Quinoxaline compound and organic electroluminescent device

Abstract

The invention provides a quinoxaline compound and an organic electroluminescent device, and belongs to the technical field of electroluminescent materials. The quinoxaline compound has a structure as shown in a formula I. The structure of the quinoxaline compound is designed, so that the quinoxaline compound is suitable for being used as a main body material of a light-emitting layer of the organic light-emitting device, and the organic light-emitting device has relatively high current efficiency, relatively long service life and relatively low driving voltage.

Description

Technical Field

[0001] The present invention belongs to the technical field of electroluminescent materials, and particularly relates to a quinoxaline compound and an organic electroluminescent device. Background Art

[0002] Electroluminescence, also known as field luminescence, abbreviated as EL, is a luminescence phenomenon in which an electric field is generated by a voltage applied across two electrodes, and a solid directly converts electrical energy into light energy under the action of the electric field. Among them, the electroluminescence of organic materials belongs to injection-type recombination luminescence. According to the functions in an organic electroluminescent (OLED) device and the different device structures, organic electroluminescent materials can be further classified into materials such as a hole injection layer (HIL), a hole transport layer (HTL), a light-emitting layer (EML), an electron transport layer (ETL), and an electron injection layer (EIL).

[0003] Currently, organic electroluminescence (OLED) has become the mainstream display technology. Correspondingly, various new OLED materials have been developed. However, various performances thereof still need to be improved, especially in terms of efficiency, lifespan, voltage, etc. In order to meet people's higher requirements for OLED devices, there is an urgent need in this field to develop more types of blue host materials with higher performances. Summary of the Invention

[0004] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a quinoxaline compound and an organic electroluminescent device. In the present invention, by designing the structure of the quinoxaline compound, it is made applicable as the host material of the light-emitting layer of an organic electroluminescent device, so that the organic electroluminescent device has a high current efficiency, a long lifespan, and a low driving voltage.

[0005] To achieve this purpose, the present invention adopts the following technical solutions:

[0006] In the first aspect, the present invention provides a quinoxaline compound, and the quinoxaline compound has a structure shown in the following formula I:

[0007]

[0008] Among them, Ar is selected from any one of C6-C40 aryl or C6-C30 heteroaryl;

[0009] R 1 、R 2 、R 3 、R 4 are each independently selected from any one of C6-C40 aryl or C6-C30 heteroaryl;

[0010] m, n, a, b are independently selected from integers between 0 and 4;

[0011] Each hydrogen atom in the compound of formula I may independently be substituted by at least one of a deuterium atom (D), -F, -CN, a C6-C20 aryl group, a C1-C12 alkyl group, or a C1-C12 alkoxy group.

[0012] In the present invention, by designing the structure of quinoxaline compounds, they are suitable as host materials for the light-emitting layer of organic electroluminescent devices, enabling the organic electroluminescent devices to have high current efficiency, long lifespan, and low driving voltage.

[0013] It should be noted that in the present invention, "D" represents a deuterium atom. Where not separately indicated in the present invention, H and hydrogen both represent "protium", and the same applies hereinafter.

[0014] In the present invention, C6-C40 may be C6, C8, C10, C12, C16, C20, C24, C28, C30, C32, C36, or C40, etc.

[0015] C6-C30 may be C6, C8, C10, C12, C16, C20, C24, C28, or C30, etc.

[0016] C1-C12 may be C1, C2, C4, C6, C8, C10, or C12, etc.

[0017] C6-C20 may be C6, C8, C10, C12, C16, or C20, etc.

[0018] The following are preferred technical solutions of the present invention, but do not limit the technical solutions provided by the present invention. Through the following preferred technical solutions, the objectives and beneficial effects of the present invention can be better achieved and realized.

[0019] As a preferred technical solution of the present invention, the C6-C40 aryl group is selected from any one of phenyl, biphenyl, terphenyl, naphthyl, naphthylphenyl, anthryl, phenanthryl, fluorenyl, benzofluorenyl, dibenzofluorenyl, naphthofluorenyl, pyrenyl, perylenyl, spirofluorene, triphenylene, fluoranthenyl, hydrobenzanthryl, indeno[1,2-b]fluorene, benzo[ghi]fluorene, dibenzo[ghi]fluorene, naphthofluorenyl, or benzonaphthofluorenyl.

[0020] As a preferred technical solution of the present invention, the C6-C30 heteroaryl group is selected from any one of carbazolyl, dibenzofuranyl, dibenzothiophenyl, naphthobenzofuranyl, naphthobenzothiophenyl, dinaphthofuranyl, or dinaphthothiophenyl.

[0021] As a preferred technical solution of the present invention, the C6-C20 aryl group is selected from any one of phenyl, biphenyl, terphenyl, naphthyl, anthryl, phenanthryl, fluorenyl, triphenylene, or fluoranthenyl.

