Organic electroluminescent material and organic electroluminescent device comprising same

Abstract

The invention provides an organic electroluminescent material and an organic electroluminescent device comprising the same, and belongs to the field of organic photoelectric materials, and the organic electroluminescent material has a structure shown in a general formula I. The organic electroluminescent material provided by the invention is used as a material of a luminescent layer of the organic electroluminescent device, and the luminescent layer has a good luminescent effect. The driving voltage of the device can be reduced, the maximum external quantum efficiency of the device can be improved, and the phosphorescence lifetime of the device can be prolonged.

Description

Technical Field

[0001] This invention belongs to the field of organic optoelectronic materials, specifically relating to an organic electroluminescent material and an organic electroluminescent device containing the same. Background Technology

[0002] Organic light-emitting diodes (OLEDs) are devices that convert electrical energy into light by applying electricity to organic light-emitting materials. They generally have a structure comprising an anode, a cathode, and an organic layer between the anode and cathode. The organic layer of an organic EL device can consist of a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer (containing a host material and dopant materials), an electron buffer layer, a hole blocking layer, an electron transport layer, and an electron injection layer. The materials used in the organic layer are classified according to their function as hole injection materials, hole transport materials, electron blocking materials, light-emitting materials, electron buffer materials, hole blocking materials, electron transport materials, and electron injection materials. In the organic EL device, due to the application of voltage, holes are injected into the light-emitting layer from the anode, and electrons are injected into the light-emitting layer from the cathode. The recombination of holes and electrons forms high-energy excitons. With this energy, the organic light-emitting compound reaches an excited state, and light is emitted by the energy generated when the excited state of the organic light-emitting compound returns to its ground state.

[0003] However, existing organic electroluminescent materials suffer from low stability and poor matching between HOMO and LUMO energy levels and adjacent energy levels, leading to an imbalance in carrier mobility. This results in organic electroluminescent devices containing these materials exhibiting high driving voltage, low luminous efficiency, and short lifetime, severely limiting their applications. Therefore, developing a high-performance luminescent material that combines high efficiency, long lifetime, and low voltage in organic electroluminescent devices is a pressing technical problem that needs to be solved by those in the field. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide an organic electroluminescent material and an organic electroluminescent device comprising the same. Using the organic electroluminescent material provided by the present invention as the material of the light-emitting layer of an organic electroluminescent device not only reduces the driving voltage of the device but also improves the maximum external quantum efficiency and extends the phosphorescence lifetime of the device.

[0005] To achieve this objective, the present invention adopts the following technical solution: On one hand, the present invention provides an organic electroluminescent material having the structure shown in general formula I: ; The structure of the organic electroluminescent material can be represented as: M(LA)2 (Formula II); R1, R2 and R4 are independently selected from any one or a combination of at least two of -H, -D, -F, -CD3, -CN, adamantane, C1-C10 alkyl groups wholly or partially substituted with deuterium, substituted or unsubstituted C6-C18 aryl groups, substituted or unsubstituted C6-C18 heteroaryl groups, substituted or unsubstituted C3-C10 cycloalkyl groups, -Si(Me)3, and -Ge(Me)3. R1, R2, R3, and R4 exist independently or are fused together or with each other at any position in the ring, or form cyclic groups together or with the ring. When substituted independently, R3 is selected from tert-butyl; R5, R7, R8, R9 and R 10 Each is independently selected from any one or a combination of at least two of the following: halogen, silanyl, silyl, adamantyl, carbazole, quinolinyl, methoxy, triazine, dibenzothiophene, benzothiophene, dibenzofuran, diphenylamino, -H, -D, -CD3, -CF3, -CN, -NO2, C1-C10 alkyl, C3-C10 cycloalkyl, C6-C18 aryl, C6-C18 heteroaryl, -Si(Me)3, -Ge(Me)3, and 4- to 18-membered heterocyclic groups; R5, R7, R8, R9 and R 10 They can exist independently or be fused together with each other or with any position in the ring, or form cyclic groups with each other or with the ring. When used as an independent substitution, R6 is selected from -CN; R5, R6, R7, R8, R9 and R 10 When cyclization occurs, the resulting rings are: benzene ring, naphthyl ring, pyridine ring, 1,1-dimethyl-2,3-dihydro-1-benzosilyl pentene ring, 1,1-dimethyl-2,3-dihydro-1-benzogermanium pentene ring, 2,3-dihydrobenzofuran ring, 2,3-dihydrobenzothiophene ring, quinoline ring, 9,10-dihydrophenanthrene ring, cyclohexane, and biphenyl ring; The above groups are either unsubstituted or substituted; The substitution refers to substitution by a substituent selected from one or more of the following groups linked together: -D, -F, -CD3, -CF3, methyl, ethyl, propyl, butyl, pentyl, hexyl, cyclopropyl, cyclobutyl, cyclopentyl, dimethylcyclopentyl, cyclohexyl, silyl, germanyl, 1,1-dimethylindanyl.

