WO2023058983A1

WO2023058983A1 - Method and device for preparing perovskite thin film by using additives

Info

Publication number: WO2023058983A1
Application number: PCT/KR2022/014459
Authority: WO
Inventors: 전남중; 장경순; 김영웅; 김영윤; 김범수; 김승우; 김근진
Original assignee: 한국화학연구원
Priority date: 2021-10-06
Filing date: 2022-09-27
Publication date: 2023-04-13
Also published as: KR20230049506A

Abstract

A method for preparing a perovskite thin film by using additives, according to one embodiment of the present disclosure, comprise the steps of: supplying a perovskite precursor solution to a substrate; supplying a first additive to the substrate; supplying, to the substrate, a second additive that differs from the first additive; and annealing the substrate.

Description

Method and device for manufacturing perovskite thin film using additives

The present disclosure relates to a method and apparatus for manufacturing a perovskite thin film using additives, and more particularly, to a method for manufacturing a perovskite thin film with reduced wrinkles and voids using additives and devices.

A perovskite solar cell refers to a solar cell based on a light absorber of a perovskite (ABX ₃ ) structure. The perovskite material has a high absorption rate for visible light, a wide light absorption range, can generate a high short-circuit current only by using a small amount of material, and at the same time has a high open-circuit voltage as a battery device. The solar cell has a high light absorption coefficient, so it can effectively absorb sunlight even with a sub-micrometer thickness, and thus has excellent photoelectric conversion efficiency, such as a power conversion efficiency (PCE) exceeding 20%. Since the perovskite thin film used in the thin solar cell is thin, it has the advantage of low material cost.

A conventional method for producing a large-area perovskite thin film is coated by dissolving a perovskite precursor in a solvent. When using this method, since the supersaturated precursors crystallize into a perovskite material due to evaporation of the solvent and form a solid perovskite thin film, wrinkles are generated on the surface of the perovskite thin film, and the thin film There are also many voids or pinholes inside, making it difficult to manufacture a high-quality perovskite thin film.

As a method for controlling the surface of a perovskite thin film having a non-uniform shape due to rapid reaction and self-assembly between perovskite precursors, DMSO (Dimethylsulfoxide) is used or to remove moisture (H ₂ O) An inert gas (N ₂ ), rather than a general ambient air, was used. However, in order to manufacture a large-area perovskite thin film, it is necessary to lower the production cost, increase the uniformity of the perovskite thin film to increase reproducibility, and secure stable photoelectric conversion efficiency. Accordingly, it is required to develop a technology capable of forming a high-quality and large-area perovskite light absorption layer thin film more effectively.

An object of the present disclosure is to provide a perovskite thin film having high surface crystallization using an additive.

An object of the present disclosure is to provide a uniform large-area perovskite thin film using an additive.

An object of the present disclosure is to provide a large-area perovskite thin film with high reproducibility using additives.

An object of the present disclosure is to provide a perovskite thin film that can be manufactured in a large area in an atmospheric environment using additives.

An object of the present disclosure is to simultaneously improve wrinkles formed on the surface of a perovskite thin film and voids formed inside a perovskite thin film by using additives.

A method for manufacturing a perovskite thin film according to an embodiment of the present disclosure includes supplying a perovskite precursor solution onto a substrate, supplying a first additive onto a substrate, and a second additive different from the first additive. and supplying the substrate onto the substrate and annealing the substrate.

Supplying the perovskite precursor solution on the substrate according to an embodiment of the present disclosure includes supplying an anti-solvent on the substrate.

The first additive according to an embodiment of the present disclosure corresponds to an additive that suppresses generation of wrinkles on the surface of the perovskite thin film.

The second additive according to an embodiment of the present disclosure corresponds to an additive that suppresses generation of voids inside the perovskite thin film.

The first additive according to an embodiment of the present disclosure corresponds to formamide.

The second additive according to an embodiment of the present disclosure corresponds to MACl.

A method for manufacturing a perovskite thin film according to an embodiment of the present disclosure includes being made in an atmospheric environment.

The perovskite precursor according to an embodiment of the present disclosure includes Formamidinium (FA).

