Organic electroluminescent compound, organic electroluminescent material containing double-host material and luminescent device

Abstract

The invention provides an organic electroluminescent compound, an organic electroluminescent material containing a double-host material and a luminescent device.The organic electroluminescent compound has a structure as shown in a general formula 1, and the double-host material comprises a first host material and a second host material, the first main body material is the organic electroluminescent compound, the second main body compound has a structure as shown in a formula 2-1 or a formula 2-2, and when the organic electroluminescent material containing the double main body materials is applied to a luminescent layer material of an organic electroluminescent device, driving voltage can be reduced, the luminous efficiency of the organic electroluminescent device can be improved, and the luminous efficiency of the organic electroluminescent device can be improved. And the service life is prolonged.

Description

Technical Field

[0001] This invention belongs to the field of organic optoelectronic materials technology, and more specifically, relates to an organic electroluminescent compound, an organic electroluminescent material containing two host materials, and a light-emitting device. Background Technology

[0002] Organic electroluminescent devices are self-emissive devices that have attracted widespread attention in the panel display device industry due to their characteristics such as low driving voltage, high resolution, high brightness, fast response time, and flexibility.

[0003] Currently, organic light-emitting diode (OLED) display technology has been applied in fields such as smartphones and tablets, and will be expanded to large-size applications such as televisions. However, compared with the requirements of actual product applications, the performance of OLED, such as luminous efficiency and lifespan, still needs to be further improved.

[0004] The luminescent material of an organic light-emitting diode (OLED) device is the most important factor determining the device's luminous efficiency. Functionally, it can be divided into host materials and dopant materials. The luminescent material can be used by mixing host and dopant materials to improve color purity, luminous efficiency, and stability. Typically, devices with excellent electroluminescence (EL) characteristics have a luminescent layer structure formed by incorporating dopant materials into the host material. When using this dopant / host material system as the luminescent material, the host material significantly affects the efficiency and lifespan of the OLED device; therefore, the selection of the host material is crucial and important.

[0005] Due to the dual-body material structure, energy loss is reduced by optimizing the exciton recombination path, thus achieving low driving voltage. The exciton dispersion effect reduces the triplet annihilation probability, directly improving luminescence efficiency. The three-dimensional regularity of the structure improves the thermal stability of the material, reduces the risk of degradation, and extends the lifespan of the device.

[0006] Therefore, how to develop a long-life, high-efficiency, low-driving-voltage organic electroluminescent material with dual host structure, its preparation method, and organic electroluminescent devices are technical problems that urgently need to be solved by those skilled in the art. Summary of the Invention

[0007] In view of the shortcomings of the prior art, the present invention aims to provide an organic electroluminescent compound, an organic electroluminescent material containing two host materials, and a light-emitting device, which have high luminous efficiency and long lifespan characteristics by using a specific combination of compounds as host materials.

[0008] To achieve this objective, the present invention adopts the following technical solution:

[0009] On one hand, the present invention provides an organic electroluminescent compound having the structure shown in general formula 1:

[0010] ;

[0011] in:

[0012] Ar1 and Ar2 are each independently selected from substituted or unsubstituted C6-C42 aryl and substituted or unsubstituted C3-C30 heteroaryl, wherein the heteroatom in the heteroaryl is selected from one or a combination of at least two of O, Se, N, P, and Si;

[0013] L1 and L2 are independently selected from chemically bonded, substituted or unsubstituted C6-C30 aryl groups, substituted or unsubstituted C3-C30 heteroaryl groups, wherein the heteroatom in the heteroaryl group is selected from one or a combination of at least two of O, Se or N;

[0014] R1 can be selected from hydrogen, substituted or unsubstituted C6-C42 aryl, substituted or unsubstituted C3-C30 heteroaryl, wherein the heteroatom in the heteroaryl is selected from one or a combination of at least two of O, S or N, and R1 can be substituted or fused with the adjacent benzene ring.

[0015] A is selected from the following structure:

[0016] ;

[0017] All hydrogen atoms in Formula 1 may be completely unsubstituted by deuterium, completely substituted by deuterium, or partially substituted by deuterium.

[0018] The specific general formula is as follows:

[0019] ;

[0020] Furthermore, Ar1 and Ar2 are each independently selected from substituted or unsubstituted C6-C24 aryl groups, substituted or unsubstituted C3-C18 heteroaryl groups, wherein the heteroatom is selected from one or a combination of at least two of O, Se, N, P or Si; substituted or unsubstituted oxyphospho group; substituted or unsubstituted silyl group;

[0021] L1 and L2 are independently selected from chemical bonds, substituted or unsubstituted C6-C18 aryl groups, substituted or unsubstituted C3-C18 heteroaryl groups, respectively, wherein the heteroatom is selected from one or a combination of at least two of O, Se or N;

[0022] R1 may be selected from hydrogen, substituted or unsubstituted C6-C18 aryl, substituted or unsubstituted C3-C18 heteroaryl, wherein the heteroatom in the heteroaryl is selected from one or a combination of at least two of O, S or N, and R1 may be substituted or fused with an adjacent benzene ring.

[0023] Preferably, R1 is selected from hydrogen, substituted or unsubstituted phenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted benzothiophene, or substituted or unsubstituted benzofuran.

[0024] Preferably, L1 and L2 are selected from the following: a linking bond, a substituted or unsubstituted phenyl group or a substituted or unsubstituted naphthyl group; a substituted or unsubstituted dibenzofuranyl group or a substituted or unsubstituted dibenzothiophene group.