[0022] As a preferred technical solution of the present invention, the C1-C12 alkyl group is selected from any one of methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl or decyl.

[0023] As a preferred technical solution of the present invention, the C1-C12 alkoxy group is selected from any one of methoxy, ethoxy, propoxy, butoxy, pentyloxy or hexyloxy.

[0024] As a preferred technical solution of the present invention, Ar is selected from any one of phenyl, carbazolyl, biphenyl, fluorene, naphthyl, triphenylene, fluoranthene, indeno[1,2-b]fluorene, dibenzofuran, dibenzothiophene, naphtho[2,3-b]benzofuran or naphtho[2,3-b]benzothiophene.

[0025] Preferably, Ar is selected from any one of phenyl, naphthyl, biphenyl, fluorene, carbazolyl, dibenzofuran or dibenzothiophene.

[0026] As a preferred technical solution of the present invention, the R 1 , R 2 , R 3 , R 4 each independently is selected from any one of phenyl, carbazolyl, biphenyl, fluorene, naphthyl, triphenylene, fluoranthene, indeno[1,2-b]fluorene, dibenzofuran, dibenzothiophene, naphtho[2,3-b]benzofuran or naphtho[2,3-b]benzothiophene.

[0027] Preferably, the R 1 , R 2 , R 3 , R 4 each independently is selected from any one of phenyl, biphenyl, naphthyl or carbazolyl.

[0028] As a preferred technical solution of the present invention, m + n = 1. As a preferred technical solution of the present invention, m + n = 2.

[0029] As a preferred technical solution of the present invention, m = 2 and n = 0.

[0030] As a preferred technical solution of the present invention, m = 1 and n = 1.

[0031] As a preferred technical solution of the present invention, a + b = 1.

[0032] As a preferred technical solution of the present invention, a + b = 2.

[0033] As a preferred technical solution of the present invention, a = 2 and b = 0.

[0034] As a preferred technical solution of the present invention, a = 1 and b = 1.

[0035] As a preferred technical solution of the present invention, the hydrogen atoms in the compound of formula I can each independently be substituted by at least one of -D, -F, -CN, phenyl, naphthyl, biphenyl, methyl, ethyl, propyl, butyl, methoxy, ethoxy, propoxy or butoxy.

[0036] Preferably, the hydrogen atoms in the compound of formula I can each independently be substituted by at least one of -D, -F, -CN, methyl, ethyl, propyl, tert-butyl, methoxy, phenyl or naphthyl.

[0037] As a preferred technical solution of the present invention, the quinoxaline compounds are selected from any one of the following substituted or unsubstituted compounds:

[0038]

[0039]

[0040] The substitution means that the hydrogen atoms in the above quinoxaline compounds can each independently be substituted by deuterium atoms.

[0041] Preferably, the quinoxaline compounds are selected from any one of the following compounds:

[0042]

[0043] It should be noted that the present invention has no special restrictions on the preparation methods of the above quinoxaline compounds, and the commonly used preparation methods in the art are applicable.

[0044] In a second aspect, the present invention provides an intermediate, and the intermediate includes the following compounds:

[0045]

[0046] Wherein, Ar has the same definition as above;

[0047] X 2 、X 3 Each independently is selected from any one of -F, -Cl, -Br, -I;

[0048] The intermediate is used for preparing the quinoxaline compounds as described in the first aspect.

[0049] As a preferred technical solution of the present invention, the intermediate is selected from the following compounds:

[0050]

[0051] It should be noted that the present invention has no special restrictions on the preparation method of the above-mentioned intermediate, and the commonly used preparation methods in the art are applicable. For example, the synthesis method of the intermediate of the present invention includes the following steps:

[0052]

[0053] Among them, Ar has the same definition as above;

[0054] X 1 、X 2 、X 3 Each independently selected from any one of -F, -Cl, -Br, -I. Those skilled in the art can select the specific types of X 1 、X 2 、X 3 according to common general knowledge.

[0055] In a third aspect, the present invention provides an organic electroluminescent device, which includes an anode, a cathode, and an organic thin film layer disposed between the anode and the cathode;

[0056] The organic thin film layer includes the quinoxaline compound as described in the first aspect.

[0057] As a preferred technical solution of the present invention, the organic thin film layer includes a light-emitting layer, and the host material of the light-emitting layer includes the quinoxaline compound as described in the first aspect.

[0058] Preferably, the light-emitting layer is a phosphorescent light-emitting layer.

[0059] As a preferred technical solution of the present invention, the organic electroluminescent device is a blue organic electroluminescent device.

