Perovskite precursor solution and preparation method therefor

Abstract

A perovskite precursor solution according to one embodiment of the present disclosure comprises a halide precursor, Sn ions, Ni as a reducing agent, and a solvent, and the Sn ions can include Sn2+ and Sn4+.

Description

Perovskite precursor solution and method for preparing the same

[0001] The present disclosure relates to a perovskite precursor solution and a method for preparing the same.

[0002] The need to develop environmentally friendly and sustainable energy technologies to address climate change is growing. Photovoltaic devices encompass both photovoltaic and electro-optical conversion devices. Solar cells, one type of photovoltaic device, are attracting attention as a sustainable energy technology and a solution that can proactively meet future energy demands. Solar cells are the fundamental unit of solar power generation and are semiconductor devices that convert solar energy into electrical energy, utilizing the photovoltaic effect.

[0003] However, current solar cell technology is not efficient enough to meet future energy demands, necessitating technological innovations that surpass current standards. To address this, innovative materials-based technologies such as dye-sensitized solar cells, organic solar cells, quantum dot solar cells, and perovskite solar cells (PSCs) have been developed as next-generation solar cells.

[0004] Among them, perovskite solar cells have emerged as one of the thin-film solar cells to replace conventional silicon solar cells. Perovskite solar cells, which include hole transport materials, light absorbing materials, and electron transport materials, exhibit remarkably high photovoltaic effects by using perovskite materials as light absorbing materials. In relation to this, a method for manufacturing perovskite solar cells using a halide perovskite precursor solution containing Sn has been proposed. However, since Sn is unstable when existing as a divalent ion, when used in halide perovskite, Sn 4+ There is a problem that it is easily oxidized.

[0005] Attempts have been made to use Sn powder as a reducing agent, but membrane filters are required to remove Sn powder from the precursor solution. However, the pressure generated during the filtration process can cause small Sn powder particles to pass through the membrane filter and remain in the solution. Remaining Sn powder adheres to the surface of the perovskite thin film during fabrication, hindering crystal growth and interfering with the operation of the solar cell device.

[0006] Some embodiments of the present disclosure provide a method for preparing Sn present in a perovskite precursor solution using Ni as a reducing agent. 4+ A method can be proposed to reduce the amount of Ni and reuse the remaining Ni in the solution without a filtering process.

[0007] Some embodiments of the present disclosure can improve the efficiency and stability of Sn-based perovskite solar cell devices, and can reuse reducing agents without a separate filtration process.

[0008] A perovskite precursor solution according to one embodiment of the present disclosure comprises a halide precursor, Sn ions, a reducing agent Ni, and a solvent, wherein the Sn ions are Sn 2+ and Sn 4+ may include.

[0009] In one embodiment, the reducing agent Ni is Sn 4+ Sn 2+ can be reduced to

[0010] In one embodiment, the solvent may comprise at least one of DMF and DMSO.

[0011] In one embodiment, the halide precursor may comprise an organic halide.

[0012] In one embodiment, the organic halide may include at least one of methylammonium (MA), formamidinium (FA), or a combination thereof.

[0013] In one embodiment, the reducing agent Ni can be removed from the perovskite precursor solution by magnetic force.

[0014] A method for preparing a perovskite precursor solution according to one embodiment of the present disclosure may include the steps of preparing a container containing a perovskite precursor solution including Sn ions, adding a reducing agent Ni to the perovskite precursor solution, applying a magnetic force to the perovskite precursor solution, and discharging the perovskite precursor solution excluding the reducing agent Ni from the container.

[0015] In one embodiment, the Sn ion is Sn 2+ and Sn 4+ may include.

[0016] In one embodiment, the reducing agent Ni is Sn 4+ Sn 2+ can be reduced to

[0017] A perovskite photonic device can be manufactured using a perovskite precursor solution according to one embodiment.

[0018] According to various embodiments of the present disclosure, Sn present in a perovskite precursor solution is prepared by using Ni as a reducing agent. 4+ We propose a method to reduce the amount of Ni and reuse the remaining Ni in the solution without a filtering process.

[0019] According to various embodiments of the present disclosure, the efficiency and stability of a Sn-based perovskite solar cell device can be improved, and the reducing agent can be reused without a separate filtration process.

[0020] The effects of the present disclosure are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims.

[0021] Figure 1 shows the oxidized Sn by adding Ni to the Sn-based perovskite precursor solution used in the present invention. 4+Schematic diagram of the process of reducing Ni and reusing it without filtering it out.

[0022] Figure 2 is a schematic diagram showing a method for filtering Sn and Ni metals.

[0023] Figure 3 shows XRD patterns of a perovskite thin film fabricated with a precursor solution using Ni and a perovskite thin film fabricated without using a reducing agent.

[0024] Figure 4 shows an SEM image of a perovskite thin film without using a reducing agent and an SEM image of a perovskite thin film produced with a precursor solution using Ni.

[0025] Figure 5 is a graph showing the total XPS peak of the perovskite thin film prepared from a precursor solution using Ni and Ni 2p. 3 / 2 This is data that enlarges the reference position of the peak.

