Display panel and display apparatus

Abstract

The present application relates to a display panel and a display apparatus. The display panel comprises a light-emitting structure, the light-emitting structure comprising a first electrode, a first light-emitting unit and a second electrode; the first light-emitting unit is arranged on one side of the first electrode, and the second electrode is arranged on the side of the first light-emitting unit facing away from the first electrode; the first light-emitting unit comprises a first hole transport layer, a first electron transport layer, a first light-emitting layer located between the first hole transport layer and the first electron transport layer, and a first common electron blocking layer located between the first hole transport layer and the first light-emitting layer; the first light-emitting layer comprises three sub-light-emitting layers, at least one sub-light-emitting layer comprising a material having TADF characteristics. In the present application, the first common electron blocking layer is provided, such that there is no need to separately provide an electron blocking layer for the sub-light-emitting layer doped with the material having TADF characteristics, reducing the number of evaporation chambers and fine metal thin films, thus reducing the manufacturing difficulty and costs of the process.

Description

Display panel and display device Technical Field

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

[0002] OLED (Organic Light Emitting Diode) display devices have become a highly competitive and promising type of display device due to their advantages such as all-solid-state structure, self-luminescence, fast response speed, high brightness, full viewing angle, and flexible display.

[0003] OLED displays often utilize sensitized fluorescence technology, particularly TADF (Thermal Activated Delayed Fluorescence). This technology offers high efficiency while also combining the high color purity of fluorescent emitters. This technology offers advantages over traditional fluorescent and phosphorescent technologies in the display field. However, the device structure of TADF systems is currently more complex than that of conventional phosphorescent devices, requiring additional evaporation equipment, which increases the manufacturing process complexity and cost.

[0004] Summary of the Invention

[0005] The present application provides a display panel and a display device to address the deficiencies in the related art.

[0006] According to a first aspect of an embodiment of the present application, a display panel is provided, which includes a light-emitting structure, wherein the light-emitting structure includes: a first electrode, a first light-emitting unit and a second electrode; the first light-emitting unit is arranged on one side of the first electrode, and the second electrode is arranged on a side of the first light-emitting unit facing away from the first electrode; the first light-emitting unit includes a first hole transport layer, a first electron transport layer, a first light-emitting layer located between the first hole transport layer and the first electron transport layer, and a first common electron blocking layer located between the first hole transport layer and the first light-emitting layer; the first light-emitting layer includes three sub-light-emitting layers, and at least one of the sub-light-emitting layers contains a material with thermosensitive properties.

[0007] Furthermore, the three sub-light-emitting layers are spaced apart and disposed between the first common electron blocking layer and the first electron transport layer; and the area of ​​the first common electron blocking layer is greater than or equal to the sum of the areas of the three sub-light-emitting layers.

[0008] Furthermore, the first light-emitting layer further includes a sub-electron blocking layer; the number of the sub-electron blocking layers is the same as the number of the sub-light-emitting layer that does not include the material having thermally activated delayed fluorescence characteristics.

[0009] Furthermore, the area of ​​the sub-electron blocking layer is greater than or equal to the area of ​​the sub-light-emitting layer that does not contain the material having thermally activated delayed fluorescence properties; the sub-electron blocking layer is arranged one-to-one below the sub-light-emitting layer that does not contain the material having thermally activated delayed fluorescence properties and is located between the sub-light-emitting layer that does not contain the material having thermally activated delayed fluorescence properties and the first common electron blocking layer.

[0010] Furthermore, the first light-emitting layer also includes an auxiliary light-emitting layer, the number of the auxiliary light-emitting layers is the same as the number of the sub-light-emitting layers containing the material having thermally activated delayed fluorescence properties, and the area of ​​the auxiliary light-emitting layer is greater than or equal to the area of ​​the sub-light-emitting layer containing the material having thermally activated delayed fluorescence properties; the auxiliary light-emitting layers are arranged one-to-one below the sub-light-emitting layers containing the material having thermally activated delayed fluorescence properties and are located between the sub-light-emitting layers containing the material having thermally activated delayed fluorescence properties and the first common electron blocking layer.

[0011] Furthermore, the thickness of the auxiliary light-emitting layer is smaller than the thickness of the corresponding sub-light-emitting layer; the auxiliary light-emitting layer comprises a light-emitting main material and a material having thermally activated delayed fluorescence properties, and the light-emitting main material and the material having thermally activated delayed fluorescence properties are the same as the material of the sub-light-emitting layer corresponding to the auxiliary light-emitting layer.

[0012] Furthermore, the sub-light-emitting layer includes a red light-emitting layer, a green light-emitting layer and a blue light-emitting layer, and only the green light-emitting layer contains a material with thermally activated delayed fluorescence characteristics; the sub-electron blocking layer includes a red light-emitting electron blocking layer and a blue light-emitting electron blocking layer, and the red light-emitting layer and the blue light-emitting layer are respectively arranged below the red light-emitting layer and the blue light-emitting layer; the auxiliary light-emitting layer includes a green light-assisted light-emitting layer; the green light-assisted light-emitting layer is arranged below the green light-emitting layer; the first excited triplet energy level value of the first common electron blocking layer is greater than or equal to the first excited triplet energy level value of the thermally activated delayed fluorescence characteristic material contained in the green light-emitting layer.

[0013] Furthermore, the first common electron blocking layer is made of hole-type carbazole or aromatic amine derivatives, and the thickness of the first common electron blocking layer is less than or equal to 10 nm.

[0014] Furthermore, the highest occupied molecular orbital value of the blue photon electron blocking layer is greater than the highest occupied molecular orbital value of the blue light emitting layer, and less than the highest occupied molecular orbital value of the first hole transport layer; the singlet excited state value of the blue light electron blocking layer is greater than the singlet excited state value of the blue light emitting layer.

[0015] Furthermore, the absolute value of the highest occupied molecular orbital value of the first common electron blocking layer and the highest occupied molecular orbital value of the first hole transport layer, the absolute value of the highest occupied molecular orbital value of the first common electron blocking layer and the highest occupied molecular orbital value of the blue light electron blocking layer, and the absolute value of the highest occupied molecular orbital value of the first common electron blocking layer and the highest occupied molecular orbital value of the red light electron blocking layer are all less than or equal to 0.25 eV.

[0016] Furthermore, the light-emitting structure further includes a first hole blocking layer; the first hole blocking layer is disposed on a side of the first light-emitting unit facing away from the first electrode and is located between the first light-emitting unit and the second electrode.

[0017] Furthermore, the light-emitting structure also includes a charge generation structure and a second light-emitting unit; the charge generation structure is arranged on the side of the first light-emitting unit facing away from the first electrode; the second light-emitting unit is arranged on the side of the charge generation structure facing away from the first electrode.

