Light-emitting device and manufacturing method thereof

Abstract

The invention relates to a light-emitting device and a manufacturing method thereof. The light-emitting device comprises a first electrode layer, a first light-emitting layer, a buffer layer, a connecting layer, a second light-emitting layer and a second electrode layer which are sequentially stacked, wherein the connecting layer is arranged on the side, away from the first light-emitting layer, of the buffer layer and comprises a P-type charge generation layer and an N-type charge generation layer, the N-type charge generation layer is located between the P-type charge generation layer and the buffer layer, and the N-type charge generation layer comprises a first N-type electron transport material; the buffer layer comprises at least one sub-buffer layer, and the sub-buffer layer comprises at least one of a hole blocking material, an electron transport material and a second N-type electron transport material. According to the invention, the structure of the Tandem OLED is simplified, the process is simplified, the production cost can be effectively reduced, and the performance of the existing Tandem OLED is maintained or further improved.

Description

Technical Field

[0001] This application relates to the field of display technologies, and particularly to a light-emitting device and a method for manufacturing the same. Background Art

[0002] A tandem organic light-emitting diode (Tandem OLED) light-emitting device is a highly efficient light-emitting device formed by connecting two or more OLED light-emitting structures in series through a connection layer. During the manufacturing process of a Tandem OLED, its functional film layers are usually formed by evaporation. Since a Tandem OLED has a relatively large number of film layers, the number of evaporation chambers occupied is also relatively large, resulting in a relatively high process cost. Summary of the Invention

[0003] Embodiments of this application provide a light-emitting device and a method for manufacturing the same. This application simplifies the structure and process of a tandem light-emitting device (Tandem OLED), and can effectively reduce the production cost.

[0004] This application provides a light-emitting device, which includes:

[0005] A first electrode layer;

[0006] A first light-emitting layer disposed above the first electrode layer;

[0007] A buffer layer disposed on a side of the first light-emitting layer away from the first electrode layer;

[0008] A connection layer disposed on a side of the buffer layer away from the first light-emitting layer. The connection layer includes a P-type charge generation layer and an N-type charge generation layer. The N-type charge generation layer is located between the P-type charge generation layer and the buffer layer, and the N-type charge generation layer includes a first N-type electron transport material;

[0009] A second light-emitting layer disposed on a side of the connection layer away from the buffer layer; and

[0010] A second electrode layer disposed on a side of the second light-emitting layer away from the connection layer;

[0011] Wherein, the buffer layer includes at least one sub-buffer layer, and the sub-buffer layer includes at least one of a hole blocking material, an electron transport material, and a second N-type electron transport material. The buffer layer and the N-type charge generation layer are formed in the same evaporation chamber.

[0012] In some embodiments, the buffer layer includes a first sub-buffer layer, and the first sub-buffer layer includes the hole blocking material;

[0013] The lowest unoccupied molecular orbital energy level of the first N-type electron transport material is greater than the lowest unoccupied molecular orbital energy level of the hole blocking material.

[0014] In some embodiments, the buffer layer includes a second sub-buffer layer, and the second sub-buffer layer includes the second N-type electron transport material;

[0015] The first light-emitting layer includes a first organic light-emitting material;

[0016] The highest occupied molecular orbital energy level of the first N-type electron transport material and / or the second N-type electron transport material is greater than the highest occupied molecular orbital energy level of the first organic light-emitting material.

[0017] In some embodiments, the buffer layer includes a first sub-buffer layer and a second sub-buffer layer. The second sub-buffer layer is disposed between the first sub-buffer layer and the N-type charge generation layer. The first sub-buffer layer includes the hole blocking material, the second sub-buffer layer includes the second N-type electron transport material, and the second N-type electron transport material is the same as the first N-type electron transport material;

[0018] The lowest unoccupied molecular orbital energy level of the second N-type electron transport material is greater than the lowest unoccupied molecular orbital energy level of the hole blocking material.

[0019] In some embodiments, the buffer layer includes a third sub-buffer layer, and the third sub-buffer layer includes the electron transport material;

[0020] The first light-emitting layer includes a first organic light-emitting material;

[0021] The highest occupied molecular orbital energy level of the first N-type electron transport material and / or the electron transport material is greater than the highest occupied molecular orbital energy level of the first organic light-emitting material.

[0022] In some embodiments, the N-type charge generation layer further includes a first doped metal;

[0023] The buffer layer includes a third sub-buffer layer, and the third sub-buffer layer includes the electron transport material and a second doped metal, and the second doped metal has the same material as the first doped metal.

[0024] In some embodiments, the N-type charge generation layer further includes a first doped metal;

[0025] The buffer layer includes a fourth sub-buffer layer, and the fourth sub-buffer layer includes the second N-type electron transport material and a third doped metal, and the third doped metal has the same material as the first doped metal;

[0026] The doping concentration of the third doped metal in the fourth sub-buffer layer is greater than the doping concentration of the first doped metal in the N-type charge generation layer.

[0027] In some embodiments, the buffer layer further includes a second sub-buffer layer disposed between the fourth sub-buffer layer and the first light-emitting layer, and the second sub-buffer layer includes the second N-type electron transport material.

[0028] The present application also provides a method for manufacturing a light-emitting device, the method for manufacturing the light-emitting device including:

[0029] Forming a first electrode layer;

[0030] Forming a first light-emitting layer above the first electrode layer;

[0031] Forming a buffer layer and an N-type charge generation layer in sequence on a side of the first light-emitting layer away from the first electrode layer, and the buffer layer and the N-type charge generation layer are formed in the same evaporation chamber, wherein the N-type charge generation layer includes a first N-type electron transport material, the buffer layer includes at least one sub-buffer layer, and the sub-buffer layer includes at least one of a hole blocking material, an electron transport material, and a second N-type electron transport material;

[0032] Forming a P-type charge generation layer on a side of the N-type charge generation layer away from the buffer layer, wherein the P-type charge generation layer and the N-type charge generation layer constitute a connection layer;

[0033] Forming a second light-emitting layer on a side of the connection layer away from the buffer layer; and

[0034] Forming a second electrode layer on a side of the second light-emitting layer away from the connection layer.

