Display panel and display device

Abstract

The invention discloses a display panel and a display device.The display panel comprises a substrate and a light-emitting layer, the light-emitting layer is arranged on one side of the substrate, the light-emitting layer comprises a plurality of light-emitting elements, and each light-emitting element comprises a first electrode, at least one light-emitting unit and a second electrode which are sequentially arranged in a stacked mode; each light-emitting unit comprises a light-emitting material layer and a hole transport layer; wherein the plurality of light-emitting elements comprise a first light-emitting element and a second light-emitting element, the first light-emitting element comprises a first hole transport layer, and the second light-emitting element comprises a second hole transport layer; the stacking sequence of the light-emitting unit where the first hole transport layer is located in the first light-emitting element is the same as the stacking sequence of the light-emitting unit where the second hole transport layer is located in the second light-emitting element, and the refractive index of the first hole transport layer is different from the refractive index of the second hole transport layer. According to the design, the optical coupling extraction efficiency of the display panel can be improved, and the brightness can be improved.

Description

Technical Field

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

[0002] With the development and popularization of display technology in recent years, display panels have been applied to various electronic devices, such as mobile phones, tablet computers or other portable electronic devices.

[0003] However, the light extraction efficiency and brightness of display panels still need to be further improved. Summary of the invention

[0004] The present application mainly provides a display panel and a display device, which can improve the light coupling extraction efficiency of the display panel and increase the brightness.

[0005] In order to solve the above technical problems, the technical solution adopted in the present application is: to provide a display panel, which includes a substrate and a light-emitting layer, wherein the light-emitting layer is arranged on one side of the substrate, and the light-emitting layer includes a plurality of light-emitting elements, and the light-emitting elements include a first electrode, at least one light-emitting unit and a second electrode which are stacked in sequence, and each of the light-emitting units includes a light-emitting material layer and a hole transport layer; wherein the plurality of light-emitting elements include a first light-emitting element and a second light-emitting element, the first light-emitting element includes a first hole transport layer, and the second light-emitting element includes a second hole transport layer, and the stacking order of the light-emitting unit where the first hole transport layer is located in the first light-emitting element and the stacking order of the light-emitting unit where the second hole transport layer is located in the second light-emitting element are the same, wherein the refractive index of the first hole transport layer is different from the refractive index of the second hole transport layer.

[0006] In order to solve the above technical problems, another technical solution adopted in the present application is: providing a display panel, the display panel comprising: a substrate; a light-emitting layer, arranged on one side of the substrate, the light-emitting layer comprising a plurality of light-emitting elements, the light-emitting elements comprising a first electrode, at least one light-emitting unit and a second electrode stacked in sequence, each of the light-emitting units comprising a light-emitting material layer and a hole transport layer; an isolation structure, arranged on the side of the light-emitting layer away from the substrate, the isolation structure having a plurality of isolation openings, the orthographic projection of the isolation opening on the substrate at least partially overlapping with the orthographic projection of the light-emitting element on the substrate; wherein the plurality of light-emitting elements comprise a first light-emitting element and a second light-emitting element, and the refractive index of the hole transport layer in the first light-emitting element and the refractive index of the hole transport layer in the second light-emitting element are different.

[0007] In order to solve the above technical problem, another technical solution adopted by the present application is: to provide a display device, which includes the display panel described in the above embodiment.

[0008] The beneficial effect of the present application is that the light coupling extraction efficiency of the display panel can be improved and the brightness can be increased by designing that the refractive index of the first hole transport layer is different from the refractive index of the second hole transport layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. Among them:

[0010] Figure 1 This is a schematic structural diagram of an embodiment of a display panel of the present application;

[0011] Figure 2 This is a schematic structural diagram of another embodiment of the display panel of the present application;

[0012] Figure 3 It is a simple schematic diagram of the relationship between the current efficiency of a single-layer light-emitting device with a first-order microcavity structure and the thickness and refractive index of the hole transport layer;

[0013] Figure 4 This is a simple schematic diagram of the relationship between the current efficiency, light coupling extraction efficiency and the refractive index of the hole transport layer of a single-layer red light-emitting device with a second-order microcavity structure;

[0014] Figure 5 This is a simple schematic diagram of the relationship between the current efficiency, light coupling extraction efficiency and the refractive index of the hole transport layer of a single-layer green light-emitting device with a second-order microcavity structure;

[0015] Figure 6 This is a simple schematic diagram of the relationship between the blue index, light coupling extraction efficiency and the refractive index of the hole transport layer of a single-layer blue light-emitting device with a second-order microcavity structure;

[0016] Figure 7 This is a schematic structural diagram of another embodiment of the display panel of the present application;

[0017] Figure 8 This is a schematic structural diagram of yet another embodiment of the display panel of the present application. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions 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 ordinary technicians in this field without creative work are within the scope of protection of this application.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0020] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0021] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0022] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0023] See also Figure 1The present application provides a display panel, which includes a substrate 10 and a light-emitting layer 20, wherein the light-emitting layer 20 is arranged on one side of the substrate 10, and the light-emitting layer 20 includes a plurality of light-emitting elements 21, and the light-emitting element 21 includes a first electrode 22, at least one light-emitting unit 23 and a second electrode 24 which are stacked in sequence, and each light-emitting unit 23 includes a light-emitting material layer 231 and a hole transport layer 232; wherein the plurality of light-emitting elements 21 include a first light-emitting element 211 and a second light-emitting element 212, the first light-emitting element 211 includes a first hole transport layer 2321, and the second light-emitting element 212 includes a second hole transport layer 2322, and the stacking order of the light-emitting unit 23 where the first hole transport layer 2321 is located in the first light-emitting element 211 and the stacking order of the light-emitting unit 23 where the second hole transport layer 2322 is located in the second light-emitting element 212 are the same, wherein the refractive index of the first hole transport layer 2321 is different from the refractive index of the second hole transport layer 2322.

[0024] Specifically, the substrate 10 plays a major supporting role in the display panel. The substrate 10 includes a substrate 11 and a driving circuit layer. The light-emitting layer 20 is located on the side of the driving circuit layer away from the substrate. The substrate plays a supporting role in the display panel. It can be a flexible substrate or a rigid substrate. When the substrate is a flexible substrate, its material can be polyimide (PI). When the substrate is a rigid substrate, its material can be glass or metal. This application does not limit the structure of the substrate.

[0025] Wherein, the driving circuit layer includes a pixel driving circuit, and the pixel driving circuit is used to drive the light-emitting element 21 to emit light. The pixel driving circuit includes structures such as a transistor and a capacitor, and the transistor includes a semiconductor, a gate, a source and a drain. The capacitor includes a first plate and a second plate. Wherein the pixel driving circuit can be, for example, a 2T1C circuit, a 7T1C circuit, a 7T2C circuit or a 9T1C circuit, etc., and the present application does not limit its specific structure. Wherein "2T1C circuit" refers to a pixel circuit including 2 thin film transistors (T) and 1 capacitor (C) in the pixel circuit, and other "7T1C circuit", "7T2C circuit", "9T1C circuit" and the like are deduced in turn.

