Dibenzofuran compound, intermediate and organic electroluminescent device

Abstract

The invention provides a dibenzofuran compound, an intermediate and an organic electroluminescent device. The dibenzofuran compound has a structure as shown in a formula I. Through the structural design of the dibenzofuran compound, the dibenzofuran compound with excellent performance is prepared, and the organic electroluminescent device prepared by taking the dibenzofuran compound as a material of the electron blocking layer has relatively high current efficiency, relatively long service life and relatively low driving voltage.

Description

Technical Field

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

[0002] Compared with other flat panel displays (for example, liquid crystal display (LCD), plasma display panel (PDP), field emission display (FED), etc.), the organic electroluminescent device (OLED) has a simpler structure, various processing advantages, higher brightness, excellent viewing angle characteristics, faster response speed and lower driving voltage. Therefore, it has also been fully developed for use as a light source for flat panel displays (such as wall-mounted TVs, etc.), or as a backlight unit for displays, illuminators, billboards, etc.

[0003] The structure of the organic electroluminescent device is specifically: an anode, a cathode and an organic layer therebetween. In order to improve the efficiency and stability of the organic electroluminescent element, the organic material layer includes multiple layers with different materials. In order to meet people's higher requirements for OLED devices, it is urgent to develop more types of materials in this field to improve the performance of OLED devices in terms of current efficiency, lifespan, etc. Summary of the Invention

[0004] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a dibenzofuran compound, an intermediate and an organic electroluminescent device. By designing the structure of the dibenzofuran compound, the present invention prepares a dibenzofuran compound with excellent performance. Thus, as a material for the electron blocking layer of the OLED device, the prepared organic electroluminescent device has a higher current efficiency, a longer lifespan and a lower driving voltage.

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

[0006] In the first aspect, the present invention provides a dibenzofuran compound, and the dibenzofuran compound has the structure shown in the following formula I:

[0007]

[0008] Wherein, Ar 2 is selected from any one or a combination of at least two of phenyl, naphthyl, biphenyl, 9,9-dimethylfluorenyl, carbazolyl, dibenzofuranyl or dibenzothiophenyl;

[0009] Each hydrogen atom in the compound of formula I can independently be deuterium atom (D), -F, -CN, C1-C12 alkyl, C1-C12 alkoxy, triphenylsilyl ( The dashed line indicates the connection site (the same hereinafter), triphenylmethyl is substituted by at least one of C6-C20 aryl or C6-C20 heteroaryl.

[0010] By designing the structure of dibenzofuran compounds, the present invention prepares dibenzofuran compounds with excellent properties. Thus, as a material for the electron blocking layer of OLED devices, the prepared organic electroluminescent devices have high current efficiency, long lifespan and low driving voltage.

[0011] In the present invention, C1-C12 can be C1, C2, C3, C4, C5, C6, C7, C8, C9 or C12.

[0012] C6-C20 can be C6, C10, C12, C15, C18 or C20, etc.

[0013] In the present invention, "D" represents a deuterium atom. If not separately marked in the present invention, H and hydrogen therein both represent "protium", the same hereinafter.

[0014] The following are the preferred technical solutions of the present invention, but do not 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.

[0015] 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, methylcyclopentyl, hexyl, methylcyclohexyl, heptyl, octyl or adamantyl, bicyclo[2.2.1]heptyl or bicyclo[2.2.2]octyl.

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

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

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

[0019] As a preferred technical solution of the present invention, the Ar 2 is selected from any one of phenyl, naphthyl, biphenyl or 9,9-dimethylfluorenyl, preferably any one of phenyl, naphthyl or biphenyl.

[0020] As a preferred technical solution of the present invention, each hydrogen atom in the compound of formula I can independently be at least one of a deuterium atom (D), -F, -CN, methoxy, ethoxy, propoxy, methyl, ethyl, propyl, tert-butyl, phenyl, biphenyl, naphthyl, 9,9-dimethylfluorenyl, dibenzofuranyl, dibenzothiophenyl, carbazolyl, and triphenylsilyl.

[0021] Preferably, each hydrogen atom in the compound of formula I can independently be at least one of a deuterium atom (D), -F, -CN, phenyl, biphenyl, naphthyl, 9,9-dimethylfluorenyl, dibenzofuranyl, dibenzothiophenyl, carbazolyl, tert-butyl, and methoxy.

