CN115020603A

CN115020603A - Electroluminescent device, display device and manufacturing method of electroluminescent device

Info

Publication number: CN115020603A
Application number: CN202210677766.8A
Authority: CN
Inventors: 郝艳军; 文官印; 李彦松; 杜小波; 吴淞全; 左鹏飞; 屈财玉
Original assignee: BOE Technology Group Co Ltd
Current assignee: BOE Technology Group Co Ltd
Priority date: 2022-06-15
Filing date: 2022-06-15
Publication date: 2022-09-06

Abstract

The invention discloses an electroluminescent device, a display device and a method for manufacturing the electroluminescent device, wherein the electroluminescent device comprises: an anode layer; a first light-emitting layer, arranged on one side of the anode layer; and a second light-emitting layer, arranged on On the side of the first light-emitting layer away from the anode layer, both the first light-emitting layer and the second light-emitting layer include at least a blue light-emitting unit; wherein, the blue light-emitting unit of at least one of the first light-emitting layer and the second light-emitting layer The electron mobility of the host material is not less than 1×10-7cm2/(V·s); the charge generation layer is arranged between the first light-emitting layer and the second light-emitting layer; and the cathode layer is arranged on the second light-emitting layer away from the anode side of the layer. The invention can reduce the cross-voltage of the blue light-emitting unit in the electroluminescent device and reduce the overall power consumption of the device.

Description

Electroluminescent device, display device and manufacturing method of electroluminescent device

Technical Field

The invention relates to the technical field of display, in particular to an electroluminescent device, a display device and a manufacturing method of the electroluminescent device.

Background

The OLED (Organic Light-Emitting Diode) has attracted more attention due to its characteristics of active Light emission, high brightness, high resolution, wide viewing angle, fast response speed, low power consumption, flexibility, and the like. With the progress of the OLED display technology and the application of the OLED display panel to products in different fields, the performance requirements of customers on the OLED products are higher and higher; for example, the display quality, power consumption, energy saving, and service life of the OLED display panel are included. To meet the application in the middle-sized products such as vehicles, notebook computers, tablet computers, etc., Tandem OLEDs (OLED) are widely developed. Currently, when the Tandem OLED is applied to products such as notebook computers and tablet computers, energy is required to be saved as much as possible so as to realize longer battery endurance; however, the voltage of the conventional Tandem OLED device is still high during operation, which results in high power consumption.

Disclosure of Invention

In view of the above problems, the present invention provides an electroluminescent device, a display device, and a method for manufacturing the electroluminescent device, which can reduce the voltage across the blue light emitting unit in the electroluminescent device and reduce the overall power consumption of the device.

In a first aspect, the present application provides the following technical solutions through an embodiment:

an electroluminescent device comprising:

an anode layer; a first light emitting layer disposed on one side of the anode layer; a second light-emitting layer disposed on a side of the first light-emitting layer away from the anode layer, the first light-emitting layer and the second light-emitting layer each including at least a blue light-emitting unit; wherein electron migration of a host material of a blue light emitting unit of at least one of the first light emitting layer and the second light emitting layerShift rate not less than 1 x 10 ^-7 cm ² V · s; a charge generation layer disposed between the first light emitting layer and the second light emitting layer; and the cathode layer is arranged on one side of the second light-emitting layer far away from the anode layer.

Optionally, the electron mobility of the host material of the blue light emitting unit in the first light emitting layer is not less than 1 × 10 ^-7 cm ² /(V·s)。

Optionally, the electron mobility of the blue light emitting unit in the first light emitting layer is greater than the electron mobility of the blue light emitting unit in the second light emitting layer, and the hole mobility of the blue light emitting unit in the first light emitting layer is smaller than the hole mobility of the blue light emitting unit in the second light emitting layer.

Optionally, the molecular structure of the host material of the blue light-emitting unit of the first light-emitting layer contains an electron-withdrawing group.

Optionally, the electron withdrawing group comprises any one or more of:

nitrogen-containing heterocycle, oxygen atom, acylamino and acyloxy.

Optionally, the host material of the blue light emitting unit of the first light emitting layer includes any one or more of:

1-4-bis- [4- (N, N-diphenyl) amino ] styrylbenzene;

2- (4-biphenyl) -5-phenyl oxadiazole;

2, 9-dimethyl-4, 7-diphenyl-1, 10-phenanthroline;

4, 7-diphenyl-1, 10-phenanthroline;

2-hydroxy-3-methyl-2-cyclopenten-1-one.

