Novel electroluminescent material and organic electronic device

Abstract

The invention relates to the technical field of organic photoelectric materials, and discloses a novel electroluminescent material and an organic electronic device. The electroluminescent material is a derivative of carbazole and anthracene, and is prepared through two synthetic routes: a route A takes a carbazole derivative as an initiator, and the carbazole derivative is coupled with a brominated anthracene derivative Suzuki after Ullmann coupling, lithium halogen exchange and boron esterification; a route B takes an anthracene derivative as a starting material, and the anthracene derivative is subjected to Suzuki coupling and bromination and then is subjected to secondary coupling with carbazole borate. The material has a planar conjugated structure, the carrier transport efficiency can be improved, the high triplet state energy level characteristic of the material is suitable for a blue fluorescence system, and when the material is applied to an organic electronic device as a luminescent layer main body material, the driving voltage can be remarkably reduced, the service life of the device can be prolonged, and the luminescent efficiency and the color purity can be improved.

Description

Technical Field

[0001] This invention relates to the field of organic optoelectronic materials technology, and more specifically, to a novel electroluminescent material and an organic electronic device. Background Technology

[0002] Organic light-emitting diodes (OLEDs), as self-emissive display devices, have experienced rapid development in the display field due to their significant advantages such as wide viewing angle, high contrast, and fast response speed. With the continuous growth of market demand, the structure of OLED devices has gradually evolved from the initial sandwich structure to a complex system containing multiple functional layers, including a cathode, electron injection layer, electron transport layer, organic light-emitting layer, hole transport layer, hole injection layer, anode, and substrate. Performance improvements are highly dependent on innovation in organic optoelectronic materials.

[0003] In OLED material research, blue fluorescent systems have attracted much attention due to their core role in full-color displays. However, existing blue fluorescent organic electroluminescent devices still face key bottlenecks: on the one hand, the lifespan of blue light elements is generally short, making it difficult to meet the long-term stability requirements of practical applications; on the other hand, their emission color purity is insufficient, easily leading to color shift, which limits further improvement in display performance. Among existing blue fluorescent materials, most compounds suffer from low carrier transport efficiency due to insufficient planar conjugation, or poor singlet / triplet energy level matching, due to limitations in molecular structure design, making it difficult to synergistically improve device luminous efficiency and lifespan. Simultaneously, the complex synthesis routes and high raw material costs of some materials also restrict their large-scale application. Therefore, this invention provides a novel electroluminescent material and organic electronic device to solve the aforementioned technical problems. Summary of the Invention

[0004] To address the aforementioned issues, this invention provides a novel electroluminescent material and organic electronic device. This material has a planar conjugated structure, which can improve carrier transport efficiency. Its high triplet energy level characteristics are suitable for blue fluorescent systems. When used as the main material for the luminescent layer in organic electronic devices, it can significantly reduce the driving voltage, extend the device's lifespan, and improve luminous efficiency and color purity.

[0005] To achieve the above objectives, the first objective of this invention is to provide a novel electroluminescent material, employing the following technical solution:

[0006] A novel electroluminescent material, wherein the material is a derivative of carbazole and anthracene, has the structure shown in the following formula:

[0007]

[0008] in:

[0009] R1 is selected from deuterated or non-deuterated aromatic groups with 6-18 carbon atoms;

[0010] R2 is selected from deuterated or non-deuterated aromatic groups with 6-60 carbon atoms.

[0011] Preferably, R1 is selected from the following groups:

[0012] , , , , , .

[0013] Preferably, R2 is selected from the following groups:

[0014] , , , , , , , , , .

[0015] Preferably, the structure of the novel electroluminescent material is selected from any one of the following compounds: , , , , , , , , , , , , , , , ， ， ， ， ， ， ， ， ， ， ， ， ， ， ， ， ， ， ， ， ， ， ， ， ， ， ， ， ， , , , .

[0016] This invention provides a method for preparing the novel electroluminescent material as described above, and the synthetic route is as follows:

[0017] Route A:

[0018] (a) 3-Bromocarbazole reacts with iodoaromatic hydrocarbons under reflux in a CuI / 1,10-phenanthroline catalytic system, in the presence of potassium hydroxide, and in toluene solvent to generate intermediate S1;

[0019] (b) S1 reacts with n-butyllithium in tetrahydrofuran solvent at -78°C, followed by the addition of triisopropyl borate to generate borate intermediate S2.

[0020] (c) 9-Bromoanthracene reacts with aromatic boric acid in a palladium acetate catalyzed, toluene / ethanol / water mixed solvent under reflux to generate an anthracene-aryl intermediate S3;

[0021] (d) S3 was brominated by refluxing with N-bromosuccinimide in tetrahydrofuran to give the brominated product S4.

