An organic electroluminescent device

Abstract

A novel organic electroluminescent device is disclosed. This novel organic electroluminescent device comprises multiple light-emitting units, a second organic layer, and a specific connecting layer, and controls LUMO. 第一有机材料 - Work function 金属 ≤2.1eV can promote electron separation at the metal-organic interface, thereby suppressing carrier recombination at the interface; controlling HOMO 第二有机材料 -LUMO 第一有机材料 With a voltage ≥0.3V, by adjusting the doping concentration of the first organic material, hole injection is controlled, and carrier recombination in the light-emitting layer is balanced, thereby significantly improving the device's efficiency and lifetime while reducing power consumption. This novel tandem organic electroluminescent device exhibits superior device performance and broader application prospects.

Description

Technical Field

[0001] This invention relates to an organic electroluminescent device. More particularly, it relates to an organic electroluminescent device comprising a plurality of light-emitting units and a specific interconnecting layer. Background Technology

[0002] Organic electronic devices include, but are not limited to, the following types: organic light-emitting diodes (OLEDs), organic field-effect transistors (O-FETs), organic light-emitting transistors (OLETs), organic photovoltaic devices (OPVs), dye-sensitized solar cells (DSSCs), organic optical detectors, organic photosensors, organic field-effect devices (OFETs), light-emitting electrochemical cells (LECs), organic laser diodes, and organic plasma light-emitting devices.

[0003] Organic light-emitting diodes (OLEDs) consist of a cathode, an anode, and a stack of organic light-emitting materials between the cathode and anode. By applying a voltage across the cathode and anode, electrical energy is converted into light, offering advantages such as wide viewing angle, high contrast, and faster response time. In 1987, Tang and Van Slyke of Eastman Kodak reported an OLED comprising an arylamine hole transport layer and a tri-8-hydroxyquinoline-aluminum layer as the electron transport and light-emitting layers (Applied Physics Letters, 1987, 51(12): 913-915). When a voltage was applied across the device, green light was emitted. This invention laid the foundation for the development of modern organic light-emitting diodes (OLEDs). Because OLEDs are self-emissive solid-state thin-film devices, they offer enormous potential for display and lighting applications.

[0004] From a device structure perspective, OLEDs can be divided into conventional single-layer structures and tandem structures (also known as stacked structures). A conventional single-layer OLED contains only one light-emitting unit between the cathode and anode, while a tandem OLED consists of multiple stacked light-emitting units. In a tandem OLED, adjacent light-emitting units are connected by a charge-generating layer, the performance of which directly affects parameters such as voltage, lifetime, and efficiency. Typically, the charge-generating layer contains n-type and p-type materials to generate electrons and holes. Patent application US 2010 / 0288362 A1 discloses an internal connection structure for a stacked OLED device, which includes a p-type layer, an intermediate layer (IL), preferably such as CuPc, and an n-type layer. The IL, p-type layer, and n-type layer are in close contact. The patent application specifies that the interphase (IL) contains a p-type compound with a LUMO level greater than 3.0 eV, and the p-type layer contains a hole transport material with an aromatic amine structure and a p-type dopant (PD). The LUMO level of the PD is greater than 4.5 eV. The application specifically points out that the p-type compound in the IL and the p-type dopant in the p-type layer are different. Although the patent application states that adding the IL can improve device stability, its disclosed internal interconnect structure does not include a metal layer, and the materials in the IL and p-type layer are different. Furthermore, the patent application does not address the need to balance the energy level relationship between the IL and the p-type layer; however, the energy level relationship has a significant impact on device performance. A large energy level difference can easily cause interface problems, affecting carrier transport. Moreover, using too many different materials can increase device fabrication costs.

[0005] Patent application CN112687811A discloses an organic electroluminescent device that uses a specific interconnecting layer to connect two light-emitting units. This interconnecting layer includes a specific organic buffer layer and a metal layer. However, it argues that the buffer layer has a shallow LUMO level and weak hole injection capability, which can easily lead to insufficient device voltage and lifetime. Therefore, it requires the use of a deeper-energy organic material as the buffer layer and limits the LUMO level of the organic material to be greater than 4.9 eV. Furthermore, this patent application does not address the impact of the energy level relationship between the buffer layer and the metal layer on device performance. Therefore, although the disclosed tandem organic electroluminescent device with two light-emitting units containing a specific interconnecting layer shows significant improvements in lifetime and voltage compared to a device without an organic buffer layer, the improvement in external quantum efficiency is not significant. Thus, the overall performance of the device needs further improvement.

[0006] Tandem organic light-emitting diodes (OLEDs), due to their thicker structure, can improve production line yield and require lower current densities than conventional single-layer OLEDs, thus extending lifespan. Furthermore, they can significantly increase device efficiency, making tandem OLEDs increasingly important to industry professionals. The performance of the interconnect layer (i.e., the charge-generating layer) has a crucial impact on the overall performance of the tandem OLED device. Therefore, developing more novel interconnect layer structures to further improve the performance of stacked OLED devices, achieving lower voltage, longer lifespan, and simplified manufacturing processes, is a critical issue that urgently needs to be addressed. Summary of the Invention

[0007] This invention aims to provide a novel tandem organic electroluminescent device (OLED) to solve at least some of the aforementioned problems. The tandem OLED comprises multiple light-emitting units, a second organic layer, and a specific connecting layer, wherein the connecting layer comprises a metal layer and a first organic layer. Specifically, the OLED improves electron injection capability by controlling the difference between the LUMO energy level of the first organic material in the first organic layer and the work function of the metal material in the metal layer; and controls hole injection by controlling the difference between the HOMO energy level of the second organic material in the second organic layer connected to the first organic layer and the LUMO energy level of the first organic material. Using this tandem OLED with the connecting layer and the second organic layer, electrons and holes can be effectively separated and injected, thereby significantly improving device efficiency and achieving low voltage and long lifetime.

[0008] According to one embodiment of the present invention, an organic electroluminescent device is disclosed, comprising:

[0009] First electrode,

[0010] Second electrode,

[0011] and at least two light-emitting units disposed between the first electrode and the second electrode.

[0012] Each of the light-emitting units contains at least one light-emitting layer.

[0013] A connecting layer is further disposed between the at least two light-emitting units. The connecting layer comprises a metal layer and a first organic layer. The first organic layer comprises a first organic material, and the LUMO energy level of the first organic material is LUMO. 第一有机材料 The metal layer comprises at least one metallic material, and the work function of the metallic material is a work function. 金属 The LUMO 第一有机材料 -work function 金属 ≤2.1eV;

[0014] The light-emitting unit in contact with the first organic layer further comprises a second organic layer, and the second organic layer comprises a second organic material and the first organic material; the HOMO energy level of the second organic material is HOMO. 第二有机材料 And HOMO 第二有机材料 -LUMO 第一有机材料 ≥0.3eV.

[0015] According to another embodiment of the present invention, an electronic component comprising the organic electroluminescent device described in the above embodiments is also disclosed.

[0016] The tandem organic electroluminescent device disclosed in this invention comprises multiple light-emitting units, a second organic layer, and a specific connecting layer, wherein the connecting layer comprises a metal layer and a first organic layer. The electroluminescent device enhances electron injection capability by controlling the work function difference between the LUMO of the first organic material in the first organic layer and the work function of the metal in the metal layer; and controls hole injection by controlling the difference between the HOMO energy level of the second organic material in the second organic layer of the light-emitting unit in contact with the first organic layer and the LUMO energy level of the first organic material. Using this tandem electroluminescent device with a connecting layer and a second organic layer, electrons and holes can be effectively separated and injected, thereby significantly improving device efficiency and achieving low voltage and long lifetime. Attached Figure Description

[0017] Figure 1 This is a cross-sectional schematic diagram of the series organic electroluminescent device 100 of the present invention.

[0018] Figure 2 This is a cross-sectional schematic diagram of a single-layer organic electroluminescent device 200. Detailed Implementation

[0019] From a device structure perspective, OLEDs can be divided into conventional single-layer structures and tandem structures (also known as stacked structures). A conventional OLED contains only one light-emitting unit between the anode and cathode, while a tandem OLED consists of multiple stacked light-emitting units. A single light-emitting unit typically contains at least one light-emitting layer, one hole transport layer, and one electron transport layer. The light-emitting unit can further include a hole injection layer, an electron injection layer, a hole blocking layer, and an electron blocking layer. Note that although a conventional single-layer OLED has only one light-emitting unit, this unit can contain multiple light-emitting layers; for example, a single light-emitting unit can contain one yellow light-emitting layer and one blue light-emitting layer. However, each light-emitting unit generally contains one hole transport layer and one electron transport layer. A tandem OLED contains at least two or more light-emitting units, that is, it generally contains at least two or more pairs of hole transport layers and electron transport layers. Here, multiple light-emitting units are arranged in a vertically stacked physical form, thus achieving a series connection characteristic in the circuit, hence the name tandem OLED (from the perspective of circuit connection) or stacked OLED (from the perspective of physical form). In other words, at the same brightness, tandem OLEDs require a lower current density than conventional single-layer OLEDs, thus extending their lifespan. Conversely, at the same current density, tandem OLEDs offer higher brightness than conventional single-layer OLEDs, but the voltage often increases accordingly. Adjacent light-emitting units in a tandem OLED are connected by a connecting layer (also called a charge generation layer), the performance of which directly affects parameters such as voltage, lifespan, and efficiency. Therefore, the connecting layer region must be able to effectively generate holes and electrons and smoothly inject them into the corresponding light-emitting units. It should also have high light transmittance in the visible light range, stable performance, and be easy to fabricate.

[0020] OLEDs can be manufactured on various substrates, such as glass, plastic, and metal. Figure 1 A schematic, non-limiting cross-sectional view of a tandem organic light-emitting device 100 is shown. The figure is not necessarily drawn to scale, and some layers may be omitted as needed. The tandem organic light-emitting device 100 includes a substrate 110, a first electrode 120, a first light-emitting unit 110a, a second light-emitting unit 110b, a second electrode 140, and a connecting layer 130, wherein the connecting layer includes a metal layer 130a and a first organic layer 130b. The substrate 110 can be a substrate with high light transmittance or bendable, such as glass, plastic, or metal. OLED devices can also be structurally classified into bottom-emitting OLED devices and top-emitting OLED devices. Bottom-emitting OLED devices are those where light is emitted from the substrate, while top-emitting OLED devices are those where light is emitted from the second electrode.

