Electroluminescent compound and electroluminescent device thereof

Abstract

The application belongs to the technical field of organic light-emitting materials and semiconductors, and provides an electroluminescent compound and an electroluminescent device thereof. The structure of the electroluminescent compound is shown in formula 1: the compound takes a fluorinated conjugated skeleton as a main structure, a fluorine atom is introduced into a central benzene ring, heteroaryl groups are bonded on both sides, and peripheral large steric substituents and fused ring aryl groups are cooperatively modified, multi-dimensional performance optimization is realized for the core performance requirements of an electron transport type host light-emitting material, and the problems of carrier transport imbalance, poor energy level matching, weak exciton confinement ability and insufficient morphological stability of the existing host light-emitting material can be solved.

Description

Technical Field

[0001] This invention belongs to the field of organic light-emitting materials and semiconductor technology, specifically relating to an electroluminescent compound and its electroluminescent device. Background Technology

[0002] Organic light-emitting diodes (OLEDs) have become a core technology choice in high-end displays and solid-state lighting due to their self-emissive, high color gamut, and flexible stretchability. The emitting layer, as the core functional area of ​​an OLED device, typically employs a host-guest doping system. The host emitting material not only undertakes the responsibility of regulating carrier transport and recombination dynamics but also needs to restrict exciton diffusion and suppress energy back-transfer. Its energy level structure, carrier mobility, and thermal stability directly determine the device's luminous efficiency, driving voltage, and operating lifetime.

[0003] Existing host light-emitting materials still face significant technical bottlenecks, severely restricting the engineering application of high-performance OLED devices. On the one hand, traditional electron transport-type host light-emitting materials generally suffer from low electron mobility, leading to an imbalance in electron-hole transport within the light-emitting layer, uneven distribution of exciton recombination regions, and consequently, nonradiative recombination losses and efficiency roll-off. Simultaneously, some materials suffer from excessive extension of the conjugated system, resulting in triplet energy levels (…). E T The glass transition temperature (T0) of some materials is too low, making it difficult to meet the exciton confinement requirements of blue light and high-energy devices. Furthermore, the matching degree between the frontier molecular orbital (HOMO / LUMO) energy levels and the hole blocking layer and guest light-emitting material is poor, easily leading to carrier traps and accelerating device aging. On the other hand, the glass transition temperature (T0) of some materials is also low. g The low thermal stability and thin film morphology stability make the device prone to crystallization during operation, which can lead to aggregation-induced quenching and further degrade device performance and lifespan.

[0004] To address the aforementioned pain points, developing novel host light-emitting materials that combine high electron mobility, excellent energy level matching, good thermal stability, and exciton confinement capability has become a key technological requirement for breaking through the performance bottleneck of OLED devices and promoting their commercial application. Summary of the Invention

[0005] The purpose of this invention is to provide an electroluminescent compound and its electroluminescent device to solve the problems of carrier transport imbalance, poor energy level matching, weak exciton confinement ability and insufficient morphological stability in existing host light-emitting materials.

[0006] This invention is achieved through the following technical solution: In a first aspect, the present invention discloses an electroluminescent compound having the structure shown in Formula 1:

[0007] In the formula: R1 and R2 are independently selected from substituted or unsubstituted C6~C6 cells, respectively. 20 aryl groups; wherein R1 and R2 may be the same or different; Ar1 and Ar2 are independently selected from the substituted C3~C. 20 heteroaryl groups; the C3~C 20 The substituents of the heteroaryl group are selected from substituted or unsubstituted phenyl groups, substituted or unsubstituted naphthyl groups, and C1-C2 groups. 10 Alkyl groups; heteroaryl groups contain at least one nitrogen atom in their heteroatom.

[0008] Preferably, the substituted or unsubstituted C6~C in R1 and R2 20 The aryl group refers to the C6~C 20 The aryl group can be further substituted by substituents, or it can remain unsubstituted, when C6~C6. 20 When the aryl group is replaced by a substituent, the substituent is selected from C1 to C2. 10 Alkyl, C1~C 10 alkoxy groups.

[0009] Preferably, when the phenyl and naphthyl groups are substituted with substituents, the substituents are selected from C1 to C2. 10 Alkyl groups.

[0010] Preferably, C3~C 20 The heteroaryl group is selected from triazine, pyrimidine, .

[0011] Preferably, R1 and R2 in Formula 1 are each independently selected from the following groups A1 to A18:

[0012] Among the groups A1~A18, " "Indicates R1, R2 and the main structure The bonding positions.

[0013] Preferably, the electroluminescent compound is one of the following compounds 1 to 120: .

[0014] A second aspect of the present invention provides an electroluminescent device, the electroluminescent device comprising a cathode layer, an anode layer, and an organic layer located between the cathode layer and the anode layer; the organic layer, from the anode layer to the cathode layer, sequentially comprises a hole injection layer (HIL), a hole transport layer, an electron blocking layer (EBL), an emission material layer (EML), a hole blocking layer (HBL), an electron transport layer, and an electron injection layer (EIL); the emission material layer comprises a host emission material and a guest emission material, the host emission material comprising a hole transport host material and an electron transport host material, the electron transport host material comprising the electroluminescent compound shown in Formula 1 above.

[0015] The hole transport host material is selected from any one of the following compounds: .

[0016] Preferably, in embodiments of the present invention, the main luminescent material is a conventional material with excellent performance. The electroluminescent compound described in this invention is obtained by composite co-evaporation at a mass ratio of 1:1.

[0017] The guest luminescent material is selected from one of the following compounds: .

[0018] Preferably, the mass of the guest luminescent material accounts for 1.0% to 5.0% of the mass of the luminescent layer.

