KR102251945B1 - An organic emitting diode - Google Patents

Abstract

An organic light emitting diode according to an embodiment of the present invention includes: a lower electrode, an organic light emitting layer, and an upper electrode sequentially stacked on a substrate; A buffer layer including a dielectric material on the upper electrode; A nuclear layer formed of a material having a surface energy different from that of the buffer layer on the buffer layer; And a light scattering layer including a plurality of polygonal light scattering crystals anisotropically grown from the nuclear layer on the nuclear layer. In this case, each of the light scattering crystals may have a width of 150 nm to 1 μm and a height of 150 nm to 1 μm.

Description

An organic emitting diode

The present invention relates to an organic light emitting diode, and more particularly, to an organic light emitting diode having a surface structure capable of improving light extraction efficiency, and a method of manufacturing the same.

An organic light emitting diode (OLED) is a self-emission type device that emits light by electrically exciting an organic light emitting material. The organic light emitting diode includes a substrate, a lower electrode, an upper electrode, and an organic light emitting layer formed between the lower electrode and the upper electrode. Holes or electrons supplied from the lower electrode and the upper electrodes are combined in the organic emission layer to generate light emitted to the outside.

The external energy efficiency, which indicates the luminous efficiency of the organic light emitting diode, can be expressed as the product of the internal energy efficiency of the device and the light extraction efficiency. In the process of passing through the interface between layers with different refractive indices, the light emitted from the organic light-emitting layer cannot be emitted outside the organic light-emitting diode due to total reflection and surface plasmon absorption, but is absorbed inside each layer, so the light extraction efficiency is generally 20 It may not exceed %. The light that is trapped in each layer in the organic light emitting diode and is guided inside the layer is called waveguide mode light, and the light trapped in the glass substrate is called substrate mode light. Light emitted to the outside air through the interface of each layer is called emission mode light. Transforming the waveguide mode light and the substrate mode light into emission mode light and emitting it to the outside of the device is called light extraction.

In addition to the waveguide mode light and the substrate mode light, the amount of light lost due to a surface plasmon effect by a metal film used as an upper electrode is also significant. The loss of surface plasmon of the metal layer may vary greatly depending on the structure and thickness of the organic emission layer. Accordingly, research has been conducted to reduce light absorption due to the surface plasmon effect and increase light extraction efficiency so that light can be emitted to the outside without being guided within the organic light emitting diode.

An object to be solved by the present invention is to provide an organic light emitting diode having a surface structure capable of minimizing surface plasmon absorption and exhibiting high light extraction efficiency.

An organic light emitting diode according to an embodiment of the present invention includes: a lower electrode, an organic light emitting layer, and an upper electrode sequentially stacked on a substrate; A buffer layer including a dielectric material on the upper electrode; A nuclear layer formed of a material having a surface energy different from that of the buffer layer on the buffer layer; And a light scattering layer including a plurality of polygonal light scattering crystals anisotropically grown from the nuclear layer on the nuclear layer. In this case, each of the light scattering crystals may have a width of 150 nm to 1 μm and a height of 150 nm to 1 μm.

The organic light emitting diode according to embodiments of the present invention may include a buffer layer, a nuclear layer, and a light scattering layer sequentially formed on the upper electrode. When light is emitted to the outside through an upper electrode made of a metal electrode or a transparent electrode, the light scattering layer can minimize absorption of surface plasmon and improve light extraction efficiency. Furthermore, since the light-scattering layer can be formed to have dense polygonal pyramid-shaped light-scattering crystals even under room temperature conditions, an organic light-emitting diode having higher efficiency can be provided.

1 is a cross-sectional view of an organic light emitting diode according to an embodiment of the present invention.
2 is a cross-sectional view of an organic light emitting diode according to another embodiment of the present invention.
3 shows an SEM photograph of a light scattering layer (AgCl 500nm thin film) formed directly on a glass substrate by using a thermal evaporation method at room temperature.
4A shows an SEM photograph of a nuclear layer formed on a glass substrate by using a thermal evaporation method at room temperature.
4B shows an SEM photograph of a light scattering layer formed on the nuclear layer 60 by using a thermal evaporation method at room temperature.

