Organic electroluminescent material containing boron core acceptor and application thereof in light-emitting device

Abstract

The application relates to an organic electroluminescent material containing a boron core acceptor and application thereof in a light-emitting device, and belongs to the technical field of organic electroluminescent materials. In the design of the molecule, heavy atoms such as sulfur and selenium are embedded into a nitrogen-containing aromatic hydrocarbon skeleton, the heavy atom effect is utilized to accelerate the exciton anti-inter-system crossing process. Meanwhile, due to the electron-deficient nature of boron atoms, oxygen and sulfur elements are used to bridge to form a boron-containing acceptor core with high fluorescence quantum efficiency. The boron-containing acceptor core is connected with a multiple resonance nitrogen-containing aromatic hydrocarbon skeleton to prepare a light-emitting material with the advantages of both types of TADF molecules. The light-emitting material is easy to synthesize and easy to form a film, and has the advantages of the charge transfer characteristics of both the multiple resonance type and the donor-acceptor type molecules. When the light-emitting material is used as a guest material to prepare a light-emitting layer of an organic electroluminescent device, a device with high efficiency and low efficiency roll-off is obtained.

Description

Technical Field

[0001] This invention belongs to the field of organic electroluminescent materials technology, specifically relating to an organic electroluminescent material containing boron nuclear acceptors and its application in light-emitting devices. Background Technology

[0002] Organic light-emitting diodes (OLEDs) are a new generation of display device technology. Since their inception, they have rapidly developed due to their advantages such as flexibility, wide viewing angle, self-emissiveness, and fast response speed. Organic electroluminescence technology can be mainly applied to lighting and displays. In the display field, OLEDs have achieved commercial production and become flagship products for various panel manufacturers. In the lighting field, because OLEDs can achieve a high degree of tunability in light color through the modification of organic molecules, representative products are gradually emerging in the market.

[0003] Organic light-emitting devices (OLEDs) consist of a functional layer and an emissive layer. The emissive layer typically comprises a host material and a guest material. The host material usually acts as a medium for energy transfer and prevents fluorescence aggregation and quenching due to excessive concentration, while the guest material is generally doped into the host material as a carrier of photon radiation. In terms of exciton utilization, traditional fluorescent materials can only utilize 25% of excitons, significantly reducing device efficiency. Second-generation phosphorescent materials, while utilizing all excitons, typically contain heavy metals such as platinum and iridium, resulting in high costs and hindering commercial production. New-generation thermally activated delayed fluorescence (TADF) materials achieve triplet exciton emission through reverse intergap crossing, and are typically composed of abundant and inexpensive elements such as C, H, O, and N, resulting in low cost. However, TADF-OLEDs often require balancing two conflicting aspects during molecular design: small singlet triplet energy level differences and large oscillator strength. Furthermore, device performance, such as brightness and lifetime, requires further optimization.

[0004] The emergence of TADF materials with a robust B / N polycyclic aromatic backbone has attracted considerable attention from researchers. Due to their multiple resonance properties, the highest energy occupied orbital (HOMO) and the lowest energy unoccupied orbital (LUMO) are confined to adjacent positions, resulting in very high fluorescence quantum efficiency (PLQY). Furthermore, the robust backbone also narrows the full width at half maximum (FWHM). In recent years, a robust polycyclic aromatic backbone with simple synthesis and high fluorescence quantum efficiency has emerged. This compound utilizes the electronegativity difference between N and C atoms to achieve multiple resonance properties, subsequently leading to the derivation of nitrogen-containing aromatic multiple resonance backbones such as indolocarbazole. However, TADF-OLEDs with multiple resonance properties typically exhibit large singlet triplet energy level differences, resulting in low backgap crossing rates for most of these compounds. Classical donor-acceptor TADF molecules, with their smaller singlet triplet energy level differences, could potentially benefit from improved backgap crossing rates if this characteristic could be applied to molecular design. Summary of the Invention

