Display panel

Abstract

Disclosed in the embodiments of the present application is a display panel. A hole control layer is provided on a hole transport layer; and a light-emitting material layer is provided on the hole control layer. The hole control layer comprises a first hole control sub-layer and a second hole control sub-layer, wherein the energy level difference between the HOMO energy levels of the first hole control sub-layer and the second hole control sub-layer is greater than or equal to 0.2eV, and the HOMO energy level of the second hole control sub-layer is greater than the HOMO energy level of the light-emitting material layer and smaller than the HOMO energy level of the hole transfer layer.

Description

Display panel Technical Field

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

[0002] Organic light-emitting diode (OLED) displays are already widely used in our daily lives, such as in mobile phones, computers, and car displays. OLED panels consist of multiple light-emitting devices that emit light to display images. The independent self-luminescence of the red, green, and blue light-emitting devices within an OLED panel allows for high-contrast color images.

[0003] However, if there is a significant difference in the turn-on voltage (Vth) of red, green, and blue light-emitting devices, it will cause a light-emitting device of a certain color to light up or leak light under a black screen. For example, if the turn-on voltage of the green light-emitting device is higher than that of the red light-emitting device, when only the green light-emitting device is to be lit, the red light-emitting device will also be lit. SUMMARY OF THE INVENTION

[0004] The embodiments of the present application provide a display panel that can solve the problem of a light-emitting device of a certain color shining brightly or leaking light under a black screen.

[0005] An embodiment of the present application provides a display panel, comprising:

[0006] a first electrode;

[0007] a hole transport layer, disposed on the first electrode;

[0008] a hole control layer, disposed on the hole transport layer;

[0009] a light-emitting material layer, disposed on the hole control layer;

[0010] a second electrode disposed on the light-emitting material layer;

[0011] The hole control layer includes a first sub-hole control layer and a second sub-hole control layer, the thickness of the first sub-hole control layer is less than the thickness of the second sub-hole control layer, and the energy level difference between the HOMO energy levels of the first sub-hole control layer and the second sub-hole control layer is greater than or equal to 0.2 eV.

[0012] The HOMO energy level of the second sub-hole control layer is greater than the HOMO energy level of the light-emitting material layer, and is less than the HOMO energy level of the hole transport layer.

[0013] Optionally, in some embodiments, the hole mobility of the first hole control sub-layer is smaller than the hole mobility of the second hole control sub-layer.

[0014] Optionally, in some embodiments, a ratio of the hole mobility of the first hole control sub-layer to the hole mobility of the second hole control sub-layer is less than or equal to 0.8.

[0015] Optionally, in some embodiments, the first sub-hole control layer is disposed between the hole transport layer and the second sub-hole control layer.

[0016] Optionally, in some embodiments, the HOMO energy level of the first sub-hole control layer is greater than the HOMO energy level of the light-emitting material layer, and less than the HOMO energy level of the second sub-hole control layer.

[0017] The LUMO energy level of the first hole control sub-layer is greater than the LUMO energy level of the light-emitting material layer, and is less than the LUMO energy levels of the second hole control sub-layer and the hole transport layer.

[0018] Optionally, in some embodiments, the HOMO energy level of the first sub-hole control layer is greater than the HOMO energy level of the hole transport layer;

[0019] The LUMO energy level of the first hole control sub-layer is greater than the LUMO energy levels of the light-emitting material layer, the second hole control sub-layer, and the hole transport layer.

[0020] Optionally, in some embodiments, the first sub-hole control layer is disposed between the second sub-hole control layer and the light-emitting material layer.

[0021] Optionally, in some embodiments, the HOMO energy level of the first sub-hole control layer is greater than the HOMO energy level of the second sub-hole control layer, and is less than the HOMO energy level of the hole transport layer;

[0022] The LUMO energy level of the first sub-hole control layer is greater than the LUMO energy level of the light-emitting material layer, and is less than the LUMO energy level of the hole transport layer.

