Photoelectric conversion element, photoelectric conversion apparatus, photoelectric conversion system, 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) which is disposed between the first electrode (7) and the second electrode (3) and contains crystals of a perovskite structure. The photoelectric conversion element (1) comprises a first charge transport layer (8) between the photoelectric conversion layer (5) and the first electrode (7), and a second charge transport layer (6) 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 calixarene compound having the structure represented by formula (A).

Description

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

[0001] This disclosure relates to photoelectric conversion elements, photoelectric conversion devices, photoelectric conversion systems, 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 hole transport layer contains a compound having a phthalocyanine skeleton. Patent Document 2 also 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. 2017 / 018529

[0007] According to the inventors' examination of the present disclosure, while the photoelectric conversion elements described in Patent Documents 1 and 2 show an effect in improving the initial photoelectric conversion efficiency, they exhibit hysteresis in the current density-voltage characteristics (I-V characteristics) where the curve differs in the sweep direction, posing a challenge to the reproducibility of the photoelectric conversion efficiency.

[0008] Therefore, the object of this disclosure is to provide a photoelectric conversion element that can stably extract power by improving the hysteresis of the current density-voltage characteristics (I-V characteristics). Furthermore, the object of this disclosure is to provide a photoelectric conversion device that can stably extract power by improving the hysteresis of the current density-voltage characteristics (I-V characteristics).

[0009] The above objectives are achieved by the present disclosure below. Specifically, the present disclosure relates to a photoelectric 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 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 calixarene compound having a structure 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 having 1 to 4 carbon atoms. ３２ R represents a substituted or unsubstituted alkylene group having 1 to 3 carbon atoms. ３３ ~R ３５ R represents a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, a substituted or unsubstituted -Y-Ar group, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 16 carbon atoms, or a substituted or unsubstituted heterocyclic group having 2 to 16 carbon atoms. ３３ ~R ３５Among them, at least one is a -Y-Ar group having a substituent. The -Y- represents -CH=N-, -CH=CH-, or -N=N-, and the Ar is a substituted or unsubstituted aromatic hydrocarbon group having 6 to 16 carbon atoms or a substituted or unsubstituted heterocyclic group having 2 to 16 carbon atoms. n is an integer of 3 or more and 20 or less. ) Further, the present disclosure relates to a photoelectric conversion device having the above photoelectric conversion element. Further, the present disclosure relates to a moving body having the above photoelectric conversion element. Further, the present disclosure relates to a building material having the above photoelectric conversion element. Further, 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 charge transport layer between the photoelectric conversion layer and the first electrode, a region on the first electrode side of the charge transport layer contains a charge transport material and silver, and a region on the photoelectric conversion layer side of the charge transport layer contains a calixarene compound having a structure represented by the following formula (A). (In the above formula (A), R ３１ ~R ３５ are each independently within each repeating unit and each independently for every n repeating units, R ３１ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R ３２ represents a substituted or unsubstituted alkylene group having 1 to 3 carbon atoms, R ３３ ~R ３５ represent a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, a substituted or unsubstituted -Y-Ar group, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 16 carbon atoms, or a substituted or unsubstituted heterocyclic group having 2 to 16 carbon atoms, and R ３３ ~R ３５Of these, at least one 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 having 6 to 16 carbon atoms, or a substituted or unsubstituted heterocyclic group having 2 to 16 carbon atoms. n is an integer between 3 and 20. Furthermore, this disclosure relates to a photoelectric conversion system in which a photoelectric conversion element and a control device for increasing or decreasing the voltage of the photoelectric conversion element are connected, wherein the photoelectric conversion element has 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 calixarene compound having a structure 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 having 1 to 4 carbon atoms. ３２ R represents a substituted or unsubstituted alkylene group having 1 to 3 carbon atoms. ３３ ~R ３５ R represents a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, a substituted or unsubstituted -Y-Ar group, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 16 carbon atoms, or a substituted or unsubstituted heterocyclic group having 2 to 16 carbon atoms. ３３ ~R ３５ Of these, at least one 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 having 6 to 16 carbon atoms, or a substituted or unsubstituted heterocyclic group having 2 to 16 carbon atoms. n is an integer between 3 and 20.

[0010] According to this disclosure, it is possible to provide a photoelectric conversion element, a photoelectric conversion device, and a photoelectric conversion system that can stably extract power.

