Composition, method for preparing composition and photoelectric conversion element

Abstract

To provide a composition, which improves the dispersion stability of the composition and the photoelectric conversion efficiency of a photoelectric conversion element using the composition.SOLUTION: A composition contains pigment that is a cyclic conjugated compound with a plurality of pyrrole rings conjugated together, dispersing agent, resin, and solvent, and the dispersing agent contains a calixarene compound having four -CH=N-, -CH=CH- or -N=N- moieties, and the mass of the dispersing agent in the composition is more than 0.20 times the mass of the resin in the composition.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a composition, a method for preparing the composition, and a photoelectric conversion device. [Background technology]

[0002] In order to solve the problem of fossil energy depletion and the global environmental problems caused by the use of fossil energy, active research is being conducted on renewable and clean alternative energy sources such as solar energy, wind power, and hydroelectric power. Among them, interest in solar cells that directly convert sunlight into electrical energy is increasing. Here, a solar cell refers to a cell that generates a current and voltage by utilizing the photovoltaic effect in which light energy from sunlight is absorbed and electrons and holes are generated.

[0003] Currently, np diode type silicon (Si) single crystal-based solar cells with a light energy conversion efficiency of over 20% are widely known and are actually used for photovoltaic power generation. However, these require high-temperature processing and the materials themselves are expensive, so they have the problem of high cost per unit of power. In addition, there are problems with supply in terms of silicon resources.

[0004] On the other hand, solar cells using organic materials (hereinafter referred to as "organic solar cells") do not require high-temperature processing and can be produced by the so-called roll-to-roll method using sheet-shaped substrates, which is expected to reduce costs. However, further improvement in power generation efficiency and durability is desired for practical use of organic solar cells. In particular, perovskite-type solar cells having crystals with a perovskite structure as a photoelectric conversion layer have excellent photoelectric conversion characteristics, so development is being advanced toward practical use of solar cells. For example, Patent Document 1 describes a technology for improving photoelectric conversion efficiency by forming a layer containing a phthalocyanine compound between a hole transport layer and perovskite. Patent Document 2 describes a technology for maintaining conversion efficiency for a long period of time by forming a layer containing a phthalocyanine compound and an aromatic ring compound having a hydroxyl group between a hole transport layer and perovskite. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2022-168820 [Patent Document 2] JP 2024-60579 A Summary of the Invention [Problem to be solved by the invention]

[0006] According to the studies of the present inventors, it has been found that the compositions described in Patent Documents 1 and 2 still have room for improvement in terms of dispersion stability of the compositions and photoelectric conversion efficiency of the photoelectric conversion element. Therefore, an object of the present invention is to provide a composition which improves the dispersion stability of the composition and the photoelectric conversion efficiency of a photoelectric conversion element using the composition. [Means for solving the problem]

[0007] The above object can be achieved by the present invention, which is described below. That is, the present invention provides a composition containing a pigment that is a cyclic conjugated compound in which a plurality of pyrrole rings are conjugatedly bonded, a dispersant, a resin, and a solvent, The dispersant is a calixarene compound represented by the following formula [A], The composition is characterized in that the mass of the dispersant in the composition is 0.20 times or more the mass of the resin in the composition. [ka] (In the above formula [A], R 1 ~R 5 R 1 represents a hydrogen atom or an alkyl group, R 2 represents a substituted or unsubstituted alkyl group, R 3 ~R 5represents 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 ring, and at least one of them is a substituted or unsubstituted -Y-Ar group. -Y- in the -Y-Ar group represents -CH=N-, -CH=CH-, or -N=N-, and Ar represents a substituted or unsubstituted aromatic hydrocarbon group, or a substituted or unsubstituted heterocyclic group. n is an integer of 3 to 20. Effect of the Invention

[0008] According to the present invention, the dispersion stability of the composition is improved, and the photoelectric conversion efficiency of a photoelectric conversion element using the composition as a coating liquid for a charge transport layer can be improved. [Brief description of the drawings]

[0009] [Figure 1] 1 is a schematic cross-sectional view in the thickness direction of a photoelectric conversion element of the present invention. [Diagram 2] FIG. 1 is a perspective view showing a schematic diagram of an example of a moving body including a photoelectric conversion element according to the present invention. [Diagram 3] FIG. 1 is a perspective view illustrating an example of a building material including a photoelectric conversion element of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The composition of the present invention comprises A composition comprising a pigment which is a cyclic conjugated compound in which a plurality of pyrrole rings are conjugatedly bonded, a dispersant, a resin, and a solvent, The dispersant is a calixarene compound represented by the following formula [A], The composition is characterized in that the mass of the dispersant in the composition is 0.20 times or more the mass of the resin in the composition. [ka] (In the formula [A], R 1 ~R 5R 1 represents a hydrogen atom or an alkyl group, R 2 represents a substituted or unsubstituted alkylene group, R 3 ~R 5 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 at least one of them is a substituted or unsubstituted -Y-Ar group. -Y- in the -Y-Ar group represents -CH=N-, -CH=CH-, or -N=N-, and Ar represents a substituted or unsubstituted aromatic hydrocarbon group, or a substituted or unsubstituted heterocyclic group. n is an integer of 3 to 20.

[0011] As a result of investigation, the present inventors have found that the dispersion stability of the above composition and the photoelectric conversion efficiency of a photoelectric conversion element using the composition as a charge transport layer coating liquid can be improved. Although the details of the reason why the dispersion stability of the composition and the photoelectric conversion efficiency of a photoelectric conversion element using the composition as a charge transport layer coating liquid can be improved in the present invention are not clear, the mechanism is considered to be as follows. In this specification, the dispersion stability specifically means that the particle diameter of the pigment particles in the composition after dispersion is 1.0×10 1 nm or more 5.0×10 2 This means that the level of the serotonin produced is less than 1 nm and persists for a long period of time, at least three months.

[0012] The particle size of the composition can be measured using a Zetasizer Nano-ZS (manufactured by MALVERN). This device can measure particle size by dynamic light scattering. First, the composition is diluted and prepared so that the solid-liquid ratio of the particles to be measured is 0.10% by mass (±0.02% by mass), and then the composition is collected in a quartz cell and placed in the measurement section. The dilution liquid is prepared and used as the same liquid as the solvent that constitutes the charge transport layer coating liquid. As the measurement conditions, the refractive index and viscosity of the dispersion solvent at 20°C are input using the control software Zetasizer software 6.30, and measurements are performed under conditions where the liquid is 20°C, to obtain the Z-average particle size. In the case of a mixed solvent, the weight average value of the dispersion medium to be mixed is adopted.

[0013] According to prior art documents, when a photoelectric conversion layer contains crystals with a perovskite structure, submicron irregularities are generated on the surface. It is presumed that filling the concave portions of the irregularities with pigment particles made of a phthalocyanine compound, which is a type of cyclic compound formed by conjugating multiple pyrrole rings, stabilizes the interface bond with the electrode and allows high photoelectric conversion efficiency to be obtained. However, it was found that there is still room for improvement in the dispersion stability of the composition and in the photoelectric conversion efficiency of a photoelectric conversion element using the composition as a charge transport layer coating liquid.

[0014] The present inventors presume that the pigment composition is composed of a solvent, a cyclic conjugated compound formed by conjugating multiple pyrrole rings, a calixarene compound represented by the following formula [A] as a dispersant, and a resin, and that the mass of the dispersant in the composition is 0.20 times or more the mass of the resin in the composition, which contributes to the dispersion stability of the pigment particles in the composition and to higher photoelectric conversion efficiency when a photoelectric conversion element is produced using the composition as a charge transport layer coating liquid.

