A compound with electron transport function, an organic electroluminescent device containing the same and its application

Abstract

The present invention discloses a compound with an electron transport function, an organic electroluminescent device containing the same, and applications thereof. The compound with an electron transport function can be used as an electron transport layer or a hole blocking layer. The compound with an electron transport function has a structure shown in Formula I: the compound with an electron transport function is obtained by connecting an alkyl fluorenyl group and a triazine side chain thereto. The compound is used as an electron transport layer or hole blocking layer material and has the advantages of reducing driving voltage, improving luminous efficiency, and extending service life.

Description

Technical Field

[0001] The present invention belongs to the technical field of organic photoelectric materials, and in particular relates to a compound with electron transport function, an organic electroluminescent device containing the compound, and applications thereof. Background Art

[0002] With the rapid development of information technology, new goals and requirements have been set for the performance of information display systems. How to achieve high brightness, high resolution, wide viewing angles, and low energy consumption has become a hot research topic. Currently, OLEDs are gradually being applied to high-end display applications such as mobile phones, wearable devices, automotive displays, and computers. An increasing number of companies are also developing foldable and rollable OLED screens to meet people's demand for a larger screen experience and product portability.

[0003] Organic light-emitting devices (OLEDs) convert electrical energy into light by applying power to an organic electroluminescent material. They typically consist of an anode, a cathode, and an organic layer formed between or outside the two electrodes. The organic layer includes an electron-transporting material, which regulates the rate and amount of electron injection. Electron-transporting materials primarily transport electrons, typically requiring a low LUMO (lowest unoccupied molecular orbital) energy level and containing electron-withdrawing groups such as halogens, pyridines, triazines, triazoles, and hydroxyls to facilitate electron absorption. The LUMO energy level should be closely matched to the cathode's work function to maximize electron injection and transport. Furthermore, the HOMO (highest occupied molecular orbital) energy level of the electron-transporting material should be as large as possible to block the transfer of holes from the luminescent layer to the cathode, confining more holes to form excitons in the luminescent layer and generate light.

[0004] However, there are currently few materials with excellent performance that can be used as electron transport layers, especially the lifespan and luminous efficiency of organic electroluminescent materials have not been significantly improved. Therefore, it is particularly important to develop higher-performance organic materials for electron transport layers and promote the industrialization process. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the present invention provides a compound with electron transport function, an organic electroluminescent device containing the same and its application, Alkylfluorenyl and triazine side chains are connected thereto, and the resulting compound can be used as a material for an electron transport layer or a hole blocking layer, and has the advantages of reducing driving voltage, improving luminous efficiency and extending service life.

[0006] In order to solve the above problems, the present invention provides the following technical solutions:

[0007] In a first aspect, the present invention provides a compound having an electron transport function, which serves as an electron transport layer or a hole blocking layer. The compound having an electron transport function has a structure shown in Formula I:

[0008] ,

[0009] Among them, at least one of X1-X3 is N, and the rest are C;

[0010] Ar1, Ar2 are independently selected from the following groups which may be substituted or unsubstituted by deuterium, and are substituted at the substitutable positions:

[0011]

[0012] L1 is independently selected from a chemical bond, a deuterium-substituted or unsubstituted phenyl, a naphthyl, a biphenyl group, and a terphenyl group;

[0013] X is independently selected from O, S, CR3R4, NR5, wherein R3 R5 are independently selected from C1 substituted or unsubstituted by deuterium C6 alkyl; C6 substituted or unsubstituted by deuterium C 12 aryl;

[0014] R is selected from C1-C6 alkyl groups which may be substituted or unsubstituted by deuterium;

[0015] Furthermore, Formula I has the structure shown in Formula a-Formula d:

[0016]

[0017] Among them, there are at least two Ns in X1-X3;

[0018] R is selected from the following groups which may be substituted or unsubstituted by deuterium: methyl, ethyl, propyl, butyl, pentyl, hexyl;

[0019] R3, R4 are selected from methyl substituted or unsubstituted by deuterium;

[0020] R5 is selected from the following groups which may be substituted by deuterium: phenyl, naphthyl, biphenyl;

[0021] Furthermore, R is selected from one or more of -CH3, -CD3, -CHD2, -CH2D, -CH2-CH3, -CD2CD3;

[0022] R3, R4 are independently selected from -CH3, -CD3, -CHD2, -CH2D;

[0023] R5 is selected from:

[0024] ;

[0025] L1 is independently selected from a chemical bond, and the following groups:

[0026] ;

[0027] Wherein, D is deuterium, n is an integer selected from 0-9, and * represents the connection position;

[0028] In the present invention, the substitution positions are defined as follows:

[0029] .

