A carbazole compound and an organic electroluminescent device

Abstract

This invention provides a carbazole compound and an organic electroluminescent device. The carbazole compound has the structure shown in Formula I. Through the design of the carbazole compound, this invention prepares a carbazole compound with excellent performance. The organic electroluminescent device prepared by using the carbazole compound as the material of the light-emitting layer has high current efficiency and long lifespan.

Description

Technical Field

[0001] This invention belongs to the field of organic electroluminescent materials technology, specifically relating to a carbazole compound and an organic electroluminescent device. Background Technology

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

[0003] The structure of an organic light-emitting diode (OLED) consists of an anode, a cathode, and an organic layer between them. To improve the efficiency and stability of OLEDs, the organic material layer comprises multiple layers of different materials. To meet the increasingly demanding requirements of OLED devices, there is an urgent need to develop a wider variety of materials to improve the performance of OLED devices in terms of current efficiency, lifetime, and other aspects. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a carbazole-based compound and an organic electroluminescent device. Through the design of carbazole-based compounds, the present invention prepares high-performance carbazole-based compounds. Organic electroluminescent devices prepared using these carbazole-based compounds as the light-emitting layer material exhibit high current efficiency and long lifespan.

[0005] To achieve this objective, the present invention adopts the following technical solution:

[0006] On one hand, the present invention provides a carbazole compound having the structure shown in Formula I:

[0007]

[0008] Among them, Ar1 and Ar2, one is selected from H, and the other is selected from any one or a combination of at least two of phenyl, naphthyl, biphenyl, triphenylene, fluoranyl, 9,9-dimethylfluorenyl, carbazolyl, N-phenyl-substituted carbazolyl, N-biphenyl-substituted carbazolyl, dibenzofuranyl or dibenzothiophene.

[0009] Ar3, Ar4, Ar5, and Ar6 are independently selected from any one or a combination of at least two of H, phenyl, naphthyl, biphenyl, triphenylene, fluoranyl, 9,9-dimethylfluorenyl, carbazolyl, N-phenyl-substituted carbazolyl, N-biphenyl-substituted carbazolyl, dibenzofuranyl, or dibenzothiophene.

[0010] In compound I, the hydrogen atoms can be independently replaced by deuterium (D), -F, -CN, C1-C12 alkyl, C1-C12 alkoxy, or triphenylsilyl (D). Dashed lines indicate connection sites (the same applies below), triphenylmethyl At least one of the following substitutions is selected from C6-C20 aryl or C6-C20 heteroaryl:

[0011] In the carbazole compounds of this invention, as shown in Formula I, there are two carbazole groups at the ortho-substituted position on the benzene ring, placing these two carbazole groups in a relatively parallel position. Since the carbazole groups are electron-donating groups, the structure of the two ortho-substituted carbazole groups on the benzene ring and the benzene ring between them has a large electron cloud density distribution, making it more suitable for charge transfer. Furthermore, the selection of aryl or heteroaryl groups at Ar1 or Ar2 further gives the material suitable HOMO and LUMO energy levels and good film-forming properties. Therefore, organic electroluminescent devices prepared using carbazole compounds as the light-emitting layer material exhibit low voltage, high current efficiency, and long lifetime.

[0012] In this invention, C1-C12 can be C1, C2, C3, C4, C5, C6, C7, C8, C9 or C12. C6-C20 can be C6, C10, C12, C15, C18 or C20, etc.

[0013] In this invention, "D" represents a deuterium atom, and the same applies below.

[0014] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. The purpose and beneficial effects of the present invention can be better achieved and realized through the following preferred technical solutions.

[0015] As a preferred embodiment 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.

[0016] Preferably, the C1-C12 alkoxy group is selected from any one of methoxy, ethoxy, propoxy, butoxy, pentoxy, or hexoxy.

[0017] Preferably, the C6-C20 aryl group is selected from any one of phenyl, naphthyl, biphenyl, or 9,9-dimethylfluorenyl.

