Carbazole compound and organic electroluminescent device

Abstract

The invention provides a carbazole compound and an organic electroluminescent device. The carbazole compound comprises a compound with a structure as shown in a formula I. The structure of the compound is designed, so that the compound is suitable for being used as a main body material of a light-emitting layer of the organic light-emitting device, and the organic light-emitting device has relatively high current efficiency and relatively long service life.

Description

Technical Field

[0001] The invention belongs to the technical field of organic electroluminescent materials, and particularly relates to a carbazole compound and an organic electroluminescent device. Background Art

[0002] Compared with other flat panel displays (for example, liquid crystal displays (LCDs), plasma display panels (PDPs), field emission displays (FEDs), etc.), organic electroluminescent devices (OLEDs) have a simpler structure, various processing advantages, higher brightness, excellent viewing angle characteristics, faster response speeds, and lower driving voltages. Therefore, they have been fully developed to be used as light sources for flat panel displays (for example, wall-mounted TVs, etc.), or as backlight units for displays, illuminators, billboards, etc.

[0003] The structure of an organic electroluminescent device specifically consists of an anode, a cathode, and an organic layer between them. To improve the efficiency and stability of organic electroluminescent elements, the organic material layer can be composed of multiple layers of different materials. To meet the increasing demands for OLED devices, the field urgently needs to develop a wider variety of materials to improve OLED device performance in terms of current efficiency, lifespan, and other aspects. Summary of the Invention

[0004] In response to the shortcomings of the prior art, the present invention provides a carbazole compound and an organic electroluminescent device. The present invention designs the structure of the carbazole compound to make it suitable as a host material for the light-emitting layer of an organic electroluminescent device, thereby enabling the organic electroluminescent device to have higher current efficiency and longer life.

[0005] To achieve this object, the present invention adopts the following technical solutions:

[0006] In a first aspect, the present invention provides a carbazole compound, wherein the carbazole compound includes a compound having a structure shown in the following 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;

[0009] Ar4 is selected from any one of C6-C40 aryl, C6-C30 heteroaryl, C1-C12 alkyl or triphenylsilyl;

[0010] Ar is selected from any one of a single bond, a C6-C40 arylene group, or a C6-C30 heteroarylene group;

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

[0012] X is selected from C or Si;

[0013] Z is selected from O and S;

[0014] The hydrogen atoms in the compound of formula I may each independently be substituted by at least one of a deuterium atom, -F, -CN, a C6-C20 aryl group, a C1-C12 alkyl group, or a C1-C12 alkoxy group.

[0015] In the present invention, the structure of the carbazole compound is designed to make it suitable as the main material of the light-emitting layer of the organic electroluminescent device, so that the organic electroluminescent device has higher current efficiency and longer life.

[0016] It should be noted that, in the present invention, "D" represents a deuterium atom, and the same shall apply hereinafter.

[0017] In the present invention, C6-C40 can be C6, C8, C10, C12, C16, C20, C24, C28, C30, C32, C36 or C40, etc.

[0018] C6-C30 can be C6, C8, C10, C12, C16, C20, C24, C28 or C30, etc.

[0019] C1~C12 can be C1, C2, C4, C6, C8, C10 or C12, etc.

[0020] C6-C20 can be C6, C8, C10, C12, C16 or C20, etc.

[0021] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. Through the following preferred technical solutions, the objectives and beneficial effects of the present invention can be better achieved and realized.

[0022] As a preferred technical solution of the present invention, the C6-C40 aromatic group is selected from any one or a combination of at least two of phenyl, biphenyl, terphenyl, naphthyl, anthracenyl, phenanthrenyl, fluorenyl, benzofluorenyl, dibenzofluorenyl, naphthacenyl, pyrenyl, peryl, spirofluorenyl, triphenylene, fluoranthenyl, hydrogenated benzanthryl, indenofluorenyl, benzoindenofluorenyl, dibenzoindenofluorenyl, naphthacenyl or benzonaphthofluorenyl.

[0023] As a preferred technical solution of the present invention, the C6-C40 arylene group is selected from any one of phenylene, biphenylene, terphenylene, naphthylene, anthracene, phenanthrenyl, fluorenylene, benzofluorenylene, dibenzofluorenylene, naphthofluorenylene, pyrenylene, perylene, spirofluorenylene, triphenylene, fluoranthenylene, hydrogenated benzoanthrylene, indenofluorenylene, benzoindenofluorenylene, dibenzoindenofluorenylene, naphthofluorenylene or benzonaphthofluorenylene, or a combination of at least two thereof.

[0024] As a preferred technical solution of the present invention, the C6-C30 heteroaryl group is selected from any one of dibenzofuranyl, dibenzothiophenyl, naphthobenzofuranyl, naphthobenzothiophenyl, dinaphthofuranyl, dinaphthothiophenyl, carbazolyl, phenylcarbazolyl, and carbazolylphenyl.

[0025] As a preferred technical solution of the present invention, the C6-C30 heteroaryl group is selected from any one of dibenzofuranyl, dibenzothiophenyl, naphthobenzofuranyl, naphthobenzothiophenyl, dinaphthofuranyl, dinaphthothiophenyl, carbazolyl, phenylcarbazolyl, and carbazolylphenyl.

[0026] As a preferred technical solution of the present invention, the C6-C20 aryl group is selected from any one of phenyl, biphenyl, terphenyl, naphthyl, anthracenyl, phenanthrenyl, fluorenyl, triphenylene, and fluoranthenyl.

