Luminescent auxiliary material, preparation method thereof and organic electroluminescent device comprising luminescent auxiliary material

Abstract

The invention belongs to the field of organic photoelectric materials, and provides a light-emitting auxiliary material, a preparation method thereof and an organic electroluminescent device containing the light-emitting auxiliary material. On one hand, on the basis that a 9-alkyl-9 phenyl-fluorene group is introduced into a triarylamine molecule serving as a hole transport functional group, the molecular weight of the compound is limited to a reasonable atom number, then the molecular weight of the whole molecule is balanced, the evaporation temperature is regulated and controlled, and the situation that the service life of a device is affected due to the fact that the evaporation temperature is too high is avoided; on the other hand, the migration rate of the compound is improved by introducing dibenzofuran, and after the compound is applied to a device, hole transport energy barrier can be reduced, and luminous efficiency is improved; in addition, by introducing different substituents of Ar or changing different connection positions, a conjugated system of the compound is prolonged, so that adjustment of different photoelectric properties and thermal properties is realized.

Description

[0001] This application is a divisional application of patent application number 202310881708.1, the original application being filed on July 18, 2023, entitled "A Light-Emitting Auxiliary Material and Its Preparation Method and an Organic Electroluminescent Device Containing the Same," and is applied to the divisional application. Technical Field

[0002] This application belongs to the field of organic optoelectronic materials technology, and particularly relates to a light-emitting auxiliary material, its preparation method, and an organic electroluminescent device containing the same. Background Technology

[0003] Organic light emission refers to the phenomenon of converting electrical energy into light energy using organic materials. Organic light-emitting devices that utilize organic light emission have wide viewing angles, excellent contrast, fast response times, and superior characteristics in terms of brightness, driving voltage, and response speed. Therefore, they are currently the subject of extensive research.

[0004] This organic electroluminescent device utilizes charges injected from two electrodes to recombine in the emissive layer to generate light. In this case, efficiently transferring the charges of holes and electrons to the emissive layer is crucial, and the device requires excellent carrier balance. Furthermore, the luminescence efficiency is improved by enhancing the hole injection and electron blocking properties that impede electrons injected from the cathode to increase the recombination probability, and by confining the excitons generated within the emissive layer. Therefore, the role of the luminescent auxiliary material is extremely important.

[0005] Research on organic electroluminescent materials has been extensive in academia and industry. However, stable and efficient organic layer materials for organic electrical components have not yet been fully developed, and the industrialization of this technology still faces many key challenges, such as high driving voltage, low luminous efficiency, and short lifespan in the fabricated devices. Therefore, developing new materials remains a pressing issue for those skilled in the art. Summary of the Invention

[0006] The purpose of this application is to provide a light-emitting auxiliary material so that when applied to an organic electroluminescent device, the resulting device has the technical effects of low driving voltage, high luminous efficiency, and / or long service life.

[0007] The primary technical objective of this invention is to provide a luminescent auxiliary material, the general structural formula of which is shown in chemical formula I:

[0008]

[0009] In chemical formula I:

[0010] R1, R2, and R3 can 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.

[0011] Ar is independently selected from the following groups:

[0012]

[0013] 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.

[0014] R5 is selected from substituted or unsubstituted C6-C12 aryl or substituted or unsubstituted C6-C12 heteroaryl, 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 selected from integers of 0 or 1, and s and t cannot be 0 at the same time.

[0015] Furthermore, R1, R2, and R3 can be the same or different, and can independently represent phenyl, biphenyl, and naphthyl, respectively;

[0016] R4 is selected from hydrogen, methyl, phenyl, naphthyl, and biphenyl; R5 is selected from phenyl, naphthyl, and biphenyl.

[0017] The further preferred structural formula of the above chemical formula I is:

[0018]

[0019] In the above chemical formulas -I-1 to -I-2, R1, R2, R3, m, and Ar are defined as above, and s and t are integers of 1.

[0020] In this description, "substitution" means substitution by one, two or more substituents selected from the following: hydrogen, deuterium, halogen, cyano, trifluoromethyl, methyl, ethyl, propyl, n-propyl, isopropyl, butyl, n-butyl, isobutyl, tert-butyl, sec-butyl, 1-methylbutyl, 1-ethylbutyl, pentyl, n-pentyl, isopentyl, neopentyl, tert-pentyl, hexyl, n-hexyl, 1-methylpentyl, 2-methylpentyl, 4-methyl-2-pentyl, 3,3-dimethylbutyl, 2-ethylbutyl, 1-methylhexyl, phenyl, naphthyl, anthracene, phenanthrene, thiophene, furanyl, pyrrole, benzothiophene, benzofuranyl, pyridyl, indolyl, cyclopentyl, cyclohexyl, adamantane.

