Display panel and display device
By introducing a first common electron blocking layer into the OLED display device, the problems of complex structure and high cost of TADF system devices are solved, and the process flow is simplified and the electron transport efficiency is improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- BOE TECHNOLOGY GROUP CO LTD
- Filing Date
- 2023-09-28
- Publication Date
- 2026-04-28
AI Technical Summary
The device structure of existing OLED display devices using the TADF system is relatively complex, which increases the difficulty and cost of manufacturing processes.
The light-emitting structure design, which includes a first shared electron blocking layer, reduces the number of vapor deposition chambers and fine metal films. By setting the first shared electron blocking layer, electrons are blocked from the sub-light-emitting layer containing thermally activated delayed fluorescence material, thus simplifying the process.
This reduces the difficulty and cost of manufacturing processes while improving electron transmission efficiency and luminescence effect.
Smart Images
Figure CN117082889B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of display technology, and more particularly to display panels and display devices. Background Technology
[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-illumination, fast response speed, high brightness, wide viewing angle, and flexible display.
[0003] In OLED display devices, sensitized fluorescence technology is commonly used, especially TADF (Thermally Activated Delayed Fluorescence), which combines high efficiency with the high color purity of phosphors. Therefore, it has a technological advantage over traditional fluorescence and phosphorescence technologies in the display field. However, the device structure using TADF is currently more complex than that of ordinary phosphorescent devices, requiring additional evaporation equipment, which increases the difficulty and cost of manufacturing processes. Summary of the Invention
[0004] This application provides a display panel and a display device to address the shortcomings of related technologies.
[0005] According to a first aspect of the present application, a display panel is provided, the display panel including a light-emitting structure, the light-emitting structure including: a first electrode, a first light-emitting unit, and a second electrode; the first light-emitting unit is disposed on one side of the first electrode, and the second electrode is disposed on the side of the first light-emitting unit opposite to 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 comprising a material having thermosensitive properties.
[0006] 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; 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.
[0007] Furthermore, the first luminescent layer also includes sub-electron blocking layers; the number of sub-electron blocking layers is the same as the number of sub-luminescent layers that do not contain materials with thermally activated delayed fluorescence properties.
[0008] Furthermore, the area of the sub-electron blocking layer is greater than or equal to the area of the sub-emitting layer that does not contain materials with thermally activated delayed fluorescence characteristics; the sub-electron blocking layers are disposed one-to-one below the sub-emitting layers that do not contain materials with thermally activated delayed fluorescence characteristics and between the sub-emitting layers that do not contain materials with thermally activated delayed fluorescence characteristics and the first common electron blocking layer.
[0009] Furthermore, the first light-emitting layer further includes auxiliary light-emitting layers, the number of which is the same as the number of sub-light-emitting layers containing the material with thermally activated delayed fluorescence properties, and the area of the auxiliary light-emitting layers is greater than or equal to the area of the sub-light-emitting layers containing the material with thermally activated delayed fluorescence properties; the auxiliary light-emitting layers are disposed one-to-one below the sub-light-emitting layers containing the material with thermally activated delayed fluorescence properties and between the sub-light-emitting layers containing the material with thermally activated delayed fluorescence properties and the first common electron blocking layer.
[0010] Furthermore, the thickness of the auxiliary light-emitting layer is less than the thickness of the corresponding sub-light-emitting layer; the auxiliary light-emitting layer comprises a light-emitting host material and a material with thermally activated delayed fluorescence characteristics, and the light-emitting host material and the material with thermally activated delayed fluorescence characteristics are the same as the material of the sub-light-emitting layer corresponding to the auxiliary light-emitting layer.
[0011] Further, the sub-emitting layer includes a red light emitting layer, a green light emitting layer, and a blue light emitting layer, with only the green light emitting layer containing a material having thermally activated delayed fluorescence properties; the sub-electron blocking layer includes a red light electron blocking layer and a blue light electron blocking layer, which are respectively disposed below the red light emitting layer and the blue light emitting layer; the auxiliary light emitting layer includes a green auxiliary light emitting layer; the green auxiliary light emitting layer is disposed below the green light emitting layer; the first excited triplet energy level value of the first shared electron blocking layer is greater than or equal to the first excited triplet energy level value of the thermally activated delayed fluorescence material contained in the green light emitting layer.
[0012] Furthermore, the first shared electron blocking layer is made of a hole-type carbazole or aromatic amine derivative, and the thickness of the first shared electron blocking layer is less than or equal to 10 nm.
[0013] Furthermore, the highest occupied molecular orbital value of the blue electron blocking layer is greater than that of the blue light emitting layer, but less than that of the first hole transport layer; the singlet excited state value of the blue electron blocking layer is greater than that of the blue light emitting layer.
[0014] Furthermore, the absolute values of the highest occupied molecular orbital value of the first shared electron blocking layer and the highest occupied molecular orbital value of the first hole transport layer, the absolute values of the highest occupied molecular orbital value of the first shared electron blocking layer and the highest occupied molecular orbital value of the blue electron blocking layer, and the absolute values of the highest occupied molecular orbital value of the first shared electron blocking layer and the highest occupied molecular orbital value of the red electron blocking layer are all less than or equal to 0.25 eV.
[0015] Furthermore, the light-emitting structure also includes a first hole-blocking layer; the first hole-blocking layer is disposed on the 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.
[0016] Furthermore, the light-emitting structure also includes a charge-generating structure and a second light-emitting unit; the charge-generating structure is disposed on the side of the first light-emitting unit facing away from the first electrode; the second light-emitting unit is disposed on the side of the charge-generating structure facing away from the first electrode.
[0017] 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 containing a material with thermally activated delayed fluorescence properties.
