Compound with electron transport function, organic electroluminescent device containing same and application

Abstract

The application provides a compound with an electron transport function, an organic electroluminescent device containing the same and application, the structure of the compound mainly comprises a 9-alkyl-9-phenylfluorenyl group, a phenanthryl group and a triazine group, the 9-alkyl-9-phenylfluorenyl group is one of the core structures, the fluorene itself is a condensed ring aromatic hydrocarbon with good planarity, the alkyl group and the phenyl group introduced at the 9th position generate strong steric repulsion with the fluorene ring itself, forming a three-dimensional, non-planar 'propeller' structure, the non-planar structure can effectively inhibit the close packing of molecules in a solid state, thereby preventing concentration quenching and formation of an excimer caused by pi-pi stacking, achieving higher solid-state light-emitting efficiency, and the rigid, non-planar structure can also effectively improve the thermal stability of the material and improve the service life of the device. The compound of the application can be used as an electron transport layer and a hole blocking layer in a light-emitting device, so that the device has low driving voltage, high light-emitting efficiency and long service life.

Description

Technical Field

[0001] This invention belongs to the field of organic electroluminescence, specifically relating to a compound with electron transport function, an organic electroluminescent device containing the compound, and its applications. Background Technology

[0002] Organic light-emitting devices (OLEDs) convert electrical energy into light by applying electricity to organic electroluminescent materials. They typically consist of an anode, a cathode, and an organic layer formed between or outside the two electrodes. This organic layer can include hole injection layers, hole transport layers, light-emitting auxiliary layers, electron blocking layers, light-emitting layers, electron buffer layers, electron transport layers, electron injection layers, and capping layers. Electron transport layers prevent luminous quenching caused by direct contact between the cathode and the light-emitting layer. Hole blocking layers increase the probability of electron-hole recombination at the interface between the light-emitting layer and the device, thus increasing the device's luminous efficiency. Both layers play a crucial role in determining the efficiency and stability of OLEDs.

[0003] Materials with electron transport capabilities typically require a low LUMO (lowest unoccupied molecular orbital) energy level and generally contain electron-withdrawing groups such as halogens, pyridines, triazines, triazoles, and hydroxyl groups to facilitate electron gain. Furthermore, the LUMO energy level should be matched as closely as possible to the work function of the cathode to maximize electron injection and transport. Simultaneously, the HOMO (highest occupied molecular orbital) of the electron transport material should be as high as possible to block the transport of holes from the luminescent layer to the cathode, thus confining more holes within the luminescent layer to form excitons and generate light. Triazine groups, with their strong electron-withdrawing properties and higher electron affinity than most heterocyclic aromatic hydrocarbons, can effectively deepen the LUMO energy level, facilitating electron injection from the electrode and thereby improving luminescence efficiency and reducing energy consumption. At the same time, triazine groups also have the potential to increase the HOMO energy level, enabling the material to acquire hole-blocking capabilities. The 1,3,5-triazine group combines the strong electron affinity of triazine with the good thermal properties and high film quality of the large π framework. At the same time, its 2, 4, and 6 sites are easily attacked by nucleophiles, which facilitates the synthesis of its derivatives.

[0004] However, there are few existing materials that combine electron transport and hole blocking capabilities with excellent device performance. Moreover, the electron conduction rate of most materials is much lower than the hole conduction rate, resulting in only a slight improvement in the lifetime and luminous efficiency of the fabricated devices. Therefore, designing and finding a stable and efficient compound as a novel organic electroluminescent material to overcome its shortcomings in practical applications is a key focus and future research trend in organic electroluminescent device materials research. Summary of the Invention

[0005] The main objective of this invention is to provide a compound with electron transport function, an organic electroluminescent device containing the compound, and its applications. The compound is highly efficient and stable and has electron transport function. The compound structure is mainly composed of 9-alkyl-9-phenylfluorenyl, phenanthrene, and triazine groups. It can be used as an electron transport layer and hole blocking layer in an organic electroluminescent device, giving the device excellent characteristics such as low driving voltage, high luminous efficiency, and long service life.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] The first objective of this invention is to provide a material with electron transport capabilities, having the structure shown in Chemical Formula I:

[0008] ;

[0009] in,

[0010] R is independently selected from substituted or unsubstituted C1-C8 alkyl groups;

[0011] L is independently selected from the linking bond, substituted or unsubstituted C6-C18 aryl group;

[0012] Ar1 and Ar2 are independently selected from substituted or unsubstituted C6-C30 aryl and substituted or unsubstituted C3-C30 heteroaryl, respectively, wherein the heteroatom contains at least one of O, S, N, Si, and Se;

[0013] Ar3 and Ar4 are independently selected from hydrogen, deuterium, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C3-C30 heteroaryl, wherein the heteroatom contains at least one of O, S, N, Si, and Se;

[0014] R1 and R2 are independently selected from hydrogen and deuterium, respectively;

[0015] n1 is independently selected from 0, 1, 2, 3, 4, 5, 6, 7, 8;

[0016] n2 is independently selected from 0, 1, 2, 3, and 4;

[0017] In the chemical formula I, any hydrogen atom can be independently replaced by deuterium.

[0018] Furthermore, chemical formula I has the following structures: IA~IF

[0019]

[0020] Among them, R3-R 11 They are each independently selected from hydrogen and deuterium;

[0021] n3, n4, n5, n11 Each of the numbers 0, 1, 2, 3, and 4 is selected independently.

[0022] n6, n8, and n9 are independently selected from 0, 1, 2, and 3, respectively;

[0023] n7 is independently selected from 0, 1, 2, 3, 4, and 5;

[0024] n 10 Selected independently from 0, 1, and 2.