In order to fully understand the configuration and effects of the present invention, preferred embodiments of the present invention will be described with reference to the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, and may be implemented in various forms and various changes may be added. However, it is provided to complete the disclosure of the present invention through the description of the present embodiments, and to completely inform the scope of the present invention to those of ordinary skill in the art to which the present invention pertains.

In the present specification, when a component is referred to as being on another component, it means that it may be formed directly on the other component or that a third component may be interposed therebetween. In addition, in the drawings, the thickness of the components is exaggerated for effective description of the technical content. Parts indicated by the same reference numerals throughout the specification represent the same elements.

Embodiments described herein will be described with reference to cross-sectional views and/or plan views, which are ideal exemplary views of the present invention. In the drawings, thicknesses of films and regions are exaggerated for effective description of technical content. Accordingly, regions illustrated in the drawings have schematic properties, and the shapes of regions illustrated in the drawings are intended to illustrate a specific shape of a device region and are not intended to limit the scope of the invention. In various embodiments of the present specification, terms such as first, second, and third are used to describe various elements, but these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. The embodiments described and illustrated herein also include complementary embodiments thereof.

The terms used in the present specification are for describing exemplary embodiments and are not intended to limit the present invention. In this specification, the singular form also includes the plural form unless specifically stated in the phrase. As used in the specification, "comprises" and/or "comprising" does not exclude the presence or addition of one or more other components.

Example One

1 is a cross-sectional view of an organic light emitting diode according to an embodiment of the present invention. Organic light-emitting diodes can be classified into an upper emission type, a lower emission type, and a transparent type (double-sided emission type). In the lower emission type structure, since light generated in the organic emission layer is reflected from the metal upper electrode and is emitted toward the transparent lower electrode, most of the generated light is emitted toward the lower electrode. In the top light emitting structure, the upper electrode may be formed of a very thin metal or a transparent electrode. In addition, by using a reflective metal electrode as the lower electrode or by disposing a reflective layer under the transparent lower electrode, most of the generated light can be emitted toward the upper electrode. In the transparent type, the upper and lower electrodes are formed as transparent electrodes through which light is transmitted, so that light can be emitted in both directions. In embodiments of the present invention, a top emission type and/or a transparent type organic light emitting diode will be described.

Referring to FIG. 1, a lower electrode 20 may be formed on a substrate 10. The substrate 10 may include a glass substrate, a quartz substrate, a plastic substrate, or a metal substrate. For example, the substrate 10 may be used as a reflective substrate. The lower electrode 20 may include a transparent conductive material. The lower electrode 20 may be, for example, one of transparent conductive oxides (TCO) or conductive carbon materials. More specifically, the lower electrode 20 may include indum tin oxide (ITO) or indium zinc oxide (IZO). According to another embodiment, the lower electrode 20 may include a conductive organic thin film. The lower electrode 20 may include at least one of conductive organic materials such as copper iodide, polyaniline, poly(3-methylthiophene), and polypyrrole. According to another embodiment, the lower electrode 20 may include a graphene thin film.

An organic emission layer 30 may be formed on the lower electrode 20. The organic emission layer 30 includes a hole injection layer 32a, a hole transport layer 32b, an emission layer 34, an electron transport layer 36a, and an electron injection layer 36b sequentially stacked on the lower electrode 20. Can include.

The hole injection layer 32a is copper ferrocyanine (Copper Phthalocyanine: CuPc), TNANA (4,4', 4"-tris[N-(1-naphthyl)-N-phenylamino]-triphenyl-amine) ), TCTA (4,4'4"-tris (N-carbazolyl), PEDOT (poly (3,4-ethylenedioxythiophene)), PANI (polyaniline; polyaniline), and PSS (polystyrenesulfonate) selected from It may include at least one.

