KR101318745B1 - Organic Electro Luminescence Display Device And Fabricating Method Thereof - Google Patents

Abstract

The present invention relates to an organic light emitting display device and a method of manufacturing the same.

The organic light emitting layer of the organic electroluminescent display device of the present invention comprises a hole related layer formed on the first electrode; An electron related layer positioned below the second electrode; The light emitting layer is disposed between the hole related layer and the electron related layer and is interspersed with inorganic nanoparticles. The inorganic nanoparticles include any one of SiO ₂ , TiO ₄ , and ZnO. The inorganic nanoparticles are added to the light emitting layer in a weight ratio of 0.1 to 5 wt%. Each of the inorganic nanoparticles has a diameter between 1 and 10 nm.

Description

Organic electroluminescent display device and manufacturing method thereof {Organic Electro Luminescence Display Device And Fabricating Method Thereof}

1 is a view showing one organic light emitting cell and a light emitting principle of a conventional organic electroluminescent display device.

2 is a diagram schematically illustrating a movement path of electrons and holes in a conventional light emitting layer.

3 is a view showing an organic electroluminescent display device according to the present invention.

4 is a view illustrating in detail one organic light emitting cell and a light emitting layer of FIG. 3.

FIG. 5 is a diagram schematically illustrating a shape in which electrons and holes are introduced around nanoparticles of an insulating material. FIG.

FIG. 6 is a view schematically illustrating a shape in which electrons and holes are introduced around metal nanoparticles. FIG.

7 is a view schematically illustrating the light emission phenomenon in the light emitting layer in the present invention.

8 is a flowchart illustrating a method of manufacturing an organic light emitting display device according to the present invention in stages.

        <Explanation of symbols for the main parts of the drawings>

2,102 substrate 4,104 first electrode (anode electrode)

10,110: organic light emitting layer 12,112: second electrode (cathode electrode)

180: inorganic nanoparticles 128: packaging plate

126: sealant 114; Thin film transistor array unit

172: getter 10a, 110a: electron injection layer

10b, 110b: electron transport layer 10c, 110c: light emitting layer

10d, 110d: hole transport layer 10e, 110e: hole injection layer

The present invention relates to an organic electroluminescent device, and more particularly, to an organic electroluminescent display device capable of improving luminous efficiency and a method of manufacturing the same.

2. Description of the Related Art In recent years, various flat panel display devices capable of reducing weight and volume, which are disadvantages of a cathode ray tube (CRT), have been developed. Such flat panel displays include liquid crystal displays (hereinafter referred to as "LCDs"), field emission displays (FEDs), plasma display panels (hereinafter referred to as PDPs), and electroluminescence. Nessence ("EL") display devices, etc. There are active researches to improve the display quality of such a flat panel display device and attempt to enlarge the screen.

Among these PDPs, PDPs are attracting attention as a display device that is most advantageous for large screen size but large screen size because of simple structure and manufacturing process, but it has disadvantage of low luminous efficiency, low luminance and high power consumption. On the other hand, an active matrix LCD having a thin film transistor (hereinafter referred to as a TFT) as a switching element has a disadvantage in that it is difficult to large screen due to the semiconductor process and consumes a lot of power due to the backlight unit. , Optical prism sheet, diffusion plate, etc. are characterized by high optical loss and narrow viewing angle.

On the other hand, EL devices are classified into inorganic electroluminescent devices and organic electroluminescent devices according to the material of the light emitting layer. The EL devices are self-luminous devices that emit light by themselves, and have a high response speed and high luminous efficiency, luminance, and viewing angle. In comparison with the organic light emitting device, the inorganic light emitting device has a high power consumption and cannot obtain high luminance, and cannot emit various colors of R, G, and B. On the other hand, the organic light emitting diode is driven at a low DC voltage of several tens of volts, has a fast response speed, obtains high luminance, and emits various colors of R, G, and B, which is suitable for next-generation flat panel display devices. .

1 is a view showing the light emission principle of one organic light emitting cell (EL cell) and organic light emitting cell (EL cell) of a conventional organic EL display device.

The organic light emitting cell (EL cell) illustrated in FIG. 1 includes an organic light emitting layer 10 formed between the first electrode (or anode electrode) 4 and the second electrode (or cathode electrode) 12, and the organic light emitting layer The electron injection layer 10a, the electron transport layer 10b, the light emitting layer 10c, the hole transport layer 10d, and the hole injection layer 10e are provided at 10.

The hole injection layer 10e controls the concentration of holes and the hole transport layer 10d controls the movement speed of the holes so that holes generated in the first electrode 4 can be easily injected into the light emitting layer 10c. .

The electron injection layer 10a and the electron transport layer 10b serve to easily inject electrons generated from the second electrode 12 into the light emitting layer 10c by adjusting the concentration and speed of the electrons.

