A carbazole compound, an organic electroluminescence device comprising the same

Abstract

This invention provides a carbazole compound and an organic electroluminescent device comprising the carbazole compound. The carbazole compound has the structure shown in Formula I or Formula II. By designing the structure of the carbazole compound, this invention makes it suitable as the main material for the light-emitting layer of an organic electroluminescent device, thereby enabling the organic electroluminescent device to have high current efficiency and long lifetime.

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 containing it. Background Technology

[0002] Electroluminescence, also known as electroluminescence or EL for short, is a light-emitting phenomenon in which a solid directly converts electrical energy into light energy by generating an electric field through a voltage applied to two electrodes. Among these, electroluminescence from organic materials is an injection-type composite light emission. Based on their function and structure in organic electroluminescent (OLED) devices, organic electroluminescent materials can be further classified into hole injection layer (HIL), hole transport layer (HTL), emissive layer (EML), electron transport layer (ETL), and electron injection layer (EIL), among others.

[0003] Currently, organic light-emitting diodes (OLEDs) have become the mainstream display technology, and correspondingly, various new OLED materials have been developed. However, their various properties still need improvement, especially in terms of efficiency, lifespan, and voltage. To meet the higher requirements for OLED devices, there is an urgent need in this field to develop more types and higher-performance blue light host materials. 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 containing it. In this invention, the structure of the carbazole-based compound is designed to be suitable as the main material for the light-emitting layer of the organic electroluminescent device, thereby enabling the organic electroluminescent device to exhibit high current efficiency and long lifespan.

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

[0006] In a first aspect, the present invention provides a carbazole compound having a structure as shown in Formula I or a structure as shown in Formula II:

[0007]

[0008] Ar1 and Ar2 are each independently selected from C6-C40 aryl or C6-C30 heteroaryl;

[0009] R1 and R2 are each independently selected from any one of -H, C6-C40 aryl, or C6-C30 heteroaryl, and at least one of R1 and R2 is not selected from -H;

[0010] R3 is selected from C6-C40 aryl or C6-C30 heteroaryl;

[0011] X is selected from C or Si;

[0012] In compounds of formula I and formula II, the hydrogen atoms can be independently substituted by at least one of -D, C6-C20 aryl, C1-C12 alkyl, or C1-C12 alkoxy.

[0013] In this invention, the structure of carbazole compounds is designed, and the structure contains... Groups and In contrast, the two benzene rings in the compound of this invention are connected by single bonds, giving the molecule greater rigidity and reducing energy loss due to molecular vibration. This allows for better energy transfer to the dye (dopant) when used as the host material for the light-emitting layer of an organic electroluminescent device, resulting in higher current efficiency and a longer lifetime for the organic electroluminescent device. Furthermore, the selection of Ar1 increases the overall steric hindrance and raises T1, making it even more suitable as the host material for the light-emitting layer of an organic electroluminescent device.

[0014] In this invention, C6-C40 can be C6, C8, C10, C12, C16, C20, C24, C28, C30, C32, C36 or C40, etc.

[0015] C6-C30 can be C6, C8, C10, C12, C16, C20, C24, C28, or C30, etc.

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

[0017] C1-C12 can be C1, C2, C4, C6, C8, C10, or C12, etc.

[0018] It should be noted that in this invention, "-D" represents a deuterium atom, and the same applies below.

[0019] 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.

[0020] As a preferred embodiment of the present invention, the C6-C40 aryl group is selected from any one of phenyl, biphenyl, terphenyl, naphthyl, naphthylphenyl, anthracene, phenanthrene, fluorenyl, benzo[a]fluorenyl, dibenzo[a]fluorenyl, naphthyl, pyrene, perylene, spirofluorenyl, triphenylene, fluoranyl, hydrogenated benzo[a]anthreneyl, ind[a]fluorenyl, benzo[a]ind[a]fluorenyl, dibenzo[a]ind[a]fluorenyl, naphthyl, or benzo[a]naphthylfluorenyl.

[0021] Preferably, the C6-C30 heteroaryl group is selected from any one of carbazolyl, dibenzofuranyl, dibenzothiophenyl, naphthobenzofuranyl, naphthobenzothiophenyl, dinaphthofuranyl, and dinaphthothiophenyl.

