A luminescent auxiliary material, a preparation method thereof, and an organic electroluminescent device containing the same

Abstract

The present application belongs to the field of organic photoelectric materials, and provides a kind of luminescent auxiliary material and its preparation method and organic electroluminescent device containing the same. On the one hand, the present application limits the molecular weight of the compound to a reasonable number of atoms on the basis of introducing 9-alkyl-9-phenyl-fluorene groups into triarylamine molecules as hole transport functional groups, thereby balancing the molecular weight of the overall molecule and regulating the evaporation temperature so that it is not too high and affects the device life; on the other hand, the migration rate of the compound is improved by introducing dibenzofuran, and after being used in the device, the hole transport energy barrier can be reduced and the luminous efficiency can be improved; and the present invention extends the compound conjugated system by introducing different substituents of Ar or changing different connection positions, thereby achieving the regulation of different photoelectric properties and thermal properties.

Description

Technical Field

[0001] The present application belongs to the technical field of organic optoelectronic materials, and in particular relates to a luminescent auxiliary material, a preparation method thereof, and an organic electroluminescent device containing the same. Background Art

[0002] Organic luminescence refers to the phenomenon of converting electrical energy into light energy using organic substances. Organic light-emitting devices using organic luminescence have wide viewing angles, excellent contrast, fast response time, and excellent brightness, driving voltage and response speed characteristics. Therefore, a lot of research is currently underway.

[0003] In organic electroluminescent devices, charges injected from two electrodes recombine in the light-emitting layer to produce light. Efficient charge transfer of holes and electrons to the light-emitting layer is crucial, and the device must possess an excellent carrier balance. Furthermore, luminescence efficiency is improved by enhancing hole injection and electron blocking properties to block electrons injected from the cathode, thereby increasing the probability of hole-electron recombination, and by confining excitons generated within the light-emitting layer. Therefore, luminescence-assisting materials play a crucial role.

[0004] Research on organic electroluminescent materials has been extensively conducted in academia and industry, but stable and efficient organic layer materials for organic electrical devices have yet to be fully developed. Furthermore, the industrialization of this technology still faces many key challenges, such as high driving voltage, low luminous efficiency, and short lifespan in the resulting devices. Therefore, the development of new materials has always been a pressing issue for those skilled in the art. Summary of the Invention

[0005] The purpose of the present application is to provide a luminescence auxiliary material, so that the device obtained by applying the material to an organic electroluminescent device has the technical effects of low driving voltage, high luminescence efficiency, and / or long service life.

[0006] The first technical purpose of the present invention is to provide a luminescence auxiliary material, the general structural formula of which is shown in Chemical Formula I:

[0007]

[0008] In the chemical formula I:

[0009] R1, R2, and R3 may be the same or different, and each independently represents a substituted or unsubstituted C6-C30 aryl group or a substituted or unsubstituted C6-C30 heteroaryl group, wherein the heteroatom is at least one of O, S, N, Si, and Se;

[0010] Ar is independently selected from the following groups:

[0011]

[0012] wherein R4 is selected from hydrogen, deuterium, substituted or unsubstituted C1-C5 alkyl, substituted or unsubstituted C6-C12 aryl, substituted or unsubstituted C6-C12 heteroaryl, and its heteroatom is at least one of O, S, N, Si, and Se;

[0013] R5 is selected from a substituted or unsubstituted C6-C12 aryl group, or a substituted or unsubstituted C6-C12 heteroaryl group, wherein the heteroatom is at least one of O, S, N, Si, and Se; m can be an integer of 0 or 1; s and t are integers selected from 0 or 1, and s and t cannot be both 0;

[0014] Furthermore, R1, R2, and R3 may be the same or different, and independently represent phenyl, biphenyl, and naphthyl;

[0015] R4 is selected from hydrogen, methyl, phenyl, naphthyl, biphenyl; R5 is selected from phenyl, naphthyl, biphenyl.

[0016] Then the above chemical formula I is further preferably a general structural formula:

[0017]

[0018] In the above Chemical Formula-I-1 and Chemical Formula-I-2, R1, R2, R3, m, and Ar are as defined above, and s and t are integers of 1.

[0019] In the present specification, "substituted" means substituted by one, two or more substituents selected from the group consisting of hydrogen, deuterium, a halogen group, a cyano group, a trifluoromethyl group, a methyl group, an ethyl group, a propyl group, an n-propyl group, an isopropyl group, a butyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a sec-butyl group, a 1-methylbutyl group, a 1-ethylbutyl group, a pentyl group, an n-pentyl group, an isopentyl group, a neopentyl group, a tert-pentyl group, a hexyl group, an n-hexyl group, a 1-methylpentyl group, a 2-methylpentyl group, a 4-methyl-2-pentyl group, a 3,3-dimethylbutyl group, a 2-ethylbutyl group, a 1-methylhexyl group, a phenyl group, a naphthyl group, an anthracenyl group, a phenanthrenyl group, a thienyl group, a furyl group, a pyrrolyl group, a benzothienyl group, a benzofuranyl group, a pyridyl group, an indolyl group, a cyclopentyl group, a cyclohexyl group, and an adamantane group.

