An organic compound and its application, and an organic electroluminescent device containing the same

Abstract

The present invention relates to a compound and its application, wherein the compound has a structure shown in Formula I. The compound provided by the present invention uses benzonitrile as a parent core, is substituted with four carbazole groups, and at least one carbazole is substituted with a 3-alkyl monosubstituted (Hy-2), the compound can make the luminescence blue-shifted, and the degree of conjugation is low, so that the luminescence is bluer, and is suitable for deep blue light devices. And while protecting the active site of the compound, its carrier transport performance can be improved to a certain extent, thereby improving the luminous efficiency of the device and reducing the voltage.

Description

Technical Field

[0001] The present invention relates to the technical field of organic electroluminescence, and in particular to an organic compound and application thereof, and an organic electroluminescence device containing the organic compound. Background Art

[0002] Optoelectronic devices using organic materials are becoming increasingly popular for a number of reasons. Many of the materials used to make such devices are relatively cheap, and optoelectronic devices have potential cost advantages over inorganic devices. In the structure of organic electroluminescent devices in the display and lighting fields, blue fluorescence is generally used in combination with red and green phosphorescent materials. Recently, there have been reports of TADF (Thermally Activated Delayed Fluorescence) fluorescent dye compounds based on benzonitrile carbazole. This type of compound is based on benzonitrile as an electron acceptor, with multiple carbazoles attached to the benzene ring as electron donors, and has a distinct separation of HOMO and LUMO orbitals. For example, compounds C1 to C3:

[0003]

[0004] This type of material uses carbazole as an electron-donating group and introduces a large steric hindrance protecting group at the active site of carbazole, which is beneficial to prevent Dexter energy transfer and inhibit exciton quenching. However, on the one hand, the emission peak of this type of material is difficult to reach the deep blue light region, and it is often difficult to achieve high efficiency when used in deep blue light devices. On the other hand, the use of large steric hindrance protecting groups often weakens the carrier migration ability of the material, resulting in high voltage. In addition, the molecular weight of this type of material is relatively large, and the sublimation temperature is relatively high, which is not conducive to evaporation. Due to these factors, it is difficult to achieve mass production and application of this type of material.

[0005] Therefore, there is an urgent need to develop a new type of luminescent material in this field so that when it is applied to deep blue light devices, it can achieve higher luminescence efficiency and lower driving voltage, while also having a higher sublimation temperature to facilitate evaporation. Summary of the invention

[0006] One of the purposes of the present invention is to provide a compound, which is a thermally activated delayed fluorescent material, suitable for deep blue light devices, and has high luminous efficiency and low driving voltage, low sublimation temperature, and is conducive to evaporation.

[0007] To achieve this object, the present invention adopts the following technical solutions:

[0008] The present invention provides a compound having a structure shown in Formula I;

[0009]

[0010] The R1, R2, R3 and R4 each independently have a structure represented by formula (Hy-1), formula (Hy-2) or formula (Hy-3), and at least one (e.g., one, two, three or four) has a structure represented by formula (Hy-2);

[0011]

[0012] Wherein, * represents the connecting bond of the group;

[0013] The X 1 ~X 6 Each independently selected from N or CR5, X 7 and X 8 are each independently selected from N or CH;

[0014] The R5 is selected from one of hydrogen, substituted or unsubstituted C1-C10 alkoxy, halogen, cyano, nitro, hydroxyl, substituted or unsubstituted C1-C10 silyl, amino, substituted or unsubstituted C6-C30 arylamino, substituted or unsubstituted C3-C30 heteroarylamino, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C3-C30 heteroaryl, preferably hydrogen;

[0015] The Ra and Rb are each independently selected from a substituted or unsubstituted C1-C10 chain alkyl group, a substituted or unsubstituted C3-C10 cycloalkyl group, a substituted or unsubstituted C1-C10 alkoxy group, a halogen, a cyano group, a nitro group, a hydroxyl group, a substituted or unsubstituted C1-C10 silyl group, an amino group, a substituted or unsubstituted C6-C30 arylamino group, a substituted or unsubstituted C3-C30 heteroarylamino group, a substituted or unsubstituted C6-C30 aryl group, or a substituted or unsubstituted C3-C30 heteroaryl group;

[0016] The Rc is selected from any one of a methyl group, a substituted or unsubstituted C4-C18 chain alkyl group, and a substituted or unsubstituted C3-C20 cycloalkyl group;

[0017] When the above-mentioned groups have substituents, the substituents are selected from one or a combination of at least two of halogen, cyano, nitro, hydroxyl, amino, C1-C10 chain alkyl, C3-C10 cycloalkyl, C1-10 alkoxy, C1-C10 silyl, C1-C6 thioalkoxy, C6-C30 arylamino, C3-C30 heteroarylamino, C6-C30 monocyclic aryl, C10-C30 condensed ring aryl, C3-C30 monocyclic heteroaryl, C6-C30 condensed ring heteroaryl. The above-mentioned "substituted or unsubstituted" groups may be substituted with one substituent or with multiple substituents. When there are multiple substituents, they may be selected from different substituents. When the same expressions are involved in the present invention, they all have the same meaning, and the selection range of substituents is as shown above and will not be repeated one by one.