[0022] As a preferred technical solution of the present invention, the dibenzofuran compound has any one of the structures shown in formulas I-1 to I-3 as follows:

[0023]

[0024] Wherein, Ar 2 has the same definition as above;

[0025] Each hydrogen atom in the compounds of formulas I-1 to I-3 can independently be substituted by at least one of a deuterium atom (D), -F, -CN, C1-C12 alkyl, C1-C12 alkoxy, triphenylsilyl, triphenylmethyl, C6-C20 aryl, or C6-C20 heteroaryl.

[0026] As a preferred technical solution of the present invention, the dibenzofuran compound is selected from any one of the following substituted or unsubstituted compounds:

[0027]

[0028]

[0029] The substitution means that each hydrogen atom in the dibenzofuran compound can independently be replaced by a deuterium atom. Preferably, the dibenzofuran compound is selected from any one of the following compounds:

[0030]

[0031] It should be noted that in the present invention, there is no special limitation on the preparation method of the above dibenzofuran compounds, and the commonly used preparation methods in the art are applicable.

[0032] In a second aspect, the present invention provides an intermediate, and the intermediate includes the following compounds:

[0033]

[0034] Among them, Ar 2 has the same definition as above;

[0035] X 2 is independently selected from any one of F, Cl, Br, and I;

[0036] The hydrogen atoms in the formula MA compound can each independently be substituted by at least one of deuterium atoms, -F, -CN, C1-C12 alkyl, C1-C12 alkoxy, triphenylsilyl, triphenylmethyl, C6-C20 aryl, or C6-C20 heteroaryl.

[0037] The intermediate is used for preparing the dibenzofuran compound as described in the first aspect.

[0038] Preferably, the intermediate includes the following compounds:

[0039]

[0040] It should be noted that in the present invention, there is no special limitation on the preparation method of the above intermediate, and the commonly used preparation methods in the art are applicable.

[0041] The preparation method of the intermediate of the present invention is exemplified as including the following steps:

[0042]

[0043] Among them, Ar 2 has the same definition as above;

[0044] X 1 and X 2 are each independently selected from any one of -F, -Cl, -Br, and -I, and those skilled in the art can select the specific types of X 1 and X 2 according to common general knowledge;

[0045] The hydrogen atoms in the formula MA compound can each independently be substituted by at least one of deuterium atoms (D), -F, -CN, C1-C12 alkyl, C1-C12 alkoxy, triphenylsilyl, triphenylmethyl, C6-C20 aryl, or C6-C20 heteroaryl.

[0046] In the third aspect, the present invention provides an organic electroluminescent device, which includes an anode, a cathode, and an organic thin film layer disposed between the anode and the cathode;

[0047] The material of the organic thin film layer includes the dibenzofuran compound as described in the first aspect.

[0048] Preferably, the organic thin film layer includes an electron blocking layer, and the electron blocking layer includes a dibenzofuran compound as described in the first aspect.

[0049] Preferably, the light-emitting layer is a phosphorescent light-emitting layer.

[0050] As a preferred technical solution of the present invention, the organic electroluminescent device is a blue organic electroluminescent device.

[0051] In the present invention, the light-emitting layer includes a light-emitting layer host material and a doping material, where the doping material is also called a dye or a phosphorescent light-emitting material. The light-emitting layer host material can be a single compound or a mixture formed by two or more compounds.

[0052] As a preferred technical solution of the present invention, the organic thin film layer includes a light-emitting layer, and the light-emitting layer host material includes at least one of the following substituted or unsubstituted carbazole compounds:

[0053]

[0054]

[0055] The substitution means that each hydrogen atom in the carbazole compound can be independently replaced by a deuterium atom.

[0056] 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.

[0057] The volume percentage content of the host 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 further preferably 85% to 95%.

[0058] In the present invention, the doping material of the light-emitting layer can be a phosphorescent light-emitting material. The phosphorescent light-emitting material, also known as a triplet light-emitting material, refers to the light emitted by a substance from a triplet excited state. The specific selection of the phosphorescent material in the present invention is not particularly limited, and commonly used doping materials for the light-emitting layer in the art are applicable. Exemplarily, it includes but is not limited to: a compound having a structure shown by formula PD:

[0059]

[0060] Among them, M is selected from any one of Ir, Pt, Pd, Os, Ti, Zr, Hf, Eu, Tb, Tm, Cu or Au;

[0061] Y 1 -Y 4Each independently selected from carbon or nitrogen;

[0062] Y 1 and Y 2 can be connected by a single bond or a double bond, and Y 3 and Y 4 can be connected by a single bond or a double bond;

