Organic electroluminescent compound, organic electroluminescent material containing double hosts and luminescent device

Abstract

The invention belongs to the field of organic electroluminescent materials, and discloses an organic electroluminescent compound, an organic electroluminescent material containing double hosts and a luminescent device. The double-host-containing organic electroluminescent material comprises a first host material and a second host material, the first host material is a compound having a structure represented by a general formula (1), the second host material is a compound having a structure represented by a general formula (2), and the compounds are specifically combined as the host material to be used in an organic electroluminescent device. And the luminous efficiency and the service life of the device can be effectively improved.

Description

Technical Field

[0001] The present invention belongs to the field of organic electroluminescent materials, and particularly relates to an organic electroluminescent compound, an organic electroluminescent material containing a double host, and a light-emitting device. Background Art

[0002] Organic electroluminescent devices are self-luminous devices. Due to their characteristics such as low driving voltage, high resolution, high brightness, fast response time, and flexibility, and low raw material production cost, easy processing, and high purity, they have received extensive attention in the panel display device industry.

[0003] Currently, OLED display technology has been applied in fields such as smart phones and tablet computers, and will also expand to large-size application fields such as televisions. However, compared with the actual product application requirements, the performance of OLEDs such as luminous efficiency and service life still needs to be further improved.

[0004] The light-emitting material of an organic electroluminescent device (OLED) is the most important factor determining the luminous efficiency of the device, and can be classified into a host material and a doping material in terms of function. The light-emitting material can be used by mixing the host and the dopant to improve color purity, luminous efficiency, and stability. Devices with excellent electroluminescence (EL) characteristics usually have a structure of a light-emitting layer formed by doping a dopant into a host. When using such a dopant / host material system as the light-emitting material, since the host material greatly affects the efficiency and life of the light-emitting device, it is crucial to select a suitable host material.

[0005] Therefore, the current urgent task is to develop OLEDs with high efficiency and long life characteristics. Especially considering the EL characteristics required for medium and large OLED panels, it is urgent to develop light-emitting materials that are superior to conventional light-emitting materials and have excellent performance. Summary of the Invention

[0006] In view of this, aiming at the deficiencies of the prior art, the present invention discloses and provides an organic electroluminescent compound, an organic electroluminescent material containing a double host, and a light-emitting device.

[0007] In order to achieve the above object, the following technical solutions are adopted:

[0008] An organic electroluminescent compound, wherein the organic electroluminescent compound is a first host compound having a structure represented by the general formula (1):

[0009]

[0010] Wherein, L 1 、L 2 are each independently selected from a linking bond, a substituted or unsubstituted (C 6 -C30 ) aryl, substituted or unsubstituted (C 6 -C 30 ) heteroaryl;

[0011] Ar 1 、Ar 2 are each independently selected from substituted or unsubstituted (C 6 -C 30 ) aryl, substituted or unsubstituted (C 6 -C 30 ) heteroaryl, substituted or unsubstituted (C 10 -C 30 ) fused ring group; wherein, heteroaryl includes a monocyclic aromatic group or a polycyclic aromatic system containing at least one heteroatom, and heteroatoms include but are not limited to O, S, N.

[0012] Furthermore, the compound of formula (1) has the compound structures shown in I-1 to I-4:

[0013]

[0014] Furthermore, Ar 1 、Ar 2 are each independently selected from substituted or unsubstituted phenyl, naphthyl, biphenyl, benzodimethylfluorenyl, benzofuranyl, benzothiophenyl, phenanthrene, benzodiphenylfluorenyl, tert-butylphenyl, cyanophenyl; L 1 and L 2 are each independently selected from a linking bond.

[0015] Furthermore, the above-mentioned "substitution" is selected from deuterium, cyano, methyl, C 6 -C 24 aryl, C 6 -C 24 heteroaryl, wherein the heteroatom is selected from O, S, N.

[0016] In the present invention, the organic electroluminescent compound has any one of the following structures, but is not limited thereto:

[0017]

[0018]

[0019]

[0020]

[0021]

[0022]

[0023]

[0024]

[0025]

[0026]

[0027]

[0028]

[0029]

[0030]

[0031] The above are some specific structural forms of the host material, but not limited to the listed chemical structures. All compounds with simple transformations of groups within the defined scope based on the structural general formula shown in Formula (1) should be included.

[0032] The second object of the present invention is to provide an organic electroluminescent material containing a double host. The organic electroluminescent material containing a double host includes a first host material and a second host material, and the mass ratio of the first host material to the second host material is 1:9 - 9:1; the first host material has at least one of the organic electroluminescent compounds shown in the general formula (1), and the second host material has the structure shown in the general formula (2):

[0033]

[0034] Among them, L 1 to L 3 are each independently selected from a linking bond, a substituted or unsubstituted (C 6 - C 30 ) aryl group, or a substituted or unsubstituted (C 6 - C 30 ) heteroaryl group;

[0035] Ar 1 to Ar 3 are each independently selected from a substituted or unsubstituted (C 6 - C 30 ) aryl group, a substituted or unsubstituted (C 6 - C 30 ) heteroaryl group, a substituted or unsubstituted (C 10 - C 30a fused ring group; wherein the heteroaryl is a monocyclic aromatic group or a polycyclic aromatic system containing at least one heteroatom, and the heteroatoms include, but are not limited to, O, S, and N.

