Aromatic diimide derivative and perovskite solar cell employing the same

Abstract

To provide: a compound that can be used in an n-type buffer layer of a perovskite solar cell; and a favorable perovskite solar cell employing the compound.SOLUTION: The invention provides an aromatic diimide derivative represented by general formula (I) in the figure. (In general formula (I): A is a phosphonic acid group, a phosphoric acid group, a sulfonic acid group, a sulfuric acid group, or a group corresponding to a salt of them; R is a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, or a substituted alkyl group; a is an integer from 1 to 6; and b is 0 or 1.)SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a novel compound used as a functional material for improving the performance of perovskite solar cells, and a solar cell using the same. [Background technology]

[0002] Solar cells that can efficiently convert sunlight into electricity have been attracting attention from the perspective of energy and environmental issues. Most solar cells in practical use use silicon, but these solar cells are expensive to manufacture and have not yet been widely adopted in ordinary households. In addition, the installation locations may be limited due to issues such as load resistance. In order to make renewable energy the main power source in the future, it is essential to further expand the introduction of solar power generation facilities, and research is being conducted on new types of solar cells to replace silicon solar cells. Organic solar cells have the advantages of fewer resource constraints, relatively low manufacturing costs, and are lightweight and flexible, and their widespread use is expected. However, they are inferior to silicon solar cells in terms of energy conversion efficiency and durability, and there are still challenges to be overcome before they can be put into practical use.

[0003] Perovskite solar cells, which are one type of organic solar cell, saw a rapid improvement in energy conversion efficiency when a solution-type cell was reported in 2009 (Non-Patent Document 1), and then a solid-type cell was reported in 2012 (Non-Patent Document 2). The basic structure of a perovskite solar cell is usually a transparent electrode on which a light absorbing layer (perovskite layer) is sandwiched between an n-type buffer layer, which is an n-type semiconductor, and a p-type buffer layer, which is a p-type semiconductor, as shown in Figure 1. The n-type buffer A dense titania film made of titanium oxide is generally used as the layer, and an organic semiconductor hole transport material is often used as the p-type buffer layer.

[0004] Dense titania films are generally used as electron transport materials in perovskite solar cells, which have high energy conversion efficiency, but these compounds require high-temperature processing during film formation, which poses a challenge when fabricating flexible solar cells. Therefore, there is a demand for the development of electron transport materials that do not require high-temperature processing.

[0005] As such an electron transport material, for example, Non-Patent Document 3 reports an aromatic imide derivative capable of forming a self-assembled film represented by the following chemical formula. This compound is called "Compound 1." Since this compound has a carboxyl group in the bonding group, a 6-hour immersion process is required for film formation in order to fabricate a solar cell with high energy conversion efficiency, and there remain issues in applying it to roll-to-roll mass production when it is put to practical use. [ka] [Prior art documents] [Non-patent literature]

[0006] [Non-Patent Document 1] J. Am. Chem. Soc. (2009) Vol.131, p.6050-6051 [Non-Patent Document 2] Science (2012) Vol.388, p.643-647 [Non-Patent Document 3] Chem. Commun. (2019) Vol.55, p13239-13242

[0007] The present inventors have developed an electron transport material that does not require high-temperature treatment or a long film formation process. Compound 2, which has a phosphonic acid group in the coupling group, was synthesized. Although compound 2 was able to form an n-type buffer layer on the conductive layer in a short time, a perovskite layer could not be formed on the n-type buffer layer, and a solar cell could not be fabricated. Therefore, it was found that further structural modification was necessary to form a perovskite layer. In this context, the introduction of an electron transport material capable of forming a self-assembled film would be useful for practical application of the advantages of perovskite solar cells, as it would allow the introduction of an n-type buffer layer without the need for high-temperature processes. However, there have been few reports of compounds that can achieve this, and the development of superior materials is required. [ka] Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention has been made in view of the above-mentioned situation in the conventional technology, and an object of the present invention is to provide a compound that can be used in the n-type buffer layer of a perovskite solar cell, and further to provide a good perovskite solar cell using this compound. [Means for solving the problem]

[0009] The present inventors have conducted extensive research to solve the above problems, and as a result have found that the above problems can be solved by introducing a novel aromatic diimide derivative into the n-type buffer layer of a perovskite solar cell, thereby completing the present invention.

