A heterocyclic compound and application thereof

Abstract

The application provides a heterocyclic compound and application thereof, and relates to the technical field of organic photoelectricity. The heterocyclic compound in the application can be used as an electron transport layer material in an organic electroluminescent device, and can effectively reduce the driving voltage of the organic electroluminescent device, improve the current efficiency of the organic electroluminescent device, and improve the service life of the organic electroluminescent device.

Description

Technical Field

[0001] This invention belongs to the field of organic optoelectronic technology, specifically relating to the field of organic optoelectronic materials, and more specifically to a heterocyclic compound and its applications. Background Technology

[0002] Organic light-emitting diodes (OLEDs) have advantages such as light weight, small size, wide viewing angle, fast response, wide operating temperature range, low energy consumption, high efficiency, good color purity, high definition, and good flexibility. They can meet consumers' new demands for display technology and have a promising application prospect in the fields of lighting and display.

[0003] Organic light-emitting diodes (OLEDs) are self-emissive devices that utilize the principle that fluorescent materials emit light by recombination of holes injected from the anode and electrons injected from the cathode when an electric field is applied. They have the following structure: an anode, a cathode, and an organic layer between them. To improve the efficiency and stability of OLEDs, the organic layer typically comprises multiple functional layers made of different materials, such as a hole injection layer (HIL), a hole transport layer (HTL), an emissive layer, an electron transport layer (ETL), and an electron injection layer (EIL). In such OLEDs, when a voltage is applied between the anode and cathode, holes from the anode and electrons from the cathode are injected into the organic material layer, and the resulting excitons migrate to the ground state, producing light with a specific wavelength.

[0004] Currently, research on organic electroluminescent materials has been widely carried out in academia and industry. Designing and searching for a compound as a new OLED material to overcome its shortcomings in practical applications is the focus of OLED material research and a future development trend. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this invention is to provide a heterocyclic compound and its application.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a heterocyclic compound having the structure shown in Formula I:

[0008]

[0009] In Formula I, R1 and R2 are each independently selected from substituted or unsubstituted C6 to C6. 30 Aryl, substituted or unsubstituted C3-C 30 Any one of the heteroaryl groups;

[0010] The substituents are each independently selected from cyano, C1-C1 groups. 12 Alkyl, C6-C 30 Aryl, C3~C 30 Any one of the heteroaryl groups;

[0011] L1 is selected from C6~C 30 aryl or C3~C 30 Any of the heteroaryl groups;

[0012] n is an integer selected from 0 to 1.

[0013] The heterocyclic compounds provided by this invention have specific molecular structures and spatial configurations, which endow them with excellent electron transport properties and film-forming properties, making the electron transport layer more compact, which is conducive to the transport of charge carriers, reducing the device driving voltage, promoting the improvement of device efficiency, extending the device's service life, and comprehensively improving the overall performance of organic electroluminescent devices.

[0014] Preferably, C6~C 30 The aryl group is selected from phenyl, biphenyl, terphenyl, naphthyl, anthracene, indyl, fluorenyl, perylene, phenanthryl, pyrene, fluoranyl or benzophenanthryl.

[0015] Preferably, C3 to C 30 The heteroatom in a heteroaryl group is selected from an oxygen atom, a sulfur atom, or a nitrogen atom.

[0016] Preferably, C3 to C 30 The heteroaryl group is selected from benzofuranyl, benzothiophene, pyridyl, dibenzofuranyl, pyrimidinyl, dibenzothiophene, carbazoyl, N-phenylcarbazoyl, benzofuranocarbazoyl, benzofuranothiophene, or triazine.

[0017] Preferably, C6~C 30 The arylene group is selected from phenylene, biphenylene, terphenylene, naphthylene, anthracene, indene, fluorene, perylene, phenanthrene, pyrene, fluoranthylene, or benzophenanthrene.