[0022] Preferably, the C6-C20 aryl group is selected from any one of phenyl, biphenyl, terphenyl, naphthyl, anthracene, phenanthrene, fluorene, triphenylene, and fluoranthracene.

[0023] Preferably, the C1-C12 alkyl group is selected from any one of methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl or decyl.

[0024] Preferably, the C1-C12 alkoxy group is selected from any one of methoxy, ethoxy, propoxy, butoxy, pentoxy, or hexoxy.

[0025] In the preferred embodiment of the present invention, Ar1 and Ar2 are each independently selected from any one of phenyl, carbazolyl, diphenyl, fluorenyl, naphthyl, triphenylene, fluoranyl, indofluorenyl, dibenzofuranyl, dibenzothiophene, naphthobenzofuranyl or naphthobenzothiophene.

[0026] Preferably, Ar1 and Ar2 are each independently selected from any one of phenyl, naphthyl, diphenyl, triphenylene, 9,9-dimethylfluorenyl, carbazolyl, dibenzofuranyl, and dibenzothiophene.

[0027] Preferably, the Ar1 is selected from any one of phenyl, naphthyl, or diphenyl.

[0028] Preferably, the Ar2 is selected from any one of phenyl, naphthyl, diphenyl, triphenylene, 9,9-dimethylfluorenyl, carbazole, dibenzofuranyl, and dibenzothiopheneyl.

[0029] In the preferred embodiment of the present invention, R1 and R2 are each independently selected from any one of -H, phenyl, carbazolyl, diphenyl, fluorenyl, naphthyl, triphenylene, fluoranyl, indofluorenyl, dibenzofuranyl, dibenzothiophene, naphthobenzofuranyl or naphthobenzothiophene, and at least one of R1 and R2 is not selected from -H.

[0030] Preferably, R1 and R2 are each independently selected from any one of -H, phenyl, naphthyl, diphenyl, 9,9-dimethylfluorenyl, carbazolyl, dibenzofuranyl, and dibenzothiophene, and at least one of R1 and R2 is not selected from -H.

[0031] As a preferred embodiment of the present invention, R3 is selected from any one of phenyl, carbazolyl, diphenyl, fluorenyl, naphthyl, triphenylene, fluoranyl, indofluorenyl, dibenzofuranyl, dibenzothiophene, naphthobenzofuranyl, or naphthobenzothiophene.

[0032] Preferably, R3 is selected from any one of phenyl, naphthyl, diphenyl, 9,9-dimethylfluorenyl, carbazole, dibenzofuranyl, and dibenzothiopheneyl, and more preferably phenyl or diphenyl.

[0033] As a preferred embodiment of the present invention, the hydrogen atoms in the compounds of Formula I and Formula II can each be independently substituted by at least one of -D, phenyl, naphthyl, diphenyl, methyl, ethyl, propyl, butyl, methoxy, ethoxy, propoxy, or butoxy.

[0034] As a preferred embodiment of the present invention, the carbazole compounds are selected from the following substituted or unsubstituted compounds:

[0035]

[0036]

[0037] The substitution refers to the fact that each hydrogen atom in the above compound can be independently replaced by a deuterium atom.

[0038] Preferably, the carbazole compound further includes a compound in which the Si atom is replaced by a C atom; preferably, the carbazole compound is selected from any one of the following compounds:

[0039]

[0040]

[0041] It should be noted that this invention does not impose any special limitations on the preparation method of carbazole compounds; commonly used preparation methods are applicable. The following explanation uses a compound of formula I as an example:

[0042]

[0043] Ar1, Ar2, X, R1, and R2 have the same protection range as those mentioned above;

[0044] X1 and X2 are selected from any one of -F, -Cl, -Br or -I.

[0045] In a second aspect, the present invention provides an intermediate comprising compound M1:

[0046]

[0047] Ar1, Ar2, and X have the same protection scope as those mentioned above;

[0048] X2 is selected from any one of -F, -Cl, -Br or -I;

[0049] The intermediate is used to prepare carbazole compounds as described in the first aspect.

