WO2018105775A1 - Indazole compound and organic light emitting device comprising same - Google Patents

Abstract

The present invention relates to an indazole compound and an organic light emitting device which exhibits superior efficiency characteristics by comprising the indazole compound in one or more organic layers.

Description

Indazole compound and organic light emitting device comprising the same

The present invention relates to an indazole compound and an organic light emitting device comprising the same.

The organic light emitting device is a device for converting electrical energy into light energy using an organic material, and includes a structure in which a light emitting organic material layer is formed between an anode and a cathode.

The organic light emitting device may be formed in various structures, among which a tandem organic light emitting device in which a plurality of light emitting parts are stacked is studied.

In a tandem organic light emitting device, a plurality of light emitting parts including a light emitting layer are stacked between an anode and a cathode. A charge generation layer for generating and moving charges is positioned between adjacent light emitting units.

The charge generation layer requires low driving voltage and high efficiency.

It is an object of the present invention to provide indazole compounds of novel structure.

Another object of the present invention is to minimize the energy level difference between the n-type charge generation layer and the p-type charge generation layer in the tandem organic light emitting device to improve the amount of electron injection in the light emitting portion and the organic light emitting comprising the same It is to provide an element.

Still another object of the present invention is to provide an indazole compound capable of minimizing the diffusion of alkali metal into the p-type charge generation layer even when the n-type charge generation layer is doped with an alkali metal, and an organic light emitting device including the same. It is.

The object of the present invention is achieved by an indazole compound represented by the following formula (1).

[Formula 1]

In Formula 1, R ₁ and R ₂ are hydrogen or unsubstituted or unsubstituted 5 to 60 containing one or more heteroatoms selected from aryl groups having 3 to 60 carbon atoms, nitrogen, oxygen and sulfur. A membered heteroaryl group, an arylamine group, or a secondary amine group, X ₁ and X ₂ are selected from nitrogen or carbon, and at least one of X ₁ and X ₂ is nitrogen.

The indazole compound may be represented by the following formula (2).

[Formula 2]

X ₃ may be selected from nitrogen or carbon.

R ₁ and R ₂ are each independently hydrogen, substituted or unsubstituted phenyl, alkylphenyl, biphenyl, alkylbiphenyl, halophenyl, alkoxyphenyl, haloalkoxyphenyl, cyanophenyl, silylphenyl, naphthyl, alkyl Naphthyl, halonaphthyl, cyanonaphthyl, silylnaphthyl, pyridyl, alkylpyridyl, halopyridyl, cyanopyridyl, alkoxypyridyl, silylpyridyl, pyrimidyl, halopyrimidyl, cyanopyri Midyl, alkoxypyrimidyl, quinolinyl, isoquinolinyl, quinoxalinyl, pyrazinyl, quinazolinyl, naphthyridinyl, benzothiophenyl, benzofuranyl, dibenzothiophenyl, arylthiazolyl, dibenzofu May be selected from ranyl, fluorenyl, carbazoyl, imidazolyl, carbolinyl, phenanthrenyl, terphenyl, terpyridinyl, triphenylenyl, fluoroantenyl and diacafluorenyl.

The object of the present invention is a first electrode; Second electrode; And an organic material layer disposed between the first electrode and the second electrode and emitting light, wherein the organic material layer is formed of a plurality of layers, and at least one layer is achieved by an organic light emitting device including the indazole compound. do.

The at least one layer may include a charge generation layer (CGL).

The charge generation layer CGL may be n-type.

The at least one layer may include an electron transport layer.

The object of the present invention is a first electrode; Second electrode; And a first light emitting part disposed between the first electrode and the second electrode and including a first light emitting layer. A second light emitting part disposed between the second electrode and the first light emitting part and including a second light emitting layer; And a charge generating layer positioned between the first light emitting portion and the second light emitting portion, wherein the charge generating layer is achieved by an organic light emitting device including the indazole compound.

According to the present invention, an indazole compound of a novel structure is provided.

According to the present invention, an indazole compound capable of improving the driving voltage and efficiency by improving the electron injection amount in the light emitting part by minimizing the energy level difference between the n-type charge generation layer and the p-type charge generation layer and an organic light emitting device comprising the same Is provided.

