Light emitting diode, display substrate and display device

Abstract

Provided is a light emitting diode including: a first electrode; a light-emitting functional layer on the first electrode; the second electrode is located on the side, away from the first electrode, of the light-emitting functional layer, and the first electrode comprises a first reflection metal layer and a surface electrode layer located between the first reflection metal layer and the light-emitting functional layer; the surface, facing the surface electrode layer, of the first reflection metal layer is provided with a plurality of protrusion structures arranged at intervals, and the protrusion structures protrude towards the side close to the second electrode.

Description

Technical Field

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

[0002] Organic Light-Emitting Diode (OLED) display technology has the advantages of being light, thin, low power, high contrast, and flexible display, so OLED display technology is considered to be the most promising new generation display technology. In OLED display technology, multiple OLED devices emit light independently to display the desired image. How to improve the light output efficiency of OLED devices is one of the topics that display product developers are concerned about.

[0003] The above information disclosed in this section is only for understanding the background of the inventive concept of the present disclosure and therefore the above information may contain information that does not constitute the prior art. Summary of the invention

[0004] In one aspect, a light emitting diode is provided, comprising:

[0005] a first electrode;

[0006] a light-emitting functional layer, located on the first electrode; and

[0007] a second electrode, located on a side of the light-emitting functional layer away from the first electrode,

[0008] Wherein, the first electrode comprises a first reflective metal layer and a surface electrode layer located between the first reflective metal layer and the light-emitting functional layer; and

[0009] A surface of the first reflective metal layer facing the surface electrode layer has a plurality of convex structures arranged at intervals, and the convex structures protrude toward a side close to the second electrode.

[0010] According to some exemplary embodiments, the edge profile of the protruding structure is rounded.

[0011] According to some exemplary embodiments, a diameter of the protruding structure is greater than a distance between adjacent protruding structures.

[0012] According to some exemplary embodiments, the diameter of the protrusion structure is 300 nm-500 nm, and / or the distance between adjacent protrusion structures is 300 nm-380 nm.

[0013] According to some exemplary embodiments, the protrusion structure includes an annular protrusion.

[0014] According to some exemplary embodiments, the surface of the first reflective metal layer close to the surface electrode layer has a first recessed portion and a second recessed portion, the first recessed portion is located inside the annular protrusion, and the second recessed portion is located between adjacent annular protrusions; and

[0015] Along the light emitting direction of the light emitting diode, the depression depth of the first depression portion is greater than the depression depth of the second depression portion.

[0016] According to some exemplary embodiments, the plurality of annular protrusions include a plurality of first annular protrusions and a plurality of second annular protrusions, the plurality of first annular protrusions are arranged at intervals along the edge of the first reflective metal layer to form a circle of annular protrusions, and the plurality of first annular protrusions are arranged around the outside of the plurality of second annular protrusions; and

[0017] The first reflective metal layer also includes a connecting wire, which is annular and arranged around multiple first annular protrusions. The connecting wire is respectively connected to the multiple first annular protrusions to form an integrated structure, and the surface of the connecting wire close to the surface electrode layer is flush with the surface of the first annular protrusion close to the surface electrode layer.

[0018] According to some exemplary embodiments, the protrusion structure includes a pancake-shaped protrusion.

[0019] According to some exemplary embodiments, the first electrode further includes a spacer electrode layer located on a side of the first reflective metal layer close to the light-emitting functional layer, and a second reflective metal layer located between the spacer electrode layer and the surface electrode layer; and

[0020] The second reflective metal layer includes a plurality of reflective metal portions that are spaced apart from each other, and the surface electrode layer is in contact with the spaced electrode layer through gaps between adjacent reflective metal portions.

[0021] According to some exemplary embodiments, an edge profile of the reflective metal portion is rounded.

[0022] According to some exemplary embodiments, the orthographic projections of the plurality of reflective metal parts on the virtual plane partially overlap with the orthographic projections of the plurality of pancake-shaped protrusions on the virtual plane, and the virtual plane is perpendicular to the light emitting direction of the light emitting diode; or,

[0023] The orthographic projections of the plurality of reflective metal parts on the virtual plane respectively coincide with the orthographic projections of the plurality of circular pancake-shaped protrusions on the virtual plane.

[0024] According to some exemplary embodiments, along the light emitting direction of the light emitting diode, the thickness of the second reflective metal layer is less than the thickness of the first reflective metal layer.

[0025] In another aspect, a display substrate is provided, comprising a plurality of light emitting devices, at least one of the light emitting devices comprising a light emitting diode as described in any one of the above items.

[0026] According to some exemplary embodiments, the plurality of light emitting devices include a red light emitting device, a green light emitting device, and a blue light emitting device, and the blue light emitting device includes the light emitting diode.

