Compound containing dicarbazole and triazine group and application thereof

Abstract

The invention provides a compound containing dicarbazole and triazine groups and application of the compound. The compound containing the dicarbazole and the triazine group has a structure as shown in a formula I. By designing the structure of the compound containing the dicarbazole and the triazine group, the obtained compound containing the dicarbazole and the triazine group has excellent performance, and an organic electroluminescent device prepared by taking the compound as an electron transport material has relatively low driving voltage and relatively high current efficiency.

Description

Technical Field

[0001] The invention belongs to the field of organic photoelectric technology, and in particular relates to a compound containing a dicarbazole and a triazine group and application thereof. Background Art

[0002] Organic Light-Emitting Diode (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, and good flexibility. It can meet consumers' new demands 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 fluorescent material is made to emit light by utilizing the recombination energy of holes injected from the anode and electrons injected from the cathode. It has the following structure: an anode, a cathode, and an organic material layer between the two. 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 generate light with a specific wavelength when they migrate to the ground state. Among them, the hole transport layer can change the hole transfer efficiency, light-emitting efficiency, life, etc. of holes to the light-emitting layer.

[0004] At present, the research on organic electroluminescent materials has been widely carried out in academia and industry. Among them, luminescent materials are an important component of organic electroluminescent devices. The transmission performance and luminous efficiency of luminescent materials restrict the industrialization of luminescent devices. Therefore, designing and finding a compound as a new OLED material to overcome its shortcomings in practical applications is the focus of OLED material research and the future research and development trend. Summary of the invention

[0005] In view of the shortcomings of the prior art, the object of the present invention is to provide a compound containing a biscarbazole and triazine group and its application. The present invention is designed through the structure of the compound containing a biscarbazole and triazine group, and the obtained compound containing a biscarbazole and triazine group has excellent performance and is suitable for use as an electron transport material in an organic electroluminescent device.

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

[0007] In a first aspect, the present invention provides a compound containing a biscarbazole and a triazine group, wherein the compound containing a biscarbazole and a triazine group has a structure as shown in Formula I:

[0008]

[0009] Wherein, R1, R2 and R3 are independently selected from substituted or unsubstituted C1 to C 12 Alkyl, C6~C 30 Aromatic hydrocarbon or C3~C 30 Any one of the aromatic heterocyclic groups;

[0010] When the substituted or unsubstituted group contains a substituent, the substituent is selected from C1 to C 12 Alkyl, C6~C 30 Aromatic hydrocarbon or C3~C 30 An aromatic heterocyclic group;

[0011] L1 is a single bond.

[0012] Preferably, the C1 to C 12 The alkyl groups are independently selected from methyl, ethyl, propyl, isopropyl, butyl, tert-butyl, pentyl, tert-pentyl, n-hexyl or cyclohexyl.

[0013] Preferably, the C6~C 30 The aromatic hydrocarbon group is selected from phenyl, biphenyl, terphenyl, naphthyl, anthracenyl, indenylfluorenyl, perylenyl, phenanthrenyl, pyrenyl, fluoranthenyl or triphenylenyl.

[0014] Preferably, the C3 to C 30 The heteroatom in the aromatic heterocyclic group is selected from oxygen, sulfur and nitrogen.

[0015] Preferably, the C3 to C 30 The aromatic heterocyclic group is selected from any one of benzofuran, benzothiophene, pyridine, dibenzofuran, pyrimidine, dibenzothiophene, carbazole, diarylideneamine, benzofuranocarbazole, benzofuranothiophene and triazine.

[0016] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. Through the following preferred technical solutions, the objectives and beneficial effects of the present invention can be better achieved and realized.

[0017] Preferably, the compound containing biscarbazole and triazine groups includes any one of the following compounds:

[0018]

[0019]

[0020]

[0021] More preferably, the compound represented by formula I is selected from any one of compounds 1 to 12:

[0022]

[0023] The present invention lists some specific structural forms of the compounds containing biscarbazole and triazine groups, but the compounds containing biscarbazole and triazine groups in the present invention are not limited to these listed chemical structures. All structures based on the structure shown in Formula I and in which R1, R2, R3, and L1 meet the above-mentioned limiting conditions should be included.

[0024] In a second aspect, the present invention provides an organic electroluminescent device, wherein the organic electroluminescent device comprises the compound containing biscarbazole and triazine groups as described in the first aspect.

