KR100736619B1 - Organic electroluminescence devices - Google Patents

Abstract

The present invention is an organic electroluminescent device comprising a laminate of 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 in order, wherein the light emitting layer comprises an organic electric field comprising a compound of formula (1) It relates to a light emitting device.

[Formula 1]

(A ₁ and A ₂ of Formula 1 are each independently substituted or unsubstituted C ₁ ~ C ₆ aliphatic group, C ₆ ~ C ₂₀ of the aromatic group, C ₅ ~ C ₁₉ including N, S, O Is selected from a heterocyclic group, and A ₃ is a C ₅ to C ₁₉ heteromorphic group including N, S, O, each independently substituted or unsubstituted C ₁ to C ₆ aliphatic group, C ₆ to C ₂₀ aromatic group It is selected from a ring group and hydrogen, wherein the substituents of A ₁ , A ₂ and A ₃ are each one or more, C ₁ ~ C ₁₀ Alkyl, C ₁ ~ C ₁₀ Alkoxy, C ₁ ~ C ₁₀ Alkylamino , C ₁ -C ₁₀ alkylsilyl, halogen, C ₆ -C ₁₀ aryl, C ₆ -C ₁₀ aryloxy, C ₆ -C ₁₀ arylamino, C ₆ -C ₁₀ arylsilyl group and hydrogen Selected from the group consisting of).

Organic light emitting diode

Description

 Organic electroluminescence devices

1 is 4,4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (NPD), copper (II) phthalocyanine (CuPc), tris, which are the compounds used in the Examples of the present invention. Structural formulas of (8-hydroxyquinolate) aluminum (Alq ₃ ), H-1, H-2, H-3 and D-1 are shown.

The present invention relates to an organic electroluminescent device, and more particularly, the present invention includes an organic electroluminescent device comprising a laminate of the anode, the hole injection layer, the hole transport layer, the light emitting layer, the electron transport layer, the electron injection layer and the cathode in order. The present invention relates to an organic electroluminescent device using a green fluorescent compound represented by Chemical Formula 1 as a host and a dopant of a light emitting layer of a device.

Recently, as the size of the display device increases, the demand for a flat display device having less space is increasing. As one of the flat display devices, an organic light emitting diode (OLED), also called an organic light emitting diode (OLED), has a high speed. It has been developed and several prototypes have already been announced.

An organic light emitting display device emits light by injecting charge into an organic film formed between an electron injection electrode (cathode) and a hole injection electrode (anode) and then disappears after pairing electrons and holes. Not only can the device be formed on a flexible transparent substrate such as plastic, but it can also be driven at a lower voltage (10V or less) than a plasma display panel or an inorganic electroluminescent (EL) display. In addition, the power consumption is relatively low, there is an advantage that the color is excellent. In addition, the organic electroluminescent (EL) device can display three colors of green, blue, and red, and thus, has become a subject of much interest as a next-generation rich color display device. Here is a brief look at the process of manufacturing an organic EL device,

(1) First, an anode material is coated on a transparent substrate. Indium tin oxide (ITO) is commonly used as the anode material.

(2) Apply a hole injecting layer (HIL) on it. As the hole injection layer, copper phthalocyanine (CuPc) is mainly coated with a thickness of 10 nm to 30 nm.

(3) Then, introduce a hole transport layer (HTL). As the hole transport layer, 4,4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (4,4'-bis [N- (1-naphthyl) -N-phenylamino] -biphenyl (NPB) is deposited by depositing about 30 nm to 60 nm.

(4) Form an organic emitting layer thereon. At this time, a dopant is added as necessary. Green (green) as a common organic light emitting layer for light emitting tris (8-hydroxy-quinol-rate) aluminum _{(Alq 3) (tris (8} -hydroxy-quinolatealuminum) roneun 30 ~ 60nm thick and depositing approximately a dopant (dopant) MQD (N Methyl quinacridone) (N-Meth ylquinacridone) is used a lot.

(5) An electron transport layer (ETL) and an electron injecting layer (EI L) are successively coated thereon, or an electron injection transport layer is formed thereon. In the case of green light emission, since Alq ₃ in the above (4) has a good electron transport ability, the electron injection layer / transport layer is often not used.

(6) The next cathode is applied and finally the protective film is overlaid.

In the above structure, blue, green, and red light emitting devices may be implemented depending on how the light emitting layer is formed. On the other hand, the material used as a green light emitting compound for implementing a conventional green light emitting device has a problem of poor lifespan and luminous efficiency.