Perovskite thin film manufacturing apparatus according to an embodiment of the present disclosure is different from the solution supply unit for supplying the perovskite precursor solution to the substrate, the first additive supply unit for supplying the first additive to the substrate, the first additive It includes a second additive supplying unit supplying a second additive onto the substrate and an annealing unit annealing the substrate.

A solution containing a perovskite precursor according to an embodiment of the present disclosure includes a perovskite precursor, a solvent dissolving the perovskite precursor, a first additive, and a second additive different from the first additive.

According to an embodiment of the present disclosure, the first additive corresponds to formamide, and the second additive corresponds to MACl.

Using various embodiments of the present disclosure, it is possible to provide a perovskite thin film having high surface crystallization.

Using various embodiments of the present disclosure, it is possible to provide a high-density and uniform large-area perovskite thin film.

Using various embodiments of the present disclosure, it is possible to provide a large-area perovskite thin film with high reproducibility.

Using various embodiments of the present disclosure, a perovskite thin film may be formed in a large area in an ambient air.

Using various embodiments of the present disclosure, wrinkles formed on the surface of the perovskite thin film and voids formed inside the perovskite thin film can be simultaneously improved.

The technical effects of the present invention are not limited to those mentioned above, and other technical effects not mentioned will be clearly understood by those skilled in the art from the description below.

Embodiments of the present disclosure will be described with reference to the accompanying drawings described below.

1 and 2 are views showing differences in the quality of perovskite thin films manufactured according to the process environment.

3 is a view showing a process of forming wrinkles and voids of a perovskite thin film according to the prior art.

4 is a view showing a method for improving wrinkles of a perovskite thin film according to the prior art.

5 is a surface and side photographed image of a perovskite thin film according to the type of additive.

6 is a photographic image of the surface and bottom of a perovskite thin film according to the type of additive.

7 is a diagram illustrating a manufacturing process of a perovskite thin film using an additive according to an embodiment of the present disclosure.

8 to 12 are diagrams showing crystallinity, photoluminescence (PL) intensity, and the like of perovskite thin films.

13 to 16 show device J-V characteristics and photostability test results of perovskite thin films fabricated in an atmospheric environment.

17 to 21 show test results of large-area perovskite thin films and devices fabricated in an atmospheric environment.

22 is a surface image of a perovskite thin film according to additives.

23 is a side image of a perovskite thin film according to additives.

Hereinafter, specific details for the implementation of the present disclosure will be described in detail with reference to the accompanying drawings. However, in the following description, if there is a risk of unnecessarily obscuring the gist of the present disclosure, detailed descriptions of well-known functions or configurations will be omitted.

Throughout the present specification, when a certain component is said to "include", it means that it may further include other components without excluding other components unless otherwise stated.

The terms "about" and the like used throughout this specification are intended to encompass tolerances when tolerances exist.

Throughout the present specification, the term "at least one" included in the expression of the Markush form means including one or more selected from the group consisting of elements described in the expression of the Markush form.

Throughout this specification, reference to "A and/or B" means "A, or B, or A and B".

Throughout the present specification, “perovskite” or “PE” means a material having a perovskite crystal structure, and may have various perovskite crystal structures in addition to the crystal structure of ABX ₃ .

Throughout the present specification, when only efficiency is described without any additional explanation, the efficiency means power conversion efficiency (PCE).

Throughout the present specification, "precursor" may mean a precursor or reactant used to prepare perovskite, and is not limited to a specific material.

Throughout this specification, "solvent" is a substance for dissolving the perovskite precursor.

Throughout the present specification, "MF" or "Mixed" means that MACl (methylammonium chloride) and formamide are added.

The perovskite composition used in the images used herein corresponds to Cs _0.17 FA _0.83 Pb(I _0.8 Br _0.2 ) ₃ unless otherwise indicated.