[0018] Preferably, the C6-C20 heteroaryl group is selected from any one of carbazolyl, dibenzofuranyl, or dibenzothiophenel.

[0019] As a preferred embodiment of the present invention, each hydrogen atom in the compound of Formula I can be independently replaced by at least one of the following: deuterium atom (D)-F, -CN, methoxy, tert-butyl, phenyl, biphenyl, naphthyl, dibenzofuranyl, carbazoleyl, and triphenylsilyl.

[0020] As a preferred embodiment of the present invention, the carbazole compound is selected from any one of the following substituted or unsubstituted compounds:

[0021]

[0022]

[0023]

[0024] The substitution refers to the independent replacement of each hydrogen atom in the carbazole compound by a deuterium atom. Preferably, the carbazole compound is selected from any one of the following compounds:

[0025]

[0026] In this invention, there are no special restrictions on the preparation method of carbazole compounds, and commonly used preparation methods in the art are applicable.

[0027] In a second aspect, the present invention provides an intermediate for preparing a carbazole compound as described in any one of claims 1-5, said intermediate having the structure shown in formula MA:

[0028]

[0029] Ar3, Ar4, Ar5, and Ar6 are defined as in Equation I;

[0030] X1 is selected from any one of F, Cl, Br or I;

[0031] In MA, each hydrogen atom can be independently replaced by a deuterium atom (D), -F, -CN, C1-C12 alkyl, C1-C12 alkoxy, or triphenylsilyl. Triphenylmethyl At least one of the following substitutions: C6-C20 aryl or C6-C20 heteroaryl;

[0032] The intermediate does not include:

[0033]

[0034] The intermediate is used to prepare carbazole compounds as described in the first aspect.

[0035] Preferably, the intermediate comprises the following compounds:

[0036]

[0037] In this invention, the synthetic route for the intermediates described above is provided as follows:

[0038]

[0039] In this invention, the intermediate MA is used to synthesize the carbazole compounds described herein, and the synthetic route is as follows:

[0040]

[0041] Ar1, Ar2, Ar3, Ar4, Ar5, and Ar6 are as defined above;

[0042] X1 and X2 are independently selected from F, Cl, Br, and I;

[0043] The hydrogen atoms in MA and Formula I can each be independently replaced by deuterium (D), -F, -CN, C1-C12 alkyl, C1-C12 alkoxy, or triphenylsilyl. Triphenylmethyl At least one of the following substitutions is selected from C6-C20 aryl or C6-C20 heteroaryl:

[0044] Thirdly, the present invention provides an organic electroluminescent device, the organic electroluminescent device comprising 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 carbazole compounds as described in the first aspect.

[0046] Preferably, the organic thin film layer includes a light-emitting layer, and the main material of the light-emitting layer includes carbazole compounds as described in the first aspect.

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

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

[0049] As a preferred embodiment of the present invention, the organic electroluminescent device is a green organic electroluminescent device.

[0050] In this invention, the light-emitting layer comprises a host material and a dopant material, wherein the dopant material is also called a dye or a phosphorescent material. The host material of the light-emitting layer can be a single compound or a mixture of two or more carbazole compounds as described in the first aspect.

[0051] The light-emitting layer includes a phosphorescent light-emitting layer, which 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.

[0052] The volume percentage of the main material in the phosphorescent luminescent layer is 60% to 99.9% (e.g., it can be 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, or 99.9%), preferably 70% to 99.5%, and more preferably 85% to 95%.

[0053] In this invention, the doping material of the light-emitting layer can be a phosphorescent material, also known as a triplet luminescent material, which refers to the light emitted by a substance from a triplet excited state. The specific selection of phosphorescent materials in this invention is not particularly limited; commonly used doping materials for the light-emitting layer in this field are applicable, including but not limited to: compounds having a structure as shown in formula PD.