The present invention is to solve the above problems, an object of the present invention by synthesizing the compound of the formula (1) used as a host and dopant of the light emitting layer of the organic light emitting device to obtain a high color purity, high brightness, long life of the organic light emitting device The purpose is to provide.

In order to achieve the above object, the present invention is an organic electroluminescent device formed by sequentially stacking 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, the light emitting layer is represented by the formula An organic electroluminescent device using the green fluorescent compound is provided. When the compound of Formula 1 is used as a dopant of the light emitting layer, the doping concentration is preferably 0.5% by weight to 10% by weight.

A ₁ and A ₂ of Formula 1 are each independently substituted or unsubstituted C ₁ ~ C ₆ aliphatic group, C ₆ ~ C ₂₀ Aromatic group, C ₅ ~ C ₁₉ including a variant of C ₅ ~ C ₁₉ A ₃ is a heterocyclic group of C ₅ to C ₁₉ including C ₁ to C ₆ aliphatic groups, C ₆ to C ₂₀ aromatic groups, N, S, and O, each independently selected from a ring group; Group and hydrogen.

Substituents of A ₁ , A _2, and A ₃ in Formula 1 may each be one or more, and C ₁ ~ C ₁₀ Alkyl, C ₁ ~ C ₁₀ Alkoxy, C ₁ ~ C ₁₀ Alkylamino, C ₁ ~ C ₁₀ alkylsilyl, halogen, C ₆ -C ₁₀ aryl, C ₆ -C ₁₀ aryloxy, C ₆ -C ₁₀ arylamino, C ₆ -C ₁₀ arylsilyl group and hydrogen .

Specific examples of the compound of Formula 1 are as follows.

Hereinafter, a method for synthesizing the green fluorescent compound of the present invention will be described taking as an example a compound represented by G-101 among the green phosphorescent compounds used in the organic light emitting device according to the present invention.

Synthesis Example

1.Synthesis of 2,6-Dibromoanthraquinone

Dissolve 2,6-dibromoanthraquinone (50 g) in 500 mL concentrated HCl in an ice bath in a 1000 mL beaker, slowly drop the NaNO ₂ (25 g) aqueous solution, and raise to room temperature. Then, drop the aqueous solution of KI (25g) slowly and stir at room temperature for 24 hours. After the reaction is completed, filter it and wash it again with water. Then recrystallize it with MC (Methylene Chloride) and MeOH. 2,6-dibromoanthraquinone (30 g) can be obtained.

2. Synthesis of 2,6-Dibromoanthracene

2,6-Dibromoanthraquinone (30 g), Zn (5 g) and NaOH (25 g) were stirred with water (200 mL) for 24 hours at 100 ° C. After the reaction was completed, this was first filtered and the organic and inorganic materials obtained were again After dissolving in chloroform and filtering it again, the filtrate was filtered through a silica gel short column to filter the inorganic material and recrystallized using MC and MeOH again to obtain 2,6-dibromoanthracene (15 g). .

3. Synthesis of G-02

2,6-dibromoanthracene (2 g), 4,4'-ditolylamine (5 g), Pd (OAC) ₂ (0.05 g), BINAP (0.09 g) and NaOtBu (6 g) dissolved in toluene (100 mL) After stirring for 24 hours while refluxing, when the reaction was terminated, toluene was first removed, and then MeOH was added, and this was filtered and the obtained organic material was subjected to a silica gel short column with MC and then recrystallized with MC and MeOH. g) can be obtained.

4. Synthesis of 2,6-Dibromo-9,10-diphenylanthracene

First, phenyllithium (6g) is made in Et ₂ O and then slowly dropped to the place where 2,6-dibromoanthraquinone (5g) is dissolved in Et ₂ O. The reaction proceeds in a dry ice bath. The intermediate is obtained by raising the temperature to room temperature. This can be filtered to give a white solid. After dissolving this in AcOH (100ml), KI and NaH ₂ PO ₂ were added thereto, followed by stirring at 130 ° C for 24 hours. When the reaction is completed, water is added thereto, and the resultant is filtered and recrystallized using MC and MeOH to obtain 2,6-dibromo-9,10-diphenylanthracene (4.5 g).

