CN110854280A

CN110854280A - Light-emitting device, preparation method thereof and display device

Info

Publication number: CN110854280A
Application number: CN201911167133.7A
Authority: CN
Inventors: 胡春静
Original assignee: BOE Technology Group Co Ltd
Current assignee: BOE Technology Group Co Ltd
Priority date: 2019-11-25
Filing date: 2019-11-25
Publication date: 2020-02-28

Abstract

A light emitting device comprising: the anode layer, the hole injection layer, the hole transport layer, the light-emitting layer, the electron transport layer and the cathode layer are stacked in sequence; wherein the material of the electron transport layer comprises an n-doped organic material. The application also provides a preparation method of the light-emitting device and a display device.

Description

Light-emitting device, preparation method thereof and display device

Technical Field

The present disclosure relates to display technologies, and particularly to a light emitting device, a method for manufacturing the light emitting device, and a display device.

Background

An Organic Light-Emitting Diode (OLED) belongs to an electroluminescent device, has the characteristics of self luminescence, high luminous efficiency, low working voltage, lightness, thinness, flexibility, simple manufacturing process and the like, and is widely applied in the fields of display illumination and the like. The film deposition method of the OLED mainly comprises an evaporation process and a solution process, wherein the evaporation process is suitable for organic micromolecules, and has the advantages of uniform film formation, relatively mature technology, large equipment investment, low material utilization rate and low mask alignment precision of large-size products; the solution process comprises spin coating, ink-jet printing, nozzle coating and the like, is suitable for polymer materials and soluble small molecules, and has the characteristics of low equipment cost and outstanding advantages in large-scale and large-size production.

In the top-emitting OLED, in order to enable light emitted from the light-emitting layer to be emitted from the top of the OLED through the cathode, a metal layer with a small thickness is generally formed as the cathode by vapor deposition or evaporation, but the metal layer has a large resistance, and particularly for a large-sized OLED, a large voltage drop (IR-drop) is caused between the middle portion and the edge portion of the OLED, and the uniformity of the light-emitting luminance is poor. In view of the above problems, it is common to fabricate an auxiliary electrode on the array substrate, and the cathode layer is connected to the auxiliary electrode to reduce the voltage drop of the top cathode layer through the high conductivity of the auxiliary electrode. The above-described arrangement of the auxiliary electrodes requires the development of a full-print top-emitting OLED. However, such full-printed top-emitting OLEDs suffer from the following disadvantages: the selectable solution system materials are few; the device structure is too simple, the optical and electrical characteristics are difficult to balance, and the adjusting window is small; the film layer is difficult to print excessively thick, because the sub-pixels become smaller along with the improvement of the resolution of the display device, the printing ink overflow is easily caused by the excessively thick printing film layer, and the film forming uniformity is influenced.

Disclosure of Invention

The application provides a light-emitting device, a preparation method thereof and a display device, which can solve the problems of full-printing top-emitting OLEDs (organic light emitting diodes) required by arranging auxiliary electrodes in the related art.

In one aspect, the present application provides a light emitting device comprising: the anode layer, the hole injection layer, the hole transport layer, the light-emitting layer, the electron transport layer and the cathode layer are stacked in sequence; wherein the material of the electron transport layer comprises an n-doped organic material.

In another aspect, the present application provides a display apparatus including the light emitting device as described above.

In another aspect, the present application provides a method of manufacturing a light emitting device, including: sequentially forming an anode layer, a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer and a cathode layer which are stacked on a substrate; wherein the material of the electron transport layer comprises an n-doped organic material.

In the light emitting device provided by the application, the material of the electron transport layer comprises an n-doped organic material, so that the electron transport layer has higher conductivity and can be used as an auxiliary electrode of the cathode layer, the voltage drop of the cathode layer is reduced through the high conductivity of the electron transport layer, and the uniformity of the light emitting brightness of the light emitting device is improved; moreover, the electron transport layer can adjust the optical characteristics of the light emitting device and share the process difficulty brought by the thickness of the solution layer while not affecting the electrical characteristics of the light emitting device.

Additional features and advantages of the application will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of the application. Other advantages of the present application may be realized and attained by the instrumentalities and combinations particularly pointed out in the specification and the drawings.

