Light-emitting device and display apparatus

Abstract

This disclosure provides a light-emitting device and a display apparatus, belonging to the field of display technology, which can solve the problem of leakage current in existing light-emitting devices. The light-emitting device of this disclosure includes: a first electrode and a second electrode disposed opposite to each other, a plurality of light-emitting units disposed in layers between the first electrode and the second electrode, and a charge generation layer disposed between adjacent light-emitting units; the charge generation layer includes: a P-type charge generation layer and a first insulating material layer; the first insulating material layer is located on the side of the P-type charge generation layer closer to the first electrode.

Description

Technical Field

[0001] This disclosure belongs to the field of display technology, and specifically relates to a light-emitting device and a display apparatus. Background Technology

[0002] Organic light-emitting diodes (OLEDs) are light-emitting devices that use organic solid-state semiconductors as light-emitting materials. Due to their advantages such as simple fabrication process, low cost, low power consumption, high brightness, and wide operating temperature range, they have broad application prospects.

[0003] Stacked OLED light-emitting devices connect two or more OLED light-emitting units in series through a charge generation layer, which can effectively improve luminous efficiency and extend lifespan by a factor of two. The successful development of stacked OLED light-emitting device technology has made it possible for OLED to be used in automotive displays and medium-to-large-sized products. Summary of the Invention

[0004] This disclosure aims to at least solve one of the technical problems existing in the prior art, and provides a light-emitting device and a display device.

[0005] In a first aspect, embodiments of this disclosure provide a light-emitting device, the light-emitting device comprising: a first electrode and a second electrode disposed opposite to each other, a plurality of light-emitting units disposed in layers between the first electrode and the second electrode, and a charge-generating layer disposed between adjacent light-emitting units; the charge-generating layer comprising: a P-type charge-generating layer and a first insulating material layer;

[0006] The first insulating material layer is located on the side of the P-type charge generation layer near the first electrode.

[0007] In some embodiments, the charge generating layer further includes: a second insulating material layer;

[0008] The second insulating material layer is located on the side of the P-type charge generation layer opposite to the first electrode.

[0009] In some embodiments, the thicknesses of both the first insulating layer and the second insulating layer are less than the thickness of the P-type charge generating layer.

[0010] In some embodiments, the charge generation layer further includes: an auxiliary P-type charge generation layer;

[0011] The auxiliary P-type charge generation layer is located on the side of the second insulating material layer away from the first electrode; the doping concentration of the auxiliary P-type charge generation layer is less than the doping concentration of the P-type charge generation layer.

[0012] In some embodiments, the charge-generating layer further includes: a third insulating material layer;

[0013] The third insulating material layer is located on the side of the auxiliary P-type charge generation layer opposite to the first electrode.

[0014] In some embodiments, the thickness of the third insulating material layer is less than the thickness of the P-type charge generating layer.

[0015] In some embodiments, the charge generation layer further includes: an N-type charge generation layer and a fourth insulating material layer;

[0016] The N-type charge generation layer is located on the side of the third insulating material layer opposite to the first electrode;

[0017] The fourth insulating material layer is located on the side of the N-type charge generation layer opposite to the first electrode.

[0018] In some embodiments, the thickness of the fourth insulating material layer is less than the thickness of the N-type charge generating layer.

[0019] In some embodiments, the charge generation layer further includes: an auxiliary N-type charge generation layer and a fifth insulating material layer;

[0020] The auxiliary N-type charge generation layer is located on the side of the third insulating material layer opposite to the N-type charge generation layer; the doping concentration of the auxiliary N-type charge generation layer is less than the doping concentration of the N-type charge generation layer;

[0021] The fifth insulating material layer is located between the auxiliary N-type charge generation layer and the auxiliary P-type charge generation layer.

[0022] In some embodiments, the thickness of the fifth insulating material layer is less than the thickness of the N-type charge generating layer.

[0023] Secondly, embodiments of this disclosure provide a display device, the display device including the light-emitting device as provided in the first aspect. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of an exemplary light-emitting device.

[0025] Figure 2 This is a schematic diagram of the structure of a light-emitting device provided in an embodiment of the present disclosure.

[0026] Figure 3 for Figure 2 The diagram shows the light-emitting principle of the light-emitting device.

[0027] Figure 4This is a schematic diagram of another light-emitting device provided in an embodiment of the present disclosure.

[0028] Figure 5 for Figure 4 The diagram shows the light-emitting principle of the light-emitting device.

[0029] Figure 6 This is a schematic diagram of the structure of another light-emitting device provided in an embodiment of the present disclosure.

