CN116391008A

CN116391008A - Carbazole-containing compound and organic electroluminescent device

Info

Publication number: CN116391008A
Application number: CN202280006488.1A
Authority: CN
Inventors: 钱超; 许军; 朱东林; 黄明辉
Original assignee: Nanjing Topto Materials Co Ltd
Current assignee: Nanjing Topto Materials Co Ltd
Priority date: 2021-06-30
Filing date: 2022-02-11
Publication date: 2023-07-04
Also published as: CN113480526A; WO2023273357A1

Abstract

The invention discloses a carbazole-containing compound and an organic electroluminescent device, wherein the carbazole-containing compound is formed by connecting two carbazole, triazine and dibenzofuran in a specific mode. In addition, heavy hydrogen (deuterium) is introduced into the traditional organic materials, the introduction of deuterium improves the phase solubility of the materials and the doping materials, improves the interface stability, and further greatly improves the luminous efficiency and stability of the device, and meanwhile, the compound can be matched with the doping materials better due to the introduction of deuteration, so that the service life and luminous efficiency of the device are further improved.

Description

Carbazole-containing compound and organic electroluminescent device

Technical Field

The invention relates to the technical field of organic electroluminescence, in particular to a carbazole-containing compound and an organic electroluminescent device.

Background

Organic electroluminescent devices (OLEDs) are a research hotspot in the world flat panel display field in recent years. Has the following advantages compared with LCD

The organic plastic layer of an OLED is thinner, lighter and more flexible than the crystalline layer of an LED (light emitting diode) or LCD (liquid crystal display);

the light-emitting layer of the OLED is light, so that the base layer of the OLED can be made of a material rich in flexibility, but not rigid materials, the OLED base layer is made of a plastic material, and the LEDs and the LCD use a glass base layer;

an OLED is a current-type organic light emitting device, which is a phenomenon of emitting light by injection and recombination of carriers, and the intensity of the light emission is proportional to the current injected. Under the action of an electric field, holes generated by the anode and electrons generated by the cathode of the OLED move, are respectively injected into the hole transport layer and the electron transport layer, and migrate to the light emitting layer. When the two meet at the light emitting layer, an energy exciton is generated, thereby exciting the light emitting molecule to finally generate visible light.

Since there is a great gap between the external quantum efficiency and the internal quantum efficiency of the OLED, the development of the OLED is greatly restricted, and therefore how to improve the light extraction efficiency of the OLED is also a hot spot of research. The interface of the ITO film and the glass substrate and the interface of the glass substrate and air can generate total reflection, the light emitted to the front external space of the OLED device occupies about 20 percent of the total quantity of the organic material film EL, and the rest about 80 percent of light is mainly limited in the organic material film, the ITO film and the glass substrate in a guided wave mode, so that the development and the application of the OLED are seriously restricted, the total reflection effect in the OLED device is reduced, the proportion of light coupled to the front external space of the device is improved, and the performance of the device is further improved.

In order to fully develop the excellent characteristics of the organic light-emitting device, materials constituting the organic layer in the device, for example, hole injection materials, hole transport materials, light-emitting materials, electron transport materials, electron injection materials, and the like are stable and effective materials as backsides, and thus development of new materials is continuously demanded.

Disclosure of Invention

The invention aims to: the invention provides a carbazole-containing compound and an organic electroluminescent device.

In order to achieve the above purpose, the technical scheme adopted by the invention is as follows:

a carbazole-containing compound characterized by having a group represented by the following structural formula:

R1-R2 are each independently hydrogen, deuterium, deuterated or non-deuterated phenyl, deuterated or non-deuterated biphenyl;

l is a single bond, phenyl or naphthyl;

r3 is a deuterated C3-C20 cycloalkyl group, a deuterated C6-C20 aromatic group;

p and n are each independently 0, 1, 2, 3, 4.

Preferably, the R3 is selected from deuterated phenyl, deuterated naphthyl, deuterated phenanthryl, deuterated C3-C12 cycloalkyl groups;

the L is connected to the 1 st position of dibenzofuran, and R1-R2 are each independently hydrogen, deuterium, deuterated or non-deuterated phenyl.

Further, the R3 is selected from one of the following groups:

further, it is any one of the following compounds:

an organic electroluminescent device comprising a first electrode, a second electrode, and an organic layer formed between the first electrode and the second electrode, wherein the organic layer contains the compound.