Drawings

The accompanying drawings are included to provide an understanding of the present disclosure and are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and together with the examples serve to explain the principles of the disclosure and not to limit the disclosure. The shapes and sizes of the various elements in the drawings are not to scale and are merely intended to illustrate the invention.

Fig. 1 is a schematic structural diagram of a light-emitting device provided in a first embodiment of the present application;

FIG. 2 is a schematic view of a first embodiment of the present disclosure after forming an anode layer and a pixel defining layer;

FIG. 3 is a schematic view of a cathode layer formed according to a first embodiment of the present application;

FIG. 4 is a schematic diagram of the conductive characteristics of electron transport layers of different thicknesses according to the first embodiment of the present application;

fig. 5 is a schematic structural diagram of a light emitting device according to a second embodiment of the present application.

Description of reference numerals:

10-a substrate; 11-an anode layer; 12-a hole injection layer; 13-a hole transport layer; 14-a light-emitting layer; 15-electron transport layer; 16-an electron injection layer; 17-a cathode layer; 18-a pixel defining layer; k-open area.

Detailed Description

The present application describes embodiments, but the description is illustrative rather than limiting and it will be apparent to those of ordinary skill in the art that many more embodiments and implementations are possible within the scope of the embodiments described herein. Although many possible combinations of features are shown in the drawings and discussed in the detailed description, many other combinations of the disclosed features are possible. Any feature or element of any embodiment may be used in combination with or instead of any other feature or element in any other embodiment, unless expressly limited otherwise.

The present application includes and contemplates combinations of features and elements known to those of ordinary skill in the art. The embodiments, features and elements disclosed in this application may also be combined with any conventional features or elements to form a unique inventive concept as defined by the claims. Any feature or element of any embodiment may also be combined with features or elements from other inventive aspects to form yet another unique inventive aspect, as defined by the claims. Thus, it should be understood that any of the features shown and/or discussed in this application may be implemented alone or in any suitable combination. Accordingly, the embodiments are not limited except as by the appended claims and their equivalents. Furthermore, various modifications and changes may be made within the scope of the appended claims.

Further, in describing representative embodiments, the specification may have presented the method and/or process as a particular sequence of steps. However, to the extent that the method or process does not rely on the particular order of steps set forth herein, the method or process should not be limited to the particular sequence of steps described. Other orders of steps are possible as will be understood by those of ordinary skill in the art. Therefore, the particular order of the steps set forth in the specification should not be construed as limitations on the claims. Further, the claims directed to the method and/or process should not be limited to the performance of their steps in the order written, and one skilled in the art can readily appreciate that the sequences may be varied and still remain within the spirit and scope of the embodiments of the present application.

In order to solve the problems of a full-printing top-emitting OLED (organic light emitting diode) required by arranging an auxiliary electrode in the related art, the embodiment of the application provides a light emitting device, a preparation method thereof and a display device. The embodiment of the application provides a light-emitting device, includes: the organic light Emitting diode comprises an anode Layer, a Hole Injection Layer (HIL), a Hole Transport Layer (HTL), an Emitting Layer (EML), an Electron Transport Layer (ETL) and a cathode Layer which are sequentially stacked, wherein the material of the Electron transport Layer comprises an n-doped organic material.

In an exemplary embodiment, the organic material may include at least one of: aluminum quinolate (AlQ3), TPBI (1, 3, 5-tris (N-phenylbenzimidazol-2-yl) benzene). However, this is not limited in this application.

In an exemplary embodiment, the electron transport layer may have a thickness in a range of less than or equal to 1500 angstroms. For example, the electron transport layer can have a thickness of 200 angstroms, 400 angstroms, 800 angstroms, 1200 angstroms, or 1500 angstroms. This is not limited by the present application.

In an exemplary embodiment, the light emitting device may further include: an Electron Injection Layer (EIL) between the light emitting Layer and the electron transport Layer.

In an exemplary embodiment, the material of the electron injection layer satisfies the following condition: matching an energy level barrier between the light emitting layer and the electron transport layer; balancing the electron carriers between the light emitting layer and the electron transporting layer.

In an exemplary embodiment, the electron injection layer may have a thickness in a range of less than or equal to 1 nanometer (i.e., 10 angstroms). For example, the thickness of the electron injection layer may be 1 nm. However, this is not limited in this application.

