Tandem type silicon / perovskite heterojunction solar cell and manufacturing method therefor

Abstract

The present invention relates to a heterojunction solar cell and a manufacturing method therefor, the heterojunction solar cell formed of a sequentially stacked solar cell, transparent conductive layer, hole transport layer, perovskite light-absorbing layer, electron transport layer, transparent electrode and metal electrode, wherein the perovskite light-absorbing layer includes a perovskite material, represented by chemical formula 1, and benzylhydrazine oxalate salt, charge collection capability can be increased by reducing charge recombination in the perovskite light-absorbing layer, and degradation of the solar cell can be reduced such that improved performance can be exhibited in terms of stability. [Chemical formula 1] FACsPbX3 In chemical formula 1, X is a monovalent anion.

Description

Tandem silicon / perovskite heterojunction solar cell and method for manufacturing the same

[0001] The present invention relates to a tandem silicon / perovskite heterojunction solar cell introducing benzylhydrazine oxalate salt as an additive to a perovskite light-absorbing layer, and a method for manufacturing the same.

[0002]

[0003] To address the depletion of fossil fuels and the global environmental problems caused by their use, research is actively being conducted on renewable and clean alternative energy sources such as solar energy, wind power, and hydropower.

[0004] Among these, interest in solar cells, which directly convert sunlight into electrical energy, is growing significantly. Here, a solar cell refers to a cell that generates current and voltage by utilizing the photovoltaic effect, which generates electrons and holes by absorbing light energy from sunlight.

[0005] Currently, it is possible to manufacture np diode-type silicon (Si) single crystal-based solar cells with a light energy conversion efficiency of over 20%, and these are actually being used for solar power generation. There are also solar cells using compound semiconductors such as gallium arsenide (GaAs) with even better conversion efficiencies. However, these inorganic semiconductor-based solar cells require highly purified materials to achieve high efficiency, so a lot of energy is consumed in refining the raw materials. In addition, expensive processing equipment is required in the process of forming single crystals or thin films using the raw materials, which limits the cost of lowering the manufacturing cost of solar cells, and this has been an obstacle to large-scale utilization.

[0006] Accordingly, in order to manufacture solar cells at low cost, it is necessary to drastically reduce the cost of materials or manufacturing processes used as core components of solar cells, and research is being conducted on perovskite solar cells that can be manufactured using low-cost materials and processes as an alternative to inorganic semiconductor-based solar cells.

[0007] Recently, perovskite solar cells using (NH3CH3)PbX3 (X=I, Br, Cl), a halogen compound with a perovskite structure, as a photoactive agent have been developed, and research is being conducted toward commercialization. The general structural formula of the perovskite structure is the ABX3 structure, where anions are located in the X position, large cations are located in the A position, and small cations are located in the B position.

[0008] Perovskite solar cells, which are organometallic halide compounds with the molecular formula (CH3NH3)PbX3, were first used as photoactive materials in solar cells in 2009. Since then, since the development of solid-state perovskite solar cells with the current structure in 2012, their efficiency has been rapidly improved. Conventional perovskite solar cells use metal oxides as electron transport layers and hole transport layers (HTL), but organic or polymeric materials such as spiro-OMETAD can also be used. That is, a porous film or thin film of metal oxide is fabricated as an electron transport layer / hole transport layer on a transparent electrode such as FTO / ITO, and the perovskite material is coated. After that, a porous film or thin film of metal oxide is fabricated as a hole transport layer / electron transport layer, and then an electrode layer such as gold (Au) or silver (Ag) is deposited.

[0009] Perovskite solar cells, which are organometallic halide compounds with the molecular formula (CH3NH3)PbX3, use halide ions such as I, Br, and Cl in the molecular formula, and the excess halide that does not participate in the formation of the perovskite crystal phase exists in the form of ionic defects and is not fixed to the perovskite crystal, but can escape from the crystal in the form of halide combined with hydrogen or light cations, thus having high diffusivity. Therefore, after the fabrication of Si / perovskite tandem solar cells, halide ions easily diffuse into the surrounding layers without restriction due to heating, light irradiation, or electrical external factors that are essential in subsequent module processes.

[0010] Meanwhile, the upper perovskite film applied to the tandem solar cell is configured with a band gap of 1.60 to 1.70 eV for current matching with the lower silicon solar cell in a two-terminal structure, and the band gap of the perovskite can be controlled depending on the ratio of ABX3 constituting the perovskite. MA is a material corresponding to the A site among the composition materials of the perovskite film for constructing the tandem solar cell. + (methyl ammonium cation), FA + (Formamidinium cation), Cs + (cesium cation) and is composed of a combination of these.

[0011] Recently, MA + Due to the thermal stability issues of MA + A perovskite layer that does not contain Pb is being developed. The material corresponding to the B site is Pb 2+ (lead cation), the substance corresponding to the X site is Cl - (chloride anion), Br - (Bromide anion), I -The form of the perovskite composition consisting of (iodide anion) and combinations thereof is generally used as the upper layer of tandem solar cells.

[0012] Methods for producing perovskite thin films are broadly categorized into coating (=solution) process and deposition process. The deposition process has the disadvantage of requiring vacuum equipment, so the coating (=solution) process, which is a simpler method of production, is the main method.

