Quantum dot light emitting diode and display device

Abstract

The invention provides a quantum dot light-emitting diode and a display device, the quantum dot light-emitting diode comprises an anode, a quantum dot light-emitting layer, an electron transport layer and a cathode which are stacked, the quantum dot light-emitting diode further comprises an insertion layer, and the insertion layer is arranged between the electron transport layer and the cathode. The insertion layer is configured to reduce the forward aging rate of the quantum dot light emitting diode. The service life of the quantum dot light-emitting diode can be prolonged, and the influence of the forward aging phenomenon on the output intensity of the quantum dot light-emitting diode can be avoided.

Description

Quantum dot light-emitting diodes and display devices

[0001] This application relates to the field of display technology, and more particularly to a quantum dot light-emitting diode and a display device.

[0002] The lifespan of QLED (Quantum-dot light-emitting diodes) devices is affected by the combined effects of normal aging and forward aging. Studies have found that the effects of forward aging can counteract the effects of normal aging; therefore, devices exhibiting both forward and normal aging have a longer lifespan than those exhibiting only normal aging. However, a significant forward aging effect can impact the device's luminous efficiency, causing issues such as color shift in the display. Therefore, it is currently necessary to control the rate of forward aging to improve both display quality and device lifespan.

[0003]

[0004] This application addresses the shortcomings of related technologies by proposing a quantum dot light-emitting diode and display device to solve the problem of high forward aging rate of devices in related technologies.

[0005] This application provides a quantum dot light-emitting diode, including an anode, a quantum dot light-emitting layer, an electron transport layer, and a cathode stacked together. The quantum dot light-emitting diode also includes an insertion layer disposed between the electron transport layer and the cathode. The insertion layer is configured to reduce the forward aging rate of the quantum dot light-emitting diode.

[0006] In some embodiments, the insertion layer comprises a metallic material, and the chemical inertness of at least one element included in the insertion layer is stronger than that of at least one element included in the cathode.

[0007] In some embodiments, the thickness of the insertion layer ranges from 5 nm to 50 nm in the direction in which the electron transport layer points toward the cathode.

[0008] In some embodiments, the insertion layer comprises a metallic material, and the atomic density of at least one element included in the insertion layer is greater than the atomic density of at least one element included in the cathode.

[0009] In some embodiments, the material of the insertion layer includes at least one of gold, silver, platinum, palladium, rhodium, iridium, ruthenium, and osmium.

[0010] In some embodiments, the insertion layer further includes a cathode material, wherein the content of the cathode material in the insertion layer increases in the direction of the electron transport layer pointing towards the cathode, and the content of the metallic material in the insertion layer decreases.

[0011] In some embodiments, the insertion layer includes a plurality of sub-insertion layers sequentially stacked on the side of the electron transport layer away from the quantum dot light-emitting layer, each of the sub-insertion layers comprising a metallic material; in the direction of the electron transport layer toward the cathode, the chemical inertness of the metallic material of the sub-insertion layers gradually decreases.

[0012] In some embodiments, the insertion layer includes a nanostructure comprising a plurality of nanospheres, and the nanostructure has a hollowed-out area.

[0013] In some embodiments, the nanostructure is a structure with periodic arrangement characteristics, and the characteristic period of the nanostructure ranges from 0.1 nm to 1000 nm.

[0014] In some embodiments, the material of the insertion layer includes an insulating material or a semiconductor material, and the thickness of the insertion layer is less than or equal to 10 nm in the direction of the electron transport layer pointing towards the cathode, and the material of the insertion layer has tunneling characteristics.

[0015] In some embodiments, the material of the insertion layer includes at least one of metal oxide, metal nitride, silicon-based oxide, and silicon-based nitride.

[0016] In some embodiments, the material of the insertion layer includes an insulating material or a semiconductor material, and the thickness of the insertion layer is greater than 10 nm in the direction of the electron transport layer pointing towards the cathode; the insertion layer has a plurality of holes penetrating the insertion layer.

[0017] In some embodiments, the total area of ​​all the holes in the insertion layer projected onto the surface of the insertion layer facing the cathode is a first area, and the total area of ​​the region enclosed by the outer edge of the surface of the insertion layer facing the cathode is a second area, wherein the ratio of the first area to the second area is greater than or equal to 10%.

[0018] In some embodiments, the absolute value of the difference between the work function of the material of the insertion layer and the work function of the material of the cathode is less than or equal to 1 eV.

