1,3,4-triaryl-substituted dibenzofurans and light emitting devices thereof

Abstract

The present application belongs to the technical field of organic photoelectric material, and relates to 1,3,4-triaryl-substituted dibenzofuran compound and a light-emitting device thereof. Specifically, the compound of the present application is represented by the following general formula I, and has excellent film-forming property and thermal stability, and can be used as a host material of a light-emitting layer to prepare an organic electroluminescent device, especially a blue organic electroluminescent device. More importantly, the compound of the present application has excellent transport property and light-emitting property, when used as a blue light-emitting layer material, the voltage of a single-layer electroluminescent device and a stacked-layer electroluminescent device is effectively reduced, and the light-emitting efficiency and the life performance are improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of organic optoelectronic materials, and relates to 1,3,4-triaryl-substituted dibenzofuran compounds and light-emitting devices comprising the same. More particularly, the present application relates to 1,3,4-triaryl-substituted dibenzofuran compounds suitable for use in organic electroluminescent devices, in particular blue organic electroluminescent devices, and light-emitting devices using the same. BACKGROUND

[0002] An organic electroluminescent device has a series of advantages such as self-luminescence, low-voltage driving, full solidification, wide viewing angle, simple composition and process, and the like. Compared with a liquid crystal display, an organic electroluminescent device does not need a backlight. Therefore, the organic electroluminescent device has a wide application prospect.

[0003] An organic electroluminescent device generally comprises an anode, a metal cathode and an organic layer sandwiched therebetween. The organic layer mainly comprises a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, a hole blocking layer, an electron transport layer and an electron injection layer. In addition, the light-emitting layer mostly adopts a host-guest structure, that is, a light-emitting material (guest material) is doped in other materials (host material) at a certain concentration, so as to avoid concentration quenching caused by too high concentration of the doped material and three-triplet-state annihilation in a phosphorescent device system, and improve the light-emitting efficiency. Although phosphorescent and thermally activated delayed fluorescence (TADF) blue OLED materials based on triplet-state light-emitting mechanism have relatively high device efficiency, their lifetime performance still cannot meet the application requirements, and therefore the current blue OLED still adopts a fluorescent device system.

[0004] In the existing blue fluorescent device system, a blue host material generally adopts an aromatic heterocyclic compound having a specific condensed ring shape, mainly taking a dibenzofuran group and an anthracene group as a skeleton. This is because the anthracene group can utilize the annihilation effect (TTA) of electrons in the triplet state to improve the total amount of singlet excitons. Specifically, two triplet-state excitons annihilate each other to generate a ground-state electron and a singlet exciton, and then the generated singlet exciton transitions back to the ground state and emits fluorescence, thereby realizing a substantial improvement in the internal quantum efficiency of the fluorescent material, and the theoretical limit of the internal quantum efficiency can reach 62.5%.

[0005] In recent years, with the continuous improvement of blue light host materials with diphenylfuran and anthracene as the skeleton, although certain progress has been made in reducing operating voltage, improving device efficiency and prolonging operating life, there is still a continuing demand for long-life, low-voltage and high-efficiency blue light OLED light-emitting materials and devices with product upgrading. Around the blue light host materials with diphenylfuran and anthracene as the skeleton, some patent applications have disclosed related technical contents. Among them, JP2005314239A discloses anthracene monosubstituted diphenylfuran compounds 7 and anthracene and phenyl disubstituted diphenylfuran compounds 17, but the voltage of these compounds as blue light host materials in the device is generally high (more than 5.3V), and the lifetime performance needs to be improved; CN109804043A, CN109790462A, CN111933810A, CN106356468A, CN107531661A, CN113582955A and KR1020220081059A each discloses a series of triaryl-substituted diphenylfuran compounds (aryl substitution sites are the same as each other), and obvious improvement in device voltage is achieved, but unfortunately, these patent applications do not involve the relationship between different aryl substitution sites and device performance, but the difference between triaryl-substituted diphenylfuran compounds based on different substitution sites in device performance (especially in voltage, efficiency and lifetime) is large, so it is necessary to carry out relevant research. In addition, the three aryl groups in the above diphenylfuran compounds are not substituted on the same benzene ring, which makes the technical blank still exist in the field. SUMMARY

[0006] Problem to be solved by the invention

[0007] In view of the above problems existing in the prior art, the present application provides a series of novel 1,3,4-triaryl-substituted diphenylfuran compounds and their light-emitting devices. The compounds of the present application have high thermal stability and high chemical stability due to their own rigid skeleton structure, and finally are applied to light-emitting devices, improving the service life of the device. The three different substitution groups utilize the steric hindrance between each other to further improve the stability and light-emitting efficiency of the device, and reduce the driving voltage of the device.

[0008] Solution for solving the problem

[0009] For the triaryl-substituted dibenzofurans disclosed in the prior art, the three substitution sites are not on the same benzene ring, while the present application introduces aryl groups such as anthracene group at positions 1, 3 and 4 of the dibenzofuran structure as the connection sites. The 1, 3, 4-trisubstitution mode utilizes the steric hindrance between adjacent positions to achieve a highly stereospecific molecular conformation of the triaryl-substituted dibenzofurans, maximally utilizes the steric hindrance effect and maintains the electronic and photophysical properties of the dibenzofuran structure. Such connection mode is particularly suitable for constructing blue host materials, and can obtain host molecules with steric hindrance structure, which can improve the molecular arrangement and prevent the aggregation effect, thereby ensuring the carrier mobility and avoiding the reduction of quantum efficiency caused by aggregation. In addition, the 1, 3, 4-trisubstitution mode of the three substituents on one benzene ring can form a relatively concentrated π-electron conjugated system, which is beneficial to the electron transport and the reduction of voltage, and ultimately improves the light-emitting device.

