Carbazole compound and organic electroluminescent device

Abstract

The invention provides a carbazole compound and an organic electroluminescent device. The carbazole compound has a structure as shown in a formula I. Through the design of the carbazole compound, the carbazole compound with excellent performance is prepared, and the organic electroluminescent device prepared by taking the carbazole compound as a material of the electron blocking layer has relatively 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 a carbazole compound to produce a carbazole compound with excellent performance. The organic electroluminescent device produced using the carbazole compound as the material for the electron blocking layer exhibits high current efficiency and a long lifespan.

[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 having a structure shown in the following formula I:

[0007]

[0008] wherein R1 and R2 each independently represent any one of H, a C1-C10 alkyl group or a C6-C20 aryl group, and at least one of R1 and R2 represents a C1-C10 alkyl group or a C6-C20 aryl group;

[0009] R3 represents any one of H, C1-C10 alkyl or C6-C20 aryl;

[0010] Ring A and Ring B each independently represent a benzene ring or a naphthalene ring;

[0011] Ar 601represents a C6-C20 arylene group;

[0012] n represents 0 or 1, m represents 0 or 1;

[0013] Dashed lines indicate single bonds or their absence;

[0014] The hydrogen atoms in the compounds of formula I shown may each independently be replaced by a deuterium atom (D).

[0015] The present invention prepares a carbazole compound with excellent performance by designing a carbazole compound. At least one of R1 and R2 is limited to a C1-C10 alkyl group or a C6-C12 aryl group to increase the rigidity of the molecule. The compound has relatively suitable HOMO and LUMO energy levels, good molecular film-forming properties, and strong charge transport capabilities. The organic electroluminescent device prepared by using the carbazole compound as the material for the electron blocking layer has high current efficiency and long life.

[0016] It should be noted that when n represents 1 and m represents 0, Ar 601 It represents a C6-C20 aryl group.

[0017] In the present invention, C1-C10 can be C1, C2, C3, C4, C5, C6, C7, C8, C9 or C10.

[0018] C6-C20 can be C6, C8, C10, C12, C15, C18 or C20, etc.

[0019] In the present invention, "D" represents a deuterium atom, and the same shall apply hereinafter.

[0020] 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.

[0021] Preferably, the carbazole compound has the structure shown in the following formula IA, formula IB, formula IC, and formula ID:

[0022]

[0023] Among them, R1, R2, R3, Ring A, Ring B, Ar 601 , n, and m have the same definitions as above.

[0024] As a preferred technical solution of the present invention, R1 and R2 each independently represent any one of H, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, decyl, phenyl, naphthyl, and biphenyl, and are further preferably any one of H, methyl, isopropyl, tert-butyl, methylcyclopentyl, methylcyclohexyl, adamantyl, bicyclo[2,2,1]heptyl, bicyclo[2,2,2]octyl, phenyl, naphthyl, and biphenyl.

[0025] As a preferred technical solution of the present invention, R3 represents any one of H, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, decyl, phenyl, naphthyl, and biphenyl, and is further preferably any one of H, methyl, isopropyl, tert-butyl, methylcyclopentyl, methylcyclohexyl, adamantyl, bicyclo[2,2,1]heptyl, bicyclo[2,2,2]octyl, phenyl, naphthyl, and biphenyl, and is further preferably any one of H, methyl, tert-butyl, or phenyl.

[0026] As a preferred technical solution of the present invention, the Ar 601 represents any one of phenylene, naphthylene, and biphenylene.

[0027] It should be noted that if m is 0, then Ar 601 represents any one of phenyl, naphthyl or biphenyl

[0028] As a preferred technical solution of the present invention, the ring A and the ring B both represent benzene rings.

[0029] As a preferred technical solution of the present invention, one of the ring A and the ring B is a benzene ring, and the other is a naphthalene ring.

[0030] As a preferred technical solution of the present invention, m represents 1 and n represents 0.

