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. By designing the structure 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 the electron blocking layer has relatively low driving voltage, 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, an intermediate and an organic electroluminescent device. Background Art

[0002] Compared with other flat panel displays (e.g., 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 (e.g., 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, 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 electron blocking layer has a lower driving voltage, a higher current efficiency and a longer lifespan.

[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 is selected from any one of an H atom, an alkyl group with 1 - 10 carbon atoms, an alkoxy group with 1 - 10 carbon atoms, an aryl group with 6 - 20 carbon atoms, and a heteroaryl group with 5 - 20 carbon atoms; and when Ar is selected from a heteroaryl group with 5 - 20 carbon atoms, the connection site of Ar is a carbon atom in the heteroaryl group (that is, when Ar is selected from a heteroaryl group with 5 - 20 carbon atoms, the connection site of Ar is a carbon atom in the heteroaryl group, rather than a heteroatom in the heteroaryl group);

[0009] Each hydrogen atom in the compound of formula I can be independently substituted by at least one of deuterium atom (-D), -F, -CN, aryl group of C6-C20, and heteroaryl group of C5-C20;

[0010] The compound of formula I does not include compound D1 and compound D7:

[0011]

[0012] In the present invention, by designing the structure of the carbazole compound, a carbazole compound with excellent performance is prepared. This compound has relatively appropriate HOMO and LUMO energy levels, and has good film-forming property of the molecule and strong charge transport ability. Therefore, the organic electroluminescent device prepared with the carbazole compound as the material of the electron blocking layer has a lower driving voltage, a higher current efficiency and a longer lifespan.

[0013] In the present invention, C1-C10 can be C1, C2, C3, C4, C5, C6, C7, C8, C9 or C10.

[0014] C6-C20 can be C6, C8, C10, C12, C15, C18 or C20, etc.

[0015] C5-C20 can be C5, C7, C10, C12, C15, C18 or C20, etc.

[0016] It should be noted that in the present invention, unless otherwise specified, D is a deuterium atom, and H and hydrogen both refer to protium. The same applies hereinafter.

[0017] 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.

[0018] As a preferred technical solution of the present invention, the C1-C10 alkyl group is selected from any one of methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl or decyl, and is further preferably selected from any one of methyl, isopropyl, tert-butyl, methylcyclopentyl, methylcyclohexyl, adamantyl, bicyclo[2.2.1]heptyl or bicyclo[2.2.2]octyl.

[0019] Preferably, the C1-C10 alkoxy group is selected from any one of methoxy, ethoxy, propoxy, butoxy, cyclohexyloxy.

[0020] Preferably, the C6-C20 aryl group is selected from any one of phenyl, naphthyl, biphenyl, 9,9-dimethylfluorenyl.

[0021] Preferably, the C5-C20 heteroaryl is selected from any one of dibenzofuranyl, dibenzothiophenyl, carbazolyl, and pyridyl.

[0022] As a preferred technical solution of the present invention, Ar is selected from any one of a hydrogen atom, 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, a naphthyl group, a biphenyl group, a 9,9-dimethylfluorenyl group, a carbazolyl group, a dibenzofuranyl group, or a dibenzothiophenyl group.

[0023] Preferably, Ar is selected from any one of a hydrogen atom, a methyl group, a tert-butyl group, a methoxy group, a propoxy group, a phenyl group, a naphthyl group, a biphenyl group, a 9,9-dimethylfluorenyl group, a carbazolyl group, a dibenzofuranyl group, or a dibenzothiophenyl group.

[0024] As a preferred technical solution of the present invention, each hydrogen atom in the compound of formula I can independently be any one of a deuterium atom (-D), -F, -CN, a phenyl group, a naphthyl group, a biphenyl group, a 9,9-dimethylfluorenyl group, a carbazolyl group, a dibenzofuranyl group, or a dibenzothiophenyl group.

[0025] As a preferred technical solution of the present invention, the carbazole compound has any one of the structures shown in formulas I-1 to I-4 below:

[0026]

[0027] Among them, Ar has the same definition as above;

[0028] Each hydrogen atom in the compounds of formulas I-1 to I-4 can independently be substituted by at least one of a deuterium atom (D), -F, -CN, a C6-C20 aryl group, or a C5-C20 heteroaryl group.

