Light-emitting element and display substrate

Abstract

At least one embodiment of the present disclosure provides a light-emitting element and a display substrate. The light-emitting element comprises a first electrode, a light-emitting functional layer and a second electrode, which are sequentially stacked in a first direction, wherein the light-emitting functional layer comprises a first organic layer, a first light-emitting layer, a second organic layer, a second light-emitting layer, a spacer layer, a third light-emitting layer and a third organic layer, which are sequentially stacked in the first direction; the material of the second light-emitting layer comprises a first electron-blocking material and a light-emitting material doped in the first electron-blocking material, the light-emitting material comprising at least one of a platinum complex and an iridium complex; and the material of the spacer layer comprises a second electron-blocking material. In the embodiments of the present disclosure, the original phenomenon of exciton quenching caused by an excessively high concentration of excitons on an interface of the second light-emitting layer is eliminated, and therefore the light-emitting element can emit light in the middle region of the second light-emitting layer, thereby improving the luminous efficacy of the light-emitting element and prolonging the service life of a display substrate.

Description

Light-emitting element and display substrate Technical Field

[0001] Embodiments of the present disclosure relate to a light emitting element and a display substrate. Background Art

[0002] Currently, the technology for flexible display panels using organic light-emitting diodes (OLEDs) is maturing. These panels offer a wide range of advantages, including bendability, high contrast, a wide color gamut, a thin and lightweight design, self-luminescence, low power consumption, and a wide viewing angle. These advantages hold great promise for future development and have become a research hotspot and a key area of ​​technological development for major manufacturers. Organic light-emitting diode (OLED) displays are widely used in a variety of electronic products, from small devices like smart bracelets, smartwatches, smartphones, and tablets to larger devices like laptops, desktop computers, and televisions. Consequently, market demand for active-matrix organic light-emitting diode (OLED) displays is also growing rapidly.

[0003] Summary of the Invention

[0004] At least one embodiment of the present disclosure provides a light-emitting element and a display substrate, wherein the light-emitting functional layer in the light-emitting element includes a first organic layer, a first light-emitting layer, a second organic layer, a second light-emitting layer, a spacer layer, a third light-emitting layer and a third organic layer stacked in sequence in a first direction, the material of the second light-emitting layer includes a first electron blocking material and a light-emitting material doped in the first electron blocking material, the light-emitting material includes at least one of a platinum complex and an iridium complex, and the material of the spacer layer includes a second electron blocking material. In the embodiment of the present disclosure, the material of the second light-emitting layer includes the first electron blocking material and the light-emitting material doped in the first electron blocking material, and the light-emitting material includes at least one of a platinum complex and an iridium complex, and the material of the spacer layer includes the second electron blocking material, thereby eliminating the phenomenon of exciton quenching due to excessive exciton concentration at the interface of the original second light-emitting layer, thereby enabling the light-emitting element to emit light in the middle region of the second light-emitting layer, thereby improving the luminous efficiency of the light-emitting element and extending the service life of the display substrate.

[0005] At least one embodiment of the present disclosure provides a light-emitting element, which includes: a first electrode, a light-emitting functional layer, and a second electrode stacked in sequence in a first direction, wherein the light-emitting functional layer includes a first organic layer, a first light-emitting layer, a second organic layer, a second light-emitting layer, a spacer layer, a third light-emitting layer, and a third organic layer stacked in sequence in the first direction; a material of the second light-emitting layer includes a first electron-blocking material and a light-emitting material doped in the first electron-blocking material, the light-emitting material includes at least one of a platinum complex and an iridium complex; a material of the spacer layer includes a second electron-blocking material.

[0006] For example, in the light-emitting element provided in at least one embodiment of the present disclosure, the first electron blocking material and the second electron blocking material are the same.

[0007] For example, in the light-emitting element provided in at least one embodiment of the present disclosure, the spacer layer is sandwiched between the second light-emitting layer and the third light-emitting layer, and is in direct contact with both the second light-emitting layer and the third light-emitting layer.

[0008] For example, in the light-emitting element provided in at least one embodiment of the present disclosure, the first organic layer includes a hole injection layer, a first hole transport layer and a first electron blocking layer stacked in sequence; the second organic layer includes a first hole blocking layer, a first electron transport layer, a charge generation layer and a second hole transport layer stacked in sequence; the third organic layer includes a second hole blocking layer and a second electron transport layer stacked in sequence.

[0009] For example, in the light-emitting element provided in at least one embodiment of the present disclosure, the first light-emitting layer is arranged on the surface of the first electron blocking layer away from the hole injection layer, and is in direct contact with the first electron blocking layer; the first hole blocking layer is arranged on the surface of the first light-emitting layer away from the hole injection layer, and is in direct contact with the first light-emitting layer; the second hole transport layer is arranged on the surface of the second light-emitting layer close to the hole injection layer, and is in direct contact with the second light-emitting layer; the second hole blocking layer is arranged on the surface of the third light-emitting layer away from the hole injection layer, and is in direct contact with the third light-emitting layer.

[0010] For example, in the light-emitting element provided in at least one embodiment of the present disclosure, the light-emitting functional layer further includes an electron injection layer, and the electron injection layer is disposed on a side of the third organic layer away from the hole injection layer.

[0011] For example, in the light-emitting element provided in at least one embodiment of the present disclosure, the platinum complex includes octaethylporphyrin platinum; the iridium complex includes at least one of bis(1-phenylisoquinoline)(acetylacetonate)iridium and bis(2-(2'-benzothienyl)pyridine-N,C3')(acetylacetonate)iridium.

[0012] For example, in the light-emitting element provided in at least one embodiment of the present disclosure, the material of the hole injection layer includes a metal oxide, or a hole transport material doped with a p-type dopant of a strong electron-withdrawing system.

[0013] For example, in the light-emitting element provided in at least one embodiment of the present disclosure, the metal oxide includes at least one of molybdenum oxide, titanium oxide, vanadium oxide, rhenium oxide, ruthenium oxide, chromium oxide, zirconium oxide, hafnium oxide, tantalum oxide, silver oxide, tungsten oxide and manganese oxide; the hole transport material includes at least one of hexacyanohexaazatriphenylene, 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane and 1,2,3-tris[(cyano)(4-cyano-2,3,5,6-tetrafluorophenyl)methylene]cyclopropane.

[0014] For example, in the light-emitting element provided in at least one embodiment of the present disclosure, the charge generation layer includes a hole generation layer, and the materials of the first hole transport layer, the first electron blocking layer, the second hole transport layer and the hole generation layer all include at least one of aromatic amines, dimethylfluorene and carbazole.

[0015] For example, in the light-emitting element provided in at least one embodiment of the present disclosure, the materials of the first hole transport layer, the first electron blocking layer, the second hole transport layer and the hole generating layer all include at least one of 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl, N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine, 4-phenyl-4'-(9-phenylfluorene-9-yl)triphenylamine, 4,4'-bis[N-(9,9-dimethylfluorene-2-yl)-N-phenylamino]biphenyl, 4,4'-di(9-carbazolyl)biphenyl and 9-phenyl-3-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole.

