4 and R 5 The hydrophilic side (R of formula [A]) interacts with cyclic compounds in which multiple pyrrole rings are linked by conjugated bonds, while its hydrophilic side (R of formula [A]) interacts with cyclic compounds in which multiple pyrrole rings are linked by conjugated bonds. 1 The pigment particles interact with the resin and solvent. Therefore, it is believed that the dispersion stability of pigment particles is poor when either the dispersant or the resin is absent.

[0037] Furthermore, when the mass of the dispersant in the composition is less than 0.20 times the mass of the resin in the composition, although it is expected that the cyclic compound in which the pyrrole rings are linked by conjugation bonds will preferentially interact with the calixarene compound represented by formula [A], in reality, the resin interacts with the cyclic compound in which the pyrrole rings are linked by conjugation bonds to an excessive degree. As a result, compared with the case where the mass is greater than 0.20 times, uniform dispersion of pigment particles is difficult to achieve, agglomeration increases, and dispersion stability deteriorates.

[0038] Regarding the efficiency of forming photoelectric conversion elements, it is speculated that when the coating solution is applied to the perovskite, the proportion of the perovskite that cannot be filled by cyclic compounds in which multiple pyrrole rings are bonded by conjugated bonds increases, the interfacial bonding becomes more unstable, and as a result, the photoelectric conversion efficiency decreases.

[0039] Based on the above mechanism, it is believed that when the components interact synergistically, the dispersion stability of the pigment particle composition is improved, and the perovskite can be densely filled, thus stabilizing the interfacial bonding with the electrode and thereby improving the photoelectric conversion efficiency.

[0040] In the compositions of the present invention, the solvent is one that does not damage the perovskite crystals. Specifically, as a method for selecting a solvent that does not damage the perovskite crystals, after coating the perovskite film with the solvent and then allowing it to stand for 1 hour, if the concentration and color of the film do not change, it is confirmed that the perovskite crystals have not been damaged.

[0041] Furthermore, the solvent needs to dry rapidly after being coated onto the perovskite; therefore, a vapor pressure (at 20°C) of 0.06 kPa or higher is preferred. Rapid drying of the solvent reduces defects such as particle aggregation and inadequate coverage of the perovskite. When the above conditions are met in a mixture of two or more solvents, these solvents can be used as a mixed solvent. The vapor pressure in the case of two or more solvents is determined as a value obtained by adding the product of the vapor pressure of each solvent and its weight ratio in the mixed solvent. There are no specific examples of solvents, as long as the following two conditions are met: they do not damage the perovskite crystals; and the vapor pressure is within the above range, including hydrocarbon-based, ester-based, ketone-based, ether-based, aromatic compound-based, and alcohol-based solvents. From the viewpoint of satisfying the above conditions and dispersion stability, alcohol-based solvents are preferred as the main solvent.

[0042] In the compositions of the present invention, a cyclic compound (which serves as a pigment) in which multiple pyrrole rings are linked by conjugated bonds is dispersed in a coating liquid and exists in particulate form. When the cyclic compound forms a film in particulate form, it maintains high crystallinity and exhibits inherently high charge transport capabilities.

[0043] Specific examples of cyclic compounds in this invention in which multiple pyrrole rings are linked by conjugated bonds include: porphyrin derivatives, such as tetraphenylporphyrin, diphenylporphyrin, tetrapyridylporphyrin, copper porphyrin, copper tetraphenylporphyrin, copper octaethylporphyrin, cobalt tetraphenylporphyrin, octaethylporphyrin, chlorophenylporphyrin, methoxyphenylporphyrin, methylphenylporphyrin, zinc porphyrin, magnesium porphyrin, octabutoxyporphyrin, chloromanganese porphyrin, metal-free tetrazaporphyrin, copper tetrazaporphyrin, zinc tetrazaporphyrin, nickel tetrazaporphyrin, and titanium tetrazaporphyrin. Phthalocyanines, tetraphenyltetraazaporphyrins, and octaphenyltetraazaporphyrins; phthalocyanine derivatives, such as hydroxygallium phthalocyanine, chlorogallium phthalocyanine, copper phthalocyanine, zinc phthalocyanine, phthalocyanine, cobalt phthalocyanine, titanium phthalocyanine, dichlorotin phthalocyanine, magnesium phthalocyanine, tin phthalocyanine, lead phthalocyanine, iron phthalocyanine, vanadium phthalocyanine, aluminum chlorophthalocyanine, nickel phthalocyanine, silicon phthalocyanine dichloride, indium chlorophthalocyanine, manganese phthalocyanine, ferric chlorophthalocyanine, and platinum phthalocyanine; and naphthalene phthalocyanine derivatives, such as naphthalene phthalocyanine, magnesium naphthalene phthalocyanine, copper naphthalene phthalocyanine, cobalt naphthalene phthalocyanine, vanadium chloronaphthalocyanine, tin naphthalene phthalocyanine, and dichlorotin naphthalene phthalocyanine.

[0044] In this invention, porphyrin compounds and phthalocyanine compounds are preferred, and phthalocyanine compounds are more preferred from the viewpoint of expanding the π-electron cloud, which serves as the starting point for interaction with perovskite. The central element of the phthalocyanine compound is preferably metal-free or at least one of gallium, aluminum, titanium, iron, or silicon. Phthalocyanine, gallium phthalocyanine, titanium phthalocyanine, aluminum phthalocyanine, iron phthalocyanine, and silicon phthalocyanine are particularly preferred as phthalocyanine compounds. Among these, gallium phthalocyanine is more preferred, and hydroxygallium phthalocyanine compounds are particularly preferred. Furthermore, from the viewpoint of electronic interactions, when measuring the X-ray diffraction spectrum of the film of the composition, the ratio of the peak intensity in the range of Bragg angle 2θ being 7.6° or more and 8.6° or less to the total peak intensity in the range of 0.0° or more and 30.0° or less is preferably 0.02 or more. In this invention, for example, the chemical structure of a cyclic conjugated compound in which multiple pyrrole rings are linked by conjugated bonds can be confirmed by, for example, nuclear magnetic resonance (NMR).

[0045] In the compositions of the present invention, the dispersant is a calixarene compound represented by the following formula [A]:

[0046] [Chemical Formula 3]

[0047]

[0048] In formula [A], R 1 ~R 5 Each repeating unit is independent, and each of the "n" repeating units is independent, as follows: R 1 Indicates a hydrogen atom or an alkyl group; R 2 Indicates substituted or unsubstituted alkylene groups; R 3 ~R 5 Each represents a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted -Y-Ar group, a substituted or unsubstituted aromatic hydrocarbon group, or a substituted or unsubstituted heterocyclic group, and R 3 ~R 5 At least one of them represents a substituted or unsubstituted -Y-Ar group, wherein -Y- in the -Y-Ar group represents -CH=N-, -CH=CH- or -N=N-, Ar represents a substituted or unsubstituted aromatic hydrocarbon group or a substituted or unsubstituted heterocyclic group, and "n" represents an integer of 3 or more and 20 or less.

[0049] R 1 ~R 5 Examples of alkyl groups shown include methyl, ethyl, propyl, and butyl.

