A red light organic electroluminescence device and an electronic device comprising the same

Abstract

This invention belongs to the technical field of organic electroluminescent devices, and provides a red organic electroluminescent device and an electronic device comprising the same. The red organic electroluminescent device includes a first electrode, a second electrode, and an organic layer formed between the first and second electrodes. The organic layer includes at least a hole transport layer, a first light-emitting auxiliary layer, a second light-emitting auxiliary layer, and a light-emitting layer. The HOMO energy level of the hole transport layer is higher than that of the first light-emitting auxiliary layer, the HOMO energy level of the first light-emitting auxiliary layer is higher than that of the second light-emitting auxiliary layer, and the HOMO energy level of the second light-emitting auxiliary layer is higher than that of the light-emitting layer. The device disclosed in this invention has low driving voltage, long lifespan, and excellent luminous efficiency, making it suitable for widespread application.

Description

Technical Field

[0001] This invention belongs to the technical field of organic electroluminescent devices, specifically relating to a red organic electroluminescent device and an electronic device containing the same. Background Technology

[0002] Organic light emission refers to the phenomenon of converting electrical energy into light energy using organic materials. Organic electroluminescent devices based on this phenomenon typically include an anode, a cathode, and an organic layer disposed between the anode and cathode. To improve the luminous efficiency and stability of the organic electroluminescent device, the organic layer is usually configured as a multilayer structure formed from various different organic materials. For example, the organic layer may include multiple sublayers such as a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, and an electron injection layer. Typically, electrons transfer from the electron transport layer to the light-emitting layer, and holes transfer from the hole transport layer to the light-emitting layer, to generate excitons through recombination.

[0003] However, materials used for hole transport layers typically have low HOMO values ​​and low T1 values. This causes excitons generated in the emissive layer to be transferred to the hole transport layer, leading to charge imbalance and luminescence at the hole transport layer interface. To address these luminescence issues in the hole transport layer, previous research has proposed forming multiple hole transport layers. While this method can reduce the device's driving voltage, the use of highly conductive hole-transporting materials can easily lead to excessive charge injection, thus shortening the device's lifespan. Therefore, current research focuses on organic electronic devices that form an auxiliary luminescent layer between the hole transport layer and the emissive layer. Obtaining devices with low driving voltage, long lifespan, and excellent luminous efficiency is a key focus for future research. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide an organic electroluminescent red light device and an electronic device comprising the same, wherein the organic electroluminescent device has low driving voltage, long service life and excellent luminous efficiency.

[0005] To achieve this objective, the present invention adopts the following technical solution:

[0006] On one hand, the present invention provides a red organic electroluminescent device, the red organic electroluminescent device comprising a first electrode, a second electrode, and an organic layer formed between the first electrode and the second electrode; wherein, the organic layer comprises at least a hole transport layer, a first light-emitting auxiliary layer, a second light-emitting auxiliary layer, and a light-emitting layer; the hole transport layer is formed between the first electrode and the light-emitting layer, the first light-emitting auxiliary layer and the second light-emitting auxiliary layer are located between the light-emitting layer and the hole transport layer, the first light-emitting auxiliary layer is adjacent to the hole transport layer, and the second light-emitting auxiliary layer is adjacent to the light-emitting layer; The HOMO energy level of the hole transport layer is higher than that of the first light-emitting auxiliary layer, the HOMO energy level of the first light-emitting auxiliary layer is higher than that of the second light-emitting auxiliary layer, and the HOMO energy level of the second light-emitting layer is higher than that of the aforementioned light-emitting layer. That is: HOMO energy levels: hole transport layer > first luminescent auxiliary layer > second luminescent auxiliary layer > luminescent layer; The material of the second light-emitting auxiliary layer has the structure shown in Formula I: ; R1 is independently selected from C1-C6 alkyl groups that are partially or fully substituted with deuterium or are unsubstituted. Ar1 is independently selected from one of the following structures that are partially or completely substituted with deuterium or are unsubstituted: , Indicates the linking site of a functional group.

