Organic compound and organic electroluminescent device using same

Abstract

The invention discloses an organic compound and an organic light-emitting device using the same, the organic compound is applied to a light-emitting layer of an OLED (organic light-emitting diode) device, holes and electrons can be effectively balanced, and a relatively wide carrier composite region is formed, so that the light-emitting efficiency of the device is remarkably improved, the starting voltage and the energy consumption are reduced, and the organic light-emitting device is suitable for large-scale production. The device service life is prolonged.

Description

Technical Field

[0001] The present invention belongs to the technical field of organic light-emitting materials, and particularly relates to an organic compound and an organic electroluminescent device using the compound. Background Art

[0002] Organic light-emitting diode (OLED) technology, as a new generation of display and lighting solution, has been increasingly attracting wide attention in the industry due to its unique advantages such as self-luminescence, high brightness, strong contrast, and being thin, light, and bendable. OLED devices usually adopt a multi-layer structure, including a hole injection layer, a hole transport layer, an electron injection layer, an electron transport layer, and a core light-emitting layer. The light-emitting layer is composed of a host material and a guest material (i.e., a dopant), and sometimes a sensitizer is also added to optimize the energy level configuration and improve the light-emitting efficiency. The host material needs to have high stability and an appropriate energy level structure to ensure efficient energy transfer and prevent the annihilation of high-concentration excitons.

[0003] Currently, host materials are mainly divided into three categories: hole-transporting type, electron-transporting type, and bipolar-transporting materials. When using a specific type of host material, a charge recombination region will be formed at a specific layer interface. However, the mismatch of carrier mobilities and the limitation of the charge recombination region will have an adverse effect on the light-emitting efficiency. Especially at high current densities, the triplet annihilation phenomenon will be aggravated, thereby reducing the light-emitting efficiency. To solve this problem, commonly adopted strategies include using a double-layer light-emitting structure or a mixed host material, but these methods will increase the complexity of the manufacturing process and the risk of phase separation. Bipolar host materials have shown unique advantages in the OLED field because they can balance the transport of holes and electrons, and simplify the device structure. In 2015, Doosan Group (DOOSAN) in South Korea disclosed a class of novel organic light-emitting compounds as shown in the formula in its patent with the publication number KR101603388B1. These compounds are used as bipolar host materials in electroluminescent devices, can be well matched with phosphorescent guest materials of different colors, and at the same time achieve a relatively high current efficiency. However, the driving voltage of this device is relatively high, which has a greater impact on the service life of the device; in addition, the doping ratio of the phosphorescent guest material is also relatively high (up to 10%), which may lead to a decrease in the energy transfer efficiency between the host material and the guest material, not only affecting the light-emitting efficiency, but also possibly damaging the stability of the material, thus shortening the life of the device. Currently, the development of high-performance bipolar host materials is far from meeting the market demand. Therefore, it is particularly important to develop higher-performance bipolar host materials.

[0004] Summary of the Invention

[0005] ​The object of the present invention is to overcome the deficiencies of the above-mentioned prior art, and provide an organic compound and an organic electroluminescent device using the compound.

[0006] To solve the above technical problems, the technical solution of the present invention is: an organic compound, the organic compound has a structure shown in General Formula 1:

[0007]

[0008] Wherein:

[0009] Z 1 is selected from an O atom, an S atom, an N atom substituted by an aryl or heteroaryl group of C 6 ~C 12 an alkyl-substituted C atom of C 1 ~C 6 an aryl-substituted C atom of C 6 ~C 12 an alkyl-substituted Si atom of C 1 ~C 6 or an aryl-substituted Si atom of C 6 ~C 12 The heteroaryl group of C 6 ~C 12 includes a pyridyl group and a pyrimidinyl group;

[0010] Z 2 is selected from an O atom or an S atom;

[0011] L is selected from an aryl group of C 6 ~C 30 or a heteroaryl group of C 4 ~C 30 The bonding mode of L to the main structure is a single bond; the heteroatoms of the heteroaryl group of C 4 ~C 30 in L include O, S or N, and the heteroaryl group of C 4 ~C 30 in L includes a monocyclic heteroaryl group, a polycyclic heteroaryl group and a fused-ring heteroaryl group.

[0012] X 1 、X 2 、X 3 、X 4 are each independently selected from an N atom or a C atom, and satisfy the following conditions:

[0013] When X 1 and X 3 are both N atoms at the same time, X 2 and X 4 can only be C atoms. At this time, L is bonded to X 2or X 4 above;

[0014] When X 2 and X 4 are both N atoms, X 1 and X 3 can only be C atoms. At this time, L is bonded to X 1 or X 3 above.

[0015] In the present invention, the term "aryl" refers to a monocyclic or fused polycyclic (i.e., rings sharing adjacent carbon atom pairs) group of all-carbon atoms having a conjugated π-electron system.

[0016] In the present invention, the term "heteroaryl" refers to the general term of groups obtained by replacing one or more aryl nuclear carbon atoms or non-aryl nuclear carbon atoms in aryl with heteroatoms. The heteroaryl can be a monocyclic heteroaryl, a polycyclic heteroaryl or a fused heteroaryl.