[0050] R 3 ~R 5 Examples of aromatic hydrocarbon groups shown include benzene, naphthalene, fluorene, phenanthrene, anthracene, fluoranthene, and pyrene.

[0051] In addition, R 3 ~R 5 Examples of heterocyclic groups shown include furan, thiophene, pyridine, indole, benzothiazole, carbazole, benzocarbazole, acridinone, dibenzothiazole, benzoxazole, benzotriazole, oxiazole, thiazole, phenazine, borazine, and benzoborazine.

[0052] In addition, R 2 ~R 5 Examples of substituents that may be present in the respective alkyl, phenyl azo, aromatic hydrocarbon, or heterocyclic groups include: alkyl, such as methyl, ethyl, propyl, and butyl; alkoxy, such as methoxy and ethoxy; dialkylamino, such as dimethylamino and diethylamino; alkoxycarbonyl, such as methoxycarbonyl and ethoxycarbonyl; halogen atom, such as fluorine, chlorine, and bromine; hydroxyl; nitro; cyano; and halomethyl.

[0053] In the aromatic ring compound with a calixarene structure shown by formula [A], from the viewpoint of molecular size, in order to improve dispersion stability, "n" preferably means 4 or more and 8 or less, and its molecular weight is preferably 10,000 or less.

[0054] Furthermore, in this invention, R 1 Preferably, each of the "n" repeating units independently represents a hydrogen atom, methyl, ethyl, or propyl group. Furthermore, R 2 Preferably, each of the "n" repeating units independently represents methylene, ethylene, or trimethylene. R is preferred. 3 and R 5 Each represents a hydrogen atom, and R 4 Each of the “n” repeating units independently represents either nitrophenylazo or dinitrophenylazo.

[0055] Specific examples of calixarene compounds that are particularly preferred in this invention are given below. In this invention, the composition preferably contains at least one of the following groups as a dispersant: a compound represented by formula [C-1], a compound represented by formula [C-2], a compound represented by formula [C-3], and a compound represented by formula [C-4], and more preferably contains all four compounds (mixed product).

[0056] [Chemical Formula 4]

[0057]

[0058] [Chemical Formula 5]

[0059]

[0060] [Chemical Formula 6]

[0061]

[0062] [Chemical Formula 7]

[0063]

[0064] In this invention, the chemical structure of aromatic ring compounds with calixarene structures, as shown in formula [A], can be confirmed by, for example, nuclear magnetic resonance (NMR).

[0065] From the viewpoint of the dispersion stability of pigment particles, the mass of the dispersant in the composition of the present invention is preferably 0.01 times or more and 0.50 times or less relative to the mass of the pigment particles in the composition (which are cyclic compounds in which a plurality of pyrrole rings are linked by conjugated bonds).

[0066] In the compositions of the present invention, specific examples of resins include polyacetal resins, acrylic resins, polyarylate resins, polycarbonate resins, polyvinyl acetate resins, polyester resins, polyamide resins, polyurethane resins, and polystyrene resins.

[0067] The resin is preferably a resin with Lewis basic functional groups. When the Lewis basic functional groups exert electronic effects on the pigment particles (which are cyclic compounds in which multiple pyrrole rings are linked by conjugated bonds) and the dispersant (which are calixarene compounds), the interaction between the pigment particles and the resin increases, the resin can easily intervene between the particles, and the steric stabilization effect of the resin can be easily obtained.

[0068] Specific examples of Lewis basic functional groups include hydroxyl, halogen, sulfonyl, amino, carbonyl, ester, ether, carboxyl, aldehyde, methoxy, amide, thioether, cyano, thiophene, pyridyl, furan, pyrazole, imidazole, oxazole, and thiazole. From the viewpoint of electronic interactions, hydroxyl, carbonyl, ether, ester, pyridyl, and thiophene groups are preferred. In particular, from the viewpoint of ease of interaction, the resin more preferably has at least two of these functional groups. A resin may have different functional groups, or two resins with different functional groups may be mixed. The Lewis basic functional group is preferably contained in the repeating structure of the resin.

[0069] Specific examples of resins with Lewis basic functional groups preferably used in this invention include: polyvinyl butyral, poly(4-vinylpyridine), poly(vinyl chloride), poly(vinylidene fluoride), polyacrylonitrile, poly(vinylidene fluoride-co-hexafluoropropylene), poly(acrylonitrile-co-butadiene), poly(styrene-co-acrylonitrile), polychloroprene, poly(4-chlorostyrene), polymethyl methacrylate, polyvinyl acetate, polyethyleneimine, polyvinyl alcohol, polyacrylic acid, sodium poly(4-styrene sulfonate), poly(allylamine hydrochloride), sodium polyacrylate, poly(4-styrene sulfonic acid), poly(N-isopropylacrylamide), poly(2-ethyl-2-oxazoline), poly(ethylene-alt-maleic anhydride), poly(2-acrylamido-2-methyl-1-propanesulfonic acid), potassium poly(vinyl sulfate), sodium polyaniline sulfonate, poly(2-(dimethylamino)ethyl methacrylate) methyl chloride quaternary ammonium salt, poly( Methyl vinyl ether), poly(2-propyl acrylate), polyvinylpyrrolidone, polypropylene glycol, poly(propylene carbonate), polyvinyl acetate, poly(tetrahydrofuran), nylon-6, poly(ethylene-co-vinyl acetate), poly(propylene glycol) bis(2-aminopropyl ether), poly(bisphenol A carbonate), poly(1,4-butanediol adipate), poly(4-vinylphenol), poly(propylene glycol) monobutyl ether, poly(glycidyl methacrylate), poly( The resins include butyl acrylate, poly(ethylene glycol succinate), poly(propylene glycol) methacrylate, nylon 11, nylon 12, poly(2-ethylhexyl acrylate), poly(propylene glycol) bis(2-aminopropyl ether), polyetherimide, poly(vinyl alcohol formaldehyde), poly(vinyl methyl ketone), poly(3-hexylthiophene-2,5-diyl), polyaniline, and a complex of poly(3,4-ethylenedioxythiophene) and polystyrene sulfonic acid (PEDOT:PSS). From the viewpoint of electronic interactions, polyvinyl butyral, polymethyl methacrylate, poly(3-hexylthiophene-2,5-diyl), polyvinyl acetate, polyvinyl alcohol, polyacrylic acid, poly(2-propyl acrylic acid), poly(butyl acrylate), and poly(4-vinylpyridine) are more preferred, and polyvinyl acetal resin and polyvinyl butyral resin are particularly preferred. These resins readily interact with pigment particles (which are cyclic compounds in which multiple pyrrole rings are linked by conjugated bonds).

[0070] More preferably, the glass transition temperature (Tg) of the resin is below 95°C. When the glass transition temperature is within this range, it is easier for the resin to come into close contact with the pigment particles, which are charge-transporting particles, and the improvement in coverage achieved through interaction becomes more effective. The glass transition temperature can be determined using a differential scanning calorimeter (DSC).

[0071] From the viewpoint of dispersibility and film-forming properties, the molecular weight of the resin, expressed as a weight-average molecular weight, is preferably in the range of 1,000 to 1,000,000.