[0054]

[0055] Wherein, M is selected from any one of Ir, Pt, Pd, Os, Ti, Zr, Hf, Eu, Tb, Tm, Cu or Au;

[0056] Y1-Y4 are each independently selected from carbon or nitrogen;

[0057] Y1 and Y2 can be connected by a single key or a double key, and Y3 and Y4 can be connected by a single key or a double key.

[0058] Cy1 and Cy2 are each independently selected from any one of phenyl, naphthyl, fluorenyl, spirofluorenyl, indyl, pyrroleyl, thiopheneyl, furanyl, imidazolyl, pyrazolyl, thiazolyl, isothiazolyl, pyridinyl, pyrazinyl, pyrimidinyl, pyridazinyl, quinolinyl, isoquinolinyl, benzoquinolinyl, quinoxalinyl, quinazolinyl, carbazoleyl, benzimidazolyl, benzofuranyl, benzothiopheneyl, isobenzothiopheneyl, benzimidazolyl, benzozolyl, triazolyl, tetrazolyl, diazolyl, triazinyl, dibenzofuranyl, dibenzothiopheneyl, N-hexacarbazolyl, N-hexadibenzofuranyl, wherein Cy1 and Cy2 may optionally be linked to each other via a single bond or an organic linking group;

[0059] Any two or more ligands of M can be connected by single or double bonds, or by O or S bridging, or by any chemical group or chemical structure to form a structure that conforms to chemical principles.

[0060] R 91 and R 92 Each group is independently selected from -H, -D, -F, -Cl, -Br, -I, hydroxyl, cyano, nitro, amino, amidine, hydrazine, hydrazone, carboxylic acid group, carboxylate group, sulfonic acid group, sulfonate group, phosphate group, phosphate group, -SF5, substituted or unsubstituted C1-C60 (e.g., can be C1, C5, C10, C15, C20, C25, C30, C35, C40, C45, C50, C55, or C60, etc.) alkyl, substituted or unsubstituted C2-C6. 0 (e.g., can be C2, C5, C10, C15, C20, C25, C30, C35, C40, C45, C50, C55, or C60, etc.) alkenyl, substituted or unsubstituted C2-C60 (e.g., can be C2, C5, C10, C15, C20, C25, C30, C35, C40, C45, C50, C55, or C60, etc.) alkynyl, substituted or unsubstituted C1-C60 (e.g., can be C1, C5, C10, C15, C20, C40, C50, C55, C60, etc.) alkyne, substituted or unsubstituted C1-C60 (e.g., can be C1, C5, C10, C15, C20, C50, C10, C15, C20, C1 ... 25. alkoxy, substituted or unsubstituted C2-C10 (e.g., C2, C3, C4, C5, C6, C7, C8, C9, or C10), heterocyclic alkyl, substituted or unsubstituted C6-C60 (e.g., C6, C12, C15, C18, C24, C30, C32, C36, C40, C42, C54, or C60), aryl, substituted or unsubstituted C6-C60 (… For example, it can be any one of the following: aryloxy group (C6, C12, C15, C18, C24, C30, C32, C36, C40, C42, C54 or C60, etc.), substituted or unsubstituted C6-C60 (e.g., it can be C6, C12, C15, C18, C24, C30, C32, C36, C40, C42, C54 or C60, etc.), substituted or unsubstituted monovalent non-aromatic fused polycyclic group, substituted or unsubstituted monovalent non-aromatic fused heterocyclic group;

[0061] a1 and a2 are each independent integers selected from 1 to 5, for example, they can be 1, 2, 3, 4 or 5;

[0062] b is an integer selected from 0 to 4, for example, it can be 0, 1, 2, 3 or 4;

[0063] a is selected from 1, 2, or 3;

[0064] L1 can be a monovalent organic ligand, a divalent organic ligand, or a trivalent organic ligand.

[0065] Preferably, the PD compound is selected from any one of the following compounds:

[0066]

[0067]

[0068]

[0069]

[0070]

[0071]

[0072]

[0073] The organic thin film layer of the organic electroluminescent device of the present invention further includes at least one of a hole injection layer, a hole transport layer, an electron blocking layer, or an electron transport layer.

