Light emitting device and display device

Abstract

The present invention provides a light-emitting device and a display device, belonging to the field of display technology. The light-emitting device of the present invention comprises a substrate, a first electrode, a functional layer, and a second electrode arranged on the substrate in sequence; the functional layer at least comprises a light-emitting layer; a dielectric layer is arranged between at least one of the first electrode and the second electrode and the functional layer, and metal nanoparticles are arranged in the dielectric layer; the local plasma resonance frequency of the metal nanoparticles matches the light-emitting wavelength of the light-emitting layer; the material of the dielectric layer adopts a polymer containing polyoxymethylene.

Description

Technical Field

[0001] The present invention belongs to the field of display technology, and in particular relates to a light-emitting device and a display apparatus. Background Art

[0002] OLED (Organic Light-Emitting Device, OLED for short) is a light-emitting device that uses organic solid-state semiconductors as light-emitting materials. It has broad application prospects due to its advantages such as simple preparation process, low cost, low power consumption, high luminous brightness, and wide operating temperature adaptability. However, since the preparation process of OLED devices mainly relies on evaporation, there are certain difficulties in high-precision display, and the utilization rate of materials is low. In recent years, quantum dot materials have gradually emerged. Their luminous spectrum is narrower than that of organic materials, and their stability is better than that of organic materials. Therefore, QLED (Quantum Dot Light Emitting Diodes, QLED for short) was born and is widely used in the display field. Summary of the invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art and provide a light emitting device and a display apparatus.

[0004] In a first aspect, an embodiment of the present disclosure provides a light-emitting device, which includes a substrate, a first electrode, a functional layer, and a second electrode sequentially arranged on the substrate; the functional layer includes at least a light-emitting layer;

[0005] A dielectric layer is disposed between at least one of the first electrode and the second electrode and the functional layer, and metal nanoparticles are disposed in the dielectric layer;

[0006] The local plasma resonance frequency of the metal nanoparticles matches the luminous wavelength of the luminous layer; the material of the dielectric layer adopts a polymer containing polyoxymethylene.

[0007] Optionally, the dielectric layer is a single-layer structure, and the metal nanoparticles include metal nanoparticles of two different sizes.

[0008] Optionally, the dielectric layer includes a first sub-dielectric layer and a second sub-dielectric layer stacked in a direction away from the light-emitting layer; the metal nanoparticles are arranged in both the first sub-dielectric layer and the second sub-dielectric layer, and the size of the metal nanoparticles arranged in the second sub-dielectric layer is larger than the size of the metal nanoparticles arranged in the first sub-dielectric layer.

[0009] Optionally, the first electrode is an anode and the second electrode is a cathode; the functional layer also includes a hole injection layer and a hole transport layer located between the substrate and the light-emitting layer and arranged in sequence along a direction away from the substrate; the dielectric layer is located between the anode and the hole injection layer.

[0010] Optionally, the first electrode is a cathode, and the second electrode is an anode; the functional layer further includes an electron transport layer located between the substrate and the light-emitting layer; and the dielectric layer is located between the cathode and the electron transport layer.

[0011] Optionally, the first electrode is a cathode, and the second electrode is an anode; the functional layer further includes an electron injection layer and an electron transport layer located between the substrate and the light-emitting layer and arranged in sequence along a direction away from the substrate; the dielectric layer is located between the cathode and the electron injection layer.

[0012] Optionally, one of the anode and the cathode is a transparent electrode, and the other is a reflective electrode.

[0013] Optionally, the size of the metal nanoparticles is 5nm-450nm.

[0014] Optionally, the metal nanoparticle material includes any one or more of gold, silver, and platinum.

[0015] Optionally, the material of the dielectric layer includes polyoxymethylene.

[0016] Optionally, the light emitting device includes an organic light emitting diode or a quantum dot light emitting diode.

[0017] In a second aspect, an embodiment of the present disclosure provides a display device, which includes the above-mentioned light-emitting device. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of a light emitting device according to an embodiment of the present disclosure;

[0019] Figure 2 is a schematic structural diagram of another light emitting device according to an embodiment of the present disclosure;

[0020] Figure 3 is a schematic structural diagram of another light emitting device according to an embodiment of the present disclosure;

[0021] Figure 4 A schematic diagram of a dielectric layer of a light-emitting device according to an embodiment of the present disclosure;

[0022] Figure 5 is a schematic diagram of another dielectric layer of the light-emitting device according to an embodiment of the present disclosure;

[0023] Figure 6It is a structural schematic diagram of a normal light emitting device according to an embodiment of the present disclosure;

[0024] Figure 7 It is a structural schematic diagram of an inverted light-emitting device according to an embodiment of the present disclosure;

[0025] Figure 8 It is a schematic structural diagram of another inverted light-emitting device according to an embodiment of the present disclosure.

