Organic light-emitting device, preparation method thereof and display panel

Abstract

The embodiment of the invention provides an organic light-emitting device, a preparation method thereof and a display panel, and relates to the technical field of display. The organic light-emitting device comprises an electron blocking layer, a light-emitting layer and a hole blocking layer, the light-emitting layer is located on one side of the electron blocking layer, the hole blocking layer is located on the side, away from the electron blocking layer, of the light-emitting layer, and the light-emitting layer comprises a first light-emitting sub-layer making contact with the electron blocking layer and a second light-emitting sub-layer making contact with the hole blocking layer. At most one of the first sub-emission layer and the second sub-emission layer includes a phosphorescent material. According to the embodiment, the interface, close to the electron blocking layer or the hole blocking layer, of the light-emitting layer is not doped with the phosphorescent material, so that the number of excitons at the interface of the light-emitting layer is reduced, the degradation of the material at the interface of the light-emitting layer caused by high-energy excitons is reduced, and the excitons at any interface of the light-emitting layer can be independently regulated and controlled; the optimization of two light-emitting layers with more holes or more electrons is realized in a targeted manner, and the light-emitting efficiency and the service life of the organic light-emitting device are improved and prolonged.

Description

Technical Field

[0001] The present application relates to the field of display technologies, and particularly to an organic electroluminescent device, a preparation method thereof, and a display panel. Background Art

[0002] An organic light emitting diode (OLED) is a device that emits light by current driving. Specifically, the organic electroluminescent device includes functional layers such as a cathode layer, an anode layer, and a light emitting layer located between the cathode layer and the anode layer. When a voltage is applied, electrons from the cathode layer and holes from the anode layer will migrate to the light emitting layer and combine to generate excitons, and then emit light of different wavelengths according to the characteristics of the light emitting layer.

[0003] However, the existing organic electroluminescent devices have poor luminous efficiency. Summary of the Invention

[0004] In view of this, embodiments of the present application provide an organic electroluminescent device, a preparation method thereof, and a display panel to solve the problem of poor luminous efficiency of existing organic electroluminescent devices.

[0005] In a first aspect of the present application, an organic electroluminescent device is provided, which includes an electron blocking layer, a light emitting layer, and a hole blocking layer. The light emitting layer is located on one side of the electron blocking layer, and the hole blocking layer is located on the side of the light emitting layer away from the electron blocking layer. Among them, the light emitting layer includes a first sub-light emitting layer in contact with the electron blocking layer and a second sub-light emitting layer in contact with the hole blocking layer, and at most one of the first sub-light emitting layer and the second sub-light emitting layer includes a phosphorescent material.

[0006] In one embodiment, the first sub-light emitting layer includes a host material, a fluorescent material, and a phosphorescent material; preferably, the second sub-light emitting layer includes a host material; preferably, the second sub-light emitting layer includes a host material and a fluorescent material; preferably, the thickness of the second sub-light emitting layer is greater than or equal to 1 nanometer and less than or equal to 5 nanometers.

[0007] In one embodiment, the second sub-light emitting layer includes a host material, a fluorescent material, and a phosphorescent material; preferably, the first sub-light emitting layer includes a host material; preferably, the first sub-light emitting layer includes a host material and a fluorescent material; preferably, the thickness of the first sub-light emitting layer is greater than or equal to 1 nanometer and less than or equal to 5 nanometers.

[0008] In one embodiment, the light-emitting layer further includes a third sub-light-emitting layer located between the first sub-light-emitting layer and the second sub-light-emitting layer. The third sub-light-emitting layer includes a host material, a fluorescent material, and a phosphorescent material. Preferably, one of the first sub-light-emitting layer and the second sub-light-emitting layer includes a phosphorescent material. Preferably, neither the first sub-light-emitting layer nor the second sub-light-emitting layer includes a phosphorescent material. Preferably, the host material includes a blue host material. Preferably, the phosphorescent material includes a blue phosphorescent material. Preferably, the fluorescent material includes a blue fluorescent material. Preferably, the light-emitting layer includes a blue light-emitting layer. Preferably, the light-emitting layer is at least one of a green light-emitting layer, a red light-emitting layer, and a yellow light-emitting layer.

[0009] In one embodiment, the first sub-light-emitting layer includes a host material, and the second sub-light-emitting layer includes a host material; or, the first sub-light-emitting layer includes a host material, and the second sub-light-emitting layer includes a host material and a fluorescent material; or, the first sub-light-emitting layer includes a host material, and the second sub-light-emitting layer includes a host material, a fluorescent material, and a phosphorescent material; or, the first sub-light-emitting layer includes a host material and a fluorescent material, and the second sub-light-emitting layer includes a host material; or, the first sub-light-emitting layer includes a host material and a fluorescent material, and the second sub-light-emitting layer includes a host material and a fluorescent material; or, the first sub-light-emitting layer includes a host material, a fluorescent material, and a phosphorescent material, and the second sub-light-emitting layer includes a host material; or, the first sub-light-emitting layer includes a host material, a fluorescent material, and a phosphorescent material, and the second sub-light-emitting layer includes a host material and a fluorescent material; or, the first sub-light-emitting layer includes a host material and a fluorescent material, and the second sub-light-emitting layer includes a host material, a fluorescent material, and a phosphorescent material.

[0010] In one embodiment, the host material includes a first host material and a second host material with different materials. Preferably, the first sub-light-emitting layer includes the first host material, and the second sub-light-emitting layer includes the second host material. Preferably, the first sub-light-emitting layer includes the second host material, and the second sub-light-emitting layer includes the first host material. Preferably, the first host material includes an electron-withdrawing group. Preferably, the second host material includes an electron-donating group.

[0011] In one embodiment, an anode layer and a cathode layer are further included. The anode layer is located on the side of the electron blocking layer away from the light-emitting layer, and the cathode layer is located on the side of the hole blocking layer away from the light-emitting layer. Preferably, a hole injection layer and a hole transport layer are further included between the anode layer and the electron blocking layer. Preferably, an electron transport layer and an electron injection layer are further included between the hole blocking layer and the cathode layer.