[0025] Furthermore, R is independently selected from substituted or unsubstituted methyl, substituted or unsubstituted ethyl, substituted or unsubstituted propyl, substituted or unsubstituted isopropyl, substituted or unsubstituted tert-butyl;

[0026] Furthermore, L is independently selected from the linking bond, substituted or unsubstituted phenyl, substituted or unsubstituted biphenyl, substituted or unsubstituted naphthyl;

[0027] Furthermore, Ar1 and Ar2 are independently selected from substituted or unsubstituted C6-C20 aryl groups and substituted or unsubstituted C5-C18 heteroaryl groups, respectively, wherein the heteroatom contains at least one of O, S, N, Si, and Se;

[0028] Furthermore, Ar3 and Ar4 are independently selected from hydrogen, deuterium, substituted or unsubstituted C6-C12 aryl, substituted or unsubstituted C5-C18 heteroaryl, wherein the heteroatom contains at least one of O, S, N, Si, and Se;

[0029] Furthermore, Ar1 and Ar2 are each independently selected from the following structures:

[0030]

[0031] In the above substituents, any H can be independently substituted by deuterium.

[0032] Furthermore, Ar3 and Ar4 are independently selected from hydrogen, deuterium, and the following structures:

[0033] ;

[0034] In the above substituents, any H can be independently substituted by deuterium;

[0035] Indicates the linking site of a functional group.

[0036] The term "substituted or unsubstituted" means substituted by one, two or more substituents selected from the following: deuterium, cyano, halogen, methyl, ethyl, propyl, butyl, tert-butyl, cyclopentane, cyclohexane, phenyl, biphenyl, naphthyl, fluorenyl, dimethylfluorenyl, phenanthrene, triphenylene, carbazolyl, furanyl, thiophene, pyrrole, pyridyl, benzofuranyl, benzothiophene, isobenzofuranyl, dibenzofuranyl, dibenzothiophene, or substituted by two or more substituents linked together from the substituents shown above, or has no substituents.

[0037] Furthermore, chemical formula I has any one of the structures of compounds 1-568:

[0038] .

[0039] The second objective of this invention is to provide a method for preparing a material having electron transport function as described above.

[0040] It should be noted that the material with electron transport function in this invention can be prepared by methods known to those skilled in the art. Alternatively, the following reaction process is preferred for preparation, and the specific operation is as follows:

[0041] Step 1 specifically includes the following processes:

[0042] Cool to -78℃, dissolve raw material B (1.1-1.5 eq) in THF, replace with nitrogen three times, stir for 10-30 min, slowly add n-butyllithium (1.1-1.5 eq) to the reaction flask, react for 1-4 h, dissolve raw material A (1.0 eq) in tetrahydrofuran, and then slowly add the solution of raw material A dropwise to the reaction flask, stir evenly, stop refrigeration, and continue the reaction at room temperature for 2-18 h; detect the reaction by thin-layer chromatography. After the reaction is complete, wash three times with water and retain the organic phase. Then extract the aqueous phase with dichloromethane, combine the organic phases and concentrate, and purify the intermediate 1 by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V=1:2-1:6).

[0043] Step 2 specifically includes the following processes:

[0044] Intermediate 1 (1.0 eq) was dissolved in dichloromethane. Triethylsilane (1.1-2.0 eq) was added while stirring at -10℃. After stirring for 15-60 min, methanesulfonic acid (2.0-4.0 eq) was added and stirring was continued for 10-30 min. The mixture was then transferred to room temperature and reacted for 1-4 h. The reaction was detected by thin-layer chromatography. After the reaction was completed, water was added to the reaction solution and stirred. The mixture was extracted and separated, retaining the organic phase. The aqueous phase was then extracted with dichloromethane. The organic phases were combined and concentrated. Intermediate 2 was obtained by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V=1:4-1:12) or pure petroleum ether.

[0045] Step 3 specifically includes the following processes:

[0046] Intermediate 2 (1.0 eq) was dissolved in THF and stirred at room temperature until dissolved. Then, t-BuOK (2.0-10.0 eq) was slowly added to the reaction flask and stirred for 1 h. Then, starting material C (3.0-8.0 eq) was slowly added dropwise, and the temperature was raised to 70-90℃. The reaction was carried out for 6-20 h. The reaction was detected by thin-layer chromatography. After the reaction was completed, the temperature was lowered slightly, and the mixture was filtered with diatomaceous earth to remove salt. Water and dichloromethane were added to the filtrate for separation and extraction. The organic phase was retained and concentrated. Intermediate 3 was obtained by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V=1:4-1:12).

[0047] Step 4 specifically includes the following processes:

[0048] Intermediate 3 (1.0 eq), pinacol diborate (1.0-1.5 eq), and potassium acetate (2.0-4.0 eq) were added to a reaction flask, followed by 1,4-dioxane. Nitrogen gas was introduced, and under nitrogen protection, tris(dibenzylacetone)dipalladium (0.02-0.10 eq) and X-Phos (0.1-0.2 eq) were added. The mixture was then heated to 110-120 °C and refluxed for 2-30 h. The reaction was detected by thin-layer chromatography. After the reaction was completed, the temperature was slightly lowered, and the mixture was filtered with diatomaceous earth to remove salts and catalysts. Water and dichloromethane were added to the filtrate for separation and extraction. The organic phase was retained and concentrated. Intermediate 4 was obtained by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V=1:3-1:10).

[0049] Step 5 specifically includes the following processes:

[0050] Intermediate 4 (1.0 eq) and starting material D (1.0-1.3 eq) were added to a reaction flask, followed by a mixed solution of toluene, ethanol, and water (V:V:V = 3:1:1). Nitrogen gas was introduced, and under nitrogen protection, tetrakis(triphenylphosphine)palladium (0.01-0.05 eq) and potassium carbonate (2.0-4.0 eq) or palladium acetate (0.02-0.06 eq), X-Phos (0.1-0.3 eq) and cesium carbonate (2.0-4.0 eq) were added. The mixture was then heated to 80-100℃ and refluxed for 2-30 h. The mixture was filtered with diatomaceous earth to remove salts and catalysts. Water and dichloromethane were added to the filtrate for separation and extraction. The organic phase was retained and concentrated. Intermediate 5 was obtained by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V = 1:3-1:10).

