KR20210077257A - Process of manufacturing light emitting film having inorganic luminescent particle, process of light emitting device and inorganic light emitting diode having inorganic luminescnent particle - Google Patents

Abstract

The present invention relates to a method for manufacturing a thin film by heat-treating a thin film made of inorganic light-emitting particles in a high-vacuum condition and performing hydrothermal treatment, and to a method for manufacturing a light emitting diode and a light emitting device including the thin film. By the two-step heat treatment according to the present invention, the inorganic light-emitting particles are stabilized by removing surface defects of the inorganic light-emitting particles, and the luminous efficiency of the inorganic light-emitting particles is improved. The thin film with improved luminous efficiency may be applied to a light emitting film interposed between a liquid crystal panel and a backlight unit in a liquid crystal display device or together with other light emitting sheets in the backlight unit, to a color conversion layer disposed adjacent to an array panel, and to a light emitting material layer constituting the inorganic light emitting diode.

Description

Method of manufacturing a light emitting film containing inorganic light emitting particles, a light emitting device and a method of manufacturing an inorganic light emitting diode

The present invention relates to a method for manufacturing a light emitting film and a light emitting device, and more particularly, to a method for manufacturing a light emitting film having improved luminous efficiency of inorganic light emitting particles, and manufacturing a light emitting device and an inorganic light emitting diode comprising inorganic light emitting particles it's about how to

With the development of information communication technology and electronic engineering technology, various flat panel display devices replacing the conventional cathode ray tube display (CRT) are being studied. Among flat panel displays, liquid crystal display (LCD) devices that can realize thinner and lighter weight compared to CRTs, organic light emitting diodes (OLEDs), and quantum dot light emitting diodes (OLEDs) are introduced. A quantum dot light emitting display device incorporating a Dot Light Emitting Diode (QLED or QD-LED) is attracting attention.

The organic light emitting display device and the quantum dot light emitting display device each include an organic light emitting diode or a quantum dot light emitting diode, which is a self-light emitting device, as essential components. Compared to a liquid crystal display, which is a non-light emitting device that requires a backlight unit, the organic light emitting display device and the quantum dot light emitting display device can be further reduced in thickness and weight. In addition, organic light emitting diodes and quantum dot light emitting diodes are advantageous in terms of power consumption compared to liquid crystal display panels, and thus have advantages of low-voltage driving and fast response speed. In addition, since the organic light emitting diode and the quantum dot light emitting diode have a simple manufacturing process, there is an advantage in that the production cost can be greatly reduced compared to the conventional liquid crystal display device.

An organic light emitting display device or a quantum dot display device forms a red light emitting layer, a green light emitting layer, and a blue light emitting layer for each red (Red, R), green (Green, G), and blue (Blue, B) pixel area to form a red (Red), green ( By emitting green and blue light, a full-color image is realized. Recently, an organic light emitting diode or quantum dot display having a red/green/blue/white structure in which a light emitting diode emitting white light is formed over the entire pixel area and using a color filter or a color conversion layer is mainly used.

However, quantum dots or quantum rods, which are inorganic light emitting particles, are vulnerable to oxygen or moisture and have poor heat resistance. Therefore, when synthesizing inorganic light emitting particles or manufacturing a light emitting display device containing inorganic light emitting particles, the inorganic light emitting particles exposed to high temperature processes and external air or moisture deteriorate, so that the luminous efficiency and luminous lifespan of the light emitting display device are reduced. is lowered

An object of the present invention is a method for manufacturing a light emitting film capable of improving the luminous efficiency of inorganic light emitting particles, a method for manufacturing an inorganic light emitting diode comprising a light emitting material layer made of inorganic light emitting particles with improved light emitting efficiency, and inorganic light emitting with improved luminous efficiency An object of the present invention is to provide a method for manufacturing a light emitting device having a color conversion layer made of particles.

In one aspect, the present invention comprises the steps of preparing a light emitting film made of inorganic light emitting particles; loading the light emitting film into a chamber, and performing thermal annealing in a vacuum atmosphere and a temperature of 180 to 230°C; and performing hydro thermal annealing in the chamber in which the heat-treated light emitting film is loaded.

In another aspect, the present invention comprises the steps of preparing an array panel; disposing a color conversion layer made of inorganic light emitting particles on the array panel; loading the array panel on which the color conversion layer is disposed into a chamber, and performing heat treatment in a vacuum atmosphere and a temperature of 180 to 230°C; and performing hydrothermal treatment in the chamber in which the array panel on which the heat-treated color conversion layer is disposed is loaded.

In another aspect, the present invention comprises the steps of forming a first charge transfer layer on the first electrode; forming a light emitting material layer including inorganic light emitting particles on the first charge transfer layer; loading the thin film on which the light emitting material layer is formed into a chamber, and performing heat treatment in a vacuum atmosphere and a temperature of 180 to 230°C; and performing hydrothermal treatment in the chamber in which the heat-treated thin film is loaded.

The present invention provides a high-vacuum thin film, such as a light emitting film, a color conversion layer, and/or a light emitting material layer of an inorganic light emitting diode, comprising inorganic light emitting particles that are degraded by reaction with oxygen or moisture outside in a high temperature state and/or We propose a method for improving the luminous efficiency of inorganic light-emitting materials by first heat-treating under the conditions and secondly performing hydrothermal treatment.

By introducing the process of the present invention, it is possible to minimize the separation of the organic ligand from the inorganic light-emitting particles, minimize surface defects such as vacant lattice dots on the surface of the inorganic light-emitting particles, remove the oxide film, and organic light-emitting particles on the surface of the inorganic light-emitting particles By strongly binding the ligand, the inorganic luminescent particles are stabilized. Accordingly, excitons are stably formed by recombination of charges in the inorganic light emitting material, and the luminous efficiency of the inorganic light emitting particles can be improved. By introducing the process of the present invention, it is possible to implement a light emitting film, an inorganic light emitting diode and a light emitting device with improved luminous efficiency.

1 is a schematic diagram schematically showing a process in which an inorganic light emitting particle is degraded as an organic ligand on the surface of an inorganic light emitting particle is separated and an oxide film is formed by reacting with external oxygen under a high temperature condition.
2A and 2B are schematic diagrams schematically showing equipment including a vacuum chamber that can be applied to a process for producing inorganic light-emitting particles with improved luminous efficiency according to the present invention, respectively. Fig. 2a schematically shows the high-vacuum heat treatment step, and Fig. 2b schematically shows the hydrothermal treatment step.
3 is a schematic diagram schematically showing a process in which deteriorated inorganic light-emitting particles are converted into inorganic light-emitting particles having improved luminous efficiency through the process of the present invention.
4 is a cross-sectional view schematically illustrating a light emitting display device to which a micro LED is introduced as an example of a light emitting device including a color conversion layer having improved luminous efficiency according to an exemplary embodiment of the present invention. In order to avoid overlapping portions, the thin film transistor is shown in detail only in the red sub-pixel region, and the configuration of the thin film transistor in the remaining sub-pixel region is omitted.
5A to 5D are cross-sectional views schematically showing a light emitting device including a color conversion layer having improved luminous efficiency according to an exemplary embodiment of the present invention according to respective steps.
6 is a cross-sectional view schematically illustrating a light emitting display device to which a light emitting diode is introduced as an example of a light emitting device including a color conversion layer having improved light emitting efficiency according to another exemplary embodiment of the present invention. In order to avoid overlapping portions, the thin film transistor is shown in detail only in the red sub-pixel region, and the configuration of the thin film transistor in the remaining sub-pixel region is omitted.
7A to 7C are cross-sectional views schematically showing a light emitting device including a color conversion layer having improved luminous efficiency according to another exemplary embodiment of the present invention according to respective steps.
8 is a cross-sectional view schematically illustrating an inorganic light emitting diode including a light emitting material layer having improved light emitting efficiency according to another exemplary embodiment of the present invention.
9A to 9D are cross-sectional views schematically showing an inorganic light emitting diode including a light emitting material layer having improved light emitting efficiency according to another exemplary embodiment of the present invention according to each step.
10A to 10D are electron microscope (TEM) pictures showing the surface morphology of a light emitting film in each process according to an embodiment of the present invention. 10A shows the light emitting film obtained before the curing process, FIG. 10B immediately after the curing process, FIG. 10C after high-vacuum heat treatment, and FIG. 10D after hydrothermal treatment.
11a and 11b are emission gas analysis-mass spectrometry (EGA-MS) for determining the binding force of the organic ligand attached to the surface of the inorganic light emitting particle constituting the light emitting film according to an embodiment of the present invention; ) is a graph showing the results. FIG. 11A is an analysis result of a light emitting film before the curing process, and FIG. 11B is a high-vacuum heat treatment and hydrothermal treatment.
12a and 12b are gas chromatography-mass spectrometry (GC-MS) for examining the binding force of the organic ligand attached to the surface of the inorganic light-emitting particle constituting the light-emitting film according to an embodiment of the present invention; This is a graph showing the results. FIG. 12A is a result of analyzing the light emitting film before the curing process, and FIG. 12B is the high-vacuum heat treatment and hydrothermal treatment.

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

A light emitting film containing inorganic light emitting particles such as quantum dots (QD) and quantum rods (QR) can be formed through a solution process such as an inkjet printing process as well as a photo resist (PR) process. can For example, the heat-curable type ink composition includes inorganic light-emitting particles, a polymer, a high refractive index material, and a solvent, and the inorganic light-emitting particles are typically included in the ink composition in a proportion of about 30% by weight. The thickness of the heat-curable film including the inorganic light emitting particles is usually 6 μm or more, and there is a problem in that the luminous efficiency of the inorganic light emitting particles is lowered by the firing process applying heat, which will be described.

1 is a schematic diagram schematically showing a process in which an inorganic light emitting particle is degraded as an organic ligand on the surface of an inorganic light emitting particle is separated and an oxide film is formed by reacting with external oxygen under a high temperature condition. The inorganic light emitting particles 100 may be formed of nano inorganic light emitting particles such as quantum dots (QDs) or quantum rods (QRs). Quantum dots or quantum rods are nano-inorganic particles that emit light as electrons in an unstable state descend from the conduction band energy level to the valence band energy level.

These nano-inorganic light-emitting particles 100 have a very high extinction coefficient and also have excellent quantum yield among inorganic particles, thereby generating strong fluorescence. In addition, since the emission wavelength is changed according to the size of the inorganic light emitting nano particles 100, by adjusting the size of the inorganic light emitting nano particles 100, light in the entire range of visible light can be obtained, so that various colors can be realized.

In one exemplary embodiment, the inorganic light emitting particles 100 such as quantum dots or quantum rods may have a single structure. In another exemplary embodiment, the inorganic light emitting particles 100 such as quantum dots or quantum rods may have a heterogeneous structure of a core 110 / shell 120, bonded to the surface of the shell 120, or A plurality of free organic ligands 130 may be included. In this case, the shell 120 may be formed of one shell or a plurality of shells (multi shells).

The type of reactive precursor that can be synthesized into the core 110 and/or the shell 120 , the injection rate of the reactive precursor for synthesizing the core 110 and/or the shell 120 , the reaction temperature, and the surface of the shell 120 . The growth degree and crystal structure of the nano-inorganic light-emitting particles 100 may be adjusted according to the type of the organic ligand 130 connected to the . As the energy band gap of the inorganic light emitting nano particles 100 is adjusted, light emission of various wavelength bands may be induced.

For example, the inorganic light emitting particles 100 such as quantum dots or quantum rods are type-° cores in which the energy bandgap of the core 110 is surrounded by the energy bandgap of the shell 120 . It can have a /shell structure. When the inorganic light emitting particle 300 has a type-I core/shell structure, electrons and holes move toward the core 110 and recombination of electrons and holes occurs in the core 110 to emit energy as light. Therefore, it is possible to adjust the emission wavelength of the inorganic light emitting particle 100 according to the thickness of the core 110 .

In another exemplary embodiment, the inorganic light emitting particles 100 such as quantum dots or quantum rods exist in which the band gap energy of the core 110 and the band gap energy of the shell 120 are staggered, so that electrons and holes are separated from the core. It may have a type II core/shell structure, which is a light emitting particle moving in opposite directions among the and the shell. In the case of the type II core/shell structure, the emission wavelength of the inorganic light emitting particles 100 may be adjusted according to the thickness of the shell 120 and the position of the band gap.

In another exemplary embodiment, the inorganic light-emitting particles 100 such as quantum dots or quantum rods are reverse-type-I (reversed type-I), which are light-emitting particles having a structure in which the energy band gap of the core 110 is larger than that of the shell 120. It may have a reverse type-I) core/shell structure. In the case of the reverse type-I core/shell structure, the emission wavelength of the inorganic light emitting particles 100 may be adjusted according to the thickness of the shell 320 .

For example, when the inorganic light-emitting particles 100 such as quantum dots or quantum rods form a type-I core/shell structure, the core 110 is a portion in which light is emitted substantially, and inorganic light is emitted according to the size of the core 110 . The emission wavelength of the particle 100 is determined. In order to receive the quantum confine effect, the core must have a size smaller than the exciton Bohr radius according to each material, and must have an optical band gap at the corresponding size.

The shell 120 constituting the inorganic light emitting particles 100 such as quantum dots or quantum rods promotes the quantum confinement effect of the core 110 and determines the stability of the inorganic light emitting particles 100 . Atoms exposed on the surface of the inorganic light emitting particle 100, such as colloidal quantum dots or quantum rods of a single structure, have electron states (lone pair electrons) that do not participate in chemical bonding, unlike internal atoms. Since the energy level of these surface atoms is located between the conduction band edge and the valence band edge of the inorganic light emitting particle 100 and can trap charges, in the inorganic light emitting particle 100 A surface defect may be caused. Due to the non-radiative recombination process of excitons due to surface defects, the luminous efficiency of the inorganic light emitting particles 100 may decrease, and the captured charges react with external oxygen and compounds to react with the inorganic light emitting particles. The chemical composition of (100) may be changed, or the electrical/optical properties of the inorganic light emitting particles 100 may be permanently lost.