[0018] Furthermore, the second light-emitting unit includes a second hole transport layer, a second light-emitting layer located between the second hole transport layer and the first electron transport layer, and a second common electron blocking layer located between the second hole transport layer and the second light-emitting layer; the second light-emitting layer includes three sub-light-emitting layers, at least one of the sub-light-emitting layers contains a material having thermally activated delayed fluorescence properties.

[0019] Furthermore, the charge generation structure includes an N-type charge generation layer and a P-type charge generation layer; the N-type charge generation layer is arranged on the side of the first light-emitting unit facing away from the first electrode; the P-type charge generation layer is arranged on the side of the N-type charge generation layer facing away from the first electrode.

[0020] Furthermore, the light-emitting structure also includes a hole injection layer and an electron injection layer; the first electrode is an anode, and the second electrode is a cathode; the hole injection layer is arranged between the first hole transport layer and the first electrode; the electron injection layer is arranged between the first electron transport layer and the second electrode.

[0021] According to a second aspect of the embodiments of the present application, a display device is provided, comprising the above-mentioned display panel.

[0022] According to the above embodiments, the present application sets a first common electron blocking layer, and there is no need to set a separate electron blocking layer for the sub-light-emitting layer containing the thermally activated delayed fluorescence material. This can reduce the number of evaporation chambers and fine metal films, and reduce the difficulty and cost of process manufacturing.

[0023] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0025] FIG1 is a schematic diagram of a light-emitting structure according to an embodiment of the present application.

[0026] FIG. 2 is a schematic diagram of a second embodiment of the light emitting structure shown in FIG. 1 .

[0027] FIG3 is a schematic diagram of a third embodiment of the light emitting structure shown in FIG1 .

[0028] FIG4 is a schematic diagram of the light-emitting structure shown in FIG1 with multiple light-emitting units connected in series.

[0029] FIG5 is a schematic diagram of the light-emitting structure shown in FIG4 in which only the red light-emitting layer is TADF-doped.

[0030] FIG6 is a schematic diagram of the light-emitting structure shown in FIG4 in which both the red light-emitting layer and the green light-emitting layer are TADF-doped.

[0031] FIG. 7 is a schematic diagram of the light-emitting structure shown in FIG. 4 with an auxiliary light-emitting layer added.

[0032] FIG8 is a schematic diagram of the light-emitting structure shown in FIG5 with an auxiliary light-emitting layer added.

[0033] FIG. 9 is a schematic diagram of the light-emitting structure shown in FIG. 6 with an auxiliary light-emitting layer added.

[0034] FIG10 is a schematic diagram of the light-emitting structure shown in FIG4 , in which all sub-light-emitting layers are TADF-doped and an auxiliary light-emitting layer is added.

[0035] FIG. 11 is a schematic diagram of another embodiment of the light emitting structure shown in FIG. 4 .

[0036] Explanation of the accompanying symbols: 1. first electrode; 2. first light-emitting unit; 21. first hole transport layer; 22. first common electron blocking layer; 23. first light-emitting layer; 231. sub-light-emitting layer; 2311. red light-emitting layer; 2312. green light-emitting layer; 2313. blue light-emitting layer; 232. sub-electron blocking layer; 2321. red light-emitting layer; 2321a. first blocking layer; 2321b. second blocking layer; 2322. blue light-emitting layer; 2323. green light-emitting layer; 233. auxiliary light-emitting layer; Light layer; 2331, green light auxiliary light-emitting layer; 2332, red light auxiliary light-emitting layer; 2333, blue light auxiliary light-emitting layer; 24, first hole blocking layer; 25, first electron transport layer; 26, hole injection layer; 27, electron injection layer; 3, second electrode; 4, encapsulation layer; 5, charge generation structure; 51, N-type charge generation layer; 52, P-type charge generation layer; 6, second light-emitting unit; 61, second hole transport layer; 62, second common electron blocking layer; 63, second light-emitting layer; 64, second hole blocking layer. DETAILED DESCRIPTION

[0037] Exemplary embodiments will be described in detail herein, with examples illustrated in the accompanying drawings. In the following description, when referring to the drawings, identical numerals in different figures represent identical or similar elements, unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all embodiments consistent with the present application. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present application, as detailed in the appended claims.

[0038] Referring to Figure 1 , the present application provides a display panel. The display panel includes a light-emitting structure, which comprises a first electrode 1, a first light-emitting unit 2, and a second electrode 3. The first light-emitting unit 2 is disposed on one side of the first electrode 1, and the second electrode 3 is disposed on the side of the first light-emitting unit 2 facing away from the first electrode 1.

[0039] The first electrode 1 can be a cathode or an anode. When the first electrode 1 is an anode, the second electrode 3 is a cathode; conversely, when the first electrode 1 is a cathode, the second electrode 3 is an anode.

[0040] In the embodiment of the present application, preferably, the first electrode 1 is an anode.

[0041] The first electrode 1 is made of an electrode material with a high work function, and can be a transparent oxide ITO (indium tin oxide) or IZO (tin zinc oxide), etc. When the above electrode material is used, the thickness of the first electrode 1 should optionally be greater than 80nm and less than 200nm. At this time, the display panel provided in this application is a bottom emission structure.

[0042] The first electrode 1 may also be a composite electrode formed of a metal and an oxide, such as Ag / ITO, Al / ITO, Ag / ITO, or Al / IZO. In this case, the metal thickness in the composite electrode should be greater than 10 nm and less than 100 nm, and the corresponding oxide layer thickness should be greater than 5 nm and less than 20 nm. In this case, the display panel provided in this application has a top-emitting structure.

[0043] The second electrode 3, thus serving as the cathode, can be made of a metal material with a low work function, such as Al, Ag, or Mg, or an alloy containing such a metal material. When the display panel has a bottom-emitting structure, the thickness of the second electrode 3 is greater than 80 nm to ensure good reflectivity. Preferably, its transmittance for light with a wavelength of 550 nm should be greater than 85%.

[0044] When the display panel is a top-emitting structure, the thickness of the second electrode 3 should be adjusted between greater than 10nm and less than 20nm to ensure its transmittance. Preferably, at this time, its transmittance to light with a wavelength of 550nm should be greater than 45%, and an optical capping layer (CPL, Capping Layer) should be covered on the metal layer of the second electrode 3 to improve its optical output. Preferably, the material for making the optical capping layer should be formed by evaporation of a small molecule material with a high refractive index. Furthermore, its refractive index at 550nm should be greater than 1.8, and its thickness should be greater than 50nm and less than 100nm.

[0045] As shown in FIG1 , an encapsulation layer 4 is provided above the second electrode 3 to encapsulate the first electrode 1, the second electrode 3, and the first light-emitting unit 2 to prevent damage from the external environment. The encapsulation layer 4 can be encapsulated using UV sealant or thin film encapsulation (TFE).

[0046] The first light-emitting unit 2 includes a hole injection layer 26 , a first hole transport layer 21 , a first light-emitting layer 23 , a first hole blocking layer 24 , a first electron transport layer 25 and an electron injection layer 27 stacked in sequence from bottom to top.

