Solar cell and method for manufacturing solar cell

Abstract

A solar cell 100 according to the present disclosure is sequentially provided with a first electrode 2, a photoelectric conversion layer 3 and a second electrode 4 in this order. The photoelectric conversion layer 3 contains: a perovskite compound which contains a first metal element and a second metal element; a first compound which contains the first metal element and a first amine material that has two or more carbon atoms; and a second compound which contains the second metal element and a second amine material that has two or more carbon atoms.

Description

[Technical Field]

[0001] The present disclosure relates to solar cells and methods for manufacturing solar cells. [Background technology]

[0002] In recent years, research and development has been progressing on solar cells (hereinafter referred to as "perovskite solar cells") that use halides having a perovskite crystal structure or a structure similar thereto (hereinafter referred to as "perovskite compounds") as photoelectric conversion materials.

[0003] Non-Patent Document 1 uses a perovskite compound represented by CH3NH3PbI3 (hereinafter referred to as MAPbI3) as a photoelectric conversion material, uses TiO2 as an electron transport material, and They disclose a solar cell that uses Spiro-OMeTAD as a hole transport material. Non-Patent Document 2 discloses a perovskite solar cell that uses a mixed perovskite material that mixes two divalent cations, tin and lead, to achieve a band gap of 1.3 eV or less for the photoelectric conversion material. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] Julian Burschka, et al., “Sequential deposition as a route to high-performance perovskite-sensitized solar cells”, Nature, vol.499, pp.316-319, 2013. [Non-patent document 2] Yuhei Ogomi, et al., “CH3NH3SnxPb(1-x)I3 Perovskite Solar Cells Covering up to 1060 nm”, The Journal of Physical Chemistry Letters, vol 5, pp.1004-1011, 2014. Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present disclosure is to provide a perovskite solar cell using a mixed perovskite material, which has a configuration suitable for improving photoelectric conversion efficiency. [Means for solving the problem]

[0006] The solar cell of the present disclosure comprises: a first electrode, a photoelectric conversion layer, and a second electrode in this order; The photoelectric conversion layer is a perovskite compound containing a first metal element and a second metal element; a first compound comprising the first metal element and a first amine material having two or more carbon atoms; a second compound comprising the second metal element and a second amine material having two or more carbon atoms; Includes: [Effects of the Invention]

[0007] The present disclosure provides a perovskite solar cell using a mixed perovskite material, which has a configuration suitable for improving photoelectric conversion efficiency. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 shows a cross-sectional view of a solar cell 100 according to an embodiment of the present disclosure. [Figure 2] FIG. 2 shows a cross-sectional view of a solar cell 200 according to an embodiment of the present disclosure. [Figure 3] FIG. 3 is a graph showing the current-voltage characteristics of the solar cells according to Example 1 and Comparative Example 1. [Figure 4] FIG. 4 is a graph plotting the open circuit voltages of the solar cells according to Example 1, Example 2, and Comparative Example 1. [Figure 5]FIG. 5 is a graph showing X-ray diffraction patterns of the photoelectric conversion layers constituting the solar cells according to Example 1 and Comparative Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0009] <Terminology> As used herein, the term "perovskite compound" refers to a perovskite crystal structure represented by the chemical formula ABX3 and structures having similar crystals, where A is a monovalent cation, B is a divalent cation, and X is a halogen anion.

[0010] As used herein, the term "mixed perovskite compound" refers to a perovskite compound of the above formula ABX3, where B contains two or more divalent cations. For example, a "tin-lead mixed perovskite compound" refers to a perovskite compound containing both tin and lead as divalent cations.

[0011] <Knowledge that forms the basis of this disclosure> Tandem solar cells are solar cells that are made up of multiple photoelectric conversion materials with different bandgaps. Tandem solar cells are able to absorb light over a wider range than solar cells that use a single photoelectric conversion material, resulting in solar cells with higher conversion efficiency.

[0012] When perovskite compounds are used in tandem solar cells, a typical structure is one in which a solar cell (i.e., a top cell) using a perovskite compound with a wide band gap (e.g., a band gap greater than 1.7 eV) is stacked with a solar cell (i.e., a bottom cell) using a perovskite compound with a narrow band gap (e.g., a band gap less than 1.3 eV).

