KR20240074976A - Method for forming quasi-two dimentional perovskite film - Google Patents

Abstract

Preparing a preliminary quasi-two-dimensional perovskite thin film; And a method for forming a quasi-two-dimensional perovskite thin film is provided, comprising the step of coating the preliminary quasi-two-dimensional perovskite thin film by additionally applying a perovskite nanoparticle dispersion solution.
According to the present invention, the luminous efficiency of the device can be effectively improved by helping crystal growth of the perovskite thin film and healing surface defects.

Description

Method for forming quasi-two-dimensional perovskite thin film {METHOD FOR FORMING QUASI-TWO DIMENTIONAL PEROVSKITE FILM}

The present invention relates to a method for forming quasi-two-dimensional perovskite thin films. More specifically, it relates to a method of forming a quasi-two-dimensional perovskite thin film using a perovskite nanoparticle dispersion solution, and a light emitting device and solar cell including the formed perovskite thin film.

Perovskite (ABX ₃ ) is a material with an octahedral structure, where A and B are cations, X is an anion, and when X is composed of a halogen element, it is a halide perovskite. Due to its excellent optical properties, this material is used in many fields such as high-efficiency solar cells, LEDs, and electronic devices. It not only has higher color purity than existing light-emitting layer materials in display devices, but it is also easy to change optical properties and manufacture, attracting attention as a next-generation light emitter. I'm receiving it.

Perovskite can be divided into three-dimensional perovskite with an octahedral inorganic layer (BX ₆ ) structure, two-dimensional perovskite, or quasi-two-dimensional perovskite. 3D perovskites have the problem that it is difficult to adjust their optoelectronic properties due to structural constraints.

Quasi-2D perovskite forms a large space between the octahedral inorganic layers ( _B Divided into slices. The chemical formula of quasi-2D perovskite can be expressed _as L ₂ A _n-1 B _n When A does not exist, BX ₆ forms only one layer, which is a two-dimensional structure with n = 1, and when A exists, BX ₆ forms several layers (n = 2, 3, 4,...) and The layer number becomes n. The large organic cations located at the L site act as spacers and, due to their insulating properties, form a large energy barrier on both sides of the inorganic octahedral structure. As a result, two-dimensional or quasi-two-dimensional perovskites form quantum wells. Therefore, not only is the existence of stable excitons with high formation energy possible depending on the extent to which the physical formation of excitons is limited in the thickness direction, but it is also easy to adjust the band gap and optical/electrical properties according to the number of layers.

However, it is not easy to control the crystal growth of quasi-2D perovskite formed in a thin film. Therefore, there is a need to improve the efficiency of the device by controlling the crystal formation and growth of quasi-2D perovskite.

Patent Document 1 discloses a method of forming a perovskite nanocrystal thin film by applying a solution in which a perovskite material is dissolved on a substrate, adding an anti-solvent to the substrate, and vacuum annealing it. This study presents a perovskite nanocrystal thin film that improves the non-uniformity of the thin film and reduces the number of defects in the thin film.

However, there is a problem that sufficient luminous efficiency cannot be improved even with the above method.

In the present invention, by introducing a perovskite nanoparticle dispersion solution in the process of forming a quasi-2D perovskite thin film, the efficiency of the light emitting device is improved by helping crystal growth of the perovskite light emitting layer thin film and healing surface defects. We want to improve effectively.

Korean Patent No. 10-1908708

One aspect of the present invention is a quasi-two-dimensional perovskite with improved external quantum efficiency and luminous efficiency by preparing a preliminary quasi-two-dimensional perovskite thin film and then coating it by additionally applying a perovskite nanoparticle dispersion solution. The object is to provide a method for forming a skyte thin film.

Another aspect of the present invention is to provide a light emitting device and solar cell with improved device efficiency by including the improved quasi-two-dimensional perovskite thin film in the light emitting layer or photoactive layer.

However, the problem to be solved by the present invention is not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the description below.