[0005] This invention synthesizes a novel boron-containing nuclear acceptor organic electroluminescent material by combining two highly rigid, multi-resonance parent nuclei. In molecule design, we chose to embed heavy atoms such as sulfur and selenium into a nitrogen-containing aromatic hydrocarbon framework, utilizing their heavy atom effect to accelerate the exciton antisystem crossing process. Meanwhile, due to the electron-deficient nature of boron atoms, many scientists have already used them as acceptors in organic electroluminescent devices, organic solar cells, and other fields. Here, we use a boron-containing acceptor nucleus with high fluorescence quantum efficiency, bridged by elements such as oxygen and sulfur, to connect the boron-containing acceptor nucleus with a multi-resonance nitrogen-containing aromatic hydrocarbon framework, creating a luminescent material that combines the advantages of both types of TADF molecules. It is easy to synthesize and form films, possessing the charge transfer characteristics of both multi-resonance and donor-acceptor molecules. As a guest material for the luminescent layer of organic electroluminescent devices, it yields devices with high efficiency and low efficiency roll-off.

[0006] The boron-containing nuclear acceptor organic electroluminescent material of the present invention has a general structural formula as shown in one of I, II, and III:

[0007]

[0008] A、A 1 They may be the same or different, and are independently selected from oxygen, sulfur, selenium, or sulfonyl groups;

[0009] X is independently selected from CR 1 2. Oxygen, sulfur, selenium, carbonyl or sulfonyl groups;

[0010] R, R 1 Each is independently selected from substituted or unsubstituted C1 to C1. 10 Alkyl, substituted or unsubstituted C6-C 30Aryl, substituted or unsubstituted C3-C 30 heteroaryl; substituents selected from C1 to C2. 10 Alkyl, C6-C 30 Aryl, C3~C 30 Mixed aromatic compounds.

[0011] Furthermore, R is independently selected from C1-C4 alkyl, substituted or unsubstituted C6-C4 alkyl groups. 30 Aryl, and more preferably methyl, isopropyl, tert-butyl or phenyl;

[0012] Furthermore, R 1 Independently selected from C1-C4 alkyl, substituted or unsubstituted C6-C 30 Aryl, and more preferably methyl or m-xylyl.

[0013] Furthermore, the structural formula of the boron-containing nuclear acceptor organic electroluminescent material of the present invention is shown in one of the following:

[0014]

[0015]

[0016]

[0017]

[0018]

[0019]

[0020] Compared with existing light-emitting device technologies, the advantages of this invention are as follows: the boron-containing nuclear acceptor organic electroluminescent material described in this invention can not only be used as a guest material for the emitting layer to prepare doped devices, but also directly as the emitting layer to prepare undoped devices, both achieving excellent photoelectric properties; due to the presence of heavy atoms, the exciton antisystem crossover is faster, resulting in high efficiency for this type of electroluminescent device, and the efficiency roll-off at high brightness is well suppressed. The synthesis of this type of compound is simple, and the preparation process is convenient. Compared with existing light-emitting devices, the maximum brightness, external quantum efficiency, current efficiency, and power efficiency of the device are significantly improved. Detailed Implementation

[0021] The present invention will be illustrated below with several specific embodiments. The compounds in the following embodiments can be synthesized with reference to the specific synthetic methods shown below. However, it should be noted that the route to obtain the target molecule is not limited to the synthetic methods and raw materials used in the present invention, and those skilled in the art can also select other methods or routes to obtain the novel compounds proposed in the present invention. Compounds for which synthetic methods are not mentioned in the present invention are all raw material products obtained through commercial means, or self-made using these raw material products according to known methods.

[0022] Example 1: Synthesis of Compound 1

[0023]

[0024] Synthesis of intermediate 1-1

[0025] Under nitrogen protection at room temperature, 8.8g of raw material was... 31.2 mmol), 4.05 g 1,5-dibromo-2,4-difluorobenzene (14.9 mmol), tris(dibenzylacetone)dipalladium-chloroform complex (0.9 mmol), 0.6 g (2-biphenyl)di-tert-butylphosphine (2 mmol), 4.5 g sodium tert-butoxide (45 mmol), and toluene (150 mL) were added to a 250 mL three-necked flask and heated under reflux overnight. The reaction mixture was cooled to room temperature, filtered, and the filtrate was concentrated with silica gel. After column chromatography (PE:EA = 80:1, v / v), recrystallization from dichloromethane / petroleum ether gave 7.74 g of a white solid (71% yield).