[0006] W is independently selected from SiR'R''; wherein R' and R'' are selected from halogens, -CN, -D, substituted or unsubstituted C1-C10 alkyl, substituted or unsubstituted C6-C18 aryl, substituted or unsubstituted C3-C10 cycloalkyl, quinolinyl, and benzothiophene. R 11 R 12 R 13 R 14 R 15 R 16 R 17 and R 18 Independently selected from -H, -D, -CD3, -CN, -CF3, -NO2, -Si(Me)3, -Ge(Me)3, halogen, benzodimethylsilyl, benzodimethylgermanyl, methoxy, adamantyl, nitro, 1,1-dimethyl-2,3-dihydro-1H-indene-substituted naphthyl, cyano and phenyl-substituted naphthyl, dimethylcyclohexyl, siloxane, fluorenyl, phenanthrene, anthracene, indene, triphenylene, triazine, pyrene, tetraphenyl, perylene, trefyl, condensed tetraphenyl The following are all groups of phenyl, fluoranthryl, furanyl, thiophene, pyridyl, pyrimidinyl, benzofuranyl, benzothiophene, isobenzofuranyl, dibenzofuranyl, dibenzothiophene, quinolinyl, isoquinolinyl, quinazolinyl, carbazole, phenanthridine, benzom-dioxacyclopentenyl, C1-C10 alkyl, C3-C10 cycloalkyl, C3-C10 heterocyclic, substituted or unsubstituted C6-C18 aryl, substituted or unsubstituted C6-C18 heteroaryl; R 11 R 12 R 13 R 14 R 15 R 16 R 17 and R 18 They can exist independently or fuse with each other or at any position in the ring and can form cyclic groups with each other or with the ring. The substitution in the context of substituted or unsubstituted means substitution by a substituent selected from one or more of the following groups linked together: -D, -F, -CD3, -CF3, methyl, ethyl, propyl, butyl, pentyl, hexyl, cyclopropyl, cyclobutyl, cyclopentyl, dimethylcyclopentyl, cyclohexyl, silyl, germanyl, 1,1-dimethylindanyl.

[0007] Furthermore, R1, R2, and R4 are independently selected from any one or at least two combinations of methyl, ethyl, propyl, butyl, pentyl, phenyl, -H, -CN, -D, -F, -CD3, -Si(Me)3, -Ge(Me)3, adamantane, phenyl, cyclopropyl, cyclobutyl, and cyclopentyl; R1, R2, and R4 exist independently or are fused with each other or at any position on the ring, or form cyclic groups with each other or on the ring. When substituted independently, R3 is selected from tert-butyl; R5, R7, R8, R9 and R 10 Each of the following is independently selected from any one or a combination of at least two of the following: -H, -D, -CD3, -CF3, -CN, -NO2, -CN, -F, -Si(Me)3, -Ge(Me)3, methyl, ethyl, propyl, butyl, pentyl, phenyl, cyclopropyl, cyclobutyl, cyclopentyl, biphenyl, silanyl, siloxane, adamantyl, carbazolyl, quinolinyl, naphthyl, methoxy, triazine, dibenzothiophene, benzothiophene, dibenzofuranyl, diphenylamino, and benzo-m-dioxacyclopentenyl. When used as an independent substitution, R6 is selected from -CN. R5, R6, R7, R8, R9 and R 10 When cyclization occurs, the resulting rings are: benzene ring, naphthyl ring, pyridine ring, 1,1-dimethyl-2,3-dihydro-1-benzosilyl pentene ring, 1,1-dimethyl-2,3-dihydro-1-benzogermanium pentene ring, 2,3-dihydrobenzofuran ring, 2,3-dihydrobenzothiophene ring, quinoline ring, 9,10-dihydrophenanthrene ring, cyclohexane, and biphenyl ring; R 11 R 12 R 13 R 14 R 15 R 16 R 17 and R 18 Independently selected from any one or at least two combinations of methyl, ethyl, propyl, butyl, pentyl, phenyl, methoxy, -H, -D, -F, -CD3, -NO2, -CN, -Si(Me)3, -Ge(Me)3, -CF3, benzodimethylsilyl, benzodimethylgermanium, adamantyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, quinolinyl, carbazole, 1,1-dimethyl-2,3-dihydro-1H-indenyl-substituted carbazole, naphthyl, thiophene, triazine, benzothiophene, furanyl, benzofuranyl, biphenyl, isobenzofuranyl, dibenzofuranyl, dibenzothiophene, isoquinolinyl, quinazolinyl, cyano and phenyl-substituted naphthyl, dimethylcyclohexyl, siloxane, R 11 R 12 R 13 R14 R 15 R 16 R 17 and R 18 Two groups, either existing independently or adjacent to each other, can fuse together to form a cyclic structure.