[0030] In one embodiment of the present invention, the compound having electron transport function is any one of the following structures, but is not limited thereto:

[0031]

[0032]

[0033]

[0034]

[0035]

[0036]

[0037]

[0038]

[0039]

[0040]

[0041]

[0042]

[0043]

[0044]

[0045]

[0046]

[0047] In a second aspect, the present invention further provides a method for synthesizing a compound having electron transport function, which specifically comprises:

[0048] Under nitrogen protection, reactant aI (1.0 eq) was dissolved in tetrahydrofuran (THF), magnesium (Mg) (1.0-2.0 eq) was added, and the mixture was stirred at 80-85°C for 2-4 hours. A solution of reactant bI (1.0 eq) dissolved in THF was added at 0°C, and the mixture was stirred at room temperature for 4-6 hours. The reaction was terminated with 2M hydrochloric acid, and the reaction product was extracted with dichloromethane (CH2Cl2) and water. The organic layer was dried over anhydrous magnesium sulfate (MgSO4) and concentrated. The residual material was purified by column chromatography to obtain intermediate cI.

[0049] Under nitrogen protection, intermediate cI (1.0 eq) was added with reactant dI (1.0-1.5 eq), tris(dibenzylideneacetone)dipalladium (Pd2(dba)3) (0.01-0.05 eq), potassium acetate (AcOK) (2.0-4.0 eq), and N,N-dimethylformamide (DMF). The mixture was stirred at 150-170°C for 18-24 hours. The mixture was then cooled to room temperature and washed with water. The remaining material was purified by column chromatography to obtain intermediate eI.

[0050] Under N2 protection, the intermediate eI (1.0 eq), the reactant fI (1.0-1.4 eq), palladium acetate (Pd(OAc)2) (0.02-0.04 eq) and 2-cyclohexyl-2,4,6-triisopropylbiphenyl (X-Phos) (0.05-0.1 eq), and cesium carbonate (Cs2CO3) (2.0-3.0 eq) were respectively added to a mixed solvent of toluene (Toluene), ethanol (EtOH), and water, the temperature was raised to 80-90°C, the reaction was carried out for 10-16 hours, and the reaction was cooled to room temperature. H2O was added, and after the solid was precipitated, it was filtered, and the remaining substance was purified by column chromatography to obtain Formula I.

[0051] Synthesis route:

[0052] .

[0053] In a third aspect, the present invention also provides an organic electroluminescent device comprising an anode, a cathode, and an organic layer arranged between the anode and the cathode; the organic layer comprises one or more of a hole injection layer, a hole transport layer, an electron blocking layer, a luminescence auxiliary layer, a luminescent layer, a hole blocking layer, an electron transport layer, an electron injection layer, and a capping layer; the hole blocking layer and / or the electron transport layer contains a compound having an electron transport function of the structure shown in the above formula I.

[0054] The structure of the organic electroluminescent device is not limited thereto and may include fewer or more organic layers.

[0055] In one embodiment of the present invention, when manufacturing an organic electroluminescent device, the organic layer is formed by vacuum evaporation or solution coating.

[0056] In one embodiment of the present invention, the solution coating method includes one or more of spin coating, dip coating, blade coating, inkjet printing, screen printing, spraying and roller coating, but is not limited thereto.

[0057] In one embodiment of the present invention, the organic electroluminescent device is classified as a top emission type, a bottom emission type or a bi-directional emission type according to the materials used.