[0015] Dispersion stability is enhanced by the interaction between the cyclic compound formed by conjugating multiple pyrrole rings, the calixarene compound represented by the above formula [A], the resin, and the solvent. This is because the hydrophobic part of the calixarene compound (R 3 , R 4, R 5 The hydrophilic side (R 1 It is presumed that this is due to the interaction of the dispersant (the polymer side) with the resin and solvent, and that the dispersion stability of the pigment particles is poor if either the dispersant or the resin is missing.

[0016] 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 desired that the cyclic compound formed by conjugated bonds of pyrrole rings and the calixarene compound represented by the above formula [A] interact preferentially, the resin interacts with the cyclic compound formed by conjugated bonds of pyrrole rings more than necessary, and compared to when the mass is 0.20 times or more, the pigment particles are less uniformly dispersed, the tendency to aggregate increases, and the dispersion stability deteriorates. With regard to the efficiency when made into a photoelectric conversion element, it is presumed that as a result of the deterioration in dispersion stability, when the perovskite is coated with the perovskite, there are more areas where the perovskite is not filled with particles of a cyclic compound in which multiple pyrrole rings are conjugated, making the interfacial junction more unstable and ultimately reducing the photoelectric conversion efficiency.

[0017] As explained by the above mechanism, it is believed that the synergistic effects of each component result in good dispersion stability of the pigment particle composition and dense packing of the perovskite, stabilizing the interfacial bond with the electrode and improving the photoelectric conversion efficiency.

[0018] In the composition of the present invention, the solvent is a solvent that does not destroy the perovskite crystals. A method for selecting a solvent that does not destroy the perovskite crystals is to apply the solvent to a perovskite coating film and leave it for 1 hour to confirm that the perovskite crystals are not destroyed, specifically, that the density and color of the film are not changed.

[0019] In addition, since the solvent needs to be dried quickly after being applied to the perovskite, a vapor pressure (20°C) of 0.06 kPa or more is preferable. By drying quickly, defects such as particles coagulating and not being able to completely cover the perovskite can be reduced. If the above conditions are met when two or more types are mixed, they can be used as a mixed solvent. In the case of two or more types, the vapor pressure is confirmed by adding up the product of the vapor pressure of each solvent and the weight ratio in the mixed solvent. Specific examples of solvents are not limited as long as they do not destroy the perovskite crystals and meet the above two conditions of vapor pressure, but include hydrocarbons, esters, ketones, ethers, aromatic compounds, and alcohols. However, it is preferable that the main solvent is alcohol-based from the viewpoint of dispersion stability and meets the above conditions.

[0020] In the composition of the present invention, the pigment, a cyclic compound formed by conjugating multiple pyrrole rings, is dispersed in a coating liquid and exists in a particulate state. By forming a film in a particulate state, high crystallinity is maintained and the inherent high charge transport ability can be expressed.

[0021] Specific examples of the cyclic compound in which a plurality of pyrrole rings are conjugated to each other in the present invention are given below. Porphyrin derivatives such as tetraphenylporphyrin, diphenylporphyrin, tetrapyridylporphyrin, copper porphyrin, copper tetraphenylporphyrin, copper octaethylporphyrin, cobalt tetraphenylporphyrin, octaethylporphyrin, chlorophenylporphyrin, methoxyphenylporphyrin, methylphenylporphyrin, zinc porphyrin, magnesium porphyrin, octabutoxyporphyrin, manganese chloroporphyrin, metal-free tetraazaporphyrin, copper tetraazaporphyrin, zinc tetraazaporphyrin, nickel tetraazaporphyrin, titanyl tetraazaporphyrin, tetraphenyltetraazaporphyrin, and octaphenyltetraazaporphyrin. Phthalocyanine derivatives such as hydroxygallium phthalocyanine, chlorogallium phthalocyanine, copper phthalocyanine, zinc phthalocyanine, phthalocyanine, cobalt phthalocyanine, titanyl phthalocyanine, dichlorotin phthalocyanine, magnesium phthalocyanine, tin phthalocyanine, lead phthalocyanine, iron phthalocyanine, vanadyl phthalocyanine, chloroaluminum phthalocyanine, nickel phthalocyanine, dichlorosilicon phthalocyanine, indium chlorophthalocyanine, manganese phthalocyanine, chloroiron phthalocyanine, and platinum phthalocyanine. Naphthalocyanine derivatives such as naphthalocyanine, magnesium naphthalocyanine, copper naphthalocyanine, magnesium naphthalocyanine, cobalt naphthalocyanine, vanadyl naphthalocyanine, tin naphthalocyanine, and dichlorotin naphthalocyanine.

[0022] In the present invention, from the viewpoint of the spread of the π electron cloud which is the starting point of the interaction with the perovskite, a porphyrin compound or a phthalocyanine compound is preferred, and a phthalocyanine compound is more preferred. The central element of the phthalocyanine compound is preferably non-metallic or at least one of gallium, aluminum, titanium, iron, and silicon. The phthalocyanine compound is particularly preferably phthalocyanine, gallium phthalocyanine, titanyl phthalocyanine, aluminum phthalocyanine, titanyl phthalocyanine, iron phthalocyanine, or silicon phthalocyanine. Among them, gallium phthalocyanine is more preferred, and hydroxygallium phthalocyanine is particularly preferred. In addition, from the viewpoint of electronic interaction, it is preferable that the X-ray diffraction spectrum of the film of the composition is measured, and the ratio of the peak intensity within the range of the Bragg angle 2θ of 7.6° to 8.6° to the total peak intensity of 0.0° to 30.0° is 0.02 or more. In the present invention, the chemical structure of a cyclic conjugated compound formed by conjugating a plurality of pyrrole rings can be confirmed, for example, by nuclear magnetic resonance (NMR).

[0023] In the composition of the present invention, the dispersant is a calixarene compound represented by the following formula [A]. [ka] (In the formula [A], R 1 ~R 5 R 1 represents a hydrogen atom or an alkyl group, R 2 represents a substituted or unsubstituted alkylene group, R 3 ~R 5 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 ring, and at least one of them is a substituted or unsubstituted -Y-Ar group. -Y- in the -Y-Ar group represents -CH=N-, -CH=CH-, or -N=N-, and Ar represents a substituted or unsubstituted aromatic hydrocarbon group, or a substituted or unsubstituted heterocyclic group. n is an integer of 3 to 20.

[0024] Above R 1 ~R 5 Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, and a butyl group. R 3 ~R 5 Examples of the aromatic hydrocarbons mentioned above include benzene, naphthalene, fluorene, phenanthrene, anthracene, fluoranthene, and pyrene. Also, R 3 ~R 5 Examples of the heterocycles mentioned above include furan, thiophene, pyridine, indole, benzothiazole, carbazole, benzocarbazole, acridone, dibenzothiophene, benzoxazole, benzotriazole, oxathiazole, thiazole, phenazine, cinnoline, and benzocinnoline. Also, R 2 ~R 5Examples of the substituent that the alkyl group, phenylazo group, aromatic hydrocarbon group, and heterocycle mentioned above may have include alkyl groups such as a methyl group, an ethyl group, a propyl group, and a butyl group; alkoxy groups such as a methoxy group and an ethoxy group; dialkylamino groups such as a dimethylamino group and a diethylamino group; alkoxycarbonyl groups such as a methoxycarbonyl group and an ethoxycarbonyl group; halogen atoms such as a fluorine atom, a chlorine atom, and a bromine atom; a hydroxy group, a nitro group, a cyano group, and a halomethyl group.