[0010] That is, the present invention relates to the following [1] to

[11] . [1] An aromatic diimide derivative represented by general formula (I). [ka] (In the general formula (I), A is a phosphonic acid group, a phosphoric acid group, a sulfonic acid group, or a sulfate group, or a group corresponding to a salt thereof; R is a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, or a substituted alkyl group; a is an integer of 1 to 6; and b is 0 or 1.) [2] The substituent of the substituted aryl group or substituted heteroaryl group in the general formula (I) is an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an amino group, an alkoxy group, a haloalkoxy group, an aryloxy group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an acyloxy group, an acylamino group, an alkoxycarbonylamino group, an aryloxycarbonylamino group, a sulfonylamino group, a sulfamoyl group, a carbamoyl group, a substituted or unsubstituted aryl group, an alkylthio group, an arylthio group, a sulfonyl group, a halogen atom, a cyano group, and a heterocyclic group; The aromatic diimide derivative according to [1], wherein the substituent of the substituted alkyl group in the general formula (I) is selected from the group consisting of an amino group, an alkoxy group, a haloalkoxy group, an aryloxy group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an acyloxy group, an acylamino group, an alkoxycarbonylamino group, an aryloxycarbonylamino group, a sulfonylamino group, a sulfamoyl group, a carbamoyl group, an alkylthio group, an arylthio group, a sulfonyl group, a halogen atom, a cyano group, and a heterocyclic group. [3] The aromatic diimide derivative according to [1] or [2], wherein R in the general formula (I) is an unsubstituted aryl group or an unsubstituted heteroaryl group. [4] The aromatic diimide derivative according to any one of [1] to [3], wherein b in the general formula (I) is 0. [5] The aromatic diimide derivative according to any one of [1] to [4], wherein A in the general formula (I) is a group corresponding to a phosphonic acid group or a salt thereof. [6] The aromatic diimide derivative according to any one of [1] to [5], wherein R in the general formula (I) is a substituted or unsubstituted aryl group, or a substituted or unsubstituted heteroaryl group, the heteroaryl group containing, as a ring atom other than carbon atoms, at least one heteroatom selected from a nitrogen atom and a sulfur atom. [7] The aromatic diimide derivative according to any one of [1] to [6], which is represented by general formulas (II) to (XI): [ka] [ka] [8] A photoelectric conversion element comprising the aromatic diimide derivative according to any one of [1] to [7]. [9] A perovskite solar cell comprising the photoelectric conversion element according to [8].

[10] A photodiode comprising the photoelectric conversion element according to [8].

[11] An optical sensor comprising the photoelectric conversion element according to [8]. Effect of the Invention

[0011] According to the aromatic diimide derivative of the present invention, an n-type buffer layer can be introduced into a perovskite solar cell by solution processing without high-temperature treatment, and good conversion efficiency can be achieved. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a cross-sectional view illustrating a schematic example of a perovskite solar cell of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Each embodiment of the present invention will be described. Note that each embodiment described below does not limit the invention according to the claims, and all of the elements and combinations thereof described in each embodiment are not necessarily essential to the solution of the present invention.

[0014] In the present invention, the description of "XX or more and YY or less" or "XX to YY" representing a numerical range means a numerical range including the lower and upper limits which are the endpoints, unless otherwise specified. When a numerical range is described in stages, the upper and lower limits of each numerical range can be arbitrarily combined.

[0015] [Aromatic diimide derivative] An aromatic diimide derivative according to one embodiment of the present invention (hereinafter, also simply referred to as an "aromatic diimide derivative") is an aromatic diimide derivative represented by general formula (I) and can be formed into various compounds.

[0016] [ka] (In the general formula (I), A is a phosphonic acid group, a phosphoric acid group, a sulfonic acid group, or a sulfate group, or a group corresponding to a salt thereof; R is a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, or a substituted alkyl group; a is an integer of 1 to 6; and b is 0 or 1.)

[0017] Compound 2 is an aromatic diimide derivative in which R in general formula (I) is an unsubstituted alkyl group. When compound 2 was used for the n-type buffer layer, as described above, a perovskite layer could not be formed on the n-type buffer layer, and a solar cell could not be produced.

[0018] On the other hand, the present inventors have found that when the aromatic diimide derivative of the present invention, in which R in general formula (I) is a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, or a substituted alkyl group, is used for an n-type buffer layer, a perovskite layer can be formed on the n-type buffer layer, and a solar cell can be produced.

[0019] The aromatic diimide derivative is preferably a compound represented by general formula (I').

[0020] [ka] (In general formula (I'), R is a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, or a substituted alkyl group; and a is an integer of 1 to 6.)

[0021] In general formula (I) and general formula (I'), a is preferably an integer of 2 to 4, and more preferably 2. Moreover, the aromatic diimide derivative is preferably a compound represented by general formula (I').

[0022] At least one type of aromatic diimide derivative can be introduced into the n-type buffer layer, and multiple types can also be introduced.

[0023] In one embodiment, R in general formula (I) and general formula (I') is a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, or a substituted alkyl group. Here, the term "aryl" means an aryl group having 6 to 14 carbon atoms (C6-14 aryl). The aryl group is not particularly limited, but examples thereof include phenyl, naphthyl, or ortho-fused bicyclic groups having 8 to 10 ring atoms, at least one of which is an aromatic ring (e.g., indenyl, etc.).