In order for the shell 120 to be efficiently formed on the surface of the core 110 , the lattice constant of the material constituting the shell 120 should be similar to the lattice constant of the material constituting the core 110 . do. By enclosing the surface of the core 110 with the shell 120, oxidation of the core 110 is prevented to improve the chemical stability of the inorganic light emitting particle 100, and the core 110 caused by external factors such as water or oxygen. ) to prevent photodegeneration. In addition, it is possible to minimize the loss of excitons due to charge trapping on the surface of the core 110 and prevent energy loss due to molecular vibration, thereby improving the quantum efficiency of the inorganic light emitting particles 100 .

In one exemplary embodiment, the core 110 and the shell 120 may be semiconductor nanocrystals or metal oxide nanocrystals having a quantum confinement effect. For example, the semiconductor nanocrystal capable of forming the core 110 and/or the shell 120 may include a group II-VI compound semiconductor nanocrystal in the periodic table, a group III-V compound semiconductor nanocrystal in the periodic table, and a group IV-VI compound in the periodic table. It may be selected from the group consisting of semiconductor nanocrystals, group I-III-VI compound semiconductor nanocrystals of the periodic table, and combinations thereof.

Specifically, the group II-VI compound semiconductor nanocrystals of the periodic table capable of forming the core 110 and/or the shell 120 are MgS, MgSe, MgTe, CaS, CaSe, CaTe, SrS, SrSe, SrTe, BaS, BaSe. , BaTe, ZnS, ZnSe, ZnTe, ZnSeS, ZnTeSe, ZnO, CdS, CdSe, CdTe, CdSeS, CdZnS, CdSeTe, CdO, HgS, HgSe, HgTe, CdZnTe, HgCdSe, CdSZnS/ZnS, HgTe, , CdSe/ZnS, CdSe/ZnSe, ZnSe/ZnS, ZnS/CdSZnS, CdS/CdZnS/ZnS, ZnS/ZnSe/CdSe, and combinations thereof. The group III-V compound semiconductor nanocrystals of the periodic table capable of forming the core 110 and/or the shell 120 are AlN, AlP, AlAs, AlSb, GaN, GaP, GaAs, GaSb, InN, InP, InAs, InSb, AlGaAs, InGaAs, InGaP, AlInAs, AlInSb, GaAsN, GaAsP, GaAsSb, AlGaN, AlGaP, InGaN, InAsSb, InGaSb, AlGaInP, AlGaAsP, InGaAsP, InGaAsSb, InAsSbP, AlInAsP, AlGaAsN As It may be selected from the group consisting of combinations.

Group IV-VI compound semiconductor nanocrystals capable of forming the core 110 and/or the shell 120 are TiO ₂ , SnO ₂ , SnS, SnS ₂ , SnTe, PbO, PbO ₂ , PbS, PbSe, PbTe, It may be selected from the group consisting of PbSnTe and combinations thereof. In addition, the I-III-VI compound semiconductor nanocrystals capable of forming the core 110 and/or the shell 120 are AgGaS ₂ , AgGaSe ₂ , AgGaTe ₂ , AgInS ₂ , CuInS ₂ , CuInSe ₂ , Cu ₂ SnS ₃ , CuGaS ₂ , CuGaSe ₂ and combinations thereof may be selected from the group consisting of.

If necessary, the core 110 and/or the shell 120 may include a group III-V compound semiconductor nanocrystal of the periodic table, such as InP/ZnS, InP/ZnSe, GaP/ZnS, and a group II-VI compound semiconductor nanocrystal of the periodic table. Compound semiconductor nanocrystals of different groups may form multiple layers.

In addition, the metal oxide nanocrystals capable of forming the core 110 and/or the shell 120 may be group II or III metal oxide crystals of the periodic table. For example, the metal oxide nanocrystals that may be applied to the core 110 and/or the shell 120 may be selected from the group _{consisting of MgO, CaO, SrO, BaO, Al 2} O _{3 and combinations thereof.} Optionally, the semiconductor nanocrystals constituting the core 110 and/or the shell 120 are doped or undoped with rare earth elements such as Eu, Er, Tb, Tm, Dy or any combination thereof, Alternatively, it may be doped with a transition metal element such as Mn, Cu, Ag, Al, Mg, or any combination thereof.

For example, the core 110 constituting the inorganic light emitting particles 100 such as quantum dots or quantum bars is ZnSe, ZnTe, CdSe, CdTe, InP, ZnCdS, Cu _x In _1-x S, Cu _x In _1-x It may be selected from the group consisting of Se, Ag _x In _1-x S, and combinations thereof, but is not limited thereto. In addition, the shell 120 constituting the inorganic light emitting particles 100 such as quantum dots or quantum bars are ZnS, GaP, CdS, ZnSe, CdS/ZnS, ZnSe/ZnS, ZnS/ZnSe/CdSe, GaP/ZnS, CdS/ It may be selected from the group consisting of CdZnS/ZnS, ZnS/CdSZnS, Cd _{X Zn 1-x} S, and combinations thereof, but is not limited thereto. Alternatively, the inorganic light emitting particle 100 is an alloy quantum dot / quantum rod (alloy QDs / quantum rods; for example, CdS, such as a homogeneous alloy (homogeneous) quantum dots / quantum rods or gradient alloy (gradient alloy) quantum dots / quantum rods; _x Se _1-x , CdSe _x Te _1-x , Zn _x Cd _1-x Se).

In another exemplary embodiment, the inorganic light emitting particles 100 may be quantum dots or quantum rods having a perovskite structure. The inorganic light emitting particles 100 such as quantum dots or quantum rods having a perovskite structure have a core 110 that is a light emitting component, and may have a shell 120 if necessary. For example, the core 110 of the inorganic light emitting particle 100 having a perovskite structure may have a structure of the following general formula.

[general meal]

[ABX ₃ ]

In the general formula, A is organoammonium or alkali metal; B is a metal selected from the group consisting of divalent transition metals, rare earth metals, alkaline earth metals, Pb, Sn, Ge, Ga, In, Al, Sb, Bi, Po, and combinations thereof; X is a halogen atom selected from the group consisting of Cl, Br, I, and combinations thereof.

For example, when A is organic ammonium in the general formula, the inorganic light emitting particles 100 form an organic-inorganic hybrid perovskite structure. Organoammonium constituting general formula A is an amidinium-based organic ion, (CH ₃ NH ₃ ) _n , ((C _x H _2x+1 ) _n NH ₃ ) ₂ (CH ₃ NH ₃ ) _n , (C _n H _2n+1 NH ₃ ) ₂ , (CF ₃ NH ₃ ), (CF ₃ NH ₃ ) _n , ((C _x F _2x+1 ) _n NH ₃ ) ₂ (CF ₃ NH ₃ ) _n , ((C _x F _2x+1 ) _n NH ₃ ) ₂ or (C _n F _2n+1 NH ₃ ) ₂ ) (n is an integer greater than or equal to 1, and x is an integer greater than or equal to 1). As an example, the organoammonium may be unsubstituted or substituted C ₁ -C ₁₀ alkylammonium. Specifically, the organic ammonium constituting A in the general formula may be methyl ammonium or ethyl ammonium. In addition, the alkali metal constituting A in the general formula may be Na, K, Rb, Cs and/or Fr. In this case, the inorganic light emitting particles 100 may form an inorganic metal perovskite structure.

For example, when the core 110 of the inorganic light emitting particle 100 having a perovskite structure has an organic-inorganic hybrid perovskite structure, the organic-inorganic hybrid perovskite is between the organic planes in which the organic cations are located. It has a layered structure in which an inorganic plane in which metal cations are located is sandwiched. At this time, since the dielectric constant difference between the organic material and the inorganic material is large, the excitons are constrained in the inorganic plane constituting the organic-inorganic hybrid perovskite lattice structure, and have the advantage of emitting light having high color purity. In addition, when the core 110 of the inorganic light emitting particle 100 having a perovskite structure has an inorganic hybrid perovskite structure, the stability of the material is improved.

In the core 110 of the inorganic light-emitting particle 100 having a perovskite structure, by adjusting the composition ratio of each component, the type and composition ratio of the constituent components of halogen (X) atoms, a core emitting light in various wavelength bands is synthesized can do. In addition, unlike the core 110 constituting the other quantum dots or quantum rod 100, the perovskite structure has a stable lattice structure, so the core 110 having the perovskite structure has a very stable crystal structure. , and luminous efficiency can be improved.

On the other hand, the organic ligand 130 coupled to the surface of the inorganic light emitting particle 100 is not particularly limited. For example, the organic ligand 130 may be an X-type organic ligand that is an organic ligand having a negative charge (-). For example, the X-type organic ligand 130 having a negative charge (-) is a carboxylate group (carbozylate, -COO ^- ), a phosphonate group (phosphonate) and a thiolate group (thiolate) from the group consisting of It may bind to the surface of the shell 120 through the selected negatively charged functional group.

In one exemplary embodiment, the negatively charged X-type organic ligand 130 may bind to the surface of the shell 120 through a terminal carboxylate group. In this case, a negatively charged functional group constituting the X-type organic ligand 130 , for example, a carboxylate group (-COO ⁻ ) may be coupled to a metal material constituting the shell 120 through electrical interaction. For example, the organic ligand 130 having a terminal carboxylate group _{may be derived from a C 5} -C ₃₀ saturated or unsaturated fatty acid, preferably a C ₈ -C ₂₀ saturated or unsaturated fatty acid. More specifically, the organic ligand 130 having a terminal carboxylate group is octanoic acid (ocatnoic acid, caprylic acid, CH ₃ (CH ₂ ) ₆ COOH), decanoic acid (decanoic acid, CH ₃ (CH ₂ ) ₈ COOH) ), dodecanoic acid, lauric acid (CH ₃ (CH ₂ ) ₁₀ COOH), mydristic acid (1-tetradicanoic acid, CH ₃ (CH ₂ ) ₁₂ COOH), palmitic acid ( palmitic acid, n-hexadecanoic acid, CH ₃ (CH ₂ ) ₁₄ COOH), stearic acid (stearic acid, n-octadecanoic acid, CH ₃ (CH ₂ ) ₁₆ COOH), oleic acid (cis-9- octadekenonic acid, CH ₃ (CH ₂ ) ₇ CH=CH(CH ₂ ) ₇ COOH), and the like, from saturated or unsaturated fatty acids.

In another alternative embodiment, the organic ligand 130 may be an L-type ligand, which is an organic ligand that binds to the surface of the metal material constituting the shell 120 through a lone pair of electrons. For example, the organic ligand 130 having a lone pair of electrons is on the surface of the metal material constituting the shell 120 through a lone pair of a functional group selected from the group consisting of an amine group, a thiol group, a phosphine group, and a phosphine oxide group. They can interact through coordination bonds. For example, when the end of the free ligand 130 having a lone pair of electrons has an amine group (amino group), the metal cation constituting the shell 120 through the lone pair of electrons of the nitrogen atom constituting the amine group through a coordination bond. combine

For example, the organic ligand 130 having a lone pair of electrons may be a C ₁ -C ₁₀ alkyl amine (eg monovalent, divalent or trivalent alkyl amine), preferably a C ₁ -C ₅ straight or branched alkyl amine. Amine, C ₄ -C ₈ alicyclic amine, preferably C ₅ -C ₈ alicyclic amine, C ₅ -C ₂₀ aromatic amine, preferably C ₅ -C ₁₀ aromatic amine, C ₁ -C ₁₀ straight-chain or branched alkyl phosphines (eg monovalent, divalent or trivalent alkyl phosphines), preferably C ₁ -C ₅ straight or branched alkyl phosphines, C ₁ -C ₁₀ straight or branched alkyl Phosphine oxides (eg monovalent, divalent or trivalent alkyl phosphine oxides), preferably C ₁ -C ₅ straight or branched alkyl phosphine oxides, and combinations thereof. have.

In one exemplary embodiment, the free ligand 130 having a lone pair of electrons is 3, such as tris(2-aminoethyl)amine (Tris(2-aminoethy)amine, TAEA), tris(2-(aminomethyl)amine). As well as amines, N-butyl-N-ethylethane-1,2-diamine, ethylene diamine, pentaethylenehexamine , alkyl amines such as oleylamine, cycloaliphatic polyamines such as cyclohexane-1,2-diamine or cyclohexene-1,2-diamine, aromatic amines such as 2,3-diaminopyridine and combinations thereof, but the present invention is not limited thereto.

When forming a thin film such as a light emitting film including the inorganic light emitting particles 100, a solution containing the inorganic light emitting particles 100 is coated on the upper surface of the substrate using an inkjet nozzle, etc., and the curing process is performed at a high temperature of 200 ° C. or higher. It is common to do When the nano-inorganic light-emitting particles 100 such as quantum dots or quantum rods are continuously exposed to high temperatures and react with external oxygen or moisture, a significant portion of the organic ligand 130 bound to the surface of the inorganic light-emitting particles 100 is It is separated and separated, and the core 110 and/or the shell 120 constituting the inorganic light emitting particle 100 is oxidized and deteriorated. A substantial portion of the organic ligands 130 , which have formed coordination bonds on the surface of the shell 120 by high-temperature thermal energy, are separated from the surface of the shell 120 and remain as the free ligands 130b.

Since only a portion of the organic ligand 130a is bound to the surface of the shell 120 constituting the inorganic light emitting particle 100a, the surface of the inorganic light emitting particle 100a is exposed, and the area of the deteriorated inorganic light emitting particle 100a Accordingly, a difference in the coefficient of thermal expansion occurs. In addition, as active oxygen or moisture in the process penetrates into the surface and inside of the inorganic light-emitting particle 100a that is not sufficiently protected by binding only a portion of the organic ligand 130a, the oxidation of the inorganic light-emitting particle 100a is accelerated, and the shell An oxide film 150 is formed on the surface and inside of 120 .

