Compound with biphenyl indoloquinoline structure, preparation method and OLED (Organic Light Emitting Diode) device

Abstract

The invention relates to the technical field of organic electroluminescent material synthesis, in particular to a biphenyl indoloquinoline compound and a preparation method and OLED device application thereof, the structural formula of the biphenyl indoloquinoline compound is as follows: # imgabs0 #, R is substituted or unsubstituted C6-C34 aryl or heterocyclic aryl, R is substituted or unsubstituted C6-C34 aryl or heterocyclic aryl, R is substituted or unsubstituted C6-C34 aryl or heterocyclic aryl, R is substituted or unsubstituted C6-C34 aryl or heterocyclic aryl, R is substituted or unsubstituted C6-C34 aryl or heterocyclic aryl, and R is substituted or unsubstituted C6-C34 aryl or heterocyclic aryl. Heteroatoms in the heterocyclic aryl are selected from at least one of nitrogen, oxygen or sulfur. The biphenyl indoloquinoline compound is applied to the organic electroluminescent device, and an organic layer of the organic electroluminescent device comprises at least one of the biphenyl indoloquinoline compounds. When the bibenzoindoloquinoline compound is applied to an organic light-emitting device, the driving voltage of the OLED device can be reduced, and the light-emitting efficiency and color purity of the device can be improved.

Description

Technical Field

[0001] The present application relates to a compound having a biphenylbenzoindoloquinoline structure, a preparation method thereof, and an OLED device, and belongs to the technical field of OLED materials. Background Art

[0003] With the gradual maturity of OLED display technology, the application of various luminescent materials has also experienced a process of continuous innovation and reform. At present, as the mainstream display, OLED displays have the advantages of being thin, light, high color saturation, fast response speed, active emission, and low energy consumption. OLED display technology is gradually replacing liquid crystal display technology, and the pace is significantly accelerating. Currently, the commercially used OLEDs mainly employ fluorescent materials and phosphorescent materials, each having its own advantages and disadvantages. Although fluorescent materials have good stability, they have low luminous efficiency and high driving voltage. Although phosphorescent materials can significantly improve the device efficiency, they use heavy (expensive) metals, which not only increases the cost but also has poor stability and is difficult to extend the service life of OLED devices. Generally speaking, the short life of OLED devices is one of the key factors affecting their use.

[0004] The core material layers of an OLED device include a light-emitting layer, an electron transport layer, and a hole transport layer. Different material layers require new materials with different structures. According to the requirements of various compounds corresponding to different materials, it is necessary to match the materials of different material layers during the screening process to achieve the ultimate goals of high efficiency, low voltage, and long life. OLED devices have high requirements for charge conduction, luminescence, thermal stability, and luminous efficiency of materials in different layers. Summary of the Invention

[0005] In view of the deficiencies in the prior art, the present invention provides a compound having a biphenylbenzoindoloquinoline structure, a preparation method thereof, and an OLED device. The compound having a biphenylbenzoindoloquinoline structure exhibits excellent performance in OLED devices, having the effects of extending the working life, enhancing the current luminous efficiency, and reducing the driving pressure.

[0006] The technical solution of the present invention for solving the above technical problems is as follows:

[0007] A compound having a biphenylbenzoindoloquinoline structure, the structural formula of the compound is shown as the following general formula 1:

[0008]

[0009] Wherein, R is a substituted or unsubstituted C6-C34 aryl or heteroaryl, and the heteroatoms in the heteroaryl are selected from at least one of nitrogen, oxygen, or sulfur.

[0010] Further, R is selected from any one of substituted or unsubstituted phenyl, naphthyl, biphenyl, polyphenyl, phenanthryl, pyrenyl, fluorenyl, carbazolyl, dibenzofuranyl, dibenzothiophenyl, and triazinyl.

[0011] Further, R is any one of the following structures:

[0012]

[0013]

[0014]

[0015] Among them, * is the connection site.