[0020] In the above technical solution, it is further preferred that the light-emitting auxiliary material is any one of the following structures, but not limited thereto:

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[0073] The second technical purpose of this application is to provide a method for preparing the luminescence auxiliary material. Synthesis route:

[0074]

[0075] In the above formula, R1, R2, R3, m, s, t, and Ar are as defined in the above chemical formula I, and Hal is independently selected from chlorine, bromine, or iodine.

[0076] It is worth noting that, with respect to complex raw materials that are not disclosed, the classic Suzuki coupling reaction and / or Buchwald–Hartwig coupling reaction will be used for synthesis and applied in this application. The specific preparation steps are as follows:

[0077] Step 1, preparation of intermediate 1

[0078] The raw material A (1.0 eq) was dissolved in a mixed solution of toluene, ethanol and water, and the raw material B (1.2 eq) was dissolved in a mixed solution of toluene, ethanol and water, and then the raw material B solution was slowly added to the raw material A solution; then the mixture was ventilated three times, potassium carbonate (3.0 eq) and tetrakis(triphenylphosphine)palladium (0.01 eq) were added under nitrogen protection, stirred evenly, heated to 80°C-120°C, and refluxed for 4-12 hours; the reaction was detected by thin layer chromatography. After the reaction was completed, the temperature was slightly lowered, and the mixture was filtered using diatomaceous earth to remove salt and catalyst. After the filtrate was cooled to room temperature, it was washed with water three times, the organic phase was retained, and the aqueous phase was extracted with ethyl acetate; the organic phases were combined and concentrated, and purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V dichloromethane:V petroleum ether=1:3) to obtain intermediate 1;

[0079] Note: In this reaction step, the raw material A contains three halogens. On the one hand, the reaction activity of I>Br>Cl in the Suzuki coupling reaction is utilized. On the other hand, the reaction site is controlled by controlling the reaction conditions to achieve the preparation of the target structure intermediate. The reaction is purified by column chromatography or silica gel funnel to remove by-products and obtain the target compound. The reaction mechanism is shown in:

[0080] "Transition Metal Organic Chemistry" (Original Sixth Edition), Robert H. Crabtree, Publisher: Shanghai East China University of Science and Technology Press, Publication Date: 2017-09-00, ISBN: 978-7-5628-5111-0, Page 388.

[0081] Organic Chemistry and Photoelectric Materials Experimental Tutorial, Chen Runfeng, Southeast University Press, 2019-11-00, ISBN: 9787564184230, page 174.

[0082] Step 2, preparation of intermediate 2

[0083] The temperature was lowered to -78°C, and the intermediate 1 (1.2 eq) was dissolved in a tetrahydrofuran solution, ventilated 3 times, and stirred for 10 minutes. n-Butyl lithium (1.2 eq) was slowly added to the solution of intermediate 1. After reacting for 2 hours, the raw material C was slowly added dropwise to the reaction flask, stirred evenly, and the refrigeration was stopped. The temperature was raised to room temperature and the reaction was continued for 4-12 hours. The reaction was detected by thin layer chromatography. After the reaction was completed, the mixture was washed with water three times, and the organic phase was retained. The aqueous phase was then extracted with ethyl acetate. The organic phases were combined and concentrated, and purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V dichloromethane:V petroleum ether = 1:2) to obtain intermediate 2.

[0084] Step 3, preparation of intermediate 3

[0085] Intermediate 2 (1.0 eq) was dissolved in DCM and stirred at room temperature until dissolved. Boron trifluoride etherate (5.0 eq) was then added to the solution of Intermediate 2, stirred evenly, and reacted for 0.2-2 h. The reaction was monitored 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 ethyl acetate. The organic phases were combined and dried over anhydrous magnesium sulfate, and the solvent was removed using a rotary evaporator. A small amount of dichloromethane was used to completely dissolve the solid organic matter, which was then slowly added dropwise to a petroleum ether solution and stirred evenly. A precipitate was precipitated, which was filtered to obtain a solid, which was then rinsed with anhydrous ethanol and petroleum ether, and dried to obtain Intermediate 3.

[0086] Step 4, preparation of intermediate 4

[0087] Intermediate 3 (1.0 eq) was dissolved in THF and stirred at room temperature until dissolved. t-BuOK (5.0 eq) was then slowly added to the reaction flask. After stirring for one hour, CH3I (5.0 eq) was slowly added dropwise. The temperature was raised to 70-90°C and the reaction was carried out for 8-12 hours. The reaction was detected by thin layer chromatography. After the reaction was completed, the temperature was slightly lowered and filtered through diatomaceous earth to remove salt. The filtrate was cooled to room temperature and washed three times with water. The organic phase was retained and the aqueous phase was extracted with ethyl acetate. The organic phases were combined and dried over anhydrous magnesium sulfate, and the solvent was removed using a rotary evaporator. A small amount of dichloromethane was used to completely dissolve the solid organic matter, which was then slowly added dropwise to a petroleum ether solution and stirred evenly. A precipitate was precipitated and filtered to obtain a solid. The solid was washed with anhydrous ethanol and petroleum ether in sequence and dried to obtain intermediate 4.