[0074] In this invention, the organic thin film layer includes a hole layer, which comprises a hole injection layer, a hole transport layer, and an electron blocking layer.

[0075] The hole injection layer material includes a P-type dopant. The P-type dopant coexists with the hole injection layer material in the OLED device and can oxidize the hole injection layer material, thereby acting as an electron acceptor and promoting the movement of holes from the hole injection layer to the anode. In this invention, the difference between the absolute value of the LUMO of the P-type dopant and the absolute value of the HOMO of the hole layer material is greater than -0.2V, preferably greater than -0.1eV, more preferably greater than 0eV, more preferably greater than 0.1eV, and more preferably greater than 0.2eV.

[0076] The P-type dopant exists in the hole injection layer at a volume percentage of 1% to 10% (e.g., 1%, 2%, 4%, 6%, 8%, or 10%). In this invention, no particular limitation is made on the type of P-type dopant; exemplarily, compounds D-1 to D-13 disclosed in CN113728453A or compounds HI-1 to HI-9 as described below can be used.

[0077]

[0078]

[0079] In this invention, the hole layer material (including a hole injection layer, a hole transport layer, and an electron blocking layer) has the structure shown in the following formula HT-GH4:

[0080]

[0081] Among them, L 41 Selected from single-bonded, C6-C40 (e.g., C6, C8, C10, C12, C16, C20, C24, C28, C30, C32, C36, or C40, etc.) aryl, and C6-C20 (e.g., C6, C8, C10, C12, C16, or C20, etc.) heteroaryl;

[0082] Ar 41 Ar 42 Each is independently selected from C6-C40 (e.g., C6, C8, C10, C12, C16, C20, C24, C28, C30, C32, C36, or C40, etc.) aryl and C6-C20 (e.g., C6, C8, C10, C12, C16, or C20, etc.) heteroaryl;

[0083] X is selected from CR 41 R 42 Or NR 43 , where R 41 R 42 R 43 Each is independently selected from any one of substituted or unsubstituted phenyl groups (the substituents are selected from C1-C6 (e.g., C1, C2, C3, C4, C5, or C6) alkyl, C1-C6 (e.g., C1, C2, C3, C4, C5, or C6) alkoxy, dibenzofuranyl, naphthyl, triphenylene, fluoranyl, 9,9-dimethylfluorenyl, biphenyl, substituted or unsubstituted dibenzofuranyl (the substituent is phenyl), substituted or unsubstituted dibenzothiophenyl (the substituent is phenyl), dibenzofuran-substituted thiophenyl, C1-C6 (e.g., C1, C2, C3, C4, C5, or C6) alkyl, R 41 R 42 They can be connected into a ring using a single key.

[0084] In this invention, the hole layer material (including a hole injection layer, a hole transport layer, and an electron blocking layer) further includes a compound having a structure as shown in Formula IA or a compound having a structure as shown in Formula IB:

[0085]

[0086] Wherein, L is selected from any one of C6-C40 (e.g., it can be C6, C8, C10, C12, C16, C20, C24, C28, C30, C32, C36 or C40, etc.) arylene, dibenzofuranyl or dibenzothiophene group;

[0087] m is selected from an integer between 0 and 4 (for example, it can be 0, 1, 2, 3 or 4), and n is selected from 0 or 1;

[0088] Ar is selected from any one of triphenylene, fluorene anthracene, dibenzofuranyl or dibenzothiophene;

[0089] Ar1 and Ar2 are each independently selected from any one of aryl, dibenzofuranyl, or dibenzothiophene groups containing C6-C40 (e.g., C6, C8, C10, C12, C16, C20, C24, C28, C30, C32, C36, or C40, etc.);

[0090] Ar1 and Ar, Ar2 and Ar, and Ar1 and Ar2 can be independently connected or bridged by single bonds, O, S, CR1R2, NR.

