Display substrate and display device

Abstract

The present application provides a display substrate and a display device. The display substrate includes a substrate, a cathode layer and an anode layer located on the substrate, a quantum dot light-emitting layer, an electron transport layer, and an expansion layer. The quantum dot light-emitting layer is located between the cathode layer and the anode layer. The electron transport layer is located between the cathode layer and the quantum dot light-emitting layer. The expansion layer is located between at least a part of the electron transport layer and the quantum dot light-emitting layer; the expansion layer is configured to expand when the display substrate is operating, and the expansion coefficient of the expansion layer is greater than the expansion coefficient of the electron transport layer. The display device includes the display substrate.

Description

Technical Field

[0001] The present application relates to the field of display technology, and in particular to a display substrate and a display device. Background Art

[0002] QLED (Quantum Dot Light Emitting Diode) has the characteristics of high color purity, high contrast and adjustable luminous color, and has broad application prospects in display panels and other fields.

[0003] Currently, QLED display devices have the problem of unbalanced electron and hole injection, which affects the service life of QLED display devices. Summary of the invention

[0004] The present application provides a display substrate and a display device.

[0005] A first aspect of an embodiment of the present application provides a display substrate. The display substrate comprises:

[0006] substrate;

[0007] a cathode layer and an anode layer located on the substrate;

[0008] A quantum dot light-emitting layer, located between the cathode layer and the anode layer;

[0009] An electron transport layer, located between the cathode layer and the quantum dot light-emitting layer;

[0010] The expansion layer is located between at least a portion of the electron transport layer and the quantum dot light-emitting layer; the expansion layer is configured to expand when the display substrate is working, and the expansion coefficient of the expansion layer is greater than the expansion coefficient of the electron transport layer.

[0011] In one embodiment, the material of the expansion layer includes at least one of a thermal expansion material and an electrical expansion material.

[0012] In one embodiment, the thermal expansion material includes at least one of a semiconductor material, a polymer material, and a thermal isomerization material; and the electrical expansion material includes at least one of an electroactive polymer material and a piezoelectric material.

[0013] In one embodiment, the electron transport layer includes a first electron transport film layer and a second electron transport film layer located on a side of the first electron transport film layer away from the substrate, and the expansion layer is located between the first electron transport film layer and the second electron transport film layer.

[0014] In one embodiment, the expansion layer is provided with a plurality of hollow portions, or the expansion layer includes a plurality of expansion structures arranged at intervals; in the horizontal direction, the expansion coefficient of the expansion layer is greater than that of the electron transport layer, and / or in the film layer stacking direction of the display substrate, the expansion coefficient of the expansion layer is greater than that of the electron transport layer.

[0015] In one embodiment, the orthographic projection of the expansion layer on the substrate coincides with the orthographic projection of the first electron transport film layer on the substrate, and the thickness range of the expansion layer is 5 nm to 10 nm; in the film layer stacking direction of the display substrate, the expansion coefficient of the expansion layer is greater than that of the electron transport layer in the film layer stacking direction.

[0016] In one embodiment, the expansion layer is located between the electron transport layer and the quantum dot light-emitting layer, and the expansion layer is in contact with the quantum dot light-emitting layer.

[0017] In one embodiment, the expansion layer is provided with a hollow portion, and part of the electron transport layer is filled in the hollow portion; or the expansion layer includes a plurality of expansion structures arranged at intervals, and part of the electron transport layer is filled between adjacent expansion structures; in the horizontal direction, the expansion coefficient of the expansion layer is greater than that of the electron transport layer, and / or in the film layer stacking direction of the display substrate, the expansion coefficient of the expansion layer is greater than that of the electron transport layer.

[0018] In one embodiment, the expansion layer is provided with a hollow portion, and part of the quantum dot light-emitting layer is filled in the hollow portion; or the expansion layer includes a plurality of expansion structures arranged at intervals, and part of the quantum dot light-emitting layer is filled between adjacent expansion structures; in the film layer stacking direction of the display substrate, the expansion coefficient of the expansion layer is greater than that of the electron transport layer.

[0019] In one embodiment, the orthographic projection of the expansion layer on the substrate coincides with the orthographic projection of the electron transport layer on the substrate, and the thickness range of the expansion layer is 5 nm to 10 nm; in the film layer stacking direction of the display substrate, the expansion coefficient of the expansion layer is greater than that of the electron transport layer.

[0020] In a second aspect of the embodiments of the present application, a display device is provided, and the display device includes the above-mentioned display substrate.

[0021] The display substrate and the display device provided by the embodiments of the present application are provided with an expansion layer located between at least a part of the electron transport layer and the quantum dot light-emitting layer. When the display substrate is working, the expansion layer expands, which can compress the electron transport channels in the electron transport layer and / or increase the transport distance of electrons from the cathode layer to the quantum dot light-emitting layer, thereby reducing the transport efficiency of electrons to the quantum dot light-emitting layer, improving the problem of imbalance in electron and hole injection caused by excessive electron injection in the quantum dot light-emitting layer, and extending the service life of the display substrate; moreover, the reduction in the transport efficiency of electrons to the quantum dot light-emitting layer can also reduce the current of the display substrate, which is beneficial to reducing the heat generated during the operation of the display substrate and helps to extend the service life of the quantum dot light-emitting layer.

[0022] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings herein are incorporated into the specification and form a part of the specification, showing embodiments consistent with the present application, and are used together with the specification to explain the principles of the present application.

[0024] Figure 1 It is a cross-sectional view of a display substrate provided by an exemplary embodiment of the present application;

[0025] Figure 2 It is a cross-sectional view of a display substrate provided by another exemplary embodiment of the present application;

[0026] Figure 3 It is a cross-sectional view of a display substrate provided by still another exemplary embodiment of the present application;

[0027] Figure 4 It is a cross-sectional view of a display substrate provided by yet another exemplary embodiment of the present application;

[0028] Figure 5 It is a cross-sectional view of a display substrate provided by yet another exemplary embodiment of the present application;

[0029] Figure 6 It is a partial structural cross-sectional view of the expansion layer of the display substrate provided by an exemplary embodiment of the present application before and after expansion;

[0030] Figure 7 It is a partial structural cross-sectional view of the display substrate provided by an exemplary embodiment of the present application cut along the horizontal direction;

[0031] Figure 8 It is a scanning electron microscope image of a polymer material film layer provided by an exemplary embodiment of the present application;

[0032] Figure 9aSEM image of the expansion layer provided by an exemplary embodiment of the present application;

[0033] Figure 9b SEM image of the expansion layer provided by another exemplary embodiment of the present application;

[0034] Figure 9c SEM image of the expansion layer provided by yet another exemplary embodiment of the present application;

[0035] Figure 9d SEM image of the expansion layer provided by still another exemplary embodiment of the present application;

[0036] Figure 10 SEM image of the second electron transport film layer provided by an exemplary embodiment of the present application. Detailed implementation manners

[0037] Here, the exemplary embodiments will be described in detail, and the examples are shown in the drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementation manners described in the following exemplary embodiments do not represent all the implementation manners consistent with the present application. On the contrary, they are only examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0038] The terms used in the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. The singular forms "a", "the" and "said" used in the present application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0039] It should be understood that the "first", "second" and similar terms used in the specification and claims of the present application do not represent any order, quantity or importance, but are only used to distinguish different components. Similarly, the similar terms such as "one" or "a" do not represent a quantity limitation, but indicate that there is at least one. Unless otherwise specified, the similar terms such as "front part", "rear part", "lower part" and / or "upper part" are only for convenience of description and are not limited to a position or a spatial orientation. The terms "include" or "comprise" and similar terms mean that the elements or objects appearing before "include" or "comprise" cover the elements or objects listed after "include" or "comprise" and their equivalents, and do not exclude other elements or objects.