[0031] As a preferred technical solution of the present invention, m represents 1, and n represents 1.

[0032] As a preferred technical solution of the present invention, m represents 0 and n represents 1.

[0033] As a preferred technical solution of the present invention, m represents 0 and n represents 0.

[0034] As a preferred technical solution of the present invention, the compound of formula I is selected from any one of the following substituted or unsubstituted compounds P1 to P51:

[0035]

[0036]

[0037]

[0038]

[0039] The substitution means that the hydrogen atoms in Compounds P1 to P51 may each independently be substituted with a deuterium atom.

[0040] Preferably, the compound of formula I is selected from any one of the following compounds:

[0041]

[0042]

[0043] In the present invention, there is no particular limitation on the preparation method of the compound of formula I, and any commonly used preparation method in the art is applicable, as exemplified below:

[0044] When m=1 and n=0, the compound of formula I has the structure shown in the following formula I-1:

[0045]

[0046] A method for synthesizing compound I-1 is:

[0047]

[0048] wherein R1, R2, R3, Ring A, and Ring B have the same definitions as above;

[0049] Dashed lines indicate single bonds or their absence;

[0050] X, Y, and Z each independently represent a halogen atom (for example, F, Cl, Br, or I).

[0051] The specific reaction steps are as follows:

[0052] (1) M1-1-1 and M1-1-2 react to form M1-1-3;

[0053] (2) M1-1-3 undergoes halogenation reaction to generate I-1-0;

[0054] (3) The compound shown in I-1-0 is first reacted with butyl lithium, and then with Reaction to generate the intermediate shown in I-1-a;

[0055] (4) The intermediate shown in I-1-a first reacts with butyl lithium and then with Reaction to produce the compound shown in 1-1.

[0056] Of course, in the above synthesis method, the butyl lithium in step (3) can be replaced with other alkyl lithium salts, or dialkyl lithium amide (such as lithium diisopropylamide), and the compound shown in formula I-1 can also be prepared.

[0057] It should also be noted that the present invention does not have any special restrictions on the specific process conditions in steps (1) to (4), and can be designed according to the preparation methods in the art.

[0058] When m=0, n=0, the compound of formula I has the structure shown in the following formula I-2:

[0059]

[0060] A method for synthesizing compound I-2 is:

[0061]

[0062] The specific reaction steps are as follows:

[0063] (1) M1-1-3 undergoes halogenation reaction to generate I-2-0;

[0064] (2) The compound shown in I-2-0 is first reacted with butyl lithium, and then with Reaction to produce the compound shown in I-2.

[0065] Of course, in the above synthesis method, the butyl lithium in step (2) can be replaced with other alkyl lithium salts, or dialkyl lithium amide (such as lithium diisopropylamide), and the compound shown in formula I-2 can also be prepared.

[0066] It should also be noted that the present invention does not have any special restrictions on the specific process conditions in step (1) to step (2), and can be designed according to the preparation method in the art.

[0067] In a second aspect, the present invention further provides an intermediate, comprising the following compound:

[0068]

[0069] Wherein, R1, R2, R3, Ring A, and Ring B have the same definitions as above;

[0070] Dashed lines indicate single bonds or their absence;

[0071] X and Y each independently represent a halogen atom;

[0072] The intermediates do not include the following compounds:

[0073]

[0074] The intermediate is used to prepare the carbazole compound as described in the first aspect.

[0075] Preferably, the intermediate includes the following compounds:

[0076]

[0077] 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;

[0078] The organic thin film layer includes the carbazole compound described in the first aspect.

[0079] As a preferred technical solution of the present invention, the organic thin film layer includes a hole layer, and the hole layer includes a hole injection layer, a hole transport layer and an electron blocking layer.

[0080] Preferably, the organic thin film layer includes an electron blocking layer and a light-emitting layer, and the material of the electron blocking layer includes the carbazole compound as described in the first aspect.

