WO2018070791A1 - Perovskite nanocrystal thin film, manufacturing method therefor, and light emitting device comprising same - Google Patents

Abstract

The present application relates to a perovskite nanocrystal thin film, a manufacturing method therefor, and a light emitting device comprising the same.

Description

Perovskite nanocrystalline thin film, method for manufacturing the same, and light emitting device including the same

The present application relates to a perovskite nanocrystalline thin film, a method for manufacturing the same, and a light emitting device including the same.

The mega trend of the current display market is shifting from the existing high-efficiency high-resolution display to the high-definition display of high-purity natural color. In view of this, organic light-emitting-based organic light emitting diode (OLED) devices have made rapid progress, and inorganic quantum dot light-emitting LEDs with improved color purity have been actively researched and developed as other alternatives. However, both organic and inorganic quantum dot emitters have inherent limitations in terms of materials.

Conventional organic light emitters have the advantage of high efficiency, but the color spectrum is poor due to the broad spectrum. Inorganic quantum dot light emitters have been known to have good color purity, but since the light emission is due to the quantum size effect, it is difficult to control the quantum dot size uniformly toward the blue side, and thus there is a problem that the color purity falls. In addition, the inorganic quantum dots have a very deep valence band, so that the hole injection barrier in the organic hole injection layer is very large, which makes the hole injection difficult. In addition, the two light emitters are expensive. Therefore, there is a need for a new type of organic-inorganic hybrid light emitter or metal halide light emitter that complements and maintains the disadvantages of organic and inorganic light emitters.

Organic-inorganic hybrid perovskite has low manufacturing cost, simple manufacturing process of perovskite material and light emitting device, organic material, easy to control optical and electrical properties, high charge mobility and mechanical and thermal stability. It can have all the advantages of inorganic materials that have the spotlight academically and industrially.

On the other hand, metal halide perovskite has an organic plane (or an alkali metal plane) and an inorganic plane that are alternately stacked, which is similar to a lamellar structure, so that the exciton can be bound in the inorganic plane. By itself, it can be an ideal light emitter that emits light of very high color purity.

Korean Patent No. 10-1755983 discloses a metal halide perovskite light emitting device and a method of manufacturing the same. Specifically, the present invention discloses a metal halide perovskite light emitting device in which the emission efficiency and the luminance are improved by preventing the exciton disappearing at the perovskite grain boundary by including the organic low molecular weight additive. However, the metal halide perovskite of the registered patent has a high fluorescence efficiency when manufactured in the form of nanocrystals, but it is difficult to form a thin film by dispersing it at a high concentration, and there is a disadvantage that the fluorescence property is greatly reduced due to the aggregation of the nanocrystals. .

The present application is to solve the above-mentioned problems of the prior art, the perovskite nanocrystals are not aggregated, the radiation recombination is fast, thereby emitting light including a perovskite nanocrystal thin film having a high current efficiency and quantum efficiency It is an object to provide an element.

However, the technical problem to be achieved by the embodiments of the present application is not limited to the technical problems as described above, and other technical problems may exist.

As a technical means for achieving the above technical problem, the first aspect of the present application is an adduct comprising a compound represented by the following formula (1) by dissolving an organic halide, a metal halide and a Lewis base compound in a first solvent ( adduct) preparing a complex; Applying the adduct complex on a substrate; Coating by adding a second solvent on the substrate; And vacuum annealing by adding an anti-solvent on the substrate.

[Formula 1]

RMX ₃

(In Formula 1, R is a C _{1- 24} alkyl group, an amine group substituted with an alkyl group, or an alkali metal, M is Pb, Cu, Ni, Co, Fe, Mn, Cr, Pd, Cd, Yb, Sn, Ge, and a metal selected from the group consisting of combinations thereof, wherein X comprises a halide anion or a chalcogenide anion).

According to one embodiment of the present application, the organic halide may be represented by the following Chemical Formula 2, but is not limited thereto.

[Formula 2]

RX

(In the formula 2, R is an alkyl group of _{1- 24} C, and an amine group substituted with an alkyl group, or an alkali metal, X is an anion, including halide, or chalcogenide anion).

According to the exemplary embodiment of the present application, the metal halide may be represented by the following Chemical Formula 3, but is not limited thereto.

[Formula 3]

MX ₂

(In Formula 3, M is a metal selected from the group consisting of Pb, Cu, Ni, Co, Fe, Mn, Cr, Pd, Cd, Yb, Sn, Ge, and combinations thereof, X Is a halide anion or a chalcogenide anion).

According to one embodiment of the present application, the first solvent is dimethylformamide (Dimethylformamide (DMF), gamma-butyrolactone), dimethylacetamide (Dimethylacetamide), N-methylpyrrolidone (N-Methylpyrrolidone ), N-methyl-2-pyridine, pyridine, aniline, and combinations thereof, but is not limited thereto.

According to the exemplary embodiment of the present application, the Lewis base compound may include a functional group having an electron pair donor as an atom having an unshared electron pair, but is not limited thereto.

According to one embodiment of the present invention, the Lewis base compound is dimethylsulfoxide (dimethylsulfoxide (DMSO), H ₂ O, N, N-dimethylacetamide (N, N-Dimethylacetamide), N-methyl-2-pyrrolidinone (N-Methyl-2-pyrrolidione), N-Methyl-2-pyridine, 2,6-dimethyl-γ-pyrone, acetamide (Acetamide), Urea, Thiourea, N, N-dimethylthioacetamide, N, N-Dimethylthioacetamide, Thioacetamide, Ethylenediamine, Tetramethylethylenediamine ), 2,2'-Bipyridine, 1,10-Piperidine, Aniline, Pyrrolidine, Diethylamine ), N-methylpyrrolidine (N-Methylpyrrolidine), may be one or more compounds selected from n-propylamine (n-Propylamine), but is not limited thereto.

According to one embodiment of the present application, the organic halide and the metal halide may be added in a molar ratio of 1: 1 to 10: 1, but is not limited thereto.

According to one embodiment of the present application, the metal halide and the Lewis base compound may be added in a molar ratio of 1: 1 to 1: 5, but are not limited thereto.

According to one embodiment of the present application, the adduct complex may include, but is not limited to, a Lewis acid-base reactant produced by the reaction of the metal halide and the Lewis base compound.

According to one embodiment of the present disclosure, the substrate is indium tin oxide (ITO), fluorine tin oxide (FTO), ZnO-Ga ₂ O ₃ , ZnO-Al ₂ O ₃ , tin oxide, zinc oxide, and their It may include, but is not limited to, a material selected from the group consisting of combinations.

According to one embodiment of the present invention, the substrate is polyethylene terephthalate (Polyethyleneterephthalate), polyethylene naphthalate (Polyethylenenaphthalate), polycarbonate (Polycarbonate), polypropylene (Polypropylene), polyimide (Polyimide), triacetylcellulose (Triacetylcellulose), And it may be to include a polymer substrate selected from the group consisting of, but is not limited thereto.

According to one embodiment of the present application, the second solvent is diethylether, N-methylpyrrolidone, N-Methylpyrrolidone, acetonitrile, acetone, tetrahydrofuran, Tetrahydrofuran, Toluene, 1,2-dichlorobenzene, and combinations thereof may be selected from, but is not limited thereto.

According to one embodiment of the invention, the coating is spin coating, bar coating, nozzle printing, spray coating, slot die coating, gravure printing, inkjet printing, screen printing, electrohydrodynamic jet printing (electrohydrodynamic jet printing), electrospray ( electrospray), and combinations thereof, but is not limited thereto.

According to one embodiment of the present invention, the antisolvent is chloroform (Chloroform), hexene (Hexene), cyclohexene (Cyclohexene), 1,4-dioxene (1,4-Dioxane), benzene (Benzene), toluene (Toluene ), Triethylamine, Chlorobenzene, Ethylamine, Ethylamine, Ethylether, Ethylacetate, Acetic Acid, 1,2-Dichlorobenzene (1) Non-polar selected from the group consisting of 2-Dichlorobenznene, Tert-Butyl alcohol, 2-Butanol, Isopropanol, Methylethylketone, and combinations thereof It may include an organic solvent, but is not limited thereto.

A second aspect of the present disclosure provides a perovskite nanocrystalline thin film, prepared according to any one of the embodiments of the first aspect.

A third aspect of the present application, the first electrode; A hole transport layer formed on the first electrode; A photoactive layer formed on the hole transport layer and including a perovskite nanocrystalline thin film according to a second aspect; An electron transport layer formed on the photoactive layer; And a second electrode formed on the electron transport layer.

According to the aforementioned problem solving means of the present application, the present application can provide a method for producing a perovskite nanocrystalline thin film excellent in current efficiency and quantum efficiency by vacuum annealing the adduct complex to which the Lewis base compound is added.

In addition, by excessively supplying the organic halide in the adduct complex manufacturing step of the present application, the remaining organic halide can be deposited on the perovskite grain boundary to provide a light emitting device having improved electrical characteristics.

