Photoelectric conversion element for perovskite solar cell

Abstract

The present invention addresses the problem of providing: a passivating agent which is capable of further stabilizing a perovskite compound; a perovskite photoelectric conversion element which uses the passivating agent; and a perovskite solar cell.　The present invention relates to: a passivating agent for a perovskite compound, the passivating agent containing a tridentate cationic compound that has a triptycene skeleton; a perovskite photoelectric conversion element which has a perovskite compound that is passivated using the passivating agent; and a perovskite solar cell.

Description

Photoelectric conversion element for perovskite solar cells

[0001] The present invention relates to a photoelectric conversion element for a perovskite solar cell and a passivation agent used in the photoelectric conversion element.

[0002] ABX3 (A is a monovalent cation such as ammonium, and B is Pb 2+ Solar cells using compounds with a perovskite crystal structure (perovskite compounds) represented by a divalent metal cation (such as ZnO, ...

[0003] Perovskite-type compounds have a stability problem in that their crystal surfaces react easily with oxygen and moisture in the air. To overcome this instability, passivation agents for passivating perovskite-type compounds have been developed. Examples of passivation agents reported include phenylethylammonium, alkylammonium iodides, combinations of halogen bond donors and sulfur-containing compounds, and metal oxides such as Al2O3 and TiO2 (Patent Documents 1 to 3 and Non-Patent Document 1).

[0004] WO 2015 / 092397 WO 2018 / 007586 WO 2018 / 137048

[0005] J. Huang et al. , Adv. Mater. 2020,32,2000995

[0006] However, conventional passivators are not sufficient to stabilize the perovskite compounds in perovskite solar cells, and further improvements in photoelectric conversion efficiency are desired. Therefore, an object of the present invention is to provide a passivator that can further stabilize perovskite compounds, and a perovskite-based photoelectric conversion element and perovskite solar cell that use the same.

[0007] Therefore, the present inventors focused on triptycene compounds having three functional groups, synthesized a compound in which three cations were introduced into a triptycene compound, and found that when this compound was coated on the surface of a perovskite-type compound, the perovskite-type compound was stabilized and the photoelectric conversion efficiency of the photoelectric conversion element was significantly improved, thereby completing the present invention.

[0008] That is, the present invention provides the following inventions [1] to

[12] . [1] A passivator for a perovskite-type compound, containing a tridentate cationic compound having a triptycene skeleton. [2] The passivator according to [1], wherein the tridentate cationic compound having a triptycene skeleton is a triptycene compound having three ammonium groups. [3] The passivator according to [1] or [2], wherein the tridentate cationic compound having a triptycene skeleton is a compound represented by the following general formula (1):

[0009]

[0010] (In formula (1), R represents a hydrogen atom, a hydroxy group, an alkoxy group, a halogen atom, a cyano group, a carboxy group, or an alkoxycarbonyl group; Q represents a hydrogen atom or a halogen atom; Z represents an alkylene group or an oxyalkylene group which may have a substituent; X represents a halogen; and n represents an integer of 0 or 1.) [4] The passivator according to [3], wherein Z is an alkylene group or an oxyalkylene group. [5] The passivator according to [3] or [4], wherein Z is an alkylene group having 1 to 6 carbon atoms. [6] The passivator according to any of [3] to [5], wherein Z is a methylene group or an ethylene group. [7] The passivator according to any of [3] to [6], wherein n is 1. [8] The passivator according to any of [3] to [7], wherein R is a hydrogen atom. [9] A perovskite-type compound-containing photoelectric conversion layer having the passivator according to any one of [1] to [8] on the surface of a perovskite-type compound.

[10] A perovskite-type photoelectric conversion element having at least a first electrode, a hole transport layer, a perovskite-type compound-containing photoelectric conversion layer, an electron transport layer, and a second electrode, wherein the perovskite-type compound-containing photoelectric conversion layer is a photoelectric conversion layer having the passivator according to any one of [1] to [8] on the surface of a perovskite-type compound.

[11] A solar cell comprising the photoelectric conversion element according to

[10] .

[12] An optical sensor comprising the photoelectric conversion element according to

[10] .

[0011] A perovskite compound surface-treated with the passivating agent of the present invention is stably passivated, and a photoelectric conversion element comprising the surface-treated perovskite compound as a photoelectric conversion layer exhibits significantly improved photoelectric conversion efficiency. Therefore, a perovskite solar cell comprising this photoelectric conversion element is useful as a next-generation solar cell with improved photoelectric conversion efficiency.

[0012] 1 shows a schematic cross-sectional view of a perovskite-based photoelectric conversion element of the present invention. 2 shows a schematic diagram of an evaluation photoelectric conversion element used in the examples. 3 shows photoelectron yield spectroscopy spectra and ultraviolet-visible absorption spectra of Compound A and Compound B. (a): Photoelectron yield spectroscopy spectrum of Compound A, (b): Photoelectron yield spectroscopy spectrum of Compound B, (c): Ultraviolet-visible absorption spectrum of Compound A, (d): Ultraviolet-visible absorption spectrum of Compound B. 4 shows the fluorescence emission spectrum (PL) intensity of Element 1 (Compound A) and Element 3 (Control (solvent)). (a): Element 3, (b): Element 1. 5 shows the fluorescence decay curves (fluorescence lifetimes) of Element 1 (Compound A) and Element 3 (Control (solvent)). (a): Element 3, (b): Element 1. 6 shows the results of contact angle measurement of Element 1 (Compound A) and Element 3 (Control (solvent)). (a): Element 3, (b): Element 1. The current density-voltage (JV) curves of Device 1 (Compound A), Device 4 (Compound A), Device 2 (Compound B), and Device 5 (Compound B) are shown. (a) Device 1, (b) Device 4, (c) Device 2, and (d) Device 5. The solid line indicates the forward scan, and the dotted line indicates the reverse scan. This figure shows the stability (change over time) of the photoelectric conversion efficiency (PCE) of Device 4 (Compound A) and Device 5 (Compound B). (a): Device 4 (Compound A), (b): Device 5 (Compound B).