[0019] In a specific embodiment of the present invention, the electroluminescent device comprises, in sequence from the anode layer to the cathode layer, a substrate, an anode layer, a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, a hole blocking layer, an electron transport layer, an electron injection layer, and a cathode layer.

[0020] As a substrate, it needs to have high mechanical strength, excellent thermal stability, excellent water resistance and excellent transparency; polyethylene terephthalate (PET) plastic is preferred.

[0021] As the anode layer, the anode layer material is preferably a material with a high work function in order to facilitate the injection of holes into the organic layer. Specific examples of anode layer materials that can be used in this invention include: metals such as vanadium, chromium, copper, zinc, and gold, or their alloys; oxides such as zinc oxide, tin oxide, or indium tin oxide; and conductive polymers such as polypyrrole and polyaniline.

[0022] Preferably, the hole injection layer material in this invention is MoO3.

[0023] Preferably, the hole transport layer material in this invention is selected from one of the following materials: .

[0024] Preferably, the material of the electron blocking layer in this invention is selected from one of the following materials: .

[0025] Preferably, the material of the hole-blocking layer in this invention is selected from one of the following materials: .

[0026] Preferably, the material of the electron transport layer in this invention is selected from one of the following materials: .

[0027] Preferably, the material of the electron injection layer in this invention is LiF.

[0028] As a cathode layer, the cathode layer material is preferably a material with a low work function in order to facilitate the injection of electrons into the functional organic layer. Specific examples of cathode layer materials that can be used in this invention include: metals or alloys thereof such as magnesium, calcium, sodium, potassium, titanium, indium, yttrium, lithium, gadolinium, aluminum, silver, tin, and lead, for example Mg-Al and Mg-Ag.

[0029] A fourth aspect of the present invention provides a method for fabricating the above-described electroluminescent device. In a specific embodiment, the fabrication method is as follows: an anode layer is adhered to a substrate after pretreatment and cleaning; then, a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, a hole blocking layer, an electron transport layer, and an electron injection layer of predetermined thickness are sequentially vapor-deposited under low-temperature conditions; a cathode layer is then sputtered under low-temperature conditions; and finally, the device is packaged using conventional device packaging methods to obtain the electroluminescent device.

[0030] A fifth aspect of the present invention provides a display panel comprising the electroluminescent device described herein.

[0031] Compared with the prior art, the present invention has the following beneficial effects: The compounds of this invention have a fluorinated conjugated skeleton as the main structure. By introducing a fluorine atom into the central benzene ring, bonding heteroaryl groups (triazine or aziridine ring units) on both sides, and synergistic modification with sterically hindered substituents (e.g., alkyl groups) and fused-ring aryl groups on the periphery, multi-dimensional performance optimization is achieved to meet the core performance requirements of electron transport-type host luminescent materials: the strong electron-withdrawing effect of the fluorine atom and aziridine ring can effectively reduce the molecular LUMO energy level, significantly improve electron injection and transport capabilities, achieve efficient balance of electron-hole carriers within the luminescent layer, and simultaneously suppress intermolecular π-π stacking and aggregation-induced quenching; by controlling the length of the conjugated skeleton and the steric hindrance of the substituents, the extension of the molecular conjugation plane and intermolecular π-π stacking are precisely limited, enabling controllable adjustment of the degree of molecular conjugation, so that the compound possesses a sufficiently high triplet energy level ( E T This technology can effectively match guest light-emitting materials of different wavelengths such as blue and green light, meet exciton confinement requirements, and prevent the energy of guest excitons from relaxing back to the host light-emitting material, thereby improving the luminous efficiency of the device from the root. At the same time, the design of large steric substituents and rigid conjugated framework significantly improves the glass transition temperature and thermal / chemical stability of the material, avoids thin film crystallization and morphology degradation, and thus extends the lifespan of the device.

[0032] The compound of this invention, as an electron transport-type host light-emitting material, possesses both excellent electron transport performance and hole blocking capability, achieving integrated functionality of "electron transport-host light emission-hole blocking". This type of molecule combines high electron mobility, excellent energy level matching, high exciton confinement capability, and good morphological stability. When applied to the light-emitting layer of OLED devices, it can effectively solve the technical problems of low electron mobility, insufficient hole blocking performance, and energy level mismatch between the host light-emitting material and the guest light-emitting material, which lead to limited device luminous efficiency, lifetime, and stability. It can simultaneously improve the luminous efficiency of OLED devices and extend their lifespan. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a cross-sectional view of the electroluminescent device of the present invention; Figure 2 The NMR spectrum of compound 5 of the present invention; Figure 3The NMR spectrum of compound 57 of the present invention; Figure 4 The NMR spectrum of compound 82 of the present invention; Figure 5 The NMR spectrum of compound 106 of the present invention. Detailed Implementation

[0035] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0036] It should be noted that the process equipment or apparatus not specifically mentioned in the following embodiments are all conventional equipment or apparatus in the art.

[0037] It should be noted that the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products, or apparatuses. Furthermore, unless otherwise stated, the numbering of each method step is merely a convenient tool for identifying the method steps, and not intended to limit the order of the method steps or define the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention.

[0038] It should be noted that the English name for high performance liquid chromatography is High Performance Liquid Chromatography, abbreviated as HPLC; and the English name for liquid chromatography-mass spectrometry is Liquid Chromatograph-Mass Spectrometer, abbreviated as LC-MS.

