Nitrogen-containing heterocyclic ring compound and organic electroluminescent device comprising same

Abstract

The invention discloses a compound containing a nitrogen heterocyclic ring structure and an organic electroluminescent device containing the compound, and belongs to the technical field of semiconductor materials. The structure of the compound is shown in the general formula (1), the compound has good stability and electron endurance capacity and also has good electron injection and electron transmission capacity, and when the compound is used as an electron transmission material of an organic electroluminescent device, the driving voltage of the device is remarkably reduced, and the driving efficiency of the device is improved. And the service life of the device is obviously improved.

Description

Technical Field

[0001] This invention relates to the field of semiconductor materials technology, and in particular to a nitrogen-containing heterocyclic compound and an organic electroluminescent device containing the same. Background Technology

[0002] Organic light-emitting diodes (OLEDs) technology can be used to manufacture novel display products and lighting products, and is expected to replace existing liquid crystal displays and fluorescent lighting, with a very wide range of applications. OLEDs have a sandwich-like structure, including electrode material layers and organic functional materials sandwiched between different electrode material layers. Various organic functional materials are stacked together according to their intended use to form the OLED. As a current-emitting device, when a voltage is applied to its two electrodes, and an electric field is applied to the positive and negative charges in the organic functional material layers, the positive and negative charges recombine in the light-emitting layer, thus generating organic electroluminescence.

[0003] Currently, OLED display technology has been applied in smartphones, tablets, televisions, and other fields. However, compared with the requirements of actual product applications, the luminous efficiency and lifespan of organic electroluminescent devices still need further improvement. In order to continuously improve the performance of organic electroluminescent devices, it is necessary to continuously research and innovate organic optoelectronic functional materials to create higher-performance organic optoelectronic functional materials.

[0004] Organic optoelectronic functional materials used in organic electroluminescent devices can be broadly classified into two categories based on their applications: charge injection transport materials and luminescent materials. Further, charge injection transport materials can be categorized into electron injection transport materials, electron blocking materials, hole injection transport materials, and hole blocking materials. As charge transport materials, they require good carrier mobility and high glass transition temperature. In organic electroluminescent devices, electrons are injected from the cathode and then transported 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 helps reduce the device driving voltage while achieving high electron-hole recombination efficiency. Thus, the electron transport layer is crucial, requiring high electron injection and transport capabilities as well as high electron durability.

[0005] For device lifespan, the heat resistance and film stability of materials are also crucial. Materials with low heat resistance are prone to decomposition not only during material vapor deposition but also during device operation due to the heat generated, leading to material degradation. In cases of poor film phase stability, the material may also undergo rapid film crystallization, causing delamination of the organic film layer and resulting in device degradation. Therefore, materials with high heat resistance and good film stability are required.

[0006] With the increasing demand for improved performance in organic electroluminescent devices, the requirements for material properties are also rising. These materials need not only good stability but also high efficiency and lifespan at low driving voltages. However, current electron transport materials suffer from insufficient thermal stability and deficiencies in electron tolerance, leading to phase separation or decomposition during device operation and consequently, shorter device lifespans. Summary of the Invention

[0007] To address the aforementioned problems in the prior art, this invention provides a nitrogen-containing heterocyclic compound and an organic electroluminescent device containing the same. The compound of this invention has excellent electron injection and transport capabilities, and when applied to organic electroluminescent devices, it can effectively reduce the device operating voltage and extend the device's operating life.

[0008] The present invention provides the following technical solution: a compound containing a nitrogen heterocyclic structure, the structure of which is shown in general formula (1):

[0009]

[0010] In general formula (1), X1 to X3 are each independently represented as nitrogen atom or CH, and at least one of them is represented as nitrogen atom; X4 to X6 are each independently represented as nitrogen atom or CH, and at least one of them is represented as nitrogen atom;

[0011] Among them, X1 to X6 can be represented by a maximum of five nitrogen atoms;

[0012] R1 and R3 are each independently represented as hydrogen atoms, and R... a Substituted or unsubstituted phenyl, by R a Substituted or unsubstituted naphthyl groups, derived from R a Substituted or unsubstituted diphenyl, derived from R a Substituted or unsubstituted dibenzofuranyl;

[0013] R2 represents a hydrogen atom, a phenyl group, and R... a Substituted or unsubstituted naphthyl groups, derived from R a Substituted or unsubstituted diphenyl, derived from R a Substituted or unsubstituted dibenzofuranyl;

[0014] Among R1, R2, and R3, there is exactly one that is not represented as a hydrogen atom;

[0015] Ar1 and Ar2 can be the same or different, and each can be independently represented by R. b Substituted or unsubstituted phenyl, by R b Substituted or unsubstituted naphthyl groups, derived from R b Substituted or unsubstituted diphenyl, derived from R b Substituted or unsubstituted triphenyl, by R b Substituted or unsubstituted pyridinyl groups, derived from R b Substituted or unsubstituted pyrimidine groups, derived from R b Substituted or unsubstituted dibenzofuranyl;

[0016] Ar3 and Ar4 can be the same or different, and each can be independently represented by R. c Substituted or unsubstituted phenyl, by R c Substituted or unsubstituted naphthyl groups, derived from R c Substituted or unsubstituted diphenyl, derived from R c Substituted or unsubstituted triphenyl, by R c Substituted or unsubstituted pyridinyl groups, derived from R c Substituted or unsubstituted pyrimidine groups, derived from R c Substituted or unsubstituted dibenzofuranyl;

[0017] The R a Represented as cyano, phenyl, diphenyl, triphenyl, pyridyl, pyrimidinyl;

[0018] The R b Represented as phenyl, diphenyl, triphenyl, pyridyl, pyrimidinyl;

[0019] The R c Represented as cyano, phenyl, diphenyl, triphenyl, pyridyl, pyrimidinyl;

[0020] At least one of Ar3, Ar4, R1, R2, and R3 is substituted with a cyano group.

