A carbazole compound and an organic electroluminescent device containing it.

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. 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] 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 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 the structure shown in Formula I:

[0007]

[0008] Ar1 to Ar3 are each independently selected from any one of C6-C40 aryl, C6-C30 heteroaryl, or C1-C12 alkyl, and any two of Ar1 to Ar3 can be linked together to form a ring by a single bond;

[0009] Ar4 is selected from any one of C6-C40 aryl or C6-C30 heteroaryl;

[0010] Ar5 and Ar6 are each independently selected from any one of -H, -D, C6-C40 aryl, or C6-C30 heteroaryl;

[0011] R1 and R2 are each independently selected from any one of -H, C6-C40 aryl, C6-C30 heteroaryl, or C1-C12 alkyl;

[0012] In compounds of formula I, each hydrogen atom can be independently substituted by at least one of -D, -F, -CN, C6-C20 aryl, C1-C12 alkyl, or C1-C12 alkoxy.

[0013] In this invention, the structure of the compound is designed to limit the types of Ar4 groups, so that Ar4 and The groups repel each other in space, increasing the steric hindrance of the entire molecule and raising T1, making it suitable as the main material for the light-emitting layer of organic electroluminescent devices, thus giving organic electroluminescent devices high current efficiency and long lifespan.

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

[0017] C6-C20 can be C6, C8, C10, C12, C16, or C20, 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 or a combination of at least two of the following: phenyl, biphenyl, terphenyl, naphthyl, anthracene, phenanthryl, fluorenyl, benzo[a]fluorenyl, dibenzo[a]fluorenyl, naphthyl, pyrene, perylene, spirofluorenyl, triphenylene, fluoranyl, hydrogenated benzo[a]anthrayl, ind[a]fluorenyl, benzo[a]ind[a]fluorenyl, dibenzo[a]ind[a]fluorenyl, naphthyl, or benzo[a]naphthyl.

[0021] As a preferred embodiment of the present invention, the C6-C30 heteroaryl group is selected from any one of dibenzofuranyl, dibenzothiophenyl, naphthobenzofuranyl, naphthobenzothiophenyl, dinaphthofuranyl, dinaphthothiophenyl, carbazoyl, phenylcarbazoyl, and carbazoylphenyl.

[0022] As a preferred embodiment of the present invention, the C6-C20 aryl group is selected from any one of phenyl, biphenyl, terphenyl, naphthyl, anthracene, phenanthryl, fluorene, triphenylene, and fluoranthracene.

[0023] As a preferred embodiment of the present invention, the C1-C12 alkyl group is selected from any one of methyl, ethyl, propyl, butyl, pentyl or hexyl.

[0024] As a preferred embodiment of the present invention, the C1-C12 alkoxy group is selected from any one of methoxy, ethoxy, propoxy, butoxy, pentoxy, or hexoxy.

[0025] As a preferred embodiment of the present invention, Ar1 to Ar3 are each independently selected from any one or a combination of at least two of phenyl, biphenyl, naphthyl, dibenzofuranyl, and carbazoleyl.

[0026] As a preferred embodiment of the present invention, the Ar4 is selected from any one or a combination of at least two of -H, phenyl, naphthyl, biphenyl, triphenylene, fluoranthyl, carbazolyl, phenylcarbazolyl, carbazolylphenyl, dibenzofuranyl, and dibenzothiophene, and is more preferably any one of -H, phenyl, naphthyl, biphenyl, carbazolyl, dibenzofuranyl, and phenylcarbazolyl.

[0027] As a preferred embodiment of the present invention, Ar5 is selected from -H and -D, and Ar6 is selected from one of phenyl, naphthyl, biphenyl, triphenylene, fluoranyl, carbazolyl, phenylcarbazolyl, carbazolyl, dibenzofuranyl, and dibenzothiophene.