Further, the organic layer comprises a hole injection layer, a first hole transport layer, a second hole transport layer, a light emitting layer, a hole blocking layer, an electron transport layer and an electron injection layer; at least one layer of the hole injection layer, the first hole transport layer, the second hole transport layer, the light emitting layer, the hole blocking layer, the electron transport layer and the electron injection layer contains the compound.

Further, the light-emitting layer contains the above compound.

Still further, the light-emitting layer further contains at least one of the following compounds G1 to G56:

an electronic display device comprising the organic electroluminescent device.

An OLED lighting device comprising the organic electroluminescent device.

The room temperature of the invention is 25+/-5 ℃.

The invention has the beneficial effects that:

the invention designs a compound used as an organic electroluminescent material, which has the following characteristics: firstly, heavy hydrogen (deuterium) is introduced into the traditional organic material, the introduction of deuterium improves the phase solubility of the material and the doped material, improves the interface stability, and further greatly improves the luminous efficiency and stability of the device, and meanwhile, the introduction of deuteration enables the compound to be matched with the doped material better, so that the service life and luminous efficiency of the device are further improved. Secondly, deuteration can lead to weakening of intramolecular vibration of the material, so that occurrence of non-radiative transition is reduced, internal quantum efficiency of the material is improved, stability of the device is improved, luminous efficiency and service life of the device are improved, molecular weight of the material can be adjusted by introducing deuteration, evaporation temperature of the material is adjusted, and the material is matched with electron-donating group material better, and stability and service life of the device are improved. And thirdly, two carbazole groups are arranged in the molecule of the material, and carbazole groups have higher triplet state energy levels, so that the compound has higher triplet state energy levels, and the characteristic effectively avoids the reverse transfer of energy from a doping material to a main material, thereby improving the luminous efficiency of the device.

Through device verification, the organic electroluminescent device prepared by using the compound disclosed by the invention has better luminous efficiency and service life.

Drawings

Fig. 1 is a schematic structural view of an organic electroluminescent device according to the present invention.

The reference numerals in the figures represent:

1-anode, 2-hole injection layer, 3-first hole transport layer, 4-second hole transport layer, 5-light emitting layer, 6-hole blocking layer, 7-electron transport layer, 8-electron injection layer, 9-cathode.

FIG. 2 is an HPLC chart of Compound 1 prepared in example 1 of the present invention.

FIG. 3 is a DSC chart of Compound 1 prepared in example 1 of the present invention, and as can be seen from FIG. 3, the Tm value of Compound 1 is 304.33 ℃.

FIG. 4 is a TGA spectrum of the compound 1 prepared in example 1 of the present invention, and as can be seen from FIG. 4, the thermal weight loss temperature Td value is 477.67 ℃.

Fig. 5 is a life chart of the organic electroluminescent device in application example 1 and comparative example 1 of the present invention; as can be seen from fig. 5, the T97% lifetimes of the organic electroluminescent devices according to the present invention, which were prepared in application example 1 and comparative example 1, were 621h and 454h, respectively.

Detailed Description

Embodiments of the various aspects are further illustrated and described below. It should be understood that the description herein is not intended to limit the claims to the particular aspects described. On the contrary, the intent is to cover alternatives, modifications and equivalents as included within the spirit and scope of the disclosure as defined by the appended claims.

As used herein, the term "substituted" or "unsubstituted" in the sense that at least one hydrogen in the group is re-coordinated to a hydrocarbyl, hydrocarbon derivative, halogen, or cyano (-CN). The term "unsubstituted" means that at least one hydrogen in the group does not re-coordinate with a hydrocarbyl group, hydrocarbon derivative group, halogen, or cyano (-CN). Examples of hydrocarbyl or hydrocarbon derivative groups may include, but are not limited to, C1 to C20 alkyl, C2 to C20 alkenyl, C2 to C20 alkynyl, C6 to C20 aryl, C5 to C20 heteroaryl, C1 to C20 alkylamino, C6 to C20 arylamino, C6 to C20 heteroarylamino, C6 to C20 arylheteroarylamino, and the like.

The specific conditions are not noted in the examples and are carried out according to conventional conditions or conditions recommended by the manufacturer. The reagents or apparatus used were conventional products commercially available without the manufacturer's attention.

Example 1:

the synthesis method of the compound 1 is as follows:

compound 1-a (1 eq,10g,445.9g/mol,22.43 mmol), compound 1-b (1.1 eq,9.26g,375.28g/mol,24.67 mmol) were dissolved in 200mL of toluene under nitrogen, palladium acetate (0.25 g,224.51g/mol,1.12 mmol), X-phos (0.26 g,476.72g/mol,1.12 mmol), potassium carbonate (9.30 g,138.21g/mol,67.28 mmol) and 100mL of ethanol and 50mL of water were added and stirred overnight at 82℃to monitor the progress of the reaction by HPLC.