[0026] The multiple light-emitting elements 21 in the light-emitting layer 20 can realize the function of emitting light. In the direction away from the substrate 10, the first electrode 22, at least one light-emitting unit 23 and the second electrode 24 in the light-emitting element 21 are stacked in sequence, wherein when the first electrode 22 is an anode, the second electrode 24 is a cathode, and when the first electrode 22 is a cathode, the second electrode 24 is an anode.

[0027] The number of the light emitting unit 23 can be one or more, for example, two. Figure 1The number of light-emitting units 23 is one for illustration. Each light-emitting unit 23 includes a light-emitting material layer 231 and a hole transport layer 232. The hole transport layer 232 is used by the light-emitting material layer 231 to transport holes required for light emission. The light-emitting unit 23 also includes an electron transport layer 233. The electron transport layer 233 is used by the light-emitting material layer 231 to transport electrons required for light emission. After the electrons and holes are combined in the light-emitting material layer 231, the light-emitting material layer 231 emits light.

[0028] In one embodiment, if Figure 1 As shown, the light-emitting unit 23 includes, in addition to the hole transport layer 232, the electron transport layer 233, and the light-emitting material layer 231, a hole injection layer 234, an electron blocking layer 235, a hole blocking layer 236, an electron injection layer 237 and other film layers, and in Figure 1 In the embodiment, the first electrode 22 is an anode and the second electrode 24 is a cathode. At this time, in the direction away from the substrate 11, the first electrode 22, the hole injection layer 234, the hole transport layer 232, the electron blocking layer 235, the light-emitting material layer 231, the hole blocking layer 236, the electron transport layer 233, the electron injection layer 237, and the second electrode 24 are stacked in sequence. It can be understood that when in other embodiments, the first electrode 22 is a cathode and the second electrode 24 is an anode, in the direction close to the substrate 11, the second electrode 24, the hole injection layer 234, the hole transport layer 232, the electron blocking layer 235, the light-emitting material layer 231, the hole blocking layer 236, the electron transport layer 233, the electron injection layer 237, and the first electrode 22 are stacked in sequence. For the sake of convenience, the following figures are schematically illustrated with the first electrode 22 as the anode and the second electrode 24 as the cathode.

[0029] Meanwhile, in this embodiment, two of the plurality of light emitting elements 21 are respectively defined as a first light emitting element 211 and a second light emitting element 212. The first light emitting element 211 includes a first hole transport layer 2321, and the second light emitting element 212 includes a second hole transport layer 2322.

[0030] Among them, the stacking order of the light-emitting unit 23 where the first hole transport layer 2321 is located in the first light-emitting element 211 and the stacking order of the light-emitting unit 23 where the second hole transport layer 2322 is located in the second light-emitting element 212 are the same means: in the direction away from the substrate 11, if the light-emitting unit 23 where the first hole transport layer 2321 is located is the first light-emitting unit 23 in the first light-emitting element 211 (that is, if the light-emitting unit 23 where the first hole transport layer 2321 is located is the light-emitting unit 23 closest to the substrate 11 in the first light-emitting element 211), then in the direction away from the substrate 11, the light-emitting unit 23 where the second hole transport layer 2322 is located is also the first light-emitting unit 23 in the second light-emitting element 212; in the direction away from the substrate 11, if the light-emitting unit 23 where the first hole transport layer 2321 is located is the second light-emitting unit 23 in the first light-emitting element 211, then in the direction away from the substrate 11, the light-emitting unit 23 where the second hole transport layer 2322 is located is also the second light-emitting unit 23 in the second light-emitting element 212, and so on.

[0031] In the related art, the refractive index of the hole transport layer 232 in all light-emitting elements 21 is the same, and the refractive index of the hole transport layer 232 cannot be adjusted for different light-emitting elements 21. Therefore, the light coupling extraction efficiency of the display panel is limited to a certain extent, thereby affecting the brightness of the display panel.

[0032] However, in this embodiment, the refractive index of the first hole transport layer 2321 is set to be different from the refractive index of the second hole transport layer 2322, which can improve the light output mode of the display panel and enhance the light coupling extraction efficiency and brightness of the display panel.

[0033] In one embodiment, the light emitting color of the first light emitting element 211 is different from the light emitting color of the second light emitting element 212. For example, the light emitting color of the first light emitting element 211 is red, and the light emitting color of the second light emitting element 212 is green, or the light emitting color of the first light emitting element 211 is green, and the light emitting color of the second light emitting element 212 is blue. In other embodiments, the light emitting color of the first light emitting element 211 and the light emitting color of the second light emitting element 212 may also be the same.

[0034] In one embodiment, the thickness of the first hole transport layer 2321 is different from the thickness of the second hole transport layer 2322. Specifically, while setting the refractive index of the first hole transport layer 2321 to be different from the refractive index of the second hole transport layer 2322, the thickness of the first hole transport layer 2321 is also set to be different from the thickness of the second hole transport layer 2322, which can further improve the light output mode of the display panel and achieve the effect of improving the light coupling extraction efficiency. Of course, in other embodiments, the thickness of the first hole transport layer 2321 and the thickness of the second hole transport layer 2322 can also be the same.

[0035] See also Figure 2 , the multiple light-emitting elements 21 further include a third light-emitting element 213, the third light-emitting element 213 includes a third hole transport layer 2323, the stacking order of the light-emitting unit 23 where the third hole transport layer 2323 is located in the third light-emitting element 213, the stacking order of the light-emitting unit 23 where the first hole transport layer 2321 is located in the first light-emitting element 211, and the stacking order of the light-emitting unit 23 where the second hole transport layer 2322 is located in the second light-emitting element 212 are the same, wherein the refractive index of the third hole transport layer 2323 is different from the refractive index of the first hole transport layer 2321, and the refractive index of the third hole transport layer 2323 is different from the refractive index of the second hole transport layer 2322.

[0036] Specifically, in the direction away from the substrate 11, if the light-emitting unit 23 where the first hole transport layer 2321 is located is the first light-emitting unit 23 in the first light-emitting element 211, then in the direction away from the substrate 11, the light-emitting unit 23 where the second hole transport layer 2322 is located is also the first light-emitting unit 23 in the second light-emitting element 212, and the light-emitting unit 23 where the third hole transport layer 2323 is also the first light-emitting unit 23 in the third light-emitting element 213; in the direction away from the substrate 11, if the light-emitting unit 23 where the first hole transport layer 2321 is located is the second light-emitting unit 23 in the first light-emitting element 211, then in the direction away from the substrate 11, the light-emitting unit 23 where the second hole transport layer 2322 is located is also the second light-emitting unit 23 in the second light-emitting element 212, and the light-emitting unit 23 where the third hole transport layer 2323 is also the second light-emitting unit 23 in the third light-emitting element 213, and so on.

