KR20120038818A - Red color phosphorescent host material and organic electroluminescent display device using the same - Google Patents

Abstract

PURPOSE: Red phosphorescence host material is provided to form a film by solution process, because of excellent solubility, thereby offering large size organic electroluminescence device capable of embodying image with high luminance. CONSTITUTION: Red phosphorescence host material is in chemical formula 1 or 2. In chemical formulas, A is substituted or unsubstituted aromatic group material, substituted or unsubstituted heterocyclic group material, substituted or unsubstituted aromatic group bacterial, or hydrogen. An organic electroluminescence device comprises a first electrode, a second electrode facing the first electrode, and a light emitting material layer between the first and the second electrode. The light emitting material layer consists of the red phosphorescence host material.

Description

Red phosphorescent host material and Organic electroluminescent display device using the same

The present invention relates to a red phosphorescent host material and an organic light emitting device using the same. More specifically, the present invention relates to a red phosphorescent host material that can be dissolved and has excellent brightness and luminous efficiency, and an organic light emitting device comprising the same.

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) technology, also called an organic light emitting diode (OLED), has a high speed. It has been developed and several prototypes have already been announced.

The organic electroluminescent device is a device that emits light when electrons and holes are paired and then disappear when electrons are injected into the light emitting material layer formed between the electron injection electrode (cathode) and the hole injection electrode (anode). 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 (less than 10V) compared to 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 light emitting device,

(1) First, a material such as indium tin oxide (ITO) is deposited on a transparent substrate to form an anode.

(2) forming a hole injecting layer (HIL) on the anode; The hole injection layer is formed by mainly depositing copper phthalocyanine (CuPc) represented by Chemical Formula 1-1 to a thickness of 10 nm to 30 nm.

(3) Next, a hole transport layer (HTL) is formed on the hole injection layer. This hole transport layer is formed by depositing about 30nm to 60nm 4,4'-bis [N- (1-naphtyl) -N-phenylamino] -biphenyl (NPD) represented by the following formula (1-2).

(4) Next, an emitting material layer (EML) is formed on the hole transport layer. At this time, a dopant is added as necessary.

For example, in the light emitting material layer, a red light emitting layer, a green light emitting layer, and a blue light emitting layer constitute one pixel to express various grayscales. For example, the red light emitting layer may deposit 4, 4′-N, N′-dicarbazolbiphenyl (CBP) represented by the following Chemical Formula 1-3 in a thickness of 30 nm to 60 nm, and as a dopant. Iridium complexes represented by -4 or 1-5 are mainly used.

(5) Next, an electron transport layer (ETL) and an electron injecting layer (EIL) are successively formed on the light emitting material layer. In this case, the electron transport layer is made of tris (8-hydroxy-quinolate) aluminum (Alq3) represented by the following Chemical Formula 1-6.

(6) Next, a cathode is formed on the electron injection layer, and finally a protective film is formed on the cathode.

Formula 1 -One

Formula 1 -2

Formula 1 -3

Formula 1 -4

Formula 1 -5

Formula 1 -6

In the structure as described above, the light emitting material layer implements blue, green, and red to realize full color images.

In the case of the light emitting material, excitons are formed by recombination of electrons and holes injected from both electrodes, and singlet excitons are involved in phosphorescence and triplet excitons. The triplet excitons with 75% generation probability involved in the phosphorescent material exhibit better luminous efficiency than the fluorescent materials using singlet excitons with 25% generation probability. Among these phosphorescent materials, red phosphorescent materials may have a very high luminous efficiency compared to fluorescent materials, and thus, many researches have been conducted as important methods for increasing the efficiency of organic light emitting diodes.

In order to use phosphorescent materials, high luminous efficiency, high color purity, and long light emitting lifetime are required, and in the case of red color, as the color purity increases (as CIE color coordinate X value increases) as shown in FIG. There is a problem in that efficiency is difficult to obtain high luminous efficiency. Accordingly, there is a demand for the development of a red phosphor having excellent color purity (CIE color purity X = 0.65 or more) and high luminous efficiency.

On the other hand, CBP or a metal complex (metal complex) is used as the red phosphorescent host material, but these materials are poor in solubility and thus have to be formed through a deposition process, which has a disadvantage in that process efficiency is lowered.

In particular, it has a big limitation in forming a large area element.

An object of the present invention is to provide a red phosphorescent host material having excellent solubility, capable of solution processing, and excellent brightness and luminous efficiency.

In addition, an object of the present invention is to provide a large area organic light emitting display device capable of realizing a high brightness image using the red phosphorescent host material.