[0081] Preferably, the light-emitting layer is a phosphorescent light-emitting layer.

[0082] As a preferred technical solution of the present invention, the organic electroluminescent device is a blue organic electroluminescent device.

[0083] In the present invention, the light-emitting layer includes a main material of the light-emitting layer and a doping material, wherein the doping material is also called a dye or a phosphorescent material, and the main material of the light-emitting layer can be a single compound or a mixture of two or more compounds.

[0084] 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.

[0085] 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%.

[0086] 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. In the present invention, the specific choice of phosphorescent material is not particularly limited, and all commonly used doping materials for light-emitting layers in the art are applicable, including but not limited to compounds having a structure as shown in Formula PD:

[0087]

[0088] wherein M is selected from any one of Ir, Pt, Pd, Os, Ti, Zr, Hf, Eu, Tb, Tm, Cu, or Au;

[0089] Y1-Y4 are each independently selected from carbon or nitrogen;

[0090] 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;

[0091] 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;

[0092] 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;

[0093] 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.

[0094] a1 and a2 are each independently an integer selected from 1 to 5, for example, 1, 2, 3, 4 or 5;

[0095] b is an integer selected from 0-4, for example, 0, 1, 2, 3 or 4;

[0096] a is selected from 1, 2 or 3;

[0097] L1 is a monovalent organic ligand, a divalent organic ligand or a trivalent organic ligand.

[0098] Preferably, the compound of formula PD is selected from any one of the following compounds:

[0099]

[0100]

[0101]

[0102]

[0103]

[0104]

[0105] In the present invention, the hole layer material (including the hole injection layer, the hole transport layer and the electron blocking layer) may also have a structure as shown in the following formula HT-GH4:

[0106]

[0107] 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;

[0108] Ar 41 、Ar 42 each 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;

[0109] 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.

[0110] Preferably, the compound of formula HT-GH4 is selected from any one of the following compounds:

[0111]

[0112]

[0113]

[0114]

[0115]

[0116] 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.

[0117] 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 limitation 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-phenanthrene structure, an N-carbazole structure, an N-dibenzofuran structure, and an N-dibenzothiophene structure.

[0118] In the present invention, there is no particular limitation on the electron transport layer material, and examples thereof include but are not limited to the following structures:

[0119]

[0120] 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.

[0121] 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).

[0122] Compared with the prior art, the present invention has the following beneficial effects:

[0123] The invention designs the structure of the carbazole compound so that it is suitable for use as an electron blocking layer material of an organic electroluminescent device. The organic electroluminescent device prepared thereby has high current efficiency and long service life. DETAILED DESCRIPTION

[0124] 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.

[0125] Synthesis Example 1 Synthesis of Compound P3

[0126] This synthesis example provides compound P3 and its synthesis method, which is as follows:

[0127]

[0128] (1) Synthesis of intermediate P3-0

[0129] Under nitrogen protection, dry toluene (80 mL), 2-(2-naphthyl)bromobenzene (3.0 g), carbazole (1.7 g), Pd(dba)2 (bis(dibenzylideneacetonepalladium, 0.0575 g), 10% tri-tert-butylphosphine toluene solution (the mass of tri-tert-butylphosphine solution is 0.4 g) and sodium tert-butoxide (1.44 g) were added to a 250 mL three-necked flask. The reaction was 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 with magnesium sulfate, filtered to remove the magnesium sulfate, concentrated to dryness, and crystallized from ethanol to obtain intermediate P3-0 (2.1 g).

[0130] The intermediate P3-0 was subjected to mass spectrometry detection: the mass-to-charge ratio (m / z) was measured to be 369.15.