[0091] R, R1, and R2 are each independently selected from any one of the following: C1-C20 (e.g., C1, C2, C4, C6, C8, C10, C12, C14, C16, C18, or C20), alkyl, C6-C40 (e.g., C6, C8, C10, C12, C16, C20, C24, C28, C30, C32, C36, or C40), aryl, dibenzofuranyl, or dibenzothiopheneyl.

[0092] In compounds of formula IB and formula IA, the hydrogen atoms can be independently replaced by at least one of -F, -CN, -D (deuterium atom), C1-C6 alkyl, C1-C6 alkoxy, phenyl, biphenyl, naphthyl, phenanthryl, anthracene, fluorenyl, benzo[a]fluorenyl, dibenzo[a]fluorenyl, triphenylene, fluoranyl, pyrene, perylene, spirofluorenyl, indo[a]fluorenyl, or hydrogenated benzo[a]anthryl.

[0093] Preferably, the Ar is fluoreneanthracene, where m+n>1.

[0094] Preferably, the H in the compounds of formula IB and formula IA can be replaced by at least one of -F, -CN, -D, C1-C3 alkyl (e.g., methyl, ethyl, or propyl), C1-C3 alkoxy (e.g., methoxy, ethoxy, or propoxy), phenyl, biphenyl, triphenylene, and fluoranthyl.

[0095] Preferably, L, Ar1, and Ar2 are each independently selected from at least one of phenyl, biphenyl, naphthyl, phenanthryl, anthracene, fluorenyl, benzo[a]fluorenyl, dibenzo[a]fluorenyl, triphenylene, fluoranyl, pyrene, perylene, spirofluorenyl, indo[a]fluorenyl, or hydrogenated benzo[a]anthryl.

[0096] Preferably, the compound of formula IB is selected from any one of the following compounds:

[0097]

[0098]

[0099] In the OLED device provided by this invention, the hole layer material, in addition to the compounds described in formula HT-GH4, formula IB, and formula IA, may also include conventional hole materials in the art, without particular limitation. Exemplarily, it includes, but is not limited to, triarylamine compounds or carbazole compounds. Preferably, triarylamine compounds or carbazole compounds containing three or more nitrogen atoms are preferred because they have a higher HOMO (lower absolute value) and are more suitable as hole injection layer materials. Triarylamine compounds or carbazole compounds containing two or one nitrogen atom can be used as hole transport layer materials. Some compounds or carbazole compounds containing one nitrogen atom, if they have a high LUMO, can also be used as electron blocking layer materials.

[0100] The triarylamine compound or carbazole compound is used as the hole layer material, and the hole layer material includes compounds having any of the following structures:

[0101]

[0102] Among them, Ar 601 ~Ar 609 Each is independently selected from any one of the following: substituted or unsubstituted C6-C40 (e.g., C6, C8, C10, C12, C16, C20, C24, C28, C30, C32, C36, or C40, etc.) aryl, substituted or unsubstituted dibenzofuranyl, substituted or unsubstituted dibenzothiophene, substituted or unsubstituted naphthobenzofuranyl, substituted or unsubstituted naphthobenzothiophene, substituted or unsubstituted dinaphthofuranyl, substituted or unsubstituted dinaphthothiophene.

[0103] And Ar 601 ~Ar 609 Ar atoms that are adjacent to or connected to the same N atom 601 ~Ar 609 It can be connected via a single key or via O, S, CR 701 R702 NR 703 bridging;

[0104] R 701 R 702 R 703 Selected from C6-C40 (e.g., C6, C8, C10, C12, C16, C20, C24, C28, C30, C32, C36, or C40, etc.) aryl, C6-C20 (e.g., C6, C8, C10, C12, C16, or C20, etc.) heteroaryl, C1-C6 (e.g., C1, C2, C3, C4, C5, or C6) alkyl, and R 701 R 702 It can be connected with a single button.

[0105] Hole blocking layers (HBLs) can confine holes and / or excitons within the emissive layer to improve device current efficiency and lifetime. Compared to emissive layer materials closest to the HBL interface, HBL materials exhibit lower HOMO (larger absolute values) and / or higher triplet energies.