[0047] The first light-emitting layer 23 includes three sub-light-emitting layers 231: a red light-emitting layer 2311, a green light-emitting layer 2312, and a blue light-emitting layer 2313. At least one of the three sub-light-emitting layers 231 comprises a material exhibiting thermally activated delayed fluorescence. A first common electron-blocking layer 22 is also disposed between the first hole-transporting layer 21 and the first light-emitting layer 23.

[0048] The three sub-light-emitting layers 231 are spaced apart and disposed between the first common electron blocking layer 22 and the first electron transport layer 25. The area of ​​the first common electron blocking layer 22 is greater than or equal to the sum of the areas of the three sub-light-emitting layers 231. The first light-emitting layer 23 further includes a pixel definition layer (PDL) (not shown), which is disposed between the three sub-light-emitting layers 231. The three sub-light-emitting layers 231 are separated by the pixel definition layer. Due to process limitations, in an embodiment, the edge regions of the three sub-light-emitting layers 231 may partially overlap. Specifically, the red light-emitting layer 2311 may overlap with the adjacent green light-emitting layer 2312 or blue light-emitting layer 2313 in the edge region.

[0049] An electron blocking layer (EBL) is a layered material used in semiconductor devices. Its primary function is to block the unnecessary transmission or leakage of electrons within the device, effectively preventing electrons from entering irrelevant layers from the electron transport layer or electrode. This ensures the accuracy and stability of electron injection, helping to improve the device's electron transport efficiency and luminescence. The EBL provides a certain energy band barrier, effectively reducing or blocking leakage current within the device. It can also be used to optimize interface matching between different materials, bridging energy level differences between interfaces and improving electron transport efficiency between materials, thereby reducing non-ideal phenomena such as band bending and reflection.

[0050] Therefore, conventional solutions generally place a corresponding electron-blocking layer under each sub-luminescent layer 231. The area of ​​this electron-blocking layer should be greater than or equal to the area of ​​its corresponding sub-luminescent layer 231, and the thickness of the red electron-blocking layer should be greater than that of the blue electron-blocking layer, which in turn should be greater than that of the green electron-blocking layer. However, conventional electron-blocking layers require evaporation using a fine metal mask, making the manufacturing process difficult and costly.

[0051] Based on the traditional solution, the present application sets a first common electron blocking layer 22, and the three sub-light-emitting layers 231 are all located between the first common electron blocking layer 22 and the first electron transport layer 25. There is no need to set an electron blocking layer separately for the sub-light-emitting layer 231 containing thermally activated delayed fluorescence material. The number of electron blocking layers can be reduced accordingly, thereby reducing the number of evaporation chambers and fine metal films, and reducing the difficulty and cost of process manufacturing.

[0052] 1 to 3 , at least one of the sub-light-emitting layers 231 mentioned in the present application contains a material having thermally activated delayed fluorescence properties, which means that one sub-light-emitting layer 231 may be doped with thermally activated delayed fluorescence, or two or even all sub-light-emitting layers 231 may be doped with thermally activated delayed fluorescence.

[0053] When only one sub-light-emitting layer 231 is subjected to thermally activated delayed fluorescence doping, as shown in FIG1 , taking the thermally activated delayed fluorescence doping of the green light-emitting layer 2312 as an example, the green light-emitting layer 2312 does not need to be provided with a corresponding separate electron blocking layer; the electron blocking effect can be achieved solely through the first common electron blocking layer 22. In this case, the red light-emitting layer 2311 and the blue light-emitting layer 2313 are each provided with a corresponding red light electron blocking layer 2321 and a blue light electron blocking layer 2322 below them. Because the red light-emitting layer 2311 and the blue light-emitting layer 2313 are both located above the first common electron blocking layer 22, the first common electron blocking layer 22 can also enhance the effects of the red light electron blocking layer 2321 and the blue light electron blocking layer 2322, respectively.

[0054] This embodiment is not limited to the thermally activated delayed fluorescence doping of the green light emitting layer 2312 , and the red light emitting layer 2311 and the blue light emitting layer 2313 can also be used as embodiments, which will not be repeated here.

[0055] When thermally activated delayed fluorescence doping is performed on the two sub-light-emitting layers 231, as shown in FIG2 , taking the thermally activated delayed fluorescence doping of the red light-emitting layer 2311 and the green light-emitting layer 2312 as an example, the red light-emitting layer 2311 and the green light-emitting layer 2312 do not need to be provided with corresponding separate electron blocking layers. The electron blocking effect can be achieved solely through the first common electron blocking layer 22. In this case, a corresponding blue light electron blocking layer 2322 is provided below the blue light-emitting layer 2313.

[0056] The thermally activated delayed fluorescence doping of the two sub-light-emitting layers 231 is not limited to the red light-emitting layer 2311 and the green light-emitting layer 2312. It is foreseeable that the red light-emitting layer 2311 and the blue light-emitting layer 2313, and the green light-emitting layer 2312 and the blue light-emitting layer 2313 can also be used as an embodiment, which will not be repeated here.

[0057] When the three sub-light emitting layers 231 are doped with thermally activated delayed fluorescence, as shown in FIG. 3 , the electron blocking effect for all the sub-light emitting layers 231 can be achieved only by the first common electron blocking layer 22 .

[0058] Specifically, referring to Figure 1, taking the thermally activated delayed fluorescence doping of a single green light-emitting layer 2312 as an example, in this embodiment, the hole injection layer 26 can be made of an injection material such as CuPc, HATCN, or MnO3, or can be formed by p-type doping in a hole transport material. When a hole transport material is used for p-type doping, the p-type dopant can optionally be an inorganic oxide material or an organic radialene material. The thickness of the hole injection layer 26 should be greater than 1 nm and less than 30 nm. The hole injection layer 26 can be formed by multi-source co-evaporation.

[0059] The first hole transport layer 21 can be formed of a material having good hole transport properties, including carbazole and its derivatives with high hole mobility. The thickness of the first hole transport layer 21 should be greater than 1 nm and less than 200 nm.

[0060] The electron injection layer 27 can be formed by evaporation using a low work function metal material such as Li, Ca, Yb, or a metal salt such as LiF or LiQ3. The thickness of the electron injection layer 27 should be greater than 0.5 nm and less than 2 nm. In the embodiment of the present application, the electron injection layer 27 is formed by evaporation using a Yb metal material.

[0061] The first common electron blocking layer 22 has a high first excited triplet energy level, at least not lower than the first excited triplet energy level of the thermally activated delayed fluorescent material in the green light-emitting layer 2312. This serves to prevent exciton leakage from the light-emitting layer, thereby improving efficiency and stability. The material of the first common electron blocking layer 22 can be selected from hole-type carbazole and aromatic amine derivatives, and its thickness does not exceed 10 nm.

