KR101103488B1 - Light emitting device and Method for manufacturing the same - Google Patents

Abstract

In the present invention, since the polymer layer of the electroluminescent device contains a photosensitive crosslinking agent, the pattern formation by the photomask is good, and the light is cured by light, thereby improving chemical resistance to the organic solvent, and thus electroluminescence without erosion in the organic thin film layer formation process. An element and a method of manufacturing the same. Electroluminescent device of the present invention is an anode; A polymer layer comprising a crosslinking agent; And a cathode.

Description

Light emitting device and method for manufacturing the same

The present invention relates to an electroluminescent device and a method of manufacturing the same, and more particularly, to an electroluminescent device excellent in chemical resistance and easy to form a pattern and a method of manufacturing the same.

In recent years, research on advanced displays has been actively conducted, and one of the most attracting fields is organic light emitting diodes (OLEDs). Unlike the liquid crystal display (LCD), which is the mainstream of the current display device, the organic light emitting device does not need a backlight because it is a self-luminous type, and has an excellent light viewing angle, an ultra-light and ultra-thin, low power consumption, and a large contrast ratio. In addition, the organic light emitting device has a high response speed and high resolution has the advantage of easy video playback. In addition, since the organic light emitting device can be coated on a plastic substrate, a thin and flexible display can be manufactured.

However, the organic electroluminescent device manufactured using the low molecular weight organic material is easy to manufacture in a multilayer structure because it can form a thin film through vacuum deposition, while the manufacturing process is difficult and the manufacturing cost is expensive.

Instead of using low molecular weight organic materials, polymer light emitting diodes (PLEDs) manufactured using high molecular weight organic materials are manufactured by forming a thin film through a solution process such as spin coating or inkjet coating. The process is simple, the manufacturing cost is low, and there is an advantage in that a large panel display can be easily manufactured.

Polymer electroluminescent devices have been developed since 1990, when the University of Cambridge, UK, discovered that electrons were emitted when conductive electrons were poured into poly (1,4-phenylenevinylene).

The polymer electroluminescent device basically comprises a positive electrode, a negative electrode and a polymer layer interposed between the positive electrode and the negative electrode, the anode mainly consists of indium titanium oxide (indium / tinoxide) coated on the glass, The cathode is made of Ca, Mg or Al having a low work function, and the polymer layer is prepared by spin coating a polymer solution on an ITO substrate, has a thickness of about 100 nm, and is in contact with the cathode on the top.

Initially, the polymer electroluminescent device was composed of only an anode, a light emitting layer, and a cathode, but recently has a multilayer structure of three or more layers in order to increase efficiency, lifespan, and brightness. For example, the polymer electroluminescent device may have a multilayer form including an anode, a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, an electron injection layer, and a cathode.

However, the polymer used in the injection layer, the transport layer and the light emitting layer of the conventional electroluminescent device has a problem that erosion occurs in the process of forming the organic thin film layer as it is easily dissolved in a conventional organic solvent.

In addition, the polymer used in the injection layer, the transport layer and the light emitting layer of the conventional electroluminescent device has a problem in that the pattern formation by the photomask is complicated.

The present invention has been derived to solve the above problems, the present invention, the polymer layer of the electroluminescent device comprises a photosensitive crosslinking agent to form a pattern by the photomask is good and hardened by light to the organic solvent It is an object of the present invention to provide an electroluminescent device and a method of manufacturing the same, wherein the chemical property is improved and erosion does not occur in the process of forming an organic thin film layer.

The present invention, in order to achieve the above object, in one aspect of the present invention, an anode; A polymer layer comprising a crosslinking agent; And it provides an electroluminescent device comprising a cathode.

In another aspect of the present invention, a process for forming an anode; Forming a polymer layer containing a crosslinking agent; And it provides a method of manufacturing an electroluminescent device comprising the step of forming a cathode on the polymer layer.

The present invention has the following effects.

First, since the electroluminescent device according to the present invention can easily form a pattern through a photomask by including a crosslinking agent, there is an effect of simplifying the process.

Second, the electroluminescent device according to the present invention may be easily cured by light irradiation by having a polymer layer including a crosslinking agent, and thus the cured polymer layer is excellent in resistance to organic solvents in the process of forming an organic thin film layer. It is effective to prevent erosion.