The residual organic halide plays an important role in immobilizing the perovskite nanocrystalline thin film surface and constraining excitons on the perovskite grain boundaries.

In addition, by using a cheap raw material, by using a simple and stable low temperature solution process (Spin coating), it is possible to significantly reduce the unit cost, there is an advantage that can be manufactured thin and flexible perovskite nanocrystalline thin film.

The perovskite nanocrystal thin film according to the present invention has a small half width of the fluorescence spectrum (for example, 25 nm), thereby realizing various colors having high color purity.

The light emitting device according to the present invention may bring high current and quantum efficiency compared to a light emitting device manufactured from a conventional perovskite thin film.

The perovskite nanocrystalline thin film of the present application can be utilized for solar power generation alternative materials, electric vehicle charging, silicon solar cell materials and the like.

1 is a flow chart of a method of manufacturing a perovskite nanocrystalline thin film according to an embodiment of the present application.

2 is a schematic diagram of a method for manufacturing a perovskite nanocrystal thin film according to a comparative example of the present application, and b to d of FIG. 2 are permeate transmissions of the perovskite nanocrystalline thin film according to Comparative Examples 1 to 3 of the present application. An electron microscope image.

Figure 3a is a graph showing the XRD spectrum of the perovskite nanocrystal thin film according to Comparative Examples 1 to 4 of the present application, Figure 3b is a wavelength of the perovskite nanocrystalline thin film according to Comparative Examples 1 to 4 of the present application It is a graph showing the absorbance, Figure 3c is a graph showing the photoluminescence intensity according to the wavelength of the perovskite nanocrystal thin film according to Comparative Examples 1 to 4 of the present application, Figure 3d is a Comparative Example 1 to 3 of the present application FIG. 3E is a graph showing the crystallization and charge recombination mechanism of the perovskite nanocrystal thin film according to Comparative Examples 1 and 3 of the present application. to be.

4A is a schematic view illustrating a method of manufacturing a perovskite nanocrystal thin film according to Example 2 of the present application, and FIGS. 4B and 4C are fluorescence images of the perovskite nanocrystal thin film according to Comparative Example 3 and Example 2 of the present application. 4D and 4E are graphs showing photoluminescence intensity over time of the perovskite nanocrystal thin film according to Comparative Example 3 and Example 2 of the present application, and FIGS. 4F and 4G are comparative examples of the present application. 3 and 2 are graphs showing current efficiency according to voltage and quantum efficiency according to luminescence of perovskite nanocrystal thin films according to Example 2.

FIG. 5A is a graph showing Fourier transform infrared (FTIR) spectra of a thin film according to an exemplary embodiment of the present application, and b of FIG. 5 is a graph showing a fingerprint region of stretching vibration of an S = O bond.

Figure 6a is a schematic diagram of a method for producing a perovskite nanocrystal thin film according to the process A, B and C, Figure 6b to 6d is a scanning electron microscope image of the surface of the perovskite nanocrystal thin film according to each process 6E to 6G are scanning electron microscope images of a cross section of the perovskite nanocrystal thin film according to each process.

FIG. 7A is a graph showing XRD spectra of perovskite nanocrystal thin films according to the above processes. FIG. 7B is a graph showing absorbance versus wavelength of the perovskite nanocrystal thin films according to the above processes. Is a graph showing the photoluminescence intensity with respect to the wavelength of the perovskite nanocrystal thin film according to each process.

Figure 8a is a graph showing the XRD spectrum of the perovskite nanocrystal thin film according to Comparative Examples 1 to 4 of the present application, Figure 8b is a graph showing the XRD spectrum of the CH ₃ NH ₃ Br powder and CH ₃ NH ₃ Br thin film. .

9 a to d are ultraviolet (356 nm) light images of the perovskite nanocrystal thin film according to Comparative Examples 1 to 4 herein.

10A to 10D are scanning electron microscope images of general secondary electrons of the perovskite nanocrystal thin film according to Comparative Examples 1 to 4 herein, and e to h of FIG. 10 are compared to Comparative Examples 1 to 4 herein. Scanning electron microscope image of the backscattered electron mode of the perovskite nanocrystal thin film according to the present invention, i to l of FIG. 10 are scanning electrons of energy dispersive spectroscopy of the perovskite nanocrystal thin film according to Comparative Examples 1 to 4 of the present application Microscope image.

11A to 11C are graphs showing ultraviolet photoelectron spectroscopy of perovskite nanocrystalline thin films according to Comparative Examples 1 to 4 and embodiments of the present application, and FIG. 11D is a graph according to Examples 1 and 2 of the present application. It is a graph showing the positions of the conduction band and the valence electron band of the Lobesky nanocrystalline thin film.

12 a and b are topographical maps of the perovskite nanocrystal thin film according to Comparative Examples 1 and 3 of the present application, and c and d of FIG. 12 are perovskite nanocrystalline thin films according to Comparative Examples 1 and 3 of the present application. C-AFM image.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present disclosure. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted for simplicity of explanation, and like reference numerals designate like parts throughout the specification.

Throughout this specification, when a portion is "connected" to another portion, this includes not only "directly connected" but also "electrically connected" with another element in between. do.

Throughout this specification, when a member is said to be located on another member "on", "upper", "top", "bottom", "bottom", "bottom", this means that any member This includes not only the contact but also the presence of another member between the two members.

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

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

As used herein, the terms "about", "substantially", and the like, are used at, or in close proximity to, numerical values when manufacturing and material tolerances inherent in the meanings indicated are provided to aid the understanding herein. In order to prevent the unfair use of unscrupulous infringers. In addition, throughout this specification, "step to" or "step of" does not mean "step for."

Throughout this specification, the term "combination of these" included in the expression of the makushi form means one or more mixtures or combinations selected from the group consisting of constituents described in the expression of the makushi form, wherein the constituents It means to include one or more selected from the group consisting of.

Throughout this specification, description of "A and / or B" means "A, B, or A and B."

Throughout this specification, an "alkyl group" is typically 1 to 24 carbon atoms, 1 to 20 carbon atoms, 1 to 10 carbon atoms, 1 to 8 carbon atoms, 1 to 5 carbon atoms, or 1 to Linear or branched alkyl groups having three carbon atoms. When the alkyl group is substituted with an alkyl group, it is also used interchangeably with "branched alkyl group". Substituents that may be substituted with the alkyl group include halo (eg, F, Cl, Br, I), haloalkyl (eg, CCl ₃ or CF ₃ ), alkoxy, alkylthio, hydroxy, carboxy ( -C (O) -OH), alkyloxycarbonyl (-C (O) -OR), alkylcarbonyloxy (-OC (O) -R), amino (-NH ₂ ), carbamoyl (-NHC Or (O) OR- or -OC (O) NHR-), urea (-NH-C (O) -NHR-) and thiol (-SH). It is not. In addition, an alkyl group having 2 or more carbon atoms in the alkyl group described above may include at least one carbon-to-carbon double bond or at least one carbon-to-carbon triple bond, but is not limited thereto. For example, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl , Eicosanyl, or all possible isomers thereof, but is not limited thereto.

Throughout this specification, the term "halogen" or "halo" means that a halogen atom belonging to group 17 of the periodic table is included in the compound in the form of a functional group, and may be, for example, chlorine, bromine, fluorine or iodine. However, the present invention is not limited thereto.

Hereinafter, the perovskite nanocrystal thin film of the present application, a manufacturing method thereof, and a light emitting device including the same will be described in detail with reference to embodiments, examples, and drawings. However, the present application is not limited to these embodiments, examples and drawings.

In the conventional method for manufacturing a perovskite thin film, there is a problem in that a small and non-uniform perovskite nanocrystal is generated while the solvent vaporizes rapidly during the spin coating process. In addition, the perovskite nanocrystals are agglomerated by heat treatment, which causes a problem of slow photoluminescence collapse time.

Therefore, even when the solvent vaporizes during the spin coating process, the perovskite nanocrystals are maintained without aggregation and development of perovskite nanocrystal thin films with rapid spin recombination is required.

According to a first aspect of the present invention, an organic halide, a metal halide, and a Lewis base compound are dissolved in a first solvent to prepare an adduct complex comprising a compound represented by Formula 1 below; Applying the adduct complex on a substrate; Coating by adding a second solvent on the substrate; And a step of vacuum annealing by adding an anti-solvent on the substrate, to a method for producing a perovskite nanocrystal thin film.

[Formula 1]

RMX ₃

(In Chemical Formula 1,

R is a C _1-24 alkyl group, an amine group substituted alkyl group, or an alkali metal,

M is a metal selected from the group consisting of Pb, Cu, Ni, Co, Fe, Mn, Cr, Pd, Cd, Yb, Sn, Ge, and combinations thereof,

X includes a halide anion or a chalcogenide anion).