[0051] Note: In this reaction step, the starting material D contains two halogens. This is achieved by utilizing the characteristic of reactivity I > Br > Cl in the Suzuki coupling reaction, and by controlling the reaction conditions and reaction sites. The intermediate containing the target structure was then prepared. The reaction was purified by column chromatography or through a silica gel funnel to remove byproducts and obtain the target compound. For the reaction mechanism, please refer to:

[0052] Organometallic Chemistry (6th Edition), Robert H. Crabtree, published by East China University of Science and Technology Press, Shanghai, September 00, 2017, ISBN: 978-7-5628-5111-0, page 388.

[0053] Organic Chemistry and Optoelectronic Materials Experiment Tutorial, Chen Runfeng, Publisher: Southeast University Press, Publication Date: 2019-11-00, ISBN: 9787564184230, Page 174.

[0054] Step 6 specifically includes the following processes:

[0055] Intermediate 5 (1.0 eq), pinacol diborate (1.0-1.5 eq), and potassium acetate (2.0-4.0 eq) were added to a reaction flask, followed by 1,4-dioxane. Nitrogen gas was introduced, and under nitrogen protection, tris(dibenzylacetone)dipalladium (0.02-0.10 eq) and X-Phos (0.1-0.2 eq) were added. The mixture was then heated to 110-120 °C and refluxed for 2-30 h. The reaction was detected by thin-layer chromatography. After the reaction was completed, the temperature was slightly lowered, and the mixture was filtered with diatomaceous earth to remove salts and catalysts. Water and dichloromethane were added to the filtrate for separation and extraction. The organic phase was retained and concentrated. Intermediate 6 was obtained by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V=1:3-1:10).

[0056] Step 7 specifically includes the following processes:

[0057] Intermediate 6 (1.0 eq) and starting material E (1.0-1.3 eq) were added to a reaction flask, followed by a mixed solution of toluene, ethanol, and water (V:V:V = 3:1:1). Nitrogen gas was introduced, and under nitrogen protection, tetrakis(triphenylphosphine)palladium (0.01-0.05 eq) and potassium carbonate (2.0-4.0 eq) or palladium acetate (0.02-0.06 eq), X-Phos (0.1-0.3 eq) and cesium carbonate (2.0-4.0 eq) were added. The mixture was then heated to 80-100°C and refluxed for 2-30 hours. The mixture was filtered with diatomaceous earth to remove salts and catalysts. Water and dichloromethane were added to the filtrate for separation and extraction. The organic phase was retained and concentrated. The solution was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V = 1:3-1:10) to obtain chemical formula I.

[0058] The specific synthesis route is as follows:

[0059] .

[0060] Among them, R, R1-R2, n1-n2, L, Ar1-Ar4 are as defined in chemical formula I, and Hal1-Hal3 are selected from Cl, Br, and I.

[0061] The present invention also provides an organic electroluminescent device, the organic electroluminescent device comprising an anode, a cathode and an organic material layer disposed between the anode and the cathode, the organic material layer containing the aforementioned material having electron transport function.

[0062] In one embodiment of the present invention, the organic electroluminescent device includes an anode, a cathode, and an organic material layer disposed between the anode and the cathode, wherein the organic material layer contains a hole blocking layer, and the hole blocking layer is the material having electron transport function.

[0063] In one embodiment of the present invention, the organic electroluminescent device includes an anode, a cathode, and an organic material layer disposed between the anode and the cathode, wherein the organic material layer contains an electron transport layer, and the electron transport layer is the material having electron transport function.

[0064] It should be noted that the organic material layer of the organic electroluminescent device in this invention can be formed as a single-layer structure or as a multilayer structure with two or more organic material layers.

[0065] For example, the organic electroluminescent device may have a structure comprising organic material layers such as a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting auxiliary layer, a light-emitting layer, a hole blocking layer, an electron transport layer, and an electron injection layer. However, the structure of the organic electroluminescent device is not limited to this, and may include fewer or more organic material layers.

[0066] A third objective of this invention is to provide an application of a material with electron transport functionality, as described above, in an organic electroluminescent device.

[0067] Furthermore, the organic electroluminescent device can be used in organic electroluminescent apparatuses, including but not limited to flat panel displays, computer monitors, a medical monitor, a television set, billboards, a lamp for internal or external lighting and / or signaling, head-up displays, fully transparent or partially transparent displays, flexible displays, a laser printer, a telephone, a mobile phone, tablets, a photo album, a personal digital assistant (PDA), a wearable device, a laptop computer, a digital camera, a camcorder, a viewfinder, a microdisplay, a 3D display, a virtual reality or augmented reality display, vehicles, video walls comprising multiple displays tiled together, theater or stadium screens, phototherapy devices, and signs.

[0068] Beneficial effects of the invention

[0069] This invention provides a compound material with electron transport function. This compound has good electron transport function characteristics, and organic electroluminescent devices prepared with it have low driving voltage, high luminous efficiency and long service life.

[0070] In the structure of the compound, 9-alkyl-9-phenylfluorene is one of the core structures. Fluorene itself is a relatively planar fused-ring aromatic hydrocarbon. The introduction of alkyl and phenyl groups at the 9-position generates strong steric repulsion with the fluorene ring itself, forming a three-dimensional, non-planar "propeller"-like structure. This non-planar structure can effectively suppress the close packing of molecules in the solid state, thereby preventing concentration quenching and excitopolymer formation caused by π-π packing, achieving higher solid-state luminescence efficiency. Furthermore, this rigid, non-planar structure can also effectively improve the thermal stability of the material and the lifespan of the device.

