KR20120072891A - Method manufacturing of organic light emitting diode - Google Patents

Abstract

PURPOSE: A method for manufacturing an organic light emitting device is provided to easily form a hole transport layer, a light emitting layer, and an electron transport layer through one scanning process by separately arranging electron transport materials and hole transport materials in a source moving in one direction. CONSTITUTION: A first electrode(120) is located on a substrate(110). A hole injection layer(131) is located on the first electrode. A hole transport layer(132) is located on the hole injection layer. A light emitting layer(140) is located on the hole transport layer. An electron transport layer(151) and an electron injection layer(152) are located on the light emitting layer. A second electrode(160) is located on the electron injection layer.

Description

Manufacturing method of organic electroluminescent device {METHOD MANUFACTURING OF ORGANIC LIGHT EMITTING DIODE}

The present invention relates to an organic light emitting display device, and more particularly, to a method of manufacturing an organic light emitting display device.

2. Description of the Related Art In recent years, the importance of flat panel displays (FPDs) has been increasing with the development of multimedia. In response to this, a variety of liquid crystal displays (LCDs), plasma display panels (PDPs), field emission displays (FEDs), organic light emitting devices (Organic Light Emitting Devices), etc. Flat panel displays have been put into practical use.

In particular, the organic light emitting device has a high response time with a response speed of 1 ms or less, low power consumption, and self-luminous light. In addition, there is no problem in viewing angle, which is advantageous as a moving image display medium regardless of the size of the device. In addition, low-temperature manufacturing is possible, and the manufacturing process is simple based on the existing semiconductor process technology has attracted attention as a next-generation flat panel display device in the future.

The organic light emitting device includes a light emitting layer between the anode and the cathode, and holes supplied from the anode and electrons received from the cathode combine in the light emitting layer to form an exciton, which is a hole-electron pair, and then the excitons return to the ground state. The energy is emitted by the generated energy.

However, the organic light emitting device as described above has a great influence on the life and efficiency of the device depending on the material and the laminated structure used. Therefore, research for developing an organic light emitting display device having a superior lifetime and efficiency is ongoing.

The present invention provides a method of manufacturing an organic light emitting display device having excellent lifespan and luminous efficiency.

In order to achieve the above object, a method of manufacturing an organic light emitting display device according to an embodiment of the present invention comprises the steps of forming a first electrode on a substrate, the hole transport material and electron transport on the substrate on which the first electrode is formed Preparing a source in which materials are arranged in order, scanning once while heating the source in the direction in which the hole transport material is disposed, a hole transport layer on the first electrode, a mixed layer of the hole transport material and the electron transport material And sequentially forming a phosphorescent emission layer and an electron transporting layer at the same time, and forming a second electrode on the emission layer.

The source may further include a green phosphorescent dopant material positioned between the hole transport material and the electron transport material, and may deposit the dopant material simultaneously with the deposition of the hole transport material and the electron transport material.

Forming the hole transport layer, the light emitting layer and the electron transport layer which is a mixed layer of the hole transport material and the electron transport material, the hole transport material of the source is first deposited on the substrate, to form a hole transport layer, the hole transport layer While forming, the deposition of the electron transport material of the source is started to form the light emitting layer by the co-deposition of the hole transport material and the electron transport material and the light emitting layer is formed, only the electron transport material is deposited electrons Forming a transport layer may be included.

Before forming the hole transport layer, the method may further include forming a hole injection layer on the first electrode.

Before forming the second electrode, the method may further include forming an electron injection layer on the electron transport layer.

In the light emitting layer, a mixing ratio of the hole transport material and the electron transport material may be 1: 1.

Scanning of the source may begin at one outer side of the substrate and end at the other outer side of the substrate.

An organic light emitting display device according to an embodiment of the present invention has an advantage of greatly improving light emission efficiency and lifetime by forming a light emitting layer having a mixing ratio of a hole transport material and an electron transport material in a 1: 1 ratio. In addition, through the process of scanning the source, there is an advantage that can easily form a hole transport layer, a light emitting layer and an electron transport layer.