[0035] In some embodiments, the N-type charge generation layer further includes a first doped metal;

[0036] The evaporation chamber includes a first evaporation source, a second evaporation source, and a third evaporation source. The first evaporation source is configured to evaporate one of the hole blocking material, the electron transport material, and the second N-type electron transport material, the second evaporation source is configured to evaporate the first N-type electron transport material, and the third evaporation source is configured to evaporate the first doped metal.

[0037] The present application provides a light-emitting device and a method for manufacturing the light-emitting device. The light-emitting device of the present application uses a buffer layer to replace the hole blocking layer and the electron transport layer in the existing Tandem OLED device structure, so as to simplify the Tandem OLED structure, and enable the buffer layer and the adjacent N-type charge generation layer to complete the film evaporation in the same evaporation chamber, that is, the buffer layer and the N-type charge generation layer are formed by single-chamber evaporation. Compared with the structure in which the existing hole blocking layer, electron transport layer, and N-type charge generation layer need to complete the film evaporation through multiple evaporation chambers, the present application reduces the number of occupied evaporation chambers, simplifies the process, and can effectively reduce costs. At the same time, the buffer layer of the present application may include at least one sub-buffer layer, and the sub-buffer layer includes at least one of a hole blocking material, an electron transport material, and a second N-type electron transport material. By adjusting the number of film layers of the buffer layer and the combination of the sub-buffer layer materials, the requirements of different device structures for the buffer layer function are met, so as to maintain or further improve the performance of the existing Tandem OLED device. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and those skilled in the art can obtain other drawings according to these drawings without creative efforts.

[0039] In order to more completely understand the present application and its beneficial effects, the following description will be made in conjunction with the drawings, where the same reference numerals represent the same parts in the following description.

[0040] Figure 1 is a schematic structural diagram of a light-emitting device provided by the related art;

[0041] Figure 2 is a schematic evaporation diagram of the first hole blocking layer, the first electron transport layer, and the N-type charge generation layer of a light-emitting device provided by the related art;

[0042] Figure 3 is a schematic structural diagram of one of the light-emitting devices provided by the embodiments of the present application;

[0043] Figure 4 is a schematic partial structural diagram of one of the light-emitting devices provided by the embodiments of the present application;

[0044] Figure 5 is a schematic partial structural diagram of one of the light-emitting devices provided by the embodiments of the present application;

[0045] Figure 6 is a schematic partial structural diagram of one of the light-emitting devices provided by the embodiments of the present application;

[0046] Figure 7 It is a schematic partial structure diagram of one of the light-emitting devices provided by the embodiments of the present application;

[0047] Figure 8 It is a schematic partial structure diagram of one of the light-emitting devices provided by the embodiments of the present application;

[0048] Figure 9 It is a schematic partial structure diagram of one of the light-emitting devices provided by the embodiments of the present application;

[0049] Figure 10 It is a J-V curve diagram of the embodiments and comparative examples of the present application;

[0050] Figure 11 It is a BI-J curve diagram of the embodiments and comparative examples of the present application;

[0051] Figure 12 It is an L-T curve diagram of the embodiments and comparative examples of the present application;

[0052] Figure 13 It is a vapor deposition schematic diagram of a buffer layer and an N-type charge generation layer of a light-emitting device provided by the embodiments of the present application.

[0053] Explanation of reference numerals:

[0054] 100, Light-emitting device; 101, Driving substrate; 110, First electrode layer; 120, First light-emitting layer; 121, First main light-emitting layer; 1211, Red first sub-main light-emitting layer; 1212, Green first sub-main light-emitting layer; 1213, Blue first sub-main light-emitting layer; 122, First auxiliary light-emitting layer; 1221, Red first sub-auxiliary light-emitting layer; 1222, Green first sub-auxiliary light-emitting layer; 1223, Blue first sub-auxiliary light-emitting layer; 130, Connection layer; 131, N-type charge generation layer; 132, P-type charge generation layer; 140, Second light-emitting layer; 141, Second main light-emitting layer; 1411, Red second sub-main light-emitting layer; 1412, Green second sub-main light-emitting layer; 1413, Blue second sub-main light-emitting layer; 142, Second auxiliary light-emitting layer; 1421, Red second sub-auxiliary light-emitting layer; 1422, Green second sub-auxiliary light-emitting layer; 1423, Blue second sub-auxiliary light-emitting layer; 150, Second electrode layer; 160, Encapsulation layer; 200, Buffer layer; 201, First sub-buffer layer; 202, Second sub-buffer layer; 203, Third sub-buffer layer; 204, Fourth sub-buffer layer; 301, Hole injection layer; 302, First hole transport layer; 303, First hole blocking layer; 304, First electron transport layer; 305, Second hole transport layer; 306, Second hole blocking layer; 307, Second electron transport layer; 308, Electron injection layer; 309, Optical coupling layer. Detailed implementation manners

[0055] 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 skilled in the art without creative efforts belong to the protection scope of the present application.