[0040] The embodiments of the present application provide a display substrate and a display device. The display substrate and the display device according to the embodiments of the present application will be described in detail below with reference to the drawings. Without conflict, the features in the following embodiments and implementation manners can be mutually supplemented or combined.

[0041] An embodiment of the present application provides a display substrate. As Figures 1 to 5 shown, the display substrate includes a substrate 10, a cathode layer 20 and an anode layer 80 located on the substrate 10, a quantum dot light-emitting layer 50 located between the cathode layer 20 and the anode layer 80, an electron transport layer 30 located between the cathode layer 20 and the quantum dot light-emitting layer 50, and a swelling layer 40 located between at least a part of the electron transport layer 30 and the quantum dot light-emitting layer 50. The swelling layer 40 is configured to swell when the display substrate is working, and the coefficient of thermal expansion of the swelling layer 40 is greater than that of the electron transport layer 30.

[0042] For the display substrate provided by the embodiment of the present application, by providing the swelling layer 40 located between at least a part of the electron transport layer 30 and the quantum dot light-emitting layer 50, when the display substrate is working, the swelling layer 40 swells, which can compress the electron transport channels in the electron transport layer 30, and / or increase the transport distance of electrons from the cathode layer 20 to the quantum dot light-emitting layer 50, thereby reducing the transport efficiency of electrons to the quantum dot light-emitting layer 50, improving the problem of imbalance in electron and hole injection caused by excessive electron injection in the quantum dot light-emitting layer 50, and enhancing the service life of the display substrate; and the reduction of the transport efficiency of electrons to the quantum dot light-emitting layer 50 can also reduce the current of the display substrate, which is beneficial to reducing the heat generated during the operation of the display substrate and helps to improve the service life of the quantum dot light-emitting layer 50.

[0043] In one embodiment, the swelling layer 40 being located between at least a part of the electron transport layer 30 and the quantum dot light-emitting layer 50 means that the swelling layer 40 is located between a part of the thickness of the electron transport layer 30 and the quantum dot light-emitting layer 50, and another part of the thickness of the electron transport layer 30 can be located between the swelling layer 40 and the quantum dot light-emitting layer 50; or it can also mean that the swelling layer 40 is located between the entire thickness of the electron transport layer 30 and the quantum dot light-emitting layer 50.

[0044] In one embodiment, the substrate 10 can be a flexible substrate or a rigid substrate. The material of the flexible substrate can include one or more of polyimide, polyethylene terephthalate, and polycarbonate. The material of the rigid substrate can be glass.

[0045] In one embodiment, the display substrate includes a plurality of sub-pixels, and the plurality of sub-pixels of the display substrate include sub-pixels of at least three different light-emitting colors. For example, the display substrate can include sub-pixels of three different light-emitting colors: red sub-pixels, green sub-pixels, and blue sub-pixels; the quantum dot light-emitting layer includes a red quantum dot light-emitting layer, a green quantum dot light-emitting layer, and a blue quantum dot light-emitting layer.

[0046] In one embodiment, as Figures 1 to 5As shown, the display substrate is an inverted structure, the cathode layer 20 is located on the side of the quantum dot light-emitting layer 50 facing the substrate 10 , and the anode layer 80 is located on the side of the quantum dot light-emitting layer 50 facing away from the substrate 10 .

[0047] In another embodiment, the display substrate is a positive structure, the cathode layer is located on a side of the quantum dot light-emitting layer away from the substrate, and the anode layer is located on a side of the quantum dot light-emitting layer facing the substrate.

[0048] In one embodiment, the display substrate further includes a pixel driving circuit layer. When the display substrate is an inverted structure, the pixel driving circuit layer is located between the substrate 10 and the cathode layer 20; when the display substrate is an upright structure, the pixel driving circuit layer is located between the substrate and the anode layer. The pixel driving circuit layer includes a plurality of pixel circuits, the display substrate includes a plurality of sub-pixels, the pixel circuits may correspond to the sub-pixels one by one, and each pixel circuit drives the corresponding sub-pixel. The pixel circuit includes a thin film transistor and a capacitor.

[0049] In one embodiment, the cathode layer 20 may be a transparent cathode layer, which means that the cathode layer 20 has a high transmittance to light, for example, the transmittance to light is greater than 70%; the material of the transparent cathode layer may include one or more of indium tin oxide, fluorine-doped tin oxide, and conductive polymers. In other embodiments, the cathode layer 20 may be an opaque cathode layer, which means that the cathode layer has a low transmittance to light, for example, the transmittance to light is less than 30%, and the material of the opaque cathode layer may include one or more of metal materials such as aluminum and silver.

[0050] In one embodiment, the material of the anode layer 80 may include one or more metal materials such as aluminum and silver, or the material of the anode layer 80 may also include a transparent conductive material such as indium zinc oxide. When the material of the anode layer 80 is a transparent conductive material such as indium zinc oxide, the anode layer 80 may be formed by magnetron sputtering.

[0051] In one embodiment, the thickness of the anode layer 80 may be in the range of 10 nm to 100 nm. The thickness of the anode layer 80 may be, for example, 10 nm, 20 nm, 40 nm, 60 nm, 80 nm, 100 nm, etc.

[0052] In one embodiment, the material of the electron transport layer 30 may be zinc oxide, or the material of the electron transport layer 30 is zinc oxide doped with components such as magnesium, aluminum, zirconium, and yttrium. The electron transport layer 30 may be formed by sputtering. When the quantum dot light-emitting layer 50 is prepared by a solution method, if the material of the electron transport layer includes an organic material, the solution used to prepare the quantum dot light-emitting layer will dissolve the organic material in the electron transport layer 30, forming defects on the surface of the electron transport layer. The electron transport layer 30 formed by the sputtering process does not contain organic components, which can prevent the formation of defects on the surface of the electron transport layer 30 during the subsequent preparation of the quantum dot light-emitting layer 50.

[0053] In one embodiment, the thickness range of the electron transport layer 30 may be 50 nm to 300 nm. For example, the thickness of the electron transport layer 30 may be 50 nm, 100 nm, 150 nm, 200 nm, 250 nm, or 300 nm.

[0054] In one embodiment, the thicknesses of the portions of the electron transport layer 30 corresponding to different light-emitting color sub-pixels may be different. If the thicknesses of the portions of the electron transport layer 30 corresponding to different color sub-pixels are different, the electron transport efficiencies of the portions of the electron transport layer 30 corresponding to different color sub-pixels are different, which is more conducive to achieving the transport balance of holes and electrons corresponding to the quantum dot light-emitting layer and different color sub-pixels, and improving the device performance of the display substrate.

[0055] In one embodiment, as Figures 1 to 5 shown, the display substrate further includes a hole transport layer 60 and a hole injection layer 70 located between the anode layer 80 and the quantum dot light-emitting layer 50, and the hole injection layer 70 is located on the side of the hole transport layer 60 away from the quantum dot light-emitting layer 50.

