A light-emitting auxiliary material, its preparation method and organic electroluminescent device

Abstract

The present invention discloses a luminescent auxiliary material, a preparation method thereof and an organic electroluminescent device. The general structural formula thereof is chemical formula I: The present invention provides a luminescent auxiliary material having a high glass transition temperature, which can effectively improve the life and luminous efficiency of OLED devices while reducing the driving voltage through device structure optimization.

Description

Technical Field

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

[0002] Organic electroluminescent (OLED) device technology can be used to manufacture new display products and new lighting products. It is expected to replace existing liquid crystal displays and fluorescent lighting, and has a wide range of applications. Organic electrical components that use organic light-emitting phenomena usually have an anode, a cathode, and an organic layer between them. In order to improve the efficiency and stability of organic electrical components, the organic layer is usually composed of a multilayer structure composed of various different substances.

[0003] OLED optoelectronic functional materials used in OLED devices can be divided into two categories based on their uses, namely charge injection transport materials and luminescent materials. Furthermore, charge injection transport materials can be divided into electron injection transport materials, electron blocking materials, hole injection transport materials and hole blocking materials, and luminescent materials can be divided into main luminescent materials and doping materials.

[0004] The hole transport layer (HTL) is responsible for regulating the injection speed and injection amount of holes, and in the OLED, copper phthalocyanine (CuPc), 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (NPB), N,N'-diphenyl-N,N'-bis(3-methylphenyl)-(1,1'-biphenyl)-4,4'-diamine (TPD), 4,4',4"-tris(3-methylphenylphenylamino)triphenylamine (MTDATA), etc. are often used as compounds contained in the hole transport region. However, OLEDs using these materials have problems in quantum efficiency and service life. This is because when the OLED is driven at a high current, thermal stress occurs between the anode and the hole injection layer, and the thermal stress significantly reduces the service life of the device. In addition, since the organic material used in the hole transport region has a very high hole mobility, the hole-electron charge balance may be destroyed and the quantum efficiency (cd / A) may be reduced.

[0005] Therefore, in order to solve the above problems, a luminescent auxiliary layer is usually added between the hole transport layer and the light-emitting layer (i.e., a multi-layer hole transport layer is set) to improve the life and efficiency of the device. The luminescent auxiliary layer can reduce the barrier between the hole transport layer and the light-emitting layer, reduce the driving voltage of the organic electroluminescent device, and further increase the utilization rate of holes, thereby improving the luminous efficiency and life of the device and reducing the driving voltage. However, there are few functional materials that can form a luminescent auxiliary layer. In particular, the life and luminous efficiency of OLEDs are not significantly improved, and the glass transition temperature is low. Therefore, it is particularly important to develop higher performance organic functional materials to meet the requirements of panel manufacturers. Summary of the invention

[0006] In view of this, the present invention provides a luminescent auxiliary material having a relatively high glass transition temperature, which can effectively improve the lifespan and luminous efficiency of OLED devices while reducing the driving voltage through device structure optimization.

[0007] In order to achieve the above object, the present invention adopts the following technical solution:

[0008] A luminescence auxiliary material, the general structural formula of which is chemical formula I:

[0009]

[0010] in,

[0011] X is selected from any one of O, S, -C(R1)(R2)-, -NR3;

[0012] R1-R3 each independently represents a substituted or unsubstituted C1-C12 alkyl group, a substituted or unsubstituted C6-C18 aryl group, or a substituted or unsubstituted 3- to 30-membered heteroaryl group;

[0013] R represents a substituted or unsubstituted C1-C10 alkyl group, a substituted or unsubstituted C6-C30 aryl group, or a substituted or unsubstituted 3- to 30-membered heteroaryl group;

[0014] Ar1 and Ar2 each independently represent a substituted or unsubstituted C3-C20 cycloalkyl group, a substituted or unsubstituted 3-30-membered heterocycloalkyl group, wherein the heteroatom is one or any combination of N, O, S, Si, P and Se; a substituted or unsubstituted C6-C30 aryl group, a substituted or unsubstituted 3-20-membered heteroaryl group, wherein the heteroatom is one or any combination of N, O, S, Si, P or Se, a C1-C10 alkoxy group, a C6-C20 arylamino group; a substituted or unsubstituted C10-C30 fused ring group, a substituted or unsubstituted C5-C30 spirocyclic group.