[0016] Further, the dibenzoindoloquinoline structure compound is any one of the following structures:

[0017]

[0018]

[0019]

[0020]

[0021]

[0022] The present invention also provides a preparation method of the above dibenzoindoloquinoline compound, and the preparation method includes the following steps:

[0023] S1. Preparation of compound a:

[0024] Under nitrogen protection, add 2-bromoquinoline, ammonia water, catalyst cuprous oxide and solvent to a three-necked flask, heat up to 120-130 °C, carry out a distillation reaction, keep warm until the raw materials react completely, and obtain compound a after post-treatment. The structural formula of the compound a is as follows:

[0025]

[0026] S2. Preparation of compound b:

[0027] Under nitrogen protection, add compound a, 2-chloro-3-bromo-8-phenylnaphthalene, sodium tert-butoxide and solvent to a three-necked flask, and add catalyst palladium acetate and catalyst ligand triphenylphosphine. Heat up to 120-130 °C, react while distilling, keep warm until the raw materials react completely, and obtain compound b after post-treatment. The structural formula of the compound b is as follows:

[0028]

[0029] S3. Preparation of intermediate I:

[0030] Under nitrogen protection, compound b, potassium carbonate and solvent are added to a three-necked flask, and catalyst palladium acetate and catalyst ligand tri-tert-butylphosphine tetrafluoroborate are added, and the temperature is raised to 120-130° C., and distillation is performed while reacting. After the heat preservation reaction is completed, intermediate I is obtained by post-treatment. The structural formula of intermediate I is shown below:

[0031]

[0032] S4. Preparation of diphenylindolequinoline structure compounds

[0033] Under nitrogen protection, intermediates I and XR are added into a three-necked flask, and a biphenylindolequinoline structure compound is obtained through coupling reaction, wherein X is any one of Cl, Br, and I, and R is a substituted or unsubstituted C6-C34 aryl or heterocyclic aryl, and the heteroatom in the heterocyclic aryl is selected from at least one of nitrogen, oxygen, or sulfur.

[0034] Furthermore, the solvent of the above steps S1 and S3 is tetrahydrofuran or N,N-dimethylformamide or toluene or dichloromethane, the solvent of step S2 is xylene, and the insulation reaction time of steps S1, S2 and S3 is 16-20 hours.

[0035] Furthermore, in the above step S1, the addition ratio of each reagent is: 2-bromoquinoline: ammonia water = 1 g: 4 ml, cuprous oxide: 2-bromoquinoline = 1 mol: 1 mol, 2-bromoquinoline: solvent = 1 g: 5 ml;

[0036] In step S2, the addition ratio of each reagent is: compound a: 2-chloro-3-bromo-8-phenylnaphthalene: sodium tert-butoxide = 1 mol: 1.1 mol: 3 mol, compound a: solvent = 1 g: 7 ml, catalyst: compound a = 0.01 mol: 1 mol, catalyst: catalyst ligand = 1 mol: 2-3 mol;

[0037] In step S3, the addition ratio of each reagent is: compound b: potassium carbonate = 1 mol: 2.5 mol, catalyst: compound b = 0.01 mol: 1 mol, catalyst: catalyst ligand = 1 mol: 2-3 mol; compound b: solvent = 1 g: 6 ml.

[0038] The present invention also provides application of the biphenylindolequinoline compound, and the biphenylindolequinoline compound can be applied to an organic electroluminescent (OLED) device.

[0039] Furthermore, the biphenylbenzoindoloquinoline compound is used as a light-emitting layer material in an organic electroluminescent (OLED) device. The biphenylbenzoindoloquinoline compound is used as a light-emitting material in OLED lighting and OLED display panels, and the light-emitting material is selected from one or more of a red light-emitting material, a green light-emitting material, and a blue light-emitting material.

[0040] The biphenylbenzoindoloquinoline-structured compound can also be used as a material for an electron transport layer, a light-emitting layer, or a hole transport layer in an OLED device.

[0041] The present invention also provides an organic electroluminescent (OLED) device, and at least one of the above-mentioned biphenylbenzoindoloquinoline-structured compounds is included in the organic layer of the OLED device.

[0042] The beneficial effects of the present invention are as follows:

[0043] The quinoline group is an aromatic heterocyclic compound. Its unique structure contains a heteroatom nitrogen, making it have a stable rigid structure. It is a good electron-rich modification group, making quinoline have stable photothermal properties. Its hole transfer performance and fluorescence emission ability are both very good, and it has excellent optoelectronic properties in OLEDs. Due to the dense electron distribution and close packing of the quinoline group, charge can be efficiently transferred through the form of carriers by jumping directly between the quinoline group and other groups.