[0026] Figure 6 shows the PL / TRPL spectra of a perovskite thin film fabricated with a precursor solution using Ni and a perovskite thin film fabricated without using a reducing agent.

[0027] Figure 7 shows the JV graph, EQE, and Integrated J of a pin-structured perovskite solar cell fabricated with a precursor solution using Ni and a solar cell fabricated with a solution without using a reducing agent. SC It shows the data.

[0028] Figure 8 is a diagram showing the JV graph and EQE data of a pin structure all-perovskite tandem solar cell manufactured with a precursor solution using Ni.

[0029] Figure 9 corresponds to the long-term stability data of a pin-structured perovskite solar cell fabricated with a precursor solution using Ni and a solar cell fabricated with a solution without using a reducing agent.

[0030] Figure 10 is an image showing Ni agglomerating by a magnet in a perovskite precursor solution and Sn not agglomerating.

[0031] Hereinafter, specific details for implementing the present disclosure will be described in detail with reference to the attached drawings. However, in the following description, specific descriptions of widely known functions or configurations will be omitted if they may unnecessarily obscure the gist of the present disclosure.

[0032] The terms used in this disclosure will be briefly described, followed by a detailed description of the disclosed embodiments. The terms used in this specification have been selected from widely used, current terms, taking into account the functions of the present disclosure. However, these terms may vary depending on the intentions of engineers working in the relevant fields, precedents, the emergence of new technologies, etc. Furthermore, in certain cases, terms may be arbitrarily selected by the applicant, and in such cases, their meanings will be described in detail in the relevant description of the invention. Therefore, the terms used in this disclosure should not be defined simply as names of terms, but rather based on their meanings and the overall content of the present disclosure.

[0033] In this disclosure, singular expressions include plural expressions unless the context clearly specifies that they are singular. Furthermore, plural expressions include singular expressions unless the context clearly specifies that they are plural.

[0034] In this disclosure, when it is said that a part includes a certain component, this does not mean that other components are excluded, but rather that other components may be included, unless specifically stated otherwise.

[0035] In this specification, the description of “A and / or B” means A, or B, or A and B.

[0036] The term "about" used throughout this specification is used to encompass the tolerance when a tolerance exists.

[0037] Throughout this specification, the term "at least one" in a Markush format expression means including one or more selected from the group consisting of components described in the Markush format expression.

[0038] Throughout this specification, “perovskite” or “PE” or “perovskite compound” means a material having a perovskite crystal structure, which may have various perovskite crystal structures in addition to the crystal structure of ABX3.

[0039] Throughout this specification, the term "optical device" is used to encompass both photoelectric conversion devices and electro-optical conversion devices. For example, optical devices include, but are not limited to, light emitting diodes (LEDs), solar cells, photodetectors, X-ray detectors, and lasers.

[0040] Throughout this specification, the term “halide,” “halogen,” “halide,” or “halo” means a material or composition containing a halogen atom belonging to Group 17 of the Periodic Table in the form of a functional group, which may include, for example, chlorine, bromine, fluorine, or iodine compounds.

[0041] Throughout this specification, “precursor” or “precursor” may mean a precursor or reactant used to prepare perovskite, and is not limited to a specific material.

[0042] Throughout this specification, the term "layer" refers to a layer having a thickness. The layer may be porous or non-porous. Porosity refers to having a void ratio. The layer may be in bulk form or may correspond to a single crystal thin film, but is not limited thereto.

[0043] Throughout this specification, when a member is said to be located "on" another member, unless otherwise specifically stated, this includes not only cases where the member is in contact with the other member, but also cases where another member exists between the two members.

[0044] Throughout this specification, when efficiency is simply described without further explanation, the efficiency refers to power conversion efficiency (PCE).

[0045] The advantages and features of the disclosed embodiments, and methods for achieving them, will become clearer with reference to the embodiments described below, along with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below and may be implemented in various different forms. These embodiments are provided solely to ensure the completeness of the disclosure and to fully inform those skilled in the art of the scope of the invention.

[0046] In the attached drawings, identical or corresponding components are assigned the same reference numerals. Furthermore, in the description of the embodiments below, duplicate descriptions of identical or corresponding components may be omitted. However, even if a description of a component is omitted, it is not intended that such component is not included in any embodiment.

[0047]

[0048] perovskite photonic devices

[0049] An optical device according to one embodiment of the present disclosure may include a first electrode, a first charge transport layer, a perovskite layer, a second charge transport layer, and a second electrode.

[0050] For example, when the photonic device is used in a solar cell having a nip structure, the photonic device may have a structure in which a first electrode, an electron transport layer, a perovskite layer, a hole transport layer, and a second electrode are sequentially stacked. Alternatively, when the photonic device corresponds to a solar cell having a pin structure, the solar cell may have a structure in which a first electrode, a hole transport layer, a perovskite layer, an electron transport layer, and a second electrode are sequentially stacked.

[0051] For example, the photonic device may have a planar structure, a bilayer structure, or a meso-superstructure structure. Depending on the structure of the photonic device, the shapes of the electrodes, charge transport layer, and perovskite layer may be modified.

