KR20200045585A - Light-emitting diode comprising multidimension perovskite light-emitting layer and preparation method thereof - Google Patents

Abstract

The present invention relates to a light-emitting diode comprising a multi-dimensional perovskite hybrid light-emitting layer made of a multi-dimensional perovskite material and a manufacturing method thereof. The multi-dimensional perovskite hybrid light-emitting layer in the light-emitting diode manufactured according to the present invention improves luminous efficiency by coexisting perovskite nanocrystalline particles and perovskite bulk polycrystalline inside the light-emitting layer to improve charge injection into the light-emitting layer. In addition, since it is possible to implement a multi-color light-emitting device which is difficult to implement in an existing single light-emitting device, a new light-emitting diode can be provided.

Description

Light-emitting diode comprising multi-dimension perovskite light-emitting layer and preparation method thereof

The present invention relates to a light-emitting diode including a hybrid light-emitting layer made of a multi-dimensional perovskite material and a method for manufacturing the same.

Metal halide perovskite (hereinafter, perovskite) is attracting attention as a next generation emitter as the mega trend of the display market moves to a display capable of realizing high-purity, natural colors. The perovskite generally has an ABX ₃ structure, the organic ammonium (RNH ₃ ) cation or monovalent alkali metal ion at the A site, and Pb, Mn, Cu, Ge, Sn, Ni, Co, Fe, Cr at the B site. , Pd, Cd, or Yb is a metal element (alkali metal, alkaline earth metal, transition metal, etc.), and a halogen element is located at X.

Perovskite light-emitting diodes are configurable similar to the structures used in existing organic light-emitting diodes, have higher color purity (~ 20nm) than organic light-emitting diodes (> 40nm) and quantum dot displays (~ 30nm), and are inexpensive raw materials and solutions It has the advantage of having price competitiveness based on fairness.

As such, perovskite having the advantages of color purity and price has been actively researched to improve device luminous efficiency similar to that of a conventional display device, and perovskite light emitting diodes have been reported in earnest. It is predicted that it will soon reach the level of existing organic light emitting diodes and quantum dot diodes, such as the external quantum efficiency (EQE) reaching 14.36% in five years.

Currently, the perovskite light emitting diode has a device structure similar to that of the organic light emitting diode, and the light emitting layer is composed of perovskite, and in the case of a general perovskite light emitting diode, like perovskite bulk polycrystalline thin film or nano crystal It consists of a single-dimensional light-emitting layer made of only one-dimensional material.

There are two main types of methods for forming perovskite emitters. The first is a method of forming a perovskite bulk polycrystalline thin film, and after applying a perovskite precursor solution to a substrate, crystallizing to form a thin film crystal, and mainly 2 or 3 dimensional crystals are formed. The second method is a method of forming a perovskite nanocrystal, and is a method of forming a crystal through a perovskite nanocrystal synthesis in advance, and then applying it on a substrate to form a light emitting layer. It is mainly used to synthesize 0-dimensional, 1-dimensional, low-dimensional nanocrystals such as quantum dots and nanowires.

However, the development of a new light-emitting diode capable of multicolor light emission and excellent light emission characteristics is still in demand.

1. Republic of Korea Patent Publication No. 10-2001-0015084 2. Korean Registered Patent No. 10-1815588

The first object of the present invention is to provide a perovskite light-emitting diode comprising a multi-dimensional perovskite hybrid light-emitting layer made of perovskite materials of different dimensions not previously reported.

A second object of the present invention is to provide a method for manufacturing the perovskite light emitting diode.

In order to achieve the first object, the present invention is a substrate; A first electrode positioned on the substrate; A light emitting layer positioned on the first electrode; And a second electrode positioned on the light emitting layer, wherein the light emitting layer is a multidimensional perovskite hybrid light emitting layer composed of a combination of a perovskite bulk polycrystalline thin film and a perovskite nanocrystalline particle layer. A perovskite light emitting diode characterized by the above is provided.

Also, preferably, the perovskite light emitting diode may include a hole injection layer between the first electrode and the light emitting layer, and an electron transport layer between the light emitting layer and the second electrode.

In addition, preferably, the multi-dimensional perovskite hybrid light emitting layer may be formed by sequentially depositing or simultaneously depositing a perovskite bulk polycrystalline thin film and a perovskite nanocrystalline particle layer.

Also preferably, the perovskite bulk polycrystalline thin film has a three-dimensional structure, ABX ₃ structure, or two-dimensional structure, ABX ₃ , A ₂ BX ₄ , ABX ₄ or A _{n- 1} B _n X _{3n +1} (n Is an integer between 2 and 6), wherein A is an amidinium-based organic material, an organic ammonium material, an organic phosphonium ion, an alkali metal or a transition metal, and B is a transition metal, a rare earth metal, Alkaline earth metal, organic, inorganic, ammonium or a derivative thereof, or a combination thereof, and X may be a halogen element.

In addition, preferably, A is formamidinium, acetamidinium, guamidinium, (CH (NH ₂ ) ₂ , C _x H _{2x +1} (CNH ₃ ), (CH ₃ NH ₃ ) _n , ( (C _x H _{2x + 1} ) _n NH ₃ ) _n (CH ₃ NH ₃ ) _n , R (NH ₂ ) ₂ (where R = alkyl), (C _n H _{2n + 1} NH ₃ ) _n , (CF ₃ NH ₃ ), (CF ₃ NH ₃ ) _n , ((C _x F _{2x + 1} ) _n NH ₃ ) _n (CF ₃ NH ₃ ) _n , ((C _x F _{2x + 1} ) _n NH ₃ ) _n , ( C _n F _{2n + 1} NH ₃ ) _n (where n and x are integers from 1 to 100), Na, K, Rb, Cs, Fr, TI or a combination or derivative thereof, wherein B is Pb, Mn, Cu, Ga, Ge, In, Al, Sb, Bi, Po, Sn, Eu, Yb, Ni, Co, Fe, Cr, Pd, Cd, Ca, Sr, organoammonium, inorganic ammonium, organic cation, or combinations thereof Or a derivative, and X may be Cl, Br, I or a combination thereof.

In addition, in order to achieve the second object, the present invention comprises the steps of forming a first electrode on a substrate; Forming a multidimensional perovskite hybrid light emitting layer composed of a combination of perovskite bulk polycrystal and perovskite nanocrystalline particle layer on the first electrode; And it provides a method of manufacturing a perovskite light emitting diode comprising the step of forming a second electrode on the light emitting layer.

In addition, the present invention comprises the steps of forming a first electrode on the substrate; Forming a hole injection layer on the first electrode; Forming a multidimensional perovskite hybrid light emitting layer composed of a combination of a perovskite bulk polycrystalline thin film and a perovskite nanocrystalline particle layer on the hole injection layer; Forming an electron transport layer on the light emitting layer; And it provides a method of manufacturing a perovskite light-emitting diode comprising the step of forming a second electrode on the electron transport layer.

Also preferably, the forming of the multi-dimensional perovskite hybrid light emitting layer may include preparing a perovskite bulk polycrystalline precursor solution and perovskite nanocrystalline particle solution; Applying the perovskite bulk polycrystalline precursor solution on a first electrode or a hole injection layer; And before the coating of the perovskite bulk polycrystalline precursor solution is completed, the perovskite nanocrystalline particle solution is dropped to form the perovskite bulk polycrystalline and perovskite nanocrystalline particles. It may include the step of coating together.

In addition, preferably, the timing of injecting the nanocrystalline particle solution may be performed within 1 second to 200 seconds after application of the perovskite bulk polycrystalline precursor solution.

Also preferably, the forming of the multi-dimensional perovskite hybrid light emitting layer may include preparing a perovskite bulk polycrystalline precursor solution and perovskite nanocrystalline particle solution; Forming a perovskite bulk polycrystalline thin film by coating the perovskite bulk polycrystalline precursor solution on a first electrode or a hole injection layer; And applying and coating the perovskite nanocrystalline particle solution on the formed perovskite bulk polycrystalline thin film.

Also preferably, the forming of the multi-dimensional perovskite hybrid light emitting layer may include preparing a perovskite bulk polycrystalline precursor and perovskite nanocrystalline particle solution; Forming a perovskite nanocrystalline particle layer by coating the perovskite nanocrystalline particle solution on a first electrode or a hole injection layer; And vacuum depositing the perovskite bulk polycrystalline precursor on the formed perovskite nanocrystalline particle layer.

In addition, preferably, the step of forming the multi-dimensional perovskite hybrid light emitting layer may be performed by simultaneously vapor-depositing perovskite bulk polycrystalline precursor and perovskite nanocrystalline particles.

Also preferably, the perovskite bulk polycrystalline precursor solution can be prepared by dissolving a metal halide perovskite in a polar solvent.

Also preferably, the polar solvent may be selected from dimethylformamide, dimethylsulfoxide, gamma butyrolactone, N-methylpyrrolidone, and isopropyl alcohol.

Also preferably, the perovskite nanocrystalline particle solution includes preparing a first solution in which a metal halide perovskite is dissolved in a polar solvent and a second solution in which a surfactant is dissolved in a non-polar solvent or a polar solvent. ; And mixing the first solution with the second solution to form metal halide perovskite nanocrystalline particles.