[0027] In another aspect, a display device is provided, comprising the display substrate as described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Other objects and advantages of the present disclosure will be apparent from the following description of the present disclosure with reference to the accompanying drawings, and will help to have a comprehensive understanding of the present disclosure.

[0029] Figure 1 A cross-sectional view of a light emitting diode according to some embodiments of the present disclosure is schematically shown.

[0030] Figure 2 A cross-sectional view of a first electrode of a light emitting diode according to some embodiments of the present disclosure is schematically shown.

[0031] Figure 3 A plan view schematically shows a first electrode of a light emitting diode according to some embodiments of the present disclosure.

[0032] Figure 4 A cross-sectional view of a first electrode of a light emitting diode according to some embodiments of the present disclosure is schematically shown.

[0033] Figure 5 A plan view schematically shows a first electrode of a light emitting diode according to some embodiments of the present disclosure.

[0034] Figure 6 A cross-sectional view of a first electrode of a light emitting diode according to some embodiments of the present disclosure is schematically shown.

[0035] Figure 7 A plan view schematically illustrates a first reflective metal layer of a first electrode of a light emitting diode according to some embodiments of the present disclosure.

[0036] Figure 8 A plan view schematically illustrates a second reflective metal layer of a first electrode of a light emitting diode according to some embodiments of the present disclosure.

[0037] Fig. 9 A cross-sectional view of a first electrode of a light emitting diode according to some embodiments of the present disclosure is schematically shown.

[0038] Fig.10 Schematically showing the reflectivity test spectrum of the first electrode according to some embodiments of the present disclosure

[0039] Fig.11 A cross-sectional view of a display substrate according to some embodiments of the present disclosure is schematically shown.

[0040] It should be noted that, for the sake of clarity, in the drawings used to describe the embodiments of the present disclosure, the sizes of layers, structures or regions may be enlarged or reduced, that is, these drawings are not drawn according to the actual scale. DETAILED DESCRIPTION

[0041] In the following description, for the purpose of explanation, many specific details are set forth to provide a comprehensive understanding of various exemplary embodiments. However, it is apparent that various exemplary embodiments may be implemented without these specific details or with one or more equivalent arrangements. In other cases, well-known structures and devices are shown in block diagram form to avoid making various exemplary embodiments unnecessarily obscure. In addition, various exemplary embodiments may be different, but not necessarily exclusive. For example, the specific shape, configuration, and characteristics of an exemplary embodiment may be used or implemented in another exemplary embodiment without departing from the inventive concept.

[0042] In the accompanying drawings, the size and relative size of the elements may be exaggerated for the purpose of clarity and / or description. Thus, the size and relative size of the individual elements are not necessarily limited to the size and relative size shown in the drawings. When the exemplary embodiments may be implemented differently, the specific process sequence may be performed differently from the described sequence. For example, two processes described in succession may be performed substantially simultaneously or in an order opposite to the described sequence. In addition, the same reference numerals represent the same elements.

[0043] When an element is described as "on" another element, "connected to" another element or "coupled to" another element, the element may be directly on another element, directly connected to another element or directly coupled to another element, or there may be an intermediate element. However, when an element is described as "directly on" another element, "directly connected to" another element or "directly coupled to" another element, there is no intermediate element. Other terms and / or expressions used to describe the relationship between elements should be interpreted in a similar manner, for example, "between..." versus "directly between...", "adjacent" versus "directly adjacent" or "on..." versus "directly on...", etc. In addition, the term "connection" may refer to physical connection, electrical connection, communication connection and / or fluid connection. In addition, the X-axis, Y-axis and Z-axis are not limited to the three axes of the rectangular coordinate system, and can be interpreted in a broader sense. For example, the X-axis, Y-axis and Z-axis may be perpendicular to each other, or may represent different directions that are not perpendicular to each other. For the purpose of this disclosure, "at least one of X, Y, and Z" and "at least one selected from the group consisting of X, Y, and Z" may be interpreted as only X, only Y, only Z, or any combination of two or more of X, Y, and Z such as XYZ, XY, YZ, and XZ. As used herein, the term "and / or" includes any and all combinations of one or more of the listed associated items.

[0044] It should be understood that, although the terms first, second, etc. may be used herein to describe different elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. For example, without departing from the scope of the exemplary embodiment, a first element may be named a second element, and similarly, a second element may be named a first element.

[0045] Figure 1 A cross-sectional view of a light emitting diode according to some embodiments of the present disclosure is schematically shown. Figure 2 Schematically shows a cross-sectional view of a first electrode of a light emitting diode according to some embodiments of the present disclosure, Figure 3 A plan view of a first electrode of a light emitting diode according to some embodiments of the present disclosure is schematically shown, wherein: Figure 2 Schematically shows the Figure 3 Cross-sectional view taken along the midline AA'.