[0021] A first electrode 120 is formed on a substrate 110. The first electrode can be a transparent anode of the organic light-emitting device 100, such as indium tin oxide (ITO), indium zinc oxide (IZO), or indium gallium zinc oxide (IGZO). These electrodes are typically used to fabricate bottom-emitting or transparent devices. The first electrode can also be a composite layer that achieves specular reflection, such as a stack of ITO / silver (Ag) / ITO. Such electrodes are typically used to fabricate top-emitting devices. A second electrode 140 is positioned facing the first electrode 120 and is typically the cathode of the organic light-emitting device 100. The second electrode 140 can be one or a combination of two or more elements selected from aluminum, magnesium, silver, gold, calcium, or ytterbium. Aluminum is commonly used as the second electrode for bottom-emitting devices, while magnesium, silver, or magnesium-silver alloys are typically used as the second electrode for top-emitting devices.

[0022] Two light-emitting units 110a and 110b are formed between the first electrode 120 and the second electrode 140. The first light-emitting unit 110a and the second light-emitting unit 110b can emit light of the same color or different colors, such as a mixture of orange and blue light, to emit white light. Each light-emitting unit further includes at least a hole injection layer 111a or 111b, a hole transport layer 112a or 112b, and an electron transport layer 116a or 116b. The second light-emitting unit also includes an electron injection layer 117b. Furthermore, the light-emitting unit may further include one or more of electron blocking layers 113a and 113b and hole blocking layers 115a and 115b. The hole injection layer of the second light-emitting unit can be composed of a single hole injection material or a hole transport material, or it can be composed of an organic hole transport material doped with a dopant, where the dopant can be the first organic material of the first organic layer. The thickness of each layer can be adjusted according to optimization results. Each light-emitting unit may also include one or two light-emitting layers emitting different colors.

[0023] A connecting layer 130 is formed between light-emitting units 110a and 110b. When the series organic light-emitting device 100 is working, the metal layer 130a can provide electrons to the first light-emitting unit 110a in the direction close to the anode 120, forming excitons with the holes injected by the anode 120. At the same time, the first organic layer 130b provides or transmits holes to the second light-emitting unit 110b in the direction close to the cathode 140, forming excitons with the electrons injected by the cathode 140. Therefore, when only one electron and one hole are injected by the cathode 140 and the anode 120, the device itself can generate two excitons, so that the efficiency of the device can theoretically reach up to twice that of a conventional single-layer OLED.

[0024] The connecting layer 130 can be fabricated using any suitable method, such as vacuum phase deposition, vacuum thermal evaporation, sputtering, solution spin coating, inkjet printing, organic vaporization printing, etc. Specifically, the metal 130a can be fabricated in a vacuum chamber specifically for metal fabrication, while the first organic layer 130b can be fabricated in a vacuum chamber specifically for organic material fabrication. This avoids cross-contamination between the metal and organic materials during fabrication, further improving device performance. Simultaneously, using the dopant in the hole injection layer (i.e., the second organic layer) as the first organic material in the first organic layer further reduces the number of evaporation sources. Furthermore, the hole injection layer (i.e., the second organic layer) of the second light-emitting unit typically contacts the first organic layer. Because the same material (the first organic layer material as the dopant) is used, the fabrication process (typically a vapor deposition process) is more continuous, and the interfaces between film layers transition more smoothly.

[0025] The metal layer 130a in the connecting layer 130 is used to generate and transport electrons. Therefore, metal materials have unique advantages and can be selected from Yb, Li, Rb, Cs, Be, Mg, Ca, Sr, Ba, La, Ce, Pr, Nd, Sm, Eu, Y, Mn, Ag metals or combinations of multiple metals. Preferably, the work function of the metal layer 130a is less than 4.0 eV, such as Yb, Mg, Ca, etc. The thickness of the metal layer 130a ranges from 0.1 nm to 20 nm, preferably from 0.1 nm to 5 nm. The thinner the metal layer, the higher the transmittance, which is beneficial to improving the luminous efficiency. In this invention, the transmittance of the connecting layer in the visible light range is greater than 70%; preferably, greater than 80%. Because the metal layer 130a is very thin, it forms a discontinuous film, which maintains excellent electron transport performance while giving the surface a certain roughness so that the first organic material in the first organic layer 130b can better adhere to the metal layer 130a. The first organic material is an organic material capable of hole generation or transport. The first organic material can be a dopant material used in the hole injection layer, or it can be other hole injection or transport layer materials. The LUMO energy level of the first organic material is ≤4.9 eV, more preferably ≤4.7 eV. The thickness of the first organic layer 130b ranges from 0.1 nm to 30 nm, preferably from 0.1 nm to 15 nm. Because the thickness of the first organic layer 130b can be very thin, it also forms a discontinuous thin film with a certain surface roughness, complementing the metal layer 130a.

[0026] The formation process of a metal thin film is as follows: atoms form uniform, tiny, and mobile atomic clusters on the substrate surface; these atomic clusters are also called "islands." These islands then continuously accept newly deposited atoms and merge with other islands, gradually growing larger. During this merging process, new islands gradually form on the vacated substrate surface, and this process continues until all isolated islands are connected, forming a structurally continuous thin film. When the isolated islands are not connected, the resulting film is a discontinuous film. In one exemplary embodiment of this paper, the connecting layer is ytterbium, and the atomic radius of ytterbium is 2.4 angstroms (https: / / www.lookchem.cn / yuansu / 101 / ). When the thickness of the vapor-deposited film is 10 angstroms, it is equivalent to a thickness of only two atoms. Two atoms can only form isolated islands, and the resulting film is a discontinuous film.

[0027] As used herein, "top" means furthest from the substrate, and "bottom" means closest to the substrate. When the first layer is described as being "disposed" on the second layer, the first layer is positioned further from the substrate. Unless it is specified that the first layer "contacts" the second layer, other layers may exist between the first and second layers. For example, even if various organic layers exist between the cathode and anode, the cathode can still be described as being "disposed" on the "anode." Similarly, the first layer "contacting" the second layer indicates that there are no other layers between the first and second layers.

[0028] In this article, transmittance refers to the percentage of transmitted light flux through the tested thin film measured in the visible light range (380-780 nm) relative to its incident light flux. The transmittance of different thin films typically varies with the wavelength of the incident light; the transmittance described in this article refers to the maximum transmittance in the visible light range.

[0029] In this document, the term "light-emitting unit" refers to a unit of organic material layer that emits light when a voltage or current is applied. The light-emitting unit may include one or more light-emitting layers. The light-emitting unit typically also includes one or more organic material layers for injecting or transporting charge. For example, in addition to the light-emitting layer, the light-emitting unit may further include at least a hole injection layer, a hole transport layer, an electron blocking layer, a hole blocking layer, an electron transport layer, and an electron injection layer. For example, in an exemplary embodiment of the present invention, the light-emitting unit near the anode is composed of, in sequence, a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, a hole blocking layer, and an electron transport layer; the light-emitting unit near the cathode is composed of a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, a hole blocking layer, an electron transport layer group, and an electron injection layer. In one embodiment, an OLED device can be described as having an "organic layer" disposed between the cathode and the anode. This organic layer may include one or more layers.

[0030] In this article, the work function of a metallic material refers to the minimum energy required to move an electron from the interior of the material to its surface. All "metal work functions" in this article are expressed as absolute values ​​(positive values), meaning that the higher the value, the greater the energy required to pull an electron to a vacuum level. As stated in this article, "large" or "small" in the "metal work function" refers to the absolute value. For example, "metal work function greater than 5.0 eV" means that more than 5.0 eV of energy is required to pull an electron to a vacuum level.

[0031] In this paper, the HOMO (highest occupied orbital) and LUMO (lowest unoccupied orbital) energy levels of organic materials were measured using the electrochemical cyclic voltammetry method. All "HOMO" and "LUMO" energy levels are expressed as their absolute values ​​(positive values); the larger the value, the deeper the energy level. The statement that an energy level is greater than a certain number indicates that the energy level is numerically larger than that number, i.e., it has a deeper energy level. For example, "the HOMO energy level of the second organic material ≥ 5.1 eV" means that the absolute value of the HOMO energy level of the second organic material is greater than or equal to 5.1 eV. In this paper, the energy difference between the LUMO of the first organic material and the HOMO of the second organic material is defined as "HOMO energy level". 第二有机材料 -LUMO 第一有机材料 Since the HOMO levels of transport materials are typically deeper, this difference is generally positive. The energy level difference between the LUMO of the first organic material and the work function of the metal is defined as "LUMO". 第一有机材料属- Work function 金属 ".

[0032] As used in this article, the "connecting layer" is a layer placed between two light-emitting units to provide electron and hole interaction, also known as a charge generation layer. It consists of a metal layer and a first organic layer, wherein the metal layer is in contact with the electron transport layer or electron injection layer of one light-emitting unit, and the first organic layer is in contact with the hole injection layer or hole transport layer of the adjacent light-emitting unit.

[0033] Devices prepared according to embodiments of the present invention can be incorporated into various consumer products having one or more electronic component modules (or units). Some examples of such consumer products include flat panel displays, monitors, medical monitors, televisions, billboards, lights for indoor or outdoor lighting and / or signaling, head-up displays, fully or partially transparent displays, flexible displays, smartphones, tablet computers, phablets, wearable devices, smartwatches, laptop computers, digital cameras, portable camcorders, viewfinders, microdisplays, 3D displays, vehicle displays, and taillights.

[0034] Definition of the term "substituent group"

[0035] Halogens or halides—as used herein—include fluorine, chlorine, bromine, and iodine.

[0036] Alkyl – as used herein, includes straight-chain and branched alkyl groups. An alkyl group can be an alkyl group having 1 to 20 carbon atoms, preferably an alkyl group having 1 to 12 carbon atoms, and more preferably an alkyl group having 1 to 6 carbon atoms. Examples of alkyl groups include methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecanyl, n-hexadecyl, n-heptadecyl, n-octadecyl, neopentyl, 1-methylpentyl, 2-methylpentyl, 1-pentylhexyl, 1-butylpentyl, 1-heptyloctyl, and 3-methylpentyl. Among the above, methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, neopentyl, and n-hexyl are preferred. Additionally, the alkyl group may optionally be substituted.

