Display substrate, electroluminescent device and preparation method thereof

Abstract

A display substrate (200), an electroluminescent device (300) and a preparation method, the display substrate (200) comprises: a substrate (201); a pixel definition layer (202) disposed on the substrate (201), wherein the pixel definition layer (202) comprises a plurality of openings (2021), the plurality of openings (2021) correspond to a plurality of sub-pixel regions (2022), the plurality of sub-pixel regions (2022) comprise at least a first sub-pixel region (2022a) and a second sub-pixel region (2022b); a first color quantum dot layer (203) disposed in the first sub-pixel region (2022a); a second color quantum dot layer (204) disposed in the second sub-pixel region (2022b); a first auxiliary layer (205) comprising at least a first part (205a) and a second part (205b) spaced from each other, the first part (205a) is disposed on a side of the first color quantum dot layer (203) away from the substrate (201); the second part (205b) is disposed on a side of the second color quantum dot layer (204) close to the substrate (201), the first auxiliary layer (205) can avoid the second color quantum dot material formed later to be left on the first color quantum dot layer (203), thereby avoiding color mixing and improving the color gamut of the quantum dot electroluminescent device (300).

Description

Technical Field

[0001] The embodiments of this disclosure relate to a display substrate, an electroluminescent device, and a method for fabricating the same. Background Technology

[0002] Quantum dots (QDs), as novel light-emitting materials, possess advantages such as high light purity, high quantum efficiency, tunable color emission, and long lifespan, making them a current research hotspot in novel light-emitting materials. Therefore, quantum dot light-emitting diodes (QLEDs) using quantum dot materials as the light-emitting layer have become a major research direction for novel display devices. With continuous improvements in quantum efficiency, QLED devices can achieve light emission in smaller areas, thereby enabling display products to achieve higher resolutions.

[0003] High-resolution AMQLEDs (Active Matrix Quantum Dot Light Emitting Diodes) have garnered increasing attention due to their potential advantages in wide color gamut and long lifetime. Research on these LEDs is deepening, and their quantum efficiency is continuously improving, essentially reaching industrialization levels. Further industrialization using new processes and technologies has become a future development trend. Due to the inherent properties of quantum dot materials, they are generally fabricated using mask evaporation, printing, or other methods. However, mask evaporation methods suffer from difficulties in alignment, low yield rates, and the inability to achieve smaller luminous areas, thus failing to meet current demands for high-resolution displays. Summary of the Invention

[0004] This disclosure provides at least one embodiment of a display substrate, an electroluminescent device, and a method for fabricating the same. The first auxiliary layer in the display substrate includes at least a first portion and a second portion spaced apart from each other. The first portion of the first auxiliary layer is disposed on the side of the first color quantum dot layer away from the substrate, and the second portion of the first auxiliary layer is disposed on the side of the second color quantum dot layer close to the substrate. The first auxiliary layer can prevent the second color quantum dot material formed later from remaining on the first color quantum dot layer, thereby avoiding the problem of color mixing and improving the color gamut of the subsequently formed electroluminescent device.

[0005] This disclosure provides at least one embodiment of a display substrate, the display substrate comprising: a substrate; a pixel defining layer disposed on the substrate, wherein the pixel defining layer includes a plurality of openings, the plurality of openings corresponding to a plurality of sub-pixel regions, the plurality of sub-pixel regions including at least a first sub-pixel region and a second sub-pixel region; a first color quantum dot layer disposed in the first sub-pixel region; a second color quantum dot layer disposed in the second sub-pixel region; and a first auxiliary layer including at least a first portion and a second portion spaced apart from each other, the first portion being disposed on the side of the first color quantum dot layer away from the substrate; and the second portion being disposed on the side of the second color quantum dot layer close to the substrate.

[0006] For example, in at least one embodiment of the display substrate provided in this disclosure, the first portion and the second portion have the same thickness and are made of the same material.

[0007] For example, in the display substrate provided in at least one embodiment of this disclosure, the materials of the first part and the second part are metal oxides.

[0008] For example, in a display substrate provided in at least one embodiment of this disclosure, the surface roughness of the metal oxide is less than 3 nm.

[0009] For example, in a display substrate provided in at least one embodiment of this disclosure, the first auxiliary layer further includes a third portion, which is disposed on the side of the pixel defining layer away from the substrate, and the first portion, the second portion and the third portion are not connected to each other.

[0010] For example, at least one embodiment of the present disclosure provides a display substrate that further includes a second auxiliary layer and a third color quantum dot layer disposed in the third sub-pixel region, wherein the second auxiliary layer is at least disposed on the side of the second color quantum dot layer away from the substrate.

[0011] For example, in at least one embodiment of the display substrate provided in this disclosure, the first auxiliary layer and the second auxiliary layer are made of different materials.

[0012] For example, in a display substrate provided in at least one embodiment of this disclosure, the material of the first auxiliary layer includes an electron transport type oxide, the material of the second auxiliary layer includes a hole transport type oxide, and at least a portion of the first auxiliary layer is in contact with the first color quantum dot layer, and at least a portion of the second auxiliary layer is in contact with the third color quantum dot layer.

[0013] For example, in a display substrate provided in at least one embodiment of this disclosure, the first color quantum dot layer is a blue quantum dot layer, the second color quantum dot layer is one of a red quantum dot layer and a green quantum dot layer, and the third color quantum dot layer is the other of the green quantum dot layer and the red quantum dot layer.

[0014] For example, in the display substrate provided in at least one embodiment of this disclosure, the first color quantum dot layer includes a first color quantum dot, the second color quantum dot layer includes a second color quantum dot, and the third color quantum dot layer includes a third color quantum dot, all of which include a quantum dot body and a ligand connected to the quantum dot body. The structure of the ligand is ABC type, where A is a coordinating group connected to the quantum dot body; B is a reactant of the photosensitive group after irradiation; and C is -COOH.

[0015] For example, in the display substrate provided in at least one embodiment of this disclosure, the first color quantum dot layer includes a first color quantum dot, the second color quantum dot layer includes a second color quantum dot, and the third color quantum dot layer includes a third color quantum dot, all of which include a quantum dot body and a ligand connected to the quantum dot body. The structure of the ligand is a mixture of AB-type ligands and AC-type ligands, where A is a coordinating group connected to the quantum dot body; B is a reactant of the photosensitive group after irradiation; and C is -COOH.

[0016] For example, in a display substrate provided in at least one embodiment of this disclosure, the second auxiliary layer includes at least a fourth portion, a fifth portion, and a sixth portion spaced apart from each other. The fourth portion is disposed on the side of the first portion away from the substrate and is at least partially in contact with the first portion. The fifth portion is disposed on the side of the second color quantum dot layer away from the substrate. The sixth portion is disposed on the side of the third color quantum dot layer close to the substrate.

[0017] For example, in a display substrate provided in at least one embodiment of this disclosure, the second auxiliary layer further includes a seventh portion that is spaced apart from the fourth portion, the fifth portion and the sixth portion. The seventh portion is disposed on the side of the third portion away from the substrate and is at least partially in contact with the third portion.

[0018] For example, in a display substrate provided in at least one embodiment of this disclosure, the first auxiliary layer further includes an eighth portion that is spaced apart from the first portion, the second portion and the third portion, and the eighth portion is disposed on the side of the sixth portion near the substrate.

[0019] For example, in a display substrate provided in at least one embodiment of this disclosure, the materials of the first auxiliary layer and the second auxiliary layer both include at least one of electron transport oxide and hole transport oxide.

[0020] For example, in the display substrate provided in at least one embodiment of this disclosure, the materials of the first auxiliary layer and the second auxiliary layer both include at least one of zinc oxide, tin oxide, gallium nitride, aluminum nitride, molybdenum oxide, nickel oxide, zirconium oxide, vanadium oxide, zinc oxide doped with magnesium, tin, gallium, indium, zirconium, hafnium, yttrium, lithium or aluminum, and tin oxide doped with magnesium, tin, gallium, indium, zirconium, hafnium, yttrium, lithium or aluminum.

[0021] For example, in a display substrate provided in at least one embodiment of this disclosure, the first auxiliary layer includes a stacked first layer structure and a second layer structure, the first layer structure being located on the side of the second layer structure closer to the substrate, and the material of the first layer structure including at least one of electron transport oxide and hole transport oxide;

[0022] The general formula for the second layer structure includes: Where A is -(CH2)nCH3, n is less than or equal to 4; M is -(CH2)x, x is less than or equal to 6; P includes At least one of them.

[0023] For example, in a display substrate provided in at least one embodiment of this disclosure, the second auxiliary layer includes a stacked third layer structure and a fourth layer structure, wherein the third layer structure is located on the side of the fourth layer structure near the substrate, and the material of the third layer structure includes at least one of electron transport oxide and hole transport oxide;

[0024] The general formula for the fourth layer structure includes: Where A is -(CH2)nCH3, n is less than or equal to 4; M is -(CH2)x, x is less than or equal to 6; P includes At least one of them.

[0025] For example, in the display substrate provided in at least one embodiment of this disclosure, the materials of the first layer structure and the third layer structure both include at least one of zinc oxide, tin oxide, gallium nitride, aluminum nitride, molybdenum oxide, nickel oxide, zirconium oxide, vanadium oxide, zinc oxide doped with magnesium, tin, gallium, indium, zirconium, hafnium, yttrium, lithium or aluminum, and tin oxide doped with magnesium, tin, gallium, indium, zirconium, hafnium, yttrium, lithium or aluminum.

[0026] At least one embodiment of this disclosure also provides an electroluminescent device, which includes a display substrate as described in any of the above claims, and a first electrode and a first functional layer stacked on the substrate, wherein the first electrode is disposed on the side of the first functional layer near the substrate; the first functional layer and the first electrode are both stacked in a plurality of sub-pixel regions, and the stacked first functional layer and the first electrode are located between the first color quantum dot layer and the substrate, between the second color quantum dot layer and the substrate, and between the third color quantum dot layer and the substrate.

[0027] For example, in the electroluminescent device provided in at least one embodiment of this disclosure, the first auxiliary layer and the first functional layer are made of the same material, and in the direction perpendicular to the main surface of the substrate, the thickness of the first functional layer is 4 to 5 times the thickness of the first auxiliary layer.

[0028] For example, in an electroluminescent device provided in at least one embodiment of this disclosure, the thickness of the first color quantum dot layer is 4 to 5 times the thickness of the first auxiliary layer.

[0029] At least one embodiment of this disclosure also provides a method for fabricating an electroluminescent device. The method includes: providing a substrate; forming a pixel defining layer on the substrate, the pixel defining layer including a plurality of openings to form a plurality of sub-pixel regions spaced apart from each other, the plurality of sub-pixel regions including at least a first sub-pixel region and a second sub-pixel region; forming a first color quantum dot layer in the first sub-pixel region; forming a second color quantum dot layer in the second sub-pixel region; the method further includes: forming a first auxiliary layer after forming the first color quantum dot layer and before forming the second color quantum dot layer, wherein the first auxiliary layer includes at least a first portion and a second portion spaced apart from each other, the first portion being disposed on the side of the first color quantum dot layer away from the substrate; and the second portion being disposed on the side of the second color quantum dot layer close to the substrate.

[0030] For example, in the preparation method provided in at least one embodiment of this disclosure, before forming the first color quantum dot layer, the method further includes: forming a first functional layer on the substrate, wherein the first functional layer and the first auxiliary layer are bonded to each other in the second sub-pixel region and the third sub-pixel region.

[0031] For example, in the preparation method provided in at least one embodiment of this disclosure, the material of the first auxiliary layer includes at least one of electron transport oxide and hole transport oxide, and the first auxiliary layer is formed by magnetron sputtering.

[0032] For example, in the preparation method provided in at least one embodiment of this disclosure, the material of the first auxiliary layer includes at least one of zinc oxide, tin oxide, gallium nitride, aluminum nitride, molybdenum oxide, nickel oxide, zirconium oxide, vanadium oxide, zinc oxide doped with magnesium, tin, gallium, indium, zirconium, hafnium, yttrium, lithium or aluminum, and tin oxide doped with magnesium, tin, gallium, indium, zirconium, hafnium, yttrium, lithium or aluminum.

[0033] For example, in the preparation method provided in at least one embodiment of this disclosure, forming the first auxiliary layer includes forming a stacked first layer structure and a second layer structure, the first layer structure being on the side of the second layer structure close to the substrate, and forming the first layer structure includes: applying at least one of an electron transport oxide and a hole transport oxide onto the substrate by magnetron sputtering; forming the second layer structure includes immersing the substrate on which the first layer structure is formed in a solution of a silane coupling agent, the solution of the silane coupling agent including a first group containing a perfluorinated terminator.

[0034] For example, in the preparation method provided in at least one embodiment of this disclosure, the material of the first layer structure includes at least one of zinc oxide, tin oxide, gallium nitride, aluminum nitride, molybdenum oxide, nickel oxide, zirconium oxide, vanadium oxide, zinc oxide doped with magnesium, tin, gallium, indium, zirconium, hafnium, yttrium, lithium or aluminum, and tin oxide doped with magnesium, tin, gallium, indium, zirconium, hafnium, yttrium, lithium or aluminum.

[0035] For example, in the preparation method provided in at least one embodiment of this disclosure, a second auxiliary layer is formed at least on the side of the second color quantum dot layer away from the substrate; a third color quantum dot layer is formed on the side of the second auxiliary layer away from the substrate and in the third sub-pixel region; the first auxiliary layer and the second auxiliary layer are made of different materials.

[0036] For example, in the preparation method provided in at least one embodiment of this disclosure, the material of the second auxiliary layer includes at least one of electron transport oxide and hole transport oxide, and the second auxiliary layer is formed by magnetron sputtering.

[0037] For example, in the preparation method provided in at least one embodiment of this disclosure, the material of the second auxiliary layer includes at least one of zinc oxide, tin oxide, gallium nitride, aluminum nitride, molybdenum oxide, nickel oxide, zirconium oxide, vanadium oxide, zinc oxide doped with magnesium, tin, gallium, indium, zirconium, hafnium, yttrium, lithium or aluminum, and tin oxide doped with magnesium, tin, gallium, indium, zirconium, hafnium, yttrium, lithium or aluminum.

[0038] For example, in the preparation method provided in at least one embodiment of this disclosure, forming the second auxiliary layer includes forming a stacked third layer structure and a fourth layer structure, wherein the third layer structure is on the side of the fourth layer structure close to the substrate, and forming the third layer structure includes: applying at least one of an electron transport oxide and a hole transport oxide onto the substrate by magnetron sputtering; forming the fourth layer structure includes immersing the substrate on which the third layer structure is formed in a solution of a silane coupling agent, wherein the solution of the silane coupling agent includes a third group containing a perfluorinated terminal.

[0039] For example, in the preparation method provided in at least one embodiment of this disclosure, the material of the third layer structure includes at least one of zinc oxide, tin oxide, gallium nitride, aluminum nitride, molybdenum oxide, nickel oxide, zirconium oxide, vanadium oxide, zinc oxide doped with magnesium, tin, gallium, indium, zirconium, hafnium, yttrium, lithium or aluminum, and tin oxide doped with magnesium, tin, gallium, indium, zirconium, hafnium, yttrium, lithium or aluminum.

[0040] For example, in the preparation method provided in at least one embodiment of this disclosure, forming the first color quantum dot layer includes: depositing a first color quantum dot material on the first functional layer, and cross-linking and developing the first color quantum dot material in the first sub-pixel region to form the first color quantum dot layer; forming the second color quantum dot layer includes: depositing a second color quantum dot material on the first functional layer, and cross-linking and developing the second color quantum dot material in the second sub-pixel region to form the second color quantum dot layer; forming the third color quantum dot layer includes: depositing a third color quantum dot material on the first functional layer, and cross-linking and developing the third color quantum dot material in the third sub-pixel region to form the third color quantum dot layer.

[0041] For example, in the preparation method provided in at least one embodiment of this disclosure, the material of the first auxiliary layer includes an electron transport type oxide, the material of the second auxiliary layer includes a hole transport type oxide, and at least a portion of the first auxiliary layer is in contact with the first color quantum dot layer, and at least a portion of the second auxiliary layer is in contact with the third color quantum dot layer.

