Perovskite solar cell and method for manufacturing the same

Abstract

To provide a perovskite solar cell having a compound with perovskite structure that is more stabilized than conventional compounds, and a method for manufacturing the perovskite solar cell.SOLUTION: A perovskite solar cell 10 includes a first electrode 14, an electron transport layer 16, a photoelectric conversion layer 18, a hole transport layer 20, and a second electrode 22 which are laminated in this order on a substrate 12. The photoelectric conversion layer 18 is a mixed pn semiconductor layer composed of an n-type semiconductor and a p-type semiconductor. The p-type semiconductor includes a compound having perovskite structure. An example of a compound having perovskite structure is HC(NH2)2PbI3 (also referred to as FAPbI3). An element with multiple ionic valences and charge degrees of freedom is added to the FAPbI3.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a perovskite solar cell using a compound having a perovskite structure and a method for producing the same. [Background technology]

[0002] Solar cells using compounds with a perovskite structure are currently attracting attention. CH3NH3PbI3 is known as a representative compound with a perovskite structure. However, there are problems with perovskite compound crystals, such as the decomposition of CH3NH3 due to elimination of CH3NH3, and the destabilization of the compound crystals themselves when other elements are introduced into the Pb site to reduce the toxic Pb.

[0003] The solar cell disclosed in Patent Document 1 below has a perovskite structure. Patent Document 1 describes that durability can be improved by covering the solar cell with a barrier layer. However, covering the solar cell with a barrier layer does not resolve the instability of the perovskite compound crystal itself. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2022-152729 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide a perovskite solar cell comprising a compound having a perovskite structure that is more stable than conventional compounds, and a method for producing the same. [Means for solving the problem]

[0006] The perovskite solar cell of the present invention comprises a substrate, a first electrode on the substrate, an electron transport layer on the first electrode, a layer of an n-type semiconductor formed in a mesoporous state on the electron transport layer, a layer of a perovskite compound formed in gaps between the n-type semiconductor, a hole transport layer formed on the layer of the perovskite compound, and a second electrode formed on the hole transport layer. The perovskite compound may contain HC(NH)PbI (also referred to as FAPbI) incorporating HC(NH)PbI, wherein a portion of the FA, a portion of the Pb, or both, may be substituted with an element having multiple ionic valences.

[0007] The method for manufacturing a perovskite solar cell of the present invention includes the steps of: preparing a substrate; forming a first electrode on one surface of the substrate; forming an electron transport layer on the first electrode; forming a compound having an n-type semiconductor and a perovskite structure on the electron transport layer to form a photoelectric conversion layer; forming a hole transport layer on the photoelectric conversion layer; and forming a second electrode on the hole transport layer. The formation of the compound having a perovskite structure may include the step of adding elements having multiple ionic valences to a precursor solution of FAPbI3. [Effects of the Invention]

[0008] According to the present invention, a portion of the FA or Pb in a compound having a perovskite structure is substituted with an element having a high degree of charge freedom and multiple ionic valences, thereby increasing the stability of the compound crystal having a perovskite structure. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram illustrating a schematic configuration of a perovskite solar cell. [Figure 2] X-ray diffraction patterns of FA1-xCuxPbI3 crystals with Cu+ added and varying the FA / Pb ratio. [Figure 3]This is an X-ray diffraction pattern of Ge-doped FA0.95Cs0.05Pb1-xGexI3 perovskite crystal. DETAILED DESCRIPTION OF THE INVENTION

[0010] The perovskite solar cell and the method for producing the same of the present invention will be described with reference to the drawings.

[0011] The perovskite solar cell 10 of the present invention has a first electrode 14, an electron transport layer 16, a photoelectric conversion layer 18, a hole transport layer 20, and a second electrode 22 stacked in this order on a substrate 12.