[0018] In this manual, C3 to C 20 The cycloalkyl group includes a monocyclic alkyl group and a polycyclic alkyl group.

[0019] Wherein, a monocyclic alkyl group refers to an alkyl group containing a single cyclic structure; as an example, the monocyclic alkyl group can be selected from one of the following structures:

[0020]

[0021] Cyclopentyl and cyclohexyl are preferred.

[0022] The above-mentioned polycycloalkyl group refers to a structure composed of two or more cycloalkyl groups sharing one or more carbon atoms on the ring; as an example, the polycycloalkyl group can be selected from one of the following structures:

[0023]

[0024] In the present specification, the expression of Ca to Cb represents that the number of carbon atoms in the group is a to b. Unless otherwise specified, the number of carbon atoms generally does not include the number of carbon atoms in the substituent.

[0025] In the present specification, the expression of a ring structure crossed by “—” indicates that the connection site is any position on the ring structure that can form a bond.

[0026] In the present specification, “each independently” means that when there are multiple subjects, they may be the same as or different from each other.

[0027] In the present invention, the expression of chemical elements, unless otherwise specified, generally includes the concept of isotopes thereof. For example, the expression "hydrogen (H)" includes its isotopes. 1 H (hydrogen or H), 2 The concept of H (deuterium or D); carbon (C) includes 12 C. 13 C, etc., no further details.

[0028] The heteroatom in the present invention generally refers to an atom or an atom group selected from N, O, S, P, Si and Se, preferably selected from N, O and S.

[0029] In the present specification, examples of halogen include fluorine, chlorine, bromine, and iodine.

[0030] In the present invention, the substituted or unsubstituted C6-C60 aryl includes a monocyclic aryl and a condensed aryl, preferably a C6-C30 aryl, and more preferably a C6-C20 aryl. The so-called monocyclic aryl refers to a molecule containing at least one phenyl group. When the molecule contains at least two phenyl groups, the phenyl groups are independent of each other and connected by a single bond, such as phenyl, biphenyl, terphenyl, etc. Specifically, the biphenyl includes 2-biphenyl, 3-biphenyl and 4-biphenyl; the terphenyl includes p-terphenyl-4-yl, p-terphenyl-3-yl, p-terphenyl-2-yl, m-terphenyl-4-yl, m-terphenyl-3-yl and m-terphenyl-2-yl. Condensed aryl refers to a molecule containing at least two aromatic rings, and the aromatic rings are not independent of each other but share two adjacent carbon atoms to condense each other. For example, naphthyl, anthracenyl, phenanthrenyl, indenyl, fluorenyl, fluoranthenyl, triphenylene, pyrenyl, peryl, The naphthyl group includes 1-naphthyl or 2-naphthyl; the anthracenyl group is selected from 1-anthracenyl, 2-anthracenyl and 9-anthracenyl; the fluorenyl group is selected from 1-fluorenyl, 2-fluorenyl, 3-fluorenyl, 4-fluorenyl and 9-fluorenyl; the pyrenyl group is selected from 1-pyrenyl, 2-pyrenyl and 4-pyrenyl; the naphthacenyl group is selected from 1-naphthacenyl, 2-naphthacenyl and 9-naphthacenyl. The fluorene derivative group is selected from 9,9-dimethylfluorenyl, 9,9-diethylfluorenyl, 9,9-dipropylfluorenyl, 9,9-dibutylfluorenyl, 9,9-dipentylfluorenyl, 9,9-dihexylfluorenyl, 9,9-diphenylfluorenyl, 9,9-dinaphthylfluorenyl, 9,9'-spirobifluorene and benzofluorenyl.

[0031] The C3-C60 heteroaryl mentioned in the present invention includes monocyclic heteroaryl and condensed ring heteroaryl, preferably C3-C30 heteroaryl, more preferably C4-C20 heteroaryl, and more preferably C5-C12 heteroaryl. Monocyclic heteroaryl refers to a molecule containing at least one heteroaryl. When the molecule contains one heteroaryl and other groups (such as aryl, heteroaryl, alkyl, etc.), the heteroaryl and other groups are independent of each other and connected by a single bond. Examples of monocyclic heteroaryl include furanyl, thienyl, pyrrolyl, pyridyl, etc. Condensed ring heteroaryl refers to a molecule containing at least one aromatic heterocycle and one aromatic ring (aromatic heterocycle or aromatic ring), and the two are not independent of each other but share two adjacent atoms and are fused to each other. Examples of fused ring heteroaryl groups include benzofuranyl, benzothiophenyl, isobenzofuranyl, indolyl, dibenzofuranyl, dibenzothiophenyl, carbazolyl, acridinyl, isobenzofuranyl, isobenzothiophenyl, benzocarbazolyl, azacarbazolyl, phenothiazinyl, phenazinyl, 9-phenylcarbazolyl, 9-naphthylcarbazolyl, dibenzocarbazolyl, indolocarbazolyl and the like.

