Organic compound with nitrogen-containing heterocyclic ring structure as parent nucleus and organic electroluminescent device containing organic compound

Abstract

The invention provides an organic compound with a nitrogen-containing heterocyclic ring structure as a parent nucleus and an organic electroluminescent device comprising the organic compound, the structure of the organic compound is shown in the general formula I. The compound with the specific structure can effectively improve the luminous efficiency of the organic electroluminescent device, meanwhile, the driving voltage of the device is reduced, and the luminous efficiency of the organic electroluminescent device is improved. And the service life of the organic light-emitting device is prolonged.

Description

Technical Field

[0001] The present invention belongs to the technical field of semiconductor materials, and in particular relates to an organic compound whose parent core is a nitrogen-containing heterocyclic structure and an organic electroluminescent device containing the same. Background Art

[0002] Organic light emitting diode (OLED) device technology can be used to manufacture new display products and new lighting products. It is expected to replace existing liquid crystal displays and fluorescent lighting, and has a wide range of applications. OLED light-emitting devices are like sandwich structures, including electrode material films and organic functional materials sandwiched between different electrode film layers. Various functional materials are superimposed on each other according to their uses to form OLED light-emitting devices. As a current device, when a voltage is applied to the electrodes at both ends of the OLED light-emitting device, under the action of the electric field, the positive and negative charges in the organic layer functional material film layer are further compounded in the light-emitting layer, generating OLED electroluminescence.

[0003] OLED optoelectronic functional materials used in OLED devices can be divided into two categories based on their uses, namely charge injection transport materials and luminescent materials. Furthermore, charge injection transport materials can be divided into electron injection transport materials, electron blocking materials, hole injection transport materials and hole blocking materials. As charge transport materials, they are required to have good carrier mobility, high glass transition temperature, etc. For OLED devices, electrons are injected from the cathode and then transferred to the main material through the electron transport layer, where they recombine with holes to generate excitons. Therefore, improving the injection and transport capabilities of the electron transport layer is conducive to reducing the device driving voltage while obtaining efficient electron-hole recombination efficiency.

[0004] OLED has developed a variety of structures, among which a tandem OLED with multiple light-reflecting layers stacked has been developed. The tandem OLED has the following structure: a stack of multiple layers each formed by a hole injection layer (HIL) / hole transport layer (HTL) / light-emitting layer / electron transport layer (ETL) / electron injection layer (EIL) is stacked between the anode electrode and the cathode electrode. In particular, a charge generation layer (CGL) formed by NCGL and PCGL is arranged between the stack to generate charges or inject charges into the light-emitting layer.

[0005] However, in CGL, due to the energy level difference between NCGL and PCGL, the property of injecting electrons generated by charge generation at the interface between PCGL and the adjacent hole injection layer into NCGL is insufficient. In addition, when conventional NCGL is doped with alkali metal, the alkali metal diffuses into PCGL, resulting in a reduced OLED lifespan.

[0006] In view of this, the present invention is proposed. Summary of the invention

[0007] In view of the shortcomings of the prior art, the object of the present invention is to provide an organic compound having a nitrogen-containing heterocyclic structure as a parent core and an organic electroluminescent device comprising the same. The compound of the specific structure of the present invention can provide a new type of NCGL, thereby reducing the driving voltage of OLED, improving the luminous efficiency of OLED, and extending the life of OLED.

[0008] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0009] In one aspect, the present invention provides an organic compound, the structure of which is shown in Formula 1:

[0010]

[0011] X1-X4 are the same as or different from each other, and are independently selected from N or CR, and at least one of them is a N atom, and the rest are CR; preferably X1 is a N atom;

[0012] X5-X6 are the same as or different from each other and are independently selected from N or CR;

[0013] X7-X 10 are the same or different from each other, each independently selected from N or CR, and at least one of them is a N atom, and the rest are CR; preferably X 10 is N atom;