[0088] Step 5, preparation of intermediate 5

[0089] Intermediate 4 (1.0 eq) was dissolved in toluene, and raw material E (1.2 eq) was dissolved in toluene, and then the raw material E solution was slowly added to the intermediate 4 solution. Then, the mixture was ventilated three times, and tris(dibenzylideneacetone)dipalladium (0.01-0.02 eq), tri-tert-butylphosphine (0.05 eq) and sodium tert-butoxide (2.0 eq) were added under nitrogen protection, stirred evenly, and the temperature was raised to 100°C-120°C for 1-4 hours. The reaction was detected by thin layer chromatography. After the reaction was completed, the temperature was slightly lowered and filtered using diatomaceous earth to remove salts and catalysts. After the filtrate was cooled to room temperature, it was washed with water three times, and the organic phase was retained. The aqueous phase was then extracted with ethyl acetate. The organic phases were combined and concentrated, and the mixture was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V dichloromethane:V petroleum ether = 1:5) to obtain intermediate 5.

[0090] Step 6, preparation of chemical formula I

[0091] Intermediate 5 (1.0 eq) was dissolved in toluene, and raw material F (1.1 eq) was dissolved in toluene, and then the raw material F solution was slowly added to the intermediate 5 solution. Then, the mixture was ventilated three times, and tris(dibenzylideneacetone)dipalladium (0.01-0.02 eq), tri-tert-butylphosphine (0.05 eq) and sodium tert-butoxide (2.0 eq) were added under nitrogen protection, stirred evenly, heated to 110°C-120°C, and reacted for 8-12 hours; the reaction was detected by thin layer chromatography. After the reaction was completed, the temperature was slightly lowered, and the mixture was filtered using diatomaceous earth to remove salts and catalysts. After the filtrate was cooled to room temperature, it was washed three times with water, the organic phase was retained, and the aqueous phase was extracted with ethyl acetate; after the organic phases were combined, they were dried over anhydrous magnesium sulfate, and the solvent was removed using a rotary evaporator; the mixture was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V dichloromethane:V petroleum ether = 1:8) to obtain chemical formula I.

[0092] A third technical objective of the present application is to provide an organic electroluminescent device, which includes the above-mentioned luminescence auxiliary material.

[0093] Furthermore, the organic electroluminescent device includes a luminescence auxiliary layer; the luminescence auxiliary layer includes the above-mentioned luminescence auxiliary material.

[0094] A fourth technical objective of the present application is to provide an organic light-emitting device, which includes the above-mentioned organic electroluminescent device.

[0095] The luminescent auxiliary material provided in the present application, on the one hand, limits the molecular weight of the compound to a reasonable atomic number on the basis of introducing a 9-alkyl-9-phenyl-fluorene group into the triarylamine molecule as a hole transport functional group, thereby balancing the molecular weight of the entire molecule and regulating the evaporation temperature so that it is not too high and affects the life of the device; on the other hand, the migration rate of the compound is improved by introducing dibenzofuran, and after being used in the device, the hole transport energy barrier can be reduced and the luminous efficiency can be improved; and the present invention extends the conjugated system of the compound by introducing different Ar substituents or changing different connection positions, thereby achieving the adjustment of different photoelectric properties and thermal properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0096] Figure 1 is the hydrogen nuclear magnetic resonance spectrum of compound 1 provided in Example 1 of the present application;

[0097] Figure 2 This is the hydrogen nuclear magnetic resonance spectrum of compound 315 provided in Example 3 of the present application. DETAILED DESCRIPTION

[0098] The present application provides a luminescence auxiliary material, a preparation method thereof, and an organic electroluminescent device containing the same.

[0099] The technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the luminescent auxiliary materials of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments.

[0100] Example 1: Preparation of Compound 1

[0101] Intermediate 4 in Example 1 is a prior art product (CAS No.: 2842863-92-5).

[0102]

[0103] Intermediate 4 (1.0 eq) was dissolved in toluene, and the raw material E-1 (1.2 eq) (CAS No.: 1795019-74-7) was dissolved in toluene. The raw material E-1 solution was then slowly added to the intermediate 4 solution. The mixture was then ventilated three times, and tris(dibenzylideneacetone)dipalladium (0.02 eq), tri-tert-butylphosphine (0.05 eq) and sodium tert-butoxide (2.0 eq) were added under nitrogen protection. The mixture was stirred evenly, heated to 110°C, and reacted for 4 hours. After the reaction, the temperature was slightly lowered, and the mixture was filtered through diatomaceous earth to remove salts and the catalyst. The filtrate was cooled to room temperature and washed three times with water. The organic phase was retained, and the aqueous phase was extracted with ethyl acetate. The organic phases were combined and concentrated, and purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V dichloromethane:V petroleum ether = 1:5) to obtain intermediate 5 (yield: 80.6%).