[0072] In the compositions of the present invention, the mass of the pigment particles (which are cyclic compounds in which multiple pyrrole rings are linked by conjugated bonds) is preferably 5 to 20 times the mass of the resin in the composition, because the resin readily interacts with the pigment particles and the coverage is easily improved. When the mass of the pigment particles is greater than 20 times, the improvement in coverage achieved through the interaction with the resin is often insufficient. When the mass of the pigment particles is less than 5 times, charge transfer from the photoelectric conversion layer to the particles becomes insufficient, thus making it difficult to improve the photoelectric conversion efficiency.

[0073] The dispersion method of the composition of the present invention includes, for example, using a coating shaker, a sand mill, a ball mill, or a liquid impact type high-speed disperser. In the sand mill, dispersion is achieved by the rotation of a rotating disc within the mill and by the shear force of a medium such as glass beads serving as the grinding medium. Dispersion stability can be varied by dispersion conditions such as dispersion time, bead quantity, disc rotation speed, and the timing of material addition.

[0074] In the preparation of the compositions of the present invention, particularly regarding the timing of resin addition during the manufacturing process, it is necessary to first disperse the pigment, dispersant, and solvent to a certain extent to provide a dispersion (pre-dispersion), and then add the resin later to this dispersion for further dispersion, rather than adding the resin together with the pigment, dispersant, and solvent from the beginning of dispersion. This improves the dispersion stability of the pigment.

[0075] When dispersion stability is improved by, for example, designing the manufacturing method described above, the difference in dispersion stability that cannot be fully determined by the particle size measured using Zetasizer Nano ZS (manufactured by Malvern Panalytical Ltd.) due to factors such as aggregation can be confirmed as needed by imaging methods using scanning electron microscopy (SEM) images or by measuring the specific surface area coefficient using pulsed NMR.

[0076] Furthermore, the determination of the X-ray diffraction spectrum of the composition and the content of cyclic compounds, such as those in which multiple pyrrole rings are linked by conjugated bonds, are described. The analysis of the content of compounds and the X-ray diffraction determination are performed by exposing the surface of the film of the composition by using a dried film of the composition, or by removing the top layer of the charge transport layer of the photoelectric conversion element, which uses the composition as a charge transport layer coating liquid, with an organic solvent such as chloroform.

[0077] [Analysis of compound amount]

[0078] Wipe the surface of the film of the composition with a cotton swab soaked in solvent, dissolve it in deuterated sulfuric acid, and then proceed with... 1 ¹H-NMR determination (equipment: AVANCE III-500, manufactured by Bruker). In addition, the wiped components were subjected to GPC, MALDI-TOF-MS, IR, gas chromatography, and elemental analysis such as XPS or EDX. These quality and structural analyses were performed to determine the presence of compounds and their significant proportions in the resin or dispersant.

[0079] In addition, after cutting the photoelectric conversion element and fixing the sample on the tilted sample stage, the thickness of the film was determined using a cross-sectional SEM (equipment: SmartSEM, manufactured by Carl Zeiss Co., Ltd.).

[0080] MALDI-TOF-MS analysis

[0081] The analysis was performed under the following conditions, and the molecular weight was determined from the obtained peak values.

[0082] Measurement instrument used: Matrix-assisted laser desorption / ionization time-of-flight mass spectrometer (MALDI-TOF MS) Ultraflex, manufactured by Bruker Daltonics Co., Ltd.

[0083] Accelerating voltage: 20kV

[0084] Mode: Reflector

[0085] Molecular weight standard: Fullerene C60

[0086] X-ray diffraction measurement

[0087] The X-ray diffraction spectrum of the film of the composition was determined, and the ratio of the intensity of the peak in the range of Bragg angle 2θ being 7.6° or higher and 8.6° or lower to the total peak intensity in the range of 0.0° or higher and 30.0° or lower was determined.

[0088] Measuring instrument used: RINT-TTRII X-ray diffractometer (manufactured by Rigaku Corporation)

[0089] X-ray tube: Cu

[0090] X-ray wavelength: Kα1

[0091] Tube voltage: 50kV

[0092] Tube current: 300mA

[0093] Scanning method: 2θ-θ scan

[0094] Scanning speed: 0.4° / minute

[0095] Sampling interval: 0.005°

[0096] Initial angle 2θ: 3.0°

[0097] Termination angle 2θ: 30.0°

[0098] Goniometer: Rotor-type horizontal goniometer (TTR-2)

[0099] Filter: None

[0100] Detector: Blink Counter

[0101] Incident monochromator: using

[0102] Slit: Variable slit (parallel beam method)

[0103] Counter monochromator: Not used

[0104] Diverging Slit: Open

[0105] Longitudinal diverging slit: 10.00mm

[0106] Scattering slit: Open

[0107] Receive slit: Open

[0108] The present invention will be described in detail below by way of preferred embodiments. The present invention is not limited to the following embodiments, and appropriate changes and modifications to the following embodiments based on ordinary knowledge of those skilled in the art, without departing from the spirit of the invention, are also included within the scope of the present invention.

[0109] As used herein, the term "layer" refers not only to a layer with clearly defined boundaries or a flat, thin-film shape, but also to a layer with a concentration gradient in which the concentration of elements gradually changes, or a layer that can form a complex, interwoven structure with other layers. Elemental analysis of layers can be performed, for example, by TOF-SIMS / FE-TEM / EDS line analysis of a cross-section of a photoelectric conversion element to determine the elemental distribution of specific elements. Analysis of individual layers can be performed by peeling off and removing the layers from the completed photoelectric conversion element to expose the layer to be analyzed. Furthermore, analysis of compounds in the charge transport layer coating solution can be performed by... 1 Mass and structural analysis is performed using elemental analysis methods such as H-NMR, GPC, MALDI-TOF-MS, IR, gas chromatography, liquid chromatography, or XPS or EDX.

[0110] Figure 1This is a schematic cross-sectional view illustrating the configuration of one embodiment of a photoelectric conversion element using the composition of the present invention as a charge transport layer coating liquid. The photoelectric conversion element 1 includes a substrate 2 and a second electrode 3, an electron transport layer 4, a photoelectric conversion layer 5, a charge transport layer 6, and a first electrode 7 disposed thereon. One of the first electrode 7 and the second electrode 3 is a positive electrode, and the other is a negative electrode. Current can be extracted by connecting the first electrode 7 and the second electrode 3 to an external circuit.

[0111] The photoelectric conversion layer 5 is excited by light entering the layer through the substrate 2, the second electrode 3, and the electron transport layer 4, or the first electrode 7 and the charge transport layer 6, to generate electrons or holes. That is, the photoelectric conversion layer 5 generates a current between the first electrode 7 and the second electrode 3. The electron transport layer 4 is disposed between the photoelectric conversion layer 5 and the two electrodes (the second electrode 3 and the first electrode 7), and in some cases, it may not be formed. A configuration in which multiple electron transport layers 4 and photoelectric conversion layers 5 are stacked can be adopted. This configuration can also be called a "tandem structure". The components are described below.