[0037] In this embodiment, the refractive indices of the first hole transport layer 2321 , the second hole transport layer 2322 , and the third hole transport layer 2323 are all different, which can further improve the light coupling efficiency of the display panel.

[0038] In other embodiments, only the refractive index of the third hole transport layer 2323 may be different from the refractive index of the first hole transport layer 2321, while the refractive index of the third hole transport layer 2323 may be the same as the refractive index of the second hole transport layer 2322; or only the refractive index of the third hole transport layer 2323 may be different from the refractive index of the second hole transport layer 2322, while the refractive index of the third hole transport layer 2323 may be the same as the refractive index of the first hole transport layer 2321.

[0039] In one embodiment, the thickness of the third hole transport layer 2323 is different from the thickness of the first hole transport layer 2321 , so as to further improve the light extraction effect of the display panel.

[0040] In one embodiment, the thickness of the third hole transport layer 2323 is different from the thickness of the second hole transport layer 2322 , so as to further improve the light extraction effect of the display panel.

[0041] In one embodiment, the thicknesses of the first hole transport layer 2321 , the second hole transport layer 2322 , and the third hole transport layer 2323 are all different.

[0042] In one embodiment, the plurality of light emitting elements 21 are divided into a plurality of repeated pixel units, and the pixel unit includes a first light emitting element 211, a second light emitting element 212, and a third light emitting element 213. At this time, the first light emitting element 211, the second light emitting element 212, and the third light emitting element 213 are in the same pixel unit.

[0043] In one embodiment, the first light emitting element 211, the second light emitting element 212, and the third light emitting element 213 emit different colors of light, for example, the first light emitting element 211, the second light emitting element 212, and the third light emitting element 213 emit red, green, and blue colors, respectively.

[0044] In one embodiment, the first light-emitting element 211 and the second light-emitting element 212 each include a light-emitting unit 23, that is, the first light-emitting element 211 and the second light-emitting element 212 are both single-layer light-emitting devices, and the first light-emitting element 211 and the second light-emitting element 212 both have a first-order microcavity structure, wherein the refractive index of the hole transport layer 232 in the first light-emitting element 211 is less than the refractive index of the hole transport layer 232 in the second light-emitting element 212.

[0045] Specifically, when the light emitting element 21 includes only one light emitting unit 23 and the light emitting element 21 has a first-order microcavity structure, refer to Figure 3 , Figure 3 The refractive index of the hole transport layer 232 corresponding to different curves is different. Figure 3 The refractive indices of the hole transport layer 232 corresponding to the six curves are 1.5, 1.6, 1.7, 1.8, 1.9, and 2). Figure 3 It can be seen that when the thickness of the hole transport layer 232 is fixed, the refractive index of the hole transport layer 232 decreases and the current efficiency (CE) increases. Therefore, in this embodiment, the refractive index of the hole transport layer 232 in the first light-emitting element 211 is set to be smaller than the refractive index of the hole transport layer 232 in the second light-emitting element 212, thereby improving the current efficiency of the first light-emitting element 211 and the light coupling extraction efficiency of the first light-emitting element 211, thereby improving the light coupling extraction efficiency of the display panel.

[0046] Optionally, in this implementation, the thickness of the hole transport layer 232 in the first light-emitting element 211 is smaller than the thickness of the hole transport layer 232 in the second light-emitting element 212 .

[0047] Specifically, from Figure 3 It can also be seen that when the refractive index of the hole transport layer 232 is fixed, the thickness of the hole transport layer 232 decreases and the current efficiency increases. Therefore, in this embodiment, the thickness of the hole transport layer 232 in the first light-emitting element 211 is set to be smaller than the thickness of the hole transport layer 232 in the second light-emitting element 212, thereby further improving the light coupling extraction efficiency of the first light-emitting element 211, thereby further improving the light coupling extraction efficiency of the display panel.

[0048] Meanwhile, in this embodiment, the light emitting colors of the first light emitting element 211 and the second light emitting element 212 may be the same or different.

[0049] In another embodiment, the first light-emitting element 211 and the second light-emitting element 212 each include a light-emitting unit 23, and the first light-emitting element 211 and the second light-emitting element 212 each have a second-order microcavity structure, wherein the refractive index of the hole transport layer 232 in the first light-emitting element 211 is greater than the refractive index of the hole transport layer 232 in the second light-emitting element 212.

[0050] Specifically, when the light emitting element 21 includes only one light emitting unit 23 and the light emitting element 21 has a second-order microcavity structure, Figure 4-Figure 6 It can be seen that when the thickness of the hole transport layer 232 is fixed, the refractive index of the hole transport layer 232 increases, the current efficiency (CE) and the light coupling extraction efficiency (I_OC) of the red light emitting element 21 and the green light emitting element 21 are both increased, and the blue index (BI) and the light coupling extraction efficiency (I_OC) of the blue light emitting element 21 are both increased. Therefore, in this embodiment, the refractive index of the hole transport layer 232 in the first light emitting element 211 is set to be greater than the refractive index of the hole transport layer 232 in the second light emitting element 212, thereby improving the current efficiency of the first light emitting element 211, improving the light coupling extraction efficiency of the first light emitting element 211, and thus improving the light coupling extraction efficiency of the display panel.

[0051] Optionally, in this embodiment, the thickness of the hole transport layer 232 in the first light-emitting element 211 is smaller than the thickness of the hole transport layer 232 in the second light-emitting element 212 .

[0052] Specifically, when the light-emitting element 21 includes only one light-emitting unit 23 and the light-emitting element 21 has a second-order microcavity structure, when the refractive index of the hole transport layer 232 is fixed, the thickness of the hole transport layer 232 decreases and the current efficiency increases. Therefore, in this embodiment, the thickness of the hole transport layer 232 in the first light-emitting element 211 is set to be smaller than the thickness of the hole transport layer 232 in the second light-emitting element 212, thereby further improving the light coupling extraction efficiency of the first light-emitting element 211, thereby further improving the light coupling extraction efficiency of the display panel.

[0053] In another embodiment, the first light-emitting element 211 and the second light-emitting element 212 each include a light-emitting unit 23, that is, the first light-emitting element 211 and the second light-emitting element 212 are both single-layer light-emitting devices, and the first light-emitting element 211 has a first-order microcavity structure and the second light-emitting element 212 has a second-order microcavity structure, wherein the refractive index of the hole transport layer 232 in the first light-emitting element 211 is less than the refractive index of the hole transport layer 232 in the second light-emitting element 212.