[0060] In the present invention, the light-emitting layer includes a light-emitting layer host material and a doping material, where the doping material is also called a dye or a phosphorescent light-emitting material. The light-emitting layer host material can be a single compound or a mixture formed by two or more compounds.

[0061] The light-emitting layer includes a phosphorescent light-emitting layer, and the phosphorescent light-emitting layer includes a green phosphorescent light-emitting layer, a red phosphorescent light-emitting layer, and a yellow phosphorescent light-emitting layer.

[0062] The volume percentage content of the host material in the phosphorescent light-emitting layer is 60% - 99.9% (for example, it can be 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98% or 99.9%, etc.), preferably 70% - 99.5%, and further preferably 85% - 95%.

[0063] In the present invention, the doping material of the light-emitting layer can be a phosphorescent material, also known as a triplet light-emitting material, which refers to the light emitted by a substance from a triplet excited state. In the present invention, the specific selection of the phosphorescent material is not particularly limited, and any doping material of the light-emitting layer commonly used in the art is applicable. Exemplarily, but not limited to, compounds having a structure represented by formula PD:

[0064]

[0065] wherein M is selected from any one of Ir, Pt, Pd, Os, Ti, Zr, Hf, Eu, Tb, Tm, Cu or Au;

[0066] Y 1 -Y 4 each independently is selected from carbon or nitrogen;

[0067] Y 1 and Y 2 can be connected by a single bond or a double bond, and Y 3 and Y 4 can be connected by a single bond or a double bond;

[0068] Cy 1 and Cy 2 each independently is selected from any one of phenyl, naphthyl, fluorenyl, spirofluorenyl, indenyl, pyrrolyl, thienyl, furyl, imidazolyl, pyrazolyl, thiazolyl, isothiazolyl, pyridyl, pyrazinyl, pyrimidinyl, pyridazinyl, quinolinyl, isoquinolinyl, benzoquinolinyl, quinoxalinyl, quinazolinyl, carbazolyl, benzimidazolyl, benzofuryl, benzothienyl, isobenzothienyl, benzimidazazolyl, benzazolyl, triazolyl, tetrazolyl, dioxazolyl, triazinyl, dibenzofuryl, dibenzothienyl, N-heterocarbazolyl, N-heterodibenzofuryl, and Cy 1 and Cy 2 can optionally be connected to each other via a single bond or an organic linking group;

[0069] Between any two ligands of M, between two or more ligands, they can be connected by a single bond, a double bond, or can be bridged by O, S, or can be connected by any chemical group or chemical structure to form a structure form conforming to chemical principles;

[0070] R 91 and R 92 each independently is selected from -H, -D, -F, -Cl, -Br, -I, hydroxyl group, cyano group, nitro group, amino group, amidino group, hydrazino group, hydrazone group, carboxylic acid group, carboxylate group, sulfonic acid group, sulfonate group, phosphoric acid group, phosphate group, -SF 5, any one of substituted or unsubstituted C1-C60 (such as C1, C5, C10, C15, C20, C25, C30, C35, C40, C45, C50, C55 or C60, etc.) alkyl, substituted or unsubstituted C2-C60 (such as C2, C5, C10, C15, C20, C25, C30, C35, C40, C45, C50, C55 or C60, etc.) alkenyl, substituted or unsubstituted C2-C60 (such as C2, C5, C10, C15, C20, C25, C30, C35, C40, C45, C50, C55 or C60, etc.) alkynyl, substituted or unsubstituted C1-C60 (such as C1, C5, C10, C15, C20, C25, C30, C35, C40, C45, C50, C55 or C60, etc.) alkoxy, substituted or unsubstituted C2-C10 (such as C2, C3, C4, C5, C6, C7, C8, C9 or C10) heterocycloalkyl, substituted or unsubstituted C6-C60 (such as C6, C12, C15, C18, C24, C30, C32, C36, C40, C42, C54 or C60, etc.) aryl, substituted or unsubstituted C6-C60 (such as C6, C12, C15, C18, C24, C30, C32, C36, C40, C42, C54 or C60, etc.) aryloxy, substituted or unsubstituted C6-C60 (such as C6, C12, C15, C18, C24, C30, C32, C36, C40, C42, C54 or C60, etc.) arylthio, substituted or unsubstituted monovalent non-aromatic fused polycyclic group, substituted or unsubstituted monovalent non-aromatic fused heteropolycyclic group.

[0071] a 1 and a 2 Each independently is an integer selected from 1-5, such as 1, 2, 3, 4 or 5;

[0072] b is selected from integers from 0-4, such as 0, 1, 2, 3 or 4;

[0073] a is selected from 1, 2 or 3;

[0074] L 1 is a monovalent organic ligand, a divalent organic ligand or a trivalent organic ligand.