[0042] For example, in the preparation method provided in at least one embodiment of this disclosure, after forming the first color quantum dot layer, the second color quantum dot layer and the third color quantum dot layer, a second functional layer and a third functional layer are sequentially formed on the side of the first color quantum dot layer, the second color quantum dot layer and the third color quantum dot layer away from the substrate.

[0043] For example, at least one embodiment of the present disclosure provides a preparation method that further includes: forming a first electrode on the substrate before forming the first functional layer, wherein the material of the first electrode includes a transparent conductive metal oxide or a conductive polymer; forming a second electrode on the side of the third functional layer away from the substrate, wherein the material of the second electrode includes a conductive metal or a conductive metal oxide.

[0044] For example, in the preparation method provided in at least one embodiment of this disclosure, the first auxiliary layer and the second auxiliary layer are sequentially formed on the surface of the pixel defining layer away from the substrate. Attached Figure Description

[0045] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the accompanying drawings of the embodiments will be briefly described below. Obviously, the drawings described below only relate to some embodiments of this disclosure and are not intended to limit this disclosure.

[0046] Figure 1 A schematic diagram of a quantum dot layer patterning process;

[0047] Figure 2 for Figure 1 Quantum dot patterns formed during the actual manufacturing process;

[0048] Figure 3 A schematic cross-sectional view of a display substrate provided in at least one embodiment of this disclosure;

[0049] Figure 4 This is a schematic cross-sectional view of another display substrate provided in at least one embodiment of the present disclosure;

[0050] Figure 5 A cross-sectional structural diagram of a double-layer structure in which the first auxiliary layer is stacked, provided in at least one embodiment of the present disclosure;

[0051] Figure 6 A cross-sectional structural diagram of a double-layer structure in which the second auxiliary layer is stacked, provided in at least one embodiment of the present disclosure;

[0052] Figure 7 This is a schematic cross-sectional view of another display substrate provided in at least one embodiment of the present disclosure;

[0053] Figure 8 A schematic cross-sectional view of an electroluminescent device provided in at least one embodiment of this disclosure;

[0054] Figure 9 A schematic cross-sectional view of another electroluminescent device provided for at least one embodiment of this disclosure;

[0055] Figure 10 A flowchart illustrating the fabrication process of an electroluminescent device provided for at least one embodiment of this disclosure;

[0056] Figure 11 A flowchart illustrating the fabrication process of another electroluminescent device provided in at least one embodiment of this disclosure;

[0057] Figure 12 A schematic diagram illustrating the fabrication process of an electroluminescent device provided in at least one embodiment of this disclosure;

[0058] Figure 13 The graphs show the emission peaks of blank glass, blank glass with quantum dots (without MPA ligands), blank glass with zinc oxide and quantum dots (without MPA ligands), and blank glass with zinc oxide and quantum dots (with MPA ligands) under irradiation with 400 nm excitation light.

[0059] Figure 14 This is a schematic diagram of the emission peak formed by red quantum dots (without MPA ligand) after sputtering ZnO and development, under irradiation with 400 nm excitation light.

[0060] Figure 15 This is a schematic diagram showing the emission peak formed by red quantum dots (containing MPA ligands) under 400nm excitation light after sputtering ZnO, developing (washing away the red quantum dots), and then depositing green quantum dots.

[0061] Figure 16 A schematic diagram showing the emission peaks formed by green quantum dots (containing MPA ligands) under 400 nm excitation light after sputtering ZnO and development; and

[0062] Figure 17 This is a schematic diagram showing the emission of light after green quantum dots are sputtered and cross-linked, followed by the deposition of red quantum dots (without MPA ligands) and development (washing away the red quantum dots). Detailed Implementation

[0063] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the described embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0064] Unless otherwise defined, the technical or scientific terms used in this disclosure shall have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms “first,” “second,” and similar terms used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as “comprising” or “including” mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as “connected” or “linked” are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as “upper,” “lower,” “left,” and “right” are used only to indicate relative positional relationships, and these relative positional relationships may change accordingly when the absolute position of the described objects changes.

[0065] In the fabrication of quantum dot electroluminescent devices, the patterning of quantum dot layers is primarily achieved through inkjet printing. However, limitations of inkjet printing equipment restrict the resolution of the patterned quantum dot layers to within 200 ppi. Furthermore, when using inkjet printing for quantum dot layer patterning, a pixel boundary layer needs to be prepared before depositing each functional layer. The quantum dot ink in each functional layer tends to climb onto this pixel boundary layer, sometimes even reaching the top plateau region. This significantly affects the morphology and thickness uniformity of the formed quantum dot film, severely impacting the lifetime and light emission uniformity of the quantum dot electroluminescent device, ultimately hindering its mass production. This problem is particularly pronounced for high-resolution display panels. Therefore, it is necessary to investigate a quantum dot layer patterning method to improve the resolution of quantum dot electroluminescent devices.

[0066] For example, photolithography can be used to directly pattern quantum dot electroluminescent devices in full color. However, this process also has drawbacks: quantum dots of different colors will remain in each pixel area, leading to color mixing problems. Figure 1 This is a schematic diagram of a quantum dot layer patterning process, such as... Figure 1As shown, a substrate 101 is provided, on which a first electrode 102 is formed. A pixel defining layer 104 is formed on one side of the substrate 101 where the first electrode 102 is formed. The pixel defining layer 104 includes a plurality of openings to form a plurality of sub-pixel regions. Red quantum dot material is applied to each sub-pixel region to form a red quantum dot film 105'. The process of patterning the red quantum dot film 105' includes: using a first mask 1031 to block the sub-pixel region in the middle region and the rightmost sub-pixel region so that light can illuminate the leftmost region. The red quantum dot film 105' is exposed to sub-pixel regions to allow the red quantum dot material in these regions to undergo a cross-linking reaction. This completes the exposure process. Uncross-linked red quantum dot material is then cleaned to remove it from the middle and rightmost sub-pixel regions, thus forming a red quantum dot pattern 105. Green quantum dot material is then applied to each sub-pixel region to form a green quantum dot film 106'. The patterning process for the green quantum dot film 106' includes using a second mask 1032 to expose the red quantum dot material in the sub-pixel regions. The leftmost and rightmost sub-pixel areas are blocked to allow light to reach the middle sub-pixel area, causing the green quantum dot material in that sub-pixel area to undergo a cross-linking reaction, thus completing the exposure process of the green quantum dot film 106'. The green quantum dot material that has not undergone the cross-linking reaction is then cleaned to remove it from the leftmost and rightmost sub-pixel areas, forming the green quantum dot pattern 106. Blue quantum dot material is then applied to each sub-pixel area to form the blue quantum dot film 107'. The process of patterning the blue quantum dot film includes: using a third mask 1033 to block the leftmost sub-pixel area and the middle sub-pixel area so that light can shine on the rightmost sub-pixel area, causing the blue quantum dot material in the sub-pixel area to undergo a cross-linking reaction, thus completing the exposure process of the blue quantum dot film 107'; and cleaning the blue quantum dot material that has not undergone a cross-linking reaction to remove the blue quantum dot material in the leftmost and middle sub-pixel areas, thus forming the blue quantum dot pattern 107.

[0067] It should be noted that, Figure 1The process diagram shown represents an ideal fabrication flow chart, where uncrosslinked quantum dots are completely removed during each cleaning step. However, in actual fabrication, the problem of incomplete cleaning of uncrosslinked quantum dots always arises, resulting in residual uncrosslinked quantum dots. For example, red quantum dots remain in the middle and rightmost sub-pixel areas; green quantum dots remain in the leftmost and rightmost sub-pixel areas; and blue quantum dots remain in the middle and leftmost sub-pixel areas. Figure 2 for Figure 1 Quantum dot patterns formed during actual manufacturing processes, such as Figure 2 As shown, green quantum dot material and blue quantum dot material remain on the side of the red quantum dot pattern 105 away from the substrate 101; red quantum dot material remains on the side of the green quantum dot pattern 106 close to the substrate 101; blue quantum dot material remains on the side of the green quantum dot pattern 106 away from the substrate 101; and green quantum dot material and red quantum dot material remain on the side of the blue quantum dot pattern 107 close to the substrate 101.

[0068] In addition, quantum dot patterns can also be formed using indirect photolithography, which utilizes a sacrificial layer to pattern the quantum dot luminescent material. Specifically, indirect photolithography involves forming a sacrificial layer in the area where the quantum dot luminescent material needs to be removed before forming the quantum dot luminescent material. Then, the quantum dot luminescent material is patterned using a sacrificial layer elution method. This indirect photolithography also suffers from the phenomenon that, for example, green and blue quantum dot materials remain on the side of the red quantum dot pattern away from the substrate; red quantum dot materials remain on the side of the green quantum dot pattern closer to the substrate; blue quantum dot materials remain on the side of the green quantum dot pattern away from the substrate; and green and red quantum dot materials remain on the side of the blue quantum dot pattern closer to the substrate. In other words, both direct and indirect photolithography suffer from the problem of residual quantum dot materials on the previously formed quantum dot patterns.

[0069] The inventors of this disclosure have noted that a first auxiliary layer can be formed on the surface of a red quantum dot pattern that has already undergone a cross-linking reaction, making it easier to wash away the green quantum dot material subsequently formed thereon, and a second auxiliary layer can be formed on the surface of a green quantum dot pattern that has already undergone a cross-linking reaction, making it easier to wash away the blue quantum dot material subsequently formed thereon, thereby reducing the phenomenon of color mixing.

[0070] At least one embodiment of this disclosure provides a quantum dot electroluminescent device, which includes: a substrate; a pixel defining layer disposed on the substrate, the pixel defining layer including a plurality of openings corresponding to a plurality of sub-pixel regions, the plurality of sub-pixel regions including at least a first sub-pixel region and a second sub-pixel region, a first color quantum dot layer disposed in the first sub-pixel region, a second color quantum dot layer disposed in the second sub-pixel region, and a first auxiliary layer including at least a first portion and a second portion spaced apart from each other, the first portion being disposed on the side of the first color quantum dot layer away from the substrate; the second portion being disposed on the side of the second color quantum dot layer close to the substrate. The first auxiliary layer can prevent the second color quantum dot material formed later from remaining on the first color quantum dot layer, thereby avoiding the problem of color mixing and improving the color gamut of the quantum dot electroluminescent device.

[0071] For example, Figure 3 This is a schematic cross-sectional view of a display substrate provided in at least one embodiment of the present disclosure, as shown below. Figure 3 As shown, the display substrate 200 includes: a substrate 201; and a pixel defining layer 202 disposed on the substrate 201. The pixel defining layer 202 includes a plurality of openings 2021, each opening 2021 corresponding to a plurality of sub-pixel regions 2022. For example, one opening 2021 corresponds to one sub-pixel region 2022. Quantum dot layers of different colors are formed in the plurality of openings 2021 to define the plurality of openings 2021 as a plurality of sub-pixel regions 2022, and the plurality of sub-pixel regions 2022 are distinguished according to the different colors of the quantum dot layers formed in the openings 2021. The sub-pixel region 2022 includes at least a first sub-pixel region 2022a and a second sub-pixel region 2022b. The first color quantum dot layer 203 is disposed in the first sub-pixel region 2022a, and the second color quantum dot layer 204 is disposed in the second sub-pixel region 2022b. The first auxiliary layer 205 includes at least a first portion 205a and a second portion 205b spaced apart from each other. The first portion 205a is disposed on the side of the first color quantum dot layer 203 away from the substrate 201, and the second portion 205b is disposed on the side of the second color quantum dot layer 204 closer to the substrate 201. Figure 3 In the structure shown, the first auxiliary layer 205 is also provided on the side of the pixel defining layer 202 away from the substrate 201, except for the opening. That is, the first auxiliary layer 205 is formed as a whole layer. However, due to the existence of step difference caused by the opening of the pixel defining layer, the first auxiliary layer 205 of each sub-pixel area is disconnected from each other.

[0072] For example, in one example, such as Figure 3As shown, since there is a step difference between the portion of the pixel defining layer 202 other than the opening 2021 and the opening 2021, the first portion 205a and the second portion 205b are separated from each other by the portion of the pixel defining layer 202 other than the opening 2021.

[0073] For example, in one instance, the materials of the first part 205a and the second part 205b are metal oxides. For instance, the surface roughness of this metal oxide is less than 3 nm. It should be noted that this surface roughness refers to RMS roughness.

[0074] For example, in one example, such as Figure 3 As shown, the first auxiliary layer 205 also includes a third portion 205c, which is disposed on the side of the pixel defining layer 202 away from the substrate 201, and the first portion 205a, the second portion 205b and the third portion 205c are not connected to each other.

[0075] For example, in one example, the first auxiliary layer 205 has the properties of electron transport and / or electron blocking, and the connection between the first auxiliary layer 205 and the uncrosslinked quantum dot material thereon is weak, making the uncrosslinked quantum dot material easier to clean off. This avoids the second color quantum dot material formed later from remaining on the first color quantum dot layer, thereby avoiding the problem of color mixing and improving the color gamut of the subsequently formed electroluminescent device.

[0076] For example, the thickness ratio of the first auxiliary layer 205 to the first color quantum dot layer 203 and the second color quantum dot layer 204 can both be 0.1 to 0.5. For example, the thickness of the first auxiliary layer 205 is 5nm-10nm, and the thickness of the first auxiliary layer 205 is 20nm-50nm.

[0077] For example, it should be noted that the quantum dot layers of various colors include quantum dots of different colors, which can be semiconductor nanocrystals and can have various shapes, such as spherical, conical, multi-armed, and / or cubic nanoparticles, nanotubes, nanowires, nanofibers, nanoplate particles, quantum rods, or quantum sheets. Here, the quantum rod can be a quantum dot with an aspect ratio (length:width ratio) greater than about 1, for example, greater than or equal to about 2, greater than or equal to about 3, or greater than or equal to about 5. For example, the quantum rod can have an aspect ratio less than or equal to about 50, less than or equal to about 30, or less than or equal to about 20.

[0078] For example, the quantum dot may have a particle diameter of, for example, about 1 nm to about 100 nm, about 1 nm to about 80 nm, about 1 nm to about 50 nm, or about 1 nm to 20 nm (for non-spherical shapes, the average maximum particle length).

[0079] For example, the band gap of a quantum dot can be controlled according to its size and composition, and thus the emission wavelength can be controlled. For example, as the size of the quantum dot increases, it can have a narrow band gap and thus be configured to emit light in a relatively long wavelength region, while as the size of the quantum dot decreases, it can have a wide band gap and thus be configured to emit light in a relatively short wavelength region. For example, a quantum dot can be configured to emit light in a predetermined wavelength region of the visible light region according to its size and / or composition. For example, the quantum dot can be configured to emit blue light, red light, or green light, and the blue light can have a peak emission wavelength (λmax) for example in the range of about 430 nm to about 480 nm, the red light can have a peak emission wavelength (λmax) for example in the range of about 600 nm to about 650 nm, and the green light can have a peak emission wavelength (λmax) for example in the range of about 520 nm to about 560 nm.

[0080] For example, the average particle size of the quantum dots configured to emit blue light may be, for example, less than or equal to about 4.5 nm, and for example, less than or equal to about 4.3 nm, less than or equal to about 4.2 nm, less than or equal to about 4.1 nm, or less than or equal to about 4.0 nm. Within this range, for example, the average particle size of the quantum dots may be from about 2.0 nm to about 4.5 nm, for example, from about 2.0 nm to about 4.3 nm, from about 2.0 nm to about 4.2 nm, from about 2.0 nm to about 4.1 nm, or from about 2.0 nm to about 4.0 nm.

[0081] The quantum dot may have a quantum yield of, for example, greater than or equal to about 10%, greater than or equal to about 20%, greater than or equal to about 30%, greater than or equal to about 50%, greater than or equal to about 60%, greater than or equal to about 70%, or greater than or equal to about 90%.