[0037] Cycloalkyl – as used herein, comprises cyclic alkyl groups. The cycloalkyl group can be a cycloalkyl group having 3 to 20 carbon atoms, preferably a cycloalkyl group having 4 to 10 carbon atoms. Examples of cycloalkyl groups include cyclobutyl, cyclopentyl, cyclohexyl, 4-methylcyclohexyl, 4,4-dimethylcyclohexyl, 1-adamantyl, 2-adamantyl, 1-norbornyl, 2-norbornyl, etc. Among the above, cyclopentyl, cyclohexyl, 4-methylcyclohexyl, and 4,4-dimethylcyclohexyl are preferred. Furthermore, the cycloalkyl group may optionally be substituted.

[0038] Heteroalkyl – as used herein, a heteroalkyl group comprises one or more carbon atoms in an alkyl chain that are replaced by heteroatoms selected from the group consisting of nitrogen, oxygen, sulfur, selenium, phosphorus, silicon, germanium, and boron atoms. The heteroalkyl group can be a heteroalkyl group having 1 to 20 carbon atoms, preferably a heteroalkyl group having 1 to 10 carbon atoms, and more preferably a heteroalkyl group having 1 to 6 carbon atoms. Examples of heteroalkyl groups include methoxymethyl, ethoxymethyl, ethoxyethyl, methylthiomethyl, ethylthiomethyl, ethylthioethyl, methoxymethoxymethyl, ethoxymethoxymethyl, ethoxyethoxyethyl, hydroxymethyl, hydroxyethyl, hydroxypropyl, mercaptomethyl, mercaptoethyl, mercaptopropyl, aminomethyl, aminoethyl, aminopropyl, dimethylaminomethyl, trimethylgermanylmethyl, trimethylgermanylethyl, trimethylgermanylisopropyl, dimethylethylgermanylmethyl, dimethylisopropylgermanylmethyl, tert-butyldimethylgermanylmethyl, triethylgermanylmethyl, triethylgermanylethyl, triisopropylgermanylmethyl, triisopropylgermanylethyl, trimethylsilylmethyl, trimethylsilylethyl, trimethylsilylisopropyl, triisopropylsilylmethyl, triisopropylsilylethyl. Additionally, heteroalkyl groups may optionally be substituted.

[0039] Alkenyl – as used herein, encompasses straight-chain, branched, and cyclic olefinic groups. An alkenyl group can be an alkenyl group containing 2 to 20 carbon atoms, preferably an alkenyl group having 2 to 10 carbon atoms. Examples of alkenyl groups include vinyl, propenyl, 1-butenyl, 2-butenyl, 3-butenyl, 1,3-butadienyl, 1-methylvinyl, styryl, 2,2-diphenylvinyl, 1,2-diphenylvinyl, 1-methylallyl, 1,1-dimethylallyl, 2-methylallyl, 1-phenylallyl, 2-phenylallyl, 3-phenylallyl, 3,3-diphenylallyl, 1,2-dimethylallyl, 1-phenyl-1-butenyl, 3-phenyl-1-butenyl, cyclopentenyl, cyclopentadienyl, cyclohexenyl, cycloheptenyl, cyclohepttrienyl, cyclooctenyl, cyclooctatetraenyl, and norbornyl. In addition, the alkenyl group can be optionally substituted.

[0040] Alkynyl – as used herein, encompasses straight-chain alkynyl groups. An alkynyl group can be one containing 2 to 20 carbon atoms, preferably 2 to 10 carbon atoms. Examples of alkynyl groups include ethynyl, propynyl, propynyl, 1-butynyl, 2-butynyl, 3-butynyl, 1-pentynyl, 2-pentynyl, 3,3-dimethyl-1-butynyl, 3-ethyl-3-methyl-1-pentynyl, 3,3-diisopropyl-1-pentynyl, phenylethynyl, phenylpropynyl, etc. Among the above, ethynyl, propynyl, propynyl, 1-butynyl, 2-butynyl, 3-butynyl, 1-pentynyl, and phenylethynyl are preferred. Furthermore, the alkynyl group may be optionally substituted.

[0041] Aryl or aromatic group – as used herein, both non-fused and fused systems are considered. The aryl group can be an aryl group having 6 to 30 carbon atoms, preferably an aryl group having 6 to 20 carbon atoms, and more preferably an aryl group having 6 to 12 carbon atoms. Examples of aryl groups include phenyl, biphenyl, terphenyl, triphenylene, tetraphenylene, naphthalene, anthracene, fenene, fluorene, pyrene, etc. Perylene and azulene, preferably phenyl, biphenyl, terphenyl, triphenylene, fluorene, and naphthalene. Examples of non-fused aryl groups include phenyl, biphenyl-2-yl, biphenyl-3-yl, biphenyl-4-yl, p-terphenyl-4-yl, p-terphenyl-3-yl, p-terphenyl-2-yl, m-terphenyl-4-yl, m-terphenyl-3-yl, m-terphenyl-2-yl, o-tolyl, m-tolyl, p-tolyl, p-(2-phenylpropyl)phenyl, 4'-methyldiphenyl, 4”-tert-butyl-p-terphenyl-4-yl, o-cumyl, m-cumyl, p-cumyl, 2,3-xylyl, 3,4-xylyl, 2,5-xylyl, mesitylene, and m-tetraphenyl. Additionally, the aryl group may optionally be substituted.

[0042] Heterocyclic groups or heterocycles – as used herein, consider non-aromatic cyclic groups. Non-aromatic heterocyclic groups include saturated heterocyclic groups having 3-20 ring atoms and unsaturated non-aromatic heterocyclic groups having 3-20 ring atoms, wherein at least one ring atom is selected from the group consisting of nitrogen, oxygen, sulfur, selenium, silicon, phosphorus, germanium, and boron atoms. Preferred non-aromatic heterocyclic groups are those having 3 to 7 ring atoms, including at least one heteroatom such as nitrogen, oxygen, silicon, or sulfur. Examples of non-aromatic heterocyclic groups include ethylene oxide, oxetane, tetrahydrofuranyl, tetrahydropyranyl, dioxopentacyclic, dioxahexacyclic, acridineyl, dihydropyrroleyl, tetrahydropyrroleyl, piperidinyl, oxazolidinyl, morpholinyl, piperazineyl, oxetane-heptanetrienyl, thioheptanetrienyl, azirane-heptanetrienyl, and tetrahydrothiorroleyl. In addition, the heterocyclic group can be optionally substituted.

[0043] Heteroaryl – as used herein – can be a non-fused or fused heteroaryl group comprising 1 to 5 heteroatoms, wherein at least one heteroatom is selected from the group consisting of nitrogen, oxygen, sulfur, selenium, silicon, phosphorus, germanium, and boron. Isoaryl also refers to heteroaryl. Heteroaryl can be a heteroaryl having 3 to 30 carbon atoms, preferably a heteroaryl having 3 to 20 carbon atoms, and more preferably a heteroaryl having 3 to 12 carbon atoms. Suitable heteroaryl groups include dibenzothiophene, dibenzofuran, dibenzoselenophene, furan, thiophene, benzofuran, benzothiophene, benzoselenophene, carbazole, indolecarbazole, pyridineindole, pyrrolopyridine, pyrazole, imidazole, triazole, oxazole, thiazole, oxadiazole, oxtriazole, dioxazole, thiadiazol, pyridine, pyrazine, pyrazine, triazine, oxazine, oxthiazine, oxadiazine, indole, benzimidazole, indazole, indoxazine, benzoxazole, benzoisoxazole, benzothiazole, quinoline, isoquinoline Phosphine, cyclophosphine, quinazoline, quinoxaline, naphthidine, phthalazine, pteridine, xanthan, acridine, phenazine, phenothiazine, benzofuranopyridine, furanodipyridine, benzothiophenopyridine, thiophenodipyridine, benzoselenophenopyridine, selenobenzodipyridine, preferably dibenzothiophene, dibenzofuran, dibenzoselenophene, carbazole, indolocarbazole, imidazole, pyridine, triazine, benzimidazole, 1,2-azaborane, 1,3-azaborane, 1,4-azaborane, boronazole and its aza analogues. Additionally, the heteroaryl group may optionally be substituted.

[0044] Alkoxy groups—as used herein—are represented by -O-alkyl, -O-cycloalkyl, -O-heteroalkyl, or -O-heterocyclic groups. Examples and preferred examples of alkyl, cycloalkyl, heteroalkyl, and heterocyclic groups are the same as described above. An alkoxy group can be an alkoxy group having 1 to 20 carbon atoms, preferably an alkoxy group having 1 to 6 carbon atoms. Examples of alkoxy groups include methoxy, ethoxy, propoxy, butoxy, pentoxy, hexoxy, cyclopropyloxy, cyclobutyloxy, cyclopentoxy, cyclohexyloxy, tetrahydrofuranyloxy, tetrahydropyranyloxy, methoxypropyloxy, ethoxyethyloxy, methoxymethyloxy, and ethoxymethyloxy. Additionally, alkoxy groups may optionally be substituted.

[0045] Aryloxy group – as used herein, is represented by -O-aryl or -O-heteroaryl. Examples and preferred examples of aryl and heteroaryl groups are the same as described above. The aryloxy group can be an aryloxy group having 6 to 30 carbon atoms, preferably an aryloxy group having 6 to 20 carbon atoms. Examples of aryloxy groups include phenoxy and biphenyloxy groups. Additionally, the aryloxy group may optionally be substituted.