[0021] In the above technical solution, it is further preferred that the luminescent auxiliary material is any one of the following structures, but not limited to:

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[0074] The second technical objective of this application is to provide a method for preparing the aforementioned luminescent auxiliary material. Synthetic route:

[0075]

[0076] 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.

[0077] It is worth noting that, compared to the undisclosed and complex starting materials, 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:

[0078] Step 1: Preparation of Intermediate 1

[0079] Raw material A (1.0 eq) was dissolved in a mixed solution of toluene, ethanol, and water, and raw material B (1.2 eq) was dissolved in the same mixed solution. The solution of raw material B was then slowly added to the solution of raw material A. After three purgings, potassium carbonate (3.0 eq) and tetrakis(triphenylphosphine)palladium (0.01 eq) were added under nitrogen protection. The mixture was stirred until homogeneous, heated to 80℃-120℃, and refluxed for 4-12 hours. The reaction was detected using thin-layer chromatography. After the reaction was complete, the temperature was slightly lowered, and the mixture was filtered through diatomaceous earth to remove salts and catalysts. The filtrate was cooled to room temperature, washed three times with water, and the organic phase was retained. The aqueous phase was then extracted with ethyl acetate. The combined organic phases were concentrated, and intermediate 1 was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (Vdichloromethane:Vpetroleum ether = 1:3).

[0080] Note: In this reaction step, starting material A contains three 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:

[0081] 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.

[0082] Organic Chemistry and Optoelectronic Materials Experiment Tutorial, Chen Runfeng, Publisher: Southeast University Press, Publication Date: 2019-11-00, ISBN: 9787564184230, Page 174.

[0083] Step 2, Preparation of Intermediate 2

[0084] The mixture was cooled to -78℃, and intermediate 1 (1.2 eq) was dissolved in tetrahydrofuran solution. After 3 aeration cycles and stirring for 10 minutes, n-butyllithium (1.2 eq) was slowly added to the solution of intermediate 1. After reacting for 2 hours, starting material C was slowly added dropwise to the reaction flask, stirred until homogeneous, and the refrigeration was stopped. The mixture was then heated to room temperature and the reaction continued for 4-12 hours. 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 ethyl acetate. The organic phases were combined and concentrated. Intermediate 2 was obtained by column chromatography using a mixed solution of dichloromethane and petroleum ether (V dichloromethane:V petroleum ether = 1:2).

[0085] Step 3, Preparation of Intermediate 3

[0086] Intermediate 2 (1.0 eq) was dissolved in DCM and stirred at room temperature until dissolved. Then, boron trifluoride ether (5.0 eq) was added to the intermediate 2 solution, stirred until homogeneous, and reacted for 0.2-2 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 ethyl acetate. The organic phases were combined and dried with anhydrous magnesium sulfate, and the solvent was removed using a rotary evaporator. The solid organic matter was completely dissolved with a small amount of dichloromethane and then slowly added dropwise to a petroleum ether solution. The mixture was stirred until homogeneous, and a precipitate was formed. The precipitate was filtered to obtain a solid, which was washed successively with anhydrous ethanol and petroleum ether, and then dried to obtain intermediate 3.

[0087] Step 4, Preparation of Intermediate 4

[0088] Intermediate 3 (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 one hour. Then, CH3I (5.0 eq) was slowly added dropwise, and the temperature was raised to 70-90℃. The reaction was allowed to proceed for 8-12 hours. 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 salts. The filtrate was cooled to room temperature and washed three times with water, retaining the organic phase. The aqueous phase was then extracted with ethyl acetate. The organic phases were combined and dried with anhydrous magnesium sulfate, and the solvent was removed using a rotary evaporator. The solid organic matter was completely dissolved with a small amount of dichloromethane and then slowly added dropwise to a petroleum ether solution. The mixture was stirred until a precipitate formed. The precipitate was filtered to obtain a solid, which was then washed successively with anhydrous ethanol and petroleum ether and dried to obtain intermediate 4.

[0089] Step 5, Preparation of Intermediate 5

[0090] Intermediate 4 (1.0 eq) was dissolved in toluene, and starting material E (1.2 eq) was dissolved in toluene. The solution of starting material E was then slowly added to the solution of intermediate 4. After three purgings, tris(dibenzylacetone)dipalladium (0.01-0.02 eq), tri-tert-butylphosphine (0.05 eq), and sodium tert-butoxide (2.0 eq) were added under nitrogen protection. The mixture was stirred thoroughly and heated to 100-120°C for 1-4 hours. The reaction was detected by thin-layer chromatography. After the reaction was complete, the temperature was slightly lowered, and the mixture was filtered through diatomaceous earth to remove salts and catalysts. The filtrate was cooled to room temperature and washed three times with water, retaining the organic phase. The aqueous phase was then extracted with ethyl acetate. The combined organic phases were concentrated, and intermediate 5 was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V:5 = 1:5).

