Phenoxazine compound and application thereof

Abstract

The application provides a phenoxazine compound and application thereof, and relates to the technical field of organic electroluminescent materials. The phenoxazine compound can effectively improve the photoelectric performance and service life of an OLED device as a hole transport material.

Description

Technical Field

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

[0002] Organic Light Emission Diodes (OLEDs) technology can be used to manufacture novel display products and lighting products, and it holds promise as a replacement for existing liquid crystal displays and fluorescent lighting, with a wide range of applications. OLEDs have a sandwich-like structure, consisting of electrode material layers and organic functional materials sandwiched between them. These various functional materials are stacked together according to their intended use to form the OLED device. As a current-emitting device, when a voltage is applied to its two electrodes, and an electric field is used to act on the positive and negative charges in the organic functional material layers, the positive and negative charges recombine in the light-emitting layer, thus generating OLED electroluminescence.

[0003] Currently, OLED display technology has been applied in smartphones, tablets, and other fields, and will further expand into large-screen applications such as televisions. However, compared with the requirements of actual product applications, the luminous efficiency and lifespan of OLED devices still need further improvement. Current research on improving the performance of OLED light-emitting devices includes reducing the driving voltage of the devices, increasing the luminous efficiency of the devices, and increasing the lifespan of the devices. To continuously improve the performance of OLED devices, it is necessary not only to innovate the structure and manufacturing process of OLED devices, but also to continuously research and innovate OLED optoelectronic functional materials to create higher-performance OLED functional materials.

[0004] OLED optoelectronic functional materials used in OLED devices can be broadly categorized into two types based on their applications: charge injection transport materials and luminescent materials. Further, charge injection transport materials can be classified into electron injection transport materials, electron blocking materials, hole injection transport materials, and hole blocking materials; luminescent materials can be categorized into host luminescent materials and doped materials. To fabricate high-performance OLED devices, various organic functional materials are required to possess excellent optoelectronic properties. For example, as charge transport materials, they require good carrier mobility and high glass transition temperature; as host materials for the luminescent layer, they require good bipolarity and appropriate HOMO / LUMO energy levels.

[0005] The optoelectronic functional materials that constitute OLED devices consist of at least two layers. Industrially applied OLED device structures include multiple layers such as hole injection layers, hole transport layers, electron blocking layers, light-emitting layers, hole blocking layers, electron transport layers, and electron injection layers. In other words, the optoelectronic functional materials used in OLED devices include at least hole injection materials, hole transport materials, light-emitting materials, and electron transport materials, exhibiting richness and diversity in material types and combinations. Furthermore, the optoelectronic functional materials used are highly selective for different OLED device structures; the same material can exhibit completely different performance characteristics in different device structures.

[0006] Therefore, considering the current industrial application requirements of OLED devices and the photoelectric characteristic requirements of different functional layers, it is essential to select more suitable and higher-performance OLED functional materials or material combinations to achieve the comprehensive characteristics of high efficiency, long lifespan, and low voltage. In terms of current OLED practical needs, the development of OLED materials is far from sufficient and lags behind the requirements of panel manufacturers, making the development of higher-performance organic functional materials particularly important. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention aims to provide a phenazine compound and its applications. The phenazine compound possesses excellent properties and is suitable as a hole transport material in organic electroluminescent devices.

[0008] To achieve this objective, the present invention adopts the following technical solution:

[0009] In a first aspect, the present invention provides a phenazine compound having a structure as shown in Formula I:

[0010]

[0011] Where, the structure of A is The structure of B is

[0012] Ar1, Ar2, Ar3, Ar4, Ar5, and Ar6 are each independently selected from substituted or unsubstituted C6 to C6. 30 Aryl, substituted or unsubstituted C3-C 30 Aromatic heterocyclic groups;

[0013] Ar3 and Ar4 may be linked by a single bond to form a carbazole ring or may not be linked at all.

[0014] Ar5 and Ar6 may be connected by a single bond to form a carbazole ring or not connected at all.

[0015] In Ar1, Ar2, Ar3, Ar4, Ar5, and Ar6, the substituents are each independently selected from fluorine atoms, cyano groups, and C1-C6 groups. 12 Alkyl, C6-C 30 Aryl or C3~C 30 Aromatic heterocyclic groups;

[0016] In Formula I, the hydrogen atom can be independently replaced by a deuterium atom, a fluorine atom, a cyano group, or a C1-C1 group. 12 Alkyl, C6-C 30 Aryl or C3~C 30 Aromatic heterocyclic substitution.

[0017] Preferably, A and B have the same structure.