[0056] In one embodiment, the material of the expansion layer 40 includes at least one of a thermal expansion material and an electro-expansion material. When the display substrate is working, the temperature of the display substrate rises. When the material of the expansion layer 40 includes a thermal expansion material, the expansion layer 40 expands when heated. When the display substrate is working, there is a voltage difference between the cathode layer 20 and the anode layer 80, and an electric field is formed between the cathode layer 20 and the anode layer 80. When the material of the expansion layer 40 includes an electro-expansion material, the electro-expansion material expands under the action of an electric field or voltage. In some embodiments, the material of the expansion layer 40 may be all thermal expansion materials, or the material of the expansion layer 40 may be all electro-expansion materials, or the material of the expansion layer 40 includes a thermal expansion material and an electro-expansion material.

[0057] In one embodiment, the thermal expansion material includes at least one of a semiconductor material, a polymer material, and a thermally isomerizable material. The thermally isomerizable material refers to a material whose structure changes from cis to trans when heated, and the molecular volume of the trans structure of the thermally isomerizable material is larger than that of the cis structure. When the material of the expansion layer 40 is a semiconductor material, the material of the expansion layer 40 may include one or more of alumina, aluminum nitride, gallium nitride, gallium arsenide, etc. When the material of the expansion layer 40 is a polymer material, the material of the expansion layer 40 may be a material such as polystyrene. When the material of the expansion layer 40 is a thermally isomerizable material, the material of the expansion layer 40 may include one or more of a boron difluoride coordinated azo compound, α-linolenic acid, etc.

[0058] In one embodiment, the electro-expansion material includes at least one of an electroactive polymer material and a piezoelectric material. When the material of the expansion layer 40 is an electroactive polymer material, the material of the expansion layer 40 may be an ionic electroactive polymer material or a dielectric elastomer. The ionic electroactive polymer material is, for example, a carbon nanotube / polymer nanocomposite, polyacetylene, a copolymer or homopolymer of an aromatic monocyclic, aromatic polycyclic, and heterocyclic ring, polyether, polyester, polyimide, etc. The dielectric elastomer is, for example, a material such as polyacrylate, silicone rubber, polydimethylsiloxane. When the material of the expansion layer 40 is a piezoelectric material, the material of the expansion layer 40 may include one or more of polyvinylidene fluoride-based materials (such as vinylidene fluoride-trifluoroethylene copolymer), barium titanate, lead zirconate titanate, etc. In one embodiment, the thermally isomerizable material is an azobenzene-based material. When azobenzene is heated, its structural formula changes from cis to trans, and the chemical reaction that occurs is shown by the following reaction formula:

[0059]

[0060] In one embodiment, the thermally isomerizable material is a fluorine-substituted azobenzene-based material, and the compounds with a trans structure obtained after the thermally isomerizable material undergoes a reaction can be shown as the following Compounds A1 - A13 (Compounds A1 - A13 are all in trans structure):

[0061]

[0062] In Compounds A1 - A13, the R1 group and the R2 group can be an alkyl chain or a silane coupling group.

[0063] In one embodiment, the thermally isomerizable material is a boron difluoride coordinated azo compound, and when it is heated, its structural formula changes from cis to trans, and the chemical reaction that occurs is shown by the following reaction formula:

[0064]

[0065] In the above reaction formula, the R3 group can be an alkyl chain or a silane coupling group.

[0066] The material of the electron transport layer 30 in the present application can be zinc oxide. When the material of the expansion layer 40 is a thermal expansion material, the thermal expansion material can be, for example, one or more of materials such as aluminum oxide, aluminum nitride, gallium arsenide, gallium nitride, polystyrene and other polymer materials. Table 1 shows the thermal expansion coefficients of zinc oxide and the above-mentioned thermal expansion materials. As can be seen from Table 1, when the material of the expansion layer 40 is a polymer material such as aluminum oxide, aluminum nitride, gallium arsenide, gallium nitride, polystyrene, etc., in the horizontal direction and in the film layer stacking direction, the expansion coefficient of the expansion layer 40 is greater than the expansion coefficient of the electron transport layer 30. The setting of the expansion layer can effectively reduce the transmission efficiency of electrons and improve the device performance of the display substrate.

[0067] Table 1

[0068] Material Coefficient of thermal expansion in the horizontal direction Coefficient of thermal expansion in the film stacking direction Zinc oxide <![CDATA[2.9×10 -6 m / mK]]> <![CDATA[4.75×10 -6 m / mK]]> Aluminum oxide <![CDATA[7.5×10 -6 m / mK]]> <![CDATA[8.5×10 -6 m / mK]]> Aluminum nitride <![CDATA[4.15×10 -6 m / mK]]> <![CDATA[5.25×10 -6 m / mK]]> Gallium arsenide <![CDATA[5.75×10 -6 m / mK]]> <![CDATA[5.75×10 -6 m / mK]]> Gallium nitride <![CDATA[5.59×10 -6 m / mK]]> <![CDATA[5.59×10 -6 m / mK]]> Polystyrene <![CDATA[> 100×10 -6 m / mK]]> <![CDATA[> 100×10 -6 m / mK]]>

[0069] In one embodiment, Figure 1 and Figure 2 As shown, the electron transport layer 30 includes a first electron transport film layer 301 and a second electron transport film layer 302 located on the side of the first electron transport film layer 301 away from the substrate, and the expansion layer 40 is located between the first electron transport film layer 301 and the second electron transport film layer 302. The second electron transport film layer 302 covers the expansion layer 40 and is electrically connected to the first electron transport film layer 301.

[0070] In one embodiment, Figure 1 As shown, the expansion layer 40 is provided with a plurality of hollow portions, and the expansion layer is located between the first electron transport film layer 301 and the second electron transport film layer 302 , and part of the second electron transport film layer 302 is filled in the plurality of hollow portions and is in direct contact with the first electron transport film layer 301 .

[0071] Furthermore, the expansion coefficient of the expansion layer 40 in the horizontal direction is greater than that of the electron transport layer 30. The horizontal direction refers to the direction parallel to the extension direction of the substrate 10. With such a setting, when the display substrate is working, the expansion size of the expansion layer 40 in the horizontal direction is greater than that of the electron transport layer 30 in the horizontal direction. Generally, the expansion size of the electron transport layer 30 in the horizontal direction can be ignored. The thickness of the expansion layer 40 increases in the horizontal direction, and the part of the second electron transport film layer 302 located in the hollow part of the expansion layer 40 is extruded by the expansion layer 40, making the atomic arrangement of the part of the second electron transport film layer 302 located in the hollow part more compact, and the gap between adjacent atoms becomes narrower. During the process of electrons being transmitted to the quantum dot light-emitting layer 50, they are first transmitted from the first electron transport film layer 301 to the second electron transport film layer 302, and then from the second electron transport film layer 302 to the quantum dot light-emitting layer 50. Since the distance between adjacent atoms of the part of the second electron transport film layer 302 located in the hollow part becomes narrower, that is, the electron transmission channel becomes narrower, the electron transmission efficiency decreases.