5. Synthesis of G-68

2,6-dibromo-9,10-diphenylanthracene (4.5 g), 4,4'-ditolylamine (8 g), Pd (OAC) ₂ (0.10 g), BINAP (0.18 g) and NaOtBu (12 g ) Was dissolved in toluene (150 mL), stirred under reflux for 24 hours, and then the reaction was terminated. First, toluene was removed, MeOH was added, and this was filtered, and the obtained organic material was subjected to a silica gel short column with MC and then recrystallized with MC and MeOH. To get G-68 (2.5g).

6. Synthesis of 2,6-Dibromo-9,10-di-1-naphthylanthracene (2,6-Dibromo-9,10-di-1-naphthylanthracene)

First, 1-naphthyllithium (5 g) is made in Et ₂ O and then slowly dropped to the place where 2,6-dibromoanthraquinone (5 g) is dissolved in Et ₂ O. The reaction proceeds in a dry ice bath. The intermediate is obtained by raising the temperature to room temperature. This can be filtered to give a white solid. After dissolving this in AcOH (100ml), KI and NaH ₂ PO ₂ were added thereto, followed by stirring at 130 ° C for 24 hours. When the reaction is completed, water is added thereto, and the mixture is filtered and recrystallized using MC and MeOH to obtain 2,6-dibromo-9,10-di-1-naphthylanthracene (4 g).

7. Synthesis of G-101

2,6-dibromo-9,10-di-1-naphthylanthracene (4 g), 4,4'-ditolylamine (8 g), Pd (OAC) ₂ (0.1 g), BINAP (0.18 g) and After dissolving NaOtBu (12g) in toluene (150mL), stirring under reflux for 24 hours, and then terminating the reaction, first remove the toluene, add MeOH, filter it, and filter the obtained organic matter with silica gel column after MC. Recrystallization with MeOH gives G-101 (2.3 g).

Hereinafter, the present invention will be described in more detail with reference to the following examples. However, it is not limited to the following embodiments of the present invention.

Example

Example 1-20

The light emitting area of the ITO glass was patterned to have a size of 3 mm x 3 mm and then washed. After mounting the substrate in the vacuum chamber, the basic pressure is 1 x 10 ^-6 torr, and the organic material is placed on ITO CuPC (200Å), NPD (400Å), host + dopant (0.5% ~ 10%) (200Å), Alq _The film was formed in the order of ₃ (300 kV), LiF (5 kV), and Al (1000 kV).

Comparative Example 1-3

A device was manufactured in the same manner as in Example 1-20, except for using a dopant other than the compound of the present invention.

The results of Example 1-20 and Comparative Example 1-3 are shown in Table 1 below. The amount of current (mA) measured in the table below is 0.9mA, and the lifetime refers to the lifetime where the initial luminance falls from 1000nits to 500nits.

division Dopant Host Doping concentration Voltage (V) Luminance (cd / m ² ) Current efficiency (cd / A) CIE (X Y) Lifespan (hours) Example 1 G-02 H-1 2% 6.8 1783 17.8 (0.26 0.65) 36,000 Example 2 G-19 H-1 3% 6.8 1692 16.9 (0.27 0.64) 40,000 Example 3 G-36 H-2 3% 6.5 1716 17.1 (0.28 0.65) 35,000 Example 4 G-42 H-3 3% 6.6 1820 18.2 (0.29 0.67) 40,000 Example 5 G-64 H-3 3% 6.5 1905 19.0 (0.31 0.65) 45,000 Example 6 G-68 H-1 One% 6.6 2037 20.4 (0.29 0.66) 55,000 Example 7 G-68 H-1 3% 6.6 2011 20.1 (0.29 0.66) 50,000 Example 8 G-68 H-3 3% 6.5 1968 29.7 (0.29 0.66) 35,000 Example 9 G-78 H-1 3% 6.9 1815 18.1 (0.30 0.66) 38,000 Example 10 G-85 H-1 3% 6.5 2140 21.4 (0.28 0.67) 35,000 Example 11 G-102 H-1 One% 6.4 2065 20.7 (0.31 0.65) 40,000 Example 12 G-116 H-2 3% 6.7 2005 20.0 (0.28 0.67) 40,000 Example 13 G-120 H-2 3% 6.9 2019 20.2 (0.30 0.66) 35,000 Example 14 G-124 H-1 3% 6.4 1956 19.6 (0.27 0.63) 40,000 Example 15 G-131 H-1 3% 6.4 2251 22.5 (0.31 0.64) 40,000 Example 16 G-133 H-1 3% 6.2 2150 22.5 (0.29 0.64) 40,000 Example 17 G-146 H-1 One% 6.3 2269 22.7 (0.31 0.64) 50,000 Example 18 G-146 H-1 3% 6.4 2196 22.0 (0.31 0.64) 50,000 Example 19 G-146 H-2 3% 6.3 2068 20.7 (0.31 0.63) 45,000 Example 20 G-148 H-1 3% 6.4 2093 20.9 (0.28 0.63) 40,000 Comparative Example 1 D-1 H-1 2% 6.6 1608 16.8 (0.34 0.65) 25,000 Comparative Example 2 D-1 H-2 One% 6.3 1638 16.4 (0.33 0.66) 20,000 Comparative Example 3 D-1 H-3 3% 6.7 1520 15.2 (0.36 0.63) 18,000