[0015] Preferably, X is O or S.

[0016] Preferably, said R1-R3 each independently represents methyl, ethyl, phenyl, biphenyl, methylbenzene, naphthyl, biphenyl.

[0017] Preferably, R represents hydrogen, methyl, ethyl, tert-butyl, methylbenzene, methoxy, phenyl, naphthyl, biphenyl, phenanthryl, carbazolyl, fluorenyl, dimethylfluorene, terphenyl, benzofuran, benzothiophene, or pyridyl.

[0018] Preferably, Ar1 and Ar2 are connected to N at any connectable position, and Ar1 and Ar2 each independently represent the following groups:

[0019]

[0020] Preferably, the general structural formula of the luminescence auxiliary material is chemical formula Ia:

[0021]

[0022] wherein R, Ar1, and Ar2 are the same as defined above.

[0023] Preferably, the light-emitting auxiliary material is any one of the following structures:

[0024]

[0025]

[0026]

[0027]

[0028]

[0029] The present invention also provides a method for preparing the above-mentioned luminescence auxiliary material, comprising the following steps:

[0030]

[0031] Step 1:

[0032] Under N2 protection, 1.0 eq of intermediate A-1, 1-1.2 eq of reactant B-1, 0.01-0.02 eq of tetrakis(triphenylphosphine)palladium and 2.1-2.3 eq of potassium carbonate were added to a mixed solvent of toluene, ethanol and water in a volume ratio of 2-4:1:1, respectively, and the temperature was raised to 100-120°C, and the reaction was carried out for 8-12 hours. After the reaction was completed, the mixture was cooled to room temperature, and after the solid was precipitated, it was filtered by suction, and then washed with water to remove the salt, and then rinsed with a small amount of ethanol, the filter cake was dried, and recrystallized in 1,4-dioxane to obtain the compound represented by intermediate C-1;

[0033] Step 2:

[0034] After adding 1.0eq of intermediate C-1 and 1.0-1.4eq of reactant D-1 to a reaction vessel and dissolving them in toluene, 0.01eq of Pd2(dba)3, 0.02-0.04eq of P(t-Bu)3, and 1.5-3.0eq of t-BuONa are added under a nitrogen atmosphere; after the addition, the reaction temperature is slowly raised to 105-115°C, and the mixture is stirred for 8-12h; diatomaceous earth is used for hot filtration to remove salt and catalyst, and after the filtrate is cooled to room temperature, distilled water is then added to the filtrate for washing, and after separation, the organic phase is retained, and the aqueous phase is extracted with ethyl acetate; the combined organic layer is then dried with magnesium sulfate, and the solvent is removed with a rotary evaporator; the remaining substance is purified by column chromatography using a dichloromethane: petroleum ether volume ratio of 1:(1-9) as an eluent to obtain a compound intermediate E-1;

[0035] Step 3:

[0036] After adding 1.0eq of intermediate E-1 and 1.0-1.4eq of reactant F-1 to a reaction vessel and dissolving them in toluene, 0.01eq of Pd2(dba)3, 0.02-0.04eq of P(t-Bu)3, and 1.5-2.5eq of t-BuONa are added under a nitrogen atmosphere; after the addition, the reaction temperature is slowly raised to 105-115°C, and the mixture is stirred for 8-12h; diatomaceous earth is used for hot filtration to remove salt and catalyst, and after the filtrate is cooled to room temperature, distilled water is then added to the filtrate for washing, and after separation, the organic phase is retained, and the aqueous phase is extracted with ethyl acetate; the combined organic layer is then dried with magnesium sulfate, and the solvent is removed with a rotary evaporator; the remaining substance is purified by column chromatography using a dichloromethane: petroleum ether volume ratio of 1:(1-9) as an eluent to obtain a compound of general formula 1;

[0037] wherein R, X, Ar1, Ar2 are as defined above; Hal1, Hal2 and Hal3 are selected from chlorine (Cl), bromine (Br), iodine (I).

[0038] The present invention also provides an organic electroluminescent device, comprising a luminescent auxiliary layer composed of the luminescent auxiliary material described above.

