A 6,6-dimethyl-6H-benzo[cd]pyrene compound and its intermediates, an organic electroluminescent device and a display device.

Abstract

This invention provides a 6,6-dimethyl-6H-benzo[cd]pyrene compound and its intermediates, an organic electroluminescent device, and a display device, relating to the field of organic optoelectronic technology. The general structural formula of the 6,6-dimethyl-6H-benzo[cd]pyrene compound is: where m and n are each independently selected from 0 or 1; the hydrogen atoms in formula I are each independently replaced by deuterium atoms, F, CN, C1-C1 atoms. 12 Alkyl, C6-C 30 Aryl or C3-C 30 The aromatic heterocyclic group may or may not be substituted. This invention designs the structure of 6,6-dimethyl-6H-benzo[cd]pyrene compounds, and the obtained 6,6-dimethyl-6H-benzo[cd]pyrene compounds have excellent properties. Organic electroluminescent devices prepared as light-emitting layer materials have low driving voltage, high current efficiency and long lifetime.

Description

Technical Field

[0001] This invention belongs to the field of organic optoelectronic technology, specifically relating to a 6,6-dimethyl-6H-benzo[cd]pyrene compound and its intermediates, organic electroluminescent devices, and display devices. Background Technology

[0002] Organic light-emitting diodes (OLEDs) are display components that utilize self-emissive properties. They have a wider viewing angle and are thinner, lighter, and faster than liquid crystal displays. They can also achieve flexible displays, making them highly anticipated for use as full-color display components or lighting equipment.

[0003] Organic light emission typically refers to the phenomenon of converting electrical energy into light energy using organic materials. Organic light-emitting devices that utilize organic light emission usually have a structure that includes an anode, a cathode, and an organic layer sandwiched between the anode and the cathode.

[0004] In organic light-emitting elements (OLEDs), the organic layer is often composed of a multilayer structure made of different materials to improve efficiency and stability. For example, it may consist of a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, and an electron injection layer. When a voltage is applied between the two electrodes in this OLED structure, holes from the anode are injected into the organic layer, and electrons from the cathode are also injected into the organic layer. When the injected holes and electrons meet, they form excitons. When these excitons release energy and transition to the ground state, they emit photons, thus producing light. OLEDs are widely recognized for their self-emissive nature, high brightness, high efficiency, low driving voltage, wide viewing angle, high contrast, and high-speed response.

[0005] Currently, 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, and their transmission performance and luminous efficiency restrict the industrialization of these devices. Therefore, designing and searching for a compound as a novel OLED material to overcome its shortcomings in practical applications is a key focus and future research trend in OLED materials research. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a 6,6-dimethyl-6H-benzo[cd]pyrene compound, its intermediates, an organic electroluminescent device, and a display device. The present invention designs 6,6-dimethyl-6H-benzo[cd]pyrene compounds based on their structures, resulting in 6,6-dimethyl-6H-benzo[cd]pyrene compounds with excellent properties, making them suitable as light-emitting layer materials in organic electroluminescent devices.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a 6,6-dimethyl-6H-benzo[cd]pyrene compound, wherein the 6,6-dimethyl-6H-benzo[cd]pyrene compound has the structure shown in Formula I:

[0009]

[0010] Where m and n are each independently selected from 0 or 1;

[0011] In the compound, each hydrogen atom is independently replaced by a deuterium atom, F, CN, or Cl-C atom. 12 Alkyl, C6-C 30 Aryl, C3~C 30 The aromatic heterocyclic group may or may not be substituted.

[0012] The C6-C 30 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, and exemplary groups include but are not limited to: phenyl, biphenyl, terphenyl, naphthyl, anthracene, indene, fluorenyl, perylene, phenanthrene, pyrene, fluoranyl, and benzo[a]phenanthrene.

[0013] The C3-C 30 The aromatic heterocyclic group is selected from dibenzofuranyl, dibenzothiophenyl, carbazoyl, naphthobenzofuranyl, naphthobenzothiophenyl, and benzocarbazoyl.

[0014] The C1-C 12 The alkyl group is selected from methyl, ethyl, propyl, isopropyl, butyl, tert-butyl, pentyl, p-pentyl, n-hexyl, and cyclohexyl;

[0015] As a preferred technical solution of the present invention, in Formula I, m and n are both selected from 0.