Atoms exposed on the surface of the shell 120 of the inorganic light emitting particle 100a exposed to the outside while binding only a portion of the organic ligand 130a have lone pair electrons that do not participate in chemical bonding. As charges are captured due to the energy level of these surface atoms, a surface defect is caused in the inorganic light emitting particle 100a. In addition, as an oxide film is formed on the surface of the shell 120, the lattice constant of the component constituting the shell 120 and the lattice constant of the component constituting the core 110 are shifted, and the vacant lattice point ( vacancy) is formed.

In other words, as the inorganic light emitting particles 100 before the high temperature process are exposed to high temperature and active oxygen, a significant portion of the organic ligands 130 bound to the surface of the shell 120 are lost and separated and converted into free ligands 130b. do. The oxide film 150 is formed on the surface of the inorganic light emitting particle 100a to which only a portion of the organic ligand 130a is bound and/or surface defects such as vacant lattice dots are caused, and deterioration due to the oxide film 150 and surface defects. The exciton confinement efficiency is lowered in the inorganic light emitting particles 100a. Excitons do not emit light in the oxide film 150 and/or the inorganic light-emitting particles 100a having surface defects, but are quenched, thereby reducing the luminous efficiency of the inorganic light-emitting particles 100a. In addition, there is a problem in that the electrical and optical properties of the inorganic light emitting particles 100a are lost due to the charges trapped on the surface.

However, according to the present invention, a two-step process is added to the thin film including the inorganic light emitting particles 100a to remove surface defects of the inorganic light emitting particles 100a, thereby improving the luminous efficiency of the inorganic light emitting particles. 2A and 2B are schematic diagrams schematically showing equipment including a vacuum chamber that can be applied to a process for producing inorganic light-emitting particles with improved luminous efficiency according to the present invention, respectively. Fig. 2a schematically shows the high-vacuum heat treatment step, and Fig. 2b schematically shows the hydrothermal treatment step. 3 is a schematic diagram schematically showing a process in which deteriorated inorganic light-emitting particles are converted into inorganic light-emitting particles having improved luminous efficiency through the process of the present invention.

Referring to FIGS. 2A and 2B , the coating composition including the inorganic light emitting particles 100 is coated on one surface of the substrate 260 , and a light emitting film 250 is formed by thermal curing treatment. As an example, the coating composition including the initial inorganic light emitting particles 100 is a solution process such as spin coating, drop coating, dip coating, spray coating, roll coating, flow coating, casting process, screen printing or inkjet printing method alone or In combination, it may be coated on one surface of the substrate 260 . A thermal curing process is performed at a high temperature of approximately 200 to 250° C. to volatilize the solvent, and the light emitting film 250 made of the inorganic light emitting particles 100 is formed on one surface of the substrate 260 . In one example, the substrate 260 may be a wafer or other optical sheet.

The light emitting film 250 with or without the substrate 260 is loaded into the vacuum chamber 210 , is seated on the susceptor 212 inside the vacuum chamber 210 , and is mounted. The vacuum chamber 210 is connected to the vacuum pump 220 , the micro plasma processing unit 230 , and the water vapor supply unit 240 , and may be, for example, a chemical vapor deposition (CVD) chamber. In addition, the susceptor 212 on which the light emitting film 250 is seated is made of a ceramic such as AlN in a cylindrical shape extending upward from an exhaust chamber (not shown) connected to the vacuum pump 220 to the supporter (not shown). can be supported by In addition, a heating type heater (not shown) may be embedded in the susceptor 212, the heater (not shown) is powered by a heater power supply (not shown) to heat the susceptor 212, High-vacuum heat treatment may be performed on the light emitting film 250 seated thereon. In addition, an electrode (not shown) may be embedded in the susceptor 212 , and a high frequency power supply (not shown) for bias application may be connected to the electrode (not shown) via a matching device (not shown). . If necessary, the susceptor 212 may be provided with a support pin (not shown) for supporting and elevating the light emitting film 250 seated thereon to be protruding and recessed with respect to the surface of the susceptor 212 . can In addition, a gas introduction part (not shown) is provided on the side wall of the vacuum chamber 210 , and a gas emission hole (not shown) constituting the gas introduction part (not shown) is provided with a hydrogen ion supply line 232 and water vapor, respectively. They are respectively connected to the supply line 242 .

In the high-vacuum heat treatment step, a vacuum condition is implemented in the vacuum chamber 210 by operating the vacuum pump 220 connected to the vacuum chamber 210 . On the other hand, the valves 234 and 244 respectively disposed between the microplasma processing unit 230 and the water vapor supply unit 240 and the vacuum chamber 210 are closed in this step. A high-temperature heat treatment (thermal annealing) is performed on the light emitting film 250 primarily in a high-vacuum condition. In one exemplary embodiment, the high-vacuum heat treatment process ^{may be performed in a vacuum condition of 1X10 -3} torr to 1X10 ^-4 torr for 30 minutes to 1 hour, and may be performed at a temperature of 180 to 230°C.

Referring to FIG. 3 , oxygen molecules and hydrogen molecules contained in the deteriorated inorganic light-emitting particles 100a that cause surface defects by reacting with high-temperature heat treatment and external active oxygen and moisture in the high-temperature thermal curing process are high- It is removed by a vacuum heat treatment process. Accordingly, the oxide film 150 formed on the surface of the deteriorated inorganic light emitting particle 100a becomes a dissociated state 150a and is removed from the surface of the inorganic light emitting particle 100b. However, the surface defects of the inorganic light-emitting particles 100b converted according to the high-vacuum heat treatment process are not completely removed, and by-products generated by the thermal curing process remain in the inorganic light-emitting particles 100b.

In the present invention, after the high-vacuum heat treatment step, the hydrothermal process is performed in the presence of water vapor and, if necessary, hydrogen ions. In order to perform the hydrothermal process, hydrogen ions are supplied from the microplasma processing unit 230 through the hydrogen ion supply line 232 to the vacuum chamber 210 , and from the water vapor supply unit 240 through the water vapor supply line 242 . Water vapor is supplied to the vacuum chamber 210 . A hydrogen ion valve 234 designed in a hydrogen ion supply line 232 connecting the microplasma processing unit 230 and the vacuum chamber 210 to provide hydrogen ions and water vapor into the vacuum chamber 210, respectively; The steam valve 244 designed in the steam supply line 242 connecting the steam supply unit 240 and the vacuum chamber 210 is opened, respectively. For example, the hydrogen ion valve 234 and the water vapor valve 244 may be flow controllers such as a mass flow controller (MFC).

The micro-plasma processing unit 230 supplying hydrogen ions into the vacuum chamber 210 converts hydrogen provided from a hydrogen gas supply unit (not shown) into plasma-treated hydrogen ions at a high temperature. To supply hydrogen gas to the microplasma processing unit 230 and supply hydrogen ions converted by plasma processing from the microplasma processing unit 230 to the inside of the vacuum chamber 210 , nitrogen gas (N ₂ ), helium, argon An inert gas such as , krypton or xenon gas may be provided along with hydrogen ions as a carrier gas or a diluent gas.

In this case, the plasma-treated hydrogen ions may have a volume ratio of about 2 to 4% in the total gas including the dilution gas and the carrier gas. For example, the total gas including hydrogen ions and a carrier gas (diluent gas) may be provided in an amount of approximately 500 to 5000 mL/min (sccm, standard cubic centimeter per minute), and the hydrogen ions are 10 to 200 It may be provided in an amount of sccm. If the supply amount of hydrogen ions to the vacuum chamber 210 is less than 10 sccm, surface defects including the oxide film 150 formed on the deteriorated inorganic light emitting particles 100A may not be removed, and the supply amount of hydrogen ions is 200 sccm. If exceeded, the process may become hazardous due to an oversupply of hydrogen ions.

In order to supply water vapor from the water vapor supply unit 240 to the vacuum chamber 210, a _{carrier gas such as nitrogen gas (N 2} ), an inert gas such as helium, argon, krypton, or xenon gas or a diluent gas to be provided with water vapor. can In one exemplary embodiment, with respect to the total gas supplied to the vacuum chamber 210 (including carrier (dilution) gas for supplying hydrogen ions, carrier (dilution) gas for supplying water vapor, and water vapor), Water vapor may be supplied to the vacuum chamber 210 so that the volume may be 10 to 50 parts per million volume (ppmv), preferably 30 to 50 ppmv. If the amount of water vapor supplied into the vacuum chamber 210 is less than 10 ppmv, the by-product remaining around the inorganic light emitting particles 300 is not removed, and the amount of water vapor supplied into the vacuum chamber 210 is 50 ppmv. If it exceeds, the hydrothermal condition may be violated and the by-product may not be completely removed.

Meanwhile, FIGS. 2A and 2B illustrate a case in which plasma-treated hydrogen ions and water vapor are supplied into the vacuum chamber 210 through separate paths. Alternatively, plasma-treated hydrogen ions and water vapor may be supplied into the vacuum chamber 210 through a single path. Similar to the case described above, hydrogen ions and water vapor may be supplied using a carrier gas or a diluent gas, and hydrogen ions, water vapor and carrier gas may be supplied at a flow rate of approximately 500 to 5000 sccm. At this time, hydrogen ions may be 2 to 4 vol% based on the total gas supplied to the vacuum chamber 210, water vapor is 10 to 50 ppmv, preferably 30 to 50 ppmv, and the dilution gas is 97.997 to 95.995 to 97.997% by volume.

In an exemplary embodiment, hydrothermal treatment may be performed at a temperature of approximately 180 to 230° C. for approximately 5 to 20 minutes in a state in which hydrogen ions converted by plasma treatment and a small amount of water vapor are supplied to the inside of the vacuum chamber 210 . have.

2B and 3 , the oxide film 150a converted into a dissociated state is completely removed by hydrothermal treatment with hydrogen ions supplied from the microplasma processing unit 230 and water vapor supplied from the water vapor supply unit 240 . do. In addition, by hydrothermal treatment, the surface defects and by-products of the inorganic light-emitting particles 100C are completely removed, and the molecules constituting the core 110 and the shell 120 constituting the inorganic light-emitting particles 100C are rearranged. . Accordingly, including some organic ligands of the organic ligands 130b released by the thermal curing process and the organic ligands 130a bonded to the inorganic light emitting particles 100A despite the thermal curing process, the organic ligands having relatively excellent bonding strength The ligand 130d is strongly bound to the surface of the shell 120 of the hydrothermal-treated inorganic light emitting particle 100C. The organic ligand 130d strongly bound to the surface of the shell 120 protects the inorganic light-emitting particles 100C from which surface defects are removed, and improves the stability of the inorganic light-emitting particles 100C.

In addition, surface defects such as void lattice points on the surface of the inorganic light-emitting particle 100C are removed, and the lattice constant shifted from the core 110 and the shell 120 constituting the inorganic light-emitting particle 100C is restored to the initial state, Charges trapped on the surface of the inorganic light emitting particles 100C are minimized. The exciton confinement effect or quantum confinement effect of the inorganic light emitting particle 100C is improved while the charge is not captured on the surface of the inorganic light emitting particle 100C. Accordingly, the high-vacuum heat treatment and hydrothermal treatment of the inorganic light emitting particles 100C have quantum efficiency and luminous efficiency at a level very similar to the quantum efficiency and luminous efficiency of the inorganic light emitting particle 100 before thermal curing.

In one exemplary embodiment, the light emitting film 250 may be a light emitting sheet applied to a liquid crystal display device, a color conversion layer for converting the wavelength of light emitted from a light emitting diode, and/or a light emitting material layer constituting the light emitting diode. . In one exemplary embodiment, the light emitting film 250 may be a light emitting sheet interposed between the liquid crystal panel constituting the liquid crystal display and the backlight unit. In another exemplary embodiment, the light emitting film 250 may be disposed between the light guide plate constituting the backlight unit of the liquid crystal display and the light emitting element disposed on the side surface of the light guide plate. In another exemplary embodiment, the light emitting film 250 may be applied as an optical sheet adjacent to the liquid crystal panel in the backlight unit. In another exemplary embodiment, the light emitting film 250 is disposed adjacent to the light guide plate constituting the backlight unit, disposed above and/or below the optical sheet including the diffusion sheet and the light collecting sheet, or between the optical sheets. may be interposed.

Subsequently, as an example of a light emitting film including inorganic light emitting particles having improved luminous efficiency according to the present invention, a light emitting device into which a color conversion layer including inorganic light emitting particles is introduced and a manufacturing method thereof will be described. 4 is a cross-sectional view schematically illustrating a light emitting display device to which a micro LED is introduced as an example of a light emitting device including a color conversion layer having improved luminous efficiency according to an exemplary embodiment of the present invention.

As shown in FIG. 4 , a light emitting display device 300 according to an exemplary embodiment of the present invention includes a substrate 310 , a thin film transistor Tr and a micro LED D1 disposed on the substrate 310 . It may include an array panel AP, a color conversion layer 380 made of inorganic light emitting particles, and a planarization layer 390 on the color conversion layer 380 .

A gate line (not shown) and a data line (not shown) are disposed on the substrate 310 to provide a red sub-pixel (R-SP) region, a green sub-pixel (G-SP) region, and a blue sub-pixel (B-SP). ) are respectively defined. Each of the sub-pixels R-SP, G-SP, and B-SP regions includes an emission region EA corresponding to a micro LED D1 to be described later and a driving region DA in which the thin film transistor Tr is disposed. This is also defined. In this case, the color conversion layer 380 may be formed to correspond to at least the red sub-pixel (R-SP) area and the green sub-pixel (G-SP) area.

The substrate 310 may be a glass substrate, a thin flexible substrate, or a polymer plastic substrate. For example, the flexible substrate may be formed of any one of polyimide (PI), polyethersulfone (PES), polyethylenenaphthalate (PEN), polyethylene terephthalate (PET), and polycarbonate (PC).