[0112] [Photoelectric conversion element]

[0113] The photoelectric conversion element of the present invention is characterized by comprising: a first electrode; a second electrode; and a photoelectric conversion layer disposed between the first electrode and the second electrode, the photoelectric conversion layer containing a crystal having a perovskite structure; and a charge transport layer between the photoelectric conversion layer and the first electrode. Furthermore, to improve photoelectric conversion efficiency, a series-connected type in which the photoelectric conversion elements are stacked can also be used. There is no limitation on the type of photoelectric conversion element to be stacked; for example, in addition to perovskite solar cells using perovskite crystals in the photoelectric conversion layer, silicon solar cells or CIGS solar cells can also be used.

[0114] The methods for forming the layers of the photoelectric conversion element of the present invention include, for example, coating methods and vapor deposition methods. Examples of coating methods include dip coating, spin coating, spray coating, inkjet coating, meniscus coating, screen coating, roll coating, die coating, doctor blade coating, curtain coating, and wire rod coating. A coating method includes preparing a coating liquid for each layer described below, applying the liquid in the desired layer sequence, and drying the liquid. As such film-forming methods, the desired method is selected according to each layer.

[0115] The following section describes each layer.

[0116] [Substrate]

[0117] The photoelectric conversion element 1 of the present invention may include a substrate 2, examples of which include a transparent glass substrate, a ceramic substrate, and a transparent plastic substrate made of soda-lime glass or alkali-free glass. When light is taken in from the side of the first electrode 7, an opaque material may be used as the substrate 2, and when light is taken in from the side of the second electrode 3, the substrate 2 is formed of a transparent material.

[0118] [electrode]

[0119] There are no particular limitations on the materials used for the first electrode 7 or the second electrode 3; materials known to date can be used. Examples include: metals such as gold, silver, titanium, and copper; sodium; sodium-potassium alloys; lithium; magnesium; carbon; aluminum; magnesium-silver mixtures; magnesium-indium mixtures; aluminum-lithium alloys; Al / Al2O3 mixtures; and Al / LiF mixtures. Examples of transparent electrode materials include: conductive transparent materials such as CuI, indium tin oxide (ITO), SnO2, zinc aluminum oxide (AZO), indium zinc oxide (IZO), zinc gallium oxide (GZO), fluorine-doped tin oxide (FTO), and antimony-doped tin oxide (ATO); and conductive transparent polymers. These materials can be used alone or in combination. At least one of the electrodes in the first electrode 7 or the second electrode 3 on the light incident side is a transparent electrode, and the other can be a transparent electrode or may also act as a reflective layer formed of a light-reflective material, or may be a transparent electrode contained in a reflective layer on the side opposite to the light incident side. When the first electrode 7 is on the light incident side, the second electrode 3 and the substrate 2 can be a transparent electrode and a reflective layer, respectively. The electrode can be a patterned electrode.

[0120] [Photoelectric conversion layer]

[0121] The photoelectric conversion layer 5 comprises a crystal with a perovskite structure. The crystal with a perovskite structure used in this invention is preferably represented by the following general formula [1].

[0122] ABX3 [1]

[0123] In the general formula [1], A represents a monovalent cation of an organic molecule or metal atom, B represents a divalent metal cation, and X represents a monovalent halide anion.

[0124] In general formula [1], A preferably represents C in the case of organic molecules, for example. p N m H n ("p", "m", and "n" each represent a positive integer). Specific examples include methylammonium and formamidon.

[0125] Furthermore, there are no particular restrictions on the metal atoms, with lithium, cesium, sodium, potassium, and rubidium being preferred. These organic molecules or metal atoms can be used alone or in combination.

[0126] When the contained cation A is too large to fit within a crystal with a 3D perovskite structure, it forms a crystal with a 2D perovskite structure, a crystal with a 2.5D perovskite structure possessing properties of both 2D and 3D perovskite structures, a bilayer crystal with both 3D and 2D perovskite structures, or a crystal with a mixed 3D / 2D perovskite structure. Any of these structures functions as a photoelectric conversion layer. A bilayer crystal with both 3D and 2D perovskite structures refers to a crystal in which 3D and 2D perovskite structures are stacked as independent and separate layers. A crystal with a mixed 3D / 2D perovskite structure refers to a crystal with the following structure: a mixture of regions or domains of 2D or 2.5D layered and 3D perovskite structures.

[0127] Preferably, crystals having a 2D perovskite or 2.5D perovskite structure are represented by the following general formulas [2] to [4].

[0128] R′2A n-1 B n X 3n+1 [2]

[0129] R″A n-1 B n X 3n+1 [3]

[0130] R″′A n B n X 3n+1 [4]

[0131] General formulas [2], [3] and [4] form Ruddlesden-Popper (RP), Dion-Jacobson (DJ) and interlayer alternating cation (ACI) perovskite structures, respectively.

[0132] In general formulas [2] to [4], R′, R″, and R″′ preferably represent C in the case of organic molecules, for example. p N m H n(“p”, “m”, and “n” each represent a positive integer). Furthermore, A may or may not have substituents. Specifically, ethylammonium, propylammonium, n-butylammonium, n-hexylammonium, n-octylammonium, 1,6-hexammonium diammonium, isobutylammonium, 3-(nonafluoro-tert-butoxy)propylamine, 1,3-propanediammonium, 1,5-pentamethylenediamine, octyldiammonium, 2,2-(ethylenedioxy)bis(ethylammonium), 5-aminovaleric acid, 4-tert-butylammonium, N,N′-dimethylethylene-1,2-diammonium, 2,2,3,3,3-pentafluoropropylammonium, guanidinium, propylammonium, propargylamine, alkylammonium, cyclohexylmethylammonium, 4-(aminomethyl)piperidinium, piperidinium, pyrrolidineonium, cyclohexylammonium, 4-fluoro Phenethylammonium, 4-fluorophenylethylammonium, trifluoromethylbenzylammonium, pentafluorobenzylammonium, pentafluorophenylethylammonium, 4-methoxyphenylethylammonium, imidazolium, pyridinium, 3-thiophenemethylammonium, 2-thiopheneethylammonium, 2-thiopheneformamidinium, 2-thiophenemethylammonium, 1-naphthylmethylammonium, 2-naphthylmethylammonium, phenethylammonium, phenylammonium, benzylammonium, 2,5-thiophenedimethylammonium, phenylpropylammonium, 1,4-phenylenediamine, 3-phenyl-2-propen-1-ammonium, phenylbutylammonium, 4-tert-butylbenzylammonium, 3-(aminomethyl)piperidinium, and 4-(aminomethyl)piperidinium are preferred.

[0133] In each of the general formulas [1] to [4], B represents a metal atom, examples of which include lead, tin, bismuth, zinc, titanium, antimony, nickel, iron, cobalt, silver, copper, gallium, germanium, magnesium, calcium, indium, aluminum, manganese, chromium, molybdenum, and europium. Among these, lead, tin, and bismuth are preferred from the viewpoint of electron orbital overlap. These metal atoms can be used individually or in combination.

[0134] In each of the general formulas [1] to [4], X represents a halogen atom, examples of which include chlorine, bromine, and iodine. These halogen atoms can be used alone or in combination. Halogen atoms are preferred because when the structure contains halogen atoms, the crystals with the perovskite structure described above become readily soluble in organic solvents, thereby enabling their application in inexpensive printing methods, etc. Iodine is even more preferred because the energy band gap of crystals with the perovskite structure is narrowed.