[0050] Preferably, the intermediate comprises the following compounds:

[0051]

[0052] 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;

[0053] The organic thin film layer includes carbazole compounds as described in the first aspect.

[0054] As a preferred embodiment of the present invention, the organic thin film layer includes a light-emitting layer;

[0055] The main material of the light-emitting layer includes carbazole compounds as described in the first aspect.

[0056] Preferably, the light-emitting layer is a phosphorescent light-emitting layer.

[0057] As a preferred embodiment of the present invention, the organic electroluminescent device is a blue organic electroluminescent device.

[0058] 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 compounds.

[0059] 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.

[0060] 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%.

[0061] 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.

[0062]

[0063] Wherein, M is selected from any one of Ir, Pt, Pd, Os, Ti, Zr, Hf, Eu, Tb, Tm, Cu or Au;

[0064] Y1-Y4 are each independently selected from carbon or nitrogen;

[0065] 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.

[0066] 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;

[0067] 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.

[0068] R 91 and R 92Each 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, or substituted or unsubstituted monovalent non-aromatic fused heterocyclic group.

[0069] a1 and a2 are each independent integers selected from 1 to 5, for example, they can be 1, 2, 3, 4 or 5;

[0070] b is an integer selected from 0 to 4, for example, it can be 0, 1, 2, 3 or 4;

[0071] a is selected from 1, 2, or 3;

[0072] L1 can be a monovalent organic ligand, a divalent organic ligand, or a trivalent organic ligand.

[0073] Preferably, the PD compound is selected from any one of the following compounds:

[0074]

[0075]

[0076]

[0077]

[0078]

[0079]

[0080] 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.

[0081] The hole injection layer material includes a P-type dopant. A P-type dopant is a material that coexists with the hole injection layer material in the OLED device, oxidizing the hole injection layer material and thus acting as an electron acceptor to promote 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.

[0082] 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.

[0083]

[0084] 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:

[0085]

[0086] 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;

[0087] Ar 41 Ar 42Each is independently selected from C6-C40 (e.g., C6, C8, C10, C12, C16, C20, C24, C28, C30, C32, C36, or C40, etc.) aryl groups and C6-C20 (e.g., C6, C8, C10, C12, C16, or C20, etc.) heteroaryl groups;

[0088] 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 dibenzothiophene (the substituent is phenyl), dibenzofuran-substituted thiophene, C1-C6 (e.g., C1, C2, C3, C4, C5, or C6) alkyl groups, R 41 R 42 They can be connected into a ring using a single key.

[0089] The HT-GH4 compound is selected from any one of the following compounds:

[0090]

[0091]

[0092]

[0093]

[0094]

[0095] 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:

[0096]

[0097] Wherein, L is selected from any one of C6 to 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;

[0098] 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;

[0099] Ar is selected from any one of triphenylene, fluorene anthracene, dibenzofuranyl, or dibenzothiophene;

[0100] Ar1 and Ar2 are each independently selected from any one of aryl, dibenzofuranyl, or dibenzothiophene groups containing C6 to C40 (e.g., C6, C8, C10, C12, C16, C20, C24, C28, C30, C32, C36, or C40, etc.);

[0101] Ar1 and Ar, Ar2 and Ar, and Ar1 and Ar2 can be independently connected or bridged by single bonds, O, S, CR1R2, NR.

[0102] R, R1, and R2 are each independently selected from any one of the following: C1 to C20 (e.g., C1, C2, C4, C6, C8, C10, C12, C14, C16, C18, or C20), alkyl, C6 to C40 (e.g., C6, C8, C10, C12, C16, C20, C24, C28, C30, C32, C36, or C40), aryl, dibenzofuranyl, or dibenzothiopheneyl.

[0103] In compounds of formula IB and formula IA, the H atom can be independently replaced by at least one of -F, -CN, -D (deuterium atom), C1-C6 alkyl, C1-C6 alkoxy, phenyl, biphenyl, naphthyl, phenanthryl, anthraceneyl, fluorenyl, benzo[a]fluorenyl, dibenzo[a]fluorenyl, triphenylene, fluoranyl, pyrene, perylene, spirofluorenyl, indo[a]fluorenyl, or hydrogenated benzo[a]anthryl.