[0008] W is independently selected from SiR'R''; wherein R' and R'' are selected from -F, -D, -CN, methyl, phenyl, cyclopropyl, cyclopentyl, biphenyl, naphthyl, quinolinyl, or benzothiophene.

[0009] In this invention, C1-C10 can be C1, C2, C3, C4, C5, C6, C7, C8, C9 or C10, C6-C18 can be C6, C7, C8, C9, C10, C11, C12, C13, C14, C16 or C18, etc., and C3 to C10 can be C3, C4, C5, C6, C7, C8, C9 or C10.

[0010] Furthermore, the ligand LA is selected from any one of the following structures: ; The dashed lines represent the ligand attachment sites.

[0011] Furthermore, the specific structure of the ligand II is as follows: .

[0012] In this invention, the organic electroluminescent material is selected from any combination of LA and Formula II, and is not limited to any of the following structures: .

[0013] A second objective of this invention is to provide a method for preparing the organometallic compound as described above.

[0014] In this invention, the preparation process of the organometallic compound with formula I is as follows: ; Among them, R1, R2, R3, R4, R5, R6, R7, R8, R9, R 10 R 11 R 12 R 13 R 14 R 15 R 16 R 17 R 18 As defined above, W is consistent with the definition above and will not be repeated here.

[0015] The preparation process is as follows: Under nitrogen protection, ligand V and IrCl3·3H2O were placed into the reaction system, and a mixed solution of ethylene glycol ethyl ether and purified water was added. The mixture was refluxed at 110-130℃ for 24-48 hours under nitrogen protection to obtain intermediate IV. Add silver trifluoromethanesulfonate to intermediate formula IV, then add dichloromethane and methanol to the system, and reflux at 20-30°C for 24-48 hours under nitrogen protection to obtain intermediate formula III; Add ligand II to intermediate formula III, then add anhydrous ethanol to the system, and reflux at 79-90°C for 24-48 hours under nitrogen protection to obtain the organometallic compound shown in formula I.

[0016] A third technical objective of this invention is to provide an organic electroluminescent device, the organic electroluminescent device comprising an anode, a cathode, and an organic material layer disposed between the anode and the cathode, the organic material layer comprising at least one of the organic electroluminescent materials described above.

[0017] Preferably, the organic material layer includes a light-emitting layer, which includes a host material and a dopant material, wherein the dopant material includes at least one of the organic electroluminescent materials described above.

[0018] Preferably, the organic material layer further includes at least one of a hole injection layer, a hole transport layer, an electron blocking layer, an electron transport layer, or an electron injection layer.

[0019] Preferably, the organic electroluminescent device comprises an anode, a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, an electron transport layer, an electron injection layer, and a cathode arranged sequentially.

[0020] Generally, organic electroluminescent devices include a first electrode (anode) and a second electrode (cathode), as well as an organic material layer located between the electrodes. This organic material can be further divided into multiple regions. For example, the organic material layer may include a hole transport region, a light-emitting layer, and an electron transport region.

[0021] In specific embodiments, a substrate can be used below the first electrode or above the second electrode. The substrate is typically made of glass or polymer material with excellent mechanical strength, thermal stability, water resistance, and transparency. Furthermore, thin-film transistors (TFTs) can also be incorporated into the substrate used for displays.

[0022] The first electrode can be formed by sputtering or depositing a material for use as the first electrode on a substrate. When the first electrode is used as the anode, it can be a transparent conductive oxide material such as indium tin oxide (ITO), indium zinc oxide (IZO), tin dioxide (SnO2), zinc oxide (ZnO), or any combination thereof. Furthermore, the anode material can also be selected from materials and combinations thereof that facilitate hole injection, in addition to the anode materials already listed, including known materials suitable for use as anodes. When the first electrode is used as the cathode, it can be a metal or alloy such as magnesium (Mg), silver (Ag), aluminum (Al), aluminum-lithium (Al-Li), calcium (Ca), magnesium-indium (Mg-In), magnesium-silver (Mg-Ag), or any combination thereof. Besides the cathode materials listed above, the cathode material can also be a material and combination thereof that facilitates electron injection, including known materials suitable for use as cathodes.

[0023] The organic material layer can be formed on the electrode using methods such as vacuum thermal evaporation, spin coating, and printing. The compounds used as the organic material layer can be small organic molecules, large organic molecules, polymers, and combinations thereof. The hole transport region is located between the anode and the light-emitting layer. The hole transport region can be a monolayer hole transport layer (HTL), including monolayer hole transport layers containing only one compound and monolayer hole transport layers containing multiple compounds. The hole transport region can also be a multilayer structure including at least one of a hole injection layer (HIL), a hole transport layer (HTL), and an electron blocking layer (EBL).