[0044] Benefiting from the special structure design of increasing nitrogen heteroatoms and aromatic groups, the biphenylbenzoindoloquinoline structure makes the electron distribution of such quinoline materials denser and the charge transfer more efficient. The novel material with the benzindolobenzquinoline structure has excellent properties in optoelectronic materials.

[0045] When the biphenylbenzoindoloquinoline compound of the present invention is applied to an organic electroluminescent device, it can reduce the driving voltage of the OLED device, improve the light-emitting efficiency, color purity, and service life of the device, and has great application value and commercial value in the application of OLED devices, and has good industrialization prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is a schematic structural diagram of the organic electroluminescent device in the embodiment of the present invention;

[0047] In the figure, 1, transparent substrate layer; 2, transparent anode electrode layer; 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 reflective electrode layer. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0048] The following is a detailed description of the specific embodiments of the present invention. The present invention can be implemented in many other ways different from those described herein. Those skilled in the art can make similar improvements without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed.

[0049] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The terms used are only for describing specific embodiments and are not intended to limit the present invention.

[0050] Example 1

[0051] This example provides a preparation method for a compound having a structure of 1 in the class of biphenylindoloquinoline compounds, which includes the following steps:

[0052]

[0053] The specific synthesis route of Compound 1 is as follows:

[0054] Weigh raw material 1, intermediate I, and sodium tert-butoxide according to a molar ratio of 1.2:1:1.7. Under nitrogen purge, add palladium acetate (2% eq) as a catalyst, intermediate I, anhydrous toluene as a solvent (intermediate I:anhydrous toluene = 1 g:10 mL), sodium tert-butoxide, and raw material 1 to a 250 mL three-necked flask equipped with a magnetic stirrer. React completely at 110 °C for 5 h. Purify by column chromatography to obtain Compound 1. After HPLC detection, there is no remaining intermediate I, the HPLC purity is 99.8%, and the yield is 70%.

[0055] Elemental analysis: C 31 H 20 Theoretical values for C, H, and N2: C, 88.54; H, 4.79; N, 6.66; Measured values: C, 88.41; H, 4.88; N, 6.70; HRMS (ESI) m / z (M+): Theoretical value: 420.163; Measured value: 420.165.

[0056] The preparation process of intermediate I is as follows (the same hereinafter):

[0057] S1. Preparation of Compound a:

[0058] Under nitrogen protection, add 2-bromoquinoline, ammonia water, copper(I) oxide as a catalyst, and a solvent to a three-necked flask. The solvent is tetrahydrofuran or N,N-dimethylformamide or toluene or dichloromethane. The addition ratio of each reagent is: 2-bromoquinoline:ammonia water = 1 g:4 ml, copper(I) oxide:2-bromoquinoline = 1 mol:1 mol, 2-bromoquinoline:solvent = 1 g:5 ml; Heat up to 120 - 130 °C, carry out a distillation reaction, keep warm for 16 - 20 h until the raw materials react completely, and obtain Compound a after post-treatment. The structural formula of the said Compound a is shown as follows:

[0059]

[0060] S2. Preparation of compound b:

[0061] Under nitrogen protection, compound a, 2-chloro-3-bromo-8-phenylnaphthalene, sodium tert-butoxide and solvent are added to a three-necked flask, the solvent is xylene, and catalyst palladium acetate and catalyst ligand triphenylphosphine are added, and the addition ratio of each reagent is: compound a: 2-chloro-3-bromo-8-phenylnaphthalene: sodium tert-butoxide = 1 mol: 1.1 mol: 3 mol, compound a: solvent = 1 g: 7 ml, catalyst: compound a = 0.01 mol: 1 mol, catalyst: catalyst ligand = 1 mol: 2-3 mol; the temperature is raised to 120-130° C., distilled while reacting, and kept warm for 16-20 hours until the raw materials react completely, and compound b is obtained after post-treatment. The structural formula of the compound b is shown as follows:

[0062]

[0063] S3. Preparation of intermediate I:

[0064] Under nitrogen protection, compound b, potassium carbonate and solvent are added to a three-necked flask, the solvent is tetrahydrofuran or N,N-dimethylformamide or toluene or dichloromethane, and catalyst palladium acetate and catalyst ligand tri-tert-butylphosphine tetrafluoroborate are added, and the addition ratio of each reagent is: compound b: potassium carbonate = 1 mol: 2.5 mol, catalyst: compound b = 0.01 mol: 1 mol, catalyst: catalyst ligand = 1 mol: 2-3 mol; compound b: solvent = 1 g: 6 ml; the temperature is raised to 120-130° C., distilled while reacting, and kept warm for 16-20 hours until the reaction is completed, and intermediate I is obtained through post-treatment.

[0065] Example 2

[0066] This embodiment provides a method for preparing a compound having a 3-structure among biphenylindolequinoline compounds, comprising the following steps:

[0067]

[0068] The specific synthetic route of compound 3 is:

[0069] Weigh raw material 3, intermediate I, and sodium tert-butoxide according to a molar ratio of 1:1:2.1. Under nitrogen purge, add palladium acetate (2% eq) as a catalyst, intermediate I, anhydrous toluene as a solvent (intermediate I:anhydrous toluene = 1 g:10 mL), sodium tert-butoxide, and raw material 3 to a 250 mL three-necked flask equipped with a magnetic stirrer. React completely at 110 °C for 5 h. Purify by column chromatography to obtain compound 3. Detection by HPLC shows that there is no remaining intermediate I, the HPLC purity is 99.8%, and the yield is 68%.

[0070] Elemental analysis: C 37 H 24 Theoretical values for N2: C, 89.49; H, 4.87; N, 5.64; Measured values: C, 89.32; H, 4.98; N, 5.70; HRMS (ESI) m / z (M+): Theoretical value: 496.194; Measured value: 496.198.

[0071] Example 3

[0072] This example provides a preparation method for a compound with structure 20 among the dibenzoindoloquinoline compounds, including the following steps:

[0073]

[0074] The specific synthesis route of compound 20 is as follows:

[0075] Weigh raw material 20, intermediate I, and sodium tert-butoxide according to a molar ratio of 1:1:1.8. Under nitrogen purge, add palladium acetate (2% eq) as a catalyst, intermediate I, anhydrous toluene as a solvent (intermediate I:anhydrous toluene = 1 g:10 mL), sodium tert-butoxide, and raw material 20 to a 250 mL three-necked flask equipped with a magnetic stirrer. React completely at 110 °C for 5 h. Purify by column chromatography to obtain compound 20. Detection by HPLC shows that there is no remaining intermediate I, the HPLC purity is 99.9%, and the yield is 68%.

[0076] Elemental analysis: C 44 H 30 Theoretical values for N2: C, 90.07; H, 5.15; N, 4.77; Measured values: C, 89.91; H, 5.27; N, 4.81; HRMS (ESI) m / z (M+): Theoretical value: 586.241; Measured value: 586.243.

[0077] Example 4

[0078] This example provides a preparation method for a compound with structure 25 among the dibenzoindoloquinoline compounds, including the following steps:

[0079]

[0080] The specific synthesis route of Compound 25 is as follows:

[0081] Weigh the raw material 25, intermediate I and sodium tert-butoxide according to the molar ratio of 1:1.1:2. Under nitrogen purge, add the catalyst (2% eq) palladium acetate, intermediate I, the solvent anhydrous toluene (intermediate I:anhydrous toluene = 1 g:10 mL), sodium tert-butoxide and raw material 25 into a 250 mL three-necked flask equipped with a magnetic stirrer. React completely at 110 °C for 5 h. Purify by column chromatography to obtain Compound 25. After HPLC detection, there is no remaining intermediate I, the HPLC purity is 99.8%, and the yield is 70%.

[0082] Elemental analysis: C 50 H 32 The theoretical values of N2 are: C, 90.88; H, 4.88; N, 4.24; The measured values are: C, 90.71; H, 4.98; N, 4.31; HRMS (ESI) m / z (M+): The theoretical value is: 660.257; The measured value is: 660.259.