[0029] As a preferred technical solution of the present invention, the carbazole compound is selected from any one of the following substituted or unsubstituted compounds:

[0030]

[0031]

[0032] The substitution means that each hydrogen atom in the above carbazole compound can independently be substituted by a deuterium atom. Preferably, the carbazole compound includes the following compounds:

[0033]

[0034] In the present invention, there are no special restrictions on the preparation method of the carbazole compound, and the commonly used preparation methods in the art are applicable.

[0035] Second aspect, the present invention provides an intermediate, which includes a compound having a structure shown in formula MH below and a compound having a structure shown in formula MXF below:

[0036]

[0037] Wherein, Ar has the same definition as above;

[0038] X 2 is independently selected from any one of -F, -Cl, -Br, and -I;

[0039] The hydrogen atoms in the compound of formula MH and the compound of formula MXF can each independently be substituted by at least one of deuterium atoms (-D), -F, -CN, aryl groups with 6 to 20 carbon atoms, and heteroaryl groups with 5 to 20 carbon atoms;

[0040] The intermediate does not include the following compounds:

[0041]

[0042] The intermediate is used for preparing the carbazole compounds as described in the first aspect.

[0043] As a preferred technical solution of the present invention, the intermediate includes the following compounds:

[0044]

[0045] It should be noted that the present invention does not have any special restrictions on the synthesis method of the intermediate, and the commonly used synthesis methods in the art are applicable. The synthesis method of the intermediate in the present invention is illustrated as follows:

[0046]

[0047] Wherein, Ar has the same definition as above;

[0048] X 1 and X 2 are each independently selected from any one of -F, -Cl, -Br, and -I.

[0049] 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;

[0050] The organic thin film layer includes the carbazole compounds as described in the first aspect.

[0051] As a preferred technical solution of 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.

[0052] Preferably, the organic thin film layer includes an electron blocking layer and a light emitting layer, and the material of the electron blocking layer includes a carbazole compound as described in the first aspect.

[0053] Preferably, the light emitting layer is a phosphorescent light emitting layer.

[0054] As a preferred technical solution of the present invention, the organic electroluminescent device is a blue organic electroluminescent device.

[0055] In the present invention, the light emitting layer includes a light emitting layer host material and a doping material. Among them, 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.

[0056] 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.

[0057] 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%.

[0058] 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 the triplet excited state. In the present invention, the specific selection of the phosphorescent material is not particularly limited, and the doping materials commonly used in the art for the light emitting layer are all applicable. Exemplarily, it includes but is not limited to: a compound having a structure represented by formula PD:

[0059]

[0060] Wherein, M is selected from any one of Ir, Pt, Pd, Os, Ti, Zr, Hf, Eu, Tb, Tm, Cu or Au;

[0061] Y 1 -Y 4 Each independently is selected from carbon or nitrogen;

[0062] 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;

[0063] 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, where Cy 1 and Cy 2 may optionally be connected to each other via a single bond or an organic linking group;

[0064] 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 chemically reasonable structural form;

[0065] 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.

[0066] a 1 and a 2 Each independently is an integer selected from 1-5, such as 1, 2, 3, 4 or 5; b is an integer selected from 0-4, such as 0, 1, 2, 3 or 4;

[0067] a is selected from 1, 2 or 3;

[0068] L 1 is a monovalent organic ligand, a divalent organic ligand or a trivalent organic ligand.

[0069] Preferably, the PD compound of the formula is any one of the following compounds:

[0070]

[0071]

[0072]

[0073]

[0074]

[0075]

[0076] In the present invention, the hole layer material (including the hole injection layer, the hole transport layer, and the electron blocking layer) may also have a structure represented by the following formula HT-GH4:

[0077]

[0078] Wherein, L 41 is selected from a single bond, an aryl group having 6 to 40 carbon atoms (such as C6, C8, C10, C12, C16, C20, C24, C28, C30, C32, C36, or C40, etc.), and a heteroaryl group having 6 to 20 carbon atoms (such as C6, C8, C10, C12, C16, or C20, etc.);

[0079] Ar 41 and Ar 42 are each independently selected from an aryl group having 6 to 40 carbon atoms (such as C6, C8, C10, C12, C16, C20, C24, C28, C30, C32, C36, or C40, etc.) and a heteroaryl group having 6 to 20 carbon atoms (such as C6, C8, C10, C12, C16, or C20, etc.);

[0080] X is selected from CR 41 R 42 or NR 43 wherein R 41 , 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 C1, C2, C3, C4, C5, or C6), an alkoxy group having 1 to 6 carbon atoms (such as C1, C2, C3, C4, C5, or C6), 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, and an alkyl group having 1 to 6 carbon atoms (such as C1, C2, C3, C4, C5, or C6)), and R 41 and R 42 can be connected into a ring through a single bond.