[0013] To form a conventional perovskite thin film, perovskite materials are placed in a solvent to form a precursor solution. The solvents used at this time are mainly DMF and 2-ME, and NMP, DMPU, HMPA, and THTO are used as additional solvents. When storing the solutions, I - Ions are I2 / I3 - , which is easily reduced to perovskite, which degrades the performance of silicon / perovskite tandem solar cells in the long term.

[0014] Meanwhile, in the coating (=solution) process, a heat treatment in the solution state is essential for producing a perovskite layer, crystallizing it into a thin film. However, this process fails to achieve perfect crystallization without loss of composition, and defects inevitably occur during the heat treatment. Furthermore, rapid crystallization often fails to produce large grain sizes, resulting in the formation of numerous grain boundaries. These can act as recombination centers for charge transfer, hindering good performance.

[0015] In particular, when it diffuses into a metal electrode such as gold (Au) or silver (Ag) in a Si / perovskite tandem solar cell, it not only corrodes the interface between the transparent electrode and the metal electrode, increasing the interfacial contact resistance, but also causes metal ion leakage into the solar cell due to the corrosion of the metal electrode, which reduces the performance of the solar cell.

[0016]

[0017] The present invention has been devised to overcome the above-described problems, and provides a tandem silicon / perovskite heterojunction solar cell and a method for manufacturing the same, which can increase charge collection capacity by reducing charge recombination in a perovskite light-absorbing layer by introducing benzylhydrazine oxalate salt as an additive to the perovskite light-absorbing layer, and can also reduce deterioration of the solar cell, thereby showing improved performance in terms of stability.

[0018]

[0019] In order to solve the above-described problem, the tandem silicon / perovskite heterojunction solar cell of the present invention is a heterojunction solar cell in which a solar cell, a transparent conductive layer, a hole transport layer, a perovskite light-absorbing layer, an electron transport layer, a transparent electrode, and a metal electrode are sequentially laminated.

[0020] As a preferred embodiment of the present invention, the perovskite light-absorbing layer may include a perovskite material represented by the following chemical formula 1 and benzylhydrazine oxalate salt.

[0021] [Chemical Formula 1]

[0022] FACsPbX3

[0023] In the above chemical formula 1, X is a monovalent anion.

[0024] As a preferred embodiment of the present invention, the perovskite light-absorbing layer may include the perovskite material represented by the chemical formula 1 and benzylhydrazine oxalate in a weight ratio of 1:0.0001 to 0.002.

[0025] As a preferred embodiment of the present invention, the perovskite light-absorbing layer may have an average thickness of 450 to 700 nm.

[0026] As a preferred embodiment of the present invention, a first interface layer may be further included between the hole transport layer and the perovskite light absorbing layer.

[0027] As a preferred embodiment of the present invention, the first interface layer may include a P-type organic molecule SAM interface coating agent.

[0028] As a preferred embodiment of the present invention, the first interface layer may have a thickness of 0.5 nm to 10 nm.

[0029] As a preferred embodiment of the present invention, a second interfacial layer may be further included between the perovskite light-absorbing layer and the electron transport layer.

[0030] As a preferred embodiment of the present invention, the second interface layer may include at least one selected from lithium fluoride (LiF), magnesium fluoride (MgF2), cesium fluoride (CsF), sodium fluoride (NaF), potassium fluoride (KF), aluminum fluoride (AlF3), and calcium fluoride (CaF2).

[0031] As a preferred embodiment of the present invention, the second interface layer may have a thickness of 0.5 nm to 10 nm.

[0032] As a preferred embodiment of the present invention, an intermediate layer may be further included between the second interface layer and the electron transport layer.

[0033] As a preferred embodiment of the present invention, the intermediate layer may include a fullerene-based organic material.

[0034] Meanwhile, the method for manufacturing a tandem silicon / perovskite heterojunction solar cell of the present invention may include a first step of sequentially stacking a solar cell, a transparent conductive layer, a hole transport layer, and a first interface layer, a second step of forming a perovskite light-absorbing layer on top of the first interface layer through a coating method, and a third step of sequentially forming a second interface layer, an intermediate layer, an electron transport layer, a transparent electrode, and a metal electrode on top of the perovskite light-absorbing layer.

[0035] As a preferred embodiment of the present invention, the perovskite light-absorbing layer may include a perovskite material represented by the following chemical formula 1 and benzylhydrazine oxalate salt.

[0036] [Chemical Formula 1]

[0037] FACsPbX3

[0038] In the above chemical formula 1, X is a monovalent anion.

[0039] In a preferred embodiment of the present invention, the coating method may be a gravure coating method, a bar coating method, a printing method, a spray coating method, a spin coating method, a blade coating method, a dip method, or a die coat method.

[0040] As a preferred embodiment of the present invention, the perovskite light-absorbing layer may be a mixture of the perovskite material represented by the chemical formula 1 and benzylhydrazine oxalate in a weight ratio of 1:0.0001 to 0.002.

[0041] As a preferred embodiment of the present invention, the first interface layer can be formed by including the step (1) of heating a hole transport layer, the step (2) of coating a P-type organic molecule SAM interface coating agent on top of the heated hole transport layer, and the step (3) of drying the coated P-type organic molecule SAM interface coating agent to form the first interface layer.