[0018] Preferably, Ar3, Ar4, Ar5, and Ar6 are each independently selected from phenyl, biphenyl, or triphenylene, with at least one of Ar3 and Ar4 being triphenylene, and at least one of Ar5 and Ar6 being triphenylene, and Ar3 and Ar4 being different, and Ar5 and Ar6 being different;

[0019] Alternatively, Ar3, Ar4, Ar5, and Ar6 may be independently selected from triphenylene or naphthyl, with Ar3 being different from Ar4 and Ar5 being different from Ar6.

[0020] Preferably, the phenazine compound has a structure as shown in Formula II:

[0021]

[0022] In Formula II, Ar1 and Ar2 are each independently selected from substituted or unsubstituted C6 to C6. 30 Aryl, substituted or unsubstituted C3-C 30 Aromatic heterocyclic groups, wherein each substituent is independently selected from a fluorine atom, a cyano group, or a C1-C2 group. 12 Alkyl, C6-C 30 Aryl or C3~C 30 Aromatic heterocyclic groups;

[0023] Ar7 and Ar8 have the same structure, and Ar7 and Ar8 are selected from phenyl, biphenyl or naphthyl.

[0024] Preferably, C1 to C 12 The alkyl group is selected from methyl, ethyl, propyl, isopropyl, butyl, tert-butyl, pentyl, p-pentyl, n-hexyl, or cyclohexyl.

[0025] In this invention, aryl refers to the general term for monovalent groups remaining after removing a hydrogen atom from the aromatic carbon atom of an aromatic hydrocarbon molecule. It can be a monocyclic aryl or a fused-ring aryl, wherein the C6-C6 group... 30Aryl groups include, but are not limited to, phenyl, biphenyl, terphenyl, triphenylene, naphthyl, anthracene, indyl, fluorenyl, perylene, phenanthryl, pyrene, fluoranyl, or benzophenanthryl.

[0026] In this invention, aromatic heterocyclic groups refer to the general term for groups obtained by replacing one or more aromatic nucleus carbons in an aryl group with heteroatoms, and can be monocyclic heteroaryl or fused-ring heteroaryl. The C3-C... 30 The heteroatoms in aromatic heterocyclic groups include, but are not limited to, oxygen, sulfur, silicon, boron, or nitrogen atoms. The C3-C... 30 Aromatic heterocyclic groups include, but are not limited to, benzofuranyl, benzothiophenyl, dibenzofuranyl, dibenzothiophenyl, carbazoyl, diaryleneamine, benzofuranocarbazoyl, benzofuranothiophenyl, or triazineyl.

[0027] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. The purpose and beneficial effects of the present invention can be better achieved and realized through the following preferred technical solutions.

[0028] Preferably, the phenazine compound includes any one of compounds 1 to 68 below:

[0029]

[0030]

[0031]

[0032] This invention lists some specific structural forms of the phenazine compounds, but the phenazine compounds described in this invention are not limited to the listed chemical structures. Any structure based on the structure shown in Formula I, where Ar1, Ar2, Ar3, Ar4, Ar5, and Ar6 satisfy the above-mentioned limiting conditions should be included.

[0033] Secondly, the present invention provides an application of the phenazine compound described above as a hole transport material in an organic electroluminescent device.

[0034] Thirdly, the present invention provides an organic electroluminescent device, the organic electroluminescent device comprising phenazine compounds as described in the first aspect.

[0035] 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; the material of the organic layer includes phenazine compounds as described in the first aspect.

[0036] Preferably, the organic layer comprises a hole transport layer; the material of the hole transport layer comprises a phenazine compound as described in the first aspect.

[0037] Fourthly, the present invention provides a display device comprising the organic electroluminescent device as described in the third aspect.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] The phenazine compounds of this invention have good thermal stability and luminescence properties, and can be used to prepare organic electroluminescent devices, especially as hole transport layer materials in organic electroluminescent devices, which can effectively reduce the driving voltage of organic electroluminescent devices and improve the current efficiency of organic electroluminescent devices. Detailed Implementation

[0040] 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.

[0041] Synthesis Example 1

[0042] This embodiment provides a method for synthesizing compound 1. The synthetic route of compound 1 is as follows:

[0043]

[0044] 49 g of dibromophenazine-1, 40.56 g of diphenylamine, 55.2 g of sodium tert-butyloxide, 4.5 g of tris(dibenzylacetone)dipalladium, 5.6 g of tri-tert-butylphosphine tetrafluoroborate, and 500 mL of toluene were mixed and heated under reflux for 12 h under argon protection. After the reaction was completed, 500 mL of water was added, the organic phase was separated, and the separated organic phase was dried and the solvent was removed by distillation. 48.7 g of compound 1 was obtained by silica gel chromatography (using a mixture of toluene and n-hexane in a 1:1 volume ratio).

[0045] Mass spectrometry analysis of compound 1 yielded a charge-to-mass ratio (m / z) of 668.3.