[0012] The substrate 12 is a transparent substrate made of glass, resin, organic material, or the like. A first electrode 14 is formed on one surface of the substrate 12, and the other surface serves as a light incidence surface. An anti-reflection film may be provided on the other surface to increase the efficiency of light incidence on the photoelectric conversion layer 18. The substrate 12 may be flexible.

[0013] The first electrode 14 is a transparent electrode such as FTO (Fluorine-doped Tin Oxide), ITO (Indium Tin Oxide), ZnO (Zinc Oxide), AZO (Aluminum-doped Zinc Oxide), GZO (Gallium-doped Zinc Oxide), or IGZO (Indium-Gallium-doped Zinc Oxide). The first electrode 14 serves as a cathode. There may be one first electrode 14 per substrate 12, or the first electrode 14 may be divided into multiple electrodes.

[0014] The electron transport layer 16 is made of a transparent conductive material such as titanium oxide (TiO2) or zinc oxide (ZnO). The layer thickness of the electron transport layer 16 is approximately 5 to 100 nm, for example, approximately 30 nm. The electron transport layer 16 is a layer that improves the flow of electrons and increases the conversion efficiency. In addition, the electron transport layer 16 prevents the p-type semiconductor layer of the n-type and p-type semiconductors that make up the photoelectric conversion layer 18 from shorting to the first electrode 14.

[0015] The metal atom positions of the electron transport layer 16 may be doped with atoms having a high valence. This doping improves the photoelectric conversion efficiency. When the electron transport layer 16 is made of TiO2, Ti 4+ Nb, which has a higher valence than 5+ , V 5+ , Ta 5+ When the electron transport layer 16 is made of ZnO, Zn 2+ Ga, which has a higher valence than 3+ , In 3+ , Al 3+ Doping etc.

[0016] The photoelectric conversion layer 18 is a pn semiconductor mixed layer composed of n-type and p-type semiconductors. The n-type semiconductor is mesoporous (porous) and has many irregularly shaped gaps (microscopic spaces). The p-type semiconductor fills these gaps. This increases the contact area between the n-type and p-type semiconductors, improving conversion efficiency (power generation efficiency).

[0017] The mesoporous n-type semiconductor is made of TiO2 or ZnO. The layer thickness of the n-type semiconductor is about 0 to 1000 nm, preferably about 0 to 300 nm. As the layer thickness increases, the contact area between the n-type and p-type semiconductors increases, increasing the conversion efficiency but decreasing manufacturing efficiency. Within the above layer thickness range, an optimum thickness is selected for both conversion efficiency and manufacturing efficiency.

[0018] Similar to the electron transport layer 16, the metal atom sites of the mesoporous n-type semiconductor may be doped with atoms having a high valence. The doping atoms are the same as those in the electron transport layer 16 described above.

[0019] The p-type semiconductor includes a compound having a perovskite structure. An example of a compound having a perovskite structure is HC(NH2)2PbI3 (also written as FAPbI3). It is preferable that an element having a plurality of ionic valences and a degree of charge freedom is added to the FAPbI3. An example of an element having a degree of charge freedom is Cu (Cu + , Cu 2+ ), Cd(Cd + , Cd 2+), Ge(Ge 2+ , Ge 4+ ), Sn(Sn 2+ , Sn 4+ ), Pd(Pd 2+ , Pd 4+ ), Pt(Pt 2+ , Pt 4+ ), Co(Co 2+ , Co 3+ ), Ni(Ni 2+ , Ni 3+ ), Cr(Cr 2+ , Cr 3+ ), Fe(Fe 2+ , Fe 3+ ), V(V 2+ , V 3+ ), Mn(Mn 2+ , Mn 3+ ), Eu(Eu 2+ ,EU 3+ ), Gd(Gd 2+ , Gd 3+ ), Nd(Nd 2+ , Nd 3+ ), Yb(Yb 2+ , Yb 3+ ), Sm(Sm 2+ , Sm 3+ ) etc.

