Organic electroluminescent element

Abstract

The present invention relates to an organic electroluminescent element. The organic electroluminescent element includes an anode, a cathode, a hole injection layer, a hole transport layer, a light-emitting layer and an electron transport layer, and the electron transport layer includes a quinoxaline triazine compound and a bistriazine compound, wherein the quinoxaline triazine compound is any one of the compounds represented by chemical formula A1 or A2, and the bistriazine compound has a chemical formula B: the quinoxaline triazine compound with chemical formula A1 or A2 helps to improve the life of the organic electroluminescent device, and the bistriazine compound with chemical formula B1 or chemical formula B helps to reduce the driving voltage of the organic electroluminescent device and improve the device efficiency. The present application uses the above-mentioned quinoxaline triazine compound and the bistriazine compound in a mixed manner, comprehensively utilizes the advantages of the two, and alleviates the disadvantages of the two to the organic electroluminescent device, thereby obtaining an organic electroluminescent device with high efficiency, high life and low driving voltage.

Description

Technical Field

[0001] The present invention relates to the technical field of organic electroluminescence, and in particular to an organic electroluminescence element. Background Art

[0002] Organic electroluminescent elements (OLEDs) have been used in smart phones, tablet computers, and automotive applications due to their light weight, wide viewing angle, high contrast, low power consumption, high response speed, full-color display, and flexibility, and are expanding to large-size applications such as televisions.

[0003] For organic light-emitting diodes to achieve full-color displays, the performance of blue light devices is key. Organic electroluminescent elements usually include multiple film layers such as hole injection layer, hole transport layer, electron blocking layer, light-emitting layer, hole blocking layer, electron transport layer, electron injection layer, etc. The glass transition temperature of the film layer, the energy level matching between the film layers, the film formation quality and stability of the film layer will affect the performance of the element. The performance of the electron transport layer material determines the transmission efficiency of electrons, and further affects the combination efficiency of electrons and holes in the light-emitting layer. Therefore, the electron transport layer is a key film layer that affects the performance of the device. However, due to the limitations of the electron transport layer in actual applications, it is difficult for organic electroluminescent elements to have high efficiency, high life and low driving voltage. Summary of the invention

[0004] The main purpose of the present invention is to provide an organic electroluminescent element to solve the problem in the prior art that it is difficult for organic electroluminescent devices to have high efficiency, long life and low driving voltage.

[0005] In order to achieve the above object, according to one aspect of the present invention, an organic electroluminescent element is provided, the organic electroluminescent element comprising an anode, a cathode, a hole injection layer, a hole transport layer, a light-emitting layer and an electron transport layer, the electron transport layer comprising a quinoxaline-triazine compound and a bistriazine compound, the quinoxaline-triazine compound is any one of the compounds represented by chemical formula A1 or A2, and the bistriazine compound has a chemical formula B:

[0006]

[0007] Furthermore, the mass ratio of the quinoxaline-triazine compound to the bistriazine compound is 3-7:7-3.

[0008] Furthermore, the hole injection layer comprises one or more arylamine compounds and one or more radium derivatives, wherein the radium derivatives are doped in the arylamine compounds.

[0009] Among them, the arylamine compound has the general formula I: wherein Ar1, Ar2, Ar3, and Ar4 are each independently selected from substituted or unsubstituted C6 to C 30 aryl, substituted or unsubstituted C5~C 30 Any one of the heteroaryl groups, preferably Ar1 and Ar2, Ar3 and Ar4 are each independently connected by a single bond, a substituted or unsubstituted methylene, an oxygen atom or a sulfur atom;

[0010] The radialene derivatives have the general formula II: Wherein Ar5 is a C6~C 18 The electron withdrawing group is preferably fluorine or cyano.

[0011] Furthermore, in the above general formula I, Ar1, Ar2, Ar3, and Ar4 are each independently selected from substituted or unsubstituted C6 to C 12 Aryl, substituted or unsubstituted C 10 ~C 15 Any one of the heteroaryl groups, further, preferably Ar1, Ar2, Ar3, Ar4 are each independently selected from any one of substituted or unsubstituted phenyl, biphenyl, naphthyl, fluorenyl, and carbazolyl.

[0012] Furthermore, in the above general formula II, Ar5 is a C6-C 12 Ar5 is preferably a mono-substituted or poly-substituted phenyl group, or a mono-substituted or poly-substituted biphenyl group, and each substituent is independently a cyano group or a F atom.