[0010] That is, the scheme of the present application is shown in the technical scheme as described above.

[0011] Effects of the invention

[0012] The 1, 3, 4-triaryl-substituted dibenzofurans of the present application have a highly stereospecific rigid structure, good film-forming property and thermal stability. Benefiting from the absence of introduction of additional steric hindrance groups, such dibenzofurans are very suitable for preparing various light-emitting devices, especially blue organic electroluminescent devices. The light-emitting device prepared from the dibenzofurans exhibits the advantages of low driving voltage, high luminous efficiency and long device lifetime. The specific effects are described as follows:

[0013] The 1, 3, 4-triaryl-substituted dibenzofurans of the present application have adjustable carrier transport performance, adjustable HOMO and LUMO energy levels and suitable singlet and triplet energy levels, and are suitable as the constituting material of the light-emitting layer in the organic electroluminescent device, especially as the host material. The light-emitting device prepared from such material, especially the blue organic electroluminescent device, exhibits the advantages of low driving voltage, high luminous efficiency and long device lifetime, which is significantly superior to the existing organic electroluminescent device.

[0014] In addition, the preparation method of the 1, 3, 4-triaryl-substituted dibenzofurans of the present application is simple, and the raw materials are easy to obtain, which can meet the development needs of industrial scale production. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 The preparation method of the compound I-1 in Example 1 of the present application is as follows: 1 H-NMR spectrum.

[0016] Figure 2 H-NMR spectrum of Compound I-5 in Example 3 of the present invention 1 H-NMR spectrum.

[0017] Figure 3 H-NMR spectrum of Compound I-4 in Example 2 of the present invention 1 H-NMR spectrum.

[0018] Figure 4 Organic electroluminescence spectra of organic EL devices 2, 8, 12 and 23 in Example 29, Example 35, Example 39 and Example 50 of the present invention.

[0019] Figure 5 Device luminance-lumen efficiency curve of organic EL device 44 in Example 71 of the present invention.

[0020] Figure 6 Device luminance-Blue index curve of organic EL device 44 in Example 71 of the present invention.

[0021] Figure 7 Configuration diagram of organic EL devices in Examples 1 to 27 and Comparative Examples 1 to 7 of the present invention, which does not contain Layer 7 (i.e., hole blocking layer) in actual layered structure of the device.

[0022] Explanation of reference signs

[0023] 1 substrate; 2 anode; 3 hole injection layer; 4 hole transport layer; 5 electron blocking layer; 6 light emitting layer; 7 hole blocking layer; 8 electron transport layer; 9 electron injection layer; 10 cathode DETAILED DESCRIPTION

[0024] Hereinafter, the embodiments of the present invention will be described in detail. However, the present invention is not limited by the following embodiments.

[0025] <1,3,4-triaryl-substituted dibenzofurans>

[0026] The 1,3,4-triaryl-substituted dibenzofurans of the present invention can be represented by the following general formula I,

[0027]

[0028] wherein,

[0029] Ar1, Ar2and Ar3each independently represent any one of the following groups optionally substituted with one or more deuterium atoms: phenyl, naphthyl, biphenyl and phenyl-substituted naphthyl;

[0030] each R 1 each independently represents a hydrogen atom or a deuterium atom.

[0031] Preferably, in General Formula I, Ar1, Ar2and Ar3each independently represent any one of the following groups:

[0032]

[0033] wherein,

[0034] the dotted line represents a binding bond;

[0035] each R 2 each independently represents a hydrogen atom or a deuterium atom, preferably a deuterium atom. More preferably, in General Formula I, Ar1represents any one of the following groups:

[0036]

[0037] and, Ar2and Ar3each independently represent any one of the following groups:

[0038]

[0039] wherein,

[0040] the dotted line represents a binding bond;

[0041] each R 2 each independently represents a hydrogen atom or a deuterium atom, preferably a deuterium atom.

[0042] Preferably, the 1,3,4-triaryl-substituted dibenzofurans of the present application can be represented by the following General Formula I’,

[0043]

[0044] wherein,

[0045] each R 1 each independently represents a hydrogen atom or a deuterium atom, preferably a deuterium atom;

[0046] Ar1, Ar2and Ar3are as defined in General Formula I.

[0047] In one embodiment, the 1,3,4-triaryl-substituted dibenzofurans of the present application can be represented by the following General Formula I-1, preferably by the following General Formula I’-1,

[0048]

[0049] wherein,

[0050] each R 1 each independently represents a hydrogen atom or a deuterium atom, preferably a deuterium atom;

[0051] each R 2 each independently represents a hydrogen atom, a deuterium atom, a phenyl group or a phenyl group substituted with one or more deuterium atoms, and at most one of the five R 2 each R 2 each independently represents a deuterium atom or a penta-deuterated phenyl group, and at most one of the five R 2 each R

[0052] Ar1is as defined in general formula I.

[0053] In one embodiment, the 1,3,4-triaryl-substituted dibenzofurans of the present application can be represented by the following general formula I-2, preferably by the following general formula I'-2,

[0054]

[0055] wherein,

[0056] each R 1 each independently represents a hydrogen atom or a deuterium atom, preferably a deuterium atom;

[0057] each R 2 each independently represents a hydrogen atom or a deuterium atom, preferably a deuterium atom;

[0058] Ar1is as defined in general formula I.

