Organic electroluminescent compounds and their applications and organic electroluminescent devices

Abstract

The present invention relates to an organic electroluminescent compound, its application, and an organic electroluminescent device. The organic electroluminescent compound is represented by Formula I, wherein L1 and L2 are the same or different, each independently absent or selected from a substituted or unsubstituted arylene group and a substituted or unsubstituted heteroarylene group; and Ar1 and Ar2 are the same or different, each independently selected from a substituted or unsubstituted aryl group and a substituted or unsubstituted heteroaryl group. When used in an organic electroluminescent device, the organic electroluminescent compound of the present invention exhibits higher device luminous efficiency and a longer service life. #imgabs0#

Description

Technical Field

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

[0002] In 1987, Tang et al. from Kodak Company used a vacuum evaporation method to prepare a double-layer organic light-emitting diode (OLED) using aromatic diamine as a hole transport material and 8-hydroxyquinoline aluminum as a light-emitting and electron transport material. At a driving voltage below 10V, the device luminous brightness reached 1000cd / m 2 The luminous efficiency is 1.5lm / W, which makes organic electroluminescent devices practical.

[0003] As OLED technology continues to advance in the fields of lighting and display, device structures and materials for various functional layers require further optimization and development. High red, green, and blue luminescence efficiency, long lifetime, and high color purity are crucial for display applications, and numerous reports have been published on high-performance red and green OLEDs. Compared to red and green OLEDs, blue OLEDs exhibit relatively poor performance, necessitating improvements. Compared to blue phosphorescent OLEDs, blue fluorescent OLEDs often offer longer lifetimes and higher color purity. However, the internal quantum efficiency of conventional fluorescent OLEDs is limited to 25% because singlet and triplet excitons are generated in a ratio of approximately 1:3 upon electrical excitation. Therefore, the key to improving the efficiency of fluorescent OLEDs lies in utilizing triplet excitons. The triplet-triplet annihilation mechanism (TTA) upconverts the triplet excited state (T1) to the singlet excited state (S1), enabling internal quantum efficiencies of 40% to 62.5%. There have been some reports on efficient blue fluorescence using TTA, in which anthracene derivatives are used as the main material, but nowadays organic electroluminescent devices have low luminous efficiency and short service life. Therefore, improving the efficiency and life of blue light devices is an urgent breakthrough point. Summary of the Invention

[0004] In order to overcome the problems of high driving voltage, low luminous efficiency and short service life of organic electroluminescent devices provided by the prior art, the purpose of improving the efficiency of blue light devices is achieved by improving the utilization rate of invalid triplet excitons in the electrogenerated excitons in OLED blue light devices, while also increasing the service life of the devices.

[0005] In a first aspect, the present invention provides an organic electroluminescent compound as shown in Formula I,

[0006]

[0007] In Formula I, L1 and L2 are the same or different, each independently absent or selected from a substituted or unsubstituted arylene group and a substituted or unsubstituted heteroarylene group; Ar1 ​​and Ar2 are the same or different, each independently selected from a substituted or unsubstituted aryl group and a substituted or unsubstituted heteroaryl group.

[0008] According to the organic electroluminescent compound of the present invention, preferably, in formula I, L1 and L2 are the same or different, and are independently absent or selected from substituted or unsubstituted C6-C 20 Arylene and substituted or unsubstituted C3-C 20 of heteroarylene.

[0009] According to the organic electroluminescent compound of the present invention, preferably, in Formula I, Ar1 and Ar2 are each independently selected from substituted or unsubstituted C6-C 30 aryl and substituted or unsubstituted C3-C 30 of heteroaryl.

[0010] According to the organic electroluminescent compound of the present invention, preferably, in formula I, the heteroatom in the heteroaryl group is selected from one or more of nitrogen, oxygen, sulfur, phosphorus and silicon; the heteroatom in the heteroarylene group is selected from one or more of nitrogen, oxygen, sulfur, phosphorus and silicon.

[0011] According to the organic electroluminescent compound of the present invention, preferably, in Formula I, the substituents in the substituted arylene group, substituted heteroarylene group, substituted aryl group and substituted heteroaryl group are each independently selected from C1-C 10 Alkyl, C1-C 10 One or more of alkoxy, cyano and halogen.