[0052] For example, when the photonic device has a bi-layer structure, the perovskite layer may have a bi-layer structure formed by filling porous TiO2 with perovskite to form a layer. The bi-layer may mean a structure composed of a first layer of a TiO2: Perovskite mixed layer in which all pores of the porous TiO2 are filled with perovskite, and a second layer of a pure perovskite layer thereon.

[0053] The electrode comprises a first electrode and / or a second electrode, and may be an anode or a cathode. The electrode may be an anode or a cathode. If the first electrode is an anode, the second electrode may be a cathode. For example, the electrode may be a conductive oxide such as indium-tin oxide (ITO), indium-zinc oxide (IZO), flourine-doped tin oxide (FTO), or the like. Alternatively, the electrode may comprise a material selected from the group consisting of silver (Ag), gold (Au), magnesium (Mg), aluminum (Al), platinum (Pt), tungsten (W), copper (Cu), molybdenum (Mo), nickel (Ni), palladium (Pd), chromium (Cr), calcium (Ca), samarium (Sm), and lithium (Li), and combinations thereof. Alternatively, the electrode may correspond to a flexible and transparent material such as plastic, such as PET (polyethylene terephthalate), PEN (polyethylene naphthelate), PP (polyperopylene), PI (polyimide), PC (polycarbornate), PS (polystylene), POM (polyoxyethylene), etc., in which a conductive material is doped.

[0054] The electrode may correspond to a material commonly used as an electrode material for a front electrode or a back electrode in a photonic device. The electrode may be a material selected from one or more of gold, silver, platinum, palladium, copper, aluminum, carbon, cobalt sulfide, copper sulfide, nickel oxide, and a composite thereof, but is not limited thereto. For example, the electrode may be one or more inorganic conductive electrodes selected from fluorine-doped tin oxide (FTO), indium-doped tin oxide (ITO), ZnO, carbon nanotubes (CNT), and graphene, or may correspond to an organic conductive electrode such as PEDOT:PSS, but is not limited thereto.

[0055] As a charge transport layer, an electron transport layer (ETL) or a hole transport layer (HTL) may be formed on the first electrode. If the first charge transport layer is an electron transport layer, the second charge transport layer may correspond to a hole transport layer. Alternatively, if the first charge transport layer is a hole transport layer, the second charge transport layer may correspond to an electron transport layer.

[0056] The electron transport layer may correspond to a semiconductor comprising an "n-type material." The "n-type material" refers to an electron transport material. The electron transport material may be a single electron transport compound or elemental material, or a mixture of two or more electron transport compounds or elemental materials. The electron transport compound or elemental material may be undoped or doped with one or more dopant elements.

[0057] For example, the electron transport layer may be an electron-conducting organic layer or an electron-conducting inorganic layer. The electron-conducting organic layer may be an organic layer used as an n-type semiconductor in a typical organic solar cell. For example, the electron-conducting organic layer may include, but is not limited to, fullerenes (C60, C70, C74, C76, C78, ​​C82, C95), PCBM ([6,6]-phenyl-C61butyric acid methyl ester)), and fullerene-derivatives including C71-PCBM, C84-PCBM, PC70BM ([6,6]-phenyl C70-butyric acid methyl ester), PBI (polybenzimidazole), PTCBI (3,4,9,10-perylenetetracarboxylic bisbenzimidazole), F4-TCNQ (tetra uorotetracyanoquinodimethane), or mixtures thereof.

[0058] The electron-conducting inorganic material may be an electron-conducting metal oxide used for electron transport in a typical quantum dot-based solar cell, dye-sensitized solar cell, or perovskite solar cell. In one embodiment, the electron-conducting metal oxide may be an n-type metal oxide semiconductor. For example, the n-type metal oxide semiconductor may be a material selected from, but not limited to, one or more of Ti oxide, Zn oxide, In oxide, Sn oxide, W oxide, Nb oxide, Mo oxide, Mg oxide, Ba oxide, Zr oxide, Sr oxide, Yr oxide, La oxide, V oxide, Al oxide, Y oxide, Sc oxide, Sm oxide, Ga oxide, In oxide, and SrTi oxide, a mixture thereof, or a composite thereof.

[0059] The electron transport layer may be a dense layer (dense film) or a porous layer (porous film). The dense electron transport layer may be a film of the electron-conducting organic material described above or a dense film of an electron-conducting inorganic material. The electron transport layer of the porous film may be a porous film composed of particles of the electron-conducting inorganic material described above.

[0060] The hole transport layer may correspond to a semiconductor comprising a "p-type material." The "p-type material" refers to a hole transport material. The hole transport material may be a single hole transport compound or elemental material, or a mixture of two or more hole transport compounds or elemental materials. The hole transport compound or elemental material may be undoped or doped with one or more dopant elements. The hole transport material may be an organic hole transport material, an inorganic hole transport material, or a combination thereof.

[0061] The hole transport layer may be manufactured using a solution process. The hole transport layer may be a thin film of an organic hole transport material. The thickness of the hole transport layer thin film may range from 10 nm to 500 nm, but is not limited thereto.