Also preferably, the surfactant may include an amine ligand and an organic acid, inorganic ligand, or organic ammonium ligand.

Also preferably, the amine ligand is N, N-diisopropylethylamine, ethylene diamine, hexamethylenetetraamine, methylamine, propyl amine, butylamine, hexylamine, heptylamine, octylamine, norylamine, decylamine , Undecylamine, dodecylamine, hexadecylamine, octadecylamine, oleylamine, benzylamine, N, N, N, N-tetramethyleneethylenediamine, triethylamine, diethanolamine, 2,2- ( Ethylenedioxyl) bis- (ethylamine), 2-methyl-1,5-pentanediamine, 3-methoxytriphenyl-amine, 1,4-phenylenediamine, N, N, N, N-pentamethyl di Ethylene triamine, triethylenetetramine, rhodamine, diethylamine and ethyl diamine,

The organic acid is 4,4'-azobis (4-cyanopaleric acid) (4,4'-Azobis (4-cyanovaleric acid)), acetic acid (Acetic acid), 5-myanosalicyclic acid ( 5-Aminosalicylic acid, Acrylic acid, L-Aspentic acid, 6-Bromohexanoic acid, Promoacetic acid, Dichloro Dichloro acetic acid, ethylenediaminetetraacetic acid, isobutyric acid, itaconic acid, maleic acid, r-maleimidobutyl R-Maleimidobutyric acid, L-Malic acid, 4-Nitrobenzoic acid, 1-Pyrenecarboxylic acid, Hexanoic Hexanoic acid, octanoic acid, decanoic acid, undecanoic acid un decanoic acid, dodecanoic acid, hexadecenoic acid octadecanoic acid, oleic acid, n-hexylphosphonic acid, n-octyl Phosphonic acid, n-decylphosphonic acid, n-dodecylphosphonic acid, n-tetradecylphosphonic acid, n-hexadecylphosphonic acid, n-octadecylphosphonic acid, benzylphosphonic acid and benzhai Drill phosphonic acid, n-aminobenzoic acid,

The organic ammonium ligand is a ligand having an alkyl-X structure, and the alkyl is an acyl alkyl (C _n H _{2n +1} ); Polyhydric alcohols including primary alcohols, secondary alcohols, and tertiary alcohols (C _n H _{2n + 1} OH); Alkylamines including hexadecyl amine, 9-octadecenylamine, and 1-amino-9-octadacene (C ₁₉ H ₃₇ N); It is selected from the group consisting of p-substituted aniline, phenyl ammonium and fluorine ammonium, and X may be Cl, Br or I.

Also, preferably, the step of mixing the first solution with the second solution may use a method selected from spray spraying, dripping finely drop by drop, and dropping dropping at a time. You can.

The deposition methods include evaporation, thermal deposition, flash deposition, laser deposition, chemical vapor deposition, atomic layer deposition, and physics. It can be prepared by physical vapor deposition, physical-chemical co-evaporation deposition, sequential vapor deposition and solution process-assisted thermal deposition. .

According to the present invention, the multidimensional perovskite hybrid light-emitting layer coexists perovskite nanocrystalline particles and perovskite bulk polycrystals inside the light emitting layer to stabilize the surface of the nanocrystalline particles with perovskite bulk polycrystalline ( Surface passivation) can be induced, and excitons can be trapped in nanocrystalline particles to improve device luminous efficiency.

In addition, since the perovskite nanocrystalline particles are used to thin the crystal by dispersing it in an anti-solvent that does not dissolve the crystal, it is possible to coat the existing perovskite bulk polycrystalline thin film. In addition, the perovskite can also be deposited by a vacuum deposition method, through which the perovskite bulk polycrystalline / perovskite nanocrystalline layer or perovskite nanocrystalline / perovskite bulk polycrystalline layer It is possible to form the same layer, and one of the two layers can use one layer as a light emitting layer and another layer as a charge injection layer to improve the luminous efficiency. In addition, it is possible to implement multi-color emission, which was difficult to implement in a conventional single-layer device by using both layers as a light emitting layer.

1 is a schematic view showing a light emitting diode according to an embodiment of the present invention.
2 is a schematic diagram showing the difference between a metal halide perovskite nanocrystalline particle emitter and a metal halide perovskite bulk polycrystalline thin film.
3 is a cross-sectional view of a light emitting diode structure including a multidimensional perovskite hybrid light emitting layer according to an embodiment of the present invention.
4 is a schematic diagram showing an example of various manufacturing methods of a multi-dimensional perovskite hybrid light emitting layer according to an embodiment of the present invention.
Figure 5 is a multi-dimensional perovskite hybrid light-emitting layer prepared by a dripping (dripping) method according to an embodiment of the present invention and a perovskite light-emitting layer of only a solvent that does not contain the perovskite nanocrystalline particles of a comparative example This is a comparison of the electron scanning microscope (SEM).
6 is an electron scanning microscope (SEM) comparison of a multi-dimensional perovskite hybrid light-emitting layer prepared by an over-coating method according to an embodiment of the present invention and a non-overcoated perovskite light-emitting layer of a comparative example It is a picture.
7 is a graph showing photoluminescence (PL) characteristics of a multi-dimensional perovskite hybrid light emitting layer manufactured by a dripping method according to another embodiment of the present invention.
8 is a graph showing photoluminescence (PL) characteristics of a multi-dimensional perovskite hybrid light emitting layer manufactured by an over-coating method according to another embodiment of the present invention.
9 is a photograph showing a multicolor electroluminescence (EL) spectrum of a multi-dimensional perovskite hybrid light emitting layer manufactured according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

While the invention allows for various modifications and variations, specific embodiments thereof are illustrated and illustrated in the drawings, which will be described in detail below. However, it is not intended to limit the invention to the specific forms disclosed, but rather the invention includes all modifications, equivalents, and substitutes consistent with the spirit of the invention as defined by the claims.

When an element, such as a layer, region, or substrate, is referred to as being “on” another component, it will be understood that it may be present directly on the other element or intermediate elements may be present therebetween. .

Although the terms first, second, etc. can be used to describe various elements, components, regions, layers and / or regions, these elements, components, regions, layers and / or regions It will be understood that it should not be limited by these terms.

1. Perovskite Light Emitting Diode

1 is a schematic view showing a light emitting diode according to an embodiment of the present invention.

Referring to FIG. 1, a light emitting diode according to the present invention includes a substrate 10, a first electrode 20, a light emitting layer 30, and a second electrode 40.

The substrate 10 is a support for a light emitting device, and may be a transparent material. In addition, the substrate 10 may be a flexible material or a rigid material, preferably a flexible material. For example, the material of the substrate 10 is, in particular, polyethylene terephthalate (polyethylene terephthalate, PET), polystyrene (polystyrene, PS), polyimide (polyimide, PI), polyvinyl chloride (polyvinyl chloride, PVC), poly It may be polyvinylpyrrolidone (PVP) or polyethylene (PE).

The first electrode 20 may be positioned on the substrate 10.

The first electrode 20 may be a conductive polymer or a conductive metal oxide such as ITO or FTO, but is not limited thereto. For example, the first electrode 20 may be graphene, carbon nanotubes, reduced graphene oxide, metal nanowires, or metal grids.

If a conductive polymer is used as the first electrode 20, a perovskite light emitting layer may be directly formed on the first electrode 20 without additional deposition of a hole injection layer 25. On the other hand, when a type of electrode other than a conductive polymer is used as the first electrode 20, it may be necessary to introduce a hole injection layer 25 on the first electrode 20.

For example, the first electrode 20 is an electrode through which holes are injected, and may be made of a material having a conductive property. For example, the material constituting the first electrode 20 may be a metal oxide. More specifically, it may be a transparent conductive metal oxide. For example, the transparent 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 It may be -doped MgO, Ga-doped MgO, F-doped SnO ₂ , Nb-dpoed TiO ₂ or CuAlO ₂ .

Meanwhile, a hole injection layer 25 may be additionally positioned on the first electrode. The hole injection layer 25 may be made of a hole transporting material, for example, the hole transporting material is 1,3-bis (carbazole-9-yl) benzene (1,3-bis (carbazol-9 -yl) benzene: MCP), 1,3,5-tris (carbazol-9-yl) benzene (1,3,5-tris (carbazol-9-yl) benzene: TCP), 4,4 ', 4 "-Tris (carbazole-9-yl) triphenylamine (4,4 ', 4" -tris (carbazol-9-yl) triphenylamine: TcTa), 4,4'-bis (carbazole-9-yl) Biphenyl (4,4'-bis (carbazol-9-yl) biphenyl: CBP), N, N'-bis (naphthalen-1-yl) -N, N'-bis (phenyl) benzidine (N, N ' -bis (naphthalen-1-yl) -N, N'-bis (phenyl) -benzidine: NPB), N, N'-bis (naphthalen-2-yl) -N, N'-bis (phenyl) -benzidine (N, N'-bis (naphthalen-2-yl) -N, N'-bis (phenyl) -benzidine: β-NPB), N, N'-bis (naphthalen-1-yl) -N, N ' -Bis (phenyl) -2,2'-dimethylbenzidine (N, N'-bis (naphthalen-1-yl) -N, N'-bis (phenyl) -2,2'-dimethylbenzidine: α-NPD), Di- [4,-(N, N-ditolyl-amino) -phenyl] cyclohexane (Di- [4- (N, N-ditolyl-amino) -phenyl] cyclohexane: TAPC), N, N, N ' , N'- Tra-naphthalen-2-yl-benzidine (N, N, N ', N'-tetra-naphthalen-2-yl-benzidine: β-TNB) and N4, N4, N4', N4'-tetra (biphenyl-4 Examples include -yl) biphenyl-4,4'-diamine (TPD15), but are not limited thereto.