[0013] Unless otherwise specified, terms used in this specification are used in the sense commonly used in the relevant field. A solar cell is an electric power device that converts light energy into electrical energy by utilizing the photovoltaic effect. Materials that convert light energy into electrical energy include silicon-based compounds as well as InGaAs and other compounds. Recently, as mentioned above, the photoelectric conversion efficiency of perovskite compounds has increased, and therefore, the development of perovskite solar cells that use perovskite compounds as light-absorbing materials (photoelectric conversion materials) is progressing.

[0014] As mentioned above, perovskite compounds are compounds with a perovskite crystal structure represented by ABX3 (A is a monovalent cation, B is a divalent metal cation, and X is a halide ion). As A, alkylammonium cations and phenylammonium cations are widely known, but Cs +Monovalent metal ions such as Pb have also been reported. 2+ , Sn 2+ , Ge 2+ Divalent metal ions such as the above are known.

[0015] As mentioned above, a passivator is a component that inhibits the reaction of a perovskite compound with oxygen or moisture, thereby passivating the perovskite compound. It is known that the surface of a perovskite compound can be passivated by treating it with phenylethylammonium halide or the like, but the passivation effect is not sufficient.

[0016] One aspect of the present invention is a passivator for perovskite compounds, which contains a tridentate cationic compound having a triptycene skeleton. The tridentate cationic compound having a triptycene skeleton is a compound in which three cationic groups are substituted on three carbon atoms constituting the compound having a triptycene skeleton. Here, the triptycene skeleton is represented by the following formula:

[0017]

[0018] The cation substituted on the triptycene skeleton is an ammonium group (- + NH3). The ammonium group may be substituted directly onto a carbon atom of the triptycene skeleton, or may be substituted via an alkylene group or an oxyalkylene group. Specific examples of tridentate cationic compounds having a triptycene skeleton include compounds in which an ammonium group, an ammonium alkylene group, or an ammonium alkyleneoxy group is substituted onto three carbon atoms of the triptycene skeleton. Here, the alkylene group is preferably a linear or branched alkylene group having 1 to 6 carbon atoms, more preferably an alkylene group having 1 to 3 carbon atoms, and even more preferably a methylene group or an ethylene group. Here, the counter ion of the cation such as the ammonium group is preferably a halide ion such as an iodide ion, a bromide ion, or a chloride ion.

[0019] The tridentate cationic compound having a triptycene skeleton is preferably a compound represented by the following general formula (1).

[0020]

[0021] (In formula (1), R represents a hydrogen atom, a hydroxy group, an alkoxy group, a halogen atom, a cyano group, a carboxy group, or an alkoxycarbonyl group; Q represents a hydrogen atom or a halogen atom; Z represents an alkylene group or an oxyalkylene group which may have a substituent; X represents a halogen; and n represents an integer of 0 or 1.)

[0022] In formula (1), R represents a hydrogen atom, a hydroxy group, an alkoxy group, a halogen atom, a cyano group, a carboxy group, or an alkoxycarbonyl group. Here, the alkoxy group is preferably an alkoxy group having 1 to 6 carbon atoms, and more preferably an alkoxy group having 1 to 4 carbon atoms. Specific examples include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, and an n-butoxy group. Examples of halogen atoms include a bromine atom, a chlorine atom, a fluorine atom, and an iodine atom. Examples of alkoxycarbonyl groups include C1 to C6 alkoxycarbonyl groups, and preferred are C1 to C4 alkoxycarbonyl groups. Specific examples include a methoxycarbonyl group, an ethoxycarbonyl group, and an n-propyloxycarbonyl group. R is preferably a hydrogen atom, a hydroxy group, an alkoxy group, a halogen atom, or a cyano group, more preferably a hydrogen atom, an alkoxy group, or a halogen atom, and even more preferably a hydrogen atom.

[0023] Q represents a hydrogen atom or a halogen atom. Examples of the halogen atom include a bromine atom, a chlorine atom, a fluorine atom, and an iodine atom. Q is preferably a hydrogen atom.

[0024] Z represents an alkylene group or an oxyalkylene group, which may have a substituent. Examples of the substituent include a hydroxy group. Preferably, it is an alkylene group or an oxyalkylene group. As the alkylene group, a linear or branched alkylene group having 1 to 6 carbon atoms is preferred, a linear or branched alkylene group having 1 to 4 carbon atoms is more preferred, a linear or branched alkylene group having 1 to 3 carbon atoms is even more preferred, a methylene group or an ethylene group is even more preferred, and a methylene group is even more preferred. As the oxyalkylene group, a linear or branched oxyalkylene group having 1 to 6 carbon atoms is preferred, a linear or branched oxyalkylene group having 1 to 4 carbon atoms is more preferred, a linear or branched oxyalkylene group having 1 to 3 carbon atoms is even more preferred, and an oxymethylene group or an oxyethylene group is even more preferred.

[0025] X represents a halogen atom, such as a bromine atom, a chlorine atom, a fluorine atom, or an iodine atom.

[0026] n represents the number 0 or 1, and is more preferably 1.

[0027] Preferred specific examples of the tridentate cationic compound having a triptycene skeleton include 1,8,13-tri(ammoniomethyl)triptycene triiodide (compound A) and 1,8,13-triammoniotriptycene triiodide (compound B).

