Organic electroluminescent compound containing phenanthroline structure, preparation method and organic electroluminescent device

Abstract

The invention relates to the technical field of semiconductor materials, and discloses an organic electroluminescent compound containing a phenanthroline structure, a preparation method and an organic electroluminescent device. The organic electroluminescent compound containing the phenanthroline structure is a novel NCGL material, the compound contains the substituted phenanthroline structure, so that the compound has appropriate LUMO and HOMO energy levels, when the compound is applied to an OLED device, the driving voltage of the device is obviously reduced, the light emitting efficiency of the OLED is improved, the light emitting efficiency of the OLED is improved, and the light emitting efficiency of the OLED is improved. And the service life of the OLED device is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor materials, and particularly to an organic electroluminescent compound containing a phenanthroline structure, a preparation method thereof, and an organic electroluminescent device. Background Art

[0002] The technology of organic electroluminescent (OLED: Organic Light Emission Diodes) devices can be used to manufacture new display products and new lighting products, and is expected to replace existing liquid crystal displays and fluorescent lamp lighting, with a very broad application prospect. The OLED light-emitting device has a sandwich structure, including electrode material layers and organic functional materials sandwiched between different electrode material layers. Various different functional materials are stacked together according to their uses to jointly form the OLED light-emitting device. As a current device, when a voltage is applied to the two electrodes of the OLED light-emitting device and positive and negative charges in the organic layer functional material layer act through an electric field, the positive and negative charges further recombine in the light-emitting layer, that is, OLED electroluminescence is generated.

[0003] In a stacked OLED, the stacked OLED is formed by connecting two or more independent light-emitting units in series through a charge generation layer (CGL). Under the action of an external electric field, the electrons and holes generated by the CGL are respectively injected into adjacent light-emitting units and recombine into excitons to emit light in the light-emitting units. Therefore, the material selection and design of the CGL are the key factors affecting the photoelectric performance and lifespan of the stacked OLED. The CGL layer is constructed in a P-N structure form, where the P-type material mainly generates holes, such as materials like F4-TCNQ and HAT-CN, while the N-type doped material is doped with a low work function metal through an electron transport layer material, such as Alq 3: Mg and Bphen: Li, etc. Therefore, the performance of the electron transport material of the N-type doping material in CGL has a very great impact on the device performance, and it is required to have efficient electron injection ability, transport ability and high electron durability. At the same time, the heat resistance and film stability of the material are also important. Materials with low heat resistance are not only prone to decomposition during material evaporation, but also thermal decomposition will occur due to the heat generated by the device during device operation, resulting in material degradation. When the phase stability of the material film is poor, the material crystallizes in a short time, resulting in direct layer separation of the organic film layer and device degradation. Therefore, the materials used are required to have high heat resistance and good film stability. Multiple structures have been developed for OLED devices. Among them, a tandem-type OLED with multiple reflective layers stacked has been developed. The tandem-type OLED has the following structure: a stack 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 provided between the stacks to generate charges or inject charges into the light-emitting layer.

[0004] However, in CGL, due to the energy level difference between NCGL and PCGL, the electrons generated by charge generation at the interface between PCGL and the adjacent hole injection layer and injected into NCGL are insufficient. In addition, when conventional NCGL is doped with alkali metals, the alkali metals will diffuse into PCGL, resulting in a reduction in the life of the OLED.

[0005] In view of this, the present invention is specifically proposed. Summary of the Invention

[0006] In view of this, aiming at the deficiencies of the prior art, the present invention discloses and provides an organic electroluminescent compound containing a phenanthroline structure, a preparation method and an organic electroluminescent device.

[0007] It should be noted that the present invention provides an organic electroluminescent compound containing a phenanthroline structure, a novel NCGL material. The compound contains a substituted phenanthroline structure, making the compound have appropriate LUMO and HOMO energy levels. When applied to OLED devices, the driving voltage of the devices is significantly reduced, which not only improves the luminous efficiency of OLEDs but also extends the life of OLED devices.