[0091] Step 6, Preparation of Chemical Formula I

[0092] Intermediate 5 (1.0 eq) was dissolved in toluene, and starting material F (1.1 eq) was dissolved in toluene. The solution of starting material F was then slowly added to the solution of intermediate 5. After three purgings, tris(dibenzylacetone)dipalladium (0.01-0.02 eq), tri-tert-butylphosphine (0.05 eq), and sodium tert-butoxide (2.0 eq) were added under nitrogen protection. The mixture was stirred thoroughly and heated to 110-120°C for 8-12 hours. The reaction was detected by thin-layer chromatography. After the reaction was complete, the temperature was slightly lowered, and the mixture was filtered through diatomaceous earth to remove salts and catalysts. The filtrate was cooled to room temperature and washed three times with water, retaining the organic phase. The aqueous phase was then extracted with ethyl acetate. The combined organic phases were dried over anhydrous magnesium sulfate, and the solvent was removed using a rotary evaporator. The solution of dichloromethane and petroleum ether (V:V:Petroleum ether = 1:8) was purified by column chromatography to obtain chemical formula I.

[0093] The third technical objective of this application is to provide an organic electroluminescent device, which includes the aforementioned light-emitting auxiliary material.

[0094] Furthermore, the organic electroluminescent device includes a light-emitting auxiliary layer; the light-emitting auxiliary layer includes the aforementioned light-emitting auxiliary material.

[0095] The fourth technical objective of this application is to provide an organic light-emitting device, which includes the aforementioned organic electroluminescent device.

[0096] The luminescent auxiliary material provided in this application, on the one hand, limits the molecular weight of the compound to a reasonable number of atoms by introducing a 9-alkyl-9-phenyl-fluorene group into the triarylamine molecule, which serves as a hole transport functional group, thereby balancing the overall molecular weight of the molecule and controlling the evaporation temperature to prevent it from being too high and affecting the device lifespan; on the other hand, it improves the migration rate of the compound by introducing dibenzofuran, which can reduce the hole transport barrier and improve the luminescent efficiency after being used in the device; and the present invention extends the conjugated system of the compound by introducing different substituents of Ar or changing different connection positions, thereby achieving different adjustment of photoelectric and thermal properties. Attached Figure Description

[0097] Figure 1 This is the 1H NMR spectrum of compound 1 provided in Example 1 of this application;

[0098] Figure 2 This is the 1H NMR spectrum of compound 315 provided in Example 3 of this application. Detailed Implementation

[0099] This application provides a light-emitting auxiliary material, a method for preparing the same, and an organic electroluminescent device containing the same.

[0100] The technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the luminescent auxiliary material of this application. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0101] Example 1: Preparation of Compound 1

[0102] Intermediate 4 in Example 1 is prior art (CAS No.: 2842863-92-5).

[0103]

[0104] Intermediate 4 (1.0 eq) was dissolved in toluene, and starting material E-1 (1.2 eq) (CAS No.: 1795019-74-7) was dissolved in toluene. The solution of starting material E-1 was then slowly added to the solution of intermediate 4. After three purgings, tris(dibenzylacetone)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 until homogeneous, heated to 110°C, and reacted for 4 hours. After the reaction was complete, the temperature was slightly lowered, and the mixture was filtered through diatomaceous earth to remove salts and catalysts. The filtrate was cooled to room temperature, washed three times with water, and the organic phase was retained. The aqueous phase was then extracted with ethyl acetate. The combined organic phases were concentrated, and intermediate 5 (yield: 80.6%) was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V:5).

[0105] 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. Then, the raw material F-1 solution was slowly added to the intermediate 5 solution. The mixture was then ventilated three times, and under nitrogen protection, tris(dibenzylacetone)dipalladium (0.01 eq), tri-tert-butylphosphine (0.05 eq), and sodium tert-butoxide (2.0 eq) were added. The mixture was stirred until homogeneous, 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 mixture was filtered through diatomaceous earth to remove salts and catalysts. The filtrate was cooled to room temperature and washed three times with water, retaining the organic phase. The aqueous phase was then extracted with ethyl acetate. The organic phases were combined and dried with 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:V:Petroleum ether = 1:8) to obtain compound 1 (yield: 85.2%).

[0106] The obtained compound 1 was analyzed, and the results are as follows:

[0107] HPLC purity: >99.8%.

[0108] Mass spectrometry test (mass spectrometry was performed using an ultra-high performance liquid chromatography-mass spectrometry system with an ESI source, the same below): the test value was 751.4.