[0021] Furthermore, two or three of X1 to X3 are represented as nitrogen atoms.

[0022] Furthermore, two or three of X4 to X6 are represented as nitrogen atoms.

[0023] Furthermore, four or five of X1 to X6 are represented as nitrogen atoms.

[0024] Furthermore, the structure of the compound is shown in any one of general formulas (2-1) to (2-4):

[0025]

[0026] In general formulas (2-1) to (2-4), the meanings of Ar1, Ar2, Ar3, Ar4, R1, R2, R3, X1, X2, and X3 are the same as those in general formula (1) above.

[0027] Furthermore, the structure of the compound is shown in any one of general formulas (3-1) to (3-4):

[0028]

[0029] In general formulas (3-1) to (3-4), the meanings of Ar1, Ar2, Ar3, Ar4, R1, R2, R3, X4, X5, and X6 are the same as those in general formula (1) above.

[0030] Furthermore, the structure of the compound is shown in any one of general formulas (4-1) to (4-4):

[0031]

[0032] In general formulas (4-1) to (4-4), the meanings of Ar1, Ar2, Ar3, Ar4, R1, R2, and R3 are the same as those in general formula (1) above.

[0033] Furthermore, the structure of the compound is shown in any one of general formulas (5-1) to (5-4):

[0034]

[0035] In general formulas (5-1) to (5-4), the meanings of Ar1, Ar2, Ar3, Ar4, R1, R2, and R3 are the same as those in general formula (1) above.

[0036] Furthermore, the structure of the compound is shown in any one of general formulas (6-1) to (6-3):

[0037]

[0038] In general formulas (6-1) to (6-3), the meanings of Ar1, Ar2, Ar3, Ar4, R1, R2, and R3 are the same as those in general formula (1) above;

[0039] Each of X1 to X3 is independently represented as a nitrogen atom or CH, and two or three of them are represented as nitrogen atoms;

[0040] Each of X4 to X6 is independently represented as a nitrogen atom or CH, and two or three of them are represented as nitrogen atoms;

[0041] Four or five of X1 to X6 are represented by nitrogen atoms.

[0042] Furthermore, the specific structure of the compound is any one of the following structures:

[0043]

[0044]

[0045]

[0046]

[0047]

[0048]

[0049]

[0050]

[0051]

[0052]

[0053]

[0054]

[0055]

[0056]

[0057] The present invention also provides an organic electroluminescent device comprising a substrate, a first electrode and a second electrode, wherein a multilayer organic thin film layer is provided between the first electrode and the second electrode, and the organic thin film layer contains the compound with the nitrogen-containing heterocyclic structure.

[0058] Furthermore, the organic thin film layer includes a hole transport region thin film layer, a light emission region thin film layer, and an electron transport region thin film layer, wherein the electron transport region thin film layer contains the compound with the nitrogen-containing heterocyclic structure;

[0059] Preferably, the electron transport region thin film layer includes an electron transport layer containing the nitrogen-containing heterocyclic compound.

[0060] Furthermore, the hole transport region thin film layer includes a hole injection layer, a hole transport layer, and an electron blocking layer, and the electron transport region thin film layer includes a hole blocking layer, an electron transport layer, and an electron injection layer, and the electron transport layer contains the compound with the nitrogen-containing heterocyclic structure.

[0061] Technical effect

[0062] The nitrogen-containing heterocyclic compounds of this invention exhibit good electronic tolerance and stability, as well as excellent electron injection and transport capabilities. Therefore, when used as electron transport materials for OLED functional layers, they can effectively reduce device driving voltage and improve the photoelectric performance and device lifetime of organic electroluminescent devices.

[0063] Furthermore, under the influence of an electric field or heat, the compounds of this invention, due to their strong electron-withdrawing conjugation effect, readily reduce and ionize lithium ions in lithium complexes, thereby enhancing electron injection capability. Therefore, as electron transport materials, these compounds possess excellent electron transport capabilities and good electron injection properties, effectively reducing device drive voltage, improving device efficiency, and extending device lifespan. Attached Figure Description

[0064] Figure 1 This is a schematic diagram of the structure of an OLED device using the materials listed in this invention. In the figure, 1 is a transparent substrate layer, 2 is an anode layer, 3 is a hole injection layer, 4 is a hole transport layer, 5 is an electron blocking layer, 6 is a light-emitting layer, 7 is a hole blocking layer, 8 is an electron transport layer, 9 is an electron injection layer, 10 is a cathode layer, and 11 is a light extraction layer. Detailed Implementation

[0065] The technical solution of the present invention will be described in detail below with reference to the implementation scheme.

[0066] In this invention, unless otherwise stated, HOMO refers to the highest occupied orbital of a molecule, and LUMO refers to the lowest empty orbital of a molecule. Furthermore, in this invention, HOMO and LUMO energy levels are represented by absolute values, and comparisons between energy levels are made by comparing their absolute values. Those skilled in the art know that the larger the absolute value of an energy level, the lower its energy.

[0067] In the accompanying drawings, the dimensions of layers and regions may be exaggerated for clarity. It will also be understood that when a layer or element is referred to as being "above" another layer or substrate, the layer or element may be located directly above that other layer or substrate, or there may be intermediate layers. Furthermore, it will be understood that when a layer is referred to as being "between" two layers, the layer may be the only layer between the two layers, or there may be one or more intermediate layers.