[0012] The second aspect of the present application provides a method for manufacturing an organic electroluminescent device, including: sequentially manufacturing an electron blocking layer, a light-emitting layer, and a hole blocking layer on one side of the anode layer, where the light-emitting layer includes a first sub-light-emitting layer in contact with the electron blocking layer and a second sub-light-emitting layer in contact with the hole blocking layer, and at most one of the first sub-light-emitting layer and the second sub-light-emitting layer includes a phosphorescent material; manufacturing a cathode layer on the side of the hole blocking layer facing away from the anode layer.

[0013] In one embodiment, sequentially manufacturing an electron blocking layer, a light-emitting layer, and a hole blocking layer on one side of the anode layer includes: manufacturing an electron blocking layer on one side of the anode layer; placing a host material in a first evaporation source, placing a fluorescent material in a second evaporation source, and placing a phosphorescent material in a third evaporation source; manufacturing the first sub-light-emitting layer and the second sub-light-emitting layer on the side of the electron blocking layer facing away from the anode layer through the first evaporation source, the second evaporation source, and the third evaporation source, where at most one of the first sub-light-emitting layer and the second sub-light-emitting layer includes a phosphorescent material; manufacturing a hole blocking layer on the side of the second light-emitting layer facing away from the anode layer; preferably, evaporating through the first evaporation source, the second evaporation source, and the third evaporation source on the side of the electron blocking layer facing away from the anode layer to form the first sub-light-emitting layer and the second sub-light-emitting layer includes: setting a first evaporation angle range of the first evaporation source, a second evaporation angle range of the second evaporation source, and a third evaporation angle range of the third evaporation source, where the second evaporation angle range is less than or equal to the first evaporation angle range, and the third evaporation angle range is less than the first evaporation angle range; evaporating on the side of the electron blocking layer facing away from the anode layer based on the first evaporation angle range, the second evaporation angle, and the third evaporation angle range to form the first sub-light-emitting layer and the second sub-light-emitting layer, where at most one of the first sub-light-emitting layer and the second sub-light-emitting layer includes a phosphorescent material; preferably, evaporating through the first evaporation source, the second evaporation source, and the third evaporation source on the side of the electron blocking layer facing away from the anode layer to form the first sub-light-emitting layer and the second sub-light-emitting layer includes: setting a first evaporation time of the first evaporation source, a second evaporation time of the second evaporation source, and a third evaporation time of the third evaporation source, where the second evaporation time is less than or equal to the first evaporation time, and the third evaporation time is less than the first evaporation time; evaporating on the side of the electron blocking layer facing away from the anode layer based on the first evaporation time, the second time, and the third evaporation time to form the first sub-light-emitting layer and the second sub-light-emitting layer, where at most one of the first sub-light-emitting layer and the second sub-light-emitting layer includes a phosphorescent material.

[0014] The third aspect of the present application provides a display panel, including the above-mentioned organic electroluminescent device, or including an organic electroluminescent device manufactured by the above-mentioned manufacturing method.

[0015] The organic electroluminescent device, its manufacturing method, and the display panel provided by the embodiments of the present application. The organic electroluminescent device includes an electron blocking layer, a light emitting layer, and a hole blocking layer. The light emitting layer is located on one side of the electron blocking layer, and the hole blocking layer is located on the side of the light emitting layer away from the electron blocking layer. Among them, the light emitting layer includes a first sub-light emitting layer in contact with the electron blocking layer and a second sub-light emitting layer in contact with the hole blocking layer. At most one of the first sub-light emitting layer and the second sub-light emitting layer includes a phosphorescent material. By not doping the phosphorescent material at the interface of the light emitting layer close to the electron blocking layer or the hole blocking layer in the above embodiments, the number of excitons at the interface of the light emitting layer is reduced, and the deterioration of the material at the interface of the light emitting layer by high-energy excitons is reduced. Further, it is also possible to individually control the excitons at any interface of the light emitting layer, and specifically optimize the two types of light emitting layers with more holes or more electrons, thereby improving the luminous efficiency and lifespan of the organic electroluminescent device. Description of the Drawings

[0016] Figure 1 It is a schematic structural diagram of the organic electroluminescent device provided by the first embodiment of the present application.

[0017] Figure 2 It is a schematic structural diagram of the organic electroluminescent device provided by the second embodiment of the present application.

[0018] Figure 3 It is a schematic structural diagram of the organic electroluminescent device provided by the third embodiment of the present application.

[0019] Figure 4 It is a schematic structural diagram of the organic electroluminescent device provided by the fourth embodiment of the present application.

[0020] Figure 5 It is a schematic structural diagram of the organic electroluminescent device provided by the fifth embodiment of the present application.

[0021] Figure 6 It is a schematic structural diagram of the organic electroluminescent device provided by the sixth embodiment of the present application.

[0022] Figure 7 It is a schematic flowchart of the manufacturing method of the organic electroluminescent device provided by the first embodiment of the present application.

[0023] Figure 8 It is a schematic flowchart of the manufacturing method of the organic electroluminescent device provided by the second embodiment of the present application.

[0024] Figure 9 is Figure 8 a schematic structural diagram of the manufacturing method of the organic electroluminescent device shown.

[0025] Figure 10 It is a schematic structural diagram of the display panel provided by the embodiments of the present application. Detailed Implementation Manner

[0026] An organic light emitting diode (OLED) is a device that achieves light emission through current driving. Specifically, an organic light emitting diode includes functional layers such as a cathode layer, an anode layer, and a light emitting layer located between the cathode layer and the anode layer. When a voltage is applied, electrons from the cathode layer and holes from the anode layer will migrate to the light emitting layer respectively and combine to generate excitons, and then emit light of different wavelengths according to the characteristics of the light emitting layer. The light emitting efficiency of existing organic light emitting diodes is poor.

[0027] In view of this, the organic light emitting diode, its manufacturing method, and a display panel provided in the embodiments of the present application. The organic light emitting diode includes an electron blocking layer, a light emitting layer, and a hole blocking layer. The light emitting layer is located on one side of the electron blocking layer, and the hole blocking layer is located on the side of the light emitting layer away from the electron blocking layer. Among them, the light emitting layer includes a first sub-light emitting layer in contact with the electron blocking layer and a second sub-light emitting layer in contact with the hole blocking layer. At most one of the first sub-light emitting layer and the second sub-light emitting layer includes a phosphorescent material. By not doping the phosphorescent material at the interface of the light emitting layer close to the electron blocking layer or the hole blocking layer in the above embodiments, the number of excitons at the interface of the light emitting layer is reduced, and the deterioration of the material at the interface of the light emitting layer caused by high-energy excitons is reduced. Further, it is also possible to separately regulate the excitons at any interface of the light emitting layer, and specifically optimize the two types of light emitting layers with more holes or more electrons, so as to improve the light emitting efficiency and lifespan of the organic light emitting diode.