[0063] Cy 1 and Cy 2 Each independently selected from phenyl, naphthyl, fluorenyl, spirofluorenyl, indenyl, pyrrolyl, thienyl, furyl, imidazolyl, pyrazolyl, thiazolyl, isothiazolyl, pyridyl, pyrazinyl, pyrimidinyl, pyridazinyl, quinolinyl, isoquinolinyl, benzoquinolinyl, quinoxalinyl, quinazolinyl, carbazolyl, benzimidazolyl, benzofuranyl, benzothienyl, isobenzothienyl, benzimidazazolyl, benzoxazolyl, triazolyl, tetrazolyl, dioxazolyl, triazinyl, dibenzofuranyl, dibenzothienyl, N-heterocarbazolyl, N-heterodibenzofuranyl, and Cy 1 and Cy 2 can optionally be connected to each other via a single bond or an organic linking group;

[0064] Between any two ligands of M, between two or more ligands, they can be connected by a single bond or a double bond, or can be bridged by O or S, or can be connected by any chemical group or chemical structure to form a structure form that conforms to chemical principles;

[0065] R 91 and R 92 Each independently selected from -H, -D, -F, -Cl, -Br, -I, hydroxyl group, cyano group, nitro group, amino group, amidino group, hydrazino group, hydrazone group, carboxylic acid group, carboxylate group, sulfonic acid group, sulfonate group, phosphoric acid group, phosphate group, -SF 5, a substituted or unsubstituted C1-C60 (such as C1, C5, C10, C15, C20, C25, C30, C35, C40, C45, C50, C55 or C60, etc.) alkyl group, a substituted or unsubstituted C2-C60 (such as C2, C5, C10, C15, C20, C25, C30, C35, C40, C45, C50, C55 or C60, etc.) alkenyl group, a substituted or unsubstituted C2-C60 (such as C2, C5, C10, C15, C20, C25, C30, C35, C40, C45, C50, C55 or C60, etc.) alkynyl group, a substituted or unsubstituted C1-C60 (such as C1, C5, C10, C15, C20, C25, C30, C35, C40, C45, C50, C55 or C60, etc.) alkoxy group, a substituted or unsubstituted C2-C10 (such as C2, C3, C4, C5, C6, C7, C8, C9 or C10) heterocycloalkyl group, a substituted or unsubstituted C6-C60 (such as C6, C12, C15, C18, C24, C30, C32, C36, C40, C42, C54 or C60, etc.) aryl group, a substituted or unsubstituted C6-C60 (such as C6, C12, C15, C18, C24, C30, C32, C36, C40, C42, C54 or C60, etc.) aryloxy group, a substituted or unsubstituted C6-C60 (such as C6, C12, C15, C18, C24, C30, C32, C36, C40, C42, C54 or C60, etc.) arylthio group, a substituted or unsubstituted monovalent non-aromatic fused polycyclic group, a substituted or unsubstituted monovalent non-aromatic fused heteropolycyclic group, any one of them.

[0066] a 1 and a 2 Each independently is an integer selected from 1 to 5, such as 1, 2, 3, 4 or 5;

[0067] b is selected from integers from 0 to 4, such as 0, 1, 2, 3 or 4;

[0068] a is selected from 1, 2 or 3;

[0069] L 1 is a monovalent organic ligand, a divalent organic ligand or a trivalent organic ligand.

[0070] Preferably, the PD compound of the formula is selected from any one of the following compounds:

[0071]

[0072]

[0073]

[0074]

[0075]

[0076]

[0077] 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.

[0078] The material of the hole injection layer includes a P-type dopant. The P-type dopant refers to a substance that coexists with the material of the hole injection layer in the OLED device, can oxidize the material of the hole injection layer, and thus serves as an electron acceptor, which can promote the movement of holes in 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 -0.2 V, preferably greater than -0.1 eV, more preferably greater than 0 eV, still more preferably greater than 0.1 eV, and even more preferably greater than 0.2 eV.

[0079] The P-type dopant exists in the hole injection layer in a volume ratio of 1% to 10% by volume (for example, it can be 1%, 2%, 4%, 6%, 8%, or 10%, etc.). In the present invention, no special limitation is imposed on the type of the P-type dopant. Exemplarily, the compounds shown as D-1 to D-13 disclosed in CN113728453A or the compounds shown as HI-1 to HI-9 described below can be selected:

[0080]

[0081]

[0082] In the present invention, the hole layer material (including the hole injection layer, the hole transport layer, and the electron blocking layer) has the structure shown by the following formula HT-GH4:

[0083]

[0084] Among them, L 41 is selected from a single bond, an aryl group of C6-C40 (for example, it can be C6, C8, C10, C12, C16, C20, C24, C28, C30, C32, C36, or C40, etc.), and a heteroaryl group of C6-C20 (for example, it can be C6, C8, C10, C12, C16, or C20, etc.);

