Display substrate and manufacturing method therefor, and display apparatus

Abstract

A display substrate, a manufacturing method therefor, and a display apparatus. The display substrate comprises at least one sub-pixel (20); the at least one sub-pixel (20) comprises a first electrode (11), a light-emitting functional layer (12), and a second electrode (13), which are sequentially stacked in the direction away from a substrate (101); the light-emitting functional layer (12) comprises at least one light-emitting unit, the at least one light-emitting unit comprising a light-emitting layer, a hole transport layer, and an electron transport layer; the hole transport layer is located between the light-emitting layer and the first electrode (11), the hole mobility of the hole transport layer being greater than or equal to 7*10-6cm2 / Vs and less than or equal to 5*10-4cm2 / Vs; the electron transport layer is located between the light-emitting layer and the second electrode (13), the electron mobility of the electron transport layer being greater than or equal to 1*10-6cm2 / Vs and less than or equal to 1*10-4cm2 / Vs.

Description

Display substrate, preparation method thereof and display device

[0001] The present application claims priority to the Chinese patent application No. 202411017152.2, filed on July 26, 2024, and entitled "Display substrate, preparation method thereof and display device", the contents of which are to be understood as incorporated herein by reference. TECHNICAL FIELD

[0002] The present application relates to the technical field of display, in particular to a display substrate, a preparation method thereof and a display device. BACKGROUND

[0003] Micro Organic Light-Emitting Diode (Micro-OLED) is a micro display developed in recent years, and silicon-based OLED is one of them. Silicon-based OLED not only can realize active addressing of pixels, but also can realize preparation of pixel driving circuit structure on silicon-based substrate, which is beneficial to reduce system volume and realize light weight. Silicon-based OLED is prepared by mature Complementary Metal Oxide Semiconductor (CMOS) integrated circuit process, has the advantages of small volume, high resolution (Pixels Per Inch, PPI), high refresh rate, etc., and is widely used in Virtual Reality (VR) or Augmented Reality (AR) near-eye display field. SUMMARY

[0004] The following is a summary of the subject matter of the detailed description herein. This summary is not intended to limit the scope of the claims.

[0005] In one aspect, the present disclosure provides a display substrate, comprising at least one sub-pixel, the at least one sub-pixel comprising a first electrode, a light-emitting functional layer and a second electrode which are sequentially stacked along a direction away from a substrate; the light-emitting functional layer comprising at least one light-emitting unit, the at least one light-emitting unit comprising a light-emitting layer, a hole transport layer and an electron transport layer, the hole transport layer being located between the light-emitting layer and the first electrode, the hole transport layer having a hole mobility greater than or equal to 7*10 -6 cm 2 / Vs being less than or equal to 5*10 -4 cm 2 / Vs, the electron transport layer being located between the light-emitting layer and the second electrode, the electron transport layer having an electron mobility greater than or equal to 1*10 -6 cm2 Vs is less than or equal to 1*10 -4 cm 2 Vs.

[0006] In an exemplary embodiment, the hole transport layer has a hole mobility greater than or equal to 1*10 -5 cm 2 Vs is less than or equal to 1*10 -4 cm 2 Vs.

[0007] In an exemplary embodiment, the electron transport layer has an electron mobility greater than or equal to 1*10 -5 cm 2 Vs is less than or equal to 8*10 -5 cm 2 Vs.

[0008] In an exemplary embodiment, the light-emitting functional layer includes a first light-emitting unit and a second light-emitting unit stacked in order along a direction away from the substrate, and a charge generation layer disposed between the first light-emitting unit and the second light-emitting unit, the first light-emitting unit includes a first light-emitting layer, a first hole transport layer, and a first electron transport layer, the first hole transport layer is disposed between the first light-emitting layer and the first electrode, the first hole transport layer has a hole mobility greater than or equal to 7*10 -6 cm 2 Vs is less than or equal to 5*10 -4 cm 2 Vs, the first electron transport layer is disposed between the first light-emitting layer and the second electrode, the first electron transport layer has an electron mobility greater than or equal to 1*10 -6 cm 2 Vs is less than or equal to 1*10 -4 cm 2 Vs; the second light-emitting unit includes a second light-emitting layer, a second hole transport layer, and a second electron transport layer, the second hole transport layer is disposed between the second light-emitting layer and the first electrode, the second hole transport layer has a hole mobility greater than or equal to 7*10 -6 cm 2 Vs is less than or equal to 5*10 -4 cm 2 Vs, the second electron transport layer is disposed between the second light-emitting layer and the second electrode, the second electron transport layer has an electron mobility greater than or equal to 1*10 -6 cm 2 Vs is less than or equal to 1*10 -4 cm 2 Vs.

[0009] In an exemplary embodiment, one of the first light-emitting layer and the second light-emitting layer emits yellow light, and the other of the first light-emitting layer and the second light-emitting layer emits blue light.

[0010] In an exemplary embodiment, one of the first light-emitting layer and the second light-emitting layer is a yellow light-emitting layer, and the other of the first light-emitting layer and the second light-emitting layer is a blue light-emitting layer; or one of the first light-emitting layer and the second light-emitting layer comprises a first sub-light-emitting layer and a second sub-light-emitting layer arranged in sequence along a direction away from the substrate, one of the first sub-light-emitting layer and the second sub-light-emitting layer is a red light-emitting layer, and the other of the first sub-light-emitting layer and the second sub-light-emitting layer is a green light-emitting layer, and the other of the first light-emitting layer and the second light-emitting layer is a blue light-emitting layer; or one of the first light-emitting layer and the second light-emitting layer comprises a first sub-light-emitting layer and a second sub-light-emitting layer arranged in sequence along a direction away from the substrate, one of the first sub-light-emitting layer and the second sub-light-emitting layer is a yellow light-emitting layer, and the other of the first sub-light-emitting layer and the second sub-light-emitting layer is a green light-emitting layer and a red light-emitting layer stacked with each other, and the other of the first light-emitting layer and the second light-emitting layer is a blue light-emitting layer.

[0011] In an exemplary embodiment, the light-emitting functional layer further comprises a first hole injection layer, a first functional layer, a first hole blocking layer, a second functional layer, a second hole blocking layer, and an electron injection layer, the first hole injection layer is located on a side of the first hole transport layer close to the substrate and in contact with the first electrode; the first functional layer is located on a side of the first hole transport layer away from the substrate and in contact with the first light-emitting layer; the first hole blocking layer is arranged on a side of the first electron transport layer close to the substrate and in contact with the first light-emitting layer; the second functional layer is located on a side of the second hole transport layer away from the substrate and in contact with the second light-emitting layer; the second hole blocking layer is arranged on a side of the second electron transport layer close to the substrate and in contact with the second light-emitting layer; and the electron injection layer is arranged on a side of the second electron transport layer away from the substrate and in contact with the second electrode.

[0012] In an exemplary embodiment, the sum of the thicknesses of the light-emitting functional layer and the second electrode is 200 nanometers to 250 nanometers.

[0013] In an exemplary embodiment, a pixel definition layer is further included, which is disposed on a side of the first electrode away from the substrate, the pixel definition layer is provided with a pixel opening exposing at least part of the first electrode, the pixel definition layer is provided with an undercut structure, at least part of the light-emitting functional layer covers the undercut structure, and at least part of the light-emitting functional layer forms a recessed area at the undercut structure.