[0023] Optionally, in some embodiments, the HOMO energy level of the first sub-hole control layer is lower than the HOMO energy level of the light-emitting material layer;

[0024] The LUMO energy level of the first sub-hole control layer is greater than the LUMO energy level of the light-emitting material layer, and is less than the LUMO energy level of the hole transport layer.

[0025] Optionally, in some embodiments, the LUMO energy level of the first sub-hole control layer is equal to the LUMO energy level of the second sub-hole control layer.

[0026] Optionally, in some embodiments, the thickness of the first sub-hole control layer is in a range of 3 nanometers to 10 nanometers.

[0027] Optionally, in some embodiments, the LUMO energy level of the second sub-hole control layer is greater than the LUMO energy level of the light-emitting material layer, and less than the LUMO energy level of the hole transport layer;

[0028] An energy level difference between the LUMO energy level of the second hole control sub-layer and the LUMO energy level of the light-emitting material layer is greater than or equal to 0.2 eV. Beneficial effects

[0029] In the present application, a display panel is provided, comprising: a first electrode; a hole transport layer, arranged on the first electrode; a hole control layer, arranged on the hole transport layer; a luminescent material layer, arranged on the hole control layer; and a second electrode, arranged on the luminescent material layer; wherein the hole control layer comprises a first sub-hole control layer and a second sub-hole control layer, the thickness of the first sub-hole control layer is less than the thickness of the second sub-hole control layer, the energy level difference between the HOMO energy levels of the first sub-hole control layer and the second sub-hole control layer is greater than or equal to 0.2 eV, and the HOMO energy level of the second sub-hole control layer is greater than the HOMO energy level of the luminescent material layer and less than the HOMO energy level of the hole transport layer. In the present application, a hole control layer is added to the light-emitting device or display panel, and the hole control layer includes a first sub-hole control layer and a second sub-hole control layer. The energy level difference between the HOMO energy levels of the first sub-hole control layer and the second sub-hole control layer is greater than or equal to 0.2 eV, and the HOMO energy level of the second sub-hole control layer is greater than the HOMO energy level of the light-emitting material layer and less than the HOMO energy level of the hole transport layer, so that a potential barrier difference is formed between the second sub-hole control layer and the hole transport layer, or between the second sub-hole control layer and the light-emitting material layer, forming a deep HOMO energy level trap, increasing the hole injection barrier, and thus improving the turn-on voltage of the light-emitting device. Therefore, even if there is a small amount of leakage current or leakage voltage between adjacent light-emitting devices, the light-emitting device originally in the dark state will not emit light, thereby solving the problem of a light-emitting device of a certain color secretly lighting up or leaking light under a completely black screen. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0031] FIG1 is a schematic cross-sectional view of a first light-emitting device provided in an embodiment of the present application;

[0032] FIG2 is a schematic diagram of the HOMO energy level of a light-emitting device provided in Example 1 of the present application;

[0033] FIG3 is a schematic diagram of the HOMO energy levels of a light-emitting device provided in Example 2 of the present application;

[0034] FIG4 is a schematic cross-sectional view of a second light-emitting device provided in an embodiment of the present application;

[0035] FIG5 is a schematic diagram of the HOMO energy levels of the light-emitting device provided in Example 3 of the present application;

[0036] FIG6 is a schematic diagram of the HOMO energy levels of the light-emitting device provided in Example 4 of the present application;

[0037] FIG7 is a schematic diagram of a measured operating voltage curve of the improved light-emitting device or display panel provided in an embodiment of the present application. Modes for Carrying Out the Invention

[0038] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present application. In addition, it should be understood that the specific implementation methods described herein are only used to illustrate and explain the present application, and are not used to limit the present application. In the present application, unless otherwise specified, the directional words used, such as "upper" and "lower", generally refer to the upper and lower parts of the device in actual use or working state, specifically the drawing direction in the accompanying drawings; and "inside" and "outside" refer to the outline of the device.