[0068] In this invention, the terms "upper" and "lower," used to indicate orientation when describing electrodes, organic electroluminescent devices, and other structures, only indicate orientation in a specific state and do not imply that the related structures can only exist in the stated orientation. Conversely, if a structure can be repositioned, such as by inverting it, the orientation of the structure changes accordingly. Specifically, in this invention, the "lower" side of an electrode refers to the side of the electrode closer to the substrate during fabrication, while the opposite side farther from the substrate is the "upper" side.

[0069] Organic electroluminescent devices

[0070] The organic electroluminescent device of the present invention can be a bottom-emitting organic electroluminescent device, a top-emitting organic electroluminescent device, or a multilayer organic electroluminescent device, and there is no specific limitation thereto.

[0071] The organic electroluminescent device of the present invention includes a substrate, a first electrode, a multilayer organic thin film layer, and a second electrode. The multilayer organic thin film layer includes a hole transport region, a light-emitting layer, and an electron transport region. The hole transport region includes a hole injection layer, a hole transport layer, and an electron blocking layer. The electron transport region includes a hole blocking layer, an electron transport layer, and an electron injection layer. Additionally, a capping layer may be disposed on the second electrode.

[0072] The organic electroluminescent device of the present invention may include the following layers and their positional relationships: it may include a substrate, a first electrode, a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, a hole blocking layer, an electron transport layer, an electron injection layer, and a second electrode. If the above layers are present, the first electrode is on the substrate, the hole injection layer is on the first electrode, the hole transport layer is on the hole injection layer, the electron blocking layer is on the hole transport layer, the light-emitting layer is on the electron blocking layer, the hole blocking layer is on the light-emitting layer, the electron transport layer is on the hole blocking layer, the electron injection layer is on the electron transport layer, the second electrode is on the electron injection layer, and a capping layer is on the second electrode.

[0073] As the substrate for the organic electroluminescent device of this invention, any substrate commonly used in organic electroluminescent devices can be used. Examples include transparent substrates, such as glass or transparent plastic substrates; opaque substrates, such as silicon substrates; and flexible PI film substrates. Different substrates have different mechanical strengths, thermal stability, transparency, surface smoothness, and water resistance. Their application varies depending on their properties. In this invention, a transparent substrate is preferred, and the thickness of the substrate is not particularly limited.

[0074] A first electrode is formed on a substrate, and the first electrode and a second electrode may be opposite each other. The first electrode can be an anode or a cathode. In this invention, the first electrode serves as the anode, and the anode material is preferably a material with a high work function so that holes can be easily injected into the organic functional material layer. Non-limiting examples of anode materials include, but are not limited to, indium tin oxide (ITO), indium zinc oxide (IZO), tin oxide (SnO2), zinc oxide (ZnO), magnesium (Mg), aluminum (Al), silver (Ag), aluminum-lithium (Al-Li), calcium (Ca), magnesium-indium (Mg-In), and magnesium-silver (Mg-Ag). The first electrode may have a single-layer structure or a multilayer structure comprising two or more layers. In addition, the thickness of the anode depends on the material used, typically 50-500 nm, preferably 70-300 nm, and more preferably 100-200 nm.

[0075] The hole injection layer, hole transport layer, and electron blocking layer can be disposed between the first electrode and the light-emitting layer.

[0076] The hole injection layer may comprise a host material and a p-type doped material. The host material may be selected from conventional hole transport materials in the prior art, preferably the same organic material as the hole transport layer. The p-type doped material is selected from charge-conducting compounds disclosed in the prior art, and may be selected from compounds disclosed in the following patent documents: WO2011073149A, EP1968131A1, EP2276085A1, EP2213662A1, EP1722602A1, EP2 045848A1, DE102007031220A1, US20100181555A1, US20100102709A1, WO2009003455A1, WO2010094378A1, WO2011120709A1, US20100096600A1, DE102012209523A1, CN101728485A and WO2012095143A1, but not limited to these.

[0077] For example, the compounds shown below:

[0078]

[0079] According to the present invention, P1 is preferably used as the P-type doped material.

[0080] The thickness of the hole injection layer of the present invention can be 1-100 nm, preferably 2-50 nm, and more preferably 5-20 nm.

[0081] The material of the hole transport layer is preferably a material with high hole mobility, which enables holes to be transferred from the anode or hole injection layer to the light-emitting layer.

[0082] Preferably, the hole transport layer material of the present invention may be selected from the compounds disclosed in the prior art:

[0083]

[0084] The thickness of the hole transport layer of the present invention can be 5-200 nm, preferably 10-180 nm, and more preferably 20-150 nm.

[0085] The electron blocking layer requires that its triplet (T1) energy level be higher than that of the host material in the emissive layer, thus blocking energy loss from the emissive layer material. The HOMO energy level of the electron blocking layer material should be between that of the hole transport layer material and the host material of the emissive layer, facilitating hole injection from the positive electrode into the emissive layer. Simultaneously, the electron blocking layer material should possess high hole mobility to promote hole transport and reduce the power consumption of the device. The LUMO energy level of the electron blocking layer material should be higher than that of the host material of the emissive layer, serving as an electron blocker; that is, the electron blocking layer material should have a wide bandgap (Eg). Electron blocking layer materials meeting these conditions can be triarylamine derivatives, fluorene derivatives, spirofluorene derivatives, dibenzofuran derivatives, carbazole derivatives, etc.