[0039] The key reactants used in this invention are as follows:

[0040]

[0041]

[0042] The specific synthetic route for the important intermediate M1 is shown below:

[0043] The specific synthesis process is as follows: Step 1: Synthesis of intermediate M1-1: Under nitrogen protection, reactant m (27.2 g, 0.1 mol) and 300 mL of anhydrous tetrahydrofuran were added to a 1 L three-necked flask. Stirring was started, and after the reactant was completely dissolved, the system was cooled to -70 °C. At low temperature, a tetrahydrofuran solution of 1.5 M LiHMDS (134 mL, 0.2 mol) was slowly added dropwise. The mixture was then stirred at -70 °C for 1 h, and TLC was used to monitor the reaction of substrate m until it was complete. Anhydrous DMF (19 mL, 0.25 mol) was slowly added dropwise while maintaining the temperature at -70 °C. The mixture was stirred at -78 °C for 30 min, and then the system was allowed to naturally warm to room temperature and stirred for another 12 h. The reaction was then complete. The reaction solution was quenched with saturated NH4Cl aqueous solution, then extracted with ethyl acetate. The organic phase was retained and washed with water. The organic phases were combined, dried over anhydrous sodium sulfate, filtered and concentrated to obtain the residue. The residue was purified by silica gel column chromatography (petroleum ether: dichloromethane = 5:1) to obtain intermediate compound M1-1, weighing 11.5 g, with a yield of 35.1%, HPLC purity of 97%, and LC-MS showing a molecular weight of 327.85.

[0044] Step 2: Synthesis of intermediate M1: Under nitrogen protection, intermediate M1-1 (32.8 g, 0.1 mol), hydrochloride of reactant r1 (78.3 g, 0.5 mol), K2CO3 (55.3 g, 0.4 mol), and 1.5 L of xylene (DMB) were added to a 2 L three-necked flask. Stirring was started, and the mixture was heated to 140 °C in an oil bath. The system became a pale yellow and clear color. The mixture was refluxed for 12 h. After the reaction was complete... The reaction solution was cooled to 60°C and extracted with water. The organic phase was then washed with water, and the combined organic phases were dried with anhydrous sodium sulfate and filtered. The filtrate was added in portions to DDQ (dichlorodicyanoquinone) (29.5 g, 0.13 mol) at 45°C, and the reaction was refluxed for 12 h until completion. The temperature was raised to 80°C, and an aqueous solution of sodium bisulfite was added. The mixture was stirred and washed with water for 5 min, filtered with diatomaceous earth, and the filter cake was washed with water and xylene. The filtrate was retained, and the mixture was separated and extracted while hot. The organic phase was washed with water, dried with anhydrous sodium sulfate, filtered, and concentrated to obtain the residue. The residue was recrystallized from toluene and then purified by silica gel column chromatography (petroleum ether: dichloromethane = 8:1) to obtain intermediate compound M1, weighing 26.1 g, with a yield of 35.5%, HPLC purity of 97%, and LC-MS showing a molecular weight of 734.00.

[0045] The synthesis method of intermediate M2, and the specific synthetic route are shown below:

[0046] The specific synthesis process is as follows: Synthesis of intermediate M2: Under nitrogen protection, intermediate M1-1 (32.8 g, 0.1 mol), hydrochloride of reactant r2 (103.3 g, 0.5 mol), K2CO3 (55.3 g, 0.4 mol), and 1.5 L of xylene were added to a 3 L three-necked flask. Stirring was started, and the mixture was heated to 140 °C in an oil bath. The system was a pale yellow and clear color. The mixture was refluxed for 12 h. After the reaction was complete... The reaction solution was cooled to 60°C and extracted with water. The organic phase was then washed with water, and the combined organic phases were dried with anhydrous sodium sulfate and filtered. The filtrate was added in portions of DDQ (29.5 g, 0.13 mol) at 45°C, and the reaction was refluxed for 12 h to complete the reaction. The temperature was raised to 80°C, and an aqueous solution of sodium bisulfite was added. The mixture was stirred and washed with water for 5 min, filtered with diatomaceous earth, and the filter cake was washed with water and xylene. The filtrate was retained, and the mixture was separated and extracted while hot. The organic phase was washed with water, dried with anhydrous sodium sulfate, filtered, and concentrated to obtain the residue. The residue was recrystallized from toluene and then purified by silica gel column chromatography (petroleum ether: dichloromethane = 8:1) to obtain intermediate compound M2, weighing 34.9 g, with a yield of 37.3%, HPLC purity of 97%, and LC-MS showing a molecular weight of 934.08.

[0047] The synthesis method and specific synthetic route of intermediate M3 are shown below:

[0048] The specific synthesis process is as follows: Step 1: Synthesis of intermediate M3-1: Under nitrogen protection, intermediate M1-1 (32.8 g, 0.1 mol), reactant a1 (29.2 g, 0.2 mol), and 500 mL of ethanol were added to a 1 L three-necked flask. Then, sodium hydroxide dissolved in ethanol and water (2.9 g, 0.12 mol) was added, and the mixture was stirred at 60 °C for 5 h. After the reaction was complete, a solid precipitate formed. The precipitate was filtered and washed, and the filter cake was retained to obtain the crude residue. The residue was dissolved in ethanol by heating, and recrystallized upon cooling to obtain intermediate compound M3-1, weighing 50.0 g, with a yield of 85.6%, HPLC purity of 98%, and LC-MS showing a molecular weight of 583.95.