[0026] The figures are marked as follows: 10, substrate; 1, first electrode; 11, anode; 2, second electrode; 21, cathode; 3, functional layer; 31, light-emitting layer; 32, hole transport layer; 33, hole injection layer; 34, electron transport layer; 35, electron injection layer; 4, metal nanoparticles; 5, dielectric layer; 51, first sub-dielectric layer; 52, second sub-dielectric layer. DETAILED DESCRIPTION

[0027] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0028] Unless otherwise defined, the technical terms or scientific terms used in the present disclosure should be understood by people with ordinary skills in the field to which the present disclosure belongs. The "first", "second" and similar words used in the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, similar words such as "one", "one" or "the" do not indicate quantity restrictions, but indicate that there is at least one. Similar words such as "include" or "comprise" mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Similar words such as "connect" or "connected" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0029] The basic structure of a light-emitting device includes: an anode, a cathode, and a light-emitting layer between the anode and the cathode. Under the action of an external voltage, electrons and holes are injected from the cathode and anode directions respectively, then migrate and meet and recombine in the light-emitting layer to produce excitons. The energy of the excitons decays in the form of light, that is, radiates light. Among them, the light extraction efficiency of a light-emitting device is one of the indicators to measure the performance of a light-emitting device.

[0030] At present, two methods are usually used to improve the light extraction efficiency: one method is to improve the internal quantum efficiency, and the other method is to improve the external quantum efficiency. Among them, when photons are incident on the surface of the photosensitive device, some photons are absorbed and excite the photosensitive material to generate electron-hole pairs, forming a current. The ratio of the number of electrons generated to the number of absorbed photons is the internal quantum efficiency; and the ratio of the number of electrons generated to all incident photons is the external quantum efficiency. The internal quantum efficiency mainly measures the proportion of the excitons generated by the recombination of injected carriers in the light-emitting layer that are converted into photon-coupled luminescence to the total number of excitons. Taking OLED as an example, improving the internal quantum efficiency can be achieved by improving material properties or using phosphorescent materials, and theoretically, an internal quantum efficiency of nearly 100% can be achieved. Improving the external quantum efficiency means improving the coupling light extraction efficiency of OLED. For planar light-emitting devices, usually only about 20% of the photons emitted by excitons can be extracted, and most (80%) of the energy is lost in multiple modes, such as: substrate mode occurring at the refractive or reflective interface between the anode and substrate, substrate and air of OLED, waveguide mode occurring between the anode and the light-emitting layer interface of OLED, and surface plasma (SP) mode occurring near the metal electrode. Among them, more than 40% of the light is confined in the OLED due to the SP mode, and the light confined by the waveguide mode and substrate mode accounts for 15% and 23% respectively. The loss caused by metal absorption is 4%, resulting in only about 20% of the light emitted from the light-emitting layer being able to pass through the OLED into the air and be seen by the human eye.

[0031] In order to improve the light extraction efficiency of the light-emitting device, the inventors formed a layer of metal nanoparticles between the light-emitting layer and the anode and / or between the light-emitting layer and the cathode. The localized surface plasma resonance frequency of the metal nanoparticles matches the light emission wavelength of the light-emitting layer to improve the light extraction efficiency of the light-emitting device.

[0032] Specifically, surface plasmon (SP) refers to an electron density wave that propagates along the metal surface when the freely vibrating electrons on the metal surface are excited by electrons or light waves and interact with electrons or photons. It is an electromagnetic surface wave that can laterally confine light waves to a sub-wavelength scale, and its dispersion curve is flat near the resonant frequency, the photon state density is large, and its spontaneous radiation can be enhanced when interacting with the surrounding medium. The field intensity of this electron density wave is the largest at the surface, and it is an exponentially decaying field in the direction perpendicular to the interface. If the metal surface is very rough or near the curved surface structure of the metal (such as a sphere, cylinder, etc.), the surface plasmon cannot propagate along the interface in the form of a wave, but is localized near the surface of these structures, that is, the localization of the surface plasmon. At this time, the surface plasmon SP is called localized surface plasmon (LSP). When metal particles whose size is close to or smaller than the wavelength of light are illuminated by light, their oscillating electric field causes the electron cloud of the metal particles to shift relative to the nucleus. The Coulomb attraction between the electron cloud and the nucleus generates a restoring force, causing the electron cloud to oscillate around the nucleus. This collective oscillation of the electron cloud is called localized surface plasmon resonance.

