Photoelectric conversion element, photoelectric conversion device, mobile body, and building material

Abstract

A photoelectric conversion element (1) comprises: a first electrode (7); a second electrode (3); and a photoelectric conversion layer (5) that is disposed between the first electrode (7) and the second electrode (3) and that contains crystals having a perovskite structure. A first charge transport layer (8) is provided between the photoelectric conversion layer (5) and the first electrode (7), and a second charge transport layer (6) is provided between the first charge transport layer (8) and the first electrode (7). The second charge transport layer (6) contains a charge transport material and silver. The first charge transport layer (8) contains a cyclic conjugated compound in which a plurality of pyrrole rings having an axial ligand are conjugated. The initial photoelectric conversion efficiency is excellent, and the excellent photoelectric conversion efficiency is maintained even after long-term use.

Description

Photoelectric conversion elements, photoelectric conversion devices, mobile bodies, and building materials

[0001] This disclosure relates to photoelectric conversion elements, photoelectric conversion devices, mobile devices, and building materials.

[0002] In order to address the depletion of fossil fuels and the environmental problems caused by their use, research is actively being conducted on renewable and clean alternative energy sources such as solar, wind, and hydroelectric power. Among these, there is growing interest in solar cells, which directly convert sunlight into electrical energy. Here, a solar cell refers to a battery that absorbs light energy from sunlight and generates current and voltage using the photovoltaic effect, which generates electrons and holes.

[0003] Currently, n-p diode type silicon (Si) single-crystal based solar cells with a light energy conversion efficiency exceeding 20% ​​are widely known and actually used in photovoltaic power generation. However, these have the problem of high cost per unit of power due to the need for high-temperature processing and the high price of the material itself. Furthermore, there are supply issues from the perspective 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 using a so-called roll-to-roll method on a sheet-like substrate, thus offering the potential for lower costs. However, further improvements in power generation efficiency and durability are desired for the practical application of organic solar cells. In particular, perovskite-type solar cells, which have a perovskite structure crystal as the photoelectric conversion layer, are being developed for practical use because of their excellent photoelectric conversion properties.

[0005] For example, Patent Document 1 describes a configuration in which a compound having a phthalocyanine skeleton is included in the hole transport layer. Also, Patent Document 2 describes the effect of metal concentration in the hole transport layer on photoelectric conversion efficiency.

[0006] Japanese Patent Publication No. 2016-139805, International Publication No. 17 / 018529

[0007] According to the inventors' examination of the present disclosure, while the photoelectric conversion elements described in Patent Documents 1 and 2 show effectiveness in improving initial conversion efficiency, there was room for improvement in terms of maintaining conversion efficiency during long-term use while simultaneously improving initial conversion efficiency. Therefore, the object of the present disclosure is to provide a photoelectric conversion element that is excellent in initial photoelectric conversion efficiency and maintains excellent photoelectric conversion efficiency even after long-term use.

[0008] The above objectives are achieved by the present disclosure as follows: The present disclosure provides a photoelectric conversion element having a first electrode, a second electrode, and a photoelectric conversion layer comprising a perovskite crystal disposed between the first electrode and the second electrode, wherein the photoelectric conversion element has a first charge transport layer between the photoelectric conversion layer and the first electrode, a second charge transport layer between the first charge transport layer and the first electrode, the second charge transport layer contains a charge transport material and silver, and the first charge transport layer contains a cyclic conjugated compound formed by the conjugation bonding of a plurality of pyrrole rings having axial ligands. The present disclosure also provides a photoelectric conversion device having the above photoelectric conversion element. The present disclosure also provides a mobile body having the above photoelectric conversion element. The present disclosure also provides a building material having the above photoelectric conversion element. Furthermore, the present disclosure provides a photoelectric conversion element having a first electrode, a second electrode, and a photoelectric conversion layer containing a perovskite crystal disposed between the first electrode and the second electrode, wherein the photoelectric conversion element has a charge transport layer between the photoelectric conversion layer and the first electrode, the region of the charge transport layer on the first electrode side contains a charge transport material and silver, and the region of the charge transport layer on the photoelectric conversion layer side contains a cyclic conjugated compound in which a plurality of pyrrole rings having axial ligands are conjugated together.

[0009] According to this disclosure, it is possible to provide a photoelectric conversion element and a photoelectric conversion device that have excellent photoelectric conversion efficiency and maintain excellent photoelectric conversion efficiency even during long-term use.

[0010] This is a schematic cross-sectional view in the thickness direction of one embodiment of the photoelectric conversion element of the present disclosure. This is a schematic diagram showing one embodiment of a mobile body equipped with the photoelectric conversion element of the present disclosure. This is a schematic diagram showing one embodiment of a building material equipped with the photoelectric conversion element of the present disclosure.

[0011] <Photoelectric Conversion Element> The photoelectric conversion element of the present disclosure is a photoelectric conversion element having a first electrode, a second electrode, and a photoelectric conversion layer containing a perovskite structure crystal disposed between the first electrode and the second electrode, wherein the photoelectric conversion element has a first charge transport layer between the photoelectric conversion layer and the first electrode, a second charge transport layer between the first charge transport layer and the first electrode, the second charge transport layer contains a charge transport material and silver, and the first charge transport layer contains a cyclic conjugated compound in which a plurality of pyrrole rings having axial ligands are conjugated together.

[0012] As a result of their studies, the inventors of this disclosure have found that by having the first and second charge transport layers described above, a photoelectric conversion element is provided that exhibits excellent photoelectric conversion efficiency and maintains excellent photoelectric conversion efficiency even during long-term use. The reasons for the high effectiveness obtained in this disclosure are not entirely clear, but are thought to be as follows.

[0013] The photoelectric conversion element of this disclosure comprises a first electrode, a second electrode, and a photoelectric conversion layer comprising a perovskite crystal disposed between the first electrode and the second electrode. Furthermore, a first charge transport layer is provided between the photoelectric conversion layer and the first electrode, and a second charge transport layer is provided between the first charge transport layer and the first electrode, wherein the second charge transport layer contains a charge transport material and silver, and the first charge transport layer comprises a cyclic conjugated compound in which a plurality of pyrrole rings having axial ligands are conjugated together.

[0014] Specifically, for example, the device has first and second charge transport layers between the photoelectric conversion layer and the first electrode. During use, silver contained in the second charge transport layer located on the first electrode side moves to the photoelectric conversion layer side as a cation. In conventional configurations, since the charge transport layer and the photoelectric conversion layer are continuous, silver ions migrate to the photoelectric conversion layer, accelerating the degradation of the photoelectric conversion layer and leading to a decrease in photoelectric conversion efficiency. Silver ions have a larger ionic radius than lithium ions and other dopants that are commonly used in the past.

[0015] Therefore, although its mobility is relatively low, it is difficult to suppress its movement, making it challenging to inhibit the progression of migration. Consequently, while the excellent conductivity of silver ions contributes to improved initial photoelectric conversion efficiency, there were challenges in durability. In particular, when halogens were included in the photoelectric conversion layer, the high reactivity between silver and halogens significantly affected degradation due to migration.

[0016] On the other hand, in the configuration of this disclosure, it is hypothesized that by including a cyclic conjugated compound in the first charge transport layer, in which multiple pyrrole rings having axial ligands are conjugated together, it is possible to effectively trap silver ions and suppress the progression of migration to the photoelectric conversion layer. The crystal of the cyclic conjugated compound, in which multiple pyrrole rings having axial ligands are conjugated together, has a crystal structure in which the axial ligands protrude from the planar structure and repeats, so it is possible to have spaces, and it is thought that silver ions with relatively large ionic radii can be easily trapped in these spaces.

[0017] In addition, cyclic conjugated compounds, which consist of multiple pyrrole rings with axial ligands linked by conjugation, have axial ligands that protrude from the planar structure, resulting in a large moment with uneven charge distribution. It is thought that this charge imbalance creates an electrical force that traps silver ions. As a result, these compounds are expected to exhibit excellent photoelectric conversion efficiency and maintain that efficiency even during prolonged use.

[0018] Furthermore, it is believed that the adhesion durability of the interface can be improved by trapping silver ions moving from the second charge transport layer with a cyclic conjugated compound formed by the conjugation of multiple pyrrole rings with axial ligands in the first charge transport layer. This is thought to be because the cyclic conjugated compound, formed by the conjugation of multiple pyrrole rings with axial ligands in the first charge transport layer, traps silver ions with large ionic radii particularly strongly at the interface between the first and second charge transport layers.

[0019] As a result, it becomes possible to efficiently transfer charge between the first and second charge transport layers, resulting in excellent photoelectric conversion efficiency and the ability to maintain that excellent photoelectric conversion efficiency even during prolonged use.

[0020] Furthermore, it is believed that the energy levels at the interface between the first and second charge transport layers can be optimized by trapping silver ions moving from the second charge transport layer with a cyclic conjugated compound formed by the conjugation of multiple pyrrole rings having axial ligands in the first charge transport layer.