[0025] The substituents of the "substituted" group are selected from one or a combination of at least two of the following: deuterium, fluorine, cyano, C1-C10 alkyl, C1-C10 alkoxy, C3-C10 cycloalkyl, or C6-C12 aryl.

[0026] According to one embodiment of the present invention, the Ar1 and Ar2 are preferably derived from the following groups, or groups further substituted with deuterium:

[0027]

[0028] The dashed lines represent the bonding sites of the functional groups.

[0029] In this invention, heteroaryl is a monocyclic aromatic group or a polycyclic aromatic system comprising at least one heteroatom, wherein the heteroatom includes, but is not limited to, one or a combination of at least two of O, Se, N, Si or P.

[0030] According to one embodiment of the present invention, the organic electroluminescent compound has the following structure, but is not limited to the following structure:

[0031] .

[0032] The above is the specific structural formula of the first main material. The present invention preferably uses the above structure, but is not limited to it.

[0033] On the other hand, the present invention provides a dual-host material, the dual-host material comprising a first host material and a second host material, wherein the first host material is an organic electroluminescent compound as described above, and the second host compound has the structure shown in Formula 2-1 or Formula 2-2:

[0034] ;

[0035] Among them, ring B is selected from substituted or unsubstituted benzene and substituted or unsubstituted naphthalene;

[0036] L3 to L6 are independently selected from the linking bond, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C6-C30 heteroaryl, and the heteroatom is one or more of O, S, and N;

[0037] Ar1 to Ar4 are each independently selected from substituted or unsubstituted C6-C30 aryl groups, substituted or unsubstituted C6-C30 heteroaryl groups, wherein the heteroaryl group includes a monocyclic aromatic group and a polycyclic aromatic system with at least one heteroatom, and the heteroatom is one or more of O, S, and N; substituted or unsubstituted C10-C30 fused ring groups.

[0038] In Formula II-1 and Formula II-2, all hydrogen atoms can be independently substituted with deuterium or not substituted with deuterium.

[0039] Preferably, L3 to L6 are each independently selected from a linking bond, a substituted or unsubstituted C6-C18 aryl group, and a substituted or unsubstituted C6-C18 heteroaryl group, wherein the heteroatom is selected from one or more of O, S, and N;

[0040] Preferably, Ar1 to Ar4 are each independently selected from substituted or unsubstituted C6-C18 aryl groups, substituted or unsubstituted C6-C18 heteroaryl groups, the heteroaryl group comprising a monocyclic aromatic group and a polycyclic aromatic system with at least one heteroatom, the heteroatom being one or more of O, S, and N; or substituted or unsubstituted C10-C18 fused ring groups.

[0041] More preferably, L3, L4, L5, and L6 are each independently selected from any one of the following: a linking bond, a substituted or unsubstituted phenylene group, a substituted or unsubstituted naphthylene group, a substituted or unsubstituted thiophene group, and a substituted or unsubstituted furanylene group;

[0042] More preferably, Ar1, Ar2, Ar3, and Ar4 are each independently selected from substituted or unsubstituted phenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted biphenyl, substituted or unsubstituted furanyl, substituted or unsubstituted thiophene, substituted or unsubstituted cyclohexylphenyl, substituted or unsubstituted furanyl-phenyl, substituted or unsubstituted furanyl-deuterated phenyl, substituted or unsubstituted benzonaphthyl, substituted or unsubstituted methylphenyl, substituted or unsubstituted tert-butylphenyl, substituted or unsubstituted tert-butylbiphenyl, substituted or unsubstituted fluorenyl, substituted or unsubstituted terphenyl, substituted or unsubstituted benzofluorene, substituted or unsubstituted phenanthryl, substituted or unsubstituted phenylnaphthalene, substituted or unsubstituted dibenzofuranyl, substituted or unsubstituted dibenzothiophene, substituted or unsubstituted dimethylfluorenyl, substituted or unsubstituted diphenylfluorenyl, or the following groups, wherein the linkage position of the groups is any substituted position;

[0043] .

[0044] The substituted or unsubstituted group in the "substituted or unsubstituted" is selected from one or more of the following: deuterium, cyano, methyl, C6-C24 aryl, C6-C24 heteroaryl, wherein the heteroatom is selected from one or two of O, S, and N.

[0045] Furthermore, the compound shown in Formula II is a compound having the structures shown in Formulas II-A to II-H as follows:

[0046] ;

[0047] In this invention, the second host compound is any one of the compounds shown in formulas G001 to G216, but is not limited thereto:

[0048] ;

[0049] Where D represents deuterium.

[0050] The above is the specific structural formula of the second main material. The present invention preferably uses the above structure, but is not limited to it.

[0051] Preferably, the mass ratio of the first main material and the second main material is (10~90):(90~10), for example, 10:90, 15:85, 20:80, 25:75, 30:70, 35:65, 40:60, 45:55, 50:50, 60:40, 70:30, 80:20 or 90:10, etc., preferably 30~70:70~30, more preferably 60~40:40~60; for example, 40:60, 45:55, 50:50, 55:45, 60:40.

[0052] This invention also provides a method for preparing an organic electroluminescent material containing two host materials, comprising synthesizing the first host material and the second host material, the specific steps of which are as follows:

[0053] (a) Synthesis of the first main material:

[0054] 1. Synthesis of the first main material, general formula 1

[0055] ;

[0056] (1) Specific preparation method of the first main material with general formula 1-1

[0057] Under nitrogen protection, reactant 1 (1 eq), reactant 2 (1-1.1 eq), and potassium acetate (2-3 eq) were weighed and added to the reaction system. 1,4-Dioxane and catalysts tris(dibenzylacetone)palladium (0.02-0.04 eq) and X-Phos (2-bicyclohexylphosphine-2',4',6'-triisopropylbiphenyl, 0.16-0.32 eq) were added. The mixture was refluxed at 100°C for 24 h under nitrogen protection. After the reaction was completed, the mixture was cooled to 25°C, purified water was added, and the mixture was stirred and allowed to stand for separation. After separation, the mixture was purified by column chromatography to obtain the intermediate compound of general formula 1-1.