[0046] Arylalkyl – as used herein, encompasses aryl-substituted alkyl groups. An arylalkyl group can be an arylalkyl group having 7 to 30 carbon atoms, preferably an arylalkyl group having 7 to 20 carbon atoms, and more preferably an arylalkyl group having 7 to 13 carbon atoms. Examples of arylalkyl groups include benzyl, 1-phenylethyl, 2-phenylethyl, 1-phenylisopropyl, 2-phenylisopropyl, phenyl tert-butyl, α-naphthylmethyl, 1-α-naphthyl-ethyl, 2-α-naphthylethyl, 1-α-naphthylisopropyl, 2-α-naphthylisopropyl, β-naphthylmethyl, 1-β-naphthyl-ethyl, 2-β-naphthyl-ethyl, 1-β-naphthylisopropyl, 2-β-naphthylisopropyl, p-methylbenzyl, m-methylbenzyl The compounds include alkyl groups, such as o-methylbenzyl, p-chlorobenzyl, m-chlorobenzyl, o-chlorobenzyl, p-bromobenzyl, m-bromobenzyl, o-bromobenzyl, p-iodobenzyl, m-iodobenzyl, o-iodobenzyl, p-hydroxybenzyl, m-hydroxybenzyl, o-hydroxybenzyl, p-aminobenzyl, m-aminobenzyl, o-aminobenzyl, p-nitrobenzyl, m-nitrobenzyl, o-nitrobenzyl, p-cyanobenzyl, m-cyanobenzyl, o-cyanobenzyl, 1-hydroxy-2-phenylisopropyl, and 1-chloro-2-phenylisopropyl. Among the above, benzyl, p-cyanobenzyl, m-cyanobenzyl, o-cyanobenzyl, 1-phenylethyl, 2-phenylethyl, 1-phenylisopropyl, and 2-phenylisopropyl are preferred. Additionally, the alkyl group may optionally be substituted.

[0047] Alkylsilyl – as used herein, encompasses alkyl-substituted silyl groups. The alkylsilyl group can be an alkylsilyl group having 3 to 20 carbon atoms, preferably an alkylsilyl group having 3 to 10 carbon atoms. Examples of alkylsilyl groups include trimethylsilyl, triethylsilyl, methyldiethylsilyl, ethyldimethylsilyl, tripropylsilyl, tributylsilyl, triisopropylsilyl, methyldiisopropylsilyl, dimethylisopropylsilyl, tritert-butylsilyl, triisobutylsilyl, dimethyltert-butylsilyl, and methylditert-butylsilyl. Furthermore, the alkylsilyl group may optionally be substituted.

[0048] Arylsilane – as used herein, encompasses at least one aryl-substituted silane group. The arylsilane can be an arylsilane having 6 to 30 carbon atoms, preferably an arylsilane having 8 to 20 carbon atoms. Examples of arylsilanes include triphenylsilyl, phenyldiphenylsilyl, diphenylbiphenylsilyl, phenyldiethylsilyl, diphenylethylsilyl, phenyldimethylsilyl, diphenylmethylsilyl, phenyldiisopropylsilyl, diphenylisopropylsilyl, diphenylbutylsilyl, diphenylisobutylsilyl, and diphenyltert-butylsilyl. Additionally, the arylsilane may optionally be substituted.

[0049] Alkylgermanium group – as used herein, encompasses alkyl-substituted germanium groups. The alkylgermanium group can be an alkylgermanium group having 3 to 20 carbon atoms, preferably an alkylgermanium group having 3 to 10 carbon atoms. Examples of alkylgermanium groups include trimethylgermanium, triethylgermanium, methyldiethylgermanium, ethyldimethylgermanium, tripropylgermanium, tributylgermanium, triisopropylgermanium, methyldiisopropylgermanium, dimethylisopropylgermanium, tritert-butylgermanium, triisobutylgermanium, dimethyltert-butylgermanium, and methylditert-butylgermanium. Furthermore, the alkylgermanium group may optionally be substituted.

[0050] Arylgermanium – as used herein, encompasses a germanium group substituted with at least one aryl or heteroaryl group. The arylgermanium group can be an arylgermanium group having 6 to 30 carbon atoms, preferably an arylgermanium group having 8 to 20 carbon atoms. Examples of arylgermanium groups include triphenylgermanium, phenyldiphenylgermanium, diphenylbiphenylgermanium, phenyldiethylgermanium, diphenylethylgermanium, phenyldimethylgermanium, diphenylmethylgermanium, phenyldiisopropylgermanium, diphenylisopropylgermanium, diphenylbutylgermanium, diphenylisobutylgermanium, and diphenyltert-butylgermanium. Additionally, the arylgermanium group may optionally be substituted.

[0051] The term "aza" in azadibenzofuran, azadibenzothiophene, etc., refers to the substitution of one or more CH groups in the corresponding aromatic segment by a nitrogen atom. For example, azatriphenylene includes dibenzo[f,h]quinoxaline, dibenzo[f,h]quinoline, and other analogs having two or more nitrogen atoms in the ring system. Other nitrogen analogs of the aforementioned aza derivatives will readily conceive of those skilled in the art, and all such analogs are identified as being included in the terminology used herein.

[0052] In this disclosure, unless otherwise defined, the term "substituted alkyl", "substituted cycloalkyl", "substituted heteroalkyl", "substituted heterocyclic", "substituted aralkyl", "substituted alkoxy", "substituted aryl", "substituted alkenyl", "substituted alkynyl", "substituted heteroaryl", "substituted alkylsilyl", "substituted arylsilyl", "substituted alkylgermanium", "substituted arylgermanium", "substituted amino", "substituted acyl", "substituted carbonyl", and "substituted carboxylic acid" are used interchangeably. The substituted ester group, substituted sulfinyl group, substituted sulfonyl group, substituted phosphinyl group refers to any one of the following groups: alkyl, cycloalkyl, heteroalkyl, heterocyclic, aralkyl, alkoxy, aryloxy, alkenyl, alkynyl, aryl, heteroaryl, alkylsilyl, arylsilyl, alkylgermanium, arylgermanium, amino, acyl, carbonyl, carboxylic acid, ester, sulfinyl, sulfonyl, and phosphinyl groups. One or more groups can be selected from deuterium, halogen, unsubstituted alkyl groups having 1-20 carbon atoms. Cycloalkyl groups having 3-20 carbon atoms, unsubstituted heteroalkyl groups having 1-20 carbon atoms, unsubstituted heterocyclic groups having 3-20 carbon atoms, unsubstituted aralkyl groups having 7-30 carbon atoms, unsubstituted alkoxy groups having 1-20 carbon atoms, unsubstituted aryloxy groups having 6-30 carbon atoms, unsubstituted alkenyl groups having 2-20 carbon atoms, unsubstituted alkynyl groups having 2-20 carbon atoms, and unsubstituted alkyne groups having 6-30 carbon atoms. Aryl, unsubstituted heteroaryl with 3-30 carbon atoms, unsubstituted alkylsilyl with 3-20 carbon atoms, unsubstituted arylsilyl with 6-20 carbon atoms, unsubstituted alkylgermanium with 3-20 carbon atoms, unsubstituted arylgermanium with 6-20 carbon atoms, unsubstituted amino, acyl, carbonyl, carboxylic acid, ester, cyano, isocyano, mercapto, sulfinyl, sulfonyl, phosphine, and combinations thereof with 0-20 carbon atoms.

[0053] It should be understood that when a molecular segment is described as a substituent or otherwise attached to another part, its name may be written according to whether it is a segment (e.g., phenyl, phenylene, naphthyl, dibenzofuranyl) or according to whether it is a whole molecule (e.g., benzene, naphthalene, dibenzofuran). As used herein, these different ways of specifying substituents or attaching segments are considered equivalent.

[0054] In the compounds mentioned in this disclosure, hydrogen atoms can be partially or completely replaced by deuterium. Other atoms such as carbon and nitrogen can also be replaced by their other stable isotopes. Substitution with other stable isotopes in the compounds is likely preferred due to their ability to enhance device efficiency and stability.

[0055] In the compounds mentioned in this disclosure, polysubstituted means including disubstituted, up to the maximum range of available substitutions. When a substituent in a compound mentioned in this disclosure represents polysubstituted (including disubstituted, trisubstituted, tetrasubstituted, etc.), it means that the substituent can be present at multiple available substitution positions on its linkage structure. The substituent present at multiple available substitution positions can be the same structure or different structures.

[0056] In the compounds mentioned in this disclosure, unless explicitly specified, for example, that adjacent substituents can optionally connect to form a ring, adjacent substituents in the compounds cannot connect to form a ring. In the compounds mentioned in this disclosure, the optional connection of adjacent substituents to form a ring includes both cases where adjacent substituents can connect to form a ring and cases where adjacent substituents do not connect to form a ring. When adjacent substituents can optionally connect to form a ring, the formed ring can be a monocyclic or polycyclic ring (including spirocyclic, bridged, fused rings, etc.), as well as an alicyclic, heterocyclic, aromatic, or heteroaromatic ring. In this context, adjacent substituents can refer to substituents bonded to the same atom, substituents bonded to carbon atoms directly bonded to each other, or substituents bonded to carbon atoms further away. Preferably, adjacent substituents refer to substituents bonded to the same carbon atom and substituents bonded to carbon atoms directly bonded to each other.

[0057] In this invention, the number of ring atoms refers to the number of atoms constituting the ring itself in a compound whose atoms are bonded together in a cyclic structure (e.g., monocyclic compounds, fused ring compounds, cross-linked compounds, carbocyclic compounds, heterocyclic compounds). When the ring is substituted with a substituent, the atoms contained in the substituent are not included in the number of ring atoms. Unless otherwise specified, the term "number of ring atoms" as used herein has the same meaning.

[0058] The statement that adjacent substituents can optionally connect to form a ring is also intended to be understood as referring to two substituents bonded to the same carbon atom connecting to each other via chemical bonds to form a ring, as exemplified by the following formula:

[0059]

[0060] The statement that adjacent substituents can optionally link to form a ring is also intended to be understood as referring to two substituents bonded to carbon atoms directly bonded to each other forming a ring through chemical bonds, as exemplified by the following formula:

[0061]

[0062] The statement that adjacent substituents can optionally connect to form a ring is also intended to be understood as referring to two substituents bonded to a further distant carbon atom connecting to each other by chemical bonds to form a ring, which can be exemplified by the following formula:

[0063]

[0064] Furthermore, the statement that adjacent substituents can optionally connect to form a ring is also intended to mean that, in the case where one of the two adjacent substituents represents hydrogen, the second substituent bonds to the position where the hydrogen atom is bonded, thereby forming a ring. This is illustrated by the following example:

[0065]

[0066] According to one embodiment of the present invention, an organic electroluminescent device is disclosed, comprising:

[0067] First electrode,

[0068] Second electrode,

[0069] and at least two light-emitting units disposed between the first electrode and the second electrode.