[0014] In an exemplary embodiment, the pixel definition layer comprises a first definition layer, a second definition layer and a third definition layer stacked in sequence along a direction away from the substrate, at least part of the first definition layer covers an edge region of a side surface of the first electrode away from the substrate, and a side surface of the first electrode, the first definition layer has a first side wall close to a middle region of the pixel opening, the second definition layer has a second side wall close to the middle region of the pixel opening, the third definition layer has a third side wall close to the middle region of the pixel opening, the first side wall is connected to the side surface of the first electrode away from the substrate, the first side wall respectively protrudes compared with the second side wall and the third side wall, and the third side wall protrudes compared with the second side wall, forming the undercut structure.

[0015] In an exemplary embodiment, the thickness of the first definition layer is 50 angstroms to 500 angstroms, the thickness of the second definition layer is 300 angstroms to 1000 angstroms, and the thickness of the third definition layer is 50 angstroms to 500 angstroms.

[0016] In an exemplary embodiment, the first electrode comprises a first conductive pattern, a second conductive pattern and a third conductive pattern stacked in sequence along a direction away from the substrate, the thickness of the first conductive pattern and the third conductive pattern is 70 angstroms to 100 angstroms, and the thickness of the second conductive pattern is 800 angstroms to 1200 angstroms.

[0017] In an exemplary embodiment, the first electrode comprises a first conductive pattern, a second conductive pattern, an insulating medium layer and a third conductive pattern stacked in sequence along a direction away from the substrate, the insulating medium layer is provided with a via, and the third conductive pattern is connected to the second conductive pattern through the via.

[0018] In another aspect, the present disclosure further provides a preparation method of a display substrate, comprising:

[0019] forming a first electrode, a light-emitting functional layer and a second electrode in sequence along a direction away from the substrate;

[0020] The light-emitting functional layer includes at least one light-emitting unit, the at least one light-emitting unit includes a light-emitting layer, a hole transport layer and an electron transport layer, the hole transport layer is located between the light-emitting layer and the first electrode, the hole transport layer has a hole mobility greater than or equal to 7*10 -6 cm 2 Vs less than or equal to 5*10 -4 cm 2 Vs, the electron transport layer is located between the light-emitting layer and the second electrode, the electron transport layer has an electron mobility greater than or equal to 1*10 -6 cm 2 Vs less than or equal to 1*10 -4 cm 2 Vs.

[0021] In another aspect, the display substrate is used in a display device.

[0022] Other aspects can become apparent from a review of the drawings and detailed description. BRIEF DESCRIPTION OF DRAWINGS

[0023] The accompanying drawings are included to provide a further understanding of the present technology, and constitute a part of this specification. The drawings illustrate embodiments of the present technology and, together with the detailed description, serve to explain the principles of the present technology. The drawings and detailed description do not necessarily include all customary technical features of the present technology.

[0024] FIG. 1 is a structural schematic diagram of a display device;

[0025] FIG. 2 is a planar structural schematic diagram of a display area in a display device;

[0026] FIG. 3 is a cross-sectional structural schematic diagram of a display area of a display device;

[0027] FIG. 4 is a cross-sectional structural schematic diagram of an edge area of a sub-pixel in a display substrate according to an embodiment of the present disclosure;

[0028] FIG. 5 is a cross-sectional structural schematic diagram of a first electrode and a pixel definition layer in a display substrate according to an embodiment of the present disclosure;

[0029] FIG. 6 is a cross-sectional structural schematic diagram of another first electrode and a pixel definition layer in a display substrate according to an embodiment of the present disclosure;

[0030] FIG. 7 is a structural schematic diagram of a light-emitting functional layer in a display substrate according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0031] In order to make the objects, technical solutions and advantages of the present disclosure clearer, the following will be used to specifically explain the embodiments of the present disclosure with reference to the drawings. It should be noted that the embodiments can be implemented in a variety of different forms. Those skilled in the art can easily understand that the manner and content can be changed into various forms without departing from the spirit and scope of the present disclosure. Therefore, the present disclosure should not be interpreted as being limited to the content described in the following embodiments. The embodiments in the present disclosure and the features in the embodiments can be combined with each other arbitrarily without conflict.

[0032] The proportions of the drawings in the present disclosure can be used as a reference in the actual process, but are not limited thereto. For example, the width-length ratio of the channel, the thickness and spacing of each film layer, and the width and spacing of each signal line can be adjusted according to actual needs. The number of pixels in the display device and the number of sub-pixels in each pixel are also not limited to the number shown in the drawings. The drawings described in the present disclosure are only schematic structural diagrams, and one embodiment of the present disclosure is not limited to the shapes or values shown in the drawings.

[0033] In the present specification, ordinal numbers such as "first", "second", "third", and the like are provided to avoid confusion of components, and are not intended to be limited in terms of quantity.

[0034] In the present specification, for the convenience of explanation, words indicating the orientation or positional relationship such as "middle", "upper", "lower", "front", "rear", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like are used to explain the positional relationship of the components with reference to the drawings, and are only for the convenience of describing the present specification and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present disclosure. The positional relationship of the components is appropriately changed according to the direction of describing each component. Therefore, it is not limited to the words described in the specification, and can be appropriately changed according to the situation.

[0035] In the present specification, unless otherwise explicitly specified and limited, the terms "mount", "connect", "connection" should be understood in a broad sense. For example, it can be fixedly connected, or detachably connected, or integrally connected; it can be mechanically connected, or electrically connected; it can be directly connected, or indirectly connected through an intermediate part, or the communication inside two elements. Those skilled in the art can understand the specific meaning of the above terms in the present disclosure according to the specific circumstances.

[0036] In this specification, a transistor means an element including at least three terminals of a gate electrode, a drain electrode, and a source electrode. The transistor has a channel region between the drain electrode (a drain electrode terminal, a drain region, or a drain electrode) and the source electrode (a source electrode terminal, a source region, or a source electrode), and current can flow through the drain electrode, the channel region, and the source electrode. Note that, in this specification, the channel region means a region where current flows mainly.

[0037] In this specification, the first terminal can be a drain electrode and the second terminal can be a source electrode, or the first terminal can be a source electrode and the second terminal can be a drain electrode. In the case of using a transistor having an opposite polarity or in the case where the direction of current changes in circuit operation, the functions of the "source electrode" and the "drain electrode" are sometimes interchanged with each other. Thus, in this specification, the "source electrode" and the "drain electrode" can be interchanged with each other, and the "source terminal" and the "drain terminal" can be interchanged with each other.

[0038] In this specification, "electrically connected" includes the case where components are connected through an element having some function of electricity. The element having some function of electricity is not particularly limited as long as electric signals can be transmitted and received between components to be connected. Examples of the element having some function of electricity include not only an electrode and a wiring but also a switching element such as a transistor, a resistor, an inductor, a capacitor, and another element having some function.

[0039] In this specification, "parallel" means a state where an angle formed between two straight lines is greater than or equal to -10° and less than or equal to 10°, and thus a state where the angle is greater than or equal to -5° and less than or equal to 5° is also included. In addition, "perpendicular" means a state where an angle formed between two straight lines is greater than or equal to 80° and less than or equal to 100°, and thus a state where the angle is greater than or equal to 85° and less than or equal to 95° is also included.