[0018] 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 disposed on the side of the first light-emitting unit facing away from the first electrode; the P-type charge generation layer is disposed on the side of the N-type charge generation layer facing away from the first electrode.
[0019] 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 disposed between the first hole transport layer and the first electrode; the electron injection layer is disposed between the first electron transport layer and the second electrode.
[0020] According to a second aspect of the embodiments of this application, a display device is provided, including the display panel described above.
[0021] As can be seen from the above embodiments, by setting a first common electron blocking layer, this application eliminates the need to set a separate electron blocking layer for the sub-emission layer containing thermally activated delayed fluorescence material, thereby reducing the number of evaporation chambers and fine metal thin films, and lowering the difficulty and cost of the manufacturing process.
[0022] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description
[0023] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.
[0024] Figure 1 This is a schematic diagram of the light-emitting structure shown according to an embodiment of this application.
[0025] Figure 2 yes Figure 1 A schematic diagram of the second embodiment of the light-emitting structure shown.
[0026] Figure 3 yes Figure 1 A schematic diagram of the third embodiment of the light-emitting structure shown.
[0027] Figure 4 yes Figure 1 The diagram shows a light-emitting structure with multiple light-emitting units connected in series.
[0028] Figure 5 yes Figure 4 The diagram shown illustrates a light-emitting structure in which only the red light-emitting layer is doped with TADF.
[0029] Figure 6 yes Figure 4 The diagram shown illustrates the luminescent structure in which both the red and green luminescent layers are doped with TADF.
[0030] Figure 7 yes Figure 4 The diagram shows a light-emitting structure with an auxiliary light-emitting layer.
[0031] Figure 8 yes Figure 5 The diagram shows a light-emitting structure with an auxiliary light-emitting layer.
[0032] Figure 9 yes Figure 6 The diagram shows a light-emitting structure with an auxiliary light-emitting layer.
[0033] Figure 10 yes Figure 4 The diagram shown illustrates the luminescent structure with TADF doping of all sub-luminescent layers and the addition of an auxiliary luminescent layer.
[0034] Figure 11 yes Figure 4 A schematic diagram of another embodiment of the light-emitting structure shown.
[0035] Reference numerals: 1. First electrode; 2. First light-emitting unit; 21. First hole transport layer; 22. First shared 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 electron blocking layer; 2321a. First blocking layer; 2321b. Second blocking layer; 2322. Blue electron blocking layer; 2323. Green electron blocking layer; 233. Auxiliary light-emitting layer. Light layer; 2331, Green light-assisted light-emitting layer; 2332, Red light-assisted light-emitting layer; 2333, Blue light-assisted 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 shared electron blocking layer; 63, Second light-emitting layer; 64, Second hole blocking layer. Detailed Implementation
[0036] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.
[0037] Please refer to Figure 1 As shown, this application provides a display panel. The display panel includes a light-emitting structure, which includes 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.
[0038] The first electrode 1 can be either 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.
[0039] In the embodiments of this application, preferably, the first electrode 1 is the anode.
[0040] The first electrode 1 is made of an electrode material with a high work function, such as transparent oxide ITO (indium tin oxide) or IZO (tin zinc oxide). When the above electrode material is used, the thickness of the first electrode 1 can be greater than 80 nm and less than 200 nm. In this case, the display panel provided by this application is a bottom-emitting structure.
[0041] The first electrode 1 can also be a composite electrode formed by metals and oxides 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 is a top-emitting structure.
[0042] The second electrode 3 is therefore a cathode and can be made of a metal with a low work function, such as Al, Ag, or Mg, or an alloy containing a metal with a low work function. 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%.
[0043] When the display panel has a top-emitting structure, the thickness of the second electrode 3 should be adjusted between 10 nm and 20 nm to ensure its transmittance. Preferably, its transmittance for light with a wavelength of 550 nm should be greater than 45%, and an optical capping layer (CPL) should be applied over the metal layer of the second electrode 3 to improve its optical output. Preferably, the optical capping layer should be formed by vapor deposition of a small molecule material with a high refractive index. Further, its refractive index at 550 nm should be greater than 1.8, and its thickness should be greater than 50 nm and less than 100 nm.
[0044] like Figure 1 As shown, an encapsulation layer 4 is disposed above the second electrode 3, encapsulating the first electrode 1, the second electrode 3, and the first light-emitting unit 2 inside to prevent damage from the external environment. The encapsulation layer 4 can be encapsulated using UV sealant or thin-film encapsulation (TFE).
[0045] 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 sequentially from bottom to top.
[0046] The first light-emitting layer 23 includes three sub-light-emitting layers 231, namely a red light-emitting layer 2311, a green light-emitting layer 2312, and a blue light-emitting layer 2313, and at least one of the three sub-light-emitting layers 231 contains a material with thermally activated delayed fluorescence properties. A first common electron blocking layer 22 is also disposed between the first hole transport layer 21 and the first light-emitting layer 23.
[0047] 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 also includes a pixel definition layer (PDL) (not shown in the figure), which is disposed between the three sub-light-emitting layers 231, separating the three sub-light-emitting layers 231. Due to process limitations, in this 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.
[0048] An electron blocking layer (EBL) is a layered material used in semiconductor devices. Its main function is to block unnecessary electron transport or leakage within the device, effectively preventing electrons from entering unrelated layers from the electron transport layer or electrodes. This ensures the accuracy and stability of electron injection, contributing to improved electron transport efficiency and luminescence performance. The electron blocking layer also possesses a band barrier, effectively reducing or blocking leakage current. Furthermore, it can optimize interface matching between different materials, bridging energy level differences and improving electron transport efficiency between materials, thereby reducing band bending, reflection, and other non-ideal phenomena.