[0019] This application also provides a quantum dot light-emitting diode, including a stacked anode, a quantum dot light-emitting layer, an electron transport layer, and a cathode. The quantum dot light-emitting diode further includes an insertion layer disposed between the electron transport layer and the cathode. The insertion layer includes a metallic material, and the chemical inertness of at least one element included in the insertion layer is stronger than that of at least one element included in the cathode.

[0020] In some embodiments, the thickness of the insertion layer ranges from 5 nm to 50 nm in the direction in which the electron transport layer points toward the cathode.

[0021] In some embodiments, the atomic density of at least one element included in the insertion layer is greater than the atomic density of at least one element included in the cathode.

[0022] In some embodiments, the material of the insertion layer includes at least one of gold, silver, platinum, palladium, rhodium, iridium, ruthenium, and osmium.

[0023] In some embodiments, the insertion layer further includes a cathode material, wherein the content of the cathode material in the insertion layer increases in the direction of the electron transport layer pointing towards the cathode, and the content of the metallic material in the insertion layer decreases.

[0024] In some embodiments, the insertion layer includes a plurality of sub-insertion layers sequentially stacked on the side of the electron transport layer away from the quantum dot light-emitting layer, each of the sub-insertion layers comprising a metallic material; in the direction of the electron transport layer toward the cathode, the chemical inertness of the metallic material of the sub-insertion layers gradually decreases.

[0025] In some embodiments, the absolute value of the difference between the work function of the material of the insertion layer and the work function of the material of the cathode is less than or equal to 1 eV.

[0026] This application also provides a display device, including the quantum dot light-emitting diode as described above.

[0027] The beneficial effects of this application include:

[0028] This application reduces the forward aging rate of quantum dot light-emitting diodes (LEDs) by forming an insertion layer between the electron transport layer and the cathode. Therefore, by reducing the forward aging efficiency, the lifespan of the quantum dot LED is increased while preventing the forward aging phenomenon from affecting the output intensity of the quantum dot LED.

[0029] Additional aspects and advantages of this application will be set forth in part in the description which follows, and will become apparent from the description or may be learned by practice of this application.

[0030] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0031] Figure 1 shows experimental data comparing and contrasting positive aging and normal aging phenomena in related technologies;

[0032] Figure 2 shows a schematic diagram of a quantum dot light-emitting diode provided in an exemplary embodiment of this application;

[0033] Figure 3 shows a schematic diagram of a quantum dot light-emitting diode provided in an exemplary embodiment of this application;

[0034] Figure 4 is a schematic diagram of the structure of a quantum dot light-emitting diode provided by an exemplary embodiment of this application;

[0035] Figure 5 shows a schematic diagram of a quantum dot light-emitting diode provided in an exemplary embodiment of this application;

[0036] Figure 6 shows a schematic diagram of a quantum dot light-emitting diode provided in an exemplary embodiment of this application;

[0037] Figure 7 is a schematic diagram of the structure of a quantum dot light-emitting diode provided in an exemplary embodiment of this application;

[0038] Figure 8 shows a schematic diagram of the cross section along section line AA in Figure 7;

[0039] Figure 9 shows a schematic diagram of a quantum dot light-emitting diode provided in an exemplary embodiment of this application;

[0040] Figure 10 shows a cross-sectional view along section line BB in Figure 9;

[0041] Figure 11 shows a schematic diagram of a quantum dot light-emitting diode provided in an exemplary embodiment of this application;

[0042] Figure 12 shows a cross-sectional view along section line CC in Figure 11;

[0043] Figure 13 shows a schematic diagram of a quantum dot light-emitting diode provided in an exemplary embodiment of this application;

[0044] Figure 14 shows a schematic diagram of a quantum dot light-emitting diode provided in an exemplary embodiment of this application;

[0045] Figure 15 shows a schematic cross-section along section line DD in Figure 14.

[0046] In the figure: 1-Anode; 2-Hole injection layer; 3-Hole transport layer; 4-Quantum dot light-emitting layer; 5-Electron transport layer; 6-Insertion layer; 601-First sub-doped layer; 602-Second sub-doped layer; 603-Third sub-doped layer; 61-First sub-insertion layer; 62-Second sub-insertion layer; 63-Third sub-insertion layer; 6a-Vacuum hole; 7-Cathode.

