An organic electroluminescent element

Abstract

The present invention provides an organic electroluminescent element. The organic electroluminescent element comprises a hole injection layer, a hole transport layer, a light-emitting layer and an electron transport layer stacked in sequence, wherein the main body of the light-emitting layer is composed of compound A and compound B; the electron transport layer comprises compound C; the two main body materials in the light-emitting layer of the organic electroluminescent element have the same fragment, which increases the compatibility between the two materials, is beneficial to improving the film quality, and is more conducive to the full combination of electrons and holes, and is combined with compound C as an electron transport material to improve the luminous efficiency of the organic electroluminescent element.

Description

Technical Field

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

[0002] Organic electroluminescent elements have been used in smart phones, tablet computers, and automotive fields due to their characteristics of lightness, wide viewing angle, high contrast, low power consumption, high response speed, full-color display, and flexibility, and are expanding to large-size application areas such as televisions.

[0003] Organic electroluminescent elements usually include a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, a hole blocking layer, an electron transport layer, an electron injection layer and other film layers. Holes and electrons are injected from the anode and cathode respectively, enter the light-emitting layer through the transport layer, and recombine with each other to emit light. The efficiency of the element depends on the recombination probability of holes and electrons, so regulating the balance of carriers at both ends is the key. The main means of regulation are: improving the injection and transport properties of holes and electrons, thereby increasing the probability of hole-electron recombination; improving the blocking properties of holes and electrons, thereby confining the generated excitons in the light-emitting layer to obtain high luminous efficiency; or co-evaporating electron-transporting materials and hole-transporting materials to form dual-host materials, so that electrons and holes can be transmitted at the same time, so that the two are balanced, reducing exciton quenching, and thus improving luminous efficiency.

[0004] The selection of dual-host materials requires many factors to be considered. It is not a simple mixture of two materials. Not only the energy level matching between the materials needs to be considered, but also the balance of electron and hole transport capabilities and the stability of the materials need to be considered. Among them, the film quality of the light-emitting layer is the key to determining the efficiency of the device. Summary of the invention

[0005] The main purpose of the present invention is to provide an organic electroluminescent element to solve the problems of poor compatibility and poor film quality in the organic electroluminescent element using dual host materials in the prior art.

[0006] 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 a hole injection layer, a hole transport layer, a light-emitting layer and an electron transport layer stacked in sequence, the main body of the light-emitting layer is composed of compound A and compound B,

[0007]

[0008] The electron transport layer comprises compound C:

[0009]

[0010] Furthermore, the hole injection layer comprises any one or more arylamine compounds and any one or more radialene derivatives doped therein.

[0011] The arylamine compounds have the general formula I: wherein Ar1 to Ar4 are each independently a substituted or unsubstituted C6-C 30 Aryl, substituted or unsubstituted C5-C 30 Heteroaryl, the substituents on Ar1 and Ar2, 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, and n is any integer from 0 to 4;

[0012] The radialene derivatives have the general formula II: Wherein Ar5 is a C6-C 18 The electron withdrawing group is preferably fluorine or cyano.

[0013] Furthermore, in the above general formula I, Ar1 to Ar4 are each independently selected from any one of substituted or unsubstituted phenyl, biphenyl, naphthyl, fluorenyl or carbazole.

[0014] Furthermore, in the above general formula II, Ar5 is selected from a phenyl or biphenyl group containing at least one cyano group or F atom substituted.

[0015] Furthermore, in the above-mentioned arylamine compound and the radialene derivative, the doping mass ratio of the radialene derivative is 2% to 20%.

[0016] Furthermore, the hole transport layer comprises 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 comprises any one or more aromatic amine compounds.

[0017] Furthermore, the second hole transport layer comprises any one or more triarylamine compounds represented by general formula III:

[0018]

[0019] wherein Ar6, Ar7 and Ar8 are each independently a substituted or unsubstituted C6-C 30 Aryl, substituted or unsubstituted C5-C 30 Any of the heteroaryl groups.

[0020] Furthermore, in the above general formula III, Ar6, Ar7 and Ar8 are each independently selected from any one of biphenyl, fluorenyl, dibenzofuranyl, phenyl-substituted naphthyl, phenyl-substituted dibenzofuranyl or phenyl-substituted carbazolyl.