[0016] For example, in the light-emitting element provided in at least one embodiment of the present disclosure, the charge generation layer also includes an electron generation layer, and the materials of the first hole blocking layer, the second hole blocking layer, the first electron transport layer, the second electron transport layer and the electron generation layer all include at least one of 2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole, 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene, 3-(4-tert-butylphenyl)-4-phenyl-5-(4-biphenyl)-1,2,4-triazole, 3-(4-tert-butylphenyl)-4-(4-ethylphenyl)-5-(4-biphenyl)-1,2,4-triazole, bathophenanthroline, 4-bromo-3-cyanopyridine and 4,4'-bis(5-methylbenzoxazol-2-yl)stilbene.

[0017] For example, in the light-emitting element provided in at least one embodiment of the present disclosure, the first electron blocking material and the second electron blocking material both include at least one of 4-(dicyanomethylene)-2-methyl-6-(4-dimethylaminophenylvinyl)-4H-pyran and 4-(dicyanomethylene)-2-tert-butyl-6-(1,1,7,7-tetramethyljulonitrile-9-enyl)-4H-pyran.

[0018] For example, in the light-emitting element provided in at least one embodiment of the present disclosure, the material of the electron injection layer includes lithium fluoride, ytterbium, magnesium and calcium metal elements, and at least one of ytterbium, magnesium and calcium oxides.

[0019] For example, in the light-emitting element provided in at least one embodiment of the present disclosure, the material of the third light-emitting layer includes a third electron blocking material and the light-emitting material doped in the third electron blocking material, and the mass percentage of the light-emitting material doped in the second light-emitting layer is less than half of the mass percentage of the light-emitting material doped in the third light-emitting layer.

[0020] For example, in the light-emitting element provided in at least one embodiment of the present disclosure, the mass percentage of the light-emitting material doped in the second light-emitting layer is 0.4% to 1%, and the mass percentage of the light-emitting material doped in the third light-emitting layer is 1.5% to 2.2%.

[0021] For example, in the light-emitting element provided in at least one embodiment of the present disclosure, in the first direction, the thickness of the spacer layer is less than or equal to half the thickness of the third light-emitting layer, and the thickness of the second light-emitting layer is less than or equal to the thickness of the third light-emitting layer.

[0022] For example, in the light-emitting element provided in at least one embodiment of the present disclosure, in the first direction, the thickness of the third organic layer is less than or equal to the thickness of the first organic layer.

[0023] For example, in the light-emitting element provided in at least one embodiment of the present disclosure, the thickness of the first light-emitting layer is less than or equal to the thickness of the thickest layer among the sublayers of the first organic layer and the sublayers of the third organic layer.

[0024] For example, in the light-emitting element provided in at least one embodiment of the present disclosure, the light-emitting element is a red light-emitting element.

[0025] At least one embodiment of the present disclosure further provides a display substrate, which includes the light-emitting element described in any of the above embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings of the embodiments will be briefly introduced below. Obviously, the drawings in the following description only relate to some embodiments of the present disclosure, rather than limiting the present disclosure.

[0027] FIG1 is a schematic diagram of a cross-sectional structure of stacked layers in a light-emitting functional layer of a light-emitting element;

[0028] FIG2 is a schematic diagram of a cross-sectional structure of a light-emitting element provided by at least one embodiment of the present disclosure;

[0029] FIG3 is a schematic cross-sectional structure diagram of stacked layers in a light-emitting functional layer of a light-emitting element provided by at least one embodiment of the present disclosure; and

[0030] FIG4 is a block diagram of a display substrate provided by at least one embodiment of the present disclosure. DETAILED DESCRIPTION

[0031] To make the purpose, technical solutions, and advantages of the embodiments of the present disclosure more clear, the technical solutions of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0032] Unless otherwise defined, the technical or scientific terms used in this disclosure should have the usual meanings understood by persons of ordinary skill in the field to which this disclosure belongs. The words "first", "second" and similar terms used in this disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. Words such as "include" or "comprise" mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Words such as "connect" or "connected" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0033] Unless otherwise defined, the features such as "parallel", "perpendicular" and "same" used in the embodiments of the present invention include the situations of "parallel", "perpendicular", "same" in a strict sense, as well as the situations of "approximately parallel", "approximately perpendicular", "approximately the same" and the like that contain a certain error. For example, the above-mentioned "approximately" may mean that the difference between the compared objects is 10% of the average value of the compared objects, or within 5%. When the number of a component or element is not specifically indicated below in the embodiments of the present invention, it means that the component or element may be one or more, or may be understood as at least one. "At least one" refers to one or more, and "multiple" refers to at least two. The "same-layer setting" in the embodiments of the present invention refers to the relationship between multiple film layers formed by the same material after the same step (for example, a one-step patterning process). The "same layer" here does not always mean that the thickness of multiple film layers is the same or the height of multiple film layers in the cross-sectional view is the same.

[0034] Figure 1 is a schematic diagram of the cross-sectional structure of each layer in a light-emitting functional layer of a light-emitting element. As shown in Figure 1, the light-emitting functional layer includes a hole injection layer 101, a first hole transport layer 102, a first electron blocking layer 103, a first light-emitting layer 104, a first hole blocking layer 105, a first electron transport layer 106, an electron generating layer 107, a hole generating layer 108, a second hole transport layer 109, a second electron blocking layer 110, a second light-emitting layer 111, a second hole blocking layer 112, a second electron transport layer 113 and an electron injection layer 114, wherein the hole injection layer 101, the first hole transport layer 102 and the first electron blocking layer 103 constitute a first organic layer 201, the first hole blocking layer 105, the first electron transport layer 106, the electron generating layer 107, the hole generating layer 108, the second hole transport layer 109, the second electron blocking layer 110, the second light-emitting layer 111, the second hole blocking layer 112, the second electron transport layer 113 and the electron injection layer 114 are stacked in sequence. The hole generation layer 107, the hole generation layer 108, the second hole transport layer 109 and the second electron blocking layer 110 constitute the second organic layer 202, and the second hole blocking layer 112 and the second electron transport layer 113 constitute the third organic layer 203. However, the inventors of the present disclosure have noticed that the light-emitting layers of the current red phosphorescent light-emitting devices are all electron-biased, which causes the exciton recombination area to be concentrated on the interface between the second electron blocking layer 110 and the second light-emitting layer 111, which easily leads to quenching of the excitons due to excessive concentration. The exciton quenching will cause the luminous efficiency of the organic light-emitting device to be reduced, and the non-radiative transition will also generate a large amount of heat energy, which will accelerate the degradation of the interface between the second electron blocking layer 110 and the second light-emitting layer 111, thereby reducing the life of the organic light-emitting display device formed.

[0035] The inventors of the present disclosure have noted that the second electron blocking layer 110 in FIG. 1 can be split to form a new light-emitting layer and a spacer layer, thereby transferring the region where excitons recombine to the new light-emitting layer to achieve luminescence and improve luminescence efficiency. This can thereby avoid the problem of exciton quenching due to excessive exciton concentration at the interface between the second electron blocking layer 110 and the second light-emitting layer 111 in FIG. 1 . In addition, because the HOMO energy level of the red light-emitting material is shallower than the HOMO energy level of the first electron blocking material, a hole transport channel can be formed to reduce charge accumulation at the interface between the second hole transport layer and the first electron blocking material, thereby improving the capacitance of the resulting organic light-emitting diode display device.