[0085] Ar 41 Ar 42Each independently selected from C6-C40 (such as C6, C8, C10, C12, C16, C20, C24, C28, C30, C32, C36 or C40, etc.) aryl, C6-C20 (such as C6, C8, C10, C12, C16 or C20, etc.) heteroaryl;

[0086] 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 substituents of the substituted are selected from C1-C6 (such as C1, C2, C3, C4, C5 or C6) alkyl, C1-C6 (such as C1, C2, C3, C4, C5 or C6) alkoxy, dibenzofuranyl), naphthyl, triphenylene, fluoranthenyl, 9,9-dimethylfluorenyl, biphenyl, substituted or unsubstituted dibenzofuranyl (the substituents of the substituted are phenyl), substituted or unsubstituted dibenzothiophenyl (the substituents of the substituted are phenyl), dibenzofuran-substituted thiophenyl, any one of C1-C6 (such as C1, C2, C3, C4, C5 or C6) alkyl, R 41 , R 42 can be connected into a ring through a single bond.

[0087] In the present invention, the hole layer material (including hole injection layer, hole transport layer and electron blocking layer) further includes a compound having a structure shown in Formula ⅠA or a compound having a structure shown in Formula ⅠB:

[0088]

[0089] Among them, L is selected from any one of C6-C40 (such as C6, C8, C10, C12, C16, C20, C24, C28, C30, C32, C36 or C40, etc.) arylene, arylenedibenzofuranyl or arylenedibenzothiophenyl;

[0090] m is an integer between 0 and 4 (such as 0, 1, 2, 3 or 4), and n is selected from 0 or 1;

[0091] Ar is selected from any one of aryltriphenylene, arylfluoranthenyl, arylenedibenzofuranyl or arylenedibenzothiophenyl;

[0092] Ar 1 and Ar 2Each is independently selected from any one of aryl, dibenzofuranyl or dibenzothiophenyl containing C6-C40 (such as C6, C8, C10, C12, C16, C20, C24, C28, C30, C32, C36 or C40, etc.);

[0093] Ar 1 Between and Ar, Ar 2 Between and Ar, and Ar 1 Ar, 2 Between them can be independently connected or bridged by a single bond, O, S, CR 1 R 2 , NR.

[0094] R, R 1 R, 2 Each is independently selected from any one of C1-C20 (such as C1, C2, C4, C6, C8, C10, C12, C14, C16, C18 or C20, etc.) alkyl, C6-C40 (such as C6, C8, C10, C12, C16, C20, C24, C28, C30, C32, C36 or C40, etc.) aryl, dibenzofuranyl or dibenzothiophenyl;

[0095] The hydrogen atoms in the compound of formula IB and the compound of formula IA can be independently replaced by at least one of -F, -CN, -D (deuterium atom), C1-C6 alkyl, C1-C6 alkoxy, phenyl, biphenyl, naphthyl, phenanthryl, anthryl, fluorenyl, benzo[a]fluorenyl, dibenzo[a,h]fluorenyl, triphenylenyl, fluoranthenyl, pyrenyl, perylenyl, spirofluorene, indenofluorene or hydrogenated benzoanthracenyl.

[0096] Preferably, the Ar is fluoranthenylene, and m + n > 1.

[0097] Preferably, the 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 (such as methyl, ethyl or propyl), C1-C3 alkoxy (such as methoxy, ethoxy or propoxy), phenyl, biphenyl, triphenylenyl, fluoranthenyl.

[0098] Preferably, the L, Ar 1 Ar, 2 Each is independently selected from at least one of phenyl, biphenyl, naphthyl, phenanthryl, anthryl, fluorenyl, benzo[a]fluorenyl, dibenzo[a,h]fluorenyl, triphenylenyl, fluoranthenyl, pyrenyl, perylenyl, spirofluorene, indenofluorene or hydrogenated benzoanthracenyl.

[0099] Preferably, the compound of formula IB is selected from any one of the following compounds:

[0100]

[0101]

[0102] In the OLED device provided by the present invention, in addition to the compounds represented by formula HT-GH4, formula IB compounds, and formula IA compounds, the hole transport layer material 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 more than 3 N atoms are used because the HOMO of triarylamine compounds or carbazole compounds containing more than 3 N atoms is relatively high (with a smaller absolute value), making them more suitable as hole injection layer materials. Triarylamine compounds or carbazole compounds containing 2 or 1 N atom can be used as hole transport layer materials. Some compounds containing 1 N atom or carbazole compounds, if they have a relatively high LUMO, can also be used as electron blocking layer materials.