[0135] Specifically, MAPbI3, FAPbCl3, FAPbI3, and MAPbI are 3D perovskites, 2D perovskites, and mixed 3D / 2D perovskites. x Br 3-x MAPbI x Cl 3-x Cs 0.05 (MA 0.17 FA 0.83 ) 0.95 Pb(I 0.83 Br 0.17 )3、{Csx1 (FA x2 MA 1-x2 ) 1-x1} x3 Pb(I x4 Br 1-x4 ) x5 、Cs 0.05 FA 0.88 MA 0.07 PbI 2.56 Br 0.44 、(FAPbI3) 0.95 (MAPbBr3) 0.05 、(FAPbI3) 0.85 (MAPbBr3) 0.15 、CsPbI3、CsPbBr3、Cs x (MA) 1-x PbI3、Cs x (FA) 1-x PbI3、MA x (FA) 1-x PbI3、MA 0.17 FA 0.83 Pb(I 0.83 Br 0.17 )3、Cs 0.15 FA 0.85 PbI 2.55 Br 0.45 、Cs 0.05 FA 0.88 MA 0.07 PbI 2.56 Br 0.44 、Cs 0.15 FA 0.85 PbI 2.55 Br 0.45 、(AND)2(MA)2Pb3I 10 、(PTA)2(MA)4Pb5I 16 、(AND)2(MA)4Pb5I 16 、(ThMA)2(MA)2Pb3I 10 、(3BBA)2(MA)2Pb3I 10 、(ThMA)2(FA)4Pb5I 16 、(pF-AND)2(FA 0.3 MA 0.7 )4Pb5I 16 、(PDMA)FA2Pb3I 10 、(3AMPY)(MA)3Pb4I 13 、(PDMA)MA5Pb6I 19(PDMA)MA3Pb4I 13 (TTDMA)MA3Pb4I 13 (TTDMA)MA4Pb5I 16 、(BA 0.9 PEA 0.1 )2MA4Pb5I 16 、(BA 0.9 PEA 0.1 )2MA3Pb4I 13 (4FPEA)2MA3Pb4I 13 (4FPEA)2MA4Pb5I 16 (BA)2MA2Pb3I 10 (BA)2MA3Pb4I 13 (TEA)2MA2Pb3I 10 (BA)2MA4Pb5I 16 and (BA)2MA3Pb4I 13 This is preferred. The number of A, B, or X positions in each general formula can be adjusted to be too few or too many according to the purpose, and the combination of x1 to x5 can be changed according to the purpose. Examples of the combinations of x1 to x5 are shown in Table 1. Particularly preferred ranges are: 0.03≤x1≤0.10, 0.80≤x2≤0.96, 0.95≤x3≤1.05, 0.80≤x4≤0.96, and 2.95≤x5≤3.05. MACl can be incorporated as a material for forming perovskite crystals.

[0136] [Table 1]

[0137]

[0138] In the specific examples above, "MA" represents methylammonium, "FA" represents formamidinium, "PEA" represents phenylethylammonium, "PTA" represents phenyltriethylammonium, "ThMA" represents 2-thiophenemethylammonium, "3BBA" represents 3-bromobenzylammonium, "3AMPY" represents 3-(aminomethyl)pyridine, "PDMA" represents 1,4-phenylenediamine, "TTDMA" represents thieno[3,2-b]thiophene-2,5-dimethylammonium, "4FPEA" represents 4-fluorophenylethylammonium, "BA" represents butylammonium, and "TEA" represents 2-thiopheneethylammonium.

[0139] The aforementioned perovskite-structured crystals preferably have a cubic crystal structure in which metal atoms B, organic molecules A, and halogen atoms X are respectively positioned at the body center, vertices, and face centers. While the details are unclear, it is speculated that the orientation of the octahedrons within the crystal lattice can be easily altered when such a structure exists, thus increasing the electron mobility in the perovskite-structured crystal and improving the photoelectric conversion efficiency of the photoelectric conversion element.

[0140] The organic-inorganic perovskite compound used in this invention is preferably a crystalline semiconductor. The term "crystalline semiconductor" refers to a semiconductor capable of measuring the intensity distribution of X-ray scattering to detect scattering peaks. When the organic-inorganic perovskite compound is a crystalline semiconductor, the electron mobility in the compound increases, and the photoelectric conversion efficiency of the photoelectric conversion element is improved.

[0141] The thickness of the photoelectric conversion layer according to the present invention is preferably 5 nm or more and 2,000 nm or less. When the thickness is 5 nm or more, sufficient light absorption is possible, and when the thickness is 2,000 nm or less, the generated charge can be transported to each electrode. More preferably, the lower limit is 50 nm or more, more preferably, the upper limit is 1,200 nm, even more preferably, the lower limit is 100 nm, and even more preferably, the upper limit is 1,000 nm.

[0142] [charge transport layer]

[0143] In the photoelectric conversion element of the present invention, a charge transport layer is disposed between the photoelectric conversion layer and the first electrode, and the charge transport layer contains a charge transporting substance and a resin, and is disposed on the surface of the photoelectric conversion layer.

[0144] The charge transport layer can be formed by preparing a coating liquid for the charge transport layer as described above, forming a coating film of the coating liquid on the photoelectric conversion layer, and drying the coating film. Methods for forming the coating film include, for example, dip coating, spin coating, spray coating, inkjet coating, meniscus coating, screen coating, roller coating, die coating, doctor blade coating, curtain coating, or wire rod coating.

[0145] The photoelectric conversion element of the present invention may include a second charge transport layer between the first electrode and the charge transport layer. When the photoelectric conversion element includes a second charge transport layer, it can facilitate the transfer of charge carriers to the electrode.

[0146] The thickness of the charge transport layer is preferably 1 nm or more and 1,000 nm or less, more preferably 5 nm or more and 500 nm or less, and particularly preferably 10 nm or more and 200 nm or less.

[0147] [Second charge transport layer]

[0148] In this invention, from the viewpoint of compatibility of the charge transport layer 6 film, the photoelectric conversion element 1 may further include a second charge transport layer between the charge transport layer 6 and the first electrode 7.

[0149] There are no particular limitations on the material of the second charge transport layer, and examples include spirofluorene compounds, triphenylamine compounds, phenylene compounds, pyrene compounds, phthalocyanine compounds, carbazole compounds, fluorene compounds, phenylcyclohexane compounds, benzidine compounds, phenoxazine compounds, phenylenediamine compounds, and thiocyanate compounds. From the viewpoint of membrane interface compatibility, the compounds preferably have aromatic rings, and Spiro-OMeTAD, PTAA, or phthalocyanine compounds are particularly preferred.

[0150] [Electron transport layer]

[0151] In the photoelectric conversion element of the present invention, such as Figure 1 As shown, an electron transport layer 4 can be disposed between the second electrode 3 and the photoelectric conversion layer 5.