[0020] In compounds having a perovskite structure, some or all of the FA may be substituted with Cu, some or all of the Pb may be substituted with Cu, or both may be substituted. + ) incorporated into FA x Cu 1-x PbI3, divalent copper ions (Cu 2+ ) incorporated into FAPb x Cu 1-x Even if a part of FA is volatilized or desorbed, Cu is not present in that part. + The compound crystal with a perovskite structure is stabilized. 2+ The inclusion of Pb reduces the toxic Pb content and stabilizes the compound crystals with a perovskite structure.

[0021] In compounds with a perovskite structure, part or all of the Pb may be replaced with Ge. For example, FA in which Cs is also added to form a compound with a perovskite structure may be used. x Cs 1-x Pb y Ge 1-y One example is the perovskite structure of I3. By substituting part of the Pb with Ge, the toxic Pb is reduced and compounds with the perovskite structure become stable.

[0022] Although the replacement of part of FA or Pb with Cu and part of Pb with Ge has been described, both may be replaced at the same time. Furthermore, the elements are not limited to Cu and Pb, and the above-mentioned elements with a degree of charge freedom may also be used.

[0023] The hole transport layer 22 is a layer for improving the flow of holes and increasing the conversion efficiency. Examples of materials for the hole transport layer 22 include Spiro-OMeTAD (abbreviation for 2,2',7,7'-tetrakis-(N,N-di-pmethoxyphenylamine)9,9'-spirobifluorene). Carbon paste, poly-3-hexylthiophene (P3HT), poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (commonly known as PEDOT:PSS), CuSCN, and CsSnI3 may also be used. The thickness of the hole transport layer 22 is approximately 5 to 100 nm. A thickness of less than 5 nm may result in insufficient coverage, while a thickness of more than 100 nm may result in increased electrical resistance. To prevent deterioration of the layers of Spiro-OMeTAD and the compound having a perovskite structure, it is preferable to seal the perovskite solar cell 10 with a cover glass, ethylene vinyl acetate copolymer resin (EVA), polyvinyl butyral (PVB), silicone resin, or the like.

[0024] The hole transport layer 22 may contain phthalocyanine, naphthalocyanine, subphthalocyanine, polysilane, NiO, CuO, Cu2O, V2O5, WO instead of Spiro-OMeTAD. x or MoO xPhthalocyanine, naphthalocyanine, subphthalocyanine, polysilane, NiO, CuO, Cu2O, V2O5, WO, etc. can also be used. x or MoO x are more stable in air than Spiro-OMeTAD and can withstand long-term use in air. In addition, phthalocyanine, naphthalocyanine, subphthalocyanine, and polysilane are cheaper than Spiro-OMeTAD, which reduces the cost of the perovskite solar cell 10.

[0025] The second electrode 24 is an anode. A conductor having a work function of 5.2 eV or less, such as Au, Ag, Cu, Al, or C, can be used for the second electrode 24. The layer thickness of the second electrode 24 may be 100 nm or more, for example, about 150 to 300 nm.

[0026] Next, a method for manufacturing the perovskite solar cell 10 will be described. (1) A transparent substrate 12 such as glass is prepared. This preparation includes cutting the substrate 12 into a desired shape and cleaning it.

[0027] (2) A first electrode 14 is formed on one surface of the substrate 12. A transparent electrode such as FTO or ITO is formed by sputtering, thermal evaporation, spray pyrolysis, or the like. If necessary, the transparent electrode is patterned (etched) into a desired shape.

[0028] (3) An electron transport layer 16 is formed on the first electrode 14. For example, TiO x A solution obtained by stirring a precursor solution and a solvent is dropped onto the substrate, spin-coated, and heat-treated to form a TiO2 electron transport layer 16. The electron transport layer 16 has a dense structure, not a mesoporous structure, and compounds with a perovskite structure do not penetrate into the layer.

