KR101499027B1 - Method for manufacturing an organic light-emitting devicr with stacked auxiliary electrode and method of producing the same - Google Patents

Abstract

The present invention relates to an organic light emitting device in which a substrate, a first electrode, an organic material layer and a second electrode are sequentially stacked, wherein the organic light emitting device has a multi-layer structure for controlling the etching rate between the first electrode or the second electrode and the organic material layer The auxiliary electrode is laminated.
Thereby, the lifetime is prolonged and under-cut is not generated, and the non-uniformity of light emission is improved, which is applied to the organic light emitting device and its manufacturing method.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic light emitting diode (OLED), and more particularly to an organic light emitting diode (OLED)

The present invention relates to an organic light emitting device capable of preventing under-cut phenomenon by stacking an auxiliary electrode in which a metal oxide film layer is inserted in an organic light emitting device for fabricating a surface light source to improve unevenness of light emission by IR drop phenomenon, And a method of manufacturing the light emitting device.

The structure of conventional organic light emitting device is composed of glass substrate / anode transparent electrode / organic material / cathode metal / sealing layer, and light emitted from the organic material is emitted to the glass substrate to emit back light.

The driving principle of the organic light emitting device for illumination is based on the principle that light is generated by using current applied to the organic light emitting layer by generating an electric current using an external voltage. However, as the size of the organic light emitting device for illumination increases, the current injected from the anode and the cathode is not sufficiently supplied to the center portion due to the resistance component present in the organic light emitting device for illumination. This phenomenon is referred to as IR drop ).

FIG. 1 is an organic light emitting device for illumination in which a conventional IR drop phenomenon occurs.

As shown in FIG. 1, as the conventional organic light emitting device for illumination increases in size, the uniformity of light emission is lowered in the center region of the organic light emitting device. To solve this problem, Electrode was inserted so that a uniform current was applied to the center portion of the organic light emitting device for large area illumination.

Conventionally, as disclosed in a prior art publication No. 10-2013-0028305, auxiliary electrodes are formed in a rectangular shape using any one of Cr, Mo / Al / Mo, and Cu as metal auxiliary electrodes, drop phenomenon, but did not completely solve the above problem.

In general, when a metal auxiliary electrode is applied to an organic light emitting device for illumination, a metal auxiliary electrode is deposited, and a pattern is formed using a photo lithography technique and a wet etching technique, thereby avoiding direct contact with a cathode metal electrode. At this time, the metal-assisted electrode deposition technique uses a sputtering process showing advantages in mass production, and the wet etching process uses a mixture of various kinds of acidic solutions suitable for each auxiliary electrode material.

As the auxiliary electrode, 300 nm thick Cr was initially used, but in this case, the sheet resistance of Cr was 1.2 ohm / cm ^2, which is a considerably high value in metal. When Cr having a high sheet resistance is used, heat is generated to shorten the lifetime of the large-area organic light emitting device for illumination, and an IR drop phenomenon occurs due to a relatively large resistance of the input current. In the device, light emission unevenness is caused.

FIG. 2 is a cross-sectional view of an auxiliary electrode manufactured in order to solve the problem of Cr used as a conventional auxiliary electrode.

As shown in FIG. 2, the substitute auxiliary electrode has a three-layer structure of Mo / Al / Mo.

Here, Mo in the sandwich structure is an oxidation preventing layer for preventing the oxidation of the auxiliary electrode of Al, and Al serving as the middle metal layer serves to prevent the IR drop phenomenon by supplying a uniform current to the entire region of the organic light emitting device .

However, when the three-layer structure of Mo / Al / Mo is applied as shown in FIG. 3, the etching rates of Mo and Al are different from each other in pattern formation using wet etching, and an under-cut problem occurs .

Such under-cut is a phenomenon generally observed in a wet etching process, in which the pattern protrudes to the outside, causing a current crowding or current crowding to occur at the protruding portion. Particularly, such an under-cut portion exists as a remnant of the metal, and acts as a particle source that plays a critical role in the lifetime of the large-area organic light emitting device for illumination. In addition, The occurrence of hot spot phenomenon occurs, so that the lifetime of the organic light emitting device is shortened because the luminance is increased only in a specific region.