[0103] When the triarylamine compound or carbazole compound is used as the hole transport layer material, the hole transport layer material has the following structure:

[0104]

[0105] Wherein, Ar 601 ~Ar 609 are each independently selected from substituted or unsubstituted C6-C40 (such as C6, C8, C10, C12, C16, C20, C24, C28, C30, C32, C36 or C40, etc.) aryl groups, substituted or unsubstituted dibenzofuranyl groups, substituted or unsubstituted dibenzothiophenyl groups, substituted or unsubstituted naphthobenzofuranyl groups, substituted or unsubstituted naphthobenzothiophenyl groups, substituted or unsubstituted dinaphthofuranyl groups, substituted or unsubstituted dinaphthothiophenyl groups;

[0106] And for Ar 601 ~Ar 609 where Ar 601 ~Ar 609 are adjacent or connected to the same N atom, they can be connected by a single bond or bridged by O, S, CR 701 R 702 、NR 703 ;

[0107] R 701 、R 702 、R 703Selected from C6-C40 (such as C6, C8, C10, C12, C16, C20, C24, C28, C30, C32, C36 or C40, etc.) aryl groups, C6-C20 (such as C6, C8, C10, C12, C16 or C20, etc.) heteroaryl groups, C1-C6 (such as C1, C2, C3, C4, C5 or C6) alkyl groups, and R 701 、R 702 can be connected by a single bond.

[0108] The hole blocking layer (HBL) can confine holes and / or excitons within the light-emitting layer to improve the current efficiency and lifetime of the device. Compared with the light-emitting layer material closest to the HBL interface, the HBL material has a lower HOMO (larger absolute value) and / or a higher triplet energy.

[0109] The electron transport layer (ETL) can include materials capable of transporting electrons. The electron transport layer can be intrinsic (undoped) or doped, and doping can be used to enhance conductivity. In the present invention, there is no special limitation on the ETL material, and any metal complex or organic compound can be used as long as it can transport electrons. Generally, the electron transport layer material contains at least one of the following structural fragments: pyridine structure, pyrimidine structure, triazine structure, benzimidazole structure, benzoxazole structure, benzothiazole structure, naphthyridine structure, phenanthridine structure, carbazole structure, dibenzofuran structure, dibenzothiophene structure.

[0110] In the present invention, there is no special limitation on the electron transport layer material, and exemplary ones include but are not limited to:

[0111]

[0112]

[0113]

[0114]

[0115]

[0116]

[0117]

[0118] In the present invention, the material of the cathode is a metal with a low work function (such as alkaline earth metals, alkali metals, main group metals or lanthanide elements (such as Ca, Ba, Mg, Al, In, Mg, Yb, Sm, etc.)), a metal alloy composed of multiple metals (an alloy composed of an alkali metal or an alkaline earth metal and silver, such as an alloy composed of magnesium and silver), or a multi-layer structure. If the cathode material is a multi-layer structure, in addition to the metals mentioned above, other metals with a relatively high work function, such as Ag or Al, can also be used. In this case, a combination of the metals is usually used, such as Ca / Ag, Mg / Ag or Ba / Ag.

[0119] It is also possible to select a thin intermediate layer of a material with a high dielectric constant to be introduced between the metal cathode and the organic semiconductor to form a multi-layer structure; the material with a high dielectric constant can also be called an electron injection material, and fluorides of alkali metals or alkaline earth metals, as well as corresponding oxides or carbonates (such as LiF, Li 2 O, BaF 2 , MgO, NaF, CsF, Cs 2 CO 3 etc.) or lithium quinolate (LiQ) can be selected.

[0120] Compared with the prior art, the present invention has the following beneficial effects:

[0121] In the present invention, by designing the structure of the dibenzofuran compound, it is suitable as an electron blocking layer material for organic electroluminescent devices. The organic electroluminescent device prepared therefrom has a high current efficiency, a long lifespan and a low driving voltage. Detailed implementation mode

[0122] To facilitate the understanding of the present invention, the following examples are listed. Those skilled in the art should understand that the examples are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0123] Synthesis Example 1

[0124] This synthesis example provides Compound A1 and its synthesis method, and the synthesis method is as follows:

[0125]

[0126] (1) Synthesis of Intermediate A1-1

[0127] Under a nitrogen atmosphere, 70 mL of toluene, 30 mL of ethanol, and 20 mL of water were added to a three-necked flask. Then, 2.5 g of compound 2-bromodibenzofuran, 3.0 g of compound 3-phenyl-4-fluoro-phenylboronic acid pinacol ester, 2.12 g of sodium carbonate, and 0.23 g of tetrakis(triphenylphosphine)palladium were added thereto. The temperature was slowly raised to reflux for 6 h, then cooled to room temperature, water was added for liquid separation. After washing the organic layer with water, it was dried with magnesium sulfate. After removing the desiccant, it was concentrated to dryness, and subjected to silica gel column chromatography separation, eluted with petroleum ether, to obtain intermediate A1-1 (2.2 g).