[0062] The hole transport material may be an organic hole transport material, specifically a single molecule or polymer organic hole transport material (hole conducting organic material). The polymer organic hole transport material may include one or more materials selected from thiophene-based, paraphenylenevinylene-based, carbazole-based, and triphenylamine-based compounds.

[0063] Single-molecule to small-molecule organic hole transport materials include pentacene, coumarin 6 (coumarin 6, 3- (2-benzothiazolyl)-7- (diethylamino)coumarin), zinc phthalocyanine (ZnPC), copper phthalocyanine (CuPC), titanium oxide phthalocyanine (TiOPC), Spiro-MeOTAD (2,2',7,7'-tetrakis(N,Np-dimethoxyphenylamino)- 9,9'-spirobifluorene), F16CuPC (copper(II) 1,2,3,4,8,9,10,11,15,16,17,18,22,23,24,25-hexadecafluoro29H,31H-phthalocyanine), and boron subphthalocyanine chloride (SubPc). It may include, but is not limited to, one or more substances selected from N3(cis-di(thiocyanato)-bis(2,2'-bipyridyl-4,4'-dicarboxylic acid)-ruthenium(II)).

[0064] 고분자 유기 정공 수송물질은, P3HT(poly[3-hexylthiophene]), MDMO-PPV(poly[2-methoxy-5-(3',7'- dimethyloctyloxyl)]-1,4-phenylene vinylene), MEH-PPV(poly[2-methoxy -5-(2''-ethylhexyloxy)-p-phenylene vinylene]), P3OT(poly(3-octyl thiophene)), POT( poly(octyl thiophene)), P3DT(poly(3-decyl thiophene)), P3DDT(poly(3-dodecyl thiophene), PPV(poly(p-phenylene vinylene)), TFB(poly(9,9'-dioctylfluorene-co-N-(4-butylphenyl)diphenyl amine), Polyaniline, SpiroMeOTAD ([2,22′,7,77′-tetrkis (N,N-di-p-methoxyphenyl amine)-9,9,9′-spirobi fluorine]), PCPDTBT(Poly[2,1,3-benzothiadiazole- 4,7-diyl[4,4-bis(2-ethylhexyl-4H- cyclopenta [2,1-b:3,4- b']dithiophene-2,6-diyl]], Si-PCPDTBT(poly[(4,4′-bis(2-ethylhexyl)dithieno[3,2-b:2′,3′-d]silole)- 2,6-diyl-alt-(2,1,3-benzothiadiazole)-4,7-diyl]), PBDTTPD(poly((4,8-diethylhexyloxyl) benzo([1,2- b:4,5-b']dithiophene)-2,6-diyl)-alt-((5-octylthieno[3,4-c]pyrrole-4,6-dione)-1,3-diyl)), PFDTBT(poly[2,7-(9-(2-ethylhexyl)-9-hexyl-fluorene)-alt-5,5-(4', 7, -di-2-thienyl-2',1',3'-benzothiadiazole)]), PFO-DBT(poly[2,7-.9,9-(dioctyl-fluorene)-alt-5,5-(4',7'-di-2-.thienyl-2', 1', 3'-benzothiadiazole)]), PSiFDTBT(poly[(2,7-dioctylsilafluorene)-2,7-diyl-alt-(4,7-bis(2-thienyl)-2,1,3-benzothiadiazole)-5,5′-diyl]), PSBTBT(poly[(4,4′-bis(2-ethylhexyl)dithieno[3,2-b:2′,3′-d]silole)- 2,6-diyl-alt-(2,1,3-benzothiadiazole)-4,7-diyl]), PCDTBT(Poly [[9-(1-octylnonyl)-9H-carbazole-2,7- diyl] -2,5-thiophenediyl -2,1,3-benzothiadiazole-4,7-diyl-2,5-thiophenediyl]), PFB (poly(9,9′- dioctylfluorene-co-bis(N,N′-(4,butylphenyl))bis(N,N′-phenyl-1,4-phenylene)diamine), F8BT (poly(9,9′- dioctylfluorene-co-benzothiadiazole), PEDOT (poly(3,4-ethylenedioxythiophene)), PEDOT:PSS (poly(3,4- ethylenedioxythiophene) poly(styrenesulfonate)), PTAA (poly(triarylamine)), Poly(4-butylphenyldiphenyl-amine) and copolymers thereof may include one or more selected from the group consisting of, but is not limited thereto.

[0065] The electron transport layer or hole transport layer may correspond to a buffer layer or may include a buffer layer. The electron transport layer or hole transport layer may have its surface modified by doping. The electron transport layer or hole transport layer may be formed by applying it to one surface of the electrode or coating it in the form of a film through spin coating, dip coating, inkjet printing, gravure printing, spray coating, bar coating, gravure coating, brush painting, thermal evaporation, sputtering, E-Beam, screen printing, blade process, etc.

[0066] The perovskite layer may be formed to be in direct contact with the first electrode. Alternatively, the perovskite layer may be formed to be in direct contact with the electron transport layer or the hole transport layer. The perovskite layer comprises perovskite.