[0036] Further, Ar 1 is selected from C 6 -C 36 aryl, substituted or unsubstituted C 3 -C 30 heteroaryl, and the heteroaryl is a monocyclic aromatic group or a polycyclic aromatic system containing at least one heteroatom, and the heteroatoms include, but are not limited to, O, S, and N;

[0037] Ar 2 and Ar 3 are each independently selected from substituted or unsubstituted phenyl, biphenyl, and terphenyl;

[0038] L 2 and L 3 are each independently selected from a linking bond;

[0039] L 1 is selected from a linking bond, unsubstituted C 6 -C 18 aryl, substituted or unsubstituted C 6 -C 18 heteroaryl, wherein the heteroatom is selected from O, S, and N;

[0040] The "substitution" is selected from deuterium, cyano, methyl, C 6 -C 24 aryl, C 6 -C 24 heteroaryl, wherein the heteroatom is selected from O, S, and N.

[0041] In the present invention, the second host material has any one of the following structures, but is not limited thereto:

[0042]

[0043]

[0044]

[0045]

[0046]

[0047]

[0048]

[0049]

[0050]

[0051]

[0052]

[0053] The above is the specific structural formula of the second host material. The present invention preferably adopts the above structure but is not limited thereto. Any compound based on the structure shown in the general formula (2), where L 1 to L 3 and Ar 1 to Ar 3 groups are simple transformations of all groups within the previously defined ranges should be included.

[0054] The present invention also provides a preparation method of an organic electroluminescent material containing a double host, specifically including the preparation methods of the first host material and the second host material, and the specific steps are as follows:

[0055] 1. The synthesis methods of the general formulas I-1 and I-2 of the first host material are as follows:

[0056] (1) Add 2-bromochloronaphthol (1 eq), bis(pinacolato)diboron (1.5 eq), and potassium acetate (2 eq) to the reactor, displace with nitrogen three times, add 1,4-dioxane as the solvent and displace with nitrogen three times, and then add Pd 2 (dba) 3 (0.01 eq) and X-phos (0.08 eq), displace with nitrogen three times, and heat to 100 °C under nitrogen protection for reaction for 12 hours; after the reaction is completed, cool the mixture to room temperature, then, remove the solvent under reduced pressure, and purify the crude product by column chromatography to obtain intermediates I-a-1 and I-a-2.

[0057] (2) Add the intermediate I-a-1 series (1 eq), 2-bromo-3-fluorobenzaldehyde (1 eq), and potassium carbonate (2 eq) to the reactor, displace with nitrogen three times, add a mixture of water and tetrahydrofuran as the solvent and displace with nitrogen three times, and then add Pd(Ph 3 ) 4 (0.01 eq), displace with nitrogen three times, and heat to 80 °C under nitrogen protection for reaction for 12 hours; after the reaction is completed, cool the mixture to room temperature, then, remove the solvent under reduced pressure, and purify the crude product by column chromatography to obtain intermediates I-b-1 and I-b-2.

[0058] (3) Add the intermediate I-b-1 series (1 eq) and potassium carbonate (3 eq) to the reactor, displace the air with nitrogen three times, add DMAc as the solvent, displace the air with nitrogen three times again, stir and heat up to 170 °C for reaction for 9 hours. After the reaction is completed, cool to room temperature. Subsequently, remove the solvent under reduced pressure, and purify the crude product by column chromatography to obtain intermediates I-c-1 and I-c-2.

[0059] (4) Add the intermediate I-c-1 series (1 eq), (methoxymethyl)triphenylphosphonium chloride (1.3 eq) and tetrahydrofuran to the reaction vessel and stir at room temperature for 10 minutes. Slowly add the potassium tert-butoxide solution dropwise at 0 °C. Then slowly raise the temperature and stir at room temperature for 3 hours. After that, add distilled water. After the reaction is completed, extract the organic layer with ethyl acetate in turn, dry the organic phase with sodium sulfate, remove the solvent by rotary evaporator, and purify it by column chromatography to obtain compound intermediates I-d-1 and I-d-2.

[0060] (5) Add the compound intermediate I-d-1 series, boron trifluoride etherate and dichloromethane to the reaction vessel and stir at 25 °C for 3 hours. After the reaction is completed, extract the organic layer with dichloromethane and water, then dry the extracted organic layer with sodium sulfate, remove the solvent by rotary evaporator, and purify it by column chromatography to obtain intermediate compounds I-e-1 and I-e-2.

[0061] (6) Add the I-e-1 series (1 eq), bis(pinacolato)diboron (1.5 eq), potassium acetate (2 eq) to the reactor, displace the air with nitrogen three times, add 1,4-dioxane as the solvent and displace the air with nitrogen three times again, then add Pd 2 (dba) 3 (0.01 eq) and X-phos (0.08 eq), displace the air with nitrogen three times, and heat up to 100 °C under nitrogen protection for reaction for 12 hours. After the reaction is completed, cool the mixture to room temperature. Subsequently, remove the solvent under reduced pressure, and purify the crude product by column chromatography to obtain intermediates I-f-1 and I-f-2.