[0049] Therefore, the traditional approach typically involves placing a corresponding electron blocking layer under each sub-emitting layer 231. The area of this electron blocking layer should be greater than or equal to the area of its corresponding sub-emitting layer 231, with the thickness of the red electron blocking layer being greater than that of the blue electron blocking layer, and the thickness of the blue electron blocking layer being greater than that of the green electron blocking layer. However, traditional electron blocking layers require the use of fine metal masks and vapor deposition to fabricate, which is a complex and costly process.
[0050] Based on the traditional approach, this application sets up a first common electron blocking layer 22, with all three sub-emissive layers 231 located between the first common electron blocking layer 22 and the first electron transport layer 25. This eliminates the need to set up separate electron blocking layers for the sub-emissive layers 231 containing thermally activated delayed fluorescence materials, thereby reducing the number of electron blocking layers, which in turn reduces the number of vapor deposition chambers and fine metal films, and lowers the manufacturing difficulty and cost.
[0051] Please refer to Figures 1 to 3As shown, at least one sub-emitting layer 231 mentioned in this application contains a material with thermally activated delayed fluorescence properties, which means that one sub-emitting layer 231 can be thermally activated delayed fluorescence doped, or two or even all sub-emitting layers 231 can be thermally activated delayed fluorescence doped.
[0052] When thermally activated delayed fluorescence doping is performed on only one sub-emissive layer 231, please refer to... Figure 1 As shown, taking the thermally activated delayed fluorescence doping of the green emitting layer 2312 as an example, the green emitting layer 2312 does not need to have a separate electron blocking layer; the electron blocking effect can be achieved solely through the first shared electron blocking layer 22. In this case, the red emitting layer 2311 and the blue emitting layer 2313 each have corresponding red electron blocking layers 2321 and 2322 below them. Since both the red emitting layer 2311 and the blue emitting layer 2313 are located above the first shared electron blocking layer 22, the first shared electron blocking layer 22 can further enhance the effects of the red electron blocking layer 2321 and the blue electron blocking layer 2322, respectively.
[0053] This embodiment is not limited to thermally activated delayed fluorescence doping of the green light emitting layer 2312; the red light emitting layer 2311 and the blue light emitting layer 2313 can also be used as embodiments, which will not be described in detail here.
[0054] When performing thermally activated delayed fluorescence doping on the two sub-emissive layers 231, please refer to... Figure 2 As shown, taking 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 their respective separate electron blocking layers. The electron blocking effect can be achieved by the first shared electron blocking layer 22 alone. At this time, a corresponding blue electron blocking layer 2322 is provided below the blue light emitting layer 2313.
[0055] Thermally activated delayed fluorescence doping of the two sub-emitting layers 231 is not limited to red light emitting layer 2311 and green light emitting layer 2312. It is foreseeable that red light emitting layer 2311 and blue light emitting layer 2313, and green light emitting layer 2312 and blue light emitting layer 2313 can also be used as an embodiment, which will not be described in detail here.
[0056] When performing thermally activated delayed fluorescence doping on the three sub-emissive layers 231, please refer to... Figure 3 As shown, the electron blocking effect on all sub-light-emitting layers 231 can be achieved solely through the first common electron blocking layer 22.
[0057] Specifically, please combine Figure 1Taking thermally activated delayed fluorescence doping of a single green emitting layer 2312 as an example, in this embodiment, the hole injection layer 26 can be fabricated using injection materials such as CuPc, HATCN, or MnO3, or it can be formed by p-type doping in a hole transport material. When using a hole transport material for p-type doping, the p-type dopant can optionally be an oxide-based inorganic material or an axialene-based organic 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.
[0058] The first hole transport layer 21 can be formed of a material with good hole transport characteristics, 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.
[0059] The electron injection layer 27 can be formed by vapor deposition using a low work function metal material such as Li, Ca, Yb, or metal salts like 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 embodiments of this application, the electron injection layer 27 is formed by vapor deposition using Yb metal material.
[0060] The first shared electron blocking layer 22 has a high first excited triplet energy level, which is at least as high as the first excited triplet energy level of the thermally activated delayed fluorescent material in the green emitting layer 2312. This layer is used to block exciton leakage from the emitting layer, thereby improving efficiency and stability. The material of the first shared electron blocking layer 22 can be selected from hole-type carbazole or aromatic amine derivatives, and its thickness does not exceed 10 nm.
[0061] The blue electron blocking layer 2322 is used to lower the transport barrier of holes from the adjacent first hole transport layer 21 to the blue light emitting layer 2313. Therefore, the highest occupied orbital energy level of the molecules in this layer should be numerically between the highest occupied orbital energy level of the molecules in the adjacent first hole transport layer 21 and the highest occupied orbital energy level of the molecules in the host material of the blue light emitting layer 2313. Simultaneously, the blue electron blocking layer 2322 also has an exciton blocking effect, ensuring that the energy of the first excited state of the singlet state of this layer is greater than the energy of the first excited state of the singlet state of the blue light emitting layer 2313. Optionally, this layer material can be carbazole or its derivatives.
[0062] The red electron blocking layer 2321 is used to reduce the transport barrier of holes from the adjacent first hole transport layer 21 to the red light emitting layer 2311, while ensuring that excitons in the emitting layer do not leak out. Optionally, the material of this layer can be carbazole and its derivatives.
[0063] The blue emitting layer 2313 comprises at least a host material and a fluorescent guest material. The emission spectrum of the host material and the absorption spectrum of the guest material have significant overlap; under normalized spectral conditions, the area of the overlap region of the host material accounts for no less than 60% of the area of the guest absorption spectrum. The host material may be anthracene, fluorene, pyrene, or their derivatives. The guest material may be a pyrene-based organic compound or a boron-containing organic compound, with a doping concentration adjustable in the range of 0.5% to 5%, and its main emission peak wavelength should be greater than 450 nm and less than 480 nm.