[0036] For example, Figure 2 is a schematic diagram of the cross-sectional structure of a light-emitting element provided in at least one embodiment of the present disclosure, and Figure 3 is a schematic diagram of the cross-sectional structure of the stacking of various layers in the light-emitting functional layer of a light-emitting element provided in at least one embodiment of the present disclosure. Combining Figures 2 and 3, the light-emitting element 500 includes: a first electrode 501, a light-emitting functional layer 502, and a second electrode 503 stacked in sequence in a first direction X.

[0037] For example, the entire light-emitting element 500 is formed on a base substrate, with a first electrode 501 located between a light-emitting functional layer 502 and the base substrate; and a second electrode 503 located at least partially on a side of the light-emitting functional layer 502 away from the first electrode 501. In other words, the first electrode 501 and the second electrode 503 are located on opposite sides of the light-emitting functional layer 502 in a direction perpendicular to the main surface of the light-emitting functional layer 502 (i.e., a first direction X). The light-emitting functional layer 502 includes multiple sub-functional layers, i.e., the light-emitting functional layer 502 includes not only a film layer that directly emits light, but also functional film layers for assisting light emission, such as a hole transport layer, an electron transport layer, a hole blocking layer, an electron blocking layer, an electron generating layer, and a hole generating layer.

[0038] For example, in one embodiment, the first electrode 501 can be formed of a metal material, such as any one or more of magnesium (Mg), silver (Ag), copper (Cu), aluminum (Al), titanium (Ti), and molybdenum (Mo), or alloys of the above metals, such as aluminum-neodymium alloy (AlNd) or molybdenum-niobium alloy (MoNb). The first electrode 501 can be a single-layer structure or a multi-layer composite structure, such as Ti / Al / Ti, or the first electrode 501 can be a stack structure formed by a metal and a transparent conductive material, such as a stack structure of ITO / Ag / ITO or Mo / AlNd / ITO.

[0039] For example, in one example, the second electrode 503 can be formed of any one or more materials selected from magnesium (Mg), silver (Ag), and aluminum (Al), or can be an alloy made of any one or more of the above metals, or the second electrode 503 can also be formed of a transparent conductive material, such as indium tin oxide (ITO), etc., or the second electrode 503 can also be a multilayer composite structure formed of metal and transparent conductive material.

[0040] For example, in one embodiment, the first electrode 501 may be an anode, and the second electrode 503 may be a cathode. For example, the cathode may be formed of a material with high conductivity and low work function, such as a metal material. For example, the anode may be formed of a transparent conductive material with a high work function.

[0041] For example, as shown in FIG3 , the light-emitting functional layer 502 includes a first organic layer 401, a first light-emitting layer 304, a second organic layer 402, a second light-emitting layer 310, a spacer layer 315, a third light-emitting layer 311, and a second organic layer 403, which are sequentially stacked in a first direction X. For example, referring to FIG2 and FIG3 , when the light-emitting functional layer 502 is placed in the light-emitting element 500, the first organic layer 401 is in direct contact with the first electrode 501, that is, the first organic layer 401 is located on the side of the second organic layer 402 that is closer to the first electrode 501.

[0042] For example, in one example, the main surface of the light-emitting functional layer 502 is a horizontal plane, and the first direction X is, for example, a vertical direction perpendicular to the horizontal plane, but the embodiments of the present disclosure are not limited thereto, as long as the first direction X is perpendicular to the main surface of the light-emitting functional layer 502.

[0043] For example, as shown in FIG3 , the material of the second light-emitting layer 310 includes a first electron blocking material and a light-emitting material doped in the first electron blocking material, and the light-emitting material includes at least one of a platinum complex and an iridium complex. The material of the spacer layer 315 includes a second electron blocking material. That is, relative to the structure shown in FIG1 , the structure in FIG3 is a two-layer structure in which the second electron blocking layer 110 in FIG1 is split into two layers, one of which is the second light-emitting layer 310 and the other is the spacer layer 315. For example, the structure shown in FIG3 can transfer the area of ​​exciton recombination to the second light-emitting layer 310 to achieve luminescence and improve luminous efficiency, thereby avoiding the problem of exciton quenching caused by excessive exciton concentration at the interface between the second electron blocking layer 110 and the second light-emitting layer 111 in FIG1 . In addition, since the HOMO energy level of the red light-emitting material is shallower than the HOMO energy level of the first electron blocking material, a hole transport channel can be formed to reduce the charge accumulation at the interface between the second hole transport layer and the first electron blocking material, thereby improving the capacitance of the organic light-emitting diode display device finally formed.

[0044] For example, the first and second electron-blocking materials have high LUMO (lowest unoccupied molecular orbital) energy levels, effectively preventing electron transport and enabling the formation of exciton recombination zones in the light-emitting layer. Furthermore, the first and second electron-blocking materials have high hole mobility, thereby facilitating hole transport. The first and second electron-blocking materials also have good stability, can form films of uniform thickness and density, and have high triplet energy levels, thereby preventing the transport of triplet excitons.

[0045] For example, in one example, the first electron blocking material and the second electron blocking material each include at least one of 4-(dicyanomethylene)-2-methyl-6-(4-dimethylaminophenylvinyl)-4H-pyran and 4-(dicyanomethylene)-2-tert-butyl-6-(1,1,7,7-tetramethyljulonitrile-9-enyl)-4H-pyran.

[0046] For example, in one example, the first electron blocking material and the second electron blocking material are the same, for example, the first electron blocking material and the second electron blocking material are both 4-(dicyanomethylene)-2-methyl-6-(4-dimethylaminophenyl)-4H-pyran, or both are 4-(dicyanomethylene)-2-tert-butyl-6-(1,1,7,7-tetramethyljulonitrile-9-enyl)-4H-pyran. When the first electron blocking material and the second electron blocking material are the same, the types of selected materials can be reduced. Of course, the first electron blocking material and the second electron blocking material can also be different, and the embodiments of the present disclosure are not limited to this.

[0047] For example, in another example, the first electron blocking material and the second electron blocking material can also be one of 4,4',4"-tris(carbazol-9-yl)triphenylamine (TCTA) and 4,4'-cyclohexylbis[N,N-bis(4-methylphenyl)aniline] (TAPC).

[0048] For example, in one example, the first electron blocking material and the second electron blocking material are the same, for example, the first electron blocking material and the second electron blocking material are both 4,4',4"-tris(carbazol-9-yl)triphenylamine (TCTA), or both are 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] (TAPC). When the first electron blocking material and the second electron blocking material are the same, the number of types of materials to be selected can be reduced. Of course, the first electron blocking material and the second electron blocking material can also be different, and the embodiments of the present disclosure are not limited to this.

[0049] For example, in one embodiment, the luminescent material is a platinum complex, and the platinum complex includes octaethylporphyrin platinum.

[0050] For example, in another example, the luminescent material is an iridium complex, and the iridium complex includes at least one of bis(1-phenylisoquinolinato)(acetylacetonate)iridium and bis(2-(2'-benzothienyl)pyridine-N,C3')(acetylacetonate)iridium.

[0051] For example, in another example, the luminescent material is a mixture of a platinum complex and an iridium complex, for example, the luminescent material is a mixture of octaethylporphyrin platinum, bis(1-phenylisoquinoline)(acetylacetonate)iridium and bis(2-(2'-benzothienyl)pyridine-N,C3')(acetylacetonate)iridium.

[0052] For example, the light-emitting element 500 is a red light-emitting element. Using at least one of a platinum complex and an iridium complex as the light-emitting material of the red light-emitting element can make the color purity of the red light emitted from the light-emitting element higher.