[0040] In this specification, a "film" and a "layer" can be interchanged with each other. For example, a "conductive layer" can be replaced with a "conductive film". Similarly, an "insulating film" can be replaced with an "insulating layer".

[0041] In this specification, a triangle, a rectangle, a trapezoid, a pentagon, or a hexagon is not strictly a triangle, a rectangle, a trapezoid, a pentagon, or a hexagon, and can be an approximately triangle, a rectangle, a trapezoid, a pentagon, or a hexagon. There can be some small deformation due to a tolerance, a rounded corner, a rounded side, or deformation.

[0042] In this specification, "about" means not strictly limited to the limit and allows a range of values within a process and measurement error.

[0043] The display substrate provided by the embodiments of the present disclosure includes at least one sub-pixel, and the at least one sub-pixel includes a first electrode, a light-emitting functional layer and a second electrode which are sequentially stacked in a direction away from a substrate; the light-emitting functional layer includes at least one light-emitting unit, and the at least one light-emitting unit includes a light-emitting layer, a hole transport layer and an electron transport layer; the hole transport layer is located between the light-emitting layer and the first electrode, the hole mobility of the hole transport layer is greater than or equal to 7*10 -6 cm 2 / Vs, and the electron transport layer is located between the light-emitting layer and the second electrode, the electron mobility of the electron transport layer is greater than or equal to 1*10 -4 cm 2 / Vs, and the electron transport layer is located between the light-emitting layer and the second electrode, the electron mobility of the electron transport layer is greater than or equal to 1*10 -6 cm 2 / Vs, and the electron transport layer is located between the light-emitting layer and the second electrode, the electron mobility of the electron transport layer is greater than or equal to 1*10 -4 cm 2 / Vs.

[0044] FIG. 1 is a structural schematic diagram of a display device. As shown in FIG. 1, the display device can include a timing controller, a data driver, a scan driver, a light-emitting driver and a pixel array. The timing controller is connected with the data driver, the scan driver and the light-emitting driver respectively. The data driver is connected with a plurality of data signal lines (for example, D1 to Dn) respectively, the scan driver is connected with a plurality of scan signal lines (for example, S1 to Sm) respectively, and the light-emitting driver is connected with a plurality of light-emitting control lines (for example, E1 to Eo) respectively. Wherein, n, m and o can be natural numbers. The pixel array can include at least two sub-pixels Pxij, and i and j can be natural numbers. The at least one sub-pixel Pxij can include a pixel circuit and a light-emitting device connected with the pixel circuit. The pixel circuit can be connected with the scan signal line, the light-emitting control line and the data signal line respectively.

[0045] In some example embodiments, the timing controller can provide grayscale values and control signals suitable for the specifications of the data driver to the data driver, can provide clock signals, a scan start signal, and the like suitable for the specifications of the scan driver to the scan driver, and can provide clock signals, an emission stop signal, and the like suitable for the specifications of the light emitting driver to the light emitting driver. The data driver can generate data voltages to be provided to the data signal lines D1, D2, D3, …, and Dn using the grayscale values and the control signals received from the timing controller. For example, the data driver can sample the grayscale values using the clock signals and apply data voltages corresponding to the grayscale values to the data signal lines D1 to Dn in units of pixels. The scan driver can generate scan signals to be provided to the scan signal lines S1, S2, S3, …, and Sm by receiving the clock signals, the scan start signal, and the like from the timing controller. For example, the scan driver can sequentially provide scan signals having on-pulse to the scan signal lines S1 to Sm. For example, the scan driver can be configured in the form of a shift register and can generate the scan signals in a manner that sequentially transfers the scan start signal provided in the form of an on-pulse to a next stage circuit under the control of the clock signals. The light emitting driver can generate light emitting control signals to be provided to the light emitting control lines E1, E2, E3, …, and Eo by receiving the clock signals, the emission stop signal, and the like from the timing controller. For example, the light emitting driver can sequentially provide emission signals having off-pulse to the light emitting control lines E1 to Eo. For example, the light emitting driver can be configured in the form of a shift register and can generate the light emitting control signals in a manner that sequentially transfers the emission stop signal provided in the form of an off-pulse to a next stage circuit under the control of the clock signals.

[0046] FIG. 2 is a schematic diagram of a planar structure of a display region in a display device. As shown in FIG. 2, the display region of the display device can include a plurality of pixel units P arranged in a matrix manner, at least one of the plurality of pixel units P including a first sub-pixel P1 emitting first color light, a second sub-pixel P2 emitting second color light, and a third sub-pixel P3 emitting third color light, the first sub-pixel P1, the second sub-pixel P2, and the third sub-pixel P3 each including a pixel driving circuit and a display light emitting device. The pixel driving circuit in each sub-pixel is connected to a scan signal line and a data signal line, respectively, and is configured to receive a data voltage transmitted by the data signal line under the control of the scan signal line and output a corresponding current to the display light emitting device. The display light emitting device in each sub-pixel is connected to the pixel driving circuit in the sub-pixel, and is configured to emit light of a corresponding brightness in response to the current output by the pixel driving circuit in the sub-pixel.

[0047] In an example embodiment, the first sub-pixel P1 can be a red sub-pixel emitting red (R) light, the second sub-pixel P2 can be a green sub-pixel emitting green (G) light, and the third sub-pixel P3 can be a blue sub-pixel emitting blue (B) light. In an example embodiment, the shape of the sub-pixel can be any one or more of a triangle, a square, a rectangle, a diamond, a trapezoid, a parallelogram, a pentagon, a hexagon, and other polygons, and can be arranged in a horizontal side-by-side manner, a vertical side-by-side manner, an X shape, a cross shape, a pin shape, a square shape, a diamond shape, or a delta shape, without limitation in the present disclosure.

[0048] In an example embodiment, the pixel unit can include four sub-pixels, without limitation in the present disclosure.

[0049] FIG. 3 is a schematic diagram of a cross-sectional structure of a display area of a display device, which can be a cross-sectional view in the A-A’ direction of FIG. 2. The display device shown in FIG. 3 is a structure for realizing full color in a white light + color film manner. As shown in FIG. 3, in a direction perpendicular to the display device, the display device can include a substrate 101, a driving circuit layer 102 disposed on the substrate 101, a light-emitting structure layer 103 disposed on a side of the driving circuit layer 102 away from the substrate 101, a first encapsulation layer 104 disposed on a side of the light-emitting structure layer 103 away from the substrate 101, a color film structure layer 105 disposed on a side of the first encapsulation layer 104 away from the substrate 101, a second encapsulation layer 106 disposed on a side of the color film structure layer 105 away from the substrate 101, and a cover layer 107 disposed on a side of the second encapsulation layer 106 away from the substrate 101. In some possible implementations, the display device can include other film layers, for example, a touch film layer, without limitation in the present disclosure.

[0050] In an example embodiment, the driving circuit layer 102 can be prepared on the substrate 101 by a silicon semiconductor process (for example, a CMOS process), and the driving circuit layer 102 can include a plurality of circuit units, which can at least include a pixel driving circuit, the pixel driving circuit being connected with a scan signal line and a data signal line respectively, and the pixel driving circuit can include a plurality of transistors and a storage capacitor, of which only one transistor is taken as an example in FIG. 4. The transistor can include a control electrode G, a first electrode S, and a second electrode D, which can be connected with corresponding connection electrodes respectively through tungsten metal filled vias (i.e., tungsten vias, W-via), and can be connected with other electrical structures (such as traces, etc.) through the connection electrodes.

