Organic electroluminescent compound, organic electroluminescent material, and organic electroluminescent device

Abstract

The present application relates to the technical field of organic electroluminescent material, in particular to an organic electroluminescent compound, an organic electroluminescent material and an organic electroluminescent device.The organic electroluminescent compound is selected from the compound shown in the following general formula (1): general formula (1); the organic electroluminescent compound can enhance the hole transport and electron transport capacity, and then can reduce the driving voltage while the service life is also enhanced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of organic electroluminescent materials, in particular to an organic electroluminescent compound, an organic electroluminescent material and an organic electroluminescent device. BACKGROUND

[0002] An organic electroluminescent device (OLED) is a self-luminescent device, which has low driving voltage, high resolution, large brightness, fast response time, and is bendable, and the production cost of raw materials is low, easy to process, and high in purity, so it is widely used in panel display device industry.

[0003] OLED display technology has been widely used in the field of smart phones and tablet computers, and in the future, the application field will also be extended to large-size fields such as televisions, so there are higher requirements for the performance of OLED such as luminous efficiency and service life. The luminescent material in OLED is the most important factor to determine the luminous efficiency of OLED. According to the different functions, it is generally divided into host material and doping material, or the host and dopant can be mixed to form a mixed luminescent material to improve color purity, luminous efficiency and stability. An organic electroluminescent device with excellent electroluminescence (EL) characteristics generally has a structure of a luminescent layer formed by doping a dopant into a host material, and when such a dopant / host material system is used as a luminescent material, the selection of the host material will significantly affect the efficiency and life of the luminescent device, therefore, selecting a suitable host material is crucial to improve or improve the luminous efficiency and service life of OLED.

[0004] As can be seen, in order to develop OLEDs with high efficiency and long service life, especially considering the EL characteristics required for medium and large OLED panels, it is urgent to develop luminescent materials that are superior to conventional luminescent materials and have excellent performance.

[0005] In view of this, the present application is proposed. SUMMARY

[0006] The purpose of the present application is to provide an organic electroluminescent compound, an organic electroluminescent material and an organic electroluminescent device. The present application provides a new organic electroluminescent compound which can enhance the hole transport and electron transport capability, thereby reducing the driving voltage while the service life is also enhanced.

[0007] The present application is realized as follows:

[0008] In a first aspect, the present application provides an organic electroluminescent compound selected from the following general formula (1):

[0009] General formula (1);

[0010] wherein A is selected from substituted or unsubstituted C6-C30 aryl; A is fused or substituted with adjacent benzene rings;

[0011] X represents any one of -NR1-, -O- and -S-; R1 is hydrogen or substituted or unsubstituted C6-C30 aryl;

[0012] L1 and L2 are each independently selected from any one of a bond, substituted or unsubstituted C6-C30 aryl and substituted or unsubstituted C6-C30 heteroaryl; wherein the heteroatom is any one of O, S and N;

[0013] Ar1 and Ar2 are each independently selected from any one of substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C6-C30 heteroaryl and substituted or unsubstituted C10-C30 fused ring group; wherein the heteroaryl includes a monocyclic aromatic group containing at least one heteroatom or a polycyclic aromatic system containing at least one heteroatom, the heteroatom being any one of O, S, N, P and Si;

[0014] all hydrogens in the compound of general formula (I) are each independently selected from protium or deuterium.

[0015] In a second aspect, an embodiment of the present application provides an organic electroluminescent material, which comprises a first host material and a second host material, the first host material being selected from the organic electroluminescent compound of claim 1, and the second host material being selected from a compound represented by general formula (2):

[0016] general formula (2);

[0017] wherein L3, L4 and L5 are each independently selected from any one of a bond, substituted or unsubstituted C6-C30 aryl and substituted or unsubstituted C6-C30 heteroaryl;

[0018] Ar3, Ar4 and Ar5 are each independently selected from any one of substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C6-C30 heteroaryl and substituted or unsubstituted C10-C30 fused ring group; wherein the heteroaryl includes a monocyclic aromatic group containing at least one heteroatom or a polycyclic aromatic system containing at least one heteroatom, the heteroatom including any one of O, S and N.

[0019] In a third aspect, an embodiment of the present application provides an organic electroluminescent device, which comprises a light-emitting layer formed by the aforementioned organic electroluminescent material.

[0020] The organic electroluminescent compound provided by the embodiment of the present application has a triazine skeleton, has a high glass transition temperature and molecular thermal stability, suitable HOMO and LUMO energy levels and a high Eg, and can improve the luminous efficiency and service life of the organic electroluminescent device. The organic electroluminescent compound further matches a second host having a triarylamine structure, which can further simultaneously enhance the hole transport and electron transport capabilities, so that when the holes are injected into the p-type host and the electrons are injected into the n-type host, the organic electroluminescent device can reduce the driving voltage, improve the luminous efficiency, and also enhance the service life. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be considered as limiting the scope. For those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0022] Figure 1 The nuclear magnetic resonance spectrum of the organic electroluminescent compound provided by the embodiment 1 of the present application. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly and completely described below. If the specific conditions are not specified in the embodiments, the conventional conditions or the conditions recommended by the manufacturer are used. If the reagents or instruments used are not specified by the manufacturer, they are all conventional products that can be purchased on the market.

[0024] In a first aspect, the embodiments of the present application provide an organic electroluminescent compound selected from the following general formula (1) shown compound:

[0025] General formula (1);

[0026] Wherein, A is selected from substituted or unsubstituted C6-C30 aryl; A is fused or substituted with adjacent benzene ring;

[0027] X represents any one of -NR1-, -O- and -S-; R1 is hydrogen or substituted or unsubstituted C6-C30 aryl;

[0028] L1 and L2 are each independently selected from any one of a bond, substituted or unsubstituted C6-C30 aryl and substituted or unsubstituted C6-C30 heteroaryl; wherein the heteroatom is any one of O, S and N;

[0029] Ar1 and Ar2 are each independently selected from any one of substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C6-C30 heteroaryl, and substituted or unsubstituted C10-C30 fused ring group; wherein the heteroaryl includes a monocyclic aromatic group containing at least one heteroatom or a polycyclic aromatic group containing at least one heteroatom, and the heteroatom is any one of O, S, N, P and Si;

[0030] All hydrogens in the compound represented by the general formula (I) are each independently selected from protium or deuterium, that is, all hydrogens in the compound are protium or all hydrogens in the compound are deuterium; or part of the hydrogens are protium and part of the hydrogens are deuterium.