[0026] Synthesis of intermediates 1-2

[0027] Under nitrogen protection at room temperature, 7.7 g of intermediate 1-1 (10 mmol), 0.2 g of Pd(OAc)2 (0.9 mmol), 0.53 g of PPh3 (2 mmol), 1.14 g of triethylbenzylammonium chloride (5 mmol), 2.76 g of K2CO3 (20 mmol), and N,N-dimethylacetamide (150 mL) were added to a 250 mL three-necked flask and the mixture was heated under reflux overnight. After the reaction was completed and cooled to room temperature, the solution was concentrated by rotary evaporation, extracted with dichloromethane and water, concentrated with silica gel, and then subjected to column chromatography (DCM:EA = 1:4, v / v). Recrystallization from dichloromethane / petroleum ether yielded 5.6 g of a white solid (85% yield).

[0028] Synthesis of intermediates 1-3

[0029] In air, 6 g of intermediate 1-2 (8.4 mmol) was dissolved in 100 mL of dichloromethane. 2.99 g of NBS (16.8 mmol) was added in portions to the system, and the mixture was stirred overnight at room temperature. After the reaction was complete, water was added to quench the reaction. Extraction was performed, followed by extraction with dichloromethane and water. The organic layer was concentrated with silica gel, and then subjected to column chromatography (DCM:EA = 1:10, v / v). Recrystallization from dichloromethane / petroleum ether yielded 6.00 g of a white solid (90% yield).

[0030] Synthesis of Compound 1

[0031] Under nitrogen protection at room temperature, 2 g of intermediate 1-3 (2.53 mmol), 0.3 g of boron nucleoboron ester intermediate Pd(PPh)4 (0.25 mmol), 0.8 g of K2CO3 (5 mmol, aq, 2 mol / L), tetrahydrofuran, and water (100 mL) were added to a 250 mL three-necked flask and the mixture was heated under reflux overnight. The reaction solution was cooled to room temperature, concentrated by rotary evaporation, extracted with dichloromethane and water, concentrated with silica gel, and subjected to column chromatography (DCM:EA = 1:6, v / v). Recrystallization from dichloromethane / methanol yielded 0.8 g of a white solid (56% yield). Data on the obtained target compound are shown in Table 1.

[0032] Example 2: Synthesis of Compound 22

[0033]

[0034] Synthesis of intermediate 22-b

[0035] Under nitrogen protection at room temperature, 2.88 g of 4-methylphenol (26.7 mmol), 4.16 g of K₂CO₃ (30 mmol), and 7.26 g of 2,5-dibromo-1,3-difluorobenzene (26.7 mmol) were dissolved in 300 mL of N,N-dimethylformamide and added to a 500 mL three-necked flask. The mixture was heated under reflux overnight. After the reaction was complete, 1 L of water was added, and the precipitated product was filtered to obtain a solid. The solid was recrystallized from dichloromethane / methanol to give 8.94 g of a white solid (93% yield).

[0036] Synthesis of intermediate 22-c

[0037] Under nitrogen protection at room temperature, 3.22 g of 4-methylthiophenol (26.7 mmol), 4.16 g of K₂CO₃ (30 mmol), and 9.61 g of intermediate 22-b (26.7 mmol) were dissolved in 300 mL of N,N-dimethylformamide and added to a 500 mL three-necked flask. The mixture was heated under reflux overnight. After the reaction was complete, 1 L of water was added, and the precipitated product was filtered to obtain a solid. The solid was recrystallized from dichloromethane / methanol to give 11.77 g of a white solid (95% yield).