According to the present invention, even when the n-type charge generation layer is doped with an alkali metal, the alkali metal is tightly coordinated with an indazole compound which is a host material to minimize diffusion of the alkali metal into the p-type charge generation layer. Provided are an indazole compound capable of improving lifespan and an organic light emitting device comprising the same.

1 is a cross-sectional view of an organic light emitting diode according to an embodiment of the present invention.

Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail. However, the present invention is not limited to the embodiments disclosed below, but can be implemented in various different forms, only the embodiments are to make the disclosure of the present invention complete, the common knowledge in the art to which the present invention belongs It is provided to fully inform those having the scope of the invention, the scope of the invention is defined only by the claims.

The size and thickness of each component shown in the drawings are shown for convenience of description, and the present invention is not necessarily limited to the size and thickness of the illustrated configuration.

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

The indazole compound according to the present invention is represented by the formula (1) or (2).

[Formula 1]

 [Formula 2]

Formula (I) and R ₁ and R ₂ are hydrogen, a substituted or non-substituted C 3 -C 60 aryl group, to 5 won unsubstituted or substituted, which contain one or more heteroatoms selected from nitrogen, oxygen and sulfur in the general formula (2) A 60-membered heteroaryl group, an arylamine group, or a secondary amine group is represented.

In Formula 1 and Formula 2, X 1, X 2 and X 3 are selected from nitrogen or carbon, and at least one of X 1 and X 2 is nitrogen.

R ₁ and R ₂ are each independently hydrogen, substituted or unsubstituted phenyl, alkylphenyl, biphenyl, alkylbiphenyl, halophenyl, alkoxyphenyl, haloalkoxyphenyl, cyanophenyl, silylphenyl, naphthyl, alkyl Naphthyl, halonaphthyl, cyanonaphthyl, silylnaphthyl, pyridyl, alkylpyridyl, halopyridyl, cyanopyridyl, alkoxypyridyl, silylpyridyl, pyrimidyl, halopyrimidyl, cyanopyri Midyl, alkoxypyrimidyl, quinolinyl, isoquinolinyl, quinoxalinyl, pyrazinyl, quinazolinyl, naphthyridinyl, benzothiophenyl, benzofuranyl, dibenzothiophenyl, arylthiazolyl, dibenzofu May be selected from ranyl, fluorenyl, carbazoyl, imidazolyl, carbolinyl, phenanthrenyl, terphenyl, terpyridinyl, triphenylenyl, fluoroantenyl and diacafluorenyl.

The indazole compound according to the present invention may be a compound shown below.

Compounds represented by the formulas (1) and (2) of the present invention are bound to position 7 of pyridoindazole to position 2 of quinoline and phenanthrosine. This structure is a structure in which three nitrogen atoms are adjacent to each other and are very stable. And nitrogen (N) in sp ² hybrid orbitals, which are relatively rich in electrons. This nitrogen binds to an alkali metal or alkaline earth metal, which is a dopant of the N-type charge generation layer, to form a gap state. By the formed gap state, electrons can be smoothly transferred from the P-type charge generation layer to the N-type charge generation layer.

In addition, various chemical formulas have been made to improve electron injection characteristics of the charge generation layer in the chemical formula of the present invention. Through various synthesis, the host included in the charge generation layer introduced anthracene compound, pyrene compound and other aryl compounds.

1 is a cross-sectional view of an organic light emitting diode according to an embodiment of the present invention. Referring to FIG. 1, the organic light emitting diode 1 has a tandem type structure, and includes a first electrode (anode 110), a second electrode (cathode 120), a first light emitter 210, and a second light emitter 220. And a charge generation layer 230.

The first light emitting unit 210, the second light emitting unit 220, and the charge generation layer 230 are positioned between the first electrode 110 and the second electrode 120 as an organic layer, and the charge generation layer 230 is Located between the first light emitting unit 210 and the second light emitting unit 220.

The first light emitting part 210 includes a hole injection layer 211, a first hole transporting layer 212, a first light emitting layer 213, and a first electron transporting layer 214, and the second light emitting part 220 is formed of a first light emitting part 220. The two hole transport layer 221, the second light emitting layer 222, the second electron transport layer 223 and the electron injection layer 224.