1 and 2 are views showing differences in the quality of perovskite thin films manufactured according to the process environment. The solvent used in the process of manufacturing the perovskite thin film reduces the solubility of the perovskite precursor solution because it easily combines with moisture contained in a general atmospheric environment. As a result, wrinkles are formed on the surface of the perovskite thin film and voids are formed inside, resulting in an unbalanced thin film with low crystallinity. Thus, in order to form a uniform thin film with improved wrinkles and voids of the perovskite thin film, the perovskite thin film is prepared in an inert gas (eg, N ₂ ) environment from which moisture is removed. However, in the case of a process using nitrogen gas, since the cost is high, there is a limit to the fabrication and commercialization of large-area perovskite.

3 is a view showing a process of forming wrinkles and voids in a perovskite thin film according to the prior art. According to the conventional manufacturing process of the perovskite thin film, the surface portion during anti-solvent treatment due to materials with low solubility (eg, CsI and PbBr ₂ ) added to the perovskite precursor solution A difference in crystallization occurs, resulting in wrinkles on the surface.

Furthermore, the surface changes to the perovskite phase in a short time, but there is a residual solvent that has not evaporated inside, and voids are generated inside as this residual solvent evaporates during annealing.

4 is a view showing a method for improving wrinkles of a perovskite thin film according to the prior art. In the conventional perovskite thin film manufacturing process, wrinkles are formed on the surface of the perovskite thin film due to the low solubility of the perovskite precursor solution. Therefore, the composition of the solvent can be changed to suppress wrinkles by increasing the solubility of the perovskite precursor solution. For example, as the ratio of DMSO in a mixed solvent of DMF (dimethylformamide) and DMSO (dimethyl sulfoxide) increases, the effect of improving wrinkles becomes more pronounced. However, as shown in FIG. 3, more voids are formed inside the perovskite thin film, and the side effect of reducing the grain size of the thin film occurs.

5 is a surface and side photographed image of a perovskite thin film according to the type of additive. 6 is a photographic image of the surface and bottom of a perovskite thin film according to the type of additive.

According to an embodiment of the present disclosure, different additives are added to the perovskite precursor solution. For example, the first additive corresponds to formamide. Formamide serves to prevent perovskite surface wrinkles. For example, the second additive corresponds to methylammonium chloride (MACl). MACl improves voids formed inside the perovskite thin film.

In the figure, "Pristine" corresponds to an image taken of a perovskite thin film manufactured according to a general manufacturing process without additives.

"Formamide" corresponds to an image taken of a perovskite thin film prepared according to a manufacturing process in which formamide is added to a perovskite precursor solution. When only formamide was added, surface wrinkles were improved, but internal voids were still present.

"MACl" corresponds to an image taken of a perovskite thin film prepared according to a manufacturing process in which MACl is added to a perovskite precursor solution. When only MACl was added, surface wrinkles still existed, but internal voids were reduced.

"Mixed" corresponds to an image taken of a perovskite thin film prepared according to a manufacturing process in which formamide and MACl are added to a perovskite precursor solution. It can be seen that both surface wrinkles and internal voids are reduced.

7 is a diagram illustrating a manufacturing process of a perovskite thin film using an additive according to an embodiment of the present disclosure. A method for manufacturing a perovskite thin film according to an embodiment of the present disclosure includes supplying a perovskite precursor solution onto a substrate, supplying a first additive onto a substrate, and a second additive different from the first additive. and supplying the substrate onto the substrate and annealing the substrate.

According to one embodiment of the present disclosure, the perovskite precursor solution may include a precursor of the perovskite compound and a solvent dissolving the perovskite compound.

The perovskite compound may contain monovalent organic cations, divalent metal cations and halide anions. In one embodiment, the perovskite compound of the present invention may satisfy the following formula.

[Formula 1]

AMX ₃

In Formula 1, A is a monovalent cation and may correspond to an organic ammonium ion, an amidinium group ion, or a combination of an organic ammonium ion and an amidinium group ion.

For example, an organic cation as A may have the formula (R1R2R3R4N)+. In this case, R1 to R4 may correspond to hydrogen, unsubstituted or substituted C1-C20 alkyl, or unsubstituted or substituted aryl.

For example, an organic cation as A may have the formula (R5NH3)+, where R5 may correspond to hydrogen or substituted or unsubstituted C1-C20 alkyl.