[0051] In an example embodiment, the light-emitting structure layer 103 can include a plurality of light-emitting devices, which can at least include a first electrode, a light-emitting functional layer, and a second electrode, the first electrode can be connected to the second electrode D of the transistor through the connecting electrode, the light-emitting functional layer is connected to the first electrode, the second electrode is connected to the light-emitting functional layer, the second electrode is connected to the voltage line, and the light-emitting functional layer emits light under the driving of the first electrode and the second electrode.

[0052] In an example embodiment, the light-emitting functional layer can include at least one light-emitting unit, which can include an emitting layer (EML) and any one or more of a hole injection layer (HIL), a hole transport layer (HTL), an electron blocking layer (EBL), a hole blocking layer (HBL), an electron transport layer (ETL), and an electron injection layer (EIL).

[0053] In an example embodiment, for a light-emitting device emitting white light, some film layers in the light-emitting functional layer of all sub-pixels can be common layers connected together.

[0054] In an example embodiment, the light-emitting device can be a tandem light-emitting device and emit white light, the light-emitting functional layer of the tandem light-emitting device includes at least two light-emitting units stacked and connected in series along the vertical substrate direction, and a charge generation layer is provided between the two adjacent light-emitting units, the charge generation layer generates holes and electrons under the voltage of the first electrode and the second electrode.

[0055] In an example embodiment, the first encapsulation layer 104 and the second encapsulation layer 106 can adopt a thin film encapsulation (TFE) mode, which can ensure that external water vapor cannot enter the light-emitting structure layer, the cover layer 107 can adopt glass or flexible plastic colorless polyimide, etc.

[0056] In an example embodiment, the color filter structure layer 105 can include a black matrix (BM) and a color filter (CF), the position of the color filter can correspond to the position of the light-emitting device, the black matrix can be located between adjacent color filters, and the color filter is configured to filter the white light emitted by the light-emitting device into red (R) light, green (G) light, and blue (B) light, forming red sub-pixels, green sub-pixels, and blue sub-pixels.

[0057] FIG. 4 is a schematic diagram of a cross-sectional structure of an edge region of a sub-pixel in a display substrate according to an embodiment of the present disclosure. In an example embodiment, as shown in FIG. 4, a pixel unit of the display substrate according to an embodiment of the present disclosure includes at least two sub-pixels 20 and a non-sub-pixel region 10 between the adjacent sub-pixels 20, and the sub-pixels 20 of the pixel unit are tandem light-emitting devices that emit white light.

[0058] In an example embodiment, in a direction perpendicular to the display substrate, a sub-pixel 20 in the pixel unit can include a driving circuit layer 102 disposed on a substrate 101, a first insulating layer 14 disposed on a side of the driving circuit layer 102 away from the substrate 101, a second insulating layer 15 disposed on a side of the first insulating layer 14 away from the substrate 101, and a light-emitting structure layer disposed on a side of the second insulating layer 15 away from the substrate 101. The driving circuit layer 102 includes a pixel driving circuit, and the pixel driving circuit includes a transistor. The light-emitting structure layer includes a first electrode 11 disposed on a side of the second insulating layer 15 away from the substrate 101, a light-emitting functional layer 12 disposed on a side of the first electrode 11 away from the substrate 101, and a second electrode 13 disposed on a side of the light-emitting functional layer 12 away from the substrate 101.

[0059] In an example embodiment, the substrate 101 can be a silicon substrate or a glass substrate.

[0060] In an example embodiment, the first insulating layer 14 and the second insulating layer 15 are both inorganic materials, for example, the first insulating layer 14 is silicon oxide and the second insulating layer 15 is silicon nitride.

[0061] FIG. 5 is a schematic diagram of a cross-sectional structure of a first electrode and a pixel definition layer in a display substrate according to an embodiment of the present disclosure. FIG. 5 illustrates the structure of the first electrode and the pixel definition layer in the display substrate shown in FIG. 4. In an example embodiment, as shown in FIGS. 4 and 5, the display substrate according to an embodiment of the present disclosure further includes a pixel definition layer 21, at least part of the pixel definition layer 21 is disposed on a side of the first electrode 11 away from the substrate 101, and the pixel definition layer 21 is provided with a pixel opening that defines a sub-pixel, the pixel opening exposes at least part of the first electrode 11, and the light-emitting functional layer 12 covers the pixel opening and contacts the first electrode 11 exposed by the pixel opening. The pixel definition layer 21 has a sidewall as a side of the pixel opening, and the sidewall is provided with an undercut structure 22 that can block part of the film layer of the light-emitting functional layer 12 thereabove. For example, the charge generation layer in the light-emitting functional layer 21 is blocked at the undercut structure, thereby preventing charge crosstalk between adjacent sub-pixels and avoiding pixel color mixing.

[0062] In an exemplary embodiment, the pixel definition layer 21 includes a first definition layer 21-1, a second definition layer 21-2, and a third definition layer 21-3 stacked in sequence along the direction away from the substrate. At least part of the first definition layer 21-1 covers the edge region of the first electrode 11 away from the substrate side surface, and the side surface of the first electrode 11. The first definition layer 21-1 has a first side wall 51 close to the middle region of the pixel opening, the second definition layer 21-2 has a second side wall 52 close to the middle region of the pixel opening, and the third definition layer 21-3 has a third side wall 53 close to the middle region of the pixel opening. The first side wall 51 is connected to the first electrode 11 away from the substrate side surface, and the first side wall 51 respectively protrudes compared to the second side wall 52 and the third side wall 53. The second side wall 52 respectively recesses compared to the first side wall 51 and the third side wall 53. The third side wall 53 protrudes compared to the second side wall 52, forming an undercut structure 22.

[0063] In an exemplary embodiment, the first definition layer 21-1, the second definition layer 21-2, and the third definition layer 21-3 can all be inorganic materials, and the second definition layer 21-2 has an etching selectivity ratio with the first definition layer 21-1 and the third definition layer 21-3, so that the pixel definition layer 21 can form the undercut structure 22 through an etching process. For example, the first definition layer 21-1 and the third definition layer 21-3 can both be silicon oxide, and the second definition layer 21-2 can be silicon nitride.

[0064] In an exemplary embodiment, the thickness of the first definition layer 21-1 can be 50 angstroms to 500 angstroms, the thickness of the second definition layer 21-2 can be 300 angstroms to 1000 angstroms, and the thickness of the third definition layer 21-3 can be 50 angstroms to 500 angstroms.

[0065] In an exemplary embodiment, the first electrode 11 can be a full reflection electrode. The first electrode 11 can be a single film layer or a multi-film layer structure, prepared by a sputtering process.

[0066] In an exemplary embodiment, the first electrode 11 can be a weak microcavity structure. The first electrode 11 can include a first conductive pattern 11-1, a second conductive pattern 11-2, and a third conductive pattern 11-3 stacked in sequence along the direction away from the substrate, the first conductive pattern 11-1 being disposed on the side of the second insulating layer 15 away from the substrate 101; the second conductive pattern 11-2 being disposed on the side of the first conductive pattern 11-1 away from the substrate 101, and being in contact with the first conductive pattern 11-1; the third conductive pattern 11-3 being disposed on the side of the second conductive pattern 11-2 away from the substrate 101, and covering the side surface and the surface away from the substrate 101 of the second conductive pattern 11-2, the third conductive pattern 11-3 wrapping the side surface and the surface away from the substrate 101 of the second conductive pattern 11-2.