The charge generation layer 230 includes an n-type charge generation layer 231 and a p-type charge generation layer 232. The n-type charge generation layer 231 may be doped with an alkali metal.

The indazole compound according to the present invention may be used in the first electron transport layer 212, the second electron transport layer 223, and the charge generation layer 230, and in particular, may be used in the n-type charge generation layer 231. .

The organic light emitting device 1 described above can be variously modified. Some organic layers may be omitted or added, may not be tandem, or may be tandem having three or more light emitting layers.

Hereinafter, examples of the compound 3 and examples and comparative examples of the organic light emitting diode will be described. However, the production examples and examples described below are merely for illustrating or explaining the present invention in detail, and should not be construed as limiting the present invention by the production examples and examples described below.

Preparation of Compound 2-3

In a 2 L three-necked flask, 30 g (149.98 mmol) of 1- (6-bromopyridin-2-yl) ethanone and 32.5 g (194.97 mmol) of (2-nitrophenyl) boronic acid were charged. 62.2 g (449.93 mmol) of K ₂ CO ₃ and 4.5 g (4.5 mmol) of Pd (PPh ₃ ) ₄ were added thereto, followed by nitrogen replacement in 400 ml of toluene, 200 ml of H ₂ O, and 200 ml of ethanol, followed by reflux for 4 hours. Stirring was performed. After the reaction was completed, the mixture was extracted with MC, the organic layer was dried over MgSO ₄ , and recrystallized with methanol to obtain 28.76 g (79.3%) of the title compound 2-3.

Preparation of Compound 2-2

In a 1 L three-neck flask, 28.8 g (118.9 mmol) of Compound 2-3 and 78 g (297.24 mmol) of triphenylphosphine were dissolved in 300 ml of ortho-dichlorobenzene, followed by stirring under reflux for 15 hours. After the reaction was completed, the solvent was removed by distillation under reduced pressure and purified by column chromatography to obtain 18.99 g (76.73%) of Compound 2-2.

Preparation of Compound 1-38

4.17 g (20.02 mmol) of Compound 2-2 and 4.13 g (24.03 mmol) of 8-aminoquinoline-7-carbaaldehyde were added to a 250 ml three-neck flask. After dissolving in 100 ml of ethanol, 2.25 g (40.05 mmol) of KOH was added thereto, followed by stirring under reflux for 3 hours. When the reaction was completed, 100 ml of H ₂ O was added to precipitate. The precipitated solid was filtered and purified by column chromatography to give 4.38 g (63.18%) of compound 1.

Preparation of Compound 2-a

5 g (24.01 mmol) of Compound 2-2 and 6.6 g (26.41 mmol) of 8-amino-5-bromoquinoline-7-carbaaldehyde were added to a 250 ml three-neck flask. 2.7 g (48.02 mmol) of KOH was dissolved in 100 ml of ethanol and stirred under reflux for 3 hours. When the reaction was completed, 100 ml of H ₂ O was added to precipitate. The precipitated solid was filtered and purified by column chromatography to give 6.38 g (62.5%) of compound 2-a.

Manufacture compound 1-69

6.38 g (15.00 mmol), 5- (4- (4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl) phenyl) pyrimidine in a 250 ml three necked flask 19.50 mmol) was added. 6.2 g (45.01 mmol) of K ₂ CO ₃ and 0.52 g (0.45 mmol) of Pd (PPh ₃ ) ₄ were added thereto, followed by stirring under reflux for 21 hours in a mixed solution of 50 ml of toluene, 30 ml of H ₂ O, and 30 ml of ethanol. When the reaction is completed, 100 ml of methanol is added to precipitate. The precipitated solid is filtered and washed three times with 50 ml of H ₂ O. The dried solid was purified by column chromatography to give 6.5g (86.6%) of compound 1-69.

Compound 1-64 Preparation

6.38 g (15.00 mmol) of Compound 2-a and 3.86 g (19.50 mmol) of [1,1'-biphenyl] -4-ylboronic acid were added to a 250 ml three-neck flask. 6.2 g (45.01 mmol) of K ₂ CO ₃ and 0.52 g (0.45 mmol) of Pd (PPh ₃ ) ₄ were added thereto, followed by stirring under reflux for 21 hours in a mixed solution of 50 ml of toluene, 30 ml of H ₂ O, and 30 ml of ethanol. When the reaction was completed, 100 ml of methanol was added to precipitate. The precipitated solid is filtered and washed three times with 50 ml of H2O. The dried solid was purified by column chromatography to give 3.38 g (57.65%) of Compound 1-64.