After monitoring that the compound 1-a is reacted completely by HPLC, stopping the reaction, cooling the reaction liquid to room temperature, adding 60mL of water, stirring for 20min, carrying out suction filtration to obtain a filter cake, leaching the filter cake with water and ethanol for 2 times, then drying the filter cake at 80 ℃ in vacuum for 6 hours, adding the dried filter cake into a 250mL three-neck flask, adding 100mL of o-dichlorobenzene, heating to 120 ℃ until the solid is completely dissolved, filtering the solution through a silica gel and an activated carbon funnel while the solution is hot to obtain a filtrate, naturally cooling the filtrate to room temperature, precipitating white solid, carrying out suction filtration to obtain the filter cake, carrying out secondary recrystallization operation on the filter cake, and obtaining the final target product compound 1 (6.38 g,9.69mmol, yield 43.2 percent) ESI-MS (M/z) (M+): theoretical 658.76, observed 659.22, elemental analysis (formula C45H22D5N 5O): theoretical value C,82.05; h,4.89; n,10.63; o,2.43; actual measurement C,82.09; h,4.85; n, 10.67; o,2.39.

Example 2:

the synthesis method of the compound 2 is as follows:

the preparation was carried out in substantially the same manner as in example 1 except that compound 1-b was replaced with compound 2-b to give the final objective compound 2 in a yield of 41.5% and ESI-MS (M/z) (M+): theoretical 710.83, observed 711.34, elemental analysis (formula C49H22D7N 5O): theoretical value C,82.79; h,5.10; n,9.85; o,2.25; actual measurement C,82.73; h,5.17; n,9.80; o,2.30.

Example 3:

the synthesis method of the compound 3 is as follows:

the preparation was carried out in substantially the same manner as in example 1 except that the compound 1-b was replaced with the compound 3-b to give the final objective compound 3 in a yield of 45.6% and ESI-MS (M/z) (M+): theoretical 710.83, observed 711.21, elemental analysis (formula C49H22D7N 5O): theoretical value C,82.79; h,5.10; n,9.85; o,2.25; measured value C,82.83; h,5.06; n,9.89; o,2.22.

Example 4:

the synthesis method of the compound 8 is as follows:

the preparation was carried out in substantially the same manner as in example 1 except that compound 1-a was replaced with compound 4-a to give the final objective compound 8 in a yield of 51.6% and ESI-MS (M/z) (M+): theoretical 666.81, observed 667.25, elemental analysis (formula C45H14D13N 5O): theoretical value C,81.05; h,6.04; n,10.50; o,2.40; actual measurement C,81.09; h,6.00; n,10.57; o,2.34.

Example 5:

the synthesis method of the compound 10 is as follows:

the preparation was carried out in substantially the same manner as in example 1 except that the compound 1-b was replaced with the compound 5-b to give the final objective compound 10 in a yield of 44.7% and ESI-MS (M/z) (M+): theoretical 784.91, observed 783.98, elemental analysis (formula C55H28D5N 5O): theoretical C,84.16; h,4.88; n,8.92; o,2.04; actual measurement C,84.10; h,4.94; n,8.90; o,2.06.

Example 6:

the synthesis method of the compound 18 is as follows:

the preparation was carried out in substantially the same manner as in example 1 except that the compound 1-b was replaced with the compound 6-b to obtain the final objective compound 18 in a yield of 38.5% and ESI-MS (M/z) (M+): theoretical 786.93, observed 787.83, elemental analysis (formula C55H26D7N 5O): theoretical value C,83.95; h,5.12; n,8.90; o,2.03; actual measurement C,83.97; h,5.10; n,8.84; o,2.09.

Example 7:

the synthesis method of the compound 24 is as follows:

the preparation was carried out in substantially the same manner as in example 1 except that the compound 1-b was replaced with the compound 7-b to give the final objective compound 24 in a yield of 40.8% and ESI-MS (M/z) (M+): theoretical 786.93, observed 787.35, elemental analysis (formula C55H26D7N 5O): theoretical value C,83.95; h,5.12; n,8.90; o,2.03; actual measurement C,83.99; h,5.08; n,8.85; o,2.08.

