An organic electroluminescent material, an organic electroluminescent device, and an organic electroluminescent apparatus

Abstract

The application discloses an organic electroluminescent material, an organic electroluminescent device and an organic electroluminescent apparatus, and relates to the technical field of organic electroluminescent materials.The compound of formula I is used as a mother nucleus, and is connected with an arylamine group;one of side chains of the arylamine group contains a 1,1,4,4-tetramethyl-1,2,3,4-tetrahydronaphthalene derivative;and the other side chain of the arylamine group is one of an aryl group or a heteroaryl group.The compound of formula I has a low refractive index, is applied to a thicker layer in a double-layer light-emitting auxiliary material, and makes the organic electroluminescent device prepared by matching the light emitted from the device with the low-refractive-film layer of formula I and the high-refractive light-emitting auxiliary material better play a light collecting role;the light emitted from the device can emit specific wavelength light, the emission spectrum can be narrowed, the light-emitting intensity of the specific wavelength light can be enhanced, light loss can be reduced, the light-emitting efficiency of the device can be improved, meanwhile, the device has a relatively low driving voltage and a relatively long service life.

Description

Technical Field

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

[0002] Organic electroluminescence (OLED) refers to the physical process by which organic functional materials convert electrical energy into light energy under the influence of an electric field. OLED devices, with their outstanding advantages such as self-emission, high contrast, wide viewing angle, and fast response, have been widely used in smartphones, display panels, televisions, and lighting. A typical OLED device mainly consists of an anode, a cathode, and an organic functional layer sandwiched between the two electrodes. To improve the luminous efficiency and lifespan of the device, the industry typically adds a light-emitting auxiliary layer between the hole transport layer and the light-emitting layer, forming a multi-layer hole transport structure.

[0003] The core function of the light-emitting auxiliary layer is to facilitate the smooth injection and transport of holes generated by the anode to the light-emitting layer, while effectively blocking electrons injected by the cathode, confining them within the light-emitting layer. This structure can reduce the energy level barrier between the hole transport layer and the light-emitting layer, reduce the device driving voltage, improve hole utilization, and ultimately achieve simultaneous improvement in device luminous efficiency and operating lifetime.

[0004] However, there is still a shortage of organic materials that can be used to prepare light-emitting auxiliary layers and significantly improve the overall performance of devices, especially in terms of limited effectiveness in improving OLED efficiency and lifetime. The final performance of a device is influenced by multiple factors, including device structure design, material refractive index, HOMO / LUMO energy levels, triplet energy, evaporation morphology, carrier mobility, carrier balance, evaporation temperature, and testing environment. Therefore, material performance often requires extensive experimental tuning and molecular structure modification to achieve ideal levels. Materials companies typically improve the overall performance of OLED devices by optimizing certain key indicators.

[0005] Faced with the current shortage of high-efficiency materials for light-emitting auxiliary layers and the continuous improvement of panel manufacturers' requirements for material performance, developing new organic functional materials that combine high stability and high efficiency has become an important issue that urgently needs to be addressed in the OLED field. Summary of the Invention

[0006] In view of this, the present invention provides an organic electroluminescent material, an organic electroluminescent device, and an organic electroluminescent apparatus. The compound of the present invention is of formula I. The parent nucleus is (arylalkylfluorene) and is linked to an aromatic amino group. One of the aromatic amino side chains contains a 1,1,4,4-tetramethyl-1,2,3,4-tetrahydronaphthalene derivative, and the other aromatic amino side chain is either aryl or heteroaryl. The resulting compound of formula I has a low refractive index.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] An organic electroluminescent material having the structure shown in Formula I: ; R1 is selected from substituted or unsubstituted C1-C. 15 alkyl; R2 is selected from substituted or unsubstituted C6-C. 15 Aryl; R3 is selected from substituted or unsubstituted C1-C. 15 Alkyl, substituted or unsubstituted C6-C 30 Aryl, substituted or unsubstituted C6-C 30 Heteroaryl groups, wherein the heteroatoms are one or more selected from O, S, N, Si, Ge, and P; R4 and R5 are each independently selected from hydrogen, substituted or unsubstituted C1-C. 15 Alkyl, substituted or unsubstituted C6-C 30 Aryl, substituted or unsubstituted C6-C 30 Heteroaryl groups, wherein the heteroatoms are one or more selected from O, S, N, Si, Ge, and P; Ar is selected from the following substituent groups;

[0009] Indicates the location where the group is attached.

[0010] Preferably, R1 is selected from substituted or unsubstituted C1-C6 alkyl groups; R2 is selected from substituted or unsubstituted phenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted biphenyl, or substituted or unsubstituted 1,1,4,4-tetramethyl-1,2,3,4-tetrahydronaphthalene. R3 is selected from substituted or unsubstituted C1-C6 alkyl groups, substituted or unsubstituted C6-C6 alkyl groups. 15 Aryl, substituted or unsubstituted C6-C 15 Heteroaryl groups, wherein the heteroatoms are one or more of O, S, N, Si, and Ge; R4 and R5 are each independently selected from hydrogen, substituted or unsubstituted C1-C6 alkyl groups, substituted or unsubstituted C6-C6 alkyl groups. 15 Aryl, substituted or unsubstituted C6-C 15 Heteroaryl groups, wherein the heteroatoms are one or more of O, S, N, Si, and Ge.

[0011] Preferably, the organic electroluminescent material has any one of the structures of formula I-1 to I-6: ; Wherein, R1 is selected from substituted or unsubstituted methyl, substituted or unsubstituted ethyl, or substituted or unsubstituted tert-butyl; R3 is selected from substituted or unsubstituted methyl, substituted or unsubstituted ethyl, substituted or unsubstituted tert-butyl, substituted or unsubstituted phenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted biphenyl, substituted or unsubstituted dibenzofuranyl, substituted or unsubstituted dibenzothiopheneyl, substituted or unsubstituted 9,9-dimethylfluorenyl. R2, R4, R5, and Ar are defined in the same way as general formula I; Furthermore, the hydrogen atoms in the aforementioned groups can be independently substituted with or not substituted with deuterium.

[0012] In this invention, the term "substituted or unsubstituted C6-C" is used. 30 "Aryl", "substituted or unsubstituted C6-C" 30 "Heteroaryl", "substituted or unsubstituted C1-C6 alkyl", "substituted or unsubstituted C6-C6 alkyl" 15 "Aryl", "substituted or unsubstituted C6-C" 15 The number of carbon atoms in "heteroaryl" refers to the number of carbon atoms constituting the unsubstituted aryl or unsubstituted alkyl group, or the total number of heteroatoms and carbon atoms constituting the heteroaryl group, without considering the number of carbon atoms in the substituents.