[0025] In the aromatic ring compound having a calixarene structure represented by the above formula [A], in terms of molecular size, in order to easily improve dispersion stability, it is preferable that n is 4 or more and 8 or less, and the molecular weight is 10,000 or less.

[0026] In the present invention, R 1 is preferably a hydrogen atom, a methyl group, an ethyl group, or a propyl group for each of the n repeating units. 2 is preferably a methylene group, an ethylene group, or a trimethylene group, independently for each of the n repeating units. 3 , R 5 is a hydrogen atom, R 4 is preferably a nitrophenylazo group or a dinitrophenylazo group, independently for every n repeating units.

[0027] Among them, specific examples of calixarene compounds that are particularly preferably used in the present invention are listed below. In the present invention, the dispersant preferably contains at least one selected from the group consisting of a compound represented by the following formula [C-1], a compound represented by the following formula [C-2], a compound represented by the following formula [C-3], and a compound represented by the following formula [C-4], and more preferably contains all four (a mixture). [ka] [ka] [ka] [ka]

[0028] In the present invention, the chemical structure of the aromatic ring compound having a calixarene structure represented by formula [A] can be confirmed by, for example, nuclear magnetic resonance (NMR) spectroscopy. From the viewpoint of dispersion stability of the pigment particles, it is preferable that the mass of the dispersant in the composition of the present invention is 0.01 to 0.50 times the mass of the pigment particles, which are cyclic compounds formed by conjugating multiple pyrrole rings in the composition.

[0029] Specific examples of the resin in the composition of the present invention include polyacetal resin, acrylic resin, polyarylate resin, polycarbonate resin, polyvinyl acetate resin, polyester resin, polyamide resin, polyurethane resin, and polystyrene resin.

[0030] The resin is preferably a resin having a Lewis basic functional group. The Lewis basic functional group acts electronically on the pigment particles, which are cyclic compounds formed by conjugating multiple pyrrole rings, and the dispersant, which is a calixarene compound, to enhance the interaction between the pigment particles and the resin, making it easier for the resin to intervene between the particles, and making it easier to obtain the effect of steric barrier stabilization by the resin.

[0031] Specifically, the Lewis basic functional group includes a hydroxy group, a halogen, a sulfo group, an amino group, a carbonyl group, an ester bond, an ether bond, a carboxyl group, an aldehyde group, a methoxy group, an amide group, a sulfide group, a cyano group, a thienyl group, a pyridyl group, a furan, a pyrazole, an imidazole, an oxazole, and a thiazole. Among them, a hydroxy group, a carbonyl group, an ether bond, an ester bond, a pyridyl group, and a thienyl group are preferable from the viewpoint of electronic interaction. In particular, it is more preferable to have at least two functional groups from among these groups in terms of ease of interaction. Different functional groups may be present in one resin, or two resins having different functional groups may be mixed. It is preferable that the Lewis basic functional group is present in the repeating structure of the resin.

[0032] Specific examples of the resin having a Lewis basic functional group that can be preferably used in the present invention are given below. 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, poly(sodium 4-styrenesulfonate), poly(allylamine hydrochloride), sodium polyacrylate, poly(allylamine hydrochloride), poly(4-styrenesulfonic acid), poly(N-isopropylacrylamide), poly(2-ethyl-2-oxazoline), poly(ethylene-alt-maleic anhydride), poly(2-acrylamido-2-methyl-1-propanesulfonic acid), poly(vinyl sulfate) potassium salt, polyanethol sulfonic acid sodium salt, poly(2-dimethylamino)ethyl methacrylate) methyl chloride quaternary salt, poly(methyl vinyl ether), poly(2-propyl acrylic acid), 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-butylene adipate), poly(4-vinylphenol), poly(propylene glycol) monobutyl ether, poly Preferred are poly(glycidyl methacrylate), polybutyl acrylate, poly(ethylene succinate), poly(propylene glycol) methacrylate, nylon 11, nylon 12, poly(2-ethylhexyl acrylate), poly(bisphenol A carbonate), poly(propylene glycol) bis(2-aminopropyl ether), polyetherimide, poly(vinyl formal), poly(vinyl methyl ketone), poly(3-hexylthiophene-2,5-diyl), polyaniline, and a composite of poly(3,4-ethylenedioxythiophene) and polystyrene sulfonate (PEDOT:PSS).Among these, polyvinyl butyral, polymethyl methacrylate, poly(3-hexylthiophene-2,5-diyl), polyvinyl acetate, polyvinyl alcohol, polyacrylic acid, poly(2-propylacrylic acid), polybutyl acrylate, and poly(4-vinylpyridine) are more preferred from the viewpoint of electronic interaction, and polyvinyl acetal resins and polyvinyl butyral resins are particularly preferred. These resins are likely to interact with pigment particles, which are cyclic compounds formed by conjugating multiple pyrrole rings.

[0033] It is more preferable that the glass transition temperature (Tg) of the resin is 95° C. or less. If the resin has a glass transition temperature in this range, the resin can easily come into close contact with the pigment particles, which are charge transport particles, and the coating property can be improved more effectively by the interaction. The glass transition temperature can be determined by a differential scanning calorimeter (DSC). The molecular weight of the resin is preferably in the range of 1,000 to 1,000,000 in terms of dispersibility and film-forming properties.

[0034] It is preferable that the mass of the pigment particles, which are cyclic compounds formed by conjugating multiple pyrrole rings in the composition of the present invention, is 5 to 20 times the mass of the resin in the composition, since the resin easily interacts with the pigment particles and the covering property is easily improved. If it is more than 20 times, the improvement in covering property due to the interaction of the resin is likely to be insufficient. If it is less than 5 times, the charge transfer from the photoelectric conversion layer to the particles is insufficient, making it difficult to improve the photoelectric conversion efficiency.

[0035] Methods for dispersing the composition of the present invention include methods using a paint shaker, a sand mill, a ball mill, and a liquid collision type high-speed disperser. Among these, a sand mill disperses the material by the rotation of a disk rotating inside the mill and the shear force caused by media such as glass beads as a grinding medium, and the dispersion stability can be changed by changing the dispersion conditions such as the dispersion time, amount of beads, disk rotation speed, and timing of adding each material.

[0036] In the preparation of the composition of the present invention, particularly in the process of producing the composition, the timing of adding the resin is such that, rather than adding it together with the pigment, dispersant, and solvent at the start of dispersion, the pigment, dispersant, and solvent are first dispersed to a certain extent to obtain a dispersion (pre-dispersion), and then the resin is added to the dispersion and dispersed again, thereby improving the dispersion stability of the pigment. When the dispersion stability is improved by devising the above-mentioned manufacturing method, differences in dispersion stability that cannot be determined by the particle size measured with the Zetasizer Nano-ZS (manufactured by MALVERN) due to factors such as aggregation can be confirmed, if necessary, by imaging methods using SEM (scanning electron microscope) images or measuring the specific surface area coefficient using pulse NMR.

[0037] The measurement of the X-ray diffraction spectrum of the composition and the measurement of the content of the cyclic compound formed by conjugated bonds of a plurality of pyrrole rings are also described below. The analysis of the content of the compound amount and the X-ray diffraction measurement were performed by using a film obtained by drying the composition, or by removing the layer above the charge transport layer of a photoelectric conversion element using the composition as a charge transport layer coating liquid with an organic solvent such as chloroform, exposing the surface of the film of the composition, and performing the following method.

