KR101961355B1 - Organic Light Emitting Device - Google Patents

Abstract

An organic light emitting device according to the present invention includes a substrate, a first electrode formed on the substrate, an organic light emitting layer formed on the first electrode, the organic light emitting layer including a light emitting layer that generates light of a wavelength of 450 nm or more and 500 nm or less, And a quantum dot layer formed on a path through which the light generated in the light emitting layer is emitted to the outside and converting the light generated in the light emitting layer into a dark blue color having a wavelength of 430 nm or more and less than 450 nm.
Therefore, according to the embodiments of the present invention, a light emitting layer is formed so as to emit light of a relatively high luminous efficiency and a relatively long lifetime, not a deep blue light having a low luminous efficiency and a short life span, and a quantum dot layer is formed on the light emitting path, It is possible to manufacture an organic light emitting device having a high light emitting efficiency. That is, it is possible to provide an organic light emitting device having higher efficiency than the conventional deep blue light emitting organic light emitting device, and the lifetime can be improved as compared with the conventional one.

Description

[0001] The present invention relates to an organic light-

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic light emitting device, and more particularly, to an organic light emitting device capable of improving light emitting efficiency and lifetime.

An organic light emitting device (OLED) has a structure in which an organic layer including a light emitting layer made of an organic light emitting material is formed between a pair of electrodes, at least one of which is transparent or translucent. That is, the organic light emitting device has a structure in which an anode, an organic layer including a light emitting layer, and a cathode are laminated on a substrate. According to this organic light emitting device, when a voltage is applied between a pair of electrodes (anode and cathode), electrons injected from the cathode and holes injected from the anode meet and recombine in the light emitting layer. The organic light emitting material of the light emitting layer is excited by the generated energy to emit light, and light of various colors such as blue, green, and red is emitted depending on the material of the light emitting layer.

On the other hand, as the screen of the display is progressing in the direction of enlargement, the material of the organic light emitting device is required to be more delicate and sharper colors. Among them, the problems to be solved and the materials to be solved are blue, and high performance light emitting materials are required in the direction from present sky blue to dark blue.

However, in the case of the light emitting layer, the light emitting efficiency and lifetime tends to decrease as the color of short wavelength is emitted. Particularly, the light emitting layer which emits blue light has a problem of low luminous efficiency and long life due to its material characteristics.

Therefore, it is required to develop an organic light emitting device capable of improving light emitting efficiency and lifetime while emitting a dark blue color.

Korean Patent Publication No. 10-2009-0059486

The present invention provides an organic light emitting device having improved luminous efficiency and service life.

The present invention provides an organic light emitting device having improved light emitting efficiency and lifetime while emitting light of a dark blue color.

An organic light emitting device according to the present invention includes: a substrate; A first electrode formed on the substrate; An organic light emitting layer formed on the first electrode, the organic light emitting layer including a light emitting layer emitting light of a sky color of 450 nm or more and 500 nm or less; A second electrode formed on the organic light emitting layer; And a quantum dot layer formed on a path through which the light generated in the light emitting layer is emitted to the outside and converting the light generated in the light emitting layer into a dark blue color having a wavelength of 430 nm or more and less than 450 nm;

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The quantum dot layer may be formed between the first electrode and the organic light emitting layer.

The quantum dot layer may be formed between the first electrode and the substrate.

The quantum dot layer has an emission spectrum of 400 nm or more and 460 nm or less, and an absorption spectrum of 230 nm or more and 480 nm or less.

The quantum dot layer preferably has a thickness of 10 nm to 50 nm.

The quantum dot layer may be formed of a material selected from the group consisting of Mg, Cd, Ti, Li, Cu, Al, Ni, Y, Ag, Mn, V, Fe, La, Ta, Nb, Ga, In, S, Se, Cr, B, N, Sb, and H is sprayed onto the substrate.

According to the embodiment of the present invention, a light emitting layer is formed so as to emit light of a relatively high luminous efficiency and a relatively long lifetime, rather than a deep blue color having a low luminous efficiency and a short life span. By forming a quantum dot layer on a light emitting path, It is possible to manufacture an organic light emitting device having a high light emitting efficiency. That is, it is possible to provide an organic light emitting device having higher efficiency than the conventional deep blue light emitting organic light emitting device, and the lifetime can be improved as compared with the conventional one.

