OLED light-emitting layer guest material based on D-A type nitrogen heterocyclic gallium compound and application of OLED light-emitting layer guest material

Abstract

The invention provides an OLED luminescent layer guest material based on a D-A type nitrogen-containing heterocyclic gallium compound and application thereof, the compound is a D-A type nitrogen-containing ligand gallium (Ga) compound as shown in formula (I), the ligand is a D-A type structure composed of an NH-containing electron donating group and an N-containing electron withdrawing group, and the ligand has great influence on material performance; the light-emitting property of the Ga compound does not depend on metal atoms, light emission is enhanced through the multi-quantum-state coupling effect of multiple ligands, the light-emitting wavelength of the gallium compound can be effectively regulated and controlled by adopting the ligands with large charge transfer amount and large array intensity, and the light-emitting efficiency of the gallium compound is improved. Therefore, good luminous efficiency, light stability and service life can be realized in the organic electroluminescent device; the Ga compound is relatively simple in structure and relatively low in molecular weight, the synthesis cost and difficulty are reduced, and the evaporation temperature is relatively low. # imgabs0 #

Description

Technical Field

[0001] The present application relates to the technical field of organic light-emitting display, and particularly to an OLED light-emitting layer host material based on a D-A type nitrogen-containing heterocyclic gallium complex and its application. Background Art

[0002] An organic electroluminescent device includes an anode, a cathode, and an organic functional layer disposed between the anode and the cathode, including a light-emitting layer. A hole transport region may exist between the anode and the light-emitting layer, and an electron transport region may exist between the light-emitting layer and the cathode. Holes from the anode can migrate to the light-emitting layer through the hole transport region, and electrons from the cathode can migrate to the light-emitting layer through the electron transport region. After the OLED (organic electroluminescent display) device is powered on, electrons and holes from the cathode and anode migrate to the light-emitting layer to recombine into excitons, exciting the electrons of the host material to reach the excited state. The high-energy host material molecules transfer energy to the guest molecules by means of energy transfer. After the guest molecules are excited to the excited state, they release the excess energy in the form of light and return to the ground state, and the cycle continues.

[0003] As a new type of display technology, organic electroluminescent devices have unique advantages such as self-luminescence, wide viewing angle, low energy consumption, high efficiency, thinness, rich colors, fast response speed, wide applicable temperature range, low driving voltage, and can be used to fabricate flexible, bendable, and transparent display panels and are environmentally friendly, and can be applied to flat panel displays and new generation lighting. Since the end of the 1980s, organic electroluminescent devices have been industrially applied, such as being used as the screens of cameras and mobile phones, etc. However, the current OLED devices are restricted from being more widely applied due to factors such as low efficiency and short service life, especially for large-screen displays. Since the organic electroluminescent materials are prone to crystallization when the OLED device is operating under voltage, which affects the life and efficiency of the OLED device, therefore, it is necessary to develop stable and efficient organic electroluminescent materials. Summary of the Invention

[0004] The purpose of the present application is to provide a compound, which can improve the luminous efficiency, light stability, and extend the service life of the organic electroluminescent device when used as a light-emitting layer host material. The specific technical solutions are as follows:

[0005] The first aspect of the present application provides a compound represented by formula (I):

[0006]

[0007] Wherein, R 1 、R 2 are each independently selected from hydrogen, deuterium, halogen, unsubstituted or Ra-substituted C 1- C10 Alkyl, C which is unsubstituted or substituted by Ra 3- C 10 Cycloalkyl, C which is unsubstituted or substituted by Ra 6- C 14 Aryl, C which is unsubstituted or substituted by Ra 2- C 14 Heteroaryl, C which is unsubstituted or substituted by Ra 1- C 10 Alkoxy, amino which is unsubstituted or substituted by Ra, where each Ra is independently selected from fluorine, deuterium, methyl or tert-butyl; the heteroatoms on the heteroaryl are each independently selected from N, O, S;

[0008] Ring A is selected from a five-membered ring group containing N or a six-membered ring group containing N; Y 1 is selected from =O, p is selected from 0 or 1; Y 2 is selected from C 1- C 10 alkyl, q is selected from 0 or 1;

[0009] Ring B is selected from being absent or C 6- C 18 aryl; Y 3 is selected from C 1- C 10 alkyl, r is selected from 0 or 1;

[0010] X 1 , X 2 , X 3 , X 4 are each independently selected from hydrogen, C 1- C 10 hydrocarbyl, X 1 , X 2 , X 3 , X 4 two adjacent groups among them can be connected to form a six-membered ring which is unsubstituted or substituted by C 1- C 3 alkyl;

[0011] n is selected from 1, 2 or 3.

[0012] In some embodiments of the present application, R 1 , R 2 are each independently selected from hydrogen, halogen, C 1- C 6 alkyl which is unsubstituted or substituted by fluorine.

[0013] In some embodiments of the present application, ring A is selected from

[0014] In some embodiments of the present application, ring B is selected from being absent,

[0015] In some embodiments of the present application, the structural unit is selected from

[0016] In some embodiments of the present application, the structural unit is selected from

[0017] In some embodiments of the present application, the compound is a compound represented by formula (IIa), formula (IIb), formula (IIc) or formula (IId):

[0018]

[0019] In some embodiments of the present application, the compound is selected from the following compounds:

[0020]

[0021]

[0022]

[0023] The second aspect of the present application provides an organic light-emitting material, which comprises at least one of the compounds provided in the first aspect of the present application.

[0024] The third aspect of the present application provides an organic electroluminescent device, which comprises at least one of the organic light-emitting materials provided in the second aspect of the present application.

[0025] In some embodiments of the present application, the organic light-emitting material is used as a blue light host material.

[0026] The fourth aspect of the present application provides a display device, which comprises the organic electroluminescent device provided in the third aspect of the present application.

[0027] Advantages of the present application:

[0028] The compound provided by the present application is a D-A type nitrogen-containing ligand gallium (Ga) complex. The ligand has a D-A type structure composed of an NH-containing electron-donating group and an N-containing electron-withdrawing group, and this ligand has a great influence on the material properties; the luminescence property of the Ga complex does not depend on metal atoms, but the multi-quantum state coupling effect of multiple ligands enhances luminescence. By using ligands with a large charge transfer amount and a large oscillator strength, the luminescence wavelength of the gallium complex can be effectively regulated, so that good luminescence efficiency, light stability and service life can be achieved in organic electroluminescent devices; the structure of the Ga complex is relatively simple and the molecular weight is low, which reduces the synthesis cost and difficulty, and the evaporation temperature is also low. The organic electroluminescent device of the present application contains the compound of the present application as a blue light-emitting guest material, which can improve the luminescence efficiency and light stability and extend the service life of the organic electroluminescent device. The display device provided by the present application has excellent display effects.