[0131] (2) Synthesis of intermediate P3-1

[0132] Under nitrogen protection, 3.7 g of intermediate P3-0 and 50 mL of DMF were added to a 500 mL three-necked flask, and 3.7 g of solid NBS (N-bromosuccinimide) was added in batches at 20-25 ° C. After the addition, the reaction was stirred at 20-25 ° C for 8 h. Water was added, and the solid was filtered. After drying, it was crystallized with ethanol to obtain 4.6 g of intermediate P3-1.

[0133] The intermediate P3-1 was subjected to mass spectrometry detection: the peak with the largest mass-to-charge ratio (m / z) was 526.97, with an abundance of 100%, and the other m / z were 524.97 and 528.97, with an abundance of about 50%.

[0134] (3) Synthesis of compound P3

[0135] Under nitrogen protection, 0.01 mol of the P3-1 intermediate and 120 mL of tetrahydrofuran were added to a 500 mL three-necked flask, and then the temperature was lowered to -78 ° C. A n-hexane solution containing 0.022 mol of butyl lithium (concentration 1.6 M, 13.8 ml) was slowly added, and then the temperature was kept at -78 ° C to -60 ° C for 30 min. A solution prepared by 0.022 mol of triphenylsilyl chloride and 30 mL of tetrahydrofuran, 0.0002 mol of Pd (dba) 2, and 0.0002 mol of anhydrous nickel chloride were added. The temperature was slowly raised to room temperature for 2 hours, then raised to reflux temperature, reacted for 2 hours, cooled, and separated by adding water and toluene. 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 with petroleum ether: ethyl acetate = 20:1 (volume ratio) to give compound P3 (6.9 g).

[0136] The obtained compound P3 was subjected to mass spectrometry detection, and the mass-to-charge ratio (m / z) was measured to be 885.32.

[0137] Synthesis Example 2 Synthesis of Compound P20

[0138] This synthesis example provides compound P20 and its synthesis method, which is as follows:

[0139]

[0140] (1) Synthesis of intermediate P20-0

[0141] Referring to the synthesis method of intermediate P3-0 provided in Example 1, 2-(2-naphthyl)bromobenzene was replaced with an amount of the same substance as The intermediate P20-0 was obtained.

[0142] The intermediate P20-0 was subjected to mass spectrometry detection: the mass-to-charge ratio (m / z) was measured to be 355.23.

[0143] (2) Synthesis of intermediate P20-1

[0144] Referring to the synthesis method of intermediate P3-1 provided in Example 1, the amount of NBS (N-bromosuccinimide) was reduced to 1.7 g to obtain intermediate P20-1.

[0145] The intermediate P20-1 was subjected to mass spectrometry detection: the two peaks with the largest mass-to-charge ratios (m / z) were measured to be 433.14 and 435.14, with basically the same abundance.

[0146] (3) Synthesis of compound P20

[0147] Under nitrogen protection, 0.01 mol of the P20-1 intermediate and 100 mL of tetrahydrofuran were added to a 500 mL three-necked flask, and then the temperature was lowered to -78 ° C. A n-hexane solution containing 0.011 mol of butyl lithium (concentration 1.6 M, 6.9 mL) was slowly added, and then maintained at -78 ° C to -60 ° C for 30 min. A solution prepared by 0.011 mol of triphenylsilyl chloride and 20 mL of tetrahydrofuran, 0.0001 mol of Pd(dba)2, and 0.0001 mol of anhydrous nickel chloride were added. The temperature was slowly raised to room temperature and reacted for 2 h, then raised to reflux temperature and reacted for 2 h. 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 with petroleum ether: ethyl acetate = 20:1 (volume ratio) to obtain compound P20 (4.7 g).

[0148] The obtained compound P20 was subjected to mass spectrometry detection, and the mass-to-charge ratio (m / z) was measured to be 613.32.

[0149] Synthesis Example 3 Synthesis of Compound P26

[0150] This synthesis example provides compound P26 and its synthesis method, which is as follows:

[0151]

[0152] (1) Synthesis of intermediate P26-1

[0153] Referring to the synthesis method of intermediate P3-1 provided in Example 1, intermediate P26-1 was obtained.