[0062] (7) Add the intermediate I-f-1 series (1 eq), chloro-1,3,5-triazine compound (1 eq), potassium carbonate (2 eq) to the reactor, displace the air with nitrogen three times, add a mixture of water and tetrahydrofuran as the solvent and displace the air with nitrogen three times again, then add Pd(Ph 3 ) 4 (0.01 eq), displace the air with nitrogen three times, and heat up to 80 °C under nitrogen protection for reaction for 12 hours. After the reaction is completed, cool the mixture to room temperature. Subsequently, remove the solvent under reduced pressure, and purify the crude product by column chromatography to obtain the final products I-1 and I-2.

[0063]

[0064] 2. The synthesis method of the first main body material general formula I-3-1 is as follows:

[0065] (1) Add 1-methoxy-2-naphthaleneboronic acid (1eq), 2-bromo-6-fluoroiodobenzene (1eq), and potassium carbonate (2eq) into a reactor, displace with nitrogen three times, add a mixture of water and tetrahydrofuran as the solvent and displace with nitrogen three times again, then add Pd(Ph 3 ) 4 (0.01eq), displace with nitrogen three times, and heat to 80 °C under nitrogen protection and react for 12 hours; after the reaction is completed, cool the mixture to room temperature, then, remove the solvent under reduced pressure, and purify the crude product by column chromatography to obtain intermediate I-a-3-1.

[0066] (2) Dissolve intermediate I-a-3-1 (1eq) in anhydrous tetrahydrofuran, stir under nitrogen and cool with an acetone / dry ice bath to control the temperature at -78 °C, slowly drop n-BuLi (1.1eq) into the mixture, keep the internal temperature below -70 °C, stir the mixture at -78 °C for 1 hour, then immediately add iodine (1.1eq) to the mixture, react for 24 hours and maintain the internal temperature at -78 °C, after the reaction is over, raise the temperature to room temperature, and slowly add water and sodium bisulfate solution, separate and retain the organic phase, and extract the water layer with ether. Subsequently, combine the organic phases, remove the solvent under reduced pressure, and purify the crude product by column chromatography to obtain intermediate I-b-3-1.

[0067] (3) Add intermediate I-b-3-1 (1eq), trimethylsilylacetylene (6eq), and CuI (1eq) into a reactor, displace with nitrogen three times, add triethylamine as the solvent and displace with nitrogen three times again, then add Pd(Ph 3 ) 4 (0.01eq), displace with nitrogen three times, and stir at 93 °C for 4 hours; after the reaction is completed, cool the mixture to room temperature, then, remove the solvent under reduced pressure, and purify the crude product by column chromatography to obtain intermediate I-c-3-1.

[0068] (4) Dissolve intermediate I-c-3-1 (1eq) in anhydrous acetonitrile, displace with nitrogen three times, add silver fluoride (1.5eq), stir for 30 min, then add N-iodosuccinimide (1.5eq), react at room temperature for 1 hour, after the reaction is over, filter by suction, and purify the filter cake by column chromatography to obtain intermediate I-d-3-1.

[0069] (5) Add intermediate I-d-3-1 (1 eq) and platinum chloride (0.05 eq) into a reactor, replace the gas with nitrogen three times, add anhydrous toluene as the solvent and replace the gas with nitrogen three times. Stir at 93 °C for 3 hours. After the reaction is completed, perform suction filtration, and purify the filter cake by column chromatography to obtain intermediate I-e-3-1.

[0070] (6) Add intermediate I-e-3-1 (1 eq) into a reaction vessel, replace the gas with nitrogen three times, add dichloromethane as the solvent under nitrogen and replace the gas with nitrogen three times. Slowly add boron tribromide (1.4 eq) to the stirred solution under nitrogen protection at room temperature, react for 1.5 hours, slowly add the reaction mixture to water, stir under nitrogen for 30 minutes, perform suction filtration, filter the filtrate again, wash the precipitate with water several times and dry it in vacuo to obtain intermediate I-f-3-1.

[0071] (7) Add intermediate I-f-3-1 (1 eq) and potassium carbonate (5 eq) into a reaction vessel, replace the gas with nitrogen three times, heat and stir at 120 °C for 1 hour under nitrogen using N-methylpyrrolidone as the solvent. After the reaction is completed, cool the reaction mixture to room temperature, add distilled water to it, filter the precipitate, wash it with water and methanol, and dry it in vacuo to obtain intermediate I-g-3-1.

[0072] (8) Add I-g-3-1 (1 eq), bis(pinacolato)diboron (1.5 eq), and potassium acetate (2 eq) into a reactor, replace the gas with nitrogen three times, add 1,4-dioxane as the solvent and replace the gas with nitrogen three times, then add Pd 2 (dba) 3 (0.01 eq) and X-phos (0.08 eq), replace the gas with nitrogen three times, and heat to 100 °C under nitrogen protection to react for 12 hours; after the reaction is completed, cool the mixture to room temperature, then remove the solvent under reduced pressure, and purify the crude product by column chromatography to obtain intermediate I-h-3-1.