[0031] The organic electroluminescent compound contains a sulfur tetra-fused ring structure as a mother nucleus structure, and the mother nucleus structure containing the sulfur tetra-fused ring is connected with a triazine group. The mother nucleus structure containing the sulfur tetra-fused ring has strong molecular rigidity, which is conducive to improving the thermal stability of the molecule. The mother nucleus structure connected with the triazine group has a certain spatial twist, which is conducive to improving the energy level and band gap of the molecule, and is conducive to inhibiting the aggregation of the molecule. Therefore, the organic electroluminescent compound has a high glass transition temperature and molecular thermal stability, suitable HOMO and LUMO energy levels, and a high Eg, which can improve the luminous efficiency and service life of the organic electroluminescent device.

[0032] Further, the organic electroluminescent compound is selected from any one of the compounds represented by the general formula (1-1) to general formula (1-3):

[0033] .

[0034] Further, A is selected from substituted or unsubstituted C6-C18 aryl; A is fused or substituted with an adjacent benzene ring. Preferably, A in the embodiments of the present application is selected from substituted or unsubstituted benzene and substituted or unsubstituted naphthalene, and is fused with an adjacent benzene ring.

[0035] Further, L1 and L2 are each independently selected from any one of a bond, substituted or unsubstituted C6-C18 aryl, and substituted or unsubstituted C6-C18 heteroaryl; wherein the heteroatom is any one of O, S and N. Preferably, L1 and L2 are each independently selected from a bond.

[0036] Further, R1 is selected from any one of hydrogen, phenyl, biphenyl and naphthyl.

[0037] Ar1 and Ar2 are each independently selected from any one of the groups represented by the following structural formula:

[0038] .

[0039] It should be noted that: (1) the above groups can be connected at any substitutable site;

[0040] (2) The hydrogen in the above group can be optionally further substituted with deuterium.

[0041] Further, the number of carbon atoms of the aryl group, the heteroaryl group, and the condensed ring group in the "substituted or unsubstituted C6-C30 aryl group", the "substituted or unsubstituted C6-C30 heteroaryl group", and the "substituted or unsubstituted C10-C30 condensed ring group" according to the embodiments of the present application indicates the total number of carbon atoms without considering the number of carbon atoms in the substituents.

[0042] The "substituted" according to the embodiments of the present application means that the substituents are connected with one or at least two substituents selected from the group consisting of deuterium, a cyano group, a methyl group, a C6-C24 aryl group, and a C6-C24 heteroaryl group, wherein the heteroatom is selected from the group consisting of O, S, and N.

[0043] Further, the organic electroluminescent compound is selected from any one of the compounds represented by the following structural formulas:

[0044]

[0045]

[0046] The above compounds are merely examples of the organic electroluminescent compounds represented by the compound of general formula (1), but the embodiments of the present application are not limited to these chemical structures, and any compound having a simple transformation of the group within the scope defined by the structural general formula (1) should be included.

[0047] The embodiments of the present application provide a method for preparing the organic electroluminescent compound described above, comprising: synthesizing according to any one of the following synthesis routes 1 to 3:

[0048] (1) Synthesis route 1:

[0049] The specific process is as follows:

[0050] (1) Reactant 1 (1 eq), reactant 2 (1-1.2 eq), sodium alcoholate such as sodium tert-butoxide (1.5-2.5 eq) were sequentially added to a reaction vessel, and then a reaction solvent such as toluene was added thereto, and a catalyst such as tris(dibenzylideneacetone)dipalladium (0.03-0.07 eq) and bis(2-diphenylphosphinophenyl)ether (0.03-0.07 eq) was added thereto under nitrogen protection, and then the temperature was raised to 40-70°C, and the reaction was stirred for 6-10 hours. After the reaction was completed, the temperature was lowered to room temperature, and then purified water was added thereto, and then the mixture was stirred and allowed to stand to separate into layers, and then the layers were separated, and then column chromatography was performed to obtain intermediate I-1-1.

[0051] (2) Intermediate I-1-1 (1 eq), bromoethane (1.5-2.5 eq), and a hydroxide such as sodium hydroxide (3-7 eq) were sequentially added to a reaction vessel, and then an amide solvent such as DMF was added thereto, and then the reaction was stirred at 20-35°C for 8-12 hours under inert gas protection. After the reaction was completed, purified water was added thereto, and then the mixture was stirred and allowed to stand to separate into layers, and then the layers were separated, and then column chromatography was performed to obtain intermediate I-1-2.

[0052] (3) Intermediate I-1-2 (1 eq) was added to a mixed solvent of tetrahydrofuran and acetic acid (v:v=1:1), and then an oxidizing agent such as hydrogen peroxide aqueous solution (0.8-1.2 eq) was slowly added dropwise, and then the reaction was performed at 20-30°C for 8-14 hours under nitrogen protection. After the reaction was completed, purified water was added thereto, and then the mixture was stirred and allowed to stand to separate into layers, and then the layers were separated, and then column chromatography was performed to obtain intermediate I-1-3.