[0067] The perovskite layer can be formed through various processes, including a vapor deposition process or a solution process. The perovskite layer can be formed using a vapor deposition process. The vapor deposition process may correspond to a process in which a material is supplied in a vaporized or plasma state into a vacuum chamber and the material is deposited on a surface of a target object (e.g., a substrate). The perovskite layer can be formed through a coating process during the solution process. The coating process may be selected from the group consisting of, but is not limited to, spin coating, bar coating, nozzle printing, spray coating, slot die coating, gravure printing, inkjet printing, screen printing, electrohydrodynamic jet printing, electrospray, and combinations thereof.

[0068]

[0069] perovskite

[0070] Perovskites may contain monovalent organic cations, divalent metal cations, and halogen anions. The perovskite or perovskite compound according to one embodiment of the present disclosure may satisfy the following chemical formula 1.

[0071]

[0072] [Chemical Formula 1]

[0073] AMX3

[0074]

[0075] In chemical formula 1, A is a monovalent cation, which may be an organic ammonium ion, an amidinium group ion, or a combination of an organic ammonium ion and an amidinium group ion.

[0076] In chemical formula 1, the organic ammonium ion can satisfy the following chemical formula 1-1 or 1-2.

[0077]

[0078] [Chemical Formula 1-1]

[0079] R1-NH3 +

[0080]

[0081] In chemical formula 1-1, R1 is C1-C24 alkyl, C3-C20 cycloalkyl, or C6-C20 aryl.

[0082]

[0083] [Chemical Formula 1-2]

[0084] R2-C3H3N2 + -R3

[0085]

[0086] In chemical formula 1-2, R2 is C1-C24 alkyl, C3-C20 cycloalkyl or C6-C20 aryl, and R3 is hydrogen or C1-C24 alkyl.

[0087] In chemical formula 1, the amidinium ion can satisfy the following chemical formula 1-3.

[0088]

[0089] [Chemical Formula 1-3]

[0090]

[0091]

[0092] In chemical formula 1-3, R4 to R8 are each independently hydrogen, C1-C24 alkyl, C3-C20 cycloalkyl, or C6-C20 aryl.

[0093] In chemical formula 1, A may correspond to an organic ammonium ion, an amidinium group ion, or a combination of an organic ammonium ion and an amidinium group ion. When both an organic ammonium ion and an amidinium group ion are contained, the charge mobility of the perovskite can be significantly improved.

[0094] R1 of Chemical Formula 1-1, R2 to R3 of Chemical Formula 1-2, and / or R4 to R8 of Chemical Formula 1-3 can be appropriately selected depending on the use of the perovskite, i.e., the use of the optical device.

[0095] For example, the size of the unit cell of perovskite is related to the band gap, and it can have a band gap energy of 1.5 to 1.1 eV, which is suitable for use as a solar cell, in a small unit cell size. Accordingly, when considering the band gap energy of 1.5 to 1.1 eV, which is suitable for use as a solar cell, in Chemical Formula 1-1, R1 may be a C1-C24 alkyl, specifically a C1-C7 alkyl, and more specifically, methyl. In addition, in Chemical Formula 1-2, R2 may be a C1-C24 alkyl, and R3 may be hydrogen or a C1-C24 alkyl, specifically, R2 may be a C1-C7 alkyl, and R3 may be hydrogen or a C1-C7 alkyl, and more specifically, R2 may be methyl and R3 may be hydrogen. In addition, in Chemical Formula 1-3, R4 to R8 may be independently hydrogen, amino or C1-C24 alkyl, specifically hydrogen, amino or C1-C7 alkyl, more specifically hydrogen, amino or methyl, and even more specifically R4 may be hydrogen, amino or methyl and R5 to R8 may be hydrogen. As a specific and non-limiting example, the amidinium ion may be formamidinium (NH2CH=NH2 + ) ion, acetamidinium (NH2C(CH3)=NH2 + ) ion or guamidinium (NH2C(NH2)=NH2 + ) ions, etc.

[0096] As described above, specific examples of organic cations (A) are examples that take into account the use of the perovskite film, i.e., use as a light-absorbing layer for sunlight, and R1 of Chemical Formula 1-1, R2 to R3 of Chemical Formula 1-2, and / or R4 to R8 of Chemical Formula 1-3 may be appropriately selected in consideration of the design of the wavelength band of light to be absorbed, the design of the emission wavelength band when used as a light-emitting layer of a light-emitting device, and the energy band gap and threshold voltage when used as a semiconductor device of a transistor.

[0097] In Chemical Formula 1, M can be a divalent metal ion. As a specific example, M is Cu 2+ , Ni 2+ , Co 2+ , Fe 2+ , Mn 2+ , Cr 2+ , Pd 2+ , Cd 2+ , Ge 2+ , Sn 2+ , Pb 2+ and Yb 2+ It may be one or more metal ions selected from .