[0056] Please refer to Figure 1 , Figure 1 FIG. 130 is a schematic structural diagram of a light-emitting device provided for the related art. The light-emitting device includes a first electrode layer 110, a hole injection layer 301, a first hole transport layer 302, a first light-emitting layer 120, a first hole blocking layer 303, a first electron transport layer 304, an N-type charge generation layer 131, a P-type charge generation layer 132, a second hole transport layer 305, a second light-emitting layer 140, a second hole blocking layer 306, a second electron transport layer 307, an electron injection layer 308, and a second electrode layer 150, which are sequentially stacked. For example, when using an evaporation method with one cavity and three sources (i.e., 3 evaporation sources are provided in one evaporation chamber), at least two evaporation chambers are required for the first hole blocking layer 303, the first electron transport layer 304, and the N-type charge generation layer 131. Please refer to Figure 2 ,Figure 2 It is a vapor deposition schematic diagram of the first hole blocking layer, the first electron transport layer, and the N-type charge generation layer of a light-emitting device provided by the related art. Among them, in the vapor deposition chamber 1, there are a vapor deposition source S11, a vapor deposition source S12, and a vapor deposition source S13. The material of the vapor deposition source S11 is a hole blocking material (HB), which is used to vapor deposit and form the first hole blocking layer 303 (HBL1). The material of the vapor deposition source S12 is a doped metal, such as LiQ. The material of the vapor deposition source S13 is an electron transport material (ET). The vapor deposition sources S12 and S13 together vapor deposit and form the first electron transport layer 304 (ETL1); in the vapor deposition chamber 2, there are a vapor deposition source S21, a vapor deposition source S22, and a vapor deposition source S23. The material of the vapor deposition source S21 is an N-type electron transport material (NET). The material of the vapor deposition source S12 is a doped metal, such as Yb. The material of the vapor deposition source S13 is an N-type electron transport material (NET). The vapor deposition sources S21, S22, and S23 together vapor deposit and form the N-type charge generation layer 131 (NCGL). Therefore, in this light-emitting device structure, the first hole blocking layer 303, the first electron transport layer 304, and the N-type charge generation layer 131 need to occupy multiple vapor deposition chambers, and the process cost is relatively high.

[0057] To solve the above problems, the present application provides a light-emitting device 100. Please refer to Figure 3 , Figure 3 FIG. is a schematic structural diagram of a light-emitting device 100 provided by an embodiment of the present application. The light-emitting device 100 includes a first electrode layer 110, a first light-emitting layer 120, a buffer layer 200, a connection layer 130, a second light-emitting layer 140, and a second electrode layer 150. The first light-emitting layer 120 is disposed above the first electrode layer 110; the buffer layer 200 is disposed on a side of the first light-emitting layer 120 away from the first electrode layer 110; the connection layer 130 is disposed on a side of the buffer layer 200 away from the first light-emitting layer 120. The connection layer 130 includes a P-type charge generation layer 132 and an N-type charge generation layer 131. The N-type charge generation layer 131 is located between the P-type charge generation layer 132 and the buffer layer 200. The N-type charge generation layer 131 includes a first N-type electron transport material; the second light-emitting layer 140 is disposed on a side of the connection layer 130 away from the buffer layer 200; the second electrode layer 150 is disposed on a side of the second light-emitting layer 140 away from the connection layer 130; wherein, the buffer layer 200 includes at least one sub-buffer layer, and the sub-buffer layer includes at least one of a hole blocking material, an electron transport material, and a second N-type electron transport material. The buffer layer 200 and the N-type charge generation layer 131 are formed in the same vapor deposition chamber.

[0058] Among them, the light-emitting device 100 further includes a driving substrate 101 and a packaging layer 160. The driving substrate 101 is located on the side of the first electrode layer 110 away from the first light-emitting layer 120. The driving substrate 101 includes a substrate and a thin-film transistor array disposed on the substrate, and is used to drive the light-emitting device 100 to emit light. The packaging layer 160 is located on the side of the second electrode layer 150 away from the second light-emitting layer 140. The packaging layer 160 may be a thin-film encapsulation (TFT) structure, including one or more inorganic or organic thin films, and is used to protect the light-emitting device and block the erosion of water and oxygen.

[0059] The first electrode layer 110 may be an anode, and the second electrode layer 150 may be a cathode. Under the action of the driving voltage provided by the driving substrate 101, the anode is used to provide holes, and the cathode is used to provide electrons. The holes and electrons move towards the light-emitting layer, meet and recombine in the light-emitting layer to emit photons, so as to realize the light emission of the light-emitting device 100.

[0060] In this application, the light-emitting device 100 is a series-connected OLED light-emitting device 100, which at least includes a first light-emitting layer 120 and a second light-emitting layer 140. The first light-emitting layer 120 and the second light-emitting layer 140 are connected by a connection layer 130. Of course, the light-emitting device 100 may also include more than two light-emitting layers. Adjacent light-emitting layers are connected in series through the connection layer 130. When the light-emitting device 100 includes more than two light-emitting layers, the adjacent light-emitting layers may have the same or similar structure as that between the first light-emitting layer 120 and the second light-emitting layer 140 above.

[0061] Among them, the first light-emitting layer 120 includes a first host light-emitting layer 121, and the first host light-emitting layer 121 includes a first organic light-emitting material. The second light-emitting layer 140 includes a second host light-emitting layer 141, and the second host light-emitting layer 141 includes a second organic light-emitting material.

[0062] The connection layer 130, that is, the charge generation layer (Charge Generation Layer, CGL), includes a P-type charge generation layer 132 (PCGL) and an N-type charge generation layer 131 (NCGL) which are stacked. In the case of applying an electric field, due to the difference in work function between different materials in the CGL, a charge transfer phenomenon will occur, thereby generating electron-hole pairs. For example, hole carriers will be generated in the PCGL, and electron carriers will be generated in the NCGL. The CGL transports the generated electrons and holes to adjacent light-emitting layers or other functional layers respectively to realize the series operation of multiple light-emitting layers. In this application, the P-type charge generation layer 132 includes a P-type hole transport material. Further, it may also include a P-type doped metal. The N-type charge generation layer 131 includes a first N-type electron transport material. Further, it may also include a first doped metal, such as active metals like Yb, Mg, Ag, Li, etc.