[0086] In one embodiment of the present invention, the electron blocking layer material may be selected from the compounds disclosed in the prior art:

[0087]

[0088]

[0089] According to the present invention, the thickness of the electron blocking layer can be 1-200 nm, preferably 5-150 nm, and more preferably 5-50 nm.

[0090] According to the present invention, the light-emitting layer is located between the electron blocking layer and the hole blocking layer. The material of the light-emitting layer is a material that emits visible light by respectively receiving holes from the hole transport region and electrons from the electron transport region, and combining the received holes and electrons. The light-emitting layer may include a host material and a dopant material. As the host material and guest material of the light-emitting layer of the organic electroluminescent device of the present invention, the host material may be one or a combination of two of anthracene derivatives, quinoxaline derivatives, triazine derivatives, xanthanone derivatives, diphenyl ketone derivatives, carbazole derivatives, pyridine derivatives, or pyrimidine derivatives. The guest material may be a pyrene derivative, boron derivative, chrysodium derivative, spirofluorene derivative, iridium complex, or platinum complex.

[0091] The thickness of the light-emitting layer of the present invention can be 5-60 nm, preferably 10-50 nm, and more preferably 20-45 nm.

[0092] A hole-blocking layer can be disposed above the emissive layer. The triplet (T1) energy level of the hole-blocking layer material is higher than the T1 energy level of the main emissive layer material, thus preventing energy loss from the emissive layer material. The HOMO energy level of the material is lower than the HOMO energy level of the main emissive layer material, also serving to block holes. Simultaneously, the hole-blocking layer material is required to have high electron mobility to facilitate electron transport and reduce the power consumption of the device. Hole-blocking layer materials meeting these conditions can be triazine derivatives, azirene derivatives, etc. Triazine derivatives are preferred, but not limited to these.

[0093] As the hole-blocking layer of the organic electroluminescent device of the present invention, the hole-blocking layer materials for organic electroluminescent devices disclosed in the prior art can be used:

[0094]

[0095] The thickness of the hole blocking layer of the present invention can be 2-200 nm, preferably 5-150 nm and more preferably 5-50 nm, but the thickness is not limited to this range.

[0096] An electron transport layer may be disposed above a hole blocking layer. The electron transport layer material is one that readily receives electrons from the cathode and transfers the received electrons to the light-emitting layer. The electron transport layer comprises one or more nitrogen-containing heterocyclic compounds of the present invention. Preferably, the electron transport layer consists of the nitrogen-containing heterocyclic compound of the present invention and other electron transport layer materials. More preferably, the other electron transport layer materials are commonly used electron transport materials in the art. Most preferably, the electron transport layer consists of the nitrogen-containing heterocyclic compound of the present invention and Liq, wherein the ratio of the nitrogen-containing heterocyclic compound of the present invention to the other electron transport layer materials is 1:9-9:1, preferably 2:8-8:2, more preferably 4:6-6:4, and most preferably 5:5.

[0097] The thickness of the electron transport layer of the present invention can be 10-80 nm, preferably 20-60 nm, and more preferably 25-45 nm.

[0098] According to the present invention, an electron injection layer may be disposed between the electron transport layer and the cathode. The electron injection layer material is generally preferably a material with a low work function, which facilitates electron injection into the organic functional material layer. Preferably, the electron injection layer material is an N-type metal material. As the electron injection layer material for the organic electroluminescent device of the present invention, the following electron injection layer materials for organic electroluminescent devices disclosed in the prior art can be used: LiF, Cs₂CO₃, CsF, Csq, NaF, MgF₂, CaF₂, Al₂O₃, and Yb.

[0099] The thickness of the electron injection layer of the present invention can be 0.1-5 nm, preferably 0.5-3 nm and more preferably 0.8-1.5 nm, but the thickness is not limited to this range.

[0100] According to the present invention, as described above, the second electrode can be either a cathode or an anode. In this invention, the second electrode is used as the cathode. The material used to form the cathode can be a material with low work function, such as a metal, alloy, conductive compound, or a mixture thereof. Non-limiting examples of cathode materials may include lithium (Li), ytterbium (Yb), magnesium (Mg), aluminum (Al), calcium (Ca), as well as aluminum-lithium (Al-Li), magnesium-indium (Mg-In), and magnesium-silver (Mg-Ag). The thickness of the cathode depends on the material used, typically 5-100 nm, preferably 7-50 nm, and more preferably 10-25 nm.

[0101] Optionally, to improve the light extraction efficiency of the organic electroluminescent device, a light extraction layer (i.e., a CPL layer) may be added above the second electrode (i.e., the cathode) of the device. The following compounds disclosed in the art in the prior art can be used as CPL layer materials.

[0102]

[0103] The thickness of the CPL layer is typically 5-300 nm, preferably 20-100 nm, and more preferably 40-80 nm.

[0104] Organic electroluminescent devices may also include an encapsulation structure. The encapsulation structure may be a protective structure that prevents external substances such as moisture and oxygen from entering the organic layer of the organic electroluminescent device. The encapsulation structure may be, for example, a can, such as a glass or metal can; or a thin film covering the entire surface of the organic layer.

[0105] Methods for fabricating organic electroluminescent devices

[0106] The present invention provides a method for fabricating the aforementioned organic electroluminescent device, comprising sequentially laminating a first electrode, a multilayer organic thin film layer, and a second electrode on a substrate. The multilayer organic thin film layer is formed by sequentially laminating a hole transport region, a light-emitting layer, and an electron transport region on the first electrode from bottom to top. The hole transport region is formed by sequentially laminating a hole injection layer, a hole transport layer, and an electron blocking layer on the first electrode from bottom to top, and the electron transport region is formed by sequentially laminating a hole blocking layer, an electron transport layer, and an electron injection layer on the light-emitting layer from bottom to top. Optionally, a CPL layer may also be laminated on the second electrode to improve the light extraction efficiency of the organic electroluminescent device.