The electroluminescent device having such excellent pattern formation and chemical resistance can be used in various fields.

1 is a schematic cross-sectional view of an electroluminescent device according to an embodiment of the present invention.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention. Therefore, the present invention encompasses all changes and modifications that come within the scope of the invention as defined in the appended claims and equivalents thereof.

First, the electroluminescent device 100 of the present invention will be described in detail.

1 is a schematic cross-sectional view of an electroluminescent device 100 according to an embodiment of the present invention. As shown in FIG. 1, the electroluminescent device 100 of the present invention includes a polymer layer 30. The polymer layer 30 includes a crosslinking agent. The crosslinking agent may be an azide compound represented by Formula 1 below.

[Formula 1]

N ₃ -RN ₃

In this case, R has a carbon number of 1 to 30.

The polymer layer 30 may include a fluorene-based polymer. In addition, the polymer layer 30 may include a triphenylamine-based polymer. In addition, the polymer layer 30 may include a carbazole-based polymer.

The polymer layer 30 may be a single layer composed of a light emitting layer 33. In addition, the polymer layer 30 may be a multilayer including an emission layer 33. That is, the light emitting layer 33 may include at least one of the hole injection layer 31, the hole transport layer 32, the hole suppression layer 34, the electron transport layer 35, and the electron injection layer 36. It may be a polymer layer 30 formed in multiple layers.

The hole injection layer 31 may include a compound which is at least one of copper phthalocyanine (CuPC), a triamine compound, an anthracene compound, a thiophene compound, and a cyclohexane compound in which three pyrazine rings are fused. It is not necessarily limited thereto.

The hole transport layer 32 may include at least one of a polyphenylvinylene-based compound, a polyfluorene-based compound, and a polycarbazole-based derivative, but is not necessarily limited thereto.

The light emitting layer 33 may include a polyfluorene compound, a polyphenylene compound, a polyphenylene vinylene compound, a polythiophene compound, a polyquinoline compound, a polypyrrole compound, a polyacetylene compound, and a spirofluorene compound (For example, a spirofluorene compound including an indenofluoroene repeat unit having a spiranthracene structure), a cyclopentaphenanthrene compound, and a polyarylene compound containing an indolecarbazole unit or a phenoxazine unit It may include at least one compound, but is not necessarily limited thereto.

The electron transport layer 35, tris (8-quinolinorate) aluminum (Alq3), TAZ, or Balq may include a quinoline derivative compound formed in the branch or main chain, but is not necessarily limited thereto.

The electron injection layer 36 may include LiF, NaCl, CsF, Li ₂ O, or BaO, but is not necessarily limited thereto.

Both sides of the polymer layer 30 are formed with a positive electrode 20 and a negative electrode 40. The anode 20 is formed on the substrate 10. The substrate 10 may be a glass substrate 10 or a transparent plastic substrate 10 having excellent mechanical strength, thermal stability, transparency, surface smoothness, ease of handling, and waterproofness.

The positive electrode 20 includes lithium (Li), magnesium (Mg), aluminum (Al), calcium (Ca), indium (In), silver (Ag), indium tin oxide (ITO), and indium zinc oxide (IZO). , At least one of tin oxide (SnO 2) and zinc oxide (ZnO), a metal oxide, or a mixture thereof.

The negative electrode 40 includes lithium (Li), magnesium (Mg), barium (Ba), aluminum (Al), aluminum-lithium (Al-Li), aluminum-barium (Al-Ba), calcium (Ca), At least one of magnesium-indium (Mg-In), and magnesium-silver (Mg-Ag), a metal oxide, or a mixture thereof.

On the other hand, the positive electrode 20 and the negative electrode 40 is not necessarily limited to the compound.

The anode 20 and the cathode 40 may be formed by vacuum deposition or sputtering.

The polymer layer 30 may be in a form cured by light irradiation. The light may be ultraviolet light.

Meanwhile, the polymer layer 30 may form a cyclic compound by light irradiation. The cyclic compound may be mainly formed by an intramolecular reaction.

The polymer layer 30 cured as described above is not easily dissolved in a common organic solvent, such as toluene, xylene, anisole, benzene or methylbenzoate. That is, since the cured polymer layer 30 has a very high resistance to organic solvents, erosion does not occur during the formation of the organic thin film layer, and thus the electroluminescent device 100 having excellent performance may be manufactured.

