Carbazole compound, intermediate and organic electroluminescent device

Abstract

The invention provides a carbazole compound, an intermediate and an organic electroluminescent device. The carbazole compound has a structure as shown in a formula I. Through the design of the carbazole compound, the carbazole compound with excellent performance is prepared, and the organic electroluminescent device prepared by taking the carbazole compound as a material of a luminescent 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 (e.g., liquid crystal display (LCD), plasma display panel (PDP), field emission display (FED), etc.), the organic electroluminescent device (OLED) has a simpler structure, various processing advantages, higher brightness, excellent viewing angle characteristics, faster response speed and lower driving voltage. Therefore, it has also been fully developed for use as a light source for flat panel displays (e.g., wall-mounted TV, etc.), or as a backlight unit for displays, illuminators, billboards, etc.

[0003] The structure of the organic electroluminescent device is specifically: an anode, a cathode and an organic layer therebetween. In order to improve the efficiency and stability of the organic electroluminescent element, the organic material layer includes multiple layers with different materials. In order 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 carbazole 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 higher current efficiency, a longer lifespan and a lower driving voltage.

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

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

[0007]

[0008] Wherein, Ar 1 、Ar 2 are each independently selected from any one or a combination of at least two of phenyl, naphthyl, biphenyl, 9,9-dimethylfluorenyl, carbazolyl, dibenzofuranyl or dibenzothiophenyl;

[0009] The hydrogen atoms in the compound of formula I can each independently be deuterium atoms (D), -F, -CN, C1-C12 alkyl, C1-C12 alkoxy, triphenylsilyl ( The dashed line indicates the connection site, the same hereinafter), triphenylmethyl Substituted by at least one of C6-C20 aryl or C6-C20 heteroaryl.

[0010] In the present invention, C1-C12 can be C1, C2, C3, C4, C5, C6, C7, C8, C9 or C12.

[0011] C6-C20 can be C6, C10, C12, C15, C18 or C20, etc.

[0012] In the present invention, "D" represents a deuterium atom. Where not separately indicated in the present invention, H and hydrogen therein both represent "protium", the same hereinafter.

[0013] 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.

[0014] 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, methylcyclopentyl, hexyl, methylcyclohexyl, heptyl, octyl or adamantyl, bicyclo[2.2.1]heptyl or bicyclo[2.2.2]octyl.

[0015] Preferably, the C1-C12 alkoxy group is selected from any one of methoxy, ethoxy, propoxy, butoxy, pentyloxy or hexyloxy.

[0016] Preferably, the C6-C20 aryl group is selected from any one of phenyl, naphthyl, biphenyl or 9,9-dimethylfluorenyl.

[0017] Preferably, the C6-C20 heteroaryl group is selected from any one of carbazolyl, dibenzofuranyl or dibenzothiophenyl.

[0018] As a preferred technical solution of the present invention, the Ar 1 is selected from any one of phenyl, naphthyl, biphenyl, dibenzofuranyl, dibenzothiophenyl, 9,9-dimethylfluorenyl, carbazolyl.

[0019] As a preferred technical solution of the present invention, the Ar 2 is selected from Ar 1 is selected from any one of phenyl, naphthyl, biphenyl, dibenzofuranyl, dibenzothiophenyl, 9,9-dimethylfluorenyl, carbazolyl.

[0020] As a preferred technical solution of the present invention, each hydrogen atom in the compound of formula I can independently be replaced by at least one of a deuterium atom (D), -F, -CN, methoxy, ethoxy, propoxy, methyl, ethyl, propyl, tert-butyl, phenyl, biphenyl, naphthyl, dibenzofuranyl, carbazolyl, and triphenylsilyl.

[0021] Preferably, each hydrogen atom in the compound of formula I can independently be replaced by at least one of a deuterium atom (D), -F, -CN, methyl, ethyl, propyl, tert-butyl, methoxy, ethoxy, propoxy, phenyl, or naphthyl.

[0022] As a preferred technical solution of the present invention, the carbazole compound is selected from any one of the following substituted or unsubstituted compounds:

[0023]

[0024]

[0025]

[0026] The substitution means that each hydrogen atom in the above carbazole compound can independently be replaced by a deuterium atom. Preferably, the carbazole compound is selected from any one of the following compounds:

[0027]

[0028]

[0029] It should be noted that in the present invention, there is no special limitation on the preparation method of the carbazole compound, and the commonly used preparation methods in the art are applicable.