[0028] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0029] In addition, in order to better illustrate the present application, numerous specific details are given in the following detailed implementation manners. Those skilled in the art should understand that the present application can be implemented without some specific details. In some instances, methods and means well known to those skilled in the art are not described in detail in order to highlight the gist of the present application.

[0030] It should be noted that similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0031] In addition, if terms such as "first" and "second" appear, they are only used for distinguishing descriptions and cannot be understood as indicating or implying relative importance.

[0032] Figure 1 is a schematic structural view of an organic electroluminescent device provided by the first embodiment of the present application. As Figure 1 shown, the organic electroluminescent device includes an electron blocking layer 10, a light-emitting layer 20, and a hole blocking layer 30. The light-emitting layer 20 is located on one side of the electron blocking layer 10, and the hole blocking layer 30 is located on the side of the light-emitting layer 20 away from the electron blocking layer 10. Among them, the light-emitting layer 20 includes a first sub-light-emitting layer 21 and a second sub-light-emitting layer 22. The first sub-light-emitting layer 21 is in contact with the electron blocking layer 10, and the second sub-light-emitting layer 22 is in contact with the hole blocking layer 30. At most one of the first sub-light-emitting layer 21 and the second sub-light-emitting layer 22 includes a phosphorescent material.

[0033] In the above embodiment, by not doping the phosphorescent material at the interface of the light-emitting layer close to the electron blocking layer or the hole blocking layer, the number of excitons at the interface of the light-emitting layer is reduced, and the deterioration of the material at the interface of the light-emitting layer caused by high-energy excitons is reduced. Further, it is also possible to separately control the excitons at any interface of the light-emitting layer, and specifically optimize the two types of light-emitting layers with more holes or more electrons, thereby improving the luminous efficiency and lifespan of the organic electroluminescent device.

[0034] Optionally, the electron blocking layer 10 can control the flow direction of electrons in the organic electroluminescent device.

[0035] Optionally, the hole blocking layer 30 can control the flow direction of holes in the organic electroluminescent device.

[0036] Optionally, in one embodiment, the light-emitting layer 20 may include a host material, a fluorescent material, and a phosphorescent material.

[0037] In an organic electroluminescent device, the product power consumption mainly accounts for the luminous power consumption of the light-emitting device, and among different pixels, the power consumption ratio of the blue light-emitting layer is the largest. Therefore, improving the luminous efficiency of the blue light-emitting layer is one of the main ways to reduce the product power consumption of the organic electroluminescent device.

[0038] Optionally, in one embodiment, the host material may include a blue host material.

[0039] Optionally, in one embodiment, the phosphorescent material may include a blue phosphorescent material.

[0040] Optionally, in one embodiment, the fluorescent material may include a blue fluorescent material.

[0041] Optionally, in one embodiment, the light-emitting layer 20 may include a blue light-emitting layer.

[0042] It should be understood that although improving the luminous efficiency of the blue light-emitting layer is one of the main ways to reduce the product power consumption of the organic electroluminescent device, improving the luminous efficiency of the green light-emitting layer, red light-emitting layer or yellow light-emitting layer can also reduce the product power consumption of the organic electroluminescent device.

[0043] Optionally, in one embodiment, the host material may be at least one of a green host material, a red host material, and a yellow host material.

[0044] Optionally, in one embodiment, the phosphorescent material may include at least one of a green phosphorescent material, a red phosphorescent material, and a yellow phosphorescent material.

[0045] Optionally, in one embodiment, the fluorescent material may include at least one of a green fluorescent material, a red fluorescent material, and a yellow fluorescent material.

[0046] Optionally, in one embodiment, the light-emitting layer 20 may be at least one of a green light-emitting layer, a red light-emitting layer, and a yellow light-emitting layer.

[0047] Optionally, the host material includes a thermally activated delayed fluorescence material (Thermally Activated Delayed Fluorescence, TADF).

[0048] Specifically, in the phosphor-assisted TADF-sensitized fluorescence (pTSF) technology, the phosphor sensitizer transfers the exciton energy to the fluorescent material to make the fluorescent material emit light. In this application, by setting the TADF host and the phosphor sensitizer, the excitons in the organic electroluminescent device are fully utilized, and the utilization rate can reach 100%.

[0049] Optionally, in one embodiment, the light-emitting layer 20 includes two sub-light-emitting layers. Specifically, the light-emitting layer 20 includes a first sub-light-emitting layer 21 and a second sub-light-emitting layer 22.

[0050] Optionally, in one embodiment, the first sub-light-emitting layer 21 includes a phosphorescent material, and the second sub-light-emitting layer 22 does not include a phosphorescent material.

[0051] At this time, the thickness W2 of the second sub-light-emitting layer 22 is greater than or equal to 1 nanometer and less than or equal to 5 nanometers. For example, the thickness W2 of the second sub-light-emitting layer 22 may be 1 nanometer, 3 nanometers, 5 nanometers, etc., and can be matched with light-emitting layers and transport layers with different properties (such as an electron transport layer, a hole transport layer, etc.) to optimize the lifespan of the organic electroluminescent device.

[0052] Specifically, in one embodiment, the first sub-emitting layer 21 may include a host material, a fluorescent material, and a phosphorescent material, and the second sub-emitting layer 22 may include a host material.

[0053] Specifically, in another embodiment, the second sub-emitting layer 22 may include a host material, a fluorescent material, and a phosphorescent material, and the second sub-emitting layer 22 may include a host material and a fluorescent material.

[0054] Figure 2 It is a schematic structural diagram of an organic electroluminescent device provided in the second embodiment of the present application. As Figure 2 shown Figure 2 The difference between the shown organic electroluminescent device and Figure 1 the shown organic electroluminescent device is that Figure 2 in the organic electroluminescent device, the first sub-emitting layer 21 does not include a phosphorescent material, and the second sub-emitting layer 22 includes a phosphorescent material.

