KR101626149B1 - Method for producting organic light emitting diode and apparatus thereof - Google Patents

Abstract

The present invention relates to an apparatus and a method for manufacturing an organic light emitting diode, and more particularly, to a method of manufacturing an organic light emitting diode using a hole injection layer of CuPc, which is a monomolecular series, through thermal deposition of a heterojunction structure using a glass crucible and a flying boat between an anode substrate and a hole transporting layer The ion implantation energy of the hole injection layer of the anode substrate and the hole injection layer of the CuPc are similar to each other. Therefore, the hole injection layer can be easily manufactured, The efficiency of light emission luminance is basically improved on the basis of the injection layer, the interface adhesion force between the anode substrate and the hole transport layer is excellent by the hole injection layer of CuPc, and the HOMO level of the hole injection layer of CuPc is slightly lower than the work function of the anode substrate It is possible to inject holes at a voltage lower than the conventional voltage, and the electrical stability is further improved.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an organic light emitting diode (OLED)

The present invention relates to a method and an apparatus for manufacturing an organic light emitting diode, and in forming an organic light emitting layer between an anode substrate and an anode substrate, a hole injection layer of copper phthalocyanine (CuPc) is formed between the anode substrate and the hole transporting layer of the organic light emitting layer. And more particularly, to an apparatus and method for maximizing luminous efficiency.

In general, organic light-emitting diodes (OLEDs) are used for displays in which holes and electrons injected from an anode substrate and an anode substrate meet an organic light-emitting layer therein and emit light. Organic light emitting devices have been actively developed in the field of BLU (Back Light Unit) of Liquid Crystal Display

In this organic light emitting device, an organic light emitting layer is provided between the anode substrate and the cathode substrate, and the organic light emitting layer is provided in the order of a hole injection layer, a hole transporting layer, and a light emitting layer

Therefore, the hole transport layer has a difference in interface characteristics between the anode substrate and the hole transport layer due to the heterojunction between the anode substrate, which is an inorganic material, and the hole transport layer (TPD), which is an organic material, and the interface characteristics of the hole injection layer There has been a drawback that it is deteriorated. Therefore, in order to improve the interface characteristics of the hole injection layer, the surface energy of the hole injection layer needs to be appropriately increased.

In addition, the energy bandgap difference occurs due to the work function of the anode substrate and the highest occupied molecular orbital (HOMO) level of the hole transport layer. In order to match the energy band gap, the HOMO level should be set between the anode substrate and the hole transport layer. In order to increase the external quantum efficiency, it is necessary to remove the light absorption in the visible light region.

PEDOT: PSS (poly (3,4-ethylenedioxythiophene) poly (styrenesulfonate)), which is a high permeability conductive solution, is used as a typical hole injection layer material, and a hole injection layer of PEDOT: Is formed between the anode substrate and the hole transporting layer.

That is, since the hole injection layer of PEDOT: PSS is formed between the anode substrate and the hole transport layer using a spin coater, there is a problem that the process of manufacturing the hole injection layer is very complicated.

It is an object of the present invention to provide a positive hole injection layer of copper phthalocyanine (CuPc), which is a monomolecular series, by thermal evaporation using a glass crucible and a flying boat on an anode substrate. It is possible to maximize the luminous efficiency and the thermal oxidation and the thermal stability compared with the organic materials of the conventional hole injection layer. Since the ionization energy of the anode and the hole injection layer are similar to each other, the interfacial adhesion with the anode is excellent, The HOMO level of the hole injection layer of CuPc is slightly higher than that of the work function, so that the hole injection can be performed at a voltage lower than that of the conventional voltage, thereby simplifying the manufacturing process of the hole injection layer. .

According to an aspect of the present invention, there is provided an apparatus for fabricating an organic light emitting diode,

An organic light emitting device for emitting light by coupling holes and electrons injected from a cathode substrate and an anode substrate with an organic light emitting material,

The organic light-

A hole transporting layer and a light emitting layer are sequentially formed on the anode substrate,

And a hole injecting layer of a monomolecular type is further formed between the anode substrate and the hole transporting layer.

Here,

An organic material was deposited on the transparent substrate of the electrode material at a predetermined deposition rate and a predetermined pressure with a width of 5 mm and a thickness of 170 nm,

It is preferable to perform patterning by wet etching using hydrochloric acid and nitric acid.

Here, the predetermined deposition rate is preferably 0.2? / S to 0.3? / S.

Here, the predetermined pressure is preferably 8 x 10 < -6 > Torr or more.

Wherein the hole injection layer

It is preferable that a monomolecular copper (CuPc) is deposited between the anode substrate and the hole transporting layer by thermal evaporation of a hetero-layer structure to a thickness of 10 nm or more and 30 nm or less.