[0058] (2) Specific preparation method of the first main material formula 1-2

[0059] Under nitrogen protection, intermediate compound of general formula 1-1 (1 eq), reactant 3 (1-1.2 eq), potassium carbonate (2-3 eq) were weighed and added to the reaction system. Toluene, ethanol, water (volume ratio 2:1:1) and tetra(triphenylphosphine)palladium (0.02-0.04 eq) were added. The mixture was refluxed at 100°C for 24 h under nitrogen protection. After the reaction was completed, the mixture was cooled to 25°C, purified water was added, and the mixture was stirred and allowed to stand for separation. After separation, the mixture was purified by column chromatography to obtain intermediate compound of general formula 1-2.

[0060] (3) Specific preparation methods of the first main material formula 1-3

[0061] Under nitrogen protection, intermediate compound of general formula 1-2 (1 eq), (methoxymethyl)triphenylphosphine chloride (1-1.5 eq) and tetrahydrofuran were weighed and added to a reaction vessel and stirred at room temperature for 10-30 minutes. Potassium tert-butoxide solution (1-1.2 eq) was slowly added dropwise at -5-0℃, and then the temperature was slowly increased. After stirring at room temperature for 3-4 hours, distilled water was added. After the reaction was completed, the organic layer was extracted with ethyl acetate and the organic phase was dried with sodium sulfate. The solvent was removed by rotary evaporator and purified by column chromatography to obtain intermediate compound of general formula 1-3.

[0062] (4) Specific preparation methods of the first main material according to general formula 1-4

[0063] Under nitrogen protection, intermediate compounds of general formula 1-3 (1 eq), boron trifluoride ether (0.1-0.2 eq) and dichloromethane were weighed and added to a reaction vessel and stirred at 23-28°C for 3-4 hours. After the reaction was completed, the organic layer was extracted with dichloromethane and water, and then the organic layer was dried with sodium sulfate. The solvent was removed by rotary evaporator and purified by column chromatography to obtain intermediate compounds of general formula 1-4.

[0064] (5) Specific preparation methods of the first main material according to general formula 1-5

[0065] Under nitrogen protection, intermediate compounds of general formula 1-4 (1 eq), reactant 4 (1-1.2 eq), sodium tert-butoxide (1.5-3 eq) were weighed and added to the reaction system. Toluene (dry) and catalysts tris(dibenzylacetone)dipalladium (0.02-0.04 eq) and 50% tri-tert-butylphosphine (0.04-0.08 eq) were added. The mixture was refluxed at 120°C for 24 h under nitrogen protection. After the reaction was completed, the mixture was cooled to 25°C, purified water was added, and the mixture was stirred and allowed to stand for separation. After separation, the mixture was purified by column chromatography to obtain intermediate compounds of general formula 1-5.

[0066] (6) Specific preparation method of the first main material of general formula 1

[0067] Under nitrogen protection, intermediate compounds of general formula 1-5 (1 eq), reactant 5 (1-1.2 eq), and potassium carbonate (2-3 eq) were weighed and added to the reaction system. Tetrahydrofuran, water, and catalyst tetra(triphenylphosphine)palladium (0.02-0.04 eq) were added. The mixture was refluxed at 90°C for 24 h under nitrogen protection. After the reaction was completed, the mixture was cooled to 25°C, purified water was added, and the mixture was stirred and allowed to stand for separation. After separation, the mixture was purified by column chromatography to obtain the compound of general formula 1 shown.

[0068] The reaction route is shown above. In the reactant series 1 and reactant series 3, Hal can be arbitrarily and independently selected from Cl or Br, and can simultaneously represent 1-2 halogen linkage sites.

[0069] (II) Synthesis of the second main material:

[0070] 1. Synthesis of the second main material using general formula 2-1

[0071] (1) The reaction route of the structure shown in Equation 2-1 is as follows:

[0072] ;

[0073] Specific preparation methods include:

[0074] Under nitrogen protection, reactant A (1 eq), reactant B (1 eq), and sodium tert-butoxide (1.5 eq) were added to the reaction system, along with toluene, catalyst tris(dibenzylacetone)dipalladium (0.02 eq), and ligand 50% tri-tert-butylphosphine (0.04 eq). The reaction was refluxed at 110–120 °C for 18–24 h. After the reaction was completed, the temperature was lowered to 25 °C, purified water was added, and the mixture was stirred and allowed to stand for separation. After separation, the mixture was purified by column chromatography to obtain the intermediate compound shown in Formula 2-1-1.

[0075] Under nitrogen protection, intermediate compound 2-1-1 (1 eq), reactant C (1 eq), sodium tert-butoxide (1.5 eq) were added to the reaction system, along with toluene, catalyst tris(dibenzylacetone)dipalladium (0.02 eq), and ligand 50% tri-tert-butylphosphine (0.04 eq). The reaction was refluxed at 110–120 °C for 18–24 h. After the reaction was completed, the temperature was lowered to 25 °C, purified water was added, and the mixture was stirred and allowed to stand for separation. After separation, the mixture was purified by column chromatography to obtain a compound with the structure shown in Formula 2-1.