The light emitting layer 10c mainly functions to generate light, but also serves to transport electrons or holes. The light emitting layer 10c may be a light emitting material used alone or a light emitting material doped in a host material.

When a voltage is applied between the first electrode 4 and the second electrode 12 of the organic light emitting cell (EL cell), electrons e ⁻ generated from the second electrode 12 are transferred to the electron injection layer 10a. And a hole H ⁺ generated from the first electrode 4 through the electron transport layer 10b, through the hole injection layer 10d and the hole transport layer 10d. Go to 10c). Accordingly, in the light emitting layer 10c, light is generated by collision and recombination of electrons (e ⁻ ) and holes (H ⁺ ) supplied from the electron transporting layer 10b and the hole transporting layer 10d, and the light is generated by the first electrode. Through (4), it is emitted to the outside and an image is displayed.

On the other hand, the conventional organic light emitting layer 110 is all made of an organic material. The grain boundary formed in the organic materials causes the movement of electrons (e ⁻ ) and holes (H ⁺ ) to be resisted. That is, due to the resistance of the organisms themselves electron (e ^-) a large amount of electron (e ^-), as is the hole (H ⁺⁾ in Fig. 2 by being subjected to resistance and a hole (H ⁺⁾ are unable to recombine with each other Passes through the light emitting layer 10c. Therefore, the luminous efficiency of the organic light emitting cell (EL cell) is reduced.

The present invention provides an organic light emitting display device and a method for manufacturing the same, which can improve luminous efficiency.

The organic light emitting layer of the organic electroluminescent display device of the present invention comprises a hole related layer formed on the first electrode; An electron related layer positioned below the second electrode; The light emitting layer is disposed between the hole related layer and the electron related layer and is interspersed with inorganic nanoparticles.
The inorganic nanoparticles include any one of SiO ₂ , TiO ₄ , and ZnO.
The inorganic nanoparticles are added to the light emitting layer in a weight ratio of 0.1 to 5 wt%.
Each of the inorganic nanoparticles has a diameter between 1 and 10 nm.

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The method of manufacturing the organic electroluminescent display device includes forming a first electrode on a substrate; Forming an organic emission layer on the first electrode; Forming a second electrode on the organic light emitting layer, and forming the organic light emitting layer comprises: forming a hole related layer on the first electrode; Forming a light emitting layer interspersed with inorganic nanoparticles on the hole related layer; Forming an electron related layer on the light emitting layer.

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Other objects and features of the present invention will become apparent from the following description of embodiments with reference to the accompanying drawings.

Hereinafter, preferred embodiments of the present invention will be described with reference to FIGS. 3 to 8. FIG.

3 is a view showing an organic EL device according to the present invention.

The organic EL display device illustrated in FIG. 3 is formed on the thin film transistor (T) array unit 114 formed on the transparent substrate 102 and the thin film transistor (T) array unit 114 and is formed on the organic light emitting cell ( An organic EL array 150 in which the EL cells are arranged in a matrix form is formed. The organic light emitting cell (EL cell) includes a first electrode (or anode electrode) 104, an organic light emitting layer 110, and a second electrode (or cathode electrode) 112.

The organic material of the organic EL array 150 has a property of being easily degraded by moisture and oxygen. In order to solve this problem, an encapsulation process is performed to bond the substrate 102 and the packaging plate 128 on which the organic EL array 150 is formed through the sealant 126.

The packaging plate 128 emits heat generated when the organic EL element emits light and protects the organic EL array 150 from external force or oxygen and moisture in the atmosphere.

The getter 172 is filled in the etched portion after a portion of the packaging plate 128 is etched and fixed by the semipermeable membrane 125.

4 is a cross-sectional view illustrating in detail an organic light emitting cell (EL cell) of the organic EL display device illustrated in FIG. 3.

Referring to FIG. 4, an organic light emitting cell (EL cell) according to the present invention includes an organic light emitting layer 110 formed between a first electrode (or anode electrode) 104 and a second electrode (or cathode electrode) 112. The organic light emitting layer 110 includes an electron injection layer 110a, an electron transport layer 110b, an emission layer 110c to which inorganic nanoparticles 180 are added, a hole transport layer 110d, and a hole injection layer 110e. do.

The hole injection layer 110e controls the concentration of holes and the hole transport layer 110d controls the movement speed of the holes so that holes generated in the first electrode 104 can be easily injected into the light emitting layer 110c. .

The electron injection layer 110a and the electron transport layer 110b serve to easily inject electrons generated from the second electrode 112 into the light emitting layer 110c by adjusting the concentration and speed of the electrons.

The first electrode 104 is formed of a transparent conductive material such as indium tin oxide (ITO), indium zinc oxide (IZO), indium tin zinc oxide (ITZO), and gold (Au), platinum (Pt), and copper (Cu). Etc. may be included.