Hereinafter, the manufacturing method will be described with reference to FIG. 1.

An organic complex, an metal halide, and a Lewis base compound are dissolved in a first solvent to prepare an adduct complex including a compound represented by Formula 1 below (S100).

[Formula 1]

RMX ₃

(In Formula 1, R is a C _{1- 24} alkyl group, an amine group substituted with an alkyl group, or an alkali metal, M is Pb, Cu, Ni, Co, Fe, Mn, Cr, Pd, Cd, Yb, Sn, Ge, and a metal selected from the group consisting of combinations thereof, wherein X comprises a halide anion or a chalcogenide anion.

In one embodiment of the present disclosure, in Formula 1, R may be a monovalent organic ammonium ion represented by (R ¹ R ² R ³ R ⁴ N) ⁺ , wherein each of R ¹ to R ⁴ independently has carbon number It may include one selected from the group consisting of a linear or branched alkyl group having 1 to 24, a cycloalkyl group having 3 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, and combinations thereof, but is not limited thereto. no.

In one embodiment of the present disclosure, in Formula 1, R may be a monovalent organic ammonium ion represented as (R ⁵ -NH ₃ ) ⁺ , wherein R ⁵ is a linear or branched alkyl group having 1 to 24 carbon atoms, It may include one selected from the group consisting of a cycloalkyl group having 3 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, and combinations thereof, but may not be limited thereto. For example, when R in Formula 1 is (R ⁵ -NH ₃ ) ⁺ , R ⁵ may be a methyl group or an ethyl group. For example, if R ⁵ is a methyl group, R of Formula 1 is (CH ₃ NH ₃₎ ⁺ may be a methyl ammonium (MA) to be displayed as an ion, but is not limited thereto.

In one embodiment of the present application, in Formula 1, R may be represented by Formula (R ⁶ R ⁷ N = CH-NR ⁸ R ⁹ ) ⁺ , wherein R ⁶ is hydrogen, unsubstituted or substituted carbon number An alkyl group having 1 to 20, or an unsubstituted or substituted aryl group; R ⁷ may be hydrogen, an unsubstituted or substituted alkyl group having 1 to 20 carbon atoms, or an unsubstituted or substituted aryl group; R ⁸ is hydrogen, an unsubstituted or substituted alkyl group having 1 to 20 carbon atoms, or unsubstituted and may be an substituted aryl; R ⁹ may be hydrogen, an unsubstituted or substituted alkyl group having 1 to 20 carbon atoms, or an unsubstituted or substituted aryl group, but is not limited thereto. For example, in the cation (R ⁶ R ⁷ N = CH-NR ⁸ R ⁹ ) ⁺ R ⁶ may be hydrogen, a methyl group, or an ethyl group, R ⁷ may be hydrogen, a methyl group, or an ethyl group, R ⁸ May be hydrogen, methyl, or ethyl, and R ⁹ may be hydrogen, methyl, or ethyl, but is not limited thereto. For example, R ⁶ may be hydrogen or a methyl group, R ⁷ may be hydrogen or a methyl group, R ⁸ may be hydrogen or a methyl group, and R ⁹ may be hydrogen or a methyl group, but is not limited thereto. For example, in Formula 1, R is an organic cation represented by Formula (R ⁶ R ⁷ N = CH-NR ⁸ R ⁹ ) ⁺ , and specifically, has a formula of (H ₂ N = CH-NH ₂ ) ⁺ . It may be, but is not limited thereto.

As used herein, an alkyl group may be substituted or unsubstituted and may be linear or branched chain saturated radicals, which may often be substituted or unsubstituted linear chain saturated radicals, for example, Linear chain saturated radicals, but is not limited thereto. For example, an alkyl group having 1 to 20 carbon atoms as used herein may be, but is not limited to, a straight or branched chain saturated hydrocarbon radical, substituted or unsubstituted. For example, an alkyl group as used herein may be an alkyl group having 1 to 10 carbon atoms, that is, a methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, or decyl ), Or an alkyl group having 1 to 6 carbon atoms, that is, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, or a hexyl group, or an alkyl group having 1 to 4 carbon atoms, that is, a methyl group, an ethyl group , i-propyl group, n-propyl group, t-butyl group, s-butyl group, or n-butyl group may be, but is not limited thereto.

When the alkyl group is substituted, the substituent may be one or more substituents selected from, but is not limited thereto: a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group , Cyano group, amino group, C1-C10 alkylamino group, C1-C10 dialkylamino group, arylamino group, diarylamino group , Arylalkylamino group, amide group, acylamide group, hydroxy group, oxo group, halo group, carboxy group, ester ), Acyl group, acyloxy group, alkoxy group having 1 to 20 carbon atoms, aryloxy group, haloalkyl group, sulfonic acid group, Sulfhydryl groups (ie thiol, -SH), alkyl having 1 to 10 carbon atoms Alkylthio group, arylthio group, sulfonyl group, phosphoric acid group, phosphate ester group, phosphonic acid group, and phosphonate ester ester group. For example, the substituted alkyl group may include a halogenalkyl group, a hydroxyalkyl group, an aminoalkyl group, an alkoxyalkyl group, or an alkaryl group, but is not limited thereto. no. The alkaryl group belongs to an alkyl group having 1 to 20 carbon atoms, which means a case where at least one hydrogen atom is substituted with an aryl group. For example, the aryl group replacing the at least one hydrogen atom may be a benzyl group [phenylmethyl, PhCH _2- ], benzhydryl group (Ph ₂ CH-), trityl ( trityl group [triphenylmethyl, Ph ₃ C-], phenethyl group [phenylethyl, Ph-CH ₂ CH _2- ], styryl group (PhCH = CH- ), Or may include a cinnamic group (PhCH = CHCH ₂ −), but is not limited thereto.

For example, when the alkyl group is substituted, the substituent for substituting the alkyl group may be one, two, or three, but is not limited thereto.

As used herein, an aryl group is a monocyclic or bicyclic aromatic group, substituted or unsubstituted, which group is 6 to 14 carbon atoms, preferably 6 to the ring portion. And from 10 to 10 carbon atoms. For example, the aryl group used herein may include, but is not limited to, a phenyl group, a naphthyl group, an indenyl group, and an indanyl group. The aryl group may be substituted or unsubstituted. When the aryl group as defined above is substituted, the substituent may be one or more substituents selected from the following, but is not limited thereto: an unsubstituted alkyl group having 1 to 6 carbon atoms ( Forming an aralkyl group), unsubstituted aryl group, cyano group, amino group, alkylamino group having 1 to 10 carbon atoms, dialkylamino group having 1 to 10 carbon atoms, arylamino group, diaryl Amino group, arylalkylamino group, amide group, acylamide group, hydroxy group, halo group, carboxyl group, ester group, acyl group, acyloxy group, alkoxy group having 1 to 20 carbon atoms, aryloxy group, haloalkyl group, sulf high Drill groups (ie, thiols, -SH), alkylthio groups having 1 to 10 carbon atoms, arylthio groups, sulfonic acid groups, phosphoric acid groups, phosphate ester groups, phosphonic acid groups, and sulfonyl groups. For example, the substituted aryl group may have one, two, or three substituents, but is not limited thereto. For example, a substituted aryl group may be combined with a single C 1-6 alkylene group, or in the formula [-X- (C ₁ -C ₆ ) alkylene], or in the formula [-X- (C ₁ May be substituted at two positions with a bidentate group represented by -C ₆ ) alkylene-X-], wherein X may be selected from O, S, and NR, and R is H, an aryl group, or an alkyl group having 1 to 6 carbon atoms. For example, the substituted aryl group may be a cycloalkyl group or a heteroaryl group fused with a heterocyclyl group. For example, the ring atoms of an aryl group may contain one or more heteroatoms as a heteroaryl group. Such aryl or heteroaryl groups are substituted or unsubstituted mono- or bicyclic heterocyclic aromatic groups, which aromatic group comprises one or more heteroatoms. It may be to include from 6 to 10 atoms in. For example, a ring divided into 5- or 6-parts may include at least one heteroatom selected from O, S, N, P, Se, and Si. For example, one, two, or three heteroatoms may be included. For example, the heteroaryl group may be a pyridyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a furanyl group, a thienyl group , Pyrazolidinyl, pyrrolyl, oxazolyl, oxadiazolyl, isoxazolyl, thiadiazolyl, thiadiazolyl, thiazolyl thiazolyl group, isothiazolyl group, imidazolyl group, pyrazolyl group, quinolyl group, and isoquinolyl group may be included, but is not limited thereto It doesn't happen. For example, the heteroaryl group may not be substituted, and may be substituted as described above with respect to the aryl group, and when substituted, the substituent may be, for example, one, two, or three, but is not limited thereto. .