1 is a view showing an organic light emitting display device according to an embodiment of the present invention.
2 is a view showing a deposition apparatus for manufacturing an organic light emitting display device according to an embodiment of the present invention.
3 is a plan view showing a source according to an embodiment of the present invention.
4A to 4C are diagrams illustrating processes for manufacturing an organic light emitting display device according to one embodiment of the present invention.
5 is a graph showing the life of the organic light emitting display device manufactured according to Example 1 and Comparative Example of the present invention.
Figure 6 is a graph showing the measurement of the life of the organic light emitting display device manufactured according to Examples 1, 2 and 3 of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a view showing an organic light emitting display device according to an embodiment of the present invention.

Referring to FIG. 1, an organic light emitting display device 100 according to an embodiment of the present invention may include a substrate 110, a first electrode 120 and a first electrode 120 positioned on the substrate 110. On the hole injection layer 131 positioned on the hole, the hole transport layer 132 located on the hole injection layer 131, the light emitting layer 140 located on the hole transport layer 132, on the light emitting layer 140 The electron transport layer 151 may be positioned, an electron injection layer 152 positioned on the electron transport layer 151, and a second electrode 160 located on the electron injection layer 152.

The substrate 110 may be made of glass, plastic, or metal, and may further include a thin film transistor including a semiconductor layer, a gate electrode, a source electrode, and a drain electrode.

The first electrode 120 may be a transparent electrode or a reflective electrode. When the first electrode 120 is a transparent electrode, the first electrode 120 may be any one of indium tin oxide (ITO), indium zinc oxide (IZO), or zinc oxide (ZnO).

In addition, when the first electrode 120 is a reflective electrode, the first electrode 120 is formed of any one of aluminum (Al), silver (Ag), or nickel (Ni) under a layer made of any one of ITO, IZO, or ZnO. The reflective layer may further include a reflective layer, and in addition, the reflective layer may be included between two layers made of any one of ITO, IZO, or ZnO.

The first electrode 120 may be formed using a sputtering method, an evaporation method, a vapor phase deposition method, or an electron beam deposition method.

The hole injection layer 131 and the hole transport layer 132 are positioned on the first electrode 120. The hole injection layer 131 may play a role of smoothly injecting holes from the first electrode 120 to the emission layer 140, and may include cupper phthalocyanine (CuPc) and poly (3,4) -ethylenedioxythiophene (PEDOT). , PANI (polyaniline) and NPD (N, N-dinaphthyl-N, N'-diphenyl benzidine) may be made of any one or more selected from the group consisting of, but is not limited thereto.

The hole injection layer 131 may be formed using an evaporation method or a spin coating method.

The hole transport layer 132 serves to facilitate the transport of holes, NPD (N, N-dinaphthyl-N, N'-diphenyl benzidine), TPD (N, N'-bis- (3-methylphenyl)- N, N'-bis- (phenyl) -benzidine), s-TAD and MTDATA (4,4 ', 4 "-Tris (N-3-methylphenyl-N-phenyl-amino) -triphenylamine) It may be made of any one or more, but is not limited thereto.

The hole transport layer 132 may be formed using an evaporation method or a spin coating method.

The emission layer 140 is positioned on the hole transport layer 132. The emission layer 140 may be a mixed layer of a hole transport material and an electron transport material. Here, the hole transport material is made of hole transport materials to facilitate the transport of holes, for example, may be made of the same material as the hole transport layer described above. In addition, the electron transport material is made of an electron transport material to facilitate the transport of electrons, for example, in the group consisting of Alq3 (tris (8-hydroxyquinolino) aluminum), PBD, TAZ, spiro-PBD, BAlq and SAlq It may be made of one or more selected, but is not limited thereto.