[0059] In one embodiment, the 1,3,4-triaryl-substituted dibenzofurans of the present application can be represented by the following general formula I-3, preferably by the following general formula I'-3,

[0060]

[0061] wherein,

[0062] each R 1 each independently represents a hydrogen atom or a deuterium atom, preferably a deuterium atom;

[0063] each R 2 each independently represents a hydrogen atom or a deuterium atom, preferably a deuterium atom;

[0064] Ar1is as defined in general formula I.

[0065] In particular, the 1,3,4-triaryl-substituted dibenzofurans of the present application can be selected from any one of the following compounds:

[0066]

[0067]

[0068]

[0069]

[0070]

[0071]

[0072]

[0073]

[0074] <Organic electroluminescent device>

[0075] The organic electroluminescent device of the present application includes a first electrode, a second electrode provided opposite to the first electrode, and at least one organic layer sandwiched between the first electrode and the second electrode, wherein the at least one organic layer contains the 1,3,4-triaryl-substituted dibenzofuran compound of the present application.

[0076] In one embodiment, as shown in Figure 7 The organic electroluminescent device of the present application is obtained by sequentially disposing each layer (e.g., anode 2, hole injection layer 3, hole transport layer 4, electron blocking layer 5, light emitting layer 6, hole blocking layer 7, electron transport layer 8, electron injection layer 9, and cathode 10) on a substrate 1.

[0077] The organic electroluminescent device of the present application is not limited to such a structure, and for example, one or some of the organic layers can be omitted in the multilayer structure. For example, the hole blocking layer 7 between the light emitting layer 6 and the electron transport layer 8 can be omitted, and the anode 2, hole injection layer 3, hole transport layer 4, electron blocking layer 5, light emitting layer 6, electron transport layer 8, electron injection layer 9, and cathode 10 are sequentially disposed on the substrate 1, or the hole injection layer 3 between the anode 2 and the hole transport layer 4, the hole blocking layer 7 between the light emitting layer 6 and the electron transport layer 8, and the electron injection layer 9 between the electron transport layer 8 and the cathode 10 can be omitted at the same time, and the anode 2, hole transport layer 4, electron blocking layer 5, light emitting layer 6, electron transport layer 8, and cathode 10 are sequentially disposed on the substrate 1, and finally the corresponding organic electroluminescent device is obtained.

[0078] The organic electroluminescent device of the present application can be manufactured by materials and methods known in the technical field, except that the organic layer (e.g., the light-emitting layer 6) described above contains the compound of the present application (e.g., as a host material in the light-emitting layer 6). In addition, in the case where the organic electroluminescent device described above contains a plurality of organic layers, the organic layers described above can be formed of the same or different substances. For example, the organic electroluminescent device according to the present application can be manufactured by sequentially stacking a first electrode, an organic layer, and a second electrode on a substrate. At this time, it can be manufactured by forming an anode by evaporating a metal or a metal oxide having conductivity or an alloy thereof on a substrate using a PVD (physical vapor deposition) method such as a sputtering method or an electron beam evaporation method, and then forming an organic layer containing a hole-injection layer, a hole-transport layer, a light-emitting layer, and an electron-transport layer on the anode, and thereafter evaporating a substance that can be used as a cathode on the organic layer. However, the manufacturing method is not limited thereto. As one example, the first electrode described above is an anode, and the second electrode described above is a cathode, or the first electrode described above is a cathode, and the second electrode described above is an anode.

[0079] As the anode of the organic electroluminescent device of the present application, a known electrode material can be used. For example, an electrode material having a large work function, such as a metal or an alloy thereof, such as vanadium, chromium, copper, zinc, gold, and the like; a metal oxide, such as zinc oxide, indium oxide, indium tin oxide (ITO), indium zinc oxide (IZO), and the like; a combination of a metal and an oxide, such as ZnO:Al or SnO2:Sb; a conductive polymer, such as poly(3-methylthiophene), poly[3,4-(ethylene-1,2-dioxy)thiophene] (PEDOT), polypyrrole, polyaniline, and the like, is used. Among these, ITO is preferred.

[0080] As the hole-injection layer of the organic electroluminescent device of the present application, a known material having a hole-injection property can be used. For example, a porphyrin compound typified by copper phthalocyanine, a naphthalene diamine compound, a star-shaped triphenylamine compound, a triphenylamine trimer and a tetramer having a structure in which three or more triphenylamine structures are linked by a single bond or a divalent group not containing a hetero atom in a molecule, an acceptor-type dibenzofuran compound such as hexacyanobenzophenanthroline, and a coating-type polymer material. These materials can be formed into a thin film by an evaporation method, and a known method such as a spin coating method, an inkjet method, and the like.

[0081] As the hole-transporting layer of the organic electroluminescent device of the present application, a publicly known material having a hole-transporting property can be used. In addition to this, a publicly known other material having a hole-transporting property can also be used. For example, a compound containing a m-carbazolylphenyl group; an aniline derivative such as N,N'-diphenyl-N,N'-di(m-tolyl)aniline (TPD), N,N'-diphenyl-N,N'-(1-naphthyl)-1,1'-biphenyl-4,4'-diamine (NPB), N,N,N',N'-tetraphenylbenzidine, and the like; 1,1-bis[(di-4-tolylamino)phenyl]cyclohexane (TAPC); various triphenylamine trimers and tetramers; 9,9',9"-triphenyl-9H,9'H,9"H-3,3':6',3"-tris-carbazole (Tris-PCz), and the like. They can be used in the form of a single layer formed by film formation alone or by film formation in admixture with other materials, and also in the form of a stacked structure of layers formed by film formation alone, a stacked structure of layers formed by film formation in admixture, or a stacked structure of layers formed by film formation alone and layers formed by film formation in admixture. These materials can be formed into thin films by an evaporation method, and also by a publicly known method such as a spin coating method, an inkjet method, and the like.