[0030] Figure 7 This is a schematic diagram of another light-emitting device provided in an embodiment of the present disclosure. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer and more explicit, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. It should be noted that the embodiments described herein are only a part of the embodiments of this disclosure, and not all possible embodiments. Generally, the components and their structural relationships shown and described in the accompanying drawings of this disclosure can be arranged and designed in various different configurations. Therefore, the specific structures, relative positions, or connection relationships shown in the accompanying drawings should not be construed as any limitation on the scope of protection of this disclosure. The following detailed description of the embodiments of this disclosure provided in the accompanying drawings is intended to illustrate the specific embodiments selected by this disclosure, so as to enable those skilled in the art to understand the relevant technical solutions, and is not intended to limit the scope of this disclosure as claimed. Based on the embodiments described in this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure. Furthermore, without conflict or contradiction, the various embodiments of this disclosure and the various technical features in each embodiment can be combined or replaced with each other in any reasonable manner to form more implementation methods not directly described but also within the scope of this disclosure.

[0032] Unless otherwise expressly defined, the technical or scientific terms used in this disclosure should be understood to have the ordinary meaning commonly understood by one of ordinary skill in the art to which this disclosure pertains. The terms “first,” “second,” and similar expressions used in this disclosure are used only to distinguish different components and do not indicate any order, quantity, importance, or hierarchical priority. Similarly, words such as “an,” “a,” or “the” do not indicate a quantitative limitation but rather indicate the presence of at least one related object. Words such as “comprising” or “including” mean that the element or object preceding the word encompasses the elements or objects listed after the word and their equivalents, but do not exclude the possibility of other elements or objects; that is, the above statements should be understood as open-ended rather than closed descriptions.

[0033] In this disclosure, "multiple" or "several" refers to two or more items, meaning a quantity containing two or more items. The expression "and / or" describes the relationship between related objects, indicating that three different relationship types can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. The character " / " typically indicates an "or" relationship between the preceding and following related objects, meaning one or at least one of them is chosen. The specific meanings of the above terms are subject to the conventional understanding of those skilled in the art to which this disclosure pertains and are interpreted consistently within the context of this disclosure.

[0034] Figure 1 This is a schematic diagram of an exemplary light-emitting device, such as... Figure 1 As shown, the light-emitting device includes: a first electrode 101 and a second electrode 102 disposed opposite to each other; a plurality of light-emitting units 103 stacked between the first electrode 101 and the second electrode 102; and a charge generation layer CGL disposed between adjacent light-emitting units 103. The charge generation layer CGL includes a P-type charge generation layer PCGL and an N-type charge generation layer NCGL. Each light-emitting unit 103 includes: a hole injection layer HIL, a hole transport layer HTL, an electron blocking layer EBL, a light-emitting layer EML, a hole blocking layer HBL, an electron transport layer ETL, and an electron injection layer EIL disposed sequentially along a direction away from the first electrode 101.

[0035] Two adjacent light-emitting units 103 are electrically connected in series via an N-type charge generation layer NCGL and a P-type charge generation layer PCGL, thus forming a stacked OLED light-emitting device. In the stacked OLED light-emitting device, holes injected by the first electrode 101 are transported layer by layer along the internal energy level path, successively passing through functional layers such as the hole injection layer HIL, the hole transport layer HTL, and the electron blocking layer EBL, and finally reaching the light-emitting layer EML. At the same time, electrons injected by the second electrode 102 are transported layer by layer along the internal energy level path, successively passing through functional layers such as the electron injection layer EIL, the electron transport layer ETL, and the hole blocking layer HBL, and also enter the light-emitting layer EML. Electrons and holes meet in the light-emitting layer EML and form excitons through Coulomb interactions. The excitons then release energy through a radiative transition process, thereby generating visible light.

[0036] In practical applications, the P-type charge generation layer (PCGL) typically needs to possess extremely high conductivity to efficiently inject holes into the light-emitting layer (EML), thus naturally forming a low-resistance lateral path in the horizontal direction. Because the PCGL is continuously distributed throughout the device structure, current easily diffuses laterally through this low-resistance path, leading to lateral leakage and severely affecting the display uniformity and resolution of the light-emitting device.

[0037] Meanwhile, N-type charge generation layers (NCGLs) typically rely on doping with reactive metals (such as lithium and ytterbium) to achieve efficient electron injection. However, due to their small size and high reactivity, these metal atoms readily diffuse and migrate from the original doped region to adjacent functional layers under the influence of electric fields or thermal stress, easily forming unintended shunt channels and causing vertical leakage. This vertical leakage not only increases the dark current of the light-emitting device but may also trigger local short circuits or brightness reduction, further adversely affecting the stability, lifetime, and overall performance of the light-emitting device.

[0038] In order to at least solve one of the above-mentioned technical problems, the present disclosure provides a light-emitting device and a display device. The light-emitting device and display device provided in the present disclosure will be described in further detail below with reference to the accompanying drawings and specific embodiments.