Example 8:

the synthesis method of the compound 32 is as follows:

the preparation was carried out in substantially the same manner as in example 1 except that compound 1-a was replaced with compound 8-a to give the final objective compound 32 in a yield of 50.8% and ESI-MS (M/z) (M+): theoretical 734.86, observed 735.60, elemental analysis (formula C51H26D5N 5O): theoretical value C,83.36; h,4.94; n,9.53; o,2.18; actual measurement C,83.30; h,4.99; n,9.53; o,2.18.

Example 9:

the synthesis method of the compound 34 is as follows:

the preparation was carried out in substantially the same manner as in example 1 except that compound 1-a was replaced with compound 9-a and compound 1-b was replaced with compound 9-b to obtain the final objective product compound 34 in 37.4% yield, ESI-MS (M/z) (M+): theoretical 786.93, observed 787.19, elemental analysis (formula C55H26D7N 5O): theoretical value C,83.95; h,5.12; n,8.90; o,2.03; actual measurement C,83.98; h,5.16; n,8.86; o,2.00.

Example 10:

the synthesis method of the compound 41 is as follows:

the preparation was carried out in substantially the same manner as in example 1 except that compound 1-a was replaced with compound 10-a and compound 1-b was replaced with compound 10-b to obtain the final objective product compound 41 in a yield of 35.8%, ESI-MS (M/z) (M+): theoretical 861.01, observed 861.55, elemental analysis (formula C61H32D5N 5O): theoretical value C,85.09; h,4.92; n,8.13; o,1.86; actual measurement C,85.04; h,4.97; n,8.17; o,1.82.

Example 11:

the synthesis method of compound 65 is as follows:

the preparation was carried out in substantially the same manner as in example 1 except that compound 1-a was replaced with compound 11-a to give the final objective compound 65 in a yield of 48.9% and ESI-MS (M/z) (M+): theoretical 734.86, observed 735.41, elemental analysis (formula C51H26D5N 5O): theoretical value C,83.36; h,4.94; n,9.53; o,2.18; actual measurement C,83.30; h,5.00; n,9.56; o,2.14.

Example 12:

the synthesis of compound 66 was as follows:

the preparation was carried out in substantially the same manner as in example 1 except that compound 1-a was replaced with compound 12-a to give final objective compound 66 in a yield of 50.6% and ESI-MS (M/z) (M+): theoretical 734.86, observed 735.22, elemental analysis (formula C51H26D5N 5O): theoretical value C,83.36; h,4.94; n,9.53; o,2.18; measured value C,83.39; h,4.91; n,9.58; o,2.12.

Material property testing:

the

compounds

1, 2, 3, 8, 10, 18, 24, 32, 34, 41, 65, 66 of the present invention were tested for the thermal weight loss temperature Td and the melting point Tm, and the test results are shown in table 1 below.

Note that: the thermal weight loss temperature Td is a temperature at which the weight loss is 5% in a nitrogen atmosphere, and is measured on a TGA N-1000 thermogravimetric analyzer with a nitrogen flow of 10mL/min, and a melting point Tm is measured by differential scanning calorimetry (DSC, new family DSC N-650) at a heating rate of 10 ℃/min.

Table 1:

project	Material	Td/℃	Tm/℃
Example 01	1	477.67	304.33
Example 02	2	463.41	317.52
Example 03	3	492.50	277.18
Example 04	8	485.71	328.41
Example 05	10	511.65	262.56
Example 06	18	475.26	235.35
Example 07	24	503.22	289.49
EXAMPLE 08	32	524.58	309.58
Example 09	34	460.46	247.17
Example 10	41	478.34	303.44
Example 11	65	484.62	265.06
Example 12	66	508.07	317.48

From the data, the compound synthesized by the invention has excellent thermal stability, which indicates that the compound conforming to the general structural formula of the invention has excellent thermal stability and can meet the use requirement of the organic electroluminescent material.

Device performance test:

application example 1:

ITO is adopted as the anode substrate material of the reflecting layer, and water, acetone and N are sequentially used ₂ Carrying out surface treatment on the surface of the material by plasma;

depositing 10nm of HT-1 doped with 5% HAT-CN over the ITO anode substrate to form a Hole Injection Layer (HIL);

evaporating HT-1 of 100nm above a Hole Injection Layer (HIL) to form a first Hole Transport Layer (HTL);

vacuum evaporating GP above the first Hole Transport Layer (HTL) to form a second hole transport layer (GPL) with a thickness of 30 nm;

the compound 1 and the G1 designed by the invention are used as green light main materials to carry out co-evaporation according to the mass ratio of 5:5, GD-1 is used as doping materials (the GD-1 dosage is 8% of the total mass of the compound 1 and the G1) to be evaporated on a second hole transport layer (GPL) to form a luminescent layer with the thickness of 30 nm;