[0082] In addition, in the hole-injecting layer or the hole-transporting layer, a substance further P-doped with aniline hexachloroantimonate, an axeridine derivative, or the like, which is a material usually used in the layer, a high molecular compound having the structure of an aniline derivative such as TPD in a partial structure thereof, and the like can also be used.

[0083] As the electron-transporting layer of the organic electroluminescent device of the present application, a publicly known material having an electron-transporting property can be used. In addition to this, a publicly known other material having an electron-transporting property can also be used. For example, a carbazole derivative such as 4,4',4"-tris(N-carbazolyl)triphenylamine (TCTA), 9,9-bis[4-(carbazol-9-yl)phenyl]fluorene, 1,3-bis(carbazol-9-yl)benzene (mCP), 2,2-bis(4-carbazol-9-ylphenyl)adamantane (Ad-Cz), and the like; a compound having a triphenylsilyl group and a triarylamine structure represented by 9-[4-(carbazol-9-yl)phenyl]-9-[4-(triphenylsilyl)phenyl]-9H-fluorene; a monoamine compound having a high electron-blocking property, various triphenylamine dimers, and the like. They can be used in the form of a single layer formed by film formation alone or by film formation in admixture with other materials, and also in the form of a stacked structure of layers formed by film formation alone, a stacked structure of layers formed by film formation in admixture, or a stacked structure of layers formed by film formation alone and layers formed by film formation in admixture. These materials can be formed into thin films by an evaporation method, and also by a publicly known method such as a spin coating method, an inkjet method, and the like.

[0084] As the light-emitting layer of the organic electroluminescent device of the present application, the 1,3,4-triaryl-substituted dibenzofuran compound of the present application is preferably contained. In addition to this, various metal complexes such as metal complexes of hydroxyquinoline derivatives including Alq3, compounds having a pyrimidine ring structure, anthracene derivatives, distyrylbenzene derivatives, pyrene derivatives, oxazole derivatives, poly-p-phenylenevinylene derivatives, and the like can also be used.

[0085] The light-emitting layer can be composed of a host material and a dopant material. As the host material, the 1,3,4-triaryl-substituted dibenzofuran compound of the present application is preferably contained. In addition to this, mCBP, mCP, thiazole derivatives, benzimidazole derivatives, polydialkylfluorene derivatives, dibenzofuran compounds having a partial structure of an indole ring as a condensed ring, and the like can also be used. As the dopant material, the dibenzofuran derivative of the present application is preferably contained. In addition to this, aromatic amine derivatives, styrylamine compounds, boron complexes, fluoranthene compounds, metal complexes, and the like can also be used. For example, pyrene derivatives, anthracene derivatives, quinacridone, coumarin, rubrene, perylene and derivatives thereof, benzopyran derivatives, rhodamine derivatives, aminostyryl derivatives, spirobifluorene derivatives, and the like can be exemplified. They can be used in a form of a single layer in which they are deposited alone or in which they are mixed with other materials, and can be formed in a stacked structure of layers in which layers deposited alone are stacked with each other, a stacked structure of layers in which layers mixed are stacked with each other, or a stacked structure of layers in which layers deposited alone are stacked with layers mixed. These materials can be formed into thin films by an evaporation method, and known methods such as a spin coating method, an inkjet method, and the like.

[0086] As the hole-blocking layer of the organic electroluminescent device of the present application, known materials having a hole-blocking property can be used. In addition to this, other compounds having a hole-blocking property can also be used to form. For example, 2,4,6-tris(3-phenyl)-1,3,5-triazine (T2T), 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene (TPBi), bathocuproin (BCP), phenanthroline derivatives such as bathocuproin (BCP), metal complexes of quinol alcohol derivatives such as aluminum (III) bis(2-methyl-8-hydroxyquinoline)-4-phenylphenoxide (BAlq), and various rare earth complexes, oxazole derivatives, triazole derivatives, triazine derivatives, and the like having a hole-blocking action. They can be used in a form of a single layer in which they are deposited alone or in which they are mixed with other materials, and can be formed in a stacked structure of layers in which layers deposited alone are stacked with each other, a stacked structure of layers in which layers mixed are stacked with each other, or a stacked structure of layers in which layers deposited alone are stacked with layers mixed. These materials can be formed into thin films by an evaporation method, and known methods such as a spin coating method, an inkjet method, and the like.

[0087] The hole-blocking material described above can also be used to form the electron transport layer described below. That is, by using the aforementioned known hole-blocking material, a layer that simultaneously serves as a hole-blocking layer and an electron transport layer can be formed.

[0088] As the electron transport layer of the organic electroluminescent device of the present invention, materials with known electron transport properties can be used. In addition, other compounds with electron transport properties can also be used. Examples include metal complexes of hydroxyquinoline derivatives, primarily Alq3 and BAlq; various metal complexes; triazole derivatives; triazine derivatives; oxadiazole derivatives; pyridine derivatives; bis(10-hydroxybenzo[H]quinoline)beryllium (Be(bq)2); benzimidazole derivatives such as 2-[4-(9,10-dinaphthyl-2-anthracene-2-yl)phenyl]-1-phenyl-1H-benzimidazole (ETL); thiadiazole derivatives; anthracene derivatives; carbodiimide derivatives; quinoxaline derivatives; pyridoindole derivatives; phenanthroline derivatives; thiarroline derivatives, etc. They can be used individually as films, or as monolayers formed by mixing with other materials. They can also be used to form stacked structures of individually formed layers, stacked structures of mixed layers, or stacked structures of individually formed layers and mixed layers. These materials can be formed into thin films using known methods such as vapor deposition, spin coating, and inkjet printing.