[0017] The aryl of C 6 ~C 30 in L includes but is not limited to phenyl, naphthyl, biphenyl, etc.

[0018] Preferably, the said L is selected from the following groups L 1 ~L 40 or any one of its derivatives:

[0019]

[0020]

[0021] Preferably, in the said groups L 1 ~L 40 ,"*" represents the bonding position of L to the main structure . Among them, the groups L 3 , L 5 , L 6 , L 7 , L 9 , L 14 , L 16 , L 17 , L 19 , L 20 , L 21 , L 22 , L 23 , L 24 , L 28 , L 29 , L 35 , L 36 , L 37 , L 38 , L 39 , L 40Bonded to the main structure only through one "*" bonding

[0022] Preferably, the organic compound is selected from any one of the following compounds 1-240:

[0023]

[0024]

[0025]

[0026]

[0027]

[0028]

[0029]

[0030]

[0031]

[0032]

[0033]

[0034]

[0035] An electroluminescent device, the electroluminescent device comprising a cathode, an anode, and an organic layer located between the cathode and the anode, the organic layer comprising a hole transport layer, a light-emitting layer, and an electron transport layer, the light-emitting layer comprising a host light-emitting material and a guest light-emitting material, and the host light-emitting material comprising any one of the organic compounds.

[0036] Preferably, the guest light-emitting material is selected from excellent-performance fluorescent materials One of them, and the mass fraction of the guest light-emitting material in the entire light-emitting layer is 0.5% to 3.0%.

[0037] Preferably, the guest light-emitting material is selected from excellent-performance phosphorescent materials One of them, and the mass fraction of the guest light-emitting material in the entire light-emitting layer is 0.01% to 1.0%.

[0038] Preferably, the electroluminescent device is applied to the fields of light-emitting illumination, image display, or optoelectronic signal transmission.

[0039] Compared with the prior art, the advantages of the present invention are as follows:

[0040] (1) In the present invention, the organic compound is ingeniously incorporated with an electron donor unit D (Donat) and an electron acceptor unit A (Accept), and a building unit with large steric hindrance is introduced. Such a design not only realizes the effective regulation of the LUMO and HOMO energy levels of the molecule, but also ensures the stability of the molecular structure, and at the same time precisely adjusts the energy level distribution inside the molecule.

[0041] (2) When the preferred compound in the present invention is used as the bipolar host material of the light-emitting layer of the OLED device, it can effectively balance the hole and electron transport while forming a relatively wide carrier recombination region, thereby significantly improving the light-emitting efficiency of the device, reducing the turn-on voltage and energy consumption, and further extending the service life of the device. In addition, the organic functional layer using the bipolar material helps to simplify the device structure and reduce the production cost.

[0042] (3) The preferred compound in the present invention, as a bipolar host material, is not only compatible with the fluorescent guest material, but also has good compatibility with the phosphorescent guest material, especially phosphorescent guest materials of different colors.

[0043] (4) Through comparative analysis, the device data prepared by using the preferred compound in the present invention and the compound Inv-407 in the patent with the publication number KR101603388B1 as the host material of the light-emitting layer respectively show that the device prepared by using the preferred compound in the present invention performs more excellently in the comprehensive light-emitting performance. Brief Description of the Drawings

[0044] Figure 1 is a cross-sectional view of an electroluminescent device of the present invention;

[0045] Figure 2 is the NMR spectrum of Compound 3 of the present invention;

[0046] Figure 3 is the NMR spectrum of Compound 35 of the present invention.

[0047] Description of the Reference Numerals:

[0048] 1. Polymer substrate, 2. Anode 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 layer, 11. Cover layer. Detailed Embodiments

[0049] The following describes the specific embodiments of the present invention in conjunction with the examples. The raw materials and reagents described in the present invention are all commercially available.

[0050] The specific process of synthesizing the organic compounds described in the present invention is introduced as follows:

[0051] The structures of the key intermediates involved in the present invention are shown in Table 1.

[0052] Table 1 Structures of the key intermediates involved in the present invention

[0053]

[0054]

[0055] The synthesis processes of some important intermediates are as follows:

[0056] Synthesis of Intermediate M1:

[0057]

[0058] Step 1:

[0059] Operation process: Under a nitrogen atmosphere, successively add o-dibromobenzene (136 g, 0.7 mol), 2.0 L of DMF, 9-hydroxyphenanthrene (198 g, 0.84 mol), cesium carbonate (Cs2CO3, 272 g, 1.4 mol), tetrakis(triphenylphosphine)palladium (Pd(PPh3)4, 24 g, 0.1 mol), and triphenylphosphine (PPh 3， 110 g, 0.6 mol) into a 5 L three-necked flask. After starting stirring, heat the reaction solution to 140 °C and maintain this temperature for 12 h. After the reaction is completed, concentrate the solvent, and then extract it multiple times with an appropriate amount of dichloromethane and water. Combine the organic phases, dry the collected organic phases with anhydrous magnesium sulfate, filter and concentrate. The residue is purified by silica gel column chromatography (using ethyl acetate / petroleum ether as the eluent) to obtain 113 g of M1-1, with a yield of 60%, an HPLC purity of 98%, and the LC-MS shows a molecular weight of 269.1.

