Carbazole compound, intermediate and organic electroluminescent device

Abstract

The invention provides a carbazole compound, an intermediate and an organic electroluminescent device, and belongs to the technical field of organic electroluminescent materials. The carbazole compound has a structure as shown in a formula I. Through structural design of the carbazole compound, the carbazole compound with excellent performance is prepared, and the organic light-emitting device prepared by taking the carbazole compound as a material of a light-emitting layer 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 organic electroluminescent materials, and particularly relates to a carbazole compound, an intermediate, and an organic electroluminescent device. Background Art

[0002] Compared with other flat panel displays (such as liquid crystal displays (LCDs), plasma display panels (PDPs), field emission displays (FEDs), etc.), organic electroluminescent devices (OLEDs) have a simpler structure, various processing advantages, higher brightness, excellent viewing angle characteristics, faster response speed, and lower driving voltage. Therefore, they are also fully developed for use as light sources for flat panel displays (such as wall-mounted TVs, etc.), or as backlight units for displays, illuminators, advertising boards, etc.

[0003] The structure of an organic electroluminescent device is specifically: an anode, a cathode, and an organic layer therebetween. To improve the efficiency and stability of the organic electroluminescent element, the organic material layer includes multiple layers with different materials. To meet people's higher requirements for OLED devices, there is an urgent need in this field to develop more types of materials to improve the performance of OLED devices in terms of current efficiency, lifespan, etc. Summary of the Invention

[0004] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a dicarbazole compound, an intermediate, and an organic electroluminescent device. By designing the structure of the carbazole compound, the present invention prepares a carbazole compound with excellent performance. Thus, the organic electroluminescent device prepared with the carbazole compound as the material of the light-emitting layer 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 carbazole compound, and the carbazole compound has the structure shown in Formula I as follows:

[0007]

[0008] Wherein, Ar1 and Ar2 each independently selected from C6-C40 aryl;

[0009] L is selected from any one of a single bond, C6-C40 arylene, dibenzofuranyl, carbazolyl, dibenzothiophenyl, 9,9-dimethylfluorenyl;

[0010] B, B, and C each independently selected from an N atom or CH, and at least one of A, B, and C is selected from an N atom;

[0011] Ar3 and Ar4 are each independently selected from any one of C6-C40 aryl and C6-C30 heteroaryl, and when Ar3 and Ar4 are selected from C6-C30 heteroaryl, the linking site of the C6-C30 heteroaryl is an sp 2 hybridized C atom;

[0012] The hydrogen atoms in Ar3 and Ar4 can each independently be substituted by at least one of -F, -CN, C6-C20 aryl, C6-C30 heteroaryl, triphenylmethyl, triphenylsilyl, C1-C12 alkyl or C1-C12 alkoxy;

[0013] The hydrogen atoms in the compound of formula I can each independently be substituted by deuterium.

[0014] In the present invention, by designing the structure of the carbazole compound, the carbazole compound is used as the host material of the light-emitting layer of the OLED device, and the prepared OLED device has a lower driving voltage, a higher current efficiency and a longer lifespan.

[0015] In the present invention, C6-C40 can be C6, C8, C10, C12, C16, C20, C24, C28, C30, C32, C36 or C40, etc.

[0016] C6-C30 can be C6, C8, C10, C12, C16, C20, C24, C28 or C30, etc.

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

[0018] C1-C12 can be C1, C2, C3, C4, C5, C6, C7, C8, C9, C10, C11 or C12.

[0019] It should be noted that in the present invention, "D" represents a deuterium atom, and where not separately indicated in the present invention, H and hydrogen therein both represent "protium". The same applies hereinafter.

[0020] The following are the 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.

[0021] As a preferred technical solution of the present invention, the C6-C40 aryl is selected from any one or a combination of at least two of phenyl, biphenyl, terphenyl, naphthyl, anthryl, phenanthryl, fluorenyl, benzofluorenyl, dibenzofluorenyl, naphthofluorenyl, pyrenyl, perylenyl, spirofluorenyl, triphenylene, fluoranthenyl, hydrobenzanthryl, indeno[1,2-b]fluorene, benzo[ghi]fluorene, dibenzo[ghi]fluorene, naphtho[2,3-b]fluorene, triphenylmethane, triphenylsilane or benzonaphtho[2,3-b]fluorene.

[0022] As a preferred technical solution of the present invention, the C6-C30 heteroaryl group is selected from any one or a combination of at least two of a carbazolyl group, a dibenzothiophenyl group, a dibenzofuranyl group, a naphthobenzofuranyl group, a naphthobenzothiophenyl group, a dinaphthofuranyl group, and a dinaphthothiophenyl group.