[0046] Reference Figure 1 The light emitting diode 100 may include a first electrode 110 , a light emitting functional layer 120 located on the first electrode 110 , and a second electrode 130 located on a side of the light emitting functional layer 120 away from the first electrode 110 .

[0047] The light-emitting functional layer 120 includes a first functional layer 121 located on the first electrode 110 , a light-emitting layer 122 located on a side of the first functional layer 121 away from the first electrode 110 , and a second functional layer 123 located between the light-emitting layer 122 and the second electrode 130 .

[0048] For example, the first electrode 110 may be an anode, and the second electrode 130 may be a cathode. The first functional layer 121 may include a hole injection layer on the first electrode 110 and a hole transport layer between the hole injection layer and the light-emitting layer 122. The second functional layer 123 may include an electron transport layer on the light-emitting layer 122 and an electron injection layer between the electron transport layer and the second electrode 130. Of course, the first functional layer 121 and the second functional layer 123 may also include other functional layers, such as a hole blocking layer, an electron blocking layer, etc., as required.

[0049] For example, the light emitting layer 122 may include an organic light emitting material, and the light emitting diode 100 may be an OLED device.

[0050] Combined with reference Figure 1 and Figure 2 The first electrode 110 includes a first reflective metal layer 112 and a surface electrode layer 113 located between the first reflective metal layer 112 and the light-emitting functional layer 120. The first reflective metal layer 112 has a high reflectivity. The first electrode 110 serves as a reflective electrode, so that the light-emitting diode 100 emits light in a top emission mode.

[0051] For example, the material of the first reflective metal layer 112 includes a metal material with a relatively high reflectivity. Schematically, the material of the first reflective metal layer 112 includes silver or aluminum.

[0052] For example, the material of the surface electrode layer 113 includes indium tin oxide.

[0053] For example, the thickness of the second electrode 130 is relatively thin, so that the second electrode 130 has a relatively high light transmittance. The material of the second electrode 130 may include magnesium and silver.

[0054] For example, the first electrode 110 may further include a bottom electrode layer 111 located on a side of the first reflective metal layer 112 away from the surface electrode layer 113 , and the material of the bottom electrode layer 111 includes indium tin oxide. The material of the bottom electrode layer 111 may be consistent with that of the surface electrode layer 113 .

[0055] It should be noted that in Figure 3 In the illustrated planar structure, the edge profile of the first reflective metal layer 112 is roughly a rounded square. As required, the edge shape of the first reflective metal layer 112, that is, the shape of the light emitting diode 100, can also be a rounded rectangle, circle, ellipse or hexagon.

[0056] Combined with reference Figure 1-Figure 3 The surface of the first reflective metal layer 112 facing the surface electrode layer 113 has a plurality of convex structures 200 arranged at intervals, and the convex structures 200 protrude toward the side close to the second electrode 130. By providing the convex structures 200 on the surface of the first reflective metal layer 112, the light extraction efficiency of the light emitting diode 100 can be effectively improved.

[0057] The inventors have found that, currently, in OLED devices, the energy released in the form of radiated light accounts for about 30% of the total energy generated by excitons. Among the energy lost in the form of non-luminescence, a large part of the energy is lost in the form of surface plasmon effects (SPPs) on the surfaces of the cathode and anode, and this part of the energy accounts for up to 20%, which has a great impact on the light extraction efficiency of the light emitting diode 100.

[0058] In the light emitting diode 100 of the embodiment of the present disclosure, by providing a protruding structure 200 on the surface of the first reflective metal layer 112 , the energy loss caused by the SPPs effect in the first electrode 110 can be reduced, thereby improving the light extraction efficiency of the light emitting diode 100 .

[0059] It should be noted that in Figure 2 In the schematic cross-sectional structure, the first reflective metal layer 112 is filled with dots as a whole, but Figure 3 In the schematic planar structure, in order to more clearly illustrate the structure of the protruding structure 200 , only the protruding structure 200 in the first reflective metal layer 112 is filled in a dotted manner. Figure 2 The first reflective metal layer 112 is shown Figure 3 The structures of the illustrated first reflective metal layers 112 are substantially the same.

[0060] According to some exemplary embodiments, in combination with reference Figure 1-Figure 3 The edge contour of the protrusion structure 200 is circular (i.e., the edge of the orthographic projection of the protrusion structure 200 on a virtual plane perpendicular to the light emitting direction X is circular), so that the protrusion structure 200 is symmetrically distributed in all directions. Such a configuration is conducive to further reducing the energy loss caused by the SPPs effect in the first electrode 110, thereby improving the light extraction efficiency of the light emitting diode 100.