[0029] TiO xTitanium diisopropoxide bis(acetyl acetonate) (diisopropoxytitanium(IV) bis(4-oxo-2-penten-2-olate)) can be used as the precursor solution, but solutions containing Ti such as titanium isopropoxide (tetraisopropyl orthotitanate) or TiO x Sol-gel solutions can also be used. 1-butanol is used as the solvent, and TiO x The precursor solution and the solvent are stirred and added dropwise.

[0030] (4) An n-type semiconductor layer of the photoelectric conversion layer 18 is formed on the electron transport layer 14. The n-type semiconductor layer has a mesoporous structure. A solution containing TiO2 is spin-coated and heat-treated to form an n-type semiconductor layer of mesoporous TiO2.

[0031] The TiO2 solution is prepared by adding ultrapure water to TiO2 powder and a polymer compound, stirring the mixture, and then adding an organic compound and a surfactant. Examples of polymer compounds include polyethylene glycol and ethyl cellulose, and examples of organic compounds include acetyl acetone. A nonionic surfactant, such as a type of polyoxyethylene alkyl phenyl ether, can be used as the surfactant, and a surfactant containing a compound such as polyethylene glycol p-(1,1,3,3-tetramethylbutyl)-phenyl ether can be used.

[0032] (5) A p-type semiconductor layer of the photoelectric conversion layer 18 is formed. The p-type semiconductor layer contains a compound having a perovskite structure and is formed in the gaps in the n-type semiconductor layer and on top of it. The n-type semiconductor layer is mesoporous and has irregular gaps within the layer. A perovskite compound precursor solution is spin-coated and heat-treated to form a compound having a perovskite structure in the gaps in the n-type semiconductor layer and on top of it.

[0033] The spin-coated material is a precursor solution for forming FAPbI3, a compound with a perovskite structure, to which elements with multiple ionic valences and charge degrees of freedom are added. The added elements include rare earth elements or metal elements. These elements include Cu, Cd, Ge, Sn, Pd, Pt, Co, Ni, Cr, Fe, V, Mn, Eu, Gd, Nd, Yb, and Sm. The precursor solution materials include HC(NH2)2I, CH5N2I, CH5N·HCI, CH3CH2NH3I, C(NH2)3I, (CH3)2NH2I, PbI2, PbCl2, and halides of the added elements.

[0034] It is preferable to spin coat the solution multiple times. The perovskite structure compound penetrates into the n-type semiconductor layer, and multiple spin coatings allow the compound to penetrate gradually, ensuring that the perovskite structure compound is formed in the n-type semiconductor layer. After one or more spin coatings, a heat treatment is performed. The heat treatment temperature is approximately 50 to 300°C.

[0035] (6) Forming the hole transport layer 20. The hole transport layer 20 is formed by spin coating a solution containing the hole transport material Spiro-OMeTAD. The hole transport layer 20 may also be formed by depositing the hole transport layer material using other lamination methods, such as screen printing, doctor blade, spraying, plating, or vapor deposition.

[0036] (7) Forming the second electrode 22. A conductor such as Au is vapor-deposited using a vapor deposition device to form the second electrode 22. The electrode may be formed by spin coating, screen printing, plating, or other methods. The manufacture of the perovskite solar cell 10 is completed when the second electrode 22 is formed. If necessary, the perovskite solar cell 10 may be covered or sealed, and wiring may be connected to each of the electrodes 14, 22.

[0037] [Example 1] An example will be described in which Cu is added to FAPbI3, a compound having a perovskite structure. The perovskite solar cell was manufactured as follows.

[0038] A fluorine-doped SnO2 (FTO) substrate was prepared, with a first electrode 14 formed on a substrate 12. After ultrasonically cleaning the fluorine-doped SnO2 (FTO) substrate using acetone and methanol, the FTO substrate was dried with nitrogen gas and irradiated with ultraviolet (UV) light for 15 minutes.