Optionally, the thickness of the blue light-emitting unit in the first light-emitting layer is 10nm to 30 nm.

Optionally, the molecular structure of the host material of the blue light emitting unit of the second light emitting layer contains an electron donating group.

Optionally, the electron-donating group comprises any one or more of:

fluorenes, carbazoles, aromatic amines.

Optionally, the method further includes: a hole transport unit layer and an electron transport unit layer; the hole transport unit layer is disposed between the anode layer and the first light emitting layer; the electron transport unit layer is disposed between the cathode layer and the second light emitting layer.

In a second aspect, based on the same inventive concept, the present application provides the following technical solutions through an embodiment:

a display apparatus comprising an electroluminescent device as claimed in any one of the preceding first aspects.

In a third aspect, based on the same inventive concept, the present application provides the following technical solutions through an embodiment:

a method of manufacturing an electroluminescent device comprising:

providing a driving back plate; sequentially forming an anode layer, a first light-emitting layer, a charge generation layer, a second light-emitting layer and a cathode layer on one side of the driving backboard; wherein electron mobility of a host material of a blue light emitting unit of at least one of the first light emitting layer and the second light emitting layer is not less than 1 × 10 ^-7 cm ² /(V·s)。

In an embodiment of the present invention, an electroluminescent device, a display apparatus, and a method for manufacturing an electroluminescent device include: an anode layer; a first light emitting layer disposed at one side of the anode layer; the second light-emitting layer is arranged on one side, far away from the anode layer, of the first light-emitting layer, and the first light-emitting layer and the second light-emitting layer at least comprise blue light-emitting units; wherein the electron mobility of the host material of the blue light-emitting unit of at least one of the first light-emitting layer and the second light-emitting layer is not less than 1 × 10-7cm2/(V · s); a charge generation layer disposed between the first light emitting layer and the second light emitting layer; and the cathode layer is arranged on one side of the second light-emitting layer far away from the anode layer. Wherein at least one of electron mobility of the blue light emitting unit through the first light emitting layer and electron mobility of the blue light emitting unit through the second light emitting layer is controlled to be not less than 1 × 10 ^-7 cm ² And V · s, thereby effectively reducing the voltage across the blue light-emitting unit when the electroluminescent device is in operation and reducing the power consumption of the device.

The foregoing description is only an overview of the technical solutions of the present invention, and the embodiments of the present invention are described below in order to make the technical means of the present invention more clearly understood and to make the above and other objects, features, and advantages of the present invention more clearly understandable.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the description below are some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on the drawings without creative efforts.

Fig. 1 is a schematic structural diagram of an electroluminescent device provided in an embodiment of the present invention;

FIGS. 2-8 are schematic diagrams of molecular structures of different materials for implementing BH1 in an embodiment of the present invention;

fig. 9 is a flow chart of a method of manufacturing an electroluminescent device in an embodiment of the invention.

Detailed Description

Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. It should be understood that the description is illustrative only and is not intended to limit the scope of the present disclosure. Moreover, in the following description, descriptions of well-known structures and techniques are omitted so as to not unnecessarily obscure the concepts of the present disclosure.

Various structural schematics according to embodiments of the present disclosure are shown in the figures. The figures are not drawn to scale, wherein certain details are exaggerated and possibly omitted for clarity of presentation. The shapes of various regions, layers, and relative sizes and positional relationships therebetween shown in the drawings are merely exemplary, and deviations may occur in practice due to manufacturing tolerances or technical limitations, and a person skilled in the art may additionally design regions/layers having different shapes, sizes, relative positions, as actually required.

In the context of the present disclosure, when a layer/element is referred to as being "on" another layer/element, it can be directly on the other layer/element or intervening layers/elements may be present. In addition, if a layer/element is "on" another layer/element in one orientation, then that layer/element may be "under" the other layer/element when the orientation is reversed.

An electroluminescent device provided in embodiments of the present invention may be a tandem OLED device including a first light-emitting layer and a second light-emitting layer connected by a charge-generating layer. Further, the OLED device may be a top-emitting OLED device or a bottom-emitting OLED device, without limitation. At present, the voltage and power consumption of the device during operation are significantly affected by the blue light-emitting material, so that the OLED device in the application is improved for the blue light-emitting unit in the first light-emitting layer and/or the second light-emitting layer, thereby significantly reducing the overall voltage and power consumption of the device. In the OLED device of the present embodiment, the electron mobility of the blue light-emitting unit of the first light-emitting layer and the electron mobility of the blue light-emitting unit of the second light-emitting layer are controlled to be not less than 1 × 10 ^-7 cm ² And V · s, thereby effectively reducing the voltage across the OLED device during operation and reducing the power consumption of the device. The concept of the present invention is explained below by specific examples.