[0061] According to some exemplary embodiments, in combination with reference Figure 1-Figure 3 , the diameter of the protruding structure 200 is greater than the spacing G between adjacent protrusion structures 200 . Such a configuration is beneficial to further reduce the energy loss caused by the SPPs effect in the first electrode 110 , thereby improving the light extraction efficiency of the light emitting diode 100 .

[0062] According to some exemplary embodiments, in combination with reference Figure 2 and Figure 3 , the diameter of the protruding structure 200 It is 300nm-500nm.

[0063] For example, the diameter of the protrusion structure 200 It can be 300nm, 320nm, 340nm, 360nm, 380nm, 400nm, 320nm, 320nm, 320nm, 320nm, 320nm or 320nm, etc.

[0064] According to some exemplary embodiments, in combination with reference Figure 2 and Figure 3 The spacing G between adjacent protrusion structures 200 is 300nm-380nm to avoid unstable interference in the visible light band.

[0065] For example, the interval G between adjacent protrusion structures 200 may be 300 nm, 310 nm, 320 nm, 330 nm, 340 nm, 350 nm, 360 nm, 370 nm, or 380 nm.

[0066] It should be noted that the interval G between adjacent protrusion structures 200 should be understood as the interval in the direction from the center of one protrusion structure 200 to the center of another protrusion structure 200 .

[0067] According to some exemplary embodiments, the plurality of protrusion structures 200 may be arranged at equal intervals or at non-equal intervals, but it is necessary to ensure that the interval G of each protrusion structure 200 is within the range of 300 nm-380 nm.

[0068] According to some exemplary embodiments, the diameter of the plurality of protrusion structures 200 is can be equal to each other, or the diameter of at least one protrusion structure 200 and the diameter of at least one other protruding structure 200 Not equal, but the diameter of each protrusion structure 200 needs to be ensured All are in the range of 300nm-500nm.

[0069] According to some exemplary embodiments, in combination with reference Figure 1-Figure 3 The protrusion structure 200 includes a ring-shaped protrusion 210 . The protrusion structure 200 is configured to be ring-shaped, which is beneficial to further reduce the energy loss caused by the SPPs effect in the first electrode 110 , thereby improving the light extraction efficiency of the light emitting diode 100 .

[0070] According to some exemplary embodiments, in combination with reference Figure 1-Figure 3 The surface of the first reflective metal layer 112 close to the surface electrode layer 113 has a first recessed portion A1 and a second recessed portion A2. The first recessed portion A1 is located inside the annular protrusion 210, and the second recessed portion A2 is located between adjacent annular protrusions 210. The second recessed portions A2 located between each annular protrusion 210 are connected in a grid shape.

[0071] The first recessed portion A1 has a recessed depth D1 greater than the second recessed portion A2 in the light emitting direction X. This configuration is beneficial for further reducing energy loss caused by the SPPs effect in the first electrode 110 , thereby improving the light emitting efficiency of the light emitting diode 100 .

[0072] It should be noted that the first electrode 110 of the light emitting diode 100 is a reflective electrode, the light emitting diode 100 is a top emitting device, and the light emitting direction X should be understood as the direction from the first electrode 110 to the second electrode 130 .

[0073] According to some exemplary embodiments, referring to Figure 3 The depression depth D1 of the first depression A1 is 10nm-30nm.

[0074] For example, the recess depth D1 of the first recess A1 may be 10 nm, 12 nm, 14 nm, 16 nm, 18 nm, 20 nm, 22 nm, 24 nm, 26 nm, 28 nm, or 30 nm.

[0075] According to some exemplary embodiments, referring to Figure 3 , the depression depth D2 of the second depression A2 is 3-5 nm.

[0076] For example, the depression depth D2 of the second depression A2 may be 3 nm, 3.5 nm, 4 nm, 4.5 nm, or 5 nm.

[0077] According to some exemplary embodiments, referring to Figure 3 The edge profile of the first recessed portion A1 includes a circle, and the diameter of the first recessed portion A1 is The distance G between adjacent annular protrusions 210 may be consistent.

[0078] Figure 4 Schematically shows a cross-sectional view of a first electrode of a light emitting diode according to some embodiments of the present disclosure, Figure 5 A plan view of a first electrode of a light emitting diode according to some embodiments of the present disclosure is schematically shown, wherein: Figure 4 Schematically shows the Figure 5 Cross-section taken along the midline BB'.

[0079] According to some exemplary embodiments, in combination with reference Figure 4 and Figure 5 The plurality of annular protrusions 210 include a plurality of first annular protrusions 211 and a plurality of second annular protrusions 212. The plurality of first annular protrusions 211 are arranged at intervals along the edge of the first reflective metal layer 112 to form a circle of annular protrusions 210, and the plurality of first annular protrusions 211 are arranged around the outside of the plurality of second annular protrusions 212. That is, the annular protrusions 210 located in the outermost circle are the first annular protrusions 211, and the annular protrusions 210 located in the inner side are the second annular protrusions 212.