[0055] At this time, the thickness W1 of the first sub-emitting layer 21 is greater than or equal to 1 nanometer and less than or equal to 5 nanometers. For example, the thickness W1 of the first sub-emitting layer 21 may be 1 nanometer, 3 nanometers, 5 nanometers, etc., and can be matched with light-emitting layers and transport layers (such as electron transport layers, hole transport layers, etc.) of different properties to optimize the lifespan of the organic electroluminescent device.

[0056] Specifically, in one embodiment, the second sub-emitting layer 22 may include a host material, a fluorescent material, and a phosphorescent material, and the first sub-emitting layer 21 may include a host material.

[0057] Specifically, in another embodiment, the second sub-emitting layer 22 may include a host material, a fluorescent material, and a phosphorescent material, and the first sub-emitting layer 21 may include a host material and a fluorescent material.

[0058] Figure 3 It is a schematic structural diagram of an organic electroluminescent device provided in the third embodiment of the present application. As Figure 3 shown, Figure 3 The difference between the shown organic electroluminescent device and Figure 1 the shown organic electroluminescent device is that Figure 3 in the shown organic electroluminescent device, the light-emitting layer 20 includes three sub-emitting layers. Specifically, the light-emitting layer 20 further includes a third sub-emitting layer 23, that is, the light-emitting layer 20 includes the first sub-emitting layer 21, the second sub-emitting layer 22, and the third sub-emitting layer 23, where the third sub-emitting layer 23 is located between the first sub-emitting layer 21 and the second sub-emitting layer 22.

[0059] Optionally, in one embodiment, the third sub-emitting layer 23 includes a phosphorescent material, and one of the first sub-emitting layer 21 and the second sub-emitting layer 22 includes a phosphorescent material.

[0060] Optionally, in one embodiment, the third sub-light-emitting layer 23 and the first sub-light-emitting layer 21 include phosphorescent materials, and the second sub-light-emitting layer 22 does not include phosphorescent materials.

[0061] At this time, the thickness W2 of the second sub-light-emitting layer 22 is greater than or equal to 1 nm and less than or equal to 5 nm. For example, the thickness W2 of the second sub-light-emitting layer 22 can be 1 nm, 3 nm, 5 nm, etc., and it can be matched with light-emitting layers and transport layers of different properties to optimize the lifetime of the organic electroluminescent device.

[0062] Specifically, in one embodiment, the third sub-light-emitting layer 23 includes a host material, a fluorescent material, and a phosphorescent material, the first sub-light-emitting layer 21 includes a host material, a fluorescent material, and a phosphorescent material, and the second sub-light-emitting layer 22 includes a host material.

[0063] Specifically, in another embodiment, the third sub-light-emitting layer 23 includes a host material, a fluorescent material, and a phosphorescent material, the first sub-light-emitting layer 21 includes a host material, a fluorescent material, and a phosphorescent material, and the second sub-light-emitting layer 22 includes a host material and a fluorescent material.

[0064] Figure 4 It is a schematic structural diagram of an organic electroluminescent device provided by the fourth embodiment of the present application. As Figure 4 shown, Figure 4 The difference between the shown organic electroluminescent device and Figure 3 the shown organic electroluminescent device is that Figure 4 in the shown organic electroluminescent device, the third sub-light-emitting layer 23 and the second sub-light-emitting layer 22 include phosphorescent materials, and the first sub-light-emitting layer 21 does not include phosphorescent materials.

[0065] At this time, the thickness W1 of the first sub-light-emitting layer 21 is greater than or equal to 1 nm and less than or equal to 5 nm. For example, the thickness W1 of the first sub-light-emitting layer 21 can be 1 nm, 3 nm, 5 nm, etc., and it can be matched with light-emitting layers and transport layers of different properties to optimize the lifetime of the organic electroluminescent device.

[0066] Specifically, in one embodiment, the third sub-light-emitting layer 23 includes a host material, a fluorescent material, and a phosphorescent material, the second sub-light-emitting layer 22 includes a host material, a fluorescent material, and a phosphorescent material, and the first sub-light-emitting layer 21 includes a host material.

[0067] Specifically, in another embodiment, the third sub-light-emitting layer 23 includes a host material, a fluorescent material, and a phosphorescent material, the second sub-light-emitting layer 22 includes a host material, a fluorescent material, and a phosphorescent material, and the first sub-light-emitting layer 21 includes a host material and a fluorescent material.

[0068] Figure 5It is a schematic structural diagram of an organic electroluminescent device provided by the fifth embodiment of the present application. As Figure 5 shown, Figure 5 the difference between the organic electroluminescent device shown and Figure 3 the organic electroluminescent device shown is that Figure 5 in the organic electroluminescent device shown, the third sub-emitting layer 23 includes a phosphorescent material, and neither the first sub-emitting layer 21 nor the second sub-emitting layer 22 includes a phosphorescent material.

[0069] At this time, the thickness W1 of the first sub-emitting layer 21 is greater than or equal to 1 nanometer and less than or equal to 5 nanometers. For example, the thickness W1 of the first sub-emitting layer 21 can be 1 nanometer, 3 nanometers, 5 nanometers, etc., and can be matched with light-emitting layers and transport layers of different properties to optimize the lifespan of the organic electroluminescent device.

[0070] And the thickness W2 of the second sub-emitting layer 22 is greater than or equal to 1 nanometer and less than or equal to 5 nanometers. For example, the thickness W2 of the second sub-emitting layer 22 can be 1 nanometer, 3 nanometers, 5 nanometers, etc., and can be matched with light-emitting layers and transport layers of different properties to optimize the lifespan of the organic electroluminescent device.

[0071] Specifically, in one embodiment, the third sub-emitting layer 23 includes a host material, a fluorescent material, and a phosphorescent material, the first sub-emitting layer 21 includes a host material, and the second sub-emitting layer 22 includes a host material.

[0072] Specifically, in another embodiment, the third sub-emitting layer 23 includes a host material, a fluorescent material, and a phosphorescent material, the first sub-emitting layer 21 includes a host material and a fluorescent material, and the second sub-emitting layer 22 includes a host material.