[0039] An embodiment of the present application provides a display panel, comprising: a first electrode; a hole transport layer, disposed on the first electrode; a hole control layer, disposed on the hole transport layer; a luminescent material layer, disposed on the hole control layer; and a second electrode, disposed on the luminescent material layer; wherein the hole control layer comprises a first sub-hole control layer and a second sub-hole control layer, the thickness of the first sub-hole control layer is less than the thickness of the second sub-hole control layer, the energy level difference between the HOMO energy levels of the first sub-hole control layer and the second sub-hole control layer is greater than or equal to 0.2 eV, the HOMO energy level of the second sub-hole control layer is greater than the HOMO energy level of the luminescent material layer, and less than the HOMO energy level of the hole transport layer.

[0040] Please refer to Figures 1 to 6. Figure 1 is a cross-sectional schematic diagram of the first light-emitting device provided in an embodiment of the present application; Figure 2 is a HOMO energy level schematic diagram of a light-emitting device provided in Example 1 of the present application; Figure 3 is a HOMO energy level schematic diagram of a light-emitting device provided in Example 2 of the present application; Figure 4 is a cross-sectional schematic diagram of the second light-emitting device provided in an embodiment of the present application; Figure 5 is a HOMO energy level schematic diagram of the light-emitting device provided in Example 3 of the present application; and Figure 6 is a HOMO energy level schematic diagram of the light-emitting device provided in Example 4 of the present application. Figures 2 and 3 are HOMO energy level schematic diagrams of the light-emitting device in Figure 1, and Figures 5 and 6 are HOMO energy level schematic diagrams of the light-emitting device in Figure 4.

[0041] The present application provides a display panel 100, which includes a first electrode 110, a hole transport layer 120, a hole control layer 130, a light-emitting material layer 140, and a second electrode 170; the hole transport layer 120 is disposed on the first electrode 110; the hole control layer 130 is disposed on the hole transport layer 120; the light-emitting material layer 140 is disposed on the hole control layer 130; the second electrode 170 is disposed on the light-emitting material layer 140; wherein the hole control layer 1 30 includes a first sub-hole control layer 131 and a second sub-hole control layer 132, the thickness of the first sub-hole control layer 131 is less than the thickness of the second sub-hole control layer 132, the energy level difference between the HOMO energy levels of the first sub-hole control layer 131 and the second sub-hole control layer 132 is greater than or equal to 0.2 eV, the HOMO energy level of the second sub-hole control layer 132 is greater than the HOMO energy level of the light-emitting material layer 140, and less than the HOMO energy level of the hole transport layer 120.

[0042] Specifically, the display panel 100 includes a light-emitting device, and the light-emitting device includes a first electrode 110 , a hole transport layer 120 , a hole control layer 130 , a light-emitting material layer 140 , and a second electrode 170 .

[0043] Specifically, the display panel 100 includes a substrate 11 , and a light emitting device or a first electrode 110 may be disposed on the substrate 11 .

[0044] Specifically, the first electrode 110 may be an anode, and the second electrode 170 may be a cathode; the first electrode 110 may also be a cathode, and the second electrode 170 may also be an anode. The following embodiments are described by taking the first electrode 110 as an anode.

[0045] Specifically, the energy level difference between the HOMO energy levels of the first sub-hole control layer 131 and the second sub-hole control layer 132 is greater than or equal to 0.2 eV, which means that the absolute value of the energy level difference between the HOMO energy levels of the first sub-hole control layer 131 and the second sub-hole control layer 132 is greater than or equal to 0.2 eV.

[0046] Specifically, a potential barrier difference is formed between the hole transport layer 120 and the first sub-hole control layer 131 in Figures 2, 5 and 6, a potential barrier difference is formed between the first sub-hole control layer 131 and the second sub-hole control layer 132 in Figures 3 and 6, and a potential barrier difference is formed between the second sub-hole control layer 132 and the light-emitting material layer 140 in Figures 2, 3 and 5, forming a deep HOMO energy level trap, increasing the hole injection barrier, and requiring a larger voltage for hole transport or positive carrier transport to occur, thereby increasing the turn-on voltage of the light-emitting device or display panel. Therefore, even if there is a small amount of leakage current or leakage voltage between adjacent light-emitting devices, the leakage voltage is less than the turn-on voltage of the light-emitting device, and the light-emitting device originally in the dark state will not emit light, thereby solving the problem of a certain color light-emitting device secretly lighting up or leaking light under a black screen.