[0076] Wherein, L3, L4, Ar1, and Ar2 are each independently selected from the same range as Formula II-1; X is selected from halogens; the halogens include fluorine, chlorine, bromine, or iodine, preferably chlorine or bromine, and most preferably chlorine.

[0077] (2) The reaction route of the structure shown in Equation 2-2 is as follows:

[0078] ;

[0079] Specific preparation methods include:

[0080] Under nitrogen protection, reactants D (1 eq), E (1 eq), and sodium tert-butoxide (1.5 eq) were added to the reaction system, along with toluene, the catalyst tris(dibenzylacetone)dipalladium (0.02 eq), and the ligand 50% tri-tert-butylphosphine (0.04 eq). The reaction was refluxed at 110–120 °C for 18–24 h. After the reaction was completed, the temperature was lowered to 25 °C, purified water was added, and the mixture was stirred and allowed to stand for separation. After separation, the mixture was purified by column chromatography to obtain the intermediate compound shown in Formula 2-2-1.

[0081] Under nitrogen protection, intermediate compound II-2-1 (1 eq), reactant F (1 eq), sodium tert-butoxide (1.5 eq) were added to the reaction system, along with toluene, catalyst tris(dibenzylacetone)dipalladium (0.02 eq), and ligand 50% tri-tert-butylphosphine (0.04 eq). The reaction was refluxed at 110–120 °C for 18–24 h. After the reaction was completed, the temperature was lowered to 25 °C, purified water was added, and the mixture was stirred and allowed to stand for separation. After separation, the mixture was purified by column chromatography to obtain a compound with the structure shown in Formula 2-2.

[0082] In this context, ring B, L5, L6, Ar3, and Ar4 are each independently selected from the same range as in formula II-2; X is selected from halogens; the halogens include fluorine, chlorine, bromine, or iodine, preferably chlorine or bromine, and most preferably chlorine.

[0083] On the other hand, the present invention provides an organic electroluminescent material, which includes a dual host material and a doped material as described above.

[0084] In the dual-body organic electroluminescent material of the present invention, the mass ratio of the first host material and the second host material is (10~90):(90~10), for example, 10:90, 15:85, 20:80, 25:75, 30:70, 35:65, 40:60, 45:55, 50:50, 60:40, 70:30, 80:20 or 90:10, etc., preferably 30~70:70~30, more preferably 60~40:40~60; for example, 40:60, 45:55, 50:50, 55:45, 60:40.

[0085] In one embodiment of the present invention, the mass ratio of the dual host material to the doped material in the organic electroluminescent material is (5~199):1; for example, 5:1, 15:1, 25:1, 35:1, 45:1, 55:1, 65:1, 75:1, 85:1, 95:1, 105:1, 115:1, 125:1, 135:1, 145:1, 155:1, 165:1, 175:1, 185:1 or 199:1, etc., preferably (5~100):1, more preferably (5~15):1.

[0086] The present invention also provides an organic electroluminescent device, the organic electroluminescent device comprising a first electrode, a second electrode, and an organic material layer disposed between the first electrode and the second electrode, the organic material layer comprising the organic electroluminescent compound as described above, or the dual host material or the organic electroluminescent material.

[0087] Preferably, the organic material layer includes a light-emitting layer, which includes the organic electroluminescent compound as described above, or the dual host material or the organic electroluminescent material.

[0088] Preferably, the organic material layer further includes any one or a combination of at least two of the following: a hole injection layer, a hole transport layer, a light-emitting layer, a hole blocking layer, an electron transport layer, and an electron injection layer.

[0089] In one embodiment of the present invention, the organic electroluminescent device includes a first electrode, a hole injection layer, a hole transport layer, a light-emitting layer, a hole blocking layer, an electron transport layer, an electron injection layer, and a second electrode arranged sequentially; the material of the light-emitting layer includes the dual-host material or the organic electroluminescent material.

[0090] In one embodiment of the present invention, the method for preparing the light-emitting layer includes, but is not limited to, forming the light-emitting layer from the organic electroluminescent material by solution coating and vacuum deposition.

[0091] In one embodiment of the present invention, the solution coating method includes one or more of spin coating, dip coating, inkjet printing, screen printing, and spraying, but is not limited thereto.

[0092] In one embodiment of the present invention, the first electrode is an anode.

[0093] As an anode material, a material with a high work function is preferred in order to enable holes to be successfully injected into the organic layer.

[0094] In one embodiment of the present invention, the anode material includes: a metal, such as vanadium, chromium, copper, zinc, or an alloy thereof; a metal oxide, such as zinc oxide, indium oxide, indium tin oxide (ITO), or indium zinc oxide (IZO); a combination of metal and oxide, such as ZnO / Al or SnO2 / Sb; a conductive polymer, such as poly(3-methylthiophene), polypyrrole, or polyaniline; but is not limited thereto.

[0095] In some embodiments of the present invention, the anode is an ITO anode.

[0096] In one embodiment of the present invention, the material of the hole injection layer is selected from one or more of metalloporphyrin, oligothiophene, arylamine-based organic materials, benzonitrile-based organic materials, quinacridone-based organic materials, polyaniline-based and polythiophene-based conductive polymers.

[0097] In one embodiment of the invention, the material of the hole injection layer is a material that receives holes from the anode at a low voltage, and the highest occupied molecular orbital (HOMO) of the hole injection layer material is preferably between the work function of the anode material and the HOMO of the surrounding organic material layer.

[0098] In one embodiment of the invention, the material of the hole transport layer is selected from one or more of arylamine-based organic materials, conductive polymers, and block copolymers having both conjugated and non-conjugated portions.

[0099] In one embodiment of the present invention, the material of the hole transport layer is capable of receiving holes from the anode or hole injection layer and transporting the holes to the light-emitting layer, and has a high hole mobility.