[0060] Step 2:

[0061] Operation process: Under a nitrogen atmosphere, successively add M1-3 (107 g, 0.4 mol) and 3.0 L of 1,4-dioxane into a 10 L three-necked flask. Add 300 mL of 38.5% dilute nitric acid and react at 60 °C for 1 h until the reaction is complete. After the reaction is completed, concentrate under reduced pressure to remove 1,4-dioxane, then add an appropriate amount of water and dichloromethane for extraction. The organic phase is dried with anhydrous MgSO 4 and filtered and concentrated. The residue is purified by silica gel column chromatography (using ethyl acetate / petroleum ether as the eluent) to obtain 74 g of Intermediate M1-2, with a yield of 59%, an HPLC purity of 98%, and the LC-MS shows a molecular weight of 314.1.

[0062] Step 3:

[0063] Operation procedure: Under a nitrogen atmosphere, add M1-2 (74 g, 0.24 mol), triphenylphosphine (124 g, 0.47 mol), and 1200 mL of 1,2-dichlorobenzene into a 5 L three-necked flask in sequence. Stir the reaction mixture at room temperature for 12 h until the reaction is complete. After the reaction is completed, concentrate under reduced pressure to remove 1,2-dichlorobenzene, then add appropriate amounts of water and dichloromethane for extraction. The organic phase is dried over anhydrous MgSO 4 4, filtered, and concentrated. The residue is purified by silica gel column chromatography (using ethyl acetate / petroleum ether as the eluent) to obtain 45 g of intermediate M1, with a yield of 68% and an HPLC purity of 98%. LC-MS shows a molecular weight of 282.1.

[0064] Synthesis of intermediate M2:

[0065]

[0066] Step 1:

[0067] Operation procedure: Under a nitrogen atmosphere, add 9-bromophenanthrene (257 g, 1.0 mol), 2-aminothiophenol (150 g, 1.2 mol), potassium carbonate (276 g, 2.0 mol), and 5.0 L of DMF into a 5 L three-necked flask in sequence. Heat the reaction mixture to 150 °C and continue the reaction for 80 h until the reaction is complete. After the reaction is completed, remove most of the DMF by concentration under reduced pressure, then add appropriate amounts of water and dichloromethane for extraction. The organic phase is dried over anhydrous MgSO 4 4, filtered, and concentrated. The residue is purified by silica gel column chromatography (using ethyl acetate / petroleum ether as the eluent) to obtain 229 g of intermediate M2-1, with a yield of 76% and an HPLC purity of 98%. LC-MS shows a molecular weight of 302.0.

[0068] Step 2:

[0069] Operation procedure: Take a 5 L three-necked flask and add intermediate M2-1 (229 g, 0.76 mol), 195 mL of HCl, 1950 mL of acetic acid, and 650 mL of H 2 2O in sequence. Cool the system to 0 °C in an ice-salt bath, then slowly add dropwise 500 mL of an aqueous solution of NaNO 2 (367 g, 5.32 mol). After the addition is complete, transfer the system to room temperature and react for 12 h for standby.

[0070] Meanwhile, take another 15 L three-necked flask and add CuSO 4A solution of (546 g, 3.42 mol) in 5.0 L of an aqueous hydrochloric acid solution with a volume fraction of 5.5% was slowly added to this system. The system was heated to the reflux temperature and stirred for 1 h until the reaction was complete. After the reaction was completed, the reaction solution was allowed to cool naturally to room temperature. At this time, a large amount of solid precipitated. The solid was filtered, washed with pure water, and dried to obtain intermediate M2-2, weighing 203 g, with a yield of 94% and an HPLC purity of 98%. LC-MS showed a molecular weight of 285.0. Step three:

[0071] Operation process: The synthesis of intermediate M2-3 was carried out with reference to the synthesis process of intermediate M1-2. Charge M2-3 (142 g, 0.5 mol) to obtain intermediate M2-3, weighing 91 g, with a yield of 58% and an HPLC purity of 98%. LC-MS showed a molecular weight of 330.0.

[0072] Step four:

[0073] Operation process: The synthesis of intermediate M2 was carried out with reference to the synthesis process of intermediate M1. Charge M2-3 (96 g, 0.29 mol) to obtain the final intermediate M2, weighing 58 g, with a yield of 67% and an HPLC purity of 98%. LC-MS showed a molecular weight of 298.0.

[0074] Synthesis of intermediate M3:

[0075]

[0076] Step one:

[0077] Operation process: Under a nitrogen atmosphere, N-(8-bromobenzo[a]naphthalen-9-yl)acetamide (314 g, 1.0 mol), o-methoxyphenylboronic acid (182 g, 1.2 mol), 4 L of tetrahydrofuran (THF), 1 L of H 2 O, potassium carbonate (K 2 CO 3， 415 g, 3.0 mol) were successively added to a 10 L three-necked flask, stirred and heated to 40 °C. After the solution became clear, tetrakis(triphenylphosphine)palladium (Pd(PPh 3 ) 4， 35 g, 0.03 mol) was added. After addition, the reaction solution was heated to 80 °C and continuously reacted for 12 h. After the reaction was completed, it was filtered while hot using diatomaceous earth. After the filtrate was cooled to room temperature, an appropriate amount of ethyl acetate and water were added for multiple extractions. The organic phases were combined, the organic phase was collected, dried over anhydrous magnesium sulfate, filtered and concentrated. The residue was purified by silica gel column chromatography (using ethyl acetate / petroleum ether as the eluent) to obtain 273 g of light yellow solid M3-1, with a yield of 80% and an HPLC purity of 98%. LC-MS showed a molecular weight of 342.1.