[0082] The quantum dot may have a relatively narrow half-width (FWHM). Here, FWHM is the width corresponding to half the wavelength of the peak absorption point, and when the FWHM is narrow, it can be configured to emit light in a narrower wavelength region and achieve higher color purity. The quantum dots may have a FWHM of, for example, less than or equal to about 50 nm, less than or equal to about 49 nm, less than or equal to about 48 nm, less than or equal to about 47 nm, less than or equal to about 46 nm, less than or equal to about 45 nm, less than or equal to about 44 nm, less than or equal to about 43 nm, less than or equal to about 42 nm, less than or equal to about 41 nm, less than or equal to about 40 nm, less than or equal to about 39 nm, less than or equal to about 38 nm, less than or equal to about 37 nm, less than or equal to about 36 nm, less than or equal to about 35 nm, less than or equal to about 34 nm, less than or equal to about 33 nm, less than or equal to about 32 nm, less than or equal to about 31 nm, less than or equal to about 30 nm, less than or equal to about 29 nm, or less than or equal to about 28 nm. Within the range, it may have, for example, an FWHM of about 2nm to about 49nm, about 2nm to about 48nm, about 2nm to about 47nm, about 2nm to about 46nm, about 2nm to about 45nm, about 2nm to about 44nm, about 2nm to about 43nm, about 2nm to about 42nm, about 2nm to about 41nm, about 2nm to about 40nm, about 2nm to about 39nm, about 2nm to about 38nm, about 2nm to about 37nm, about 2nm to about 36nm, about 2nm to about 35nm, about 2nm to about 34nm, about 2nm to about 33nm, about 2nm to about 32nm, about 2nm to about 31nm, about 2nm to about 30nm, about 2nm to about 29nm, or about 2nm to about 28nm.

[0083] For example, the quantum dots may include group II-VI semiconductor compounds, group III-V semiconductor compounds, group IV-VI semiconductor compounds, group IV semiconductors, group I-III-VI semiconductor compounds, group I-II-IV-VI semiconductor compounds, group II-III-V semiconductor compounds, or combinations thereof. The group II-VI semiconductor compounds may be selected, for example, from: binary compounds such as CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, MgSe, MgS, or mixtures thereof; ternary compounds such as CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZn Te, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, MgZnSe, MgZnS, or mixtures thereof; and quaternary compounds such as HgZnTeS, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, HgZnSTe, or mixtures thereof, but not limited thereto. The III-V semiconductor compounds may be selected, for example, from: binary compounds such as GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, or mixtures thereof; ternary compounds such as GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, or mixtures thereof; and quaternary compounds such as GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, InAlPSb, or mixtures thereof, but are not limited thereto. The IV-VI group semiconductor compounds may be selected, for example, from: binary compounds such as SnS, SnSe, SnTe, PbS, PbSe, PbTe, or mixtures thereof; ternary compounds such as SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, or mixtures thereof; and quaternary compounds such as SnPbSSe, SnPbSeTe, SnPbSTe, or mixtures thereof, but are not limited thereto.The group IV semiconductors may be selected, for example, from: elemental (monological) semiconductors such as Si, Ge, or mixtures thereof; and binary semiconductor compounds such as SiC, SiGe, and mixtures thereof, but are not limited thereto. The group I-III-VI semiconductor compounds may be, for example, CuInSe2, CuInS2, CuInGaSe, CuInGaS, or mixtures thereof, but are not limited thereto. The group I-II-IV-VI semiconductor compounds may be, for example, CuZnSnSe, CuZnSnS, or mixtures thereof, but are not limited thereto. The group II-III-V semiconductor compounds may include, for example, InZnP, but are not limited thereto.

[0084] The quantum dots can have a substantially uniform concentration distribution or a locally different concentration distribution, and the quantum dots include the elemental semiconductor, the binary semiconductor compound, the ternary semiconductor compound, or the quaternary semiconductor compound.

[0085] For example, the quantum dots may include cadmium-free (Cd) quantum dots. Cadmium-free quantum dots are quantum dots that do not contain cadmium (Cd). Cadmium (Cd) causes serious environmental / health problems and is an element restricted under the Restriction of Hazardous Substances Directive (RoHS) in many countries, and therefore cadmium-free quantum dots can be used effectively.

[0086] In one embodiment, the quantum dot may be a semiconductor compound comprising at least one of zinc (Zn) and tellurium (Te) and selenium (Se). For example, the quantum dot may be a Zn-Te semiconductor compound, a Zn-Se semiconductor compound, and / or a Zn-Te-Se semiconductor compound. For example, the amount of tellurium (Te) in the Zn-Te-Se semiconductor compound may be less than the amount of selenium (Se). The semiconductor compound may have a peak emission wavelength (λ maximum) in a wavelength region of less than or equal to about 480 nm, for example, about 430 nm to about 480 nm, and may be configured to emit blue light.

[0087] For example, the quantum dot may be a semiconductor compound comprising at least one of indium (In), zinc (Zn), and phosphorus (P). For example, the quantum dot may be an In-P semiconductor compound and / or an In-Zn-P semiconductor compound. For example, in the In-Zn-P semiconductor compound, the molar ratio of zinc (Zn) to indium (In) may be greater than or equal to about 25. The semiconductor compound may have a peak emission wavelength (λ maximum) in a wavelength region less than about 700 nm, for example, from about 600 nm to about 650 nm, and may be configured to emit red light.

[0088] The quantum dots may have a core-shell structure, with one quantum dot surrounding another. For example, the core and shell of the quantum dot may have an interface, and at least one element of the core or shell may have a concentration gradient at the interface, wherein the concentration of the element in the shell decreases toward the core. For example, the material composition of the shell of the quantum dot has a higher band gap than the material composition of the core of the quantum dot, and thereby the quantum dot may exhibit a quantum confinement effect.

[0089] The quantum dot may have a quantum dot core and a multi-layered quantum dot shell surrounding the core. Here, the multi-layered shell has at least two shells, wherein each shell may be a single composition, an alloy, and / or have a concentration gradient.

[0090] For example, the shells of a multilayered structure that are farther from the core may have a higher band gap than the shells closer to the core, and thus the quantum dot may exhibit a quantum confinement effect.

[0091] For example, a quantum dot having a core-shell structure may include, for example, a core comprising a first semiconductor compound comprising zinc (Zn) and at least one of tellurium (Te) and selenium (Se); and a shell disposed on at least a portion of the core and having a composition different from that of the core, comprising a second semiconductor compound.

[0092] For example, the first semiconductor compound may be a Zn-Te-Se based semiconductor compound comprising zinc (Zn), tellurium (Te) and selenium (Se), for example, a Zn-Se based semiconductor compound comprising a small amount of tellurium (Te), for example, a semiconductor compound represented by ZnTexSe1-x, wherein x is greater than about 0 and less than or equal to 0.05.

[0093] For example, in a first semiconductor compound based on Zn-Te-Se, the molar amount of zinc (Zn) may be higher than the molar amount of selenium (Se), and the molar amount of selenium (Se) may be higher than the molar amount of tellurium (Te). For example, in the first semiconductor compound, the molar ratio of tellurium (Te) to selenium (Se) may be less than or equal to about 0.05, less than or equal to about 0.049, less than or equal to about 0.048, less than or equal to about 0.047, less than or equal to about 0.045, less than or equal to about 0.044, less than or equal to about 0.043, less than or equal to about 0.042, less than or equal to about 0.041, less than or equal to about 0.04, less than or equal to about 0.039, less than or equal to about 0.035, less than or equal to about 0.03, less than or equal to about 0.00, or less than or equal to about 0.00. 29. Less than or equal to about 0.025, Less than or equal to about 0.024, Less than or equal to about 0.023, Less than or equal to about 0.022, Less than or equal to about 0.021, Less than or equal to about 0.02, Less than or equal to about 0.019, Less than or equal to about 0.018, Less than or equal to about 0.017, Less than or equal to about 0.016, Less than or equal to about 0.015, Less than or equal to about 0.014, Less than or equal to about 0.013, Less than or equal to about 0.012, Less than or equal to about 0.011, or Less than or equal to about 0.01. For example, in the first semiconductor compound, the molar ratio of tellurium (Te) to zinc (Zn) may be less than or equal to about 0.02, less than or equal to about 0.019, less than or equal to about 0.018, less than or equal to about 0.017, less than or equal to about 0.016, less than or equal to about 0.015, less than or equal to about 0.014, less than or equal to about 0.013, less than or equal to about 0.012, less than or equal to about 0.011, or less than or equal to about 0.010.

[0094] The second semiconductor compound may include, for example, group II-VI semiconductor compounds, group III-V semiconductor compounds, group IV-VI semiconductor compounds, group IV semiconductors, group I-III-VI semiconductor compounds, group I-II-IV-VI semiconductor compounds, group II-III-V semiconductor compounds, or combinations thereof. Examples of the group II-VI semiconductor compounds, group III-V semiconductor compounds, group IV-VI semiconductor compounds, group IV semiconductors, group I-III-VI semiconductor compounds, group I-II-IV-VI semiconductor compounds, and group II-III-V semiconductor compounds are the same as those described above.

[0095] For example, the second semiconductor compound may include zinc (Zn), selenium (Se), and / or sulfur (S). For example, the shell may include ZnSeS, ZnSe, ZnS, or combinations thereof. For example, the shell may include at least one inner shell disposed near the core and an outermost shell disposed at the outermost edge of the quantum dot. The inner shell may include ZnSeS, ZnSe, or combinations thereof, and the outermost shell may include ZnS. For example, the shell may have a concentration gradient of components, and the amount of, for example, sulfur (S) may increase as it leaves the core.

[0096] For example, a quantum dot having a core-shell structure may include: a core comprising a third semiconductor compound comprising at least one of indium (In), zinc (Zn), and phosphorus (P); and a shell disposed on at least a portion of the core and comprising a fourth semiconductor compound having a composition different from that of the core.

[0097] In the In-Zn-P based third semiconductor compound, the molar ratio of zinc (Zn) to indium (In) can be greater than or equal to about 25. For example, in the In-Zn-P based third semiconductor compound, the molar ratio of zinc (Zn) to indium (In) can be greater than or equal to about 28, greater than or equal to about 29, or greater than or equal to about 30. For example, in the In-Zn-P based third semiconductor compound, the molar ratio of zinc (Zn) to indium (In) can be less than or equal to about 55, for example, less than or equal to about 50, less than or equal to about 45, less than or equal to about 40, less than or equal to about 35, less than or equal to about 34, less than or equal to about 33, or less than or equal to about 32.

[0098] The fourth semiconductor compound may include, for example, group II-VI semiconductor compounds, group III-V semiconductor compounds, group IV-VI semiconductor compounds, group IV semiconductors, group I-III-VI semiconductor compounds, group I-II-IV-VI semiconductor compounds, group II-III-V semiconductor compounds, or combinations thereof. Examples of the group II-VI semiconductor compounds, group III-V semiconductor compounds, group IV-VI semiconductor compounds, group IV semiconductors, group I-III-VI semiconductor compounds, group I-II-IV-VI semiconductor compounds, and group II-III-V semiconductor compounds are the same as those described above.

[0099] For example, the fourth semiconductor compound may include zinc (Zn) and sulfur (S), and optionally selenium (Se). For example, the shell may include ZnSeS, ZnSe, ZnS, or combinations thereof. For example, the shell may include at least one inner shell disposed near the core and an outermost shell disposed at the outermost edge of the quantum dot. At least one of the inner shell and the outermost shell may include the fourth semiconductor compound ZnS, ZnSe, or ZnSeS.

[0100] The light-emitting layer can have a thickness of, for example, from about 5 nm to about 200 nm, within that range, for example, from about 10 nm to about 150 nm, from about 10 nm to about 100 nm, or from about 10 nm to about 50 nm. The quantum dot QDs contained in the light-emitting layer EML can be laminated into one or more layers, for example, two layers. However, embodiments of the present disclosure are not limited thereto, and the quantum dot QDs can be laminated into one to ten layers. Depending on the type (or kind) of quantum dot QDs used and the desired emission wavelength of the light, the quantum dot QDs can be laminated into any suitable number of layers.

[0101] Quantum dots can have relatively deep HOMO levels, for example, HOMO levels greater than or equal to about 5.4 eV, and within the range, for example greater than or equal to about 5.5 eV, for example greater than or equal to about 5.6 eV, for example greater than or equal to about 5.7 eV, for example greater than or equal to about 5.8 eV, for example greater than or equal to about 5.9 eV, for example greater than or equal to about 6.0 eV. Within the stated range, the HOMO energy levels of the quantum dot layer 13 can be, for example, about 5.4 eV to about 7.0 eV, for example, about 5.4 eV to about 6.8 eV, for example, about 5.4 eV to about 6.7 eV, for example, about 5.4 eV to about 6.5 eV, for example, about 5.4 eV to about 6.3 eV, for example, about 5.4 eV to about 6.2 eV, for example, about 5.4 eV to about 6.1 eV, and within the stated range, for example, about 5.5 eV to about 7.0 eV, for example, about 5.5 eV to about 6.8 eV, for example, about 5.5 eV to about 6.7 eV, for example, about 5.5 eV to about 6.5 eV, for example, about 5.5 eV to about 6.3 eV, for example, about 5.5 eV to about 6.2 eV, for example, about 5.5 eV to about 6.1 eV, for example, about 5.5 eV to about 7.0 eV, for example, about 5.6 eV to about 6.8 eV, for example, about 5.6 eV to about 6.7 eV, for example, about 5.6 eV to about 6.5 eV, for example, about 5.6 eV to about 6.3 eV, for example, about 5.6 eV to about 6.2 eV, for example, about 5 From 0.6 eV to about 6.1 eV, within the range of, for example, from about 5.7 eV to about 7.0 eV, for example, from about 5.7 eV to about 6.8 eV, for example, from about 5.7 eV to about 6.7 eV, for example, from about 5.7 eV to about 6.5 eV, for example, from about 5.7 eV to about 6.3 eV, for example, from about 5.7 eV to about 6.2 eV, for example, from about 5.7 eV to about 6.1 eV, within the range of, for example, from about 5.8 eV to about 7.0 eV, for example, from about 5.8 eV to about 6.8 eV, for example, from about 5.8 eV. eV to 6.7 eV, for example, about 5.8 eV to 6.5 eV, for example, about 5.8 eV to 6.3 eV, for example, about 5.8 eV to 6.2 eV, for example, about 5.8 eV to 6.1 eV, within the range of, for example, about 6.0 eV to 7.0 eV, for example, about 6.0 eV to 6.8 eV, for example, about 6.0 eV to 6.7 eV, for example, about 6.0 eV to 6.5 eV, for example, about 6.0 eV to 6.3 eV, for example, about 6.0 eV to 6.2 eV.

[0102] Quantum dots may have relatively shallow LUMO energy levels, for example, less than or equal to about 3.7 eV, and within the range of, for example, less than or equal to about 3.6 eV, less than or equal to about 3.5 eV, less than or equal to about 3.4 eV, less than or equal to about 3.3 eV, less than or equal to about 3.2 eV, or less than or equal to about 3.0 eV. Within the range of, the LUMO energy levels of quantum dot layer 13 may be about 2.5 eV to about 3.7 eV, about 2.5 eV to about 3.6 eV, about 2.5 eV to about 3.5 eV, about 2.5 eV to about 3.4 eV, about 2.5 eV to about 3.3 eV, about 2.5 eV to about 3.2 eV, about 2.5 eV to about 3.1 eV, about 2.5 eV to about 3.0 eV, or about 2. 8 eV to about 3.7 eV, about 2.8 eV to about 3.6 eV, about 2.8 eV to about 3.5 eV, about 2.8 eV to about 3.4 eV, about 2.8 eV to about 3.3 eV, about 2.8 eV to about 3.2 eV, about 3.0 eV to about 3.7 eV, about 3.0 eV to about 3.6 eV, about 3.0 eV to about 3.5 eV, or about 3.0 eV to about 3.4 eV.

[0103] The quantum dots may have a band gap of about 1.7 eV to about 2.3 eV or about 2.4 eV to about 2.9 eV. Within these ranges, for example, the quantum dot layer 13 may have a band gap of about 1.8 eV to about 2.2 eV or about 2.4 eV to about 2.8 eV, and within these ranges, for example, about 1.9 eV to about 2.1 eV or about 2.4 eV to about 2.7 eV.