[0073] (9) Add intermediate I-h-3-1 (1 eq), chloro-1,3,5-triazine compound (1 eq), and K 2 CO 3 (2 eq) into a reactor, replace the gas with nitrogen three times, add a mixture of H 2 O and THF as the solvent and replace the gas with nitrogen three times, then add Pd(Ph 3 ) 4 (0.01 eq), replace the gas with nitrogen three times, and heat to 80 °C under nitrogen protection to react for 12 hours; after the reaction is completed, cool the mixture to room temperature, then remove the solvent under reduced pressure, and purify the crude product by column chromatography to obtain the final product I-3-1.

[0074]

[0075] 3. The synthesis method of the first main body material of general formula I-3-2 is as follows:

[0076] (1) Dissolve 3-bromo-1-fluoronaphthalen-2-ol (1 eq) in dichloromethane, add N,N-diisopropylethylamine (6 eq) and trifluoromethanesulfonic anhydride (1.3 eq), and stir the mixture under a nitrogen atmosphere at 0 °C for 0.5 h; quench the reaction mixture with saturated sodium bicarbonate and extract with dichloromethane, dry over sodium sulfate, then remove the solvent under reduced pressure, and purify the crude product by column chromatography to obtain intermediate I-a-3-2.

[0077] (2) Add intermediate I-a-3-2 (1 eq), bis(pinacolato)diboron (1.5 eq), and potassium acetate (3 eq) to the reactor, displace with nitrogen three times, add N,N-dimethylformamide as the solvent and displace with nitrogen three times, then add Pd(dppf)Cl 2 (0.1 eq), displace with nitrogen three times, and heat to 80 °C under nitrogen protection and react for 12 h; after the reaction is completed, cool the mixture to room temperature, then remove the solvent under reduced pressure, and purify the crude product by column chromatography to obtain intermediate I-b-3-2.

[0078] (3) The synthesis route from general formula I-b-3-2 to I-3-2 can be synthesized by referring to the method of I-3-1, and will not be elaborated here.

[0079]

[0080] 4. The synthesis method of general formula I-4 can be synthesized by referring to the above methods of I-1 and I-2, and will not be elaborated here. Its synthesis route is as follows:

[0081]

[0082] 5. Synthesis of the second main body material

[0083] (1) Weigh reactant (1 eq), reactant 2 (1 eq), and sodium tert-butoxide (2 eq) and add them to the reaction vessel in sequence, then add toluene as the reaction solvent, and add catalyst Pd 2 (dba) 3 (0.01 eq) and P(t-Bu) 3 (0.02 eq) under nitrogen protection, reflux at 120 °C for 24 h, then cool to 25 °C, add pure water to it, stir for 30 min, then let it stand for liquid separation, and perform column chromatography to obtain intermediate 2-1.

[0084] (2) The synthesis method of General Formula 2 is the same as that of Synthesis Intermediate 2-1, and will not be elaborated here.

[0085]

[0086] The present invention also provides an organic electroluminescent device, which includes the organic electroluminescent material containing a double host as described above.

[0087] In an 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 in sequence; the material of the light-emitting layer includes the organic electroluminescent material containing a double host as described above and also includes a doping material.

[0088] Moreover, in an embodiment of the present invention, the mass ratio of the organic electroluminescent material containing a double host to the doping material in the light-emitting layer is (5-199):1; preferably (5-100):1, and more preferably (5-15):1.

[0089] In an embodiment of the present invention, the preparation method of the light-emitting layer includes, but is not limited to, forming the light-emitting layer by solution coating method and vacuum deposition method; here, the solution coating method means spin coating, dip coating, inkjet printing, screen printing, spraying method, etc., but is not limited thereto.

[0090] In an embodiment of the present invention, the first electrode is an anode.

[0091] As the anode material, generally, in order to enable holes to be smoothly injected into the organic layer, a material with a large work function is preferred. The anode materials that can be used in the present invention include: metals, such as metals or their alloys like vanadium, chromium, copper, zinc, etc.; metal oxides, such as zinc oxide, indium oxide, indium tin oxide (ITO) or indium zinc oxide (IZO); combinations of metals and oxides, such as ZnO / Al or SnO 2 / Sb; conductive polymers, such as poly(3-methylthiophene), polypyrrole or polyaniline; but not limited thereto. In certain embodiments of the present invention, the anode is an ITO anode.

[0092] In an embodiment of the present invention, the material of the hole injection layer is selected from one or more of metal porphyrins, oligothiophenes, arylamine-based organic materials, benzonitrile-based organic materials, quinacridone-based organic materials, polyaniline-based and polythiophene-based conductive polymers.

[0093] The material of the hole injection layer is a hole material that 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.

[0094] In one embodiment of the present 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 a conjugated part and a non-conjugated part. The material of the hole transport layer can receive holes from the anode or the hole injection layer and transport the holes to the light-emitting layer, and has a high hole mobility.

