A pyrazine derivative and its application in OLED devices

Abstract

The invention discloses a pyrazine derivative and application thereof in an OLED device, belonging to the technical field of organic synthesis, and the general structural formula is shown in formula (I); the compound with 2-methyldiindeno[1,2-b:1',2'-e]pyrazine-6,12-dione as the core provided by the invention has good charge transfer capability, suitable HOMO / LUMO value and good thermal stability, can be used in an organic electroluminescent device to achieve high brightness, low voltage, high efficiency and long service life, and can be widely used in OLED light-emitting devices and display devices as a main material of a blue light-emitting layer or a thermally active delayed fluorescent light-emitting material;

Description

Technical Field

[0001] The invention belongs to the technical field of organic synthesis, and particularly relates to a pyrazine derivative and application thereof in an OLED device. Background Art

[0002] As a self-luminous electronic component, the luminescence mechanism of organic light-emitting diodes (OLED) display and lighting components is a new optoelectronic information technology that directly converts electrical energy into light energy with the help of organic semiconductor functional materials under the action of a DC electric field. Its luminous color can be red, green, blue, yellow light alone or a combination of white light. The biggest feature of OLED luminous display technology is that it is ultra-thin, fast response speed, ultra-lightweight, surface luminous and flexible display. It can be used to manufacture monochrome or full-color displays. As a new light source technology, it can also be used to make lighting and display products or new backlight technology for manufacturing liquid crystal displays.

[0003] According to the principle of light emission, organic electroluminescent elements (organic EL elements) can be divided into two categories: fluorescent type and phosphorescent type. When voltage is applied to the organic electroluminescent element, holes from the anode and electrons from the cathode are injected, and they are combined again in the light-emitting layer to form excitons. According to the electron spin statistics method, singlet excitons and triplet excitons are generated in a ratio of 25%:75%. Because the fluorescent type uses singlet excitons to emit light, its internal quantum efficiency can only reach 25%. Phosphorescent materials are composed of heavy metal elements, and singlet and triplet energy can be used simultaneously through interstitial crossing, and the internal quantum efficiency can reach 100%. Thermally activated delayed fluorescence (TADF) materials are the third generation of organic light-emitting materials developed after organic fluorescent materials and organic phosphorescent materials. This type of material generally has a small singlet-triplet energy level difference (ΔEst). Triplet excitons can be transformed into singlet excitons through anti-gap crossing to emit light. The singlet excitons and triplet excitons formed under electrical excitation can be fully utilized. The internal quantum efficiency of the device can reach 100%. At the same time, the material structure is controllable, the properties are stable, the price is cheap, and no precious metals such as iridium and platinum are required. It has broad application prospects in the field of OLEDs. Research results in recent years have shown that green and red phosphorescent materials can meet industrialization requirements, but there is still a problem of high prices, and the life of blue phosphorescent materials cannot meet application requirements and therefore cannot be industrialized. At present, the blue light materials in OLED products are still traditional fluorescent materials. Traditional blue light fluorescent materials are mostly based on anthracene and pyrene as the core skeleton. This type of material has low efficiency and unsatisfactory life. Therefore, it is urgent to develop a new type of high-performance blue light material with a new skeleton.

[0004] TADF materials can be used not only as the luminescent material (emitter) in the luminescent layer, but also as the main material or auxiliary main material in the luminescent layer to sensitize the emitter. This type of device helps to improve the efficiency of traditional devices, improve the color purity of the device, and increase the working life of the device. It is a type of organic electroluminescent functional material with broad application prospects. The structure of TADF materials is generally composed of electron-donating groups and electron-withdrawing groups connected by π bonds. However, there are currently few types of electron-withdrawing groups that can be used, especially high-quality TADF blue-light materials. In addition, the color purity of the blue-light materials currently reported is defective, and the device life is not ideal and cannot meet the requirements of practical application. Therefore, it is very important to develop new blue-light TADF materials. Summary of the invention

[0005] In order to solve the above problems, the present invention discloses a pyrazine derivative and application thereof in an OLED device.