[0070] Each of the light-emitting units contains at least one light-emitting layer.

[0071] A connecting layer is further disposed between the at least two light-emitting units. The connecting layer comprises a metal layer and a first organic layer. The first organic layer comprises a first organic material, and the LUMO energy level of the first organic material is LUMO. 第一有机材料 The metal layer comprises at least one metallic material, and the work function of the metallic material is a work function. 金属 The LUMO 第一有机材料 -work function 金属 ≤2.1eV;

[0072] The light-emitting unit in contact with the first organic layer further comprises a second organic layer, and the second organic layer comprises a second organic material and the first organic material; the HOMO energy level of the second organic material is HOMO. 第二有机材料 And HOMO 第二有机材料 -LUMO 第一有机材料 ≥0.3eV.

[0073] According to one embodiment of the present invention, the LUMO energy level of the first organic material is ≤4.7 eV.

[0074] According to one embodiment of the present invention, the first organic material has a structure represented by one of Formulas 1 to 3:

[0075]

[0076] In Equation 1, Equation 2 or Equation 3

[0077] E is selected from CR1 each time it appears, either identically or differently;

[0078] Each time X appears, it is selected from the group consisting of NR', CR”R”', O, S and Se, either the same or different.

[0079] Each time ring A appears, it is either the same or different five-membered heterocycle, and the five-membered heterocycle contains an intracyclic double bond, at least one N atom and at least one Q atom;

[0080] Q is chosen freely from O, S, Se, and NR each time it appears, either the same or different. N The group formed;

[0081] The same or different occurrences of R each indicate monosubstitution, polysubstitution, or no substitution;

[0082] R, R1, R', R", R"', R N Each time it appears, it is selected from the group consisting of the following groups, either identically or differently: hydrogen, deuterium, halogen, nitrosyl, nitro, acyl, carbonyl, carboxylic acid, ester, cyano, isocyanate, SCN, OCN, SF5, borane, sulfinyl, sulfonyl, phosphooxy, hydroxyl, mercapto, substituted or unsubstituted alkyl groups having 1-20 carbon atoms, substituted or unsubstituted cycloalkyl groups having 3-20 ring carbon atoms, substituted or unsubstituted heteroalkyl groups having 1-20 carbon atoms, substituted or unsubstituted heterocyclic groups having 3-20 ring atoms, substituted or unsubstituted aralkyl groups having 7-30 carbon atoms, substituted or unsubstituted groups having 1-20 carbon atoms. Alkoxy groups with 6 to 30 carbon atoms, substituted or unsubstituted aryloxy groups with 2 to 20 carbon atoms, substituted or unsubstituted alkynyl groups with 2 to 20 carbon atoms, substituted or unsubstituted aryl groups with 6 to 30 carbon atoms, substituted or unsubstituted heteroaryl groups with 3 to 30 carbon atoms, substituted or unsubstituted alksilyl groups with 3 to 20 carbon atoms, substituted or unsubstituted arylsilyl groups with 6 to 20 carbon atoms, substituted or unsubstituted alkylgermanium groups with 3 to 20 carbon atoms, substituted or unsubstituted arylgermanium groups with 6 to 20 carbon atoms, and combinations thereof;

[0083] Furthermore, at least one of the substituents R, R1, R', R” and R”' is a group having at least one electron-withdrawing group;

[0084] Adjacent substituents R, R', R", R"' can optionally connect to form a ring.

[0085] In this embodiment, adjacent substituents R, R', R", and R"' can optionally connect to form a ring, which is intended to represent adjacent substituent groups, such as adjacent substituent R, adjacent substituents R" and R'", adjacent substituents R and R", adjacent substituents R and R'", and adjacent substituents R and R', any one or more of these adjacent substituent groups can connect to form a ring. Obviously, these adjacent substituents may also not connect to form a ring.

[0086] According to one embodiment of the present invention, the first organic material has a structure represented by Formula 1 or Formula 2.

[0087] According to one embodiment of the present invention, the first organic material has a structure represented by Formula 3-1:

[0088]

[0089] Wherein, X is selected from NR', CR”R”', O, S or Se each time it appears;

[0090] At least one of R, R', R” and R”' is a group having at least one electron-withdrawing group;

[0091] Q is chosen freely from O, S, Se, and NR each time it appears, either the same or different. N The group formed;

[0092] R, R', R", R"', R N Each time it appears, it is selected from the group consisting of the following groups, either identically or differently: hydrogen, deuterium, halogen, nitrosyl, nitro, acyl, carbonyl, carboxylic acid, ester, cyano, isocyanate, SCN, OCN, SF5, borane, sulfinyl, sulfonyl, phosphooxy, hydroxyl, mercapto, substituted or unsubstituted alkyl groups having 1-20 carbon atoms, substituted or unsubstituted cycloalkyl groups having 3-20 ring carbon atoms, substituted or unsubstituted heteroalkyl groups having 1-20 carbon atoms, substituted or unsubstituted heterocyclic groups having 3-20 ring atoms, substituted or unsubstituted aralkyl groups having 7-30 carbon atoms, substituted or unsubstituted groups having 1-20 carbon atoms. Alkoxy groups with 6 to 30 carbon atoms, substituted or unsubstituted aryloxy groups with 2 to 20 carbon atoms, substituted or unsubstituted alkynyl groups with 2 to 20 carbon atoms, substituted or unsubstituted aryl groups with 6 to 30 carbon atoms, substituted or unsubstituted heteroaryl groups with 3 to 30 carbon atoms, substituted or unsubstituted alkylsilyl groups with 3 to 20 carbon atoms, substituted or unsubstituted arylsilyl groups with 6 to 20 carbon atoms, substituted or unsubstituted alkylgermanium groups with 3 to 20 carbon atoms, substituted or unsubstituted arylgermanium groups with 6 to 20 carbon atoms, and combinations thereof.

[0093] According to one embodiment of the present invention, in Formula 1, Formula 2, Formula 3 or Formula 3-1, X is selected from CR”R”' or NR’ each time it appears, and each of R’, R” and R”' is a group having at least one electron-withdrawing group.

[0094] According to one embodiment of the present invention, in Formula 1, Formula 2, Formula 3 or Formula 3-1, X is selected from CR”R”' or NR’ each time it appears, and each of R, R’, R” and R”' is a group having at least one electron-withdrawing group.

[0095] According to one embodiment of the present invention, in formula 1, formula 2, formula 3 or formula 3-1, X is selected from the group consisting of the following structures each time it appears:

[0096]

[0097] According to one embodiment of the present invention, in formula 1, formula 2, formula 3 or formula 3-1, X is selected from X-1.

[0098] According to one embodiment of the present invention, in formula 1, formula 2, formula 3 or formula 3-1, Q is selected from O or S each time it appears.

[0099] According to one embodiment of the present invention, wherein in Formula 1, Formula 2, Formula 3 or Formula 3-1, R, R1, each time appearing, is selected from the group consisting of: hydrogen, deuterium, halogen, nitrosyl, nitro, acyl, carbonyl, carboxylic acid, ester, cyano, isocyanate, SCN, OCN, SF5, borane, sulfinyl, sulfonyl, phosphoxy, unsubstituted alkyl having 1-20 carbon atoms, unsubstituted cycloalkyl having 3-20 cyclic carbon atoms, unsubstituted alkoxy having 1-20 carbon atoms, unsubstituted alkenyl having 2-20 carbon atoms, unsubstituted alkenyl having 6 carbon atoms, and so on. aryl groups having -30 carbon atoms, unsubstituted heteroaryl groups having 3-30 carbon atoms, and any of the following groups substituted by one or more of halogen, nitroso, nitro, acyl, carbonyl, carboxylic acid, ester, cyano, isocyano, SCN, OCN, SF5, borane, sulfinyl, sulfonyl, and phosphoxy groups: alkyl groups having 1-20 carbon atoms, cycloalkyl groups having 3-20 cyclic carbon atoms, alkoxy groups having 1-20 carbon atoms, alkenyl groups having 2-20 carbon atoms, aryl groups having 6-30 carbon atoms, heteroaryl groups having 3-30 carbon atoms, and combinations thereof.

[0100] According to one embodiment of the present invention, wherein in Formula 1, Formula 2, Formula 3 or Formula 3-1, R, R1, each time appearing, is selected from the group consisting of: hydrogen, deuterium, methyl, isopropyl, NO2, SO2CH3, SCF3, C2F5, OC2F5, OCH3, diphenylmethylsilyl, phenyl, methoxyphenyl, p-methylphenyl, 2,6-diisopropylphenyl, biphenyl, polyfluorophenyl, difluoropyridyl, nitrophenyl, dimethylthiazolyl, substituted by one or more of CN or CF3. Vinyl, ethynyl group substituted with one of CN or CF3, dimethylphosphoxy, diphenylphosphoxy, F, CF3, OCF3, SF5, SO2CF3, cyano, isocyano, SCN, OCN, trifluoromethylphenyl, trifluoromethoxyphenyl, bis(trifluoromethyl)phenyl, bis(trifluoromethoxy)phenyl, 4-cyanotetrafluorophenyl, phenyl or biphenyl group substituted with one or more of F, CN or CF3, tetrafluoropyridyl, pyrimidinyl, triazine, diphenylborane, oxaboxanthracene, and combinations thereof.

[0101] According to one embodiment of the present invention, the first organic material is selected from the group consisting of the following structures:

[0102]

[0103]

[0104]

[0105]

[0106] According to one embodiment of the present invention, the metal material in the metal layer is selected from the group consisting of: Yb, Li, Rb, Cs, Be, Mg, Ca, Sr, Ba, La, Ce, Pr, Nd, Sm, Eu, Y, Mn, Ag, and combinations of the above metals.

[0107] According to one embodiment of the present invention, the metal material in the metal layer is Yb.

[0108] According to one embodiment of the present invention, the work function of the metal material of the metal layer is less than 4.0 eV.

[0109] According to one embodiment of the present invention, the metal layer is formed of one elemental metal or of two or more elemental metals.

[0110] According to one embodiment of the present invention, the thickness of the metal layer is between 0.1 nm and 20 nm.