Subsequently, a light emitting layer 30 may be positioned on the first electrode 20 or the hole injection layer 25. At this time, the light emitting layer 30 is characterized in that the multi-dimensional perovskite hybrid light-emitting layer composed of a combination of perovskite bulk polycrystalline thin film (bulk polycrystal) and perovskite nanocrystalline particle layer.

Figure 2 is a schematic view showing the difference between the perovskite bulk (Bulk) thin film of the present invention and perovskite nanocrystalline particles.

As shown in FIG. 2 (a), the perovskite bulk thin film is simultaneously formed with crystallization and thin film coating by evaporating the solvent in the process of spin coating the transparent ionic perovskite precursor 1 . Therefore, since the bulk thin film is greatly influenced by thermodynamic parameters such as temperature and surface energy during the thin film forming process, it is composed of very non-uniform and large 3D or 2D polycrystals of hundreds of nm to several mm. A film is formed.

However, as shown in FIG. 2 (b), the perovskite nanocrystalline particles are first crystallized into particles in a nm size region in a colloidal solution and then stably dispersed in a solution using a ligand. Since the nanocrystalline particles are in a state where crystallization is terminated in a solution, when forming a thin film through coating, there is no additional growth of crystals and is not affected by the coating conditions and can form a thin film of nanocrystalline particles of several nm level that maintains high luminous efficiency. You can.

3 is an example of a light emitting diode structure including a multidimensional perovskite hybrid light emitting layer according to an embodiment of the present invention.

As shown in FIG. 3, the multi-dimensional perovskite hybrid light emitting layer may be formed by sequentially or simultaneously depositing a perovskite bulk polycrystal thin film and a perovskite nanocrystalline particle layer.

The multi-dimensional perovskite hybrid light emitting layer according to the present invention coexists perovskite nanocrystalline particles and perovskite bulk polycrystalline inside the light emitting layer to stabilize the surface of nanocrystalline particles with perovskite bulk polycrystalline (surface passivation) ), And excitons are confined in nanocrystalline particles to improve device luminous efficiency.

In addition, the multi-dimensional perovskite hybrid light-emitting layer according to the present invention can form a perovskite nanocrystalline particle layer on a perovskite bulk polycrystalline to produce a light-emitting layer composed of two layers, through which it can be implemented in a single-layer light-emitting layer device It is possible to implement a difficult multicolor light emitting device.

In this case, the multi-dimensional perovskite hybrid light emitting layer 30 may partially play a role of the hole injection layer 25. Although perovskite is a promising material as a luminous material, it has a high potential as a charge carrier such as high carrier mobility and long carrier diffusion length, so it is not only emitting light through crystal size adjustment. In addition, the role can be extended to charge transport. In addition, since the energy level can be easily adjusted through a method such as halide ion exchange in the perovskite unit lattice, it can be used for injecting charge into various light emitting layers.

Therefore, in the multi-dimensional perovskite hybrid light emitting layer of the present invention, the perovskite bulk polycrystalline material having high charge mobility and long exciton diffusion length can also serve as a charge transport layer. In addition, since the perovskite nanocrystalline particles can also serve as a charge transport layer, device efficiency can be improved by promoting hole injection or electron injection into the light emitting layer.

The method for forming the multi-dimensional perovskite hybrid light emitting layer can be formed by various methods, and specific methods are described in detail in the manufacturing method section below.

In the present invention, an electron transport layer 35 may be positioned on the multidimensional perovskite hybrid light emitting layer 300. The electron transport layer 35 is a vacuum deposition method, spin coating method, spray method, dip coating method, bar coating method, nozzle printing method, slot-die coating method, gravure printing method, cast method or Langmuir-Blodjet film method (LB (Langmuir-Blodgett)) may be deposited on the light emitting layer 30 according to a randomly selected method from various known methods such as. At this time, the conditions and the coating conditions during the deposition may vary depending on the target compound, the structure and thermal properties of the target layer, and the like.

As the electron transport layer 35 material, a known electron transport material can be used. For example, 1,3,5-Tris (1-phenyl-1H-benzimidazol-2-yl) benzene (TPBi), 1, 3,5-tri [(3-pyridyl) -phen-3-yl] benzene (TmPyPB), Tris (2,4,6-trimethyl-3- (pyridin-3-yl) phenyl) borane (3TPYMB), Tris (8-hydroxy-quinolinato) aluminium (Alq ₃ ), 3- (4-Biphenyl) -4-phenyl-5-tert-butylphenyl-1,2,4-triazole (TAZ), 4,7-Diphenyl-1, 10-phenanthroline (Bphen), 2,9-Dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP (Bathocuproine)), Bis (10-hydroxybenzo [h] quinolinato) beryllium (BeBq _2- ) 1,3 Known materials such as, 5-tri (p-pyrid-3-yl-phenyl) benzene (TpPyPB) or Bis (2-methyl-8-quinolinolate) -4- (phenylphenolato) aluminium (BAlq) can also be used.

The electron transport layer 35 may have a thickness of about 10 nm to 100 nm. More specifically, it may be 20nm to 50nm. When the thickness of the electron transport layer satisfies the above-described range, excellent electron transport characteristics can be obtained without increasing the driving voltage.

An electron injection layer (not shown) may be formed on the electron transport layer 35. As the electron injection layer forming material, known electron injection materials such as LiF, NaCl, NaF, CsF, Li ₂ O, BaO, BaF ₂ , Cs ₂ CO ₃ or Liq (lithium quinolate) may be used.

The thickness of the electron injection layer may be about 0.1nm to 10nm. More specifically, it may be 0.5nm to 5nm. When the thickness of the electron injection layer satisfies the above range, satisfactory electron injection characteristics can be obtained without a substantial increase in driving voltage.

Next, the second electrode 40 may be positioned on the light emitting layer 30 or the electron transport layer 35 or the electron injection layer. For example, when the first electrode 20 is an anode, the second electrode 40 may be a cathode.

In this case, the second electrode 40 may use a material having a relatively low work function, a metal, an alloy, an electrically conductive compound, or a combination thereof. For example, the second electrode 400 is lithium (Li), magnesium (Mg), aluminum (Al), aluminum-lithium (Al-Li), calcium (Ca), magnesium-indium (Mg-In), Magnesium-silver (Mg-Ag), and the like. In addition, ITO or IZO can be used to obtain a front light emitting device.

2. Manufacturing method of perovskite light emitting diode

Method of manufacturing a perovskite light emitting diode according to an embodiment of the present invention

Forming a first electrode on the substrate;

Forming a multidimensional perovskite hybrid light emitting layer layer in which perovskite bulk polycrystalline and perovskite nanocrystalline particles coexist on the first electrode;

And forming a second electrode on the light emitting layer.

First, the first electrode 20 is formed on the substrate 10 using a deposition process.

Deposition processes for forming the first electrode 20 include physical vapor deposition (PVD), chemical vapor deposition (CVD), sputtering, pulsed laser deposition; PLD), thermal evaporation, electron beam evaporation, atomic layer deposition (ALD) or molecular beam epitaxy (MBE) can be used.

Meanwhile, the first electrode 20 may also have a structure including a conductive layer (not shown) and a surface energy-tuning layer (not shown). Specifically, the surface energy control layer may be located on the conductive layer.

The conductive layer may include a conductive polymer and a first fluorine-based material. The surface energy control layer may include a second fluorine-based material, but may not include a conductive polymer included in the conductive layer. In this case, the first fluorine-based material and the second fluorine-based material may be the same or different from each other.

For example, the conductive polymer may include polythiophene, polyaniline, polypyrrole, polystyrene, polyethylenedioxythiophene, polyacetylene, polyphenylene, polyphenylvinylene, polycarbazole, and two or more different repeating units among them. Coalescence, derivatives thereof, or blends of two or more of these.

The structure of the first electrode, while having excellent conductivity, is easy to control the work function, and can prevent exciton dissociation between the metal halide perovskite light emitting layer and the first electrode, which will be described later, so that the metal halide perovskite Luminance and efficiency of the light emitting device can be maximized.

A hole injection layer 25 may be additionally formed on the first electrode as needed. The hole injection layer 25 is a vacuum deposition method, a spin coating method, a spray method, a dip coating method, a bar coating method, a nozzle printing method, a slot-die coating method, a gravure printing method, a cast method or a Langmuir-Blodjet It may be deposited on the light emitting layer 300 according to a randomly selected method from various known methods such as a film method (Langmuir-Blodgett (LB)). At this time, the conditions and coating conditions at the time of deposition may vary depending on the target compound, the structure of the target layer, and thermal properties.