[0072] Furthermore, the expansion coefficient of the expansion layer 40 in the direction of the film stack is greater than that of the electron transport layer 30. The direction of the film stack refers to the direction from the substrate 10 to the cathode layer 20. With such a setting, when the display substrate is working, the expansion layer 40 expands in the direction of the film stack, increasing the distance between the cathode layer 20 and the quantum dot light-emitting layer 50, that is, increasing the transmission distance of electrons in the direction of the film stack, and the electron transmission efficiency can be reduced.

[0073] In one embodiment, the expansion coefficient of the expansion layer 40 in the horizontal direction is greater than that of the electron transport layer 30, and the expansion coefficient of the expansion layer 40 in the direction of the film stack of the display substrate is greater than that of the electron transport layer 30. With such a setting, during the working process of the display substrate, the expansion layer 40 expands in both the horizontal direction and the direction of the film stack, which can not only narrow the electron transmission channel, but also increase the transmission distance of electrons from the cathode layer 20 to the quantum dot light-emitting layer in the direction of the film stack, effectively reducing the electron transmission efficiency and effectively improving the balance between electrons and holes injected into the quantum dot light-emitting layer.

[0074] In this embodiment, the thickness range of the expansion layer 40 can be 10 nm to 100 nm. If the thickness of the expansion layer 40 is too small, the deformation after expansion of the expansion layer 40 is not obvious, and it cannot effectively compress the electron transport channel or increase the electron transport distance. If the thickness of the expansion layer 40 is large, it will cause the thickness of the electron transport layer 30 to be large, which may reduce the electron transport efficiency too much and affect the light emission efficiency of the quantum dot light emitting layer 50. Setting the thickness of the expansion layer 40 within the above range can reduce the heat generated during the operation of the display substrate while not affecting the device performance of the display substrate. The thickness of the expansion layer 40 can be, for example, 10 nm, 30 nm, 60 nm, 90 nm, 100 nm, etc.

[0075] In one embodiment, the volume ratio range of the expansion layer 40 to the electron transport layer 30 can be 40% to 60%. If the volume ratio of the expansion layer 40 to the electron transport layer 30 is too small, it cannot effectively compress the electron transport channel or increase the electron transport distance. If the volume ratio of the expansion layer 40 to the electron transport layer 30 is too large, it may reduce the electron transport efficiency too much, resulting in too few electrons injected into the quantum dot light emitting layer 50, thereby affecting the light emission efficiency of the quantum dot light emitting layer. Setting the volume ratio of the expansion layer 40 to the electron transport layer 30 within the above range can reduce the heat generated during the operation of the display substrate while not affecting the device performance of the display substrate. The volume ratio of the expansion layer 40 to the electron transport layer 30 can be, for example, 40%, 45%, 50%, 55%, 60%.

[0076] In one embodiment, when the expansion layer 40 is provided with a plurality of hollow portions, the material of the expansion layer can be a semiconductor material. When forming the expansion layer 40, a semiconductor film layer covering the first electron transport film layer 301 can be first formed on the first electron transport film layer 301, and then the semiconductor film layer is etched to form a plurality of hollow portions, thereby obtaining the expansion layer 40. In other embodiments, the material of the expansion layer 40 can be other materials, such as polymer materials, thermally isomerizable materials, etc.

[0077] In one embodiment, as Figure 1 shown, the expansion layer 40 includes a plurality of expansion structures arranged at intervals. The expansion layer is located between the first electron transport film layer 301 and the second electron transport film layer 302, and part of the second electron transport film layer 302 is located between the expansion structures.

[0078] Furthermore, the expansion coefficient of the expansion layer 40 in the horizontal direction is greater than that of the electron transport layer 30. The horizontal direction refers to the direction parallel to the extension direction of the substrate. With such a setting, when the display substrate is working, the expansion size of the expansion layer 40 in the horizontal direction is greater than that of the electron transport layer 30 in the horizontal direction. Generally, the expansion of the electron transport layer 30 in the horizontal direction can be ignored. The thickness of the expansion layer 40 in the horizontal direction increases, and the second electron transport film layer 302 located between the expansion structures is squeezed by the expansion layer, making the atomic arrangement of the second electron transport film layer 302 between the expansion structures more compact, and the gap between adjacent atoms becomes narrower. When electrons are transmitted to the quantum dot light-emitting layer, they are first transmitted from the first electron transport film layer 301 to the second electron transport film layer 302, and then from the second electron transport film layer 302 to the quantum dot light-emitting layer 50. Since the distance between adjacent atoms of the part of the second electron transport film layer 302 located in the hollow part becomes narrower, that is, the electron transmission channel becomes narrower, the electron transmission efficiency decreases.

[0079] Furthermore, the expansion coefficient of the expansion layer 40 in the direction of film layer lamination is greater than that of the electron transport layer 30. The film layer lamination direction refers to the direction from the substrate 10 to the cathode layer 20. With such a setting, when the display substrate is working, the expansion layer 40 expands in the direction of film layer lamination, increasing the distance between the cathode layer 20 and the quantum dot light-emitting layer 50, that is, increasing the electron transmission distance in the direction of film layer lamination, and reducing the electron transmission efficiency.

[0080] In one embodiment, when the expansion coefficient of the expansion layer 40 in the horizontal direction is greater than that of the electron transport layer, and the expansion coefficient of the expansion layer 40 in the direction of film layer lamination of the display substrate is greater than that of the electron transport layer. With such a setting, during the working process of the display substrate, when the expansion coefficients in both the horizontal direction and the direction of film layer lamination are greater than those of the electron transport layer, after the expansion layer 40 expands in both the horizontal direction and the direction of film layer lamination, it can not only compress to narrow the electron transmission channel, but also increase the electron transmission distance from the expansion layer 40 to the quantum dot light-emitting layer in the direction of film layer lamination, making the effect of reducing the electron transmission efficiency more significant and effectively improving the balance between electrons and holes injected into the quantum dot light-emitting layer.

[0081] In one embodiment, the thickness range of the swelling layer 40 may be 10 nm to 100 nm. If the thickness of the swelling layer 40 is too small, the deformation after the swelling of the swelling layer 40 is not obvious, and it cannot effectively compress the electron transport channel or increase the electron transport distance. If the thickness of the swelling layer 40 is large, it will cause the thickness of the electron transport layer 30 to be large, which may reduce the electron transport efficiency too much and affect the light-emitting efficiency of the quantum dot light-emitting layer 50. Setting the thickness of the swelling layer 40 within the above range can reduce the electron transport efficiency and reduce the heat generated during the operation of the display substrate, while not affecting the normal device performance of the display substrate. The thickness of the swelling layer 40 may be, for example, 10 nm, 30 nm, 60 nm, 90 nm, 100 nm, etc.

[0082] In one embodiment, the volume ratio range of the swelling layer 40 to the electron transport layer 30 may be 40% to 60%. If the volume ratio of the swelling layer 40 to the electron transport layer 30 is too small, it cannot effectively compress the electron transport channel or increase the electron transport distance. If the volume ratio of the swelling layer 40 to the electron transport layer 30 is too large, it may reduce the electron transport efficiency too much, resulting in too few electrons injected into the quantum dot light-emitting layer, and thus affecting the light-emitting efficiency of the quantum dot light-emitting layer. Setting the volume ratio of the swelling layer 40 to the electron transport layer 30 within the above range can reduce the heat generated during the operation of the display substrate while not affecting the device performance of the display substrate. The volume ratio of the swelling layer 40 to the electron transport layer 30 may be, for example, 40%, 45%, 50%, 55%, 60%, etc.