[0022] (e) S4 and S2 undergo a secondary Suzuki coupling reaction catalyzed by palladium acetate in a toluene / ethanol / water mixed solvent to obtain the target compound;

[0023] Route B:

[0024] (a') 9-Bromoanthracene is Suzuki coupled with an aromatic boric acid in a toluene / ethanol / water mixed solvent with palladium acetate catalysis to generate an anthracene-aryl intermediate S1;

[0025] (b')S1 was brominated by refluxing with N-bromosuccinimide in tetrahydrofuran to give the brominated product S2;

[0026] (c')3-Bromocarbazole and iodoaryl hydrocarbons were refluxed in a CuI / 1,10-phenanthroline catalytic system and toluene solvent to generate carbazole-aryl intermediate S3;

[0027] (d')S3 and pinacol diboronic acid ester are boronized in a 1,4-dioxane solvent with Pd(dppf)Cl2 catalysis to generate borate ester S4.

[0028] (e')S2 and S4 were Suzuki coupled in a toluene / ethanol / water mixed solvent with palladium acetate catalysis to obtain the target compound.

[0029] In a second aspect, the present invention provides an organic electronic device comprising an anode, a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, an electron injection layer, and a cathode stacked sequentially, wherein the light-emitting layer comprises the novel electroluminescent material described above.

[0030] Preferably, the novel electroluminescent material in the light-emitting layer is used as the main material, accounting for 90-99% by mass, and the light-emitting layer also contains dopants, accounting for 1%-10% by mass, preferably 3%.

[0031] Preferably, the organic electronic device has a driving voltage ≤ 5.0V at a brightness of 1000 nits, an LT95 lifespan ≥ 93 hours, and emits blue light.

[0032] Compared with the prior art, the beneficial effects of the present invention are:

[0033] The novel electroluminescent material and organic electronic device provided by this invention have significant technical advantages. The novel electroluminescent material uses carbazole and anthracene as basic structural units. Through the rational design of R1 and R2 substituents, a good planar conjugated structure is formed. The difference between the high singlet energy level and the low triplet energy level of this derivative effectively suppresses triplet exciton quenching, enabling it to have both high exciton utilization and stable color coordinates in the blue fluorescence system, thereby improving luminous efficiency and color purity, and solving the problem of impure color in existing blue light materials. At the same time, the strong conjugation of the fused ring structure enhances the hole-electron transport balance and reduces the carrier recombination barrier in the luminescent layer. This structural characteristic effectively improves the carrier transport efficiency of the molecule and helps to reduce the accumulation and loss of charge in the device.

[0034] The preparation route of this invention constructs the molecular structure through mature reactions such as Ullmann coupling and Suzuki coupling. The synthesis steps are simple and easy to perform. The raw materials used, such as 3-bromocarbazole and 9-bromoanthracene, are common and readily available chemical raw materials, which helps to reduce production costs and achieve large-scale preparation. When this material is used as the main material of the light-emitting layer in organic electronic devices, it can be well adapted to the multilayer structure of the device. By optimizing the balance of carrier injection and transport, the driving voltage of the device is effectively reduced, while significantly extending the lifespan of the blue light element and improving the long-term stability of the device. This overcomes the key bottleneck of poor lifespan of existing blue fluorescent organic electroluminescent devices and provides strong support for the development of high-performance OLED devices. Detailed Implementation

[0035] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0036] Unless otherwise specified, the experimental methods used in the following examples are conventional methods, and the experimental materials used, unless otherwise specified, were all purchased from conventional biochemical reagent stores. All quantitative experiments in the following examples were performed in triplicate, and the data are the average of the three replicates or the average ± standard deviation.

[0037] Example 1

[0038] This embodiment provides a method for preparing an electroluminescent material compound 13 having the following structural formula, which includes the following steps:

[0039]

[0040] (1) Synthesis of intermediate S1:

[0041] Under nitrogen protection, 100 mmol of 3-bromocarbazole, 120 mmol of iodobenzene, 200 mmol of potassium hydroxide, 1.0 mmol of 1,10-phenanthroline, and 1.0 mmol of CuI were added to a reaction flask. 300 mL of toluene was used as the reaction solvent. After nitrogen purging, the mixture was refluxed and the pH was adjusted to neutral with dilute hydrochloric acid. The mixture was extracted, washed with water, and dried. The crude product was purified by toluene column chromatography, concentrated under reduced pressure until a large amount of solid precipitated, filtered, recrystallized from toluene, and dried to obtain 24.2 g of a light yellow solid S1, with a yield of 75%.

[0042] (2) Synthesis of intermediate S2:

[0043] 75 mmol of S1 was dissolved in 360 ml of tetrahydrofuran. Under nitrogen protection, the temperature was lowered to -78 °C, and 40 ml of 2.5 M n-butyllithium solution was added dropwise. After the addition was complete, the reaction was maintained at this temperature for 1 hour. Then, 115 mmol of triisopropyl borate was added dropwise at -78 °C, and the reaction was maintained for another hour. The temperature was then naturally raised to room temperature and stirred overnight. The reaction solution was quenched with dilute hydrochloric acid, and tetrahydrofuran was removed by vacuum distillation. 120 ml of petroleum ether was added to the residue and stirred for 0.5 hours. The mixture was filtered, and the filter cake was washed with water until neutral. After drying, 19.4 g of off-white solid S2 was obtained, with a yield of 90%.