In one embodiment of the present disclosure, in Formula 1, R may include an alkali metal cation in addition to the organic cation, that is, may include a mixed cation of the organic cation and the alkali metal cation, but is not limited thereto. It doesn't happen. In this case, the molar ratio of the alkali metal cation among all the cations of R in Formula 1 may be greater than 0 to 0.2, but is not limited thereto. The alkali metal cation may include, but is not limited to, a cation of a metal selected from the group consisting of Cs, K, Rb, Mg, Ca, Sr, Ba, and combinations thereof.

In one embodiment of the present application, X in Chemical Formula 1 may be one containing a halide anion or a chalcogenide anion, but is not limited thereto. For example, X in Formula 1 may include one or two or more anions, and more particularly, may include one or more halide anions or one or more chalcogenide anions, or mixed anions thereof. Can be. For example, X in the formula (1) is ^{F -, Cl -, Br -} , I -, S 2-, Se 2 -. Te ^{2 -,} and but can be to include those selected from the group consisting of the combinations thereof, but is not limited thereto. For example, in Formula 1, X is a monovalent halide anion, and may include one or more anions selected from the group consisting of F ⁻ , Cl ⁻ , Br ⁻ , I ⁻ , and combinations thereof, It is not limited to this. For example, X is a divalent chalcogenide anion of the formula ^{1, S 2-, Se 2 -} . Te ^{2 -,} and but can be to include those selected from the group consisting of the combinations thereof, but is not limited thereto.

In one embodiment of the present application, the perovskite compound of Formula 1 is CH ₃ NH ₃ PbI _x Cl _y (real number 0≤x≤3, real number 0≤y≤3, and x + y = 3) , CH ₃ NH ₃ PbI _x Br _y (real number 0≤x≤3, real number 0≤y≤3, and x + y = 3), CH ₃ NH ₃ PbCl _x Br _y (0≤x≤3 real number , Real with 0 ≦ y ≦ 3, and x + y = 3), and CH ₃ NH ₃ PbI _x F _y (real with 0 ≦ _x ≦ ₃ , real with 0 ≦ _y ≦ ₃ , and x + y = 3). One or more may be selected from (CH ₃ NH ₃ ) ₂ PbI _x Cl _y (real number 0≤x≤4, real number 0≤y≤4, and x + y = 4), (CH ₃ NH ₃ ) ₂ PbI _x Br _y (real number 0 ≦ _x ≦ 4, real number 0 ≦ _y ≦ 4, and x + y = 4), (CH ₃ NH ₃ ) ₂ PbCl _x Br _y (0 ≦ _x ≦ Real number 4, real number 0 ≦ _y ≦ 4, and x + y = 4), and (CH ₃ NH ₃ ) ₂ PbI _x F _y (real number 0 ≦ _x ≦ 4, real number 0 ≦ _y ≦ 4, and x + y = 4) may be selected from one or more, but is not limited thereto.

In one embodiment of the present application, the perovskite compound of Formula 1 is CH ₃ NH ₃ PbI ₃ , CH ₃ NH ₃ PbBr ₃ , CH ₃ NH ₃ PbCl ₃ , CH ₃ NH ₃ PbF ₃ , CH ₃ NH ₃ PbBrI ₂ , CH ₃ NH ₃ PbBrCl ₂ , CH ₃ NH ₃ PbIBr ₂ , CH ₃ NH ₃ PbICl ₂ , CH ₃ NH ₃ PbClBr ₂ , CH ₃ NH ₃ PbI ₂ Cl, CH ₃ NH ₃ SnBrI ₂ , CH ₃ NH ₃ SnBrCl ₂ , CH ₃ NH ₃ SnF ₂ Br, CH ₃ NH ₃ SnIBr ₂ , CH ₃ NH ₃ SnICl ₂ , CH ₃ NH ₃ SnF ₂ I, CH ₃ NH ₃ SnClBr ₂ , CH ₃ NH ₃ SnI ₂ Cl, and CH One or more perovskite compounds selected from ₃ NH ₃ SnF ₂ Cl, but is not limited thereto.

For example, a perovskite compound of the formula (I) is _{CH 3 NH 3 PbBrI 2, CH} 3 NH 3 PbBrCl 2, CH 3 NH 3 PbIBr 2, CH 3 NH 3 PbICl 2, CH 3 NH 3 PbClBr 2, CH ₃ NH ₃ PbI ₂ Cl, CH ₃ NH ₃ SnBrI ₂ , CH ₃ NH ₃ SnBrCl ₂ , CH ₃ NH ₃ SnF ₂ Br, CH ₃ NH ₃ SnIBr ₂ , CH ₃ NH ₃ SnICl ₂ , CH ₃ NH ₃ SnF ₂ I It may be, but is not limited to, one or more perovskite compounds selected from CH ₃ NH ₃ SnClBr ₂ , CH ₃ NH ₃ SnI ₂ Cl, and CH ₃ NH ₃ SnF ₂ Cl.

For example, the perovskite compound of Chemical Formula 1 is CH ₃ NH ₃ PbBrI ₂ , CH ₃ NH ₃ PbBrCl ₂ , CH ₃ NH ₃ PbIBr ₂ , CH ₃ NH ₃ PbICl ₂ , CH ₃ NH ₃ PbClBr ₂ , CH One or more perovskite compounds selected from ₃ NH ₃ PbI ₂ Cl, CH ₃ NH ₃ SnF ₂ Br, CH ₃ NH ₃ SnF ₂ I, and CH ₃ NH ₃ SnF ₂ Cl, including but not limited to: no.

For example, the perovskite compound of Chemical Formula 1 is CH ₃ NH ₃ PbBrI ₂ , CH ₃ NH ₃ PbBrCl ₂ , CH ₃ NH ₃ PbIBr ₂ , CH ₃ NH ₃ PbICl ₂ , CH ₃ NH ₃ PbClBr ₂ , CH One or more perovskite compounds selected from ₃ NH ₃ PbI ₂ Cl, CH ₃ NH ₃ SnF ₂ Br, CH ₃ NH ₃ SnF ₂ I, and CH ₃ NH ₃ SnF ₂ Cl, including but not limited to: no.

For example, the perovskite compound of Formula 1 may be selected from CH ₃ NH ₃ PbBrI ₂ , CH ₃ NH ₃ PbBrCl ₂ , CH ₃ NH ₃ PbIBr ₂ , CH ₃ NH ₃ PbICl ₂ , CH ₃ NH ₃ SnF ₂ Br, And one or more perovskite compounds selected from CH ₃ NH ₃ SnF ₂ I, but is not limited thereto.

For example, it is not a perovskite compound of the formula (1) contained in the perovskite nano-crystal thin film in accordance with one embodiment of the present application is CH ₃ NH ₃ PbBr on ₃ days, but limited. The perovskite compound of Chemical Formula 1 has a high light absorption coefficient in exponential unit compared to a general organic dye, and thus exhibits a very good light condensing effect even in a thin film. Accordingly, when the perovskite compound of Chemical Formula 1 is used, a light emitting device Although a thin photoactive layer has a high energy conversion efficiency can be achieved, but is not limited thereto.

In one embodiment of the present application, the organic halide may be represented by Formula 2, but is not limited thereto.

[Formula 2]

RX

More specifically, in the above formula 2, R is a C _{1- 24} alkyl group, an amine group substituted with an alkyl group, or an alkali metal, X is It is however possible that it comprises halide anions or chalcogenide anion, limited to no.

Preferably, the organic halide may be selected from CH ₃ NH ₃ Br, but is not limited thereto.

In one embodiment of the present application, the metal halide may be represented by the following Chemical Formula 3, but is not limited thereto.

[Formula 3]

MX ₂

More specifically, in Formula 3, M includes a metal selected from the group consisting of Pb, Cu, Ni, Co, Fe, Mn, Cr, Pd, Cd, Yb, Sn, Ge, and combinations thereof. And, X may be to include a halide anion or chalcogenide anion, but is not limited thereto.

Preferably, the metal halide may be selected from PbBr ₂ , but is not limited thereto.

In one embodiment of the present invention, the Lewis base compound is dimethyl sulfoxide (Dimethylsulfoxide (DMSO), H ₂ O, N, N-dimethylacetamide (N, N-Dimethylacetamide), N-methyl-2-pyrrolidinone (N-Methyl-2-pyrrolidione), N-Methyl-2-pyridine, 2,6-dimethyl-γ-pyrone, acetamide (Acetamide), Urea, Thiourea, N, N-dimethylthioacetamide, N, N-Dimethylthioacetamide, Thioacetamide, Ethylenediamine, Tetramethylethylenediamine ), 2,2'-Bipyridine, 1,10-Piperidine, Aniline, Pyrrolidine, Diethylamine ), N-methylpyrrolidine (N-Methylpyrrolidine), may be one or more compounds selected from n-propylamine (n-Propylamine), but is not limited thereto.

Preferably, the Lewis base compound may be selected from dimethyl sulfoxide, but is not limited thereto.

