Cyano-containing compound and application thereof

Abstract

The invention relates to the technical field of organic photoelectric materials, in particular to a cyano-containing compound and application thereof. The invention provides a cyano-containing compound. The cyano-containing compound has a structure as shown in a formula I in the specification. The cyano-containing compound provided by the invention has relatively good electron receiving capability, and meanwhile, interaction among molecules can be weakened by introducing a fluorene group with large steric hindrance; when the compound is applied to an organic electroluminescent device as an electron transport material, the current efficiency is improved, and the service life of the device is greatly prolonged.

Description

Technical Field

[0001] The present invention belongs to the technical field of organic optoelectronic materials, and particularly relates to a cyano-containing compound and its application. Background Art

[0002] Organic Light-Emitting Diode (hereinafter simply referred to as OLED) has the advantages of light weight, small size, wide viewing angle, fast response, wide operating temperature range, low energy consumption, high efficiency, good color purity, high clarity, good flexibility, etc., and can meet the new requirements of consumers for display technology, and has good application prospects in the fields of lighting and display.

[0003] An organic electroluminescent element is a self-luminous element that utilizes the following principle: by applying an electric field, the recombination of holes injected from the anode and electrons injected from the cathode can cause a fluorescent substance to emit light. It has the following structure: an anode, a cathode, and an organic material layer therebetween. In order to improve the efficiency and stability of the organic electroluminescent element, the organic material layer usually includes multiple layers with different materials, such as a hole injection layer HIL, a hole transport layer HTL, a light-emitting layer, an electron transport layer ETL, and an electron injection layer EIL. In such an organic light-emitting element, when a voltage is applied between the anode and the cathode, holes from the anode and electrons from the cathode are injected into the organic material layer, and the generated excitons emit light with a specific wavelength when migrating to the ground state. Among them, the hole transport layer can change the hole transport efficiency, light-emitting efficiency, lifetime, etc. of holes to the light-emitting layer.

[0004] Currently, the research on organic electroluminescent materials has been widely carried out in the academic and industrial fields. Designing and finding a compound as a new material for OLED to overcome the deficiencies that occur in the actual application process is the focus and future research and development trend of OLED material research work. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a cyano-containing compound and its application. Through the design of the structure of the cyano-containing compound, the obtained cyano-containing compound has excellent properties and is suitable as an electron transport material in organic electroluminescent devices.

[0006] To achieve this purpose, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a cyano-containing compound, and the cyano-containing compound has a structure shown in Formula I:

[0008]

[0009] Wherein, the R 1 、R 2Independently selected from C 1 ~C 12 alkyl, C 6 ~C 30 aryl or C 3 ~C 30 any one of heteroaryl;

[0010] L1 is selected from C 6 ~C 30 arylene or C 3 ~C 30 any one of heteroarylene;

[0011] n is selected from an integer of 0 to 1;

[0012] In the present invention, the C 1 ~C 12 alkyl is selected from methyl, ethyl, propyl, isopropyl, butyl, tert-butyl, pentyl, pivalyl, n-hexyl or cyclohexyl.

[0013] The C 6 ~C 30 aryl is selected from phenyl, biphenyl, terphenyl, naphthyl, anthryl, indenyl, fluorenyl, perylenyl, phenanthryl, pyrenyl, fluoranthenyl or benzo[ghi]perylenyl.

[0014] The C 6 ~C 30 arylene is selected from phenylene, biphenylene, terphenylene, naphthylene, anthrylene, indenylene, fluorenylene, perylenylene, phenanthrylene, pyrenylene, fluoranthenylene or benzo[ghi]perylenylene.

[0015] The C 3 ~C 30 The heteroatom in the heteroaryl is selected from oxygen, sulfur or nitrogen.

[0016] The C 3 ~C 30 heteroaryl is selected from benzofuranyl, benzothienyl, pyridyl, dibenzofuranyl, pyrimidinyl, dibenzothienyl, carbazolyl, diarylamino, benzofurocarbazolyl, benzofurothienyl or triazinyl.