[0030] In a second aspect, the present invention provides an intermediate, and the intermediate includes the following compounds:

[0031]

[0032] Among them, Ar 1 , Ar 2 has the same definition as above;

[0033] X 2 is selected from any one of F, Cl, Br, and I;

[0034] Each hydrogen atom in the compound of formula MA can independently be replaced by at least one of a deuterium atom (D), -F, -CN, C1-C12 alkyl, C1-C12 alkoxy, triphenylsilyl, triphenylmethyl, C6-C20 aryl, or C6-C20 heteroaryl.

[0035] The intermediate is used for preparing the carbazole compounds as described in the first aspect.

[0036] Preferably, the intermediate includes the following compounds:

[0037]

[0038] It should be noted that in the present invention, there is no special limitation on the preparation method of the intermediate, and the commonly used preparation methods in the art are applicable.

[0039] Illustrative examples of the preparation method of the intermediate provided by the present invention include the following steps:

[0040]

[0041] Among them, Ar 1 and Ar 2 have the same definitions as above;

[0042] X 1 and X 2 each independently selected from F, Cl, Br, I, and those skilled in the art can select the specific types of X 1 and X 2 according to common general knowledge;

[0043] The hydrogen atoms in the formula MA compound can each independently be substituted by at least one of deuterium atom, -F, -CN, C1-C12 alkyl, C1-C12 alkoxy, triphenylsilyl, triphenylmethyl, C6-C20 aryl or C6-C20 heteroaryl.

[0044] 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;

[0045] The material of the organic thin film layer includes the carbazole compounds as described in the first aspect.

[0046] 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.

[0047] Preferably, the light-emitting layer is a phosphorescent light-emitting layer.

[0048] As a preferred technical solution of the present invention, the organic electroluminescent device is a blue organic electroluminescent device.

[0049] 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.

[0050] 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.

[0051] 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%.

[0052] 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 applicable. Exemplarily, it includes but is not limited to: compounds having the structure shown in formula PD:

[0053]

[0054] Among them, M is selected from any one of Ir, Pt, Pd, Os, Ti, Zr, Hf, Eu, Tb, Tm, Cu or Au;

[0055] Y 1 -Y 4 Each independently is selected from carbon or nitrogen;

[0056] 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;

[0057] Cy 1 and Cy 2 Each independently is selected from 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 any one of them, and Cy 1 and Cy 2 can optionally be connected to each other via a single bond or an organic linking group;

[0058] Any two ligands of M, or more than two ligands, can be connected by single bonds or double bonds, or can be bridged by O or S, or can be connected by any chemical group or chemical structure to form a structural form that conforms to chemical principles;

[0059] R 91 and R 92 each independently selected from -H, -D, -F, -Cl, -Br, -I, hydroxyl, cyano, nitro, amino, amidino, hydrazino, hydrazono, carboxylic acid group, carboxylate group, sulfonic acid group, sulfonate group, phosphoric acid group, phosphate group, -SF 5 、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.

[0060] a 1 and a 2 each independently an integer selected from 1-5, such as 1, 2, 3, 4 or 5;

[0061] b is selected from integers 0-4, such as 0, 1, 2, 3 or 4;

[0062] a is selected from 1, 2 or 3;

[0063] L 1 is a monovalent organic ligand, a divalent organic ligand or a trivalent organic ligand.

[0064] Preferably, the PD compound of the formula is selected from any one of the following compounds:

[0065]

[0066]

[0067]

[0068]

[0069]

[0070]

[0071]

[0072] 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.

[0073] The material of the hole injection layer includes a P-type dopant. A P-type dopant refers to a substance that coexists with the material of the hole injection layer in the OLED device, can oxidize the material of the hole injection layer, and thus serves as an electron acceptor, which can promote 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, further preferably greater than 0 eV, further preferably greater than 0.1 eV, and further preferably greater than 0.2 eV.