[0062] The blue electron blocking layer 2322 is used to reduce the barrier for hole transport from the adjacent first hole transport layer 21 to the blue light-emitting layer 2313. Therefore, the highest occupied molecular orbital energy level of the material in this layer should be between the highest occupied molecular orbital energy level of the adjacent first hole transport layer 21 and the highest occupied molecular orbital energy level of the host material of the blue light-emitting layer 2313. Furthermore, the blue electron blocking layer 2322 also has an exciton-blocking effect, ensuring that the singlet first excited state energy of the material in this layer is greater than the singlet first excited state energy of the material in the blue light-emitting layer 2313. Optionally, this layer can be made of carbazole and its derivatives.

[0063] The red electron blocking layer 2321 is used to reduce the hole transmission barrier from the adjacent first hole transport layer 21 to the red light emitting layer 2311, while ensuring that the excitons in the light emitting layer do not overflow. Optionally, the material of this layer can be carbazole and its derivatives.

[0064] The blue light-emitting layer 2313 comprises at least a host material and a fluorescent guest material. The host material's emission spectrum significantly overlaps with the guest material's absorption spectrum. Under normalized spectral conditions, the overlapping area of ​​the host material accounts for at least 60% of the guest absorption spectrum. Optional host materials include anthracenes, fluorenes, pyrenes, or their derivatives. The guest material can be a pyrene-based organic compound or a boron-containing organic compound. The doping concentration can be adjusted between 0.5% and 5%, and its main emission peak wavelength should be between 450 and 480 nm.

[0065] The green light-emitting layer 2312 includes a hole-type host material, a material having thermally activated delayed fluorescence (TADF) properties, and a fluorescent guest material. The hole-type host material can be a carbazole-based material, the TDF material can be a polycarbazole-based material having a DLA structure, and the fluorescent guest material can be a boron-containing organic compound. The host material has a first excited triplet energy level higher than the first excited triplet energy level of the TDF material. Preferably, the first excited triplet energy level of the hole-type host material is at least 0.1 eV higher than that of the TDF material. The emission spectrum of the TDF material significantly overlaps with the absorption spectrum of the guest material. Optimally, the overlap area of ​​the normalized spectrum of the TDF material should account for at least 60% of the guest absorption spectrum area.

[0066] The red light-emitting layer 2311 comprises at least a P-type host material, an N-type host material, and a luminescent guest material. The N-type host material can be a conventional material or a material exhibiting thermally activated delayed fluorescence. The luminescent guest material can be a phosphorescent material or a boron-containing fluorescent material. The thickness of the red light-emitting layer 2311 can be adjusted between greater than 30 nm and less than 80 nm.

[0067] The thickness of the first hole blocking layer 24 should be greater than 5 nm and less than 30 nm. The first excited triplet energy level of the material in this layer must be greater than the first excited triplet energy level of the material with thermally activated delayed fluorescence in the connected green light-emitting layer 2312. Preferably, the difference should be greater than or equal to 0.2 eV. The absolute value of the highest occupied molecular orbital energy level of the material in the first hole blocking layer 24 must be greater than the absolute value of the highest occupied molecular orbital energy level of the material in all connected sub-light-emitting layers 231. Preferably, it should be greater than 0.2 eV. The absolute value of the lowest unoccupied molecular orbital energy level of the material in the first hole blocking layer 24 must be less than the absolute value of the lowest unoccupied molecular orbital energy level of the material in all connected sub-light-emitting layers 231.

[0068] The electron injection layer 27 can be formed by evaporating a material having excellent electron transport properties, or by doping an electron transport material with LIQ3, Li, Ca, or other materials in a certain ratio. The absolute value of the lowest unoccupied molecular orbital energy level of all materials in the electron injection layer 27 must be greater than the absolute value of the lowest unoccupied molecular orbital energy level of the material of the first hole blocking layer 24 to which it is connected.

[0069] It is worth mentioning that the energy levels and mobilities of the first common electron blocking layer 22 and the adjacent film layers should satisfy the following relationship:

[0070] |HOMO(GEBL)-HOMO(HTL)|≤0.25eV, preferably ≤0.15eV

[0071] |HOMO(G EBL)-HOMO(B EBL)|≤0.25eV, preferably ≤0.15eV

[0072] ∣HOMO(G EBL)-HOMO(R EBL)∣≤0.25eV

[0073] Among them, HOMO(G EBL) refers to the HOMO energy level value of the first common electron blocking layer 22, HOMO(HTL) refers to the HOMO energy level value of the first hole transporting layer 21 (HBL Hole Transporting Layer), HOMO(B EBL) refers to the HOMO energy level value of the blue electron blocking layer 2322, and HOMO(R EBL) refers to the HOMO energy level value of the red electron blocking layer 2321.

[0074] At this time, it is ensured that holes can be smoothly injected into the red light emitting layer 2311 and the blue light emitting layer 2313;

[0075] Preferably, since the turn-on voltage of the red light emitting layer 2311 is lower than that of the blue light emitting layer 2313, the potential barrier of the red light emitting layer 2311 should be increased to increase the turn-on voltage of the red light emitting layer 2311 and reduce the voltage difference between the red light emitting layer 2311 and the blue light emitting layer 2313 to facilitate better display of the image. Therefore, |HOMO(G EBL)-HOMO(R EBL)|≥|HOMO(G EBL)-HOMO (B EBL)| should be satisfied;

[0076] Preferably, since the turn-on voltage of the red light emitting layer 2311 is lower than that of the blue light emitting layer 2313, and due to the presence of the first common electron blocking layer 22, in order to prevent the crosstalk problem caused by lateral leakage, the following hole mobility needs to be met:

[0077] 10-5<hole mobility (GEBL) / hole mobility (HTL)<10-3

[0078] 10-4<Hole mobility (G EBL) / Hole mobility (R EBL)<10-2

[0079] 10-2<hole mobility (G EBL) / hole mobility (B EBL)<10

[0080] 10-3<hole mobility (B EBL) / hole mobility (R EBL)<10-1.

[0081] Among them, the hole mobility (GEBL) refers to the hole mobility of the first common electron blocking layer 22, the hole mobility (HTL) refers to the hole mobility of the first hole transporting layer 21 (HBL Hole Transporting Layer), the hole mobility (BEBL) refers to the hole mobility of the blue electron blocking layer 2322, and the hole mobility (R EBL) refers to the hole mobility of the red electron blocking layer 2321.

[0082] The light-emitting structure in the above embodiment includes only one light-emitting unit. In another embodiment, as shown in Figures 4 to 11, the light-emitting structure provided by the present application further includes a charge generation structure 5 and a second light-emitting unit 6. The charge generation structure 5 is disposed on the side of the first light-emitting unit 2 facing away from the first electrode 1, and the second light-emitting unit 6 is disposed on the side of the charge generation structure 5 facing away from the first electrode 1.

[0083] In this embodiment, a light-emitting structure is formed by connecting a charge generation structure 5 in series between two light-emitting units. Alternatively, a light-emitting structure may be formed by connecting three or more light-emitting units in series with a charge generation structure 5 between them. This embodiment is not limited to this.