[0042]

[0043] The tandem silicon / perovskite heterojunction solar cell of the present invention and its manufacturing method introduce benzylhydrazine oxalate as an additive when forming a perovskite light-absorbing layer, thereby I2 / I3 - To I - can reduce trap creation by reducing it.

[0044] In addition, the tandem silicon / perovskite heterojunction solar cell of the present invention and its manufacturing method can delay the growth of nuclei during crystal growth of a perovskite light-absorbing layer, thereby allowing better growth into a single grain.

[0045] In addition, the tandem silicon / perovskite heterojunction solar cell of the present invention and the method for manufacturing the same have halide defects (C2O4). 2- By replacing it with , the defects created can be more effectively alleviated.

[0046]

[0047] Hereinafter, the present invention will be described in more detail.

[0048] To form a conventional perovskite thin film, perovskite materials are placed in a solvent to form a precursor solution. The solvents used at this time are mainly DMF and 2-ME, and NMP, DMPU, HMPA, and THTO are used as additional solvents. When storing the solutions, I - Ions are I2 / I3 -, which is easily reduced to perovskite, which degrades the performance of silicon / perovskite tandem solar cells in the long term.

[0049] Meanwhile, in the coating (=solution) process, a heat treatment in the solution state is essential for producing a perovskite layer, crystallizing it into a thin film. However, this process fails to achieve perfect crystallization without loss of composition, and defects inevitably occur during the heat treatment. Furthermore, rapid crystallization often fails to produce large grain sizes, resulting in the formation of numerous grain boundaries. These can act as recombination centers for charge transfer, hindering good performance.

[0050] In particular, when it diffuses into a metal electrode such as gold (Au) or silver (Ag) in a Si / perovskite tandem solar cell, it not only corrodes the interface between the transparent electrode and the metal electrode, increasing the interfacial contact resistance, but also causes metal ion leakage into the solar cell due to the corrosion of the metal electrode, which reduces the performance of the solar cell.

[0051] Accordingly, the present invention relates to a tandem silicon / perovskite heterojunction solar cell that can increase charge collection capacity by reducing charge recombination in a perovskite light-absorbing layer by introducing benzylhydrazine oxalate salt as an additive to the perovskite light-absorbing layer, and can also reduce deterioration of the solar cell, thereby showing improved performance in terms of stability.

[0052]

[0053] The tandem silicon / perovskite heterojunction solar cell of the present invention may be a heterojunction solar cell having a structure in which a solar cell, a transparent conductive layer, a hole transport layer, a perovskite light-absorbing layer, an electron transport layer, a transparent electrode, and a metal electrode are sequentially laminated.

[0054] In addition, the tandem silicon / perovskite heterojunction solar cell of the present invention may further include a first interfacial layer between the hole transport layer and the perovskite light-absorbing layer. In this case, the tandem silicon / perovskite heterojunction solar cell of the present invention may be a heterojunction solar cell having a structure in which a solar cell, a transparent conductive layer, a hole transport layer, a first interfacial layer, a perovskite light-absorbing layer, an electron transport layer, a transparent electrode, and a metal electrode are sequentially laminated.

[0055] In addition, the tandem silicon / perovskite heterojunction solar cell of the present invention may further include a second interfacial layer between the perovskite light-absorbing layer and the electron transport layer. In this case, the tandem silicon / perovskite heterojunction solar cell of the present invention may be a heterojunction solar cell having a structure in which a solar cell, a transparent conductive layer, a hole transport layer, a perovskite light-absorbing layer, a second interfacial layer, an electron transport layer, a transparent electrode, and a metal electrode are sequentially laminated.

[0056] Meanwhile, the tandem silicon / perovskite heterojunction solar cell of the present invention may be a heterojunction solar cell having a structure in which a solar cell, a transparent conductive layer, a hole transport layer, a first interface layer, a perovskite light-absorbing layer, a second interface layer, an electron transport layer, a transparent electrode, and a metal electrode are sequentially laminated.

[0057] In addition, the tandem silicon / perovskite heterojunction solar cell of the present invention may further include an intermediate layer between the second interface layer and the electron transport layer. In this case, the tandem silicon / perovskite heterojunction solar cell of the present invention may be a heterojunction solar cell having a structure in which a solar cell, a transparent conductive layer, a hole transport layer, a first interface layer, a perovskite light-absorbing layer, a second interface layer, an intermediate layer, an electron transport layer, a transparent electrode, and a metal electrode are sequentially laminated.

[0058]

[0059] The solar cell may be a polycrystalline silicon solar cell, a crystalline silicon solar cell, a perovskite solar cell, a gallium arsenide (GaAs) solar cell, a cadmium telluride (CdTe) solar cell, a CIGS (CuInGaSe) solar cell, a CZTS (Cu2ZnSnS4) solar cell, an organic solar cell, a fuel-sensitized solar cell, or a group III-V compound solar cell.

[0060] In addition, there is no separate limitation on the thickness of the solar cell, but it may preferably have a thickness of 140 to 250 μm, more preferably 160 to 200 μm.

[0061] The transparent conductive layer is a layer that induces recombination of electrons and holes generated in a solar cell and a perovskite light-absorbing layer to be described later, and may be a transparent thin film on which ITO (Indium Tin Oxide), FTO (Fluorine doped Tin Oxide), ATO (Sb2O3 doped Tin Oxide), GTO (Gallium doped Tin Oxide), ZTO (tin doped zinc oxide), ZTO:Ga (gallium doped ZTO), IGZO (Indium gallium zinc oxide), IZO (Indium doped zinc oxide), or AZO (Aluminum doped zinc oxide) is deposited.

