KR102535149B1 - Organic inorganic hybrid light emitting partilce, light emitting flim, led package, light emitting diode and display device having the same - Google Patents

Abstract

The present invention relates to light emitting particles composed of a quantum dot core having an alloy structure in which a perovskite component and a metal halide component are mixed, and a silicon-based shell surrounding the quantum dot core. The light-emitting particles of the present invention are made of environmentally friendly materials and have excellent light-emitting properties and structural stability. Therefore, the light-emitting particles according to the present invention can be applied to light-emitting films, LED packages, quantum dot light-emitting diodes, and display devices requiring excellent light-emitting properties.

Description

Light emitting particles, light emitting film, LED package including the same, light emitting diode and display device

The present invention relates to a light emitting material, and more particularly, to light emitting particles having improved light emitting efficiency, a light emitting film including the light emitting particles, an LED package, a light emitting diode, and a display device.

As the information age progresses, a display field that processes and displays a large amount of information is rapidly developing. In response to this, a liquid crystal display device (LCD), a plasma display panel device (PDP), a field emission display device (FED), and an organic light emitting diode display device Various flat panel display devices such as a diode display device (OLED) have been developed and are in the spotlight.

Among flat panel display devices, the organic light emitting diode display device is used as a next-generation display device that can replace a liquid crystal display device because of its thin structure and low power consumption. However, when the current density of the light emitting diode is increased or the driving voltage is increased in order to increase the light emitting luminance in the organic light emitting diode display device, the lifetime of the light emitting diode is shortened due to deterioration such as decomposition of the organic light emitting material used in the organic light emitting diode. There is a problem with shortening.

Recently, efforts have been made to use quantum dots (QDs) in display devices. Quantum dots emit light as electrons in an unstable state descend from the conduction band to the valence band. Quantum dots generate strong fluorescence because they have a very large extinction coefficient and excellent quantum yield. In addition, since the emission wavelength is changed according to the size of the quantum dots, by adjusting the size of the quantum dots, light in the entire visible light range can be obtained, so that various colors can be implemented.

Inorganic materials conventionally used as quantum dot materials contain lead (Pb), which is harmful to the human body and is not good for the environment, so there are many restrictions on their use. On the other hand, when cadmium selenide (CdSe) used as the core of quantum dots having a core-shell structure is used in the form of a film, its luminous properties such as quantum efficiency and/or luminance are rapidly lowered, and cadmium (Cd) is also toxic. Because of this, it is expected that there will be many restrictions on its use. Therefore, continuous research is required on an environmentally friendly light emitting material having excellent light emitting properties and a stable crystal structure.

An object of the present invention is to provide light emitting particles having excellent light emitting efficiency and improved structural stability, a light emitting film including the light emitting particles, an LED package, a light emitting diode, and a display device.

Another object of the present invention is to provide environmentally friendly light emitting particles that are harmless to the human body and the environment, a light emitting film including the light emitting particles, an LED package, a light emitting diode, and a display device.

According to one aspect of the present invention, the present invention includes a quantum dot core having an alloy structure in which a perovskite component and a metal halide component are mixed, and a shell surrounding the quantum dot core and made of a silicon-based, for example, amorphous silicon-based material It provides light-emitting particles that do.

For example, the quantum dot core may be represented by Chemical Formula 1 below.

Formula 1

[ABX ₃ ] _a [BX ₂ ] _1-a

(In Formula 1, A is organoammonium or alkali metal, B is selected from the group consisting of tin (Sn) or germanium (Ge) group 4A metal, divalent transition metal, alkaline earth metal, and combinations thereof, X Is selected from the group consisting of Cl, Br, I and combinations thereof, a represents the mole fraction of [ABX ₃ ] component, 0 < a < 1)

According to another aspect of the present invention, the present invention provides a light emitting film including the light emitting particles, an LED package, and a liquid crystal display device including the light emitting film and/or the LED package.

According to another aspect of the present invention, the present invention provides a quantum dot light emitting diode in which the light emitting particles are included in a light emitting material layer and a quantum dot light emitting display device including the quantum dot light emitting diode.

The present invention includes a quantum dot core having a perovskite component and a metal halide component having an alloy structure, and a silicon-based shell surrounding the quantum dot core and having a wider energy band gap than the quantum dot core We propose a luminescent particle that

The light-emitting particles of the present invention are environmentally friendly because they do not contain components harmful to the human body such as lead, and the energy band gap of the core can be adjusted by adjusting the mixing ratio between components constituting the core.

In addition, luminous efficiency can be maximized by using a silicon-based shell having a wider energy band gap than the core. In particular, the shell may be made of an amorphous material, and in this case, it is possible to form light-emitting particles having a size larger than that of the quantum dot core. By adjusting the thickness of the shell and changing the size of the light emitting particles, there is an advantage in efficiently implementing various colors.

In addition, since the distance between quantum dot cores having an alloy structure that functions as a main light emitting body using a shell increases, the fluorescence resonance energy transfer (FRET) phenomenon caused by the decrease in distance between adjacent quantum dots is prevented, thereby reducing quantum efficiency. there is no

In addition, since the quantum dot core does not contain lead (Pb) or cadmium (Cd) components harmful to the human body and the environment, the light emitting particle of the present invention is an environmentally friendly material.

The light-emitting particles of the present invention, which have improved light-emitting efficiency and can implement various colors, can be applied to a light-emitting film of a display device, an LED package, a light-emitting diode, and the like.

1 is a diagram schematically illustrating one form of light-emitting particles according to an exemplary embodiment of the present invention.
2 is a diagram schematically illustrating one form of light-emitting particles according to another exemplary embodiment of the present invention.
3 is a cross-sectional view schematically showing the structure of a light-emitting film including light-emitting particles according to an exemplary embodiment of the present invention.
4 is a schematic cross-sectional view of a display device including a light-emitting film to which light-emitting particles are applied according to an exemplary embodiment of the present invention.
5 is a schematic cross-sectional view of a display panel constituting a display device according to an exemplary embodiment of the present invention. '
6 is a schematic cross-sectional view of an LED package to which light-emitting particles are applied according to an exemplary embodiment of the present invention.
7 and 8 are cross-sectional views schematically illustrating a quantum dot light emitting diode in which light emitting particles are applied to a light emitting material layer according to an exemplary embodiment of the present invention.
9 is a cross-sectional view schematically illustrating a quantum dot light emitting display device to which a quantum dot light emitting diode according to an exemplary embodiment of the present invention is applied.
10 is a diagram schematically illustrating an energy band diagram of a core and a shell of a light emitting particle synthesized according to an exemplary embodiment of the present invention.
11 is a photograph of a state in which light emitting particles synthesized according to an exemplary embodiment of the present invention emit light.
12 is a diagram schematically showing energy band diagrams of cores and shells of light-emitting particles synthesized according to an exemplary embodiment of the present invention.
13 is a photograph of a state in which light emitting particles synthesized according to an exemplary embodiment of the present invention emit light.
14 is a TEM (transmission electron microscopy) picture of light-emitting particles synthesized according to an exemplary embodiment of the present invention.
15 is a graph showing X-ray diffraction (XRD) analysis results for light-emitting particles synthesized according to an exemplary embodiment of the present invention.
16A is a graph showing absorption spectrum analysis results for light-emitting particles synthesized according to an exemplary embodiment of the present invention.
16B and 16C are graphs showing emission spectrum analysis results of light-emitting particles synthesized according to an exemplary embodiment of the present invention, respectively.

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

[luminescent particles]

The light emitting particle of the present invention consists of a quantum dot core of an alloy structure composed of a component having a perovskite structure and a metal halide component, and a shell made of a silicon-based material surrounding the quantum dot core .

The quantum dot core having an alloy structure can be divided into a homogeneous alloy structure and a gradient alloy structure. FIG. 1 is a light emitting particle composed of a quantum dot core and a shell having a homogeneous alloy structure is shown schematically. As shown in FIG. 1, the light emitting particle 100A according to the first exemplary embodiment of the present invention includes a quantum dot core 110a having a homogeneous alloy structure and a shell of a silicon-based material surrounding the quantum dot core 110a ( shell).

In the quantum dot core 110a, a quantum dot material having a perovskite structure represented by [ABX ₃ ] and a metal halide component represented by [BX] are uniformly mixed over the entire region. Accordingly, the quantum dot core 110a may be represented by Chemical Formula 1 throughout the entire region.