[0023] Preferably, the C6-C20 aryl group is selected from any one of a phenyl group, a naphthyl group, a biphenyl group, an anthryl group, a phenanthryl group, a fluorenyl group, a triphenylenyl group, or a fluoranthenyl group.

[0024] Preferably, the C1-C12 alkyl group is selected from any one of a methyl group, an ethyl group, a propyl group, a n-butyl group, a tert-butyl group, a cyclopentyl group, a cyclohexyl group, an octyl group, and an adamantyl group.

[0025] Preferably, the C1-C12 alkoxy group is selected from any one of a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentyloxy group, a hexyloxy group, and an octyloxy group.

[0026] As a preferred technical solution of the present invention, L is selected from any one of a single bond, a phenylene group, a dibenzofuranylene group, and a carbazolylene group.

[0027] Preferably, L is selected from a single bond.

[0028] Preferably, L is selected from a phenylene group.

[0029] Preferably, L is selected from a carbazolylene group.

[0030] As a preferred technical solution of the present invention, Ar1, Ar2, Ar3, and Ar4 are each independently selected from at least one of a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a triphenylenyl group, a fluoranthenyl group, an anthryl group, a phenanthryl group, a 9,9-dimethylfluorenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a fluorenyl group, and a carbazolyl group.

[0031] As a preferred technical solution of the present invention, Ar1 and Ar2 are each independently selected from at least one of a phenyl group, a biphenyl group, a naphthyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a fluorenyl group, and a carbazolyl group.

[0032] Preferably, Ar1 and Ar2 are each independently selected from at least one of a phenyl group, a biphenyl group, and a naphthyl group.

[0033] As a preferred technical solution of the present invention, Ar3 and Ar4 are each independently selected from at least one of a phenyl group, a biphenyl group, a naphthyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a fluorenyl group, and a carbazolyl group;

[0034] Each of the hydrogen atoms in Ar1 and Ar2 may independently be substituted by at least one of -F, -CN, methyl, ethyl, propyl, tert-butyl, methoxy, ethoxy, propoxy, phenyl, naphthyl, dibenzofuranyl, dibenzothiophenyl, carbazolyl, and triphenylsilyl.

[0035] As a preferred technical solution of the present invention, A, B, and C are all selected from N atoms.

[0036] Preferably, A and C are both selected from N atoms, and B is selected from CH.

[0037] Preferably, A is selected from N atoms, and B and C are both selected from CH.

[0038] Preferably, A and B are both selected from N atoms, and C is selected from CH.

[0039] As a preferred technical solution of the present invention, the carbazole compound is selected from any one of the following substituted or unsubstituted compounds:

[0040]

[0041]

[0042]

[0043] The substitution means that each of the hydrogen atoms in the above carbazole compound may independently be replaced by a deuterium atom. Preferably, the carbazole compound is selected from any one of the following compounds:

[0044]

[0045]

[0046] It should be noted that in the present invention, there is no special limitation on the preparation method of the above carbazole compound, and any common preparation method in the art is applicable.

[0047] In a second aspect, the present invention provides an intermediate, and the intermediate includes the following compound:

[0048]

[0049] wherein, Ar1 and Ar2 have the same definitions as above;

[0050] X1 is selected from any one of -F, -Cl, -Br, and -I;

[0051] Each of the hydrogen atoms in the intermediate may independently be replaced by a deuterium atom;

[0052] The intermediate does not include the following compound:

[0053]

[0054] The intermediate is used for preparing the carbazole compounds as described in the first aspect.

[0055] As a preferred technical solution of the present invention, the intermediate includes the following compounds:

[0056]

[0057] Similarly, it should be noted that the present invention has no special restrictions on the synthesis method of the intermediate, and the commonly used synthesis methods in the art are applicable.

[0058] Taking the synthesis method of the intermediate compound MA of the present invention as an example, it includes the following steps:

[0059]

[0060] Wherein, X1 and X2 are each independently selected from any one of -F, -Cl, -Br, and -I;

[0061] Ar1 and Ar2 have the same definitions as above.

[0062] The hydrogen atoms in the above raw materials and the intermediate compound MA can each independently be replaced by deuterium atoms (-D).

[0063] 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;

[0064] The material of the organic thin film layer includes the carbazole compounds as described in the first aspect.

[0065] Preferably, the organic thin film layer includes a light-emitting layer, and the host material of the light-emitting layer includes the carbazole compounds as described in the first aspect.

[0066] Preferably, the light-emitting layer is a phosphorescent light-emitting layer.