[0128] The obtained intermediate A1-1 was subjected to mass spectrometry detection, and the measured mass-to-charge ratio (m / z) was: 338.11.

[0129] (2) Synthesis of compound A1

[0130] Under nitrogen protection, 3.4 g of intermediate A1-1, 1.7 g of carbazole, 6.1 g of cesium carbonate, and 80 mL of DMF were successively added to a three-necked flask. The temperature was raised to 100 °C for reaction for 4 h, then raised to reflux for reaction for 2 h, cooled, water was added for filtration. The obtained solid was dried under reduced pressure, and then subjected to silica gel column chromatography separation, eluted with petroleum ether:ethyl acetate = 10:1 (volume ratio), to obtain compound A1 (3.1 g).

[0131] The obtained compound A1 was subjected to mass spectrometry detection, and the measured mass-to-charge ratio (m / z) was 485.18.

[0132] Synthesis Example 2

[0133] This synthesis example provides compound A2 and its synthesis method. The synthesis method is as follows:

[0134]

[0135] (1) Synthesis of intermediate A2-1

[0136] Referring to the synthesis method of intermediate A1-1, intermediate A2-1 was prepared.

[0137] The obtained intermediate A2-1 was subjected to mass spectrometry detection, and the measured mass-to-charge ratio (m / z) was: 388.13.

[0138] (2) Synthesis of compound A2

[0139] Referring to the synthesis method of compound A1, compound A2 was prepared.

[0140] The obtained compound A2 was subjected to mass spectrometry detection, and the measured mass-to-charge ratio (m / z) was: 535.19.

[0141] Synthesis Example 3

[0142] This synthesis example provides compound A3 and its synthesis method. The synthesis method is as follows:

[0143]

[0144] (1) Synthesis of intermediate A3-1

[0145] Refer to the synthesis method of intermediate A1-1 to prepare intermediate A3-1.

[0146] Perform mass spectrometry detection on the obtained intermediate A3-1, and the measured mass-to-charge ratio (m / z) is: 338.11.

[0147] (2) Synthesis of compound A3

[0148] Refer to the synthesis method of compound A1 to prepare compound A3.

[0149] Perform mass spectrometry detection on the obtained compound A3, and the measured mass-to-charge ratio (m / z) is: 561.21.

[0150] Synthesis example 4

[0151] This synthesis example provides compound A4 and its synthesis method. The synthesis method is as follows:

[0152]

[0153] (1) Synthesis of intermediate A4-1

[0154] Refer to the synthesis method of intermediate A1-1 to prepare intermediate A4-1.

[0155] Perform mass spectrometry detection on the obtained intermediate A4-1, and the measured mass-to-charge ratio (m / z) is: 414.14.

[0156] (2) Synthesis of compound A4

[0157] Refer to the synthesis method of compound A1 to prepare compound A4.

[0158] Perform mass spectrometry detection on the obtained compound A4, and the measured mass-to-charge ratio (m / z) is: 561.21.

[0159] For compounds whose specific synthesis methods are not listed, the above examples can be referred to and combined with the common general knowledge in the art for synthesis.

[0160] The specific structures of some compounds used in the following application examples and comparative application examples are as follows:

[0161]

[0162]

[0163] The synthesis method of P1 is as follows:

[0164]

[0165] (1) Synthesis of intermediate P1-1

[0166] Under a nitrogen atmosphere, 60 mL of toluene, 30 mL of ethanol, and 20 mL of water were added to a three-necked flask, and then 3.2 g of compound 3-bromo-9-phenylcarbazole, 3.0 g of compound 3-phenyl-4-fluoro-phenylboronic acid pinacol ester, 2.12 g of sodium carbonate, and 0.23 g of tetrakis(triphenylphosphine)palladium were added thereto. The temperature was slowly raised to reflux for 6 h, cooled to room temperature, water was added for liquid separation, the organic layer was washed with water, dried over magnesium sulfate, the desiccant was removed, concentrated to dryness, and subjected to silica gel column chromatography separation, eluted with petroleum ether to obtain intermediate P1-1 (3.7 g).