1 is a block diagram of an organic light emitting device according to an embodiment of the present invention.
2 is a block diagram of an organic light emitting device according to a modification of the embodiment
3 is a view showing an organic light emitting layer according to an embodiment of the present invention,

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be understood, however, that the invention is not limited to the disclosed embodiments, but is capable of other various forms of implementation, and that these embodiments are provided so that this disclosure will be thorough and complete, It is provided to let you know completely.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic light emitting device (OLED), and more particularly, to an organic light emitting device that emits a deep blue light. Further, the present invention provides an organic light emitting device which can emit a dark blue color and improve its luminous efficiency and lifetime compared to the conventional art. The present invention also provides an organic light emitting device capable of converting light emitted from a light emitting layer to emit light to the outside.

Hereinafter, an organic light emitting device according to an embodiment of the present invention will be described with reference to FIGS. 1 to 3. FIG.

1 is a block diagram of an organic light emitting device according to an embodiment of the present invention. 2 is a block diagram showing an organic light emitting device according to a modification of the embodiment. FIG. 3 is a diagram showing an organic light emitting layer according to an embodiment of the present invention.

Referring to FIG. 1, an organic light emitting device according to an embodiment of the present invention includes a substrate 100, a first electrode 200 formed on the substrate 100, an organic material formed on the first electrode 200 An organic light emitting layer 400 including a light emitting layer 430 for emitting light, a second electrode 500 formed on the organic light emitting layer 400, a light emitting layer 430 for emitting light, And a quantum dot layer 300 formed on the quantum dot layer 300.

Hereinafter, each configuration of the organic light emitting device according to the embodiment of the present invention will be described.

The substrate 100 is formed of a light transmissive or translucent material so that light generated in the organic light emitting layer 400 can be transmitted and emitted to the outside. For example, the substrate 100 may be any one of glass having a light transmittance of 80% or more, plastic including at least one of PE, PES, and PEN, or a film having flexibility.

The first electrode is formed on the upper surface of the substrate 100 and functions as a positive electrode. For this purpose, the first electrode 200 uses a material having a high work function, for example, a work function of 4.5 eV or more, so as to smoothly transfer holes to the organic light emitting layer 400. The organic light emitting device according to the embodiment is formed of a material having a light transmitting property so that the light generated in the organic light emitting layer 400 can be emitted to the outside through the first electrode 200 and the substrate 100. The first electrode 200 may be formed by depositing a transparent conductive material such as indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), or In ₂ O ₃ through a sputtering process. Of course, the first electrode 200 may be formed by applying various deposition processes in addition to the sputtering process according to the transparent conductive material.

The second electrode 500 is formed on the organic light emitting layer 400 and functions as a cathode for providing electrons to the organic light emitting layer 400. The second electrode 500 preferably has a low work function, for example, a material having a work function of 4.0 eV or less so that electrons can be injected smoothly into the organic light emitting layer 400. The organic light emitting device according to the exemplary embodiment of the present invention may be configured such that the light generated in the organic light emitting layer 400 is emitted to the outside through the first electrode 200 and the substrate 100, The second electrode 500 is formed so as to have a reflection characteristic so as to be reflected by the second electrode 500 and to be directed in a direction in which the first electrode 200 is positioned. The second electrode 500 may be formed of any one of Al, Ca, LiF-Al, LiF-Ca, Mg, Ag, Ca-Ag and Mg-Ag by a thermal deposition process.

The first electrode 200 is formed to have a light transmitting property and the second electrode 500 is formed to reflect light so that light generated in the organic light emitting layer 400 is incident on the first electrode 200 and the substrate 200, And the light is emitted to the outside.

However, the present invention is not limited to this, and the second electrode 500 may have a light-transmitting property and the second electrode 500 may be formed to be capable of reflecting light.

The organic light emitting layer 400 is a layer formed between the first electrode 200 and the second electrode 500 and includes a plurality of layers. The organic light emitting layer 400 according to the embodiment may be formed on the quantum dot layer 300 between the first electrode 200 and the second electrode 500 as shown in FIG. But may also be formed on the first electrode 200 as shown in FIG.

3, the organic light emitting layer 400 includes a hole injection layer 410, a hole transport layer 420 formed on the hole injection layer 410, a light emitting layer 430 formed on the hole transport layer 420, An electron transport layer 440 formed on the light emitting layer 430, and an electron injection layer 450 formed on the electron transport layer 440. Of course, the organic light emitting layer 400 is not limited to the structure described above, and at least one of the layers may be excluded, or an electron blocking layer and a charge generating layer may be further included.