[0027] As a preferred technical solution of the present invention, the C1-C12 alkyl group is selected from any one of methyl, ethyl, propyl, butyl, pentyl or hexyl.

[0028] As a preferred technical solution of the present invention, the C1-C12 alkoxy group is selected from any one of methoxy, ethoxy, propoxy, butoxy, pentyloxy or hexyloxy.

[0029] As a preferred technical solution of the present invention, Ar1 to Ar3 are each independently selected from any one of phenyl, biphenyl, naphthyl, dibenzofuranyl, and carbazolyl.

[0030] As a preferred technical solution of the present invention, Ar4 is selected from any one of phenyl, biphenyl, naphthyl, dibenzofuranyl, carbazolyl, and triphenylsilyl, and is further preferably any one of phenyl, naphthyl, and triphenylsilyl.

[0031] As a preferred technical solution of the present invention, Ar is selected from any one of a single bond, a phenylene group, a naphthylene group, a biphenylene group, a triphenylene group, a fluoranthenyl group, a carbazolyl group, a phenylene carbazolyl group, a carbazolylphenyl group, a dibenzofuranyl group, and a dibenzothiophenyl group, and is further preferably any one of a single bond, a phenylene group, a biphenylene group, a dibenzofuranyl group, and a carbazolyl group.

[0032] As a preferred technical solution of the present invention, R1 and R2 are each independently selected from any one of -H, methyl, ethyl, propyl, tert-butyl, phenyl, biphenyl, naphthyl, triphenylene, dibenzofuranyl, dibenzothiophenyl, carbazolyl, and carbazolyl, or a combination of at least two thereof, and are further preferably any one of -H, methyl, tert-butyl, phenyl, naphthyl, biphenyl, triphenylene, carbazolyl, dibenzothiophenyl, and dibenzofuranyl.

[0033] As a preferred technical solution of the present invention, R2 is selected from H, and R1 is selected from any one of -H, methyl, tert-butyl, phenyl, naphthyl, biphenyl, triphenylene, carbazolyl, dibenzothiophenyl, and dibenzofuranyl.

[0034] As a preferred technical solution of the present invention, Ar4 is selected from triphenylsilyl.

[0035] As a preferred technical solution of the present invention, the hydrogen atoms in the compound of formula I can each independently be substituted by at least one of -D, -F, -CN, phenyl, naphthyl, biphenyl, carbazolyl, phenylcarbazolyl, carbazolylphenyl, methyl, ethyl, propyl, butyl, methoxy, ethoxy, propoxy or butoxy.

[0036] Preferably, the hydrogen atoms in the compound of formula I can each independently be substituted by at least one of -D, -F, -CN, methyl, tert-butyl, methoxy, propoxy, naphthyl, phenyl, carbazolyl, phenylcarbazolyl, and carbazolylphenyl.

[0037] As a preferred technical solution of the present invention, the compound of formula I includes any one of the following substituted or unsubstituted compounds:

[0038]

[0039]

[0040]

[0041] The substitution means that each hydrogen atom in the compound of formula I can be independently replaced by a deuterium atom.

[0042] Preferably, the compound of formula I further comprises the dibenzofuran group in the above compound Replaced by dibenzothiophene group The dotted line represents the connection site. The following are examples:

[0043] The compound dibenzofuran groups in Replaced by dibenzothiophene group The compound was obtained The compound dibenzofuran groups in Replaced by dibenzothiophene group The compound was obtained Other explanations can be given similarly.

[0044] Preferably, the compound of formula I also includes a compound wherein the Si atom in the above compound is replaced by a C atom, that is, Group replaced by The dotted line represents the connection site. Examples are as follows:

[0045] The compound The compound obtained by replacing the Si atom with a C atom is The compound The compound obtained by replacing the Si atom with a C atom is Other explanations can be given similarly.

[0046] Preferably, the compound of formula I is selected from any one of the following compounds:

[0047]

[0048]

[0049] It should be noted that the present invention does not have any special limitations on the preparation method of the compound of formula I, and any commonly used preparation method in the art is applicable. For example, the present invention also provides a preparation method of the compound of formula I:

[0050] (1) When Ar is not selected from a single bond, the first synthesis method:

[0051]

[0052] wherein X1 and X2 are each independently selected from any one of F, chlorine, bromine or iodine, and the reactivity of X1 is greater than the reactivity of X2;

[0053] Ar1 to Ar3, Ar4, Ar, R1, R2, X, and Z have the same meanings as above;

[0054] (2) When Ar is not selected from a single bond, the second synthesis method:

[0055]

[0056] wherein X1 and X2 are independently selected from any one of F, chlorine, bromine or iodine, and the reactivity of X2 is greater than the reactivity of X1;

[0057] Ar1 to Ar3, Ar4, Ar, R1, R2, X, and Z have the same meanings as above;

[0058] (3) When Ar is selected from a single bond, the first synthesis method:

[0059]

[0060] wherein X1, X2, and X3 are independently selected from any one of F, chlorine, bromine, or iodine, and the reactivity of X1 is greater than the reactivity of X2; the reactivity of X3 is greater than the reactivity of X2;

[0061] Ar1 to Ar3, Ar4, R1, R2, X, and Z have the same meanings as above;

[0062] (4) When Ar is selected from a single bond, the second synthesis method:

[0063]

[0064] wherein X1, X2, and X3 are independently selected from F, chlorine, bromine, and iodine, and the reactivity of X2 is greater than the reactivity of X1; the reactivity of X3 is greater than the reactivity of X1;

[0065] Ar1 to Ar3, Ar4, R1, R2, X, and Z have the same definitions as above.