[0021] By trapping some of the silver ions acting as dopants in the second charge transport layer with a cyclic conjugated compound consisting of multiple pyrrole rings with axial ligands in the first charge transport layer, the energy levels of the first and second charge transport layers are brought closer together, enabling efficient charge transfer. As a result, it is thought that excellent photoelectric conversion efficiency can be achieved and maintained even during prolonged use.

[0022] The photoelectric conversion element of this disclosure has a first charge transport layer between the photoelectric conversion layer and the first electrode, and a second charge transport layer between the first charge transport layer and the first electrode.

[0023] [First Charge Transport Layer] The photoelectric conversion element of this disclosure includes a first charge transport layer comprising a cyclic conjugated compound formed by the conjugation of multiple pyrrole rings having axial ligands. The cyclic conjugated compound, formed by the covalent bonding of multiple pyrrole rings, has a planar structure in which the π-electron conjugation system extends throughout the entire molecule. By forming this cyclic conjugated compound as a charge transport material, it exhibits high hole transport properties. Furthermore, this cyclic conjugated compound can form complexes with various elements at the center of the ring, and axial ligands can be positioned in the vertical direction on the plane of the cyclic conjugated compound.

[0024] The cyclic conjugated compounds used in this disclosure, which consist of multiple pyrrole rings having axial ligands and are covalently bonded, are preferably porphyrin compounds or phthalocyanine compounds from the viewpoint of the expansion of the π-electron cloud that serves as the starting point for interactions. Among these, phthalocyanine compounds are more preferably used from the viewpoint of charge transport ability.

[0025] Specific examples of porphyrin compounds in this disclosure are listed below. (In the above formula (P-1), R １ ~R １２ Each of these independently represents an organic group containing a hydrogen atom, an optionally substituted aromatic group, or an optionally substituted aliphatic group. Specifically, hydrogen atoms, methyl groups, ethyl groups, propyl groups, isopropyl groups, butyl groups, octyloxy groups, butoxy groups, halogen atoms, phenyl groups, phenoxy groups, carboxyphenyl groups, benzenesulfonic acid groups, hydroxyphenyl groups, dihydroxyphenyl groups, trihydroxyphenyl groups, methoxyphenyl groups, dimethoxyphenyl groups, trimethoxyphenyl groups, methylphenyl groups, dimethylphenyl groups, trimethylphenyl groups, pyridyl groups, aminophenyl groups, sodium sulfonate bases, 4-cumylphenoxy groups, sulfonic acid groups, phenylthio groups, tert-butyl groups, hydroxyl groups, carbonyl groups, methoxy groups, amino groups, sulfo groups, and aldehyde groups are preferred.

[0026] Depending on the type and number of these molecules, it is possible to weaken the crystallinity to bring it closer to an amorphous state, or to give it solubility in solvents. For example, one branched alkyl molecule such as a tert-butyl group can be attached to each benzene ring (e.g., R １, R ３ , R ５ , R ７ When there are a total of four of them in (), the crystallinity tends to be low and the solubility tends to increase. X represents a metal atom, and Y represents an axial ligand, which will be specifically described later.

[0027] Specific examples of the phthalocyanine compound in the present disclosure are listed below. (In the above formula (P-2), R １３ ~R ２８ Each independently represents an organic group including a hydrogen atom, an aromatic group which may have a substituent, or an aliphatic group which may have a substituent, etc. Specifically, a hydrogen atom, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an octyloxy group, a butoxy group, a halogen atom, a phenyl group, a phenoxy group, a carboxyphenyl group, a benzenesulfonic acid group, a hydroxyphenyl group, a dihydroxyphenyl group, a trihydroxyphenyl group, a methoxyphenyl group, a dimethoxyphenyl group, a trimethoxyphenyl group, a methylphenyl group, a dimethylphenyl group, a trimethylphenyl group, a pyridyl group, an aminophenyl group, a sodium sulfonate group, a 4-cumylphenoxy group, a sulfonic acid group, a phenylthio group, a tert-butyl group, a hydroxy group, a carbonyl group, a methoxy group, an amino group, a sulfo group, an aldehyde group are preferred.)

[0028] Depending on the type and number of these substituents, the crystallinity can be weakened to approach an amorphous state, or the solubility in a solvent can be imparted. For example, when each benzene ring has one branched alkyl molecule such as a tert-butyl group (for example, R １５ , R １９ , R ２３ , R ２７ When there are a total of four of them in (), the crystallinity tends to be low and the solubility tends to increase. X represents a metal atom, and Y represents an axial ligand, which will be specifically described later.

[0029] The cyclic conjugated compounds in this disclosure, which consist of multiple pyrrole rings conjugated together, have a central element for having an axial ligand. This central element is represented by X in formulas (P-1) and (P-2). Various elements can be used as the central element, but Ga, Ti, V, Al, In, Fe, Si, Sn, and Mn are preferred due to their high charge transport capacity. Among these, Ga is preferred from the viewpoint of charge transport capacity.

[0030] In the photoelectric conversion element of the present disclosure, it is preferable that the axial ligand is at least one selected from halogen atoms, alkyl groups, aryl groups, carboxyl groups, alkoxy groups, hydroxyl groups, cyano groups, amino groups, and oxygen atoms. From the viewpoint of charge transport ability, it is preferable that the axial ligand of the photoelectric conversion element of the present disclosure is at least one selected from the group consisting of OH, Cl, and O.

[0031] The cyclic conjugated compounds in which multiple pyrrole rings are conjugated together in this disclosure have an axial ligand, and Y in formulas (P-1) and (P-2). ｎ This is shown. The cyclic conjugated compound, in which multiple pyrrole rings are conjugated together, has an axial ligand and therefore has a large moment and high charge transport capacity. The large moment is generated by having an axial ligand on one side of the planar structure. Y in formulas (P-1) and (P-2) ｎ The value n indicates the number of axial ligands and is either 1 or 2.

[0032] When there are two axial ligands, a moment is generated whether the two ligands coordinate from one side of the planar structure or whether there are different ligands on both sides of the planar structure, and thus the effects of this disclosure are realized. Preferably, when there is one axial ligand, the above interaction is more likely to occur, which is preferable. In the photoelectric conversion element of this disclosure, it is preferable that there is one axial ligand in the molecule of the phthalocyanine compound.

[0033] From the above viewpoint, it is more preferable that the phthalocyanine compound in the photoelectric conversion element of this disclosure is a hydroxygallium phthalocyanine compound.

[0034] In the photoelectric conversion element of this disclosure, it is preferable that the cyclic conjugated compound is a pigment. The charge transport ability can be further improved if the cyclic conjugated compound is a pigment. Furthermore, it is preferable that the average particle size of the pigment is 10 nm to 400 nm, and more preferably 50 nm to 300 nm. Within this particle size range, the charge transport ability can be further improved.

[0035] In the photoelectric conversion element disclosed herein, it is preferable that the first charge transport layer contains a calixarene compound. By including a calixarene compound, excellent photoelectric conversion efficiency can be maintained even during longer periods of use. This is thought to be because the cyclic conjugated compound, in which multiple pyrrole rings are conjugated together, interacts with the calixarene compound, allowing for a stronger interaction with silver ions moving from the second charge transport layer. As a result, it is presumed that the effect of trapping silver ions can be enhanced.

[0036] In the photoelectric conversion element of this disclosure, it is preferable that the calixarene compound is represented by the following formula (A). (In the above formula (A), R ３１ ~R ３５ R is independent within each repeating unit and independently for each of the n repeating units. ３１ R represents a hydrogen atom or an alkyl group. ３２ R represents a substituted or unsubstituted alkylene group. ３３ ~R ３５ R 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. ３３ ~R ３５ At least one of these is a substituted -Y-Ar group. The -Y- represents -CH=N-, -CH=CH-, or -N=N-, and the Ar is a substituted or unsubstituted aromatic hydrocarbon group, or a substituted or unsubstituted heterocyclic group. n is an integer between 3 and 20.

[0037] The above R ３１ and R ３３ ~R３５ Examples of alkyl groups mentioned include methyl, ethyl, propyl, and butyl groups. ３３ ~R ３５ Examples of aromatic hydrocarbon groups mentioned include benzene, naphthalene, fluorene, phenanthrene, anthracene, fluorantene, and pyrene. Also, the above R ３３ ~R ３５ Examples of heterocyclic groups mentioned include furan, thiophene, pyridine, indole, benzothiazole, carbazole, benzocarbazole, acridone, dibenzothiophene, benzoxazole, benzotriazole, oxathiazole, thiazole, phenazine, cinnoline, and benzosinnoline.

