Producing method of halogenated tin perovskite using alcohol solvent

Abstract

To produce organic and inorganic hybrid or inorganic halogenated tin perovskite with a solvent lower in environmental load than DMF and DMSO.SOLUTION: A method for producing halogenated tin perovskite comprises a step A of forming a precursor layer on a substrate by applying one of an alcohol solution of tin halide and an alcohol solution of halogenated organic amine or halogenated alkali metal salt onto a substrate, and a step B of forming a halogenated tin perovskite layer on a substrate by applying the other of the alcohol solution of tin halide and the alcohol solution of halogenated organic amine or halogenated alkali metal salt onto the precursor layer.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present application relates to a method for producing tin halide perovskite containing tin halide and having a perovskite structure using an alcohol as a solvent. [Background technology]

[0002] Solar cells using organic / inorganic perovskites such as CH3NH3PbI3 or CH3NH3SnI3 as a light-absorbing layer exhibit high energy conversion efficiencies approaching those of currently widely available silicon solar cells. Conventionally, organic / inorganic perovskites have been fabricated using the following method: First, lead halide or tin halide is dissolved in N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO), applied to a substrate, and dried. Next, a solution of methylammonium halide (CH3NH3X) or formamidinium halide ((NH2)2CHX) dissolved in 2-propanol is applied to the substrate and dried (Non-Patent Document 1). [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] Adv. Mater. 2018, 30, 1703800. Summary of the Invention [Problem to be solved by the invention]

[0004] The DMF and DMSO used in the film-forming method for organic-inorganic perovskite described in Non-Patent Document 1 have safety concerns for the human body and the environment. The present application has been made in light of these circumstances, and aims to produce organic-inorganic hybrid or inorganic tin halide perovskite using a solvent that has a smaller environmental impact than DMF and DMSO. [Means for solving the problem]

[0005] The method for producing tin halide perovskite of the present application includes step A of applying one of an alcohol solution of tin halide and an alcohol solution of a halogenated organic amine or an alcohol solution of an alkali metal halide onto a substrate to form a precursor layer on the substrate, and step B of applying the other of the alcohol solution of tin halide and an alcohol solution of a halogenated organic amine or an alcohol solution of an alkali metal halide onto the precursor layer to form a tin halide perovskite layer on the substrate. [Effects of the Invention]

[0006] According to the method for producing tin halide perovskite of the present invention, organic-inorganic hybrid or inorganic tin halide perovskite can be produced using a solvent that has a smaller environmental impact than DMF and DMSO. [Brief explanation of the drawings]

[0007] [Figure 1] 1 shows the absorption spectrum of a tin bromide perovskite layer obtained in an example. [Figure 2] 1 shows an X-ray diffraction pattern of a tin bromide perovskite layer obtained in an example. DETAILED DESCRIPTION OF THE INVENTION

[0008] The method for producing tin halide perovskite according to the first embodiment of the present application includes steps A and B. The tin halide perovskite contains tin halide and has a perovskite structure. The tin halide perovskite may be an organic / inorganic perovskite or an inorganic perovskite. In step A, a precursor layer is formed on a substrate by applying an alcohol solution of tin halide or an alcohol solution of an organic amine halide or an alkali metal halide salt.

[0009] "An alcohol solution of a tin halide and either an alcohol solution of an organic halide amine or an alkali metal halide salt" means either (1) an alcohol solution of a tin halide, or (2) an alcohol solution of an organic halide amine or an alcohol solution of an alkali metal halide. Examples of tin halides include tin chloride, tin bromide, and tin iodide.

[0010] An alcohol solution of tin halide is a liquid containing alcohol, which is the solvent with the largest mass proportion of the total solvent, i.e., alcohol, which is the main component of the solvent, and tin halide dissolved in this alcohol. The alcohol solution of tin halide may contain solvents other than alcohol, or may be composed solely of alcohol. The solvent that makes up the alcohol solution preferably has a higher mass proportion of alcohol, because tin halide dissolves easily in alcohol. The mass proportion of alcohol in the solvent is preferably 80% or more, more preferably 90% or more, and even more preferably 95% or more. Furthermore, the alcohol is preferably ethanol, propanol, or butanol, because this has relatively little impact on the human body and the environment. The alcohol solution of tin halide may contain multiple types of alcohol.