Next, a multi-dimensional perovskite hybrid light emitting layer 30 may be formed on the first electrode 20 or the hole injection layer 25.

4 is a schematic view showing a process of forming a multi-dimensional perovskite hybrid light emitting layer according to an embodiment of the present invention.

Referring to Figure 4, the multi-dimensional perovskite hybrid light emitting layer forming method is (a) dripping (dripping) method, (b) over-coating (over-coating) method, (c) polycrystalline vacuum deposition method or (d) Simultaneous deposition methods can be used.

Hereinafter, a step of forming a multi-dimensional perovskite hybrid light emitting layer according to the present invention will be described in detail.

(a) Dripping method

The step of forming the multi-dimensional perovskite hybrid light emitting layer 30 is

Preparing a perovskite bulk polycrystalline precursor (1) solution and a perovskite nanocrystalline particle (2) solution;

Coating the perovskite bulk polycrystalline precursor (1) solution on the first electrode 20 or the hole injection layer; And

Before the coating of the perovskite bulk polycrystalline precursor (1) solution is completed, the perovskite nanocrystalline particle (2) solution is dropped to remove the perovskite bulk polycrystalline (1) And coating the perovskite nanocrystalline particles 2 together.

First, a perovskite bulk polycrystalline precursor (1) solution and the perovskite nanocrystalline particle (2) solution are prepared.

The perovskite bulk polycrystalline body 1 and the perovskite nanocrystalline particles 2 may use materials having the same chemical structure or materials having different chemical structures.

The perovskite bulk polycrystalline precursor (1) solution can be prepared by dissolving a metal halide perovskite in a polar solvent (first solution).

At this time, the polar solvent may be selected from dimethylformamide, dimethyl sulfoxide, gamma butyrolactone, N-methylpyrrolidone, and isopropyl alcohol, but is not limited thereto.

For example, the organic-inorganic hybrid perovskite having a three-dimensional crystal structure may be an ABX ₃ structure. In addition, the organic-inorganic hybrid perovskite having a two-dimensional crystal structure is the structure of ABX ₃ , A ₂ BX ₄ , ABX ₄ or A _{n- 1} B _n X _{3n +1} (n is an integer between 2 and 6). You can.

In this case, A is an amidium-based organic material or an organic ammonium material (A is an alkali metal in the case of an inorganic metal halide perovskite), B is a metal material or an organic material, and X is a halogen element.

For example, the amidinium-based organic material may be formamidinium, acetamidinium or guamidinium, and the organic ammonium material is (CH ₃ NH ₃ ) _n , ((C _x H _{2x + 1} ) _n NH ₃ ) _n (CH ₃ NH ₃ ) _n , R (NH ₂ ) ₂ (where R = alkyl), (C _n H _{2n + 1} NH ₃ ) _n , (CF ₃ NH ₃ ), (CF ₃ NH ₃ ) _n , ((C _x F _{2x + 1} ) _n NH ₃ ) _n (CF ₃ NH ₃ ) _n , ((C _x F _{2x + 1} ) _n NH ₃ ) _n , (C _n F _{2n + 1} NH ₃ ) _n and derivatives thereof (n is an integer from 1 to 100, x is an integer from 1 to 3).

In addition, the alkali metal may be Na, K, Rb, Cs or Fr.

In addition, B may be a divalent transition metal, rare earth metal, alkaline earth metal, Pb, Sn, Ge, Ga, In, Al, Sb, Bi, Po, organic material, or a combination thereof. At this time, the transition metal may be, for example, Ge, Sn, Pb, and the rare earth metal may be Eu or Yb, for example. Further, the alkaline earth metal may be, for example, Ca or Sr. In addition, X may be Cl, Br, I or a combination thereof.

On the other hand, such perovskite can be prepared by combining AX and BX ₂ in a certain ratio. That is, the first solution may be formed by dissolving AX and BX ₂ in a polar solvent in a certain ratio. For example, the first solution in which ABX ₃ metal halide perovskite is dissolved can be prepared by dissolving AX and BX ₂ in a polar solvent in a 1: 1 ratio.

The perovskite nanocrystalline particles (2) solution

Preparing a first solution in which a metal halide perovskite is dissolved in a polar solvent and a second solution in which a surfactant is dissolved in a non-polar solvent or a polar solvent; And

And mixing the first solution with the second solution to form metal halide perovskite nanocrystalline particles.

First, the method for preparing the first solution is the same as the method for preparing the perovskite bulk polycrystalline precursor solution described above, and thus detailed description is omitted.

The second solution is prepared by dissolving a surfactant in a non-polar solvent or a polar solvent.

The non-polar solvent is selected from methanol, ethanol, tert-butanol, xylene, toluene, hexane, cyclohexene, dichloroethylene, trichloroethylene, chloroform, chlorobenzene, xylene, toluene, hexane, cyclohexene and dichlorobenzene. The polar solvent may be selected from dimethylformamide, dimethylsulfoxide, gamma butyrolactone, N-methylpyrrolidone, and isopropyl alcohol, but is not limited thereto.

The surfactant may include an amine ligand, an organic acid, an organic ammonium ligand, or an inorganic ligand.

The amine ligand is N, N-diisopropylethylamine, ethylene diamine, hexamethylenetetraamine, methylamine, N, N, N, N-tetramethyleneethylenediamine, triethylamine, diethanolamine, 2,2- (Ethylenedioxyl) bis- (ethylamine), 2-methyl-1,5-pentanediamine, 3-methoxytriphenyl-amine, 1,4-phenylenediamine, N, N, N, N-pentamethyl Diethylenetriamine, triethylenetetramine, rhodamine, diethylamine, and ethyllinediamine may be selected from, but are not limited to.

The organic acid includes carboxylic acid and phosphonic acid, and the carboxylic acid is 4,4'-azobis (4-cyanopaleric acid) (4,4'-Azobis (4-cyanovaleric acid)), acetic acid Acetic acid, 5-Aminosalicylic acid, Acrylic acid, L-Aspentic acid, 6-Brohexanoic acid (6- Bromohexanoic acid, promoacetic acid, dichloro acetic acid, ethylenediaminetetraacetic acid, isobutyric acid, itaconic acid ), Maleic acid, r-Maleimidobutyric acid, L-Malic acid, 4-Nitrobenzoic acid, 1- 1-Pyrenecarboxylic acid, hexanoic acid, octanoic acid noic acid, decanoic acid, undecanoic acid, dodecanoic acid, hexadecenoic acid octadecanoic acid and octadecanoic acid Oleic acid (oleic acid) is selected from,

The phosphonic acid is n-hexylphosphonic acid, n-octylphosphonic acid, n-decylphosphonic acid, n-dodecylphosphonic acid, n-tetradecylphosphonic acid, n-hexadecylphosphonic acid, n -Octadecylphosphonic acid, benzylphosphonic acid and benzhydrylphosphonic acid.

The organic ammonium ligand is a ligand having an alkyl-X structure, and the alkyl is an acyl alkyl (C _n H _{2n +1} ); Polyhydric alcohols including primary alcohols, secondary alcohols, and tertiary alcohols (C _n H _{2n + 1} OH); Alkylamines including hexadecyl amine, 9-octadecenylamine, and 1-amino-9-octadacene (C ₁₉ H ₃₇ N); It is selected from the group consisting of p-substituted aniline, phenyl ammonium and fluorine ammonium, and X may be Cl, Br or I.

The step of mixing the first solution with the second solution to form nanocrystalline particles includes spray spraying the second solution onto the second solution, dripping the droplets finely, and dropping them at a time. It can be mixed using a method such as dropping. In addition, the second solution at this time can be stirred. For example, an organic-inorganic perovskite (OIP) is dissolved in a second solution in which a strongly stirred amine ligand and an organic acid (carboxylic acid or phosphonic acid), an organic ammonium ligand, or an inorganic ligand surfactant are dissolved. The second solution may be slowly added dropwise to synthesize nanocrystalline particles.

In this case, when the first solution is dropped and mixed with the second solution, organic-inorganic perovskite (OIP) is precipitated in the second solution due to a difference in solubility. Amine-based ligand pre-mixed in the second solution adheres to the perovskite crystal structure, thereby reducing the difference in solubility to prevent rapid precipitation of perovskite. In addition, the organic-inorganic perovskite (OIP) precipitated in the second solution is attached to the surface through a ionic surfactant or a phosphonic acid surfactant to stabilize the nanocrystals while stabilizing the nanocrystals. Nanocrystals (OIP-NC). Accordingly, it is possible to manufacture organic-inorganic perovskite nanocrystalline particles including organic-inorganic perovskite nanocrystals and a plurality of inorganic or organic ligands surrounding the organic-inorganic perovskite nanocrystals.

However, when the compatibility between the first solution and the second solution is high, recrystallization may not occur, and in this case, a demulsifier may be additionally added.

As the demulsifying agent, tert-butanol may be used, but is not limited thereto.

The thus prepared perovskite nanocrystalline particle solution is a colloidal solution in which perovskite nanocrystalline particles are dispersed in a solvent.