[0016] As a preferred technical solution of the present invention, in Formula I, m and n are both selected from 1.

[0017] As a preferred technical solution of the present invention, in formula I, m+n=1.

[0018] As a preferred embodiment of the present invention, the hydrogen atoms in the compound of formula I can be independently replaced by one or a combination of two of phenyl, carbazolyl, naphthyl, biphenyl, 9,9-dimethylfluorenyl, and dibenzofuranyl.

[0019] As a preferred embodiment of the present invention, the 6,6-dimethyl-6H-benzo[cd]pyrene compound includes any one of the following compounds:

[0020]

[0021]

[0022]

[0023]

[0024]

[0025] Preferably, the 6,6-dimethyl-6H-benzo[cd]pyrene compound comprises any one of the following compounds:

[0026]

[0027] This invention lists some specific structural forms of the 6,6-dimethyl-6H-benzo[cd]pyrene compounds, but the 6,6-dimethyl-6H-benzo[cd]pyrene compounds of this invention are not limited to these listed chemical structures. Any structure based on the structure shown in Formula I that meets the above-mentioned limiting conditions should be included.

[0028] The preparation method of the 6,6-dimethyl-6H-benzo[cd]pyrene compounds of this application is illustrated below with an example:

[0029]

[0030] X1 and X2 are each independently selected from F, Cl, Br or I;

[0031] m and n are each independently selected from 0 or 1.

[0032] The present invention also provides an intermediate of a 6,6-dimethyl-6H-benzo[cd]pyrene compound having the structure shown in formula MA:

[0033]

[0034] X1 is selected from F, Cl, Br or I;

[0035] m and n are each independently selected from 0 or 1.

[0036] MA was used to synthesize the 6,6-dimethyl-6H-benzo[cd]pyrene compounds of the present invention.

[0037] Preferably, the intermediate is selected from the following structures:

[0038]

[0039] In a second aspect, the present invention provides an organic electroluminescent device comprising 6,6-dimethyl-6H-benzo[cd]pyrene compounds as described in the first aspect.

[0040] 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;

[0041] The material of the organic layer includes 6,6-dimethyl-6H-benzo[cd]pyrene compounds as described in the first aspect.

[0042] Preferably, the organic layer includes a light-emitting layer;

[0043] The host material of the light-emitting layer includes 6,6-dimethyl-6H-benzo[cd]pyrene compounds as described in the first aspect.

[0044] Thirdly, the present invention provides a display device comprising the organic electroluminescent device as described in the second aspect.

[0045] Compared with the prior art, the present invention has the following beneficial effects:

[0046] This invention designs the structure of 6,6-dimethyl-6H-benzo[cd]pyrene compounds. A carbazole group is attached to the benzene ring of the phenyl-substituted 6,6-dimethyl-6H-benzo[cd]pyrene compound. The carbazole group has a high triplet energy level. 6,6-dimethyl-6H-benzo[cd]pyrene has a large conjugated planar structure, resulting in good charge transport performance. Furthermore, the two methyl groups on 6,6-dimethyl-6H-benzo[cd]pyrene improve the film-forming properties of the molecule. This structural design enables the compounds of this invention to possess excellent luminescent properties and can be used to prepare organic electroluminescent devices, especially as the main material of the light-emitting layer in organic electroluminescent devices. This effectively reduces the driving voltage and improves the current efficiency of organic electroluminescent devices. Detailed Implementation

[0047] To facilitate understanding of the present invention, preparation examples and embodiments are provided below. Those skilled in the art should understand that the preparation examples and embodiments are merely illustrative and should not be considered as specific limitations of the present invention.

[0048] Preparation Example 1

[0049] This preparation example provides a method for synthesizing intermediate A, as follows:

[0050]

[0051] (1) Synthesis of intermediate A-2

[0052] In a three-necked flask under a nitrogen atmosphere, 3.4 g of intermediate A-1 and 60 mL of tetrahydrofuran were added. The mixture was then cooled to -75 °C, and a 0.01 mol butyllithium solution in n-hexane (1.6 M, 6.3 mL) was slowly added. The mixture was then kept at -78 °C to -60 °C for 30 min. 1.5 g of trimethyl borate was slowly added, and the mixture was slowly heated to room temperature and stirred for 2 hours. Dilute hydrochloric acid and ethyl acetate were added, and the mixture was separated. The organic layer was washed with a saturated sodium chloride solution and concentrated to dryness. The resulting viscous solid was intermediate A-2, which was directly used for the following reaction without further separation.