[0049] Step 2: Synthesis of intermediate M3: Under nitrogen protection, intermediate M3-1 (58.4 g, 0.1 mol), hydrochloride of reactant r1 (39.2 g, 0.25 mol), K2CO3 (55.3 g, 0.4 mol), and 1.5 L of xylene were added to a 2 L three-necked flask. Stirring was started, and the temperature was raised to 140 °C in an oil bath. The system turned pale yellow and clear. The mixture was refluxed for 12 h. After the reaction was completed. The reaction solution was cooled to 60°C and extracted with water. The organic phase was then washed with water, and the combined organic phases were dried with anhydrous sodium sulfate and filtered. The filtrate was added in portions of DDQ (29.5 g, 0.13 mol) at 45°C, and the reaction was refluxed for 12 h to complete the reaction. The temperature was raised to 80°C, and an aqueous solution of sodium bisulfite was added. The mixture was stirred and washed with water for 5 min, filtered with diatomaceous earth, and the filter cake was washed with water and xylene. The filtrate was retained, separated and extracted while hot, and the organic phase was washed with water, dried with anhydrous sodium sulfate, filtered, and concentrated to obtain the residue. The residue was recrystallized from toluene and then purified by silica gel column chromatography (petroleum ether: dichloromethane = 8:1) to obtain intermediate compound M3, weighing 33.9 g, with a yield of 43.5%, HPLC purity of 97%, and LC-MS showing a molecular weight of 780.03.

[0050] The synthesis method and specific synthetic route of intermediate M4 are shown below:

[0051] The specific synthesis process is as follows: Step 1: Synthesis of intermediate M4-1: Under nitrogen protection, reactant m (27.2 g, 0.1 mol) and 300 mL of anhydrous tetrahydrofuran were added to a 1 L three-necked flask. Stirring was started, and after the reactant was completely dissolved, the system was cooled to -78 °C. At low temperature, a 2.5 M n-butyllithium solution in n-hexane (80 mL, 0.2 mol) was slowly added dropwise. Then, the mixture was stirred at -78 °C for 30 min. While maintaining the temperature at -78 °C, N-methoxy-N-methylacetamide (22 mL, 0.2 mol) was added. The mixture was stirred at -78 °C for 1 h. The system was then allowed to naturally warm to room temperature and stirred for another 12 h. The reaction was then complete. The reaction solution was quenched with saturated NH4Cl aqueous solution, then extracted with ethyl acetate. The organic phase was retained and washed with water. The organic phases were combined, dried over anhydrous sodium sulfate, filtered and concentrated to obtain the residue. The residue was purified by silica gel column chromatography (petroleum ether: dichloromethane = 5:1) to obtain intermediate compound M4-1, weighing 10.5 g, with a yield of 29.5%, HPLC purity of 97%, and LC-MS showing a molecular weight of 355.88.

[0052] Step 2: Synthesis of intermediate M4-2: Under nitrogen protection, intermediate M4-1 (17.8 g, 0.05 mol), benzaldehyde (reactant b1, 10.6 g, 0.1 mol), and 200 mL of ethanol were added to a 500 mL three-necked flask. Then, sodium hydroxide dissolved in ethanol and water (1.4 g, 0.06 mol) was added, and the mixture was stirred at 60 °C for 5 h. After the reaction was complete, a solid precipitate formed. The precipitate was filtered and washed, and the filter cake was retained to obtain the crude residue. The residue was dissolved in ethanol by heating, and recrystallized after cooling to obtain intermediate compound M4-2, weighing 21.4 g. The yield was 80.3%, the HPLC purity was 96%, and the LC-MS showed a molecular weight of 531.94.

[0053] Step 3: Synthesis of intermediate M4: Under nitrogen protection, intermediate M4-2 (26.6 g, 0.05 mol), hydrochloride of reactant r1 (15.7 g, 0.1 mol), K2CO3 (27.6 g, 0.2 mol), and 1.0 L of xylene were added to a 2 L three-necked flask. Stirring was started, and the temperature was raised to 140 °C in an oil bath. The system turned pale yellow and clear. The mixture was refluxed for 12 h. After the reaction was completed, the intermediate M4-2 was synthesized. The reaction solution was cooled to 60°C and extracted with water. The organic phase was then washed with water, and the combined organic phases were dried with anhydrous sodium sulfate and filtered. The filtrate was added in portions of DDQ (15.9 g, 0.07 mol) at 45°C, and the reaction was refluxed for 12 h to complete the reaction. The temperature was raised to 80°C, and an aqueous solution of sodium bisulfite was added. The mixture was stirred and washed with water for 5 min, filtered with diatomaceous earth, and the filter cake was washed with water and xylene. The filtrate was retained, separated and extracted while hot, and the organic phase was washed with water, dried with anhydrous sodium sulfate, filtered, and concentrated to obtain the residue. The residue was purified by silica gel column chromatography (petroleum ether: dichloromethane = 8:1) to obtain intermediate compound M4, weighing 14.8 g, with a yield of 40.5%, HPLC purity of 97%, and LC-MS showing a molecular weight of 732.02.

[0054] The synthesis of other intermediates N1, N2, N3, and N4 involved in this invention is based on the synthesis processes of M1, M2, M3, and M4 described above, respectively. During the synthesis, the corresponding starting reactant n is selected to replace reactant m. The structures of intermediates N1, N2, N3, and N4 are shown below:

[0055] The synthetic route for compound 5 is shown below:

[0056] The specific synthesis process is as follows: Synthesis of Compound 5: Under nitrogen protection, intermediate M1 (22.0 g, 0.03 mol), compound C6 (14.0 g, 0.06 mol), Pd(PPh3)4 (0.7 g, 0.6 mmol), K2CO3 (12.4 g, 0.09 mol), 400 mL of 1,4-dioxane, and 100 mL of pure water were added to a 1 L three-necked flask. The system was heated to 80 °C and refluxed for 10 h until the reaction was complete. The reaction solution was washed with water and separated. The organic phase was passed through a diatomaceous earth funnel, and the filtrate was collected. The filtrate was concentrated under reduced pressure to obtain a solid residue. The residue was purified by silica gel column chromatography (petroleum ether: dichloromethane = 10:1) to obtain compound 5, weighing 25.2 g, with a yield of 88.1%, HPLC purity of 98%, and LC-MS showing a molecular weight of 952.50. The NMR spectrum of compound 5 is shown below. Figure 2 As shown.