[0039] In the above terms of the present invention, "substitution" means that the hydrogen atom bonded to the carbon atom of the compound is changed into another substituent, and the position of substitution is not limited as long as the position is the position where the hydrogen atom is substituted (i.e., the position where the substituent can be substituted), and when two or more substituents are substituted, the two or more substituents can be the same or different from each other. 3-membered to 10-membered heteroaryl, the heteroatom in the heteroaryl is selected from one or more of N, S, O, Si, P or Se, C1-C10 alkoxy, C6-C20 arylamino;

[0040] In the above terms of the present invention, "slow heating" means adjusting the heating rate according to actual operating conditions, and its slowness is conducive to sufficient reaction and smooth reaction.

[0041] It can be seen from the above technical solution that, compared with the prior art, the beneficial effects of the present invention are:

[0042] The present invention provides an organic electroluminescent compound for a blue light emitting auxiliary layer having excellent performance, which is obtained by connecting a benzonaphthofuran or benzonaphthothiophene skeleton with an aromatic amine group through a phenyl group. The prepared device has the characteristics of high luminous efficiency, low driving voltage and long service life.

[0043] The aromatic amine group in the compound of the present invention enables it to have a strong hole transport ability. The mono-triarylamine structure can reduce the crystallinity of the molecule, reduce the planarity of the molecule, and prevent the molecule from moving on the plane. At the same time, the high hole transport rate can reduce the driving voltage of the device and improve the efficiency and life of the organic electroluminescent device.

[0044] Benzonaphthofuran or benzonaphthothiophene has a rigid planar structure, and the symmetry of the molecule is further reduced by the phenyl group with a bridging π group, which increases the conformational isomers of the molecule, making the compound difficult to crystallize and aggregate, having good film-forming properties and thermal stability, and having a high glass transition temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0046] Figure 1 is the hydrogen nuclear magnetic resonance spectrum of compound 6 in Example 1 of the present invention;

[0047] Figure 2 is the hydrogen nuclear magnetic resonance spectrum of compound 22 in Example 2 of the present invention;

[0048] Figure 3 This is the hydrogen nuclear magnetic resonance spectrum of compound 51 in Example 3 of the present invention. DETAILED DESCRIPTION

[0049] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0050] Example 1: Synthesis of Compound 6

[0051]

[0052] Step 1:

[0053] Under N2 protection, intermediate A-6 (50mmol), reactant B-6 (60mmol), tetrakis(triphenylphosphine)palladium (0.5mmol) and potassium carbonate (110mmol) were added to a mixed solvent of toluene (300mL), ethanol (100mL) and water (100ml), respectively, and the temperature was raised to 100°C, and the reaction was carried out for 8h. After the reaction was completed, it was cooled to room temperature, and after the solid was precipitated, it was filtered and washed with water to remove the salt, and then rinsed with a small amount of ethanol, and the filter cake was dried. It was placed in 1,4-dioxane for recrystallization to obtain the compound shown in intermediate C-6 (9.0g, Ms: 200.40, yield: 90%).

[0054] Step 2:

[0055] After adding intermediate C-6 (40mmol) and reactant D-6 (48mmol) dissolved in toluene to the reaction vessel, Pd2(dba)3 (0.4mmol), P(t-Bu)3 (0.8mmol), t-BuONa (80mmol) were added under nitrogen atmosphere. After addition, the reaction temperature was slowly raised to 110°C, and the mixture was stirred for 10h. Celite was used for hot filtration to remove salts and catalysts. After the filtrate was cooled to room temperature, distilled water was then added to the filtrate for washing. After separation, the organic phase was retained and the aqueous phase was extracted with ethyl acetate. The combined organic layer was then dried with magnesium sulfate, and the solvent was removed using a rotary evaporator. The remaining substance was purified by column chromatography using a dichloromethane: petroleum ether volume ratio of 1: (1-9) as the eluent to obtain compound intermediate E-6 (16.4g, Ms: 501.46, yield: 82%).

[0056] Step 3:

[0057] After adding intermediate E-6 (28mmol) and reactant F-6 (33.6mmol) to the reaction vessel and dissolving in toluene, Pd2(dba)3 (0.028mmol), P(t-Bu)3 (0.56mmol), and t-BuONa (56mmol) were added under a nitrogen atmosphere. After addition, the reaction temperature was slowly raised to 110°C, and the mixture was stirred for 8h. Celite was used for hot filtration to remove salts and catalysts. After the filtrate was cooled to room temperature, distilled water was then added to the filtrate for washing. After separation, the organic phase was retained and the aqueous phase was extracted with ethyl acetate. The combined organic layer was then dried with magnesium sulfate, and the solvent was removed using a rotary evaporator. The remaining substance was purified by column chromatography using a dichloromethane: petroleum ether volume ratio of 1: (1-9) as the eluent to obtain compound 6 (18.6g, yield: 88%).