[0006] The first object of the present invention is to provide a pyrazine derivative, the general structural formula of which is shown in formula (I):

[0007]

[0008] Wherein, Ar1 and Ar2 are independently selected from donor groups or condensed ring aromatic groups;

[0009] The donor group is a group represented by formula (II), formula (III), formula (IV), formula (V), formula (VI), formula (VII), formula (VIII), formula (IX) or formula (X):

[0010]

[0011] In formula (II), Ar3 and Ar4 are independently selected from substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl;

[0012] In formula (III), R1 and R2 are independently selected from a hydrogen atom or a C1-C6 alkyl group;

[0013] In formula (IV), X3 is C-m1m2, O or S, and m1 and m2 are independently selected from substituted or unsubstituted aryl or C1-C6 alkyl;

[0014] In formula (V) and formula (VI), Y is C or Si;

[0015] Formula (IX) is a C18-C24 fused heterocyclic group containing two five-membered rings;

[0016] In formula (X), Z is C-m3m4, N-m5, O or S, m3 and m4 are independently selected from C1 to C6 alkyl, and m5 is substituted or unsubstituted aryl;

[0017] The condensed ring aromatic group is a group represented by formula (B1), formula (B2), formula (B3), formula (B4) or formula (B5):

[0018]

[0019] Preferably, in the formula (II), Ar3 and Ar4 are independently selected from substituted or unsubstituted phenyl, substituted or unsubstituted dibenzofuranyl, substituted or unsubstituted fluorenyl; when it is substituted phenyl, these substituents are C1~C6 alkyl, phenyl, halogen, -CF3 or -CN; when it is substituted dibenzofuranyl, these substituents are C1~C6 alkyl, when it is substituted fluorenyl, these substituents are C1~C6 alkyl.

[0020] Preferably, in the formula (II), Ar3 and Ar4 are independently selected from phenyl, methylphenyl, isopropylphenyl, biphenyl, trifluoromethylphenyl, fluorophenyl, cyanophenyl, dibenzofuranyl, isopropyldibenzofuranyl, fluorenyl or dimethylfluorenyl.

[0021] Preferably, in the formula (III), R1 and R2 are independently selected from a hydrogen atom or a tert-butyl group.

[0022] Preferably, in the formula (IV), m1 and m2 are independently selected from methyl or phenyl.

[0023] Preferably, the formula (IX) is selected from one of the following structural formulas:

[0024]

[0025]

[0026] Preferably, the pyrazine derivatives include the following compounds:

[0027]

[0028]

[0029]

[0030] The second object of the present invention is to provide use of the pyrazine derivatives in organic electroluminescent devices.

[0031] Preferably, the organic electroluminescent device comprises a light-emitting layer, characterized in that the light-emitting layer material comprises the above-mentioned pyrazine derivative.

[0032] The third object of the present invention is to provide application of the organic electroluminescent device in an organic electroluminescent display device.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] The present invention introduces specific donor groups or condensed rings to modify 2-methyldiindeno[1,2-b:1',2'-e]pyrazine-6,12-dione to form a new compound, and by indenone ligands being incorporated on both sides of pyrazine, the triplet energy of pyrazine is improved and the electron transmission capacity of the core skeleton is optimized; by introducing various electron-donating groups for modification, the compound has donor-acceptor bipolar characteristics, the frontier orbital energy level distribution of the material is improved, the energy difference between the singlet and triplet states is reduced, and the compound has TADF properties; by connecting condensed ring molecules such as anthracene and pyrene, the stability and band gap of the material are improved, so that the compound is suitable for use as a blue light host material, and this series of compounds exhibits excellent performance as a blue light host material or a luminescent material in an organic electroluminescent device. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic diagram of the structure of the organic electroluminescent device provided by the present invention;

[0036] Figure 2 is a voltage-efficiency-current density relationship diagram of the device in device embodiment 6;

[0037] Figure 3 is the LT of the device in device embodiment 6 90 Life test curve chart;

[0038] Description of reference numerals:

[0039] 1. Substrate; 2. Anode layer; 3. Hole injection layer; 4. First hole transport layer; 5. Second hole transport layer; 6. Light-emitting layer; 7. Hole blocking layer; 8. Electron transport layer; 9. Electron injection layer; 10. Cathode layer. DETAILED DESCRIPTION

[0040] In order to enable those skilled in the art to better understand and implement the technical solution of the present invention, the present invention is further described below in conjunction with specific embodiments and drawings, but the embodiments are not intended to limit the present invention.