[0057] 1H NMR data for compound 5: 1 H NMR (500 MHz, DMSO- d 6) δ 8.30–8.24 (m, 8H),7.57–7.45 (m, 14H), 7.15 (d, J = 2.0 Hz, 4H), 1.35 (s, 36H). The synthetic route for compound 26 is shown below:

[0058] The specific synthesis process is as follows: Synthesis of Compound 26: Under nitrogen protection, intermediate M3 (23.4 g, 0.03 mol), compound C11 (10.7 g, 0.06 mol), Pd(PPh3)4 (0.7 g, 0.6 mmol), K2CO3 (12.4 g, 0.09 mol), 1,4-dioxane (400 mL), and pure water (100 mL) were added to a 1 L three-necked flask. The system was heated to 80 °C and refluxed for 10 h until the reaction was complete. The reaction solution was washed with water and separated. The organic phase was passed through a diatomaceous earth funnel, and the filtrate was collected. The filtrate was concentrated under reduced pressure to obtain a solid residue. The residue was purified by silica gel column chromatography (petroleum ether: dichloromethane = 10:1) to obtain compound 26, weighing 22.6 g, with a yield of 85%, HPLC purity of 98%, and LC-MS molecular weight of 886.40.

[0059] The synthesis of compounds 1 to 48 of the present invention is based on the synthesis process of compounds 5 and 26 described above. During the synthesis process, the corresponding intermediates M (M1 to M4) and reactants c (c1 to c18) can be replaced.

[0060] The synthetic route for compound 57 is shown below: The specific synthesis process is as follows: Step 1: Synthesis of Intermediate 57-1: Under nitrogen protection, intermediate N2 (26.7 g, 0.03 mol), compound C4 (4.5 g, 0.03 mol), Pd(PPh3)4 (0.7 g, 0.6 mmol), K2CO3 (12.4 g, 0.09 mol), 1,4-dioxane 400 mL, and pure water 100 mL were added to a 1 L three-necked flask. The system was heated to 80 °C and refluxed for 10 h until the reaction was complete. The reaction solution was washed with water and separated. The organic phase was passed through a diatomaceous earth funnel, and the filtrate was collected. The filtrate was concentrated under reduced pressure to obtain a solid residue. The residue was purified by silica gel column chromatography (petroleum ether: dichloromethane = 10:1) to obtain intermediate compound 57-1, weighing 17.3 g, with a yield of 75.8%, HPLC purity of 98%, and LC-MS showing a molecular weight of 760.20.

[0061] Step 2: Synthesis of Compound 57: Under nitrogen protection, intermediate 57-1 (15.2 g, 0.02 mol), compound C3 (2.7 g, 0.02 mol), Pd132 (dichlorodi-tert-butyl-(4-dimethylaminophenyl)phosphine palladium(II)) (0.3 g, 0.4 mmol), K2CO3 (8.3 g, 0.06 mol), 1,4-dioxane 400 mL, and pure water 100 mL were added to a 1 L three-necked flask. The system was heated to 80 °C and refluxed for 10 h until the reaction was complete. The reaction solution was washed with water and separated. The organic phase was passed through a diatomaceous earth funnel and the filtrate was collected. The filtrate was concentrated under reduced pressure to obtain a solid residue. The residue was purified by silica gel column chromatography (petroleum ether: dichloromethane = 10:1) to obtain compound 57, weighing 15.5 g, with a yield of 80%, HPLC purity of 98%, and LC-MS showing a molecular weight of 970.35. The NMR spectrum of compound 57 is as follows: Figure 3 As shown.

[0062] 1H NMR data for compound 57: 1 H NMR (500 MHz, DMSO- d 6) δ 8.12 (s, 4H), 8.08–8.00 (m, 12H), 7.58–7.49 (m, 12H), 7.32–7.30 (m, 2H), 7.26–7.17 (m, 4H), 7.07–7.06 (m, 1H), 2.40 (t, J = 0.9 Hz, 3H), 2.30 (t, J = 0.9 Hz, 6H). The synthesis of compounds 49 to 80 of the present invention is based on the synthesis process of compound 57 described above. During the synthesis process, the corresponding intermediates N (N1 to N4) and reactants c (c1 to c18) can be replaced.

[0063] The synthetic route for compound 82 is shown below: The specific synthesis process is as follows: Step 1: Synthesis of Intermediate 82-1: Under nitrogen protection, intermediate M1-1 (16.4 g, 0.05 mol), reactant r4 hydrochloride (53.2 g, 0.25 mol), K2CO3 (27.6 g, 0.2 mol), and xylene (1.0 L) were added to a 2 L three-necked flask. Stirring was started, and the mixture was heated to 140 °C in an oil bath. The system turned a pale yellow and clear color. The mixture was refluxed for 12 h. After the reaction was complete... The reaction solution was cooled to 60°C and extracted with water. The organic phase was then washed with water. The combined organic phases were dried with anhydrous sodium sulfate and filtered. The filtrate was added in portions of DDQ (15.9 g, 0.07 mol) at 45°C and refluxed for 12 h to complete the reaction. The temperature was raised to 80°C, and an aqueous solution of sodium bisulfite was added. The mixture was stirred and washed with water for 5 min. The mixture was filtered through diatomaceous earth, and the filter cake was washed with water and xylene. The filtrate was retained, separated and extracted while hot, and the organic phase was washed with water, dried with anhydrous sodium sulfate, filtered, and concentrated to obtain the residue. The residue was purified by silica gel column chromatography (petroleum ether: dichloromethane = 8:1) to obtain intermediate compound 82-1, weighing 19.3 g, with a yield of 40.2%, HPLC purity of 97%, and LC-MS showing a molecular weight of 958.25.

