An organic compound having a nitrogen-containing heterocyclic structure as a parent core and an organic electroluminescent device containing the same

Abstract

The present invention provides an organic compound having a nitrogen-containing heterocyclic structure as a parent core and an organic electroluminescent device comprising the same. The structure of the organic compound is shown in Formula 1. The compound with a specific structure of the present invention 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.

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 both new display and lighting products, potentially replacing existing liquid crystal displays and fluorescent lighting, and boasts a broad range of applications. OLED light-emitting devices resemble a sandwich structure, consisting of electrode material layers and organic functional materials sandwiched between these layers. These various functional materials are stacked together according to their intended use to form an OLED light-emitting device. As current devices, when a voltage is applied to the electrodes at both ends, the positive and negative charges in the organic functional material layers recombine in the light-emitting layer under the action of the electric field, generating OLED electroluminescence.

[0003] OLED optoelectronic functional materials used in OLED devices can be divided into two major categories based on their application: charge injection and transport materials and luminescent materials. Charge injection and transport materials can be further divided into electron injection and transport materials, electron blocking materials, hole injection and transport materials, and hole blocking materials. Charge transport materials are required to possess excellent carrier mobility and a high glass transition temperature. In OLED devices, electrons are injected from the cathode and then transferred through the electron transport layer to the host material, where they recombine with holes to generate excitons. Therefore, improving the injection and transport capabilities of the electron transport layer can help reduce the device's driving voltage while achieving high electron-hole recombination efficiency.

[0004] OLEDs have developed a variety of structures, including tandem OLEDs, which utilize multiple light-reflecting layers stacked on top of each other. Tandem OLEDs have a structure where a stack of layers, each consisting of a hole injection layer (HIL), a hole transport layer (HTL), an emissive layer, an electron transport layer (ETL), and an electron injection layer (EIL), is stacked between an anode and a cathode. Specifically, a charge generation layer (CGL), consisting of a NCGL and a PCGL, is placed between the layers to generate or inject charges into the emissive layer.

[0005] However, in CGLs, the ability to inject electrons generated at the interface between the PCGL and the adjacent hole injection layer (HIL) via charge generation into the NCGL is insufficient due to the energy level difference between the NCGL and PCGL. Furthermore, when conventional NCGLs are doped with alkali metals, the alkali metals diffuse into the PCGL, reducing the OLED lifetime.

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

[0007] To address the shortcomings of the prior art, the present invention provides an organic compound whose core contains a nitrogen-containing heterocyclic structure and an organic electroluminescent device containing the same. The compound of the present invention, with its specific structure, can provide a novel NCGL, thereby reducing the driving voltage of OLEDs, improving their luminous efficiency, and extending their lifespan.

[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 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 a 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 “substituted” refers to mono- or poly-substitution, and the substituents are 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 is 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 added to a mixed solution of toluene, ethanol, and water, followed by venting three 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 filtered through diatomaceous earth to remove salts 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 over anhydrous magnesium sulfate, and the solvent was removed using a rotary evaporator to obtain intermediate 1.

[0049] Under nitrogen protection, intermediate 1 (1.0 eq) and raw material C (1.0-1.1 eq) were stirred evenly in 280 mL of a mixed solvent of toluene, ethanol and water (volume ratio of 2:1:1), and then 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 the mixture was filtered using diatomaceous earth to remove salts and catalysts. After the filtrate was cooled to room temperature, it was washed with water three times, and the organic phase was retained. The aqueous phase was then extracted with ethyl acetate. After the organic phases were combined, they were dried using anhydrous magnesium sulfate, and the solvent was removed using a rotary evaporator to obtain the compound represented by general formula 1.

[0050] In another aspect, the present invention provides an organic electroluminescent device comprising an anode, 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 includes a charge generation layer, and the material of the charge generation layer includes the organic compound 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 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 compounds provided by the present invention have efficient charge generation capability and efficient electron transport performance, and can effectively improve the luminous efficiency of organic electroluminescent devices, while reducing the device driving voltage and extending the service life of organic electroluminescent devices.