[0008] In order to achieve the above object, the first object of the present invention is to provide an organic electroluminescent compound containing a phenanthroline structure, and the following technical scheme is adopted:

[0009] An organic electroluminescent compound containing a phenanthroline structure, and the structure of the organic electroluminescent compound is shown in General Formula 1:

[0010]

[0011] In the formula,

[0012] Ring A, ring B, and ring C are the same as or different from each other and are selected from substituted or unsubstituted C6-C24 aryl groups and substituted or unsubstituted C6-C24 heteroaryl groups;

[0013] At least one of ring A, ring B, and ring C is an N-containing group;

[0014] Ring A, ring C, and ring B are fused or substituted;

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

[0016] Ar is selected from H, D, substituted or unsubstituted C1-C20 alkyl groups, substituted or unsubstituted C3-C20 cycloalkyl groups, substituted or unsubstituted C6-C24 aryl groups, and substituted or unsubstituted C6-C24 heteroaryl groups, wherein the heteroatom is selected from O, N, and S..

[0017] Furthermore, L is selected from substituted or unsubstituted phenyl groups, biphenyl groups, terphenyl groups, and naphthyl groups;

[0018] Ar is selected from H, D, phenyl groups, biphenyl groups, terphenyl groups, naphthyl groups, pyridyl groups, methyl groups, ethyl groups, propyl groups, isopropyl groups, butyl groups, n-butyl groups, and tert-butyl groups;

[0019] Ring A, ring B, and ring C are each independently selected from phenyl groups, pyridyl groups, pyrimidinyl groups, triazinyl groups, carbazolyl groups, and furyl groups.

[0020] Furthermore, after ring A, B, and C are fused or substituted, they are selected from the following structures:

[0021]

[0022] Wherein,

[0023] Each X is independently selected from N or CR, and R is selected from H, D, phenyl groups, biphenyl groups, terphenyl groups, naphthyl groups, and pyridyl groups; after ring A, B, and C are fused or substituted, they contain at least one N atom;

[0024] Ring D is fused to the adjacent benzene ring, and ring D is selected from C6-C24 aryl groups;

[0025] * represents the connection position with L;

[0026] All hydrogens in the formula are unsubstituted by deuterium, partially substituted by deuterium, or fully substituted by deuterium.

[0027] The above "substitution" is mono-substitution or multi-substitution, and is selected from D, T, C 1 -C 10 alkyl, substituted or unsubstituted C 6 -C 24 aryl, substituted or unsubstituted C 6 -C 24 heteroaryl, wherein the heteroatom is selected from O, N, S.

[0028] In the above technical solution, the organic electroluminescent compound is any one of the following structures, but not limited thereto:

[0029]

[0030]

[0031]

[0032]

[0033]

[0034]

[0035]

[0036]

[0037]

[0038] It should be noted that the group definitions corresponding to the general formula 1 compound in the above example compounds and the example compounds in the specific embodiments are also covered within the preferred definition ranges of each group. Any combination or combination of these specific group definitions and the group definitions in the general formula 1 are also covered within the technical solutions described in this specification.

[0039] The second technical object of the present invention is to provide a preparation method of the above-mentioned organic electroluminescent compound containing a phenanthroline structure, and the method specifically includes the following steps:

[0040]

[0041] The above L, Ar, ring A, ring B, ring C are defined as described above, Hal 1 and Hal 2 are selected from halogen atoms.

[0042] The specific operation is as follows:

[0043] Under nitrogen protection, raw material A (1.0 - 1.1 eq) and raw material B (1.0 eq) were added into a mixed solution of toluene, ethanol, and water with a volume ratio of 2:1:1. Then, the gas was exchanged three times. Under nitrogen protection, potassium carbonate (2.0 eq) and tetrakis(triphenylphosphine)palladium (0.01 eq) were added. After stirring evenly, the temperature was raised to 90 - 100 °C, and the mixture was refluxed for 8 - 10 h. After the reaction ended, the temperature was lowered, and filtration was carried out using diatomaceous earth to remove salts and catalysts. After the filtrate was cooled to room temperature, it was washed three times with water, and the organic phase was retained. Then, the aqueous phase was extracted with ethyl acetate. After combining the organic phases, drying was carried out using anhydrous magnesium sulfate, and the solvent was removed using a rotary evaporator to obtain intermediate 1.