[0041] The experimental methods and detection methods described in the following examples are all conventional methods unless otherwise specified; the reagents and raw materials described are all commercially available unless otherwise specified.

[0042] The present invention provides a pyrazine derivative, the general structural formula of which is shown in formula (I):

[0043]

[0044] Wherein, Ar1 and Ar2 are independently selected from donor groups or condensed ring aromatic groups;

[0045] The donor group is a group represented by formula (II), formula (III), formula (IV), formula (V), formula (VI), formula (VII), formula (VIII), formula (IX) or formula (X):

[0046]

[0047] In formula (II), Ar3 and Ar4 are independently selected from substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl;

[0048] In formula (III), R1 and R2 are independently selected from a hydrogen atom or a C1-C6 alkyl group;

[0049] In formula (IV), X3 is C-m1m2, O or S, and m1 and m2 are independently selected from substituted or unsubstituted aryl or C1-C6 alkyl;

[0050] In formula (V) and formula (VI), Y is C or Si;

[0051] Formula (IX) is a C18-C24 fused heterocyclic group containing two five-membered rings;

[0052] In formula (X), Z is C-m3m4, N-m5, O or S, m3 and m4 are independently selected from C1 to C6 alkyl, and m5 is substituted or unsubstituted aryl;

[0053] The condensed ring aromatic group is a group represented by formula (B1), formula (B2), formula (B3), formula (B4) or formula (B5):

[0054]

[0055] Below, we provide specific synthetic methods for preparing the above compounds and several corresponding intermediates.

[0056] Intermediate 1-1 and intermediate 1-2 are synthesized according to existing methods.

[0057] (1) Synthesis of intermediate 1-3:

[0058]

[0059] In a 1L three-necked flask, add 60g of intermediate 1-1 and 600ml of toluene, heat to 40°C, slowly dropwise add 36.6g of intermediate 1-2 in 80ml of concentrated hydrochloric acid solution, keep stirring at this temperature for 5h, then take samples to monitor the reaction progress, stop stirring after the raw materials are completely reacted, cool to room temperature, extract the reaction solution with dichloromethane, combine the organic phases, adjust to neutral with saturated sodium bicarbonate solution, then wash the organic phase with saturated brine, dry with sodium sulfate, and purify through a silica gel column to obtain 38.8g of intermediate 1-3 with a yield of 56.8%.

[0060] 1 H NMR (400MHz, CDCl3) δ7.58 (d, J = 7.6, 1H), 7.43 (m, 2H), 2.61 (s, 2H), 2.03 (br, 1H);

[0061] (2) Synthesis of intermediate 1-4:

[0062]

[0063] Add 38g of intermediate 1-3, 96.5g of sodium thiosulfate, 400ml of ethanol, and 300ml of ammonia water (25%) to a 1L three-necked flask, heat to 80°C, reflux for 8h, then take samples to monitor the reaction progress. Stop stirring after the raw materials are completely reacted, and cool to room temperature. The reaction system is extracted with dichloromethane, the organic phase is washed with water until neutral, dried with anhydrous sodium sulfate, and purified by silica gel column to obtain 21.4g of intermediate 1-4, with a yield of 32.6%.

[0064] 1 H NMR (400MHz, CDCl3) δ7.30 (m, 4H), 7.25 (d, J = 8.8, 2H), 3.81 (s, 4H);

[0065] (3) Synthesis of intermediate 1:

[0066]

[0067] Add 150ml of water to a 500ml three-necked flask, slowly add 50.7g of sodium dichromate and 43.3ml of concentrated sulfuric acid under stirring, then add 20g of intermediate 1-4, heat to 80℃, stir and react for 6h, then take samples to monitor the reaction progress, stop stirring after the raw materials are completely reacted, and cool to room temperature. Pour the reaction solution into ice water, extract with dichloromethane, adjust the organic phase to neutral with saturated sodium bicarbonate solution, then wash with saturated brine, and dry with anhydrous sodium sulfate. The organic phase is purified by silica gel column and recrystallized with toluene to obtain 5.5g of intermediate 1, with a yield of 25.7%.