[0013] Furthermore, the mass ratio of the arylamine compound to the radialene derivative is 100:2-20, and further preferably 100:2-8.

[0014] Furthermore, along the direction away from the hole injection layer, the hole transport layer includes a first hole transport layer and a second hole transport layer stacked in sequence, and preferably the first hole transport layer includes any one or more aromatic amine compounds.

[0015] Furthermore, the light-emitting layer is composed of a mixture of at least one main matrix and at least one guest dopant.

[0016] Furthermore, the above-mentioned main matrix is ​​an anthracene compound represented by the general formula BH:

[0017]

[0018] wherein R1 and R2 are the same or different from each other, and R1 and R2 are each independently selected from hydrogen, substituted or unsubstituted C1-C6 alkyl, C1-C6 alkoxy, C6-C 30Aryl, C6~C 30 Any one or more of the heteroaryl groups; Ar6 and Ar7 are each independently selected from C6 to C 30 Aryl or C6~C 30 a, b, and c are each independently an integer of 1 to 4.

[0019] Furthermore, the guest dopant is a fluorescent dye represented by the general formula BD,

[0020]

[0021] Among them, R3 to R 10 are independently selected from a hydrogen atom, a halogen atom, a substituted or unsubstituted C1-C4 alkyl group, a substituted or unsubstituted C3-C 10 cycloalkyl, substituted or unsubstituted silyl, cyano, substituted or unsubstituted C6~C 30 Any one of the aryl groups; Ar8 to Ar 11 Each independently selected from substituted or unsubstituted C6 to C 30 aryl, substituted or unsubstituted C5~C 30 Any one of the heteroaryl groups.

[0022] By applying the technical solution of the present invention, the quinoxaline-triazine compound with chemical formula A1 or A2 helps to increase the life of the organic electroluminescent device, and the bistriazine compound with chemical formula B1 or chemical formula B helps to reduce the driving voltage of the organic electroluminescent device and improve the device efficiency. The present application uses the mixed use of the above-mentioned quinoxaline-triazine compound and the bistriazine compound to comprehensively utilize the advantages of the two and alleviate the disadvantages of the two to the organic electroluminescent device, thereby obtaining an organic electroluminescent device with high efficiency, long life and low driving voltage. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0024] Figure 1 The structure diagram of an organic electroluminescent device provided in Example 1 of the present invention is shown.

[0025] The above drawings include the following reference numerals:

[0026] 1. Anode; 2. Hole injection layer; 3. Hole transport layer; 4. Light-emitting layer; 5. Electron transport layer; 6. Cathode. DETAILED DESCRIPTION

[0027] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0028] As analyzed in the background art, in the prior art, there is a problem that organic electroluminescent devices are difficult to achieve high efficiency, long life and low driving voltage. To solve this problem, the present invention provides an organic electroluminescent element.

[0029] In a typical embodiment of the present application, an organic electroluminescent element is provided, such as Figure 1 As shown, the organic electroluminescent element includes an anode 1, a cathode 6, a hole injection layer 2, a hole transport layer 3, a light-emitting layer 4 and an electron transport layer 5, wherein the electron transport layer 5 includes a quinoxaline-triazine compound and a bistriazine compound, wherein the quinoxaline-triazine compound is any one of the compounds represented by chemical formula A1 or A2, and the bistriazine compound has a chemical formula B:

[0030]

[0031] The quinoxaline-triazine compound with chemical formula A1 or A2 helps to increase the life of the organic electroluminescent device, and the bistriazine compound with chemical formula B1 or chemical formula B helps to reduce the driving voltage of the organic electroluminescent device and improve the device efficiency. The present application uses the above-mentioned quinoxaline-triazine compound and the bistriazine compound in combination, comprehensively utilizes the advantages of the two, and alleviates the disadvantages of the two to the organic electroluminescent device, thereby obtaining an organic electroluminescent device with high efficiency, long life and low driving voltage.

[0032] In order to maximize the synergistic effect of the above-mentioned quinoxaline-triazine compound and the bistriazine compound to obtain an organic electroluminescent device with higher efficiency, longer life and lower driving voltage, the mass ratio of the above-mentioned quinoxaline-triazine compound and the bistriazine compound is preferably 3-7:7-3.