[0032] Specific examples of the arylene group in the present invention include divalent groups obtained by removing one hydrogen atom from the above-mentioned aryl groups. Specific examples of the heteroarylene group in the present invention include divalent groups obtained by removing one hydrogen atom from the above-mentioned heteroaryl groups.

[0033] The aryloxy group in the present invention includes a monovalent group composed of the above-mentioned aryl group and heteroaryl group and oxygen.

[0034] Examples of the C6-C30 arylamino group mentioned in the present invention include phenylamino, methylphenylamino, naphthylamino, anthracenylamino, phenanthrenylamino, and biphenylamino.

[0035] Examples of the C3-C30 heteroarylamino group mentioned in the present invention include pyridylamino, pyrimidinylamino, dibenzofuranylamino and the like.

[0036] In the present invention, the carbon number of the C1-C10 chain alkyl group may be C2, C3, C4, C5, C6, C7, C8, C9, C10, etc.; the carbon number of the C1-C10 alkoxy group may be C2, C3, C4, C5, C6, C7, C8, C9, C10, etc.; the carbon number of the C1-C10 silyl group may be C2, C3, C4, C5, C6, C7, C8, C9, C10, etc.; the carbon number of the C6-C30 arylamino group may be C10, C12, C14, C16, C18, C20, C26, C28, etc.; the carbon number of the C3-C30 heteroarylamino group may be C3, C4, C6, C8, C10, C12, C14, C16, C18, C20, C26, C28, etc.; the carbon number of the C6-C30 aryl group may be C10, C12, C14, C16, C18, C20, C26, C28, etc.; the carbon number of the C3-C30 heteroaryl group may be C3, C4, C6, C8, C10, C12, C14, C16, C18, C20, C26, C28, etc.;

[0037] The carbon number of the C6-C30 monocyclic aromatic group may be C10, C12, C14, C16, C18, C20, C26, C28, etc.; the carbon number of the C10-C30 condensed ring aromatic group may be C10, C12, C14, C16, C18, C20, C26, C28, etc.; the carbon number of the C3-C30 monocyclic heteroaromatic group may be C3, C4, C6, C8, C10, C12, C14, C16, C18, C20, C26, C28, etc.; the carbon number of the C6-C30 condensed ring heteroaromatic group may be C10, C12, C14, C16, C18, C20, C26, C28, etc.

[0038] The compound provided by the present invention uses benzonitrile as the parent core, substituted with four carbazole groups, and at least one carbazole is substituted at the 3-position (Hy-2), and the substituent is a methyl group, a substituted or unsubstituted C4-C18 chain alkyl group, a substituted or unsubstituted C3-C20 cycloalkyl group, the methyl group has strong rigidity, can improve the luminous efficiency of the molecule, is conducive to the improvement of device efficiency, the substituted or unsubstituted C4-C18 chain alkyl group, the substituted or unsubstituted C3-C20 cycloalkyl group has a large volume, can increase the intermolecular distance, prevent exciton quenching, is conducive to the improvement of luminous efficiency, especially the compound can make the luminescence blue shift, and the degree of conjugation is low, so that the luminescence is bluer, suitable for deep blue light devices. And while protecting the active site of the compound, its carrier transport performance can be improved to a certain extent, thereby improving the luminous efficiency of the device and reducing the voltage.

[0039] In addition, the intermolecular interactions of the compound provided by the present invention are relatively weak, and thus the sublimation temperature can be significantly reduced, which is beneficial to the evaporation of the device.

[0040] Preferably, the (Hy-2) has a structure shown in formula (Hy-2-1);

[0041] R C With the same limited scope as before.

[0042] Preferably, the Rc is selected from any one of methyl, isobutyl, tert-butyl, cyclohexyl or cyclopentyl.

[0043] Preferably, the compound has the structure shown in Formula II;

[0044]

[0045] The R1, R2, R3 and R4 have the same meanings as in Formula I.

[0046] The present invention further prefers that the compound has a structure shown in Formula II, that is, the substitution sites of R1, R2, R3 and R4 are preferred so that the para position of the cyano group does not contain a substituent. Such a structure is beneficial to reducing the interaction between the electron donating and electron sharing groups of the molecule, which is beneficial to the enhancement of the blue shift of luminescence and TADF properties, thereby helping to further improve the efficiency of the device and reduce the driving voltage.

[0047] Preferably, R1, R2, and R3 have the structure shown in formula (Hy-2); or

[0048] The R1, R2, and R4 have a structure represented by formula (Hy-2).

[0049] Preferably, R1, R2, and R3 have the structure shown in formula (Hy-2-1); or

[0050] The R1, R2, and R4 have the structure represented by formula (Hy-2-1).

[0051] Preferably, R1 and R3 have the structure shown in formula (Hy-2); or

[0052] The R2 and R4 have the structure represented by formula (Hy-2).