[0047] The lifespan of QLED (Quantum-dot light-emitting diodes) devices is affected by the combined effects of normal aging and positive aging. Figure 1(a) shows the aging curve of a device exhibiting positive aging at 2mA, while Figure 1(b) shows the relationship between device brightness and driving voltage under the same aging process for devices exhibiting both positive and normal aging. Studies have found that in QLED devices, the effects of positive aging can counteract the effects of normal aging; therefore, devices exhibiting both positive and normal aging have a longer lifespan than those exhibiting only normal aging. However, a significant positive aging effect can impact the device's luminous efficiency, for example, causing color shift issues in the display. The primary source of forward aging is related to the interfacial electrochemical reaction between the electron transport layer and the cathode. For example, when the electron transport layer is made of zinc oxide, forward aging is typically associated with the following factors: 1. The reaction between zinc oxide and the curing atmosphere of the encapsulant (e.g., oxygen, nitrogen); 2. Diffusion reactions between zinc oxide and the electrode, involving zinc oxide and oxygen, such as the diffusion of oxygen ions, the formation of oxygen vacancies, and the adsorption and desorption of oxygen ions; 3. Ligand diffusion reactions of zinc oxide, such as the combination of ligands (molecules or ions) on or inside the zinc oxide surface with metal ions in the cathode to form complexes. Regarding point 1, it is usually caused by the device's storage instability, and the forward aging phenomenon caused by point 1 will weaken or disappear as the device's storage stability increases. However, the factors affecting points 2 and 3 are related to electrochemical reactions and will continue to occur during device operation. Therefore, it is necessary to control the rate of the interfacial electrochemical reaction between the electron transport layer and the cathode to ensure that the forward aging effect can resist normal aging while minimizing its impact on the device's output strength.

[0048] The quantum dot light-emitting diode and display device provided in this application are intended to solve the above-mentioned technical problems in related technologies.

[0049] The quantum dot light-emitting diodes and display devices in the embodiments of this application will now be described in detail with reference to the accompanying drawings. Unless otherwise specified, the features in the following embodiments may complement or combine with each other.

[0050] This application provides a quantum dot light-emitting diode, as shown in FIG2, including an anode 1, a quantum dot light-emitting layer 4, an electron transport layer 5 and a cathode 7 stacked together. The quantum dot light-emitting diode also includes an insertion layer 6 disposed between the electron transport layer 5 and the cathode 7. The insertion layer 6 is configured to reduce the forward aging rate of the quantum dot light-emitting diode.

[0051] This application reduces the forward aging rate of a quantum dot light-emitting diode (LED) by forming an insertion layer 6 between the electron transport layer 5 and the cathode 7. Thus, by reducing the forward aging efficiency, the lifespan of the quantum dot LED is increased while preventing the forward aging phenomenon from affecting the output intensity of the LED.

[0052] In some embodiments, the ability of the insert layer 6 to reduce the forward aging rate can be further characterized by the chemical barrier efficiency of the insert layer 6. In this application, the chemical barrier efficiency of the insert layer 6 is greater than zero and less than 1.

[0053] In some embodiments, the chemical barrier efficiency is calculated using the following formula:

[0054] Chemical barrier efficiency

[0055] Wherein, D1 is the diffusion rate of chemically active material at any film interface of a quantum dot light-emitting diode without insertion layer 6, and D2 is the diffusion rate of chemically active material at any film interface of a quantum dot light-emitting diode with insertion layer 6. It should be noted that the chemical reaction rate can be the diffusion rate of chemically active material in the off state (static) or the diffusion rate of chemically active material in the on state (electrical operation).

[0056] In some embodiments, the chemical barrier efficiency is calculated using the following formula:

[0057] Chemical barrier efficiency

[0058] Wherein, R1 is the chemical reaction rate of any film layer of a quantum dot light-emitting diode without the insertion layer 6, and R2 is the chemical reaction rate of any film layer of a quantum dot light-emitting diode with the insertion layer 6 when the insertion layer 6 is formed; it should be noted that the chemical reaction rate can be the chemical reaction rate of the film layer in the off state (static) or the chemical reaction rate of the film layer in the on state (electrical operation).

[0059] In some embodiments, the chemical barrier efficiency is calculated using the following formula:

[0060] Chemical barrier efficiency

[0061] Wherein, Aging1 is the forward aging rate of a quantum dot light-emitting diode without the insertion layer 6, and Aging2 is the forward aging rate of a quantum dot light-emitting diode with the insertion layer 6.