[0047] In some embodiments, the hole mobility of the first hole control sub-layer 131 is less than the hole mobility of the second hole control sub-layer 132 .

[0048] Specifically, the thickness of the first sub-hole control layer 131 is smaller than the thickness of the second sub-hole control layer 132, and the hole mobility of the first sub-hole control layer 131 is smaller than the hole mobility of the second sub-hole control layer 132. Compared with the first sub-hole control layer 131, the thickness of the second sub-hole control layer 132 is thicker, maintaining the high thickness and high mobility of the second sub-hole control layer 132, so that the hole control layer 130 has high mobility, thereby keeping the operating voltage of the light-emitting device from increasing.

[0049] In some embodiments, a ratio of the hole mobility of the first hole control sub-layer 131 to the hole mobility of the second hole control sub-layer 132 is less than or equal to 0.8.

[0050] Specifically, the ratio of the hole mobility of the first sub-hole control layer 131 to the hole mobility of the second sub-hole control layer 132 is less than or equal to 0.8, maintaining the high thickness and high mobility of the second sub-hole control layer 132, so that the hole control layer 130 has high mobility, thereby keeping the operating voltage of the light-emitting device from increasing.

[0051] The following is a detailed description of the various embodiments. It should be noted that the order in which the embodiments are described below is not intended to limit the preferred order of the embodiments.

[0052] Example 1

[0053] In some embodiments, as shown in FIG. 1 , the first sub-hole control layer 131 is disposed between the hole transport layer 120 and the second sub-hole control layer 132 .

[0054] In some embodiments, the HOMO energy level of the first sub-hole control layer 131 is greater than the HOMO energy level of the light-emitting material layer 140, and less than the HOMO energy level of the second sub-hole control layer 132; the LUMO energy level of the first sub-hole control layer 131 is greater than the LUMO energy level of the light-emitting material layer 140, and less than the LUMO energy level of the second sub-hole control layer 132 and the hole transport layer 120.

[0055] Specifically, as shown in Figure 2, the HOMO energy level of the first sub-hole control layer 131 is greater than the HOMO energy level of the light-emitting material layer 140, and less than the HOMO energy level of the second sub-hole control layer 132. A potential barrier difference is formed between the hole transport layer 120 and the first sub-hole control layer 131, and a potential barrier difference is formed between the second sub-hole control layer 132 and the light-emitting material layer 140, forming two deep HOMO energy level traps, which increases the hole injection barrier. A larger voltage is required for hole transport or positive carrier transport to occur, thereby increasing the turn-on voltage of the light-emitting device or display panel.

[0056] Specifically, the LUMO energy level of the first sub-hole control layer 131 is greater than the LUMO energy level of the light-emitting material layer 140, and less than the LUMO energy level of the second sub-hole control layer 132 and the hole transport layer 120, which can block electrons from jumping from the light-emitting material layer 140 to the hole transport layer 120, thereby preventing the luminous efficiency from decreasing.

[0057] Example 2

[0058] In some embodiments, as shown in FIG. 1 , the first sub-hole control layer 131 is disposed between the hole transport layer 120 and the second sub-hole control layer 132 .

[0059] In some embodiments, the HOMO energy level of the first sub-hole control layer 131 is greater than the HOMO energy level of the hole transport layer 120; the LUMO energy level of the first sub-hole control layer 131 is greater than the LUMO energy level of the light-emitting material layer 140, the second sub-hole control layer 132, and the hole transport layer 120.

[0060] Specifically, as shown in Figure 3, the HOMO energy level of the first sub-hole control layer 131 is greater than the HOMO energy level of the hole transport layer 120, and a potential barrier difference is formed between the first sub-hole control layer 131 and the second sub-hole control layer 132, and a potential barrier difference is formed between the second sub-hole control layer 132 and the light-emitting material layer 140, forming two deep HOMO energy level traps, increasing the hole injection barrier, and requiring a larger voltage for hole transport or positive carrier transport to occur, thereby increasing the turn-on voltage of the light-emitting device or display panel.