[0152] There are no particular limitations on the materials used for electron transport layer 4, and examples 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, and surfactants. Specific examples include cyano-containing polyphenylene vinylidenes, boron-containing polymers, copper bath compounds, phenanthroline, aluminum hydroxyquinoline, oxadiazole compounds, benzimidazole compounds, naphthalenetetracarboxylic acid compounds, perylene derivatives, phosphine oxide compounds, phosphine sulfide compounds, fluorine-containing phthalocyanines, titanium dioxide, zinc oxide, indium oxide, tin oxide, gallium oxide, tin sulfide, indium sulfide, and zinc sulfide. In particular, tin oxide can be obtained by reacting tin(II) chloride, tin(IV) chloride, tin(II) chloride dihydrate, or tin(IV) chloride pentahydrate.

[0153] The preferred lower limit for the thickness of the electron transport layer 4 is 1 nm, and the preferred upper limit is 2,000 nm. When the thickness is above 1 nm, holes can be sufficiently blocked, and when the thickness is below 2,000 nm, the electron transport layer 4 is unlikely to act as a resistor during electron transport, thus improving the photoelectric conversion efficiency. A more preferred lower limit for the thickness is 3 nm, a more preferred upper limit is 1,000 nm, a still more preferred lower limit is 5 nm, and a still more preferred upper limit is 500 nm.

[0154] <Application Example>

[0155] Applications of this invention relate to photoelectric conversion devices, mobile bodies, and building materials.

[0156] Photoelectric conversion equipment

[0157] The photoelectric conversion device of the present invention includes the aforementioned photoelectric conversion element. A photoelectric conversion device can be formed by using multiple photoelectric conversion elements of the present invention. When multiple photoelectric conversion elements are connected, such a photoelectric conversion device can also be called a "photoelectric conversion battery" or a "photoelectric conversion module". Photoelectric conversion elements with different absorption wavelengths can be stacked as photoelectric conversion elements to improve the output voltage. Furthermore, the photoelectric conversion device includes the photoelectric conversion element of the present invention and an inverter. The inverter can be a converter that converts DC voltage to AC voltage. The photoelectric conversion device can include a power storage unit connected to the photoelectric conversion element. There are no limitations on the power storage unit, as long as the power storage unit is capable of storing electricity. Examples include secondary batteries using lithium ions, all-solid-state batteries, and double-layer capacitors.

[0158] [Moving Object]

[0159] The mobile body of the present invention includes the above-described photoelectric conversion element. Figure 2 This is a schematic perspective view of a mobile body including a photoelectric conversion element according to an embodiment of the present invention. The mobile body 30 includes the photoelectric conversion element 31 of the present invention and a body 32 housing the photoelectric conversion element 31. The photoelectric conversion element 31 is disposed at a position on the body 32 capable of receiving ambient light. When the mobile body 30 is a vehicle, the photoelectric conversion element 31 may also be disposed on the roof. The electrical energy obtained through the photoelectric conversion element 31 can serve as the power source for the mobile body 30 or any other electrical device. The electrical energy generated by the power source of the mobile body 30 can be used to power the photoelectric conversion element 31. When the mobile body 30 is a vehicle, the frictional energy generated by braking can be converted into electrical energy for the control of the photoelectric conversion element 31.

[0160] The mobile body 30 can be, for example, a car, a ship, an airplane, or a drone. There are no particular restrictions on the composition of the fuselage 32 of the mobile body 30, but it is preferably formed of a material with high strength.

[0161] [Building Materials]

[0162] The building material of the present invention includes the above-mentioned photoelectric conversion element. Figure 3 This is a perspective view schematically illustrating a building material comprising a photoelectric conversion element according to an embodiment of the present invention. Building material 40 may be the roof of a building. Building material 40 of this embodiment comprises the photoelectric conversion element 41 of the present invention, a protective member 42 for protecting the photoelectric conversion element 41, a heat dissipation member 43, and exterior finishes 44a and 44b.

[0163] The building material 40 of the present invention may include a heat dissipation member 43 with a thermal conductivity higher than that of the photoelectric conversion element 41. When the building material 40 is used in the roof, etc., sunlight can cause the temperature of the photoelectric conversion element 41 to rise, which may reduce the photoelectric conversion efficiency. By using the heat dissipation member 43, the reduction in photoelectric conversion efficiency can be suppressed. Examples of heat dissipation members 43 include metals, alloys, liquid metals, and liquid resins.

[0164] Furthermore, the building material 40 of the present invention may include exterior finishes 44a and 44b. Exterior finishes 44a and 44b may be different colors or the same color. Exterior finishes 44a and 44b may be composed of the same components or different components. Paint or a transparent substrate may be used for each exterior finish. Exterior finishes with low light absorption and high heat shielding properties are preferred.

[0165] Example

[0166] The invention is described in more detail below with reference to embodiments and comparative examples. The invention is not limited to the following embodiments without departing from its spirit. In the description of the following embodiments, unless otherwise indicated, the term "part" is based on mass.

[0167] <Manufacturing of Particle 1>

[0168] Step (1)

[0169] Under a nitrogen atmosphere, 5.46 parts of phthalonitrile and 45 parts of α-chloronaphthalene were added to a reactor. The mixture was then heated to 30°C and maintained at that temperature. Next, at this temperature (30°C), 3.75 parts of gallium trichloride were added to the mixture. The water concentration of the mixture at the time of addition was 150 ppm. The temperature of the mixture was then raised to 200°C. The mixture was then reacted at 200°C for 4.5 hours under a nitrogen atmosphere, followed by cooling. The product was filtered when the temperature reached 150°C. The resulting filtrate was dispersed and washed with N,N-dimethylformamide at 140°C for 2 hours, followed by filtration. The resulting filtrate was washed with methanol and then dried to obtain gallium chlorophthalocyanine particles in 71% yield.

[0170] Step (2)

[0171] 4.65 parts of gallium chlorophthalocyanine particles were dissolved in 139.5 parts of concentrated sulfuric acid at 10°C. The solution was then added dropwise to 620 parts of ice water with stirring, causing the particles to recrystallize. The solution was then filtered under reduced pressure using a filter press. A No. 5C filter (manufactured by Advantec Toyo Kaisha, Ltd.) was used as the filter. The resulting wet filter cake (filtrate) was dispersed and washed with 2% ammonia for 30 minutes, and then filtered again using a filter press. Next, the resulting wet filter cake (filtrate) was dispersed and washed with deionized water, and then filtered three more times using a filter press. Finally, the filtrate was freeze-dried to obtain hydroxy gallium phthalocyanine particles (hydrated hydroxy gallium phthalocyanine particles) with a solid content of 23% by mass in 71% yield. The hydroxy gallium phthalocyanine particles were dried using a hyper-dry dryer (trade name: HD-06R, frequency (oscillation frequency): 2,455 MHz ± 15 MHz, manufactured by Biocon (Japan) Ltd.). Thus, hydroxy gallium phthalocyanine (OHGaPc) particles (crystals) with a water content of less than 1.0% by mass were obtained.

[0172] Step (3)

[0173] Five parts of hydroxygallium phthalocyanine particles were mixed with five parts of N-methylformamide solvent, and the mixture was dispersed for 6 hours in a sand mill (TSG-1 / 4G-4U, manufactured by Igarashi Machine Production Co., Ltd. (now AIMEX Co., Ltd.), with a disc diameter of 70 mm and five discs) containing five parts of glass beads. The mixture was then filtered and dried to obtain particle 1 (specific gravity: 1.6).