[0067] In an exemplary embodiment, the material of the first conductive pattern 11-1 and the third conductive pattern 11-3 can be a metal compound, for example, indium tin oxide (ITO), and the material of the second conductive pattern 11-2 can be a conductive metal, for example, silver, aluminum, etc. The thickness of the first conductive pattern 11-1 and the third conductive pattern 11-3 can each be 70 angstroms to 100 angstroms, and the thickness of the second conductive pattern 11-2 can be 800 angstroms to 1200 angstroms.

[0068] In some embodiments, the first electrode can include a number of conductive layers other than three, for example, the first electrode can include two, four, five, six, etc. number of conductive layers. For example, the first electrode can include four conductive layers, the first electrode can include a first conductive pattern, a second conductive pattern, a third conductive pattern, and a fourth conductive layer stacked in order along a direction perpendicular to the substrate, the material of the first conductive pattern can be titanium, the material of the second conductive pattern can be aluminum, the material of the third conductive pattern can be titanium or titanium nitride, and the material of the fourth conductive layer can be indium tin oxide, the thickness of the first conductive pattern can be 50 angstroms to 100 angstroms, the thickness of the second conductive pattern can be 800 angstroms to 2000 angstroms, the thickness of the third conductive pattern can be 50 angstroms to 100 angstroms, and the thickness of the fourth conductive layer can be 50 angstroms to 100 angstroms.

[0069] FIG. 6 is a schematic diagram of a cross-sectional structure of another first electrode and a pixel definition layer in a substrate according to an embodiment of the present disclosure. In an exemplary embodiment, as shown in FIG. 6, the first electrode 11 can be a strong microcavity structure. The first electrode 11 can include a first conductive pattern 11-1, a second conductive pattern 11-2, a dielectric layer 11-4, and a third conductive pattern 11-3 stacked in order along a direction perpendicular to the substrate, the second conductive pattern 11-2 is disposed on the side of the first conductive pattern 11-1 away from the substrate 101, the dielectric layer 11-4 is disposed on the side of the second conductive pattern 11-2 away from the substrate 101, and the third conductive pattern 11-3 is disposed on the side of the dielectric layer 11-4 away from the substrate 101. The dielectric layer 11-4 is provided with a via, and the third conductive pattern 11-3 is connected to the second conductive pattern 11-2 through the via. The dielectric layer 11-4 is used to adjust the vertical distance h between the surface on the side of the first electrode 11 away from the substrate and the surface of the substrate.

[0070] In an exemplary embodiment, the material of the dielectric layer 11-4 can include a conductive material, for example, the material of the dielectric layer 11-4 can include at least one of indium tin oxide (ITO) and indium zinc oxide (IZO). The material of the dielectric layer 11-4 can also include an inorganic substance, for example, the material of the dielectric layer 11-4 can include at least one of silicon oxide, silicon nitride, and silicon oxynitride.

[0071] In an exemplary embodiment, the medium layer 11-4 can be a light-transmitting material, and the light transmittance of the medium layer 11-4 to visible light is greater than 90%.

[0072] FIG. 7 is a schematic diagram of a structure of a light-emitting functional layer in a display substrate according to an embodiment of the present disclosure. FIG. 7 illustrates the structure of the light-emitting functional layer in the display substrate shown in FIG. 4. In an exemplary embodiment, as shown in FIG. 4 and FIG. 7, the light-emitting functional layer 12 is located between the first electrode 11 and the second electrode 13, and is in contact with the first electrode 11 and the second electrode 13, respectively. The light-emitting functional layer 12 can include a first light-emitting unit 12-1 and a second light-emitting unit 12-2 stacked in sequence along a direction away from the substrate 101, and a charge generation layer 30 disposed between the first light-emitting unit 12-1 and the second light-emitting unit 12-2. The charge generation layer 30 of adjacent sub-pixels is disconnected at an undercut structure of the pixel definition layer.

[0073] In an exemplary embodiment, the first light-emitting unit 12-1 is located on the side of the second light-emitting unit 12-2 close to the substrate, and is connected in series with the second light-emitting unit 12-2 through the charge generation layer 30.

[0074] The display substrate according to an embodiment of the present disclosure realizes the effect of emitting white light by superimposing the light emitted by the first light-emitting unit 12-1 and the light emitted by the second light-emitting unit 12-2.

[0075] In an exemplary embodiment, the sum of the thicknesses of the light-emitting functional layer 12 and the second electrode 13 is 200 nanometers to 250 nanometers. For example, the sum of the thicknesses of the light-emitting functional layer 12 and the second electrode 13 is 210 nanometers to 230 nanometers.

[0076] In an exemplary embodiment, the first light-emitting unit 12-1 can include a first auxiliary layer 41, a first light-emitting layer 31, and a second auxiliary layer 42 stacked in sequence along a direction away from the substrate 101, and the first light-emitting layer 31 is in contact with the first auxiliary layer 41 and the second auxiliary layer 42, respectively. The first auxiliary layer 41 is located on the side of the first light-emitting layer 31 close to the substrate, and is in contact with the first electrode; and the second auxiliary layer 42 is located on the side of the first light-emitting layer 31 away from the substrate, and is in contact with the charge generation layer 30.

[0077] In an exemplary embodiment, the first auxiliary layer 41 includes at least a first hole transport layer 41-1 (HTL), and the first hole transport layer 41-1 is disposed between the first light-emitting layer 31 and the first electrode 11. The first auxiliary layer 41 can further include a first hole injection layer 41-2 (HIL) and a first functional layer 41-3 (prime), the first hole injection layer 41-2 is located on the side of the first hole transport layer 41-1 close to the substrate, and is in contact with the first electrode 11; and the first functional layer 41-3 is located on the side of the first hole transport layer 41-1 away from the substrate, and is in contact with the first light-emitting layer 31.

[0078] In an exemplary embodiment, the second auxiliary layer 42 includes at least a first electron transport layer 42-1 (ETL), which is disposed between the first light emitting layer 31 and the second electrode 13. The second auxiliary layer 42 can further include a first hole blocking layer 42-2 (HBL), which is disposed on the first electron transport layer 42-1 side close to the substrate and in contact with the first light emitting layer 31.

[0079] In an exemplary embodiment, the first light emitting layer 31 can emit yellow light, and the second light emitting layer 32 can emit blue light. The first light emitting layer 31 can include a plurality of sub-light emitting layers. For example, the first light emitting layer 31 includes a first sub-light emitting layer and a second sub-light emitting layer disposed in sequence along the direction away from the substrate, one of the first sub-light emitting layer and the second sub-light emitting layer is a red light emitting layer and can emit red light, and the other of the first sub-light emitting layer and the second sub-light emitting layer is a green light emitting layer and can emit green light; or, one of the first sub-light emitting layer and the second sub-light emitting layer can be a yellow light emitting layer and emit yellow light, and the other of the first sub-light emitting layer and the second sub-light emitting layer can be a green light emitting layer and a red light emitting layer stacked along the direction perpendicular to the substrate and emit yellow light. Alternatively, the first light emitting layer 31 can be a yellow light emitting layer and emit yellow light.