[0062] In addition, as an example of forming a transparent conductive layer, when using a silicon solar cell doped with n- or p-type impurities as a solar cell, the silicon solar cell doped with n- or p-type impurities is treated with hydrofluoric acid to remove the SiOx oxide film, and then the remaining hydrofluoric acid is removed using ultrapure water. Then, a transparent conductive layer can be formed on the top of the silicon solar cell from which the oxide film has been removed through a sputtering process.

[0063] In addition, the thickness of the transparent conductive layer is not particularly limited, but may preferably have a thickness of 5 nm to 50 nm, more preferably 15 nm to 25 nm.

[0064] The hole transport layer (HTL) is a layer that transports holes formed in the perovskite light-absorbing layer described below while simultaneously blocking the movement of electrons, and may include an inorganic and / or organic hole transport material.

[0065] At this time, the inorganic hole transport material may include at least one selected from nickel oxide (NiOx), CuSCN, CuCrO2, CuI, MoO, and V2O5.

[0066] In addition, organic hole transport materials include carbazole derivatives, polyarylalkane derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, styrylanthracene derivatives, fluorene derivatives, hydrazone derivatives, stilbene derivatives, silazane derivatives, aromatic tertiary amine compounds, styrylamine compounds, aromatic dimethylidine compounds, porphyrin compounds, phthalocyanine compounds, polythiophene derivatives, polypyrrole derivatives, polyparaphenylenevinylene derivatives, pentacene, coumarin 6 (coumarin 6, 3-(2-benzothiazolyl)-7-(diethylamino)coumarin), ZnPC (zinc phthalocyanine), CuPC (copper phthalocyanine), TiOPC (titanium oxide phthalocyanine), 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-hexadecafluoro-29H,31H-phthalocyanine), SubPc (boron subphthalocyanine chloride) and N3(cis-di(thiocyanato)-bis(2,2'-bipyridyl-4,4'-dicarboxylic acid)-ruthenium(II), 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), 폴리아닐린(Polyaniline), Spiro-MeOTAD([2,22′,7,77′-tetrkis (N,N-di-pmethoxyphenyl 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), 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]), 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,It may include at least one selected from among 9′-dioctylfluorene-co-bis(N,N′-(4,butylphenyl))bis(N,N′-phenyl-1,4-phenylene)diamine), F8BT(poly(9,9′-dioctylfluorene-cobenzothiadiazole), PEDOT (poly(3,4-ethylenedioxythiophene)), PEDOT:PSS poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate), PTAA (poly(triarylamine)), 2-PACz, MeO-2PACz, Br-2PACz, and Me-4PACz.

[0067] In addition, methods for forming a hole transport layer include a coating method and a vacuum deposition method, and methods for applying the hole transport layer include a gravure coating method, a bar coating method, a printing method, a spray method, a spin coating method, a blade coating method, a dip method, and a die coat method.

[0068] In addition, the thickness of the hole transport layer is not particularly limited, but may preferably have a thickness of 5 nm to 40 nm, more preferably 10 nm to 30 nm.

[0069]

[0070] The first interface layer plays a role in effectively transporting holes by controlling the work function of the hole transport layer, and may include a P-type organic molecule SAM interface coating agent. The P-type organic molecule SAM interface coating agent may include a PACz-based compound and a solvent.

[0071] The PACz-based compound may include at least one selected from 2-PACz (2-(9H-Carbazol-9-yl)ethyl]phosphonic acid), MeO-2PACz, Br-2PACz, Me-4PACz, MeO-4PACz, 6-PACz, and Me-6PACz. In addition, the P-type organic molecule SAM interfacial coating agent may include the PACz-based compound at a concentration of 0.30 mg / ml to 10.00 mg / ml.

[0072] The solvent may include at least one selected from methanol, ethanol, 1-propanol, and 1-butanol.

[0073] Additionally, the first interface layer may have a thickness of 0.5 nm to 10 nm, preferably 2 nm to 8 nm.

[0074] Additionally, the first interface layer may have a surface roughness RMS (Root-mean square) of 4.50 to 80.00 nm, and preferably 5.00 to 50.00 nm.

[0075] In addition, methods for forming the first interface layer include a coating method and a vacuum deposition method, and methods for applying the first interface layer include a gravure coating method, a bar coating method, a printing method, a spray method, a spin coating method, a blade coating method, a dip method, and a die coat method.

[0076]

[0077] The perovskite light-absorbing layer may include a perovskite material represented by the following chemical formula 1 and benzylhydrazine oxalate salt.

[0078] [Chemical Formula 1]

[0079] FACsPbX3

[0080] In the above chemical formula 1, X is a monovalent anion. Specifically, X may include one or more monovalent anions selected from iodide, bromide, chloride, fluoride, thiocyanate, cyanate, selenocyanate, formate, and acetate.

[0081] A desirable example is X is I x Br 3-x (0≤x≤3) may be. And, as an example of a preferred embodiment of the chemical formula 1, FACsPbI x Br 3-x (0≤x≤3) may be.