[0013] Known perovskite compounds with narrow band gaps include those containing multiple divalent cations at the B site. Non-Patent Document 2 discloses a perovskite solar cell that uses a mixture of two divalent cations, tin and lead, to achieve a band gap of less than 1.3 eV for the photoelectric conversion material.

[0014] However, when a mixture of divalent cations is used, it is difficult to achieve high conversion efficiency compared to when only one divalent cation is used. This is because when multiple divalent cations are used, a mechanism for suppressing recombination and material degradation is required for each material constituting the B site. In the example described in Non-Patent Document 2, a cell using a mixture of tin and lead achieved less than half the conversion efficiency of a cell using lead alone.

[0015] In light of these findings, the present inventors conducted extensive research and found that in solar cells using a mixed perovskite compound as a photoelectric conversion material, it is possible to improve the photoelectric conversion efficiency by forming individual compounds of each cation constituting the B site and an amine material having two or more carbon atoms and incorporating these compounds into the photoelectric conversion layer.

[0016] <Embodiments of the present disclosure> A solar cell according to an embodiment of the present disclosure includes, in this order, a first electrode, a photoelectric conversion layer, and a second electrode. The photoelectric conversion layer includes a perovskite compound including a first metal element and a second metal element, a first compound, and a second compound. The first compound includes the first metal element and a first amine material having two or more carbon atoms. The second compound includes the second metal element and a second amine material having two or more carbon atoms.

[0017] According to the above configuration, factors that reduce the photoelectric conversion efficiency, such as recombination and material degradation, can be suppressed for each of the first metal element and the second metal element in the perovskite compound in the photoelectric conversion layer. As a result, the solar cell according to this embodiment can improve the photoelectric conversion efficiency in a solar cell that uses a mixed perovskite compound as the photoelectric conversion material.

[0018] 1 shows a cross-sectional view of a solar cell 100 according to a first embodiment. The solar cell 100 is an example (first configuration example) of a solar cell according to the present disclosure.

[0019] The solar cell 100 comprises a substrate 1, a first electrode 2, a photoelectric conversion layer 3, and a second electrode 4 in this order.

[0020] The photoelectric conversion layer 3 contains a mixed perovskite compound. The mixed perovskite compound has, for example, the chemical formula ABX3 and contains both cations of a first metal element and a second metal element in the B site.

[0021] The photoelectric conversion layer 3 further includes a first compound containing a first metal element and a first amine material having two or more carbon atoms, and a compound of a second metal element and a second amine material having two or more carbon atoms. Here, the first amine material and the second amine material may be amine materials having different compositions from each other, or may be amine materials having the same composition from each other.

[0022] In the solar cell according to this embodiment, the photoelectric conversion layer may have a surface region containing the first compound and the second compound, for example, on the surface facing the second electrode. For example, in the solar cell 100 shown in FIG. 1, the first compound and the second compound may be present in a region on the surface 3a of the photoelectric conversion layer 3 facing the second electrode 4. Such a surface region 31 can also be considered an interface layer between the photoelectric conversion layer 3 and the layer adjacent thereto (the second electrode 4 in the solar cell of FIG. 1). In other words, the solar cell according to this embodiment may have an interface layer containing the first compound and the second compound between the surface of the photoelectric conversion layer facing the second electrode and the surface of the layer adjacent to the photoelectric conversion layer.

[0023] Between the layers constituting the solar cell 100, other layers may be further provided to suppress interfacial recombination between the layers and to bond the layers together.

[0024] For example, the solar cell according to this embodiment may further include a hole transport layer, which is disposed, for example, between the first electrode and the photoelectric conversion layer.

[0025] For example, the solar cell according to this embodiment may further include an electron transport layer, which is disposed, for example, between the second electrode and the photoelectric conversion layer.

[0026] 2 shows a cross-sectional view of a solar cell 200 according to the first embodiment. The solar cell 200 is a modified example (second configuration example) of the solar cell according to this embodiment.

[0027] Solar cell 200 has a configuration in which a hole transport layer and an electron transport layer are added to solar cell 100. Specifically, solar cell 200 includes a substrate 1, a first electrode 2, a hole transport layer 6, a photoelectric conversion layer 3, an electron transport layer 5, and a second electrode 4, in this order.