[0083] In this embodiment, as Figure 6 and Figure 7 shown, the swelling structure 41 may be a spherical structure, and the material of the swelling structure may be a polymer material, such as polystyrene material. When preparing the swelling structure of the polymer material, a polymer material film layer may be first deposited on the first electron transport film layer. The polymer material film layer includes a plurality of closely arranged spherical structures, and then the polymer material film layer is etched to obtain a plurality of spaced-apart swelling structures. Figure 8It is a scanning electron microscope image of a polymer material film layer. The material of the polymer material film layer is polystyrene, and the size of the polystyrene spherical structure is about 240 nm. Figures 9(a) to 9(d) are scanning electron microscope images of the expanded structure obtained by etching the polymer material film layer using the oxygen plasma etching method. Among them, Figure 9(a) is the scanning electron microscope image of the expanded structure obtained when the etching duration of the polymer material film layer is 60 s, and the size of the expanded structure is about 110 nm; Figure 9(b) is the scanning electron microscope image of the expanded structure obtained when the etching duration of the polymer material film layer is 70 s, and the size of the expanded structure is about 100 nm; Figure 9(c) is the scanning electron microscope image of the expanded structure obtained when the etching duration of the polymer material film layer is 80 s, and the size of the expanded structure is about 70 nm; Figure 9(d) is the scanning electron microscope image of the expanded structure obtained when the etching duration of the polymer material film layer is 90 s, and the size of the expanded structure is about 50 nm. In other embodiments, the material of the expanded structure may also be other materials, such as semiconductor materials, thermally isomerizable materials, etc.

[0084] In one embodiment, when the expansion layer 40 includes a plurality of spaced-apart expansion structures, through holes are formed in the regions of the second electron transport film layer 302 corresponding to the expansion structures on the expansion layer 40, so that the second electron transport film layer 302 has a grid-like structure, as Figure 10 shown.

[0085] In one embodiment, as Figure 2 shown, the orthographic projection of the expansion layer 40 on the substrate coincides with the orthographic projection of the first electron transport film layer 301 on the substrate 10, and the thickness range of the expansion layer 40 is 5 nm to 10 nm; in the film layer stacking direction of the display substrate, the expansion coefficient of the expansion layer 40 is greater than the expansion coefficient of the electron transport layer 30.

[0086] In this embodiment, the swelling layer 40 entirely covers the first electron transport film layer 301, and the second electron transport film layer 302 is located on a side of the swelling layer 40 away from the substrate 10. According to the tunneling effect, when the thickness of the swelling layer 40 is small, electrons can tunnel through the swelling layer 40 and enter the second electron transport film layer 302. Since the coefficient of thermal expansion of the swelling layer 40 in the film stacking direction of the display substrate is greater than that of the electron transport layer 30, when the display substrate is operating, the swelling layer 40 expands in the film stacking direction of the display substrate, and the thickness of the swelling layer 40 increases. As a result, the distance from the cathode layer 20 to the quantum dot light-emitting layer 50 increases, the electron transport distance increases, the electron transport efficiency can be reduced, and it helps to balance the carriers injected into the quantum dot light-emitting layer 50. By setting the thickness range of the swelling layer 40 to be 5 nm to 10 nm, it is possible to avoid the thickness of the swelling layer 40 after expansion being too small to effectively increase the distance between the cathode layer 20 and the quantum dot light-emitting layer 50, and thus the electron transport efficiency cannot be effectively reduced. It is also possible to avoid the thickness of the swelling layer 40 being too large, resulting in electrons being unable to enter the second electron transport film layer 302 through the swelling layer 40.

[0087] In one embodiment, as Figures 3 to 5 shown, the swelling layer 40 is located between the electron transport layer 30 and the quantum dot light-emitting layer 50, and the swelling layer 40 is in contact with the quantum dot light-emitting layer 50. During the preparation of the electron transport layer 30, some defects will be formed on the surface of the electron transport layer 30 away from the substrate 10. When the display substrate is operating, the surface defects of the electron transport layer 30 will become electron traps, causing the quenching of excitons in the quantum dot light-emitting layer 50. The swelling layer 40 can cover at least part of the surface defects of the electron transport layer 30, improve the problem of quenching of the quantum dot light-emitting layer 50 caused by the surface defects of the electron transport layer 30, and improve the performance of the display substrate.

[0088] In one embodiment, as Figure 3 shown, the swelling layer 40 is provided with a hollowed-out portion, and part of the electron transport layer 30 is filled in the hollowed-out portion. The part of the electron transport layer 30 located in the hollowed-out portion is in direct contact with the quantum dot light-emitting layer 50.

[0089] Further, in the horizontal direction, the expansion coefficient of the expansion layer 40 is greater than that of the electron transport layer 30. With such a setting, when the display substrate is working, the expansion size of the expansion layer 40 in the horizontal direction is greater than that of the electron transport layer 30 in the horizontal direction. Generally, the expansion size of the electron transport layer 30 in the horizontal direction can be ignored. Due to the increase in the size of the expansion layer 40 in the horizontal direction, the part of the electron transport layer 30 located in the hollow part of the expansion layer 40 is squeezed by the expansion layer 40, making the atomic arrangement of the part of the electron transport layer 30 located in the hollow part more compact, and the gap between adjacent atoms becomes narrower. During the electron transport process, when electrons are transmitted from the part of the electron transport layer 30 located in the hollow part of the expansion layer to the quantum dot light-emitting layer 50, since the distance between atoms in the part of the electron transport layer 30 located in the hollow part becomes narrower, the electron transport channel becomes narrower, and the electron transport efficiency decreases.

[0090] Further, in the film stack direction of the display substrate, the expansion coefficient of the expansion layer 40 is greater than that of the electron transport layer 30. With such a setting, when the display substrate is working, the expansion layer 40 expands in the film stack direction of the display substrate, that is, the size of the expansion layer 40 increases in the film stack direction of the display substrate. The part of the electron transport layer 30 located in the hollow part is stretched along with the expansion layer 40, and the thickness of this part of the electron transport layer 30 increases. Furthermore, the thickness of the part of the electron transport layer 30 opposite to the hollow part increases, and the transport distance of electrons during the transmission from this part of the electron transport layer 30 to the quantum dot light-emitting layer 50 increases, which can reduce the electron transport efficiency; and during the process of electrons transmitting from the part of the electron transport layer 30 opposite to the expansion layer 40 to the quantum dot light-emitting layer 50, when the electrons are transmitted to the surface of the expansion layer 40 facing the substrate 10, they need to bypass the surface of the expansion layer 40 facing the substrate 10 to be transmitted to the quantum dot light-emitting layer 50, so the electron transport distance increases, which can reduce the electron transport efficiency.

[0091] In one embodiment, in the horizontal direction, the expansion coefficient of the expansion layer 40 is greater than that of the electron transport layer 30, and in the film stack direction of the display substrate, the expansion coefficient of the expansion layer 40 is greater than that of the electron transport layer 30. With such a setting, during the working process of the display substrate, the expansion sizes of the expansion layer 40 in the horizontal direction and the film stack direction are both large, which can not only narrow the electron transport channel but also increase the transport distance of electrons to the quantum dot light-emitting layer 50 in the film stack direction, effectively reducing the electron transport efficiency and effectively improving the balance of electrons and holes injected into the quantum dot light-emitting layer 50.