[0053] (4) Intermediate I-1-3 (1 eq) and phosphorus pentoxide (1.5-2.5 eq) were added to a reaction vessel, and then a solvent such as trifluoromethylsulfonic acid was added thereto, and then the reaction was stirred at 20-30°C under inert gas protection, and then the reaction solution was slowly poured into ice water after the reaction was completed, and then the filter cake was washed with deionized water after filtration. The filter cake was transferred to a pyridine solvent, and then the temperature was raised to 100-140°C under inert gas protection, and then the reaction was stirred for 8-14 hours, and then the reaction solution was poured into ice water to quench, and then hydrochloric acid was added. The product was extracted with dichloromethane, and then column chromatography was performed to obtain intermediate I-1-4.

[0054] (5) Intermediate I-1-4 (1 eq), bis(pinacolato)diboron (1.2-1.8 eq), potassium acetate (1.5-2.5 eq) were added into the reactor, purged with inert gas for three times, solvent such as 1,4-dioxane was added and purged with nitrogen for three times, then catalyst such as Pd2(dba)3 (0.008-0.012 eq) and X-phos (0.05-0.12 eq) was added, purged with nitrogen for three times, and heated to 80-120 °C under inert gas protection; after the reaction was completed, the mixture was cooled to room temperature, then the solvent was removed under reduced pressure, and the crude product was purified by column chromatography to obtain intermediate I-1-5.

[0055] (6) Intermediate I-1-5 (1 eq), reactant 3 (1-1.5 eq), a basic substance such as potassium carbonate (1.5-2.5 eq) were added into the reactor, purged with inert gas for three times, a mixture of water and tetrahydrofuran was added as a solvent and purged with inert gas for three times, then catalyst such as Pd(Ph3)4 (0.008-0.012 eq) was added, purged with nitrogen for three times, and heated to 75-100 °C under inert gas protection; after the reaction was completed, the mixture was cooled to room temperature, then the solvent was removed under reduced pressure, and the crude product was purified by column chromatography to obtain the final product I-1.

[0056] Hal, Hal1in synthesis route (1) are each independently selected from Cl or Br, and are not simultaneously present in the synthesis process.

[0057] (2) Synthesis route 2:

[0058] The specific process is as follows:

[0059] (1) Reactant 4 (1 eq), reactant 5 (1-1.5 eq), sodium alcohol such as sodium tert-butoxide (1.5-2.5 eq) were sequentially added to the reaction container, then a reaction solvent such as toluene was added, a catalyst such as tris(dibenzylideneacetone)dipalladium (0.03-0.07 eq) and bis(2-diphenylphosphinophenyl)ether (0.03-0.07 eq) was added under the protection of inert gas such as nitrogen, and the temperature was raised to 40-70 °C for stirring reaction for 6-10 hours. After the reaction was completed, it was cooled to room temperature, pure water was added, stirred and separated, the liquid was separated by column chromatography to obtain intermediate I-2-1.

[0060] (2) Intermediate I-2-1 (1 eq), a hydroxide such as potassium hydroxide (1.2-1.7 eq) were sequentially added to the reaction container, then a solvent DMSO was added, and the temperature was raised to 100-140 °C under inert gas for stirring reaction for 6-10 hours. After the reaction was completed, it was cooled to room temperature, pure water was added, extracted with dichloromethane, the liquid was separated by column chromatography to obtain intermediate I-2-2.

[0061] (3) Intermediate I-2-2 (1 eq), bis(pinacolato)diboron (1.2-1.8 eq), potassium acetate (1.5-2.5 eq) were added to the reactor, which was purged with inert gas three times, solvent such as 1,4-dioxane was added and purged with nitrogen three times, and catalyst such as Pd2(dba)3 (0.008-0.012 eq) and X-phos (0.05-0.12 eq) was added, which was purged with nitrogen three times, and then the temperature was raised to 80-120°C under nitrogen protection; after the reaction was completed, the mixture was cooled to room temperature, then the solvent was removed under reduced pressure, and the crude product was purified by column chromatography to obtain intermediate I-2-3.

[0062] (4) Intermediate I-2-3 (1 eq), reactant 3 (1 eq), potassium carbonate (2 eq) were added to the reactor, which was purged with nitrogen three times, a mixture of water and tetrahydrofuran was added as solvent and purged with nitrogen three times, and catalyst such as Pd(Ph3)4 (0.008-0.012 eq) was added, which was purged with nitrogen three times, and then the temperature was raised to 75-100°C under inert gas protection; after the reaction was completed, the mixture was cooled to room temperature, then the solvent was removed under reduced pressure, and the crude product was purified by column chromatography to obtain the final product I-2.

[0063] (3) Synthesis route 3:

[0064] The specific process is as follows:

[0065] (1) Reactant 6 (1 eq), reactant 7 (1-1.2 eq), sodium alcoholate such as sodium tert-butoxide (1.5-2.5 eq) were sequentially added to the reaction container, and then a reaction solvent such as toluene was added, catalyst such as Pd2(dba)3 (0.008-0.012 eq) and P(t-Bu)3 (0.015-0.025 eq) was added under the protection of inert gas such as nitrogen, and then the temperature was raised to 100-140°C under reflux, and then cooled to room temperature, and then pure water was added, stirred and separated after standing, and then column chromatography was performed to obtain intermediate I-3-1.

[0066] (2) Intermediate I-3-1 (1 eq), sulfur (1.5-2.5 eq), iodine (0.02-0.04 eq) were sequentially added to the reaction container, and then a solvent such as dichlorobenzene was added, and the temperature was raised to 140-180°C under the protection of inert gas such as nitrogen, and then stirred to react. Note that hydrogen sulfide gas is generated during the reaction, so the tail gas should be absorbed by saturated sodium hydroxide aqueous solution. After the reaction was completed, the mixture was cooled to room temperature. Then, the solvent was removed under reduced pressure, and the crude product was purified by column chromatography to obtain intermediate I-3-2.