[0071] Furthermore, a phenanthrene group is attached to the benzene ring at position 9 of the fluorene group, connecting the overall structure of the fluorene side and the triazine group side. This bridging group effectively expands the conjugated system of the molecule, enhancing electron delocalization and electron hopping transport, thus significantly improving the luminous efficiency of the device. The large, rigid planar structure of the phenanthrene group also endows the material with a high glass transition temperature and thermal decomposition temperature, making the material less prone to decomposition during high-temperature evaporation and long-term operation, thereby extending the device's lifespan. Triazine is a strongly electron-deficient aromatic heterocycle, which forms the basis of the entire molecule's electron transport capability. It has high electron affinity and can effectively extract electrons from the excited state or electrode interface, making it a highly efficient electron acceptor. As the molecular core, triazine can significantly lower the lowest unoccupied molecular orbital (LUMO) energy level of the entire molecule. The low LUMO energy level makes it easier for electrons to be injected from the cathode into the electron transport layer, reducing the injection barrier. The rigid triazine ring also helps to increase the thermal decomposition temperature and glass transition temperature of the material, preventing crystallization or phase separation due to heat during device operation, thereby extending the device's lifespan.

[0072] The compound structure with electron transport function provided by this invention, with the connection of 9-alkyl-9-phenylfluorene, phenanthrene, and triazine, forms a strong D-π-A (donor-bridge-acceptor) system. The hole injection / transport capability of the fluorene group compensates for the defects of the triazine system, resulting in superior device performance. In particular, when compound materials with direct connection between the bridging phenanthrene group and the triazine side are applied to devices, the devices exhibit longer lifespans. To obtain a tunable and even better-performing structure, an L-group (phenyl, biphenyl, naphthyl) is further introduced between the phenanthrene and triazine groups. This effectively extends the conjugated system, significantly improves the electron mobility of the entire material, and helps the device achieve higher luminous efficiency.

[0073] Furthermore, structures with cyano-substituted phenyl, biphenyl, or pyridyl groups can be introduced onto the triazine group. Among these, the introduced cyano group is one of the strongest known electron-withdrawing groups. The cyano group and triazine work together; the introduction of the cyano group further lowers the LUMO energy level of the triazine and even the entire molecule, resulting in stronger electron injection and transport capabilities. This type of compound, as an electron transport layer material, further enhances the performance of its devices. Attached Figure Description

[0074] Figure 1 The image shows the 1H NMR spectrum of compound 1 prepared in Example 1.

[0075] Figure 2 The 1H NMR spectrum of compound 114 prepared in Example 2. Detailed Implementation

[0076] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0077] Additionally, it should be noted that the values ​​given in the following embodiments are as accurate as possible. However, those skilled in the art will understand that due to unavoidable measurement errors and experimental issues, each number should be understood as an approximation rather than an absolutely accurate value.

[0078] Example 1

[0079]

[0080] Step 1:

[0081] The mixture was cooled to -78℃, and raw material B-1 (1.2 eq, CAS No.: 108313-42-4) was dissolved in THF. Nitrogen gas was replaced three times, and the mixture was stirred for 30 min. Then, n-butyllithium (1.5 eq) was slowly added to the reaction flask, and the reaction was allowed to proceed for 2 h. Raw material A-1 (1.0 eq, CAS No.: 952573-40-9) was dissolved in tetrahydrofuran, and the solution of raw material A-1 was slowly added dropwise to the reaction flask. The mixture was stirred until homogeneous, and the refrigeration was stopped. The mixture was then heated to room temperature and the reaction was allowed to continue for 10 h. The reaction was detected by thin-layer chromatography. After the reaction was completed, the mixture was washed three times with water, and the organic phase was retained. The aqueous phase was then extracted with dichloromethane. The organic phases were combined and concentrated. The intermediate 1-1 (yield: 65.1%) was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V=1:2).

[0082] Step 2:

[0083] Intermediate 1 (1.0 eq) was dissolved in dichloromethane. Triethylsilane (1.5 eq) was added under stirring at -10°C. After stirring for 30 min, methanesulfonic acid (3.0 eq) was added, and stirring was continued for 15 min. The mixture was then transferred to room temperature and reacted for 2 h. The reaction was detected by thin-layer chromatography. After the reaction was completed, water was added to the reaction solution and stirred. The mixture was extracted and separated, and the organic phase was retained. The aqueous phase was then extracted with dichloromethane. The organic phases were combined and concentrated. The mixture was purified by column chromatography using petroleum ether to obtain intermediate 2-1 (yield: 72.9%).

[0084] Step 3:

[0085] Intermediate 2-1 (1.0 eq) was dissolved in THF and stirred at room temperature until dissolved. Then, t-BuOK (5.0 eq) was slowly added to the reaction flask and stirred for 1 h. Then, iodomethane (5.0 eq) was slowly added dropwise, and the temperature was raised to 80 °C and the reaction was carried out for 11 h. The reaction was detected by thin-layer chromatography. After the reaction was completed, the temperature was lowered slightly, and the mixture was filtered with diatomaceous earth to remove salt. Water and dichloromethane were added to the filtrate for separation and extraction. The organic phase was retained and concentrated. Intermediate 3-1 (yield: 66.3%) was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V=1:4).

[0086] Step 4:

[0087] Intermediate 3-1 (1.0 eq), pinacol diborate (1.5 eq), and potassium acetate (3.0 eq) were added to a reaction flask, followed by 1,4-dioxane. Nitrogen gas was introduced, and tris(dibenzylacetone)dipalladium (0.03 eq) and X-Phos (0.2 eq) were added under nitrogen protection. The mixture was then heated to 120 °C and refluxed for 13 h. The reaction was detected by thin-layer chromatography. After the reaction was completed, the temperature was slightly lowered, and the mixture was filtered with diatomaceous earth to remove salts and catalysts. Water and dichloromethane were added to the filtrate for separation and extraction. The organic phase was retained and concentrated. Intermediate 4-1 (yield: 77.9%) was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V=1:4).