[0053] For example, as shown in FIG3 , the spacer layer 315 is sandwiched between the second light-emitting layer 310 and the third light-emitting layer 311, and the spacer layer 315 is in direct contact with the second light-emitting layer 310 and the third light-emitting layer 311. The material of the spacer layer 315 includes a second electron blocking material. The spacer layer 315 makes the region where the excitons recombine is the middle region of the second light-emitting layer 310 and the middle region of the third light-emitting layer 311, thereby improving the luminous efficiency of the light-emitting element, thereby avoiding the problem of exciton quenching due to excessive exciton concentration at the interface of the second electron blocking layer 110 and the second light-emitting layer 111 in FIG1 . In addition, since the HOMO energy level of the red light-emitting material is shallower than the HOMO energy level of the first electron blocking material, a hole transport channel can be formed to reduce the charge accumulation at the interface of the second hole transport layer and the first electron blocking material, thereby improving the capacitance of the organic light-emitting diode display device finally formed.

[0054] For example, as shown in FIG3 , the first organic layer 401 includes a hole injection layer 301, a first hole transport layer 302, and a first electron blocking layer 303, which are sequentially stacked. The second organic layer 402 includes a first hole blocking layer 305, a first electron transport layer 306, a charge generation layer 307 / 308, and a second hole transport layer 309, which are sequentially stacked. The third organic layer 403 includes a second hole blocking layer 312 and a second electron transport layer 313, which are sequentially stacked.

[0055] For example, when the structure shown in Figure 3 is placed in the light-emitting element shown in Figure 2, in the first organic layer 401, the hole injection layer 301 is on the side of the first hole transport layer 302 and the first electron blocking layer 303 close to the first electrode 501; in the second organic layer 402, the first hole blocking layer 305 is on the side of the first electron transport layer 306, the charge generation layer 307 / 308 and the second hole transport layer 309 close to the first electrode 501; in the third organic layer 403, the second hole blocking layer 312 is on the side of the second electron transport layer 313 close to the first electrode 501.

[0056] For example, as shown in FIG3 , the first light-emitting layer 304 is disposed on a surface of the first electron blocking layer 303 that is distal from the hole injection layer 301 and is in direct contact with the first electron blocking layer 303. The first hole blocking layer 305 is disposed on a surface of the first light-emitting layer 304 that is distal from the hole injection layer 301 and is in direct contact with the first light-emitting layer 304. The second hole transport layer 309 is disposed on a surface of the second light-emitting layer 310 that is proximal to the hole injection layer 301 and is in direct contact with the second light-emitting layer 310. The second hole blocking layer 312 is disposed on a surface of the third light-emitting layer 311 that is distal from the hole injection layer 301 and is in direct contact with the third light-emitting layer 311. The first light-emitting layer 304, first electron blocking layer 303, hole injection layer 301, first hole blocking layer 305, second hole transport layer 309, second light-emitting layer 310, and second hole blocking layer 312 may refer to their corresponding conventional functions and are not limited in the embodiments of the present disclosure.

[0057] For example, as shown in FIG3 , the light-emitting functional layer 502 further includes an electron injection layer 314, which is disposed on a side of the third organic layer 403 away from the hole injection layer 301. For example, the material of the electron injection layer 314 includes at least one of lithium fluoride, ytterbium, magnesium, and calcium metal elements, and oxides of ytterbium, magnesium, and calcium. For example, the material of the electron injection layer 314 can be a mixture of lithium fluoride and magnesium oxide, a mixture of lithium fluoride, magnesium oxide, and calcium oxide, or a mixture of lithium fluoride, ytterbium metal elements, and magnesium oxide.

[0058] For example, in one example, the material of the hole injection layer 301 includes metal oxide, or a hole transport material doped with a p-type dopant of a strong electron-withdrawing system.

[0059] For example, the metal oxide forming the hole injection layer 301 includes at least one of molybdenum oxide, titanium oxide, vanadium oxide, rhenium oxide, ruthenium oxide, chromium oxide, zirconium oxide, hafnium oxide, tantalum oxide, silver oxide, tungsten oxide, and manganese oxide. The hole transport material forming the hole injection layer 301 includes at least one of hexacyanohexaazatriphenylene, 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane, and 1,2,3-tris[(cyano)(4-cyano-2,3,5,6-tetrafluorophenyl)methylene]cyclopropane.

[0060] For example, as shown in FIG3 , the charge generation layer includes a hole generation layer 308 , and the materials of the first hole transport layer 302 , the first electron blocking layer 303 , the second hole transport layer 309 and the hole generation layer 308 all include at least one of aromatic amines, dimethylfluorene and carbazoles.

[0061] For example, as shown in Figure 3, the materials of the first hole transport layer 302, the first electron blocking layer 303, the second hole transport layer 309 and the hole generating layer 308 all include at least one of 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl, N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine, 4-phenyl-4'-(9-phenylfluorene-9-yl)triphenylamine, 4,4'-bis[N-(9,9-dimethylfluorene-2-yl)-N-phenylamino]biphenyl, 4,4'-di(9-carbazolyl)biphenyl and 9-phenyl-3-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole.

[0062] For example, in another example, the materials of the first hole transport layer 302, the first electron blocking layer 303, the second hole transport layer 309 and the hole generation layer 308 all include 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline], N4,N4'-di(naphthalene-1-yl)-N4,N4'-bis(4-vinylphenyl)biphenyl-4,4'-diamine, N,N'-bis(3-methylphenyl)-N,N'-bis(phenyl)-2,7-diamine-9,9-spirobifluorene, N,N,N',N'-tetrakis-(3-methylphenyl)-3-3'-dimethyl-p-diaminobiphenyl, 2,2'-bis(3-(N,N-di-p-tolylamino)phenyl)biphenyl, N,N'-di(naphthalene-2-yl)-N,N'-di(phenyl)diaminobiphenyl, N,N' -Di(naphthyl)-N,N'-diphenyl-2,7-diamino-9,9-spirobifluorene, N,N'-di(3-methylphenyl)-N,N'-diphenyl-2,7-diamino-9,9-dimethylfluorene, N,N'-di(naphthyl)-N,N'-diphenyl-2,7-diamino-9,9-dimethylfluorene, N,N'-di(3-methylphenyl)-N,N' – Diphenyl-2,7-diamino-9,9-diphenylfluorene, N,N'-di(naphthalene-1-yl)-N,N'-diphenyl-2,7-diamino-9,9-diphenylfluorene, N,N'-di(naphthalene-1-yl)-N,N'-diphenyl-2,2'-dimethyldiaminobiphenyl, 2,2',7,7'-tetrakis(N,N-diphenylamino)-2,7-diamino-9,9- One or more of spirobifluorene, 9,9-bis[4-(N,N-dinaphthyl-2-yl-amino)phenyl]-9H-fluorene, 9,9-[4-(N-naphthyl-1-yl-N-aniline)-phenyl]-9H-fluorene, 2,2'-bis[N,N-bis(4-phenyl)amino]-9,9-spirobifluorene, 2,2'-bis(N,N-phenylamino)-9,9-spirobifluorene, N,N'-diphenyl-N,N'-(1-naphthyl)-1,1'-biphenyl-4,4'-diamine and 4,4'-bis[N-(p-tolyl)-N-phenyl-amino]diphenyl.