[0024] In addition, the term "heteroaryl" means a 5- to 7-membered aromatic heterocyclic (monocyclic) group containing, as ring atoms other than carbon atoms, 1 to 4 heteroatoms of 1 to 3 kinds selected from a nitrogen atom, a sulfur atom, and an oxygen atom, and may be, for example, a group derived from pyridine, pyrazine, pyrimidine, pyridazine, triazine, pyrrole, thiophene, furan, imidazole, pyrazole, thiazole, isothiazole, oxazole, isoxazole, etc. Specific examples thereof include furyl, thienyl, pyrrolyl, thiazolyl, pyrazolyl, oxazolyl, isoxazolyl, isothiazolyl, imidazolyl, 1,2,4-oxadiazolyl, 1,3,4-oxadiazolyl, 1,2,3-triazolyl, 1,2,4-triazolyl, 1,2,4-thiadiazolyl, 1,3,4-thiadiazolyl, tetrazolyl, pyridyl, pyridinium, pyrimidinyl, pyrimidinium, pyrazinyl, pyrazinium, pyridazinyl, pyridazinium, triazinyl, triazinium, azepinyl, and diazepinyl. In addition, "heteroaryl" also includes groups derived from aromatic heterocycles (bicyclic or higher) formed by condensing a 5- to 7-membered aromatic heterocycle containing, as ring atoms other than carbon atoms, 1 to 4 heteroatoms of 1 to 3 kinds selected from nitrogen atoms, sulfur atoms, and oxygen atoms to a benzene ring or the above-mentioned aromatic heterocycle (monocyclic) group, such as indolyl, isoindolyl, benzo[b]furyl, benzo[b]thienyl, benzimidazolyl, benzoxazolyl, benzisoxazolyl, benzothiazolyl, benzisothiazolyl, quinolyl, isoquinolyl, etc.

[0025] In the general formula (I) and the general formula (I'), R is preferably a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group, and the heteroaryl group preferably has at least one ring atom selected from a nitrogen atom and a sulfur atom in addition to carbon atoms. It preferably contains one heteroatom.

[0026] In other embodiments, R may have a substituent. When R is a substituted aryl group or a heteroaryl group, the substituent is preferably an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an amino group, an alkoxy group, a haloalkoxy group, an aryloxy group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an acyloxy group, an acylamino group, an alkoxycarbonylamino group, an aryloxycarbonylamino group, a sulfonylamino group, a sulfamoyl group, a carbamoyl group, an alkylthio group, an arylthio group, a sulfonyl group, a halogen atom, a cyano group, and a heterocyclic group. When R is a substituted aryl group or a heteroaryl group, the substituent is more preferably an alkyl group, an alkenyl group, an alkynyl group, an amino group, an alkoxy group, and an alkylthio group.

[0027] When R is a substituted alkyl group, preferred examples of the substituent include an amino group, an alkoxy group, a haloalkoxy group, an aryloxy group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an acyloxy group, an acylamino group, an alkoxycarbonylamino group, an aryloxycarbonylamino group, a sulfonylamino group, a sulfamoyl group, a carbamoyl group, an alkylthio group, an arylthio group, a sulfonyl group, a halogen atom, a cyano group, and a heterocyclic group. More preferred examples of the substituent when R is a substituted alkyl group include an amino group, an alkoxy group, and an alkylthio group.

[0028] The term "alkyl" generally means a straight or branched alkyl having 1 to 15 carbon atoms (C1-15 alkyl), and examples thereof include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl, neopentyl, hexyl, heptyl, octyl, nonyl, decyl, etc. Preferred are C1-6 alkyls such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, or pentyl, more preferred are methyl or ethyl, and most preferred is methyl.

[0029] Furthermore, examples of "alkenyl" include linear or branched alkenyl having 2 to 10 carbon atoms (C2-10 alkenyl), specifically, vinyl, allyl, 1-propenyl, isopropenyl, methacryl, butenyl, crotyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, etc.

[0030] Furthermore, examples of "alkynyl" include linear or branched alkynyl having 2 to 10 carbon atoms (C2-10 alkynyl). Specific examples include ethynyl, propargyl, butynyl, pentynyl, hexynyl, heptynyl, octynyl, nonynyl, decynyl, and the like.

[0031] Furthermore, "alkoxy" includes, for example, straight or branched alkoxy having 1 to 6 carbon atoms (C1-6 alkoxy). Specifically, it is methoxy or ethoxy. Furthermore, "haloalkoxy" includes the above C1-6 alkoxy substituted with one or more halogen atoms.

[0032] The number of carbon atoms in the substituent is preferably 1 to 6, and more preferably 1 to 3. The substitution position of the substituent in R is not particularly limited.

[0033] Examples of A in the general formula (I) include a phosphonic acid group, a phosphoric acid group, a sulfonic acid group, a sulfate group, or a group equivalent to a salt thereof.

[0034] Specific examples of the aromatic diimide derivative include compounds represented by the following general formulas (II) to (XV).