[0074] 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 or the compounds shown as HI-1 to HI-9 described below can be selected:

[0075]

[0076]

[0077] 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:

[0078]

[0079] Among them, L 41 is selected from a single bond, an aryl group having 6 to 40 carbon atoms (such as 6, 8, 10, 12, 16, 20, 24, 28, 30, 32, 36 or 40 carbon atoms, etc.), or a heteroaryl group having 6 to 20 carbon atoms (such as 6, 8, 10, 12, 16 or 20 carbon atoms, etc.);

[0080] Ar 41 and Ar 42 are each independently selected from an aryl group having 6 to 40 carbon atoms (such as 6, 8, 10, 12, 16, 20, 24, 28, 30, 32, 36 or 40 carbon atoms, etc.), or a heteroaryl group having 6 to 20 carbon atoms (such as 6, 8, 10, 12, 16 or 20 carbon atoms, etc.);

[0081] X is selected from CR 41 R 42 or NR 43 wherein R 41 and R 42 and R 43 are each independently selected from a substituted or unsubstituted phenyl group (the substituents of the substituted phenyl group are selected from an alkyl group having 1 to 6 carbon atoms (such as 1, 2, 3, 4, 5 or 6 carbon atoms), an alkoxy group having 1 to 6 carbon atoms (such as 1, 2, 3, 4, 5 or 6 carbon atoms), dibenzofuranyl), naphthyl, triphenylene, fluoranthenyl, 9,9-dimethylfluorenyl, biphenyl, a substituted or unsubstituted dibenzofuranyl group (the substituent of the substituted dibenzofuranyl group is a phenyl group), a substituted or unsubstituted dibenzothiophenyl group (the substituent of the substituted dibenzothiophenyl group is a phenyl group), a dibenzofuran-substituted thiophenyl group, or an alkyl group having 1 to 6 carbon atoms (such as 1, 2, 3, 4, 5 or 6 carbon atoms), and R 41 and R 42 can be connected into a ring through a single bond.

[0082] 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 a structure shown in Formula IA or a compound having a structure shown in Formula IB as follows:

[0083]

[0084] Among them, L is selected from any one of an arylene group having 6 to 40 carbon atoms (such as 6, 8, 10, 12, 16, 20, 24, 28, 30, 32, 36 or 40 carbon atoms, etc.), a dihydrodibenzofuranyl group, or a dihydrodibenzothiophenyl group;

[0085] m is an integer selected from 0 to 4 (for example, it can be 0, 1, 2, 3, or 4), and n is selected from 0 or 1;

[0086] Ar is any one of anthrylene, fluoranthenylene, dibenzofuranylene, or dibenzothiophenylene;

[0087] Ar 1 and Ar 2 each independently is selected from any one of aryl containing C6-C40 (for example, it can be C6, C8, C10, C12, C16, C20, C24, C28, C30, C32, C36, or C40, etc.), dibenzofuranyl, or dibenzothiophenyl;

[0088] Ar 1 between Ar and Ar, between Ar 2 and Ar, and between Ar 1 and Ar 2 each independently can be connected or bridged by a single bond, O, S, CR 1 R 2 , NR.

[0089] R, R 1 and R 2 each independently is selected from any one of C1-C20 alkyl (for example, it can be C1, C2, C4, C6, C8, C10, C12, C14, C16, C18, or C20, etc.), aryl containing C6-C40 (for example, it can be C6, C8, C10, C12, C16, C20, C24, C28, C30, C32, C36, or C40, etc.), dibenzofuranyl, or dibenzothiophenyl;

[0090] The hydrogen atoms in the compound of formula IB and the compound of formula IA each independently can be replaced by at least one of -F, -CN, -D (deuterium atom), C1-C6 alkyl, C1-C6 alkoxy, phenyl, biphenyl, naphthyl, phenanthryl, anthryl, fluorenyl, benzofluorenyl, dibenzofluorenyl, anthrylene, fluoranthenyl, pyrenyl, perylenyl, spirofluorenyl, indenofluorenyl, or hydrogenated benzanthryl.

[0091] Preferably, the Ar is fluoranthenylene, and m + n > 1.

[0092] 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 (for example, it can be methyl, ethyl, or propyl), C1-C3 alkoxy (for example, it can be methoxy, ethoxy, or propoxy), phenyl, biphenyl, anthrylene, or fluoranthenyl.

[0093] Preferably, the L, Ar 1, Ar 2 Each independently selected from at least one of phenyl, biphenyl, naphthyl, phenanthryl, anthryl, fluorenyl, benzofluorenyl, dibenzofluorenyl, triphenylenyl, fluoranthenyl, pyrenyl, perylenyl, spirofluorene, indeno[1,2-b]fluorene or hydrogenated benzanthracenyl.