[0067] As a preferred technical solution of the present invention, the organic electroluminescent device is a blue organic electroluminescent device.

[0068] As a preferred technical solution of the present invention, the organic electroluminescent device is a green organic electroluminescent device.

[0069] In the present invention, the light-emitting layer includes a light-emitting layer host material and a doping material, wherein 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.

[0070] 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, a yellow phosphorescent light-emitting layer, and a blue phosphorescent light-emitting layer.

[0071] The volume percentage content of the host material in the phosphorescent light-emitting layer is 60% to 99.9% (for example, it can be 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98% or 99.9%, etc.), preferably 70% to 99.5%, and further preferably 85% to 95%.

[0072] In the present invention, the doping material of the light-emitting layer can be selected from phosphorescent light-emitting materials. The phosphorescent light-emitting materials, also known as triplet light-emitting materials, refer to the light emitted by substances from the triplet excited state. In the present invention, no special limitation is made on the specific selection of the phosphorescent materials, and the doping materials of the light-emitting layer commonly used in the art are all applicable. Exemplarily, it includes but is not limited to: compounds having a structure shown by formula PD:

[0073]

[0074] Among them, M is selected from any one of Ir, Pt, Pd, Os, Ti, Zr, Hf, Eu, Tb, Tm, Cu or Au;

[0075] Y1 - Y4 are each independently selected from carbon or nitrogen;

[0076] Y1 and Y2 can be connected by a single bond or a double bond, and Y3 and Y4 can be connected by a single bond or a double bond;

[0077] Cy1 and Cy2 are each independently 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, benzimidazolazolyl, benzazolyl, triazolyl, tetrazolyl, dioxazolyl, triazinyl, dibenzofuryl, dibenzothienyl, N-heterocarbazolyl, N-heterodibenzofuryl, and Cy1 and Cy2 can optionally be connected to each other via a single bond or an organic linking group;

[0078] 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 structural form conforming to chemical principles;

[0079] R 91 and R 92Each independently 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, -SF5, 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.

[0080] a1 and a2 are each independently an integer selected from 1-5, such as 1, 2, 3, 4 or 5;

[0081] b is an integer selected from 0-4, such as 0, 1, 2, 3 or 4;

[0082] a is selected from 1, 2 or 3;

[0083] L1 is a monovalent organic ligand, a divalent organic ligand or a trivalent organic ligand.

[0084] Preferably, the PD compound of the formula is selected from any one of the following compounds:

[0085]

[0086]

[0087]

[0088]

[0089]

[0090]

[0091] 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.

[0092] 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 toward 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 -0.2 V, preferably greater than -0.1 eV, more preferably greater than 0 eV, more preferably greater than 0.1 eV, and further preferably greater than 0.2 eV.

[0093] The P-type dopant exists in the hole injection layer in a volume percentage of 1% to 10% (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 or the compounds shown as HI-1 to HI-9 described below can be selected:

[0094]

[0095]

[0096] 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:

[0097]

[0098] Among them, 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.), and a heteroaryl group having 6 to 20 carbon atoms (for example, it can be C6, C8, C10, C12, C16, or C20, etc.);

[0099] Ar 41 、Ar42 Each independently selected from C6-C40 (such as C6, C8, C10, C12, C16, C20, C24, C28, C30, C32, C36 or C40, etc.) aryl, C6-C20 (such as C6, C8, C10, C12, C16 or C20, etc.) heteroaryl;

[0100] X is selected from CR 41 R 42 or NR 43 , wherein R 41 , R 42 , R 43 Each independently selected from substituted or unsubstituted phenyl (the substituents of the substituted phenyl are selected from C1-C6 (such as C1, C2, C3, C4, C5 or C6) alkyl, C1-C6 (such as C1, C2, C3, C4, C5 or C6) alkoxy, dibenzofuranyl), naphthyl, triphenylene, fluoranthenyl, 9,9-dimethylfluorenyl, biphenyl, substituted or unsubstituted dibenzofuranyl (the substituents of the substituted dibenzofuranyl are phenyl), substituted or unsubstituted dibenzothiophenyl (the substituents of the substituted dibenzothiophenyl are phenyl), dibenzofuran-substituted thiophenyl, any one of C1-C6 (such as C1, C2, C3, C4, C5 or C6) alkyl, R 41 , R 42 can be connected into a ring through a single bond.