[0109] Elemental analysis:

[0110] The calculated values ​​are: C, 90.66; H, 5.30; N, 1.89; O, 2.16.

[0111] The test values ​​were: C, 90.38; H, 5.48; N, 2.08; O, 2.35.

[0112] Nuclear magnetic resonance hydrogen spectrum: as shown Figure 1 As shown.

[0113] Example 2: Preparation of compound 177

[0114] Intermediate 4 in Example 2 is prior art (CAS No.: 2331184-24-6).

[0115]

[0116] Intermediate 4 (1.0 eq) was dissolved in toluene, and starting material E-177 (1.2 eq) (CAS No.: 134-32-7) was dissolved in toluene. The E-177 solution was then slowly added to the intermediate 4 solution. After three purgings, tris(dibenzylacetone)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 until homogeneous, heated to 110°C, and reacted for 4 hours. After the reaction was complete, the temperature was slightly lowered, and the mixture was filtered through diatomaceous earth to remove salts and catalysts. The filtrate was cooled to room temperature, washed three times with water, and the organic phase was retained. The aqueous phase was then extracted with ethyl acetate. The combined organic phases were concentrated, and intermediate 5 (yield: 72.1%) was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V:5).

[0117] 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. Then, the raw material F-177 solution was slowly added to the intermediate 5 solution. The mixture was then ventilated three times, and under nitrogen protection, tris(dibenzylacetone)dipalladium (0.01 eq), tri-tert-butylphosphine (0.05 eq), and sodium tert-butoxide (2.0 eq) were added. The mixture was stirred until homogeneous, 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 mixture was filtered through diatomaceous earth to remove salts and catalysts. The filtrate was cooled to room temperature and washed three times with water, retaining the organic phase. The aqueous phase was then extracted with ethyl acetate. The organic phases were combined and dried with 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:V:Petroleum ether = 1:8) (yield: 79.2%).

[0118] The obtained compound 177 was analyzed, and the results are as follows:

[0119] HPLC purity: >99.7%.

[0120] Mass spectrometry test (mass spectrometry was performed using an ultra-high performance liquid chromatography-mass spectrometry system with an ESI source, the same below): the test value was 640.01.

[0121] Elemental analysis:

[0122] The calculated values ​​are: C, 90.11; H, 5.20; N, 2.19; O, 2.50.

[0123] The test values ​​were: C, 89.81; H, 5.37; N, 2.37; O, 2.71.

[0124] Example 3: Preparation of compound 315

[0125] Intermediate 4 in Example 3 is prior art (CAS No.: 2331184-24-6).

[0126]

[0127] Intermediate 4 (1.0 eq) was dissolved in toluene, and starting material E-315 (1.2 eq) (CAS No.: 118951-68-1) was dissolved in toluene. The E-315 solution was then slowly added to the intermediate 4 solution. After three purgings, tris(dibenzylacetone)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 until homogeneous, heated to 110°C, and reacted for 4 hours. After the reaction was complete, the temperature was slightly lowered, and the mixture was filtered through diatomaceous earth to remove salts and catalysts. The filtrate was cooled to room temperature, washed three times with water, and the organic phase was retained. The aqueous phase was then extracted with ethyl acetate. The combined organic phases were concentrated, and intermediate 5 (yield: 59.5%) was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V:5)

[0128] 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. Then, the raw material F-315 solution was slowly added to the intermediate 5 solution. The mixture was then ventilated three times, and under nitrogen protection, tris(dibenzylacetone)dipalladium (0.01 eq), tri-tert-butylphosphine (0.05 eq), and sodium tert-butoxide (2.0 eq) were added. The mixture was stirred until homogeneous, 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 mixture was filtered through diatomaceous earth to remove salts and catalysts. The filtrate was cooled to room temperature and washed three times with water, retaining the organic phase. The aqueous phase was then extracted with ethyl acetate. The organic phases were combined and dried with anhydrous magnesium sulfate, and the solvent was removed using a rotary evaporator. Compound 315 (yield: 69.3%) was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V:Petroleum ether = 1:8).

[0129] The obtained compound 315 was analyzed, and the results are as follows:

[0130] HPLC purity: >99.8%.

[0131] Mass spectrometry test (mass spectrometry was performed using an ultra-high performance liquid chromatography-mass spectrometry system with an ESI source, the same below): the test value was 828.24.

[0132] Elemental analysis:

[0133] The calculated values ​​are: C, 91.39; H, 4.99; N, 1.69; O, 1.93.

[0134] The test values ​​are: C, 91.11; H, 5.16; N, 1.88; O, 2.11.

[0135] Nuclear magnetic resonance hydrogen spectrum: as shown Figure 2 As shown.