At this time, since the perovskite nanocrystalline particle solution contains unreacted substances and can be dissolved again by a polar solvent containing the generated nanocrystalline particle, after preparation to maintain the shape of the nanocrystalline particle The step of redispersing the non-polar solvent by separating only the nanocrystalline particles by centrifugation or the like may be further performed.

At this time, the nanocrystalline particles may be spherical, cylindrical, elliptical, two-dimensional plate-like, one-dimensional linear or polygonal.

In addition, the average particle size of the nanocrystalline particles may be 1 nm to 50 nm, but the diameter of 10 nm to 30 nm, which is a region not affected by the quantum confinement effect, is larger than the Bohr diameter. It is desirable to have. On the other hand, the size of the nano-crystalline particles at this time refers to a size that does not take into account the length of the ligand, that is, the size of the remaining portion excluding these ligands. The size of the nanoparticles can be measured through a transmission electron microscope (TEM) or dynamic light scattering (DLS) method.

The nanocrystalline particles having a diameter of 10 nm to 30 nm according to the present invention are characterized in that the band gap energy is determined by the structure of the perovskite crystal unlike that of the inorganic quantum dot emitter depending on the particle size according to the quantum confinement effect. Is done.

If the size of the nanocrystalline particles exceeds 30 nm, the exciton binding energy decreases, and the exciton does not go into luminescence due to thermal ionization and delocalization of the charge carrier at room temperature, and the luminous efficiency is reduced due to separation due to free charge. Can be reduced.

On the other hand, if the nanocrystalline particles have a bore diameter of less than, for example, a size of less than 10 nm, the band gap is changed by the size of the chair. The bore diameter may vary depending on the structure of the material, but since it is generally 10 nm or more, in the case of less than 10 nm, the emission wavelength may be changed even if it has the same perovskite structure.

In addition, the band gap energy of these nanocrystalline particles may be 1 eV to 5 eV.

Therefore, since the energy band gap is determined according to the constituent material or crystal structure of the nanocrystalline particles, by controlling the constituent materials of the nanocrystalline particles, light having a wavelength of, for example, 200 nm to 1300 nm can be emitted.

Next, the perovskite bulk polycrystalline (1) precursor solution is coated on the first electrode to be coated.

At this time, the first electrode may be rotated to uniformly apply the perovskite bulk polycrystalline (1) precursor solution on the first electrode.

The rotational speed is preferably 1000 to 8000 rpm, and if it is less than 1000 rpm, there is a problem in uniform film formation, and if it exceeds 8000 rpm, there is a problem in uniform crystal growth as the evaporation of the solvent becomes remarkably faster. There is a problem in forming a multi-dimensional perovskite light emitting layer because injection of lobsky nanocrystalline particles is difficult.

In an embodiment of the present invention, the perovskite bulk polycrystalline (1) precursor solution was applied and coated while rotating the first electrode at 3000 rpm.

The coating may be made of spin coating, bar coating, nozzle printing, spray printing, slot die coating, gravure printing, inkjet printing, screen printing, electrohydrodynamic jet printing or electrospray.

Next, before the coating of the perovskite bulk polycrystalline (1) precursor solution is completed, the perovskite nanocrystalline particles (2) are injected (dripping) the solution to perovskite Bulk polycrystalline and perovskite nanocrystalline particles are coated together.

At this time, the time when the coating of the perovskite bulk polycrystalline (1) precursor solution is completed is crystallized by evaporation of the solvent of the perovskite bulk polycrystalline (1) precursor solution (precursor) It is made, and the color of the thin film is changed. Therefore, the point of dropping the solution of the perovskite nanocrystalline particles 2 is preferably performed within 1 second to 200 seconds after application of the perovskite bulk polycrystalline precursor solution.

In one embodiment of the present invention, the perovskite nanocrystalline particles (2) solution was dropped and coated together 20 seconds after application of the perovskite bulk polycrystalline (1) precursor solution.

After coating, heat treatment may be performed to increase the density of the thin film.

The heat treatment may be performed at 80-120 ° C.

In one embodiment of the present invention, the prepared hybrid thin film was heat treated at 90 ° C for 10 minutes.

As shown in FIG. 5, the hybrid thin film coated with the perovskite bulk polycrystalline (1) precursor solution and the perovskite nanocrystalline particle (2) solution is a perovskite nanocrystal. It has been shown to act as a crystallization seed, providing many crystallization sites, thereby inducing a granular structure of the thin film. Therefore, compared to the conventional single-dimensional light-emitting layer made of only one-dimensional material, it can exhibit significantly improved light emission intensity (see FIG. 7).

The formed multi-dimensional perovskite hybrid light emitting layer may have a thickness of 10 nm to 10 μm.

In addition, the emission wavelength of the multidimensional perovskite hybrid light emitting layer may be 200 nm to 1300 nm.

In addition, the band gap energy of the multidimensional perovskite hybrid light emitting layer may be 1 eV to 5 eV.

(b) over-coating method

In addition, the step of forming the multi-dimensional perovskite hybrid light emitting layer 30 is

Preparing a perovskite bulk polycrystalline (1) precursor solution and a perovskite nanocrystalline particle solution;

Forming a perovskite bulk polycrystalline thin film by coating the perovskite bulk polycrystalline (1) precursor solution on a first electrode or a hole injection layer; And

And coating the perovskite nanocrystalline particle (2) solution on the formed perovskite bulk polycrystalline (1) thin film.

In the case of the perovskite nanocrystalline particles 2, the crystal is dispersed in an anti-solvent that does not dissolve, and is used to thin it, so that the previously formed perovskite bulk polycrystalline (1) coating on the thin film This is possible.

The steps of preparing the perovskite bulk polycrystalline (1) precursor solution and the perovskite nanocrystalline particle (2) solution are the same as described above, and detailed description thereof will be omitted.

Next, a perovskite bulk polycrystalline (1) precursor solution is coated on the hole injection layer and coated.

The difference between the overcoating method and the above-described dripping method is that the dripping method is performed by applying a solution of a low-dimensional perovskite nanocrystalline particle (2) before forming a high-dimensional perovskite bulk polycrystalline (1) thin film. One thin film is formed by coating, but the overcoating method forms a thin film of perovskite bulk polycrystalline (1), and then coats the thin film by applying a solution of perovskite nanocrystalline particles (2) on the thin film. To form.

At this time, the first electrode 20 or the hole injection layer in order to uniformly apply the perovskite bulk polycrystalline (1) precursor solution on the first electrode 20 or the hole injection layer 25 (25) can be rotated. Likewise, when the solution of the perovskite nanocrystalline particles 2 is applied, the coated body can be rotated to apply evenly.

The rotational speed is preferably 1000 to 8000 rpm, and if it is less than 1000 rpm, there is a problem in uniform film formation, and if it exceeds 8000 rpm, there is a problem in uniform crystal growth as the evaporation of the solvent becomes remarkably faster.

The coating may be made of spin coating, bar coating, nozzle printing, spray printing, slot die coating, gravure printing, inkjet printing, screen printing, electrohydrodynamic jet printing or electrospray.

In addition, after coating the nanocrystalline particles 2, a purification process for removing impurities from the nanocrystalline particle 2 solution may be additionally performed, and the purification process may be performed by applying a non-polar solvent.

In one embodiment of the present invention, while rotating at 3000 rpm for 20 seconds, the non-polar solvent was applied to remove impurities.

After coating, heat treatment may be performed to increase the density of the thin film.

The heat treatment can be performed at 80 ~ 120 ℃.

In one embodiment of the present invention, the prepared perovskite bulk polycrystalline (1) thin film and perovskite nanocrystalline particle (2) layer was heat treated at 90 ° C. for 10 minutes.

The multi-dimensional perovskite hybrid light-emitting layer manufactured by the over-coating method according to an embodiment of the present invention showed significantly improved photoluminescence intensity compared to a single-dimensional light-emitting layer made of only one-dimensional material (see FIG. 8), When a light emitting device was manufactured using perovskite bulk polycrystalline and nanocrystalline particles having different emission wavelength bands as an emission layer, electroluminescence was generated in both wavelength bands (see FIG. 9).

(c) polycrystalline vacuum deposition method

In addition, the step of forming the multi-dimensional perovskite hybrid light emitting layer 30 is

Preparing a solution of perovskite bulk polycrystalline (1) precursor and perovskite nanocrystalline particles (2);

Forming a perovskite nanocrystalline particle (2) layer by coating the perovskite nanocrystalline particle (2) solution on the first electrode (20) or the hole injection layer (25); And

It may include the step of vacuum depositing the perovskite bulk polycrystalline (1) precursor on the formed perovskite nanocrystalline particles (2) layer.

(d) Simultaneous deposition method

In addition, the step of forming the multi-dimensional perovskite hybrid light emitting layer 30 is

Perovskite bulk polycrystalline (1) precursor (precursor) and perovskite nanocrystalline particles (2) can be carried out by vapor deposition at the same time.

In the polycrystalline vacuum deposition method or the simultaneous deposition method, the deposition method is evaporation, thermal deposition, flash deposition, laser deposition, chemical vapor deposition deposition, atomic layer deposition, physical vapor deposition, physical-chemical co-evaporation deposition, sequential vapor deposition, solution process combination deposition (solution process-assisted thermal deposition) and spray deposition (Spray deposition).