[0174] <Production of Resin Solution 1>

[0175] 1.0 g of polyvinyl acetal resin (product name: BM-2, manufactured by Sekisui Chemical Co., Ltd., glass transition temperature: 71°C) was dissolved in 19 g of 2-propanol by stirring for 24 hours to provide resin solution 1.

[0176] <Production of Resin Solution 2>

[0177] 1.0 g of polyvinyl acetal resin (product name: BX-1, manufactured by Sekisui Chemical Co., Ltd., glass transition temperature: 95°C) was dissolved in 19 g of 2-propanol by stirring for 24 hours to provide resin solution 2.

[0178] <Production of Resin Solution 3>

[0179] 1.0 g of poly(methyl methacrylate) (PMMA, manufactured by Sigma-Aldrich LLC, glass transition temperature: 100 °C) was dissolved in 19 g of chlorobenzene by stirring for 24 hours to provide resin solution 3.

[0180] <Production of Resin Solution 4>

[0181] 1.0 g of poly(4-vinylpyridine) (glass transition temperature: 137 °C) was dissolved in 19 g of 2-propanol by stirring for 24 hours to provide resin solution 4.

[0182] <Production of Resin Solution 5>

[0183] 1.0 g of poly(3-hexylthiophene-2,5-dimethyl) (P3HT, glass transition temperature: 150°C<) was dissolved in 19 g of chlorobenzene by stirring for 24 hours to provide resin solution 5.

[0184] <Production of Resin Solution 6>

[0185] 1.0 g of poly[9,9-bis(2-ethylhexyl)-9H-fluorene-2,7-diyl] (glass transition temperature: 45 °C) was dissolved in 19 g of chlorobenzene by stirring for 24 hours to provide resin solution 6.

[0186] (Example 1)

[0187] [Formation of the electron transport layer]

[0188] The glass substrate containing ITO was washed, and a five-fold diluted tin(II) colloidal solution (15% water dispersion, manufactured by Alfa Aesar) was spin-coated onto it. The substrate was then heated at 150°C for 30 minutes to form an electron transport layer as a thin film with a thickness of 16 nm.

[0189] [Formation of the photoelectric conversion layer]

[0190] A photoelectric conversion layer coating solution was prepared by dissolving 1.1 g of lead iodide and 0.39 g of methyl ammonium iodide in 0.36 g of N,N-dimethylformamide and 1.45 g of dimethyl sulfoxide. This coating solution was then spin-coated onto the electron transport layer to form a 500 nm thick photoelectric conversion layer composed of MAPbI3.

[0191] [Preparation of the composition and formation of the charge transport layer]

[0192] 0.1 g of particle 1 and 0.01 g of calixarene compound (a mixture of calixarene compounds represented by formulas [C-1] to [C-4]) were mixed with 10.6 g of 2-propanol. 11 g of beads (zirconia beads, TORAYCERAM (trademark) zirconia beads, 0.3 mm) were added to the mixture, and the mixture was dispersed for 3 hours using a coating shaker (manufactured by Toyo Seiki Seisaku-sho, Ltd.) to obtain a dispersion. Then, 0.2 g of resin solution 1 (added later) was added to this dispersion, and the mixture was again dispersed using a coating shaker for 4 hours to prepare the charge transport layer coating solution. This charge transport layer coating solution was then spin-coated onto the photoelectric conversion layer to form a charge transport layer with a thickness of 180 nm.

[0193] [Introduction of the second charge transport layer]

[0194] 0.15 g of Spiro-OMeTAD, serving as the material for the second charge transport layer, was dissolved in 2.2 g of chlorobenzene. 36 μL of an acetonitrile solution obtained by dissolving 0.2 g of lithium bis(trifluoromethanesulfonyl)imide in 0.3 g of acetonitrile and 60 μL of 4-tert-butylpyridine (TBP) were added to this chlorobenzene solution, and the contents were mixed. Further, 58 μL of an acetonitrile solution obtained by dissolving 0.11 g of [tris(2-(1H-pyrazol-1-yl)-4-tert-butylpyridine)cobalt(III)tris(bis(trifluoromethanesulfonyl)imide)] in 0.3 g of acetonitrile was mixed in to prepare a material solution for the second charge transport layer. This material solution was then spin-coated onto the charge transport layer to form a second charge transport layer with a thickness of 150 nm. It was confirmed that in the X-ray diffraction spectrum of the film using CuKα rays, the ratio of the peak intensity in the range of Bragg angle 2θ above 7.6° and below 8.6° to the total peak intensity in the range of above 0.0° and below 30.0° was 0.023.

[0195] [Formation of the first electrode]

[0196] A layer with a thickness of 80 nm and an area of ​​0.09 cm² was formed on the second charge transport layer using vacuum vapor deposition. 2 Gold electrodes are used to obtain photoelectric conversion elements.

[0197] [Particle size analysis of the composition]

[0198] The particle size of the pigment particles in the composition used as the charge transport layer coating liquid was determined by measuring the Z-average particle size using the aforementioned Zetasizer Nano ZS (manufactured by Malvern Panalytical Ltd.). Initially, the composition was measured within 3 days of preparation. For measurements after 3 months, the composition, after being stored in a sealed container, was measured after thoroughly shaking the container until no sediment was observed at the bottom.

[0199] [Evaluation of photoelectric conversion efficiency]

[0200] A power supply (model 236, manufactured by Keithley Instruments) was connected between the electrodes of the photoelectric conversion element produced in Example 1, using an intensity of 100 mW / cm². 2 A solar simulator (manufactured by Yamashita Denso Corporation) was used to illuminate the element with constant light, and the resulting current and voltage were measured to determine its photoelectric conversion efficiency. The results are shown in Table 2.

[0201] (Comparative Example 1)

[0202] Except for the method of preparing the composition as a charge transport layer coating solution, the composition and photoelectric conversion element were obtained in the same manner as in Example 1. The preparation method of the composition is as follows. 0.1 g of particles 1, 0.00468 g (0.15 times the amount of resin) of calixarene compound (a mixture of compounds represented by formulas [C-1] to [C-4]), 2.2 g of cyclohexanone, and 0.03 g of BX-1 resin were mixed. Beads (glass beads, 1 mm) were added to the mixture and dispersed for 6 hours using a coating shaker (manufactured by Toyo Seiki Seisaku-sho, Ltd.) to provide a dispersion. Then, 2.2 g of ethyl acetate was added to the dispersion to dilute the liquid. It was confirmed that the ratio of the intensity of the peak in the range of Bragg angle 2θ of 7.6° to 8.6° to the total peak intensity in the range of 0.0° to 30.0° in the X-ray diffraction spectrum of the film using CuKα rays was 0.015.

[0203] (Examples 2-29 and Comparative Examples 2-6)

[0204] Except for variations in the type of calixarene compound, the ratio of calixarene compound to resin, the type of cyclic conjugated compound, the type of resin, the type of solvent, the timing of resin addition, the ratio of pigment to resin, and whether a second charge transport layer is formed during element formation, the composition and photoelectric conversion element were manufactured and evaluated in the same manner as in Example 1. The results are shown in Table 2.