[0028] According to the above configuration, in addition to the same effect as that of solar cell 100, that is, the effect of improving photoelectric conversion efficiency, solar cell 200 can also efficiently utilize holes and electrons, thereby further improving photoelectric conversion efficiency.

[0029] Each component of the solar cell of the present disclosure will be described in detail below.

[0030] (Substrate 1) The substrate 1 serves to support the layers of the solar cell. The substrate 1 can be made of a transparent material. Examples of such materials include a glass substrate and a plastic substrate. The plastic substrate can also be a plastic film.

[0031] If the first electrode 2 has sufficient strength, the layers can be held by the first electrode 2, and therefore the substrate 1 does not need to be provided.

[0032] (1st electrode 2) The first electrode 2 is conductive. The first electrode 2 is, for example, translucent. The first electrode 2 transmits, for example, light from the visible region to the near-infrared region. The first electrode 2 may be made of, for example, a transparent and conductive metal oxide. Examples of such metal oxides include: (i) indium-tin composite oxide, (ii) antimony-doped tin oxide; (iii) fluorine-doped tin oxide; (iv) zinc oxide doped with at least one of boron, aluminum, gallium, and indium; or (v) any combination thereof; is.

[0033] The first electrode 2 may be formed using a non-transparent material and provided with a light-transmitting pattern. Examples of light-transmitting patterns include linear (e.g., striped), wavy, lattice (e.g., mesh), and punched metal patterns with numerous fine through-holes arranged regularly or irregularly. When the first electrode 2 has such a pattern, light can transmit through areas where no electrode material is present. Examples of non-transparent materials include platinum, gold, silver, copper, aluminum, rhodium, indium, titanium, iron, nickel, tin, zinc, or alloys containing any of these. A conductive carbon material may also be used as the non-transparent material.

[0034] When the solar cell does not include a hole transport layer 6, the first electrode 2 has a blocking property for electrons from the photoelectric conversion layer 3. In this case, the first electrode 2 does not make ohmic contact with the photoelectric conversion layer 3. Furthermore, the blocking property for electrons from the photoelectric conversion layer 3 refers to a property that allows only holes generated in the photoelectric conversion layer 3 to pass through, but does not allow electrons to pass through. The Fermi energy of a material having such a property is lower than the energy level of the bottom of the conduction band of the photoelectric conversion layer 3. The Fermi energy level of a material having such a property may be lower than the Fermi energy of the photoelectric conversion layer 3. Examples of materials that have a blocking property for electrons include platinum, gold, and carbon materials such as graphene.

[0035] When the solar cell includes a hole transport layer 6 between the first electrode 2 and the photoelectric conversion layer 3, the first electrode 2 does not need to have the ability to block electrons from the photoelectric conversion layer 3. In this case, the first electrode 2 may be made of a material that can form an ohmic contact with the photoelectric conversion layer 3. In this case, the first electrode 2 may or may not form an ohmic contact with the photoelectric conversion layer 3.

[0036] The light transmittance of the first electrode 2 may be, for example, 50% or more, or 80% or more. The wavelength of light that the first electrode 2 should transmit depends on the absorption wavelength of the photoelectric conversion layer 3.

[0037] The first electrode 2 may have a thickness of, for example, 1 nm or more and 1000 nm or less.

[0038] When the first electrode 2 is provided at a position farthest from the light incident side, the first electrode 2 does not necessarily have to be light-transmitting, and a non-transparent electrode material can also be used without processing.

[0039] (2nd electrode 4) The second electrode 4 is a layer having the same function as the first electrode 2, and can be made of the same material and structure as the first electrode 2. When the second electrode 4 is provided at the position farthest from the light incident side, the second electrode 4 does not need to be light-transmitting, and a non-transparent electrode material can be used without processing.

[0040] When the solar cell does not include the electron transport layer 5, the second electrode 4 has a blocking property against holes from the photoelectric conversion layer 3. In this case, the second electrode 4 does not make ohmic contact with the photoelectric conversion layer 3. Furthermore, the blocking property against holes from the photoelectric conversion layer 3 means that only electrons generated in the photoelectric conversion layer 3 pass through, while holes are not passed through. The Fermi energy of a material having such a property is higher than the energy level of the top of the valence band of the photoelectric conversion layer 3. The Fermi energy level of a material having such a property may be higher than the Fermi energy of the photoelectric conversion layer 3. A specific example of such a material is aluminum. Aluminum does not have optical transparency. Therefore, when forming a transparent electrode using aluminum, for example, an electrode having a pattern shape as described for the first electrode 2 is used.

