Carbazole compound and organic electroluminescent device

Abstract

The invention provides a carbazole compound and an organic electroluminescent device. The carbazole compound has a structure as shown in a formula I. By designing 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 and relatively long service life.

Description

Technical Field

[0001] The present invention belongs to the technical field of organic electroluminescent materials, and particularly relates to a carbazole compound 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 speeds, and lower driving voltages. Therefore, they have also been fully developed for use as light sources for flat panel displays (such as wall-mounted TVs, etc.), or as backlight units for displays, illuminators, billboards, etc.

[0003] The structure of an 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 and an organic electroluminescent device. The present invention designs the structure of the carbazole compound, and 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, Ar 1 is selected from a carbazolyl group;

[0009] Ar 2 and Ar 3 are each independently selected from any one or a combination of at least two of a phenyl group, a naphthyl group, a biphenyl group, a 9,9-dimethylfluorenyl group, a carbazolyl group, a dibenzofuranyl group, or a dibenzothiophenyl group;

[0010] Each hydrogen atom in the compound of formula I can independently be replaced by a deuterium atom (D), -F, -CN, C1-C12 alkyl, C1-C12 alkoxy, triphenylsilyl ( The dotted line represents the connection site, the same hereinafter), triphenylmethyl substituted by at least one of C6-C20 aryl or C6-C20 heteroaryl.

[0011] In the present invention, by designing the structure of carbazole compounds, carbazole compounds with excellent properties are prepared. This compound has relatively appropriate HOMO and LUMO energy levels, and has good film-forming properties of the molecule and strong charge transport ability. Therefore, the organic electroluminescent device prepared with the carbazole compound as the material of the light-emitting layer has high current efficiency, long life and low driving voltage.

[0012] In the present invention, C1-C12 can be C1, C2, C3, C4, C5, C6, C7, C8, C9 or C12.

[0013] C6-C20 can be C6, C10, C12, C15, C18 or C20, etc.

[0014] In the present invention, "D" represents a deuterium atom. If not separately marked in the present invention, H and hydrogen therein both represent "protium", the same hereinafter.

[0015] 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 purpose and beneficial effects of the present invention can be better achieved and realized.

[0016] As a preferred technical solution of the present invention, the C1-C12 alkyl 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.

[0017] Preferably, the C1-C12 alkoxy is selected from any one of methoxy, ethoxy, propoxy, butoxy, pentyloxy or hexyloxy.

[0018] Preferably, the C6-C20 aryl is selected from any one of phenyl, naphthyl, biphenyl or 9,9-dimethylfluorenyl.

[0019] Preferably, the C6-C20 heteroaryl is selected from any one of carbazolyl, dibenzofuranyl or dibenzothiophenyl.

[0020] As a preferred technical solution of the present invention, the Ar 2Selected from any one of phenyl, naphthyl, biphenyl or 9,9-dimethylfluorenyl, preferably phenyl.

[0021] As a preferred technical solution of the present invention, the Ar 3 Selected from any one of phenyl, naphthyl, biphenyl or 9,9-dimethylfluorenyl, preferably phenyl.

[0022] As a preferred technical solution of the present invention, each hydrogen atom in the compound of formula I can independently be at least one of deuterium atom (D), -F, -CN, methoxy, ethoxy, propoxy, methyl, ethyl, propyl, tert-butyl, phenyl, biphenyl, naphthyl, dibenzofuranyl, carbazolyl, triphenylsilyl.

[0023] Preferably, each hydrogen atom in the compound of formula I can independently be at least one of deuterium atom, -F, -CN, tert-butyl, phenyl or naphthyl.

[0024] As a preferred technical solution of the present invention, the carbazole compound is selected from any one of the following substituted or unsubstituted compounds:

[0025]

[0026]

[0027] 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:

[0028]

[0029]

[0030] It should be noted that in the present invention, there is no special limitation on the preparation method of the above carbazole compound, and the commonly used preparation methods in the art are applicable.

[0031] In a second 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;

[0032] The material of the organic thin film layer includes the carbazole compound as described in the first aspect.

[0033] Preferably, the organic thin film layer includes a light-emitting layer, and the host material of the light-emitting layer includes the carbazole compound as described in the first aspect.

[0034] Preferably, the light-emitting layer is a phosphorescent light-emitting layer.