[0084] The second light-emitting unit 6 includes a second hole transport layer 61, a second light-emitting layer 63 located between the second hole transport layer 61 and the first electron transport layer 25, and a second common electron blocking layer 62 located between the second hole transport layer 61 and the second light-emitting layer 63. The second light-emitting layer 63 includes three sub-light-emitting layers 231, at least one of which includes a material having thermally activated delayed fluorescence properties.

[0085] The charge generation structure 5 includes an N-type charge generation layer 51 and a P-type charge generation layer 52. The N-type charge generation layer 51 is disposed on the side of the first light-emitting unit 2 facing away from the first electrode 1, and the P-type charge generation layer 52 is disposed on the side of the N-type charge generation layer 51 facing away from the first electrode 1.

[0086] The N-type charge generation layer 51 can be formed by doping an electron transport material with an active metal having a low work function, such as Li, Ca, or Yb.

[0087] The P-type charge generation layer 52 can be formed by doping a hole transport material with a P-type dopant such as molybdenum oxide. The proportion of the P-type dopant in the P-type charge generation layer 52 must be higher than that in the hole injection layer 26 to facilitate charge generation.

[0088] In this embodiment, the structure of the second light-emitting unit 6 is the same as that of the first light-emitting unit 2 , and the materials constituting each film layer of the second light-emitting unit 6 may be consistent with or inconsistent with the materials of the first light-emitting unit 2 .

[0089] 7 to 10 , the first light-emitting layer 23 further includes an auxiliary light-emitting layer 233. The auxiliary light-emitting layer 233 is disposed between the sub-light-emitting layer 231 doped with thermally activated delayed fluorescence and the first common electron blocking layer 22. In the embodiment shown in FIG7 , a green auxiliary light-emitting layer 2331 is disposed below the green light-emitting layer 2312.

[0090] The thickness of the green auxiliary light-emitting layer 2331 is smaller than that of the green light-emitting layer 2312. The green auxiliary light-emitting layer 2331 includes a luminescent host material and a material having thermally activated delayed fluorescence properties, and the luminescent host material and the material having thermally activated delayed fluorescence properties are the same as those of the green light-emitting layer 2312.

[0091] As shown in FIG. 8 , in this embodiment, the red light emitting layer 2311 is doped with thermally activated delayed fluorescence, and thus a red auxiliary light emitting layer 2332 is provided under the red light emitting layer 2311 .

[0092] The thickness of the red auxiliary light-emitting layer 2332 is less than that of the red light-emitting layer 2311. The red auxiliary light-emitting layer 2332 includes a luminescent host material and a material having thermally activated delayed fluorescence properties, and the luminescent host material and the material having thermally activated delayed fluorescence properties are the same as those of the red light-emitting layer 2311.

[0093] As shown in FIG9 , in this embodiment, the red light emitting layer 2311 and the green light emitting layer 2312 are both thermally activated delayed fluorescence doped, so a red auxiliary light emitting layer 2332 and a green auxiliary light emitting layer 2331 are respectively disposed under the red light emitting layer 2311 and the green light emitting layer 2312 .

[0094] The properties of the red auxiliary light emitting layer 2332 and the green auxiliary light emitting layer 2331 have been described in the embodiment shown in FIG. 8 and will not be repeated here.

[0095] As shown in FIG10 , in this embodiment, all sub-light emitting layers 231 are doped with thermally activated delayed fluorescence, and thus auxiliary light emitting layers 233 are provided under each sub-light emitting layer 231. In this embodiment, the auxiliary light emitting layers 233 include a green auxiliary light emitting layer 2331, a red auxiliary light emitting layer 2332, and a blue auxiliary light emitting layer 2333.

[0096] The red auxiliary light-emitting layer 2332 and the green auxiliary light-emitting layer 2331 have been described in the above embodiments and will not be repeated here. Regarding the blue auxiliary light-emitting layer 2333, its thickness is less than that of the blue light-emitting layer 2313. The blue auxiliary light-emitting layer 2333 comprises a luminescent host material and a material having thermally activated delayed fluorescence properties. The luminescent host material and the material having thermally activated delayed fluorescence properties are the same as those of the blue light-emitting layer 2313.

[0097] As shown in FIG11 , in this embodiment, the red electron blocking layer 2321 includes a first blocking layer 2321a and a second blocking layer 2321b. The stacking of the first blocking layer 2321a and the second blocking layer 2321b to form the red electron blocking layer 2321 effectively increases the voltage of the red light-emitting layer 2311, reduces the voltage difference between the red light-emitting layer 2311 and the blue light-emitting layer 2313, improves crosstalk, improves the device efficiency of the red light-emitting layer 2311, and reduces the power consumption of the entire device.

[0098] The specific structure and device characteristics of the embodiment of the present application are as follows:

[0099] Table 1

[0100] Example 1:

[0101] From bottom to top:

[0102] First electrode 1: metal Ag (thickness 100nm) / ITO layer (thickness 8nm) / ;

[0103] First hole transport layer 21: HT (hole transport): p-type (thickness 10 nm, doping concentration 3%) / HT (hole transport) (B color adjustment);

[0104] First light-emitting layer 23: Red electron blocking layer 2321 / red light-emitting layer 2311: RH (Red Host) + RD (Red Dopant) (doping 3%); Green electron blocking layer 2323 / green light-emitting layer 2312: GH (Green Host) + G-TADF + GD (green dopant) (ratio of 69%:30%:1.0%); Blue electron blocking layer 2322 (5 nm thick) / blue light-emitting layer 2313: BH (Blue Host) + BD (Blue Dopant) (doping 3%);

[0105] First hole blocking layer 24: HB (5 nm);

[0106] Charge generation structure 5: N-type charge generation layer 51: n-CG: Yb (1%) / P-type charge generation layer 52: HT: p-type (thickness 10 nm, doping concentration 10%);

[0107] a second hole transport layer 61;

[0108] Second light-emitting layer 63: Red electron blocking layer 2321 / red light-emitting layer 2311: RH (Red Host) + RD (Red Dopant) (doping 3%); Green electron blocking layer 2323 / green light-emitting layer 2312: GH (Green Host) + G-TADF + GD (green dopant) (ratio of 69%:30%:1.0%); Blue electron blocking layer 2322 (5 nm thick) / blue light-emitting layer 2313: BH (Blue Host) + BD (Blue Dopant) (doping 3%);

[0109] Second hole blocking layer 64: HB (Hole Blocking) (thickness 5 nm);

[0110] First electron transport layer 25: LiQ (liquid Li) (thickness 35 nm, ratio of liquid Li to liquid lead is 50%:50%);

[0111] Electron injection layer 27: EIL (Electron Injecting Layer) (thickness 1 nm);

[0112] Second electrode 3: Mg and Ag alloy (thickness 15 nm) + optical cover layer CPL (capping layer).