[0039] In a first aspect, embodiments of this disclosure provide a light-emitting device. Figure 2 This is a schematic diagram of the structure of a light-emitting device provided in an embodiment of the present disclosure, such as... Figure 2 As shown, the light-emitting device includes: a first electrode 101 and a second electrode 102 disposed opposite to each other, a plurality of light-emitting units 103 disposed in layers between the first electrode 101 and the second electrode 102, and a charge generation layer CGL disposed between adjacent light-emitting units 103; the charge generation layer CGL includes: a P-type charge generation layer PCGL and a first insulating material layer 104; the first insulating material layer 104 is located on the side of the P-type charge generation layer PCGL near the first electrode 101.

[0040] The first electrode 101 can be either an anode or a cathode; correspondingly, the second electrode 102 can be either a cathode or an anode. In the embodiments of this disclosure, the first electrode 101 can specifically be an anode, and the second electrode 102 can specifically be a cathode.

[0041] The first electrode 101 may have a single-layer or multi-layer structure, and its material may be selected from metals, metal compounds, and combinations thereof. For example, the material of the first electrode 101 may include at least one selected from indium tin oxide (ITO), lithium oxide (Li2O), calcium oxide (CaO), lithium fluoride (LiF), magnesium fluoride (MgF2), silver (Ag), magnesium (Mg), copper (Cu), aluminum (Al), platinum (Pt), palladium (Pd), gold (Au), nickel (Ni), neodymium (Nd), iridium (Ir), chromium (Cr), lithium (Li), calcium (Ca), Ca-LiF alloy, Al-LiF alloy, molybdenum (Mo), titanium (Ti), indium (In), tin (Sn), and zinc (Zn).

[0042] The second electrode 102 may have a single-layer or multi-layer structure, and its material may be selected from metals. For example, the material of the second electrode 102 may include at least one selected from silver (Ag), magnesium (Mg), copper (Cu), aluminum (Al), platinum (Pt), palladium (Pd), gold (Au), nickel (Ni), neodymium (Nd), iridium (Ir), chromium (Cr), lithium (Li), calcium (Ca), Ca-LiF alloy, Al-LiF alloy, molybdenum (Mo), titanium (Ti), indium (In), tin (Sn), and zinc (Zn).

[0043] Each light-emitting unit 103 includes a hole injection layer HIL, a hole transport layer HTL, an electron blocking layer EBL, a light-emitting layer EML, a hole blocking layer HBL, an electron transport layer ETL, and an electron injection layer EIL, which are sequentially disposed along the direction away from the substrate 100.

[0044] The material for the hole injection layer (HIL) can be selected from at least one metal oxide, such as molybdenum oxide (MoO3), titanium oxide (TiO2), vanadium oxide (V2O5), rhenium oxide (ReO3), ruthenium oxide (RuO2), chromium oxide (Cr2O3), zirconium oxide (ZrO2), hafnium oxide (HfO2), tantalum oxide (Ta2O5), silver oxide (Ag2O), tungsten oxide (WO3), and manganese oxide (MnO2). Additionally, dopants with strong electron-withdrawing systems, such as F4TCNQ and HATCN, can also be used. Furthermore, p-type doping of the hole transport material can be performed to optimize hole injection performance.

[0045] The material for the hole transport layer (HTL) can be selected from aromatic amines and carbazole derivatives. These two types of materials typically possess high hole mobility, suitable energy level structures, and good film-forming properties. Among them, typical aromatic amine materials such as NPB (N,N'-diphenyl-N,N'-(1-naphthyl)-1,1'-biphenyl-4,4'-diamine) are widely used in various light-emitting devices due to their excellent hole transport capability and stable amorphous morphology. TPD (N,N'-diphenyl-N,N'-(3-methylphenyl)-1,1'-biphenyl-4,4'-diamine), also a classic aromatic amine derivative, has high hole mobility and good solubility, making it suitable for solution processing. In addition, some aromatic amine materials with large conjugated structures or rigid skeletons, such as BAFLP (9,9-bis[4-(N,N-diphenylamino)phenyl]fluorene) and DFLDPBi (N,N'-diphenyl-N,N'-(9,9-dimethylfluorene-2-yl)biphenyl-4,4'-diamine), have further improved the thermal stability and thin film morphology stability of the materials by introducing fluorene units or spirocyclic structures, which helps to extend the lifetime of light-emitting devices.

[0046] Materials for the electron blocking layer (EBL) can be selected from aromatic amine derivatives, carbazole polymers, and their modified structures. Classical aromatic amine materials such as NPB (N,N'-diphenyl-N,N'-(1-naphthyl)-1,1'-biphenyl-4,4'-diamine) and TAPC (4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline]) are widely used in phosphorescent OLED devices due to their high triplet energy level (approximately 2.87 eV) and excellent hole transport properties. Carbazole derivatives such as CBP (4,4'-bis(9-carbazole)biphenyl), while commonly used as host materials, can also serve as electron blocking layer materials in specific structures. Materials such as mCP (1,3-bis(9-carbazole)benzene), with their high triplet energy level and moderate HOMO energy level, are also suitable for electron blocking layers. Rigid materials containing fluorene or spirofluorene structures, such as BAFLP (9,9-bis[4-(N,N-diphenylamino)phenyl]fluorene) and Spiro-TPD, significantly improve the thermal and morphological stability of thin films by introducing large conjugated or spirocyclic structures, which helps to extend the lifespan of light-emitting devices.