[0038] [Analysis of compound amounts] The surface of the composition film was wiped with a cotton swab soaked in a solvent, dissolved in heavy water sulfuric acid, and 1H-NMR measurement (apparatus: AVANCE3-500, manufactured by BRUKER) was performed. In addition, elemental analysis such as GPC, MALDI-TOF-MS, IR, gas chromatography, XPS, and EDX was performed on the wiped components. These mass and structure analyses were performed to confirm the presence of compounds and their important ratios with resins and dispersants. The film thickness was confirmed by cutting the photoelectric conversion element, fixing it to an inclined sample stage, and then observing the cross-section with a SEM (apparatus: Carl Zeiss KK, SmartSEM). MALDI-TOF-MS analysis The analysis was carried out under the following conditions, and the molecular weight was confirmed from the obtained peak top value. Measurement equipment used: Bruker Daltonics, matrix-assisted laser desorption / ionization time-of-flight mass spectrometer (MALDI-TOF MS) ultraflex Accelerating voltage: 20 kV Mode: Reflector Molecular weight standard: Fullerene C60

[0039] [X-ray diffraction measurement] The X-ray diffraction spectrum of the film of the composition was measured, and the ratio of the peak intensity within the Bragg angle 2θ range of 7.6° to 8.6° to the total peak intensity within the range of 0.0° to 30.0° was calculated. Measuring equipment used: Rigaku Electric Co., Ltd., X-ray diffraction device RINT-TTRII X-ray tube:Cu X-ray wavelength: Kα1 Tube voltage: 50KV Tube current: 300mA Scan method: 2θ-θ scan Scan speed: 0.4° / min Sampling interval: 0.005° Start angle 2θ: 3.0° Stop angle 2θ: 30.0° Goniometer: Rotor horizontal goniometer (TTR-2) Filter: None Detector: Scintillation counter Incident Monochrome: Use Slit: Variable slit (parallel beam method) Counter monochromator: Not used Divergence slit: open Divergence vertical limit slit: 10.00mm Scattering slit: open Receiving slit: open

[0040] The present invention will be described in detail below with reference to preferred embodiments. The present invention is not limited to the following embodiments, and any modifications or improvements to the following embodiments based on the ordinary knowledge of a person skilled in the art without departing from the spirit of the present invention are also included in the scope of the present invention.

[0041] In this specification, the term "layer" refers not only to a layer having a clear boundary or a flat thin-film layer, but also to a layer having a concentration gradient in which the contained elements change gradually, or to a layer that can form a complex structure together with other layers. Elemental analysis of the layer can be performed, for example, by performing TOF-SIMS / FE-TEM / EDS line analysis measurement of the cross section of the photoelectric conversion element to confirm the element distribution of a specific element. Analysis of each layer may be performed by peeling off the completed photoelectric conversion element to expose the layer to be analyzed. In addition, analysis of the compound in the charge transport coating liquid can be performed by mass and structure analysis using elemental analysis such as 1H-NMR, GPC, MALDI-TOF-MS, IR, gas chromatography, liquid chromatography, XPS, and EDX.

[0042] 1 is a cross-sectional view showing a schematic configuration of one embodiment of a photoelectric conversion element using the composition of the present invention as a charge transport layer coating liquid. A second electrode 3, an electron transport layer 4, a photoelectric conversion layer 5, a charge transport layer 6, and a first electrode 7 are provided on a substrate 2. One of the first electrode 7 and the second electrode 3 is an anode and the other is a cathode, and a current can be extracted by connecting the first electrode 7 and the second electrode 3 to an external circuit. The photoelectric conversion layer 5 is excited by light incident 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, and generates 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 a layer disposed between the photoelectric conversion layer 5 and two electrodes (the second electrode 3 and the first electrode 7), and may not be formed in some cases. A configuration in which a plurality of electron transport layers 4 and photoelectric conversion layers 5 are stacked may be used. Such a configuration may also be called a tandem structure. Each member will be described below.

[0043] [Photoelectric conversion element] The photoelectric conversion element of the present invention is characterized by having a first electrode, a second electrode, a photoelectric conversion layer containing a crystal of a perovskite structure disposed between the first electrode and the second electrode, and a charge transport layer between the photoelectric conversion layer and the first electrode. In addition, in order to improve the photoelectric conversion efficiency, the photoelectric conversion elements may be stacked in a tandem type. The photoelectric conversion elements to be stacked are not limited to the type of photoelectric conversion element, and may include a perovskite solar cell using a perovskite crystal in the photoelectric conversion layer, a silicon solar cell, a CIGS solar cell, and the like.

[0044] Examples of the method for forming each layer of the photoelectric conversion element of the present invention include a coating method and a vapor deposition method. Examples of the coating method include dip coating, spin coating, spray coating, inkjet coating, meniscus coating, screen coating, roll coating, die coating, blade coating, curtain coating, and wire bar coating. The coating method is a method in which a coating solution for each layer described below is prepared, coated in the desired layer order, and dried. A desired method can be selected from these film formation methods according to each layer. Each layer will be described below.

[0045] 〔substrate〕 The photoelectric conversion element 1 of the present invention may include a substrate 2, examples of which include a transparent glass substrate such as soda-lime glass or alkali-free glass, a ceramic substrate, a transparent plastic substrate, etc. When light is taken in from the first electrode 7 side, an opaque material can be used for the substrate 2, and when light is taken in from the second electrode 3 side, the substrate 2 is made of a transparent material.

[0046] 〔electrode〕 The material of the first electrode 7 and the second electrode 3 is not particularly limited, and a conventionally known material can be used. For example, metals such as gold, silver, titanium, and copper, sodium, sodium-potassium alloy, lithium, magnesium, carbon, aluminum, magnesium-silver mixture, magnesium-indium mixture, aluminum-lithium alloy, Al / Al2O3 mixture, and Al / LiF mixture can be mentioned. Examples of transparent electrode materials include conductive transparent materials such as CuI, ITO (indium tin oxide), SnO2, AZO (aluminum zinc oxide), IZO (indium zinc oxide), GZO (gallium zinc oxide), FTO (fluorine-doped tin oxide), and ATO (antimony-doped tin oxide), and conductive transparent polymers. These materials may be used alone, or two or more kinds may be used in combination. At least one of the electrodes on the light incident side of the first electrode 7 and the second electrode 3 is a transparent electrode, and the other may be a transparent electrode or a transparent electrode that also serves as a reflective layer formed of a light-reflective material, or a transparent electrode provided with a reflective layer on the opposite side to the light incident side. When the first electrode 7 is on the light incident side, the second electrode 3 may be a transparent electrode and the substrate 2 may be a reflective layer. The electrode may be a patterned electrode.

[0047] [Photoelectric Conversion Layer] The photoelectric conversion layer 5 has a crystal having a perovskite structure. The crystal having a perovskite structure used in the present invention is preferably represented by the following general formula [1]. ABX3[1] In the above general formula [1], A is a monovalent cation of an organic molecule or a metal atom, B is a divalent metal cation, and X is a monovalent halide anion. As A in the above general formula [1], for example, in the case of an organic molecule, C p N m H n (wherein p, m, and n are all positive integers) are preferred. Specific examples include methylammonium and formamidium. The metal atom is not particularly limited, but lithium, cesium, sodium, potassium, and rubidium are preferred. These organic molecules or metal atoms may be used alone or in combination of two or more.