The hole transport layer

It is preferable that TPD (N, N'-Bis (3-methylphenyl) -N, N'-dphenylbenzidine) is deposited to a thickness of 40 nm or less on the hole injection layer through thermal deposition.

In addition, the light-

It is preferable that Alq3 (Tris- (8-hydroxyquinoline) aluminum) is formed on the electron transport layer by thermal deposition to a thickness of 60 nm or less.

According to an aspect of the present invention,

Removing the foreign substances on the transparent substrate, depositing an organic material to a predetermined thickness using an organic material mask, patterning the organic material by wet etching to form a positive electrode substrate,

Forming a hole injection layer of CuPc on the anode substrate by thermal evaporation;

Forming a hole transport layer on the hole injection layer of CuPc by thermal evaporation;

Forming a light emitting layer on the hole transporting layer by thermal evaporation;

And forming a cathode substrate on the light emitting layer.

Here, the hole injection layer may include a hole injection layer,

It is preferable that the single-molecular-based CuPc is provided in a thickness of not less than 10 nm and not more than 30 nm by thermal vapor deposition of a hetero-layer structure.

As described above, according to the present invention, since the hole injection layer of CuPc, which is a monomolecular series, is formed by thermal vapor deposition of a hetero-layer structure using a glass crucible and a flying boat between an anode substrate and a hole transporting layer, Is superior in thermal oxidation and thermal stability compared with the organic materials of the conventional hole injection layer and has a similar ionization energy to the hole injection layer of the anode substrate and CuPc, The efficiency can be fundamentally improved.

According to the present invention, since the interface adhesion between the anode substrate and the hole transport layer is excellent by the hole injection layer of CuPc and the HOMO level of the hole injection layer of CuPc is slightly higher than the work function of the anode substrate, It is possible to inject holes into the hole, and the effect of improving the electrical stability is obtained.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate preferred embodiments of the invention and, together with the description of the invention given below, serve to further understand the technical idea of the invention. And should not be construed as limiting.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view showing a configuration of an organic light emitting device according to the present invention. FIG.
2 is a graph showing the molecular structure of a hole injection layer and a hole transport layer of CuPc in an organic light emitting device according to an embodiment of the present invention.
3 is a graph showing energy levels of respective layers of an organic light emitting diode of an organic light emitting diode according to an embodiment of the present invention.
4 is a graph showing the luminance versus voltage of each layer when the thickness of the hole injection layer of CuPc of the organic light emitting diode according to the embodiment of the present invention is varied.
FIG. 5 is a graph showing a logarithmic scale of luminance versus voltage when a thickness of a hole injection layer of CuPc of an organic light emitting diode according to an embodiment of the present invention is varied.
6 is a graph showing the current density versus voltage when the thickness of the hole injection layer of CuPc in the organic light emitting layer of the organic light emitting device according to the embodiment of the present invention is varied.
FIG. 7 is a graph showing electroluminescence (EL) of an organic light emitting device according to an embodiment of the present invention and a basic element in which CuPc is not deposited.
8 is a flowchart illustrating a manufacturing process of a light emitting layer of an organic light emitting diode according to another embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. In the following drawings, like reference numerals are used to denote like elements, and the same reference numerals are given to the same elements even if they are shown in different drawings, Detailed description of functions and configurations is omitted.

FIG. 1 is a view showing a configuration of an apparatus for manufacturing an organic light emitting diode according to an embodiment of the present invention.

1, an apparatus for manufacturing an organic light emitting diode according to an exemplary embodiment of the present invention includes an anode substrate 10, an organic light emitting layer 30, and a cathode substrate 50, 30 includes a hole injection layer 31, a hole transporting layer 33, and a light emitting layer 35.

Here, the anode substrate 10 is made of indium tin oxide (ITO), and the organic material is deposited to a thickness of 5 mm and a thickness of 170 nm at a predetermined deposition rate and a predetermined pressure, And performing patterning through wet etching using hydrochloric acid and nitric acid.

It is preferable that the predetermined deposition rate is 0.2 Å / s to 0.3 Å / s and the predetermined pressure is 8 × 10 -6 Torr or more.

On the other hand, the hole injection layer 32 is formed to a thickness of 10 nm or more and 30 nm or less through a monolayer system of copper phthalocyanine (CuPc) by heteroeposition deposition. At this time, a glass crucible and a flying boat are used for free deposition of the hetero-layer structure.

The hole transport layer 33 is formed to have a thickness of 40 nm or less through thermal deposition by TPD (N, N'-bis (3-methylphenyl) -N, N'-dphenylbenzidine) on the hole injection layer 32 .