[0111] According to one embodiment of the present invention, the thickness of the metal layer is between 0.1 nm and 5 nm.

[0112] According to one embodiment of the present invention, wherein the LUMO 第一有机材料 -work function 金属 <2.05eV.

[0113] According to one embodiment of the present invention, the thickness of the first organic layer is between 0.1 nm and 30 nm.

[0114] According to one embodiment of the present invention, the thickness of the first organic layer is between 0.1 nm and 15 nm.

[0115] According to one embodiment of the present invention, in the second organic layer, the first organic material accounts for 4% to 49% of the total mass of the second organic layer.

[0116] According to one embodiment of the present invention, the first organic material accounts for 5% to 35% of the total mass of the second organic layer in the second organic layer.

[0117] According to one embodiment of the present invention, in the second organic layer, the first organic material accounts for 5% to 30% of the total mass of the second organic layer.

[0118] According to one embodiment of the present invention, at least one of the first organic layer and the metal layer forms a discontinuous thin film.

[0119] According to one embodiment of the present invention, the first organic layer is in direct contact with the second organic layer.

[0120] According to one embodiment of the present invention, wherein the HOMO 第二有机材料 -LUMO 第一有机材料 ≤0.8eV.

[0121] According to one embodiment of the present invention, wherein the HOMO 第二有机材料 -LUMO 第一有机材料 ≤0.6eV.

[0122] According to one embodiment of the present invention, the HOMO energy level of the second organic material is ≥5.1 eV.

[0123] According to one embodiment of the present invention, the transmittance of the connecting layer in the visible light range is greater than 70%.

[0124] According to one embodiment of the present invention, the transmittance of the connecting layer in the visible light range is greater than 80%.

[0125] According to one embodiment of the present invention, the at least two light-emitting units may emit light of the same color or different colors.

[0126] According to another embodiment of the present invention, an electronic component comprising an organic electroluminescent device is also disclosed, wherein the specific structure of the organic electroluminescent device is as shown in any of the foregoing embodiments.

[0127] According to one embodiment of the present invention, the electronic component is a display component or a lighting component.

[0128] In this paper, the LUMO and HOMO energy levels of the materials were obtained by cyclic voltammetry and their absolute values ​​were taken. The tests were conducted using a CorrTest CS120 electrochemical workstation manufactured by Wuhan CorrTest Instruments Co., Ltd., employing a three-electrode system: a platinum disk electrode as the working electrode, an Ag / AgNO3 electrode as the reference electrode, and a platinum wire electrode as the auxiliary electrode. Anhydrous DCM was used as the solvent, and 0.1 mol / L tetrabutylammonium hexafluorophosphate was used as the supporting electrolyte. The test compound was prepared by adding 10... -3 For the mol / L solution, nitrogen gas was bubbled into the solution for 10 min to remove oxygen before the test. Instrument parameter settings: scan rate 100 mV / s, potential interval 0.5 mV, test window -1 V to 1 V.

[0129] Table 1 lists the work function of the metallic material Yb in the connecting layer, as well as the energy level information of compounds 1-2, PD-2, and the second organic material compound HT-7.

[0130] Table 1. Work function of metallic material Yb and energy level information of compounds 1-2, PD-2 and HT-7.

[0131]

[0132] The specific structures of compounds 1-2, PD-2, and HT-7 are as follows:

[0133]

[0134] Specifically, the metal used in the device embodiments of the present invention is Yb as shown in Table 1, where Yb has a relatively small work function of 2.6 eV, which needs to satisfy LUMO. 第一有机材料 -work function 金属 If the energy level is ≤2.1 eV, then the LUMO energy level of the first organic material must satisfy the LUMO energy level. 第一有机材料≤4.7 eV. In the examples described herein, compounds 1-2 with a LUMO energy level less than 4.7 eV are preferred as the first organic material, with a LUMO energy level of 4.63 eV. The second organic material is preferably compound HT-7 with a HOMO energy level ≥5.1 eV, in which case the LUMO... 化合物1-2 -work function Yb =2.03eV, less than 2.1eV. By adjusting the work function of the metal material in the metal layer and the LUMO energy level difference of the first organic material in the first organic layer, the electron injection capability can be improved, thereby increasing the device efficiency. When HOMO... 第二有机材料 -LUMO 第一有机材料 At ≥0.3 eV, the hole injection level is regulated, allowing for better control of the injection level and achieving carrier balance, thereby improving exciton recombination efficiency. For example, in the device embodiment of this invention, the first organic material compound 1-2 is selected as a dopant and co-deposited with the second organic material compound HT-7 to form the second organic layer, and HOMO... HT-7 -LUMO 化合物1-2 =0.5eV, greater than 0.3eV, and with a doping concentration of 16wt%, superior device performance was obtained.

[0135] In this invention, compound PD-2 was selected as the connecting layer material for comparative examples, with a LUMO energy level of 4.91 eV and a HOMO energy level of [missing information]. HT-7 -LUMO 化合物PD-2 =0.22 eV. When the doping concentration of compound PD-2 is 3 wt%, although the low doping concentration ensures hole injection, the use of a deeper energy level first organic material results in a large difference between the LUMO of the first organic material and the work function of the metal (LUMO). HT-7 -work function Yb =2.31eV (greater than 2.1eV) is not conducive to electron separation and injection, hindering the improvement of device efficiency.

[0136] The applicant's previous application CN202110131806.4 discloses a multilayer organic electroluminescent device, which uses metallic Yb as the metal layer for charge generation, and compound 1-70. As a buffer layer (first organic layer) for charge generation, and with the LUMO level of compound 1-70 recorded as 5.69 eV, the LUMO in the stacked device disclosed in this application... 化合物1-70 -work function Yb =3.09eV, much greater than 2.1eV, which is different from the LUMO required in the technical solution claimed in this application. 第一有机材料 -work function 金属 ≤2.1eV is different and belongs to different inventive concepts.

[0137] The present invention will be described in more detail below with reference to the following embodiments. It is obvious that the following embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Based on the following embodiments, those skilled in the art can obtain other embodiments of the invention through modifications.

[0138] Device Examples

[0139] Example 1: Fabrication of a tandem organic electroluminescent device 100 comprising the connecting layer of the present invention, such as... Figure 1 As shown.

[0140] First, wash the pre-coated patterned area with ultrapure water. A glass substrate 110 with a thick indium tin oxide (ITO) anode 120 is used, and the ITO surface is treated with UV ozone and oxygen plasma. Afterwards, the substrate is dried in a nitrogen-filled glove box to remove moisture, then mounted on a support and placed in a vapor deposition chamber. The organic layer specified below is applied at a vacuum degree of approximately 1*10. -6 In the case of entrustment The deposition rate is achieved by sequentially depositing a film on the ITO anode via thermal evaporation. First, the first light-emitting unit 110a is deposited by evaporation, comprising compound HT-7 and compound 1-2 co-deposited to form a hole injection layer 111a, wherein compound 1-2 accounts for 16% of the weight of the hole injection layer (HIL) 111a, and the HIL layer thickness is [missing information]. The HT-7 compound was vapor-deposited as the hole transport layer (HTL) 112a, with a thickness of [missing information]. Evaporated compound H-1 was used as the electron blocking layer (EBL) 113a, with a thickness of Then, red dopant compound D-1 and red host compound H-2 were co-deposited to serve as the emissive layer (EML) 114a, with a doping concentration of 3 wt% and an EML layer thickness of [missing information]. On the light-emitting layer, a vapor-deposited compound H-3 serves as a hole-blocking layer (HBL) 115a, with a thickness of [missing information]. On the HBL, compounds ET and EI were co-deposited as an electron transport layer (ETL) 116a, with compound EI accounting for 60% of the total weight of the ETL layer. The thickness of the ETL layer was [missing information]. Then, the thicknesses are successively evaporated. Yb metal is used as the metal layer 130a of the connecting layer 130, and is deposited by vapor deposition. Compounds 1-2 are used as the first organic layer 130b of the connecting layer 130. Next, a second light-emitting unit 110b is deposited by vapor deposition, comprising a second organic layer (hole injection layer) 111b formed by co-depositing compound HT-7 and compound 1-2, wherein compound 1-2 accounts for 16% of the total weight of the second organic layer (hole injection layer 111b), and the HIL layer thickness is... Subsequently vapor deposition Compound HT-7 is used as the hole transport layer 112b. Compound H-1 is used as the electron blocking layer (EBL) 113b, with a thickness of [missing information]. Red dopant compound D-1 and red host compound H-2 were co-deposited as the emissive layer (EML) 114b, with a doping concentration of 3 wt% and a thickness of [missing information]. Compound H-3 was used as a hole blocking layer (HBL) 115b, which was deposited on top of the light-emitting layer with a thickness of [missing information]. On the HBL, compounds ET and EI were co-deposited as an electron transport layer (ETL) 116b, with compound EI accounting for 60% of the total weight of the ETL layer. The thickness of the ETL layer was [missing information]. Finally, vapor deposition A thick compound EI layer was used as the electron injection layer (EIL) 117b and was deposited by vapor deposition. Aluminum was used as the cathode 140.

[0141] Note that this device structure is merely an example and is not limited to the present invention. For example, the hole injection layer 111a in the first light-emitting unit 110a can use a different structure than the hole injection layer 111b in the second light-emitting unit 110b, and vice versa. As another example, the second light-emitting unit 110b can use host compounds and light-emitting materials of other colors, as well as corresponding matching transport materials and device structures. After the device is fabricated, it is transferred from the evaporation chamber back to the glove box and encapsulated with a glass cover.

[0142] Example 2: The preparation method is the same as in Example 1, except that: in the first light-emitting unit, compound HT-7 and compound 1-2 are co-deposited to form a hole injection layer (HIL, weight ratio 80:20). () to replace the hole injection layer of the first light-emitting unit in Embodiment 1.

[0143] Comparative Example 1: The preparation method is the same as in Example 1, except that: (1) in the first light-emitting unit, a hole injection layer (HIL, weight ratio 97:3) is formed by co-evaporation of compound HT-7 and compound PD-2. (1) Replace the hole injection layer of the first light-emitting unit in Example 1; (2) In the connecting layer, vapor deposit... Compound PD-2 forms a first organic layer to replace the first organic layer in the connecting layer in Example 1; (3) In the second light-emitting unit, compound HT-7 and compound PD-2 are co-deposited to form a hole injection layer (HIL, weight ratio 97:3). () to replace the hole injection layer of the second light-emitting unit in Example 1.