Referring to fig. 1, an electroluminescent device provided in this embodiment includes: an Anode layer (Anode)11, a hole transport unit layer 12, a first Emission layer (EML) 13, a Charge Generation Layer (CGL) 14, a second Emission layer 15, an electron transport unit layer 16, and a Cathode layer (Cathode) 17.

The anode layer 11 may be made of anode metal or other anode material. Further, the anode layer 11 may be disposed on one side of the driving backplate.

A hole transport unit layer 12 arranged on one side of the anode layer 11 far away from the driving backboard; specifically, the Hole transport unit Layer 12 may include a Hole Injection Layer (HIL) and a Hole Transport Layer (HTL); the hole injection layer is disposed between the hole transport layer and the anode layer 11.

And a first light emitting layer 13 disposed on a side of the hole transport unit layer 12 away from the anode layer 11. In some implementations, a first buffer layer (Prime material) may also be disposed between the first light emitting layer 13 and the hole transport unit layer 12; that is, the first light emitting layer 13 is disposed on the first buffer layer, i.e., on a side of the first buffer layer away from the anode layer 11. The first light-emitting layer 13 is divided into a plurality of light-emitting units, specifically including a blue light-emitting unit, a green light-emitting unit, and a red light-emitting unit; wherein, each light emitting unit can be isolated by the barrier structure 131. For convenience of description, the blue light-emitting unit, the green light-emitting unit, and the red light-emitting unit in the first light-emitting layer 13 are hereinafter referred to as a first blue light-emitting unit BEML1, a first green light-emitting unit GEML1, and a first red light-emitting unit REML1, respectively.

The Host material (Host material) of the first blue light emitting cell BEML1 may employ an electron mobility of not less than 1 × 10 ^- ⁷ cm ² And the organic small molecular material containing the pi conjugated structure of the material is marked as a main material BH 1. Especially materials containing electron withdrawing groups. For example, electron withdrawing groups include any one or more of the following: nitrogen-containing heterocycles, oxygen atoms, amide groups, acyloxy groups, and the like. As another example, the host material BH1 may be any one or more of the following:

1-4-bis- [4- (N, N-diphenyl) amino ] styrylbenzene (DSA-Ph1) (or 4,4' - [1, 4-phenylenedi- (1E) -2, 1-ethenediyl ] bis [ N, N-diphenylaniline ]), and the molecular structure is shown in FIG. 2.

2- (4-biphenyl) -5-phenyl oxadiazole (PBD) and the molecular structure is shown in figure 3.

2, 9-dimethyl-4, 7-diphenyl-1, 10-phenanthroline (BCP), the molecular structure is shown in figure 4.

4, 7-diphenyl-1, 10-phenanthroline (Bphen), and the molecular structure is shown in figure 5.

2-hydroxy-3-methyl-2-cyclopenten-1-one (mcP), the molecular structure is shown in FIG. 6.

In addition, the material can also be a CZTT material, and the molecular structure is shown in figure 7; and the material can also be CBP material, and the molecular structure is shown in figure 8.

In addition, the host material of the first blue light emitting cell BEML1 may also employ a hole mobility of not less than 1 × 10 ^- ⁹ cm ² And the organic small molecular material containing the pi conjugated structure of the material is marked as a main material BH 2. In particular, materials containing electron donating groups can be used. For example, electron donating groups include any one or more of the following: fluorenes, carbazoles, aromatic amines, and the like.

In any case, the host material of the first blue light-emitting cell BEML1 may be a fluorescent Dopant, a phosphorescent Dopant, or the like, and the Dopant material (Dopant material) is not limited. In this embodiment, the proportion of the doping material may be controlled to 0.2% to 5% to achieve the balance of the power consumption and the lifetime of the first blue light emitting cell BEML 1; the doping material is denoted as doping material BD.