[0007] In Formula I, any hydrogen atom can be independently replaced by deuterium.

[0008] Preferably, the HOMO energy level of the first light-emitting auxiliary layer is -5.40eV ≥ the HOMO energy level of the first light-emitting auxiliary layer ≥ -5.48eV; the HOMO energy level of the second light-emitting auxiliary layer is -5.55eV > the HOMO energy level of the second light-emitting auxiliary layer ≥ -5.60eV.

[0009] Preferably, R1 is independently selected from methyl, ethyl, propyl, isopropyl, tert-butyl, and methyl groups that are partially or wholly substituted with deuterium or are not substituted with deuterium.

[0010] Preferably, the material of the second light-emitting auxiliary layer has any one of the structures shown in Formula I-1 and Formula I-2: .

[0011] The second light-emitting auxiliary layer material compound represented by Formula I can be specifically illustrated by the following compounds, but is not limited to them: .

[0012] In this invention, the material of the second light-emitting auxiliary layer shown in Formula I can be produced by methods known to those skilled in the art.

[0013] Preferably, the compound of the second light-emitting auxiliary layer material shown in Formula I can be synthesized by the following reaction scheme: (1) Control the reaction at -78℃, add THF and raw material B (1.2 eq) into a three-necked flask, replace with nitrogen, stir for 10-30 min and then add n-butyllithium (1.2 eq) dropwise, react for 2 h, then dissolve raw material A in THF and add it into the three-necked flask, stir evenly and then raise to room temperature and react for 2-16 h; after confirming that the reaction is complete, add water and dichloromethane for extraction, separate the liquid and liquid, combine the organic phases and concentrate, and use a mixed solution of dichloromethane and petroleum ether (V:V=1:2-1:5) to purify the compound shown in intermediate 1 by column chromatography.

[0014] (2) At room temperature, a mixture of intermediate 1 (1.0 eq) and toluene (3.0-8.0 eq) and THF (3.0-8.0 eq) was added to the reaction flask until dissolved, and then methanesulfonic acid (3.0-8.0 eq) was added and the reaction continued for 5-60 min. After the reaction was completed, water and dichloromethane were added for extraction and separation. The organic phases were combined and concentrated. The compound shown in intermediate 2 was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V=1:3-1:8).

[0015] (3) Add intermediate 2 (1.0 eq), raw material C (1.0-1.3 eq), sodium tert-butoxide or potassium tert-butoxide (2.0-4.0 eq) and toluene to a three-necked flask. Under nitrogen protection, add tris(dibenzylideneacetone)dipalladium (0.01-0.03 eq) and tritert-butylphosphine (0.02-0.15 eq). Stir the reaction at 110-120℃ for 1-10 h. After the reaction is complete, add water and dichloromethane for extraction and separation. Combine and concentrate the organic phases. Purify the compound shown in intermediate 3 by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V=1:3-1:8).

[0016] (4) Add intermediate 3 (1.0-1.3 eq), raw material D (1.0 eq), sodium tert-butoxide or potassium tert-butoxide (2.0-4.0 eq) and toluene to a three-necked flask. Under nitrogen protection, add tris(dibenzylideneacetone)dipalladium (0.01-0.03 eq) and tritert-butylphosphine (0.02-0.15 eq). Stir the reaction at 100-120℃ for 1-15 h. After the reaction is complete, add water and dichloromethane for extraction and separation. Combine and concentrate the organic phases. Purify the compound shown in Formula I by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V=1:3-1:10).

[0017] Synthesis route of Formula I: ; Hal is independently selected from chlorine, bromine, and iodine.

[0018] In contrast to the complex raw materials that are not publicly available, the invention will employ the classic Buchwald–Hartwig coupling reaction, lithiation reaction and / or dehydration reaction to synthesize the materials and apply them to this invention.

[0019] The organic layer in the red organic electroluminescent device of the present invention further includes at least one of a hole injection layer, an electron blocking layer, a hole blocking layer, an electron transport layer, and an electron injection layer.