[0058] The yield in each of the above steps is the fractional yield of the corresponding step.

[0059] Characterization:

[0060] HPLC purity: >99.6%.

[0061] Mass spectrometry test: theoretical value is 753.95; tested value is 754.11.

[0062] Elemental Analysis:

[0063] Theoretical values: C, 90.81; H, 5.21; N, 1.86; O, 2.12

[0064] Test values: C, 90.95; H, 5.38; N, 1.57; O, 2.30

[0065] H NMR spectrum: as attached Figure 1 shown.

[0066] Example 2: Synthesis of Compound 22

[0067]

[0068] Step 1:

[0069] The reaction is exactly the same as intermediate C-6.

[0070] Step 2:

[0071] After adding intermediate C-22 (40mmol) and reactant D-22 (48mmol) to the reaction vessel and dissolving in toluene, Pd2(dba)3 (0.4mmol), P(t-Bu)3 (0.8mmol), t-BuONa (80mmol) were added under nitrogen atmosphere. After addition, the reaction temperature was slowly raised to 110°C, and the mixture was stirred for 10h. Celite was used for hot filtration to remove salts and catalysts. After the filtrate was cooled to room temperature, distilled water was then added to the filtrate for washing. After separation, the organic phase was retained and the aqueous phase was extracted with ethyl acetate. The combined organic layer was then dried with magnesium sulfate, and the solvent was removed using a rotary evaporator. The remaining substance was purified by column chromatography using a dichloromethane: petroleum ether volume ratio of 1: (1-9) as the eluent to obtain compound intermediate E-22 (14.8g, yield: 85%, Ms: 435.62).

[0072] Step 3:

[0073] After adding intermediate E-22 (28 mmol) and reactant F-22 (33.6 mmol) to the reaction vessel and dissolving in toluene, Pd2(dba)3 (0.028 mmol), P(t-Bu)3 (0.56 mmol), and t-BuONa (56 mmol) were added under a nitrogen atmosphere. After addition, the reaction temperature was slowly raised to 110°C, and the mixture was stirred for 8 hours. Celite was used for hot filtration to remove salts and catalysts. After the filtrate was cooled to room temperature, distilled water was then added to the filtrate for washing. After separation, the organic phase was retained and the aqueous phase was extracted with ethyl acetate. The combined organic layer was then dried with magnesium sulfate, and the solvent was removed using a rotary evaporator. The remaining substance was purified by column chromatography using a dichloromethane: petroleum ether volume ratio of 1: (1-9) as the eluent to obtain compound 22 (15.2 g, yield: 80%).

[0074] The yield in each of the above steps is the fractional yield of the corresponding step.

[0075] Characterization:

[0076] HPLC purity: >99.8%.

[0077] Mass spectrometry test: theoretical value is 677.55; tested value is 677.84.

[0078] Elemental Analysis:

[0079] Theoretical values: C, 88.60; H, 4.61; N, 2.07; O, 4.72

[0080] Test values: C, 88.30; H, 4.82; N, 2.12; O, 4.86

[0081] H NMR spectrum: as attached Figure 2 shown.

[0082] Example 3: Synthesis of Compound 51

[0083]

[0084] Step 1:

[0085] The reaction is exactly the same as intermediate C-6.

[0086] Step 2:

[0087] The reaction is exactly the same as intermediate E-6.

[0088] Step 3:

[0089] After adding intermediate E-51 (28 mmol) and reactant F-51 (33.6 mmol) to the reaction vessel and dissolving in toluene, Pd2(dba)3 (0.028 mmol), P(t-Bu)3 (0.56 mmol), and t-BuONa (56 mmol) were added under a nitrogen atmosphere. After addition, the reaction temperature was slowly raised to 110°C, and the mixture was stirred for 8 hours. Celite was used for hot filtration to remove salts and catalysts. After the filtrate was cooled to room temperature, distilled water was then added to the filtrate for washing. After separation, the organic phase was retained and the aqueous phase was extracted with ethyl acetate. The combined organic layer was then dried with magnesium sulfate, and the solvent was removed using a rotary evaporator. The remaining substance was purified by column chromatography using a dichloromethane: petroleum ether volume ratio of 1: (1-9) as an eluent to obtain compound 51 (17.3 g, yield: 83%).