Formula 1

[ABX ₃ ] _a [BX ₂ ] _1-a

(In Formula 1, A is organoammonium or alkali metal, B is selected from the group consisting of tin (Sn) or germanium (Ge) group 4A metal, divalent transition metal, alkaline earth metal, and combinations thereof, X is selected from the group consisting of Cl, Br, I and combinations thereof, and a represents the mole fraction of the [ABX ₃ ] component, 0 < a < 1)

There is an advantage in that various colors can be easily expressed by adjusting the composition and mixing ratio of halogen (X) atoms constituting the perovskite component constituting the quantum dot core 110a. In addition, unlike other quantum dot cores, since the perovskite structure has a stable lattice structure, the quantum dot core 110a of the present invention containing the perovskite component has a very stable crystal structure and has high luminous efficiency. can be improved

Among the perovskite components constituting the quantum dot core 110a, when A is an alkali metal such as sodium (Na), potassium (K), rubidium (Rb), cesium (Cs) or francium (Fr), an inorganic metal halide It constitutes a perovskite, and when A is an alkylammonium component, it constitutes an organic-inorganic hybrid perovskite. In one exemplary embodiment, A constituting the quantum dot core 100a may be an unsubstituted or fluorine-substituted C1-C10 alkylammonium component. More specifically, A may be methyl ammonium (MA) or ethyl ammonium (EA). In this case, the quantum dot core 100a may form an organic-inorganic hybrid quantum dot core containing organic-inorganic hybrid perovskite.

For example, when the quantum dot core 110a includes organic-inorganic hybrid perovskite, the organic-inorganic hybrid perovskite has a layered structure in which inorganic planes on which metal cations are located are sandwiched between organic planes on which organic cations are located. have At this time, since the difference in permittivity between the organic material and the inorganic material is large, the excitons are confined within the inorganic plane constituting the organic-inorganic hybrid perovskite lattice structure, and thus have the advantage of emitting light having high color purity.

On the other hand, B is a metal cation component, preferably a metal component that is not a component harmful to the human body and/or environment such as lead (Pb) or cadmium (Cd). In one exemplary embodiment, B may be a Group 4A metal component such as Sn or Ge. X is an anionic component and is a halogen element selected from the group consisting of Cl, Br, I and combinations thereof.

As shown in Formula 1, the quantum dot core 100a according to the present invention includes a metal halide component [BX ₂ ] in addition to the perovskite component [ABX ₃ ]. That is, the quantum dot core 100a of the present invention is a quantum dot core having an alloy structure in which a perovskite component and a metal halide component are mixed. At this time, the emission wavelength of the quantum dot core 100a can be easily changed by adjusting the composition or mixing ratio of the halogen component.

In doped quantum dots, the band gap of the main material does not change and an energy level according to the doped impurity is formed between the band gaps of the main material. In contrast, in the case of the quantum dot core 110a having an alloy structure according to the present invention, by changing the composition of perovskite [ABX ₃ ] and metal halide [BX ₂ ] constituting the quantum dot core 110a, the entire quantum dot The energy band gap of the core 110a may be adjusted. That is, if a material with a relatively large band gap is included in a large amount, the band gap of the quantum dot core 110a having an alloy structure may also increase, and conversely, if a material with a relatively small band gap is included in a large amount, A band gap of the quantum dot core 110a having an alloy structure may decrease.

In other words, in the case of conventional quantum dots, the energy bandgap is changed according to the size of the quantum dots to emit light of different wavelengths. However, the quantum dot core 110a of the present invention emits light in various wavelengths by adjusting the composition of the halogen component constituting the perovskite, the composition ratio of the perovskite and the metal halide component, and the composition or combination of the halogen component. It is possible to synthesize a quantum dot core 110a.

Hereinafter, in the present specification, when referring to a component constituting the quantum dot core 110a, it may be abbreviated as [ABX ₃ ], which is a perovskite component used as a main component. For example, although the quantum dot core synthesized in an exemplary embodiment of the present invention is sometimes expressed as CH ₃ NH ₃ SnBr ₃ , etc., the actual quantum dot core has an alloy structure in which a perovskite component and a metal halide component are mixed. It means a quantum dot core having

In one exemplary embodiment, the quantum dot core 110a having an alloy structure in which a perovskite component and a metal halide component are mixed may have a size of 10 to 1000 nm, preferably 100 to 500 nm, , the present invention is not limited thereto. In addition, [ABX ₃ ], a perovskite component constituting the quantum dot core 110a, and [BX ₂ ], a metal halide component, may be mixed in a molar ratio of 1:1 to 5:1.

A shell 120 made of a silicon-based material surrounds the outer side of the quantum dot core 110a having an alloy structure in which a perovskite component and a metal halide component are mixed. In an exemplary embodiment, the shell 120 forms a type I core-shell having a larger bandgap than the quantum dot core 110a. In the case of the type I structure, the band gap of the quantum dot core 110a is located between the band gap of the shell 120, and the electrons and holes present in the quantum dot core 110a and the shell 120 form the quantum dot core 110a. get trapped inside Accordingly, compared to the case where only the quantum dot core 110a exists, the rate at which recombination of electrons and holes occurs increases, thereby increasing quantum efficiency.

In addition, the shell 120 protects the surface of the quantum dot core 110a, which is the main light emitting material. By forming the shell 120, it is possible to reduce photodegradation caused by penetration of materials such as water or oxygen and reduce sensitivity to external environments. In addition, when the shell 120 is applied, the trap energy level on the surface of the quantum dot core 110a is reduced, thereby reducing the effect of the trap. For example, the shell 120 may be made of an insulating material such as silica (SiO ₂ ) or silicon nitride (SiNx), but the present invention is not limited thereto.

Meanwhile, in one exemplary embodiment, the silicon-based material constituting the shell 120 may be made of an amorphous material. In the case of forming the shell 120 using an amorphous material according to the present invention, the size of the light-emitting particles 100A including the shell 120 may be larger than that of the quantum dot core 110a. By adjusting the thickness of the shell 120, there is an advantage in that the light emitting particles 100A including the quantum dot core 110a can emit light in various wavelength bands and implement various colors.

In addition, when the size of the light emitting particle 100A is larger than the size of the quantum dot core 120a by forming the shell 120, the distance between the quantum dot cores 120a of adjacent light emitting particles increases. Therefore, when using a plurality of light emitting particles 100A as a light emitting film, etc., fluorescence resonance energy transfer generated by a decrease in the distance between quantum dot cores 110a constituting adjacent light emitting particles 100A (Fluorescence Resonance Energy Transfer; FRET) phenomenon can be prevented to solve the problem of quantum efficiency deterioration.

Meanwhile, FIG. 2 shows a light emitting material 100B composed of a quantum dot core 110b having a hardness alloy structure and a silicon-based shell 120 surrounding the quantum dot core 110b according to another exemplary embodiment of the present invention. . In the uniform quantum dot core 110a shown in FIG. 1 , the perovskite component [ABX ₃ ] and the metal halide component [BX ₂ ] are uniformly mixed over the entire area of the quantum dot core 110a. Unlike this, in the quantum dot core 110b having a hardness alloy structure, a region rich in [ABX ₃ ], a perovskite component, and a region rich in [BX ₂ ], a metal halide component, are separated. As an example, in FIG. 2, the [ABX ₃ ] component, which is a perovskite component, is intensively disposed in the central region of the quantum dot core 110b, and the [BX ₂ ] component, which is a metal halide component, is intensively disposed in the peripheral region of the quantum dot core 110b. However, the shape of the quantum dot core having a hardness alloy structure according to the present invention is not limited thereto.

On the other hand, in FIGS. 1 and 2, a structure in which the shell 120 is surrounded by one quantum dot core 110a, 110b having one alloy structure is illustrated, but two or more in one shell 120, one example As a result, about 2 to 10 quantum dot cores 110a and 110b may be mixed together.

As such, the light emitting particles according to the present invention can implement light emission in various wavelength bands by changing the composition ratio of components constituting the quantum dot core capable of a stable crystal structure or by adjusting the thickness of the shell. In addition, the quantum efficiency can be doubled by forming a shell surrounding the quantum dot core, the photodegradation phenomenon caused by the influence of oxygen or moisture can be prevented, and the FRET phenomenon can be prevented by increasing the thickness of the shell.

[Light emitting film, LED package and display device]

As described above, the light-emitting particles according to the present invention can exhibit excellent light-emitting efficiency, implement various colors, and prevent photodegradation or FRET. The light-emitting particles according to the present invention can be applied to a display device requiring light emission. In this embodiment, a case in which the light-emitting particles are applied to a light-emitting film, an LED package, and a display device including them will be described.