[0017] The C 3 ~C 30 heteroarylene is selected from benzofuran-1,1-diyl, benzothiophene-1,1-diyl, pyridine-1,1-diyl, dibenzofuran-1,1-diyl, pyrimidine-1,1-diyl, dibenzothiophene-1,1-diyl, carbazole-1,1-diyl, diarylamine-1,1-diyl, benzofurocarbazole-1,1-diyl, benzofurothiophene-1,1-diyl or triazine-1,1-diyl.

[0018] The following are the preferred technical solutions of the present invention, but do not limit the technical solutions provided by the present invention. Through the following preferred technical solutions, the objects and beneficial effects of the present invention can be better achieved and realized.

[0019] As a preferred technical solution of the present invention, the cyano-containing compound includes any one of the following compounds:

[0020]

[0021]

[0022] Preferably, the compound shown in Formula I is selected from any one of Compounds 1 to 12:

[0023]

[0024] The present invention lists some specific structural forms of the cyano-containing compound, but the cyano-containing compound described in the present invention is not limited to these listed chemical structures. Any structure based on the structure shown in Formula I, where R 1 , R 2 , and L1 meet the above-defined conditions should be included.

[0025] In a second aspect, the present invention provides an organic electroluminescent device, and the organic electroluminescent device includes the cyano-containing compound as described in the first aspect.

[0026] Preferably, the organic electroluminescent device includes a first electrode, a second electrode, and an organic layer disposed between the first electrode and the second electrode;

[0027] The material of the organic layer includes the cyano-containing compound as described in the first aspect.

[0028] Preferably, the organic layer includes an electron transport layer;

[0029] The material of the electron transport layer includes the cyano-containing compound as described in the first aspect.

[0030] In a third aspect, the present invention provides a display device, and the display device includes the organic electroluminescent device as described in the second aspect.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] By designing the structure of the cyano-containing compound, the obtained cyano-containing compound, as the material of the electron transport layer in the organic electroluminescent device, can effectively improve the current efficiency of the organic electroluminescent device and improve the lifespan of the organic electroluminescent device.

[0033] The cyano group-containing compound provided by the present invention has good electron-accepting ability, and introducing a bulky fluorene group can weaken the intermolecular interaction; when it is used as an electron transport material in an organic electroluminescent device, the current efficiency is improved, and at the same time, the lifetime of the device is also greatly improved. Detailed Embodiments

[0034] To facilitate the understanding of the present invention, preparation examples and embodiments are listed as follows. Those skilled in the art should understand that the preparation examples and embodiments are only for helping to understand the present invention and should not be regarded as specific limitations on the present invention.

[0035] Synthesis Example 1

[0036] This example provides a synthesis method of Compound 1, which is as follows:

[0037]

[0038] (1) Synthesis of Intermediate 1-a

[0039] 3-Bromo-6-chloro-9,9-diphenyl-9H-fluorene (100 mmol), phenylboronic acid (100 mmol), tetrakis(triphenylphosphine)palladium (1 mmol), potassium carbonate (120 mmol), 50 mL of water, and 300 mL of dioxane were added to a reaction flask, and the reaction was refluxed for 4 h under nitrogen protection. After the reaction was complete, the temperature was lowered, toluene was added, and liquid separation was performed. The organic layer was rotary evaporated to dryness, and the obtained solid was recrystallized with toluene to obtain Intermediate 1-a.

[0040] The mass spectrometry data of Intermediate 1-a was tested, and the measured mass spectrometry m / z was 428.13.

[0041] (2) Synthesis of Intermediate 1-b

[0042] Intermediate 1-a (40 mmol), bis(pinacolato)diboron (40 mmol), tris(dibenzylideneacetone)dipalladium (0.4 mmol), 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl (0.8 mmol), potassium acetate (60 mmol), and 300 mL of toluene were added to a reaction flask and heated to reflux for 8 h. The reaction was monitored by TLC until it was complete. After filtration through diatomaceous earth, it was washed with pure water until neutral, and the organic phase was concentrated. The obtained solid was recrystallized with a mixed solvent of toluene and ethanol to obtain Intermediate 1-b.

[0043] The mass spectrometry data of Intermediate 1-b was tested, and the measured mass spectrometry m / z was 520.26.