[0029] Of course, it is not necessary for any product or method implementing the present application to simultaneously achieve all the above-mentioned advantages. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present application, and those of ordinary skill in the art can also obtain other embodiments according to these drawings.

[0031] Figure 1 It is a schematic structural diagram of a typical organic electroluminescent device. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0032] The following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, rather than all embodiments. All other embodiments obtained by those skilled in the art based on the present application belong to the scope of protection of the present application.

[0033] The first aspect of the present application provides a compound represented by formula (I):

[0034]

[0035] Wherein, R 1 , R 2 are each independently selected from hydrogen, deuterium, halogen, C 1- C 10 alkyl which is unsubstituted or substituted by Ra, C 3- C 10 cycloalkyl which is unsubstituted or substituted by Ra, C6- C 14 Aryl, or C unsubstituted or substituted by Ra 2- C 14 Heteroaryl, or C unsubstituted or substituted by Ra 1- C 10 Alkoxy, or amino unsubstituted or substituted by Ra, where each Ra is independently selected from fluorine, deuterium, methyl, or tert-butyl; the heteroatoms on the heteroaryl are each independently selected from N, O, S;

[0036] Ring A is selected from a five-membered ring group containing N or a six-membered ring group containing N; Y 1 is selected from =O, p is selected from 0 or 1; Y 2 is selected from C 1- C 10 alkyl, q is selected from 0 or 1;

[0037] Ring B is selected from absent or C 6- C 18 aryl; Y 3 is selected from C 1- C 10 alkyl, r is selected from 0 or 1;

[0038] X 1 、X 2 、X 3 、X 4 are each independently selected from hydrogen, C 1- C 10 hydrocarbyl, and two adjacent groups among X 1 、X 2 、X 3 、X 4 can be connected to form a six-membered ring unsubstituted or substituted by C 1- C 3 alkyl;

[0039] n is selected from 1, 2, or 3.

[0040] The C 1- C 10 hydrocarbyl described in this application can be a saturated hydrocarbyl or an unsaturated hydrocarbyl, that is, containing one or more alkenyl or alkynyl groups.

[0041] In some embodiments of this application, R 1 、R 2 are each independently selected from hydrogen, halogen, or C unsubstituted or substituted by fluorine 1- C 6 alkyl.

[0042] In some embodiments of this application, ring A is selected from

[0043] In some embodiments of the present application, ring B is selected from absent,

[0044] In some embodiments of the present application, the structural unit is selected from

[0045] In some embodiments of the present application, the structural unit is selected from

[0046] In some embodiments of the present application, the compound is a compound represented by formula (IIa), formula (IIb), formula (IIc) or formula (IId):

[0047]

[0048] For example, the compound of general formula (I) can be selected from the compounds represented by the following G1 to G20:

[0049]

[0050]

[0051]

[0052]

[0053] The compound of general formula (I) provided by the present application is a D-A type nitrogen-containing ligand Ga complex. The ligands are all D-A type structures composed of an NH-containing electron-donating group and an N-containing electron-withdrawing group. This ligand has a great influence on the material properties; the luminescence property of the Ga complex does not depend on metal atoms, but the multi-quantum state coupling effect of multiple ligands enhances luminescence. By using ligands with large charge transfer amount and large oscillator strength, the luminescence wavelength of the gallium complex can be effectively regulated, so that good luminescence efficiency, light stability and service life can be achieved in organic electroluminescent devices; the Ga complex has a relatively simple structure and a low molecular weight, which reduces the synthesis cost and difficulty, and has a low evaporation temperature.

[0054] The second aspect of the present application provides an organic light-emitting material, which contains at least one of the compounds provided by the present application.

[0055] When the organic light-emitting material of the present application is applied in a light-emitting layer, it exhibits good luminescence efficiency and light stability, and can extend its service life when used in an organic electroluminescent device.

[0056] The third aspect of the present application provides an organic electroluminescent device, which includes at least one of the organic light-emitting materials provided by the present application. Therefore, the organic electroluminescent device provided by the present application has good luminous efficiency, light stability, and service life.

[0057] Preferably, the organic light-emitting material of the present application is used as a blue light host material in the organic electroluminescent device.

[0058] In the present application, there is no particular limitation on the type and structure of the organic electroluminescent device, and it can be various types and structures of organic electroluminescent devices well-known in the art, as long as the organic light-emitting materials provided by the present application can be used.

[0059] The organic electroluminescent device of the present application can be a top-emitting structure light-emitting device, for example, it can include an anode, a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, an electron injection layer, and a transparent or semi-transparent cathode in sequence on a substrate.

[0060] The organic electroluminescent device of the present application can also be a bottom-emitting structure light-emitting device, for example, it can include a transparent or semi-transparent anode, a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, an electron injection layer, and a cathode structure in sequence on a substrate.

[0061] The organic electroluminescent device of the present application can also be a double-sided emission structure light-emitting device, for example, it can include a transparent or semi-transparent anode, a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, an electron injection layer, and a transparent or semi-transparent cathode structure in sequence on a substrate.

[0062] The organic electroluminescent device of the present application can also be provided with an electron blocking layer between the hole transport layer and the light-emitting layer, a hole blocking layer between the light-emitting layer and the electron transport layer, and a light extraction layer on the transparent electrode of the light-emitting layer. However, the structure of the organic electroluminescent device of the present application is not limited to the above specific structures, and in actual applications, these layers can be added or omitted according to specific circumstances. The present application has no particular limitation on the thickness of the above-mentioned layers, as long as the purpose of the present application can be achieved. For example, the organic electroluminescent device can include an anode electrode, a hole injection layer (5 - 20 nm), a hole transport layer (80 - 140 nm), an electron blocking layer (5 - 20 nm), a light-emitting layer (150 - 400 nm), a hole blocking layer (5 - 20 nm), an electron transport layer (300 - 800 nm), an electron injection layer (5 - 20 nm), a transparent cathode electrode, and a light extraction layer (50 - 90 nm) in sequence on a substrate.

[0063] Figure 1The figure shows a schematic diagram of a typical organic electroluminescent device, in which, from bottom to top, a substrate 1, a reflective anode electrode 2, a hole injection layer 3, a hole transport layer 4, a light-emitting layer 5, an electron transport layer 6, an electron injection layer 7, and a cathode electrode 8 are sequentially arranged.

[0064] It can be understood that Figure 1 only a typical structure of an organic electroluminescent device is schematically shown, and the present application is not limited to this structure. The organic light-emitting materials of the present application can be used in any type of organic electroluminescent device.

[0065] For convenience, the organic electroluminescent device of the present application will be described below with reference to Figure 1 This does not mean any limitation to the protection scope of the present application. It can be understood that all organic electroluminescent devices that can use the organic light-emitting materials of the present application are within the protection scope of the present application.

[0066] In the present application, the substrate 1 is not particularly limited, and conventional substrates used in organic electroluminescent devices in the prior art can be used, for example, glass, polymer materials, and glass and polymer materials with thin-film transistor (TFT) components, etc.

