KR102317277B1 - Organic electroluminescent device comprising carbazole and pyridine constituent unit materials - Google Patents

Abstract

The present invention provides an organic electroluminescent device comprising a carbazole and pyridine constituent unit material, which includes a cathode, an anode and an organic layer, wherein the organic layer includes a hole transport layer, a light emitting layer, a hole blocking layer and One of the electron transport layers, the organic layer includes a compound represented by formula (I), wherein R ¹ and R ² are independently hydrogen, C1-C4 substituted or unsubstituted alkyl, C2-C4 substituted or unsubstituted alkenyl, C2-C4 substituted or unsubstituted alkynyl, C6-C10 substituted or unsubstituted aryl containing one or more substituents, aromatic hydrocarbon group, C3- heteroaryl containing one or more heteroatoms, substituted or unsubstituted, containing one or more substituents of C8. The experimental results show that the electroluminescence performance of OLEDs containing carbazole and pyridine constituent unit materials is excellent.

Description

Organic electroluminescent device comprising carbazole and pyridine constituent unit materials

The present invention relates to an organic light emitting diode, and more particularly, to an organic electroluminescent device including a carbazole and pyridine constituent unit material, wherein the material forms a thin film by vacuum deposition, and the organic light emitting diode It is used as a host material for a light emitting layer in a diode device.

Recently, as a lighting and display technology with excellent prospects for application, organic light emitting diodes (OLEDs) are receiving widespread attention in academia and industry. OLED devices have characteristics such as self-luminescence, wide viewing angle, short response time, and the possibility of manufacturing flexible devices, making them a strong competitor in the field of next-generation display and lighting technologies. However, current OLED still has problems such as low efficiency and short lifespan, so additional research is needed.

및 덱스터 에너지 전달 방식을 통해 게스트로 전달되며, 여기된 게스트 방사 발광은 기저 상태로 돌아온다. 따라서 고효율 PHOLED 소자를 얻기 위해서는 신규한 고성능의 호스트 물질을 개발하는 것이 중요하다.The organic light emitting diode is an electroluminescent device, and under voltage driving, electrons and holes flow into the light emitting layer through the electron transport layer and the hole transport layer, respectively, and recombine to form excitons. After that, excitons are excited by transferring energy to organic molecules having light-emitting properties, and when the excited-state molecules return to the ground state, radiative transition occurs and emits light. Since Forrest et al. reported electroluminescent phosphorescent devices (PHOLEDs) in 1998, PHOLEDs have attracted much attention due to their high efficiency use of triplet and singlet exciton emission. A high-efficiency PHOLED device typically has a multi-layer structure, and has the advantage of conveniently controlling processes such as carrier injection, transport, and recombination. When the doping concentration of the guest material in the light emitting layer is high, concentration quenching and T ₁ -T ₁ annihilation may occur, so that luminous efficiency may be reduced. To solve this problem, a guest material is typically doped into the host material to "dilute" the concentration of the guest material. Excitons formed on the host

and Dexter energy transfer to the guest, and the excited guest radium returns to the ground state. Therefore, in order to obtain a high-efficiency PHOLED device, it is important to develop a novel high-performance host material.

Host materials can be divided into three types: hole type, electron type and bipolar type. When a hole-type host material is used, hole and electron recombination typically occurs at the interface between the light emitting layer and the electron transport layer, and when an electron type host material is used, hole and electron recombination typically occurs at the interface between the light emitting layer and the hole transport layer. Here, it can be seen that the unipolar host material tends to narrow the carrier recombination region. The narrow recombination region is not beneficial to the improvement of device performance because the _{local exciton density is increased to accelerate the T 1} -T _{1 annihilation.} On the other hand, the bipolar host material can effectively solve the above problem. The use of a bipolar host material is of great interest from researchers in this field because it can balance holes and electrons in the device, widen the carrier recombination region, and simplify the device structure.

It is an object of the present invention to provide a novel anode-type host material based on pyridine and carbazole constituent units, which is used in an organic light emitting diode device to obtain excellent luminous efficiency.

An organic electroluminescent device comprising a carbazole and pyridine constituent unit material includes a cathode, an anode and an organic layer, wherein the organic layer is at least one of a hole transport layer, a light emitting layer, a hole blocking layer, and an electron transport layer, and the organic layer has Formula (I) compounds represented by

Ar is one of the following groups.

Here, R ¹ and R ² are independently hydrogen, C1-C4 substituted or unsubstituted alkyl, C2-C4 substituted or unsubstituted alkenyl, C2-C4 substituted or unsubstituted alkynyl (alkynyl), a substituted or unsubstituted aryl containing one or more substituents of C6-C10, an aromatic hydrocarbon group, a substituted or unsubstituted heteroatom containing one or more substituents of C3-C8 containing one or more heteroatoms heteroaryl; The substitution is substituted with a halogen atom, C1-C4 alkyl.