[0028] Preferably, Ar6 is selected from -H or -D, and Ar5 is selected from one of phenyl, naphthyl, biphenyl, triphenylene, fluoranyl, carbazolyl, phenylcarbazolyl, carbazolyl, dibenzofuranyl, and dibenzothiophene.

[0029] Preferably, Ar5 and Ar6 are selected from -H and -D.

[0030] As a preferred embodiment of the present invention, R1 and R2 are each independently selected from any one or a combination of at least two of -H, phenyl, biphenyl, naphthyl, dibenzofuranyl, carbazoleyl, phenylcarbazoleyl, carbazoleylphenyl, and carbazoleylbiphenyl.

[0031] As a preferred embodiment of the present invention, R2 is selected from H, and R1 is selected from any one or a combination of at least two of phenyl, biphenyl, naphthyl, dibenzofuranyl, carbazoleyl, phenylcarbazoleyl, carbazoleylphenyl, and carbazoleylbiphenyl.

[0032] As a preferred embodiment of the present invention, each hydrogen atom in the compound represented by Formula I may be independently substituted by at least one of -D, -F, -CN, phenyl, naphthyl, biphenyl, carbazolyl, phenylcarbazolyl, carbazolylphenyl, methyl, ethyl, propyl, butyl, methoxy, ethoxy, propoxy, or butoxy.

[0033] As a preferred embodiment of the present invention, each hydrogen atom in the compound of Formula I may be independently substituted by at least one of -D, -F, -CN, methyl, tert-butyl, methoxy, propoxy, phenyl, naphthyl, carbazole, phenylcarbazole, and carbazolephenyl.

[0034] As a preferred embodiment of the present invention, the compound of formula I is selected from any one of the following compounds, whether substituted or unsubstituted:

[0035]

[0036]

[0037]

[0038]

[0039]

[0040] The substitution refers to the independent substitution of each hydrogen atom in the compound of formula I by a deuterium atom. Preferably, the compound of formula I is selected from any one of the following compounds:

[0041]

[0042]

[0043]

[0044] It should be noted that there are no special limitations on the preparation method of the compound of formula I in this invention, and commonly used preparation methods in the art are applicable. Examples include:

[0045]

[0046] Among them, Ar1 to Ar6 and R1 have the same protection range as described above;

[0047] X1, X2, X3, and X4 are each independently selected from -F, -Cl, -Br, and -I; and those skilled in the art can appropriately select the specific types of X1, X2, X3, and X4 based on common knowledge to make the reaction proceed better. For example, when X1 is selected as Br, X2 is selected as Cl; when X1 is selected as I, X2 can be selected as Br or Cl.

[0048] X5 is selected from -H, -F, -Cl, -Br, and -I;

[0049] In a second aspect, the present invention provides an intermediate comprising the following compounds:

[0050]

[0051] Among them, Ar1 to Ar6 and R1 have the same protection range as described above;

[0052] X2 and X4 are each independently selected from -F, -Cl, -Br, and -I;

[0053] X5 is selected from -H, -F, -Cl, -Br, and -I;

[0054] The intermediate is used to prepare carbazole compounds as described in the first aspect.

[0055] Preferably, the intermediate is selected from compounds including:

[0056]

[0057] 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;

[0058] The material of the organic thin film layer includes carbazole compounds as described in the first aspect.

[0059] 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.

[0060] Preferably, the light-emitting layer is a phosphorescent light-emitting layer.

[0061] As a preferred embodiment of the present invention, the organic electroluminescent device is a blue organic electroluminescent device.

[0062] 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.

[0063] The light-emitting layer includes a phosphorescent light-emitting layer, which includes a green phosphorescent light-emitting layer, a red phosphorescent light-emitting layer, and a yellow phosphorescent light-emitting layer.

[0064] 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%.

[0065] 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.

[0066]

[0067] Wherein, M is selected from any one of Ir, Pt, Pd, Os, Ti, Zr, Hf, Eu, Tb, Tm, Cu or Au;

[0068] Y1-Y4 are each independently selected from carbon or nitrogen;

[0069] 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.