[0080] The first reflective metal layer 112 further includes a connecting wire 112L, which is annular and arranged around a plurality of first annular protrusions 211. The connecting wire 112L and the plurality of first annular protrusions 211 are respectively connected to form an integral structure, and a surface of the connecting wire 112L close to the surface electrode layer 113 is flush with a surface of the first annular protrusion 211 close to the surface electrode layer 113. By providing the annular connecting wire 112L, the plurality of first annular protrusions 211 located in the outermost circle are sequentially connected, which can avoid local current concentration, thereby facilitating improvement of brightness uniformity of the light emitting diode 100 within the light emitting surface.

[0081] It should be noted that in Figure 4 In the schematic cross-sectional structure, the first reflective metal layer 112 is filled with dots as a whole, but Figure 5 In the schematic planar structure, in order to more clearly illustrate the structures of the annular protrusion 210 and the connecting wiring 112L, only the structures of the annular protrusion 210 and the connecting wiring 112L in the first reflective metal layer 112 are dot-filled. Figure 4 The first reflective metal layer 112 is shown Figure 5 The structures of the illustrated first reflective metal layers 112 are substantially the same.

[0082] It should be noted that the "integrated structure" in the embodiments of the present disclosure refers to a structure in which two (or more) structures are formed by the same deposition process and patterned by the same composition process to form a structure connected to each other, and their materials may be the same or different.

[0083] It should be noted that there is no significant difference between the structures of the first annular protrusion 211 and the second annular protrusion 212, and the specific structures and setting parameters of the first annular protrusion 211 and the second annular protrusion 212 can refer to the above description. Here, only the distribution positions of the different annular protrusions 210 are divided into the first annular protrusion 211 and the second annular protrusion 212, so that the setting method of the connection line 112L can be more clearly explained.

[0084] in addition, Figure 5In the figure, only a plurality of first annular protrusions 211 and a plurality of second annular protrusions 212 are schematically shown. In an actual structure, the specific number of the first annular protrusions 211 and the second annular protrusions 212 may be more specific. Figure 5 The examples shown are more or less, and the embodiments of the present disclosure are not limited to this.

[0085] Figure 6 A cross-sectional view of a first electrode of a light emitting diode according to some embodiments of the present disclosure is schematically shown. Figure 7 A plan view schematically illustrates a first reflective metal layer of a first electrode of a light emitting diode according to some embodiments of the present disclosure. Figure 8 A plan view schematically illustrates a second reflective metal layer of a first electrode of a light emitting diode according to some embodiments of the present disclosure.

[0086] According to some exemplary embodiments, in combination with reference Figure 6 and Figure 7 The protrusion structure 200 includes a disc-shaped protrusion 220 .

[0087] It should be noted that the structure of the disc-shaped protrusion 220 should be understood as follows: the orthographic projection of the disc-shaped protrusion 220 on a virtual plane perpendicular to the light-emitting direction X is a circle, and the diameter of the circle is greater than the thickness of the disc-shaped protrusion 220 along the light-emitting direction X.

[0088] According to some exemplary embodiments, in combination with reference Figure 6 , Figure 7 and Figure 8 The first electrode 110 further includes a spacer electrode layer 114 located on the side of the first reflective metal layer 112 close to the light-emitting functional layer 120, and a second reflective metal layer 115 located between the spacer electrode layer 114 and the surface electrode layer 113. The second reflective metal layer 115 includes a plurality of reflective metal portions 1151 arranged at intervals, and the surface electrode layer 113 contacts the spacer electrode layer 114 through the gaps between adjacent reflective metal portions 1151. By arranging the second reflective metal layer 115 on the side of the first reflective metal layer 112 close to the surface electrode layer 113, it is beneficial to further reduce the energy loss caused by the SPPs effect in the first electrode 110, thereby improving the light extraction efficiency of the light-emitting diode 100.

[0089] For example, the material of the second reflective metal layer 115 includes a metal material with high reflectivity. Schematically, the material of the first reflective metal layer 112 includes silver or aluminum, etc. The material of the second reflective metal layer 115 can be consistent with the material of the first reflective metal layer 112 .

[0090] For example, the material of the spacer electrode layer 114 includes indium tin oxide. The material of the spacer electrode layer 114 can be consistent with the material of the surface electrode layer 113 .

[0091] According to some exemplary embodiments, the edge profile of the reflective metal portion 1151 is circular, that is, the shape of the reflective metal portion 1151 may be kept consistent with the distance from the pancake-shaped protrusion 220 .