[0012] According to the organic electroluminescent compound of the present invention, preferably, in formula I, L1 is absent or is a phenylene group, a naphthylene group, an anthrylene group or a phenanthrylene group.

[0013] According to the organic electroluminescent compound of the present invention, preferably, in formula I, L2 is absent or is a phenylene group, a naphthylene group, an anthrylene group or a phenanthrylene group.

[0014] According to the organic electroluminescent compound of the present invention, preferably, in formula I, Ar1 and Ar2 are each independently selected from substituted or unsubstituted phenyl, substituted or unsubstituted biphenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted dibenzofuranyl, substituted or unsubstituted dibenzothiophenyl, substituted or unsubstituted fluorenyl, substituted or unsubstituted 9,9-dimethylfluorenyl, substituted or unsubstituted carbazolyl, substituted or unsubstituted 9-phenylcarbazolyl, substituted or unsubstituted pyrenyl, substituted or unsubstituted triphenylenyl, substituted or unsubstituted terphenyl, substituted or unsubstituted phenanthrenyl, substituted or unsubstituted phenanthroline, substituted or unsubstituted 9,9'-spirobifluorenyl, substituted or unsubstituted substituted or unsubstituted benzo[9,10]phenanthrenyl, substituted or unsubstituted 9,9-dimethylfluorenyl, substituted or unsubstituted 9,9-diphenylfluorenyl, substituted or unsubstituted pyridyl, substituted or unsubstituted pyrimidinyl, substituted or unsubstituted triazinyl, substituted or unsubstituted benzofuranyl, substituted or unsubstituted isobenzofuranyl, substituted or unsubstituted quinolyl, substituted or unsubstituted isoquinolyl, substituted or unsubstituted quinazolinyl, substituted or unsubstituted benzothiophenyl, substituted or unsubstituted substituted or unsubstituted isobenzothiophenyl, substituted or unsubstituted indolizinyl, substituted or unsubstituted bicarbazolyl, substituted or unsubstituted azabenzo[9,10]phenanthryl, substituted or unsubstituted diazabenzo[9,10]phenanthryl, substituted or unsubstituted xanthenyl, substituted or unsubstituted azacarbazolyl, substituted or unsubstituted azadibenzofuranyl, substituted or unsubstituted azadibenzothiophenyl, substituted or unsubstituted diphenylphosphinoyl, substituted or unsubstituted triphenylsilyl and substituted or unsubstituted fluoranthenyl.

[0015] Specific examples of the organic electroluminescent compounds according to the present invention include, but are not limited to, the following compounds:

[0016]

[0017]

[0018]

[0019]

[0020]

[0021]

[0022]

[0023] In a second aspect, the present invention provides use of an organic electroluminescent compound represented by formula I in an organic electroluminescent device. According to an embodiment of the present invention, in the organic electroluminescent device, the organic electroluminescent compound is used as a light-emitting layer material, preferably as a host material of the light-emitting layer, and more preferably as a blue light host material.

[0024] In a third aspect, the present invention provides an organic electroluminescent device, comprising a light-emitting layer, wherein the light-emitting layer comprises the organic electroluminescent compound represented by formula I described above.

[0025] According to some embodiments of the present invention, the light-emitting layer further comprises a guest material, which is preferably a compound that produces emission via at least one of phosphorescence, fluorescence, TADF (thermally activated delayed fluorescence), MLCT (metal to ligand charge transfer), HLCT (with hybrid CT state) and triplet-triplet annihilation methods.

[0026] According to some embodiments of the present invention, the organic electroluminescent device of the present invention further comprises an anode, a hole injection layer, a hole transport layer, an optional electron blocking layer, an optional hole blocking layer, an electron transport layer, an electron injection layer and a cathode.

[0027] According to some embodiments of the present invention, the anode material forming the anode is generally preferably a material with a large work function. For example, the anode material used in the present invention is selected from one or more of the following materials: metals, such as vanadium, chromium, copper and gold, or other alloys: metal oxides, such as zinc oxide, indium oxide, indium tin oxide, indium zinc oxide and tin dioxide, combinations of metals and oxides, such as zinc oxide: aluminum, but not limited thereto.