[0068] 1 H NMR (400MHz, CDCl3) δ8.04 (s, 2H), 7.77 (d, J = 8.8, 2H), 7.56 (d, J = 8.8, 2H);

[0069] (4) Synthesis of Compound 1:

[0070]

[0071] Add 10g of intermediate 1, 8.3g of compound 1-1, 8.6g of sodium carbonate, 0.91g of 1,10-phenanthroline, and 300ml of toluene to a 500ml three-necked flask, introduce nitrogen for 5min to expel oxygen from the system, and add 0.64g of cuprous bromide. Heat the system to 110℃ and reflux for 6h, then take a sample and monitor the reaction by TLC. When the raw materials react completely, stop heating and cool to room temperature. Filter the reaction solution and wash with water until pH=7. Dry the organic phase with anhydrous sodium sulfate and purify it with a silica gel column to remove insoluble impurities. The crude product obtained by concentrating the eluent is recrystallized from toluene to obtain 11.6g of compound 1, with a yield of 83.6%.

[0072] 1 H NMR (400MHz, CDCl3) δ7.9 (s, 2H), 7.7 (d, J = 8.0, 2H), 7.55-7.60 (m, 6H), 7.40 (d, J = 6.8, 4H), 7.00-7.08 (m, 8H);

[0073] (5) Synthesis of Compound 3:

[0074]

[0075] In a 500ml three-necked flask, add 10g of intermediate 1, 10.4g of compound 3-1, 8.6g of sodium carbonate, 0.91g of 1,10-phenanthroline, and 300ml of toluene. Pass nitrogen for 5min to expel oxygen from the system, and add 0.64g of cuprous bromide. Heat the system to 110℃ and reflux for 6h, then take a sample and monitor the reaction by TLC. When the raw materials react completely, stop heating and cool to room temperature. Filter the reaction solution and wash with water until pH=7. Dry the organic phase with anhydrous sodium sulfate and purify it with a silica gel column to remove insoluble impurities. The crude product obtained by concentrating the eluent is recrystallized from toluene to obtain 10.6g of compound 3, with a yield of 67.2%.

[0076] 1 H NMR (400MHz, CDCl3) δ7.42 (d, J = 8.8, 2H), 7.07 (s, 2H), 6.80-6.88 (m, 10H), 6.54 (t, J = 7.2, 4H), 6.38 (d, J = 7.2, 4H), 1.67 (s, 12H);

[0077] (6) Synthesis of compound 11:

[0078]

[0079] In a 500ml three-necked flask, add 10g of intermediate 1, 14.1g of compound 11-1, 8.6g of sodium carbonate, 0.91g of 1,10-phenanthroline, and 300ml of toluene. Pass nitrogen for 5min to expel oxygen from the system, and add 0.64g of cuprous bromide. Heat the system to 110℃ and reflux for 6h, then take a sample and monitor the reaction by TLC. When the raw material reacts completely, stop heating and cool to room temperature. Filter the reaction solution and wash with water until pH=7. Dry the organic phase with anhydrous sodium sulfate and purify it with a silica gel column to remove insoluble impurities. The crude product obtained by concentrating the eluent is recrystallized from toluene to obtain 14.1g of compound 11, with a yield of 73.8%.

[0080] 1 H NMR (400MHz, CDCl3) δ8.06 (d, J = 6.8, 2H), 7.93 (s, 2H), 7.55-7.70 (m, 10H), 7.24-7.44 (m, 8H), 7.00-7.08 (m, 4H), 1.67 (s, 12H);

[0081] (7) Synthesis of Compound 28:

[0082]

[0083] In a 500ml three-necked flask, add 10g of intermediate 1, 16.7g of compound 28-1, 8.6g of sodium carbonate, 0.91g of 1,10-phenanthroline, and 300ml of toluene. Pass nitrogen for 5min to expel oxygen from the system, and add 0.64g of cuprous bromide. Heat the system to 110℃ and reflux for 6h, then take a sample and monitor the reaction by TLC. When the raw material reacts completely, stop heating and cool to room temperature. Filter the reaction solution and wash with water until pH=7. Dry the organic phase with anhydrous sodium sulfate and purify it with a silica gel column to remove insoluble impurities. The crude product obtained by concentrating the eluent is recrystallized from toluene to obtain 18.7g of compound 28, with a yield of 86.8%.