[0046] Synthesis Example 2

[0047] This embodiment provides a method for synthesizing compound 2. The synthetic route of compound 2 is as follows:

[0048]

[0049] Following the synthesis method of Synthesis Example 1, carbazole was used to replace diphenylamine in Synthesis Example 1, while other conditions remained unchanged, to obtain compound 2.

[0050] The mass spectrometry analysis of compound 2 yielded a charge-to-mass ratio of m / z of 664.3.

[0051] Synthesis Example 3

[0052] This embodiment provides a method for synthesizing compound 3. The synthetic route of compound 3 is as follows:

[0053]

[0054] Following the synthesis method of Synthesis Example 1, dibromophenazine-2 was used to replace dibromophenazine-1 in Synthesis Example 1, while keeping other conditions unchanged, to obtain compound 3.

[0055] Mass spectrometry analysis of compound 3 yielded a charge-to-mass ratio (m / z) of 668.3.

[0056] Synthesis Example 4

[0057] This embodiment provides a method for synthesizing compound 4. The synthetic route of compound 4 is as follows:

[0058]

[0059] Following the synthesis method of Synthesis Example 3, carbazole was used to replace diphenylamine in Synthesis Example 3, while other conditions remained unchanged, to obtain compound 4.

[0060] Mass spectrometry analysis of compound 4 yielded a charge-to-mass ratio (m / z) of 664.3.

[0061] Synthesis Example 5

[0062] This embodiment provides a method for synthesizing compound 65, and the synthetic route is as follows:

[0063]

[0064] Following the synthesis method of Synthesis Example 4, amine-1 was used to replace carbazole in Synthesis Example 4, while other conditions remained unchanged, to obtain compound 65.

[0065] Mass spectrometry analysis of compound 65 yielded a charge-to-mass ratio (m / z) of 968.4.

[0066] Synthesis Example 6

[0067] This embodiment provides a method for synthesizing compound 66, and the synthetic route is as follows:

[0068]

[0069] Following the synthesis method of Synthesis Example 4, amine-2 was used to replace carbazole in Synthesis Example 4, while other conditions remained unchanged, to obtain compound 66.

[0070] Mass spectrometry analysis of compound 66 yielded a charge-to-mass ratio (m / z) of 1120.5.

[0071] Synthesis Example 7

[0072] This embodiment provides a method for synthesizing compound 67, and the synthetic route is as follows:

[0073]

[0074] Following the synthesis method of Synthesis Example 4, amine-3 was used to replace carbazole in Synthesis Example 4, while other conditions remained unchanged, to obtain compound 67.

[0075] Mass spectrometry analysis of compound 67 yielded a charge-to-mass ratio (m / z) of 1068.4.

[0076] Synthesis Example 8

[0077] This embodiment provides a method for synthesizing compound 68, and the synthetic route is as follows:

[0078]

[0079] Following the synthesis method of Synthesis Example 4, amine-4 was used to replace carbazole in Synthesis Example 4, while other conditions remained unchanged, to obtain compound 68.

[0080] Mass spectrometry analysis of compound 68 yielded a charge-to-mass ratio (m / z) of 1068.4.

[0081] Other compounds for which specific synthesis steps are not listed can be prepared using common knowledge in the art, in conjunction with the above synthesis examples.

[0082] The specific structures of some of the compounds used in the following device embodiments and device comparative examples are shown below:

[0083]

[0084] In the following device embodiments, phenazine compounds provided by the present invention are selected as hole transport materials in organic electroluminescent devices, and the device comparative examples use the above-mentioned H-1 as hole transport materials in organic electroluminescent devices.

[0085] Device Example 1

[0086] The device embodiment provides an organic electroluminescent device, using compound 1 provided in synthesis embodiment 1 of the present invention as a hole transport material.

[0087] The organic electroluminescent device has the following structure:

[0088] ITO (150nm) / HAT-CN (10nm) / Compound 1 (60nm) / EB-1 (10nm) / BH:BD 5% (35nm) / TPBI&LiQ (35nm) / LiF (1nm) / Al (100nm).

[0089] The fabrication method of the above-mentioned organic electroluminescent device is as follows:

[0090] Transparent glass was used as the substrate layer, and ITO with a thickness of 150nm was coated on it as the anode layer. The substrate was then subjected to alkaline washing, pure water washing, drying, and ultraviolet-ozone washing to remove organic residues from the surface of the transparent ITO.

[0091] After washing, HAT-CN with a thickness of 10 nm was deposited on the ITO anode layer using a vacuum evaporation device as a hole injection layer.

[0092] Next, a 60 nm thick compound 1 was deposited as a hole transport layer. Then, a 10 nm thick EB-1 was deposited as an electron blocking layer.