[0041] (Photoelectric conversion layer 3) As described above, the photoelectric conversion layer 3 contains a mixed perovskite compound. The mixed perovskite compound can be represented by the composition formula ABX3.

[0042] where A is a monovalent cation. Examples of monovalent cations are alkali metal cations or organic cations. X is a monovalent anion. Examples of monovalent anions are halogen anions.

[0043] Each of the A and X sites may be occupied by multiple types of ions.

[0044] B is two or more kinds of divalent cations. Examples of divalent cations are divalent cations of transition metal elements and elements of groups 13 to 15. That is, B includes, for example, cations of a first metal element and a second metal element. The first metal element and the second metal element are, for example, transition metal elements or elements selected from elements of groups 13 to 15. The first metal element is, for example, lead. The second metal element is, for example, tin.

[0045] The photoelectric conversion layer 3 includes a first compound including a first metal element and a first amine material having two or more carbon atoms, and a second compound including a second metal element and a second amine material having two or more carbon atoms.

[0046] The first compound is not particularly limited as long as it contains a first metal element and a first amine material. For example, the first compound may have a structure in which the organic cation of the perovskite compound constituting the photoelectric conversion layer 3 is replaced with a first amine material, and further, the divalent cation may be composed only of cations of the first metal element. The second compound is not particularly limited as long as it contains a second metal element and a second amine material. For example, the second compound may have a structure in which the organic cation of the perovskite compound constituting the photoelectric conversion layer 3 is replaced with a second amine material, and further, the divalent cation may be composed only of cations of the second metal element.

[0047] The first and second amine materials are not particularly limited as long as they have two or more carbon atoms and contain a primary amino group, a secondary amino group, or a tertiary amino group. Examples of first and second amine materials having two or more carbon atoms include amine compounds in which an ethyl group, a long-chain alkyl group, a phenyl group, a benzyl group, or a phenethyl group is bonded to a nitrogen atom. Examples of such amine compounds include n-butylamine, phenethylamine, and ethylenediamine. The first and second amine materials may be at least one selected from the group consisting of n-butylamine, phenethylamine, and ethylenediamine.

[0048] The thickness of the photoelectric conversion layer 3 may be 100 nm or more and 2000 nm or less, depending on the level of light absorption.

[0049] The photoelectric conversion layer 3 can be formed by using a solution containing raw materials, by a coating method, a co-evaporation method, or the like.

[0050] The photoelectric conversion layer 3 may be in a form in which it is mixed with a part of the hole transport layer 6 and the electron transport layer 5 described later, or in a form in which it has a multi-area interface within the film.

[0051] As described above, the photoelectric conversion layer 3 may have a surface region 31 containing the first compound and the second compound, for example, on the surface facing the second electrode 4. That is, the first compound and the second compound may be present in a region on the surface 3a of the photoelectric conversion layer 3 facing the second electrode 4. The surface region 31 may be, for example, 1 nm to 10 nm deep from the surface 3a. The photoelectric conversion layer 3 having such a configuration can be formed by, for example, a coating method or a printing method. Examples of coating methods include doctor blade coating, bar coating, spray coating, dip coating, and spin coating. An example of a printing method is screen printing. For example, a photoelectric conversion layer 3 having the above-described surface region 31 can be formed by forming a precursor of the photoelectric conversion layer containing a perovskite compound containing a first metal element and a second metal element, and then applying a solution containing an amine material to the surface of the precursor of the photoelectric conversion layer using a known method to modify the surface.

[0052] (electron transport layer 5) The electron transport layer 5 includes a semiconductor. The electron transport layer 7 is preferably formed from a semiconductor having a band gap of 3.0 eV or more. This allows visible light and infrared light to transmit to the photoelectric conversion layer 3. Examples of the semiconductor include an organic n-type semiconductor or an inorganic n-type semiconductor.