[0104] For example, the first color quantum dot layer 203 and the second color quantum dot layer 204 respectively include first color quantum dots and second color quantum dots that are IIB-VIA group semiconductor compounds, and can be binary compounds, ternary compounds or quaternary compounds. For example, the materials of the first color quantum dots and second color quantum dots can be CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, CdSeS, CdSeTe, CdSTe, etc. At least one of ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, and HgZnSTe is selected. Typically, when quantum dots are excited by a blue light source, they emit excitation fluorescence of a specific wavelength. The fluorescence spectrum emitted is determined by the chemical composition and particle size of the quantum dot material. As the particle size increases, the fluorescence spectrum emitted by materials with the same chemical composition redshifts from green to red. The quantum dot materials that emit red light and those that emit green light can be quantum dot materials with the same chemical composition but different particle sizes, or they can be quantum dot materials with different chemical compositions. That is, the first color quantum dots and the second color quantum dots can be prepared from the same material but have different particle sizes, or the first color quantum dots and the second color quantum dots can be prepared from different materials.

[0105] For example, a quantum dot is a nanoscale semiconductor. By applying a certain electric field or light pressure to a nanoscale semiconductor material, the nanoscale semiconductor material will emit light of a specific frequency. The frequency of the emitted light will change with the size of the semiconductor. Therefore, by adjusting the size of the quantum dot, the color of the emitted light can be controlled.

[0106] For example, by controlling the shape, structure, and size of quantum dots, the band gap width, exciton binding energy, and electronic states such as the blue shift of exciton energy can be easily adjusted. As the size of the quantum dot decreases, its spectrum exhibits a blue shift. The smaller the size of the quantum dot, the more significant the blue shift. For instance, for cadmium selenide quantum dots, as the size decreases from 10 nm to 2 nm, the color of the emitted light changes from red to blue. When the size of the cadmium selenide quantum dot is greater than or equal to 2 nm and less than 5 nm, it emits blue light; when the size is greater than or equal to 5 nm and less than 8 nm, it emits green light; and when the size is greater than or equal to 8 nm and less than 10 nm, it emits red light.

[0107] For example, the unique properties of quantum dots are based on their quantum size effect. When particle size enters the nanoscale, size confinement will induce size effect, quantum confinement effect, macroscopic quantum tunneling effect, and surface effect, thereby deriving low-dimensional physical properties in nanoscale systems that differ from microscale systems, giving quantum dots different physicochemical properties. For instance, quantum dots exhibit unique photoluminescence and electroluminescence properties due to quantum size and electrical confinement effects. Compared with organic fluorescent dyes, quantum dots have superior optical properties such as high quantum yield, high photochemical stability, resistance to photolysis, broad excitation and narrow emission, high color purity, and the ability to adjust the emission color by controlling the size of the quantum dots. Thus, quantum dot electroluminescent devices, including quantum dot emitting layers, have advantages such as high luminous efficiency, good stability, long lifetime, high brightness, and wide color gamut.

[0108] For example, in one example, the first color quantum dot layer includes first color quantum dots, the second color quantum dot layer includes second color quantum dots, and the third color quantum dot layer includes third color quantum dots, each including a quantum dot body and a ligand attached to the quantum dot body. The ligands all have an ABC structure, where A is a coordinating group connected to the quantum dot bodies of the first, second, and third color quantum dots respectively. This coordinating group can be -SH, -COOH, -NH2, or a polydentate ligand. B is a reactant after photosensitive group irradiation and is configured to photocrosslink the first, second, or third color quantum dots. This photosensitive group can be alkenyl, carbonyl, epoxy group, or Boc-amino, etc. C is -COOH and is configured to react with the developer.

[0109] For example, on the one hand, the weakly basic developer tetramethylammonium hydroxide (TMAH) reacts with carboxyl groups to form ionic ligands, resulting in good solubility; on the other hand, tetramethylammonium hydroxide (TMAH) is a surfactant with a hydroxyl group at one end (a polar group) and a tetramethylamine group at the other end (a nonpolar group), thus effectively improving the solubility of quantum dots in the developer, which is beneficial for the elution of quantum dots. It should be noted that the developer material can also be a series of polyalkyl quaternary ammonium salts such as tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, and hexadecyltrimethylammonium bromide (CTAB), or it can be a bisquaternary ammonium salt (a type of gemini surfactant) formed by linking monoquaternary ammonium salts.

[0110] For example, a polydentate ligand is a ligand with two or more coordinating atoms. Examples include diethylenetriamine (DEN) and ethylenediaminetetraacetic acid (EDTA).

[0111] For example, in another example, the first color quantum dot layer includes first color quantum dots, the second color quantum dot layer includes second color quantum dots, and the third color quantum dot layer includes third color quantum dots, each including a quantum dot body and a ligand connected to the quantum dot body. The structure of the ligand is a mixture of AB-type ligands and AC-type ligands, where A is a coordinating group connected to the quantum dot bodies of the first color quantum dot, the second color quantum dot, and the third color quantum dot, respectively. This coordinating group can be -SH, -COOH, -NH2, or a polydentate ligand; B is a reactant after photosensitive group is irradiated, and is configured to cause photocrosslinking of the first color quantum dot, the second color quantum dot, or the third color quantum dot; C is -COOH, configured to react with the developer; the photosensitive group can be alkenyl, carbonyl, epoxy group, or Boc-amino, etc.

[0112] For example, AB-type ligands can achieve the photocuring properties of quantum dots, while AC-type ligands can achieve their good elution properties.

[0113] For example, the first color quantum dot layer 203 and the second color quantum dot layer 204 may also include thickeners, coupling agents and accelerators, the contents of which can be adjusted as needed.

[0114] For example, the thickener may be at least one of methyl vinyl MQ silicone resin, polymethyl methacrylate, and polycyanoacrylate. The coupling agent may be at least one of vinyltrimethoxysilane, vinyltriethoxysilane, and vinyl-tris-(2-methoxyethoxy)silane. The accelerator may be N,N-dimethylaniline, N,N-dimethyl-p-toluidine, or 2,4,6-tris(dimethylaminomethyl)phenol.

[0115] For example, the substrate 201 may include a transparent insulating substrate such as a glass substrate or a flexible substrate. The material of the substrate 201 may also be other suitable materials, and the embodiments disclosed herein do not limit this.

[0116] It should be noted that, although Figure 3 Only two openings 2021 are shown, but embodiments of this disclosure are not limited to this and may have more openings 2021, i.e., more sub-pixel regions 2022. Other layer structures, such as organic functional layers and / or electrode structures, may also be disposed between the substrate 201 and the first color quantum dot layer 203 and the second color quantum dot layer 204. For simplification... Figure 3 The layer structure of this part is shown in the figure.

[0117] For example, a quantum dot light-emitting diode in a quantum dot electroluminescent device typically includes a cathode, an anode, and a quantum dot light-emitting layer disposed between the cathode and the anode. It may also include an organic functional layer between the cathode and the quantum dot light-emitting layer, or between the anode and the quantum dot light-emitting layer.

[0118] For example, Figure 4 This is a schematic cross-sectional view of another display substrate provided in at least one embodiment of the present disclosure, as shown below. Figure 4 As shown, the display substrate 200 includes three sub-pixel regions 2022. A first color quantum dot layer 203 is disposed in the first sub-pixel region 2022a, a second color quantum dot layer 204 is disposed in the second sub-pixel region 2022b, and a third color quantum dot layer 206 is disposed in the third sub-pixel region 2022c. For example, the first color quantum dot layer 203 may include red quantum dots, the second color quantum dot layer 204 may include green quantum dots, and the third color quantum dot layer 206 may include blue quantum dots. Thus, the red light emitted from the first color quantum dot layer 203, the green light emitted from the second color quantum dot layer 204, and the blue light emitted from the third color quantum dot layer 206 can be mixed to form white light. Therefore, the quantum dot electroluminescent device can have excellent display color. The materials used for the red, green, and blue quantum dots are not particularly limited, and those skilled in the art can select them based on commonly used materials for red, green, and blue quantum dots. The following explanation will be based on the example of first forming a first color quantum dot layer 203, then forming a second color quantum dot layer 204, and finally forming a third color quantum dot layer 206.

[0119] For example, such as Figure 4As shown, the first auxiliary layer 205 is formed over its entire surface. The first auxiliary layer 205 includes at least a first portion 205a, a second portion 205b, a third portion 205c, and an eighth portion 205d that are spaced apart from each other. The first portion 205a is disposed on the side of the first color quantum dot layer 203 away from the substrate 201. The second portion 205b is disposed on the side of the second color quantum dot layer 204 close to the substrate 201. The third portion 205c is disposed on the side of the pixel defining layer 202 away from the substrate 201. The eighth portion 205d is disposed on the side of the third color quantum dot layer 206 close to the substrate 201. Since there is a step difference between the portion of the pixel defining layer 202 other than the opening 2021 and the opening 2021, the first portion 205a, the second portion 205b, the third portion 205c, and the eighth portion 205d are in a disconnected state during the formation process. For example, the third portion 205c has a height difference from the first portion 205a, the second portion 205b, and the eighth portion 205d in a direction perpendicular to the main surface of the substrate 201. For example, the height difference between the third portion 205c and the first portion 205a, the second portion 205b, and the eighth portion 205d in a direction perpendicular to the main surface of the substrate 201 is greater than the thickness of the third portion 205c in the same direction. For example, the height difference between the third portion 205c and the first portion 205a in a direction perpendicular to the main surface of the substrate 201 is greater than or equal to four times the thickness of the third portion 205c in the same direction, and less than or equal to six times the thickness of the third portion 205c in the same direction. The height difference between the third portion 205c and the second portion 205b in the direction perpendicular to the main surface of the substrate 201 is greater than or equal to 8 times the thickness of the third portion 205c in the direction perpendicular to the main surface of the substrate 201, and less than or equal to 11 times the thickness of the third portion 205c in the direction perpendicular to the main surface of the substrate 201. The height difference between the third portion 205c and the eighth portion 205d in the direction perpendicular to the main surface of the substrate 201 is greater than or equal to 8 times the thickness of the third portion 205c in the direction perpendicular to the main surface of the substrate 201, and less than or equal to 11 times the thickness of the third portion 205c in the direction perpendicular to the main surface of the substrate 201.

[0120] For example, such as Figure 4 As shown, the display substrate 200 further includes a second auxiliary layer 207, which is disposed at least on the side of the second color quantum dot layer 204 away from the substrate 201. Figure 4In this structure, a portion of the second auxiliary layer 207 is disposed on the side of the first auxiliary layer 205 corresponding to the first color quantum dot layer 203 away from the substrate 201, and on the side of the second color quantum dot layer 204 away from the substrate 201. Another portion of the second auxiliary layer 207 is disposed on the side of the third color quantum dot layer 206 close to the substrate 201, and is located between the third color quantum dot layer 206 and the first auxiliary layer 205 corresponding to the third color quantum dot layer 206.

[0121] For example, in one example, the first auxiliary layer 205 and the second auxiliary layer 207 are made of the same material, which can reduce the types of materials used, and the first auxiliary layer 205 and the second auxiliary layer 207 can be formed using the same equipment and process conditions, thereby saving equipment costs.

[0122] For example, in another example, the first auxiliary layer 205 and the second auxiliary layer 207 are made of different materials, so as to avoid color mixing problems to the greatest extent possible according to the needs of the process, thereby improving the color gamut of the electroluminescent device formed subsequently.

[0123] For example, such as Figure 4As shown, the second auxiliary layer 207 includes at least a fourth portion 207a, a fifth portion 207b, and a sixth portion 207c spaced apart from each other. The fourth portion 207a is disposed on the side of the first portion 205a of the first auxiliary layer 205 away from the substrate 201, and is at least partially in contact with the first portion 205a. That is, in the first sub-pixel region 2022a, the first portion 205a of the first auxiliary layer 205 and the fourth portion 207a of the second auxiliary layer 207 are at least partially in contact and surface-fitted. It should be noted that when there is no second color quantum dot material in the first sub-pixel region 2022a, the first portion 205a and the fourth portion 207a are in direct contact and surface-fitted; when there is some second color quantum dot material in the first sub-pixel region 2022a, the first portion 205a and the fourth portion 207a may be in partial contact, but the remaining second color quantum dot material may be distributed in a dotted pattern rather than distributed across the entire surface. The fifth portion 207b is disposed on the side of the second color quantum dot layer 204 away from the substrate 201, i.e., in the second sub-pixel region 2022b. The second color quantum dot layer 204 is sandwiched between the second portion 205b of the first auxiliary layer 205 and the fifth portion 207b of the second auxiliary layer 207. The sixth portion 207c is disposed on the side of the third color quantum dot layer 206 near the substrate 201, i.e., in the third sub-pixel region 2022c. The side of the third color quantum dot layer 206 near the substrate 201 has an eighth portion 205d of the first auxiliary layer 205 and a sixth portion 207c of the second auxiliary layer 207 stacked together, and the eighth portion 205d is on the side of the sixth portion 207c near the substrate 201.

[0124] For example, such as Figure 4 As shown, the second auxiliary layer 207 also includes a seventh portion 207d that is spaced apart from the fourth portion 207a, the fifth portion 207b, and the sixth portion 207c. The seventh portion 207d is disposed on the side of the third portion 205c away from the substrate and is at least partially in contact with the third portion 205c. It should be noted that when there is no second color quantum dot material on the pixel defining layer 202, the seventh portion 207d and the third portion 205c are in direct contact and surface-fitted; when there is some second color quantum dot material on the pixel defining layer 202, the seventh portion 207d and the third portion 205c can be partially in contact. That is, the third portion 205c of the first auxiliary layer 205 and the seventh portion 207d of the second auxiliary layer 207 are stacked on the pixel defining layer 202 except for the opening 2021.

[0125] It should be noted that when the formation order of the first color quantum dot layer 203, the second color quantum dot layer 204 and the third color quantum dot layer 206 changes, the structure of the first auxiliary layer 205 will also change.

[0126] For example, when a second color quantum dot layer 204 is formed first, then a first color quantum dot layer 203 is formed, and finally a third color quantum dot layer 206 is formed, in the second sub-pixel region 2022b, a first auxiliary layer 205 and a second auxiliary layer 207 are sequentially stacked on the side of the second color quantum dot layer 204 away from the substrate 201; in the first sub-pixel region 2022a, the first color quantum dot layer 203 is sandwiched between the first auxiliary layer 205 and the second auxiliary layer 207, that is, the first auxiliary layer 205 is disposed on the side of the first color quantum dot layer 203 near the substrate 201, and the second auxiliary layer 207 is disposed on the side of the first color quantum dot layer 203 away from the substrate 201; in the third sub-pixel region 2022c, the first auxiliary layer 205 and the second auxiliary layer 207 are sequentially stacked on the side of the third color quantum dot layer 206 near the substrate 201.

[0127] For example, when a third color quantum dot layer 206 is formed first, followed by a first color quantum dot layer 203, and finally a second color quantum dot layer 204, in the third sub-pixel region 2022c, a first auxiliary layer 205 and a second auxiliary layer 207 are sequentially stacked on the side of the third color quantum dot layer 206 away from the substrate 201; in the first sub-pixel region 2022a, the first color quantum dot layer 203 is sandwiched between the first auxiliary layer 205 and the second auxiliary layer 207, that is, the first auxiliary layer 205 is disposed on the side of the first color quantum dot layer 203 closer to the substrate 201, and the second auxiliary layer 207 is disposed on the side of the first color quantum dot layer 203 away from the substrate 201; in the second sub-pixel region 2022b, the first auxiliary layer 205 and the second auxiliary layer 207 are sequentially stacked on the side of the second color quantum dot layer 204 closer to the substrate 201.