[0018] Preferably, C3 to C 30 The heteroatom in a heteroaryl group is selected from oxygen, sulfur, or nitrogen atoms.

[0019] Preferably, C3 to C 30 The heteroaryl group is selected from benzofuranyl, benzothiophene, pyridinyl, dibenzofuranyl, pyrimidinyl, dibenzothiophene, carbazoyl, N-phenylcarbazoyl, benzofuranocarbazoyl, benzofuranothiophene, or triazineyl.

[0020] Preferably, the heterocyclic compound is selected from any one of the following compounds:

[0021]

[0022]

[0023] Preferably, the heterocyclic compound is selected from any one of compounds 1 to 12 below:

[0024]

[0025] This invention lists some specific structural forms of the heterocyclic compounds, but the heterocyclic compounds described in this invention are not limited to these listed chemical structures. Any structure based on the structure shown in Formula I, where L1, R1, and R2 satisfy the above-mentioned limiting conditions should be included.

[0026] In a second aspect, the present invention provides the application of heterocyclic compounds as described in the first aspect as electron transport materials for organic electroluminescent devices.

[0027] Thirdly, the present invention provides an organic electroluminescent device, the organic electroluminescent device comprising the heterocyclic compounds as described in the first aspect.

[0028] 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;

[0029] The organic layer includes heterocyclic compounds as described in the first aspect.

[0030] Preferably, the organic layer includes an electron transport layer, which includes a heterocyclic compound as described in the first aspect.

[0031] Fourthly, the present invention provides a display device comprising the organic electroluminescent device as described in the third aspect.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] The heterocyclic compounds of the present invention, as electron transport layer materials in organic electroluminescent devices, can effectively reduce the driving voltage of organic electroluminescent devices, improve the current efficiency of organic electroluminescent devices, and improve the lifetime of organic electroluminescent devices. Detailed Implementation

[0034] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be construed as limiting the scope of the invention.

[0035] Synthesis Example 1

[0036] This embodiment provides a method for synthesizing compound 1, the method of which is as follows:

[0037]

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

[0039] 60 mmol of starting material 1-a, 60 mmol of pinacol diborate, 0.6 mmol of tris(dibenzylacetone)palladium, 1.2 mmol of 2-dicyclohexylphosphine-2,4,6-triisopropylbiphenyl, 90 mmol of potassium carbonate, and 500 mL of toluene were added to a reaction flask and heated to reflux for 8 h. The reaction was monitored by thin-layer chromatography (TLC) until complete. After filtration with diatomaceous earth, the mixture was washed with purified water until neutral. The organic phase was concentrated under reduced pressure, and the resulting solid was recrystallized from a mixed solvent of toluene and ethanol to obtain intermediate 1-a.

[0040] The mass spectrometry data of intermediate 1-a were tested, and the mass spectrometry m / z was measured to be 411.16.

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

[0042] 60 mmol of intermediate 1-a, 60 mmol of 2-chloro-6-bromobenzaldehyde, 75 mmol of potassium carbonate, 3 mmol of tetra(triphenylphosphine)palladium, 150 mL of water, and 1000 mL of dioxane were added to a reaction flask and heated to reflux for 5 h. The reaction was monitored by TLC until complete. Water and dichloromethane were added for extraction, and the mixture was separated into liquid and liquid phases. The organic phase was then concentrated to obtain a solid. The solid was recrystallized from the solid using a mixed solvent of toluene and ethanol to obtain intermediate 1-b.

[0043] The mass spectrometry data of intermediate 1-b were tested, and the mass spectrometry m / z was measured to be 423.07.