The metal particles in the under-cut portion cause direct contact between the anode transparent electrode and the cathode metal electrode during driving of the organic light emitting device for large-area illumination, causing a short circuit phenomenon, The lifetime of the device is shortened.

In order to improve the luminescence non-uniformity due to the IR drop phenomenon occurring in the organic light emitting device for large-area lighting, a considerable effect has been obtained by inserting the metal auxiliary electrode. In order to stably drive the organic light emitting device for large- And it is necessary to apply a new metal auxiliary electrode material or a new structure that does not have under-cut problems during wet etching.

An object of the present invention is to provide an organic light emitting device in which a metal auxiliary electrode free from under-cut is inserted and a method of manufacturing the same.

Another object of the present invention is to provide an organic light emitting device and a method of manufacturing the same, wherein the unevenness of luminescence is improved by controlling the undercut generated when wet etching of the metal auxiliary electrode of a multilayer structure is controlled.

Still another object of the present invention is to provide an organic light emitting device having an extended lifetime by controlling particles that can occur in a metal-assisted electrode of an inserted multilayer structure, and a method of manufacturing the same.

The objects of the present invention are not limited to the above-mentioned objects, and other objects not mentioned can be clearly understood by those skilled in the art from the following description.

According to an aspect of the present invention, there is provided an organic light emitting diode comprising a substrate, a first electrode, an organic material layer, and a second electrode sequentially stacked on the substrate, wherein the first electrode or the second electrode, And an auxiliary electrode having a multi-layered structure for controlling the rate of light emission are stacked.

In a preferred embodiment, the auxiliary electrode includes a plurality of metal layers formed between at least a pair of oxidation preventing layers, and a metal oxide layer formed between adjacent metal layers of the metal layers.

In a preferred embodiment, the metal layer and the metal oxide layer are alternately stacked.

In a preferred embodiment, the metal layer is laminated with any one of Al, Ag, Cu, Au, Nb, W, and Cr, or at least two alloy thin films thereof.

In a preferred embodiment, the metal oxide layer is any one of Al ₂ O _3, Cr ₂ O ₃ , and NiO.

In a preferred embodiment, the auxiliary electrode is laminated between any one of the first electrode and the second electrode, which is an anode, and the organic material layer.

According to another aspect of the present invention, there is provided a method of manufacturing an organic light emitting diode in which a substrate, a first electrode, an organic material layer, and a second electrode are sequentially stacked, the method comprising: providing a multilayered structure having an etching rate controllable between the first electrode and the second electrode, A method of manufacturing an organic light emitting device in which electrodes are stacked.

In a preferred embodiment, the auxiliary electrode includes at least a plurality of metal layers formed between at least one pair of oxidation preventing layers, and a metal oxide layer formed between both metal layers adjacent to each other of the metal layers.

In a preferred embodiment, the metal layer and the metal oxide layer are alternately stacked.

In a preferred embodiment, the metal layer is laminated with any one of Al, Ag, Cu, Au, Nb, W, and Cr, or at least two alloy thin films thereof.

In a preferred embodiment, the metal oxide layer is any one of Al ₂ O _3, Cr ₂ O ₃ , and NiO.

In a preferred embodiment, the auxiliary electrode is laminated between any one of the first electrode and the second electrode, which is an anode, and the organic material layer.