[0047] The emissive layer (EML) is the primary site for carrier recombination and exciton radiative transitions, and its composition directly determines the device's emission color, efficiency, and spectral stability. In full-color displays or white light illumination applications, the emissive layer typically consists of sub-emissive layers that emit red, green, and blue light respectively, namely the red emissive layer (REML), the green emissive layer (GEML), and the blue emissive layer (BEML). Depending on the device architecture, the red, green, and blue emissive layers can be arranged horizontally side-by-side (e.g., for lateral RGB sub-pixel patterning) or vertically stacked (e.g., for white OLED devices).

[0048] Red emissive layers (REML) typically use red phosphorescent materials (such as Ir(piq)3 and Ir(MDQ)2(acac)) or thermally activated delayed fluorescence (TADF) materials to fully utilize triplet excitons and achieve an internal quantum efficiency close to 100%. The host material often uses materials with high triplet energy levels, such as CBP and mCP, to prevent energy backpropagation. Green emissive layers (GEML), in the most sensitive spectral region to the human eye, have particularly high efficiency requirements. Commonly used materials include phosphorescent dyes Ir(ppy)3 and its derivatives, as well as high-performance TADF green light materials. The host material must possess both suitable carrier transport characteristics and high triplet energy levels. Blue emissive layers (BEML), due to their wide bandgap, have the highest requirements for triplet energy levels in the host material (typically above 2.7 eV). Traditionally, fluorescent blue light materials (such as DPVBi and TBPe) are used to ensure device lifetime.

[0049] Materials for the hole blocking layer (HBL) and electron transport layer (ETL) are typically aromatic heterocyclic compounds with excellent electron transport capabilities and suitable energy level structures. For example, imidazole derivatives, including benzimidazole derivatives, imidazole-pyridine derivatives, and benzimidazole-phenanthridine derivatives, usually exhibit high electron affinity and good thermal stability; a representative material is TPBi (1,3,5-tris(1-phenyl-1H-benzimidazole-2-yl)benzene). Azine derivatives, mainly including pyrimidine derivatives and triazine derivatives, often possess deep HOMO levels and high triplet energy levels, making them suitable for phosphorescent OLED light-emitting devices; a representative material is OXD-7 (1,3-bis[2-(4-tert-butylphenyl)-1,3,4-oxadiazol-5-yl]benzene). Nitrogen-containing six-membered ring compounds, such as quinoline derivatives, isoquinoline derivatives, and phenanthroline derivatives, typically exhibit good electron mobility and hole blocking capabilities. Among these, phenanthroline derivatives such as BPhen (4,7-diphenyl-1,10-phenanthroline) and BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline) are typical hole-blocking materials due to their deep HOMO levels, which effectively confine holes. Derivatives containing phosphine oxide substituents, by introducing phosphine oxide substituents (such as diphenylphosphine oxide) into the aforementioned heterocyclic skeleton, can further enhance the material's electron affinity and triplet energy level. Representative materials include TAZ (3-(biphenyl-4-yl)-5-(4-tert-butylphenyl)-4-phenyl-1,2,4-triazole) and its derivative p-EtTAZ, etc.

[0050] Materials for the electron injection layer (EIL) are typically low-work-function alkali metals or their compounds to form effective ohmic contacts or enhance the interfacial dipole effect. Specific materials include, but are not limited to: alkali metal compounds, such as lithium fluoride (LiF), sodium fluoride (NaF), and cesium fluoride (CsF), with LiF being the most commonly used electron injection material. It is usually used in conjunction with an aluminum (Al) cathode to form an interfacial dipole layer through thermal evaporation, significantly reducing the electron injection barrier; elemental metals, such as ytterbium (Yb), magnesium (Mg), and calcium (Ca), which can be used directly as electron injection materials or achieved through co-evaporation or alloying (e.g., Mg:Ag alloys) to achieve stable electron injection; alkali metal complexes, such as lithium 8-hydroxyquinoline (Liq), which can be used as electron injection materials or blended with electron transport materials to improve interfacial stability and process compatibility; and metal oxides or composite systems, such as cesium oxide (Cs₂O) and cesium carbonate (Cs₂CO₃), which generate low-work-function species through decomposition or interfacial reactions, also achieving efficient electron injection.