[0107] Regarding lamination, methods such as vacuum deposition, vacuum evaporation, spin coating, casting, LB method, inkjet printing, laser printing, or LITI can be used, but are not limited to these. Among them, vacuum evaporation refers to heating the material and depositing it onto the substrate in a vacuum environment.

[0108] In this invention, vacuum evaporation is preferably used to form the various layers, wherein the vapor deposition process can be carried out at a temperature of about 100-500°C for about 10... -8 -10 -2 The vacuum degree and about Vacuum evaporation is performed at a rate of [missing information]. The vacuum level is preferably 10 [missing information]. -6 -10 -2 Torr, more preferably 10 -5 -10 -3 Torr. The rate is approximately More preferably, about

[0109] In addition, it should be noted that the materials used to form each layer described in this invention can be used as a single layer by forming a film on their own, or they can be used as a single layer by mixing with other materials to form a film. They can also be a stacked structure between layers that are formed on their own, a stacked structure between layers that are formed by mixing, or a stacked structure between layers that are formed on their own and layers that are formed by mixing.

[0110] Display device

[0111] The present invention also relates to a display device including the aforementioned organic electroluminescent devices, particularly a flat panel display device. In a preferred embodiment, the display device may include one or more of the aforementioned organic electroluminescent devices, and in the case of multiple devices, the devices are stacked laterally or vertically. The display device may also include at least one thin-film transistor. The thin-film transistor may include a gate electrode, a source electrode and a drain electrode, a gate insulating layer and an active layer, wherein one of the source electrode and the drain electrode may be electrically connected to a first electrode of the organic electroluminescent device. The active layer may include crystalline silicon, amorphous silicon, organic semiconductor or oxide semiconductor, but is not limited thereto.

[0112] Exemplary embodiments have been disclosed herein. While specific terminology has been used, it is intended and interpreted in a general and descriptive sense only, and not for limiting purposes. In some instances, as will be apparent to those skilled in the art upon the filing of this application, features, characteristics, and / or elements described in connection with particular embodiments may be used alone or in combination with features, characteristics, and / or elements described in connection with other embodiments, unless specifically indicated otherwise. Accordingly, those skilled in the art will understand that various changes in form and detail may be made without departing from the spirit and scope of the invention.

[0113] The following examples are intended to better explain the present invention, but the scope of the invention is not limited thereto.

[0114] Example

[0115] I. Compound Preparation Examples

[0116] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0117] All raw materials involved in the synthesis embodiments of the present invention can be purchased from the market or obtained by conventional preparation methods in the art;

[0118] Example 1: Synthesis of Compound 8:

[0119]

[0120]

[0121] Preparation of intermediate T1: In a round-bottom flask, under nitrogen protection, raw material B1 (9.16 g, 40 mmol), raw material A1 (15.47 g, 41 mmol), K2CO3 (6.22 g, 45 mmol), tetrahydrofuran (240 mL), and water (120 mL) were added sequentially. Nitrogen gas was purged for 30 min to replace the air. Palladium acetate (0.04 g, 0.18 mmol) and 2-dicyclohexylphosphine-2',4',6'-triisopropylbiphenyl (0.07 g, 0.15 mmol) were added, and the mixture was heated under reflux for 20 h. TLC analysis of the reaction solution showed that starting material B1 reacted completely. After the reaction was complete, the reaction system was naturally cooled to room temperature, and the solvent was removed by rotary evaporation. The residue was dissolved in 100 mL of dichloromethane, washed with 50 mL of water, poured into a separatory funnel, shaken, and allowed to stand for separation. The aqueous phase was extracted with dichloromethane (60 mL * 4). The organic phases were combined, dried with anhydrous magnesium sulfate, filtered, and the filtrate was rotary evaporated to remove dichloromethane to obtain the crude product. The crude product was purified by silica gel column chromatography to obtain intermediate T1. LC-MS: Measured value: 444.07 ([M+H) + Theoretical value: 443.12.

[0122] Preparation of compound 8: Refer to the preparation of intermediate T1, except that raw material B1 is replaced by raw material C1 and raw material A1 is replaced by intermediate T1.

[0123] Example 2: Synthesis of compound 22:

[0124]

[0125] Preparation of intermediate T2: Refer to the preparation of intermediate T1, except that raw material A2 replaces raw material A1, and raw material B2 replaces raw material B1. LC-MS: Test value: 367.86 (M+H) + Theoretical value: 366.98.

[0126] Preparation of intermediate T3: Refer to the preparation of intermediate T1, except that raw material B1 is replaced by raw material C2, and raw material A1 is replaced by intermediate T2. LC-MS: Test value: 597.22 (M+H) + Theoretical value: 596.18.

[0127] Preparation of compound 22: Refer to the preparation of compound 8, except that starting material C3 is used instead of starting material C1, and intermediate T3 is used instead of intermediate T1.

[0128] Example 3: Synthesis of compound 56:

[0129]

[0130] Preparation of intermediate T4: Refer to the preparation of intermediate T1, except that raw material A3 replaces raw material A1, and raw material B3 replaces raw material B1. LC-MS: Test value: 495.21 (M+H) + Theoretical value: 494.13.