[0028] According to some embodiments of the present invention, the material forming the hole injection layer has the ability to transport holes. Therefore, the material of the hole injection layer has an effect of injecting holes into the anode, has an excellent hole injection effect on the light-emitting layer or light-emitting material, prevents excitons generated in the light-emitting layer from migrating to the electron injection layer or electron injection material, and further has excellent thin film forming ability. The HOMO of the hole injection material is preferably between the work function of the anode material and the HOMO of the surrounding organic material layer.

[0029] According to some embodiments of the present invention, the hole injection material and the hole transport material include at least one of aromatic amine derivatives (such as NPB, SqMA1), hexaazatriphenylene derivatives (such as HACTN), indolecarbazole derivatives, conductive polymers (such as PEDOT / PSS), phthalocyanine or porphyrin derivatives, dibenzoindenofluorene amine, and spirodifluorene amine, but are not limited thereto.

[0030] According to some embodiments of the present invention, the hole injection layer and the hole transport layer may be formed using, for example, aromatic amine derivatives of the following general formula:

[0031]

[0032] The groups R1 to R9 in the above general formula are each independently selected from a single bond, hydrogen, deuterium, alkyl, benzene, biphenyl, terphenyl, naphthalene, anthracene, phenanthrene, triphenylene, pyrene, fluorene, dimethylfluorene, spirobifluorene, carbazole, thiophene, benzothiophene, dibenzothiophene, furan, benzofuran, dibenzofuran, indole, indolecarbazole, indenocarbazole, pyridine, pyrimidine, imidazole, thiazole, quinoline, isoquinoline, quinoxaline, quinazoline, porphyrin, carboline, pyrazine, pyridazine or triazine.

[0033] According to some embodiments of the present invention, the material for forming the electron blocking layer is not particularly limited. Generally, compounds that meet the first and / or second conditions below can be considered:

[0034] First: It has a shallower LUMO energy level (smaller absolute value), the purpose of which is to reduce the number of electrons leaving the light-emitting layer, thereby increasing the probability of electron and hole recombination in the light-emitting layer.

[0035] Second: It has a larger triplet energy, the purpose of which is to reduce the number of excitons leaving the light-emitting layer, thereby improving the efficiency of exciton conversion to luminescence.

[0036] According to some embodiments of the present invention, the materials forming the electron blocking layer include but are not limited to aromatic amine derivatives (such as NPB) and spirobifluorenamine (such as SpMA2), wherein some electron blocking materials have similar structures to hole injection materials and hole transport materials.

[0037] According to some embodiments of the present invention, the material of the hole blocking layer may also preferably be a compound having the following first and / or second conditions:

[0038] First: It has a deeper HOMO energy level (larger absolute value), the purpose of which is to reduce the number of holes leaving the light-emitting layer, thereby increasing the probability of electrons and holes being recombined in the light-emitting layer.

[0039] Second: It has a larger triplet energy, the purpose of which is to reduce the number of excitons leaving the light-emitting layer, thereby improving the efficiency of exciton conversion to luminescence.

[0040] According to some embodiments of the present invention, the material forming the hole blocking layer may include, for example, phenanthroline derivatives (eg, Bphen, BCP), triphenylene derivatives, and benzimidazole derivatives, but is not limited thereto.

[0041] According to some embodiments of the present invention, the electron injection layer is a layer that injects electrons from the electrode, and the electron injection material is preferably a compound having the following properties: the ability to transport electrons, the effect of injecting electrons from the cathode, the excellent effect of injecting electrons into the light-emitting layer or light-emitting material, the prevention of excitons generated in the light-emitting layer from migrating to the hole injection layer, and the excellent thin film forming ability. Examples of materials for the electron injection layer include, but are not limited to, LiF, CsF, Cs2CO3, and LiQ.

[0042] According to some embodiments of the present invention, the cathode material is preferably formed of a material with a small work function, which can smoothly inject electrons into the organic material layer. The cathode material that can be used in the present disclosure can be selected from one or more of the following materials, one or more of Al, Mg and Ag.

[0043] The present invention has at least the following specific advantages:

[0044] First, the parent nucleus of the present invention is anthracene connected to para-deuterated benzene connected to anthracene. Anthracene has a TTA effect. The present invention increases the utilization rate of triplet excitons through the synergistic effect of two anthracenes, thereby improving the luminous efficiency of the organic electroluminescent device.