[0058] As the anode material, a material having a large work function is generally preferred so that holes can be smoothly injected into the organic material layer.

[0059] In one embodiment of the present invention, specific examples of anode materials that can be used include: metals such as vanadium, chromium, copper, zinc and gold, or alloys thereof; metal oxides such as zinc oxide, indium oxide, indium tin oxide (ITO) and indium zinc oxide (IZO); combinations of metals and oxides such as ZnO:Al or SnO2:Sb; conductive polymers such as poly(3-methylthiophene), poly[3,4-(ethylene-1,2-dioxy)thiophene] (PEDOT), polypyrrole and polyaniline, but are not limited thereto.

[0060] The hole injection material is a material that advantageously receives holes from the anode at a low voltage, and the highest occupied molecular orbital (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.

[0061] In one embodiment of the present invention, the material of the hole injection layer includes metal porphyrin, oligothiophene, organic material based on aromatic amine, organic material based on hexanitrile hexaazatriphenylene, organic material based on quinacridone, organic material based on perylene, anthraquinone, and conductive polymers based on polyaniline and polythiophene, etc., but is not limited thereto, and may also include other compounds capable of p-doping.

[0062] The material of the hole transport layer is a material that can receive holes from the anode or the hole injection layer and transport the holes to the light emitting layer, and a material having high hole mobility is suitable.

[0063] In one embodiment of the present invention, the material of the hole transport layer includes an organic material based on arylamine, a conductive polymer, a block copolymer having both a conjugated portion and a non-conjugated portion, etc., but is not limited thereto.

[0064] The light-emitting layer can emit red, green, or blue light and can be formed of a phosphorescent material or a fluorescent material. The material of the light-emitting layer is a material that can emit light in the visible light region by receiving holes and electrons from the hole transport layer and the electron transport layer, respectively, and combining the holes with the electrons. It is preferably a material with favorable quantum efficiency for fluorescence or phosphorescence.

[0065] In one embodiment of the present invention, the material of the light-emitting layer includes: 8-hydroxyquinoline aluminum complex (Alq3); carbazole-based compounds; diphenylethylene compounds; BAlq; 10-hydroxybenzoquinoline-metal compounds; benzocarbazole-based, benzothiazole-based and benzimidazole-based compounds; poly(p-phenylene vinylene) (PPV)-based polymers; spiro compounds; polyfluorene; rubrene, etc., but are not limited thereto.

[0066] In one embodiment of the present invention, the light-emitting layer comprises a host material and a dopant material.

[0067] In one embodiment of the present invention, the host material of the light-emitting layer includes fused aromatic ring derivatives, heterocyclic compounds, and the like.

[0068] Specifically, the fused aromatic ring derivatives include anthracene derivatives, pyrene derivatives, naphthalene derivatives, pentacene derivatives, phenanthrene compounds, fluoranthene compounds, etc., and the heterocyclic compounds include carbazole derivatives, dibenzofuran derivatives, ladder-type furan compounds, pyrimidine derivatives, etc., however, the materials are not limited thereto.

[0069] In one embodiment of the present invention, the doping material of the light-emitting layer includes fluorescent doping and phosphorescent doping.

[0070] For example, it can be selected from aromatic amine derivatives, styrylamine compounds, boron complexes, fluoranthene compounds, metal complexes, and the like.

[0071] The hole blocking layer blocks the holes from the anode at the interface of the device's light-emitting layer, thereby increasing the probability of recombination between electrons and holes at the interface of the device's light-emitting layer and increasing the luminous efficiency of the device.

[0072] The compound represented by the structure of formula I in the present invention can be used as the material of the hole blocking layer.

[0073] The electron transport layer can facilitate electron transport. The electron transport material is a material that advantageously receives electrons from the cathode and transports the electrons to the light-emitting layer, and preferably uses a material with high electron mobility.

[0074] The compound of the structure represented by formula I in the present invention can be used as an electron transport layer material.

[0075] The electron injection layer can facilitate electron injection. The electron injection material is preferably a compound that has the ability to transport electrons, has an effect of injecting electrons from the cathode, has an excellent electron injection effect on the light-emitting layer or light-emitting material, prevents excitons generated in the light-emitting layer from migrating to the hole injection layer, and, in addition, has excellent thin film forming ability.