[0104] Preferably, the Ar is fluoreneanthracene, where m+n>1.

[0105] 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.

[0106] 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.

[0107] Preferably, the compound of formula IB is selected from the following structures:

[0108]

[0109] Wherein, L represents phenylene;

[0110] Ar1, Ar2, and m have the same protection range as described above.

[0111] Preferably, the compound of formula IB is selected from any one of the following compounds 1-112:

[0112]

[0113]

[0114]

[0115]

[0116]

[0117] 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.

[0118] The triaryl amine compound or carbazole compound is used as the hole layer material, and the hole layer material includes the following structure:

[0119]

[0120]

[0121] Among them, Ar 601 ~Ar 609Each 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.

[0122] 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 R 702 NR 703 bridging;

[0123] 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.

[0124] 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.

[0125] 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.

[0126] In this invention, no special restrictions are placed on the electron transport layer material, which includes, but is not limited to, the following:

[0127]

[0128]

[0129]

[0130]

[0131]

[0132]

[0133]

[0134]

[0135]

[0136] 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.

[0137] 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).

[0138] Compared with the prior art, the present invention has the following beneficial effects:

[0139] This invention designs the structure of carbazole compounds 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

[0140] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be construed as limiting the scope of the invention.

[0141] Preparation Example 1

[0142] This preparation example provides intermediate P1-1, which is synthesized as follows:

[0143]

[0144] Under a nitrogen atmosphere, 13.0 g of 3-bromo-5-chloro-1,1'-biphenyl and 200 mL of tetrahydrofuran were added to a 500 mL three-necked flask. The temperature was then lowered to -78 °C, and a 0.05 mol butyllithium solution in n-hexane (1.6 M, 31 mL) was slowly added. The temperature was then maintained at -78 °C to -60 °C for 30 min. Finally, 15.0 g of... A tetrahydrofuran solution, 0.0003 mol Pd(dba) )2 0.0003 mol of anhydrous nickel chloride was slowly heated to room temperature and reacted for 2 hours, then heated to reflux and reacted for another 2 hours. The mixture was cooled, water and toluene were added and the mixture was separated. The organic layer was washed with water until neutral, dried with anhydrous magnesium sulfate, filtered to remove the desiccant, concentrated to dryness, separated by silica gel column chromatography, and eluted with petroleum ether to obtain intermediate P1-1 (15.1 g).

[0145] The obtained intermediate P1-1 was subjected to mass spectrometry analysis, and the mass-to-charge ratio (m / z) was measured to be 444.11.

[0146] Preparation Examples 2-8

[0147] Preparation Examples 2-8 each provide an intermediate. The synthesis method of the intermediate can refer to the synthesis of intermediate P1-1 provided in Preparation Example 1. The corresponding bromine derivatives are used to prepare the corresponding intermediates, as shown in Table 1 below.

[0148] The obtained intermediates were subjected to mass spectrometry detection, and the mass-to-charge ratio (m / z) data are shown in Table 1 below.

[0149] Table 1

[0150]

[0151]

[0152] Example 1

[0153] This embodiment provides compound P1, whose synthesis method is as follows:

[0154]

[0155] Under a nitrogen atmosphere, dry xylene (100 mL), intermediate P1-1 (4.4 g), intermediate P1-2 (3.5 g), Pd(dba)2 (bis(dibenzylacetone)palladium, 0.1 g), a 10% (w / w) solution of tri-tert-butylphosphine toluene (w / w) and sodium tert-butoxide (1.2 g) were added to a 250 mL three-necked flask. The mixture was heated to reflux for 8 h, cooled to room temperature, and water was added to dissolve the organic layer. 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 (v / v) to give compound P1 (5.6 g).

[0156] Mass spectrometry analysis of compound P1 showed a mass-to-charge ratio (m / z) of 740.26.

[0157] Examples 2-9

[0158] Examples 2-9 each provide a compound. The synthesis method of the compound can refer to the synthesis method of compound P1 provided in Example 1. The corresponding raw materials are used to prepare the corresponding compound, as shown in Table 2 below.