According to another aspect of the present invention, there is provided an organic light emitting device including a substrate, a first electrode, an organic material layer, and a second electrode, wherein a multi-layered auxiliary electrode for controlling an etching rate is laminated between the first electrode or the second electrode and the organic material layer Wherein the auxiliary electrode comprises: a pair of oxidation preventing layers; A plurality of metal layers formed between the pair of oxidation preventing layers; And a metal oxide layer formed between both metal layers adjacent to each other in the metal layer, wherein the metal layer and the metal oxide layer are alternately laminated, and the metal layer is formed of Al, Ag, Cu, Au, Nb, W, Cr Wherein the metal oxide layer is one of Al ₂ O _3, Cr ₂ O ₃ , and NiO.
In the present invention, the auxiliary electrode may have a laminated structure in which layers are formed in the order of an oxidation preventing layer, a metal layer, a metal oxide layer, a metal layer, and an oxidation preventing layer from one side; A laminated structure in which layers are formed in order from an antioxidant layer, a metal layer, a metal oxide layer, a metal layer, a metal oxide layer, a metal layer, and an antioxidant layer; And a laminated structure in which layers are formed in the order of an oxidation preventing layer, a metal layer, a metal oxide layer, a metal layer, a metal oxide layer, a metal layer, a metal oxide layer, a metal layer and an antioxidant layer from one side Emitting layer.
In the present invention, the auxiliary electrode is laminated between any one of the first electrode and the second electrode, which is an anode, and the organic material layer.
In the present invention, an organic light emitting device is manufactured in which a substrate, a first electrode, an organic material layer and a second electrode are stacked, and a multi-layered auxiliary electrode for controlling the etching rate between the first electrode or the second electrode and the organic material layer is stacked The auxiliary electrode includes at least a plurality of metal layers formed between at least a pair of oxidation preventing layers and a metal oxide layer formed between mutually adjacent metal layers of the metal layers, Wherein the metal layer is laminated with at least one of Al, Ag, Cu, Au, Nb, W, and Cr, or at least two of them, and the metal oxide layer is formed of Al ₂ O _3, Cr ₂ O ₃ , and NiO. The present invention also provides a method of manufacturing an organic light emitting diode.
In the present invention, the auxiliary electrode may have a laminated structure in which layers are formed in the order of an oxidation preventing layer, a metal layer, a metal oxide layer, a metal layer, and an oxidation preventing layer from one side; A laminated structure in which layers are formed in order from an antioxidant layer, a metal layer, a metal oxide layer, a metal layer, a metal oxide layer, a metal layer, and an antioxidant layer; And a laminated structure in which layers are formed in the order of an oxidation preventing layer, a metal layer, a metal oxide layer, a metal layer, a metal oxide layer, a metal layer, a metal oxide layer, a metal layer and an antioxidant layer from one side Emitting layer.
In the present invention, the auxiliary electrode is laminated between any one of the first electrode and the second electrode, which is an anode, and the organic material layer.

The present invention has the following effects.

First, under-cut is not generated in the organic light emitting device and the manufacturing method thereof according to the present invention.

Further, the organic light emitting device and the method of manufacturing the same of the present invention are improved in luminescence unevenness.

Further, the life span of the organic light emitting device and the manufacturing method thereof of the present invention is prolonged.

1 is an IR drop phenomenon image generated in a conventional organic light emitting device.
2 is a cross-sectional view of a conventional auxiliary electrode.
3 is a photograph showing an under-cut phenomenon occurring in a conventional auxiliary electrode.
4 to 6 are perspective views showing a cross section of the auxiliary electrode according to the embodiment of the present invention.
7 is an auxiliary electrode image produced through the deposition step according to an embodiment of the present invention.
8 is a photograph of light emission of an organic light emitting device in which an auxiliary electrode according to an embodiment of the present invention and a conventional auxiliary electrode are stacked.

The structure of the organic light emitting diode according to one embodiment of the present invention is described as follows.

The organic light emitting device according to an embodiment of the present invention includes a substrate, a first electrode, an organic material layer, and a second electrode, wherein an auxiliary electrode for controlling an etching rate between the first electrode or the second electrode and the organic material layer .

Here, the substrate is located at the bottom of the organic light emitting element, and the type of the substrate is not limited to any one, and it is preferable to use any one of a glass substrate, a flexible substrate capable of bending, and a transparent substrate made of a semiconductor substrate.

Next, the first electrode and the second electrode function as an anode metal layer or a cathode metal layer in the organic light emitting device. When any one of the first electrode and the second electrode is deposited as a cathode metal layer, Deposition is achieved.

Here, any one of the first electrode and the second electrode, which is an anode, is required to be transparent because it needs to project light emitted by the organic material layer, and should be colorless and high in electrical conductivity. Among them, As shown in Fig.

The organic material layer is a constituent element which is deposited on the first electrode to emit light, and the material of the organic material layer and the deposition method are not limited to any one.

The second electrode is a component deposited on the organic layer.

When the first electrode is deposited as an anode, the second electrode is deposited as a cathode metal layer, and when the first electrode is deposited as a cathode metal layer, the second electrode is deposited as a cathode metal layer.