[0014] L is selected from substituted or unsubstituted C6-C24 aryl, substituted or unsubstituted C6-C24 heteroaryl, wherein the heteroatom is selected from O, N or S;

[0015] R1 is selected from deuterium, substituted or unsubstituted C6-C24 aryl, substituted or unsubstituted C6-C24 heteroaryl, wherein the heteroatom is selected from O, N or S;

[0016] Y1-Y4 are the same as or different from each other, and are independently selected from N or CR, and at least two of Y1-Y4 are N atoms, and the rest are CR;

[0017] R is selected from hydrogen, deuterium, substituted or unsubstituted C6-C24 aryl, substituted or unsubstituted C6-C24 heteroaryl, wherein the heteroatom is selected from O, N or S;

[0018] A is fused to any position of the adjacent benzene ring and is selected from phenyl or naphthyl;

[0019] The hydrogen in Formula 1 is not substituted with deuterium, partially substituted with deuterium, or completely substituted with deuterium.

[0020] Further, L is selected from substituted or unsubstituted phenylene, substituted or unsubstituted biphenyl, substituted or unsubstituted terphenyl, substituted or unsubstituted naphthyl;

[0021] Furthermore, R1 is selected from deuterium, phenyl, biphenyl, terphenyl, naphthyl, and pyridyl.

[0022] Furthermore, the organic compound has any of the following structures:

[0023] ;

[0024] ;

[0025] in Indicates the fusion position of A and the adjacent benzene ring.

[0026] The above-mentioned “substitution” is mono-substitution or poly-substitution, and the substituent is selected from D (deuterium), T (tritium), C1-C10 alkyl, C6-C24 aryl, C6-C24 heteroaryl, wherein the heteroatom is selected from O, N or S.

[0027] In the above technical solution, it is further preferred that the organic compound is any one of the following structures, but not limited thereto:

[0028]

[0029]

[0030]

[0031]

[0032]

[0033]

[0034]

[0035]

[0036]

[0037]

[0038]

[0039]

[0040]

[0041]

[0042]

[0043]

[0044]

[0045] .

[0046] Preparation method:

[0047]

[0048] Under nitrogen protection, raw material A (1.0 eq) and raw material B (1.0-1.1 eq) were put into a mixed solution of toluene, ethanol and water, followed by venting 3 times. Potassium carbonate (2.0 eq-2.5 eq) and tetrakis(triphenylphosphine)palladium (0.01 eq-0.015 eq) were added under nitrogen protection, stirred evenly, heated to 90-100°C, and refluxed for 8-10 hours. After the reaction was completed, the temperature was slightly lowered, and diatomaceous earth was used for filtration to remove salt and catalyst. After the filtrate was cooled to room temperature, it was washed with water three times, the organic phase was retained, and the aqueous phase was extracted with ethyl acetate. After the organic phases were combined, they were dried with anhydrous magnesium sulfate, and the solvent was removed with a rotary evaporator to obtain intermediate 1.

[0049] Under nitrogen protection, the intermediate 1 (1.0 eq) and the raw material C (1.0-1.1 eq) were stirred evenly in a mixed solvent of 280 mL toluene, ethanol and water (volume ratio of 2:1:1), and X-Phos (0.05 eq-1.0 eq), palladium acetate (Pd(OAc)2) (0.05 eq-1.0 eq), and cesium carbonate (2.0 eq-2.5 eq) were added. After sufficient stirring, the temperature was raised to 90-100°C and stirred for reaction for 8-10 hours. After the reaction was completed, the temperature was slightly lowered, and diatomaceous earth was used for filtration to remove salt and catalyst. After the filtrate was cooled to room temperature, it was washed with water three times, the organic phase was retained, and then the aqueous phase was extracted with ethyl acetate; after the organic phases were combined, they were dried with anhydrous magnesium sulfate, and the solvent was removed with a rotary evaporator to obtain the compound shown in the general formula 1.