[0092] In one embodiment, the thickness range of the expansion layer 40 may be 10 nm to 100 nm. If the thickness of the expansion layer 40 is too small, the deformation after expansion of the expansion layer 40 is not obvious, and it cannot effectively compress the electron transport channel or increase the electron transport distance. If the thickness of the expansion layer 40 is large, it will result in a large thickness of the electron transport layer 30, which may reduce the electron transport efficiency too much and affect the light-emitting efficiency of the quantum dot light-emitting layer 50. Setting the thickness of the expansion layer 40 within the above range can reduce the electron transport efficiency and reduce the heat generated during the operation of the display substrate, while not affecting the normal device performance of the display substrate. The thickness of the expansion layer 40 may be, for example, 10 nm, 30 nm, 60 nm, 90 nm, 100 nm, etc.

[0093] In one embodiment, the volume ratio range of the expansion layer 40 to the electron transport layer 30 may be 40% to 60%. If the volume ratio of the expansion layer 40 to the electron transport layer 30 is too small, it cannot effectively compress the electron transport channel or increase the electron transport distance. If the volume ratio of the expansion layer 40 to the electron transport layer 30 is too large, it may reduce the electron transport efficiency too much, resulting in too few electrons injected into the quantum dot light-emitting layer, thereby affecting the light-emitting efficiency of the quantum dot light-emitting layer. Setting the volume ratio of the expansion layer 40 to the electron transport layer 30 within the above range can reduce the heat generated during the operation of the display substrate while not affecting the device performance of the display substrate. The volume ratio of the expansion layer 40 to the electron transport layer 30 may be, for example, 40%, 45%, 50%, 55%, 60%, etc.

[0094] In one embodiment, the expansion layer 40 includes a plurality of spaced-apart expansion structures, and part of the electron transport layer 30 is filled between adjacent expansion structures. Part of the electron transport layer 30 located between the expansion structures is in direct contact with the quantum dot light-emitting layer 50.

[0095] Further, the expansion coefficient of the expansion layer 40 in the horizontal direction is greater than that of the electron transport layer 30. With such a setting, when the display substrate is working, the expansion size of the expansion layer 40 in the horizontal direction is greater than that of the electron transport layer 30 in the horizontal direction. Generally, the expansion of the electron transport layer 30 in the horizontal direction can be ignored. Since the size of the expansion layer 40 increases in the horizontal direction, the expansion layer 40 expands. The part of the electron transport layer 30 located between the expansion structures is squeezed by the expansion layer 40, making the atomic arrangement of the part of the electron transport layer 30 located between the expansion structures more compact and the gap between adjacent atoms narrower. During the process of electron transport, when electrons are transported through the part of the electron transport layer 30 located between the expansion structures to the quantum dot light-emitting layer 50, since the distance between atoms in the part of the electron transport layer 30 located between the expansion structures becomes narrower, the electron transport channel is compressed and narrowed, reducing the electron transport efficiency.

[0096] Further, the expansion coefficient of the expansion layer 40 in the film layer stacking direction of the display substrate is greater than that of the electron transport layer 30. With such a setting, when the display substrate is working, the expansion layer 40 expands in the film layer stacking direction of the display substrate, that is, the size of the expansion layer increases in the film layer stacking direction of the display substrate. The part of the electron transport layer 30 located between the expansion structures is stretched along with the expansion layer 40, and the thickness of this part of the electron transport layer 30 increases. Furthermore, the thickness of the part of the electron transport layer 30 opposite to the expansion structure increases. The transport distance of electrons increases during the process of passing through this part of the electron transport layer 30 to the quantum dot light-emitting layer 50, which can reduce the electron transport efficiency. And during the process of electrons passing through the part of the electron transport layer 30 opposite to the expansion layer 40 to the quantum dot light-emitting layer 50, when the electrons are transported to the surface of the expansion layer 40 facing the substrate 10, they need to bypass the surface of the expansion layer 40 facing the substrate 10 to be transported to the quantum dot light-emitting layer 50, so the electron transport distance increases, reducing the electron transport efficiency.

[0097] In one embodiment, the expansion coefficient of the expansion layer 40 in the horizontal direction is greater than that of the electron transport layer 30, and the expansion coefficient of the expansion layer 40 in the film layer stacking direction of the display substrate is greater than that of the electron transport layer 30. With such a setting, during the working process of the display substrate, the expansion sizes of the expansion layer 40 in both the horizontal direction and the film layer stacking direction are relatively large. This can not only narrow the electron transport channel but also increase the transport distance of electrons to the quantum dot light-emitting layer 50 in the film layer stacking direction, effectively reducing the electron transport efficiency and effectively improving the balance of electrons and holes injected into the quantum dot light-emitting layer 50.

[0098] In one embodiment, the thickness range of the expansion layer 40 may be 10 nm to 100 nm. When the thickness of the expansion layer 40 is too small, the deformation after expansion of the expansion layer 40 is not obvious, and it cannot effectively compress the electron transport channel or increase the electron transport distance. If the thickness of the expansion layer 40 is large, it will cause the thickness of the electron transport layer 30 to be large, which may reduce the electron transport efficiency too much and affect the light-emitting efficiency of the quantum dot light-emitting layer 50. Setting the thickness of the expansion layer 40 within the above range can reduce the electron transport efficiency and reduce the heat generated during the operation of the display substrate, while not affecting the normal device performance of the display substrate. The thickness of the expansion layer 40 may be, for example, 10 nm, 30 nm, 60 nm, 90 nm, 100 nm, etc.

[0099] In one embodiment, the volume ratio range of the expansion layer 40 to the electron transport layer 30 may be 40% to 60%. When the volume ratio of the expansion layer 40 to the electron transport layer 30 is too small, it cannot effectively compress the electron transport channel or increase the electron transport distance. If the volume ratio of the expansion layer 40 to the electron transport layer 30 is too large, it may reduce the electron transport efficiency too much, resulting in too few electrons injected into the quantum dot light-emitting layer, and thus affecting the light-emitting efficiency of the quantum dot light-emitting layer. Setting the volume ratio of the expansion layer 40 to the electron transport layer 30 within the above range can reduce the heat generated during the operation of the display substrate while not affecting the device performance of the display substrate. The volume ratio of the expansion layer 40 to the electron transport layer 30 may be, for example, 40%, 45%, 50%, 55%, 60%, etc.

[0100] In one embodiment, as Figure 4 shown, the expansion layer 40 is provided with a hollowed-out portion, and part of the quantum dot light-emitting layer 50 is filled in the hollowed-out portion. The quantum dot light-emitting layer 50 located in the hollowed-out portion is in direct contact with the electron transport layer 30.