[0081] Preferably, the compound of formula HT-GH4 is selected from any one of the following compounds:

[0082]

[0083]

[0084]

[0085]

[0086]

[0087] The hole blocking layer (HBL) can confine holes and / or excitons within the light-emitting layer range to improve the current efficiency and lifetime of the device. Compared with the light-emitting layer material closest to the HBL interface, the HBL material has a lower HOMO (larger absolute value) and / or a higher triplet energy.

[0088] 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 are no special restrictions 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, phenanthroline structure, carbazole structure, dibenzofuran structure, dibenzothiophene structure.

[0089] In the present invention, there are no special restrictions on the electron transport layer material, and exemplary ones include but are not limited to the following structures:

[0090]

[0091] 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 multilayer structure. If the cathode material is a multilayer 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.

[0092] 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 multilayer 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, BaF2 、MgO、NaF、CsF、Cs 2 CO 3 etc.) or lithium quinolate (LiQ).

[0093] Compared with the prior art, the present invention has the following beneficial effects:

[0094] The invention designs the structure of the carbazole compound to make it suitable for being used as an electron blocking layer material of an organic electroluminescent device. The organic electroluminescent device prepared thereby has a lower driving voltage, a higher current efficiency and a longer service life. DETAILED DESCRIPTION

[0095] For the convenience of understanding the present invention, the present invention lists the following embodiments. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0096] Preparation Example 1

[0097] This preparation example provides an intermediate P1-2 and a synthesis method thereof, and the synthesis method is as follows:

[0098]

[0099] Under nitrogen protection, dry toluene (50 mL), 3-bromophenyltriphenylsilane (4.1 g), carbazole (1.7 g), Pd(dba) were added to a three-necked flask. 2 (bis(dibenzylideneacetonepalladium, 0.0575g), 10% tri-tert-butylphosphine toluene solution (the mass of tri-tert-butylphosphine solution is 0.4g) and sodium tert-butoxide (1.44g), heat to reflux reaction for 6h, cool to room temperature, add water to separate, then wash the organic layer with water until neutral, dry with magnesium sulfate, filter to remove magnesium sulfate, concentrate to dryness, and crystallize with a mixed solvent of methanol and chloroform to obtain intermediate P1-2 (3.6g).

[0100] The intermediate P1-2 was subjected to mass spectrometry detection: the mass-to-charge ratio (m / z) was measured to be 501.19.

[0101] Intermediate Preparation Example 2-6

[0102] Intermediate Preparation Examples 2-6 respectively provide an intermediate and a synthesis method thereof. The synthesis method of the corresponding intermediate refers to the synthesis method of the intermediate P1-2 provided in Preparation Example 1, with the only difference being that different raw materials (see Table 1 below for details) are used for synthesis. The specific structures of raw materials 1 and 2 and the synthesized intermediates are shown in Table 1 below. The intermediates are subjected to mass spectrometry detection, and their mass-to-charge ratio data are also shown in Table 1 below.

[0103] Table 1

[0104]

[0105] Preparation Example 7

[0106] This preparation example provides intermediate P1-1 and its synthesis method, and the synthesis method is as follows:

[0107]

[0108] Under nitrogen protection, add intermediate P1-2 (5.0 g) and DMF (60 mL) to a three-necked flask, and add solid NBS (N-bromosuccinimide, 1.9 g) in batches at 20-25 °C. After the addition, stir and react at 20-25 °C for 6 hours, add water, filter the obtained solid, dry it, and crystallize it with a mixed solvent of methanol and chlorobenzene to obtain intermediate P1-1 (4.6 g).

[0109] Perform mass spectrometry detection on intermediate P1-1: The measured mass-to-charge ratio (m / z) is 579.10.

[0110] Preparation Examples 8-12

[0111] Preparation Examples 8-12 respectively provide an intermediate and its synthesis method. The synthesis method of the corresponding intermediate refers to the synthesis method of intermediate P1-1 provided in Preparation Example 7, except that different raw materials 3 (see Table 2 below) are used to react with NBS to obtain the corresponding intermediate. The specific structure of raw material 3 and the obtained intermediate are shown in Table 2 below, and mass spectrometry detection is performed on the intermediate, and the mass-to-charge ratio data are also shown in Table 2 below.