[0067] (3) Intermediate I-3-2 (1 eq), brominated starting material (0.8-1.2 eq), sodium alkoxide such as sodium tert-butoxide (1.5-2.5 eq) are sequentially added to a reaction vessel, and a reaction solvent such as toluene is added thereto, a catalyst such as Pd2(dba)3 (0.008-0.012 eq) and P(t-Bu)3 (0.015-0.025 eq) are added thereto under protection of an inert gas such as nitrogen, and then the mixture is refluxed at 100-140°C under protection of an inert gas such as nitrogen, and then cooled, purified water is added thereto, and after stirring, the mixture is allowed to stand to separate into layers, and the separated layers are subjected to liquid-liquid separation, and then column chromatography to obtain intermediate I-3-3.

[0068] (4) Intermediate I-2-2 (1 eq), bis(pinacolato)diboron (1.2-1.8 eq), potassium acetate (1.5-2.5 eq) are added to a reaction vessel, and the vessel is subjected to three times of inert gas replacement, a solvent such as 1,4-dioxane is added and subjected to three times of nitrogen replacement, and then a catalyst such as Pd2(dba)3 (0.008-0.012 eq) and X-phos (0.05-0.12 eq) is added and subjected to three times of nitrogen replacement, and then the mixture is heated to 80-120°C under protection of an inert gas such as nitrogen, and then after completion of the reaction, the mixture is cooled to room temperature, and then the solvent is removed under reduced pressure, and the crude product is purified by column chromatography to obtain intermediate I-3-4.

[0069] (5) Intermediate I-3-4 (1 eq), reactant 3 (1-1.5 eq), a basic substance such as potassium carbonate (1.5-2.5 eq) are added to a reaction vessel, and the vessel is subjected to three times of inert gas replacement, a mixture of water and tetrahydrofuran is added as a solvent and subjected to three times of nitrogen replacement, and then a catalyst such as Pd(Ph3)4 (0.008-0.012 eq) is added and subjected to three times of nitrogen replacement, and then the mixture is heated to 75-100°C under protection of an inert gas such as nitrogen, and then after completion of the reaction, the mixture is cooled to room temperature, and then the solvent is removed under reduced pressure, and the crude product is purified by column chromatography to obtain final product I-3.

[0070] In a second aspect, an embodiment of the present application provides an organic electroluminescent material including a first host material and a second host material, the first host material being selected from the above-mentioned organic electroluminescent compound, and the second host material being selected from a compound represented by the following general formula (2):

[0071] Formula (2); the compound shown in Formula (1) and the compound shown in Formula (2) are combined as the host material for the organic electroluminescence device, which can effectively improve the luminous efficiency and service life of the organic electroluminescence device. Specifically, the first host material adopts a compound with triazine as the skeleton, the compound has a high glass transition temperature and molecular thermal stability, a suitable HOMO and LUMO energy level, and a high Eg, and is matched with a second host with a triarylamine structure to form a host material with enhanced hole transport and electron transport capacity, so that when the hole is injected into the p-type host and the electron is injected into the n-type host, the driving voltage of the organic electroluminescence device is reduced, and the service life and luminous efficiency are also enhanced.

[0072] Specifically, L3, L4 and L5 are each independently selected from any one of a bond, a substituted or unsubstituted C6-C30 aryl group, and a substituted or unsubstituted C6-C30 heteroaryl group;

[0073] Ar3, Ar4 and Ar5 are each independently selected from any one of a substituted or unsubstituted C6-C30 aryl group, a substituted or unsubstituted C6-C30 heteroaryl group, and a substituted or unsubstituted C10-C30 fused ring group; wherein the heteroaryl group includes a monocyclic aromatic group containing at least one heteroatom or a polycyclic aromatic system containing at least one heteroatom, and the heteroatom includes any one of O, S and N.

[0074] Further, Ar3 is independently selected from a substituted or unsubstituted C6-C36 aryl group or a substituted or unsubstituted C3-C30 heteroaryl group, the heteroaryl group includes a monocyclic aromatic group containing at least one heteroatom or a polycyclic aromatic system containing at least one heteroatom, and the heteroatom includes any one of O, S and N; and the substituents in the C6-C36 aryl group and the C3-C30 heteroaryl group include at least one of a deuterium, a cyano group and a functional group formed by one or more methyl groups.

[0075] Further, Ar4 and Ar5 are each independently selected from any one of the groups shown in the following structural formula:

[0076] .

[0077] It should be noted that: (1) the above groups can be connected at any substitutable site;

[0078] (2) the hydrogen in the above groups can be further selectively substituted by deuterium.

[0079] Further, L3 is selected from any one of a bond, unsubstituted C6-C18 aryl and substituted or unsubstituted C6-C18 heteroaryl, wherein the heteroatom is selected from any one of O, S and N; L4 and L5 are each independently selected from any one of a bond, phenyl and naphthyl.

[0080] It should be noted that the above "substituted" means substituted by one or at least two substituents selected from deuterium, cyano, methyl, C6-C24 aryl and C6-C24 heteroaryl, wherein the heteroatom is selected from O, S and N.

[0081] The second host material is selected from any one of the compounds shown in the following structural formula:

[0082]

[0083]

[0084]

[0085] .

[0086] The above compounds are only examples of some of the compounds of the preferred general formula (2) of the present application, and the compounds shown in general formula (2) are not limited to the above, and any compound which is a simple transformation of the groups L1 to L3 and Ar1 to Ar3 within the ranges defined above based on the structure shown in general formula (2) should be included.

[0087] Further, the mass ratio of the first host material to the second host material is 1:9-9:1.

[0088] The present application also provides a preparation method of the compound shown in general formula (2) above, which comprises synthesizing according to the following synthesis route:

[0089] The specific process is as follows:

[0090] (1) The reactant 8 (1 eq), the reactant 9 (1-1.5 eq), sodium alcohol such as sodium tert-butoxide (1.5-2.5 eq) are sequentially added into a reaction container, then a reaction solvent such as toluene is added, a catalyst such as Pd2(dba)3 (0.008-0.012 eq) and P(t-Bu)3 (0.015-0.025 eq) are added under the protection of inert gas such as nitrogen, then refluxing is carried out at 100-140°C under the protection of inert gas such as nitrogen, then cooling is carried out to room temperature, pure water is added, after stirring, standing and layer separation, column chromatography is carried out, to obtain the intermediate 2-1.