[0104] Intermediate 5 (1.0 eq) was dissolved in toluene, and raw material F-1 (1.1 eq) (CAS No.: 1822310-20-2) was dissolved in toluene, and then the raw material F-1 solution was slowly added to the intermediate 5 solution. Then, the mixture was ventilated three times, and tris(dibenzylideneacetone)dipalladium (0.01eq), tri-tert-butylphosphine (0.05eq) and sodium tert-butoxide (2.0eq) were added under nitrogen protection, stirred evenly, heated to 110°C, and reacted for 10h; the reaction was detected by thin layer chromatography. After the reaction was completed, the temperature was slightly lowered, and the mixture was filtered using diatomaceous earth to remove salt and catalyst. The filtrate was cooled to room temperature and washed three times with water, retaining the organic phase, and then the aqueous phase was extracted with ethyl acetate; after the organic phases were combined, they were dried over anhydrous magnesium sulfate, and the solvent was removed using a rotary evaporator; compound 1 was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V dichloromethane: V petroleum ether = 1:8) to obtain compound 1 (yield: 85.2%).

[0105] The obtained compound 1 was tested and analyzed, and the results were as follows:

[0106] HPLC purity: >99.8%.

[0107] Mass spectrometry test (mass spectrometry was performed using an ultra-high performance liquid chromatography-mass spectrometer and an ESI source, the same below): the test value was 751.4.

[0108] Elemental analysis:

[0109] Calculated values: C, 90.66; H, 5.30; N, 1.89; O, 2.16.

[0110] The test values are: C, 90.38; H, 5.48; N, 2.08; O, 2.35.

[0111] H NMR spectrum: Figure 1 shown.

[0112] Example 2: Preparation of Compound 177

[0113] Intermediate 4 in Example 2 is a prior art (CAS No.: 2331184-24-6)

[0114]

[0115] Intermediate 4 (1.0 eq) was dissolved in toluene, and the raw material E-177 (1.2 eq) (CAS No.: 134-32-7) was dissolved in toluene. The raw material E-177 solution was then slowly added to the intermediate 4 solution. The mixture was then ventilated three times, and tris(dibenzylideneacetone)dipalladium (0.02 eq), tri-tert-butylphosphine (0.05 eq) and sodium tert-butoxide (2.0 eq) were added under nitrogen protection. The mixture was stirred evenly, heated to 110°C, and reacted for 4 hours. After the reaction, the temperature was slightly lowered, and the mixture was filtered using diatomaceous earth to remove salts and the catalyst. The filtrate was cooled to room temperature and washed three times with water. The organic phase was retained, and the aqueous phase was extracted with ethyl acetate. The organic phases were combined and concentrated, and purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V dichloromethane:V petroleum ether = 1:5) to obtain intermediate 5 (yield: 72.1%).

[0116] Intermediate 5 (1.0 eq) was dissolved in toluene, and raw material F-177 (1.1 eq) (CAS No.: 2892121-20-7) was dissolved in toluene, and then the raw material F-177 solution was slowly added to the intermediate 5 solution. Then, the mixture was ventilated three times, and tris(dibenzylideneacetone)dipalladium (0.01eq), tri-tert-butylphosphine (0.05eq) and sodium tert-butoxide (2.0eq) were added under nitrogen protection, stirred evenly, heated to 110°C, and reacted for 10h; the reaction was detected by thin layer chromatography. After the reaction was completed, the temperature was slightly lowered, and the mixture was filtered using diatomaceous earth to remove salt and catalyst. The filtrate was cooled to room temperature and washed three times with water, retaining the organic phase, and then the aqueous phase was extracted with ethyl acetate; after combining the organic phases, they were dried over anhydrous magnesium sulfate, and the solvent was removed using a rotary evaporator; compound 177 was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V dichloromethane: V petroleum ether = 1:8) to obtain compound 177 (yield: 79.2%).

[0117] The obtained compound 177 was tested and analyzed, and the results were as follows:

[0118] HPLC purity: >99.7%.

[0119] Mass spectrometry test (mass spectrometry was performed using an ultra-high performance liquid chromatography-mass spectrometer and an ESI source, the same below): the test value was 640.01.

[0120] Elemental analysis:

[0121] Calculated values: C, 90.11; H, 5.20; N, 2.19; O, 2.50.

[0122] The test values are: C, 89.81; H, 5.37; N, 2.37; O, 2.71.

[0123] Example 3: Preparation of Compound 315

[0124] Intermediate 4 in Example 3 is a prior art (CAS No.: 2331184-24-6)

[0125]

[0126] Intermediate 4 (1.0 eq) was dissolved in toluene, and the raw material E-315 (1.2 eq) (CAS No.: 118951-68-1) was dissolved in toluene. The raw material E-315 solution was then slowly added to the intermediate 4 solution. The mixture was then ventilated three times, and tris(dibenzylideneacetone)dipalladium (0.02 eq), tri-tert-butylphosphine (0.05 eq) and sodium tert-butoxide (2.0 eq) were added under nitrogen protection. The mixture was stirred evenly, heated to 110°C, and reacted for 4 hours. After the reaction, the temperature was slightly lowered, and the mixture was filtered through diatomaceous earth to remove salts and catalyst. The filtrate was cooled to room temperature and washed three times with water. The organic phase was retained, and the aqueous phase was extracted with ethyl acetate. The organic phases were combined and concentrated, and purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V dichloromethane:V petroleum ether = 1:5) to obtain intermediate 5 (yield: 59.5%).