[0092] According to some exemplary embodiments, in combination with reference Figure 6 , Figure 7 and Figure 8 , the multiple reflective metal parts 1151 and the multiple pancake-shaped protrusions 220 may be arranged alternately, and the orthographic projections of the multiple reflective metal parts 1151 on the virtual plane partially overlap with the orthographic projections of the multiple pancake-shaped protrusions 220 on the virtual plane, and the virtual plane is perpendicular to the light emitting direction X. In other words, the orthographic projections of the interval parts of the reflective metal parts 1151 on the virtual plane overlap with the orthographic projections of the pancake-shaped protrusions 220 on the virtual plane.

[0093] It should be noted that in Figure 7 In the schematic planar structure, only a plurality of pancake-shaped protrusions 220 are schematically shown. In an actual light-emitting diode, the number of pancake-shaped protrusions 220 may be greater than 1. Figure 7 more or less than indicated. Figure 8 In the schematic planar structure, only a plurality of reflective metal parts 1151 are schematically shown. In an actual light emitting diode, the number of reflective metal parts 1151 may be greater than 1. Figure 8 In addition, the overlapping manner of the reflective metal portion 1151 and the disc-shaped protrusion 220 is not limited in the embodiment of the present disclosure and can be adjusted according to actual needs.

[0094] Fig. 9 A cross-sectional view of a first electrode of a light emitting diode according to some embodiments of the present disclosure is schematically shown.

[0095] According to some exemplary embodiments, referring to Fig. 9 , the plurality of reflective metal parts 1151 and the plurality of pancake-shaped protrusions 220 may be arranged in an aligned manner up and down, and the orthographic projections of the plurality of reflective metal parts 1151 on the virtual plane respectively coincide with the orthographic projections of the plurality of pancake-shaped protrusions 220 on the virtual plane. In other words, the spacing between adjacent reflective metal parts 1151 is equal to the spacing between adjacent pancake-shaped protrusions 220, and the shape of the orthographic projection of the reflective metal part 1151 on the virtual plane is the same as the shape of the orthographic projection of the pancake-shaped protrusion 220 on the virtual plane.

[0096] According to some exemplary embodiments, referring to Figure 6 , along the light emitting direction X, the thickness THK2 of the second reflective metal layer 115 is less than the thickness THK1 of the first reflective metal layer 112 .

[0097] It should be noted that the thickness THK1 of the first reflective metal layer 112 should be understood as the thickness where the protruding structure 200 is provided.

[0098] For example, the thickness THK2 of the second reflective metal layer 115 may be 10 nm to 20 nm. Schematically, the thickness THK2 of the second reflective metal layer 115 may be 10 nm, 11 nm, 12 nm, 13 nm, 14 nm, 15 nm, 16 nm, 17 nm, 18 nm, 19 nm or 20 nm.

[0099] According to some exemplary embodiments, referring to Figure 6 Along the light emitting direction X, the thickness THK2 of the second reflective metal layer 115 is greater than or equal to the protruding height H of the circular pancake-shaped protrusion 220 .

[0100] According to some exemplary embodiments, referring to Figure 6 , the protrusion height H of the disc-shaped protrusion 220 is 3-10nm.

[0101] For example, the protrusion height H of the pancake-shaped protrusion 220 may be 3 nm, 4 nm, 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, or 10 nm.

[0102] According to some exemplary embodiments, referring to Figure 6 , the thickness THK3 of the spacing electrode layer 114 is 5 nm to 15 nm. Schematically, the thickness THK3 of the spacing electrode layer 114 can be 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, 11 nm, 12 nm, 13 nm, 14 nm or 15 nm, etc.

[0103] It should be noted that the thickness THK3 of the spacer electrode layer 114 should be understood as the thickness of the film layer located above the disc-shaped protrusion 220 .

[0104] The following is described in conjunction with more specific embodiments:

[0105] Provide a first electrode①, whose cross-sectional structure refers to Figure 6, including a first reflective metal layer 112, a spacing electrode layer 114, a second reflective metal layer 115 and a surface electrode layer 113. The material of the first reflective metal layer 112 is silver, the thickness of the first reflective metal layer 112 is 100nm, the protrusion height of the disc-shaped protrusion 220 in the first reflective metal layer 112 is 10nm, the diameter of the disc-shaped protrusion 220 is 400nm, and the spacing between the disc-shaped protrusions 220 is 300nm. The material of the spacing electrode layer 114 is indium tin oxide, and the thickness of the spacing electrode layer 114 is 5nm. The material of the second reflective metal layer 115 is silver, the thickness of the second reflective metal layer 115 is 10nm, the diameter of the reflective metal part 1151 is 400nm, the spacing between the reflective metal parts 1151 is 300nm, and the reflective metal parts 1151 and the disc-shaped protrusions 220 are arranged alternately. The material of the surface electrode layer 113 is indium tin oxide, and the thickness of the surface electrode layer 113 is 7nm.