[0045] Second, the deuterium atom in the para-deuterated benzene in the parent core structure has a larger atomic radius than that of the hydrogen atom, thus having stronger stability; at the same time, the deuterium atom interacts with anthracene, producing a larger angle, which effectively prevents the overlap of anthracene units between molecules, increases the glass transition temperature of the compound, and reduces the crystallinity of the compound, which can effectively improve the luminous efficiency and service life in electroluminescent devices.

[0046] Third, the mother core structure of the present invention has a large band gap and is suitable as a blue light host. The substituent groups on both sides can fine-tune the HOMO and LUMO of the compound, which can reduce the injection barrier of electrons and holes, thereby reducing the driving voltage of the device; at the same time, the compound of the present invention has a good carrier mobility rate, which can balance the mobility of electrons and holes in the device. When used in organic electroluminescent devices, it can obtain a wider carrier recombination area, thereby improving the luminous efficiency. DETAILED DESCRIPTION

[0047] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0048] The present invention has no particular limitation on the specific method for preparing the aforementioned compounds. Those skilled in the art can obtain the aforementioned compounds of the present invention based on the specific structural formula provided by the present invention in combination with conventional process routes in the field of organic synthesis. In addition, several examples are exemplarily listed later in the present invention to illustrate the preparation methods of the compounds of the present invention. Those skilled in the art can also obtain the specific preparation methods of all other compounds by replacing the types of raw materials according to the preparation methods of the compounds in the present invention. The present invention no longer describes the preparation methods of all compounds in detail, and those skilled in the art should not be understood as limiting the present invention.

[0049] The present invention will be described in detail below through examples. In the following examples, unless otherwise specified, all raw materials used are common commercial products. Unless otherwise specified, the room temperature described below refers to 25±1°C.

[0050] Preparation Example 1:

[0051]

[0052] Synthesis of Intermediate A-1: ​​To a 500ml three-necked flask, add a mixed solution of 1,4-dibromodeuterated benzene (0.012mol), 9-anthracene borates (0.024mol), toluene (30ml), ethanol (20ml), and water (10ml) in sequence and begin stirring. Potassium carbonate (0.06mol) and tetrakis(triphenylphosphine)palladium (0.24mmol) are then added in sequence. The temperature is raised to reflux for 4 hours. HPLC analysis confirms the substantial reaction of the starting materials. Deionized water (100ml) is added to the reaction solution and stirred for 10 minutes. The organic phase is washed three times with toluene, combined, and dried over anhydrous magnesium sulfate. The desiccant is filtered, the organic solvent is evaporated, and the residue is separated by silica gel chromatography to obtain A-1 as a white solid (yield: 72%).

[0053] Synthesis of intermediate A: In a 500ml three-necked flask, A-1 (0.05 mol) was dissolved in N,N-dimethylformamide (220 ml), and N,N-dimethylformamide solution (178 ml) containing NBS (0.1 mol) was added dropwise. After the addition was completed, the temperature was raised to 100 ° C and stirred for 15 h. HPLC detection showed that the reaction of the raw material was basically completed. The reaction solution was cooled to room temperature and water (300 ml) was added dropwise. After stirring for 30 min, the crude product was filtered and dried to obtain intermediate A (yield 75%).

[0054] Mass spectrum: C34H16D4Br2, theoretical value: 590.02, found value: 590.1. 1H-NMR (400 MHz, CDCl3) (ppm) δ = 7.49 ~ 7.54 (8H, m), 8.16 ~ 8.20 (4H, m), 8.29 ~ 8.33 (4H, m).

[0055] Preparation Example 2:

[0056]

[0057] Synthesis of intermediate B: In a 500ml three-necked flask, A-1 (0.03 mol) was dissolved in N,N-dimethylformamide (130 ml), and N,N-dimethylformamide solution (53 ml) containing NBS (0.03 mol) was added dropwise. After the addition was completed, the temperature was raised to 100°C and stirred for 8 hours. HPLC detection showed that the reaction of the raw materials was basically completed. The reaction solution was cooled to room temperature and water (200 ml) was added dropwise. After stirring for 20 minutes, the crude product was filtered to obtain the crude product, which was recrystallized three times from dichloromethane to obtain intermediate B (yield: 56%).

[0058] Mass spectrum: C34H17D4Br, theoretical value: 512.11, found value 512.1. 1H-NMR (400MHz, CDCl3) (ppm) δ = 7.42~7.55 (8H, m), 8.05~8.10 (2H, m), 8.14~8.23 (4H, m), 8.27~8.35 (2H, m), 8.44~8.46 (1H, m).