Preparation of Compound 2-b

5 g (24.01 mmol) of Compound 2-2 and 5.3 g (26.41 mmol) of 2-amino-4-bromobenzaldehyde were added to a 250 ml three-neck flask. 2.7 g (48.02 mmol) of KOH was dissolved in 100 ml of ethanol and stirred under reflux for 3 hours. When the reaction is completed, 100 ml of H ₂ O is added to precipitate. The precipitated solid was filtered and purified by column chromatography to give 6.6 g (73.46%) of compound 2-b.

Preparation of Compound 1-24

In a 250 ml three-necked flask, 6.6 g (17.64 mmol) of Compound 2-b and 6.83 g (22.93 mmol) of (10-phenylanthracene-9-yl) boronic acid were added thereto. 7.3 g (52.91 mmol) of K ₂ CO ₃ and 0.62 g (0.53 mmol) of Pd (PPh ₃ ) ₄ were added thereto, followed by stirring under reflux for 4 hours in a mixed solution of 50 ml of toluene, 30 ml of H ₂ O, and 20 ml of ethanol. After the reaction was completed, 100 ml of H ₂ O was added, extracted with MC, and the organic layer was dried over MgSO ₄ . Purified by column chromatography to give 4.85g (87.93%) of compound 1-24.

Each compound was identified through NMR and GC-MS.

NMR: Nuclear Magnetic Resonance 500 (Nuclear Magnetic Resonance Spectrometer 500 MHz)

Model Name: Avance-500 (Bruker)

GC-MS: Gas Chromatography-Mass Spectrometer Model: JMS-700, 6890 Series

[Production of Organic EL Device]

Comparative example

After patterning the ITO board | substrate so that a light emitting area might be set to 2 mm x 2 mm, it wash | cleaned with isopropyl alcohol and UV ozone, respectively. Thereafter, the ITO substrate was mounted on the substrate holder of the vacuum deposition apparatus and pressure was applied such that the vacuum degree was 1 × 10 ⁻⁷ torr.

First, a HAT-CN compound was vacuum deposited to form a 5 nm thick. This compound acts as a hole transport layer. An NPB material was formed to a thickness of 35 nm as a hole transport layer thereon.

Thereafter, a CBP material was used as a host, and an Ir compound was co-deposited at a thickness of 30 nm to form a dopant of about 10% by mass to form a yellow light emitting layer.

The first electron transport layer was formed on the light emitting layer with a TmPyPB compound having a thickness of 25 nm. Subsequently, a second electron transport layer was formed by co-depositing a Li material on the BPhen material to a thickness of 10 nm to have a 2% mass ratio. Thereafter, Al was deposited to a thickness of 100 nm to form a cathode to fabricate an organic EL device.

Example 1

The organic light emitting device was manufactured by the same method as the comparative example described above, but replacing only the second electron transport material with 1-69 compound.

Example 2

The organic light emitting device was fabricated in the same manner as the comparative example described above, but replacing only the second electron transport material with a 1-24 compound.

Example 3

The organic light emitting device was manufactured by the same method as the comparative example described above, but replacing only the second electron transport material with a 1-38 compound.

Example 4

The organic light emitting device was fabricated in the same manner as the comparative example described above, except that only the second electron transport material was converted into a 1-64 compound.

In the case of PIN OLEDs, low-voltage high-efficiency driving is realized through electrical doping of the charge transport layer in the OLED structure. The P doping layer is doped with an electron-lean organic material or metal oxide in the hole transport material, and the N doping layer is doped with an alkali metal such as lithium or cesium having a low work function in the electron transport material. The doped layer reduces the surface resistance of the organic material during operation to facilitate charge injection from adjacent layers. The introduction of a buffer layer on the doped anode layer realizes low voltage by energy banding and a low voltage driving technique using a material having high charge mobility, and has obtained high efficiency by manufacturing a fluorescent and phosphorescent material in a laminated structure.