[0033] When localized surface plasmon resonance occurs, the electromagnetic field around the metal particle is greatly enhanced. At this time, the metal particle can be regarded as a nanolens, and the oscillating plasma is a photon, which is strongly confined within a nanometer-sized particle. A significant effect of localized surface plasmon resonance is that the surface plasmon generates radiation consistent with the wavelength of the fluorescent molecule under the fluorescence induction of the excitation photon (such as the luminescent photon of the luminescent layer), while increasing the radiation decay rate of the system, reducing the fluorescence lifetime of the photon, increasing the fluorescence quantum efficiency, and enhancing the fluorescence emission.

[0034] It should be noted that the above description is based on the example of OLED as the light-emitting device. The only difference between QLED and OLED is the material of the light-emitting layer, and the light-emitting principles are roughly the same.

[0035] In summary, although adding metal nanoparticles to the light-emitting device and utilizing the principle of localized surface plasmon resonance can improve the light extraction efficiency of the light-emitting device, the inventors have found that when oxygen infiltrates the light-emitting device, the oxygen will damage the light-emitting device, resulting in a reduction in the life of the light-emitting device. To address this problem, the following technical solutions are provided in the embodiments of the present disclosure.

[0036] First, as Figure 1-3As shown, the embodiment of the present disclosure provides a light-emitting device, which includes a substrate 10, a first electrode 1, a functional layer 3, and a second electrode 2 arranged in sequence in a direction away from the substrate 10; wherein one of the first electrode 1 and the second electrode 2 is an anode 11, and the other is a cathode 21; the functional layer 3 at least includes a light-emitting layer 31. In particular, a dielectric layer 5 is arranged between the first electrode 1 and the functional layer 3 of the light-emitting device, and metal nanoparticles 4 are arranged in the dielectric layer 5, and / or a dielectric layer 5 is arranged between the second electrode 2 and the functional layer 3 of the light-emitting device, and metal nanoparticles 4 are arranged in the dielectric layer 5. The localized surface plasmon resonance frequency of the metal nanoparticles 4 matches the light-emitting wavelength of the light-emitting layer 31, and the material of the dielectric layer 5 adopts a polymer containing polyoxymethylene (POM).

[0037] It should be noted here that the matching of the localized surface plasmon resonance frequency of the metal nanoparticles 4 with the emission wavelength of the light-emitting layer 31 means that the size of the metal nanoparticles 4 is close to or smaller than the emission wavelength of the light-emitting layer 31, so that when the metal nanoparticles 4 are illuminated, their oscillating electric field causes the electron cloud of the metal nanoparticles 4 to shift relative to the nucleus, and the Coulomb attraction between the electron cloud and the nucleus generates a restoring force, causing the electron cloud to oscillate around the nucleus, i.e., localized surface plasmon resonance occurs.

[0038] Polyoxymethylene (POM) is an engineering plastic with excellent performance, known as "steel" and "super steel" abroad. Polyoxymethylene has the hardness, strength and rigidity similar to metals, and has good self-lubrication, good fatigue resistance and elasticity in a wide range of temperature and humidity. In addition, it has good chemical resistance. With a lower cost than many other engineering plastics, POM is replacing some markets traditionally occupied by metals, such as replacing zinc, brass, aluminum and steel to make many parts. Since its introduction, polyoxymethylene has been widely used in the fields of electronics, machinery, instrumentation, daily light industry, automobiles, building materials, agriculture, etc.

[0039] In some embodiments, the material of the dielectric layer 5 may be polyoxymethylene or a copolymer containing polyoxymethylene.