[0128] For example, in one example, the materials of the first auxiliary layer 205 and the second auxiliary layer 207 both include at least one of electron transport oxide and hole transport oxide. For example, the materials of the first auxiliary layer 205 and the second auxiliary layer 207 may both include electron transport oxide, or the materials of the first auxiliary layer 205 and the second auxiliary layer 207 may both include hole transport oxide. Alternatively, the material of the first auxiliary layer 205 may include electron transport oxide and the material of the second auxiliary layer 207 may include hole transport oxide. The embodiments of this disclosure do not limit this.

[0129] For example, the first auxiliary layer is made of an electron transport oxide, the second auxiliary layer is made of a hole transport oxide, and at least a portion of the first auxiliary layer is in contact with the first color quantum dot layer, and at least a portion of the second auxiliary layer is in contact with the third color quantum dot layer. For example, the first color quantum dot layer is a blue quantum dot layer, the second color quantum dot layer is one of a red quantum dot layer and a green quantum dot layer, and the third color quantum dot layer is the other of a green quantum dot layer and a red quantum dot layer. Compared to the case where both the first and second auxiliary layers are hole transport oxides or both are electron transport oxides, the electron transport effect is better when the first auxiliary layer is made of an electron transport oxide and the second auxiliary layer is made of a hole transport oxide. If both the first and second auxiliary layers are made of hole transport oxides, or both are made of electron transport oxides, the thickness of the stacked first and second auxiliary layers may be too large, which may lead to excessive electron or hole blocking, thus affecting the performance of the final electroluminescent device.

[0130] For example, the material of the first auxiliary layer includes an electron transport oxide, the material of the second auxiliary layer includes a hole transport oxide, and at least a portion of the first auxiliary layer is in contact with the first color quantum dot layer, and at least a portion of the second auxiliary layer is in contact with the third color quantum dot layer / third color quantum dot layer. The beneficial effects of this include: for the first sub-pixel prepared first, for example, a blue sub-pixel, only one layer of hole transport oxide is deposited after the first color quantum dot layer, while the second layer of electron transport oxide can directly serve as an electron transport layer, preventing the hole transport interface layer from being too thick and affecting hole injection into the first color quantum dot; for the second sub-pixel prepared second, for example, a green sub-pixel, the interface layer of the second color quantum dot layer has the same function as the first and second auxiliary layers on both sides; for the third sub-pixel prepared last, for example, a red sub-pixel, its electron transport interface layer has the same function as the electron transport oxide below, with only one layer of hole transport interface layer, and the thickness of the second auxiliary layer will not prevent hole injection into the third color quantum dot layer.

[0131] Considering the energy level differences among red, green, and blue quantum dots, red and green sub-pixels are generally multi-electron devices, while blue sub-pixels are generally multi-hole devices. Therefore, the first sub-pixel to be fabricated is a blue sub-pixel. The material of the first auxiliary layer includes electron transport oxide. The green and red sub-pixels can be fabricated as the second or third sub-pixels, respectively. The material of the second auxiliary layer includes hole transport oxide. This allows the electron transport oxide in the blue sub-pixel to block holes, and the hole transport oxide in the third sub-pixel to block electrons, thereby balancing the charge carriers and improving the carrier injection efficiency.

[0132] For example, in one example, the materials of the first auxiliary layer 205 and the second auxiliary layer 207 both include electron transport oxides such as zinc oxide and tin oxide, or both include hole transport oxides such as gallium nitride, aluminum nitride, molybdenum oxide, nickel oxide, zirconium oxide, and vanadium oxide, or zinc oxide doped with magnesium, tin, gallium, indium, zirconium, hafnium, yttrium, lithium, or aluminum, or tin oxide doped with magnesium, tin, gallium, indium, zirconium, hafnium, yttrium, lithium, or aluminum. The embodiments of this disclosure do not limit this.

[0133] For example, in one example, the general formulas of the materials of the first auxiliary layer 205 and the second auxiliary layer 207 both include At least one of the following, where A is at least one of -SH, -COOH, and -NH2; M is... X is less than or equal to 6; P includes... At least one of them.

[0134] For example, in one example, the materials of both the first auxiliary layer 205 and the second auxiliary layer 207 include At least one of them.

[0135] For example, in one instance, the materials of both the first auxiliary layer 205 and the second auxiliary layer 207 include a first group, a second group, and a third group, wherein the first group includes -C(CF3)3, -C n F( 2n+1 )or The second group includes a mercapto, carboxyl, or amino group; the third group includes at least one of an alkyl chain, an aromatic ring, an alkenyl, an alkynyl, an aromatic amino group, an epoxy group, and an ester group.

[0136] For example, Figure 5 This is a cross-sectional structural diagram of at least one embodiment of the present disclosure, showing a first auxiliary layer as a double-layer structure with stacked layers, as shown below. Figure 5 As shown, the first auxiliary layer 205 includes a stacked first layer structure 2051 and a second layer structure 2052. The first layer structure 2051 is located on the side of the second layer structure 2052 closest to the substrate 201. The material of the first layer structure 2051 includes at least one of electron transport oxide and hole transport oxide.

[0137] For example, the material of the first layer structure includes at least one of zinc oxide, tin oxide, gallium nitride, aluminum nitride, molybdenum oxide, nickel oxide, zirconium oxide, vanadium oxide, zinc oxide doped with magnesium, tin, gallium, indium, zirconium, hafnium, yttrium, lithium or aluminum, and tin oxide doped with magnesium, tin, gallium, indium, zirconium, hafnium, yttrium, lithium or aluminum.

[0138] For example, the general formula for the second-layer structure 2052 includes: Where A is -(CH2)nCH3, n is less than or equal to 4; M is -(CH2)x, x is less than or equal to 6; P includes At least one of them.

[0139] For example, the materials and formation order of the first layer structure 2051 and the second layer structure 2052 cannot be changed. The organic material in the second layer structure 2052 can reduce lattice defects and achieve the effect of insulation and passivation.

[0140] For example, Figure 6 This is a cross-sectional structural diagram of at least one embodiment of the present disclosure, showing a double-layer structure in which the second auxiliary layer is stacked. Figure 6 As shown, the second auxiliary layer 207 includes a stacked third layer structure 2071 and a fourth layer structure 2072. The third layer structure 2071 is located on the side of the fourth layer structure 2072 closer to the substrate 201. The material of the third layer structure 2071 includes at least one of electron transport oxide and hole transport oxide.

[0141] For example, the material of the third layer structure 2071 includes at least one of zinc oxide, tin oxide, gallium nitride, aluminum nitride, molybdenum oxide, nickel oxide, zirconium oxide, vanadium oxide, zinc oxide doped with magnesium, tin, gallium, indium, zirconium, hafnium, yttrium, lithium or aluminum, and tin oxide doped with magnesium, tin, gallium, indium, zirconium, hafnium, yttrium, lithium or aluminum.

[0142] For example, the general formula for the fourth layer structure 2072 includes: Where A is -(CH2)nCH3, n is less than or equal to 4; M is -(CH2)x, x is less than or equal to 6; P includes At least one of them.

[0143] For example, the material and formation order of the third layer structure 2071 in the fourth layer structure 2072 cannot be changed. The organic material in the fourth layer structure 2072 can reduce lattice defects and achieve the effect of insulation and passivation.

[0144] For example, when zinc oxide is formed using the sol-gel method and then used as the material for the first auxiliary layer, a significant number of quantum dots become difficult to remove. However, when zinc oxide formed by sputtering is used as the first auxiliary layer, compared to zinc oxide formed by the sol-gel method, fewer quantum dots remain on the sputtered zinc oxide. Furthermore, sputtered zinc oxide has the following structural characteristics: because it does not contain organic materials as raw materials, it has a low surface roughness; and because it does not contain organic materials, and because it is non-nanoparticle, the bonding force between the quantum dots and the smooth surface of the sputtered zinc oxide is weak, making it easy to wash away the quantum dots without leaving any residue.

[0145] For example, Figure 7 This is a schematic cross-sectional view of another display substrate provided in at least one embodiment of the present disclosure. Figure 7 The illustrated embodiments and Figure 4 The difference in the illustrated embodiment is that the first auxiliary layer 205 is patterned, and the first auxiliary layer 205 is not disposed on the surface of the pixel defining layer 202 away from the substrate 201, such as... Figure 7 As shown, the first auxiliary layer 205 includes at least a first portion 205a, a second portion 205b, and an eighth portion 205d spaced apart from each other. The first portion 205a is disposed on the side of the first color quantum dot layer 203 away from the substrate 201, the second portion 205b is disposed on the side of the second color quantum dot layer 204 close to the substrate 201, and the eighth portion 205d is disposed on the side of the third color quantum dot layer 206 close to the substrate 201. Since there is a step difference between the portion of the pixel defining layer 202 other than the opening 2021 and the opening 2021, the first portion 205a, the second portion 205b, and the eighth portion 205d are in a disconnected state during the formation process.

[0146] For example, such as Figure 7 As shown, the display substrate 200 also includes a second auxiliary layer 207, which is connected to... Figure 4 The difference in the illustrated embodiment lies in that the second auxiliary layer 207 has been patterned. The second auxiliary layer 207 is not disposed on the surface of the pixel defining layer 202 away from the substrate 201. Instead, the second auxiliary layer 207 is disposed at least on the side of the second color quantum dot layer 204 away from the substrate 201. Figure 7In this structure, a portion of the second auxiliary layer 207 is disposed on the side of the first auxiliary layer 205 corresponding to the first color quantum dot layer 203 away from the substrate 201, and on the side of the second color quantum dot layer 204 away from the substrate 201. Another portion of the second auxiliary layer 207 is disposed on the side of the third color quantum dot layer 206 close to the substrate 201, and is located between the third color quantum dot layer 206 and the first auxiliary layer 205 corresponding to the third color quantum dot layer 206.

[0147] For example, in one example, the first auxiliary layer 205 and the second auxiliary layer 207 are made of the same material, which can reduce the types of materials used, and the first auxiliary layer 205 and the second auxiliary layer 207 can be formed using the same equipment and process conditions, thereby saving equipment costs.

[0148] For example, in another example, the first auxiliary layer 205 and the second auxiliary layer 207 are made of different materials, so as to avoid color mixing problems to the greatest extent possible according to the needs of the process, thereby improving the color gamut of the electroluminescent device formed subsequently.

[0149] For example, such as Figure 7As shown, the second auxiliary layer 207 includes at least a fourth portion 207a, a fifth portion 207b, and a sixth portion 207c spaced apart from each other. The fourth portion 207a is disposed on the side of the first portion 205a of the first auxiliary layer 205 away from the substrate 201, and is at least partially in contact with the first portion 205a. That is, in the first sub-pixel region 2022a, the first portion 205a of the first auxiliary layer 205 and the fourth portion 207a of the second auxiliary layer 207 are at least partially in direct contact and surface-fitted. It should be noted that when there is no second color quantum dot material in the first sub-pixel region 2022a, the first portion 205a and the fourth portion 207a are in direct contact and surface-fitted; when there is some second color quantum dot material in the first sub-pixel region 2022a, the first portion 205a and the fourth portion 207a may be in partial contact, but the remaining second color quantum dot material may be distributed in a dotted pattern rather than distributed across the entire surface. The fifth portion 207b is disposed on the side of the second color quantum dot layer 204 away from the substrate 201, i.e., in the second sub-pixel region 2022b. The second color quantum dot layer 204 is sandwiched between the second portion 205b of the first auxiliary layer 205 and the fifth portion 207b of the second auxiliary layer 207. The sixth portion 207c is disposed on the side of the third color quantum dot layer 206 near the substrate 201, i.e., in the third sub-pixel region 2022c. The side of the third color quantum dot layer 206 near the substrate 201 has an eighth portion 205d of the first auxiliary layer 205 and a sixth portion 207c of the second auxiliary layer 207 stacked together, and the eighth portion 205d is on the side of the sixth portion 207c near the substrate 201.

[0150] It should be noted that when the formation order of the first color quantum dot layer 203, the second color quantum dot layer 204 and the third color quantum dot layer 206 changes, the structure of the first auxiliary layer 205 will also change.

[0151] For example, when a second color quantum dot layer 204 is formed first, then a first color quantum dot layer 203 is formed, and finally a third color quantum dot layer 206 is formed, in the second sub-pixel region 2022b, a first auxiliary layer 205 and a second auxiliary layer 207 are sequentially stacked on the side of the second color quantum dot layer 204 away from the substrate 201; in the first sub-pixel region 2022a, the first color quantum dot layer 203 is sandwiched between the first auxiliary layer 205 and the second auxiliary layer 207, that is, the first auxiliary layer 205 is disposed on the side of the first color quantum dot layer 203 near the substrate 201, and the second auxiliary layer 207 is disposed on the side of the first color quantum dot layer 203 away from the substrate 201; in the third sub-pixel region 2022c, the first auxiliary layer 205 and the second auxiliary layer 207 are sequentially stacked on the side of the third color quantum dot layer 206 near the substrate 201.

[0152] For example, when a third color quantum dot layer 206 is formed first, followed by a first color quantum dot layer 203, and finally a second color quantum dot layer 204, in the third sub-pixel region 2022c, a first auxiliary layer 205 and a second auxiliary layer 207 are sequentially stacked on the side of the third color quantum dot layer 206 away from the substrate 201; in the first sub-pixel region 2022a, the first color quantum dot layer 203 is sandwiched between the first auxiliary layer 205 and the second auxiliary layer 207, that is, the first auxiliary layer 205 is disposed on the side of the first color quantum dot layer 203 closer to the substrate 201, and the second auxiliary layer 207 is disposed on the side of the first color quantum dot layer 203 away from the substrate 201; in the second sub-pixel region 2022b, the first auxiliary layer 205 and the second auxiliary layer 207 are sequentially stacked on the side of the second color quantum dot layer 204 closer to the substrate 201.

[0153] For example, Figure 8 This is a schematic cross-sectional view of an electroluminescent device provided in at least one embodiment of the present disclosure, as shown below. Figure 8As shown, the electroluminescent device 300 includes the display substrate 200 in any of the above embodiments, and the electroluminescent device 300 further includes a first electrode 208 and a first functional layer 209 stacked on the substrate 201. The first electrode 208 is disposed on the side of the first functional layer 209 near the substrate 201. The first functional layer 209 and the first electrode 208 are both stacked in a plurality of sub-pixel regions 2022. In the first sub-pixel region 2022a, the stacked first functional layer 209 and the first electrode 208 are between the first color quantum dot layer 203 and the substrate 201; in the second sub-pixel region 2022b, the stacked first functional layer 209 and the first electrode 208 are between the second color quantum dot layer 204 and the substrate 201; and in the third sub-pixel region 2022c, the stacked first functional layer 209 and the first electrode 208 are between the third color quantum dot layer 206 and the substrate 201.

[0154] For example, such as Figure 8 As shown, the electroluminescent device 300 further includes a second functional layer 210 and a third functional layer 211 disposed in multiple sub-pixel regions 2022 and on the side of the first color quantum dot layer 203, the second color quantum dot layer 204, and the third color quantum dot layer 206 away from the substrate 201. In different sub-pixel regions 2022, the stacked second functional layer 210 and the third functional layer 211 are spaced apart from each other. The entire surface of the second electrode 212 is disposed on the side of the third functional layer 211 away from the substrate 201, and the third functional layer 211 is on the side of the second functional layer 210 away from the substrate 201.

[0155] For example, in one example, the first functional layer 209 is an electron transport layer, the second functional layer 210 is a hole transport layer, and the third functional layer 211 is a hole injection layer.

[0156] For example, the material of the hole transport layer includes, but is not limited to, any one of N,N'-bis(1-naphthyl)-N,N'-diphenyl-1,1'-diphenyl-4,4'-diamine (NPB), 4,4',4”-tris(N-3-methylphenyl-N-phenylamino)triphenylamine (m-MTDATA), and 4,4-2-[N-(4-carbazolephenyl)-N-phenylamino]biphenyl (CPB).

[0157] For example, the hole injection layer can be a metal oxide (MeO), such as MoO3, or a p-type doped MeO (metal oxide)-TPD (N,N'10-bis(3-methylphenyl)-N,N'–diphenyl-1,1'–diphenyl-4,4'–diamine):F4TCNQ (N,N,N',N'-tetramethoxyphenyl)-p-diaminobiphenyl:2,3,5,6-tetrafluoro-7,7',8,8'-tetracyanodimethylp-benzoquinone) or m-MTDATA:F4TCNQ (4,4',4”-tris(N-3-methylphenyl-N-phenylamino)triphenylamine:2,3,5,6-tetrafluoro-7,7',8,8'-tetracyanodimethylp-benzoquinone), etc.