In order to achieve the above object, one aspect of the present invention includes preparing a preliminary quasi-two-dimensional perovskite thin film; And providing an improved method of forming a quasi-two-dimensional perovskite thin film, comprising the step of coating the preliminary quasi-two-dimensional perovskite thin film by additionally applying a perovskite nanoparticle dispersion solution. do.

Another aspect of the present invention provides a light emitting device including the improved quasi-two-dimensional perovskite thin film in the light emitting layer.

Another aspect of the present invention provides a solar cell including an improved quasi-two-dimensional perovskite thin film in a photoactive layer.

According to the present invention, the luminous efficiency of the device can be effectively improved by helping crystal growth of the perovskite thin film and healing surface defects.

Figure 1 is a diagram showing the formation process of a perovskite thin film according to a comparative example of the present invention.
Figure 2 is a diagram showing the formation process of a perovskite thin film according to Example 1 of the present invention.
Figure 3 is a diagram showing the formation process of a perovskite thin film according to Example 2 of the present invention.
Figure 4 is an emission spectrum of a perovskite thin film formed according to Examples and Comparative Examples of the present invention.
Figure 5 is a spectrum obtained by time-correlated single photon counting (TCSPC) measurement of a perovskite thin film formed according to an example and a comparative example of the present invention.
Figure 6 is an SEM photograph of perovskite thin films formed according to examples and comparative examples of the present invention.
Figure 7 is a structural diagram of a light-emitting device in which a perovskite thin film formed according to an embodiment of the present invention is applied to the light-emitting layer.
Figure 8 shows device data (EQE, Luminance) of a light-emitting device in which a perovskite thin film formed according to Examples and Comparative Examples of the present invention is applied to the light-emitting layer.

Embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the present invention. However, the present application may be implemented in various different forms and is not limited to the embodiments described herein.

Throughout the specification of the present application, when a part “includes” a certain element, this means that it may further include other elements rather than excluding other elements, unless specifically stated to the contrary.

In this specification, terms such as “consists of” or “comprises” should not be construed as necessarily including all of the various components or steps described in the specification, and only some of the components or steps are included. It may not be possible, or it should be interpreted as including additional components or steps.

The present invention seeks to control the formation and growth of crystals by introducing a perovskite nanoparticle dispersion solution in the process of forming a perovskite thin film. The perovskite thin film obtained through this is applied to light emitting devices or solar cells to improve device efficiency.

First, prepare a preliminary quasi-2D perovskite thin film.

The preliminary quasi-two-dimensional perovskite thin film has a single-phase structure of L _y A _1-y BX ₃ or L ₂ A _{n-1 B n} an integer, y is an integer between 0 and 1) or a multi-phase structure of L _{2 A n-1} B _n It is an alkali metal ion, and L may be an organic ammonium or alkali metal ion whose ion radius is larger than that of A, but is not limited thereto.

_{Specifically , the} A _{or the L is} ^an _organic ^ammonium _, ⁽ _C C(NH ₂ ) ₃ ) ⁿ⁺ , ((C _x H _{2x+1 ) n} NH ₃ ) ₂ (CHNH ₃ ) ⁿ⁺ , ₍ CF ₃ NH ₃ ) ⁿ⁺ , ₍ ( _{C 2} ^{( CFNH} ₃ ^{) n +} _{, ( ( C} (Here, n is an integer greater than 1, and x is an integer greater than 1.)

The B is a metal cation and may be a divalent transition metal, rare earth metal, alkaline earth metal, Pb, Sn, Ge, Ga, In, Al, Sb, Bi, Po, or a combination thereof. The X is a halogen ion and may be Cl, Br, I, or a combination thereof.

The preliminary quasi-two-dimensional perovskite may include a multi-layered structure. The multilayer structure can be determined by the number n of layers of inorganic halide, and the quasi-2D perovskite is composed of perovskite crystals with various n values gathered together, or has a single n value (except n = 1). It may also be made of perovskite crystals.