[0053] Examples of organic n-type semiconductors include imide compounds, quinone compounds, fullerenes, and fullerene derivatives. Examples of inorganic n-type semiconductors include metal oxides and perovskite oxides. Examples of metal oxides include oxides of Cd, Zn, In, Pb, Mo, W, Sb, Bi, Cu, Hg, Ti, Ag, Mn, Fe, V, Zr, Sr, Ga, Si, or Cr. Examples of metal oxides include TiO2 or SnO2. Examples of perovskite oxides include SrTiO3 or CaTiO3.

[0054] The electron transport layer 7 may contain a material having a band gap larger than 6 eV. Examples of materials having a band gap larger than 6 eV include: (i) alkali metal or alkaline earth metal halides such as lithium fluoride and calcium fluoride; (ii) an oxide of an alkaline earth metal, such as magnesium oxide, or (iii) silicon dioxide, In this case, the electron transport layer 7 may have a thickness of, for example, 10 nm or less in order to ensure electron transport properties.

[0055] The electron transport layer 5 may include multiple layers made of different materials.

[0056] (Hole transport layer 6) The hole transport layer 6 contains a hole transport material. The hole transport material is a material that transports holes.

[0057] The hole transport material is, for example, an organic or inorganic semiconductor.

[0058] Examples of organic semiconductors include phenylamine, triphenylamine derivatives containing a tertiary amine in the skeleton, and PEDOT:PSS. The molecular weight of the organic material is not particularly limited, but it may be a polymer.

[0059] Examples of inorganic semiconductors are p-type semiconductors. Examples of p-type semiconductors are CuO, Cu2O, CuSCN, or NiO.

[0060] The thickness of the hole transport layer 6 may be 1 nm or more and 1000 nm or less, or 10 nm or more and 50 nm or less. Within this range, sufficient hole transport properties can be exhibited. Low resistance can be maintained, allowing for highly efficient photovoltaic power generation.

[0061] Examples of methods for forming the hole transport layer 6 include a coating method or a printing method. Examples of coating methods include a doctor blade method, a bar coating method, a spray method, a dip coating method, and a spin coating method. An example of a printing method is a screen printing method.

[0062] The hole transport layer 6 may contain a supporting electrolyte and a solvent. The supporting electrolyte and the solvent have the effect of stabilizing holes in the hole transport layer 6.

[0063] Examples of the supporting electrolyte include ammonium salts or alkali metal salts. Examples of the ammonium salt include tetrabutylammonium perchlorate, tetraethylammonium hexafluorophosphate, imidazolium salts, and pyridinium salts. Examples of the alkali metal salt include lithium perchlorate and potassium boron tetrafluoride.

[0064] The solvent contained in the hole transport layer 6 may have high ionic conductivity. The solvent may be either an aqueous solvent or an organic solvent. To stabilize the solute, the solvent may be an organic solvent. Examples of organic solvents include heterocyclic compounds such as tert-butylpyridine, pyridine, and n-methylpyrrolidone.

[0065] Ionic liquids may be used as solvents either alone or in combination with other solvents. Ionic liquids have low volatility and high flame retardancy.

[0066] Examples of ionic liquids are imidazolium compounds such as 1-ethyl-3-methylimidazolium tetracyanoborate, pyridine compounds, alicyclic amine compounds, aliphatic amine compounds, or azonium amine compounds.

[0067] (An example of a solar cell manufacturing method) The solar cell according to this embodiment may be manufactured by, for example, the following manufacturing method.

[0068] The manufacturing method according to this embodiment includes, for example, (A) forming a precursor of a photoelectric conversion layer containing a perovskite compound containing a first metal element and a second metal element; (B) applying a solution containing an amine material having two or more carbon atoms onto the precursor of the photoelectric conversion layer to form a compound containing the first metal element or the second metal element and the amine material, thereby forming a photoelectric conversion layer; Includes:

[0069] Here, an example of a method for fabricating the solar cell 200 of the second configuration example according to this embodiment will be described.