The electron transport layer of the light-emitting device provided by the embodiment has good conductivity, and can be used as an auxiliary electrode of the cathode layer, so that the brightness uniformity of the light-emitting device can be improved; moreover, the electronic transmission layer can adjust the optical characteristics of the light-emitting device while not influencing the electrical characteristics of the light-emitting device, thereby balancing the electrical characteristics and the optical characteristics of the light-emitting device and sharing the process difficulty brought by the thickness of the solution layer; in addition, the electron transport layer is directly contacted with the cathode layer, and compared with a light-emitting device with an auxiliary electrode arranged on the array substrate, the preparation process of the light-emitting device can be simplified.

First embodiment

Fig. 1 is a schematic structural diagram of a light emitting device according to a first embodiment of the present application. As shown in fig. 1, the present embodiment provides a light emitting device including: an anode layer 11, a hole injection layer 12, a hole transport layer 13, a light emitting layer 14, an electron transport layer 15, and a cathode layer 17 are sequentially stacked.

Wherein the material of the electron transport layer 15 comprises an n-doped organic material. Illustratively, the organic material may include at least one of: AlQ3, TPBI.

The material of the hole injection layer 12 may be polyaniline or other material series; the material of the hole transport layer 13 may be polyaniline conductive polymer; the material of the light-emitting layer 14 may be a high molecular phosphorescent or fluorescent material.

The thickness of the hole injection layer 12 may be greater than or equal to 10 nanometers (nm) and less than or equal to 130nm, for example, 10 nm; the thickness of the hole transport layer 13 may range from less than or equal to 30nm, for example, may be 20 nm; the thickness of the light-emitting layer 14 may range from 50nm or more to 90nm or less, for example, 50 or 55 nm; the electron transport layer 15 may have a thickness in the range of 150nm or less (i.e., 1500 angstroms), for example, 20 nm. However, this is not limited in this application.

The operating principle of the above-described light emitting device is that holes are injected from the anode layer and transported at the HOMO levels (highest occupied molecular orbital) of the hole injection layer and the hole transport layer to finally reach the HOMO level of the light emitting layer, and electrons are injected from the cathode layer and transported at the LUMO level (lowest unoccupied molecular orbital) of the electron transport layer to finally reach the LUMO level of the light emitting layer. Under the action of external electricity, electrons positioned on the LUMO energy level of the luminescent layer are compounded with holes positioned on the HOMO energy level of the luminescent layer, and the luminescent material in the luminescent layer is excited to radiate photons outwards, so that the device can emit light.

The technical solution of this embodiment is further described below by the manufacturing process of the light emitting device of this embodiment. The "patterning process" in this embodiment includes processes such as depositing a film, coating a photoresist, exposing a mask, developing, etching, and stripping a photoresist, and is a well-established manufacturing process in the related art. The deposition may be performed by a known process such as sputtering, evaporation, chemical vapor deposition, etc., the coating may be performed by a known coating process, and the etching may be performed by a known method, which is not particularly limited herein.

The manufacturing process of the light emitting device of the present embodiment includes:

step one, forming an anode layer and a pixel defining layer on a substrate. Forming the anode layer and the pixel defining layer on the substrate includes: depositing a conductive film on a substrate 10, patterning the conductive film through a patterning process, and forming an anode layer 11 pattern on the substrate 10; a pixel defining film is deposited on the substrate 10 formed with the aforementioned pattern, exposed through a mask, and developed to form a pattern of a pixel defining layer 18, as shown in fig. 2.

The substrate 10 may be an array substrate. Before the anode layer and the pixel defining layer are formed, a pixel circuit layer and a flat layer provided with a via hole may be sequentially formed on the substrate, and the pixel circuit layer may include a pixel circuit corresponding to each sub-pixel region. The sub-pixel region refers to a region where a sub-pixel structure to be formed on the substrate is located, for example, a region where a red sub-pixel (i.e., a sub-pixel emitting red light) is located, a region where a green sub-pixel (i.e., a sub-pixel emitting green light) is located, or a region where a blue sub-pixel (i.e., a sub-pixel emitting blue light) is located.

The anode layer 11 includes an anode in each sub-pixel region, and the anode in each sub-pixel region may be connected to a pixel circuit corresponding to the sub-pixel region through a via hole in the sub-pixel region. The pixel defining layer 18 may be formed with a plurality of opening regions K arranged in an array, each of which exposes the anode electrode in one sub-pixel region. Wherein, the surface of the anode and the opening region K in the pixel defining layer 18 exposing the anode may form a groove, and each groove forms a sub-pixel structure.