Spin coating the preliminary quasi-two-dimensional perovskite thin film by applying a perovskite precursor solution on a substrate; It can be prepared by dropping a nucleation inducing solution during the spin coating process and then annealing.

The perovskite precursor solution may be a solution in which one or more AX and BX ₂ , which will be described later, are dissolved and mixed in an organic solvent.

The A is a cation, such as Cesium (Cs ⁺ ), alkylammonium, phenylethylammonium (PEA), naphthylmethy-lammonium (NMA), n-butylammonium (BA), methylammonium (MA), formamidinium (FA), etc. However, it is not limited to this. B may be a metal cation such as lead (Pb ⁺ ) or tin (Sn ⁺ ), but is not limited thereto, and X may be a halide anion such as Chlorine (Cl ^- ), Bromine (Br ^- ), Iodine (I ^- ) It may be, etc.

The organic solvent may include, but is limited to, dimethyl sulfoxide, dimethylformamide, gamma butyrolactone, or N-methylpyrrolidone. It doesn't work.

The perovskite precursor solution may be applied to a substrate that comes into contact with the light-emitting layer during the process of manufacturing a light-emitting device. Examples of the substrate may be an electrode, a hole transport layer, an electron transport layer, or an interface layer, but are not limited thereto. It may also be applied to a separate substrate independently from the light emitting device manufacturing process.

The perovskite precursor solution may be applied to a substrate that comes into contact with the photoactive layer during the solar cell manufacturing process. Examples of the substrate may be an electrode, a hole transport layer, an electron transport layer, or an interface layer, but are not limited thereto. Alternatively, it may be applied to a separate substrate independently of the solar cell manufacturing process.

Coating by applying the perovskite precursor solution onto a substrate includes spin coating, bar coating, nozzle printing, spray coating, slot die coating, gravure printing, inkjet printing, screen printing, electrospray, and these. It may be selected from a group of combinations, but is not limited thereto. For example, spin coating may be performed at 1000 to 7000 rpm for 10 to 120 seconds.

During the process of applying and spin coating the perovskite precursor solution, the nucleation inducing solution is dripped. The nucleation inducing solution may include an anti-solvent or a perovskite nanoparticle dispersion solution.

As the first nucleation inducing solution, the anti-solvent has an appropriate polarity so that it does not dissolve the perovskite crystals, but has the property of washing away the solvent dissolving the precursor used to form the perovskite. It is a solvent that contains mainly anti-solvents such as chlorobenzene, chloroform, diethylether, hexene, cyclohexene, and 1,4-dioxane. ), Benzene, Toluene, Triethylamine, Ethylamine, Ethylether, Ethylacetate, Acetic acid, 1,2-Di Use one selected from 1,2-Dichlorobenznene, Tert-Butyl alcohol, 2-Butanol, Isopropanol, Methylethylketone, and combinations thereof. You can.

If an anti-solvent is dropped during or after spin coating the perovskite precursor mixture solution on the substrate, only the solvent dissolving the perovskite precursor is quickly washed away, creating a dense and uniform perovskite. A thin crystalline film can be formed. The antisolvent induces rapid crystallization of perovskite and inhibits the growth of highly crystalline crystals.

As the second nucleation inducing solution, the perovskite nanoparticle dispersion solution is made by dispersing perovskite nanoparticles in an organic solvent.

The perovskite nanoparticles have a molecular formula of ABX ₃ structure. At the A site are cations MA(CH ₃ NH ₃ ⁺ ), FA(CH(NH ₂ ) ₂ ⁺ ), and Cesium(Cs ⁺ ), and at the B site are metal cations Lead(Pb ⁺ ) and Tin(Sn). ⁺ ), etc. are located, and halide anions such as Chlorine (Cl ^- ), Bromine (Br ^- ), Iodine (I ^- ), etc. are located in the X position.

The organic solvent may include, but is limited to, dimethyl sulfoxide, dimethylformamide, gamma butyrolactone, and N-methylpyrrolidone. That is not the case.