[0062] In this embodiment, the diffusion rate of chemically active substances at any film interface, the chemical reaction rate of any film layer, or the forward aging rate of the device can be compared with the experimental results of the quantum dot light-emitting diode with and without the insertion layer 6. This can be used to verify that the formation of the insertion layer 6 can reduce the forward aging efficiency of the quantum dot light-emitting diode.

[0063] In some embodiments, the insertion layer 6 is electrically conductive to facilitate the smooth passage of electrons to enable the device to emit light via a drive voltage. In one example, the increase in the overall contact resistance of the quantum dot light-emitting diode after forming the insertion layer 6 is less than 10,000 ohm·cm².

[0064] In some embodiments, the anode 1 is made of a transparent conductive oxide, a metal, or a composite material of a transparent conductive coating and a metal. In some embodiments, the anode 1 may be made of indium tin oxide (ITO), zinc oxide (ZnO), indium zinc oxide (IZO), copper (Cu), gold (Au), indium tin oxide-gold composite material (ITO / Au), or zinc oxide-copper (ZnO / Cu).

[0065] In some embodiments, the quantum dot light-emitting layer 4 is made of group II-VI quantum dots, group III-V quantum dots, cadmium-free quantum dots, core-shell quantum dots, or composite quantum dots. In some embodiments, the quantum dot light-emitting layer 4 can be made of CdSe (cadmium selenide), CdS (cadmium sulfide), CdTe (cadmium telluride), ZnS (zinc sulfide), InP (indium phosphide), GaP (gallium phosphide), CuInS2 (copper indium sulfide), CuInSe2 (copper indium selenide), ZnSe (zinc selenide), CdSe@ZnS (cadmium selenide as the light-emitting core, zinc sulfide as the shell), InP@ZnS (indium phosphide as the light-emitting core, zinc sulfide as the shell), or CdSe@ZnS@CdS@ZnS (cadmium selenide as the light-emitting core, zinc sulfide, cadmium sulfide, and zinc sulfide are stacked sequentially as a multilayer shell).

[0066] In some embodiments, the electron transport layer 5 is made of at least one of zinc oxide (ZnO), ZnO-based composite materials, or zinc oxide hybrid materials.

[0067] In some embodiments, the cathode 7 is made of aluminum (Al), magnesium-silver alloy (Mg:Ag), lithium (Li), calcium (Ca), or barium (Ba).

[0068] In some embodiments, the quantum dot light-emitting diode further includes a hole injection layer 2 and a hole transport layer 3 sequentially stacked on the anode 1 between the anode 1 and the quantum dot light-emitting layer 4. In some embodiments, the material of the hole injection layer 2 may be poly(3,4-ethylenedioxythiophene): polystyrene sulfonate (PEDOT:PSS), polyaniline (PANI), 4,4',4”-tris(N-carbazolyl)triphenylamine (TCTA), copper phthalocyanine (CuPc), or polythiophene and its derivatives. In some embodiments, the material of the hole transport layer 3 may be poly(9,9-dioctylfluorene) (TFB), 4,4',4”-tris(phenyl)(carbazolyl)triamine (TPD), or 4,4'-bis[N-(1-naphthyl)-N-phenylamino]-1,1'-biphenyl (NPB).

[0069] The following embodiments are provided to further illustrate the specific structural composition of the insertion layer 6.

[0070] Example 1

[0071] As shown in Figure 3, the insertion layer 6 comprises a metallic material, and the chemical inertness of at least one element included in the insertion layer 6 is stronger than that of at least one element included in the cathode 7.

[0072] In this embodiment, a more chemically inert metal material is introduced to control the electrochemical reaction at the interface between the electron transport layer 5 and the cathode 7, thereby reducing the forward aging rate of the device.

[0073] In some embodiments, chemical inertness can be verified by conducting electrochemical experiments on the metal material and the cathode 7 material respectively, and by verifying the strength of the chemical inertness based on the results of the electrochemical experiments.

[0074] In some embodiments, the insertion layer 6 may comprise a single metal element or a composite material of at least two metal elements. The cathode 7 may comprise a single metal element or a composite material of at least two metal elements. The chemical inertness of at least one metal element in the insertion layer 6 is stronger than that of at least one metal element in the cathode 7.