[0011] 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 perspective view showing one embodiment of a mobile body equipped with the photoelectric conversion element of the present disclosure. This is a schematic perspective view showing one embodiment of a building material equipped with the photoelectric conversion element of the present disclosure.

[0012] <Embodiments> An embodiment of the present disclosure of a photoelectric conversion element and a composition is described below. 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 calixarene compound having a structure 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 having 1 to 4 carbon atoms. ３２ R represents a substituted or unsubstituted alkylene group having 1 to 3 carbon atoms. ３３ ~R ３５ R represents a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, a substituted or unsubstituted -Y-Ar group, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 16 carbon atoms, or a substituted or unsubstituted heterocyclic group having 2 to 16 carbon atoms. 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 having 6 to 16 carbon atoms, or a substituted or unsubstituted heterocyclic group having 2 to 16 carbon atoms. n is an integer between 3 and 20.) The explanation follows below.

[0013] As a result of their investigation, the inventors of this disclosure have found that having the first and second charge transport layers described above improves the hysteresis of the current density-voltage characteristics (I-V characteristics), enabling stable power extraction. Although the details of why such high effectiveness is achieved in this disclosure are not clear, it is thought to be as follows.

[0014] When measuring the current density-voltage characteristics (I-V characteristics), normally, at open-circuit voltage, holes generated in the photoelectric conversion layer cannot move to the charge transport layer, and no current flows. However, as the voltage is gradually reduced, holes gradually move to the charge transport layer, and current begins to flow. As the voltage is further reduced, the number of holes passing through the charge transport layer increases, eventually resulting in a short-circuit current and the current reaching its maximum. However, if silver ions, which have a larger ionic radius than lithium ions, which are commonly used as dopants, are present in the charge transport layer, the holes will move through the charge transport layer while avoiding the silver ions with the same polarity and larger ionic radius due to electrostatic repulsion.

[0015] When the voltage is increased in reverse from a short-circuit state, the number of holes moving from the photoelectric conversion layer to the charge transport layer decreases, and the current also decreases. When the open-circuit voltage is reached, the holes can no longer move to the charge transport layer, and the current stops flowing again. However, if silver ions are present in the charge transport layer, the large number of holes that have moved to the charge transport layer due to the short-circuit current are blocked by the silver ions, and electrostatic repulsion between the large number of holes is also added, causing a congestion of holes and restricting their movement. As a result, even at the same voltage as when stepping down, the current is lower when stepping up, and it is hypothesized that the hysteresis of the current density-voltage characteristic (I-V characteristic) becomes larger.

[0016] On the other hand, in this configuration, the first charge transport layer contains a calixarene compound having the structure shown in formula (A). It is believed that this calixarene compound traps silver ions floating in the second charge transport layer at the interface between the first and second charge transport layers, thereby facilitating the movement of holes in the second charge transport layer and improving the hysteresis of the current density-voltage characteristics (I-V characteristics).

[0017] Calixarene compounds having the structure shown in formula (A) possess two electron sources: the π electrons of the aromatic ring and the lone pair of electrons on the oxygen atom. We believe that by utilizing these, silver ions can be firmly trapped in two different modes: the formation of a π complex with silver ions and electrostatic interactions.

[0018] The photoelectric conversion element of the present 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, wherein there is 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.

[0019] [First Charge Transport Layer] The photoelectric conversion element of the present disclosure includes a first charge transport layer comprising a calixarene compound having the structure shown in formula (A). By including a calixarene compound having the structure shown in formula (A), the hysteresis of the current density-voltage characteristics (I-V characteristics) is improved as described above, and power can be extracted stably. (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 having 1 to 4 carbon atoms. ３２ R represents a substituted or unsubstituted alkylene group having 1 to 3 carbon atoms. ３３ ~R ３５ R represents a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, a substituted or unsubstituted -Y-Ar group, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 16 carbon atoms, or a substituted or unsubstituted heterocyclic group having 2 to 16 carbon atoms. ３３ ~R ３５ Of these, at least one 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 having 6 to 16 carbon atoms, or a substituted or unsubstituted heterocyclic group having 2 to 16 carbon atoms. n is an integer between 3 and 20.

[0020] The above R ３１ and R３３ ~R ３５ 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.