[0075] Preferably, the PD compound of the formula is any one of the following compounds:

[0076]

[0077]

[0078]

[0079] In the present invention, the organic thin film layer includes a hole layer, and the hole layer includes a hole injection layer, a hole transport layer, and an electron blocking layer.

[0080] The material of the hole injection layer includes a P-type dopant. The P-type dopant refers to a substance that coexists with the material of the hole injection layer in the OLED device and can oxidize the material of the hole injection layer, thereby acting as an electron acceptor and promoting the movement of holes in the hole injection layer towards the anode. In the present invention, the difference between the absolute value of the LUMO of the P-type dopant and the absolute value of the HOMO of the hole layer material is greater than -0.2V, preferably greater than -0.1eV, more preferably greater than 0eV, still more preferably greater than 0.1eV, and even more preferably greater than 0.2eV.

[0081] The P-type dopant exists in the hole injection layer in a volume ratio of 1% to 10% by volume (for example, it can be 1%, 2%, 4%, 6%, 8%, or 10%, etc.). In the present invention, no special limitation is imposed on the type of the P-type dopant. Exemplarily, the compounds shown as D-1 to D-13 disclosed in CN113728453A can be selected, or the compounds shown as HI-1 to HI-9 described below can be used:

[0082]

[0083] In the present invention, the hole layer material (including the hole injection layer, the hole transport layer, and the electron blocking layer) has the structure shown by the following formula HT-GH4:

[0084]

[0085] wherein, L 41 is selected from a single bond, an aryl group having 6 to 40 carbon atoms (for example, it can be C6, C8, C10, C12, C16, C20, C24, C28, C30, C32, C36, or C40, etc.), or a heteroaryl group having 6 to 20 carbon atoms (for example, it can be C6, C8, C10, C12, C16, or C20, etc.);

[0086] Ar 41 and Ar 42 are each independently selected from an aryl group having 6 to 40 carbon atoms (for example, it can be C6, C8, C10, C12, C16, C20, C24, C28, C30, C32, C36, or C40, etc.), or a heteroaryl group having 6 to 20 carbon atoms (for example, it can be C6, C8, C10, C12, C16, or C20, etc.);

[0087] X is selected from CR 41 R 42 or NR 43 , where R 41 and R42 and R 43 are each independently selected from a substituted or unsubstituted phenyl group (the substituents of the substituted phenyl group are selected from C1-C6 (e.g., C1, C2, C3, C4, C5, or C6) alkyl groups, C1-C6 (e.g., C1, C2, C3, C4, C5, or C6) alkoxy groups, dibenzofuranyl groups), naphthyl groups, triphenylenyl groups, fluoranthenyl groups, 9,9-dimethylfluorenyl groups, biphenyl groups, substituted or unsubstituted dibenzofuranyl groups (the substituents of the substituted dibenzofuranyl group are phenyl groups), substituted or unsubstituted dibenzothiophenyl groups (the substituents of the substituted dibenzothiophenyl group are phenyl groups), dibenzofuran-substituted thiophenyl groups, and any one of C1-C6 (e.g., C1, C2, C3, C4, C5, or C6) alkyl groups. R 41 and R 42 can be connected by a single bond to form a ring.

[0088] The compound of formula HT-GH4 is selected from any one of the following compounds:

[0089]

[0090]

[0091]

[0092] In the present invention, the hole layer material (including the hole injection layer, hole transport layer, and electron blocking layer) further includes a compound having a structure shown in formula IA or a compound having a structure shown in formula IB:

[0093]

[0094] wherein, L is selected from any one of arylene groups containing C6-C40 (e.g., C6, C8, C10, C12, C16, C20, C24, C28, C30, C32, C36, or C40, etc.), di(dibenzofuranyl) groups, or di(dibenzothiophenyl) groups;

[0095] m is an integer between 0 and 4 (e.g., 0, 1, 2, 3, or 4), and n is selected from 0 or 1;

[0096] Ar is selected from any one of triphenyleneylene groups, fluoranthenylene groups, dibenzofuranylene groups, or dibenzothiophenylene groups;

[0097] Ar 1 and Ar 2 are each independently selected from any one of aryl groups containing C6-C40 (e.g., C6, C8, C10, C12, C16, C20, C24, C28, C30, C32, C36, or C40, etc.), dibenzofuranyl groups, or dibenzothiophenyl groups;

[0098] Ar 1 Between Ar and Ar, Ar 2 Between Ar and Ar, and Ar 1 Ar 2 Independently of each other, they can be connected or bridged by a single bond, O, S, CR 1 R 2 or NR.