[0089] As the electron injection layer of the organic electroluminescent device of the present invention, it can be formed using materials known in themselves. For example, alkali metal salts such as lithium fluoride and cesium fluoride; alkaline earth metal salts such as magnesium fluoride; metal complexes of hydroxyquinoline derivatives such as lithium hydroxyquinoline; metal oxides such as aluminum oxide, etc.

[0090] In the electron transport layer or electron injection layer, materials commonly used in this layer can be further doped with metals such as cesium or triarylphosphine oxide derivatives.

[0091] As the cathode of the organic electroluminescent device of the present invention, it is preferable to use an electrode material with a low work function (such as aluminum or magnesium) or an alloy with a low work function (such as magnesium-silver alloy, magnesium-indium alloy, or aluminum-magnesium alloy) as the electrode material.

[0092] As the substrate for this invention, conventional substrates used in organic light-emitting devices, such as glass or plastic, can be used. In this invention, a glass substrate is selected.

[0093] The following examples illustrate the manufacture of the compounds of the present invention and organic electroluminescent devices comprising them. However, the following examples are merely illustrative of the invention, and the scope of the invention is not limited thereto. Unless otherwise stated, the reagents, materials, and instruments used in the following examples are all available through conventional commercial means.

[0094] Example 1: Synthesis of compound I-1

[0095] [Synthesis of compound M1]

[0096] The synthetic route of compound M1 is shown as follows:

[0097]

[0098] Into a clean 250 mL three-necked flask, compound A, dibenzo[b,d]furan-4-ol (5 g), 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) (0.2 g) and super dry dichloromethane (DCM) (20 mL) were added successively under nitrogen atmosphere. Triisopropylsilyl chloride (TIPSCl) (6.3 g) was added dropwise under ice-water bath condition. After stirring for 0.5 h, the system was gradually warmed to room temperature and reacted overnight under reflux condition. After completion of the reaction, the reaction solution was poured into water (about 100 mL) and extracted with DCM. The organic phase was dried over anhydrous sodium sulfate, concentrated under reduced pressure and purified by column chromatography (stationary phase: 350 mesh silica gel, eluent: petroleum ether (PE): DCM = 5:1, V / V) to give the product (8.9 g, yield 96%) which was compound M1. MS (EI): m / z 340.12 [M + ].

[0099] [Synthesis of compound M2]

[0100] The synthetic route of compound M2 is shown as follows:

[0101]

[0102] Into a clean 100 mL single-necked flask, compound M1 (8.9 g) and DCM (50 mL) were added successively under nitrogen atmosphere. Subsequently, N-bromosuccinimide (NBS) (2.3 g) was added under ice-water bath condition. After half an hour, NBS (2.35 g) was added again. After completion of the reaction, the system was warmed to room temperature and reacted for 6 h. After completion of the reaction, water was added, the organic phase was concentrated and purified by column chromatography (stationary phase: 350 mesh silica gel, eluent: PE: DCM = 5:1, V / V) to give the product (10 g, yield 91%) which was compound M2. MS (EI): m / z 419.40 [M + ].

[0103] [Synthesis of compound M3]

[0104] The synthetic route of compound M3 is shown as follows:

[0105]

[0106] To a 100 mL three-necked flask, compound M2 (10 g), (10-phenylanthracen-9-yl)boronic acid (7.8 g) as compound B, tetrakis(triphenylphosphine)palladium (1.4 g) and potassium carbonate (3 g) were added under nitrogen atmosphere, and a mixed solvent of 1,4-dioxane and water (100 mL, 1,4-dioxane:water = 5:1, V / V) was stirred and dissolved, and then the temperature was raised to 100°C. After the reaction was completed, the organic phase was separated and concentrated, and then ethanol was added to obtain a solid product (12 g, yield 84%), which was compound M3. MS (EI): m / z 592.88 [M + ]。

[0107] [Synthesis of compound M4]

[0108] The synthetic route of compound M4 is shown below:

[0109]

[0110] Under nitrogen atmosphere, compound M3 (10 g) and tetra-n-butylammonium fluoride (TBAF) (8.8 g) were transferred to a 250 mL three-necked flask, and then tetrahydrofuran (THF) (150 mL) was added, stirred and dissolved, and then cooled with an ice water bath. After the reaction was completed, water was added, the organic phase was separated and concentrated to obtain a solid product (7 g, yield 95%), which was compound M4. MS (EI): m / z 436.18 [M + ]。

[0111] [Synthesis of compound M5]

[0112] The synthetic route of compound M5 is shown below:

[0113]

[0114] Under nitrogen atmosphere, compound M4 (7 g) and acetic acid (AcOH) (100 mL) were sequentially added to a clean 250 mL three-necked flask. The system was gradually cooled to 0°C, and then liquid bromine (2.7 g) was added dropwise to the reaction system, and then refluxed for 3 h. After the reaction was completed, the heating was stopped, and then the reaction liquid was cooled to room temperature. The reaction liquid was poured into an aqueous sodium bisulfite solution, extracted with DCM, and then the organic phase was dried with anhydrous sodium sulfate, concentrated to obtain a solid product (7.9 g, yield 96%), which was compound M5. MS (EI): m / z 515.43 [M + ]。

[0115] [Synthesis of compound M6]

[0116] The synthetic route of compound M6 is shown below:

[0117]