[0044] (3) Synthesis of intermediate S3:

[0045] In a nitrogen atmosphere, 60 mmol of 9-bromoanthracene, 65 mmol of S2, 120 mmol of potassium carbonate, and 0.3 mmol of palladium acetate were added to a reaction flask. A mixed solvent of 95 ml toluene, 15 ml ethanol, and 45 ml water was used. After nitrogen purging, the mixture was refluxed for 2 hours until TLC monitoring showed complete conversion of 9-bromoanthracene. The reaction solution was cooled to room temperature, water was added, and the mixture was filtered. The filter cake was washed with water, slurried with ethanol, filtered, and dried. The crude product was dissolved in toluene, purified by column chromatography, and the eluent was concentrated and crystallized. After filtration and drying, 22.9 g of the yellow-green compound S3 was obtained, with a yield of 91%.

[0046] (4) Synthesis of intermediate S4

[0047] 50 mmol of S3 was dissolved in 210 mL of tetrahydrofuran. Under nitrogen protection, 55 mmol of N-bromosuccinimide was added, and the mixture was refluxed for 3 hours until S3 was completely converted as monitored by TLC. After cooling, the reaction solution was quenched with sodium bisulfite aqueous solution, and the organic phase was removed by concentration under reduced pressure. 100 mL of ethanol was added to the residue, and the mixture was refluxed and stirred. After cooling to room temperature, the mixture was filtered. The filter cake was washed with water and stirred again with ethanol. After filtration and drying, 24.9 g of yellow-green compound S4 was obtained, with a yield of 100%.

[0048] (5) Synthesis of target compound 13

[0049] Under nitrogen protection, 50 mmol of S4, 50 mmol of benzo[B]naphtho[2,3-D]furan-2-boric acid, 100 mmol of potassium carbonate, and 0.5 mmol of palladium acetate were added to a reaction flask. A mixed solvent of 150 ml toluene, 25 ml ethanol, and 75 ml water was used. After nitrogen purging, the mixture was refluxed for 8 hours. TLC monitoring showed complete conversion of S4. The reaction solution was cooled to room temperature, water was added, and the mixture was filtered. The filter cake was washed with water and slurried with ethanol. After filtration and drying, the crude product was dissolved in toluene and purified by column chromatography. The eluent was concentrated and recrystallized multiple times from toluene. After drying, 15.5 g of yellow-green compound 13 was obtained, with a yield of 49%.

[0050] Structural characterization:

[0051] Compound 13 was analyzed by LCMS; its molecular formula is C13. 48 H 29 NO, with a standard molecular weight of 635.75 and a measured mass-to-charge ratio of 635.35 [M+].

[0052] The reaction process is as follows:

[0053]

[0054] Example 2

[0055] This embodiment provides a method for preparing an electroluminescent material compound 29 having the following structural formula, which includes the following steps:

[0056]

[0057] (1) Synthesis of intermediate S1:

[0058] Under nitrogen protection, 100 mmol of 9-bromoanthracene, 110 mmol of 2-phenanthroline ester, 200 mmol of potassium carbonate, and 2 mmol of palladium acetate were added to a reaction flask. A mixed solvent of 150 ml toluene, 25 ml ethanol, and 75 ml water was used. After nitrogen purging, the mixture was heated to reflux for 8 hours until 9-bromoanthracene was completely converted. The mixture was then cooled to room temperature and filtered. The filter cake was washed with water until neutral, dried by forced air, and the crude product was dissolved in toluene and passed through a silica gel column. The solution was concentrated, filtered to crystallize, and the solid was recrystallized from toluene and dried to give 25.2 g of a yellow-green solid S1, with a yield of 71%.

[0059] (2) Synthesis of intermediate S2:

[0060] 70 mmol of S1 and 75 mmol of N-bromosuccinimide were added to a reaction flask. The mixture was refluxed for 2 hours in 250 ml of tetrahydrofuran as solvent until S1 was completely converted. After cooling to room temperature, the reaction was quenched with sodium bisulfite aqueous solution. The mixture was concentrated, crystallized, and filtered. The resulting solid was slurried with ethanol and dried to obtain 30.3 g of yellow solid S2, with a yield of 100%.

[0061] (3) Synthesis of intermediate S3:

[0062] In a nitrogen atmosphere, 100 mmol of 3-bromocarbazole, 120 mmol of 2-iodonaphthalene, 200 mmol of potassium hydroxide, 1.0 mmol of 1,10-phenanthroline, and 1.0 mmol of CuI were added to a reaction flask. 300 mL of toluene was used as the solvent. After nitrogen purging, the mixture was refluxed overnight. After the reaction was complete, the temperature was lowered, and the pH was adjusted to neutral with dilute hydrochloric acid. The product was extracted, washed with water, and dried. The crude product was purified by toluene column chromatography, concentrated under reduced pressure until a large amount of solid precipitated, filtered, recrystallized from toluene, and dried to obtain 29 g of a light yellow solid S3, with a yield of 78%.