In order to solve the above problems, the present invention is represented by the following formula (1) or (2), A is a substituted or unsubstituted aromatic group material, a substituted or unsubstituted heterocyclic group material, a substituted or unsubstituted aromatic group material It provides a red phosphorescent host material for an organic light emitting device, characterized in that selected from, or hydrogen.

Formula 1

Formula 2

The aromatic group material is characterized by including phenyl, naphthyl, biphenyl, terphenyl, phenanthrenyl.

The heterocyclic group material may be pyridinyl, bipyridinyl, quinolinyl, isoquinolinyl, quinoxalinyl, terpyridinyl, phenoxrollinyl ( phenanthrolinyl).

The aliphatic group material is characterized in that it comprises C1 ~ C20 aryl (aryl), C1 ~ C20 alkyl (alkyl).

Substituents of each of the aromatic group material, the heterocyclic group material and the aromatic group material are C1 ~ C20 aryl, C1 ~ C20 alkyl, C1 ~ C20 alkoxy, halogen , Cyano, silyl is selected.

In another aspect, the first electrode; A second electrode facing the first electrode; And a light emitting material layer positioned between the first and second electrodes, wherein the light emitting material layer is represented by the following Chemical Formula 1 or Chemical Formula 2, A is a substituted or unsubstituted aromatic group material, a substituted or unsubstituted An organic electroluminescent device characterized by consisting of a red phosphorescent host material characterized by being selected from a heterocyclic group material, a substituted or unsubstituted aromatic group material, or hydrogen.

Formula 1

Formula 2

The red phosphorescent host material is soluble in a nonpolar solvent and is formed by a coating process.

Since the red phosphorescent host material of the present invention has excellent solubility, the red phosphorescent host material has an advantage in that a film can be formed by a solution process. Accordingly, it is easy to manufacture a large area organic light emitting display device.

In addition, the organic light emitting display device using the red phosphorescent host material may realize a high brightness image and reduce power consumption.

1 is a graph showing a relationship between color purity and visibility (relative sensitivity) of an organic light emitting display device.
2 is a schematic cross-sectional view of an organic light emitting display device according to an embodiment of the present invention.

Hereinafter, a structure of a red phosphorescent host material according to the present invention, a synthesis example thereof, and an organic light emitting display device using the same will be described.

First embodiment

In the red phosphorescent host material according to the first exemplary embodiment of the present invention, a benzo group is positioned at positions 3 and 4, and a substance selected from an aromatic group, a heterocyclic group, an aliphatic group, or hydrogen is substituted at position 6 and is positioned at position 9 Carbazol in which a phenyl group is substituted is symmetrically substituted with biphenyl, and is characterized by having soluble properties, and is represented by the following Chemical Formula 2. The nitrogen of the carbazole is substituted at the para position of the phenyl group.

Formula 2

In Formula 2, A is selected from a substituted or unsubstituted aromatic group material, a substituted or unsubstituted heterocyclic group material, a substituted or unsubstituted aromatic group material, or hydrogen.

For example, the aromatic group material includes phenyl, naphthyl, biphenyl, terphenyl, and phenanthrenyl.

In addition, the heterocyclic group material is pyridinyl, bipyridinyl, quinolinyl, isoquinolinyl, quinoxalinyl, terpyridinyl, terpyridinyl, phenanthrol It is characterized by the inclusion of phenanthrolinyl.

In addition, the aliphatic group material is characterized by containing C1 ~ C20 aryl, C1 ~ C20 alkyl.

In addition, the substituents of each of the aromatic group material, the heterocyclic group material and the aromatic group material may be C1 to C20 aryl, C1 to C20 alkyl, C1 to C20 alkoxy, halogen ( It is characterized by being selected from halogen, cyano and silyl. For example, the substituent is methyl, ethyl, propyl, isopropyl, butyl (t-butyl), methoxy, ethoxy, butoxy ( butoxy), trimethylsilyl, fluorine, and chlorine.

That is, in the red phosphorescent host material of the first embodiment, a benzo group is placed at positions 3 and 4, and a substance selected from an aromatic group, a heterocyclic group, an aliphatic group, or hydrogen is substituted at position 6 and phenyl is positioned at position 9; Carbazol substituted with a (phenyl) group is symmetrically substituted with biphenyl, and nitrogen of the carbazole is substituted at the para position of the phenyl group, thereby having a soluble property.

For example, in Formula 2, A may be selected from a plurality of substance groups represented by Formula 3 below.

(3)

According to the selection of A, the red phosphorescent host material of Chemical Formula 2 is any one of a plurality of materials represented by Chemical Formula 4 below. Here, for the convenience of explanation, symbols of A01 to A38 are given at the bottom of each material.