[0094] Preferably, the compound of Formula IB is selected from any one of the following compounds:

[0095]

[0096]

[0097] 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 transport layer material may also 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 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 higher LUMO, can also be used as electron blocking layer materials.

[0098] As the hole transport layer material, the triarylamine compound or carbazole compound has the following structure:

[0099]

[0100] Wherein, Ar 601 ~Ar 609 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, substituted or unsubstituted dibenzofuranyl, substituted or unsubstituted dibenzothiophenyl, substituted or unsubstituted naphthobenzofuranyl, substituted or unsubstituted naphthobenzothiophenyl, substituted or unsubstituted dinaphthofuranyl, substituted or unsubstituted dinaphthothiophenyl;

[0101] And Ar 601 ~Ar 609 Among them, Ar 601 ~Ar 609 adjacent or connected to the same N atom, can be connected by a single bond or through O, S, CR 701 R702 and NR 703 bridging;

[0102] R 701 and R 702 and R 703 are each independently 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 and R 702 may be connected by a single bond.

[0103] The hole blocking layer (HBL) can confine holes and / or excitons within the light-emitting layer 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.

[0104] 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.

[0105] In the present invention, there is no special limitation on the electron transport layer material, and exemplary ones include but are not limited to:

[0106]

[0107]

[0108]

[0109]

[0110]

[0111]

[0112]

[0113] 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.

[0114] 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.

[0115] Compared with the prior art, the present invention has the following beneficial effects:

[0116] In the present invention, by designing the structure of the carbazole compound, it is applicable 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. Specific Embodiments

[0117] 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.

[0118] Synthesis Example 1

[0119] This synthesis example provides compound P1 and its synthesis method, and the synthesis method is as follows:

[0120]

[0121] (1) Synthesis of Intermediate P1-1

[0122] Under a nitrogen atmosphere, 60 mL of toluene, 30 mL of ethanol, and 20 mL of water were added to a three-necked flask. Then, 3.2 g of compound 3-bromo-9-phenylcarbazole, 3.0 g of compound 3-phenyl-4-fluoro-phenylboronic acid pinacol ester, 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 6 h, then cooled to room temperature, 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 P1-1 (3.7 g).

[0123] The obtained intermediate P1-1 was subjected to mass spectrometry detection, and the measured mass-to-charge ratio (m / z) was: 413.16.

[0124] (2) Synthesis of compound P1

[0125] Under nitrogen protection, 4.1 g of intermediate P1-1, 1.7 g of carbazole, 6.1 g of cesium carbonate, and 90 mL of DMF were successively added to a three-necked flask. The temperature was raised to 100 °C for reaction for 4 h, then raised to reflux for reaction for 2 h, cooled, water was added for filtration, and a solid was precipitated. After the solid was dried under reduced pressure, it was subjected to silica gel column chromatography separation, eluted with petroleum ether:ethyl acetate = 10:1 (volume ratio), to obtain compound P1 (4.9 g).

[0126] The obtained compound P1 was subjected to mass spectrometry detection, and the measured mass-to-charge ratio (m / z) was 560.23.

[0127] Synthesis Example 2

[0128] This synthesis example provides compound P2 and its synthesis method. The synthesis method is as follows:

[0129]

[0130] (1) Synthesis of intermediate P2-1

[0131] Referring to the synthesis of intermediate P1-1, intermediate P2-1 was prepared.

[0132] The obtained intermediate P2-1 was subjected to mass spectrometry detection, and the measured mass-to-charge ratio (m / z) was: 463.17.

[0133] (2) Synthesis of compound P2

[0134] Referring to the synthesis of compound P1, compound P2 was prepared.

[0135] The obtained compound P2 was subjected to mass spectrometry detection, and the measured mass-to-charge ratio (m / z) was: 610.24.

[0136] Synthesis Example 3

[0137] This synthesis example provides compound P10 and its synthesis method, and the synthesis method is as follows:

[0138]

[0139] (1) Synthesis of intermediate P10-1

[0140] Referring to the synthesis of intermediate P1-1, intermediate P10-1 was prepared.

[0141] The obtained intermediate P10-1 was subjected to mass spectrometry detection, and the measured mass-to-charge ratio (m / z) was: 671.24.