[0070] The solar cell 300 is obtained by forming a first electrode 2, a hole transport layer 6, a photoelectric conversion layer 3, an intermediate layer 7, an electron transport layer 5, and a second electrode 4 on a substrate 1 by a coating method such as spin coating, spray coating, die coating, inkjet, gravure coating, or flexo coating, a physical vapor deposition (PVD) method such as evaporation or sputtering, or a chemical vapor deposition (CVD) method using heat, light, plasma, or the like. The photoelectric conversion layer 3 can be produced, for example, by a method including the above-mentioned (A) and (B). [Example]

[0071] The present invention will now be described in more detail with reference to examples.

[0072] Example 1 A method for producing the solar cell according to Example 1 will be described below.

[0073] First, a glass substrate having a thickness of 0.7 mm was prepared.

[0074] A tin-doped indium oxide layer having a thickness of 150 nm was formed on the substrate by sputtering, thus forming a first electrode.

[0075] Next, a PEDOT:PSS dispersion (manufactured by Heraeus) was applied onto the first electrode by spin coating, thus forming a hole transport layer.

[0076] Next, a raw material solution for forming a photoelectric conversion layer was applied onto the hole transport layer using a spin coating method. The raw material solution was a mixture of PbI2 (0.58 mol / L, manufactured by Tokyo Chemical Industry Co., Ltd.), SnI2 (0.87 mol / L, manufactured by Sigma-Aldrich Co., Ltd.), SnF2 (0.087 mol / L, manufactured by Sigma-Aldrich Co., Ltd.), formamidinium iodide (0.58 mol / L, manufactured by GreatCell Solar Co., Ltd.) (hereinafter referred to as "FAI"), methylammonium iodide (0.87 mol / L, manufactured by GreatCell Solar Co., Ltd.) (hereinafter referred to as "MAI"), dimethyl sulfoxide (DMSO, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), and N,N-dimethylformamide (DMF, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.). The mixing ratio of DMSO and DMF in the raw material solution was 1:4 by volume. This produced a precursor for the photoelectric conversion layer.

[0077] Next, a solution containing an amine material having two or more carbon atoms was applied to the precursor of the photoelectric conversion layer. In this way, a first compound of a first metal element and the amine material and a second compound of a second metal element and the amine material were formed inside the photoelectric conversion layer. The solution containing the amine material was a mixture of ethylenediamine (0.1 mmol / L, manufactured by Sigma-Aldrich) and toluene (manufactured by Fujifilm Wako Pure Chemical Industries).

[0078] Next, a 25 nm thick fullerene film and a 5 nm thick bathocuproine (BCP) film were successively formed on the photoelectric conversion layer by vapor deposition, forming an electron transport layer.

[0079] Next, a silver film having a thickness of 100 nm was formed on the electron transport layer by evaporation, thus forming a second electrode.

[0080] In this way, the solar cell according to Example 1 was obtained.

[0081] Example 2 In Example 2, the solution containing an amine material having two or more carbon atoms was a mixture of phenethylammonium iodide (0.1 g / L, manufactured by Tokyo Chemical Industry Co., Ltd.) and 2-propanol (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.). Except for this, the solar cell according to Example 2 was obtained in the same manner as in Example 1.

[0082] (Comparative Example 1) In Comparative Example 1, the step of applying a solution containing an amine material having two or more carbon atoms to the photoelectric conversion layer was not performed. Other than this, the solar cell according to Comparative Example 1 was obtained in the same manner as in Example 1.

[0083] (Evaluation of solar cell characteristics) The conversion efficiencies of the top solar cell of Example 1, Example 2, and Comparative Example 1 were measured. A solar simulator (manufactured by Bunkoukeiki Co., Ltd.) and an electrochemical analyzer ALS (manufactured by BAS Inc.) were used to measure the conversion efficiencies. The solar simulator simulated sunlight (illuminance 100 mW / cm) to have a spectrum similar to that of sunlight. 2 ) was irradiated onto the cell. The current-voltage characteristics (hereinafter referred to as IV characteristics) of the solar cell were measured by measuring the output current value while changing the applied voltage using an electrochemical analyzer for the cell irradiated with the simulated sunlight. The conversion efficiency was calculated from the open-circuit voltage, short-circuit current, and fill factor of the obtained IV characteristics.

[0084] Fig. 3 is a graph showing the IV characteristics of the solar cells according to Example 1 and Comparative Example 1. The horizontal axis of Fig. 3 represents the applied voltage, and the vertical axis represents the current density.