[0144] Comparative Example 2: The preparation method is the same as that of Comparative Example 1, except that: (1) in the first light-emitting unit, the hole injection layer (HIL) formed by co-evaporation of compound HT-7 and compound PD-2 has a weight ratio of 84:16 and a total thickness of (2) In the second light-emitting unit, a hole injection layer (HIL) formed by co-evaporation of compound HT-7 and compound PD-2 is used to replace the hole injection layer of the first light-emitting unit in Comparative Example 1; (3) In the second light-emitting unit, a hole injection layer (HIL) formed by co-evaporation of compound HT-7 and compound PD-2 is formed by a weight ratio of 84:16 and a total thickness of 100 mm. () to replace the hole injection layer of the second light-emitting unit in Comparative Example 1.

[0145] Comparative Example 3: The preparation method is the same as that of Example 1, except that: (1) in the bonding layer, vapor deposition is performed. (2) Compound PD-2 forms a first organic layer to replace the first organic layer in the connecting layer in Example 1; (3) In the second light-emitting unit, compound HT-7 and compound PD-2 are co-deposited to form a hole injection layer (HIL, weight ratio 84:16). () to replace the hole injection layer of the second light-emitting unit in Example 1.

[0146] Comparative Example 4: Fabrication of a red monolayer organic electroluminescent device 200, such as... Figure 2 As shown (this figure is for illustrative purposes only and does not include the base layer):

[0147] First, wash the pre-coated patterned area with ultrapure water. A thick indium tin oxide (ITO) anode 220 glass substrate was prepared, and the ITO surface was treated with UV ozone and oxygen plasma. Afterwards, the substrate was dried in a nitrogen-filled glove box to remove moisture, then mounted on a support and placed in a vapor deposition chamber. The organic layer specified below was applied under a vacuum of approximately 1*10⁻⁶. -6 In the case of entrustment The deposition rate was achieved by sequential thermal evaporation on the ITO anode 220. Compound HT-7 and compound 1-2 were co-deposited to form a hole injection layer (HIL) 211, wherein compound 1-2 accounted for 16% of the weight of the hole injection layer (HIL) 211, and the total thickness of the HIL was [missing information]. Compound HT-7 is used as the hole transport layer (HTL) 212, with a thickness of Compound H-1 is used as an electron blocking layer (EBL) 213 with a thickness of Then, red dopant compound D-1 and red host compound H-2 were co-deposited as the emissive layer (EML) 214, with a doping concentration of 3 wt% and a total thickness of [missing information]. Compound H-3 was used as a hole blocking layer (HBL) 215, which was deposited on the light-emitting layer with a thickness of [missing information]. On the HBL, compounds ET and EI were co-deposited as an electron transport layer (ETL) 216, with compound EI accounting for 60% of the total weight of the ETL layer. The total thickness of the ETL layer was [missing information]. Finally, vapor deposition The compound EI was used as the electron injection layer (EIL) 217 ​​and was deposited by vapor deposition. Aluminum is used as the cathode 230.

[0148] Comparative Example 5: A red monolayer organic electroluminescent device 300 was fabricated using the same method as Comparative Example 4 (monolayer device 200), except that: a hole injection layer was formed by co-depositing compound PD-2 and compound HT-7, wherein compound PD-2 accounted for 16% of the weight of the hole injection layer, and the thickness was [missing information].

[0149] Comparative Example 6: A red monolayer organic electroluminescent device 400 was fabricated using the same method as Comparative Example 5 (monolayer device 300), except that: a hole injection layer was formed by co-depositing compound PD-2 and compound HT-7, wherein compound PD-2 accounted for 3% of the weight of the hole injection layer, and the thickness was [missing information].

[0150] The detailed organic layer structure and thickness of the device are shown in Table 2 below. The layers use more than one material and are obtained by doping different compounds in the stated weight ratios.

[0151] Table 2. Partial device structures of Examples 1-2 and Comparative Examples 1-6

[0152]

[0153]

[0154] The structures of compounds 1-2, PD-2, HT-7, H-1, H-2, D-1, H-3, ET, and EI are shown below:

[0155]

[0156] Table 3 lists the performance test results of Examples 1-2 and Comparative Examples 1-6, where color coordinates, power efficiency, external quantum efficiency, and voltage are measured at a luminance of 2000 cd / m². 2 The measured device lifetime is when the device brightness decays to its initial brightness of 2000 cd / m². 2 97% of the time.

[0157] Table 3. Device performance of Examples 1-2 and Comparative Examples 1-6

[0158]

[0159]

[0160] The color coordinates of Examples 1-2 and Comparative Examples 1-6 are basically the same, indicating that the first organic material in the bonding layer does not affect the color of the device itself.

[0161] As shown in Table 3, the external quantum efficiency of Comparative Example 4 (single-layer device 200) is improved by 20% compared to Comparative Example 5 (single-layer device 300), but the voltage is also increased by 0.4V. Due to the increase in voltage, the external quantum efficiency of single-layer device 200 and single-layer device 300 is reduced to the same brightness of 2000 cd / m². 2 The power efficiency is the same, both at 17 lm / W. The difference between monolayer device 200 and monolayer device 300 lies in the doping material used in the hole injection layer. In monolayer device 200, the hole injection layer uses HOMO... HT-7 -LUMO 化合物1-2 =0.5eV, while the hole injection layer of the monolayer device 300 has a HOMO HT-7 -LUMO 化合物PD-2 =0.22eV. It can be seen that the large energy difference between compound HT-7 and compound 1-2 in the hole injection layer of monolayer device 200 makes hole injection difficult. Although its efficiency is 20% higher than that of monolayer device 300, the voltage is also increased and the device lifetime is slightly lower by 6%.

[0162] However, in the stacked device, a comparison of the device performance between Example 1 and Comparative Example 4 (single-layer device 200) shows that the external quantum efficiency of Example 1 is 2.3 times that of Comparative Example 4 (single-layer device 200), and the lifetime is 5.03 times that of single-layer device 200. However, the voltage in Example 1 is 6.3V, only 1.65 times that of device 200, and the power efficiency is also 45% higher than that of device 200. Therefore, although single-layer device 200 has a higher voltage compared to single-layer device 300, this phenomenon does not exist in the stacked device of Example 1. This indicates that the work function of the metal material in the connecting layer and the LUMO energy level difference of the first organic material have a significant impact on the voltage of the series device. The LUMO energy level difference in the connecting layer of Example 1 of this invention... 化合物1-2 -work function Yb =2.03eV, which indicates that the LUMO in the control series device interconnect layer 第一有机材料 Sum of work functions 金属 The energy level difference is less than 2.1 eV, preferably less than 2.05 eV, which can promote the separation of electrons at the metal-organic interface, thereby suppressing the recombination of charge carriers at the interface and thus improving the overall performance of the device.

[0163] Comparing Example 1 and Comparative Example 3, it can be seen that the metal layer in the connecting layer of Example 1 uses Yb, and the first organic layer uses compounds 1-2, LUMO. 化合物1-2 -work function Yb =2.03 eV; the second organic layer uses compounds HT-7 and 1-2, HOMO HT-7 -LUMO 化合物1-2 =0.5eV; while in Comparative Example 3, the metal layer of the connecting layer used Yb, and the first organic layer used compound PD-2, LUMO. 化合物PD-2 -work function Yb =2.31 eV, greater than 2.1 eV; the second organic layer uses compounds HT-7 and PD-2, HOMO HT-7 -LUMO 化合物PD-2 =0.22eV, less than 0.3eV. As shown in Table 3, compared to Comparative Example 3, Example 1 achieved a significant improvement of 21% in external quantum efficiency while maintaining a similar lifetime, and also improved power efficiency by 12%. This demonstrates that by controlling the energy difference between the HOMO level of the second organic material and the LUMO level of the first organic material in the hole injection layer (second organic layer) in contact with the connection layer, the HOMO... 第二有机材料 -LUMO 第一有机材料 At ≥0.3eV, hole injection in the device can be controlled; at the same time, the LUMO can be reduced. 第一有机材料 Sum of work functions 金属 The energy level difference makes the LUMO 第一有机材料属 -work function 金属 A voltage of ≤2.1eV can improve the electron injection capability of the device, thereby enhancing the overall performance of the series device, such as achieving higher external quantum efficiency and current efficiency.

[0164] Comparing the performance data of the multilayer device in Comparative Example 2 and Comparative Example 5 (single-layer device 300), it can be seen that the external quantum efficiency of Comparative Example 2 is 2.2 times that of Comparative Example 5 (single-layer device 300), its lifetime is 4.15 times that of the single-layer device 300, and its voltage is only 1.79 times that of the single-layer device 300. This indicates that the overall performance of the multilayer device in Comparative Example 2 has been significantly improved compared to the single-layer device 300.

[0165] Comparing the performance data of Comparative Example 5 (single-layer device 300) and Comparative Example 6 (single-layer device 400), it can be seen that compared with single-layer device 300, single-layer device 400 has a lower voltage and improved external quantum efficiency and power efficiency. This shows that when the doping concentration of compound PD-2 in the HIL layer is 3wt%, the overall performance of the device is superior. Based on this, we further optimized the stacked device of Comparative Example 2 to obtain Comparative Example 1, that is, the doping concentration of compound PD-2 in the HIL layer is 3wt%. As shown in Table 3, compared with Comparative Example 2, the device voltage of Comparative Example 1 remains at 6.1V, while the external quantum efficiency and lifetime are improved by 5% and 11%, respectively; and compared with Comparative Example 6 (single-layer device 400), the external quantum efficiency of Comparative Example 1 is 2.2 times that of single-layer device 400, the lifetime is 4.0 times that of Comparative Example 6, while the voltage is only 1.8 times that of Comparative Example 6. This indicates that Comparative Example 1 is already a stacked device with superior overall performance.