For example, an organic cation as A has the formula (R6R7N=CH-NR8R9)+, in which case R6 to R9 may correspond to hydrogen, methyl, or ethyl.

M may be a divalent metal ion. For example, M is Cu ²⁺ , Ni ²⁺ , Co ²⁺ , Fe ²⁺ , Mn ²⁺ , Cr ²⁺ , Pd ²⁺ , Cd ²⁺ , Ge ²⁺ , Sn ²⁺ , Pb ²⁺ and Yb ² metal cations selected from the group consisting of ⁺ and combinations thereof, but are not limited thereto.

X may correspond to a halogen ion. For example, the halogen ion includes, but is not limited to, a halogen ion selected from the group consisting of I-, Br-, F-, Cl-, and combinations thereof.

For example, the perovskite compound is any one or a mixture of two or more selected from CH ₃ NH ₃ PbI ₃ (methylammonium lead iodide, MAPbI ₃ ) and CH(NH ₂ ) ₂ PbI ₃ (formamidinium lead iodide, FAPbI ₃ ). it could be

For example, the perovskite compound may be doped, for example Cs may be doped. As an example, the perovskite compound may correspond to Cs _0.17 FA _0.83 Pb(I _0.8 Br _0.2 ) ₃ .

According to one embodiment according to the present disclosure, the perovskite precursor is a precursor of the above-described perovskite compound, and may correspond to an organic cation, a metal cation, or a halogen anion (X). Organic cations, metal ions, and halide anions contained in the precursor may be the same as the monovalent organic cation (A), divalent metal ion (M), and halide anion (X) described above in the perovskite compound. , a detailed description thereof is omitted.

According to one embodiment according to the present disclosure, the solvent may refer to a polar organic solvent, and may refer to an organic solvent having a solubility of 0.5 M or more, specifically 0.8 M or more, of a perovskite compound under 20° C. and 1 atm pressure. there is. As an example of a solvent that dissolves a perovskite compound, N, N-dimethylacetamide, 1,4-dioxane, diethylamine, ethylacetate, tetrahydrofuran (tetrahydrofuran), pyridine, methanol, ethanol, dichlorobenzene, glycerin and dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF dimethylformamide), gamma-butyrolactone (GBL), 1-methyl-2-pyrrolidone (1-Methyl-2-pyrolidinone), or a mixture thereof.

Examples of the non-solvent include non-polar organic solvents, which include pentane, hexene, cyclohexene, 1,4-dioxene, benzene, toluene, triethyl amine, chlorobenzene, ethylamine, and ethyl ether. , chloroform, ethyl acetate, acetic acid, 1,2-dichlorobenzene, tert-butyl alcohol, 2-butanol, isopropanol, and one or more organic solvents selected from methyl ethyl ketone. The invention is not limited by the non-solvent.

According to one embodiment of the present disclosure, first, a perovskite precursor solution is supplied on a substrate. The perovskite precursor solution may be supplied onto the substrate in a 1-step method or sequentially supplied in a 2-step method in which BX ₂ is first supplied onto the substrate and then AX is supplied onto the substrate. In addition, the step of supplying the perovskite precursor solution onto the substrate includes supplying a non-solvent to the perovskite precursor solution.

Then, a step of supplying the first additive onto the substrate is performed. The first additive is an additive other than the solvent and corresponds to an additive that suppresses wrinkles of the perovskite thin film. Due to the material with low solubility added to the perovskite precursor solution, a difference in crystallization occurs in the surface portion during non-solvent treatment, resulting in wrinkles on the surface. In order to solve this problem, according to an embodiment of the present disclosure, a first additive other than a solvent is supplied onto the substrate. The first additive according to an embodiment of the present disclosure corresponds to formamide. The first additive containing formamide does not have the side effect of generating voids in the perovskite thin film due to the conventional wrinkle improvement method using a solvent, and improves surface wrinkles of the perovskite thin film.