[0136] Since the general structural formula is Chemical Formula I as described in the invention, the synthetic routes and principles of other compounds are the same as those listed in the examples above. Specifically, Examples 4-60 of this application, prepared according to the above method, yield the luminescent auxiliary materials shown in Table 1 below:

[0137] Table 1

[0138]

[0139]

[0140] When the organic layer is used as the light-emitting auxiliary layer in the organic electroluminescent device prepared by the above embodiments, the light-emitting auxiliary layer includes the light-emitting auxiliary material provided in the above embodiments.

[0141] Another objective of this application is to provide an organic electroluminescent device, including a first electrode, a second electrode, and at least one organic layer disposed between the first electrode and the second electrode.

[0142] The organic material layer of the organic light-emitting device disclosed in this invention can be formed not only as a single-layer structure, but also as a multilayer structure with one or more organic material layers. For example, the organic light-emitting device may have a structure comprising 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, and an electron injection and transport layer as organic material layers. However, the structure of the organic light-emitting device is not limited to this, and may include fewer or more organic material layers.

[0143] As an anode material, a material with a high work function is generally preferred to facilitate the injection of holes into the organic material layer. Specific examples of anode materials that can be used in this 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-dioxo)thiophene] (PEDOT), polypyrrole, and polyaniline, but not limited thereto.

[0144] Hole-injecting materials are advantageously designed to receive holes from the anode at low voltages, and the highest occupied molecular orbital (HOMO) of the hole-injecting material is preferably located between the work function of the anode material and the HOMO of the surrounding organic material layer. Specific examples of hole-injecting materials include, but are not limited to, metalloporphyrins, oligothiophenes, arylamine-based organic materials, hexanitrile-hexaazabenzophenanthrene-based organic materials, quinacridone-based organic materials, perylene-based organic materials, anthraquinones, and conductive polymers based on polyaniline and polythiophene, and may also include compounds capable of p-doping.

[0145] Hole transport materials are materials capable of receiving holes from the anode or hole injection layer and transporting them to the light-emitting layer, with materials having high hole mobility being a suitable choice. Specific examples include, but are not limited to, arylamine-based organic materials, conductive polymers, and block copolymers having both conjugated and non-conjugated portions.

[0146] The luminescent layer can emit red, green, or blue light and can be formed from phosphorescent or fluorescent materials. The luminescent material is a material capable of emitting light in the visible light region by receiving holes and electrons from the hole transport layer and electron transport layer, respectively, and by combining the holes with the electrons, and is preferably a material with favorable quantum efficiency for fluorescence or phosphorescence. Specific examples include: 8-hydroxyquinoline aluminum ligand (Alq3); carbazole-based compounds; dipolystyrene-based compounds; BAlq; 10-hydroxybenzoquinoline-metal compounds; compounds based on benzocarbazole, benzothiazole, and benzimidazole; polymers based on poly(p-phenylenevinylene) (PPV); spirocyclic compounds; polyfluorene; fluorene, etc., but not limited to these.

[0147] The main materials of the luminescent layer include fused aromatic ring derivatives and heterocyclic compounds. Specifically, fused aromatic ring derivatives include anthracene derivatives, pyrene derivatives, naphthalene derivatives, pentanebenzene 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 to these.

[0148] The electron transport layer plays a crucial role in facilitating electron transport. Electron transport materials are those that advantageously receive electrons from the cathode and transport them to the emitting layer; materials with high electron mobility are suitable choices. Specific examples include, but are not limited to, Al complexes of 8-hydroxyquinoline; complexes containing Alq3; organic radical compounds; hydroxyflavonoid-metal complexes, etc. The thickness of the electron transport layer can range from 1 nm to 50 nm. Electron transport layers with a thickness of 1 nm or greater have the advantage of preventing a decrease in electron transport properties, while thicknesses of 50 nm or less have the advantage of preventing an increase in the driving voltage required to enhance electron migration due to excessive electron transport layer thickness.

[0149] The electron injection layer can promote electron injection, and the preferred electron injection material is a compound with the following functions:

[0150] It possesses the ability to transport electrons, exhibits an electron injection effect from the cathode, and demonstrates excellent electron injection effect on the luminescent layer or luminescent material, preventing excitons generated in the luminescent layer from migrating to the hole injection layer. Furthermore, it exhibits excellent thin film formation capabilities. Specific examples include fluorenones, anthraquinone dimethane, biphenylquinone, thiamethane dioxide, azoles, diazoles, triazoles, imidazoles, perylenetetracarboxylic acid, fluorenemethane, anthrones, and their derivatives, metal complexes, nitrogen-containing 5-membered ring derivatives, etc., but are not limited to these.