[0106] The first electrode ① is illuminated from the side of the surface electrode layer 113 using blue light (wavelength is 400-480nm), and the distribution of the electric field intensity in the first electrode ① caused by the light is measured. It is found that there is a certain electric field intensity in both the first reflective metal layer 112 and the second reflective metal layer 115, and the electric field intensity at the edge of the pancake-shaped protrusion 220 and the edge of the reflective metal part 1151 is significantly reduced. After analysis, the non-uniform electric field distribution is caused by the specific structural design in the first electrode ①, which cuts off the SPPs effect on the electrode surface. It can be explained that the specific structural design in the first electrode ① can cut off the SPPs effect on the surface of the first electrode, which is beneficial to reduce the energy loss caused by the SPPs effect and improve the light extraction efficiency of the light-emitting diode.

[0107] A first electrode ② is provided, which includes a first reflective metal layer 112 and a surface electrode layer 113. The material of the first reflective metal layer 112 is silver, and the thickness of the first reflective metal layer 112 is 100nm. The material of the surface electrode layer 113 is indium tin oxide, and the thickness of the surface electrode layer 113 is 7nm.

[0108] The reflectivity test was performed on the first electrode ① and the first electrode ② respectively. Fig.10 The reflectivity test spectrum of the first electrode according to some embodiments of the present disclosure is schematically shown. Fig.10 It can be seen that in the blue light band of 400nm-480nm, the reflectivity of the first electrode ① is significantly higher than that of the first electrode ②, which is about 10% higher. This shows that the specific structural design of the first electrode ① can cut off the SPPs effect on the surface of the first electrode, reduce the energy loss caused by the SPPs effect on the surface of the first electrode, and make more light re-emitted after reflection, which is beneficial to improve the light extraction efficiency of the light-emitting diode.

[0109] Fig.11 A cross-sectional view of a display substrate according to some embodiments of the present disclosure is schematically shown.

[0110] Reference Fig.11 The display substrate 10 includes a driving substrate 300 and a plurality of light emitting devices 400, wherein the plurality of light emitting devices 400 are spaced apart and electrically connected to the driving substrate 300. At least one light emitting device 400 includes the aforementioned light emitting diode 100. The driving substrate 300 may include a base substrate 310 and a driving circuit layer 320 located on the base substrate 310, and the plurality of light emitting devices 400 are electrically connected to the driving circuit layer 320.

[0111] According to some exemplary embodiments, referring to Fig.10 The plurality of light emitting devices 400 include a red light emitting device 410, a green light emitting device 420 and a blue light emitting device 430, and the blue light emitting device 430 includes the light emitting diode 100 described above.

[0112] The inventor has found through research that among the red light-emitting device 410, the green light-emitting device 420 and the blue light-emitting device 430, the microcavity length of the blue light-emitting device 430 is shorter, and the blue light wavelength is shorter and the energy is stronger. These two factors will cause the energy loss problem of the blue light-emitting device 430 due to the SPPs effect to be more serious. Therefore, the blue light-emitting device 430 can be set to have the structure of the light-emitting diode 100 described above, so as to improve the light extraction efficiency of the blue light-emitting device 400.

[0113] Of course, according to actual needs, the red light emitting device 410 and / or the green light emitting device 420 may also be configured to have the structure of the light emitting diode 100 described above.

[0114] It should be noted that when the light emitting diode 100 described above is applied to a red light emitting device 410, a green light emitting device 420, and a blue light emitting device 430, the structures of the light emitting devices 400 of different colors (specifically, the structure of the first electrode 110) can remain the same, but the size of the microstructure on the first electrode 110 needs to be set differently. In the light emitting diode 100 described above, the size of the microstructure is set based on the situation that the light emitting diode 100 emits blue light.

[0115] At least some embodiments of the present disclosure also provide a display device, which includes a display substrate as described above. The display device may include any device or product having a display function. For example, the display device may be a smart phone, a mobile phone, an e-book reader, a desktop computer (PC), a laptop PC, a netbook PC, a personal digital assistant (PDA), a portable multimedia player (PMP), a digital audio player, a mobile medical device, a camera, a wearable device (such as a head-mounted device, an electronic clothing, an electronic bracelet, an electronic necklace, an electronic accessory, an electronic tattoo, or a smart watch), a television, etc.

[0116] It should be understood that the display device according to some exemplary embodiments of the present disclosure has all the features and advantages of the above-mentioned display substrate, and these features and advantages can be referred to the above description of the display substrate, which will not be repeated here.