[0101] In one embodiment, the expansion coefficient of the expansion layer 40 in the film layer stacking direction of the display substrate is greater than that of the electron transport layer 30. With such a setting, when the display substrate is working, the size of the expansion layer 40 expanding in the film layer stacking direction of the display substrate is larger. The portion of the electron transport layer 30 opposite to the expansion layer 40 is extruded by the force exerted on it by the expansion layer 40. As a result, the portion of the electron transport layer 30 opposite to the hollow portion is extruded into the hollow portion, that is, the thickness of the portion of the electron transport layer 30 opposite to the hollow portion increases, and the transport distance of electrons during the process of passing through this portion of the electron transport layer and transmitting to the quantum dot light-emitting layer 50 increases, which can reduce the electron transport efficiency. Moreover, when electrons pass through the portion of the electron transport layer 30 opposite to the expansion layer 40 and transmit to the quantum dot light-emitting layer 50, the electrons need to bypass the surface of the expansion layer 40 facing the substrate 10 when transmitting to the surface of the expansion layer 40 facing the substrate 10 before they can transmit to the quantum dot light-emitting layer 50, so the transport distance of the electrons increases, which can reduce the electron transport efficiency.

[0102] In one embodiment, the expansion layer 40 includes a plurality of expansion structures arranged at intervals, and part of the quantum dot light-emitting layer 50 is filled between adjacent expansion structures. The quantum dot light-emitting layer 50 located between the expansion structures is in direct contact with the electron transport layer 30.

[0103] In one embodiment, the expansion coefficient of the expansion layer 40 in the film layer stacking direction of the display substrate is greater than that of the electron transport layer 30. With such a setting, when the display substrate is working, the size of the expansion layer 40 expanding in the film layer stacking direction of the display substrate is larger. The portion of the electron transport layer 30 opposite to the expansion layer 40 is extruded by the force exerted on it by the expansion layer 40. As a result, the portion of the electron transport layer 30 opposite to the region between adjacent expansion structures is extruded into the region between the expansion structures, that is, the thickness of the portion of the electron transport layer 30 opposite to the region between adjacent expansion structures increases, and the transport distance of electrons during the process of passing through this portion of the electron transport layer and transmitting to the quantum dot light-emitting layer 50 increases, which can reduce the electron transport efficiency. Moreover, when electrons pass through the portion of the electron transport layer 30 opposite to the expansion layer 40 and transmit to the quantum dot light-emitting layer 50, the electrons need to bypass the surface of the expansion layer 40 facing the substrate 10 when transmitting to the surface of the expansion layer 40 facing the substrate 10 before they can transmit to the quantum dot light-emitting layer 50, so the transport distance of the electrons increases, which can reduce the electron transport efficiency.

[0104] In one embodiment, as Figure 5As shown, the orthographic projection of the expansion layer 40 on the substrate 10 coincides with the orthographic projection of the electron transport layer 30 on the substrate 10, and the thickness range of the expansion layer 40 is 5 nm to 10 nm; in the film layer stacking direction of the display substrate, the expansion coefficient of the expansion layer 40 is greater than that of the electron transport layer 30.

[0105] In this embodiment, the expansion layer 40 entirely covers the electron transport layer 30. According to the tunneling effect, when the thickness of the expansion layer 40 is small, electrons can tunnel through the expansion layer 40 and enter the quantum dot light-emitting layer 50. Since the expansion coefficient of the expansion layer 40 in the film layer stacking direction of the display substrate is greater than that of the electron transport layer 30, when the display substrate is working, the expansion layer 40 expands in the film layer stacking direction of the display substrate, the thickness of the expansion layer 40 increases, thereby increasing the distance from the cathode layer 20 to the quantum dot light-emitting layer 50, increasing the electron transport distance, reducing the electron transport efficiency, and contributing to the balance of carriers injected into the quantum dot light-emitting layer 50. By setting the thickness range of the expansion layer 40 to be 5 nm to 10 nm, it can be avoided that the thickness of the expansion layer 40 after expansion is too small to effectively increase the distance between the cathode layer 20 and the quantum dot light-emitting layer 50, and thus the electron transport efficiency cannot be effectively reduced. It can also be avoided that the thickness of the expansion layer 40 is too large, resulting in electrons not being able to enter the electron transport layer 30 through the expansion layer 40.

[0106] The following takes Figure 1 the embodiment shown as an example to calculate the influence of the expansion layer 40 on the electron transport efficiency. In this embodiment, the expansion layer 40 includes a plurality of spherical expansion structures arranged at intervals. The material of the expansion structure is polystyrene, and the materials of the first electron transport film layer 301 and the second electron transport film layer 302 are both zinc oxide.

[0107] When the display substrate is not working, the total thickness of the first electron transport film layer 301, the second electron transport film layer 302, and the expansion layer 40 in the film layer stacking direction is 60 nm, and the size of one side of the first electron transport film layer 301 in the horizontal direction is 100 μm. The diameter of the expansion structure is 50 nm, and the projected area of the expansion structures arranged in the direction of this side of the first electron transport film layer 301 on the substrate 10 is 50% of the projected area of the first electron transport film layer 301 on the substrate 10, that is, the sum of the maximum sizes of the expansion structures in the extension direction of this side of the first electron transport film layer 301 is 50 μm, that is, there are 1000 expansion structures arranged in the expansion layer 40 in the extension direction of one side of the first electron transport film layer 301, and the sum of the gaps between adjacent expansion structures in the extension direction of this side of the first electron transport film layer 301 is 50 μm. The thermal expansion coefficient of the expansion structure is 250×10 -6 m / mK.

[0108] After the display substrate starts to work, when the temperature of the display substrate rises from 20°C to 120°C, the size of each expansion structure increases by 1.25 nm in the horizontal direction. Since the increase in the thickness of the first electron transport film layer 301 and the second electron transport film layer 302 is negligible, the total thickness of the first electron transport film layer 301, the second electron transport film layer 302, and the expansion layer 40 in the reverse direction of the film stack increases by 1.25 nm, and the percentage increase relative to the total thickness when the display substrate is not working is 1.25 / 60≈2.1%. At the same time, the size of each expansion structure also increases by 1.25 nm in the horizontal direction. The total size of 1000 expansion structures arranged in the extension direction of one side of the first electron transport film layer 301 increases by 1.25 μm in the horizontal direction, and the size of the electron transport channel compressed in the horizontal direction is 1.25 μm. It can be calculated that the percentage of the electron transport channel compressed in the horizontal direction is 1.25 / 50 = 2.5%.

[0109] As can be seen from the above, after the display substrate starts to work, when the temperature of the display substrate rises from 20°C to 120°C, relative to when the display substrate is not working, the electron transport distance increases to 102.1%, and the size of the electron transport channel in the horizontal direction decreases to 99.75%. According to the resistance calculation formula R = ρL / S, it can be calculated that the resistance in the electron transport process increases by about 4.7%, that is, the electron transport efficiency decreases by about 4.7%. It can be seen that by setting the expansion layer 40 in the embodiment of the present application, the electron transport efficiency can be effectively reduced.

[0110] The embodiment of the present application also provides a method for manufacturing a display substrate, and the manufacturing method is used to manufacture the display substrate as Figure 1 shown. The method for manufacturing the display substrate includes the following steps:

[0111] First, provide a substrate.

[0112] Subsequently, form a cathode layer on the substrate.

[0113] Subsequently, form a first electron transport film layer on the cathode layer. The first electron transport film layer can be formed by depositing zinc oxide material using a magnetron sputtering process. The thickness of the part of the first electron transport film layer corresponding to different color sub-pixels can be different.

[0114] Subsequently, form an expansion layer on the first electron transport film layer. When the expansion layer includes a plurality of expansion structures, an expansion material layer covering the first electron transport film layer can be deposited on the first electron transport film layer first, and then the expansion material layer is etched to obtain an expansion layer including a plurality of expansion structures; alternatively, a mask can be set on the first electron transport film layer first, and then an expansion layer including a plurality of expansion structures is formed on the first electron transport film layer through the openings of the mask.