[0080] In an exemplary embodiment, the first light emitting layer 31 can be a phosphorescent material.

[0081] In an exemplary embodiment, the second light emitting unit 12-2 can include a third auxiliary layer 43, a second light emitting layer 32, and a fourth auxiliary layer 44 stacked in sequence along the direction away from the substrate 101, and the second light emitting layer 32 is in contact with the third auxiliary layer 43 and the fourth auxiliary layer 44, respectively. The third auxiliary layer 43 is located on the second light emitting layer 32 side close to the substrate and in contact with the charge generation layer 30, and the fourth auxiliary layer 44 is located on the second light emitting layer 32 side away from the substrate and in contact with the second electrode 13.

[0082] In an exemplary embodiment, the third auxiliary layer 43 includes at least a second hole transport layer 43-1 (HTL), which is disposed between the second light emitting layer 32 and the first electrode 11 and in contact with the charge generation layer 30. The third auxiliary layer 43 can further include a second functional layer 43-2 (prime), which is located on the second hole transport layer 43-1 side away from the substrate and in contact with the second light emitting layer 32.

[0083] In an exemplary embodiment, the fourth auxiliary layer 44 includes at least a second electron transport layer 44-1 (ETL), which is disposed between the second light emitting layer 32 and the second electrode 13. The second auxiliary layer 42 can further include a second hole blocking layer 44-2 (HBL), which is disposed on the side of the second electron transport layer 44-1 close to the substrate and in contact with the second light emitting layer 32, and an electron injection layer 44-3 (EIL), which is disposed on the side of the second electron transport layer 44-1 away from the substrate and in contact with the second electrode 13.

[0084] In an exemplary embodiment, the second light emitting layer 32 can emit blue light, and the second light emitting layer 32 is a blue light emitting layer.

[0085] In an exemplary embodiment, the second light emitting layer 32 can be a fluorescent material or a phosphorescent material.

[0086] In some embodiments, the second light emitting layer can emit yellow light, and the first light emitting layer can emit blue light. The second light emitting layer can include a plurality of sub-light emitting layers. For example, the second light emitting layer includes a first sub-light emitting layer and a second sub-light emitting layer disposed in sequence along the direction away from the substrate, one of the first sub-light emitting layer and the second sub-light emitting layer can emit red light, and the other of the first sub-light emitting layer and the second sub-light emitting layer can emit green light; or, one of the first sub-light emitting layer and the second sub-light emitting layer can emit yellow light, and the other of the first sub-light emitting layer and the second sub-light emitting layer can be a green light emitting layer and a red light emitting layer stacked along the direction perpendicular to the substrate, emitting yellow light. Or, the second light emitting layer can be a yellow light emitting layer, emitting yellow light.

[0087] In an exemplary embodiment, the charge generation layer 30 can include a first generation layer 30-1 and a second generation layer 30-2 disposed in sequence along the direction away from the substrate, and the first generation layer 30-1 and the second generation layer 30-2 are in contact with each other. The first generation layer 30-1 is located on the side of the second generation layer 30-2 close to the substrate and in contact with the first electron transport layer 42-1. The first generation layer 30-1 can be an N-type charge generation layer. The second generation layer 30-2 is located on the side of the first generation layer 30-1 away from the substrate and in contact with the second hole transport layer 43-1. The second generation layer 30-2 can be a P-type charge generation layer.

[0088] In some embodiments, the light emitting functional layer can include a first light emitting unit, a second light emitting unit and a third light emitting unit stacked in sequence along the direction away from the substrate, a first charge generation layer disposed between the first light emitting unit and the second light emitting unit, and a second charge generation layer disposed between the second light emitting unit and the third light emitting unit, and the light emitted by the first light emitting unit, the second light emitting unit and the third light emitting unit is superimposed to achieve the effect of emitting white light.

[0089] In an exemplary embodiment, the second electrode 13 can transmit visible light, for example, the transmittance of the second electrode 13 to visible light is greater than or equal to 80%. Alternatively, the second electrode 13 can transmit a certain amount of visible light and reflect a certain amount of visible light, for example, the transmittance of the second electrode 13 to visible light is 50%, and the reflectance of the second electrode 13 to visible light is 50%.

[0090] In an exemplary embodiment, the light-emitting functional layer 12 covers the undercut structure 22 of the pixel definition layer 21, at least part of the film layer of the light-emitting functional layer 12 forms a recessed area 23 at the undercut structure 22 of the pixel definition layer 21, and the recessed area 23 is recessed along the direction close to the substrate. One end of the recessed area 23 is connected with a first protrusion 24, and the first protrusion 24 protrudes along the direction away from the substrate; the other end of the recessed area 23 is connected with a second protrusion 25, and the second protrusion 25 protrudes along the direction away from the substrate. For example, the second light-emitting layer 32, the third auxiliary layer 43, the charge generation layer 30, the second auxiliary layer 42 and the first light-emitting layer 31 in the light-emitting functional layer 12 all form a recessed area 23 at the undercut structure 22 of the pixel definition layer 21. The recessed area 23 makes the topography of the light-emitting functional layer 12 irregular, causes carrier accumulation and abnormal transport, leads to the occurrence of carrier abnormal transport leakage, and causes the carrier accumulation to cause the adverse "edge effect" of life decay.

[0091] In an exemplary embodiment, the hole mobility of the first hole transport layer 41-1 in the first light-emitting unit 12-1 is greater than or equal to 7*10 -6 cm 2 / Vs and less than or equal to 5*10 -4 cm 2 / Vs. For example, the hole mobility of the first hole transport layer 41-1 is greater than or equal to 1*10 -5 cm 2 / Vs and less than or equal to 1*10 -4 cm 2 / Vs. The electron mobility of the first electron transport layer 42-1 in the first light-emitting unit 12-1 is greater than or equal to 1*10 -6 cm 2 / Vs and less than or equal to 1*10 -4 cm 2 / Vs. For example, the electron mobility of the first electron transport layer 42-1 in the first light-emitting unit 12-1 is greater than or equal to 1*10 -5 cm 2 / Vs and less than or equal to 8*10 -5 cm 2 / Vs.

[0092] This embodiment of the display shows that the substrate controls the hole mobility of the first hole transport layer 41-1 in the first light-emitting unit 12-1 to be greater than or equal to 7*10. -6 cm 2 / Vs is less than or equal to 5*10 -4 cm 2 / Vs, reducing the hole mobility of the first hole transport layer 41-1, increasing the resistance of the first hole transport layer 41-1 in the recessed region 23, and improving the leakage current caused by abnormal carrier transport in the recessed region 23.

[0093] This embodiment of the display substrate controls the electron mobility of the first electron transport layer 42-1 to be greater than or equal to 1*10. -6 cm 2 / Vs is less than or equal to 1*10 -4 cm 2 / Vs increases the electron mobility of the first electron transport layer 42-1, accelerates the electron transport speed of the first electron transport layer 42-1, prevents electrons from accumulating in the recessed area 23, and improves the service life of the display substrate.