[0106] An electron transport layer (ETL) may comprise a material capable of transporting electrons. The ETL may be intrinsic (undoped) or doped, and doping can be used to enhance conductivity. In this invention, there are no particular limitations on the ETL material; any metal complex or organic compound can be used, as long as it can transport electrons. Generally, electron transport layer materials contain at least one of the following structural segments: pyridine, pyrimidine, triazine, benzimidazole, benzoxazole, benzothiazole, N-naphthalene, N-phenanthion, N-carbazole, N-dibenzofuran, and N-dibenzothiophene.

[0107] In this invention, no special restrictions are placed on the electron transport layer material, which includes, but is not limited to, the following:

[0108]

[0109]

[0110]

[0111]

[0112]

[0113]

[0114]

[0115] In this invention, the cathode material is a metal with low work function (e.g., alkaline earth metals, alkali metals, main group metals, or lanthanides (e.g., Ca, Ba, Mg, Al, In, Mg, Yb, Sm, etc.)), a metal alloy composed of multiple metals (an alloy composed of alkali metals or alkaline earth metals 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 relatively high work function can also be used, such as Ag or Al. In this case, combinations of the metals are typically used, such as Ca / Ag, Mg / Ag, or Ba / Ag.

[0116] Alternatively, a thin interlayer of material with a high dielectric constant can be introduced 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 can be an alkali metal or alkaline earth metal fluoride, as well as the corresponding oxide or carbonate (e.g., LiF, Li2O, BaF2, MgO, NaF, CsF, Cs2CO3, etc.) or lithium quinoline (LiQ).

[0117] Compared with the prior art, the present invention has the following beneficial effects:

[0118] In this invention, the structure of carbazole compounds is designed to make them suitable as the main material for the light-emitting layer of organic electroluminescent devices, thereby enabling the organic electroluminescent devices to have high current efficiency and long lifespan. Detailed Implementation

[0119] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0120] Preparation Example 1

[0121] This preparation example provides intermediate P1-1 and its synthesis method, which is as follows:

[0122]

[0123] Under a nitrogen atmosphere, dry toluene (60 mL), intermediate P1-0 (3.3 g), o-dibromobenzene (2.3 g), Pd(dba)2 (bis(dibenzylacetone)palladium, 0.1 g), 8 g of 10% tri-tert-butylphosphine toluene solution (the mass of the tri-tert-butylphosphine solution was 0.8 g), and sodium tert-butoxide (1.2 g) were added to a three-necked flask. The mixture was heated to reflux temperature and reacted for 4 h. After cooling to room temperature, water was added to dissolve the mixture. The organic layer was then washed with water until neutral, dried with magnesium sulfate, filtered to remove magnesium sulfate, concentrated to dryness, and separated by silica gel column chromatography. The eluent was petroleum ether:ethyl acetate = 20:1 (volume ratio) to obtain intermediate P1-1 (3.1 g).

[0124] Mass spectrometry analysis of intermediate P1-1 showed a mass-to-charge ratio (m / z) of 486.07.

[0125] Preparation Example 2

[0126] This preparation example provides intermediate P2-1 and its synthesis method, which is as follows:

[0127]

[0128] Following the same synthesis method as intermediate P1-1, but using the same raw materials, intermediate P2-1 was prepared.

[0129] Mass spectrometry analysis of intermediate P2-1 revealed a mass-to-charge ratio (m / z) of 486.07.

[0130] Preparation Example 3

[0131] This preparation example provides intermediate P3-1 and its synthesis method, which is as follows:

[0132]

[0133] Following the same synthesis method as intermediate P1-1, but using the same raw materials, intermediate P3-1 was prepared.

[0134] Mass spectrometry analysis of intermediate P3-1 revealed a mass-to-charge ratio (m / z) of 562.10.