[0066] In a second aspect, the present invention provides an intermediate comprising the following compound:

[0067]

[0068] Wherein, Ar1 to Ar3, Ar4, R1, R2, X, and Z have the same definitions as above;

[0069] X1 and X2 are each independently selected from any one of F, chlorine, bromine or iodine;

[0070] The intermediate is used to prepare the carbazole compound as described in the first aspect.

[0071] Preferably, the intermediate includes the following compounds:

[0072]

[0073] In a third aspect, the present invention provides an organic electroluminescent device, comprising an anode, a cathode, and an organic thin film layer disposed between the anode and the cathode;

[0074] The organic thin film layer includes the carbazole compound as described in the first aspect.

[0075] As a preferred technical solution of the present invention, the organic thin film layer includes a light-emitting layer, and the main material of the light-emitting layer includes the carbazole compound as described in the first aspect.

[0076] Preferably, the light-emitting layer is a phosphorescent light-emitting layer.

[0077] As a preferred technical solution of the present invention, the organic electroluminescent device is a blue organic electroluminescent device.

[0078] The luminescent layer of the present invention includes a luminescent layer host material and a dopant material, wherein the dopant material is also called a dye or a phosphorescent luminescent material. The luminescent layer host material can be a single compound or a mixture of two or more compounds.

[0079] The light-emitting layer includes a phosphorescent light-emitting layer, and the phosphorescent light-emitting layer includes a green phosphorescent light-emitting layer, a red phosphorescent light-emitting layer, a yellow phosphorescent light-emitting layer, and a blue phosphorescent light-emitting layer.

[0080] The volume percentage of the main material in the phosphorescent light-emitting layer is 60% to 99.9% (for example, it can be 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98% or 99.9%, etc.), preferably 70% to 99.5%, and more preferably 85% to 95%.

[0081] In the present invention, the doping material for the light-emitting layer may be a phosphorescent material, which is also called a triplet light-emitting material and refers to a substance that emits light from a triplet excited state. The specific choice of phosphorescent material in the present invention is not particularly limited, and any doping material for the light-emitting layer commonly used in the art is applicable, including but not limited to compounds having a structure as shown in Formula PD:

[0082]

[0083] wherein M is selected from any one of Ir, Pt, Pd, Os, Ti, Zr, Hf, Eu, Tb, Tm, Cu, or Au;

[0084] Y1-Y4 are each independently selected from carbon or nitrogen;

[0085] Y1 and Y2 can be connected by a single bond or a double bond, and Y3 and Y4 can be connected by a single bond or a double bond;

[0086] Cy1 and Cy2 are each independently selected from any one of phenyl, naphthyl, fluorenyl, spirofluorenyl, indenyl, pyrrolyl, thienyl, furyl, imidazolyl, pyrazolyl, thiazolyl, isothiazolyl, pyridyl, pyrazinyl, pyrimidinyl, pyridazinyl, quinolyl, isoquinolyl, benzoquinolyl, quinoxalinyl, quinazolinyl, carbazolyl, benzimidazolyl, benzofuranyl, benzothiophenyl, isobenzothiophenyl, benzimidazolyl, benzoxazolyl, triazolyl, tetrazolyl, oxadiazolyl, triazinyl, dibenzofuranyl, dibenzothiophenyl, N-heterocarbazolyl, N-heterodibenzofuranyl, wherein Cy1 and Cy2 may be optionally linked to each other via a single bond or an organic linking group;

[0087] Any two ligands of M, or more than two ligands, may be connected by a single bond or a double bond, or may be bridged by O or S, or may be connected by any chemical group or chemical structure to form a structural form that conforms to chemical principles;

[0088] R 91 and R 92Each is independently selected from -H, -D, -F, -Cl, -Br, -I, hydroxyl, cyano, nitro, amino, amidino, hydrazine, hydrazone, carboxylic acid, carboxylate, sulfonic acid, sulfonate, phosphoric acid, phosphate, -SF5, substituted or unsubstituted C1-C60 (for example, C1, C5, C10, C15, C20, C25, C30, C35, C40, C45, C50, C55 or C60, etc.) alkyl, substituted or unsubstituted C2-C6 C2, C5, C10, C15, C20, C25, C30, C35, C40, C45, C50, C55 or C60, etc.) alkenyl, substituted or unsubstituted C2-C60 (for example, C2, C5, C10, C15, C20, C25, C30, C35, C40, C45, C50, C55 or C60, etc.) alkynyl, substituted or unsubstituted C1-C60 (for example, C1, C5, C10, C15, C20, C25, C30, C35, C40, C45, C50, C55 or C60, etc.) C2-C10 (for example, C2, C3, C4, C5, C6, C7, C8, C9 or C10) heterocycloalkyl, substituted or unsubstituted C6-C60 (for example, C6, C12, C15, C18, C24, C30, C32, C36, C40, C42, C54 or C60) aryl, substituted or unsubstituted C6-C60 (for example, 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 C6, C12, C15, C18, C24, C30, C32, C36, C40, C42, C54 or C60) aryloxy, substituted or unsubstituted C6-C60 (for example, it can be C6, C12, C15, C18, C24, C30, C32, C36, C40, C42, C54 or C60) arylthio, substituted or unsubstituted monovalent non-aromatic fused polycyclic group, and substituted or unsubstituted monovalent non-aromatic fused heteropolycyclic group.