[0061] Specifically, the LUMO energy level of the first sub-hole control layer 131 is greater than the LUMO energy levels of the luminescent material layer 140, the second sub-hole control layer 132, and the hole transport layer 120, which can block electrons from jumping from the luminescent material layer 140 to the hole transport layer 120, thereby preventing the luminescence efficiency from decreasing.

[0062] Example 3

[0063] In some embodiments, as shown in FIG. 4 , the first sub-hole control layer 131 is disposed between the second sub-hole control layer 132 and the light emitting material layer 140 .

[0064] In some embodiments, the HOMO energy level of the first sub-hole control layer 131 is greater than the HOMO energy level of the second sub-hole control layer 132, and less than the HOMO energy level of the hole transport layer 120; the LUMO energy level of the first sub-hole control layer 131 is greater than the LUMO energy level of the light-emitting material layer 140, and less than the LUMO energy level of the hole transport layer 120.

[0065] Specifically, as shown in Figure 5, the HOMO energy level of the first sub-hole control layer 131 is greater than the HOMO energy level of the second sub-hole control layer 132, and is less than the HOMO energy level of the hole transport layer 120. A potential barrier difference is formed between the hole transport layer 120 and the second sub-hole control layer 132, and a potential barrier difference is formed between the first sub-hole control layer 131 and the light-emitting material layer 140, forming two deep HOMO energy level traps, which increases the hole injection barrier. A larger voltage is required for hole transport or positive carrier transport to occur, thereby increasing the turn-on voltage of the light-emitting device or display panel.

[0066] Specifically, the LUMO energy level of the first sub-hole control layer 131 is greater than the LUMO energy level of the light-emitting material layer 140 and less than the LUMO energy level of the hole transport layer 120, which can block electrons from jumping from the light-emitting material layer 140 to the hole transport layer 120, thereby preventing the luminous efficiency from decreasing.

[0067] In some embodiments, the LUMO energy level of the first hole control sub-layer 131 is equal to the LUMO energy level of the second hole control sub-layer 132 .

[0068] Specifically, the greater the LUMO energy level difference between the first sub-hole control layer 131 and the second sub-hole control layer 132 and the hole transport layer 120, the better it can prevent electrons from crossing the LUMO energy levels of the first sub-hole control layer 131 and the second sub-hole control layer 132, and the better the effect of blocking electrons from jumping from the light-emitting material layer 140 to the hole transport layer 120, thereby preventing the luminous efficiency from decreasing.

[0069] Example 4

[0070] In some embodiments, as shown in FIG. 4 , the first sub-hole control layer 131 is disposed between the second sub-hole control layer 132 and the light emitting material layer 140 .

[0071] In some embodiments, the HOMO energy level of the first sub-hole control layer 131 is lower than the HOMO energy level of the light-emitting material layer 140 ; ​​the LUMO energy level of the first sub-hole control layer 131 is higher than the LUMO energy level of the light-emitting material layer 140 and lower than the LUMO energy level of the hole transport layer 120 .

[0072] Specifically, as shown in Figure 6, the HOMO energy level of the first sub-hole control layer 131 is lower than the HOMO energy level of the light-emitting material layer 140, and a potential barrier difference is formed between the hole transport layer 120 and the second sub-hole control layer 132. A potential barrier difference is formed between the first sub-hole control layer 131 and the second sub-hole control layer 132, forming two deep HOMO energy level traps, which increases the hole injection barrier and requires a larger voltage for hole transport or positive carrier transport to occur, thereby increasing the turn-on voltage of the light-emitting device or display panel.

[0073] Specifically, the LUMO energy level of the first sub-hole control layer 131 is greater than the LUMO energy level of the light-emitting material layer 140 and less than the LUMO energy level of the hole transport layer 120, which can block electrons from jumping from the light-emitting material layer 140 to the hole transport layer 120, thereby preventing the luminous efficiency from decreasing.

