Boron-nitrogen compounds, electroluminescent device and display apparatus

Abstract

Disclosed in the embodiments of the present application are boron-nitrogen compounds, an electroluminescent device and a display apparatus. The structural general formula of the boron-nitrogen compounds is shown as formula (I).

Description

Boron nitrogen compound, electroluminescent device and display device

[0001] This application claims priority to Chinese patent application No. 202410370410.9 filed on March 28, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0002] The present application relates to the technical field of organic optoelectronic materials, and in particular to a boron-nitrogen compound, an electroluminescent device, and a display apparatus. Background Art

[0003] The luminescent materials in the light-emitting layer of organic light-emitting diode (OLED) devices can be divided into fluorescent and phosphorescent materials based on the spin multiplicity of the luminescent energy level. According to the laws of quantum statistics, the ratio of singlet excited state excitons to triplet excited state excitons generated in an electric field is 1:3. Traditional fluorescent materials are affected by spin prohibition, and their exciton utilization rate is only 25% at most. In contrast, phosphorescent materials and thermally activated delayed fluorescence (TADF) materials can achieve a theoretical maximum exciton utilization rate of 100% due to the spin-flip processes of intersystem crossing (ISC) and reverse intersystem crossing (RISC). See C. Adachi, et al., Nature, Vol. 492, 234, (2012).

[0004] However, in practical applications, energy transfer and exciton dissipation in singlet and triplet excitons, which are affected by various exciton quenching mechanisms and are unfavorable for radiative transitions, can negatively impact OLED device performance, resulting in device degradation, short lifetime, large roll-off at high brightness, and limited device current efficiency. Using phosphorescent or TADF materials to sensitize narrow-emission fluorescent or phosphorescent materials in OLED devices improves the efficiency of spectral energy transfer between the materials and holds promise for enhancing OLED device performance. To develop OLED devices with narrow emission and high efficiency, it is necessary to select materials with appropriate spectral and energy level characteristics for the sensitization system of the light-emitting layer. Multi-resonance fluorescent materials containing boron (B) and nitrogen (N) atoms have attracted considerable attention due to their rigid luminescent cores, resulting in small Stokes shifts, narrow spectra, and high luminescence efficiency. Boron-nitrogen (BN) materials emitting in the blue-green wavelength range have been developed for a long time, while red-emitting materials have lagged behind. In particular, red-emitting materials are limited by the energy gap and are more prone to nonradiative transitions after excitation. Consequently, their luminescence efficiency and lifetime differ significantly from those of blue-green BN materials.

[0005] Summary of the Invention

[0006] The prior art has the technical problem that the lifespan and luminous efficiency of red light OLED devices need to be improved. In a first aspect, the embodiments of the present application provide a boron nitrogen compound, the general structural formula of which is shown in formula (I):

[0007] wherein X1 is selected from O or N;

[0008] When X1 is selected from O, Z is selected from non-bonding, and one of Y1 and Y2 is selected from -O-, -S-, -Se-, -Te-, -CC-, -C=C-, The other is selected from non-bonding, single bond, -O-, -S-, -Se-, -Te-, -CC-, -C=C-,

[0009] When X1 is selected from N, Z is selected from an aromatic or heterocyclic group having 4 to 50 carbon atoms and substituted or unsubstituted with deuterium, tritium, halogen, an alkyl group having 1 to 50 carbon atoms or an alkoxy group having 1 to 50 carbon atoms, and one of Y1 and Y2 is selected from -O-, -S-, -Se-, -Te-, -CC-, -C=C-, The other is selected from non-bonding, single bond, -O-, -S-, -Se-, -Te-, -CC-, -C=C-, Z and A6 form a ring or not;

[0010] R1-R 12Each is independently selected from an aromatic group or heterocyclic group having 4 to 50 carbon atoms, which is substituted or unsubstituted with deuterium, tritium, halogen, an alkyl group having 1 to 50 carbon atoms, or an alkoxy group having 1 to 50 carbon atoms;

[0011] A1 to A6 are each independently selected from an aromatic group or heterocyclic group having 4 to 50 carbon atoms, which is unsubstituted or substituted with deuterium, tritium, halogen, an alkyl group having 1 to 50 carbon atoms, or an alkoxy group having 1 to 50 carbon atoms.

[0012] In a second aspect, an embodiment of the present application further provides an electroluminescent device comprising an anode and a cathode, and a light-emitting layer located between the anode and the cathode, wherein the light-emitting layer comprises the above-mentioned boron nitrogen compound.

[0013] In a third aspect, an embodiment of the present application further provides a display device comprising the above-mentioned electroluminescent device. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solutions in the embodiments or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0015] FIG1 is a schematic diagram of a film stack structure of an electroluminescent device provided in an embodiment of the present application. Modes for Carrying Out the Invention

[0016] This application provides a boron-nitrogen compound, an electroluminescent device, and a display device. To clarify and clarify the objectives, technical solutions, and effects of this application, the application is described in further detail below. It should be understood that the specific embodiments described herein are intended only to illustrate this application and are not intended to limit it.

[0017] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application. In this application, "substituted" means that a hydrogen atom in a substituted group is replaced by a substituent; a group or structural unit "not forming a bond" means that the group or structural unit does not exist.

[0018] As used herein, "substituted or unsubstituted" means that the hydrogen atoms on the defined group may or may not be substituted. When a defined group is substituted, it is understood that it is substituted with deuterium, tritium, a halogen, an alkyl group having 1 to 50 carbon atoms, or an alkoxy group having 1 to 50 carbon atoms.