[0088] Step 5:

[0089] Intermediate 4-1 (1.0 eq) and starting material D-1 (1.2 eq, CAS No.: 91960-73-5) were added to a reaction flask, followed by a mixed solution of toluene, ethanol and water (V:V:V = 3:1:1). Nitrogen gas was introduced, and tetrakis(triphenylphosphine)palladium (0.01 eq) and potassium carbonate (2.0 eq) were added under nitrogen protection. The mixture was then heated to 95 °C and refluxed for 8 h. The mixture was filtered with diatomaceous earth to remove salts and catalysts. Water and dichloromethane were added to the filtrate for separation and extraction. The organic phase was retained and concentrated. Intermediate 5-1 (yield: 82.3%) was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V = 1:6).

[0090] Step 6:

[0091] Intermediate 5-1 (1.0 eq), pinacol diborate (1.5 eq), and potassium acetate (3.0 eq) were added to a reaction flask, followed by 1,4-dioxane. Nitrogen gas was introduced, and tris(dibenzylacetone)dipalladium (0.03 eq) and X-Phos (0.2 eq) were added under nitrogen protection. The mixture was then heated to 120 °C and refluxed for 15 h. The reaction was detected by thin-layer chromatography. After the reaction was completed, the temperature was slightly lowered, and the mixture was filtered with diatomaceous earth to remove salts and catalysts. Water and dichloromethane were added to the filtrate for separation and extraction. The organic phase was retained and concentrated. Intermediate 6-1 (yield: 77.6%) was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V = 1:4).

[0092] Step 7:

[0093] Intermediate 6-1 (1.0 eq) and starting material E-1 (1.0 eq, CAS No.: 2606032-37-3) were added to a reaction flask, followed by a mixed solution of toluene, ethanol and water (V:V:V = 3:1:1). Nitrogen gas was introduced, and tetrakis(triphenylphosphine)palladium (0.04 eq) and potassium carbonate (4.0 eq) were added under nitrogen protection. The mixture was then heated to 95 °C and refluxed for 18 h. The mixture was filtered with diatomaceous earth to remove salts and catalysts. Water and dichloromethane were added to the filtrate for separation and extraction. The organic phase was retained and concentrated. Compound 1 was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V = 1:5) (yield: 84.5%).

[0094] The obtained compound 1 was analyzed, and the results are as follows:

[0095] HPLC purity: >99.8%.

[0096] Mass spectrometry test: Waters XEVO TQD mass spectrometer with ESI source.

[0097] Test value MS(ESI, m / Z): [M+H] + =740.38.

[0098] Elemental analysis:

[0099] The test values ​​are: C, 89.06; H, 5.16; N, 5.83.

[0100] Nuclear magnetic resonance hydrogen spectrum: as shown Figure 1 As shown in (Compound 1).

[0101] Example 2

[0102]

[0103] Step 1:

[0104] The mixture was cooled to -78℃, and raw material B-114 (1.2 eq, CAS No.: 108313-42-4) was dissolved in THF. Nitrogen gas was replaced three times, and the mixture was stirred for 30 min. Then, n-butyllithium (1.5 eq) was slowly added to the reaction flask, and the reaction was allowed to proceed for 2 h. Raw material A-114 (1.0 eq, CAS No.: 4269-14-1) was dissolved in tetrahydrofuran, and the solution of raw material A-114 was slowly added dropwise to the reaction flask. The mixture was stirred until homogeneous, and the refrigeration was stopped. The mixture was then heated to room temperature and the reaction was allowed to continue for 12 h. The reaction was detected by thin-layer chromatography. After the reaction was completed, the mixture was washed three times with water, and the organic phase was retained. The aqueous phase was then extracted with dichloromethane. The organic phases were combined and concentrated. The intermediate 1-114 (yield: 64.8%) was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V=1:2).

[0105] Step 2:

[0106] Intermediate 1-114 (1.0 eq) was dissolved in dichloromethane. Triethylsilane (1.5 eq) was added under stirring at -10°C. After stirring for 30 min, methanesulfonic acid (3.0 eq) was added, and stirring was continued for 15 min. The mixture was then transferred to room temperature and reacted for 2 h. The reaction was detected by thin-layer chromatography. After the reaction was completed, water was added to the reaction solution and stirred. The mixture was extracted and separated, and the organic phase was retained. The aqueous phase was then extracted with dichloromethane. The organic phases were combined and concentrated. Intermediate 2-114 was purified by column chromatography using petroleum ether (yield: 72.5%).

[0107] Step 3:

[0108] Intermediate 2-114 (1.0 eq) was dissolved in THF and stirred at room temperature until dissolved. Then, t-BuOK (5.0 eq) was slowly added to the reaction flask and stirred for 1 h. Then, iodomethane (5.0 eq) was slowly added dropwise, and the temperature was raised to 80 °C and reacted for 12 h. The reaction was detected by thin-layer chromatography. After the reaction was completed, the temperature was lowered slightly, and the mixture was filtered with diatomaceous earth to remove salt. Water and dichloromethane were added to the filtrate for separation and extraction. The organic phase was retained and concentrated. Intermediate 3-114 (yield: 66.1%) was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V=1:5).

[0109] Step 4:

[0110] Intermediate 3-114 (1.0 eq), pinacol diborate (1.5 eq), and potassium acetate (3.0 eq) were added to a reaction flask, followed by 1,4-dioxane. Nitrogen gas was introduced, and under nitrogen protection, tris(dibenzylacetone)dipalladium (0.03 eq) and X-Phos (0.2 eq) were added. The mixture was then heated to 120 °C and refluxed for 14 h. The reaction was detected by thin-layer chromatography. After the reaction was completed, the temperature was slightly lowered, and the mixture was filtered with diatomaceous earth to remove salts and catalysts. Water and dichloromethane were added to the filtrate for separation and extraction. The organic phase was retained and concentrated. Intermediate 4-114 (yield: 77.4%) was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V = 1:4).