Next, the manufacturing method of the electroluminescent device 100 will be described in detail.

Description of overlapping parts of the above-described electroluminescent device 100 will be omitted.

First, the substrate 10 is prepared. As the substrate 10, a glass substrate 10 or a transparent plastic substrate 10 having excellent mechanical strength, thermal stability, transparency, or ease of handling may be used.

Subsequently, an anode 20 is formed on the substrate 10. The anode 20 may be a metal having a high work function, a metal oxide, or a mixture thereof. The anode 20 may be formed as a reflective electrode or a transmissive electrode, and various modifications are possible.

Subsequently, the polymer layer 30 is formed on the anode 20.

The polymer layer 30 may be a single layer made of the light emitting layer 33 or may be a multilayer of two or more layers including the light emitting layer 33. That is, the multilayer polymer layer 30 includes a hole injection layer 31, a hole transport layer 32, a hole suppression layer 34, an electron transport layer 35, and an electron injection layer 36 in addition to the light emitting layer 33. At least one of the layers may be stacked in order.

The light emitting layer 33 is a conventional organic solvent, toluene, xylene, o-xylene, m-xylene, anisole, 1,2,4-trimethylbenzene (1,2,4-trimethylbenzene) or methyl After preparing a light emitting polymer composition by dissolving a light emitting polymer in benzoate (methylbenzoate), etc., the light emitting polymer composition is applied onto a hole injection layer 31 to be described later, and dried at 50 to 200 ° C. to remove a solvent. Can be formed.

The wet process may include a spin coating method, an inkjet printing method, a nozzle printing method, a spray printing method, or the like.

The thickness of the light emitting layer 33 may be 100 to 2000 mm 3, preferably 200 to 1000 mm 3. If the thickness of the light emitting layer 33 is less than 100 μs, the light emission performance may be reduced. On the other hand, if the thickness of the light emitting layer 33 exceeds 2000 μs, the driving voltage may increase.

The hole injection layer 31 and the hole transport layer 32 is located between the anode 20 and the light emitting layer 33, and serves to help the holes supplied from the anode 20 to smoothly reach the light emitting layer 33. do. The hole injection layer 31 and the hole transport layer 32 may be insoluble in the organic solvent used to form the light emitting layer 33, that is, it may be insoluble. As a result, the hole injection layer 31 or the hole transport layer 32 may be prevented from being damaged and lost in the organic solvent in the process of forming the light emitting layer 33. Therefore, the electroluminescent device 100 including the hole injection layer 31 and the hole transport layer 32 which are insoluble in organic solvents may have advantages of long life and excellent efficiency.

The hole injection layer 31 and the hole transport layer 32 is a vacuum deposition method, spin coating method, inkjet printing method, nozzle printing method, spray printing method, organic vapor jet printing method, organic vapor phase deposition method, cast method, LB method It can be formed through.

The vacuum deposition method may be performed in the range of 100 to 500 ° C., 10 ⁻⁸ to 10 ⁻³ torr, and 0.01 to 100 μs / sec, depending on the structure and thermal properties of the compound to be used.

The hole injection layer 31 may have a thickness of 50 to 10000 mm, preferably 50 to 1000 mm. If the thickness of the hole injection layer 31 is less than 50 μm, holes may not be injected smoothly. If the thickness of the hole injection layer 31 exceeds 1000 μm, the driving voltage may increase.

The hole transport layer 32 may have a thickness of 50 to 2000 mm 3, preferably 100 to 1500 mm 3. If the thickness of the hole transport layer 32 is less than 50 μm, holes may not be smoothly transported. If the thickness of the hole transport layer 32 exceeds 2000 μm, the driving voltage may increase.

The hole suppression layer 34 is formed on the light emitting layer 33 and prevents holes flowing into the light emitting layer 33 from flowing to the cathode 40. The hole suppression layer 34 may be formed by vacuum deposition, spin coating, inkjet printing, nozzle printing, spray printing, organic vapor jet printing, organic vapor phase deposition, cast, or LB. .