The light emitting layer 140 is a mixed layer of a hole transport material and an electron transport material, the mixing ratio of the hole transport material and the electron transport material is 1: 1. If the mixing ratio of the hole transporting material and the electron transporting material is increased to one of the light emitting layers 140, the charges are lost as heat without emitting light at the interface between the hole transporting layer and the light emitting layer or the electron transporting layer and the light emitting layer, thereby deteriorating the device. There is a problem that results. Therefore, in the present invention, the mixing ratio of the hole transporting material and the electron transporting material in the light emitting layer 140 is 1: 1.

The hole transport material and the electron transport material mixed in the light emitting layer 140 each act as a host material of the light emitting layer 140. In addition, the emission layer 140 includes a green phosphorescent dopant. The green phosphorescent dopant may include, for example, Ir (ppy) 2 (acac) or Ir (ppy) 3 (fac tris (2-phenylpyridine) iridium).

The electron transport layer 151 is positioned on the light emitting layer 140. The electron transport layer 151 may be made of the above-described electron transport material.

The electron injection layer 152 is positioned on the electron transport layer 151. The electron injection layer 152 serves to facilitate the injection of electrons, and may be used as Alq3 (tris (8-hydroxyquinolino) aluminum), PBD, TAZ, spiro-PBD, BAlq or SAlq, but is not limited thereto. In addition, the electron injection layer 152 may be made of an inorganic material, and the inorganic material may be a metal compound. For example, the electron injection layer 152 may include an alkali metal or an alkaline earth metal, and the metal compound including the alkali metal or the alkaline earth metal may be LiQ, LiF, NaF, KF, RbF, CsF, FrF, BeF ₂ , _{MgF 2, CaF 2, SrF 2} , BaF 2 and RaF ₂ be at least one selected from the group consisting of, but not limited to this. The electron injection layer 152 may be formed using an evaporation method or a spin coating method, and the thickness of the electron injection layer 152 may be 1 to 50 nm.

The second electrode 160 is positioned on the electron injection layer 152. The second electrode 160 may be made of magnesium (Mg), calcium (Ca), aluminum (Al), silver (Ag), or an alloy thereof having a low work function. Here, the second pole 160 may be formed to a thickness thin enough to transmit light when the organic light emitting device is a front or double-sided light emitting structure, when the organic light emitting device is a rear light emitting structure, the light It can be formed thick enough to reflect. As described above, the organic light emitting display device 100 according to the exemplary embodiment of the present invention may be configured.

Hereinafter, a method of manufacturing the organic light emitting display device according to the embodiment of the present invention described above is as follows.

2 is a view showing a deposition apparatus for manufacturing an organic light emitting display device according to an embodiment of the present invention, Figure 3 is a plan view showing a source according to an embodiment of the present invention.

2 and 3, in the deposition apparatus 300, a substrate 110 is fixed to a substrate plate 320 in a vacuum chamber 310, and a source 330 containing a deposition material under the substrate 110. ) Will be located. In this case, the source 330 may reciprocate in a predetermined direction.

On one surface of the source 330, the hole transport material 340 is arranged on one side, and the electron transport material 360 is arranged on the other side. The green phosphorescent dopant 350 is arranged between the electron transport material 340 and the hole transport material 360.

The manufacturing method of the organic electroluminescent device of the present invention using the deposition apparatus 300 configured as described above will be described as follows.

4A to 4C are diagrams illustrating processes for manufacturing an organic light emitting display device according to one embodiment of the present invention.

Referring to FIG. 4A, after forming the first electrode and the hole injection layer on the substrate 110, the substrate 110 is mounted on the substrate plate 320 of the vacuum chamber.

The hole transport material 340, the electron transport material 360, and the green phosphorescent dopant (not shown) are arranged in the source 330, and then the source 330 is heated to arrange the hole transport material 340. Scan with

In this case, since the hole transport material 340 and the electron transport material 360 are arranged to be spaced apart from each other in the source 330, as shown in the drawing, only the hole transport material 340 is evaporated (A1) and the hole transport is performed. The material 340 and the electron transport material 360 are divided into a region A2 at which the evaporation is simultaneously evaporated, and only the electron transport material 360 is evaporated. In addition, the green phosphorescent dopant (not shown) is simultaneously evaporated in all regions.