[0048] When the constituent A cations are too large to fit within the 3D perovskite crystal, they form 2D perovskite crystals, 2.5D perovskite crystals with both 2D and 3D properties, bilayer crystals of 3D and 2D perovskite structures, or mixed 3D and 2D perovskite crystals, all of which function as photoelectric conversion layers. A bilayer crystal of 3D and 2D perovskite refers to a crystal in which 3D and 2D perovskite crystals are stacked as independent, separate layers, while a mixed 3D and 2D perovskite refers to a crystal with a structure in which both regions or domains of 2D or 2.5D layered and 3D perovskite crystals are mixed. The crystals having a two-dimensional perovskite or 2.5-dimensional perovskite structure are preferably represented by the following general formulas [2] to [4]. R'2A n-1 B n X 3n+1 [2] R''A n-1 B n X 3n+1 [3] R'''A n B n X 3n+1 [4] In the above general formulas, [2] forms an RP (Ruddlesden-Popper) type perovskite structure, [3] forms a DJ (Dion-Jacobson) type perovskite structure, and [4] forms an ACI (Alternating cations in the interlayer) type perovskite structure.

[0049] In the above general formulas [2] to [4], R', R'', and R''' are, for example, C p N m H n(p, m, and n are all positive integers). A may or may not have a substituent, and specifically, ethylammonium, propylammonium, n-butylammonium, n-hexylammonium, n-octylammonium, 1,6-hexadiammonium, iso-butylammonium, 3-(nonafluoro-tert-butyloxy)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, guanidium, propylammonium, propargylamine, alkylammonium, cyclohexylmethylammonium, 4-(aminomethyl)piperidinium, piperidinium, pyrrolidinium, cyclohexylammonium, 4-fluoro Phenethylammonium, 4-fluorophenethylammonium, trifluoromethylbenzylammonium, pentafluorobenzylammonium, pentafluorophenylethylammonium, 4-methoxyphenethylammonium, imidazolium, pyridinium, 3-thiophenemethylammonium, 2-thiopheneethylammonium, 2-thiopheneformamidium, 2-thiophenemethylammonium, 1-naphthylmethylammonium, 2-naphthylmethylammonium, phenethylammonium, phenylammonium, benzylammonium, 2,5-thiophenedimethylammonium, phenylpropylammonium, 1,4-phenylenedimethanamine, 3-phenyl-2-propene-1-ammonium, phenylbutylammonium, 4-tert-butyl-benzylammonium, 3-(aminomethyl)piperidinium, 4-(aminomethyl)piperidinium are preferred.

[0050] In the above general formulas [1] to [4], B is a metal atom, such as 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 may be used alone or in combination of two or more.

[0051] X in the above general formulas [1] to [4] is a halogen atom, such as chlorine, bromine, and iodine. These halogen atoms may be used alone or in combination of two or more. Among them, halogen atoms are preferred because the perovskite crystals are easily soluble in organic solvents by containing halogen in the structure, making it possible to apply the perovskite crystals to inexpensive printing methods. Furthermore, iodine is more preferred because the energy band gap of the perovskite crystals is narrowed.

[0052] Specifically, 3D perovskites, 2D perovskites, and mixed 3D / 2D perovskites are MAPbI3, FAPbCl3, FAPbI3, MAPbI 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, {Cs x1 (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、Csx(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 ,(THAT 0.9 AND 0.1 )2MA4Pb5I 16 ,(THAT 0.9 AND 0.1 )2MA3Pb4I 13 、(4FPEA)2MA3Pb4I 13 、(4FPEA)2MA4Pb5I 16 (BA)2MA2Pb3I 10, (BA)2MA3Pb4I 13 , (TEA)2MA2Pb3I 10 , (BA)2MA4Pb5I 16 , (BA)2MA3Pb4I 13 The A site, B site, or X site in the above general formula may be adjusted to be under- or over-content depending on the purpose, and the combination of x1 to x5 may be changed depending on the purpose. x1 ~ x5 The combinations are, for example, 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 may be included as a material for forming perovskite crystals.

[0053] [Table 1]

[0054] In the above specific examples, "MA" stands for methylammonium, "FA" stands for formamidinium, "PEA" stands for phenethylammonium, "PTA" stands for phenyltriethylammonium, "ThMA" stands for 2-thiophenemethylammonium, "3BBA" stands for 3-bromobenzylammonium, "3AMPY" stands for 3-(aminomethyl)pyridine, "PDMA" stands for 1,4-phenylenedimethaneammonium, "TTDMA" stands for thieno[3,2-b]thiophene-2.5-diyldimethaneammonium, "4FPEA" stands for 4-fluorine phenethylammonium, "BA" stands for butylammonium, and "TEA" stands for 2-thiophenethylammonium.

[0055] The crystal with the perovskite structure preferably has a cubic structure in which a metal atom B is located at the body center, an organic molecule A at each vertex, and a halogen atom X at the face center. Although the details are not clear, it is presumed that the presence of such a structure makes it easy to change the orientation of the octahedron in the crystal lattice, thereby increasing the mobility of electrons in the crystal with the perovskite structure and improving the photoelectric conversion efficiency of the photoelectric conversion element.

[0056] The organic-inorganic perovskite compound used in the present invention is preferably a crystalline semiconductor. The crystalline semiconductor means a semiconductor in which the scattering peak can be detected by measuring the X-ray scattering intensity distribution. By using the organic-inorganic perovskite compound as a crystalline semiconductor, the mobility of electrons in the organic-inorganic perovskite compound is increased, and the photoelectric conversion efficiency of the photoelectric conversion element is improved.

[0057] The thickness of the photoelectric conversion layer according to the present invention is preferably 5 nm or more and 2000 nm or less. If the thickness is 5 nm or more, light can be sufficiently absorbed, and if the thickness is 2000 nm or less, the generated charge can be transported to each electrode. The more preferred lower limit is 50 nm or more, the more preferred upper limit is 1200 nm, the even more preferred lower limit is 100 nm, and the even more preferred upper limit is 1000 nm.

[0058] [Charge transport layer] In the photoelectric conversion element of the present invention, a charge transport layer is disposed between a photoelectric conversion layer and a first electrode, and the charge transport layer has a charge transporting material and a resin and is disposed on the surface of the photoelectric conversion layer. The charge transport layer can be formed by preparing a coating solution for the charge transport layer, which is the above-mentioned composition, forming the coating film on the photoelectric conversion layer, and drying it. Methods for forming the coating film include dip coating, spin coating, spray coating, inkjet coating, meniscus coating, screen coating, roll coating, die coating, blade coating, curtain coating, and wire bar coating. The photoelectric conversion element of the present invention may have a second charge transport layer between the first electrode and the charge transport layer. By having the second charge transport layer, the transfer of carriers to the electrode may be facilitated. The thickness of the charge transport layer is preferably from 1 nm to 1000 nm, more preferably from 5 nm to 500 nm, and particularly preferably from 10 nm to 200 nm.

[0059] [Second Charge Transport Layer] In the present invention, from the viewpoint of film compatibility of the charge transport layer 6, a second charge transport layer may be further provided between the charge transport layer 6 and the first electrode . The material of the second charge transport layer is not particularly limited, and examples thereof include spirofluorene compounds, triphenylamine compounds, chrysene compounds, pyrene compounds, phthalocyanine compounds, carbazole compounds, fluorene compounds, phenylcyclohexane compounds, benzidine compounds, phenoxazine compounds, phenylenediamine compounds, and thiocyanate compounds. In particular, from the viewpoint of compatibility with the film interface, it is preferable that the compound has an aromatic ring, and Spiro-OMeTAD, PTAA, and phthalocyanine compounds are preferable.