[0111] Step 5:

[0112] Intermediate 4-114 (1.0 eq) and starting material D-114 (1.2 eq, CAS No.: 91960-73-5) were added to a reaction flask, followed by the addition of a mixed solution of toluene, ethanol, and water (V:V:V = 3:1:1). Nitrogen gas was introduced, and tetrakis(triphenylphosphine)palladium (0.01 eq) and potassium carbonate (2.0 eq) were added under nitrogen protection. The mixture was then heated to 95 °C and refluxed for 8 h. The mixture was filtered with diatomaceous earth to remove salts and catalysts. Water and dichloromethane were added to the filtrate for separation and extraction. The organic phase was retained and concentrated. Intermediate 5-114 (yield: 82.0%) was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V = 1:6).

[0113] Step 6:

[0114] Intermediate 5-114 (1.0 eq), pinacol diborate (1.5 eq), and potassium acetate (3.0 eq) were added to a reaction flask, followed by 1,4-dioxane. Nitrogen gas was introduced, and under nitrogen protection, tris(dibenzylacetone)dipalladium (0.03 eq) and X-Phos (0.2 eq) were added. The mixture was then heated to 120 °C and refluxed for 16 h. The reaction was detected by thin-layer chromatography. After the reaction was completed, the temperature was slightly lowered, and the mixture was filtered with diatomaceous earth to remove salts and catalysts. Water and dichloromethane were added to the filtrate for separation and extraction. The organic phase was retained and concentrated. Intermediate 6-114 (yield: 77.1%) was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V = 1:4).

[0115] Step 7:

[0116] Intermediate 6-114 (1.0 eq) and starting material E-114 (1.0 eq, CAS No.: 3842-55-5) were added to a reaction flask, followed by a mixed solution of toluene, ethanol, and water (V:V:V = 3:1:1). Nitrogen gas was introduced, and palladium acetate (0.05 eq), X-Phos (0.3 eq), and cesium carbonate (4.0 eq) were added under nitrogen protection. The mixture was then heated to 95 °C and refluxed for 20 h. The mixture was filtered with diatomaceous earth to remove salts and catalysts. Water and dichloromethane were added to the filtrate for separation and extraction. The organic phase was retained and concentrated. Compound 114 (yield: 84.2%) was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V = 1:5).

[0117] The obtained compound 114 was analyzed, and the results are as follows:

[0118] HPLC purity: >99.7%.

[0119] Mass spectrometry test: Waters XEVO TQD mass spectrometer with ESI source.

[0120] Test value MS(ESI, m / Z): [M+H] + =740.41.

[0121] Elemental analysis:

[0122] The test values ​​are: C, 89.04; H, 5.18; N, 5.85.

[0123] Nuclear magnetic resonance hydrogen spectrum: as shown Figure 2 As shown in (Compound 114).

[0124] In addition, it should be noted that other compounds of the present invention can be obtained by referring to the preparation methods of the examples listed above, so they will not be listed one by one here.

[0125] Device Application Example 1

[0126] Fabrication of organic electroluminescent devices

[0127] The structure of the fabricated OLED device is: ITO anode / HIL / HTL / Prime / EML / HBL / ETL / EIL / cathode / light extraction layer.

[0128] a. ITO anode: The ITO (indium tin oxide)-Ag-ITO (indium tin oxide) glass substrate with a coating thickness of 1500 angstroms was cleaned three times in distilled water and ultrasonically washed for 30 minutes. Then it was cleaned three times in distilled water and ultrasonically washed for 10 minutes. After washing, it was ultrasonically washed sequentially with methanol, acetone and isopropanol (5 minutes each time). After drying, it was transferred to a plasma cleaner for 5 minutes and then sent to a vapor deposition machine. Using this substrate as the anode, other functional layers were sequentially vapor deposited on it.

[0129] b. HIL (Hole Injection Layer): Hole injection layer materials HT and P-dopant are vacuum-deposited at a deposition rate of 1 Å / s. The chemical formulas are shown below. The deposition rate ratio of HT to P-dopant is 97:3, and the thickness is 10 nm.

[0130] c. HTL (Hole Transport Layer): A 130nm HT layer is vacuum-deposited on top of the hole injection layer at a deposition rate of 1.5 Å / s as the hole transport layer.

[0131] d. Prime (light-emitting auxiliary layer): A 5nm Prime layer is vacuum-deposited on the hole transport layer at a deposition rate of 0.5 Å / s as a light-emitting auxiliary layer.

[0132] e. EML (Emitting Layer): A host material and a dopant material with a thickness of 30 nm are vacuum-deposited on the emitting auxiliary layer at a deposition rate of 1 Å / s. The chemical formulas of the host and the dopant are shown below, and the deposition rate ratio of the host to the dopant is 97:3.

[0133] f. HBL (hole blocking layer): Compound 1 with a thickness of 5 nm was vacuum-deposited on the light-emitting layer at a deposition rate of 0.5 Å / s as a hole blocking layer.

[0134] g. ETL (Electron Transport Layer): ET and Liq with a thickness of 30 nm are vacuum-deposited on the hole blocking layer at a deposition rate of 1 Å / s, with the deposition rate ratio of ET to Liq being 50:50.

[0135] h. EIL (Electron Injection Layer): A Yb film with a thickness of 1 nm is vacuum-deposited on the electron transport layer at a deposition rate of 0.5 Å / s to form the electron injection layer.

[0136] i. Cathode: Magnesium and silver with a thickness of 13 nm are vacuum-deposited on the electron injection layer at a deposition rate of 1 Å / s, with a deposition rate ratio of 1:9 for magnesium and silver, to obtain the cathode.