[0053] Preferably, R1 and R3 have the structure shown in formula (Hy-2-1); or

[0054] The R2 and R4 have the structure represented by formula (Hy-2-1).

[0055] Preferably, the Ra and Rb are each independently selected from a substituted or unsubstituted C1-C10 chain alkyl group or a substituted or unsubstituted C3-C10 cycloalkyl group.

[0056] The present invention further prefers that the substituents at the 3-position of the four carbazole groups can only be chain alkyl or cycloalkyl. Such structural alkyl or cycloalkyl is not easy to form a conjugated structure with carbazole, so it is beneficial to the blue shift of luminescence. At the same time, it does not contain highly active π electrons and is highly inert, which can protect the parent nucleus, thereby further improving the efficiency of the device and reducing the driving voltage.

[0057] Preferably, Ra and Rb are each independently selected from one of methyl, isopropyl, tert-butyl, cyclohexyl, phenyl or 4-tert-butylphenyl, preferably one of methyl, isopropyl, tert-butyl or cyclohexyl.

[0058] Preferably, the Rc is selected from methyl or tert-butyl.

[0059] The present invention preferably mono-substituted methyl or tert-butyl at the 3-position of the carbazole group. Compared with isobutyl, cyclohexyl and cyclopentyl, methyl and tert-butyl have stronger rigidity, can reduce the energy loss caused by molecular vibration and rotation, and are beneficial to improving the luminous efficiency of the material.

[0060] Preferably, said R5 is hydrogen.

[0061] Preferably, R1, R2, R3 and R4 each independently have a structure represented by formula (Hy-2) or formula (Hy-3), and at least one (eg, one, two, three or four) has a structure represented by formula (Hy-2).

[0062] The present invention further preferably has four carbazole groups that are all monosubstituted or unsubstituted with alkyl groups at the 3-position, and at least one of the alkyl groups at the 3-position is monosubstituted. Alkyl substitution at the 3-position can protect the carbazole active site, inhibit exciton quenching, and improve efficiency. At the same time, the absence of a substituent on the other side can improve the carrier transport performance of the molecule and reduce the voltage.

[0063] Preferably, R1, R2, R3 and R4 each independently have a structure shown in formula (Hy-2). When R1, R2, R3 and R4 each independently have a structure shown in formula (Hy-2), they may be completely the same structure or different structures, as long as they belong to formula (Hy-2).

[0064] Preferably, R1 and R3 have the same structure, and R2 and R4 have the same structure.

[0065] Preferably, R1, R2, R3 and R4 have the same structure.

[0066] Preferably, in formula (Hy-1), the X 1 ~X 6 In formula (Hy-2), 0 or 1 of them is N, and / or, in formula (Hy-2), the X 1 ~X7 0 or 1 of them is N, and / or, in formula (Hy-3), the X 1 ~X 8 There are 0 or 1 items in N.

[0067] Preferably, R1, R2, R3 and R4 are each independently selected from one of the following groups:

[0068]

[0069] More preferably,

[0070] More preferably,

[0071] The R1, R2, R3 and R4 are not selected from That is, at least one of the carbazoles is monosubstituted at the 3-position;

[0072] Among them, * represents the group has a connecting bond.

[0073] In the present invention, preferably R1, R2, R3 and R4 are selected from the above-mentioned specific groups, and cannot all be unsubstituted carbazoles. Alkyl substitution at the 3rd position can protect the active site of carbazole, inhibit exciton quenching, and improve efficiency. At the same time, the absence of a substituent on the other side can improve the carrier transport performance of the molecule and reduce the voltage.

[0074] Preferably, the compound has one of the structures shown in S1 to S81 below:

[0075]

[0076]

[0077]

[0078]

[0079] The second object of the present invention is to provide an application of the compound described in the first object, wherein the compound is applied to an organic electroluminescent device.

[0080] Preferably, the compound is used as a light-emitting layer material of an organic electroluminescent device, preferably a dye or a sensitizer of the light-emitting layer.

[0081] The third object of the present invention is to provide an organic electroluminescent device, comprising a first electrode, a second electrode and at least one organic layer inserted between the first electrode and the second electrode, wherein the organic layer contains at least one compound described in one of the objects.

[0082] Preferably, the organic layer comprises a light-emitting layer, and the light-emitting layer contains the compound described in one of the purposes;

[0083] Preferably, the compound serves as a dye or a sensitizer of the light-emitting layer.

[0084] The present invention also provides a display screen or a display panel, wherein the organic electroluminescent device as described above is used in the display screen or the display panel;

[0085] Preferably, the display screen or display panel is an OLED display.

[0086] The present invention also discloses an electronic device, wherein the electronic device has a display screen or a display panel, and the display screen or the display panel adopts the organic electroluminescent device as described above.

[0087] In a specific embodiment, the organic electroluminescent device includes a first electrode and a second electrode, and a plurality of organic material layers between the electrodes. The organic material layer can be divided into multiple regions. For example, the organic material layer can include a hole transport region, a light emitting layer, and an electron transport region.