[0028] Tridentate cationic compounds having a triptycene skeleton can be produced, for example, by using trihydroxytriptycene as a starting material and converting the hydroxy group to an ammonium group, an ammonium alkylene group, or an ammonium alkyleneoxy group according to a conventional method. For example, 1,8,13-tri(ammoniomethyl)triptycene halide can be produced by reducing 1,8,13-tricyanotriptycene with a reducing agent such as lithium aluminum hydride to form 1,8,13-triaminotriptycene, followed by reaction with a hydrohalic acid such as hydroiodic acid. The reduction reaction can be carried out in a solvent such as tetrahydrofuran at a temperature between room temperature and the boiling point of the solvent for 5 to 30 hours. The ammonium conversion reaction with a hydrohalic acid can be carried out in a solvent such as ethanol at a temperature between 0°C and room temperature for several hours.

[0029] For example, 1,8,13-triammoniotriptycene trihalide can be produced by reacting 1,8,13-trihydroxytriptycene with 2-bromopropionylamide to convert the hydroxy group to a carbamoylethoxy group, then reacting this with an alkali hydroxide to form tri(2-hydroxypropionamido)triceptine through a rearrangement reaction, then hydrolyzing the amide bond with an acid such as hydrochloric acid to obtain 1,8,13-triaminotriptycene, and then reacting with a hydrohalic acid such as hydroiodic acid. The reaction of 1,8,13-trihydroxytriptycene with 2-bromopropionylamide can be carried out in a solvent such as dimethyl sulfoxide in the presence of a base such as potassium carbonate at room temperature to 100°C for 10 to 24 hours. The subsequent rearrangement reaction can be carried out in a solvent such as dimethyl sulfoxide with an alkali such as potassium hydroxide at 100°C to 200°C for 10 to 30 hours. The subsequent hydrolysis can be carried out by heating a strong acid such as concentrated hydrochloric acid in a solvent such as ethanol, while the subsequent ammonium reaction can be carried out by using a hydrohalic acid such as hydroiodic acid in a solvent such as ethanol at 0°C to room temperature for several hours.

[0030] When the surface of a perovskite compound layer is treated with a composition containing the tridentate cationic compound having a triptycene skeleton, the perovskite compound is stably passivated, and as a result, the photoelectric conversion efficiency of a photoelectric conversion element using the surface-treated perovskite compound as a photoelectric conversion layer is significantly improved. Therefore, the tridentate cationic compound having a triptycene skeleton is useful as a passivator for perovskite compounds, and the composition containing the tridentate cationic compound having a triptycene skeleton is useful as a passivator composition for perovskite compounds.

[0031] Such a passivator or passivator composition may contain, in addition to the tridentate cationic compound having a triptycene skeleton, various solvents, etc. The content of the tridentate cationic compound having a triptycene skeleton in the passivator or passivator composition is preferably 0.01% by mass or more and 90% by mass or less, and more preferably 0.1% by mass or more and 80% by mass or less, from the viewpoint of forming a sufficient amount of passivation layer on the surface of the perovskite compound. The solvent may be any solvent that can stably dissolve the tridentate cationic compound having a triptycene skeleton, and examples thereof include alcohols, preferably 2-propanol.

[0032] A composite layer having a passivation layer containing a tridentate cation compound having a triptycene skeleton formed on one or both sides of a perovskite compound layer is useful as a photoelectric conversion layer for a perovskite-based photoelectric conversion element. That is, one aspect of the present invention is a photoelectric conversion layer for a perovskite-based photoelectric conversion element having the passivation agent on the surface of a perovskite compound. From the viewpoint of achieving sufficient passivation effect, the passivation agent is preferably applied so as to form a passivation layer on at least 90% of the perovskite compound layer, more preferably at least 95%, and even more preferably at least 98%. Furthermore, the application method for the passivation agent may be any conventional coating method, such as spin coating, die coating, inkjet coating, or blade coating.

[0033] By using a photoelectric conversion layer having the passivator containing a tridentate cation compound having a triptycene skeleton on one or both sides of the perovskite compound layer, a photoelectric conversion element having stable and high photoelectric conversion efficiency can be obtained. That is, another aspect of the present invention is a perovskite-based photoelectric conversion element having at least a first electrode, a hole transport layer, a perovskite-based compound-containing photoelectric conversion layer, an electron transport layer, and a second electrode, wherein the perovskite-based compound-containing photoelectric conversion layer is a photoelectric conversion layer having the passivator on the surface of a perovskite compound.

[0034] A schematic cross-sectional view of a perovskite-based photoelectric conversion element of the present invention is shown in Figure 1. The perovskite-based photoelectric conversion element of the present invention has a first electrode 12, an electron transport layer 13, a perovskite-type compound-containing photoelectric conversion layer 14 (having a passivator layer 22 on the surface of a perovskite-type compound 21), a hole transport layer 15, and a second electrode 16. It also has a substrate 11 as needed.

[0035] In the photoelectric conversion element 1, when light is irradiated from the outside onto the photoelectric conversion layer 14, the photoelectric conversion layer 14 absorbs the light and generates electrons and holes. The electrons generated in the photoelectric conversion layer 14 are output to the outside through the first electrode 12, and the holes are output to the outside through the second electrode 16.

[0036] The substrate 11 serves to physically support the photoelectric conversion layer 14, the first electrode 12, and the second electrode 16. For example, a transparent material or a non-transparent material can be used for the substrate 11. Examples of transparent materials include glass and transmissive plastic. Examples of non-transparent materials include metal, ceramic, and non-transmissive plastic. When a transparent material is used for the substrate 11, sunlight that has passed through the substrate can be irradiated onto the photoelectric conversion layer to perform photoelectric conversion.

[0037] If either or both of the first electrode 12 and the second electrode 16 have sufficient strength, the substrate 11 can be omitted. In addition, although the substrate 11 is provided so as to be in contact with the first electrode 12 in Fig. 1, the substrate 12 may be provided so as to be in contact with the second electrode 16.