[0020] The red-light organic electroluminescent device of the present invention can be a top-emitting type, a bottom-emitting type, or a bidirectional-emitting type. The device described in the present invention can be used in organic light-emitting devices, organic solar cells, electronic paper, organic photoreceptors, or organic thin-film transistors.

[0021] The red organic electroluminescent device of the present invention includes a first electrode, a second electrode facing the first electrode, and an organic layer between the first electrode and the second electrode; the organic layer includes at least a light-emitting layer, a hole transport layer between the first electrode and the light-emitting layer, a first light-emitting auxiliary layer, and a second light-emitting auxiliary layer; it may also include a hole injection layer and an electron blocking layer, and the space between the light-emitting layer and the second electrode may contain a hole blocking layer, an electron transport layer, and an electron injection layer. The organic electroluminescent device disclosed in this invention is a red light device. The light-emitting layer is a red light host and a red light dopant. The material of the second light-emitting auxiliary layer is of formula I and the HOMO energy level relationship is: hole transport layer > first light-emitting auxiliary layer > second light-emitting auxiliary layer > light-emitting layer. There are no special restrictions on the materials of other layers in OLED devices.

[0022] In this invention, the light-emitting layer comprises a red light host material and a red light dopant material.

[0023] In this invention, the first electrode is the anode and the second electrode is the cathode.

[0024] As an anode material, a material with a high work function is preferred in order to facilitate the injection of holes into the organic layer. Specific examples of anode materials that can be used in this invention include metals such as vanadium, chromium, copper, zinc, and gold, or their alloys; metal oxides such as zinc oxide, indium oxide, indium tin oxide (ITO), and indium zinc oxide (IZO); combinations of metals and oxides such as ZnO:Al or SnO2:Sb; and conductive polymers such as polypyrrole and polyaniline.

[0025] In this invention, the hole injection layer is preferably a p-doped hole injection layer, which means a hole injection layer doped with a p-doped agent. A p-doped agent is a material that can impart p-type semiconductor characteristics. P-type semiconductor characteristics refer to the characteristics of injecting or transporting holes at the HOMO energy level, that is, the characteristics of a material with high hole conductivity.

[0026] Hole injection layer materials include metalloporphyrins, oligothiophenes, aryl amine derivatives, hexanitrile hexaazabenzophenanthrene organic compounds, quinacridone organic compounds, perylene organic compounds, anthraquinones, and conductive polymers such as polyaniline and polythiophene. P-doped P-dopers can be illustrated by the following compounds, but are not limited to them.

[0027]

[0028] A hole transport layer is formed between the first electrode and the light-emitting layer. The HOMO energy level of the hole transport layer is higher than that of the first light-emitting auxiliary layer. The hole transport layer can be selected from aryl amine derivatives, conductive polymers, and block copolymers that simultaneously contain conjugated and non-conjugated parts. Specifically, the hole transport layer material is selected from the following compounds, but is not limited to them.

[0029]

[0030] The first luminescent auxiliary layer is adjacent to the hole transport layer; the HOMO energy level satisfies the following relationship: -5.40 eV ≥ HOMO energy level of the first luminescent auxiliary layer ≥ -5.48 eV. The material of the first luminescent auxiliary layer includes, but is not limited to, the following compounds: The material of the first luminescent auxiliary layer includes, but is not limited to, the following compounds: .

[0031] The second light-emitting auxiliary layer is adjacent to the light-emitting layer; the HOMO energy level of the second light-emitting auxiliary layer is -5.55eV > HOMO energy level ≥ -5.65eV, and the material of the second light-emitting auxiliary layer is the compound shown in Formula I of this invention.

[0032] The luminescent layer comprises a red light host and red light dopant; the host material is a red light host material, which may be an aromatic fused-ring derivative or a heterocyclic compound. For example, aromatic fused-ring derivatives include anthracene derivatives, pyrene derivatives, naphthalene derivatives, pentane derivatives, phenanthrene compounds, or fluoranthene compounds, while heterocyclic compounds include carbazole derivatives, dibenzofuran derivatives, or pyrimidine derivatives.