[0044] (3) Synthesis of Compound 1

[0045] Intermediate 1-b (30 mmol), 4-(4-chloro-6-phenyl-1,3,5-triazin-2-yl)benzonitrile (30 mmol), dichlorobis(tert-butyl)-(4-dimethylaminophenyl)phosphine palladium(II) (0.3 mmol), potassium carbonate (60 mmol), toluene (300 mL), and water (100 mL) were added to a reaction flask, heated to reflux for 12 h, monitored by TLC until the reaction was complete, cooled after the reaction was complete, separated by liquid-liquid extraction, the organic layer was evaporated to dryness, and the resulting solid was recrystallized from a mixed solvent of dichloromethane and ethanol to obtain Compound 1.

[0046] The mass spectrometry data of Compound 1 was tested, and the measured mass spectrometry m / z was 650.25.

[0047] Synthesis Example 2

[0048] Synthesis of Compound 2:

[0049]

[0050] Referring to the synthesis method of Compound 1, [4-chloro-6-(1,1'-biphenyl-4-yl)-1,3,5-triazin-2-yl]benzonitrile was used to replace 4-(4-chloro-6-phenyl-1,3,5-triazin-2-yl)benzonitrile in Synthesis Example 1, and Compound 2 could be obtained under the same other conditions.

[0051] The mass spectrometry data of Compound 2 was tested, and the measured mass spectrometry m / z was 726.28.

[0052] Synthesis Example 3

[0053] Synthesis of Compound 7:

[0054]

[0055] (1) Synthesis of Intermediate 7-a

[0056] 3-Bromo-6-chloro-9,9-diphenyl-9H-fluorene (100 mmol), 2-naphthaleneboronic acid (100 mmol), tetrakis(triphenylphosphine)palladium 1 mmol, potassium carbonate (120 mmol), water 50 mL, and dioxane 300 mL were added to a reaction flask, refluxed for 4 h under nitrogen protection, cooled after the reaction was complete, toluene was added, separated by liquid-liquid extraction, the organic layer was evaporated to dryness, and the resulting solid was recrystallized from a mixed solvent of toluene and ethanol to obtain Intermediate 7-a.

[0057] The mass spectrometry data of Intermediate 7-a was tested, and the measured mass spectrometry m / z was 478.15.

[0058] (2) Synthesis of Intermediate 7-b

[0059] Add intermediate 7-a (40 mmol), bis(pinacolato)diboron (40 mmol), tris(dibenzylideneacetone)dipalladium(0) (0.4 mmol), 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl (0.8 mmol), potassium acetate (60 mmol), and 300 mL of toluene into a reaction flask. Heat the mixture to reflux for 8 h. Monitor the reaction completion by TLC. After filtration through diatomaceous earth, wash with pure water until neutral. Concentrate the organic phase. Recrystallize the obtained solid with a mixed solvent of toluene and ethanol to obtain intermediate 7-b.

[0060] Test the mass spectrometry data of intermediate 7-b, and the measured mass spectrometry m / z: 570.27.

[0061] (3) Synthesis of compound 7

[0062] Add intermediate 7-b (30 mmol), 4-(4-chloro-6-phenyl-1,3,5-triazin-2-yl)benzonitrile (30 mmol), dichloro(tert-butyl)bis(4-(dimethylamino)phenyl)phosphine palladium(II) (0.3 mmol), potassium carbonate (60 mmol), 300 mL of toluene, and 100 mL of water into a reaction flask. Heat the mixture to reflux for 12 h. Monitor the reaction completion by TLC. After the reaction is completed, cool down the temperature, separate the liquid, spin-dry the organic layer, and recrystallize the obtained solid with a mixed solvent of toluene and ethanol to obtain compound 7.

[0063] Test the mass spectrometry data of compound 7, and the measured mass spectrometry m / z: 700.26.

[0064] Synthesis Example 4

[0065] Synthesis of compound 9:

[0066]

[0067] Refer to the synthesis method of compound 1. Replace 4-(4-chloro-6-phenyl-1,3,5-triazin-2-yl)benzonitrile in Synthesis Example 1 with 4-[4-(4-chlorophenyl)-6-phenyl-1,3,5-triazin-2-yl]benzonitrile, and keep other conditions unchanged to obtain compound 9.