[0013] The term "substitution" means substitution by one, two or more substituents selected from the following: hydrogen, deuterium, halogen, cyano, trifluoromethyl, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, sec-butyl, 1-methylbutyl, 1-ethylbutyl, n-pentyl, isopentyl, neopentyl, tert-pentyl, n-hexyl, 1-methylpentyl, 2-methylpentyl, 4-methyl-2-pentyl, 3,3-dimethylbutyl, 2-ethylbutyl, 1-methylhexyl, phenyl, naphthyl, anthracene, phenanthrene, thiophene, furanyl, pyrrole, benzothiophene, benzofuranyl, pyridyl, indolyl, cyclopentyl, cyclohexyl, adamantane, or substitution by two or more substituents linked together from the substituents listed above, or no substituents.

[0014] Preferably, the organic electroluminescent material comprises any one of the following compounds:

[0015]

[0016]

[0017]

[0018]

[0019]

[0020]

[0021]

[0022]

[0023]

[0024]

[0025]

[0026]

[0027]

[0028] .

[0029] Another object of the present invention is to provide a method for preparing the above-mentioned organic electroluminescent material, the synthetic route of which is as follows: ; Hal1, Hal2, and Hal3 are each independently selected from fluorine, chlorine, bromine, or iodine; R1-R5 and Ar are defined in the same way as general formula I; The specific preparation method is as follows: (1) Under nitrogen protection, raw material A and raw material B were dissolved in toluene solution, sodium tert-butoxide, tris(dibenzylacetone)dipalladium, and tri-tert-butylphosphine were added, stirred evenly, heated to 90-110℃, and refluxed for 4-6 hours. After the reaction was completed, the temperature was lowered slightly, and the solution was filtered with diatomaceous earth to remove salt and catalyst. After the filtrate was cooled to room temperature, it was washed three times with water, and the organic phase was retained. Then the aqueous phase was extracted with ethyl acetate. After the organic phases were combined, the solution was dried with anhydrous magnesium sulfate, and the solvent was removed by a rotary evaporator. The solution was then dissolved in petroleum ether / ethanol, recrystallized, filtered, and the filter cake was rinsed with petroleum ether several times. The solution was then placed in a 60℃ oven and dried for 5 hours to obtain intermediate 1. (2) Under nitrogen atmosphere, raw material C and raw material D were added to a mixed solution of toluene, ethanol and water. Potassium carbonate and tetra(triphenylphosphine)palladium were added to the solution, stirred evenly, heated to 70℃-90℃ and refluxed for 4-12h. The reaction was detected by thin layer chromatography. After the reaction was completed, the temperature was lowered slightly and filtered with diatomaceous earth to remove salt and catalyst. After the filtrate was cooled to room temperature, it was washed three times with water and the organic phase was retained. Then the aqueous phase was extracted with dichloromethane. The organic phases were combined and concentrated. The intermediate 2 was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether as the eluent. (3) Under nitrogen atmosphere, raw material E and intermediate 2 were added to a mixed solution of toluene, ethanol and water. Potassium carbonate and tetra(triphenylphosphine)palladium were added to the solution. The mixture was stirred until homogeneous, heated to 70℃-90℃ and refluxed for 4-12 hours. The reaction was detected by thin-layer chromatography. After the reaction was completed, the temperature was lowered slightly and the solution was filtered with diatomaceous earth to remove salt and catalyst. The filtrate was cooled to room temperature and washed three times with water. The organic phase was retained and then the aqueous phase was extracted with dichloromethane. The organic phases were combined and concentrated. The intermediate 3 was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether as the eluent. (4) Under nitrogen protection, intermediates 3 and 1 were dissolved in toluene solution, sodium tert-butoxide, tris(dibenzylacetone)dipalladium, and tri-tert-butylphosphine were added, stirred evenly, heated to 90-110℃, and refluxed for 4-6 h. After the reaction was completed, the temperature was lowered slightly, and the mixture was filtered with diatomaceous earth to remove salt and catalyst. After the filtrate was cooled to room temperature, it was washed three times with water, and the organic phase was retained. The aqueous phase was then extracted with ethyl acetate. After the organic phases were combined, the mixture was dried with anhydrous magnesium sulfate, and the solvent was removed using a rotary evaporator. The mixture was then dissolved in petroleum ether / ethanol, recrystallized, filtered, and the filter cake was rinsed several times with petroleum ether and dried in a 60℃ oven for 5 h to obtain compound I.

[0030] The series of palladium-catalyzed coupling reactions in this invention utilize the activity differences of halogens I>Br>Cl, and control the reaction sites by controlling the reaction conditions. The reactions are purified by column chromatography or silica gel funnel to remove byproducts and obtain the target compound.

[0031] For raw materials that are not publicly available, those skilled in the art can synthesize them using classic Suzuki coupling reactions, Buchwald–Hartwig coupling reactions, butyllithium reactions, and apply them to this invention.

[0032] Another object of the present invention is to provide an organic electroluminescent device, the organic electroluminescent device comprising an anode, a cathode and an organic layer disposed between the anode and the cathode, the organic layer comprising a light-emitting auxiliary layer comprising the aforementioned organic electroluminescent material.

[0033] Preferably, the organic electroluminescent device further includes at least one of 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 structure of the organic light-emitting element is not limited to this, and may include fewer or more organic layers.

[0034] Preferably, the light-emitting auxiliary layer comprises multiple light-emitting auxiliary layers.

[0035] Preferably, the organic layer includes a hole transport layer and a light-emitting auxiliary layer. The light-emitting auxiliary layer includes a first light-emitting auxiliary layer and a second light-emitting auxiliary layer. The first light-emitting auxiliary layer includes the aforementioned organic electroluminescent material and is located between the hole transport layer and the second light-emitting auxiliary layer.

[0036] Preferably, the second luminescent auxiliary layer is selected from compounds having the general formula II structure in application document 202610299445.7:

[0037] Wherein, R is selected from hydrogen, deuterium, substituted or unsubstituted phenyl, substituted or unsubstituted C1-C6 alkyl; R1-R4 are each independently selected from hydrogen, deuterium, substituted or unsubstituted phenyl groups; R5 is selected from substituted or unsubstituted C1-C6 alkyl groups; When substituted, the substituent is deuterium, and the number of substituents is the number of positions that can be substituted to the maximum number of positions.