[0131] Preparation of compound 56: Refer to the preparation of compound 8, except that intermediate T1 is replaced by intermediate T4 and starting material C1 is replaced by starting material C4.

[0132] Example 4: Synthesis of compound 113:

[0133]

[0134]

[0135] Preparation of intermediate T5: Refer to the preparation of intermediate T1, except that starting material B4 is used instead of starting material B1. LC-MS: Test value: 509.01 (M+H) + Theoretical value: 508.13.

[0136] Preparation of intermediate V1: Under nitrogen protection, in a round-bottom flask, raw material E1 (7.32 g, 25 mmol), raw material D1 (8.58 g, 26 mmol), KOAC (4.42 g, 45 mmol), and dioxane (80 mL) were added sequentially. Nitrogen gas was purged for 30 min to replace the air, and Pd(PPh3)4 (0.35 g, 0.3 mmol) was added. The mixture was heated under reflux for 15 h under nitrogen protection. TLC analysis of the reaction solution showed that the reaction of raw material E1... After the reaction was complete, the reaction system was naturally cooled to room temperature. The solvent was removed by rotary evaporation. The residue was dissolved in 380 mL of dichloromethane, washed with 260 mL of water, poured into a separatory funnel, shaken, and allowed to stand for separation. The aqueous phase was extracted with dichloromethane (50 mL * 3). The organic phases were combined, dried with anhydrous magnesium sulfate, filtered, and the filtrate was rotary evaporated to remove dichloromethane to obtain the crude product. The crude product was purified by silica gel column chromatography to obtain intermediate V1. LC-MS: Measured value: 461.36 ([M+H) + Theoretical value: 460.21.

[0137] Preparation of compound 113: Refer to the preparation of compound 8, except that intermediate T5 is used instead of intermediate T1 and intermediate V1 is used instead of starting material C1.

[0138] Example 5: Synthesis of compound 195:

[0139]

[0140]

[0141] Preparation of intermediate T6: Refer to the preparation of intermediate T1, except that starting material B5 is used instead of starting material B1. LC-MS: Test value: 419.09 ([M+H]) + Theoretical value: 418.12.

[0142] Preparation of intermediate V2: Refer to the preparation of intermediate V1, except that starting material E2 is used instead of starting material E1. LC-MS: Test value: 460.18 (M+H) + Theoretical value: 459.21.

[0143] Preparation of compound 195: Refer to the preparation of compound 113, except that intermediate V1 is replaced by intermediate V2 and intermediate T5 is replaced by intermediate T6.

[0144] Example 6: Synthesis of compound 212:

[0145]

[0146] Preparation of compound 212: Refer to the preparation of compound 113, except that intermediate T5 is replaced by intermediate T6.

[0147] Example 7: Synthesis of compound 226:

[0148]

[0149]

[0150] Preparation of intermediate V3: Refer to the preparation of intermediate V1, except that starting material E3 is used instead of starting material E1. LC-MS: Test value: 461.14 ([M+H]) + Theoretical value: 460.21.

[0151] Preparation of compound 226: Refer to the preparation of compound 113, except that intermediate V1 is replaced by intermediate V3 and intermediate T5 is replaced by intermediate T6.

[0152] Example 8: Synthesis of compound 240:

[0153]

[0154] Preparation of intermediate T7: Refer to the preparation of intermediate T1, except that starting material B6 is used instead of starting material B1. LC-MS: Test value: 469.25 (M+H) + Theoretical value: 468.14.

[0155] Preparation of intermediate T8: Refer to the preparation of intermediate T1, except that raw material B7 replaces raw material B1, and raw material E4 replaces raw material A1. LC-MS: Test value: 293.13 ([M+H]) + Theoretical value: 292.05.

[0156] Preparation of intermediate V4: Refer to the preparation of intermediate V1, except that intermediate T8 is used instead of starting material E1. LC-MS: Measured value: 461.16 (M+H) + Theoretical value: 460.21.

[0157] Preparation of compound 240: Refer to the preparation of compound 113, except that intermediate V1 is replaced by intermediate V4 and intermediate T5 is replaced by intermediate T7.

[0158] Example 9: Synthesis of compound 256:

[0159]

[0160] Preparation of intermediate T9: Refer to the preparation of intermediate T6, except that raw material A1 is replaced with raw material A3. LC-MS: Test value: 420.01 (M+H) + Theoretical value: 419.12.

[0161] Preparation of compound 256: Refer to the preparation of compound 195, except that intermediate T6 is replaced by intermediate T9.

[0162] Example 10: Synthesis of compound 288:

[0163]

[0164]

[0165] Preparation of intermediate T10: Refer to the preparation of intermediate T2, except that starting material B2 is replaced with starting material B8. LC-MS: Test value: 341.87 (M+H) + Theoretical value: 340.96.

[0166] Preparation of intermediate T11: Refer to the preparation of compound 8, except that intermediate T1 was replaced by intermediate T10. LC-MS: Measured value: 570.08 ([M+H]). + Theoretical value: 569.17.

[0167] Preparation of compound 288: Refer to the preparation of compound 8, except that intermediate T1 is replaced by intermediate T11 and starting material C5 is replaced by starting material C1.

[0168] Example 11: Synthesis of compound 292:

[0169]

[0170] Preparation of intermediate T12: Refer to the preparation of intermediate T10, except that starting material B8 is replaced with starting material B9. LC-MS: Test value: 316.96 (M+H) + Theoretical value: 315.97.

[0171] Preparation of intermediate W1: Refer to the preparation of compound 195, except that intermediate T6 was replaced with intermediate T12. LC-MS: Measured value: 570.22 ([M+H]). + Theoretical value: 569.17.