[0078] Step 2:

[0079] Operation process: Under a nitrogen atmosphere, add M3-1 (229 g, 0.7 mol), 1.5 L of 95% ethanol, and 0.9 L of 80% hydrazine hydrate to a 5-L three-necked flask in sequence. After starting stirring, hydrazine hydrate and ethanol azeotropically boil, the reaction temperature rises to the reflux temperature, and the reaction continues for 40 h until the reaction is complete. After the reaction is completed, cool the reaction solution to room temperature, add dichloromethane for extraction, dry and concentrate the organic phase, and purify the residue by silica gel column chromatography (using ethyl acetate / petroleum ether as the eluent) to obtain 174 g of light yellow solid M3-2, with a yield of 93%, an HPLC purity of 98%, and an LC-MS showing a molecular weight of 268.0.

[0080] Step 3:

[0081] Operation process: Under a nitrogen atmosphere, add M3-2 (174 g, 0.65 mol), chlorobenzene (73 g, 0.65 mol), and 2.5 L of toluene to a 5-L three-necked flask. After stirring until the solution is clear, add the catalyst tris(dibenzylideneacetone)dipalladium Pd 2 (dba) 3 (11.9 g, 0.013 mol), ligand Am-Phos (8.6 g, 0.033 mol), and sodium tert-butoxide (125 g, 1.3 mol). Heat the reaction solution to 120 °C and continue the reaction for 10 h. After the reaction is completed, filter while hot using diatomaceous earth. After the filtrate is cooled to room temperature, add purified water for washing. After liquid separation, retain the organic phase. Then extract the aqueous phase with dichloromethane, combine the organic phases, dry and concentrate with anhydrous magnesium sulfate. Purify the residue by silica gel column chromatography (using ethyl acetate / petroleum ether as the eluent) to obtain 179 g of intermediate M3-3, with a yield of 80%, an HPLC purity of 98%, and an LC-MS showing a molecular weight of 344.0.

[0082] Step 4:

[0083] Operation process: The synthesis of intermediate M3-4 is carried out with reference to the synthesis process of M1-2. Charge M3-3 (172 g, 0.5 mol) to obtain 117 g of intermediate M3-4, with a yield of 60%, an HPLC purity of 98%, and an LC-MS showing a molecular weight of 389.0.

[0084] Step 5:

[0085] Operation process: The synthesis of intermediate M3 is carried out with reference to the synthesis process of intermediate M1. Charge M3-4 (117 g, 0.3 mol) to obtain 71 g of intermediate M3, with a yield of 66%, an HPLC purity of 98%, and an LC-MS showing a molecular weight of 357.0.

[0086] Synthesis of Intermediate M4:

[0087]

[0088] Operation process: The synthesis steps of Intermediate M4 are basically the same as those of the process of synthesizing M3 from Intermediate M3-2. The only difference is that chlorobenzene is replaced by 2-chloropyridine, while all other reaction conditions remain unchanged. Therefore, the specific synthesis process will not be elaborated in detail here.

[0089] Synthesis of Intermediate M5:

[0090]

[0091] Operation process: The synthesis process of Intermediate M5 is basically the same as those of the process of synthesizing M3 from Intermediate M3-2. The only difference is that chlorobenzene is replaced by 2-chloropyridine, while all other reaction conditions remain unchanged. Therefore, the specific synthesis process will not be elaborated in detail here.

[0092] Synthesis of Intermediate M6:

[0093]

[0094] Step 1:

[0095] Operation process: Under a nitrogen atmosphere, 2,4-dichlorobenzofuro[3,2-D]pyrimidine (24 g, 0.1 mol), M1 (28 g, 0.1 mol), tris(dibenzylideneacetone)dipalladium Pd 2 (dba) 3 (1.8 g, 2 mmol), tri-tert-butylphosphine P(t-Bu) 3 (1.0 g, 5 mmol), sodium tert-butoxide (19 g, 0.2 mol), and 200 mL of toluene were successively added into a 500 mL three-necked flask. After starting stirring, the reaction solution was heated to 110 °C and continuously reacted for 8 h until the reaction was complete. After the reaction ended, the reaction solution was cooled to room temperature, the insoluble substances were filtered off, the filtrate was washed with water, and the organic phase was obtained after liquid separation. It was dried, filtered, and concentrated. The residue was purified by silica gel column chromatography (using ethyl acetate / petroleum ether as the eluent) to obtain 30 g of Intermediate M6-1, with a yield of 61%, an HPLC purity of 99%, and the LC-MS showing a molecular weight of 484.0.