[0038] The first electrode 12 and the second electrode 16 can be made of a conductive material. Examples of conductive materials include metals, transparent metal oxides, and carbon materials. Examples of metals include gold, silver, copper, platinum, aluminum, titanium, nickel, tin, zinc, and chromium. Examples of transparent metal oxides include indium-tin composite oxide, antimony-doped tin oxide, fluorine-doped tin oxide, boron-doped, aluminum-doped, gallium-doped, and indium-doped zinc oxide. Examples of carbon materials include graphene, carbon nanotubes, and graphite.

[0039] It is desirable that either or both of the first electrode 12 and the second electrode 16 have optical transparency in the visible to near-infrared region. Even when a non-transparent material such as a metal or a carbon material is used for either the first electrode 12 or the second electrode 16, it is possible to provide optical transparency by providing a pattern for transmitting light. The pattern for transmitting light may have a lattice shape, a line shape, a wavy line shape, or the like.

[0040] When the first electrode 12 and the second electrode 16 are optically transparent, it is desirable that the transmittance be high. For example, it is 50% or more, and preferably 80% or more. Furthermore, it is desirable that the wavelength range of the transmitted light be a band wider than the absorption wavelength of the perovskite compound contained in the photoelectric conversion layer 14.

[0041] By providing the electron transport layer 13 between the photoelectric conversion layer 14 and the first electrode 12, the efficiency of extracting electrons from the first electrode 12 can be improved. The electron transport layer 13 is generally made of a semiconductor material. Examples of semiconductor materials used for the electron transport layer 13 include metal oxide materials and organic n-type semiconductor materials. Examples of metal oxide materials include titanium oxide, tin oxide, zinc oxide, and indium oxide. Examples of organic n-type semiconductor materials include imide compounds, quinone compounds, fullerenes, and derivatives thereof.

[0042] Furthermore, by providing a hole transport layer 15 between the photoelectric conversion layer 14 and the second electrode 16, the efficiency of extracting holes from the second electrode 16 can be improved. The hole transport layer 16 is generally made of a semiconductor material. Examples of semiconductor materials used for the hole transport layer 16 include inorganic p-type semiconductor materials and organic p-type semiconductor materials. Examples of inorganic p-type semiconductor materials include CuO, CuO, CuSCN, molybdenum oxide, and nickel oxide. Examples of organic p-type semiconductor materials include phenylamine and triphenylamine derivatives containing a tertiary amine in the skeleton, and PEDOT compounds containing a thiophene structure.

[0043] The photoelectric conversion element 1 can be manufactured by, for example, the following method. First, a first electrode 12 is formed on a substrate 11. The first electrode 12 can be formed by physical vapor deposition or chemical vapor deposition. Examples of physical vapor deposition include sputtering, resistance heating evaporation, and electron beam evaporation. Examples of chemical vapor deposition include thermal chemical vapor deposition, plasma enhanced chemical vapor deposition, and atomic layer deposition.

[0044] Next, the electron transport layer 13 is formed on the first electrode 12. The electron transport layer 13 can be formed by a known method such as a spray method, a spin coating method, or a sputtering method.

[0045] Next, the photoelectric conversion layer 14 is formed on the electron transport layer 13. The photoelectric conversion layer 14 may be formed by applying a liquid (coating liquid) containing a perovskite compound to form a perovskite compound layer, and then applying the passivator-containing liquid. Examples of the coating method include spin coating, die coating, inkjet coating, and blade coating.

[0046] Subsequently, a hole transport layer 15 and a second electrode 16 are formed on the photoelectric conversion layer 14. The hole transport layer 15 may be formed in the same manner as the electron transport layer 13, and the second electrode 16 may be formed in the same manner as the first electrode 12.

[0047] The obtained photoelectric conversion element has good stability and significantly improved photoelectric conversion efficiency, and therefore can be used in next-generation solar cells and photosensors. Therefore, another aspect of the present invention is a solar cell comprising the above-mentioned photoelectric conversion element. Also, another aspect of the present invention is a photosensor comprising the above-mentioned photoelectric conversion element.

[0048] The present invention will now be described in more detail with reference to examples, but the present invention is not limited to these examples.

[0049] (Nuclear Magnetic Resonance Spectrum (NMR) Measurement Method) The solid sample to be measured was dissolved in a deuterated solvent (CD3OD-d4 or DMSO-d6 manufactured by Kanto Chemical Co., Ltd.) and placed in an NMR tube (Wilmad NMR tubes 5 mm manufactured by Sigma-Aldrich Co.) to prepare a measurement sample. 1 H-NMR measurement conditions] Measurement device: NMR device AVANCE-400 manufactured by Bruker Measurement frequency: 400.0 MHz Measurement temperature: 25°C Base peak: CD3OD-d4: 1 H(δ)=3.31ppm, DMSO-d6: 1 H(δ)=2.50ppm [ 13 C NMR measurement conditions] Measurement device: NMR device AVANCE-500 manufactured by Bruker Measurement frequency: 125.7 MHz Measurement temperature: 25°C Base peak: CD3OD-d4: 13 C(δ)=39.52ppm DMSO-d6: 13 C(δ)=49.00ppm

[0050] (Infrared absorption spectrum (IR) measurement method) The solid sample to be measured was pulverized, diluted, and mixed with potassium bromide (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., for IR absorption measurement), and then molded into a disk shape using a pressure molding machine to obtain a measurement sample. [Measurement conditions] Measurement device: Fourier transform infrared spectrophotometer FT / IR-6600ST manufactured by JASCO Corporation Measurement wave number: 4000 to 400 cm -1

