KR20220057891A - A green phosphorescent host compound comprising phosphine and organic electroluminescent device using the same - Google Patents

Abstract

The present invention relates to a green phosphorescent host compound, a composition for a green phosphorescent host, and an organic electroluminescent device comprising the same in a light emitting layer, and more specifically, to a green phosphorescent host compound which can improve the light emitting efficiency, lifetime and color purity of a device by including a single compound or a plurality of compounds in a light emitting layer, have excellent thermal denaturation properties due to a low deposition temperature, and lower driving voltage, an organic electroluminescent device comprising the same in a light emitting layer.

Description

A green phosphorescent host compound comprising phosphine and organic electroluminescent device using the same

The present invention relates to a green phosphorescent host compound, a composition for a green phosphorescent host, and an organic electroluminescent device comprising the same in a light emitting layer, and more particularly, by including a single compound or a plurality of compounds in the light emitting layer, luminous efficiency, lifespan and color purity of the device It relates to a green phosphorescent host compound capable of improving and lowering the deposition temperature, thereby having excellent thermal denaturation characteristics, and lowering a driving voltage, and an organic electroluminescent device including the same in a light emitting layer.

The flat panel display plays a very important role in supporting the advanced image information society centering on the Internet, which is showing rapid growth in recent years. In particular, organic light emitting diodes (OLEDs), which are self-luminous and capable of low voltage driving, have superior viewing angles and contrast ratio compared to liquid crystal displays (LCDs), which are the main types of flat panel display devices, and are lightweight and thin because they do not require a backlight. possible, and has an advantageous advantage in terms of power consumption. In addition, it is attracting attention as a next-generation display device because of its fast response speed and wide color reproduction range.

In general, an organic light emitting diode is formed on a glass substrate in order of an anode made of a transparent electrode, an organic thin film including a light emitting region, and a metal electrode (cathode). In this case, the organic thin film includes an emitting layer (EML), a hole injection layer (HIL), a hole transport layer (HTL), an electron transport layer (ETL), and an electron injection layer (electron injection). layer, EIL), and may further include an electron blocking layer (EBL) or a hole blocking layer (HBL) due to the light emitting characteristics of the light emitting layer.

When an electric field is applied to the organic light emitting diode having this structure, holes are injected from the anode and electrons are injected from the cathode, and the injected holes and electrons pass through the hole transport layer and electron transport layer, respectively, and recombine in the light emitting layer to form a light emitting exciton. The light emitting exciton emits light while transitioning to the ground state. At this time, a light emitting dye (guest) is doped into the light emitting layer (host) to increase the efficiency and stability of the light emitting state.

The main issues of organic light emitting diodes are luminous efficiency, lifespan, and stability. In order to improve these characteristics, various derivatives have been developed and used as light emitting materials.

However, the conventional compounds cannot be used stably for a long period of time in organic light emitting diodes, organic light emitting diodes, etc. due to low luminous efficiency, lifespan, color purity and stability.

Therefore, it is necessary to develop a technology for a green phosphorescent host compound and composition capable of improving the luminous efficiency, lifespan, color purity and stability of the device and lowering the driving voltage.

Korea Patent Publication No. 10-2011-0046839 (May 06, 2011)

The present invention has been devised to solve the above problems, and by including a single compound or a plurality of compounds in the light emitting layer, the luminous efficiency, lifespan and color purity of the device are improved, and the thermal denaturation property is excellent by having a low deposition temperature, and the driving voltage is lowered. An object of the present invention is to provide a green phosphorescent host compound capable of being able to and an organic electroluminescent device including the same in a light emitting layer.

The present invention provides a green phosphorescent host compound having a structure of Formula 1, Formula 2, or Formula 3 below.

[Formula 1]

(R ₁ and R ₂ are independently substituted or unsubstituted C6~ C50 aryl, or substituted or unsubstituted heteroaryl having 3 to 50 nuclear atoms.)