[0135] Synthesis Example 1

[0136] This synthetic example provides compound P1 and its synthetic method, which is as follows:

[0137]

[0138] Under a nitrogen atmosphere, dry toluene (110 mL), intermediate P1-1 (4.9 g), intermediate P1-2 (2.5 g), Pd(dba)2 (bis(dibenzylacetone)palladium, 0.1 g), 8 g of 10% tri-tert-butylphosphine toluene solution (the mass of the tri-tert-butylphosphine solution was 0.8 g), and sodium tert-butoxide (1.2 g) were added to a three-necked flask. The mixture was heated to reflux temperature and reacted for 6 h. After cooling to room temperature, water was added to dissolve the mixture. The organic layer was then washed with water until neutral, dried with magnesium sulfate, filtered to remove magnesium sulfate, concentrated to dryness, and separated by silica gel column chromatography. The elution was performed with petroleum ether:ethyl acetate = 20:1 (volume ratio) to give compound P1 (5.5 g).

[0139] Mass spectrometry analysis of compound P1 showed a mass-to-charge ratio (m / z) of 649.25.

[0140] Synthesis Examples 2-10

[0141] Synthesis Examples 2-10 each provide a compound. The synthesis method of the compound can refer to the synthesis method of compound P1 provided in Synthesis Example 1. The corresponding raw materials are used to react and prepare the corresponding compound, as shown in Table 1 below.

[0142] The obtained compounds were analyzed by mass spectrometry, and the mass-to-charge ratio (m / z) data are shown in Table 1 below.

[0143] Table 1

[0144]

[0145]

[0146] For other compounds whose specific synthetic methods are not listed, synthesis can be performed by referring to the above examples and combining them with common knowledge in the art. The specific structures of some compounds used in the following application examples and comparative application examples are as follows:

[0147]

[0148]

[0149] Synthesis of compound D3:

[0150]

[0151] Following the synthesis method of compound P1 provided in Synthesis Example 1, and using the corresponding starting materials, the corresponding compound D3 was prepared.

[0152] Mass spectrometry analysis of compound D3 revealed a mass-to-charge ratio (m / z) of 649.25.

[0153] Application Example 1

[0154] This application example provides a blue organic electroluminescent device, using 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:

[0155] ITO / HT-1: HI-2[5%](80nm) / HT-1(30nm) / EB-1(20nm) / Main material: PBD-1[5%](35nm) / ETL-1(25nm) / LiF(0.5nm) / Al(150nm).

[0156] The fabrication method of the blue organic electroluminescent device is as follows:

[0157] The material was placed inside a vacuum chamber, and the vacuum was evacuated to 1×10⁻⁶. -5 ~1×10 -6 Pa, the above materials are sequentially vacuum-deposited onto the cleaned ITO substrate to prepare OLED devices.

[0158] 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 material HT-1 and the P-type dopant HI-2 is 95:5, HT-1 is the hole transport material; HT-1:HI-2[5%] is used as the hole injection layer material, and EB-1 is the electron blocking layer material.

[0159] Application Example 2-11

[0160] Application Examples 2-11 provide a blue organic electroluminescent device, which differs from Application Example 1 only in that the host material compound P1 of the light-emitting layer is replaced with other compounds (see Table 1 below). The other preparation steps and conditions are the same as in Application Example 1.

[0161] Comparative Application Examples 1-3

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

[0163] Performance testing

[0164] The luminance, driving voltage, current efficiency, and LT95 of the organic electroluminescent devices provided above were tested. The current efficiency is measured when the luminance is 1000 cd / m². 2 The corresponding value, LT95, refers to maintaining an initial device current density of 10 mA / cm². 2The time required for the device efficiency to drop to 95% of the efficiency corresponding to the initial current density is constant, where voltage, current efficiency, and LT95 are relative values ​​(with Application Example 1 as the reference standard). Specific test results are shown in Table 2 below.