[0118] Into a clean 250 mL three-necked flask, compound M5 (7.6 g), triethylamine (TEA) (4.2 g) and super dry DCM (100 mL) were sequentially added under nitrogen atmosphere. The system was cooled to 0 °C, triflic anhydride (Tf20) (5 g) was added, then gradually warmed to room temperature, and reacted for 5 h. After the reaction was completed, the reaction solution was poured into water (about 200 mL), extracted with DCM, and the organic phase was dried over anhydrous sodium sulfate, concentrated, and purified by column chromatography (stationary phase: 350 mesh silica gel, eluent: PE:DCM = 5:1, V / V) to obtain a solid product (8.0 g, yield 84%), which was compound M6. MS (EI): m / z 647.34 [M + ]。

[0119] [Synthesis of compound I-1]

[0120] The synthesis route of compound I-1 is as follows:

[0121]

[0122] Into a clean 250 mL three-necked flask, compound M5 (7.6 g), triethylamine (TEA) (4.2 g) and super dry DCM (100 mL) were sequentially added under nitrogen atmosphere. The system was cooled to 0 °C, triflic anhydride (Tf20) (5 g) was added, then gradually warmed to room temperature, and reacted for 5 h. After the reaction was completed, the reaction solution was poured into water (about 200 mL), extracted with DCM, and the organic phase was dried over anhydrous sodium sulfate, concentrated, and purified by column chromatography (stationary phase: 350 mesh silica gel, eluent: PE:DCM = 5:1, V / V) to obtain a solid product (8.0 g, yield 84%), which was compound M6. MS (EI): m / z 647.34 [M + ]。

[0123] Example 2-27: Synthesis of specific compounds of the present application

[0124] Referring to the synthesis route of compound I-1 in Example 1, and selecting the corresponding compound A, compound B and compound C, a series of specific compounds of the present application were prepared (see Table 1).

[0125] Table 1

[0126]

[0127]

[0128]

[0129] Example 28: Preparation of a single-layer organic electroluminescent device 1 (organic EL device 1)

[0130] A hole injection layer 3, a hole transport layer 4, an electron blocking layer 5, a light emitting layer 6, an electron transport layer 8, an electron injection layer 9, and a cathode 10 were formed in this order on the transparent anode 2 (which was previously formed on the glass substrate 1) to prepare an organic electroluminescent device as shown in FIG. 1 (but not containing the hole blocking layer 7). Figure 4

[0131] Specifically, a glass substrate on which an ITO electrode having a film thickness of 100 nm was formed was subjected to ultrasonic treatment in a Decon 90 alkaline cleaning solution, rinsing in deionized water, cleaning in acetone and ethanol each three times, baking in a clean environment until moisture was completely removed, cleaning with ultraviolet light and ozone, and surface bombardment with a low-energy cation beam. The glass substrate with the ITO electrode was placed in a vacuum chamber, vacuumed to 4 x 10 -4 -2 x 10 -5 Pa. On the above ITO anode, 97 wt% HIL / 3 wt% HTL was vapor-deposited to form a layer having a film thickness of 10 nm as a hole injection layer. On the above hole injection layer, HTL was vapor-deposited to form a layer having a film thickness of 20 nm as a hole transport layer. On the above hole transport layer, EBL was vapor-deposited to form a layer having a film thickness of 10 nm as an electron blocking layer. On the above electron blocking layer, a compound I-1 in Example 1 as a host material and BD1 as a dopant material were co-vapor-deposited from two sources to form a layer having a film thickness of 25 nm as a light emitting layer, the dopant weight ratio of BD1 being 3 wt%. On the above light emitting layer, 50 wt% ETL / 50 wt% Liq was vapor-deposited to form a layer having a film thickness of 30 nm as an electron transport layer. On the above electron transport layer, Yb was vapor-deposited to form a layer having a film thickness of 1 nm as an electron injection layer. On the above electron injection layer, a 90 wt% Mg / 10 wt% Ag electrode was vapor-deposited to a thickness of 15 nm, and finally, on the above Mg:Ag cathode, CPL was vapor-deposited to form a layer having a film thickness of 65 nm as a capping layer, thereby obtaining the organic EL device 1.

[0132] Examples 29-54: Preparation of single-layer organic EL devices 2-27

[0133] The preparation conditions of the organic EL device 1 in Reference Example 28 were referred to, and the compounds corresponding to each layer structure in Table 2 were used to prepare the organic EL devices 2-27, respectively.

[0134] Comparative Examples 1-7: Preparation of single-layer organic EL devices Comparative Examples 1-7

[0135] ​An organic EL device Comparative Example 1 was produced in the same manner as in Reference Example 28, except that the compound corresponding to each layer structure in Table 2 was used.

[0136] Table 2

[0137]

[0138] Example 55: Production of a stacked organic electroluminescence device 28 (organic EL device 28)