[0063] In the present application, a buffer layer 200 is further included between the first light-emitting layer 120 and the N-type charge generation layer 131. The buffer layer 200 includes one or more sub-buffer layers. For example, the buffer layer 200 may include one sub-buffer layer, or two stacked sub-buffer layers, or three stacked sub-buffer layers. The sub-buffer layer may include at least one of a hole blocking material, an electron transport material, and a second N-type electron transport material to achieve different functions of different sub-buffer layers. For example, when the sub-buffer layer includes a hole blocking material, the sub-buffer layer has the function of blocking holes; when the sub-buffer layer includes an electron transport material, the sub-buffer layer has the function of transporting electrons; when the sub-buffer layer includes a second N-type electron transport material, the sub-buffer layer has functions such as transporting electrons and reducing the energy level barrier. Specifically, the number of sub-buffer layers included in the buffer layer 200 and the materials of each sub-buffer layer can be designed according to the structure and functional requirements of the light-emitting device 100, and are not limited herein.

[0064] In the present application, the hole blocking material is a material having the function of blocking holes, such as at least one of TPBI (1,3,5-tris(1-phenyl-1H-benzoimidazol-2-yl)benzene), BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline), BDTSO (2,5-bis(2',5'-dimethyl-4-triphenylsilyl-phenyl)-(1,3,4)oxadiazole), Alq 3 (aluminum tris(2-(2-hydroxyphenyl)benzoxazole)), n-pt1 (n-type polythiophene derivative), etc., but not limited thereto. The electron transport material is a material having the function of transporting electrons, such as at least one of Liq (lithium 8-hydroxyquinolineolate), PBD (2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole), TAZ (3-(4-biphenylyl)-4-phenyl-5-tert-butylphenyl-1,2,4-triazole), BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline), BAlq (bis(2-methyl-8-hydroxyquinolinato)-4-(phenylphenolato)aluminum), etc., but not limited thereto. The first N-type electron transport material and the second N-type electron transport material are materials having the function of transporting electrons that can be used as the N-type charge generation layer, such as N-type semiconductor materials, organic materials having electron transport properties, etc., such as ZnO, TiO 2 , pyridine derivatives, pyrimidine derivatives, triazine derivatives, imidazole derivatives, oxazole derivatives, and phenanthroline derivatives, etc., but not limited thereto. The second N-type electron transport material and the first N-type electron transport material may be the same or different.

[0065] In the present application, the second N-type electron transport material may have a relatively fast mobility to improve the electron transport efficiency of the buffer layer 200. The mobility range of the second N-type electron transport material is 10-6 ~10 -3 cm 2 / (V·S)。

[0066] In the present application, the second N-type electron transport material may have a relatively high HOMO energy level to enhance the ability of the buffer layer 200 to block holes and improve the electron transport efficiency. The HOMO energy level range of the second N-type electron transport material is -5.0 eV to -7.0 eV.

[0067] In some embodiments, please refer to Figure 4 , the buffer layer 200 includes a first sub-buffer layer 201, and the first sub-buffer layer 201 includes a hole blocking material, so that the first sub-buffer layer 201 has the function of blocking the diffusion of holes from the first light-emitting layer 120 to the N-type charge generation layer 131, so that the holes are as much as possible restricted within the first light-emitting layer 120 to increase the probability of recombination of holes and electrons in the first light-emitting layer 120, thereby improving the light-emitting efficiency. At the same time, it is possible to avoid holes entering the N-type charge generation layer 131 and accumulating, which may affect the first N-type electron transport material of the N-type charge generation layer 131, and further affect the performance of the N-type charge generation layer 131 and the lifetime of the light-emitting device 100.

[0068] Furthermore, the lowest unoccupied molecular orbital (LUMO) energy level of the first N-type electron transport material may be greater than the LUMO energy level of the hole blocking material. Using a material with a relatively high LUMO energy level for the first N-type electron transport material can promote electron transport and improve the electron migration efficiency, which is beneficial to improving the efficiency of the light-emitting device 100. At the same time, the LUMO energy level of the first N-type electron transport material being greater than the LUMO energy level of the hole blocking material can further block the diffusion of holes and improve the lifetime of the light-emitting device 100, etc.

[0069] In some embodiments, please refer to Figure 5, the buffer layer 200 includes a second sub-buffer layer 202. The second sub-buffer layer 202 includes a second N-type electron transport material and has the function of transporting electrons and reducing the energy level barrier. Further, the highest occupied molecular orbital (HOMO) energy level of the first N-type electron transport material and / or the second N-type electron transport material is greater than the HOMO energy level of the first organic light-emitting material, so as to enhance the ability of the second sub-buffer layer 202 and / or the N-type charge generation layer 131 to block holes. For example, when the HOMO energy level of the first N-type electron transport material is greater than the HOMO energy level of the first organic light-emitting material, the ability of the N-type charge generation layer 131 to block holes can be further enhanced; when the HOMO energy level of the second N-type electron transport material is greater than the HOMO energy level of the first organic light-emitting material, the second sub-buffer layer 202 also has the function of blocking holes.

[0070] In some embodiments, please refer to Figure 6 , the buffer layer 200 includes a first sub-buffer layer 201 and a second sub-buffer layer 202. The second sub-buffer layer 202 is disposed between the first sub-buffer layer 201 and the N-type charge generation layer 131. The first sub-buffer layer 201 includes a hole blocking material and has the function of blocking holes. The second sub-buffer layer 202 includes a second N-type electron transport material and has the function of transporting electrons. Further, the lowest unoccupied molecular orbital (LUMO) energy level of the second N-type electron transport material is greater than the LUMO energy level of the hole blocking material, and the second sub-buffer layer 202 also has the function of reducing the energy level barrier. When using a vapor deposition method with one cavity and three sources, the second N-type electron transport material is the same as the first N-type electron transport material.

[0071] In some embodiments, please refer to Figure 7 , the buffer layer 200 includes a third sub-buffer layer 203. The third sub-buffer layer 203 includes an electron transport material and has the function of transporting electrons. Further, the HOMO energy level of the first N-type electron transport material and / or the electron transport material is greater than the HOMO energy level of the first organic light-emitting material, so as to enhance the ability of the third sub-buffer layer 203 and / or the N-type charge generation layer 131 to block holes. For example, when the HOMO energy level of the first N-type electron transport material is greater than the HOMO energy level of the first organic light-emitting material, the ability of the N-type charge generation layer 131 to block holes can be further enhanced; when the HOMO energy level of the electron transport material is greater than the HOMO energy level of the first organic light-emitting material, the third sub-buffer layer 203 also has the function of blocking holes.