[0172] Preparation of compound 292: Refer to the preparation of compound 8, except that intermediate T1 is replaced by intermediate W1 and starting material C5 is replaced by starting material C1.

[0173] Example 12: Synthesis of compound 312:

[0174]

[0175] Preparation of intermediate W2: Refer to the preparation of intermediate W1, except that intermediate T12 is prepared using starting material A4. LC-MS: Test value: 520.19 (M+H) + Theoretical value: 519.15.

[0176] Preparation of compound 312: Refer to the preparation of compound 8, except that intermediate T1 is replaced by intermediate W2 and starting material C3 is replaced by starting material C1.

[0177] Example 13: Synthesis of compound 133:

[0178]

[0179] Preparation of intermediate V5: Refer to the preparation of intermediate V2, except that starting material E5 is used instead of starting material E2. LC-MS: Test value: 536.33 ([M+H)) + Theoretical value: 535.24.

[0180] Preparation of compound 133: Refer to the preparation of compound 256, except that intermediate V2 is replaced by intermediate V5.

[0181] Example 14: Synthesis of compound 127:

[0182]

[0183] Preparation of intermediate V6: Refer to the preparation of intermediate V5, except that starting material E6 is used instead of E5. LC-MS: Test value: 536.17 (M+H) + Theoretical value: 535.24.

[0184] Preparation of compound 127: Refer to the preparation of compound 256, except that intermediate V2 is replaced by intermediate V6.

[0185] The structural characterization of the compounds obtained in each embodiment is shown in Table 1:

[0186] Table 1

[0187]

[0188]

[0189] II. Device Fabrication Examples

[0190] The following describes in detail the application effects of the compounds synthesized according to the present invention as electron transport materials in devices through device Examples 1-14 and device Comparative Examples 1-9. Device Examples 1-14 are manufactured using the same process as Comparative Examples 1-9, employing the same substrate and electrode materials with consistent electrode film thickness. The only difference is the change in the electron transport layer material. The device layer structures are shown in Table 2, and the performance test results for each device are shown in Table 3.

[0191] The molecular structural formulas of the relevant materials are shown below:

[0192]

[0193]

[0194] The structures of compounds ET-1, ET-2, ET-3, ET-4, ET-5, ET-6, ET-7, ET-8, and ET-9 are shown above. All of these materials were commercially available.

[0195] Device Comparison Example 1

[0196] The specific preparation process is as follows:

[0197] like Figure 1 As shown, the transparent substrate layer 1 is transparent glass. Ag (100nm) is deposited as the anode layer 2. On the anode layer 2, HT-1 and P-1 with a thickness of 10nm are deposited using a vacuum evaporation apparatus as the hole injection layer 3, with a mass ratio of HT-1 to P-1 of 97:3. Next, HT-1 with a thickness of 130nm is deposited as the hole transport layer 4. Subsequently, EB-1 with a thickness of 5nm is deposited as the electron blocking layer 5. After the electron blocking materials are deposited, the light-emitting layer 6 of the organic electroluminescent device is fabricated, using BH-1 as the host material and BD-1 as the dopant material, with a doping ratio of 3% by weight, and a light-emitting layer thickness of 20nm. After the light-emitting layer 6, HB-1 is deposited with a thickness of 5nm as the hole blocking layer 7. On the hole blocking layer 7, ET-1 and Liq are deposited with a mass ratio of ET-1 to Liq of 1:1. The vacuum-deposited film of this material is 30 nm thick, and this layer is the electron transport layer 8. On the electron transport layer 8, a 1 nm thick LiF layer is fabricated using a vacuum evaporation apparatus; this layer is the electron injection layer 9. On the electron injection layer 9, a 16 nm thick Mg:Ag electrode layer is fabricated using a vacuum evaporation apparatus, with a Mg to Ag mass ratio of 1:9; this layer is used as the cathode layer 10. On the cathode layer 10, a 65 nm thick CP-1 layer is vacuum-deposited as the CPL layer 11.

[0198] Device Examples 1-14 and Device Comparative Examples 2-9 were prepared in a similar manner to Device Comparative Example 1, except that the electron transport layer materials in Table 2 below were used.

[0199] Table 2

[0200]

[0201]

[0202]

[0203] III. Device Testing Examples

[0204] The devices fabricated in Part II were tested, including their drive voltage and LT95 lifetime. The voltage was measured using an IVL (current-voltage-luminance) testing system (Suzhou Fushida Scientific Instruments Co., Ltd.), with a current density of 10 mA / cm². 2 LT95 refers to the time it takes for the device's brightness to decay to 95% of its initial brightness, and the current density during the test is 30 mA / cm². 2 The lifetime testing system is the EAS-62C OLED device lifetime tester from System Technology Inc., Japan. The high-temperature lifetime test temperature is 85℃. The high-temperature lifetime LT95 refers to the time it takes for the device brightness to decay to 95% of its initial brightness. The current density during the test is 20mA / cm². 2 ;

[0205] The test results are shown in Table 3 below.

[0206] Table 3

[0207]

[0208]

[0209] As can be seen from the device test data in Table 3 above, compared with the comparative devices using ET-1, ET-2, ET-3, ET-4, ET-5, ET-6, ET-7, ET-8, and ET-9 as electron transport layer materials, the device prepared using the compound of this invention as the electron transport layer material has a significantly lower driving voltage and a longer device lifespan. For example, its lifespan is basically more than 1.29 times that of the comparative devices 1-11.