[0127] Intermediate 5 (1.0 eq) was dissolved in toluene, and raw material F-315 (1.1 eq) (CAS No.: 1338446-67-5) was dissolved in toluene, and then the raw material F-315 solution was slowly added to the intermediate 5 solution. The mixture was then ventilated three times, and tris(dibenzylideneacetone)dipalladium (0.01 eq), tri-tert-butylphosphine (0.05 eq) and sodium tert-butoxide (2.0 eq) were added under nitrogen protection, stirred evenly, heated to 110°C, and reacted for 10 h; the reaction was detected by thin layer chromatography. After the reaction was completed, the temperature was slightly lowered, and the product was filtered through diatomaceous earth to remove salt and catalyst. The filtrate was cooled to room temperature and washed three times with water, retaining the organic phase, and the aqueous phase was extracted with ethyl acetate; the organic phases were combined and dried over anhydrous magnesium sulfate, and the solvent was removed using a rotary evaporator; compound 315 was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V dichloromethane:V petroleum ether = 1:8) to obtain compound 315 (yield: 69.3%).

[0128] The obtained compound 315 was tested and analyzed, and the results were as follows:

[0129] HPLC purity: >99.8%.

[0130] Mass spectrometry test (mass spectrometry was performed using an ultra-high performance liquid chromatography-mass spectrometer and an ESI source, the same below): the test value was 828.24.

[0131] Elemental analysis:

[0132] Calculated values: C, 91.39; H, 4.99; N, 1.69; O, 1.93.

[0133] The test values are: C, 91.11; H, 5.16; N, 1.88; O, 2.11.

[0134] H NMR spectrum: Figure 2 shown.

[0135] Since the general structural formula is Chemical Formula I in the Summary of the Invention, the synthesis routes and principles of the other compounds are the same as those of the above-listed embodiments. Among them, Examples 4 to 60 of the present application can be prepared according to the above-mentioned preparation method to obtain the luminescent auxiliary materials shown in Table 1 below:

[0136] Table 1

[0137]

[0138]

[0139] The organic electroluminescent device is prepared using the luminescence auxiliary material provided in the above embodiment. When the organic layer is a luminescence auxiliary layer, the luminescence auxiliary layer includes the luminescence auxiliary material provided in the above embodiment.

[0140] Another object of the present application is to provide an organic electroluminescent device, comprising a first electrode, a second electrode, and at least one organic layer disposed between the first electrode and the second electrode.

[0141] The organic material layer of the organic light-emitting device disclosed in the present invention can be formed not only as a single-layer structure, but also as a multilayer structure having two or more organic material layers. For example, the organic light-emitting device can have a structure including a hole injection layer, a hole transport layer, a hole injection and transport layer, an electron blocking layer, a light-emitting layer, an electron transport layer, an electron injection layer, a hole blocking layer, an electron injection and transport layer, etc. as organic material layers. However, the structure of the organic light-emitting device is not limited thereto and can include a smaller number of organic material layers or a larger number of organic material layers.

[0142] As the anode material, a material with a large work function is generally preferred so that holes can be smoothly injected into the organic material layer. Specific examples of anode materials that can be used in the present invention include: metals such as vanadium, chromium, copper, zinc, gold, or alloys thereof; metal oxides such as zinc oxide, indium oxide, indium tin oxide (ITO), and indium zinc oxide (IZO); combinations of metals and oxides such as ZnO:Al or SnO2:Sb; conductive polymers such as poly(3-methylthiophene), poly[3,4-(ethylene-1,2-dioxy)thiophene] (PEDOT), polypyrrole, and polyaniline, but are not limited thereto.

[0143] The hole injection material is a material that advantageously receives holes from the anode at a low voltage, and the highest occupied molecular orbital (HOMO) of the hole injection material is preferably between the work function of the anode material and the HOMO of the surrounding organic material layer. Specific examples of the hole injection material include metal porphyrins, oligothiophenes, arylamine-based organic materials, hexanitrile hexaazatriphenylene-based organic materials, quinacridone-based organic materials, perylene-based organic materials, anthraquinone, and polyaniline-based and polythiophene-based conductive polymers, but are not limited thereto, and may also include compounds capable of p-doping.

[0144] The hole transport material is a material that can receive holes from the anode or hole injection layer and transport the holes to the light-emitting layer, and a material with high hole mobility is preferably selected. Specific examples thereof include, but are not limited to, organic materials based on arylamines, conductive polymers, and block copolymers having both conjugated and non-conjugated portions.

[0145] The light-emitting layer can emit red, green or blue light and can be formed of a phosphorescent material or a fluorescent material. The light-emitting material is a material that can emit light in the visible light region by receiving holes and electrons from the hole transport layer and the electron transport layer, respectively, and combining the holes with the electrons, and is preferably a material with a favorable quantum efficiency for fluorescence or phosphorescence. Specific examples thereof include: 8-hydroxyquinoline aluminum (Alq3); carbazole-based compounds; diphenylethylene compounds; BAlq; 10-hydroxybenzoquinoline-metal compounds; benzocarbazole-based, benzothiazole-based and benzimidazole-based compounds; poly(p-phenylene vinylene) (PPV)-based polymers; spirocyclic compounds; polyfluorene; rubrene, etc., but are not limited thereto.