The organic light emitting layer 400 according to the embodiment may be formed by any one of thermal evaporation and solution process.

The material of each layer may be different when the organic light emitting layer 400 is formed by a thermal evaporation method or by a solution process.

For example, when the organic light emitting layer 400 is formed by thermal evaporation, the hole injection layer 410 may be formed of, for example, HAT-CN, the hole transport layer 420 may be formed of TAPC and the electron transport layer 440 may be formed of, TPYMB, and the electron injection layer 450 may be formed of LiF. Of course, the hole injecting layer, the hole transporting layer, the electron transporting layer, and the electron injecting layer are not limited to the above materials, and various materials capable of performing each function can be applied.

The light emitting layer 430 according to the embodiment may be formed by doping FCP with a dopant such as mCP to a host mCP, which emits blue light having a wavelength of 450 nm or more and 500 nm or less. Of course, the light emitting layer 430 is not limited to the above-described materials, and various materials capable of generating blue light having a wavelength of 450 nm or more and 500 nm or less can be applied.

The organic light emitting layer 400 is not limited to the thermal evaporation method described above, but may be formed by a solution process. In addition, some of the organic light emitting layer 400 may be formed by a solution process and others may be formed by thermal evaporation.

For example, when a part of the organic luminescent layer 400 is formed by a solution process and the other part is formed by thermal evaporation, the organic luminescent layer 400 may be formed of a hole transport layer 420, a light emitting layer 430 and an electron transport layer 440). The hole transport layer 420 and the light emitting layer 430 may be formed by a solution process, and the electron transport layer 440 may be formed by a thermal deposition process. The hole transport layer 420 may be formed by applying a solution of Poly-TPD and a solvent on the first electrode 200. The light emitting layer 430 may be formed of a layer emitting light of a wavelength of 450 nm or more and 500 nm or less , A solution in which a host mcp and a dopant firpic are dissolved in a solvent can be coated. Of course, the light emitting layer 430 is not limited to the above-described materials, and various materials capable of generating light having a wavelength of 450 nm or more and 500 nm or less can be applied.

The solvent for forming the hole transport layer 420 and the light emitting layer 430 by a solution process may be any one of toluene and chlorobenzene.

The present invention is an organic light emitting device that emits or emits light of a dark blue color, more specifically, a light having a wavelength of 430 nm or more and less than 450 nm.

However, as described above, the light emitting layer 430 according to the embodiment is a layer that generates light of more than 450 nm and less than 500 nm, more specifically, of sky blue. In order to allow the light of wavelengths of 430 nm or more and less than 450 nm to be emitted to the outside of the glass light emitting device, in the embodiment of the present invention, the color of light of 450 nm or more and 500 nm or less of blue light generated in the light emitting layer 430 is 430 nm or more and 450 nm or less And is discharged to the outside.

For this purpose, the quantum dot layer 300 is formed in a direction in which light generated in the light emitting layer 430 is emitted to the outside, that is, a path that moves toward the first electrode 200 or the substrate 100. 1, a quantum dot layer 300 is formed between the first electrode 200 and the organic light emitting layer 400, more specifically between the first electrode 200 and the hole injection layer 410, . The formation position of the quantum dot layer 300 is not limited to the area between the first electrode 200 and the organic emission layer 400 but may be a range in which light generated in the emission layer 430 is emitted to the outside of the substrate Or may be between the first electrode 200, which is another position of the path, and the substrate 100.

The quantum dot layer 300 may be formed by coating a solution prepared by dispersing a quantum dot (QD) of several nanometers (nm) which emits light into a dispersion solvent such as toluene itself. The quantum dot may be a colloidal particle, The colloidal particles may be selected from the group consisting of Mg, Cd, Ti, Li, Cu, Al, Ni, Y, Ag, Mn, V, Fe, La, Ta, Nb, Ga, In, S, Se, , N, Sb, H, and combinations of two or more thereof.

The quantum dot layer 300 serves to convert blue light having a wavelength of 450 nm or more and 500 nm or less to a dark blue color having a wavelength of 430 nm or more and less than 450 nm as described above. It is preferable that the quantum dot layer 300 emits light of 400 nm or more and 460 nm or less while its absorption spectrum is overlapped at least partially with the photoluminescence of the light emitting layer 430.