[0051] (Method for measuring ultraviolet-visible absorption spectrum (UV)) The solid sample to be measured was dissolved in methanol (for spectroscopic analysis, manufactured by Tokyo Chemical Industry Co., Ltd.), and then placed in a quartz cell for a spectrophotometer (manufactured by GL Sciences Co., Ltd.) to obtain a measurement sample. [Measurement conditions] Measurement device: UV-visible near-infrared spectrophotometer V-730 manufactured by JASCO Corporation Measurement wavelength: 200 to 400 nm

[0052] (Mass spectrometry) A solid sample was dissolved in methanol (manufactured by Kanto Chemical Co., Ltd.) to prepare a measurement sample. [Measurement conditions] Measurement device: Bruker time-of-flight mass spectrometer microTOF II Measurement method: atmospheric pressure chemical ionization (APCI) Measurement ion species: cation

[0053] (Photoelectron Yield Spectroscopy Measurement Method) A solid sample was used as a measurement sample, and -4 Measurement conditions: Measurement device: Ionization energy measurement device BIP-KV202GD manufactured by Bunkoukeiki Co., Ltd. Measurement energy: 4 to 7 eV

[0054] (Photoluminescence spectrum measurement) [Measurement conditions] Measurement device: FP-8300 fluorescence spectrophotometer manufactured by JASCO Corporation Measurement wavelength: 700 to 870 nm

[0055] (Fluorescence Lifetime Measurement) [Measurement Conditions] Measurement device: FluoroCube 3000U-UltraFast-SP spectrophotometer manufactured by Horiba, Ltd. Measurement excitation wavelength: λ ex =377nm Resolution: 50ps

[0056] (Contact angle measurement) [Measurement conditions] Measurement device: Contact angle meter CAME1 manufactured by Asumi Giken Co., Ltd.

[0057] (Perovskite solar cell evaluation method) [Current-voltage measurement conditions] Measurement device: DC voltage / current generator 6241A manufactured by ADC Corporation Light source: Solar simulator XES-301S manufactured by Sanei Corporation (AM1.5G sunlight 100 mW cm -2 ) [External quantum yield measurement conditions] Measurement device: SM-250 benchtop spectral response measurement device manufactured by Bunkoukeiki Co., Ltd. Attached source meter: Model 2401 manufactured by Keithley Instruments

[0058] (Production Example 1) 1,8,13-Tri(ammoniomethyl)triptycentriiodide (hereinafter referred to as Compound A) was synthesized based on the following synthesis scheme (which will be explained step by step below).

[0059]

[0060] 1,8,13-Tricyanotriptycene (compound 1) was synthesized according to a previous report (S. Das, et al., ACS Nano 2021, 15, 11168-11179).

[0061] (Synthesis of Compound 2) Under a nitrogen atmosphere and maintained at 0°C, lithium aluminum hydride (Kanto Chemical, 140 mg, 3.7 mmol) was dispersed in tetrahydrofuran (THF) (Kanto Chemical, 20 mL). Next, Compound 1 (200 mg, 0.61 mmol) was added to the dispersion and stirred for 30 minutes. Thereafter, a saturated aqueous solution (30 mL) of sodium potassium tartrate (Fujifilm Wako Pure Chemical Industries, Ltd.) was added dropwise to the suspension over 30 minutes. The resulting reaction mixture was extracted with dichloromethane, and the organic layer was washed three times with saturated saline. The solvent was removed from the washed organic layer under vacuum, and the mixture was dried under vacuum to obtain Compound 2 as a white solid. The yield was 97%. NMR measurement and mass analysis were performed on Compound 2 using the methods described above. The spectral data for Compound 2 are shown below. 1 H NMR (400MHz, DMSO-d6, 25°C): δ (ppm) 7.30 (d, J = 6.8Hz, 3H), 6.98-6.90 (m, 6H), 6.64 (s, 1H), 5.57 (s, 1H), 4.07 (s, 6H). 13 C NMR (126 MHz, DMSO-d6, 25°C): δ (ppm) 146.61, 143.44, 138.11, 125.43, 124.88, 122.51, 53,82, 43.74, 41.29. APCI-TOF-MS (positive mode): calcd. forC 23 H 23 N3: m / z=342.1965; found: 342.2000. FT-IR(KBr)ν(cm -1) 3419, 3044, 2954, 2924, 1635, 1577, 1507, 1469, 1433, 1381, 1328, 1309, 1261, 1195, 1158, 1086, 1058, 1020, 996, 919, 801, 768, 723, 701.

[0062] (Synthesis of Compound A) Under a nitrogen atmosphere, Compound 2 (130 mg, 0.38 mmol) was dissolved in ethanol (3 mL), and the resulting solution was cooled to 0°C. Hydroiodic acid (Kanto Chemical Co., Inc., concentration: 57% by mass, 7.2 mL) was slowly added dropwise to the solution, and the mixture was stirred at 0°C for 3 hours. Diethyl ether was added to the reaction solution, and a yellow precipitate was formed. The resulting precipitate was filtered and dried in vacuo at 60°C to obtain Compound A as a yellow solid. The yield was 62%. NMR and IR measurements of Compound A were performed using the methods described above. The spectral data of Compound A are shown below. 1 H NMR (500MHz, CD3OD-d4, 25°C): δ (ppm) 7.54 (d, J = 6.5Hz, 3H), 7.22-7.17 (m, 6H), 6.56 (s, 1H), 5.76 (s, 1H), 4.78 (s, 6H). 13 C NMR (126 MHz, CD3OD-d4, 25°C): δ (ppm) 148.13, 143.85, 130.04, 127.65, 126.85, 125.72, 55.763, 43.560, 41.955. FT-IR (KBr): ν (cm -1 ) 3446, 3014, 2926, 2690, 2591, 1622, 1589, 1558, 1541, 1489, 1458, 1435, 1388, 1200, 1161, 1109, 1067, 1032, 801, 770, 720. Anal. Calcd for C 23 H 26 N3I3: C, 38.09; H, 3.61; N, 5.79; I, 52.50. Found: C, 37.94; H, 3.82; N, 5.67.