[0063] For example, as shown in Figure 3, the charge generation layer also includes an electron generation layer 307, and the materials of the first hole blocking layer 305, the second hole blocking layer 312, the first electron transport layer 306, the second electron transport layer 313 and the electron generation layer 307 all include at least one of 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole, 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene, 3-(4-tert-butylphenyl)-4-phenyl-5-(4-biphenylyl)-1,2,4-triazole, 3-(4-tert-butylphenyl)-4-(4-ethylphenyl)-5-(4-biphenylyl)-1,2,4-triazole, bathophenanthroline, 4-bromo-3-cyanopyridine and 4,4'-bis(5-methylbenzoxazol-2-yl)stilbene.

[0064] For example, in another example, the materials of the first hole blocking layer 305, the second hole blocking layer 312, the first electron transport layer 306, the second electron transport layer 313 and the electron generation layer 307 all include one or more of tris[2,4,6-trimethyl-3-(3-pyridyl)phenyl]borane, 1,3,5-tris[(3-pyridyl)-3-phenyl]benzene, 1,3-bis[3,5-di(3-pyridyl)phenyl]benzene and 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene.

[0065] For example, in one embodiment, the charge generation layer is configured to generate carriers, transport carriers, and inject carriers. For example, the electron generation layer 307 material may also include an n-type doped organic layer / inorganic metal oxide, such as Alq3:Mg / WO3, Bphen:Li / MoO3, BCP:Li / V2O5, and BCP:Cs / V2O5; or an n-type doped organic layer / organic layer, such as Alq3:Li / HAT-CN; or an n-type doped organic layer / p-type doped organic layer, such as BPhen:Cs / NPB:F4-TCNQ, Alq3:Li / NPB:FeCl3, TPBi:Li / NPB:FeCl3, and Alq3:Mg / m-MTDATA:F4-TCNQ; or an undoped type, such as F16CuPc / CuPc and Al / WO3 / Au.

[0066] For example, as shown in FIG3 , the material of the third light-emitting layer 311 includes a third electron-blocking material and a light-emitting material doped in the third electron-blocking material, and the mass percentage of the light-emitting material doped in the second light-emitting layer 310 is less than half the mass percentage of the light-emitting material doped in the third light-emitting layer 311. For example, because the third light-emitting layer 311 is closer to the display surface than the second light-emitting layer 310 when the light-emitting element is used in a display panel, the color purity of the light emitted from the third light-emitting layer 311 needs to be higher than the color purity of the light emitted from the second light-emitting layer 310.

[0067] For example, in the structure shown in FIG3 , in one example, the mass percentage of the light-emitting material doped in the second light-emitting layer 310 is 0.4% to 1%, and the mass percentage of the light-emitting material doped in the third light-emitting layer 311 is 1.5% to 2.2%.

[0068] For example, in the structure shown in FIG3 , in another example, the mass percentage of the light-emitting material doped in the second light-emitting layer 310 is 0.6% to 0.8%, and the mass percentage of the light-emitting material doped in the third light-emitting layer 311 is 1.6% to 2%.

[0069] For example, in the structure shown in FIG3 , in yet another example, the mass percentage of the light-emitting material doped in the second light-emitting layer 310 is 0.7%, and the mass percentage of the light-emitting material doped in the third light-emitting layer 311 is 1.8%.

[0070] For example, as shown in Figure 3, in the first direction X, the thickness of the spacer layer 315 is less than or equal to half the thickness of the third light-emitting layer 311, and the thickness of the second light-emitting layer 310 is less than or equal to the thickness of the third light-emitting layer 311. Setting the thickness of the spacer layer 315 to be less than or equal to half the thickness of the third light-emitting layer 311 can achieve the separation of the second light-emitting layer 310 and the third light-emitting layer 311 while making the light-emitting element as light and thin as possible.

[0071] For example, as shown in FIG3 , in the first direction X, the thickness of the third organic layer 403 is less than or equal to the thickness of the first organic layer 401. For example, in one example, the thickness of the third organic layer 403 is 1 / 4 to 1 / 4 of the thickness of the first organic layer 401. For example, in another example, the thickness of the third organic layer 403 is 1 / 3 to 3 / 4 of the thickness of the first organic layer 401.

[0072] For example, as shown in FIG. 3 , the thickness of the first light emitting layer 304 is less than or equal to the thickness of the thickest layer among the sublayers of the first organic layer 401 and the sublayers of the third organic layer 403 .

[0073] For example, in combination with Figures 1 and 3, the method for manufacturing a light-emitting element provided by an embodiment of the present disclosure may include: cleaning a substrate formed of indium tin oxide to form a first electrode 501, and sequentially forming a hole injection layer 301, a first hole transport layer 302 and a first electron blocking layer 303, a first light-emitting layer 304, a first hole blocking layer 305, a first electron transport layer 306, an electron generation layer 307, a hole generation layer 308, a second hole transport layer 309, a second light-emitting layer 310, a spacer layer 315, a third light-emitting layer 311, a second hole blocking layer 312, a second electron transport layer 313 and an electron injection layer 314 on the first electrode 501.

[0074] For example, in one example, the first light-emitting layer 304 , the second light-emitting layer 310 and the third light-emitting layer 311 all include the same electron blocking material and the same type of light-emitting material doped in the same electron blocking material, which can reduce the number of materials to be selected.

[0075] For example, in one example, the materials of the first electron transport layer 306 and the second electron transport layer 313 both include an electron transport material and Liq doped in the electron transport material.

[0076] For example, in one example, the host material of the electron generation layer 307 is doped with Yb metal, and the host material of the hole generation layer 308 is doped with F4TCNQ.

[0077] For example, referring to the following comparative examples 1 to 3, the performance of the light-emitting element provided by the embodiments of the present disclosure when used in a display panel can be studied based on the following embodiments 1 to 8.

[0078] Example 1:

[0079] The thickness of the hole injection layer is 100 angstroms, the thickness of the first hole transport layer is 250 angstroms, the thickness of the first electron blocking layer is 360 angstroms, the thickness of the first light-emitting layer is 350 angstroms, the thickness of the first hole blocking layer is 50 angstroms, the thickness of the first electron transport layer is 160 angstroms, the thickness of the electron generating layer is 100 angstroms, the thickness of the hole generating layer is 100 angstroms, the thickness of the second hole transport layer is 90 angstroms, the thickness of the second light-emitting layer is 300 angstroms, the thickness of the spacer layer is 200 angstroms, the thickness of the third light-emitting layer is 450 angstroms, the thickness of the second hole blocking layer is 50 angstroms, the thickness of the second electron transport layer is 350 angstroms, and the mass percentage of the light-emitting material doped in the first electron blocking material in the second light-emitting layer is 0.5%, and the mass percentage of the light-emitting material doped in the third electron blocking material in the third light-emitting layer is 2%.

[0080] Example 2:

[0081] The thickness of the hole injection layer is 90 angstroms, the thickness of the first hole transport layer is 260 angstroms, the thickness of the first electron blocking layer is 350 angstroms, the thickness of the first light-emitting layer is 340 angstroms, the thickness of the first hole blocking layer is 55 angstroms, the thickness of the first electron transport layer is 155 angstroms, the thickness of the electron generating layer is 90 angstroms, the thickness of the hole generating layer is 110 angstroms, the thickness of the second hole transport layer is 85 angstroms, the thickness of the second light-emitting layer is 250 angstroms, the thickness of the spacer layer is 150 angstroms, the thickness of the third light-emitting layer is 440 angstroms, the thickness of the second hole blocking layer is 50 angstroms, the thickness of the second electron transport layer is 330 angstroms, and the mass percentage of the light-emitting material doped in the first electron blocking material in the second light-emitting layer is 0.6%, and the mass percentage of the light-emitting material doped in the third electron blocking material in the third light-emitting layer is 1.8%.