A light emitting layer 35 is formed on the upper surface of the hole transport layer 33 by the combination of electrons and holes and the light emitting layer 35 is formed of Alq3 (Tris- (8-hydroxyquinoline) aluminum) Lt; RTI ID = 0.0 > thickness. ≪ / RTI >

FIG. 2 is a view showing the molecular structure of CuPc and the hole transport layer of the hole injection layer. FIG. 3 shows the energy level of each layer of the organic light emitting device. As shown in FIG. 3, 31, the lowering of the interface characteristics caused by the difference in the interface characteristics with respect to the junction portion between the anode substrate 10 and the organic light emitting layer 30 is alleviated as the surface energy level becomes higher.

4 is a graph showing the luminance versus voltage of each layer when the thickness of the hole injection layer of CuPc of the organic light emitting diode according to the embodiment of the present invention is varied. As shown in the figure, a turn-on voltage is generated in the vicinity of about 7 V and a maximum luminance is about 700 cd / m 2 in the vicinity of 11 V in the case of a base element in which a hole injection layer of CuPc is not deposited.

In addition, when the thickness of the hole injection layer of CuPc is 10 nm, 20 nm, and 30 nm, respectively, the luminance is improved at the same voltage of the basic element, whereas the thickness of the hole injection layer of CuPc is 40 nm and 50 nm, the luminance is smaller at the same voltage as that of the basic device.

In addition, near the about 10 V, the organic light emitting layer is able to withstand a short circuit, and thermal oxidation of the organic material starts due to the generated short circuit, so that the luminance of the organic light emitting layer gradually decreases.

For example, when the hole injection layer of CuPc has a thickness of 40 nm and 50 nm, more charge is injected at the same voltage as the basic device at the same voltage as the basic device, so that the current density is increased and accordingly more heat is generated. And less luminance is observed compared to the basic element due to the damage of this organic light emitting element.

Meanwhile, FIG. 5 is a graph showing a logarithmic scale of the luminance versus voltage when the thickness of the hole injection layer of CuPc of the organic light emitting device according to the embodiment of the present invention is changed, wherein the organic light emitting device having the hole injection layer of CuPc deposited thereon The turn-on voltage is generated faster than the basic element.

6 is a graph showing the current density versus voltage when the thickness of the CuPc hole injection layer of the light emitting layer of the organic light emitting diode according to the embodiment of the present invention is varied. As shown in the figure, it can be seen that the current density of the organic light emitting device having CuPc deposited therein is higher than that of the basic device at the same voltage.

FIG. 7 is a graph showing electroluminescence (EL) of an organic light emitting device according to an embodiment of the present invention and a basic element in which CuPc is not deposited.

Referring to FIG. 7, the organic light emitting device and the basic device according to the embodiment of the present invention similarly have a green wavelength at a wavelength of about 530 nm, and the light emitting layer 35 of Alq3 emits light.

 That is, when the thickness of the hole injection layer 31 of CuPc is 20 nm, the light emission luminance is maximized, while the light emission luminance is decreased at 30 nm or more. Therefore, when the hole injection layer of CuPc is used, the hole injection is smoothly performed. It can be seen that when the hole injection layer of CuPc is deposited to a thickness of 20 nm, the luminance emitted is maximized.

According to the embodiment of the present invention, a hole injection layer of CuPc, which is a monomolecular series, is provided through thermal deposition of a hetero-layer structure using a glass crucible and a flying boat between an anode substrate and a hole transport layer, The ionization energy of the positive hole injection layer of the positive electrode substrate is similar to that of the positive hole injection layer of the positive electrode substrate. Therefore, the efficiency of the emission luminance based on the hole injection layer of CuPc is essentially .

In addition, since the interface adhesion between the anode substrate and the hole transport layer is excellent by the hole injection layer of CuPc and the HOMO level of the hole injection layer of CuPc is slightly higher than the work function of the anode substrate, And the electrical stability is further improved.

A series of processes for providing a hole injection layer of CuPc, which is a monomolecular series, through thermal deposition using a glass crucible and a flying boat between an anode substrate and a hole transporting layer will be described with reference to FIG.

FIG. 8 is a flowchart illustrating an organic light emitting device manufacturing process according to another embodiment of the present invention. Referring to FIG. 8, a process of manufacturing the organic light emitting device shown in FIG. 1 will be described.

First, the anode substrate 10 is formed by removing foreign substances on a transparent substrate of an electrode material, depositing an organic material to a predetermined thickness using an organic material mask, and performing patterning by wet etching, 10 uses an indium tin oxide (ITO) material (step 101).

A hole injection layer 31 of the organic emission layer 30 is formed on the anode substrate 10. The hole injection layer 31 may be formed of a single crystal material such as copper phthalocyanine (CuPc) And a heterojunction structure using a flying boat.