[0073] Specifically, in yet another embodiment, the third sub-emitting layer 23 includes a host material, a fluorescent material, and a phosphorescent material, the first sub-emitting layer 21 includes a host material, and the second sub-emitting layer 22 includes a host material and a fluorescent material.

[0074] Specifically, in still another embodiment, the third sub-emitting layer 23 includes a host material, a fluorescent material, and a phosphorescent material, the first sub-emitting layer 21 includes a host material and a fluorescent material, and the second sub-emitting layer 22 includes a host material and a fluorescent material.

[0075] Optionally, in one embodiment, in order to better adapt to the electron blocking layer 10 and the hole blocking layer 30, the host material may include a first host material and a second host material with different materials, which can improve the distribution of the recombination region of the light-emitting layer 20, improve the distribution of high-energy excitons at the interface of the light-emitting layer 20, and improve the light-emitting efficiency and lifespan of the organic electroluminescent device.

[0076] Optionally, in one embodiment, the first host material includes an electron-withdrawing group.

[0077] Optionally, in one embodiment, the second host material includes an electron-donating group.

[0078] Optionally, in one embodiment, the third sub-emitting layer 23 includes a first host material, a second host material, a phosphorescent material, and a fluorescent material.

[0079] Specifically, in one embodiment, the first sub-emitting layer 21 includes at least the first host material, and the second sub-emitting layer 22 includes at least the second host material.

[0080] For example, the third sub-emitting layer 23 includes a first host material, a second host material, a fluorescent material, and a phosphorescent material, the first sub-emitting layer 21 includes a first host material, a fluorescent material, and a phosphorescent material, and the second sub-emitting layer 22 includes the second host material.

[0081] For example, the third sub-emitting layer 23 includes a first host material, a second host material, a fluorescent material, and a phosphorescent material, the first sub-emitting layer 21 includes a first host material, a fluorescent material, and a phosphorescent material, and the second sub-emitting layer 22 includes the second host material and a fluorescent material.

[0082] For example, the third sub-emitting layer 23 includes a first host material, a second host material, a fluorescent material, and a phosphorescent material, the second sub-emitting layer 22 includes the second host material, a fluorescent material, and a phosphorescent material, and the first sub-emitting layer 21 includes the first host material.

[0083] For example, the third sub-emitting layer 23 includes a first host material, a second host material, a fluorescent material, and a phosphorescent material, the second sub-emitting layer 22 includes the second host material, a fluorescent material, and a phosphorescent material, and the first sub-emitting layer 21 includes the first host material and a fluorescent material.

[0084] For example, the third sub-emitting layer 23 includes a first host material, a second host material, a fluorescent material, and a phosphorescent material, the first sub-emitting layer 21 includes the first host material, and the second sub-emitting layer 22 includes the second host material.

[0085] For example, the third sub-emitting layer 23 includes a first host material, a second host material, a fluorescent material, and a phosphorescent material, the first sub-emitting layer 21 includes the first host material and a fluorescent material, and the second sub-emitting layer 22 includes the second host material.

[0086] For example, the third sub-emitting layer 23 includes a first host material, a second host material, a fluorescent material, and a phosphorescent material, the first sub-emitting layer 21 includes the first host material, and the second sub-emitting layer 22 includes the second host material and a fluorescent material.

[0087] For example, the third sub-light-emitting layer 23 includes a first host material, a second host material, a fluorescent material, and a phosphorescent material. The first sub-light-emitting layer 21 includes a first host material and a fluorescent material. The second sub-light-emitting layer 22 includes a second host material and a fluorescent material.

[0088] Specifically, in one embodiment, the first sub-light-emitting layer 21 includes the second host material, and the second sub-light-emitting layer 22 includes the first host material.

[0089] For example, the third sub-light-emitting layer 23 includes a first host material, a second host material, a fluorescent material, and a phosphorescent material. The first sub-light-emitting layer 21 includes the second host material, a fluorescent material, and a phosphorescent material. The second sub-light-emitting layer 22 includes the first host material.

[0090] For example, the third sub-light-emitting layer 23 includes a first host material, a second host material, a fluorescent material, and a phosphorescent material. The first sub-light-emitting layer 21 includes the second host material, a fluorescent material, and a phosphorescent material. The second sub-light-emitting layer 22 includes the first host material and a fluorescent material.

[0091] For example, the third sub-light-emitting layer 23 includes a first host material, a second host material, a fluorescent material, and a phosphorescent material. The second sub-light-emitting layer 22 includes the first host material, a fluorescent material, and a phosphorescent material. The first sub-light-emitting layer 21 includes the second host material.

[0092] For example, the third sub-light-emitting layer 23 includes a first host material, a second host material, a fluorescent material, and a phosphorescent material. The second sub-light-emitting layer 22 includes the first host material, a fluorescent material, and a phosphorescent material. The first sub-light-emitting layer 21 includes the second host material and a fluorescent material.

[0093] For example, the third sub-light-emitting layer 23 includes a first host material, a second host material, a fluorescent material, and a phosphorescent material. The first sub-light-emitting layer 21 includes the second host material, and the second sub-light-emitting layer 22 includes the first host material.

[0094] For example, the third sub-light-emitting layer 23 includes a first host material, a second host material, a fluorescent material, and a phosphorescent material. The first sub-light-emitting layer 21 includes the second host material and a fluorescent material. The second sub-light-emitting layer 22 includes the first host material.

[0095] For example, the third sub-light-emitting layer 23 includes a first host material, a second host material, a fluorescent material, and a phosphorescent material. The first sub-light-emitting layer 21 includes the second host material, and the second sub-light-emitting layer 22 includes the first host material and a fluorescent material.

[0096] For example, the third sub-light-emitting layer 23 includes a first host material, a second host material, a fluorescent material, and a phosphorescent material. The first sub-light-emitting layer 21 includes the second host material and a fluorescent material. The second sub-light-emitting layer 22 includes the first host material and a fluorescent material.

[0097] Comparative Example

[0098] The first sub-emissive layer 21 includes a host material, a phosphorescent material, and a fluorescent material, and the second sub-emissive layer 22 includes a host material, a phosphorescent material, and a fluorescent material. The organic electroluminescent device of the embodiment of the present application and the organic electroluminescent device of the comparative example are compared in terms of performance, and the results are shown in Table 1.