The perovskite nanoparticles can be synthesized by dissolving one or more AX and BX ₂ described below in an organic solvent and then adding oleic acid and octylamine to the solution and dropping it into chloroform.

The A is a cation, such as Cesium (Cs ⁺ ), alkylammonium, phenylethylammonium (PEA), naphthylmethy-lammonium (NMA), n-butylammonium (BA), methylammonium (MA), formamidinium (FA), etc. However, it is not limited to this. B may be a metal cation such as lead (Pb ⁺ ) or tin (Sn ⁺ ), but is not limited thereto, and X may be a halide anion such as Chlorine (Cl ^- ), Bromine (Br ^- ), Iodine (I ^- ) It may be, etc.

The organic solvent may include, but is limited to, dimethyl sulfoxide, dimethylformamide, gamma butyrolactone, or N-methylpyrrolidone. It doesn't work.

The above perovskite nanoparticle synthesis method is only an example, and it does not exclude the use of a solution in which perovskite nanoparticles are synthesized by other methods and dispersed in an organic solvent.

The rate of nucleation and crystal growth can be controlled by dripping the perovskite nanocrystal particle dispersion solution while spin coating the perovskite precursor mixture solution on the substrate.

The concentration of the perovskite nanoparticle dispersion solution is preferably 0.001 to 0.1 mg/mL. It was confirmed that when a nanoparticle dispersion solution in the above concentration range was used, the nucleation control effect was maximized and the efficiency was optimized when applying the thin film to the device. That is, the amount of perovskite nanoparticles used is preferably 0.0001 to 0.01 mg. It was confirmed that there was little effect above 0.05 mg.

After adding the nucleation inducing solution dropwise, a preliminary quasi-two-dimensional perovskite thin film can be prepared by heat treatment.

The perovskite nanoparticle dispersion solution is additionally applied and coated on the preliminary quasi-two-dimensional perovskite thin film prepared above.

The coating step is optionally performed by a method selected from the group consisting of spin coating, bar coating, nozzle printing, spray coating, slot die coating, gravure printing, inkjet printing, screen printing, electrospray, and combinations thereof. It can be applied. Preferably, spin coating method is used.

After spin coating and heat treatment, a quasi-two-dimensional perovskite thin film with improved efficiency can be formed.

Another aspect of the present invention provides a light emitting device including a quasi-two-dimensional perovskite thin film with improved efficiency in the light emitting layer.

For example, in a light-emitting device consisting of an anode/hole transport gun/light-emitting layer/electron transport layer/cathode, the quasi-two-dimensional perovskite thin film with improved efficiency of the present invention can be applied to the light-emitting layer. there is. Optionally, a hole injection layer may be further included between the anode and the hole transport layer, and an electroporation injection layer may be further included between the cathode and the electron transport layer.

In this case, the light-emitting layer containing the quasi-2D perovskite with improved efficiency can bind excitons to the inorganic plane more effectively than the quasi-2D perovskite manufactured by the existing method, thereby improving luminescence. It can be improved.

One embodiment of a method for manufacturing a light emitting device by applying the quasi-two-dimensional perovskite thin film of the present invention is as follows.

Coating a hole transport layer on an anode substrate; Spin coating a perovskite precursor solution on the hole transport layer; Preparing a preliminary quasi-two-dimensional perovskite thin film by dropping a nucleation inducing solution during or after spin coating and annealing; Spin coating a perovskite nanoparticle dispersion solution on the preliminary quasi-two-dimensional perovskite thin film; Forming a quasi-two-dimensional perovskite thin film with improved efficiency by heat treatment; coating an electron transport layer on the quasi-two-dimensional perovskite thin film with improved efficiency; and depositing a cathode on the electron transport layer; It provides a method for manufacturing a perovskite-type light emitting device that can control perovskite crystal growth, including.

The anode substrate may be a glass substrate or a flexible substrate coated with a material selected from the group consisting of indium tin oxide (ITO), indium zinc oxide, and tin fluoride (FTO), but is not limited thereto.