[0044] Under nitrogen protection, intermediate 1 (1.0 eq) and raw material C (1.0 - 1.1 eq) were stirred evenly in a mixed solvent of 280 mL of toluene, ethanol, and water (volume ratio 2:1:1), and then 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 - 100 °C and stirred for 8 - 10 h. After the reaction ended, the temperature was lowered, and filtration was carried out using diatomaceous earth to remove salts and catalysts. After the filtrate was cooled to room temperature, it was washed three times with water, and the organic phase was retained. Then, the aqueous phase was extracted with ethyl acetate. After combining the organic phases, drying was carried out using anhydrous magnesium sulfate, and the solvent was removed using a rotary evaporator to obtain the compound shown in General Formula 1.

[0045] The third object of the present invention is to provide an organic electroluminescent device, and the organic electroluminescent device includes the organic electroluminescent compound containing a phenanthroline structure as described above.

[0046] Specifically, the organic electroluminescent device includes a first electrode, a second electrode, and at least one organic thin film layer disposed between the first electrode and the second electrode; the organic thin film layer contains the organic electroluminescent compound containing a phenanthroline structure as described above.

[0047] Moreover, the organic electroluminescent compound containing a phenanthroline structure is used as a material for the N-type charge generation layer (NCGL layer) of the organic electroluminescent device.

[0048] Compared with the prior art, the present invention provides an organic electroluminescent compound containing a phenanthroline structure, a preparation method, and an organic electroluminescent device, which have the following excellent effects:

[0049] 1) The organic electroluminescent compound provided by the present invention contains a substituted phenanthroline structure. The compound has high charge generation ability and high electron transport performance, can effectively improve the luminous efficiency of the organic electroluminescent device, reduce the driving voltage of the device, and extend the service life of the organic electroluminescent device.

[0050] 2) The compounds of the present invention can effectively inhibit the film crystallinity of molecules, improve the film stability and heat resistance durability of materials, which is beneficial to improving the device efficiency and lifespan.

[0051] 3) After the compounds of the present invention are applied as organic electroluminescent NCGL layer materials in OLED devices, they can effectively reduce the device driving voltage and improve the device luminescence efficiency and lifespan. Description of the Drawings

[0052] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on the provided drawings.

[0053] Figure 1 1H NMR spectrum of Compound 1 provided in Embodiment 1 of the present invention. Detailed Embodiments

[0054] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments of the present invention and the relevant drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0055] The present invention specifically discloses an organic electroluminescent compound containing a phenanthroline structure, a preparation method, and an organic electroluminescent device.

[0056] It should be noted that the values given in the following embodiments are as accurate as possible. However, those skilled in the art understand that due to inevitable measurement errors and experimental operation problems, each number should be understood as an approximate number rather than an absolutely accurate value.

[0057] The following further illustrates the technical solutions of the present invention through specific embodiments. Those skilled in the art should understand that the described embodiments are only for helping to understand the present invention and should not be regarded as specific limitations of the present invention.

[0058] Embodiment 1

[0059]

[0060] Under nitrogen protection, raw material A (1.0 eq) and raw material B (1.0 eq) were added into a mixed solution of toluene, ethanol, and water with a volume ratio of 2:1:1. Then, the gas was exchanged three times. Under nitrogen protection, potassium carbonate (2.0 eq) and tetrakis(triphenylphosphine)palladium (0.01 eq) were added. After stirring evenly, the temperature was raised to 90 °C, and the mixture was refluxed for 8 h. After the reaction was completed, the temperature was lowered, and filtration was carried out using diatomaceous earth to remove salts and the catalyst. After the filtrate was cooled to room temperature, it was washed with water three times, and the organic phase was retained. Then, the aqueous phase was extracted with ethyl acetate; after combining the organic phases, drying was carried out using anhydrous magnesium sulfate, and the solvent was removed using a rotary evaporator to obtain intermediate 1.

[0061] 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 of toluene, ethanol, and water (volume ratio 2:1:1), and then 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 100 °C and stirring was continued for 10 h. After the reaction was completed, the temperature was lowered, and filtration was carried out using diatomaceous earth to remove salts and the catalyst. After the filtrate was cooled to room temperature, it was washed with water three times, and the organic phase was retained. Then, the aqueous phase was extracted with ethyl acetate; after combining the organic phases, drying was carried out using anhydrous magnesium sulfate, and the solvent was removed using a rotary evaporator to obtain compound 1 with a yield of 57.3%.

[0062] The obtained compound 1 was detected and analyzed, and the results were as follows:

[0063] HPLC purity: >99.95%.

[0064] MS (ESI, m / z): [M + H]+: 423.16

[0065] Elemental analysis:

[0066] Calculated values: C, 82.44; H, 4.29; N, 13.26.