[0021] Furthermore, the guest of the above-mentioned light-emitting layer is any one or more phosphorescent red dyes represented by general formula IV:

[0022]

[0023] Wherein, R1, R2, R3, and R4 are each independently selected from hydrogen, substituted or unsubstituted C1-C10 alkyl, substituted or unsubstituted C6-C30 aryl, or substituted or unsubstituted C5-C30 heteroaryl; m and n are integers from 0 to 4.

[0024] Furthermore, in the above general formula IV, R1, R2, R3, and R4 are each independently selected from any one of methyl, ethyl, isopropyl, isobutyl or 3-methylpentyl, m is preferably 1 or 2, and n is preferably 1 or 2.

[0025] By applying the technical solution of the present invention, the two main materials of the light-emitting layer of the organic electroluminescent element have the same fragments, which increases the compatibility between the two materials, is beneficial to improving the quality of the film layer, and is more conducive to the full combination of electrons and holes. When compound C is used as an electron transport material, the luminous efficiency of the organic electroluminescent element is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] 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:

[0027] Figure 1 A schematic structural diagram of an OLED element provided according to an embodiment of the present invention is shown;

[0028] Figure 2 The current density-external quantum efficiency test graphs of the devices prepared in the device embodiments of the present invention and the comparative examples are shown.

[0029] The above drawings include the following reference numerals:

[0030] 1. Anode layer; 2. Hole injection layer; 3. First hole transport layer; 4. Second hole transport layer; 5. Light-emitting layer; 6. Electron transport layer; 7. Electron injection layer; 8. Cathode layer. DETAILED DESCRIPTION

[0031] 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.

[0032] As analyzed in the background technology of this application, in the prior art, although it is theoretically possible to combine fragments with electron activity and fragments with hole activity to form a bipolar host material, thereby being able to simultaneously transmit electrons and holes, balance the two, reduce exciton quenching, and thus improve luminous efficiency. However, in practice, due to the influence of the application environment, etc., not all bipolar host materials with the above characteristics can achieve the effect of improving luminous efficiency. The improvement in luminous efficiency is affected by the compatibility of the materials. Once the compatibility of the materials is insufficient, it directly affects the quality of the film layer. Based on this, in order to improve the compatibility of the materials and the quality of the film layer, the present application provides an organic electroluminescent element, which includes a hole injection layer, a hole transport layer, a light-emitting layer and an electron transport layer stacked in sequence, and the main body of the light-emitting layer includes compound A and compound B,

[0033]

[0034] The electron transport layer comprises compound C:

[0035]

[0036] The two main materials of the light-emitting layer of the organic electroluminescent element of the present application have the same fragments, which increases the compatibility between the two materials, is beneficial to improving the quality of the film layer, and is more conducive to the full combination of electrons and holes. When combined with compound C as an electron transport material, the luminous efficiency of the organic electroluminescent element is improved.

[0037] 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.

[0038] The arylamine compounds have the general formula I: wherein Ar1 to Ar4 are each independently a substituted or unsubstituted C6-C 30 Aryl, substituted or unsubstituted C5-C 30 Heteroaryl, the substituents on Ar1 and Ar2, 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, and n is any integer from 0 to 4;

[0039] The radialene derivatives have the general formula II: Wherein Ar5 is a C6-C 18 The electron withdrawing group is preferably fluorine or cyano.

[0040] 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.

[0041] In a preferred embodiment, in the above general formula I, Ar1 to Ar4 are each independently selected from any one of substituted or unsubstituted phenyl, biphenyl, naphthyl, fluorenyl, phenyl or carbazole. Further, it is preferred that the above arylamine compound is selected from any one or more of the following compounds:

[0042]

[0043]

[0044] Preferably, in the above general formula II, Ar5 is selected from a phenyl or biphenyl group containing at least one cyano group or F atom substituted. Further, the above radialene derivative can be selected from any one or more of the following compounds:

[0045]

[0046]

[0047] 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 doping mass ratio of the arylamine compound and the radium derivative is 2% to 20%, and it is further preferred that the doping mass ratio of the radium derivative is 2% to 8%.