[0074] In some embodiments, the LUMO energy level of the first hole control sub-layer 131 is equal to the LUMO energy level of the second hole control sub-layer 132 .

[0075] Specifically, the greater the LUMO energy level difference between the first sub-hole control layer 131 and the second sub-hole control layer 132 and the hole transport layer 120, the better it can prevent electrons from crossing the LUMO energy levels of the first sub-hole control layer 131 and the second sub-hole control layer 132, and the better the effect of blocking electrons from jumping from the light-emitting material layer 140 to the hole transport layer 120, thereby preventing the luminous efficiency from decreasing.

[0076] Example 5

[0077] The display panel of this embodiment is the same as or similar to any one of the above embodiments, except that the features of the display panel are further described.

[0078] In some embodiments, the thickness of the first hole-controlling sub-layer is in a range from 3 nm to 10 nm.

[0079] Specifically, the thickness of the first sub-hole control layer 131 is greater than or equal to 3 nanometers and less than or equal to 10 nanometers. Considering the mass production process, the thickness of an organic layer that is too thin fluctuates greatly, which can easily cause unstable device performance. In addition, in order to form an effective hole blocking barrier, the first sub-hole control layer 131 usually needs to be more than 3 nanometers thick. The smaller the energy level difference, the thicker the required thickness. Therefore, in order to simultaneously meet the film stability of the first sub-hole control layer 131 and form an effective hole blocking barrier, the thickness of the first sub-hole control layer 131 is set to be greater than or equal to 3 nanometers and less than or equal to 10 nanometers.

[0080] In some embodiments, the LUMO energy level of the second sub-hole control layer 132 is greater than the LUMO energy level of the light-emitting material layer 140 and less than the LUMO energy level of the hole transport layer 120; the energy level difference between the LUMO energy level of the second sub-hole control layer 132 and the LUMO energy level of the light-emitting material layer 140 is greater than or equal to 0.2 eV.

[0081] Specifically, the LUMO energy level of the second sub-hole control layer 132 is greater than the LUMO energy level of the light-emitting material layer 140, and less than the LUMO energy level of the hole transport layer 120; the energy level difference between the LUMO energy level of the second sub-hole control layer 132 and the LUMO energy level of the light-emitting material layer 140 is greater than or equal to 0.2 eV, which can effectively block electrons from jumping from the light-emitting material layer 140 to the hole transport layer 120, thereby preventing the luminescence efficiency from decreasing.

[0082] It should be noted that, in the display panel 100 of any of the above embodiments, the display panel 100 may include a red light-emitting device, a green light-emitting device and a blue light-emitting device, and at least one of the red light-emitting device, the green light-emitting device and the blue light-emitting device adopts the light-emitting device of any of the above embodiments.

[0083] Please refer to Figure 7, which is a schematic diagram of the measured operating voltage curve of the improved light-emitting device or display panel provided in an embodiment of the present application. The light-emitting device or display panel before the improvement is shown in the prior art, while the light-emitting device or display panel 100 after the improvement is shown in the above embodiment. As can be seen from the figure, the turn-on voltage of the improved light-emitting device or display panel 100 is increased compared to the light-emitting device or display panel before the improvement, while the stable operating voltage of the improved light-emitting device or display panel 100 remains the same as before the improvement. In other words, the light-emitting device or display panel 100 of the embodiment of the present application has the effect of increasing the turn-on voltage while maintaining the operating voltage.

[0084] It should be noted that the light-emitting device can be arranged on the substrate 11, and the hole transport layer 120 can be composed of a hole injection sublayer 121 and a hole transport sublayer 122; an electron transport layer 160 is arranged between the light-emitting material layer 140 and the second electrode 170, and the electron transport layer 160 can be composed of an electron injection sublayer 162 and an electron transport sublayer 161.