[0054] Specifically, through the above analysis, it can be known that when the light-emitting element 21 is a single-layer light-emitting device and has a first-order microcavity structure, the refractive index of the hole transport layer 232 decreases and the current efficiency (CE) increases, and when the light-emitting element 21 is a single-layer device and has a second-order microcavity structure, the refractive index of the hole transport layer 232 increases, the current efficiency (CE) increases, and the light coupling extraction efficiency (I_OC) also increases. Therefore, in this embodiment, the refractive index of the hole transport layer 232 in the first light-emitting element 211 is set to be smaller than the refractive index of the hole transport layer 232 in the second light-emitting element 212, that is, the hole transport layer 232 in the first light-emitting element 211 is set to have a small refractive index, and the hole transport layer 232 in the second light-emitting element 212 is set to have a large refractive index, while ensuring that the first light-emitting element 211 and the second light-emitting element 212 have high light coupling extraction efficiency, thereby ensuring the light coupling extraction efficiency of the display panel.

[0055] Optionally, in this embodiment, the refractive index of the hole transport layer 232 in the first light-emitting element 211 is in the range of 1.4 to 1.7, for example, 1.4, 1.5, 1.6 or 1.7.

[0056] Optionally, in this embodiment, the refractive index of the hole transport layer 232 in the second light-emitting element 212 is in the range of 1.8 to 2.5, for example, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4 or 2.5.

[0057] In another embodiment, the first light-emitting element 211 and the second light-emitting element 212 each include a light-emitting unit 23, the first light-emitting element 211 has a first-order microcavity structure, and the second light-emitting element 212 has a second-order microcavity structure, wherein the thickness of the hole transport layer 232 in the first light-emitting element 211 is less than the thickness of the hole transport layer 232 in the second light-emitting element 212.

[0058] Specifically, it can be seen from the above analysis that when the light-emitting element 21 is a single-layer device and has a first-order microcavity structure, the thickness of the hole transport layer 232 decreases and the current efficiency increases. Therefore, in this embodiment, the thickness of the hole transport layer 232 in the first light-emitting element 211 is set to be smaller than the thickness of the hole transport layer 232 in the second light-emitting element 212, that is, in the first light-emitting element 211 which is a single-layer device and has a first-order microcavity structure, the hole transport layer 232 has a small thickness, thereby ensuring that the first light-emitting element 211 has a high light coupling extraction efficiency, thereby ultimately improving the light coupling extraction efficiency of the display panel.

[0059] Optionally, in this embodiment, the thickness of the hole transport layer 232 in the first light-emitting element 211 ranges from 10 to 30 nm, for example, the thickness is 10 nm, 15 nm, 20 nm, 25 nm, or 30 nm.

[0060] Optionally, in this embodiment, the thickness of the hole transport layer 232 in the second light-emitting element 212 is in the range of 90 to 140 nm, for example, the thickness is 90 nm, 100 nm, 110 nm, 120 nm, 130 nm or 140 nm.

[0061] Optionally, in this embodiment, when the light emitting color of the second light emitting element 212 is red, the thickness of the hole transport layer 232 in the second light emitting element 212 is in the range of 90 to 140 nm, for example, 90 nm, 100 nm, 110 nm, 120 nm, 130 nm or 140 nm.

[0062] Optionally, in this embodiment, when the light emitting color of the second light emitting element 212 is green, the thickness of the hole transport layer 232 in the second light emitting element 212 is in the range of 100 to 130 nm, for example, the thickness is 100 nm, 110 nm, 120 nm or 130 nm.

[0063] Optionally, in this embodiment, when the light emitting color of the second light emitting element 212 is blue, the thickness of the hole transport layer 232 in the second light emitting element 212 is in the range of 105 to 130 nm, for example, the thickness is 105 nm, 110 nm, 115 nm, 120 nm, 125 nm or 130 nm.

[0064] In another embodiment, the light-emitting element 21 includes a light-emitting unit 23, that is, the light-emitting element 21 is a single-layer light-emitting device, and the light-emitting element 21 has a first-order microcavity structure, wherein the refractive index of the hole transport layer 232 in the light-emitting element 21 ranges from 1.4 to 1.7. For example, the specific refractive index of the hole transport layer 232 may be 1.4, 1.5, 1.6 or 1.7. At the same time, the thickness of the hole transport layer 232 in the light-emitting element 21 ranges from 10 to 30 nm. For example, the thickness of the hole transport layer 232 may be 10 nm, 15 nm, 20 nm, 25 nm, or 30 nm.

[0065] Specifically, in the first-order microcavity structure, the positions of the light-emitting material layer 231 and the hole transport layer 232 are relatively close to the first electrode 22. For the hole transport layer 232 of the first-order microcavity close to the first electrode 22, the smaller the refractive index and the thickness of the hole transport layer 232 are, the power dissipation is mainly shifted from the evanescent wave mode and the absorption mode to the light output mode of optical coupling extraction, which can reduce the influence of the evanescent wave mode and the waveguide mode. Therefore, the above-mentioned embodiment sets the refractive index range of the hole transport layer 232 to 1.4~1.7 and the thickness range of the hole transport layer 232 to 10~30nm. Setting the hole transport layer 232 to a low refractive index and a low thickness can effectively improve the optical coupling extraction efficiency.

[0066] It should be noted that, in other embodiments, the refractive index of the hole transport layer 232 may be set to be in the range of 1.4 to 1.7 without limiting the thickness of the hole transport layer 232. Alternatively, in other embodiments, the thickness of the hole transport layer 232 may be set to be in the range of 10 to 30 nm without limiting the refractive index of the hole transport layer 232.

[0067] In another embodiment, the light-emitting element 21 includes a light-emitting unit 23, and the light-emitting element 21 has a second-order microcavity structure, wherein the refractive index of the hole transport layer 232 in the light-emitting element 21 ranges from 1.8 to 2.5. For example, the refractive index of the hole transport layer 232 may be 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4 or 2.5. At the same time, the thickness of the hole transport layer 232 in the light-emitting element 21 ranges from 90 to 140 nm. For example, the thickness of the hole transport layer 232 may be 90 nm, 100 nm, 110 nm, 120 nm, 130 nm or 140 nm.

[0068] Specifically, in the second-order microcavity structure, in order to improve the evanescent wave mode brought about by the proximity of the light-emitting material layer 231 to the first electrode 22 and improve the light coupling extraction efficiency, the hole transport layer 232 needs to be kept away from the first electrode 22, that is, the hole transport layer 232 is placed at the position of the second-order microcavity. As the refractive index of the hole transport layer 232 increases and the thickness decreases, the light absorption mode can be improved, the light coupling extraction efficiency can be improved, and the current efficiency (CE) and external quantum efficiency (EQE) can also be improved. Therefore, in order to place the hole transport layer 232 at the second-order microcavity position, the hole transport layer 232 is set to have a larger refractive index and a lower thickness in this embodiment, that is, the refractive index range of the hole transport layer 232 is set to 1.8 to 2.5, and the thickness range is 90 to 140 nm.