Next, the auxiliary electrode 50 is laminated between any one of the first electrode and the second electrode, which is an anode, and the organic layer in order to improve luminescent unevenness due to an IR drop phenomenon occurring in the organic light emitting device.

The auxiliary electrode 50 includes a pair of oxidation prevention layers 51 that prevent oxidation of the metal layer 52, a plurality of metal layers 52 formed between the oxidation prevention layers 51 to prevent IR drop phenomenon, And a metal oxide layer 53 for controlling the etching rate of the metal layer 52.

The auxiliary electrode 50 is formed by stacking a plurality of metal layers 52 between at least one pair of oxidation prevention layers 51 and between the metal layers 52 adjacent to each other in the metal layer 52, The metal layer 52 and the metal oxide layer 53 are stacked alternately.

The antioxidant layer 51 is formed on both ends of the auxiliary electrode 50 and has at least one pair of the antioxidant layers 51. The metal layer 52 and the metal oxide layer 53 are formed between the antioxidant layers 51. [ Here, the oxidation preventing layer 51 prevents the oxidation of the metal layer 52, and the kind thereof is not limited to any one, but it is preferable to use Mo.

Next, the metal layer 52 is formed between the pair of oxidation preventing layers 51 to prevent the IR drop phenomenon, and a plurality of metal layers 52 are formed.

The metal layer 52 may be formed of any one of Al, Ag, Cu, Au, Nb, W and Cr, or at least two alloy thin films thereof. .

The metal oxide layer 53 is a constituent element formed between the mutually adjacent metal layers 52. The metal layer 52 makes the different etching rates of the metal layer 52 uniform so as to prevent the occurrence of undercuts, Value is maintained, the heat generation of the organic light emitting diode 1 is reduced, thereby extending the lifetime and improving the light emission characteristic.

Therefore, the metal oxide layer 53 is formed of any one of Al ₂ O _3, Cr ₂ O ₃ , and NiO. The etch rate of the metal layer 52 is uniform, so that under- It may be used as any one, but it is preferable to laminate it with Al ₂ O ₃ .

The auxiliary electrode 50 including the oxidation preventing layer 51, the metal layer 52 and the metal oxide layer 53 may be formed as an anode of the first and second electrodes of the organic light emitting diode. And is laminated between one electrode and the organic material layer.

This is because the auxiliary electrode 50 needs to be supplied with a constant current from the edge to the center of the organic light emitting diode and the mobility of the hole is about three times lower than the mobility of electrons. 50 are preferably stacked between an electrode provided as an anode and the organic material layer.

4 to 6 are cross-sectional views of the auxiliary electrode 50 according to the embodiment of the present invention.

4 through 6, the auxiliary electrode 50 includes a plurality of metal layers 52 stacked between a pair of oxidation preventing layers 51, and a metal layer 52 adjacent to each other of the metal layers 52 The metal oxide layer 53 is laminated between the metal layers 52 to control the etching rate of the metal layer 52 to prevent the occurrence of undercuts

As shown in FIG. 4, the auxiliary electrode 50 according to an embodiment of the present invention includes:

Antioxidant layer / metal layer / metal oxide layer / metal layer / antioxidant layer.

As shown in FIG. 5, the auxiliary electrode 50 according to another embodiment of the present invention may be stacked with the oxidation prevention layer / metal layer / metal oxide layer / metal layer / metal oxide layer / metal layer / oxidation prevention layer.

6, the auxiliary electrode 50 according to another embodiment of the present invention may include an oxidation preventing layer / a metal layer / a metal oxide layer / a metal layer / a metal oxide layer / a metal layer / a metal oxide layer / a metal layer / . ≪ / RTI >

A method of manufacturing the organic light emitting device in which the auxiliary electrodes 50 according to the above embodiments are stacked is as follows.

The organic light emitting device comprising: a substrate; A first electrode deposition step of depositing a first electrode layer on the substrate; Depositing an organic material on the first electrode layer; And a second electrode deposition step of depositing a second electrode on the organic material layer.

Here, the auxiliary electrode deposition step for depositing the auxiliary electrode may include depositing an auxiliary electrode between the first electrode layer and the second electrode layer, and depositing the auxiliary electrode between the first electrode layer and the second electrode layer, .