[0067] Measured values: C, 82.02; H, 4.55; N, 13.49.

[0068] Example 2

[0069]

[0070] Under nitrogen protection, raw material A (1.0 eq) and raw material B (1.0 eq) were added into a mixed solution of toluene, ethanol, and water with a volume ratio of 2:1:1. Then, the gas was exchanged three times. Under nitrogen protection, potassium carbonate (2.0 eq) and tetrakis(triphenylphosphine)palladium (0.01 eq) were added. After stirring evenly, the temperature was raised to 90 °C, and the mixture was refluxed for 8 h. After the reaction ended, the temperature was lowered, and filtration was carried out using diatomaceous earth to remove salts and catalysts. After the filtrate was cooled to room temperature, it was washed three times with water, and the organic phase was retained. Then, the aqueous phase was extracted with ethyl acetate; after combining the organic phases, drying was carried out using anhydrous magnesium sulfate, and the solvent was removed using a rotary evaporator to obtain intermediate 1.

[0071] 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 of toluene, ethanol, and water (volume ratio 2:1:1), and then 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 100 °C and stirring was continued for 10 h. After the reaction ended, the temperature was lowered, and filtration was carried out using diatomaceous earth to remove salts and catalysts. After the filtrate was cooled to room temperature, it was washed three times with water, and the organic phase was retained. Then, the aqueous phase was extracted with ethyl acetate; after combining the organic phases, drying was carried out using anhydrous magnesium sulfate, and the solvent was removed using a rotary evaporator to obtain compound 73, yield: 58.2%.

[0072] The obtained compound 73 was detected and analyzed, and the results were as follows:

[0073] HPLC purity: >99.95%.

[0074] MS (ESI, m / Z): [M + H]+: 435.16

[0075] Elemental analysis:

[0076] Calculated values: C, 82.93; H, 4.18; N, 12.89.

[0077] Measured values: C, 82.69; H, 4.37; N, 13.21.

[0078] Device application example 1: Preparation of organic electroluminescent device

[0079] Anode: ITO Anode: Wash the ITO (Indium Tin Oxide)-Ag-ITO (Indium Tin Oxide) glass substrate with a coating thickness of 150 nm twice in distilled water, ultrasonically wash for 30 min, then wash repeatedly twice with distilled water and ultrasonically wash for 10 min. After the washing is completed, bake in a vacuum oven at 220 °C for 2 hours, and it can be used after cooling. Using this substrate as the anode, perform the evaporation device process with an evaporation coater, and sequentially evaporate other functional layers on it;

[0080] First Hole Injection Layer: On the anode layer after the above washing, use a vacuum evaporation device to evaporate HT-1 and P-1 with a film thickness of 10 nm, and the mass ratio of HT-1 and P-1 is 97:3 as the first hole injection layer;

[0081] First Hole Transport Layer: Evaporate HT-1 with a thickness of 24 nm on the above first hole injection layer as the first hole transport layer;

[0082] First Electron Blocking Layer: Evaporate EB-1 with a thickness of 5 nm on the above first hole transport layer as the first electron blocking layer;

[0083] First Light Emitting Layer: After the evaporation of the first electron blocking layer material is completed, fabricate the light emitting layer of the OLED device, where BH-1 is used as the host material and BD-1 is used as the doping material, and the doping ratio of the doping material is 3% (weight ratio), and the film thickness of the light emitting layer is 20 nm;

[0084] First Hole Blocking Layer: Evaporate HB-1 with a thickness of 5 nm on the above first light emitting layer as the first hole blocking layer;

[0085] First Electron Transport Layer: Evaporate ETM-1 and Liq with a thickness of 10 nm on the above first hole blocking layer, and the mass ratio of ETM-1 and Liq is 1:1 as the first electron transport layer;

[0086] NCGL Layer: Evaporate Compound 1 and Yb with a thickness of 20 nm on the above first electron transport layer, and the mass ratio of Compound 1 and Yb is 95:5 as the N-type Charge Generation Layer (NCGL layer);

[0087] PCGL Layer: Evaporate a co-evaporation layer of HT-1 and P-1 with a film thickness of 10 nm on the above NCGL layer, and the mass ratio of HT-1 and P-1 is 95:5 as the PCGL layer;