The conductive film may be made of a metal material, such as silver (Ag), copper (Cu), aluminum (Al), molybdenum (Mo), or an alloy material of the above metals, such as aluminum neodymium alloy (AlNd), molybdenum niobium alloy (MoNb), or a multilayer metal, such as Mo/Cu/Mo, or a stack structure formed by a metal and a transparent conductive material, such as ITO/Ag/ITO. The pixel defining film may be a polyimide material mixed with fluorine. However, this is not limited in this application.

And step two, forming a hole injection layer. Forming the hole injection layer includes: on the substrate 10 formed with the aforementioned pattern, a hole injection layer 12 is formed on the anode exposed in the opening region K of the pixel defining layer 18 by a solution process (e.g., an inkjet printing method), as shown in fig. 3.

The material of the hole injection layer 12 may be polyaniline or other materials. In one example, the hole injection layer 12 may have a thickness of 10 nm.

And step three, forming a hole transport layer. Forming the hole transport layer includes: a hole transport layer 13 is formed on the hole injection layer 12 in the opening region K of the pixel defining layer 18 by a solution process (e.g., an inkjet printing method), as shown in fig. 3.

The material of the hole transport layer 13 may be polyaniline conductive polymer. In one example, the hole transport layer 13 may have a thickness of 20 nm.

And step four, forming a light emitting layer. The forming of the light emitting layer includes: a light-emitting layer 14 is formed on the hole transport layer 13 in the opening region K of the pixel defining layer 18 by a solution process (e.g., an inkjet printing method), as shown in fig. 3.

The material of the light emitting layer 14 may be a polymer phosphorescent or fluorescent material. In one example, the thickness of the light emitting layer 14 may be 50nm or 55 nm.

And step five, forming an electron transport layer. Forming the electron transport layer includes: an electron transport layer 15 is formed on the light emitting layer 14 in the opening region K of the pixel defining layer 18 by using an evaporation process (e.g., a vacuum evaporation process), as shown in fig. 3.

The material of the electron transport layer 15 may include an n-doped organic material, among others. In one example, the thickness of the electron transport layer 15 may be 20 nm. In the embodiment, the high-conductivity electron transport layer is prepared by adopting an evaporation process, and the thickness of the solution layer (light-emitting layer) can be shared, so that the thickness of the solution layer is reduced, the problem of ink overflow in the film printing process is solved, the film forming uniformity is improved, and an optical adjustment effect is achieved.

FIG. 4 is a schematic diagram of the conductive characteristics of electron transport layers with different thicknesses according to the first embodiment of the present application. The conductive properties of the electron transport layers are illustrated in FIG. 4 for thicknesses of 200 angstroms, 400 angstroms, 800 angstroms, 1200 angstroms, and 1500 angstroms, where the abscissa represents Voltage (Voltage) in volts (V) and the ordinate represents Current Density (Current Density) in mA/cm². As can be seen from fig. 4, the electron transport layers having thicknesses of 200 angstroms, 400 angstroms, 800 angstroms, 1200 angstroms, and 1500 angstroms have similar conductive characteristics, and thus, the optical characteristics of the light emitting device can be adjusted by changing the thickness of the electron transport layer without affecting the electrical characteristics of the light emitting device, thereby balancing the optical and electrical characteristics of the light emitting device.

And step six, forming a cathode layer. Forming the cathode layer includes: a cathode layer 17 is formed on the electron transport layer 15 and the pixel defining layer 18 by an evaporation process (e.g., a vacuum evaporation process), as shown in fig. 3.

Among them, since the light emitting device is a top emission device, the cathode layer 17 may be made of a transparent material. For example, the material of the cathode layer 17 may be magnesium (Mg), silver (Ag), aluminum (Al), or the like.

And a light emitting Layer (CPL) can be formed on the cathode Layer for improving the light emitting rate of the light emitting device. The preparation method of the light-emitting increasing layer is the same as that of the related art, and therefore, the description thereof is omitted.