[0167] The obtained intermediate P1-1 was subjected to mass spectrometry detection, and the measured mass-to-charge ratio (m / z) was: 413.16.

[0168] (2) Synthesis of compound P1

[0169] Under nitrogen protection, 4.1 g of intermediate P1-1, 1.7 g of carbazole, 6.1 g of cesium carbonate, and 90 mL of DMF were successively added to a three-necked flask, the temperature was raised to 100 °C for reaction for 4 h, then raised to reflux for reaction for 2 h, cooled, water was added for filtration, a solid was precipitated, the solid was dried under reduced pressure, and subjected to silica gel column chromatography separation, eluted with petroleum ether:ethyl acetate = 10:1 (volume ratio) to obtain compound P1 (4.9 g)

[0170] The obtained compound P1 was subjected to mass spectrometry detection, and the measured mass-to-charge ratio (m / z) was 560.23.

[0171] Application Example 1

[0172] This application example provides a blue organic electroluminescent device, using the compound A1 provided by the present invention as an electron blocking layer material. The structure of the blue organic electroluminescent device is as follows:

[0173] ITO / HT-1:HI-2[5%](80 nm) / HT-1(30 nm) / electron blocking layer material(20 nm) / P1:PBD-1[5%](35 nm) / ETL-1(25 nm) / LiF(0.5 nm) / Al(150 nm).

[0174] The preparation method of the blue organic electroluminescent device is as follows:

[0175] Place the materials in a vacuum chamber, evacuate to 1×10 -5 ~1×10-6 Pa, the above materials were sequentially vacuum-evaporated onto the cleaned ITO substrate to fabricate the OLED device.

[0176] Among them, PBD-1[5%] refers to the doping ratio of the dye, that is, the volume ratio of the host material P1 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, and HT-1 is a hole transport material; HT-1:HI-2[5%] is used as the hole injection layer material, and compound A1 is the electron blocking layer material.

[0177] Application Example 2-12

[0178] Application Example 2-12 respectively provides a blue organic electroluminescent device, which is only different from Application Example 1 in that the electron blocking layer material compound A1 is replaced with other compounds, and the host material P1 of the light-emitting layer is replaced with P2 as needed (see Table 1 below), and other preparation steps and conditions are the same as those in Application Example 1.

[0179] Comparative Application Example 1-2

[0180] Comparative Application Example 1-2 respectively provides an organic electroluminescent device, which is only different from Application Example 1 in that the electron blocking layer material compound A1 is replaced with other compounds (see Table 1 below), and other preparation steps and conditions are the same as those in Application Example 1.

[0181] Performance Test

[0182] The brightness, driving voltage, current efficiency and LT95 of the organic electroluminescent devices provided above were tested. Among them, the current efficiency is the corresponding value when the brightness is 1000 cd / m 2 The LT95 refers to the time required for the device efficiency to drop to 95% of the efficiency corresponding to the initial current density while keeping the initial current density of the device at 10 mA / cm 2 unchanged. Among them, the driving voltage, current efficiency and LT95 are relative values. The specific test results are shown in Table 1 below:

[0183] Table 1

[0184]

[0185] As can be seen from the above, in the present invention, by designing the structure of the dibenzofuran compounds, they are suitable for use as the electron blocking layer material of the organic electroluminescent device, and the prepared organic electroluminescent device has high current efficiency, long life and low driving voltage.

[0186] It can be seen from the comparison between Application Example 1 and Application Example 11 that when the host material of the light-emitting layer is selected from Compound P1, in combination with the electron blocking layer material provided by the present invention, the comprehensive performance of the organic electroluminescent device can be further improved.

[0187] It can be seen from the comparison between Application Example 2 and Application Example 12 that when the host material of the light-emitting layer is selected from Compound P1, in combination with the electron blocking layer material provided by the present invention, the prepared organic electroluminescent device has high performance.

[0188] In summary, in the present invention, by designing the structure of the dibenzofuran compound, it is suitable as the electron blocking layer material of the organic electroluminescent device. The organic electroluminescent device prepared therefrom has high current efficiency, long lifespan and low driving voltage.

[0189] The applicant declares that the present invention uses the above embodiments to illustrate the detailed process flow of the present invention, but the present invention is not limited to the above detailed process flow, that is, it does not mean that the present invention must rely on the above detailed process flow to be implemented. Those skilled in the art should understand that any improvement to the present invention, the equivalent substitution of each raw material of the product of the present invention, the addition of auxiliary components, the selection of specific methods, etc., all fall within the protection scope and the disclosure scope of the present invention.