[0072] In some embodiments, please refer to Figure 7, the buffer layer 200 includes a third sub-buffer layer 203. The third sub-buffer layer 203 includes an electron transport material and a second doped metal. The second doped metal is used to improve the electron mobility of the third sub-buffer layer 203. When using a one-chamber three-source evaporation method, the second doped metal has the same material as the first doped metal. Among them, both the second doped metal and the first doped metal have a certain coupling ability with the electron transport material and the first N-type electron transport material. In this embodiment, the second doped metal and the first doped metal can be metal Li, but are not limited thereto. When the second doped metal is Li, on the one hand, it can improve the electron mobility of the third sub-buffer layer 203, and on the other hand, it can realize co-evaporation of the third sub-buffer layer 203 and the N-type charge generation layer 131 in the same chamber, so as to reduce the number of occupied evaporation chambers, reduce costs, and the electron transport material of the third sub-buffer layer 203 no longer needs to use LiQ.

[0073] In some embodiments, please refer to Figure 8 , the buffer layer 200 includes a fourth sub-buffer layer 204. The fourth sub-buffer layer 204 includes a second N-type electron transport material and a third doped metal. The fourth sub-buffer layer 204 has the function of transporting electrons and a relatively high electron mobility; when using a one-chamber three-source evaporation method, the third doped metal has the same material as the first doped metal.

[0074] Furthermore, the doping concentration of the third doped metal in the fourth sub-buffer layer 204 is greater than the doping concentration of the first doped metal in the N-type charge generation layer 131, which can prevent the first doped metal in the N-type charge generation layer 131 from penetrating into the P-type charge generation layer 132 and affecting the performance of the N-type charge generation layer 131 and the P-type charge generation layer 132.

[0075] In this embodiment, the first N-type electron transport material and the second N-type electron transport material can be the same or different.

[0076] In some embodiments, please refer to Figure 9 , the buffer layer 200 includes a second sub-buffer layer 202 and a fourth sub-buffer layer 204. The second sub-buffer layer 202 is disposed between the fourth sub-buffer layer and the first light-emitting layer 120. The second sub-buffer layer 202 includes a second N-type electron transport material. The second sub-buffer layer 202 has the functions of transporting electrons and reducing the energy level barrier. The fourth sub-buffer layer 204 includes a second N-type electron transport material and a third doped metal. The fourth sub-buffer layer 204 has the function of transporting electrons and a relatively high electron mobility; when using a one-chamber three-source evaporation method, the third doped metal has the same material as the first doped metal.

[0077] Further, the doping concentration of the third doped metal in the fourth sub-buffer layer 204 is greater than the doping concentration of the first doped metal in the N-type charge generation layer 131, which can prevent the first doped metal in the N-type charge generation layer 131 from penetrating into the P-type charge generation layer 132 and affecting the performance of the N-type charge generation layer 131 and the P-type charge generation layer 132.

[0078] In this embodiment, the first N-type electron transport material and the second N-type electron transport material may be the same or different.

[0079] In the above embodiment, the doping concentration range of the first doped metal in the N-type charge generation layer 131 is 0.1% to 20%; the doping concentration range of the third doped metal in the fourth sub-buffer layer 204 is 0.1% to 20%; the doping concentration range of the second doped metal in the third sub-buffer layer 203 is 0.1% to 90%.

[0080] In the above embodiment, the film layer combination of the buffer layer 200 and the N-type charge generation layer 131 can replace the film layer combination of the first hole blocking layer 303, the first electron transport layer 304 and the N-type charge generation layer 131 in the related art, simplifying the structure of the light-emitting device 100, and at the same time being able to maintain or further improve the performance of the existing Tandem OLED device. At the same time, the buffer layer 200 and the N-type charge generation layer 131 are formed in the same evaporation chamber, which can reduce the number of evaporation chambers occupied in the manufacturing process of the light-emitting device 100, simplify the process and reduce the cost.

[0081] Please refer to Figures 10 - 12 , and the light-emitting device 100 of the present application will be further described below through specific embodiments and comparative examples.

[0082] Embodiment: A buffer layer 200 and an N-type charge generation layer 131 are included between the first light-emitting layer 120 and the P-type charge generation layer 132. The buffer layer 200 includes a first sub-buffer layer 201 and a second sub-buffer layer 202. The first sub-buffer layer 201 includes a hole blocking material, and the second sub-buffer layer 202 includes a second N-type electron transport material. The N-type charge generation layer 131 includes a first N-type electron transport material and a first doped metal. Please refer to Figures 10 - 12 , the first sub-buffer layer 201 is represented by HBL, the second sub-buffer layer 202 is represented by NETx, the N-type charge generation layer 131 is represented by NCGL, the first N-type electron transport material is represented by NETx, and the first doped metal is represented by Yb. The structure of this embodiment is represented by HBL + NETx + NCGL (NETx: Yb).

[0083] Comparative Example: A first hole blocking layer 303, a first electron transport layer 304 and an N-type charge generation layer 131 are included between the first light-emitting layer 120 and the P-type charge generation layer 132. Please refer toFigures 10 - 12 , the first hole blocking layer 303 is denoted by HBL, the first electron transport layer 304 is denoted by ETL1, the N-type charge generation layer 131 is denoted by NCGL, and the comparative structure is denoted by HBL + ETL1 + NCGL.

[0084] Other structures in the light-emitting devices represented by the above embodiments and comparative examples are the same. Please refer to Figure 3 and Figure 1 .