A thin film transistor Tr is formed on the substrate 310 . If necessary, a buffer layer (not shown) may be formed on the upper substrate 310 , and a thin film transistor Tr may be formed on the buffer layer.

Specifically, the semiconductor layer 320 is formed on the substrate 310 . The semiconductor layer 320 may be formed of an oxide semiconductor material. When the semiconductor layer 620 is made of an oxide semiconductor material, a light blocking pattern (not shown) may be formed under the semiconductor layer 320 . The light blocking pattern (not shown) prevents light from being incident on the semiconductor layer 320 and prevents the semiconductor layer 320 from being deteriorated by the light. Optionally, the semiconductor layer 320 may be made of polycrystalline silicon. In this case, the semiconductor layer 320 may be divided into a central channel region and source and drain regions doped with impurities at both edges.

A gate insulating layer 324 made of an insulating material is formed on the semiconductor layer 320 over the entire surface of the substrate 310 . The gate insulating layer 324 may be made of an inorganic insulating material such as _{silicon oxide (SiO x} ) or silicon nitride (SiN _{x ).}

A gate electrode 330 made of a conductive material such as metal is formed on the gate insulating layer 324 to correspond to the center of the semiconductor layer 320 . Although the gate insulating layer 324 is formed on the entire surface of the substrate 310 in FIG. 4 , the gate insulating layer 324 may be patterned in the same shape as the gate electrode 330 .

An interlayer insulating layer 332 made of an insulating material is formed on the entire surface of the substrate 310 on the gate electrode 330 . For example, the interlayer insulating layer 332 _{is formed of an inorganic insulating material such as silicon oxide (SiO x} ) or silicon nitride (SiNx), or made of an organic insulating material such as benzocyclobutene or photo-acryl. can be formed.

The interlayer insulating layer 332 has first and second semiconductor layer contact holes 334 and 336 exposing top surfaces of both sides of the semiconductor layer 320 . The first and second semiconductor layer contact holes 334 and 336 are positioned at both sides of the gate electrode 330 to be spaced apart from the gate electrode 330 . For example, the first and second semiconductor layer contact holes 334 and 336 may also be formed in the gate insulating layer 324 . Optionally, when the gate insulating layer 324 is patterned to have the same shape as the gate electrode 330 , the first and second semiconductor layer contact holes 334 and 336 are formed only in the interlayer insulating layer 332 .

A source electrode 342 and a drain electrode 344 made of a conductive material such as metal are formed on the interlayer insulating layer 332 . The source electrode 342 and the drain electrode 344 are spaced apart from each other with respect to the gate electrode 330 , and are respectively formed on both sides of the semiconductor layer 320 through the first and second semiconductor layer contact holes 334 and 336 , respectively. contact The drain electrode 344 may function as a first electrode that applies a signal to the micro LED D1 .

The semiconductor layer 320 , the gate electrode 330 , the source electrode 342 , and the drain electrode 344 form a thin film transistor Tr, and the thin film transistor Tr functions as a driving element. The thin film transistor Tr illustrated in FIG. 4 has a coplanar structure in which a gate electrode 330 , a source electrode 342 , and a drain electrode 344 are positioned on the semiconductor layer 320 . Alternatively, the thin film transistor Tr may have an inverted staggered structure in which a gate electrode is positioned under a semiconductor layer and a source electrode and a drain electrode are positioned above the semiconductor layer. In this case, the semiconductor layer may be made of amorphous silicon.

Although not shown in FIG. 4 , the gate line and the data line cross each other to define each sub-pixel (R-SP, G-SP, B-SP) region, and a switching element connected to the gate line and the data line is further provided. is formed The switching element is connected to a thin film transistor Tr as a driving element. In addition, the power line is formed to be spaced apart from the data line in parallel, and a storage capacitor is further configured to keep the voltage of the gate electrode 330 of the thin film transistor Tr, which is the driving element, constant during one frame. can In addition, although not shown, a second electrode made of a conductive material may be positioned on the interlayer insulating layer 332 of each subpixel (R-SP, G-SP, B-SP) region.

A first passivation layer 350 is formed on the entire surface of the substrate 310 on the source electrode 342 and the drain electrode 344 . The first passivation layer 350 has a flat top surface and has a drain contact hole 352 exposing the drain electrode 344 of the thin film transistor Tr. In FIG. 4 , the drain contact hole 352 is illustrated as being formed directly on the second semiconductor layer contact hole 336 , but may be formed to be spaced apart from the second semiconductor layer contact hole 336 . The first passivation layer 350 _{is formed of an inorganic insulating material such as silicon oxide (SiO x} ) or silicon nitride (SiNx), or formed of an organic insulating material such as benzocyclobutene or photo-acryl. can be The micro LED D1 is disposed on the first protective layer 350 . For example, the micro LED D1 may be disposed in a recess formed by removing a portion of the first protective layer 350 .

The micro LED D1 includes an n-type semiconductor layer 430 , an active layer 440 having a multi-quantum-well (MQW) structure disposed on the n-type semiconductor layer 430 , and an active layer 440 . ) disposed on the p-type semiconductor layer 450 , the p-type electrode 410 in contact with a portion of the p-type semiconductor layer 450 , the active layer 440 , and a portion of the p-type semiconductor layer 450 . The n-type electrode 420 in contact with a portion of the n-type semiconductor layer 430 exposed by etching may be formed. Optionally, the micro LED D1 is disposed on the undoped GaN layer (not shown) and/or the p-type semiconductor layer 450 disposed under the n-type semiconductor layer 430 , and is transparent conductive. An ohmic contact layer (not shown) made of a material may be further included.

The n-type semiconductor layer 430 is a layer for supplying electrons to the active layer 440 and may be formed by doping the GaN semiconductor layer with n-type impurities such as Si, Ge, Se, Te, or carbon (C). have. The active layer 440 emits light by combining injected electrons and holes. Although not specifically shown in the drawing, in the multi-quantum well structure constituting the active layer 440 , a plurality of barrier layers and well layers are alternately disposed, the well layer is composed of an InGaN layer, and the barrier layer is composed of GaN, not limited The p-type semiconductor layer 450 is a layer for injecting holes into the active layer 440 , and may be formed by doping the GaN semiconductor layer with p-type impurities such as Mg, Zn, and Be. An ohmic contact layer (not shown) is disposed between the p-type GaN layer 450 and the p-type electrode 410 and may be formed of a transparent metal oxide such as ITO, IGZO, or IZO. On the other hand, the p-type electrode 410 and the n-type electrode 420 may be composed of a single layer or multiple layers made of a metal material composed of Ni, Au, Pt, Ti, Al, Cr, alloys thereof, or combinations thereof. can

When a voltage is applied to the p-type electrode 410 and the n-type electrode 420 in the micro LED D1 having such a structure, the active layer is formed from the n-type GaN layer 430 and the p-type GaN layer 450 . Electrons and holes are respectively injected into 440 , and as excitons are generated and destroyed in the active layer 440 , light is emitted and emitted to the outside. The wavelength of light emitted from the micro LED D1 may be adjusted by adjusting the thickness of the barrier layer of the multi-quantum well structure of the active layer 450 . For example, the micro LED D1 may emit blue light, and the micro LED D1 may be formed to a thickness of about 10 to 100 μm.

Although not shown, the micro LED D1 may be manufactured by forming a buffer layer on a substrate and growing a GaN thin film on the buffer layer. In this case, as a substrate for growing the GaN thin film, sapphire, silicon, GaN, silicon carbide (SiC), gallium arsenide (GaAs), zinc oxide (ZnO), or the like may be used. In addition, although the drawings show that the micro LED D1 is disposed on the first protective layer 350, the present invention is not limited to the micro LED D1 having such a specific structure, and a vertical micro LED and a horizontal micro LED Like the LED, micro LEDs of various structures can be applied.

A second protective layer 370 is formed on the first protective layer 350 to which the micro LED D1 is transferred. The second passivation layer 370 _{may be formed of an inorganic insulating material such as silicon oxide (SiO x} ), silicon nitride (SiN _x ), and/or an organic insulating material such as photoacrylic.

Meanwhile, as described above, a drain contact hole 352 and a second electrode contact hole (not shown) are formed in the first protective layer 350 , and a drain electrode 344 constituting the thin film transistor Tr and A second electrode (not shown) is exposed. A metal oxide such as indium-tin-oxide (ITO), indium-zinc-oxide (IZO), indium-tin-zinc oxide (ITZO), or indium-gallium-zinc-oxide (IGZO) is formed on the first passivation layer 350 . A first connection electrode 372 and a second connection electrode 374 made of The drain electrode 344 and the n-type electrode 420 of the micro LED D1 are electrically connected through the drain contact hole 352 and the first connection electrode 372 . The second electrode (not shown) and the p-type electrode 410 of the micro LED D1 are electrically connected through the second electrode contact hole (not shown) and the second connection electrode 374 .

A bank 376 or a reflective insulating layer is disposed in an area other than the emission area EA among the subpixels R-SP, G-SP, and B-SP areas. The bank 376 or the reflective insulating film blocks the light emitted to the side of the micro LED D1 from among the light emitted from the micro LED D1 formed in each of the sub-pixels R-SP, G-SP, and B-SP regions. By reflecting it, the light efficiency of the micro LED D1 can be improved. The bank 376 or the reflective insulating layer may be made of an insulating material including fine particles for light reflection, and an insulating material of _{silicon oxide (SiO x} ) or silicon nitride (SiN _x ) in _{which titanium oxide (TiO 2} ) particles are dispersed. may be made, but is not limited thereto.

In an optional embodiment, a reflective pattern 360 may be further disposed between the first planarization layer 350 and the micro LED D1 . The reflection pattern 360 reflects the light emitted from the lower side of the micro LED D1 among the light emitted from each micro LED D1 back to the upper side, thereby improving the optical efficiency of the plurality of micro LEDs D120. have.

The reflection pattern 124 may be formed of a metal material having high reflection efficiency, for example, aluminum (Al) or silver (Ag), but is not limited thereto. When the reflective pattern 360 is formed under the micro LED D1, a first insulating layer 362 is formed on the reflective pattern 360 to insulate the reflective pattern 360 from the micro LED D1.

Meanwhile, each of the micro LEDs D1 emits blue light from the active layer 440 , and in the red and green sub-pixels R-SP and G-SP regions, the light of a short wavelength goes to the upper portion of each micro LED D1 . A color conversion layer 380 including a red conversion pattern 382 and a green conversion pattern 384 that converts and emits light of a long wavelength is disposed.

This is because blue light has a shorter wavelength compared to red light and green light, and the luminous efficiency of the red and green conversion patterns 382 and 384 for short wavelength light is slightly better, and the red and green conversion patterns 382 and 384 have a shorter wavelength than the light of the short wavelength. Conversion of relatively short-wavelength blue light into relatively long-wavelength red and green light is superior in terms of lifespan, etc., compared to converting relatively long-wavelength red and green light into relatively short-wavelength blue light. because it does However, the micro LED D1 does not necessarily emit blue light, and may be formed of a micro LED that emits red light or green light.

The blue (B) light emitted from the micro LED D1 in the emission area EA of the red sub-pixel R-SP passes through the first color conversion pattern 382 and is converted into the wavelength of the first color. For example, the first color conversion pattern 382 may be formed of inorganic light-emitting particles emitting light in red.

For example, the first color may be red light having a peak wavelength of about 600 nm to 700 nm. However, it should be understood that the wavelength of red light, which is the first color, is not limited to the above example, and includes all wavelength ranges that can be recognized as red (R) light in the art. Most of the blue (B) light emitted from the micro LED D1 in the red sub-pixel (R-SP) region is converted to light of the red (R) wavelength band, and thus the light extraction efficiency is improved.

In addition, the second color conversion pattern 384 is positioned to correspond to the emission area EA of the green sub-pixel G-SP, and is emitted from the micro LED D1 disposed in the green sub-pixel G-SP. The blue (B) light passes through the second color conversion pattern 384 and is converted into the wavelength of the second color. For example, the second color conversion pattern 384 may be formed of inorganic light-emitting particles emitting green light. For example, the second color may be green (red) light having a peak wavelength of about 495 nm to 570 nm. However, it should be understood that the wavelength of green light, which is the second color, is not limited to the above example, and includes all wavelength ranges that can be recognized as green (G) light in the art. Most of the blue (B) light emitted from the micro LED D1 in the green sub-pixel (R-SP) region is converted into light of the green (G) wavelength band, so that light extraction efficiency is improved.

On the other hand, in the blue sub-pixel (B-SP) region, since the blue (B) light is emitted from the micro LED D1 as it is, the color conversion layer is not formed in the blue sub-pixel (B-SP) region. For example, in response to the first and second color conversion patterns 382 and 384 and the color filter 388, a transparent resin, for example, is formed on the micro LED D1 formed in the blue sub-pixel B-SP. An optically clear adhesive (OCA) may be disposed.

The color conversion layer 380 including the first color conversion pattern 382 and the second color conversion pattern 384 includes a color conversion material that is an inorganic light emitting particle 100C (refer to FIG. 5D ). As an example, the inorganic light emitting particles 100C may be quantum dots and/or quantum bars.

In an optional embodiment, the color conversion layer 380 is formed over the red and green sub-pixels R-SP and G-SP regions, and may be formed of a single color conversion layer made of red-green inorganic light-emitting particles. In addition, the color conversion layer is formed in all areas of the red, green, and blue sub-pixels (R-SP, G-SP) except for the blue sub-pixel (B-SP) area, and a single color conversion layer made of red inorganic light-emitting particles. may be made with

In addition, color filters 388 may be formed on the color conversion patterns 382 and 384 formed in the red and green sub-pixels R-SP and G-SP, respectively. The color filter 388 includes a pigment or dye that transmits only light of a specific wavelength band among the light generated by the micro LED D1. By adopting the color filter 388, the light emitting display device 300 can realize full-color.