[0096] Step 2:

[0097] Operation process: Under a nitrogen atmosphere, add M6-1 (30 g, 0.06 mol), bis(pinacolato)diboron (19 g, 0.075 mol), potassium acetate (13.6 g, 0.14 mol), and 200 mL of 1,4-dioxane into a 500 mL three-necked flask in sequence. After starting stirring, heat the reaction solution to 65 °C, and then add [1,1'-bis(diphenylphosphino)ferrocene]dichloropalladium Pd(dppf)Cl 2 (0.51 g, 6 mmol). Heat the reaction to 100 °C and continue the reaction for 8 h until the reaction is complete. After the reaction is completed, directly filter off the insoluble substances, collect the filtrate and concentrate it under reduced pressure to dryness. Then dissolve the concentrate with 100 mL of toluene, wash it with water, separate the organic phase after liquid separation, dry and concentrate it. After the residue is subjected to silica gel column chromatography, concentrate it under reduced pressure again until a solid precipitates. Stop concentration, cool the system to 10 - 15 °C for crystallization. After crystallization is completed, filter and drain it to obtain 27 g of intermediate M6, with a yield of 75% and an HPLC purity of 99%. LC-MS shows a molecular weight of 576.2.

[0098] Synthesis of intermediates M7 - M15:

[0099] The synthesis process of intermediates M7 - M15 is basically the same as that of intermediate M6, and the specific synthesis steps are not elaborated in detail here.

[0100] Using the above important intermediates, the synthesis implementation processes of the preferred compound 3 and compound 35 are exemplified as follows:

[0101] Synthesis of compound 3:

[0102]

[0103] Operation process: Under a nitrogen atmosphere, add M6 (5.8 g, 0.01 mol), 1-chloronaphthalene (1.6 g, 0.01 mol), 40 mL of tetrahydrofuran (THF), and 10 mL of H 2 O into a 100 mL three-necked flask in sequence. Then add potassium carbonate (K 2 CO 3 )(4.1 g, 0.03 mol), and start stirring. Heat the solution to 40 °C until it becomes clear. At this time, add Pd(PPh 3 ) 4(0.35 g, 0.3 mmol). After adding the catalyst, the reaction solution was heated to 80 °C and reacted for 12 h until the reaction was completed. After the reaction, the reaction solution was cooled to room temperature, then 150 mL of ethyl acetate was added for extraction in 3 portions, 50 mL each time. The extracted organic phases were combined, dried and concentrated. The residue was purified by silica gel column chromatography (using ethyl acetate / petroleum ether as the eluent) to obtain 4.3 g of compound 3, with a yield of 75% and an HPLC purity of 99%. LC-MS showed a molecular weight of 576.1.

[0104] 1H NMR data of compound 3: 1H NMR (500 MHz, CD 3 OD) δ 8.97 (s, 1H), 8.81 (s, 1H), 8.73 (s, 1H), 8.15 (s, 1H), 8.00 (s, 1H), 7.94 (d, J = 5.0 Hz, 2H), 7.90 (s, 1H), 7.83 (d, J = 10.0 Hz, 2H), 7.66 (dd, J = 21.8, 13.2 Hz, 4H), 7.47 (s, 2H), 7.42 (s, 1H), 7.36 (s, 1H), 7.25–7.14 (m, 3H).

[0105] Synthesis of compound 35:

[0106]

[0107] Procedure: Under a nitrogen atmosphere, M6-1 (4.8 g, 0.01 mol) and deuterated carbazole (1.8 g, 0.01 mol) were successively added to a 100 mL three-necked flask, then 50 mL of toluene was added as a solvent. Stirring was started and continued for 10 min until the solution became clear. Then tris(dibenzylideneacetone)dipalladium Pd 2 (dba) 3 (0.18 g, 0.2 mmol) and Am-Phos (0.13 g, 0.5 mmol) were added as catalysts, and sodium tert-butoxide (1.9 g, 0.02 mol) was added as a base. Subsequently, the reaction solution was heated to 110 °C and reacted for 10 h until the reaction was complete. After the reaction, insoluble substances were filtered off while hot using diatomaceous earth. After the filtrate was cooled to room temperature, purified water was added for washing. After liquid separation, the organic phase was retained. For the aqueous phase, 150 mL of ethyl acetate was added for extraction in 3 portions, 50 mL each time. The extracted organic phases were combined, dried with anhydrous magnesium sulfate and then concentrated. The residue was purified by silica gel column chromatography (using ethyl acetate / petroleum ether as the eluent) to obtain 4.8 g of compound 35, with a yield of 77% and an HPLC purity of 99%. LC-MS showed a molecular weight of 623.2.

[0108] 1H NMR data of Compound 35: 1H NMR (500 MHz, CD 3 OD) δ 9.19 (s, 1H), 8.60 (s, 1H), 8.15 (s, 1H), 7.95 (s, 1H), 7.90 (s, 1H), 7.69 (d, J = 8.1 Hz, 2H), 7.64 (d, J = 10.0 Hz, 2H), 7.42 (s, 1H), 7.36 (s, 1H), 7.24–7.14 (m, 3H).