[0091] (2) The synthesis method of the compound represented by general formula 2 using the intermediate 2-1 is the same as the synthesis method of the intermediate 2-1, which will not be described in detail here.

[0092] In the third aspect, the organic electroluminescence device provided by the embodiment of the present application comprises 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 which are sequentially arranged; the material forming the light-emitting layer comprises the double-host-containing organic electroluminescence material described in the foregoing embodiments, and further comprises a doping material.

[0093] In the embodiment of the present application, the mass ratio of the double-host-containing organic electroluminescence material to the doping material in the light-emitting layer is (5-199):1; preferably (5-100):1, and more preferably (5-15):1.

[0094] In the embodiment of the present application, the preparation method of the light-emitting layer includes but is not limited to forming the light-emitting layer by a solution coating method and a vacuum deposition method; here, the solution coating method means spin coating, dip coating, inkjet printing, screen printing, spraying and the like, but is not limited thereto.

[0095] In the embodiment of the present application, the first electrode is an anode.

[0096] As an anode material, a material with a large work function is preferred in order to enable the hole to be smoothly injected into the organic layer. The anode material that can be used in the embodiment of the present application 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 a metal and an oxide such as ZnO / Al or SnO2 / Sb; a conductive polymer such as poly(3-methylthiophene), polypyrrole or polyaniline; but is not limited thereto. In the embodiment of the present application, the anode is an ITO anode.

[0097] In the embodiments of the present application, the material forming the hole injection layer is selected from one or more of metalloporphyrin, oligothiophene, arylamine-based organic material, benzonitrile-based organic material, quinacridone-based organic material, polyaniline-based and polythiophene-based conductive polymer.

[0098] The material forming the hole injection layer receives holes from the anode at a low voltage, and the highest occupied molecular orbital (HOMO) of the material of the hole injection layer is preferably between the work function of the anode material and the HOMO of the surrounding organic material layer.

[0099] In the embodiments of the present application, the material forming the hole transport layer is selected from one or more of arylamine-based organic material, conductive polymer, block copolymer having both conjugated and non-conjugated portions. The material of the hole transport layer is capable of receiving holes from the anode or the hole injection layer and transporting the holes to the light emitting layer, having a high hole mobility.

[0100] In the embodiments of the present application, the electron transport layer is selected from one or more of 8-hydroxyquinoline Al complex, organic radical compound, but is not limited thereto.

[0101] In the embodiments of the present application, the thickness of the electron transport layer is 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, or 50 nm, or any value between 1 nm and 50 nm.

[0102] The electron transport layer can prevent a decrease in electron transport characteristics, prevent an increase in driving voltage due to the electron transport layer being too thick, and function to promote electron transport. The material of the electron transport layer is used to receive electrons from the cathode and transport the electrons to the light emitting layer, having a high electron mobility.

[0103] In the embodiments of the present application, the material forming the electron injection layer is selected from one or more of fluorenone, anthraquinone dimethane, diphenylquinone, thiopyran dioxide, imidazole, perylene tetracarboxylic acid, fluorenylidene methane, anthrone or its derivative, metal complex, nitrogen-containing five-membered ring derivative, but is not limited thereto.

[0104] The electron injection layer can function to promote electron injection, and the electron injection material preferably has the ability to transport 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 in addition thereto, has an excellent film formation ability.

[0105] In the embodiments of the present application, the second electrode is a cathode.

[0106] As the cathode material, in order to make the electron easily inject into the organic layer, a material with a small work function is preferred. Specific examples of the cathode material include: metals such as magnesium, calcium, sodium, potassium, titanium, indium, yttrium, lithium, gadolinium, aluminum, silver, tin, lead, and other metals or alloys thereof; multi-layer structure materials such as LiF / Al or LiO2 / Al; but not limited thereto. In some embodiments of the present application, the cathode material is Al.

[0107] In embodiments of the present application, the organic electroluminescent device can be a top emission type, a bottom emission type, or a double-sided emission type.

[0108] The numerical ranges recited herein include all values from and including the lower and upper values. This is expressly stated on behalf of Applicants to avoid discovery of a de minimus amount of experimentation such as is required by the expression "from about 'x' to 'y'." It is appropriate to group the upper and lower limit of a range as the numerical limits of a range are inherently inclusive.

[0109] It should be noted that the numerical values given in the following examples are as accurate as possible, but the person skilled in the art understands that due to unavoidable measurement errors and experimental operation problems, each number should be understood as an approximate number, rather than an absolutely accurate number.

[0110] Reference is made to the following well-known knowledge:

[0111] Transition Metal Organometallic Chemistry (6th Edition), Robert H. Crabtree, Publisher: Shanghai East China University of Technology Press, Publication Time: 2017-09-00, ISBN: 978-7-5628-5111-0, Page 388.

[0112] Organic Chemistry and Optoelectronic Material Experiment Tutorial, Chen Runfeng, Publisher: Southeast University Press, Publication Time: 2019-11-00, ISBN: 9787564184230, Page 174.

[0113] The features and properties of the present application are further described in detail below in conjunction with the embodiments.

[0114] Example 1

[0115] A preparation method of an organic electroluminescent compound (number H1-2) according to an embodiment of the present application comprises: synthesizing according to the following synthesis path:

[0116] The specific process is as follows:

[0117] (1) Benzene-1,2-dithiol (1 eq), 7-chloro-1-iodonaphthalene (1 eq), sodium tert-butoxide (2 eq) were added into a reaction vessel successively, and toluene was added as a reaction solvent. A catalyst, tris(dibenzylideneacetone)dipalladium (0.05 eq), bis(2-diphenylphosphinophenyl)ether (0.05 eq) was added under nitrogen protection, and the mixture was stirred at 50°C for 8 hours. After the reaction was completed, the mixture was cooled to 25°C. Purified water was added, and the mixture was stirred for 30 minutes. After standing and separating the layers, the mixture was subjected to column chromatography to obtain intermediate H1-2-1 (yield: 61%).