[0035] As a preferred technical solution of the present invention, the organic electroluminescent device is a green organic electroluminescent device.

[0036] 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.

[0037] 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.

[0038] 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%.

[0039] In the present invention, the doping material of the light-emitting layer can be a phosphorescent light-emitting material. The phosphorescent light-emitting material is also called 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 the commonly used doping materials for the light-emitting layer in the art are applicable. Exemplarily, it includes but is not limited to: a compound having a structure shown by formula PD:

[0040]

[0041] Among them, M is selected from any one of Ir, Pt, Pd, Os, Ti, Zr, Hf, Eu, Tb, Tm, Cu or Au;

[0042] Y 1 -Y 4 Each independently is selected from carbon or nitrogen;

[0043] 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;

[0044] Cy 1 and Cy 2Each independently 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, benzofuranyl, benzothienyl, isobenzothienyl, benzimidazazolyl, benzoxazolyl, triazolyl, tetrazolyl, dioxolyl, triazinyl, dibenzofuranyl, dibenzothienyl, N-heterocarbazolyl, N-heterodibenzofuranyl, wherein Cy 1 and Cy 2 may optionally be connected to each other via a single bond or an organic linking group;

[0045] Between any two ligands of M, or between more than two ligands, they can be connected by a single bond or a double bond, or can be bridged by O or S, or can be connected by any chemical group or chemical structure to form a chemically reasonable structural form;

[0046] 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, 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.

[0047] a 1 and a 2 Each independently is an integer selected from 1-5, such as 1, 2, 3, 4 or 5;

[0048] b is selected from integers from 0-4, such as 0, 1, 2, 3 or 4;

[0049] a is selected from 1, 2 or 3;

[0050] L 1 is a monovalent organic ligand, a divalent organic ligand or a trivalent organic ligand.

[0051] Preferably, the PD compound of the formula is any one of the following compounds:

[0052]

[0053]

[0054]

[0055]

[0056]

[0057]

[0058] 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.

[0059] 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 -0.2 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.

[0060] 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:

[0061]

[0062]

[0063] 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:

[0064]

[0065] Among them, L 41 is selected from a single bond, an aryl group of C6-C40 (for example, it can be C6, C8, C10, C12, C16, C20, C24, C28, C30, C32, C36, or C40, etc.), and a heteroaryl group of C6-C20 (for example, it can be C6, C8, C10, C12, C16, or C20, etc.);

[0066] Ar 41 Ar 42Each 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;

[0067] X is selected from CR 41 R 42 or NR 43 , where R 41 , R 42 , R 43 Each independently selected from substituted or unsubstituted phenyl (the substituents of the substituted 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 are phenyl), substituted or unsubstituted dibenzothiophenyl (the substituents of the substituted 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.

[0068] 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:

[0069]

[0070] Among them, 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;

[0071] m is an integer between 0 and 4 (such as 0, 1, 2, 3 or 4), and n is selected from 0 or 1;

[0072] Ar is selected from any one of aryltriphenylene, arylfluoranthenyl, arylenedibenzofuranyl or arylenedibenzothiophenyl;

[0073] Ar 1 and Ar 2Each independently selected from any one of aryl, dibenzofuranyl or dibenzothiophenyl containing C6-C40 (such as C6, C8, C10, C12, C16, C20, C24, C28, C30, C32, C36 or C40, etc.);

[0074] Ar 1 Between and Ar, Ar 2 Between and Ar, and Ar 1 Ar, 2 Between each other can be independently connected or bridged by a single bond, O, S, CR 1 R 2 NR.

[0075] R, R 1 R, 2 Each independently selected from any one of 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;

[0076] 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, C1-C6 alkoxy, phenyl, biphenyl, naphthyl, phenanthryl, anthryl, fluorenyl, benzo[a]fluorenyl, dibenzo[a,h]fluorenyl, triphenylene, fluoranthenyl, pyrenyl, perylenyl, spirofluorene, indeno[1,2-b]fluorene or hydrogenated benz[a]anthracenyl.

[0077] Preferably, the Ar is fluoranthenylene, and m + n > 1.

[0078] 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.