[0099] R, R 1 R 2 Independently of each other, each is selected from C1-C20 (such as C1, C2, C4, C6, C8, C10, C12, C14, C16, C18 or C20, etc.) alkyl, C6-C40 (such as C6, C8, C10, C12, C16, C20, C24, C28, C30, C32, C36 or C40, etc.) aryl, dibenzofuranyl or dibenzothiophenyl;

[0100] The H in the compound of formula IB and the compound of formula IA can independently of each other be replaced by at least one of -F, -CN, -D (deuterium atom), C1-C6 alkyl, C1-C6 alkoxy, phenyl, biphenyl, naphthyl, phenanthryl, anthracenyl, fluorenyl, benzofluorenyl, dibenzofluorenyl, triphenylene, fluoranthenyl, pyrenyl, perylenyl, spirofluorene, indeno[1,2-b]fluorene or hydrogenated benzanthracenyl.

[0101] Preferably, the Ar is fluoranthenylidene, and m + n > 1.

[0102] Preferably, the H in the compound of formula IB and the compound of formula IA can be replaced by at least one of -F, -CN, -D, C1-C3 alkyl (such as methyl, ethyl or propyl), C1-C3 alkoxy (such as methoxy, ethoxy or propoxy), phenyl, biphenyl, triphenylene, fluoranthenyl.

[0103] Preferably, the L, Ar 1 Ar 2 Independently of each other, each is selected from at least one of phenyl, biphenyl, naphthyl, phenanthryl, anthracenyl, fluorenyl, benzofluorenyl, dibenzofluorenyl, triphenylene, fluoranthenyl, pyrenyl, perylenyl, spirofluorene, indeno[1,2-b]fluorene or hydrogenated benzanthracenyl.

[0104] Preferably, the compound of formula IB is selected from the following structures:

[0105]

[0106] wherein L is phenylene;

[0107] Ar 1 Ar 2, m has the same definition as described above.

[0108] Preferably, the compound of Formula IB is selected from any one of the following compounds:

[0109]

[0110]

[0111] In the OLED device provided by the present invention, in addition to the compounds of Formula HT-GH4, Formula IB, and Formula IA, the hole layer material may simultaneously include conventional hole materials in the art without particular limitation. Exemplarily, but not limited to: triarylamine compounds or carbazole compounds. Preferably, triarylamine compounds or carbazole compounds containing more than 3 N atoms are used because the HOMO of triarylamine compounds or carbazole compounds containing more than 3 N atoms is higher (with a smaller absolute value), and they are more suitable as hole injection layer materials. Triarylamine compounds or carbazole compounds containing 2 or 1 N atoms can be used as hole transport layer materials. Some compounds containing 1 N atom or carbazole compounds, if they have a relatively high LUMO, can also be used as electron blocking layer materials.

[0112] As the hole layer material, the triarylamine compound or carbazole compound has the following structure:

[0113]

[0114] Wherein, Ar 601 ~Ar 609 are each independently selected from substituted or unsubstituted C6-C40 (such as C6, C8, C10, C12, C16, C20, C24, C28, C30, C32, C36 or C40, etc.) aryl groups, substituted or unsubstituted dibenzofuranyl groups, substituted or unsubstituted dibenzothiophenyl groups, substituted or unsubstituted naphthobenzofuranyl groups, substituted or unsubstituted naphthobenzothiophenyl groups, substituted or unsubstituted dinaphthofuranyl groups, substituted or unsubstituted dinaphthothiophenyl groups;

[0115] And Ar 601 ~Ar 609 Among them, Ar 601 ~Ar 609 adjacent to or connected to the same N atom can be connected by a single bond or bridged by O, S, CR 701 R 702 、NR 703 ;

[0116] R 701 、R 702, R 703 selected from C6-C40 (such as C6, C8, C10, C12, C16, C20, C24, C28, C30, C32, C36 or C40, etc.) aryl groups, C6-C20 (such as C6, C8, C10, C12, C16 or C20, etc.) heteroaryl groups, C1-C6 (such as C1, C2, C3, C4, C5 or C6) alkyl groups, and R 701 , R 702 can be connected by a single bond.

[0117] The hole blocking layer (HBL) can confine holes and / or excitons within the light-emitting layer range to improve the current efficiency and lifetime of the device. Compared with the light-emitting layer material closest to the HBL interface, the HBL material has a lower HOMO (larger absolute value) and / or a higher triplet energy.

[0118] The electron transport layer (ETL) can include materials capable of transporting electrons. The electron transport layer can be intrinsic (undoped) or doped, and doping can be used to enhance conductivity. In the present invention, there is no special limitation on the ETL material, and any metal complex or organic compound can be used as long as it can transport electrons. Generally, the electron transport layer material contains at least one of the following structural fragments: pyridine structure, pyrimidine structure, triazine structure, benzimidazole structure, benzoxazole structure, benzothiazole structure, naphthyridine structure, phenanthridine structure, carbazole structure, dibenzofuran structure, dibenzothiophene structure.