Formula 4

Hereinafter, among the red phosphorescent host materials for organic electroluminescent devices according to the first embodiment of the present invention, the red phosphorescent host materials represented by A-01 and A-02 in Chemical Formula 4 will be exemplified. Explain 2.

First Synthetic example

1.Synthesis of 2,2'-biphenyldiboronic acid

2,2'-biphenyldiboronic acid is synthesized by Reaction 1 below.

Scheme 1

Specifically, 2,2'-dibromobiphenyl (10 g, 0.03 mol) and 100 mL of ether are put into a 2-round flask and stirred. After the temperature was lowered to -78 ° C by dry-ice bath, 2.5M n-BuLi (26.9mL, 0.067mol) was slowly dropped and stirred for 1 hour at room temperature. Lower the temperature to -78 ℃ again with a dry-ice bath, slowly drop triethylborate (19.5g, 0.13mol) and stir again at room temperature for 4 hours. 100 mL of 2N HCl is added and the reaction is quenched, and then the solvent is evaporated. The resulting solid was filtered and washed 3-4 times with distilled water and hexane to give 2,2'-biphenyldiboronic acid (5.4 g, yield: 70%).

2. Synthesis of 2,2'-bis (4'-bromophenyl) biphenyl

2,2'-bis (4'-bromophenyl) biphenyl is synthesized by Scheme 2 below.

Scheme 2

Specifically, 2,2'-biphenyldiboronic acid (5g, 0.02mol), 1-bromo-4-iodobenzene (12.9g, 0.045mol), Pd (PPh3) 4 (0.1g, 0.9mmol), Add 90 mL of toluene / EtOH (3: 1) with K2CO3 and reflux for 12 hours. The temperature was cooled to room temperature, extracted with methylene chloride, the solvent was evaporated, and purified by silica gel column to purify the 2,2'-bis (4'-). bromophenyl) biphenyl (7.8g, yield: 80%) was obtained.

3. Synthesis of A-01

The red phosphorescent host material represented by A-01 in Chemical Formula 4 is synthesized by the following Scheme 3.

Scheme 3

Specifically, 2,2'-bis (4'-bromophenyl) biphenyl (1g, 2.1mmol), benzo [3,4] carbazole (1g, 4.7mmol), Pd2 (dba) 3, P ( t-Bu) 3, NaOBu (0.6 g, 6 mmol) and toluene were added and refluxed at 130 ° C. for 18 hours. After cooling to room temperature, the mixture was extracted with methylene chloride, the solvent was evaporated, and purified by silica gel column to obtain A-01 (1.1 g, yield: 70%).

2nd Synthetic example

1.Synthesis of 2,2'-biphenyldiboronic acid

2,2'-biphenyldiboronic acid is synthesized according to Scheme 4 below.

Scheme 4

Specifically, 2,2'-dibromobiphenyl (10 g, 0.03 mol) and 100 mL of ether are put into a 2-round flask and stirred. After the temperature was lowered to -78 ° C by dry-ice bath, 2.5M n-BuLi (26.9mL, 0.067mol) was slowly dropped and stirred for 1 hour at room temperature. Lower the temperature to -78 ℃ again with a dry-ice bath, slowly drop triethylborate (19.5g, 0.13mol) and stir again at room temperature for 4 hours. 100 mL of 2N HCl was added to terminate the reaction, and the solvent was evaporated. The resulting solid was filtered and washed 3-4 times with distilled water and hexane to give 2,2'-biphenyldiboronic acid (5.4 g, yield: 70%).

2. Synthesis of 2,2'-bis (4'-bromophenyl) biphenyl

2,2'-bis (4'-bromophenyl) biphenyl is synthesized by Scheme 5 below.

Scheme 5

Specifically, 2,2'-biphenyldiboronic acid (5g, 0.02mol), 1-bromo-4-iodobenzene (12.9g, 0.045mol), Pd (PPh3) 4 (0.1g, 0.9mmol), Add 90 mL of toluene / EtOH (3: 1) with K2CO3 and reflux for 12 hours. The temperature was cooled to room temperature, extracted with methylene chloride, the solvent was evaporated, and purified by silica gel column to purify the 2,2'-bis (4'-). bromophenyl) biphenyl (7.8g, yield: 80%) was obtained.

3. Synthesis of A-02

The red phosphorescent host material represented by A-02 in Chemical Formula 4 is synthesized by the following Scheme 6.