[0085] The current density-voltage tests were respectively carried out on the light-emitting devices of the embodiments and the comparative examples. The test results are shown in the J-V curve diagram in Figure 10 . It can be seen from the J-V curve diagram that at the same voltage, the current density of the embodiments of the present application is lower than that of the comparative example, and the performance is better.

[0086] The blue light OLED device efficiency-current density tests were respectively carried out on the light-emitting devices of the embodiments and the comparative examples. The test results are shown in the BI-J curve diagram in Figure 11 . It can be seen from the BI-J curve diagram that the device efficiencies of the embodiments and the comparative examples of the present application are comparable, and the efficiency performance of the light-emitting devices of the present application has not deteriorated significantly.

[0087] The light emission decay-time tests were respectively carried out on the light-emitting devices of the embodiments and the comparative examples. The test results are shown in the L-T curve diagram in Figure 12 . It can be seen from the L-T curve diagram that the device lifetimes (solid lines) of the embodiments and the comparative examples of the present application are comparable, and the drift voltages (dashed lines) are lower. The lifetimes of the light-emitting devices of the present application have not deteriorated and the stability is better.

[0088] It can be illustrated by Figures 10 - 12 that while ensuring that the efficiency and lifetime performance of the light-emitting devices of the embodiments of the present application are comparable to those of the comparative examples, excellent performance with low voltage and high stability can be obtained.

[0089] In some embodiments, the light-emitting device 100 may further include at least one of a hole injection layer 301, a first hole transport layer 302, a second hole transport layer 305, a second hole blocking layer 306, a second electron transport layer 307, an electron injection layer 308, and a light coupling layer 309 (CPL).

[0090] Specifically, please refer to Figure 3, the light-emitting device 100 further includes a hole injection layer 301, a first hole transport layer 302, a second hole transport layer 305, a second hole blocking layer 306, a second electron transport layer 307, an electron injection layer 308, and an optical coupling layer 309. The hole injection layer 301 is disposed on a side of the first electrode layer 110 close to the first light-emitting layer 120. The first hole transport layer 302 is disposed on a side of the hole injection layer 301 close to the first light-emitting layer 120. The second hole transport layer 305 is disposed on a side of the P-type charge generation layer 132 close to the second light-emitting layer 140. The second hole blocking layer 306 is disposed on a side of the second light-emitting layer 140 close to the second electrode. The second electron transport layer 307 is disposed on a side of the second hole blocking layer 306 close to the second electrode. The electron injection layer 308 is disposed between the second electron transport layer 307 and the second electrode. The optical coupling layer 309 is disposed on a side of the second electrode close to the encapsulation layer 160.

[0091] In some embodiments, please refer to Figure 3 , the first light-emitting layer 120 further includes a first auxiliary light-emitting layer 122 located on a side of the first main light-emitting layer 121 close to the first electrode layer 110. The second light-emitting layer 140 further includes a second auxiliary light-emitting layer 142 located on a side of the second main light-emitting layer 141 close to the first light-emitting layer 120. Among them, the first main light-emitting layer 121 further includes at least one of a red first sub-main light-emitting layer 1211, a green first sub-main light-emitting layer 1212, and a blue first sub-main light-emitting layer 1213. The first auxiliary light-emitting layer 122 further includes at least one of a red first sub-auxiliary light-emitting layer 1221, a green first sub-auxiliary light-emitting layer 1222, and a blue first sub-auxiliary light-emitting layer 1223. The second main light-emitting layer 141 further includes at least two of a red second sub-main light-emitting layer 1411, a green second sub-main light-emitting layer 1412, and a blue second sub-main light-emitting layer 1413. The second auxiliary light-emitting layer 142 further includes at least two of a red second sub-auxiliary light-emitting layer 1421, a green second sub-auxiliary light-emitting layer 1422, and a blue second sub-auxiliary light-emitting layer 1423. Among them, the first sub-main light-emitting layer, the first sub-auxiliary light-emitting layer, the second sub-main light-emitting layer, and the second sub-auxiliary light-emitting layer of the same color correspond to each other in a direction perpendicular to the driving substrate 101.

[0092] Further, the thicknesses of the sub-auxiliary light-emitting layers of the first auxiliary light-emitting layer 122 and / or the second auxiliary light-emitting layer 142 in a direction perpendicular to the driving substrate 101 are the same or different. Please refer to Figure 3 the second light-emitting layer 140 in Figure 3In the first light-emitting layer 120, the thicknesses of the red first sub-assist light-emitting layer 1221, the green first sub-assist light-emitting layer 1222, and the blue first sub-assist light-emitting layer 1223 can be adjusted. By setting the thicknesses of the three to be the same, the first sub-assist light-emitting layer and the first main body light-emitting layer of the same color can be formed by evaporation in the same evaporation chamber, so as to reduce the number of evaporation chambers occupied in the manufacturing process of the light-emitting device 100, further simplify the process, and reduce costs.

[0093] In some other embodiments, the thicknesses of the red first sub-assist light-emitting layer 1221, the green first sub-assist light-emitting layer 1222, and the blue first sub-assist light-emitting layer 1223 in the first light-emitting layer 120 can also be set to be different; the thicknesses of the red second sub-assist light-emitting layer 1421, the green second sub-assist light-emitting layer 1422, and the blue second sub-assist light-emitting layer 1423 in the second light-emitting layer 140 can also be set to be the same, which is not limited in this application.

[0094] This application also provides a manufacturing method of a light-emitting device 100. The manufacturing method of the light-emitting device 100 includes:

[0095] Forming a first electrode layer 110;

[0096] Forming a first light-emitting layer 120 above the first electrode layer 110;

[0097] Forming a buffer layer 200 and an N-type charge generation layer 131 in sequence on the side of the first light-emitting layer 120 away from the first electrode layer 110, and the buffer layer 200 and the N-type charge generation layer 131 are formed in the same evaporation chamber. Among them, the N-type charge generation layer 131 includes a first N-type electron transport material, and the buffer layer 200 includes at least one sub-buffer layer. The sub-buffer layer includes at least one of a hole blocking material, an electron transport material, and a second N-type electron transport material;

[0098] Forming a P-type charge generation layer 132 on the side of the N-type charge generation layer 131 away from the buffer layer 200, where the P-type charge generation layer 132 and the N-type charge generation layer 131 constitute a connection layer 130;

[0099] Forming a second light-emitting layer 140 on the side of the connection layer 130 away from the buffer layer 200; and

[0100] Forming a second electrode layer 150 on the side of the second light-emitting layer 140 away from the connection layer 130.