[0090] The yield in each of the above steps is the fractional yield of the corresponding step.

[0091] Characterization:

[0092] HPLC purity: >99.7%.

[0093] Mass spectrometry test: theoretical value is 742.92; tested value is 743.15.

[0094] Elemental Analysis:

[0095] Theoretical values: C, 88.92; H, 5.16; N, 3.77; O, 2.15

[0096] Test values: C, 88.85; H, 5.23; N, 3.69; O, 2.33

[0097] H NMR spectrum: as attached Figure 3 shown.

[0098] Example 4-Example 58

[0099] The following compounds were synthesized by referring to the synthesis methods of Examples 1 to 3. The mass spectra, molecular formulas and yields are shown in Table 1 below.

[0100] Table 1:

[0101]

[0102]

[0103]

[0104] In addition, it should be noted that other compounds of the present application can be obtained by referring to the synthesis methods of the above-listed embodiments, so they will not be listed one by one here.

[0105] The present invention provides an organic electroluminescent device, comprising a first electrode, a second electrode opposite to the first electrode, and one or more organic layers between the first electrode and the second electrode, wherein at least one of the organic layers contains the compound represented by formula I prepared by the present invention.

[0106] The organic light-emitting element of the present invention may have a structure including a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting auxiliary layer, a light-emitting layer, a hole blocking layer, an electron transport layer, an electron injection layer, etc. as organic layers. However, the structure of the organic light-emitting element is not limited thereto, and may include fewer or more organic layers.

[0107] According to one embodiment of the present specification, the organic layer comprises a light-emitting auxiliary layer, and the light-emitting auxiliary layer comprises the compound represented by formula I prepared by the present invention.

[0108] When the organic light emitting element includes a plurality of organic layers, the organic layers may be formed of the same substance or different substances.

[0109] Regarding the compound represented by the above chemical formula I, when manufacturing an organic light-emitting device, a true

[0110] In addition to the air vapor deposition method, the organic layer can also be formed by a solution coating method, wherein the solution coating method includes spin coating, dip coating, blade coating, inkjet printing, screen printing, spraying, roll coating, etc., but is not limited to these.

[0111] The organic light emitting element of the present invention may be a top emission type, a bottom emission type or a bi-directional emission type depending on the materials used.

[0112] The device of the present invention can be used in organic light-emitting devices, organic solar cells, electronic paper, organic photoreceptors or organic thin film transistors.

[0113] The present invention provides a method for preparing an organic electroluminescent device, comprising:

[0114] [Application Example 1] Preparation of organic electroluminescent devices:

[0115] a. ITO anode: Wash the ITO (indium tin oxide)-Ag-ITO (indium tin oxide) glass substrate with a coating thickness of 150nm in distilled water twice, ultrasonically wash for 30 minutes, and then repeatedly wash it with distilled water twice, ultrasonically wash for 10 minutes. After washing, transfer it to a spin dryer for drying, and finally bake it in a vacuum oven at 220℃ for 2 hours. After baking, cool it down and it can be used. Use this substrate as the anode, use an evaporation machine to carry out the evaporation device process, and evaporate other functional layers on it in sequence.

[0116] b. HIL (hole injection layer): The hole injection layer materials HT and P-dopant are vacuum evaporated at a deposition rate of 98:2, and the thickness is 10 nm;

[0117] c. HTL (hole transport layer): At a deposition rate of 100%, 120 nm of HT was vacuum-deposited on the hole injection layer as a hole transport layer.

[0118] d. Light-emitting auxiliary layer: At a deposition rate of , 10 nm of the compound 1 provided in the above embodiment is vacuum-deposited on the hole transport layer as a light-emitting auxiliary layer;

[0119] e. EML (light-emitting layer): Then on the above-mentioned light-emitting auxiliary layer, The host material (Host) and dopant material (Dopant) with a thickness of 25nm are vacuum-deposited as the light-emitting layer. The chemical formulas of Host and Dopant are shown below. The evaporation rate ratio of Host to Dopant is 97:3.