Claims

1. A dibenzofuran compound, characterized in that: The dibenzofuran compound has a structure shown in the following formula I: Wherein, Ar2 is selected from any one or a combination of at least two of phenyl, naphthyl, biphenyl, 9,9-dimethylfluorenyl, carbazolyl, dibenzofuranyl or dibenzothiophenyl; The hydrogen atoms in the compound of formula I may be independently substituted by at least one of a deuterium atom, -F, -CN, a C1-C12 alkyl group, a C1-C12 alkoxy group, a triphenylsilyl group, a triphenylmethyl group, a C6-C20 aryl group or a C6-C20 heteroaryl group.

2. The dibenzofuran compound according to claim 1, characterized in that The C1-C12 alkyl group is selected from any one of methyl, ethyl, propyl, butyl, pentyl, methylcyclopentyl, hexyl, methylcyclohexyl, heptyl, octyl or adamantyl, bicyclo[2.2.1]heptyl or bicyclo[2.2.2]octyl; Preferably, the C1-C12 alkoxy group is selected from any one of methoxy, ethoxy, propoxy, butoxy, pentyloxy or hexyloxy; Preferably, the C6-C20 aryl group is selected from any one of phenyl, naphthyl, biphenyl or 9,9-dimethylfluorenyl; Preferably, the C6-C20 heteroaryl group is selected from any one of a carbazolyl group, a dibenzofuranyl group or a dibenzothiophenyl group.

3. The dibenzofuran compound according to claim 1 or 2, characterized in that: The Ar2 is selected from any one of phenyl, naphthyl, biphenyl or 9,9-dimethylfluorenyl, preferably any one of phenyl, naphthyl or biphenyl.

4. The dibenzofuran compound according to any one of claims 1 to 3, characterized in that: The hydrogen atoms in the compound of formula I can be replaced by at least one of a deuterium atom, -F, -CN, a methoxy group, an ethoxy group, a propoxy group, a methyl group, an ethyl group, a propyl group, a tert-butyl group, a phenyl group, a biphenyl group, a naphthyl group, a 9,9-dimethylfluorenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a carbazolyl group, and a triphenylsilyl group; Preferably, the hydrogen atoms in the compound of formula I can be replaced independently by at least one of a deuterium atom (D), -F, -CN, phenyl, biphenyl, naphthyl, 9,9-dimethylfluorenyl, dibenzofuranyl, dibenzothiophenyl, carbazolyl, tert-butyl, and methoxy.

5. The dibenzofuran compound according to any one of claims 1 to 4, characterized in that: The dibenzofuran compound has any one of the structures shown in the following formula I-1 to formula I-3: Wherein, Ar2 has the same definition as in claim 1; The hydrogen atoms in the compounds of Formula I-1 to Formula I-3 may each independently be substituted by at least one of a deuterium atom, -F, -CN, a C1-C12 alkyl group, a C1-C12 alkoxy group, a triphenylsilyl group, a triphenylmethyl group, a C6-C20 aryl group or a C6-C20 heteroaryl group.

6. The dibenzofuran compound according to any one of claims 1 to 5, characterized in that: The dibenzofuran compound is selected from any one of the following substituted or unsubstituted compounds: The substitution means that the hydrogen atoms in the dibenzofuran compound can be independently replaced by deuterium atoms; preferably, the dibenzofuran compound is selected from any one of the following compounds:

7. An intermediate, characterized in that The intermediates include the following compounds: Wherein, Ar2 has the same definition as in claim 1; X2 is selected from any one of F, Cl, Br, and I; The hydrogen atoms in the compound of formula MA may each independently be substituted by at least one of a deuterium atom, -F, -CN, a C1-C12 alkyl group, a C1-C12 alkoxy group, a triphenylsilyl group, a triphenylmethyl group, a C6-C20 aryl group or a C6-C20 heteroaryl group; The intermediate is used to prepare the dibenzofuran compound as claimed in 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, comprising 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 the dibenzofuran compound according to any one of claims 1 to 6; Preferably, the organic thin film layer comprises an electron blocking layer, and the electron blocking layer comprises the dibenzofuran compound according to any one of claims 1 to 6; Preferably, the light-emitting layer is a phosphorescent light-emitting layer; As a preferred technical solution of the present invention, the organic electroluminescent device is a blue light organic electroluminescent device.

10. The organic electroluminescent device according to claim 9, characterized in that: The organic thin film layer includes a light-emitting layer, and the main material of the light-emitting layer includes at least one of the following substituted or unsubstituted carbazole compounds: The substitution means that the hydrogen atoms in the carbazole compound can be independently replaced by deuterium atoms.

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