[0094] In an exemplary embodiment, the hole mobility of the second hole transport layer 43-1 in the second light-emitting unit 12-2 is greater than or equal to 7*10. -6 cm 2 / Vs is less than or equal to 5*10 -4 cm 2 / Vs. For example, the hole mobility of the second hole transport layer 43-1 is greater than or equal to 1*10. -5 cm 2 / Vs is less than or equal to 1*10 -4 cm 2 / Vs. The electron mobility of the second electron transport layer 44-1 in the second light-emitting unit 12-2 is greater than or equal to 1*10. -6 cm 2 / Vs is less than or equal to 1*10 -4 cm 2 / Vs. For example, the electron mobility of the second electron transport layer 44-1 in the second light-emitting unit 12-2 is greater than or equal to 1*10. -5 cm 2 / Vs is less than or equal to 8*10 -5 cm 2 / Vs.

[0095] This embodiment of the display shows that the substrate controls the hole mobility of the second hole transport layer 43-1 in the second light-emitting unit 12-2 to be greater than or equal to 7*10. -6 cm 2 / Vs is less than or equal to 5*10 -4 cm2 / Vs, reducing the hole mobility of the second hole transport layer 43-1, increasing the resistance of the second hole transport layer 43-1 in the recessed region 23, and improving the leakage current caused by abnormal carrier transport in the recessed region 23.

[0096] This embodiment of the display shows that the substrate controls the electron mobility of the second electron transport layer 44-1 to be greater than or equal to 1*10. -6 cm 2 / Vs is less than or equal to 1*10 -4 cm 2 / Vs increases the electron mobility of the second electron transport layer 44-1, accelerates the electron transport speed of the second electron transport layer 44-1, prevents electrons from accumulating in the recessed area 23, and improves the service life of the display substrate.

[0097] Simulation experiments were conducted on the display substrate. The hole mobility of the hole transport layer in the light-emitting functional layer of the display substrate was 9.0 cm⁻¹. 2 / Vs*10 -4 cm 2 / Vs, the electron mobility of the electron transport layer is 5.2 cm. 2 / Vs*10 -4 cm 2 At a value of / Vs, both the hole mobility and electron mobility of the light-emitting functional layer are relatively high, resulting in a device efficiency of 87%, a maximum brightness of 100%, and a lifespan of 100% for the display substrate. When the hole mobility of the hole transport layer in the light-emitting functional layer of the display substrate is 1.2cm... 2 / Vs*10 -7 cm 2 / Vs, the electron mobility of the electron transport layer is 5.3 cm. 2 / Vs*10 -7 cm 2 At a value of / Vs, both the hole mobility and electron mobility of the light-emitting functional layer are relatively low, resulting in a device efficiency of 100%, a maximum brightness of 60%, and a lifespan of 73% for the display substrate. When the hole mobility of the hole transport layer in the light-emitting functional layer of the display substrate is 5.3cm... 2 / Vs*10 -5 cm 2 / Vs, the electron mobility of the electron transport layer is 3.5 cm. 2 / Vs*10 -5 cm 2 At / Vs, the hole mobility and electron mobility of the light-emitting functional layer match the morphology of the light-emitting functional layer, the device efficiency of the display substrate is 97%, the maximum brightness is 100%, and the lifespan of the display substrate is 97%.

[0098] As can be seen from the simulation results above, the hole mobility of the hole transport layer in the light-emitting functional layer 12 of the display substrate is greater than or equal to 7*10^6. -6 cm 2 / Vs is less than or equal to 5*10 -4 cm 2 / Vs, and the electron mobility of the control electron transport layer is greater than or equal to 1*10 -6 cm 2 / Vs is less than or equal to 1*10 -4 cm 2 / Vs, so that the mobility of holes and electrons in the light-emitting functional layer 12 matches the morphology (e.g., the recessed region) of the light-emitting functional layer 12, thereby solving the problems of leakage and reduced lifetime of the light-emitting functional layer 12.

[0099] This disclosure also provides a method for preparing a display substrate, including:

[0100] Step 101: A first conductive film is formed on the substrate by sputtering; then, the first conductive film is patterned by processes such as coating / exposure / development / etching / stripping to form the first electrode corresponding to different sub-pixels.

[0101] Step 102: A pixel definition layer is formed on the side of the first electrode away from the substrate. Pixel openings are provided in the pixel definition layer, and the pixel openings expose the first electrode of each sub-pixel.

[0102] Step 103: A light-emitting functional layer is formed on the side of the pixel definition layer away from the substrate using a vapor deposition process. This light-emitting functional layer covers the pixel opening and contacts the exposed first electrode. Some layers in the light-emitting functional layers of all sub-pixels can be common layers connected together. The hole mobility of the hole transport layer of the light-emitting functional layer is greater than or equal to 7*10⁻⁶. -6 cm 2 / Vs is less than or equal to 5*10 -4 cm 2 / Vs, the electron mobility of the electron transport layer in the light-emitting functional layer is greater than or equal to 1*10 -6 cm 2 / Vs is less than or equal to 1*10 -4 cm 2 / Vs.

[0103] Step 104: A second electrode is formed on the side of the light-emitting functional layer away from the substrate. The second electrodes of all sub-pixels can be a common layer connected together.

[0104] Step 105: Using thin film encapsulation (TFE), an encapsulation layer is formed on the side of the second electrode away from the substrate.

[0105] Step 106, forming a color filter structure layer away from the base side of the encapsulation layer, the color filter structure layer comprising a black matrix (BM) and a color filter (CF), the color filter can correspond to the pixel opening of the pixel definition layer.

[0106] The display device can be any product or component with display function, such as a mobile phone, a wearable device, an AR or VR display device, a vehicle-mounted display device, a tablet computer, a television, a display, a notebook computer, a digital photo frame, a navigator, etc., and the embodiments of the present application are not limited thereto.

[0107] The present application also provides a preparation method of a display substrate, comprising:

[0108] forming a first electrode, a light-emitting functional layer and a second electrode in sequence along the direction away from the base;

[0109] The light-emitting functional layer comprises at least one light-emitting unit, the at least one light-emitting unit comprises a light-emitting layer, a hole transport layer and an electron transport layer, the hole transport layer is located between the light-emitting layer and the first electrode, the hole mobility of the hole transport layer is greater than or equal to 7*10 -6 cm 2 / Vs, the electron transport layer is located between the light-emitting layer and the second electrode, the electron mobility of the electron transport layer is greater than or equal to 1*10 -4 cm 2 / Vs, the electron transport layer is located between the light-emitting layer and the second electrode, the electron mobility of the electron transport layer is greater than or equal to 1*10 -6 cm 2 / Vs, the electron transport layer is located between the light-emitting layer and the second electrode, the electron mobility of the electron transport layer is greater than or equal to 1*10 -4 cm 2 / Vs.

[0110] Although the embodiments of the present application are disclosed as above, the content described is only the embodiments adopted for the purpose of understanding the present application, and is not intended to limit the present application. Any person skilled in the art can make any modification and change in the form and details without departing from the spirit and scope of the present application, and the patent protection scope of the present application shall be subject to the scope defined by the appended claims.