[0088] Second Hole Transport Layer: Evaporate HT-1 with a film thickness of 30 nm on the above PCGL layer as the second hole transport layer;

[0089] Second Electron Blocking Layer: Evaporate EB-1 with a thickness of 5 nm on the above second hole transport layer as the second electron blocking layer;

[0090] Second light-emitting layer: After the evaporation of the above-mentioned second electron blocking layer material is completed, the second light-emitting layer of the OLED light-emitting device is fabricated. Among them, BH-1 is used as the host material, BD-1 is used as the doping material, the doping ratio of the doping material is 3% (weight ratio), and the film thickness of the light-emitting layer is 20 nm;

[0091] Second hole blocking layer: HB-1 with a thickness of 5 nm is evaporated on the above-mentioned second light-emitting layer as the second hole blocking layer;

[0092] Second electron transport layer: ETM-1 and Liq with a thickness of 15 nm are evaporated on the above-mentioned second hole blocking layer, and the mass ratio of ETM-1 to Liq is 1:1, serving as the second electron transport layer;

[0093] Second electron injection layer: YB with a thickness of 1 nm is evaporated on the above-mentioned second electron transport layer as the second electron injection layer;

[0094] Cathode: An electrode layer of Mg and Ag with a thickness of 13 nm is evaporated on the above-mentioned second electron injection layer, and the mass ratio of Mg to Ag is 1:9, which is the cathode layer;

[0095] Light extraction layer: CPL-1 with a thickness of 65 nm is vacuum-evaporated on the cathode as the light extraction layer;

[0096] The evaporated substrate is encapsulated: First, the cleaned cover plate is coated with UV glue using a glue coating device, then the coated cover plate is moved to the pressing section, the evaporated substrate is placed on the upper end of the cover plate, and finally the substrate and the cover plate are bonded under the action of a bonding device, while the UV glue is cured by light irradiation.

[0097] The structural formulas of the materials used are as follows:

[0098]

[0099] Device application examples 2 - 40:

[0100] Referring to the above method, Compound 1 used in Device Application Example 1 was replaced with Compound 73, Compound 2, Compound 4, Compound 6, Compound 7, Compound 9, Compound 11, Compound 14, Compound 16, Compound 21, Compound 25, Compound 27, Compound 31, Compound 36, Compound 42, Compound 47, Compound 50, Compound 52, Compound 59, Compound 62, Compound 68, Compound 72, Compound 76, Compound 80, Compound 82, Compound 88, Compound 95, Compound 97, Compound 102, Compound 104, Compound 113, Compound 116, Compound 123, Compound 127, Compound 130, Compound 132, Compound 136, Compound 138, Compound 140 as the compound in the NCGL layer, and the corresponding organic electroluminescent devices were prepared.

[0101] Device Comparative Example:

[0102] 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 in this organic electroluminescent device, the existing comparative compounds a and b were used to replace Compound 1 used in the NCGL layer of the above Device Example 1 for evaporation coating to prepare Device Comparative Examples 1-2.

[0103] Among them, the chemical structural formulas of comparative compounds a and b are:

[0104]

[0105] The driving voltage, luminous efficiency, and lifetime of the organic electroluminescent devices obtained in the above Device Examples 2-40 and Device Comparative Examples 1-2 were characterized at a brightness of 1000 (nits), and the test results are shown in Table 1 below:

[0106] Table 1:

[0107]

[0108]

[0109] Note: In a blue top-emitting device, the current efficiency is greatly affected by chromaticity. Therefore, considering the influence factor of chromaticity on efficiency, the ratio of luminous efficiency to CIEy is defined as the BI value, that is, BI = (cd / A) / CIEy.

[0110] As can be seen from Table 1, in a stacked device, the compound provided by the present invention has a structure of substituted phenanthroline, has high charge generation ability and high electron transport performance, can effectively improve the luminous efficiency of the organic electroluminescent device, reduce the device driving voltage, and extend the service life of the organic electroluminescent device.

[0111] When the compound of the present invention is used as an NCGL material, compared with the comparative compound, the device voltage decreases, and the device efficiency and device life are improved. This further shows that the compound of the present invention has good technical effects when used as an NCGL material in a stacked OLED device.

[0112] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather to the broadest scope consistent with the principles and novel features disclosed herein.