A charge generation layer 14 provided on a side of the first light-emitting layer 13 away from the anode layer 11; it is to be understood that the charge generation layer 14 is positioned between the first light emitting layer 13 and the second light emitting layer 15 for connecting the first light emitting layer 13 and the second light emitting layer 15. In some implementations, the charge generation layer 14 can include an N-doped charge generation layer 14 and a P-doped charge generation layer 14, i.e., an N-doped charge generation layer and a P-doped charge generation layer in sequence from the direction of the anode layer 11 to the cathode layer 17.

And a second light emitting layer 15 provided on the side of the charge generation layer 14 away from the anode layer 11. The structure of the second light-emitting layer 15 may be the same as that of the first light-emitting layer 13; specifically, in some implementations, a second buffer layer may also be disposed between the second light emitting layer 15 and the charge generation layer 14. That is, the second light emitting layer 15 is disposed on the second buffer layer, i.e., on a side of the second buffer layer away from the anode layer 11. The second light emitting layer 15 may also be divided into a plurality of light emitting units, specifically including a blue light emitting unit, a green light emitting unit, and a red light emitting unit; wherein, each light emitting unit can be isolated by the barrier structure 151. For convenience of description, the blue light-emitting unit, the green light-emitting unit, and the red light-emitting unit in the second light-emitting layer 15 will be hereinafter referred to as a second blue light-emitting unit BEML2, a second green light-emitting unit GEML2, and a second red light-emitting unit REML2, respectively.

Similarly, the material selection and doping ratio of the second blue light-emitting unit BEML2 can refer to the implementation manner of the first blue light-emitting unit BEML1 without limitation. The first blue light-emitting unit BEML1 and the second blue light-emitting unit BEML2 may be implemented in the same manner or in different manners; however, it should be ensured that the electron mobility of at least one of the host materials is not less than 1 × 10 ^-7 cm ² V · s to ensure effective reduction of voltage across and power consumption of the entire OLED device.

Further, in this embodiment, the thickness of the blue light emitting unit in the first light emitting layer 13 and the second light emitting layer 15 may be controlled to be 10nm to 30 nm; in particular, the thickness of the blue light-emitting cell of the host material BH1 can be controlled to 10nm to 30nm to achieve a good balance between power consumption and lifetime of the blue light-emitting cell.

And an electron transport unit layer 16 disposed on a side of the second light emitting layer 15 away from the anode layer 11. The Electron Transport unit Layer 16 may include a Hole Block Layer (HBL), an Electron Transport Layer (ETL), and an Electron Injection Layer (EIL). The hole transport layer is disposed on the side of the second light emitting layer 15 away from the anode layer 11, the electron transport layer is disposed on the side of the second light emitting layer 15 away from the anode layer 11, and the electron injection layer is disposed on the side of the second light emitting layer 15 away from the anode layer 11.

And a cathode layer 17 disposed on a side of the electron transport unit layer 16 remote from the anode layer 11. The transparent properties of the cathode layer 17 and the anode layer 11 may be determined based on whether the OLED device is a top-emitting or bottom-emitting device, without limitation.

Further, the first blue light emitting unit BEML1 and the second blue light emitting unit BEML2 of the OLED device in the present embodiment may be embodied as follows:

the first method comprises the following steps: the material composition of the first blue light-emitting unit BEML1 and the second blue light-emitting unit BEML2 are the same.

The host materials of the first blue light-emitting cell BEML1 and the second blue light-emitting cell BEML2 are both host materials BH 1. Correspondingly, the proportion of the doping material BD is controlled to be 0.2% -5%. Thus, both the first blue light-emitting unit BEML1 and the second blue light-emitting unit BEML2 are electron type Host materials (E-type Host), and a blue light-emitting unit of a low voltage system can be formed. That is, the host material BH1 has faster electron mobility, and the resulting OLED device has sufficiently small voltage swing, thereby achieving effective reduction in power consumption.

And the second method comprises the following steps: the first blue light-emitting unit BEML1 and the second blue light-emitting unit BEML2 are different in material; also, the electron mobility of the second blue light emitting cell BEML2 is greater.

It is understood that the host material of the first blue light-emitting cell BEML1 may employ the host material BH 2; the host material of the second blue light-emitting cell BEML may be the host material BH 1. The proportions of the respective dopant materials BD of the first and second blue light-emitting cells BEML1 and BEML2 may be controlled to be 0.2% to 5%. Thus, the Host material BH2 is a hole-type Host material (H-type Host), and can form a long-life blue light-emitting unit. The host material BH1 is an electronic host material, and can form a blue light-emitting unit of a low-voltage system. When two materials are used simultaneously, the service life of the blue light-emitting unit can be prevented from being excessively reduced while the cross-voltage is reduced.