[0019] An aromatic group refers to a hydrocarbon group containing at least one aromatic ring. A heterocyclic group refers to a cyclic hydrocarbon group formed by replacing at least one carbon atom in a carbon ring with a heteroatom. The heterocyclic groups mentioned in the embodiments of the present application can be aliphatic heterocyclic groups or heteroaromatic groups. Aliphatic heterocyclic groups are those in which the heterocyclic ring in the molecular skeleton does not exhibit aromaticity, while heterocyclic groups with properties similar to benzene are heteroaromatic groups. A heteroaromatic group refers to an aromatic hydrocarbon group containing at least one heteroatom. The heteroatom is preferably selected from Si, N, P, O, S and / or Ge, and is particularly preferably selected from Si, N, P, O and / or S.

[0020] The general structural formula of the heterospirocyclic compound provided in the examples of the present application is shown in formula (I):

[0021] Wherein, X1 is selected from O or N.

[0022] When X1 is selected from O, Z is selected from non-bonding, and one of Y1 and Y2 is selected from -Se-, -Te-, -CC-, -C=C-, The other is selected from non-bonding, single bond, -O-, -S-, -Se-, -Te-, -CC-, -C=C-,

[0023] When X1 is selected from N, Z is selected from an aromatic or heterocyclic group having 4 to 50 carbon atoms and substituted or unsubstituted by deuterium, tritium, halogen, an alkyl group having 1 to 50 carbon atoms or an alkoxy group having 1 to 50 carbon atoms, and one of Y1 and Y2 can be selected from -O-, -S-, -O-, -S-, -Se-, -Te-, -CC-, -C=C-, The other can be selected from non-bonding, single bond, -O-, -S-, -Se-, -Te-, -CC-, -C=C-,

[0024] When X1 is selected from N, Z may or may not form a ring with A6. In some embodiments, Z may be connected to A6 via a single bond to form a ring.

[0025] R1-R 12 Each is independently selected from an aromatic group or a heterocyclic group having 4 to 50 carbon atoms, which is unsubstituted or substituted with deuterium, tritium, halogen, an alkyl group having 1 to 50 carbon atoms or an alkoxy group having 1 to 50 carbon atoms.

[0026] A1 to A6 are each independently selected from an aromatic group or heterocyclic group having 4 to 50 carbon atoms, which is unsubstituted or substituted with deuterium, tritium, halogen, an alkyl group having 1 to 50 carbon atoms, or an alkoxy group having 1 to 50 carbon atoms.

[0027] Boron and nitrogen compounds offer the advantages of narrow-band emission and high luminescence efficiency. The introduction of heteroatoms can effectively enhance spin-orbit coupling, speeding up intersystem crossing and reverse intersystem crossing, competing with non-radiative transition rates to improve luminescence efficiency. However, existing boron and nitrogen materials incorporate relatively few heteroatoms and heteroatom groups, resulting in limited improvements in material and device performance. These materials cannot meet the high efficiency and long lifetime requirements of commercial high-performance electroluminescent devices, nor can they meet the spectral matching and efficient energy transfer requirements of sensitized systems.

[0028] The boron nitrogen compound with the above structural formula (1) provided in the present application can be used as a red light emitting material. The introduction of different types of heteroatoms or heteroatom groups into its luminescent core can improve the luminescence efficiency of the material and reduce exciton dissipation. At the same time, by modifying the luminescent core plane of the boron nitrogen compound with weak electron-donating or weak electron-withdrawing groups, the charge transfer characteristics can be slightly adjusted to adjust the luminescence spectrum, thereby improving the luminescence efficiency and life of the electroluminescent device.

[0029] Optionally, the number of carbon atoms in the aromatic group or heterocyclic group mentioned in the embodiments of the present application can be further 4-30. Further, it can be 4-20. Further, it can be 1-18 or 4-14, or a value between any two of the above values.

[0030] Furthermore, when the aromatic group or heterocyclic group mentioned in the embodiments of the present application is substituted by an alkyl group or an alkoxy group, the number of carbon atoms of the alkyl group or the alkoxy group may be 1-30, 1-20, 3-20, 1-18, 1-15, 1-10, 1-8, etc., or a value between any two of the above values.

[0031] In some embodiments, each occurrence of the aromatic group or heterocyclic group is independently selected from any one of the following structural formulas 1-38:

[0032] Among them, L1-L 19 Each is independently selected from a straight-chain alkyl group or a branched-chain alkyl group having 1 to 50 carbon atoms, which is unsubstituted or substituted by deuterium, tritium, a halogen, an alkyl group having 1 to 50 carbon atoms, or an alkoxy group having 1 to 50 carbon atoms; or an aromatic group or a heterocyclic group having 4 to 50 carbon atoms, which is unsubstituted or substituted by deuterium, tritium, a halogen, an alkyl group having 1 to 50 carbon atoms, or an alkoxy group having 1 to 50 carbon atoms.

[0033] L1-L 19 They may or may not form a ring. In some embodiments, L1-L 19 They can be connected to each other through -O-, -S- or a single bond.

[0034] In some embodiments, A1-A6 are each independently selected from one of the following groups:

[0035] Among them, R 13 Selected from tert-butyl. "*" indicates the attachment site.

[0036] In some embodiments, X1 can be selected from O. Z can be selected from non-bonding. Y1 can be selected from -O-, -S-, -Se-, -Te-, -CC-, -C=C-, Y2 can be selected from non-bonding, single bond, -O-, -S-, -Se-, -Te-, -CC-, -C=C-, Wherein, R1-R6 can be selected from phenyl groups.