[0082] Specifically, the perovskite light-absorbing layer may include the perovskite material represented by the above chemical formula 1 and benzylhydrazine oxalate in a weight ratio of 1:0.0001 to 0.002, preferably 1:0.0003 to 0.0014, and more preferably 1:0.0004 to 0.0008. If the weight ratio is less than 1:0.0001, there may be a problem that the expected effect is minimal, and if it exceeds 1:0.002, there may be a problem that it acts as a defect.

[0083] The perovskite light-absorbing layer can be formed by blade coating or spin coating a solution containing the perovskite material represented by the above chemical formula 1 and benzylhydrazine oxalate on one surface of the first interface layer, and then heat treating. In addition, non-limiting examples of methods for forming the perovskite light-absorbing layer include a coating method and / or a vacuum deposition method, and the coating method can be a gravure coating method, a bar coating method, a printing method, a spray coating method, a spin coating method, a blade coating method, a dip method, or a die coat method.

[0084] In addition, the thickness of the perovskite light-absorbing layer is not particularly limited, but may preferably have a thickness of 100 to 800 nm, more preferably 450 to 700 nm, and even more preferably 550 to 700 nm.

[0085]

[0086] The second interface layer plays a role in reducing defects in the perovskite, blocking external deterioration factors (such as moisture) to increase stability, and effectively transferring electrons to the electron transport layer by controlling the work function.

[0087] Additionally, the second interface layer may have a thickness of 0.5 nm to 10 nm, preferably 2 nm to 8 nm.

[0088] Additionally, the second interface layer may have a surface roughness RMS (Root-mean square) of 4.50 to 80.00 nm, preferably 5.00 to 50.00 nm.

[0089] In addition, methods for forming the second interface layer include a coating method and a vacuum deposition method, and methods for applying the second interface layer include a gravure coating method, a bar coating method, a printing method, a spray method, a spin coating method, a blade coating method, a dip method, and a die coat method.

[0090] Additionally, the second interface layer may include at least one selected from lithium fluoride (LiF), magnesium fluoride (MgF2), cesium fluoride (CsF), sodium fluoride (NaF), potassium fluoride (KF), aluminum fluoride (AlF3), and calcium fluoride (CaF2).

[0091]

[0092] The intermediate layer may contain a fullerene-based organic material. In this case, the fullerene-based organic material is C 60 , C 70 , may include at least one selected from PC60BM and PC70BM, preferably C 60 second Methods for forming the intermediate layer include coating, vacuum deposition, etc., and methods for applying the intermediate layer include gravure coating, bar coating, printing, spraying, spin coating, blade coating, dip coating, and die coating.

[0093] Additionally, the intermediate layer may have a thickness of 2 nm to 20 nm, preferably 10 to 15 nm.

[0094]

[0095] The electron transporting layer (ETL) is a layer that transports electrons formed in the perovskite light-absorbing layer while simultaneously blocking the movement of holes, and may include at least one selected from tin oxide (SnO2), titanium dioxide (TiO2), zinc oxide (ZnO), barium tin oxide (BaSnO3), niobium hydroxide (NbOH), and niobium pentoxide (Nb2O5).

[0096] In addition, methods for forming the electron transport layer include a coating method and / or a vacuum deposition method, and methods for applying the electron transport layer include a gravure coating method, a bar coating method, a printing method, a spray method, a spin coating method, a blade coating method, a dip method, and a die coat method.

[0097] In addition, the thickness of the electron transport layer is not particularly limited, but may preferably have a thickness of 5 to 40 nm, more preferably 15 to 35 nm.

[0098]

[0099] A transparent electrode can be formed on top of the electron transport layer through a deposition process. At this time, the deposition can be performed using a general deposition process used in the art, and preferably, the deposition process can be performed using a sputtering method under the conditions of a process temperature of 100°C or lower, an RF power of 100 to 300 W, a process pressure of 1 to 3 mTorr, and an argon (Ar) flow of 10 to 40 sccm.

[0100] In addition, the transparent electrode may be a transparent thin film on which ITO (Indium Tin Oxide), FTO (Fluorine doped Tin Oxide), ATO (Sb2O3 doped Tin Oxide), GTO (Gallium doped Tin Oxide), ZTO (tin doped zinc oxide), ZTO:Ga (gallium doped ZTO), IGZO (Indium gallium zinc oxide), IZO (Indium doped zinc oxide), or AZO (Aluminum doped zinc oxide) is deposited.

[0101] In addition, the thickness of the transparent electrode has no separate limitation, but may preferably have a thickness of 50 to 200 nm, more preferably 50 to 140 nm.

[0102]

[0103] A metal electrode can be formed by patterning a metal material on top of a transparent electrode. Specifically, the patterning process is largely composed of deposition, lithography, and etching. A metal electrode can be formed on top of a transparent electrode by laying a metal material in the form of a thin film on one surface of a substrate, printing a pattern by lithography, and then removing unnecessary parts.

[0104] At this time, the metal material may include at least one selected from Pt, Au, Ni, Cu, Ag, In, Ru, Pd, Rh, Ir, Os, C, and a conductive polymer.

[0105] Additionally, there is no separate limitation on the thickness of the metal electrode, but it may preferably have a thickness of 50 nm to 2.5 μm.

[0106]

[0107] Meanwhile, the method for manufacturing a tandem silicon / perovskite heterojunction solar cell of the present invention includes steps 1 to 3.