[0101] In the present invention, the hole layer material (including the hole injection layer, the hole transport layer and the electron blocking layer) further includes a compound having the structure shown in Formula IA or a compound having the structure shown in Formula IB:

[0102]

[0103] Wherein, L is selected from any one of C6-C40 (such as C6, C8, C10, C12, C16, C20, C24, C28, C30, C32, C36 or C40, etc.) arylene, arylenedibenzofuranyl or arylenedibenzothiophenyl;

[0104] m is an integer between 0 and 4 (such as 0, 1, 2, 3 or 4), and n is selected from 0 or 1;

[0105] Ar is selected from any one of aryltriphenylene, arylfluoranthenyl, arylenedibenzofuranyl or arylenedibenzothiophenyl;

[0106] Ar1 and Ar2 are each independently selected from any one of aryl groups containing C6-C40 (such as C6, C8, C10, C12, C16, C20, C24, C28, C30, C32, C36 or C40, etc.), dibenzofuranyl or dibenzothiophenyl;

[0107] Independently of each other, the groups between Ar1 and Ar, between Ar2 and Ar, and between Ar1 and Ar2 can be connected or bridged by a single bond, O, S, CR1R2, NR.

[0108] R, R1, and R2 are each independently selected from any one of C1-C20 alkyl groups (such as C1, C2, C4, C6, C8, C10, C12, C14, C16, C18 or C20, etc.), C6-C40 aryl groups (such as C6, C8, C10, C12, C16, C20, C24, C28, C30, C32, C36 or C40, etc.), dibenzofuranyl or dibenzothiophenyl;

[0109] The hydrogen atoms in the compound of formula IB and the compound of formula IA can each independently be replaced by at least one of -F, -CN, -D (deuterium atom), C1-C6 alkyl group, C1-C6 alkoxy group, phenyl group, biphenyl group, naphthyl group, phenanthryl group, anthracenyl group, fluorenyl group, benzo[a]fluorenyl group, dibenzo[a,h]fluorenyl group, triphenylenyl group, fluoranthenyl group, pyrenyl group, perylenyl group, spirofluorene group, indeno[a]fluorenyl group or hydrogenated benzo[a]anthracenyl group.

[0110] Preferably, Ar is a fluoranthenylidene group, and m + n > 1.

[0111] 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 group (such as methyl, ethyl or propyl), C1-C3 alkoxy group (such as methoxy, ethoxy or propoxy), phenyl group, biphenyl group, triphenylenyl group, fluoranthenyl group.

[0112] Preferably, L, Ar1, and Ar2 are each independently selected from at least one of phenyl group, biphenyl group, naphthyl group, phenanthryl group, anthracenyl group, fluorenyl group, benzo[a]fluorenyl group, dibenzo[a,h]fluorenyl group, triphenylenyl group, fluoranthenyl group, pyrenyl group, perylenyl group, spirofluorene group, indeno[a]fluorenyl group or hydrogenated benzo[a]anthracenyl group.

[0113] Preferably, the compound of formula IB is selected from any one of the following compounds:

[0114]

[0115]

[0116] In the OLED device provided by the present invention, in addition to the compounds represented by formula HT-GH4, the compounds represented by formula IB, and the compounds represented by formula IA, the hole transport layer material may also include conventional hole materials in the art without particular limitation. Exemplarily, it includes but is not limited to: triarylamine compounds or carbazole compounds. Preferably, triarylamine compounds or carbazole compounds containing more than 3 N atoms are used, because triarylamine compounds or carbazole compounds containing more than 3 N atoms have a higher HOMO (smaller absolute value), and 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.

[0117] As the hole transport layer material, the triarylamine compound or carbazole compound has the following structure:

[0118]

[0119] 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;

[0120] And for Ar 601 ~Ar 609 wherein adjacent or connected to the same N atom, Ar 601 ~Ar 609 can be connected by a single bond or bridged by O, S, CR 701 R 702 , NR 703 ;

[0121] R 701 、R 702 、R 703 are selected from C6-C40 (such as C6, C8, C10, C12, C16, C20, C24, C28, C30, C32, C36 or C40, etc.) aromatic groups, C6-C20 (such as C6, C8, C10, C12, C16 or C20, etc.) heteroaromatic groups, C1-C6 (such as C1, C2, C3, C4, C5 or C6) alkyl groups, and R 701 、R702 It can be connected by a single key.

[0122] The hole blocking layer (HBL) can confine holes and / or excitons within the light-emitting layer range to improve the current efficiency and lifespan 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.

[0123] 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.

[0124] In the present invention, there is no special limitation on the electron transport layer material, and exemplary ones include but are not limited to:

[0125]

[0126]

[0127]

[0128]

[0129] 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 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.