[0035] [ka]

[0036] [ka]

[0037] [ka]

[0038] In the case of compound 4 of the present invention described later, for example, the aromatic diimide derivative can be produced by reacting naphthalene-1,4,5,8-tetracarboxylic dianhydride with diethyl 2-aminoethylphosphonate, and further reacting with 4-methoxyaniline to synthesize a skeleton such as compound 3 synthesized in Example 1 described later, and further treating the skeleton with bromotrimethylsilane. Other aromatic diimide derivatives can also be produced based on the above production method and ordinary organic chemical synthesis techniques.

[0039] [Photoelectric conversion element] The aromatic diimide derivative can be used as a compound to be introduced into the n-type buffer layer of a photoelectric conversion element. The photoelectric conversion element according to one embodiment of the present invention (hereinafter, also simply referred to as "photoelectric conversion element") may have the structure of a normal photoelectric conversion element, except that an aromatic diimide derivative is introduced into the n-type buffer layer. Specifically, for example, as shown in FIG. 1, a photoelectric conversion element having a conductive layer on a conductive support, an n-type buffer layer on the conductive layer, a first electrode having a light absorbing layer containing a perovskite compound on the n-type buffer layer, and a second electrode (counter electrode to the p-type buffer layer) facing the first electrode, in which the aromatic diimide derivative is introduced into the n-type buffer layer by contacting the conductive layer with a solution containing the aromatic diimide derivative, is exemplified. Examples of photoelectric conversion elements include perovskite solar cells, photodiodes, and optical sensors. can be used.

[0040] The photoelectric conversion element can be manufactured by a normal method for manufacturing a photoelectric conversion element, except that an aromatic diimide derivative is introduced into the n-type buffer layer. To introduce an aromatic diimide derivative into the surface of the conductive layer, a liquid containing the aromatic diimide derivative is used. This liquid may be the liquid aromatic diimide derivative itself, or may be a solution or suspension (dispersion) containing the aromatic diimide derivative. The solvent or dispersion medium is not particularly limited as long as it can dissolve or disperse the aromatic diimide derivative, and for example, dimethyl sulfoxide can be preferably used. The concentration of the aromatic diimide derivative in the liquid is not particularly limited, but is preferably, for example, 0.001 to 500 mM, and more preferably 0.01 to 50 mM.

[0041] The method of contacting the prepared liquid with the surface of the conductive layer is not particularly limited, and examples thereof include a method of coating the liquid on the surface of the conductive layer. The coating method is not particularly limited, and examples thereof include spin coating, spray coating, screen printing, and immersion. The coating temperature is preferably 0 to 50°C.

[0042] After application, it is preferable to dry the liquid. The drying conditions are not particularly limited. The drying temperature is, for example, preferably 20 to 200° C., more preferably 60 to 150° C. The drying time is, for example, preferably 1 minute to 5 hours, more preferably 3 minutes to 1 hour.

[0043] The amount of the aromatic diimide derivative of the present invention present on the surface of the conductive layer can be appropriately adjusted depending on the type of aromatic diimide derivative, the desired performance, etc., and is not particularly limited. For example, 2 ~100mg / m 2 is preferred, and 0.001 mg / m 2 ~10mg / m 2 is more preferred.

[0044] The n-type buffer layer may contain materials other than the aromatic diimide derivative of the present invention.

[0045] [Perovskite solar cells] The aromatic diimide derivative can be used, for example, as a compound to be introduced into the n-type buffer layer of a perovskite solar cell. A perovskite solar cell according to one embodiment of the present invention (hereinafter, also simply referred to as a "perovskite solar cell") may have the structure of a normal perovskite solar cell, except that an aromatic diimide derivative is introduced into the n-type buffer layer. That is, the conductive support, conductive layer, perovskite layer (light absorbing layer), p-type buffer layer (hole transport layer), and counter electrode can be well known. The perovskite solar cell can be manufactured by a normal manufacturing method for a perovskite solar cell, except that an aromatic diimide derivative is introduced into the n-type buffer layer.

[0046] As the conductive support, glass or plastic having a conductive layer on the surface can be suitably used. As the conductive layer, metals such as gold, platinum, silver, copper, and indium, conductive carbon, indium-tin composite compounds, and tin oxide doped with fluorine can be used. Using these conductive materials, a conductive layer can be formed on the support surface by a conventional method. In addition, when the conductive support is used as a light-receiving surface, it is preferable that the conductive support is transparent.

[0047] The material constituting the p-type buffer layer is not particularly limited, and examples thereof include p-type small molecule organic semiconductors, p-type conductive polymers, p-type inorganic materials, etc. Specific examples thereof include 2,2',7,7'-tetrakis(N,N-di-p-methoxyphenylamino)-9,9'-spirobifluorene (Spiro-OMeTAD), poly(3-hexylthiophene-2,5-diyl) (P3HT), poly(3,4-ethylenedioxythiophene) (PEDOT), poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA ), copper iodide, copper thiocyanate, etc. The p-type buffer layer can be formed by a known film formation method depending on the material.