[0075] In some examples, the cathode 7 is made of aluminum, and at least one metal element in the intercalation layer 6 is chemically more inert than aluminum. In some embodiments, the cathode 7 is made of a Mg:Ag alloy, and at least one metal element in the intercalation layer 6 is chemically more inert than magnesium.

[0076] In some embodiments, the thickness of the insertion layer 6 in the direction of the electron transport layer 5 pointing towards the cathode 7 ranges from 5 to 50 nm. In some embodiments, the thickness of the insertion layer 6 in the direction of the electron transport layer 5 pointing towards the cathode 7 can be 5 nm, 10 nm, 15 nm, 20 nm, 30 nm, 40 nm, and 50 nm. In one example, the thickness of the insertion layer 6 in the direction of the electron transport layer 5 pointing towards the cathode 7 is 10 nm.

[0077] In some embodiments, the insertion layer 6 comprises a metallic material, and the atomic density of at least one element included in the insertion layer 6 is greater than the atomic density of at least one element included in the cathode 7.

[0078] In some examples, the cathode 7 is made of aluminum, and the insertion layer 6 is made of at least one of gold (Au), silver (Ag), platinum (Pt), palladium (Pd), rhodium (Rh), iridium (Ir), ruthenium (Ru), and osmium (Os).

[0079] In some embodiments, the absolute value of the difference between the work function of the material of the insertion layer 6 and the work function of the material of the cathode 7 is less than or equal to 1 eV. This reduces the impact of the insertion layer 6 on the electrical performance of the cathode 7. In some embodiments, the cathode 7 is made of aluminum (Al), and the insertion layer 6 is made of gold (Au) or ruthenium (Ru). The work function of gold (Au) is 5.19 eV, the work function of ruthenium (Ru) is 5.19 eV, and the work function of aluminum (Al) is 4.26 eV. Furthermore, the reaction rates of Au and Ru with oxygen (O) are very slow, effectively controlling the formation rate of oxygen defects in the electron transport layer 5 (ZnO) during operation. Au and Ru are also much less chemically reactive than Al, effectively blocking the reaction rate between the ligands of the electron transport layer 5 (ZnO) and the cathode 7.

[0080] Example 2

[0081] As shown in Figure 4, the insertion layer 6 includes a metal material and a cathode 7 material. In the direction from the electron transport layer 5 to the cathode 7, the content of the cathode 7 material in the insertion layer 6 increases, while the content of the metal material in the insertion layer 6 decreases.

[0082] In this embodiment, by forming an insertion layer 6 with a gradual change in the material content of the metal material and the cathode 7, compared to forming only a metal material, the ability of the insertion layer 6 to control the positive aging rate can be improved, resulting in higher controllability.

[0083] In some embodiments, the gradient layer can be formed by gradient doping with metallic materials.

[0084] In some embodiments, in the direction of the electron transport layer 5 pointing to the cathode 7, the content of the cathode 7 material in the insertion layer 6 increases from 0 to 99%, and the content of the metal material in the insertion layer 6 decreases from 100% to 1%.

[0085] In some embodiments, in the direction of the electron transport layer 5 pointing to the cathode 7, the content of the cathode 7 material in the insertion layer 6 increases from 0 to 50%, and the content of the metal material in the insertion layer 6 decreases from 100% to 50%.

[0086] In some embodiments, the metallic material includes at least one of gold (Au), silver (Ag), platinum (Pt), palladium (Pd), rhodium (Rh), iridium (Ir), ruthenium (Ru), and osmium (Os).

[0087] In some embodiments, the thickness of the insertion layer 6 in the direction of the electron transport layer 5 pointing toward the cathode 7 ranges from 1 nm to 100 nm. In some embodiments, the thickness of the insertion layer 6 can be 1 nm, 2 nm, 3 nm, 4 nm, 5 nm, 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, or 100 nm.

[0088] In some embodiments, as shown in FIG5, the insertion layer 6 includes a first sub-doped layer 601, a second sub-doped layer 602, and a third sub-doped layer 603 sequentially stacked on the electron transport layer 5. The first sub-doped layer 601 has a metal content of 100%, and the cathode 7 has a material content of 0%. The second sub-doped layer 602 has a metal content of 75%, and the cathode 7 has a material content of 25%. The third sub-doped layer 603 has a metal content of 50%, and the cathode 7 has a material content of 50%.