[0063] (Production Example 2) 1,8,13-Triammoniotriptycentreiodide (hereinafter referred to as Compound B) was produced based on the following synthesis scheme, which will be explained in order below.

[0064]

[0065] 1,8,13-Trihydroxytriptycene (3) was synthesized by the method previously reported (N. Seiki, et al., Science 2015, 348, 1122-1126.).

[0066] (Synthesis of Compound 4) Under a nitrogen atmosphere, compound 3 (2.0 g, 6.6 mmol), 2-bromopropionylamide (Merck, 6.0 g, 40 mmol), and potassium carbonate (Fujifilm Wako Pure Chemical Industries, Ltd., 8.2 g, 59 mmol) were dissolved in 55 mL of dimethyl sulfoxide (DMSO) (Kanto Chemical Co., Ltd.), the temperature was raised to 80°C, and the mixture was stirred for 20 hours. The reaction solution was cooled to room temperature and poured into water, resulting in the formation of a white precipitate. The resulting precipitate was filtered, washed with water, and vacuum dried to obtain compound 4. NMR measurement of compound 4 was performed using the method described above, and the NMR spectrum data of compound 4 is shown below. 1 H NMR (400MHz, DMSO-d6, 25°C): δ (ppm) 7.55-7.32 (m, 6H), 7.12-7.09 (m, 3H), 6.95-6.91 (m , 3H), 6.75-6.61 (m, 4H), 6.68-5.63-5.61 (m, 1H), 4.67-4.58 (m, 3H), 1.57-1.50 (m, 9H).

[0067] (Synthesis of Compound 6) Under a nitrogen atmosphere, compound 4 (3.0 g, 5.8 mmol) and potassium hydroxide (Fujifilm Wako Pure Chemical Industries, Ltd.) (1.6 g, 29 mmol) were dissolved in DMSO (55 mL) and stirred at 150°C for 24 hours. The reaction solution was cooled to 25°C, dispersed in water, and then extracted with ethyl acetate. The organic layer was dried over anhydrous sodium sulfate, and the solvent was removed under vacuum. The resulting solid was dried under vacuum at 60°C to obtain compound 5. Compound 5 was dissolved in ethanol (120 mL), and hydrochloric acid (concentration: 35% by mass, 50 mL) and water (30 mL) were added to this solution, followed by heating under reflux for 16 hours. The reaction solution was cooled to room temperature, diluted with water, and neutralized with saturated aqueous sodium bicarbonate solution. The resulting aqueous layer was extracted with ethyl acetate, and the organic layer was washed with water and saturated brine. The organic layer was dried over anhydrous sodium sulfate, and the solvent was removed under vacuum. The obtained solid was recrystallized with ethyl acetate to obtain Compound 6 as a white solid in a yield of 46%. Compound 6 was subjected to NMR, IR and mass spectrometry by the methods described above. 1 H and 13 The C NMR spectrum is shown below. 1 H NMR (400MHz, DMSO-d6, 25°C): δ (ppm) 6.62-6.57 (m, 6H), 6.26 (d, J=7.0Hz, 3H), 6.06 (s, 1H), 5.20 (s, 6H), 5.09 (s, 1H). 13 C NMR (126 MHz, DMSO-d6, 25°C): δ (ppm) 147.76, 142.73, 128.87, 125.06, 112.50, 112.01, 54.966, 34.891. FT-IR(KBr)ν(cm -1 ) 3425, 2958, 2929, 1542, 1479, 1445, 1339, 1294, 1254, 1181, 938, 862, 795, 729, 681, 516. APCI-TOF-MS (positive mode): calcd. forC 20 H 17 N3: m / z=300.1495; found:300.1504.

[0068] (Synthesis of Compound B) Under a nitrogen atmosphere, Compound 6 (100 mg, 0.33 mmol) was dissolved in ethanol (2 mL) and cooled to 0°C. Hydroiodic acid (concentration: 57% by mass, 5 mL) was slowly added to the solution, and the mixture was stirred at 0°C for 3 hours. Diethyl ether was added to the reaction solution, and a yellow precipitate was formed. The resulting precipitate was filtered and dried in vacuo at 60°C to obtain Compound B as a yellow solid in a yield of 43%. NMR and IR measurements were performed on Compound B using the methods described above, and the 1 H and 13 The C NMR spectrum is shown below. 1 H NMR (400MHz, DMSO-d6, 25°C): δ (ppm) 7.17 (d, J = 7.6Hz, 3H), 6.97 (d d, J=7.6Hz, 3H), 6.76 (d, J=7.6Hz, 3H), 6.18 (s, 1H), 5.63 (s, 1H). 13 C NMR (126 MHz, DMSO-d6, 25°C): δ (ppm) 147.80, 134.23, 132.28, 127.24, 121.19, 118.52, 53.143, 37.135. FT-IR(KBr)ν(cm -1 ) 3567, 3419, 2876, 2552, 1597, 1558, 1542, 1507, 1474, 1444, 1238, 1200, 1173, 1162, 1081, 792, 761, 722. Anal. Calcd for C 20 H 20 N3I3: C, 35.17; H, 2.95; N, 6.15; I, 55.73. Found: C, 34.84; H, 3.11; N, 6.37.

[0069] The molecular structures of 1,8,13-tri(ammoniomethyl)triptycentreiodide (compound A) and 1,8,13-triammoniotriptycentreiodide (compound B) are shown below.