[0069] Optionally, in this embodiment, when the light emitting color of the light emitting element 21 is red, the thickness of the hole transport layer 232 in the light emitting element 21 is in the range of 90 to 140 nm. For example, the thickness of the hole transport layer 232 in the red light emitting element 21 can be 90 nm, 100 nm, 110 nm, 120 nm, 130 nm or 140 nm to improve the red light emitting effect.

[0070] Optionally, in this embodiment, when the light emitting color of the light emitting element 21 is green, the thickness of the hole transport layer 232 in the light emitting element 21 is in the range of 100 to 130 nm. For example, the thickness of the hole transport layer 232 in the green light emitting element 21 can be 100 nm, 110 nm, 120 nm or 130 nm to improve the green light emitting effect.

[0071] Optionally, in this embodiment, when the light emitting color of the light emitting element 21 is blue, the thickness of the hole transport layer 232 in the light emitting element 21 is in the range of 105 to 130 nm. For example, the thickness of the hole transport layer 232 in the blue light emitting element 21 can be 105 nm, 110 nm, 115 nm, 120 nm, 125 nm or 130 nm to improve the blue light emitting effect.

[0072] See also Figure 7 In another embodiment, the light emitting element 21 includes a plurality of light emitting units 23, that is, the light emitting element 21 is a stacked device, and the plurality of light emitting units 23 include a first light emitting unit 26 and a second light emitting unit 27, wherein the refractive index of the hole transport layer 232 in the first light emitting unit 26 is different from the refractive index of the hole transport layer 232 in the second light emitting unit 27. Specifically, the design of different refractive indices of the hole transport layer 232 in different light emitting units 23 in the same light emitting element 21 is conducive to further improving the light coupling and extraction efficiency of the display panel.

[0073] Optionally, in this embodiment, if Figure 7As shown, the light emitting element 21 includes two light emitting units 23. In other embodiments, the light emitting element 21 may also include three, four, or even more light emitting units 23, which is not limited here.

[0074] Please continue reading Figure 7 Optionally, in this embodiment, the first electrode 22 is an anode, and the first electrode 22, the first light-emitting unit 26, and the second light-emitting unit 27 are stacked in sequence, wherein the refractive index of the hole transport layer 232 in the first light-emitting unit 26 is less than the refractive index of the hole transport layer 232 in the second light-emitting unit 27.

[0075] Specifically, the position of the hole transport layer 232 in the first light-emitting unit 26 is equivalent to the position of the hole transport layer 232 when the light-emitting element 21 is a first-order microcavity structure. Therefore, the refractive index of the hole transport layer 232 in the first light-emitting unit 26 is reduced, so that the power dissipation is mainly turned from the evanescent wave mode and the absorption mode to the light-exit mode of light coupling extraction, which can reduce the influence of the evanescent wave mode and the waveguide mode. The hole transport layer 232 in the second light-emitting unit 27 is far away from the first electrode 22. The hole transport layer 232 in the second light-emitting unit 27 is equivalent to the position of the hole transport layer 232 when the light-emitting element 21 is a second-order microcavity structure. As the refractive index of the hole transport layer 232 increases, the light absorption mode can be improved, the light coupling extraction efficiency can be improved, and the current efficiency (CE) and the external quantum efficiency (EQE) can also be improved. Therefore, the above embodiment sets the refractive index of the hole transport layer 232 in the first light-emitting unit 26 to be less than the refractive index of the hole transport layer 232 in the second light-emitting unit 27.

[0076] Optionally, in this embodiment, the refractive index of the hole transport layer 232 in the first light-emitting unit 26 is in the range of 1.4 to 1.7. For example, the refractive index of the hole transport layer 232 in the first light-emitting unit 26 may be 1.4, 1.5, 1.6 or 1.7. The use of a low refractive index material to prepare the hole transport layer 232 can improve the light emission effect of the display panel. Optionally, in this embodiment, the refractive index of the hole transport layer 232 in the second light-emitting unit 27 is in the range of 1.8 to 2.5. For example, the refractive index of the hole transport layer 232 in the second light-emitting unit 27 may be 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4 or 2.5. The use of a high refractive index material to prepare the hole transport layer 232 can further improve the light emission effect of the display panel.

[0077] Please continue reading Figure 7 Optionally, in this embodiment, the thickness of the hole transport layer 232 in the first light-emitting unit 26 is different from the thickness of the hole transport layer 232 in the second light-emitting unit 27, which is used to further improve the light-emitting effect of the light-emitting element 21 to which the first light-emitting unit 26 and the second light-emitting unit 27 belong.

[0078] Optionally, in this embodiment, the first electrode 22 is an anode, and the first electrode 22, the first light-emitting unit 26, and the second light-emitting unit 27 are stacked in sequence, and the thickness of the hole transport layer 232 in the first light-emitting unit 26 is less than the thickness of the hole transport layer 232 in the second light-emitting unit 27, so as to further improve the light coupling extraction efficiency of the display panel.

[0079] Optionally, in this embodiment, the thickness of the hole transport layer 232 in the first light-emitting unit 26 is in the range of 10 to 30 nm, and the thickness of the hole transport layer 232 in the second light-emitting unit 27 is in the range of 25 to 75 nm. For example, the thickness of the hole transport layer 232 in the first light-emitting unit 26 may be 10 nm, 20 nm, or 30 nm. For example, the thickness of the hole transport layer 232 in the second light-emitting unit 27 may be 25 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, or 75 nm.

[0080] Specifically, in the first light-emitting unit 26 close to the anode, the combination of low refractive index and thickness makes the power dissipation mainly shift from the evanescent wave mode and the absorption mode to the light-emitting mode of optical coupling extraction, thereby reducing the impact of the evanescent wave mode and the waveguide mode and improving the optical coupling extraction efficiency.

[0081] In the second light-emitting unit 27 far from the anode, in order to improve the light absorption mode and enhance the light coupling extraction efficiency, a high refractive index design is adopted, and the thickness is reduced, the light absorption mode is improved to enhance the light coupling extraction efficiency, and the current efficiency (CE) and external quantum efficiency (EQE) are effectively improved, the brightness is also effectively improved, and the chromaticity is less affected.

[0082] Optionally, in this embodiment, when the light emitting color of the light emitting element 21 is red, the thickness of the hole transport layer 232 in the second light emitting unit 27 of the light emitting element 21 is in the range of 25 to 75 nm. For example, the thickness of the hole transport layer 232 in the second light emitting unit 27 of the red light emitting element 21 can be 25 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm or 75 nm.

[0083] Optionally, in this embodiment, when the light emitting color of the light emitting element 21 is green, the thickness of the hole transport layer 232 in the second light emitting unit 27 of the light emitting element 21 is in the range of 30 to 60 nm. For example, the thickness of the hole transport layer 232 in the second light emitting unit 27 of the green light emitting element 21 can be 30 nm, 40 nm, 50 nm or 60 nm.