[0033] The dopant material is a red-light dopant, including aromatic amine derivatives, styrylamine compounds, boron complexes, fluoranthene compounds, and metal complexes. Specifically, the red-light dopant material of this invention is selected from the following compounds, but is not limited to them: .

[0034] The electron transport region is a layer that can improve the problem of deteriorated light brightness caused by changes in the current characteristics of the device when the device is exposed to high temperatures during the panel manufacturing process, and it can control the charge flow characteristics.

[0035] Materials used as electron transport regions include, but are not limited to, derivatives of oxazoles, imidazoles, thiazoles, triazines, metal chelates, quinoline derivatives, oxaloline derivatives, diazanthracene derivatives, diphenanthroline derivatives, silicon-containing heterocyclic compounds, perfluorinated oligomers, fluorenones, anthraquinone dimethane, biphenylquinone, thiamethane dioxide, oxazoles, oxadiazoles, triazoles, imidazoles, perylenetetracarboxylic acid, fluorenemethane, anthrones, and their derivatives, metal complexes, and nitrogen-containing 5-membered ring derivatives.

[0036] Specifically, electron-injected layer materials include fluorenone, anthraquinone dimethane, biphenylquinone, thiamethane dioxide, oxazole, oxadiazole, triazole, imidazole, perylenetetracarboxylic acid, fluorenemethane, anthrone, and their derivatives, metal complexes, and nitrogen-containing 5-membered ring derivatives, but are not limited to these.

[0037] As the cathode material mentioned above, a material with a low work function is generally preferred in order to facilitate the injection of electrons into the organic layer. Specific examples of cathode materials include metals such as magnesium, calcium, sodium, potassium, titanium, indium, yttrium, lithium, gadolinium, aluminum, silver, tin, and lead, or their alloys: multilayered materials such as LiF / Al or LiO2 / Al, and Mg / Ag.

[0038] Organic light-emitting elements can be manufactured by sequentially stacking a first electrode, an organic layer, and a second electrode on a substrate, or by physical vapor deposition methods such as sputtering or electron beam evaporation.

[0039] An organic light-emitting element is formed by depositing a metal or a conductive metal oxide or alloy thereof onto a substrate. An organic layer comprising a hole injection layer, a hole transport layer, a light-emitting layer, and an electron transport layer is then formed on the first electrode. A material suitable for use as a second electrode is then deposited onto the organic layer. Alternatively, an organic light-emitting element can be fabricated by sequentially depositing a second electrode material, an organic layer, and a first electrode material onto the substrate.

[0040] Furthermore, regarding the compound represented by Formula I above, the organic layer can be formed not only by vacuum evaporation but also by solution coating when manufacturing organic light-emitting elements. Solution coating methods include, but are not limited to, spin coating, dip coating, blade coating, inkjet printing, screen printing, spray coating, and roller coating.

[0041] On the other hand, the present invention provides an electronic device comprising the red organic electroluminescent device as described above.

[0042] As can be seen from the above technical solution, the present invention has the following beneficial effects: The present invention uses the compound shown in Formula I as the second light-emitting auxiliary layer material, which, when paired with the first light-emitting auxiliary layer material, has a more suitable HOMO energy level, enabling more efficient exciton transfer. This results in the device having excellent performance, lower driving voltage, longer lifespan, and higher luminous efficiency. Attached Figure Description

[0043] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0044] Figure 1 The above is the proton NMR spectrum of compound 1 provided in Example 1 of this invention. Detailed Implementation

[0045] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0046] This invention discloses a red organic electroluminescent device and an electronic device comprising the same.

[0047] Additionally, it should be noted that the values ​​given in the following embodiments are as accurate as possible. However, those skilled in the art will understand that due to unavoidable measurement errors and experimental issues, each number should be understood as an approximation rather than an absolutely accurate value.