[0033] In one embodiment of the present application, in order to reduce the interface effect between the hole injection layer and the hole transport layer, the hole injection layer preferably includes any one or more arylamine compounds and any one or more radialene derivatives doped therein.

[0034] The arylamine compounds have the general formula I: wherein Ar1, Ar2, Ar3, and Ar4 are each independently a substituted or unsubstituted C6-C 30 Aryl, substituted or unsubstituted C5-C 30 heteroaryl, the substituents on both Ar1 and Ar2, and both Ar3 and Ar4 may be bonded to each other to form a ring via a single bond, a substituted or unsubstituted methylene, an oxygen atom or a sulfur atom;

[0035] The radialene derivatives have the general formula II: Wherein Ar5 is a C6-C 18 The electron withdrawing group is preferably fluorine or cyano.

[0036] The above aromatic amino compound is used as the main body of the hole injection layer to ensure a low interface effect between the hole injection layer and the hole transport layer, and at the same time, the electron-withdrawing ability of the axialene derivative is utilized to improve the injection and transport ability of holes to the light-emitting layer, thereby increasing the recombination probability of holes and electrons.

[0037] In order to further enhance the synergistic effect of the arylamine compounds and the radicalene derivatives, it is preferred that in the above general formula I, Ar1, Ar2, Ar3, and Ar4 are each independently selected from substituted or unsubstituted C6 to C 12 Aryl, substituted or unsubstituted C 10 ~C 15 Any one of the heteroaryl groups, further, preferably Ar1, Ar2, Ar3, Ar4 are each independently selected from any one of substituted or unsubstituted phenyl, biphenyl, naphthyl, fluorenyl, carbazole. Further, preferably, the above-mentioned arylamine compound is selected from any one or more of the following compounds:

[0038]

[0039] In order to further ensure the low interface effect between the hole injection layer and the hole transport layer, it is preferred that in the above general formula II, the above Ar5 is a C6-C 12 Ar5 is a monosubstituted or polysubstituted phenyl group or a monosubstituted or polysubstituted biphenyl group, and each substituent is independently a cyano group or a F atom. Further, the above-mentioned radialene derivative can be selected from any one or more of the following compounds:

[0040]

[0041] In order to achieve a balance between the interface effect and the electron transport capability to obtain a more ideal luminescence efficiency, it is preferred that the mass ratio of the arylamine compound to the radium derivative is 100:2-20, and further, preferably 100:2-8.

[0042] In one embodiment of the present application, in a direction away from the hole injection layer, the hole transport layer includes a first hole transport layer and a second hole transport layer stacked in sequence, and preferably the first hole transport layer includes any one or more aromatic amine compounds.

[0043] The first hole transport layer and the hole injection layer both contain arylamine compounds, so the interface effect between the two is weak. In order to further reduce the interface effect, it is preferred that the arylamine compounds of the two are the same.

[0044] In order to ensure the excellent light-emitting performance of the light-emitting layer, it is preferred that the light-emitting layer is composed of a mixture of at least one host matrix and at least one guest dopant.

[0045] In one embodiment of the present application, the above-mentioned main matrix is ​​an anthracene compound represented by the general formula BH:

[0046]

[0047] wherein R1 and R2 are the same or different from each other, and R1 and R2 are each independently selected from hydrogen, substituted or unsubstituted C1-C6 alkyl, C1-C6 alkoxy, C6-C 30 Aryl, C6~C 30 Any one or more of the heteroaryl groups; Ar6 and Ar7 are each independently selected from C6 to C 30 Aryl or C6~C 30 a, b, c are each independently an integer of 1 to 4. Further, the anthracene derivatives are preferably selected from any one of the following compounds:

[0048]

[0049]

[0050] In order to further improve the luminous efficiency and stability, the guest dopant is preferably a fluorescent dye represented by the general formula BD,

[0051]

[0052] Among them, R3 to R 10 are independently selected from a hydrogen atom, a halogen atom, a substituted or unsubstituted C1-C4 alkyl group, a substituted or unsubstituted C3-C 10 cycloalkyl, substituted or unsubstituted silyl, cyano, substituted or unsubstituted C6~C 30 Any one of the aryl groups; Ar8 to Ar 11 Each independently selected from substituted or unsubstituted C6 to C 30 aryl, substituted or unsubstituted C5~C 30 Further, the fluorescent dye can be selected from any one of the following compounds:

[0053]

[0054]

[0055] The beneficial effects of the present application will be described below in conjunction with specific embodiments and comparative examples.