[0084] Optionally, in this embodiment, when the light emitting color of the light emitting element 21 is blue, the thickness of the hole transport layer 232 in the second light emitting unit 27 of the light emitting element 21 is in the range of 25 to 50 nm. For example, the thickness of the hole transport layer 232 in the second light emitting unit 27 of the blue light emitting element 21 may be 25 nm, 30 nm, 40 nm or 50 nm.

[0085] See also Figure 8 The display panel further includes an isolation structure 30, which is disposed on the side of the light-emitting layer 20 away from the substrate 10. The isolation structure 30 is provided with a plurality of isolation openings 31, and the orthographic projection of the isolation openings 31 on the substrate 10 at least partially overlaps with the orthographic projection of the light-emitting element 21 on the substrate 10. The isolation structure 30 can prevent the light from crosstalking between two adjacent light-emitting elements 21. In one embodiment, the overall structure of the isolation structure 30 is in a grid shape. At the same time, adjacent isolation structures 30 are separated by isolation openings 31.

[0086] In one embodiment, the isolation structure 30 includes a first end 32 close to the substrate 10 and a second end 33 away from the substrate 10, and the orthographic projection of the first end 32 on the substrate 10 is located within the orthographic projection of the second end 33 on the substrate 10. The second end 33 is located on a side of the first end 32 away from the substrate 10, and the orthographic projection of the second end 33 on the substrate 10 at least partially extends beyond the orthographic projection of the first end 32 on the substrate 10. Specifically, the isolation structure 30 is generally wide at the top and narrow at the bottom. In this way, during the preparation process, the functional layers in the light-emitting element 21 (the functional layers include the hole injection layer 234, the hole transport layer 232, the electron blocking layer 235, the light-emitting material layer 231, the hole blocking layer 236, the electron transport layer 233, the electron injection layer 237 and other film layers) can be evaporated on the entire surface first, and at the edge of the isolation structure 30, due to the existence of the step difference, the functional layer of the light-emitting element 21 will be disconnected at the edge of the isolation structure 30, so that the functional layer of the light-emitting element 21 can be completely in the isolation opening 31, so that the preparation of the functional layer does not require precision mask alignment, which can reduce costs.

[0087] In one embodiment, the isolation structure 30 is conductive, and the first electrode 22, at least one light-emitting unit 23, and the second electrode 24 are sequentially stacked in the direction of the substrate 10, wherein the second electrode 24 extends to the side wall of the isolation structure 30 and is electrically connected to the isolation structure 30. Thus, a voltage can be applied to the second electrode 24 through the isolation structure 30, which can reduce the transmission impedance and ensure the uniformity of voltage application, thereby improving the uniformity of display of the display panel.

[0088] Continue reading Figure 8The display panel may further include a pixel definition layer 40, wherein the light emitting element 21 is formed in a pixel opening in the pixel definition layer 40, and the isolation structure 30 is disposed on a side of the pixel definition layer 40 away from the substrate 10. The pixel definition layer 40 is used to define the light emitting element 21 to avoid crosstalk between two adjacent light emitting elements 21.

[0089] Continue reading Figure 1 as well as Figure 8 In another embodiment of the present application, the display panel includes a substrate 110 , a light emitting layer 20 , and an isolation structure 30 .

[0090] The light-emitting layer 20 is arranged on one side of the substrate 110, and the light-emitting layer 20 includes a plurality of light-emitting elements 21. The light-emitting element 21 includes a first electrode 22, at least one light-emitting unit 23 and a second electrode 24 which are stacked in sequence. Each light-emitting unit 23 includes a light-emitting material layer 231 and a hole transport layer 232.

[0091] The isolation structure 30 is disposed on the side of the light emitting layer 20 away from the substrate 110 . The isolation structure 30 is provided with a plurality of isolation openings 31 . The orthographic projections of the isolation openings 31 on the substrate 110 at least partially overlap with the orthographic projections of the light emitting elements 21 on the substrate 110 .

[0092] The plurality of light emitting elements 21 include a first light emitting element 211 and a second light emitting element 212 , and the hole transport layer 232 in the first light emitting element 211 and the hole transport layer 232 in the second light emitting element 212 have different refractive indices.

[0093] Specifically, in this embodiment, as long as there is a hole transport layer 232 in the first light-emitting element 211 and a hole transport layer 232 in the second light-emitting element 212 whose refractive index is different, this setting can also improve the light output mode of the display panel and improve the light coupling extraction efficiency of the display panel.

[0094] The structures of the substrate 110 and the isolation structure 30 are the same as those in the aforementioned embodiment. For details, please refer to the above-mentioned related contents, which will not be repeated here.

[0095] Optionally, in this embodiment, the thickness of the hole transport layer 232 in the first light-emitting element 211 and the thickness of the hole transport layer 232 in the second light-emitting element 212 are different, that is, there is a hole transport layer 232 in the first light-emitting element 211 and a hole transport layer 232 in the second light-emitting element 212 whose thickness is different. This setting can also improve the light output mode of the display panel and improve the light coupling extraction efficiency of the display panel.

[0096] The light emitting colors of the first light emitting element 211 and the second light emitting element 212 may be the same or different, which is not limited here.

[0097] Optionally, in this embodiment, when the light-emitting element 21 includes a light-emitting unit 23 and has a first-order microcavity structure, the refractive index of the hole transport layer 232 in the light-emitting element 21 is in the range of 1.4 to 1.7, for example, 1.4, 1.5, 1.6 or 1.7.

[0098] Optionally, in this embodiment, when the light-emitting element 21 includes a light-emitting unit 23 and the light-emitting element 21 has a first-order microcavity structure, the thickness of the hole transport layer 232 in the light-emitting element 21 ranges from 10 to 30 nm, for example, the thickness is 10 nm, 15 nm, 20 nm, 25 nm or 30 nm.

[0099] Optionally, in this embodiment, when the light-emitting element 21 includes a light-emitting unit 23 and the light-emitting element 21 has a second-order microcavity structure, the refractive index of the hole transport layer 232 in the light-emitting element 21 is in the range of 1.8 to 2.5, for example, the refractive index is 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4 or 2.5, etc.

[0100] Optionally, in this embodiment, when the light-emitting element 21 includes a light-emitting unit 23 and the light-emitting element 21 has a second-order microcavity structure, the thickness of the hole transport layer 232 in the light-emitting element 21 ranges from 90 to 140 nm, for example, the thickness is 90 nm, 100 nm, 110 nm, 120 nm, 130 nm or 140 nm.

[0101] Optionally, combined Figure 7 In this embodiment, when the light-emitting element 21 includes a plurality of light-emitting units 23, the plurality of light-emitting units 23 include a first light-emitting unit 26 and a second light-emitting unit 27, wherein a refractive index of the hole transport layer 232 in the first light-emitting unit 26 is different from a refractive index of the hole transport layer 232 in the second light-emitting unit 27.

[0102] Furthermore, the thickness of the hole transport layer 232 in the first light-emitting unit 26 may be different from the thickness of the hole transport layer 232 in the second light-emitting unit 27 .