Then, the second additive is supplied onto the substrate. This step may be performed simultaneously with the step of supplying the first additive onto the substrate, or may be performed after that. According to one embodiment of the present disclosure, in the process of supplying a perovskite precursor solution onto a substrate and performing a reaction, the first additive may be supplied onto the substrate, and then the second additive may be supplied onto the substrate. According to one embodiment of the present disclosure, supply of the second additive may proceed after spin coating. In this way, when different additives are sequentially supplied to the perovskite precursor solution, the effect of suppressing wrinkles and voids of the perovskite thin film may be remarkable compared to the case where the additives are added simultaneously.

The second additive according to an embodiment of the present disclosure corresponds to an additive that suppresses voids in the perovskite thin film. When the perovskite thin film is formed, when the spin coating is completed, the surface quickly changes to the perovskite thin film, but the solvent remaining in the solution-state perovskite thin film inside exists, and in the annealing process of heat treatment A problem occurs in that voids are formed inside the perovskite thin film due to evaporation of the remaining solvent. In order to solve this problem, according to an embodiment of the present disclosure, a second additive different from the first additive is supplied to the substrate as an additive other than the solvent. The second additive according to an embodiment of the present disclosure corresponds to MACl. MACl suppresses voids formed inside the perovskite thin film.

According to one embodiment of the present disclosure, the step of supplying the perovskite precursor solution onto the substrate, the step of supplying the first additive onto the substrate, and the step of supplying the second additive onto the substrate may be performed simultaneously or sequentially. can proceed with

Then, the remaining solvent is evaporated by annealing the substrate according to an embodiment of the present disclosure.

8 to 12 are diagrams showing crystallinity, photoluminescence (PL) intensity, and the like of perovskite thin films. Using perovskite thin film (Pristine) manufactured without additives, perovskite thin film manufactured using formamide, perovskite thin film manufactured using MACl, and MF (MACl + Formamide) It is possible to check the surface image, crystallinity, photoluminescence (Photoluminescence, PL) intensity, etc. for each of the perovskite thin films prepared by It can be seen that the physical properties of the perovskite thin film using MF (MACl + Formamide) according to an embodiment of the present disclosure are the most excellent.

13 to 16 show device JV characteristic curves and photostability test results of perovskite thin films fabricated in an atmospheric environment, and FIGS. 17 to 21 show large-area perovskite thin films and devices fabricated in an air environment. The experimental results are shown. The atmospheric environment contains moisture (H ₂ O). Since the solvent used in the perovskite thin film manufacturing process easily combines with moisture contained in the general atmospheric environment, it reduces the solubility of the perovskite precursor solution, resulting in a rough surface with wrinkles and voids, and an unbalanced surface with low crystallinity. to form a thin film. Accordingly, the perovskite thin film manufacturing process environment for forming a uniform thin film with improved wrinkles and voids of the perovskite thin film is mainly performed in an inert gas (eg, N ₂ ) environment from which moisture is removed. However, in the case of a process using nitrogen gas, since the cost is high, there is a limit to the fabrication and commercialization of large-area perovskite.

A perovskite thin film manufacturing method according to an embodiment of the present disclosure includes being made in an atmospheric environment containing moisture (H ₂ O). In order to solve the problems that occur when manufacturing perovskite thin films in an atmospheric environment, formamide is added to the perovskite precursor solution to improve the wrinkles of the perovskite thin film, and MACl is added to Voids formed inside the thin film are improved. MACl improves voids by increasing crystallinity due to strong binding force with a dense mesophase formed as a non-solvent and volatility of MA (Methylammonium) component. Since wrinkles and voids generated in the atmospheric environment are improved, it is possible to manufacture economical large-area perovskite.

As shown in FIGS. 13 to 16, a large-area perovskite thin film using MF (MACl + Formamide) according to an embodiment of the present disclosure is manufactured in a general ambient air. Large-area perovskite thin films manufactured by conventional techniques in an atmospheric environment have problems of low reproducibility and reduced efficiency because of their large area. However, large-area perovskite thin films using MF (MACl + Formamide) show high efficiency due to high light stability of charge and increased reproducibility.