[0112] Table 2

[0113]

[0114]

[0115] Among them, nuclear magnetic resonance detection is performed on intermediate P6-1, and the data are as follows: 1 H-NMR (Bruker, Switzerland, AvanceⅡ 400 MHz nuclear magnetic resonance spectrometer, CDCl 3 ), δ8.31 (s, 1H), δ8.20 (s, 1H), δ8.05 (d, 1H), δ7.81~7.77 (m, 5H), δ7.50~7.38 (m, 10H), δ7.32~7.06 (m, 16H).

[0116] Synthesis Example 1

[0117] This synthesis example provides compound P1 and its synthesis method, and the synthesis method is as follows:

[0118]

[0119] Under nitrogen protection, add intermediate P1-1 (0.01 mol) and tetrahydrofuran (110 mL) into a three-necked flask, then cool down to -78 °C, slowly add a n-hexane solution containing 0.011 mol of butyllithium (concentration 1.6 M, 6.9 mL), and then keep it at -78 °C to -60 °C for 30 min. Add a solution prepared from 0.011 mol of triphenylchlorosilane and 20 mL of tetrahydrofuran, 0.0001 mol of Pd(dba) 2 、0.0001 mol of anhydrous nickel chloride, slowly warm up to room temperature and react for 2 hours, then warm up to the reflux temperature and react for 2 hours. Cool down, add water and toluene for liquid separation, wash the organic layer until neutral, dry it with anhydrous magnesium sulfate, filter off the desiccant, concentrate to dryness, separate by silica gel column chromatography, and elute with petroleum ether:ethyl acetate = 20:1 (volume ratio) to obtain compound P1 (6.1 g).

[0120] Perform mass spectrometry detection on the obtained compound P1, and the measured mass-to-charge ratio (m / z) is 759.28.

[0121] Synthesis Example 2-6

[0122] Synthesis Example 2-6 respectively provides a compound and its synthesis method. The synthesis method of the corresponding compound refers to the synthesis method of compound P1 provided in Synthesis Example 1. The difference is only that intermediate P1-1 is replaced with other corresponding bromides. Perform mass spectrometry detection on the obtained compound. The specific structures of the bromides, the structures of the synthesized compounds, and their mass-to-charge ratio data are shown in Table 3 below.

[0123] Table 3

[0124]

[0125]

[0126] Synthesis Example 7

[0127] This synthesis example provides compound P5 and its synthesis method. The synthesis method is as follows:

[0128]

[0129] The synthesis method refers to the synthesis method of intermediate P1-2 provided in Preparation Example 1 to prepare compound P5. Perform mass spectrometry detection on the obtained compound P5, and the measured mass-to-charge ratio (m / z) is 1000.37.

[0130] Synthesis Example 8

[0131] This synthesis example provides compound P8 and its synthesis method. The synthesis method is as follows:

[0132]

[0133] The synthesis method refers to the synthesis method of intermediate P1-2 provided in Preparation Example 1 to prepare compound P8. The obtained compound P8 was subjected to mass spectrometry, and the measured mass-to-charge ratio (m / z) was 835.31.

[0134] For compounds not listed above, they can be synthesized with reference to the above methods and combined with common general knowledge in the art. The specific structures of some compounds used in the following Application Examples and Comparative Application Examples are as follows

[0135]

[0136] Application Example 1

[0137] This application example provides a blue organic electroluminescent device using compound P1 provided by the present invention as an electron blocking layer material. The structure of the blue organic electroluminescent device is as follows:

[0138] ITO / HT-1: HI-2[5%](80nm) / HT-1(30nm) / P1(20nm) / H1: PBD-1[5%](35nm) / ETL-1(25nm) / LiF(0.5nm) / Al(150nm).

[0139] The preparation method of the blue organic electroluminescent device is as follows:

[0140] Place the materials in a vacuum chamber and 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.

[0141] 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. In this application example, the host material is H1; 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, and the compound P1 of the present invention forms an electron blocking layer.

[0142] Comparative Application Example 1-2

[0143] Comparative Application Examples 1-2 each provide an organic electroluminescent device, which is only different from Application Example 1 in that the electron blocking layer material compound P1 is replaced with other compounds (see Table 4 below), and other preparation steps and conditions are the same as those in Application Example 1.