[0079] Preferably, the L, Ar 1 Ar, 2 Each independently selected from at least one of phenyl, biphenyl, naphthyl, phenanthryl, anthryl, fluorenyl, benzo[a]fluorenyl, dibenzo[a,h]fluorenyl, triphenylene, fluoranthenyl, pyrenyl, perylenyl, spirofluorene, indeno[1,2-b]fluorene or hydrogenated benz[a]anthracenyl.

[0080] Preferably, the compound of formula IB is selected from any one of the following compounds:

[0081]

[0082]

[0083] 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. Triarylamine compounds or carbazole compounds containing more than 3 N atoms are preferred 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.

[0084] As the hole transport layer material, the triarylamine compound or carbazole compound has the following structure:

[0085]

[0086] 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;

[0087] And Ar 601 ~Ar 609 in which the adjacent or Ar 601 ~Ar 609 connected to the same N atom can be connected by a single bond or bridged by O, S, CR 701 R 702 、NR 703 ;

[0088] R 701 、R 702 、R 703Selected 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.

[0089] 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.

[0090] 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.

[0091] In the present invention, there is no any special limitation on the electron transport layer material, and exemplary ones include but are not limited to:

[0092]

[0093]

[0094]

[0095]

[0096]

[0097]

[0098]

[0099] 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.

[0100] 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.

[0101] Compared with the prior art, the present invention has the following beneficial effects:

[0102] 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

[0103] 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.

[0104] Synthesis Example 1

[0105] This synthesis example provides compound P1 and its synthesis method, and the synthesis method is as follows:

[0106]

[0107] (1) Synthesis of Intermediate P1-1

[0108] 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, cooled to room temperature, water was added for liquid separation, the organic layer was washed with water, dried over magnesium sulfate, the desiccant was removed, concentrated to dryness, and subjected to silica gel column chromatography separation, eluted with petroleum ether to obtain intermediate P1-1 (3.7 g).

[0109] The obtained intermediate P1-1 was subjected to mass spectrometry detection, and the measured mass-to-charge ratio (m / z) was: 413.16.

[0110] (2) Synthesis of compound P1

[0111] Under nitrogen protection, 4.1 g of intermediate P1-1, 4.1 g of 9-phenyl-9H,9'H-3,3'-bicarbazole, 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 8 h, then raised to reflux for reaction for 3 h, cooled, water was added for filtration, the solid was dried under reduced pressure, and subjected to silica gel column chromatography separation, eluted with petroleum ether:ethyl acetate = 10:1 (volume ratio) to obtain compound P1 (3.1 g).

[0112] The obtained compound P1 was subjected to mass spectrometry detection, and the measured mass-to-charge ratio (m / z) was 801.31.

[0113] Synthesis Example 2

[0114] This synthesis example provides compound P2 and its synthesis method. The synthesis method is as follows:

[0115]

[0116] Referring to the synthesis of compound P1, compound P2 was prepared.

[0117] The obtained compound P2 was subjected to mass spectrometry detection, and the measured mass-to-charge ratio (m / z) was: 801.31.

[0118] Synthesis Example 3

[0119] This synthesis example provides compound P3 and its synthesis method. The synthesis method is as follows:

[0120]

[0121] Referring to the synthesis of compound P1, compound P3 was prepared.

[0122] The obtained compound P3 was subjected to mass spectrometry detection, and the measured mass-to-charge ratio (m / z) was: 801.31.

[0123] Synthesis Example 4

[0124] This synthesis example provides a synthesis method of compound P4, and the synthesis method is as follows:

[0125]

[0126] Under nitrogen protection, add 120 mL of dry toluene, 4.0 g of compound P4-1, 4.1 g of compound P4-2, and Pd(dba) into 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, and 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 12 hours, cooled to room temperature, added water to separate, and then the organic layer was washed with water until neutral, dried with magnesium sulfate, filtered to remove magnesium sulfate, concentrated to dryness, and crystallized from toluene to obtain compound P4 (4.7 g).

[0127] The obtained compound P4 was subjected to mass spectrometry detection, and the mass-to-charge ratio (m / z) was measured to be 730.31.

[0128] Synthesis Example 5

[0129] This synthesis example provides a synthesis method of compound P5, and the synthesis method is as follows:

[0130]

[0131] Referring to the synthesis of compound P4, compound P5 was prepared.

[0132] The obtained compound P5 was subjected to mass spectrometry detection, and the mass-to-charge ratio (m / z) was measured to be 837.41.