[0038] Preferably, general formula II has the structure shown in formula ac: ; Wherein, the substituted or unsubstituted C1-C6 alkyl group described in R and R5 is selected from one or more of methyl, ethyl, propyl, butyl, cyclopentyl, cyclohexyl, -CD3, -CHD2, and -DH2D; More preferably, the second light-emitting auxiliary layer has a specific structure of one or more of the following compounds:

[0039]

[0040]

[0041]

[0042]

[0043]

[0044]

[0045]

[0046]

[0047]

[0048]

[0049] .

[0050] Preferably, when manufacturing organic electroluminescent devices using the aforementioned organic electroluminescent materials, the organic layer is formed using vacuum evaporation or solution coating. Solution coating methods include spin coating, dip coating, blade coating, inkjet printing, screen printing, spray coating, and roll coating, but are not limited to these.

[0051] Depending on the materials used, the organic electroluminescent devices of the present invention are classified into top-emitting type, bottom-emitting type, or bidirectional-emitting type.

[0052] Preferably, the organic electroluminescent device of the present invention is used in organic electroluminescent devices, including but not limited to flat panel displays, computer monitors, medical monitors, televisions, billboards, lamps for internal or external lighting and / or signals, head-up displays, fully transparent or partially transparent displays, flexible displays, laser printers, telephones, mobile phones, tablets, photo albums, personal digital assistants (PDAs), wearable devices, laptops, digital cameras, camcorders, viewfinders, microdisplays, 3D displays, virtual reality or augmented reality displays, vehicles, and video walls of multiple displays tiled together, theater or stadium screens, phototherapy devices, and signs.

[0053] As the anode material, a material with a high work function is selected to facilitate the injection of holes into the organic layer. Specific examples of anode materials that can be used in this invention include vanadium, chromium, copper, zinc, gold or their alloys; metal oxides such as zinc oxide, indium oxide, indium tin oxide (ITO), and indium zinc oxide (IZO); combinations of metals and oxides such as ZnO:Al or SnO2:Sb; and conductive polymers such as polypyrrole and polyaniline.

[0054] The hole injection layer is selected as a p-doped hole injection layer, which means a hole injection layer doped with p-doped agents. P-doped agents are materials that can impart p-type semiconductor characteristics. P-type semiconductor characteristics refer to the characteristics of injecting or transporting holes at the HOMO energy level, that is, the characteristics of materials with high hole conductivity.

[0055] Hole transport material is a material capable of receiving holes from the anode or hole injection layer and transporting the holes to the light-emitting layer, and the hole transport material is a material with high hole mobility. The hole transport material is selected from aryl amine derivatives, conductive polymers, and block copolymers that simultaneously contain conjugated and non-conjugated parts.

[0056] An auxiliary light-emitting layer (multilayer hole transport layer) is added between the hole transport layer and the light-emitting layer. The auxiliary light-emitting layer primarily assists the hole transport layer and is therefore sometimes referred to as a second hole transport layer. This layer allows holes transferred from the anode to smoothly move to the light-emitting layer and blocks electrons transferred from the cathode, confining them within the light-emitting layer. This reduces the potential barrier between the hole transport layer and the light-emitting layer, lowers the driving voltage of the organic light-emitting device, and further increases hole utilization, thereby improving the device's luminous efficiency and lifetime.

[0057] The luminescent material in the luminescent layer is a material that can receive holes and electrons from the hole transport layer and the electron transport layer respectively, and combine them to emit light in the visible light region. The material with high quantum efficiency for fluorescence or phosphorescence is selected.

[0058] The light-emitting layer comprises a host material and a dopant material, with a mass ratio of host material to dopant material of 90-99.5:0.5-10.

[0059] The main materials are aromatic fused-ring derivatives or heterocyclic compounds. Specifically, aromatic fused-ring derivatives include anthracene derivatives, pyrene derivatives, naphthalene derivatives, pentane derivatives, phenanthrene compounds, or fluoranthene compounds, while heterocyclic compounds include carbazole derivatives, dibenzofuran derivatives, or pyrimidine derivatives.

[0060] The dopant materials of this invention include fluorescent doping and phosphorescent doping, specifically selected from aromatic amine derivatives, styrylamine compounds, boron complexes, fluoranthene compounds, or metal complexes.

[0061] The electron transport layer can promote electron transport. The electron transport material is a material that can effectively receive electrons from the cathode and transport them to the light-emitting layer. Specifically, it is selected from materials with high electron mobility. The electron transport layer includes an electron buffer layer, a hole blocking layer, and an electron transport layer.

[0062] The electron injection layer facilitates electron injection and has the ability to transport electrons, preventing excitons generated in the light-emitting layer from migrating to the hole injection layer. Materials for the electron injection layer include, but are not limited to, oxazoles, oxadiazoles, triazoles, imidazoles, perylenetetracarboxylic acids, fluorenemethane, anthrones and their derivatives, magnesium, calcium, sodium, potassium, titanium, indium, yttrium, lithium, gadolinium, aluminum, silver, tin, ytterbium, or their alloys, metal complexes, or nitrogen-containing 5-membered ring derivatives.

[0063] The cathode is selected from materials with a small work function to facilitate electron injection into an organic material layer with a thickness between 0.5 and 5 nm. Specifically, the cathode materials include magnesium, calcium, sodium, potassium, titanium, indium, yttrium, lithium, gadolinium, aluminum, silver, tin, and lead or their alloys: LiF / Al or LiO2 / Al, Mg / Ag multilayer structures.

[0064] Apart from Formula I included in the light-emitting auxiliary layer disclosed in this invention, there are no special restrictions on the materials of other layers in OLED devices. Existing hole injection materials, hole transport materials, hole transport auxiliary materials, dopant materials, hole blocking layer materials, electron transport layer materials, and electron injection materials can be used.

[0065] As can be seen from the above technical solution, compared with the prior art, the present invention has the following beneficial effects: Compound I of the present invention The parent nucleus is (arylalkylfluorene) and is linked to an aromatic amino group. One of the aromatic amino side chains contains a 1,1,4,4-tetramethyl-1,2,3,4-tetrahydronaphthalene derivative, and the other aromatic amino side chain is either aryl or heteroaryl. The resulting compound of formula I has a low refractive index.

[0066] The compound of Formula I of this invention, as a light-emitting auxiliary material, is applied to the thicker layer of a double-layer light-emitting auxiliary material. This allows the light emitted from the device to pass through the low-refractive-index film of Formula I. The organic electroluminescent device prepared by combining the low-refractive-index film of Formula I with the high-refractive-index light-emitting auxiliary material can better concentrate light, emit light of a specific wavelength from the light emitted from the device, narrow the emission spectrum, enhance the luminous intensity of the specific wavelength, reduce light loss, improve the luminous efficiency of the device, and at the same time ensure a low driving voltage and a long device life. Attached Figure Description

[0067] 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 only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0068] Figure 1 The image shows the proton NMR spectrum of compound 309.