[0085] As shown in Figure 3, it was confirmed that the solar cell according to Example 1 had a higher open circuit voltage than the solar cell according to Comparative Example 1. At this time, the conversion efficiencies of the solar cells according to Example 1 and Comparative Example 1 were 19.74% and 16.49%, respectively. Therefore, it was confirmed that the configuration of the solar cell according to Example 1 improved the conversion efficiency.

[0086] Next, four solar cells were fabricated for each of Example 1, Example 2, and Comparative Example 1, and the open circuit voltage was measured when irradiated with simulated sunlight.

[0087] FIG. 4 is a graph plotting the open circuit voltages of the solar cells according to Example 1, Example 2, and Comparative Example 1.

[0088] As shown in FIG. 4, it was confirmed that the solar cells according to Examples 1 and 2 had a higher open-circuit voltage than the solar cell according to Comparative Example 1.

[0089] Next, X-ray diffraction was measured for the photoelectric conversion layers constituting the solar cells according to Example 1 and Comparative Example 1. A fully automated multipurpose X-ray diffractometer, SmartLab (manufactured by Rigaku), was used for the X-ray diffraction measurement. X-rays were irradiated onto the photoelectric conversion layer while varying the incident angle and exit angle in the range of 10 to 16 degrees, and the diffraction intensity was measured.

[0090] Fig. 5 is a graph showing X-ray diffraction patterns of the photoelectric conversion layers constituting the solar cells according to Example 1 and Comparative Example 1. The horizontal axis of Fig. 5 represents the incident angle and outgoing angle of the X-ray, and the vertical axis represents the diffraction intensity.

[0091] 5, a peak was observed at 14.1 degrees in Example 1 and Comparative Example 1. Furthermore, in Example 1, two peaks were observed at low angles of 11.2 degrees and 12.2 degrees.

[0092] 5 shows the X-ray diffraction intensity of a compound obtained by applying a solution containing the amine material of Example 1 to a perovskite compound containing only tin at the B site. Data shown as diffraction B shows the X-ray diffraction intensity of a compound obtained by applying a solution containing the amine material of Example 1 to a perovskite material containing only lead at the B site.

[0093] In FIG. 5, when Example 1 is compared with diffraction A and diffraction B, it was confirmed that the peak at 12.2 degrees coincides with diffraction A, and the peak at 11.2 degrees coincides with diffraction B.

[0094] Therefore, it was confirmed that the photoelectric conversion layer constituting the solar cell according to Example 1 contains both a compound containing tin and an amine material that exhibits diffraction A, and a compound containing lead and an amine material that exhibits diffraction B, in addition to the perovskite material in which tin and lead are mixed at the B site shown in Comparative Example 1. [Industrial Applicability]

[0095] The solar cells of the present disclosure can be used in a variety of applications, including traditional solar cell applications. [Explanation of symbols]

[0096] 1 board 2 1st electrode 3 Photoelectric conversion layer 31 Surface area 4 Second electrode 5 Electron transport layer 6. Middle class 7. Hole transport layer

Claims

1. a first electrode, a photoelectric conversion layer, and a second electrode in this order; The photoelectric conversion layer is a perovskite compound containing a first metal element and a second metal element; a first compound comprising the first metallic element and a primary amine material having two or more carbon atoms; a second compound comprising the second metallic element and a second amine material having two or more carbon atoms; Including, solar cells.

2. the photoelectric conversion layer has a surface region including the first compound and the second compound on a surface facing the second electrode; The solar cell according to claim 1 .

3. further comprising an electron transport layer; the electron transport layer is provided between the photoelectric conversion layer and the second electrode; The solar cell according to claim 1 or 2.

4. the first metal element is lead, the second metal element is tin; The solar cell according to claim 1 .

5. the amine material is at least one selected from the group consisting of n-butylamine, phenethylamine, and ethylenediamine; The solar cell according to claim 1 .

6. (A) forming a precursor of a photoelectric conversion layer including a perovskite compound including a first metal element and a second metal element; (B) applying a solution containing an amine material having two or more carbon atoms onto the precursor of the photoelectric conversion layer to form a compound containing the first metal element or the second metal element and the amine material, thereby forming a photoelectric conversion layer; A method for manufacturing a solar cell, comprising:

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