The Highest Occupied Molecular Orbital (HOMO) is the highest energy level of the valence band, and The Lowest Unoccupied Molecular Orbital (LUMO) represents the lowest energy level of the conduction band.

By reducing the difference between the work function level of the lower electrode 20 and the HOMO level of the hole transport layer 32b, the hole injection layer 32a is transferred from the lower electrode 20 to the hole transport layer 32b. It can perform a function of facilitating the injection of holes. Accordingly, the driving current or driving voltage of the organic light emitting diode can be reduced by the hole injection layer 32a.

The hole transport layer 32b is a polymer derivative containing poly(9-vinylcarbazole), a polymer derivative containing 4,4'-dicarbazolyl-1,1'-diamine), or NPB(4,4'-dis[ A high molecular derivative containing N-(1-naphthyl-1-)-N-Phenyl-amino]-biphenyl), a low molecular derivative containing triarylamine, a low molecular derivative containing pyrazoline, or a hole It may contain organic molecules containing a holetransporting moiety. The hole transport layer 32b may provide holes moved through the hole injection layer 32a to the emission layer 34. The HOMO level of the hole transport layer 32b may be higher than the HOMO level of the emission layer 34.

The light-emitting layer 34 may include a fluorescent material or a phosphorescent light-emitting material. The emission layer 34 includes, for example, DPVBi, IDE 120, IDE 105, Alq3, CBP, DCJTB, BSN, DPP, DSB, PESB, PPV derivative, PFO derivative, C545t, Ir(ppy)3, PtOEP. can do. The emission layer 34 may be a single layer or multiple layers. The emission layer 34 may generate light of a first color, a second color, a third color, or white light. According to an embodiment, the first to third colors may be any one of red, green, and blue, respectively. In contrast, the first to third colors may be any one of cyan, magenta, and yellow, respectively.

The electron transport layer 36a is TPBI(2,2',2'-(1,3,5-phenylene)-tris[1-phenyl-1H-benzimidazole]), Poly(penylquinoxaline), 1,3,5- tris[(6,7-dimethyl-3-phenyl)quinoxaline-2-yl]benzene(Me-TPQ), Polyquinoline, tris(8-hydroxyquinoline)aluminum(Alq3), (6-N,N-diethylamino-1- It may include at least one of organic molecules containing methyl-3-phenyl-1H-pyrazolo[3,4-b]quinoline}(PAQ-Net2) or an electron transporting moiety.

The electron injection layer 36b may include a material having high electron mobility. The electron injection layer 36b may include lithium (Li), magnesium (Mg), aluminum (Al), calcium (Ca), silver (Ag), or cesium (Cs). The electron injection layer 36b may include, for example, lithium fluoride (LiF) or cesium fluoride (CsF). The electron injection layer 36b may perform a function of stably supplying electrons to the emission layer 34.

For example, the electron transport layer 36a and/or the electron injection layer 36b may have a thickness of about 20 nm to about 100 nm.

An upper electrode 40 may be formed on the organic emission layer 30. The upper electrode 40 may include a conductive material having a lower work function than the lower electrode 20. According to an embodiment, the upper electrode 40 may include a translucent or highly reflective conductive material. The upper electrode 40 is a metal electrode including, for example, aluminum (Al), gold (Au), silver (Ag), iridium (Ir), molybdenum, palladium (Pd), or platinum (Pt). Can be As another example, the upper electrode 40 may be a transparent oxide electrode including indum tin oxide (ITO) or indium zinc oxide (IZO), or a carbon-based transparent electrode including graphene.