[0069] Figure 2 The image shows the proton NMR spectrum of compound 311.

[0070] Figure 3 The image shows the proton NMR spectrum of compound 324.

[0071] Figure 4 The image shows the 1H NMR spectrum of compound 337. Detailed Implementation

[0072] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0073] It should be noted that the values ​​given in the following embodiments are as accurate as possible. However, those skilled in the art will understand that due to unavoidable measurement errors and experimental operation issues, each number should be understood as an approximation rather than an absolutely accurate value.

[0074] The following are common knowledge references: Organometallic Chemistry (6th Edition), Robert H. Crabtree, published by East China University of Science and Technology Press, Shanghai, September 00, 2017, ISBN: 978-7-5628-5111-0, page 388.

[0075] Organic Chemistry and Optoelectronic Materials Experiment Tutorial, Chen Runfeng, Publisher: Southeast University Press, Publication Date: 2019-11-00, ISBN: 9787564184230, Page 174.

[0076] The features and performance of the present invention will be further described in detail below with reference to specific embodiments.

[0077] Example 1: Synthesis of Compound 309

[0078] CAS: A-309: 1548450-59-4; CAS: B-309: 92050-16-3; CAS: C-309: 184885-74-3; CAS: D-309: 98-80-6.

[0079] Step 1: Under nitrogen protection, raw materials A-309 (1.3 eq) and B-309 (1.0 eq) were dissolved in toluene solution, and sodium tert-butoxide (2.00 eq), tris(dibenzylacetone)dipalladium (0.01 eq), and tri-tert-butylphosphine (0.05 eq) were added. The mixture was stirred until homogeneous, heated to 100 °C, and refluxed for 6 h. After the reaction was completed, the temperature was slightly lowered, and the mixture was filtered with diatomaceous earth to remove salts and catalysts. The filtrate was cooled to room temperature, washed three times with water, and the organic phase was retained. The aqueous phase was then extracted with ethyl acetate. The combined organic phases were dried with anhydrous magnesium sulfate, and the solvent was removed using a rotary evaporator. The mixture was then dissolved in petroleum ether / ethanol, recrystallized, filtered, and the filter cake was washed multiple times with petroleum ether and dried in a 60 °C oven for 5 h to obtain intermediate 1, with a yield of 88.43%.

[0080] Step 2: Under nitrogen atmosphere, raw materials C-309 (1.0 eq) and D-309 (1.0 eq) were added to a mixed solution of toluene, ethanol, and water. Potassium carbonate (2.2 eq) and tetrakis(triphenylphosphine)palladium (0.01 eq) were added, and the mixture was stirred until homogeneous. The mixture was heated to 90 °C and refluxed for 10 h. The reaction was detected by thin-layer chromatography. After the reaction was completed, the temperature was slightly lowered, and the mixture was filtered with diatomaceous earth to remove salts and catalysts. The filtrate was cooled to room temperature and washed three times with water, retaining the organic phase. The aqueous phase was then extracted with dichloromethane. The organic phases were combined and concentrated. The intermediate 2 was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether as the eluent, with a yield of 43.24%.

[0081] Step 3: Under nitrogen protection, intermediates 1 (1 eq) and 2 (1.3 eq) were dissolved in toluene solution, and sodium tert-butoxide (2.00 eq), tris(dibenzylacetone)dipalladium (0.01 eq), and tri-tert-butylphosphine (0.05 eq) were added. The mixture was stirred until homogeneous, heated to 110 °C, and refluxed for 6 h. After the reaction was completed, the temperature was slightly lowered, and the mixture was filtered with diatomaceous earth to remove salts and catalysts. The filtrate was cooled to room temperature, washed three times with water, and the organic phase was retained. The aqueous phase was then extracted with ethyl acetate. The combined organic phases were dried with anhydrous magnesium sulfate, and the solvent was removed using a rotary evaporator. The mixture was then dissolved in petroleum ether / ethanol, recrystallized, filtered, and the filter cake was washed multiple times with petroleum ether and dried in a 60 °C oven for 5 h to obtain compound 309, with a yield of 86.55%.

[0082] Characterization: The proton NMR spectrum of compound 309 is as follows: Figure 1 As shown.

[0083] HPLC purity: >99.8%.

[0084] Test value ((ESI, m / Z): [M+H]+): 719.57; Elemental analysis: Test values: C, 90.03; H, 8.04; N, 2.03.

[0085] Example 2: Synthesis of Compound 311

[0086] CAS: A-311: 1548450-59-4; CAS: B-311: 769-92-6; CAS: C-311: 184885-74-3; CAS: D-311: 98-80-6.

[0087] Step 1: Under nitrogen protection, raw materials A-311 (1.3 eq) and B-311 (1.0 eq) were dissolved in toluene solution, and sodium tert-butoxide (2.00 eq), tris(dibenzylacetone)dipalladium (0.01 eq), and tri-tert-butylphosphine (0.05 eq) were added. The mixture was stirred until homogeneous, heated to 100 °C, and refluxed for 6 h. After the reaction was completed, the temperature was slightly lowered, and the mixture was filtered with diatomaceous earth to remove salts and catalysts. The filtrate was cooled to room temperature, washed three times with water, and the organic phase was retained. The aqueous phase was then extracted with ethyl acetate. The combined organic phases were dried with anhydrous magnesium sulfate, and the solvent was removed using a rotary evaporator. The mixture was then dissolved in petroleum ether / ethanol for recrystallization. After filtration, the filter cake was washed multiple times with petroleum ether and dried in a 60 °C oven for 5 h to obtain intermediate 1, with a yield of 84.32%.

[0088] Step 2: Under nitrogen atmosphere, raw materials C-309 (1.0 eq) and D-309 (1.0 eq) were added to a mixed solution of toluene, ethanol, and water. Potassium carbonate (2.2 eq) and tetrakis(triphenylphosphine)palladium (0.01 eq) were added, and the mixture was stirred until homogeneous. The mixture was heated to 90 °C and refluxed for 10 h. The reaction was detected by thin-layer chromatography. After the reaction was completed, the temperature was slightly lowered, and the mixture was filtered with diatomaceous earth to remove salts and catalysts. The filtrate was cooled to room temperature and washed three times with water, retaining the organic phase. The aqueous phase was then extracted with dichloromethane. The organic phases were combined and concentrated. The intermediate 2 was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether as the eluent, with a yield of 43.24%.