[0089] a1 and a2 are each independently an integer selected from 1 to 5, for example, 1, 2, 3, 4 or 5;

[0090] b is an integer selected from 0-4, for example, 0, 1, 2, 3 or 4;

[0091] a is selected from 1, 2 or 3;

[0092] L1 is a monovalent organic ligand, a divalent organic ligand or a trivalent organic ligand.

[0093] Preferably, the compound of formula PD is selected from any one of the following compounds:

[0094]

[0095]

[0096]

[0097]

[0098]

[0099]

[0100] In the present invention, the organic thin film layer includes a hole layer, and the hole layer includes a hole injection layer, a hole transport layer and an electron blocking layer.

[0101] 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 is capable of oxidizing the hole injection layer material, thereby acting as an electron acceptor and promoting the migration of holes from the hole injection layer toward the anode. In the present invention, the difference between the absolute value of the LUMO of the P-type dopant and the absolute value of the HOMO of the hole layer material is greater than -0.2V, preferably greater than -0.1eV, more preferably greater than 0eV, more preferably greater than 0.1eV, and even more preferably greater than 0.2eV.

[0102] The P-type dopant is present in the hole injection layer at a volume percentage of 1% to 10% (e.g., 1%, 2%, 4%, 6%, 8%, or 10%). In the present invention, there is no particular limitation on the type of the P-type dopant. For example, compounds D-1 to D-13 disclosed in CN113728453A or compounds HI-1 to HI-9 described below may be used:

[0103]

[0104] In the present invention, the hole layer material (including the hole injection layer, the hole transport layer and the electron blocking layer) has a structure shown in the following formula HT-GH4:

[0105]

[0106] Among them, L 41 is selected from a single bond, a C6-C40 (e.g., C6, C8, C10, C12, C16, C20, C24, C28, C30, C32, C36, or C40, etc.) aryl group, a C6-C20 (e.g., C6, C8, C10, C12, C16, or C20, etc.) heteroaryl group;

[0107] Ar 41 、Ar 42each independently 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;

[0108] X is selected from CR 41 R 42 or NR 43 , where R 41 、R 42 、R 43 Each independently selected from substituted or unsubstituted phenyl (the substituted substituent is selected from C1-C6 (for example, C1, C2, C3, C4, C5 or C6) alkyl, C1-C6 (for example, C1, C2, C3, C4, C5 or C6) alkoxy, dibenzofuranyl), naphthyl, triphenylene, fluoranthenyl, 9,9-dimethylfluorenyl, biphenyl, substituted or unsubstituted dibenzofuranyl (the substituted substituent is phenyl), substituted or unsubstituted dibenzothiophenyl (the substituted substituent is phenyl), dibenzofuran-substituted thienyl, C1-C6 (for example, C1, C2, C3, C4, C5 or C6) alkyl, any one of R 41 、R 42 They can be linked to form rings via single bonds.

[0109] The compound of formula HT-GH4 is selected from any one of the following compounds:

[0110]

[0111]

[0112]

[0113]

[0114]

[0115] In the present invention, the hole layer material (including the hole injection layer, the hole transport layer and the electron blocking layer) further includes a compound having a structure as shown in the following formula IA or a compound having a structure as shown in the following formula IB:

[0116]

[0117] wherein L is selected from any one of a C6-C40 (e.g., C6, C8, C10, C12, C16, C20, C24, C28, C30, C32, C36, or C40) arylene group, a dibenzofuranyl group, or a dibenzothiophenyl group;

[0118] m is selected from an integer between 0 and 4 (for example, 0, 1, 2, 3 or 4), and n is selected from 0 or 1;

[0119] Ar is selected from any one of triphenylene, fluoranthenylene, dibenzofuranylene or dibenzothiophenylene;

[0120] Ar1 and Ar2 are each independently selected from any one of a C6-C40 (e.g., C6, C8, C10, C12, C16, C20, C24, C28, C30, C32, C36, or C40) aryl group, a dibenzofuranyl group, or a dibenzothiophenyl group;

[0121] Ar1 and Ar, Ar2 and Ar, and Ar1 and Ar2 can each independently be connected or bridged by a single bond, O, S, CR1R2, or NR.

[0122] R, R1, and R2 are each independently selected from any one of a C1-C20 (e.g., C1, C2, C4, C6, C8, C10, C12, C14, C16, C18, or C20) alkyl group, a C6-C40 (e.g., C6, C8, C10, C12, C16, C20, C24, C28, C30, C32, C36, or C40) aryl group, a dibenzofuranyl group, or a dibenzothiophenyl group;

[0123] H in the compound of formula IB and the compound of formula IA may each independently be replaced by at least one of -F, -CN, -D (deuterium atom), C1-C6 alkyl, C1-C6 alkoxy, phenyl, biphenyl, naphthyl, phenanthrenyl, anthracenyl, fluorenyl, benzofluorenyl, dibenzofluorenyl, triphenylene, fluoranthenyl, pyrenyl, perylenyl, spirofluorenyl, indenofluorenyl or hydrogenated benzanthryl.

[0124] Preferably, Ar is a fluoranthenyl group, and m+n>1.