[0158] For example, in one instance, the electron transport layer may include a first inorganic nanoparticle or a first inorganic layer. The first inorganic nanoparticle may be, for example, an oxide nanoparticle, and may be, for example, a metal oxide nanoparticle.

[0159] For example, the first inorganic nanoparticle may be a two-dimensional or three-dimensional nanoparticle having an average particle diameter of less than or equal to about 10 nm, within the range of about 8 nm, less than or equal to about 7 nm, less than or equal to about 5 nm, less than or equal to about 4 nm, or less than or equal to about 3.5 nm, or within the range of about 1 nm to about 10 nm, about 1 nm to about 9 nm, about 1 nm to about 8 nm, about 1 nm to about 7 nm, about 1 nm to about 5 nm, about 1 nm to about 4 nm, or about 1 nm to about 3.5 nm.

[0160] For example, the first inorganic nanoparticle may be a metal oxide nanoparticle, which includes at least one of the following: zinc (Zn), magnesium (Mg), cobalt (Co), nickel (Ni), gallium (Ga), aluminum (Al), calcium (Ca), zirconium (Zr), tungsten (W), lithium (Li), titanium (Ti), tantalum (Ta), tin (Sn), hafnium (Hf), and barium (Ba).

[0161] As an example, the first inorganic nanoparticle may include metal oxide nanoparticles containing zinc (Zn), and may also include metal oxide nanoparticles represented by Zn1-xQxO (0≤x<0.5). Here, Q is at least one metal other than Zn, such as magnesium (Mg), cobalt (Co), nickel (Ni), gallium (Ga), aluminum (Al), calcium (Ca), zirconium (Zr), tungsten (W), lithium (Li), titanium (Ti), tantalum (Ta), tin (Sn), hafnium (Hf), silicon (Si), barium (Ba), or combinations thereof.

[0162] For example, Q may include magnesium (Mg).

[0163] For example, x can be in the range of 0.01≤x≤0.3, for example, 0.01≤x≤0.2.

[0164] For example, the material of the first inorganic layer is a metal oxide, which includes at least one of the following: zinc (Zn), magnesium (Mg), cobalt (Co), nickel (Ni), gallium (Ga), aluminum (Al), calcium (Ca), zirconium (Zr), tungsten (W), lithium (Li), titanium (Ti), tantalum (Ta), tin (Sn), hafnium (Hf), and barium (Ba).

[0165] For example, in one instance, the material of the electron transport layer includes 4,7-diphenyl-1,10-o-phenanthroline (BPhen).

[0166] The materials used are any one of 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene (TPBI) and n-doped electron transport materials, but are not limited thereto. Examples of n-doped electron transport materials include, for example, 2,9-dimethyl-4,7-biphenyl-1,10-o-diazaphenanthroline (BCP):Li₂CO₃, 8-hydroxyquinoline aluminum (Alq₃):Mg, TPBI:Li, etc., but the embodiments disclosed herein are not limited thereto.

[0167] For example, an electron injection layer may also be disposed between the first functional layer 209 and the substrate 201. The materials of the electron injection layer include: lithium oxide (Li2O), cesium oxide (Cs2O), sodium oxide (Na2O), lithium carbonate (Li2CO3), cesium carbonate (Cs2CO3), or sodium carbonate (Na2CO3), lithium fluoride (LiF), cesium fluoride (CsF), sodium fluoride (NaF), calcium fluoride (CaF2), aluminum 8-hydroxyquinoline (Alq3), lithium 8-hydroxyquinoline (Liq), gallium 8-hydroxyquinoline, bis[2-(2-hydroxyphenyl-1)-pyridine]beryllium, and 2-(4-diphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (PBD).

[0168] For example, the material of the first electrode can be a transparent conductive material, including indium tin oxide (ITO), indium zinc oxide (IZO), indium gallium oxide (IGO), zinc gallium oxide (GZO), zinc oxide (ZnO), indium oxide (In2O3), zinc aluminum oxide (AZO), and carbon nanotubes, etc.

[0169] For example, the material of the second electrode includes magnesium, aluminum, lithium single metal, or magnesium-aluminum alloy (MgAl), lithium-aluminum alloy (LiAl), etc.

[0170] For example, the first electrode is the anode and the second electrode is the cathode.

[0171] It should be noted that the materials and structures of the first and second electrodes described above are only one example in the embodiments of this disclosure. The first and second electrodes can also be made of other materials. Depending on the materials of the first and second electrodes, they can be divided into single-sided light-emitting quantum dot devices and double-sided light-emitting quantum dot devices. When the material of one of the anode and cathode electrodes is opaque or semi-transparent, it is a single-sided light-emitting quantum dot device. When the materials of the anode and cathode are both transparent and / or semi-transparent, it is a double-sided light-emitting quantum dot device.

[0172] Depending on the requirements, the materials of the first electrode and the second electrode can be selected to be suitable for top-emitting, bottom-emitting, and double-sided-emitting types, respectively. The embodiments of this disclosure do not limit the selection of materials for the first electrode and the second electrode.

[0173] For example, in Figure 8 The relevant features of the first color quantum dot layer 203, the second color quantum dot layer 204, the third color quantum dot layer 206, the first auxiliary layer 205, and the second auxiliary layer 207 can be found in the relevant descriptions above, and will not be repeated here.

[0174] For example, Figure 9 A schematic cross-sectional view of another electroluminescent device provided in at least one embodiment of this disclosure, as shown below. Figure 9 As shown, the electroluminescent device 300 includes the display substrate 200 in any of the above embodiments, and the electroluminescent device 300 further includes: a first electrode 208 and a first functional layer 209 stacked on a substrate 201. The first electrode 208 is disposed on the entire surface of the substrate 201, and the first functional layer 209 is disposed on the side of the first electrode 208 away from the substrate 201. The first functional layer 209 is disposed in a plurality of sub-pixel regions 2022. In the first sub-pixel region 2022a, the first functional layer 209 is between the first color quantum dot layer 203 and the substrate 201; in the second sub-pixel region 2022b, the first functional layer 209 is between the second color quantum dot layer 204 and the substrate 201; and in the third sub-pixel region 2022c, the first functional layer 209 is between the third color quantum dot layer 206 and the substrate 201.

[0175] For example, such as Figure 9As shown, the electroluminescent device 300 further includes: a second functional layer 210, a third functional layer 211, and a second electrode 212 disposed in a plurality of sub-pixel regions 2022 and on the side of the first color quantum dot layer 203, the second color quantum dot layer 204, and the third color quantum dot layer 206 away from the substrate 201. The third functional layer 211 is on the side of the second functional layer 210 away from the substrate 201, and the second electrode 212 is on the side of the third functional layer 211 away from the substrate 201. That is, the first electrode 208 is formed over the entire surface. The second electrodes 212 in the pixel area 2022 are spaced apart from each other, so that the first color quantum dot layer 203 in the first sub-pixel area 2022a can emit light of the first color, the second color quantum dot layer 204 in the second sub-pixel area 2022b can emit light of the second color, and the third color quantum dot layer 206 in the third sub-pixel area 2022c can emit light of the third color. The first color light, the second color light, and the third color light have different colors, so that the purity of the light emitted from each sub-pixel area 2022 is higher.

[0176] For example, in Figure 9 The relevant features of the first color quantum dot layer 203, the second color quantum dot layer 204, the third color quantum dot layer 206, the first auxiliary layer 205, and the second auxiliary layer 207 can be found in the relevant descriptions above, and will not be repeated here.

[0177] For example, in one example, the first functional layer 209 is an electron transport layer, the second functional layer 210 is a hole transport layer, and the third functional layer 211 is a hole injection layer. The materials for the electron transport layer, hole transport layer, hole injection layer, first electrode, and second electrode are not particularly limited; please refer to the above. Figure 8 Based on the relevant descriptions in the text, those skilled in the art can select materials according to the commonly used materials for the above-mentioned structures of quantum dot electroluminescent devices.

[0178] At least one embodiment of this disclosure also provides a method for fabricating an electroluminescent device. The method includes: providing a substrate; forming a pixel defining layer on the substrate, the pixel defining layer including a plurality of openings to form a plurality of sub-pixel regions spaced apart from each other, the plurality of sub-pixel regions including at least a first sub-pixel region and a second sub-pixel region; forming a first color quantum dot layer in the first sub-pixel region; forming a second color quantum dot layer in the second sub-pixel region. The method further includes: forming a first auxiliary layer after forming the first color quantum dot layer and before forming the second color quantum dot layer, the first auxiliary layer including at least a first portion and a second portion spaced apart from each other, the first portion being disposed on the side of the first color quantum dot layer away from the substrate; and the second portion being disposed on the side of the second color quantum dot layer close to the substrate.

[0179] For example, Figure 10 A flowchart illustrating the fabrication process of an electroluminescent device provided in at least one embodiment of this disclosure is shown below. Figure 10 As shown, the preparation method includes the following steps.

[0180] S11, Provide a substrate.

[0181] For example, the substrate may include a transparent insulating substrate such as a glass substrate or a flexible substrate. The material of the substrate may also be other suitable materials, and the embodiments disclosed herein do not limit this.

[0182] S12. A pixel defining layer is formed on a substrate. The pixel defining layer includes a plurality of openings to form a plurality of sub-pixel regions spaced apart from each other. The plurality of sub-pixel regions include at least a first sub-pixel region and a second sub-pixel region.

[0183] For example, the process of forming a pixel defining layer includes: depositing a pixel defining layer material on a substrate, then applying a photoresist material on the pixel defining layer material, exposing and developing the photoresist material using a mask to form a photoresist pattern, and then etching the pixel defining layer material using the photoresist pattern as a mask to form the pixel defining layer. The etched portion of the pixel defining layer material forms multiple openings, and multiple sub-pixel regions are formed at positions corresponding to the multiple openings. The multiple sub-pixel regions are spaced apart from each other, such that they include at least a first sub-pixel region and a second sub-pixel region that are spaced apart from each other.

[0184] S13. Form a first color quantum dot layer in the first sub-pixel region.

[0185] For example, forming a first color quantum dot layer in a first sub-pixel region may include: applying a material of the first color quantum dot layer to a plurality of sub-pixel regions to form a first color quantum dot film, and then performing a patterning process on the first color quantum dot film to form a first color quantum dot layer.

[0186] For example, the patterning process for the first color quantum dot film includes using a mask to block the non-exposed areas of the first color quantum dot film, such as blocking the second and third sub-pixel areas, exposing the area to be exposed (the first sub-pixel area) to crosslink the first color quantum dot material in the first sub-pixel area, completing the development process, and removing the second color quantum dot material in the second and third sub-pixel areas, thereby forming a patterned first color quantum dot layer.

[0187] For example, the first color quantum dot layer includes a material of the first color quantum dots. The thickener, coupling agent and accelerator included in the first color quantum dot layer can be found in the relevant descriptions above, and will not be repeated here.

[0188] S14, Form the first auxiliary layer.

[0189] For example, the first auxiliary layer has electron transport properties, and the connection between the first auxiliary layer and the uncrosslinked quantum dot material located thereon is weak, making the uncrosslinked quantum dot material easier to clean off. This can prevent the second color quantum dot material formed later from remaining on the first color quantum dot layer, thereby avoiding the problem of color mixing and improving the color gamut of the quantum dot electroluminescent device.

[0190] For example, the structure and materials of the first auxiliary layer can be found in the relevant descriptions above, and will not be repeated here.

[0191] S15, Form a second color quantum dot layer in the second sub-pixel region.

[0192] For example, forming a second color quantum dot layer in a second sub-pixel region may include: applying a material of the second color quantum dot layer to a plurality of sub-pixel regions to form a second color quantum dot film, and then performing a patterning process on the second color quantum dot film to form a second color quantum dot layer.

[0193] For example, the patterning process for the second color quantum dot film includes using a mask to block the non-exposed areas of the second color quantum dot film, such as blocking the first sub-pixel area and the third sub-pixel area, and exposing the area to be exposed (the second sub-pixel area) to crosslink the second color quantum dot material in the second sub-pixel area, and completing the development process, and removing the second color quantum dot material in the first sub-pixel area and the third sub-pixel area, thereby forming a patterned second color quantum dot layer.

[0194] For example, the second color quantum dot layer includes a material containing second color quantum dots. The thickeners, coupling agents, and promoters included in the second color quantum dot layer can be found in the relevant descriptions above, and will not be repeated here.

[0195] For example, in one instance, before forming the first color quantum dot layer, the method further includes: forming a first functional layer on a substrate, wherein the first functional layer and the first auxiliary layer are bonded together in the second sub-pixel region and the third sub-pixel region. That is, the first functional layer is formed first, followed by the formation of the first color quantum dot layer, then the formation of the first auxiliary layer, and subsequently the formation of the second color quantum dot layer and the third color quantum dot layer.

[0196] For example, the first functional layer is an electron transport layer, which can transport electrons. The material of the electron transport layer can be found in the relevant description above, and will not be repeated here.

[0197] For example, in one example, the first auxiliary layer and the first functional layer are made of the same material, such as zinc oxide. In the direction perpendicular to the main surface of the substrate, the thickness of the first functional layer is 4 to 5 times the thickness of the first auxiliary layer. For example, the thickness of the first auxiliary layer is 4, 4.2, 4.4, 4.6, 4.8, or 5 times that of the first functional layer.

[0198] For example, in one example, the thickness of the first color quantum dot layer is 4 to 5 times the thickness of the first auxiliary layer, such as 4, 4.2, 4.4, 4.6, 4.8, or 5 times the thickness of the first auxiliary layer.

[0199] For example, in one instance, the material of the first auxiliary layer includes at least one of electron transport oxide and hole transport oxide, and the first auxiliary layer is formed by magnetron sputtering.

[0200] For example, the material of the first auxiliary layer includes electron transport oxides such as zinc oxide and tin oxide, or includes gallium nitride, aluminum nitride, molybdenum oxide, nickel oxide, zirconium oxide, vanadium oxide, zinc oxide doped with magnesium, tin, gallium, indium, zirconium, hafnium, yttrium, lithium or aluminum, and tin oxide doped with magnesium, tin, gallium, indium, zirconium, hafnium, yttrium, lithium or aluminum. The embodiments of this disclosure do not limit this.

[0201] For example, after the development process, the interaction between the unexposed second color quantum dots and the first auxiliary layer (e.g., sputtered zinc oxide) is weak, and the second color quantum dots leave little residue on the sputtered zinc oxide, thereby resulting in less residue of the second color quantum dots in the first sub-pixel region.

[0202] For example, the first color quantum dot layer includes first color quantum dots, and forming the first auxiliary layer includes immersing a substrate on which the first color quantum dot layer is formed in a first solution, for example, for 5 to 30 minutes. The first solution includes a first group containing a perfluorinated terminus and a second group that can coordinate with the terminus of the first color quantum dots.

[0203] For example, in one example, the first group includes -C(CF3)3, -C n F( 2n+1 )or The second group includes a thiol, carboxyl, or amino group.

[0204] For example, in one example, the first solution also includes a third group connecting the first and second groups. This third group can be an electron-withdrawing group or an alkyl chain. For instance, an electron-withdrawing group is one that reduces the electron cloud density on the benzene ring when a substituent replaces a hydrogen atom; conversely, an electron-donating group is one that increases the electron cloud density on the benzene ring. Whether a group is electron-withdrawing or electron-donating depends on the sum of its inductive, conjugating, and hyperconjugating effects on the benzene ring. Choosing an electron-withdrawing group can reduce electron transport to some extent, prevent leakage, and facilitate carrier balance. When the second group contains photosensitive groups such as double bonds, triple bonds, epoxy bonds, or ester bonds, this ligand assumes the photosensitizing function of the quantum dot.

[0205] For example, in one instance, the electron-withdrawing group includes at least one of an aromatic ring, an alkenyl group, an alkynyl group, an aromatic amino group, an epoxy group, and an ester group.