[0109] The synthesis of other compounds refers to the synthesis processes of Compound 3 and Compound 35. The important starting materials involved in the present invention are summarized in Table 2 as follows.

[0110] Table 2 Important starting materials involved in the present invention

[0111]

[0112]

[0113] As Figures 2-3 shown are the NMR spectra of Compound 3 and Compound 35.

[0114] An introduction to the process of an organic electroluminescent device using this compound is as follows:

[0115] Among them, an organic compound of the present invention is used as the bipolar host luminescent material in the light-emitting layer. The basic structure and preparation method of the device both adopt conventional device preparation process technologies. The schematic diagram of the device structure is as Figure 1 shown. The manufacturing method of the test device is specifically introduced as follows:

[0116] As Figure 1 shown is the schematic diagram of the test device structure of the experimental process described in the present invention, which specifically includes: polymer substrate 1, anode layer 2 (ITO conductive glass), hole injection layer 3 material (HIL), hole transport layer 4 (HTL), electron blocking layer 5 (EBL), light-emitting layer 6 (EmL, using the organic compound of the present invention as the host luminescent material), hole blocking layer 7 (HBL), electron transport layer 8 (ETL), electron injection layer 9 (EIL), cathode layer 10 (Mg(10%)-Ag(90%) alloy), and high refractive index cover layer 11.

[0117] A detailed description of the device preparation process is as follows:

[0118] First, deposit a certain thickness of indium tin oxide on a pre-treated and cleaned polymer substrate (with high mechanical strength, excellent thermal stability, excellent waterproof property, excellent transparency, etc.) as the anode. Then, according to the device structure characteristics, deposit different functional layers and organic functional layer materials with set thicknesses in sequence. After the deposition of the electron injection layer material is completed, continue to sputter-deposit a magnesium-silver alloy as the cathode at a low temperature. After the cathode sputtering is completed, deposit a layer of high refractive index capping layer material to improve the refractive index of the cathode surface and increase the light extraction efficiency. Finally, package the test device using conventional device test packaging means to complete the entire manufacturing process.

[0119] The anode material is preferably a substance with a large work function. Anode substances that can be used in the present invention include: indium tin oxide (ITO), indium zinc oxide (IZO), tin dioxide (SnO 2 ), zinc oxide (ZnO), etc.

[0120] The cathode material is preferably a substance with a small work function. Cathode substances that can be used in the present invention include: metals or alloys such as magnesium (Mg), silver (Ag), aluminum (Al), aluminum-lithium (Al-Li), calcium (Ca), magnesium-indium (Mg-In), magnesium-silver (Mg-Ag), etc., and their organic combination methods to achieve.

[0121] The organic functional layers are distributed between the cathode and the anode, and specifically include a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, a hole blocking layer, an electron transport layer, and an electron injection layer; the light-emitting layer is located between the electron blocking layer and the hole blocking layer. The other functional layer materials are selected as corresponding functional layer materials with excellent cost performance in the industry, and the compatibility between the functional layers needs to be determined through a series of tests and screening processes.

[0122] The functional organic layers can be formed on the electrodes by various means or methods such as vacuum thermal evaporation, spin coating, printing, etc. Compounds used as the organic layers other than the light-emitting layer can be organic small molecules, organic macromolecules, and polymers, as well as their combinations.

[0123] Among them, the light-emitting layer (EmL) is co-evaporated in the form of a composite of a host and a guest light-emitting material. The host light-emitting material is selected from an organic compound of the present invention, and the guest light-emitting material is selected from a phosphorescent material One of them, and the composite ratio of the two is 99.8:0.2 at this time, or the guest light-emitting material is selected from excellent-performance fluorescent materials At this time, the compounding ratio of the two is 98:2. After the evaporation of each functional layer is completed, finally, it is encapsulated by the device encapsulation method commonly used in the industry. The sample used as the test device is prepared into a sample of 30mm×30mm, and then the luminescence performance indicators of the above samples are tested. Comparing with the test devices prepared with the commonly used host luminescent materials, the test device prepared with the compound preferably selected in the present invention: has a better lifespan when the luminescence brightness is the same, and has a higher brightness under the same test voltage.

[0124] The specific details of device preparation are introduced as follows:

[0125] Device comparative examples 1-4:

[0126] Prepare an electroluminescent device according to the following steps:

[0127] First, prepare a device structure as Figure 1 shown. Use 1.5mm thick polyethylene terephthalate (PET) plastic as the polymer substrate 1; the anode layer 2 uses 0.15mm thick indium tin oxide (ITO), and a series of washing treatments are carried out before use, including alkali washing, pure water washing, drying, and ultraviolet-ozone washing, to thoroughly remove the organic residues on the surface of the anode layer.

[0128] Next, evaporate a 20nm thick molybdenum trioxide (MoO 3 ) layer on the anode layer 2 as the hole injection layer 3 (HIL). Then evaporate a 50nm thick hole transport layer 4 (HTL) on the hole injection layer 3, and the material is selected as HT-1.