[0099] Table 1

[0100] Service life Efficiency Embodiment of the present application ＞102％ ＞120％ Comparative example 100％ 100％

[0101] According to the statistical results in Table 1, it can be seen that the lifespan of the organic electroluminescent device provided by the embodiment of the present application is higher than that of the organic electroluminescent device provided by the comparative example, and the efficiency of the organic electroluminescent device provided by the embodiment of the present application is greater than that of the organic electroluminescent device provided by the comparative example. This shows that the technical solution of the present application can effectively improve the lifespan and luminous efficiency of the organic electroluminescent device.

[0102] Figure 6 It is a schematic structural diagram of the organic electroluminescent device provided by the sixth embodiment of the present application. As Figure 6 shown, in one embodiment, the organic electroluminescent device further includes an anode layer 40 and a cathode layer 50. The anode layer 40 is located on the side of the electron blocking layer 10 away from the emissive layer 20, and the cathode layer 50 is located on the side of the hole blocking layer 30 away from the emissive layer 20.

[0103] Optionally, in one embodiment, the organic electroluminescent device further includes a hole injection layer 60 and / or a hole transport layer 70 located between the anode layer 40 and the electron blocking layer 10. The hole injection layer 60 is used to reduce the potential barrier between the anode layer 40 and the hole transport layer 70 and promote the efficient injection of holes from the anode layer 40. The hole transport layer 70 transports holes to the emissive layer 20.

[0104] Optionally, in one embodiment, the organic electroluminescent device further includes an electron transport layer 80 and / or an electron injection layer 90 located between the hole blocking layer 30 and the cathode layer 50. The electron injection layer 90 is used to reduce the potential barrier between the cathode layer 50 and the electron transport layer 80 and promote the efficient injection of electrons from the cathode layer 50. The electron transport layer 80 transports electrons to the emissive layer 20.

[0105] The present application also provides a method for manufacturing an organic electroluminescent device, Figure 7 which is a schematic flow diagram of the method for manufacturing an organic electroluminescent device provided by the first embodiment of the present application. As Figure 7 shown, the manufacturing method includes:

[0106] Step S100, sequentially fabricating an electron blocking layer, an emissive layer, and a hole blocking layer on one side of the anode layer.

[0107] Among them, the light-emitting layer 20 includes a first sub-light-emitting layer 21 and a second sub-light-emitting layer 22. The first sub-light-emitting layer 21 is in contact with the electron blocking layer 10, and the second sub-light-emitting layer 22 is in contact with the hole blocking layer 30. At most one of the first sub-light-emitting layer 21 and the second sub-light-emitting layer 22 includes a phosphorescent material.

[0108] Step S200: Prepare a cathode layer on the side of the hole blocking layer away from the anode layer.

[0109] Among them, the cathode layer may include a magnesium (Mg)-silver (Ag) alloy, or a transparent metal oxide such as indium zinc oxide (IZO). In this embodiment, the Mg-Ag alloy is used as the cathode.

[0110] Figure 8 It is a schematic flowchart of a method for manufacturing an organic electroluminescent device provided in the second embodiment of the present application. As Figure 8 shown, sequentially preparing an electron blocking layer, a light-emitting layer, and a hole blocking layer on one side of the anode layer (step S100) includes:

[0111] Step S110: Prepare an electron blocking layer on one side of the anode layer.

[0112] Among them, the electron blocking layer 10 can control the flow direction of electrons in the organic electroluminescent device.

[0113] Step S120: Place the host material in the first evaporation source, place the fluorescent material in the second evaporation source, and place the phosphorescent material in the third evaporation source.

[0114] Among them, the host material includes a thermally activated delayed fluorescence material.

[0115] Step S130: Prepare a first sub-light-emitting layer and a second sub-light-emitting layer on the side of the electron blocking layer away from the anode layer through the first evaporation source, the second evaporation source, and the third evaporation source.

[0116] As a way, preparing a first sub-light-emitting layer and a second sub-light-emitting layer on the side of the electron blocking layer away from the anode layer through the first evaporation source, the second evaporation source, and the third evaporation source includes:

[0117] Set the first evaporation angle range of the first evaporation source, the second evaporation angle range of the second evaporation source, and the third evaporation angle range of the third evaporation source. Among them, the second evaporation angle range is less than or equal to the first evaporation angle range, and the third evaporation angle range is less than the first evaporation angle range.

[0118] Evaporation is performed on the side of the electron blocking layer facing away from the anode layer based on a first evaporation angle range, a second evaporation angle, and a third evaporation angle range to form a first sub-light-emitting layer and a second sub-light-emitting layer, wherein at most one of the first sub-light-emitting layer and the second sub-light-emitting layer includes a phosphorescent material.

[0119] For example, Figure 9 is Figure 8 a schematic structural diagram of a method for manufacturing an organic electroluminescent device as shown. As Figure 9 shown, the first evaporation angle range of the first evaporation source 101 is the same as the second evaporation angle range of the second evaporation source 102, and the third evaporation angle range of the third evaporation source 103 is smaller. When the first evaporation source 101, the second evaporation source 102, and the third evaporation source 103 move towards the electron blocking layer 10, the evaporation materials of the first evaporation source 101 and the second evaporation source 102 first contact the electron blocking layer 10 to form a first sub-light-emitting layer 21 mixed with a host material and a fluorescent material. The evaporation material of the third evaporation source 103 can only be evaporated on the first sub-light-emitting layer 21 and, together with the evaporation materials of the first evaporation source 101 and the second evaporation source 102, forms a second sub-light-emitting layer 22 mixed with a host material, a fluorescent material, and a phosphorescent material, finally forming a first sub-light-emitting layer 21 including a host material and a fluorescent material and a second sub-light-emitting layer 22 including a host material, a fluorescent material, and a phosphorescent material.

[0120] As one way, preparing the first sub-light-emitting layer and the second sub-light-emitting layer on the side of the electron blocking layer facing away from the anode layer by the first evaporation source, the second evaporation source, and the third evaporation source includes:

[0121] Setting a first evaporation time of the first evaporation source, a second evaporation time of the second evaporation source, and a third evaporation time of the third evaporation source, wherein the second evaporation time is less than or equal to the first evaporation time, and the third evaporation time is less than the first evaporation time.