According to one embodiment of the present application, the first solvent is dimethylformamide (Dimethylformamide (DMF), gamma-butyrolactone), dimethylacetamide (Dimethylacetamide), N-methylpyrrolidone (N-Methylpyrrolidone ), N-methyl-2-pyridine, pyridine, aniline, and combinations thereof, but is not limited thereto.

Preferably, the first solvent may be selected from dimethylformamide, but is not limited thereto.

According to one embodiment of the present application, the organic halide and the metal halide may be added in a molar ratio of 1: 1 to 10: 1, but is not limited thereto. Preferably, the organic halide and the metal halide may be added in a molar ratio of 1: 1 to 5: 1, but are not limited thereto.

According to one embodiment of the present application, the metal halide and the Lewis base compound may be added in a molar ratio of 1: 1 to 1: 5, but are not limited thereto. Preferably, the metal halide and the Lewis base compound may be added in a molar ratio of 1: 1 to 1: 2, but are not limited thereto.

Subsequently, the adduct complex is applied onto the substrate (S200).

In one embodiment of the present application, the adduct complex is the Lewis base compound is bonded between the organic halide and the metal halide, the crystals are not formed even if the solvent is vaporized by spin coating the adduct complex .

The substrate may be a conductive transparent substrate, for example, indium tin oxide (ITO), fluorine tin oxide (FTO), ZnO-Ga ₂ O ₃ , ZnO-Al ₂ O ₃ , tin oxide, zinc oxide, And it may be to include a glass substrate or a plastic substrate containing a material selected from the group consisting of, but is not limited thereto. Specifically, the substrate may be used without particular limitation as long as it is a material having conductivity and transparency.

For example, the plastic substrate may include one selected from the group consisting of polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polypropylene, polyimide, triacetyl cellulose, and combinations thereof, but is not limited thereto. It is not.

For example, the substrate may include, but is not limited to, doped with a metal selected from the group consisting of Group 3 metals such as Al, Ga, In, Ti, and combinations thereof.

Subsequently, a second solvent is added to the substrate and coated (S300).

The second solvent is diethylether, N-methylpyrrolidone, N-Methylpyrrolidone, Acetonitrile, Acetone, Acetone, Tetrahydrofuran, Toluene, 1,2 -Dichlorobenzene (1,2-Dichlorobenzene), and may be selected from the group consisting of, but is not limited thereto.

Preferably, the second solvent may be selected from diethyl ether, but is not limited thereto.

The second solvent may facilitate the removal of the Lewis base compound on the adduct complex.

The coating may be spin coating, bar coating, nozzle printing, spray coating, slot die coating, gravure printing, inkjet printing, screen printing, electrohydrodynamic jet printing, electrospray, and combinations thereof. It may be selected from the group consisting of, but is not limited thereto. Preferably, the coating may be selected from spin coating, but is not limited thereto.

The spin coating is a method of thinly coating the adduct complex on the substrate by rotating the substrate at high speed, and may rapidly volatilize the second solvent. In addition, the spin coating has an advantage when coating a low viscosity solution.

Subsequently, an anti-solvent is added on the substrate to vacuum annealing (S400).

The anti-solvent refers to a solvent that does not dissolve the perovskite material, such as chloroform, hexene, cyclohexene, 1,4-dioxane, 1,4-dioxane, Benzene, Toluene, Triethylamine, Chlorobenzene, Ethylamine, Ethylamine, Ethylether, Ethylacetate, Acetic Acid, 1 1,2-Dichlorobenznene, Tert-Butyl alcohol, 2-Butanol, Isopropanol, Methylethylketone, and combinations thereof It may be to include a non-polar organic solvent selected from the group consisting of, but is not limited thereto.

Preferably, the anti-solvent may be selected from chloroform, but is not limited thereto.

In one embodiment of the present application, the vacuum annealing may be to dry in a vacuum oven, but is not limited thereto. In this regard, as shown in FIGS. 4F and 4G, the perovskite nanocrystal thin film manufactured by the vacuum annealing process is more efficient than the perovskite nanocrystalline thin film manufactured by the conventional thermal annealing process. The efficiency is improved, and as a result, the effect of improving the performance of the light emitting element can be achieved.

After the vacuum annealing step, the Lewis base compound to which the anti-solvent and the Lewis base compound are combined is removed to form perovskite nanocrystals.

The second aspect of the present application relates to the perovskite nanocrystal thin film manufactured by the manufacturing method according to the first aspect of the present application, and detailed descriptions of portions overlapping with the first aspect of the present application are omitted. The content described with respect to the first aspect of the present application may be equally applied even if the description thereof is omitted in the second aspect of the present application.

Preferably, the perovskite nanocrystal thin film may include a perovskite compound represented by the formula CH ₃ NH ₃ PbBr ₃ , but is not limited thereto.

A third aspect of the present application, the first electrode; A hole transport layer formed on the first electrode; A photoactive layer formed on the hole transport layer and including a perovskite nanocrystalline thin film according to the second aspect of the present application; An electron transport layer formed on the photoactive layer; And a second electrode formed on the electron transport layer.

In one embodiment of the present application, the first electrode may be located on the substrate. The substrate may be a support of the light emitting device, and may be a transparent material, but is not limited thereto. In addition, the substrate may be a flexible material or a hard material, preferably a flexible material. For example, the substrate may be polyethylene terephthalate, polystyrene, polyimide, polyvinyl chloride, polyvinylpyrrolidone, polyethylene, and these It may be selected from the group consisting of the combination of.

In one embodiment of the present application, the first electrode is an electrode injecting holes, may be made of a material of a conductive nature, but is not limited thereto. For example, the first electrode may be selected from the group consisting of graphene, carbon nanotubes, reduced graphene oxide, metal nanowires, metal grids, and combinations thereof. More specifically, it may be a conductive metal oxide. For example, the conductive metal oxide is ITO, AZO (Al-doped ZnO), GZO (Ga-doped ZnO), IGZO (In, Ga-dpoed ZnO), MZO (Mg-doped ZnO), Mo-doped ZnO, Al-doped MgO, Ga-doped MgO, F-doped SnO ₂ , Nbdpoed TiO ₂ , CuAlO ₂ . And it may be selected from a metal oxide consisting of a combination thereof, but is not limited thereto.

In an embodiment of the present disclosure, a deposition process for forming the first electrode may include physical vapor deposition, chemical vapor deposition, sputtering, and pulsed laser deposition. ), Thermal evaporation, electron beam evaporation, atomic layer deposition, or molecular beam epitaxy. According to the exemplary embodiment of the present application, the hole transport layer may include a single molecule hole transport material or a polymer hole transport material, but is not limited thereto.

More specifically, as the single molecule hole transport material, 2,2 ', 7,7'-tetrakis (diphenylamino) -9,9'-spirobifluorene (2,2', 7,7 ' -tetrakis (diphenylamino) -9.9'-spirobifluorene, Spiro-MeOTAD) can be used, and as the polymer hole transport material, polystyrene sulfonate (PEDOT: PSS), poly-hexylthiophene, poly Polytriarylamine, or poly (3,4-ethylenedioxythiophene) (poly (3,4-ethylenedioxythiophene)) may be used, but is not limited thereto. In addition, 4-tert-Butylpyridine, bis (trifluoromethane) sulfonimide lithium salt (Li-TFSI), poly (2-methoxy-5 -(2-ethylhexyloxy) -1,4-phenylenevinylene) (poly (2-methoxy-5- (2-ethylhexyloxy) -1,4-phenylenevinylene)), poly (2,5-bis ( 2-decyl dodecyl) pyrrolo (3,4-c) pyrrole-1,4 (2H, 5H) -dione- (E) -1,2-di (2,2'-bithiophen-5-yl) Poly (2,5-bis (2-decyl dodecyl) pyrrolo (3,4-c) pyrrole-1,4 (2H, 5H) -dione- (E) -1,2-di (2,2 '-bithiophen-5-yl) ethane)) and combinations thereof may be used, but is not limited thereto.

In addition, for example, the hole transport layer may be a dopant selected from the group consisting of Li-based dopants, Co-based dopants, and combinations thereof as the doping material, but is not limited thereto. For example, as the hole transport material, a mixed material of spiro-MeOTAD, Li-TFSI, and tBP may be used, but may not be limited thereto.

In one embodiment of the present application, in relation to the hole transport layer, the hole transport layer may be formed while filling the empty space between the perovskite nanocrystals, but is not limited thereto.

In one embodiment of the present application, the photoactive layer may be one having the perovskite nanocrystals, but is not limited thereto. For example, when the photoactive layer has the perovskite nanocrystals, the problem of hole transfer from the perovskite to the hole transport layer and separation of the perovskite / hole transport layer interface may be improved. Accordingly, the effect of improving the performance of the light emitting device such as photoelectric conversion efficiency can be achieved.

According to one embodiment of the present application, the electron transport layer may be to include a porous metal oxide particle layer, but is not limited thereto. For example, an organic semiconductor, an inorganic semiconductor, or a mixture thereof may be included, but is not limited thereto.