[0082] Example 3:

[0083] The thickness of the hole injection layer is 90 angstroms, the thickness of the first hole transport layer is 250 angstroms, the thickness of the first electron blocking layer is 355 angstroms, the thickness of the first light-emitting layer is 345 angstroms, the thickness of the first hole blocking layer is 50 angstroms, the thickness of the first electron transport layer is 150 angstroms, the thickness of the electron generating layer is 110 angstroms, the thickness of the hole generating layer is 110 angstroms, the thickness of the second hole transport layer is 95 angstroms, the thickness of the second light-emitting layer is 300 angstroms, the thickness of the spacer layer is 180 angstroms, the thickness of the third light-emitting layer is 445 angstroms, the thickness of the second hole blocking layer is 55 angstroms, the thickness of the second electron transport layer is 335 angstroms, and the mass percentage of the light-emitting material doped in the first electron blocking material in the second light-emitting layer is 0.8%, and the mass percentage of the light-emitting material doped in the third electron blocking material in the third light-emitting layer is 2%.

[0084] Example 4:

[0085] The thickness of the hole injection layer is 100 angstroms, the thickness of the first hole transport layer is 260 angstroms, the thickness of the first electron blocking layer is 365 angstroms, the thickness of the first light-emitting layer is 355 angstroms, the thickness of the first hole blocking layer is 45 angstroms, the thickness of the first electron transport layer is 152 angstroms, the thickness of the electron generating layer is 95 angstroms, the thickness of the hole generating layer is 105 angstroms, the thickness of the second hole transport layer is 88 angstroms, the thickness of the second light-emitting layer is 260 angstroms, the thickness of the spacer layer is 220 angstroms, the thickness of the third light-emitting layer is 448 angstroms, the thickness of the second hole blocking layer is 52 angstroms, the thickness of the second electron transport layer is 340 angstroms, and the mass percentage of the light-emitting material doped in the first electron blocking material in the second light-emitting layer is 0.9%, and the mass percentage of the light-emitting material doped in the third electron blocking material in the third light-emitting layer is 2.2%.

[0086] Embodiment 5:

[0087] The thickness of the hole injection layer is 80 angstroms, the thickness of the first hole transport layer is 270 angstroms, the thickness of the first electron blocking layer is 370 angstroms, the thickness of the first light-emitting layer is 350 angstroms, the thickness of the first hole blocking layer is 60 angstroms, the thickness of the first electron transport layer is 162 angstroms, the thickness of the electron generating layer is 98 angstroms, the thickness of the hole generating layer is 102 angstroms, the thickness of the second hole transport layer is 94 angstroms, the thickness of the second light-emitting layer is 280 angstroms, the thickness of the spacer layer is 180 angstroms, the thickness of the third light-emitting layer is 442 angstroms, the thickness of the second hole blocking layer is 48 angstroms, the thickness of the second electron transport layer is 340 angstroms, and the mass percentage of the light-emitting material doped in the first electron blocking material in the second light-emitting layer is 1.0%, and the mass percentage of the light-emitting material doped in the third electron blocking material in the third light-emitting layer is 2.1%.

[0088] Example 6:

[0089] The thickness of the hole injection layer is 100 angstroms, the thickness of the first hole transport layer is 270 angstroms, the thickness of the first electron blocking layer is 370 angstroms, the thickness of the first light-emitting layer is 360 angstroms, the thickness of the first hole blocking layer is 55 angstroms, the thickness of the first electron transport layer is 170 angstroms, the thickness of the electron generating layer is 100 angstroms, the thickness of the hole generating layer is 98 angstroms, the thickness of the second hole transport layer is 88 angstroms, the thickness of the second light-emitting layer is 350 angstroms, the thickness of the spacer layer is 150 angstroms, the thickness of the third light-emitting layer is 438 angstroms, the thickness of the second hole blocking layer is 46 angstroms, the thickness of the second electron transport layer is 350 angstroms, and the mass percentage of the light-emitting material doped in the first electron blocking material in the second light-emitting layer is 0.5%, and the mass percentage of the light-emitting material doped in the third electron blocking material in the third light-emitting layer is 1.6%.

[0090] Embodiment seven:

[0091] The thickness of the hole injection layer is 90 angstroms, the thickness of the first hole transport layer is 260 angstroms, the thickness of the first electron blocking layer is 365 angstroms, the thickness of the first light-emitting layer is 350 angstroms, the thickness of the first hole blocking layer is 48 angstroms, the thickness of the first electron transport layer is 166 angstroms, the thickness of the electron generating layer is 102 angstroms, the thickness of the hole generating layer is 96 angstroms, the thickness of the second hole transport layer is 90 angstroms, the thickness of the second light-emitting layer is 400 angstroms, the thickness of the spacer layer is 100 angstroms, the thickness of the third light-emitting layer is 435 angstroms, the thickness of the second hole blocking layer is 48 angstroms, the thickness of the second electron transport layer is 340 angstroms, and the mass percentage of the light-emitting material doped in the first electron blocking material in the second light-emitting layer is 0.4%, and the mass percentage of the light-emitting material doped in the third electron blocking material in the third light-emitting layer is 1.8%.

[0092] Embodiment 8:

[0093] The thickness of the hole injection layer is 90 angstroms, the thickness of the first hole transport layer is 250 angstroms, the thickness of the first electron blocking layer is 370 angstroms, the thickness of the first light-emitting layer is 345 angstroms, the thickness of the first hole blocking layer is 56 angstroms, the thickness of the first electron transport layer is 158 angstroms, the thickness of the electron generating layer is 105 angstroms, the thickness of the hole generating layer is 95 angstroms, the thickness of the second hole transport layer is 92 angstroms, the thickness of the second light-emitting layer is 380 angstroms, the thickness of the spacer layer is 160 angstroms, the thickness of the third light-emitting layer is 430 angstroms, the thickness of the second hole blocking layer is 50 angstroms, the thickness of the second electron transport layer is 340 angstroms, and the mass percentage of the light-emitting material doped in the first electron blocking material in the second light-emitting layer is 0.6%, and the mass percentage of the light-emitting material doped in the third electron blocking material in the third light-emitting layer is 2.2%.

[0094] Comparative Example 1:

[0095] The thickness of the hole injection layer is 100 angstroms, the thickness of the first hole transport layer is 250 angstroms, the thickness of the first electron blocking layer is 350 angstroms, the thickness of the first light-emitting layer is 350 angstroms, the thickness of the first hole blocking layer is 50 angstroms, the thickness of the first electron transport layer is 160 angstroms, the thickness of the electron generating layer is 100 angstroms, the thickness of the hole generating layer is 100 angstroms, the thickness of the second hole transport layer is 90 angstroms, the thickness of the second light-emitting layer is 300 angstroms, the thickness of the spacer layer is 200 angstroms, the thickness of the third light-emitting layer is 450 angstroms, the thickness of the second hole blocking layer is 50 angstroms, the thickness of the second electron transport layer is 360 angstroms, and the mass percentage of the light-emitting material doped in the first electron blocking material in the second light-emitting layer is 1.0%, and the mass percentage of the light-emitting material doped in the third electron blocking material in the third light-emitting layer is 2.0%.