For example, the color filter 388 may be formed of a yellow dye or a yellow pigment. Optionally, the color filter pattern formed in the red sub-pixel (R-SP) area may be formed of a red dye or red pigment, and the color filter pattern formed in the green sub-pixel (G-SP) area may be formed of a green dye or green pigment. have. Accordingly, the blue (B) light emitted from the micro LED D1 in the red and green sub-pixels (R-SP, G-SP) region passes through each color filter pattern, and the red (R) light and green light, respectively, pass through each color filter pattern. (G) light is emitted, and blue (B) light is emitted in the blue sub-pixel (B-SP) region.

A third protective layer 390 is formed on the bank 376 or the reflective insulating film, the color conversion layer 380 and the color filter 388 , and the transparent resin. For example, the third passivation layer 390 _{may be formed of an inorganic insulating material such as silicon oxide (SiO x} ), silicon nitride (SiN _x ), and/or an organic insulating material such as photoacrylic. If necessary, an encapsulation film (not shown) serving as an encapsulation or barrier may be disposed on the third protective layer 390 . In another exemplary embodiment, the light emitting display device 300 may be a bottom-emission type. In this case, the color filter may be disposed between the substrate 310 and the micro LED D1 , and the color conversion layer may be disposed between the micro LED D1 and the color filter.

5A to FIG. 5A to FIG. 5A to FIG. 5A to FIG. 5A for a process of manufacturing an array panel including a micro LED D1 and a color conversion layer 380 including an inorganic light emitting particle having improved luminous efficiency according to the present invention. It will be described with reference to 5d.

As shown in FIG. 5A , the thin film transistor Tr is formed in the driving area DA above the substrate 310 in which the sub-pixels R-SP, G-SP, and B-SP areas are defined, and the light emitting area ( EA) to form and prepare an array panel (AP) by transferring the micro LED (D1). For example, an amorphous silicon layer and a protective layer are disposed in the driving region DA on the substrate 310 , and heat of about 900 to 1300° C. applied to the epitaxial growth process is applied to convert the polysilicon layer. Then, the protective layer is removed, and a thin film transistor Tr is formed on the polysilicon layer.

Although the structure and manufacturing method of the thin film transistor element Tr made of polysilicon are very diverse, for example, it may be manufactured through the following process. A gate insulating film 324 is formed on the polysilicon layer. Thereafter, a gate electrode 330 is formed on the gate insulating layer 324 . Thereafter, ions are implanted into the polysilicon layer to form a source region and a drain region. Thereafter, an interlayer insulating layer 332 is formed on the gate insulating layer 324 and the gate electrode 330 . Thereafter, first and second semiconductor layer contact holes 334 and 336 are formed in the gate insulating layer 324 and the interlayer insulating layer 332 over the source region and the drain region. Thereafter, first and second semiconductor layer contact holes 334 and 336 are formed on the interlayer insulating layer 332 . A source electrode 342 and a drain electrode 344 connected to the source region and the drain region through the second semiconductor layer contact holes 334 and 336 are formed.

On the other hand, in the light emitting area EA, a reflective pattern 360 and an insulating layer 362 are formed on the first passivation layer 350, and a part of the first passivation layer 350 is removed to form a microcavity. The LED D1 is transferred, and the micro LED D1 is disposed in the light emitting area EA.

As an example, the micro LED D1 may be manufactured through epitaxial growth on a substrate. By the epitaxial growth process, the n-type semiconductor layer 430 , the active layer 440 , and the p-type semiconductor layer 450 each made of a nitride semiconductor may be formed. For example, the micro LED D1 made of a nitride-based semiconductor material may be formed on a sapphire growth substrate through a metal organic chemical vapor deposition (MOCVD) process, but is not limited thereto. For example, it may be implemented through a method such as Molecular Beam Epitaxy (MBE), Plasma Enhanced Chemical Vapor Deposition (PECVD), Vapor Phase Epitaxy (VPE), or the like. MOCVD process may be performed at about 900 ~ 1300 ℃.

Next, a first connection electrode 372 connecting the drain electrode 342 of the thin film transistor Tr and the n-type electrode 420 of the micro LED D1, and the p-type electrode of the micro LED D1 ( A second connection electrode 374 connecting the 410 and the second electrode (not shown) is formed. For example, the first connection electrode 372 and the second connection electrode 374 are formed on the substrate 310 on which the thin film transistor Tr and the micro LED D1 driven by the thin film transistor Tr are disposed. , a process of forming the first passivation layer 350 , a process of forming a drain contact hole 352 and a second electrode contact hole (not shown), and a process of depositing a metal.

As shown in FIG. 5B , in each subpixel R-SP, G-SP, and B-SP in which the array panel AP is formed, the bank 376 or a reflective insulating film is photoresist to the outside of the light emitting area EA. formed using the process.

Next, as shown in FIG. 5C , the color conversion layer 380 including the inorganic light emitting particles 100a is applied to the micro LED constituting the light emitting area EA of the red and green subpixels R-SP and G-SP. It is formed on top of (D1). For example, the first color conversion pattern 382 including red inorganic light emitting particles is disposed in the light emitting area EA of the red subpixel R-SP area, and the light emitting area of the green subpixel G-SP area is disposed. In (EA), a second color conversion pattern 384 including green inorganic light emitting particles is disposed.

For example, in order to form the color conversion layer 380, a coating solution including the red or green inorganic light emitting particles 100A is applied using a solution process to form the red and green sub-pixels (R-SP, G-SP). After coating on the top of the micro LED (D1) of the area, a thermal curing process is performed to volatilize the solvent, and the color conversion pattern 382 is converted into the light emitting area (EA) of the red and green sub-pixels (R-SP, G-SP). , 384) may be formed as a color conversion layer 380 . The solution process for forming the color conversion layer 380 is not particularly limited, and a solution process such as spin coating, drop coating, dip coating, spray coating, roll coating, flow coating, casting process, screen printing or inkjet printing method is used. They may be used alone or in combination. Then, by volatilizing the solvent in the coating solution by a thermal curing process, the color conversion layer 380 in the form of a thin film made of the inorganic light emitting particles 100A is applied to the red and green sub-pixels (R-SP, G-SP) regions. It is formed on the formed micro LED (D1).

Next, a color filter 388 is formed on the color conversion layer 380 using a process such as photoresist. On the other hand, a color conversion pattern and a color filter are not formed on the micro LED D1 of the blue sub-pixel (B-SP) area, and a transparent resin (reference numeral not assigned) is disposed corresponding to the color conversion pattern and the color filter. can

At this time, the inorganic light emitting particles 100A forming each of the color conversion patterns 382 and 384 react with a high-temperature thermal curing process and external active oxygen and moisture, so that a significant portion of the organic ligands are released from the organic ligands. It is lost to (130b), and only a portion of the organic ligand 130a binds to the surface of the shell 120, thereby reducing stability. In addition, as the oxide film 150 is formed on the surface of the inorganic light emitting particle 100A or surface defects such as voids are caused, the luminous efficiency is lowered.

However, according to the present invention, the array panel AP on which the color conversion layer 380 is formed is loaded into the vacuum chamber 220 (refer to FIG. 2A ), and firstly heat-treated in a high-vacuum condition (eg, 1X10) ^-3 torr to 1X10 ^-4 torr under vacuum conditions, 180 to 230°C for 30 minutes to 1 hour), and secondly, hydrothermal heat in the presence of hydrogen ions converted by plasma treatment and a small amount of water vapor treatment (e.g., 2 to 4% by volume of hydrogen ions and 10 to 50 ppmv of water vapor in the total gas supplied to the vacuum chamber, and approximately 5 to 20 minutes at a temperature of 180 to 230°C) is performed ( see Fig. 2b). The high-vacuum heat treatment and hydrothermal treatment for the array panel AP on which the color conversion layer 380 is formed may be substantially the same as the above-described heat treatment and hydrothermal treatment for the optical film 250 .

Accordingly, as shown in FIG. 5D , when the two-step heat treatment process is completed, the inorganic light emitting particles 100C constituting the color conversion layer 380 are in a state in which the oxide film and surface defects are removed. In addition, while a plurality of organic ligands 130d are strongly bound to the surface of the shell 120 constituting the inorganic light-emitting particles 100C converted by the two-step heat treatment process, the inorganic light-emitting particles 100C are stabilized. Since the exciton confinement effect and the quantum confinement effect are not reduced in the stabilized inorganic light emitting particle 100C, the luminous efficiency of the inorganic light emitting particle 100C may be improved.

Meanwhile, in FIGS. 5C and 5D , the high-vacuum heat treatment process and the hydrothermal treatment process are illustrated in a state in which the color filter 388 and the encapsulation film 390 are formed on the color conversion layer 380 . Alternatively, the high-vacuum heat treatment process and the hydrothermal treatment process may be performed in a state in which only the color conversion layer 380 is formed on the micro LED D1.

A light emitting display device in which a micro LED is formed in each sub-pixel as a light emitting diode has been described with reference to FIGS. 4A to 5 . The light emitting diode that emits light in the light emitting display device is not limited to the micro LED, but this will be described. 6 is a cross-sectional view schematically illustrating a light emitting display device to which a light emitting diode is introduced as a light emitting device including a color conversion layer having improved luminous efficiency according to another exemplary embodiment of the present invention.

The light emitting display device 500 has a substrate 510 on which red, green, blue, and white subpixels R-SP, G-SP, B-SP, and W-SP are defined, and faces the first substrate 510 . and an encapsulation film 590 . The substrate 510 has red, green, blue, and white sub-pixel (R-SP, G-SP, B-SP, W-SP) regions defined, and each sub-pixel region has a light emitting diode (D2) disposed therein. It may be divided into a light emitting area EA and a driving area DA in which the thin film transistor Tr is formed. A thin film transistor Tr and a light emitting diode D2 are disposed on the substrate 510 to form an array panel AP. In the red and green sub-pixels (R-SP, G-SP) regions of the encapsulation film 590 , a color conversion layer 580 made of inorganic light emitting particles is positioned.

The substrate 510 may be made of a transparent material. For example, the substrate 510 may be a glass substrate, a thin flexible substrate, or a polymer plastic substrate. The encapsulation film 590 may be made of a transparent or opaque material. For example, the encapsulation film 590 may be made of glass, plastic such as polyimide, metal foil, or the like.

A polarizing plate (not shown) for reducing reflection of external light may be attached to the display surface of the light emitting display device 500 , for example, the lower portion of the substrate 510 and/or the upper surface of the encapsulation film 590 . . For example, the polarizing plate (not shown) may be a circular polarizing plate, and may be a right-handed circular polarization plate or a left-handed circular polarization plate. Optionally, a cover window (not shown) may be attached on the encapsulation film 590 or a polarizing plate (not shown). In this case, when the substrate 510 and the cover window (not shown) are made of a flexible material, a flexible display device may be configured.

Also, an adhesive layer 560 may be disposed between the encapsulation film 590 and the light emitting diode D2 , for example, between the color conversion layer 580 and the light emitting diode D2 . The adhesive layer 560 may be formed of OCR, but is not limited thereto. Although not shown, on the substrate 510 , gate lines and data lines crossing each other defining regions of the red, green, blue, and white subpixels R-SP, G-SP, B-SP, and W-SP are formed. A power line extending parallel to and spaced apart from the gate line or the data line is formed.

A thin film transistor Tr as a driving element is positioned in each of the subpixels R-SP, G-SP, B-SP, and W-SP. For example, the thin film transistor Tr may correspond to the central region of the semiconductor layer 520 disposed on the substrate 510 , the gate insulating layer 524 formed on the semiconductor layer 520 , and the semiconductor layer 520 . The formed gate electrode 530 , the interlayer insulating layer 532 covering the gate electrode 530 , and the source electrode 542 contacting the semiconductor layer 520 through the first and second semiconductor layer contact holes 534 and 536 . and a drain electrode 544 .

The light emitting diode D2 is electrically connected to the thin film transistor Tr as a driving element. In addition, each subpixel (R-SP, G-SP, B-SP, W-SP) has a thin film transistor (Tr), a switching element electrically connected to a gate line, and a data line, and a switching element and a power wiring. A connected storage capacitor may be formed on the substrate 510 . When the switching element is turned on according to the gate signal applied to the gate line, the data signal applied to the data line passes through the switching element to the gate electrode 530 of the thin film transistor Tr as the driving element and the storage. applied to one electrode of the capacitor.

The thin film transistor Tr is turned on according to the data signal applied to the gate electrode 530 , and as a result, a current proportional to the data signal is generated from the power wiring through the thin film transistor Tr as a driving element to the light emitting diode D2 . and the light emitting diode D2 emits light with a luminance proportional to the current flowing through the thin film transistor Tr.

A protective layer 550 is formed on the thin film transistor Tr. The protective layer 550 has a flat top surface and has a drain contact hole 552 exposing the drain electrode 544 of the thin film transistor Tr.

The light emitting diode D is located on the planarization layer 550 and includes a first electrode 610 connected to the drain electrode 544 of the thin film transistor Tr, and a light emitting layer sequentially stacked on the first electrode 610 ( 620 and a second electrode 630 .

The first electrode 610 is formed separately for each sub-pixel (R-SP, G-SP, B-SP, W-SP) area. The first electrode 610 may be an anode, and may be made of a conductive material having a relatively large work function value, for example, a transparent conductive oxide (TCO).

Meanwhile, when the light emitting display device 500 according to the present embodiment is a top-emission type, a reflective electrode or a reflective layer may be further formed under the first electrode 610 . For example, the reflective electrode or the reflective layer may be made of an aluminum-palladium-copper (APC) alloy. Also, a bank layer 554 covering an edge of the first electrode 610 is formed on the planarization layer 550 . The bank layer 660 exposes the center of the first electrode 710 corresponding to the pixel area.