According to an embodiment of the present disclosure, the electron transport layer includes a metal oxide selected from the group consisting of titanium, tin, zinc, tungsten, zirconium, gallium, indium, yttrium, niobium, tantalum, vanadium, and combinations thereof. It may be, but is not limited thereto.

For example, the metal oxide is titanium dioxide (TiO ₂ ), tin oxide (SnO ₂ ), titanium (II) chloride (TiCl ₂ ), zinc oxide (ZnO), copper oxide (II) (CuO), nickel oxide ( II) (NiO), cobalt (II) (CoO), indium oxide (In ₂ O ₃ ), tungsten oxide (WO ₃ ), magnesium oxide (MgO), calcium oxide (CaO), lanthanum oxide (La ₂ O ₃ ), Neodymium oxide (Nd ₂ O ₃ ), yttrium oxide (Y ₂ O ₃ ), cerium oxide (CeO ₂ ), lead oxide (PbO), zirconium oxide (ZrO ₂ ), iron oxide (Fe ₂ O ₃ ), bismuth oxide (Bi ₂ O ₃ ), vanadium pentoxide (V ₂ O ₅ ), vanadium oxide (V) (VO ₂ ), niobium pentoxide (Nb ₂ O ₅ ), cobalt (IV) cobalt (II) (Co ₃ O ₄ ), but may be selected from the group consisting of aluminum (Al ₂ O ₃ ) and combinations thereof, but is not limited thereto. According to the exemplary embodiment of the present disclosure, when the first electrode is an anode, the second electrode may be a cathode.

The second electrode may be selected from the group consisting of metals, alloys, electrically conductive compounds, and combinations thereof having a relatively low work function, but is not limited thereto. For example, the second electrode may be lithium (Li), magnesium (Mg), aluminum (Al), aluminum-lithium (Al-Li), calcium (Ca), magnesium-indium (Mg-In), magnesium-silver (Mg-Ag), and combinations thereof. In addition, the second electrode may use ITO or IZO to obtain a top light emitting device.

Hereinafter, the present invention will be described in more detail with reference to the following examples, but the following examples are for illustrative purposes only and are not intended to limit the scope of the present application.

Example 1 Synthesis of CH ₃ NH ₃ Br

First, a solution of methylamine (30 mL, 40 wt% in methanol) and a solution of hydrogen bromide (50 mL, 48 wt% in water) were mixed and stirred on a round flask with a magnetic stirrer. More specifically, the synthesis reaction proceeded for 2 hours in an ice bath. Thereafter, the solvent was evaporated at 60 ° C. using an evaporator, and the precipitate thus obtained was washed three times with diethyl ether. Thereafter, the washed precipitate was transferred to a beaker and dried in a vacuum oven at 60 ° C. for 24 hours to prepare CH ₃ NH ₃ Br.

Example 2 Preparation of CH ₃ NH ₃ PbBr ₃ Thin Film

Referring to FIG. 4A, first, at room temperature, 3 mmol (336 mg) of CH ₃ NH ₃ Br, 1 mmol of PbBr ₂ (99.999%) and 2 on dimethylformamide (DMF, 494 mg, 99.8%) solution Precursor solution was prepared by dissolving mmol of dimethylsulfoxide (DMSO, 156 mg, Sigma,> 99.9%). The precursor solution was filtered using a 0.45 μm syringe filter. The glass substrate was then washed for 15 minutes in ethanol using ultrasonic waves. The precursor solution was then dropped onto the glass substrate and spin coated for 30 seconds at a speed of 4000 rpm (acceleration = 1000 rpm / s). Thereafter, diethyl ether (0.4 mL) was added dropwise onto the coated glass substrate, followed by spin coating for 10 seconds. Thereafter, chloroform was dropped on the coated CH ₃ NH ₃ PbBr ₃ thin film and dried in a vacuum oven for 10 minutes to form a perovskite nanocrystalline thin film.

Comparative Example 1

First, at room temperature, 1 mmol (112 mg) of CH ₃ NH ₃ Br, 1 mmol of PbBr ₂ (99.999%) and 2 mmol of dimethylsulfoxide (DMSO, on a solution of dimethylformamide (494 mg, 99.8%) 156 mg, Sigma,> 99.9%) was dissolved to prepare a precursor solution. The precursor solution was filtered using a 0.45 μm syringe filter. The glass substrate was then washed for 15 minutes in ethanol using ultrasonic waves. The precursor solution was then dropped onto the glass substrate and spin coated for 30 seconds at a speed of 4000 rpm (acceleration = 1000 rpm / s). Thereafter, diethyl ether (0.4 mL) was added dropwise onto the coated glass substrate, followed by spin coating for 10 seconds. Subsequently, chloroform was added dropwise onto the coated CH ₃ NH ₃ PbBr ₃ thin film, followed by heat treatment at 100 ° C. for 2 minutes, and then heat treatment at 65 ° C. for 1 minute, thereby removing the perovskite nanocrystalline thin film of dimethyl sulfoxide. Was formed.

Comparative Example 2

First, at room temperature, 2 mmol (224 mg) of CH ₃ NH ₃ Br, 1 mmol of PbBr ₂ (99.999%) and 2 mmol of dimethylsulfoxide (DMSO, on a solution of dimethylformamide (494 mg, 99.8%) 156 mg, Sigma,> 99.9%) was dissolved to prepare a precursor solution. The precursor solution was filtered using a 0.45 μm syringe filter. The glass substrate was then washed for 15 minutes in ethanol using ultrasonic waves. The precursor solution was then dropped onto the glass substrate and spin coated for 30 seconds at a speed of 4000 rpm (acceleration = 1000 rpm / s). Thereafter, diethyl ether (0.4 mL) was added dropwise onto the coated glass substrate, followed by spin coating for 10 seconds. Subsequently, chloroform was added dropwise onto the coated CH ₃ NH ₃ PbBr ₃ thin film, followed by heat treatment at 100 ° C. for 2 minutes, and then heat treatment at 65 ° C. for 1 minute, thereby removing the perovskite nanocrystalline thin film of dimethyl sulfoxide. Was formed.

Comparative Example 3

First, at room temperature, 3 mmol (336 mg) of CH ₃ NH ₃ Br, 1 mmol of PbBr ₂ (99.999%) and 2 mmol of dimethylsulfoxide (DMSO, on a solution of dimethylformamide (494 mg, 99.8%) 156 mg, Sigma,> 99.9%) was dissolved to prepare a precursor solution. The precursor solution was filtered using a 0.45 μm syringe filter. The glass substrate was then washed for 15 minutes in ethanol using ultrasonic waves. The precursor solution was then dropped onto the glass substrate and spin coated for 30 seconds at a speed of 4000 rpm (acceleration = 1000 rpm / s). Thereafter, diethyl ether (0.4 mL) was added dropwise onto the coated glass substrate, followed by spin coating for 10 seconds. Subsequently, chloroform was added dropwise onto the coated CH ₃ NH ₃ PbBr ₃ thin film, followed by heat treatment at 100 ° C. for 2 minutes, and then heat treatment at 65 ° C. for 1 minute, thereby removing the perovskite nanocrystalline thin film of dimethyl sulfoxide. Was formed.

[Comparative Example 4]

First, at room temperature, 4 mmol (448 mg) of CH ₃ NH ₃ Br, 1 mmol of PbBr ₂ (99.999%) and 2 mmol of dimethylsulfoxide (DMSO, on a solution of dimethylformamide (494 mg, 99.8%) 156 mg, Sigma,> 99.9%) was dissolved to prepare a precursor solution. The precursor solution was filtered using a 0.45 μm syringe filter. The glass substrate was then washed for 15 minutes in ethanol using ultrasonic waves. The precursor solution was then dropped onto the glass substrate and spin coated for 30 seconds at a speed of 4000 rpm (acceleration = 1000 rpm / s). Thereafter, diethyl ether (0.4 mL) was added dropwise onto the coated glass substrate, followed by spin coating for 10 seconds. Subsequently, chloroform was added dropwise onto the coated CH ₃ NH ₃ PbBr ₃ thin film, followed by heat treatment at 100 ° C. for 2 minutes, and then heat treatment at 65 ° C. for 1 minute, thereby removing the perovskite nanocrystalline thin film of dimethyl sulfoxide. Was formed.

Experimental Example 1

2 is a transmission electron microscope image of the perovskite nanocrystal thin film according to Comparative Examples 1 to 3 of the present application.

Referring to b to d of FIG. 2, as the value of x increases, the color becomes brighter from yellow to green, and the size of the crystal becomes smaller. Specifically, in Comparative Example 1, crystals having a size of 200 nm or more were formed, in Comparative Example 2, crystals having a size of 100 nm to 200 nm were formed, and in Comparative Example 3, crystals having a size of 15 nm were formed, and residuals were formed. CH ₃ NH ₃ Br (yellow arrow in d of FIG. 2) was deposited on the perovskite grain boundary (black arrow in d in FIG. 2).