[0076] For example, materials for the electron injection layer include fluorenone, anthraquinone dimethane, diphenoquinone, thiopyran dioxide, azole, diazole, triazole, imidazole, perylenetetracarboxylic acid, fluorenyl methane, anthrone, and their derivatives, metal complexes, nitrogen-containing 5-membered ring derivatives, etc., but are not limited thereto.

[0077] As the cathode material, a material having a small work function is generally preferred so that electrons can be smoothly injected into the organic material layer.

[0078] In one embodiment of the present invention, the cathode material includes: metals such as magnesium, calcium, sodium, potassium, titanium, indium, yttrium, lithium, gadolinium, aluminum, silver, tin and lead, or alloys thereof; multilayer structure materials such as LiF / Al or LiO2 / Al; and the like, but are not limited thereto.

[0079] In a fourth aspect, the present invention also provides an organic electroluminescent device for use in a flat panel display, a computer monitor, a medical monitor, a television, a billboard, a lamp for interior or exterior lighting and / or signaling, a head-up display, a fully transparent or partially transparent display, a flexible display, a laser printer, a telephone, a mobile phone, a tablet, a photo album, a personal digital assistant (PDA), a wearable device, a laptop computer, a digital camera, a video camera, a viewfinder, a microdisplay, a three-dimensional display, a virtual reality or augmented reality display, a vehicle, a video wall comprising multiple displays tiled together, a theater or stadium screen, a light therapy device and a sign.

[0080] Beneficial effects of the present invention:

[0081] The present invention provides a compound having electron transport function. The compound is obtained by connecting an alkylfluorenyl group and a triazine side chain thereto. When the compound is used as a material for an electron transport layer or a hole blocking layer, it has the advantages of reducing driving voltage, improving luminous efficiency and extending service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0082] Figure 1 is the H NMR spectrum of compound 40. DETAILED DESCRIPTION

[0083] The technical solutions of the present invention will be described in further detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanations of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are encompassed within the scope of protection that the present invention is intended to protect.

[0084] Unless otherwise stated, the raw materials and reagents used in the following examples are commercially available products.

[0085] Example 1

[0086] Synthesis of compound 40

[0087]

[0088] CAS: reactant a-40:70402-38-9

[0089] CAS: reactant b-40:2087889-86-7

[0090] CAS: reactant f-40:2260561-71-3

[0091] Under nitrogen protection, reactant a-40 (1.0 eq) was dissolved in THF, Mg (1.5 eq) was added, and the mixture was stirred at 85°C for 2 hours. THF and reactant b-40 (1.0 eq) were added at 0°C, and the mixture was stirred at room temperature for 4 hours. The reaction was terminated with 2M hydrochloric acid, and the reaction product was extracted with CH2Cl2 and water. The organic layer was dried over anhydrous MgSO4 and concentrated. The remaining material was purified by column chromatography to obtain intermediate c-40 (yield: 76.2%, MS (ESI, m / Z): [M+H]+ = 380.48).

[0092] Under nitrogen protection, reactant d-40 (1.0 eq), Pd(dba) (0.03 eq), AcOK (3.0 eq), and DMF were added to intermediate c-40 (1.0 eq), and stirred at 150°C for 24 hours. The mixture was then cooled to room temperature and washed with water. The remaining material was purified by column chromatography to obtain intermediate e-40 (yield: 80.6%, MS (ESI, m / Z): [M+H]+ = 472.35).

[0093] Under N2 protection, intermediate e-40 (1.0 eq), reactant f-40 (1.2 eq), Pd(OAc)2 (0.02 eq), X-Phos (0.05 eq), and Cs2CO3 (2.1 eq) were respectively added to a mixed solvent of toluene, ethanol, and water. The temperature was raised to 80°C, the reaction was carried out for 10 h, and the reaction was cooled to room temperature. H2O was added, and after the solid was precipitated, it was filtered and the remaining substance was purified by column chromatography to obtain compound 40 (yield: 83.1%, test value MS (ESI, m / Z): [M+H]+ = 679.26).