[0154] The intermediate P26-1 was subjected to mass spectrometry detection: the peak with the largest mass-to-charge ratio (m / z) was 513.05, with an abundance of 100%, and the other m / z were 511.05 and 515.05, with an abundance of about 50%.

[0155] (2) Synthesis of intermediate P26-2

[0156] Referring to the synthesis method of compound P20 provided in Example 2, intermediate P26-2 was obtained.

[0157] The intermediate P26-2 was subjected to mass spectrometry detection: the two peaks with the largest mass-to-charge ratios (m / z) were measured to be 693.22 and 691.23, with basically the same abundance.

[0158] (3) Synthesis of compound P26

[0159] Under nitrogen protection, 100 mL of toluene, 40 mL of ethanol, and 20 mL of water were added to a 500 mL three-necked flask in sequence, followed by 0.01 mol of intermediate P26-2, 0.01 mol of triphenylsilylphenylboronic acid, 0.02 mol of sodium carbonate, and 0.0002 mol of tetrakistriphenylphosphine palladium. The temperature was slowly raised to reflux temperature, reacted for 8 hours, cooled to room temperature, and split with water. The organic layer was washed with water and dried over magnesium sulfate. After removing the desiccant, the mixture was concentrated to dryness and separated by silica gel column chromatography with petroleum ether:ethyl acetate = 10:0.5 (volume ratio) to give compound P26 (6.0 g).

[0160] The obtained compound P26 was subjected to mass spectrometry detection, and the mass-to-charge ratio (m / z) was measured to be 947.43.

[0161] Synthesis Examples 4-9

[0162] Synthesis Examples 4-9 respectively provide a compound (see Table 1 below for details). The synthesis method of the compound refers to the synthesis method of compound P3 provided in step (3) of Synthesis Example 1, with the only difference being that P3-1 is replaced with other corresponding brominated compounds. The obtained compound is subjected to mass spectrometry detection, and its mass-to-charge ratio data are shown in Table 1 below.

[0163] Table 1

[0164]

[0165]

[0166] Synthesis Example 10 Synthesis of Compound P49

[0167] This synthesis example provides compound P49 and its synthesis method, which is as follows:

[0168]

[0169] Referring to the synthesis method of compound P20 provided in Synthesis Example 2, compound P49 was obtained.

[0170] The obtained compound P49 was subjected to mass spectrometry detection, and the mass-to-charge ratio (m / z) was measured to be 577.22.

[0171] Synthesis Example 11 Synthesis of Compound P49D

[0172] This synthesis example provides compound P4D9 and its synthesis method, which is as follows:

[0173]

[0174] Referring to the synthesis method of compound P20 provided in Synthesis Example 2, compound P49D was obtained.

[0175] The obtained compound P49D was subjected to mass spectrometry detection, and the mass-to-charge ratio (m / z) was measured to be 584.27.

[0176] Synthesis Example 12 Synthesis of Compound P50

[0177] This synthesis example provides compound P50 and its synthesis method, which is as follows:

[0178]

[0179] Referring to the synthesis method of compound P26 provided in Synthesis Example 3, compound P50 was obtained.

[0180] The obtained compound P50 was subjected to mass spectrometry detection, and the mass-to-charge ratio (m / z) was measured to be 653.25.

[0181] Synthesis Example 13 Synthesis of Compound P50D

[0182] This synthesis example provides compound P50D and its synthesis method, which is as follows:

[0183]

[0184] Referring to the synthesis method of compound P26 provided in Synthesis Example 3, compound P50D was obtained.

[0185] The obtained compound P50D was subjected to mass spectrometry detection, and the mass-to-charge ratio (m / z) was measured to be 660.30.