[0037] Furthermore, in some embodiments, the boron nitrogen compound is selected from one of the compounds shown in Formulas 1-1-1 to 13-9-1:

[0038] In some embodiments, X1 can be selected from N. Z can be selected from p-tert-phenyl. Y1 and Y2 can each independently be selected from -O-, -S-, -Se-, or -Te-. Z and A6 can form a ring or not.

[0039] Furthermore, in some embodiments, the boron nitrogen compound can be selected from one of the compounds shown in Formulas 1-1-2 to 4-4-2 and 1-1-3 to 4-4-3:

[0040] An embodiment of the present application further provides an electroluminescent device, comprising an anode, a cathode, and a light-emitting layer located between the anode and the cathode.

[0041] The material of the light-emitting layer may include the boron-nitrogen compound described in the above-mentioned embodiment. Boron-nitrogen compounds have the advantages of narrow-band emission and high luminous efficiency. The boron-nitrogen compounds described in the present embodiment can be used as red-light luminescent materials. By modifying the luminescent core plane of the boron-nitrogen compound with weak electron-donating or electron-withdrawing groups, the charge transfer characteristics can be slightly adjusted to tune the luminescent spectrum, thereby improving the luminous efficiency and lifespan of the electroluminescent device.

[0042] In some embodiments, the electroluminescent device further comprises a hole injection layer, a hole transport layer, and an electron blocking layer located between the anode and the light-emitting layer and sequentially stacked on the anode. The hole transport layer may be a multilayer composite film layer including a first hole transport layer and a second hole transport layer stacked together.

[0043] In some embodiments, the electroluminescent device further comprises an electron transport layer and an electron injection layer located between the light-emitting layer and the cathode and sequentially stacked on the light-emitting layer. The electron transport layer may be a multi-layer composite film layer including a stacked first electron transport layer and a second electron transport layer.

[0044] The electroluminescent device described in the present application can be selected from, but not limited to, organic light emitting diodes (OLEDs), organic photovoltaic cells, organic light emitting cells, organic field effect transistors, organic light emitting field effect transistors, organic lasers, organic spintronic devices, organic sensors and organic plasmon emission diodes, etc., with OLED being particularly preferred.

[0045] In an embodiment of the present application, the anode may include a conductive metal, a metal oxide, or a conductive polymer. The anode can easily inject holes into the hole injection layer, the hole transport layer, or the light emitting layer.

[0046] In some embodiments, examples of anode materials include, but are not limited to, Al, Cu, Au, Ag, Mg, Fe, Co, Ni, Mn, Pd, Pt, ITO, aluminum-doped zinc oxide (AZO), and the like. Other anode materials are known and can be readily selected and used by one of ordinary skill in the art. The anode material can be deposited using any suitable technique, such as a suitable physical vapor deposition method, including radio frequency magnetron sputtering, vacuum thermal evaporation, electron beam (e-beam), and the like.

[0047] In some embodiments, the anode is patterned. Patterned ITO conductive substrates are commercially available and can be used to prepare the electroluminescent device according to the present application.

[0048] In the present invention, the cathode may comprise a conductive metal or metal oxide, and may easily inject electrons into the electron injection layer or the electron transport layer or directly into the light emitting layer.

[0049] In principle, any material that can be used as a cathode in an OLED is suitable for use as the cathode material in the device of this application. Examples of cathode materials include, but are not limited to, Al, Au, Ag, Ca, Ba, Mg, LiF / Al, MgAg alloys, BaF2 / Al, Cu, Fe, Co, Ni, Mn, Pd, Pt, and ITO. The cathode material can be deposited using any suitable technique, such as physical vapor deposition (PVD), including radio frequency magnetron sputtering, vacuum thermal evaporation, and electron beam (e-beam).

[0050] The hole injection material, hole transport material, electron blocking material, electron transport material and electron injection material used in the electroluminescent device of the present application are not particularly limited, and any compound can be used as long as the compound is commonly used as a hole injection material, hole transport material, electron blocking material, electron transport material and electron injection material.

[0051] The present application also relates to applications of the electroluminescent device according to the present application in various electronic devices, including, but not limited to, display devices, lighting devices, light sources, sensors, and the like.

[0052] Embodiments of the present application also provide a display device, including but not limited to mobile phones, vehicle displays, wearable devices, AR (augmented reality), VR (virtual reality), laptop computers, televisions, etc.

[0053] Specific embodiments

[0054] The present application is described in detail below through specific examples. The following examples are only some examples of the present application and are not intended to limit the present application. The raw materials used in the following examples, unless otherwise specified, are all commercially available products. Among them, Pd2(dba)3: trisdibenzylideneacetone dipalladium; (t-Bu)3PHBF4: tri-tert-butylphosphine tetrafluoroborate; t-BuONa: sodium tert-butoxide; o-DCB: o-dichlorobenzene; Pd(OAc)2: palladium acetate; tolune: toluene; t-BuOK: potassium tert-butoxide; DMF: N,N-dimethylformamide; t-BuLi: tert-butyllithium; BBr3: boron tribromide; DIPEA: N,N-diisopropylethylamine; CuI: cuprous iodide; K2CO3: potassium carbonate; 1,4-dioxane: 1,4-dioxane; Pd(OAc)2: palladium acetate; Cs2CO3: cesium carbonate.