[0088] In a specific embodiment, a substrate may be used below the first electrode or above the second electrode. The substrate is a glass or polymer material with excellent mechanical strength, thermal stability, water resistance, and transparency. In addition, a thin film transistor (TFT) may also be provided on the substrate used as a display.

[0089] The first electrode can be formed by sputtering or depositing the material used as the first electrode on the substrate. When the first electrode is used as an anode, an oxide transparent conductive material such as indium tin oxide (ITO), indium zinc oxide (IZO), tin dioxide (SnO2), zinc oxide (ZnO) and any combination thereof can be used. When the first electrode is used as a cathode, a metal or alloy such as magnesium (Mg), silver (Ag), aluminum (Al), aluminum-lithium (Al-Li), calcium (Ca), ytterbium (Yb), magnesium-indium (Mg-In), magnesium-silver (Mg-Ag) and any combination thereof can be used.

[0090] The organic material layer can be formed on the electrode by vacuum thermal evaporation, spin coating, printing, etc. The compound used as the organic material layer can be organic small molecules, organic macromolecules and polymers, and combinations thereof.

[0091] The hole transport region is located between the anode and the light-emitting layer. The hole transport region can be a hole transport layer (HTL) of a single-layer structure, including a single-layer hole transport layer containing only one compound and a single-layer hole transport layer containing multiple compounds. The hole transport region can also be a multi-layer structure including at least one layer of a hole injection layer (HIL), a hole transport layer (HTL), and an electron blocking layer (EBL).

[0092] The material of the hole transport region can be selected from, but not limited to, phthalocyanine derivatives such as CuPc, conductive polymers or polymers containing conductive dopants such as polyphenylene ethylene, polyaniline / dodecylbenzenesulfonic acid (Pani / DBSA), poly(3,4-ethylenedioxythiophene) / poly(4-styrenesulfonate) (PEDOT / PSS), polyaniline / camphorsulfonic acid (Pani / CSA), polyaniline / poly(4-styrenesulfonate) (Pani / PSS), aromatic amine derivatives (such as the compounds shown in HT-1 to HT-51 below); or any combination thereof.

[0093]

[0094]

[0095]

[0096]

[0097] The hole injection layer is located between the anode and the hole transport layer. The hole injection layer can be a single compound material or a combination of multiple compounds. For example, the hole injection layer can use one or more compounds of HT-1 to HT-51 above, or one or more compounds of HI1-HI3 below; or one or more compounds of HT-1 to HT-51 can be doped with one or more compounds of HI1-HI3 below.

[0098]

[0099] The light-emitting layer includes a light-emitting dye (i.e., dopant) that can emit different wavelength spectra, and may also include a host material (Host). The light-emitting layer can be a monochrome light-emitting layer that emits a single color such as red, green, and blue. A plurality of monochrome light-emitting layers of different colors can be arranged in a plane according to a pixel pattern, or they can be stacked together to form a color light-emitting layer. When light-emitting layers of different colors are stacked together, they can be separated from each other or connected to each other. The light-emitting layer can also be a single color light-emitting layer that can simultaneously emit different colors such as red, green, and blue.

[0100] According to different technologies, the light-emitting layer material can be made of different materials such as fluorescent electroluminescent materials, phosphorescent electroluminescent materials, and thermally activated delayed fluorescent materials. In an OLED device, a single light-emitting technology can be used, or a combination of multiple different light-emitting technologies can be used. These different light-emitting materials classified by technology can emit light of the same color or different colors.

[0101] In one aspect of the present invention, the light-emitting layer adopts the technology of thermally activated delayed fluorescence luminescence. The main material of the light-emitting layer is selected from, but not limited to, one or more combinations of the above PH-1 to PH-85.

[0102]

[0103]

[0104]

[0105]

[0106] The OLED organic material layer may further include an electron transport region between the light emitting layer and the cathode. The electron transport region may be a single-layer electron transport layer (ETL), including a single-layer electron transport layer containing only one compound and a single-layer electron transport layer containing multiple compounds. The electron transport region may also be a multilayer structure including at least one layer of an electron injection layer (EIL), an electron transport layer (ETL), and a hole blocking layer (HBL).

[0107] In one aspect of the present invention, the electron transport layer material can be selected from, but not limited to, one or more combinations of ET-1 to ET-73 listed below.

[0108]

[0109]

[0110]

[0111]

[0112] The device may further include an electron injection layer located between the electron transport layer and the cathode. Materials for the electron injection layer include, but are not limited to, one or more combinations of the following.

[0113] LiQ, LiF, NaCl, CsF, Li2O, Cs2CO3, BaO, Na, Li, Ca, Yb, Mg.