When the upper electrode 40 is a metal electrode, surface plasmon absorption may occur considerably when light passes through the upper electrode 40. Therefore, in this case, it is possible to increase the light extraction efficiency by minimizing the absorption of surface plasmon. To this end, a light scattering layer 70 to be described later may be applied. Further, when the upper electrode 40 is a transparent electrode, since the density of free electrons in the electrode is greatly reduced, generation of surface plasmon polaritons may be greatly reduced, and thus surface plasmon absorption may be reduced. However, due to the difference in refractive index between the transparent electrode and the outside air, photons cannot be emitted to the outside and may be trapped in the upper electrode 40 in most of the waveguide mode. Therefore, even in this case, light can be extracted to the outside by using the light scattering layer 70 to be described later.

The upper electrode 40 may have a thickness of about 10 nm to about 60 nm. According to an embodiment, an interval between the upper surface of the light emitting layer 34 and the upper electrode 40 may be about 30 nm to about 160 nm.

A buffer layer 50 may be formed on the upper electrode 40. The buffer layer 50 may be formed using thermal evaporation and/or facing target sputtering at a low temperature of 20°C to 100°C.

The thermal evaporation method melts and vaporizes a dielectric material using an electron beam or an electric filament in a high vacuum (5×10 ^-5 torr to 1×10 ^-7 torr), and then deposits the vaporized dielectric material on the upper electrode 40. That's how to do it. The temperature at which the dielectric material is vaporized may be maintained below about 100°C. The counter target sputtering method is a method of arranging the upper electrode 40 at a vertical position between two targets facing each other and the targets, and forming the buffer layer 50 on the upper electrode 40 to be. The counter target sputtering method may suppress damage to the organic emission layer 30 adjacent to the upper electrode 40 than a general sputtering deposition method in which a thin film is deposited while the deposition substrate and the target face each other.

The buffer layer 50 may be formed using an inorganic compound having a refractive index of 1.8 or more for light having a wavelength of 550 nm. For example, the buffer layer 50 may include WO ₃ , ZnO, SnO ₂ , TiO ₂ , indium tin oxide (ITO), or indium zinc oxide (IZO). The buffer layer 50 may have a thickness of about 50 nm to 200. Furthermore, the buffer layer 50 may be a thin film having a visible light transmittance of 80% or more.

When the upper electrode 40 is a metal electrode, the buffer layer 50 may serve to induce coupling of the surface plasmon polaritone. When the upper electrode 40 is a transparent oxide electrode, the buffer layer 50 forms a waveguide mode in the upper electrode 40 and the organic emission layer 30 below it, so that light is not isolated. It can play a role of spreading the field. The buffer layer 50 may provide a surface on which polygonal light scattering crystals 72 to be described later can be easily formed. Furthermore, the buffer layer 50 may prevent some of the chemical components of the light scattering crystals 72 from being diffused into the organic emission layer 30.

After forming the buffer layer 50 and before forming the nuclear layer 60 to be described later, a weak surface plasma treatment and/or a surface gas treatment may be additionally performed. Through the treatment processes, the surface energy of the buffer layer 50 may be changed.

The nuclear layer 60 may be formed on the buffer layer 50. The nuclear layer 60 may help form light-scattering crystals 72 to be described later, and may also play a role of adjusting the size of the light-scattering crystals 72. The nuclear layer 60 may be formed using a thermal evaporation method and/or a counter target sputtering method at a low temperature of 20°C to 100°C. The nuclear layer 60 may be formed of a material having a surface energy different from that of the buffer layer 50. For example, the nuclear layer 60 may include AgCl, BaCl ₂ , ZnS, ZnSe, ZnCl ₂ , LiF or LiCl. The nuclear layer 60 may be thinly formed to have a thickness of 5 nm or more and 100 nm or less.

A light scattering layer 70 may be formed on the nuclear layer 60. The light scattering layer 70 may include a plurality of polygonal light scattering crystals 72. The light scattering layer 70 may perform a role of scattering light guided out of the upper electrode 40 through the light scattering crystals 72 and extracting the light to the outside. Specifically, the light scattering crystals 72 may be a nanostructure aggregate having an irregular polygonal pyramid shape. For example, the light scattering crystals 72 may have a width of 150 nm to 1 μm and a height of 150 nm to 1 μm. The light scattering crystals 72 may have a height/width ratio of 0.5 or more. The light scattering crystals 72 may have a refractive index of 1.75 or more for light having a wavelength of 550 nm, and may have a visible light transmittance of 80% or more. For example, the light scattering crystals 72 may include AgCl, BaCl ₂ , MgO, ZnO, SnO2, ZnS, or ZnSe.