[0070]

[0071] Photoelectron yield spectroscopy and ultraviolet absorption spectroscopy were performed under the above conditions. The measurement results are shown in Figure 3. Based on the photoelectron yield spectroscopy and absorption spectroscopy measurements, deep HOMO levels (-5.99 eV) and wide band gaps (>3.8 eV) were obtained for Compound A and Compound B. These results indicated that thin films prepared using Compound A and Compound B may function as passivators rather than hole transport layers.

[0072] (Fabrication of Perovskite Solar Cells) Fluorine-doped tin oxide (FTO) transparent conductive glass (Sigma-Aldrich, surface resistance 7 Ω) was used as the substrate. The FTO layer on the substrate was etched using masking tape with 6 M hydrochloric acid and metallic zinc (Zn, Fujifilm Wako Pure Chemical Industries, Ltd.). The FTO layer was then washed sequentially with detergent, acetone, isopropyl alcohol, and deionized water. A compact TiO layer (hereinafter referred to as the cTiO layer) was then deposited on the FTO layer by spray pyrolysis of an ethanol solution (1:14 v / v) of titanium diisopropoxide bis(acetylacetonate) (Tokyo Chemical Industry Co., Ltd.) at 450 °C. A TiO2 paste (PST-30NR-D, GreatCell Solar Ltd.) diluted with ethanol (paste:ethanol = 1:7 w / w) was spin-coated onto the cTiO2 layer (ramp 3 seconds, 5,000 rpm, 15 seconds, ramp 2 seconds), and then baked at 500 °C for 20 minutes to deposit a 200 nm-thick mesoporous TiO2 layer (hereinafter referred to as mpTiO2 layer) (average particle size: 30 nm, anatase). Next, a 1.4 M solution of formamidine hydroiodide ((NH)CHI, manufactured by Tokyo Chemical Industry Co., Ltd., hereafter referred to as FAI), lead iodide (PbI, manufactured by Tokyo Chemical Industry Co., Ltd.), methylammonium bromide (CHNHBr, manufactured by Tokyo Chemical Industry Co., Ltd., hereafter referred to as MABr), and lead bromide (PbBr, manufactured by Tokyo Chemical Industry Co., Ltd.) in a 4:1 (v / v) mixture of N,N'-dimethylformamide (DMF, ultra-dehydrated, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.):dimethyl sulfoxide (DMSO, ultra-dehydrated, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was mixed in a nitrogen-filled glove box at a stoichiometric ratio (MABr:PbBr:FAI:PbI = 0.13:0.13:0.87:0.87) to prepare a perovskite precursor solution.

[0073] The perovskite precursor solution was then spin-coated onto the mpTiO layer to form a precursor layer (1-second ramp, 10-second ramp at 1000 rpm, 4-second ramp, 30-second ramp at 4500 rpm, 2-second ramp). After 35 seconds, 180 μL of anhydrous chlorobenzene 99.8% (Sigma-Aldrich) was slowly dripped onto the precursor layer on the rotating substrate as a poor solvent treatment. The resulting transparent film was then heat-treated at 100°C for 40 minutes, converting the precursor layer to the perovskite compound and forming a 300 nm-thick perovskite layer.

[0074] The passivation layer was formed on the perovskite layer by spin-casting an isopropyl alcohol solution (0.5 to 3.0 mg / mL) containing tridentate cation compounds having a triptycene skeleton (compounds A and B) at 5000 rpm for 15 seconds.

[0075] The hole transport agent layer is formed on the passivation layer or the perovskite layer by dissolving a hole transport material, Spiro-OMeTAD (manufactured by Borun New Material Technology Ltd.), in acetonitrile (manufactured by Sigma-Aldrich, anhydrous, 99.8%), 2.9% by volume of 4-tert-butylpyridine (TBP, Sigma-Aldrich, 98%) relative to the amount of the solution, 52 mol% of (trifluoromethanesulfonyl)imide (hereinafter, LiTFSI, manufactured by Tokyo Chemical Industry Co., Ltd.) and Co(TFSI)2 (FK209, manufactured by Lumtec) relative to the amount of Spiro-OMeTAD. A 50 nm-thick Spiro-OMeTAD thin film was fabricated by spin-coating a solution (concentration: 78.2 mg / mL) of chlorobenzene (Sigma-Aldrich, anhydrous, 99.8%) containing 5.4 mol% of chlorobenzene (Sigma-Aldrich, Inc.). A 70 nm-thick striped gold electrode was then thermally evaporated in a vacuum chamber. To promote oxygen doping into the hole transport agent layer, the device was then stored in an oxygen-purged desiccator in a dark place for 3 days, and used as a photoelectric conversion device for evaluation (Figure 2).

[0076] Example 1 (Study on the use of thin films prepared using Compound A and Compound B as passivation layers) Composition formula: MA 0.13 FA 0.87 PbI2.61 Br 0.39 A passivation layer was prepared by spin-coating an isopropyl alcohol (IPA) solution of Compound A onto a binary mixed perovskite (hereinafter referred to as PVK) consisting of [MABr (or PbBr2):FAI (or PbI2) = 0.13:0.87]. The concentration of Compound A in the IPA solution was 1.0 mg / mL. The obtained photoelectric conversion element is hereinafter referred to as element 1.

[0077] Example 2 A passivation layer was produced in the same manner as in Example 1, except that Compound B was used instead of Compound A. The obtained photoelectric conversion element is hereinafter referred to as Element 2.

[0078] Comparative Example 1 To compare the effect of the passivation layer, a control sample was prepared by spin-coating only IPA onto the PVK.