[0113] This embodiment 1 is a conventional method in which a corresponding electron blocking layer is disposed under each sub-light-emitting layer 231 , and serves as a comparative example.

[0114] Example 2:

[0115] First electrode 1: metal Ag (thickness 100nm) / ITO layer (thickness 8nm) / ;

[0116] First hole transport layer 21: HT (hole transport): p-type (thickness 10 nm, doping concentration 3%) / HT (hole transport) (B color adjustment);

[0117] a first common electron blocking layer 22 (5 nm thick);

[0118] First light-emitting layer 23: Red electron blocking layer 2321 / red light-emitting layer 2311: RH (Red Host) + RD (Red Dopant) (doping 3%); Green light-emitting layer 2312: GH (Green Host) + G-TADF + GD (green dopant) (ratio of 69%:30%:1.0%); Blue electron blocking layer 2322 (thickness 5nm) / blue light-emitting layer 2313: BH (Blue Host) + BD (Blue Dopant) (doping 3%);

[0119] First hole blocking layer 24: HB (5 nm);

[0120] Charge generation structure 5: N-type charge generation layer 51: n-CG: Yb (1%) / P-type charge generation layer 52: HT: p-type (thickness 10 nm, doping concentration 10%);

[0121] a second hole transport layer 61;

[0122] A second common electron blocking layer 62 (5 nm thick);

[0123] Second light-emitting layer 63: red electron blocking layer 2321 / red light-emitting layer 2311: RH (Red Host) + RD (Red Dopant) (doping 3%); green light-emitting layer 2312: GH (Green Host) + G-TADF + GD (green dopant) (ratio of 69%:30%:1.0%); blue electron blocking layer 2322 (thickness 5 nm) / blue light-emitting layer 2313: BH (Blue Host) + BD (Blue Dopant) (doping 3%);

[0124] Second hole blocking layer 64: HB (Hole Blocking) (thickness 5 nm);

[0125] First electron transport layer 25: LiQ (liquid Li) (thickness 35 nm, ratio of liquid Li to liquid lead is 50%:50%);

[0126] Electron injection layer 27: EIL (Electron Injecting Layer) (thickness 1 nm);

[0127] Second electrode 3: Mg and Ag alloy (thickness 15 nm) + optical cover layer CPL (capping layer).

[0128] As shown in Table 1 and FIG4 , this embodiment adds a first common electron blocking layer 22 , and its device performance is substantially equivalent to that of embodiment 1. However, compared to embodiment 1, embodiment 2 reduces one chamber and a fine metal mask, effectively reducing the process flow and lowering costs.

[0129] Example 3:

[0130] First electrode 1: metal Ag (thickness 100nm) / ITO layer (thickness 8nm) / ;

[0131] First hole transport layer 21: HT (hole transport): p-type (thickness 10 nm, doping concentration 3%) / HT (hole transport) (B color adjustment);

[0132] a first common electron blocking layer 22 (5 nm thick);

[0133] First light-emitting layer 23: red electron blocking layer 2321 / red light-emitting layer 2311: RH (Red Host) + RD (Red Dopant) (doping 3%); green auxiliary light-emitting layer 2331: GH (Green Host) + G-TADF (ratio of 70%:30%) / green light-emitting layer 2312: green light-emitting layer 2312: GH (Green Host) + G-TADF + GD (green dopant) (ratio of 69%:30%:1.0%); blue electron blocking layer 2322 (thickness 5 nm) / blue light-emitting layer 2313: BH (Blue Host) + BD (Blue Dopant) (doping 3%);

[0134] First hole blocking layer 24: HB (5 nm);

[0135] Charge generation structure 5: N-type charge generation layer 51: n-CG: Yb (1%) / P-type charge generation layer 52: HT: p-type (thickness 10 nm, doping concentration 10%);

[0136] a second hole transport layer 61;

[0137] A second common electron blocking layer 62 (5 nm thick);

[0138] Second light-emitting layer 63: red electron blocking layer 2321 / red light-emitting layer 2311: RH (Red Host) + RD (Red Dopant) (doping 3%); green auxiliary light-emitting layer 2331: GH (Green Host) + G-TADF (ratio of 70%:30%) / green light-emitting layer 2312: GH (Green Host) + G-TADF + GD (green dopant) (ratio of 69%:30%:1.0%); blue electron blocking layer 2322 (thickness 5 nm) / blue light-emitting layer 2313: BH (Blue Host) + BD (Blue Dopant) (doping 3%);

[0139] Second hole blocking layer 64: HB (Hole Blocking) (thickness 5 nm);

[0140] First electron transport layer 25: LiQ (liquid Li) (thickness 35 nm, ratio of liquid Li to liquid lead is 50%:50%);

[0141] Electron injection layer 27: EIL (Electron Injecting Layer) (thickness 1 nm);

[0142] Second electrode 3: Mg and Ag alloy (thickness 15 nm) + optical cover layer CPL (capping layer).

[0143] Please refer to Table 1 and Figure 7. This embodiment is based on Example 2, and adds a green light auxiliary light-emitting layer 2331. The green light auxiliary light-emitting layer 2331 uses the same material and doping ratio as the green light-emitting layer 2312. The green light auxiliary light-emitting layer 2331 effectively expands the exciton recombination area in the green light-emitting layer 2312, thereby improving the light-emitting stability and further improving the device life.

[0144] Example 4:

[0145] First electrode 1: metal Ag (thickness 100nm) / ITO layer (thickness 8nm) / ;

[0146] First hole transport layer 21: HT (hole transport): p-type (thickness 10 nm, doping concentration 3%) / HT (hole transport) (B color adjustment);

[0147] a first common electron blocking layer 22 (5 nm thick);

[0148] First light-emitting layer 23: red electron blocking layer 2321 / red light-emitting layer 2311: RH (Red Host) + RD (Red Dopant) (doping 3%); green auxiliary light-emitting layer 2331: GH (Green Host) + G-TADF (ratio of 70%:30%) / green light-emitting layer 2312: green light-emitting layer 2312: GH (Green Host) + G-TADF + GD (green dopant) (ratio of 69%:30%:1.0%); blue electron blocking layer 2322 (thickness 5 nm) / blue light-emitting layer 2313: BH (Blue Host) + BD (Blue Dopant) (doping 3%);

[0149] First hole blocking layer 24: HB (5 nm);

[0150] Charge generation structure 5: N-type charge generation layer 51: n-CG: Yb (1%) / P-type charge generation layer 52: HT: p-type (thickness 10 nm, doping concentration 10%);

[0151] a second hole transport layer 61;

[0152] A second common electron blocking layer 62 (5 nm thick);

[0153] Second light-emitting layer 63: red electron blocking layer 2321 / red light-emitting layer 2311: RH (Red Host) + RD (Red Dopant) (doping 3%); green auxiliary light-emitting layer 2331: GH (Green Host) + G-TADF (ratio of 80%:20%) / green light-emitting layer 2312: GH (Green Host) + G-TADF + GD (green dopant) (ratio of 69%:30%:1.0%); blue electron blocking layer 2322 (thickness 5 nm) / blue light-emitting layer 2313: BH (Blue Host) + BD (Blue Dopant) (doping 3%);

[0154] Second hole blocking layer 64: HB (Hole Blocking) (thickness 5 nm);

[0155] First electron transport layer 25: LiQ (liquid Li) (thickness 35 nm, ratio of liquid Li to liquid lead is 50%:50%);

[0156] Electron injection layer 27: EIL (Electron Injecting Layer) (thickness 1 nm);

[0157] Second electrode 3: Mg and Ag alloy (thickness 15 nm) + optical cover layer CPL (capping layer).