[0038] Also, R ３３ ~R ３５ Examples of substituents that alkyl groups, phenylazo groups, aromatic hydrocarbon groups, and heterocycles may have include alkyl groups such as methyl, ethyl, propyl, and butyl groups; alkoxy groups such as methoxy and ethoxy groups; dialkylamino groups such as dimethylamino and diethylamino groups; alkoxycarbonyl groups such as methoxycarbonyl and ethoxycarbonyl groups; halogen atoms such as fluorine, chlorine, and bromine atoms; hydroxyl groups, nitro groups, cyano groups, and halomethyl groups.

[0039] In the photoelectric conversion element of the present disclosure, n in formula (A) is preferably 4 or 8, from the viewpoint of charge extraction and transfer, and excellent photoelectric conversion efficiency can be maintained even during use for longer periods of time.

[0040] Furthermore, the photoelectric conversion element of the present disclosure is R of formula (A) above. ３４ However, it is preferable from the viewpoint of charge extraction and transfer that each of the n repeating units independently has a nitrophenylazo group or a dinitrophenylazo group.

[0041] Furthermore, in the photoelectric conversion element of the present disclosure, it is preferable that the molecular weight of the calixarene compound of formula (A) is 10,000 or less, from the viewpoint of charge extraction and transfer, and excellent photoelectric conversion efficiency can be maintained even during use for longer periods of time.

[0042] Furthermore, in this disclosure, R ３１ However, it is preferable that each of the n repeating units is independently hydrogen or a methyl group, an ethyl group, or a propyl group. Also, R ３２ However, it is preferable that each of the n repeating units independently consists of a methylene group, an ethylene group, or a propylene group. ３３ , R ３５ However, it is preferable that it be a hydrogen atom.

[0043] In the photoelectric conversion element of the present disclosure, it is preferable from the viewpoint of charge extraction and transfer that the calixarene compound of formula (A) is a mixture of the compound shown in formula (C-1), the compound shown in formula (C-2), the compound shown in formula (C-3), and the compound shown in formula (C-4), and that excellent photoelectric conversion efficiency can be maintained even during use for longer periods of time.

[0044] From the viewpoint of interaction strength, it is preferable that the ratio of the mass of the calixarene compound contained in the first charge transport layer to the mass of the cyclic conjugated compound, which is formed by the conjugation of multiple pyrrole rings contained in the first charge transport layer, is in the range of 0.002 to 0.8. Furthermore, it is more preferable that it is in the range of 0.005 to 0.5. In the photoelectric conversion element of the present disclosure, it is preferable that the ratio of the mass of the calixarene compound to the mass of the phthalocyanine compound in the first charge transport layer is 0.002 to 0.8. This is preferable in that it can suppress the accumulation of charge that occurs during the extraction and transfer of charge between the cyclic conjugated compound, which is formed by the conjugation of multiple pyrrole rings. As a result, excellent photoelectric conversion efficiency can be maintained even during use for longer periods of time.

[0045] The photoelectric conversion element of the present disclosure preferably has a first charge transport layer that contains a compound that improves current density, and can maintain excellent photoelectric conversion efficiency even during longer periods of use. The compound that improves current density is preferably a dopant material or an ionic liquid material. Examples of dopant materials include the materials described in Non-Patent Literature (J. Lee, et al., EcoMat vol. 5, p. e 12414 (2023)).

[0046] The combination of cations and anions is not limited. Examples of cations in ionic liquid materials include imidazolium salts, pyrrolidinium salts, pyridinium salts, piperidinium salts, ammonium salts, phosphonium salts, and sulfonium salts. Examples of anions include the following:

[0047] In this disclosure, it is preferable that the ratio of the mass of the compound that improves the current density to the mass of the calixarene compound is 0.002 or more and 10 or less, in that it is possible to suppress the accumulation of charge that occurs due to the extraction and transfer of the increased charge due to the improvement in charge transport capacity. As a result, excellent photoelectric conversion efficiency can be maintained even during use for longer periods of time.

[0048] In this disclosure, it is preferable that the ratio of the mass of the compound that improves the current density to the mass of the cyclic conjugated compound formed by the conjugation of the plurality of pyrrole rings is 0.0001 or more and 1 or less, in that the charge transport capacity in the charge transport layer can be further improved.

[0049] In the photoelectric conversion element of this disclosure, it is preferable that the first charge transport layer contains a resin. Adding a resin is preferable because it suppresses the formation of voids in the charge transport layer, enhances adhesion between materials, improves charge transport ability, and suppresses stagnation that occurs during charge extraction and transfer.

[0050] Furthermore, in order to suppress the formation of voids, the SP value and functional groups of the resin can be appropriately selected. Examples of functional groups include hydroxyl groups, carbonyl groups, ester groups, ether groups, carboxyl groups, methoxy groups, amino groups, sulfo groups, aldehyde groups, amide groups, halogens, sulfide groups, cyano groups, thienyl groups, pyridine, furan, pyrazole, imidazole, oxazole, and thiazole.

[0051] In the photoelectric conversion element of this disclosure, it is preferable that the resin is an insulating resin. If it is an insulating resin, the charge rectification required for the photoelectric conversion element can be maintained. The volume resistivity of the charge transport insulating resin is 1.0 × 10⁻⁶. ９ Preferably Ω·cm or more, and more preferably 1.0 × 10 １０ Ω・cm or more, 1.0×10 １５ A value of Ω·cm or less is more preferable.

[0052] In this disclosure, it is preferable that the ratio of the mass of the cyclic conjugated compound, in which multiple pyrrole rings are conjugated together, to the mass of the resin is 5 or more and 30 or less, in order to further improve the charge transport capacity in the charge transport layer. As a result, excellent photoelectric conversion efficiency can be maintained even during use for longer periods of time.

[0053] Furthermore, in this disclosure, it is preferable that the ratio of the mass of the calixarene compound to the mass of the resin is 0.2 or more and 50 or less, in that it can suppress the accumulation of charge that occurs during charge extraction and transfer. As a result, excellent photoelectric conversion efficiency can be maintained even during use for longer periods of time.

[0054] Furthermore, in this disclosure, it is preferable that the ratio of the mass of the compound that improves the current density to the mass of the resin is 0.002 or more and 10 or less, in that the charge transport capacity in the charge transport layer can be further improved. As a result, excellent photoelectric conversion efficiency can be maintained even during use for longer periods of time.

[0055] The thickness of the first charge transport layer is preferably 5 nm to 800 nm. If the thickness is 5 nm or more, an effect of suppressing interlayer migration can be expected, and if the thickness is 800 nm or less, it is easier to transport charge to each electrode efficiently. More preferably, it is 40 nm to 600 nm, and even more preferably 40 nm to 400 nm. By changing the thickness, the smoothness of the surface can be controlled, and an improvement in the charge transport ability at the interface can be expected.

[0056] [Second Charge Transport Layer] The photoelectric conversion element of the present disclosure has a second charge transport layer between the first charge transport layer and the first electrode. The second charge transport layer of the photoelectric conversion element of the present disclosure contains a charge transport material and silver. The silver contained in the second charge transport layer may be ionized or not.

[0057] The charge transport material contained in the second charge transport layer is not particularly limited and includes, for example, spirofluorene compounds, triphenylamine compounds, chrysene compounds, pyrene compounds, phthalocyanine compounds, carbazole compounds, fluorene compounds, phenylcyclohexane compounds, benzidine compounds, phenoxazine compounds, phenylenediamine compounds, thiocyanate compounds, and thiophene compounds. In particular, it is preferable that the material has an aromatic ring from the viewpoint of compatibility at the membrane interface, and Spiro-OMeTA, PTAA, and phthalocyanine compounds are preferred. The charge transport material may be a polymer or not.

[0058] In this disclosure, it is preferable that the second charge transport layer, like the first charge transport layer, contains a compound that improves current density. The compound that improves current density is preferably a dopant material or an ionic liquid material, which can maintain excellent photoelectric conversion efficiency even during longer periods of use. Examples of dopant materials include those described in Non-Patent Literature (J. Lee, et al., EcoMat vol. 5, p. e 12414 (2023)). The combination of cations and anions is not limited.

[0059] Examples of cations in ionic liquid materials include imidazolium salts, pyrrolidinium salts, pyridinium salts, piperidinium salts, ammonium salts, phosphonium salts, and sulfonium salts. Examples of anions include the following:

[0060] The above anion may be contained as an ionic compound bonded to a charge transport material cation. Furthermore, it is preferable that the silver contained in the second charge transport layer exists as a counter-cation of the above anion. This is because it has a large ionic radius and is effective in suppressing migration through the above mechanism.

[0061] Similar to the first charge transport layer, the second charge transport layer may contain a resin. Adding a resin is preferable because it suppresses the formation of voids in the second charge transport layer, enhances adhesion between materials, improves charge transport capacity, and suppresses stagnation that occurs during charge extraction and transfer.