3 is a schematic cross-sectional view of a light emitting film according to an exemplary embodiment of the present invention. As shown in FIG. 3 , the light emitting film 200 is composed of a quantum dot core 110 and a shell 120 made of a silicon-based material surrounding the quantum dot core 110, and the light emitting particles 100 are layered. The quantum dot core 110 has an alloy structure in which a perovskite component and a metal halide component are mixed, and the shell 120 is made of an amorphous silicon-based material having a band gap greater than that of the quantum dot core 110.

Various colors can be easily implemented by adjusting the content of the perovskite component and the metal halide component constituting the quantum dot core 110 or by adjusting the type of halogen, which is an anion component constituting the perovskite. . In particular, when the quantum dot core 110 includes organic-inorganic hybrid perovskite, it may have a stable crystal structure and produce light-emitting particles having excellent color purity. In addition, a trap energy level may be reduced by protecting the quantum dot core 110 using the shell 120 . In particular, by using the shell 120 made of amorphous silicon-based material, the thickness of the shell 120 is freely adjusted to emit light in various wavelength bands, and at the same time, the FRET phenomenon that can be caused by the decrease in the distance between the quantum dot cores 110 It can be minimized to maximize the luminous efficiency.

Meanwhile, although not illustrated, the light emitting film 200 may include nanorods in addition to the light emitting particles 100 . In this case, the nanorods may be made of a semiconductor compound and may have an energy bandgap larger than the energy bandgap of the quantum dot core 110 and smaller than the energy bandgap of the shell 120 . The nanorods (not shown) may absorb light from a light source and transfer energy to the light emitting particles 100 to increase quantum efficiency of the light emitting particles 100 and improve luminance of the light emitting film 200 .

At this time, when the energy bandgap of the nanorods (not shown) is smaller than the energy bandgap of the quantum dot core 110, the energy absorbed by the nanorods (not shown) may not be transmitted to the quantum dot core 110, When the energy bandgap of the nanorods is greater than the energy bandgap of the shell 120 , energy absorbed by the nanorods may be simultaneously transferred to the quantum dot core 110 and the shell 120 .

The nanorods (not shown) may be made of any one of ZnSe, SnSeS, ZnO, GaP, and GaN, and may be included in the light emitting film 200 in an amount of about 5 to 30% by weight. For example, nanorods (not shown) may absorb light of a short wavelength (eg, 430 to 470 nm).

Subsequently, a display device to which the light emitting film according to the present invention is applied will be described. FIG. 4 is a schematic cross-sectional view of a liquid crystal display device including a light emitting film according to an exemplary embodiment of the present invention, and FIG. 5 is a schematic cross-sectional view of the liquid crystal panel of FIG. 4 .

As shown in FIG. 4 , a liquid crystal display device 400 according to an exemplary embodiment of the present invention includes a liquid crystal panel 410, a backlight unit 470 positioned under the liquid crystal panel 410, and a liquid crystal panel 410 and the light emitting film 300 positioned between the backlight unit 460 .

Referring to FIG. 5 , the liquid crystal panel 410 is interposed between the first and second substrates 420 and 450 and the first and second substrates 420 and 450 facing each other and contains liquid crystal molecules 462. A liquid crystal layer 460 including

A gate electrode 422 is formed on the first substrate 420 , and a gate insulating layer 424 is formed covering the gate electrode 422 . In addition, a gate line (not shown) connected to the gate electrode 422 is formed on the first substrate 420 .

A semiconductor layer 426 is formed on the gate insulating film 424 to correspond to the gate electrode 422 . The semiconductor layer 426 may be made of an oxide semiconductor material. Meanwhile, the semiconductor layer 426 may include an active layer made of amorphous silicon and an ohmic contact layer made of impurity amorphous silicon.

A source electrode 430 and a drain electrode 432 spaced apart from each other are formed on the semiconductor layer 426 . In addition, a data line (not shown) connected to the source electrode 430 intersects the gate line to define a pixel area. The gate electrode 422, the semiconductor layer 426, the source electrode 430, and the drain electrode 432 constitute a thin film transistor Tr.

A protective layer 434 having a drain contact hole 436 exposing the drain electrode 432 is formed on the thin film transistor Tr. On the protective layer 434, a pixel electrode 440 as a first electrode connected to the drain electrode 432 through a drain contact hole 436 and a common electrode as a second electrode alternately arranged with the pixel electrode 440 (442) is formed.

Meanwhile, a black matrix 454 is formed on the second substrate 450 to cover non-display areas such as the thin film transistors Tr, gate wires, and data wires. In addition, a color filter layer 456 is formed corresponding to the pixel area.

The first and second substrates 420 and 450 are bonded with the liquid crystal layer 460 interposed therebetween, and the liquid crystal molecules of the liquid crystal layer 460 are moved by an electric field generated between the pixel electrode 440 and the common electrode 442. 462 is driven. Although not shown, an alignment film may be formed on each of the first and second substrates 412 and 450 in contact with the liquid crystal layer 460, and an alignment film may be formed on the outer side of each of the first and second substrates 412 and 450, respectively. A polarizing plate having a vertical transmission axis may be attached.

Referring back to FIG. 4 , the backlight unit 470 includes a light source (not shown) and supplies light to the liquid crystal panel 410 . The backlight unit 470 may be classified into a direct type and a side type according to the position of the light source.

When the backlight unit 470 is a direct type, the backlight unit includes a bottom frame (not shown) surrounding the lower portion of the liquid crystal panel 410, and a plurality of light sources may be arranged on a horizontal surface of the bottom frame. Meanwhile, when the backlight unit 470 is a side type, the backlight unit 470 includes a bottom frame (not shown) surrounding the lower part of the liquid crystal panel 410, and a light guide plate (not shown) on a horizontal surface of the bottom frame. ) is disposed, and the light source may be disposed on at least one side of the light guide plate. At this time, the light source may emit light of a blue wavelength, for example, a wavelength range of about 430 to 470 nm.

The light emitting film 300 is positioned between the liquid crystal panel 410 and the backlight unit 470 and improves color purity of light provided from the backlight unit 470 . For example, the light emitting film 300 surrounds the quantum dot core 110 having an alloy structure in which a perovskite component and a metal halide component are mixed, and surrounds the quantum dot core 110, for example, made of an amorphous silicon-based material shell 120. For example, the quantum dot core 110 may emit light of a red wavelength band or a green wavelength band.

As described above, the light-emitting particle 100 according to the present invention can implement light emission in various wavelength bands by changing the composition ratio of components constituting the quantum dot core capable of a stable crystal structure or by adjusting the thickness of the shell. In addition, the quantum efficiency can be doubled by forming a shell surrounding the quantum dot core, the photodegradation phenomenon caused by the influence of oxygen or moisture can be prevented, and the FRET phenomenon can be prevented by increasing the thickness of the shell. Accordingly, the light emission luminance of the liquid crystal display device 400 including the light emitting film 300 increases.

Subsequently, an LED package to which the light emitting particles according to the present invention can be applied will be described. 6 is a schematic cross-sectional view of an LED package according to an exemplary embodiment of the present invention.

As shown in FIG. 6 , the LED package 500 includes an LED chip 510 and an encapsulation part 520 covering the LED chip 510 . A quantum dot core (110, see FIG. 3) in which a perovskite component and a metal halide component are combined in the encapsulation 520, and a shell (120, see FIG. 3) surrounding the quantum dot core and made of, for example, an amorphous silicon-based material The light emitting particles 100 made of are included as phosphors. The encapsulation part 520 may also include an encapsulation resin (not shown) capable of dispersing the light emitting particles 100 . For example, the light emitting particles 100 may be dispersed by an encapsulating resin (not shown) having good heat dissipation characteristics such as a silicon-based resin and/or an epoxy-based resin.

In one exemplary embodiment, the LED package 500 may be a white LED package that can emit white light. One method for realizing white light is to use an LED chip 510 capable of emitting ultraviolet light as a light source, and to emit red (R), green (G), and blue (B) light within the encapsulation portion 520. The light-emitting particles 100 of the invention can be combined. Another method for implementing white light is, for example, a method of using an LED chip 510 emitting blue light and combining yellow, green, and/or red light emitting particles 100 capable of absorbing blue light. It can be.

For example, the LED chip 510 may be a blue LED chip emitting light of about 430 to 470 nm wavelength, and the light emitting particles 100 may be a phosphor emitting light of a green wavelength band and/or a red wavelength band. In one exemplary embodiment, the blue LED chip 510 uses sapphire as a substrate, and a material having a blue peak wavelength may be applied as a light source for excitation. For example, the material constituting ^the blue light emitting diode chip may be selected from ^the group consisting of GaN, InGaN, InGaN/GaN, BaMgAl ₁₀ O ₇ :Eu ²⁺ , CaMgSi ₂ O ₆ :Eu ²⁺ and combinations thereof. , the present invention is by no means limited thereto.