[0050] In another aspect, the present invention provides an organic electroluminescent device, comprising an anode and a cathode and an organic thin film layer disposed between the anode and the cathode, wherein the organic thin film layer comprises the organic compound as described above.

[0051] Preferably, the organic thin film layer comprises a charge generation layer, and the material of the charge generation layer comprises the organic compound as described above.

[0052] Preferably, the charge generation layer includes an N-type charge generation layer and a P-type charge generation layer, and the material of the N-type charge generation layer includes the organic compound as described above.

[0053] Preferably, the organic thin film layer further comprises any one of a hole injection layer, a hole transport layer, an electron blocking layer, a light emitting layer, a hole blocking layer or an electron transport layer, or a combination of at least two thereof.

[0054] Compared with the prior art, the present invention has the following beneficial effects:

[0055] The compound provided by the present invention has efficient charge generation capability and efficient electron transport performance, and can effectively improve the luminous efficiency of the organic electroluminescent device, while reducing the device driving voltage and extending the service life of the organic electroluminescent device.

[0056] The compound of the present invention can effectively inhibit the film crystallinity of the molecule, improve the film stability and heat resistance durability of the material, and help improve the efficiency and life of the device. Furthermore, since the compound of the present invention has good electron-withdrawing ability, film stability and electron tolerance, it is used as an n-type material of the CGL layer, and can form a stable N-metal coordination bond with metals such as Li or Yb to form a stable and flat organic-metal doped film, which inhibits the oxidation of the metal and helps improve the charge generation efficiency and device stability.

[0057] When the compound of the present invention is used as an organic electroluminescent NCGL layer material in an OLED device, the device driving voltage can be effectively reduced, and the device luminous efficiency and lifespan can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 is the H NMR spectrum of compound 1. DETAILED DESCRIPTION

[0059] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0060] Example 1

[0061]

[0062] Under nitrogen protection, raw material A (1.0 eq) and raw material B (1.0 eq) were put into a mixed solution of toluene, ethanol and water (volume ratio = 2:1:1), followed by ventilating 3 times, adding potassium carbonate (2.0 eq) and tetrakis(triphenylphosphine)palladium (0.01 eq) under nitrogen protection, stirring evenly, heating to 90°C, and reflux reaction for 8 h. After the reaction was completed, the temperature was slightly lowered, and diatomaceous earth was used for filtration to remove salt and catalyst. After the filtrate was cooled to room temperature, it was washed with water three times, the organic phase was retained, and the aqueous phase was extracted with ethyl acetate; after the organic phases were combined, they were dried with anhydrous magnesium sulfate, and the solvent was removed with a rotary evaporator to obtain intermediate 1.

[0063] Under nitrogen protection, intermediate 1 (1.0 eq) and raw material C (1.1 eq) were stirred evenly in a mixed solvent of 280 mL toluene, ethanol and water (volume ratio of 2:1:1), and X-Phos (0.05 eq), palladium acetate (Pd(OAc)2) (0.05 eq), and cesium carbonate (2.0 eq) were added. After sufficient stirring, the temperature was raised to 90°C and stirred for 10 hours. After the reaction was completed, the temperature was slightly lowered, and diatomaceous earth was used for filtration to remove salt and catalyst. After the filtrate was cooled to room temperature, it was washed three times with water, the organic phase was retained, and the aqueous phase was extracted with ethyl acetate; after the organic phases were combined, they were dried with anhydrous magnesium sulfate, and the solvent was removed with a rotary evaporator to obtain compound 1 (yield: 70.2%).

[0064] The obtained compound 1 was tested and analyzed, and the results were as follows:

[0065] HPLC purity: >99.95%.

[0066] MS (ESI, m / Z): [M+H] + :561.22

[0067] Elemental Analysis:

[0068] Calculated values: C, 85.69; H, 4.31; N, 9.99.

[0069] Test values ​​are: C, 85.34; H, 4.60; N,10.22.

[0070] The H NMR spectrum of compound 1 is as follows Figure 1 shown.