3A is a graph showing the XRD spectrum of the perovskite nanocrystal thin film according to Comparative Examples 1 to 4 of the present application.

Referring to the upper portion of Figure 3a, it can be seen that the peak intensity decreases as the x value increases.

Referring to the lower part of FIG. 3A, the FWHM (full width-half width) of the peak according to the x value can be confirmed by calculating the peak with a Gaussian distribution function. FWHM at x is 1, 0.16 °, FWHM at x 2 is 0.17 °, FWHM at x 3 is 0.20 °, FWHM at x 4 is 0.23 ° You can see that.

Figure 3b is a graph showing the absorbance according to the wavelength of the perovskite nanocrystal thin film according to Comparative Examples 1 to 4 of the present application.

Referring to FIG. 3B, it can be seen that the perovskite nanocrystal thin films according to Comparative Examples 1 to 4 start absorption at a wavelength of 540 nm. Perovskite nanocrystal thin film according to Comparative Example 4 it can be seen that the absorbance is significantly reduced in the entire wavelength region.

3c is a graph showing the photoluminescence intensity according to the wavelength of the perovskite nanocrystal thin film according to Comparative Examples 1 to 4 of the present application.

Referring to the upper portion of FIG. 3C, the photoluminescence intensity of the perovskite nanocrystal thin film according to Comparative Example 1 is 2.02 × 10 ^5, and the photoluminescence of the perovskite nanocrystal thin film according to Comparative Example 2 The intensity was 6.08 × 10 ^{5, which} was three times higher than the photoluminescence intensity of Comparative Example 1, and the photoluminescence intensity of the perovskite nanocrystal thin film according to Comparative Example 3 was 5.66 × 10 ⁶ . The increase was 28 times compared to the photoluminescence intensity of Example 2. However, the photoluminescence intensity of the perovskite nanocrystal thin film according to Comparative Example 4 was 1.36 × 10 ⁶ , which was lower than that of Comparative Example 3.

3C is a spectrum showing normalized photoluminescence according to wavelengths of the perovskite nanocrystal thin films of Comparative Examples 1 to 4. FIG.

3D is a graph showing photoluminescence intensity over time of the perovskite nanocrystal thin film according to Comparative Examples 1 to 3 of the present application.

Referring to the upper part of FIG. 3D, it can be seen that as the value of x increases, the electron-hole recombination rate increases.

Time constant (τ) for time-luminescence data according to Comparative Examples 1 to 3 of the present application is shown in Table 1 below.

	τ trap	τ bound	τ bulk	τ avg
Comparative Example 1	0.7 ns (24%)	·	22.1 ns (76%)	17.0 ns
Comparative Example 2	·	10.9 ns (88%)	25.6 ns (12%)	12.7 ns
Comparative Example 3	·	6.1 ns (78%)	20.0 ns (22%)	9.2 ns

Table 1 refer to the page lobe perovskite nanocrystal thin film according to the Sky bit Comparing the mean decay charge carriers (τ _avg) of the nano-crystal thin film in Comparative Example 3 according to the Comparative example the τ _avg Is 9.2 ns, τ _avg of the perovskite nanocrystal thin film according to Comparative Example 1 of 17.0 ns And compared to τ _avg of the perovskite nanocrystal thin film according to Comparative Example 2 of 12.7 ns, it is possible to confirm the bright luminescence emission. Τ _bulk Τ _bounds of 10.9 ns and 6.1 ns in addition to the long decay component of (> 20 ns) Can be newly observed.

3D is a graph showing the photoluminescence intensity over time by applying the double exponential reduction formula in the perovskite nanocrystal thin film according to Comparative Example 1.

Figure 3e is a schematic diagram of the crystallization and charge recombination mechanism of the perovskite nanocrystal thin film according to Comparative Examples 1 and 3 of the present application.

Referring to FIG. 3E, in Comparative Example 1 which is a stoichiometric solution, perovskite bulk crystals (> 200 nm) were formed to form a thin film having the perovskite bulk crystals. And i. Comparative Example 3, a non-stoichiometric solution, formed the perovskite nano-sized crystals by remaining CH ₃ NH ₃ Br acting as a surfactant to separate the small nucleus of the adduct complex, which is formed from b to FIG. d and f to h. The perovskite nanocrystals according to Comparative Example 3 can define electron and hole pairs to accelerate the radiation recombination pathway.

Figure 8a is a graph showing the XRD spectrum of the perovskite nanocrystal thin film according to Comparative Examples 1 to 4 of the present application, Figure 8b is a graph showing the XRD spectrum of the CH ₃ NH ₃ Br powder and CH ₃ NH ₃ Br thin film. .

The XRD peak marked * in FIG. 8A corresponds to CH ₃ NH ₃ Br.

9 a to d are ultraviolet (356 nm) light images of the perovskite nanocrystal thin film according to Comparative Examples 1 to 4 herein.

Referring to FIG. 9, as the x value increases, the emission intensity of the perovskite nanocrystal thin film increases.

10A to 10D are scanning electron microscope images of general secondary electrons of the perovskite nanocrystal thin film according to Comparative Examples 1 to 4 herein, and e to h of FIG. 10 are compared to Comparative Examples 1 to 4 herein. Scanning electron microscope image of the backscattered electron mode of the perovskite nanocrystal thin film according to the present invention, i to l of FIG. 10 are scanning electrons of energy dispersive spectroscopy of the perovskite nanocrystal thin film according to Comparative Examples 1 to 4 of the present application Microscope image.

Scale bars in a to l in FIG. 10 represent 100 nm.

The bright areas in e to h in FIG. 10 correspond to CH ₃ NH ₃ PbBr ₃ .

Red dots of i to l in FIG. 10 represent Pb, and CH ₃ NH ₃ PbBr ₃ It can be seen that is sequestered by CH ₃ NH ₃ Br as x value increases.

11A to 11C are graphs showing ultraviolet photoelectron spectroscopy of perovskite nanocrystalline thin films according to Comparative Examples 1 to 4 and embodiments of the present application, and FIG. 11D is a graph according to Examples 1 and 2 of the present application. It is a graph showing the positions of the conduction band and the valence electron band of the Lobesky nanocrystalline thin film.

11A to 11C are prepared in the same manner as in Comparative Example 2, but using a precursor solution containing no PbBr ₂ .

12 a and b are topographical maps of the perovskite nanocrystal thin film according to Comparative Examples 1 and 3 of the present application, and c and d of FIG. 12 are perovskite nanocrystalline thin films according to Comparative Examples 1 and 3 of the present application. C-AFM image.

Referring to a and b of Figure 12, it can be seen that the perovskite nanocrystals according to Comparative Example 3 to maintain a uniform and constant size, which is the residual CH ₃ NH ₃ Br by excess CH ₃ NH ₃ Br supply This is because it was deposited at this perovskite grain boundary.

12 c and d were measured in a dark environment and a bias voltage of 30 mV.

Experimental Example 2

Figure 4a is a schematic diagram of a method for producing a perovskite nanocrystal thin film according to Example 2 of the present application.

4B and 4C are fluorescence images of perovskite nanocrystal thin films according to Comparative Example 3 and Example 2 of the present application.

4B and 4C, it is possible to confirm brighter fluorescent properties in the perovskite nanocrystal thin film according to Example 2 than the perovskite nanocrystal thin film according to Comparative Example 3.

4D and 4E are graphs showing photoluminescence intensity over time of the perovskite nanocrystal thin film according to Comparative Example 3 and Example 2 of the present application.

4D and 4E, it can be seen that the perovskite nanocrystalline thin film according to Example 2 has an improved radiation recombination rate compared to the perovskite nanocrystalline thin film according to Comparative Example 3.

Time constants (τ) for time-luminescence data according to Comparative Example 3 and Example 2 are shown in Table 2 below.

	τ trap	τ bound	τ bulk	τ avg
Comparative Example 3	·	5.9 ns (85%)	22.1 ns (15%)	8.3 ns
Example 2	·	3.9 ns	·	3.9 ns

Referring to [Table 2], it can be seen that the perovskite nanocrystal thin film according to Comparative Example 3 exhibits a double exponential decrease with binary recombination by aggregation of the perovskite nanocrystals. In addition, the perovskite nanocrystalline thin film according to Example 2 can confirm a faster average photoluminescence lifetime than the perovskite nanocrystalline thin film according to Comparative Example 3.

4F and 4G are graphs showing current efficiency according to voltage and quantum efficiency according to luminescence of the perovskite nanocrystal thin film according to Comparative Example 3 and Example 2 of the present application.

4F is an electroluminescence spectrum of the light emitting device, and detailed experimental data of FIGS. 4F and 4G are shown in Table 3 below.