[0011] The halogen element of the halogenated organic amine is preferably bromine or iodine. This is because perovskite is easily obtained by reaction with tin halide. There are no particular limitations on the halogenated organic amine as long as it is soluble in alcohol. Examples of halogenated organic amines include benzylammonium halide, butylammonium halide, ethylammonium halide, methylammonium halide, diethylammonium halide, dimethylammonium halide, ethanediammonium halide, formamidinium halide, propylammonium halide, guanidinium halide, and phenethylammonium halide. Of these, the halogenated organic amine is preferably methylammonium halide or formamidinium halide. This is because perovskite is easily obtained by reaction with tin halide.

[0012] An alcohol solution of a halogenated organic amine is a liquid containing alcohol, which is the solvent with the largest mass ratio among all solvents, i.e., alcohol, which is the main component of the solvent, and a halogenated organic amine dissolved in this alcohol. The alcohol solution of a halogenated organic amine may contain a solvent other than alcohol, or may be composed solely of alcohol. It is preferable that the solvent constituting the alcohol solution has a high mass ratio of alcohol, because this is because the halogenated organic amine is easily soluble in the alcohol.

[0013] The mass ratio of the alcohol in the solvent is preferably 80% or more, more preferably 90% or more, and even more preferably 95% or more. Furthermore, the alcohol is preferably ethanol, propanol, or butanol, as these have relatively little impact on the human body and the environment. The alcohol solution of the halogenated organic amine may contain multiple types of alcohol.

[0014] An alkali metal halide salt is a salt composed of an alkali metal and a halogen element. Examples of alkali metal halide salts include lithium halide, sodium halide, potassium halide, rubidium halide, and cesium halide. The halogen element of the alkali metal halide salt is preferably bromine or iodine, because this is because it reacts with tin halide to easily produce perovskite.

[0015] The alcohol solution of an alkali metal halide salt is a liquid containing alcohol, which is the solvent with the largest mass ratio among all solvents, i.e., alcohol, which is the main component of the solvent, and an alkali metal halide salt dissolved in this alcohol. The alcohol solution of an alkali metal halide salt may contain a solvent other than alcohol, or may be composed solely of alcohol as the solvent.

[0016] However, it is preferable that the solvent constituting the alcohol solution has a high mass ratio of alcohol, since alkali metal halides are easily soluble in it. The mass ratio of alcohol in the solvent is preferably 80% or more, more preferably 90% or more, and even more preferably 95% or more. Furthermore, the alcohol is preferably ethanol, propanol, or butanol, since these have relatively little impact on the human body and the environment. The alcohol solution of alkali metal halide may contain multiple types of alcohol.

[0017] The substrate can be appropriately selected depending on the purpose of forming a tin halide perovskite layer thereon. For example, when the tin halide perovskite layer is used as a light absorbing layer of a solar cell, the substrate is an electron transport layer or an electrode. According to the first embodiment of the method for producing a tin halide perovskite using alcohol, a tin halide perovskite layer can be easily formed on substrates that are damaged by DMF and DMSO, such as an ITO layer, a SnO layer, a perovskite layer, a fullerene derivative layer, a 2,2',7,7'-tetrakis[N,N-di-p-methoxyphenylamino]-9,9'-spirobifluorene (sprio-OMeTAD) layer, and an organic semiconductor layer that constitute a solar cell.

[0018] In the process of applying a predetermined alcohol solution to a substrate to form a precursor layer on the substrate, for example, the substrate is spin-coated with the predetermined alcohol solution and then dried to evaporate the alcohol, thereby forming a precursor layer. The precursor layer is a tin halide layer when the predetermined alcohol solution is an alcohol solution of a tin halide, an organic halide amine layer when the predetermined alcohol solution is an alcohol solution of an organic halide, or an alkali metal halide layer when the predetermined alcohol solution is an alcohol solution of an alkali metal halide.

[0019] In step B, the other of the alcohol solution of tin halide and the alcohol solution of a halogenated organic amine or an alkali metal halide salt is applied to the precursor layer obtained in step A to form a tin halide perovskite layer on the substrate. "The other of the alcohol solution of tin halide and the alcohol solution of a halogenated organic amine or an alkali metal halide salt" means the one not selected in step A out of (1) the alcohol solution of tin halide and (2) the alcohol solution of a halogenated organic amine or an alcohol solution of an alkali metal halide. In other words, if (1) is used in step A, then (2) is used in step B, and if (2) is used in step A, then (1) is used in step B.