[0125] Preferably, H in the compound of formula IB and the compound of formula IA can be replaced by at least one of -F, -CN, -D, C1-C3 alkyl (for example, methyl, ethyl or propyl), C1-C3 alkoxy (for example, methoxy, ethoxy or propoxy), phenyl, biphenyl, triphenylene, and fluoranthene.

[0126] Preferably, L, Ar1, and Ar2 are each independently selected from at least one of phenyl, biphenyl, naphthyl, phenanthryl, anthracenyl, fluorenyl, benzofluorenyl, dibenzofluorenyl, triphenylene, fluoranthenyl, pyrenyl, perylene, spirofluorenyl, indenofluorenyl, and hydrogenated benzanthryl.

[0127] Preferably, the compound of formula IB is selected from the following structures:

[0128]

[0129] Wherein, L is phenylene;

[0130] Ar1, Ar2, and m have the same protection scope as above.

[0131] Preferably, the compound of formula IB is selected from any one of the following compounds:

[0132]

[0133]

[0134] In the OLED device provided by the present invention, the hole layer material, in addition to the compound of formula HT-GH4, the compound of formula IB, and the compound of formula IA, may also include conventional hole materials in the art, without particular limitation. Exemplary examples include, but are not limited to, triarylamine compounds or carbazole compounds. Triarylamine compounds or carbazole compounds containing more than 3 N atoms are preferred, because the HOMO of triarylamine compounds or carbazole compounds containing more than 3 N atoms is higher (the absolute value is smaller), and they are more suitable for use as hole injection layer materials. Triarylamine compounds or carbazole compounds containing 2 or 1 N atoms can be used as hole transport layer materials. Some compounds or carbazole compounds containing 1 N atom, if they have a higher LUMO, can also be used as electron blocking layer materials.

[0135] The triarylamine compound or the carbazole compound is used as the hole layer material, and the hole layer material includes the following structure:

[0136]

[0137] Among them, Ar 601 ~Ar 609 Each independently selected from a substituted or unsubstituted C6-C40 (for example, C6, C8, C10, C12, C16, C20, C24, C28, C30, C32, C36 or C40, etc.) aryl group, a substituted or unsubstituted dibenzofuranyl group, a substituted or unsubstituted dibenzothiophenyl group, a substituted or unsubstituted naphthobenzofuranyl group, a substituted or unsubstituted naphthobenzothiophenyl group, a substituted or unsubstituted dinaphthofuranyl group, or a substituted or unsubstituted dinaphthothiophenyl group;

[0138] And Ar 601 ~Ar 609 Ar atoms adjacent to or connected to the same N atom 601 ~Ar609 , can be connected by single key or through O, S, CR 701 R 702 NR 703 bridging;

[0139] R 701 、R 702 、R 703 is selected from C6-C40 (e.g., C6, C8, C10, C12, C16, C20, C24, C28, C30, C32, C36, or C40) aromatic groups, C6-C20 (e.g., C6, C8, C10, C12, C16, or C20) heteroaryl groups, C1-C6 (e.g., C1, C2, C3, C4, C5, or C6) alkyl groups, and R 701 、R 702 Can connect via one-touch.

[0140] A hole-blocking layer (HBL) can confine holes and / or excitons within the emitting layer (EL) to improve device current efficiency and lifetime. Compared to the EL material closest to the HBL interface, the HBL material has a lower HOMO (larger absolute value) and / or higher triplet energy.

[0141] The electron transport layer (ETL) may include a material capable of transporting electrons. The electron transport layer may be intrinsic (undoped) or doped, and doping may be used to enhance conductivity. In the present invention, there is no particular restriction on the ETL material, and any metal complex or organic compound may be used as long as it can transport electrons. Generally, the electron transport layer material contains the following structural fragments: at least one of a pyridine structure, a pyrimidine structure, a triazine structure, a benzimidazole structure, a benzoxazole structure, a benzothiazole structure, an N-naphthalene structure, an N-heterophthalene structure, an N-heterocarbazole structure, an N-heterodibenzofuran structure, and an N-heterodibenzothiophene structure.

[0142] In the present invention, there is no particular limitation on the electron transport layer materials, which exemplarily include but are not limited to:

[0143]

[0144]

[0145]

[0146] In the present invention, the cathode material is a metal with a 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 (e.g., an alloy composed of an alkali metal or alkaline earth metal and silver, e.g., 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 functions, such as Ag or Al, may also be used. In this case, combinations of these metals are typically used, such as Ca / Ag, Mg / Ag, or Ba / Ag.

[0147] Alternatively, a thin intermediate layer of a material with a high dielectric constant may be introduced between the metal cathode and the organic semiconductor to form a multilayer structure. The material with a high dielectric constant may also be referred to as an electron injection material, and may be fluorides of alkali metals or alkaline earth metals, and corresponding oxides or carbonates (e.g., LiF, Li2O, BaF2, MgO, NaF, CsF, Cs2CO3, etc.) or lithium quinoline (LiQ).

[0148] Compared with the prior art, the present invention has the following beneficial effects:

[0149] In the present invention, the structure of the carbazole compound is designed to make it suitable as the main material of the light-emitting layer of the organic electroluminescent device, so that the organic electroluminescent device has higher current efficiency and longer service life. DETAILED DESCRIPTION

[0150] For the convenience of understanding the present invention, the present invention is given below with examples. It should be understood by those skilled in the art that the examples are only for the purpose of helping to understand the present invention and should not be regarded as specific limitations of the present invention.