[0108] First, the first step of the method for manufacturing a tandem silicon / perovskite heterojunction solar cell may sequentially laminate a solar cell, a transparent conductive layer, a hole transport layer, and a first interface layer. At this time, the solar cell, the transparent conductive layer, the hole transport layer, and the first interface layer are as described above.

[0109] Specifically, a transparent conductive layer can be formed on top of a solar cell through a sputtering process. In addition, a hole transport layer can be formed on top of the transparent conductive layer through a coating method, a vacuum deposition method, or the like.

[0110] Furthermore, the first interface layer can be formed by including the step (1) of heating the hole transport layer, the step (2) of coating a P-type organic molecule SAM interface coating agent on top of the heated hole transport layer, and the step (3) of drying the coated P-type organic molecule SAM interface coating agent to form the first interface layer.

[0111] (1) The heating of the step can be performed so that the hole transport layer is heated to 40 to 100°C, preferably 40 to 80°C, more preferably 45 to 70°C, and even more preferably 50 to 60°C.

[0112] (2) The coating of the step can be performed by blade coating, slot die coating, bar coating, gravure coating, spray coating, inkjet printing or screen printing, and preferably blade coating, slot die coating or bar coating can be performed.

[0113] (2) The P-type organic molecule SAM interface coating agent of step (2) includes a PACz-based compound and a solvent, and the PACz-based compound may be included at a concentration of 0.30 mg / ml to 10.00 mg / ml. At this time, if the concentration of the PACz-based compound is less than 0.30 mg / ml, the organic molecule SAM layer may not be sufficiently formed, which may cause a problem in that the solar cell efficiency is not increased, and if the concentration of the PACz-based compound exceeds 10.00 mg / ml, the film may be coated too thickly.

[0114] In addition, the PACz compound may include at least one selected from 2-PACz (2-(9H-Carbazol-9-yl)ethyl]phosphonic acid), MeO-2PACz, Br-2PACz, Me-4PACz, MeO-4PACz, 6-PACz, and Me-6PACz. In addition, the solvent of the P-type organic molecule SAM interfacial coating agent may include at least one selected from methanol, ethanol, 1-propanol, and 1-butanol.

[0115] Step (3) is a process for drying the coating agent coated in step (2), which can be performed by natural drying, oven heat treatment, or hot plate heat treatment, but it is preferable to perform natural drying without a separate heat treatment.

[0116]

[0117] Next, the second step of the method for manufacturing a tandem silicon / perovskite heterojunction solar cell can form a perovskite light-absorbing layer on top of the first interface layer through a coating method.

[0118] The formed perovskite light-absorbing layer may include a perovskite material represented by the following chemical formula 1 and benzylhydrazine oxalate salt.

[0119] [Chemical Formula 1]

[0120] FACsPbX3

[0121] In the above chemical formula 1, X is a monovalent anion.

[0122] Specifically, the perovskite light-absorbing layer may be a mixture of the perovskite material represented by the above chemical formula 1 and benzylhydrazine oxalate in a weight ratio of 1:0.0001 to 0.002, preferably 1:0.0003 to 0.0014, and more preferably 1:0.0004 to 0.0008.

[0123] The perovskite light-absorbing layer can be formed by blade coating or spin coating a solution containing the perovskite material represented by the above chemical formula 1 and benzylhydrazine oxalate on one surface of the first interface layer, and then heat treating. In addition, non-limiting examples of methods for forming the perovskite light-absorbing layer include a coating method and / or a vacuum deposition method, and the coating method can be a gravure coating method, a bar coating method, a printing method, a spray coating method, a spin coating method, a blade coating method, a dip method, or a die coat method.

[0124]

[0125] Finally, the third step of the method for manufacturing a tandem silicon / perovskite heterojunction solar cell may sequentially form a second interface layer, an intermediate layer, an electron transport layer, a transparent electrode, and a metal electrode on top of the perovskite light-absorbing layer. At this time, the second interface layer, the intermediate layer, the electron transport layer, the transparent electrode, and the metal electrode are as described above.

[0126] The second interface layer can be formed on the perovskite light-absorbing layer by a coating method and / or a deposition method (vacuum deposition method, thermal deposition method, vacuum thermal deposition method, etc.), the intermediate layer can be formed on the second interface layer by a coating method and / or a deposition method (vacuum deposition method, thermal deposition method, vacuum thermal deposition method, etc.), the electron transport layer can be formed on the intermediate layer by a coating method and / or a vacuum deposition method, and the transparent electrode can be formed on the electron transport layer by a deposition process. In addition, the metal electrode can be formed by patterning a metal material on the transparent electrode. At this time, the coating method can be a gravure coating method, a bar coating method, a printing method, a spray coating method, a spin coating method, a blade coating method, a dip method, or a die coat method.

[0127]

[0128] Hereinafter, the present invention will be described in more detail through examples, but the following examples do not limit the scope of the present invention, and should be interpreted as helping to understand the present invention.

[0129]

[0130] Preparation Example 1: Preparation of P-type organic molecule SAM interface coating agent

[0131] A P-type organic molecule SAM interface coating agent was prepared by mixing 2-PACz (2-(9H-Carbazol-9-yl)ethyl]phosphonic acid) at a concentration of 2.75 mg / ml in 99% pure ethanol solvent.