[0210] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A compound containing a nitrogen-containing heterocyclic structure, characterized in that, The structure of the compound is shown in general formula (1): In general formula (1), X1 to X3 are each independently represented as nitrogen atom or CH, and at least one of them is represented as nitrogen atom; X4 to X6 are each independently represented as nitrogen atom or CH, and at least one of them is represented as nitrogen atom; Among them, X1 to X6 can be represented by a maximum of five nitrogen atoms; R1 and R3 are each independently represented as hydrogen atoms, and R... a Substituted or unsubstituted phenyl, by R a Substituted or unsubstituted naphthyl groups, derived from R a Substituted or unsubstituted diphenyl, derived from R a Substituted or unsubstituted dibenzofuranyl; R2 represents a hydrogen atom, a phenyl group, and R... a Substituted or unsubstituted naphthyl groups, derived from R a Substituted or unsubstituted diphenyl, derived from R a Substituted or unsubstituted dibenzofuranyl; Among R1, R2, and R3, there is exactly one that is not represented as a hydrogen atom; Ar1 and Ar2 can be the same or different, and each can be independently represented by R. b Substituted or unsubstituted phenyl, by R b Substituted or unsubstituted naphthyl groups, derived from R b Substituted or unsubstituted diphenyl, derived from R b Substituted or unsubstituted triphenyl, by R b Substituted or unsubstituted pyridinyl groups, derived from R b Substituted or unsubstituted pyrimidine groups, derived from R b Substituted or unsubstituted dibenzofuranyl; Ar3 and Ar4 can be the same or different, and each can be independently represented by R. c Substituted or unsubstituted phenyl, by R c Substituted or unsubstituted naphthyl groups, derived from R c Substituted or unsubstituted diphenyl, derived from R c Substituted or unsubstituted triphenyl, by R c Substituted or unsubstituted pyridinyl groups, derived from R c Substituted or unsubstituted pyrimidine groups, derived from R c Substituted or unsubstituted dibenzofuranyl; The R a Represented as cyano, phenyl, diphenyl, triphenyl, pyridyl, pyrimidinyl; The R b Represented as phenyl, diphenyl, triphenyl, pyridyl, pyrimidinyl; The R c Represented as cyano, phenyl, diphenyl, triphenyl, pyridyl, pyrimidinyl; At least one of Ar3, Ar4, R1, R2, and R3 is substituted with a cyano group.

2. The compound with a nitrogen-containing heterocyclic structure according to claim 1, characterized in that, The structure of the compound is shown in any one of general formulas (2-1) to (2-4): In general formulas (2-1) to (2-4), the meanings of Ar1, Ar2, Ar3, Ar4, R1, R2, R3, X1, X2, and X3 are the same as those defined in claim 1.

3. The compound with a nitrogen-containing heterocyclic structure according to claim 1, characterized in that, The structure of the compound is shown in any one of general formulas (3-1) to (3-4): In general formulas (3-1) to (3-4), the meanings of Ar1, Ar2, Ar3, Ar4, R1, R2, R3, X4, X5, and X6 are the same as those defined in claim 1.

4. The compound with a nitrogen-containing heterocyclic structure according to claim 1, characterized in that, The structure of the compound is shown in any one of general formulas (4-1) to (4-4): In general formulas (4-1) to (4-4), the meanings of Ar1, Ar2, Ar3, Ar4, R1, R2, and R3 are the same as those defined in claim 1.

5. The compound with a nitrogen-containing heterocyclic structure according to claim 1, characterized in that, The structure of the compound is shown in any one of general formulas (5-1) to (5-4): In general formulas (5-1) to (5-4), the meanings of Ar1, Ar2, Ar3, Ar4, R1, R2, and R3 are the same as those defined in claim 1.

6. The compound with a nitrogen-containing heterocyclic structure according to claim 1, characterized in that, The structure of the compound is shown in any one of general formulas (6-1) to (6-3): In general formulas (6-1) to (6-3), the meanings of Ar1, Ar2, Ar3, Ar4, R1, R2, and R3 are the same as those defined in claim 1; Each of X1 to X3 is independently represented as a nitrogen atom or CH, and two or three of them are represented as nitrogen atoms; Each of X4 to X6 is independently represented as a nitrogen atom or CH, and two or three of them are represented as nitrogen atoms; Four or five of X1 to X6 are represented by nitrogen atoms.

7. The compound with a nitrogen-containing heterocyclic structure according to claim 1, characterized in that, The specific structure of the compound is any one of the following structures:

8. An organic electroluminescent device, comprising a substrate, a first electrode, and a second electrode, wherein a multilayer organic thin film layer is disposed between the first electrode and the second electrode, characterized in that, The organic thin film layer contains a compound with a nitrogen-containing heterocyclic structure as described in any one of claims 1 to 7.

9. The organic electroluminescent device according to claim 8, characterized in that, The organic thin film layer includes a hole transport region thin film layer, a light emission region thin film layer, and an electron transport region thin film layer, wherein the electron transport region thin film layer contains a compound with a nitrogen-containing heterocyclic structure as described in any one of claims 1 to 7; Preferably, the electron transport region thin film layer includes an electron transport layer containing a compound with a nitrogen-containing heterocyclic structure as described in any one of claims 1 to 7.

10. The organic electroluminescent device according to claim 9, characterized in that, The hole transport region thin film layer comprises a hole injection layer, a hole transport layer, and an electron blocking layer; the electron transport region thin film layer comprises a hole blocking layer, an electron transport layer, and an electron injection layer; and the electron transport layer contains a compound with a nitrogen-containing heterocyclic structure as described in any one of claims 1 to 7.

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