[0062] Furthermore, in order to suppress the formation of voids, the SP value and functional groups of the resin can be appropriately selected. Examples of functional groups include hydroxyl groups, carbonyl groups, ester groups, ether groups, carboxyl groups, methoxy groups, amino groups, sulfo groups, aldehyde groups, amide groups, halogens, sulfide groups, cyano groups, thienyl groups, pyridine, furan, pyrazole, imidazole, oxazole, and thiazole.

[0063] It is preferable that the resin is an insulating resin. If it is an insulating resin, the charge rectification required for the photoelectric conversion element can be maintained. The volume resistivity of the charge transport insulating resin is 1.0 × 10⁻⁶. ９ Preferably Ω·cm or more, and more preferably 1.0 × 10 １０ Ω・cm or more, 1.0×10 １５ A value of Ω·cm or less is more preferable.

[0064] The thickness of the second charge transport layer is preferably 1 nm to 1000 nm, more preferably 5 nm to 500 nm, and particularly preferably 10 nm to 200 nm.

[0065] The photoelectric conversion element of the present disclosure has a ratio of the weight concentration of silver in the second charge transport layer to the weight concentration of a cyclic conjugated compound formed by the conjugation bonding of a plurality of pyrrole rings having axial ligands in the first charge transport layer, which is 0.4 × 10⁻⁶. －５ Preferably, the ratio is between 10 and 17 times. In the photoelectric conversion element of the present disclosure, the ratio of the mass concentration of silver in the second charge transport layer to the mass concentration of the phthalocyanine compound in the first charge transport layer is 0.4 × 10⁻⁶. －５ It is preferable that the ratio is between 1 / 2 and 17 / 2. By keeping it within this range, the migration suppression by the above mechanism can be effectively achieved.

[0066] The photoelectric conversion element of the present disclosure has a ratio of the mass concentration of silver in the second charge transport layer to the mass concentration of calixarene compound in the first charge transport layer, which is 0.9 × 10⁻⁶. －４ It is preferable that the ratio is between 2x and 8333x. By keeping it within this range, the migration suppression by the above mechanism can be effectively achieved.

[0067] The first charge transport layer and the second charge transport layer may be integrated without an interface (in which case, the integrated unit is also simply referred to as the "charge transport layer" in this disclosure). In this case, the disclosure provides a photoelectric conversion element having a first electrode, a second electrode, and a photoelectric conversion layer containing a perovskite crystal disposed between the first electrode and the second electrode, wherein the photoelectric conversion element has a charge transport layer between the photoelectric conversion layer and the first electrode, the region of the charge transport layer on the first electrode side contains a charge transport material and silver, and the region of the charge transport layer on the photoelectric conversion layer side contains a cyclic conjugated compound in which a plurality of pyrrole rings having axial ligands are conjugated together.

[0068] [Surface Modification Layer] The photoelectric conversion element of the present disclosure preferably has a surface modification layer between the first charge transport layer and the second charge transport layer. The material of the surface modification layer is not particularly limited, and preferably contains, for example, a dopant material, an ionic liquid material, or a passivation material.

[0069] By having a surface modification layer between the second charge transport layer and the first electrode, charge retention in the second charge transport layer is reduced, and charge can be efficiently transferred to the layer located opposite the photoelectric conversion layer. Furthermore, by appropriately configuring the wettability and interface states with the surface modification layer, charge can be transferred even more efficiently, improving the photoelectric conversion efficiency.

[0070] Examples of the aforementioned passivation materials include the following:

[0071] The thickness of the surface modification layer is preferably 100 nm or less. A thickness of 100 nm or less facilitates good charge transport. More preferably, it is 0.1 nm to 20 nm. The surface modification layer can also be formed by migrating the compound in the composition to the surface during coating. For surface migration, it is preferable that the compound forming the surface modification layer has an element or structure with low surface free energy, such as fluorine or siloxane.

[0072] As described above, the effects of this disclosure can be achieved through the synergistic effects of each component. The contents of this disclosure will be described in detail below with reference to preferred embodiments. This disclosure is not limited to the embodiments described below, and the scope of this disclosure also includes modifications, improvements, etc., to the embodiments described below, made based on the ordinary knowledge of a person skilled in the art, without departing from the spirit of this disclosure.

[0073] In this specification, the term "layer" refers not only to layers with clear boundaries or flat, thin films, but also to layers with gradually changing elemental concentrations and layers that can combine with other layers to form complex structures. Furthermore, layer analysis can be performed, for example, by measuring using MS / NMR / XPS / IR / XRD / TEM / SEM / EDS / SPM to confirm the compounds contained in the layer and the layer's composition.

[0074] Figure 1 is a schematic cross-sectional view showing the configuration of one embodiment of the photoelectric conversion element of the present disclosure. The photoelectric conversion element of the present disclosure has a first electrode 7, a second electrode 3, and a photoelectric conversion layer 5 containing a perovskite crystal disposed between the first electrode 7 and the second electrode 3.

[0075] A first charge transport layer 8 is provided between the photoelectric conversion layer 5 and the first electrode 7, and a second charge transport layer 6 is provided between the first charge transport layer 8 and the first electrode 7. The substrate 2 has a second electrode 3, an electron transport layer 4, a photoelectric conversion layer 5, a first charge transport layer 8, a second charge transport layer 6, and a first electrode 7. One of the first electrode 7 and the second electrode 3 is a positive electrode and the other is a negative electrode, and current can be extracted by connecting the first electrode 7 and the second electrode 3 to an external circuit.

[0076] 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 through the first electrode 7, the first charge transport layer 8, and the second charge transport layer 6, generating electrons or holes. That is, the photoelectric conversion layer 5 generates an electric current between the first electrode 7 and the second electrode 3.

[0077] The electron transport layer 4 is a layer placed between the photoelectric conversion layer 5 and the two electrodes (second electrode 3 and first electrode 7), and may not be formed in some cases. Multiple electron transport layers 4 and photoelectric conversion layers 5 may be stacked. Such a configuration can also be called a tandem structure. Alternatively, the photoelectric conversion element may be fabricated on the substrate 2 in the following order: first electrode 7, second charge transport layer 6, first charge transport layer 8, photoelectric conversion layer 5, electron transport layer 4, and second electrode 3.

[0078] The components constituting the photoelectric conversion element of this disclosure are described below. [Photoelectric Conversion Element] The photoelectric conversion element of this disclosure is characterized by having a photoelectric conversion layer containing a perovskite structure crystal, a first charge transport layer, and a second charge transport layer. The configuration of the photoelectric conversion element may be either a forward layer configuration in which a layer having P-type semiconductor characteristics is formed after the photoelectric conversion layer, or an inverse layer configuration in which a layer having N-type semiconductor characteristics is formed after the photoelectric conversion layer. The photoelectric conversion elements to be stacked are not limited to the type of photoelectric conversion element, but include not only perovskite solar cells that use a perovskite structure crystal as the photoelectric conversion layer, but also silicon solar cells, CIGS solar cells, etc.

[0079] Methods for forming each layer of the photoelectric conversion element disclosed herein include coating methods and vapor deposition methods. Examples of coating methods include immersion 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 involves preparing the coating solution for each layer, which will be described later, coating the layers in the desired order, and drying them. These film formation methods can be selected according to the requirements of each layer.

[0080] The following describes each layer. [Substrate] The photoelectric conversion element 1 of this disclosure may include a substrate 2, for example, a transparent glass substrate made of soda-lime glass or alkali-free glass, a ceramic substrate, or a transparent plastic substrate. When light is taken in from the first electrode 7 side, the substrate 2 can be made of an opaque material, and when light is taken in from the second electrode 3 side, the substrate 2 is made of a transparent material.

[0081] [Electrodes] The materials of the first electrode 7 and the second electrode 3 are not particularly limited, and conventionally known materials can be used. For example, metals such as gold, silver, titanium, and copper; sodium; sodium-potassium alloys; lithium; magnesium; carbon; carbon nanotubes; aluminum; magnesium-silver mixtures; magnesium-indium mixtures; aluminum-lithium alloys; Al / Al ２ O ３ Examples include mixtures and Al / LiF mixtures. Examples of transparent electrode materials include CuI, ITO (indium tin oxide), and SnO.２ Examples include conductive transparent materials and conductive transparent polymers such as AZO (aluminum zinc oxide), IZO (indium zinc oxide), GZO (gallium zinc oxide), FTO (fluorine-doped tin oxide), and ATO (antimond-doped tin oxide). These materials may be used individually or in combination of two or more.

[0082] The first electrode 7 and the second electrode 3 are configured such that at least one electrode on the light incidence side is a transparent electrode, and the other electrode may be a transparent electrode or a reflective layer made of a light-reflective material, or a transparent electrode with a reflective layer on the side opposite to the light incidence side. When the first electrode 7 is on the light incidence side, the second electrode 3 may be a transparent electrode and the substrate 2 may be a reflective layer. The transparent electrode may also be a patterned electrode.