[0056] 1. Synthesis of Compound A1

[0057]

[0058] 1.1 Synthesis of intermediate M1

[0059] In a three-necked flask, add 4-bromo-o-phenylenediamine (20g, 0.106mol), 2,3-butanedione (9.66g, 0.112mol) and toluene (200ml), and heat under reflux for 3 hours. After the reaction is completed, cool to room temperature, filter with silica gel pad, and evaporate the solvent from the filtrate in vacuum to obtain a crude product. The crude product is dissolved and decolorized with n-hexane and recrystallized to obtain 18.0g of intermediate M1, which is an off-white solid powder with a yield of 71%. The purity is 99.91%.

[0060] 1.2 Synthesis of intermediate M2

[0061] In a three-necked flask, add intermediate I-1 (18.0g, 76mmol), 4-chloro-1-phenylboronic acid (15.68g, 76mmol), potassium carbonate (26.67g, 152mmol), tetrakis-(triphenylphosphine) palladium (0.88g), toluene (300ml), ethanol (76ml) and water (76ml), and heat under reflux for 3 hours under nitrogen protection. After the reaction is completed, cool to room temperature, extract with toluene and water, filter the organic layer with silica gel pad, and vacuum evaporate the filtrate to remove the solvent to obtain a crude product. The crude product is slurried with a mixed solvent of n-hexane / ethanol to obtain 16.34g of intermediate M2, which is an off-white solid powder with a yield of 80% and a purity of 99.30%.

[0062] 1.3 Synthesis of intermediate M3

[0063] In a three-necked flask, add intermediate I-2 (16.34g, 60.8mmol), biboronic acid pinacol ester (18.52g, 72.96mmol) and toluene (300mL), fill with nitrogen and stir for 15 minutes, then add potassium acetate (9.74g, 91.2mmol), tris (dibenzylidene indene acetone) palladium (0.55g), X-Phos (0.55g), and heat under reflux for 7 hours. After the reaction is completed, cool to room temperature, filter with silica gel pad, and evaporate the solvent from the filtrate in vacuo to obtain a crude product. The crude product is slurried with n-hexane / dichloromethane (V:V=10:1) for 1 hour, filtered, and rinsed twice with n-hexane to obtain 17.96g of white solid powder intermediate M3, with a yield of 82% and a purity of 98.9%.

[0064] 1.4 Synthesis of Compound A1

[0065]

[0066] In a three-necked flask, add intermediate I-3 (11.35g, 31.5mmol), 2-chloro-4,6-di(naphthalene-2-yl)-1,3,5-triazine (11.04g, 30mmol), potassium carbonate (12.44g, 90mmol), tetrakis(triphenylphosphine)palladium (0.73g), toluene (300ml), ethanol (45ml) and water (45ml), and heat under reflux for 7 hours under nitrogen protection. After the reaction is completed, cool to room temperature, filter to obtain a crude product, dissolve the crude product in chlorobenzene, pass through silica gel while hot, and then use chlorobenzene to rinse twice, and vacuum evaporate the filtrate to remove the solvent to obtain a crude product. The crude product is refined with chlorobenzene to obtain 17.08g of compound A1 as a white solid powder, with a yield of 70% and a purity of 99.0%. The crude product is purified by vacuum sublimation once, and the purity is 99.92%.

[0067] The characterization results of compound A1 are as follows:

[0068] 1H NMR (400MHz, CDCl3) δ9.40 (s, 2H), 8.99 (d, J = 8.4Hz, 2H), 8.89 (dd, J = 8.6, 1.6Hz, 2H), 8.35 (d, J = 1.7Hz, 1 H),8.19–8.03(m,6H),8.00(d,J=8.4Hz,2H),7.98–7.91(m,2H),7.66–7.54(m,4H),2.78(d,J=2.3Hz,6H).