[0064] Step 2: Synthesis of Compound 82: Under nitrogen protection, intermediate 82-1 (19.2 g, 0.02 mol), compound C16 (4.9 g, 0.04 mol), Pd(PPh3)4 (0.5 g, 0.4 mmol), K2CO3 (8.3 g, 0.06 mol), 1,4-dioxane (400 mL), and pure water (100 mL) were added to a 1 L three-necked flask. The system was heated to 80 °C and refluxed for 10 h until the reaction was complete. The reaction solution was washed with water and separated. The organic phase was passed through a diatomaceous earth funnel, and the filtrate was collected. The filtrate was concentrated under reduced pressure to obtain a solid residue. The residue was purified by silica gel column chromatography (petroleum ether: dichloromethane = 10:1) to obtain compound 82, weighing 15.8 g, with a yield of 83%, HPLC purity of 98%, and LC-MS showing a molecular weight of 952.50. The NMR spectrum of compound 82 is shown below. Figure 4 As shown.

[0065] 1H NMR data for compound 82: 1 H NMR (500 MHz, DMSO- d6) δ 1H NMR 7.87-7.84(m, 4H), 7.69 (t, J = 2.0 Hz, 4H), 7.46–7.33 (m, 14H), 7.30-7.27 (m, 4H), 1.33(s, 36H). The synthesis of compounds 81 to 92 of this invention is based on the synthesis process of compound 82 described above. During the synthesis process, the corresponding reactants r (r3 to r14) can be replaced.

[0066] The synthetic route for compound 106 is shown below:

[0067] The specific synthesis process is as follows: Step 1: Synthesis of intermediate 106-1: Under nitrogen protection, intermediate M1-1 (32.8 g, 0.1 mol), reactant a5 (34.8 g, 0.2 mol), and 700 mL of ethanol were added to a 1 L three-necked flask. Then, sodium hydroxide dissolved in ethanol and water (2.9 g, 0.12 mol) was added, and the mixture was stirred at 60 °C for 5 h. After the reaction was complete, a solid precipitate formed. The precipitate was filtered and washed, and the filter cake was retained to obtain the crude residue. The residue was dissolved in ethanol by heating, and recrystallized upon cooling to obtain intermediate compound 106-1, weighing 53.6 g, with a yield of 83.8%, HPLC purity of 98%, and LC-MS showing a molecular weight of 640.03.

[0068] Step 2: Synthesis of Intermediate 106-2: Under nitrogen protection, intermediate 106-1 (32.0 g, 0.05 mol), reactant r10 hydrochloride (49.6 g, 0.25 mol), K2CO3 (27.6 g, 0.2 mol), and xylene (1.0 L) were added to a 2 L three-necked flask. Stirring was started, and the mixture was heated to 140 °C in an oil bath. The system turned a pale yellow and clear color. The mixture was refluxed for 12 h. After the reaction was complete... The reaction solution was cooled to 60°C and extracted with water. The organic phase was then washed with water. The combined organic phases were dried with anhydrous sodium sulfate and filtered. The filtrate was added in portions of DDQ (15.9 g, 0.07 mol) at 45°C and refluxed for 12 h to complete the reaction. The temperature was raised to 80°C, and an aqueous solution of sodium bisulfite was added. The mixture was stirred and washed with water for 5 min. The mixture was filtered through diatomaceous earth, and the filter cake was washed with water and xylene. The filtrate was retained, separated and extracted while hot, and the organic phase was washed with water, dried with anhydrous sodium sulfate, filtered, and concentrated to obtain the residue. The residue was purified by silica gel column chromatography (petroleum ether: dichloromethane = 8:1) to obtain intermediate compound 106-2, weighing 17.1 g, with a yield of 37.2%, HPLC purity of 97%, and LC-MS showing a molecular weight of 920.18.

[0069] Step 3: Synthesis of Compound 106: Under nitrogen protection, intermediate 106-2 (18.4 g, 0.02 mol), compound c16 (4.9 g, 0.04 mol), Pd(PPh3)4 (0.5 g, 0.4 mmol), K2CO3 (8.3 g, 0.06 mol), 400 mL of 1,4-dioxane, and 100 mL of pure water were added to a 1 L three-necked flask. The system was heated to 80 °C and refluxed for 10 h until the reaction was complete. The reaction solution was washed with water and separated. The organic phase was passed through a diatomaceous earth funnel, and the filtrate was collected. The filtrate was concentrated under reduced pressure to obtain a solid residue. The residue was purified by silica gel column chromatography (petroleum ether: dichloromethane = 10:1) to obtain compound 106, weighing 15.9 g, with a yield of 87.1%, HPLC purity of 98%, and LC-MS showing a molecular weight of 914.43. The NMR spectrum of compound 106 is shown below. Figure 5 As shown.

[0070] 1H NMR data for compound 106: 1 H NMR (500 MHz, DMSO- d 6) δ 8.08 (s, 2H), 7.80– 7.74 (m, 4H), 7.68 (s, 2H), 7.48 (s, 2H), 7.46 – 7.33 (m, 10H), 7.26 – 7.19(m, 4H), 6.95 (s, 2H), 2.91 (t, J = 1.0 Hz, 2H), 2.44 (s, 6H), 2.37 (s, 6H), 1.25 (s, 12H). The synthesis of compounds 93 to 112 of the present invention is based on the synthesis process of compound 106 described above. During the synthesis process, the corresponding reactants a (a2 to a7) and reactants r (r3 to r14) can be replaced.