[0070] 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;

[0071] 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.

[0072] 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.

[0073] a1 and a2 are each independent integers selected from 1 to 5, for example, they can be 1, 2, 3, 4 or 5;

[0074] b is an integer selected from 0 to 4, for example, it can be 0, 1, 2, 3 or 4;

[0075] a is selected from 1, 2, or 3;

[0076] L1 can be a monovalent organic ligand, a divalent organic ligand, or a trivalent organic ligand.

[0077] Preferably, the PD compound is selected from any one of the following compounds:

[0078]

[0079]

[0080]

[0081]

[0082]

[0083]

[0084] 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.

[0085] 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.

[0086] 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.

[0087]

[0088]

[0089] 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:

[0090]

[0091] 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;

[0092] Ar 41 Ar42 Each 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;

[0093] 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 A ring can be formed by connecting the links with a single key.

[0094] The HT-GH4 compound is selected from any one of the following compounds:

[0095]

[0096]

[0097]

[0098]

[0099]

[0100]

[0101] 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:

[0102]

[0103] 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;

[0104] 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;

[0105] Ar is selected from any one of triphenylene, fluorene anthracene, dibenzofuranyl, or dibenzothiophene;

[0106] 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.);

[0107] Ar1 and Ar, Ar2 and Ar, and Ar1 and Ar2 can be independently connected or bridged by single bonds, O, S, CR1R2, NR.

[0108] 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.

[0109] 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.

[0110] Preferably, the Ar is fluoreneanthracene, where m+n>1.

[0111] 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, or fluoranthyl.

[0112] 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.

[0113] Preferably, the compound of formula IB is selected from the following structures:

[0114]

[0115] Wherein, L represents phenylene;

[0116] Ar1, Ar2, and m have the same protection range as described above.

[0117] Preferably, the compound of formula IB is selected from any one of the following compounds 1-112:

[0118]

[0119]

[0120]

[0121]

[0122] 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.

[0123] The triaryl amine compound or carbazole compound is used as the hole layer material, and the hole layer material includes the following structure:

[0124]

[0125] 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.

[0126] 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;

[0127] 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.

[0128] 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.

[0129] 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.

[0130] In this invention, no special restrictions are placed on the electron transport layer material, which includes, but is not limited to, the following:

[0131]

[0132]

[0133]

[0134]

[0135]

[0136]

[0137]

[0138]

[0139]

[0140] 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.

[0141] 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).

[0142] Compared with the prior art, the present invention has the following beneficial effects:

[0143] 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

[0144] 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.

[0145] Preparation Example 1

[0146] This preparation example provides an intermediate M1CabBr, which is synthesized as follows:

[0147]

[0148] (1) Synthesis of intermediate M1

[0149] Under a nitrogen atmosphere, 13.5 g of 2-bromo-5-chloro-1,1'-biphenyl and 200 mL of tetrahydrofuran were added to a 1000 mL three-necked flask. The temperature was then lowered to -78 °C, and a hexane solution (1.6 M, 31 mL) containing 0.05 mol butyllithium was slowly added. The temperature was maintained at -78 °C to -60 °C for 30 min. A solution of 15.2 g of triphenylchlorosilane and 150 mL of tetrahydrofuran, 0.0003 mol Pd(dba)2, and 0.0003 mol anhydrous nickel chloride were added. The temperature was slowly raised to room temperature and reacted for 2 h, then refluxed for another 2 h. The mixture was cooled, and water and toluene were added to separate the layers. The organic layer was washed with water until neutral, dried over 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 M1 (13.2 g).

[0150] The obtained intermediate M1 was subjected to mass spectrometry analysis, and the mass-to-charge ratio (m / z) was measured to be 446.13.