[0048] The features and performance of the present invention will be further described in detail below with reference to specific embodiments.

[0049] Example 1

[0050] The reaction was controlled at -78℃. THF and starting material B-1 (1.2 eq, CAS No.: 1233365-09-7) were added to a three-necked flask, nitrogen gas was introduced, and the mixture was stirred for 30 min. Then, n-butyllithium (1.2 eq) was added dropwise, and the reaction was allowed to proceed for 2 h. Next, starting material A-1 (1.0 eq, CAS No.: 66-99-9) was dissolved in THF and added to the three-necked flask. After stirring evenly, the mixture was heated to room temperature and reacted for 14 h. After the reaction was completed, water and dichloromethane were added for extraction and separation. The organic phases were combined and concentrated. Intermediate 1 (yield: 71.4%) was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V=1:2).

[0051] At room temperature, a mixture of intermediate 1 (1.0 eq) and toluene (6.0 eq) and THF (6.0 eq) was added to a reaction flask until dissolved, and then methanesulfonic acid (6.0 eq) was added and the reaction continued for 60 min. After the reaction was completed, water and dichloromethane were added for extraction and separation. The organic phases were combined and concentrated. Intermediate 2 was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V=1:4) (yield: 78.6%).

[0052] Intermediate 2 (1.0 eq), starting material C-1 (1.2 eq, CAS No.: 92-67-1), sodium tert-butoxide (2.0 eq), and toluene were added to a three-necked flask. Under nitrogen protection, tris(dibenzylacetone)dipalladium (0.01 eq) and tri-tert-butylphosphine (0.04 eq) were added, and the mixture was stirred at 110 °C for 2 h. After the reaction was completed, water and dichloromethane were added for extraction, and the liquid was separated. The organic phases were combined and concentrated. Intermediate 3 (yield: 79.7%) was obtained by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V=1:5).

[0053] Intermediate 3 (1.0 eq), starting material D-1 (1.0 eq, CAS No.: 382602-31-5), sodium tert-butoxide (4.0 eq), and toluene were added to a three-necked flask. Under nitrogen protection, tris(dibenzylacetone)dipalladium (0.03 eq) and tri-tert-butylphosphine (0.06 eq) were added, and the mixture was stirred at 120 °C for 12 h. After the reaction was completed, water and dichloromethane were added for extraction, and the liquid was separated. The organic phases were combined and concentrated. Compound 1 was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V=1:5) (yield: 84.6%).

[0054] The obtained compound 1 was analyzed, and the results are as follows: HPLC purity: >99.8%.

[0055] Mass spectrometry test: Waters XEVO TQD mass spectrometer with ESI source.

[0056] Test value MS(ESI, m / Z): [M+H] + =665.46.

[0057] Elemental analysis: The test values ​​are: C, 91.82; H, 6.02; N, 2.21.

[0058] Nuclear magnetic resonance hydrogen spectrum: as shown Figure 1 As shown in (Compound 1).

[0059] In addition, it should be noted that other compounds can be obtained by referring to the preparation methods of the examples listed above, so they will not be listed one by one here.

[0060] HOMO level test: Using an electrochemical analyzer with a scan rate of 0.1 V / sec, the cyclic voltage and current of the compound were measured. The HOMO energy level was obtained using the current-voltage graph. The test results are shown in Table 1 below.

[0061] The structural formulas of compounds a and j are as follows:

[0062] Table 1. HOMO levels of the first luminescent auxiliary material, the second luminescent auxiliary material, and the comparative compound.

[0063] Device Example 1: Fabrication of a Red Organic Light Emitting Device (1) Anode: ITO anode: The ITO (indium tin oxide)-Ag-ITO (indium tin oxide) glass substrate with a coating thickness of 150nm was cleaned twice in distilled water, ultrasonically washed for 30min, and then repeatedly cleaned twice in distilled water, ultrasonically washed for 10min. After washing, it was baked in a vacuum oven at 220℃ for 2 hours. After baking, it was cooled down before use. Using this substrate as the anode, the device process was carried out by vapor deposition machine, and other functional layers were sequentially vapor deposited on it.