[0040] In some embodiments, the material forming the metal nanoparticles 4 is usually an inert precious metal, such as any one of gold (Au), silver (Ag), platinum (Pt), aluminum (Al), or an alloy of gold, silver, platinum, and aluminum, or any combination of gold, silver, platinum, and aluminum; the metal nanoparticles 4 are in the form of spheres, prisms, cubes, cages, core-shell structures, or any combination thereof. According to the wavelength of light emitted by light-emitting devices of different luminous colors (red / green / blue), the size of the metal nanoparticles 4 required for LSP generation is about 5nm-450nm, and the preferred size is about 5nm-100nm.

[0041] In the light-emitting device of the present disclosure, metal nanoparticles 4 whose local surface plasmon resonance frequency matches the light-emitting wavelength of the light-emitting layer 31 are arranged to improve the light extraction efficiency of the light-emitting device. The principle is the same as that described above and will not be repeated here. In particular, a dielectric layer 5 of a polymer material containing polyformaldehyde is formed between the electrode (the first electrode 1 and / or the second electrode 2) of the light-emitting device and the functional layer 3. The polyformaldehyde can release formaldehyde very slowly. The formaldehyde can react with oxygen under the catalytic action of the metal nanoparticles 4 and be converted into formic acid, thereby preventing oxygen from damaging the light-emitting device itself.

[0042] In some embodiments, the substrate 10 is used as the support of the electrode layer and the functional layer in the light-emitting device. It has good light transmittance in the visible light region and a certain ability to resist water vapor and oxygen penetration, and has good surface flatness. It can generally be made of glass, a flexible substrate, or an array substrate, etc. If a flexible substrate is selected, it can be made of polyester, polyphthalimide or a thinner metal.

[0043] In some embodiments, the dielectric layer 5 of the light-emitting device is only disposed between the first electrode 1 and the functional layer 3, that is, the dielectric layer 5 is formed first and then the functional layer 3 is formed, so that the performance of the functional layer 3 can be effectively avoided from being affected when the dielectric layer 5 is formed. Of course, it is also feasible to dispose the dielectric layer 5 between the second electrode 2 and the functional layer 3. For the convenience of description, the following description takes the dielectric layer 5 disposed between the first electrode 1 and the functional layer 3 as an example.

[0044] Among them, since the dielectric layer 5 is arranged between the first electrode 1 and the functional layer 3, wherein the functional layer 3 generally includes not only the light-emitting layer 31, but also includes a carrier transport layer arranged between the light-emitting layer 31 of the first electrode 1, wherein if the first electrode 1 is an anode 11, the carrier transport layer is a hole transport layer 32, and if the first electrode 1 is a cathode 21, the carrier transport layer is an electron transport layer 34. Therefore, the size of the metal nanoparticles 4 in the dielectric layer 5 is to ensure that the LSP can be achieved while ensuring that the dielectric layer 5 can electrically connect the first electrode 1 and the carrier transport layer well. In this regard, the following two implementation methods are provided in the embodiments of the present disclosure.

[0045] In one example, if Figure 4As shown, the dielectric layer 5 adopts a single-layer structure, and the metal nanoparticles 4 include metal nanoparticles 4 of two different sizes, wherein the small-sized metal nanoparticles 4 of the two different sizes have good LSP characteristics, and the large-sized metal nanoparticles have good electrical conductivity. Of course, only one size of metal nanoparticles 4 can be set in the dielectric layer 5, and the metal nanoparticles 4 can generate LSP. Among them, the size of the small-sized metal nanoparticles 4 is about 2nm-300nm, and the size of the large-sized metal nanoparticles 4 is about 50nm-5000nm. For both the large-sized and small-sized metal nanoparticles 4, when forming the dielectric layer, the large-sized and small-sized metal nanoparticles 4 can be physically mixed in the dielectric layer 5 so that the dielectric layer 5 includes the large-sized and small-sized metal nanoparticles 4.