[0038] Synthesis of intermediate 22-d

[0039] Under nitrogen protection at room temperature, 11.61 g of intermediate 22-c (25 mmol) was dissolved in 300 mL of m-xylene, and the system was cooled to approximately -30 °C and maintained for 15 minutes. Then, 26 mmol (aq, 1.6 mol / L) of n-butyllithium dissolved in 12 mL of hexane was slowly injected into the system, and the system was maintained at approximately -30 °C for 1 hour. After adding 7.5 g of boron tribromide (30 mmol) under a nitrogen atmosphere at -30 °C, the system was raised to room temperature and maintained for 1 hour, then heated to 50 °C and reacted for 1 hour. After heating, the reaction flask was immersed in an ice-salt bath, and after the system temperature dropped to -5 °C and maintained for 15 minutes, 12 g of N,N'-diisopropylethylamine (50 mmol) was added, and the temperature was raised to 140 °C and refluxed overnight. After the reaction was completed and the solution was cooled to room temperature, the solution was concentrated by rotary evaporation, extracted with dichloromethane and water, concentrated with silica gel, and then subjected to column chromatography (DCM:EA = 1:5, volume ratio, the same below). The solution was then recrystallized from dichloromethane / petroleum ether to give 2.75 g of white solid (yield 28%).

[0040] Synthesis of intermediate 22-e

[0041] In an air environment, 7.08 g of intermediate 22-d (18 mmol) was dissolved in 150 mL of dichloromethane. The reaction flask was immersed in an ice-salt bath. After the system temperature dropped to -5 °C and was maintained for 15 minutes, 2.2 g of m-CPBA (36 mmol) was added to the system in multiple portions. After the addition was complete, the ice-salt bath was removed, and the mixture was heated to room temperature and stirred overnight. After the reaction was completed, the reaction was quenched with water, extracted, and then extracted with dichloromethane and water. The organic layer was concentrated with silica gel, and after column chromatography (DCM:EA = 1:5, volume ratio, the same below), the product was recrystallized from dichloromethane / petroleum ether to give 5.51 g of white solid (yield 72%).

[0042] Synthesis of intermediate 22-f

[0043] 3.06 g of intermediate 22-e (7.2 mmol), pinacol diboronate (5.2 g, 14.4 mmol), potassium acetate (4.9 g, 50 mmol), and [1,1'-bis(diphenylphosphine)ferrocene]palladium dichloride (0.11 g, 0.17 mmol) were added to a dry reaction flask equipped with a condenser. After three or more vacuum and nitrogen purging operations, the mixture was dissolved in 200 mL of dry dioxane. The reaction mixture was then heated to 100 °C and reacted for 12 h. After the reaction was completed, the reaction mixture was added to water, and the aqueous phase was extracted three times with dichloromethane (500 mL). The resulting dichloromethane phase was washed once with water and dried over anhydrous sodium sulfate. After removing dichloromethane by vacuum distillation, the crude product was washed twice with methanol to give 1.53 g of white solid (yield 45%).

[0044] Synthesis of Compound 22

[0045] Similar to the synthesis method of compound 1, using Compound 22 was prepared from the raw materials (yield 58%), and the relevant data of the target compound obtained are shown in Table 1.

[0046] Example 3: Synthesis of Compound 41

[0047]

[0048] Synthesis of Compound 41

[0049] Similar to the preparation method of intermediate 22-f (obtaining the intermediate from the same starting material through a similar reaction (without sulfonation)), intermediate 41-d was prepared, and then, similar to the synthesis method of compound 1, was used to... Compound 41 was prepared from the raw materials (yield 55%), and the relevant data of the target compound obtained are shown in Table 1.

[0050] Example 4: Synthesis of Compound 57

[0051]

[0052]

[0053] Synthesis of Compound 57

[0054] Similar to the preparation method of intermediate 22-f (obtaining intermediate from the same starting material through a similar reaction (without sulfonation)), intermediate 57-e was prepared, and then synthesized in a similar manner to compound 1. Compound 57 was prepared from the raw materials (yield 54%). The relevant data of the target compound obtained are shown in Table 1.

[0055] Example 5: Synthesis of Compound 87

[0056]

[0057]

[0058] Synthesis of Compound 87

[0059] Similar to the preparation method of intermediate 22-f (obtaining the intermediate from the same starting material through a similar reaction (without sulfonation)), intermediate 87-d was prepared, and then, similar to the synthesis method of compound 1, was used to... Compound 87 was prepared from the raw materials (yield 53%). The relevant data of the target compound obtained are shown in Table 1.