[0166] However, compared to Comparative Example 1, which had an optimized PD-2 doping ratio, Example 1 still achieved a 19% improvement in external quantum efficiency and a 13% improvement in power efficiency while maintaining essentially the same lifetime and voltage. Comparing the device structures of Example 1 and Comparative Example 1, it can be seen that Example 1 and Comparative Example 1 used compounds 1-2 and PD-2 as the first organic materials, respectively. In Example 1, the second organic layer contained HOMO... HT-7 -LUMO 化合物1-2 =0.5eV, greater than 0.3eV, in the connection layer, LUMO 化合物1-2 -work function Yb =2.03 eV, less than 2.1 eV; while in the second organic layer of Comparative Example 1, HOMO HT-7 -LUMO 化合物PD-2 =0.22eV, less than 0.3eV, LUMO in the linker layer 化合物PD-2 -work function Yb =2.31 eV, greater than 2.1 eV. This further proves the shrinking of LUMO. 第一有机材料 Sum of work functions 金属 The energy level difference makes LUMO 第一有机材料属 -work function 金属 ≤2.1eV, and control HOMO 第二有机材料 -LUMO 第一有机材料 At ≥0.3eV, the overall performance of the stacked device can be further improved, achieving higher external quantum efficiency and higher power efficiency.

[0167] In the stacked device disclosed in this application, the hole injection layer in contact with the anode and the hole injection layer (second organic layer) in contact with the connecting layer can have the same or different structures. For example, the doping materials and doping concentrations used in the hole injection layer of the first light-emitting unit and the hole injection layer (second organic layer) of the second light-emitting unit can be the same or different. However, the first organic layer in the connecting layer must use the same doping material as the second organic layer. For example, in Example 2, the doping concentration of compound 1-2 in the HIL of the first light-emitting unit is 20wt%, and the concentration of compound 1-2 in the second organic layer is 16%. That is, based on Example 1, Example 2 further increases the doping concentration of compound 1-2 in the HIL of the first light-emitting unit. While maintaining the same voltage, although the external quantum efficiency of Example 2 is reduced by 11%, it still reaches a relatively high level of 62%. In terms of lifetime, Example 2 further achieves a significant improvement of 35% compared to Example 1. It can be seen that by adjusting the hole injection in the HIL layer in contact with the anode, the carriers can be balanced, thereby balancing the device efficiency, lifetime, and voltage.

[0168] In summary, the tandem organic light-emitting device disclosed in this invention, comprising multiple light-emitting units, a second organic layer, and a specific connecting layer, satisfies LUMO. 第一有机材料 -work function 金属 ≤2.1eV can promote electron separation at the metal-organic interface, thereby suppressing carrier recombination at the interface; controlling HOMO 第二有机材料 -LUMO 第一有机材料 With a voltage ≥0.3V, by adjusting the doping concentration of the first organic material, hole injection is controlled, and carrier recombination in the light-emitting layer is balanced, thereby significantly improving the device's efficiency and lifetime while reducing power consumption. This novel tandem organic electroluminescent device exhibits superior device performance and broader application prospects.

[0169] It should be understood that the various embodiments described herein are merely examples and are not intended to limit the scope of the invention. Therefore, as will be apparent to those skilled in the art, the claimed invention may include variations of the specific embodiments and preferred embodiments described herein. Many of the materials and structures described herein can be substituted with other materials and structures without departing from the spirit of the invention. It should be understood that various theories regarding why the invention works are not intended to be limiting.

Claims

1. An organic electroluminescent device, comprising: First electrode, Second electrode, and at least two light-emitting units disposed between the first electrode and the second electrode. A connecting layer is further disposed between the at least two light-emitting units. The connecting layer comprises a metal layer and a first organic layer. The first organic layer comprises a first organic material, and the LUMO energy level of the first organic material is LUMO. 第一有机材料 The metal layer comprises at least one metallic material, and the work function of the metallic material is a work function. 金属 The LUMO 第一有机材料 -work function 金属 ≤2.1eV; the LUMO energy level of the first organic material is ≤4.7eV; The light-emitting unit in contact with the first organic layer further comprises a second organic layer, and the second organic layer comprises a second organic material and the first organic material; the HOMO energy level of the second organic material is HOMO. 第二有机材料 And HOMO 第二有机材料 -LUMO 第一有机材料 ≥0.3eV.

2. The organic electroluminescent device as described in claim 1, wherein, The first organic material has a structure represented by one of Formulas 1 to 3: In Equation 1, Equation 2 or Equation 3 E is selected from CR1 each time it appears, either identically or differently; Each time X appears, it is selected from the group consisting of NR', CR”R”', O, S and Se, either the same or different. Each time ring A appears, it is either the same or different five-membered heterocycle, and the five-membered heterocycle contains an intracyclic double bond, at least one N atom and at least one Q atom; Q is chosen freely from O, S, Se, and NR each time it appears, either the same or different. N The group formed; The same or different occurrences of R each indicate monosubstitution, polysubstitution, or no substitution; R, R1, R', R", R"', R N Each time it appears, it is selected from the group consisting of the following groups, either identically or differently: hydrogen, deuterium, halogen, nitrosyl, nitro, acyl, carbonyl, carboxylic acid, ester, cyano, isocyanate, SCN, OCN, SF5, borane, sulfinyl, sulfonyl, phosphooxy, hydroxyl, mercapto, substituted or unsubstituted alkyl groups having 1-20 carbon atoms, substituted or unsubstituted cycloalkyl groups having 3-20 ring carbon atoms, substituted or unsubstituted heteroalkyl groups having 1-20 carbon atoms, substituted or unsubstituted heterocyclic groups having 3-20 ring atoms, substituted or unsubstituted aralkyl groups having 7-30 carbon atoms, substituted or unsubstituted groups having 1-20 carbon atoms. Alkoxy groups with 6 to 30 carbon atoms, substituted or unsubstituted aryloxy groups with 2 to 20 carbon atoms, substituted or unsubstituted alkynyl groups with 2 to 20 carbon atoms, substituted or unsubstituted aryl groups with 6 to 30 carbon atoms, substituted or unsubstituted heteroaryl groups with 3 to 30 carbon atoms, substituted or unsubstituted alksilyl groups with 3 to 20 carbon atoms, substituted or unsubstituted arylsilyl groups with 6 to 20 carbon atoms, substituted or unsubstituted alkylgermanium groups with 3 to 20 carbon atoms, substituted or unsubstituted arylgermanium groups with 6 to 20 carbon atoms, and combinations thereof; Furthermore, at least one of the substituents R, R1, R', R” and R”' is a group having at least one electron-withdrawing group; Adjacent substituents R, R', R", R"' can optionally connect to form a ring.

3. The organic electroluminescent device as claimed in claim 2, wherein the first organic material has a structure represented by formula 1 or formula 2.

4. The organic electroluminescent device as described in claim 2, wherein, Each time X appears, it is selected from CR”R”' or NR’, and each of R’, R” and R”' is a group having at least one electron-withdrawing group.

5. The organic electroluminescent device of claim 2, wherein each of R, R', R” and R”' is a group having at least one electron-withdrawing group.

6. The organic electroluminescent device according to any one of claims 2-5, wherein, Each time X appears, it is selected from the group consisting of the following structures, either identically or differently:

7. The organic electroluminescent device of claim 6, wherein X is selected from X-1.

8. The organic electroluminescent device according to any one of claims 1-5, wherein, The first organic material is selected from the group consisting of the following structures:

9. The organic electroluminescent device as claimed in claim 1, wherein, The metal material in the metal layer is selected from the group consisting of: Yb, Li, Rb, Cs, Be, Mg, Ca, Sr, Ba, La, Ce, Pr, Nd, Sm, Eu, Y, Mn, Ag, and combinations of multiple metals above.

10. The organic electroluminescent device as claimed in claim 1, wherein the metal material in the metal layer is Yb.

11. The organic electroluminescent device as claimed in claim 1 or 9, wherein, The work function of the metal material in the metal layer is less than 4.0 eV.

12. The organic electroluminescent device as claimed in claim 1, wherein, The metal layer is formed from one elemental metal or from two or more elemental metals.

13. The organic electroluminescent device as claimed in claim 1, wherein, The thickness of the metal layer is between 0.1 nm and 20 nm.

14. The organic electroluminescent device of claim 1, wherein the thickness of the metal layer is between 0.1 nm and 5 nm.

15. The organic electroluminescent device according to any one of claims 1-5, wherein, The LUMO 第一有机材料 -work function 金属 <2.05eV.

16. The organic electroluminescent device as claimed in claim 1, wherein, The thickness of the first organic layer is between 0.1 nm and 30 nm.

17. The organic electroluminescent device of claim 1, wherein the thickness of the first organic layer is between 0.1 nm and 15 nm.

18. The organic electroluminescent device as claimed in claim 1, wherein, In the second organic layer, the first organic material accounts for 4% to 49% of the total mass of the second organic layer.

19. The organic electroluminescent device as claimed in claim 1, wherein in the second organic layer, the first organic material accounts for 5% to 35% of the total mass of the second organic layer.

20. The organic electroluminescent device as claimed in claim 1, wherein in the second organic layer, the first organic material accounts for 5% to 30% of the total mass of the second organic layer.

21. The organic electroluminescent device as claimed in claim 1, wherein, At least one of the first organic layer and the metal layer forms a discontinuous thin film.

22. The organic electroluminescent device as claimed in claim 1, wherein, The first organic layer is in direct contact with the second organic layer.

23. The organic electroluminescent device as claimed in claim 1, wherein, The HOMO 第二有机材料 -LUMO 第一有机材料 ≤0.8eV.

24. The organic electroluminescent device as claimed in claim 1, wherein the HOMO 第二有机材料 -LUMO 第一有机材料 ≤0.6eV.

25. The organic electroluminescent device as claimed in claim 1, wherein, The HOMO energy level of the second organic material is ≥5.1 eV.

26. The organic electroluminescent device as claimed in claim 1, wherein, The bonding layer has a transmittance of more than 70% in the visible light range.

27. The organic electroluminescent device of claim 1, wherein the transmittance of the connecting layer in the visible light range is greater than 80%.

28. The organic electroluminescent device as claimed in claim 1, wherein, The at least two light-emitting units can emit light of the same color or different colors.

29. An electronic component comprising the organic electroluminescent device according to any one of claims 1-28.

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