[0048] In one embodiment of the present application, the hole transport layer comprises a first hole transport layer and a second hole transport layer stacked sequentially away from the hole injection layer, and the first hole transport layer comprises an arylamine compound. Both the first hole transport layer and the hole injection layer comprise an arylamine compound, 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.

[0049] In one embodiment, the second hole transport layer comprises any one or more triarylamine compounds represented by general formula III:

[0050]

[0051] wherein Ar6, Ar7 and Ar8 are each independently a substituted or unsubstituted C6-C 30 Aryl, substituted or unsubstituted C5-C 30The triarylamine compound enables the second hole transport layer to assist in further hole transport on the one hand, and on the other hand, to confine electrons in the light-emitting layer to improve the light-emitting efficiency.

[0052] Further, in the above general formula III, Ar6, Ar7 and Ar8 are each independently selected from any one of biphenyl, fluorenyl, dibenzofuranyl, phenyl-substituted naphthyl, phenyl-substituted dibenzofuranyl or phenyl-substituted carbazole. Preferably, the above triarylamine compound can be selected from any one or more of the following compounds:

[0053]

[0054]

[0055] In order to further improve the luminous efficiency and stability, it is preferred that the guest of the above-mentioned luminescent layer is any one or more phosphorescent red dyes represented by general formula IV:

[0056]

[0057] wherein R1, R2, R3, and R4 are each independently selected from hydrogen, substituted or unsubstituted C1-C10 alkyl, substituted or unsubstituted C6-C30 aryl, or substituted or unsubstituted C5-C30 heteroaryl;

[0058] m, n are integers of 0 to 4.

[0059] The phosphorescent red dye having the above structure cooperates with the host material in the light-emitting layer to achieve a better electron-hole recombination effect.

[0060] Furthermore, in the above general formula IV, R1, R2, R3, and R4 are each independently selected from any one of methyl, ethyl, isopropyl, isobutyl, or 3-methylpentyl, m is preferably 1 or 2, and n is preferably 1 or 2. Preferably, the above phosphorescent red dye is selected from any one or more of the following compounds:

[0061]

[0062] The beneficial effects of the present application will be further illustrated below in combination with embodiments and comparative examples.

[0063] Synthesis Example

[0064] 1. Synthesis of Compound A

[0065]

[0066] In a 500mL three-necked flask, add 4-bromo-o-phenylenediamine (20g, 0.106mol), acenaphthenequinone (19.31g, 0.106mol) and toluene (350ml), and heat under reflux for 6 hours. After the reaction is completed, cool to room temperature, filter, and obtain 32.4g of crude intermediate M1, which is a brown solid powder with a yield of 91% and a purity of 99.02%.

[0067]

[0068] The air in the clean 1000ml three-necked flask was replaced with nitrogen to ensure oxygen-free conditions for 10 minutes, and then toluene (340ml), ethanol (90ml), water (60ml), M1 (20g, 60mmol), 4-dibenzofuran boronic acid (15.26g, 72mmol), sodium carbonate (12.72g, 120mmol), tris(dibenzylideneacetone)palladium (0.26g), 2-dicyclohexylphosphine-2,4,6-triisopropylbiphenyl (0.28g) were added in sequence, and heated under reflux for 4 hours under nitrogen protection. After the reaction was completed, it was cooled to room temperature, and the filter cake was obtained by vacuum filtration. The filter cake was heated and dissolved with toluene and then passed through a short silica gel column while hot. The filtrate was vacuum evaporated to remove the solvent, and recrystallized in toluene to obtain 18g of compound A, which was an off-white solid powder with a yield of 71% and a purity of 99.90%. Compound A was purified by vacuum sublimation twice with a purity of 99.93%.

[0069] The structural characterization results of compound A are as follows:

[0070] 1 H NMR (400MHz, DMSO) δ8.82(d,J=1.3Hz,1H),8.52(dd,J=6.8,4.8Hz,2H),8.47–8.40(m,2H),8.37(d,J=8.2Hz,2H),8.28(dd ,J=10.3,3.8Hz,2H),8.06–7.96(m,3H),7.87(d,J=8.2Hz,1H),7.61(ddd,J=12.6,9.7,4.5Hz,2H),7.49(t,J=7.5Hz,1H).