[0069] 2. Synthesis of Compound A2

[0070]

[0071] In a three-necked flask, add intermediate I-3 (9.45g, 26.25mmol), 2,4-di([1,1'-biphenyl]-4-yl)-6-chloro-1,3,5-triazine (10.60g, 25mmol), potassium carbonate (10.37g, 75mmol), tetrakis(triphenylphosphine)palladium (0.58g), toluene (250ml), ethanol (40ml) and water (40ml), and heat under reflux for 7.5 hours under nitrogen protection. After the reaction is completed, cool to room temperature, filter to obtain a crude product, dissolve the crude product in chlorobenzene, pass through silica gel while hot, and then rinse with chlorobenzene twice. The filtrate is vacuum evaporated to remove the solvent to obtain a crude product, which is refined with chlorobenzene to obtain 8.45g of compound A2 as a white solid powder, with a yield of 55% and a purity of 99.2%. The crude product is purified by vacuum sublimation once, with a purity of 99.89%.

[0072] The characterization results of compound A2 are as follows:

[0073] 1H NMR (400MHz, CDCl3) δ8.82(t,J=8.3Hz,6H),8.27(s,1H),8.02(dd,J=23.9,8.6Hz,2H),7.89(d,J=8 .2Hz,2H),7.77(d,J=8.2Hz,4H),7.68(d,J=7.2Hz,4H),7.44(dt,J=31.3,7.3Hz,6H),2.74(s,6H).

[0074] 3. Synthesis of Compound B

[0075]

[0076] In a three-necked flask, add 2-[3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl]-4,6-diphenyl-1,3,5-triazine (52.23g, 120mmol), 2-(3-bromophenyl)-4,6-diphenyl-1,3,5-triazine (46.59g, 120mmol), potassium carbonate (33.17g, 240mmol), tetrakis(triphenylphosphine)palladium (0.69g), toluene (600ml), ethanol (180ml) and water (120ml), and heat under reflux for 8 hours under nitrogen protection. After the reaction is completed, cool to room temperature, filter to obtain a crude product, dissolve the crude product with chlorobenzene, pass through silica gel while hot, and then rinse with chlorobenzene twice, partially desolventize the filtrate, cool and filter, and obtain 65g of compound B as a white solid powder, with a yield of 88% and a purity of 99.91%. The crude product was purified twice by vacuum sublimation with a purity of 99.95%.

[0077] The characterization results of compound B are as follows:

[0078] 1H NMR (400MHz, CDCl3) δ9.10 (s, 2H), 8.85–8.70 (m, 10H), 8.01–7.89 (m, 2H), 7.69 (t, J = 7.7Hz, 2H), 7.58–7.44 (m, 12H).

[0079] Example 1

[0080] Reference Figure 1The structure of the organic electroluminescent element shown in the figure is manufactured by using a Sunic sp1710 evaporation machine. The specific steps are as follows: a glass substrate (anode 1) (Corning glass 40mm*40mm*0.7mm) coated with ITO (indium tin oxide) with a thickness of 135nm is ultrasonically cleaned with isopropyl alcohol and pure water for 5 minutes respectively, and then cleaned with ultraviolet ozone, and then the glass substrate is transferred to a vacuum deposition chamber; a hole transport material HT1 doped with 4% HD is vacuum-deposited with a thickness of 20nm (about 10 - 7 Torr) is thermally deposited on a transparent ITO electrode to form a hole injection layer 2. Then, a 120nm thick compound HT1 is vacuum deposited on the hole injection layer 2 as the first hole transport layer; then, a 10nm second hole transport layer HT2 is vacuum deposited to form a hole transport layer 3; then, 25nm of BH3 doped with 4% BD4 by mass fraction is vacuum deposited as a light-emitting layer 4; then, a mixture of compound A1, compound B and Liq (mass ratio of 15%:35%:50%) is vacuum deposited to form an electron transport layer 5 with a thickness of 30nm; finally, 2nm thick metal ytterbium (Yb, electron injection layer) and a magnesium-silver alloy doped with a ratio of 10:1 are sequentially deposited to form a cathode 6; finally, the device is transferred from the deposition chamber to a glove box, and then encapsulated with a UV-curable epoxy resin and a glass cover containing a moisture absorbent to obtain an organic electroluminescent element. In the above manufacturing steps, the deposition rates of organic materials, metal ytterbium and metal Mg are maintained at 0.1nm / s, 0.05nm / s and 0.2nm / s respectively. The structure of the organic electroluminescent element is represented as: ITO (135nm) / HT1: 4% HD (20nm) / HT1 (120nm) / HT2 (10nm) / BH3: 4% BD4 (25nm) / A1: B: Liq (15%: 35%: 50%, 30nm) / Yb (2nm) / Mg: Ag (10: 1, 150nm).