[0064] The green emitting layer 2312 comprises a hole-type host material, a material with thermally activated delayed fluorescence (TEF) properties, and a fluorescent guest material. The hole-type host material can be a carbazole-based material, the TEF material can be a polycarbazole-based material with a DLA structure, and the fluorescent guest material can be a boron-containing organic compound. The first excited triplet energy level of the host material is higher than that of the TEF 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 TEF material. The emission spectrum of the TEF material overlaps significantly with the absorption spectrum of the guest material; optimally, the overlap area of the normalized spectrum of the TEF material should account for more than 60% of the area of the guest absorption spectrum.
[0065] The red emitting layer 2311 comprises at least a P-type host material, an N-type host material, and one emitting guest material. The N-type host material can be a general material or a material with thermally activated delayed fluorescence properties. The emitting guest material can be a phosphorescent material or a boron-containing fluorescent material. The thickness of the red emitting layer 2311 can be adjusted between greater than 30 nm and less than 80 nm.
[0066] 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 should be greater than the first excited triplet energy level of the material with thermally activated delayed fluorescence characteristics in the connected green emitting layer 2312. Preferably, the difference should be greater than or equal to 0.2 eV. The absolute value of the highest occupied orbital energy level of the molecules in the first hole-blocking layer 24 should be greater than the absolute value of the highest occupied orbital energy level of the molecules in all connected sub-emitting layers 231. Preferably, it should be greater than 0.2 eV. The absolute value of the lowest unoccupied orbital energy level of the molecules in the first hole-blocking layer 24 should be less than the absolute value of the lowest unoccupied orbital energy level of the molecules in all connected sub-emitting layers 231.
[0067] The first electron transport layer 25 can be formed by vapor deposition of a material with good electron transport properties, or it can be formed by doping an electron transport material with LIQ3, Li, Ca, and other materials in a certain proportion. The absolute value of the lowest unoccupied orbital energy level of all the molecules in the first electron transport layer 25 must be greater than the absolute value of the lowest unoccupied orbital energy level of the molecules in the connected first hole blocking layer 24.
[0068] It is worth mentioning that the energy levels and mobilities of the first shared electron blocking layer 22 and the adjacent film layers should satisfy the following relationship:
[0069] |HOMO(G EBL) - HOMO(HTL)| ≤ 0.25 eV, preferably ≤ 0.15 eV
[0070] |HOMO(GEBL) - HOMO(BEBL)| ≤ 0.25 eV, preferably ≤ 0.15 eV
[0071] ∣HOMO(G EBL)-HOMO(R EBL)∣≤0.25eV
[0072] Wherein, HOMO (GEBL) refers to the HOMO energy level value of the first shared electron blocking layer 22, HOMO (HTL) refers to the HOMO energy level value of the first hole transport layer 21 (HBL Hole Transporting Layer), HOMO (BEBL) refers to the HOMO energy level value of the blue electron blocking layer 2322, and HOMO (REBL) refers to the HOMO energy level value of the red electron blocking layer 2321.
[0073] At this time, it is ensured that holes can be successfully injected into the red light emitting layer 2311 and the blue light emitting layer 2313;
[0074] 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, so as to facilitate better display of the image. Therefore, it is necessary to satisfy |HOMO(GEBL) - HOMO(REBL)| ≥ |HOMO(GEBL) - HOMO(BEBL)|;
[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, and due to the presence of the first shared electron blocking layer 22, the following hole mobility needs to be satisfied to prevent crosstalk caused by lateral leakage:
[0076] 10 -5 < Hole mobility (GEBL) / Hole mobility (HTL) < 10-3
[0077] 10 -4 < Hole mobility (GEBL) / Hole mobility (REBL) < 10 -2
[0078] 10 -2 < Hole mobility (GEBL) / Hole mobility (BEBL) < 10
[0079] 10 -3 < Hole mobility (BEBL) / Hole mobility (REBL) < 10 -1 .
[0080] Hole mobility (GEBL) refers to the hole mobility of the first common electron blocking layer 22, hole mobility (HTL) refers to the hole mobility of the first hole transport layer 21 (HBL Hole Transporting Layer), hole mobility (BEBL) refers to the hole mobility of the blue electron blocking layer 2322, and hole mobility (REBL) refers to the hole mobility of the red electron blocking layer 2321.
[0081] The light-emitting structure in the above embodiments includes only one light-emitting unit. In another embodiment, please refer to... Figures 4 to 11 As shown, the light-emitting structure provided in this application further includes a charge-generating structure 5 and a second light-emitting unit 6. The charge-generating 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-generating structure 5 facing away from the first electrode 1.
[0082] In this embodiment, a light-emitting structure is formed by two light-emitting units connected in series with a charge generation structure 5. Alternatively, a light-emitting structure can be formed by three or more light-emitting units connected in series with a charge generation structure 5. This embodiment does not limit the specific light-emitting structure to this.
[0083] 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 contains a material with thermally activated delayed fluorescence properties.
[0084] 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.
[0085] The N-type charge generation layer 51 can be formed by doping an electron transport material with a low work function active metal, such as Li, Ca, or Yb.
[0086] 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 P-type dopant in the P-type charge generation layer 52 needs to be higher than the doping proportion in the hole injection layer 26, which is beneficial for charge generation.
[0087] In this embodiment, the structure of the second light-emitting unit 6 is the same as that of the first light-emitting unit 2. The materials constituting each film layer of the second light-emitting unit 6 can be the same as or different from the materials of the first light-emitting unit 2.
[0088] Please refer to Figures 7 to 10 As shown, 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 with doped thermally activated delayed fluorescence characteristics and the first shared electron blocking layer 22. Figure 7 In the embodiment shown, a green auxiliary light-emitting layer 2331 is disposed below the green light-emitting layer 2312.