[0095] In one embodiment of the present invention, the electron transport layer is selected from one or more of Al complexes of 8-hydroxyquinoline and organic radical compounds, but is not limited thereto.

[0096] In one embodiment of the present invention, the thickness of the electron transport layer is 1 nm to 50 nm.

[0097] 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.

[0098] The electron transport layer can prevent the decline of electron transport characteristics, prevent the increase of driving voltage caused by too thick electron transport layer, and play a role in promoting 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, and has a high electron mobility.

[0099] In one embodiment of the present invention, the electron injection layer is selected from one or more of fluorenone, anthraquinone dimethane, biphenylquinone, thiopyran dioxide, imidazole, perylene tetracarboxylic acid, fluoreneylidene methane, anthrone or its derivatives, metal complexes, and nitrogen-containing five-membered ring derivatives, but is not limited thereto.

[0100] The electron injection layer can play a role in promoting electron injection, and the electron injection material preferably has the ability to transport electrons, has an injection electron effect from the cathode, has an excellent electron injection effect on the light-emitting layer or the light-emitting material, prevents excitons generated in the light-emitting layer from migrating to the hole injection layer, and in addition, has an excellent thin film forming ability.

[0101] In one embodiment of the present invention, the second electrode is a cathode.

[0102] As a cathode material, in order to facilitate the injection of electrons into the organic layer, a material with a small work function is generally 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 their alloys; multi-layer structure materials, such as LiF / Al or LiO 2 / Al; but not limited thereto. In some embodiments of the present invention, the cathode material is Al.

[0103] In one embodiment of the present invention, the organic electroluminescent device can be a top-emitting type, a bottom-emitting type or a double-sided emitting type.

[0104] The numerical ranges described in the present invention not only include the above-listed point values, but also include any point values between the above numerical ranges not listed. Due to space limitations and for the sake of simplicity, the specific point values included in the described ranges are not exhaustively listed in the present invention.

[0105] Compared with the prior art, the present invention provides an organic electroluminescent compound, an organic electroluminescent material containing a double host and a light-emitting device, having the following excellent effects:

[0106] The present invention provides an organic electroluminescent material having a double host material. The organic electroluminescent material includes a first host material and a second host material. The first host material is a compound having a structure represented by the general formula (1), and the second host material is a compound having a structure represented by the general formula (2). By using a specific combination of compounds as the host material in an organic electroluminescent device, the luminous efficiency and service life of the device can be effectively improved.

[0107] Specifically, the present invention uses a first host compound with a specific structure and a second host compound with a specific structure in combination. The first host material uses a molecule with a triazine skeleton, which has a high glass transition temperature and molecular thermal stability, appropriate HOMO and LUMO energy levels, and a high Eg. At the same time, it is paired with a second host having a triarylamine structure, which can enhance the hole transport and electron transport capabilities simultaneously. Therefore, when holes are injected into the p-type host and electrons are injected into the n-type host, while reducing the driving voltage, the lifetime is also enhanced. Description of the Drawings

[0108] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained according to the provided drawings without creative efforts.

[0109] Figure 11H NMR spectrum of compound H1-63 provided in the embodiments of the present invention. Detailed implementation manners

[0110] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention and the relevant drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0111] The present invention specifically discloses an organic electroluminescent compound, an organic electroluminescent material containing a double host, and a light-emitting device.

[0112] It should be noted that the values given in the following embodiments are as accurate as possible. However, those skilled in the art understand that due to inevitable measurement errors and experimental operation problems, each number should be understood as an approximate number rather than an absolutely accurate value.

[0113] Refer to the common general knowledge as follows:

[0114] "Organotransition Metal Chemistry" (Original Sixth Edition), Robert H. Crabtree, Publisher: East China University of Science and Technology Press, Shanghai, Publication Date: 2017-09-00, ISBN: 978-7-5628-5111-0, Page 388.

[0115] "Experimental Course of Organic Chemistry and Optoelectronic Materials", Chen Runfeng, Publisher: Southeast University Press, Publication Date: 2019-11-00, ISBN: 9787564184230, Page 174.

[0116] The features and properties of the present invention will be further described in detail below in conjunction with the embodiments.

[0117] Example 1: Preparation of the first host compound H1-63

[0118] (1) Add 2-bromo-6-chloro-1-naphthol (156 mmol), bis(pinacolato)diboron (234 mmol), and potassium acetate (312 mmol) to the reactor, displace with nitrogen three times, add 1,4-dioxane as the solvent and displace with nitrogen three times, and then add Pd 2 (dba) 3(1.56 mmol) and X-phos (12.48 mmol) were purged with nitrogen three times, and the temperature was raised to 100 °C under nitrogen protection and reacted 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 H1-63-a (36.11 g, yield 76%, HPLC > 99%, mass spectrometry test value 304.79).

[0119] (2) Intermediate H1-63-a (110 mmol), 2-bromo-3-fluorobenzaldehyde (110 mmol), and potassium carbonate (220 mmol) were added to the reactor and purged with nitrogen three times. A mixture of water and tetrahydrofuran was added as the solvent and purged with nitrogen three times. Then Pd(Ph 3 ) 4 (1.1 mmol) was purged with nitrogen three times, and the temperature was raised to 80 °C under nitrogen protection and reacted 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 H1-63-b (24.15 g, yield 73%, HPLC > 99%, mass spectrometry test: theoretical value 300.71, test value 300.95).