[0089] Step 3: Under nitrogen protection, intermediates 1 (1 eq) and 2 (1.3 eq) were dissolved in toluene solution, and sodium tert-butoxide (2.00 eq), tris(dibenzylacetone)dipalladium (0.01 eq), and tri-tert-butylphosphine (0.05 eq) were added. The mixture was stirred until homogeneous, heated to 110 °C, and refluxed for 6 h. After the reaction was completed, the temperature was slightly lowered, and the mixture was filtered with diatomaceous earth to remove salts and catalysts. The filtrate was cooled to room temperature and washed three times with water, retaining the organic phase. The aqueous phase was then extracted with ethyl acetate. The combined organic phases were dried with anhydrous magnesium sulfate, and the solvent was removed using a rotary evaporator. The mixture was then dissolved in petroleum ether / ethanol for recrystallization. After filtration, the filter cake was washed multiple times with petroleum ether and dried in a 60 °C oven for 5 h to obtain compound 309, with a yield of 81.77%.

[0090] Characterization: HPLC purity: >99.8%.

[0091] Test value ((ESI, m / Z): [M+H]+): 665.53; Elemental analysis: Test values: C, 90.06; H, 7.84; N, 2.20.

[0092] Example 3: Synthesis of Compound 324 Since there is no existing technology for raw material A-324, the following synthetic route was adopted for synthesis:

[0093] CAS: a-324: 2142-69-0; CAS: b-324: 3900-89-8; CAS: c-324: 3972-65-4; Step 1: Under nitrogen atmosphere, raw materials a-324 (1.0 eq) and b-324 (1.0 eq) were added to a mixed solution of toluene, ethanol, and water. Potassium carbonate (2.2 eq) and tetrakis(triphenylphosphine)palladium (0.01 eq) were added, and the mixture was stirred until homogeneous. The mixture was heated to 90 °C and refluxed for 10 h. The reaction was detected by thin-layer chromatography. After the reaction was completed, the temperature was slightly lowered, and the mixture was filtered with diatomaceous earth to remove salts and catalysts. The filtrate was cooled to room temperature and washed three times with water, retaining the organic phase. The aqueous phase was then extracted with dichloromethane. The organic phases were combined and concentrated. The mixture was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether as the eluent to obtain 324-intermediate 1, with a yield of 81.45%.

[0094] Step 2: The raw material c-324 (1.0 eq) was dissolved in THF at -78℃, and the mixture was vented 3 times and stirred for 10 minutes. Then, n-butyllithium (1.2 eq) was slowly added to the c-324 solution. After reacting for 2 hours, the 324-intermediate 1 (1.0 eq) solution was slowly added to the reaction flask and stirred until homogeneous. The refrigeration was stopped, and the mixture was allowed to rise to room temperature and continue to react for 12 hours. The reaction was detected by thin-layer chromatography. After the reaction was completed, the mixture was washed three times with water, and the organic phase was retained. The aqueous phase was then extracted with dichloromethane. The organic phases were combined and concentrated. The 324-intermediate 2 was purified by column chromatography using a mixed solution of dichloromethane and petroleum as the eluent, with a yield of 65.91%.

[0095] Step 3: 324-Intermediate 2 (1.0 eq) was dissolved in DCM and stirred at room temperature. Then, boron trifluoride diethyl ether (5.0 eq) was added and stirred until homogeneous. The reaction was carried out at room temperature for 2 h. The reaction was detected by thin-layer chromatography. After the reaction was completed, the mixture was washed three times with water, and the organic phase was retained. The aqueous phase was then extracted with ethyl acetate. The organic phases were combined and dried with anhydrous magnesium sulfate, and the solvent was removed using a rotary evaporator. The solid organic matter was completely dissolved with a small amount of dichloromethane and then slowly added dropwise to a petroleum ether solution. The mixture was stirred until homogeneous, and a precipitate was formed. The precipitate was filtered to obtain a solid, which was washed successively with anhydrous ethanol and petroleum ether, and then dried to obtain raw material A-324, with a yield of 85.56%.

[0096]

[0097] CAS: B-324: 4106-66-5; CAS: C-324: 184885-74-3; CAS: D-324: 98-80-6.

[0098] Step 4: Under nitrogen protection, starting materials A-324 (1.3 eq) and B-311 (1.0 eq) were dissolved in toluene solution. Sodium tert-butoxide (2.00 eq), tris(dibenzylacetone)dipalladium (0.01 eq), and tri-tert-butylphosphine (0.05 eq) were added, and the mixture was stirred until homogeneous. The mixture was heated to 100 °C and refluxed for 6 h. After the reaction was complete, the temperature was slightly lowered, and the mixture was filtered through diatomaceous earth to remove salts and catalyst. The filtrate was cooled to room temperature, washed three times with water, and the organic phase was retained. The aqueous phase was then extracted with ethyl acetate. The combined organic phases were dried with anhydrous magnesium sulfate, and the solvent was removed using a rotary evaporator. The solution was then dissolved in petroleum ether / ethanol for recrystallization. After filtration, the filter cake was washed several times with petroleum ether and dried in a 60 °C oven for 5 h to obtain intermediate 1. Yield: 83.15% Step 5: Under nitrogen atmosphere, raw materials C-324 (1.0 eq) and D-324 (1.0 eq) were added to a mixed solution of toluene, ethanol, and water. Potassium carbonate (2.2 eq) and tetrakis(triphenylphosphine)palladium (0.01 eq) were added, and the mixture was stirred until homogeneous. The mixture was heated to 90°C and refluxed for 10 h. The reaction was detected by thin-layer chromatography. After the reaction was complete, the temperature was slightly lowered, and the mixture was filtered through diatomaceous earth to remove salts and catalysts. The filtrate was cooled to room temperature and washed three times with water, retaining the organic phase. The aqueous phase was then extracted with dichloromethane. The combined organic phases were concentrated, and the intermediate 2 was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether as the eluent. Yield: 43.24% Step 6: Under nitrogen protection, intermediates 1 (1 eq) and 2 (1.3 eq) were dissolved in toluene solution, and sodium tert-butoxide (2.00 eq), tris(dibenzylacetone)dipalladium (0.01 eq), and tri-tert-butylphosphine (0.05 eq) were added. The mixture was stirred until homogeneous, heated to 110 °C, and refluxed for 6 h. After the reaction was completed, the temperature was slightly lowered, and the mixture was filtered through diatomaceous earth to remove salts and catalysts. The filtrate was cooled to room temperature, washed three times with water, and the organic phase was retained. The aqueous phase was then extracted with ethyl acetate. The combined organic phases were dried with anhydrous magnesium sulfate, and the solvent was removed using a rotary evaporator. The mixture was then dissolved in petroleum ether / ethanol, recrystallized, filtered, and the filter cake was washed several times with petroleum ether and dried in a 60 °C oven for 5 h to obtain compound 324. Yield: 79.52% Characterization: HPLC purity: >99.8%.