Scheme 6

Specifically, 2,2'-bis (4'-bromophenyl) biphenyl (1g, 2.1mmol), 3-phenylbenzo [3,4] carbazole (1g, 4.7mmol), Pd2 (dba) 3, P (t-Bu) 3, NaOBu (0.6 g, 6 mmol) and toluene were added and refluxed at 130 ° C. for 18 hours. After cooling to room temperature, the mixture was extracted with methylene chloride, the solvent was evaporated, and purified by silica gel column to obtain A-02 (1.1 g, yield: 70%).

Hereinafter, the red phosphorescent host material according to the present invention and the organic field using the same through Experimental Examples 1 to 5 to fabricate the organic light emitting device using the red phosphorescent host material according to the first embodiment of the present invention. The performance of a light emitting element is compared and demonstrated.

Experimental Example 1

The light emitting area of the indium tin oxide (ITO) layer on the substrate was patterned to have a size of 3 mm x 3 mm and then washed. The ITO layer CuPC (650 kPa), NPD (400 kPa), a light emitting layer (200 kPa) containing 5% of a dopant represented by RD-1 in Chemical Formula 1-4 to the red phosphorescent host material represented by A-01 in Chemical Formula 4, Alq3 It formed into a film in order of (350 Pa), LiF (5 Pa), and Al (1000 Pa).

1150cd / m2 (5.8V) at 0.9mA, where CIE x = 0.658 and y = 0.327.

Experimental Example 2

The light emitting area of the indium tin oxide (ITO) layer on the substrate was patterned to have a size of 3 mm x 3 mm and then washed. The ITO layer CuPC (650 kPa), NPD (400 kPa), a light emitting layer (200 kPa) containing 5% of a dopant represented by RD-1 in Chemical Formula 1-4 to the red phosphorescent host material represented by A-02 in Chemical Formula 4, Alq3 It formed into a film in order of (350 Pa), LiF (5 Pa), and Al (1000 Pa).

1200 cd / m2 (5.7 V) at 0.9 mA, where CIE x = 0.659 and y = 0.327.

Experimental Example 3

The light emitting area of the indium tin oxide (ITO) layer on the substrate was patterned to have a size of 3 mm x 3 mm and then washed. The ITO layer CuPC (650 kPa), NPD (400 kPa), a light emitting layer (200 kPa) containing 5% dopant represented by RD-1 in Chemical Formula 1-4 to the red phosphorescent host material represented by A-08 in Chemical Formula 4, Alq3 It formed into a film in order of (350 Pa), LiF (5 Pa), and Al (1000 Pa).

1240 cd / m2 (5.8 V) at 0.9 mA, where CIE x = 0.658 and y = 0.329.

Experimental Example 4

The light emitting area of the indium tin oxide (ITO) layer on the substrate was patterned to have a size of 3 mm x 3 mm and then washed. ITO layer CuPC (650 kPa), NPD (400 kPa), light emitting layer (200 kPa) containing 5% dopant represented by RD-1 in Chemical Formula 1-4 to red phosphorescent host material represented by A-11 in Chemical Formula 4, Alq3 It formed into a film in order of (350 Pa), LiF (5 Pa), and Al (1000 Pa).

1280cd / m2 (5.6V) at 0.9mA, where CIE x = 0.659 and y = 0.330.

Experimental Example 5

The light emitting area of the indium tin oxide (ITO) layer on the substrate was patterned to have a size of 3 mm x 3 mm and then washed. The ITO layer PEDOT: PSS (800 kPa, spin coating: 3000 rpm, baking condition: 120 ° C., for 1 hr), the red phosphorescent host material represented by A-11 in Formula 4 is represented by RD-1 in Formula 1-4. After spin-coating with a light emitting layer (250 Pa, 3000 rpm, baking condition: 100 ° C. for 30 min) to which 2% of the dopant was added, films were formed in the order of Alq 3 (350 Pa), LiF (5 Pa), and Al (1000 Pa).

1000 cd / m2 (6.5 V) at 0.9 mA, where CIE x = 0.658 and y = 0.331.

Comparative Example 1

The light emitting area of the indium tin oxide (ITO) layer on the substrate was patterned to have a size of 3 mm x 3 mm and then washed. ITO layer CuPC (650 kPa), NPD (400 kPa), Light emitting layer (200 kPa), Alq3 (350 kPa), LiF added 5% of the dopant represented by RD-1 to Chemical Formula 1-4 to CBP represented by Chemical Formula 1-3. (5 microseconds) and Al (1000 microseconds) in order.

790 cd / m2 (7.3 V) at 0.9 mA, where CIE x = 0.659 and y = 0.330.

The comparative results of the above Experimental Examples 1 to 5 and Comparative Example are shown in Table 1 below. The unit of voltage is V, the unit of current is mA, the unit of brightness is cd / m2, the unit of current efficiency is cd / A, the unit of power efficiency is lm / W, and the unit of internal quantum efficiency is%.