[0186] Synthesis Example 14 Synthesis of Compound P16

[0187] This synthesis example provides compound P16 and its synthesis method, which is as follows:

[0188]

[0189] (1) Synthesis of intermediate P16-1

[0190] Under nitrogen protection, 0.01 mol 3,6-dibromo-9-(2-(tert-butyl)phenyl)-9H-carbazole and 100 mL tetrahydrofuran were added to a 500 mL three-necked flask, and then the temperature was lowered to -78 ° C. A n-hexane solution containing 0.011 mol butyl lithium (concentration 1.6 M, 6.9 mL) was slowly added, and then the temperature was kept at -78 ° C to -60 ° C for 30 min, and 0.011 mol A solution prepared with 20 mL of tetrahydrofuran, 0.0001 mol of Pd(dba)2, and 0.0001 mol of anhydrous nickel chloride was slowly heated to room temperature for 2 h, then heated to reflux temperature for 2 h, cooled, and separated by adding water and toluene. The organic layer was washed with water until neutral, dried over anhydrous magnesium sulfate, filtered to remove the desiccant, and concentrated to dryness. The mixture was separated by silica gel column chromatography with petroleum ether:ethyl acetate = 20:1 (volume ratio) to obtain intermediate P16-1 (4.9 g).

[0191] The obtained intermediate P16-1 was subjected to mass spectrometry detection, and the two peaks with the largest mass-to-charge ratios (m / z) were measured to be 635.15 and 633.15, with basically the same abundance.

[0192] (2) Synthesis of compound P16

[0193] Referring to the synthesis of compound P20 provided in Synthesis Example 2, compound P16 was obtained.

[0194] The obtained compound P16 was subjected to mass spectrometry detection, and the mass-to-charge ratio (m / z) was measured to be 813.32.

[0195] Synthesis Example 15 Synthesis of Compound P17

[0196] This synthesis example provides compound P17 and its synthesis method, which is as follows:

[0197]

[0198] Referring to the synthesis method of compound P3 provided in Synthesis Example 1, compound P17 was obtained.

[0199] The obtained compound P17 was subjected to mass spectrometry detection, and the mass-to-charge ratio (m / z) was measured to be 811.31.

[0200] Preparation Example 1 Synthesis of Intermediate P2-1

[0201]

[0202] Referring to the synthesis method of intermediate P3-1 provided in Example 1, intermediate P2-1 was obtained.

[0203] The intermediate P2-1 was subjected to mass spectrometry detection: the peak with the largest mass-to-charge ratio (m / z) was 552.99, with an abundance of 100%, and the other m / z were 550.99 and 554.98, with an abundance of about 50%.

[0204] Preparation Example 2 Synthesis of Intermediate P7-1

[0205]

[0206] Referring to the synthesis method of intermediate P3-1 provided in Example 1, intermediate P7-1 was obtained.

[0207] The intermediate P7-1 was subjected to mass spectrometry detection: the peak with the largest mass-to-charge ratio (m / z) was 567.00, with an abundance of 100%, and the other m / z: 565.00 and 569.00, with an abundance of about 50%.

[0208] Preparation Example 3 Synthesis of Intermediate P9-1

[0209]

[0210] Referring to the synthesis method of intermediate P3-1 provided in Example 1, intermediate P9-1 was obtained.

[0211] The intermediate P9-1 was subjected to mass spectrometry detection: the peak with the largest mass-to-charge ratio (m / z) was 533.02, with an abundance of 100%, and the other m / z were 535.02 and 531.02, with an abundance of about 50%.

[0212] Compounds not listed above can be synthesized by referring to the above methods in combination with common knowledge in the art.

[0213] The specific structures of some of the compounds used in the following application examples and comparative application examples are as follows

[0214]

[0215]

[0216] Application Example 1

[0217] This application example provides a blue organic electroluminescent device, using the compound P1 provided by the present invention as an electron blocking layer material. The structure of the blue organic electroluminescent device is:

[0218] ITO / HT-1: HI-2[5%](80nm) / HT-1(30nm) / P1(20nm) / H1: PBD-1[5%](35nm) / ETL-1(25nm) / LiF(0.5nm) / Al(150nm).