Preferably, R ¹ and R ² are independently selected from hydrogen, C1-C4 alkyl, one or more substituted or unsubstituted C6-C10 aryl, aromatic hydrocarbon groups,

More preferably, R ¹ and R ² are independently selected from hydrogen, methyl, tert-butyl, phenyl, tolyl, naphthyl,

More preferably, R ¹ and R ² are the same substituents selected from hydrogen, tert-butyl, phenyl and methyl,

Particularly preferably, wherein Ar is a group,

R¹ 및 R²는 수소, tert-부틸, 페닐로부터 선택된 동일한 치환기이다.

R ¹ and R ² are identical substituents selected from hydrogen, tert-butyl, phenyl.

More preferably, wherein Ar is one of the following groups.

R ¹ is hydrogen, and R ² is tert-butyl, phenyl, tolyl, or naphthyl.

As mentioned above, the compounds of formula (I) of the present invention are as follows, but are not limited to the structures listed below.

Preferably, the structure of the compound represented by the formula (I) is as follows.

The organic light emitting diode device includes a cathode, an anode and an organic layer, wherein the organic layer is at least one of a hole transport layer, a light emitting layer, a hole blocking layer and an electron transport layer, and each of these organic layers does not necessarily exist.

The hole transport layer, the hole blocking layer, the light emitting layer and / or the electron transport layer contains the compound of formula (I).

The compound of formula (I) is a host material used in the light emitting layer.

The total thickness of the device organic layer of the present invention is 1 to 1000 nm, preferably 1 to 500 nm, more preferably 5 to 300 nm.

The organic layer may be formed into a thin film by vapor deposition or a solution method.

Experimental results show that when the organic host material of the present invention is used for OLED, the luminous efficiency is excellent, and thus it is likely to be utilized in the field of organic electroluminescent devices.

1 is a structural diagram of an organic electroluminescent device according to the present invention.

In order to explain the present invention in more detail, the following examples are specifically listed, but the present invention is not limited thereto.

Example 1

Synthetic route of compound 1

Synthesis of compound 1

Under nitrogen protection, compound a (3.2 g, 9.5 mmol) (reference: J. Heterocycl. Chem. , 2016, 53, 615-619 synthesis), compound la (3.0 g, 10.5 mmol) (reference: J. Mater) Chem. C, 2015, 3, 12529-12538), Pd(PPh ₃ ) ₄ (208 mg, 0.2 mmol), dioxane (40 mL) and potassium carbonate aqueous solution (2 M, 5 mL) were sequentially placed in a Schlenk tube. add Heat to 80° C. and react for 12 hours. After cooling to room temperature, the reaction solution is added to water, extracted three times with dichloromethane, and the organic phases are combined. The organic layer was dried over anhydrous sodium sulfate, the solvent was removed, and the residue was separated by column chromatography to obtain a pale yellow solid (5.4 g, yield 85%), and the purity was 99.8% after sublimation. MS (EI): m/z : 662.5 (M ⁺ )

Example 2

Synthetic route of compound 2

Synthesis of compound 2

Under nitrogen protection, compound a (2.2 g, 6.5 mmol), compound 2a (2.3 g, 8.0 mmol) (reference: J. Mater. Chem. C, 2015, 3, 12529-12538 synthesis), Pd (PPh ₃ ) ₄ (208mg, 0.2mmol), dioxane (40mL) and potassium carbonate aqueous solution (2M, 5mL) are sequentially added to the Schlenk tube. Heat to 80° C. and react for 12 hours. After cooling to room temperature, the reaction solution is added to water, extracted three times with dichloromethane, and the organic phases are combined. The organic layer was dried over anhydrous sodium sulfate, the solvent was removed, and the residue was separated by column chromatography to obtain a pale yellow solid (3.1 g, yield 72%), and the purity was 99.8% after sublimation. MS(EI): m /z : 662.5(M ⁺ )

Example 3

Synthetic route of compound 3

Synthesis of compound 3

Under nitrogen protection, compound a (3.2 g, 9.5 mmol), compound 3a (3.0 g, 10.5 mmol) (reference: J. Mater. Chem. C, 2015, 3, 12529-12538 synthesis), Pd (PPh ₃ ) ₄ (208mg, 0.2mmol), dioxane (40mL) and potassium carbonate aqueous solution (2M, 5mL) are sequentially added to the Schlenk tube. Heat to 80° C. and react for 12 hours. After cooling to room temperature, the reaction solution is added to water, extracted three times with dichloromethane, and the organic phases are combined. The organic layer was dried over anhydrous sodium sulfate, the solvent was removed, and the residue was separated by column chromatography to obtain a pale yellow solid (3.4 g, yield 54%), and the purity was 99.8% after sublimation. MS (EI): m/z : 662.2 (M ⁺ )