An electron transport layer 35 may be additionally formed on the light emitting layer 30.

The material of the electron transport layer 35 is Alq ₃ (Tris (8-hydroxyquinolinato) aluminium), TAZ (3- (Biphenyl-4-yl) -5- (4-tert-butylphenyl) -4-phenyl-4H- 1,2,4-triazole), BAlq (Bis (8-hydroxy-2-methylquinoline)-(4-phenylphenoxy) aluminum), BeBq2 (bis (10-hydroxybenzo [h] quinolinato) -beryllium), BCP (Bathocuproine) , Bphen (Bathophenanthroline), TBPI (2,2 ', 2 "-(1,3,5-Benzinetriyl) -tris (1-phenyl-1-H-benzimidazole)), TmPyPB (1,3,5-Tri ( m-pyridin-3-ylphenyl) benzene), 3TPYMB (Tris (2,4,6-triMethyl-3- (pyridin-3-yl) phenyl) borane) or TpPyPB (1,3,5-tri (p-pyrid) -3-yl-phenyl) benzene Basic information).

The electron transport layer 35 is a vacuum deposition method, a spin coating method, a spray method, a dip coating method, a bar coating method, a nozzle printing method, a slot-die coating method, a gravure printing method, a cast method or a Langmuir-Blodjet film method (LB (Langmuir-Blodgett)) may be deposited on the light emitting layer 300 according to a randomly selected method from various known methods such as. At this time, the conditions and coating conditions at the time of deposition may vary depending on the target compound, the structure of the target layer, and thermal properties.

The electron transport layer 35 may have a thickness of about 10 nm to 100 nm. More specifically, it may be 20nm to 50nm.

An electron injection layer (not shown) may be additionally formed on the electron transport layer 35.

As the electron injection layer forming material, known electron injection materials LiF, NaCl, NaF, CsF, Li ₂ O, BaO, BaF ₂ , Cs ₂ CO ₃ or Liq (lithium quinolate) may be used.

The thickness of the electron injection layer may be about 0.1nm to 10nm. More specifically, it may be 0.5nm to 5nm.

In addition, the electron injection layer is Alq ₃ , TAZ, BAlq, BeBq ₂ , BCP, Bphen, TBPI, TmPyPB, 3TPYMB or TpPyPB, such as 1% to 50% of the content of the LiF, NaCl, CsF, Including metal derivatives such as NaF, Li ₂ O, BaO, and Cs ₂ CO ₃ , the electron transport layer material may be formed of a layer having a thickness of 1 nm to 100 nm doped with metals such as Li, Ca, Cs, and Mg. have.

Next, a second electrode 40 is formed on the light emitting layer 30 or the electron transport layer 35 or the electron injection layer.

For example, when the first electrode 20 is an anode, the second electrode 40 may be a cathode (electron injection electrode).

In this case, the second electrode 40 may use a material having a relatively low work function, a metal, an alloy, an electrically conductive compound, or a combination thereof. For example, the second electrode 400 is lithium (Li), magnesium (Mg), aluminum (Al), aluminum-lithium (Al-Li), calcium (Ca), magnesium-indium (Mg-In), Magnesium-silver (Mg-Ag), and the like. In addition, ITO or IZO can be used to obtain a front light emitting device.

The second electrode 40 may also be formed using a vacuum deposition method.

Hereinafter, exemplary embodiments of the present invention will be described in more detail with reference to the accompanying drawings in order to describe the present invention in more detail. Such, the present invention is not limited to the experimental examples described herein, but may be embodied in other forms.

Preparation Example 1 and Preparation Example 2 described below describe the preparation examples of the high-dimensional perovskite precursor solution and the low-dimensional perovskite nanocrystalline particle solution, respectively, and Preparation Examples 3 and 4 are multi-dimensional perovskite The manufacturing example of the hybrid light emitting layer is described.

<Production Example 1> Preparation of perovskite bulk polycrystalline precursor solution

The first solution was prepared by dissolving organic-inorganic hybrid perovskite in a polar solvent. At this time, dimethyl sulfoxide was used as a polar solvent, and CH ₃ NH ₃ PbBr ₃ was used as an organic-inorganic hybrid perovskite. The CH ₃ NH ₃ PbBr _{3 used} was a mixture of CH ₃ NH ₃ Br and PbBr ₂ in a ratio of 1.06: 1, and a mixture of a precursor and dimethyl sulfoxide in a ratio of 33 wt% was used.

<Production Example 2> Perovskite nanocrystalline particle solution preparation

The first solution was prepared by dissolving organic-inorganic hybrid perovskite in a polar solvent. At this time, dimethylformamide was used as a polar solvent, and CH ₃ NH ₃ PbBr ₃ was used as an organic-inorganic hybrid perovskite. At this time, the CH ₃ NH ₃ PbBr ₃ was used by mixing CH ₃ NH ₃ Br and PbBr ₂ at a ratio of 1: 1 by adding 0.4 mml each.

Then, a second solution was prepared in which an amine ligand and a carboxylic acid surfactant were dissolved in a non-polar solvent. At this time, hexane (Hexane) was used as the non-polar solvent, octylamine was used as the amine ligand surfactant, and oleic acid was used as the carboxylic acid surfactant.

Then, the first solution was slowly added dropwise to the strongly stirred second solution to form organic-inorganic hybrid perovskite nanocrystalline particles.

Thereafter, the nanocrystalline particles and the solvent were separated using centrifugation, and the supernatant (solvent) was decanted, and then redispersed with fresh toluene.

In the subsequent procedure, a redispersed perovskite nanocrystalline particle solution was used.

<Production Example 3> Multi-dimensional perovskite hybrid light emitting layer production (dripping method)

After applying the perovskite bulk polycrystalline precursor solution prepared in Preparation Example 1 onto the glass substrate, the glass substrate was spin coated while rotating at a speed of 3000 rpm. After applying the perovskite bulk polycrystalline precursor solution, 25 seconds later, the perovskite nanocrystalline particle solution prepared in Preparation Example 2 was injected and coated together to prepare a multidimensional perovskite hybrid thin film.

The prepared thin film was heat treated at 90 ° C for 10 minutes.

The prepared thin film was observed by a scanning electron microscope and shown in FIG. 5.

As shown in FIG. 5, the hybrid thin film coated with the perovskite bulk polycrystalline precursor solution and the perovskite nanocrystalline particle solution, drips only toluene solvent instead of the perovskite nanocrystalline particle solution. Compared to the one, the perovskite nanocrystalline particles acted as crystallization seeds, providing many crystallization sites, thereby inducing the granular structure of the thin film.

<Production Example 4> Preparation of multi-dimensional perovskite hybrid light emitting layer (overcoating method)

After applying the perovskite bulk polycrystalline precursor solution prepared in Preparation Example 1 on the organic substrate, the glass substrate was spin coated while rotating at a speed of 3000 rpm.

The prepared thin film was heat treated at 90 ° C for 10 minutes.

The prepared thin film was observed by a scanning electron microscope and shown in FIG. 6.

Next, after applying the perovskite nanocrystalline particle solution prepared in Preparation Example 2 on the perovskite bulk polycrystalline thin film, the substrate was spin coated while rotating at a speed of 3000 rpm.

The prepared thin film was heat treated at 90 ° C for 10 minutes.

The prepared thin film was observed by a scanning electron microscope and shown in FIG. 6.

As shown in Fig. 6, a hybrid thin film formed by overcoating a thin film of perovskite nanocrystalline particles on a perovskite bulk polycrystalline thin film has a perovskite nanocrystalline particle having a perovskite bulk polycrystalline thin film. It can be seen that the nanoparticle layer is formed on the thin film without destruction.

< Manufacturing example  5> Multidimensional Perovskite hybrid Emitting layer  Manufacturing (Polycrystalline deposition method)

After the perovskite nanocrystalline particle solution prepared in Preparation Example 2 was applied onto the perovskite bulk polycrystalline thin film, the substrate was spin coated while rotating at a speed of 3000 rpm.

The prepared thin film was heat treated at 90 ° C for 10 minutes.

Next, in a high vacuum (1 × 10 ^-7 Torr) state thermal evaporator, MABr and PbBr ₂ are co-deposited by thermal deposition on the perovskite nanocrystalline particle layer to form a perovskite bulk polycrystalline material. A layer was formed.

< Manufacturing example  6> Multidimensional Perovskite hybrid Emitting layer  Manufacturing (simultaneous deposition method)

The perovskite bulk polycrystalline precursor solution prepared in Preparation Example 1 and the perovskite nanocrystalline particle solution prepared in Preparation Example 2 were coated on the substrate heated to 75 ° C. using two nozzles to perform coating through simultaneous spraying. Proceeded. During spray deposition, the nozzle height was 10 cm, and the atomizing gas pressures of the perovskite bulk polycrystalline solution and perovskite nanocrystalline particle solution were 2.5 psi and 1.5 psi, respectively, and the solution injection rates were 3.0 ml / min and 2.0, respectively. It was set to ml / min.

The prepared thin film was heat treated at 100 ° C for 50 minutes.