[0132]

[0133] Example 1: Fabrication of a tandem silicon / perovskite heterojunction solar cell

[0134] (1) A silicon solar cell (thickness: 180 ㎛) doped with n or p type impurities was prepared, and the SiOx oxide film was removed by hydrofluoric acid treatment. Then, the remaining hydrofluoric acid was removed using ultrapure water. A 20 nm thick transparent conductive layer (ITO) was formed on the top of the silicon solar cell from which the oxide film was removed through a sputtering process (process conditions: process temperature 25 to 45°C, RF power 100 to 250 W, process pressure 2.2 to 2.4 mTorr, argon flow rate 10 to 40 sccm).

[0135] (2) Next, a 20 nm thick hole transport layer (NiOx) was formed on top of the transparent conductive layer through sputter vacuum deposition.

[0136] (3) Next, the hole transport layer was heated to a temperature of 50°C, and then the P-type organic molecule SAM interface coating agent prepared in Preparation Example 1 was blade-coated on top of the heated hole transport layer to an average thickness of 3.1 nm at a blade coating speed of 10 mm / s, and then naturally dried to form a first interface layer through the blade coating method.

[0137] (4) Next, a precursor solution prepared by dissolving a perovskite material represented by the following chemical formula 1-1 and benzylhydrazine oxalate salt in a mixed solution containing dimethylformamide (DMF) and dimethylpropyleneurea (N,N'-DMPU) was blade-coated on the upper portion of the first interfacial layer, followed by heat treatment at 150°C for 10 minutes and then heat treatment at 115°C for 20 minutes to form a perovskite light-absorbing layer containing benzylhydrazine oxalate with a thickness of 600 nm and having a perovskite crystal structure. At this time, the precursor solution contained a perovskite material represented by the following chemical formula 1-1 and benzylhydrazine oxalate salt in a weight ratio of 1:0.0005.

[0138] [Chemical Formula 1-1]

[0139] FACsPb(I a Br b )3

[0140] In the above chemical formula 1-1, a and b have a molar ratio of 8:2.

[0141] (5) Next, a second interface layer (LiF) with an average thickness of 3.1 nm was formed on top of the perovskite light-absorbing layer through vacuum thermal evaporation.

[0142] (6) Next, C is deposited on the upper part of the second interface layer through thermal evaporation. 60 Fullerene (C 60 fullerene) was deposited to form an intermediate layer with an average thickness of 13 nm.

[0143] (7) Next, a SnO2 nano colloidal solution was spin-coated on the upper part of the intermediate layer to form an electron transport layer (SnO2) with a thickness of 15 nm.

[0144] (8) Next, a transparent electrode (ITO) with a thickness of 70 nm was formed on the upper portion of the electron transport layer through a sputtering process (process conditions: process temperature 95 to 98°C, RF power 100 to 200 W, process pressure 2.2 to 2.4 mTorr, argon flow rate 10 to 40 sccm).

[0145] (9) Finally, 1X10 silver (Ag) is added to the top of the transparent electrode. -7 A tandem silicon / perovskite heterojunction solar cell was manufactured in the form of a silicon solar cell, a transparent conductive layer, a hole transport layer, a first interface layer, a perovskite light-absorbing layer, a second interface layer, an intermediate layer, an electron transport layer, a transparent electrode, and a metal electrode sequentially stacked by depositing the metal electrode at a thickness of 100 nm at a pressure of 10 torr.

[0146]

[0147] Comparative Example 1: Fabrication of a Tandem Silicon / Perovskite Heterojunction Solar Cell

[0148] A tandem silicon / perovskite heterojunction solar cell was manufactured using the same method as in Example 1. However, unlike Example 1, the precursor solution used to form the perovskite light-absorbing layer was manufactured by dissolving the perovskite material represented by Chemical Formula 1-1 in a mixed solution containing dimethylformamide (DMF) and dimethylpropyleneurea (N,N'-Dimethylpropyleneurea, DMPU).

[0149]

[0150] Comparative Example 2: Fabrication of a Tandem Silicon / Perovskite Heterojunction Solar Cell

[0151] A tandem silicon / perovskite heterojunction solar cell was manufactured using the same method as in Example 1. However, unlike Example 1, the precursor solution used to form the perovskite light-absorbing layer was manufactured by dissolving the perovskite material represented by Chemical Formula 1-1 and benzylhydrazine hydrochloride in a mixed solution containing dimethylformamide (DMF) and dimethylpropyleneurea (N,N'-Dimethylpropyleneurea, DMPU). At this time, the precursor solution contained the perovskite material represented by Chemical Formula 1-1 and benzylhydrazine hydrochloride in a weight ratio of 1:0.0005.

[0152]

[0153] Example 2: Fabrication of a tandem silicon / perovskite heterojunction solar cell

[0154] A tandem silicon / perovskite heterojunction solar cell was manufactured using the same method as in Example 1. However, unlike Example 1, the precursor solution used to form the perovskite light-absorbing layer contained the perovskite material represented by the chemical formula 1-1 and benzylhydrazine oxalate in a weight ratio of 1:0.0002.

[0155]

[0156] Example 3: Fabrication of a tandem silicon / perovskite heterojunction solar cell

[0157] A tandem silicon / perovskite heterojunction solar cell was manufactured using the same method as in Example 1. However, unlike Example 1, the precursor solution used to form the perovskite light-absorbing layer contained the perovskite material represented by the chemical formula 1-1 and benzylhydrazine oxalate in a weight ratio of 1:0.0017.