The hole transport layer and hole injection layer are Spiro-OMeTAD, PEDOT:PSS, G-PEDOT, PANI:PSS, PANI:CSA, PDBT, P3HT, PCPDTBT, PCDTBT, PTAA, TFB, PVK, PPV, poly-TPD, MoO ₃ , V ₂ O ₅ , NiO, WO ₃ , CuI, CuSCN, poly(3-methylthiophene), polypyrrole, polyaniline, P-type metal oxide, and combinations thereof, but is limited thereto. That is not the case.

The step of spin coating the perovskite precursor solution on the hole transport layer may be a step of spin coating the perovskite precursor mixture solution on the hole transport layer at 1000 to 7000 rpm for 10 seconds to 120 seconds, and is limited thereto. It doesn't work.

The process of forming a quasi-two-dimensional perovskite thin film with improved efficiency is as described above.

The electron transport layer is 1,3,5-tri(N-phenylbenzimidazol-2-yl)benzene (TPBI), SPW-111, tris(8-quinolinolate)aluminum (Alq3), 2,5- Diaryl silol derivative, perfluorinated compound (PF-6P), 4,7-diphenyl-1,10-phenanthroline (Bphen), diphenylphosphine oxide-4-(triphenylsilylyl)phenyl ( TSPO1), TiO ₂ , ZrO, Al ₂ O ₃ , SnO ₂ , ZnO, WO ₃ , Nb ₂ O ₅ , TiSrO ₃ , TPBi (2,2',2"-(1,3,5-Benzinetriyl)-tris (1-phenyl-1-H-benzimidazole)) and combinations thereof, but are not limited thereto.

The cathode may be a metal such as magnesium, calcium, sodium, potassium, titanium, indium, yttrium, lithium, gadolinium, aluminum, silver, tin, lead, cesium, barium, or an alloy thereof, and LiF/Al , LiO ₂ /Al, LiF/Ca, and BaF ₂ /Ca, etc., but are not limited thereto.

Another aspect of the present invention provides a solar cell including a quasi-two-dimensional perovskite thin film with improved efficiency in a photoactive layer.

For example, in a perovskite solar cell composed of a metal electrode/hole transport gun/photoactive layer/electron transport layer/transparent electrode, the quasi-two-dimensional perovskite thin film with improved efficiency of the present invention is applied to the photoactive layer. This is expected to contribute to increasing efficiency.

Hereinafter, the present invention will be described in detail through examples and comparative examples. However, the following examples are only examples to explain the present invention in more detail and do not limit the scope of the present invention.

[Example]

Preparation Example 1-1: Preparation of PEA2(FAPbBr3)2PbBr4 solution

1) Add 0.2202g of PbBr ₂ (Lead(Ⅱ)bromide), 0.05g of FABr (Formamidinium bromide), 0.0808g of PEABr (Phenethylammonium bromide), 0.0043g of MACl (Methylammonium chloride), and 1ml of DMSO (Dimethyl Sulfoxide) into the vial and mix well. Prepare a PEA ₂ (FAPbBr ₃ ) ₂ PbBr ₄ solution.

Preparation Example 1-2: Formation of a preliminary quasi-two-dimensional perovskite thin film by anti-solvent dropping method

1) Apply PEA ₂ (FAPbBr ₃ ) ₂ PbBr ₄ solution on the prepared substrate and spin-coat i) at 1,000 rpm for 10 seconds and then ii) spin-coat at 5,000 rpm for 60 seconds.

2) 20 seconds after spin coating at 5,000 rpm, drop 100 μL of chlorobenzene. The synthesized thin film is heat treated at 90°C for 5 minutes to form a preliminary quasi-two-dimensional perovskite thin film.

The schematic process of thin film formation according to Preparation Example 1-2 is shown in FIG. 1.

Preparation Example 2-1: Preparation of perovskite nanoparticle dispersion solution

1) Dissolve 0.0367g of PbBr ₂ and 0.0275g of FABr in 0.5mL DMF (dimethylformamide), then add 250μL of oleic acid and 25μL of octylamine.