[0067] In the present application, the reflective anode material 2 is not particularly limited and can be selected from transparent conductive materials known in the prior art such as indium tin oxide (ITO), indium zinc oxide (IZO), tin dioxide (SnO 2 ), zinc oxide (ZnO), etc., or can be selected from metal materials such as silver and its alloys, aluminum and its alloys, etc., or can also be selected from organic conductive materials such as poly(3,4-ethylenedioxythiophene) (PEDOT), or multi-layer structures of the above materials, etc.

[0068] In the present application, the material of the hole injection layer 3 is not particularly limited and can be made of hole injection layer materials well-known in the art. For example, at least one of the known hole transport materials (HTM) is selected as the hole injection material.

[0069] In the present application, the hole injection layer 3 may further include a p-type dopant. The type of the p-type dopant is not particularly limited, and various p-type dopants known in the art can be used. For example, the p-type dopant can be selected from but not limited to at least one of the following compounds p-1 to p-3:

[0070]

[0071] In the present application, the dosage of the p-type dopant is not particularly limited and can be the dosage well-known to those skilled in the art.

[0072] In the present application, the material of the hole transport layer 4 is not particularly limited and can be made of hole transport materials (HTM) well-known in the art. The number of layers of the hole transport layer 4 is not particularly defined and can be adjusted according to actual needs as long as the purpose of the present application can be satisfied. For example, it can be 1 layer, 2 layers, 3 layers, 4 layers or more layers.

[0073] For example, the HTM for the hole injection layer material and the HTM for the hole transport layer material can be selected from but not limited to at least one of the following compounds HT-1 to HT-31:

[0074]

[0075]

[0076]

[0077] In the present application, the material of the light-emitting layer 5 includes a host material and a guest material. The host material can include at least one of the known host materials.

[0078] For example, the known host materials can be selected from but not limited to at least one of the following compounds BH-1 to BH-10:

[0079]

[0080] In the present application, the guest material can include at least one of the organic light-emitting materials of the present application, or can include a combination of at least one of the organic light-emitting materials of the present application and at least one of the known guest materials of the light-emitting layer in the art.

[0081] For example, the known guest materials of the light-emitting layer can be selected from but not limited to at least one of the following compounds BD-1 to BD-9:

[0082]

[0083] In the present application, the dosage of the guest material of the light-emitting layer is not particularly limited and can be the dosage well-known to those skilled in the art.

[0084] In the present application, the material of the electron transport layer 6 is not particularly limited and can use the electron transport materials known in the art. The number of layers of the electron transport layer 6 is not particularly defined and can be adjusted according to actual needs as long as the purpose of the present application can be satisfied. For example, it can be 1 layer, 2 layers, 3 layers, 4 layers or more layers.

[0085] For example, the known electron transport materials can be selected from but not limited to at least one of the following compounds ET-1 to ET-57:

[0086]

[0087]

[0088]

[0089]

[0090] In the present application, the electron transport layer 6 may further include an n-type dopant. The type of the n-type dopant is not particularly limited, and various n-type dopants known in the art can be used. For example, the following n-type dopants can be used:

[0091]

[0092] In the present application, the dosage of the n-type dopant is not particularly limited and can be a dosage known to those skilled in the art.

[0093] In the present application, the material of the electron injection layer 7 is not particularly limited, and known electron injection materials in the art can be used. For example, it may include but is not limited to LiQ, LiF, NaCl, CsF, Li 2 O, Cs 2 CO 3 , BaO, Na, Li, Ca and other materials.

[0094] In the present application, the material of the cathode electrode 8 is not particularly limited and can be selected from but not limited to metal, metal mixture, oxide such as magnesium-silver mixture, LiF / Al, ITO, Al, etc.

[0095] The method for preparing the organic electroluminescent device of the present application is not particularly limited, and any method known in the art can be used. For example, the present application can be prepared by the following preparation method:

[0096] (1) Clean the reflective anode electrode 2 on the top-emitting OLED device substrate 1, and perform steps such as chemical washing, water washing, brushing, high-pressure water washing, air knife in a cleaning machine, and then perform heat treatment;

[0097] (2) Vacuum deposit a hole injection material on the reflective anode electrode 2 as the hole injection layer 3;

[0098] (3) Vacuum deposit a hole transport material on the hole injection layer 3 as the hole transport layer 4;

[0099] (4) Vacuum deposit a light-emitting layer 5 on the hole transport layer 4, and the light-emitting layer 5 contains a host material and a guest material;

[0100] (5) Vacuum deposit an electron transport material on the light-emitting layer 5 as the electron transport layer 6;

[0101] (6) Vacuum-evaporate an electron injection material on the electron transport layer 6 as the electron injection layer 7;

[0102] (7) Vacuum-evaporate a cathode material on the electron injection layer 7 as the cathode electrode 8.

[0103] The above only describes the structure and preparation method of a typical organic electroluminescent device. It should be understood that the present application is not limited to this structure. The organic light-emitting materials of the present application can be used in organic electroluminescent devices of any structure, and any preparation method known in the art can be used to prepare the organic electroluminescent devices.

[0104] The fourth aspect of the present application provides a display device, which includes the organic electroluminescent device provided by the present application. The display device includes, but is not limited to, a display, a television, a tablet computer, a mobile communication terminal, etc.

[0105] There is no particular limitation on the synthesis method of the compounds of the present application, and any method known to those skilled in the art can be used for synthesis. The following is an example to illustrate the synthesis process of the compounds of the present application.

[0106] Synthesis Example

[0107] Synthesis Example 1: Synthesis of Compound G1

[0108]

[0109] Weigh o-phenylenediamine (1.0 mmol) and pyridine-2-carboxaldehyde (1.1 mmol) into a three-necked flask, add 40 mL of water, heat and reflux at 100 °C for 12 h, monitor the reaction progress by TLC (thin layer chromatography) (dichloromethane: MeOH = 9:1, v:v), after the reaction is completed, cool the reaction mixture to room temperature, filter to collect the product, wash the filtrate with water and drain it, and recrystallize the residue with ethanol and dichloromethane (DCM) multiple times to obtain the product 2-(2'-pyridyl)benzimidazole as a white solid powder (yield: 57%). 1 H NMR (400 MHz, d6-DMSO): δ = 13.10 (br, 1H), 8.73 (d, J = 3.2 Hz, 1H), 8.33 (d, J = 7.6 Hz, 1H), 8.00 (t, J = 7.2 Hz, 1H), 7.71 (d, J = 7.6 Hz, 1H), 7.55 - 7.52 (m, 2H), 7.26 - 7.19 (m, 2H).