[0083] [Photoelectric Conversion Layer] The photoelectric conversion layer 5 has a perovskite crystal structure. The perovskite crystal structure in this disclosure is preferably represented by the following general formula [1]. A ｏ B ｐ Z ｑ [1]

[0084] In the above general formula [1], A is a cation, B is a cation, and Z is an anion. o, p, and q satisfy 0 < o ≤ 10, 0 < p ≤ 10, and 0 < q ≤ 20, respectively. A, B, and Z may be composed of a single material or two or more materials may be used in combination. Additives may be added within the range that the above general formula holds true.

[0085] The above general formula generally forms a three-dimensional perovskite crystal. However, if the constituent cation A is large enough to fit within the three-dimensional perovskite crystal, it can form a two-dimensional perovskite crystal, a 2.5-dimensional perovskite crystal possessing properties of both two and three dimensions, a two-layer crystal with three-dimensional and two-dimensional perovskite structures, or a crystal with a mixed three-dimensional / two-dimensional perovskite structure, all of which function as a photoelectric conversion layer.

[0086] A two-layer crystal of three-dimensional and two-dimensional perovskite refers to a crystal in which three-dimensional and two-dimensional perovskite crystals are stacked as independent, separate layers, while a mixed three-dimensional / two-dimensional perovskite refers to a crystal in which regions or domains of both two-dimensional or 2.5-dimensional layered and three-dimensional perovskite crystals are mixed. Two-dimensional perovskite or 2.5-dimensional perovskite crystals may form RP (Ruddlesden-Popper), DJ (Dion-Jacobson), or ACI (Alternating Cautions in the Interlayer) type perovskite structures.

[0087] The type of cation A in the above general formula [1] is not particularly limited. A may or may not have substituents, and the following structural formulas are examples.

[0088] Furthermore, while the inorganic atoms are not particularly limited, lithium, cesium, sodium, potassium, and rubidium are preferred. These organic molecules or inorganic atoms may be used individually, or two or more may be used in combination.

[0089] In the general formula [1] above, B is a cation atom, and examples include lead, tin, bismuth, zinc, titanium, antimony, nickel, iron, cobalt, silver, copper, gallium, germanium, magnesium, calcium, indium, aluminum, manganese, chromium, molybdenum, and europium. Among these, lead, tin, bismuth, and silver are preferred from the viewpoint of the stability of the perovskite crystal structure. These atoms may be used individually or in combination of two or more.

[0090] In the general formula [1] above, Z is a halogen or chalcogen atom, and examples thereof include chlorine, bromine, iodine, oxygen, sulfur, selenium, tellurium, and polonium. These halogen or chalcogen atoms may be used alone or in combination of two or more. Among them, by containing halogen in the structure, the crystal of the perovskite structure is likely to be soluble in an organic solvent, and it becomes possible to apply it to an inexpensive printing method or the like. Therefore, a halogen atom is preferable. Further, since the energy band gap of the crystal of the perovskite structure becomes narrow, iodine is more preferable.

[0091] Specifically, the three-dimensional perovskite, two-dimensional perovskite, and mixed three-dimensional / two-dimensional perovskite are MAPbI ３ or FAPbCl ３ , FAPbI ３ , 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 , (FAPbI ３ ) ０．９５ (MAPbBr ３ ) ０．０５ , (FAPbI ３ ) ０．８５ (MAPbBr ３ ) ０．１５ , CsPbI ３ , CsPbBr ３ , Cs ｘ (MA) １－ｘ PbI ３ , Cs ｘ(FA) １－ｘ PbI ３ 、MA ｘ (FA) １－ｘ PbI ３ 、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 、(PEA) ２ (MA) ２ Pb ３ I １０ 、(PTA) ２ (MA) ４ Pb ５ I １６ ,(PEA) ２ (MA) ４ Pb ５ I １６ ,(ThMA) ２ (MA) ２ Pb ３ I １０ 、(3BBA) ２ (MA) ２ Pb ３ I １０ 、(ThMA) ２ (FA) ４ Pb ５ I １６ 、(pF-PEA) ２ (FA ０．３ MA ０．７ ) ４ Pb ５ I １６ 、(PDMA)FA ２ Pb ３ I １０ 、(3AMPY)(MA) ３ Pb ４ I １３ ,(PDMA)MA ５ Pb ６ I１９ , (PDMA)MA ３ Pb ４ I １３ , (BA ０．９ PEA ０．１ ) ２ MA ４ Pb ５ I １６ , (BA ０．９ PEA ０．１ ) ２ MA ３ Pb ４ I １３ , (BA) ２ , MA ２ Pb ３ I １０ , (BA) ２ MA ３ Pb ４ I １３ , (BA) ２ MA ４ Pb ５ I １６ , (BA) ２ MA ３ Pb ４ I １３ , CsSnBr ３ , CsSnI ３ , FA ０．７５ MA ０．２５ Sn ０．９５ Ge ０．０５ I ３ , FAMASnGeI ３ , FASnBr ３ , FASnI ３ , MA ２ Sn ３ I ８ , MASnBr ３ , MASnGeI ３ , MASnI ３ are preferred.

[0092] Depending on the purpose, the A site, B site, or Z site in the above general formula [1] may be adjusted to be too little or too much, and the combinations of x1 to x5 may be changed depending on the purpose. Examples of combinations of x1 to x5 are shown in Table 1. Particularly preferred ranges are 0.03 ≤ x1 ≤ 0.10, 0.80 ≤ x2 ≤ 0.96, 0.95 ≤ x3 ≤ 1.05, 0.80 ≤ x4 ≤ 0.96, and 2.95 ≤ x5 ≤ 3.05. MACL may also be included as the material for forming the perovskite crystal.

[0093]

[0094] The perovskite crystal described above preferably has a cubic crystal structure in which a metal atom B is located at the body center, organic molecules A are located at each vertex, and halogen atoms Z are located at the face centers. Although the details are not clear, it is presumed that having such a structure allows the orientation of the octahedra within the crystal lattice to change easily, thereby increasing the electron mobility in the perovskite crystal and improving the photoelectric conversion efficiency of the photoelectric conversion element.

[0095] In this disclosure, the perovskite crystal is preferably a crystalline semiconductor. A crystalline semiconductor is a semiconductor in which the X-ray scattering intensity distribution can be measured and a scattering peak can be detected. Because the perovskite crystal is a crystalline semiconductor, the electron mobility in the perovskite crystal is increased, improving the photoelectric conversion efficiency of the photoelectric conversion element.

[0096] The thickness of the photoelectric conversion layer in this disclosure is preferably 5 nm or more and 2000 nm or less. If the thickness is 5 nm or more, light can be absorbed sufficiently, and if it is 2000 nm or less, the generated charge can be transported to each electrode. A more preferable lower limit is 50 nm or more, a more preferable upper limit is 1200 nm, an even more preferable lower limit is 100 nm, and an even more preferable upper limit is 1000 nm.

[0097] [Electron Transport Layer] In the photoelectric conversion element of this disclosure, an electron transport layer 4 may be placed between the second electrode 3 and the photoelectric conversion layer 5, as shown in Figure 1.

[0098] The material of the electron transport layer 4 is not particularly limited, and examples include N-type conductive polymers, N-type low molecular weight organic semiconductors, N-type metal oxides, N-type metal sulfides, alkali metal halides, alkali metals, surfactants, etc. Specifically, examples include cyano group-containing polyphenylene vinylene, boron-containing polymers, vasocuproin, vasophenanthrene, hydroxyquinolinatoaluminum, oxadiazole compounds, benzimidazole compounds, naphthalenetetracarboxylic acid compounds, fullerene compounds, perylene compounds, phosphine oxide compounds, phosphine sulfide compounds, fluoro group-containing phthalocyanines, titanium dioxide, zinc oxide, indium oxide, tin oxide, gallium oxide, tin sulfide, indium sulfide, and zinc sulfide.

[0099] The preferred lower limit for the thickness of the electron transport layer 4 is 1 nm, and the preferred upper limit is 2000 nm. If the thickness is 1 nm or more, holes can be sufficiently blocked, and if it is 2000 nm or less, it will not be a resistance during electron transport, and the photoelectric conversion efficiency will be high. A more preferred lower limit for the thickness is 3 nm, a more preferred upper limit is 1000 nm, an even more preferred lower limit is 5 nm, and an even more preferred upper limit is 500 nm.

[0100] [Intermediate Layer] The photoelectric conversion element 1 may have one or more intermediate layers between each layer for the purpose of reducing energy gaps that hinder charge transfer or suppressing migration between layers. The intermediate layer contains either an inorganic compound or an organic compound. Examples of inorganic compounds include Al compounds, Mo compounds, Ni compounds, Ti compounds, Sn compounds, and Zn compounds.