[0064] (2) Hole injection layer (HIL): Hole injection layer materials HT-1 and P-dopant-1 are vacuum evaporated at a evaporation rate of 1 Å / s, and the evaporation rate ratio of HT-1 and P-dopant-1 is 97:3, with a thickness of 10 nm.

[0065] (3) Hole transport layer (HTL): 130 nm of HT-1 was vacuum-deposited on the hole injection layer at a deposition rate of 1.5 Å / s as the hole transport layer.

[0066] (4) First light-emitting auxiliary layer (Prime1): The first light-emitting auxiliary layer material Prime-1 is vacuum-deposited on the hole transport layer at a deposition rate of 0.5 Å / s, with a thickness of 80 nm.

[0067] (5) Second light-emitting auxiliary layer (Prime2): Compound 1 of the present invention is vacuum-deposited on the first light-emitting auxiliary layer at a deposition rate of 0.5 Å / s as the second light-emitting auxiliary layer material, with a thickness of 10 nm.

[0068] (6) Emitting layer (EML): At a evaporation rate of 1 Å / s, a host material (Host-1 and Host-2) and a dopant material (Dopant) with a thickness of 40 nm are vacuum-deposited on the emitting auxiliary layer as the emitting layer, and the evaporation rate ratio of the two host materials and the dopant material is 97:3, wherein the evaporation rate ratio of Host-1 and Host-2 is 50:50.

[0069] (7) Hole blocking layer (HB): HB-1 is vacuum-deposited on the light-emitting layer at a deposition rate of 0.5 Å / s as a hole blocking layer with a thickness of 5 nm.

[0070] (8) Electron transport layer (ETL): ET-1 and Liq with a thickness of 30 nm are vacuum-deposited on the hole blocking layer at a deposition rate of 1 Å / s, and the deposition rate ratio of ET-1 and Liq is 50:50.

[0071] (9) Electron injection layer (EIL): A Yb film layer with a thickness of 1 nm is vacuum-deposited on the electron transport layer at a deposition rate of 0.5 Å / s.

[0072] (10) Cathode: Magnesium and silver were vacuum deposited on the electron injection layer at a deposition rate of 1 Å / s for 13 nm. The deposition rate ratio of magnesium to silver was 1:9 to obtain the cathode.

[0073] (11) Optical extraction layer (CPL): CPL-1 with a thickness of 70 nm was vacuum-deposited on the cathode at a deposition rate of 1 Å / s as the optical extraction layer.

[0074] (12) Encapsulate the substrate after vapor deposition: First, use a coating equipment to coat the cleaned cover plate with UV adhesive. Then, move the coated cover plate to the pressing section, place the vapor-deposited substrate on the top of the cover plate, and finally bond the substrate and cover plate together under the action of the bonding equipment, while simultaneously completing the UV adhesive photocuring.

[0075] The material structure used is shown below: .

[0076] Device Examples 2-139 Referring to the method provided in Device Example 1 above, the corresponding compounds in Table 2 were selected to replace Compound 1, and the second light-emitting auxiliary layer was deposited by vapor deposition to prepare the corresponding organic electroluminescent devices, which are respectively referred to as Device Example 2 to Device Example 139.

[0077] Device Comparison Example 1 - Device Comparison Example 21: The only difference between the preparation methods of the organic electroluminescent devices in Comparative Examples 1-10 and those in Device Example 1 is that the organic electroluminescent devices use existing compounds a-j instead of the second light-emitting auxiliary layer material (compound 1) in Device Example 1 for vapor deposition; Comparative Examples 11-21 are organic electroluminescent devices without the first light-emitting auxiliary layer material, and only the second light-emitting auxiliary layer material is vapor-deposited. It should be noted that, under the condition of only one light-emitting auxiliary layer in the device comparative examples, the single-layer thickness is consistent with the thickness of the double-layer Prime (Prime 1 is 80 nm + Prime 2 is 10 nm, and the total thickness is 90 nm). The chemical structural formulas of compounds a-j are as follows: .