[0219] The preparation method of the blue organic electroluminescent device is as follows:

[0220] The material was placed in a vacuum chamber and evacuated to 1×10 -5 ~1×10 -6 Pa, vacuum evaporating the above materials onto the cleaned ITO substrate in sequence to prepare an OLED device.

[0221] Among them, PBD-1[5%] refers to the doping ratio of the dye, that is, the volume ratio of the main material to the dye PBD-1 is 95:5. In this application example, the main material is H1; HT-1:HI-2[5%] refers to the ratio of the P-type dopant, that is, the volume ratio of the hole material HT-1 and the P-type dopant HI-2 is 95:5, and HT-1 is a hole transport material; HT-1:HI-2[5%] is used as a hole injection layer, and the compound P1 of the present invention forms an electron blocking layer.

[0222] Application Example 2-12

[0223] Application Examples 2-12 each provide a blue organic electroluminescent device. The only difference from Application Example 1 is that the electron blocking layer material compound P1 is replaced with other compounds (see Table 2 below for details). The other preparation steps and conditions are the same as those of Application Example 1.

[0224] Comparative Application Examples 1-3

[0225] Comparative Application Examples 1-3 each provide an organic electroluminescent device, which differs from Application Example 1 only in that the electron blocking layer material compound P1 is replaced with other compounds (see Table 2 below for details), and the other preparation steps and conditions are the same as those of Application Example 1.

[0226] Performance Testing

[0227] Test the brightness, driving voltage, current efficiency and LT95 of the organic electroluminescent devices provided in the above application examples or comparative application examples, where 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 voltage, current efficiency and LT95 are relative values. The specific test results are shown in Table 2 below:

[0228] Table 2

[0229] Electron blocking layer materials <![CDATA[Brightness / (cd / m 2 )]]> Voltage Current efficiency LT95 Application Example 1 P1 1000 0.88 1.18 2.02 Application Example 2 P2 1000 0.86 1.16 1.75 Application Example 3 P3 1000 0.92 1.22 1.88 Application Example 4 P4 1000 0.93 1.27 3.06 Application Example 5 P7 1000 0.92 1.29 3.31 Application Example 6 P9 1000 0.96 1.29 2.26 Application Example 7 P10 1000 0.81 1.31 2.57 Application Example 8 P16 1000 0.80 1.43 2.69 Application Example 9 P17 1000 0.77 1.43 2.19 Application Example 10 P26 1000 0.92 1.89 2.11 Application Example 11 P28 1000 0.81 1.65 2.67 Application Example 12 P40 1000 0.89 1.56 2.69 Comparative Application Example 1 D1 1000 1 1 1 Comparative Application Example 2 D2 1000 0.97 1.14 1.67 Comparative Application Example 3 D3 1000 0.98 1.01 1.26

[0230] It can be seen from Application Examples 4-5 that when in the compound of Formula I, R1 and R2 are both selected from C1-C10 alkyl or C6-C20 aryl, the device life is better.

[0231] As can be seen from the above, the present invention designs the structure of the carbazole compound to make it suitable for use as an electron blocking layer material for an organic electroluminescent device. The organic electroluminescent device prepared thereby has a higher current efficiency and a longer service life.

[0232] Application Examples 13-18, Comparative Application Example 4

[0233] Application Examples 13-18 and Comparative Application Example 4 respectively provide a blue light organic electroluminescent device, which differs from Application Example 1 only in that the main material is H2, and the electron blocking layer material compound P1 is replaced by other compounds (see Table 3 below for details). The other preparation steps and conditions are the same as those of Application Example 1.