[0083] Example 5

[0084] This example provides a preparation method for a compound with the structure of 29 in the dibenzoindoloquinoline compounds, including the following steps:

[0085]

[0086] The specific synthesis route of Compound 29 is as follows:

[0087] Weigh the raw material 29, intermediate I and sodium tert-butoxide according to the molar ratio of 1:1:2.1. Under nitrogen purge, add the catalyst (2% eq) palladium acetate, intermediate I, the solvent anhydrous toluene (intermediate I:anhydrous toluene = 1 g:10 mL), sodium tert-butoxide and raw material 29 into a 250 mL three-necked flask equipped with a magnetic stirrer. React completely at 110 °C for 5 h. Purify by column chromatography to obtain Compound 29. After HPLC detection, there is no remaining intermediate I, the HPLC purity is 99.6%, and the yield is 75%.

[0088] Elemental analysis: C 43 H 27 The theoretical values of N3 are: C, 88.18; H, 4.65; N, 7.17; The measured values are: C, 88.06; H, 4.73; N, 7.21; HRMS (ESI) m / z (M+): The theoretical value is: 585.220; The measured value is: 585.223.

[0089] Example 6

[0090] This example provides a preparation method for a compound with the structure of 33 in the dibenzoindoloquinoline compounds, including the following steps:

[0091]

[0092] The specific synthesis route of Compound 33 is as follows:

[0093] Weigh raw material 33, intermediate I, and sodium tert-butoxide according to the molar ratio of 1:1.1:1.8. Under nitrogen purge, add palladium acetate (2% eq) as the catalyst, intermediate I, anhydrous toluene as the solvent (intermediate I:anhydrous toluene = 1 g:10 mL), sodium tert-butoxide, and raw material 33 into a 250 mL three-necked flask equipped with a magnetic stirrer. React completely at 110 °C for 5 h. Purify by column chromatography to obtain Compound 33. After HPLC detection, there is no remaining intermediate I, the HPLC purity is 99.9%, and the yield is 72%.

[0094] Elemental analysis: C 46 H 27 For ON5, theoretical values: C, 82.99; H, 4.09; O, 2.40; N, 10.52; measured values: C, 82.79; H, 4.21; O, 2.42; N, 10.58; HRMS(ESI) m / z (M+): theoretical value: 665.222; measured value: 665.226.

[0095] Example 7

[0096] This example provides a preparation method for a compound with structure 39 among the biphenylbenzoindoloquinoline compounds, including the following steps:

[0097]

[0098] The specific synthesis route of Compound 39 is as follows:

[0099] Weigh raw material 39, intermediate I, and sodium tert-butoxide according to the molar ratio of 1:1.05:1.8. Under nitrogen purge, add palladium acetate (2% eq) as the catalyst, intermediate I, anhydrous toluene as the solvent (intermediate I:anhydrous toluene = 1 g:10 mL), sodium tert-butoxide, and raw material 39 into a 250 mL three-necked flask equipped with a magnetic stirrer. React completely at 110 °C for 5 h. Purify by column chromatography to obtain Compound 39. After HPLC detection, there is no remaining intermediate I, the HPLC purity is 99.9%, and the yield is 70%.

[0100] Elemental analysis: C 52 H 33 For N5, theoretical values: C, 85.81; H, 4.57; N, 9.62; measured values: C, 85.63; H, 4.71; N, 9.66; HRMS(ESI) m / z (M+): theoretical value: 727.274; measured value: 727.277.

[0101] Example 8

[0102] This example provides a method for preparing a compound with a 43 structure among dibenzoindoloquinoline compounds, including the following steps:

[0103]

[0104] The specific synthesis route of compound 43 is as follows:

[0105] Weigh raw material 43, intermediate I, and sodium tert-butoxide according to a molar ratio of 1:1.1:1.8. Under nitrogen purge, add catalyst (2% eq) palladium acetate, intermediate I, solvent anhydrous toluene (intermediate I:anhydrous toluene = 1 g:10 mL), sodium tert-butoxide, and raw material 43 to a 250 mL three-necked flask equipped with a magnetic stirrer. React completely at 110 °C for 5 h. Purify by column chromatography to obtain compound 43. Detect by HPLC. There is no remaining intermediate I. The HPLC purity is 99.9%, and the yield is 68%.