The auxiliary electrode 50 is deposited by any one of atomic layer deposition, chemical vapor deposition, thermal deposition, and sputter deposition, and a pattern is formed by photo-lithography. However, the deposition method is not limited to any one.

The auxiliary electrode 50 is formed by alternately laminating the metal layer 52 and the metal oxide layer 53 on the auxiliary electrode 50. The auxiliary electrode 50 is formed by alternately laminating the metal layer 52 and the metal oxide layer 53, By stacking the organic light emitting device on the organic light emitting device, the etching rate of the metal layer 52 is controlled to prevent under-cut, thereby improving the light emission unevenness of the organic light emitting device.

Example

As shown in FIG. 5, an auxiliary electrode having a structure of an antioxidant layer / metal layer / metal oxide layer / metal layer / metal oxide layer / metal layer / antioxidant layer was prepared according to the process steps and process conditions shown in Table 1.

Al / Al ₂ O ₃ / Al / Al ₂ O ₃ / Al ₂ O ₃ / Al ₂ O ₃ metal layer, and the auxiliary electrode is deposited by sputtering deposition to form Mo / Al / Al ₂ O ₃ / Al / Al ₂ An auxiliary electrode having an O ₃ / Al / Mo structure was formed. The deposition process of the auxiliary electrode is shown in the following table.

division Mo Al Al ₂ O ₃ Al Al ₂ O ₃ Al Mo Heating temp.
() 27 27 27 27 27 27 27 Working pressure
(mTorr) 2 2 10 2 10 2 10 Ar flow rate
(sccm) 100 100 50 100 50 100 100 O ₂ flow rate
(sccm) - - 5 - 5 - - power
(DC Watt) 1000 3000 300 3000 300 3000 1000 공정 시간
(sec) 56 108 20 108 20 108 80 Base pressure
(Torr) = 5 × 10 ^-7 = 5 × 10 ^-7 = 5 × 10 ^-7 = 5 × 10 ^-7 = 5 × 10 ^-7 = 5 × 10 ^-7 = 5 × 10 ^-7 Sheet resistance
(O /) 0.12 Thickness
(nm) 350 1000 30 1000 30 1000 500

Comparative Example

A conventional auxiliary electrode having the structure of the oxidation preventing layer / metal layer / oxidation preventing layer shown in FIG. 2 was produced according to the process steps and the process conditions shown in Table 2.

The anti-oxidation layer was formed of Mo, the metal layer was formed of Al, and an auxiliary electrode having a Mo / Al / Mo structure was formed by sputtering deposition.

Conventional auxiliary electrode deposition conditions are shown in the following table

division Mo Al Mo Heating temp.
() 27 27 27 Working pressure
(mTorr) 2 2 10 Ar flow rate
(sccm) 100 100 100 O ₂ flow rate
(sccm) - - - power
(DC Watt) 1000 3000 1000 공정 시간
(sec) 56 108 80 Base pressure
(Torr) = 5 × 10 ^-7 = 5 × 10 ^-7 = 5 × 10 ^-7 Sheet resistance
(O /) 0.12 Thickness
(nm) 350 1000 500

Experimental Example 1

A pattern was formed using the conventional photo-lithography process of the auxiliary electrode Mo / Al / Al ₂ O ₃ / Al / Al ₂ O ₃ / Al / Mo obtained in the example and then etched using a wet etching process. The results measured through a microscope are shown in Figs. 7 (a) and 7 (b).

7 (a) and 7 (b), the auxiliary electrode manufactured through the deposition step of the present invention does not cause an under-cut phenomenon occurring in the conventional auxiliary electrode shown in FIG. 2, As shown in Fig.

Experimental Example 2

The organic light emitting device obtained by depositing the auxiliary electrode Mo / Al / Al ₂ O ₃ / Al / Al ₂ O ₃ / Al / Mo and the conventional auxiliary electrode Mo / Al / Mo, The auxiliary auxiliary electrode Mo / Al / Mo is shown in FIG. 8 (a), and the auxiliary electrode Mo / Al / Al ₂ O ₃ / Al / Al ₂ O ₃ / Al / Mo 8 (b).