In addition, the LED package 500 has a case 530 and first and second wires connected to the LED chip 510 through first and second wires 552 and 554 and exposed to the outside of the case 530. Electrode leads 542 and 544 may be further included.

The case 530 includes a body 532 and a side wall 534 protruding from the upper surface of the body 532 and serving as a reflective surface, and the LED chip 510 is disposed on the body 532 and is disposed on the side wall. surrounded by (534).

As described above, the light-emitting particle 100 according to the present invention can implement light emission in various wavelength bands by changing the composition ratio of components constituting the quantum dot core capable of a stable crystal structure or by adjusting the thickness of the shell. In addition, the quantum efficiency can be doubled by forming a shell surrounding the quantum dot core, the photodegradation phenomenon caused by the influence of oxygen or moisture can be prevented, and the FRET phenomenon can be prevented by increasing the thickness of the shell. Accordingly, the luminance of the LED package 500 including the light-emitting particles 100 can be increased, and the luminance of the liquid crystal display device including the LED package 500 is greatly improved.

[Quantum dot light emitting diode and display device]

Since the light emitting particles synthesized according to the present invention have excellent light emitting efficiency and can emit light in various wavelength ranges, they can be used as a light emitting material layer of a quantum-dot light emitting diode (QD-LED or QLED). there is. 7 is a cross-sectional view schematically illustrating a quantum dot light emitting diode having a normal structure in which light emitting particles are applied to a light emitting material layer according to an exemplary embodiment of the present invention.

As shown in FIG. 7, a quantum dot light emitting diode 600 according to an exemplary embodiment of the present invention includes a first electrode 610, a second electrode 620 facing the first electrode, and a first electrode ( 610) and the second electrode 620, and includes a light emitting layer 630 including an emitting material layer (EML, 650). For example, the light emitting layer 630 is formed between the first charge transfer layer 640 positioned between the first electrode 610 and the light emitting material layer 650 and between the light emitting material layer 650 and the second electrode 620. A second charge transfer layer 660 may be further included.

In this embodiment, the first electrode 610 may be an anode such as a hole injection electrode. The first electrode 610 may be formed on a substrate (not shown in FIG. 7) which may be glass or polymer. For example, the first electrode 610 may be indium-tin-oxide (ITO), indium-zinc-oxide (IZO), or indium-tin-zinc-oxide (indium-tin-oxide). tin-zinc oxide (ITZO), indium-copper-oxide (ICO), tin oxide (SnO ₂ ), indium oxide (In ₂ O ₃ ), cadmium:zinc oxide (Cd:ZnO), fluorine Doped or undoped, including: tin oxide (F:SnO ₂ ), indium:tin oxide (In:SnO ₂ ), gallium:tin oxide (Ga:SnO ₂ ) and aluminum:zinc oxide (Al:ZnO; AZO). It may be a non-metal oxide. Optionally, the first electrode 610 is made of a metal material including nickel (Ni), platinum (Pt), gold (Au), silver (Ag), iridium (Ir), or carbon nanotubes in addition to the aforementioned metal oxide. can

In this embodiment, the second electrode 620 may be a cathode such as an electron injection electrode. For example, the second electrode 620 may include a, Ba, Ca/Al, LiF/Ca, LiF/Al, BaF ₂ /Al, CsF/Al, CaCO ₃ /Al, BaF ₂ /Ca/Al, Al, Mg, It may be Au:Mg or Ag:Mg. For example, the first electrode 610 and the second electrode 620 may be stacked to a thickness of 50 to 300 nm.

In one exemplary embodiment, in the case of a bottom emission type light emitting diode, the first electrode 610 may be made of a transparent conductive metal such as ITO, IZO, ITZO, or AZO, and the second electrode 620 may be Ca. , Ba, Ca/Al, LiF/Ca, LiF/Al, BaF ₂ /Al, Al, Mg, Ag:Mg alloy, etc. may be used.

The first charge transfer layer 640 is positioned between the first electrode 610 and the light emitting material layer 650 . In this embodiment, the first charge transfer layer 640 may be a hole transfer layer supplying holes to the light emitting material layer 650 . For example, the first charge transfer layer 640 is a hole injection layer (HIL, 642) positioned adjacent to the first electrode 610 between the first electrode 610 and the light emitting material layer 650. and a hole transport layer (HTL, 644) positioned adjacent to the light emitting material layer 650 between the first electrode 610 and the light emitting material layer 650.

The hole injection layer 642 facilitates hole injection from the first electrode 610 into the light emitting material layer 650 . For example, the hole injection layer 642 may include poly(ethylene dioxythiophene):polystyrene sulfonate (PEDOT:PSS), tetrafluoro-tetracyano-quinodimethane (tetrafluoro- 4,4',4"-tris(diphenylamino)triphenylamine (4,4',4"-tris(diphenylamino)triphenylamine; TDATA) doped with tetracyano-quinodimethane; F4-TCNQ); For example, p-doped phthalocyanine such as F4-TCNQ doped zinc phthalocyanine (ZnPc), F4-TCNQ doped N,N'-diphenyl-N,N'-bis(1-naphthyl )-1,1'-biphenyl-4,4"-diamine (N,N'-diphenyl-N,N'-bis(1-naphtyl)-1,1'-biphenyl-4,4'-diamine α-NPD), hexaazatriphenylene-hexanitrile (HAT-CN), and combinations thereof, but the present invention is not limited thereto. A dopant such as F4-TCNQ may be doped in an amount of 1 to 20% by weight relative to the host.

The hole transport layer 644 transfers holes from the first electrode 610 to the light emitting material layer 650 . The hole transport layer 644 may be made of an inorganic or organic material. For example, when the hole transport layer 644 is made of an organic material, the hole transport layer 644 is 4,4'-N, N'-dicarbazolyl-biphenyl (4,4'-N, N'-dicarbazolyl-biphenyl ; CBP), N,N'-diphenyl-N,N'-bis(1-naphthyl)-1,1'-biphenyl-4,4"-diamine (N,N'-diphenyl-N,N '-bis(1-naphtyl)-1,1'-biphenyl-4,4''-diamine; α-NPD), N,N'diphenyl-N,N'-bis(3-methylphenyl)-(1 ,1'-biphenyl)-4,4'-diamine (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 (N, N'-bis (3-methylphenyl) -N, N'-bis (phenyl) - spiro; spiro-TPD), N,N'-di(4-(N,N'-diphenyl-amino)phenyl-N,N'-diphenylbenzidine (N,N'-di(4-(N, N'-diphenyl-amino)phenyl)-N,N'-diphenylbenzidine; DNTPD), 4,4',4 "-tris (N-carbazolyl-triphenylamine (4,4',4''-tris( Arylamines such as N-carbazolyl)-triphenylamine; TCTA), polyaniline, polypyrrole, poly(phenylene vinylene), copper phthalocyanine, aromatic tertiary amines (aromatic tertiary amine) or polynuclear aromatic tertiary amine, 4,4'-bis(p-carbazolyl)-1,1'-biphenyl compound (4,4'-bis(p-carbazolyl )-1,1'-biphenyl compound), N,N,N',N'-tetraarylbenzidine (N,N,N',N'-tetraarylbenzidine), PEDOT:PSS and its derivatives, poly-N-vinyl Carbazole derivatives (poly-N-vinylcarbazole derivatives), poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene](poly[2-methoxy-5-(2 -ethylhexyloxy)-1,4-phenylenevinylene]; MEH-PPV) or poly[2-methoxy-5-(3',7'-dimethyloctyloxy)1,4-phenylenevinylene](poly[2-methoxy-5-(3',7'' -dimethyloctyloxy)-1,4-phenylenevinylene]; poly(para)phenylenevinylene derivatives such as MOMO-PPV), polymethacrylate derivatives, poly(9,9-octylfluorene) ) (poly(9,9-octylfluorene)) and its derivatives, poly(spiro-fluorene) and its derivatives, N,N'-di(naphthalene-l-yl)-N , N'-diphenyl-benzidine (N, N'-di (naphthalene-l-yl) -N, N'-diphenyl-benzidine; NPB), tris (3-methylphenylphenylamino) -triphenylamine (tris( 3-methylphenylphenylamino)-triphenylamine; m-MTDATA), poly(9,9'-dioctylfluorene-co-N-(4-butylphenyl)diphenylamine (poly(9,9'-dioctylfluorene-co-N -(4-butylphenyl)diphenylamine; TFB), spiro-NPB (spiro-NPB), poly (9-vinylcarbazole) (poly (9-vinylcarbazole); PVK), and selected from the group consisting of combinations thereof It can be made of organic matter.