[0084] 1 H NMR (400MHz, CDCl3) δ7.48(d,J=6.4,6H),7.42(d,J=7.2,4H),7.32(t,J=6.4,4H),7.19-7.24(m,8H),7.13( d,J=6.8,2H),7.07(s,2H),6.85-6.88(m,4H),6.80(d,J=8.8,2H),6.52(d,J=6.4,4H),6.39(d,J=6.8,2H);

[0085] (8) Synthesis of compound 37:

[0086]

[0087] In a 500ml three-necked flask, add 10g of intermediate 1, 14.1g of compound 3-1, 8.6g of sodium carbonate, 0.91g of 1,10-phenanthroline, and 300ml of toluene. Pass nitrogen for 5min to expel oxygen from the system, and add 0.64g of cuprous bromide. Heat the system to 110℃ and reflux for 6h, then take a sample and monitor the reaction by TLC. When the raw materials react completely, stop heating and cool to room temperature. Filter the reaction solution and wash with water until pH=7. Dry the organic phase with anhydrous sodium sulfate and purify it with a silica gel column to remove insoluble impurities. The crude product obtained by concentrating the eluent is recrystallized from toluene to obtain 14.5g of compound 37, with a yield of 75.6%.

[0088] 1 H NMR (400MHz, CDCl3) δ7.49 (d, J = 6.8, 2H), 7.42 (d, J = 8.8, 2H), 7.26-7.29 (m, 4H), 7.19 (t, J = 6.8, 2H), 7. 13(t,J=6.8,2H),7.07(s,2H),6.85-6.88(m,4H),6.80(m,4H),6.64(d,J=6.8,2H),6.39(d,J=6.8,2H);

[0089] (9) Synthesis of Compound 47:

[0090]

[0091] In a 500ml three-necked flask, add 10g of intermediate 1, 11.1g of compound 47-1, 12.5g of potassium carbonate, 0.7g of tetrabutylammonium bromide, 200ml of toluene, 60ml of ethanol, and 40ml of water. Pass nitrogen for 5min to expel oxygen in the system, and add 1.3g of tetrakis(triphenylphosphine)palladium. Heat the system to 80℃ for 6h and then take a sample to monitor the reaction by TLC. When the raw materials react completely, stop heating and cool to room temperature. Filter the reaction solution and wash with water until pH=7. Dry the organic phase with anhydrous sodium sulfate and purify it with a silica gel column to remove insoluble impurities. The crude product obtained by concentrating the eluent is recrystallized from toluene to obtain 10.4g of compound 47, with a yield of 72.2%.

[0092] 1 H NMR (400MHz) δ8.27(s,2H),8.09(s,2H),7.91(d,J=7.2,8H),7.82(d,J=8.0,2H),7.73(d,J=8.8,2H),7.39(t,J=7.2,8H);

[0093] (10) Synthesis of Compound 52:

[0094]

[0095] In a 500ml three-necked flask, add 10g of intermediate 1, 12.4g of compound 52-1, 12.5g of potassium carbonate, 0.7g of tetrabutylammonium bromide, 200ml of toluene, 60ml of ethanol, and 40ml of water. Pass nitrogen for 5min to expel oxygen in the system, and add 1.3g of tetrakis(triphenylphosphine)palladium. Heat the system to 80℃ for 6h and then take a sample to monitor the reaction by TLC. When the raw materials react completely, stop heating and cool to room temperature. Filter the reaction solution and wash with water until pH=7. Dry the organic phase with anhydrous sodium sulfate and purify it with a silica gel column to remove insoluble impurities. The crude product obtained by concentrating the eluent is recrystallized from toluene to obtain 11.8g of compound 52, with a yield of 75.9%.