[0118] (2) Intermediate H1-2-1 (1 eq), bromoethane (2 eq), sodium hydroxide (5 eq) were added into a reaction vessel successively, and DMF was added as a reaction solvent. The mixture was stirred at 25°C for 12 hours. After the reaction was completed, purified water was added, and the mixture was stirred for 30 minutes. After standing and separating the layers, the mixture was subjected to column chromatography to obtain intermediate H1-2-2 (yield: 58%).

[0119] (3) Intermediate H1-2-2 (1 eq) was added to a mixed solvent of tetrahydrofuran and acetic acid (v:v = 1:1), and hydrogen peroxide aqueous solution (1 eq) was slowly added dropwise. The mixture was stirred at 25°C under nitrogen protection for 12 hours. After the reaction was completed, purified water was added, and the mixture was stirred for 30 minutes. After standing and separating the layers, the mixture was subjected to column chromatography to obtain intermediate H1-2-3 (yield: 65%).

[0120] (4) Intermediate H1-2-3 (1 eq), phosphorus pentoxide (2 eq) were added into a reaction vessel, and trifluoromethylsulfonic acid was added as a reaction solvent. The mixture was stirred at 25°C under nitrogen protection for 24 hours. After the reaction was completed, the reaction solution was slowly poured into ice water, and the filter cake was washed with deionized water. The filter cake was transferred to a pyridine solvent, and the mixture was stirred at 120°C under nitrogen protection for 12 hours. After the reaction was completed, the reaction solution was poured into ice water, and hydrochloric acid was added. The product was extracted with dichloromethane, and subjected to column chromatography to obtain intermediate H1-2-4 (yield: 57%).

[0121] (5) Intermediate H1-2-4 (1 eq), pinacol diboron (1.5 eq), potassium acetate (2 eq) were added into a reactor, and the mixture was subjected to nitrogen replacement three times. 1,4-Dioxane was added as a solvent and subjected to nitrogen replacement three times. Pd2(dba)3 (0.01 eq) and X-phos (0.08 eq) were added, and the mixture was subjected to nitrogen replacement three times. The mixture was heated to 100°C under nitrogen protection for 12 hours. After the reaction was completed, the mixture was cooled to room temperature. Subsequently, the solvent was removed under reduced pressure, and the crude product was purified by column chromatography to obtain intermediate H1-2-5 (yield: 80%).

[0122] (6) Intermediate H1-2-5 (1 eq), 2-chloro-4-(dibenzo[b,d]furan-1-yl)-6-phenyl-1,3,5-triazine (1 eq), potassium carbonate (2 eq) were added to a reactor, which was purged with nitrogen three times, and a mixture of water and tetrahydrofuran was added as a solvent and purged with nitrogen three times, then Pd(Ph3)4 (0.01 eq) was added and purged with nitrogen three times, and the temperature was raised to 80°C under nitrogen protection for 12 hours. After the reaction was completed, the mixture was cooled to room temperature, then the solvent was removed under reduced pressure, and the crude product was purified by column chromatography to obtain the final product H1-2 (yield 70%, HPLC > 99%, mass spectrometry test value 587.35), and the nuclear magnetic spectrum is shown in Figure 1 .

[0123] Example 2

[0124] The preparation method of the organic electroluminescent compound (number H1-122) according to the embodiment of the application comprises: synthesizing according to the following synthesis path:

[0125] The specific process is as follows:

[0126] (1) Aniline (1 eq), 3-bromo-6-chlorophenanthrene (1 eq), and sodium tert-butoxide (2 eq) were sequentially added to a reaction container, and toluene was added as a reaction solvent. A catalyst Pd2(dba)3 (0.01 eq) and P(t-Bu)3 (0.02 eq) were added under nitrogen protection, and the temperature was raised to 120°C under nitrogen protection for 24 hours. Then the temperature was cooled to 25°C, pure water was added, stirred for 30 minutes, and then separated by layering. The product was obtained by column chromatography, and the yield was 83%.

[0127] (2) Intermediate I-3-1 (1 eq), elemental sulfur (2 eq), and elemental iodine (0.03 eq) were sequentially added to a reaction container, and dichlorobenzene was added as a reaction solvent. The temperature was raised to 160°C under nitrogen protection, and the reaction was stirred for 4 hours. Note that hydrogen sulfide gas is generated during the reaction, so the tail gas should be absorbed by saturated sodium hydroxide aqueous solution. After the reaction was completed, the mixture was cooled to room temperature. Then, the solvent was removed under reduced pressure, and the crude product was purified by column chromatography to obtain intermediate H1-122-2 (yield 75%).

[0128] (3) Intermediate H1-122-2 (1 eq), bromobenzene (1 eq), sodium tert-butoxide (2 eq) were added into the reaction vessel in turn, 150 mL of toluene was added as the reaction solvent, catalyst Pd2(dba)3 (0.01 eq) and P(t-Bu)3 (0.02 eq) were added under nitrogen protection, and the mixture was refluxed at 120°C for 24 hours under nitrogen protection, then cooled to 25°C, pure water was added, stirred for 30 minutes, and then separated into two layers after standing, and column chromatography was performed to obtain intermediate H1-122-3 (yield 81%).

[0129] (4) Intermediate H1-122-3 (1 eq), pinacol diboronic acid (1.5 eq), potassium acetate (2 eq) were added into the reactor, and nitrogen was replaced three times, 1,4-dioxane was added as the solvent and nitrogen was replaced three times, Pd2(dba)3 (0.01 eq) and X-phos (0.08 eq) were added, and nitrogen was replaced three times, and the mixture was heated to 100°C for 12 hours under nitrogen protection; after the reaction was completed, the mixture was cooled to room temperature, then the solvent was removed under reduced pressure, and the crude product was purified by column chromatography to obtain intermediate H1-122-4 (yield 79%).