[0024] The material of the hole transport layer may be selected from, but is not limited to, phthalocyanine derivatives such as CuPc, conductive polymers or polymers containing conductive dopants such as polyphenylene ethylene, polyaniline / dodecylbenzenesulfonic acid (PANI / DBSA), poly(3,4-ethylenedioxythiophene) / poly(4-styrenesulfonate) (PEDOT / PSS), polyaniline / camphorsulfonic acid (PANI / CSA), polyaniline / poly(4-styrenesulfonate) (PANI / PSS), aromatic amine derivatives as shown in HT-1 to HT-30 below, or any combination thereof.

[0025] .

[0026] The hole injection layer is located between the anode and the hole transport layer. The hole injection layer can be a single compound material or a combination of multiple compounds. For example, the hole injection layer can use one or more compounds from HT-1 to HT-30 described above, or one or more compounds from HI-1 to HI-3 described below; alternatively, one or more compounds from HT-1 to HT-30 described above can be doped with one or more compounds from HI-1 to HI-3 described below. .

[0027] The OLED organic material layer may also include an electron transport region between the light-emitting layer and the cathode. The electron transport region can be a single-layer electron transport layer (ETL), including single-layer electron transport layers containing only one compound and single-layer electron transport layers containing multiple compounds. Alternatively, the electron transport region can be a multilayer structure including at least one of an electron injection layer (EIL), an electron transport layer (ETL), and a hole blocking layer (HBL).

[0028] The electron transport layer material may be selected from, but is not limited to, one or a combination of at least two of the following: ET-1 to ET-36. .

[0029] The device may also include an electron injection layer located between the electron transport layer and the cathode, wherein the electron injection layer material includes, but is not limited to, one or more combinations of the following: LiF, NaCl, CsF, Li2O, Cs2CO3, BaO, Na, Li, Ca.

[0030] Compared with the prior art, the present invention has the following beneficial effects: Through comparison, this invention shows that fixing the R6 position to -CN has the following core advantages: 1. Enhanced molecular rigidity and planarity: The strong electron-withdrawing properties and steric hindrance of the cyano group can suppress intramolecular rotation and reduce nonradiative transition losses, thereby improving fluorescence quantum yield; 2. Regulation of molecular energy levels and emission color: As a strong electron-withdrawing group, the cyano group can lower the LUMO energy level of the molecule and narrow the HOMO-LUMO energy level difference; 3. Improve material stability and carrier transport performance: Cyano groups can enhance intermolecular interactions, improve film formation properties, and optimize electron transport capabilities, making them suitable for the performance requirements of devices such as electromechanical light-emitting diodes (OLEDs); When the R3 position is fixed at tert-butyl, the core benefits are concentrated in two aspects: structural control and performance optimization. 1. Inhibit molecular aggregation and reduce quenching: Tert-butyl has a large steric hindrance, which can effectively hinder the π-π stacking effect between molecules, avoid fluorescence quenching caused by the formation of aggregated states, and improve the luminescence efficiency of materials in solid or concentrated solutions.

[0031] 2. Improve material stability and processing performance: The hydrophobic properties and steric protection of tert-butyl groups can enhance the thermal and chemical stability of molecules; at the same time, they can improve the solubility of materials in organic solvents, which facilitates the film formation process in device fabrication.

[0032] 3. Fine-tuning of luminescence performance: Compared with strong electron-withdrawing / donating groups, tert-butyl is a weak electronic effect group. Its introduction will not significantly change the HOMO-LUMO energy level difference of the molecule. It can optimize device performance while basically maintaining the original luminescence color, and the driving voltage is significantly reduced, resulting in a significant improvement in luminescence efficiency and lifetime. Attached Figure Description

[0033] Figure 1 The 1H NMR spectrum of compound Z-1 prepared in Example 1. Detailed Implementation