[0099] Test value ((ESI, m / Z): [M+H]+): 755.52; Elemental analysis: Test values: C, 88.77; H, 7.19; N, 1.93; O, 2.21.

[0100] Example 4: Synthesis of Compound 337 Since there is no existing technology for the raw material A-337, the following synthetic route was adopted:

[0101] CAS: a-337: 2142-69-0; CAS: b-337: 3900-89-8; CAS: c-337:27452-17-1; Step 1: Under nitrogen atmosphere, raw materials a-337 (1.0 eq) and b-337 (1.0 eq) were added to a mixed solution of toluene, ethanol, and water. Potassium carbonate (2.2 eq) and tetrakis(triphenylphosphine)palladium (0.01 eq) were added, and the mixture was stirred until homogeneous. The mixture was heated to 90 °C and refluxed for 10 h. The reaction was detected by thin-layer chromatography. After the reaction was completed, the temperature was slightly lowered, and the mixture was filtered with diatomaceous earth to remove salts and catalysts. The filtrate was cooled to room temperature and washed three times with water, retaining the organic phase. The aqueous phase was then extracted with dichloromethane. The organic phases were combined and concentrated. The mixture was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether as the eluent to obtain 337-intermediate 1, with a yield of 81.45%.

[0102] Step 2: The raw material c-337 (1.0 eq) was dissolved in THF at -78℃, and the mixture was vented three times and stirred for 10 minutes. Then, n-butyllithium (1.2 eq) was slowly added to the c-337 solution. After reacting for 2 hours, the 337-intermediate 1 (1.0 eq) solution was slowly added to the reaction flask and stirred until homogeneous. The refrigeration was stopped, and the mixture was allowed to rise to room temperature. The reaction was continued for 12 hours. The reaction was detected by thin-layer chromatography. After the reaction was completed, the mixture was washed three times with water, and the organic phase was retained. The aqueous phase was then extracted with dichloromethane. The organic phases were combined and concentrated. The 337-intermediate 2 was purified by column chromatography using a mixed solution of dichloromethane and petroleum as the eluent, with a yield of 63.24%.

[0103] Step 3: 337-Intermediate 2 (1.0 eq) was dissolved in DCM and stirred at room temperature. Then, boron trifluoride diethyl ether (5.0 eq) was added and stirred until homogeneous. The reaction was carried out at room temperature for 2 h. The reaction was detected by thin-layer chromatography. After the reaction was completed, the mixture was washed three times with water, and the organic phase was retained. The aqueous phase was then extracted with ethyl acetate. The organic phases were combined and dried with anhydrous magnesium sulfate, and the solvent was removed using a rotary evaporator. The solid organic matter was completely dissolved with a small amount of dichloromethane and then slowly added dropwise to a petroleum ether solution. The mixture was stirred until homogeneous, and a precipitate was formed. The precipitate was filtered to obtain a solid, which was washed successively with anhydrous ethanol and petroleum ether, and then dried to obtain raw material A-337 with a yield of 81.13%.

[0104]

[0105] CAS: B-337: 62-53-3; CAS: C-337: 184885-74-3; CAS: D-337: 98-80-6.

[0106] Step 4: Under nitrogen protection, raw materials A-337 (1.3 eq) and B-337 (1.0 eq) were dissolved in toluene solution, and sodium tert-butoxide (2.00 eq), tris(dibenzylacetone)dipalladium (0.01 eq), and tri-tert-butylphosphine (0.05 eq) were added. The mixture was stirred until homogeneous, heated to 100 °C, and refluxed for 6 h. After the reaction was completed, the temperature was slightly lowered, and the mixture was filtered with diatomaceous earth to remove salts and catalysts. The filtrate was cooled to room temperature and washed three times with water, retaining the organic phase. The aqueous phase was then extracted with ethyl acetate. The combined organic phases were dried with anhydrous magnesium sulfate, and the solvent was removed using a rotary evaporator. The mixture was then dissolved in petroleum ether / ethanol for recrystallization. After filtration, the filter cake was washed multiple times with petroleum ether and dried in a 60 °C oven for 5 h to obtain intermediate 1, with a yield of 85.62%.

[0107] Step 5: Under nitrogen atmosphere, raw materials C-337 (1.0 eq) and D-337 (1.0 eq) were added to a mixed solution of toluene, ethanol, and water. Potassium carbonate (2.2 eq) and tetrakis(triphenylphosphine)palladium (0.01 eq) were then added, and the mixture was stirred until homogeneous. The mixture was heated to 90°C and refluxed for 10 h. The reaction was detected by thin-layer chromatography. After the reaction was complete, the temperature was slightly lowered, and the mixture was filtered through diatomaceous earth to remove salts and catalysts. The filtrate was cooled to room temperature and washed three times with water, retaining the organic phase. The aqueous phase was then extracted with dichloromethane. The combined organic phases were concentrated, and the intermediate 2 was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether as the eluent. Yield: 43.24%.

[0108] Step 6: Under nitrogen protection, intermediates 1 (1 eq) and 2 (1.3 eq) were dissolved in toluene solution, and sodium tert-butoxide (2.00 eq), tris(dibenzylacetone)dipalladium (0.01 eq), and tri-tert-butylphosphine (0.05 eq) were added. The mixture was stirred until homogeneous, heated to 110 °C, and refluxed for 6 h. After the reaction was completed, the temperature was slightly lowered, and the mixture was filtered through diatomaceous earth to remove salts and catalysts. The filtrate was cooled to room temperature, washed three times with water, and the organic phase was retained. The aqueous phase was then extracted with ethyl acetate. The combined organic phases were dried with anhydrous magnesium sulfate, and the solvent was removed using a rotary evaporator. The mixture was then dissolved in petroleum ether / ethanol, recrystallized, filtered, and the filter cake was washed several times with petroleum ether and dried in a 60 °C oven for 5 h to obtain compound 337. Yield: 76.33%.

[0109] Characterization: HPLC purity: >99.8%.