[Formula 2]

(R ₃ and R ₄ are independently substituted or unsubstituted C6~ C50 aryl, or substituted or unsubstituted heteroaryl having 3 to 50 nuclear atoms.)

[Formula 3]

(R ₅ and R ₆ are independently substituted or unsubstituted C6~ C50 aryl, or substituted or unsubstituted heteroaryl having 3 to 50 nuclear atoms.)

In one embodiment of the present invention, the compound of Formula 1 is characterized in that it is represented by any one of the following compounds 1 to 55.

In addition, the present invention is a compound of Formula 1; And it provides a composition for a green phosphorescent host comprising a compound of Formula 2 below.

[Formula 1]

(R ₁ and R ₂ are independently substituted or unsubstituted C6~ C50 aryl, or substituted or unsubstituted heteroaryl having 3 to 50 nuclear atoms.)

[Formula 2]

(R ₃ and R ₄ are independently substituted or unsubstituted C6~ C50 aryl, or substituted or unsubstituted heteroaryl having 3 to 50 nuclear atoms.)

In one embodiment of the present invention, the weight ratio of the compound of Formula 1 and the compound of Formula 2 is 10-30:70-90.

In addition, the present invention provides an organic electroluminescent device comprising the green phosphorescent host compound or the green phosphorescent host composition in a light emitting layer.

An object of the present invention is to provide a green phosphorescent host compound capable of improving luminous efficiency, lifespan and color purity of a device, having a low deposition temperature, excellent thermal denaturation characteristics, and lowering a driving voltage.

The green phosphorescent host compound of the present invention can be applied to a light emitting layer of an organic light emitting diode, an organic light emitting device, etc. to improve the light emitting efficiency, lifespan, color purity, stability, etc. of the device.

1 and 2 show the peak positions of the mass spectrum of the green phosphorescent host compounds 1 to 155.

Since the present invention is capable of making various changes and having various embodiments, specific embodiments will be illustrated and described in the detailed description. However, this is not intended to limit the present invention to a specific embodiment, it should be understood to include all modifications, equivalents and substitutes included in the spirit and scope of the present invention. In the description of the present invention, when it is determined that a detailed description of a related known technology may obscure the gist of the present invention, the detailed description thereof will be omitted.

The present invention relates to a green phosphorescent host compound having a structure of Formula 1, Formula 2 or Formula 3 below.

[Formula 1]

(R ₁ and R ₂ are independently substituted or unsubstituted C6~ C50 aryl, or substituted or unsubstituted heteroaryl having 3 to 50 nuclear atoms.)

[Formula 2]

(R ₃ and R ₄ are independently substituted or unsubstituted C6~ C50 aryl, or substituted or unsubstituted heteroaryl having 3 to 50 nuclear atoms.)

[Formula 3]

(R ₅ and R ₆ are independently substituted or unsubstituted C6~ C50 aryl, or substituted or unsubstituted heteroaryl having 3 to 50 nuclear atoms.)

The aryl and heteroaryl are deuterium, halogen, cyano group, nitro group, hydroxyl group, amino group, C1~ C50 alkyl group, C2~ C50 alkenyl group, C2~ C50 alkynyl group, C6~ C50 aryl group, number of nuclear atoms It may be substituted with one or more substituents selected from the group consisting of 3 to 50 heteroaryl groups and C1 to C50 alkyloxy groups, and when substituted with a plurality of substituents, these may be the same or different from each other.

The green phosphorescent host compound is applied to a light emitting layer of an organic light emitting diode, an organic light emitting tube device, etc. to improve the luminous efficiency, lifespan, color purity, stability, etc. of the device, and can lower the driving voltage.

The compound of Formula 1 may be represented by any one of Compounds 1 to 55 below.

In addition, the compound of Formula 2 may be represented by any one of the following compounds 56 to 155.

The peak positions of the mass spectra of the green phosphorescent host compounds 1 to 155 are shown in FIGS. 1 and 2 .

In addition, the present invention is a compound of Formula 1; And it relates to a composition for a green phosphorescent host comprising a compound of Formula 2 below.