[0071] Example 2

[0072]

[0073] Under nitrogen protection, raw material A (1.0 eq) and raw material B (1.1 eq) were put into a mixed solution of toluene, ethanol and water (volume ratio = 2:1:1), followed by ventilating 3 times, adding potassium carbonate (2.0 eq) and tetrakis(triphenylphosphine)palladium (0.01 eq) under nitrogen protection, stirring evenly, heating to 90°C, and reflux reaction for 8 hours. After the reaction was completed, the temperature was slightly lowered, and diatomaceous earth was used for filtration to remove salt and catalyst. After the filtrate was cooled to room temperature, it was washed with water three times, the organic phase was retained, and the aqueous phase was extracted with ethyl acetate; after the organic phases were combined, they were dried with anhydrous magnesium sulfate, and the solvent was removed with a rotary evaporator to obtain intermediate 1.

[0074] Under nitrogen protection, intermediate 1 (1.0 eq) and raw material C (1.1 eq) were stirred evenly in 280 mL of a mixed solvent of toluene, ethanol and water (volume ratio of 2:1:1), and X-Phos (0.05 eq), palladium acetate (Pd(OAc)2) (0.05 eq), and cesium carbonate (2.0 eq) were added. After sufficient stirring, the temperature was raised to 90°C and stirred for 10 hours. After the reaction was completed, the temperature was slightly lowered, and diatomaceous earth was used for filtration to remove salt and catalyst. After the filtrate was cooled to room temperature, it was washed three times with water, the organic phase was retained, and the aqueous phase was extracted with ethyl acetate; after the organic phases were combined, they were dried with anhydrous magnesium sulfate, and the solvent was removed with a rotary evaporator to obtain the general compound 13 (yield: 68.2%).

[0075] The obtained compound 13 was tested and analyzed, and the results were as follows:

[0076] HPLC purity: >99.95%.

[0077] MS (ESI, m / Z): [M+H] + :561.21

[0078] Elemental Analysis:

[0079] Calculated values: C, 85.69; H, 4.31; N, 9.99.

[0080] Test values ​​are: C, 85.22; H, 4.59; N, 10.18.

[0081] The synthesis methods of other compounds are the same as those in the above examples and are not described in detail here.

[0082] Device application example 1: Preparation of organic electroluminescent devices

[0083] Anode: ITO anode: Wash the ITO (indium tin oxide)-Ag-ITO (indium tin oxide) glass substrate with a coating thickness of 150nm in distilled water twice, ultrasonically wash for 30 minutes, and then repeatedly wash it with distilled water twice, ultrasonically wash for 10 minutes. After washing, bake it in a vacuum oven at 220℃ for 2 hours. After baking, cool it down and it can be used. Use this substrate as the anode, use an evaporation machine to carry out the evaporation device process, and evaporate other functional layers on it in sequence.

[0084] First hole injection layer: On the washed anode layer, HT-1 and P-1 with a thickness of 10 nm were evaporated by vacuum evaporation equipment, and the mass ratio of HT-1 to P-1 was 97:3 as the first hole injection layer;

[0085] First hole transport layer: On the first hole injection layer, HT-1 was then evaporated to a thickness of 24 nm as the first hole transport layer.

[0086] First electron blocking layer: EB-1 with a thickness of 5 nm was then evaporated on the first hole transport layer as the first electron blocking layer.

[0087] First light-emitting layer: After the evaporation of the first electron blocking material is completed, the light-emitting layer of the OLED light-emitting device is manufactured. The structure includes the OLED light-emitting layer using BH-1 as the main material and BD-1 as the doping material. The doping ratio of the doping material is 3% by weight, and the thickness of the light-emitting layer is 20nm.

[0088] First hole blocking layer: after the first light-emitting layer, 5 nm of HB-1 was evaporated as the first hole blocking layer;

[0089] First electron transport layer: After the first hole blocking layer, 10 nm of ETM-1 and Liq were vacuum evaporated, and the mass ratio of ETM-1:Liq was 1:1 as the first electron transport layer.