[0139] A glass substrate on which an ITO electrode having a film thickness of 100 nm was formed was subjected to ultrasonic treatment in Decon 90 alkaline cleaning solution, rinsed in ionized water, cleaned three times each in acetone and ethanol, baked in a clean atmosphere until moisture was completely removed, cleaned with ultraviolet light and ozone, and the surface was subjected to low-energy cation beam bombardment. The glass substrate with the ITO electrode was placed in a vacuum chamber, vacuum-pumped to 4 x 10 -4 -2 x 10 -5Pa. On the above ITO anode, 97 wt% HIL / 3 wt% HTL was evaporated to form a layer having a thickness of 10 nm as a hole injection layer (denoted as hole injection layer 1). On the above hole injection layer, HTL was evaporated to form a layer having a thickness of 20 nm as a hole transport layer (denoted as hole transport layer 1). On the above hole transport layer, EBL was evaporated to form a layer having a thickness of 10 nm as an electron blocking layer (denoted as electron blocking layer 1). On the above electron blocking layer, compound I-1 in Example 1 as a host material and BD1 as a dopant material were co-evaporated to form a layer having a thickness of 25 nm as an emission layer (denoted as emission layer 1), the doping weight ratio of BD1 being 3 wt%. On the above emission layer, 50 wt% ETL / 50 wt% Liq was evaporated to form a layer having a thickness of 30 nm as an electron transport layer (denoted as electron transport layer 1). On the above electron transport layer, 50 wt% ETL / 50 wt% Yb was evaporated to form a layer having a thickness of 30 nm as a connecting layer. On the connecting layer, an Ag electrode was evaporated to a thickness of 15 nm, and then, on the above Ag electrode, 97 wt% HIL / 3 wt% HTL was evaporated to form a layer having a thickness of 10 nm as a hole injection layer (denoted as hole injection layer 2). On the above hole injection layer, HTL was evaporated to form a layer having a thickness of 20 nm as a hole transport layer (denoted as hole transport layer 2). On the above hole transport layer, EBL was evaporated to form a layer having a thickness of 10 nm as an electron blocking layer (denoted as electron blocking layer 2). On the above electron blocking layer, compound I-1 in Example 1 as a host material and BD1 as a dopant material were co-evaporated to form a layer having a thickness of 25 nm as an emission layer (denoted as emission layer 2), the doping weight ratio of BD1 being 3 wt%. On the above emission layer, 50 wt% ETL / 50 wt% Liq was evaporated to form a layer having a thickness of 30 nm as an electron transport layer (denoted as electron transport layer 2). On the above electron transport layer, Yb was evaporated to form a layer having a thickness of 1 nm as an electron injection layer. On the above electron injection layer, a 90 wt% Mg / 10 wt% Ag electrode was evaporated to a thickness of 15 nm, and finally, on the above Mg:Ag cathode, CPL was evaporated to form a layer having a thickness of 65 nm as a capping layer, thus obtaining an organic EL device 28.

[0140] Examples 56-81: Preparation of stacked organic EL devices 29-54

[0141] The preparation conditions of the organic EL device 28 in Reference Example 55 were referred to, and using the compounds corresponding to the layer structures in Table 3, respectively, organic EL devices 29-54 were prepared.

[0142] Comparative Examples 8-14: Preparation of stacked organic EL devices Comparative Examples 8-14

[0143] The organic EL devices Comparative Examples 8 to 14 were prepared in the same manner as in Reference Example 55, using the compounds corresponding to each layer structure in Table 3.

[0144] Table 3

[0145]

[0146]

[0147] The organic EL devices in Tables 2 and 3 used different types of 1,3,4-triaryl- substituted dibenzofurans as the blue host material in the light-emitting layer, together with the blue guest material BD1, while the organic EL devices Comparative Examples used anthracenyl mono-substituted dibenzofurans BH1, anthracenyl and phenyl di-substituted dibenzofurans BH2, and anthracenyl and phenyl (or methoxy) tri-substituted dibenzofurans BH3 to BH7 as the blue host material in the light-emitting layer, together with the same blue guest.

[0148] The structures of the compounds involved in the organic EL devices and the organic EL devices Comparative Examples are as follows:

[0149]

[0150] The light-emitting properties of the organic EL devices 1 to 54 prepared in Examples 28 to 81 and the organic EL devices Comparative Examples 1 to 14 prepared in Comparative Examples 1 to 14 were measured at room temperature in air when a direct current voltage was applied. The current-brightness-voltage properties of the devices were measured using a Keithley source meter (Keithley 2400 SourceMeter, Keithley 2000 CurrentMeter) with a calibrated silicon photodiode, the electroluminescence spectrum was measured using a Photo Research PR655 spectrometer, and the external quantum efficiency of the devices was calculated by the method described in Adv. Mater., 2003, 15, 1043-1048. The results are shown in Tables 4 and 5.

[0151] Table 4

[0152]

[0153] As can be seen from Table 4, the single-layer organic EL devices prepared from the compounds of the application are significantly higher in efficiency and lifetime than the single-layer organic EL devices Comparative Examples prepared from BH1 to BH7, and exhibit lower voltages, indicating that devices using the compounds of the application as the blue host material generally have more excellent performance.

[0154] Meanwhile, a comparison of seven organic EL devices revealed that, in order of longest to shortest lifetime, the order was: BH2 (aryl disubstituted) > BH5 (2,6,7-triaryl substituted) > BH4 (1,3,7-triaryl substituted) > BH7 (1,2,8-triaryl substituted) = BH3 (1,7,8-triaryl substituted) > BH6 (1-aryl-3,4-dialkoxy substituted) > BH1 (aryl monosubstituted). However, in order of lowest efficiency, the order was: BH1 (aryl monosubstituted) > BH6 (1-aryl-3,4-dialkoxy substituted) > BH5 (2,6,7-triaryl substituted) = BH7 (1,2,8-... The order of efficiency and lifetime of existing devices is: (triaryl-substituted) > BH4 (1,3,7-triaryl-substituted) > BH3 (1,7,8-triaryl-substituted) > BH2 (aryl disubstituted). This demonstrates that there is no clear correlation between the efficiency and lifetime of existing devices and the number, type, and substitution sites of substituents in the dibenzofuran compounds used as the main blue light source. In some cases, high efficiency is accompanied by short lifetime (and vice versa), making it impossible to achieve both performance goals simultaneously. However, the compounds of this invention creatively employ 1,3,4-triaryl substitution, which not only improves both device efficiency and lifetime but also reduces the device's operating voltage. These results were entirely unexpected by the inventors.