[0020] The alcohol solution of tin halide, alcohol solution of halogenated organic amine, and alcohol solution of alkali metal halide salt in step B are the same as those in step A. Different alcohols may be used in steps A and B. In the process of applying a predetermined alcohol solution onto the precursor layer to form a tin halide perovskite layer on the substrate, for example, the predetermined alcohol solution is spin-coated onto the precursor layer and then dried to evaporate the alcohol, thereby forming a tin halide perovskite layer on the substrate.

[0021] In step B, the precursor layer is brought into contact with a predetermined alcohol solution, whereby components in the alcohol solution are incorporated into the precursor layer, perovskite crystals are formed, and a tin halide perovskite layer is obtained. The formation of this tin halide perovskite layer is represented by the following chemical reaction formula. That is, when the precursor layer is a tin halide layer and the predetermined alcohol solution is an alcohol solution of a halogenated organic amine, or when the precursor layer is a halogenated organic amine layer and the predetermined alcohol solution is an alcohol solution of a tin halide, SnX 1 2+RX 2 →RSnX 1 3-x X 2 x (0≦x≦3) where X 1 and X 2 is a halogen atom. X 1 and X 2 may be the same or different. R is an organic amine group, i.e., a hydrocarbon group in which one or more hydrogen atoms have been replaced with an amino group.

[0022] Furthermore, when the precursor layer is a tin halide layer and the predetermined alcohol solution is an alcohol solution of an alkali metal halide, or when the precursor layer is an alkali metal halide layer and the predetermined alcohol solution is an alcohol solution of a tin halide, SnX 1 2+MX 2 →MSnX 1 3-xX 2 x (0≦x≦3) where X 1 and X 2 is a halogen atom. X 1 and X 2 may be the same or different. M is an alkali metal.

[0023] In the method for producing tin halide perovskite of the present application, the two components that make up the tin halide perovskite are each dissolved in alcohol, and the two alcohol solutions are applied sequentially to a substrate. Because both components are in the form of alcohol solutions, the order in which the two components are applied is not limited. Therefore, the order in which the two components are applied can be selected depending on the properties of the base on which the tin halide perovskite film is to be formed.

[0024] In the method for producing tin halide perovskite of the present application, after step B, a new tin halide perovskite layer may be further formed on the tin halide perovskite layer. Tin halide perovskite is damaged by DMF or DMSO. For this reason, it is difficult to form a new tin halide perovskite layer on the tin halide perovskite layer in a method for forming tin halide perovskite using a solution mainly containing DMF or DMSO. However, the method for producing tin halide perovskite of the present application uses a solution mainly containing alcohol, so a new tin halide perovskite layer can be formed on the tin halide perovskite layer.

[0025] That is, the method for producing tin halide perovskite according to the second embodiment of the present application further includes steps C and D after step B of the method for producing tin halide perovskite according to the first embodiment. In step C, an alcohol solution of tin halide and one of an alcohol solution of a halogenated organic amine or an alcohol solution of an alkali metal halide are applied to the tin halide perovskite layer formed in step B to form a new precursor layer on the tin halide perovskite layer. Step C is the same as step A, except that the object to which the "alcohol solution of tin halide and one of an alcohol solution of a halogenated organic amine or an alcohol solution of an alkali metal halide" is applied is different.

[0026] In step D, the other of the alcohol solution of tin halide and the alcohol solution of a halogenated organic amine or an alkali metal halide salt is applied onto the new precursor layer formed in step C to form a new tin halide perovskite layer on the tin halide perovskite layer formed in step B. Step D is the same as step B except that the object onto which the "alcohol solution of tin halide and the other of the alcohol solution of a halogenated organic amine or an alkali metal halide salt" is applied is different.

[0027] In step C, an alcohol solution containing the same tin halide perovskite raw material components as in step B may be used instead of an alcohol solution containing the same tin halide perovskite raw material components as in step A. In step D, an alcohol solution containing the same tin halide perovskite raw material components as in step C may be used instead of an alcohol solution containing the same tin halide perovskite raw material components as in step B. Furthermore, the solvents of the alcohol solutions used in steps A, B, C, and D may be partly or entirely the same, or may all be different.