[Formula 1]

(R ₁ and R ₂ are independently substituted or unsubstituted C6~ C50 aryl, or substituted or unsubstituted heteroaryl having 3 to 50 nuclear atoms.)

[Formula 2]

(R ₃ and R ₄ are independently substituted or unsubstituted C6~ C50 aryl, or substituted or unsubstituted heteroaryl having 3 to 50 nuclear atoms.)

The weight ratio of the compound of Formula 1 and the compound of Formula 2 is preferably 10-30:70-90, and when the above numerical range is satisfied, the luminous efficiency, lifespan, color purity and stability of the device can be maximized.

In addition, the composition of the present invention may further include a compound of Formula 3 below.

[Formula 3]

(R ₅ and R ₆ are independently substituted or unsubstituted C6~ C50 aryl, or substituted or unsubstituted heteroaryl having 3 to 50 nuclear atoms.)

The weight ratio of the compound of Formula 1, the compound of Formula 2, and the compound of Formula 3 is preferably 20-40:100:5-15, and when the above numerical range is satisfied, it is possible to maximize the luminous efficiency, lifespan and stability of the device. can

The present invention also relates to an organic electroluminescent device comprising the green phosphorescent host compound or the green phosphorescent host composition in a light emitting layer.

The green phosphorescent host compound and composition of the present invention can be applied to a light emitting layer of an organic light emitting diode, an organic light emitting device, etc. to improve the luminous efficiency, lifespan, color purity, stability, etc. of the device.

Hereinafter, the present invention will be described in detail through Examples and Comparative Examples. The following examples are only exemplified for the practice of the present invention, and the content of the present invention is not limited by the following examples.

(Synthesis of compound 1-1)

In a flask, 1-Bromo-4-chloro-2-iodobenzene (10g, 31.5mmol, 1eq), 2-Bromophenylboronic acid (6.3g, 31.5mmol, 1eq), Pd(PPh ₃ ) ₄ (1.09g, 0.95mmol, 0.03) eq), K ₂ CO ₃ (13g, 94.5 mmol, 3eq) and THF/H ₂ O (3:1) were added and stirred under reflux for 4 hours. After the reaction was completed, the organic layer was extracted, moisture was removed with magnesium sulfate, and the solution was concentrated under reduced pressure. Compound 1-1 was obtained through recrystallization (9.04 g, 83%).

(Synthesis of compound 1-2)

After putting 2,2'-Dibromo-5-chlorobiphenyl (5g, 14.4mmol, 1eq) and THF (40ml) in a flask, n-butyl lithium (1.6M in hexane, 18ml, 28.8mmol, 2eq) at 0°C ) was added dropwise and stirred at room temperature for 1 hour. PBr ₃ (3.9 g, 14.4 mmol, 1eq) was added to the solution under liquid nitrogen and the reaction mixture was stirred at -110 °C. The precipitate was filtered and the reaction was concentrated under reduced pressure. Compound 1-2 was obtained through recrystallization (2.57 g, 60%).

(Synthesis of compound P-1)

Compound 1-2 (3g, 10.1mmol, 1eq), naphthalene-2-boronic acid pinacol ester (2.6g, 10.1mmol, 1eq), Pd(PPh ₃ ) ₄ (0.35g, 0.3mmol, 0.03eq), NaOH (0.8g, 20.2mmol, 2eq) and THF/H ₂ O (3:1) were added and stirred under reflux for 4 hours. After the reaction was completed, the organic layer was extracted, moisture was removed with magnesium sulfate, and the solution was concentrated under reduced pressure. Compound P-1 was obtained through column chromatography (82%).

Various compounds P-1 were obtained by variously changing the substituents of R1.

(Synthesis of compound P-2)

Compound P-1 dissolved in 15 ml of DCM was placed in a flask, and 30% hydrogen peroxide (1.3eq) was added dropwise. After stirring the reactant for 1 hour, when the reaction was completed, the organic layer washed with brine was extracted, moisture was removed with magnesium sulfate, and the solution was concentrated under reduced pressure. Compound P-2 was obtained through recrystallization (83%).