[0115] Subsequently, a second electron transport film layer is formed on the swelling layer. The second electron transport film layer can be formed by depositing zinc oxide material using a magnetron sputtering process.

[0116] Subsequently, a quantum dot light-emitting layer is formed on the second electron transport film layer. The quantum dot light-emitting layer can be formed by an inkjet printing process.

[0117] Subsequently, a hole transport layer and a hole injection layer are sequentially formed on the quantum dot light-emitting layer. The hole transport layer and the hole injection layer can be formed by an evaporation process.

[0118] Subsequently, an anode layer is formed on the hole injection layer. The anode layer can be formed by a magnetron sputtering process.

[0119] The method for preparing a display substrate provided by the embodiment of the present application and the display substrate prepared by using this method belong to the same inventive concept, and the description of relevant details and beneficial effects will not be repeated.

[0120] The embodiment of the present application also provides another method for preparing a display substrate, and the preparation method can also be used to prepare a display substrate as Figure 3 shown. The method for preparing the display substrate includes the following steps:

[0121] First, a substrate is provided.

[0122] Subsequently, a cathode layer is formed on the substrate.

[0123] Subsequently, an electron transport layer is formed on the cathode layer. The electron transport film layer can be formed by depositing zinc oxide material using a magnetron sputtering process. The thickness of the part of the electron transport film layer corresponding to different color sub-pixels can be different.

[0124] Subsequently, the surface of the electron transport layer is etched to form a groove.

[0125] Subsequently, a swelling layer is formed on the electron transport film layer, and the swelling layer is located in the groove of the electron transport layer.

[0126] Subsequently, a quantum dot light-emitting layer is formed on the electron transport film layer. The quantum dot light-emitting layer can be formed by an inkjet printing process.

[0127] Subsequently, a hole transport layer and a hole injection layer are sequentially formed on the quantum dot light-emitting layer. The hole transport layer and the hole injection layer can be formed by an evaporation process.

[0128] Subsequently, an anode layer is formed on the hole injection layer. The anode layer can be formed by a magnetron sputtering process.

[0129] The method for preparing a display substrate provided in the embodiment of the present application and the display substrate prepared by the method belong to the same inventive concept, and the description of the relevant details and beneficial effects will not be repeated here.

[0130] An embodiment of the present application further provides a display device, which includes the display substrate described in any of the above embodiments.

[0131] In one embodiment, the display device is a display panel, which includes the display substrate described in any of the above embodiments and an encapsulation layer located on a side of the display substrate away from the substrate, and the encapsulation layer may be a thin film encapsulation layer.

[0132] In one embodiment, the display panel further includes a cover plate located on a side of the encapsulation layer facing away from the substrate, and the cover plate may be a glass cover plate.

[0133] In one embodiment, the display device includes a display panel and a housing, and the display panel is disposed in the housing.

[0134] In one embodiment, the display device further includes a driver and a power supply circuit, wherein the driver is used to provide a driving signal for driving the pixel circuit, and the power supply circuit is used to supply power to the display panel.

[0135] The display device provided in the embodiment of the present application may be, for example, a mobile phone, a tablet computer, a television, a laptop computer, a vehicle-mounted device, or any other device with a display function.

[0136] The above is only a preferred embodiment of the present application and does not constitute any form of limitation to the present application. Although the present application has been disclosed as a preferred embodiment as above, it is not intended to limit the present application. Any technician familiar with the profession can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present application. However, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present application without departing from the content of the technical solution of the present application still falls within the scope of the technical solution of the present application.

[0137] The disclosure of this patent document contains material that is subject to copyright protection. The copyright is reserved by the copyright owner. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure as it exists in the official records and files of the Patent and Trademark Office.

Claims

1. A display substrate, characterized in that, The display substrate comprises: substrate; a cathode layer and an anode layer located on the substrate; A quantum dot light-emitting layer, located between the cathode layer and the anode layer; An electron transport layer, located between the cathode layer and the quantum dot light-emitting layer; The expansion layer is located between at least a portion of the electron transport layer and the quantum dot light-emitting layer; the expansion layer is configured to expand when the display substrate is working, and the expansion coefficient of the expansion layer is greater than the expansion coefficient of the electron transport layer.

2. The display substrate according to claim 1, wherein The material of the expansion layer includes at least one of a thermal expansion material and an electrical expansion material.

3. The display substrate according to claim 2, wherein The thermal expansion material includes at least one of a semiconductor material, a polymer material and a thermal isomerization material; the electrical expansion material includes at least one of an electroactive polymer material and a piezoelectric material.

4. The display substrate according to claim 1, wherein The electron transport layer includes a first electron transport film layer and a second electron transport film layer located on a side of the first electron transport film layer away from the substrate, and the expansion layer is located between the first electron transport film layer and the second electron transport film layer.

5. The display substrate according to claim 4, wherein The expansion layer is provided with a plurality of hollow portions, or the expansion layer includes a plurality of expansion structures arranged at intervals; the expansion coefficient of the expansion layer in the horizontal direction is greater than the expansion coefficient of the electron transport layer, and / or the expansion coefficient of the expansion layer in the film layer stacking direction of the display substrate is greater than the expansion coefficient of the electron transport layer.

6. The display substrate according to claim 4, wherein The orthographic projection of the expansion layer on the substrate coincides with the orthographic projection of the first electron transport film layer on the substrate, and the thickness of the expansion layer ranges from 5nm to 10nm; the expansion coefficient of the expansion layer in the film layer stacking direction of the display substrate is greater than the expansion coefficient of the electron transport layer in the film layer stacking direction.

7. The display substrate according to claim 1, wherein The expansion layer is located between the electron transport layer and the quantum dot light-emitting layer, and the expansion layer is in contact with the quantum dot light-emitting layer.

8. The display substrate according to claim 7, wherein The expansion layer is provided with a hollow portion, and part of the electron transport layer is filled in the hollow portion; or the expansion layer includes a plurality of expansion structures arranged at intervals, and part of the electron transport layer is filled between adjacent expansion structures; the expansion coefficient of the expansion layer in the horizontal direction is greater than the expansion coefficient of the electron transport layer, and / or the expansion coefficient of the expansion layer in the film layer stacking direction of the display substrate is greater than the expansion coefficient of the electron transport layer.

9. The display substrate according to claim 7, wherein The expansion layer is provided with a hollow portion, and part of the quantum dot light-emitting layer is filled in the hollow portion; or the expansion layer includes a plurality of expansion structures arranged at intervals, and part of the quantum dot light-emitting layer is filled between adjacent expansion structures; the expansion coefficient of the expansion layer in the film layer stacking direction of the display substrate is greater than the expansion coefficient of the electron transport layer.

10. The display substrate according to claim 7, wherein The orthographic projection of the expansion layer on the substrate coincides with the orthographic projection of the electron transport layer on the substrate, and the thickness of the expansion layer ranges from 5nm to 10nm; the expansion coefficient of the expansion layer in the film layer stacking direction of the display substrate is greater than the expansion coefficient of the electron transport layer.

11. A display device, characterized in that, The display device comprises the display substrate according to any one of claims 1 to 10.

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