The hole injection layer 110e is mainly formed by depositing copper phthalocyanine (Copper (II) Phthalocyanine), and is deposited to have a thickness of about 10 to 30 nm.

The hole transport layer 110d is mainly formed by depositing N, N-di (naphthalen-1-yl) -N, N'-diphenylbenzidine (NPD). At this time, the hole transport layer has a thickness of about 30 ~ 60 nm.

The electron transport layer 10b is made of metal complex compounds such as Alq ₃ and is deposited to have a thickness of about 20 to 50 nm.

The electron injection layer 10a is formed by depositing an alkali metal derivative to have a thickness of about 30 to 60 nm.

The light emitting layer 110c mainly functions to generate light, but also serves to transport electrons or holes.

As such, the light emitting layer 110c may use a light emitting material alone or a light emitting material doped in a host material as necessary. For example, it is formed by doping a material such as N-methylquinacridone (MQD) into a host such as tris- (8-hydroxyquinoline aluminum) (Alq ₃ ). In addition, the light emitting layer 110c according to the present invention further includes inorganic nanoparticles 180. Herein, the inorganic nanoparticles 180 are added to the light emitting layer 110c at a weight ratio of about 0.1 to 5wt% when the weight of the light emitting layer 110c is 100wt%, and as shown in FIG. 4, in the light emitting layer 110c. Spread evenly The inorganic nanoparticles 180 increase the recombination rate of electrons and the positive space by promoting recombination between electrons in the first electrode 104 and holes in the second electrode. As a result, the luminous efficiency of the organic light emitting cell can be improved.

This will be described in more detail with reference to FIGS. 5 and 6 as follows.

First, the inorganic nanoparticles 180 of the present invention may be an insulating inorganic material or a metal.

FIG. 5 is a view schematically illustrating that electrons and holes are concentrated around silicon oxide (SiO ₂ ) particles when an inorganic inorganic material silicon oxide (SiO ₂ ) is used as the inorganic nanoparticles 180.

Since silicon oxide (SiO ₂ ) has a predetermined dielectric constant as an inorganic insulating material, electrons (e ⁻ ) and holes (H ⁺ ) may be charged with the silicon oxide (SiO ₂ ) particles interposed therebetween. In the peripheral silicon oxide (SiO ₂₎ particles in accordance with this principle, a large amount of the electron (e ^-) and holes (H ⁺⁾ are able to focus being electron (e ^-), the greater the recombination probability of the hole (H ^+).

FIG. 6 is a view schematically illustrating that electrons (e ⁻ ) holes (H ⁺ ) are concentrated to metal particles when metal particles such as TiO ₄ and ZnO are used as the inorganic nanoparticles 180.

A metal bond is a state in which a cation of a metal atom floats in a sea of free electrons, and functions to bind the whole by the electrostatic attraction between the free electron and the cation. Accordingly, as shown in FIG. 6, a plurality of free electrons (-) and cations (+) are located in the metal particles, as well as the electrostatic attraction between the cations (+) and the electrons (e ⁻ ), and the free electrons ( Electrostatic attraction can act between-) and hole (H ⁺ ). As a result, a large amount of holes and electrons can be concentrated around the metal particles, thereby increasing recombination of electrons (e ⁻ ) holes (H ⁺ ) in the light emitting layer 110c, as shown in FIG. 7. The luminous efficiency of the cell can be improved.

As such, the organic EL display device according to the present invention increases the probability of recombination between electrons (e ⁻ ) and holes (H ⁺ ) as compared to the prior art by scattering inorganic nanoparticles 180 in the light emitting layer 110c. It can be improved.

Hereinafter, a method of manufacturing an organic EL display device according to the present invention will be described with reference to FIG. 8.

First, in an active organic EL display device, a thin film transistor array unit including a signal line, a thin film transistor T, and the like is formed on a substrate (S10).

A metal transparent conductive material is deposited on the substrate 102 on which the thin film transistor (T) array unit 114 is formed using a deposition method such as sputtering using an argon (Ar) plasma, a nozzle coating, a spin coating, a roll printing method, or the like. After that, the first electrode 104 is formed by patterning the photolithography process and the etching process.

Here, at least one of amorphous silicon (a-Si) and polysilicon (Poly-Si) is used for the thin film transistor (T) array unit 114, and ITO (Indium) is used as the transparent conductive material of the first electrode 104. Tin oxide, indium zinc oxide (IZO), and indium tin zinc oxide (ITZO) are formed of a transparent conductive material, and may include gold (Au), platinum (Pt), copper (Cu), and the like.

In the passive organic EL display device, since the thin film transistor array unit 114 is not provided, the first electrode 104 is formed directly on the substrate 102 when the passive organic EL display device is formed.