The light scattering layer 70 may be formed by depositing a dielectric material using a thermal evaporation method and/or a counter target sputtering method at a low temperature of 20°C to 100°C. The light scattering crystals 72 may be formed from the nuclear layer 60 through anisotropic growth. That is, since the light-scattering crystals 72 are formed at different speeds of crystal growth depending on a direction, as a result, the light-scattering crystals 72 may have a shape such that a plurality of polygonal pyramids are densely formed. Accordingly, the light scattering layer 70 may have a rough surface.

According to an embodiment, the buffer layer 50, the nuclear layer 60, and the light scattering layer 70 on the upper electrode 40 may all be formed using low-temperature deposition methods. In particular, the thermal evaporation method or the counter target sputtering method described above may be performed at a lower deposition temperature and conditions close to atmospheric pressure compared to other deposition methods. Accordingly, when the buffer layer 50, the nuclear layer 60, and the light scattering layer 70 are formed on the upper electrode 40, damage to the organic emission layer 30 can be minimized.

Light emitted from the organic emission layer 30 may be absorbed and lost by the upper electrode 40 due to a surface plasmon effect caused by the upper electrode 40 (eg, a metal electrode). The loss of light due to the surface plasmon effect is largely influenced by the thickness of the electron transport layer 22a and/or the electron injection layer 22b. In order to suppress absorption of light by the upper electrode 40, the electron transport layer 22a and/or the electron injection layer 22b may be thickened. However, when the thickness of the electron transport layer 22a and/or the electron injection layer 22b is increased, the electron injection efficiency of the electron transport layer 22a and/or the electron injection layer 22b decreases, resulting in luminous efficiency. Is reduced.

On the other hand, when the thickness of the upper electrode 40 is sufficiently thin and a transparent dielectric layer having a high refractive index is present on the upper electrode 40, the surface plasmon polariton can be coupled to the outside of the upper electrode 40. have. Accordingly, light may be transferred to the dielectric layer and the light may be emitted outside the upper electrode 40.

However, it may be difficult to increase the light extraction efficiency of the organic light emitting diode simply by forming the dielectric layer having a high refractive index on the upper electrode 40. That is, the ebanescent field is formed due to the dielectric layer, but since the difference between the refractive index of the dielectric layer and the external air is large, the waveguide mode and the surface plasmon polariton are formed in the dielectric layer, and less light is emitted to the outside air. I can. In order to emit light coupled to the dielectric layer to the outside, the surface (a surface in contact with air) may be roughened by forming an appropriate light extraction structure on the surface of the dielectric layer. When the surface of the dielectric layer becomes rough, light coupled into the dielectric layer does not form a waveguide mode and is scattered in all directions by the rough surface, thereby increasing light extraction efficiency.

According to an embodiment, the buffer layer 50, the nuclear layer 60, and the light scattering layer 70 formed on the upper electrode 40 may constitute the dielectric layer. As a result, the surface plasmon plaitone can be coupled to the outside of the upper electrode 40 and released to the outside. Accordingly, it is possible to prevent light from being absorbed by the upper electrode 40 by the surface plasmon. In addition, since the light scattering layer 70 may have a rough surface through the light scattering crystals 72, a waveguide mode may not be formed in the light scattering layer 70. Light may be scattered through the light-scattering crystals 72 and emitted to the outside of the light-scattering layer 70. Accordingly, light is emitted to the outside of the organic light emitting diode without loss, thereby improving light extraction efficiency.