[0089] Example 3

[0090] As shown in Figure 6, the insertion layer 6 includes multiple sub-insertion layers 6 stacked sequentially on the side of the electron transport layer 5 away from the quantum dot light-emitting layer 4, and each sub-insertion layer 6 includes a metallic material; in the direction of the electron transport layer 5 pointing towards the cathode 7, the chemical inertness of the metallic material of the sub-insertion layer 6 gradually weakens.

[0091] In this embodiment, a structure with multiple sub-insertion layers 6 is formed to achieve a gradient effect, which can improve the flexibility of device design and simplify the fabrication process.

[0092] In some embodiments, the metal material in the same sub-insertion layer 6 is the same.

[0093] In some embodiments, the insertion layer 6 includes a first sub-insertion layer 61, a second sub-insertion layer 62, and a third sub-insertion layer 63 sequentially stacked on the electron transport layer 5. The first sub-insertion layer 61 is made of a first metal, the second sub-insertion layer 62 is made of a second metal, and the third sub-insertion layer 63 is made of a third metal, wherein the chemical inertness of the first metal is greater than that of the second metal, and the chemical inertness of the second metal is greater than that of the third metal.

[0094] In some embodiments, the metallic material includes at least one of gold (Au), silver (Ag), platinum (Pt), palladium (Pd), rhodium (Rh), iridium (Ir), ruthenium (Ru), and osmium (Os).

[0095] Example 4

[0096] As shown in Figures 7 to 12, the insertion layer 6 includes a nanostructure, which comprises multiple nanospheres and has a hollowed-out area.

[0097] This embodiment introduces a hollow region with a nanostructure, which can further improve the adjustment of the chemical barrier efficiency of the insertion layer 6, so that the chemical barrier efficiency of the insertion layer 6 is controllable. The electrical conductivity and chemical insulation of the insertion layer 6 can be adjusted by adjusting the size and shape of the hollow region, so as to improve the overall service life of the device without negatively affecting the output strength of the device.

[0098] In some embodiments, as shown in Figures 7 and 8, the nanostructure is a structure in which the shape and size of the hollow areas are randomly arranged.

[0099] In some embodiments, as shown in Figures 9 to 12, the nanostructure is a structure with periodic arrangement characteristics, and the characteristic period of the nanostructure ranges from 0.1 nm to 1000 nm.

[0100] In some embodiments, the characteristic period of the nanostructure can be 0.1 nm, 0.2 nm, 0.5 nm, 1 nm, 5 nm, 20 nm, 100 nm, 500 nm, 800 nm or 1000 nm.

[0101] In some embodiments, as shown in Figures 9 and 10, the hollowed-out region of the nanostructure is a rectangular region arranged in multiple arrays, with a characteristic period of T1.

[0102] In some embodiments, as shown in Figures 11 and 12, the area of ​​the nanostructure other than the hollowed-out area forms multiple rectangular regions arranged in an array, with a characteristic period of T2.

[0103] In some embodiments, the hollowed-out regions of the nanostructure can also be multiple arrayed circular regions, semi-circular regions, triangular regions, hexagonal regions, or irregular regions (not shown in the figure).

[0104] In some embodiments, the aperture ratio of the nanostructure ranges from 1% to 99%. It should be noted that the aperture ratio = area of ​​the hollowed-out region / total area of ​​the entire region. A larger aperture ratio results in higher electrical conductivity and lower chemical insulation. A smaller aperture ratio results in lower electrical conductivity and higher chemical insulation.

[0105] In some embodiments, the aperture ratio of the nanostructure can be 1%, 5%, 10%, 20%, 50%, or 99%.

[0106] In some embodiments, the nanostructure can be made of polymer microspheres, metal oxide microspheres, or metal microspheres. In some embodiments, the nanostructure can be polystyrene (PS) microspheres, polymethyl methacrylate (PMMA) microspheres, or polypropylene (PP) microspheres.

[0107] Example 5

[0108] As shown in Figure 13, the material of the insertion layer 6 includes insulating material or semiconductor material. In the direction from the electron transport layer 5 to the cathode 7, the thickness of the insertion layer 6 is less than or equal to 10 nm, and the material of the insertion layer 6 has tunneling characteristics.