[0094] The yield in each of the above steps is the fractional yield of the corresponding step.

[0095] Characterization: HPLC purity: >99.8%.

[0096] Elemental analysis:

[0097] Theoretical values: C, 84.93; H, 4.45; N, 8.25; O, 2.36

[0098] Found: C, 84.76; H, 4.51; N, 8.40; O, 2.39.

[0099] Figure 1 This is the hydrogen nuclear magnetic resonance spectrum of compound 40 prepared in Example 1.

[0100] The other compounds of the present application can be obtained by referring to the synthesis methods of the above-mentioned synthesis examples, so they are not listed here one by one. The mass spectrometer model is Waters XEVO TQD, low precision, ESI source test.

[0101] Application Example 1-Application Example 82

[0102] Formula I as electron transport material for preparing organic electroluminescent devices

[0103] Application Example 1

[0104] ITO anode: A 150nm thick ITO (indium tin oxide)-Ag-ITO (indium tin oxide) glass substrate was cleaned twice in distilled water, ultrasonically cleaned for 30 minutes, then repeatedly cleaned twice in distilled water, ultrasonically cleaned for 10 minutes, and then baked in a vacuum oven at 220°C for 2 hours. After baking, the substrate was cooled and ready for use. This substrate served as the anode and was deposited using an evaporation device. Other functional layers were then deposited on top.

[0105] b. HIL (Hole Injection Layer): Vacuum-deposit the HIL materials HT-1 and P-dopant at a rate of 1 Å / s. The chemical formulas are shown below. The HT-1 and P-dopant were deposited at a rate ratio of 95:5 to a thickness of 10 nm.

[0106] c. HTL (hole transport layer): 120 nm of HT-1 was vacuum-deposited on the hole injection layer at a deposition rate of 1.5 Å / s as a hole transport layer. The chemical formula is shown below.

[0107] d. Prime (luminescent auxiliary layer): 5 nm of prime-1 is vacuum-deposited on the hole transport layer at a deposition rate of 0.5 Å / s as a luminescent auxiliary layer. Its chemical formula is shown below.

[0108] e. EML (Emitting Layer): A host material (Host-1) and a dopant material (Dopant-1) with a thickness of 30 nm were vacuum-deposited on the light-emitting auxiliary layer at a deposition rate of 1 Å / s. The chemical formulas of Host-1 and Dopant-1 are shown below. The deposition rate ratio of Host-1 to Dopant-1 was 95:5.

[0109] f. HB (hole blocking layer): HB-1 with a thickness of 5.0 nm was vacuum-deposited on the light-emitting layer at a deposition rate of 0.5 Å / s as a hole blocking layer. The chemical formula of the layer is shown below.

[0110] g. ETL (electron transport layer): Compound 40 and Liq were vacuum evaporated on the hole blocking layer to a thickness of 30 nm at a deposition rate of 1 Å / s. The deposition rate ratio of the compound 40 and Liq was 50:50.

[0111] h. EIL (electron injection layer): A Yb film with a thickness of 1.0 nm is evaporated on the electron transport layer at an evaporation rate of 0.5 Å / s to form an electron injection layer.

[0112] i. Cathode: Magnesium and silver were evaporated on the electron injection layer at a deposition rate of 1 Å / s to a thickness of 13 nm. The deposition rate ratio of magnesium to silver was 1:9 to obtain a cathode.

[0113] j. Light extraction layer: CPL-1 was vacuum-deposited on the cathode at a deposition rate of 1 Å / s to a thickness of 70 nm as a light extraction layer. The chemical formula of CPL-1 is shown below.

[0114] k. Package the vapor-deposited substrate: First, use the glue coating equipment to coat the cleaned cover with UV glue; then move the coated cover to the pressing section, and place the vapor-deposited substrate on the upper end of the cover; finally, bond the substrate and cover with the bonding equipment, and complete the light curing of the UV glue at the same time.

[0115] The device structure is as follows:

[0116] .