[0206] For example, in one example, the general formula of the material of the first auxiliary layer includes At least one of the following, where A is at least one of -SH, -COOH, and -NH2; M is... X is less than or equal to 6; P includes... At least one of them.

[0207] For example, in one example, the material of the first auxiliary layer includes At least one of them.

[0208] For example, in one example, forming the first auxiliary layer includes forming a stacked first layer structure and a second layer structure, the first layer structure being on the side of the second layer structure closer to the substrate, and forming the first layer structure includes: applying at least one of an electron transport oxide and a hole transport oxide onto the substrate using magnetron sputtering; forming the second layer structure includes immersing the substrate with the first layer structure in a solution of a silane coupling agent, for example, for 5 to 30 minutes, the silane coupling agent solution including a first group containing a perfluorinated terminus, the first group including... At least one of them.

[0209] For example, the material of the first layer structure includes at least one of electron transport oxides and hole transport oxides. For example, it includes electron transport oxides such as zinc oxide and tin oxide, or hole transport oxides such as gallium nitride, aluminum nitride, molybdenum oxide, nickel oxide, zirconium oxide, and vanadium oxide, or zinc oxide doped with magnesium, tin, gallium, indium, zirconium, hafnium, yttrium, lithium, or aluminum, and at least one of tin oxide doped with magnesium, tin, gallium, indium, zirconium, hafnium, yttrium, lithium, or aluminum. The embodiments of this disclosure are not limited in this regard.

[0210] For example, the general formula for the material of this second layer structure includes: Where A is -(CH2)nCH3, n is less than or equal to 4; M is -(CH2)x, x is less than or equal to 6; P includes At least one of them.

[0211] For example, in one example, a second auxiliary layer is formed at least on the side of the second color quantum dot layer away from the substrate, and a third color quantum dot layer is formed on the side of the second auxiliary layer away from the substrate in the third sub-pixel region, wherein the materials of the first auxiliary layer and the second auxiliary layer are the same or different.

[0212] For example, the structure of the second auxiliary layer can be found in the relevant description above, and will not be repeated here.

[0213] For example, in one instance, the material of the second auxiliary layer includes at least one of electron transport oxide and hole transport oxide, and the second auxiliary layer is formed by magnetron sputtering.

[0214] For example, the material of the second auxiliary layer includes electronic transport materials such as zinc oxide and tin oxide, or hole transport materials such as gallium nitride, aluminum nitride, molybdenum oxide, nickel oxide, zirconium oxide, and vanadium oxide, zinc oxide doped with magnesium, tin, gallium, indium, zirconium, hafnium, yttrium, lithium, or aluminum, and tin oxide doped with magnesium, tin, gallium, indium, zirconium, hafnium, yttrium, lithium, or aluminum.

[0215] For example, the second color quantum dot layer includes second color quantum dots, and forming the second auxiliary layer includes immersing a substrate on which the first color quantum dot layer is formed in a second solution, the second solution including a third group containing a perfluorinated terminus and a fourth group that can coordinate with the terminus of the second color quantum dots.

[0216] For example, in one instance, the third group includes -C(CF3)3, -C n F( 2n+1 )or The fourth group includes a thiol, carboxyl, or amino group.

[0217] For example, in one example, the second solution further includes a fifth group connecting the third and fourth groups, the fifth group comprising an electron-withdrawing group or an alkyl chain. For instance, the general formula of the material of the second auxiliary layer formed from the second solution includes... At least one of the following, where A is at least one of -SH, -COOH, and -NH2; M is... X is less than or equal to 6; P includes... At least one of them.

[0218] For example, in one example, forming the second auxiliary layer includes forming a stacked third layer structure and a fourth layer structure, the third layer structure being on the side of the fourth layer structure closer to the substrate, and forming the third layer structure includes applying at least one of an electron transport oxide and a hole transport oxide onto the substrate using magnetron sputtering.

[0219] For example, forming a fourth layer structure includes immersing a substrate having a third layer structure formed thereon in a solution of a silane coupling agent, the solution of which includes a third group containing a perfluorinated terminus, for example, the third group includes... At least one of them.

[0220] For example, in one example, the material of the third layer structure includes electron transport oxides such as zinc oxide and tin oxide, or hole transport oxides such as gallium nitride, aluminum nitride, molybdenum oxide, nickel oxide, zirconium oxide, and vanadium oxide, or zinc oxide doped with magnesium, tin, gallium, indium, zirconium, hafnium, yttrium, lithium, or aluminum, or tin oxide doped with magnesium, tin, gallium, indium, zirconium, hafnium, yttrium, lithium, or aluminum.

[0221] For example, the first auxiliary layer and the second auxiliary layer are made of different materials; the first auxiliary layer is made of an electron transport oxide, and the second auxiliary layer is made of a hole transport oxide.

[0222] For example, Figure 11 A flowchart illustrating the fabrication process of another electroluminescent device provided in at least one embodiment of this disclosure is shown below. Figure 11 As shown, the preparation method includes the following steps.

[0223] S21, Provide a substrate.

[0224] For example, the material of the substrate can be found in the relevant description above, and the embodiments disclosed herein are not limited thereto.

[0225] S22. A pixel defining layer is formed on a substrate. The pixel defining layer includes a plurality of openings to form a plurality of sub-pixel regions spaced apart from each other. The plurality of sub-pixel regions include at least a first sub-pixel region, a second sub-pixel region, and a third sub-pixel region.

[0226] For example, the process of forming a pixel boundary layer can be found in the above-mentioned... Figure 9 The relevant descriptions will not be repeated here.

[0227] S23. The first functional layer is formed in the first sub-pixel region, the second sub-pixel region and the third sub-pixel region respectively.

[0228] For example, the first functional layer is an electron transport layer. For example, the electron transport layer can be formed of a metal oxide; specifically, the material constituting the electron transport layer can include at least one of zinc oxide, nickel oxide, and titanium oxide. For example, the material of the electron transport layer can also include any one of 4,7-diphenyl-1,10-o-diaphenanthrene (BPhen), 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene (TPBI), and n-doped electron transport materials, but is not limited thereto. n-doped electron transport materials include, for example, 2,9-dimethyl-4,7-biphenyl-1,10-o-diaphenanthrene (BCP):Li₂CO₃, 8-hydroxyquinoline aluminum (Alq₃):Mg, TPBI:Li, etc., but the embodiments of this disclosure are not limited thereto.

[0229] For example, the first functional layer can be formed by spin coating and annealing, or it can be formed on the substrate by vapor deposition.

[0230] It should be noted that before forming the first functional layer, an electron injection layer can also be formed on the substrate. The material of the electron injection layer can be found in the relevant description above, and will not be repeated here.

[0231] S24. Form a first color quantum dot layer in the first sub-pixel region.

[0232] For example, forming a first color quantum dot layer in a first sub-pixel region may include: applying a material of the first color quantum dot layer to a plurality of sub-pixel regions to form a first color quantum dot film, and then performing a patterning process on the first color quantum dot film to form a first color quantum dot layer.

[0233] For example, the patterning process for the first color quantum dot film includes using a mask to block the non-exposed areas of the first color quantum dot film, such as blocking the second and third sub-pixel areas, exposing the area to be exposed (the first sub-pixel area) to crosslink the first color quantum dot material in the first sub-pixel area, completing the development process, and removing the second color quantum dot material in the second and third sub-pixel areas, thereby forming a patterned first color quantum dot layer.

[0234] For example, the first color quantum dot layer includes a material of the first color quantum dots. The thickener, coupling agent and accelerator included in the first color quantum dot layer can be found in the relevant descriptions above, and will not be repeated here.

[0235] For example, a second color quantum dot layer and a third color quantum dot layer can be subsequently formed in the second sub-pixel region and the third sub-pixel region, respectively.

[0236] S25, Form the first auxiliary layer.

[0237] For example, the first auxiliary layer has electron transport properties, and the connection between the first auxiliary layer and the uncrosslinked quantum dot material located thereon is weak, making the uncrosslinked quantum dot material easier to clean off. This avoids the second color quantum dot material formed later remaining on the first color quantum dot layer, thereby avoiding the problem of color mixing and improving the color gamut of the quantum dot electroluminescent device.

[0238] For example, the first auxiliary layer is formed as a single layer, and is formed in the first sub-pixel region, the second sub-pixel region and the third sub-pixel region, and is formed on the side of the pixel defining layer away from the substrate.

[0239] For example, the structure and materials of the first auxiliary layer can be found in the relevant descriptions above, and will not be repeated here.

[0240] S26. A second color quantum dot layer is formed in the second sub-pixel region.

[0241] For example, forming a second color quantum dot layer in a second sub-pixel region may include: applying a material of the second color quantum dot layer to a plurality of sub-pixel regions to form a second color quantum dot film, and then performing a patterning process on the second color quantum dot film to form a second color quantum dot layer.

[0242] For example, the patterning process for the second color quantum dot film includes using a mask to block the non-exposed areas of the second color quantum dot film, such as blocking the first sub-pixel area and the third sub-pixel area, and exposing the area to be exposed (the second sub-pixel area) to crosslink the second color quantum dot material in the second sub-pixel area, and completing the development process, and removing the second color quantum dot material in the first sub-pixel area and the third sub-pixel area, thereby forming a patterned second color quantum dot layer.

[0243] For example, the second color quantum dot layer includes a material containing second color quantum dots. The thickeners, coupling agents, and promoters included in the second color quantum dot layer can be found in the relevant descriptions above, and will not be repeated here.

[0244] S27, Form the second auxiliary layer.

[0245] For example, the weak connection between the second auxiliary layer and the uncrosslinked quantum dot material on it makes the uncrosslinked quantum dot material easier to clean off, thereby preventing the third color quantum dot material formed later from remaining on the second color quantum dot layer and the first color quantum dot layer, thus avoiding the problem of color mixing and improving the color gamut of the quantum dot electroluminescent device.

[0246] For example, the second auxiliary layer is formed as a single layer, and is formed in the first sub-pixel region, the second sub-pixel region and the third sub-pixel region, and is formed on the side of the pixel defining layer away from the substrate, that is, on the side of the pixel defining layer away from the substrate. The first auxiliary layer and the second auxiliary layer are stacked sequentially.

[0247] For example, the structure and materials of the second auxiliary layer can be found in the relevant descriptions above, and will not be repeated here.

[0248] S28. A third color quantum dot layer is formed in the third sub-pixel region.

[0249] For example, forming a third color quantum dot layer in a third sub-pixel region may include: applying a material of the third color quantum dot layer to multiple sub-pixel regions to form a third color quantum dot film, and then performing a patterning process on the third color quantum dot film to form a third color quantum dot layer.

[0250] For example, the patterning process for the third color quantum dot film includes using a mask to block the non-exposed areas of the third color quantum dot film, such as blocking the first sub-pixel area and the second sub-pixel area, and exposing the area to be exposed (the third sub-pixel area) to crosslink the third color quantum dot material in the third sub-pixel area, and completing the development process, and removing the third color quantum dot material in the first sub-pixel area and the second sub-pixel area, thereby forming a patterned third color quantum dot layer.

[0251] For example, the third color quantum dot layer includes a material of third color quantum dots. The thickeners, coupling agents and promoters included in the third color quantum dot layer can be found in the relevant descriptions above, and will not be repeated here.

[0252] S29. A second functional layer and a third functional layer are sequentially formed on the side of the first color quantum dot layer, the second color quantum dot layer and the third color quantum dot layer away from the substrate.

[0253] For example, the second and third functional layers can be formed by direct vapor deposition.

[0254] For example, in one example, the second functional layer is a hole transport layer and the third functional layer is a hole injection layer. The materials of the second and third functional layers can be found in the relevant descriptions above, and will not be repeated here.

[0255] For example, a first electrode can be formed on the substrate before forming the pixel defining layer on the substrate, and the first electrode can be formed on the entire surface.

[0256] For example, the material of the first electrode includes a transparent conductive metal oxide or a conductive polymer. The conductive metal oxide may include indium tin oxide (ITO), indium zinc oxide (IZO), indium gallium oxide (IGO), zinc gallium oxide (GZO), zinc oxide (ZnO), indium oxide (In2O3), zinc aluminum oxide (AZO), and carbon nanotubes, etc.

[0257] For example, after forming the second and third functional layers, a second electrode can be formed on the side of the third functional layer away from the substrate. The material of the second electrode includes a conductive metal or a conductive metal oxide. For example, the material of the second electrode includes magnesium, aluminum, lithium monometal, or magnesium-aluminum alloy (MgAl), lithium-aluminum alloy (LiAl), etc.

[0258] For example, the first electrode is the anode and the second electrode is the cathode.

[0259] For example, in another example, the first electrode may be formed in the first sub-pixel region, the second sub-pixel region, and the third sub-pixel region respectively, and the second electrode may be formed over the entire surface.

[0260] For example, the structures of the first and second electrodes can be found in the relevant descriptions above, and will not be repeated here.

[0261] For example, Figure 12 This is a schematic diagram illustrating the fabrication process of an electroluminescent device according to at least one embodiment of the present disclosure, as shown below. Figure 12As shown, a first electrode 208 is formed on a substrate 201, and a pixel defining layer 202 is formed on the first electrode 208. The pixel defining layer 202 includes a plurality of openings to form a first sub-pixel region 2022a, a second sub-pixel region 2022b, and a third sub-pixel region 2022c spaced apart from each other. A first functional layer 209 and a first color quantum dot material 203' are formed in the first sub-pixel region 2022a, the second sub-pixel region 2022b, and the third sub-pixel region 2022c. A first mask 2031 is used to block the second sub-pixel region 2022b and the third sub-pixel region 2022c so that light can irradiate them. Exposure is performed on the first sub-pixel region 2022a to allow the first color quantum dot material 203' in the first sub-pixel region 2022a to undergo a cross-linking reaction, thus completing the exposure process of the first color quantum dot material 203' in the first sub-pixel region 2022a. The first color quantum dot material 203' that has not undergone a cross-linking reaction is then cleaned to remove the first color quantum dot material 203' located in the second sub-pixel region 2022b and the third sub-pixel region 2022c, thus forming the first color quantum dot layer 203. This process is repeated in the first sub-pixel region 2022a, the second sub-pixel region 2022b, and the third sub-pixel region 2022c. A first auxiliary layer 205 is applied to the side of the pixel defining layer 202 away from the substrate 201, i.e., the first auxiliary layer 205 is formed as a single layer; the second color quantum dot material 204' is spin-coated in the first sub-pixel region 2022a, the second sub-pixel region 2022b, and the third sub-pixel region 2022c, and the process of patterning the second color quantum dot material 204' includes: using a second mask 2032 to block the first sub-pixel region 2022a and the third sub-pixel region 2022c so that light shines on the second sub-pixel region 2022b, so that the second color quantum dots in the second sub-pixel region 2022b... The material 204' undergoes a cross-linking reaction, thus completing the exposure process of the second color quantum dot material 204'. The second color quantum dot material 204' that has not undergone a cross-linking reaction is cleaned to remove the second color quantum dot material 204' located in the first sub-pixel region 2022a and the third sub-pixel region 2022c, thus forming the second color quantum dot layer 204. A second auxiliary layer 207 is applied to the first sub-pixel region 2022a, the second sub-pixel region 2022b, and the third sub-pixel region 2022c, as well as on the side of the pixel defining layer 202 away from the substrate 201. That is, the second auxiliary layer 207 is formed as a whole layer.The process of spin-coating a third-color quantum dot material 206' into the first sub-pixel region 2022a, the second sub-pixel region 2022b, and the third sub-pixel region 2022c, and patterning the third-color quantum dot material 206', includes: using a third mask 2033 to block the first sub-pixel region 2022a and the second sub-pixel region 2022b, so that light can shine onto the third sub-pixel region 2022c, causing the third-color quantum dot material in the third sub-pixel region 2022c to undergo a cross-linking reaction, thus completing the exposure process of the third-color quantum dot material 206'; and cleaning the third-color quantum dot material 206' that has not undergone the cross-linking reaction to remove the third-color quantum dot material 206' located in the first sub-pixel region 2022a and the second sub-pixel region 2022b, thus forming the third-color quantum dot layer 206.