[0106] Elemental analysis: C 50 H 31 Theoretical values for C, H, and N5: C, 85.57; H, 4.45; N, 9.98; Measured values: C, 85.41; H, 4.55; N, 10.04; HRMS(ESI) m / z(M+): Theoretical value: 701.258; Measured value: 701.261.

[0107] Example 9

[0108] This example provides a method for preparing a compound with a 44 structure among dibenzoindoloquinoline compounds, including the following steps

[0109]

[0110] The specific synthesis route of compound 44 is as follows:

[0111] Weigh raw material 44, intermediate I, and sodium tert-butoxide according to a molar ratio of 1:1.1:2. Under nitrogen purge, add catalyst (2% eq) palladium acetate, intermediate I, solvent anhydrous toluene (intermediate I:anhydrous toluene = 1 g:10 mL), sodium tert-butoxide, and raw material 44 to a 250 mL three-necked flask equipped with a magnetic stirrer. React completely at 110 °C for 5 h. Purify by column chromatography to obtain compound 44. Detect by HPLC. There is no remaining intermediate I. The HPLC purity is 99.8%, and the yield is 72%.

[0112] Elemental analysis: C 52 H 31ON5 theoretical values: C, 84.19; H, 4.21; O, 2.16; N, 9.44; measured values: C, 84.02; H, 4.31; O, 2.19; N, 9.48; HRMS(ESI) m / z(M+): theoretical value: 741.253; measured value: 741.256.

[0113] Example 10

[0114] This example provides a preparation method for a compound with a 48 structure in biphenylbenzoindoloquinoline compounds, including the following steps:

[0115]

[0116] The specific synthesis route of compound 48 is as follows:

[0117] Weigh raw material 48, intermediate I and sodium tert-butoxide according to a molar ratio of 1:1:2. Under nitrogen purge, add catalyst (2% eq) palladium acetate, intermediate I, solvent anhydrous toluene (intermediate I: anhydrous toluene = 1 g: 10 mL), sodium tert-butoxide and raw material 48 to a 250 mL three-necked flask equipped with a magnetic stirrer. React completely at 110 °C for 5 h. Purify by column chromatography to obtain compound 25. Detection by HPLC shows that there is no remaining intermediate I, the HPLC purity is 99.8%, and the yield is 70%.

[0118] Elemental analysis: C 59 H 37 N5 theoretical values: C, 86.85; H, 4.57; N, 8.58; measured values: C, 86.64; H, 4.71; N, 8.65; HRMS(ESI) m / z(M+): theoretical value: 815.305; measured value: 815.308.

[0119] Device example:

[0120] The structure of the OLED light-emitting device is as Figure 1 shown. Deposit a hole injection layer (HIL) on a transparent conductive glass or plastic substrate or a substrate coated with indium-tin oxide ITO, and then sequentially pass through a hole transport layer (HTL), a light-emitting layer (EML), an electron transport layer (ETL) and an electron injection layer (EIL). Finally, add a metal layer as a conductive cathode and a sealing ring. The present invention relates to a biphenylbenzoindoloquinoline structure compound, which is a novel material with excellent electron and hole transport properties and light emission performance. The following device examples take a novel material with a benzoindolebenzoquinoline structure as the light-emitting layer as an example to study the device performance.

[0121] Device example 1:

[0122] The transparent anode electrode layer 2 (with a film thickness of 209 nm, indium tin oxide) on the transparent substrate layer 1 is processed as follows: First, photolithography and etching are performed to form the required regular transparent anode electrode layer 2. Immediately afterwards, the transparent substrate layer 1 is washed, that is, alkali washing, deionized water washing, acetone ultrasonic cleaning, ethanol ultrasonic cleaning, ultrapure water cleaning, and drying are carried out in sequence. Then, ultraviolet-ozone washing is performed on the transparent anode electrode layer 2 to ensure the removal of organic residues on the surface of the transparent anode electrode layer 2. After the above washing treatment, a hole injection layer 3 is evaporated on the transparent anode electrode layer 2. Using a vacuum evaporation device, the material shown in Structural Formula 1 is evaporated (molybdenum crucible, evaporation rate 0.1 nm / s, vacuum degree 4.0*10 -5 Pa), and the evaporated film thickness is 56 nm. This organic material is used as the hole injection layer 3. Immediately afterwards, a material shown in Structural Formula 2 with a thickness of 24 nm is evaporated on the hole injection layer 3 as the hole transport layer 4, and a material shown in Structural Formula 3 with a thickness of 20 nm is evaporated on the hole transport layer 4 as the electron blocking layer 5. After the evaporation of the electron blocking layer 5 is completed, the material shown in Compound 1 and Ir(ppy)3 are evaporated onto the electron blocking layer 5 at a weight ratio of 94:6 (molybdenum crucible, evaporation rate 0.1 nm / s, vacuum degree 4.0*10 -5 Pa) to obtain the light-emitting layer 6, and the film thickness of the light-emitting layer 6 is 31 nm.