[0044] (3) Synthesis of intermediate 1-c

[0045] 50 mmol of intermediate 1-b and 50 mmol of (methoxymethyl)triphenylphosphonium chloride were added to 500 mL of tetrahydrofuran. The mixture was cooled to 0 °C, and 60 mmol of potassium tert-butoxide was slowly added. The mixture was kept at this temperature for 30 min, and then slowly heated to room temperature. The reaction was carried out at room temperature for 4 h. The reaction was monitored by TLC until it was complete. After quenching with an aqueous solution of ammonium chloride, the mixture was extracted with ethyl acetate. The mixture was separated into liquid and liquid phases, and the organic phase was concentrated to obtain a solid. The solid was recrystallized from toluene to obtain intermediate 1-c.

[0046] The mass spectrometry data of intermediate 1-c were tested, and the mass spectrometry m / z was measured to be 451.10.

[0047] (4) Synthesis of intermediate 1-d

[0048] 40 mmol of intermediate 1-c was added to 500 mL of dichloromethane. After cooling to 0 °C, 80 mmol of methanesulfonic acid was added dropwise to the system. After the addition was complete, the temperature was slowly raised to room temperature and reacted at room temperature for 4 h. The reaction was monitored by TLC until it was complete. Water and dichloromethane were added for extraction, and the mixture was separated. The organic phase was then concentrated to obtain a solid. The solid was recrystallized from dichloromethane to obtain intermediate 1-d.

[0049] The mass spectrometry data of intermediate 1-d were tested, and the mass spectrometry m / z was measured to be 419.07.

[0050] (5) Synthesis of intermediate 1-e

[0051] 40 mmol of intermediate 1-d, 40 mmol of pinacol diborate, 0.4 mmol of tris(dibenzylacetone)palladium, 0.8 mmol of 2-dicyclohexylphosphine-2,4,6-triisopropylbiphenyl, 60 mmol of potassium carbonate, and 500 mL of toluene were added to a reaction flask and heated to reflux for 8 h. The reaction was monitored by TLC until complete. After filtration with diatomaceous earth, the mixture was washed with purified water until neutral. The organic phase was concentrated under reduced pressure, and the resulting solid was recrystallized from a mixed solvent of toluene and ethanol to obtain intermediate 1-e.

[0052] The mass spectrometry data of intermediate 1-e were tested, and the mass spectrometry m / z was measured to be 511.20.

[0053] (6) Synthesis of Compound 1

[0054] Intermediate 1-e 30 mmol, starting material 1-b 30 mmol, dichlorodi-tert-butyl-(4-dimethylaminophenyl)phosphine palladium(II) 3 mmol, potassium carbonate 36 mmol, and toluene 500 mL were added to a reaction flask and heated to reflux for 8 h. The reaction was monitored by TLC until complete. After cooling to room temperature, the solid was obtained by filtration. The solid was washed with water and methanol, dried, and then separated by silica gel column chromatography. The eluent was prepared by petroleum ether:ethyl acetate:dichloromethane = 5:1:2 (volume ratio) to obtain compound 1.

[0055] The mass spectrometry data of compound 1 were tested, and the mass spectrum m / z was measured to be 616.19.

[0056] Synthesis Example 2

[0057] Synthesis of compound 4:

[0058]

[0059] Following the same synthesis method as compound 1, compound 4 was obtained by replacing raw material 1-b in synthesis example 1 with raw material 4-b, while keeping other conditions unchanged.

[0060] The mass spectrometry data of compound 4 were tested, and the mass spectrum m / z was measured to be 617.19.

[0061] Synthesis Example 3

[0062] Synthesis of compound 5:

[0063]

[0064] Following the synthesis method of compound 1, compound 5 was obtained by replacing raw material 1-b in synthesis example 1 with raw material 5-b, while keeping other conditions unchanged.

[0065] The mass spectrometry data of compound 5 were tested, and the mass spectrum m / z was measured to be 742.24.

[0066] Synthesis Example 4

[0067] Synthesis of compound 7:

[0068]

[0069] Following the synthesis method of compound 1, compound 7 was obtained by replacing raw material 1-b in synthesis example 1 with raw material 7-b, while keeping other conditions unchanged.

[0070] The mass spectrometry data of compound 7 were tested, and the mass spectrum m / z was measured to be 644.22.