[0071] 2. Synthesis of Compound B

[0072]

[0073] In a 2000ml three-necked flask, add m-bromoiodobenzene (88.7g, 0.31mol), dibenzofuran-4-boric acid (70g, 0.33mol), potassium carbonate (86.7g, 0.62mol), tetrakis-(triphenylphosphine) palladium (1.8g), toluene (480ml), ethanol (70ml) and water (240ml), and heat under reflux for 6 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 evaporation of the filtrate to remove the solvent to obtain 100g of oily substance, which is recrystallized with n-hexane to obtain 60g of intermediate M2, which is an off-white solid powder with a yield of 60% and a purity of 98.4%.

[0074] In a 2000ml three-necked flask, add intermediate M2 (50g, 0.15mol), 4-chlorophenylboronic acid (25.4g, 0.16mol), potassium carbonate (41.5g, 0.3mol), bis(triphenylphosphine)palladium dichloride (0.55g), toluene (500ml), ethanol (125ml) and water (250ml), and heat under reflux for 6 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 evaporation of the filtrate to remove the solvent to obtain 55g of oily substance, which is recrystallized with n-hexane to obtain 43g of intermediate M3, which is an off-white solid powder with a yield of 80% and a purity of 97.7%.

[0075]

[0076] Add 300ml toluene and sodium tert-butoxide (12g, 175mmol) to a 500ml three-necked flask, reflux for half an hour under nitrogen; then cool to 80°C, add intermediate M3 (30g, 84.5mmol), di(4-biphenyl)amine (27.2g, 84.5mmol), tris[dibenzylideneacetone]dipalladium (0.5g) / tri-tert-butylphosphine (1.5g) in sequence, stir for 15min, turn on the heating, and heat to reflux for 4 hours. After the reaction is completed, turn off the heating, stir to about 60°C, wash with water twice, and separate the liquids; take the organic layer and filter it with silica gel pad, and vacuum evaporation of the filtrate to remove the solvent to obtain 65g of oily substance, which is recrystallized three times with toluene / ethanol to obtain 37.5g of compound B, which is an off-white solid powder with a yield of 69.4% and a purity of 99.1%. Compound B is purified by vacuum sublimation twice with a purity of 99.84%.

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

[0078] 1H NMR (400MHz, DMSO) δ8.22–8.07(m,3H),7.83(t,J=10.0Hz,1H),7.80–7.67(m,5H),7.66–7.55(m,9 H),7.55–7.45(m,2H),7.41(t,J=7.6Hz,5H),7.30(ddd,J=6.7,4.5,1.1Hz,2H),7.22–7.09(m,6H).

[0079] 3. Synthesis of Compound C

[0080]

[0081] In a 500mL three-necked flask, add 4-bromo-o-phenylenediamine (20g, 0.106mol), 2,3-butanedione (9.66g, 0.112mol) and toluene (200ml), and heat to reflux for 3 hours. After the reaction is completed, cool to room temperature, filter with silica gel pad, and use vacuum to evaporate the solvent in the filtrate to obtain a crude product. The crude product is dissolved and decolorized with n-hexane and recrystallized to obtain 18.0g of intermediate M4, which is an off-white solid powder with a yield of 71%. The purity is 99.95%.

[0082] In a three-necked flask, add intermediate M4 (10g, 0.042mol), 2,4-diphenyl-6-[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl]-1,3,5-triazine (18.36g, 0.042mol), potassium carbonate (11.65g, 0.084mol), tetrakis-(triphenylphosphine)palladium (0.49g), toluene (150ml), ethanol (45ml) and water (30ml), and heat under reflux for 8 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 solvent in the filtrate to obtain a crude product, which is dissolved in toluene for decolorization and recrystallization to obtain 13.3g of compound C, which is a white solid powder with a yield of 68% and a purity of 99.93%. Compound C was purified twice by vacuum sublimation with a purity of 99.96%.

[0083] The structural characterization results of compound C are as follows:

[0084] 1H NMR (400MHz, CDCl3) δ8.89 (d, J = 8Hz, 2H), 8.80 (d, J = 7.2Hz, 4H), 8.32 (s, 1H), 8. 06(dd,J=21.4,8.6Hz,2H),7.95(d,J=8Hz,2H),7.65-7.58(m,6H),2.77(s,6H).