[0056] The compounds of the present invention can effectively inhibit the film crystallinity of molecules, improve the film stability and heat resistance of the material, and thus improve the efficiency and life of the device. Furthermore, due to the good electron-withdrawing ability, film stability, and electron tolerance of the compounds of the present invention, when used as n-type materials for the CGL layer, they can form stable N-metal coordination bonds with metals such as Li or Yb, forming a stable and flat organic-metal doped film, which inhibits metal oxidation and helps improve 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 driving voltage of the device can be effectively reduced, and the luminous efficiency and life of the device 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 way of specific embodiments. It should be understood by those skilled in the art that the embodiments are merely 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 added to a mixed solution of toluene, ethanol, and water (volume ratio = 2:1:1), followed by venting three times. Potassium carbonate (2.0 eq) and tetrakis(triphenylphosphine)palladium (0.01 eq) were added under nitrogen protection, stirred evenly, heated to 90°C, and refluxed for 8 hours. After the reaction was completed, the temperature was slightly lowered and filtered using diatomaceous earth to remove salts and catalysts. 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 over anhydrous magnesium sulfate, and the solvent was removed using 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 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 the mixture was filtered using diatomaceous earth to remove salts and catalysts. 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 then extracted with ethyl acetate. After the organic phases were combined, they were dried over anhydrous magnesium sulfate, and the solvent was removed using 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] Analytical values: 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 added to a mixed solution of toluene, ethanol, and water (volume ratio = 2:1:1), followed by venting three times. Potassium carbonate (2.0 eq) and tetrakis(triphenylphosphine)palladium (0.01 eq) were added under nitrogen protection, stirred evenly, heated to 90°C, and refluxed for 8 hours. After the reaction was completed, the temperature was slightly lowered and filtered using diatomaceous earth to remove salts and catalysts. 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 over anhydrous magnesium sulfate, and the solvent was removed using 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 the reaction was stirred for 10 hours. After the reaction was completed, the temperature was slightly lowered, and the mixture was filtered using diatomaceous earth to remove salts and catalysts. 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 then extracted with ethyl acetate. After the organic phases were combined, they were dried over anhydrous magnesium sulfate, and the solvent was removed using 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] Analytical values: 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: A 150nm thick ITO (indium tin oxide)-Ag-ITO (indium tin oxide) glass substrate was cleaned twice in distilled water, ultrasonically cleaned for 30 minutes, then rinsed twice in distilled water, ultrasonically cleaned for 10 minutes, and then baked in a vacuum oven at 220°C for 2 hours. After baking, the substrate was cooled and ready for use. This substrate served as the anode and was deposited using an evaporation device. Other functional layers were then deposited on top.

[0084] First hole injection layer: On the washed anode layer, HT-1 and P-1 were deposited with a thickness of 10 nm using a vacuum evaporation device. 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 evaporated to a thickness of 24 nm as the first hole transport layer.

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

[0087] First light-emitting layer: After the above-mentioned first electron blocking material is evaporated, the light-emitting layer of the OLED light-emitting device is prepared. Its 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 light-emitting layer film thickness 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, with the mass ratio of ETM-1:Liq being 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 deposited by vacuum evaporation equipment, 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. The mass ratio of HT-1 to P-1 was 95:5 as the P-CGL layer.

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

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

[0094] Second light-emitting layer: After the above-mentioned 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, 5 nm of HB-1 was vacuum evaporated. This layer served as 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 with an ETM-1:Liq mass ratio of 1:1 as the second electron transport layer.

[0097] Second electron injection layer: On the second electron transport layer, YB with a thickness of 1 nm was formed 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 65nm was vacuum-deposited on the cathode as a light extraction layer;

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

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

[0102]

[0103] Device Application Examples 2-52: Referring to the above method, the compound 1 used in the device application example 1 was 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 corresponding organic electroluminescent devices.

[0104] Comparative Example: This comparative example provides an organic electroluminescent device. The only difference between the preparation method of this organic electroluminescent device and that of Device Example 1 is that the organic electroluminescent device is prepared by evaporating existing comparative compounds a and b instead of compound 1 in the NCGL layer of Device Example 1. The chemical structures of comparative compounds a and b are as follows:

[0105] .

[0106] The driving voltage, luminous efficiency and lifespan of the organic electroluminescent devices obtained from the device examples 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 stacked devices, the compounds provided by the present invention, with nitrogen-containing heterocycles as their core structure, exhibit efficient charge generation and electron transport properties, effectively improving the luminous efficiency of organic electroluminescent devices while reducing device driving voltage and extending their service life. When used as NCGL materials, compared with comparative compounds, device voltage decreased, while device efficiency and life were improved, further demonstrating the excellent technical performance of the compounds of the present invention when used as NCGL materials in stacked OLED devices.

[0111] The applicant states that while the present invention illustrates the organic compounds and organic electroluminescent devices thereof through the aforementioned embodiments, the present invention is not limited to these embodiments, nor does it necessarily rely on these embodiments for implementation. Persons skilled in the art will appreciate that any improvements to the present invention, equivalent substitutions for the raw materials used, additions of auxiliary components, and selection of specific methods, etc., fall within the scope of protection and disclosure of the present invention.

Claims

1. An organic compound, characterized in that The organic compound is any one of the following compounds:

2. An organic electroluminescent device, characterized in that: The organic electroluminescent device comprises an anode, 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 claim 1 .

3. The organic electroluminescent device according to claim 2, characterized in that: The organic thin film layer includes a charge generation layer, the charge generation layer includes an N-type charge generation layer and a P-type charge generation layer, and a material of the N-type charge generation layer includes the organic compound according to claim 1 .

4. The organic electroluminescent device according to claim 2, characterized in that: The organic thin film layer further includes any one or a combination of at least two 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.

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