[0055] Example 1

[0056] The synthetic route of the target compound 1-1-1 of this embodiment is as follows:

[0057] Synthesis steps:

[0058] 1.1 Synthesis of Intermediate 1-1-1-a: 1,4-dibromo-2,5-difluorobenzene (16.3 g, 60 mmol), phenoselenazine (12.3 g, 50 mmol), trisdibenzylideneacetone dipalladium (1.9 g, 2 mmol), tri-tert-butylphosphine tetrafluoroborate (1.2 g, 4 mmol), sodium tert-butoxide (5.8 g, 60 mmol), and o-dichlorobenzene (150 mL) were added to a 500 mL round-bottom flask. The mixture was vacuumed and purged with argon for three cycles. The mixture was stirred at 130°C for 18 hours under an argon atmosphere. After cooling to room temperature, the mixture was poured into 150 mL of water and extracted with dichloromethane (150 mL × 3). The combined organic phases were washed twice with saturated brine (100 mL × 2). After removing the organic solvent by rotary evaporation, the crude product was purified by silica gel column chromatography using petroleum ether as eluent to obtain 17.05 g of intermediate 1-1-1-a with a yield of 78%.

[0059] 1.2 Synthesis of intermediate 1-1-1-b: Intermediate 1-1-1-a (17.05 g, 39 mmol), diphenylamine (6.6 g, 39 mmol), palladium acetate (0.2 g, 1 mmol), tri-tert-butylphosphine tetrafluoroborate (0.87 g, 3 mmol), sodium tert-butoxide (3.8 g, 40 mmol) and toluene (120 mL) were added to a 500 mL Schlenk flask, and the vacuum argon gas step was cycled three times. The mixture was stirred at 110 ° C. under argon protection for 12 hours. After cooling to room temperature, the mixture was poured into 150 mL of water and then extracted with dichloromethane (150 mL × 3). The combined organic phase was washed twice with saturated brine (100 mL × 2). After removing the organic solvent by rotary evaporation, the product was purified by silica gel column chromatography using petroleum ether / dichloromethane (V / V=8 / 1) as eluent to obtain 17.8 g of 1-1-1-b with a yield of 87%.

[0060] 1.3 Synthesis of Intermediate 1-1-1-c: Intermediate 1-1-1-b (17.8 g, 34 mmol), phenol (7.5 g, 80 mmol), potassium tert-butoxide (9.0 g, 80 mmol), and N,N-dimethylformamide (100 mL) were added to a 250 mL round-bottom flask. After three cycles of evacuation and purging with argon, the mixture was stirred at 150°C under an argon atmosphere for 12 hours. After cooling to room temperature, the mixture was poured into 150 mL of water and extracted with dichloromethane (150 mL x 3). The combined organic phases were washed twice with saturated brine (100 mL x 2). After removing the organic solvent by rotary evaporation, the crude product was purified by silica gel column chromatography using petroleum ether / dichloromethane (v / v = 8 / 1) as the eluent to obtain 18.3 g of Intermediate 1-1-1-c in 80% yield.

[0061] 1.4 Synthesis of Target Compound 1-1-1: Intermediate 1-1-1-c (13.5 g, 20 mmol) was added to a 500 mL Schlenk flask and the reaction was repeated three times with evacuation and argon purging. Ultra-dry o-dichlorobenzene (180 mL) was then added. Under argon, the mixture was cooled in an ice bath for 10 minutes. Boron tribromide (3.9 mL, 40 mmol) was then quickly added. Stirred in an ice bath until exotherm subsided. The reaction was then heated to 120°C and stirred for 48 hours. After cooling to room temperature, N,N-diisopropylethylamine (8 mL, 46 mmol) was added in an ice bath. Stirred at room temperature until exotherm subsided. The mixture was heated to 100°C in the dark and stirred at this temperature for 6 hours. After the reaction was complete, the mixture was cooled to room temperature and poured into 150 mL of water, followed by extraction with dichloromethane (150 mL x 3). The combined organic phases were washed twice with saturated brine (100 mL x 2). After removing the organic solvent by rotary evaporation, the product was slowly purified by chromatography on a silica gel column using petroleum ether / dichloromethane (V / V=9 / 1) as eluent to obtain 4.83 g of the target compound 1-1-1 with a reaction yield of 35%.

[0062] Example 2

[0063] The synthetic route of the target compound 2-1-1 of this embodiment is as follows:

[0064] Synthesis steps:

[0065] 2.1 Synthesis of Intermediate 2-1-1-a: 1-Bromo-2,5-difluoro-4-iodobenzene (21.4 g, 55 mmol), 3,6-di-tert-butylcarbazole (14.0 g, 50 mmol), copper powder (0.32 g, 5 mmol), iodide (0.019 g, 1 mmol), potassium carbonate (8.3 g, 60 mmol) and 1,4-dioxane (150 mL) were added to a 500 mL round-bottom flask. The evacuation and argon gas flow steps were cycled three times and stirred at 90 ° C for 18 hours under argon atmosphere. After cooling to room temperature, the mixture was poured into 150 mL of water and then extracted with dichloromethane (150 mL × 3). The combined organic phase was washed twice with saturated brine (100 mL × 2). After removing the organic solvent by rotary evaporation, the crude product was purified by silica gel column chromatography using petroleum ether as eluent to obtain 20.5 g of intermediate 2-1-1-a with a yield of 87%.