[0159] The obtained compounds were analyzed by mass spectrometry, and the mass-to-charge ratio (m / z) data are shown in Table 2 below.

[0160] Table 2

[0161]

[0162]

[0163]

[0164] Example 10

[0165] This embodiment provides compound P16, whose synthesis method is as follows:

[0166]

[0167] Under a nitrogen atmosphere, 120 mL of toluene was added to a 500 mL three-necked flask, followed by 4.5 g of intermediate P1-1, 4.6 g of intermediate P16-1, 2.12 g of sodium carbonate, and 0.1 g of dichlorodi-tert-butyl-(4-dimethylaminophenyl)phosphine palladium(II) (CAS No. 887919-35-9). The mixture was slowly heated to reflux and reacted for 8 hours. After cooling to room temperature, water was added to dissolve the organic layer. The organic layer was washed with water and dried with magnesium sulfate. After removing the desiccant, the mixture was concentrated to dryness and separated by silica gel column chromatography. Elution was performed with petroleum ether:ethyl acetate = 10:0.5 (v / v) to give compound P16 (6.9 g).

[0168] The obtained compound P16 was analyzed by mass spectrometry, and the mass-to-charge ratio (m / z) was found to be 816.30.

[0169] For other compounds whose specific synthesis methods are not listed, they can be synthesized by referring to the above examples and combining them with common knowledge in the field.

[0170] The specific structures of some of the compositions used in the following application examples and comparative application examples are as follows:

[0171]

[0172] Application Example 1

[0173] 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:

[0174] ITO / HT-1: HI-2[5%](70nm) / HT-1(35nm) / Main material: PBD-1[5%](35nm) / ETL-1(25nm) / LiF(0.5nm) / Al(150nm).

[0175] The fabrication method of the blue organic electroluminescent device is as follows:

[0176] The material was placed inside a vacuum chamber, and the vacuum was evacuated to 1×10⁻⁶. -5 ~1×10 -6 Pa is sequentially vacuum-deposited onto a cleaned ITO substrate to fabricate OLED devices.

[0177] Wherein, 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 material to form the hole injection layer.

[0178] Application Example 2-14

[0179] Application Examples 2-14 provide an 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, and the dye PBD-1 is replaced as needed (see Table 3 below). Other preparation steps and conditions are the same as in Application Example 1.

[0180] Compare and contrast examples 1-4

[0181] Comparative Application Examples 1-4 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, and the dye PBD-1 is replaced as needed (see Table 3 below). Other preparation steps and conditions are the same as in Application Example 1.

[0182] Performance testing

[0183] The luminance, driving voltage, current efficiency, and LT95 of the organic electroluminescent devices provided above were tested. The current efficiency is calculated when the luminance is 1000 cd / m². 2 The corresponding value, LT95, refers to maintaining an initial device current density of 10 mA / cm². 2 The time required for the device efficiency to drop to 95% of the efficiency corresponding to the initial current density, while remaining constant, is used. Here, current efficiency and LT95 are relative values. Specific test results are shown in Table 3 below:

[0184] Table 3

[0185] Main materials dye <![CDATA[Brightness / (cd / m 2 )]]> Current efficiency LT95 Application Example 1 P1 PBD-1 1000 1 1 Application Example 2 P1C PBD-1 1000 1.08 0.89 Application Example 3 P2 PBD-1 1000 1.16 1.27 Application Example 4 P4 PBD-1 1000 1.18 1.55 Application Example 5 P6D PBD-1 1000 1.22 1.89 Application Example 6 P10 PBD-1 1000 1.11 1.06 Application Example 7 P12 PBD-1 1000 1.99 1.57 Application Example 8 P13 PBD-1 1000 1.27 1.04 Application Example 9 P7 PBD-1 1000 1.17 1.62 Application Example 10 P8 PBD-1 1000 1.01 2.01 Application Example 11 P9 PBD-1 1000 0.87 1.43 Application Example 12 P14 PBD-1 1000 1.08 1.11 Application Example 13 P15 PBD-1 1000 1.16 1.07 Application Example 14 P7 PBD-3 1000 1.67 1.88 Comparative Application Example 1 DH1 PBD-1 1000 0.66 0.78 Comparative Application Example 2 DH2 PBD-1 1000 0.79 0.82 Comparative Application Example 3 H-4 PBD-1 1000 0.88 0.91 Comparative Application Example 4 H-4 PBD-3 1000 1.09 0.86

[0186] As can be seen from the above, this invention designs the structure of carbazole compounds to make them suitable as the main material for the light-emitting layer of organic electroluminescent devices, thereby enabling organic electroluminescent devices to have high current efficiency and long lifespan.