[0063] (4) Synthesis of intermediate S4:

[0064] 50 mmol of S3, 60 mmol of pinacol diborate, 100 mmol of potassium acetate, and 0.25 mmol of Pd(dppf)Cl2 were added to a reaction flask. 200 mL of 1,4-dioxane was used as the solvent. After nitrogen purging, the mixture was refluxed for 4 hours until S3 was completely converted. The reactants were cooled to room temperature, concentrated to remove the solvent, and 100 mL of water was added. The residue was dissolved in 200 mL of DCM. After separation, the organic phase was washed with water until neutral, dried with a small amount of anhydrous sodium sulfate, passed through a column, washed with DCM, concentrated, and then dispersed and crystallized in 100 mL of petroleum ether. After filtration and drying, 18.0 g of grayish-white solid S4 was obtained, with a yield of 86%.

[0065] (5) Synthesis of target compound 29:

[0066] Under nitrogen protection, 40 mmol of S2, 40 mmol of S4, 80 mmol of potassium carbonate and 0.2 mmol of palladium acetate were added to the reaction flask. A mixed solvent of 120 ml toluene, 20 ml ethanol and 60 ml water was used. After nitrogen purging, the mixture was refluxed overnight until S2 was completely converted. The reactants were cooled to room temperature, water was added and the mixture was filtered. The filter cake was washed with water and slurried with ethanol. After filtration and drying, the crude product was dissolved in toluene and purified by column chromatography. The concentrate was passed through the column and recrystallized multiple times from toluene. After drying, 9.6 g of yellow-green compound 29 was obtained, with a yield of 37%.

[0067] Structural characterization:

[0068] Compound 29, with the molecular formula C, was analyzed by LCMS. 50 H 31 N, with a standard molecular weight of 645.79 and a measured mass-to-charge ratio of 645.31 [M+].

[0069] The reaction process is as follows:

[0070]

[0071] Example 3

[0072] This embodiment provides a method for preparing an electroluminescent material compound 33 having the following structural formula, which includes the following steps:

[0073]

[0074] (1) Synthesis of intermediate S1:

[0075] Under nitrogen protection, 100 mmol of 9-bromoanthracene, 110 mmol of dibenzofuran-2-boric acid, 200 mmol of potassium carbonate, and 2 mmol of palladium acetate were added to a reaction flask. A mixed solvent of 150 ml toluene, 25 ml ethanol, and 75 ml water was used. After nitrogen purging, the mixture was heated to reflux for 4 hours until TLC monitoring showed complete conversion of 9-bromoanthracene. The mixture was then cooled to room temperature, filtered, and the filter cake was washed with water until neutral. It was then dried by forced air drying, dissolved in toluene, and passed through a silica gel column. The concentrate was then filtered, crystallized, and the solid was recrystallized from toluene and dried to obtain 27.9 g of yellow-green solid S1, with a yield of 81%.

[0076] (2) Synthesis of intermediate S2:

[0077] 80 mmol of S1 and 85 mmol of N-bromosuccinimide were added to a reaction flask, and the mixture was refluxed for 2 hours in 270 mL of tetrahydrofuran as solvent until S1 was completely converted as monitored by TLC. The mixture was cooled to room temperature, quenched with sodium bisulfite aqueous solution, concentrated, crystallized, and filtered. The resulting solid was then slurried with ethanol and dried to give 32.2 g of yellow solid S2, with a yield of 95%.

[0078] (3) Synthesis of intermediate S3:

[0079] Under nitrogen protection, 100 mmol of 3-bromocarbazole, 120 mmol of 2-iodonaphthalene, 200 mmol of potassium hydroxide, 1.0 mmol of 1,10-phenanthroline, and 1.0 mmol of CuI were added to a reaction flask. 300 mL of toluene was used as the reaction solvent. After nitrogen purging, the mixture was refluxed overnight. After the reaction was complete, the temperature was lowered, and the pH was adjusted to neutral with dilute hydrochloric acid. The product was extracted, washed with water, and dried. The crude product was purified by toluene column chromatography, concentrated under reduced pressure until a large amount of solid precipitated, filtered, recrystallized from toluene, and dried to obtain 29 g of a light yellow solid S3, with a yield of 78%.

[0080] (4) Synthesis of intermediate S4:

[0081] In a nitrogen atmosphere, 50 mmol of S3, 60 mmol of pinacol diborate, 100 mmol of potassium acetate, and 0.25 mmol of Pd(dppf)Cl2 were added to a reaction flask. Using 200 mL of 1,4-dioxane as solvent, the mixture was refluxed for 3 hours after nitrogen purging until TLC monitoring showed complete conversion of S3. After cooling the reactants to room temperature, the solvent was removed by concentration. 100 mL of water and 200 mL of DCM were added to dissolve the residue. The organic phase was separated, washed with water until neutral, dried over anhydrous sodium sulfate, and passed through a column. After washing with DCM, the mixture was concentrated and dispersed in 100 mL of petroleum ether to crystallize. The crystals were filtered and dried to obtain 18.0 g of grayish-white solid S4, with a yield of 86%.