[0158] Referring to Table 1 and FIG. 7 , this embodiment is based on Example 3 and improves device efficiency and device life by changing the doping ratio of the auxiliary light-emitting layer 233 .

[0159] Example 5:

[0160] First electrode 1: metal Ag (thickness 100nm) / ITO layer (thickness 8nm) / ;

[0161] First hole transport layer 21: HT (hole transport): p-type (thickness 10 nm, doping concentration 3%) / HT (hole transport) (B color adjustment);

[0162] a first common electron blocking layer 22 (5 nm thick);

[0163] First light-emitting layer 23: red electron blocking layer 2321 / red light-emitting layer 2311: RH (Red Host) + RD (Red Dopant) (doping 3%); green auxiliary light-emitting layer 2331: GH (Green Host) + G-TADF (ratio of 50%:50%) / green light-emitting layer 2312: green light-emitting layer 2312: GH (Green Host) + G-TADF + GD (green dopant) (ratio of 69%:30%:1.0%); blue electron blocking layer 2322 (thickness 5 nm) / blue light-emitting layer 2313: BH (Blue Host) + BD (Blue Dopant) (doping 3%);

[0164] First hole blocking layer 24: HB (5 nm);

[0165] Charge generation structure 5: N-type charge generation layer 51: n-CG: Yb (1%) / P-type charge generation layer 52: HT: p-type (thickness 10 nm, doping concentration 10%);

[0166] a second hole transport layer 61;

[0167] A second common electron blocking layer 62 (5 nm thick);

[0168] Second light-emitting layer 63: red electron blocking layer 2321 / red light-emitting layer 2311: RH (Red Host) + RD (Red Dopant) (doping 3%); green auxiliary light-emitting layer 2331: GH (Green Host) + G-TADF (ratio of 80%:20%) / green light-emitting layer 2312: GH (Green Host) + G-TADF + GD (green dopant) (ratio of 69%:30%:1.0%); blue electron blocking layer 2322 (thickness 5 nm) / blue light-emitting layer 2313: BH (Blue Host) + BD (Blue Dopant) (doping 3%);

[0169] Second hole blocking layer 64: HB (Hole Blocking) (thickness 5 nm);

[0170] First electron transport layer 25: LiQ (liquid Li) (thickness 35 nm, ratio of liquid Li to liquid lead is 50%:50%);

[0171] Electron injection layer 27: EIL (Electron Injecting Layer) (thickness 1 nm);

[0172] Second electrode 3: Mg and Ag alloy (thickness 15 nm) + optical cover layer CPL (capping layer).

[0173] Referring to Table 1 and FIG. 7 , this embodiment changes the doping ratio of the auxiliary light-emitting layer 233 in Example 4, thereby improving the device efficiency and device life.

[0174] Example 6:

[0175] First electrode 1: metal Ag (thickness 100nm) / ITO layer (thickness 8nm) / ;

[0176] First hole transport layer 21: HT (hole transport): p-type (thickness 10 nm, doping concentration 3%) / HT (hole transport) (B color adjustment);

[0177] a first common electron blocking layer 22 (5 nm thick);

[0178] First light-emitting layer 23: Red electron blocking layer 2321: First blocking layer 2321a + second blocking layer 2321b / Red light-emitting layer 2311: RH (Red Host) + RD (Red Dopant) (doping 3%); Green light-emitting layer 2312: GH (Green Host) + G-TADF + GD (green dopant) (ratio of 69%:30%:1.0%); Blue electron blocking layer 2322 (thickness 5nm) / Blue light-emitting layer 2313: BH (Blue Host) + BD (Blue Dopant) (doping 3%);

[0179] First hole blocking layer 24: HB (5 nm);

[0180] Charge generation structure 5: N-type charge generation layer 51: n-CG: Yb (1%) / P-type charge generation layer 52: HT: p-type (thickness 10 nm, doping concentration 10%);

[0181] a second hole transport layer 61;

[0182] A second common electron blocking layer 62 (5 nm thick);

[0183] Second light-emitting layer 63: Red electron blocking layer 2321: First blocking layer 2321a + Second blocking layer 2321b / Red light-emitting layer 2311: RH (Red Host) + RD (Red Dopant) (3% doping); Green light-emitting layer 2312: GH (Green Host) + G-TADF + GD (Green dopant) (ratio of 69%:30%:1.0%); Blue electron blocking layer 2322 (5 nm thick) / Blue light-emitting layer 2313: BH (Blue Host) + BD (Blue Dopant) (3% doping);

[0184] Second hole blocking layer 64: HB (Hole Blocking) (thickness 5 nm);

[0185] First electron transport layer 25: LiQ (liquid Li) (thickness 35 nm, ratio of liquid Li to liquid lead is 50%:50%);

[0186] Electron injection layer 27: EIL (Electron Injecting Layer) (thickness 1 nm);

[0187] Second electrode 3: Mg and Ag alloy (thickness 15 nm) + optical cover layer CPL (capping layer).

[0188] As shown in Table 1 and FIG11 , this embodiment is based on Example 2, with the addition of a red light electron blocking layer. This effectively increases the red light voltage, reduces the voltage difference, improves the crosstalk problem, and improves the red light device efficiency to a certain extent, thereby reducing the power consumption of the overall red and blue light devices. Furthermore, the number of chambers and fine metal masks remains unchanged, the process complexity remains essentially unchanged, and the performance of the green and blue light devices remains essentially unchanged.

[0189] An embodiment of the present application further provides a display device, comprising the above-mentioned display panel.

[0190] It should be noted that the display device in this embodiment can be any product or component with a display function, such as electronic paper, a mobile phone, a tablet computer, a television, a laptop computer, a digital photo frame, or a navigator.

[0191] It should be noted that in the accompanying drawings, the sizes of layers and regions may be exaggerated for clarity of illustration. It will also be understood that when an element or layer is referred to as being "on" another element or layer, it may be directly on the other element, or there may be an intermediate layer. In addition, it will be understood that when an element or layer is referred to as being "under" another element or layer, it may be directly under the other element, or there may be more than one intermediate layer or element. In addition, it will also be understood that when a layer or element is referred to as being "between" two layers or elements, it may be the only layer between the two layers or elements, or there may also be more than one intermediate layer or element. Similar reference numerals throughout the text indicate similar elements.