When the hole transport layer 644 is made of an inorganic material, the hole transport layer 644 is a metal oxide such as NiO, MoO ₃ , Cr ₂ O ₃ , Bi ₂ O ₃ or p-type ZnO, copper thiocyanate (CuSCN), Mo ₂ S, non-oxidizing equivalents such as p-type GaN, or combinations thereof.

In the drawing, the hole injection layer 642 and the hole transport layer 644 are divided as the first charge transfer layer 640, but the first charge transfer layer 640 may be formed of a single layer. For example, the hole injection layer 642 may be omitted and the first charge transfer layer 640 may be formed of only the hole transport layer 644, and the hole injection material (for example, PEDOT:PSS) may be doped with the hole transport organic material. may be done.

The first charge transfer layer 640 including the hole injection layer 642 and the hole transport layer 644 may be formed by a vacuum deposition process including vacuum vapor deposition or sputtering, spin coating, or drop coating. ), dip coating, spray coating, roll coating, flow coating, as well as solution processes such as casting, screen printing, or inkjet printing, alone or in combination. and can be used. For example, the thickness of the hole injection layer 642 and the hole transport layer 644 may be 10 nm to 200 nm, preferably 10 nm to 100 nm, but the present invention is not limited thereto.

The light emitting material layer 650 may be a layer filled with the light emitting particles 100 according to the present invention. The light-emitting particle 100 is composed of a quantum dot core 110 in which a perovskite component and a metal halide component are mixed, and a shell 120 surrounding the quantum dot core 110 and made of, for example, an amorphous silicon-based material.

For example, the light emitting material layer 650 may be formed by coating the first charge transfer layer 640 through a solution process of coating a dispersion containing the light emitting particles 100 in a solvent and volatilizing the solvent. . Methods of forming the light emitting material layer 650 include spin coating, drop coating, dip coating, spray coating, roll coating, and flow coating. coating) as well as a solution process such as a casting process, screen printing or inkjet printing method, alone or in combination.

In one exemplary embodiment, the light emitting material layer 650 may include the light emitting particles 100 having PL light emission characteristics of 440 nm, 530 nm, and 620 nm to manufacture a white light emitting diode. Optionally, the light-emitting material layer 650 includes the light-emitting particles 100 having any one color among red, green, and blue, and may be implemented to individually emit light with any one of them.

The second charge transfer layer 660 is positioned between the light emitting material layer 650 and the second electrode 620 . In this embodiment, the second charge transfer layer 660 may be an electron transfer layer supplying electrons to the light emitting material layer 650 . In one exemplary embodiment, the second charge transfer layer 660 is an electron injection layer positioned adjacent to the second electrode 620 between the second electrode 620 and the light emitting material layer 650. ;

The electron injection layer 662 facilitates electron injection from the second electrode 620 into the light emitting material layer 650 . For example, the electron injection layer 662 is made of a material in which fluorine is doped or bonded to a metal such as Al, Cd, Cs, Cu, Ga, Ge, In, Li, Al, Mg, In, Li, Ga, Titanium dioxide (TiO ₂ ) doped or undoped with Cd, Cs, Cu, etc., zinc oxide (ZnO), zirconium oxide (ZrO), tin oxide (SnO ₂ ), tungsten oxide (WO ₃ ), tantalum oxide (Ta ₂ O ₃ ) may be made of a metal oxide such as.

The electron transport layer 664 transfers electrons to the light emitting material layer 650 . The electron transport layer 664 may be made of an inorganic material and/or an organic material. When the electron transport layer 664 is made of an inorganic material, the electron transport layer 664 is titanium dioxide (TiO ₂ ) doped or undoped with Al, Mg, In, Li, Ga, Cd, Cs, Cu, or the like, or zinc oxide (ZnO). ), zirconium oxide (ZrO), tin oxide (SnO ₂ ), tungsten oxide (WO ₃ ), tantalum oxide (Ta ₂ O ₃ ), hafnium oxide (HfO ₃ ), aluminum oxide (Al ₂ O ₃ ), zirconium silicon oxide (ZrSiO ₄ ), barium titanium oxide (BaTiO ₃ ), barium zirconium oxide (BaZrO ₃ ) doped or not doped with metal/non-metal oxides such as and/or Al, Mg, In, Li, Ga, Cd, Cs, Cu, etc. It may be made of an inorganic material selected from the group consisting of semiconductor particles such as CdS, ZnSe, and ZnS, nitrides such as Si ₃ N ₄ , and combinations thereof.

When the electron transport layer 664 is made of an organic material, the electron transport layer 664 may include an oxazole-based compound, an isoxazole-based compound, a triazole-based compound, an isothiazole-based compound, an oxidiazole-based compound, a thiadizaol-based compound, or perylene. An organic substance such as a base compound or an aluminum complex can be used. Specifically, an organic material capable of constituting the electron transport layer 664 is 3-(biphenyl-4-yl)-5-(4-tetrabutylphenyl)-4-phenyl-4H-1,2,4-tria. Sol (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-benzyntriyl)-tris(1-phenyl-1-H-benzimiazole) (2,2',2"-(1,3,5-Benzinetriyl)-tris(1-phenyl-1-H-benzimidazole); TPBi), Tris(8-hydroxyquinoline) aluminum (Tris(8-hydroxyquinoline) )aluminum; Alq ₃ ), bis(2-methyl-8-quinolinato)-4-phenylphenolate aluminum (III) (bis(2-methyl-8-quninolinato)-4-phenylphenolate aluminum (Ⅲ); ), bis(2-methyl-quinolinato)(triphenylsiloxy) aluminum (III) (bis(2-methyl-quinolinato)(tripnehylsiloxy) aluminum (III); Salq) and combinations thereof may be selected, but the present invention is not limited thereto.

Similar to the first charge transfer layer 630, the second charge transfer layer 660 is shown as two layers of an electron injection layer 662 and an electron transport layer 664 in the figure, but the second charge transfer layer 660 The silver electron transport layer 664 may be formed of only one layer. For example, the second charge transfer layer 660 may be formed with one layer of the electron transport layer 664 obtained by blending cesium carbonate with the aforementioned inorganic electron transport material.

The second charge transfer layer 660 including the electron injection layer 662 and the electron transport layer 664 may be formed by spin coating, drop coating, dip coating, or spray coating. ), roll coating, and flow coating, as well as solution processes such as a casting process, screen printing, or inkjet printing, may be used alone or in combination. For example, the electron injection layer 662 and the electron transport layer 664 may be stacked to a thickness of 10 to 200 nm, preferably 10 to 100 nm.

As described above, the light-emitting particle 100 according to the present invention can implement light emission in various wavelength bands by changing the composition ratio of components constituting the quantum dot core capable of a stable crystal structure or by adjusting the thickness of the shell. In addition, the quantum efficiency can be doubled by forming a shell surrounding the quantum dot core, the photodegradation phenomenon caused by the influence of oxygen or moisture can be prevented, and the FRET phenomenon can be prevented by increasing the thickness of the shell. Accordingly, the light emitting efficiency and luminance of the quantum dot light emitting diode 700 to which the light emitting particles 100 according to the present invention are applied can be improved.

In FIG. 7, a hole transfer layer is positioned between a first electrode having a relatively low work function and the light emitting material layer, and an electron transfer layer is positioned between a second electrode having a relatively high work function and the light emitting material layer. A quantum dot light emitting diode having a structure has been described. A quantum dot light emitting diode may have an inverted structure rather than a normal structure, which will be described.

8 is a cross-sectional view schematically illustrating a quantum dot light emitting diode having an inverted structure in which an interface control layer is positioned between a light emitting material layer and a first charge transfer layer according to another exemplary embodiment of the present invention. As shown in FIG. 8, a quantum dot light emitting diode 700 according to an exemplary embodiment of the present invention includes a first electrode 710, a second electrode 720 facing the first electrode 710, and a first electrode The light emitting layer 730 including the light emitting material layer 750 positioned between the 710 and the second electrode 720 is included. The light emitting layer 730 includes a first charge transfer layer 740 positioned between the first electrode 710 and the light emitting material layer 750, and positioned between the second electrode 720 and the light emitting material layer 750. A second charge transfer layer 760 may be further included.

The first electrode 710 may be a cathode such as an electron injection electrode. For example, the first electrode 710 is ITO, IZO, ITZO, ICO, SnO ₂ , In ₂ O ₃ , Cd:ZnO, F:SnO ₂ , In:SnO _{2 , Ga:SnO 2 ,} and doped with AZO. It may be an undoped metal oxide or a metal material including nickel (Ni), platinum (Pt), gold (Au), silver (Ag), iridium (Ir), or carbon nanotubes in addition to the above-mentioned metal oxide.