[0082] (5) Synthesis of target compound 33:

[0083] Under nitrogen protection, 40 mmol of S2, 40 mmol of S4, 80 mmol of potassium carbonate and 0.2 mmol of palladium acetate were added to the reaction flask. A mixed solvent of 120 ml toluene, 20 ml ethanol and 60 ml water was used. After nitrogen purging, the mixture was refluxed overnight until TLC monitoring showed no S2 remaining. The reactants were cooled to room temperature, water was added, filtered, washed with water, and the resulting solid was slurried with ethanol, filtered and dried. The solid was dissolved in toluene and passed through a column. The column solution was concentrated, recrystallized from toluene multiple times, and dried to obtain 15.7 g of yellow-green compound 33, with a yield of 62%.

[0084] Structural characterization:

[0085] Compound 33 was analyzed by LCMS; its molecular formula is C3. 48 H 29 NO, with a standard molecular weight of 635.75 and a measured mass-to-charge ratio of 635.35 [M+].

[0086] The reaction process is as follows:

[0087]

[0088] Example 4

[0089] This embodiment provides a method for preparing an electroluminescent material compound 41 having the following structural formula, which includes the following steps:

[0090]

[0091] (1) Synthesis of intermediate S1:

[0092] Under nitrogen protection, 100 mmol of 9-bromoanthracene, 105 mmol of benzo[B]naphtho[2,3-D]furan-2-boric acid, 200 mmol of potassium carbonate, and 2 mmol of palladium acetate were added to a reaction flask. A mixed solvent of 150 ml toluene, 25 ml ethanol, and 75 ml water was used. After nitrogen purging, the mixture was heated to reflux for 6 hours until the 9-bromoanthracene starting material was completely converted. The mixture was then cooled to room temperature, filtered, and the filter cake was washed with water until neutral. It was then dried by forced air drying, dissolved in toluene, and passed through a silica gel column. The concentrate was filtered, crystallized, and the solid was recrystallized from toluene and dried to obtain 32.7 g of yellow-green solid S1, with a yield of 83%.

[0093] (2) Synthesis of intermediate S2:

[0094] 80 mmol of S1 and 85 mmol of N-bromosuccinimide were added to a reaction flask. The mixture was refluxed for 2 hours in 315 ml of tetrahydrofuran as solvent until S1 was completely converted. The mixture was cooled to room temperature, quenched with sodium bisulfite aqueous solution, concentrated, crystallized, and filtered. The resulting solid was slurried with ethanol and dried to obtain 36 g of yellow solid S2, with a yield of 95%.

[0095] (3) Synthesis of intermediate S3:

[0096] In a nitrogen atmosphere, 100 mmol of 3-bromocarbazole, 120 mmol of 2-iodonaphthalene, 200 mmol of potassium hydroxide, 1.0 mmol of 1,10-phenanthroline, and 1.0 mmol of CuI were added to a reaction flask. 300 mL of toluene was used as the reaction solvent. After nitrogen purging, the mixture was refluxed overnight. After the reaction was complete, the temperature was lowered, and the pH was adjusted to neutral with dilute hydrochloric acid. The product was extracted, washed with water, and dried. The crude product was purified by toluene column chromatography, concentrated under reduced pressure until a large amount of solid precipitated, filtered, recrystallized from toluene, and dried to obtain 29 g of a light yellow solid S3, with a yield of 78%.

[0097] (4) Synthesis of intermediate S4:

[0098] 50 mmol of S3, 60 mmol of pinacol diborate, 100 mmol of potassium acetate, and 0.25 mmol of Pd(dppf)Cl2 were added to a reaction flask. 200 mL of 1,4-dioxane was used as the solvent. After nitrogen purging, the mixture was refluxed for 3 hours until S3 was completely converted. The reactants were cooled to room temperature, concentrated to remove the solvent, and 100 mL of water and 200 mL of DCM were added to dissolve the residue. The organic phase was separated and washed with water until neutral. A small amount of anhydrous sodium sulfate was added for drying. The mixture was then passed through a column, washed with DCM, concentrated, and dispersed in 100 mL of petroleum ether to crystallize. After filtration and drying, 18.0 g of grayish-white solid S4 was obtained, with a yield of 86%.

[0099] (5) Synthesis of target compound 41:

[0100] Under nitrogen protection, 40 mmol of S2, 40 mmol of S4, 80 mmol of potassium carbonate and 0.2 mmol of palladium acetate were added to the reaction flask. A mixed solvent of 130 ml toluene, 20 ml ethanol and 60 ml water was used. After nitrogen purging, the mixture was refluxed overnight until almost no S2 remained. The reactants were cooled to room temperature, water was added, filtered, washed with water, and the resulting solid was slurried with ethanol, filtered and dried. The solid was dissolved in toluene and passed through a column. The column solution was concentrated, recrystallized from toluene multiple times, and dried to obtain 10.7 g of yellow-green compound 41, with a yield of 39%.

[0101] Structural characterization:

[0102] Compound 41, with the molecular formula C, was analyzed by LCMS.52 H 31 NO, the standard molecular weight is 685.81, and the measured mass-to-charge ratio is 685.39 [M+].