A light emitting layer 620 is formed on the first electrode 610 . In one exemplary embodiment, the light emitting layer 620 may have a single-layer structure of an emitting material layer (EML). For example, the light emitting material layer (EML) constituting the light emitting layer 620 may be made of inorganic light emitting particles such as quantum dots and/or quantum bars, or may be made of an organic light emitting material serving as a host and/or dopant. For example, the organic dopant may include a phosphorescent material, a fluorescent material, and/or a delayed fluorescent material emitting light in red (R), green (G), blue (B), or the like. Alternatively, the emission layer 620 may include a plurality of charge transfer layers and/or exciton blocking layers in addition to the emission material layer (see FIG. 8 ). There may be one light emitting layer 620, and two or more light emitting layers may form a tandem structure.

A second electrode 630 is formed on the substrate 410 on which the emission layer 620 is formed. The second electrode 630 is located on the entire surface of the display area and is made of a conductive material having a relatively small work function value and may be used as a cathode. Materials and thicknesses of the first electrode 610 , the light emitting layer 620 , and the second electrode 630 constituting the light emitting diode D2 may be substantially the same as those of FIG. 8 .

In addition, although not shown, corresponding to each of the red, green, and blue sub-pixel (R-SP, G-SP, B-SP) regions on the encapsulation film 590, the red, green, and blue color filter patterns are formed. A color filter may be disposed. The white light emitted from the light emitting diode D2 in the red, green, and blue subpixels R-SP, G-SP, and B-SP passes through the red, green and blue color filter patterns (not shown), respectively, Red, green, and blue light are respectively displayed through the encapsulation film 590 , and white light is displayed through the encapsulation film 590 in the white sub-pixel (W-SP) region.

The first color conversion pattern 582 and the second color conversion pattern 582 and the second light emitting area EA corresponding to the light emitting diode D2 among the red and green subpixels R-SP and G-SP areas of the encapsulation film 590, respectively A color conversion layer 580 including a color conversion pattern 584 is disposed. That is, when white (W) light is emitted from the light emitting diode D2 , the color conversion layer 580 is formed in the red and green sub-pixels R-SP and G-SP regions, and the blue and white sub-pixels ( B-SP, W-SP) is not formed.

Similar to the color conversion patterns 382 and 384 described in FIG. 4 , the first and second color conversion patterns 582 and 584 each include an inorganic light-emitting particle 100C that emits light in red and an inorganic light-emitting particle that emits light in green. 100C, see FIG. 7C). The first color conversion pattern 582 converts light emitted from the light emitting diode D2 into a first color, for example, red (R) light having a peak wavelength range of 600 nm to 700 nm. The second color conversion pattern 584 converts the light emitted from the light emitting diode D2 into a second color, for example, green (G) light having a peak wavelength range of about 495 nm to 570 nm.

The white (W) light emitted from the light emitting diode D2 passes through the first color conversion pattern 582 formed to correspond to the red subpixel (R-SP) region, and among the light constituting the white (W) light. As the light of the blue (B) wavelength and the green (G) wavelength, which is light of a shorter wavelength band than the red (R) light, is converted into light of the red (R) wavelength, it is emitted to the encapsulation film 590 to improve the light extraction efficiency. do.

In addition, the white (W) light emitted from the light emitting diode D2 passes through the second color conversion pattern 584 positioned to correspond to the green sub-pixel (G-SP) region and constitutes the white (W) light. Light of a blue (B) wavelength, which is light of a shorter wavelength band than green (G) light, is converted into light of a green (G) wavelength, and is emitted to the encapsulation film 590 to improve light extraction efficiency.

Meanwhile, the color conversion layer 580 is not formed in the blue subpixel B-SP. In general, when converting a wavelength of light, it is difficult to convert light of a relatively low energy (light of a long wavelength) into light of a relatively high energy (light of a short wavelength). For this reason, since high-energy light is emitted from the blue subpixel (B-SP), it is not easy to convert the white (W) light into the blue (B) light through the color conversion layer 580. In addition, the white sub-pixel (B-SP) is not easy to convert. A color filter layer (not shown) and a color conversion layer 580 are not formed in the pixel W-SP region.

7A to 7C for a process of manufacturing an array panel including a light emitting diode D2 and a light emitting display device 500 in which a color conversion layer 580 including inorganic light emitting particles having improved luminous efficiency is formed Explain.

First, as shown in FIG. 7A , the thin film transistor Tr in the driving area DA above the substrate 510 in which the respective subpixels R-SP, G-SP, B-SP, and W-SP areas are defined. ), and arrange the light emitting diodes D2 in the light emitting area EA to form and prepare the array panel AP. The structure and formation process of the thin film transistor Tr constituting the array panel AP may be substantially the same as described with reference to FIG. 5A .

In order to form the light emitting diode D2, the first electrode 610 is patterned on the passivation layer 550 into regions of each of the sub-pixels R-SP, G-SP, B-SP, and W-SP. When the first electrode 610 is patterned, the light emitting area EA of each of the sub-pixels R-SP, G-SP, B-SP, and W-SP is formed using, for example, a photoresist process. The bank layer 554 is patterned outward. The bank layer 554 may be formed of a resin such as polyimide, but is not limited thereto. Next, using a solution process or a deposition process on the first electrode 610 , the light emitting layer 620 is formed into the light emitting area EA of each of the subpixels R-SP, G-SP, B-SP, and W-SP. ) and forming the second electrode 620 on the light emitting layer 620 on the entire surface of the substrate 510 to manufacture the array panel AP.

Subsequently, as shown in FIG. 7B , the inorganic light-emitting particles 100a are areas corresponding to the light-emitting areas EA of the red and green sub-pixels R-SP and G-SP on one surface of the encapsulation film 590 . A color conversion layer 580 including a color conversion layer 580 is formed, and the color conversion layer 580 formed on one surface of the encapsulation film 590 and the array panel AP are laminated through an adhesive layer 550 .

For example, a first color conversion pattern 582 including red inorganic light emitting particles is disposed in the light emitting area EA of the red sub-pixel R-SP area, and the light emitting area of the green sub-pixel G-SP area is disposed. In (EA), a second color conversion pattern 584 including green inorganic light emitting particles is disposed. The light emitting area (EA) of the red and green sub-pixels (R-SP, G-SP) in the encapsulation film 590 using a coating solution containing the red or green inorganic light-emitting particles 100A using a solution process. Coating with an area corresponding to , and volatilizing the solvent by performing a thermal curing process, from one surface of the encapsulation film 590 to the light emitting area EA of the red and green sub-pixels R-SP and G-SP A color conversion layer 580 including color conversion patterns 582 and 584 may be formed. A solution process for forming the color conversion layer 380 may be substantially the same as that of the light emitting display device including the aforementioned micro LED (D1, see FIG. 5B ).

At this time, the inorganic light emitting particles 100A forming each of the color conversion patterns 582 and 584 react with a high-temperature thermal curing process and external active oxygen and moisture, so that a significant portion of the organic ligands are liberated from the organic ligands. It is lost to (130b), and only a portion of the organic ligand 130a binds to the surface of the shell 120, thereby reducing stability. In addition, as the oxide film 150 is formed on the surface of the inorganic light emitting particle 100A or surface defects such as voids are caused, the luminous efficiency is reduced.

However, according to the present invention, the array panel AP and the display panel on which the color conversion layer 580 is formed on one surface of the encapsulation film 590 are loaded into the vacuum chamber 220 (refer to FIG. 2A ), and firstly The heat treatment is performed under high-vacuum conditions, and secondly, hydrothermal treatment is performed under conditions in which hydrogen ions converted by plasma treatment and a small amount of water vapor exist (see FIG. 2B ). The high-vacuum heat treatment and hydrothermal treatment for the display panel in which the color conversion layer 580 is formed on one surface of the array panel AP and the encapsulation film 590 is substantially the same as the heat treatment and hydrothermal treatment for the optical film 250 . The same can be done.

Accordingly, as shown in FIG. 7c, when the two-step heat treatment process is completed, the inorganic light-emitting particles 100C constituting the color conversion layer 580 have an oxide film and surface defects removed, and the inorganic light-emitting particles 100C are formed. A plurality of organic ligands 130d are strongly bound to the surface of the shell 120 constituting it. Since the exciton confinement effect and the quantum confinement effect are not reduced in the stabilized inorganic light emitting particle 100C, the luminous efficiency of the inorganic light emitting particle 100C may be improved.

In the above-described embodiment, a light-emitting device having a light-emitting film such as a light-emitting sheet, a color conversion layer, and a method for manufacturing the same have been described. Alternatively, the process according to the present invention can also be applied when manufacturing an inorganic light emitting diode. 8 is a cross-sectional view schematically illustrating an inorganic light emitting diode including a light emitting material layer having improved light emitting efficiency according to another exemplary embodiment of the present invention.

As shown in FIG. 8 , the inorganic light emitting diode D according to an exemplary embodiment of the present invention includes a first electrode 710 , a second electrode 730 facing the first electrode 710 , and a first The light emitting layer 720 is positioned between the electrode 710 and the second electrode 730 . The emission layer 720 includes an emitting material layer (EML) 740 . In an alternative embodiment, the light emitting layer 720 includes a first charge transfer layer (CTL1, 750 ) positioned between the first electrode 710 and the light emitting material layer 740 , and the light emitting material layer 740 . ) and a second charge transfer layer (CTL2, 760) positioned between the second electrode 730 . In addition, the light emitting layer 720 is a first exciton blocking layer located between the light emitting material layer 740 and the first charge transfer layer 750 (electron blocking layer (EBL, not shown)) and / or A second exciton blocking layer, a hole blocking layer (HBL, not shown), positioned between the light emitting material layer 740 and the second charge transfer layer 760 may be further included.

The first electrode 710 may be an anode such as a hole injection electrode. The first electrode 710 may be formed on a substrate 510 (refer to FIG. 6 ) that may include glass or a polymer material. For example, the first electrode 710 may be formed of a conductive material having a relatively high work function value, for example, a transparent conductive oxide (TCO). Specifically, the first electrode 710 is indium-tin-oxide (ITO), indium-zinc-oxide (IZO), indium-tin-zinc oxide (ITZO), indium-copper-oxide (ICO), SnO ₂ , doped or undoped metal oxides including In ₂ O ₃ , Cd:ZnO), F:SnO ₂ , In:SnO ₂ ), Ga:SnO _{2 ,} and Al:ZnO(AZO). Optionally, the first electrode 710 is formed of nickel (Ni), platinum (Pt), gold (Au), silver (Ag), iridium (Ir) or carbon nanotube (CNT) in addition to the above-described metal oxide. It may include more.

The second electrode 730 may be a cathode such as an electron injection electrode. For example, the second electrode 730 may include Ca, Ba, Ca/Al, LiF/Ca, LiF/Al, BaF ₂ /Al, CsF/Al, CaCO ₃ /Al, BaF ₂ /Ca/Al, Al, Mg, It may be made of Au:Mg or Ag:Mg. For example, the first electrode 710 and the second electrode 730 may each be formed to a thickness of 5 to 300 nm, preferably 10 to 200 nm, but is not limited thereto.

In one exemplary embodiment, when the inorganic light emitting diode D3 is a bottom light emitting type, the first electrode 710 may be made of a transparent conductive metal such as ITO, IZO, ITZO, or AZO, and the second electrode 730 may be made of a transparent conductive metal such as ITO, IZO, ITZO, or AZO. ) may be Ca, Ba, Ca/Al, LiF/Ca, LiF/Al, BaF ₂ /Al, Al, Mg, Ag:Mg alloy, or the like.

The light emitting material layer 740 is made of inorganic light emitting particles 100C (refer to FIG. 9D ) that may be quantum dots or quantum bars. When the light-emitting material layer 740 includes inorganic light-emitting particles 100C such as quantum dots or quantum bars, the light-emitting material layer 740 is formed using a solution in which the inorganic light-emitting particles are dispersed in a non-polar solvent and/or a polar solvent. can do.

The first charge transfer layer 750 may be a hole transfer layer that supplies holes to the light emitting material layer 740 . For example, the first charge transfer layer 750 may include a hole injection layer (HIL) 752 positioned adjacent to the first electrode 710 between the first electrode 710 and the light emitting material layer 740 . and a hole transport layer (HTL) 754 positioned adjacent to the light emitting material layer 740 between the first electrode 710 and the light emitting material layer 740 .

The hole injection layer 752 facilitates the injection of holes from the first electrode 710 to the light emitting material layer 740 . For example, the hole injection layer 752 may include poly(ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS); 4,4',4"-tris(diphenylamino)triphenylamine (TDATA) doped with tetrafluoro-tetracyano-quinodimethane (F4-TCNQ); p-doped, e.g. zinc phthalocyanine (ZnPc) doped with F4-TCNQ phthalocyanine: N,N'-diphenyl-N,N'-bis(1-naphtyl)-1,1'-biphenyl-4,4"-diamine(α-NPD) doped with F4-TCNQ; It may be made of an organic material selected from the group consisting of hexaazatriphenylene-hexanitrile (HAT-CN) and combinations thereof, but the present invention is not limited thereto. For example, a dopant such as F4-TCNQ may be doped in a ratio of 1 to 30 wt% based on the host. The hole injection layer 752 may be omitted depending on the structure and shape of the inorganic light emitting diode D3.