[0120] (3) Intermediate H1-63-b (80 mmol) and potassium carbonate (240 mmol) were added to the reactor and purged with nitrogen three times. DMAc was added as the solvent and purged with nitrogen three times. The mixture was stirred and the temperature was raised to 170 °C and reacted for 9 hours. After the reaction was completed, it 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 H1-63-c (18.86 g, yield 84%, HPLC > 99%, mass spectrometry test value 280.96).

[0121] (4) Intermediate H1-63-c (65 mmol), (methoxymethyl)triphenylphosphonium chloride (84.5 mmol), and THF (325 mL) were added to the reaction vessel and stirred at room temperature for 10 minutes. A solution of potassium tert-butoxide (prepared by dissolving 7.69 g of potassium tert-butoxide in 68.5 mL of tetrahydrofuran) was slowly added dropwise at 0 °C; then, the temperature was slowly raised, and 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 in sequence, the organic phase was dried over sodium sulfate, and the solvent was removed by a rotary evaporator; then it was purified by column chromatography to obtain compound intermediate H1-63-d (15.05 g, yield 75%, HPLC > 99%, mass spectrometry test value 308.98).

[0122] (5) The compound intermediate H1-63-d (48 mmol), boron trifluoride etherate (12.1 mL), and dichloromethane (480 mL) were 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, and then dried over sodium sulfate. After that, the solvent was removed under reduced pressure. Thereafter, it was purified by column chromatography to obtain intermediate compound H1-63-e (9.43 g, yield 71%, HPLC > 99%, mass spectrometry test value 276.96).

[0123] (6) H1-63-e (34 mmol), bis(pinacolato)diboron (51 mmol), and potassium acetate (68 mmol) were added to a reactor and purged with nitrogen three times. 1,4-Dioxane was added as a solvent and purged with nitrogen three times. Then Pd 2 (dba) 3 (0.34 mmol) and X-phos (2.72 mmol) were added and purged with nitrogen three times, and the temperature was raised to 100 °C under nitrogen protection and reacted 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 H1-63-f (10.26 g, yield 82%, HPLC > 99%, mass spectrometry test: theoretical value 368.24, test value 368.53).

[0124] (7) Intermediate H1-63-f (27 mmol), 2-([1,1'-biphenyl]-3-yl)-4-chloro-6-(dibenzo[b,d]furan-2-yl)-1,3,5-triazine (27 mmol), and potassium carbonate (54 mmol) were added to a reactor and purged with nitrogen three times. A mixture of water and tetrahydrofuran was added as a solvent and purged with nitrogen three times. Then Pd(Ph 3 ) 4 (0.027 mmol) was added and purged with nitrogen three times, and the temperature was raised to 80 °C under nitrogen protection and reacted 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 the final product H1-63 (13.30 g, yield 77%, HPLC > 99%, mass spectrometry test value 639.96, nuclear magnetic resonance hydrogen spectrum as shown in Figure 1 Figure).

[0125]

[0126] Example 2: Preparation of the first host compound H1-183

[0127] Add intermediate H1-63-f (20 mmol), 2-[1,1′-biphenyl]-4-yl-4-chloro-6-(phenyl-2,3,4,5,6-d5)-1,3,5-triazine (20 mmol), and potassium carbonate (40 mmol) into a reactor, displace the air with nitrogen three times, add a mixture of H 2 O and THF as the solvent and displace the air with nitrogen three times again, then add Pd(Ph 3 ) 4 (0.02 mmol), displace the air with nitrogen three times, and heat to 80 °C under nitrogen protection and react for 12 hours; after the reaction is completed, cool the mixture to room temperature, then remove the solvent under reduced pressure, and purify the crude product by column chromatography to obtain the final product H1-183 (8.98 g, yield 81%, HPLC > 99%, mass spectrometry test value 554.92).

[0128]

[0129] Example 3: Preparation of the second host compound H2-10

[0130] Weigh N-(phenyl-d5)naphthalen-2-amine (59.81 mmol), 9-chloro-2-phenylphenanthro[3,4-d]oxazole (59.81 mmol), and sodium tert-butoxide (119.62 mmol) into a reaction flask, add 200 mL of toluene, add the catalyst Pd 2 (dba) 3 (0.60 mmol) and P(t-Bu) 3 (1.20 mmol) under nitrogen protection, reflux at 120 °C for 24 hours under nitrogen protection, then cool to 25 °C, add 200 mL of pure water thereto, stir for 30 min, then let it stand for liquid separation, separate the liquid, and perform column chromatography to obtain the product H2-10 (22.60 g, yield 73%, HPLC > 99%, mass spectrometry test value 517.87), and the reaction route is shown as follows.