[0205] The types of calixarene compounds (types of dispersants) [C-5]~[C-9] are shown below.

[0206] [Chemical Formula 8]

[0207]

[0208] [Chemical Formula 9]

[0209]

[0210] [Chemical Formula 10]

[0211]

[0212] [Chemical Formula 11]

[0213]

[0214] [Chemical Formula 12]

[0215]

[0216] In the “Resin Addition Timing” section of Table 2 of Examples 25 and Comparative Example 2, the term “pre-addition” means that in the preparation of the composition, resin solution 1 is added together with particles 1, calixarene compound and solvent from the beginning and dispersed with a coating shaker for 7 hours to provide a charge transport layer coating liquid.

[0217] [Table 2]

[0218]

[0219] This invention is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the spirit and scope of the invention. Therefore, the claims are appended to disclose the scope of the invention.

[0220] This application references Japanese patent applications filed on October 27, 2023: No. 2023-184761, No. 2023-184756, No. 2023-184750, No. 2023-216294, No. 2023-216296, No. 2023-216299, and No. 2024-022244, filed on February 16, 2024. The following patent applications, filed on February 16, 2024: 2024-022251, 2024-022246, 2024-177315, 2024-1024, and 2024-186707, are hereby cited as priority, and the entire contents of these patent applications are incorporated herein by reference.

[0221] Explanation of reference numerals in the attached figures

[0222] 1 Photoelectric conversion element

[0223] 2 substrates

[0224] 3 Second electrode

[0225] 4 Electron transport layer

[0226] 5 Photoelectric conversion layer

[0227] 6 charge transport layer

[0228] 7 First Electrode

[0229] 30 moving bodies

[0230] 31, 41 photoelectric conversion elements

[0231] 32 fuselage

[0232] 40 Building Materials

[0233] 42 Protective components

[0234] 43 Heat dissipation components

[0235] 44a, 44b Exterior

Claims

1. A composition comprising: Pigments that are cyclic conjugated compounds in which multiple pyrrole rings are linked by conjugated bonds; Dispersant; Resin; and Solvent, The dispersant is a calixarene compound represented by formula [A], and The mass of the dispersant in the composition is more than 0.20 times the mass of the resin in the composition. [Chemical Formula 1] In formula [A], R 1 ~R 5 Each repeating unit is independent, and each of the "n" repeating units is independent, as follows: R 1 Indicates a hydrogen atom or an alkyl group; R 2 Indicates substituted or unsubstituted alkylene groups; R 3 ~R 5 Each represents a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted -Y-Ar group, a substituted or unsubstituted aromatic hydrocarbon group, or a substituted or unsubstituted heterocyclic group, and R 3 ~R 5 At least one of them represents a substituted or unsubstituted -Y-Ar group, wherein -Y- in the -Y-Ar group represents -CH=N-, -CH=CH- or -N=N-, Ar represents a substituted or unsubstituted aromatic hydrocarbon group or a substituted or unsubstituted heterocyclic group, and "n" represents an integer of 3 or more and 20 or less.

2. The composition according to claim 1, wherein in formula [A], "n" means 4 or more and 8 or less.

3. The composition according to claim 1 or 2, wherein in formula [A], R 4 Each of the "n" repeating units independently represents either nitrophenylazo or dinitrophenylazo.

4. The composition according to any one of claims 1 to 3, wherein the molecular weight of the calixarene compound represented by formula [A] is less than 10,000.

5. The composition according to any one of claims 1 to 4, wherein the calixarene compound represented by formula [A] comprises at least one compound selected from the group consisting of compounds represented by formulas [C-1], [C-2], [C-3], and [C-4]: [Chemical Formula 2] [Chemical Formula 3] [Chemical Formula 4] [Chemical Formula 5] 。 6. The composition according to any one of claims 1 to 5, wherein the pigment, as a cyclic conjugated compound in which a plurality of pyrrole rings are linked by conjugated bonds, is a phthalocyanine compound.

7. The composition according to claim 6, wherein the central element of the phthalocyanine compound is metal-free or is at least one of gallium, aluminum, titanium, iron or silicon.

8. The composition according to claim 6, wherein the phthalocyanine compound is a gallium phthalocyanine compound.

9. The composition according to claim 8, wherein the gallium phthalocyanine compound is hydroxygallium phthalocyanine.

10. The composition according to any one of claims 1 to 9, wherein the resin is a resin having Lewis basic functional groups.

11. The composition according to any one of claims 1 to 10, wherein the resin has at least one functional group selected from the group consisting of hydroxyl, carbonyl, ether, ester, pyridyl, and thiophene.

12. The composition according to any one of claims 1 to 11, wherein the glass transition temperature Tg of the resin is below 95°C.

13. The composition according to claim 11 or 12, wherein the resin is polyvinyl acetal resin or polyvinyl butyral resin.

14. The composition according to any one of claims 1 to 13, wherein the solvent has a vapor pressure of 0.06 kPa or higher at 20°C.

15. The composition according to any one of claims 1 to 14, wherein the mass of the dispersant in the composition is more than 0.01 times and less than 0.50 times the mass of the pigment in the composition.

16. The composition according to any one of claims 1 to 15, wherein the mass of the pigment in the composition is more than 5 times and less than 20 times the mass of the resin in the composition.

17. A method for preparing a composition, said composition comprising: a pigment, a dispersant, a resin, and a solvent as a cyclic conjugated compound in which a plurality of pyrrole rings are linked by conjugated bonds. The dispersant is a calixarene compound represented by formula [A]. The dispersant in the composition has a mass ratio of at least 0.20 times that of the resin in the composition, and The method includes: The pigment and the dispersant are dispersed together with the solvent to provide a dispersion, and then the resin is added to the dispersion to further disperse the pigment, the dispersant, and the resin. [Chemical Formula 6] In formula [A], R 1 ~R 5 Each repeating unit is independent, and each of the "n" repeating units is independent, as follows: R 1 Indicates a hydrogen atom or an alkyl group; R 2 Indicates substituted or unsubstituted alkylene groups; R 3 ~R 5 Each represents a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted -Y-Ar group, a substituted or unsubstituted aromatic hydrocarbon group, or a substituted or unsubstituted heterocyclic group, and R 3 ~R 5 At least one of them represents a substituted or unsubstituted -Y-Ar group, wherein -Y- in the -Y-Ar group represents -CH=N-, -CH=CH- or -N=N-, Ar represents a substituted or unsubstituted aromatic hydrocarbon group or a substituted or unsubstituted heterocyclic group, and "n" represents an integer of 3 or more and 20 or less.

18. The composition according to any one of claims 1 to 16, wherein the pigment has a particle size of 1.0 × 10⁻⁶. 1 nm or larger and 5.0 × 10 2 Below nm.

19. A photoelectric conversion element comprising: First electrode; A photoelectric conversion layer containing crystals with a perovskite structure; Charge transport layer; and Second electrode, The photoelectric conversion element includes a charge transport layer between the photoelectric conversion layer and the first electrode, the charge transport layer being formed using the composition of any one of claims 1 to 16 or 18.

20. The photoelectric conversion element according to claim 19, wherein the photoelectric conversion element further comprises a second charge transport layer between the first electrode and the charge transport layer.

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