However, through analysis, it is found that the above two methods can better optimize the overall power consumption of the OLED device, but can significantly affect the lifetime of the blue light-emitting unit when emitting blue light (blue light lifetime) and the lifetime of the blue light-emitting unit when emitting white light (white light lifetime). The second embodiment is still less desirable than the first embodiment, although the lifetime of the blue light emitting unit can be improved to some extent. Further, the present embodiment also provides the following third implementation manner. Specifically, the electron mobility of the blue light-emitting unit in the first light-emitting layer 13 is greater than the electron mobility of the blue light-emitting unit in the second light-emitting layer 15, and the hole mobility of the blue light-emitting unit in the first light-emitting layer 13 is smaller than the hole mobility of the blue light-emitting unit in the second light-emitting layer 15. That is, this makes it possible to make the second blue light-emitting cell BEML2 closer to the cathode layer 17 have higher hole mobility, with reduced influence of electron bombardment; meanwhile, the first blue light emitting cell BEML1 has higher electron mobility, can realize lower cross voltage, reduces power consumption, and realizes better balance between power consumption and service life. The following is a third example:

and the third is that: the first blue light-emitting unit BEML1 and the second blue light-emitting unit BEML2 are different in material; also, the electron mobility of the first blue light-emitting cell BEML1 is greater.

That is, in this implementation, the second blue light-emitting cell BEML2 closer to the cathode layer 17 is formed of the host material BH2 and the dopant material BD, which is a hole-type host material, and thus a long-life system blue light-emitting cell can be formed. The method avoids the problem that when the main body material BH1 is adopted, the influence of electron bombardment is larger when the main body material BH1 is closer to the cathode layer 17, and the main body material BH1 is easy to degrade. When the body material BH1 is applied to be closer to the anode layer 11, the influence of electron bombardment is obviously reduced, the service life of the first blue light-emitting unit BEML1 is effectively prolonged, and the effects of reducing the overall voltage and power consumption of the device are realized; a good balance between power consumption and lifetime is achieved.

Further, after the above three examples are tested, the power consumption optimization effect and the lifetime of the blue light emitting unit can be seen in table 1 below.

Table 1 comparison table of effect of different materials of first blue light emitting unit and second blue light emitting unit

As can be seen from table 1, with the first implementation manner in this embodiment, power consumption optimization can be achieved by more than 6% compared with a conventional structure, and a blue light lifetime can also be ensured to a certain extent. When the second implementation manner in this embodiment is adopted, although the power consumption optimization effect is reduced to some extent, the blue light lifetime is significantly improved, and the balance between the power consumption optimization effect and the lifetime of the blue light emitting unit is realized. Further, when the third implementation manner is adopted, the power consumption optimization effect can be basically equal to that in the second implementation manner, but the blue light service life and the white light service life are obviously prolonged, a better balance between the power consumption optimization effect and the blue light emitting unit service life is realized, and the method can be more favorably applied to a middle-sized display panel, such as 7-18 inches.

In summary, in the electroluminescent device provided in this embodiment, the overall power consumption of the OLED device is effectively reduced by designing the materials of the blue light emitting units in the first light emitting layer and the second light emitting layer, and the service life of the blue light emitting unit can be kept better.

Based on the same inventive concept, in yet another embodiment of the present invention, there is also provided a display apparatus including the electroluminescent device described in any one of the preceding embodiments. The display device can be a display panel applied to products such as mobile phones, notebook computers, tablet computers, portable displays, vehicle-mounted displays and the like, and can also be a finished product of the products without limitation. The display panel in this embodiment adopts the electroluminescent device in any one of the foregoing embodiments, and the specific implementation and technical effects thereof can be illustrated in the foregoing embodiments, and the details of the structure of the display panel, which are not described, can be implemented by referring to the existing technical means, without limitation.