[0155] Comparing compound I-1 with I-2, I-5 and I-66, it was found that the devices corresponding to the dibenzofuran compounds of the present invention containing deuterium atoms are more efficient and have a longer lifespan than the devices corresponding to the compounds without deuterium atoms. It is speculated that this may be because the CD bond is more stable than the CH bond.

[0156] In addition, from Figure 4 The results shown indicate that when the dibenzofuran compounds of the present invention are used as the main material of the light-emitting layer in the device, the light emission pattern of the device is not affected, indicating that energy can be completely transferred to the light-emitting material in the device.

[0157] Table 5

[0158]

[0159] As shown in Table 5, compared with the comparative examples of stacked organic EL devices prepared by BH1 to BH7, the performance of stacked organic EL devices prepared by the compounds of the present invention (especially voltage) is significantly improved, indicating that devices using the compounds of the present invention as the blue light host material generally have better performance.

[0160] As can be seen from the above, the 1,3,4-triaryl-substituted dibenzofuran compounds of the present invention can effectively reduce the operating voltage and simultaneously improve the external quantum efficiency and extend the device lifetime compared with the blue light host materials commonly used in the prior art.

[0161] Industrial applicability

[0162] The 1,3,4-triaryl-substituted dibenzofuran compounds of this invention exhibit excellent luminous efficiency and lifetime characteristics, as well as low driving voltage. Therefore, organic electroluminescent devices with excellent lifetimes, especially blue organic electroluminescent devices, can be prepared from these compounds.

Claims

1. A compound as shown in Formula I, in, Each R 1 Each can independently represent a hydrogen atom or a deuterium atom; Ar1, Ar2, and Ar3 each independently represent any one of the following groups: in, Dashed lines represent bonding bonds; Each R 2 Each can be used independently to represent a hydrogen atom or a deuterium atom.

2. The compound according to claim 1, characterized in that, Each R 2 Both represent deuterium atoms.

3. The compound according to claim 1, characterized in that, The compound is represented by the following general formula I-1. in, Each R 1 Each can independently represent a hydrogen atom or a deuterium atom; Each R 2 Each can be independently represented as a hydrogen atom or a deuterium atom; Ar1 ​​is as defined in general formula I.

4. The compound according to claim 3, characterized in that, Each R 1 Both represent deuterium atoms; Each R 2 Both represent deuterium atoms.

5. The compound according to claim 3, characterized in that, The compound is represented by the following general formula I'-1. in, Each R 1 Each can independently represent a hydrogen atom or a deuterium atom; Each R 2 Each can independently represent a hydrogen atom or a deuterium atom; Ar1 is defined as in general formula I.

6. The compound according to claim 1, characterized in that, The compound is represented by the following general formula I-2. in, Each R 1 Each can independently represent a hydrogen atom or a deuterium atom; Each R 2 Each can independently represent a hydrogen atom or a deuterium atom; Ar1 is defined as in general formula I.

7. The compound according to claim 6, characterized in that, Each R 1 Both represent deuterium atoms; Each R 2 Both represent deuterium atoms.

8. The compound according to claim 6, characterized in that, The compound is represented by the following general formula I'-2. in, Each R 1 Each can independently represent a hydrogen atom or a deuterium atom; Each R 2 Each can independently represent a hydrogen atom or a deuterium atom; Ar1 is defined as in general formula I.

9. The compound according to claim 1, characterized in that, The compound is represented by the following general formula I-3. in, Each R 1 Each can independently represent a hydrogen atom or a deuterium atom; Each R 2 Each can independently represent a hydrogen atom or a deuterium atom; Ar1 is defined as in general formula I.

10. The compound according to claim 9, characterized in that, Each R 1 Both represent deuterium atoms; Each R 2 Both represent deuterium atoms.

11. The compound according to claim 9, characterized in that, The compound is represented by the following general formula I'-3. in, Each R 1 Each can independently represent a hydrogen atom or a deuterium atom; Each R 2 Each can independently represent a hydrogen atom or a deuterium atom; Ar1 is defined as in general formula I.

12. The compound according to claim 1, characterized in that, The compound is selected from any one of the following compounds:

13. A light-emitting device comprising a first electrode, a second electrode disposed opposite to the first electrode, and at least one organic layer sandwiched between the first electrode and the second electrode, said at least one organic layer comprising a compound according to any one of claims 1 to 12.

14. The light-emitting device according to claim 13, characterized in that, The light-emitting device is an organic electroluminescent device.

15. The light-emitting device according to claim 13, characterized in that, The light-emitting device is a blue organic electroluminescent device.

16. The light-emitting device according to claim 13, characterized in that, The at least one organic layer is a hole transport layer, an electron blocking layer, a light-emitting layer, a hole blocking layer, or an electron transport layer.

17. The light-emitting device according to claim 16, characterized in that, The at least one organic layer is a light-emitting layer.

18. The light-emitting device according to claim 17, characterized in that, The light-emitting layer comprises a host material and a guest material, wherein the host material comprises a compound according to any one of claims 1 to 12.

19. Use of the compound according to any one of claims 1 to 12 as a luminescent material in the preparation of luminescent devices.

20. The use according to claim 19, characterized in that, The luminescent material is the main material.

21. The use according to claim 19, characterized in that, The light-emitting device is an organic electroluminescent device.

22. The use according to claim 19, characterized in that, The light-emitting device is a blue organic electroluminescent device.

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