[0060] Example 6: Synthesis of Compound 108

[0061]

[0062]

[0063] Synthesis of Compound 108

[0064] Similar to the preparation method of intermediate 22-f (from the same starting material through a similar reaction, sulfonation yields the intermediate), intermediate 108-e was prepared, and then, similar to the synthesis method of compound 1, was used... Compound 108 was prepared from the raw materials (yield 56%). The relevant data of the target compound obtained are shown in Table 1.

[0065] Example 7: Synthesis of Compound 119

[0066]

[0067] Synthesis of Compound 119

[0068] Similar to the preparation method of intermediate 22-f (obtaining the intermediate from the same starting material through a similar reaction (without sulfonation)), intermediate 119-e was prepared, and then, similar to the synthesis method of compound 1, was used to... Compound 119 was prepared from the raw materials (yield 53%). The relevant data of the target compound obtained are shown in Table 1.

[0069] Example 8: Synthesis of Compound 141

[0070]

[0071] Synthesis of Compound 141

[0072] Similar to the preparation method of intermediate 22-f (obtaining the intermediate from the same starting material through a similar reaction (without sulfonation)), intermediate 141-d was prepared, and then, similar to the synthesis method of compound 1, was used to... Compound 141 was prepared from the raw material (yield 56%). The relevant data of the target compound obtained are shown in Table 1.

[0073] Example 9: Synthesis of Compound 161

[0074]

[0075]

[0076] Synthesis of Compound 161

[0077] Similar to the preparation method of intermediate 22-f (from the same starting material through a similar reaction, sulfonation yields the intermediate), intermediate 161-f was prepared, and then, similar to the synthesis method of compound 1, was used... Compound 141 was prepared from the raw materials (yield 57%). The relevant data of the target compound obtained are shown in Table 1.

[0078] Table 1: Summary of Product Data from Synthesis Examples

[0079] compound Molecular weight (m / Z) Elemental analysis (%) (C, H, N) Yield (%) Compound 1 756.18 C, 85.80; H, 4.95; N, 3.74 56 Compound 22 868.10 C, 74.73; H, 4.33; N, 3.25 58 Compound 41 956.25 C, 80.41; H, 5.54; N, 2.95 55 Compound 57 1404.54 C, 83.71; H, 6.64; N, 1.95 54 Compound 87 996.12 C, 65.37; H, 3.78; N, 2.85 53 Compound 108 896.15 C, 64.18; H, 2.84; N, 3.15 56 Compound 119 1128.36 C, 80.23; H, 5.44; N, 2.31 53 Compound 141 1463.81 C, 60.86; H, 3.47; N, 1.95 56 Compound 161 1291.86 C, 61.50; H, 2.69; N, 2.14 57

[0080] Device Examples

[0081] This invention provides an organic electroluminescent device comprising the compounds described in the above embodiments. OLEDs are used as examples of organic electroluminescent devices in the following illustrations; however, it should be noted that the following detailed descriptions are not intended to limit the invention, and those skilled in the art can extend these detailed descriptions to other organic electroluminescent devices.

[0082] OLEDs consist of an anode layer, an organic functional layer, and a cathode layer; the organic functional layer includes hole transport regions, light-emitting layers, electron transport regions, etc.

[0083] In specific embodiments, glass or polymer materials can be used as the substrate beneath the anode layer. Furthermore, thin-film transistors (TFTs) can also be incorporated into the substrate used for displays.

[0084] The anode layer material can be any combination of transparent conductive oxide materials such as indium tin oxide (ITO), indium zinc oxide (IZO), tin dioxide (SnO2), and zinc oxide (ZnO). The cathode layer material can also be any combination of metals or alloys such as magnesium (Mg), silver (Ag), aluminum (Al), aluminum-lithium (Al-Li), calcium (Ca), magnesium-indium (Mg-In), and magnesium-silver (Mg-Ag).

[0085] Organic functional layers can be formed through methods such as vacuum evaporation, spin coating, and printing.

[0086] The hole transport region located between the anode layer and the light-emitting layer can be a single-layer hole transport layer (HTL), including a single-layer hole transport layer containing only one compound and a single-layer hole transport layer containing multiple compounds; the hole transport region can also be a combination of a hole injection layer (HIL) and a hole transport layer (HTL).