[0119] In the present invention, there is no special limitation on the electron transport layer material, and exemplary ones include but are not limited to:

[0120]

[0121]

[0122]

[0123]

[0124]

[0125] In the present invention, the material of the cathode is a metal with a low work function (such as alkaline earth metals, alkali metals, main group metals or lanthanide elements (such as Ca, Ba, Mg, Al, In, Mg, Yb, Sm, etc.)), a metal alloy composed of multiple metals (an alloy composed of an alkali metal or an alkaline earth metal and silver, such as an alloy composed of magnesium and silver), or a multi-layer structure. If the cathode material is a multi-layer structure, in addition to the metals mentioned above, other metals with a relatively high work function, such as Ag or Al, can also be used. In this case, a combination of the metals is usually used, such as Ca / Ag, Mg / Ag or Ba / Ag.

[0126] It is also possible to select a thin intermediate layer of a material with a high dielectric constant to be introduced between the metal cathode and the organic semiconductor to form a multi-layer structure; the material with a high dielectric constant can also be called an electron injection material, and fluorides of alkali metals or alkaline earth metals, as well as corresponding oxides or carbonates (such as LiF, Li 2 O, BaF 2 , MgO, NaF, CsF, Cs 2 CO 3 etc.) or lithium quinolate (LiQ) can be selected.

[0127] Compared with the prior art, the present invention has the following beneficial effects:

[0128] In the present invention, by designing the structure of quinoxaline compounds, they are suitable as the host material of the light-emitting layer of organic electroluminescent devices, enabling the organic electroluminescent devices to have a high current efficiency, a long service life and a low driving voltage. Specific Embodiments

[0129] To facilitate the understanding of the present invention, the following examples are listed. Those skilled in the art should understand that the examples are only for helping to understand the present invention and should not be regarded as specific limitations on the present invention.

[0130] Preparation Example 1 Synthesis of Intermediate P1-1

[0131] This preparation example provides an intermediate P1-1 and its synthesis method, and the synthesis method is as follows:

[0132]

[0133] Under nitrogen, 50 mL of toluene, 30 mL of ethanol and 20 mL of water were added to a three-necked flask, and then 0.01 mol of compound M1, 0.01 mol of compound M2, 2.12 g (0.02 mol) of sodium carbonate and 0.23 g (0.0002 mol) of tetrakistriphenylphosphine palladium were added thereto. The temperature was slowly raised to 40°C for reaction for 2 hours, then raised to 60°C for reaction for 2 hours, then raised to 80°C for reaction for 4 hours, cooled to room temperature, and separated by adding water. The organic layer was washed with water, dried over magnesium sulfate, and after removing the desiccant, concentrated to dryness, and separated by silica gel column chromatography, eluted with petroleum ether: dichloromethane = 10:1 (volume ratio), to obtain 3.0 g of intermediate P1-1.

[0134] The obtained intermediate P1-1 was subjected to mass spectrometry detection, and the mass-to-charge ratio (m / z) was measured to be 350.04.

[0135] Preparation Example 2-4

[0136] Preparation Examples 2-4 respectively provide an intermediate and a synthesis method thereof. The synthesis method of the corresponding intermediate refers to the synthesis method of intermediate P1-1. Raw material 1 and raw material 2 are reacted to prepare the corresponding intermediate, and the mass spectrum of the prepared intermediate is measured to record m / z. Details are shown in Table 1 below.

[0137] Table 1

[0138]

[0139] Synthesis Example 1 Synthesis of Compound P1

[0140] This synthesis example provides compound P1 and its synthesis method, and the synthesis method is as follows:

[0141]

[0142] Under nitrogen, 100 mL of dry xylene, 3.5 g of intermediate P1-1, 3.5 g of carbazole, and Pd(dba) were added to a three-necked flask. 2 (bis(dibenzylideneacetonepalladium, 0.0575 g, 0.0001 mol), 10% tri-tert-butylphosphine toluene solution (the mass of tri-tert-butylphosphine solution is 0.4 g, the amount of tri-tert-butylphosphine is 0.0002 mol) and sodium tert-butoxide (1.44 g, 0.015 mol), heated to reflux, reacted for 24 hours, cooled to room temperature, added water to separate, then washed with water until neutral, dried with magnesium sulfate, filtered to remove magnesium sulfate, concentrated to dryness, separated by silica gel column chromatography, eluted with a solvent of petroleum ether: dichloromethane = 10: 1 (volume ratio), to obtain compound P1 (2.7 g).

[0143] Mass spectrometry detection was performed on compound P1: the measured mass-to-charge ratio (m / z) was 612.23.