[0085] The physicochemical properties of compound A, compound B and compound C were characterized. The absorption wavelength of the material was measured using a Shimadzu UV-2600 ultraviolet spectrophotometer. The solvent was THF and the material concentration was about 10 ppm. g =1240 / UV onset ; Vertex.C.EIS electrochemical workstation was used, the working electrode was a glassy carbon electrode, the reference electrode was a saturated calomel electrode-saturated potassium chloride solution, the counter electrode was a platinum wire electrode, and the solvent was 50% dichloromethane + 50% acetonitrile (the material concentration was about 5×10 -4 mol / L), the electrolyte is 0.1M tetrabutylammonium hexafluorophosphate, the standard is ferrocene, and the measurement starts after nitrogen is passed for 10 minutes at room temperature. The scanning condition is rate = 0.1V / s, and the redox potential of the material is measured and finally converted into LUMO and HOMO energy poles. The characterization results are shown in Table 1.

[0086] Table 1

[0087]

[0088] 3. Preparation of organic electroluminescent elements

[0089] The actual effect of the organic electroluminescent device prepared by the material combination adopted in the present invention is described in detail below through specific examples and comparative examples.

[0090] Device Example 1

[0091] Reference Figure 1 The structure shown in the figure is used to manufacture the OLED element using a Sunic sp1710 evaporation machine. The specific steps are as follows: a glass substrate (Corning glass 40mm*40mm*0.7mm) coated with ITO (indium tin oxide, as the anode layer 1) 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; HT1 and HD mixed (HD doping mass ratio is 4%) are vacuum (about 10 -7Torr) thermal deposition of 20nm thickness to form a hole injection layer 2; then vacuum depositing 90nm thick HT1 on the hole injection layer as the first hole transport layer 3; then vacuum depositing 70nm thick HT2 to form a second hole transport layer 4; then vacuum depositing 30nm of compound A and compound B (mass fraction 31%:65%) doped with 4% phosphorescent green guest GD1; then vacuum depositing 50% LiQ (8-hydroxyquinoline lithium) doped ET1 to form an electron transport layer 6 with a thickness of 30nm; finally, depositing 2nm thick metal ytterbium (Yb, as an electron injection layer 7) and a magnesium-silver alloy doped with a ratio of 10:1 in sequence to form a cathode layer 8; finally, the component 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 desiccant.

[0092] In the above manufacturing steps, the deposition rates of the organic material, metal ytterbium, and metal Mg were maintained at 0.1 nm / s, 0.05 nm / s, and 0.2 nm / s, respectively.

[0093]

[0094] The structure of the element is represented as: ITO (135nm) / HT1:4% HD (20nm) / HT1 (90nm) / HT2 (70nm) / Compound A: Compound B: RD (31%:65%:4%, 30nm) / Compound C: LiQ (5:5, 30nm) / Yb (2nm) / Mg:Ag (10:1, 150nm).

[0095] Device Comparison Example 1

[0096] The experiment was conducted in the same manner as in Example 1, except that RH1 and Compound B were used as dual hosts (mass fraction 31%:65%).

[0097] The structure of the element is represented as: ITO (135nm) / HT1: 4% HD (20nm) / HT1 (90nm) / HT2 (70nm) / RH1: Compound B: RD (31%: 65%: 4%, 30nm) / Compound C: LiQ (5: 5, 30nm) / Yb (2nm) / Mg: Ag (10: 1, 150nm).

[0098] Device Comparison Example 2

[0099] The experiment was conducted in the same manner as in Example 1, except that RH2 and Compound B were used as dual hosts (mass fraction 31%:65%).

[0100] The structure of the element is represented as: ITO (135nm) / HT1:4% HD (20nm) / HT1 (90nm) / HT2 (70nm) / RH2: Compound B: GD1 (1%:65%:4%, 30nm) / Compound C: LiQ (5:5, 30nm) / Yb (2nm) / Mg: Ag (10:1, 150nm).

[0101] Device Comparison Example 3

[0102] The experiment was conducted in the same manner as in Example 1, except that Compound C and Compound B were used as dual hosts (mass fraction 31%:65%).

[0103] The structure of the element is represented as: ITO (135nm) / HT1:4% HD (20nm) / HT1 (90nm) / HT2 (70nm) / RH2: Compound B: GD1 (1%:65%:4%, 30nm) / Compound C: LiQ (5:5, 30nm) / Yb (2nm) / Mg: Ag (10:1, 150nm).