[0151] Synthesis Example 1

[0152] This synthesis example provides a carbazole compound P1, the synthesis method of which is as follows:

[0153]

[0154] (1) Synthesis of intermediate P1-2

[0155] In a nitrogen atmosphere, 17 g of compound P1-1 and 300 mL of tetrahydrofuran were added to a three-necked flask, and then the temperature was lowered to -78 ° C. A 0.05 mol n-hexane solution of butyl lithium (concentration 1.6 M, 31 mL) was slowly added, and then the temperature was maintained at -78 ° C to -60 ° C for 30 min. A solution prepared by 15.2 g of triphenylsilyl chloride and 150 mL of tetrahydrofuran, 0.0003 mol Pd(dba)2, and 0.0003 mol of anhydrous nickel chloride were added. The temperature was slowly raised to room temperature for 2 hours, and then raised to reflux for 2 hours. The temperature was lowered, and water and toluene were added for separation. The organic layer was washed with water until neutral, dried over anhydrous magnesium sulfate, filtered to remove the desiccant, concentrated to dryness, and separated by silica gel column chromatography and eluted with petroleum ether to obtain intermediate P1-2 (18.2 g).

[0156] The obtained intermediate P1-2 was detected by mass spectrometry, and the m / z was 536.14.

[0157] (2) Synthesis of compound P1

[0158] In a nitrogen atmosphere, dry xylene (150 mL), intermediate P1-1 (5.5 g), carbazole (1.9 g), Pd(dba)2 (bis(dibenzylideneacetonepalladium, 0.1 g), 10% tri-tert-butylphosphine toluene solution (the mass of tri-tert-butylphosphine solution is 0.8 g) and sodium tert-butoxide (1.2 g) were added to a 250 mL three-necked flask, heated to reflux for 8 h, cooled to room temperature, and separated by adding water. The organic layer was then washed with water until neutral, dried over magnesium sulfate, filtered to remove magnesium sulfate, concentrated to dryness, and separated by silica gel column chromatography with petroleum ether: ethyl acetate = 20:1 (volume ratio) to obtain carbazole compound P1 (4.7 g).

[0159] The carbazole compound P1 was subjected to mass spectrometry detection: the mass-to-charge ratio (m / z) was measured to be 667.23.

[0160] Synthesis Examples 2-7

[0161] Referring to the synthesis method of the carbazole compound P1 provided in Synthesis Example 1, the corresponding carbazole compound was reacted with P1-2 to prepare the following carbazole compounds, and the obtained compounds were respectively detected by mass spectrometry, as shown in Table 1 below.

[0162] Table 1

[0163]

[0164]

[0165] Synthesis Example 8

[0166] This synthesis example provides a carbazole compound P25, the synthesis method of which is as follows:

[0167]

[0168] Referring to the synthesis method of the intermediate P1-2 provided in Synthesis Example 1, the compound P1-1 was replaced with an equal amount of compound P25-1 to obtain the carbazole compound P25.

[0169] The carbazole compound P25 was subjected to mass spectrometry detection: the mass-to-charge ratio (m / z) was measured to be 849.29.

[0170] Synthesis Example 9

[0171] This synthesis example provides a carbazole compound P26, the synthesis method of which is as follows:

[0172]

[0173] The synthesis method of the intermediate P1-2 provided in Synthesis Example 1 was referred to, except that the compound P1-1 was replaced with an equal amount of compound P26-1 to obtain the carbazole compound P26.

[0174] The carbazole compound P26 was subjected to mass spectrometry detection: the mass-to-charge ratio (m / z) was measured to be 1014.35.

[0175] Synthesis Example 10

[0176] This synthesis example provides a carbazole compound P37, the synthesis method of which is as follows:

[0177]

[0178] (1) Synthesis of intermediate P37-2

[0179] Under a nitrogen atmosphere, 100 mL of dioxane was added to a 500 mL three-necked flask, followed by 4.0 g of 4-triphenylsilylphenylboronic acid, 3.6 g of intermediate P1-1, 2.12 g (0.02 mol) of sodium carbonate, and 0.23 g (0.0002 mol) of tetrakistriphenylphosphine palladium. The temperature was slowly raised to reflux for 4 hours, then cooled to room temperature, and water and ethyl acetate were added for separation. The organic layer was washed with water, dried over magnesium sulfate, and after removing the desiccant, concentrated to dryness, and separated by silica gel column chromatography and eluted with petroleum ether to obtain 5.1 g of intermediate P37-2.

[0180] The obtained intermediate P37-2 was subjected to mass spectrometry detection, and the mass-to-charge ratio (m / z) was measured to be 612.17.

[0181] (2) Synthesis of compound P37

[0182] Referring to the synthesis method of compound P1 provided in Synthesis Example 1, carbazole and P37-2 were reacted to prepare the carbazole compound P37.

[0183] The carbazole compound P37 was subjected to mass spectrometry detection: the mass-to-charge ratio (m / z) was measured to be 743.26.

[0184] Other compounds for which the specific synthesis methods are not listed can be synthesized by referring to the above examples in combination with common knowledge in the art.