[0151] As cathode materials, materials with low work functions are generally preferred to facilitate electron injection into the organic material layer. Specific examples of cathode materials include: metals, such as magnesium, calcium, sodium, potassium, titanium, indium, yttrium, lithium, gadolinium, aluminum, silver, tin, and lead, or alloys thereof; multilayer materials, such as LiF / Al or LiO2 / Al, etc., but are not limited to these.

[0152] The devices described in this application can be used in organic light-emitting devices, 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.

[0153] Device Example 1: Fabrication of a Red Organic Light Emitting Device

[0154] The structure of the fabricated OLED device is as follows: ITO anode / HIL / HTL / light-emitting auxiliary layer / EML / HBL / ETL / EIL / cathode / light extraction layer

[0155] a. ITO anode: The coating thickness is... The ITO (indium tin oxide)-Ag-ITO (indium tin oxide) glass substrate was cleaned twice with distilled water and ultrasonically washed for 30 minutes. Then it was cleaned twice more with distilled water and ultrasonically washed for 10 minutes. After the washing was completed, 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 the substrate as the anode, other functional layers were sequentially vapor deposited on it.

[0156] b. HIL (Hole Injection Layer): The evaporation rate of the vacuum evaporation hole injection layer material HT-1 and P-dopant is as follows; the evaporation rate ratio of HT-1 and P-dopant is 97:3, and the thickness is 10nm.

[0157] c. HTL (Hole Transport Layer): At the evaporation rate, HT-1 of 130 nm was vacuum-deposited on the hole injection layer as a hole transport layer.

[0158] d. Light-emitting auxiliary layer: The above-described embodiment provides compound 1 as a light-emitting auxiliary layer is vacuum-deposited at a deposition rate of 10 nm on the hole transport layer.

[0159] e. EML (Emitting Layer): Then, on the above-mentioned emitting auxiliary layer, with... The evaporation rate is such that a host material (Host-1) and a dopant material (Dopant-1) with a vacuum evaporation thickness of 20 nm are used as the light-emitting layer. The chemical formulas of Host-1 and Dopant-1 are shown below; the evaporation rate ratio of the two Host-1 and Dopant-1 is 98:2.

[0160] f. HBL (Hole Blocking Layer): with The evaporation rate was high, and a hole blocking layer HB with a thickness of 5.0 nm was vacuum-deposited.

[0161] g. ETL (Electron Transport Layer): The evaporation rate was determined by vacuum evaporation of ET-1 and Liq with a thickness of 35 nm as electron transport layers. The chemical formula of ET-1 is shown below. The evaporation rate ratio of ET-1 to Liq is 50:50.

[0162] h, EIL (Electron Injection Layer): with The evaporation rate was such that a Yb film layer of 1.0 nm was deposited to form an electron injection layer.

[0163] i. Cathode: with The evaporation rate ratio of magnesium and silver is 1:9, resulting in an OLED device.

[0164] j. Optical extraction layer: with The evaporation rate was such that a 70 nm thick CPL-1 layer was vacuum-deposited on the cathode as a light extraction layer.

[0165] k. Subsequently, the substrate after vapor deposition is packaged. First, the cleaned cover plate is coated with UV adhesive using an adhesive coating equipment. Then, the coated cover plate is moved to the lamination section, and the vapor-deposited substrate is placed on the top of the cover plate. Finally, the substrate and cover plate are laminated under the action of the lamination equipment, and the UV adhesive is cured by light at the same time.

[0166]

[0167] Referring to the method provided in Device Example 1 above, the corresponding compounds in Table 2 were selected to replace compound 1, and the light-emitting auxiliary layer was deposited to prepare the corresponding organic electroluminescent devices, which are respectively referred to as Device Examples 2 to 31.

[0168] Comparative Examples 1-9: Comparative examples provide an organic electroluminescent device. The only difference between this organic electroluminescent device and Device Example 1 is that the latter uses the existing comparative compound ai instead of the luminescent auxiliary material (compound 1) in Device Example 1 for vapor deposition. The chemical structural formula of the comparative compound ai is as follows:

[0169]

[0170] The driving voltage, luminous efficiency, and lifetime of the organic electroluminescent devices obtained in Examples 1-31 and Comparative Examples 1-9 were characterized at a brightness of 6000 nits. The test results are shown in Table 2 below.