The large-area perovskite thin film manufacturing process according to an embodiment of the present disclosure may be performed as a shearing-coating process in an atmospheric environment. As shown in FIGS. 17 to 21, shear coating injects the perovskite precursor solution between the blade and the substrate, and then uniformly supplies the perovskite precursor solution containing MACl and Formamide onto the substrate. . After the supply of the perovskite precursor solution is complete, it is placed in an anti-solvent bath to form an intermediate phase, and then the perovskite thin film is formed through large-area coating through annealing and cutting processes. will form

According to an embodiment of the present disclosure, a large-area perovskite thin film prepared in an atmospheric environment using MF (MACl + Formamide) is a current (J)-voltage (V) graph, fill factor (FF) and energy It was found to have improved performance over the prior art in terms of conversion efficiency (PCE).

The performance of the optical device was evaluated through the following method.

1) Current-voltage characteristics: using an artificial solar device (ORIEL class A solar simulator, Newport, model 91195A) and a source-meter (source-meter, Kethley, model 2420), JSC) and fill factor (FF) were measured.

2) Photoelectric conversion efficiency (power conversion efficiency, PCE): Perovskite optical devices manufactured through Examples and Comparative Examples under constant temperature and humidity conditions of 1,000 W / ㎡ of sunlight intensity and temperature of 85 ° C. and humidity of 85% were 280 to PCE values were measured by exposure to a light source with a wavelength of 2500 nm.

22 is a surface image of a perovskite thin film according to additives, and FIG. 23 is a side image of a perovskite thin film according to additives. In forming a Cs _0.17 FA _0.83 Pb (I _0.8 Br _0.2 ) ₃ thin film according to an embodiment of the present disclosure, surface and side images of the perovskite thin film were taken while changing the additive. As confirmed in the image, it can be seen that surface wrinkles and internal voids of the perovskite thin film are suppressed when both MACl and formamide are supplied to the perovskite precursor solution.

The previous description of the present disclosure is provided to enable any person skilled in the art to make or use the present disclosure. Various modifications of the present disclosure will be readily apparent to those skilled in the art, and the general principles defined herein may be applied in various modifications without departing from the spirit or scope of the present disclosure. Thus, the present disclosure is not intended to be limited to the examples set forth herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Although the present disclosure has been described in relation to some embodiments in this specification, it should be noted that various modifications and changes may be made without departing from the scope of the present disclosure that can be understood by those skilled in the art to which the present disclosure pertains. something to do. Moreover, such modifications and variations are intended to fall within the scope of the claims appended hereto.

Claims

As a method for producing a perovskite thin film,

supplying a perovskite precursor solution onto a substrate;

supplying a first additive onto the substrate;

supplying a second additive different from the first additive onto the substrate; and

Annealing the substrate

including,

Method for producing perovskite thin film.
According to claim 1,

The step of supplying a perovskite precursor solution on a substrate includes the step of supplying an anti-solvent on the substrate.
According to claim 1,

The first additive corresponds to an additive that suppresses the generation of wrinkles on the surface of the perovskite thin film, perovskite thin film manufacturing method.
According to claim 3,

The second additive corresponds to an additive that suppresses the generation of voids inside the perovskite thin film, perovskite thin film manufacturing method.
According to claim 3,

The first additive corresponds to formamide, perovskite thin film manufacturing method.
According to claim 4,

The second additive corresponds to MACl, perovskite thin film manufacturing method.
According to claim 1,

The perovskite thin film manufacturing method is made in an atmospheric environment (ambient air), perovskite thin film manufacturing method.
According to claim 1,

The perovskite precursor is a method for producing a perovskite thin film containing FA (Formamidinium).
As a perovskite thin film manufacturing device,

A solution supply unit for supplying a perovskite precursor solution onto the substrate;

a first additive supply unit supplying a first additive onto the substrate;

a second additive supply unit supplying a second additive different from the first additive onto the substrate; and

An annealing unit for annealing the substrate

including,

Perovskite thin film manufacturing device.
As a solution containing a perovskite precursor,

perovskite precursors;

A solvent dissolving the perovskite precursor;

A first additive and a second additive different from the first additive

A solution containing
According to claim 10,

wherein the first additive corresponds to formamide and the second additive corresponds to MACl.