[0103] The reaction process is as follows:

[0104]

[0105] Example 5

[0106] This embodiment provides a method for preparing an electroluminescent material compound 55 having the following structural formula, which includes the following steps:

[0107]

[0108] (1) Synthesis of intermediate S1:

[0109] Under nitrogen protection, 150 mmol of 3-bromocarbazole, 180 mmol of 2-iodonaphthalene, 300 mmol of potassium hydroxide, 1.5 mmol of 1,10-phenanthroline, and 1.5 mmol of CuI were added to a reaction flask. 450 ml of toluene was used as the reaction solvent. After nitrogen purging, the mixture was refluxed overnight. After the reaction was completed, the temperature was lowered, and the pH was adjusted to neutral with dilute hydrochloric acid. The product was extracted, washed with water, and dried. The crude product was purified by toluene column chromatography, concentrated under reduced pressure until a large amount of solid precipitated, filtered, recrystallized from toluene, and dried to obtain 43.5 g of yellowish-brown solid S1, with a yield of 78%.

[0110] (2) Synthesis of intermediate S2:

[0111] In a nitrogen atmosphere, 100 mmol of S1, 120 mmol of pinacol diborate, 200 mmol of potassium acetate, and 0.5 mmol of Pd(dppf)Cl2 were added to a reaction flask. 400 mL of 1,4-dioxane was used as the solvent. After nitrogen purging, the mixture was refluxed for 3 hours until S1 was completely converted. After cooling to room temperature, the solvent was removed by concentration. The residue was dissolved in 200 mL of water and 400 mL of DCM. After separation, the organic phase was washed with water until neutral, dried over anhydrous sodium sulfate, filtered, concentrated, and then dispersed and crystallized in 200 mL of petroleum ether. After filtration and drying, 36.0 g of grayish-white solid S2 was obtained, with a yield of 86%.

[0112] (3) Synthesis of intermediate S3:

[0113] Under nitrogen protection, 50 mmol of 9-bromoanthracene, 50 mmol of S2, 100 mmol of potassium carbonate, and 0.5 mmol of Pd(PPh3)4 were added to a reaction flask. A mixed solvent of 90 ml toluene, 25 ml ethanol, and 40 ml water was used. The mixture was refluxed for 8 hours, cooled to room temperature, filtered, and the filter cake was dried. The solution was then dissolved under reflux in 500 ml of toluene. Mechanical impurities were removed by passing the solution through a thin silica gel column, and the solution was concentrated to approximately 100 ml. Crystallization was carried out at a cooling temperature for 1 hour. After filtration, the filter cake was recrystallized from toluene and dried to obtain 19.3 g of yellow-green solid S3, with a yield of 82%.

[0114] (4) Synthesis of intermediate S4

[0115] 40 mmol of S3 was dissolved in 200 mL of tetrahydrofuran. Under nitrogen protection, 85 mmol of N-bromosuccinimide was added, and the mixture was refluxed for 2 hours until S3 was completely converted. After cooling to room temperature, the reaction was quenched with an aqueous sodium bisulfite solution. The solution was concentrated, crystallized, filtered, and the resulting solid was slurried with ethanol and dried to give 21.9 g of yellow solid S4, with a yield of 100%.

[0116] (5) Synthesis of target compound 55

[0117] Under nitrogen protection, 40 mmol of S4, 40 mmol of S2, 80 mmol of potassium carbonate, and 0.2 mmol of palladium acetate were added to a reaction flask. Using a mixed solvent of 150 ml toluene, 20 ml ethanol, and 60 ml water, the mixture was refluxed overnight. After cooling to room temperature, 100 ml of water was added, and the mixture was filtered. The filter cake was washed with water, slurried with ethanol, filtered again, and dried. The crude product was dissolved in toluene, purified by column chromatography, and the eluent was concentrated. It was then recrystallized multiple times from toluene and dried to give 9.7 g of the yellow-green compound 55, with a yield of 32%.

[0118] Structural characterization

[0119] Compound 55, with the molecular formula C, was analyzed by LCMS. 58 H 36 N2 has a standard molecular weight of 760.92 and a measured mass-to-charge ratio of 760.28 [M+].

[0120] The reaction process is as follows:

[0121]

[0122] Example 6

[0123] This embodiment provides a method for preparing an electroluminescent material compound 69 having the following structural formula, which includes the following steps:

[0124]

[0125] (1) Synthesis of intermediate S1:

[0126] Under nitrogen protection, 100 mmol of 9-bromoanthracene, 105 mmol of benzo[B]naphtho[2,3-D]furan-2-boric acid, 200 mmol of potassium carbonate and 2 mmol of palladium acetate were added to a reaction flask. A mixed solvent of 150 ml toluene, 25 ml ethanol and 75 ml water was used. After nitrogen purging, the mixture was heated to reflux for 6 hours until 9-bromoanthracene was completely converted. The mixture was cooled to room temperature and filtered. The filter cake was washed with water until neutral, dried by forced air, dissolved in toluene, and passed through a silica gel column. The concentrate was filtered, crystallized, and the solid was recrystallized from toluene and dried to obtain 32.7 g of yellow-green solid S1, with a yield of 83%.