[0039] To form the electron transport layer 16, a compact-TiO precursor solution (0.15, 0.30 M) was prepared using titanium diisopropoxide bis(acetyl acetonate) (Sigma-Aldrich, 0.055, 0.11 mL) and 1-butanol (Nacalai Tesque, 1 mL). The 0.15 M compact-TiO precursor solution was spin-coated (3000 rpm, 30 s) onto the fluorine-doped SnO (FTO) substrate and annealed at 125 °C for 5 minutes on a hot plate. A 0.30 M compact-TiO precursor solution was spin-coated under the same conditions and annealed at 125 °C for 5 minutes on a hot plate. The compact-TiO film was then sintered in an electric furnace at 450 °C for 30 minutes.

[0040] To form the n-type semiconductor layer of the photoelectric conversion layer 18, a mesoporous-TiO precursor solution was prepared by stirring TiO nanoparticles (Nippon Aerosil Co., Ltd., P-25, 200 mg) and poly(ethylene glycol) (Nacalai Tesque, Inc., PEG #20000, 20 mg) in 1 mL of ultrapure water, followed by the addition of acetylacetone (Fujifilm Wako Pure Chemical Industries, Ltd., 20 mL) and a surfactant (Sigma-Aldrich, Triton X-100, 10 mL). The mesoporous-TiO precursor solution, which had been stirred for 24 hours, was spin-coated (5000 rpm, 30 s) onto a compact-TiO film that had been UV-irradiated for 15 minutes and then sintered in an electric furnace at 450 °C for 30 minutes to form a mesoporous-TiO film.

[0041] To form the p-type semiconductor layer of the photoelectric conversion layer 18, a perovskite precursor solution was prepared using HC(NH)I (Sigma-Aldrich) and PbI (Sigma-Aldrich). The solvent used was a mixture of dimethyl sulfoxide-dimethylformamide (DMF, Nacalai Tesque, 0.4 mL) and dimethyl sulfoxide (DMSO, Tokyo Chemical Industry, 0.1 mL). CuI (Sigma-Aldrich) was added to the perovskite precursor solution. The perovskite precursor solution was spin-coated (2000 rpm, 60 s) onto a mesoporous-TiO film that had been UV-irradiated for 15 minutes. The perovskite precursor solution was spin-coated three times using the air blow method and annealed on a hot plate at 150 °C for 20 minutes.

[0042] To form the hole transport layer 20, a Spiro-OMeTAD solution was prepared by dissolving 2,2',7,7'-Tetrakis(N,N-di-p-methoxyphenylamino)-9,9'-spirobifluorene (Fujifilm Wako Pure Chemical Industries, Ltd., 36.1 mg) in chlorobenzene (Fujifilm Wako Pure Chemical Industries, Ltd., 0.5 mL). Li-TFSI and FK209 solutions were prepared by dissolving lithium bis(trifluoromethylsulfonyl)imide (Tokyo Chemical Industry Co., Ltd., 260 mg) or tris[2-(1Hpyrazol-1-yl)-4-tert-butyl pyridine]cobalt(III) tri[bis(trifluoromethane)sulfonimide] (Sigma-Aldrich, 188 mg) in acetonitrile (Nacalai Tesque, Inc., 0.5 mL), respectively. The Spiro-OMeTAD solution was mixed with 0.010 mL of Li-TFSI solution, 0.004 mL of FK209 solution, and 0.018 mL of 4-tertbutylpyridine (Sigma-Aldrich) and stirred for 4 h. The dopant-containing Spiro-OMeTAD solution was then spin-coated (4000 rpm, 30 s) onto the perovskite film.

[0043] Au was vacuum-deposited to form the second electrode 22. The device fabrication process other than this vacuum deposition was carried out in air.