[0131]

[0132] Example 4: Preparation of the second host compound H2-28

[0133] Weigh N-([1,1'-biphenyl]-4-yl)-[1,1'-biphenyl]-3-amine (59.81 mmol), 10-chloro-2-phenylphenanthro[3,4-d]oxazole (59.81 mmol), and sodium tert-butoxide (119.62 mmol) into a reaction flask, add 200 mL of toluene, add the catalyst Pd 2 (dba) 3 (0.60 mmol) and P(t-Bu) 3(1.20 mmol), reflux at 120 °C for 24 hours under nitrogen protection, then cool to 25 °C, add 200 mL of pure water thereto, stir for 30 minutes, then let it stand for liquid separation, separate the liquid, and perform column chromatography to obtain product H2-10 (28.68 g, yield 78%, HPLC > 99%, mass spectrometry test value 614.96). The reaction route is as follows.

[0134]

[0135] In addition, it should be noted that other compounds of the present invention can be obtained by referring to the synthesis methods of the above-listed examples, so they will not be listed one by one here.

[0136] The test data of other examples are shown in Table 1

[0137] Table 1

[0138]

[0139]

[0140] Device Examples 1 to 24, Comparative Examples 1 to 3, Parallel Comparative Examples 1-10:

[0141] Device Examples 1 to 24, Comparative Examples 1 to 3, and Parallel Comparative Examples 1-10 respectively provide a host material. The combination of the host materials is shown in Table 2. Among them, for the organic electroluminescent material containing a double host including a first host compound and a second host compound, the mass ratio of the first host compound to the second host compound is 1:9 - 9:1, preferably 6:4. In Table 2, "-" indicates that the compound is not in the host material. The structures of D-1 and D-2 are as follows.

[0142]

[0143] Table 2

[0144]

[0145]

[0146] The preparation method of the organic electroluminescent device The preparation method of the organic electroluminescent device is as follows:

[0147] (1) Wash the ITO (indium tin oxide) glass substrate with a thickness of 1500 Å twice in distilled water, ultrasonically wash for 30 minutes, then wash repeatedly twice with distilled water, ultrasonically wash for 10 minutes. After the washing is completed, ultrasonically wash with methanol, acetone, and isopropanol in sequence (each washing for 5 minutes), dry, and then transfer it to a plasma cleaner for washing for 5 minutes to obtain the ITO anode.

[0148] (2) In the evaporation coater, a hole injection layer (HIL) with a thickness of 700 Å is vacuum-evaporated on the surface of the ITO anode obtained in step (1), and the structure of the HIL is as follows:

[0149]

[0150] (3) On the surface of the hole injection layer obtained in step (2), a hole transport layer (HTL) is vacuum-evaporated. First, a 50-Å-thick HTL1 is evaporated, and then a 700-Å-thick HTL2 is evaporated on its surface to jointly form the hole transport layer. The structure of the HTL is as follows:

[0151]

[0152] (4) On the surface of the hole transport layer, a light-emitting layer material is evaporated. Linear gradient co-evaporation is carried out by the method of multi-source co-evaporation with a thickness of 300 Å to obtain the light-emitting layer. The material of the light-emitting layer includes an organic electroluminescent material containing a double host and a doping material. The mass ratio of the first host compound to the second host compound in the organic electroluminescent material containing a double host is 6:4, and the mass ratio of the organic electroluminescent material containing a double host to the doping material is 10:1. The organic electroluminescent materials containing a double host are the host materials provided in Examples 1 to 24 and Comparative Examples 1 to 3, and Parallel Comparative Examples 1 to 10 respectively. The structure of the doping material is as follows:

[0153]

[0154] (5) On the surface of the light-emitting layer obtained in step (4), a hole-blocking layer (HBL) with a thickness of 100 Å is evaporated to form the hole-blocking layer. The structure of the HBL is as follows:

[0155]

[0156] (6) On the surface of the hole-blocking layer obtained in step (5), an electron transport layer (ETL) with a thickness of 300 Å is vacuum-evaporated to obtain the electron transport layer. The structure of the ETL is as follows:

[0157]

[0158] (7) On the surface of the electron transport layer obtained in step (6), an electron injection layer (EIL(Liq)) with a thickness of 15 Å is vacuum-evaporated to obtain the electron injection layer. The structure of the EIL is as follows:

[0159]

[0160] (8) On the surface of the electron injection layer obtained in step (7), 1200 Å of Al is evaporated to form the cathode, and thus the organic electroluminescent device can be obtained.

[0161] The driving voltage, luminous efficiency of the organic electroluminescent device were tested at a brightness of 15,000 nits, and the time (lifetime; T95) taken for the brightness to decrease from 100% to 95% was measured. The test results are shown in Table 3.

[0162] Table 3

[0163]

[0164]

[0165] From the comparison between Comparative Example 3 and Comparative Examples 1-2, it can be seen that when the host materials of the light-emitting layer are compounded with the first host compound and the second host compound, the luminous efficiency and service life can be significantly improved. If only any one of them is selected, the luminous efficiency of the device will be significantly reduced, the service life will be significantly shortened, and the voltage will increase.