[0144] Synthesis Example 2-4

[0145] Synthesis Example 2-4 respectively provides a compound and its synthesis method. The synthesis method of the corresponding compound refers to the preparation method of compound P1. React raw material 1 and raw material 2 to prepare the corresponding compound, and measure the mass spectrometry of the prepared compound, record m / z, as shown in Table 2 below in detail.

[0146] Table 2

[0147]

[0148] For compounds without specific synthesis methods listed, the above examples can be referred to and combined with common general knowledge in the art for synthesis.

[0149] The specific structures of some compositions used in the following Application Examples and Comparative Application Examples are as follows:

[0150]

[0151]

[0152] Application Example 1

[0153] This application example provides a green organic electroluminescent device, using the compound provided by the present invention as the host material of the light-emitting layer. The structure of the green organic electroluminescent device is as follows:

[0154] ITO / HT-1: HI-2[5%](80nm) / HT-1(30nm) / Host material: PGD-1[5%](35nm) / ETL-1(25nm) / LiF(0.5nm) / Al(150nm).

[0155] The preparation method of the green organic electroluminescent device is as follows:

[0156] Place the materials in a vacuum chamber, evacuate to 1×10 -5 ~1×10 -6 Pa, and vacuum deposit them onto the cleaned ITO substrate in sequence to prepare the OLED device.

[0157] Where PGD-1[5%] refers to the doping ratio of the dye, that is, the volume ratio of the host material to the dye PGD-1 is 95:5; HT-1: HI-2[5%] refers to the ratio of the P-type dopant, that is, the volume ratio of the hole transport material HT-1 and the P-type dopant HI-2 is 95:5. HT-1 is a hole transport material; HT-1: HI-2[5%] is used as the hole injection layer.

[0158] The host material of the light-emitting layer of the green organic electroluminescent device provided in this application example is compound P1.

[0159] Application Example 2 - 8

[0160] Application Examples 2 - 8 respectively provide a green organic electroluminescent device. The difference from Application Example 1 is only that the host material compound P1 of the light-emitting layer is replaced with other compounds (see Table 3 for details), and other preparation steps and conditions are the same as those in Application Example 1.

[0161] Comparative Application Examples 1 - 2

[0162] Comparative Application Examples 1 - 2 respectively provide an organic electroluminescent device. The difference from Application Example 1 is only that the host material compound P1 of the light-emitting layer is replaced with other compounds (see Table 3 for details), and other preparation steps and conditions are the same as those in Application Example 1.

[0163] Performance Test

[0164] Test the brightness, driving voltage, current efficiency, and LT95 of the organic electroluminescent devices provided above. Among them, the voltage and current efficiency are the corresponding values when the brightness is 1000 cd / m 2 The corresponding value, and LT95 refers to the time required for the device efficiency to drop to 95% of the efficiency corresponding to the initial current density while keeping the initial current density of the device at 10 mA / cm 2 unchanged. Among them, the driving voltage, current efficiency, and LT95 are relative values. The specific test results are shown in Table 3:

[0165] Table 3

[0166]

[0167] As can be seen from the above content, in the present invention, by designing the structure of quinoxaline compounds, they are suitable as the host material of the light-emitting layer of organic electroluminescent devices, enabling the organic electroluminescent devices to have higher current efficiency, longer service life, and lower driving voltage.

[0168] Application Examples 9 - 11

[0169] Application Examples 9 - 11 respectively provide a red organic electroluminescent device. The difference from Application Example 1 is only that the host material compound P1 of the light-emitting layer is replaced with other compounds (see Table 4 for details), and PGD - 1 in Application Example 1 is replaced with PRD - 1, and other preparation steps and conditions are the same as those in Application Example 1.

[0170] Comparative Application Example 3

[0171] This comparative application example provides an organic electroluminescent device. The difference from Application Example 1 is only that the host material compound P1 of the light-emitting layer is replaced with other compounds, and PGD-1 in Application Example 1 is replaced with PRD-1 (see Table 4 for details). Other preparation steps and conditions are the same as those in Application Example 1.

[0172] Performance Test

[0173] Test the brightness, driving voltage, current efficiency, and LT95 of the organic electroluminescent device provided above. Among them, the voltage and current efficiency are the corresponding values when the brightness is 1000 cd / m 2 The LT95 refers to the time required for the device efficiency to drop to 95% of the efficiency corresponding to the initial current density while keeping the initial current density of the device at 10 mA / cm 2 unchanged. Among them, the driving voltage, current efficiency, and LT95 are relative values. The specific test results are shown in Table 4:

[0174] Table 4

[0175]

[0176] In the present invention, by designing the structure of the quinoxaline compound, it is suitable as the host material of the light-emitting layer of the organic electroluminescent device, so that the organic electroluminescent device has a high current efficiency, a long lifespan, and a low driving voltage.