Claims

1. A display substrate comprising at least one sub-pixel, the at least one sub-pixel comprising a first electrode, a light-emitting functional layer, and a second electrode which are sequentially stacked in a direction away from a substrate; the light-emitting functional layer comprising at least one light-emitting unit, the at least one light-emitting unit comprising a light-emitting layer, a hole transport layer, and an electron transport layer, the hole transport layer being located between the light-emitting layer and the first electrode, the hole transport layer having a hole mobility greater than or equal to 7*10 6 cm 2 / Vs and less than or equal to 5*10 6 cm 2 / Vs, the electron transport layer being located between the light-emitting layer and the second electrode, the electron transport layer having an electron mobility greater than or equal to 1*10 6 cm 2 / Vs and less than or equal to 1*10 6 cm 2 / Vs. -6 cm 2 / Vs -4 cm 2 / Vs -6 cm 2 / Vs -4 cm 2 / Vs 2.The display substrate of claim 1, wherein, The hole transport layer has a hole mobility greater than or equal to 1*10 -5 cm 2 / Vs less than or equal to 1*10 -4 cm 2 / Vs. 3.The display substrate of claim 1, wherein, The electron mobility of the electron transport layer is greater than or equal to 1*10 -5 cm 2 The / Vs is less than or equal to 8*10 -5 cm 2 / Vs. 4.The display substrate of any one of claims 1-3, wherein, The light-emitting functional layer includes a first light-emitting unit and a second light-emitting unit stacked in sequence in a direction away from the substrate, and a charge generation layer disposed between the first light-emitting unit and the second light-emitting unit, the first light-emitting unit includes a first light-emitting layer, a first hole transport layer, and a first electron transport layer, the first hole transport layer is disposed between the first light-emitting layer and the first electrode, the hole mobility of the first hole transport layer is greater than or equal to 7*10 -6 cm 2 / Vs is less than or equal to 5*10 -4 cm 2 / Vs, the first electron transport layer is disposed between the first light-emitting layer and the second electrode, the electron mobility of the first electron transport layer is greater than or equal to 1*10 -6 cm 2 / Vs is less than or equal to 1*10 -4 cm 2 / Vs; the second light-emitting unit includes a second light-emitting layer, a second hole transport layer, and a second electron transport layer, the second hole transport layer is disposed between the second light-emitting layer and the first electrode, the hole mobility of the second hole transport layer is greater than or equal to 7*10 -6 cm 2 / Vs is less than or equal to 5*10 -4 cm 2 / Vs, the second electron transport layer is disposed between the second light-emitting layer and the second electrode, the electron mobility of the second electron transport layer is greater than or equal to 1*10 -6 cm 2 / Vs is less than or equal to 1*10 -4 cm 2 / Vs. 5.The display substrate of claim 4, wherein, One of the first light-emitting layer and the second light-emitting layer emits yellow light, and the other of the first light-emitting layer and the second light-emitting layer emits blue light. 6.The display substrate of claim 4, wherein, One of the first light-emitting layer and the second light-emitting layer is a yellow light-emitting layer, and the other of the first light-emitting layer and the second light-emitting layer is a blue light-emitting layer; or one of the first light-emitting layer and the second light-emitting layer comprises a first sub-light-emitting layer and a second sub-light-emitting layer arranged in sequence along a direction away from the substrate, one of the first sub-light-emitting layer and the second sub-light-emitting layer is a red light-emitting layer, and the other of the first sub-light-emitting layer and the second sub-light-emitting layer is a green light-emitting layer, and the other of the first light-emitting layer and the second light-emitting layer is a blue light-emitting layer; or one of the first light-emitting layer and the second light-emitting layer comprises a first sub-light-emitting layer and a second sub-light-emitting layer arranged in sequence along a direction away from the substrate, one of the first sub-light-emitting layer and the second sub-light-emitting layer is a yellow light-emitting layer, and the other of the first sub-light-emitting layer and the second sub-light-emitting layer is a green light-emitting layer and a red light-emitting layer stacked with each other, and the other of the first light-emitting layer and the second light-emitting layer is a blue light-emitting layer. 7.The display substrate of claim 4, wherein, The light-emitting functional layer further comprises a first hole injection layer, a first functional layer, a first hole blocking layer, a second functional layer, a second hole blocking layer and an electron injection layer, the first hole injection layer is located on a side of the first hole transport layer close to the substrate and in contact with the first electrode; the first functional layer is located on a side of the first hole transport layer away from the substrate and in contact with the first light-emitting layer; the first hole blocking layer is arranged on a side of the first electron transport layer close to the substrate and in contact with the first light-emitting layer; the second functional layer is located on a side of the second hole transport layer away from the substrate and in contact with the second light-emitting layer; the second hole blocking layer is arranged on a side of the second electron transport layer close to the substrate and in contact with the second light-emitting layer; and the electron injection layer is arranged on a side of the second electron transport layer away from the substrate and in contact with the second electrode.

8. The display substrate according to any one of claims 1 to 3, wherein The sum of the thicknesses of the light-emitting functional layer and the second electrode is 200 nanometers to 250 nanometers.

9. The display substrate of any one of claims 1 to 3, further comprising a pixel definition layer arranged on a side of the first electrode away from the substrate, the pixel definition layer being provided with a pixel opening exposing at least part of the first electrode, the pixel definition layer being provided with an undercut structure, at least part of the light-emitting functional layer covering the undercut structure, and at least part of the light-emitting functional layer forming a recessed region at the undercut structure. 10.The display substrate of claim 9, wherein, The pixel definition layer comprises a first definition layer, a second definition layer and a third definition layer stacked in sequence along the direction away from the substrate, at least part of the first definition layer covers the edge area of the side surface of the first electrode away from the substrate, and the side surface of the first electrode, the first definition layer has a first side wall close to the middle area of the pixel opening, the second definition layer has a second side wall close to the middle area of the pixel opening, and the third definition layer has a third side wall close to the middle area of the pixel opening, the first side wall is connected with the side surface of the first electrode away from the substrate, the first side wall respectively protrudes compared with the second side wall and the third side wall, the third side wall protrudes compared with the second side wall, and the undercut structure is formed. 11.The display substrate of claim 10, wherein, The thickness of the first definition layer is 50 angstroms to 500 angstroms, the thickness of the second definition layer is 300 angstroms to 1000 angstroms, and the thickness of the third definition layer is 50 angstroms to 500 angstroms.

12. The display substrate according to any one of claims 1 to 3, wherein The first electrode comprises a first conductive pattern, a second conductive pattern and a third conductive pattern stacked in sequence along the direction away from the substrate, the thickness of the first conductive pattern and the third conductive pattern is 70 angstroms to 100 angstroms, and the thickness of the second conductive pattern is 800 angstroms to 1200 angstroms.

13. The display substrate according to any one of claims 1 to 3, wherein The first electrode comprises a first conductive pattern, a second conductive pattern, an insulating medium layer and a third conductive pattern stacked in sequence along the direction away from the substrate, the insulating medium layer is provided with a via hole, and the third conductive pattern is connected with the second conductive pattern through the via hole.

14. A preparation method of a display substrate, comprising: forming a first electrode, a light-emitting functional layer and a second electrode in sequence along the direction away from the substrate; Among them, the light-emitting functional layer includes at least one light-emitting unit, and the at least one light-emitting unit includes a light-emitting layer, a hole transport layer, and an electron transport layer. The hole transport layer is located between the light-emitting layer and the first electrode, and the hole mobility of the hole transport layer is greater than or equal to 7×10 -6 cm 2 / Vs and less than or equal to 5×10 -4 cm 2 / Vs. The electron transport layer is located between the light-emitting layer and the second electrode, and the electron mobility of the electron transport layer is greater than or equal to 1×10 -6 cm 2 / Vs and less than or equal to 1×10 -4 cm 2 / Vs.

15. A display device comprising the display substrate according to any one of claims 1 to 13.

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