[0100] In one embodiment of the present invention, the electron transport layer is selected from one or more of 8-hydroxyquinoline Al complexes, organic free radical compounds, but is not limited thereto.

[0101] In one embodiment of the present invention, the thickness of the electron transport layer is from 1 nm to 50 nm, for example, 1 nm, 2 nm, 4 nm, 6 nm, 8 nm, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm.

[0102] The electron transport layer prevents a decrease in electron transport characteristics and avoids an increase in driving voltage due to excessive thickness, thus promoting electron transport. The material of the electron transport layer is used to receive electrons from the cathode and transport them to the light-emitting layer, exhibiting high electron mobility.

[0103] The electron injection layer can promote electron injection, and the material of the electron injection layer is preferably capable of transporting electrons, has an electron injection effect from the cathode, has an excellent electron injection effect on the light-emitting layer or light-emitting material, prevents excitons generated in the light-emitting layer from migrating to the hole injection layer, and also has excellent thin film forming ability.

[0104] In one embodiment of the present invention, the electron-injected layer is selected from one or more of fluorenone, anthraquinone dimethane, biphenylquinone, thiamethane dioxide, imidazole, perylenetetracarboxylic acid, fluorenemethane, anthrone or its derivatives, metal complexes, and nitrogen-containing five-membered ring derivatives, but is not limited thereto.

[0105] In one embodiment of the present invention, the second electrode is a cathode.

[0106] As a cathode material, a material with a low work function is generally preferred in order to facilitate the injection of electrons into the organic layer.

[0107] In one embodiment of the present invention, specific examples of cathode materials include: metals, such as magnesium, calcium, sodium, potassium, titanium, indium, yttrium, lithium, gadolinium, aluminum, silver, tin, lead, and other metals or alloys thereof; multilayer structure materials, such as LiF / Al or LiO2 / Al; but not limited thereto.

[0108] In some embodiments of the present invention, the material used as the cathode may be Al.

[0109] In one embodiment of the present invention, the organic electroluminescent device may be a top-emitting type, a bottom-emitting type, or a dual-sided emitting type.

[0110] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0111] Compared with the prior art, the present invention has the following beneficial effects:

[0112] This invention provides an organic electroluminescent material with dual host materials, which is a composite of a first host compound with a specific structure and a second host compound with a specific structure. The first host compound (Formula 1) with a specific structure has a good conjugated structure, carbazole is a typical hole transport unit, and triazine has strong electron accepting ability and high thermal stability. After the three are connected, an effective charge transport channel is formed in the molecule, which can simultaneously balance the transport rate of holes and electrons, enhance the thermal stability of the molecule, reduce the device performance degradation caused by thermal decomposition, and improve the life and performance of organic semiconductor devices.

[0113] The second host carbazole compound (Formula 2) has high hole injection transport energy, and hole injection transport can be controlled at a high level by changing the bonding pattern of the carbazole ring and the type / number of substituents for the backbone.

[0114] Therefore, by using the compound formed by mixing the first and second host compounds to create the dual-host material, the injection amount of both charges into the organic layer can be adjusted to a preferred range, thereby achieving better device characteristics. Furthermore, applying this dual-host material compound to the light-emitting layer material of an organic electroluminescent device can reduce the driving voltage, improve the luminous efficiency of the organic electroluminescent device, and extend its lifespan. Attached Figure Description

[0115] Figure 1 This is the hydrogen nuclear magnetic resonance spectrum of compound H225, the first host material prepared in this invention. Detailed Implementation

[0116] 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.

[0117] Unless otherwise stated, the raw materials and reagents used in the following examples are all commercially available products.

[0118] Compound H225, used to prepare the first host material

[0119] Under nitrogen protection, raw material A: 2-bromo-7-chloro-1-naphthal (1 eq, CAS: 1331895-48-7), raw material B: pinacol diboronate (1 eq, CAS: 73183-34-3), and potassium acetate (2.5 eq) were weighed and added to the reaction system. Nitrogen was replaced, and 1,4-dioxane and catalysts tris(dibenzylacetone)dipalladium (0.02 eq) and X-Phos (0.16 eq) were added. The mixture was refluxed at 100 °C for 24 h under nitrogen protection. After the reaction was completed, the mixture was cooled to 25 °C, purified water was added, and the mixture was stirred and allowed to stand for separation. After separation, the mixture was purified by column chromatography to obtain the intermediate compound H225-1 shown, with a yield of 81%.

[0120] Under nitrogen protection, intermediate compound H225-1 (1 eq) was weighed, and raw material C: p-bromoiodobenzene (1 eq, CAS: 73183-34-3) and potassium carbonate (2 eq) were added to the reaction system. Toluene, ethanol, water (volume ratio 2:1:1) and catalyst tetra(triphenylphosphine)palladium (0.04 eq) were added. The mixture was refluxed at 90°C for 24 h under nitrogen protection. After the reaction was completed, the mixture was cooled to 25°C, purified water was added, and the mixture was stirred and allowed to stand for separation. After separation, the mixture was purified by column chromatography to obtain intermediate compound H225-2 as shown, with a yield of 68.5%.

[0121] Under nitrogen protection, intermediate compound H225-2 (1 eq), (methoxymethyl)triphenylphosphine chloride (1.3 eq), and tetrahydrofuran were weighed and added to a reaction vessel and stirred at room temperature for 10 minutes. Potassium tert-butoxide solution (1 eq) was slowly added dropwise at 0°C, and then the temperature was slowly increased. After stirring at room temperature for 3 hours, distilled water was added. After the reaction was completed, the organic layer was extracted with ethyl acetate, the organic phase was dried with sodium sulfate, the solvent was removed by rotary evaporator, and the mixture was purified by column chromatography to obtain intermediate compound H225-3, yield: 63%.