[0071] The synthetic route for compound 115 is shown below:

[0072] Step 1: Synthesis of Intermediate 115-1: Under nitrogen protection, intermediate M4-1 (35.6 g, 0.1 mol), reactant b2 (32.4 g, 0.2 mol), and 600 mL of ethanol were added to a 1 L three-necked flask. Then, sodium hydroxide dissolved in ethanol and water (2.9 g, 0.12 mol) was added, and the mixture was stirred at 60 °C for 5 h. After the reaction was complete, a solid precipitate formed. The precipitate was filtered and washed, and the filter cake was retained to obtain the crude residue. The residue was dissolved in ethanol by heating, and recrystallized after cooling to obtain intermediate compound 115-1, weighing 52.2 g. The yield was 81%, the HPLC purity was 96%, and the molecular weight was 644.05 as shown by LC-MS.

[0073] Step 2: Synthesis of intermediate 115-2: Under nitrogen protection, intermediate 115-1 (32.2 g, 0.05 mol), hydrochloride of reactant r6 (18.5 g, 0.1 mol), K2CO3 (27.6 g, 0.2 mol) and xylene (1.0 L) were added to a 2 L three-necked flask. Stirring was started, and the oil bath temperature was raised to 140 °C. The system was pale yellow and clear. The reaction was refluxed for 12 h. After the reaction was completed, the reaction solution was cooled to 60°C and water was added for extraction. The organic phase was then washed with water, and the combined organic phases were dried with anhydrous sodium sulfate and filtered. The filtrate was added in portions of DDQ (15.9 g, 0.07 mol) at 45°C, and the reaction was refluxed for 12 h to complete the reaction. The temperature was raised to 80°C, and sodium bisulfite aqueous solution was added. The mixture was stirred and washed with water for 5 min, filtered with diatomaceous earth, and the filter cake was washed with water and xylene. The filtrate was retained, separated and extracted while hot, and the organic phase was washed with water, dried with anhydrous sodium sulfate, filtered, and concentrated to obtain the residue. The residue was purified by silica gel column chromatography (petroleum ether: dichloromethane = 8:1) to obtain intermediate compound 115-2, weighing 17.3 g, with a yield of 38.5%, HPLC purity of 97%, and LC-MS showing a molecular weight of 900.20.

[0074] Step 3: Synthesis of Compound 115: Under nitrogen protection, intermediate 115-2 (18.0 g, 0.02 mol), compound C16 (4.9 g, 0.04 mol), Pd(PPh3)4 (0.5 g, 0.4 mmol), K2CO3 (8.3 g, 0.06 mol), 400 mL of 1,4-dioxane, and 100 mL of pure water were added to a 1 L three-necked flask. The system was heated to 80-100 °C and refluxed for 10 h until the reaction was complete. The reaction solution was washed with water and separated. The organic phase was passed through a diatomaceous earth funnel, and the filtrate was collected. The filtrate was concentrated under reduced pressure to obtain a solid residue. The residue was purified by silica gel column chromatography (petroleum ether: dichloromethane = 10:1) to obtain compound 115, weighing 15.9 g, with a yield of 89%, HPLC purity of 98%, and LC-MS showing a molecular weight of 894.45.

[0075] The synthesis of compounds 113 to 120 of the present invention is based on the synthesis process of compound 115 described above. During the synthesis process, the corresponding reactants b (b2 to b7) and reactants r (r3 to c14) can be replaced.

[0076] Using the electroluminescent compound prepared above as the electron transport type host luminescent material, and combining it with a hole transport type host material as the host luminescent material of the luminescent layer, an electroluminescent device is fabricated. A schematic diagram of the electroluminescent device is shown below. Figure 1 As shown, it includes a substrate 1 and an anode layer 2, a hole injection layer 3, a hole transport layer 4, an electron blocking layer 5, a light-emitting layer 6, a hole blocking layer 7, an electron transport layer 8, an electron injection layer 9, and a cathode layer 10, which are sequentially stacked on the substrate 1.

[0077] In the specific fabrication process of the electroluminescent device, CBP was used as the hole transport type host luminescent material, and compounds 2, 5, 9, 12, 13, 21, 23, 26, 31, 33, 38, 47, 52, 55, 57, 61, 69, 73, 77, 79, 82, 87, 91, 93, 97, 101, 106, 109, 115, and 119 were used as electron transport type host luminescent materials, and compound PD-1 was used as the guest luminescent material. The mass ratio of the hole transport type host luminescent material, the electron transport type luminescent material, and the guest luminescent material was 49:49:2.

[0078] In the electroluminescent device, from the anode layer to the cathode layer, the following layers are sequentially stacked: PET plastic, ITO, MoO3, TAPC, mCP, light-emitting layer, HB-1, TmPyPB, LiF, and Al.

[0079] The functional layer material structure used in the fabrication process of the electroluminescent device is as follows:

[0080] Application Examples 1-30 A method for fabricating an organic electroluminescent device includes the following steps: 1. Using 1.5mm PET plastic as substrate 1 and 150nm ITO material as anode layer 2, the substrate is washed in sequence by alkaline washing, pure water washing, drying, and then ultraviolet-ozone washing to remove organic residues on the surface of PET plastic and ITO material.

[0081] 2. A layer of ITO material is adhered to PET plastic. Using a vacuum evaporation apparatus, a 10 nm thick MoO3 film is deposited as a hole injection layer 3. Then, a 50 nm thick TAPC film is deposited as a hole transport layer 4. Subsequently, a 20 nm thick mCP film is deposited as an electron blocking layer 5. A 40 nm thick light-emitting layer 6 is then deposited on the electron blocking layer 5. The light-emitting layer 6 is co-deposited according to a ratio of 49:49:2 for hole transport type host light-emitting material: electron transport type host light-emitting material: guest light-emitting material. A 10 nm thick HB-1 film is then deposited on the light-emitting layer 6 as a hole blocking layer 7. Next, a 30 nm thick TmPyPB film is deposited as an electron transport layer 8. Then, a 1 nm thick LiF film is deposited on the electron transport layer 8 as an electron injection layer 9. After the electron injection layer 9 is deposited, a 100 nm thick Al film is sputtered as a cathode layer 10 using a low-temperature sputtering method.