[0114] Compared with the prior art, the present invention has the following beneficial effects:

[0115] The compound provided by the present invention has benzonitrile as the parent core, substituted with four carbazole groups, and at least one of the carbazoles is substituted with a 3-alkyl monosubstituted (Hy-2). The compound can blue-shift the luminescence, and has a low degree of conjugation, so that the luminescence is bluer, and is suitable for deep blue light devices. In addition, while protecting the active sites of the compound, its carrier transport performance can be improved to a certain extent, thereby improving the luminescence efficiency of the device and reducing the voltage.

[0116] In addition, the intermolecular interactions of the compound provided by the present invention are relatively weak, and thus the sublimation temperature can be significantly reduced, which is beneficial to the evaporation of the device. DETAILED DESCRIPTION

[0117] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0118] The representative synthesis route of the compound represented by formula I provided by the present invention is as follows:

[0119]

[0120] Wherein, R1-R4 have the same meanings as in Formula I, and DMF is dimethylformamide.

[0121] The present invention will be described in detail below with reference to a number of specific embodiments. The compounds of the embodiments of the present invention can be synthesized with reference to the specific synthesis examples shown below, but it should be noted that obtaining the compound is not limited to the synthesis method and raw materials used in the present invention, and those skilled in the art can also select other methods or routes to obtain the novel compounds proposed in the present invention. The compounds for which the synthesis method is not mentioned in the present invention are raw materials obtained from commercial channels, or are prepared by these raw materials according to known methods.

[0122] The solvents and reagents used in the synthesis examples, such as ethanol, carbazole and other chemical reagents, can be purchased from the domestic chemical product market, such as Sinopharm Group Reagent Company, TCI Company, Shanghai Bid Pharmaceutical Company, Bailingwei Reagent Company, etc. In addition, those skilled in the art can also synthesize by known methods.

[0123] The analysis and detection of the intermediates and final products in the synthesis examples were carried out using an ABSCIEX mass spectrometer (4000QTRAP).

[0124] Synthesis Example 1: Synthesis of S2

[0125]

[0126] Synthesis of compound S2:

[0127] Add 3-tert-butylcarbazole (30.61 g, 137.08 mmol) and DMF (300 mL) to a 1000 mL three-necked flask. Under nitrogen protection, add sodium hydride (4.11 g, 171.34 mmol), stir for 1 hour, add 2,3,5,6-tetrafluorobenzonitrile, and stir for 2 hours. Pour the reaction solution into 500 mL of water, filter to obtain a yellow solid, and perform column chromatography on silica gel (petroleum ether PE: dichloromethane DCM = 10:1). Obtain 14.71 g of a yellow solid. The molecular ion mass determined by mass spectrometry is: 988.34 (theoretical value: 988.34).

[0128] Synthesis Example 2: Synthesis of S14

[0129]

[0130] Synthesis of intermediate S14-1:

[0131] Add 3-tert-butylcarbazole (22.96 g, 31.41 mmol) and DMF (200 mL) to a 500 mL three-necked flask. Under nitrogen protection, add sodium hydride (3.43 g, 142.79 mmol), stir for 1 hour, add 2,3,5,6-tetrafluorobenzonitrile (5 g, 28.56 mmol), and stir for 2 hours. Pour the reaction solution into 500 mL of water, filter to obtain a yellow solid, and perform column chromatography on silica gel (PE:DCM=10:1). Obtain 15.79 g of a yellow solid. The molecular ion mass determined by mass spectrometry is 785.01 (theoretical value: 785.02).

[0132] Synthesis of compound S14:

[0133] 3,6-diphenylcarbazole (3.83 g, 22.93 mmol), sodium hydride (0.92 g, 38.22 mmol), and DMF (80 mL) were added to a 250 mL three-necked flask, nitrogen was replaced, and the mixture was stirred for 1 hour. S14-1 (15 g, 19.11 mmol) was added and stirred for two hours. The reaction solution was poured into 300 mL of water and filtered to obtain a yellow solid. Silica gel mixed sample column chromatography (PE: DCM = 10: 1) was performed to obtain 8.94 g of a yellow solid. The molecular particle mass determined by mass spectrometry was 931.46 (theoretical value: 931.46).

[0134] Synthesis Example 3: Synthesis of S68

[0135]

[0136] Synthesis of intermediate S68-1:

[0137] Add 3-tert-butylcarbazole (15.31 g, 68.54 mmol) and DMF (200 mL) to a 500 mL three-necked flask. Under nitrogen protection, add sodium hydride (2.74 g, 114.23 mmol), stir for 1 hour, add 2,3,5,6-tetrafluorobenzonitrile (5 g, 28.56 mmol), and stir for 2 hours. Pour the reaction solution into 500 mL of water, filter to obtain a yellow solid, and perform column chromatography on silica gel (PE:DCM=10:1). Obtain 11.53 g of a yellow solid. The molecular ion mass determined by mass spectrometry is 581.70 (theoretical value: 581.71).