[0110] Triethylamine (24.2 mmol), 2-(2'-pyridyl)benzimidazole (24.2 mmol) and MeOH (20 mL) solution were mixed in a 100 mL three-necked flask. The whole system was evacuated and purged with nitrogen, and then stirred at room temperature for 30 minutes. A mixed solution of Ga(NO 3 ) 3 .xH 2 O (7.8 mmol, CAS No: 69365-72-6) and MeOH (5 mL) was added, and the system was refluxed (70 °C) overnight under an inert atmosphere. After the reaction was completed, the mixture was cooled to room temperature (25 °C), and then extracted with dichloromethane. The combined organic layers were washed with brine and dried over MgSO 4 . The solvent was removed by a rotary evaporator. The crude product was purified by silica gel column chromatography, and the eluents were successively: ethyl acetate:dichloromethane = 1:1 (v:v), methanol:dichloromethane = 1:30 (v:v), to obtain a white solid G1 (yield: 37%). 1 H NMR (600 MHz, Chloroform-d) δ 8.72 (s, 1H), 8.65 (dd, J = 17.9, 6.1 Hz, 2H), 8.13 (s, 2H), 8.06 (s, 1H), 7.81 (t, J = 11.5 Hz, 3H), 7.64 (s, 1H), 7.56 (s, 1H), 7.36 (d, J = 13.6 Hz, 3H), 7.25–7.21 (m, 1H), 7.12 (s, 3H), 6.86 (s, 2H), 6.77 (s, 1H), 6.02 (d, J = 12.1 Hz, 1H), 5.94 (s, 1H), 5.91 (s, 1H). MS (MALDI-TOF) m / z [M+H] + calcd. For GaC 31 H 22 N 9 651.14, found 651.35.

[0111] Synthesis Example 2: Synthesis of Compound G3

[0112]

[0113] A mixture of isoquinoline-1-carboxylic acid (1 mmol), 1,2-phenylenediamine (1.2 mmol) and polyphosphoric acid (20 mL) was heated at 180 °C for 6 h in nitrogen. The reaction mixture was cooled to 80 °C, deionized water (500 mL) was added under stirring, and the mixture was filtered. The residue was washed with water (100 mL). The crude product was purified by silica gel column chromatography, and the eluent was ethyl acetate:dichloromethane = 2:1 (v:v), to obtain a white solid powder, i.e., the ligand compound 2-(2'-isoquinolyl)benzimidazole (yield: 37%). 1 HNMR (400 MHz, DMSO-d6): δ 13.27 (s, 1H), 8.61 - 8.51 (m, 3H), 8.23 - 8.20 (m, 3H), 8.12 - 8.11 (d, 1H), 7.92 - 7.67 (m, 3H).

[0114] Triethylamine (24.2 mmol), 2-(2'-pyridyl)benzimidazole (24.2 mmol) and a solution of MeOH (20 mL) were mixed in a 100 mL three-necked flask. The whole system was evacuated and purged with nitrogen, and then stirred at room temperature for 30 minutes. A mixed solution of Ga(NO 3 ) 3 .xH 2 O (12.1 mmol) and MeOH (5 mL) was added. The system was refluxed (70 °C) for 2 h under an inert atmosphere. Then 2-(2'-isoquinolyl)benzimidazole (12.1 mmol) was added and the reaction was refluxed overnight. After the reaction was completed, the mixture was cooled to room temperature (25 °C), and then extracted with dichloromethane. The combined organic layers were washed with brine and dried over MgSO 4 and then the solvent was removed by a rotary evaporator. The crude product was purified by silica gel column chromatography, and the eluents were successively ethyl acetate:dichloromethane = 1:1 (v:v), methanol:dichloromethane = 1:30 (v:v), to obtain a white solid G3 (yield: 27%). 1 H NMR (500 MHz, Chloroform-d) δ 8.78 (d, J = 6.3 Hz, 2H), 8.65 (s, 1H), 7.95 (dd, J = 21.3, 7.5 Hz, 3H), 7.87 (d, J = 7.6 Hz, 1H), 7.82 (d, J = 7.4 Hz, 1H), 7.71 (t, J = 6.7 Hz, 2H), 7.65 (t, J = 6.8 Hz, 1H), 7.61–7.53 (m, 7H), 7.36 (t, J = 8.3 Hz, 2H), 7.26–7.18 (m, 6H).

[0115] Synthesis Example 3: Synthesis of Compound G5

[0116]

[0117] A cold solution of 2-pyridinecarboxaldehyde (3.181 mmol) dissolved in 5 mL of ethanol was added to a cold solution of a mixture of 40 wt% aqueous glyoxal solution (0.2 mL) and 5 mL of ethanol to obtain a reaction mixture. Immediately, a cold concentrated NH 4 OH aqueous solution (0.15 mL, the concentration of NH 4 OH was 25 wt%) was added to the reaction mixture, and it was stirred at 0 °C for 1 hour. Then it was heated to room temperature and stirred for another 5 hours. After the reaction was completed, the solvent was removed under reduced pressure, and the resulting solution was extracted with ether several times. The combined organic extracts were evaporated under reduced pressure, and the crystalline solid was recrystallized with ether to finally obtain brown solid 2-(2'-pyridyl)imidazole (yield: 60%). 1 1H NMR (500 MHz, Chloroform-d) δ 9.5 (s, 1H), 8.73 (dd, J = 4.9, 1.2 Hz, 1H), 7.86 (dd, J = 8.0, 1.1 Hz, 1H), 7.70 (td, J = 8.1, 1.3 Hz, 1H), 7.33–7.25 (m, 3H).

[0118] Triethylamine (24.2 mmol), 2-(2'-pyridyl)benzimidazole (24.2 mmol) and a solution of MeOH (20 mL) were mixed in a 100 mL three-necked flask. The whole system was evacuated and purged with nitrogen, and then stirred at room temperature for 30 minutes. A mixed solution of Ga(NO 3 ) 3 .xH 2 O (12.1 mmol) and MeOH (5 mL) was added, and the system was refluxed (70 °C) for 2 h under an inert atmosphere. Then 2-(2'-pyridyl)imidazole (12.1 mmol) was added and the reflux reaction was carried out overnight. After the reaction was completed, the mixture was cooled to room temperature (25 °C), and then extracted with dichloromethane. The combined organic layers were washed with brine and dried over MgSO 4 , and then the solvent was removed by a rotary evaporator. The crude product was purified by silica gel column chromatography, and the eluent was: methanol:dichloromethane = 1:20 (v:v), and then recrystallized with methanol and dichloromethane to obtain white solid G5 (yield: 25%). 11H NMR (500 MHz, Chloroform-d) δ 8.78 (dd, J = 7.4, 1.5 Hz, 3H), 7.97 (dd, J = 7.5, 1.5 Hz, 3H), 7.71 (td, J = 7.5, 1.6 Hz, 3H), 7.56 (dd, J = 6.8, 2.2 Hz, 4H), 7.36 (td, J = 7.5, 1.7 Hz, 3H), 7.28–7.16 (m, 5H), 7.10 (d, J = 7.5 Hz, 1H).