[0103] Furthermore, when the first electrode 22 is an anode, and the first electrode 22, the first light-emitting unit 26, and the second light-emitting unit 27 are stacked in sequence, the refractive index of the hole transport layer 232 in the first light-emitting unit 26 can also be set to be smaller than the refractive index of the hole transport layer 232 in the second light-emitting unit 27.

[0104] Furthermore, when the first electrode 22 is an anode, and the first electrode 22, the first light-emitting unit 26, and the second light-emitting unit 27 are stacked in sequence, the thickness of the hole transport layer 232 in the first light-emitting unit 26 can also be set to be smaller than the thickness of the hole transport layer 232 in the second light-emitting unit 27.

[0105] Optionally, in this embodiment, continue to refer to Figure 1 It is also possible to set the first light-emitting element 211 to include a first hole transport layer 2321, and the second light-emitting element 212 to include a second hole transport layer 2322, and the stacking order of the light-emitting units 23 where the first hole transport layer 2321 is located in the first light-emitting element 211 and the stacking order of the light-emitting units 23 where the second hole transport layer 2322 is located in the second light-emitting element 212 are the same, wherein the refractive index of the first hole transport layer 2321 is different from the refractive index of the second hole transport layer 2322.

[0106] Furthermore, the thickness of the first hole transport layer 2321 may be different from the thickness of the second hole transport layer 2322 .

[0107] The light emitting color of the first light emitting element 211 is different from the light emitting color of the second light emitting element 212. For example, the light emitting color of the first light emitting element 211 is red, and the light emitting color of the second light emitting element 212 is green, or the light emitting color of the first light emitting element 211 is green, and the light emitting color of the second light emitting element 212 is blue.

[0108] The present application also provides a display device, which includes the display panel in any of the above embodiments. The display device in the embodiments of the present invention can be any product or component with a display function, such as electronic paper, a mobile phone, a tablet computer, a television, a monitor, a laptop computer, a digital photo frame or a navigator.

[0109] The above description is only an implementation method of the present application, and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly used in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A display panel, characterized in that: include: substrate; A light-emitting layer, arranged on one side of the substrate, the light-emitting layer comprises a plurality of light-emitting elements, the light-emitting elements comprise a first electrode, at least one light-emitting unit and a second electrode stacked in sequence, each of the light-emitting units comprises a light-emitting material layer and a hole transport layer; Among them, the multiple light-emitting elements include a first light-emitting element and a second light-emitting element, the first light-emitting element includes a first hole transport layer, the second light-emitting element includes a second hole transport layer, the stacking order of the light-emitting units where the first hole transport layer is located in the first light-emitting element and the stacking order of the light-emitting units where the second hole transport layer is located in the second light-emitting element are the same, wherein the refractive index of the first hole transport layer is different from the refractive index of the second hole transport layer.

2. The display panel according to claim 1, characterized in that: The thickness of the first hole transport layer is different from the thickness of the second hole transport layer; Preferably, the light emitting color of the first light emitting element is different from the light emitting color of the second light emitting element.

3. The display panel according to claim 2, characterized in that: The plurality of light-emitting elements further include a third light-emitting element, the third light-emitting element includes a third hole transport layer, the stacking order of the light-emitting units where the third hole transport layer is located in the third light-emitting element, the stacking order of the light-emitting units where the first hole transport layer is located in the first light-emitting element, and the stacking order of the light-emitting units where the second hole transport layer is located in the second light-emitting element are the same, wherein the refractive index of the third hole transport layer is different from the refractive index of the first hole transport layer, and / or the refractive index of the third hole transport layer is different from the refractive index of the second hole transport layer; Preferably, the thickness of the third hole transport layer is different from the thickness of the first hole transport layer, and / or the thickness of the third hole transport layer is different from the thickness of the second hole transport layer; Preferably, the plurality of light-emitting elements are divided into a plurality of repeated pixel units, and the pixel unit includes the first light-emitting element, the second light-emitting element and the third light-emitting element; Preferably, the first light emitting element, the second light emitting element, and the third light emitting element emit different colors; Preferably, the light emitting colors of the first light emitting element, the second light emitting element and the third light emitting element are red, green and blue respectively.

4. The display panel according to claim 1, characterized in that: The first light-emitting element and the second light-emitting element each include one light-emitting unit, and the first light-emitting element and the second light-emitting element each have a first-order microcavity structure, wherein the refractive index of the hole transport layer in the first light-emitting element is less than the refractive index of the hole transport layer in the second light-emitting element; Preferably, the thickness of the hole transport layer in the first light-emitting element is smaller than the thickness of the hole transport layer in the second light-emitting element.

5. The display panel according to claim 1, characterized in that: The first light-emitting element and the second light-emitting element each include one light-emitting unit, and the first light-emitting element and the second light-emitting element each have a second-order microcavity structure, wherein the refractive index of the hole transport layer in the first light-emitting element is greater than the refractive index of the hole transport layer in the second light-emitting element; Preferably, the thickness of the hole transport layer in the first light-emitting element is smaller than the thickness of the hole transport layer in the second light-emitting element.

6. The display panel according to claim 1, characterized in that: The first light-emitting element and the second light-emitting element each include one light-emitting unit, the first light-emitting element has a first-order microcavity structure, and the second light-emitting element has a second-order microcavity structure, wherein the refractive index of the hole transport layer in the first light-emitting element is less than the refractive index of the hole transport layer in the second light-emitting element; Preferably, the refractive index of the hole transport layer in the first light-emitting element is in the range of 1.4 to 1.7; Preferably, the refractive index of the hole transport layer in the second light-emitting element is in the range of 1.8 to 2.

5.

7. The display panel according to claim 1, characterized in that: The first light-emitting element and the second light-emitting element each include one light-emitting unit, the first light-emitting element has a first-order microcavity structure, and the second light-emitting element has a second-order microcavity structure, wherein the thickness of the hole transport layer in the first light-emitting element is less than the thickness of the hole transport layer in the second light-emitting element; Preferably, the thickness of the hole transport layer in the first light-emitting element is in the range of 10 to 30 nm; Preferably, the thickness of the hole transport layer in the second light-emitting element is in the range of 90 to 140 nm; Preferably, the light emitting color of the second light emitting element is red, and the thickness of the hole transport layer in the second light emitting element is in the range of 90 to 140 nm; Preferably, the light emitting color of the second light emitting element is green, and the thickness of the hole transport layer in the second light emitting element is in the range of 100 to 130 nm; Preferably, the light emitting color of the second light emitting element is blue, and the thickness of the hole transport layer in the second light emitting element is in the range of 105 to 130 nm.

8. The display panel according to claim 1, characterized in that: The light-emitting element comprises one light-emitting unit, and the light-emitting element has a first-order microcavity structure, wherein the refractive index of the hole transport layer in the light-emitting element is in the range of 1.4 to 1.7; Preferably, the thickness of the hole transport layer in the light-emitting element is in the range of 10 to 30 nm.