The electron transport layer of the light-emitting device provided by the embodiment has higher conductivity and can be used as an auxiliary electrode, so that the voltage drop of the top cathode layer is reduced through the high conductivity of the electron transport layer, and the brightness uniformity of the light-emitting device is improved; moreover, the electronic transmission layer can adjust the optical characteristics of the light-emitting device while not influencing the electrical characteristics of the light-emitting device, thereby balancing the electrical and optical characteristics of the light-emitting device and sharing the process difficulty brought by the thickness of the solution layer; in addition, the electron transport layer is in direct contact with the top cathode layer, and compared with a light-emitting device with an auxiliary electrode arranged on the array substrate, the preparation process of the light-emitting device can be simplified.

In addition, the preparation process can be realized by utilizing the existing mature preparation equipment, the improvement on the existing process is small, and the preparation process can be well compatible with the existing preparation process, so that the process is simple to realize, easy to implement, high in production efficiency, easy to realize, low in production cost, high in yield and the like, and has a good application prospect.

Second embodiment

Fig. 5 is a schematic structural diagram of a light emitting device according to a second embodiment of the present application. As shown in fig. 5, the present embodiment provides a light emitting device including: an anode layer 11, a hole injection layer 12, a hole transport layer 13, a light emitting layer 14, an electron injection layer 16, an electron transport layer 15, and a cathode layer 17 are sequentially stacked on a substrate 10.

The main structure of the light emitting device of the present embodiment is substantially the same as that of the first embodiment, and is different from the first embodiment in that: an electron injection layer 16 is provided between the light-emitting layer 14 and the electron transport layer 15. Among them, the material of the electron injection layer 16 may satisfy the following condition: matching the energy level barrier between the light emitting layer 14 and the electron transport layer 15; balancing the electron carriers between the light-emitting layer 14 and the electron transport layer 15. For example, the material of the electron injection layer 16 may include at least one of: lithium fluoride (LiF), sodium fluoride (NaF), lithium hydroxyquinoline (LiQ), sodium hydroxyquinoline (NaQ). Wherein the thickness of the electron injection layer 16 is in the range of 1nm or less. In one example, the thickness of the electron injection layer 16 may be 1 nm.

The manufacturing process of the light emitting device of the present embodiment is substantially the same as that of the light emitting device of the first embodiment except that: the method also comprises the following steps between the fourth step and the fifth step: an electron injection layer is formed, wherein the electron injection layer is formed on the light emitting layer of the opening region of the pixel defining layer using an evaporation process (e.g., a vacuum evaporation process). In step five, an evaporation process (e.g., a vacuum evaporation process) is used to form an electron transport layer on the electron injection layer in the opening region of the pixel defining layer.

In one example, the display effect of the light emitting device of the present embodiment is illustrated in table 1, taking red light (R) and green light (G) as an example. Where voltage denotes voltage at real current density. In this example, the thickness of the hole injection layer may be 10nm, the thickness of the hole transport layer may be 20nm, the thickness of the light emitting layer may be 50nm, the thickness of the electron transport layer may be 20nm, and the thickness of the electron injection layer may be 1 nm.

	Luminous efficiency (unit cd/A)	Voltage (Unit V)	Chromaticity coordinates CIE (x, y)
				Red light	36.4	3.8	0.671，0.328
Green light	73.2	4.3	0.255，0.698

TABLE 1

As can be seen from table 1, the light emitting device provided in this embodiment does not need to separately dispose an auxiliary electrode on the array substrate, and can achieve a better display effect.

The electron injection layer arranged between the light-emitting layer and the electron transport layer in the embodiment can play a role in enhancing the microcavity of the top-emitting device; in addition, when the light emitting layer and the electron transport layer are directly adjacent, the n doping in the electron transport layer may generate a quenching phenomenon with the light emitting layer, and the present embodiment can separate the light emitting layer and the electron transport layer by providing the electron injection layer, increase the electron injection, and move the recombination region of carriers to the center of the light emitting layer at the boundary of the light emitting layer and the electron transport layer, thereby preventing the quenching phenomenon.

The present embodiment also achieves the technical effects of the first embodiment, and by providing the electron transport layer with higher conductivity and the electron injection layer for balancing the electron carriers, the luminance uniformity of the light emitting device can be improved, and the electron transport layer can adjust the optical characteristics of the light emitting device and share the process difficulty caused by the thickness of the solution layer without affecting the electrical characteristics of the light emitting device; in addition, compared with a light-emitting device with an auxiliary electrode arranged on the array substrate, the preparation process of the light-emitting device can be simplified.