Example 21-28

The light emitting area of the ITO glass was patterned to have a size of 3 mm x 3 mm and then washed. After mounting the substrate in the vacuum chamber, the basic pressure is 1 x 10 ^-6 torr, and the organic material is placed on ITO CuPC (200Å), NPD (400Å), EML (host) (200Å), Alq ₃ (300Å), LiF (5 microseconds) and Al (1000 microseconds) in order.

Comparative Example 4-5

A device was manufactured in the same manner as in Examples 21-28, except that a host other than the compound of the present invention was used.

The results of Examples 21-28 and Comparative Examples 4-5 are shown in Table 2 below. The amount of current (mA) measured in the table below is 0.9mA, and the lifetime refers to the lifetime where the initial luminance falls from 1000nits to 500nits.

division EML (Host) Voltage (V) Luminance (cd / m ² ) Current efficiency (cd / A) CIE (X Y) Life time (hours) Example 21 G-03 6.9 1233 12.3 (0.44 0.58) 10,000 Example 22 G-12 6.4 1025 10.3 (0.41 0.55) 10,000 Example 23 G-39 7.0 1130 13.0 (0.36 0.58) 8,000 Example 24 G-42 6.8 1164 11.6 (0.37 0.60) 10,000 Example 25 G-68 6.2 1267 12.7 (0.36 0.61) 10,000 Example 26 G-72 6.7 1308 13.1 (0.38 0.60) 8,000 Example 27 G-140 7.1 1207 12.1 (0.37 0.58) 7,000 Example 28 G-153 7.0 1344 13.4 (0.36 0.56) 6,000 Comparative Example 4 Alq ₃ 7.8 786 7.9 (0.37 0.64) 2,000 Comparative Example 5 D-1 8.3 603 6.0 (0.56 0.43) 1,000

The present invention provides an organic electroluminescent device having higher color purity, higher brightness, and longer life than a conventional organic electroluminescent device by using the compound of Formula 1 as a host and a dopant of the light emitting layer of the organic electroluminescent device.

Claims (3)

In the organic electroluminescent device comprising a laminate of 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 in sequence, the light emitting layer comprises a compound of the formula An organic light emitting display device, characterized in that: [Formula 1]

(A ₁ and A ₂ of Formula 1 are each independently substituted or unsubstituted C ₁ ~ C ₆ aliphatic group, C ₆ ~ C ₂₀ of the aromatic group, C ₅ ~ C ₁₉ of including N, S, O Is selected from a heterocyclic group, and A ₃ is a C ₅ to C ₁₉ heteromorphic group including N, S, O, each independently substituted or unsubstituted C ₁ to C ₆ aliphatic group, C ₆ to C ₂₀ aromatic group It is selected from a ring group and hydrogen, wherein the substituents of A ₁ , A ₂ and A ₃ are each one or more, C ₁ ~ C ₁₀ Alkyl, C ₁ ~ C ₁₀ Alkoxy, C ₁ ~ C ₁₀ Alkylamino , C ₁ -C ₁₀ alkylsilyl, halogen, C ₆ -C ₁₀ aryl, C ₆ -C ₁₀ aryloxy, C ₆ -C ₁₀ arylamino, C ₆ -C ₁₀ arylsilyl group and hydrogen Selected from the group consisting of). The method of claim 1, The light emitting layer is an organic light emitting device, characterized in that using the compound of Formula 1 as a host or dopant of the light emitting layer. The method of claim 2, Doping concentration of the dopant is an organic light emitting device, characterized in that 0.5% to 10% by weight.

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