[0085] It should be noted that the luminescent material layer 140 can be composed of a host material and a luminescent dopant. The host material can be a single material, a P / N hybrid material, or a deuterated material; the luminescent dopant can be a phosphorescent, fluorescent, or delayed fluorescent luminescent material. The hole injection sublayer 121 can be a hole transport material doped with a P-type dopant such as Hat-Cn. The electron injection sublayer 162 can be metal Yb or a metal compound such as LiF. The first electrode 110 can be metal Au, silver nanowires, or metal oxide ITO. The second electrode 170 can be metal Ag, Mg, Al, Ca, or a mixed alloy thereof.

[0086] The above is a detailed introduction to a display panel provided in an embodiment of the present application. Specific examples are used herein to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method of the present application and its core idea. At the same time, for those skilled in the art, based on the ideas of the present application, there may be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A display panel, wherein: include: a first electrode; A hole transport layer, disposed on the first electrode; A hole control layer, disposed on the hole transport layer; A light-emitting material layer is disposed on the hole control layer; A second electrode is disposed on the light-emitting material layer; The hole control layer includes a first sub-hole control layer and a second sub-hole control layer, the thickness of the first sub-hole control layer is less than the thickness of the second sub-hole control layer, and the energy level difference between the HOMO energy levels of the first sub-hole control layer and the second sub-hole control layer is greater than or equal to 0.2 eV, The HOMO energy level of the second sub-hole control layer is greater than the HOMO energy level of the light-emitting material layer, and is less than the HOMO energy level of the hole transport layer.

2. The display panel according to claim 1, wherein: The hole mobility of the first hole control sub-layer is smaller than the hole mobility of the second hole control sub-layer.

3. The display panel according to claim 2, wherein: A ratio of the hole mobility of the first hole control sub-layer to the hole mobility of the second hole control sub-layer is less than or equal to 0.

8.

4. The display panel according to claim 1, wherein: The first sub-hole control layer is disposed between the hole transport layer and the second sub-hole control layer.

5. The display panel according to claim 4, wherein: The HOMO energy level of the first sub-hole control layer is greater than the HOMO energy level of the light-emitting material layer, and is less than the HOMO energy level of the second sub-hole control layer; The LUMO energy level of the first hole control sub-layer is greater than the LUMO energy level of the light-emitting material layer, and is less than the LUMO energy levels of the second hole control sub-layer and the hole transport layer.

6. The display panel according to claim 4, wherein: The HOMO energy level of the first sub-hole control layer is greater than the HOMO energy level of the hole transport layer; The LUMO energy level of the first sub-hole control layer is greater than the LUMO energy levels of the light-emitting material layer, the second sub-hole control layer, and the hole transport layer.

7. The display panel according to claim 1, wherein: The first sub-hole control layer is disposed between the second sub-hole control layer and the light emitting material layer.

8. The display panel according to claim 7, wherein: The HOMO energy level of the first sub-hole control layer is greater than the HOMO energy level of the second sub-hole control layer, and is less than the HOMO energy level of the hole transport layer; The LUMO energy level of the first sub-hole control layer is greater than the LUMO energy level of the light-emitting material layer, and is less than the LUMO energy level of the hole transport layer.

9. The display panel according to claim 7, wherein: The HOMO energy level of the first sub-hole control layer is lower than the HOMO energy level of the light-emitting material layer; The LUMO energy level of the first sub-hole control layer is greater than the LUMO energy level of the light-emitting material layer, and is less than the LUMO energy level of the hole transport layer.

10. The display panel according to claim 8, wherein: The LUMO energy level of the first sub-hole control layer is equal to the LUMO energy level of the second sub-hole control layer.

11. The display panel according to claim 9, wherein: The LUMO energy level of the first sub-hole control layer is equal to the LUMO energy level of the second sub-hole control layer.

12. The display panel according to claim 1, wherein: The thickness of the first sub-hole control layer is in a range of 3 nanometers to 10 nanometers.

13. The display panel according to claim 1, wherein: The LUMO energy level of the second sub-hole control layer is greater than the LUMO energy level of the light-emitting material layer, and less than the LUMO energy level of the hole transport layer; An energy level difference between the LUMO energy level of the second sub-hole control layer and the LUMO energy level of the light-emitting material layer is greater than or equal to 0.2 eV.

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