Voltage electric current Luminance Current efficiency Power efficiency Internal Quantum Efficiency CIE (X) CIE (Y) Example 1 5.8 0.9 1150 11.5 6.2 15.9 0.658 0.327 Example 2 5.7 0.9 1200 12.0 6.6 16.7 0.659 0.327 Example 3 5.8 0.9 1240 12.4 6.7 17.3 0.658 0.329 Example 4 5.6 0.9 1280 12.8 7.2 17.7 0.659 0.330 Example 5 6.5 0.9 1000 10.0 4.3 14.6 0.658 0.331 Comparative Example 1 7.3 0.9 790 7.9 3.8 10.5 0.659 0.330

As can be seen from Table 1, Experimental Examples 1 to 5 have a high color purity (CIE (X)> 0.65), and at the same time the internal quantum efficiency value is high, the current luminous efficiency is improved. In addition, power consumption is reduced because light of high luminance is emitted at a low driving voltage.

In particular, Experimental Example 5 is a light emitting layer formed by the coating method in the liquid phase, and has an excellent effect on the driving voltage, brightness and the like. Therefore, the red phosphorescent host material according to the first exemplary embodiment of the present invention can manufacture a large area device by a coating method.

Second embodiment

In the red phosphorescent host material according to the second exemplary embodiment of the present invention, a benzo group is positioned at positions 3 and 4, and a substance selected from an aromatic group, a heterocyclic group, an aliphatic group, or hydrogen is substituted at position 6 and is positioned at position 9 Carbazol in which a phenyl group is substituted is symmetrically substituted with biphenyl, and is characterized by having soluble properties, and is represented by the following Chemical Formula 5. The nitrogen of the carbazole is substituted at the metha position of the phenyl group.

Formula 5

In Formula 5, A is selected from a substituted or unsubstituted aromatic group material, a substituted or unsubstituted heterocyclic group material, a substituted or unsubstituted aromatic group material, or hydrogen.

For example, the aromatic group material includes phenyl, naphthyl, biphenyl, terphenyl, and phenanthrenyl.

In addition, the heterocyclic group material is pyridinyl, bipyridinyl, quinolinyl, isoquinolinyl, quinoxalinyl, terpyridinyl, terpyridinyl, phenanthrol It is characterized by the inclusion of phenanthrolinyl.

In addition, the aliphatic group material is characterized by containing C1 ~ C20 aryl, C1 ~ C20 alkyl.

In addition, the substituents of each of the aromatic group material, the heterocyclic group material and the aromatic group material may be C1 to C20 aryl, C1 to C20 alkyl, C1 to C20 alkoxy, halogen ( It is characterized by being selected from halogen, cyano and silyl. For example, the substituent is methyl, ethyl, propyl, isopropyl, butyl (t-butyl), methoxy, ethoxy, butoxy ( butoxy), trimethylsilyl, fluorine, and chlorine.

That is, in the red phosphorescent host material of the second embodiment, a benzo group is positioned at positions 3 and 4, and a substance selected from an aromatic group, a heterocyclic group, an aliphatic group, or hydrogen is substituted at position 6 and phenyl is positioned at position 9 Carbazol substituted with a (phenyl) group is symmetrically substituted with biphenyl, and nitrogen of the carbazole is substituted at the metha position of the phenyl group, thereby having a soluble property.

For example, in Formula 5, A may be selected from a plurality of substance groups represented by Formula 6 below.

Formula 6

According to the selection of A, the red phosphorescent host material of Formula 5 may be any one of a plurality of materials represented by the following Formula 7. Here, for the convenience of explanation, the symbols B01 to B38 are attached to the bottom of each material.

Formula 7

Hereinafter, among the red phosphorescent host materials for organic electroluminescent devices according to the second embodiment of the present invention, the red phosphorescent host materials represented by B-01 and B-02 in Chemical Formula 7 will be exemplified. Explain 4.

Third Synthetic example

1.Synthesis of 2,2'-biphenyldiboronic acid

2,2'-biphenyldiboronic acid is synthesized by Reaction 7

Scheme 7

Specifically, 2,2'-dibromobiphenyl (10 g, 0.03 mol) and 100 mL of ether are added to a two-necked round flask and stirred. After the temperature was lowered to -78 ° C by a dry-ice bath, 2.5M n-BuLi (26.9mL, 0.067mol) was slowly dropped and stirred at room temperature for 1 hour. Lower the temperature to -78 ℃ again with a dry-ice bath, slowly drop triethylborate (19.5g, 0.13mol) and stir again at room temperature for 4 hours. 100 mL of 2N HCl was added to terminate the reaction, and the solvent was evaporated. The resulting solid was filtered and washed 3-4 times with distilled water and hexane to give 2,2'-biphenyldiboronic acid (5.4g, yield: 70%).