[0093] Subsequently, a light-emitting layer with a thickness of 35 nm is obtained by vacuum evaporation on the electron blocking layer. The light-emitting layer consists of a host material BH and a dopant material BD, with a mass ratio of BH to BD of 95:5.

[0094] Then, an electron transport layer with a thickness of 35 nm is vacuum-deposited on the light-emitting layer. The electron transport layer consists of TPBI and Liq in a mass ratio of 1:1.

[0095] Next, a 1 nm thick lithium fluoride (LiF) layer is vacuum-deposited on the electron transport layer as an electron injection layer. Finally, a 100 nm thick aluminum (Al) layer is vacuum-deposited on the electron injection layer as a cathode layer.

[0096] Device Examples 2-10

[0097] Device Examples 2 to 10 each provide an organic electroluminescent device, which differs from Device Example 1 only in that the hole transport material is different (see Table 1 below), while other conditions are the same as those in Device Example 1.

[0098] Device Comparison Example 1

[0099] Comparative Example 1 provides an organic electroluminescent device, which differs from Device Example 1 only in that the hole transport material is different (see Table 1 below), while other conditions are the same as Device Example 1.

[0100] Performance testing

[0101] The driving voltage, current efficiency, and lifetime (LT95) of the OLED devices provided above were tested. LT95 refers to the time required for the brightness to decrease to 95% of its original brightness while maintaining an initial brightness of 1000 nits at a constant current density. Test items included the brightness, driving voltage, and current efficiency of the organic light-emitting diode. The driving voltage, current efficiency, and LT95 data were all based on a brightness of 1000 cd / m². 2 The relative values ​​at different times (with material H-1 as the comparison benchmark). The performance test results of the organic electroluminescent devices are shown in Table 1 below:

[0102] Table 1

[0103]

[0104] As shown in Table 1, the phenazine compounds provided by this invention can be used as hole transport materials for OLED light-emitting devices, resulting in lower driving voltage, higher current efficiency, and longer lifetime for the OLED light-emitting devices. Specifically, as seen in Examples 11-14, when the nitrogen atoms in the two nitrogen-containing groups connected to the phenazine core of the compound are simultaneously connected to both triphenylene and phenyl groups, the OLED light-emitting device exhibits an outstanding lifetime, for example, compound 65; when the nitrogen atoms in the two nitrogen-containing groups connected to the phenazine core of the compound are simultaneously connected to both triphenylene and biphenyl groups, the OLED light-emitting device exhibits an outstanding lifetime, for example, compound 66; and when the nitrogen atoms in the two nitrogen-containing groups connected to the phenazine core of the compound are simultaneously connected to both triphenylene and naphthyl groups, the OLED light-emitting device exhibits outstanding current efficiency and significantly reduces the driving voltage, for example, compounds 67-68.

[0105] The applicant declares that the detailed process flow of this invention is illustrated by the above embodiments, but this invention is not limited to the above detailed process flow, that is, it does not mean that this invention must rely on the above detailed process flow to be implemented. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of raw materials for the product of this invention, addition of auxiliary components, and selection of specific methods, etc., all fall within the protection scope and disclosure scope of this invention.

Claims

1. A phenazine compound, characterized in that, The phenazine compounds described above have the structure shown in Formula I: ； Formula I Where, the structure of A is The structure of B is The structures of A and B are identical; Ar1 and Ar2 are each independently selected from phenyl, biphenyl, or naphthyl groups; Ar3, Ar4, Ar5, and Ar6 are each independently selected from phenyl, biphenyl, or triphenylene, with at least one of Ar3 and Ar4 being triphenylene, and at least one of Ar5 and Ar6 being triphenylene, and Ar3 and Ar4 being different, and Ar5 and Ar6 being different; Alternatively, Ar3, Ar4, Ar5, and Ar6 may be independently selected from triphenylene or naphthyl, and Ar3 may be different from Ar4, and Ar5 may be different from Ar6; Ar3 and Ar4 are not connected; Ar5 and Ar6 are not connected; In Formula I, the hydrogen atom can be independently replaced by a deuterium atom, a fluorine atom, a cyano group, or a C1~C1 group. 12 Alkyl substitution; The C1~C 12 The alkyl group is selected from methyl, ethyl, propyl, isopropyl, butyl, tert-butyl, pentyl, p-pentyl, or n-hexyl.

2. The phenazine compound according to claim 1, characterized in that, The phenazine compounds include any one of the following compounds 65-68: 。 3. The application of the phenazine compounds according to claim 1 or 2 as hole transport materials in organic electroluminescent devices.

4. An organic electroluminescent device, characterized in that, The organic electroluminescent device includes phenazine compounds as described in claim 1 or 2.

5. The organic electroluminescent device according to claim 4, 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 a hole transport layer; the material of the hole transport layer includes the phenazine compound.

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