[0066] 2.2 Synthesis of Intermediate 2-1-1-b: 2-1-1-a (20.5 g, 43.5 mmol), phenoselenazine (10.8 g, 44 mmol), trisdibenzylideneacetone dipalladium (1.9 g, 2 mmol), tri-tert-butylphosphine tetrafluoroborate (1.2 g, 4 mmol), sodium tert-butoxide (3.8 g, 40 mmol), and toluene (120 mL) were added to a 500 mL Schlenk flask. The evacuation and argon gas flow steps were cycled three times, and the mixture was stirred at 110°C under argon protection for 12 hours. After cooling to room temperature, the mixture was poured into 150 mL of water and extracted with dichloromethane (150 mL × 3). The combined organic phases were washed twice with saturated brine (100 mL × 2). After removing the organic solvent by rotary evaporation, the product was purified by silica gel column chromatography using petroleum ether / dichloromethane (V / V=10 / 1) as eluent to obtain 18.8 g of intermediate 2-1-1-b with a yield of 68%.

[0067] 2.3 Synthesis of Intermediate 2-1-1-c: Intermediate 2-1-1-b (18.4 g, 29 mmol), phenol (6.6 g, 70 mmol), potassium tert-butoxide (8.4 g, 75 mmol), and N,N-dimethylformamide (90 mL) were added to a 250 mL round-bottom flask. After three cycles of evacuation and purging with argon, the mixture was stirred at 150°C under an argon atmosphere for 12 hours. After cooling to room temperature, the mixture was poured into 150 mL of water and extracted with dichloromethane (150 mL × 3). The combined organic phases were washed twice with saturated brine (100 mL × 2). After removing the organic solvent by rotary evaporation, the crude product was purified by silica gel column chromatography using petroleum ether / dichloromethane (V / V = 9 / 1) as the eluent to obtain 17.3 g of Intermediate 2-1-1-c with a yield of 76%.

[0068] 2.4 Synthesis of Target Compound 2-1-1: Intermediate 2-1-1-c (15.7 g, 20 mmol) was placed in a 500 mL Schlenk flask and the evacuation and argon-gas cycle was repeated three times. Ultra-dry o-dichlorobenzene (180 mL) was then added. Under argon protection, the mixture was cooled in an ice bath for 10 minutes. Boron tribromide (3.9 mL, 40 mmol) was then quickly added and stirred at 120°C for 48 hours. After cooling to room temperature, N,N-diisopropylethylamine (7 mL, 40 mmol) was added in an ice bath. Stirring continued until heat dissipated. The mixture was heated to 60°C in the dark and stirred at this temperature for 48 hours. After the reaction was complete, the mixture was cooled to room temperature and poured into 150 mL of water, followed by extraction with dichloromethane (150 mL x 3). The combined organic phases were washed twice with saturated brine (100 mL x 2). After removing the organic solvent by rotary evaporation, the product was slowly purified by chromatography on a silica gel column using petroleum ether / dichloromethane (V / V=9 / 1) as eluent to obtain 4.3 g of the target compound 2-1-1 with a reaction yield of 27%.

[0069] Example 3

[0070] The synthetic route of the target compound 1-1-2 of this embodiment is as follows:

[0071] Synthesis steps:

[0072] 3.1 Synthesis of Intermediate 1-1-2-a: 1,4-Dibromo-2,5-difluorobenzene (13.6 g, 50 mmol), phenoxazine (18.3 g, 100 mmol), palladium acetate (0.9 g, 4 mmol), tri-tert-butylphosphine tetrafluoroborate (3.5 g, 12 mmol), sodium tert-butoxide (14.4 g, 150 mmol), and toluene (150 mL) were added to a 500 mL round-bottom flask. The mixture was vacuumed and purged with argon three times. Stir at 80°C under an argon atmosphere for 18 hours. After cooling to room temperature, the mixture was poured into 150 mL of water and extracted with dichloromethane (150 mL x 3). The combined organic phases were washed twice with saturated brine (100 mL x 2). After removing the organic solvent by rotary evaporation, the crude product was purified by silica gel column chromatography using petroleum ether as eluent to obtain 19.3 g of intermediate 1-1-2-a with a yield of 81%.

[0073] 3.2 Synthesis of Intermediate 1-1-2-b: 1-1-2-a (19.3 g, 40.5 mmol), 3,6-di-tert-butylcarbazole (11.5 g, 41 mmol), cesium carbonate (13.7 g, 42 mmol), and N,N-dimethylformamide (180 mL) were added to a 500 mL Schlenk flask and the vacuum and argon flow steps were cycled three times. The mixture was stirred at 100°C under argon protection for 12 hours. After cooling to room temperature, the mixture was poured into 150 mL of water and extracted with dichloromethane (150 mL × 3). The combined organic phases were washed twice with saturated brine (100 mL × 2). After removing the organic solvent by rotary evaporation, the product was purified by silica gel column chromatography using petroleum ether / dichloromethane (V / V = 6 / 1) as the eluent to obtain 24.4 g of Intermediate 1-1-2-b with a yield of 82%.

[0074] 3.3 Synthesis of Intermediate 1-1-2-c: Intermediate 1-1-2-b (24.3 g, 33 mmol), phenol (3.8 g, 40 mmol), potassium tert-butoxide (4.5 g, 40 mmol), and N,N-dimethylformamide (100 mL) were added to a 250 mL round-bottom flask. After three cycles of evacuation and purging with argon, the mixture was stirred at 150°C under an argon atmosphere for 12 hours. After cooling to room temperature, the mixture was poured into 150 mL of water and extracted with dichloromethane (150 mL x 3). The combined organic phases were washed twice with saturated brine (100 mL x 2). After removing the organic solvent by rotary evaporation, the crude product was purified by silica gel column chromatography using petroleum ether / dichloromethane (v / v = 7 / 1) as the eluent to obtain 20.8 g of Intermediate 1-1-2-c with a yield of 78%.