2) While stirring a beaker containing 8mL chloroform, slowly drop the solution over 30 seconds to synthesize FAPbBr ₃ nanoparticles.

3) Add acetonitrile to the synthesized nanoparticles and obtain nanoparticles using centrifugation (10,000 rpm for 5 min), then discard the upper water and disperse in 4 mL of chlorobenzene.

4) To remove large particles, centrifugation is performed once more at 6,000 rpm for 3 minutes, and the upper water is taken to obtain a perovskite nanoparticle dispersion solution.

5) Dilute by adding chlorobenzene to obtain a perovskite nanoparticle dispersion solution of the desired concentration.

Preparation Example 2-2: Formation of a preliminary quasi-two-dimensional perovskite thin film by dropping a perovskite nanoparticle dispersion solution.

A preliminary quasi-two-dimensional perovskite thin film was prepared in the same manner as Preparation Example 1, except that the previously prepared perovskite nanoparticle dispersion solution was used instead of chlorobenzene in the dripping process. form

Example 1: Formation of quasi-two-dimensional perovskite thin film

An additional 150 μL of the perovskite nanoparticle dispersion solution was applied on the preliminary quasi-two-dimensional perovskite thin film obtained in Preparation Example 1-2 and spin-coated at 7000 rpm for 60 seconds.

The schematic process of thin film formation according to Example 1 is shown in FIG. 2.

Example 2: Quasi-2D perovskite thin film formation

150 μL of the previously prepared perovskite nanoparticle dispersion solution was applied onto the preliminary quasi-two-dimensional perovskite thin film formed by the method of Preparation Example 2-2 and spin-coated at 7000 rpm for 60 seconds.

A schematic process of thin film formation according to Example 2 is shown in FIG. 3.

Manufacturing Example 3: Light-emitting device production

According to the methods of Preparation Example 1-2, Example 1, and Example 2, the quasi-two-dimensional perovskite thin film formation process was utilized to form the light-emitting layer, and each light-emitting device having the structure shown in FIG. 7 was manufactured.

The structure of the device is roughly composed of ITO/PVK/Perovskite film/TPBi/LiF/Al.

ITO was placed as an anode on the glass substrate, and HTL (hole transport layer) and EML (light emitting layer) were formed using spin coating. Specifically, the hole transport layer was prepared by mixing chlorobenzene (CB) (1 ml) and PVK (6 mg) in a 5 ml vial to prepare a PVK solution, then applying 200 uL of the PVK solution on the ITO substrate and spin coating at 1000 rpm for 60 seconds. It was formed by heat treatment at ℃ for 30 minutes. The light-emitting layer was formed as a quasi-two-dimensional perovskite thin film according to the method of Preparation Example 1-2, Example 1, and Example 2. An ETL (electron transport layer) and a cathode were formed on the light emitting layer using a thermal evaporation technique. Specifically, the electron transport layer was deposited with TPBi (2,2',2"-(1,3,5-Benzinetriyl)-tris(1-phenyl-1-H-benzimidazole)) at 0.5Å/s to a thickness of 40nm. The cathode was formed by thermally depositing LiF and Al to a thickness of 1 nm and 100 nm, respectively.

Evaluation Example 1: Evaluation of optical/electrical properties of quasi-2D perovskite thin film

Using the preliminary quasi-two-dimensional perovskite thin film prepared in Preparation Example 1-2 as Comparative Example 1, a quasi-two-dimensional perovskite thin film was produced according to the method of Examples 1 and 2. The characteristics of the family were evaluated.

As shown in Figure 4, the emission spectra of Comparative Example, Example 1, and Example 2 were found to be almost identical.

Figure 5 is a spectrum obtained by time-correlated single photon counting (TCSPC) measurement of thin films according to Comparative Example, Example 1, and Example 2.