Tandem structure is a structure in which the EL units including the doped hole transport layer and the electron transport layer are vertically stacked, and the current luminous efficiency increases in proportion to the number of stacked layers. In this case, the CGL (change generation layer) layer is a concept of a transparent PN junction, and can be understood as a concept in which a unit PIN OLED light emitting unit is stacked in a plurality of layers. Therefore, even a single layer PIN OLED embodiment can predict the efficiency and voltage of the stack structure.

The current density, driving voltage, current efficiency, and external quantum efficiency of the organic light emitting diodes of Examples and Comparative Examples were measured, and the results are shown in Table 1 below.

	matter	Driving strategy (mA / cm 2 )	Driving voltage (V)	Current efficiency (cd / A)	Quantum Efficiency (%)
Comparative example	Bphen	10	4.5	56.5	19.1
Example 1	1-69	10	4.1	62.7	21.2
Example 2	1-24	10	4.1	59.8	20.4
Example 3	1-38	10	4.0	63.2	21.0
Example 4	1-64	10	4.1	59.0	20.0

It can be seen that the driving voltage of the embodiment is lower than that of the comparative example while the current efficiency and the quantum efficiency of the example are higher than the comparative example.

The present invention is not necessarily limited to these embodiments, and various modifications can be made without departing from the spirit of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention but to describe the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive. The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of the present invention.

Claims (9)

1. Indazole compound represented by the following formula (1).

   [Formula 1]

   In Chemical Formula 1,

   R ₁ and R ₂ are hydrogen or a substituted or unsubstituted 5- to 60-membered heteroaryl group including one or more heteroatoms selected from aryl groups having 3 to 60 carbon atoms, nitrogen, oxygen and sulfur, An arylamine group or a secondary amine group,

   X ₁ and X ₂ are selected from nitrogen or carbon, and at least one of X ₁ and X ₂ is nitrogen.
2. The method of claim 1,

   Indazole compound, characterized in that represented by the formula (2).

   [Formula 2]

   

   X ₃ is selected from nitrogen or carbon.
3. The method according to any one of claims 1 and 2,

   R ₁ and R ₂ are each independently hydrogen, substituted or unsubstituted phenyl, alkylphenyl, biphenyl, alkylbiphenyl, halophenyl, alkoxyphenyl, haloalkoxyphenyl, cyanophenyl, silylphenyl, naphthyl, alkyl Naphthyl, halonaphthyl, cyanonaphthyl, silylnaphthyl, pyridyl, alkylpyridyl, halopyridyl, cyanopyridyl, alkoxypyridyl, silylpyridyl, pyrimidyl, halopyrimidyl, cyanopyri Midyl, alkoxypyrimidyl, quinolinyl, isoquinolinyl, quinoxalinyl, pyrazinyl, quinazolinyl, naphthyridinyl, benzothiophenyl, benzofuranyl, dibenzothiophenyl, arylthiazolyl, dibenzofu Indazole compound, characterized in that it is selected from ranyl, fluorenyl, carbazoyl, imidazolyl, carbolinyl, phenanthrenyl, terphenyl, terpyridinyl, triphenylenyl, fluoroantenyl and diacafluorenyl .
4. The method of claim 1,

   Indazole compound, characterized in that any one of the compounds shown below.

   

   

   

   

   

   
5. A first electrode;

   Second electrode; And

   An organic material layer disposed between the first electrode and the second electrode and emitting light;

   The organic layer is composed of a plurality of layers and at least one layer of the organic light emitting device comprising the indazole compound according to any one of claims 1 to 4.
6. The method of claim 5,

   The at least one layer is characterized in that it comprises a charge generation layer (Charge Generation Layer; CGL), the organic light emitting device.
7. The method of claim 6,

   The charge generation layer (CGL) is an organic light emitting device, characterized in that the n-type.
8. The method of claim 5,

   The at least one layer is an organic light emitting device comprising an electron transport layer.
9. A first electrode;

   Second electrode; And

   A first light emitting part disposed between the first electrode and the second electrode and including a first light emitting layer;

   A second light emitting part disposed between the second electrode and the first light emitting part and including a second light emitting layer;

   A charge generation layer positioned between the first light emitting unit and the second light emitting unit,

   The charge generating layer is an organic light emitting device comprising the indazole compound according to any one of claims 1 to 4.

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