[0142] (2) Synthesis of compound P10

[0143] Referring to the synthesis of compound P1, compound P10 was prepared.

[0144] The obtained compound P10 was subjected to mass spectrometry detection, and the measured mass-to-charge ratio (m / z) was: 818.31.

[0145] Synthesis example 4

[0146] This synthesis example provides compound P11 and its synthesis method, and the synthesis method is as follows:

[0147]

[0148] (1) Synthesis of intermediate P11-1

[0149] Referring to the synthesis of intermediate P1-1, intermediate P11-1 was prepared.

[0150] The obtained intermediate P11-1 was subjected to mass spectrometry detection, and the measured mass-to-charge ratio (m / z) was: 413.16.

[0151] (2) Synthesis of compound P11

[0152] Referring to the synthesis of compound P1, compound P11 was prepared.

[0153] The obtained compound P11 was subjected to mass spectrometry detection, and the measured mass-to-charge ratio (m / z) was: 560.23.

[0154] For compounds without specific synthesis methods listed, the above examples can be referred to and combined with the common general knowledge in the art for synthesis.

[0155] The specific structures of some compounds used in the following application examples and comparative application examples are as follows:

[0156]

[0157]

[0158] Application Example 1

[0159] This application example provides a blue organic electroluminescent device, using the compound P1 provided by the present invention as the host material of the light-emitting layer. The structure of the blue organic electroluminescent device is as follows:

[0160] 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).

[0161] The preparation method of the blue organic electroluminescent device is as follows:

[0162] Place the materials in a vacuum chamber, evacuate to 1×10 -5 ~1×10 -6 Pa, and sequentially vacuum deposit the above materials onto the cleaned ITO substrate to prepare the OLED device.

[0163] 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 an electron blocking layer material.

[0164] Application Examples 2-10

[0165] Application Examples 2-10 respectively provide a blue organic electroluminescent device. The difference from Application Example 1 is only that the host material compound P1 of the light-emitting layer is replaced by other compounds (see Table 1 below), and other preparation steps and conditions are the same as those in Application Example 1.

[0166] Comparative Application Examples 1-2

[0167] Comparative Application Examples 1-2 respectively provide a blue organic electroluminescent device. The difference from Application Example 1 is only that the host material compound P1 of the light-emitting layer is replaced by other compounds (see Table 1 below), and other preparation steps and conditions are the same as those in Application Example 1.

[0168] Performance Test

[0169] Test the brightness, driving voltage, current efficiency and LT95 of the organic electroluminescent devices provided above. Among them, the current efficiency is when the brightness is 1000 cd / m 2The corresponding value, LT95 refers to the time required for the device efficiency to drop to 95% of the efficiency corresponding to the initial current density of the device while keeping the initial current density of the device at 10 mA / cm², where the driving voltage, current efficiency, and LT95 are relative values. The specific test results are shown in Table 1 below: 2 remaining unchanged, where the driving voltage, current efficiency, and LT95 are relative values. The specific test results are shown in Table 1 below:

[0170] Table 1

[0171] Host material Dye <![CDATA[Luminance / (cd / m 2 )]]> Driving voltage Current efficiency LT95 Application Example 1 P1 PBD-1 1000 0.89 1.26 1.29 Application Example 2 P2 PBD-1 1000 0.83 1.16 1.17 Application Example 3 P3 PBD-1 1000 0.92 1.09 1.47 Application Example 4 P4 PBD-1 1000 0.88 1.29 1.32 Application Example 5 P5 PBD-1 1000 0.98 1.07 1.03 Application Example 6 P7 PBD-1 1000 0.92 1.39 1.18 Application Example 7 P8 PBD-1 1000 0.82 1.47 1.27 Application Example 8 P9 PBD-1 1000 0.88 1.55 1.20 Application Example 9 P10 PBD-1 1000 0.91 1.10 1.67 Application Example 10 P11 PBD-1 1000 0.87 1.16 1.37 Comparative Application Example 1 DH1 PBD-1 1000 1 1 1 Comparative Application Example 2 DH2 PBD-1 1000 1.02 0.91 0.90

[0172] In the present invention, by designing the structure of the carbazole compound, a carbazole compound with excellent performance is prepared. In this compound, a carbazole ring in which Ar2 and N are involved in bonding is respectively connected to the ortho - positions of the benzene ring. This Ar2 and the carbazole ring are ortho - substituted, with a large steric hindrance, resulting in a large molecular strain, which causes the molecular energy level to increase. Thus, its energy can be transferred to the dye more efficiently, and the molecule has good film - forming properties and strong charge - transporting ability. 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.