Time-resolved PL attenuation measurements showed an improved lifetime from 27.60 ns in Comparative Example to 32.28 ns in Example 1, which is interpreted to be the result of reduced surface defects of the thin film formed according to the method of Example 1 compared to the Comparative Example. (See Figure 5 and Table 1)

Sample τ ₁ (ns) f ₁ (%) τ ₂ (ns) f ₂ (%) τ _average (ns) Comparative example 14.77 74.91 71.61 23.09 27.6 Example 1 16.09 74.7 88.48 22.91 32.28

Figure 6 is an SEM photograph of perovskite thin films formed according to examples and comparative examples of the present invention. Compared to the comparative examples, crystals in Examples 1 and 2 appear to be smaller and more densely formed.

Figure 8 shows device data (EQE, Luminance) of a light-emitting device in which a perovskite thin film formed according to Examples and Comparative Examples of the present invention is applied to the light-emitting layer.

Compared to comparison, both the external quantum efficiency (EQE) and luminance of Examples 1 and 2 were significantly improved. (See Figure 8 and Table 2)

CE/PE/EQE Max
[cd A ^-1 /lm W ^-1 /%] At 1000 nits
CE/PE/EQE
[cd A ^-1 /lm W ^-1 /%] Luminance Max
[cd m ^-2 ] Comparative example 53.88/21.14/ 12.16 51.79/18.69/11.76 3520 Example 1 64.94/24.00/ 14.57 62.15/22.88/14.01 3761 Example 2 74.69/29.33/ 17.11 67.79/27.77/15.50 8588

The present invention provides a perovskite thin film with improved performance by additionally applying and coating a perovskite nanoparticle dispersion solution on the basic quasi-two-dimensional perovskite thin film, and when introducing this, conventional technology is provided. It was confirmed that it exhibited better device characteristics (EQE, maximum luminance).

Claims (10)

Preparing a preliminary quasi-two-dimensional perovskite thin film; and
A method of forming a quasi-two-dimensional perovskite thin film, comprising the step of coating the preliminary quasi-two-dimensional perovskite thin film by additionally applying a perovskite nanoparticle dispersion solution. According to clause 1,
The step of preparing the preliminary quasi-two-dimensional perovskite thin film,
Applying a perovskite precursor solution onto a substrate and spin coating it; And a method of forming a quasi-two-dimensional perovskite thin film, comprising the step of annealing after dripping a nucleation inducing solution during the spin coating process. According to clause 2,
The perovskite precursor solution is a solution in which one or more AX and BX ₂ are dissolved and mixed in an organic solvent , where A is Cesium (Cs ⁺ ) or alkylammonium, and B is lead (Pb ⁺ ) or tin (Sn ⁺ ), wherein X is a halide anion. A method of forming a quasi-two-dimensional perovskite thin film. According to clause 2,
A method of forming a quasi-two-dimensional perovskite thin film, wherein the nucleation inducing solution is an anti-solvent. According to clause 2,
A method of forming a quasi-two-dimensional perovskite thin film, wherein the nucleation inducing solution is a perovskite nanoparticle dispersion solution. According to claim 1 or 5,
A method of forming a quasi-two-dimensional perovskite thin film, wherein the concentration of the perovskite nanoparticle dispersion solution is 0.001 to 0.1 mg/mL. According to clause 2 above,
A method of forming a quasi-two-dimensional perovskite thin film, wherein the substrate is an electrode, a hole transport layer, or an electron transport layer in a light emitting device. According to clause 1,
The coating step is selected from the group consisting of spin coating, bar coating, nozzle printing, spray coating, slot die coating, gravure printing, inkjet printing, screen printing, electrospray, and combinations thereof. , Method for forming quasi-two-dimensional perovskite thin films. A light-emitting device comprising a quasi-two-dimensional perovskite thin film formed according to any one of claims 1 to 8 in a light-emitting layer. A solar cell comprising a quasi-two-dimensional perovskite thin film formed according to any one of claims 1 to 8 as a photoactive layer.