The hole suppression layer 34 may have a thickness of 50 to 1000 mm 3, preferably 100 to 300 mm 3. When the thickness of the hole suppression layer 34 is less than 50 kV, the hole suppression performance may be reduced, and when the thickness of the hole suppression layer 34 exceeds 1000 kV, the driving voltage may increase.

The electron transport layer 35 is formed on the hole suppression layer 34 and serves to smoothly supply electrons supplied from the cathode 40 to the light emitting layer 33. The electron transport layer 35 may be formed by a vacuum deposition method, a spin coating method, an inkjet printing method, a nozzle printing method, a spray printing method, an organic vapor jet printing method, an organic vapor phase deposition method, a cast method, or an LB method. .

The spin coating method may be performed at a coating speed of 2000 to 5000 rpm and a drying temperature of 80 to 200 ° C., depending on the structure and thermal properties of the compound.

The electron transport layer 35 may have a thickness of 100 to 1000 mm, preferably 200 to 500 mm. If the thickness of the electron transport layer is less than 100 kW, the electron transport performance may be degraded. On the other hand, if the thickness of the electron transport layer 35 exceeds 1000 kW, the driving voltage may increase.

The electron injection layer 36 is formed on the electron transport layer 35 and serves to easily inject electrons from the cathode 40. The electron injection layer 36 may be formed by vacuum deposition.

The vacuum deposition method may be performed at a deposition rate of 0.01 to 1 dl / sec. If the deposition rate is less than 0.01 μs / sec, not only it is difficult to accurately control the layer thickness, but also the deposition time may be increased, whereas if the deposition rate exceeds 1 μs / sec, it is difficult to accurately control the layer thickness. It can be difficult.

The electron injection layer 36 may have a thickness of 1 to 500 kPa, and preferably 5 to 50 kPa. If the thickness of the electron injection layer 36 is less than 1 kW, the electron injection performance may decrease. On the other hand, if the thickness of the electron injection layer exceeds 500 kW, the driving voltage may increase.

The polymer layer 30 may be cured by light irradiation. That is, the polymer layer may be easily cured by light irradiation such as ultraviolet rays, as described above, including the crosslinking agent. On the other hand, the polymer layer 30 may be a cyclization reaction by light irradiation, thereby forming a ring compound. The cyclization reaction may be predominantly an intramolecular reaction.

The polymer layer 30 may form a pattern well through a photomask. That is, a pattern may be easily formed on the polymer layer 30 through a process of placing a photomask on the polymer layer 30 including the crosslinking agent and exposing the same, and developing the same with a solvent such as toluene.

Hereinafter, the effects of the present invention will be described in more detail with reference to the following examples. These Examples and Experimental Examples are merely to aid the understanding of the present invention and do not limit the scope of the present invention.

Example

After cutting the substrate 10 (manufactured by SDI) having a thickness of 50 mm x 50 mm x 0.7 mm coated with the anode 20 made of aluminum and indium tin oxide, 50 mm x 50 mm x 0.7 mm, respectively, in isopropyl alcohol and pure water, 5 After ultrasonic cleaning for minutes, ultraviolet rays are irradiated for 30 minutes and ozone is cleaned to prepare the substrate 10 having the anode 20 formed thereon.

Subsequently, a hole injection having a thickness of 1000 하여 is formed by spin coating a polymer composition obtained by dissolving a polyfluorene compound represented by the following Chemical Formula 2 and a 5 wt% photosensitive crosslinking agent represented by the following Chemical Formula 3 in toluene on the anode 20. Layer 31 is formed.

[Formula 2]

(3)

Subsequently, on the hole injection layer 31, a light emitting layer having a thickness of 500 mm by spin coating a polymer composition obtained by dissolving a polyfluorene-based polymer (manufactured by Dow Chemical Company) and 5% by weight of the photosensitive crosslinking agent of Formula 3 in toluene 33 is formed.

Subsequently, a polybenzimidazobenzophenanthroline (manufactured by Sigma aldrich) and 5 wt% of the photosensitive crosslinking agent of Formula 3 dissolved in toluene was spin coated on the light emitting layer 33 to have a thickness of 500 mV. The electron transport layer 35 is formed.