[0146] The host material of the light-emitting layer includes fused aromatic ring derivatives, heterocyclic compounds, etc. Specifically, fused aromatic ring derivatives include anthracene derivatives, pyrene derivatives, naphthalene derivatives, pentacene derivatives, phenanthrene compounds, fluoranthene compounds, etc., and heterocyclic compounds include carbazole derivatives, dibenzofuran derivatives, ladder-type furan compounds, pyrimidine derivatives, etc., but are not limited thereto.

[0147] The electron transport layer can play a role in promoting electron transport. The electron transport material is a material that advantageously receives electrons from the cathode and transports the electrons to the light-emitting layer, and a material with high electron mobility is a suitable choice. Specific examples thereof include: Al complexes of 8-hydroxyquinoline; complexes containing Alq3; organic free radical compounds; hydroxyflavone-metal complexes, etc., but are not limited thereto. The thickness of the electron transport layer can be 1 nm to 50 nm. An electron transport layer with a thickness of 1 nm or more has the advantage of preventing the electron transport characteristics from decreasing, and a thickness of 50 nm or less has the advantage of preventing the increase in the driving voltage for enhancing electron migration caused by the electron transport layer being too thick.

[0148] The electron injection layer can promote electron injection, and the electron injection material is preferably a compound having the following functions:

[0149] The present invention relates to a novel nanostructured carbon nanotube having the ability to transport electrons, an electron injection effect from the cathode, an excellent electron injection effect into the light-emitting layer or light-emitting material, preventing excitons generated in the light-emitting layer from migrating to the hole injection layer, and excellent thin-film forming ability. Specific examples thereof include, but are not limited to, fluorenone, anthraquinone dimethane, diphenoquinone, thiopyran dioxide, azole, diazole, triazole, imidazole, perylenetetracarboxylic acid, fluorenylene methane, anthrone, and their derivatives, metal complexes, and nitrogen-containing five-membered ring derivatives.

[0150] Cathode materials are generally preferred, preferably those with a low work function to facilitate electron injection into the organic material layer. Specific examples of cathode materials include, but are not limited to, metals such as magnesium, calcium, sodium, potassium, titanium, indium, yttrium, lithium, gadolinium, aluminum, silver, tin, and lead, or alloys thereof; and multilayer structures such as LiF / Al or LiO2 / Al.

[0151] The devices described herein can be used in organic light-emitting devices, including but not limited to flat panel displays, computer monitors, medical monitors, televisions, billboards, lights for interior or exterior lighting and / or signaling, heads-up displays, fully or partially transparent displays, flexible displays, laser printers, telephones, mobile phones, tablets, photo albums, personal digital assistants (PDAs), wearable devices, laptop computers, digital cameras, video cameras, viewfinders, microdisplays, three-dimensional displays, virtual reality or augmented reality displays, vehicles, video walls comprising multiple displays tiled together, theater or stadium screens, light therapy devices, and signs.

[0152] Device Example 1: Preparation of red organic electroluminescent device

[0153] The structure of the prepared OLED device is: ITO anode / HIL / HTL / luminescence auxiliary layer / EML / HBL / ETL / EIL / cathode / light extraction layer

[0154] a. ITO anode: the coating thickness is The ITO (indium tin oxide)-Ag-ITO (indium tin oxide) glass substrate was cleaned twice in distilled water, ultrasonically washed for 30 minutes, and then repeatedly cleaned twice with distilled water, ultrasonically washed for 10 minutes. After washing, it was ultrasonically washed with methanol, acetone, and isopropanol in sequence (5 minutes each time), dried, and then transferred to a plasma cleaning machine for washing for 5 minutes. It was then sent to a vapor deposition machine, and the substrate was used as the anode, and other functional layers were evaporated on it in sequence.

[0155] b. HIL (hole injection layer): The hole injection layer materials HT-1 and P-dopant were vacuum evaporated at a deposition rate of 97:3, and the thickness was 10 nm.

[0156] c. HTL (hole transport layer): At a deposition rate of 1%, 130 nm of HT-1 was vacuum-deposited on the hole injection layer as a hole transport layer;

[0157] d. Luminous auxiliary layer: The compound 1 provided in the above embodiment was vacuum-deposited on the hole transport layer at a deposition rate of 10 nm as a light-emitting auxiliary layer;

[0158] e. EML (luminescent layer): Then on the above-mentioned luminescent auxiliary layer, The evaporation rate is 20 nm, and the main material (Host-1) and the dopant material (Dopant-1) with a thickness of 20 nm are vacuum evaporated as the light-emitting layer. The chemical formulas of Host-1 and Dopant-1 are shown below; the evaporation rate ratio of the double Host-1 and Dopant-1 is 98:2.

[0159] f. HBL (hole blocking layer): The hole blocking layer HB with a thickness of 5.0 nm was vacuum-deposited at a deposition rate of .

[0160] g. ETL (Electron Transport Layer): The evaporation rate was 35 nm, and ET-1 and Liq were vacuum evaporated to a thickness of 35 nm as the electron transport layer. The chemical formula of ET-1 is shown below; the evaporation rate ratio of ET-1 and Liq was 50:50.