[0119] Synthesis Example 4: Synthesis of Compound G7

[0120]

[0121] Weigh phenanthraquinone (24.2 mmol), pyridine-2-carboxaldehyde (24.2 mmol) and ammonium acetate (24.2 mmol) into a three-necked flask, introduce nitrogen, add 20 mL of acetic acid, heat under reflux and stir for 5 hours. After the reaction is completed, cool the mixture to room temperature (25 °C), then pour it into a large amount of ice water to produce a large amount of precipitate. Adjust the pH to 7 with dilute NaOH solution, filter the solid, wash the solid thoroughly with water, and then recrystallize with dichloromethane several times to obtain 2-(2'-pyridyl)-phenanthroimidazole as a pale yellow solid powder (yield: 75%). 1 1H NMR (500 MHz, Chloroform-d) δ 9.62 (s, 1H), 8.80 (td, J = 6.7, 1.6 Hz, 3H), 8.28 (dd, J = 7.0, 2.0 Hz, 2H), 8.10–8.05 (m, 1H), 7.76 (td, J = 8.1, 1.3 Hz, 1H), 7.67 (pd, J = 7.4, 1.8 Hz, 4H), 7.34–7.26 (m, 1H).

[0122] Mix triethylamine (24.2 mmol), 2-(2'-pyridyl)benzimidazole (24.2 mmol) and a solution of MeOH (20 mL) in a 100 mL three-necked flask. Evacuate the entire system and purge with nitrogen, then stir at room temperature for 30 minutes. Add a mixed solution of Ga(NO 3 ) 3 .xH 2 O (12.1 mmol) and MeOH (5 mL), reflux the system under an inert atmosphere (70 °C) for 2 h. Then add 2-(2'-pyridyl)-phenanthroimidazole (12.1 mmol) and reflux the reaction overnight. After the reaction is completed, cool the mixture to room temperature (25 °C), and then extract with dichloromethane. The combined organic layers are washed with brine and then with MgSO 4Dry, and then remove the solvent by rotary evaporator. The crude product was purified by silica gel column chromatography, and the eluents were successively: ethyl acetate:dichloromethane = 1:2 (v:v), methanol:dichloromethane = 1:40 (v:v), and then recrystallized from ethanol and dichloromethane several times to obtain white solid G7 (yield: 16%). 1 H NMR (500 MHz, Chloroform-d) δ 8.98 (dd, J = 7.4, 1.5 Hz, 2H), 8.78 (dd, J = 7.4, 1.5 Hz, 3H), 8.11 (dd, J = 7.3, 1.6 Hz, 2H), 7.97 (dd, J = 7.5, 1.5 Hz, 3H), 7.70 (dtd, J = 14.8, 7.5, 1.6 Hz, 5H), 7.62 (td, J = 7.4, 1.6 Hz, 2H), 7.56 (dd, J = 6.8, 2.2 Hz, 4H), 7.36 (td, J = 7.5, 1.7 Hz, 3H), 7.27–7.18 (m, 4H).

[0123] Synthesis Example 5: Synthesis of Compound G9

[0124]

[0125] Stir a mixture of isoquinoline-3-carboxylic acid (0.50 g, 2.9 mmol), o-phenylenediamine (2.9 mmol) and polyphosphoric acid (17.5 g) at 180 °C for 4 h. Cool the mixture to room temperature, then pour it into a large amount of ice water, adjust the pH to 8.0 with 30 wt% NH 4 OH solution, and filter to collect the solid. Wash the solid with water and dry. Treat the solid with boiling toluene to obtain an extract, and evaporate the extract to obtain the white solid product 3-(benzimidazol-2-yl)isoquinoline (yield: 45%). 1 H NMR (400 MHz, DMSO-D6): 13.28 (bs, 1H); 9.50 (s, 1H); 8.84 (s, 1H); 8.24 (d, 1H); 8.19 (d, 1H); 7.87 (t, 1H); 7.77 (t, 1H); 7.71 - 7.52 (m, 2H); 7.25 - 7.22 (m, 2H).

[0126] Mix triethylamine (24.2 mmol), 2-(2'-pyridyl)benzimidazole (24.2 mmol) and MeOH (20 mL) solution in a 100 mL three-necked flask. Evacuate the whole system and purge with nitrogen, then stir at room temperature for 30 min. Add Ga(NO 3 ) 3 .xH 2A mixed solution of O (12.1 mmol) and MeOH (5 mL) was refluxed (70 °C) for 2 h under an inert atmosphere. Then 3-(benzimidazol-2-yl)isoquinoline (12.1 mmol) was added and the reaction was refluxed overnight. After the reaction was completed, the mixture was cooled to room temperature (25 °C), and then extracted with dichloromethane. The combined organic layers were washed with brine and dried over MgSO 4 and then the solvent was removed by a rotary evaporator. The crude product was purified by silica gel column chromatography, and the eluents were successively ethyl acetate:dichloromethane = 1:1 (v:v), methanol:dichloromethane = 1:30 (v:v), to obtain white solid G9 (yield: 25%). 1 H NMR (500 MHz, Chloroform-d) δ 9.34 (d, J = 1.3 Hz, 1H), 8.78 (dd, J = 7.4, 1.5 Hz, 2H), 7.98 (ddd, J = 7.6, 5.3, 1.7 Hz, 3H), 7.86–7.79 (m, 2H), 7.71 (td, J = 7.5, 1.6 Hz, 2H), 7.64 (ddd, J = 6.9, 4.9, 1.8 Hz, 2H), 7.56 (dd, J = 6.8, 2.2 Hz, 6H), 7.36 (td, J = 7.5, 1.6 Hz, 2H), 7.27–7.17 (m, 6H).

[0127] Synthesis Example 6: Synthesis of Compound G11

[0128]

[0129] A mixture of isoquinoline-3-carboxylic acid (0.50 g, 2.9 mmol), o-phenylenediamine (2.9 mmol) and polyphosphoric acid (17.5 g) was stirred at 180 °C for 4 h. The mixture was cooled to room temperature and then poured into a large amount of ice water. The pH was adjusted to 8.0 with 30 wt% NH 4 OH solution, and the solid was collected by filtration. The solid was washed with water and dried. The solid was treated with boiling toluene to obtain an extract, and the extract was evaporated to obtain white solid 2-(benzimidazol-2-yl)quinoline (yield: 57%). 1 H NMR (400 MHz, CDCl 3 ): δ (ppm); 10.96 (s, 1H), 8.59 (d, 1H, 8.5 Hz), 8.34 (d, 1H, 8.7 Hz), 8.14 (d, 1H, 8.7 Hz), 7.91 (m, 1H), 7.90 (d, 1H, 8.7 Hz) 7.78 (ddd, 1H, 8.5, 6.8, 1.5 Hz), 7.60 (ddd, 1H, 8.1, 6.8, 1.2 Hz), 7.50 (m, 1H), 7.33 (m, 2H).