[0046] In another example, Figure 5 As shown, the dielectric layer 5 adopts a double-layer structure, that is, the dielectric layer 5 includes a first sub-dielectric layer 51 and a second sub-dielectric layer 52 stacked; wherein the first sub-dielectric layer 51 and the second sub-dielectric layer 52 are sequentially arranged in a direction away from the light-emitting layer 31. The metal nanoparticles 4 are arranged in both the first sub-dielectric layer 51 and the second sub-dielectric layer 52, and the size of the metal nanoparticles 4 arranged in the second sub-dielectric layer 52 is larger than the size of the metal nanoparticles 4 arranged in the first sub-dielectric layer 51. Thus, the small-sized metal nanoparticles 4 in the first sub-dielectric layer 51 can generate LSP, and the second sub-dielectric layer 52 has good conductivity through the large-sized metal nanoparticles 4. Among them, the size range of the small-sized and large-sized metal nanoparticles 4 can be the same as the range in the first example, and the mixing method of the small-sized and large-sized metal nanoparticles 4 with the first sub-dielectric layer 51 and the second sub-dielectric layer 52 can be the same as the mixing method of the large-sized and small-sized metal nanoparticles 4 in the dielectric layer 5 in the first example, so it will not be repeated here.

[0047] In the embodiment of the present disclosure, the light emitting device may be an OLED or a QLED.

[0048] When the light emitting device is an OLED, the material of the light emitting layer 31 can be made of the following materials:

[0049] (1) It is made of undoped fluorescent organic material (composed of a light-emitting material with hole transport capability), and the light-emitting material with hole transport capability can be NPB or DPVBI, etc.

[0050] (2) It is made of an organic material doped with a fluorescent material (composed of a fluorescent dopant and a matrix material), wherein the fluorescent dopant can be coumarin dye (coumarin 6, C-545T), quinacridone (DMQA), or DCM series, etc.

[0051] (3) It is made of organic materials doped with phosphorescent materials (composed of phosphorescent dopants and matrix materials), and the phosphorescent dopant can be a luminescent material based on metal complexes such as Ir, Pt, Ru, Cu, etc., such as: FIrpic, Fir6, FirN4, FIrtaz, Ir(ppy)3, Ir(ppy)2(acac), PtOEP, (btp)2Iracac, Ir(piq)2(acac), or (MDQ)2Iracac, etc.

[0052] Among them, the matrix materials in the organic materials doped with fluorescent materials and the organic materials doped with phosphorescent materials can be: metal complex materials, anthracene derivatives, aromatic diamine compounds, triphenylamine compounds, aromatic triamine compounds, benzenediamine derivatives, or triarylamine polymers, etc., specifically: bis(2-methyl-8-hydroxyquinoline)(p-phenylphenol)aluminum (Balq), 9,10-di-(2-naphthyl)anthracene (ADN), TAZ, CBP, MCP, TCTA, or NPB, etc.

[0053] When the light emitting device is a QLED, the material of the light emitting layer 31 can be made of the following materials:

[0054] The material of the light-emitting layer 31 is a quantum dot material, examples of which include CdS / ZnS, CdSe / ZnS, CdSe / ZnSeS, CdSe / CdS, ZnSe / ZnS, InP / ZnS, CuInS / ZnS, (Zn)CuInS / ZnS, (Mn)CuInS / ZnS, AgInS / ZnS, (Zn)AgInS / ZnS, CuInSe / ZnS, CuInSeS / ZnS, PbS / ZnS, organic-inorganic perovskite materials, and inorganic perovskite materials.

[0055] Among them, examples of organic-inorganic perovskite materials include MAPbX3, where MA represents CH3NH3 and X represents a halide. Examples of inorganic perovskite materials include CsSb2Br9, CsBi2Br9, CsPbX3, where X represents a halide. Optionally, the quantum dot includes a core and a shell covering the core. Optionally, the core includes a material selected from the group consisting of CdS, CdSe, ZnSe, InP, CuInS, (Zn)CuInS, (Mn)CuInS, AgInS, (Zn)AgInS, CuInSe, CuInSeS, PbS, organic-inorganic perovskite materials, inorganic perovskite materials, and any combination or alloy thereof. Optionally, the shell includes a material selected from the group consisting of ZnS, ZnSeS, CdS, organic-inorganic perovskite materials, inorganic perovskite materials, and any combination or alloy thereof.

[0056] In the embodiments of the present disclosure, the light-emitting device may be a normal light-emitting device or an inverted light-emitting device. The first electrode 1 of the normal light-emitting device is an anode 11, and the second electrode 2 is a cathode 21; the first electrode 1 of the inverted light-emitting device is a cathode 21, and the second electrode 2 is an anode 11. Regardless of whether the light-emitting device is a normal light-emitting device or an inverted light-emitting device, the light-emitting device may be a top-emitting light-emitting device or a bottom-emitting light-emitting device; when the light-emitting device is a top-emitting light-emitting device, the first electrode 1 is a reflective electrode, and the second electrode 2 is a transmissive electrode; when the light-emitting device is a bottom-emitting light-emitting device, the first electrode 1 is a transmissive electrode, and the second electrode 2 is a reflective electrode. The specific structure of the light-emitting device is described below according to the type of the light-emitting device.