[0075] 3.4 Synthesis of Target Compound 1-1-2: Intermediate 1-1-2-c (16.2 g, 20 mmol) was added to a 500 mL Schlenk flask. The mixture was evacuated and purged with argon three times, followed by the addition of ultra-dry mesitylene (180 mL). Under argon, the mixture was cooled in an ice bath for 10 minutes. Boron tribromide (3.9 mL, 40 mmol) was then quickly added. The mixture was stirred in an ice bath until exotherm dissipated. The mixture was then heated to 120°C and stirred for 48 hours. After cooling to room temperature, N,N-diisopropylethylamine (7 mL, 40 mmol) was added in an ice bath. The mixture was stirred at room temperature for 3 minutes until exotherm dissipated. The mixture was then heated to 100°C and stirred at this temperature for 48 hours, shielded from light. After the reaction was complete, the mixture was cooled to room temperature and poured into 150 mL of water, followed by extraction with dichloromethane (150 mL x 3). The combined organic phases were washed twice with saturated brine (100 mL x 2). After removing the organic solvent by rotary evaporation, the product was slowly purified by chromatography on a silica gel column using petroleum ether / dichloromethane (V / V=9 / 1) as eluent to obtain 4.1 g of the target compound 1-1-2 with a yield of 25%.

[0076] Example 4

[0077] The synthetic route of the target compound 3-3-2 of this embodiment is as follows:

[0078] Synthesis steps:

[0079] In the synthesis of intermediate 1-1-2-a of Example 3, phenoxazine was replaced with pheneselenazine (24.6 g, 100 mmol), and palladium acetate was replaced with trisdibenzylideneacetone dipalladium (3.8 g, 4 mmol). The other steps were the same as in Example 3. After the synthesis, 3.8 g of the target compound 3-3-2 was obtained with a yield of 8%.

[0080] Example 5

[0081] The synthetic route of the target compound 1-1-3 of this embodiment is as follows:

[0082] Synthesis steps:

[0083] The tert-butylcarbazole in the synthesis of the intermediate 1-1-2-b of Example 3 was replaced with tert-butyldiphenylamine (25.1 g, 100 mmol) and the reaction temperature was increased to 180°C. The other steps were the same as in Example 3. After the final synthesis, 2.0 g of the target compound 1-1-3 was obtained with a yield of 5%.

[0084] The mass spectrometry (MS) and elemental analysis (EA) results of the target compounds 1-1-1, 2-1-1, 1-1-2, 3-3-2, and 1-1-3 synthesized in Example 1-7 are shown in Table 1 below.

[0085] Table 1

[0086] The performance of the electroluminescent device including the above-mentioned compound is tested through a specific device embodiment. Among them, the schematic diagram of the film stack structure of the electroluminescent device is shown in Figure 1, wherein: 1 - glass and conductive glass (ITO anode) substrate layer (commercially available); 2 - hole injection layer (HAT-CN, 5nm); 3 - first hole transport layer (TAPC, 30nm); 4 - second hole transport layer (TCTA, 15nm); 5 - electron blocking layer (mCBP, 10nm); 6 - light-emitting layer (the compound synthesized in the above Examples 1-5 of the present application or the compound A shown in the following structure is evaporated with the DMIC-TRZ host and the phosphorescent sensitizer Ir(mphmq)2tmd in a ratio of 2:189:9, 20nm); 7 - first electron transport layer (POT2T, 20nm); 8 - second electron transport layer (ANT-BIZ, 30nm); 9 - electron injection layer (Liq, 2nm); 10 - cathode (Al, 100nm).

[0087] The electroluminescent device can be manufactured according to methods known in the art, such as the method disclosed in reference (DOI: 10.1039 / d3mh00800b). The specific method is as follows: under high vacuum conditions, the hole injection layer, hole transport layer, light-emitting layer, electron transport layer, electron injection layer and cathode are sequentially deposited on a cleaned conductive glass (ITO) substrate. The device shown in Figure 1 is manufactured using this method. At a current density of 10 mA / cm 2 The luminescence characteristics of the prepared devices were recorded under the following conditions, as shown in Table 2. The preparation processes and structures of Comparative Example 1 and Examples 1-5 were the same, except that the materials of the light-emitting layers were different. The materials of the light-emitting layer of OLED-Ref were compound A, DMIC-TRZ host, and phosphorescent sensitizer Ir(mphmq)2tmd in a ratio of 2:189:9; the material of the light-emitting layer of OLED-1 was compound 1-1-1; the material of the light-emitting layer of OLED-2 was compound 2-1-1; the material of the light-emitting layer of OLED-3 was compound 1-1-2; the material of the light-emitting layer of OLED-4 was compound 3-3-2; and the material of the light-emitting layer of OLED-5 was compound 1-1-3.

[0088] Table 2

[0089] As can be seen from Table 2, the external quantum efficiency (EQE) and lifespan of the electroluminescent devices prepared in device examples 1-5 provided in the examples of the present application are improved compared to the electroluminescent device prepared in device comparative example 1. The possible reason is that the luminescent core of the boron nitrogen compound provided in the examples of the present application introduces different types of heteroatoms or heteroatom groups, which improves the luminous efficiency of the material and reduces exciton dissipation. At the same time, weak electron donating or weak electron withdrawing groups are added to the luminescent core plane of the boron nitrogen compound to slightly adjust the charge transfer characteristics to adjust the luminescence spectrum, thereby improving the efficiency and lifespan of the electroluminescent device and producing a high-efficiency red electroluminescent device.