[0192] In this application, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance. The term "plurality" refers to two or more than two, unless otherwise clearly defined.

[0193] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the disclosure disclosed herein. This application is intended to cover any variations, uses, or adaptations of the present application that follow the general principles of the present application and include common knowledge or customary techniques in the art not disclosed herein. The description and examples are to be considered as exemplary only, and the true scope and spirit of the present application are indicated by the following claims.

[0194] It should be understood that the present application is not limited to the exact structures described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present application is limited only by the appended claims.

Claims

1. A display panel, characterized in that: The display panel includes a light-emitting structure, which includes: a first electrode, a first light-emitting unit and a second electrode; the first light-emitting unit is arranged on one side of the first electrode, and the second electrode is arranged on the side of the first light-emitting unit facing away from the first electrode; the first light-emitting unit includes a first hole transport layer, a first electron transport layer, a first light-emitting layer located between the first hole transport layer and the first electron transport layer, and a first common electron blocking layer located between the first hole transport layer and the first light-emitting layer; the first light-emitting layer includes three sub-light-emitting layers, at least one of the sub-light-emitting layers contains a material having thermally activated delayed fluorescence properties.

2. The display panel according to claim 1, characterized in that: The three sub-light-emitting layers are arranged at intervals and between the first common electron blocking layer and the first electron transport layer; the area of ​​the first common electron blocking layer is greater than or equal to the sum of the areas of the three sub-light-emitting layers.

3. The display panel according to claim 2, characterized in that: The first light-emitting layer further includes a sub-electron blocking layer; the number of the sub-electron blocking layer is the same as the number of the sub-light-emitting layer that does not include the material having thermally activated delayed fluorescence characteristics.

4. The display panel according to claim 3, characterized in that: The area of ​​the sub-electron blocking layer is greater than or equal to the area of ​​the sub-light-emitting layer that does not contain the material having the thermally activated delayed fluorescence property; the sub-electron blocking layer is arranged one-to-one below the sub-light-emitting layer that does not contain the material having the thermally activated delayed fluorescence property and is located between the sub-light-emitting layer that does not contain the material having the thermally activated delayed fluorescence property and the first common electron blocking layer.

5. The display panel according to claim 3, characterized in that: The first light-emitting layer also includes an auxiliary light-emitting layer, the number of the auxiliary light-emitting layers is less than or equal to the number of the sub-light-emitting layers containing the material having the thermally activated delayed fluorescence property, and the area of ​​the auxiliary light-emitting layer is greater than or equal to the area of ​​the sub-light-emitting layer containing the material having the thermally activated delayed fluorescence property; the auxiliary light-emitting layers are arranged one by one below the sub-light-emitting layer containing the material having the thermally activated delayed fluorescence property and between the sub-light-emitting layer containing the material having the thermally activated delayed fluorescence property and the first common electron blocking layer.

6. The display panel according to claim 5, characterized in that: The thickness of the auxiliary light-emitting layer is smaller than the thickness of the corresponding sub-light-emitting layer; the auxiliary light-emitting layer comprises a light-emitting main material and a material having thermally activated delayed fluorescence characteristics, and the light-emitting main material and the material having thermally activated delayed fluorescence characteristics are the same as the material of the sub-light-emitting layer corresponding to the auxiliary light-emitting layer.

7. The display panel according to claim 5, characterized in that: The sub-light-emitting layer includes a red light-emitting layer, a green light-emitting layer and a blue light-emitting layer, and only the green light-emitting layer contains a material with thermally activated delayed fluorescence characteristics; the sub-electron blocking layer includes a red light-emitting electron blocking layer and a blue light-emitting layer, and the red light-emitting electron blocking layer and the blue light-emitting layer are respectively and correspondingly arranged below the red light-emitting layer and the blue light-emitting layer; the auxiliary light-emitting layer includes a green light auxiliary light-emitting layer; the green light auxiliary light-emitting layer is arranged below the green light-emitting layer; the first excited triplet energy level value of the first common electron blocking layer is greater than or equal to the first excited triplet energy level value of the thermally activated delayed fluorescence characteristic material contained in the green light-emitting layer.

8. The display panel according to claim 7, characterized in that: The first common electron blocking layer is made of hole-type carbazole or aromatic amine derivatives, and the thickness of the first common electron blocking layer is less than or equal to 10 nm.

9. The display panel according to claim 7, characterized in that: The highest occupied molecular orbital value of the blue photon electron blocking layer is greater than the highest occupied molecular orbital value of the blue light emitting layer, and less than the highest occupied molecular orbital value of the first hole transport layer; the S1 value of the blue light electron blocking layer is greater than the singlet excited state value of the blue light emitting layer.

10. The display panel according to claim 7, characterized in that: The absolute value of the highest occupied molecular orbital value of the first common electron blocking layer and the highest occupied molecular orbital value of the first hole transport layer, the absolute value of the highest occupied molecular orbital value of the first common electron blocking layer and the highest occupied molecular orbital value of the blue light electron blocking layer, and the absolute value of the highest occupied molecular orbital value of the first common electron blocking layer and the highest occupied molecular orbital value of the red light electron blocking layer are all less than or equal to 0.25 eV.

11. The display panel according to claim 1, characterized in that: The light-emitting structure further includes a first hole blocking layer; the first hole blocking layer is disposed on a side of the first light-emitting unit that is away from the first electrode and is located between the first light-emitting unit and the second electrode.

12. The display panel according to any one of claims 1 to 11, characterized in that: The light-emitting structure further includes a charge generation structure and a second light-emitting unit; the charge generation structure is arranged on a side of the first light-emitting unit facing away from the first electrode; the second light-emitting unit is arranged on a side of the charge generation structure facing away from the first electrode.

13. The display panel according to claim 12, characterized in that: The second light-emitting unit includes a second hole transport layer, a second light-emitting layer located between the second hole transport layer and the first electron transport layer, and a second common electron blocking layer located between the second hole transport layer and the second light-emitting layer; the second light-emitting layer includes three sub-light-emitting layers, at least one of the sub-light-emitting layers contains a material having thermally activated delayed fluorescence properties.

14. The display panel according to claim 12, characterized in that: The charge generation structure includes an N-type charge generation layer and a P-type charge generation layer; the N-type charge generation layer is arranged on the side of the first light-emitting unit facing away from the first electrode; the P-type charge generation layer is arranged on the side of the N-type charge generation layer facing away from the first electrode.

15. The display panel according to claim 12, characterized in that: The light-emitting structure also includes a hole injection layer and an electron injection layer; the first electrode is an anode, and the second electrode is a cathode; the hole injection layer is arranged between the first hole transport layer and the first electrode; the electron injection layer is arranged between the first electron transport layer and the second electrode.

16. A display device, characterized in that: Comprising the display panel as claimed in any one of claims 1 to 15.

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