[0051] The P-type charge generation layer (PCGL) can inject holes into the hole injection layer (HIL) or hole transport layer (HTL) of the adjacent light-emitting unit 103, achieving efficient generation and transport of charge carriers. The PCGL is typically made of an organic material system with high electrical conductivity, achieved through heavy doping of the hole transport material. Specifically, the host material can be selected from aromatic amine derivatives, such as NPB (N,N'-diphenyl-N,N'-(1-naphthyl)-1,1'-biphenyl-4,4'-diamine) and TAPC (4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline]), which possess excellent hole transport properties. The dopants are selected from strong electron-withdrawing organic materials, such as F4TCNQ (2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinone dimethyl ether) and HAT-CN (2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazabenzophenanthrene). These materials have high electron affinity and can accept electrons from the host material to generate free holes, thereby significantly improving the conductivity of the layer.

[0052] The first insulating material layer 104 is disposed on the side of the P-type charge generation layer PCGL near the first electrode 101. It is typically made of an inorganic material with high dielectric constant, good insulation performance, and process compatibility. Specific materials include, but are not limited to: silicon nitride (SiNx), which has a high dielectric constant (approximately 7-9), excellent insulation strength, and a dense thin film structure, effectively blocking lateral charge transport while possessing good thermal stability and resistance to moisture and oxygen penetration, making it one of the most commonly used materials for insulating layers; and aluminum oxide (Al2O3), which has a high dielectric constant (approximately 8-10) and excellent thin film density, allowing for precisely controllable film thickness through processes such as atomic layer deposition (ALD), making it suitable for device structures with stringent requirements for insulating layer thickness and uniformity. Alternatively, silicon oxide (SiOx), silicon oxynitride (SiON), or multilayer composite structures (such as SiNx / SiOx double-layer insulation) can be used to balance insulation performance and stress matching.

[0053] Figure 3 for Figure 2 The schematic diagram of the light-emitting principle of the light-emitting device shown is as follows: Figure 3 As shown, from a quantum mechanical perspective, holes need to traverse the first insulating material layer 104 during injection. Due to the lack of continuity in the energy level orbitals of this layer, and the significant discontinuity in energy levels, holes cannot be transported continuously and smoothly. They must overcome the energy level barrier through tunneling or thermal excitation, thus significantly slowing down the injection rate. This injection barrier caused by the discontinuity in energy levels, while increasing the difficulty of carrier injection to some extent, also provides a physical basis for subsequent leakage current suppression.

[0054] From a thermodynamic perspective, the introduction of the first insulating material layer 104 results in a Gibbs free energy change ΔG of the system being less than zero, which means that the first insulating material layer 104 has higher thermodynamic stability. A stable structure means that this layer is less prone to interface degradation, material diffusion, or structural instability during the operation of the light-emitting device, and can maintain its insulating properties over a long period. This stability not only helps ensure the reliability of the light-emitting device but also has a positive impact on power consumption characteristics.

[0055] In summary, compared to the traditional charge generation layer CGL structure without the first insulating material layer 104, the overall power consumption of the light-emitting device is reduced after introducing the first insulating material layer 104. This is because the first insulating material layer 104 effectively suppresses excessive injection of lateral holes through energy level discontinuity, and reduces the generation of non-radiative recombination paths and parasitic currents due to its thermodynamic stability. More importantly, the first insulating material layer 104 physically forms an effective barrier to lateral leakage current, significantly weakening the leakage current that would easily diffuse laterally through the P-type charge generation layer, and even completely blocking it under optimized conditions. Thus, the placement of the first insulating material layer 104, while ensuring the basic function of hole injection, successfully achieves effective control of lateral leakage current, thereby improving the photoelectric performance and long-term stability of the high-resolution light-emitting device.

[0056] In some embodiments, such as Figure 2 As shown, the charge generation layer CGL further includes a second insulating material layer 105; the second insulating material layer 105 is located on the side of the P-type charge generation layer PCGL away from the first electrode 101.

[0057] The second insulating material layer 105 is disposed on the side of the P-type charge generation layer PCGL facing away from the first electrode 101. From the perspective of the stacked structure of the light-emitting device, the P-type charge generation layer PCGL is located between the first insulating material layer 104 and the second insulating material layer 105, forming a sandwich-like structure. This allows the P-type charge generation layer PCGL to be covered by two insulating material layers in the vertical direction, thereby playing a synergistic role in suppressing lateral leakage. Specifically, the first insulating material layer 104 is closer to the first electrode 101, mainly blocking the lateral current diffusion on that side; the second insulating layer 105 is located on the other side of the P-type charge generation layer, further blocking the possibility of current leakage to other adjacent areas. Together, they constitute a dual suppression barrier against lateral leakage. Through this symmetrical or complementary insulating layer layout, the photoelectric performance and long-term stability of high-resolution light-emitting devices can be improved more effectively.