2. Synthesis of 2,2'-bis (3'-bromophenyl) biphenyl

2,2'-bis (3'-bromophenyl) biphenyl is synthesized by the following scheme 8.

Scheme 8

Specifically, 2,2'-biphenyldiboronic acid (5g, 0.02mol), 1-bromo-3-iodobenzene (12.9g, 0.045mol), Pd (PPh3) 4 (0.1g, 0.9mmol), K2CO3 and 90 mL of toluene / EtOH (3: 1) were added and refluxed for 12 hours. After cooling to room temperature, extracted with methylene chloride, the solvent was evaporated, purified by silica gel column (2,2'-bis (3'-bromophenyl) biphenyl (7.8g, yield: 80%) Got.

3. Synthesis of B-01

The red phosphorescent host material represented by B-01 in Chemical Formula 7 is synthesized by the following Scheme 9.

Scheme 9

Specifically, 2,2'-bis (3'-bromophenyl) biphenyl (1g, 2.1mmol), benzo [3,4] carbazole (1g, 4.7mmol), Pd2 (dba) 3, P ( t-Bu) 3, NaOBu (0.6 g, 6 mmol) and toluene were added and refluxed at 130 ° C. for 18 hours. After cooling to room temperature, the mixture was extracted with methylene chloride, the solvent was evaporated, and purified by silica gel column to obtain B-01 (1.1 g, yield: 70%).

Fourth Synthetic example

1.Synthesis of 2,2'-biphenyldiboronic acid

2,2'-biphenyldiboronic acid is synthesized by Reaction 10 below.

Scheme 10

Specifically, 2,2'-dibromobiphenyl (10 g, 0.03 mol) and 100 mL of ether are added to a two-necked round flask and stirred. After the temperature was lowered to -78 ° C by a dry-ice bath, 2.5M n-BuLi (26.9mL, 0.067mol) was slowly dropped and stirred at room temperature for 1 hour. Lower the temperature to -78 ℃ again with a dry-ice bath, slowly drop triethylborate (19.5g, 0.13mol) and stir again at room temperature for 4 hours. 100 mL of 2N HCl was added to terminate the reaction, and the solvent was evaporated. The resulting solid was filtered and washed 3-4 times with distilled water and hexane to give 2,2'-biphenyldiboronic acid (5.4g, yield: 70%).

2. Synthesis of 2,2'-bis (3'-bromophenyl) biphenyl

2,2'-bis (3'-bromophenyl) biphenyl is synthesized by the following Scheme 11.

Scheme 11

Specifically, 2,2'-biphenyldiboronic acid (5g, 0.02mol), 1-bromo-3-iodobenzene (12.9g, 0.045mol), Pd (PPh3) 4 (0.1g, 0.9mmol), K2CO3 and 90 mL of toluene / EtOH (3: 1) were added and refluxed for 12 hours. After cooling to room temperature, extracted with methylene chloride, the solvent was evaporated, purified by silica gel column (2,2'-bis (3'-bromophenyl) biphenyl (7.8g, yield: 80%) Got.

3. Synthesis of B-02

The red phosphorescent host material represented by B-02 in Chemical Formula 7 is synthesized by the following Scheme 12.

Scheme 12

Specifically, 2,2'-bis (3'-bromophenyl) biphenyl (1g, 2.1mmol), 3-phenylbenzo [3,4] carbazole (1g, 4.7mmol), Pd2 (dba) 3, P (t-Bu) 3, NaOBu (0.6 g, 6 mmol) and toluene were added and refluxed at 130 ° C. for 18 hours. After cooling to room temperature, the mixture was extracted with methylene chloride, the solvent was evaporated, and purified by silica gel column to obtain B-02 (1.1 g, yield: 70%).

Hereinafter, the red phosphorescent host material according to the present invention and the organic field using the same through Experimental Examples 6 to 10, which fabricate an organic light emitting display device using the red phosphorescent host material according to the second embodiment of the present invention. The performance of a light emitting element is compared and demonstrated.

Experimental Example 6

The light emitting area of the indium tin oxide (ITO) layer on the substrate was patterned to have a size of 3 mm x 3 mm and then washed. The ITO layer CuPC (650 kPa), NPD (400 kPa), a light emitting layer (200 kPa) containing 5% of a dopant represented by RD-1 in Chemical Formula 1-4 to the red phosphorescent host material represented by B-01 in Chemical Formula 7, Alq3 It formed into a film in order of (350 Pa), LiF (5 Pa), and Al (1000 Pa).