[0025] Preferably, the organic electroluminescent device comprises a first electrode, a second electrode and an organic layer disposed between the first electrode and the second electrode;

[0026] The material of the organic layer includes the compound containing biscarbazole and triazine groups as described in the first aspect.

[0027] Preferably, the organic layer comprises an electron transport layer;

[0028] The material of the electron transport layer includes the compound containing biscarbazole and triazine groups as described in the first aspect.

[0029] In a third aspect, the present invention provides a display device, comprising the organic electroluminescent device as described in the second aspect.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] The present invention designs the structure of the compound containing biscarbazole and triazine groups to obtain the compound containing biscarbazole and triazine groups, which has good electron transport performance and can be used to prepare organic electroluminescent devices, especially as an electron transport layer material in the organic electroluminescent device, and can effectively reduce the driving voltage of the organic electroluminescent device and improve the current efficiency of the organic electroluminescent device. DETAILED DESCRIPTION

[0032] For the convenience of understanding the present invention, the present invention lists the preparation examples and embodiments as follows. It should be understood by those skilled in the art that the preparation examples and embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0033] Synthesis Example 1

[0034] This embodiment provides a method for synthesizing compound 1, as described below:

[0035]

[0036] (1) Synthesis of Intermediate I

[0037] 10-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-11H-benzo[a]carbazole (0.1 mol), o-bromonitrobenzene (0.11 mmol), tetrakis(triphenylphosphine)palladium (3 mmol), potassium carbonate (0.15 mol), 300 mL of toluene, 100 mL of ethanol, and 100 mL of water were added to a reaction bottle, and reacted at 85°C for 6 h under nitrogen protection. After the reaction was completed, the temperature was lowered to 50°C, 200 ml of ethanol was added, and the mixture was stirred in a water bath for 30 min. The mixture was filtered, 500 ml of water was added to the filter cake, and the mixture was stirred for 30 min. The mixture was filtered, 500 ml of ethanol was added to the filter cake, and the mixture was stirred for 30 min. The mixture was filtered, and the filter cake was recrystallized from toluene and ethanol to obtain intermediate I.

[0038] The intermediate I was subjected to mass spectrometry test, and the mass spectrum m / z was measured to be 338.11.

[0039] (2) Synthesis of Intermediate II

[0040] Intermediate I (40 mmol), bromobenzene (40 mmol), cuprous iodide (40 mmol), o-phenanthroline (80 mmol), potassium phosphate (60 mmol), and 300 mL of dimethyl sulfoxide were added into a reaction flask and heated to 150° C. for 12 h. The reaction was completed after TLC monitoring. After diatomaceous earth filtration, water was added to precipitate the solid, which was filtered with suction. The filter cake was purified by recrystallization with toluene and ethanol, and intermediate II was obtained by suction filtration.

[0041] The mass spectrometry test of intermediate II showed a mass spectrum of m / z: 414.14.

[0042] (3) Synthesis of Intermediate III

[0043] Intermediate II (0.1 mol), triphenylphosphine (0.2 mol) and 300 mL of o-dichlorobenzene were added to a reaction flask, and the reaction was refluxed for 6 h under nitrogen protection. After the reaction was complete, o-dichlorobenzene was distilled off under reduced pressure, and the product in the flask was dissolved with 500 ml of tetrahydrofuran, 100 g of silica gel was added, and the organic solvent was dried with a rotary evaporator. The sample was mixed and passed through a chromatography column, and the column liquid was concentrated to purify the intermediate III.

[0044] The mass spectrometry test of intermediate III showed a mass spectrum of m / z: 382.15.

[0045] (4) Synthesis of Compound 1

[0046] Intermediate III (0.5 mol), 2-chloro-4,6-diphenyl-1,3,5-triazine (0.5 mol), tris(dibenzylideneacetone)dipalladium (0.01 mol), 2-dicyclohexylphosphine-2',4',6'-triisopropylbiphenyl (0.02 mol), sodium tert-butoxide (0.75 mol) and xylene (300 mL) were added to a reaction bottle, heated to reflux, and reacted for 12 h. The reaction was completed after TLC monitoring. 300 ml of n-heptane was added to the reaction solution, stirred for 30 min and filtered. The filter cake was washed twice with water and once with ethanol, and then recrystallized from toluene and ethanol to obtain compound 1.

[0047] Compound 1 was subjected to mass spectrometry test, and the mass spectrum m / z was measured to be 613.23.