[0021] 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.

[0022] Also, R ３３ ~R ３５ Examples of substituents that alkyl groups, -Y-Ar 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.

[0023] Furthermore, in this disclosure, R in formula (A) ３４ However, it is preferable that for each of the n repeating units, independently, the -Y- is -N=N-, and for each of the n repeating units, independently, the -Y- is a nitrophenylazo group or a dinitrophenylazo group.

[0024] Calixarene compounds containing -N=N- have a large moment of charge imbalance due to the sterically protruding -N=N- group. This charge imbalance strengthens the electrostatic interaction force, allowing for more robust trapping of silver ions. Furthermore, if the -Y- group is a nitrophenylazo group or a dinitrophenylazo group, the effect of this electrostatic interaction is further enhanced.

[0025] Furthermore, in this disclosure, R ３１ However, it is preferable that each of the n repeating units is independently a hydrogen atom 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 is independently a methylene group, an ethylene group, or a propylene group. ３３ , R ３５ However, it is preferable that it be a hydrogen atom.

[0026] In this disclosure, it is preferable that n in formula (A) is 4 to 8 for trapping silver ions with a large ionic radius. Furthermore, in this 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.

[0027] In this disclosure, it is preferable 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).

[0028] In this disclosure, it is preferable that the first charge transport layer contains a cyclic conjugated compound in which a plurality of pyrrole rings are conjugated together. The cyclic conjugated compound, in which a plurality of pyrrole rings are covalently bonded together, has a planar structure in which a 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.

[0029] The cyclic conjugated compound, which consists of multiple pyrrole rings conjugated together, preferably has a particle size of 10 nm to 300 nm. If the particle size is within the above range, the penetration of the cyclic conjugated compound into other layers can be suppressed, and the uniformity of the film can be maintained, thereby suppressing the loss of hole transport.

[0030] The particle size of a cyclic conjugated compound, which consists of multiple pyrrole rings conjugated together, can be altered by dispersing the first charge transport layer solution in a paint shaker. The particle size can be reduced by increasing the dispersion time. Furthermore, the particle size can be further reduced by centrifuging the charge transport layer solution.

[0031] Furthermore, in this disclosure, it is preferable that the cyclic conjugated compound, which is formed by the conjugation of multiple pyrrole rings, has an axial ligand. This cyclic conjugated compound can form complexes with various elements at the center of the ring, and the axial ligand can be positioned in the vertical direction of the plane of the cyclic conjugated compound. In this disclosure, it is preferable that there is one axial ligand in one molecule of the cyclic conjugated compound, which is formed by the conjugation of multiple pyrrole rings.

[0032] In this disclosure, cyclic conjugated compounds formed by the covalent bonding of multiple pyrrole rings 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. In particular, in this disclosure, from the viewpoint of charge transport ability, the cyclic conjugated compound formed by the conjugated bonding of multiple pyrrole rings is more preferably a phthalocyanine compound.

[0033] Specific examples of porphyrin compounds are listed below.

[0034] R １ ~R １２Each 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, phenylthio groups, tert-butyl groups, hydroxyl groups, carbonyl groups, methoxy groups, amino groups, sulfo groups, and aldehyde groups are preferred.

[0035] 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 If there are a total of four of these, the crystallinity tends to be low and the solubility tends to be high. X represents a metal atom, and Y represents an axial ligand, which will be described in detail later.

[0036] Specific examples of phthalocyanine compounds are listed below.

[0037] R １３ ~R ２８Each of these independently represents an organic group containing a hydrogen atom, an aromatic group which may have substituents, or an aliphatic group which may have substituents. 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, phenylthio groups, tert-butyl groups, hydroxyl groups, carbonyl groups, methoxy groups, amino groups, sulfo groups, and aldehyde groups are preferred.

[0038] 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 １５ , R １９ , R ２３ , R ２７ If there are a total of four of these, the crystallinity tends to be low and the solubility tends to be high. X represents a metal atom, and Y represents an axial ligand, which will be described in detail later.

[0039] Cyclic conjugated compounds, formed by the conjugation of multiple pyrrole rings, have a central element for possessing an axial ligand, represented by X in formulas (P-1) and (P-2). While various elements can be the central element, Ga, Ti, V, Al, In, Fe, Si, Sn, and Mn are preferred due to their high charge transport capacity. Among these, Ga is particularly preferred from the viewpoint of charge transport capacity.