1200 cd / m2 (5.7 V) at 0.9 mA, where CIE x = 0.658 and y = 0.326.

Experimental Example 7

The light emitting area of the indium tin oxide (ITO) layer on the substrate was patterned to have a size of 3 mm x 3 mm and then washed. ITO layer CuPC (650 kPa), NPD (400 kPa), light emitting layer (200 kPa) containing 5% dopant represented by RD-1 in Chemical Formula 1-4 to red phosphorescent host material represented by B-02 in Chemical Formula 7, Alq3 It formed into a film in order of (350 Pa), LiF (5 Pa), and Al (1000 Pa).

1250 cd / m2 (5.7 V) at 0.9 mA, where CIE x = 0.658 and y = 0.326.

Experimental Example 8

The light emitting area of the indium tin oxide (ITO) layer on the substrate was patterned to have a size of 3 mm x 3 mm and then washed. The ITO layer CuPC (650 kPa), NPD (400 kPa), a light emitting layer (200 kPa) containing 5% of a dopant represented by RD-1 in Chemical Formula 1-4 to the red phosphorescent host material represented by B-08 in Chemical Formula 7, Alq3 It formed into a film in order of (350 Pa), LiF (5 Pa), and Al (1000 Pa).

At 0.9 mA, 1290 cd / m2 (5.6 V) was shown, with CIE x = 0.658 and y = 0.330.

Experimental Example 9

The light emitting area of the indium tin oxide (ITO) layer on the substrate was patterned to have a size of 3 mm x 3 mm and then washed. The ITO layer CuPC (650 kPa), NPD (400 kPa), a light emitting layer (200 kPa) containing 5% of a dopant represented by RD-1 in Chemical Formula 1-4 to the red phosphorescent host material represented by B-11 in Chemical Formula 7, Alq3 It formed into a film in order of (350 Pa), LiF (5 Pa), and Al (1000 Pa).

1310 cd / m2 (5.6 V) at 0.9 mA, where CIE x = 0.657 and y = 0.330.

Experimental Example 10

The light emitting area of the indium tin oxide (ITO) layer on the substrate was patterned to have a size of 3 mm x 3 mm and then washed. The ITO layer PEDOT: PSS (800 kPa, spin coating: 3000 rpm, baking condition: 120 ° C., for 1 hr), the red phosphorescent host material represented by B-11 in Formula 7 is represented by RD-1 in Formula 1-4. After spin-coating with a light emitting layer (250 Pa, 3000 rpm, baking condition: 100 ° C. for 30 min) to which 2% of the dopant was added, films were formed in the order of Alq 3 (350 Pa), LiF (5 Pa), and Al (1000 Pa).

At 0.9mA, 1060cd / m2 (6.5V) was shown, with CIE x = 0.657 and y = 0.330.

Comparative Example 2

The light emitting area of the indium tin oxide (ITO) layer on the substrate was patterned to have a size of 3 mm x 3 mm and then washed. ITO layer CuPC (650 kPa), NPD (400 kPa), Light emitting layer (200 kPa), Alq3 (350 kPa), LiF added 5% of the dopant represented by RD-1 to Chemical Formula 1-4 to CBP represented by Chemical Formula 1-3. (5 microseconds) and Al (1000 microseconds) in order.

At 0.9mA, 780cd / m2 (7.5V) was shown, with CIE x = 0.659 and y = 0.329.

The comparison results of the above Experimental Examples 6 to 10 and Comparative Example 2 are shown in Table 2 below. The unit of voltage is V, the unit of current is mA, the unit of brightness is cd / m2, the unit of current efficiency is cd / A, the unit of power efficiency is lm / W, and the unit of internal quantum efficiency is%.

Voltage electric current Luminance Current efficiency Power efficiency Internal Quantum Efficiency CIE (X) CIE (Y) Example 1 5.7 0.9 1200 12.0 6.6 17.0 0.658 0.326 Example 2 5.7 0.9 1250 12.5 6.9 17.3 0.658 0.326 Example 3 5.6 0.9 1290 12.9 7.2 17.5 0.658 0.330 Example 4 5.6 0.9 1310 13.1 7.3 17.7 0.657 0.330 Example 5 6.5 0.9 1060 10.6 5.1 15.5 0.657 0.330 Comparative Example 1 7.5 0.9 780 7.8 3.3 10.4 0.659 0.329

As can be seen from Table 2, Experimental Examples 6 to 10 have a high color purity (CIE (X)> 0.65), and at the same time the internal quantum efficiency value is high, the current luminous efficiency is improved. In addition, power consumption is reduced because light of high luminance is emitted at a low driving voltage.