[0109] In this embodiment, the material of the insertion layer 6 is an insulating material or a semiconductor material. By making the thickness of the insertion layer 6 small, the tunneling characteristics of the insertion layer 6 can be used to allow electrons to pass through smoothly, so that the insertion layer 6 has electrical conductivity. At the same time, the insulating or semiconductor characteristics of the insertion layer 6 can give the insertion layer 6 a certain chemical barrier effect.

[0110] In some embodiments, the thickness of the insertion layer 6 can be 1 nm, 2 nm, 3 nm, 4 nm, 5 nm, 6 nm, 7 nm, 8 nm, 9 nm or 10 nm.

[0111] In some embodiments, the material of the insertion layer 6 includes at least one of metal oxide, metal nitride, silicon oxide, and silicon nitride.

[0112] In some embodiments, the material of the insert layer 6 may be alumina (Al2O3) or aluminum oxide (AlO2). x ), magnesium oxide (MgO).

[0113] Example 6

[0114] As shown in Figures 14 and 15, the material of the insertion layer 6 includes insulating material or semiconductor material. In the direction from the electron transport layer 5 to the cathode 7, the thickness of the insertion layer 6 is greater than 10 nm. The insertion layer 6 is provided with multiple holes 6a that penetrate the insertion layer 6.

[0115] In this embodiment, a through hole 6a is formed directly in the insertion layer 6 to allow electrons to pass through smoothly. By controlling the size of the hole, the chemical barrier efficiency of the insertion layer 6 can be regulated.

[0116] In some embodiments, the thickness of the insertion layer 6 can be 15nm, 20nm, 30nm, 40nm, 50nm or 100nm.

[0117] In some embodiments, the aperture of the hole 6a in the insertion layer 6 is greater than 10 nm. In some embodiments, the aperture of the hole 6a in the insertion layer 6 can be 20 nm, 30 nm, 40 nm, 50 nm, or 100 nm.

[0118] In some embodiments, the total area of ​​the orthographic projection of all the holes 6a of the insertion layer 6 onto the surface of the insertion layer 6 facing the cathode 7 is a first area, and the total area of ​​the region enclosed by the outer edge of the surface of the insertion layer 6 facing the cathode 7 is a second area, and the ratio of the first area to the second area is greater than or equal to 10%, in order to avoid affecting device implantation.

[0119] In some embodiments, the ratio of the first area to the second area may be 10%, 20%, or 30%.

[0120] Based on the same inventive concept, this application also provides a method for fabricating a quantum dot light-emitting diode, comprising the following steps:

[0121] A quantum dot light-emitting layer 4, an electron transport layer 5, an insertion layer 6 as described in the previous embodiment, and a cathode 7 are sequentially formed on the anode 1.

[0122] In some embodiments, prior to forming the electron transport layer 5, a hole injection layer 2 and a hole transport layer 3 are sequentially formed on the anode 1.

[0123] Based on the same inventive concept, this application also provides a method for fabricating a quantum dot light-emitting diode, comprising the following steps:

[0124] An insertion layer 6, an electron transport layer 5, a quantum dot light-emitting layer 4, and an anode 1 are sequentially formed on the cathode 7 as described in the previous embodiment.

[0125] In some embodiments, a hole transport layer 3 and a hole injection layer 2 are sequentially formed on the quantum dot light-emitting layer 4 before the anode 1 is formed.

[0126] Based on the same inventive concept, this application also provides a display device, including an array substrate and a quantum dot light-emitting diode as provided in the foregoing embodiments located on the array substrate.