Referring to fig. 9, based on the same inventive concept, in another embodiment of the present invention, a method for manufacturing an electroluminescent device is further provided, which can be used to manufacture the electroluminescent device of any one of the foregoing embodiments. In some implementations, a method of manufacturing the electroluminescent device includes the steps of:

firstly, providing a driving back plate; the driving back plate can be used for driving an organic light-emitting structure which is manufactured subsequently, and can be manufactured by referring to the conventional common technical means, which is not repeated. Further, an anode layer, a first light-emitting layer, a charge generation layer, and a second light-emitting layer are sequentially formed on the driving back plateAnd a cathode layer; wherein electron mobility of a host material of a blue light emitting unit of at least one of the first light emitting layer and the second light emitting layer is not less than 1 × 10 ^-7 cm ² V · s. A hole transport unit layer may be further formed after the anode layer is formed and before the first light emitting layer is formed; after the second light emitting layer is formed and before the cathode layer is formed, an electron transport unit layer may be further formed.

For example:

it can be understood that, when the hole transport unit layer is manufactured on the driving backplane, the Hole Injection Layer (HIL) and the Hole Transport Layer (HTL) of the hole transport unit may be evaporated using an Open Mask; next, the buffer layer of the corresponding first blue light-emitting cell BEML1 in the first light-emitting layer and the first blue light-emitting cell BEML1 were evaporated using a FMM (Fine Metal Mask) corresponding to the blue light-emitting cell. The first blue light-emitting unit BEML1 can be a material of a low-voltage system and is formed by doping a main material BH1 and a doping material BD, wherein the proportion of the doping material can be controlled to be 0.2-5%, the molecular structure of the main material BH1 is an organic small molecule containing a pi conjugated structure, and materials containing electron-withdrawing groups, such as nitrogen-containing heterocycles, oxygen atoms, acylamino, acyloxy and the like, can be adopted. The main body material BH1 is an electron type main body material, and has faster electron mobility and electron mobility mue>1×10 ^-7 cm ² V · s, the device power consumption can be effectively reduced. Further, the thickness of the first blue light-emitting unit BEML1 controlled to be evaporated is 10nm to 30 nm.

Next, as in the case of depositing the first blue light-emitting unit BEML1, the buffer layer of the first green light-emitting unit GEML1 and the first green light-emitting unit GEML1 in the first light-emitting layer are deposited by using the FMM corresponding to the green light-emitting unit. And evaporating the buffer layer of the first red light-emitting unit REML1 and the first red light-emitting unit REML1 in the first light-emitting layer by adopting FMM corresponding to the red light-emitting unit.

Further, a Charge Generation Layer (CGL) was formed on the first light-emitting layer in this order by using Open Mask vapor deposition. Specifically, an N-type doped charge generation layer (nCGL) and a P-type doped charge generation layer (pCGL) were sequentially prepared.

Still further, FMM corresponding to the blue light emitting cell on the charge generation layer evaporates the buffer layer of the second blue light emitting cell BEML2 and the second blue light emitting cell BEML2 in the second light emitting layer. The second blue light-emitting unit BEML2 is a long-life blue light-emitting material, and is formed by doping a host material BH2 and a doping material BD, and the doping proportion of the doping material can be controlled to be 0.2% -5%. The molecular structure of the main material BH2 is an organic small molecule containing a pi conjugated structure, and materials containing electron donating groups such as fluorenes, carbazoles, arylamines and the like can be adopted. The main body material BH2 is a hole type main body material, the hole mobility is faster, and the hole mobility is muh>1×10 ^-9 cm ² /(V·s)。

Next, as in the case of depositing the second blue light emitting cell BEML2, the buffer layer of the second green light emitting cell GEML2 and the second green light emitting cell GEML2 in the second light emitting layer are deposited by using the FMM corresponding to the green light emitting cell. And evaporating the buffer layer of the second red light-emitting unit REML2 and the second red light-emitting unit REML2 in the second light-emitting layer by adopting FMM corresponding to the red light-emitting unit.

Further, an Open Mask evaporation is sequentially used for preparing a charge generation unit on the second light-emitting layer; specifically, a Hole Blocking Layer (HBL), an Electron Transport Layer (ETL) and an Electron Injection Layer (EIL) are sequentially evaporated. Next, a cathode Layer and a Capping Layer (CPL) were evaporated.

In the manufacturing process, the buffer layers corresponding to the first blue light-emitting unit BEML1 and the second blue light-emitting unit BEML2 can be made of the same material; the first green light-emitting unit GEML1 and the second green light-emitting unit GEML2 may be both the same material; the buffer layers corresponding to the first green light-emitting unit GEML1 and the second green light-emitting unit GEML2 may be made of the same material; the first red light-emitting unit REML1 and the second red light-emitting unit REML2 may be both the same material; the buffer layers corresponding to the first red light emitting cell REML1 and the second red light emitting cell REML2 may be all of the same material.