The second electrode 720 may be an anode such as a hole injection electrode. For example, the second electrode 720 is 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 Au:Mg or Ag:Mg. For example, the first electrode 710 and the second electrode 720 may be stacked to a thickness of 50 to 300 nm.

The first charge transfer layer 740 may be an electron transfer layer supplying electrons to the light emitting material layer 750 . In one exemplary embodiment, the first charge transfer layer 740 includes an electron injection layer 742 positioned adjacent to the first electrode 710 between the first electrode 710 and the light emitting material layer 750 and , An electron transport layer 744 positioned adjacent to the light emitting material layer 750 between the first electrode 710 and the light emitting material layer 750 .

The electron injection layer 742 is made of a material in which fluorine is doped or bonded to a metal such as Al, Cd, Cs, Cu, Ga, Ge, In, or Li, or Al, Mg, In, Li, Ga, Cd, or Cs. Titanium dioxide (TiO ₂ ), zinc oxide (ZnO), zirconium oxide (ZrO), tin oxide (SnO ₂ ), tungsten oxide (WO ₃ ), tantalum oxide (Ta ₂ O ₃ ), doped or undoped with Cu, etc. It may be made of a metal oxide such as.

The electron transport layer 744 may be made of an inorganic material and/or an organic material. When the electron transport layer 744 is made of an inorganic material, the electron transport layer 744 is TiO ₂ , ZnO, ZrO, SnO ₂ , WO that is doped or undoped with Al, Mg, In, Li, Ga, Cd, Cs, Cu, or the like. ₃ , Ta ₂ O ₃ , HfO ₃ , Al ₂ O ₃ , ZrSiO ₄ , BaTiO ₃ , BaZrO ₃ and/or doped with metal/non-metal oxides such as Al, Mg, In, Li, Ga, Cd, Cs, Cu, etc. It may be made of an inorganic material selected from the group consisting of semiconductor particles such as undoped or undoped CdS, ZnSe, and ZnS, nitrides such as Si ₃ N ₄ , and combinations thereof.

When the electron transport layer 744 is made of an organic material, the electron transport layer 744 may include an oxazole-based compound, an isoxazole-based compound, a triazole-based compound, an isothiazole-based compound, an oxidiazole-based compound, a thiadizaol-based compound, or perylene. A base compound or an aluminum complex can be used. Specifically, organic materials that may constitute the electron transport layer 744 include TAZ, BCP, TPBi, It may be made of an organic material selected from the group consisting of Alq ₃ , Balq, Salq, and combinations thereof, but the present invention is not limited thereto.

The first charge transfer layer 740 may be formed of only one layer of the electron transport layer 744 . For example, the first charge transfer layer 744 may be formed with one layer of the electron transport layer 744 obtained by blending cesium carbonate with the aforementioned inorganic electron transport material. For example, the electron injection layer 742 and the electron transport layer 744 may be stacked to a thickness of 10 to 200 nm, preferably 10 to 100 nm.

The light-emitting material layer 750 includes light-emitting particles 100 composed of a quantum dot core 110 and a shell 120 according to the present invention.

In this embodiment, the second charge transfer layer 760 may be a hole transfer layer supplying holes to the light emitting material layer 750 . In one exemplary embodiment, the second charge transfer layer 760 includes a hole injection layer 762 positioned adjacent to the second electrode 720 between the second electrode 720 and the light emitting material layer 750 and , and a hole transport layer 764 positioned adjacent to the light emitting material layer 750 between the second electrode 720 and the light emitting material layer 750 .

The hole injection layer 762 is PEDOT:PSS, TDATA doped with F4-TCNQ, eg p-doped phthalocyanine such as ZnPc doped with F4-TCNQ, α-NPD doped with F4-TCNQ), HAT It may be made of a material selected from the group consisting of -CN and combinations thereof, but the present invention is not limited thereto. For example, a dopant such as F4-TCNQ may be doped in an amount of 1 to 20% by weight with respect to the host.

The hole transport layer 764 may be made of an inorganic or organic material. For example, when the hole transport layer 464 is made of an organic material, the hole transport layer 464 may include aryl amines such as CBP, α-NPD, TPD, spiro-TPD, DNTPD, and TCTA, polyaniline, polypyrrole, poly(phenylene vinylene), copper phthalocyanine, aromatic tertiary amine or polynuclear aromatic tertiary amine, 4,4'-bis (p-carbazolyl)-1,1'-biphenyl compound (4,4'-bis(p-carbazolyl)-1,1'-biphenyl compound), N,N,N',N'-tetraarylbenzidine (N,N,N',N'-tetraarylbenzidine), PEDOT:PSS and its derivatives, poly-N-vinylcarbazole derivatives, and poly(para-methylamines) such as MEH-PPV or MOMO-PPV. ) phenylenevinylene derivatives, polymethacrylate derivatives, poly(9,9-octylfluorene) and its derivatives, poly(spiro- It may be made of an organic material selected from the group consisting of fluorene) (poly(spiro-fluorene)) and its derivatives, NPB, m-MTDATA, TFB, (spiro-NPB, PVK, and combinations thereof.

When the hole transport layer 764 is made of an inorganic material, the hole transport layer 764 is a metal oxide such as NiO, MoO ₃ , Cr ₂ O ₃ , Bi ₂ O ₃ or p-type ZnO, copper thiocyanate (CuSCN), Mo ₂ S, non-oxidizing equivalents such as p-type GaN, or combinations thereof.

The second charge transfer layer 760 may be formed of a single layer. For example, the hole injection layer 762 may be omitted and the second charge transfer layer 760 may consist of only the hole transport layer 764, and the hole injection material (for example, PEDOT:PSS) may be doped with the hole transport organic material. may be done. The hole injection layer 762 and the hole transport layer 764 may have a thickness of 10 nm to 200 nm, preferably 10 nm to 100 nm, but the present invention is not limited thereto.

According to the present invention, it is possible to implement light emission in various wavelength bands, and it is possible to improve the light-emitting efficiency and luminance of the quantum dot light-emitting diode 700 to which the light-emitting particles 100 having excellent light-emitting efficiency are applied.

Subsequently, a quantum dot light emitting display device having a quantum dot light emitting diode in which light emitting particles according to the present invention are applied to a light emitting layer will be described. 9 is a schematic cross-sectional view of a quantum dot light emitting display device according to an exemplary embodiment of the present invention.

As shown in FIG. 9, the quantum dot light emitting display device 800 includes a substrate 810, a thin film transistor (Tr) as a driving element positioned on the substrate 810, and light emitting connected to the thin film transistor (Tr). Diode (D) is included.

A semiconductor layer 822 made of an oxide semiconductor material or polycrystalline silicon is formed on the substrate 810 . When the semiconductor layer 822 is made of an oxide semiconductor material, a light-shielding pattern (not shown) may be formed under the semiconductor layer 822, and the light-shielding pattern prevents light from entering the semiconductor layer 822 to prevent light from entering the semiconductor layer 822. Layer 822 is prevented from being degraded by light. Alternatively, the semiconductor layer 822 may be made of polycrystalline silicon, and in this case, both edges of the semiconductor layer 822 may be doped with impurities.

A gate insulating layer 824 made of an insulating material is formed on the semiconductor layer 822 . The gate insulating layer 824 may be formed of an inorganic insulating material such as silicon oxide (SiO ₂ ) or silicon nitride (SiNx). A gate electrode 830 made of a conductive material such as metal is formed on the gate insulating layer 824 to correspond to the center of the semiconductor layer 822 .

An interlayer insulating layer 832 made of an insulating material is formed on the gate electrode 830 . The interlayer insulating film 832 may be formed of an inorganic insulating material such as silicon oxide (SiO ₂ ) or silicon nitride (SiNx), or an organic insulating material such as benzocyclobutene or photo-acryl. there is.

The interlayer insulating film 832 has first and second contact holes 834 and 836 exposing both sides of the semiconductor layer 822 . The first and second contact holes 834 and 836 are spaced apart from the gate electrode 830 on both sides of the gate electrode 830 . A source electrode 840 and a drain electrode 842 made of a conductive material such as metal are formed on the interlayer insulating film 832 .

The source electrode 840 and the drain electrode 842 are spaced apart from each other around the gate electrode 830, and both sides of the semiconductor layer 822 through the first and second contact holes 834 and 836, respectively. make contact

The semiconductor layer 822, the gate electrode 830, the source electrode 840, and the drain electrode 842 form a thin film transistor Tr as a driving element.