[0187] A comparison of Application Example 9 and Application Example 14 shows that when the dye is PBD-3, the performance of the organic electroluminescent device can be further improved.

[0188] By comparing Application Example 3 and Application Example 4, when the dye is PBD-3, the current efficiency of the organic electroluminescent device is improved, but the lifetime is reduced. Therefore, the compound of the present invention, when combined with the dye PBD-3, achieves better results.

[0189] Application Examples 15-16, Comparative Application Example 5

[0190] Application Examples 15-16 and Comparative Application Example 5 each provide a blue organic electroluminescent device. The only difference from Application Example 1 is that the main material compound P1 of the light-emitting layer is replaced with other compounds as needed (see Table 4 below), and the dye PBD-1 is replaced with PBD-3. Other preparation steps and conditions are the same as in Application Example 1.

[0191] Performance testing

[0192] The luminance, driving voltage, current efficiency, and LT95 of the organic electroluminescent devices provided above were tested. The current efficiency is calculated when the luminance is 1000 cd / m². 2 The corresponding value, LT95, refers to maintaining an initial device current density of 10 mA / cm².2 The time required for the device efficiency to drop to 95% of the efficiency corresponding to the initial current density, while the current efficiency and LT95 are relative values. Specific test results are shown in Table 4 below:

[0193] Table 4

[0194] Main materials dye <![CDATA[Brightness / (cd / m 2 )]]> Current efficiency LT95 Application Example 15 P16 PBD-3 1000 1 1 Application Example 16 P17 PBD-3 1000 1.07 0.97 Comparative Application Example 5 H-8 PBD-3 1000 0.87 0.98

[0195] As can be seen from the above, this invention designs the structure of carbazole compounds to make them suitable as the main material for the light-emitting layer of organic electroluminescent devices, thereby enabling organic electroluminescent devices to have high current efficiency and long lifespan.

[0196] The applicant declares that the detailed process flow of this invention is illustrated by the above embodiments, but this invention is not limited to the above detailed process flow, that is, it does not mean that this invention must rely on the above detailed process flow to be implemented. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of raw materials for the product of this invention, addition of auxiliary components, and selection of specific methods, etc., all fall within the protection scope and disclosure scope of this invention.

Claims

1. A carbazole-based compound, characterized by, The carbazole compounds have the structure shown in Formula I or the structure shown in Formula II: Formula I; Formula II; Ar1 is selected from any one of phenyl, naphthyl, diphenyl, carbazolyl, dibenzofuranyl, and dibenzothiopheneyl. Ar2 is selected from any one of phenyl, naphthyl, and diphenyl; R1 is selected from any one of carbazolyl, dibenzofuranyl, or dibenzothiophenel, and R2 is selected from any one of -H, phenyl, diphenyl, or naphthyl. R3 is selected from any one of phenyl, diphenyl, and naphthyl; X is selected from Si; In compounds of formula I and formula II, the hydrogen atoms can be independently replaced by -D.

2. The carbazole compound according to claim 1, characterized in that, The carbazole compounds are selected from the following substituted or unsubstituted compounds: ； The substitution refers to the fact that each hydrogen atom in the above compound can be independently replaced by a deuterium atom.

3. A carbazole compound, characterized in that, The carbazole compound is selected from any one of the following compounds: 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 。 4. An organic electroluminescent device, characterized by comprising 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 carbazole compound as described in any one of claims 1-3.

5. The organic electroluminescent device according to claim 4, characterized in that The organic thin film layer includes a light-emitting layer; The main material of the light-emitting layer includes carbazole compounds as described in any one of claims 1-3.

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