[0096] 1 H NMR(400MHz)δ8.12(d,J=7.2,2H),8.09(s,2H),8.04(d,J=7.2,2H),7.94(d,J =7.2,2H),7.88(d,J=6.8,2H),7.82(m,4H),7.73(d,J=8.8,2H),7.71(s,8H).

[0097] The T1 energy level and HOMO and LUMO energy level tests were performed on some of the compounds and existing materials provided in the above examples, and the results are shown in Table 1:

[0098] Table 1 T1 energy level and HOMO, LUMO of the compounds of the present invention

[0099]

[0100] Note: The triplet energy (T1) of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) as well as ΔEst are the data obtained by simulation calculation using Gaussian 09 software, using the B3LYP hybrid functional and basis set 6-31g (d, P).

[0101] As can be seen from Table 1, the organic compounds of the present invention have a more suitable HOMO / LUMO, which is beneficial to the transport of carriers and the transfer of energy in OLED devices. These compounds can be used as fluorescent host materials or TADF host materials, and can also be used as TADF luminescent materials. In the absence of specific restrictions, the above-mentioned organic electroluminescent device can be a phosphorescent device or a fluorescent device or a device containing a thermally activated delayed fluorescence (TADF) material. Therefore, the compound of the present invention with 2-methyldiindeno[1,2-b:1',2'-e]pyrazine-6,12-dione as the core can effectively improve the luminous efficiency and service life of the device after being applied to the light-emitting layer of the OLED device.

[0102] Taking some compounds provided by the present invention as examples, they are respectively used as light-emitting layer materials (host materials and / or doped dyes) in organic electroluminescent devices to verify the excellent effects achieved.

[0103] The excellent effect of the OLED material of the present invention in the device is specifically described in detail through the device performance of device embodiments 1 to 7 and comparative example 1. The structure and manufacturing process of the device embodiments 1 to 7 of the present invention and comparative example 1 are exactly the same, and the same glass substrate and electrode material are used, and the film thickness of the electrode material is also consistent. The difference is that the light-emitting layer material has been adjusted, as follows.

[0104] Device Application Examples

[0105] Device Example 1

[0106] This embodiment provides an organic electroluminescent device, the structure of which is as follows: Figure 1 As shown, it includes a substrate 1, an anode layer 2, a hole injection layer 3, a first hole transport layer 4, a second hole transport layer 5, a light emitting layer 6, a hole blocking layer 7, an electron transport layer 8, an electron injection layer 9 and a cathode layer 10 which are stacked in sequence.

[0107] Among them, the material of the anode layer 2 is indium tin oxide (ITO) with a high work function, the material of the hole injection layer 3 is HAT-CN with a thickness of 5nm; the material of the first hole transport layer 4 is NPB with a thickness of 60nm; the material of the second hole transport layer 5 is TCTA with a thickness of 15nm; the light-emitting layer 6 uses compound 47 as the main material and BD01 as the light-emitting material, with a doping mass ratio of 5% and a thickness of 30nm; the material of the hole blocking layer 7 is TPBI with a thickness of 10nm; the material of the electron transport layer 8 is ET-1 with a thickness of 35nm; the material of the electron injection layer 9 is Liq with a thickness of 2nm; the material of the cathode layer is Al with a thickness of 100nm.

[0108] The basic material structure used in each functional layer of the device is as follows:

[0109]

[0110] The specific preparation steps of the above organic electroluminescent device are as follows:

[0111] 1) Cleaning the ITO anode on the transparent glass substrate by ultrasonic cleaning with deionized water, acetone, and ethanol for 20 minutes each, and then performing plasma treatment in an oxygen atmosphere for 5 minutes;

[0112] 2) On the ITO anode layer, a hole injection layer material HAT-CN is deposited by vacuum evaporation with a thickness of 5 nm, which serves as a hole injection layer;

[0113] 3) vacuum evaporation is performed on the hole injection layer to deposit a hole transport material NPB with a thickness of 60 nm, and this layer is used as the first hole transport layer;

[0114] 4) Vacuum evaporation of hole transport material TCTA on the first hole transport layer NPB with a thickness of 15 nm, which serves as the second hole transport layer;