[0158]

[0159] Experimental Example 1: Evaluation of Solar Cell Performance and Long-Term Storage Stability

[0160] For each of the tandem silicon / perovskite heterojunction solar cells manufactured in Examples 1 to 3 and Comparative Examples 1 to 2, the efficiency was measured using a solar simulation device and a JV Wavelabs device, and the initial JV curve was used. After storing the cells in an atmospheric pressure desiccator for 30 days, the JV curve was measured to measure the change in solar cell characteristics after aging, which is shown in Table 1 below.

[0161]

[0162]

[0163] As can be seen in Table 1 above, it was confirmed that the tandem silicon / perovskite heterojunction solar cells manufactured in Examples 1 to 3 had higher long-term storage stability than the tandem silicon / perovskite heterojunction solar cell manufactured in Comparative Example 1.

[0164]

[0165] The above illustrates and describes specific embodiments. However, the invention is not limited to the aforementioned embodiments, and those skilled in the art will readily appreciate that various modifications and implementations can be made without departing from the spirit and scope of the invention as set forth in the claims below.

Claims

1. A heterojunction solar cell in which a solar cell, a transparent conductive layer, a hole transport layer, a perovskite light-absorbing layer, an electron transport layer, a transparent electrode, and a metal electrode are sequentially laminated, A tandem silicon / perovskite heterojunction solar cell, characterized in that the perovskite light-absorbing layer comprises a perovskite material represented by the following chemical formula 1 and benzylhydrazine oxalate salt. [Chemical Formula 1] FACsPbX3 In the above chemical formula 1, X is a monovalent anion.

2. In paragraph 1, A tandem silicon / perovskite heterojunction solar cell characterized in that the perovskite light-absorbing layer comprises a perovskite material represented by the chemical formula 1 and benzylhydrazine oxalate in a weight ratio of 1:0.0001 to 0.

002.

3. In paragraph 1, A tandem silicon / perovskite heterojunction solar cell, characterized in that the perovskite light-absorbing layer has an average thickness of 450 to 700 nm.

4. In paragraph 1, A tandem silicon / perovskite heterojunction solar cell characterized in that it further comprises a first interface layer between the hole transport layer and the perovskite light absorption layer.

5. In paragraph 4, A tandem silicon / perovskite heterojunction solar cell, characterized in that the first interface layer comprises a P-type organic molecule SAM interface coating agent.

6. In paragraph 4, A tandem silicon / perovskite heterojunction solar cell, characterized in that the first interface layer has a thickness of 0.5 nm to 10 nm.

7. In paragraph 1, A tandem silicon / perovskite heterojunction solar cell characterized in that it further comprises a second interface layer between the perovskite light-absorbing layer and the electron transport layer.

8. In paragraph 7, A tandem silicon / perovskite heterojunction solar cell characterized in that the second interface layer comprises at least one selected from lithium fluoride (LiF), magnesium fluoride (MgF2), cesium fluoride (CsF), sodium fluoride (NaF), potassium fluoride (KF), aluminum fluoride (AlF3), and calcium fluoride (CaF2).

9. In paragraph 7, A tandem silicon / perovskite heterojunction solar cell, characterized in that the second interface layer has a thickness of 0.5 nm to 10 nm.

10. In paragraph 7, A tandem silicon / perovskite heterojunction solar cell characterized in that it further includes an intermediate layer between the second interface layer and the electron transport layer.

11. In paragraph 10, A tandem silicon / perovskite heterojunction solar cell characterized in that the intermediate layer comprises a fullerene series organic material.

12. The first step of sequentially stacking a solar cell, a transparent conductive layer, a hole transport layer, and a first interface layer; A second step of forming a perovskite light-absorbing layer on top of the first interface layer through a coating method; and A third step of sequentially forming a second interface layer, an intermediate layer, an electron transport layer, a transparent electrode, and a metal electrode on top of the perovskite light-absorbing layer; A method for manufacturing a tandem silicon / perovskite heterojunction solar cell, characterized in that the perovskite light-absorbing layer comprises a perovskite material represented by the following chemical formula 1 and benzylhydrazine oxalate salt. [Chemical Formula 1] FACsPbX3 In the above chemical formula 1, X is a monovalent anion.

13. In paragraph 12, A method for manufacturing a tandem silicon / perovskite heterojunction solar cell, characterized in that the coating method is a gravure coating method, a bar coating method, a printing method, a spray coating method, a spin coating method, a blade coating method, a dip method, or a die coat method.

14. In paragraph 12, A method for manufacturing a tandem silicon / perovskite heterojunction solar cell, characterized in that the perovskite light-absorbing layer is a mixture of the perovskite material represented by the chemical formula 1 and benzylhydrazine oxalate in a weight ratio of 1:0.0001 to 0.

002.

15. In the 12th paragraph, the first interface layer Step (1) of heating the above hole transport layer; (2) step of coating a P-type organic molecule SAM interface coating agent on the upper part of the heated hole transport layer; and Step (3) of drying the coated P-type organic molecule SAM interfacial coating agent to form a first interfacial layer; A method for manufacturing a tandem silicon / perovskite heterojunction solar cell, characterized in that it is formed by including.

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