[0057] The first example is Figure 6 As shown, the light-emitting device is a positive light-emitting device, the first electrode 1 is the anode 11; the second electrode 2 is the cathode 21; the functional layer 3 includes a hole injection layer 33 (Hole Injection Layer, HIL for short), a hole transport layer 32 (Hole Transport Layer, HIL for short), a light-emitting layer 31, and an electron transport layer 34 (Electron Transport Layer, ETL for short) arranged in sequence away from the first electrode 1. Of course, an electron injection layer 35 (Electron Injection Layer, EIL for short) can also be arranged between the electron transport layer 34 and the cathode 21. The dielectric layer 5 is arranged between the hole injection layer 33 and the anode 11, and metal nanoparticles 4 are arranged in the dielectric layer 5. The material of the light-emitting layer 31 can be any one of the above materials.

[0058] Among them, the anode 11 includes but is not limited to a flexible electrode, and its material includes but is not limited to a high work function metal material (such as gold, copper, silver, platinum, etc.) or an inorganic metal oxide (such as indium tin oxide ITO, zinc oxide ZnO, etc.), an organic conductive polymer (such as poly (3,4-ethylenedioxythiophene) / polystyrene sulfonate PEDOT: PSS, polyaniline PANI, etc.).

[0059] The cathode 21 includes but is not limited to a flexible electrode, and its material includes but is not limited to a low work function metal material, such as lithium, magnesium, calcium, strontium, aluminum, indium, etc., or alloys of the above metals with copper, gold, and silver; or a very thin buffer insulating layer (such as LiF, CsCO3, etc.) and the above metals or alloys.

[0060] The material of the hole injection layer 33 includes, but is not limited to, poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), polythiophene, polyaniline, polypyrrole, copper phthalocyanine and 4,4,4"-tris(N,N-phenyl-3-methylphenylamino)triphenylamine (m-MTDATA), MoO3, CuPc, poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS).

[0061] The material of the hole transport layer 32 includes, but is not limited to, p-type polymer materials and various p-type low molecular weight materials, for example, polythiophene, polyaniline, polypyrrole, and a mixture of poly-3,4-ethylenedioxythiophene and poly(sodium p-styrenesulfonate), 4,4'-cyclohexylenebis[N,N-bis(4-methylphenyl)aniline (TAPC), 4,4',4"-tri(N-carbazolyl)triphenylamine (TCTA), N,N'-di(1-naphthyl)-N,N'-diphenylbenzidine (NPB), or any combination thereof.

[0062] The material of the electron transport layer 34 includes, but is not limited to, zinc oxide, magnesium zinc oxide, aluminum zinc oxide, and magnesium aluminum zinc oxide.

[0063] The material of the electron injection layer 35 includes, but is not limited to, any one of lithium fluoride, sodium fluoride, potassium fluoride, rubidium fluoride, cesium fluoride, lithium oxide, and lithium metaborate.

[0064] For the above-mentioned upright light-emitting device, the light-emitting device can be a top-emitting light-emitting device or a bottom-emitting light-emitting device. When the upright light-emitting device is a top-emitting device, the anode 11 is a reflective electrode and the cathode 21 is a transmissive electrode; at this time, the anode 11 can be made of a composite film layer formed by, for example, ITO / Ag / ITO materials (Ag film layer is used as a reflective layer); the cathode 21 can be made of a composite film layer formed by Mg:Ag / ITO materials, but at this time, the film thickness of the cathode 21 should ensure that the cathode 21 can transmit light. When the upright light-emitting device is a bottom-emitting device, the anode 11 can be made of transparent conductive materials such as indium tin oxide ITO and zinc oxide ZnO, and the cathode 21 can be made of Al material.