[0173] From the above content, it can be seen that in the present invention, by designing the structure of the carbazole compound, it is suitable as the host material of the light - emitting layer of the organic electroluminescent device, enabling the organic electroluminescent device to have a high current efficiency, a long lifespan, and a low driving voltage.

[0174] 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 substitution 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 carbazole compound, characterized in that: The carbazole compound has a structure shown in the following formula I: Wherein, Ar1 and Ar2 are each independently selected from any one or a combination of at least two of phenyl, naphthyl, biphenyl, 9,9-dimethylfluorenyl, carbazolyl, dibenzofuranyl or dibenzothiophenyl; The hydrogen atoms in the compound of formula I may be independently substituted by at least one of a deuterium atom, -F, -CN, a C1-C12 alkyl group, a C1-C12 alkoxy group, a triphenylsilyl group, a triphenylmethyl group, a C6-C20 aryl group or a C6-C20 heteroaryl group.

2. The carbazole compound according to claim 1, characterized in that The C1-C12 alkyl group is selected from any one of methyl, ethyl, propyl, butyl, pentyl, methylcyclopentyl, hexyl, methylcyclohexyl, heptyl, octyl or adamantyl, bicyclo[2.2.1]heptyl or bicyclo[2.2.2]octyl; Preferably, the C1-C12 alkoxy group is selected from any one of methoxy, ethoxy, propoxy, butoxy, pentyloxy or hexyloxy; Preferably, the C6-C20 aryl group is selected from any one of phenyl, naphthyl, biphenyl or 9,9-dimethylfluorenyl; Preferably, the C6-C20 heteroaryl group is selected from any one of a carbazolyl group, a dibenzofuranyl group or a dibenzothiophenyl group.

3. The carbazole compound according to claim 1 or 2, characterized in that The Ar1 is selected from any one of phenyl, naphthyl, biphenyl, dibenzofuranyl, dibenzothiophenyl, 9,9-dimethylfluorenyl and carbazole.

4. The carbazole compound according to any one of claims 1 to 3, characterized in that Ar2 is selected from any one of Ar1, which is selected from phenyl, naphthyl, biphenyl, dibenzofuranyl, dibenzothiophenyl, 9,9-dimethylfluorenyl, and carbazole.

5. The carbazole compound according to any one of claims 1 to 4, characterized in that The hydrogen atoms in the compound of formula I can be replaced by at least one of a deuterium atom, -F, -CN, a methoxy group, an ethoxy group, a propoxy group, a methyl group, an ethyl group, a propyl group, a tert-butyl group, a phenyl group, a biphenyl group, a naphthyl group, a dibenzofuranyl group, a carbazolyl group, and a triphenylsilyl group; Preferably, the hydrogen atoms in the compound of formula I can be replaced independently by at least one of a deuterium atom, -F, -CN, a methyl group, an ethyl group, a propyl group, a tert-butyl group, a methoxy group, an ethoxy group, a propoxy group, a phenyl group or a naphthyl group.

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

7. An intermediate, characterized in that The intermediates include the following compounds: Wherein, Ar1 and Ar2 have the same definitions as in claim 1; X2 is selected from any one of F, Cl, Br, and I; The hydrogen atoms in the compound of formula MA may each independently be substituted by at least one of a deuterium atom, -F, -CN, a C1-C12 alkyl group, a C1-C12 alkoxy group, a triphenylsilyl group, a triphenylmethyl group, a C6-C20 aryl group or a C6-C20 heteroaryl group; The intermediate is used to prepare the carbazole compound according to any one of claims 1 to 6.

8. The intermediate according to claim 7, characterized in that The intermediates include the following compounds:

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 material of the organic thin film layer includes the carbazole compound according to any one of claims 1 to 6.

10. The organic electroluminescent device according to claim 9, characterized in that: The organic thin film layer comprises a light-emitting layer, and the main material of the light-emitting layer comprises the carbazole compound according to any one of claims 1 to 6; Preferably, the light-emitting layer is a phosphorescent light-emitting layer; Preferably, the organic electroluminescent device is a blue organic electroluminescent device.

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