[0082] 3. Vacuum encapsulation of MoO3, TAPC, mCP, light-emitting layer, ET-1, TmPyPB and LiF layer to prepare an electroluminescent device.

[0083] Among them, the electron transport type host luminescent materials are compounds 2, 5, 9, 12, 13, 21, 23, 26, 31, 33, 38, 47, 52, 55, 57, 61, 69, 73, 77, 79, 82, 87, 91, 93, 97, 101, 106, 109, 115 and 119, respectively, corresponding to application examples 1 to 30.

[0084] Comparative Application Example 1 The fabrication method of the electroluminescent device is the same as the application example above, except that the structure of the electroluminescent device is as follows: PET / ITO / MoO3 / TAPC / mCP / CBP:BH-1:PD-1=49:49:2 / HB-1 / TmPyPB / LiF / Al.

[0085] Comparative Application Example 2 The fabrication method of the electroluminescent device is the same as the application example above, except that the structure of the electroluminescent device is as follows: PET / ITO / MoO3 / TAPC / mCP / CBP:BH-2:PD-1=49:49:2 / HB-1 / TmPyPB / LiF / Al.

[0086] Comparative Application Example 3 The fabrication method of the electroluminescent device is the same as the application example above, except that the structure of the electroluminescent device is as follows: PET / ITO / MoO3 / TAPC / mCP / CBP:BH-3:PD-1=49:49:2 / HB-1 / TmPyPB / LiF / Al.

[0087] The structures of BH-1, BH-2, and BH-3 are as follows: .

[0088] The electroluminescent devices from the above application examples and comparative application examples were fabricated into 30mm × 30mm samples. Then, under the same device fabrication process conditions, the anode and cathode layers were connected using an industry-known driving circuit, and the luminous performance indicators of each electroluminescent device were tested. For the electroluminescent devices, at 10mA / cm... 2 The driving voltage and luminous efficiency were measured at a current density of 20 mA / cm². 2 The time required for the brightness to become 95% of its initial brightness at a given current density (LT) 95 (i.e., lifespan). The test results are shown in Table 1.

[0089] Table 1. Performance data of the electroluminescent devices fabricated in the comparative application examples and application examples.

[0090] Note: Here, EQE refers to 1000 cd / m 2 External quantum efficiency at operating brightness.

[0091] As can be seen from the performance data in Table 1, compared with the electroluminescent devices prepared using the host luminescent materials BH-1, BH-2 and BH-3 in the comparative application examples (comparative application examples 1 to 3), the electroluminescent devices prepared using the electroluminescent compound of the present invention as the electron transport type host luminescent material have significantly improved overall luminous efficiency, with an external quantum efficiency improvement of about 50% and an extended service life.

[0092] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of this invention.

Claims

1. An electroluminescent compound, characterized in that, Its structure is shown in Equation 1: R1 and R2 are independently selected from substituted or unsubstituted C6~C6 cells, respectively. 20 The aryl group; R1 and R2 may be the same or different; Ar1 and Ar2 are independently selected from the substituted C3~C. 20 heteroaryl groups; the C3~C 20 The substituents of the heteroaryl group are selected from substituted or unsubstituted phenyl groups, substituted or unsubstituted naphthyl groups, and C1-C2 groups. 10 Alkyl groups; the C3~C 20 The heteroatom in the heteroaryl group contains at least one nitrogen atom.

2. The electroluminescent compound according to claim 1, characterized in that, The C6~C 20 When the aryl group is replaced by a substituent, the substituent is selected from C1 to C2. 10 Alkyl, C1~C 10 alkoxy groups.

3. The electroluminescent compound according to claim 1, characterized in that, In Formula 1, R1 and R2 are independently selected from the following groups A1 to A18: Among the groups A1~A18, "Indicates R1, R2 and the main structure The bonding positions.

4. The electroluminescent compound according to claim 1, characterized in that, The C3~C 20 The heteroaryl group is selected from triazine, pyrimidine, .

5. The electroluminescent compound according to claim 1, characterized in that, When the phenyl and naphthyl groups are substituted with substituents, the substituents are selected from C1 to C2. 10 Alkyl groups.

6. The electroluminescent compound according to claim 1, characterized in that, The electroluminescent compound is one of the following compounds 1 to 120: 。 7. An electroluminescent device, characterized in that, The system comprises a cathode layer, an anode layer, and an organic layer located between the cathode layer and the anode layer; the organic layer, from the anode layer to the cathode layer, sequentially comprises a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, a hole blocking layer, an electron transport layer, and an electron injection layer; the light-emitting layer comprises a host light-emitting material and a guest light-emitting material, the host light-emitting material comprising a hole transport type host light-emitting material and an electron transport type host light-emitting material, the electron transport type host light-emitting material comprising the electroluminescent compound according to any one of claims 1 to 6.

8. The electroluminescent device according to claim 7, characterized in that, The guest luminescent material is selected from one of the following compounds: 。 9. The electroluminescent device according to claim 7, characterized in that, The hole-transporting host luminescent material is selected from any one of the following compounds: 。 10. The electroluminescent device according to claim 7, characterized in that, The mass ratio of the hole-transporting main luminescent material to the electron-transporting main luminescent material is 1:1.

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