[0138] Synthesis of compound S68:

[0139] 3,6-diphenylcarbazole (13.18 g, 41.26 mmol), sodium hydride (1.65 g, 68.76 mmol), and DMF 80 mL were added to a 250 mL three-necked flask, nitrogen was replaced, and the mixture was stirred for 1 hour. S68-1 (10 g, 17.19 mmol) was added, and the mixture was stirred for two hours. The reaction solution was poured into 300 mL of water, and filtered to obtain a yellow solid. Silica gel sample was mixed and column chromatography (PE: DCM = 10: 1) was performed to obtain 12.78 g of a yellow solid. The molecular particle mass determined by mass spectrometry was 1080.51 (theoretical value: 1080.51).

[0140] Based on the same inventive concept, an embodiment of the present invention further provides an organic electronic light-emitting device comprising a compound of formula I. OLED is used as an organic electronic light-emitting device as an example of a device for illustration, but it should be understood that the following detailed description is not a limitation of the present invention, and those skilled in the art can extend the following detailed description to other organic electronic light-emitting devices.

[0141] Example 1

[0142] An OLED device is prepared as follows: In this embodiment, a glass plate coated with an ITO transparent conductive layer is ultrasonically treated in a commercial cleaning agent, rinsed in deionized water, ultrasonically degreased in an acetone:ethanol mixed solvent, baked in a clean environment until the water is completely removed, cleaned with ultraviolet light and ozone, and bombarded with a low-energy cation beam;

[0143] Place the glass substrate with the anode in a vacuum chamber and evacuate to a vacuum of <1×10 -5Pa, on the above anode layer film, vacuum thermal evaporation was performed in order of 10nm of HT-4:HI-3 (97 / 3, w / w) mixture as a hole injection layer, 60nm of compound HT-4 as a hole transport layer, 5nm of compound HT-51 as an electron blocking layer; 40nm of compound PH-54:S2 (100:40, w / w) binary mixture as a light-emitting layer; 5nm of PH-28 as a hole blocking layer, 25nm of compound ET-69:ET-57 (50 / 50, w / w) mixture as an electron transport layer, 1nm of LiF as an electron injection layer, and 150nm of metal aluminum as a cathode. The total evaporation rate of all organic layers and LiF was controlled at 0.1nm / sec, and the evaporation rate of the metal electrode was controlled at 1nm / sec.

[0144] The difference between Examples 2 to 12 and Comparative Examples 1 to 4 and Example 1 is that the dye S2 is replaced by other compounds, as shown in Table 3 for details.

[0145] The structure of the dye used in the comparative example is as follows:

[0146]

[0147] Among them, compounds C1 and C3 are detailed in patent application KR1020190067694A, compound C2 is detailed in patent application US20190292181A1, and compound C4 is detailed in patent application CN110759851A.

[0148] Performance Testing

[0149] (1) Theoretical calculation of the molecular excited state energy levels of the compounds in Table 1 is performed, where S1 is the singlet energy level and T1 is the singlet energy level. The calculation results are shown in Table 1.

[0150] Table 1

[0151] Compound No. S1 T1 C1 2.74 2.60 C2 2.63 2.56 C3 2.73 2.60 S1 2.78 2.62 S2 2.77 2.63 S5 2.81 2.64

[0152] As can be seen from the above table, from the theoretical calculation results, the luminescence of the compound of the present invention is blue-shifted compared to the comparative compound. Compared with C1, since the carbazole in the present invention is unilaterally substituted, the electron-donating property is weakened compared to the bilateral substitution, resulting in blue-shifted luminescence; compared with C2, since the present invention has only four carbazole derivatives as substituents, the number of electron-donating groups is reduced compared to C2, resulting in blue-shifted luminescence; for C3, since the carbazole of the present invention is alkyl-substituted, the degree of conjugation is reduced, resulting in bluer luminescence. Therefore, the compound provided by the present invention is suitable for deep blue light devices.

[0153] (2) The compounds in Table 2 were tested for molecular sublimation temperature. The test method was as follows:

[0154] The compound was purified using a biochemical purification device, and the corresponding temperature of the high temperature zone during sublimation was recorded.

[0155] The results are shown in Table 2.

[0156] Table 2

[0157]

[0158]

[0159] It can be seen from the above table that the sublimation temperature of the compound of the present invention is significantly lower than that of the comparative compound. This is because the compound of the present invention has an asymmetric alkyl-substituted carbazole substituent, which not only has a smaller molecular weight but also weakens the intermolecular interaction, thereby significantly reducing the sublimation temperature and facilitating device evaporation.

[0160] (3) The organic electroluminescent devices prepared in the examples and comparative examples were subjected to the following performance tests:

[0161] At the same brightness, the driving voltage and current efficiency of the organic electroluminescent device and the life of the device were measured using the PR 750 photoradiometer from Photo Research, the ST-86LA luminance meter (Beijing Normal University Photoelectric Instrument Factory) and the Keithley 4200 test system. Specifically, the voltage was increased at a rate of 0.1 V per second to measure the brightness of the organic electroluminescent device when it reached 1000 cd / m 2 The voltage at this time is the driving voltage, and the external quantum efficiency at this time is measured with an integrating sphere. The test results are shown in Table 3.