[0123] On the light-emitting layer 6, a material shown in Structural Formula 5 is vacuum-evaporated as the hole blocking layer 7 (molybdenum crucible, evaporation rate 0.1 nm / s, vacuum degree 4.0*10 -5 Pa), and the vacuum-evaporated film thickness is 20 nm. After the evaporation of the hole blocking layer 7 is completed, a material shown in Structural Formula 6 is evaporated on the hole blocking layer 7 to obtain the electron transport layer 8, and the evaporated film thickness is 79 nm. On the electron transport layer 8, a 0.8 nm thick lithium fluoride (LiF) layer is fabricated through a vacuum evaporation device to obtain the electron injection layer 9.

[0124] The cathode reflective electrode layer 10 is prepared by vacuum evaporation on the electron injection layer 9 to form an aluminum (Al) layer with a film thickness of 145 nm.

[0125] Device Examples 2 to 9:

[0126] The differences between Examples 2 to 9 and Device Example 1 are as follows: The host material of the light-emitting layer of the electroluminescent device is Compound 3, 20, 25, 29, 33, 39, 43, 44 of the present invention.

[0127] Comparative Example 1

[0128] The difference between this example and Device Example 1 is as follows: The host material of the light-emitting layer of the electroluminescent device is Compound α.

[0129] The structural formula of α is as follows:

[0130]

[0131] Comparative Example 2

[0132] The difference between this example and Device Example 1 is that the host material of the light-emitting layer of the electroluminescent device is Compound β, and the structural formula of Compound β is as follows:

[0133]

[0134] Comparative Example 3

[0135] The difference between this example and Device Example 1 is that the host material of the light-emitting layer of the electroluminescent device is Compound γ, and the structural formula of Compound γ is as follows:

[0136]

[0137] The performance test data of the OLED devices of Device Examples 1-9 and Comparative Examples 1-2 are shown in Table 1:

[0138] Table 1 Performance Test Data of OLED Devices

[0139] Device Host material of light-emitting layer Color Driving voltage (V) Luminous efficiency (cd / A) Lifetime (LT95%) Comparative Example 1 Compound α Green 4.58 72.9 362 Comparative Example 2 Compound β Green 4.72 80.5 385 Comparative Example 3 Compound γ Green 4.89 81.3 398 Device Example 1 Compound 1 Green 3.12 92.7 725 Device Example 2 Compound 3 Green 3.05 96.5 712 Device Example 3 Compound 20 Green 2.98 96.5 696 Device Example 4 Compound 25 Green 2.99 97.6 699 Device Example 5 Compound 29 Green 3.06 94.9 716 Device Example 6 Compound 33 Green 2.96 96.8 689 Device Example 7 Compound 39 Green 3.27 97.8 742 Device Example 8 Compound 43 Green 3.22 96.5 731 Device Example 9 Compound 44 Green 2.96 97.8 686

[0140] Note: When testing the above OLED devices, a forward DC voltage was applied, and the organic electroluminescent characteristics were measured using a PR-650 photometric measurement device from Photo Research. The lifetime of T95 was measured using a lifetime measurement device from McScience at a reference gray level of 5000 nits.

[0141] It can be seen from the test results in the above table that the OLED devices applying the biphenylbenzoindoloquinoline structure compounds involved in the present invention generally have a long operating lifetime, a low driving voltage, and an improved current luminous efficiency compared with the devices prepared from Compound α, Compound β, or Compound γ. In summary, the OLED devices prepared from the biphenylbenzoindoloquinoline structure compounds involved in the present invention have excellent performance in all aspects.