[0034] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0035] Example 1 Under nitrogen protection, (4-tert-butylpyridin-2-yl)boric acid (1 eq, CAS: 1446316-78-4) and anhydrous potassium carbonate (3 eq, CAS: 584-08-7) were added to the reaction system, along with toluene, anhydrous ethanol, and purified water. Under nitrogen protection, Pd(PPh3)4 (tetra(triphenylphosphine)palladium) (0.015 eq, CAS: 14221-01-3) was added in three batches every hour. S:56961-77-4), after addition, refluxed at 80℃ for 24h under nitrogen protection, then cooled to 25℃. After the reaction cooled, it was extracted with ethyl acetate, washed three times with saturated brine, dried over anhydrous magnesium sulfate, concentrated under reduced pressure, and the crude product was column-chromatographically analyzed (200-300 mesh, 500g) to remove impurities. The developing solvent was EA (ethyl acetate):PE (petroleum ether) in a volume ratio of 1:15. The receiving liquid was vortexed until no liquid flowed out, dried under vacuum, and compound intermediate 1 was obtained with a yield of 51.6%. Under nitrogen protection, 4-chlorobenzonitrile (1 eq, CAS: 623-03-0) and K3PO4·3H2O (3 eq, CAS: 7778-53-2) were added to the reaction system. 1,4-Dioxane was added, followed by DBA palladium (tris(dibenzylacetone)dipalladium, (0.01 eq, CAS: 52409-22-0)) and S-Phos (2-dicyclohexylphosphine-2',6'-dimethoxybiphenyl, 0.1 eq, CA) under nitrogen protection. S:657408-07-6) Add pinacol diboronic acid ester (2 eq, CAS:73183-34-3) in three batches every hour. After the addition is complete, reflux at 100°C for 36 h under nitrogen protection, then cool to 25°C and concentrate under reduced pressure. Column chromatography (200-300 mesh, 500 g) is used to remove impurities. The developing solvent is EA:PE (volume ratio) = 1:20. The receiving liquid is vortexed until no liquid flows out, and then dried under vacuum to obtain compound intermediate 2 with a yield of 90.6%. Under nitrogen protection, intermediate 1 (1 eq) and anhydrous potassium carbonate (3 eq, CAS: 584-08-7) were added to the reaction system, along with toluene, anhydrous ethanol, and purified water. Under nitrogen protection, Pd(PPh3)4 (tetra(triphenylphosphine)palladium) (0.015 eq, CAS: 14221-01-3) was added. Intermediate 2 (1 eq) was added in three batches every hour. After the addition was complete, the mixture was refluxed at 80°C for 24 hours under nitrogen protection, then cooled to 25°C. After the reaction cooled, the mixture was extracted with ethyl acetate, washed three times with saturated brine, dried over anhydrous magnesium sulfate, and concentrated under reduced pressure. The crude product was then subjected to column chromatography (200-300 mesh, 500 g) to remove impurities. The developing solvent was EA:PE (volume ratio) = 1:12. The receiving liquid was vortexed until no liquid flowed out, and then dried under vacuum to obtain compound intermediate 3, with a yield of 47.3%. Intermediate 3 (1 eq) was dissolved in 100 mL of dry THF. Under nitrogen protection, the mixture was cooled to 78 °C with liquid nitrogen. A 2.5 M n-butyllithium hexane solution (1 eq, CAS: 109-72-8) was added dropwise, and the mixture was stirred for 1 hour. The temperature was then raised to 40 °C and stirred for 1 hour. The temperature was then lowered to 78 °C, and dichlorodimethylsilane (1 eq, CAS: 75-78-5) was added dropwise. The mixture was stirred for 1 hour, and then heated to room temperature and stirred for 2 hours. A saturated ammonium chloride aqueous solution (2.5 eq, CAS: 12125-02-9) was added dropwise. The mixture was extracted with ethyl acetate, and the organic phase was collected, dried, filtered, and the filtrate was concentrated to dryness under reduced pressure. The crude product was subjected to column chromatography (200-300 mesh, 500 g) to remove impurities. The developing solvent was EA:PE (volume ratio) = 1:10. The receiving liquid was vortexed until no liquid flowed out and dried under vacuum to obtain the intermediate of the compound shown in Formula II-1, with a yield of 43.5%. Under nitrogen protection, compound V-1 (5-tert-butyl-2-phenylpyridine, 1 eq, CAS: 92646-00-9) and IrC13·3H2O (0.4 eq, CAS: 14996-61-3) were weighed and added to the reaction system. A mixed solution of ethylene glycol ethyl ether and purified water was added, and the mixture was refluxed at 120°C for 36 hours under nitrogen protection. Then, it was cooled to room temperature, and a precipitate was formed. The precipitate was filtered, washed with water, anhydrous ethanol, and petroleum ether in sequence, and dried to obtain the compound shown in formula IV-1, with a yield of 81.3%. Under nitrogen protection, compound IV-1 (1 eq) was weighed, silver trifluoromethanesulfonate (2.2 eq, CAS: 2923-28-6) was added, followed by dichloromethane and methanol. The mixture was refluxed at 25°C for 36 hours under nitrogen protection, cooled to room temperature, and the column chromatography filtrate was concentrated until a solid precipitated to obtain compound III-1 with a yield of 91.2%. Under nitrogen protection, compound III-1 (1 eq) was weighed and compound II-1 (2.2 eq) was added. Anhydrous ethanol was then added to the system, and the mixture was refluxed at 80°C for 36 hours under nitrogen protection. The mixture was then filtered, washed with ethanol, and dried. Dichloromethane was used as a solvent, and silica gel column chromatography was performed. The filtrate was concentrated and the solid precipitated to give the final compound Z-1, with a yield of 62.1%.

[0036] HPLC purity: greater than 99.5%; MS(ESI, m / Z): [M+H] + : 980.51.

[0037] The proton NMR spectrum of compound Z-1 prepared in Example 1 is shown below. Figure 1 As shown.