[0171] Table 2

[0172]

[0173]

[0174] Device Example 32: Fabrication of Green Organic Light Emitting Device

[0175] The structure of the fabricated OLED device is: ITO anode / HIL / HTL / light-emitting auxiliary layer / EML / ETL / EIL / cathode / light extraction layer

[0176] a. ITO anode: The coating thickness is... The ITO (indium tin oxide)-Ag-ITO (indium tin oxide) glass substrate was cleaned twice with distilled water, ultrasonically washed for 30 minutes, then repeatedly cleaned twice with distilled water, ultrasonically washed for 10 minutes. After washing, it was ultrasonically washed sequentially with methanol, acetone, and isopropanol (5 minutes each time), dried, and then transferred to a plasma cleaner for 5 minutes. Finally, it was sent to an evaporation machine, where other functional layers were sequentially deposited on the substrate as the anode.

[0177] b. HIL (Hole Injection Layer): The evaporation rate of the vacuum evaporation hole injection layer material HT-1 and P-dopant is as follows; the evaporation rate ratio of HT-1 and P-dopant is 97:3, and the thickness is 10nm.

[0178] c. HTL (Hole Transport Layer): At the evaporation rate, HT-1 of 130 nm was vacuum-deposited on the hole injection layer as a hole transport layer.

[0179] d. Light-emitting auxiliary layer: The above-described embodiment provides compound 1 as a light-emitting auxiliary layer is vacuum-deposited at a deposition rate of 10 nm on the hole transport layer.

[0180] e. EML (Emitting Layer): Then, on the above-mentioned emitting auxiliary layer, with... The evaporation rate was determined by vacuum evaporation of a dual host material (Host1 and Host2) and a dopant material (Dopant-1) with a thickness of 200 nm as the luminescent layer, with a Host1 to Host2 ratio of 50:50. The chemical formulas of Host1, Host2, and Dopant are shown below; the evaporation rate ratio of the dual host and Dopant is 98:2.

[0181] f. HBL (Hole Blocking Layer): with The evaporation rate was high, and a hole blocking layer HB with a thickness of 5.0 nm was vacuum-deposited.

[0182] g. ETL (Electron Transport Layer): The evaporation rate was determined by vacuum evaporation of ET-1 and Liq with a thickness of 35 nm as electron transport layers. The chemical formula of ET-1 is shown below. The evaporation rate ratio of ET-1 to Liq is 50:50.

[0183] h, EIL (Electron Injection Layer): with The evaporation rate was such that a Yb film layer of 1.0 nm was deposited to form an electron injection layer.

[0184] i. Cathode: with The evaporation rate ratio of magnesium and silver was 1:9, resulting in an OLED device.

[0185] j. Optical extraction layer: with The evaporation rate was such that a 70 nm thick CPL-1 layer was vacuum-deposited on the cathode as a light extraction layer.

[0186] k. Subsequently, the vapor-deposited substrate is encapsulated. First, the cleaned cover plate is coated with UV adhesive using an adhesive coating equipment. Then, the coated cover plate is moved to the lamination section, and the vapor-deposited substrate is placed on the top of the cover plate. Finally, the substrate and cover plate are laminated under the action of the lamination equipment, while the UV adhesive is cured by light.

[0187]

[0188] Referring to the method provided in Device Example 32 above, the corresponding compounds in Table 3 were selected to replace compound 1, and the light-emitting auxiliary layer was deposited by vapor deposition to prepare the corresponding organic electroluminescent devices, which are respectively referred to as Device Examples 33-61.

[0189] Comparative Examples 10-18: This comparative example provides an organic electroluminescent device. The only difference between the preparation method of this organic electroluminescent device and that of Device Example 32 is that the organic electroluminescent device uses the existing comparative compound ai instead of the light-emitting auxiliary material (compound 1) in Device Example 32 for vapor deposition.

[0190] The driving voltage, luminous efficiency, and lifetime of the organic electroluminescent devices obtained in Examples 32-61 and Comparative Examples 10-18 were characterized at a brightness of 15000 nits. The test results are shown in Table 3 below.

[0191] Table 3

[0192]

[0193]

[0194] As can be seen from Tables 2 and 3, the performance of both green and red light-emitting devices can be altered by changing the connection position, changing the substituents, and varying the position of the substituents. Compared with organic electroluminescent devices prepared using the luminescent auxiliary materials provided in this application, the organic electroluminescent devices prepared using the comparative compounds exhibit improved efficiency and lifetime.

[0195] Comparative compounds a and b, and compounds 47 and 48, are parallel comparative examples. The difference lies in the following: in this application, the triarylamine N atom is attached to dibenzofuran, while in comparative compounds a and b, it is attached to dibenzothiophene. Due to the different electronegativity of O and S, the HOMO and LUMO values ​​of the compounds are distributed differently. Moreover, dibenzofuran is relatively more electrochemically stable, which is more conducive to improving the migration rate of the compound. When used in devices, it can reduce the hole transport barrier and improve luminous efficiency.