[0040] In this 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. In particular, from the viewpoint of charge transport ability, it is more preferable that the axial ligand is at least one selected from the group consisting of hydroxyl groups, chloro groups, and oxygen atoms. From the above viewpoint, in this disclosure, it is more preferable that the phthalocyanine compound is a hydroxygallium phthalocyanine compound.

[0041] In this disclosure, it is preferable that the first charge transport layer contains a compound that improves the current density. Furthermore, it is preferable that the compound that improves the current density is 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)). 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.

[0042] 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.

[0043] 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. Furthermore, the SP value and functional groups of the resin can be appropriately selected to suppress the formation of voids. 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.

[0044] In the photoelectric conversion element disclosed herein, 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.

[0045] 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 order to efficiently trap silver.

[0046] Furthermore, in this disclosure, it is preferable that the ratio of the mass of the cyclic conjugated compound, in which a plurality of pyrrole rings are conjugated together, to the mass of the resin is 5 or more and 30 or less, in that the charge transport capacity in the charge transport layer can be further improved.

[0047] 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.

[0048] The thickness of the first charge transport layer is preferably 5 nm to 800 nm. If the thickness is 5 nm or more, even if silver ions cannot be trapped at the interface between the first and second charge transport layers, they can be trapped in the first charge transport layer, preventing further migration of silver ions. If the thickness is 800 nm or less, it is easier to transfer the charge to the second charge transport layer. More preferably, the thickness 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 capacity at the interface can also be expected.

[0049] [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.

[0050] 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-OMeTAD, PTAA, and phthalocyanine compounds are preferred. The charge transport material may be a polymer or not.

[0051] In this disclosure, the second charge transport layer contains a compound that improves the current density. The compound that improves the 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)).

[0052] Examples of anions include the following:

[0053] The above-mentioned anion is contained as an ionic compound bonded to a charge transport material cation. The silver contained in the second charge transport layer preferably exists as a counter-cation of the above-mentioned anion. This is because it has a large ionic radius and is effective in improving the initial photoelectric conversion efficiency.

[0054] The second charge transport layer, like the first 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. Furthermore, the SP value and functional groups of the resin can be appropriately selected to suppress the formation of voids.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] In this disclosure, it is preferable that the ratio of the concentration (mass%) of silver in the second charge transport layer to the concentration (mass%) of the calixarene compound in the first charge transport layer is 0.045 to 3.6 times. By keeping it within this range, the improvement of the hysteresis of the current density-voltage characteristics (I-V characteristics) due to the above mechanism can be effectively achieved.

[0059] In this disclosure, it is preferable that the ratio of the concentration (mass%) of silver in the second charge transport layer to the concentration (mass%) of a cyclic conjugated compound formed by the conjugation of a plurality of pyrrole rings having axial ligands in the first charge transport layer is 0.0090 times or more and 0.11 times or less. In this disclosure, it is preferable that the ratio of the concentration (mass%) of silver in the second charge transport layer to the concentration (mass%) of the phthalocyanine compound in the first charge transport layer is 0.0090 times or more and 0.11 times or less.

[0060] The first charge transport layer and the second charge transport layer may be integrated (in which case, the integrated unit is also simply referred to as the "charge transport layer" in this disclosure). In this case, the disclosure relates to 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 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 calixarene compound having a structure represented by 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 having 1 to 4 carbon atoms. ３２ R represents a substituted or unsubstituted alkylene group having 1 to 3 carbon atoms. ３３ ~R ３５ R represents a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, a substituted or unsubstituted -Y-Ar group, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 16 carbon atoms, or a substituted or unsubstituted heterocyclic group having 2 to 16 carbon atoms. ３３ ~R ３５Of these, at least one 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 having 6 to 16 carbon atoms, or a substituted or unsubstituted heterocyclic group having 2 to 16 carbon atoms. n is an integer between 3 and 20.

[0061] [Surface Modification Layer] The photoelectric conversion element of the present disclosure preferably has a surface modification layer between the photoelectric conversion layer and the first 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.