[0098] In chemical formula 1, X is a halogen anion. Specifically, the halogen ion is I - , Br - , F - , Cl - and combinations thereof. Including, but not limited to, a halogen ion selected from the group consisting of: For example, X may correspond to an oxygen ion.

[0099] More specifically, the halogen anion may contain iodine ions and bromine ions. When the halogen anion contains both iodine ions and bromine ions, the crystallinity and moisture resistance of the perovskite can be improved.

[0100] As a specific example, in chemical formula 1, X is X a (1-y) Xb y It could be, X a and X b are different halogen ions (iodine ion (I - ), chlorine ion (Cl - ) and bromine ion (Br - ) are different halogen ions selected from each other, and y can be a real number such that 0<y<1.

[0101]

[0102] perovskite precursor

[0103] “Precursor” may mean a precursor or reactant used to manufacture perovskite, and is not limited to a specific material.

[0104] “Halide precursor” includes organic halide precursors and metal halide precursors.

[0105] The perovskite precursor may correspond to an organic cation, a metal cation, or a halogen anion (X). The organic cation, metal ion, and halogen anion contained in the precursor may be the same as the monovalent organic cation (A), divalent metal ion (M), and halogen anion (X) described above in perovskite, and therefore, a detailed description thereof is omitted.

[0106] The organic halide may correspond to the chemical formula AX, where A is an organic cation and X may include a halide anion, but is not limited thereto. For example, the organic halide may include, but is not limited to, Formamidinium Iodide (FAI).

[0107] An organic cation is a cation that contains carbon. Organic cations may additionally contain other elements, for example, hydrogen, nitrogen, or oxygen.

[0108] For example, the organic cation included in the organic halide may include at least one of methylammonium (MA), formamidinium (FA), or a combination thereof. For example, the organic halide may correspond to at least one of methylammonium chloride, methylammonium bromide, methylammonium iodide, formamidinium chloride, formamidinium bromide, or formamidinium iodide.

[0109] For example, organic cations have the chemical formula (R1R2R3R4N) + may have. In this case, R1~R4 may correspond to hydrogen, unsubstituted or substituted C1-C20 alkyl, or unsubstituted or substituted aryl.

[0110] For example, an organic cation has the chemical formula (R5NH3) + , wherein R5 may correspond to hydrogen, or substituted or unsubstituted C1-C20 alkyl.

[0111] For example, an organic cation has the chemical formula (R6R7N=CH-NR8R9) + , and in this case, R6~R9 can correspond to hydrogen, methyl, or ethyl.

[0112] Throughout the present specification, the metal halide may correspond to the chemical formula BX2, wherein B comprises a metal cation selected from the group consisting of Pb, Sn, Cu, Ni, Co, Fe, Mn, Cr, Pd, Cd, Yb, Ge, Ca, Sr, Eu and combinations thereof, and X may comprise a halide anion, but is not limited thereto.

[0113] In terms of crystal structure, the precursor can be an amorphous, crystalline, or a mixture of amorphous and crystalline materials.

[0114] The perovskite precursor comprises a dispersion containing the perovskite precursor or an ink containing the perovskite precursor described above. The dispersion or ink may further contain known additives, along with the perovskite precursor and dispersion medium described above, so as to have properties suitable for application or printing methods.

[0115] A perovskite precursor can be manufactured by a step of adding a solution containing an organic cation, a metal cation, and a halogen ion according to the stoichiometric ratio of perovskite dropwise to a nonsolvent, and a step of recovering and drying a solid phase obtained by the dropwise addition. Here, the obtained solid phase may correspond to a crystalline solid powder. The solid phase can be recovered using a method commonly used in solid-liquid separation. Examples include, but are not limited to, filtering and centrifugation. Drying is sufficient as long as the perovskite precursor is not thermally damaged. For example, drying can be performed at room temperature to 50 degrees Celsius.

[0116] The perovskite precursor solution may correspond to a substance in which a solvent is added to the above-described components. For example, a solvent that dissolves a typical perovskite may be used as the solvent. The solvent that dissolves the perovskite precursor may be any solvent that dissolves the perovskite and is easily volatile and removable. Specific examples include gamma-butyrolactone (GBL), 1-methyl-2-pyrolidinone, etc., but the present invention is not limited thereto. The first solution may be prepared by dissolving an organic cation, a metal cation, and a halogen ion in a solvent.

[0117] According to one embodiment of the present disclosure, the solvent may mean a polar organic solvent, and may mean an organic solvent in which the solubility of the perovskite compound is 0.5 M or more, specifically 0.8 M or more, at 20 degrees Celsius and 1 atm. Examples of solvents that dissolve the perovskite compound include N,N-dimethylacetamid, 1,4-dioxane, diethylamine, ethyl acetate, tetrahydrofuran, pyridine, methanol, ethanol, dichlorobenzene, glycerin, and dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), gamma-butyrolactone (GBL), 1-methyl-2-pyrolidinone, or mixtures thereof.

[0118] Since the perovskite precursor may have similar or identical properties (such as solubility) to perovskite in organic solvents, the non-solvent may refer to an organic solvent that does not dissolve perovskite. In this case, "not dissolving perovskite" may refer to an organic solvent in which the solubility of perovskite is less than 0.1 M, specifically less than 0.01 M, and more specifically less than 0.001 M, at 20 degrees Celsius and 1 atm.