[0185] The specific structures of some of the compounds used in the following application examples and comparative application examples are as follows:

[0186]

[0187]

[0188] Application Example 1

[0189] This application example provides a blue organic electroluminescent device, using the compound provided by the present invention as the main material of the light-emitting layer. The structure of the blue organic electroluminescent device is:

[0190] ITO / HT-1: HI-2[5%](80nm) / HT-1(30nm) / EB-1(20nm) / host material: PBD-1[5%](35nm) / ETL-1(25nm) / LiF(0.5nm) / Al(150nm).

[0191] The preparation method of the blue organic electroluminescent device is as follows:

[0192] The material was placed in a vacuum chamber and evacuated to 1×10 -5 ~1×10 -6 Pa was vacuum evaporated onto the cleaned ITO substrate to prepare OLED devices.

[0193] PBD-1 [5%] refers to the dye doping ratio, meaning 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, meaning the volume ratio of the hole-transporting material HT-1 to the p-type dopant HI-2 is 95:5. HT-1 is a hole-transporting material; HT-1:HI-2 [5%] serves as the hole-injection layer, and EB-1 is the electron-blocking layer.

[0194] The main material of the light-emitting layer of the blue organic electroluminescent device provided in this application example is compound P1.

[0195] Application Example 2-12, Comparative Application Example 1-4

[0196] Application Examples 2-12 and Comparative Application Examples 1-4 respectively provide a blue light organic electroluminescent device. The only difference from Application Example 1 is that the main material compound P1 of the light-emitting layer is replaced by other compounds (see Table 2 below for details). The other preparation steps and conditions are the same as those of Application Example 1.

[0197] Performance Testing

[0198] The brightness, driving voltage, current efficiency and LT95 of the organic electroluminescent device provided above were tested, wherein the current efficiency is the brightness of 1000cd / m 2 The corresponding value, LT95, refers to maintaining the initial current density of the device at 10mA / cm 2 The time required for the device efficiency to drop to 95% of the efficiency corresponding to the initial current density is constant, where current efficiency and LT95 are relative values. The specific test results are shown in Table 2 below:

[0199] Table 2

[0200]

[0201]

[0202] According to Application Examples 10 and 11, when Ar4 in the compound of Formula I is a triphenylsilyl group, the device prepared using the compound as the main material of the organic electroluminescent device has a better lifespan.

[0203] As can be seen from the above, the structure of the carbazole compound is designed in the present invention to make it suitable as the host material of the light-emitting layer of the organic electroluminescent device, so that the organic electroluminescent device has higher current efficiency and longer service life.

[0204] Application Examples 13-15, Comparative Application Example 5

[0205] Application Examples 13-15 and Comparative Application Example 5 respectively provide an organic electroluminescent device, which differs from Application Example 1 only in that the main material compound P1 of the light-emitting layer is replaced by other compounds, and the dye PBD-1 is replaced by compound PBD-2 (see Table 3 below for details). The other preparation steps and conditions are the same as those in Application Example 1.

[0206] The performance test method is the same as above. The specific test results are shown in Table 3 below:

[0207] Table 3

[0208] Main material dye <![CDATA[Brightness / (cd / m 2 )]]> Current efficiency LT95 Application Example 13 P40 PBD-2 1000 1 1 Application Example 14 P45 PBD-2 1000 1.06 0.98 Application Example 15 P37 PBD-2 1000 1.27 0.81 Comparative Application Example 5 D4 PBD-2 1000 0.88 0.57

[0209] As can be seen from the above, the structure of the carbazole compound is designed in the present invention to make it suitable as the host material of the light-emitting layer of the organic electroluminescent device, so that the organic electroluminescent device has higher current efficiency and longer service life.

[0210] The applicant declares that the present invention uses the above-described embodiments to illustrate the detailed process flow of the present invention, but the present invention is not limited to the above-described detailed process flow, that is, it does not mean that the present invention must rely on the above-described detailed process flow to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent replacements for various raw materials in the products of the present invention, addition of auxiliary ingredients, and selection of specific methods, etc., are all within the scope of protection and disclosure of the present invention.

Claims

1. A carbazole compound, characterized in that The carbazole compound includes a compound having a structure shown in the following formula I: Ar1 to Ar3 are each independently selected from any one of C6-C40 aryl, C6-C30 heteroaryl or C1-C12 alkyl; Ar4 is selected from any one of C6-C40 aryl, C6-C30 heteroaryl, C1-C12 alkyl or triphenylsilyl; Ar is selected from any one of a single bond, a C6-C40 arylene group, or a C6-C30 heteroarylene group; R1 to R2 are each independently selected from any one of -H, C6-C40 aryl, C6-C30 heteroaryl or C1-C12 alkyl; X is selected from C or Si; Z is selected from O and S; The hydrogen atoms in the compound of formula I may each independently be substituted by at least one of a deuterium atom, -F, -CN, a C6-C20 aryl group, a C1-C12 alkyl group, or a C1-C12 alkoxy group.