[0062] By having a surface modification layer between the photoelectric conversion layer and the first charge transport layer, charge can be efficiently transferred from the photoelectric conversion layer to the first charge transport layer. Furthermore, by appropriately configuring the wettability and interface states with the surface modification layer, charge can be transferred even more efficiently, thereby improving the photoelectric conversion efficiency.

[0063] [Supplement based on Rule 26 04.02.2026] Examples of the passivation materials include the following:

[0064] Examples of ionic liquid materials include imidazolium salts, pyrrolidinium salts, pyridinium salts, piperidinium salts, ammonium salts, phosphonium salts, sulfonium salts, and iodonium salts as cations of the ionic liquid material. Examples of anions are as follows:

[0065] 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, the thickness is 0.1 nm or more and 20 nm or less.

[0066] As described above, the effects of this disclosure can be achieved through the synergistic interactions of each component.

[0067] The present disclosure will be described in detail below with reference to preferred embodiments. The present disclosure is not limited to the embodiments described below, and modifications and improvements made to the embodiments described below, based on the ordinary knowledge of those skilled in the art, are also included in the scope of the present disclosure, without departing from the spirit of the present disclosure. In this specification, "layer" means not only layers with clear boundaries or flat, thin films, but also layers with a concentration gradient in which the contained elements change gradually, and layers that can form a complex, interwoven structure together with other layers. Furthermore, layer analysis can be performed, for example, by cutting and peeling off each layer, and then performing mass and structural analysis of the components of each peeled layer using MALDI-TOF-MS / XPS / IR / gas chromatography, etc., to confirm the presence of compounds.

[0068] 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. 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 the second electrode 3, an electron transport layer 4, a photoelectric conversion layer 5, the first charge transport layer 8, the second charge transport layer 6, and the 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.

[0069] 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. The electron transport layer 4 is a layer placed between the photoelectric conversion layer 5 and the two electrodes (the second electrode 3 and the 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, a photoelectric conversion element may be fabricated on the substrate 2 in the order of 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.

[0070] 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.

[0071] 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, applying it in the desired order, and drying it. These film formation methods can be selected according to the requirements of each layer. Each layer will be described below.

[0072] [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.

[0073] [Electrodes] The materials of the first electrode 7 and the second electrode 3 are not particularly limited, and conventionally known materials can be used. Examples include 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 / Al2O3 mixtures, and Al / LiF mixtures.

[0074] 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.

[0075] 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.

[0076] [Photoelectric Conversion Layer] The photoelectric conversion layer 5 has a perovskite crystal structure. The perovskite crystal structure used in this disclosure is preferably represented by the following general formula [1]. A ｏ B ｐ Z ｑ [1] (In the above general formula [1], A is a cation, B is a cation, and Z is an anion. Also, o, p, and q satisfy 0 < o ≤ 10, 0 < p ≤ 10, and 0 < q ≤ 20, respectively, and A, B, and Z may be composed of a single material or two or more types may be used in combination. Additives may be added within the range in which the above general formula holds.)

[0077] Crystals with the composition represented by the above general formula [1] generally form a three-dimensional perovskite crystal. However, if the constituent cation A is too large 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 photoelectric conversion layers.

[0078] 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.

[0079] 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.

[0080] 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.

[0081] 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.

[0082] In the general formula [1] above, Z is a halogen or a 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 crystals of the perovskite structure are likely to be soluble in organic solvents, and it becomes possible to apply them to inexpensive printing methods and the like. Therefore, halogen atoms are preferred. Furthermore, iodine is more preferred because the energy band gap of the crystals of the perovskite structure becomes narrower.

[0083] Specifically, the three-dimensional perovskite, two-dimensional perovskite, and mixed three-dimensional / two-dimensional perovskite include 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<e000216>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.

[0084] 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.

[0085]

[0086] 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.

[0087] The perovskite crystal used in this disclosure 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.

[0088] The thickness of the photoelectric conversion layer according to 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.

[0089] [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.

[0090] 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.

[0091] 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.

[0092] [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.

[0093] 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.

[0094] 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.

[0095] 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.

[0096] <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.

[0097] 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.