[0151] (2) Synthesis of intermediate M1Cab

[0152] Under a nitrogen atmosphere, 100 mL of dry xylene, 9.0 g of intermediate M1, 3.4 g of carbazole, 0.1 g of Pd(dba)2 (bis(dibenzylacetone)palladium), 10% (w / w) tri-tert-butylphosphine toluene solution (w / w) (0.8 g of tri-tert-butylphosphine solution), and 2.9 g of sodium tert-butoxide 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 mixture. The organic layer was then washed with water until neutral, dried with magnesium sulfate, filtered to remove magnesium sulfate, concentrated to dryness, separated by silica gel column chromatography, and eluted with petroleum ether to obtain intermediate M1Cab (8.6 g).

[0153] Mass spectrometry analysis of intermediate M1Cab revealed a mass-to-charge ratio (m / z) of 577.22.

[0154] (3) Synthesis of intermediate M1CabBr

[0155] Under a nitrogen atmosphere, 5.8 g of intermediate M1Cab and 70 mL of LDMF were added to a 500 mL three-necked flask. 1.8 g of solid NBS (N-bromosuccinimide) was added in portions at 20-25 °C. After the addition was complete, the mixture was stirred at 20-25 °C for 8 hours. Water was added, and the solid was filtered. After drying, it was crystallized in a mixed solvent of ethanol and chlorobenzene to obtain intermediate M1CabBr (4.9 g).

[0156] Mass spectrometry analysis of the intermediate M1CabBr revealed two peaks with the largest mass-to-charge ratio (m / z) at 655.13 and 657.13, with essentially the same abundance.

[0157] Preparation Example 2

[0158] This preparation example provides an intermediate M1CabBr2, which is synthesized as follows:

[0159]

[0160] Under a nitrogen atmosphere, 5.8 g of intermediate M1Cab and 70 mL of DMF were added to a 500 mL three-necked flask. 3.6 g of solid NBS (N-bromosuccinimide) was added in portions at 20-25 °C. After the addition was complete, the mixture was stirred at 20-25 °C for 8 hours. Water was added, and the solid was filtered. After drying, it was crystallized in a mixed solvent of ethanol and chlorobenzene to obtain intermediate M1CabBr2 (5.3 g).

[0161] Mass spectrometry analysis of intermediate M1CabBr2 revealed the following peaks with the highest mass-to-charge ratio (m / z): 735.04 (100% abundance), 737.04, and 733.04 (approximately 50% abundance).

[0162] Preparation Examples 3-8

[0163] Preparation Examples 3-8 each provide an intermediate. The synthesis method of the intermediate is the same as that of intermediate M1 provided in Preparation Example 1. The only difference is the specific choice of the brominated product, as detailed in Table 1 below.

[0164] The obtained intermediates were subjected to mass spectrometry analysis, and their mass-to-charge ratio (m / z) data are detailed in Table 1 below.

[0165] Table 1

[0166]

[0167] Synthesis Example 1

[0168] This synthetic example provides compound P1, which is synthesized as follows:

[0169]

[0170] Under a nitrogen atmosphere, dry xylene (100 mL), intermediate M1 (4.5 g), intermediate P1-1 (3.3 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 temperature and reacted for 8 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 (v / v) to give compound P1 (5.8 g).

[0171] Mass spectrometry analysis of compound P1 showed a mass-to-charge ratio (m / z) of 742.28.

[0172] Synthesis Examples 2-18

[0173] Synthesis Examples 2-18 each provide a compound. The synthesis method of the compound is the same as that of compound P1 provided in Synthesis Example 1. The following compounds are prepared by reacting the corresponding raw materials, as detailed in Table 2 below.

[0174] The obtained compounds were analyzed by mass spectrometry, and their mass-to-charge ratio (m / z) data are detailed in Table 2 below.