[0122] Under nitrogen protection, intermediate compound H225-3 (1 eq), boron trifluoride ether (0.15 eq), and dichloromethane were weighed and added to a reaction vessel and stirred at 25°C for 3 hours. After the reaction was completed, the organic layer was extracted with dichloromethane and water, then dried with sodium sulfate, the solvent was removed by rotary evaporator, and the mixture was purified by column chromatography to obtain intermediate compound H225-4, yield: 58%.

[0123] Under nitrogen protection, intermediate compound H225-4 (1 eq), starting material D: 9H-carbazole (1 eq, CAS: 34479-78-2), and sodium tert-butoxide (2 eq) were weighed and added to the reaction system. Dry toluene, catalyst tris(dibenzylacetone) bispalladium (0.02 eq), and 50% tri-tert-butylphosphine (0.044 eq) were added. Nitrogen was purged, and the mixture was refluxed at 120°C for 24 h under nitrogen protection. After the reaction was completed, the mixture was cooled to 25°C, purified water was added, and the mixture was stirred for 30 minutes. The mixture was allowed to stand and separate into layers. The layers were separated and purified by column chromatography to obtain intermediate compound H225-5, yield: 83%.

[0124] Under nitrogen protection, intermediate compound H225-5 (1 eq), raw material E: (4,6-diphenyl-1,3,5-triazin-2-yl)boronic acid (1.1 eq) (CAS: 1251825-65-6), and potassium carbonate (3 eq) were weighed and added to the reaction system. Tetrahydrofuran, water, and catalyst tetra(triphenylphosphine)palladium (0.04 eq) were added. The mixture was refluxed at 90°C for 24 h under nitrogen protection. After the reaction was completed, the mixture was cooled to 25°C, purified water was added, and the mixture was stirred and allowed to stand for separation. After separation, the mixture was purified by column chromatography to obtain the final product H225; yield 73.5%. HPLC: 99.90%; mass spectrometry: 624.37; elemental analysis: C: 86.52%; H: 4.56%; N: 9.02%.

[0125] The synthesis route is as follows:

[0126] ;

[0127] The proton NMR spectrum of compound H225, the first host material, is shown below. Figure 1 .

[0128] Compound G096, used to prepare the second host material

[0129] Under nitrogen protection, raw material A (CAS: 1346669-44-0, 1 eq), raw material B (1 eq, CAS: 2113-57-7), and sodium tert-butoxide (149.42 mmol) were weighed into a reaction flask. Toluene was added, and catalysts Pd2(dba)3 (0.02 eq) and P(t-Bu)3 (0.04 eq) were added under nitrogen protection. The mixture was refluxed at 120 °C for 24 h under nitrogen protection, then cooled to 25 °C, purified water was added, and the mixture was stirred for 30 min. After standing and separating the layers, the mixture was separated and subjected to column chromatography to obtain the second main compound H2-96 (yield 68%, HPLC > 99%, mass spectrometry: measured value 636.46). Elemental analysis: C: 90.52%; H: 5.03%; N: 4.41%.

[0130] The synthesis route is as follows:

[0131] ;

[0132] In addition, it should be noted that other compounds of the present invention can be obtained by referring to the synthesis methods of the examples listed above, so they will not be listed one by one here.

[0133] Fabrication of organic electroluminescent devices

[0134] The fabrication method of organic electroluminescent devices is as follows:

[0135] (1) The ITO (indium tin oxide) glass substrate with a thickness of 1500 angstroms was washed twice with distilled water and ultrasonically washed for 30 minutes. Then it was washed twice with distilled water and ultrasonically washed for 10 minutes. After washing, it was ultrasonically washed sequentially with methanol, acetone and isopropanol (5 minutes each time), dried, and then transferred to a plasma cleaner for 5 minutes to obtain the ITO anode.

[0136] (2) In the vapor deposition machine, HIL is vacuum vapor deposited on the ITO anode surface obtained in step (1) with a thickness of 700 angstroms to obtain a hole injection layer.

[0137] (3) Vacuum vapor deposition of HTL on the surface of the hole injection layer obtained in step (2), with HTL1 and HTL2 having a thickness of 50 angstroms and a thickness of 700 angstroms to form a hole transport layer.

[0138] (4) A light-emitting layer material is deposited on the surface of the hole transport layer by evaporation using a multi-source co-evaporation method with a linear gradient co-evaporation thickness of 300 angstroms to obtain the light-emitting layer. The light-emitting layer material includes a dual host material and a doped material. The mass ratio of the first host compound and the second host compound in the dual host material is 60:40, and the mass ratio of the dual host material to the doped material is 10:1. The dual host materials are the host materials provided in Device Examples 1-28, Comparative Examples 1-7, and Parallel Comparative Examples 1-10, respectively.

[0139] (5) HBL is deposited on the surface of the light-emitting layer obtained in step (4) with a thickness of 100 angstroms to form a hole blocking layer.

[0140] (6) Vacuum vapor deposition of ETL on the surface of the hole blocking layer obtained in step (5) with a thickness of 300 angstroms is obtained to obtain the electron transport layer.

[0141] (7) A Liq layer with a thickness of 15 angstroms is vacuum-deposited on the surface of the electron transport layer obtained in step (6); an electron injection layer is obtained.

[0142] (8) A 1200 angstrom layer of Al is deposited on the surface of the electron injection layer obtained in step (7) to form a cathode, thereby obtaining the organic electroluminescent device.