In FIG. 9 , the thin film transistor Tr has a coplanar structure in which a gate electrode 830, a source electrode 840, and a drain electrode 842 are positioned on top of a semiconductor layer 822. Unlike this, The thin film transistor Tr may have an inverted staggered structure in which a gate electrode is positioned below the 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, a gate line and a data line cross each other to define a pixel area, and a switching element connected to the gate line and the data line is further formed. The switching element is connected to the thin film transistor Tr, which is a driving element. In addition, the power line is formed parallel to and spaced apart from the gate line or the data line, and a storage capacitor is further configured to maintain the voltage of the gate electrode of the thin film transistor (Tr), which is a driving element, constant during one frame. can

Meanwhile, a protective layer 850 having a drain contact hole 852 exposing the drain electrode 842 of the thin film transistor Tr is formed to cover the thin film transistor Tr.

On the protective layer 850, a first electrode 910 connected to the drain electrode 842 of the thin film transistor Tr through the drain contact hole 852 is formed separately for each pixel area. The first electrode 910 may be an anode or a cathode, and may be made of a conductive material having a relatively high work function value. For example, the first electrode 910 is doped with ITO, IZO, ITZO, ICO, SnO ₂ , In ₂ O ₃ , Cd:ZnO, F:SnO ₂ , In:SnO ₂ , Ga:SnO ₂ and AZO. It may be an undoped or undoped metal oxide, or may be made of a metal material including nickel (Ni), platinum (Pt), gold (Au), silver (Ag), iridium (Ir), or carbon nanotubes in addition to the above-mentioned metal oxides. .

Meanwhile, when the quantum dot light emitting display device 800 of the present invention is a top-emission type, a reflective electrode or a reflective layer may be further formed below the first electrode 910 . For example, the reflective electrode or reflective layer may be made of an aluminum-palladium-copper (APC) alloy.

In addition, a bank layer 868 covering an edge of the first electrode 910 is formed on the passivation layer 850 . The bank layer 868 exposes the center of the first electrode 910 corresponding to the pixel area.

A light emitting layer 930 including the light emitting particles 100 according to the present invention is formed on the first electrode 910 . The light emitting layer 930 may be formed of only a light emitting material layer, but may include a plurality of charge transfer layers to increase light emitting efficiency. For example, a first charge transfer layer (640, 740, see FIGS. 7 and 8) is formed between the first electrode 910 and the light emitting layer 930, and between the light emitting layer 930 and the second electrode 920. 2 charge transfer layers 660 and 760 (see FIGS. 7 and 8) may be further formed.

A second electrode 920 is formed on the substrate 810 on which the light emitting layer 930 is formed. The second electrode 920 is positioned on the entire surface of the display area and may be made of a conductive material having a relatively low work function value, and may be a cathode or an anode. For example, the second electrode 920 may be Ca, Ba, Ca/Al, LiF/Ca, LiF/Al, BaF ₂ /Al, CsF/Al, CaCO ₃ /Al, BaF ₂ /Ca/Al, Al, Mg, Au:Mg or Ag:Mg.

As described above, the light-emitting particle 100 according to the present invention can implement light emission in various wavelength bands by changing the composition ratio of components constituting the quantum dot core capable of a stable crystal structure or by adjusting the thickness of the shell. In addition, the quantum efficiency can be doubled by forming a shell surrounding the quantum dot core, the photodegradation phenomenon caused by the influence of oxygen or moisture can be prevented, and the FRET phenomenon can be prevented by increasing the thickness of the shell. Accordingly, the luminance of the quantum dot light emitting display device 800 can be improved by increasing the light emitting efficiency of the quantum dot light emitting diode D to which the light emitting particles 100 according to the present invention are applied.

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

Example 1: CH ₃ NH ₃ SnBr ₃ -SnBr ₂ /SiO ₂ synthesis

A CH ₃ NH 3 Br precursor was synthesized by reacting 1 mole of methylamine (CH ₃ NH ₂ ) with 1 mole of hydrogen bromide (HBr, ₄₈ %, Aldrich Co.) as follows. In order to lower the temperature of 30 mL of methylamine (33% dissolved in methyl alcohol, Aldrich Co.) solution in a three-necked round flask, it was stirred in ice water conditions. Then, 36.7 mL (0.68 mol) of hydrogen bromide (HBr, 48%, Aldrich) was slowly added dropwise to 30 mL (0.68 mol) of methylamine solution. The reaction was terminated after 2 hours, and the reaction stock solution was filtered under reduced pressure at 50° C. to obtain a precipitate as a reaction product. The reaction product was purified three times with diethyl ether using a centrifuge, and the white reaction product, CH ₃ NH ₃ Br, was dried in a vacuum oven at room temperature for 24 hours. A light-emitting particle core (hereinafter referred to as CH ₃ NH ₃ SnBr ₃ core) in which CH ₃ NH ₃ SnBr ₃ and SnBr ₂ (99%, Aldrich) were mixed was synthesized as follows. 0.072 g (0.64 mmol) of CH ₃ NH ₃ Br and 0.178 g (0.64 mmol) SnBr ₂ were added to a three-necked round flask under a nitrogen stream in a vacuum glove box. The reaction flask contained 100 μl of n-octylamine (≥ 99.5%, Aldrich), 2 mL of oleic acid (acid (OA, 90%, Aldrich) and 20 mL of ), N-dimethylformamide (DMF, analytical grade) under a nitrogen atmosphere. , Aldrich) into a three-necked round reaction flask and stirred until a clear solution. 10 mL of the reaction solution was collected and slowly added dropwise at 0.1 mL/min to 100 mL of toluene (analytical grade, H ₂ O content 0.018%, Daejeong Chemical & Gold, Korea) in another one-neck Erlenmeyer flask. The reaction solution was stirred for 24 hours under a nitrogen stream to complete the reaction. The reaction solution was purified by centrifugation at 10,000 rpm for 10 minutes to obtain a precipitate mainly containing CH ₃ NH ₃ SnBr ₃ .

Subsequently, a silica shell was formed on the core in the following manner. In a 50 mL three-neck round flask, 20 mL of toluene (including 0.0623% H ₂ O) was added to a quantum dot core containing 1.2 mg CH ₃ NH ₃ SnBr ₃ as a main component, and 100 μl of TMOS (tetra methyl orthosilicate, manufactured by Aldrich) was added. ) was injected under a nitrogen stream and stirred. While maintaining the reaction temperature at 25° C. and humidity at 60%, the mixture was stirred for 36 hours and the reaction was terminated. The reaction solution was purified by centrifugation at 10,000 rpm for 10 minutes to obtain CH ₃ NH ₃ SnBr ₃ /SiO ₂ precipitate (hereafter referred to as CH ₃ NH ₃ SnBr ₃ /SiO ₂ or MASnBr ₃ /SiO ₂ ). FIG. 10 shows an energy band diagram of the synthesized CH ₃ NH ₃ SnBr ₃ /SiO ₂ , and FIG. 11 shows an emission form of CH ₃ NH ₃ SnBr ₃ /SiO ₂ . It was confirmed that the synthesized CH ₃ NH ₃ SnBr ₃ /SiO ₂ light-emitting particles emit green light.

Example 2: CH ₃ NH ₃ SnI ₃ -SnI ₂ /SiO ₂ synthesis

The precursor CH ₃ NH ₃ I was synthesized in the following manner. The reaction temperature of 30 mL of methylamine solution in a three-necked round flask was stirred in ice water conditions to make it 0 ° C. 51 mL (0.68 mol) hydrogen iodide (HI, 47%, Aldrich Co.) was slowly added dropwise to 30 mL (0.68 mol) of methylamine solution. After 2 hours, the reaction was terminated, and the reaction stock solution was filtered under reduced pressure at 50° C. to obtain a precipitate as a result of the reaction. The reaction product was purified three times with diethyl ether through a centrifuge, and the white reaction product, CH ₃ NH ₃ I, was dried in a vacuum oven at room temperature for 24 hours.

A light emitting particle core (hereinafter referred to as CH ₃ NH ₃ SnBr ₃ core) in which CH ₃ NH ₃ SnI ₃ and SnI ₂ (99%, Aldrich) were mixed was synthesized as follows. 0.119 g (0.64 mmol) of CH ₃ NH ₃ I and 0.238 g (0.64 mmol) SnI ₂ were added to a three-necked round flask under a nitrogen atmosphere in a vacuum glove box. In the reaction flask, 40 μl of n-octylamine, 2 mL of oleic acid, and 10 mL of THF (tetrahydrofuran, 99.5%, Aldrich) were injected into a three-necked round reaction flask under a nitrogen stream, and the mixture was stirred until a clear solution. 2 mL of the reaction solution was collected and slowly added dropwise at 0.1 mL/min to 50 mL of toluene in another one-neck Erlenmeyer flask. The reaction solution was stirred for 24 hours under a nitrogen stream to complete the reaction. The reaction solution was purified by centrifugation at 10,000 rpm for 10 minutes to obtain a precipitate mainly composed of CH ₃ NH ₃ SnI ₃ .