In particular, Experimental Example 10 is to form a light emitting layer by the coating method in the liquid phase, and has an excellent effect on the driving voltage, brightness and the like. Accordingly, the red phosphorescent host material according to the second exemplary embodiment of the present invention can manufacture a large area device by a coating method.

An embodiment of an organic light emitting display device including the red phosphorescent host material is illustrated in FIG. 2.

As illustrated, the organic light emitting diode includes first and second substrates (not shown) facing each other and an organic light emitting diode (E) formed between the first and second substrates (not shown). .

The organic light emitting diode E is an organic light emitting layer 120 formed between the first electrode 110 serving as an anode, the second electrode 130 serving as a cathode, and the first and second electrodes 110 and 130. )

The first electrode 110 is formed of a material having a relatively high work function, for example, indium tin oxide (ITO), and the second electrode 130 is formed of a material having a relatively low work function, for example. For example, it is made of aluminum (Al) or aluminum alloy (AlNd). In addition, the organic light emitting layer 120 includes red, green, and blue organic light emitting patterns.

The organic light emitting layer 120 has a multi-layer structure, that is, a hole injection layer (HTL) 121, a hole transporting layer (HIL) in order to maximize the luminous efficiency sequentially from the first electrode 110 ) 122, an emitting material layer (EML) 123, an electron transporting layer 124, and an electron injection layer 125.

Here, the light emitting material layer 123 includes a red phosphorescent host material represented by Formula 2 or 5 above. The red phosphorescent host material is dissolved in a solvent such as xylene at about 1 to 10 wt%, and about 1 to 10 wt% of a dopant is added to prepare a light emitting material layer solution. The light emitting material layer solution is coated to form the light emitting material layer 123. In particular, the red phosphorescent host material of the present invention has excellent solubility in non-polar solvents. If the coating process is performed using a polar solvent, when the solvent is evaporated by using a hot plate or the like, the solvent remains and may act as a bond. However, this problem does not occur when using a nonpolar solvent. The light emitting material layer 123 may further include green and blue light emitting material layers.

The organic light emitting diode having such a structure has an advantage in manufacturing a large area organic light emitting diode because the light emitting material layer 123 is formed by coating a light emitting material layer solution. In addition, it is possible to realize a high-brightness image, and also to improve the luminous efficiency to enable a low power drive has the advantage of reducing the power consumption.

Although the above has been described with reference to a preferred embodiment of the present invention, those skilled in the art various modifications and changes of the present invention without departing from the spirit and scope of the present invention described in the claims below I can understand that you can.

110: first electrode
120: organic light emitting layer
123: light emitting material layer
130: second electrode

Claims (7)

It is represented by the following formula (1) or (2), A is an organic electric field characterized in that selected from substituted or unsubstituted aromatic group material, substituted or unsubstituted heterocyclic group material, substituted or unsubstituted aromatic group material, or hydrogen Red phosphorescent host material for light emitting devices.
Formula 1

Formula 2

The method of claim 1,
The aromatic group material is a red phosphorescent host material, characterized in that it includes phenyl, naphthyl, biphenyl, terphenyl, phenanthrenyl.
The method of claim 1,
The heterocyclic group material may be pyridinyl, bipyridinyl, quinolinyl, isoquinolinyl, quinoxalinyl, terpyridinyl, phenoxrollinyl ( red phosphorescent host material characterized by containing phenanthrolinyl).
The method of claim 1,
The aliphatic group material is C1 to C20 aryl (aryl), C1 to C20 alkyl (red) characterized in that it comprises a red phosphorescent host material.
The method of claim 1,
Substituents of each of the aromatic group material, the heterocyclic group material and the aromatic group material are C1 ~ C20 aryl, C1 ~ C20 alkyl, C1 ~ C20 alkoxy, halogen , Red phosphorescent host material, characterized in that selected from cyano, silyl.
A first electrode;
A second electrode facing the first electrode;
A light emitting material layer positioned between the first and second electrodes,
The light emitting material layer is represented by Formula 1 or Formula 2, A is selected from a substituted or unsubstituted aromatic group material, a substituted or unsubstituted heterocyclic group material, a substituted or unsubstituted aromatic group material, or hydrogen An organic light emitting display device comprising: a red phosphorescent host material.
Formula 1

Formula 2

The method according to claim 6,
The red phosphorescent host material is soluble in a nonpolar solvent, characterized in that formed by a coating process organic light emitting device.

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