In addition, the scanning of the source 330 starts at one side of the substrate 110. That is, the region A1 in which only the hole transport material 340 is evaporated is located at one outer side of the substrate 110 and then vaporized and deposited on the substrate 110 according to the scan of the source 330.

Subsequently, referring to FIG. 4B, when the first scan of the source 330 is performed, since the region A1 deposited from the hole transport material 340 is first deposited on the substrate 110, only the hole transport material 340 may be used. The hole transport layer 132 is formed by being deposited on 110.

Then, a region A2 in which the hole transport material 340 and the electron transport material 360 are simultaneously evaporated is subsequently deposited on the substrate 110, and the hole transport material 340 and the electron transport material 360 are co-deposited. The light emitting layer 140 is formed.

A region A3 in which the electron transport material 360 is evaporated is subsequently deposited on the substrate 110 to form an electron transport layer 151. Therefore, as shown in FIG. 4C, the hole transport layer 132, the light emitting layer 140, and the electron transport layer 151 are sequentially formed on the substrate 110. In this case, the scan of the source 330 is terminated at the other outer periphery of the substrate 110. That is, as shown in the figure, the scan is terminated after the region A3 in which only the electron transport material 360 is evaporated completely escapes to the other outer side of the substrate 110.

Next, an electron transport layer and a second electrode are formed on the substrate 110 on which the electron transport layer 151 is formed, thereby manufacturing an organic light emitting display device according to an exemplary embodiment.

As described above, in the method of manufacturing an organic light emitting display device according to an embodiment of the present invention, by disposing an electron transport material and a hole transport material on a source moving in one direction, the hole transport layer 132 in a total of one scanning process. The light emitting layer 140 and the electron transport layer 151 can be easily formed.

Hereinafter, the organic light emitting display device of the present invention will be described in detail in the following Examples. However, the following examples are merely to illustrate the present invention is not limited to the following examples.

Example 1

The light emitting area was patterned to a size of 3 mm x 3 mm on the glass substrate and then washed. ITO which is an anode was formed into a film at a thickness of 500 kPa, and CuPc which was a hole injection layer was formed into a film at a thickness of 1000 kPa. The source was provided with NPD as a hole transport material, spiro-PBD as an electron transport material, and Ir (PPY) ₃ as a green phosphorescent dopant. Subsequently, heat was applied to the moving source and scanned to form a hole transport layer at a thickness of 1000 mW, a light emitting layer in which the NPD and spiro-PBD were mixed at a thickness of 300 mW as a green light emitting layer, and an electron transport layer was formed at a thickness of 200 mW. . At this time, the doping concentration of the dopant was 18%, and the mixing ratio of NPD and spiro-PBD of the light emitting layer was 1: 1. Next, LiF, an electron injection layer, was formed to a thickness of 10 GPa, and Al, a cathode, was formed to a thickness of 1000 GPa, to fabricate an organic EL device.

Comparative example

In the same manner as in Example 1, the hole injection layer was formed, and CuPc was formed into a hole transport layer in a chamber provided with one source to a thickness of 1000 kPa. In addition, a light emitting layer was formed on NPD, a host, with a dopant Ir (PPY) ₃ having a thickness of 300 GPa with an 18% doping concentration. Next, spiro-PBD, which is an electron transport layer, was formed to a thickness of 200 mW, a LiF, which was an electron injection layer, was formed to a thickness of 10 mW, and Al was formed to a thickness of 1000 mW to prepare an organic light emitting device.

The driving voltage, the luminous efficiency, the quantum efficiency, and the color coordinates of the organic light emitting diodes manufactured according to Example 1 and Comparative Example were measured and shown in Table 1 below.