[0122] Evaporation is performed on the side of the electron blocking layer facing away from the anode layer based on the first evaporation time, the second time, and the third evaporation time to form a first sub-light-emitting layer and a second sub-light-emitting layer, wherein at most one of the first sub-light-emitting layer and the second sub-light-emitting layer includes a phosphorescent material.

[0123] For example, the first evaporation time of the first evaporation source 101 is the same as the second evaporation time of the second evaporation source 102, and the third evaporation time of the third evaporation source 103 is shorter. That is, the first evaporation source 101 and the second evaporation source 102 are turned on first, and the evaporation materials of the first evaporation source 101 and the second evaporation source 102 first contact the electron blocking layer 10 to form the first sub-light-emitting layer 21 mixed with the host material and the fluorescent material. Then, the third evaporation source 103 is turned on, and the evaporation material of the third evaporation source 103 can only be evaporated on the first sub-light-emitting layer 21, and together with the evaporation materials of the first evaporation source 101 and the second evaporation source 102, form the second sub-light-emitting layer 22 mixed with the host material, the fluorescent material, and the phosphorescent material. Finally, the first sub-light-emitting layer 21 including the host material and the fluorescent material and the second sub-light-emitting layer 22 including the host material, the fluorescent material, and the phosphorescent material are formed.

[0124] Step S140: Prepare a hole blocking layer on the side of the second light-emitting layer away from the anode layer.

[0125] Among them, the hole blocking layer 30 can control the flow direction of holes in the organic electroluminescent device.

[0126] An embodiment of the present application also provides a display panel. Figure 10 It is a schematic structural diagram of the display panel provided by the embodiment of the present application. As Figure 10 shown, the display panel includes the organic electroluminescent device provided by the above embodiment.

[0127] Optionally, in one embodiment, the display panel includes a substrate 210, a pixel definition layer 220, and at least one organic electroluminescent device 100. The pixel definition layer 220 is located on one side of the substrate 210. The pixel definition layer 220 encloses a pixel opening Q, and at least a part of the organic electroluminescent device 100 is located within the pixel opening Q.

[0128] The display panel provided according to any embodiment of the present application and the organic electroluminescent device provided by the embodiment of the present application belong to the same inventive concept and have corresponding film layer structures and beneficial effects. Details not described in detail in the embodiment of the display panel can be found in the embodiment part of the organic electroluminescent device, and will not be elaborated here.

[0129] An embodiment of the present application also provides a display device. The display device includes the display panel provided by the above embodiment. The display device is a product with an image display function. For example, the display device can be used to display static images, such as pictures or photos. The display device can also be used to display dynamic images, such as videos.

[0130] In addition, the display device can also have functions such as taking pictures, recording videos, fingerprint recognition, and face recognition. Correspondingly, the display device further includes at least one functional module for implementing the above functions, such as an under-screen camera, an under-screen fingerprint recognition sensor, etc.

[0131] The display device provided according to any embodiment of the present application and the display panel provided by the embodiments of the present application belong to the same inventive concept and have corresponding film layer structures and beneficial effects. Details not described in detail in the embodiments of the display device can be found in the embodiment part of the display panel and will not be elaborated here.

[0132] The basic principles of the present application have been described above in conjunction with specific embodiments. However, it should be noted that the advantages, benefits, effects, etc. mentioned in the present application are only examples and not limitations, and it cannot be considered that these advantages, benefits, effects, etc. are essential for each embodiment of the present application. In addition, the above-disclosed specific details are only for the purpose of illustration and facilitating understanding, rather than limitations. The above details do not limit the present application to necessarily adopt the above specific details to implement.

[0133] The block diagrams of the devices, apparatuses, equipment, and systems involved in the present application are only illustrative examples and do not intend to require or imply that they must be connected, arranged, and configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, equipment, and systems can be connected, arranged, and configured in any manner. Words such as "including", "comprising", "having", etc. are open-ended words, meaning "including but not limited to", and can be used interchangeably with each other. The word "or" and "and" used here refer to the word "and / or" and can be used interchangeably with each other, unless the context clearly indicates otherwise. The word "such as" used here refers to the phrase "such as but not limited to" and can be used interchangeably with each other.

[0134] It should also be noted that in the devices, equipment, and methods of the present application, each component or each step can be decomposed and / or recombined. These decompositions and / or recombinations should be regarded as equivalent solutions of the present application.

[0135] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use the present application. Various modifications to these aspects are very obvious to those skilled in the art, and the general principles defined herein can be applied to other aspects without departing from the scope of the present application. Therefore, the present application is not intended to be limited to the aspects shown herein, but rather to the broadest scope consistent with the principles and novel features disclosed herein.

[0136] The foregoing description has been presented for purposes of illustration and description. Furthermore, this description is not intended to limit embodiments of the present application to the forms disclosed herein. Although several example aspects and embodiments have been discussed above, those skilled in the art will recognize some variations, modifications, alterations, additions, and sub-combinations thereof.

[0137] The above specific implementation manners do not constitute a limitation on the protection scope of the present invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An organic electroluminescent device, characterized in that, include: electron blocking layer; a light-emitting layer, located on one side of the electron blocking layer; as well as a hole blocking layer, located on a side of the light-emitting layer away from the electron blocking layer; The light-emitting layer includes a first sub-light-emitting layer in contact with the electron blocking layer and a second sub-light-emitting layer in contact with the hole blocking layer, and at most one of the first sub-light-emitting layer and the second sub-light-emitting layer includes a phosphorescent material.

2. The organic electroluminescent device according to claim 1, wherein The first sub-light emitting layer includes a host material, a fluorescent material and the phosphorescent material; Preferably, the second sub-light-emitting layer includes the host material; Preferably, the second sub-light-emitting layer includes the host material and the fluorescent material; Preferably, the thickness of the second sub-luminescence layer is greater than or equal to 1 nanometer and less than or equal to 5 nanometers.