At this time, the hole injection layer 31 of CuPc has a thickness of 10 nm or more and 30 nm or less (Step 103).

A hole transport layer 33 is formed on the CuPc hole injection layer by a thermal evaporation method. The hole transport layer 33 is formed on the hole injection layer 31 by using TPD (N, N'-Bis (3-methylphenyl) -N, N'-diphenylbenzidine) material is deposited to a thickness of 40 nm or less through thermal deposition (Step 105).

A light emitting layer 35 is formed on the upper surface of the hole transport layer 33 by the combination of electrons and holes and the light emitting layer 35 is formed of Alq3 (Tris- (8-hydroxyquinoline) aluminum) Lt; RTI ID = 0.0 > 107 < / RTI >

A series of processes of providing a cathode substrate of Al (cathode) on the light emitting layer 35 of Alq3 and a process of providing the cathode substrate are well known in the art, and a detailed description thereof will be omitted.

Accordingly, the hole injection layer of CuPc, which is a monomolecular series, is formed through thermal deposition of a hetero-layer structure using a glass crucible and a flying boat between the anode substrate and the hole transporting layer, Since the ionization energy of the positive hole injection layer of the positive electrode substrate is similar to that of the positive hole injection layer of the positive hole injection layer, the efficiency of the emission luminance is basically improved based on the hole injection layer of CuPc.

In addition, since the interface adhesion between the anode substrate and the hole transport layer is excellent by the hole injection layer of CuPc and the HOMO level of the hole injection layer of CuPc is slightly higher than the work function of the anode substrate, And the electrical stability is further improved.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

A hole injection layer of CuPc, which is a monomolecular series, is provided through thermal deposition of a hetero-layer structure using a glass crucible and a flying boat between an anode substrate and a hole transporting layer, so that a process of manufacturing a hole injection layer is easy, Layer and the hole injection layer of CuPc is similar to that of the hole injection layer of CuPc. Therefore, the efficiency of luminescence brightness is basically improved on the basis of the hole injection layer of CuPc, and the hole injection of CuPc Layer has an excellent interfacial adhesion between the anode substrate and the hole transporting layer and the HOMO level of the hole injection layer of CuPc is slightly higher than the work function of the anode substrate. Hence, holes can be injected at a voltage lower than the conventional voltage, In terms of accuracy and reliability of operation for the method and apparatus for manufacturing an organic light emitting diode which is further improved, And it is an industrially applicable invention since it is possible to carry out a commercially available or next generation display device to be applied on the market or to be operated in a realistic manner.

Claims (9)

An organic light emitting device for emitting light by coupling holes and electrons injected from a cathode substrate and an anode substrate with an organic light emitting material,
The organic light-
A hole transporting layer and a light emitting layer are sequentially formed on the anode substrate,
A hole injecting layer of a monomolecular type is further formed between the anode substrate and the hole transporting layer,
Wherein the hole injection layer
Wherein a single molecule of copper phthalocyanine (CuPc) is deposited between the anode substrate and the hole transport layer by thermal evaporation of a hetero-layer structure to a thickness of 10 nm or more and 30 nm or less.
The method according to claim 1,
An organic material was deposited on the transparent substrate of the electrode material at a predetermined deposition rate and a predetermined pressure with a width of 5 mm and a thickness of 170 nm,
And patterning is performed by wet etching using hydrochloric acid and nitric acid.
3. The apparatus of claim 2, wherein the predetermined deposition rate is 0.2 A / s to 0.3 A / s.
The organic light emitting diode manufacturing apparatus according to any one of claims 2 and 3, wherein the predetermined pressure is 8 x 10 < -6 > Torr or more.
delete The organic electroluminescence device according to claim 4, wherein the hole transport layer
Wherein TPD (N, N'-bis (3-methylphenyl) -N, N'-diphenylbenzidine) is deposited on the hole injection layer to a thickness of 40 nm or less by thermal evaporation.
7. The organic electroluminescent device according to claim 6,
Wherein Alq3 (Tris- (8-hydroxyquinoline) aluminum) is formed on the hole transport layer by thermal deposition to a thickness of 60 nm or less.
Removing the foreign substances on the transparent substrate, depositing an organic material to a predetermined thickness using an organic material mask, patterning the organic material by wet etching to form a positive electrode substrate,
Forming a hole injection layer of CuPc with a thickness of 10 nm or more and 30 nm or less by thermal deposition of mono-molecular-based CuPc on the anode substrate by thermal deposition;
Forming a hole transport layer on the hole injection layer of CuPc by thermal evaporation;
Forming a light emitting layer on the hole transporting layer by thermal evaporation;
And forming a cathode substrate on the light emitting layer. delete

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