[0130] Triethylamine (24.2 mmol), 2-(2'-pyridyl)benzimidazole (24.2 mmol), and a solution of MeOH (20 mL) were mixed in a 100 mL three-necked flask. The entire system was evacuated and purged with nitrogen, and then stirred at room temperature for 30 minutes. A mixed solution of Ga(NO 3 ) 3 .xH 2 O (12.1 mmol) and MeOH (5 mL) was added. The system was refluxed (70 °C) for 2 h under an inert atmosphere. Then 2-(benzimidazol-2-yl)quinoline (12.1 mmol) was added and the reaction was refluxed overnight. After the reaction was completed, the mixture was cooled to room temperature (25 °C), and then extracted with dichloromethane. The combined organic layers were washed with brine and dried over MgSO 4 , and then the solvent was removed by a rotary evaporator. The crude product was purified by silica gel column chromatography, and the eluents were successively: ethyl acetate:dichloromethane = 1:1 (v:v), methanol:dichloromethane = 1:30 (v:v), to obtain a white solid G11 (yield: 15%). 1 H NMR (500 MHz, Chloroform-d) δ 8.78 (dd, J = 7.4, 1.5 Hz, 2H), 8.43 (dd, J = 7.4, 1.4 Hz, 1H), 8.24 (dd, J = 7.5, 1.5 Hz, 1H), 7.97 (dd, J = 7.5, 1.5 Hz, 2H), 7.80 (ddd, J = 7.3, 4.2, 2.6 Hz, 2H), 7.72 (tdd, J = 7.3, 5.1, 1.6 Hz, 3H), 7.55 (td, J = 6.6, 1.8 Hz, 7H), 7.36 (td, J = 7.5, 1.6 Hz, 2H), 7.26–7.18 (m, 6H).

[0131] Synthesis Example 7: Synthesis of Compound G14

[0132]

[0133] 2,2-Dimethoxyethylamine (2.0 equiv) was weighed into a three-necked flask. Under argon, 30 mL of a THF solution was added, and the temperature was lowered to -78 °C; a hexane solution of nBuLi (n-butyllithium, 2.5 M, 2.0 equiv) was added to the above THF solution of 2,2-dimethoxyethylamine at -78 °C. After stirring for 30 minutes, isoquinoline-1-carbonitrile (1.0 equiv) was added, and the mixture was stirred at 0 °C for 2 h. The reaction was quenched with 20 mL of a 5 vol% MeOH solution in water, the volatiles were removed, and then 6 M HCl solution was added to adjust the pH = 1 to obtain an acidified solution. The acidified solution was refluxed for 18 h, then cooled to room temperature and poured into ice 10 wt% Na2 CO 3 In a solution, it was then extracted with 50 mL of EtOAc (ethyl acetate) and concentrated to obtain the white solid 1-(imidazol-2-yl)isoquinoline. 1 1H-NMR (500 MHz, DMSO-d6): δ 12.93 (bs, 1H), 9.92 (d, 1H, J = 8.0 Hz), 8.51 (d, 2H, J = 5.5 Hz), 7.96 (d, 1H, J = 8.00 Hz), 7.79 (d, 1H, J = 5.0 Hz).

[0134] Triethylamine (24.2 mmol), 2-(2'-pyridyl)benzimidazole (24.2 mmol) and a solution of MeOH (20 mL) were mixed in a 100 mL three-necked flask. The whole system was evacuated and purged with nitrogen, and then stirred at room temperature for 30 minutes. A mixed solution of Ga(NO 3 ) 3 .xH 2 O (12.1 mmol) and MeOH (5 mL) was added, and the system was refluxed (70 °C) for 2 h under an inert atmosphere. Then 1-(imidazol-2-yl)isoquinoline (12.1 mmol) was added and the reaction was refluxed overnight. After the reaction was completed, the mixture was cooled to room temperature (25 °C), and then extracted with dichloromethane. The combined organic layers were washed with brine and dried over MgSO 4 and then the solvent was removed by a rotary evaporator. The crude product was purified by silica gel column chromatography, and the eluents were successively: ethyl acetate:dichloromethane = 1:1 (v:v), methanol:dichloromethane = 1:30 (v:v), to obtain the white solid G3 (yield: 25%). 1 1H NMR (500 MHz, Chloroform-d) δ 8.78 (dd, J = 7.4, 1.5 Hz, 2H), 8.64 (d, J = 7.5 Hz, 1H), 7.95 (ddd, J = 20.0, 7.5, 1.6 Hz, 3H), 7.87 (dd, J = 7.5, 1.5 Hz, 1H), 7.82 (dt, J = 7.4, 1.6 Hz, 1H), 7.71 (td, J = 7.5, 1.6 Hz, 2H), 7.65 (td, J = 7.5, 1.6 Hz, 1H), 7.58 (ddd, J = 18.0, 7.1, 1.9 Hz, 5H), 7.36 (td, J = 7.5, 1.7 Hz, 2H), 7.26–7.16 (m, 5H), 7.10 (d, J = 7.5 Hz, 1H).

[0135] Synthesis Example 8: Synthesis of Compound G16

[0136]

[0137] Add isoquinoline-3-carbonitrile (10 mmol), MeOH (10 mL), and a MeOH solution (30 vol%, volume fraction of NaOMe) of NaOMe (1 mmol) to a 100 mL flask, stir at room temperature for 4 h to obtain a reaction mixture. Add the reactant 2,2-dimethoxyethylamine (11 mmol) to the reaction mixture, then add AcOH (1.2 mL, 20 mmol), and then heat to 50 °C and react for 1 h, and then cool to room temperature. Add MeOH (20 mL) and 6 M HCl solution (5 mL), and heat under reflux for 5 h. After the reaction is completed, take out the solution on the rotary evaporator. Put the residue into a mixture of H 2 O and Et 2 O (30 mL) in a volume ratio of 1:1 to separate the layers. Adjust the pH of the aqueous layer to pH 8-9 with 2 M aqueous NaOH solution, and stir for 30 minutes to completely precipitate the product. Filter and collect the solid, dry the mixture under vacuum, and purify the crude product by silica gel column chromatography. The eluent is: chloroform:methanol:concentrated ammonia = 500:10:1 (v:v:v) to obtain 3-(imidazol-2-yl)isoquinoline (yield: 55%). 1 H NMR (300 MHz, CDCl3) δ 11.13 (br s, 1H), 9.17 (s, 1H), 8.57 (s, 1H), 7.95 (d, 1H, J = 8.3 Hz), 7.89 (d, 1H, J = 8.2 Hz), 7.69 (dt, 1H, J = 7.0, 1.2 Hz), 7.58 (dt, 1H, J = 7.0, 1.1 Hz), 7.28 (br s, 1H), 7.17 (br s, 1H).