[0137] j. Optical extraction layer: A CPL with a thickness of 70 nm is vacuum-deposited on the cathode at a deposition rate of 1 Å / s as the optical extraction layer.

[0138] K. Encapsulate the vapor-deposited substrate: First, use a coating equipment to coat the cleaned cover plate with UV adhesive. Then, move the coated cover plate to the lamination section, place the vapor-deposited substrate on the top of the cover plate, and finally, laminate the substrate and cover plate together under the action of the lamination equipment, while simultaneously curing the UV adhesive by light.

[0139] The required material structure is shown below:

[0140] .

[0141] Device Application Example 2-191

[0142] Referring to the method provided in Device Application Example 1 above, the corresponding compounds in Table 1 below were selected to replace compound 1, hole blocking layers were deposited, and corresponding organic electroluminescent devices were prepared, which are respectively referred to as Device Application Example 2-191.

[0143] Device Comparison Examples 1-15

[0144] The device comparative example was prepared according to the method provided in Device Application Example 1 above, except that the hole blocking layer (compound 1) in Device Application Example 1 was replaced with the existing comparative compound ao, wherein the structural formula of compound ao is as follows:

[0145] .

[0146] The driving voltage, BI value, and lifetime of the organic electroluminescent devices obtained by the above-mentioned devices in Examples 1 to 191 and Comparative Examples 1 to 15 were characterized at a brightness of 1000 nits. The test results are shown in Table 1 below.

[0147] Table 1 Device Test Results

[0148]

[0149]

[0150]

[0151]

[0152]

[0153] Device Application Example 192:

[0154] Fabrication of organic electroluminescent devices

[0155] The structure of the fabricated OLED device is: ITO anode / HIL / HTL / Prime / EML / HBL / ETL / EIL / cathode / light extraction layer.

[0156] a. ITO anode: The ITO (indium tin oxide)-Ag-ITO (indium tin oxide) glass substrate with a coating thickness of 1500 angstroms was cleaned three times in distilled water and ultrasonically washed for 30 minutes. Then it was cleaned three times in distilled water and ultrasonically washed for 10 minutes. After washing, it was ultrasonically washed sequentially with methanol, acetone and isopropanol (5 minutes each time). After drying, it was transferred to a plasma cleaner for 5 minutes and then sent to a vapor deposition machine. Using this substrate as the anode, other functional layers were sequentially vapor deposited on it.

[0157] b. HIL (Hole Injection Layer): Hole injection layer materials HT and P-dopant are vacuum-deposited at a deposition rate of 1 Å / s. The chemical formulas are shown below. The deposition rate ratio of HT to P-dopant is 97:3, and the thickness is 10 nm.

[0158] c. HTL (Hole Transport Layer): A 130nm HT layer is vacuum-deposited on top of the hole injection layer at a deposition rate of 1.5 Å / s as the hole transport layer.

[0159] d. Prime (light-emitting auxiliary layer): A 5nm Prime is vacuum-deposited on the hole transport layer at a deposition rate of 0.5 Å / s as a light-emitting auxiliary layer.

[0160] e. EML (Emitting Layer): A host material and a dopant material with a thickness of 30 nm are vacuum-deposited on the emitting auxiliary layer at a deposition rate of 1 Å / s. The chemical formulas of the host and the dopant are shown below, and the deposition rate ratio of the host to the dopant is 97:3.

[0161] f. HBL (hole blocking layer): A 5nm thick HB layer is vacuum-deposited on the light-emitting layer at a deposition rate of 0.5 Å / s as a hole blocking layer.

[0162] g. ETL (Electron Transport Layer): Compound 405 and Liq with a thickness of 30 nm are vacuum-deposited on the hole blocking layer at a deposition rate of 1 Å / s, wherein the deposition rate ratio of compound 405 and Liq is 50:50.

[0163] h. EIL (Electron Injection Layer): A Yb film with a thickness of 1 nm is vacuum-deposited on the electron transport layer at a deposition rate of 0.5 Å / s to form the electron injection layer.

[0164] i. Cathode: Magnesium and silver with a thickness of 13 nm are vacuum-deposited on the electron injection layer at a deposition rate of 1 Å / s, with a deposition rate ratio of 1:9 for magnesium and silver, to obtain the cathode.

[0165] j. Optical extraction layer: A CPL with a thickness of 70 nm is vacuum-deposited on the cathode at a deposition rate of 1 Å / s as the optical extraction layer.

[0166] K. Encapsulate the vapor-deposited substrate: First, use a coating equipment to coat the cleaned cover plate with UV adhesive. Then, move the coated cover plate to the lamination section, place the vapor-deposited substrate on the top of the cover plate, and finally, laminate the substrate and cover plate together under the action of the lamination equipment, while simultaneously curing the UV adhesive by light.

[0167] The required material structure is shown below:

[0168] .

[0169] Device Application Examples 193-278

[0170] Referring to the method provided in Device Application Example 192 above, the corresponding compounds in Table 2 below were selected to replace compound 405, and the electron transport layer was deposited to prepare the corresponding organic electroluminescent devices, which are respectively referred to as Device Application Examples 193-278.

[0171] Device Comparison Examples 16-17

[0172] A comparative device was prepared according to the method provided in Device Application Example 192 above, except that the electron transport layer (compound 405) in Device Application Example 192 was replaced with the existing comparative compound pq, wherein the structural formula of compound pq is as follows:

[0173] .

[0174] The driving voltage, BI value, and lifetime of the organic electroluminescent devices obtained by the above-mentioned device application examples 192-278 and device comparative examples 16-17 were characterized at a brightness of 1000 nits. The test results are shown in Table 2 below.