[0115] 5) On the second hole transport layer, a light-emitting layer was co-deposited by vacuum evaporation, using compound 47 as the main material and BD01 as the light-emitting material, with a doping mass ratio of 5% and a thickness of 30 nm;

[0116] 6) On the light-emitting layer, a hole blocking material TPBI is deposited by vacuum evaporation with a thickness of 10 nm, and this layer serves as a hole blocking layer;

[0117] 7) On the hole blocking layer, the electron transport material ET-1 is deposited by vacuum evaporation with a thickness of 35 nm, and this layer serves as the electron transport layer;

[0118] 8) On the electron transport layer, the electron injection material Liq is deposited by vacuum evaporation with a thickness of 2 nm, and this layer serves as the electron injection layer;

[0119] 9) On the electron injection layer, cathode Al is deposited by vacuum evaporation with a thickness of 100 nm. This layer is used as a cathode conductive electrode.

[0120] Device Example 2

[0121] The same as device example 1, except that compound 52 is used as the main material instead of compound 47.

[0122] Device Example 3

[0123] Same as device embodiment 1, except that the main material is BH01 and the light-emitting material is compound 1.

[0124] Device Example 4

[0125] The same as device embodiment 3, except that the light-emitting material is compound 3.

[0126] Device Example 5

[0127] The same as device embodiment 3, except that the light-emitting material is compound 11.

[0128] Device Example 6

[0129] The same as device embodiment 3, except that the light-emitting material is compound 28.

[0130] Device Example 7

[0131] The same as device embodiment 3, except that the light-emitting material is compound 37.

[0132] Comparative Example 1

[0133] Same as device example 1, except that BH01 is used as the main material instead of compound 47.

[0134] The components of different devices prepared in device embodiments 1 to 7 and comparative example 1 of the present invention are shown in Table 2:

[0135] Table 2 Comparison of organic electroluminescent device components of various device examples

[0136]

[0137]

[0138] The cathode and anode of each group of organic electroluminescent devices are connected by a known driving circuit, and the voltage-efficiency-current density relationship of the OLED device is tested by a standard method using a Keithley 2400 power supply combined with a PR670 photometer, such as Figure 2 Device Example 6 (Compound 28 is a luminescent material) test data diagram; the device life is tested by constant current method, and the test condition is a constant current density of 10mA / cm 2 The time it takes for the brightness to decay to 90% of the initial brightness is the device LT 90 Life span, such as Figure 3 As shown, taking the life test data diagram of the device in device embodiment 6 as an example, the test methods of other devices are the same, and the test results of device embodiments 1 to 7 and comparative example 1 are shown in Table 3:

[0139] Table 3 Performance results of organic electroluminescent devices in each group

[0140]

[0141] As can be seen from Table 3, the series of compounds provided by the present invention are applied to OLED devices as blue main materials or blue luminescent materials of the light-emitting layer, and have excellent performance. For example, the compound 47 in device embodiment 1 is used as a blue light main material, compared with the comparative example 1BH01, and the luminous efficiency and service life are significantly improved, the luminous efficiency is increased by 21.2%, and the service life is increased by 30%; the compounds in device embodiments 3-7 have excellent performance as blue light luminescent materials, such as the compound 3 in embodiment 4 is compared with BD01 in comparative example 1, the luminous efficiency is increased by about 40%, the service life is increased by 52%, and the color coordinates are better. It can be seen that the compounds of the present invention are selected as the main materials or luminescent materials of OLED devices, and compared with the existing materials applied to OLED light-emitting devices, the photoelectric properties of the device such as luminous efficiency, life, color purity, etc. are all good, and the synthesis process of the material is simple. It is an excellent new blue light TADF material, which has great application value in the application of OLED devices and has good industrialization prospects.

[0142] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, they are also intended to be included.

Claims

1. An organic electroluminescent device, comprising a light-emitting layer, characterized in that: The main material of the light-emitting layer includes a pyrazine derivative, and the pyrazine derivative is any one of the following compounds:

2. Use of the organic electroluminescent device according to claim 1 in an organic electroluminescent display device.

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