[0127] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

Claims

A quantum dot light-emitting diode, characterized in that, The quantum dot light-emitting diode includes an anode, a quantum dot light-emitting layer, an electron transport layer, and a cathode stacked together. The quantum dot light-emitting diode also includes an insertion layer disposed between the electron transport layer and the cathode. The insertion layer is configured to reduce the forward aging rate of the quantum dot light-emitting diode. The quantum dot light-emitting diode according to claim 1 is characterized in that, The insertion layer comprises a metallic material, and the chemical inertness of at least one element in the insertion layer is stronger than that of at least one element in the cathode. The quantum dot light-emitting diode according to claim 1 is characterized in that, In the direction of the electron transport layer pointing towards the cathode, the thickness of the insertion layer ranges from 5 nm to 50 nm. The quantum dot light-emitting diode according to claim 1 is characterized in that, The insertion layer comprises a metallic material, and the atomic density of at least one element in the insertion layer is greater than the atomic density of at least one element in the cathode. The quantum dot light-emitting diode according to claim 4 is characterized in that, The material of the insertion layer includes at least one of gold, silver, platinum, palladium, rhodium, iridium, ruthenium, and osmium. The quantum dot light-emitting diode according to claim 4 is characterized in that, The insertion layer also includes a cathode material, and in the direction of the electron transport layer pointing towards the cathode, the content of the cathode material in the insertion layer increases, while the content of the metallic material in the insertion layer decreases. The quantum dot light-emitting diode according to claim 2 is characterized in that, The insertion layer includes a plurality of sub-insertion layers stacked sequentially on the side of the electron transport layer away from the quantum dot light-emitting layer, each of the sub-insertion layers comprising a metallic material; in the direction of the electron transport layer toward the cathode, the chemical inertness of the metallic material of the sub-insertion layers gradually decreases. The quantum dot light-emitting diode according to claim 1 is characterized in that, The insertion layer includes a nanostructure comprising multiple nanospheres, and the nanostructure has a hollow area. The quantum dot light-emitting diode according to claim 8 is characterized in that, The nanostructure is a structure with periodic arrangement characteristics, and the characteristic period of the nanostructure ranges from 0.1 nm to 1000 nm. The quantum dot light-emitting diode according to claim 1 is characterized in that, The material of the insertion layer includes insulating material or semiconductor material. In the direction from the electron transport layer to the cathode, the thickness of the insertion layer is less than or equal to 10 nm, and the material of the insertion layer has tunneling characteristics. The quantum dot light-emitting diode according to claim 10 is characterized in that, The material of the insertion layer includes at least one of metal oxide, metal nitride, silicon-based oxide, and silicon-based nitride. The quantum dot light-emitting diode according to claim 1 is characterized in that, The insertion layer is made of insulating material or semiconductor material, and the thickness of the insertion layer is greater than 10 nm in the direction of the electron transport layer pointing to the cathode; the insertion layer has multiple holes penetrating the insertion layer. The quantum dot light-emitting diode according to claim 12 is characterized in that, The total area of ​​all the holes in the insertion layer projected onto the surface of the insertion layer facing the cathode is the first area, and the total area of ​​the region enclosed by the outer edge of the surface of the insertion layer facing the cathode is the second area. The ratio of the first area to the second area is greater than or equal to 10%. The quantum dot light-emitting diode according to claim 1 is characterized in that, The absolute value of the difference between the work function of the material of the insertion layer and the work function of the material of the cathode is less than or equal to 1 eV. A quantum dot light-emitting diode, characterized in that, The quantum dot light-emitting diode includes a stacked anode, a quantum dot light-emitting layer, an electron transport layer, and a cathode. The quantum dot light-emitting diode also includes an insertion layer disposed between the electron transport layer and the cathode. The insertion layer includes a metallic material, and at least one element included in the insertion layer has a stronger chemical inertness than at least one element included in the cathode. The quantum dot light-emitting diode according to claim 15 is characterized in that, In the direction of the electron transport layer pointing towards the cathode, the thickness of the insertion layer ranges from 5 nm to 50 nm. The quantum dot light-emitting diode according to claim 15 is characterized in that, The atomic density of at least one element included in the insertion layer is greater than the atomic density of at least one element included in the cathode. The quantum dot light-emitting diode according to claim 15 is characterized in that, The material of the insertion layer includes at least one of gold, silver, platinum, palladium, rhodium, iridium, ruthenium, and osmium. The quantum dot light-emitting diode according to claim 15 is characterized in that, The insertion layer also includes a cathode material, and in the direction of the electron transport layer pointing towards the cathode, the content of the cathode material in the insertion layer increases, while the content of the metallic material in the insertion layer decreases. The quantum dot light-emitting diode according to claim 15 is characterized in that, The insertion layer includes a plurality of sub-insertion layers stacked sequentially on the side of the electron transport layer away from the quantum dot light-emitting layer, each of the sub-insertion layers comprising a metallic material; in the direction of the electron transport layer toward the cathode, the chemical inertness of the metallic material of the sub-insertion layers gradually decreases. The quantum dot light-emitting diode according to claim 15 is characterized in that, The absolute value of the difference between the work function of the material of the insertion layer and the work function of the material of the cathode is less than or equal to 1 eV. A display device, characterized in that, Including quantum dot light-emitting diodes as described in any one of claims 1 to 21.

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