[0143] Materials used in each functional layer of the device:

[0144] .

[0145] Device Examples 1-42, Comparative Examples 1-18, and Parallel Comparative Examples 1-6:

[0146] Device Examples 1-42 employ the dual host material of the present invention. The combination of the dual host materials is shown in Table 2. For the dual host material scheme including a compound of the first host material and a compound of the second host material, the mass ratio of the compound of the first host material and the compound of the second host material is 60:40.

[0147] Comparative Examples 1-18 used one or two compounds with the structures shown in Table 1 as the host material.

[0148] In parallel comparative examples 1-6, a host material compound with the structure shown in general formula 1 or general formula 2 of the present invention and a compound with the structure shown in Table 1 are respectively matched.

[0149] In Table 2, "-" indicates that the compound is not present in the host material; the structures of E and F are shown below.

[0150] The compounds used in the comparative examples are shown in Table 1 below:

[0151] Table 1

[0152] ;

[0153] The driving voltage, luminous efficiency, and time (lifetime; T95) of the organic electroluminescent device at a brightness of 15000 nits were tested. The test results are shown in Table 2.

[0154] Table 2

[0155]

[0156]

[0157]

[0158] As can be seen from device examples 1-36, when the main material of the light-emitting layer is a compound of the first main material and the second main material of the present invention, its application in the device can significantly improve the luminous efficiency and service life.

[0159] As can be seen from the comparison between Comparative Examples 1-14 and Comparative Examples 15-18, using only one of them will result in a significant reduction in the luminous efficiency of the device, a significant shortening of its lifespan, and an increase in voltage.

[0160] A comparison of the device performance of Device Examples 1-36 and Parallel Comparative Examples 1-6 shows that the organic electroluminescent devices prepared in Parallel Comparative Examples 1-6 have an efficiency of 34.7-36.1 cd / A, a driving voltage of 3.42-3.55 V, and a lifetime of 472-487 h. In contrast, the organic electroluminescent devices prepared using dual host materials in Device Examples 1-36 of the present invention have a luminous efficiency of 41.1-44.9 cd / A, significantly higher than the luminous efficiency of the devices in Parallel Comparative Examples 1-6. The driving voltage of Device Examples 1-36 of the present invention is 3.01-3.19 V, significantly lower than the driving voltage of the devices in Parallel Comparative Examples 1-6. The lifetime of the devices in Device Examples 1-36 of the present invention is 581-631 h, far exceeding the lifetime of the devices in Parallel Comparative Examples 1-6.

[0161] The main reason for this is that the present invention uses a compound of the first host material with a specific structure, which has a high electron injection transport energy. After being linked with triazine and carbazole, an effective charge transport channel is formed within the molecule, which can simultaneously balance the transport rates of holes and electrons, enhance the thermal stability of the molecule, reduce the device performance degradation caused by thermal decomposition, and improve the lifespan and performance of organic semiconductor devices.

[0162] On the other hand, the second host carbazole compound has high hole injection transport energy, and hole injection transport can be controlled at a high level by changing the bonding pattern of the carbazole ring and the type / number of substituents for the backbone.

[0163] Therefore, by using a compound of the first and second main materials of this invention, the injection amount of both charges into the organic layer can be adjusted to an optimal range, thereby achieving better device characteristics. In the case of phosphorescent EL devices, there is no energy outflow from the self-emissive layer, resulting in low voltage, high efficiency, and long lifespan.

[0164] The applicant declares that the present invention is illustrated through the above embodiments to demonstrate the materials, preparation methods, and applications of the present invention; however, 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.

Claims

1. An organic electroluminescent compound, characterized in that, The organic electroluminescent compound has the structure shown in general formula 1: ； in: Ar1 and Ar2 are each independently selected from substituted or unsubstituted C6-C42 aryl and substituted or unsubstituted C3-C30 heteroaryl, wherein the heteroatom in the heteroaryl is selected from one or a combination of at least two of O, Se, N, P, and Si; L1 and L2 are independently selected from chemically bonded, substituted or unsubstituted C6-C30 aryl groups, substituted or unsubstituted C3-C30 heteroaryl groups, wherein the heteroatom in the heteroaryl group is selected from one or a combination of at least two of O, Se or N; R1 is selected from hydrogen, substituted or unsubstituted C6-C42 aryl, substituted or unsubstituted C3-C30 heteroaryl, wherein the heteroatom in the heteroaryl is selected from one or a combination of at least two of O, S or N, and R1 is connected to the benzene ring on the carbazole group by a single bond or fused with the benzene ring. A is selected from the following structure: ； All hydrogen atoms in Formula 1 may be completely unsubstituted by deuterium, completely substituted by deuterium, or partially substituted by deuterium.

2. The organic electroluminescent compound according to claim 1, characterized in that, Ar1 and Ar2 are each independently selected from substituted or unsubstituted C6-C24 aryl, substituted or unsubstituted C3-C18 heteroaryl, wherein the heteroatom is selected from one or a combination of at least two of O, Se, N, P or Si; substituted or unsubstituted oxyphosphoyl; substituted or unsubstituted silyl. L1 and L2 are independently selected from chemical bonds, substituted or unsubstituted C6-C18 aryl groups, substituted or unsubstituted C3-C18 heteroaryl groups, respectively, wherein the heteroatom is selected from one or a combination of at least two of O, Se or N; R1 can be selected from hydrogen, substituted or unsubstituted C6-C18 aryl, substituted or unsubstituted C3-C18 heteroaryl, wherein the heteroatom in the heteroaryl is selected from one or a combination of at least two of O, S or N, and R1 can be substituted or fused with the adjacent benzene ring. Preferably, R1 is selected from hydrogen, substituted or unsubstituted phenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted benzothiophene, or substituted or unsubstituted benzofuran.