[0090] NCGL layer: On the first electron transport layer, an N-type charge generation layer (NCGL layer) was evaporated by a vacuum evaporation device, wherein the mass ratio of compound 1:Yb was 95:5 and the film thickness was 20 nm.

[0091] PCGL layer: On the NCGL layer, a co-evaporation layer of HT-1 and P-1 with a film thickness of 10 nm was evaporated using a vacuum evaporation device, and the mass ratio of HT-1 to P-1 was 95:5 as a P-CGL layer.

[0092] Second hole transport layer: HT-1 with a film thickness of 30 nm was then evaporated as the second hole transport layer.

[0093] Second electron blocking layer: EB-1 with a thickness of 5 nm was then evaporated on the second hole transport layer as the second electron blocking layer.

[0094] Second light-emitting layer: After the second electron blocking material is evaporated, the second light-emitting layer of the OLED light-emitting device is prepared. Its structure includes the OLED second light-emitting layer using BH-1 as the main material and BD-1 as the doping material. The doping ratio of the doping material is 3% by weight, and the light-emitting layer film thickness is 20nm.

[0095] Second hole blocking layer: After the second light-emitting layer, continue to vacuum evaporate 5nm of HB-1. This layer is the second hole blocking layer.

[0096] Second electron transport layer: On the second hole blocking layer, 15 nm of ETM-1 and Liq were evaporated, and the mass ratio of ETM-1:Liq was 1:1 as the second electron transport layer.

[0097] Second electron injection layer: On the second electron transport layer, YB with a film thickness of 1 nm was produced by vacuum evaporation equipment as the second electron injection layer.

[0098] Cathode: A 13nm Mg:Ag electrode layer was evaporated, with a mass ratio of Mg to Ag of 1:9. This layer is the cathode layer.

[0099] Light extraction layer: CPL-1 with a thickness of 65 nm is vacuum-deposited on the cathode as a light extraction layer;

[0100] The vapor-deposited substrate is packaged; first, the cleaned cover plate is coated with UV glue using a glue coating device, and then the coated cover plate is moved to the pressing section, and the vapor-deposited substrate is placed on the upper end of the cover plate, and finally the substrate and the cover plate are bonded by the bonding equipment, and the UV glue is cured by light.

[0101] The structural formula of the materials used is shown below:

[0102]

[0103] Device Application Examples 2 to 52: Referring to the above method, the compound 1 used in the device application example 1 is replaced by compound 13, compound 2, compound 5, compound 8, compound 9, compound 11, compound 22, compound 28, compound 30, compound 35, compound 41, compound 46, compound 51, compound 54, compound 57, compound 63, compound 69, compound 72, compound 78, compound 81, compound 89, compound 95, compound 100, compound 105, compound 109, compound 113, and compound 114. Compound 118, compound 124, compound 130, compound 133, compound 139, compound 145, compound 148, compound 154, compound 157, compound 160, compound 169, compound 179, compound 182, compound 208, compound 220, compound 229, compound 238, compound 242, compound 249, compound 254, compound 258, compound 263, compound 267, compound 272, and compound 278 are used as compounds in the NCGL layer to prepare the corresponding organic electroluminescent devices.

[0104] Device Comparative Example: This comparative example provides an organic electroluminescent device. The only difference between the preparation method of the organic electroluminescent device and the device example 1 is that the organic electroluminescent device uses existing comparative compounds a and b to replace the compound 1 in the NCGL layer in the device example 1 for evaporation to prepare the device of device comparative example 1-2. The chemical structural formulas of comparative compounds a and b are as follows:

[0105] .

[0106] The driving voltage, luminous efficiency and life of the organic electroluminescent devices obtained from the device embodiments 2-52 and the device comparative examples 1-2 were characterized at a brightness of 1000 (nits). The test results are shown in Table 1 below.