evaporating HB-1 on the light-emitting layer to obtain a Hole Blocking Layer (HBL) with the thickness of 20 nm;

co-evaporating ET-1 and LiQ on a Hole Blocking Layer (HBL) according to the proportion of 5:5 to obtain an Electron Transport Layer (ETL) with the thickness of 30 nm;

mixing and evaporating magnesium (Mg) and silver (Ag) in a ratio of 9:1 to form an Electron Injection Layer (EIL) with a thickness of 50nm above an Electron Transport Layer (ETL);

thereafter, silver (Ag) was evaporated over the electron injection layer to form a cathode having a thickness of 100nm, DNTPD having a thickness of 50nm was deposited on the above cathode sealing layer, and in addition, the surface of the cathode was sealed with UV hardening adhesive and a sealing film (seal cap) containing a moisture scavenger to protect the organic electroluminescent device from oxygen or moisture in the atmosphere, so that the organic electroluminescent device was fabricated.

Application examples 2 to 12

The

compounds

2, 3, 8, 10, 18, 24, 32, 34, 41, 65, 66 in examples 2 to 12 of the present invention were used as green light host materials instead of the compound 1, and the other parts were the same as in application example 1, thereby producing organic electroluminescent devices of application examples 2 to 12.

Comparative examples 1 to 3:

the difference from application example 1 is that GH-1, GH-2 and GH-3 in CN112079824A are used as the green host material instead of the compound 1, respectively, and the remainder is the same as application example 1.

The organic electroluminescent device manufactured in the above application example and the organic electroluminescent device manufactured in the comparative example were characterized in that the current density was 10mA/cm ² The results of the measurement under the conditions of (2) are shown in Table 2.

Table 2:

as can be seen from the above Table 2, the compound of the present invention is applied to an organic electroluminescent device, and the luminous efficiency is greatly improved under the same current density, the starting voltage of the device is reduced, the power consumption of the device is relatively reduced, and the service life of the device is correspondingly improved.

The organic electroluminescent devices prepared in comparative examples 1 to 3 and application examples 1 to 5 were subjected to luminescence lifetime test, respectively, to obtain luminescence lifetime T97% data (time for which luminescence luminance was reduced to 97% of initial luminance), and the test equipment was a TEO luminescent device lifetime test system. The results are shown in Table 3:

table 3:

as can be seen from the above Table 3, the application of the compound of the present invention to organic electroluminescent devices has a greatly improved service life at the same current density, and has a wide application prospect.

Claims

A carbazole-containing compound characterized by having a group represented by the following structural formula:

R1-R2 are each independently hydrogen, deuterium, deuterated or non-deuterated phenyl, deuterated or non-deuterated biphenyl;

l is a single bond, phenyl or naphthyl;

r3 is a deuterated C3-C20 cycloalkyl group, a deuterated C6-C20 aromatic group;

p and n are each independently 0, 1, 2, 3, 4.
The organic compound of claim 1, wherein R3 is selected from the group consisting of deuterated phenyl, deuterated naphthyl, deuterated phenanthryl, deuterated C3-C12 cycloalkyl groups;

the L is connected to the 1 st position of dibenzofuran, and R1-R2 are each independently hydrogen, deuterium, deuterated or non-deuterated phenyl.
The organic compound according to claim 2, wherein R3 is selected from one of the following groups:
the organic compound according to claim 1, which is any one of the following compounds:
an organic electroluminescent device comprising a first electrode, a second electrode, and an organic layer formed between the first electrode and the second electrode, wherein the organic layer comprises the compound according to any one of claims 1 to 4.
The organic electroluminescent device of claim 5, wherein the organic layer comprises a hole injection layer, a first hole transport layer, a second hole transport layer, a light emitting layer, a hole blocking layer, an electron transport layer, an electron injection layer; at least one of the hole injection layer, the first hole transport layer, the second hole transport layer, the light emitting layer, the hole blocking layer, the electron transport layer, and the electron injection layer contains the compound according to any one of claims 1 to 4.
The organic electroluminescent device as claimed in claim 6, wherein the light-emitting layer contains the compound as claimed in any one of claims 1 to 4.
The organic electroluminescent device according to claim 7, wherein the light-emitting layer further comprises at least one of the following compounds G1 to G56:
an electronic display device comprising the organic electroluminescent device as claimed in claim 7.
An OLED lighting device comprising the organic electroluminescent device as claimed in claim 7.