[0262] It should be noted that, although Figure 12 Although not shown in the image, the first color quantum dot material 203', the second color quantum dot material 204', and the third color quantum dot material 206' are also formed on the pixel defining layer 202.

[0263] For example, in one embodiment, the first color quantum dot layer 203, the second color quantum dot layer 204, and the third color quantum dot layer 206 can be a red quantum dot layer, a green quantum dot layer, and a blue quantum dot layer, respectively, and the embodiments disclosed herein are not limited thereto. The first auxiliary layer 205 can prevent the second color quantum dot material formed later from remaining on the first color quantum dot layer, and the second auxiliary layer 207 can prevent the third color quantum dot material formed later from remaining on the second color quantum dot layer and the first color quantum dot layer, thereby avoiding the problem of color mixing and improving the color gamut of the quantum dot electroluminescent device.

[0264] For example, Figure 13 The graphs show the emission peaks of blank glass, blank glass with quantum dots (without MPA ligands), blank glass with zinc oxide and quantum dots (without MPA ligands), and blank glass with zinc oxide and quantum dots (with MPA ligands) under 400 nm excitation light. Figure 13 As shown, under 400 nm excitation light, the blank glass exhibits no emission peak; under 400 nm excitation light, the blank glass with quantum dots (without MPA ligand) exhibits an emission peak; under 400 nm excitation light, the blank glass with zinc oxide and quantum dots (MPA ligand) exhibits no emission peak. This indicates that when the quantum dots have MPA ligands on their surface and contain zinc oxide, the subsequently formed quantum dot material leaves virtually no residue on the online-formed quantum dot layer. It should be noted that the MPA ligand is mercaptopropionic acid.

[0265] For example, Figure 14 This diagram illustrates the emission peak of red quantum dots (without MPA ligands) under 400 nm excitation light after ZnO sputtering and development. When red quantum dots (without MPA ligands) are deposited via ZnO sputtering, developed (washing away the red quantum dots), and then green quantum dots are deposited before device fabrication, a red emission peak is detected after device emission, indicating residual red quantum dots and incomplete development. In contrast, when red quantum dots (containing MPA ligands) are deposited via ZnO sputtering, developed (washing away the red quantum dots), and then green quantum dots are deposited before device fabrication, no red emission peak is detected after device emission, indicating no residual red quantum dots and complete development.

[0266] For example, Figure 15 This diagram illustrates the emission peak formed by red quantum dots (containing MPA ligands) under 400nm excitation light after sputtering ZnO, development (washing away the red quantum dots), and subsequent deposition of green quantum dots. Figure 15 As can be seen, no red emission peak was detected after the device emitted light, indicating that there was no residue of red quantum dots and the development was complete.

[0267] For example, Figure 16 This is a schematic diagram showing the emission peaks formed by green quantum dots (containing MPA ligands) under 400nm excitation light after sputtering ZnO and development. Figure 16 As can be seen, after the green quantum dots were deposited by sputtering ZnO, the device was fabricated, and no red signal was detected after the device emitted light.

[0268] For example, Figure 17 This is a schematic diagram illustrating the emission of light after green quantum dots are deposited by sputtering ZnO, followed by exposure cross-linking, deposition of red quantum dots (without MPA ligands), and development (washing away the red quantum dots). Figure 17 As shown, a red signal can be detected, proving that there are residual red quantum dots on the cross-linked green quantum dots.

[0269] The display substrate, electroluminescent device, and fabrication method thereof provided in at least one embodiment of this disclosure have at least one of the following beneficial technical effects:

[0270] (1) In the display substrate provided in at least one embodiment of the present disclosure, the first auxiliary layer can prevent the second color quantum dot material formed later from remaining on the first color quantum dot layer, thereby avoiding the problem of color mixing and improving the color gamut of the electroluminescent device including the display substrate.

[0271] (2) In the display substrate provided in at least one embodiment of the present disclosure, the second auxiliary layer can prevent the third color quantum dot material formed later from remaining on the second color quantum dot layer and the first color quantum dot layer, thereby avoiding the problem of color mixing and improving the color gamut of the electroluminescent device including the display substrate.

[0272] The following points need to be explained:

[0273] (1) The accompanying drawings of the embodiments of this disclosure only involve the structures involved in the embodiments of this disclosure. Other structures can be referred to the general design.

[0274] (2) For clarity, the thickness of layers or regions in the drawings used to describe embodiments of the present disclosure is enlarged or reduced, i.e., these drawings are not drawn to actual scale.

[0275] (3) Where there is no conflict, the embodiments of this disclosure and the features in the embodiments can be combined with each other to obtain new embodiments.

[0276] The above description is merely a specific embodiment of this disclosure, but the scope of protection of this disclosure is not limited thereto. The scope of protection of this disclosure should be determined by the scope of protection of the claims.

Claims

1. A display substrate, comprising: Substrate; A pixel defining layer is disposed on the substrate, wherein the pixel defining layer includes a plurality of openings, the plurality of openings corresponding to a plurality of sub-pixel regions, and the plurality of sub-pixel regions include at least a first sub-pixel region and a second sub-pixel region; A first color quantum dot layer is disposed in the first sub-pixel region; A second color quantum dot layer is set in the second sub-pixel region; The first auxiliary layer includes at least a first portion and a second portion spaced apart from each other. The first portion is disposed on the side of the first color quantum dot layer away from the substrate. The second portion is disposed on the side of the second color quantum dot layer close to the substrate.

2. The display substrate according to claim 1, wherein, The first part and the second part have the same thickness and are made of the same material.

3. The display substrate according to claim 2, wherein, The materials of the first part and the second part are metal oxides.

4. The display substrate according to claim 3, wherein, The surface roughness of the metal oxide is less than 3 nm.

5. The display substrate according to any one of claims 1 to 4, wherein, The first auxiliary layer further includes a third portion, which is disposed on the side of the pixel defining layer away from the substrate, and the first portion, the second portion and the third portion are not connected to each other.

6. The display substrate according to claim 5 further includes a second auxiliary layer and a third color quantum dot layer disposed in the third sub-pixel region, wherein, The second auxiliary layer is disposed at least on the side of the second color quantum dot layer away from the substrate.

7. The display substrate according to claim 6, wherein, The first auxiliary layer and the second auxiliary layer are made of different materials.

8. The display substrate according to claim 7, wherein, The first auxiliary layer is made of an electron transport oxide, the second auxiliary layer is made of a hole transport oxide, and at least a portion of the first auxiliary layer is in contact with the first color quantum dot layer, and at least a portion of the second auxiliary layer is in contact with the third color quantum dot layer.

9. The display substrate according to claim 8, wherein, The first color quantum dot layer is a blue quantum dot layer, the second color quantum dot layer is one of a red quantum dot layer and a green quantum dot layer, and the third color quantum dot layer is the other of the green quantum dot layer and the red quantum dot layer.

10. The display substrate according to any one of claims 6 to 9, wherein, The first color quantum dot layer includes first color quantum dots, the second color quantum dot layer includes second color quantum dots, and the third color quantum dot layer includes third color quantum dots. Each of these includes a quantum dot body and a ligand connected to the quantum dot body. The ligands all have an ABC structure, where A is a coordinating group connected to the quantum dot body; B is a photosensitive group reactant after light irradiation; and C is -COOH.

11. The display substrate according to any one of claims 6 to 9, wherein, The first color quantum dot layer includes first color quantum dots, the second color quantum dot layer includes second color quantum dots, and the third color quantum dot layer includes third color quantum dots. Each of these includes a quantum dot body and a ligand connected to the quantum dot body. The structure of each ligand is a mixture of AB-type ligands and AC-type ligands, where A is a coordinating group connected to the quantum dot body; B is a reactant of the photosensitive group after light irradiation; and C is -COOH.

12. The display substrate according to any one of claims 6 to 9, wherein, The second auxiliary layer includes at least a fourth portion, a fifth portion, and a sixth portion spaced apart from each other. The fourth portion is disposed on the side of the first portion away from the substrate and is at least partially in contact with the first portion. The fifth portion is disposed on the side of the second color quantum dot layer away from the substrate. The sixth portion is disposed on the side of the third color quantum dot layer close to the substrate.

13. The display substrate according to claim 12, wherein, The second auxiliary layer further includes a seventh portion that is spaced apart from the fourth portion, the fifth portion and the sixth portion. The seventh portion is disposed on the side of the third portion away from the substrate and is at least partially in contact with the third portion.

14. The display substrate according to claim 13, wherein, The first auxiliary layer further includes an eighth portion that is spaced apart from the first portion, the second portion and the third portion, and the eighth portion is disposed on the side of the sixth portion near the substrate.

15. The display substrate according to any one of claims 6 to 9, wherein, The materials of both the first auxiliary layer and the second auxiliary layer include at least one of electron transport oxide and hole transport oxide.

16. The display substrate according to claim 15, wherein, The materials of both the first auxiliary layer and the second auxiliary layer include at least one of zinc oxide, tin oxide, gallium nitride, aluminum nitride, molybdenum oxide, nickel oxide, zirconium oxide, vanadium oxide, zinc oxide doped with magnesium, tin, gallium, indium, zirconium, hafnium, yttrium, lithium or aluminum, and tin oxide doped with magnesium, tin, gallium, indium, zirconium, hafnium, yttrium, lithium or aluminum.

17. The display substrate according to any one of claims 6 to 9, wherein, The first auxiliary layer includes a stacked first layer structure and a second layer structure, wherein the first layer structure is located on the side of the second layer structure closer to the substrate. The material of the first layer structure includes at least one of electron transport oxides and hole transport oxides; The general formula for the second layer structure includes: Where A is -(CH2)nCH3, n is less than or equal to 4; M is -(CH2)x, x is less than or equal to 6; P includes , and At least one of them.

18. The display substrate according to claim 17, wherein, The second auxiliary layer includes a stacked third layer structure and a fourth layer structure, wherein the third layer structure is located on the side of the fourth layer structure closest to the substrate. The material of the third layer structure includes at least one of electron transport oxides and hole transport oxides; The general formula for the fourth layer structure includes: Where A is -(CH2)nCH3, n is less than or equal to 4; M is -(CH2)x, x is less than or equal to 6; P includes , and At least one of them.

19. The display substrate according to claim 18, wherein, The materials of the first layer structure and the third layer structure include at least one of zinc oxide, tin oxide, gallium nitride, aluminum nitride, molybdenum oxide, nickel oxide, zirconium oxide, vanadium oxide, zinc oxide doped with magnesium, tin, gallium, indium, zirconium, hafnium, yttrium, lithium or aluminum, and tin oxide doped with magnesium, tin, gallium, indium, zirconium, hafnium, yttrium, lithium or aluminum.

20. An electroluminescent device, comprising a display substrate according to any one of claims 1 to 5, and a first electrode and a first functional layer stacked on the substrate, wherein, The first electrode is disposed on the side of the first functional layer near the substrate; the display substrate further includes a third color quantum dot layer disposed in the third sub-pixel region. The first functional layer and the first electrode are both stacked in the plurality of sub-pixel regions, and the stacked first functional layer and the first electrode are located between the first color quantum dot layer and the substrate, between the second color quantum dot layer and the substrate, and between the third color quantum dot layer and the substrate.

21. The electroluminescent device according to claim 20, wherein, The first auxiliary layer and the first functional layer are made of the same material, and in the direction perpendicular to the main surface of the substrate, the thickness of the first functional layer is 4 to 5 times the thickness of the first auxiliary layer.

22. The electroluminescent device according to claim 21, wherein, The thickness of the first color quantum dot layer is 4 to 5 times the thickness of the first auxiliary layer.

23. A method for fabricating an electroluminescent device, comprising: Provide substrates; A pixel defining layer is formed on the substrate. The pixel defining layer includes a plurality of openings to form a plurality of sub-pixel regions spaced apart from each other. The plurality of sub-pixel regions include at least a first sub-pixel region, a second sub-pixel region, and a third sub-pixel region. A first color quantum dot layer is formed in the first sub-pixel region; A second color quantum dot layer is formed in the second sub-pixel region. The method further includes: forming a first auxiliary layer after forming the first color quantum dot layer and before forming the second color quantum dot layer, wherein the first auxiliary layer includes at least a first portion and a second portion spaced apart from each other, the first portion being disposed on the side of the first color quantum dot layer away from the substrate; and the second portion being disposed on the side of the second color quantum dot layer close to the substrate.

24. The preparation method according to claim 23, wherein, Before forming the first color quantum dot layer, the method further includes: forming a first functional layer on the substrate, wherein the first functional layer and the first auxiliary layer are bonded to each other in the second sub-pixel region and the third sub-pixel region.

25. The preparation method according to claim 23 or 24, wherein, The material of the first auxiliary layer includes at least one of electron transport oxide and hole transport oxide, and the first auxiliary layer is formed by magnetron sputtering.

26. The preparation method according to claim 23 or 24, wherein, Forming the first auxiliary layer includes forming a stacked first layer structure and a second layer structure, wherein the first layer structure is on the side of the second layer structure closer to the substrate, and forming the first layer structure includes applying at least one of an electron transport oxide and a hole transport oxide onto the substrate by magnetron sputtering. Forming the second layer structure includes immersing the substrate having the first layer structure in a solution of a silane coupling agent, the solution of which includes a first group containing a perfluorinated terminus.

27. The preparation method according to claim 24, wherein, A second auxiliary layer is formed at least on the side of the second color quantum dot layer away from the substrate. A third color quantum dot layer is formed on the side of the second auxiliary layer away from the substrate and in the third sub-pixel region; The first auxiliary layer and the second auxiliary layer are made of different materials.

28. The preparation method according to claim 27, wherein, The material of the second auxiliary layer includes at least one of electron transport oxide and hole transport oxide, and the second auxiliary layer is formed by magnetron sputtering.

29. The preparation method according to claim 27, wherein, Forming the second auxiliary layer includes forming a stacked third layer structure and a fourth layer structure, wherein the third layer structure is on the side of the fourth layer structure close to the substrate, and forming the third layer structure includes applying at least one of an electron transport oxide and a hole transport oxide onto the substrate by magnetron sputtering. Forming the fourth layer structure includes immersing a substrate having the third layer structure in a solution of a silane coupling agent, the solution of which includes a third group containing a perfluorinated terminus.

30. The preparation method according to claim 27, wherein, Forming the first color quantum dot layer includes: depositing a first color quantum dot material on the first functional layer, and cross-linking and developing the first color quantum dot material in the first sub-pixel region to form the first color quantum dot layer; Forming the second color quantum dot layer includes: depositing a second color quantum dot material on the first functional layer, and cross-linking and developing the second color quantum dot material in the second sub-pixel region to form the second color quantum dot layer; Forming the third color quantum dot layer includes: depositing a third color quantum dot material on the first functional layer, cross-linking the third color quantum dot material within the third sub-pixel region, and developing the material to form the third color quantum dot layer.

31. The preparation method according to any one of claims 28 to 30, wherein, The first auxiliary layer is made of an electron transport oxide, the second auxiliary layer is made of a hole transport oxide, and at least a portion of the first auxiliary layer is in contact with the first color quantum dot layer, and at least a portion of the second auxiliary layer is in contact with the third color quantum dot layer.

32. The preparation method according to claim 27, wherein, After forming the first color quantum dot layer, the second color quantum dot layer, and the third color quantum dot layer, a second functional layer and a third functional layer are sequentially formed on the side of the first color quantum dot layer, the second color quantum dot layer, and the third color quantum dot layer away from the substrate.

33. The preparation method according to claim 32 further comprises: A first electrode is formed on the substrate prior to the formation of the first functional layer, wherein the material of the first electrode includes a transparent conductive metal oxide or a conductive polymer; A second electrode is formed on the side of the third functional layer away from the substrate, and the material of the second electrode includes a conductive metal or a conductive metal oxide.

34. The preparation method according to any one of claims 27 to 30, wherein, The first auxiliary layer and the second auxiliary layer are sequentially formed on the surface of the pixel defining layer away from the substrate.

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