[0096] Comparative Example 2:

[0097] The thickness of the hole injection layer is 100 angstroms, the thickness of the first hole transport layer is 250 angstroms, the thickness of the first electron blocking layer is 360 angstroms, the thickness of the first light-emitting layer is 350 angstroms, the thickness of the first hole blocking layer is 50 angstroms, the thickness of the first electron transport layer is 160 angstroms, the thickness of the electron generating layer is 100 angstroms, the thickness of the hole generating layer is 100 angstroms, the thickness of the second hole transport layer is 90 angstroms, the thickness of the second light-emitting layer is 280 angstroms, the thickness of the spacer layer is 250 angstroms, the thickness of the third light-emitting layer is 450 angstroms, the thickness of the second hole blocking layer is 50 angstroms, the thickness of the second electron transport layer is 350 angstroms, and the mass percentage of the light-emitting material doped in the first electron blocking material in the second light-emitting layer is 1.1%, and the mass percentage of the light-emitting material doped in the third electron blocking material in the third light-emitting layer is 1.9%.

[0098] Comparative Example 3:

[0099] The thickness of the hole injection layer is 100 angstroms, the thickness of the first hole transport layer is 170 angstroms, the thickness of the first electron blocking layer is 250 angstroms, the thickness of the first light-emitting layer is 350 angstroms, the thickness of the first hole blocking layer is 50 angstroms, the thickness of the first electron transport layer is 160 angstroms, the thickness of the electron generating layer is 140 angstroms, the thickness of the hole generating layer is 100 angstroms, the thickness of the second hole transport layer is 200 angstroms, the thickness of the second light-emitting layer is 300 angstroms, the thickness of the spacer layer is 200 angstroms, the thickness of the third light-emitting layer is 450 angstroms, the thickness of the second hole blocking layer is 50 angstroms, the thickness of the second electron transport layer is 350 angstroms, and the mass percentage of the light-emitting material doped in the first electron blocking material in the second light-emitting layer is 1.2%, and the mass percentage of the light-emitting material doped in the third electron blocking material in the third light-emitting layer is 1.8%.

[0100] The display effects of the display panels formed by the light-emitting elements in the above-mentioned Examples 1 to 8 and Comparative Examples 1 to 3 were tested, and the results were shown in Table 1 below.

[0101] Table 1: Display effects of display panels formed by the light-emitting elements in Examples 1 to 8 and Comparative Examples 1 to 3.

[0102] As can be seen from Table 1 above, taking Example 1 of the present disclosure as a benchmark, its voltage is 100%, Cd is 100%, and LT95@1000nit is 100%. In subsequent Examples 2 to 8, the voltages are 99%, 98%, 99%, 101%, 100%, 98%, and 97%, respectively. That is, relative to Example 1, the voltage deviation is basically 0-2%, and even the maximum voltage deviation is only 3%. However, in Comparative Examples 1 to 3, the voltages are 108%, 102%, and 110%, respectively. That is, the voltage deviations in Comparative Examples 1 and 3 are 8% and 10%, respectively, which means that the display panel voltage will be larger than that in the embodiment of the present disclosure. In the subsequent Examples 2 to 8, Cd is 102%, 104%, 101%, 105%, 98%, 99% and 101% respectively, that is, relative to Example 1, the current deviation is basically 1% to 5%, and even the maximum current deviation is only 5%; but in Comparative Examples 1 to 3, the current is 92%, 88% and 86% respectively, that is, the voltage deviation in Comparative Examples 1 to 3 is 8%, 12% and 14% respectively, that is, the display panel current will be larger than that in the embodiments of the present disclosure, and the deviation is larger. In the subsequent Examples 2 to 8, LT95@1000nit is 98%, 96%, 105%, 102%, 100%, 99% and 102% respectively, that is, relative to Example 1, the lifetime deviation is basically 0-5%, and even the maximum lifetime deviation is only 5%; however, in Comparative Examples 1 to 3, the lifetime deviations are 88%, 84% and 82% respectively, that is, the lifetime deviations in Comparative Examples 1 to 3 are 12%, 16% and 18% respectively, that is, relative to the display panels in the embodiments of the present disclosure, the lifetimes of the display panels in Comparative Examples 1 to 3 are shorter, and the deviation is larger. Through the above comparison, it can be found that when the mass proportion of the luminescent material doped in the second luminescent layer is larger, the voltage value of the final display panel will be too large, the current will be too small and the lifetime will be shortened.

[0103] For example, in one example, the light emitting element is a red light emitting element, and the test data are all obtained by taking the red light emitting element as an example.

[0104] At least one embodiment of the present disclosure further provides a display substrate. FIG4 is a block diagram of the display substrate provided by at least one embodiment of the present disclosure. As shown in FIG4 , the display substrate 600 includes the light-emitting element 500 in any of the above embodiments.

[0105] For example, the display substrate also includes a base substrate and a pixel defining layer, the pixel defining layer includes a plurality of pixel openings, the plurality of pixel openings respectively define the effective light-emitting areas of the corresponding plurality of sub-pixels, and the plurality of pixel openings are configured to expose the first electrode of the light-emitting element so that the first electrode contacts the subsequently formed light-emitting functional layer. A driving structure layer of the pixel circuit is also provided between the pixel defining layer and the base substrate. The driving structure layer includes a plurality of pixel circuits, each pixel circuit includes a plurality of transistors and at least one storage capacitor. For example, the pixel circuit can adopt a design such as 2T1C, 3T1C, 7T1C or 8T1C. The structure of the pixel circuit can refer to the conventional structural design and will not be repeated here.

[0106] For example, in the display substrate provided in the embodiment of the present disclosure, a planarization layer is further provided between the driving structure layer and the first electrode. An encapsulation layer is further provided on the side of the light-emitting element away from the base substrate, and the encapsulation layer may include a first encapsulation layer, a second encapsulation layer, and a third encapsulation layer arranged in a stacked manner. The first encapsulation layer is made of an inorganic material and covers the second electrode in the display area. The second encapsulation layer is made of an organic material. The third encapsulation layer is made of an inorganic material and covers the first encapsulation layer and the second encapsulation layer. However, this embodiment is not limited to this. For example, the encapsulation layer may also adopt a five-layer structure of inorganic / organic / inorganic / organic / inorganic.

[0107] For example, the display substrate can be applied to a display device, which can be a display device such as an organic light-emitting diode display device, as well as any product or component with a display function, such as a television, digital camera, mobile phone, watch, tablet computer, laptop computer, navigator, etc. that includes the display device. This embodiment is not limited to this.

[0108] The light-emitting element and display substrate provided by at least one embodiment of the present disclosure have at least the following beneficial technical effects: the light-emitting functional layer in the light-emitting element provided by at least one embodiment of the present disclosure includes a first organic layer, a first light-emitting layer, a second organic layer, a second light-emitting layer, a spacer layer, a third light-emitting layer and a second organic layer stacked in sequence in a first direction, the material of the second light-emitting layer includes a first electron blocking material and a light-emitting material doped in the first electron blocking material, the light-emitting material includes at least one of a platinum complex and an iridium complex, and the material of the spacer layer includes the second electron blocking material. That is, the embodiment of the present disclosure eliminates the phenomenon of exciton quenching due to excessive exciton concentration at the interface of the second light-emitting layer, thereby enabling the light-emitting element to emit light in the middle area of ​​the second light-emitting layer, thereby improving the luminous efficiency of the light-emitting element and extending the service life of the display substrate.