[0038] In addition, it should be noted that other compounds of the present invention can be obtained by referring to the preparation methods of the examples listed above, and will not be described in detail here.

[0039] Device Example 1: Fabrication of an organic electroluminescent device using an organometallic compound of formula Z-1 The ITO glass substrate with a coating thickness of 1500 Å was washed twice in distilled water and ultrasonically washed for 30 minutes. After the distilled water washing was completed, it was ultrasonically washed in the order of isopropanol, acetone, methanol and other solvents, and then dried. It was then transferred to a plasma cleaning machine and washed for 10 minutes before being sent to a vapor deposition machine.

[0040] First, a hole injection layer of HI-1 with a thickness of 100 Å is deposited on the ITO (anode). Then, a hole transport layer of HT-4 with a thickness of 900 Å is deposited on the hole injection layer. Next, a light-emitting layer of 4,4'-N,N'-dicarbazole biphenyl ("CBP") and dopant compound Z-1 with a thickness of 400 Å in a weight ratio of 90:10 is deposited. Then, an electron transport layer of ET-4 with a thickness of 400 Å is deposited on the light-emitting layer. Next, an electron injection layer of Liq with a thickness of 150 Å is deposited on the electron transport layer. Finally, a cathode material of Al with a thickness of 1000 Å is deposited on the electron injection layer to obtain the organic electroluminescent device.

[0041] The structure of Liq is as follows: The performance and luminescence characteristics of the obtained devices were tested using a KEITHLEY 2400 source measurement unit and a CS-2000 spectroradiometer to evaluate the driving voltage, lifetime, and luminous efficiency.

[0042] Device Comparison Example 1-22: The organic electroluminescent device was prepared using the same method as in Device Example 1. The structure of the green doped compound in the emitting layer is as follows: Device Examples 2-42: The method described in Embodiment 1 of the above device is the same, except that the doped material compound Z-1 replaces Z-9, Z-19, Z-23, Z-44, Z-58, Z-65, Z-68, Z-73, Z-77, Z-79, Z-81, Z-85, Z-88, Z-91, Z-93, Z-95, Z-97, Z-98, Z-102, Z-105, Z-110, Z-115, and Z-1, respectively. 21, Z-130, Z-139, Z-145, Z-149, Z-152, Z-161, Z-167, Z-168, Z-170, Z-172, Z-174, Z-181, Z-188, Z-195, Z-207, Z-211, Z-220, Z-222, and then organic electroluminescent devices (Device Examples 2-42) were prepared using the same method as Device Example 1.

[0043] The driving voltage, luminous efficiency, and lifetime of the organic electroluminescent devices obtained from the above-mentioned device embodiments and device comparative examples were characterized at a brightness of 15000 nits. The test results are shown in Table 1.

[0044] It should be noted that a relative value is a comparison between two numbers. Relative values ​​are usually expressed as a percentage or decimal and are used to indicate the degree of change of one number relative to other numbers. In addition, in the industrial field, relative values ​​can also be used to measure the degree of change in production efficiency, as well as to evaluate the quality and stability of products.

[0045] Table 1 As can be seen from Table 1: 1. By comparing Comparative Examples 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, and 22 with the organic electroluminescent materials Z-1, Z-9, Z-19, Z-23, Z-44, Z-58, Z-65, Z-68, Z-73, Z-77, Z-79, Z-81, Z-85, Z-88, Z-91, Z-93, Z-95, Z-97, Z-98, Z-102, Z-105, Z-110, and Z-115 of the present invention... A comparison of Z-121, Z-130, Z-139, Z-145, Z-149, Z-152, Z-161, Z-167, Z-168, Z-170, Z-172, Z-174, Z-181, Z-188, Z-195, Z-207, Z-211, Z-220, and Z-222 shows that fixing the -CN position enhances molecular rigidity and planarity; the strong electron-withdrawing properties and steric hindrance effect of the cyano group can suppress intramolecular rotation, reduce nonradiative transition losses, and thus improve fluorescence quantum yield; and regulate molecular energy levels and... Emission color: As a strong electron-withdrawing group, the cyano group can lower the LUMO energy level of the molecule and narrow the HOMO-LUMO energy level difference; Improved material stability and carrier transport performance: The cyano group can enhance intermolecular interactions, improve film formation, and optimize electron transport capabilities, making it suitable for the performance requirements of devices such as electromechanical light-emitting diodes (OLEDs); When the fixed position is tert-butyl, it inhibits molecular aggregation and reduces quenching: The tert-butyl group has a large steric hindrance, which can effectively hinder the π-π stacking interaction between molecules, avoid the formation of aggregated states that lead to fluorescence quenching, and improve the material's performance in solid or... Luminescence efficiency in concentrated solutions, improved material stability and processing performance: The hydrophobic properties and steric protection of tert-butyl groups can enhance the thermal and chemical stability of molecules; at the same time, it improves the solubility of materials in organic solvents, which facilitates film formation processes in device fabrication. Fine-tuning of luminescence performance: Compared with strong electron-withdrawing / donating groups, tert-butyl groups are weak electron-effect groups. Their introduction will not significantly change the HOMO-LUMO energy level difference of molecules. Device performance can be optimized while basically maintaining the original luminescence color, and the driving voltage is significantly reduced, resulting in a significant improvement in luminescence efficiency and lifetime.