[0048] The perovskite layer may contain at least one perovskite compound represented by the composition formula ABX3, and may contain two or more perovskite compounds. The light absorbing layer may be a single layer or a laminate of two or more layers. In the case of a laminate structure of two or more layers, an intermediate layer such as a hole transport material may be laminated between each layer. A is a monovalent cation, such as a methylammonium cation, a formamidinium cation, or an alkali metal cation. B is a divalent cation, such as a lead cation, a germanium cation, or a tin cation. X is a monovalent anion such as a halogen anion. The perovskite layer can be formed by a solution coating method, a co-evaporation method, or the like.

[0049] The counter electrode is not particularly limited as long as it has electrical conductivity, and examples thereof include gold, silver, platinum, palladium, rhodium, tungsten, molybdenum, tantalum, titanium, niobium, etc. The counter electrode can be formed by a conventional method using these conductive materials.

[0050] Solvents or dispersion media used in the manufacturing method of the photoelectric conversion element and the solar cell include alcohol solvents such as methanol, ethanol, n-propanol, isopropanol, n-butanol, and tert-butanol, organic solvents such as chloroform, acetone, acetonitrile, tetrahydrofuran, dimethyl sulfoxide, N,N-dimethylformamide, benzene, toluene, xylene, chlorobenzene, and dichlorobenzene, and mixed solvents thereof, preferably dimethyl sulfoxide. EXAMPLES

[0051] The present invention will be described in more detail below using examples, but the present invention is not limited to these examples.

[0052] <Example 1> DMF (50 mL) was added to naphthalene-1,4,5,8-tetracarboxylic dianhydride (1.00 g) and heated to 100°C. Diethyl 2-aminoethylphosphonate (0.68 g) was added to this mixture and heated to reflux. Furthermore, 4-methoxyaniline (0.46 g) was added and heated to reflux. The solvent was distilled off under reduced pressure, and the residue was purified by column chromatography to obtain 1.09 g of product. This product is called "Compound 3".

[0053] [ka]

[0054] Compound 3 (1.00 g) and bromotrimethylsilane (4.28 g) were dissolved in dichloromethane (300 mL) and stirred at room temperature. Methanol was added to the reaction mixture, and the solvent was distilled off under reduced pressure. Methanol and water were added to the residue and stirred. The resulting solid was filtered to obtain 0.86 g of product. 1 Analysis by H-NMR revealed that the product was of the following formula: This product is designated "Compound 4".

[0055] [ka] 1 H-NMR(400MHz,DMSO-d6):δ8.71-8.66 (4H, m), 7.34 (2H, d, 8.9), 7.09 (2H, d, 8.9), 4.32-4.25 (2H, m), 3.39 (3H, s), 2.05-1.97 (2H, m)

[0056] <Example 2> DMF (50 mL) was added to naphthalene-1,4,5,8-tetracarboxylic dianhydride (1.00 g) and heated to 100°C. Diethyl 2-aminoethylphosphonate (0.68 g) was added to this mixture and heated to reflux. Furthermore, 3-methoxyaniline (0.46 g) was added and heated to reflux. The solvent was distilled off under reduced pressure, and the residue was purified by column chromatography to obtain 0.84 g of product. This product is called "Compound 5".

[0057] [ka]

[0058] Compound 5 (0.80 g) and bromotrimethylsilane (3.42 g) were dissolved in dichloromethane (250 mL) and stirred at room temperature. Methanol was added to the reaction mixture, and the solvent was distilled off under reduced pressure. Methanol and water were added to the residue and stirred. The resulting solid was filtered to obtain 0.76 g of product. 1 H-NMR analysis revealed that the product was of the following formula: This product is designated "Compound 6".

[0059] [ka] 1 H-NMR(400MHz,DMSO-d6):δ 8.71-8.66 (4H, m), 7.48-7.43 (1H, m), 7.08-7.06 (2H, m), 7.01 (1H, dd, 7.9, 1.4), 4.31-4.25 (2H, m), 3.78 (3H, s), 2.06-1.97 (2H, m)

[0060] <Example 3> DMF (50 mL) was added to naphthalene-1,4,5,8-tetracarboxylic dianhydride (1.00 g) and heated to 100°C. Diethyl 2-aminoethylphosphonate (0.68 g) was added to this mixture and heated to reflux. Furthermore, 3,4-dimethoxyaniline (0.57 g) was added and heated to reflux. The solvent was distilled off under reduced pressure, and the residue was purified by column chromatography to obtain 0.82 g of product. This product is called "Compound 7".