[0087] The hole injection layer (HIL) is a host-guest doped material. The host material is selected from HT-1 to HT-30, and the guest material is selected from HI1 to HI3. The doping ratio of the guest material in the host-guest material is 3 to 5 wt%.

[0088]

[0089] The material of the hole transport layer (HTL) may be selected from, but is not limited to, phthalocyanine derivatives such as CuPc, conductive polymers or polymers containing conductive dopants such as polyphenylene ethylene, polyaniline / dodecylbenzenesulfonic acid (PANI / DBSA), poly(3,4-ethylenedioxythiophene) / poly(4-styrenesulfonate) (PEDOT / PSS), polyaniline / camphorsulfonic acid (PANI / CSA), polyaniline / poly(4-styrenesulfonate) (Pani / PSS), aromatic amine derivatives such as HT-1 to HT-30, or any combination thereof.

[0090]

[0091]

[0092] The emissive layer consists of luminescent dyes (i.e., dopants) that can emit different wavelengths of light, and a host material. The emissive layer can be a monochromatic emissive layer emitting a single color such as red, green, or blue. Multiple monochromatic emissive layers of different colors can be arranged in a planar pattern according to pixel design, or they can be stacked together to form a colored emissive layer. When different colored emissive layers are stacked together, they can be separated from each other or connected to each other. The emissive layer can also be a single colored emissive layer that can simultaneously emit different colors such as red, green, and blue.

[0093] Depending on the technology used, the light-emitting layer material can be various, including fluorescent electroluminescent materials, phosphorescent electroluminescent materials, and thermally activated delayed fluorescence materials. An OLED device can employ a single light-emitting technology or a combination of different technologies. These different light-emitting materials, categorized by technology, can emit light of the same color or different colors.

[0094] In this invention, the light-emitting layer employs blue fluorescent electroluminescence technology. The host material of the light-emitting layer is selected from, but is not limited to, one or more combinations of BFH-1 to BFH-16, and the guest material of the light-emitting layer is compound 1 to compound 162 described in this invention. In the host and guest materials, the doping ratio of the guest material is 10 wt%.

[0095]

[0096]

[0097] The organic functional layer of an OLED may also include an electron transport region between the light-emitting layer and the cathode. The electron transport region can be a single-layer electron transport layer (ETL), including single-layer electron transport layers containing only one compound and single-layer electron transport layers containing multiple compounds.

[0098] In this invention, the electron transport layer material may be selected from, but is not limited to, one or more combinations of ET-1 to ET-18 listed below.

[0099]

[0100] The device may also include an electron injection layer located between the electron transport layer and the cathode layer, and the electron injection layer material includes, but is not limited to, one or more combinations of the following.

[0101] LiQ, LiF, NaCl, CsF, Li2O, Cs2CO3, BaO, Na, Li, Ca.

[0102] The present invention also discloses a display screen or display panel, wherein the display screen or display panel employs the organic electroluminescent device as described above; preferably, the display screen or display panel is an OLED display.

[0103] The present invention also discloses an electronic device having a display screen or display panel, wherein the display screen or display panel employs an organic electroluminescent device as described above.

[0104] In Device Example 1, the device structure is as follows: A glass substrate with an ITO (185nm thick) transparent conductive layer on its surface is ultrasonically treated in a commercial cleaning agent (30min / 2 times), rinsed in deionized water, then ultrasonically treated in acetone and isopropanol solvents respectively (30min / 2 times), baked in a clean environment until the solvents are completely removed, cleaned with ultraviolet light and ozone, and bombarded with a low-energy cation beam. The ITO transparent conductive layer after the above treatment is used as the anode layer. The glass plate with the anode layer is placed in the vacuum chamber of a vapor deposition equipment and evacuated to 1×10⁻⁶. -5 Pa, HT-10:HI-2 (95:5wt%) was vacuum-deposited on the anode layer as a hole injection layer and HT-10 as a hole transport layer, with film thicknesses of 10nm and 40nm, respectively; BFH-5:compound 1 (90:10wt%) was vacuum-deposited on the hole transport layer as a light-emitting layer, with a film thickness of 30nm; ET-8 was vacuum-deposited on the light-emitting layer as an electron transport layer, with a film thickness of 20nm; 1nm of LiF was vacuum-deposited on the electron transport layer as an electron injection layer and 100nm of Al was vacuum-deposited on the electron transport layer as a cathode.