[0234] Test the brightness, driving voltage, current efficiency and LT95 of the organic electroluminescent devices provided in the above application examples or comparative application examples, where 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 3 below:

[0235] Table 3

[0236] Electron blocking layer materials <![CDATA[Luminance / (cd / m 2 )]]> Voltage Current efficiency LT95 Application Example 13 P20 1000 0.95 1.08 2.19 Application Example 14 P47 1000 0.94 1.09 2.37 Application Example 15 P48 1000 1.00 1.28 1.89 Application Example 16 P49 1000 0.96 1.23 3.09 Application Example 17 P49D 1000 0.97 1.22 3.39 Application Example 18 P50 1000 1.02 1.46 2.22 Application Example 19 P50D 1000 1.01 1.47 2.87 Comparative Application Example 4 D4 1000 1 1 1

[0237] As can be seen from the above, the present invention designs the structure of the carbazole compound to make it suitable for use as an electron blocking layer material for an organic electroluminescent device. The organic electroluminescent device prepared thereby has a higher current efficiency and a longer service life.

[0238] 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 has a structure shown in the following formula I: wherein R1 and R2 each independently represent any one of H, a C1-C10 alkyl group or a C6-C20 aryl group, and at least one of R1 and R2 represents a C1-C10 alkyl group or a C6-C20 aryl group; R3 represents any one of H, C1-C10 alkyl or C6-C20 aryl; Ring A and Ring B each independently represent a benzene ring or a naphthalene ring; Ar 601 represents a C6-C20 arylene group; n represents 0 or 1, m represents 0 or 1; Dashed lines indicate single bonds or their absence; The hydrogen atoms in the compounds of formula I shown may each independently be replaced by a deuterium atom.

2. The carbazole compound according to claim 1, wherein The carbazole compound has the structure shown in the following formula IA, formula IB, formula IC, and formula ID: Among them, R1, R2, R3, Ring A, Ring B, Ar 601 , n, m have the same definitions as in claim 1.

3. The carbazole compound according to claim 1 or 2, characterized in that R1 and R2 each independently represent any one of H, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, decyl, phenyl, naphthyl, and biphenyl, and more preferably any one of H, methyl, isopropyl, tert-butyl, methylcyclopentyl, methylcyclohexyl, adamantyl, bicyclo[2,2,1]heptyl, bicyclo[2,2,2]octyl, phenyl, naphthyl, and biphenyl; Preferably, R3 represents any one of H, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, decyl, phenyl, naphthyl, and biphenyl, more preferably any one of H, methyl, isopropyl, tert-butyl, methylcyclopentyl, methylcyclohexyl, adamantyl, bicyclo[2,2,1]heptyl, bicyclo[2,2,2]octyl, phenyl, naphthyl, and biphenyl, further preferably any one of H, methyl, tert-butyl, or phenyl; Preferably, the Ar 601 represents any one of phenylene, naphthylene, and biphenylene.

4. The carbazole compound according to any one of claims 1 to 3, characterized in that The ring A and ring B both represent benzene rings; Preferably, one of the ring A and the ring B is a benzene ring, and the other is a naphthalene ring.

5. The carbazole compound according to any one of claims 1 to 4, characterized in that The m represents 1, and n represents 0; Preferably, m represents 1, and n represents 1; Preferably, m represents 0, and n represents 1; Preferably, m represents 0, and n represents 0.

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 substituted or unsubstituted compounds P1 to P51: The substitution means that the hydrogen atoms in Compounds P1 to P51 may each independently be substituted with a deuterium atom.

7. An intermediate, characterized in that The intermediates include the following compounds: Wherein, R1, R2, R3, Ring A, and Ring B have the same definitions as in claim 1; Dashed lines indicate single bonds or their absence; X and Y each independently represent a halogen atom; The intermediates do not include the following compounds: The intermediate is used to prepare the carbazole compound according to any one of claims 1 to 6.

8. The intermediate according to claim 7, characterized in that The intermediates include the following compounds:

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

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

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