[0130] It is also possible to select a thin intermediate layer introducing a material with a high dielectric constant 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, Li2O, BaF2, MgO, NaF, CsF, Cs2CO3, etc.) or lithium quinolate (LiQ) can be selected.

[0131] Compared with the prior art, the present invention has the following beneficial effects:

[0132] In the present invention, by designing the structure of the carbazole compound, a carbazole compound with excellent performance is prepared. Thus, the organic electroluminescent device prepared with the carbazole compound as the material of the light-emitting layer has a high current efficiency, a long lifespan, and a low driving voltage. Specific Embodiments

[0133] 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.

[0134] Preparation Example 1

[0135] This preparation example provides intermediate M2 and its synthesis method. The synthesis method is as follows:

[0136]

[0137] Under a nitrogen atmosphere, 80 mL of toluene, 40 mL of ethanol, and 25 mL of water were added to a 500 mL three-necked flask. Then, 1.6 g of compound 1,8-dibromocarbazole, 2.0 g of biphenyl-3-boronic acid, 2.12 g of sodium carbonate, and 0.23 g of tetrakis(triphenylphosphine)palladium were added thereto. The temperature was slowly raised to reflux for 9 h, cooled to room temperature, and water was added for liquid separation. After the organic layer was washed with water, it was dried with magnesium sulfate. After removing the desiccant, it was concentrated to dryness, and subjected to silica gel column chromatography separation, eluted with petroleum ether, to obtain intermediate M2 (1.6 g).

[0138] The obtained intermediate M2 was subjected to mass spectrometry detection, and the measured mass-to-charge ratio (m / z) was: 471.20.

[0139] Preparation Example 2

[0140] This preparation example provides intermediate M3 and its synthesis method. The synthesis method is as follows:

[0141]

[0142] (1) Synthesis of Intermediate M3-1

[0143] Under a nitrogen atmosphere, 80 mL of toluene, 40 mL of ethanol, and 25 mL of water were added to a three-necked flask. Then, 3.2 g of compound 1, 8-dibromocarbazole, 1.3 g of phenylboronic acid, 2.12 g of sodium carbonate, and 0.23 g of tetrakis(triphenylphosphine)palladium were added thereto. The temperature was slowly raised to reflux for 9 h, cooled to room temperature, water was added for liquid separation. After washing the organic layer with water, it was dried with magnesium sulfate. After removing the desiccant, it was concentrated to dryness, and subjected to silica gel column chromatography separation, eluted with petroleum ether to obtain intermediate M3-1 (2.6 g).

[0144] The obtained intermediate M3-1 was subjected to mass spectrometry detection, and the measured mass-to-charge ratio (m / z) was: 321.02.

[0145] (2) Synthesis of intermediate M3

[0146] With reference to the synthesis of intermediate M3-1, only the corresponding raw materials were used to prepare intermediate M3.

[0147] The obtained intermediate M3 was subjected to mass spectrometry detection, and the measured mass-to-charge ratio (m / z) was: 395.17.

[0148] Preparation Example 3

[0149] This preparation example provides intermediate M4 and its synthesis method. The synthesis method is as follows:

[0150]

[0151] With reference to the synthesis of intermediate M3, only the corresponding raw materials were used to prepare intermediate M4.

[0152] The obtained intermediate M4 was subjected to mass spectrometry detection, and the measured mass-to-charge ratio (m / z) was: 369.15.

[0153] Synthesis Example 1 Synthesis of Compound P1

[0154] This synthesis example provides compound P1 and its synthesis method. The synthesis method is as follows:

[0155]

[0156] Under a nitrogen atmosphere, 110 mL of dry toluene, 3.2 g of intermediate M1, 2.7 g of intermediate P1-1, Pd(dba)2 (bis(dibenzylideneacetonepalladium, 0.1 g), 0.8 g of 10% tri-tert-butylphosphine toluene solution by mass (the mass of tri-tert-butylphosphine is 0.08 g) and 1.2 g of sodium tert-butoxide were added to a three-necked flask, heated to 40°C for reaction for 4 hours, then heated to 70°C for reaction for 2 hours, and then reacted at reflux temperature for 6 hours, cooled to room temperature, water was added to separate, and the organic layer was washed with water until neutral, dried with magnesium sulfate, filtered to remove magnesium sulfate, concentrated to dryness, separated by silica gel column chromatography, and eluted with petroleum ether: dichloromethane = 10: 1 (volume ratio) to obtain compound P1 (3.0 g).

[0157] The mass spectrometry detection of compound P1: the mass-to-charge ratio (m / z) was measured to be 550.22.