[0090] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0091] The above is a detailed description of a boron-nitrogen compound, an electroluminescent device, and a display device provided in the embodiments of the present application. The above description is only used to help understand the technical solution and its core idea of ​​the present application; ordinary technicians in this field can modify the technical solutions recorded in the aforementioned embodiments or replace some of the technical features therein with equivalents, which does not cause the essence of the corresponding technical solution to deviate from the scope of the technical solution of the embodiments of the present application.

Claims

1. A boron-nitrogen compound, wherein: The general structural formula of the boron-nitrogen compound is shown in formula (I): wherein X1 is selected from O or N; When X1 is selected from O, Z is selected from non-bonding, and one of Y1 and Y2 is selected from -O-, -S-, -Se-, -Te-, -CC-, -C=C-, The other is selected from non-bonding, single bond, -O-, -S-, -Se-, -Te-, -CC-, -C=C-, When X1 is selected from N, Z is selected from an aromatic or heterocyclic group having 4 to 50 carbon atoms and substituted or unsubstituted with deuterium, tritium, halogen, an alkyl group having 1 to 50 carbon atoms or an alkoxy group having 1 to 50 carbon atoms, and one of Y1 and Y2 is selected from -O-, -S-, -Se-, -Te-, -CC-, -C=C-, The other is selected from non-bonding, single bond, -O-, -S-, -Se-, -Te-, -CC-, -C=C-, Z and A6 form a ring or not; R1 to R 12 Each independently selected from aromatic groups or heterocyclic groups having 4 to 50 carbon atoms, substituted or unsubstituted with deuterium, tritium, halogen, alkyl groups having 1 to 50 carbon atoms, or alkoxy groups having 1 to 50 carbon atoms group; A1 to A6 are each independently selected from an aromatic group or heterocyclic group having 4 to 50 carbon atoms, which is unsubstituted or substituted with deuterium, tritium, halogen, an alkyl group having 1 to 50 carbon atoms, or an alkoxy group having 1 to 50 carbon atoms.

2. The boron nitrogen compound according to claim 1, wherein The aromatic group or heterocyclic group has 4 to 30 carbon atoms.

3. The boron nitrogen compound according to claim 1, wherein Each occurrence of the aromatic group or heterocyclic group is independently selected from one of the following structural formulas 1-38: Among them, L1 to L 19 Each is independently selected from a linear or branched alkyl group having 1 to 50 carbon atoms, which is unsubstituted or substituted by deuterium, tritium, halogen, an alkyl group having 1 to 50 carbon atoms, or an alkoxy group having 1 to 50 carbon atoms; or an aromatic group or heterocyclic group having 4 to 50 carbon atoms, which is unsubstituted or substituted by deuterium, tritium, halogen, an alkyl group having 1 to 50 carbon atoms, or an alkoxy group having 1 to 50 carbon atoms; L1 to L 19 They may or may not form a ring with each other.

4. The boron nitrogen compound according to claim 2, wherein A1 to A6 are each independently selected from one of the following groups: Among them, R 13 selected from tert-butyl; "*" indicates the attachment site.

5. The boron nitrogen compound according to claim 4, wherein X1 is selected from O; Z is selected from non-bonding; Y1 is selected from -O-, -S-, -Se-, -Te-, -CC-, -C=C-, Y2 is selected from non-bonding, single bond, -O-, -S-, -Se-, -Te-, -CC-, -C=C-, R1-R6 are selected from phenyl groups.

6. The boron nitrogen compound according to claim 5, wherein the boron nitrogen compound is selected from one of the compounds shown in Formulas 1-1-1 to 13-9-1:

7. The boron nitrogen compound according to claim 4, wherein X1 is selected from N; Z is selected from p-tert-phenyl; Y1 and Y2 are each independently selected from -O-, -S-, -Se-, -Te-; Z and A6 may form a ring or not.

8. The boron nitrogen compound according to claim 7, wherein The boron nitrogen compound is selected from one of the compounds shown in Formulas 1-1-2 to 4-4-2 and 1-1-3 to 4-4-3:

9. An electroluminescent device, wherein: The invention comprises an anode and a cathode, and a light-emitting layer located between the anode and the cathode, wherein the light-emitting layer comprises a boron nitrogen compound, wherein the general structural formula of the boron nitrogen compound is shown in formula (I): wherein X1 is selected from O or N; When X1 is selected from O, Z is selected from non-bonding, and one of Y1 and Y2 is selected from -O-, -S-, -Se-, -Te-, -CC-, -C=C-, The other is selected from non-bonding, single bond, -O-, -S-, -Se-, -Te-, -CC-, -C=C-, When X1 is selected from N, Z is selected from an aromatic or heterocyclic group having 4 to 50 carbon atoms and substituted or unsubstituted with deuterium, tritium, halogen, an alkyl group having 1 to 50 carbon atoms or an alkoxy group having 1 to 50 carbon atoms, and one of Y1 and Y2 is selected from -O-, -S-, -Se-, -Te-, -CC-, -C=C-, The other is selected from non-bonding, single bond, -O-, -S-, -Se-, -Te-, -CC-, -C=C-, Z and A6 form a ring or not; R1 to R 12 Each is independently selected from an aromatic group or heterocyclic group having 4 to 50 carbon atoms, which is substituted or unsubstituted with deuterium, tritium, halogen, an alkyl group having 1 to 50 carbon atoms, or an alkoxy group having 1 to 50 carbon atoms; A1 to A6 are each independently selected from deuterated, tritium, halogen, alkyl or carbon atom having 1 to 50 carbon atoms. an alkoxy group having 1 to 50 carbon atoms, which may be substituted or unsubstituted, and an aromatic group or heterocyclic group having 4 to 50 carbon atoms.