[0130] (5) Intermediate H1-122-4 (1 eq), 2-chloro-4,6-diphenyl-1,3,5-triazine (1 eq), potassium carbonate (2 eq) were added into the reactor, and nitrogen was replaced three times, a mixture of water and tetrahydrofuran was added as the solvent and nitrogen was replaced three times, Pd(Ph3)4 (0.01 eq) was added, and nitrogen was replaced three times, and the mixture was heated to 80°C for 12 hours under nitrogen protection; after the reaction was completed, the mixture was cooled to room temperature, then the solvent was removed under reduced pressure, and the crude product was purified by column chromatography to obtain the final product H1-122 (yield 75%, HPLC > 99%, mass spectrometry test value 606.97).

[0131] Example 3

[0132] The preparation method of a second host material (number H2-10) according to an embodiment of the present application comprises: synthesizing according to the following synthesis path:

[0133] The specific process is as follows:

[0134] Take N- (phenyl-d5) naphthalene-2-amine (1 eq), 9-chloro-2-phenylphenanthro [3, 4-d] oxazole (1 eq), sodium tert-butoxide (2 eq) in a reaction bottle, add toluene, add catalyst Pd2 (dba) 3 (0.01 eq) and P (t-Bu) 3 (0.02 eq) under nitrogen protection, reflux at 120℃ for 24 hours under nitrogen protection, then cool to 25℃, add pure water to it, stir for 30 minutes, then stand and separate, separate, column chromatography, to obtain product H2-10 (yield 73%, HPLC > 99%, mass spectrometry test value 517.87).

[0135] Example 4

[0136] The preparation method of a second host material (No. H2-203) according to an embodiment of the present application comprises: synthesizing according to the following synthesis path:

[0137] Specifically as follows:

[0138] Take N- (phenyl-d5) naphthalene-2-amine (1 eq), 9-chloro-2-phenylphenanthro [3, 4-d] oxazole (1 eq), sodium tert-butoxide (2 eq) in a reaction bottle, add toluene, add catalyst Pd2 (dba) 3 (0.01 eq) and P (t-Bu) 3 (0.02 eq) under nitrogen protection, reflux at 120℃ for 24 hours under nitrogen protection, then cool to 25℃, add pure water to it, stir for 30 minutes, then stand and separate, separate, column chromatography, to obtain product H2-10 (yield 73%, HPLC > 99%, mass spectrometry test value 517.87).

[0139] Device examples 1-36 and related comparative examples

[0140] The device examples and comparative examples described above respectively provide a preparation method of an organic electroluminescent device, comprising:

[0141] (1) The ITO (indium tin oxide) glass substrate with a thickness of 1500 angstroms is cleaned in distilled water for 2 times, ultrasonic washing for 30 minutes, and then repeatedly cleaned with distilled water for 2 times, ultrasonic washing for 10 minutes. After washing, ultrasonic washing is carried out with methanol, acetone and isopropanol in sequence (5 minutes for each washing), drying, and then transferring to a plasma cleaning machine for washing for 5 minutes to obtain an ITO anode.

[0142] (2) In the evaporation machine, the surface of the ITO anode obtained in step (1) is vacuum evaporated with HIL, and the thickness is 700 angstroms to obtain a hole injection layer, and the structure of HIL is as follows.

[0143] (3) Vacuum deposition of HTL on the surface of the hole injection layer obtained in step (2) to form a hole transport layer, with a thickness of 800 angstroms. The structure of the HTL is as follows.

[0144] (4) Vacuum deposition of a light-emitting layer material on the surface of the hole transport layer, linear gradient co-deposition by means of multi-source co-deposition, with a thickness of 300 angstroms, to obtain a light-emitting layer. The light-emitting layer material comprises a dual-host material and a dopant 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 and the dopant material is 10:1. The dual-host material is provided by device embodiments 1-36, comparative examples 1-18, and parallel comparative examples 1-6; the structure of the dopant material Dopant is as follows.

[0145] (5) Vacuum deposition of HBL on the surface of the light-emitting layer obtained in step (4) to form a hole blocking layer, with a thickness of 100 angstroms. The structure of the HBL is as follows.

[0146] (6) Vacuum deposition of ETL on the surface of the hole blocking layer obtained in step (5) to obtain an electron transport layer, with a thickness of 300 angstroms. The structure of the ETL is as follows.

[0147] (7) Vacuum deposition of Liq on the surface of the electron transport layer obtained in step (6) to obtain an electron injection layer, with a thickness of 15 angstroms. The structure of the EIL is as follows.

[0148] (8) Vacuum deposition of 1200 angstroms of Al on the surface of the electron injection layer obtained in step (7) to form a cathode, thereby obtaining the organic electroluminescent device.

[0149] The structures of the materials used in each functional layer of the organic electroluminescent device are as follows:

[0150]

[0151] Specifically, device embodiments 1-36 use the dual-host material provided by the embodiments of the present application, and the collocation of the dual-host material is shown in Table 2. For the scheme in which the dual-host material comprises a first host compound and a second host compound, the mass ratio of the first host compound and the second host compound is 60:40.

[0152] Comparative examples 1-18 use one or two compounds with the structures shown in Table 1 as host materials.

[0153] Parallel comparative examples 1-6 use one host material compound with the structure shown in general formula (1) or general formula (2) of the present application and one compound with the structure shown in Table 1 to be collocated.

[0154] In Table 2, "-" indicates that the compound is not contained in the host material; the structures of E and F are shown below, respectively.

[0155] Table 1 Compounds of host materials used in the comparative examples

[0156]

[0157] Test

[0158] The driving voltage, luminous efficiency, and time taken for the luminance to decrease from 100% to 95% (lifetime; T95) of the tested organic electroluminescent device at a luminance of 15000 nits were tested, and the test results are shown in Table 2.