[0060] [Electron transport layer] In the photoelectric conversion element of the present invention, as shown in FIG. 1, an electron transport layer 4 may be disposed between the second electrode 3 and the photoelectric conversion layer 5. The material of the electron transport layer 4 is not particularly limited, and examples thereof include N-type conductive polymers, N-type low-molecular organic semiconductors, N-type metal oxides, N-type metal sulfides, alkali metal halides, alkali metals, surfactants, etc., and specific examples thereof include cyano group-containing polyphenylene vinylene, boron-containing polymers, bathocuproine, bathophenanthrene, hydroxyquinolinatoaluminum, oxadiazole compounds, benzimidazole compounds, naphthalenetetracarboxylic acid compounds, perylene derivatives, phosphine oxide compounds, phosphine sulfide compounds, fluoro group-containing phthalocyanines, titanium oxide, zinc oxide, indium oxide, tin oxide, gallium oxide, tin sulfide, indium sulfide, zinc sulfide, etc. In particular, tin oxide may be obtained by reacting tin(2) chloride, tin(4) chloride, tin(2) chloride dihydrate, or tin(4) chloride pentahydrate. The thickness of the electron transport layer 4 is preferably 1 nm in lower limit and 2000 nm in upper limit. If the thickness is 1 nm or more, holes can be blocked sufficiently, and if the thickness is 2000 nm or less, resistance during electron transport is unlikely to occur, and photoelectric conversion efficiency is increased. The more preferable lower limit of the thickness is 3 nm, the more preferable upper limit is 1000 nm, the even more preferable lower limit is 5 nm, and the even more preferable upper limit is 500 nm.

[0061] <Application Examples> Application examples of the present invention include photoelectric conversion devices, moving objects, and building materials. [Photoelectric conversion device] The photoelectric conversion device of the present invention has the above-mentioned photoelectric conversion element. A photoelectric conversion device can be configured by using a plurality of photoelectric conversion elements of the present invention. When a plurality of photoelectric conversion elements are connected, the photoelectric conversion device can also be called a photoelectric conversion cell or a photoelectric conversion module. The photoelectric conversion element may be a stack of photoelectric conversion elements having different absorption wavelengths in order to increase the output voltage. The photoelectric conversion device also has the photoelectric conversion element of the present invention and an inverter. The inverter may be a converter that converts direct current to alternating current. The photoelectric conversion device may have a storage unit connected to the photoelectric conversion element. The storage unit is not limited as long as it can store electricity. For example, a secondary battery using lithium ions or the like, an all-solid-state battery, an electric double layer capacitor, etc. can be mentioned.

[0062] [Mobile object] The moving body of the present invention has the above-mentioned photoelectric conversion element. FIG. 2 is a perspective view showing an embodiment of a moving body equipped with the photoelectric conversion element of the present invention. The moving body 30 has the photoelectric conversion element 31 of the present invention and a vehicle 32 equipped with the photoelectric conversion element 31. The photoelectric conversion element 31 is arranged at a position where the vehicle 32 can receive external light. If the moving body 30 is an automobile, it may be arranged on the roof. The electric energy obtained by the photoelectric conversion element 31 may be used as the power of the moving body 30 or as the power of other electric devices. The electric energy generated from the power of the moving body 30 may be used to power the photoelectric conversion element 31. If the moving body 30 is an automobile, frictional energy generated by braking may be converted into electric energy and used to control the photoelectric conversion element 31. The moving body 30 may be, for example, an automobile, a ship, an aircraft, or a drone. The configuration of the body 32 of the moving body 30 is not particularly limited, but it is preferable that the body 32 be made of a high-strength material.

[0063] [Building materials] The building material of the present invention has the above-mentioned photoelectric conversion element. Fig. 3 is a perspective view showing an embodiment of a building material including the photoelectric conversion element of the present invention. The building material 40 may be the roof of a building. The building material 40 of this embodiment has the photoelectric conversion element 41 of the present invention, a protective member 42 that protects the photoelectric conversion element 41, a heat dissipation member 43, and exteriors 44a and 44b. The building material 40 of the present invention may have a heat dissipation member 43 having a higher thermal conductivity than the photoelectric conversion element 41. When used on a roof or the like, the temperature of the photoelectric conversion element 41 may increase due to sunlight, and the photoelectric conversion efficiency may decrease. The use of the heat dissipation member 43 can reduce the decrease in photoelectric conversion efficiency. Examples of the heat dissipation member 43 include metal, alloy, liquid metal, and liquid resin. Furthermore, the building material 40 of the present invention may have exteriors 44a and 44b. The exteriors 44a and 44b may emit different colors or may be the same. 44a and 44b may be made of the same material or different materials. Paint or a transparent substrate may be used as the exterior. A material with low light absorption and high heat insulation is preferable. EXAMPLES

[0064] The present invention will be described in more detail below using examples and comparative examples. The present invention is not limited to the following examples without departing from the gist of the present invention. In the following description of the examples, "parts" are by mass unless otherwise specified.

[0065] Preparation of particle 1 Process (1) In a nitrogen flow atmosphere, 5.46 parts of orthophthalonitrile and 45 parts of α-chloronaphthalene were put into a reaction vessel, and then heated to a temperature of 30°C and maintained at this temperature. Next, 3.75 parts of gallium trichloride were put in at this temperature (30°C). The water concentration of the mixed liquid at the time of putting in was 150 ppm. Then, the temperature was raised to 200°C. Next, under a nitrogen flow atmosphere, the reaction was carried out at a temperature of 200°C for 4.5 hours, and then cooled. When the temperature reached 150°C, the product was filtered. The obtained filtrate was dispersed and washed using N,N-dimethylformamide at a temperature of 140°C for 2 hours, and then filtered. The obtained filtrate was washed with methanol and then dried to obtain chlorogallium phthalocyanine particles with a yield of 71%.

[0066] Process (2) 4.65 parts of the chlorogallium phthalocyanine particles were dissolved in 139.5 parts of concentrated sulfuric acid at a temperature of 10° C., dropped into 620 parts of ice water under stirring to reprecipitate, and filtered under reduced pressure using a filter press. At this time, No. 5C (manufactured by Advantec Co., Ltd.) was used as the filter. The obtained wet cake (filtrate) was dispersed and washed with 2% ammonia water for 30 minutes, and then filtered using a filter press. Next, the obtained wet cake (filtrate) was dispersed and washed with ion-exchanged water, and then filtration using a filter press was repeated three times. Finally, freeze-drying was performed to obtain hydroxygallium phthalocyanine particles (hydrated hydroxygallium phthalocyanine particles) with a solid content of 23% by mass at a yield of 71%. The hydroxygallium phthalocyanine particles were dried in a Hyper Dry dryer (product name: HD-06R, frequency (oscillation frequency): 2455 MHz ± 15 MHz, manufactured by Japan Biocon) to obtain hydroxygallium phthalocyanine (OHGaPc) particles (crystals) with a moisture content of 1.0 mass% or less.

[0067] Process (3) Five parts of the hydroxygallium phthalocyanine particles were mixed with 5 parts of N-methylformamide solvent, and the mixture was dispersed for 6 hours using a sand mill (TSG-1 / 4G-4U, manufactured by Igarashi Machinery Manufacturing (now Imex), disk diameter 70 mm, number of disks 5) containing 5 parts of glass beads, filtered, and dried to obtain Particle 1 (specific gravity 1.6).

[0068] Preparation of resin solution 1 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 with stirring for 24 hours to obtain resin solution 1.

[0069] Preparation of resin solution 2 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 with stirring for 24 hours to obtain resin solution 2.

[0070] Preparation of resin solution 3 1.0 g of polymethyl methacrylate (PMMA, manufactured by Sigma-Aldrich Corporation, glass transition temperature 100° C.) was dissolved in 19 g of chlorobenzene with stirring for 24 hours to obtain resin solution 3.

[0071] Preparation of resin solution 4 Resin solution 4 was obtained by dissolving 1.0 g of poly(4-vinylpyridine) (glass transition temperature: 137° C.) in 19 g of 2-propanol with stirring for 24 hours.