[0068] Test the mass spectrometry data of compound 9, and the measured mass spectrometry m / z: 726.28.

[0069] Synthesis Example 5

[0070] Synthesis of compound 10:

[0071]

[0072] Referring to the synthesis method of Compound 1, replace 4-(4-chloro-6-phenyl-1,3,5-triazin-2-yl)benzonitrile in Synthesis Example 1 with 4-{4-[4-(4-bromophenyl)phenyl]-6-phenyl-1,3,5-triazin-2-yl}benzonitrile, and Compound 10 can be obtained under the same other conditions.

[0073] Test the mass spectrometry data of Compound 10, and the measured mass spectrometry m / z: 802.31.

[0074] Synthesis Example 6

[0075] Synthesis of Compound 11:

[0076]

[0077] Referring to the synthesis method of Compound 1, replace 4-(4-chloro-6-phenyl-1,3,5-triazin-2-yl)benzonitrile in Synthesis Example 1 with 4-[4-(6-chloronaphthalen-2-yl)-6-phenyl-1,3,5-triazin-2-yl]benzonitrile, and Compound 11 can be obtained under the same other conditions.

[0078] Test the mass spectrometry data of Compound 11, and the measured mass spectrometry m / z: 776.29.

[0079] Synthesis Example 7

[0080] Synthesis of Compound 12:

[0081]

[0082] Referring to the synthesis method of Compound 1, replace 4-(4-chloro-6-phenyl-1,3,5-triazin-2-yl)benzonitrile in Synthesis Example 1 with 4-[4-(4-chloronaphthalen-1-yl)-6-phenyl-1,3,5-triazin-2-yl]benzonitrile, and Compound 12 can be obtained under the same other conditions.

[0083] Test the mass spectrometry data of Compound 12, and the measured mass spectrometry m / z: 776.29.

[0084] For compounds with unspecified specific synthesis steps, they can be prepared by combining the above examples with common general knowledge in the art.

[0085]

[0086]

[0087] Device Example 1

[0088] In the examples, the compounds of the present application were selected as the electron transport materials in the organic electroluminescent devices, and in the comparative examples, E1 - E3 were selected as the electron transport materials in the organic electroluminescent devices.

[0089] The structure of the organic electroluminescent device is as follows:

[0090] ITO / HT(40nm) / BH-1:BD-1 3% / Compound 1(30nm) / LiF(0.5nm) / Al(150nm).

[0091] The preparation method of the above organic electroluminescent device is as follows:

[0092] The glass substrate coated with the ITO transparent conductive layer (as the anode) was ultrasonically treated in a cleaning agent, then rinsed in deionized water, ultrasonically degreased in a mixed solvent of acetone and ethanol, baked in a clean environment until completely dehydrated, cleaned with ultraviolet light and ozone, and bombarded with a low-energy cation beam on the surface to improve the surface properties and enhance the bonding ability with the hole injection layer;

[0093] The above glass substrate was placed in a vacuum chamber, evacuated to 1×10 -5 ~9×10 -3 Pa, and HT was vacuum-evaporated on the anode as the hole transport layer at a deposition rate of 0.1nm / s, and the deposited film thickness was 40nm;

[0094] The light-emitting layer was vacuum-evaporated on the hole transport layer at a deposition rate of 0.1nm / s, and the total deposited film thickness was 30nm. The host material of the light-emitting layer was BH-1, and the doping material was BD-1. 3% refers to the doping ratio of the doping material, that is, the volume ratio of the host material to the doping material in the light-emitting layer is 97:3.

[0095] The glass substrate on which the light-emitting layer had been deposited in the previous step was transferred to the vacuum chamber, and Compound 1 provided in this patent was vacuum-evaporated on the light-emitting layer as the electron transport layer of the electron transport material at a deposition rate of 0.1nm / s, and the total deposited film thickness was 30nm; 0.5nm of LiF and 150nm of Al were vacuum-evaporated on the electron transport layer as the electron injection layer and the cathode. The brightness, current efficiency, and lifetime of the prepared organic electroluminescent device were measured.

[0096] Device Examples 2 - 7

[0097] Device Examples 2 - 7 respectively provide an organic electroluminescent device. The difference from Device Example 1 is only that the electron transport materials are different (see Table 1 below), and other conditions are the same as those in Device Example 1.