[0071] Synthesis Example 5

[0072] Synthesis of compound 9:

[0073]

[0074] Following the synthesis method of compound 1, compound 9 was obtained by replacing raw material 1-b in synthesis example 1 with raw material 9-b, while keeping other conditions unchanged.

[0075] The mass spectrometry data of compound 9 were tested, and the mass spectrum m / z was measured to be 732.25.

[0076] Synthesis Example 6

[0077] Synthesis of compound 11:

[0078]

[0079] Following the synthesis method of compound 1, compound 11 was obtained by replacing raw material 1-b in synthesis example 1 with raw material 11-b, while keeping other conditions unchanged.

[0080] The mass spectrometry data of compound 11 were tested, and the mass spectrum m / z was measured to be 768.25.

[0081] Synthesis Example 7

[0082] Synthesis of compound 12:

[0083]

[0084] Following the synthesis method of compound 1, compound 12 was obtained by replacing raw material 1-b in synthesis example 1 with raw material 12-b, while keeping other conditions unchanged.

[0085] The mass spectrometry data of compound 12 were tested, and the mass spectrometry m / z was measured to be 717.22.

[0086] Other compounds for which specific synthesis steps are not listed can be prepared using common knowledge in the art, in conjunction with the above examples.

[0087] The specific structures of some of the compounds used in the following device embodiments and device comparative examples are shown below:

[0088]

[0089] The device embodiments use compounds from this application as electron transport materials in organic electroluminescent devices, while the device comparative examples use E1 to E3 as electron transport materials in organic electroluminescent devices.

[0090] Device Example 1

[0091] The structure of the organic electroluminescent device is: ITO / HT (40nm) / BH-1:BD-13% (30nm) / Compound 1 (30nm) / LiF (0.5nm) / Al (150nm).

[0092] The fabrication method of the above-mentioned organic electroluminescent device is as follows:

[0093] The glass substrate coated with an ITO transparent conductive layer (as the anode) was ultrasonically treated in a cleaning agent, then rinsed in deionized water, then ultrasonically degreased in a mixed solvent of acetone and ethanol, then baked in a clean environment until completely dehydrated, cleaned with ultraviolet light and ozone, and bombarded with a low-energy cation beam to improve the surface properties and enhance the bonding ability with the hole injection layer.

[0094] The glass substrate was placed in a vacuum chamber and evacuated to a vacuum level of 1×10⁻⁶. -5 ~1×10 -6 Pa, HT is vacuum-deposited on the anode as a hole transport layer at a deposition rate of 0.1 nm / s and a film thickness of 40 nm;

[0095] A light-emitting layer is vacuum-deposited on top of the hole transport layer at a deposition rate of 0.1 nm / s and a film thickness of 30 nm. The main material of the light-emitting layer is BH-1, and the doping material is BD-1. The 3% refers to the doping ratio of the doping material, that is, the volume ratio of the main material of the light-emitting layer to the doping material is 97:3.

[0096] Compound 1 was vacuum-deposited as an electron transport layer on top of the luminescent layer at a deposition rate of 0.1 nm / s, resulting in a film thickness of 30 nm. 0.5 nm of LiF and 150 nm of Al were then vacuum-deposited on the electron transport layer as an electron injection layer and a cathode, respectively. The brightness, driving voltage, current efficiency, and lifetime of the fabricated organic electroluminescent device were measured.

[0097] Device Examples 2-7

[0098] Device Examples 2 to 7 each provide an organic electroluminescent device, which differs from Device Example 1 only in that the electron transport material is different (see Table 1 below), while other conditions are the same as those in Device Example 1.

[0099] Device Comparison Examples 1-3

[0100] Comparative Examples 1 to 3 each provide an organic electroluminescent device, which differs from Device Example 1 only in that the electron transport material is different (see Table 1 below), while other conditions are the same as Device Example 1.