[0158] Synthesis Example 2-9

[0159] Synthesis Examples 2-9 provide a compound and a synthesis method thereof, respectively. The synthesis method of the compound refers to the synthesis method of compound P1, and the corresponding raw material 1 and raw material 2 are reacted to prepare the corresponding compound, and the mass spectrum of the prepared compound is measured to record m / z. See Table 1 below for details:

[0160] Table 1

[0161]

[0162]

[0163] The synthesis of other compounds not listed can be carried out by referring to the above examples in combination with common knowledge in the art. The specific structures of some compounds used in the following application examples and comparative application examples are as follows:

[0164]

[0165]

[0166] Application Example 1

[0167] This application example provides a blue light organic electroluminescent device, using the compound P1 provided by the present invention as a main material of the light-emitting layer, and the structure of the blue light organic electroluminescent device is:

[0168] ITO / HT-1: HI-2 [5%] (80nm) / HT-1 (30nm) / EB-1 (20nm) / host material: PBD-1 [5%] (35nm) / ETL-1 (25nm) / LiF (0.5nm) / Al (150nm).

[0169] The preparation method of the blue light organic electroluminescent device is as follows:

[0170] Place the materials in a vacuum chamber and evacuate to 1×10 -5 ~1×10 -6 Pa, and then vacuum deposit the above materials onto the cleaned ITO substrate in sequence to prepare the OLED device.

[0171] Among them, PBD-1[5%] refers to the doping ratio of the dye, that is, the volume ratio of the host material to the dye PBD-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, and HT-1 is a hole transport material; HT-1:HI-2[5%] is used as the hole injection layer material, and EB-1 is the electron blocking layer material.

[0172] Application Example 2-9

[0173] Application Examples 2-9 respectively provide a blue light organic electroluminescent device, which is only different from Application Example 1 in that the host material compound P1 of the light-emitting layer is replaced by other compounds (see Table 2 below), and other preparation steps and conditions are the same as those in Application Example 1.

[0174] Comparative Application Example 1

[0175] Comparative Application Example 1 provides an organic electroluminescent device, which is only different from Application Example 1 in that the host material compound P1 of the light-emitting layer is replaced by other compounds (see Table 2 below), and other preparation steps and conditions are the same as those in Application Example 1.

[0176] Performance Test

[0177] Test the brightness, driving voltage, current efficiency and LT95 of the organic electroluminescent devices provided above. Among them, the current efficiency is the value corresponding to a brightness of 1000 cd / m 2 , 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 voltage, current efficiency and LT95 are relative values. The specific test results are shown in Table 2 below:

[0178] Table 2

[0179] Host material Dye <![CDATA[Luminance / (cd / m 2 )]]> Driving voltage Current efficiency LT95 Application Example 1 P1 PBD-1 1000 0.98 1.09 1.13 Application Example 2 P2 PBD-1 1000 1.00 1.06 1.15 Application Example 3 P3 PBD-1 1000 0.96 1.04 1.17 Application Example 4 P4 PBD-1 1000 0.92 1.16 1.04 Application Example 5 P5 PBD-1 1000 0.92 1.12 1.29 Application Example 6 P7 PBD-1 1000 0.80 1.01 1.02 Application Example 7 P8 PBD-1 1000 0.81 1.02 1.01 Application Example 8 P9 PBD-1 1000 0.99 1.09 1.47 Application Example 9 P10 PBD-1 1000 0.96 1.05 1.09 Comparative Application Example 1 D2 PBD-1 1000 1 1 1

[0180] As can be seen from the above, the structure of the carbazole compound in the present invention is designed such that there are two aryl substituents at the ortho position of the N atom of carbazole. The relatively large steric hindrance increases the degree of twisting of the material and the rigidity of the molecular structure, improving the film-forming property of the material. Therefore, the organic electroluminescent device prepared with the carbazole compound as the material of the light-emitting layer has a high current efficiency, a long lifespan, and a low driving voltage.

[0181] Comparing with the compound used in Application Example 1, which has four substituents on the carbazole ring, it causes great changes in the energy level and film-forming property of the material, and the performance of the prepared organic electroluminescent device becomes worse.

[0182] Application Example 10, Comparative Application Example 2

[0183] Application Example 10 and Comparative Application Example 2 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 below), and other preparation steps and conditions are the same as those in Application Example 1.