[0098] [Photoelectric Conversion System] The photoelectric conversion system of the present disclosure is a photoelectric conversion system in which a photoelectric conversion element and a control device for increasing or decreasing the voltage of the photoelectric conversion element are connected, wherein the photoelectric conversion element has 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 calixarene compound having a structure 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 having 1 to 4 carbon atoms. ３２ R represents a substituted or unsubstituted alkylene group having 1 to 3 carbon atoms. ３３ ~R ３５ R represents a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, a substituted or unsubstituted -Y-Ar group, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 16 carbon atoms, or a substituted or unsubstituted heterocyclic group having 2 to 16 carbon atoms. ３３ ~R ３５At 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 having 6 to 16 carbon atoms, or a substituted or unsubstituted heterocyclic group having 2 to 16 carbon atoms. n is an integer between 3 and 20.) That is, the photoelectric conversion system of the present disclosure has a photoelectric conversion element of the present disclosure.

[0099] Thus, in order to efficiently generate power using a photoelectric converter, a control device that increases or decreases the voltage of the photoelectric converter may be connected to the photoelectric converter. As a control device, for example, MPPT (Maximum Power Tracking) control can be used. MPPT control is a control method that increases or decreases the voltage of the photoelectric converter by simulating a change in load resistance, and searches for and tracks the point where the output power is maximum (maximum power point).

[0100] When increasing or decreasing the voltage of a photoelectric conversion element using MPPT control, if the hysteresis of the current density-voltage characteristic (I-V characteristic) is large, a large difference in output power will occur between boosting and bucking the voltage, even at the same voltage, making it impossible to stably track the maximum power point. On the other hand, the photoelectric conversion element disclosed in this disclosure has a small hysteresis in the current density-voltage characteristic (I-V characteristic), so even if the voltage increases or decreases, the difference in output power is small if the voltage remains the same. Therefore, MPPT control can function effectively and generate power stably at the maximum power. Explanations of the other items are as described above and will be omitted.

[0101] [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.

[0102] 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.

[0103] [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.

[0104] 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.

[0105] 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. Exteriors 44a and 44b may be made 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.

[0106] 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.

[0107] <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.

[0108] [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. Furthermore, when manufacturing solar cells, cutting may be performed between each process to form circuits. Examples of cutting may include mechanical patterning and laser patterning.

[0109] [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.

[0110] 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.

[0111] 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.

[0112] [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.

[0113] [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.

[0114] The present disclosure will be described in more detail below using examples and comparative examples. The present disclosure is not limited in any way by the following examples unless it exceeds the gist of the disclosure. In the following examples, "parts" refers to mass unless otherwise specified.

[0115] <Preparation of Hydroxygallium Phthalocyanine Particles> 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%.

[0116] 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.

[0117] 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) crystals with a moisture content of 1.0% by mass or less.

[0118] Step (3) Five parts of the hydroxygallium phthalocyanine crystals 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 hydroxygallium phthalocyanine particles.

[0119] <Preparation of Resin Solution 1> 1.0 g of polyvinyl acetal resin (product name: BM-2, manufactured by Sekisui Chemical Co., Ltd., glass transition temperature 71°C) was dissolved in 19 g of 2-propanol with stirring for 24 hours to obtain Resin Solution 1.

[0120] (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.

[0121] [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.

[0122] [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 photoelectric conversion layer.

[0123] [Formation of the first charge transport layer] 0.1 g of hydroxygallium phthalocyanine particles, 0.01 g of a mixture of calixarene compounds represented by formulas (C-1) to (C-4) as described above (Japanese Patent Publication No. 2003-207913), 0.01 g of trioctylmethylammonium-bis(trifluoromethanesulfonyl)imide, and 10.6 g of 2-propanol were mixed. 11 g of zirconia beads were enclosed in this mixture, and dispersion was performed in a paint shaker (manufactured by Toyo Seiki) for 3 hours. The mass ratio of the calixarene compounds was set to compound (C-1): compound (C-2): compound (C-3): compound (C-4) = 1:1:1:1. The particle size of the hydroxygallium phthalocyanine particles was 100 nm.

[0124] Subsequently, 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.

[0125] [Formation of the second charge transport layer] 0.15 g of Spiro-OMeTAD was dissolved in 2.2 g of chlorobenzene as the material for the second charge transport layer. To this chlorobenzene solution, 0.05 g of an acetonitrile solution obtained by dissolving 0.2 g of bis(trifluoromethanesulfonyl)imide silver in 0.3 g of acetonitrile and 60 μL of t-butylpyridine (TBP) were added and mixed. A coating solution for the second charge transport layer was prepared. This was applied to the first charge transport layer by spin coating to form a second charge transport layer with a thickness of 200 nm.