[0144] Performance Test

[0145] Test the luminance, driving voltage, current efficiency, and LT95 of the organic electroluminescent devices provided in the above application examples or comparative application examples. Among them, the current efficiency is the corresponding value when the luminance is 1000 cd / m 2 The LT95 refers to the time required for the device efficiency to drop to 95% of the efficiency corresponding to the initial current density while keeping the initial current density of the device at 10 mA / cm 2 unchanged. The driving voltage, current efficiency, and LT95 are relative values. The specific test results are shown in Table 4 below:

[0146] Table 4

[0147] Electron blocking layer material <![CDATA[Luminance / (cd / m 2 )]]> Driving voltage Current efficiency LT95 Application Example 1 P1 1000 0.92 1.03 1.09 Comparative Application Example 1 D1 1000 1 1 1 Comparative Application Example 2 D2 1000 1.03 0.97 0.91

[0148] As can be seen from the above, by designing the structure of the carbazole-based compound, the present invention makes it suitable as an electron blocking layer material for organic electroluminescent devices. The organic electroluminescent device prepared thereby has a lower driving voltage, a higher current efficiency, and a longer service life.

[0149] Application Examples 2-5, Comparative Application Example 3

[0150] Application Examples 2-5 and Comparative Application Example 3 respectively provide a blue-light organic electroluminescent device. The difference from Application Example 1 is only that the electron blocking layer material compound P1 is replaced with other compounds (see Table 5 below), and other preparation steps and conditions are the same as those in Application Example 1.

[0151] Test the luminance, driving voltage, current efficiency, and LT95 of the organic electroluminescent devices provided in the above application examples or comparative application examples. Among them, the current efficiency is the corresponding value when the luminance is 1000 cd / m 2 The LT95 refers to the time required for the device efficiency to drop to 95% of the efficiency corresponding to the initial current density while keeping the initial current density of the device at 10 mA / cm 2 unchanged. The driving voltage, current efficiency, and LT95 are relative values. The specific test results are shown in Table 5 below:

[0152] Table 5

[0153] Electron blocking layer material <![CDATA[Luminance / (cd / m 2 )]]> Driving voltage Current efficiency LT95 Application Example 2 P2 1000 0.91 1.06 1.11 Application Example 3 P3 1000 0.92 1.01 1.23 Application Example 4 P4 1000 0.78 1.00 1.03 Application Example 5 P6 1000 0.98 1.14 1.01 Comparative Application Example 3 D3 1000 1 1 1

[0154] As can be seen from the above, by designing the structure of the carbazole-based compound, the present invention makes it suitable as an electron blocking layer material for organic electroluminescent devices. The organic electroluminescent device prepared thereby has a lower driving voltage, a higher current efficiency, and a longer service life.

[0155] Application Example 6, Comparative Application Examples 4-7

[0156] Application Example 6. Comparative Application Examples 4 - 7 each provide a blue organic electroluminescent device, which is different from Application Example 1 only in that the electron blocking layer material compound P1 is replaced with other compounds (see Table 6 below), and other preparation steps and conditions are the same as those in Application Example 1.

[0157] Test the luminance, driving voltage, current efficiency, and LT95 of the organic electroluminescent devices provided in the above application examples or comparative application examples. 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 6 below:

[0158] Table 6

[0159] Electron blocking layer material <![CDATA[Brightness / (cd / m 2 )]]> Driving voltage Current efficiency LT95 Application Example 6 P5 1000 0.90 1.06 1.09 Comparative Application Example 4 D4 1000 1 1 1 Comparative Application Example 5 D5 1000 1.02 1.04 0.96 Comparative Application Example 6 D6 1000 0.95 1.02 0.99 Comparative Application Example 7 D7 1000 1.09 0.92 1.04

[0160] As can be seen from the above, by designing the structure of the carbazole - based compound, the present invention makes it suitable as the electron blocking layer material of the organic electroluminescent device. The organic electroluminescent device prepared thereby has a lower driving voltage, a higher current efficiency, and a longer service life.

[0161] Application Examples 7 - 8

[0162] Application Examples 7 - 8 each provide a blue organic electroluminescent device, which is different from Application Example 1 only in that the electron blocking layer material compound P1 is replaced with other compounds (see Table 7 below), and other preparation steps and conditions are the same as those in Application Example 1.