[0142] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, all possible combinations of the technical features in the above embodiments are not exhaustively listed. However, as long as there is no contradiction in the combination of these technical features, it should be considered to be within the scope described in this specification.

[0143] For those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. The protection scope of the present invention is subject to the appended claims.

Claims

1. A biphenylindolequinoline structure compound, characterized in that: The compound structural formula is shown in the following general formula 1: Wherein, R is selected from any one of the following structural formulas: Among them, * is the connection site.

2. The biphenylindolequinoline structure compound according to claim 1, characterized in that: The compound is any one of the following structures:

3. A method for preparing a biphenylindolequinoline structure compound as claimed in claim 1 or 2, characterized in that: The preparation method comprises the following steps: S1. Preparation of compound a: Under nitrogen protection, 2-bromoquinoline, ammonia water, catalyst cuprous oxide and solvent were added to a three-necked flask, the temperature was raised to 120-130°C, distillation reaction was carried out, and the temperature was kept until the raw materials reacted completely. After post-treatment, compound a was obtained. The structural formula of the compound a is shown below: S2. Preparation of compound b: Under nitrogen protection, compound a, 2-chloro-3-bromo-8-phenylnaphthalene, sodium tert-butoxide and solvent were added to a three-necked flask, and catalyst palladium acetate and catalyst ligand triphenylphosphine were added, and the temperature was raised to 120-130° C., and distillation was carried out while reacting. The temperature was kept until the raw materials reacted completely, and compound b was obtained after post-treatment. The structural formula of the compound b is shown below: S3. Preparation of intermediate I: Under nitrogen protection, compound b, potassium carbonate and solvent are added to a three-necked flask, and catalyst palladium acetate and catalyst ligand tri-tert-butylphosphine tetrafluoroborate are added, and the temperature is raised to 120-130° C., and distillation is performed while reacting. After the heat preservation reaction is completed, intermediate I is obtained by post-treatment. The structural formula of intermediate I is shown below: S4. Preparation of diphenylindolequinoline structure compounds Under nitrogen protection, intermediate I and XR are added into a three-necked flask, and a biphenylindolequinoline structure compound is obtained through coupling reaction, wherein X is any one of Cl, Br, and I, and R is as described in claim 1 or 2.

4. The method for preparing a biphenylindolequinoline structure compound according to claim 3, characterized in that: The solvent of steps S1 and S3 is tetrahydrofuran or N,N-dimethylformamide or toluene or dichloromethane, the solvent of step S2 is xylene, and the insulation reaction time of steps S1, S2 and S3 is 16-20 hours.

5. The method for preparing a biphenylindolequinoline structure compound according to claim 3, characterized in that: In step S1, the addition ratio of each reagent is: 2-bromoquinoline: ammonia water = 1 g: 4 ml, cuprous oxide: 2-bromoquinoline = 1 mol: 1 mol, 2-bromoquinoline: solvent = 1 g: 5 ml; In step S2, the addition ratio of each reagent is: compound a: 2-chloro-3-bromo-8-phenylnaphthalene: sodium tert-butoxide = 1 mol: 1.1 mol: 3 mol, compound a: solvent = 1 g: 7 ml, catalyst: compound a = 0.01 mol: 1 mol, catalyst: catalyst ligand = 1 mol: 2-3 mol; In step S3, the addition ratio of each reagent is: compound b: potassium carbonate = 1 mol: 2.5 mol, catalyst: compound b = 0.01 mol: 1 mol, catalyst: catalyst ligand = 1 mol: 2-3 mol; Compound b: solvent = 1 g: 6 ml.

6. A use of the biphenylindolequinoline structure compound as claimed in claim 1 or 2, characterized in that: The biphenylindolequinoline structure compound can be applied to OLED devices.

7. The use of the biphenylindolequinoline structure compound according to claim 6, characterized in that: The biphenylindolequinoline structure compound is used as a light-emitting layer, an electron transport layer, a light-emitting layer or a hole transport layer material of an OLED device.

8. An OLED device, characterized in that: The organic layer of the OLED device comprises at least one biphenylindolequinoline structure compound as claimed in claim 1 or 2.

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