[0110] Test value ((ESI, m / Z): [M+H]+): 719.52; Elemental analysis: Test values: C, 90.01; H, 8.06; N, 2.04.

[0111] Additionally, it should be noted that other compounds in this application can be obtained by referring to the synthesis methods listed in the examples above, so they will not be listed one by one here. The mass spectrometer used for mass spectrometry in this application is a Waters XEVO TQD, which is low-precision and uses an ESI source.

[0112] Refractive index test Preparation of monolayer films for optical property evaluation Compound I (see the compounds of this invention in Table 1) and comparative compounds 1-12 were respectively deposited on silicon substrates with a film thickness of 40 nm. The refractive index n and extinction coefficient k at a wavelength of 530 nm were measured. The structures of comparative compounds 1-12 are shown below, and the measurement data are shown in Table 1.

[0113] Table 1. Test results of refractive index n and extinction coefficient k

[0114] Under a refractive index test at 530 nm, the refractive index of compound I of the present invention is between 1.61 and 1.68, while that of the comparative compound is between 1.72 and 1.78. Under similar structures, the refractive index is reduced by about 2.28% to 10.56%, and the extinction coefficient k value is almost 0 in each color gamut, which does not affect the luminescence of the luminescent layer.

[0115] Compound I of this invention uses an alkylarylfluorene derivative as its core, linked to an aromatic amino group. One of the aromatic amino side chains contains a 1,1,4,4-tetramethyl-1,2,3,4-tetrahydronaphthalene derivative, along with substituents Ar (especially phenyl, 1,1,4,4-tetramethyl-1,2,3,4-tetrahydronaphthalene, and tert-butylphenyl). The presence of numerous alkyl structures in the compound effectively increases the molecular volume, reducing the number of molecules per unit volume, thus lowering the overall density of the material. According to the Lorentz-Lorentz equation, the refractive index is positively correlated with the density of the material. The decrease in intermolecular density further contributes to a decrease in refractive index. Therefore, the resulting compound of formula I has a low refractive index.

[0116] The low-refractive-index compound of Formula I of this invention is used as a light-emitting auxiliary material in the thicker layer of a double-layer light-emitting auxiliary material. This allows the light emitted from the device to pass through the low-refractive-index film of Formula I. The organic electroluminescent device prepared by combining the low-refractive-index film of Formula I with the high-refractive-index light-emitting auxiliary material can better concentrate the light, emit specific wavelengths of light emitted from the device, narrow the emission spectrum, enhance the luminous intensity of specific wavelengths of light, reduce light loss, improve the luminous efficiency of the device, and at the same time ensure a low driving voltage and a long device life.

[0117] The following examples illustrate the application of the low refractive index material of Formula I provided in this application in organic electroluminescent devices.

[0118] Device Example 1 (Green Organic Electroluminescent Device): a. ITO anode: An ITO (indium tin oxide)-Ag-ITO (indium tin oxide) glass substrate with a coating thickness of 14nm / 150nm / 14nm is washed twice in distilled water, ultrasonically cleaned for 30 minutes, then washed twice more in distilled water, ultrasonically cleaned for 10 minutes. After washing, it is transferred to a spin dryer for spin drying, and finally baked in a vacuum oven at 220℃ for 2 hours. After baking, it is cooled down before use. Using this substrate as the anode, the device process is carried out using a vapor deposition machine, and other functional layers are sequentially vapor deposited on it.

[0119] b. HIL (hole injection layer): Hole injection layer materials HT-1 and P-dopant were vacuum-deposited at a deposition rate of 1 Å / s, with a deposition rate ratio of HT-1 to P-dopant of 95:5 and a thickness of 10 nm. c. HTL (hole transport layer): 130 nm of HT1 is vacuum-deposited on the hole injection layer at a deposition rate of 1.0 Å / s as a hole transport layer. d. Light-emitting auxiliary layer-1: Compound 309 of Formula I provided in this embodiment of the invention is vacuum-deposited on the hole transport layer at a deposition rate of 1.0 Å / s for 40 nm as light-emitting auxiliary layer-1. e. Light-emitting auxiliary layer-2: Prime2-131 with a 5 nm layer is vacuum-deposited on the light-emitting auxiliary layer-1 at a deposition rate of 1.0 Å / s as light-emitting auxiliary layer-2; f. EML (Emitting Layer): Then, on the above-mentioned emitting auxiliary layer, a host material (Host-1 and Host-2) and a dopant material (Dopant-G) with a thickness of 40 nm are vacuum-deposited at a deposition rate of 1 Å / s as the emitting layer. Host-1 and Host-2 are co-deposited with the dopant material as dual host materials, with a ratio of 50%:50%. The deposition rate ratio of the host material to the dopant is 90:10.

[0120] g. HBL (hole blocking layer): HB-1 with a thickness of 5.0 nm was vacuum-deposited at a deposition rate of 0.5 Å / s as a hole blocking layer.

[0121] h. ETL (Electron Transport Layer): ET-1 and Liq, with a thickness of 30 nm, were vacuum-deposited at a deposition rate of 1 Å / s as the electron transport layer. The deposition rate ratio of ET-1 to Liq was 50:50.

[0122] i. EIL (Electron Injection Layer): A 1.0 nm Yb film is deposited at a deposition rate of 0.5 Å / s to form an electron injection layer.

[0123] j. Cathode: Magnesium and silver are deposited at a deposition rate of 1 Å / s for 13 nm, with a deposition rate ratio of 1:9, to form the cathode.

[0124] k. Optical extraction layer: CPL-1 with a thickness of 60 nm is vacuum-deposited on the cathode at a deposition rate of 1 Å / s as the optical extraction layer.

[0125] The vapor-deposited substrate is then encapsulated. First, a UV adhesive is applied to the cleaned cover plate using a coating equipment. Then, the coated cover plate is moved to the lamination section, where the vapor-deposited substrate is placed on top of the cover plate. Finally, the substrate and cover plate are laminated together using a bonding equipment, while simultaneously curing the UV adhesive under UV light.

[0126] The structural formulas of the raw materials required for each of the above layers are shown below: .

[0127] Device Examples 2-90 Organic electroluminescent devices of Examples 2-90 were prepared according to the above-described method for preparing organic electroluminescent devices, except that compound 309 in Example 1 was replaced with compounds 1, 3, 4, 9, 13, 23, 24, 26, 29, 32, 33, 34, 38, 45, 47, 49, 50, 53, 58, 65, 69, 74, 78, 84, 92, 96, 101, 104, 113, 122, 123, 129, 133, 138, 141, 145, 151, 161, 168, 176, 180, and 1, respectively. Lines 83, 186, 187, 193, 201, 209, 212, 213, 215, 218, 225, 226, 232, 237, 240, 244, 250, 257, 261, 263, 267, 273, 277, 281, 288, 292, 300, 301, 305, 311, 314, 316, 317, 321, 324, 330, 337, 340, 342, 350, 355, 367, 374, 385, 388, 391, 402, and 411 form the luminescent auxiliary layer-1.