[0175] Table 2 Device Test Results

[0176]

[0177]

[0178]

[0179] In blue top-emitting devices, luminous efficiency is greatly affected by chromaticity. Therefore, the influence of chromaticity on efficiency is taken into account, and the ratio of luminous efficiency to CIEy is defined as the BI value, i.e., BI = (cd / A) / CIEy. In the test, the CIEy value was adjusted to be between 0.044 and 0.046.

[0180] As can be seen from Tables 1 and 2, compared with devices prepared using comparative compounds, organic electroluminescent devices prepared using the electron transport function provided by this invention exhibit superior device performance, with characteristics of low driving voltage, high luminous efficiency, and long lifetime.

[0181] Comparative compounds a, b, and c are parallel comparative examples to compounds 188, 200, and 160 of this invention. The difference lies in the structure: in the compounds of this invention, a 9-alkyl-9-phenylfluorene is attached to a phenanthrene group, while in the structures of comparative compounds a, b, and c, 9,9-diphenyl-benzofluorene, spirodifluorene, and 9,9-diphenylfluorene are attached, respectively. The increased molecular weight leads to a higher evaporation temperature. Excessively high evaporation temperatures increase the tendency for thermal decomposition of the material during device fabrication, affecting the device's lifespan.

[0182] Comparative examples of compounds dj and p with compounds 34, 200, 2, 28, 114, 317, 226, and 446 of this invention are parallel comparative examples. The difference lies in the fact that the compounds of this invention contain a phenanthrene group in the middle of the structure, which connects the phenyl group at position 9 of the fluorene group to the overall structure on one side of the triazine group. The phenanthrene group is a large planar fused-ring aromatic hydrocarbon, which significantly expands the conjugated system of the molecule. Electrons can be delocalized in a larger π system, which is beneficial for electron hopping and transport, and effectively improves the luminous efficiency of the device. The large rigid planar structure of the phenanthrene group endows the material with a high glass transition temperature and thermal decomposition temperature, making the material less prone to decomposition during high-temperature evaporation and long-term operation, thus extending the service life of the device.

[0183] The comparison compound ko is a parallel comparative example with compounds 114, 44, 251, 66, and 44 of this invention. The difference lies in the structure of the compounds of this invention: the phenanthrene group at the end of the compound is connected to a 9-alkyl-9-phenylfluorene group, and the connection position is on the phenyl group at position 9. Fluorene itself has a wide band gap and high three-mode energy levels. The introduction of alkyl and phenyl groups at position 9 can enhance steric hindrance, prevent overly tight π-π stacking between molecules, thereby reducing concentration quenching and improving fluorescence quantum yield. The steric structure of this fluorene group can also enhance the stability of the material and directly improve the lifespan of the device. Furthermore, the addition of 9-alkyl-9-phenyl groups, along with the connection of the phenanthrene group and triazine, forms a more robust D-π-A (donor-bridge-acceptor) system. The hole injection / transport capability of the fluorene group compensates for the defects of the triazine system, resulting in more balanced device performance.

[0184] As can be seen from the above, the compound structure of the present invention has good thermal stability and can be used as an electron transport layer and hole blocking layer in organic electroluminescent devices. The prepared devices have excellent performance with low driving voltage, high luminous efficiency and long service life.

[0185] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A material with electron transport function, characterized in that, It has the structure shown in chemical formula I: ； in, R is independently selected from substituted or unsubstituted methyl, substituted or unsubstituted ethyl, substituted or unsubstituted propyl, substituted or unsubstituted isopropyl, substituted or unsubstituted tert-butyl; R1 and R2 are independently selected from hydrogen and deuterium, respectively; L is independently selected from the linking bond, substituted or unsubstituted phenyl, substituted or unsubstituted biphenyl, substituted or unsubstituted naphthyl; n1 is independently selected from 0, 1, 2, 3, 4, 5, 6, 7, 8; n2 is independently selected from 0, 1, 2, 3, and 4; Ar1 and Ar2 are each independently selected from the following structures: In the above substituents, any H can be independently substituted by deuterium; Ar3 and Ar4 are independently selected from hydrogen, deuterium, and the following structures: In the above substituents, any H can be independently substituted by deuterium; Indicates the linkage site of the functional group; In the chemical formula I, any hydrogen atom can be independently replaced by deuterium; The term "substituted or unsubstituted" means substituted by one, two or more substituents selected from the following: deuterium, cyano, halogen, methyl, ethyl, propyl, butyl, tert-butyl, cyclopentane, cyclohexane, phenyl, biphenyl, naphthyl, fluorenyl, dimethylfluorenyl, phenanthrene, triphenylene, carbazolyl, furanyl, thiophene, pyrrole, pyridyl, benzofuranyl, benzothiophene, isobenzofuranyl, dibenzofuranyl, dibenzothiophene, or substituted by two or more substituents linked together from the substituents shown above, or without substituents.

2. The material with electronic transmission function according to claim 1, characterized in that, Chemical formula I has the following structures: IA~IF: Among them, R3-R 11 They are each independently selected from hydrogen and deuterium; n3, n4, n5, n 11 Each of the numbers 0, 1, 2, 3, and 4 is selected independently. n6, n8, and n9 are independently selected from 0, 1, 2, and 3, respectively; n7 is independently selected from 0, 1, 2, 3, 4, and 5; n 10 Selected independently from 0, 1, and 2.

3. The material with electronic transmission function according to claim 1, characterized in that, Chemical formula I has any one of the structures of compounds 1-568: 。 4. An organic electroluminescent device, characterized in that, The organic electroluminescent device includes an anode, a cathode, and an organic material layer disposed between the anode and the cathode. The organic material layer contains an electron transport layer and / or a hole blocking layer, wherein the electron transport layer and / or hole blocking layer is a material with electron transport function as described in any one of claims 1 to 3.

5. The application of the organic electroluminescent device as described in claim 4 in an organic electroluminescent apparatus.

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