[0059] Preparation Example 3:

[0060]

[0061] Synthesis of compound 5: The synthesis method is the same as that of intermediate A-1, and an off-white solid is obtained (yield: 70%).

[0062] Mass spectrum: C54H30D4, theoretical value: 686.29, found value: 686.3. 1H-NMR (400MHz, CDCl3) (ppm) δ = 7.32~7.36 (2H, m), 7.38~7.46 (10H, m), 7.75~7.80 (4H, m), 7.87~7.91 (2H, m), 8.19~8.24 (8H, m), 8.47~8.52 (2H, m), 8.94~8.97 (2H, m).

[0063] Preparation Example 4:

[0064]

[0065] Synthesis of compound 6: The synthesis method is the same as that of intermediate A-1, and a white solid is obtained (yield: 76%).

[0066] Mass spectrum: C54H30D4, theoretical value: 686.29, found value: 686.3. 1H-NMR (400MHz, CDCl3) (ppm) δ = 7.36~7.39 (2H, m), 7.41~7.45 (8H, m), 7.54~7.65 (6H, m), 7.97~8.01 (2H, m), 8.05~8.11 (4H, m), 8.19~8.23 (8H, m).

[0067] Preparation Example 5:

[0068]

[0069] Synthesis of compound 17: The synthesis method was the same as that of intermediate A-1, and an off-white solid was obtained (yield: 73%).

[0070] Mass spectrum: C58H30D4O2, theoretical value: 766.28, found value: 766.3. 1H-NMR (400MHz, CDCl3) (ppm) δ = 7.29~7.33 (2H, m), 7.37~7.45 (10H, m), 7.52~7.56 (2H, m), 7.61~7.65 (2H, m), 7.68~7.71 (2H, m), 7.94~8.00 (2H, m), 8.18~8.24 (8H, m), 9.43~9.46 (2H, m).

[0071] Preparation Example 6:

[0072]

[0073] Synthesis of compound 20: The synthesis method was the same as that of intermediate A-1 to obtain an off-white solid (yield: 78%).

[0074] Mass spectrum: C58H30D4S2, theoretical value: 798.24, found value: 798.3. 1H-NMR (400 MHz, CDCl3) (ppm) δ = 7.27~7.35 (2H, m), 7.39~7.47 (10H, m), 7.52~7.60 (2H, m), 7.84~7.89 (2H, m), 7.94~7.99 (2H, m), 8.15~8.25 (10H, m), 8.42~8.48 (2H, m).

[0075] Preparation Example 7:

[0076]

[0077] Synthesis of compound 34: The synthesis method was the same as that of intermediate A-1 to obtain an off-white solid (yield: 69%).

[0078] Mass spectrum: C70H38D4, theoretical value: 886.35, found value: 886.4. 1H-NMR (400MHz, CDCl3) (ppm) δ = 7.39~7.47 (8H, m), 7.49~7.55 (4H, m), 7.60~7.74 (8H, m), 8.17~8.40 (14H, m), 9.16~9.21 (1H, m), 9.46~9.50 (1H, m), 9.57~9.63 (2H, m).

[0079] Preparation Example 8:

[0080]

[0081] Synthesis of compound 38: The synthesis method was the same as that of intermediate A-1 to obtain an off-white solid (yield: 72%).

[0082] Mass spectrum: C66H34D4O2, theoretical value: 866.31, found value: 866.4. 1H-NMR (400MHz, CDCl3) (ppm) δ = 7.26~7.31 (2H, m), 7.39~7.46 (8H, m), 7.48~7.66 (8H, m), 7.76~7.81 (2H, m), 7.96~8.02 (2H, m), 8.17~8.25 (8H, m), 8.51~8.57 (2H, m), 9.19~9.21 (2H, m).

[0083] Preparation Example 9:

[0084]

[0085] Synthesis of compound 57: The synthesis method was the same as that of intermediate A-1 to obtain an off-white solid (yield: 70%).

[0086] Mass spectrum: C66H34D4S2, theoretical value: 898.27, found value: 898.3. 1H-NMR (400MHz, CDCl3) (ppm) δ = 7.39~7.50 (11H, m), 7.73~7.77 (2H, m), 7.82~7.86 (2H, m), 7.95~7.99 (2H, m), 8.14~8.33 (15H, m), 8.76~8.79 (1H, m), 9.11~9.13 (1H, m).