[0044] The proportions of materials used in the above manufacturing process are shown in Table 1. In Table 1, [A + ] is [FA + ] and [Cu + ], the sum of the concentrations of [B 2+ ] is [Pb 2+ For example, a perovskite film labeled FA1.5+Cu12.5% ​​corresponds to the concentration of the precursor solution with a composition of [FA + ] / [Pb 2+ ]=1.5, ([FA + ]+[Cu + ]) / [Pb 2+]=1.625.

[0045] [Table 1]

[0046] This section explains the details of the perovskite compound crystal manufactured by adding Cu to FAPbI3. First-principles calculations were performed to evaluate the crystal structure and electronic state. FAPbI3 was used as the reference composition, and FA in which some of the FA at the A site was missing was used. 0.875 PbI3, monovalent copper ions (Cu + ) incorporated into FA 0.875 Cu 0.125 PbI3, divalent copper ions (Cu 2+ ) incorporated into FAPb 0.875 Cu 0.125 A crystal structure model of I3 perovskite was constructed. A 2x2x2 supercell was used for the crystal structure model, and calculations were performed for the band structure, partial density of states, electron density distribution, and dielectric function. Ultrasoft pseudopotentials were used for first-principles calculations, and kinetic energy cutoffs for the wave function and charge density were selected from the ranges of 40-45 and 160-260 Ry (Rydberg) appropriate for each composition. The k-point was calculated under a 4x4x4 condition. The same conditions were also applied to Born-Oppenheimer molecular dynamics calculations to determine the diffusion coefficients, tracking the self-diffusion behavior of ions.

[0047] Table 2 shows the number of defects (V FA ), the total energy upon Cu introduction (E tot ), band gap (E g ) and the self-diffusion coefficient (D). 0.875 PbI3, FA 0.875 Cu 0.125 The total energies of the PbI3 perovskite crystal are -3744, -3648, and -3771 eV / cell, respectively, and the A-site contains monovalent copper ions (Cu + ) incorporated into FA 0.875 Cu0.125 PbI3 showed the lowest total energy. Furthermore, the band gap changed with the introduction of Cu, indicating that it is possible to control the band gap of perovskite crystals by substituting FA cations. 1+ The self-diffusion coefficient (D) is also minimized by the introduction of hydroxyl groups, suggesting that atomic migration is suppressed and stability can be maintained.

[0048] [Table 2]

[0049] The calculation results of the electron density distribution show that the electron density is high around Pb and I, and charge carriers are generated by electron transition between the Pb-p orbital and the Ip orbital. It was confirmed that when Cu is placed in the A site, the electron density is high around Cu. Therefore, the interaction between Cu in the A site and the Pb-I frame may affect the stability of the crystal structure, the diffusion of I-ions, and the charge transfer in the Pb-I frame. Based on these calculation results, the FA:Cu=87.5:12.5 is 0.875 Cu 0.125 PbI3 is believed to be stable, and perovskite solar cells were fabricated using the method described above.

[0050] Figure 2 shows the FA with Cu added while changing the FA / Pb ratio. 1-x Cu x This is the X-ray diffraction pattern of PbI3 crystals. For example, the perovskite film labeled FA1.5+Cu12.5% ​​has a precursor solution composition of [FA + ] / [Pb 2+ ]=1.5, ([FA + ]+[Cu + ]) / [Pb 2+ ]=1.625.

[0051] Table 3 shows the composition of the precursor solution used to form the perovskite film, and the ratio of the intensities (I) of the X-ray diffraction peaks corresponding to the photoactive α phase and impurity phases (1D phase, δ phase, PbI2) analyzed from the X-ray diffraction patterns of the perovskite crystalline thin films actually obtained.