[0165] Table 2

[0166] Application Example 1 P1 PBD-1 1000 1 1 1 Application Example 2 P11 PBD-1 1000 1.02 0.96 1.09 Application Example 3 P12 PBD-1 1000 1.04 0.97 1.11 Application Example 4 P13 PBD-1 1000 0.97 1.02 1.01 Application Example 5 P14 PBD-1 1000 1.93 1.05 0.96 Application Example 6 P15 PBD-1 1000 1.02 1.29 1.02 Application Example 7 P16 PBD-1 1000 1.06 1.08 1.57 Application Example 8 P17 PBD-1 1000 1.05 1.24 1.22 Application Example 9 P18 PBD-1 1000 1.01 0.98 1.17 Application Example 10 P2 PBD-1 1000 0.90 1.02 0.87 Application Example 11 P21 PBD-1 1000 1.02 1.09 0.98 Application Example 12 P3 PBD-1 1000 1.03 0.97 1.15 Comparative Application Example 1 D1 PBD-1 1000 1.13 0.87 0.86 Comparative Application Example 2 D2 PBD-1 1000 1.11 0.76 0.71 Comparative Application Example 3 D3 PBD-1 1000 1.26 0.81 0.80

[0167] A comparison of Application Example 1 and Application Example 10 shows that the change in the leftmost carbazole linkage position of compound P2 used in Application Example 10 resulted in a lower voltage in the organic electroluminescent device prepared using compound P2 in Application Example 10.

[0168] Application Examples 6 and 8 show good efficiency, while Application Example 7 shows good lifetime. It can be seen that when one of Ar1 and Ar2 in Formula I is selected from carbazole group, the device performance is better.

[0169] Comparing Application Example 6 and Application Example 8, and comparing Application Example 1 and Application Example 9, it can be seen that when Ar2 in Equation I is selected from H or D, the device lifetime is improved.

[0170] Comparing Application Example 11 and Application Example 10, when Formula I is replaced by triphenylsilane, the device efficiency and lifetime are improved.

[0171] Comparing Application Example 12 with Application Example 1, when at least one of Ar3, Ar4, Ar5, and Ar6 in Equation I is not selected from H, the device lifetime is improved.

[0172] As can be seen from the above, by designing the structure of carbazole compounds, this invention makes them suitable as the main material for the light-emitting layer of organic electroluminescent devices, thereby enabling the organic electroluminescent devices to have high current efficiency and long lifespan.

[0173] The applicant declares that the above embodiments illustrate the carbazole compounds and organic electroluminescent devices of the present invention, but the present invention is not limited to the above embodiments, that is, it does not mean that the present invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A carbazole compound, characterized in that, The carbazole compound is selected from any one of the following compounds: 、 、 、 、 、 。 2. An organic electroluminescent device, characterized in that, The organic electroluminescent device includes an anode, a cathode, and an organic thin film layer disposed between the anode and the cathode; the organic thin film layer includes a light-emitting layer, and the main material of the light-emitting layer includes a carbazole compound as described in claim 1.

3. The organic electroluminescent device according to claim 2, characterized in that, The light-emitting layer is a phosphorescent light-emitting layer.

4. The organic electroluminescent device according to claim 2, characterized in that, The light-emitting layer also includes doped materials.

5. The organic electroluminescent device according to claim 2, characterized in that, The volume percentage of the main material in the light-emitting layer is 60% to 99.9%.

6. The organic electroluminescent device according to claim 5, characterized in that, The volume percentage of the main material in the light-emitting layer is 70% to 99.5%.

7. The organic electroluminescent device according to claim 6, characterized in that, The volume percentage of the main material in the light-emitting layer is 85% to 95%.

8. The organic electroluminescent device according to claim 2, characterized in that, The organic thin film layer further includes at least one of a hole injection layer, a hole transport layer, an electron blocking layer, or an electron transport layer.

9. The organic electroluminescent device according to claim 2, characterized in that, The organic electroluminescent device is a blue organic electroluminescent device.

10. The organic electroluminescent device according to claim 2, characterized in that, The organic electroluminescent device is a green organic electroluminescent device.

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