[0101] Furthermore, examples of organic compounds include fullerene compounds, phthalocyanine compounds, spirofluorene compounds, triphenylamine compounds, chrysene compounds, pyrene compounds, phthalocyanine compounds, carbazole compounds, fluorene compounds, phenylcyclohexane compounds, benzidine compounds, phenoxazine compounds, phenylenediamine compounds, thiocyanate compounds, butyral resins, acrylic resins, polycarbonate resins, polyester resins, polyvinyl acetal resins, epoxy resins, melamine resins, polyurethane resins, phenolic resins, polyvinylphenol resins, alkyd resins, polyvinyl alcohol resins, polyethylene oxide resins, polypropylene oxide resins, polyamide resins, polyamic acid resins, polyimide resins, polyamideimide resins, and cellulose resins. These compounds may be used individually or in combination of two or more.

[0102] Furthermore, passivation materials and dopant materials can be used in combination to modify the surface or improve mobility. These compounds can be mixed into the layer, or brought into contact with / adhered to the surface by rinsing, as possible manufacturing methods.

[0103] The thickness of the intermediate layer is preferably 5 nm to 800 nm. If the thickness is 5 nm or more, an effect of suppressing interlayer migration can be expected, and if the thickness is 800 nm or less, charge can be easily transported to each electrode. More preferably, it is 40 nm to 600 nm, and even more preferably 40 nm to 400 nm.

[0104] <Application Examples> [Photoelectric Conversion Device] The photoelectric conversion device of the present disclosure has a photoelectric conversion element of the present disclosure. A photoelectric conversion device can be constructed by using multiple photoelectric conversion elements of the present disclosure. When multiple photoelectric conversion elements are connected together, such a photoelectric conversion device can also be called a photoelectric conversion cell or a photoelectric conversion module. The photoelectric conversion elements may be stacked with elements having different absorption wavelengths in order to increase the output voltage. The photoelectric conversion device also has a photoelectric conversion element of the present disclosure and an inverter.

[0105] An inverter may be a converter that converts direct current to alternating current. A photoelectric converter may have a power storage unit connected to a photoelectric converter element. The power storage unit is not limited as long as it can store electricity. Examples include lithium-ion secondary batteries, all-solid-state batteries, and electric double-layer capacitors. To provide functions such as maintaining or increasing the amount of incident light, a surface that is resistant to water and dirt, or a function to collect or guide light may be added.

[0106] [Mobile Body] The mobile body of the present disclosure has a photoelectric conversion element of the present disclosure. Figure 2 is a schematic perspective view showing one embodiment of a mobile body equipped with the photoelectric conversion element of the present disclosure. The mobile body 30 has a photoelectric conversion element 31 of the present disclosure and a body 32 equipped with the photoelectric conversion element 31. The photoelectric conversion element 31 is positioned in a location on the body 32 that can receive ambient light. If the mobile body 30 is an automobile, the photoelectric conversion element 31 may be placed on the roof. The electrical energy obtained by the photoelectric conversion element 31 may be used to power the mobile body 30 or other electrical equipment. The electrical energy generated from the power of the mobile body 30 may be used to power the photoelectric conversion element 31. If the mobile body 30 is an automobile, the frictional energy generated by the brakes may be converted into electrical energy and used to control the photoelectric conversion element 31.

[0107] The mobile body 30 may be, for example, an automobile, a motorcycle, a railway vehicle, a ship, a satellite, an airplane, or a drone. The structure of the mobile body 32 is not particularly limited, but it is preferably made of a high-strength material.

[0108] [Building Material] The building material of the present disclosure has a photoelectric conversion element of the present disclosure. Figure 3 is a schematic perspective view showing one embodiment of the building material equipped with the photoelectric conversion element of the present disclosure. The building material 40 may be the roof of a building. The building material 40 of this embodiment has a photoelectric conversion element 41 of the present disclosure, a protective member 42 for protecting the photoelectric conversion element 41, a heat dissipation member 43, and exterior parts 44a and 44b.

[0109] The building material 40 of this disclosure may have a heat dissipation member 43 with a higher thermal conductivity than the photoelectric conversion element 41. Generally, when a building material equipped with a photoelectric conversion element is used on a roof or the like, the temperature of the photoelectric conversion element 41 may rise due to sunlight, which may reduce the photoelectric conversion efficiency. In this case, the reduction in photoelectric conversion efficiency can be reduced by using a heat dissipation member 43. Examples of heat dissipation members 43 include metals, alloys, liquid metals, liquid resins, and the like.

[0110] Furthermore, the building material 40 of this disclosure may have exteriors 44a and 44b. Exteriors 44a and 44b may emit different colors or the same color. 44a and 44b may be composed of the same material or different materials. As the exterior material, paint or a transparent substrate may be used, and it is preferable to use one that has low light absorption and high heat shielding properties.

[0111] In addition to the above examples of applications, the following are some other examples of applications: Portable devices include calculators, sensors, and small solar panels. Wearable devices include eyeglasses, smartwatches, and portable medical devices. Sheet structures supported by multiple frames include tents, greenhouses, and truck beds. Fixed structures include road panels, floating panels, building materials that utilize the flexibility of the substrate, wall-type building materials, glass-type building materials, and mega solar panels.

[0112] <Method for Manufacturing a Photoelectric Conversion Element> The method for manufacturing a photoelectric conversion element according to the present disclosure includes the steps of forming a first electrode, forming a second electrode, forming a photoelectric conversion layer containing a perovskite crystal between the first electrode and the second electrode, and forming a charge transport layer between the photoelectric conversion layer and the first electrode. Each step of the manufacturing method will be described below.

[0113] [Process for forming the first electrode and the process for forming the second electrode] In the process for forming the first electrode and the process for forming the second electrode, an appropriate method can be selected according to the material of the first electrode and the material of the second electrode, respectively. Examples of such methods include, but are not limited to, sputtering, vacuum deposition, CVD (vapor deposition), and SPD (spray pyrolysis deposition). The materials of the first and second electrodes are as described above. When either the first or second electrode, or both, are transparent electrodes, the thickness of the transparent electrode is preferably 0.03 μm or more and 3 μm or less. When manufacturing solar cells, cutting may be performed between each process to form circuits. Examples of cutting may include mechanical patterning and laser patterning.

[0114] [Modularization Process] The elements with electrodes formed may be sealed. Examples of sealing methods include sealing with resin or sealing with a film containing resin. Examples of materials used for sealing include silazane, silicone rubber, resins having a siloxane skeleton, resins containing fluorine, and glass. Examples of sealing methods include coating, vapor deposition, or sealing by attaching a sheet. Furthermore, from the viewpoint of suppressing adhesion between elements that occurs when winding in a roll-to-roll manner, the surface of the sealed elements may be given a hairline finish.

[0115] [Step for forming the photoelectric conversion layer] The step for forming the photoelectric conversion layer may include a step of applying a liquid containing the photoelectric conversion layer material described above. Examples of application methods include spin coating, blade coating, slit die coating, screen printing, bar coating, mold making, print transfer, immersion and pull-up, inkjet, spray, and vacuum deposition.

[0116] From these options, a suitable choice is made depending on the characteristics of the photoelectric conversion layer to be fabricated, such as thickness control and orientation control. Annealing may be performed under reduced pressure or in an inert atmosphere (nitrogen or argon atmosphere) to remove the solvent or dispersion medium from the liquid containing the material of the applied photoelectric conversion layer.

[0117] The annealing temperature is preferably between 40°C and 300°C, and more preferably between 50°C and 150°C. Annealing is preferable because it can increase the contact area at the interface between the stacked layers, as the materials constituting each layer penetrate each other, thereby increasing the current.

[0118] [Step to form the charge transport layer] A preferred step for forming the charge transport layer is to apply a liquid containing the charge transport layer material described above. Examples of application methods include spin coating, blade coating, slit die coating, screen printing, bar coating, mold making, print transfer, immersion and pull-up, inkjet, spray, and vacuum deposition.

[0119] The contents of this disclosure will be described in more detail below using examples and comparative examples. This disclosure is not limited in any way by the following examples unless it exceeds the gist of the disclosure. In the following descriptions of examples, "parts" refers to mass unless otherwise specified.

[0120] <Preparation of Particle 1> Step (1) Under a nitrogen flow atmosphere, 5.46 parts of orthophthalonitrile and 45 parts of α-chloronaphthalene were added to a reaction vessel and heated to a temperature of 30°C, which was then maintained. Next, 3.75 parts of gallium trichloride were added at this temperature (30°C). The water concentration of the mixture at the time of addition was 150 ppm. After that, the temperature was raised to 200°C. Next, under a nitrogen flow atmosphere, the mixture was reacted at 200°C for 4.5 hours, then cooled, and the product was filtered when the temperature reached 150°C. The obtained filtrate was dispersed and washed with N,N-dimethylformamide at a temperature of 140°C for 2 hours, and then filtered. The obtained filtrate was washed with methanol and dried to obtain chlorogallium phthalocyanine particles in a yield of 71%.

[0121] Step (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, and while stirring, the mixture was dropped dropwise into 620 parts of ice water to reprecipitation, and then filtered under reduced pressure using a filter press. A No. 5C filter (manufactured by Advantec Co., Ltd.) was used at this time. 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 deionized water, and then the filtration using a filter press was repeated three times.