[0184] Performance Test

[0185] Test the brightness, driving voltage, current efficiency, and LT95 of the organic electroluminescent devices provided above. Among them, the current efficiency is the value corresponding to a brightness of 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 voltage, current efficiency, and LT95 are relative values. The specific test results are shown in Table 3 below:

[0186] Table 3

[0187] Host material Dye <![CDATA[Luminance / (cd / m 2 )]]> Driving voltage Current efficiency LT95 Application Example 10 P6 PBD-1 1000 0.90 1.01 1.11 Comparative Application Example 2 D3 PBD-1 1000 1 1 1

[0188] As can be seen from the above, the structure of the carbazole compound in the present invention is designed such that when Ar3 or Ar4 is selected from carbazole, the sp 2 hybridized carbon atoms on carbazole participate in the connection, and the prepared organic electroluminescent device has a high current efficiency, a long lifespan, and a low driving voltage.

[0189] Application Examples 11 - 15, Comparative Application Examples 3 - 4

[0190] Application Examples 11 - 15 and Comparative Application Examples 3 - 4 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 4 below), and other preparation steps and conditions are the same as those in Application Example 1.

[0191] Performance Test

[0192] The brightness, driving voltage, current efficiency, and LT95 of the organic electroluminescent device provided above are tested. Among them, the current efficiency is the value corresponding to a brightness of 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. The voltage, current efficiency, and LT95 are relative values. The specific test results are shown in Table 4 below:

[0193] Table 4

[0194] Host material Dye <![CDATA[Luminance / (cd / m 2 )]]> Driving voltage Current efficiency LT95 Application Example 11 P11 PBD-1 1000 0.99 1.01 1.22 Application Example 12 P12 PBD-1 1000 0.98 1.45 1.09 Application Example 13 P13 PBD-1 1000 0.92 1.78 1.02 Application Example 14 P14 PBD-1 1000 1.02 1.09 1.11 Application Example 15 P15 PBD-1 1000 1.03 1.11 1.02 Comparative Application Example 3 D4 PBD-1 1000 1 1 1 Comparative Application Example 4 D5 PBD-1 1000 1.03 0.86 1.01

[0195] Application Example 16, Comparative Application Example 5

[0196] Application Example 16 and Comparative Application Example 5 respectively provide a green organic electroluminescent device, which is only different from Application Example 1 in that the host material compound P1 of the light-emitting layer is replaced with other compounds (see Table 5 below in detail), and other preparation steps and conditions are the same as those in Application Example 1.

[0197] Performance Test

[0198] The brightness, driving voltage, current efficiency, and LT95 of the organic electroluminescent device provided above are tested. Among them, the current efficiency is the value corresponding to a brightness of 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. The voltage, current efficiency, and LT95 are relative values. The specific test results are shown in Table 5 below:

[0199] Table 5

[0200] Host material Dye <![CDATA[Luminance / (cd / m 2 )]]> Driving voltage Current efficiency LT95 Application Example 16 P16 PBD-1 1000 0.93 1.01 1.02 Comparative Application Example 5 D1 PBD-1 1000 1 1 1

[0201] In summary, the structure of the carbazole-based compound in the present invention is designed to obtain a carbazole-based compound with excellent performance. Therefore, the organic electroluminescent device prepared with the carbazole-based compound as the material of the light-emitting layer has a high current efficiency, a long lifespan, and a low driving voltage.

[0202] The applicant declares that the detailed process flow of the present invention is illustrated by the above embodiments, but the present invention is not limited to the above detailed process flow, that is, it does not mean that the present invention must rely on the above detailed process flow to be implemented. Those skilled in the art should understand that any improvement to the present invention, the equivalent substitution of each raw material of the present invention's product, the addition of auxiliary components, the selection of specific methods, etc., all fall within the protection scope and the disclosure scope of the present invention.

Claims

1. A carbazole compound, characterized in that, The carbazole compound has the structure shown in the following formula I: Wherein, Ar1 and Ar2 each independently selected from C6-C40 aryl; L is selected from any one of a single bond, C6-C40 arylene, dibenzofuranyl, carbazolyl, dibenzothiophenyl, 9,9-dimethylfluorenyl; A, B, and C each independently selected from an N atom or CH, and at least one of A, B, and C is selected from an N atom; Ar3 and Ar4 are each independently selected from any one of C6-C40 aryl and C6-C30 heteroaryl, and when Ar3 and Ar4 are selected from C6-C30 heteroaryl, the linking site of the C6-C30 heteroaryl is a sp 2 hybridized C atom; The hydrogen atoms in Ar3 and Ar4 can each independently be substituted by at least one of -F, -CN, C6-C20 aryl, C6-C30 heteroaryl, trityl, triphenylsilyl, C1-C12 alkyl or C1-C12 alkoxy; The hydrogen atoms in the compound of formula I can each independently be substituted by deuterium.