[0138] Mix triethylamine (24.2 mmol), 2-(2'-pyridyl)benzimidazole (24.2 mmol), and a MeOH (20 mL) solution in a 100 mL three-necked flask. Evacuate the whole system and purge with nitrogen, and then stir at room temperature for 30 minutes. Add a mixed solution of Ga(NO 3 ) 3 .xH 2 O (12.1 mmol) and MeOH (5 mL), and reflux the system under an inert atmosphere (70 °C) for 2 h. Then add 2-(2'-pyridyl)imidazole (12.1 mmol) and reflux for reaction overnight. After the reaction is completed, cool the mixture to room temperature (25 °C), and then extract with dichloromethane. The combined organic layers are washed with brine and then with MgSO 4Dry and then remove the solvent by rotary evaporator. The crude product was purified by silica gel column chromatography, and the eluents were successively: ethyl acetate:dichloromethane = 1:1 (v:v), methanol:dichloromethane = 1:30 (v:v), to obtain white solid G16 (yield: 25%). 1 H NMR (500 MHz, Chloroform-d) δ 9.34 (d, J = 1.4 Hz, 1H), 8.78 (dd, J = 7.4, 1.5 Hz, 2H), 7.98 (ddd, J = 7.6, 5.5, 1.7 Hz, 3H), 7.89–7.79 (m, 2H), 7.71 (td, J = 7.5, 1.6 Hz, 2H), 7.64 (tt, J = 7.4, 5.6 Hz, 2H), 7.56 (dd, J = 6.8, 2.2 Hz, 4H), 7.36 (td, J = 7.5, 1.7 Hz, 2H), 7.27–7.17 (m, 5H), 7.10 (d, J = 7.5 Hz, 1H).

[0139] Synthesis Example 9: Synthesis of Compound G18

[0140]

[0141] A cold solution of 2-quinolinecarboxaldehyde (3.181 mmol) and 5 mL of ethanol was added to a cold solution of 40 wt% aqueous glyoxal solution (0.2 mL) and 5 mL of ethanol to obtain a reaction mixture. Immediately, cold concentrated NH 4 OH aqueous solution (0.15 mL, the concentration of NH 4 OH is 25 wt%) was added to the reaction mixture, and the mixture was stirred at 0 °C for 1 hour. Then it was heated to room temperature and stirred for another 5 hours. After the reaction was completed, the solvent was removed under reduced pressure, and the resulting solution was extracted with ether several times. The combined organic extracts were evaporated under reduced pressure, and the crystalline solid was recrystallized with ether to obtain the brown solid product 2-(imidazol-2-yl)quinoline (yield: 45%). 1 H NMR (400 MHz, Chloroform-d): δ 11.13 (s, 1H) 8.35 (d, 1H, 8.6 Hz), 8.25 (d, 1H, 8.6 Hz), 8.02 (d, 1H, 8.6 Hz), 7.84 (d, 1H, 8.4 Hz), 7.70 (td, 1H, 7.6, 1.1 Hz), 7.53 (td, 1H, 7.6, 1.1 Hz), 7.31 (s, 1H), 7.19 (s, 1H).

[0142] Triethylamine (24.2 mmol), 2-(2'-pyridyl)benzimidazole (24.2 mmol) and a solution of MeOH (20 mL) were mixed in a 100 mL three-necked flask. The whole system was evacuated and purged with nitrogen, and then stirred at room temperature for 30 minutes. A mixed solution of Ga(NO 3 ) 3 .xH 2 O (12.1 mmol) and MeOH (5 mL) was added, and the system was refluxed (70 °C) for 2 h under an inert atmosphere. Then 2-(imidazol-2-yl)quinoline (12.1 mmol) was added and the reaction was refluxed overnight. After the reaction was completed, the mixture was cooled to room temperature (25 °C), and then extracted with dichloromethane. The combined organic layers were washed with brine and dried over MgSO 4 , and then the solvent was removed by a rotary evaporator. The crude product was purified by silica gel column chromatography, and the eluents were successively: ethyl acetate:dichloromethane = 1:1 (v:v), methanol:dichloromethane = 1:30 (v:v), to obtain a white solid G18 (yield: 30%). 1 H NMR (500 MHz, Chloroform-d) δ 8.78 (dd, J = 7.4, 1.5 Hz, 2H), 8.43 (dd, J = 7.4, 1.4 Hz, 1H), 8.24 (dd, J = 7.5, 1.5 Hz, 1H), 7.97 (dd, J = 7.4, 1.5 Hz, 2H), 7.80 (ddd, J = 7.3, 4.2, 2.6 Hz, 2H), 7.72 (tdd, J = 7.3, 5.1, 1.6 Hz, 3H), 7.55 (td, J = 6.7, 1.8 Hz, 5H), 7.36 (td, J = 7.5, 1.7 Hz, 2H), 7.26–7.16 (m, 5H), 7.10 (d, J = 7.5 Hz, 1H).

[0143] Synthesis Example 10: Synthesis of Compound G19

[0144]

[0145] Pyridine-2-boronic acid (2.2 mmol), 2-bromo-4-hydroxypyridine (2.0 mmol), K 2 CO 3 (4.0 mmol) and Pd(PPh 3 ) 4 (0.02 mmol) were weighed into a three-necked flask. The whole system was evacuated and purged with nitrogen, and then 30 mL of toluene, 5 mL of ethanol and 5 mL of water were added, and the mixture was refluxed at 90 °C for 12 h. After the reaction was completed, it was cooled to room temperature. The mixture was extracted with ethyl acetate (3 × 40 mL), washed with water 3 times, and dried over MgSO 4The combined extracts were dried and evaporated to dryness. The crude product was purified by silica gel column chromatography, and the eluents were successively: petroleum ether:dichloromethane = 2:1 (v:v), to obtain the white solid product [2,2'-bipyridine]-4-one (yield: 25%). 1 H NMR (500 MHz, Chloroform-d) δ 9.15 (s, 1H), 8.59 (dd, J = 5.0, 1.3 Hz, 1H), 8.20 (d, J = 10.8 Hz, 1H), 7.74 (dd, J = 7.9, 1.0 Hz, 1H), 7.54 (td, J = 8.0, 1.3 Hz, 1H), 7.43 (ddd, J = 7.9, 4.9, 0.9 Hz, 1H), 6.09–5.99 (m, 2H).