[0122] Finally, freeze-drying was performed to obtain hydroxygallium phthalocyanine particles (hydrated hydroxygallium phthalocyanine particles) with a solid content of 23% by mass in a yield of 71%. These hydroxygallium phthalocyanine particles were dried in a hyper-dry dryer (product name: HD-06R, frequency (oscillation frequency): 2455 MHz ± 15 MHz, manufactured by Nippon Biocon) to obtain hydroxygallium phthalocyanine (OHGaPc) particles (crystals) with a moisture content of 1.0% by mass or less.

[0123] Step (3) Five parts of the hydroxygallium phthalocyanine particles were mixed with five parts of N-methylformamide solvent. This mixture was dispersed for six hours using a sand mill (TSG-1 / 4G-4U, manufactured by Igarashi Machinery Manufacturing (now AIMEX), with a disc diameter of 70 mm and five discs) containing five glass beads, and then filtered and dried to obtain particle 1.

[0124] <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 by stirring for 24 hours to obtain Resin Solution 1.

[0125] (Example 1) The photoelectric element of Example 1 was obtained by the formation method described below. <Manufacturing of the photoelectric element> [Formation of the electron transport layer] An ITO-coated glass substrate was cleaned, and tin(II) oxide adjusted to 3% by mass was applied thereon by spin coating. Then, it was heated at 150°C for 30 minutes to form an electron transport layer on a thin film with a thickness of 15 nm.

[0126] [Formation of the photoelectric conversion layer] 22.4 mg of methylammonium bromide, 172 mg of formamidium iodide, and 576 mg of lead iodide were dissolved in 600 μL of N,N-dimethylformamide and 160 μL of dimethyl sulfoxide and stirred for 1 hour (Solution 1). Furthermore, 389.72 mg of cesium iodide was dissolved in 1000 μL of dimethyl sulfoxide and stirred for 1 hour (Solution 2). Then, 40 μL of the dissolved cesium iodide solution (Solution 2) was added to Solution 1 to prepare the photoelectric conversion layer coating solution. By spin-coating this coating solution onto the electron transport layer, Cs ０．０５ (FA ０．８３ MA ０．１７ ) ０．９６ Pb(I ０．９５ Br ０．０５ ) ３ A photoelectric conversion layer with a thickness of 500 nm was formed.

[0127] [Formation of the first charge transport layer] 0.1 g of the aforementioned particles, 0.01 g of a mixture of calixarene compounds (Japanese Patent Publication No. 2003-207913) represented by formulas (C-1) to (C-4), 0.01 g of trioctylmethylammonium-bis(trifluoromethanesulfonyl)imide, and 10.6 g of 2-propanol were mixed together. 11 g of zirconia beads were enclosed in this mixture, and the mixture was dispersed in a paint shaker (manufactured by Toyo Seiki) for 3 hours. The mass ratio of the calixarene compounds was set to the compound represented by formula (C-1): the compound represented by formula (C-2): the compound represented by formula (C-3): the compound represented by formula (C-4) = 1:1:1:1. Then, 0.2 g of resin solution 1 was added, and paint shaker dispersion was performed again for 4 hours. A charge transport layer with a thickness of 150 nm was formed by spin coating this charge transport layer solution onto the photoelectric conversion layer.

[0128] [Formation of the second charge transport layer] 0.15 g of Spiro-OMeTAD, used as the material for the second charge transport layer, was dissolved in 2.2 g of chlorobenzene. To this chlorobenzene solution, 60 μL of t-butylpyridine (TBP) was added to an acetonitrile solution obtained by dissolving 0.02 g of bis(trifluoromethanesulfonyl)imide silver in 0.3 g of acetonitrile and mixed. A coating solution for the second charge transport layer was prepared. This was applied to the above charge transport layer by spin coating to form a second charge transport layer with a thickness of 200 nm.

[0129] [Formation of Surface Modified Layer] 0.143 g of diphenyleneiodonium-bis(trifluoromethanesulfonyl)imide was mixed and dissolved with 1.1 g of monochlorobenzene to obtain a coating for the surface modified layer. A 1 nm surface modified layer was formed by spin-coating this coating onto the second charge transport layer.

[0130] [Formation of the first electrode] A layer with a thickness of 80 nm and an area of ​​0.09 cm² is formed on the second charge transport layer. ２ The gold electrodes were formed by vacuum deposition to obtain the photoelectric conversion element of Example 1.

[0131] [Analysis of Compound Amount] The electrode surface of the photoelectric conversion element was peeled off to expose the charge transport layer surface. This charge transport layer surface was wiped with a cotton swab soaked in solvent, dissolved in heavy DMSO, and measured by 1H-NMR (instrument: BRUKER, AVANCE3-500). The peeled charge transport layer components were also subjected to mass and structural analysis by elemental analysis such as GPC, MALDI-TOF-MS, IR, gas chromatography, XPS, and EDX to confirm the presence of compounds. The ASA of the charge transport layer components was calculated using the Python language and RDKit library after creating a Smiles structural formula. The film thickness was confirmed by cutting the photoelectric conversion element, fixing it on a tilted sample stage, and then using a cross-sectional SEM (instrument: Carl Zeiss GmbH, SmartSEM).

[0132] (Examples 2-6) The material type of the surface modification layer is changed to the material type shown in Table 2. Otherwise, the process is the same as in Example 1 to obtain the photoelectric conversion elements of Examples 2-6.

[0133] (Example 7) The particle size of particle 1 in the formation of the first charge transport layer is changed to 10 nm. Otherwise, the process is the same as in Example 1 to obtain the photoelectric conversion element of Example 7.

[0134] (Example 8) The particle size of particle 1 in the formation of the first charge transport layer is changed to 300 nm. Otherwise, the process is the same as in Example 1 to obtain the photoelectric conversion element of Example 8.

[0135] (Example 9) The photoelectric conversion element of Example 9 was obtained by fabricating in the same manner as in Example 1, except that a surface modification layer was not provided.

[0136] (Examples 10-26) In forming the first charge transport layer, the trioctylmethylammonium-bis(trifluoromethanesulfonyl)imide added as a compound to improve current density is changed to one of the compounds that improve current density shown in Table 2. Otherwise, the devices were prepared in the same manner as in Example 9 to obtain the photoelectric conversion elements of Examples 10-26. In Example 13, the compound that improves current density had the structure shown below.

[0137] (Example 27) The first charge transport layer was prepared in the same manner as in Example 9, except that the calixarene compound was changed to the addition of [C-1] alone, to obtain the photoelectric conversion element of Example 27.

[0138] (Example 28) The first charge transport layer was formed in the same manner as in Example 27, except that no compound was added to improve the current density, to obtain the photoelectric conversion element of Example 28.

[0139] (Example 29) The first charge transport layer was formed in the same manner as in Example 27, except that resin solution 1 was not added, to obtain the photoelectric conversion element of Example 29.

[0140] (Example 30) The first charge transport layer was formed in the same manner as in Example 27, except that the compound and resin solution 1 for improving current density were not added, to obtain the photoelectric conversion element of Example 29.

[0141] (Examples 31-34) In forming the first charge transport layer, the concentrations shown in Table 2 were changed by varying the amount of particle 1 added and the amount of calixarene compound added. In forming the second charge transport layer, the concentrations shown in Table 2 were changed by varying the amount of bis(trifluoromethanesulfonyl)imide silver added. Otherwise, the devices were prepared in the same manner as in Example 30 to obtain the photoelectric conversion elements of Examples 31-34.

[0142] (Examples 35-37) In forming the first charge transport layer, the concentrations shown in Table 2 were changed by varying the amount of particle 1 added, the amount of calixarene compound added, the amount of compound that improves current density added, and the amount of resin solution added. In forming the second charge transport layer, the concentrations shown in Table 2 were changed by varying the amount of bis(trifluoromethanesulfonyl)imide silver added. Otherwise, the devices were prepared in the same manner as in Example 27 to obtain the photoelectric conversion elements of Examples 35-37.

[0143] (Example 38) The first charge transport layer was formed in the same manner as in Example 1, except that the calixarene compound, the compound that improves current density, and the resin solution were not added, to obtain the photoelectric conversion element of Example 38.

[0144] (Example 39) The photoelectric conversion element of Example 39 was obtained by fabricating in the same manner as in Example 38, except that a surface modification layer was not provided.

[0145] (Example 40) The photoelectric conversion element of Example 40 was obtained by fabricating in the same manner as in Example 28, except that a calixarene compound was not added in the formation of the first charge transport layer.

[0146] (Example 41) The photoelectric conversion element of Example 41 was obtained by fabricating in the same manner as in Example 29, except that a calixarene compound was not added in the formation of the first charge transport layer.