[0109] There are a few points to note:

[0110] (1) The drawings of the embodiments of the present disclosure only relate to the structures related to the embodiments of the present disclosure. Other structures may refer to conventional designs.

[0111] (2) For the sake of clarity, in the drawings used to describe the embodiments of the present disclosure, the thickness of layers or regions is exaggerated or reduced, that is, these drawings are not drawn according to the actual scale.

[0112] (3) In the absence of conflict, the embodiments of the present disclosure and the features therein may be combined with each other to form new embodiments.

[0113] The above description is only a specific embodiment of the present disclosure, but the protection scope of the present disclosure is not limited thereto. The protection scope of the present disclosure shall be based on the protection scope of the claims.

Claims

1. A light-emitting element, comprising: A first electrode, a light-emitting functional layer, and a second electrode are sequentially stacked in a first direction, wherein: The light-emitting functional layer includes a first organic layer, a first light-emitting layer, a second organic layer, a second light-emitting layer, a spacer layer, a third light-emitting layer and a third organic layer sequentially stacked in the first direction; The material of the second light-emitting layer includes a first electron blocking material and a light-emitting material doped in the first electron blocking material, wherein the light-emitting material includes at least one of a platinum complex and an iridium complex; The material of the spacer layer includes a second electron blocking material.

2. The light-emitting element according to claim 1, wherein The first electron blocking material and the second electron blocking material are the same.

3. The light-emitting element according to claim 1 or 2, wherein The spacer layer is sandwiched between the second light-emitting layer and the third light-emitting layer, and is in direct contact with both the second light-emitting layer and the third light-emitting layer.

4. The light-emitting element according to any one of claims 1 to 3, wherein The first organic layer includes a hole injection layer, a first hole transport layer and a first electron blocking layer stacked in sequence; The second organic layer includes a first hole blocking layer, a first electron transport layer, a charge generating layer and a second hole transport layer stacked in sequence; The third organic layer includes a second hole blocking layer and a second electron transport layer stacked in sequence.

5. The light-emitting element according to claim 4, wherein The first light-emitting layer is disposed on a surface of the first electron blocking layer away from the hole injection layer and is in direct contact with the first electron blocking layer; The first hole blocking layer is disposed on a surface of the first light-emitting layer away from the hole injection layer and is in direct contact with the first light-emitting layer; The second hole transport layer is disposed on a surface of the second light-emitting layer close to the hole injection layer and is in direct contact with the second light-emitting layer; The second hole blocking layer is disposed on a surface of the third light-emitting layer away from the hole injection layer and is in direct contact with the third light-emitting layer.

6. The light-emitting element according to any one of claims 1 to 5, wherein The light-emitting functional layer further includes an electron injection layer, which is disposed on a side of the third organic layer away from the hole injection layer.

7. The light-emitting element according to any one of claims 1 to 6, wherein The platinum complex includes octaethylporphyrin platinum; The iridium complex includes at least one of bis(1-phenylisoquinolinato)(acetylacetonate)iridium and bis(2-(2'-benzothienyl)pyridine-N,C3')(acetylacetonate)iridium.

8. The light-emitting element according to claim 4, wherein The material of the hole injection layer includes metal oxide, or a hole transport material doped with a p-type dopant of a strong electron-withdrawing system.

9. The light-emitting element according to claim 8, wherein The metal oxide includes at least one of molybdenum oxide, titanium oxide, vanadium oxide, rhenium oxide, ruthenium oxide, chromium oxide, zirconium oxide, hafnium oxide, tantalum oxide, silver oxide, tungsten oxide and manganese oxide; The hole transport material includes at least one of hexacyanohexaazatriphenylene, 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane, and 1,2,3-tris[(cyano)(4-cyano-2,3,5,6-tetrafluorophenyl)methylene]cyclopropane.

10. The light-emitting element according to claim 4, wherein The charge generation layer includes a hole generation layer, and materials of the first hole transport layer, the first electron blocking layer, the second hole transport layer, and the hole generation layer all include at least one of aromatic amines, dimethylfluorene, and carbazoles. The light-emitting element according to claim 10 , wherein The materials of the first hole transport layer, the first electron blocking layer, the second hole transport layer and the hole generating layer all include at least one of 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl, N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine, 4-phenyl-4'-(9-phenylfluorene-9-yl)triphenylamine, 4,4'-bis[N-(9,9-dimethylfluorene-2-yl)-N-phenylamino]biphenyl, 4,4'-di(9-carbazolyl)biphenyl and 9-phenyl-3-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole.

12. The light-emitting element according to claim 10, wherein The charge generation layer also includes an electron generation layer, and the materials of the first hole blocking layer, the second hole blocking layer, the first electron transport layer, the second electron transport layer and the electron generation layer all include at least one of 2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole, 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene, 3-(4-tert-butylphenyl)-4-phenyl-5-(4-biphenyl)-1,2,4-triazole, 3-(4-tert-butylphenyl)-4-(4-ethylphenyl)-5-(4-biphenyl)-1,2,4-triazole, bathophenanthroline, 4-bromo-3-cyanopyridine and 4,4'-bis(5-methylbenzoxazol-2-yl)stilbene.

13. The light-emitting element according to claim 1 or 2, wherein The first electron blocking material and the second electron blocking material each include at least one of 4-(dicyanomethylene)-2-methyl-6-(4-dimethylaminophenylvinyl)-4H-pyran and 4-(dicyanomethylene)-2-tert-butyl-6-(1,1,7,7-tetramethyljulonitrile-9-enyl)-4H-pyran.

14. The light-emitting element according to claim 6, wherein The material of the electron injection layer includes at least one of lithium fluoride, ytterbium, magnesium and calcium metal elements, and oxides of ytterbium, magnesium and calcium.

15. The light-emitting element according to any one of claims 1 to 14, wherein The material of the third light-emitting layer includes a third electron blocking material and the light-emitting material doped in the third electron blocking material. The mass percentage of the light-emitting material doped in the second light-emitting layer is less than half of the mass percentage of the light-emitting material doped in the third light-emitting layer.

16. The light-emitting element according to claim 15, wherein The mass percentage of the luminescent material doped in the second luminescent layer is 0.4% to 1%, and the mass percentage of the luminescent material doped in the third luminescent layer is 1.5% to 2.2%.

17. The light-emitting element according to any one of claims 1 to 16, wherein In the first direction, the thickness of the spacer layer is less than or equal to half the thickness of the third light-emitting layer, and the thickness of the second light-emitting layer is less than or equal to the thickness of the third light-emitting layer.

18. The light-emitting element according to any one of claims 1 to 17, wherein In the first direction, a thickness of the third organic layer is less than or equal to a thickness of the first organic layer.

19. The light-emitting element according to any one of claims 1 to 18, wherein The thickness of the first light-emitting layer is less than or equal to the thickness of the thickest layer among the sublayers of the first organic layer and the sublayers of the third organic layer.

20. The light-emitting element according to any one of claims 1 to 19, wherein The light emitting element is a red light emitting element.

21. A display substrate comprising the light-emitting element according to any one of claims 1 to 20.

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