[0053] (2) Synthesis of intermediate A

[0054] Under nitrogen protection, 60 mL of toluene, 30 mL of ethanol, and 20 mL of water were added sequentially to a three-necked flask. Then, 3.6 g of the intermediate A-2 prepared in the previous step was added. 2.12 g (0.02 mol) of sodium carbonate and 0.23 g (0.0002 mol) of tetrakis(triphenylphosphine) palladium were slowly heated to reflux for 8 h, cooled to room temperature, and water was added to liquefy the mixture. The organic layer was washed with water, dried with magnesium sulfate, and the desiccant was removed. The mixture was then concentrated to dryness and separated by silica gel column chromatography with petroleum ether:dichloromethane = 10:2 (volume ratio) as elution to give 2.1 g of intermediate A.

[0055] The obtained intermediate A was subjected to mass spectrometry analysis, and the mass-to-charge ratio (m / z) was measured to be 574.13.

[0056] Preparation Example 2

[0057] This preparation example provides a method for synthesizing intermediate B, as follows:

[0058]

[0059] Intermediate B was prepared using the same method as intermediate A.

[0060] The obtained intermediate B was subjected to mass spectrometry analysis, and the mass-to-charge ratio (m / z) was measured to be 574.13.

[0061] Preparation Example 3

[0062] This preparation example provides a method for synthesizing intermediate C, as follows:

[0063]

[0064] Intermediate C was prepared by referring to the preparation method of intermediate A.

[0065] The obtained intermediate C was subjected to mass spectrometry, and the mass-to-charge ratio (m / z) was measured to be 422.07.

[0066] Preparation Example 4

[0067] This preparation example provides a method for synthesizing intermediate D, as follows:

[0068]

[0069] Intermediate D was prepared by referring to the preparation method of intermediate A.

[0070] The obtained intermediate D was subjected to mass spectrometry analysis, and the mass-to-charge ratio (m / z) was measured to be 422.07.

[0071] Preparation Example 5

[0072] This preparation example provides a method for synthesizing intermediate E, as follows:

[0073]

[0074] Intermediate E was prepared by referring to the preparation method of intermediate A.

[0075] The obtained intermediate E was analyzed by mass spectrometry, and the mass-to-charge ratio (m / z) was found to be 422.07.

[0076] Preparation Example 6

[0077] This preparation example provides a method for synthesizing intermediate F, as follows:

[0078]

[0079] Intermediate F was prepared by referring to the preparation method of intermediate A.

[0080] The obtained intermediate F was subjected to mass spectrometry, and the mass-to-charge ratio (m / z) was measured to be 498.10.

[0081] Synthesis Example 1

[0082] This embodiment provides a method for synthesizing compound 1, as follows:

[0083]

[0084] Under nitrogen protection, dry toluene (100 mL), intermediate A (5.7 g), carbazole (1.7 g), Pd(dba)2 (bis(dibenzylacetone)palladium, 0.0575 g, 0.0001 mol), a 10% (w / w) solution of tri-tert-butylphosphine in toluene (w / w) was 0.4 g of tri-tert-butylphosphine solution and 0.0002 mol of tri-tert-butylphosphine, and sodium tert-butoxide (1.44 g, 0.015 mol) were added to a three-necked flask. The mixture was heated to reflux and reacted for 12 h. After cooling to room temperature, water was added to dissolve the mixture. The organic layer was then washed with water until neutral, dried with magnesium sulfate, filtered to remove magnesium sulfate, concentrated to dryness, and crystallized from toluene to obtain compound 1 (4.7 g).

[0085] Mass spectrometry analysis of compound 1 showed a mass-to-charge ratio (m / z) of 661.28.

[0086] Synthesis Examples 2-8

[0087] Following the synthesis method of compound 1, the following compounds were prepared using different raw materials, and mass spectra were measured and the mass-to-charge ratios (m / z) were recorded as shown in Table 1.