Example 2

2 is a cross-sectional view of an organic light emitting diode according to another embodiment of the present invention. For the sake of brevity, the same reference numerals are used for components that are substantially the same as those of the embodiment described above with reference to FIG. 1, and descriptions of the components may be omitted.

Referring to FIG. 2, a nuclear layer 60 including a plurality of nuclear particles 62 may be formed on the buffer layer 50. The nuclear particles 62 may be formed in an island shape on the buffer layer 50 (see FIG. 4A). According to an embodiment, the nuclear particles 62 may be spaced apart from each other in an island shape and uniformly dispersed on the surface of the buffer layer 50. Each of the nuclear particles 62 may have a diameter of 500 nm or less. In addition, a detailed description of the nuclear layer 60 is as described above with reference to FIG. 1.

A light scattering layer 70 including a plurality of light scattering crystals 72 may be formed on the nuclear layer 60. Specifically, the light scattering crystals 72 may be formed through anisotropic growth based on the nuclear particles 62. Since the light-scattering crystals 72 are respectively grown on the nuclear particles 62 dispersed in an island shape, the light-scattering crystals 72 may have a more well-developed polygonal pyramid shape. That is, the light scattering layer 70 may have a high surface roughness through the dense polygonal pyramid-shaped light scattering crystals 72. Since the light scattering layer 70 has a high surface roughness, light scattering may be increased to further improve light extraction efficiency of the organic light emitting diode. In addition, a detailed description of the light scattering layer 70 is as described above with reference to FIG. 1.

Experimental example One: FDTD Computational simulation Light scattering Nanostructure experiment of crystals 72

The degree of improvement of the light extraction efficiency of the organic light emitting diode through the light scattering crystals 72 according to the embodiments of the present invention was confirmed through FDTD computational simulation as follows.

First, sequentially stacked lower electrode: Al 100nm/ Organic light emitting layer: Alq3 240nm/ Upper electrode: Ag 20nm/ Photocoupling layer: TCTA (4,4',4"-tris (N-carbazolyl) 60nm/ Light scattering crystals : The AgCl pyramid structure was used as an OLED structure model The light scattering crystals (AgCl pyramid structure) were set to have a height/width ratio of 1.0 to make the width and height equal to the height of the light scattering crystals at 150 nm, 300 nm and 500 nm, respectively. Computational simulation was performed.

In the modeled OLED device, a dipole light source in the x, y, z axis directions is inserted at a position of 60 nm below the upper electrode, and a power (electric field intensity square) monitor is placed at a position of about 500 nm above the light scattering crystals. After installation, FDTD calculation was performed. The electric field power distribution result collected in the monitor was calculated based on the far-field condition to calculate the power distribution of light emitted to the top of the OLED element. Compared with the OLED device model to which the light scattering crystals are not applied, it was confirmed that the OLED device according to the present embodiments emits higher power. The results are summarized in Table 1 below.

Height of AgCl light scattering crystals None (control) 150nm 300nm 500nm E ² intensity 4.87e-9 5.37e-9 1.01e-8 1.1e-8 Increased light extraction efficiency compared to the control group (%) 10% 107% 126%

As can be seen in Table 1, when the light-scattering crystals according to the present invention have a width and height of 150 nm or more, it can be seen that the light-scattering crystals can have significantly higher light extraction efficiency compared to non-applied OLED devices.

Experimental example 2: Thermal evaporation method by Light scattering Crystals manufacturing experiment

In forming the light scattering crystals according to the embodiments of the present invention, conditions in which polygonal structures can be better formed were confirmed as follows.

3 shows an SEM photograph of a light scattering layer (AgCl 500nm thin film) formed directly on a glass substrate by using a thermal evaporation method at room temperature. Referring to FIG. 3, it can be seen that the size of the light scattering crystals constituting the light scattering layer is as small as 100 nm to 200 nm. Furthermore, the height of the portions of the light scattering crystals protruding onto the surface is also as low as 100 nm. In this way, when AgCl is deposited on an amorphous surface or on a surface of a metal thin film, a relatively flat surface is formed, so that an increase in light extraction efficiency may be insignificant.