[0175] Table 2

[0176]

[0177]

[0178]

[0179]

[0180]

[0181] Synthesis Example 19

[0182] This synthetic example provides compound P4, whose synthetic method is as follows:

[0183]

[0184] Under a nitrogen atmosphere, 200 mL of toluene, 90 mL of ethanol, and 30 mL of water were added sequentially to a 500 mL three-necked flask. Then, 6.5 g of intermediate M1CabBr, 4.5 g of intermediate P4-1, 2.12 g of sodium carbonate, and 0.23 g of tetrakis(triphenylphosphine)palladium were added. The mixture was slowly heated to reflux temperature and reacted for 8 h. After cooling to room temperature, water was added to separate 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. The elution was performed with petroleum ether:ethyl acetate = 10:0.5 (v / v) to give compound P4 (7.7 g).

[0185] The obtained compound P4 was analyzed by mass spectrometry, and the mass-to-charge ratio (m / z) was found to be 983.37.

[0186] Synthesis Examples 20-26

[0187] Synthesis Examples 20-26 each provide a compound. The synthesis method of the compound can refer to the synthesis method provided in Synthesis Example 19. The corresponding boric acid compound and the corresponding bromide compound are reacted to obtain the corresponding compound, as shown in Table 3 below.

[0188] The obtained compounds were analyzed by mass spectrometry, and the mass-to-charge ratio (m / z) data are shown in Table 3 below.

[0189] Table 3

[0190]

[0191]

[0192] 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.

[0193] The specific structures of some of the compounds used in the following application examples and comparative application examples are as follows:

[0194]

[0195]

[0196] Application Example 1

[0197] 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:

[0198] 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).

[0199] The fabrication method of the blue organic electroluminescent device is as follows:

[0200] 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.

[0201] 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.

[0202] Application Example 2-12

[0203] Application Examples 2-12 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 4 below). The other preparation steps and conditions are the same as in Application Example 1.

[0204] Comparative Application Examples 1-3

[0205] 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 4 below), and the other preparation steps and conditions are the same as in Application Example 1.

[0206] Performance testing

[0207] 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:

[0208] Table 4

[0209] Main materials dye <![CDATA[Luminance / (cd / m 2 )]]> Current efficiency LT95 Application Example 1 P1 PBD-1 1000 1 1 Application Example 2 P1D PBD-1 1000 0.97 1.26 Application Example 3 P2 PBD-1 1000 1.23 0.87 Application Example 4 P3 PBD-1 1000 1.11 0.76 Application Example 5 P7D PBD-1 1000 1.09 1.35 Application Example 6 P13 PBD-1 1000 1.22 1.03 Application Example 7 P14 PBD-1 1000 1.26 1.18 Application Example 8 P15 PBD-1 1000 1.09 1.43 Application Example 9 P16 PBD-1 1000 1.15 1.79 Application Example 10 P21 PBD-1 1000 1.36 1.67 Application Example 11 P22 PBD-1 1000 1.06 1.56 Application Example 12 P24 PBD-1 1000 1.02 2.09 Comparative Application Example 1 DH2 PBD-1 1000 0.89 0.61 Comparative Application Example 2 DH3 PBD-1 1000 0.65 0.72 Comparative Application Example 3 DH1 PBD-1 1000 0.62 0.47

[0210] 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.

[0211] Application Examples 13-18, Comparative Application Examples 4-6

[0212] Application Examples 13-18 and Comparative Application Examples 4-6 each 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 with compound PBD-3 (see Table 5 below for details). The other preparation steps and conditions are the same as in Application Example 1.

[0213] Performance testing

[0214] 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 5 below:

[0215] Table 5

[0216] Main materials dye <![CDATA[Brightness / (cd / m 2 )]]> Current efficiency LT95 Application Example 13 P12 PBD-3 1000 1 1 Application Example 14 P17 PBD-3 1000 0.87 1.29 Application Example 15 P18 PBD-3 1000 1.78 1.90 Application Example 16 P19 PBD-3 1000 1.26 2.09 Application Example 17 P25 PBD-3 1000 1.99 1.87 Application Example 18 P11 PBD-3 1000 1.09 1.11 Comparative Application Example 4 DH1 PBD-3 1000 0.76 0.66 Comparative Application Example 5 DH4 PBD-3 1000 0.80 0.97 Comparative Application Example 6 DH5 PBD-3 1000 0.51 0.47

[0217] 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.