[0133] Other compounds whose specific synthesis methods are not listed can be synthesized by referring to the above embodiments in combination with common knowledge in the art.

[0134] The specific structures of some compounds used in the following application examples and comparative application examples are as follows:

[0135]

[0136]

[0137] Application Example 1

[0138] This application example provides a green 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 green light organic electroluminescent device is:

[0139] ITO / HT-1: HI-2[5%](80 nm) / HT-1(30 nm) / EB-1(20 nm) / Host material: PGD-1[5%](35 nm) / ETL-1(25 nm) / LiF(0.5 nm) / Al(150 nm).

[0140] The preparation method of the green organic electroluminescent device is as follows:

[0141] 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.

[0142] Among them, 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 to 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.

[0143] Application Example 2-3

[0144] Application Example 2-3 respectively provides 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 1 below), and other preparation steps and conditions are the same as those in Application Example 1.

[0145] Comparative Application Example 1

[0146] Comparative Application Example 1 provides 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 1 below), and other preparation steps and conditions are the same as those in Application Example 1.

[0147] Performance Test

[0148] Test the brightness, driving voltage, current efficiency and LT95 of the organic electroluminescent devices provided above. Among them, the current efficiency is the corresponding value when the brightness is 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 driving voltage, current efficiency and LT95 are relative values. The specific test results are shown in Table 1 below:

[0149] Table 1

[0150] Host material Dye <![CDATA[Luminance / (cd / m 2 )]]> Driving voltage Current efficiency LT95 Application Example 1 P1 PGD-1 1000 0.92 1.12 1.06 Application Example 2 P2 PGD-1 1000 0.98 1.20 1.03 Application Example 3 P3 PGD-1 1000 0.97 1.09 1.22 Comparative Application Example 1 DH2 PGD-1 1000 1 1 1

[0151] As can be seen from the above, 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 and a long lifespan.

[0152] Application Examples 4 - 5

[0153] Application Examples 4 - 5 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 2 below in detail), and other preparation steps and conditions are the same as those in Application Example 1.

[0154] Comparative Application Example 2

[0155] Comparative Application Example 2 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 (see Table 2 below in detail), and other preparation steps and conditions are the same as those in Application Example 1.

[0156] Performance Test

[0157] Test the luminance, driving voltage, current efficiency, and LT95 of the organic electroluminescent devices provided above. Among them, the current efficiency is the value corresponding to a luminance 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 driving voltage, current efficiency, and LT95 are relative values. The specific test results are shown in Table 2 below:

[0158] Table 2

[0159] Host material Dye <![CDATA[Luminance / (cd / m 2 )]]> Driving voltage Current efficiency LT95 Application Example 4 P4 PGD-1 1000 0.88 1.06 1.09 Application Example 5 P5 PGD-1 1000 0.96 1.02 1.31 Comparative Application Example 2 DH1 PGD-1 1000 1 1 1

[0160] As can be seen from the above, 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 and a long lifespan.

[0161] The applicant declares that the present invention uses the above embodiments to illustrate the detailed process flow of the present invention, 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 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 carbazole compound, characterized in that The carbazole compound has a structure shown in the following formula I: wherein Ar1 is selected from carbazole; Ar2 and Ar3 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 Ar2 is selected from any one of phenyl, naphthyl, biphenyl or 9,9-dimethylfluorenyl, preferably phenyl.

4. The carbazole compound according to any one of claims 1 to 3, characterized in that The Ar3 is selected from any one of phenyl, naphthyl, biphenyl or 9,9-dimethylfluorenyl, preferably phenyl.

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 (D), -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 each independently be replaced by at least one of a deuterium atom, -F, -CN, a tert-butyl 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. The carbazole compound according to any one of claims 1 to 6, characterized in that: The carbazole compound is selected from any one of the following compounds:

8. 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 7.

9. The organic electroluminescent device according to claim 8, characterized in that: The organic thin film layer comprises a light-emitting layer, and a main material of the light-emitting layer comprises the carbazole compound according to any one of claims 1 to 7.

10. The organic electroluminescent device according to claim 8, characterized in that: The light-emitting layer is a phosphorescent light-emitting layer; Preferably, the organic electroluminescent device is a green organic electroluminescent device.

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