The hole transport layer 754 transfers holes from the first electrode 710 to the light emitting material layer 740 . The hole transport layer 254 may be formed of an inorganic material or an organic material. When the hole transport layer 754 is made of an organic material, the hole transport layer 754 is 4,4'-bis(p) such as 4,4'-Bis(N-carbazolyl)-1,1'-biphenyl(CBP, CBDP). -carbazolyl)-1,1'-biphenyl compounds; N,N'-Di(1-naphthyl)-N,N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine(NPB, NPD), N,N'-diphenyl-N,N '-bis(3-methylphenyl)-(1,1'-biphenyl)-4,4'-diamine(TPD), N,N'-bis(3-methylphenyl)-N,N'-bis(phenyl)- spiro(spiro-TPD), N,N'-di(4-(N,N'-diphenyl-amino)phenyl)-N,N'-diphenylbenzidine(DNTPD), 4,4',4"-tris(N -carbazolyl)-triphenylamine(TCTA), tetra-N-phenylbenzidine(TPB), tris(3-methylphenylphenylamino)-triphenylamine(m-MTDATA), poly(9,9'-dioctylfluorenyl-2,7-diyl)-co- (4,4'-(N-(4-sec-butylphenyl)diphenylamine(TFB), poly(4-butylphenyl-dipnehyl amine)(poly-TPD), spiro-NPB, and combinations thereof. Aryl amines that are aromatic amines or polynuclear aromatic amines; conductive polymers such as polyaniline, polypyrrole, and PEDOT:PSS; poly(N-vinylcarbazole) (PVK) and its derivatives, poly[2- methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene](MEH-PPV) or poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylenevinylene](MOMO-PPV) ) such as poly(para)phenylenevinylene and its derivatives, polymethacrylate and its derivatives, poly(9,9-octylfluorene) and its derivatives, poly(spiro-flu) Oren )) and polymers such as derivatives thereof; metal complexes such as copper phthalocyanine (CuPc); and an organic material selected from the group consisting of combinations thereof.

When the hole transport layer 754 is made of an inorganic material, the hole transport layer 754 may be made of an inorganic material selected from the group consisting of metal oxide nanocrystals, non-oxidized equivalent nanocrystals, and combinations thereof. For example, metal oxide nanocrystals that may be used in the hole transport layer 254 are ZnO, TiO ₂ , CoO, CuO, Cu ₂ O, FeO, In ₂ O ₃ , MnO, NiO, PbO, SnOx, Cr ₂ O ₃ , _V2 O ₅ , Ce ₂ O ₃ , MoO ₃ , Bi ₂ O ₃ , ReO _{3 ,} and combinations thereof, but is not limited thereto. Meanwhile, non-oxidized equivalent nanocrystals _{include, but are not limited to, copper thiocyanate (CuSCN), Mo 2} S, p-type GAN, and the like. Optionally, the hole transport layer 754 may be doped with the above-described metal oxide nanocrystals and non-oxidized equivalent nanocrystals with a p-type dopant. For example, the p-type dopant may include Li+, Na+, K+, Sr+, Ni ²⁺ , Mn ²⁺ , Pb ²⁺ , Cu ⁺ , Cu ²⁺ , Co ²⁺ , Al ³⁺ , Eu ³⁺ , In ³⁺ , Ce ³⁺ , Er ³⁺ , Tb ³⁺ , Nd ³⁺ , Y ³⁺ , Cd ²⁺ , Sm ³⁺ , N, P, As, and combinations thereof, but is not limited thereto.

In FIG. 8 , the first charge transport layer 750 , which may be a hole transport layer, is divided into a hole injection layer 752 and a hole transport layer 754 . Alternatively, the first charge transfer layer 750 may be formed of one layer. For example, the first charge transport layer 750 may include only the hole transport layer 754 without the hole injection layer 752 , and doping the hole transport organic material with a hole injection material (eg PEDOT:PSS). may be done.

The second charge transfer layer 760 is positioned between the light emitting material layer 740 and the second electrode 730 . The second charge transfer layer 760 may be an electron transfer layer that supplies electrons to the light emitting material layer 740 . In one exemplary embodiment, the second charge transfer layer 760 is an electron injection layer positioned adjacent to the second electrode 730 between the second electrode 730 and the light emitting material layer 740 . an EIL, 762 , and an electron transport layer (ETL) 764 positioned adjacent to the light emitting material layer 740 between the second electrode 730 and the light emitting material layer 740 .

The electron injection layer 762 facilitates electron injection from the second electrode 730 into the light emitting material layer 740 . For example, the electron injection layer 762 is made of a material doped or combined with fluorine to a metal such as Al, Cd, Cs, Cu, Ga, Ge, In, Li, or Al, Mg, In, Li, Ga _{Titanium dioxide (TiO 2} ), zinc oxide (ZnO), zirconium oxide (ZrO), tin oxide (SnO ₂ ), tungsten oxide (WO ₃ ), tantalum oxide (Ta), doped or undoped with , Cd, Cs, Cu, etc. ₂ O ₃ ), such as a metal oxide.

The electron transport layer 764 transfers electrons to the light emitting material layer 740 . The electron transport layer 764 may be formed of an inorganic material and/or an organic material.

When the light emitting material layer 740 includes the inorganic light emitting particles 100C (see FIG. 9D ), the electron transport layer 764 prevents interfacial defects with the light emitting material layer 740 to ensure stability when driving the device. ) may be made of an inorganic material. When the electron transport layer 764 is made of an inorganic material having excellent charge mobility, the transfer rate of electrons provided from the second electrode 730 may be improved, and since the electron concentration is large, the light emitting material layer 740 . electrons can be transported efficiently

In addition, when the light emitting material layer 740 includes the inorganic light emitting particles 100C, the energy level of the valence band (VB) of the inorganic light emitting particles 100C is very deep. In general, the HOMO energy level of the organic compound having electron transport properties is shallower than the valence band (VB) energy level of the inorganic light emitting particle. In this case, holes injected from the first electrode 710 into the light emitting material layer 740 including the inorganic light emitting particles 100C pass through the electron transport layer 764 made of an organic compound and leak to the second electrode 730 ( leakage) may occur.

Accordingly, in one exemplary embodiment, the electron transport layer 764 may be formed of an inorganic material having a relatively deep valence band (VB) energy level. Preferably, an inorganic material having a wide energy band gap (Eg) between the valence band (VB) energy level and the conduction band energy level may be used as the material of the electron transport layer 764 . In this case, holes injected into the light emitting material layer 740 including the inorganic light emitting particles 100C do not leak into the electron transport layer 764, and electrons provided from the second electrode 730 are efficiently transferred to the light emitting material layer ( 740).

In one exemplary embodiment, the electron transport layer 764 may be made of an inorganic material selected from the group consisting of metal oxide nanocrystals, semiconductor nanocrystals, nitrides, and combinations thereof. Preferably, the electron transport layer 764 may be formed of metal oxide nanocrystals.

Metal oxide nanocrystals applicable to the electron transport layer 764 include zinc (Zn), calcium (Ca), magnesium (Mg), titanium (Ti), tin (Sn), tungsten (W), tantalum (Ta), and hafnium. It may include an oxide of a metal selected from the group consisting of (Hf), aluminum (Al), zirconium (Zr), barium (Ba), and combinations thereof. More specifically, the metal oxide forming the electron transport layer 764 is titanium oxide (TiO ₂ ), zinc oxide (ZnO), zinc magnesium oxide (ZnMgO), zinc calcium oxide (ZnCaO), zirconium oxide (ZrO ₂ ), tin Oxide (SnO ₂ ), tin magnesium oxide (SnMgO), tungsten oxide (WO ₃ ), tantalum oxide (Ta ₂ O ₃ ), hafnium oxide (HfO ₃ ), aluminum oxide (Al ₂ O ₃ ), barium titanium oxide (BaTiO) ₃ ), barium zirconium oxide (BaZrO ₃ ), and combinations thereof, but the present invention is not limited thereto. The semiconductor nanocrystals applicable to the electron transport layer 764 include CdS, ZnSe, ZnS, and the like, and the nitride includes Si ₃ N ₄ , but is not limited thereto.

In one exemplary embodiment, the LUMO (or conduction band) energy level of the electron transport layer (ETL, 764) is designed to be similar to the LUMO energy level of the light emitting material layer (EML, 740), whereas the electron transport layer (ETL, 764) The HOMO (or valence band) energy level of may be designed to be deeper than the HOMO energy level of the light emitting material layer EML 740 . If necessary, the electron transport layer 764 may include an n-doped (n-dopant) component in the inorganic nanoparticles. The n-doped component that may be included in the electron transport layer 764 includes, but is not limited to, cations of metals composed of Al, Mg, In, Li, Ga, Cd, Cs, Cu, and the like, particularly trivalent cations. .

When the electron transport layer 764 is made of an organic material, the electron transport layer 764 is an oxazole-based compound, an isoxazole-based compound, a triazole-based compound, an isothiazole-based compound, an oxadiazole-based compound, a thiadiazole-based compound, or phenanthroline. )-based compound, perylene-based compound, benzoxazole-based compound, benzothiazole-based compound, benzimidazole-based compound, triazine-based compound, or an organic material such as an aluminum complex may be used.

Specifically, the organic material constituting the electron transport layer 764 is 3-(biphenyl-4-yl)-5-(4-tertbutylphenyl)-4-phenyl-4H-1,2,4-triazole (TAZ) , bathocuproine (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline; BCP), 2,2',2"-(1,3,5-Benzinetriyl)-tris(1-phenyl-1- H-benzimidazole)(TPBi), tris(8-hydroxyquinoline)aluminum(Alq ₃ ),bis(2-methyl-8-quninolinato)-4-phenylphenolatealuminum (III)(BAlq), bis(2-methyl-quinolinato)( tripnehylsiloxy) aluminum (III) (Salq) and a combination thereof may be selected from the group consisting of, but the present invention is not limited thereto.

In FIG. 8 , the second charge transfer layer 760 is illustrated as two layers of an electron injection layer 762 and an electron transport layer 764 . Optionally, the second charge transfer layer 760 may be formed of only one layer of the electron transport layer 764 . In addition, the second charge transfer layer 760 may be formed as one layer of the electron transport layer 764 in which cesium carbonate is blended with the electron transport material made of the aforementioned inorganic material.

On the other hand, when a hybrid charge transfer layer including the hole transport layer 754 constituting the first charge transfer layer 750 is made of an organic material and the second charge transfer layer 760 is made of an inorganic material is introduced, the light emitting diode (D) of the light emitting characteristics can be improved.

In an alternative embodiment, the lifetime of the device when holes migrate past the luminescent material layer 740 to the second electrode 730 , or electrons migrate past the luminescent material layer 740 to the first electrode 710 . and may lead to a decrease in efficiency. To prevent this, in the inorganic light emitting diode D, at least one exciton blocking layer may be positioned adjacent to the light emitting material layer 740 . For example, the inorganic light emitting diode D has an electron blocking layer (EBL, not shown) capable of controlling and preventing the movement of electrons between the hole transport layer 754 and the light emitting material layer 740 . can be located

For example, the electron blocking layer (not shown) is TCTA, tris[4-(diethylamino)phenyl]amine),N-(biphenyl-4-yl)-9,9-dimethyl-N-(4-(9) -Phenyl-9H-carbazol-3-yl)phenyl)-9H-fluoren-2-amine, tri-p-tolylamine, 1,1-bis(4-(N,N'-di(ptolyl)amino) phenyl)cyclohexane(TAPC), m-MTDATA, 1,3-bis(N-carbazolyl)benzene(mCP), 3,3'-bis(N-carbazolyl)-1,1'-biphenyl(mCBP), Poly- It may be made of TPD, CuPc, DNTPD and/or 1,3,5-tris[4-(diphenylamino)phenyl]benzene (TDAPB).

In addition, a hole blocking layer (HBL, not shown) as a second exciton blocking layer is positioned between the light emitting material layer 740 and the electron transport layer 764 , so that the light emitting material layer 740 and the electron transport layer 764 are located. ) to prevent the movement of holes between them. In an exemplary embodiment, as a material of the hole blocking layer (not shown), an oxazole-based compound, an isoxazole-based compound, a triazole-based compound, an isothiazole-based compound, an oxadiazole-based compound, a thiadizaol-based compound, and phenanthroline An organic material such as a (phenanthroline)-based compound, a perylene-based compound, a benzoxazole-based compound, a benzothiazole-based compound, a benzimidazole-based compound, a triazine-based compound, or an aluminum complex may be used. For example, the hole blocking layer (not shown) has a higher HOMO energy level than the material used for the light emitting material layer 740 is 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline. (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline; BCP), BAlq, Alq3, 2-biphenyl-4-yl-5-(4-t-butylphenyl)-1,3,4- oxadiazole (PBD), spiro-PBD and/or lithium quinolate (Liq), or the like.

A process for manufacturing the inorganic light emitting diode D3 shown in FIG. 8 will be described with reference to FIGS. 9A to 9D . First, as shown in FIG. 9D , a hole injection layer 752 and a hole transport layer 754 are sequentially formed on the upper surface of the first electrode 910 to form a first charge transfer layer 750 . The first charge transfer layer 750 including the hole injection layer 752 and the hole transport layer 754 is formed by a vacuum deposition process such as vacuum vapor deposition or sputtering, spin coating, drop coating, It may be formed by using a solution process such as dip coating, spray coating, roll coating, flow coating, casting process, screen printing or inkjet printing alone or in combination. . For example, the thickness of the hole injection layer 752 and the hole transport layer 754 may be 10 nm to 200 nm, preferably 10 nm to 100 nm, respectively, but the present invention is not limited thereto.

Next, as shown in FIG. 9B , a light emitting material layer 740 made of inorganic light emitting particles 100A is formed on the first charge transfer layer 750 . In order to form the light emitting material layer 740, a solution in which the inorganic light emitting particles 100 (see FIG. 1) are dispersed in a non-polar solvent and/or a polar solvent may be used. After a solution in which the inorganic light emitting particles 100 are dispersed is applied on the first charge transfer layer 750 , the light emitting material layer 740 is formed by volatilizing the solvent. In one exemplary embodiment, in order to form the light emitting material layer 740 including the inorganic light emitting particles 100, spin coating, drop coating, dip coating, spray coating, roll coating, flow coating, casting process, screen Solution processes such as printing or inkjet printing may be used alone or in combination. Then, the coated composition is thermally cured to volatilize the solvent to form the light emitting material layer 740 made of the inorganic light emitting particles 100A.

By the way, the inorganic light emitting particles 100A forming the light emitting material layer 740 react with a high temperature thermal curing process and external active oxygen and moisture, so that a significant portion of the organic ligands from among the organic ligands are freed (130b). It is lost, and only a portion of the organic ligand 130a binds to the surface of the shell 120 , thereby reducing stability. In addition, as the oxide film 150 is formed on the surface of the inorganic light emitting particle 100A or surface defects such as voids are caused, the luminous efficiency is reduced.