[0147] (Examples 42-45) In forming the first charge transport layer, the concentration shown in Table 2 was changed by varying the amount of calixarene compound added. Otherwise, the process was the same as in Example 30 to obtain the photoelectric conversion elements of Examples 42-45.

[0148] (Example 46) The first charge transport layer was formed in the same manner as in Example 26, except that the compound and resin solution 1 for improving current density were not added, to obtain the photoelectric conversion element of Example 46.

[0149] (Example 47) In the formation of the first charge transport layer, the calixarene compound is changed to the addition of [C-9] shown in the following chemical formula. Otherwise, the device was prepared in the same manner as in Example 42 to obtain the photoelectric conversion element of Example 47.

[0150] (Example 48) The first charge transport layer was formed in the same manner as in Example 39, except that particle 1 was changed to [F-1] shown in the following chemical formula, to obtain the photoelectric conversion element of Example 48.

[0151] (Example 49) By omitting step (2) for the production of particle 1 and performing step (3) using the chlorogallium phthalocyanine produced in step (1), chlorogallium phthalocyanine particle 2 was produced. Then, in the formation of the first charge transport layer, the process was carried out in the same manner as in Example 39, except that particle 1 was replaced with chlorogallium phthalocyanine particle 2, to obtain the photoelectric conversion element of Example 49.

[0152] (Examples 50-52) The second charge transport layer was formed in the same manner as in Example 39, except that the charge transport material and dopant species were changed to the materials listed in Table 2, to obtain the photoelectric conversion elements of Examples 50-52.

[0153] (Example 53) The first charge transport layer was formed in the same manner as in Example 39, except that particle 1 was changed to the material shown in the following chemical formula, to obtain the photoelectric conversion element of Example 53.

[0154] (Examples 54, 55) The first charge transport layer was formed in the same manner as in Example 39, except that the particle 1 was changed to the material shown in Table 2, to obtain the photoelectric conversion elements of Examples 54 and 55.

[0155] (Comparative Example 1) A photoelectric conversion element for Comparative Example 1 was obtained by fabricating in the same manner as in Example 39, except that the first charge transport layer was not formed.

[0156] (Comparative Examples 2-5) The first charge transport layer was formed in the same manner as in Example 39, except that particle 1 was changed to the material shown in Table 2, to obtain the photoelectric conversion elements of Comparative Examples 2-5.

[0157] [Evaluation] (Evaluation of open-circuit voltage) A power supply (KEITHLEY, Model 236) was connected between the electrodes of the photoelectric conversion element in Example 1, and the intensity was 120 mW / cm. ２ Using a solar simulator (manufactured by Yamashita Densou Co., Ltd.), a constant amount of light was irradiated, and the initial photoelectric conversion efficiency was evaluated as the open-circuit voltage ratio by measuring the generated current and voltage. The results are shown in Table 3. The initial photoelectric conversion efficiency was evaluated in the same manner for the other examples and comparative examples. The measurement results for Example 1 were set to 100, and the relative values ​​are shown in Table 3 below.

[0158] (Durability Evaluation) The durability of the photoelectric conversion element in Example 1 was evaluated by continuously irradiating it with 10,000 Lx of light from a white LED and measuring the photoelectric conversion efficiency after 45 days. The photoelectric conversion efficiency after long-term use was evaluated as the maintenance rate of the photoelectric conversion efficiency after 45 days relative to the initial photoelectric conversion efficiency (maintenance rate in Table 3). The results are shown in Table 3. The other examples and comparative examples were evaluated in the same manner as in Example 1, and the photoelectric conversion efficiency after long-term use was evaluated as the maintenance rate of the photoelectric conversion efficiency after 45 days relative to the initial photoelectric conversion efficiency. The results are shown in Table 3.

[0159]

[0160] This disclosure is not limited to the embodiments described above, and various modifications and alterations are possible without departing from the spirit and scope of this disclosure. Accordingly, the following claims are attached to make the scope of this disclosure public.

[0161] This application claims priority based on Japanese Patent Application No. 2024-207470, filed on 28 November 2024, and Japanese Patent Application No. 2025-183853, filed on 30 October 2025, and all of the contents of those applications are incorporated herein by reference.

[0162] 1. Photoelectric element 2. Substrate 3. Second electrode 4. Electron transport layer 5. Photoelectric layer 6. Second charge transport layer 7. First electrode 8. First charge transport layer

Claims

1. A photoelectric element comprising a first electrode, a second electrode, and a photoelectric conversion layer containing a perovskite crystal disposed between the first electrode and the second electrode, wherein the photoelectric element has a first charge transport layer between the photoelectric conversion layer and the first electrode, a second charge transport layer between the first charge transport layer and the first electrode, the second charge transport layer contains a charge transport material and silver, and the first charge transport layer contains a cyclic conjugated compound in which a plurality of pyrrole rings having axial ligands are conjugated together.

2. The photoelectric conversion element according to claim 1, wherein the cyclic conjugated compound formed by the conjugation of a plurality of pyrrole rings having the axial ligand is a phthalocyanine compound.

3. The photoelectric conversion element according to claim 1 or 2, wherein the axial ligand is at least one selected from a halogen atom, an alkyl group, an aryl group, a carboxyl group, an alkoxy group, a hydroxyl group, a cyano group, an amino group, and an oxygen atom.

4. The photoelectric conversion element according to claim 2, wherein the axial ligand is one in the molecule of the phthalocyanine compound.

5. The photoelectric conversion element according to any one of claims 1 to 4, wherein the axial ligand is at least one selected from the group consisting of OH, Cl, and O.

6. The photoelectric conversion element according to claim 2, wherein the phthalocyanine compound is a hydroxygallium phthalocyanine compound.

7. The photoelectric element according to claim 2, 4, or 6, wherein the first charge transport layer comprises a calixarene compound.

8. The photoelectric conversion element according to claim 7, wherein the calixarene compound is represented by the following formula (A). (In the above formula (A), R ３１ ~R ３５ R is independent within each repeating unit and independently for each of the n repeating units. ３１ R represents a hydrogen atom or an alkyl group. ３２ R represents a substituted or unsubstituted alkylene group. ３３ ~R ３５ R 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. ３３ ~R ３５ At least one of these is a substituted -Y-Ar group. The -Y- represents -CH=N-, -CH=CH-, or -N=N-, and the Ar is a substituted or unsubstituted aromatic hydrocarbon group, or a substituted or unsubstituted heterocyclic group. n is an integer between 3 and 20.

9. The photoelectric conversion element according to claim 8, wherein n is 4 or 8.

10. The R ３４ is independently a nitrophenylazo group or a dinitrophenylazo group for each of n repeating units, and the photoelectric conversion element according to claim 8 or 9.

11. The photoelectric conversion element according to any one of claims 7 to 10, wherein the molecular weight of the calixarene compound is 10,000 or less.

12. The photoelectric conversion element according to any one of claims 7 to 11, wherein the calixarene compound is a mixture of the compound represented by the following formula (C-1), the compound represented by the following formula (C-2), the compound represented by the following formula (C-3), and the compound represented by the following formula (C-4).

13. The photoelectric element according to any one of claims 7 to 12, wherein the ratio of the mass of the calixarene compound to the mass of the phthalocyanine compound in the first charge transport layer is 0.002 times or more and 0.8 times or less.

14. The photoelectric conversion element according to any one of claims 1 to 13, wherein the first charge transport layer includes a compound that improves current density.

15. The photoelectric element according to any one of claims 1 to 14, wherein the first charge transport layer comprises an insulating resin.

16. The photoelectric conversion element according to any one of claims 1 to 15, further comprising a surface modification layer between the second charge transport layer and the first electrode.

17. The ratio of the mass concentration of silver in the second charge transport layer to the mass concentration of the phthalocyanine compound in the first charge transport layer is 0.4 × 10⁻⁶. －５ A photoelectric conversion element according to any one of claims 2, 4, or 6 to 13, wherein the conversion ratio is more than or equal to 17 times.

18. The ratio of the mass concentration of silver in the second charge transport layer to the mass concentration of the calixarene compound in the first charge transport layer is 0.9 × 10⁻⁶. －４ A photoelectric conversion element according to any one of claims 7 to 13, wherein the ratio is more than or equal to 8333 times.

19. A photoelectric conversion device having a photoelectric conversion element according to any one of claims 1 to 18.

20. A mobile body having a photoelectric conversion element according to any one of claims 1 to 18.

21. A building material having a photoelectric conversion element according to any one of claims 1 to 18.

22. A photoelectric element having a first electrode, a second electrode, and a photoelectric conversion layer containing a perovskite crystal disposed between the first electrode and the second electrode, wherein the photoelectric element has a charge transport layer between the photoelectric conversion layer and the first electrode, the region of the charge transport layer on the first electrode side contains a charge transport material and silver, and the region of the charge transport layer on the photoelectric conversion layer side contains a cyclic conjugated compound in which a plurality of pyrrole rings having axial ligands are conjugated together.

Images