[0089] The thickness of the green light-assisted luminescent layer 2331 is less than the thickness of the green light-emitting layer 2312. The green light-assisted luminescent layer 2331 includes a luminescent host material and a material with thermally activated delayed fluorescence properties, and the luminescent host material and the material with thermally activated delayed fluorescence properties are the same as those in the green light-emitting layer 2312.
[0090] like Figure 8 As shown, in this embodiment, the red light emitting layer 2311 is thermally activated delayed fluorescence doped, and therefore a red light auxiliary emitting layer 2332 is provided under the red light emitting layer 2311.
[0091] The thickness of the red light-assisted luminescent layer 2332 is less than the thickness of the red light-emitting layer 2311. The red light-assisted luminescent layer 2332 includes a luminescent host material and a material with thermally activated delayed fluorescence properties, and the luminescent host material and the material with thermally activated delayed fluorescence properties are the same as those in the red light-emitting layer 2311.
[0092] like Figure 9 As shown, in this embodiment, both the red light emitting layer 2311 and the green light emitting layer 2312 are thermally activated delayed fluorescence doped. Therefore, a red light auxiliary emitting layer 2332 and a green light auxiliary emitting layer 2331 are respectively provided under the red light emitting layer 2311 and the green light emitting layer 2312.
[0093] The properties of the red light-assisted luminescent layer 2332 and the green light-assisted luminescent layer 2331 have been described above. Figure 8 The embodiments described herein will not be repeated here.
[0094] like Figure 10 As shown, in this embodiment, all sub-emitting layers 231 are thermally activated delayed fluorescence doped, and therefore, auxiliary emitting layers 233 are respectively provided under each sub-emitting layer 231. In this embodiment, the auxiliary emitting layers 233 include a green auxiliary emitting layer 2331, a red auxiliary emitting layer 2332, and a blue auxiliary emitting layer 2333.
[0095] The red light-assisted light-emitting layer 2332 and the green light-assisted light-emitting layer 2331 have been described in the above embodiments and will not be repeated here. For the blue light-assisted light-emitting layer 2333, the thickness of the blue light-assisted light-emitting layer 2333 is less than the thickness of the blue light-emitting layer 2313. The blue light-assisted light-emitting layer 2333 comprises a light-emitting host material and a material with thermally activated delayed fluorescence properties, and the light-emitting host material and the material with thermally activated delayed fluorescence properties are the same as those in the blue light-emitting layer 2313.
[0096] Please refer to Figure 11 As shown, in this embodiment, the red electron blocking layer 2321 includes a first blocking layer 2321a and a second blocking layer 2321b. The first blocking layer 2321a and the second blocking layer 2321b are stacked to form the red electron blocking layer 2321, thereby effectively increasing the voltage of the red light emitting layer 2311, reducing the voltage difference between the red light emitting layer 2311 and the blue light emitting layer 2313, improving crosstalk, improving the device efficiency of the red light emitting layer 2311, and reducing the overall power consumption of the device.
[0097] The specific structure and characteristics of the device formed by the embodiments of this application are as follows:
[0098] Table 1
[0099]
[0100] Example 1:
[0101] From bottom to top, they are:
[0102] First electrode 1: Metal Ag (100nm thick) / ITO layer (8nm thick) / ;
[0103] First hole transport layer 21: HT (hole transport): p-type (10nm thick, 3% doping concentration) / HT (hole transport) (B color adjustment);
[0104] First emitting layer 23: Red electron blocking layer 2321 / Red emitting layer 2311: RH (Red Host) + RD (Red Dopant) (3% doping); Green electron blocking layer 2323 / Green emitting layer 2312: GH (Green Host) + G-TADF + GD (Green Dopant) (ratio 69%:30%:1.0%); Blue electron blocking layer 2322 (5nm thick) / Blue emitting layer 2313: BH (Blue Host) + BD (Blue Dopant) (3% doping);
[0105] First hole-blocking layer 24: HB (5nm);
[0106] Charge generation structure 5: N-type charge generation layer 51: n-CG: Yb (1%) / P-type charge generation layer 52: HT: p-type (10nm thick, 10% doping concentration);
[0107] Second hole transport layer 61;
[0108] Second emitting layer 63: Red electron blocking layer 2321 / Red emitting layer 2311: RH (Red Host) + RD (Red Dopant) (3% doping); Green electron blocking layer 2323 / Green emitting layer 2312: GH (Green Host) + G-TADF + GD (Green Dopant) (ratio 69%:30%:1.0%); Blue electron blocking layer 2322 (5nm thick) / Blue emitting layer 2313: BH (Blue Host) + BD (Blue Dopant) (3% doping);
[0109] Second hole blocking layer 64: HB (Hole Blocking) (5nm thick);
[0110] First electron transport layer 25: LiQ (liquid Li) (35nm thick, the ratio of liquid Li to liquid lead is 50%:50%);
[0111] Electron injection layer 27: EIL (Electron Injecting Layer) (1nm thick);
[0112] Second electrode 3: Mg and Ag alloy (15nm thick) + optical capping layer CPL (capping layer).
[0113] This embodiment 1 uses a conventional method of setting a corresponding electron blocking layer under each sub-light-emitting layer 231 as a comparative example.