[0127] (2) Synthesis of intermediate S2:

[0128] 80 mmol of S1 was dissolved in 315 ml of tetrahydrofuran. Under nitrogen protection, 85 mmol of N-bromosuccinimide was added, and the mixture was refluxed for 2 hours until S1 was completely converted. After cooling to room temperature, the reaction was quenched with sodium bisulfite aqueous solution. After concentration, crystallization was performed, and the obtained solid was filtered, slurried with ethanol, and dried to give 36 g of yellow solid S2, with a yield of 95%.

[0129] (3) Synthesis of intermediate S3:

[0130] Under nitrogen protection, 100 mmol of 3-bromocarbazole, 120 mmol of 1-iodonaphthalene, 200 mmol of potassium hydroxide, 1.0 mmol of 1,10-phenanthroline, and 1.0 mmol of CuI were added to a reaction flask. 300 mL of toluene was used as the reaction solvent. After nitrogen purging, the mixture was refluxed overnight. After the reaction was complete, the temperature was lowered, and the pH was adjusted to neutral with dilute hydrochloric acid. The product was extracted, washed with water, and dried. The crude product was purified by toluene column chromatography, concentrated under reduced pressure until a large amount of solid precipitated, filtered, recrystallized from toluene, and dried to obtain 28.2 g of a light yellow solid S3, with a yield of 76%.

[0131] (4) Synthesis of intermediate S4:

[0132] In a nitrogen atmosphere, 50 mmol of S3, 60 mmol of pinacol diborate, 100 mmol of potassium acetate, and 0.25 mmol of Pd(dppf)Cl2 were added to a reaction flask. 200 ml of 1,4-dioxane was used as the solvent. After nitrogen purging, the mixture was refluxed for 3 hours until S3 was completely converted. After cooling to room temperature, the solvent was removed by concentration. The residue was dissolved in 100 ml of water and 200 ml of DCM. After separation, the organic phase was washed with water until neutral, dried over anhydrous sodium sulfate, filtered, concentrated, and then dispersed and crystallized in 100 ml of petroleum ether. After filtration and drying, 17.4 g of grayish-white solid S4 was obtained, with a yield of 83%.

[0133] (5) Synthesis of target compound 69:

[0134] Under nitrogen protection, 40 mmol of S2, 40 mmol of S4, 80 mmol of potassium carbonate and 0.2 mmol of palladium acetate were added to the reaction flask. A mixed solvent of 130 ml toluene, 20 ml ethanol and 60 ml water was used. After nitrogen purging, the mixture was refluxed overnight until no S2 remained. After cooling to room temperature, water was added, and the mixture was filtered. The filter cake was washed with water, slurried with ethanol, filtered and dried. The crude product was dissolved in toluene and purified by column chromatography. The eluent was concentrated and recrystallized multiple times from toluene. After drying, 11.2 g of yellow-green compound 69 was obtained, with a yield of 41%.

[0135] Structural characterization

[0136] Compound 69 was analyzed by LCMS; its molecular formula is C69. 52 H 31 NO, with a standard molecular weight of 685.81 and a measured mass-to-charge ratio of 685.37 [M+].

[0137] The reaction process is as follows:

[0138]

[0139] Comparative Example 1

[0140] This comparative example proposes a luminescent material with the following structural formula:

[0141]

[0142] Comparative Example 2

[0143] This comparative example proposes a luminescent material with the following structural formula:

[0144]

[0145] Test case:

[0146] An OLED device was fabricated using the light-emitting materials obtained in Examples 1-6 and Comparative Examples 1-2. The OLED device includes a first hole injection layer (HIL-1), a second hole injection layer (HIL-2), a first hole transport layer (HTL-1), a second hole transport layer (HTL-2), an organic light-emitting layer, an electron transport layer (ETL), an electron transport layer, an electron injection layer (EIL), and a cathode (Cthd) sequentially deposited on an ITO substrate.

[0147] The ITO substrate fabrication process is as follows: a glass substrate coated with an ITO transparent conductive layer (as the anode) is ultrasonically treated in a cleaning agent, then rinsed in deionized water, ultrasonically degreased in a mixed solvent of acetone and ethanol, baked in a clean environment until completely dehydrated, cleaned with ultraviolet light and ozone, and bombarded with a low-energy cation beam to improve surface properties and enhance the bonding ability with the hole transport layer. Subsequently, the vacuum level of the vacuum evaporation machine is maintained at 1x10⁻⁶ torr to 3x10⁻⁷ torr, and various organic and metallic materials are sequentially deposited on the ITO substrate to obtain the OLED devices of the embodiments and comparative examples.

[0148] In each layer of the OLED device described above, HAT is used to form HI-1 and HID; HI-2 is used to form HI-2; HT-1 and HT-2 are used to form HTL-1 and HTL-2; Liq is used to form ETD and EIL; ET is the main material for forming ETL; the novel compound of the embodiment and the compound of the comparative example are used to form BEL; BD can be used as a dopant for BEL. The detailed structural formulas of the above compounds are listed in Table 1 below.

[0149] Table 1:

[0150]

[0151] The main difference between the OLED device of the embodiment and the OLED device of the comparative example is that the BEL in the OLED device of the comparative example is made of the novel compound described in the previous table, as shown in Table 2 below.

[0152] Table 2

[0153]

[0154] Table 3 below shows the materials, thicknesses, doping ratios, and coating sequences of each organic layer in an OLED device.