Various compounds P-2 were obtained by variously changing the substituents of R1.

(Synthesis of compounds of Formulas 1 to 3)

In a flask, place compound P-1 or compound P-2 (5 g, 1eq), compound P-3 (1eq), Pd ₂ (dba) ₃ (2 mol%), K ₃ PO ₄ (3eq), x-phos (4 mol%) ) and Toluene/H ₂ O were added and stirred under reflux overnight. After the reaction was completed, the organic layer was extracted, moisture was removed with magnesium sulfate, and the solution was concentrated under reduced pressure. A compound of Formula 1, a compound of Formula 2, or a compound of Formula 3 was obtained through recrystallization (83%).

[Example 1]

According to the above synthesis method, a compound of Formula 1 (Compound 9) was prepared.

[Example 2]

According to the above synthesis method, a compound of Formula 2 (Compound 73) was prepared.

[Example 3]

According to the above synthesis method, a compound of Formula 2 (Compound 135) was prepared.

[Example 4]

According to the above synthesis method, a compound of Formula 3 was prepared.

[Example 5]

20 parts by weight of the compound of Example 1 and 80 parts by weight of the compound of Example 2 were mixed to prepare a composition.

[Example 6]

30 parts by weight of the compound of Example 1, 100 parts by weight of the compound of Example 2, and 10 parts by weight of the compound of Example 4 were mixed to prepare a composition.

[Comparative Example 1]

The compound of the following formula was used.

The luminous efficiency and color coordinates were measured using the compounds and compositions prepared in Examples and Comparative Examples, and the results are shown in Table 1 below.

Luminous Efficiency (cd/A) Luminous Efficiency (lm/W) Color coordinates (x, y) Example 1 49.0 32.1 0.3031, 0.6201 Example 2 50.3 35.4 0.3038, 0.6211 Example 3 49.6 33.8 0.3032, 0.6211 Example 4 48.5 30.9 0.3029, 0.6198 Example 5 51.8 37.2 0.3052, 0.6238 Example 6 52.0 37.8 0.3048, 0.6224 Comparative Example 1 37.2 18.3 0.3010, 0.6182

As can be seen from the above table, it can be seen that the Example has superior luminous efficiency and color coordinates compared to the Comparative Example, and in particular, Examples 2, 5, and 6 have the best characteristics.

Claims (5)

A green phosphorescent host compound having a structure of Formula 1, Formula 2, or Formula 3.
[Formula 1]

(R ₁ and R ₂ are independently substituted or unsubstituted C6~ C50 aryl, or substituted or unsubstituted heteroaryl having 3 to 50 nuclear atoms.)
[Formula 2]

(R ₃ and R ₄ are independently substituted or unsubstituted C6~ C50 aryl, or substituted or unsubstituted heteroaryl having 3 to 50 nuclear atoms.)
[Formula 3]

(R ₅ and R ₆ are independently substituted or unsubstituted C6~ C50 aryl, or substituted or unsubstituted heteroaryl having 3 to 50 nuclear atoms.)
According to claim 1,
The compound of Formula 1 is a green phosphorescent host compound, characterized in that it is represented by any one of the following compounds 1 to 55.

A compound of Formula 1; and
A composition for a green phosphorescent host comprising a compound of Formula 2 below.
[Formula 1]

(R ₁ and R ₂ are independently substituted or unsubstituted C6~ C50 aryl, or substituted or unsubstituted heteroaryl having 3 to 50 nuclear atoms.)
[Formula 2]

(R ₃ and R ₄ are independently substituted or unsubstituted C6~ C50 aryl, or substituted or unsubstituted heteroaryl having 3 to 50 nuclear atoms.)
4. The method of claim 3,
The composition for a green phosphorescent host, characterized in that the weight ratio of the compound of Formula 1 and the compound of Formula 2 is 10-30:70-90.
An organic electroluminescent device comprising the green phosphorescent host compound of claim 1 in a light emitting layer.

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