[0061] [ka]

[0062] Compound 7 (0.75 g) and bromotrimethylsilane (3.04 g) were dissolved in dichloromethane (150 mL) and stirred at room temperature. Methanol was added to the reaction mixture, and the solvent was distilled off under reduced pressure. Methanol and water were added to the residue and stirred. The resulting solid was filtered to obtain 0.70 g of product. 1 H-NMR analysis revealed that the product was of the following formula: This product is designated "Compound 8". [ka] 1 H-NMR(400MHz,DMSO-d6):δ 8.69-8.64 (4H, m), 7.10-7.07 (2H, m), 6.95 (2H, dd, 8.5, 2.3), 4.31-4.25 (2H, m), 3.84 (3H, s), 3.71 (3H, s), 2.06-1.97 (2H, m)

[0063] <Example 4> DMF (50 mL) was added to naphthalene-1,4,5,8-tetracarboxylic dianhydride (1.00 g) and heated to 100°C. Diethyl 2-aminoethylphosphonate (0.68 g) was added to this mixture and heated to reflux. Furthermore, 3,5-dimethoxyaniline (0.68 g) was added and heated to reflux. The solvent was distilled off under reduced pressure, and the residue was purified by column chromatography to obtain 1.00 g of product. This product is called "Compound 9."

[0064] [ka]

[0065] Compound 9 (1.00 g) and bromotrimethylsilane (4.05 g) were dissolved in dichloromethane (300 mL) and stirred at room temperature. Methanol was added to the reaction mixture, and the solvent was distilled off under reduced pressure. Methanol and water were added to the residue and stirred. The resulting solid was filtered to obtain 0.91 g of product. 1 H-NMR analysis revealed that the product was of the following formula: This product is designated "Compound 10".

[0066] [ka] 1 H-NMR(400MHz,DMSO-d6):δ 8.72-8.67 (4H, m), 6.66-6.63 (3H, m), 4.31-4.25 (2H, m), 3.77 (6H, s), 2.06-1.97 (2H, m)

[0067] <Example 5> DMF (50 mL) was added to naphthalene-1,4,5,8-tetracarboxylic dianhydride (1.00 g) and heated to 100°C. 2-aminoethylphosphonic acid diethyl ester (0.68 g) was added to this mixture and heated to reflux. Furthermore, 3,4,5-trimethoxyaniline (0.68 g) was added and heated to reflux. The solvent was distilled off under reduced pressure, and the residue was purified by column chromatography to obtain 0.74 g of product. This product is called "Compound 11".

[0068] [ka]

[0069] Compound 11 (0.70 g) and bromotrimethylsilane (2.69 g) were dissolved in dichloromethane (150 mL) and stirred at room temperature. Methanol was added to the reaction mixture, and the solvent was distilled off under reduced pressure. Methanol and water were added to the residue and stirred. The resulting solid was filtered to obtain 0.65 g of product. 1 H-NMR analysis revealed that the product was represented by the following formula: This product was named "Compound 12."

[0070] [ka] 1 H-NMR(400MHz,DMSO-d6):δ 8.69-8.64 (4H, m), 6.83 (2H, s), 4.31-4.25 (2H, m), 3.76 (3H, s), 3.74 (6H, s), 2.06-1.97 (2H, m)

[0071] <Example 6> DMF (45 mL) was added to naphthalene-1,4,5,8-tetracarboxylic dianhydride (0.86 g) and heated to 100°C. 2-aminoethyl diethyl phosphonate (0.58 g) was added to this mixture and heated to reflux. Furthermore, 4'-aminobenzo-15-crown-5-ether (0.91 g) was added and heated to reflux. The solvent was distilled off under reduced pressure, and the residue was purified by column chromatography to obtain 1.19 g of product. This product is called "Compound 13".

[0072] [ka]

[0073] Compound 13 (1.10 g) and bromotrimethylsilane (3.63 g) were dissolved in dichloromethane (200 mL) and stirred at room temperature. Methanol was added to the reaction mixture, and the solvent was distilled off under reduced pressure. Methanol and water were added to the residue and stirred. The resulting solid was filtered to obtain 1.02 g of product. 1 H-NMR analysis revealed that the product was of the following formula: This product is designated "Compound 14".

[0074] [ka] 1 H-NMR(400MHz,DMSO-d6):δ 8.71-8.64 (4H, m), 7.09-7.06 (2H, m), 6.95 (1H, dd, 8.4, 2.3), 4.31-4.25 (2H, m), 4.14-4.13 (2H, m), 4.01-3.99 (2H, m), 3.84-3.81(2H, m), 3.78-3.76 (2H, m), 3.67-3.64 (8H, m), 2.06-1.97 (2H, m)

[0075] <Example 7> DMF (50 mL) was added to naphthalene-1,4,5,8-tetracarboxylic dianhydride (1.00 g) and heated to 100°C. Diethyl 2-aminoethylphosphonate (0.68 g) was added to this mixture and heated to reflux. Furthermore, 4-methylthioaniline (0.52 g) was added and heated to reflux. The solvent was distilled off under reduced pressure, and the residue was purified by column chromatography to obtain 0.99 g of product. This product is called "Compound 15".