[0126] [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. ２The gold electrodes were formed by vacuum deposition to obtain the photoelectric conversion element of Example 1.

[0127] (Evaluation of I-V characteristics) Light irradiation area: 0.09 cm² ２ The photoelectric conversion element obtained was masked in such a manner. A xenon lamp white light was used as the light source (Pexel Technologies, PEC-L01), and the light intensity (100 mW / cm²) was equivalent to sunlight (AM 1.5). ２ The current density-voltage characteristics (I-V characteristics) were measured using an I-V characteristic measuring device (PECK2400-N, manufactured by Pexel Technologies). Other conditions were: scanning speed 0.1 V / sec (0.01 V step), waiting time after voltage setting 50 msec, measurement integration time 20 msec, and the voltage was stepped down from 1.2 V to -0.1 V, then stepped up to 1.2 V to complete the measurement.

[0128] The area inside the I-V curves obtained during both voltage bucking and voltage boosting was calculated, and these areas were substituted into the following formula to calculate the hysteresis index. A larger hysteresis index indicates smaller hysteresis. Hysteresis Index (%) = (Area inside the I-V curve during voltage boosting) / (Area inside the I-V curve during voltage bucking) × 100

[0129] (Evaluation of photoelectric conversion efficiency) A power supply (KEITHLEY, Model 236) was connected between the electrodes of the obtained photoelectric conversion element, and the light intensity was set to 100 mW / cm². ２ The photoelectric conversion efficiency was evaluated by irradiating a constant amount of light using a solar simulator (manufactured by Yamashita Densou Co., Ltd.) and measuring the generated current and voltage.

[0130] (Examples 2-41) Using the compound represented by formula (C-1) to the compound represented by formula (C-4) and the compound represented by formula (C-5) to the compound represented by formula (C-9) below, the materials shown in Tables 2-5 are used to fabricate photoelectric conversion elements in the same manner as in Example 1, at the concentrations shown in Tables 2-5. The obtained photoelectric conversion elements are evaluated in the same manner as in Example 1. The results are shown in Table 8.

[0131] (Comparative Example 1) A photoelectric conversion element was fabricated in the same manner as in Example 1, using the materials shown in Tables 6 and 7 at the concentrations shown in Tables 6 and 7, except that the first charge transport layer was not formed. The obtained photoelectric conversion element was evaluated in the same manner as in Example 1. The results are shown in Table 8.

[0132] (Comparative Example 2) Photoelectric conversion elements were fabricated in the same manner as in Example 1, using the materials shown in Tables 6 and 7 at the concentrations shown in Tables 6 and 7. The obtained photoelectric conversion elements were evaluated in the same manner as in Example 1. The results are shown in Table 8.

[0133] [Supplement based on Rule 26, 04.02.2026]

[0134] [Supplement based on Rule 26, 04.02.2026]

[0135] [Supplement based on Rule 26, 04.02.2026]

[0136] [Supplement based on Rule 26, 04.02.2026]

[0137] [Supplement based on Rule 26, 04.02.2026]

[0138] [Supplement based on Rule 26, 04.02.2026]

[0139] [Supplement based on Rule 26, 04.02.2026]

[0140] [Supplement based on Rule 26, 04.02.2026]

[0141]

[0142] 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.

[0143] This application claims priority based on Japanese Patent Application No. 2024-207471 filed on 28 November 2024, Japanese Patent Application No. 2025-014347 filed on 30 January 2025, and Japanese Patent Application No. 2025-183919 filed on 30 October 2025, and all of the contents of those applications are incorporated herein by reference.

[0144] 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 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 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 calixarene compound having a structure represented by 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 having 1 to 4 carbon atoms. ３２ R represents a substituted or unsubstituted alkylene group having 1 to 3 carbon atoms. ３３ ~R ３５ R represents a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, a substituted or unsubstituted -Y-Ar group, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 16 carbon atoms, or a substituted or unsubstituted heterocyclic group having 2 to 16 carbon atoms. ３３ ~R ３５ Of these, at least one 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 having 6 to 16 carbon atoms, or a substituted or unsubstituted heterocyclic group having 2 to 16 carbon atoms. n is an integer between 3 and 20.