< Manufacturing example  7> Light-emitting diode manufacturing ( Dripping  method)

First, an ITO substrate (a glass substrate coated with an ITO anode) is prepared, and then spin coated with a conductive material PEDOT: PSS (AI4083 from Heraeus) on the ITO anode, followed by heat treatment at 150 ° C for 30 minutes to inject 40 nm thick holes A layer was formed.

The perovskite bulk polycrystalline precursor solution prepared in Preparation Example 1 was applied onto the hole injection layer and spin-coated while rotating at a speed of 3000 rpm. After applying the perovskite bulk polycrystalline precursor solution, 25 seconds later, the perovskite nanocrystalline particle solution prepared in Preparation Example 2 was injected and coated together, followed by heat treatment at 90 ° C. for 10 minutes to multidimensional perovskite. To form a hybrid light emitting layer.

After this, a 50 nm thick 1,3,5-Tris (1-phenyl-1H-benzimidazol-2-yl) benzene (TPBI) on a multi-dimensional perovskite hybrid light-emitting layer under a high vacuum of 1 × 10 ^-7 Torr or less To form an electron transport layer, a 1 nm thick LiF was deposited thereon to form an electron injection layer, and a 100 nm thick aluminum was deposited thereon to form a negative electrode to produce a multi-dimensional perovskite hybrid light emitting diode.

< Manufacturing example  8> Light-emitting diode manufacturing (overcoating method)

First, prepare an ITO substrate (glass substrate coated with an ITO anode), spin coat the conductive material PEDOT: PSS (AI4083 from Heraeus) on the ITO anode, and heat-treat at 150 ° C for 30 minutes to inject 40 nm thick holes. A layer was formed.

Next, the perovskite bulk polycrystalline precursor solution prepared in Preparation Example 1 was applied onto the hole injection layer and spin-coated while rotating at a speed of 3000 rpm. The prepared thin film was heat treated at 90 ° C for 10 minutes. Then, while rotating at a speed of 3000 rpm, the perovskite nanocrystalline solution prepared in Preparation Example 2 was spin coated on the perovskite bulk polycrystalline thin film, and hexane was used to remove impurities from the nanocrystalline particles. After coating and heat treatment at 90 ° C. for 10 minutes, a multi-dimensional perovskite hybrid light emitting layer was formed.

After this, a 50 nm thick 1,3,5-Tris (1-phenyl-1H-benzimidazol-2-yl) benzene (TPBI) on a multi-dimensional perovskite hybrid light-emitting layer under a high vacuum of 1 × 10 ^-7 Torr or less To form an electron transport layer, deposit 1 nm-thick LiF on it to form an electron injection layer, and deposit 100 nm-thick aluminum on it to form a negative electrode to produce a multi-dimensional perovskite hybrid light-emitting diode.

< Manufacturing example  9> Light-emitting diode production (polycrystalline deposition method)

First, prepare an ITO substrate (glass substrate coated with an ITO anode), spin coat the conductive material PEDOT: PSS (AI4083 from Heraeus) on the ITO anode, and heat-treat at 150 ° C for 30 minutes to inject 40 nm thick holes. A layer was formed.

Next, the perovskite nanocrystalline particle solution prepared in Preparation Example 2 was spin coated on the perovskite bulk polycrystalline thin film, heat-treated at 90 ° C. for 10 minutes, and then subjected to high vacuum (1 × 10-7 Torr). Multi-dimensional perovskite hybrid light-emitting layer by forming a perovskite bulk polycrystalline layer by co-depositing MABr and PbBr ₂ through thermal deposition on the perovskite nanocrystalline particle layer in a thermal evaporator in a state) Formed.

After this, a 50 nm thick 1,3,5-Tris (1-phenyl-1H-benzimidazol-2-yl) benzene (TPBI) on a multi-dimensional perovskite hybrid light-emitting layer under a high vacuum of 1 × 10 ^-7 Torr or less To form an electron transport layer, a 1 nm thick LiF was deposited thereon to form an electron injection layer, and a 100 nm thick aluminum was deposited thereon to form a negative electrode to produce a multi-dimensional perovskite hybrid light emitting diode.

< Manufacturing example  10> Light emitting diode manufacturing (simultaneous deposition method)

First, an ITO substrate (a glass substrate coated with an ITO anode) is prepared, then spin-coated a conductive material PEDOT: PSS (AI4083 from Heraeus) on the ITO anode, followed by heat treatment at 150 ° C for 30 minutes to inject 40 nm thick holes A layer was formed.

Next, the perovskite bulk polycrystalline precursor solution prepared in Preparation Example 1 and the perovskite nanocrystalline particle solution prepared in Preparation Example 2 were simultaneously sprayed using two nozzles on a substrate heated to 75 ° C. The coating proceeded through. During spray deposition, the nozzle height was 10 cm, and the atomizing gas pressures of the perovskite bulk polycrystalline solution and perovskite nanocrystalline particle solution were 2.5 psi and 1.5 psi, respectively, and the solution injection rates were 3.0 ml / min and 2.0, respectively. It was set to ml / min.

The prepared thin film was heat treated at 100 ° C for 50 minutes.

After this, a 50 nm thick 1,3,5-Tris (1-phenyl-1H-benzimidazol-2-yl) benzene (TPBI) on a multi-dimensional perovskite hybrid light-emitting layer under a high vacuum of 1 × 10 ^-7 Torr or less To form an electron transport layer, a 1 nm thick LiF was deposited thereon to form an electron injection layer, and a 100 nm thick aluminum was deposited thereon to form a negative electrode to produce a multi-dimensional perovskite hybrid light emitting diode.

<Comparative Example>

The perovskite bulk polycrystalline precursor solution prepared in Preparation Example 1 was applied onto the organic substrate and spin coated while rotating the glass substrate at a speed of 3000 rpm.

The prepared thin film was heat treated at 90 ° C for 10 minutes.

<Experimental Example 1> Photoluminescence (PL) intensity measurement

In the present invention, in order to investigate the effect of introducing perovskite nanocrystalline particles on perovskite bulk polycrystalline on photoluminescence properties, the following experiment was performed.

The photoluminescence properties of the light-emitting layers prepared in Preparation Examples 3 and 4 were measured using a spectrofluorometer, and the results are shown in FIGS. 7 and 8, respectively, compared to the method of Comparative Example.

7 is a graph showing the light emission intensity of a multi-dimensional perovskite hybrid light-emitting layer prepared using the dripping method of Preparation Example 3 of the present invention and a perovskite bulk polycrystalline light-emitting layer composed of a single dimension of a comparative example.

As shown in FIG. 7, the perovskite bulk polycrystalline thin film composed of a single dimension of the comparative example exhibited a light emission intensity of 125 au in a wavelength range of 525 to 550 nm, but was prepared according to the dripping method of the present invention. A multi-dimensional perovskite hybrid thin film in which perovskite bulk polycrystalline and perovskite nanocrystals coexist exhibits a light emission intensity of about 800 to 900 au in the same wavelength range, thereby significantly increasing the light emission intensity of about 6 times or more. You can see that it improves.

8 is a graph showing the photoluminescence intensity of a multi-dimensional perovskite hybrid light-emitting layer manufactured using the overcoat method of Preparation Example 4 of the present invention and a single-dimensional perovskite bulk polycrystalline light-emitting layer of a comparative example.

As shown in FIG. 8, a multi-dimensional perovskite hybrid thin film in which perovskite bulk polycrystals and perovskite nanocrystals co-exist according to the overcoat method of the present invention coexist at about 250 au in the same wavelength region By indicating the photoluminescence intensity, the photoluminescence intensity was increased by about 2 times compared to the high-dimensional perovskite bulk thin film 125 au composed of a single dimension.

9 is a multi-dimensional perovskite hybrid light-emitting layer prepared according to Preparation Example 4 of the present invention, a perovskite bulk polycrystalline light-emitting layer composed of a single dimension in 3D, or a perovskite nanoscale composed of a single dimension in 0D It is a graph showing the electroluminescence spectrum of the crystal particle emitting layer.

As shown in FIG. 9, in the case of a multi-dimensional perovskite hybrid thin film in which perovskite bulk polycrystalline and perovskite nanocrystalline particles coexist according to the overcoat method of the present invention, perovskite bulk It has been shown that multi-color emission is possible by emitting light in both the electroluminescent wavelength band (~ 540 nm) and the perovskite nanocrystalline particle electroluminescent wavelength band (~ 525 nm).

Accordingly, the multi-dimensional perovskite hybrid thin film in which the perovskite bulk polycrystalline and perovskite nanocrystalline particles coexist according to the present invention emits light at a higher light emission intensity and a complex wavelength, thereby limiting the conventional light-emitting diodes. Can overcome.

On the other hand, the embodiments of the present invention disclosed in the specification and drawings are merely presented as specific examples to aid understanding, and are not intended to limit the scope of the present invention. It is obvious to those skilled in the art to which the present invention pertains that other modified examples based on the technical idea of the present invention can be implemented in addition to the embodiments disclosed herein.