[0166] From the comparison between Device Examples 1-24 and Parallel Comparative Examples 1-10, it can be seen that the efficiency of Parallel Comparative Examples 1-10 is 34.1-36.8 cd / A, the driving voltage is 3.41-3.56 V, and the lifetime is 461-488 h. While the luminous efficiency of Examples 1-24 of the present invention is 38.5-44.8 cd / A, which is significantly higher than that of Parallel Comparative Examples 1-10; the driving voltage is 3.14-3.29 V, which is significantly lower than that of Parallel Comparative Examples 1-10; the lifetime is 567-608 h, which is much higher than that of Parallel Comparative Examples 1-10.

[0167] Therefore, it can be seen that when the host materials of the light-emitting layer are compounded with the first host compound with a specific structure and the second host compound with a specific structure of the present invention, the luminous efficiency and service life can be significantly improved. This is because the present invention not only provides a first host material with a triazine skeleton, which has a high glass transition temperature and molecular thermal stability, appropriate HOMO and LUMO energy levels, and a high Eg, but also provides a second host with a triarylamine structure for matching, which can not only enhance the hole transport ability but also provide good electron transport ability. Therefore, when holes are injected into the p-type host and electrons are injected into the n-type host, the driving voltage will decrease and the lifetime will also be enhanced.

[0168] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An organic electroluminescent compound, characterized in that: The organic electroluminescent compound is a first host compound having a structure represented by the general formula (1): Wherein, L1 and L2 are each independently selected from a connecting bond, a substituted or unsubstituted (C6-C 30 ) aryl, substituted or unsubstituted (C6-C 30 ) heteroaryl; Ar1 and Ar2 are each independently selected from substituted or unsubstituted (C6-C 30 ) aryl, substituted or unsubstituted (C6-C 30 ) heteroaryl, substituted or unsubstituted (C 10 -C 30 ) of a fused ring group; wherein the heteroaryl group includes a monocyclic aromatic group or a polycyclic aromatic system containing at least one heteroatom, and the heteroatom includes but is not limited to O, S, and N.

2. The organic electroluminescent compound according to claim 1, characterized in that The general formula (1) has the compound structures shown in I-1 to I-4:

3. The organic electroluminescent compound according to claim 1 or 2, characterized in that: Ar1 and Ar2 are each independently selected from substituted or unsubstituted phenyl, naphthyl, biphenyl, benzodimethylfluorenyl, benzofuranyl, benzothiophenyl, phenanthrene, benzodiphenylfluorenyl, tert-butylphenyl, and cyanophenyl; L1 and L2 are each independently selected from a connecting bond.

4. The organic electroluminescent compound according to claim 3, characterized in that The "substitution" is selected from deuterium, cyano, methyl, C6-C 24 Aryl, C6-C 24 Heteroaryl, wherein the heteroatom is selected from O, S, N.

5. The organic electroluminescent compound according to claim 1 or 2, characterized in that: The structure of the organic electroluminescent compound includes but is not limited to any one of the following compounds:

6. An organic electroluminescent material containing a double host, characterized in that: The organic electroluminescent material containing two hosts comprises a first host material and a second host material, wherein the mass ratio of the first host material to the second host material is 1:9-9:1; the first host material comprises at least one of the organic electroluminescent compounds represented by the general formula (1), and the second host material comprises a structure represented by the general formula (2): Wherein, L1 to L3 are each independently selected from a connecting bond, a substituted or unsubstituted (C6-C 30 ) aryl, substituted or unsubstituted (C6-C 30 ) heteroaryl; Ar1 to Ar3 are each independently selected from substituted or unsubstituted (C6-C 30 ) aryl, substituted or unsubstituted (C6-C 30 ) heteroaryl, substituted or unsubstituted (C 10 -C 30 ) of a fused ring group; wherein the heteroaryl group is a monocyclic aromatic group or a polycyclic aromatic system including at least one heteroatom, and the heteroatom includes but is not limited to O, S, and N.

7. The organic electroluminescent material containing a double host according to claim 6, characterized in that: Ar1 is selected from C6-C 36 Aryl, substituted or unsubstituted C3-C 30 Heteroaryl, which is a monocyclic aromatic group or a polycyclic aromatic system containing at least one heteroatom, including but not limited to O, S, and N; Ar2 and Ar3 are each independently selected from substituted or unsubstituted phenyl, biphenyl, terphenyl; L2 and L3 are each independently selected from a connecting bond; L1 is selected from a linker, an unsubstituted C6-C 18 Aryl, substituted or unsubstituted C6-C 18 Heteroaryl, wherein the heteroatom is selected from O, S, N; The "substitution" is selected from deuterium, cyano, methyl, C6-C 24 Aryl, C6-C 24 Heteroaryl, wherein the heteroatom is selected from O, S, N.

8. The organic electroluminescent material containing a double host according to claim 6, characterized in that: The structure of the second host material includes but is not limited to any one of the following compounds:

9. An organic electroluminescent device, characterized in that: The organic electroluminescent device comprises the organic electroluminescent compound according to claim 1 or the organic electroluminescent material containing a double host according to claim 6 .

10. The organic electroluminescent device according to claim 9, characterized in that: The organic electroluminescent device 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 arranged in sequence; the material of the light-emitting layer comprises the organic electroluminescent material containing a double host.

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