10. The electroluminescent device according to claim 9, wherein The aromatic group or heterocyclic group has 4 to 30 carbon atoms.

11. The electroluminescent device according to claim 9, wherein Each occurrence of the aromatic group or heterocyclic group is independently selected from one of the following structural formulas 1-38: Among them, L1 to L 19 Each is independently selected from a linear or branched alkyl group having 1 to 50 carbon atoms, which is unsubstituted or substituted by deuterium, tritium, halogen, an alkyl group having 1 to 50 carbon atoms, or an alkoxy group having 1 to 50 carbon atoms; or an aromatic group or heterocyclic group having 4 to 50 carbon atoms, which is unsubstituted or substituted by deuterium, tritium, halogen, an alkyl group having 1 to 50 carbon atoms, or an alkoxy group having 1 to 50 carbon atoms; L1 to L 19 They may or may not form a ring with each other.

12. The electroluminescent device according to claim 10, wherein A1 to A6 are each independently selected from one of the following groups: Among them, R 13 selected from tert-butyl; "*" indicates the attachment site.

13. The electroluminescent device according to claim 12, wherein X1 is selected from O; Z is selected from non-bonding; Y1 is selected from -O-, -S-, -Se-, -Te-, -CC-, -C=C-, Y2 is selected from non-bonding, single bond, -O-, -S-, -Se-, -Te-, -CC-, -C=C-, R1 to R6 are selected from phenyl groups.

14. The electroluminescent device according to claim 13, wherein the boron nitrogen compound is selected from one of the compounds represented by formulas 1-1-1 to 13-9-1:

15. The electroluminescent device according to claim 12, wherein X1 is selected from N; Z is selected from p-tert-phenyl; Y1 and Y2 are each independently selected from -O-, -S-, -Se-, -Te-; Z and A6 may form a ring or not.

16. The electroluminescent device according to claim 15, wherein The boron nitrogen compound is selected from one of the compounds shown in Formulas 1-1-2 to 4-4-2 and 1-1-3 to 4-4-3:

17. A display device, wherein: The invention comprises an electroluminescent device, wherein the electroluminescent device comprises an anode and a cathode, and a light-emitting layer located between the anode and the cathode, wherein the light-emitting layer comprises a boron nitrogen compound, wherein the general structural formula of the boron nitrogen compound is as shown in formula (I): wherein X1 is selected from O or N; When X1 is selected from O, Z is selected from non-bonding, and one of Y1 and Y2 is selected from -O-, -S-, -Se-, -Te-, -CC-, -C=C-, The other is selected from non-bonding, single bond, -O-, -S-, -Se-, -Te-, -CC-, -C=C-, When X1 is selected from N, Z is selected from an aromatic or heterocyclic group having 4 to 50 carbon atoms and substituted or unsubstituted with deuterium, tritium, halogen, an alkyl group having 1 to 50 carbon atoms or an alkoxy group having 1 to 50 carbon atoms, and one of Y1 and Y2 is selected from -O-, -S-, -Se-, -Te-, -CC-, -C=C-, The other is selected from non-bonding, single bond, -O-, -S-, -Se-, -Te-, -CC-, -C=C-, Z and A6 form a ring or not; R1 to R 12 Each is independently selected from an aromatic group or heterocyclic group having 4 to 50 carbon atoms, which is substituted or unsubstituted with deuterium, tritium, halogen, an alkyl group having 1 to 50 carbon atoms, or an alkoxy group having 1 to 50 carbon atoms; A1 to A6 are each independently selected from deuterated, tritium, halogen, alkyl or carbon atom having 1 to 50 carbon atoms. an alkoxy group having 1 to 50 carbon atoms, or an unsubstituted aromatic group or heterocyclic group having 4 to 50 carbon atoms.

18. The display device according to claim 17, wherein: Each occurrence of the aromatic group or heterocyclic group is independently selected from any one of the following structural formulas 1-38: Among them, L1 to L 19 Each is independently selected from a linear or branched alkyl group having 1 to 50 carbon atoms, which is unsubstituted or substituted by deuterium, tritium, halogen, an alkyl group having 1 to 50 carbon atoms, or an alkoxy group having 1 to 50 carbon atoms; or an aromatic group or heterocyclic group having 4 to 50 carbon atoms, which is unsubstituted or substituted by deuterium, tritium, halogen, an alkyl group having 1 to 50 carbon atoms, or an alkoxy group having 1 to 50 carbon atoms; L1 to L 19 They may or may not form a ring with each other.

19. The display device according to claim 17, wherein: A1 to A6 are each independently selected from one of the following groups: Among them, R 13 selected from tert-butyl; "*" indicates the attachment site.

20. The display device according to claim 17, wherein X1 is selected from O; Z is selected from non-bonding; Y1 is selected from -O-, -S-, -Se-, -Te-, -CC-, -C=C-, Y2 is selected from non-bonding, single bond, -O-, -S-, -Se-, -Te-, -CC-, -C=C-, R1-R6 are selected from phenyl; and / or X1 is selected from N; Z is selected from p-tert-phenyl; Y1 and Y2 are each independently selected from -O-, -S-, -Se-, -Te-; Z and A6 form a ring or a non-ring.

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