[0120] f. ETL (Electron Transport Layer): ET and Liq were vacuum-deposited at a deposition rate of 35 nm as an electron transport layer, and the chemical formula of ET is shown below. The deposition rate ratio of ET to Liq is 50:50.

[0121] g. EIL (electron injection layer): At a evaporation rate of , a 1.0 nm Yb film layer was evaporated to form an electron injection layer.

[0122] h. Cathode: The evaporation rate ratio is 1:9, and magnesium and silver are evaporated at 18nm, and the evaporation rate ratio is 1:9 to obtain an OLED device.

[0123] i. Light extraction layer: At a deposition rate of , CPL with a thickness of 70 nm was vacuum-deposited on the cathode as a light extraction layer.

[0124] j. Package the substrate after evaporation. First, use the glue coating equipment to coat the cleaned cover with UV glue, then move the coated cover to the pressing section, place the evaporation-deposited substrate on the upper end of the cover, and finally bond the substrate and cover with the bonding equipment, and complete the light curing of the UV glue.

[0125] Device structure:

[0126] ITO / Ag / ITO / HT:P-dopant(10nm,2%) / HT(120nm) / Compound 1(10nm) / Host:Dopant(25nm,3%) / ET:Liq(35nm,50%) / Yb(1nm) / Mg:Ag(18nm,1:9) / CPL(70nm).

[0127]

[0128] Application Example 2-58

[0129] The organic electroluminescent devices of Application Examples 2-58 were prepared according to the above-mentioned method for preparing an organic electroluminescent device, except that the compound 1 in Application Example 1 was replaced by the corresponding compound 2-58 to form a light-emitting auxiliary layer.

[0130] Comparative Example 1

[0131] An organic electroluminescent device was prepared according to the above-mentioned method for preparing an organic electroluminescent device, except that the compound 1 in Application Example 1 was replaced by a comparative compound 1, wherein the structural formula of the comparative compound 1 is as follows:

[0132]

[0133] Comparative Example 2

[0134] An organic electroluminescent device was prepared according to the above-mentioned method for preparing an organic electroluminescent device, except that the compound 1 in Application Example 1 was replaced by a comparative compound 2, wherein the structural formula of the comparative compound 2 is as follows:

[0135]

[0136] Comparative Example 3

[0137] An organic electroluminescent device was prepared according to the above-mentioned method for preparing an organic electroluminescent device, except that the compound 1 in Application Example 1 was replaced by a comparative compound 3, wherein the structural formula of the comparative compound 3 is as follows:

[0138]

[0139] Comparative Example 4

[0140] An organic electroluminescent device was prepared according to the above-mentioned method for preparing an organic electroluminescent device, except that the compound 1 in Application Example 1 was replaced by a comparative compound 4, wherein the structural formula of the comparative compound 4 is as follows:

[0141]

[0142] Comparative Example 5

[0143] An organic electroluminescent device was prepared according to the above-mentioned method for preparing an organic electroluminescent device, except that the compound 1 in Application Example 1 was replaced by a comparative compound 5, wherein the structural formula of the comparative compound 5 is as follows:

[0144]

[0145] Comparative Example 6

[0146] An organic electroluminescent device was prepared according to the above-mentioned method for preparing an organic electroluminescent device, except that the compound 1 in Application Example 1 was replaced by a comparative compound 5, wherein the structural formula of the comparative compound 5 is as follows:

[0147]

[0148] The driving voltage, luminous efficiency, BI value and life of the organic electroluminescent devices obtained from the above device embodiments 1 to 58 and device comparative examples 1 to 6 were characterized at a brightness of 1000 (nits). The test results are shown in Table 2 below:

[0149] Table 2 Luminous characteristics test results (brightness: 1000nits)

[0150]

[0151]

[0152]

[0153] As can be seen from the above table, the performance of the light-emitting auxiliary material devices used in Comparative Examples 1-6 and Application Examples 1-58 has been improved in terms of life, luminous efficiency, and BI value. The driving voltage has also been improved. This shows that the organic electroluminescent device prepared using the compound provided by the present invention as the light-emitting auxiliary material exhibits a high BI value, long life, and low voltage.

[0154] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

[0155] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0156] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be 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 invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A luminescent auxiliary material, characterized in that: Its structural formula is selected from any one of the following molecular formulas:

2. An organic electroluminescent device, characterized in that: It comprises a luminescence-assisting layer composed of the luminescence-assisting material according to claim 1.

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