Driving voltage
(V) Luminous efficiency
(Cd / A) Color coordinates Quantum Efficiency (%)
CIE_x CIE_y Comparative example 3.6 51.8 0.236 0.718 13.9 Example 1 3.8 76.3 0.248 0.706 20.6

Referring to Table 1 and Figure 5, it can be seen that in Example 1 of the present invention compared to the comparative example the luminous efficiency and quantum efficiency is about 1.5 times improved. That is, in comparison to an organic light emitting device in which one dopant is included in one host as a comparative example, Example 1 of the present invention uses a source provided with two hosts to form a light emitting layer that is a mixture of a hole transport material and an electron transport material. By forming, it was found that the luminous efficiency and the quantum efficiency can be increased.

Example 2

Under the same process conditions as in Example 1, an organic light emitting diode was manufactured by varying the mixing ratio of the hole transport material and the electron transport material to 2: 1.

Example 3

Under the same process conditions as in Example 1, an organic light emitting diode was manufactured by varying the mixing ratio of the hole transport material and the electron transport material to 1: 2.

6 is a graph illustrating the lifespan of the organic light emitting diodes manufactured according to Examples 1, 2, and 3.

Referring to FIG. 6, it can be seen that the life characteristics of the organic light emitting diodes manufactured according to Example 1 are significantly improved compared to the organic light emitting diodes manufactured according to Examples 2 and 3.

That is, as in the first embodiment of the present invention, by forming a mixture ratio of the hole transport material and the electron transport material to act as a host 1: 1, the charge in the light emitting layer is biased on either side and is lost as heat without emitting light deterioration of the device There is an advantage that can be prevented from promoting.

As described above, the organic light emitting display device according to an embodiment of the present invention has an advantage in that the light emitting layer having a mixing ratio of the hole transport material and the electron transport material is 1: 1, thereby greatly improving luminous efficiency and lifetime.

In addition, through the process of scanning the source, there is an advantage that can easily form a hole transport layer, a light emitting layer and an electron transport layer.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be understood that the invention may be practiced. Therefore, the embodiments described above are to be understood as illustrative and not restrictive in all aspects. In addition, the scope of the present invention is shown by the claims below, rather than the above detailed description. Also, it is to be construed that all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts are included in the scope of the present invention.

Claims (7)

Forming a first electrode on the substrate;
Preparing a source in which a hole transport material and an electron transport material are arranged in order on the substrate on which the first electrode is formed;
Scanning the source once while heating the source in a direction in which the hole transport material is disposed, and simultaneously forming a hole transport layer, a light emitting layer that is a mixed layer of the hole transport material and the electron transport material, and an electron transport layer on the first electrode at the same time; ; And
A method of manufacturing an organic light emitting display device comprising the step of forming a second electrode on the light emitting layer.
The method of claim 1,
The source further includes a green phosphorescent dopant material positioned between the hole transport material and the electron transport material,
And depositing the dopant material simultaneously with the deposition of the hole transport material and the electron transport material.
The method of claim 1,
Forming the hole transport layer, the light emitting layer and the electron transport layer that is a mixed layer of the hole transport material and the electron transport material,
Depositing a hole transport material of the source onto the substrate to form a hole transport layer;
Forming the light emitting layer by co-deposition of the hole transport material and the electron transport material by starting deposition of the electron transport material of the source while the hole transport layer is formed; And
The light emitting layer is formed, the method of manufacturing an organic light emitting device comprising the step of depositing only the electron transport material to form an electron transport layer.
The method of claim 1,
Before forming the hole transport layer,
A method of manufacturing an organic light emitting display device, the method comprising: forming a hole injection layer on the first electrode.
The method of claim 1,
Before forming the second electrode,
The method of manufacturing an organic light emitting display device further comprising the step of forming an electron injection layer on the electron transport layer.
The method of claim 1,
The light emitting layer is a manufacturing method of an organic light emitting device having a mixing ratio of the hole transport material and the electron transport material 1: 1.
The method of claim 1,
The scanning of the source starts at one outside of the substrate and ends at the other outside of the substrate.

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