The organic light emitting device having the auxiliary electrode Mo / Al / Mo deposited thereon as shown in FIG. 8 (a) has no problem in initial light emission, but particles are generated over time, and current crowding phenomenon It can be seen that the In addition, it was confirmed that a hot spot where an emission luminance increases in a local region is generated at a portion where a particle is generated, and thus organic matter can not emit light in some regions.

The organic light emitting device having the auxiliary electrode Mo / Al / Al ₂ O ₃ / Al / Al ₂ O ₃ / Al / Mo deposited thereon showed no change in luminescence phenomenon even after 50 hours, The deposition of Al ₂ O ₃ controlled the generation of undercuts, which confirmed that the current density was not increased in the localized region.

Therefore, under-cut generation of the organic light emitting device can be controlled by depositing the auxiliary electrode Mo / Al / Al ₂ O ₃ / Al / Al ₂ O ₃ / Al / Mo according to the embodiment, It was confirmed that the uniformity can be improved.

50: auxiliary electrode
51: Oxidation preventing layer
52: metal layer
53: metal oxide layer

Claims (12)

A substrate, a first electrode, an organic material layer, and a second electrode,
And an auxiliary electrode having a multilayer structure for controlling an etching rate between the first electrode or the second electrode and the organic material layer,
The auxiliary electrode
A pair of antioxidant layers;
A plurality of metal layers formed between the pair of oxidation preventing layers; And
And a metal oxide layer formed between both metal layers adjacent to each other in the metal layer,
Wherein the metal layer and the metal oxide layer are alternately stacked,
Wherein the metal layer is formed of one of Al, Ag, Cu, Au, Nb, W and Cr, or at least two alloy thin films thereof,
Wherein the metal oxide layer is any one of Al ₂ O _3, Cr ₂ O ₃ , and NiO.
The method according to claim 1,
The auxiliary electrode
A laminated structure in which layers are formed in the order of an oxidation preventing layer, a metal layer, a metal oxide layer, a metal layer, and an oxidation preventing layer from one side;
A laminated structure in which layers are formed in order from an antioxidant layer, a metal layer, a metal oxide layer, a metal layer, a metal oxide layer, a metal layer, and an antioxidant layer; And
A laminated structure in which layers are formed from an antioxidant layer, a metal layer, a metal oxide layer, a metal layer, a metal oxide layer, a metal layer, a metal oxide layer, a metal layer, and an antioxidant layer in this order;
The organic light emitting device comprising:
delete delete delete The method according to claim 1,
Wherein the auxiliary electrode is laminated between any one of the first electrode and the second electrode, and the organic material layer.
A substrate, a first electrode, an organic material layer, and a second electrode are stacked,
A method of manufacturing an organic light emitting diode in which an auxiliary electrode having a multilayer structure for controlling an etching rate is laminated between the first electrode or the second electrode and the organic material layer,
Wherein the auxiliary electrode includes at least a plurality of metal layers formed between at least one pair of oxidation preventing layers and a metal oxide layer formed between both metal layers adjacent to each other of the metal layers,
Wherein the metal layer and the metal oxide layer are alternately stacked,
Wherein the metal layer is formed of one of Al, Ag, Cu, Au, Nb, W and Cr, or at least two alloy thin films thereof,
Wherein the metal oxide layer is any one of Al ₂ O _3, Cr ₂ O ₃ , and NiO.
8. The method of claim 7,
The auxiliary electrode
A laminated structure in which layers are formed in the order of an oxidation preventing layer, a metal layer, a metal oxide layer, a metal layer, and an oxidation preventing layer from one side;
A laminated structure in which layers are formed in order from an antioxidant layer, a metal layer, a metal oxide layer, a metal layer, a metal oxide layer, a metal layer, and an antioxidant layer; And
A laminated structure in which layers are formed from an antioxidant layer, a metal layer, a metal oxide layer, a metal layer, a metal oxide layer, a metal layer, a metal oxide layer, a metal layer, and an antioxidant layer in this order;
Wherein the organic light emitting layer is formed of a single layer structure.
delete delete delete 8. The method of claim 7,
Wherein the auxiliary electrode is laminated between any one of the first electrode and the second electrode as an anode and the organic material layer.

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