Subsequently, a photomask is placed on the electron transport layer 35 and selectively transmitted through ultraviolet light, cured, and then developed with toluene. Then, lithium fluoride (LiF) is deposited on the electron transport layer 35 to a thickness of 3 kPa. After vacuum deposition to form the electron injection layer 36, magnesium-silver (Mg-Ag) was vacuum deposited to a thickness of 180 kHz to manufacture an electroluminescent device (100).

In the electroluminescent device 100 manufactured as described above, it was found that the hole injection layer, the light emitting layer 33, and the electron transporting layer were hardly damaged as a result of cross-sectional confirmation. In addition, the electroluminescent device 100 was confirmed to have a long life and high efficiency.

10 substrate 20 anode
30: polymer layer 40: cathode
100: electroluminescent device

Claims (26)

anode;
A polymer layer comprising a crosslinking agent; And
A cathode;
The crosslinking agent includes a compound represented by the following Formula 1,
[Formula 1]
N ₃ -RN ₃
(Wherein R has 1 to 30 carbon atoms),
The polymer layer is an electroluminescent device, characterized in that the ring is generated by an intramolecular reaction. The method of claim 1,
The polymer layer is an electroluminescent device comprising a fluorene-based polymer. The method of claim 1,
The polymer layer is an electroluminescent device comprising a triphenylamine-based polymer. The method of claim 1,
The polymer layer is an electroluminescent device comprising a carbazole-based polymer. delete The method of claim 1,
The polymer layer is an electroluminescent device, characterized in that the hole injection layer. The method of claim 1,
The polymer layer is an electroluminescent device, characterized in that the hole transport layer. The method of claim 1,
The polymer layer is an electroluminescent device, characterized in that the light emitting layer. The method of claim 1,
The polymer layer is an electroluminescent device, characterized in that the electron transport layer. The method of claim 1,
The polymer layer is an electroluminescent device, characterized in that the electron injection layer. The method of claim 1,
The polymer layer is electroluminescent device, characterized in that cured by light irradiation. delete delete The method of claim 1,
The anode is an electroluminescent device, characterized in that formed on the glass substrate or a transparent plastic substrate. Forming an anode;
Forming a polymer layer containing a crosslinking agent; And
Forming a cathode in the polymer layer,
The crosslinking agent includes a compound represented by the following Formula 1,
[Formula 1]
N ₃ -RN ₃
(Wherein R has 1 to 30 carbon atoms),
The polymer layer is a method of manufacturing an electroluminescent device, characterized in that the ring is generated by the intramolecular reaction. 16. The method of claim 15,
The polymer layer is a method of manufacturing an electroluminescent device comprising a fluorene (fluorene), triphenylamine-based or carbazole-based polymer. delete 16. The method of claim 15,
The step of forming the polymer layer is a method of manufacturing an electroluminescent device comprising a step of curing by light irradiation. The method of claim 18,
The hardening process is a method of manufacturing an electroluminescent device, characterized in that carried out through ultraviolet irradiation. delete The method of claim 18,
The step of curing the polymer layer is a method of manufacturing an electroluminescent device comprising the step of forming a pattern through a photomask. 16. The method of claim 15,
The process of forming the polymer layer comprises the step of forming at least one of a hole injection layer, a hole transport layer, a light emitting layer, a hole suppression layer, an electron transport layer, an electron injection layer. The method of claim 22,
The light emitting layer is dissolved in an organic solvent of toluene, xylene, o-xylene, m-xylene, anisole, 1,2,4-trimethylbenzene or methylbenzoate. Method for producing an electroluminescent device, characterized in that. The method of claim 22,
The hole injection layer and the hole transport layer is toluene, xylene, o-xylene, m-xylene, anisole, 1,2,4-trimethylbenzene (1,2,4-trimethylbenzene) or methylbenzoate (methylbenzoate) Method for producing an electroluminescent device, characterized in that it is not dissolved in an organic solvent. The method of claim 22,
Forming the light emitting layer is a method of manufacturing an electroluminescent device, characterized in that carried out through a wet process. The method of claim 22,
The process of forming the hole injection layer, the hole transport layer, the hole suppression layer, and the electron transport layer is a vacuum deposition method, spin coating method, inkjet printing method, nozzle printing method, spray printing method, organic vapor jet printing method, organic vapor phase deposition method, Method of manufacturing an electroluminescent device, characterized in that carried out through the cast method, or LB method.

Images