[0078] The driving voltage and luminous efficiency of the organic electroluminescent devices obtained in Device Examples 1 to 139 and Comparative Examples 1 to 21 were characterized at a brightness of 6000 nits, and at a current density of 50 mA / cm². 2 The lifespan of the tested devices was determined, and the test results are shown in Table 2 below: Table 2 Device Test Results

[0079] As can be seen from the results in Table 2 above, when the materials used in the organic electroluminescent device of the present invention are used as the second light-emitting auxiliary layer material in combination with the first light-emitting auxiliary layer material to prepare red organic electroluminescent devices (device examples 1-139), compared with device comparative examples 1-10, the driving voltage, luminous efficiency and lifespan are significantly improved.

[0080] The difference between Device Example 1 and Device Comparative Example 11 and Device Comparative Example 1-10 and Device Comparative Example 11-20 is that it contains a double-layer light-emitting auxiliary layer material and a single-layer light-emitting auxiliary layer material. The use of a double-layer light-emitting auxiliary layer reduces the potential barrier between functional layers, makes the encounter of electrons and holes more balanced, balances the exciton concentration, reduces exciton quenching, effectively improves the luminous efficiency of the device, and obtains a device with better performance.

[0081] As can be seen from Comparative Examples 1-9 and Comparative Example 10, the HOMO energy level of the first light-emitting auxiliary layer is higher than that of the second light-emitting auxiliary layer. The two energy levels are matched, and the device has better performance.

[0082] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A red organic electroluminescent device, characterized in that, The red-light organic electroluminescent device includes a first electrode, a second electrode, and an organic layer formed between the first electrode and the second electrode; wherein the organic layer includes at least a hole transport layer, a first light-emitting auxiliary layer, a second light-emitting auxiliary layer, and a light-emitting layer; the hole transport layer is formed between the first electrode and the light-emitting layer, the first light-emitting auxiliary layer and the second light-emitting auxiliary layer are located between the light-emitting layer and the hole transport layer, the first light-emitting auxiliary layer is adjacent to the hole transport layer, and the second light-emitting auxiliary layer is adjacent to the light-emitting layer; the HOMO energy level of the hole transport layer is higher than the HOMO energy level of the first light-emitting auxiliary layer, the HOMO energy level of the first light-emitting auxiliary layer is higher than the HOMO energy level of the second light-emitting auxiliary layer, and the HOMO energy level of the second light-emitting auxiliary layer is higher than the HOMO energy level of the light-emitting layer; The material of the second light-emitting auxiliary layer has the structure shown in Formula I: ； R1 is independently selected from C1-C6 alkyl groups that are partially or fully substituted with deuterium or are unsubstituted. Ar1 is independently selected from one of the following structures that are partially or completely substituted with deuterium or are unsubstituted: ， Indicates the linking site of a functional group.

2. The red organic electroluminescent device according to claim 1, characterized in that, The material of the second light-emitting auxiliary layer has any one of the structures shown in Formula I-1 and Formula I-2: ； In Formula I, any hydrogen atom can be independently replaced by deuterium.

3. The red organic electroluminescent device according to claim 1 or 2, characterized in that, R1 is independently selected from methyl, ethyl, propyl, isopropyl, tert-butyl, and methyl groups that are partially or wholly substituted with deuterium or are not substituted with deuterium.

4. The red organic electroluminescent device according to claim 1, characterized in that, The second light-emitting auxiliary layer material represented by Equation I has the specific structure shown in the following formula: 。 5. The red organic electroluminescent device according to claim 1, characterized in that, The organic layer further includes at least one of a hole injection layer, an electron blocking layer, a hole blocking layer, an electron transport layer, and an electron injection layer.

6. An electronic device, characterized in that, The electronic device includes the red organic electroluminescent device as described in claim 1.

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