[0072] Preparation of resin solution 5 1.0 g of poly(3-hexylthiophene-2,5-diyl) (P3HT, glass transition temperature 150° C. or more) was dissolved in 19 g of chlorobenzene with stirring for 24 hours to obtain resin solution 5.

[0073] Preparation of resin solution 6 Resin solution 6 was obtained by dissolving 1.0 g of poly[9,9-bis-(2-ethylhexyl)-9H-fluorene-2,7-diyl] (glass transition temperature: 45° C.) in 19 g of chlorobenzene with stirring for 24 hours.

[0074] Example 1 [Formation of Electron Transport Layer] A glass substrate with ITO was cleaned, and a 5-fold diluted tin oxide (2) colloidal solution (15% water dispersion, manufactured by Alfa Aesar) was spin-coated onto it, and then heated at 150°C for 30 minutes to form a thin-film electron transport layer with a thickness of 16 nm.

[0075] [Formation of photoelectric conversion layer] 1.1 g of lead iodide and 0.39 g of methylammonium iodide were dissolved in 0.36 g of N,N-dimethylformamide and 1.45 g of dimethylsulfoxide to prepare a photoelectric conversion layer coating solution. This coating solution was spin-coated on the electron transport layer to form a 500 nm-thick photoelectric conversion layer made of MAPbI3.

[0076] [Preparation of Composition, Formation of Charge Transport Layer] 0.1g of the particles 1 and 0.01g of the calixarene compound (a mixture of the calixarene compounds [C-1] to [C-4] of the above formula) were mixed with 10.6g of 2-propanol, and 11g of beads (zirconia beads, Treceram (registered trademark) zirconia beads, 0.3mm) were encapsulated in this mixture, and the mixture was dispersed with a paint shaker (manufactured by Toyo Seiki) for 3 hours to obtain a dispersion. Then, 0.2g of resin solution 1 was added to the dispersion (post-addition), and the dispersion was again dispersed with a paint shaker for 4 hours to prepare a charge transport layer coating liquid. This charge transport layer coating liquid was spin-coated on the photoelectric conversion layer to form a charge transport layer having a thickness of 180nm.

[0077] [Introduction of a second charge transport layer] 0.15 g of Spiro-OMeTAD as a 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 mixed. Furthermore, 58 μL of an acetonitrile solution obtained by dissolving 0.11 g of [tris(2-(1H-pyrazol-1-yl)-4-tert-butylpyridine)cobalt(3)tris(bis(trifluoromethylsulfonyl)imide)] in 0.3 g of acetonitrile was mixed to prepare a material solution for the second charge transport layer. This was applied by spin coating on 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 using CuKα radiation, the ratio of the peak intensity within the Bragg angle 2θ range of 7.6° to 8.6° to the total peak intensity within the range of 0.0° to 30.0° was 0.023.

[0078] [Formation of the first electrode] On the second charge transport layer, a layer having a thickness of 80 nm and an area of ​​0.09 cm 2 A gold electrode was formed by vacuum deposition to obtain a photoelectric conversion element.

[0079] Particle Size Analysis of Compositions The particle size of the pigment particles in the composition as the charge transport layer coating liquid was determined by measuring the Z-average particle size using the Zetasizer Nano-ZS (manufactured by MALVERN). The initial measurement was performed within 3 days after the composition was prepared. For the measurement after 3 months, the composition was stored in a sealed container after preparation and left to stand, and was shaken well to ensure that no sediment remained at the bottom of the container before the measurement.

[0080] [Photoelectric conversion efficiency evaluation] A power supply (KEITHLEY, Model 236) was connected between the electrodes of the photoelectric conversion element prepared in Example 1, and the intensity was 100 mW / cm 2The photoelectric conversion efficiency was measured by irradiating the device with a constant amount of light using a solar simulator (manufactured by Yamashita Denso Co., Ltd.) and measuring the generated current and voltage.

[0081] Comparative Example 1 A composition and a photoelectric conversion element were obtained in the same manner as in Example 1, except for the preparation method of the composition as the charge transport layer coating liquid. The composition was prepared by mixing 0.1 g of the particles 1 and the calixarene compound (a mixture of the above formulas [C-1] to [C-4]) with 0.00468 g (0.15 times the resin), 2.2 g of cyclohexanone, and 0.03 g of BX-1 resin, sealing beads (glass beads, 1 mm) in this mixture, and dispersing for 6 hours with a paint shaker (manufactured by Toyo Seiki Co., Ltd.) to obtain a dispersion. Then, 2.2 g of ethyl acetate was added to the dispersion to dilute it. It was confirmed that the ratio of the peak intensity within the range of the Bragg angle 2θ of 7.6° to 8.6° to the total peak intensity of 0.0° to 30.0° in the X-ray diffraction spectrum using CuKα radiation was 0.015.

[0082] (Examples 2 to 29, Comparative Examples 2 to 6) In preparing the composition as the charge transport layer coating liquid, the calixarene compound type, the ratio of the calixarene compound to the resin, the cyclic conjugated compound type, the resin type, the solvent type, the timing of adding the resin, the ratio of the pigment to the resin, and the presence or absence of the formation of a second charge transport layer in the formation of the element were changed, but the composition and the photoelectric conversion element were prepared and evaluated in the same manner as in Example 1. The results are shown in Table 2.

[0083] Calixarene compound types (dispersant types) [C-5] to [C-9] are shown below. [ka] [ka] [ka] [ka] [ka]

[0084] In addition, in Table 2 for Example 25 and Comparative Example 2, the timing of resin addition "first addition" means that in preparing the composition, resin solution 1 is added from the beginning together with particles 1, calixarene compound, and solvent, and dispersed for 7 hours using a paint shaker to obtain a charge transport layer coating liquid.

[0085] [Table 2]