[0101] The evaporation chamber can include multiple evaporation sources. For example, the evaporation chamber can include 2 evaporation sources, 3 evaporation sources, 4 evaporation sources, or more evaporation sources. The number of evaporation sources in the evaporation chamber can be adjusted and matched according to the number of film layers of the buffer layer 200 and the material of the sub-buffer layer.

[0102] Please refer to Figure 13 , taking the evaporation method with one cavity and three sources as an example, the evaporation chamber includes a first evaporation source, a second evaporation source, and a third evaporation source. The first evaporation source is configured to evaporate one of a hole blocking material, an electron transport material, and a second N-type electron transport material. The second evaporation source is configured to evaporate a first N-type electron transport material. The third evaporation source is configured to evaporate a first doped metal. Among them, the materials of the first evaporation source, the second evaporation source, and the third evaporation source can be replaced with each other, or the positions of the first evaporation source, the second evaporation source, and the third evaporation source in the evaporation chamber can be replaced with each other, which is not limited in this application.

[0103] In some embodiments, the buffer layer 200 includes a first sub-buffer layer 201, and the first sub-buffer layer 201 includes a hole blocking material. The buffer layer 200 and the N-type charge generation layer 131 are formed in the same evaporation chamber. Taking the evaporation method with one cavity and three sources as an example, the evaporation chamber includes a first evaporation source S1, a second evaporation source S2, and a third evaporation source S3. The positions of S1, S2, and S3 in the evaporation chamber can be replaced with each other. The first evaporation source S1 includes a hole blocking material, the second evaporation source S2 includes a first N-type electron transport material, and the third evaporation source S3 includes a first doped metal. Among them, the first evaporation source S1 is used to evaporate and form the first sub-buffer layer 201, and the second evaporation source S2 and the third evaporation source S3 are used to evaporate and form the N-type charge generation layer 131. The buffer layer 200 and the N-type charge generation layer 131 adopt a single-cavity evaporation method, which can reduce the number of evaporation chambers occupied during the manufacturing process of the light-emitting device 100, simplify the process, and reduce the cost.

[0104] In some embodiments, the buffer layer 200 includes a second sub-buffer layer 202, and the second sub-buffer layer 202 includes a second N-type electron transport material. The buffer layer 200 and the N-type charge generation layer 131 are formed in the same evaporation chamber. Taking the evaporation method with one cavity and three sources as an example, the evaporation chamber includes a first evaporation source S1, a second evaporation source S2, and a third evaporation source S3. The positions of S1, S2, and S3 in the evaporation chamber can be replaced with each other. The first evaporation source S1 includes a second N-type electron transport material, the second evaporation source S2 includes a first N-type electron transport material, and the third evaporation source S3 includes a first doped metal. Among them, the first evaporation source S1 is used to evaporate and form the second sub-buffer layer 202, and the second evaporation source S2 and the third evaporation source S3 are used to evaporate and form the N-type charge generation layer 131.

[0105] In some embodiments, the buffer layer 200 includes a first sub-buffer layer 201 and a second sub-buffer layer 202. The second sub-buffer layer 202 is disposed between the first sub-buffer layer 201 and the N-type charge generation layer 131. The first sub-buffer layer 201 includes a hole blocking material, and the second sub-buffer layer 202 includes a second N-type electron transport material. The buffer layer 200 and the N-type charge generation layer 131 are formed in the same evaporation chamber. Taking the evaporation method of one chamber with three sources as an example, the evaporation chamber includes a first evaporation source S1, a second evaporation source S2, and a third evaporation source S3. The positions of S1, S2, and S3 in the evaporation chamber can be interchanged. The first evaporation source S1 includes a hole blocking material, and the second evaporation source S2 includes a first N-type electron transport material or a second N-type electron transport material. At this time, due to the use of the one chamber with three sources method, the second N-type electron transport material is the same as the first N-type electron transport material. The third evaporation source S3 includes a first doped metal. Among them, the first evaporation source S1 is used to evaporate and form the first sub-buffer layer 201, and the second evaporation source S2 and the third evaporation source S3 are used to evaporate and form the N-type charge generation layer 131.

[0106] In some embodiments, the buffer layer 200 includes a third sub-buffer layer 203. The third sub-buffer layer 203 includes an electron transport material. The buffer layer 200 and the N-type charge generation layer 131 are formed in the same evaporation chamber. Taking the evaporation method of one chamber with three sources as an example, the evaporation chamber includes a first evaporation source S1, a second evaporation source S2, and a third evaporation source S3. The positions of S1, S2, and S3 in the evaporation chamber can be interchanged. The first evaporation source S1 includes an electron transport material, the second evaporation source S2 includes a first N-type electron transport material, and the third evaporation source S3 includes a first doped metal. Among them, the first evaporation source S1 is used to evaporate and form the third sub-buffer layer 203, and the second evaporation source S2 and the third evaporation source S3 are used to evaporate and form the N-type charge generation layer 131.