[0114] Example 2:
[0115] First electrode 1: Metal Ag (100nm thick) / ITO layer (8nm thick) / ;
[0116] First hole transport layer 21: HT (hole transport): p-type (10nm thick, 3% doping concentration) / HT (hole transport) (B color adjustment);
[0117] First common electron blocking layer 22 (5nm thick);
[0118] First emitting layer 23: Red electron blocking layer 2321 / Red emitting layer 2311: RH (Red Host) + RD (Red Dopant) (3% doping); Green emitting layer 2312: GH (Green Host) + G-TADF + GD (Green Dopant) (ratio 69%:30%:1.0%); Blue electron blocking layer 2322 (5nm thick) / Blue emitting layer 2313: BH (Blue Host) + BD (Blue Dopant) (3% doping);
[0119] First hole-blocking layer 24: HB (5nm);
[0120] Charge generation structure 5: N-type charge generation layer 51: n-CG: Yb (1%) / P-type charge generation layer 52: HT: p-type (10nm thick, 10% doping concentration);
[0121] Second hole transport layer 61;
[0122] Second common electron blocking layer 62 (5nm thick);
[0123] Second emitting layer 63: Red electron blocking layer 2321 / Red emitting layer 2311: RH (Red Host) + RD (Red Dopant) (3% doping); Green emitting layer 2312: GH (Green Host) + G-TADF + GD (Green Dopant) (ratio 69%:30%:1.0%); Blue electron blocking layer 2322 (5nm thick) / Blue emitting layer 2313: BH (Blue Host) + BD (Blue Dopant) (3% doping);
[0124] Second hole blocking layer 64: HB (Hole Blocking) (5nm thick);
[0125] First electron transport layer 25: LiQ (liquid Li) (35nm thick, the ratio of liquid Li to liquid lead is 50%:50%);
[0126] Electron injection layer 27: EIL (Electron Injecting Layer) (1nm thick);
[0127] Second electrode 3: Mg and Ag alloy (15nm thick) + optical capping layer CPL (capping layer).
[0128] Please refer to Table 1 and... Figure 4 As shown, this embodiment adds a first common electron blocking layer 22, and its device performance is basically equivalent to that of Embodiment 1. However, compared with Embodiment 1, Embodiment 2 reduces one chamber and fine metal mask, effectively reducing the process flow and lowering costs.
[0129] Example 3:
[0130] First electrode 1: Metal Ag (100nm thick) / ITO layer (8nm thick) / ;
[0131] First hole transport layer 21: HT (hole transport): p-type (10nm thick, 3% doping concentration) / HT (hole transport) (B color adjustment);
[0132] First common electron blocking layer 22 (5nm thick);
[0133] First emitting layer 23: Red electron blocking layer 2321 / Red emitting layer 2311: RH (Red Host) + RD (Red Dopant) (3% doping); Green auxiliary emitting layer 2331: GH (Green Host) + G-TADF (70%:30%) / Green emitting layer 2312: GH (Green Host) + G-TADF + GD (69%:30%:1.0%); Blue electron blocking layer 2322 (5nm thick) / Blue emitting layer 2313: BH (Blue Host) + BD (Blue Dopant) (3% doping);
[0134] First hole-blocking layer 24: HB (5nm);
[0135] Charge generation structure 5: N-type charge generation layer 51: n-CG: Yb (1%) / P-type charge generation layer 52: HT: p-type (10nm thick, 10% doping concentration);
[0136] Second hole transport layer 61;
[0137] Second common electron blocking layer 62 (5nm thick);
[0138] Second emitting layer 63: Red electron blocking layer 2321 / Red emitting layer 2311: RH (Red Host) + RD (Red Dopant) (3% doping); Green auxiliary emitting layer 2331: GH (Green Host) + G-TADF (70%:30%) / Green emitting layer 2312: GH (Green Host) + G-TADF + GD (Green Dopant) (69%:30%:1.0%); Blue electron blocking layer 2322 (5nm thick) / Blue emitting layer 2313: BH (Blue Host) + BD (Blue Dopant) (3% doping);
[0139] Second hole blocking layer 64: HB (Hole Blocking) (5nm thick);
[0140] First electron transport layer 25: LiQ (liquid Li) (35nm thick, the ratio of liquid Li to liquid lead is 50%:50%);
[0141] Electron injection layer 27: EIL (Electron Injecting Layer) (1nm thick);
[0142] Second electrode 3: Mg and Ag alloy (15nm thick) + optical capping layer CPL (capping layer).
[0143] Please refer to Table 1 and... Figure 7 As shown, this embodiment is based on embodiment 2, with the addition of a green light-assisted light-emitting layer 2331. The green light-assisted light-emitting layer 2331 uses the same material and doping ratio as the green light-emitting layer 2312. The green light-assisted light-emitting layer 2331 effectively expands the exciton recombination region in the green light-emitting layer 2312, thereby improving the light emission stability and thus improving the device lifetime.
[0144] Example 4:
[0145] First electrode 1: Metal Ag (100nm thick) / ITO layer (8nm thick) / ;
[0146] First hole transport layer 21: HT (hole transport): p-type (10nm thick, 3% doping concentration) / HT (hole transport) (B color adjustment);
[0147] First common electron blocking layer 22 (5nm thick);
[0148] First emitting layer 23: Red electron blocking layer 2321 / Red emitting layer 2311: RH (Red Host) + RD (Red Dopant) (3% doping); Green auxiliary emitting layer 2331: GH (Green Host) + G-TADF (70%:30%) / Green emitting layer 2312: GH (Green Host) + G-TADF + GD (69%:30%:1.0%); Blue electron blocking layer 2322 (5nm thick) / Blue emitting layer 2313: BH (Blue Host) + BD (Blue Dopant) (3% doping);
[0149] First hole-blocking layer 24: HB (5nm);
[0150] Charge generation structure 5: N-type charge generation layer 51: n-CG: Yb (1%) / P-type charge generation layer 52: HT: p-type (10nm thick, 10% doping concentration);
[0151] Second hole transport layer 61;
[0152] Second common electron blocking layer 62 (5nm thick);
[0153] Second emitting layer 63: Red electron blocking layer 2321 / Red emitting layer 2311: RH (Red Host) + RD (Red Dopant) (3% doping); Green auxiliary emitting layer 2331: GH (Green Host) + G-TADF (80%:20%) / Green emitting layer 2312: GH (Green Host) + G-TADF + GD (69%:30%:1.0%); Blue electron blocking layer 2322 (5nm thick) / Blue emitting layer 2313: BH (Blue Host) + BD (Blue Dopant) (3% doping);
[0154] Second hole blocking layer 64: HB (Hole Blocking) (5nm thick);
[0155] First electron transport layer 25: LiQ (liquid Li) (35nm thick, the ratio of liquid Li to liquid lead is 50%:50%);
[0156] Electron injection layer 27: EIL (Electron Injecting Layer) (1nm thick);
[0157] Second electrode 3: Mg and Ag alloy (15nm thick) + optical capping layer CPL (capping layer).