[0101] Performance testing

[0102] Test Method: The driving voltage, current efficiency, and lifetime LT90 of the OLED devices provided above were tested. LT90 refers to the time required for the brightness to decrease to 90% of its original brightness while maintaining an initial brightness of 1000 nits at a constant current density. Test items included the brightness, driving voltage, current efficiency, and lifetime LT90 of the organic light-emitting diode. The driving voltage, current efficiency, and LT90 data were all based on a brightness of 1000 cd / m². 2 The relative values ​​at different times (based on device comparison example 1). The performance test results of the organic electroluminescent devices are shown in Table 1 below:

[0103] Table 1

[0104]

[0105] As shown in Table 1, this invention has obtained heterocyclic compounds through molecular design, which can be used as electron transport materials for OLED light-emitting devices, enabling OLED light-emitting devices to have lower driving voltage, higher current efficiency and longer lifespan.

[0106] The present invention has been illustrated with the above embodiments to describe the detailed process flow of the present invention. However, 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 improvements to the present invention, equivalent substitutions of the 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 heterocyclic compound, characterized in that, The heterocyclic compound has the structure shown in Formula I: In Formula I, R1 and R2 are each independently selected from substituted or unsubstituted C6 to C6. 30 Aryl, substituted or unsubstituted C3-C 30 Any one of the heteroaryl groups; The substituents are each independently selected from cyano, C1-C1 groups. 12 Alkyl, C6-C 30 Aryl, C3~C 30 Any one of the heteroaryl groups; L1 is selected from C6~C 30 aryl or C3~C 30 Any of the heteroaryl groups; n is an integer selected from 0 to 1.

2. The heterocyclic compound according to claim 1, characterized in that, The C6~C 30 The aryl group is selected from phenyl, biphenyl, terphenyl, naphthyl, anthracene, indyl, fluorenyl, perylene, phenanthryl, pyrene, fluoranyl, or benzophenanthryl; The C6~C 30 The arylene group is selected from phenylene, biphenylene, terphenylene, naphthylene, anthracene, indene, fluorene, perylene, phenanthrene, pyrene, fluoranthylene, or benzophenanthrene.

3. The heterocyclic compound according to claim 1, characterized in that, The C3~C 30 heteroaryl, C3~C 30 The heteroatoms in the heteroaryl group are each independently selected from oxygen, sulfur, or nitrogen atoms.

4. The heterocyclic compound according to claim 1, characterized in that, The C3~C 30 The heteroaryl group is selected from benzofuranyl, benzothiophenyl, pyridyl, dibenzofuranyl, pyrimidinyl, dibenzothiophenyl, carbazoyl, N-phenylcarbazoyl, benzofuranocarbazoyl, benzofuranothiophenyl or triazineyl; The C3~C 30 The heteroaryl group is selected from benzofuranyl, benzothiophene, pyridinyl, dibenzofuranyl, pyrimidinyl, dibenzothiophene, carbazoyl, N-phenylcarbazoyl, benzofuranocarbazoyl, benzofuranothiophene, or triazineyl.

5. The heterocyclic compound according to claim 1, characterized in that, The heterocyclic compound is selected from any one of the following compounds:

6. The application of the heterocyclic compound according to any one of claims 1 to 5 as an electron transport material for organic electroluminescent devices.

7. An organic electroluminescent device, characterized in that, The organic electroluminescent device includes the heterocyclic compound as described in any one of claims 1 to 5.

8. The organic electroluminescent device according to claim 7, characterized in that, The organic electroluminescent device includes a first electrode, a second electrode, and an organic layer disposed between the first electrode and the second electrode; The organic layer includes the heterocyclic compounds.

9. The organic electroluminescent device according to claim 8, characterized in that, The organic layer includes an electron transport layer, which includes the heterocyclic compound.

10. A display device, characterized in that, The display device includes an organic electroluminescent device as described in any one of claims 7 to 9.

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