[0161] h. EIL (electron injection layer): The evaporation rate is 1.0 nm, and a Yb film layer is evaporated to form an electron injection layer.

[0162] i. Cathode: The evaporation rate ratio of magnesium and silver is 13, and the evaporation rate ratio is 1:9 to obtain an OLED device.

[0163] j. Light extraction layer: At a deposition rate of , CPL-1 with a thickness of 70 nm was vacuum-deposited on the cathode as a light extraction layer.

[0164] k. The vapor-deposited substrate is then packaged. First, the cleaned cover is coated with UV glue using a glue coating device. Then the coated cover is moved to the pressing section, and the vapor-deposited substrate is placed on the upper end of the cover. Finally, the substrate and cover are bonded together using a bonding device, and the UV glue is cured by light.

[0165]

[0166] Referring to the method provided in the above device embodiment 1, the corresponding compounds in Table 2 were selected to replace compound 1, and the light-emitting auxiliary layer was evaporated to prepare the corresponding organic electroluminescent devices, which were respectively recorded as device embodiments 2 to 31.

[0167] Comparative Examples 1-9: These provide an organic electroluminescent device. The only difference between the preparation method of this organic electroluminescent device and that of Device Example 1 is that this organic electroluminescent device uses an existing comparative compound ai instead of the luminescent auxiliary material (Compound 1) in Device Example 1 for vapor deposition. The chemical structure of the comparative compound ai is as follows:

[0168]

[0169] The driving voltage, luminous efficiency and lifespan of the organic electroluminescent devices obtained from the device examples 1 to 31 and the device comparative examples 1 to 9 were characterized at a brightness of 6000 (nits). The test results are shown in Table 2 below:

[0170] Table 2

[0171]

[0172]

[0173] Device Example 32: Preparation of Green Organic Electroluminescent Device

[0174] The structure of the prepared OLED device is: ITO anode / HIL / HTL / luminescence auxiliary layer / EML / ETL / EIL / cathode / light extraction layer

[0175] a. ITO anode: the coating thickness is The ITO (indium tin oxide)-Ag-ITO (indium tin oxide) glass substrate was cleaned twice in distilled water, ultrasonically washed for 30 minutes, and then repeatedly cleaned twice with distilled water, ultrasonically washed for 10 minutes. After washing, it was ultrasonically washed with methanol, acetone, and isopropanol in sequence (5 minutes each time), dried, and then transferred to a plasma cleaning machine for washing for 5 minutes. It was then sent to a vapor deposition machine, and the substrate was used as the anode, and other functional layers were evaporated on it in sequence.

[0176] b. HIL (hole injection layer): The hole injection layer materials HT-1 and P-dopant were vacuum evaporated at a deposition rate of 97:3, and the thickness was 10 nm.

[0177] c. HTL (hole transport layer): At a deposition rate of 1%, 130 nm of HT-1 was vacuum-deposited on the hole injection layer as a hole transport layer;

[0178] d. Luminous auxiliary layer: The compound 1 provided in the above embodiment was vacuum-deposited on the hole transport layer at a deposition rate of 10 nm as a light-emitting auxiliary layer;

[0179] e. EML (luminescent layer): Then on the above-mentioned luminescent auxiliary layer, At a deposition rate of 100 nm, a 200nm thick layer of dual host materials (Host 1 and Host 2) and a dopant material (Dopant-1) was vacuum-deposited as the light-emitting layer, with a 50:50 ratio of Host 1 to Host 2. The chemical formulas of Host 1, Host 2, and Dopant are shown below; the deposition rate ratio of the dual host and dopant was 98:2.

[0180] f. HBL (hole blocking layer): The hole blocking layer HB with a thickness of 5.0 nm was vacuum-deposited at a deposition rate of .

[0181] g. ETL (Electron Transport Layer): The evaporation rate was 35 nm, and ET-1 and Liq were vacuum evaporated to a thickness of 35 nm as the electron transport layer. The chemical formula of ET-1 is shown below; the evaporation rate ratio of ET-1 and Liq was 50:50.

[0182] h. EIL (electron injection layer): The evaporation rate is 1.0 nm, and a Yb film layer is evaporated to form an electron injection layer.

[0183] i. Cathode: The evaporation rate ratio of magnesium and silver is 13m, and the evaporation rate ratio is 1:9 to obtain an OLED device.

[0184] j. Light extraction layer: At a deposition rate of , CPL-1 with a thickness of 70 nm was vacuum-deposited on the cathode as a light extraction layer.

[0185] k. The vapor-deposited substrate is then packaged. First, the cleaned cover is coated with UV glue using a glue coating device. The coated cover is then moved to the laminating section, where the vapor-deposited substrate is placed on top of the cover. Finally, the substrate and cover are laminated using a laminating device, and the UV glue is cured by light.

[0186]

[0187] Referring to the method provided in the above device embodiment 32, the corresponding compounds in Table 3 were selected to replace compound 1, and the luminescent auxiliary layer was evaporated to prepare the corresponding organic electroluminescent devices, which were respectively recorded as device embodiments 33-61.