[0052] [Table 3]

[0053] For additive-free FAPbI3 films, the intensity of the X-ray diffraction peaks corresponding to the photoactive α phase was very low for FA1.375 and 1.625, while the X-ray diffraction peaks corresponding to the photoinactive δ phase were confirmed. While the α phase diffraction peaks were observed for FA1.875, the diffraction peaks corresponding to the one-dimensional (1D) phase were also observed. With the addition of Cu, the diffraction peaks corresponding to PbI2 were observed for FA1.25. With the addition of Cu and increasing the FAI content, for example, the diffraction peak intensities corresponding to the δ phase and PbI2 decreased, promoting the formation of the α phase for FA1.5–1.75 (Figure 2). Furthermore, the intensity of the diffraction peaks corresponding to the 1D phase remained almost unchanged with increasing FA content. With the addition of Cu, the X-ray diffraction peaks corresponding to the 1D and δ phases disappeared, and a clear diffraction peak corresponding to the α phase was observed, indicating the formation of a cubic α-FAPbI3 structure.

[0054] As mentioned above, Cu 1+ When Cu was introduced into the FA site, the formation of the α phase was confirmed by X-ray diffraction experiments. 1+ and Cu 2+ It was found that there is a possibility of stabilizing the crystal structure by charge compensation because there are charge degrees of freedom.

[0055] [Example 2] An example will be described in which Ge is added to a compound having a perovskite structure. The manufacturing process of this perovskite solar cell differs from that of Example 1 in the manufacturing process of the compound having a perovskite structure. The differences will be described, and the same explanations will be omitted.

[0056] To prepare the perovskite compound for forming the p-type semiconductor layer of the photoelectric conversion layer 18, HC(NH)I (FAI, Sigma Aldrich), PbI (Sigma Aldrich), GeI (Sigma Aldrich), and CHN·HCl (MACl, Fujifilm Wako Pure Chemical Industries, 13.5 mg) were dissolved in dimethyl sulfoxide-dimethylformamide (DMF, Nacalai Tesque, 0.4 mL) and dimethyl sulfoxide (DMSO, Tokyo Chemical Industry, 0.1 mL). Then, CsI (Daiichi Kigenso Kagaku Kogyo, 130 mg) was dissolved in 0.5 mL of a 4:1 DMF:DMSO mixture to a concentration of 1.0 M. 6.5 μL of this solution was added dropwise to the perovskite solution and stirred overnight at 60 °C to prepare a perovskite precursor solution.

[0057] The above perovskite solution was dropped onto the mesoporous-TiO2 film (n-type semiconductor layer) and the film was formed at a rotation speed of 4000 rpm for 30 seconds. Then, the perovskite solution was dropped again and spin-coated. Ethyl acetate (200 μL) was dropped as an antisolvent solution 10 seconds before the end of the rotation. Then, the cell was heat-treated on a hot plate at 150 °C for 3 minutes. The fabricated cell was stored at a temperature of 22 °C and a humidity of 30% or less.

[0058] Except for forming the above p-type semiconductor layer, a perovskite solar cell was manufactured in the same manner as in Example 1. Table 4 shows the proportions of the materials used.

[0059] [Table 4]

[0060] The details of the perovskite solar cell with Ge added to FAPbI3 are explained below. Figure 3 shows the Ge-added FAPbI3. 0.95 Cs 0.05 Pb 1-x Ge xThe X-ray diffraction pattern of I3 perovskite crystals is shown below. When no Ge was added (0%), X-ray diffraction peaks of the optically inactive δ phase, PbI2, and 1D phase were observed, but no α phase was observed. On the other hand, as the amount of Ge added increased, the X-ray diffraction peak of the α phase gradually became stronger, and at Pb:Ge = 80-70:20-30, the X-ray diffraction peaks of the δ phase and PbI2 disappeared, and a clear X-ray diffraction peak of the α phase was obtained. Ge 2+ and Ge 4+ It was found that charge compensation of FA defects due to the charge degree of freedom may stabilize the α phase.