[0048] Synthesis Example 2

[0049] This embodiment provides a method for synthesizing compound 2, as described below:

[0050]

[0051] Referring to the synthesis method of Synthesis Example 1, 2,4-di([1,1'-biphenyl]-4-yl)-6-chloro-1,3,5-triazine is used to replace the 2-chloro-4,6-diphenyl-1,3,5-triazine in Synthesis Example 1, and other conditions remain unchanged to obtain Compound 2.

[0052] The mass spectrometry test of compound 2 showed that the mass spectrum m / z was 765.29.

[0053] Synthesis Example 3

[0054] This embodiment provides a method for synthesizing compound 3, as described below:

[0055]

[0056] (1) Synthesis of Intermediate IV

[0057] Referring to the synthesis method of intermediate II, bromobenzene is replaced by 4-bromobiphenyl and other conditions remain unchanged to obtain intermediate IV.

[0058] The mass spectrometry test of intermediate IV showed a mass spectrum of m / z: 490.17.

[0059] (2) Synthesis of intermediate V

[0060] Referring to the synthesis method of intermediate III, intermediate IV is used to replace intermediate II, and intermediate V can be obtained while keeping other conditions unchanged.

[0061] The intermediate V was subjected to mass spectrometry test, and the mass spectrum m / z was measured to be 458.18.

[0062] (3) Synthesis of Compound 3

[0063] Referring to the synthesis method of compound 1, intermediate V is used to replace intermediate III, 2-([1,1'-biphenyl]-4-yl)-4-chloro-6-phenyl-1,3,5-triazine is used to replace 2-chloro-4,6-diphenyl-1,3,5-triazine, and other conditions remain unchanged to obtain compound 3.

[0064] Compound 3 was subjected to mass spectrometry test, and the mass spectrum m / z was measured to be 765.29.

[0065] Synthesis Example 4

[0066] This embodiment provides a method for synthesizing compound 4, as described below:

[0067]

[0068] (1) Synthesis of intermediate VI

[0069] Referring to the synthesis method of intermediate II, 3-bromodibenzo[b,d]thiophene is used instead of bromobenzene, and other conditions remain unchanged to obtain intermediate VI.

[0070] The intermediate VI was subjected to mass spectrometry test, and the mass spectrum m / z was measured to be 520.12.

[0071] (2) Synthesis of intermediate VII

[0072] Referring to the synthesis method of intermediate III, intermediate VII can be obtained by replacing intermediate II with intermediate VI while keeping other conditions unchanged.

[0073] The intermediate VII was subjected to mass spectrometry test, and the mass spectrum m / z was measured to be 488.13.

[0074] (3) Synthesis of Compound 4

[0075] Referring to the synthesis method of compound 1, intermediate VII is used to replace intermediate III, 2,4-di([1,1'-biphenyl]-4-yl)-6-chloro-1,3,5-triazine is used to replace 2-chloro-4,6-diphenyl-1,3,5-triazine, and other conditions remain unchanged to obtain compound 4.

[0076] Compound 4 was subjected to mass spectrometry test, and the mass spectrum m / z was measured to be 871.28.

[0077] Other compounds whose specific synthesis steps are not listed can be prepared by common knowledge in the art in combination with the above embodiments.

[0078] The specific structures of the compounds used in the device embodiments and device comparative examples of the present invention are shown below:

[0079]

[0080] In the following device examples, the compound containing biscarbazole and triazine groups provided by the present invention is selected as the electron transport material in the organic electroluminescent device, and the device comparative examples select the above E1 to E3 as the electron transport material in the organic electroluminescent device.

[0081] Device Example 1

[0082] The device embodiment provides an organic electroluminescent device, in which the compound 1 provided in Synthesis Example 1 of the present invention is used as an electron transport layer material in the organic electroluminescent device.

[0083] The structure of the organic electroluminescent device is: ITO / NPB (40 nm) / EM1 (30 nm) / Compound 1 (30 nm) / LiF (0.5 nm) / Al (150 nm).