[0155] Table 3

[0156]

[0157] Evaluation of OLED devices: To evaluate the performance of OLED devices, the OLED devices were connected to a power supply (brand: Keithley; model: 2400) and tested with a PR650 luminance meter. The OLED devices were tested at a brightness of 1000 nits. The test results are shown in Table 4.

[0158] Table 4

[0159]

[0160] Performance testing of the OLED devices prepared in Examples 1-6 and Comparative Examples 1-2 showed that the devices in the Examples were significantly better than those in the Comparative Examples in terms of key performance indicators. At a brightness of 1000 nits, the driving voltage of the devices in the Examples was ≤5.0V, the LT95 lifetime was ≥93 hours, and the emission color purity was high, exhibiting stable blue emission. In contrast, the driving voltage of the devices in the Comparative Examples was significantly higher, the lifetime was greatly shortened, and there were also differences in luminous efficiency and color purity.

[0161] This difference stems from the fundamental difference in material structure design. The novel electroluminescent material in this embodiment of the invention uses carbazole and anthracene as core structural units. By rationally introducing R1 and R2 substituents, a planar conjugated system is formed, which effectively improves the carrier transport efficiency and reduces charge accumulation loss. At the same time, the high triplet energy level characteristics suppress triplet exciton quenching, ensuring high exciton utilization and stable color coordinates. In contrast, the comparative material lacks efficient conjugated structure and energy level matching design. The imbalance in carrier transport leads to an increase in recombination barrier and severe exciton loss, which in turn causes the device driving voltage to increase, the lifetime to shorten, and the luminescence performance to decrease.

[0162] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. A novel electroluminescent material, characterized in that, The material is a derivative of carbazole and anthracene, and has the structure shown in the following formula: in: R1 is selected from deuterated or non-deuterated aromatic groups with 6-18 carbon atoms; R2 is selected from deuterated or non-deuterated aromatic groups with 6-60 carbon atoms.

2. The novel electroluminescent material according to claim 1, characterized in that, R1 is selected from the following groups: ， ， ， ， ， 。 3. The novel electroluminescent material according to claim 1, characterized in that, The R2 is selected from the following groups: , , , , , , ， ， ， 。 4. The novel electroluminescent material according to claim 1, characterized in that, The structure of the novel electroluminescent material is selected from any one of the following compounds: ， ， ， ， ， ， ， ， ， ， ， ， ， ， ， ， ， ， ， ， ， ， ， ， ， ， ， ， ， ， ， ， ， ， ， ， ， ， ， ， ， ， ， ， ， ， ， 。 5. A method for preparing a novel electroluminescent material as described in any one of claims 1-4, characterized in that, Its synthetic route is as follows: Route A: (a) 3-Bromocarbazole reacts with iodoaromatic hydrocarbons under reflux in a CuI / 1,10-phenanthroline catalytic system, in the presence of potassium hydroxide, and in toluene solvent to generate intermediate S1; (b) S1 reacts with n-butyllithium in tetrahydrofuran solvent at -78°C, followed by the addition of triisopropyl borate to generate borate intermediate S2. (c) 9-Bromoanthracene reacts with aromatic boric acid in a palladium acetate catalyzed, toluene / ethanol / water mixed solvent under reflux to generate an anthracene-aryl intermediate S3; (d) S3 was brominated by refluxing with N-bromosuccinimide in tetrahydrofuran to give the brominated product S4. (e) S4 and S2 undergo a secondary Suzuki coupling reaction catalyzed by palladium acetate in a toluene / ethanol / water mixed solvent to obtain the target compound; Route B: (a') 9-Bromoanthracene is Suzuki coupled with an aromatic boric acid in a toluene / ethanol / water mixed solvent with palladium acetate catalysis to generate an anthracene-aryl intermediate S1; (b')S1 was brominated by refluxing with N-bromosuccinimide in tetrahydrofuran to give the brominated product S2; (c')3-Bromocarbazole and iodoaryl hydrocarbons were refluxed in a CuI / 1,10-phenanthroline catalytic system and toluene solvent to generate carbazole-aryl intermediate S3; (d')S3 and pinacol diboronic acid ester are boronized in a 1,4-dioxane solvent with Pd(dppf)Cl2 catalysis to generate borate ester S4. (e')S2 and S4 were Suzuki coupled in a toluene / ethanol / water mixed solvent with palladium acetate catalysis to obtain the target compound.

6. An organic electronic device, characterized in that, It comprises an anode, a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, an electron injection layer, and a cathode, which are stacked in sequence, wherein the light-emitting layer comprises the novel electroluminescent material according to any one of claims 1-4.

7. The organic electronic device according to claim 6, characterized in that, The novel electroluminescent material is the main material in the light-emitting layer, accounting for 90-99% of its mass. The light-emitting layer also contains dopants, which account for 1%-10% of the mass, preferably 3%.

8. The organic electronic device according to claim 7, characterized in that, The organic electronic device has a driving voltage ≤5.0V at a brightness of 1000 nits, an LT95 lifespan ≥93 hours, and emits blue light.

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