[0076] [ka]

[0077] Compound 15 (0.95 g) and bromotrimethylsilane (3.95 g) were dissolved in dichloromethane (300 mL) and stirred at room temperature. Methanol was added to the reaction mixture, and the solvent was distilled off under reduced pressure. Methanol and water were added to the residue and stirred. The resulting solid was filtered to obtain 0.88 g of product. 1 H-NMR analysis revealed that the product was of the following formula: This product is designated "Compound 16".

[0078] [ka] 1 H-NMR(400MHz,DMSO-d6):δ 8.71-8.66 (4H, m), 7.42 (2H, d, 8.6), 7.37 (2H, d , 8.6), 4.31-4.25 (2H, m), 2.56 (3H, s), 2.06-1.97 (2H, m)

[0079] <Example 8> DMF (50 mL) was added to naphthalene-1,4,5,8-tetracarboxylic dianhydride (1.00 g) and heated to 100°C. Diethyl 2-aminoethylphosphonate (0.68 g) was added to this mixture and heated to reflux. Furthermore, 3-methylthioaniline (0.52 g) was added and heated to reflux. The solvent was distilled off under reduced pressure, and the residue was purified by column chromatography to obtain 1.07 g of product. This product is called "Compound 17".

[0080] [ka]

[0081] Compound 17 (1.00 g) and bromotrimethylsilane (4.16 g) were dissolved in dichloromethane (300 mL) and stirred at room temperature. Methanol was added to the reaction mixture, and the solvent was distilled off under reduced pressure. Methanol and water were added to the residue and stirred. The resulting solid was filtered to obtain 0.91 g of product. 1 H-NMR analysis revealed that the product was of the following formula: This product is designated "Compound 18".

[0082] [ka] 1 H-NMR(400MHz,DMSO-d6):δ 8.71-8.66 (4H, m), 7.48 (1H, t, 8.1), 7.39-7.37 (2H, m), 7.22 (1H, d, 8.1), 4.31-4.25 (2H, m), 2.54 (3H, s), 2.06-1.97 (2H, m)

[0083] <Example 9> DMF (50 mL) was added to naphthalene-1,4,5,8-tetracarboxylic dianhydride (1.00 g) and heated to 100°C. Diethyl 2-aminoethylphosphonate (0.68 g) was added to this mixture and heated to reflux. 4-aminopyridine (0.35 g) was further added and heated to reflux. The solvent was distilled off under reduced pressure, and the residue was purified by column chromatography to obtain 0.98 g of product. This product is called "Compound 19".

[0084] [ka]

[0085] Compound 19 (0.70 g) and bromotrimethylsilane (3.17 g) were dissolved in dichloromethane (200 mL) and stirred at room temperature. Methanol was added to the reaction mixture, and the solvent was distilled off under reduced pressure. Methanol and water were added to the residue and stirred. The resulting solid was filtered to obtain 0.63 g of product. 1 Analysis by H-NMR revealed that the product had the following formula: This product is designated "Compound 20".

[0086] [ka] 1 H-NMR(400MHz,DMSO-d6):δ 8.81 (2H, d, 6.2), 8.72-8.68 (4H, m), 7.55 (2H, d, 6.2), 4.31-4.25 (2H, m), 2.06-1.97 (2H, m)

[0087] <Example 10> DMF (50 mL) was added to naphthalene-1,4,5,8-tetracarboxylic dianhydride (1.00 g) and heated to 100°C. 2-aminoethyl diethyl phosphonate (0.68 g) was added to this mixture and heated to reflux. Furthermore, 4-amino-2,6-dimethylpyridine (0.46 g) was added and heated to reflux. The residue after distilling off the solvent under reduced pressure was purified by column chromatography to obtain 0.72 g of product. This product is called "Compound 21".

[0088] [ka]

[0089] Compound 21 (0.65 g) and bromotrimethylsilane (2.79 g) were dissolved in dichloromethane (200 mL) and stirred at room temperature. Methanol was added to the reaction mixture, and the solvent was distilled off under reduced pressure. Methanol and water were added to the residue and stirred. The resulting solid was filtered to obtain 0.54 g of product. 1 H-NMR analysis revealed that the product was represented by the following formula: This product was named "Compound 22."

[0090] [ka] 1 H-NMR(400MHz,DMSO-d6):δ 8.73-8.68 (4H, m), 7.28 (2H, br), 4.31-4.25 (2H, m), 2.71 (6H, s), 2.05-1.97 (2H, m)

[0091] <Fabrication of Perovskite Solar Cells> Compound 4, compound 6, compound 8, compound 10, compound 12, compound 14, compound 16, compound 18, compound 20, and compound 22 were dissolved in a dimethyl sulfoxide solution to prepare 2 mM solutions on the surface of transparent conductive glass having indium tin oxide deposited on the glass surface as a transparent conductive support. The solutions were then spin-coated and heated to 100° C. to form an n-type buffer layer.