[0188] Device Comparison Examples 10-18: This comparison example provides an organic electroluminescent device. The only difference between the preparation method of this organic electroluminescent device and that of device Example 32 is that this organic electroluminescent device uses the existing comparison compound ai to replace the luminescent auxiliary material (compound 1) in the above-mentioned device Example 32 for vapor deposition.

[0189] The driving voltage, luminous efficiency and lifespan of the organic electroluminescent devices obtained from the device examples 32 to 61 and the device comparative examples 10 to 18 were characterized at a brightness of 15,000 (nits). The test results are shown in Table 3 below:

[0190] Table 3

[0191]

[0192]

[0193] As can be seen from Tables 2 and 3, for both green and red devices, device performance can be modified by changing the connection position, substituents, and the position of the substituents. Compared to organic electroluminescent devices prepared using the luminescent auxiliary materials provided herein, organic electroluminescent devices prepared using the comparative example compounds exhibit improved device efficiency and lifespan.

[0194] Comparative compounds a and b, and compounds 47 and 48, are parallel comparative examples. The difference between them is that the triarylamine in this application is connected to dibenzofuran on one side of its nitrogen atom, while comparative compounds a and b are connected to dibenzothiophene. Due to the different electronegativity of O and S, the HOMO and LUMO values of the compounds differ. Furthermore, dibenzofuran is more electrochemically stable, which is more conducive to improving the compound's migration rate. When used in devices, it can reduce the hole transport barrier and improve luminescence efficiency.

[0195] Comparative Compound D and Compound 1 are parallel comparative examples, differing in that Comparative Compound D is linked to 9,9-dimethylfluorene, while the present invention uses 9-alkyl-9-phenylfluorene. In the present invention, Compound 1, compared to Comparative Compound D, increases the molecular weight of the compound without increasing the conjugated system of the triarylamine, making the compound more stable and avoiding the possibility of cracking due to elevated evaporation temperatures during a long evaporation process, thereby improving device life.

[0196] Comparative compound f and compound 106 are parallel comparative examples, the difference between them is that: the dibenzofuran of comparative compound f has no other substituents connected to it, while the dibenzofuran in this application has a diphenyl group connected as a substituent, which extends the conjugated system of the compound, avoids the localization of carrier migration, and thus reduces the driving voltage.

[0197] Comparative compound g and compound 49 are parallel comparative examples, the difference between them is that one side of the triarylamine N atom in comparative compound g is connected to 9,9-diphenylfluorene, while the side connected to the triarylamine N atom in this application contains dibenzofuran, which is an electron-withdrawing group, which improves the migration rate of the compound. When it is used in a device, it can reduce the hole transport energy barrier and improve the luminescence efficiency.

[0198] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present application. Various modifications to these embodiments will be readily apparent to one 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 present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A luminescence auxiliary material, characterized in that: The general structural formula of the luminescence auxiliary material is shown in Chemical Formula I: The specific structure is as follows: 。 2. A method for preparing the luminescence auxiliary material according to claim 1, characterized in that: The specific steps include: 1) Raw materials A and B were dissolved in a mixed solution of toluene, ethanol, and water, respectively. The raw material B solution was then slowly added to the raw material A solution. Potassium carbonate and tetrakis(triphenylphosphine)palladium were added under nitrogen protection and stirred evenly. The temperature was raised to 80°C-120°C and refluxed for 4-12 hours to obtain intermediate 1; 2) Dissolve the intermediate 1 in tetrahydrofuran solution, slowly add n-butyl lithium and react for 2 hours, then slowly add benzaldehyde dropwise and stir evenly, increase the temperature and continue the reaction for 4-12 hours to obtain intermediate 2; 3) The intermediate 2 was dissolved in DCM, and boron trifluoride ether was added to react for 0.2-2 h to obtain intermediate 3; 4) The intermediate 3 was dissolved in THF, t-BuOK was slowly added and stirred for 1 hour, and then CH3I was slowly added dropwise. The temperature was raised to 70-90°C and the reaction was carried out for 8-12 hours to obtain intermediate 4; 5) Dissolve the intermediate 4 in toluene, dissolve the raw material E in toluene, then slowly add the raw material E solution to the intermediate 4 solution, add tris(dibenzylideneacetone)dipalladium, tri-tert-butylphosphine and sodium tert-butoxide under nitrogen protection, stir evenly, raise the temperature to 100°C-120°C and react for 1-4 hours to obtain intermediate 5; 6) The intermediate 5 is dissolved in toluene, and the raw material F is dissolved in toluene. The raw material F solution is then slowly added to the intermediate 5 solution. Tris(dibenzylideneacetone)dipalladium, tri-tert-butylphosphine and sodium tert-butoxide are added under nitrogen protection, stirred evenly, and heated to 110° C.-120° C. for 8-12 hours to obtain a luminescent auxiliary material as shown in Chemical Formula I; The structural formulas of the raw material A, raw material B, raw material E, and raw material F are as follows: Hal is independently selected from chlorine, bromine or iodine.

3. An organic electroluminescent device, characterized in that: The organic electroluminescent device comprises the luminescence auxiliary material according to claim 1 .

4. The organic electroluminescent device according to claim 3, characterized in that: The organic electroluminescent device comprises a luminescence auxiliary layer; the luminescence auxiliary layer comprises the luminescence auxiliary material.

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