Subsequently, 1.2 mg of CH ₃ NH ₃ SnI _3- based quantum dot core and 20 mL of toluene (including 0.0623% H ₂ O) were placed in a 50 mL three-necked round flask, and 100 μl TMOS was injected under a nitrogen stream and stirred. . While maintaining the reaction temperature at 25° C. and the humidity at 60%, the mixture was stirred for 36 hours and the reaction was terminated. The reaction solution was purified by centrifugation at 10,000 rpm for 10 minutes to obtain CH ₃ NH ₃ SnI ₃ /SiO ₂ precipitate (hereafter referred to as CH ₃ NH ₃ SnI ₃ /SiO ₂ or MASnI ₃ /SiO ₂ ). FIG. 12 shows an energy band diagram for the synthesized CH ₃ NH ₃ SnI ₃ /SiO ₂ , and FIG. 13 shows an emission form of the synthesized CH ₃ NH ₃ SnI ₃ /SiO ₂ . It was confirmed that the synthesized CH ₃ NH ₃ SnI ₃ /SiO ₂ light-emitting particles emit red light.

Comparative Example 1: CH ₃ NH ₃ SnBr ₃ -SnBr ₂

In Example 1, a quantum dot core without forming SiO ₂ as a shell was synthesized (hereinafter referred to as CH ₃ NH ₃ SnBr ₃ or MASnBr ₃ ).

Comparative Example 2: CH ₃ NH ₃ SnIr ₃ -SnI ₂

In Example 1, a quantum dot core without SiO ₂ as a shell was synthesized (hereinafter referred to as CH ₃ NH ₃ SnI ₃ /SiO ₂ or MASnI ₃ /SiO ₂ ).

Comparative Example 3: CH ₃ NH ₃ SnBr ₃ -SnBr ₂ /TiO ₂ synthesis

The procedure of Example 1 was repeated except that TiO ₂ was used instead of SiO ₂ used as the shell in Example 1 (hereafter referred to as CH ₃ NH ₃ SnIBr ₃ /TiO ₂ or MASnBr ₃ /TiO ₂ ).

Experimental Example 1: Confirmation of core and shell

The light-emitting particles synthesized in Example 1 were analyzed using TEM, and XRD analysis was performed on the light-emitting particles synthesized in Examples 1 and 2 and Comparative Examples 1 and 2, respectively. TEM analysis results are shown in FIG. 14 and XRD analysis results are shown in FIG. 15 . As shown in FIG. 14, light-emitting particles having a form in which a silica shell is surrounded by a quantum dot core (a portion indicated in bold on the lower right) were confirmed. In addition, as shown in FIG. 15 (the part indicated by (001) in FIG. 15), compared to the light emitting particle composed of only the quantum dot core, the peak intensity of the light emitting particle including the shell is increased (MASnBr ₃ of Example 1). /SiO ₂ compared with MASnBr ₃ in Comparative Example 1), and the width of the peak narrowed (Comparison between MASnBr ₃ /SiO ₂ in Example 1 and MASnBr ₃ in Comparative Example 1, MASnI ₃ /SiO ₂ in Example 2 and Comparative Example) Compare MASnI ₃ of 2). This result means that a more stable crystal structure was obtained when the silica shell was included, compared to the light emitting particle composed only of the quantum dot core.

Experimental Example 2: Evaluation of luminescence characteristics

Luminescent particles surrounded by silica shells synthesized in Examples 1 and 2, light emitting particles consisting only of quantum dot cores in Comparative Examples 1 and 2, and titanium dioxide shells in Comparative Example 3 properties were evaluated. The absorbance measurement results are shown in FIG. 16A, and the emission characteristics are shown in FIGS. 16B and 16C. Meanwhile, Table 1 shows emission characteristics of the light-emitting particles synthesized in Examples and Comparative Examples, including emission peak, full width at half maximum (FWHM), and quantum yield (QY).

Evaluation of luminescence properties Example luminescent particles luminescence peak FWHM
(nm) QY(%) Example 1 MASnBr ₃ /SiO ₂ 522 25 60 Example 2 MASnI ₃ /SiO ₂ 615 27 44 Comparative Example 1 MASnBr ₃ 525 19 20 Comparative Example 2 MASnI ₃ 615 35 22 Comparative Example 3 MASnBr ₃ /TiO ₂ 529 25 27

As shown in these measurement results, the emission peak intensity of the light-emitting particles having a shell of silicon-based amorphous material according to the present invention is increased compared to the light-emitting particles having a titanium dioxide shell or particles composed of only a quantum dot core without a shell. and the quantum efficiency was greatly improved. Specifically, the quantum efficiency was improved by up to 200% compared to the quantum dot core in which the shell was not formed, and the quantum efficiency was increased by 122% compared to the light emitting particle in which the titanium dioxide core was formed. From these results, it can be seen that by forming the silicon-based shell, the luminous efficiency of the quantum dot core can be increased and deterioration of the quantum dot core can be prevented. Therefore, it was confirmed that the light emitting particles having a silicon-based shell formed on the quantum dot core having an alloy structure according to the present invention can be used as a light emitting material for a light emitting film or an LED package as well as a light emitting material for a quantum dot light emitting diode.

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 idea described in the above embodiments and examples. Rather, those skilled in the art to which the present invention pertains can easily make various modifications and changes based on the above-described embodiments and examples. However, it will be clear from the appended claims that all of these variations and modifications fall within the scope of the present invention.

100, 100A, 100B: luminescent particles
110, 110a, 110b: core 120: shell
200, 300: light emitting film 400, 800: display device
500: LED package
600, 700, D: quantum dot light emitting diode

Claims (15)

A quantum dot core having a perovskite component and a mixed alloy structure of a metal halide component; and
A shell surrounding the quantum dot core and made of a silicon-based material
including,
The quantum dot core is a light-emitting particle represented by Formula 1 below.
Formula 1
[ABX ₃ ] _a [BX ₂ ] _1-a
(In Formula 1, [ABX ₃ ] represents a perovskite component, and [BX ₂ ] represents a metal halide component; A is an organic ammonium or alkali metal, and B is tin (Sn) or germanium (Ge) 4A is selected from the group consisting of group metals, divalent transition metals, alkaline earth metals, and combinations thereof, X is selected from the group consisting of Cl, Br, I, and combinations thereof; a is the mole fraction of the [ABX ₃ ] component , where 0 < a < 1)
According to claim 1,
The quantum dot core is a light-emitting particle in which the perovskite component [ABX ₃ ] and the metal halide component [BX ₂ ] constituting the quantum dot core are mixed in a molar ratio of 1:1 to 5:1.
According to claim 1,
Wherein A is an unsubstituted or fluorine-substituted C1-C10 alkylammonium, and B is Sn or Ge.
According to claim 1,
The shell is a light emitting particle of silica (SiO ₂ ) or silicon nitride (SiNx).
According to claim 1,
The shell is a light-emitting particle of an amorphous material.
A light-emitting film comprising the light-emitting particles according to any one of claims 1 to 5.
liquid crystal panel;
a backlight unit located below the liquid crystal panel and including a light source;
The light-emitting film according to claim 6 located between the liquid crystal panel and the backlight unit.
A liquid crystal display device comprising a.
LED chips; and
An encapsulation portion covering the LED chip and including the light-emitting particles according to any one of claims 1 to 5
LED package containing a.
A backlight unit including the LED package according to claim 8; and
Liquid crystal panel positioned above the backlight unit
A liquid crystal display device comprising a.
first electrode;
a second electrode facing the first electrode; and
A light-emitting layer disposed between the first electrode and the second electrode and comprising the light-emitting particles according to any one of claims 1 to 5
A quantum dot light emitting diode comprising a.
Board;
Located on the substrate, the quantum dot light emitting diode according to claim 10; and
A driving element positioned between the substrate and the light emitting diode and connected to the light emitting diode
Quantum dot light emitting display device comprising a. According to claim 1,
The quantum dot core is a light-emitting particle having a uniform alloy structure.
According to claim 1,
The quantum dot core is a light-emitting particle having a hardness alloy (gradient alloy) structure.
According to claim 1,
The shell is a light-emitting particle made of silicon nitride (SiNx).
According to claim 1,
The quantum dot core is a light-emitting particle having a single alloy structure.

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