[0158] Please refer to Table 1 and... Figure 7 As shown, this embodiment is based on embodiment 3, and improves device efficiency and device lifetime by changing the doping ratio of the auxiliary light-emitting layer 233.
[0159] Example 5:
[0160] First electrode 1: Metal Ag (100nm thick) / ITO layer (8nm thick) / ;
[0161] First hole transport layer 21: HT (hole transport): p-type (10nm thick, 3% doping concentration) / HT (hole transport) (B color adjustment);
[0162] First common electron blocking layer 22 (5nm thick);
[0163] First emitting layer 23: Red electron blocking layer 2321 / Red emitting layer 2311: RH (Red Host) + RD (Red Dopant) (3% doping); Green auxiliary emitting layer 2331: GH (Green Host) + G-TADF (50%:50%) / Green emitting layer 2312: GH (Green Host) + G-TADF + GD (69%:30%:1.0%); Blue electron blocking layer 2322 (5nm thick) / Blue emitting layer 2313: BH (Blue Host) + BD (Blue Dopant) (3% doping);
[0164] First hole-blocking layer 24: HB (5nm);
[0165] Charge generation structure 5: N-type charge generation layer 51: n-CG: Yb (1%) / P-type charge generation layer 52: HT: p-type (10nm thick, 10% doping concentration);
[0166] Second hole transport layer 61;
[0167] Second common electron blocking layer 62 (5nm thick);
[0168] Second emitting layer 63: Red electron blocking layer 2321 / Red emitting layer 2311: RH (Red Host) + RD (Red Dopant) (3% doping); Green auxiliary emitting layer 2331: GH (Green Host) + G-TADF (80%:20%) / Green emitting layer 2312: GH (Green Host) + G-TADF + GD (69%:30%:1.0%); Blue electron blocking layer 2322 (5nm thick) / Blue emitting layer 2313: BH (Blue Host) + BD (Blue Dopant) (3% doping);
[0169] Second hole blocking layer 64: HB (Hole Blocking) (5nm thick);
[0170] First electron transport layer 25: LiQ (liquid Li) (35nm thick, the ratio of liquid Li to liquid lead is 50%:50%);
[0171] Electron injection layer 27: EIL (Electron Injecting Layer) (1nm thick);
[0172] Second electrode 3: Mg and Ag alloy (15nm thick) + optical capping layer CPL (capping layer).
[0173] Please refer to Table 1 and... Figure 7 As shown, this embodiment changes the doping ratio of the auxiliary light-emitting layer 233 in embodiment 4, thereby improving device efficiency and device lifetime.
[0174] Example 6:
[0175] First electrode 1: Metal Ag (100nm thick) / ITO layer (8nm thick) / ;
[0176] First hole transport layer 21: HT (hole transport): p-type (10nm thick, 3% doping concentration) / HT (hole transport) (B color adjustment);
[0177] First common electron blocking layer 22 (5nm thick);
[0178] First emitting layer 23: Red electron blocking layer 2321: First blocking layer 2321a + Second blocking layer 2321b / Red emitting layer 2311: RH (Red Host) + RD (Red Dopant) (3% doping); Green emitting layer 2312: GH (Green Host) + G-TADF + GD (Green Dopant) (ratio 69%:30%:1.0%); Blue electron blocking layer 2322 (5nm thick) / Blue emitting layer 2313: BH (Blue Host) + BD (Blue Dopant) (3% doping);
[0179] First hole-blocking layer 24: HB (5nm);
[0180] Charge generation structure 5: N-type charge generation layer 51: n-CG: Yb (1%) / P-type charge generation layer 52: HT: p-type (10nm thick, 10% doping concentration);
[0181] Second hole transport layer 61;
[0182] Second common electron blocking layer 62 (5nm thick);
[0183] Second emitting layer 63: Red electron blocking layer 2321: First blocking layer 2321a + Second blocking layer 2321b / Red emitting layer 2311: RH (Red Host) + RD (Red Dopant) (3% doping); Green emitting layer 2312: GH (Green Host) + G-TADF + GD (Green Dopant) (ratio 69%:30%:1.0%); Blue electron blocking layer 2322 (5nm thick) / Blue emitting layer 2313: BH (Blue Host) + BD (Blue Dopant) (3% doping);
[0184] Second hole blocking layer 64: HB (Hole Blocking) (5nm thick);
[0185] First electron transport layer 25: LiQ (liquid Li) (35nm thick, the ratio of liquid Li to liquid lead is 50%:50%);
[0186] Electron injection layer 27: EIL (Electron Injecting Layer) (1nm thick);
[0187] Second electrode 3: Mg and Ag alloy (15nm thick) + optical capping layer CPL (capping layer).
[0188] Please refer to Table 1 and... Figure 11 As shown, this embodiment is based on embodiment 2, with the addition of a red light electron blocking layer, which can effectively increase the red light voltage, reduce the voltage difference between them, improve the crosstalk problem, and improve the device efficiency of red light to a certain extent. It can also reduce the power consumption of the overall red and blue light devices. At the same time, the number of chambers and fine metal masks remains unchanged, the process complexity remains basically unchanged, and the device performance of green and blue light remains basically unchanged.