[0177] The applicant declares that the present invention uses the above-mentioned embodiments to illustrate the detailed process flow of the present invention, but the present invention is not limited to the above-mentioned detailed process flow, that is, it does not mean that the present invention must rely on the above-mentioned detailed process flow to be implemented. Those skilled in the art should understand that any improvement to the present invention, the equivalent replacement of each raw material of the product of the present invention, the addition of auxiliary components, and the selection of specific methods, etc., all fall within the protection scope and the disclosure scope of the present invention.

Claims

1. A quinoxaline compound, characterized in that: The quinoxaline compound has a structure as shown in the following formula I: Wherein, Ar is selected from any one of C6-C40 aryl or C6-C30 heteroaryl; R1, R2, R3, and R4 are each independently selected from any one of a C6-C40 aryl group or a C6-C30 heteroaryl group; m, n, a, and b are independently selected from integers between 0 and 4; The hydrogen atoms in the compound of formula I may be independently substituted by at least one of a deuterium atom, -F, -CN, a C6-C20 aryl group, a C1-C12 alkyl group or a C1-C12 alkoxy group.

2. The quinoxaline compound according to claim 1, characterized in that The C6-C40 aryl group is selected from any one of phenyl, biphenyl, terphenyl, naphthyl, naphthylphenyl, anthracenyl, phenanthryl, fluorenyl, benzofluorenyl, dibenzofluorenyl, naphthofluorenyl, pyrenyl, peryl, spirofluorenyl, triphenylene, fluoranthenyl, hydrogenated benzanthryl, indenofluorenyl, benzoindenofluorenyl, dibenzoindenofluorenyl, naphthofluorenyl or benzonaphthofluorenyl; The C6-C30 heteroaryl group is selected from any one of carbazolyl, dibenzofuranyl, dibenzothiophenyl, naphthobenzofuranyl, naphthobenzothiophenyl, dinaphthofuranyl, and dinaphthothiophenyl; The C6-C20 aryl group is selected from any one of phenyl, biphenyl, terphenyl, naphthyl, anthracenyl, phenanthryl, fluorenyl, triphenylene, and fluoranthenyl; The C1-C12 alkyl group is selected from any one of methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl or decyl; The C1-C12 alkoxy group is selected from any one of methoxy, ethoxy, propoxy, butoxy, pentyloxy and hexyloxy.

3. The quinoxaline compound according to claim 1, characterized in that The Ar is selected from any one of phenyl, carbazolyl, biphenyl, fluorenyl, naphthyl, triphenylene, fluoranthenyl, indenofluorenyl, dibenzofuranyl, dibenzothienyl, naphthobenzofuranyl or naphthobenzothienyl.

4. The quinoxaline compound according to claim 1, characterized in that The R1, R2, R3, and R4 are each independently selected from any one of phenyl, carbazolyl, biphenyl, fluorenyl, naphthyl, triphenylene, fluoranthenyl, indenofluorenyl, dibenzofuranyl, dibenzothienyl, naphthobenzofuranyl, or naphthobenzothienyl.

5. The quinoxaline compound according to claim 1, characterized in that The m+n=1; or, the m+n=2; Alternatively, m=2, n=0; Alternatively, m=1, n=1; Alternatively, a+b=1; Alternatively, a+b=2; Alternatively, a=2, b=0; Alternatively, a=1, b=1.

6. The quinoxaline compound according to claim 1, characterized in that The hydrogen atoms in the compound of formula I may be independently substituted by at least one of -D, -F, -CN, phenyl, naphthyl, biphenyl, methyl, ethyl, propyl, butyl, methoxy, ethoxy, propoxy or butoxy.

7. The quinoxaline compound according to claim 1, characterized in that The quinoxaline compound is selected from any one of the following substituted or unsubstituted compounds: The substitution means that the hydrogen atoms in the above-mentioned quinoxaline compounds can be independently replaced by deuterium atoms.

8. An intermediate, characterized in that The intermediates include the following compounds: Wherein, Ar has the same definition as in claim 1; X2 and X3 are each independently selected from any one of -F, -Cl, -Br, and -I; The intermediate is used to prepare the quinoxaline compound according to any one of claims 1 to 7.

9. An organic electroluminescent device, characterized in that: The organic electroluminescent device comprises an anode, a cathode and an organic thin film layer arranged between the anode and the cathode; The organic thin film layer comprises the quinoxaline compound according to any one of claims 1 to 7.

10. The organic electroluminescent device according to claim 9, characterized in that: The organic thin film layer comprises a light-emitting layer, and a main material of the light-emitting layer comprises the quinoxaline compound according to any one of claims 1 to 7.

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