Claims

1. An organic electroluminescent compound containing a phenanthroline structure, characterized in that: The structure of the organic electroluminescent compound containing a phenanthroline structure is shown in Formula 1: In the formula, Ring A, Ring B, and Ring C are the same as or different from each other and are selected from substituted or unsubstituted C6-C24 aryl groups, substituted or unsubstituted C6-C24 heteroaryl groups; At least one of ring A, ring B, and ring C is a N-containing group; Ring A, Ring C and Ring B are fused or substituted; L is selected from substituted or unsubstituted C6-C24 aryl, substituted or unsubstituted C6-C24 heteroaryl, wherein the heteroatom is selected from O, N, S; Ar is selected from H, D, substituted or unsubstituted C1-C20 alkyl, substituted or unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted C6-C24 aryl, substituted or unsubstituted C6-C24 heteroaryl, wherein the heteroatom is selected from O, N, S.

2. The organic electroluminescent compound containing a phenanthroline structure according to claim 1, characterized in that: L is selected from substituted or unsubstituted phenyl, biphenyl, terphenyl, naphthyl; Ar is selected from H, D, phenyl, biphenyl, terphenyl, naphthyl, pyridyl, methyl, ethyl, propyl, isopropyl, butyl, n-butyl, tert-butyl; Ring A, Ring B and Ring C are each independently selected from phenyl, pyridyl, pyrimidinyl, triazine, carbazolyl and furyl.

3. The organic electroluminescent compound containing a phenanthroline structure according to claim 1, characterized in that: After the A, B, and C rings are fused or substituted, they are selected from the following structures: in, Each X is independently selected from N or CR, R is selected from H, D, phenyl, biphenyl, terphenyl, naphthyl, pyridyl; Ring A, Ring B, Ring C contain at least one N atom after fusion or substitution; Ring D is fused to an adjacent benzene ring, and ring D is selected from a C6-C24 aryl group; * indicates the connection position with L; In the formula, all hydrogens are not substituted with deuterium, partially substituted with deuterium, or all substituted with deuterium.

4. The organic electroluminescent compound containing a phenanthroline structure according to any one of claims 1 to 3, characterized in that: "Substitution" is mono- or poly-substituted, selected from D, T, C1-C 10 Alkyl, substituted or unsubstituted C6-C 24 Aryl, substituted or unsubstituted C6-C 24 Heteroaryl, wherein the heteroatom is selected from O, N, S.

5. The organic electroluminescent compound containing a phenanthroline structure according to claim 1, characterized in that: The structure of the organic electroluminescent compound containing a phenanthroline structure includes but is not limited to any one of the following compounds:

6. A method for preparing an organic electroluminescent compound containing a phenanthroline structure as claimed in claim 1, characterized in that: The method operates as follows: Under nitrogen protection, raw material A (1.0-1.1 eq) and raw material B (1.0 eq) were put into a mixed solution of toluene, ethanol and water in a volume ratio of 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 90-100° C., and reflux reaction for 8-10 hours; after the reaction was completed, cooling, filtering with diatomaceous earth to remove salt and catalyst, cooling the filtrate to room temperature, washing with water three times, retaining the organic phase, and then extracting the aqueous phase with ethyl acetate; after combining the organic phases, drying with anhydrous magnesium sulfate, and removing the solvent with a rotary evaporator to obtain intermediate 1; 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), palladium acetate (Pd(OAc)2) (0.05 eq), and cesium carbonate (2.0 eq) were added. After sufficient stirring, the temperature was raised to 90-100° C. and stirred for 8-10 hours. After the reaction was completed, the temperature was 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; The specific synthetic route is as follows: In the above formula, L, Ar, ring A, ring B, and ring C are as defined in the above general formula 1, and Hal1 and Hal2 are selected from halogen atoms.

7. An organic electroluminescent device, characterized in that: The organic electroluminescent device comprises the organic electroluminescent compound containing a phenanthroline structure as claimed in claim 1.

8. The organic electroluminescent device according to claim 7, characterized in that: The organic electroluminescent device comprises a first electrode, a second electrode and at least one organic thin film layer arranged between the first electrode and the second electrode; the organic thin film layer comprises the organic electroluminescent compound containing a phenanthroline structure.

9. The organic electroluminescent device according to claim 8, characterized in that: The organic electroluminescent compound containing a phenanthroline structure is used as an N-type charge generation layer material of an organic electroluminescent device.

Images