[0061] In the two examples, Cu and Ge were explained, but it is thought that elements with electron freedom in ionic valence can be used. For example, Cu (Cu + , Cu 2+ ), and Ge(Ge 2+ , Ge 4+ ) is an element that has a degree of freedom in ionic charge, such as europium (Eu 2+ ,EU 3+ ), gadolinium (Gd 2+ , Gd 3+ ), neodymium (Nd 2+ , Nd 3+ ), Ytterbium (Yb 2+ , Yb 3+ ), samarium (Sm 2+ , Sm 3+ ), or cadmium (Cd + , Cd 2+ ), tin (Sn 2+ , Sn 4+ ), palladium (Pd 2+ , Pd 4+ ), platinum (Pt 2+ , Pt 4+ ), cobalt (Co 2+ , Co 3+ ), Nickel (Ni 2+ , Ni 3+ ), chromium (Cr 2+ , Cr 3+ ), iron (Fe 2+ , Fe 3+ ), vanadium (V 2+ , V 3+ ), manganese (Mn2+ , Mn 3+ ) may contribute to the stabilization of FAPbI3.

[0062] In addition, the present invention can be implemented in various forms with various improvements, modifications, and changes made based on the knowledge of those skilled in the art without departing from the spirit of the present invention. [Explanation of symbols]

[0063] 10: Perovskite solar cells 12: Circuit board 14: 1st electrode 16:Electron transport layer 18: Photoelectric conversion layer 20: Hole transport layer 22:Second electrode

Claims

1. A substrate; a first electrode on the substrate; an electron transport layer on the first electrode; a mesoporous n-type semiconductor layer on the electron transport layer; a layer of a compound having a perovskite structure formed in the gaps of the n-type semiconductor; a hole transport layer formed on the layer of the perovskite structure compound; a second electrode formed on the hole transport layer; Equipped with The compound with a perovskite structure is FAPbI ３ wherein a portion of the FA, a portion of the Pb, or both, are substituted with an element having a plurality of ionic valencies.

2. FAPbI ３ 2. The perovskite solar cell of claim 1 , wherein some or all of the FA in formula (I) is substituted with Cu, some or all of the Pb is substituted with Ge or Cu, or both.

3. The perovskite solar cell of claim 2, wherein when a portion of the FA is substituted with Cu, the FA:Cu ratio is 87.5:12.

5.

4. The perovskite solar cell of claim 2, wherein when a portion of the Pb is substituted with Ge, the Pb:Ge ratio is 80-70:20-30.

5. providing a substrate; forming a first electrode on one side of the substrate; forming an electron transport layer on the first electrode; forming a compound having an n-type semiconductor and a perovskite structure on the electron transport layer to form a photoelectric conversion layer; forming a hole transport layer on the photoelectric conversion layer; forming a second electrode on the hole transport layer; Equipped with The formation of the compound having the perovskite structure is carried out by FAPbI ３ A method for manufacturing a perovskite solar cell, comprising the step of adding elements having multiple ionic valencies to a precursor solution of the compound.

6. The formation of the compound having the perovskite structure is carried out by FAPbI ３ CuI or Cu in the precursor solution ＋ adding a compound comprising FAPbI ３ In the precursor solution of GeI ２ or Ge ２＋ 6. The method for producing a perovskite solar cell according to claim 5, further comprising the step of adding a compound containing

7. FAPbI ３ 7. The method for producing a perovskite solar cell according to claim 6, wherein the step of adding CuI to the precursor solution comprises a step of substituting a part or all of FA with Cu.

8. The step of substituting a part of FA with Cu is carried out by adding [FA ＋ ] / [Pb 2＋ 8. The method for producing a perovskite solar cell according to claim 7, wherein the value of [Ratio of Ratio of ZnO to ZnO] is 1.5 to 1.

75.

9. FAPbI ３ In the precursor solution of GeI ２ The method for producing a perovskite solar cell according to claim 6 , wherein the step of adding includes a step of substituting part or all of Pb with Ge.

10. 10. The method for producing a perovskite solar cell according to claim 9, wherein the step of substituting a portion of Pb with Ge is carried out at a ratio of Pb:Ge=80-70:20-30.

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