The spectrum (i.e., emission spectrum) of the light generated in the quantum dot layer 300 and the absorption spectrum can be controlled by controlling quantum dots, that is, the material and particle size of the colloidal particles. That is, the quantum dot layer 300 having an emission spectrum of 400 nm or more and 460 nm or less and an absorption spectrum of 230 nm or more and 480 nm or less can be formed by controlling the material of the selected colloidal particles and the particle size thereof.

In addition, the quantum dot layer 300 according to the embodiment of the present invention is formed to have a thickness of 10 nm to 50 nm, and the quantum dot layer 300 may have a thickness of 430 nm or more and less than 450 nm So that it can be converted into dark blue light.

When the thickness of the quantum dot layer 300 is less than 10 nm, it may not be easy to convert into light having a wavelength of 430 nm or more and less than 450 nm when blue light having a wavelength of 450 nm or more and 500 nm or less passes through the quantum dot layer 300. That is, the color of the light emitted to the outside of the organic light emitting device may not be 430 nm or more and dark blue having a wavelength of less than 450 nm. Conversely, when the thickness of the quantum dot layer 300 exceeds 50 nm, the resistance may be high and the efficiency of the organic light emitting device may decrease.

Therefore, in the embodiment of the present invention, the quantum dot layer 300 is formed with a thickness of 10 nm to 50 nm.

When the quantum dot layer 300 is formed, the blue light having a wavelength of 450 nm or more and 500 nm or less generated in the light emitting layer 430 is moved toward the outside of the substrate 100 and passes through the quantum dot layer 300 formed on the path Is converted into a dark blue color having a wavelength of 430 nm or more and less than 450 nm, and this light is emitted to the outside.

1, blue light having a wavelength of 450 nm or more and 500 nm or less generated in the light emitting layer 430 passes through the quantum dot layer 300 through the hole transport layer 420 and the hole injection layer 410, And the converted light is emitted to the outside through the first electrode 200 and the substrate 100. [ 2, a blue light having a wavelength of 450 nm or more and 500 nm or less generated in the light emitting layer 430 is incident on the hole transport layer 420, the hole injection layer 410, the first electrode 200, And is converted into a dark blue color having a wavelength of 430 nm or more and less than 450 nm while passing through the quantum dot layer 300, and the converted light is emitted to the outside through the substrate 100.

Therefore, according to the embodiment of the present invention, a light emitting layer is formed so as to emit light of a relatively high luminous efficiency and a relatively long lifetime instead of a deep blue color having a low luminous efficiency and a short life span, and a quantum dot layer is formed on the light emitting path, It is possible to manufacture an organic light emitting device having high luminous efficiency while emitting light. That is, it is possible to provide an organic light emitting device having higher efficiency than the conventional deep blue light emitting organic light emitting device, and the lifetime can be improved as compared with the conventional one.

100: substrate 200: first electrode
300: quantum dot layer 400: organic light emitting layer
500: Second electrode

Claims (6)

Board;
A first electrode formed on the substrate;
An organic light emitting layer formed on the first electrode, the organic light emitting layer including a light emitting layer generating blue light having a wavelength of 450 nm or more and 500 nm or less;
A second electrode formed on the organic light emitting layer; And
A quantum dot layer formed on a path through which light generated in the light emitting layer is emitted to the outside and converting the light generated in the light emitting layer into a dark blue color having a wavelength of 430 nm or more and less than 450 nm;
/ RTI >
The light emitting layer is formed by doping a host mCP with dopant Firpic,
Wherein the quantum dot layer has a thickness of 10 nm to 50 nm. The method according to claim 1,
Wherein the quantum dot layer is formed between the first electrode and the organic light emitting layer. The method according to claim 1,
Wherein the quantum dot layer is formed between the first electrode and the substrate. The method according to any one of claims 1 to 3,
Wherein the quantum dot layer has an emission spectrum of 400 nm or more and 460 nm or less, and an absorption spectrum of 230 nm or more and 480 nm or less. delete The method of claim 4,
The quantum dot layer may be formed of a material selected from the group consisting of Mg, Cd, Ti, Li, Cu, Al, Ni, Y, Ag, Mn, V, Fe, La, Ta, Nb, Ga, In, S, Se, Wherein at least one of Cr, B, N, Sb and H is dispersed to form a coating.

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