9. The display panel according to claim 1, characterized in that: The light-emitting element comprises one light-emitting unit, and the light-emitting element has a second-order microcavity structure, wherein the refractive index of the hole transport layer in the light-emitting element is in the range of 1.8 to 2.5; Preferably, the thickness of the hole transport layer in the light-emitting element is in the range of 90 to 140 nm; Preferably, the luminescent color of the light-emitting element is red, and the thickness of the hole transport layer in the light-emitting element is in the range of 90 to 140 nm; Preferably, the luminescent color of the light-emitting element is green, and the thickness of the hole transport layer in the light-emitting element is in the range of 100 to 130 nm; Preferably, the light emitting element emits blue light, and the thickness of the hole transport layer in the light emitting element is in the range of 105 to 130 nm.

10. The display panel according to claim 1, characterized in that: The light-emitting element includes a plurality of light-emitting units, wherein the plurality of light-emitting units include a first light-emitting unit and a second light-emitting unit, wherein a refractive index of the hole transport layer in the first light-emitting unit is different from a refractive index of the hole transport layer in the second light-emitting unit; Preferably, the light emitting element comprises two light emitting units.

11. The display panel according to claim 10, characterized in that: The first electrode is an anode, and the first electrode, the first light-emitting unit, and the second light-emitting unit are stacked in sequence, wherein the refractive index of the hole transport layer in the first light-emitting unit is smaller than the refractive index of the hole transport layer in the second light-emitting unit; Preferably, the refractive index of the hole transport layer in the first light-emitting unit is in the range of 1.4 to 1.7; Preferably, the refractive index of the hole transport layer in the second light-emitting unit is in the range of 1.8 to 2.

5.

12. The display panel according to claim 10, characterized in that: The thickness of the hole transport layer in the first light-emitting unit is different from the thickness of the hole transport layer in the second light-emitting unit; Preferably, the first electrode is an anode, the first electrode, the first light-emitting unit, and the second light-emitting unit are stacked in sequence, and the thickness of the hole transport layer in the first light-emitting unit is less than the thickness of the hole transport layer in the second light-emitting unit; Preferably, the thickness of the hole transport layer in the first light-emitting unit is in the range of 10 to 30 nm; Preferably, the thickness of the hole transport layer in the second light-emitting unit is in the range of 25 to 75 nm; Preferably, the luminescent color of the light-emitting element is red, and the thickness of the hole transport layer in the second light-emitting unit of the light-emitting element is in the range of 25 to 75 nm; Preferably, the light emitting color of the light emitting element is green, and the thickness of the hole transport layer in the second light emitting unit of the light emitting element is in the range of 30 to 60 nm; Preferably, the light emitting color of the light emitting element is blue, and the thickness of the hole transport layer in the second light emitting unit of the light emitting element is in the range of 25 to 50 nm.

13. The display panel according to claim 1, characterized in that: The display panel further includes: An isolation structure, arranged on a side of the light-emitting layer away from the substrate, the isolation structure being provided with a plurality of isolation openings, the orthographic projections of the isolation openings on the substrate at least partially overlapping with the orthographic projections of the light-emitting elements on the substrate; Preferably, the isolation structure comprises a first end close to the substrate and a second end away from the substrate, and the orthographic projection of the first end on the substrate is located within the orthographic projection of the second end on the substrate; Preferably, the isolation structure is conductive, and the first electrode, the at least one light-emitting unit and the second electrode are stacked in sequence in a direction away from the substrate, wherein the second electrode extends to the side wall of the isolation structure and is electrically connected to the isolation structure.

14. A display panel, characterized in that: include: substrate; A light-emitting layer, arranged on one side of the substrate, the light-emitting layer comprises a plurality of light-emitting elements, the light-emitting elements comprise a first electrode, at least one light-emitting unit and a second electrode which are sequentially stacked, each of the light-emitting units comprises a light-emitting material layer and a hole transport layer; An isolation structure, arranged on a side of the light-emitting layer away from the substrate, the isolation structure being provided with a plurality of isolation openings, the orthographic projections of the isolation openings on the substrate at least partially overlapping with the orthographic projections of the light-emitting elements on the substrate; The plurality of light-emitting elements include a first light-emitting element and a second light-emitting element, and the refractive index of the hole transport layer in the first light-emitting element and the refractive index of the hole transport layer in the second light-emitting element are different.

15. The display panel according to claim 14, characterized in that: The thickness of the hole transport layer in the first light-emitting element and the thickness of the hole transport layer in the second light-emitting element are different.

16. The display panel according to claim 14, characterized in that: The first light-emitting element includes a first hole transport layer, the second light-emitting element includes a second hole transport layer, the stacking order of the light-emitting units where the first hole transport layer is located in the first light-emitting element and the stacking order of the light-emitting units where the second hole transport layer is located in the second light-emitting element are the same, wherein the refractive index of the first hole transport layer is different from the refractive index of the second hole transport layer; Preferably, the thickness of the first hole transport layer is different from the thickness of the second hole transport layer; Preferably, the light emitting color of the first light emitting element is different from the light emitting color of the second light emitting element.

17. The display panel according to claim 14, characterized in that: The light-emitting element comprises one light-emitting unit, and the light-emitting element has a first-order microcavity structure, wherein the refractive index of the hole transport layer in the light-emitting element is in the range of 1.4 to 1.7; Preferably, the thickness of the hole transport layer in the light-emitting element is in the range of 10 to 30 nm.

18. The display panel according to claim 14, characterized in that: The light-emitting element comprises one light-emitting unit, and the light-emitting element has a second-order microcavity structure, wherein the refractive index of the hole transport layer in the light-emitting element is in the range of 1.8 to 2.5; Preferably, the thickness of the hole transport layer in the light-emitting element is in the range of 90 to 140 nm.

19. The display panel according to claim 14, characterized in that: The light-emitting element includes a plurality of light-emitting units, wherein the plurality of light-emitting units include a first light-emitting unit and a second light-emitting unit, wherein a refractive index of the hole transport layer in the first light-emitting unit is different from a refractive index of the hole transport layer in the second light-emitting unit; Preferably, the thickness of the hole transport layer in the first light-emitting unit is different from the thickness of the hole transport layer in the second light-emitting unit; Preferably, the first electrode is an anode, and the first electrode, the first light-emitting unit, and the second light-emitting unit are stacked in sequence, wherein the refractive index of the hole transport layer in the first light-emitting unit is smaller than the refractive index of the hole transport layer in the second light-emitting unit; Preferably, the first electrode is an anode, the first electrode, the first light-emitting unit, and the second light-emitting unit are stacked in sequence, and the thickness of the hole transport layer in the first light-emitting unit is smaller than the thickness of the hole transport layer in the second light-emitting unit.

20. A display device, characterized in that: Comprising the display panel as claimed in any one of claims 1 to 19.

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