[0104] The brightness, luminous efficiency, and EQE (external quantum efficiency) of the components were tested by Suzhou Fushida FS-100GA4. All measurements were completed in the room temperature atmosphere. 2 The specific performance data of the working voltage (V), current efficiency (CE), external quantum efficiency (EQE) and color coordinates (CIEx, CIEy) under current density are shown in Table 2. The trend of external quantum efficiency changing with current density is shown in Figure 2 .

[0105] Table 2

[0106]

[0107] It can be seen from the table that the above embodiments of the present invention achieve the following technical effects:

[0108] The two main materials RH1 and compound B in device comparison example 1 are combined, and the two have neither the same fragment nor the same fragment as the materials of the adjacent electron transport layer and the second hole transport layer. The film interface barrier is large, resulting in low device efficiency; the two main materials RH2 and compound B in device comparison example 2 are combined, wherein RH2 has the same fragment as the electron transport layer material compound C, so the film interface is optimized and the device efficiency is improved; the two main materials compound C and compound B in device comparison example 3 are combined, wherein compound C is exactly the same as the electron transport layer material, and relative to device comparison example 2, the efficiency of device comparison example 3 is further improved; compared with device comparison example 3, device embodiment 1 uses a combination of main materials compound A and compound B, both of which have a common dibenzofuran fragment, thereby optimizing the film quality of the light-emitting layer, which is more conducive to the full recombination of electrons and holes, so the device efficiency is significantly improved, which further illustrates that for improving device efficiency, the improvement of the film layer within the light-emitting layer is more obvious than the improvement of the interface film layer.

[0109] 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 a hole injection layer, a hole transport layer, a light-emitting layer and an electron transport layer stacked in sequence, characterized in that: The main body of the light-emitting layer is composed of compound A and compound B: The electron transport layer comprises compound C:

2. 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 to 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, and n is any integer from 0 to 4; The radialene derivative has the general formula II: Wherein Ar5 is a C6-C 18 The aromatic group.

3. The organic electroluminescent element according to claim 2, characterized in that: In the general formula II, the electron withdrawing group is fluorine or cyano.

4. The organic electroluminescent element according to claim 2, characterized in that: In the general formula I, Ar1 to Ar4 are each independently selected from any one of a substituted or unsubstituted phenyl group, a biphenyl group, a naphthyl group, a fluorenyl group or a carbazole group.

5. The organic electroluminescent element according to claim 2, 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.

6. The organic electroluminescent element according to any one of claims 2 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%.

7. The organic electroluminescent element according to any one of claims 2 to 4, 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.

8. The organic electroluminescent element according to claim 7, characterized in that: The second hole transport layer includes any one or more triarylamine compounds represented by general formula III: wherein Ar6, Ar7 and Ar8 are each independently a substituted or unsubstituted C6-C 30 Aryl, substituted or unsubstituted C5-C 30 Any of the heteroaryl groups.

9. The organic electroluminescent element according to claim 6, characterized in that: In the general formula III, Ar6, Ar7 and Ar8 are each independently selected from any one of biphenyl, fluorenyl, dibenzofuranyl, phenyl-substituted naphthyl, phenyl-substituted dibenzofuranyl or phenyl-substituted carbazolyl.

10. The organic electroluminescent element according to claim 1, characterized in that: The guest of the light-emitting layer is any one or more phosphorescent red dyes represented by general formula IV: wherein R1, R2, R3, and R4 are each independently selected from hydrogen, substituted or unsubstituted C1-C10 alkyl, substituted or unsubstituted C6-C30 aryl, or substituted or unsubstituted C5-C30 heteroaryl; m, n are integers of 0 to 4.

11. The organic electroluminescent element according to claim 10, characterized in that: In the general formula IV, the R1, the R2, the R3, and the R4 are each independently selected from any one of methyl, ethyl, isopropyl, isobutyl, and 3-methylpentyl.

12. The organic electroluminescent element according to claim 11, characterized in that: In the general formula IV, m is 1 or 2.

13. The organic electroluminescent element according to claim 11 or 12, characterized in that: In the general formula IV, n is 1 or 2.

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