[0098] Device Comparative Examples 1 - 3

[0099] Device Comparative Examples 1 to 3 respectively provide an organic electroluminescent device, which is different from Device Example 1 only in that the electron transport material is different (see Table 1 below), and other conditions are the same as those in Device Example 1.

[0100] Performance Test

[0101] Test method: Test the current efficiency and lifetime LT90 of the above-provided OLED devices; among them, LT90 refers to the time required for the current density to remain unchanged while maintaining the initial brightness of 1000 nit and the brightness to drop to 90% of the original brightness. The test items include the brightness, current efficiency, and lifetime LT90 of the organic electroluminescent device. The current efficiency and LT90 data are relative values at a brightness of 1000 cd / m 2 (based on Comparative Example 1). The performance test results of the organic electroluminescent device are shown in Table 1 below:

[0102] Table 1

[0103]

[0104] It can be seen from the content of Table 1 that the present invention obtains a cyanide-containing compound through molecular design. The cyanide-containing compound provided by the present invention can be used as an electron transport material for OLED light-emitting devices, enabling the OLED light-emitting devices to have higher current efficiency and longer lifetime.

[0105] The present invention uses the above examples to illustrate the detailed process flow of the present invention, but the present invention is not limited to the above detailed process flow, that is, it does not mean that the present invention must rely on the above detailed process flow to be implemented. Those skilled in the art should understand that any improvement to the present invention, the equivalent substitution of each raw material of the product of the present invention, the addition of auxiliary components, and the selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A cyano compound, characterized in that The cyano compound has a structure as shown in Formula I: The R1 and R2 are independently selected from C1 to C 12 Alkyl, C6~C 30 Aryl or C3~C 30 Any of the heteroaryl groups; L1 is selected from C6~C 30 Arylene or C3~C 30 Any of the heteroarylene groups; n is an integer selected from 0-1.

2. The cyano compound according to claim 1, characterized in that The C1~C 12 The alkyl group is selected from methyl, ethyl, propyl, isopropyl, butyl, tert-butyl, pentyl, tert-pentyl, n-hexyl or cyclohexyl.

3. The cyano compound according to claim 1, characterized in that The C6~C 30 Aryl is selected from phenyl, biphenyl, terphenyl, naphthyl, anthracenyl, indenylfluorenyl, perylenyl, phenanthrenyl, pyrenyl, fluoranthenyl or triphenylenyl.

4. The cyano compound according to claim 1, characterized in that The C3~C 30 The heteroaryl group is selected from benzofuranyl, benzothiophenyl, pyridyl, dibenzofuranyl, pyrimidinyl, dibenzothiophenyl, carbazolyl, diarylideneamine, benzofuranocarbazolyl, benzofuranothiophenyl or triazine.

5. The cyano compound according to claim 1, characterized in that The C6~C 30 The arylene group is selected from phenylene, biphenylene, terphenylene, naphthylene, anthracene, indenylene, fluorenylene, perylene, phenanthrenylene, pyrenylene, fluoranthenylene or triphenylene.

6. The cyano compound according to claim 1, characterized in that The C3~C 30 The heteroarylene group is selected from benzofuranylene, benzothiophenylene, pyridylene, dibenzofuranylene, pyrimidylene, dibenzothiophenylene, carbazolylene, diaryleneamino group, benzofuranocarbazolylene, benzofuranothiophenylene or triazinylene.

7. The cyano group-containing compound according to any one of claims 1 to 6, characterized in that The cyano compound is selected from any one of the following compounds:

8. An organic electroluminescent device, characterized in that: The organic electroluminescent device comprises the cyano compound according to any one of claims 1 to 7.

9. The organic electroluminescent device according to claim 8, characterized in that: The organic electroluminescent device comprises a first electrode, a second electrode and an organic layer disposed between the first electrode and the second electrode; the organic layer comprises an electron transport layer; and the material of the electron transport layer comprises the cyanide-containing compound according to any one of claims 1 to 7.

10. A display device, characterized in that: The display device comprises the organic electroluminescent device according to any one of claims 8 to 9.

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