[0058] In some embodiments, the thicknesses of the first insulating material layer 104 and the second insulating material layer 105 are both less than the thickness of the P-type charge generation layer PCGL.

[0059] The first insulating layer 104 and the second insulating layer 105 are both very thin, for example, about 0.5 nanometers thick, much thinner than the P-type charge generation layer PCGL. This results in the two insulating layers existing at only atomic-layer thickness in the vertical direction, forming an ultrathin sandwich structure. This ultrathin sandwich structure can suppress lateral leakage current by utilizing the energy level discontinuity formed at the interface of the insulating material, without excessively hindering hole tunneling injection in the vertical direction, thus achieving a good balance between leakage current control and carrier transport efficiency. Furthermore, such thin insulating layers can be fabricated using methods such as atomic layer deposition or precision thermal evaporation, ensuring thickness uniformity and interface quality, thereby improving the stability and reliability of high-resolution light-emitting devices.

[0060] Figure 4 This is a schematic diagram of another light-emitting device provided in an embodiment of the present disclosure, as shown below. Figure 4 As shown, the charge generation layer CGL further includes: an auxiliary P-type charge generation layer PCGL'; the auxiliary P-type charge generation layer PCGL' is located on the side of the second insulating material layer 105 away from the first electrode 101; the doping concentration of the auxiliary P-type charge generation layer PCGL' is less than the doping concentration of the P-type charge generation layer PCGL.

[0061] The auxiliary P-type charge generation layer PCGL' can be made of the same material as the P-type charge generation layer PCGL, and it is located on the side of the second insulating material layer 105 opposite to the first electrode 101, thereby forming a multilayer composite structure. The doping concentration of the auxiliary P-type charge generation layer PCGL' is lower than that of the P-type charge generation layer PCGL; for example, the doping concentration of the auxiliary P-type charge generation layer PCGL' can be 10%, and the doping concentration of the auxiliary P-type charge generation layer PCGL' can be 5%.

[0062] Figure 5 for Figure 4 The schematic diagram of the light-emitting principle of the light-emitting device shown is as follows: Figure 5As shown, from a quantum mechanical perspective, the gradient doping configuration results in a degree of discontinuity between the conduction and valence bands in the band structure, meaning the band continuity is reduced. Specifically, the P-type charge generation layer PCGL, located near the hole injection layer HIL, maintains a high doping concentration to ensure efficient hole injection. Conversely, the auxiliary P-type charge generation layer PCGL', located on its opposite side, employs a lower doping concentration. This maintains overall charge generation efficiency while appropriately reducing the conductivity in this region, thereby further suppressing the risk of lateral leakage. This composite film layer combined with gradient doping design effectively optimizes the electrical isolation performance of the light-emitting device in the horizontal direction while ensuring efficient carrier transport in the vertical direction, thus improving the stability and reliability of high-resolution light-emitting devices.

[0063] In some embodiments, such as Figure 4 As shown, the charge generation layer CGL also includes a third insulating material layer 106; the third insulating material layer 106 is located on the side of the auxiliary P-type charge generation layer PCGL' away from the first electrode 101.

[0064] The third insulating material layer 106 is located on the side of the auxiliary P-type charge generation layer PCGL' away from the first electrode 101, thereby forming a multi-layered alternating composite structure. The third insulating material layer 106 further enhances the electrical isolation capability of the overall charge generation layer CGL in the horizontal direction. Together with the first insulating material layer 104 and the second insulating material layer 105, they form a comprehensive insulating coating for the P-type charge generation layer and the auxiliary P-type charge generation layer, thereby more effectively suppressing lateral leakage current and improving the stability and reliability of the high-resolution light-emitting device.

[0065] In some embodiments, the thickness of the third insulating material layer 106 is less than the thickness of the P-type charge generation layer PCGL.

[0066] The thickness of the third insulating layer 106 can be 0.5 nanometers, consistent with the thickness of the first insulating layer 104 and the second insulating layer 105, all at the atomic level, much thinner than the thickness of the P-type charge generation layer PCGL. This ultra-thin design allows the third insulating layer 106 to exist only as an extremely thin interface layer in the vertical direction. This effectively suppresses lateral leakage current by utilizing the discontinuity formed by the insulating material in the band structure, without significantly hindering carrier transport in the vertical direction. This allows for full utilization of the insulation function while minimizing the impact on hole injection efficiency, thus achieving a better balance between leakage current suppression and carrier transport, thereby improving the stability and reliability of high-resolution light-emitting devices.

[0067] Figure 6 This is a schematic diagram of the structure of another light-emitting device provided in an embodiment of the present disclosure, as shown below.Figure 6 As shown, the charge generation layer CGL also includes: an N-type charge generation layer NCGL and a fourth insulating material layer 107; the N-type charge generation layer NCGL is located on the side of the third insulating material layer 106 away from the first electrode 101; the fourth insulating material layer 107 is located on the side of the N-type charge generation layer NCGL away from the first electrode 101.