[0088] Table 1

[0089]

[0090]

[0091]

[0092] 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.

[0093] In this invention, the specific structure of the materials used in the following application examples is as follows:

[0094]

[0095] H-1 Synthesis

[0096]

[0097] Following the same method used to synthesize compound 1, compound H-1 was synthesized.

[0098] Mass spectrometry analysis of compound H-1 showed a mass-to-charge ratio (m / z) of 598.24.

[0099] H-2 Synthesis

[0100]

[0101] Following the same method used to synthesize compound 1, compound H-2 was synthesized.

[0102] Mass spectrometry analysis of compound H-2 showed a mass-to-charge ratio (m / z) of 433.18.

[0103] Device Example 1

[0104] The device embodiment provides an organic electroluminescent device, using compound 1 provided in synthesis embodiment 1 of the present invention as the host material of the light-emitting layer; the structure of the organic electroluminescent device is as follows:

[0105] ITO / HT (40nm) / Emitting layer main material: PGD-16% (30nm) / TPBI (30nm) / LiF (0.5nm) / Al (150nm).

[0106] The fabrication method of the above-mentioned organic electroluminescent device is as follows:

[0107] 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 layer.

[0108] The material was placed inside a vacuum chamber, and the vacuum was evacuated to 1×10⁻⁶. -5 -1×10 -6 Pa is sequentially vacuum-deposited onto the cleaned ITO substrate. The light-emitting layer substrate material, PGD-16% (30nm), refers to the fact that in the device, the light-emitting layer substrate material and PGD-1 are co-evaporated at a volume ratio of 94:6 to form the light-emitting layer, with a thickness of 30nm.

[0109] Device Examples 2-8

[0110] Device Examples 2-8 each provide an organic electroluminescent device, which differs from Device Example 1 only in that the main material of the light-emitting layer is different (see Table 2 below), while other conditions are the same as those in Device Example 1.

[0111] Device Comparison Examples 1-3

[0112] Comparative Examples 1-3 each provide an organic electroluminescent device, which differs from Device Example 1 only in that the main body of the light-emitting layer is different (see Table 2 below), while other conditions are the same as Device Example 1.

[0113] Performance testing

[0114] 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, and current efficiency of the organic electroluminescent device. 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. The performance test results of organic electroluminescent devices are shown in Table 2 below:

[0115] Table 2

[0116]

[0117]

[0118] As shown in Table 2, this invention, through molecular design, yielded compounds with 6,6-dimethyl-6H-benzo[cd]pyrene. These compounds can be used as the main material for the light-emitting layer of OLED devices, resulting in lower driving voltage, higher current efficiency, and longer lifetime for the OLED devices.

[0119] 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 6,6-dimethyl-6H-benzo[cd]pyranyl compound characterized in that, The 6,6-dimethyl-6H-benzo[cd]pyrene compound is selected from any one of the following compounds: 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 。 2. The 6,6-dimethyl-6H-benzo[cd]pyrancium compound according to claim 1, characterized in that, The 6,6-dimethyl-6H-benzo[cd]pyrene compound is selected from any one of the following compounds: 、 、 、 、 、 、 、 。 3. An intermediate of a 6,6-dimethyl-6H-benzo[cd]pyranyl compound, characterized by, having a structure of Formula MA: ； wherein X1 is selected from F, Cl, Br or I; m, n are each independently selected from 0 or 1.

4. The intermediate of the 6,6-dimethyl-6H-benzo[cd]pyrancium compound according to claim 3, characterized in that, The intermediate is selected from the following structures: 、 、 、 、 、 。 5. An organic electroluminescent device, characterized by The organic electroluminescent device comprises the 6,6-dimethyl-6H-benzo[cd]pyrene compound of claim 1 or 2.

6. The organic electroluminescent device according to claim 5, 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 material of the organic layer comprises the 6,6-dimethyl-6H-benzo[cd]pyrene compound.

7. The organic electroluminescent device according to claim 6, characterized in that The organic layer comprises an emitting layer; The host material of the emitting layer comprises the 6,6-dimethyl-6H-benzo[cd]pyrene compound.

8. A display device, characterized by comprising: The organic electroluminescent device of any one of claims 5-7.

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