3. The organic electroluminescent device according to claim 1, wherein The second sub-light emitting layer includes a host material, a fluorescent material and the phosphorescent material; Preferably, the first sub-light-emitting layer includes the host material; Preferably, the first sub-light-emitting layer includes the host material and the fluorescent material; Preferably, the thickness of the first sub-luminescence layer is greater than or equal to 1 nanometer and less than or equal to 5 nanometers.

4. The organic electroluminescent device according to claim 1, wherein The light-emitting layer further includes a third sub-light-emitting layer, the third sub-light-emitting layer is located between the first sub-light-emitting layer and the second sub-light-emitting layer, and the third sub-light-emitting layer includes a host material, a fluorescent material and the phosphorescent material; Preferably, one of the first light-emitting sub-layer and the second light-emitting sub-layer comprises the phosphorescent material; Preferably, the first sub-light-emitting layer and the second sub-light-emitting layer do not include the phosphorescent material; Preferably, the main body material includes a blue main body material; Preferably, the phosphorescent material includes a blue phosphorescent material; Preferably, the fluorescent material includes a blue fluorescent material; Preferably, the light-emitting layer includes a blue light-emitting layer; Preferably, the light-emitting layer is at least one of a green light-emitting layer, a red light-emitting layer and a yellow light-emitting layer.

5. The organic electroluminescent device according to claim 4, characterized in that, The first sub-light emitting layer includes the host material, and the second sub-light emitting layer includes the host material; Alternatively, the first sub-light emitting layer includes the host material, and the second sub-light emitting layer includes the host material and the fluorescent material; Or, the first sub-light emitting layer includes the host material, and the second sub-light emitting layer includes the host material, the fluorescent material and the phosphorescent material; Alternatively, the first sub-light-emitting layer includes the host material and the fluorescent material, and the second sub-light-emitting layer includes the host material; Or, the first sub-light emitting layer includes the host material and the fluorescent material, and the second sub-light emitting layer includes the host material and the fluorescent material; Or, the first sub-light emitting layer includes the host material, the fluorescent material and the phosphorescent material, and the second sub-light emitting layer includes the host material; Alternatively, the first sub-light emitting layer includes the host material, the fluorescent material and the phosphorescent material, and the second sub-light emitting layer includes the host material and the fluorescent material; Alternatively, the first sub-light emitting layer includes the host material and the fluorescent material, and the second sub-light emitting layer includes the host material, the fluorescent material and the phosphorescent material.

6. The organic electroluminescent device according to claim 4, characterized in that The main body material includes a first main body material and a second main body material with different materials; Preferably, the first sub-light-emitting layer includes the first main body material, and the second sub-light-emitting layer includes the second main body material; Preferably, the first sub-light-emitting layer includes the second main body material, and the second sub-light-emitting layer includes the first main body material; Preferably, the first main body material includes an electron-withdrawing group; Preferably, the second main body material includes an electron-donating group.

7. The organic electroluminescent device according to claim 1, characterized in that, It further includes an anode layer and a cathode layer. The anode layer is located on the side of the electron blocking layer away from the light-emitting layer, and the cathode layer is located on the side of the hole blocking layer away from the light-emitting layer; Preferably, it further includes a hole injection layer and / or a hole transport layer located between the anode layer and the electron blocking layer; Preferably, it further includes an electron transport layer and / or an electron injection layer located between the hole blocking layer and the cathode layer.

8. A method for preparing an organic electroluminescent device, characterized in that, It includes: An electron blocking layer, a light-emitting layer, and a hole blocking layer are sequentially prepared on one side of the anode layer. The light-emitting layer includes a first sub-light-emitting layer in contact with the electron blocking layer and a second sub-light-emitting layer in contact with the hole blocking layer. At most one of the first sub-light-emitting layer and the second sub-light-emitting layer includes a phosphorescent material; A cathode layer is prepared on the side of the hole blocking layer away from the anode layer.

9. The preparation method according to claim 8, wherein The step of sequentially preparing an electron blocking layer, a light-emitting layer, and a hole blocking layer on one side of the anode layer includes: An electron blocking layer is prepared on one side of the anode layer; The main body material is placed in a first evaporation source, the fluorescent material is placed in a second evaporation source, and the phosphorescent material is placed in a third evaporation source; The first sub-light-emitting layer and the second sub-light-emitting layer are prepared on the side of the electron blocking layer away from the anode layer through the first evaporation source, the second evaporation source, and the third evaporation source. Among them, at most one of the first sub-light-emitting layer and the second sub-light-emitting layer includes the phosphorescent material; A hole blocking layer is prepared on the side of the second sub-light-emitting layer away from the anode layer; Preferably, the step of evaporating through the first evaporation source, the second evaporation source, and the third evaporation source on the side of the electron blocking layer away from the anode layer to form the first sub-light-emitting layer and the second sub-light-emitting layer includes: Setting a first evaporation angle range of the first evaporation source, a second evaporation angle range of the second evaporation source, and a third evaporation angle range of the third evaporation source. Among them, the second evaporation angle range is less than or equal to the first evaporation angle range, and the third evaporation angle range is less than the first evaporation angle range; Based on the first evaporation angle range, the second evaporation angle, and the third evaporation angle range, evaporation is performed on the side of the electron blocking layer away from the anode layer to form the first sub-light-emitting layer and the second sub-light-emitting layer. Among them, at most one of the first sub-light-emitting layer and the second sub-light-emitting layer includes the phosphorescent material; Preferably, the step of evaporating through the first evaporation source, the second evaporation source, and the third evaporation source on the side of the electron blocking layer away from the anode layer to form the first sub-light-emitting layer and the second sub-light-emitting layer includes: Set the first evaporation time of the first evaporation source, the second evaporation time of the second evaporation source, and the third evaporation time of the third evaporation source, wherein the second evaporation time is less than or equal to the first evaporation time, and the third evaporation time is less than the first evaporation time; Based on the first evaporation time, the second evaporation time, and the third evaporation time, perform evaporation on the side of the electron blocking layer away from the anode layer to form the first sub-light emitting layer and the second sub-light emitting layer, wherein at most one of the first sub-light emitting layer and the second sub-light emitting layer includes the phosphorescent material.

10. A display panel, characterized in that: Comprising the organic electroluminescent device according to any one of claims 1-7, or comprising the organic electroluminescent device prepared by the preparation method according to claim 8 or 9.

Images