[0068] The N-type charge generation layer NCGL can efficiently inject electrons into adjacent light-emitting units 103. A fourth insulating material layer 107 covers the N-type charge generation layer NCGL, creating a physical barrier with energy level discontinuities above the NCGL. This effectively suppresses electron transport in unintended directions, ensuring that electrons are injected only along a predetermined path. Due to its excellent insulation properties, the fourth insulating material layer 107 can suppress leakage current without significantly increasing the driving voltage, while simultaneously forming a stable interface with the N-type charge generation layer NCGL. While ensuring electron injection efficiency, it minimizes the adverse effects of vertical leakage current on the performance of the light-emitting device, significantly improving the stability and reliability of the high-resolution light-emitting device.

[0069] In some embodiments, the thickness of the fourth insulating material layer 107 is less than the thickness of the N-type charge generation layer NCGL.

[0070] The thickness of the fourth insulating layer 107 can be 0.5 nanometers, which is at the atomic level and much smaller than the thickness of the N-type charge generation layer NCGL. This allows the fourth insulating layer 107 to exist only as an extremely thin interface layer in the vertical direction. This effectively suppresses vertical leakage current by utilizing the discontinuity formed by the insulating material in the band structure, without significantly hindering electron injection. This approach maximizes the insulating isolation function while minimizing the impact on electron injection efficiency, achieving a better balance between leakage current suppression and carrier transport, thus providing strong assurance for the stability and reliability of high-resolution light-emitting devices.

[0071] Figure 7 This is a schematic diagram of another light-emitting device provided in an embodiment of the present disclosure, as shown below. Figure 7 As shown, the charge generation layer CGL further includes: an auxiliary N-type charge generation layer NCGL' and a fifth insulating material layer 108; the auxiliary N-type charge generation layer NCGL' is located on the side of the third insulating material layer 106 away from the N-type charge generation layer NCGL; the doping concentration of the auxiliary N-type charge generation layer NCGL' is less than the doping concentration of the N-type charge generation layer NCGL; the fifth insulating material layer 108 is located between the auxiliary N-type charge generation layer NCGL' and the auxiliary P-type charge generation layer PCGL'.

[0072] The auxiliary N-type charge generation layer NCGL' is located on the side of the third insulating material layer 106 away from the N-type charge generation layer NCGL. Its doping concentration is lower than that of the N-type charge generation layer NCGL. Through this gradient doping configuration, the N-type charge generation layer on the side close to the light-emitting unit 103 maintains a high doping concentration to ensure efficient electron injection capability. Meanwhile, the auxiliary N-type charge generation layer NCGL' on the opposite side adopts a lower doping concentration. While maintaining the overall charge generation efficiency, it appropriately reduces the conductivity of this region, thereby further suppressing the risk of leakage.

[0073] The fifth insulating layer 108 is located between the auxiliary N-type charge generation layer NCGL' and the auxiliary P-type charge generation layer PCGL', serving a dual function of isolation and interface control. Through this series of multilayer composite, gradient doping, and multi-insulating layer synergistic design structures, efficient carrier transport in the charge generation layer CGL can be ensured while effectively suppressing leakage risks in different directions, providing a solid guarantee for the stability and reliability of high-resolution light-emitting devices.

[0074] In some embodiments, the thickness of the fifth insulating material layer 108 is less than the thickness of the N-type charge generation layer NCGL.

[0075] The fifth insulating layer 108 has a thickness of 0.5 nanometers, which is at the atomic level and much smaller than the thickness of the N-type charge generation layer NCGL. This allows the fifth insulating layer 108 to exist as an extremely thin interface layer in the vertical direction. This effectively suppresses vertical leakage current by utilizing the discontinuity formed by the insulating material in the band structure, without significantly hindering electron injection. This approach maximizes the insulating isolation function while minimizing the impact on electron injection efficiency, achieving a better balance between leakage current suppression and carrier transport. This provides a strong guarantee for the stability and reliability of high-resolution light-emitting devices.

[0076] Secondly, this disclosure also provides a display device, which includes the light-emitting device provided in any of the above embodiments. Specifically, the display device can be a variety of electronic devices with display functions, such as mobile phones, laptops, tablets, smart TVs, automotive displays, wearable devices, etc., covering multiple application areas such as consumer electronics, automotive displays, and smart homes. This disclosure does not impose any special limitations on this. In addition to the included light-emitting device, the display device also includes other components necessary for realizing the display function, such as driving circuits, control chips, power management modules, housing structures, heat dissipation components, etc. These components are all content that can be understood and configured accordingly by those skilled in the art based on conventional technical knowledge, and do not need to be described in detail here. Therefore, this document does not elaborate on the above components, nor should it be considered as any limitation on the scope of protection of this disclosure.