[0105] The device structure of Example 1 can be briefly summarized as follows: ITO (185nm) / HT-10:HI-2 (10nm, 95:5wt%) / HT-10 (40nm) / BFH-5:compound 1 (30nm, 10%wt) / ET-8 (20nm) / LiF (1nm) / Al (100nm).

[0106] Device Examples 2-9 are the same as Device Example 1, except that the guest material compound 1 of the light-emitting layer is replaced with compound 22, compound 41, compound 57, compound 87, compound 108, compound 119, compound 141, and compound 161.

[0107] Table 2: Device Data for Device Examples

[0108]

[0109] Under the same brightness, the driving voltage and current efficiency, as well as the lifetime of the organic electroluminescent devices in Examples 1-9, were measured using a digital source meter and a luminance meter. Specifically, the voltage was increased at a rate of 0.1V per second, and the measurement was performed when the brightness of the organic electroluminescent device reached 1000 cd / m². 2 The voltage at that time is the driving voltage, and the current density at that time is measured simultaneously. The ratio of brightness to current density is the current efficiency. The life test of LT95 is shown in Table 2, using a luminance meter at 1000 cd / m². 2 At a constant current, the brightness of the organic electroluminescent device decreased to 950 cd / m² under the specified brightness. 2The time is in hours. As can be seen from the data in Table 2, due to the effective suppression of efficiency roll-off and the rapid inter-exciton antisystem crossing, the device fabricated using this patent as the guest light-emitting layer has high current efficiency and long lifetime.

Claims

1. An organic electroluminescent material containing a boron nuclear acceptor, having a general structural formula as shown in one of I, II, or III: A、A 1 They may be the same or different, and are independently selected from oxygen, sulfur, selenium, or sulfonyl groups; X is independently selected from CR 1 2. Oxygen, sulfur, selenium, carbonyl or sulfonyl groups; R, R 1 Each is independently selected from substituted or unsubstituted C1 to C1. 10 Alkyl, substituted or unsubstituted C6-C 30 Aryl, substituted or unsubstituted C3-C 30 heteroaryl; substituents selected from C1 to C2. 10 Alkyl, C6-C 30 Aryl, C3~C 30 Mixed aromatic compounds.

2. The boron-containing nuclear acceptor organic electroluminescent material as described in claim 1, characterized in that: R is independently selected from C1-C4 alkyl, substituted or unsubstituted C6-C4 alkyl groups. 30 Aryl, R 1 Independently selected from C1-C4 alkyl, substituted or unsubstituted C6-C 30 Aryl.

3. The boron-containing nuclear acceptor organic electroluminescent material as described in claim 2, characterized in that: R is independently selected from methyl, isopropyl, tert-butyl, or phenyl; R 1 It is independently selected from methyl or m-xylyl.

4. The boron-containing nuclear acceptor organic electroluminescent material as described in claim 3, characterized in that: The structural formula of the boron-containing nuclear acceptor organic electroluminescent material is shown in one of the following diagrams. Me, iPr, t-Bu, Ph, and MX represent methyl, isopropyl, tert-butyl, phenyl, and m-dimethylphenyl, respectively.

5. An organic electroluminescent device, comprising an anode layer and a cathode layer, and an organic functional layer located between the anode layer and the cathode layer; the organic functional layer includes a hole transport region, a light-emitting layer, and an electron transport region; characterized in that: The luminescent layer contains an organic electroluminescent material containing a boron nuclear acceptor as described in any one of claims 1 to 4.

6. An organic electroluminescent device as described in claim 5, characterized in that: Boron-containing nuclear acceptor organic electroluminescent materials are used as guest dopants in combination with other host materials.

7. A display screen or display panel, characterized in that: The display screen or display panel uses the organic electroluminescent device as described in claim 6.

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