[0189] Embodiments of this application also provide a display device including the display panel described above.
[0190] It should be noted that the display device in this embodiment can be any product or component with display function, such as electronic paper, mobile phone, tablet computer, television, laptop computer, digital photo frame, or navigator.
[0191] It should be noted that the dimensions of layers and regions may be exaggerated in the accompanying drawings for clarity. Furthermore, it is understood that when an element or layer is referred to as being "on" another element or layer, it can be directly on the other element, or there may be intermediate layers. Additionally, it is understood that when an element or layer is referred to as being "below" another element or layer, it can be directly below the other element, or there may be more than one intermediate layer or element. Furthermore, it is also understood that when a layer or element is referred to as being "between" two layers or two elements, it can be the only layer between the two layers or two elements, or there may be more than one intermediate layer or element. Similar reference numerals throughout indicate similar elements.
[0192] In this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The term "multiple" refers to two or more unless otherwise expressly defined.
[0193] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the disclosure herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this application are indicated by the following claims.
[0194] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this 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 disposed on one side of the first electrode, and the second electrode is disposed 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, and some of the sub-light-emitting layers contain a material with thermally activated delayed fluorescence properties. The three sub-light-emitting layers are spaced apart and disposed 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; The first luminescent layer further includes sub-electron blocking layers; the number of sub-electron blocking layers is the same as the number of sub-luminescent layers that do not contain materials with thermally activated delayed fluorescence properties; The area of the sub-electron blocking layer is greater than or equal to the area of the sub-emitting layer that does not contain materials with thermally activated delayed fluorescence characteristics; the sub-electron blocking layers are disposed one-to-one below the sub-emitting layers that do not contain materials with thermally activated delayed fluorescence characteristics and between the sub-emitting layers that do not contain materials with thermally activated delayed fluorescence characteristics and the first common electron blocking layer. The sub-electron blocking layer includes a red electron blocking layer, and the sub-electron emitting layer includes a red emitting layer; the red electron blocking layer includes a first blocking layer and a second blocking layer; the first blocking layer and the second blocking layer are stacked to form the red electron blocking layer.
2. The display panel according to claim 1, characterized in that, The first light-emitting layer further includes auxiliary light-emitting layers, the number of which is less than or equal to the number of sub-light-emitting layers containing materials with thermally activated delayed fluorescence properties, and the area of the auxiliary light-emitting layers is greater than or equal to the area of the sub-light-emitting layers containing materials with thermally activated delayed fluorescence properties; the auxiliary light-emitting layers are disposed one-to-one below the sub-light-emitting layers containing materials with thermally activated delayed fluorescence properties and between the sub-light-emitting layers containing materials with thermally activated delayed fluorescence properties and the first common electron blocking layer.
3. The display panel according to claim 2, characterized in that, The thickness of the auxiliary light-emitting layer is less than the thickness of the corresponding sub-light-emitting layer; the auxiliary light-emitting layer comprises a light-emitting host material and a material with thermally activated delayed fluorescence properties, and the light-emitting host material and the material with thermally activated delayed fluorescence properties are the same as the material of the sub-light-emitting layer corresponding to the auxiliary light-emitting layer.
4. The display panel according to claim 2, characterized in that, The sub-emitting layer includes the red light emitting layer, the green light emitting layer, and the blue light emitting layer, wherein only the green light emitting layer contains a material with thermally activated delayed fluorescence characteristics; the sub-electron blocking layer includes the red light electron blocking layer and the blue light electron blocking layer, which are respectively disposed below the red light emitting layer and the blue light emitting layer; the auxiliary emitting layer includes a green auxiliary emitting layer, which is disposed below the green light emitting layer; the first excited triplet energy level value of the first shared 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.
5. The display panel according to claim 4, characterized in that, The first shared electron blocking layer is made of hole-type carbazole or aromatic amine derivatives, and the thickness of the first shared electron blocking layer is less than or equal to 10 nm.
6. The display panel according to claim 4, characterized in that, The highest occupied molecular orbital value of the blue electron blocking layer is greater than that of the blue light emitting layer, but less than that of the first hole transport layer; the S1 value of the blue electron blocking layer is greater than that of the singlet excited state value of the blue light emitting layer.
7. The display panel according to claim 4, characterized in that, The absolute values of the highest occupied molecular orbital value of the first shared electron blocking layer and the highest occupied molecular orbital value of the first hole transport layer, the absolute values of the highest occupied molecular orbital value of the first shared electron blocking layer and the highest occupied molecular orbital value of the blue electron blocking layer, and the absolute values of the highest occupied molecular orbital value of the first shared electron blocking layer and the highest occupied molecular orbital value of the red electron blocking layer are all less than or equal to 0.25 eV.
8. 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 the 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.
9. The display panel according to any one of claims 1-8, characterized in that, The light-emitting structure further includes a charge-generating structure and a second light-emitting unit; the charge-generating structure is disposed on the side of the first light-emitting unit facing away from the first electrode; the second light-emitting unit is disposed on the side of the charge-generating structure facing away from the first electrode.
10. The display panel according to claim 9, 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 containing a material with thermally activated delayed fluorescence properties.
11. The display panel according to claim 9, 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 disposed on the side of the first light-emitting unit facing away from the first electrode; the P-type charge generation layer is disposed on the side of the N-type charge generation layer facing away from the first electrode.
12. The display panel according to claim 9, characterized in that, The light-emitting structure further 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 disposed between the first hole transport layer and the first electrode; the electron injection layer is disposed between the first electron transport layer and the second electrode.
13. A display device, characterized in that, Includes the display panel as described in any one of claims 1-12.
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