[0077] It should be noted that, for clarity and to facilitate a direct understanding of the relative relationships between the structures, the dimensions of layers, regions, and related components in the accompanying drawings may be appropriately exaggerated. This does not represent the true proportions of the actual product. Furthermore, it should be understood that when an element or layer is referred to as being "on" another element or layer, it can mean either that it is directly above that other element or layer, or that there are one or more intermediate layers or elements between them. Similarly, when an element or layer is referred to as being "below" another element or layer, it can mean either that it is directly below that other element or layer, or that there are one or more intermediate layers or elements between them. It should also be understood that when a layer or element is referred to as being "between" two layers or two elements, it can mean either that it is the only layer or element between them, or that there are one or more intermediate layers or elements between them. Throughout this specification, similar reference numerals are used to indicate similar elements to enhance consistency and readability.

[0078] In the several embodiments provided in this disclosure, it should be understood that the disclosed apparatus and its related structures can be implemented in various other ways. For example, the apparatus embodiments described above are merely illustrative, and the positional relationships between the components illustrated or described represent only a logical functional relative positional layout. In actual implementation, different positional arrangements can be adopted according to specific design requirements, process conditions, or application scenarios. Therefore, these illustrations or descriptions should not be regarded as limitations on the scope of protection of this disclosure.

[0079] In the embodiments disclosed herein, the descriptions using terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples" refer to the inclusion of a specific feature, structure, material, or characteristic described in connection with that embodiment or example in at least one embodiment or example of this specification. In this specification, the illustrative expressions of the above terms do not necessarily all refer to the same embodiment or example, but may refer to different embodiments or examples. Furthermore, the described specific features, structures, materials, or characteristics can be combined or combined in any appropriate manner in one or more embodiments or examples, provided that no contradiction or conflict arises. Those skilled in the art can reasonably make the above combinations based on the disclosure of this specification.

[0080] It is understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of this disclosure, and this disclosure is not limited thereto. For those skilled in the art, various modifications and improvements can be made based on the content disclosed in this specification without departing from the spirit and substance of this disclosure, and these modifications and improvements should also be considered as being covered by the protection scope of this disclosure.

Claims

1. A light-emitting device, characterized in that, The light-emitting device includes: a first electrode and a second electrode disposed opposite to each other, a plurality of light-emitting units stacked between the first electrode and the second electrode, and a charge-generating layer located between adjacent light-emitting units; the charge-generating layer includes: a P-type charge-generating layer and a first insulating material layer; The first insulating material layer is located on the side of the P-type charge generation layer near the first electrode.

2. The light-emitting device according to claim 1, characterized in that, The charge-generating layer further includes: a second insulating material layer; The second insulating material layer is located on the side of the P-type charge generation layer opposite to the first electrode.

3. The light-emitting device according to claim 2, characterized in that, The thicknesses of the first insulating material layer and the second insulating material layer are both less than the thickness of the P-type charge generating layer.

4. The light-emitting device according to claim 2, characterized in that, The charge generation layer further includes: an auxiliary P-type charge generation layer; The auxiliary P-type charge generation layer is located on the side of the second insulating material layer away from the first electrode; the doping concentration of the auxiliary P-type charge generation layer is less than the doping concentration of the P-type charge generation layer.

5. The light-emitting device according to claim 4, characterized in that, The charge-generating layer further includes: a third insulating material layer; The third insulating material layer is located on the side of the auxiliary P-type charge generation layer opposite to the first electrode.

6. The light-emitting device according to claim 5, characterized in that, The thickness of the third insulating material layer is less than the thickness of the P-type charge generating layer.

7. The light-emitting device according to claim 5, characterized in that, The charge generation layer further includes: an N-type charge generation layer and a fourth insulating material layer; The N-type charge generation layer is located on the side of the third insulating material layer opposite to the first electrode; The fourth insulating material layer is located on the side of the N-type charge generation layer opposite to the first electrode.

8. The light-emitting device according to claim 7, characterized in that, The thickness of the fourth insulating material layer is less than the thickness of the N-type charge generating layer.

9. The light-emitting device according to claim 7, characterized in that, The charge generation layer further includes: an auxiliary N-type charge generation layer and a fifth insulating material layer; The auxiliary N-type charge generation layer is located on the side of the third insulating material layer opposite to the N-type charge generation layer; the doping concentration of the auxiliary N-type charge generation layer is less than the doping concentration of the N-type charge generation layer; The fifth insulating material layer is located between the auxiliary N-type charge generation layer and the auxiliary P-type charge generation layer.

10. The light-emitting device according to claim 9, characterized in that, The thickness of the fifth insulating material layer is less than the thickness of the N-type charge generating layer.

11. A display device, characterized in that, The display device includes a light-emitting device as described in any one of claims 1 to 10.

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