[0087] Preparation Example 10:

[0088]

[0089] Synthesis of Intermediate 72-1: To a 500ml three-necked flask, a mixed solution of Intermediate B (0.03 mol), 1-naphthaleneboronic acid (0.03 mol), toluene (75 ml), ethanol (50 ml), and water (25 ml) was added in sequence and stirred. Potassium carbonate (0.075 mol) and tetrakis(triphenylphosphine)palladium (0.3 mmol) were then added in sequence. The temperature was raised to reflux for 5 hours. HPLC analysis confirmed the substantial reaction of the starting materials. Deionized water (200 ml) was added to the reaction solution and stirred for 10 minutes. The organic phase was washed three times with toluene, combined, and dried over anhydrous magnesium sulfate. The desiccant was filtered, the organic solvent was evaporated, and the residue was separated by silica gel chromatography to obtain 72-1 as a white solid (yield: 78%).

[0090] Synthesis of Intermediate 72-2: The synthesis method is the same as that of Intermediate B, and a white solid is obtained (yield: 57%).

[0091] Synthesis of compound 72: The synthesis method was the same as that of intermediate 72-1 to obtain a white solid (yield: 72%).

[0092] Mass spectrum: C60H34D4, theoretical value: 762.32, found value: 762.3. 1H-NMR (400MHz, CDCl3) (ppm) δ = 7.23~7.26 (4H, s), 7.30~7.47 (11H, m), 7.54~7.67 (3H, m), 7.73~7.80 (2H, m), 7.87~7.91 (1H, m), 7.95~8.01 (1H, m), 8.04~8.12 (2H, m), 8.17~8.25 (8H, m), 8.46~8.54 (1H, m), 8.93~8.98 (1H, m).

[0093] Preparation Example 11:

[0094]

[0095] Synthesis of compound 75: The synthesis method was the same as that of intermediate 72-1 to obtain a white solid (yield: 78%).

[0096] Mass spectrum: C54H30D4, theoretical value: 686.29, found value: 686.3. 1H-NMR (400MHz, CDCl3) (ppm) δ = 7.32~7.45 (11H, m), 7.54~7.65 (3H, m), 7.75~7.79 (2H, m), 7.87~7.91 (1H, m), 7.97~8.01 (1H, m), 8.05~8.11 (2H, m), 8.19~8.23 (8H, m), 8.48~8.52 (1H, m), 8.93~8.96 (1H, m).

[0097] Device Example 1

[0098] Glass plates coated with an ITO transparent conductive layer were ultrasonically treated in a commercial cleaning agent, rinsed in deionized water, ultrasonically degreased in a 1:1 acetone:ethanol mixed solvent, baked in a clean environment to completely remove the water, cleaned with ultraviolet light and ozone, and bombarded with a low-energy cation beam.

[0099] Place the glass substrate with the anode in a vacuum chamber and evacuate to 1×10 -5 Pa, vacuum evaporation HAT-CN as a hole injection layer on the above-mentioned anode layer film at a rate of 0.1 nm / s and a total evaporation film thickness of 1 nm; then evaporation of the hole transport layer NPB at a rate of 0.1 nm / s and a thickness of 60 nm;

[0100] The electron blocking layer TCTA of the device is vacuum evaporated on the hole transport layer at a rate of 0.1 nm / s and a total film thickness of 10 nm.

[0101] The light-emitting layer of the device is vacuum-deposited on the electron blocking layer. The light-emitting layer includes a host material and a guest material. The multi-source co-evaporation method is used to adjust the evaporation rate of the host material compound 5 to 0.1nm / s, and the evaporation rate of the guest material BD is set at 5% of the ratio. The total film thickness of the evaporation is 30nm.

[0102] The hole blocking layer TPBi of the device was vacuum-deposited on top of the light-emitting layer at a rate of 0.1 nm / s and a thickness of 5 nm. The electron transport layer was then evaporated using a multi-source co-evaporation method, with the evaporation rate of both ET-1 and ET-2 adjusted to 0.1 nm / s, and the total film thickness was 30 nm.