[0128] Device Examples 91-114 Organic electroluminescent devices of device examples 91-114 were prepared according to the above-described method for preparing organic electroluminescent devices, except that compound prime2-131 in device example 1 was replaced with compounds prime2-1, prime2-63, prime2-94, prime2-115, prime2-160, and prime2-245, respectively, to form a light-emitting auxiliary layer-2.

[0129] Device Comparison Examples 1-12 Organic electroluminescent devices of Comparative Examples 1-12 were prepared according to the preparation method of Organic Electroluminescent Device Application Example 1 above, except that compound 309 in Device Example 1 was replaced with the corresponding comparative compound (refer to the comparative compound al involved in Table 1) to form a light-emitting auxiliary layer.

[0130] The driving voltage, luminous efficiency, and lifetime of the organic electroluminescent devices obtained in Application Example 1 and Comparative Examples 1-12 were characterized at a brightness of 15000 nits. The test results are shown in Table 2 below.

[0131] Table 2. Results of luminous properties test (luminance value 15000 nits)

[0132] As shown in Table 2, changing the substituents and their positions alters the device performance, improving luminous efficiency and lifetime to varying degrees. The table also shows that, compared to existing organic electroluminescent devices provided in Comparative Examples 1-12, the OLED devices prepared using the luminescent auxiliary materials provided in the embodiments of this invention (Examples 1-90) exhibit a significant advantage in device lifetime, increasing it by 7.73-23.88% compared to the comparative examples. Furthermore, the luminescent auxiliary materials also show some improvement in device driving voltage and luminous efficiency, with driving voltage reduced by 2.44-13.76% and luminous efficiency increased by 2.34-12.65% compared to the comparative examples. The main difference between comparative compounds a and b and the compounds of the present invention lies in the different substituents on the aromatic amine. Comparative compound a and compounds 225-232 of the present invention are parallel comparative examples. The main difference between them is the different substituents on the aromatic amine. The aromatic amine substituents on the comparative compounds are naphthyl groups, while those on the compounds of the present invention are other groups. The naphthyl rings between the naphthyl groups are prone to tight π-π stacking, which can easily induce aggregation quenching (ACQ) and lead to a decrease in luminescence efficiency. However, the substituents selected in the compounds of the present invention can effectively extend the conjugated system, reduce the π-π stacking between molecules and the fluorescence quenching phenomenon caused by excessive molecular aggregation, and effectively improve luminescence efficiency and device lifetime.

[0133] The main difference between comparative compounds e- and l and the compounds of the present invention lies in whether the 1,1,4,4-tetramethyl-1,2,3,4-tetrahydronaphthalene attached to the side chain of the aromatic amine contains substituents. Comparative compounds e and 49 are parallel comparative examples, comparative compounds h and 23 are parallel comparative examples, comparative compounds j and 3 are parallel comparative examples, and comparative compounds i and 24 are parallel comparative examples. The 1,1,4,4-tetramethyl-1,2,3,4-tetrahydronaphthalene on the side chain of the aromatic amine in the comparative compounds does not contain substituents, while the 1,1,4,4-tetramethyl-1,2,3,4-tetrahydronaphthalene in the compounds of the present invention contains aryl, heteroaryl, or alkyl substituents. By connecting these groups, the conjugated system can be effectively extended, reducing the π-π stacking interaction between molecules and the fluorescence quenching phenomenon caused by excessive molecular aggregation, thereby effectively improving luminescence efficiency and device lifetime.

[0134] As can be seen from the above parallel comparative examples, the compound I of the present invention is based on... The compound uses an arylalkylfluorene core linked to an aromatic amine group. One of the aromatic amine side chains contains a 1,1,4,4-tetramethyl-1,2,3,4-tetrahydronaphthalene derivative, while the other side chain is either aryl or heteroaryl. This effectively extends the conjugated system, reduces intermolecular π-π stacking interactions and fluorescence quenching caused by excessive molecular aggregation, thus significantly improving luminous efficiency and device lifetime. The resulting compound also exhibits a low refractive index. As shown in Table 2, using the low-refractive-index compound of this invention as a luminescent auxiliary material, applied to the thicker layer of a bilayer luminescent auxiliary material, results in a green light device with a longer lifetime and better luminous efficiency.

[0135] The applicant declares that the organic electroluminescent materials and organic electroluminescent devices of the present invention are illustrated through the above embodiments, but the present invention is not limited to the above embodiments, that is, it does not mean that the present invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials used in the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

[0136] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An organic electroluminescent material, characterized in that, The organic electroluminescent material is any one of the following compounds: 。 2. An organic electroluminescent device, characterized in that, The organic electroluminescent device includes an anode, a cathode, and an organic layer disposed between the anode and the cathode. The organic layer includes a light-emitting auxiliary layer, which includes the organic electroluminescent material of claim 1.

3. An organic electroluminescent device according to claim 2, characterized in that, The organic electroluminescent device further includes at least one of 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.

4. An organic electroluminescent device according to claim 2, characterized in that, The organic layer includes a hole transport layer and a light-emitting auxiliary layer. The light-emitting auxiliary layer includes a first light-emitting auxiliary layer and a second light-emitting auxiliary layer. The first light-emitting auxiliary layer includes the organic electroluminescent material according to claim 1. The first light-emitting auxiliary layer is located between the hole transport layer and the second light-emitting auxiliary layer. The second light-emitting auxiliary layer is selected from compounds having the general formula II structure: Wherein, R is selected from hydrogen, deuterium, substituted or unsubstituted phenyl, substituted or unsubstituted C1-C6 alkyl; R1-R4 are each independently selected from hydrogen, deuterium, substituted or unsubstituted phenyl groups; R5 is selected from substituted or unsubstituted C1-C6 alkyl groups; When substituted, the substituent is deuterium, and the number of substituents is the number of positions that can be substituted to the maximum number of positions.

5. An organic electroluminescent device according to claim 4, characterized in that, The second light-emitting auxiliary layer is one or more of the following compounds: 。 6. An organic electroluminescent device, characterized in that, The organic electroluminescent device includes the organic electroluminescent device as described in claim 4 or 5.

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