[0079] 4 shows the fluorescence emission spectra measured by the above method for the devices 1 and 3. The fluorescence emission (PL) intensity observed for the device 3 (solvent only) was almost the same as that before the passivation layer was applied (FIG. 4(a)). The fluorescence emission (PL) intensity observed for the device 1 using compound A was 1.49 times that before the passivation layer was applied (FIG. 4(b)).

[0080] Figure 5 shows the fluorescence lifetimes measured by the above method for Devices 1 and 3. Device 1, which used Compound A, showed an improved average lifetime compared to Device 3, which did not have a passivation layer. The results of all PL decays and biexponential analysis are shown in Table 1. These results indicate that Compound A, which has a flexible ammoniomethyl moiety, coordinates to the A-site vacancies on the PVK film surface and can therefore efficiently passivate defects at the PVK interface.

[0081]

[0082] (Contact Angle Measurement) The contact angles of the elements 1 and 3 were measured by the method described above. The results are shown in Fig. 6. Fig. 6(a) shows the results for element 3 (solvent only), and Fig. 6(b) shows the results for element 1. After the application of the passivation layer, the contact angle of element 1 using compound A was approximately the same as that of element 3.

[0083] Example 3 A passivation layer was produced in the same manner as in Example 1, except that the concentration of Compound A in the IPA solution was changed to 1.5 mg / mL. The obtained photoelectric conversion element is hereinafter referred to as element 4.

[0084] Example 4 A passivation layer was produced in the same manner as in Example 3, except that Compound B was used instead of Compound A. The obtained photoelectric conversion element is hereinafter referred to as Element 5.

[0085] Example 5

[0086] (Evaluation of perovskite solar cells) The current-voltage curve was obtained by irradiating AM1.5G sunlight at 100 mWcm from a 300 W solar simulator (Sanei Corporation, XES-301S). -2 The active region was irradiated with 1 sun (monitored by a calibrated standard cell, Bunko Keiki BS-520BK) and measured using a light source-voltmeter unit (ADCMT Corporation, 6241A). The size of the active region was measured by a square hole (2 × 2 mm 2 The wavelength was defined by a black metal mask with a hole in the center. The external quantum efficiency (EQE) spectra were measured using a Bunko Keiki model SM-250KD equipped with a Keithley model 2401 light source meter. The monochromatic light power was calibrated using a silicon photocell (Bunko Keiki model S1337-1010BQ).

[0087] Figure 7 shows the current density-voltage (JV) curves for a perovskite solar cell (PSC) [composition: fluorine-doped tin oxide (FTO) / compact TiO2 / mpTiO2 / PVK (with / without passivation layer) / Spiro-OMeTAD / Au] (see Figure 2). The results showed that the power conversion efficiency (PCE) of the PSC passivated with Compound A was 20.25%, superior to the control (18.92%) and the PSC passivated with Compound B (18.92%). As shown in Table 2, the passivation layer prepared using a 1.5 mg / mL solution was optimal. The hysteresis was slightly larger for the PSC passivated with Compound A than for the control, resulting in similar average PCE values ​​for both [control: 17.38 ± 1.10%; Compound B: 17.37 ± 0.99%]. The improvement in open-circuit voltage (VOC) and fill factor (FF) by passivation with Compound A is a significant passivation effect, consistent with the PL measurements. The short-circuit current density (JSC) values ​​remained almost unchanged.

[0088]

[0089] The results of the PSC stability evaluation are shown in Figure 8. The elements were stored in air at a temperature of 23°C and a relative humidity of 75%. It was found that elements 1 and 4, which were treated using compound A as a passivation layer, had higher stability than those before the passivation layer was applied. Similarly, element 2, which was treated using compound B, had the same stability as before the passivation layer was applied. In contrast, element 5, which had an increased solution concentration of compound B applied during spin coating, showed improved stability.

[0090] REFERENCE SIGNS LIST 1 Photoelectric conversion element 11 Substrate 12 First electrode 13 Electron transport layer 14 Photoelectric conversion layer 15 Hole transport layer 16 Second electrode 21 Perovskite compound 22 Passivation layer

Claims

1. A passivator for perovskite-type compounds, containing a tricationic compound having a triphenylene skeleton.

2. The passivator according to claim 1, wherein the tricationic compound having a triphenylene skeleton is a triphenylene compound having three ammonium groups.

3. The passivating agent according to claim 1, wherein the trivalent cationic compound having a triphenylene skeleton is a compound represented by the following general formula (1). (In formula (1), R represents a hydrogen atom, a hydroxy group, an alkoxy group, a halogen atom, a cyano group, a carboxy group or an alkoxycarbonyl group; Q represents a hydrogen atom or a halogen atom; Z represents an alkylene group or an oxyalkylene group which may have a substituent; X represents a halogen; and n represents an integer of 0 or 1.) 4. The passivator according to claim 3, wherein Z is an alkylene group or an oxyalkylene group.

5. The passivator according to claim 3, wherein Z is an alkylene group having 1 to 6 carbon atoms.

6. The passivator according to claim 3, wherein Z is a methylene group or an ethylene group.

7. The passivator according to claim 3, wherein n is 1.

8. The passivator according to claim 3, wherein R is a hydrogen atom.

9. A photoelectric conversion layer of a perovskite-based photoelectric conversion device, having the passivator according to any one of claims 1 to 8 on the surface of a perovskite-type compound.

10. A perovskite-based photoelectric conversion device having at least a first electrode, a hole transport layer, a perovskite-type compound-containing photoelectric conversion layer, an electron transport layer, and a second electrode, wherein the perovskite-type compound-containing photoelectric conversion layer is a photoelectric conversion layer having the passivator according to any one of claims 1 to 8 on the surface of a perovskite-type compound.

11. A solar cell comprising the photoelectric conversion device according to claim 10.

12. An optical sensor comprising the photoelectric conversion device according to claim 10.

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