[0117] Application Example 2-82

[0118] The organic electroluminescent devices of Application Examples 2-82 were prepared according to the above-mentioned method for preparing an organic electroluminescent device, except that the compound 40 in Application Example 1 was replaced with the corresponding compound (as shown in Table 1) to form an electron transport layer.

[0119] Comparative Example 1-Comparative Example 10

[0120] An organic electroluminescent device was prepared according to the above-mentioned method for preparing an organic electroluminescent device, except that the compound 40 in Application Example 1 was replaced by comparative compounds 1 to 10, respectively. The structural formulas of comparative compounds 1 to 10 are as follows:

[0121]

[0122] The driving voltage, luminous efficiency, BI value and lifespan of the organic electroluminescent devices obtained from the above device application examples 1-82 and device comparative examples 1-10 were characterized at a brightness of 1000 (nits). The test results are shown in Table 1 below:

[0123] Table 1. Luminous characteristics test results (brightness value 1000 nits)

[0124]

[0125]

[0126]

[0127] Application Examples 83-138

[0128] Formula I is used as a hole-blocking material to prepare an organic electroluminescent device:

[0129] Application Example 83

[0130] ITO anode: A 150nm thick ITO (indium tin oxide)-Ag-ITO (indium tin oxide) glass substrate was cleaned twice in distilled water, ultrasonically cleaned for 30 minutes, then repeatedly cleaned twice in distilled water, ultrasonically cleaned for 10 minutes, and then baked in a vacuum oven at 220°C for 2 hours. After baking, the substrate was cooled and ready for use. This substrate served as the anode and was deposited using an evaporation device. Other functional layers were then deposited on top.

[0131] b. HIL (hole injection layer): 1 The hole injection layer was formed by vacuum evaporation at a rate of 97:3, with a thickness of 10 nm.

[0132] c. HTL (hole transport layer): 1.5 / s evaporation rate, 130nm HT-2 was vacuum evaporated on the hole injection layer as a hole transport layer, and its chemical formula is shown below;

[0133] d. Prime (luminous auxiliary layer): 0.5 / s evaporation rate, 5nm of prime-1 was vacuum evaporated on the hole transport layer as a light-emitting auxiliary layer, and its chemical formula is as follows;

[0134] e. EML (Emitting Layer): 1 / s, a main material (Host-2) and a dopant material (Dopant-2) with a thickness of 20 nm were vacuum-deposited on the light-emitting auxiliary layer as a light-emitting layer. The chemical formulas of Host-2 and Dopant-2 are shown below. The evaporation rate ratio of Host-2 and Dopant-2 is 98:2.

[0135] f, HB (hole blocking layer): 0.5 / s evaporation rate, 169 with a thickness of 5.0 nm was vacuum evaporated on the light-emitting layer as a hole blocking layer.

[0136] g, ETL (Electron Transport Layer): 1 / s, ET-2 and Liq with a thickness of 30 nm were vacuum evaporated on the hole blocking layer as an electron transport layer, and the evaporation rate ratio of the ET-2 and Liq was 50:50.

[0137] h, EIL (electron injection layer): 0.5 A Yb film with a thickness of 1.0 nm was evaporated on the electron transport layer at a deposition rate of 1.0 nm to form an electron injection layer.

[0138] i. Cathode: 1 / s, magnesium and silver with a thickness of 13 nm were evaporated on the electron injection layer, and the evaporation rate ratio of magnesium to silver was 1:9, to obtain a cathode.

[0139] j. Light extraction layer: 1 / s, and CPL-2 with a thickness of 65 nm was vacuum-deposited on the cathode as a light extraction layer. The chemical formula of CPL is shown below.

[0140] k. Package the vapor-deposited substrate: First, use the glue coating equipment to coat the cleaned cover with UV glue; then move the coated cover to the pressing section, and place the vapor-deposited substrate on the upper end of the cover; finally, bond the substrate and cover with the bonding equipment, and complete the light curing of the UV glue at the same time.