2. The carbazole compound according to claim 1, characterized in that The C6-C40 aryl group is selected from any one or a combination of at least two of phenyl, biphenyl, terphenyl, naphthyl, anthracenyl, phenanthrenyl, fluorenyl, benzofluorenyl, dibenzofluorenyl, naphthiofluorenyl, pyrenyl, peryl, spirofluorenyl, triphenylene, fluoranthenyl, hydrogenated benzanthryl, indenofluorenyl, benzoindenofluorenyl, dibenzoindenofluorenyl, naphthiofluorenyl or benzonaphthofluorenyl; Preferably, the C6-C40 arylene group is selected from any one of phenylene, biphenylene, terphenylene, naphthylene, anthrylene, phenanthrylene, fluorenylene, benzofluorenylene, dibenzofluorenylene, naphthofluorenylene, pyrenylene, perylene, spirofluorenylene, triphenylene, fluoranthenylene, hydrogenated benzanthrylene, indenofluorenylene, benzoindenofluorenylene, dibenzoindenofluorenylene, naphthofluorenylene or benzonaphthofluorenylene, or a combination of at least two thereof; Preferably, the C6-C30 heteroaryl group is selected from any one of dibenzofuranyl, dibenzothiophenyl, naphthobenzofuranyl, naphthobenzothiophenyl, dinaphthofuranyl, dinaphthothiophenyl, carbazolyl, phenylcarbazolyl, and carbazolylphenyl; Preferably, the C6-C30 heteroarylene group is selected from any one of dibenzofuranylene, dibenzothiophenylene, naphthobenzofuranylene, naphthobenzothiophenylene, dinaphthofuranylene, dinaphthothiophenylene, carbazolylene, phenylcarbazolylene, and carbazolylenephenyl; Preferably, the C6-C20 aryl group is selected from any one of phenyl, biphenyl, terphenyl, naphthyl, anthracenyl, phenanthrenyl, fluorenyl, triphenylene, and fluoranthenyl; Preferably, the C1-C12 alkyl group is selected from any one of methyl, ethyl, propyl, butyl, pentyl or hexyl; Preferably, the C1-C12 alkoxy group is selected from any one of methoxy, ethoxy, propoxy, butoxy, pentyloxy or hexyloxy.

3. The carbazole compound according to claim 1 or 2, characterized in that Ar1 to Ar3 are each independently selected from any one of phenyl, biphenyl, naphthyl, dibenzofuranyl, and carbazolyl; Preferably, Ar4 is selected from any one of phenyl, biphenyl, naphthyl, dibenzofuranyl, carbazolyl, and triphenylsilyl, and more preferably any one of phenyl, naphthyl, and triphenylsilyl; Preferably, Ar is selected from any one of a single bond, a phenylene group, a naphthylene group, a biphenylene group, a triphenylene group, a fluoranthenylene group, a carbazolylene group, a phenylene carbazolylene group, a carbazolylene phenyl group, a dibenzofuranyl group, and a dibenzothiophenyl group, and is more preferably any one of a single bond, a phenylene group, a biphenylene group, a dibenzofuranyl group, and a carbazolylene group; Preferably, R1 and R2 are each independently selected from any one of -H, methyl, ethyl, propyl, tert-butyl, phenyl, biphenyl, naphthyl, triphenylene, dibenzofuranyl, dibenzothiophenyl, carbazolyl, and carbazolyl, or a combination of at least two thereof, and are further preferably any one of -H, methyl, tert-butyl, phenyl, naphthyl, biphenyl, triphenylene, carbazolyl, dibenzothiophenyl, and dibenzofuranyl; Preferably, R2 is selected from H, and R1 is selected from any one of -H, methyl, tert-butyl, phenyl, naphthyl, biphenyl, triphenylene, carbazolyl, dibenzothiophenyl, and dibenzofuranyl; Preferably, Ar4 is selected from triphenylsilyl.

4. The carbazole compound according to any one of claims 1 to 3, characterized in that The hydrogen atoms in the compound of formula I may each independently be substituted by at least one of -D, -F, -CN, phenyl, naphthyl, biphenyl, carbazolyl, phenylcarbazolyl, carbazolylphenyl, methyl, ethyl, propyl, butyl, methoxy, ethoxy, propoxy or butoxy; Preferably, the hydrogen atoms in the compound of formula I can each independently be substituted by at least one of -D, -F, -CN, methyl, tert-butyl, methoxy, propoxy, naphthyl, phenyl, carbazolyl, phenylcarbazolyl, and carbazolylphenyl.

5. The carbazole compound according to any one of claims 1 to 4, characterized in that The compound of formula I includes any one of the following substituted or unsubstituted compounds: The substitution means that the hydrogen atoms in the compound of formula I can each independently be replaced by a deuterium atom; Preferably, the compound of formula I further comprises Replace with The dotted line indicates the connection site; Preferably, the compound of formula I also includes compounds in which the Si atom in the above compound is replaced by a C atom.

6. The carbazole compound according to any one of claims 1 to 5, characterized in that The compound of formula I is selected from any one of the following compounds:

7. An intermediate, characterized in that The intermediates include the following compounds: Wherein, Ar1 to Ar3, Ar4, R1, R2, X, and Z have the same definitions as in claim 1; X1 and X2 are each independently selected from any one of F, chlorine, bromine or iodine; The intermediate is used to prepare the carbazole compound according to any one of claims 1 to 6; Preferably, the intermediate includes the following compounds:

8. An organic electroluminescent device, characterized in that The organic electroluminescent device comprises an anode, a cathode and an organic thin film layer arranged between the anode and the cathode; The organic thin film layer comprises the carbazole compound according to any one of claims 1 to 6.

9. The organic electroluminescent device according to claim 8, characterized in that: The organic thin film layer includes a light-emitting layer, and a main material of the light-emitting layer includes the carbazole compound according to any one of claims 1 to 6.

10. The organic electroluminescent device according to claim 8 or 9, characterized in that: The organic electroluminescent device is a blue organic electroluminescent device.

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