[0046] 2. Compared with the organic electroluminescent devices prepared using the compounds provided in this application as doping materials for the luminescent layer, the organic electroluminescent devices prepared using the compounds provided in this application as doping materials for the luminescent layer have significantly lower driving voltages and significantly enhanced luminous efficiency.

[0047] The applicant declares that the technical solution of this invention is illustrated through the above embodiments, but this invention is not limited to the above embodiments, that is, it does not mean that this invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of the raw materials used in this invention, additions of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of this invention.

Claims

1. An organic electroluminescent material, characterized in that, The organic electroluminescent material has the structure shown in general formula I: ； R1, R2 and R4 are independently selected from any one or a combination of at least two of -H, -D, -F, -CD3, -CN, adamantane, C1-C10 alkyl groups wholly or partially substituted with deuterium, substituted or unsubstituted C6-C18 aryl groups, substituted or unsubstituted C6-C18 heteroaryl groups, substituted or unsubstituted C3-C10 cycloalkyl groups, -Si(Me)3, and -Ge(Me)3. R1, R2, R3, and R4 exist independently or are fused together or with each other at any position in the ring, or form cyclic groups together or with the ring. When substituted independently, R3 is selected from tert-butyl; R5, R7, R8, R9 and R 10 Each is independently selected from any one or a combination of at least two of the following: halogen, silanyl, silyl, adamantyl, carbazole, quinolinyl, methoxy, triazine, dibenzothiophene, benzothiophene, dibenzofuran, diphenylamino, -H, -D, -CD3, -CF3, -CN, -NO2, C1-C10 alkyl, C3-C10 cycloalkyl, C6-C18 aryl, C6-C18 heteroaryl, -Si(Me)3, -Ge(Me)3, and 4- to 18-membered heterocyclic groups; R5, R7, R8, R9 and R 10 They can exist independently or be fused together with each other or with any position in the ring, or form cyclic groups with each other or with the ring. When used as an independent substitution, R6 is selected from -CN; R5, R6, R7, R8, R9 and R 10 When cyclization occurs, the resulting rings are: benzene ring, naphthyl ring, pyridine ring, 1,1-dimethyl-2,3-dihydro-1-benzosilyl pentene ring, 1,1-dimethyl-2,3-dihydro-1-benzogermanium pentene ring, 2,3-dihydrobenzofuran ring, 2,3-dihydrobenzothiophene ring, quinoline ring, 9,10-dihydrophenanthrene ring, cyclohexane, and biphenyl ring; The above groups are either unsubstituted or substituted; The substitution refers to substitution by a substituent selected from one or at least two of the following substituents or at least two substituents linked together: -D, -F, -CD3, -CF3, methyl, ethyl, propyl, butyl, pentyl, hexyl, cyclopropyl, cyclobutyl, cyclopentyl, dimethylcyclopentyl, cyclohexyl, silyl, germanyl, 1,1-dimethylindanyl; W is independently selected from SiR'R''; wherein R' and R'' are selected from halogens, -CN, -D, substituted or unsubstituted C1-C10 alkyl, substituted or unsubstituted C6-C18 aryl, substituted or unsubstituted C3-C10 cycloalkyl, quinolinyl, and benzothiophene. R 11 R 12 R 13 R 14 R 15 R 16 R 17 and R 18 Independently selected from -H, -D, -CD3, -CN, -CF3, -NO2, -Si(Me)3, -Ge(Me)3, halogen, benzodimethylsilyl, benzodimethylgermanyl, methoxy, adamantyl, nitro, 1,1-dimethyl-2,3-dihydro-1H-indene-substituted naphthyl, cyano and phenyl-substituted naphthyl, dimethylcyclohexyl, siloxane, fluorenyl, phenanthrene, anthracene, indene, triphenylene, triazine, pyrene, tetraphenyl, perylene, trefyl, condensed tetraphenyl The following are all groups of phenyl, fluoranthryl, furanyl, thiophene, pyridyl, pyrimidinyl, benzofuranyl, benzothiophene, isobenzofuranyl, dibenzofuranyl, dibenzothiophene, quinolinyl, isoquinolinyl, quinazolinyl, carbazole, phenanthridine, benzom-dioxacyclopentenyl, C1-C10 alkyl, C3-C10 cycloalkyl, C3-C10 heterocyclic, substituted or unsubstituted C6-C18 aryl, substituted or unsubstituted C6-C18 heteroaryl; R 11 R 12 R 13 R 14 R 15 R 16 R 17 and R 18 They can exist independently or fuse with each other or at any position in the ring and can form cyclic groups with each other or with the ring. The substitution in the substituted or unsubstituted form refers to substitution by a substituent selected from one or at least two of the following groups, or at least two substituents linked together: -D, -F, -CD3, -CF3, methyl, ethyl, propyl, butyl, pentyl, hexyl, cyclopropyl, cyclobutyl, cyclopentyl, dimethylcyclopentyl, cyclohexyl, silyl, germanyl, 1,1-dimethylindanyl.