[0117] As used herein, the terms "substantially," "approximately," "approximately," and other similar terms are used as terms of approximation rather than as terms of degree, and they are intended to account for the inherent deviations in measured or calculated values ​​that would be recognized by one of ordinary skill in the art. Taking into account factors such as process fluctuations, measurement problems, and errors associated with the measurement of a particular quantity (i.e., limitations of the measurement system), "approximately" or "approximately" as used herein include the stated value and mean that the particular value is within an acceptable range of deviation as determined by one of ordinary skill in the art. For example, "approximately" can mean within one or more standard deviations, or within ±10% or ±5% of the stated value.

[0118] Although some embodiments according to the general inventive concept of the present disclosure have been illustrated and described, it will be appreciated by those skilled in the art that changes may be made to these embodiments without departing from the principles and spirit of the general inventive concept of the present disclosure, the scope of which is defined by the claims and their equivalents.

Claims

1. A light emitting diode, wherein: The light emitting diode comprises: a first electrode; a light-emitting functional layer, located on the first electrode; and a second electrode, located on a side of the light-emitting functional layer away from the first electrode, Wherein, the first electrode comprises a first reflective metal layer and a surface electrode layer located between the first reflective metal layer and the light-emitting functional layer; and A surface of the first reflective metal layer facing the surface electrode layer has a plurality of convex structures arranged at intervals, and the convex structures protrude toward a side close to the second electrode.

2. The light emitting diode according to claim 1, wherein: The edge profile of the protruding structure is circular.

3. The light emitting diode according to claim 2, wherein: The diameter of the protruding structure is greater than the interval between adjacent protruding structures.

4. The light emitting diode according to claim 3, wherein: The diameter of the protrusion structure is 300nm-500nm, and / or the interval between adjacent protrusion structures is 300nm-380nm.

5. The light emitting diode according to any one of claims 2 to 4, wherein: The protrusion structure includes an annular protrusion.

6. The light emitting diode according to claim 5, wherein: The surface of the first reflective metal layer close to the surface electrode layer has a first recessed portion and a second recessed portion, the first recessed portion is located inside the annular protrusion, and the second recessed portion is located between adjacent annular protrusions; as well as Along the light emitting direction of the light emitting diode, the depression depth of the first depression portion is greater than the depression depth of the second depression portion.

7. The light emitting diode according to claim 5 or 6, wherein: The plurality of annular protrusions include a plurality of first annular protrusions and a plurality of second annular protrusions, the plurality of first annular protrusions are arranged at intervals along the edge of the first reflective metal layer to form a circle of annular protrusions, and the plurality of first annular protrusions are arranged around the outside of the plurality of second annular protrusions; and The first reflective metal layer also includes a connecting wire, which is annular and arranged around multiple first annular protrusions. The connecting wire is respectively connected to the multiple first annular protrusions to form an integrated structure, and the surface of the connecting wire close to the surface electrode layer is flush with the surface of the first annular protrusion close to the surface electrode layer.

8. The light emitting diode according to any one of claims 2 to 4, wherein: The protrusion structure includes a disc-shaped protrusion.

9. The light emitting diode according to claim 8, wherein: The first electrode further includes a spacer electrode layer located on a side of the first reflective metal layer close to the light-emitting functional layer, and a second reflective metal layer located between the spacer electrode layer and the surface electrode layer; and The second reflective metal layer includes a plurality of reflective metal portions that are spaced apart from each other, and the surface electrode layer is in contact with the spaced electrode layer through gaps between adjacent reflective metal portions.

10. The light emitting diode according to claim 9, wherein: The edge profile of the reflective metal portion is rounded.

11. The light emitting diode according to claim 10, wherein: The orthographic projections of the plurality of reflective metal parts on the virtual plane partially overlap with the orthographic projections of the plurality of pancake-shaped protrusions on the virtual plane, and the virtual plane is perpendicular to the light emitting direction of the light emitting diode; or, The orthographic projections of the plurality of reflective metal parts on the virtual plane respectively coincide with the orthographic projections of the plurality of pancake-shaped protrusions on the virtual plane.

12. The light emitting diode according to any one of claims 9 to 11, wherein: Along the light emitting direction of the light emitting diode, the thickness of the second reflective metal layer is less than the thickness of the first reflective metal layer.

13. A display substrate, wherein: The display substrate comprises a plurality of light emitting devices, at least one of the light emitting devices comprises a light emitting diode according to any one of claims 1-12.

14. The display substrate according to claim 13, wherein: The plurality of light emitting devices include a red light emitting device, a green light emitting device, and a blue light emitting device, and the blue light emitting device includes the light emitting diode.

15. A display device, wherein: The display device comprises the display substrate according to claim 13 or 14.

Images