[0119] As an example of a non-solvent, a non-polar organic solvent may be mentioned, and the non-polar organic solvent may be an organic solvent selected from one or more of pentane, hexene, cyclohexene, 1,4-dioxene, benzene, toluene, triethyl amine, chlorobenzene, ethylamine, ethyl ether, chloroform, ethyl acetate, acetic acid, 1,2-dichlorobenzene, tert-butyl alcohol, 2-butanol, isopropanol, and methyl ethyl ketone, but the present invention is not limited thereto.

[0120] For example, a solution in which a perovskite precursor is dissolved or a dispersion or ink in which a perovskite precursor is dispersed can be applied to a substrate and then dried to form a perovskite thin film layer.

[0121] As another example, when the perovskite precursor is a solvent compound, a solution is prepared by dissolving organic cations, metal cations, and halogen ions in a solvent according to the stoichiometric ratio of perovskite, and then the prepared solution is applied onto a substrate and a non-solvent is re-applied to the applied film, thereby producing a perovskite thin film layer containing the perovskite precursor.

[0122] Application of a solution, dispersion or ink can be performed by one or more methods selected from screen printing, spin coating, bar coating, gravure coating, blade coating and roll coating, but considering the excellent commercial feasibility of processing a large area in a short period of time, spin coating is preferred.

[0123] For example, a perovskite thin film can be formed by applying energy to a solvent containing a perovskite precursor. The energy applied to the perovskite precursor may include thermal energy, light energy, vibrational energy, etc. For example, by heating the perovskite precursor to 100 degrees (Celsius) or higher, crystalline perovskite can be obtained, and further, when heated to 130 degrees (Celsius) or higher, crystalline perovskite can be obtained in a very short period of time. At this time, the upper limit of the heat treatment for converting the perovskite precursor into perovskite is sufficient as long as the substrate on which the perovskite is to be formed is not thermally damaged. For example, the heat treatment can be performed at 100 to 200 degrees (Celsius). The heat treatment time is sufficient as long as the perovskite precursor can be sufficiently converted into perovskite, taking the heat treatment temperature into consideration. As a non-limiting example, the heat treatment time may be from 1 minute to 30 minutes, but it is to be understood that the present invention is not limited by the heat treatment time.

[0124]

[0125] Example

[0126] In the present disclosure, Ni is added to a halide perovskite precursor solution containing Sn, and Sn present in the solution 4+ Sn 2+ We propose a method of reducing the reducing agent to nickel and a method of reusing the reducing agent without a separate filtration process by utilizing the magnetic properties of nickel.

[0127] Since Sn is unstable as a divalent ion, it is used in halide perovskites. 4+ There is a problem that it is easily oxidized. In the present disclosure, Ni with excellent reducibility is used to produce Sn generated in the precursor solution stage. 4+ We propose a method to reduce the defect density of perovskite thin films and improve the efficiency and stability of solar cell devices by reducing .

[0128] Figure 1 shows the oxidized Sn by adding Ni to the Sn-based perovskite precursor solution used in the present invention. 4+ A schematic diagram of the process of reducing Sn and a method of reusing Ni without filtering it out. In addition, Fig. 2 is a schematic diagram showing a method of filtering Sn and Ni metals.

[0129] Referring to Figures 1 and 2, first, a container containing a perovskite precursor solution containing Sn ions is prepared (a). The perovskite precursor solution contains Sn 2+ As well as oxidized Sn 4+ There is also.

[0130] Afterwards, Ni is added to the perovskite precursor solution (b). Due to the high reducibility of Ni, Sn 4+ This Sn 2+ (c). A magnet is placed outside the container containing the perovskite precursor solution (d). In order to apply a magnetic force to the perovskite precursor solution, the magnet can be placed in various ways. For example, the magnet can be placed at the bottom of the container. Alternatively, the magnet can also be placed inside the container. The position or number of magnets can be changed as long as the position can apply a magnetic force to Ni. Ni included in the perovskite precursor solution is aggregated within the container adjacent to the placed magnet. For example, Ni can be aggregated at the bottom inside the container. The perovskite precursor solution excluding Ni is discharged from the container, and the Ni remaining at the bottom of the container is recycled (e). In this process, Ni can be removed by the magnetic force applied to the perovskite precursor solution.

[0131] Figure 3 shows XRD patterns of perovskite thin films fabricated using a precursor solution containing Ni and those fabricated without using a reducing agent. The XRD patterns confirm that the use of Ni does not affect the crystal structure or crystallinity.

[0132] Figure 4 shows an SEM image of a perovskite thin film (left) without using a reducing agent, and an SEM image of a perovskite thin film (right) fabricated with a precursor solution containing Ni. This demonstrates that the use of Ni does not alter the surface morphology or grain size.

[0133] Figure 5 is a graph showing the total XPS peak of the perovskite thin film prepared from a precursor solution using Ni and Ni 2p. 3 / 2 This graph shows data that magnifies the reference position of the peak. This graph confirms that no nickel remains in the thin film.