On the substrate 102 on which the first electrode 104 is formed, hole injection is performed using a vacuum deposition method in the case of a low molecular compound, a nozzle coating, a spin coating, an inkjet printing method, a roll printing method, or the like in the case of a polymer compound. Layers 110e (S32) and hole transport layers 110d (S34), light emitting layers 108c (S36) and electron transport layers 110b (S38) and electron injection layers 110a (to which inorganic nanoparticles 180 are added) ( S40) are sequentially stacked. As a result, the organic light emitting layer 110 is formed on the substrate 102 on which the first electrode 104 is formed.

Herein, when the light emitting material is a low molecular compound, the light emitting layer 108c to which the inorganic nanoparticles 180 are added is provided with the inorganic nanoparticle powder and the light emitting material, respectively, and the inorganic nanoparticles are deposited at the same time using the vacuum deposition method. By evaporating the powder, it is possible to form the light emitting layer 108c interspersed with the inorganic nanoparticles 180.

In addition, when the light emitting material is a high molecular compound, the inorganic nanoparticle powder is mixed with the high molecular compound solution, and then formed by coating, spin coating, inkjet printing, roll printing, or the like.

The inorganic nanoparticles 180 may be formed of an inorganic insulating material such as silicon oxide (SiO ₂ ) or a metal material such as TiO ₄ or ZnO. Each of the inorganic nanoparticles may have a diameter of 1 to 10 nm.

The second electrode 100 is formed by depositing a metal material having a low work function by sputtering or the like on the substrate 102 on which the organic light emitting layer 110 is formed (S50).

Here, Al, Li, Ca, Mg, Ba, etc. may be used as the metal electrode having a low work function.

On the other hand, the light emitting layer (110c) is added to the inorganic nanoparticles 180 to improve the luminous efficiency can be used in the passive organic EL display device, as well as the bottom emission organic EL device, the top emission organic EL device And passive organic EL devices.

As described above, the organic electroluminescent device and the method of manufacturing the same according to the present invention improve the luminous efficiency by increasing the probability of recombination of electrons and constant space as the inorganic nanoparticles are scattered in the light emitting layer.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification, but should be defined by the claims.

Claims (14)

In an organic electroluminescent display device in which organic light emitting cells composed of first and second electrodes positioned on an substrate with an organic light emitting layer interposed therebetween are arranged in a matrix form. The organic light emitting layer is A hole related layer formed on the first electrode; An electron related layer positioned below the second electrode; A light emitting layer interposed between the hole related layer and the electron related layer and interspersed with inorganic nanoparticles, The inorganic nanoparticles include any one of SiO ₂ , TiO ₄ , ZnO, The inorganic nanoparticles are added to the light emitting layer in a weight ratio of 0.1 to 5wt%, And each of the inorganic nanoparticles has a diameter of between 1 and 10 nm. delete delete delete The method of claim 1, And a thin film transistor array unit positioned between the substrate and the organic light emitting cells. The method of claim 1, And the hole related layer is divided into a hole injection layer and a hole transport layer, and the electron related layer is divided into an electron injection layer and an electron transport layer. Forming a first electrode on the substrate; Forming an organic emission layer on the first electrode; Forming a second electrode on the organic light emitting layer, Forming the organic light emitting layer Forming a hole related layer on the first electrode; Forming a light emitting layer interspersed with inorganic nanoparticles on the hole related layer; Forming an electron related layer on the light emitting layer, The inorganic nanoparticles include any one of SiO ₂ , TiO ₄ , ZnO, The inorganic nanoparticles are added to the light emitting layer in a weight ratio of 0.1 to 5wt%, The inorganic nanoparticles each have a diameter of between 1 ~ 10 nm manufacturing method of an organic electroluminescent display device. The method of claim 7, wherein Forming the light emitting layer interspersed with the inorganic nanoparticles is Preparing the inorganic nanoparticle powder; Providing a light emitting material; And depositing the light emitting material on the hole related layer using a vacuum deposition method and simultaneously evaporating inorganic nanoparticle powder on the hole related layer. The method of claim 7, wherein Forming the light emitting layer interspersed with the inorganic nanoparticles is Preparing the inorganic nanoparticle powder; Preparing a light emitting material solution; Mixing the inorganic nanoparticle powder with the light emitting material solution; And coating the light emitting material mixed with the inorganic nanoparticle powder on the hole related layer. delete delete delete The method of claim 7, wherein And forming a thin film transistor array unit positioned between the substrate and the first electrode. The method of claim 7, wherein The hole related layer is divided into a hole injection layer and a hole transport layer, the electron related layer is a method of manufacturing an organic electroluminescent display device, characterized in that divided into an electron injection layer and an electron transport layer.

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