2. The organic electroluminescent material according to claim 1, characterized in that, R1, R2, and R4 are independently selected from any one or at least two combinations of methyl, ethyl, propyl, butyl, pentyl, phenyl, -H, -CN, -D, -F, -CD3, -Si(Me)3, -Ge(Me)3, adamantane, phenyl, cyclopropyl, cyclobutyl, and cyclopentyl; R1, R2, and R4 exist independently or are fused with each other or at any position on the ring, or form cyclic groups with each other or the ring. When substituted independently, R3 is selected from tert-butyl; R5, R7, R8, R9 and R 10 Each of the following is independently selected from any one or a combination of at least two of the following: -H, -D, -CD3, -CF3, -CN, -NO2, -CN, -F, -Si(Me)3, -Ge(Me)3, methyl, ethyl, propyl, butyl, pentyl, phenyl, cyclopropyl, cyclobutyl, cyclopentyl, biphenyl, silanyl, siloxane, adamantyl, carbazolyl, quinolinyl, naphthyl, methoxy, triazine, dibenzothiophene, benzothiophene, dibenzofuranyl, diphenylamino, and benzo-m-dioxacyclopentenyl. When used as an independent substitution, R6 is selected from -CN. R5, R6, R7, R8, R9 and R 10 When cyclization occurs, the resulting rings are: benzene ring, naphthyl ring, pyridine ring, 1,1-dimethyl-2,3-dihydro-1-benzosilyl pentene ring, 1,1-dimethyl-2,3-dihydro-1-benzogermanium pentene ring, 2,3-dihydrobenzofuran ring, 2,3-dihydrobenzothiophene ring, quinoline ring, 9,10-dihydrophenanthrene ring, cyclohexane, and biphenyl ring; R 11 R 12 R 13 R 14 R 15 R 16 R 17 and R 18 Independently selected from any one or at least two combinations of methyl, ethyl, propyl, butyl, pentyl, phenyl, methoxy, -H, -D, -F, -CD3, -NO2, -CN, -Si(Me)3, -Ge(Me)3, -CF3, benzodimethylsilyl, benzodimethylgermanium, adamantyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, quinolinyl, carbazole, 1,1-dimethyl-2,3-dihydro-1H-indenyl-substituted carbazole, naphthyl, thiophene, triazine, benzothiophene, furanyl, benzofuranyl, biphenyl, isobenzofuranyl, dibenzofuranyl, dibenzothiophene, isoquinolinyl, quinazolinyl, cyano and phenyl-substituted naphthyl, dimethylcyclohexyl, siloxane, R 11 R 12 R 13 R 14 R 15 R 16 R 17 and R 18 Two groups, either existing independently or adjacent to each other, can fuse together to form a cyclic structure; W is independently selected from SiR'R''; wherein R' and R'' are selected from -F, -D, -CN, methyl, phenyl, cyclopropyl, cyclopentyl, biphenyl, naphthyl, quinolinyl, or benzothiophene.

3. The organic electroluminescent material according to claim 1, characterized in that, ligands Choose from any of the following structures: ； The dashed lines represent the ligand attachment sites.

4. The organic electroluminescent material according to claim 1, characterized in that, ligands Choose from any of the following structures: ； The dashed lines represent the ligand attachment sites.

5. An organic electroluminescent device, characterized in that, The organic electroluminescent device includes an anode, a cathode, and an organic material layer disposed between the anode and the cathode, wherein the organic material layer includes at least one of the organic electroluminescent materials according to any one of claims 1-4.

6. The organic electroluminescent device according to claim 5, characterized in that, The organic material layer includes a light-emitting layer, which comprises a host material and a dopant material, wherein the dopant material comprises at least one of the organic electroluminescent materials according to any one of claims 1-4.

7. The organic electroluminescent device according to claim 6, characterized in that, The organic material layer further includes at least one of a hole injection layer, a hole transport layer, an electron blocking layer, an electron transport layer, or an electron injection layer.

8. The organic electroluminescent device according to claim 6, characterized in that, The organic electroluminescent device comprises an anode, a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, an electron transport layer, an electron injection layer, and a cathode arranged sequentially.

Images