[0196] Comparative compounds d and 1 are parallel comparative examples, the difference being that comparative compound d is linked to 9,9-dimethylfluorene, while the compound in this application is linked to 9-alkyl-9-phenylfluorene. In the compounds of this application, compared to comparative compound d, compound 1 appropriately increases the molecular weight of the compound without increasing the conjugation system of the triarylamine, making the compound more stable and avoiding the possibility of compound decomposition due to increased deposition temperature during long-term deposition processes, thereby improving device lifespan.

[0197] Comparative compounds f and 106 are parallel comparative examples. The difference is that the dibenzofuran in comparative compound f does not have any other substituents attached, while the dibenzofuran in this application has diphenyl attached as a substituent, which prolongs the conjugated system of the compound, avoids carrier migration localization, and thus reduces the driving voltage.

[0198] Comparative compounds g and 49 are parallel comparative examples. The difference is that in comparative compound g, one side of the triarylamine N atom is attached to 9,9-diphenylfluorene, while in this application, the side of the triarylamine N atom attached to the compound contains dibenzofuran, which is an electron-withdrawing group that increases the migration rate of the compound. When used in a device, it can reduce the hole transport barrier and improve the luminous efficiency.

[0199] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. 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 this application. Therefore, this application 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 luminescent auxiliary material, characterized in that, The general structural formula of the luminescent auxiliary material is shown in chemical formula I: R1, R2, and R3 are independently selected from substituted or unsubstituted C6-C30 aryl and substituted or unsubstituted C6-C30 heteroaryl, respectively, and the heteroatom is at least one of O, S, N, Si, and Se. Ar is independently selected from the following groups: 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 the heteroatom is at least one of O, S, N, Si, and Se. R5 is selected from substituted or unsubstituted C6-C12 aryl groups or substituted or unsubstituted C6-C12 heteroaryl groups, wherein the heteroatom is at least one of O, S, N, Si, or Se. m is 0 or 1; s and t are selected from 0 or 1, and s and t are not both 0 at the same time.

2. The luminescent auxiliary material according to claim 1, characterized in that, R1, R2, and R3 are each independently selected from phenyl, biphenyl, or naphthyl groups; R4 is selected from hydrogen, methyl, phenyl, naphthyl, or biphenyl; R5 is selected from phenyl, naphthyl, or biphenyl.

3. The luminescent auxiliary material according to claim 1, characterized in that, The general structural formula of the luminescent auxiliary material is either chemical formula I-1 or chemical formula I-2: Where s and t are selected from 1.

4. A method for preparing the luminescent auxiliary material as described in claim 1, characterized in that, Specifically, the steps include the following: 1) Dissolve raw material A and raw material B in a mixed solution of toluene, ethanol and water respectively. Then slowly add the raw material B solution to the raw material A solution. Under nitrogen protection, add potassium carbonate and tetra(triphenylphosphine)palladium and stir until homogeneous. Heat to 80℃-120℃ and reflux for 4-12 hours to obtain intermediate 1. 2) Dissolve intermediate 1 in tetrahydrofuran solution, slowly add n-butyllithium and react for 2 hours, then slowly add benzaldehyde dropwise and stir until homogeneous, and continue the reaction for 4-12 hours to obtain intermediate 2. 3) Dissolve intermediate 2 in DCM, add boron trifluoride diethyl ether and react for 0.2-2 h to obtain intermediate 3; 4) Dissolve intermediate 3 in THF, slowly add t-BuOK and stir for 1 hour, then slowly add CH3I dropwise, heat to 70-90℃ and react for 8-12 hours to obtain intermediate 4; 5) Dissolve intermediate 4 in toluene and raw material E in toluene. Then slowly add the raw material E solution to the intermediate 4 solution. Under nitrogen protection, add tris(dibenzylacetone)palladium, tri-tert-butylphosphine and sodium tert-butoxide. Stir until homogeneous and heat to 100℃-120℃ for 1-4 hours to obtain intermediate 5. 6) Dissolve intermediate 5 in toluene and raw material F in toluene. Then slowly add the raw material F solution to the intermediate 5 solution. Under nitrogen protection, add tris(dibenzylacetone)dipalladium, tri-tert-butylphosphine and sodium tert-butoxide. Stir until homogeneous and heat to 110℃-120℃ for 8-12 hours to obtain the luminescent auxiliary material as shown in chemical formula I. The structural formulas of raw materials A, B, E, and F are shown below: Hal is selected independently from chlorine, bromine, or iodine.

5. An organic electroluminescent device, characterized in that, The organic electroluminescent device includes the light-emitting auxiliary material as described in any one of claims 1-3.

6. The organic electroluminescent device according to claim 5, characterized in that, The organic electroluminescent device includes a light-emitting auxiliary layer; the light-emitting auxiliary layer includes the aforementioned light-emitting auxiliary material.

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