[0103] LiF with a thickness of 0.5 nm was vacuum evaporated on the electron transport layer (ETL) as the electron injection layer, and an Al layer with a thickness of 150 nm was used as the cathode of the device.

[0104] The molecular structures involved are as follows:

[0105]

[0106] Device Examples 2-9

[0107] Organic light-emitting devices of Device Examples 2 to 9 were prepared using a method similar to that of Device Example 1, except that Compound 5 in Device Example 1 was replaced with the compounds shown in Table 1.

[0108] Device Comparative Examples 1-4

[0109] An organic electroluminescent device of Comparative Example 1 was prepared by a method similar to that of Device Example 1, except that Compound 5 in Device Example 1 was replaced by the following compounds ref-1, ref-2, ref-3 and ref-4, respectively.

[0110]

[0111] Test Example 1

[0112] At a brightness of 1000cd / m 2 The driving voltage and current efficiency of the organic electroluminescent devices prepared in device examples 1 to 9 and device comparative examples 1 to 4 were measured. The results are shown in Table 1.

[0113] Table 1

[0114] Example No. Blu-ray main material <![CDATA[Required luminance (cd / m 2 )]]> Driving voltage (V) Current efficiency (cd / A) Example 1 Compound 5 1000 4.33 6.86 Example 2 Compound 6 1000 4.26 6.89 Example 3 Compound 17 1000 4.48 6.91 Example 4 Compound 20 1000 4.35 6.83 Example 5 Compound 34 1000 4.44 6.72 Example 6 Compound 38 1000 4.53 6.78 Example 7 Compound 57 1000 4.60 6.79 Example 8 Compound 72 1000 4.56 6.88 Example 9 Compound 75 1000 4.42 6.98 Comparative Example 1 Ref-1 1000 4.43 5.94 Comparative Example 2 Ref-2 1000 4.65 5.88 Comparative Example 3 Ref-3 1000 4.38 5.98 Comparative Example 4 Ref-4 1000 4.43 6.09

[0115] The above results show that, compared with the comparative example, the organic electroluminescent compound of the present invention has higher device luminescence efficiency when applied to an organic electroluminescent device.

[0116] Test Example 2

[0117] At a brightness of 1000cd / m 2 The lifespans of the organic electroluminescent devices prepared in device examples 10 to 12 and device comparative examples 5 to 7 were measured. The results are shown in Table 2.

[0118] Example No. Blu-ray main material <![CDATA[Required brightness (cd / m 2 )]]> Lifespan T90 is based on Comparative Example 5 Example 10 Compound 5 1000 122 Example 11 Compound 6 1000 119 Example 12 Compound 75 1000 126 Comparative Example 5 Ref-1 1000 100 Comparative Example 6 Ref-3 1000 105 Comparative Example 7 Ref-4 1000 108

[0119] The above results show that compared with the comparative example, the organic electroluminescent compound of the present invention has a longer service life when applied to an organic electroluminescent device.

[0120] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as the contents disclosed by the present invention and fall within the scope of protection of the present invention.

Claims

1. An organic electroluminescent compound as shown in formula I, In formula I, L1 does not exist, or is phenylene, naphthylene, anthrylene or phenanthrylene; L2 does not exist, or is phenylene, naphthylene, anthrylene or phenanthrylene; Ar1 and Ar2 are each independently selected from substituted or unsubstituted phenyl, substituted or unsubstituted biphenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted dibenzofuranyl, substituted or unsubstituted dibenzothiophenyl, substituted or unsubstituted triphenylenyl, substituted or unsubstituted phenanthrenyl; The substituted substituents are each independently selected from C1-C 10 Alkyl, C1-C 10 One or more of alkoxy, cyano and halogen.

2. An organic electroluminescent compound, characterized in that The organic electroluminescent compound is selected from the following compounds:

3. Use of the organic electroluminescent compound according to any one of claims 1 to 2 in an organic electroluminescent device.

4. The use according to claim 3, characterized in that The organic electroluminescent compound is used as the light-emitting layer material.

5. The use according to claim 4, characterized in that The organic electroluminescent compound is used as the main material of the light-emitting layer.

6. The use according to claim 5, characterized in that The organic electroluminescent compound serves as a blue light host material.

7. An organic electroluminescent device comprising a light-emitting layer, wherein the light-emitting layer comprises the organic electroluminescent compound according to any one of claims 1 to 2.

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