[0028] Furthermore, the tin halide perovskite layer formed in steps A and B and the new tin halide perovskite layer formed in steps C and D may be the same or different. However, when stacking tin halide perovskite layers to use as a light absorbing layer in a solar cell, it is preferable that the tin halide perovskite layer and the new tin halide perovskite layer are the same. This is because this improves the bonding of the electron bands between the two stacked halide perovskite layers. [Example]

[0029] A 0.2 M solution of SnBr2 (Tokyo Chemical Industry Co., Ltd., T3573) in 2-propanol was prepared. An indium tin oxide (ITO) substrate (Geomatec Co., Ltd., 1001) was spin-coated with tin oxide colloid (Alfa Aesar, 44592) and dried to prepare an electron transport layer substrate (SnO2 / ITO substrate). The SnO2 / ITO substrate was spin-coated with the above-mentioned 2-propanol solution of SnBr2 and dried to form a precursor layer, the SnBr2 layer. A 0.4 M solution of CH3NH3I (Tokyo Chemical Industry Co., Ltd., M2556) in 2-propanol was also prepared. The CH3NH3I 2-propanol solution was spin-coated on the SnBr2 layer and dried to form a tin bromide perovskite layer on the SnO2 / ITO substrate. The formation of this tin bromide perovskite layer is represented by the following chemical reaction equation: SnBr2+CH3NH3I→CH3NH3SnBr 3-x I x (0≦x≦3)

[0030] Additionally, three types of tin bromide perovskite layers were formed on three SnO2 / ITO substrates using three different 2-propanol solutions of SnBr2 (0.4M, 0.6M, and 0.8M) and a 0.4M 2-propanol solution of CH3NH3I, using the same method as above. The four types of tin bromide perovskite layers obtained exhibited a dark brown color. The absorption spectra of these four types of tin bromide perovskite layers were measured. The results are shown in Figure 1. As shown in Figure 1, all four types of tin bromide perovskite layers exhibited optical absorption in the visible range.

[0031] X-ray diffraction was also measured on a tin bromide perovskite layer formed using a 0.4M SnBr2 solution in 2-propanol. The results are shown in Figure 2. As shown in Figure 2, diffraction peaks at 2θ = ~14.5°, ~24°, ~29°, and ~33° were observed, which were attributable to the diffraction of the (100), (111), (200), and (210) planes of the perovskite crystal. 3-x I x The production of (0≦x≦3) was shown. [Industrial Applicability]

[0032] The tin halide perovskite produced by the method for producing tin halide perovskite of the present invention can be used in solar cells, optical functional materials, and the like.

Claims

1. a step A in which one of (1) an alcohol solution of a tin halide and (2) an alcohol solution of a halogenated organic amine or an alkali metal halide is applied to a substrate to form a precursor layer on the substrate; a step B of applying one of (1) and (2) in the step A, whichever was not selected in the step A, onto the precursor layer to form a tin halide perovskite layer on the substrate; a step C of applying one of (1) an alcohol solution of a tin halide or (2) an alcohol solution of a halogenated organic amine or an alkali metal halide salt onto the tin halide perovskite layer to form a new precursor layer on the tin halide perovskite layer; a step D of applying one of (1) and (2) in the step C, whichever was not selected in the step C, onto the new precursor layer to form a new tin halide perovskite layer on the tin halide perovskite layer; A method for producing a tin halide perovskite having the formula:

2. In claim 1, In the step A, an alcohol solution of a halogenated organic amine is applied, The method for producing tin halide perovskite, wherein the halogenated organic amine is a methylammonium halide or a formamidinium halide.

3. a step A in which one of (1) an alcohol solution of a tin halide and (2) an alcohol solution of a halogenated organic amine or an alkali metal halide is applied to a substrate to form a precursor layer on the substrate; a step B of applying one of the steps (1) and (2), whichever was not selected in the step A, onto the precursor layer to form a tin halide perovskite layer on the substrate; and In the step B, an alcohol solution of a halogenated organic amine is applied, The method for producing tin halide perovskite, wherein the halogenated organic amine is a methylammonium halide or a formamidinium halide.

4. In any one of claims 1 to 3, The method for producing tin halide perovskite, wherein the alcohol solution is an ethanol solution, a propanol solution, or a butanol solution.

5. a step A in which one of (1) an alcohol solution of a tin halide and (2) an alcohol solution of a halogenated organic amine or an alkali metal halide is applied to a substrate to form a precursor layer on the substrate; a step B of applying one of the steps (1) and (2), whichever was not selected in the step A, onto the precursor layer to form a tin halide perovskite layer on the substrate; and The method for producing tin halide perovskite, wherein the substrate is an ITO layer, a SnO2 layer, a perovskite layer, a fullerene derivative layer, a 2,2',7,7'-tetrakis[N,N-di-p-methoxyphenylamino]-9,9'-spirobifluorene layer, or an organic semiconductor layer.

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