1: perovskite bulk polycrystalline
2: Perovskite nanocrystalline particles
10: substrate
20: first electrode
25: hole injection layer
30: light emitting layer
35: electron transport layer
40: second electrode

Claims (17)

Board;
A first electrode positioned on the substrate;
A light emitting layer positioned on the first electrode; And
It includes a second electrode located on the light emitting layer,
The light emitting layer is a perovskite bulk polycrystalline thin film (bulk polycrystal) and a perovskite light emitting diode, characterized in that the multi-dimensional perovskite hybrid light emitting layer composed of a combination of perovskite nanocrystalline particle layer. According to claim 1,
The light emitting diode includes a hole injection layer between the first electrode and the light emitting layer, and a perovskite light emitting diode comprising an electron transport layer between the light emitting layer and the second electrode. According to claim 1,
The multi-dimensional perovskite hybrid light-emitting layer is a perovskite bulk polycrystalline thin film (bulk polycrystal) and perovskite nanocrystalline particle layer is sequentially deposited, or co-deposited perovskite light emitting diode, characterized in that formed. According to claim 1,
The perovskite bulk polycrystalline thin film has an ABX ₃ structure as a three-dimensional structure, or ABX ₃ , A ₂ BX ₄ , ABX ₄ or A _n-1 B _n X _{3n + 1} as a two-dimensional structure (n is between 2 to 6). In this case, A is an amidinium-based organic material, an organic ammonium material, an organic phosphonium ion, an alkali metal or a transition metal, wherein B is a transition metal, rare earth metal, alkaline earth metal, organic substance, Perovskite light emitting diode, characterized in that the inorganic material, ammonium or a derivative thereof, or a combination thereof, and X is a halogen element. According to claim 4,
The A is formamidinium, acetamidinium, guamidinium, C _x H _{2x + 1} (CNH ₃ ), (CH ₃ NH ₃ ) _n , ((C _x H _{2x + 1} ) _n NH ₃ ) _n (CH ₃ NH ₃ ) _n , R (NH ₂ ) ₂ (where R = alkyl), (C _n H _{2n + 1} NH ₃ ) _n , (CF ₃ NH ₃ ), (CF ₃ NH ₃ ) _n , ( (C _x F _{2x + 1} ) _n NH ₃ ) _n (CF ₃ NH ₃ ) _n , ((C _x F _{2x + 1} ) _n NH ₃ ) _n , (C _n F _{2n + 1} NH ₃ ) _n (where n and x are integers from 1 to 100), Na, K, Rb, Cs, Fr, TI or combinations or derivatives thereof,
The B is Pb, Mn, Cu, Ga, Ge, In, Al, Sb, Bi, Po, Sn, Eu, Yb, Ni, Co, Fe, Cr, Pd, Cd, Ca, Sr, organic ammonium, inorganic ammonium , An organic cation or a combination or derivative thereof,
The X is Cl, Br, I or a perovskite light emitting diode, characterized in that a combination thereof. Forming a first electrode on the substrate;
Forming a multidimensional perovskite hybrid light emitting layer composed of a combination of perovskite bulk polycrystal and perovskite nanocrystalline particle layer on the first electrode; And
A method of manufacturing a perovskite light emitting diode comprising forming a second electrode on the light emitting layer. Forming a first electrode on the substrate;
Forming a hole injection layer on the first electrode;
Forming a multidimensional perovskite hybrid light emitting layer composed of a combination of a perovskite bulk polycrystalline thin film and a perovskite nanocrystalline particle layer on the hole injection layer;
Forming an electron transport layer on the light emitting layer; And
A method of manufacturing a perovskite light emitting diode comprising forming a second electrode on the electron transport layer. The method of claim 6 or 7,
The step of forming the multi-dimensional perovskite hybrid light emitting layer is
Preparing a perovskite bulk polycrystalline precursor solution and a perovskite nanocrystalline particle solution;
Applying the perovskite bulk polycrystalline precursor solution on a first electrode or a hole injection layer; And
Before the coating of the perovskite bulk polycrystalline precursor solution is completed, the perovskite nanocrystalline particle solution is dropped to remove the perovskite bulk polycrystalline and perovskite nanocrystalline particles. Method of manufacturing a perovskite light-emitting diode comprising a step of coating together. The method of claim 8,
Method for producing a perovskite light emitting diode, characterized in that the time of injecting the nanocrystalline particle solution is performed within 1 second to 200 seconds after application of the perovskite bulk polycrystalline precursor solution. The method of claim 6 or 7,
The step of forming the multi-dimensional perovskite hybrid light emitting layer is
Preparing a perovskite bulk polycrystalline precursor solution and a perovskite nanocrystalline particle solution;
Forming a perovskite bulk polycrystalline thin film by coating the perovskite bulk polycrystalline precursor solution on a first electrode or a hole injection layer; And
A method of manufacturing a perovskite light emitting diode comprising coating the perovskite nanocrystalline particle solution on a formed perovskite bulk polycrystalline thin film. The method of claim 6 or 7,
The step of forming the multi-dimensional perovskite hybrid light emitting layer is
Preparing a perovskite bulk polycrystalline precursor and a perovskite nanocrystalline particle solution;
Forming a perovskite nanocrystalline particle layer by coating the perovskite nanocrystalline particle solution on a first electrode or a hole injection layer; And
A method of manufacturing a perovskite light emitting diode, comprising vacuum depositing the perovskite bulk polycrystalline precursor on the formed perovskite nanocrystalline particle layer. The method of claim 6 or 7,
The step of forming the multi-dimensional perovskite hybrid light emitting layer is performed by simultaneously vacuum-depositing perovskite bulk polycrystalline precursor and perovskite nanocrystalline particles. Method of manufacturing. The method of claim 8,
The perovskite nanocrystalline particle solution
Preparing a first solution in which a metal halide perovskite is dissolved in a polar solvent and a second solution in which a surfactant is dissolved in a non-polar solvent or a polar solvent; And
A method of manufacturing a perovskite light emitting diode, characterized in that it is prepared by a method comprising mixing the first solution with the second solution to form metal halide perovskite nanocrystalline particles. The method of claim 13,
The surfactant is a method for producing a perovskite light-emitting diode, characterized in that it comprises an amine ligand, an organic acid, an inorganic ligand or an organic ammonium ligand. The method of claim 14,
The amine ligand is N, N-diisopropylethylamine, ethylene diamine, hexamethylenetetraamine, methylamine, propyl amine, butylamine, hexylamine, heptylamine, octylamine, norylamine, decylamine, undecylamine, Dodecylamine, hexadecylamine, octadecylamine, oleylamine, benzylamine, N, N, N, N-tetramethyleneethylenediamine, triethylamine, diethanolamine, 2,2- (ethylenedioxyl) bis -(Ethylamine), 2-methyl-1,5-pentanediamine, 3-methoxytriphenyl-amine, 1,4-phenylenediamine, N, N, N, N-pentamethyl diethylenetriamine, tri Selected from ethylenetetramine, rhodamine, diethylamine and ethyllindiamine,
The organic acid is 4,4'-azobis (4-cyanopaleric acid) (4,4'-Azobis (4-cyanovaleric acid)), acetic acid (Acetic acid), 5-myosalicyclic acid ( 5-Aminosalicylic acid, Acrylic acid, L-Aspentic acid, 6-Bromohexanoic acid, Promoacetic acid, Dichloro Dichloro acetic acid, ethylenediaminetetraacetic acid, isobutyric acid, itaconic acid, maleic acid, r-maleimidobutyl R-Maleimidobutyric acid, L-Malic acid, 4-Nitrobenzoic acid, 1-Pyrenecarboxylic acid, Hexanoic Hexanoic acid, octanoic acid, decanoic acid, undecanoic acid un decanoic acid, dodecanoic acid, hexadecenoic acid octadecanoic acid, oleic acid, n-hexylphosphonic acid, n-octyl Phosphonic acid, n-decylphosphonic acid, n-dodecylphosphonic acid, n-tetradecylphosphonic acid, n-hexadecylphosphonic acid, n-octadecylphosphonic acid, benzylphosphonic acid and benzhai Drill phosphonic acid, n-aminobenzoic acid,
The organic ammonium ligand is a ligand having an alkyl-X structure, and the alkyl is an acyl alkyl (C _n H _{2n +1} ); Polyhydric alcohols including primary alcohols, secondary alcohols, and tertiary alcohols (C _n H _{2n + 1} OH); Alkylamines including hexadecyl amine, 9-octadecenylamine, and 1-amino-9-octadacene (C ₁₉ H ₃₇ N); Method for producing a perovskite light-emitting diode, characterized in that X is Cl, Br or I, selected from the group consisting of p-substituted aniline, phenyl ammonium and fluorine ammonium. The method of claim 13,
Mixing the first solution with the second solution is characterized by using a method selected from spray spraying, dripping finely drop by drop, and dropping at a time. Method of manufacturing perovskite light emitting diodes. The method of claim 12,
The deposition is evaporation, thermal deposition, flash deposition, laser deposition, chemical vapor deposition, atomic layer deposition, physical vapor Deposition (physical vapor deposition), physical-chemical co-evaporation deposition, sequential vapor deposition, solution process-assisted thermal deposition and spray deposition ) Is a method of manufacturing a perovskite light emitting diode, characterized in that is performed by a method selected from the group consisting of.

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