[0081] The structural formulas of the above-mentioned HD, HT1, HT2, BH3, BD4 and Liq are as follows:

[0082]

[0083] Example 2

[0084] The difference between Example 2 and Example 1 is that the mass ratio of compound A1, compound B and Liq is 25%:25%:50%, and an organic electroluminescent element is finally obtained. The structure of the organic electroluminescent element is expressed as: ITO (135nm) / HT1:4% HD (20nm) / HT1 (120nm) / HT2 (10nm) / BH3:4% BD4 (25nm) / A1: B: LiQ (25%: 25%: 50%, 30nm) / Yb (2nm) / Mg: Ag (10:1, 150nm).

[0085] Example 3

[0086] The difference between Example 3 and Example 1 is that, as an electron transport layer, compound A2 is used instead of compound A1, and the mass ratio of compound A2, compound B and Liq is 15%:35%:50%. Finally, an organic electroluminescent element is obtained, and the structure of the organic electroluminescent element is expressed as: ITO (135nm) / HT1: 4% HD (20nm) / HT1 (120nm) / HT2 (10nm) / BH3: 4% BD4 (25nm) / A2: B: Liq (15%: 35%: 50%, 30nm) / Yb (2nm) / Mg: Ag (10: 1, 150nm).

[0087] Example 4

[0088] The difference between Example 4 and Example 1 is that, as an electron transport layer, compound A2 is used instead of compound A1, and the mass ratio of compound A2, compound B and Liq is 25%:25%:50%. Finally, an organic electroluminescent element is obtained, and the structure of the organic electroluminescent element is expressed as: ITO (135nm) / HT1: 4% HD (20nm) / HT1 (120nm) / HT2 (10nm) / BH3: 4% BD4 (25nm) / A2: B: Liq (25%: 25%: 50%, 30nm) / Yb (2nm) / Mg: Ag (10: 1, 150nm).

[0089] Comparative Example 1

[0090] The difference between Comparative Example 1 and Example 1 is that compound A1:Liq (50%:50%) is used as an electron transport layer, and an organic electroluminescent element is finally obtained. The structure of the organic electroluminescent element is expressed as: ITO (135nm) / HT1:4% HD (20nm) / HT1 (120nm) / HT2 (10nm) / BH3:4% BD4 (25nm) / A1:Liq (50%:50%, 30nm) / Yb (2nm) / Mg:Ag (10:1, 150nm).

[0091] Comparative Example 2

[0092] The difference between Comparative Example 2 and Example 1 is that compound A2:Liq (50%:50%) is used as an electron transport layer, and an organic electroluminescent element is finally obtained. The structure of the organic electroluminescent element is expressed as: ITO (135nm) / HT1:4% HD (20nm) / HT1 (120nm) / HT2 (10nm) / BH3:4% BD4 (25nm) / A2:Liq (50%:50%, 30nm) / Yb (2nm) / Mg:Ag (10:1, 150nm).

[0093] Comparative Example 3

[0094] The difference between Comparative Example 2 and Example 1 is that compound B:Liq (50%:50%) is used as an electron transport layer, and an organic electroluminescent element is finally obtained. The structure of the organic electroluminescent element is expressed as: ITO (135nm) / HT1:4% HD (20nm) / HT1 (120nm) / HT2 (10nm) / BH3:4% BD4 (25nm) / B:Liq (50%:50%, 30nm) / Yb (2nm) / Mg:Ag (10:1, 150nm).

[0095] Suzhou FS-100GA4 was used to test the brightness, luminous efficiency, and EQE (external quantum efficiency) of the organic electroluminescent elements of Examples 1 to 4 and Comparative Examples 1 to 3, and FS-MP96 was used to test the life LT98 (the time taken for the initial brightness to decay to 3920 nits from 4000 nits) of each organic electroluminescent element. All measurements were completed in the atmosphere at room temperature. The organic electroluminescent element was 10 mA / cm 2 The specific performance data of ETM (quinoxaline-triazine compound, bistriazine compound and their mass ratio) under current density, operating voltage (V), current efficiency (CE), power efficiency (PE), external quantum efficiency (EQE) and color coordinates (CIEx, CIEy) are shown in Table 1.

[0096] Table 1

[0097]

[0098]

[0099] Compared with Comparative Examples 1 and 2, the driving voltage of the organic electroluminescent elements of Examples 1 to 4 is significantly reduced and the efficiency is significantly improved. Compared with Comparative Example 3, the life of the organic electroluminescent elements of Examples 1 to 4 is significantly improved.