2. The carbazole compound according to claim 1, characterized in that, The C6-C40 aryl is selected from any one of phenyl, biphenyl, terphenyl, naphthyl, anthracenyl, phenanthryl, fluorenyl, benzofluorenyl, dibenzofluorenyl, naphthofluorenyl, pyrenyl, perylenyl, spirofluorene, triphenylene, fluoranthenyl, hydrobenzanthracenyl, indeno[1,2-b]fluorene, benzo[ghi]fluorene, dibenzo[ghi]fluorene, naphtho[2,1-a]fluorene, tritylmethane, triphenylsilyl or benzo[naphtho[2,1-a]fluorene], or a combination of at least two of them; Preferably, the C6-C30 heteroaryl is selected from any one of carbazolyl, dibenzothiophenyl, dibenzofuranyl, naphthobenzofuranyl, naphthobenzothiophenyl, dinaphthofuranyl, dinaphthothiophenyl, or a combination of at least two of them; Preferably, the C6-C20 aryl is selected from any one of phenyl, naphthyl, biphenyl, anthracenyl, phenanthryl, fluorenyl, triphenylene or fluoranthenyl; Preferably, the C1-C12 alkyl is selected from any one of methyl, ethyl, propyl, n-butyl, tert-butyl, cyclopentyl, cyclohexyl, octyl, adamantyl; Preferably, the C1-C12 alkoxy is selected from any one of methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy, octyloxy.

3. The carbazole compound according to claim 1 or 2, characterized in that, The L is selected from any one of a single bond, phenylene, dibenzofuranyl, carbazolyl; Preferably, the L is selected from a single bond; Preferably, the L is selected from phenylene; Preferably, the L is selected from carbazolyl.

4. The carbazole compound according to any one of claims 1-3, characterized in that The Ar1, Ar2, Ar3, and Ar4 each independently selected from at least one of phenyl, biphenyl, terphenyl, naphthyl, triphenylene, fluoranthenyl, anthracenyl, phenanthryl, 9,9-dimethylfluorenyl, dibenzofuranyl, dibenzothiophenyl, fluorenyl, carbazolyl; Preferably, the Ar1 and Ar2 each independently selected from at least one of phenyl, biphenyl, naphthyl, dibenzofuranyl, dibenzothiophenyl, fluorenyl, carbazolyl; Preferably, the Ar1 and Ar2 each independently selected from at least one of phenyl, biphenyl, naphthyl; Preferably, the Ar3 and Ar4 each independently selected from at least one of phenyl, biphenyl, naphthyl, dibenzofuranyl, dibenzothiophenyl, fluorenyl, carbazolyl; Each of the hydrogen atoms in Ar1 and Ar2 may be independently substituted by at least one of -F, -CN, methyl, ethyl, propyl, tert-butyl, methoxy, ethoxy, propoxy, phenyl, naphthyl, dibenzofuranyl, dibenzothiophenyl, carbazolyl, and triphenylsilyl.

5. The carbazole compound according to any one of claims 1-4, characterized in that, A, B, and C are each independently selected from N atoms; Preferably, both A and C are selected from N atoms, and B is selected from CH; Preferably, A is selected from N atoms, and both B and C are selected from CH; Preferably, both A and B are selected from N atoms, and C is selected from CH.

6. The carbazole compound according to any one of claims 1-5, characterized in that, The carbazole compound is selected from any one of the following substituted or unsubstituted compounds: The substitution means that each of the hydrogen atoms in the above carbazole compound may be independently replaced by a deuterium atom.

7. An intermediate, characterized in that, The intermediate includes the following compounds: Wherein, Ar1 and Ar2 have the same definitions as in claim 1; X1 is selected from any one of -F, -Cl, -Br, and -I; Each of the hydrogen atoms in the intermediate may be independently replaced by a deuterium atom; The intermediate does not include the following compounds: The intermediate is used for preparing the carbazole compound according to any one of claims 1-6.

8. The intermediate according to claim 7, wherein The intermediate includes the following compounds:

9. An organic electroluminescent device, characterized in that, The organic electroluminescent device includes an anode, a cathode, and an organic thin film layer disposed between the anode and the cathode; The material of the organic thin film layer includes the carbazole compound according to any one of claims 1-6; Preferably, the organic thin film layer includes a light-emitting layer, and the host material of the light-emitting layer includes the carbazole compound according to any one of claims 1-6; Preferably, the light-emitting layer is a phosphorescent light-emitting layer.

10. The organic electroluminescent device according to claim 9, wherein The organic electroluminescent device is a blue organic electroluminescent device; Preferably, the organic electroluminescent device is a green organic electroluminescent device.

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