After the evaporation process is completed, the packaging process and the subsequent module process can be performed according to a conventional TFE (Thin Film Encapsulation) packaging process.

It should be noted that, in the manufacturing method of the electroluminescent device provided in this embodiment, the structure formed in each step may refer to the foregoing structure embodiment, and the beneficial effects produced by the structure in the foregoing embodiment related to the substrate frame sealing structure are already described, and specifically refer to the foregoing embodiment related to the substrate frame sealing structure, which is not repeated in this embodiment. The specific process implementation of each structure when being manufactured can adopt the existing process technology, and the embodiment is not limited.

In the above description, the technical details of patterning, etching, and the like of each layer are not described in detail. It will be appreciated by those skilled in the art that layers, regions, etc. of the desired shape may be formed by various technical means. In addition, in order to form the same structure, those skilled in the art can also design a method which is not exactly the same as the method described above. Further, although the embodiments are described separately above, this does not mean that the measures in the respective embodiments cannot be used advantageously in combination.

While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the invention.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.

Claims

1. An electroluminescent device, characterized in that, comprising:

anode layer;

a first light-emitting layer, disposed on one side of the anode layer;

The second light-emitting layer is disposed on the side of the first light-emitting layer away from the anode layer, and both the first light-emitting layer and the second light-emitting layer contain at least blue light-emitting units; wherein, the first light-emitting layer The electron mobility of the host material of the blue light-emitting unit of at least one of the layer and the second light-emitting layer is not less than 1×10 ^-7 cm ² /(V·s);

a charge generation layer disposed between the first light-emitting layer and the second light-emitting layer; and

The cathode layer is disposed on the side of the second light-emitting layer away from the anode layer.

2 . The electroluminescent device according to claim 1 , wherein the electron mobility of the host material of the blue light-emitting unit in the first light-emitting layer is not less than 1×10 ⁻⁷ cm ² /(V· s).

3 . The electroluminescent device according to claim 2 , wherein the electron mobility of the blue light-emitting unit in the first light-emitting layer is greater than that of the blue light-emitting unit in the second light-emitting layer. 4 . The hole mobility of the blue light-emitting unit in the first light-emitting layer is smaller than the hole mobility of the blue light-emitting unit in the second light-emitting layer.

4 . The electroluminescent device according to claim 1 , wherein the molecular structure of the host material of the blue light-emitting unit of the first light-emitting layer contains an electron withdrawing group. 5 .

5. The electroluminescent device of claim 4, wherein the electron withdrawing group comprises any one or more of the following:

Nitrogen-containing heterocycle, oxygen atom, amide group, acyloxy group.

6. The electroluminescent device according to claim 4, wherein the host material of the blue light-emitting unit of the first light-emitting layer comprises any one or more of the following:

1-4-bis-[4-(N,N-diphenyl)amino]styrylbenzene;

2-(4-biphenyl)-5-phenyloxadiazole;

2,9-Dimethyl-4,7-diphenyl-1,10-phenanthroline;

4,7-diphenyl-1,10-phenanthroline;

2-Hydroxy-3-methyl-2-cyclopenten-1-one.

7 . The electroluminescent device according to claim 1 , wherein the thickness of the blue light-emitting unit in the first light-emitting layer is 10 nm˜30 nm. 8 .

8 . The electroluminescent device according to claim 1 , wherein the molecular structure of the host material of the blue light-emitting unit of the second light-emitting layer contains an electron-donating group. 9 .

9. The electroluminescent device of claim 8, wherein the electron donating group comprises any one or more of the following:

Fluorenes, carbazoles, aromatic amines.

10. The electroluminescent device of claim 1, further comprising: a hole transport unit layer and an electron transport unit layer; the hole transport unit layer is disposed on the anode layer and the first between the light-emitting layers; the electron transport unit layer is disposed between the cathode layer and the second light-emitting layer.

11. A display device, characterized by comprising the electroluminescent device according to any one of claims 1-10.

12. A method for manufacturing an electroluminescent device, comprising:

Provide driver backplane;

An anode layer, a first light-emitting layer, a charge generation layer, a second light-emitting layer and a cathode layer are formed in sequence on one side of the driving backplane; wherein, at least one of the first light-emitting layer and the second light-emitting layer is The electron mobility of the host material of the blue light-emitting unit is not less than 1×10 ⁻⁷ cm ² /(V·s).