However, according to the present invention, the light emitting device having the first charge transfer layer 750 and the light emitting material layer 740 formed on the first electrode 710 is loaded into the vacuum chamber 220 (refer to FIG. 2A ), and firstly The heat treatment is performed under a high-vacuum condition, and the hydrothermal treatment is performed under a condition in which hydrogen ions converted by plasma treatment and a small amount of water vapor exist (see FIG. 2B ). High-vacuum heat treatment and hydrothermal treatment for the light emitting device on which the first charge transfer layer 750 and the light emitting material layer 740 are formed may be substantially the same as the heat treatment and hydrothermal treatment for the optical film 250 .

Accordingly, as shown in FIG. 7C , when the two-step heat treatment process is completed, the inorganic light-emitting particles 100C constituting the light-emitting material layer 740 are in a state in which the oxide film and surface defects are removed, and the two-step heat treatment process is performed. A plurality of organic ligands 130d are strongly bound to the surface of the shell 120 constituting the inorganic light-emitting particles 100C converted by the process, thereby stabilizing the inorganic light-emitting particles 100C. Since the exciton confinement effect and the quantum confinement effect are not reduced in the stabilized inorganic light emitting particle 100C, the luminous efficiency of the inorganic light emitting particle 100C may be improved.

Next, as shown in FIG. 9D , an electron transport layer 764 and an electron injection layer 762 are sequentially formed on the light emitting material layer 740 to form a second charge transfer layer 760 . The second charge transfer layer 760 including the electron injection layer 762 and/or the electron transport layer 764 is a vacuum deposition process such as vacuum vapor deposition or sputtering, spin coating, drop coating, dip coating, spray coating, It may be formed by a solution process such as roll coating, flow coating, casting process, screen printing or inkjet printing method alone or in combination. For example, the electron injection layer 762 and the electron transport layer 764 may be formed to have a thickness of 10 to 200 nm, preferably 10 to 100 nm, respectively.

Next, the inorganic light emitting diode D3 is manufactured by forming the second electrode 730 on the second charge transfer layer 760 using a deposition process.

Meanwhile, in FIGS. 9C and 9D , a high-vacuum heat treatment process and a hydrothermal treatment process are performed immediately after the light emitting material layer 740 is formed. Alternatively, the high-vacuum heat treatment process and the hydrothermal treatment process may be performed after the second charge transfer layer 760 is formed or after the second electrode 730 is formed.

Hereinafter, the present invention will be described through exemplary embodiments, but the present invention is not limited to the technical ideas described in the following examples.

Example: Preparation of light emitting film

A solution (organic solvent hexane) containing red quantum dots (InP/ZnSe/ZnS) to which organic ligands such as oleylamine, trioctylphosphine, and dodecanethiol are bound on one surface of a substrate made of an acrylate-based resin is coated and A light emitting film in the form of a thin film (thickness of 10 µm) was prepared by thermal curing at a temperature of 230°C for 30 minutes. The light emitting film in the form of a thin film was loaded into a CVD chamber, ^{a high-vacuum of 1X10 -4} torr was introduced into the CVD chamber, and a first heat treatment was performed at a temperature of 230°C for 1 hour. Then, the plasma-treated hydrogen ions are diluted with a carrier gas and supplied to the CVD chamber, and while supplying water vapor to the CVD chamber so as to be 30 ppmv based on the total gas in the CVD chamber (total gas is 500 sccm, hydrogen ions are supplied at a flow rate of 10 sccm), hydrothermal treatment at a temperature of 200° C. for 20 minutes, to finally prepare a light emitting film made of quantum dots.

Comparative Example: Light-emitting film production

Instead of the hydrothermal treatment step, the same materials and procedures as in Example were repeated to prepare a light emitting film, except that the secondary heat treatment process was performed in a state in which water vapor was not supplied.

Experimental Example 1: EQE, Wp, FWHM evaluation of quantum dots

External quantum efficiency (EQE, %), peak emission wavelength (Wp, nm) and full width at half maximum (FWHM, nm) of quantum dots obtained before and after each step in Examples and Comparative Examples ) was evaluated. The evaluation results of quantum dots for each quantum dot (initial sample) before coating and thermal curing treatment (initial sample), quantum dots after thermal curing, quantum dots after the first heat treatment process, and quantum dots after the secondary hydrothermal treatment process are shown in Table 1 below. As shown in Table 1, the EQE of the quantum dots finally prepared in Comparative Example without hydrothermal treatment was only 82.8% compared to the initial quantum dots. On the other hand, the EQE of the quantum dots finally prepared in Examples was 96.4% compared to the initial quantum dots, and the luminous efficiency of the quantum dots was largely recovered through two different heat treatments.

Changes in EQE, Wp and FWHM of quantum dots Sample before curing after curing After vacuum heat treatment After hydrothermal treatment*
Example EQE (%) 33.1 26.8 27.6 31.9 EQE retention (%) 100 81.0 83.4 96.4 Wp (nm) 641 643 642 641 FWHM (nm) 38 39 38 38
comparative example EQE (%) 33.2 26.3 27.1 27.5 EQE retention (%) 100 79.2 81.6 82.8 Wp (nm) 641 642 642 641 FWHM (nm) 38 38 38 38 *: In the comparative example, heat treatment proceeded without introducing steam

Experimental Example 2: Measurement of shape change of quantum dots

The shape of quantum dots constituting the light emitting film prepared in Examples was measured using an electron microscope (TEM) before and after each process step. The measurement results are shown in Fig. 10a (initial quantum dots before coating and thermal curing), Fig. 10b (quantum dots after thermal curing), Fig. 10c (quantum dots after primary heat treatment), and Fig. 10d (quantum dots after hydrothermal treatment). The initial quantum dots had a very thin oxide film and a small amount of surface defects, and existed in a relatively uniform crystalline state (FIG. 10a). After the thermal curing process, exposed to high temperature and exposed to external active oxygen and moisture, an oxide film was formed and a number of surface defects were present (FIG. 10b). After the first high-vacuum heat treatment, as active oxygen molecules and hydrogen molecules of moisture were removed, the bond of the oxide film formed on the quantum dot surface was dissociated and removed, but by-products and some surface defects were still present (FIG. 10c). On the other hand, after the hydrothermal treatment, the dissociated oxide film is completely removed, the surface defects are completely removed by the hydrothermal treatment, the molecules forming the core and the shell are rearranged, and the by-products are also completely removed, resulting in a uniform and highly crystalline state. It was recovered as quantum dots (Fig. 10d).

Experimental Example 3: Evaluation of binding force of organic ligands

The initial state of the quantum dots constituting the light emitting film prepared in Examples and the binding force of the organic ligand bound to the surface of the quantum dots after hydrothermal treatment was evaluated.

First, EGA-MS analysis was performed on each sample. In order to perform the EGA-MS analysis, the temperature was increased to a maximum of 800°C by starting at 50°C and increasing by 20°C at intervals of 20 minutes. Interface temperature, inlet temperature, and oven temperature were each set to 300 °C, and an EGA column was used as the column. The source temperature was 230° C., and He was used as the carrier gas. The results of EGA-MS analysis of the initial quantum dot sample are shown in FIG. 11A, and the results of EGA-MS analysis of the quantum dot sample after hydrothermal treatment are shown in FIG. 11B. As shown in FIG. 11a , organic ligands with weak binding force among the initial quantum dots were decomposed and separated from the quantum dots while the binding force with the quantum dots was dissociated at a temperature of 200° C. or less. In particular, in the initial quantum dot sample, it was confirmed that there are a number of organic ligands that are dissociated from binding to quantum dots at temperatures of 86°C and 178°C.

On the other hand, as shown in FIG. 11b, organic ligands, which are dissociated from bonding with quantum dots at temperatures of 86°C and 178°C in the initial quantum dot sample, are all removed together with impurities or defective molecules such as carbon-based by-products by hydrothermal treatment. , there was no organic ligand decomposed at 213°C or lower. This is interpreted that the luminous efficiency of the quantum dots is recovered while the organic ligands having excellent binding force to the quantum dots are selectively strongly bound to the quantum dots through high-vacuum heat treatment and hydrothermal treatment.

GC-MS analysis was performed on the same sample. To perform GC-MS analysis, the inlet temperature was set at 280°C, the column was HP-5, and the source temperature was set at 230°C. The carrier gas was He, the solvent was toluene, and the concentration was set to 1%. The GC-MS analysis result of the initial sample is shown in FIG. 12A, and the GC-MS analysis result of the sample after hydrothermal treatment is shown in FIG. 12B. In addition, the estimated component analysis results for each peak detected according to the retention time are shown in Table 2. As shown in FIG. 12A , the initial quantum dot sample contains a plurality of organic ligands with weak binding force that escape from the quantum dots at a temperature of 200° C. or less (86° C./178° C.). On the other hand, as shown in FIG. 12b , in the quantum dot sample subjected to high-vacuum heat treatment and hydrothermal treatment, most of the organic ligands with weak binding force and byproducts such as residual impurities were removed from the surface of the quantum dot. These results indicate that the quantum dot sample has improved luminous efficiency while selectively binding only ligands (l-dodecanethiol, dodecyl sulfide, 1-(dodecyldisulfanyl)dodecane) with excellent binding to the quantum dot surface to the quantum dot sample after hydrothermal treatment. do.

GC-MS analysis of quantum dots Residence time (RT) putative component 10.2 tetrahydro-2H-pyran-2-on (presumed solvent) 11.68 2-oxepanone (presumed solvent) 16.56 2,5,8,11-tetraoxatridecan-13-ol 17.13/17.15 1-dodeanethiol 19.77/22.52 2,5,8,11,14-pentaoxahexadecan-16-ol 24.94 2-[2-[2-[2-[2-[2-[2-[2-[2-(2-Methoxyethoxy)ethoxy]ethoxy]ethoxy]ethoxy]ethoxy]ethox 27.34 2-[2-[2-[2-[2-[2-[2-[2-[2-(2-Methoxyethoxy)ethoxy]ethoxy]ethoxy]ethoxy]ethoxy]ethanol 28.29 dodecyl sulfide 30.44 2-[2-[2-[2-[2-[2-[2-[2-[2-(2-Methoxyethoxy)ethoxy]ethoxy]ethoxy]ethoxy]ethoxy]ethox 31.34/31.35 1-(dodecyldisulfanyl)dodecane

In the above, the present invention has been described based on exemplary embodiments and examples of the present invention, but the present invention is not limited to the technical ideas described in the above embodiments and examples. Rather, those skilled in the art to which the present invention pertains can easily propose various modifications and changes based on the above-described embodiments and examples. However, it is clear from the appended claims that all such modifications and variations are within the scope of the present invention.

100, 100A, 100B, 100C: inorganic light emitting particles
110: core
120: shell
130, 130a, 130b, 130c, 130d: organic ligands
210: vacuum chamber
220: vacuum pump
230: micro plasma processing unit
240: water vapor supply unit
250: light emitting film
300, 500: light emitting display device
310, 510: substrate
380, 580: color conversion layer
710: first electrode
720: light emitting layer
730: second electrode
740: light emitting material layer
D, D1, D2: light emitting diode
Tr: thin film transistor

Claims (13)

Preparing a light emitting film made of inorganic light emitting particles;
loading the light emitting film into a chamber, and performing thermal annealing in a vacuum atmosphere and a temperature of 180 to 230°C; and
and performing hydro thermal annealing in the chamber loaded with the heat-treated light emitting film.
preparing an array panel;
disposing a color conversion layer made of inorganic light emitting particles on the array panel;
loading the array panel on which the color conversion layer is disposed into a chamber, and performing heat treatment in a vacuum atmosphere and a temperature of 180 to 230°C; and
and performing hydrothermal treatment in the chamber in which the array panel on which the heat-treated color conversion layer is disposed is loaded.
forming a first charge transfer layer on the first electrode;
forming a light emitting material layer including inorganic light emitting particles on the first charge transfer layer;
loading the thin film on which the light emitting material layer is formed into a chamber, and performing heat treatment in a vacuum atmosphere and a temperature of 180 to 230°C; and
Method of manufacturing an inorganic light emitting diode comprising the step of performing a hydrothermal treatment in the chamber in which the heat-treated thin film is loaded.
The method according to any one of claims 1 to 3, wherein the performing the heat treatment is performed under vacuum conditions ranging ^{from 1 X 10 -3} torr to 1 X 10 ^{-4 torr.}
The method according to any one of claims 1 to 3, wherein performing the hydrothermal treatment is performed at a temperature of 180 to 230°C in the presence of water vapor and hydrogen ions.
The method according to any one of claims 1 to 3, wherein in the step of performing the hydrothermal treatment, the amount of water vapor is 10 to 50 ppmv (parts per million volume) based on the volume of the total gas supplied to the vacuum chamber. A method in which hydrogen ions formed by plasma treatment are supplied at a flow rate of 10 to 200 sccm (standard cubic centimeter per minute).
The method according to any one of claims 1 to 3, wherein the inorganic light emitting particles are quantum dots or quantum rods.
The method of claim 2 , wherein the array panel includes a substrate, a thin film transistor disposed on the substrate, and a light emitting diode disposed on the substrate and electrically connected to the thin film transistor.
The method of claim 8 , wherein the light emitting diode includes a first electrode, a second electrode facing the second electrode, and a light emitting material layer positioned between the first electrode and the second electrode.
10. The method of claim 9, wherein the light emitting diode emits white (W) light.
9. The method of claim 8, wherein the light emitting diode comprises a micro light emitting diode.
The method of claim 11 , wherein the micro light emitting diode emits light in a blue (B) wavelength band.
4. The method of claim 3, wherein after the forming of the light emitting material layer, forming a second charge transfer layer on the light emitting material layer and forming a second electrode on the second charge transfer layer How to include.

Images