Third embodiment

Based on the technical idea of the embodiment of the application, the embodiment of the application further provides a preparation method of the light-emitting device. The preparation method of the light-emitting device provided by the embodiment comprises the following steps: sequentially forming an anode layer, a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer and a cathode layer which are stacked on a substrate; wherein the material of the electron transport layer comprises an n-doped organic material.

In an exemplary embodiment, sequentially forming an anode layer, a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, and a cathode layer stacked on a substrate may include: forming an anode layer on a substrate; forming a hole injection layer, a hole transport layer and a light-emitting layer on the anode layer in sequence by adopting a solution process; and sequentially forming an electron transport layer and a cathode layer on the light-emitting layer by adopting an evaporation process.

In an exemplary embodiment, the electron transport layer may have a thickness in a range of less than or equal to 1500 angstroms.

In an exemplary embodiment, the preparation method of the embodiment may further include: and forming an electron injection layer between the light-emitting layer and the electron transport layer by using an evaporation process.

In an exemplary embodiment, the material of the electron injection layer may satisfy the following condition: matching an energy level barrier between the light emitting layer and the electron transport layer; balancing electron carriers between the light emitting layer and the electron transport layer.

The manufacturing process of the light emitting device has been described in detail in the previous embodiments, and is not described herein again.

Fourth embodiment

Based on the technical idea of the embodiments of the present application, embodiments of the present application also provide a display apparatus including the light emitting device of the foregoing embodiments. Wherein, the display device can be: any product or component with a display function, such as a mobile phone, a tablet computer, a television, a display, a notebook computer, a digital photo frame, a navigator and the like.

In the description of the embodiments of the present application, it should be understood that the terms "middle", "upper", "lower", "front", "rear", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed in a particular orientation, and be operated, and therefore, should not be construed as limiting the present application.

In the description of the embodiments of the present application, it should be noted that the terms "mounted," "connected," and "connected" are to be construed broadly and may be, for example, fixedly connected, detachably connected, or integrally connected unless explicitly stated or limited otherwise; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

Although the embodiments disclosed in the present application are described above, the descriptions are only for the convenience of understanding the present application, and are not intended to limit the present application. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the disclosure as defined by the appended claims.

Claims

1. A light emitting device, comprising:

the anode layer, the hole injection layer, the hole transport layer, the light-emitting layer, the electron transport layer and the cathode layer are stacked in sequence; wherein the material of the electron transport layer comprises an n-doped organic material.

2. The light-emitting device according to claim 1, wherein the organic material comprises at least one of: aluminum quinolate, TPBI.

3. The light-emitting device according to claim 1, wherein the electron transport layer has a thickness in a range of 1500 angstroms or less.

4. The light-emitting device according to claim 1, further comprising: an electron injection layer between the light emitting layer and the electron transport layer.

5. The light-emitting device according to claim 4, wherein a material of the electron injection layer satisfies the following condition: matching an energy level barrier between the light emitting layer and the electron transport layer; balancing electron carriers between the light emitting layer and the electron transport layer.

6. The light-emitting device according to claim 4, wherein the electron injection layer has a thickness in a range of 1nm or less.

7. A display device characterized by comprising the light-emitting device according to any one of claims 1 to 6.

8. A method of making a light emitting device, comprising:

sequentially forming an anode layer, a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer and a cathode layer which are stacked on a substrate;

wherein the material of the electron transport layer comprises an n-doped organic material.

9. The method according to claim 8, wherein the sequentially forming a stack of the anode layer, the hole injection layer, the hole transport layer, the light emitting layer, the electron transport layer, and the cathode layer on the substrate comprises:

forming an anode layer on a substrate;

forming a hole injection layer, a hole transport layer and a light-emitting layer on the anode layer in sequence by adopting a solution process;

and sequentially forming an electron transport layer and a cathode layer on the light-emitting layer by adopting an evaporation process.

10. The method of claim 9, wherein the electron transport layer has a thickness in a range of less than or equal to 1500 angstroms.

11. The production method according to any one of claims 8 to 10, characterized by further comprising: and forming an electron injection layer between the light-emitting layer and the electron transport layer by using an evaporation process.

12. The production method according to claim 11, wherein a material of the electron injection layer satisfies the following condition: matching an energy level barrier between the light emitting layer and the electron transport layer; balancing electron carriers between the light emitting layer and the electron transport layer.