[0092] Then, lead iodide, formamidinium iodide, lead bromide, methylammonium bromide, and cesium iodide were dissolved in a mixed solution (4 / 1) of N,N-dimethylformamide and dimethylsulfoxide to prepare a precursor solution of perovskite. The solution was spin-coated on the substrate on which the n-type buffer layer was formed, and then chlorobenzene was spin-coated to form a film. The substrate on which the solution was formed was heated to 100°C to form a perovskite layer (light absorbing layer).

[0093] Finally, gold was evaporated onto the substrate on which the p-type buffer layer was formed, to obtain the desired solar cell. The solar cell corresponds to the one shown in Figure 1. The solar cell performance was evaluated using a solar simulator (YSS-150A, Yamashita Denso Co., Ltd.) (AM1.5, 100 mW cm -2 ) was used for evaluation.

[0094] The compounds shown in Table 1 were used to prepare batteries by the above method, and the short-circuit current density (Jsc), open circuit voltage (Voc), fill factor (ff), and photoelectric conversion efficiency (PCE) were measured to evaluate the initial performance. Specifically, 10 to 12 batteries were prepared using each compound under the same conditions, and the parameters of the battery that showed the highest photoelectric conversion efficiency among them are summarized in Table 1. In addition, Table 1 also lists the results of a similar evaluation of compound 2 synthesized by the present inventors as a comparative example. In addition, FW in Table 1 is the forward voltage sweep, and BW is the reverse voltage sweep.

[0095] [Table 1]

[0096] The results in Table 1 show that the aromatic diimide derivatives of the present invention can be used in the n-type buffer layer of perovskite solar cells, can achieve good conversion efficiency, and are useful as compounds for use in the n-type buffer layer. [Industrial Applicability]

[0097] According to the present invention, a novel aromatic diimide derivative that can be used in the n-type buffer layer of a perovskite solar cell can be obtained. The novel aromatic diimide derivative of the present invention can be used as a photoelectric conversion element, etc. In addition, the photoelectric conversion element of the present invention is useful as a perovskite solar cell, a photodiode, a photosensor, etc.

Claims

1. An aromatic diimide derivative represented by general formula (I): 【Chemistry 1】 (In general formula (I), A is a phosphonic acid group, a phosphoric acid group, a sulfonic acid group, or a sulfate group, or a group corresponding to a salt thereof; R is a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, or a substituted alkyl group; a is an integer of 1 to 6; and b is 0 or 1.)

2. a substituent of the substituted aryl group or substituted heteroaryl group in the general formula (I) is selected from the group consisting of an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an amino group, an alkoxy group, a haloalkoxy group, an aryloxy group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an acyloxy group, an acylamino group, an alkoxycarbonylamino group, an aryloxycarbonylamino group, a sulfonylamino group, a sulfamoyl group, a carbamoyl group, an alkylthio group, an arylthio group, a sulfonyl group, a halogen atom, a cyano group, and a heterocyclic group; 2. The aromatic diimide derivative according to claim 1, wherein the substituent of the substituted alkyl group in the general formula (I) is selected from the group consisting of an amino group, an alkoxy group, a haloalkoxy group, an aryloxy group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an acyloxy group, an acylamino group, an alkoxycarbonylamino group, an aryloxycarbonylamino group, a sulfonylamino group, a sulfamoyl group, a carbamoyl group, an alkylthio group, an arylthio group, a sulfonyl group, a halogen atom, a cyano group, and a heterocyclic group.

3. 2. The aromatic diimide derivative according to claim 1, wherein R in the general formula (I) is an unsubstituted aryl group or an unsubstituted heteroaryl group.

4. The aromatic diimide derivative according to claim 1 , wherein b in the general formula (I) is 0.

5. 2. The aromatic diimide derivative according to claim 1, wherein A in the general formula (I) is a group corresponding to a phosphonic acid group or a salt thereof.

6. 2. The aromatic diimide derivative according to claim 1, wherein R in the general formula (I) is a substituted or unsubstituted aryl group, or a substituted or unsubstituted heteroaryl group, and the heteroaryl group contains, as a ring atom other than carbon atoms, at least one heteroatom selected from a nitrogen atom and a sulfur atom.

7. The aromatic diimide derivative according to claim 1, which is represented by general formulas (II) to (XI). 【Chemistry 2】 【Chemistry 3】

8. A photoelectric conversion element comprising the aromatic diimide derivative according to any one of claims 1 to 7.

9. A perovskite solar cell comprising the photoelectric conversion element according to claim 8.

10. A photodiode comprising the photoelectric conversion element according to claim 8 .

11. An optical sensor comprising the photoelectric conversion element according to claim 8 .

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