[0084] The preparation process of organic electroluminescent device is as follows:

[0085] The glass substrate coated with an ITO transparent conductive layer (as an anode) is 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 the water is completely removed, cleaned with ultraviolet light and ozone, and bombarded with a low-energy cation beam to improve the properties of the surface and enhance the binding ability with the hole injection layer;

[0086] The glass substrate was placed in a vacuum chamber and evacuated to 1×10 -5 ~9×10 -3 Pa, vacuum evaporate NPB on the anode as a hole transport layer, the evaporation rate is 0.1nm / s, and the evaporation film thickness is 40nm;

[0087] Vacuum evaporate EM1 on the hole transport layer as the organic light-emitting layer of the device, with an evaporation rate of 0.1 nm / s and a total evaporation film thickness of 30 nm;

[0088] Compound 1 is vacuum-deposited on the organic light-emitting layer as an electron transport layer of the organic electroluminescent device; the evaporation rate is 0.1 nm / s, and the total evaporation film thickness is 30 nm;

[0089] 0.5 nm of LiF and 150 nm of Al were vacuum-deposited on the electron transport layer to serve as an electron injection layer and a cathode.

[0090] Device Examples 2 to 13

[0091] Device Examples 2 to 13 respectively provide an organic electroluminescent device, which is different from Device Example 1 only in that the electron transport layer material is different (see Table 1 for details), and other conditions are the same as those of Device Example 1.

[0092] Device Comparison Examples 1 to 3

[0093] 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 layer material is different (see Table 1 for details), and other conditions are the same as those of Device Example 1.

[0094] Performance Testing

[0095] Test the driving voltage, current efficiency and life LT90 of the OLED devices provided above; LT90 refers to the time required for the brightness to drop to 90% of the original brightness while maintaining the current density at the initial brightness of 1000nit. The test items include the brightness, driving voltage and current efficiency of the organic electroluminescent device. The driving voltage, current efficiency and LT90 data are all based on a brightness of 1000cd / m 2 The relative value of the device performance test results is shown in Table 1:

[0096] Table 1

[0097]

[0098]

[0099] It can be seen from the contents of Table 1 that the present invention obtains a compound containing a biscarbazole and a triazine group through molecular design. The compound containing a biscarbazole and a triazine group provided by the present invention can be used as an electron transport material for an OLED light-emitting device, so that the OLED light-emitting device has a lower driving voltage, a higher current efficiency and a longer life.

[0100] The present invention illustrates the detailed process flow of the present invention through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned detailed process flow, that is, it does not mean that the present invention must rely on the above-mentioned detailed process flow to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of various raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A compound containing a biscarbazole and a triazine group, characterized in that: Having the structure shown in Formula I: Wherein, R1, R2 and R3 are independently selected from substituted or unsubstituted C1 to C 12 Alkyl, C6~C 30 Aromatic hydrocarbon or C3~C 30 Any one of the aromatic heterocyclic groups; When the substituted or unsubstituted group contains a substituent, the substituent is selected from C1 to C 12 Alkyl, C6~C 30 Aromatic hydrocarbon or C3~C 30 An aromatic heterocyclic group; L1 is a single bond.

2. The compound containing biscarbazole and triazine groups according to claim 1, characterized in that C1~C 12 The alkyl groups are independently selected from methyl, ethyl, propyl, isopropyl, butyl, tert-butyl, pentyl, tert-pentyl, n-hexyl or cyclohexyl; the C6-C 30 The aromatic hydrocarbon group is selected from phenyl, biphenyl, terphenyl, naphthyl, anthracenyl, indenyl, fluorenyl, perylenyl, phenanthryl, pyrenyl, fluoranthenyl or triphenylenyl.

3. The compound containing biscarbazole and triazine groups according to claim 1, characterized in that C3~C 30 The heteroatom in the aromatic heterocyclic group is selected from oxygen, sulfur and nitrogen.

4. The compound containing biscarbazole and triazine groups according to claim 3, characterized in that C3~C 30 The aromatic heterocyclic group is selected from any one of benzofuran, benzothiophene, pyridine, dibenzofuran, pyrimidine, dibenzothiophene, carbazole, diarylideneamine, benzofuranocarbazole, benzofuranothiophene and triazine.

5. The compound containing biscarbazole and triazine groups according to any one of claims 1 to 4, characterized in that: The compound containing biscarbazole and triazine groups includes any one of the following compounds:

6. An organic electroluminescent device, characterized in that: The organic electroluminescent device comprises the compound containing biscarbazole and triazine groups as claimed in any one of claims 1 to 5.

7. The organic electroluminescent device according to claim 6, 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; the material of the electron transport layer comprises the compound containing bicarbazole and triazine groups as claimed in any one of claims 1 to 5.

8. A display device, characterized in that: The display device comprises the organic electroluminescent device according to any one of claims 6 to 7.

Images