[0100] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0101] The quinoxaline-triazine compound with chemical formula A1 or A2 helps to increase the life of the organic electroluminescent device, and the bistriazine compound with chemical formula B1 or chemical formula B helps to reduce the driving voltage of the organic electroluminescent device and improve the device efficiency. The present application uses the above-mentioned quinoxaline-triazine compound and the bistriazine compound in combination, comprehensively utilizes the advantages of the two, and alleviates the disadvantages of the two to the organic electroluminescent device, thereby obtaining an organic electroluminescent device with high efficiency, long life and low driving voltage.

[0102] 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.

Claims

1. An organic electroluminescent element, comprising an anode, a cathode, a hole injection layer, a hole transport layer, a light emitting layer and an electron transport layer, characterized in that: The electron transport layer includes a quinoxaline-triazine compound and a bistriazine compound, wherein the quinoxaline-triazine compound is any one of the compounds represented by chemical formula A1 or A2, and the bistriazine compound has a chemical formula B:

2. The organic electroluminescent element according to claim 1, characterized in that: The mass ratio of the quinoxaline-triazine compound to the bistriazine compound is 3-7:7-3.

3. The organic electroluminescent element according to claim 1, characterized in that: The hole injection layer comprises any one or more arylamine compounds and any one or more radialene derivatives doped therein, The arylamine compound has the general formula I: wherein Ar1, Ar2, Ar3, and Ar4 are each independently a substituted or unsubstituted C6-C 30 Aryl, substituted or unsubstituted C5-C 30 Heteroaryl, the substituents on both Ar1 and Ar2, and both Ar3 and Ar4 may be combined to form a ring via a single bond, a substituted or unsubstituted methylene, an oxygen atom or a sulfur atom; The radialene derivative has the general formula II: Wherein Ar5 is a C6-C 18 The aromatic group.

4. The organic electroluminescent element according to claim 3, characterized in that: The electron withdrawing group is fluorine or cyano.

5. The organic electroluminescent element according to claim 3, characterized in that: In the general formula I, Ar1, Ar2, Ar3, and Ar4 are each independently selected from any one of substituted or unsubstituted phenyl, biphenyl, naphthyl, fluorenyl, and carbazole.

6. The organic electroluminescent element according to any one of claims 3 to 5, characterized in that: In the general formula II, Ar5 is selected from a phenyl or biphenyl group containing at least one cyano group or F atom substituted.

7. The organic electroluminescent element according to any one of claims 3 to 5, characterized in that: Among the plurality of aromatic amine compounds and the radialene derivative, the doping mass ratio of the radialene derivative is 2% to 20%.

8. The organic electroluminescent element according to any one of claims 3 to 5, characterized in that: The hole transport layer includes a first hole transport layer and a second hole transport layer which are sequentially stacked away from the hole injection layer, and the first hole transport layer includes any one or more of the arylamine compounds.

9. The organic electroluminescent element according to any one of claims 1 to 5, characterized in that: The light-emitting layer is composed of at least a host matrix and a guest dopant mixed together.

10. The organic electroluminescent element according to claim 9, characterized in that: The main matrix is ​​an anthracene compound represented by the general formula BH: wherein R1 and R2 are the same or different from each other and are each independently hydrogen, substituted or unsubstituted C1-C6 alkyl, alkoxy, C6-C 30 an aryl or heteroaryl group; Ar6 and Ar7 are each independently selected from C6-C 30 an aryl or heteroaryl group; a, b, c are each an integer of 1 to 4, and when a, b, c are each an integer of 2 or more, two or more structures in the brackets are the same as or different from each other.

11. The organic electroluminescent element according to claim 9, characterized in that: The guest dopant of the light-emitting layer is a fluorescent dye represented by the general formula BD, Among them, R3 to R 10 are each independently a hydrogen atom, a halogen atom, a substituted or unsubstituted C1-C4 alkyl group, a substituted or unsubstituted C3-C 10 cycloalkyl, substituted or unsubstituted silyl, cyano, or substituted or unsubstituted C6-C 30 The aromatic group; Ar8 to Ar 11 Each independently is substituted or unsubstituted C6-C 30 aryl, or substituted or unsubstituted C5-C 30 The heteroaryl group.

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