2. The photoelectric conversion element according to claim 1, wherein n is 4 to 8.

3. The photoelectric conversion element according to claim 1 or 2, wherein -Y- is -N = N-.

4. The photoelectric conversion element according to any one of claims 1 to 3, wherein each of the n repeating units is independently a nitrophenylazo group or a dinitrophenylazo group.

5. The photoelectric conversion element according to any one of claims 1 to 4, wherein the molecular weight of the calixarene compound is 10,000 or less.

6. The photoelectric conversion element according to any one of claims 1 to 5, 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).

7. The photoelectric element according to any one of claims 1 to 6, wherein the first charge transport layer includes a cyclic conjugated compound in which a plurality of pyrrole rings are conjugated together.

8. The photoelectric conversion element according to claim 7, wherein the cyclic conjugated compound formed by the conjugation bonding of the plurality of pyrrole rings has an axial ligand.

9. The photoelectric element according to claim 8, wherein the axial ligand of the cyclic conjugated compound formed by the conjugation of the plurality of pyrrole rings is one per molecule of the cyclic conjugated compound formed by the conjugation of the plurality of pyrrole rings.

10. The photoelectric conversion element according to any one of claims 7 to 9, wherein the cyclic conjugated compound formed by the conjugation of the plurality of pyrrole rings is a phthalocyanine compound.

11. The photoelectric conversion element according to claim 8 or 9, 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.

12. The photoelectric conversion element according to claim 11, wherein the axial ligand is at least one selected from the group consisting of a hydroxyl group, a chloro group, and an oxygen atom.

13. The photoelectric conversion element according to claim 10, wherein the phthalocyanine compound is a hydroxygallium phthalocyanine compound.

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

17. The photoelectric conversion element according to any one of claims 1 to 16, wherein the ratio of the concentration (mass%) of silver in the second charge transport layer to the concentration (mass%) of the calixarene compound in the first charge transport layer is 0.045 times or more and 3.6 times or less.

18. The photoelectric element according to claim 10 or 13, wherein the ratio of the concentration (mass%) of silver in the second charge transport layer to the concentration (mass%) of the phthalocyanine compound in the first charge transport layer is 0.0090 times or more and 0.11 times or less.

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 conversion element having a first electrode, a second electrode, and a photoelectric conversion layer containing a perovskite-structured 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, a region on the first electrode side of the charge transport layer contains a charge transport material and silver, and a region on the photoelectric conversion layer side of the charge transport layer contains a calixarene compound having a structure represented by the following formula (A). A photoelectric conversion element characterized by the above. (In the above formula (A), R ３１ ~R ３５ are each independently within each repeating unit and each independently for every n repeating units, R ３１ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R ３２ represents a substituted or unsubstituted alkylene group having 1 to 3 carbon atoms, R ３３ ~R ３５ represent a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, a substituted or unsubstituted -Y-Ar group, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 16 carbon atoms, or a substituted or unsubstituted heterocyclic group having 2 to 16 carbon atoms, and at least one of R ３３ ~R ３５ is a -Y-Ar group having a substituent. The -Y- represents -CH=N-, -CH=CH-, or -N=N-, and the Ar is a substituted or unsubstituted aromatic hydrocarbon group having 6 to 16 carbon atoms or a substituted or unsubstituted heterocyclic group having 2 to 16 carbon atoms. n is an integer of 3 or more and 20 or less.) 23. A photoelectric conversion system comprising a photoelectric conversion element and a control device for increasing or decreasing the voltage of the photoelectric conversion element, wherein the photoelectric conversion element comprises 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 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 calixarene compound having a structure 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 having 1 to 4 carbon atoms. ３２ R represents a substituted or unsubstituted alkylene group having 1 to 3 carbon atoms. ３３ ~R ３５ R represents a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, a substituted or unsubstituted -Y-Ar group, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 16 carbon atoms, or a substituted or unsubstituted heterocyclic group having 2 to 16 carbon atoms. ３３ ~R ３５ Of these, at least one 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 having 6 to 16 carbon atoms, or a substituted or unsubstituted heterocyclic group having 2 to 16 carbon atoms. n is an integer between 3 and 20.

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