3. The organic electroluminescent compound according to claim 1 or 2, characterized in that, L1 and L2 are selected from the following: a linking bond, a substituted or unsubstituted phenyl group or a substituted or unsubstituted naphthyl group; a substituted or unsubstituted dibenzofuranyl group or a substituted or unsubstituted dibenzothiophene group; The substituents of the "substituted" group are selected from one or a combination of at least two of the following: deuterium, fluorine, cyano, C1-C10 alkyl, C1-C10 alkoxy, C3-C10 cycloalkyl, or C6-C12 aryl.

4. The organic electroluminescent compound according to claim 1, characterized in that, The Ar1 and Ar2 are preferably derived from the following groups, or groups further substituted with deuterium: ； The dashed lines represent the bonding sites of the functional groups.

5. The organic electroluminescent compound according to claim 1, characterized in that, The organic electroluminescent compound is any one of the following compounds: 。 6. A dual-body material, characterized in that, The dual host material comprises a first host material and a second host material, wherein the first host material is an organic electroluminescent compound according to any one of claims 1-5, and the second host compound has the structure shown in formula 2-1 or formula 2-2: ； Among them, ring B is selected from substituted or unsubstituted benzene and substituted or unsubstituted naphthalene; L3 to L6 are independently selected from the linking bond, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C6-C30 heteroaryl, and the heteroatom is one or more of O, S, and N; Ar1 to Ar4 are each independently selected from substituted or unsubstituted C6-C30 aryl groups, substituted or unsubstituted C6-C30 heteroaryl groups, wherein the heteroaryl group includes a monocyclic aromatic group and a polycyclic aromatic system with at least one heteroatom, and the heteroatom is one or more of O, S, and N; substituted or unsubstituted C10-C30 fused ring groups. In Formula II-1 and Formula II-2, all hydrogen atoms can be independently substituted with deuterium or not substituted with deuterium.

7. The dual-body material according to claim 6, characterized in that, L3 to L6 are each independently selected from a linking bond, a substituted or unsubstituted C6-C18 aryl group, a substituted or unsubstituted C6-C18 heteroaryl group, wherein the heteroatom is selected from one or more of O, S, and N; Preferably, Ar1 to Ar4 are each independently selected from substituted or unsubstituted C6-C18 aryl groups, substituted or unsubstituted C6-C18 heteroaryl groups, wherein the heteroaryl group comprises a monocyclic aromatic group and a polycyclic aromatic system with at least one heteroatom, and the heteroatom is one or more of O, S, and N; or substituted or unsubstituted C10-C18 fused ring groups. More preferably, L3, L4, L5, and L6 are each independently selected from any one of the following: a linking bond, a substituted or unsubstituted phenylene group, a substituted or unsubstituted naphthylene group, a substituted or unsubstituted thiophene group, and a substituted or unsubstituted furanylene group; More preferably, Ar1, Ar2, Ar3, and Ar4 are each independently selected from substituted or unsubstituted phenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted biphenyl, substituted or unsubstituted furanyl, substituted or unsubstituted thiophene, substituted or unsubstituted cyclohexylphenyl, substituted or unsubstituted furanyl-phenyl, substituted or unsubstituted furanyl-deuterated phenyl, substituted or unsubstituted benzonaphthyl, substituted or unsubstituted methylphenyl, substituted or unsubstituted tert-butylphenyl, substituted or unsubstituted tert-butylbiphenyl, substituted or unsubstituted fluorenyl, substituted or unsubstituted terphenyl, substituted or unsubstituted benzofluorene, substituted or unsubstituted phenanthryl, substituted or unsubstituted phenylnaphthalene, substituted or unsubstituted dibenzofuranyl, substituted or unsubstituted dibenzothiophene, substituted or unsubstituted dimethylfluorenyl, substituted or unsubstituted diphenylfluorenyl, or the following groups, wherein the linkage position of the groups is any substituted position; ； Preferably, the substituent group in "substituted or unsubstituted" is selected from one or more of the following: deuterium, cyano, methyl, C6-C24 aryl, C6-C24 heteroaryl, wherein the heteroatom is selected from one or two of O, S, and N; More preferably, the compound represented by Formula II is a compound having the structures shown in Formulas II-A to II-H: 。 8. The dual-body material according to claim 6, characterized in that, The second host compound is any one of the compounds shown in formulas G001 to G216: ； Preferably, the mass ratio of the first main material and the second main material is (10~90):(90~10), more preferably 60:40~40:

60.

9. An organic electroluminescent material, characterized in that, The organic electroluminescent material comprises a dual host material and a doped material as described in any one of claims 6-8, wherein the mass ratio of the dual host material to the doped material is (5~199):

1.

10. An organic electroluminescent device, characterized in that, The organic electroluminescent device includes a first electrode, a second electrode, and an organic material layer disposed between the first electrode and the second electrode. The organic material layer includes the organic electroluminescent compound of any one of claims 1-5, or the dual host material of any one of claims 6-8, or the organic electroluminescent material of claim 9. Preferably, the organic material layer includes a light-emitting layer, which includes an organic electroluminescent compound according to any one of claims 1-5, a dual-host material according to any one of claims 6-8, or an organic electroluminescent material according to claim 9; Preferably, the organic material layer further includes any one or a combination of at least two of the following: a hole injection layer, a hole transport layer, a light-emitting layer, a hole blocking layer, an electron transport layer, and an electron injection layer.

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