[0159] Table 2 Test results

[0160]

[0161] According to Table 2, it can be seen from device examples 1-36 that when the host material of the light-emitting layer is compounded with the compound of the first host material and the compound of the second host material provided in the examples of the present application, the luminous efficiency and service life of the device can be greatly improved.

[0162] It can be seen from the comparison of comparative examples 1-14 and comparative examples 15-18 that the use of only one of them will result in a significant decrease in the luminous efficiency of the device, a significant shortening of the service life, and an increase in the voltage.

[0163] It can be seen from the comparison of the performance of the devices prepared from device examples 1-36 and parallel comparative examples 1-6 that the organic electroluminescent device prepared from parallel comparative examples 1-6 has an efficiency of 34.7-36.2 cd / A, a driving voltage of 3.41-3.54 V, and a lifetime of 472-479 h; the organic electroluminescent device prepared from device examples 1-36 provided in the examples of the present application has a luminous efficiency of 42.3-44.8 cd / A, which is significantly higher than that of the device in parallel comparative examples 1-6; the driving voltage of the device examples 1-36 of the present application is 3.10-3.28 V, which is significantly lower than that of the device in parallel comparative examples 1-6; and the lifetime of the device in device examples 1-36 of the present application is 589-615 h, which is much higher than that of the device in parallel comparative examples 1-6.

[0164] In summary, the organic electroluminescent compound provided in this invention has a sulfur four-membered fused ring structure as its parent structure, with a triazine group attached to the parent core. This parent core structure containing the sulfur four-membered fused ring exhibits strong molecular rigidity, which is beneficial for improving the molecular thermal stability. The attachment of the triazine group to the parent core introduces a certain degree of spatial distortion, which is beneficial for increasing the molecular energy level and band gap, while also helping to suppress molecular aggregation. When the organic compound provided in this invention is used as an electron transport host material in a hybrid host material, the large fused ring structure enhances conjugation and carrier transport performance, thus improving the performance of organic electroluminescent devices.

[0165] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An organic electroluminescent compound, characterized by The organic electroluminescent compound is selected from any one of the compounds represented by the following general formula (1-1) to general formula (1-3): A is selected from phenyl or naphthyl, and A is fused with the adjacent phenyl ring; L1and L2are each independently selected from a bond; R1is independently selected from any one of hydrogen, phenyl, biphenyl and naphthyl; Ar1and Ar2are each independently selected from any one of substituted or unsubstituted C6-C30aryl, substituted or unsubstituted C6-C30heteroaryl and substituted or unsubstituted C10-C30fused ring group; wherein the heteroaryl includes a monocyclic aromatic group containing at least one heteroatom or a polycyclic aromatic system containing at least one heteroatom, and the heteroatom is any one of O, S, N, P and Si; "substituted" means substituted with one or at least two groups selected from deuterium, cyano, methyl, C6-C24aryl and C6-C24heteroaryl, wherein the heteroatom is selected from O, S, N; All hydrogens in the compounds represented by general formula (I-1) to (I-3) are independently selected from protium or deuterium.

2. The organic electroluminescent compound according to claim 1, wherein, R1is selected from any one of hydrogen, phenyl, biphenyl and naphthyl; Ar1and Ar2are each independently selected from any one of the groups represented by the following structural formula: 。 3. An organic electroluminescent compound, characterized by The organic electroluminescent compound is selected from any one of the compounds represented by the following general formula (1-1) to general formula (1-3): 。 4. An organic electroluminescent material, characterized in that, It comprises a first host material and a second host material, the first host material is selected from the organic electroluminescent compound of claim 1, and the second host material is selected from the compound represented by the following general formula (2): Formula (2); wherein L3, L4and L5are each independently selected from a bond, substituted or unsubstituted C6-C30aryl and substituted or unsubstituted C6-C30heteroaryl; Ar3is independently selected from substituted or unsubstituted C6-C36aryl or substituted or unsubstituted C3-C30heteroaryl, and the heteroaryl includes a monocyclic aromatic group containing at least one heteroatom or a polycyclic aromatic system containing at least one heteroatom, and the heteroatom includes any one of O, S and N; Ar4and Ar5are each independently selected from any one of substituted or unsubstituted C6-C30aryl, substituted or unsubstituted C6-C30heteroaryl and substituted or unsubstituted C10-C30fused ring group; wherein the heteroaryl includes a monocyclic aromatic group containing at least one heteroatom or a polycyclic aromatic system containing at least one heteroatom, and the heteroatom includes any one of O, S and N; "substituted" means substituted with one or at least two groups selected from deuterium, cyano, methyl, C6-C24aryl and C6-C24heteroaryl, wherein the heteroatom is selected from O, S, N.

5. The organic electroluminescent material according to claim 4, wherein, Ar4and Ar5are each independently selected from any one of the groups represented by the following structural formula: ； L3is selected from the group consisting of a direct bond, an unsubstituted C6-C18aryl group, and a substituted or unsubstituted C6-C18heteroaryl group, wherein the heteroatom is selected from the group consisting of O, S, and N; L4and L5are each independently selected from the group consisting of a direct bond, a phenyl group, and a naphthyl group; "substituted" means substituted with one or at least two groups selected from the group consisting of deuterium, cyano, methyl, C6-C24aryl, and C6-C24heteroaryl, wherein the heteroatom is selected from the group consisting of O, S, and N.

6. The organic electroluminescent material according to claim 5, characterized in that The second host material is selected from any one of the compounds represented by the following structural formula: 。 7. The organic electroluminescent material according to claim 5, characterized in that The mass ratio of the first host material to the second host material is 1:9-9:

1.

8. An organic electroluminescent device, characterized by An organic electroluminescence device comprising the light-emitting layer according to any one of claims 4 to 7.

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