[0146] Triethylamine (24.2 mmol), 2-(2'-pyridyl)benzimidazole (24.2 mmol) and a solution of MeOH (20 mL) were mixed in a 100 mL three-necked flask. The whole system was evacuated and purged with nitrogen, and then stirred at room temperature for 30 minutes. A mixed solution of Ga(NO 3 ) 3 .xH 2 O (12.1 mmol) and MeOH (5 mL) was added, and the system was refluxed (70 °C) for 2 h under an inert atmosphere. Then [2,2'-bipyridine]-4-one (12.1 mmol) was added and the reaction was refluxed overnight. After the reaction was completed, the mixture was cooled to room temperature (25 °C), and then extracted with dichloromethane. The combined organic layers were washed with brine and dried over MgSO 4 and then the solvent was removed by a rotary evaporator. The crude product was purified by silica gel column chromatography, and the eluent was: methanol:dichloromethane = 1:30 (v:v), and then recrystallized from methanol and dichloromethane to obtain the white solid G19 (yield: 20%). 1 H NMR (500 MHz, Chloroform-d) δ 8.78 (dd, J = 7.4, 1.5 Hz, 2H), 8.63 (dd, J = 7.5, 1.4 Hz, 1H), 7.97 (dd, J = 7.4, 1.5 Hz, 2H), 7.71 (td, J = 7.5, 1.6 Hz, 2H), 7.56 (dd, J = 6.8, 2.2 Hz, 4H), 7.49 (dd, J = 7.5, 1.6 Hz, 1H), 7.44 (td, J = 7.5, 1.5 Hz, 1H), 7.36 (td, J = 7.5, 1.7 Hz, 2H), 7.27–7.12 (m, 6H), 6.99 (d, J = 11.0 Hz, 1H), 6.65 (s, 1H).

[0147] Other compounds of the present application can all be synthesized by selecting appropriate raw materials according to the idea of the above synthesis examples, or any other appropriate methods and raw materials can also be selected for synthesis.

[0148] Example 1

[0149] A 15 Ω / cm (1200 A) ITO glass substrate manufactured by Corning was cut into a size of 50 mm × 50 mm × 0.7 mm, then ultrasonically treated with isopropyl alcohol and pure water for 5 minutes respectively, irradiated with ultraviolet (UV) light for 30 minutes, and exposed to ozone for cleaning, and then loaded onto a vacuum deposition device as the ITO anode.

[0150] NPB was vacuum deposited on the ITO anode to form a hole injection layer with a thickness, and then TCTA was vacuum deposited on the hole injection layer to form a hole transport layer with a thickness. The compound G1 (1 wt%) as a dopant (guest material) and BCPO as a host material were co-deposited on the hole transport layer to form a light-emitting layer with a thickness.

[0151] TSPO1 was vacuum deposited on the light-emitting layer to form a hole blocking layer with a thickness. Then, TPBi was deposited on the hole blocking layer to form an electron transport layer with a thickness. LiF (which is an alkali metal halide) was deposited on the electron transport layer to form an electron injection layer with a thickness, and Al was vacuum deposited on the electron injection layer to form a LiF / Al electrode (cathode) with a thickness, thus forming an organic electroluminescent device.

[0152]

[0153] Examples 2 - 10

[0154] Except that the guest materials of the light-emitting layer were replaced by G3, G5, G7, G9, G11, G14, G16, G18, G19 instead of G1 respectively, the rest were the same as in Example 1. See Table 1 for details.

[0155] Comparative Example 1

[0156] Except that the guest material of the light-emitting layer was selected as fac-PhP, the rest were the same as in Example 1; the structure of fac-PhP is as follows:

[0157]

[0158] The following performance measurements were carried out on the organic electroluminescent devices prepared by the above process:

[0159] Under the same brightness, the driving voltage, current efficiency and device lifetime of the organic electroluminescent devices prepared in Examples 1-10 and Comparative Example 1 were measured using a digital source meter and a luminance meter. Specifically, the voltage was increased at a rate of 0.1 V per second, and the voltage when the brightness of the organic electroluminescent device reached 700 cd / m 2 was measured as the driving voltage, and the current density at this time was also measured; the ratio of brightness to current density was the current efficiency; the LT95 lifetime test was as follows: using a luminance meter at 700 cd / m 2 brightness, keeping a constant current, and measuring the time when the brightness of the organic electroluminescent device dropped to 650 cd / m 2 , with the unit of hours. The results are shown in Table 1.

[0160] Table 1 Performance Results of Organic Electroluminescent Devices

[0161]

[0162] As can be seen from Table 1, when the compounds G1, G3, G5, G7, G9, G11, G14, G16, G18, and G19 prepared in this application are used as the host materials of the light-emitting layer in organic electroluminescent devices, compared with Comparative Example 1, the driving voltage of the organic electroluminescent device is significantly lower, the current efficiency is significantly higher, and the LT95 lifetime is significantly longer. The results show that the compounds provided in this application as the host materials of the light-emitting layer in organic electroluminescent devices can effectively reduce the driving voltage, improve the current efficiency, and extend the service life of the device, and are blue-light host materials with good performance.

[0163] The above are only the preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of this application shall be included within the scope of protection of this application.

Claims

1. A compound of formula (I): Wherein, R 1 and R 2 each independently selected from hydrogen, deuterium, halogen, C 1- C 10 alkyl, C 3- C 10 cycloalkyl, C 6- C 14 aryl, C 2- C 14 heteroaryl, C 1- C 10 alkoxy, amine group which is unsubstituted or substituted by Ra, and each Ra is independently selected from fluorine, deuterium, methyl or tert-butyl; the heteroatoms on the heteroaryl are each independently selected from N, O, S; Ring A is selected from an N-containing five-membered ring group or an N-containing six-membered ring group; Y 1 is selected from =O, p is selected from 0 or 1; Y 2 is selected from C 1- C 10 alkyl, q is selected from 0 or 1; Ring B is selected from absent or C 6- C 18 aryl; Y 3 selected from C 1- C 10 alkyl, and r is selected from 0 or 1; X 1 , X 2 , X 3 , X 4 are each independently selected from hydrogen, C 1- C 10 Hydrocarbon, X 1 , X 2 , X 3 , X 4 The two adjacent groups in the 1- C 3 an alkyl-substituted six-membered ring; n is selected from 1, 2 or 3.

2. The compound according to claim 1, Wherein, R 1 、R 2 each independently selected from hydrogen, halogen, unsubstituted or fluorine-substituted C 1- C 6 alkyl groups.

3. The compound according to claim 1, Wherein, The ring A is selected from Preferably, the ring B is selected from absent, 4. The compound according to claim 1, Wherein, Structural unit Selected from 5. The compound according to claim 1, Wherein, Structural unit Selected from 6. The compound according to claim 1, Wherein, The compound is a compound of formula (IIa), formula (IIb), formula (IIc) or formula (IId):

7. The compound according to claim 1, Wherein, The compound is selected from the following compounds:

8. An organic light-emitting material comprising at least one of the compounds according to any one of claims 1-7.

9. An organic electroluminescent device comprising at least one of the organic light-emitting materials according to claim 8; preferably, the organic light-emitting material is used as a blue light host material.

10. A display device comprising the organic electroluminescent device according to claim 9.

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