[0086] The disclosure of this embodiment includes the following configuration. [Configuration 1] A composition comprising a pigment which is a cyclic conjugated compound in which a plurality of pyrrole rings are conjugatedly bonded, a dispersant, a resin, and a solvent, The dispersant is a calixarene compound represented by the following formula [A], A composition, wherein the mass of the dispersant in the composition is 0.20 times or more the mass of the resin in the composition. [ka] (In the formula [A], R 1 ~R 5 R 1 represents a hydrogen atom or an alkyl group, R 2 represents a substituted or unsubstituted alkylene group, R 3 ~R 5represents 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 at least one of them is a substituted or unsubstituted -Y-Ar group. -Y- in the -Y-Ar group represents -CH=N-, -CH=CH-, or -N=N-, and Ar represents a substituted or unsubstituted aromatic hydrocarbon group, or a substituted or unsubstituted heterocyclic group. n is an integer of 3 to 20. [Configuration 2] The composition according to embodiment 1, wherein n in the formula [A] is 4 or more and 8 or less. [Configuration 3] R in the above formula [A] 4 is independently a nitrophenylazo group or a dinitrophenylazo group for every n repeat units. [Configuration 4] 4. The composition according to any one of configurations 1 to 3, wherein the calixarene compound of the formula [A] has a molecular weight of 10,000 or less. [Configuration 5] The composition according to any one of configurations 1 to 4, wherein the calixarene compound of formula [A] has at least one selected from the group consisting of compounds represented by the following formulas [C-1], [C-2], [C-3] and [C-4]. [ka] [ka] [ka] [ka] [Configuration 6] 6. The composition according to any one of configurations 1 to 5, wherein the pigment which is a cyclic conjugated compound in which a plurality of pyrrole rings are conjugatedly bonded is a phthalocyanine compound. [Configuration 7] 7. The composition according to claim 6, wherein the central element of the phthalocyanine compound is non-metallic or at least one of gallium, aluminum, titanium, iron, and silicon. [Configuration 8] 8. The composition according to claim 7, wherein the phthalocyanine compound is a gallium phthalocyanine compound. [Configuration 9] 9. The composition according to claim 8, wherein the gallium phthalocyanine compound is hydroxygallium phthalocyanine. [Configuration 10] 10. The composition according to any one of claims 1 to 9, wherein the resin is a resin having a Lewis basic functional group. [Configuration 11] 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 a hydroxy group, a carbonyl group, an ether bond, an ester bond, a pyridyl group, and a thienyl group. [Configuration 12] 12. The composition according to any one of claims 1 to 11, wherein the resin has a glass transition temperature (Tg) of 95°C or lower. [Configuration 13] 13. The composition according to claim 11 or 12, wherein the resin is a polyvinyl acetal resin or a polyvinyl butyral resin. [Configuration 14] 14. The composition according to any one of claims 1 to 13, wherein the solvent has a vapor pressure (20°C) of 0.06 kPa or more. [Configuration 15] 15. The composition according to any one of configurations 1 to 14, wherein the mass of the dispersant in the composition is 0.01 to 0.50 times the mass of the pigment in the composition. [Configuration 16] 16. The composition according to claim 1, wherein the mass of the pigment in the composition is 5 to 20 times the mass of the resin in the composition. [Method 1] A method for preparing a composition containing a pigment that is a cyclic conjugated compound in which a plurality of pyrrole rings are conjugatedly bonded, a dispersant, a resin, and a solvent, the method comprising the steps of: The dispersant is a calixarene compound represented by the following formula [A], The composition has a mass of the dispersant in the composition that is 0.20 times or more the mass of the resin in the composition, A method for preparing a composition, comprising dispersing said pigment and said dispersant in said solvent to obtain a dispersion, and then adding said resin to said dispersion and dispersing it again. [ka] (In the above formula [A], R 1 ~R 5 R 1 represents a hydrogen atom or an alkyl group, R 2 represents a substituted or unsubstituted alkylene group, R 3 ~R 5 represents hydrogen, 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 ring, and at least one is a substituted or unsubstituted -Y-Ar group. -Y- in the -Y-Ar group represents -CH=N-, -CH=CH-, or -N=N-, and Ar is a substituted or unsubstituted aromatic hydrocarbon group, or a substituted or unsubstituted heterocyclic group. n is an integer of 3 to 20. [Configuration 17] The particle size of the pigment is 1.0×10 1 nm or more 5.0×10 2 The composition according to any one of configurations 1 to 15, wherein the thickness of the composition is equal to or less than nm. [Configuration 18] A photoelectric conversion element having a first electrode, a photoelectric conversion layer containing a crystal of a perovskite structure, a charge transport layer, and a second electrode, characterized in that the photoelectric conversion element has a charge transport layer formed using the composition according to any one of configurations 1 to 15 or 17 between the photoelectric conversion layer and the first electrode. [Configuration 19] 19. The photoelectric conversion element according to configuration 18, further comprising a second charge transport layer between the first electrode and the charge transport layer. [Explanation of symbols]

[0087] 1 Photoelectric conversion element 2. Board 3 Second electrode 4 Electron transport layer 5 Photoelectric conversion layer 6 Charge transport layer 7 First electrode 30 Mobile 31, 41 Photoelectric conversion element 32 Aircraft 40 Building materials 42 Protective materials 43 Heat dissipation materials 44a, 44b Exterior

Claims

1. A composition comprising a pigment which is a cyclic conjugated compound in which a plurality of pyrrole rings are conjugatedly bonded, a dispersant, a resin, and a solvent, The dispersant is a calixarene compound represented by the following formula [A], A composition, wherein the mass of the dispersant in the composition is 0.20 times or more the mass of the resin in the composition. 【Chemistry 1】 (In the formula [A], R １ ~R ５ R １ represents a hydrogen atom or an alkyl group; R ２ represents a substituted or unsubstituted alkylene group; R ３ ~R ５ 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 at least one is a substituted or unsubstituted -Y-Ar group. -Y- in the -Y-Ar group represents -CH=N-, -CH=CH-, or -N=N-, and Ar is a substituted or unsubstituted aromatic hydrocarbon group, or a substituted or unsubstituted heterocyclic group. n is an integer of 3 or more and 20 or less.

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

3. R in the formula [A] ４ The composition of claim 1 , wherein every n repeat units each independently represents a nitrophenylazo group or a dinitrophenylazo group.

4. The composition according to claim 1, wherein the molecular weight of the calixarene compound of formula [A] is 10,000 or less.

5. The composition according to claim 1, wherein the calixarene compound of formula [A] has at least one selected from the group consisting of compounds represented by the following formulas [C-1], [C-2], [C-3] and [C-4]. 【Chemistry 2】 【Chemistry 3】 【Chemistry 4】 【Chemistry 5】

6. The composition according to claim 1 , wherein the pigment which is a cyclic conjugated compound in which a plurality of pyrrole rings are conjugatedly bonded is a phthalocyanine compound.

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

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

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

10. The composition of claim 1 , wherein the resin is a resin having Lewis basic functional groups.

11. The composition according to claim 1 , wherein the resin has at least one functional group selected from the group consisting of a hydroxy group, a carbonyl group, an ether bond, an ester bond, a pyridyl group, and a thienyl group.

12. 2. The composition of claim 1, wherein the resin has a glass transition temperature (Tg) of 95°C or less.

13. 2. The composition according to claim 1, wherein the resin is a polyvinyl acetal resin or a polyvinyl butyral resin.

14. The composition according to claim 1 , wherein the vapor pressure (20° C.) of the solvent is 0.06 kPa or more.

15. The composition according to claim 1 , wherein the mass of the dispersant in the composition is 0.01 times or more and 0.50 times or less the mass of the pigment in the composition.

16. The composition according to claim 1 , wherein the mass of the pigment in the composition is 5 to 20 times the mass of the resin in the composition.

17. A method for preparing a composition containing a pigment that is a cyclic conjugated compound in which a plurality of pyrrole rings are conjugatedly bonded, a dispersant, a resin, and a solvent, the method comprising the steps of: The dispersant is a calixarene compound represented by the following formula [A], The composition has a mass of the dispersant in the composition that is 0.20 times or more the mass of the resin in the composition, A method for preparing a composition, comprising dispersing said pigment and said dispersant in said solvent to obtain a dispersion, and then adding said resin to said dispersion and dispersing it again. 【Chemistry 6】 (In the above formula [A], R １ ~R ５ R １ represents a hydrogen atom or an alkyl group; R ２ represents a substituted or unsubstituted alkylene group; R ３ ~R ５ 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 ring, and at least one is a substituted or unsubstituted -Y-Ar group. -Y- in the -Y-Ar group represents -CH=N-, -CH=CH-, or -N=N-, and Ar is a substituted or unsubstituted aromatic hydrocarbon group, or a substituted or unsubstituted heterocyclic group. n is an integer of 3 to 20.

18. The particle size of the pigment is 1.0×10 １ nm or more 5.0×10 ２ The composition of claim 1, wherein the particle size is less than or equal to nm.

19. A photoelectric conversion element having a first electrode, a photoelectric conversion layer containing a crystal of a perovskite structure, a charge transport layer, and a second electrode, characterized in that the photoelectric conversion element has a charge transport layer formed using the composition according to any one of claims 1 to 16 or 18 between the photoelectric conversion layer and the first electrode.

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

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