[0218] Application Examples 19-21, Comparative Application Example 7

[0219] Application Examples 19-21 and Comparative Application Example 7 each 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 with compound PBD-3 (see Table 6 below). The other preparation steps and conditions are the same as in Application Example 1.

[0220] Performance testing

[0221] 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. 2The 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 6 below:

[0222] Table 6

[0223] Main materials dye <![CDATA[Brightness / (cd / m 2 )]]> Current efficiency LT95 Application Example 19 P4 PBD-3 1000 1 1 Application Example 20 P5 PBD-3 1000 1.57 0.78 Application Example 21 P9 PBD-3 1000 1.60 1.76 Comparative Application Example 7 DH6 PBD-3 1000 0.88 0.39

[0224] 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.

[0225] 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 compound, characterized in that, The carbazole compounds have the structure shown in Formula I: Equation I; Ar1 to Ar3 are selected from phenyl groups; Ar4 is selected from any one or a combination of at least two of the following: phenyl, naphthyl, biphenyl, triphenylene, carbazolyl, phenylcarbazolyl, dibenzofuranyl, and dibenzothiophene. Ar5 is selected from any one of -H, -D, phenyl or carbazole groups; Ar6 is selected from any one of -H, -D or phenyl; R1 is selected from any one or a combination of at least two of -H, phenyl, dibenzofuranyl, carbazoleyl, phenylcarbazoleyl, carbazoleylphenyl, and carbazoleylbiphenyl; The R2 is selected from any one of -H, phenyl, or carbazole group; In compounds of formula I, each hydrogen atom can be independently substituted by at least one of -D and -F.

2. The carbazole compound according to claim 1, characterized in that, The Ar4 is selected from any one of phenyl, naphthyl, biphenyl, carbazolyl, dibenzofuranyl, and phenylcarbazolyl.

3. The carbazole compound according to claim 1, characterized in that, The Ar5 is selected from -H and -D, and the Ar6 is selected from phenyl.

4. The carbazole compound according to claim 1, characterized in that, Ar6 is selected from -H and -D, and Ar5 is selected from phenyl and carbazole groups.

5. The carbazole compound according to claim 1, characterized in that, Ar5 and Ar6 are selected from -H and -D, respectively.

6. The carbazole compound according to claim 1, characterized in that, R2 is selected from H, and R1 is selected from any one or a combination of at least two of phenyl, dibenzofuranyl, carbazoyl, phenylcarbazoyl, carbazoylphenyl, and carbazoylbiphenyl.

7. The carbazole compound according to claim 1, characterized in that, The compound of formula I is selected from any one of the following compounds, substituted or unsubstituted: ； The substitution refers to the fact that each hydrogen atom in the compound of formula I can be independently replaced by a deuterium atom.

8. A carbazole compound, characterized in that, The carbazole compound is selected from any one of the following compounds: 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 。 9. An intermediate, characterized in that, The intermediate includes the following compounds: 、 、 ； Ar1 to Ar6 and R1 have the same protection scope as claim 1; X2 and X4 are each independently selected from -F, -Cl, -Br, and -I; X5 is selected from -H, -F, -Cl, -Br, and -I; The intermediate is used to prepare the carbazole compound as described in any one of claims 1-8.

10. The intermediate according to claim 9, characterized in that, The intermediate is selected from the following compounds: 、 、 。 11. 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 material of the organic thin film layer includes carbazole compounds as described in any one of claims 1-8.

12. The organic electroluminescent device according to claim 11, characterized in that, 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 any one of claims 1-8.

13. The organic electroluminescent device according to claim 12, characterized in that, The light-emitting layer is a phosphorescent light-emitting layer.

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