[0141] Device structure:

[0142]

[0143] Application Example 84-138

[0144] The organic electroluminescent devices of Application Examples 84-138 were prepared according to the above-mentioned method for preparing an organic electroluminescent device, except that Compound 169 in Application Example 83 was replaced by a corresponding compound (as shown in Table 2) to form a hole blocking layer.

[0145] Comparative Example 11-Comparative Example 17

[0146] An organic electroluminescent device was prepared according to the above-mentioned method for preparing an organic electroluminescent device, except that the compound 138 in Application Example 84 was replaced by comparative compounds 11 to 17, respectively. The structural formulas of comparative compounds 11 to 17 are as follows:

[0147]

[0148] The driving voltage, luminous efficiency, BI value and lifespan of the organic electroluminescent devices obtained from the above-mentioned device application examples 83-138 and device comparative examples 11-17 were characterized at a brightness of 1000 (nits). The test results are shown in Table 2 below:

[0149] Table 2 Luminous characteristics test results (brightness value is 1000 nits)

[0150]

[0151]

[0152] Those skilled in the art will know that in blue top-emitting devices, the luminous efficiency is greatly affected by chromaticity. Therefore, the influence of chromaticity on efficiency is taken into account, and the ratio of luminous efficiency to CIEy is defined as the BI value, that is, BI = (cd / A) / CIEy.

[0153] The compounds of the present invention are , an alkylfluorenyl group and a triazine side chain are connected thereto. From the data in Table 1 and Table 2, it can be seen that the compound material with the structure represented by Formula I provided by the present invention is used as an electron transport or hole blocking layer in an organic electroluminescent device. Compared with the device prepared by the comparative compound 1-17, the driving voltage, BI and life are all improved.

[0154] Specifically, the difference between comparative compounds 8, 9, and 10 and the present compounds 1, 397, and 87 is that the comparative compounds 8, 9, and 10 are linked to a 9-phenylfluorenyl group, while the present compounds are linked to a 9-alkyl(methyl)fluorene group. The aromatic group of the phenylfluorene in the comparative examples does not act as a conjugator, but instead increases the molecular weight of the compound, leading to higher evaporation temperatures and potentially causing material decomposition, thus affecting device life. The position of the triazine side chain affects the mobility of the side chain, which in turn affects device efficiency.

[0155] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A compound having electron transport function, characterized in that, The compound is any one of the following structures:

2. An organic electroluminescent device, characterized in that: It includes an anode, a cathode and an organic layer arranged between the anode and the cathode; the organic layer includes one or more of a hole injection layer, a hole transport layer, an electron blocking layer, a luminescence auxiliary layer, a luminescent layer, a hole blocking layer, an electron transport layer, an electron injection layer and a capping layer; the hole blocking layer and / or the electron transport layer contains the compound with electron transport function according to any one of claim 1.

3. The organic electroluminescent device according to claim 2, characterized in that: The organic layer is formed by vacuum evaporation or solution coating; the solution coating method includes one or more of spin coating, dip coating, blade coating, inkjet printing, screen printing, spraying and roller coating.

4. The organic electroluminescent device according to claim 2, characterized in that: The material of the hole injection layer includes one or more of metalloporphyrin, oligothiophene, arylamine-based organic material, hexanitrile hexaazatriphenylene-based organic material, quinacridone-based organic material, perylene-based organic material, anthraquinone, and polyaniline-based and polythiophene-based conductive polymers; The material of the hole transport layer includes an arylamine-based organic material, a conductive polymer, or a block copolymer having both a conjugated portion and a non-conjugated portion.

5. Use of the organic electroluminescent device according to any one of claims 2 to 4 in a flat panel display, a computer monitor, a medical monitor, a television, a billboard, a lamp for interior or exterior lighting and / or signaling, a head-up display, a fully transparent or partially transparent display, a flexible display, a laser printer, a telephone, a mobile phone, a tablet, a photo album, a personal digital assistant, a wearable device, a laptop computer, a digital camera, a video camera, a viewfinder, a microdisplay, a three-dimensional display, a virtual reality or augmented reality display, a vehicle, a video wall comprising a plurality of displays tiled together, a theater or stadium screen, a light therapy device and a sign.

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