[0129] Subsequently, evaporate a 30nm thick electron blocking layer 5 (EBL) on the hole transport layer 4, and the material is selected as EB-1. Next, evaporate a 60nm thick light-emitting layer 6 (EmL) on the electron blocking layer 5. The host luminescent material in the light-emitting layer is selected from one of H1, H2 or the compound Inv-407 in the patent with the publication number KR101603388B1. The guest luminescent material is selected as the fluorescent material C-545P in comparative example 1, and the host luminescent material and the guest luminescent material are co-evaporated in a mass ratio of 98:2; in comparative examples 2-3, it is selected as the phosphorescent material Ir(ppy) 3 , and in comparative example 4, the phosphorescent material Ir(piq) 2 (acac) is selected, and the host luminescent material and the guest luminescent material are co-evaporated in a mass ratio of 99.8:0.2.

[0130] Evaporate a 10nm thick hole blocking layer 7 (HBL) on the light-emitting layer 6, and the material is selected as HB-1.

[0131] A 30-nm-thick electron transport layer 8 (ETL) is deposited on the hole blocking layer 7, and the material selected is ET-1.

[0132] A 15-nm-thick electron injection layer 9 (EIL) is deposited on the electron transport layer 8, and the material selected is lithium fluoride (LiF).

[0133] After the deposition of the electron injection layer 9 is completed, a 10-nm-thick magnesium-silver (Mg:Ag = 1:9) alloy is sputtered as the cathode 10 by means of low-temperature sputtering.

[0134] Finally, a 45-nm-thick capping layer 11 is continuously deposited on the cathode 10, and the material selected is CPL.

[0135] Finally, the above-mentioned functional layers are vacuum packaged, and the device fabrication is completed.

[0136] Detailed preparation schemes for device comparative examples 1 to 4:

[0137] Comparative example 1: Based on a PET substrate, an ITO anode, a 20-nm-thick MoO 3 hole injection layer, a 50-nm-thick HT-1 hole transport layer, a 30-nm-thick EB-1 electron blocking layer, a 60-nm-thick light-emitting layer composed of H1 and C-545P in a ratio of 98:2, a 10-nm-thick HB-1 hole blocking layer, a 30-nm-thick ET-1 electron transport layer, a 15-nm-thick LiF electron injection layer, a 10-nm-thick Mg:Ag = 1:9 alloy cathode are deposited in sequence, and finally a 45-nm-thick CPL capping layer is deposited.

[0138] Comparative example 2: The preparation process is basically the same as that of comparative example 1, except that the light-emitting layer is composed of H1 and Ir(ppy) 3 in a ratio of 99.8:0.2.

[0139] Comparative example 3: The preparation process is basically the same as that of comparative example 1, except that the light-emitting layer is composed of Inv-407 and Ir(ppy) 3 in a ratio of 99.8:0.2.

[0140] Comparative example 4: The preparation process is basically the same as that of comparative example 1, except that the light-emitting layer is composed of H1 and Ir(piq) 2 (acac) in a ratio of 99.8:0.2.

[0141] Detailed preparation scheme for the embodiments of the present invention:

[0142] Embodiments 1 to 4:

[0143] Follow the preparation process of Comparative Example 1, but replace the host luminescent material of the light-emitting layer with the preferred compounds 3, 34, 63, 87 of the present invention, and the guest luminescent material remains C-545P.

[0144] Examples 5 to 10:

[0145] Follow the preparation process of Comparative Example 2, but replace the host luminescent material of the light-emitting layer with the preferred compounds 34, 63, 87, 36, 65, 89 of the present invention, and the guest luminescent material remains Ir(ppy) 3 。

[0146] Examples 11 to 13:

[0147] Follow the preparation process of Device Comparative Example 4, but replace the host luminescent material of the light-emitting layer with the preferred compounds 35, 64, 88 of the present invention, and the guest luminescent material is Ir(piq) 2 (acac).

[0148] Examples 14 to 49:

[0149] Follow the preparation process of Device Comparative Example 2, but replace the host luminescent material of the light-emitting layer with the preferred compounds of the present invention, and the guest luminescent material remains Ir(ppy) 3 And the compounding ratio of the host luminescent material and the guest luminescent material remains unchanged. The compound numbers corresponding to the specific examples are shown in Table 3 below.

[0150] Table 3 Compound Number Table of Examples of the Present Invention

[0151] Device number Compound Device number Compound Device number Compound Device number Compound Example 14 1 Example 23 57 Example 32 135 Example 41 158 Example 15 2 Example 24 58 Example 33 138 Example 42 159 Example 16 3 Example 25 77 Example 34 139 Example 43 166 Example 17 4 Example 26 90 Example 35 141 Example 44 187 Example 18 5 Example 27 91 Example 36 143 Example 45 188 Example 19 6 Example 28 92 Example 37 145 Example 46 191 Example 20 7 Example 29 93 Example 38 149 Example 47 206 Example 21 54 Example 30 99 Example 39 150 Example 48 214 Example 22 56 Example 31 100 Example 40 152 Example 49 216

[0152] The materials of each functional layer involved in the above device preparation process can be selected from one or a combination of multiple corresponding relevant functional layer materials to complete. During the device implementation process, the specific content of each functional layer structure is introduced as follows: The host luminescent materials in the comparative examples are selected from the following materials:

[0153]

[0154] The HTL functional layer can be selected from the following materials:

[0155]

[0156] The EBL functional layer is selected from the following materials:

[0157]

[0158] The HBL functional layer material is selected from the following materials:

[0159]

[0160] The materials selected for the ETL functional layer are as follows:

[0161]

[0162] The materials selected for the cover layer are as follows:

[0163]

[0164] The statistical performance test data of the test devices and control devices prepared using the preferred compounds of the present invention are shown in Table 4:

[0165] Table 4 Statistical table of performance test data of test devices and control devices prepared with the preferred compounds of the present invention

[0166]

[0167]

[0168] Note: EQE refers to the external quantum efficiency of the electroluminescent device, and T95 refers to the decay time when the electroluminescent device reduces from the initial maximum brightness to 95% brightness under the condition of a current density of 15 mA / cm2.

[0169] As can be seen from Table 4, for the test devices (Examples 1 to 49) prepared using the preferred compounds of the present invention as the bipolar host luminescent materials, compared with Device Comparative Examples 1 to 4, the turn-on voltage is significantly reduced, the current efficiency is increased by about 40%, the LT95 life of the device is increased by about 50%, and the external quantum efficiency is increased by about 50%; this indicates that: using the preferred compounds of the present invention as the bipolar host material in the light-emitting layer of OLED devices, the comprehensive light-emitting performance of the devices is significantly improved.

[0170] Comparing Examples 8 to 10 with Examples 5 to 7 shows that host materials (Compounds 36, 65, 89) containing a carbazole structure with multiple tert-butyl substitutions can further improve the light-emitting performance of the device. This may be because the tert-butyl group, as a bulky substituent, can effectively prevent the formation of excimers caused by intramolecular attraction, thereby improving the light-emitting efficiency.

[0171] Examples 1 to 49 show that using the organic compounds of the present invention as bipolar host materials is applicable to both fluorescent guest materials and phosphorescent guest materials and different-color phosphorescent guest materials.

[0172] Applying the organic compounds of the present invention to the light-emitting layer of OLED devices can effectively balance holes and electrons, form a wider carrier recombination region, thereby significantly improving the light-emitting efficiency of the devices, reducing the turn-on voltage and energy consumption, and extending the working life of the devices.

[0173] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments, and various changes can be made without departing from the spirit of the present invention within the knowledge of those of ordinary skill in the art.

[0174] Many other changes and modifications can be made without departing from the concept and scope of the present invention. It should be understood that the present invention is not limited to the specific embodiments, and the scope of the present invention is defined by the appended claims.

Claims

1. An organic compound, characterized in that The organic compound has a structure as shown in Formula 1: in: Z1 is selected from O atoms, S atoms, C6~C 12 N atoms substituted by aryl or heteroaryl, C atoms substituted by C1-C6 alkyl, 12 C atoms substituted by aryl groups, Si atoms substituted by C1-C6 alkyl groups, or Si atoms substituted by C6-C 12 The Si atom substituted by an aryl group; the C6~C 12 The heteroaryl groups include pyridyl and pyrimidinyl; Z2 is selected from an O atom or a S atom; L is selected from C6~C 30 Aryl or C4~C 30 The heteroaryl group, L and the main structure The bonding mode is single bond bonding; C4~C 30 The heteroatom of the heteroaryl group includes O, S or N, and L has C4 to C 30 The heteroaryl group includes a monocyclic heteroaryl group, a polycyclic heteroaryl group and a condensed-ring heteroaryl group. X1, X2, X3, and X4 are each independently selected from N atoms or C atoms and satisfy the following conditions: When X1 and X3 are both N atoms, X2 and X4 can only be C atoms, and L is bonded to X2 or X4 through a single bond; When X2 and X4 are both N atoms, X1 and X3 can only be C atoms, and L is bonded to X1 or X3 through a single bond.

2. The organic compound according to claim 1, characterized in that The L is selected from the group L1 to L 40 or any of its derivatives: The groups L1 to L 40 In the formula, "*" indicates that L and the main structure Bonding location.

3. The organic compound according to claim 2, characterized in that The organic compound is selected from any one of compounds 1-240:

4. An electroluminescent device, characterized in that: The electroluminescent device comprises a cathode, an anode and an organic layer located between the cathode and the anode, the organic layer comprises a hole transport layer, a light-emitting layer and an electron transport layer, the light-emitting layer comprises a host light-emitting material and a guest light-emitting material, and the host light-emitting material comprises any one of the organic compounds described in claim 3.

5. An electroluminescent device according to claim 4, characterized in that: The guest luminescent material is selected from fluorescent materials with excellent performance The mass fraction of the guest luminescent material in the whole luminescent layer is 0.5% to 3.0%.

6. An electroluminescent device according to claim 4, characterized in that: The guest luminescent material is selected from phosphorescent materials with excellent performance The mass fraction of the guest luminescent material in the whole luminescent layer is 0.01% to 1.0%.

7. An electroluminescent device according to any one of claims 4 to 6, characterized in that: The electroluminescent device is applied to the fields of luminous illumination, image display or photoelectric signal transmission.

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