[0065] The second example, such as Figure 7 and 8 As shown, the light emitting device is an inverted light emitting device, the first electrode 1 is a cathode 21; the second electrode 2 is an anode 11; the functional layer 3 includes an electron transport layer 34, a light emitting layer 31, a hole transport layer 32, and a hole injection layer 33 arranged in sequence along the back. Of course, an electron injection layer 35 (Electron Injection Layer, referred to as EIL) can also be arranged between the electron transport layer 34 and the cathode 21. Figure 7As shown, when the electron injection layer 35 is not provided in the light emitting device, the dielectric layer 5 is provided between the electron transport layer 34 and the cathode 21, and the dielectric layer 5 is provided with metal nanoparticles 4; Figure 8 As shown, when an electron injection layer 35 is provided in the light-emitting device, a dielectric layer 5 is provided between the electron injection layer 35 and the cathode 21, and metal nanoparticles 4 are provided in the dielectric layer 5. The material of the light-emitting layer 31 can be any one of the above materials. The electron injection layer 35, the electron transport layer 34, the hole transport layer 32, and the hole injection layer 33 can all be made of the same materials as above.

[0066] Similarly, when the inverted light-emitting device is top-emitting, the anode 11 is a reflective electrode and the cathode 21 is a transmissive electrode; at this time, the anode 11 can be made of a composite film layer formed by, for example, ITO / Ag / ITO materials (Ag film layer is used as a reflective layer); the cathode 21 can be made of a composite film layer formed by Mg:Ag / ITO materials, but at this time, the film thickness of the cathode 21 should ensure that the cathode 21 can transmit light. When the inverted light-emitting device is bottom-emitting, the anode 11 can be made of transparent conductive materials such as indium tin oxide ITO and zinc oxide ZnO, and the cathode 21 can be made of Al materials.

[0067] In a second aspect, an embodiment of the present disclosure provides a display device, which includes any one of the above-mentioned light-emitting devices, so the display device of this embodiment has good light-emitting efficiency and service life.

[0068] The display device can be: electronic paper, OLED panel, QLED panel, mobile phone, tablet computer, television, monitor, notebook computer, digital photo frame, navigator, or any other product or component with display function.

[0069] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, but the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A light-emitting device, comprising a substrate, a first electrode, a functional layer, and a second electrode sequentially arranged on the substrate; the functional layer at least comprises a light-emitting layer; characterized in that: A dielectric layer is disposed between at least one of the first electrode and the second electrode and the functional layer, the dielectric layer is in contact with the functional layer, and metal nanoparticles are disposed in the dielectric layer; The local plasma resonance frequency of the metal nanoparticles matches the luminescent wavelength of the luminescent layer; the material of the dielectric layer is a polymer containing polyoxymethylene; The dielectric layer includes a first sub-dielectric layer and a second sub-dielectric layer stacked in a direction away from the light-emitting layer; the metal nanoparticles are arranged in both the first sub-dielectric layer and the second sub-dielectric layer, and the size of the metal nanoparticles arranged in the second sub-dielectric layer is larger than the size of the metal nanoparticles arranged in the first sub-dielectric layer.

2. The light emitting device according to claim 1, characterized in that: The first electrode is an anode, and the second electrode is a cathode; the functional layer also includes a hole injection layer and a hole transport layer located between the substrate and the light-emitting layer and arranged in sequence along a direction away from the substrate; the dielectric layer is located between the anode and the hole injection layer.

3. The light emitting device according to claim 1, characterized in that: The first electrode is a cathode, and the second electrode is an anode; the functional layer further comprises an electron transport layer located between the substrate and the light-emitting layer; and the dielectric layer is located between the cathode and the electron transport layer.

4. The light emitting device according to claim 1, characterized in that: The first electrode is a cathode, and the second electrode is an anode; the functional layer also includes an electron injection layer and an electron transport layer located between the substrate and the light-emitting layer and arranged in sequence along a direction away from the substrate; the dielectric layer is located between the cathode and the electron injection layer.

5. The light emitting device according to any one of claims 2 to 4, characterized in that: One of the anode and the cathode is a transparent electrode, and the other is a reflective electrode.

6. The light emitting device according to any one of claims 1 to 4, characterized in that: The size of the metal nanoparticles is 5nm-450nm.

7. The light emitting device according to any one of claims 1 to 4, characterized in that: The metal nanoparticle material includes any one or more of gold, silver and platinum.

8. The light emitting device according to any one of claims 1 to 4, characterized in that: The light emitting device includes an organic light emitting diode or a quantum dot light emitting diode.

9. A display device, characterized in that: A light emitting device comprising the light emitting device according to any one of claims 1 to 8.

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