[0163] Test the luminance, driving voltage, current efficiency, and LT95 of the organic electroluminescent devices provided in the above application examples or comparative application examples. 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 7 below:

[0164] Table 7

[0165] Electron blocking layer material <![CDATA[Luminance / (cd / m 2 )]]> Driving voltage Current efficiency LT95 Application Example 7 P7 1000 1 1 1 Application Example 8 P8 1000 0.94 1.09 1.01

[0166] As can be seen from the above, by designing the structure of the carbazole compound, the present invention is applicable as an electron blocking layer material for an organic electroluminescent device. The organic electroluminescent device prepared therefrom has a lower driving voltage, a higher current efficiency, and a longer service life.

[0167] The applicant declares that the present invention uses the above embodiments to illustrate the detailed process flow of the present invention. However, 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 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, Ar is selected from any one of an H atom, a C1-C10 alkyl group, a C1-C10 alkoxy group, a C6-C20 aryl group, and a C5-C20 heteroaryl group; and when Ar is selected from a C5-C20 heteroaryl group, the attachment site of Ar is a carbon atom in the heteroaryl group; The hydrogen atoms in the compound of formula I can each independently be substituted by at least one of a deuterium atom, -F, -CN, a C6-C20 aryl group, and a C5-C20 heteroaryl group; The compound of formula I does not include compound D1 and compound D7:

2. The carbazole compound according to claim 1, characterized in that The C1-C10 alkyl group is selected from any one of methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl or decyl, and is more preferably any one of methyl, isopropyl, tert-butyl, methylcyclopentyl, methylcyclohexyl, adamantyl, bicyclo[2.2.1]heptyl or bicyclo[2.2.2]octyl; Preferably, the C1-C10 alkoxy group is selected from any one of methoxy, ethoxy, propoxy, butoxy, and cyclohexyloxy; Preferably, the C6-C20 aryl group is selected from any one of phenyl, naphthyl, biphenyl and 9,9-dimethylfluorenyl; Preferably, the C5-C20 heteroaryl group is selected from any one of dibenzofuranyl, dibenzothiophenyl, carbazolyl and pyridyl.

3. The carbazole compound according to claim 1 or 2, characterized in that Ar is selected from any one of a hydrogen atom, 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, a naphthyl group, a biphenyl group, a 9,9-dimethylfluorenyl group, a carbazolyl group, a dibenzofuranyl group or a dibenzothiophenyl group; Preferably, Ar is selected from any one of a hydrogen atom, a methyl group, a tert-butyl group, a methoxy group, a propoxy group, a phenyl group, a naphthyl group, a biphenyl group, a 9,9-dimethylfluorenyl group, a carbazolyl group, a dibenzofuranyl group or a dibenzothiophenyl group.

4. The carbazole compound according to any one of claims 1 to 3, characterized in that The hydrogen atoms in the compound of formula I can be independently replaced by any one of deuterium atoms, -F, -CN, phenyl, naphthyl, biphenyl, 9,9-dimethylfluorenyl, carbazolyl, dibenzofuranyl or dibenzothiophenyl.

5. The carbazole compound according to any one of claims 1 to 4, characterized in that The carbazole compound has any one of the structures shown in the following formula I-1 to formula I-4: Wherein, Ar has the same definition as in claim 1; The hydrogen atoms in the compounds of formula I-1 to formula I-4 may each independently be substituted by at least one of a deuterium atom, -F, -CN, a C6-C20 aryl group, and a C5-C20 heteroaryl 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 compounds having a structure shown in the following formula MH and compounds having a structure shown in the following formula MXF: Wherein, Ar has the same definition as in claim 1; X2 is selected from any one of -F, -Cl, -Br, -I; The hydrogen atoms in the compound of formula MH and the compound of formula MXF can each independently be substituted by at least one of a deuterium atom, -F, -CN, a C6-C20 aryl group, and a C5-C20 heteroaryl group; The intermediates do not include the following compounds: 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 organic thin film layer comprises the carbazole compound according to any one of claims 1 to 6; Preferably, the organic thin film layer comprises a hole layer, and the hole layer comprises a hole injection layer, a hole transport layer and an electron blocking layer.

10. The organic electroluminescent device according to claim 9, characterized in that: The organic thin film layer comprises an electron blocking layer and a light-emitting layer, and the material of the electron blocking layer comprises the carbazole compound according to any one of claims 1 to 6.

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