Example 4

Synthetic route of compound 12

Synthesis of compound 12

Under nitrogen protection, compound a (1.2 g, 3.6 mmol), compound 12a (1.1 g, 3.83 mmol) (reference: CN105601613A synthesis), Pd(PPh ₃ ) ₄ (50 mg, 0.04 mmol), dioxane (20 mL) and Aqueous potassium carbonate solution (2M, 5mL) is sequentially added to the Schlenk tube. Heat to 80° C. and react for 12 hours. After cooling to room temperature, the reaction solution is added to water, extracted three times with dichloromethane, and the organic phases are combined. The organic layer was dried over anhydrous sodium sulfate, the solvent was removed, and the residue was separated by column chromatography to obtain a pale yellow solid (2.4 g, yield 83%), and the purity was 99.7% after sublimation. MS(EI): m /z : 814.5(M ⁺ )

Example 5

Fabrication of the organic electroluminescent device (1)

An OLED is manufactured using the organic host material of the present invention, as shown in FIG. 1 .

First, the transparent conductive ITO glass substrate 10 (with the anode 20 on the upper surface) is sequentially cleaned with a detergent solution, deionized water, ethanol, acetone, and deionized water, and then treated again with oxygen plasma for 30 seconds.

Thereafter, HATCN having a thickness of 10 nm is deposited on the ITO as the hole injection layer 30 .

Thereafter, the compound TAPC is deposited to form the hole transport layer 40 having a thickness of 40 nm.

Thereafter, AG-Pt-1 (10%), TCTA (60%) and Compound 1 (30%) having a thickness of 30 nm are deposited on the hole transport layer as the emission layer 50 .

Thereafter, 50 nm thick TmPyPb is deposited as the hole blocking layer 60 on the emission layer.

Finally, 1 nm LiF is deposited as the electron injection layer 70 and 100 nm Al is deposited as the device cathode 80 .

The structural formula of the element

^{The fabricated device emits green light with a brightness of 9060 cd/m 2} and a current efficiency of 45.3 cd/A under an operating current density of 20 mA/cm ^{2 .} The device made of the organic material of the present invention has excellent electroluminescence performance to satisfy the requirements of a host material for a high-performance OLED device.

10: glass substrate
20: positive electrode
30: hole injection layer
40: hole transport layer
50: light emitting layer
60: hole blocking layer
70: electron injection layer
80: cathode

Claims (10)

In the organic electroluminescent device comprising a carbazole and pyridine constituent unit material,
a cathode, an anode and an organic layer, wherein the organic layer is at least one of a hole transport layer, a light emitting layer, a hole blocking layer, and an electron transport layer, and the organic layer contains a compound represented by Formula (I),

Ar is a group,

wherein R ¹ and R ² are the same and are selected from hydrogen, C1-C4 substituted or unsubstituted alkyl, and substituted or unsubstituted aryl containing one or more substituents of C6-C10; The substitution is substituted with a halogen atom or C1-C4 alkyl,
Or, Ar is a group,

wherein R ¹ is hydrogen, R ² is C6-C10 substituted or unsubstituted aryl containing one or more substituents; The substitution is an organic electroluminescent device comprising a carbazole and pyridine constituent unit material, characterized in that substituted with a halogen element or C1-C4 alkyl. According to claim 1,
Ar is a group,

wherein R ¹ and R ² are the same and are selected from hydrogen, C1-C4 alkyl, and substituted or unsubstituted aryl containing one or more substituents of C6-C10. 3. The method of claim 2,
wherein R ¹ and R ² are the same and are selected from hydrogen, methyl, tert-butyl, phenyl, tolyl, and naphthyl. electroluminescent device. 4. The method of claim 3,
wherein R ¹ and R ² are the same and are selected from hydrogen, tert-butyl, phenyl and methyl. 5. The method of claim 4,
wherein Ar is the following group,

wherein R ¹ and R ² are the same and are selected from hydrogen, tert-butyl, and phenyl. 3. The method of claim 2,
wherein Ar is one of the following groups,

Here, R ¹ is hydrogen, and R ² is phenyl, tolyl, or naphthyl. According to claim 1,
The compound represented by formula (I) is an organic electroluminescent device, characterized in that one of the following.

8. The method of claim 7,
The compound represented by the formula (I) is an organic electroluminescent device, characterized in that one of the following.

9. The method of claim 8,
The compound of formula (I) is an organic electroluminescent device, characterized in that the host material in the light emitting layer. According to claim 1,
The total thickness of the organic layer is 1 to 1000 nm, the organic layer is an organic electroluminescent device, characterized in that the thin film can be formed by vapor deposition or solution method.

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