[0162] Table 3

[0163]

[0164] As can be seen from the above table, when the compound of the present invention is used as a dye, the voltage is reduced compared to the comparative example compounds C1 and C3, and excellent device performance is shown. This is because the compound of the present invention uses a unilateral alkyl-substituted carbazole, and compared with compound C1 (the difference from S4 is only the number of tert-butyl substitutions on carbazole), the carrier transport performance is stronger, and compared with compound C3 (the difference from S2 is only the type of substituents on carbazole), the transmission of electrons and holes is more balanced, so while protecting the active site of the compound, its carrier transport performance can be improved to a certain extent, thereby reducing the device voltage.

[0165] The only difference between the compound C4 used in Comparative Example 4 and S2 in Example 2 is that the tert-butyl group in S2 is replaced by an isopropyl group. The performance of the device in Comparative Example 4 is significantly worse than that in Example 2, which proves that the compound provided by the present invention can effectively improve the device performance compared with the isopropyl-substituted compound.

[0166] The present invention illustrates the detailed method of the present invention through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned detailed method, that is, it does not mean that the present invention must rely on the above-mentioned detailed method to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of various raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. An organic electroluminescent device, characterized in that: The organic electroluminescent device comprises a first electrode, a second electrode and at least one organic layer inserted between the first electrode and the second electrode, the organic layer comprises a light-emitting layer, and the dye in the light-emitting layer has a structure shown in Formula II; The R1, R2, R3 and R4 each independently have a structure represented by formula (Hy-1), formula (Hy-2) or formula (Hy-3), and at least one has a structure represented by formula (Hy-2); Wherein, * represents the connecting bond of the group; The X 1 ~X 6 Each independently selected from N or CR5, X 7 and X 8 are each independently selected from N or CH; In formula (Hy-1), the X 1 ~X 6 In formula (Hy-2), 0 or 1 of them is N. 1 ~X 7 In formula (Hy-3), 0 or 1 of them is N. 1 ~X 8 There are 0 or 1 items in N; Said R5 is hydrogen; The Ra and Rb are each independently selected from a substituted or unsubstituted C1-C10 chain alkyl group, a substituted or unsubstituted C3-C10 cycloalkyl group; The Rc is selected from any one of a methyl group, a substituted or unsubstituted C4-C18 chain alkyl group, and a substituted or unsubstituted C3-C20 cycloalkyl group; When the above groups have substituents, the substituents are selected from one or a combination of at least two of C1-C10 chain alkyl, C3-C10 cycloalkyl, and C1-C10 alkoxy.

2. The organic electroluminescent device according to claim 1, characterized in that: Said (Hy-2) has a structure shown in formula (Hy-2-1); The R C It has the same definition as claim 1.

3. The organic electroluminescent device according to claim 1 or 2, characterized in that: The Rc is selected from any one of methyl, isobutyl, tert-butyl, cyclohexyl or cyclopentyl.

4. The organic electroluminescent device according to claim 1, characterized in that: The R1, R2, and R3 have the structure shown in formula (Hy-2); or The R1, R2, and R4 have a structure represented by formula (Hy-2).

5. The organic electroluminescent device according to claim 1, characterized in that: The R1 and R3 have the structure shown in formula (Hy-2); or The R2 and R4 have the structure represented by formula (Hy-2).

6. The organic electroluminescent device according to claim 1, characterized in that: The Ra and Rb are each independently selected from one of methyl, isopropyl, tert-butyl and cyclohexyl.

7. The organic electroluminescent device according to claim 1, characterized in that: The Ra and Rb are each independently selected from one of methyl, isopropyl, tert-butyl or cyclohexyl.

8. The organic electroluminescent device according to claim 1, characterized in that: The Rc is selected from methyl or tert-butyl.

9. The organic electroluminescent device according to claim 1, characterized in that: The R1, R2, R3 and R4 each independently have a structure represented by formula (Hy-2) or formula (Hy-3), and at least one of them has a structure represented by formula (Hy-2).

10. The organic electroluminescent device according to claim 1, characterized in that: The R1, R2, R3 and R4 each independently have a structure represented by formula (Hy-2).

11. The organic electroluminescent device according to claim 1, characterized in that: The R1 and R3 have the same structure, and the R2 and R4 have the same structure.

12. The organic electroluminescent device according to claim 1, characterized in that: The structures of R1, R2, R3 and R4 are the same.

13. The organic electroluminescent device according to claim 1, characterized in that: The R1, R2, R3 and R4 are each independently selected from one of the following groups: The R1, R2, R3 and R4 are not selected from Among them, * represents the group has a connecting bond.

14. The organic electroluminescent device according to claim 13, characterized in that: The R1, R2, R3 and R4 are each independently selected from one of the following groups, 15. The organic electroluminescent device according to claim 14, characterized in that: The R1, R2, R3 and R4 are each independently selected from one of the following groups, 16. The organic electroluminescent device according to claim 1, characterized in that: The dye has one of the structures shown in S1 to S81 below:

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