[0107] Table 1

[0108]

[0109]

[0110] As can be seen from Table 1, in the stacked device, the compound provided by the present invention has a nitrogen-containing heterocycle as the parent core structure, has efficient charge generation capability and efficient electron transport performance, can effectively improve the luminous efficiency of the organic electroluminescent device, while reducing the device driving voltage and extending the service life of the organic electroluminescent device. When used as an NCGL material, compared with the comparative compound, the device voltage is reduced, and the device efficiency and device life are improved, which further shows that the compound of the present invention has good technical effects when used as an NCGL material in a stacked OLED device.

[0111] The applicant declares that the present invention uses the above-mentioned embodiments to illustrate the organic compound and the organic electroluminescent device of the present invention, but the present invention is not limited to the above-mentioned embodiments, that is, it does not mean that the present invention must rely on the above-mentioned embodiments to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of the raw materials selected by the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. An organic compound, characterized in that The structure of the organic compound is shown in Formula 1: ； X1-X4 are the same as or different from each other, and are independently selected from N or CR, and at least one of them is a N atom, and the rest are CR; X5-X6 are the same as or different from each other and are independently selected from N or CR; X7-X 10 are the same as or different from each other, and are independently selected from N or CR, and at least one of them is a N atom, and the rest are CR; L is selected from substituted or unsubstituted C6-C24 aryl, substituted or unsubstituted C6-C24 heteroaryl, wherein the heteroatom is selected from O, N or S; R1 is selected from deuterium, substituted or unsubstituted C6-C24 aryl, substituted or unsubstituted C6-C24 heteroaryl, wherein the heteroatom is selected from O, N or S; Y1-Y4 are the same as or different from each other, and are independently selected from N or CR, and at least two of Y1-Y4 are N atoms, and the rest are CR; R is selected from hydrogen, deuterium, substituted or unsubstituted C6-C24 aryl, substituted or unsubstituted C6-C24 heteroaryl, wherein the heteroatom is selected from O, N or S; A is fused to any position of the adjacent benzene ring, and A is selected from phenyl or naphthyl; The hydrogen in Formula 1 is not substituted with deuterium, partially substituted with deuterium, or completely substituted with deuterium.

2. The organic compound according to claim 1, characterized in that X1 is a N atom; X 10 is a N atom.

3. The organic compound according to claim 1, characterized in that L is selected from a substituted or unsubstituted phenylene group, a substituted or unsubstituted biphenyl group, a substituted or unsubstituted terphenyl group, and a substituted or unsubstituted naphthyl group.

4. The organic compound according to claim 1, characterized in that R1 is selected from deuterium, phenyl, biphenyl, terphenyl, naphthyl, pyridyl.

5. The organic compound according to claim 1, characterized in that The organic compound has any of the following structures: ； ； in Indicates the fusion position of A and the adjacent benzene ring.

6. The organic compound according to claim 1, characterized in that The substituents in the substituted C6-C24 aryl and substituted C6-C24 heteroaryl are selected from deuterium, tritium, C1-C10 alkyl, C6-C24 aryl, C6-C24 heteroaryl, wherein the heteroatom is selected from O, N or S.

7. The organic compound according to claim 1, characterized in that The organic compound is any one of the following compounds: 。 8. An organic electroluminescent device, characterized in that: The organic electroluminescent device comprises an anode and a cathode and an organic thin film layer disposed between the anode and the cathode, wherein the organic thin film layer comprises the organic compound according to any one of claims 1 to 7.

9. The organic electroluminescent device according to claim 8, characterized in that: The organic thin film layer comprises a charge generation layer, the charge generation layer comprises an N-type charge generation layer and a P-type charge generation layer, and the material of the N-type charge generation layer comprises the organic compound according to any one of claims 1 to 7.

10. The organic electroluminescent device according to claim 8, characterized in that: The organic thin film layer further comprises any one of a hole injection layer, a hole transport layer, an electron blocking layer, a light emitting layer, a hole blocking layer or an electron transport layer, or a combination of at least two thereof.

Images