4A shows an SEM photograph of a nuclear layer formed on a glass substrate by using a thermal evaporation method at room temperature. Specifically, a 100 nm WO ₃ buffer layer and an 80 nm LiF nuclear layer may be sequentially deposited on a glass substrate at room temperature. Referring to FIG. 4, it can be seen that LiF nuclei particles having a width of 200 nm to 300 nm are separated from each other to form an island shape on a _{dense WO 3 thin film.}

4B shows an SEM photograph of a light scattering layer formed on a nuclear layer by using a thermal evaporation method at room temperature. The nuclear particles described above with reference to FIG. 4A may serve as growth nuclei for the growth of light scattering crystals constituting the light scattering layer. The nuclear particles dispersed in the form of islands on the WO3 buffer layer may adjust the size and height/width ratio of the light scattering crystals according to their distribution. Furthermore, the nuclear particles may adjust the surface roughness of the light scattering layer. Specifically, referring to FIG. 4B, an AgCl light scattering layer was grown on the nuclear layer to a thickness of 600 nm. That is, it is possible to form an irregular polygonal pyramid-shaped nanostructure having a width of 150 nm to 1 μm and a height of 150 nm to less than 1 μm on the upper electrode of the OLED by only the thermal evaporation method at room temperature without using high temperature conditions.

In the above, embodiments of the present invention have been described with reference to the accompanying drawings, but those of ordinary skill in the art to which the present invention pertains can be implemented in other specific forms without changing the technical spirit or essential features. You can understand that there is. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not limiting.

Claims (10)

A lower electrode, an organic emission layer, and an upper electrode sequentially stacked on the substrate;
A buffer layer including a dielectric material on the upper electrode;
A nuclear layer formed of a material having a surface energy different from that of the buffer layer on the buffer layer; And
On the nuclear layer, including a light scattering layer including a plurality of polygonal light scattering crystals anisotropically grown from the nuclear layer,
The nuclear layer includes a plurality of nuclear particles,
The nuclear particles are formed in an island shape on the buffer layer,
The light scattering crystals are grown from the nuclear particles,
Each of the light scattering crystals is an organic light emitting diode having a width of 150nm to 1μm and a height of 150nm to 1μm. The method of claim 1,
Each of the light scattering crystals is an organic light emitting diode having a height of 150nm to 500nm.
The method of claim 1,
The nuclear layer is an organic light emitting diode comprising _{AgCl, BaCl 2} , ZnS, ZnSe, ZnCl _{2, LiF or LiCl.}
The method of claim 1,
The light-scattering crystals are AgCl, BaCl ₂ , MgO, ZnO, SnO ₂ , an organic light emitting diode comprising ZnS or ZnSe.
delete The method of claim 1,
The organic light emitting layer includes a hole injection layer, a hole transport layer, an emission layer, an electron transport layer, and an electron injection layer sequentially stacked on the lower electrode.
Sequentially forming a lower electrode, an organic emission layer, and an upper electrode on a substrate;
Forming a buffer layer including a dielectric material on the upper electrode;
Forming a nuclear layer on the buffer layer of a material having a surface energy different from that of the buffer layer; And
Including the step of anisotropically growing a plurality of polygonal light scattering crystals from the nuclear layer to form a light scattering layer,
The forming of the nuclear layer includes forming a plurality of island-shaped nuclear particles on the buffer layer,
The light scattering crystals are grown from the nuclear particles,
Each of the light scattering crystals has a width of 150 nm to 1 μm and a height of 150 nm to 1 μm.
The method of claim 7,
The forming of the nuclear layer includes performing thermal evaporation or facing target sputtering at a temperature of the substrate of 20°C to 100°C.
The method of claim 7,
The forming of the light scattering layer includes performing a thermal evaporation method or a counter target sputtering method at a temperature of the substrate of 20°C to 100°C.
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