[0134] Figure 6 shows the PL / TRPL spectra of perovskite films fabricated using a precursor solution containing Ni and those fabricated without using a reducing agent. The graph confirms that the use of Ni has a positive effect on the amount of non-radiative recombination and the carrier lifetime.

[0135] Figure 7 shows the JV graph, EQE, and Integrated J of a pin-structured perovskite solar cell fabricated with a precursor solution using Ni and a solar cell fabricated with a solution without using a reducing agent. SC This corresponds to the data. The data confirms that the use of Ni improves the performance of solar cell devices.

[0136] Figure 8 is a diagram illustrating the JV graph and EQE data of a pin-structured all-perovskite tandem solar cell fabricated with a precursor solution using Ni. The data illustrated in Figure 9 confirm that the use of Ni can be applied not only to single-junction solar cells but also to tandem solar cells.

[0137] Figure 9 shows long-term stability data for a pin-structured perovskite solar cell fabricated with a precursor solution containing Ni and a solar cell fabricated with a solution containing no reducing agent. These data confirm that the use of Ni enhances the stability of the solar cell device.

[0138] Figure 10 is an image showing Ni agglomerating by a magnet in a perovskite precursor solution and Sn not agglomerating.

[0139]

[0140] Manufacturing example

[0141] All processes of the present invention were carried out inside a glove box in an Ar atmosphere, and the concentrations of O2 and H2O detected in the glove box were both 0.1 ppm or less.

[0142]

[0143] Example 1: Preparation of perovskite solution

[0144] FAI, MAI, CsI, PbI2, and SnI2 were added to vials at 0.99 M, 0.72 M, 0.09 M, 0.72 M, and 1.08 M, respectively. Then, DMF and DMSO were added in a volume ratio of 4:1 to obtain a concentration of 1.8 M FA. 0.55 MA 0.4 Cs 0.05 Pb 0.4 Sn 0.6 An I3 perovskite precursor solution was prepared.

[0145]

[0146] Example 2: Addition of reducing agent Ni

[0147] The prepared perovskite precursor solution was filtered through a 0.2 μm PTFE membrane filter and transferred to a vial containing 0.054 M Ni. The solution was then shaken for 5–10 minutes to ensure sufficient reaction.

[0148]

[0149] Example 3: Collection and reuse of Ni

[0150] A neodymium magnet was placed against the bottom of the vial containing Ni, and the Ni was allowed to completely collect. The perovskite thin film fabrication process was then conducted with the Ni collected, with care taken to ensure that the Ni was not momentarily detached by the pressure of the micropipette.

[0151]

[0152] Comparative Example: Preparation and Use of Perovskite Precursor Solution without Reducing Agent>

[0153] A perovskite precursor solution was prepared in the same manner as in Example 1, and the filtered perovskite precursor solution was transferred to a Ni-free vial in the same manner as in Example 2, and used as is in the process of preparing a perovskite thin film.

[0154]

[0155] The above preferred embodiments of the present invention are disclosed for the purpose of illustration, and those skilled in the art with ordinary knowledge of the present invention will be able to make various modifications, changes, and additions within the spirit and scope of the present invention, and such modifications, changes, and additions should be considered to fall within the scope of the patent claims.

[0156] Anyone having ordinary skill in the art to which the present invention pertains can make various substitutions, modifications, and changes within the scope that does not depart from the technical spirit of the present invention, and therefore the present invention is not limited to the above-described embodiments and the attached drawings.

Claims

1. Halide precursor; Sn ion; Reducing agent Ni; and menstruum Including, The above Sn ion is Sn 2+ and Sn 4+ A perovskite precursor solution comprising:

2. In paragraph 1, Reducing agent Ni is Sn 4+ Sn 2+ A perovskite precursor solution that reduces to .

3. In paragraph 2, A perovskite precursor solution, wherein the solvent comprises at least one of DMF and DMSO.

4. In paragraph 1, A perovskite precursor solution wherein the halide precursor comprises an organic halide.

5. In paragraph 4, A perovskite precursor solution wherein the organic halide comprises at least one of methylammonium (MA) and formamidinium (FA), or a combination thereof.

6. In paragraph 1, A perovskite precursor solution wherein the above reducing agent Ni is removed from the perovskite precursor solution by magnetic force.

7. A step of preparing a container containing a perovskite precursor solution containing Sn ions; A step of adding a reducing agent, Ni, to the above perovskite precursor solution; A step of applying a magnetic force to the perovskite precursor solution; and A step of discharging the perovskite precursor solution excluding the above reducing agent Ni from the container. A method for preparing a perovskite precursor solution, comprising:

8. In paragraph 7, The above Sn ion is Sn 2+ and Sn 4+ A method for preparing a perovskite precursor solution, comprising:

9. In paragraph 8, Reducing agent Ni is Sn 4+ Sn 2+ A method for preparing a perovskite precursor solution by reducing it to .

10. A perovskite photonic device manufactured using a perovskite precursor solution according to paragraph 1.

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