LED parameters	Comparative Example 3	Example 2
Maximum Current Efficiency (cd / A)	4.35	34.36
Max Quantum Efficiency (%)	1.03	8.21
Maximum luminescence (cd / m 2 )	6.38 × 10 2	6.95 × 10 3

Referring to Table 3, the perovskite nanocrystalline thin film according to Example 2 has a maximum current efficiency of 4.35 cd / A to 34.36 cd / A, compared to the perovskite nanocrystalline thin film according to Comparative Example 3. The maximum quantum efficiency is 1.03% to 8.21%, and the maximum luminescence is 6.38 × 10 ² It can be seen that the improvement from cd / m ² to 6.95 × 10 ³ cd / m ² .

Experimental Example 3

FIG. 5A is a graph showing Fourier transform infrared (FTIR) spectra of a thin film according to an exemplary embodiment of the present application, and b of FIG. 5 is a graph showing a fingerprint region of stretching vibration of an S = O bond.

Experimental Example 4

Figure 6a is a schematic diagram of a method for producing a perovskite nanocrystal thin film according to the process A, B and C, Figure 6b to 6d is a scanning electron microscope image of the surface of the perovskite nanocrystal thin film according to each process 6E to 6G are scanning electron microscope images of a cross section of the perovskite nanocrystal thin film according to each process.

More specifically, the step A is a one-step spin coating method using a precursor solution without dimethyl sulfoxide, the step B is a crystallization method using a precursor solution without the dimethyl sulfoxide, the step C is a dimethyl sulfoxide is Adduct approach using a precursor solution.

6B to 6D, it can be seen that the crystal size of the perovskite nanocrystal thin film according to the process C is the finest.

6E to 6G, it can be seen that the cross section of the perovskite nanocrystal thin film according to Process C is the most uniform.

FIG. 7A is a graph showing XRD spectra of perovskite nanocrystal thin films according to the above processes. FIG. 7B is a graph showing absorbance versus wavelength of the perovskite nanocrystal thin films according to the above processes. Is a graph showing the photoluminescence intensity with respect to the wavelength of the perovskite nanocrystal thin film according to each process.

For the absorbance spectrum of FIG. 7B, perovskite nanocrystal thin films according to the above processes were prepared, and the reproducibility of the process could be confirmed.

Example 3 Manufacture of Light-Emitting Element

First, a 120 nm thick ITO substrate having a positive electrode was washed in distilled water and 2-propanol for 30 minutes using ultrasonic waves. Thereafter, after spin-coating a PEDOT: PSS solution, which is a conductive polymer material, on the ITO substrate, heat treatment was performed at 140 ° C. for 10 minutes to form a hole transport layer having a thickness of 60 nm. Thereafter, the CH ₃ NH ₃ PbBr ₃ thin film prepared in Example 2 was deposited on the hole transport layer to form a photoactive layer. Thereafter, 50 nm thick TPBi (1,3,5-Tris (1-Phenyl-1H-benzimidazol-2-yl) benzene) was deposited on the photoactive layer at a high vacuum of 1.0 × 10 ⁻⁷ torr or lower. A transport layer was formed. Thereafter, 1 nm thick LiF and 200 nm thick aluminum were deposited on the electron transport layer to form a negative electrode, thereby manufacturing a light emitting device.

Claims (16)

1. Dissolving an organic halide, a metal halide and a Lewis base compound in a first solvent to prepare an adduct complex comprising a compound represented by Formula 1 below;

   Applying the adduct complex on a substrate;

   Coating by adding a second solvent on the substrate; And

   Vacuum annealing by adding an antisolvent on the substrate;

   Method for producing a perovskite nanocrystalline thin film, comprising:

   [Formula 1]

   RMX ₃

   (In Chemical Formula 1,

   R is an alkyl group of _{1- 24} C, the amine group-substituted alkyl group, or an alkali metal,

   M is a metal selected from the group consisting of Pb, Cu, Ni, Co, Fe, Mn, Cr, Pd, Cd, Yb, Sn, Ge, and combinations thereof,

   X is a halide anion or a chalcogenide anion).
2. The method of claim 1,

   The organic halide is represented by the following formula 2, a method for producing a perovskite nanocrystal thin film:

   [Formula 2]

   RX

   (In Chemical Formula 2,

   R is an alkyl group of _{1- 24} C, the amine group-substituted alkyl group, or an alkali metal,

   X is a halide anion or a chalcogenide anion).
3. The method of claim 1,

   The metal halide is represented by the following formula 3, a method for producing a perovskite nanocrystal thin film:

   [Formula 3]

   MX ₂

   (In Chemical Formula 3,

   M is a metal selected from the group consisting of Pb, Cu, Ni, Co, Fe, Mn, Cr, Pd, Cd, Yb, Sn, Ge, and combinations thereof,

   X is a halide anion or a chalcogenide anion).
4. The method of claim 1,

   The first solvent is dimethylformamide (DMF), gamma-butyrolactone, dimethylacetamide, N-methylpyrrolidone, N-methyl-2- N-Methyl-2-pyridine, Pyridine, Aniline (Aniline), and combinations thereof, The method for producing a perovskite nanocrystalline thin film.
5. The method of claim 1,

   The Lewis base compound is a method for producing a perovskite nanocrystal thin film, which comprises a functional group having an electron-pair donor as an atom having a lone pair.
6. The method of claim 1,

   The Lewis base compound is dimethylsulfoxide (DMSO), H ₂ O, N, N-dimethylacetamide (N, N-Dimethylacetamide), N-methyl-2-pyrrolidione (N-Methyl-2-pyrrolidione ), N-Methyl-2-pyridine, 2,6-dimethyl-γ-pyrone, 2,6-Dimethyl-γ-pyrone, acetamide, urea , Thiourea, N, N-dimethylthioacetamide, N-Dimethylthioacetamide, Thioacetamide, Ethylenediamine, Tetraethylenediamine, 2,2'-bi Pyridine (2,2'-Bipyridine), 1,10-Piperidine, Aniline, Pyrrolidine, Diethylamine, N-methylpyrrolidine (N-Methylpyrrolidine), n-propylamine (n-Propylamine) is one or more compounds selected from, Perovskite nanocrystalline thin film manufacturing method.
7. The method of claim 1,

   The organic halide and the metal halide are added in a molar ratio of 1: 1 to 10: 1, the method of producing a perovskite nanocrystal thin film.
8. The method of claim 1,

   The metal halide and the Lewis base compound are added in a molar ratio of 1: 1 to 1: 5, the method of producing a perovskite nanocrystal thin film.
9. The method of claim 1,

   The adduct complex comprises a Lewis acid-base reactant produced by the reaction of the metal halide and the Lewis base compound, the perovskite nanocrystal thin film manufacturing method.
10. The method of claim 1,

    The substrate is selected from the group consisting of indium tin oxide (ITO), fluorine tin oxide (FTO), ZnO-Ga ₂ O ₃ , ZnO-Al ₂ O ₃ , tin oxide, zinc oxide, and combinations thereof A method for producing a perovskite nanocrystalline thin film, comprising a material.
11. The method of claim 1,

    The substrate is a group consisting of polyethyleneterephthalate, polyethylenenaphthalate, polycarbonate, polypropylene, polyimide, triacetylcellulose, and combinations thereof Comprising a polymeric substrate selected from, Perovskite nanocrystalline thin film manufacturing method.
12. The method of claim 1,

    The second solvent is diethylether, N-methylpyrrolidone, N-Methylpyrrolidone, Acetonitrile, Acetone, Acetone, Tetrahydrofuran, Toluene, 1,2 -Dichlorobenzene (1,2-Dichlorobenzene), and combinations thereof, the method of producing a perovskite nanocrystalline thin film.
13. The method of claim 1,

    The coating may be spin coating, bar coating, nozzle printing, spray coating, slot die coating, gravure printing, inkjet printing, screen printing, electrohydrodynamic jet printing, electrospray, and combinations thereof. Method for producing a perovskite nanocrystalline thin film, which is selected from the group consisting of.
14. The method of claim 1,

    The antisolvent may be chloroform, hexene, cyclohexene, 1,4-dioxene, 1,4-dioxane, benzene, toluene, triethylamine , Chlorobenzene, ethylamine, ethyl ether, ethyl acetate, ethylacetate, acetic acid, 1,2-dichlorobenznene, tert- Butyl alcohol (Tert-Butyl alcohol), 2-butanol (2-Butanol), isopropanol (Isopropanol), methyl ethyl ketone (Methylethylketone), and a non-polar organic solvent selected from the group consisting of a combination thereof, Method for producing a perovskite nanocrystalline thin film.
15. A perovskite nanocrystalline thin film prepared according to the method of any one of claims 1 to 14.
16. A first electrode;

    A hole transport layer formed on the first electrode;

    A photoactive layer formed on the hole transport layer and comprising a perovskite nanocrystalline thin film according to claim 15;

    An electron transport layer formed on the photoactive layer; And

    A second electrode formed on the electron transport layer;

    It comprises a light emitting device.

Images