[0107] In some embodiments, the buffer layer 200 includes a third sub-buffer layer 203. The third sub-buffer layer 203 includes an electron transport material and a second doped metal. The buffer layer 200 and the N-type charge generation layer 131 are formed in the same evaporation chamber. Taking the evaporation method of one chamber with three sources as an example, the evaporation chamber includes a first evaporation source S1, a second evaporation source S2, and a third evaporation source S3. The positions of S1, S2, and S3 in the evaporation chamber can be interchanged. The first evaporation source S1 includes an electron transport material, and the second evaporation source S2 includes a first doped metal or a second doped metal. At this time, due to the use of the one chamber with three sources method, the second doped metal is the same as the first doped metal in material. The third evaporation source S3 includes a first N-type electron transport material. Among them, the first evaporation source S1 and the second evaporation source S2 are used to evaporate and form the third sub-buffer layer 203, and the second evaporation source S2 and the third evaporation source S3 are used to evaporate and form the N-type charge generation layer 131.

[0108] In some embodiments, the buffer layer 200 includes a fourth sub-buffer layer 204, and the fourth sub-buffer layer 204 includes a second N-type electron transport material and a third doped metal. The buffer layer 200 and the N-type charge generation layer 131 are formed in the same evaporation chamber. Taking the evaporation method with one chamber and three sources as an example, the evaporation chamber includes a first evaporation source S1, a second evaporation source S2, and a third evaporation source S3. The positions of S1, S2, and S3 in the evaporation chamber can be interchanged. The first evaporation source S1 includes a second N-type electron transport material, the second evaporation source S2 includes a first doped metal or a third doped metal. At this time, due to the use of the one-chamber three-source method, the third doped metal has the same material as the first doped metal, and the third evaporation source S3 includes a first N-type electron transport material. Among them, the first evaporation source S1 and the second evaporation source S2 are used for evaporating and forming the fourth sub-buffer layer 204, and the second evaporation source S2 and the third evaporation source S3 are used for evaporating and forming the N-type charge generation layer 131.

[0109] In some embodiments, the buffer layer 200 includes a second sub-buffer layer 202 and a fourth sub-buffer layer 204. The second sub-buffer layer 202 is disposed between the fourth sub-buffer layer and the first light-emitting layer 120. The second sub-buffer layer 202 includes a second N-type electron transport material, and the fourth sub-buffer layer 204 includes a second N-type electron transport material and a third doped metal. The buffer layer 200 and the N-type charge generation layer 131 are formed in the same evaporation chamber. Taking the evaporation method with one chamber and three sources as an example, the evaporation chamber includes a first evaporation source S1, a second evaporation source S2, and a third evaporation source S3. The positions of S1, S2, and S3 in the evaporation chamber can be interchanged. The first evaporation source S1 includes a second N-type electron transport material, the second evaporation source S2 includes a first doped metal or a third doped metal. At this time, due to the use of the one-chamber three-source method, the third doped metal has the same material as the first doped metal, and the third evaporation source S3 includes a first N-type electron transport material. Among them, the first evaporation source S1 is used for forming the second sub-buffer layer 202, the first evaporation source S1 and the second evaporation source S2 are used for evaporating and forming the fourth sub-buffer layer 204, and the second evaporation source S2 and the third evaporation source S3 are used for evaporating the N-type charge generation layer 131.

[0110] The present application provides a light-emitting device and a method for manufacturing the light-emitting device. The light-emitting device of the present application uses a buffer layer to replace the hole blocking layer and the electron transport layer in the existing Tandem OLED device structure, so as to simplify the Tandem OLED structure, and enable the buffer layer and the adjacent N-type charge generation layer to complete the film evaporation in the same evaporation chamber, that is, the buffer layer and the N-type charge generation layer are formed by single-chamber evaporation. Compared with the structure in which the existing hole blocking layer, electron transport layer and N-type charge generation layer need to complete the film evaporation through multiple evaporation chambers, the present application reduces the number of occupied evaporation chambers, simplifies the process, and can effectively reduce the cost. At the same time, the buffer layer of the present application may include at least one sub-buffer layer, and the sub-buffer layer includes at least one of a hole blocking material, an electron transport material, and a second N-type electron transport material. By adjusting the number of film layers of the buffer layer and the combination of the sub-buffer layer materials, the requirements of different device structures for the functions of the buffer layer are met, so as to maintain or further improve the performance of the existing Tandem OLED device.

[0111] In the description of the present application, the terms "first" and "second" are only used for descriptive purposes, and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more features. In the description of the present application, "a plurality" means two or more, unless otherwise specifically defined.

[0112] In the above embodiments, the descriptions of the respective embodiments have their own emphases. For the parts not detailed in a certain embodiment, reference may be made to the relevant descriptions of other embodiments.

[0113] Among the embodiments, implementation manners and related technical features of the present application, they can be combined and replaced with each other without conflict.

[0114] The above are only the preferred embodiments of the present application, and do not impose any form of limitation on the present application. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present application without departing from the content of the technical solution of the present application still fall within the scope of the technical solution of the present application.

Claims

1. A light emitting device, characterized in that: include: a first electrode layer; A first light-emitting layer, disposed above the first electrode layer; A buffer layer is arranged on a side of the first light-emitting layer away from the first electrode layer; a connecting layer, arranged on a side of the buffer layer away from the first light-emitting layer, the connecting layer comprising a P-type charge generation layer and an N-type charge generation layer, the N-type charge generation layer being located between the P-type charge generation layer and the buffer layer, and the N-type charge generation layer comprising a first N-type electron transport material; A second light-emitting layer is arranged on a side of the connecting layer away from the buffer layer; as well as A second electrode layer is arranged on a side of the second light-emitting layer away from the connecting layer; The buffer layer includes at least one sub-buffer layer, and the sub-buffer layer includes at least one of a hole blocking material, an electron transport material and a second N-type electron transport material.

2. The light emitting device according to claim 1, characterized in that: The buffer layer includes a first sub-buffer layer, and the first sub-buffer layer includes the hole blocking material; The lowest unoccupied molecular orbital energy level of the first N-type electron transport material is greater than the lowest unoccupied molecular orbital energy level of the hole blocking material.

3. The light emitting device according to claim 1, characterized in that: The buffer layer includes a second sub-buffer layer, and the second sub-buffer layer includes the second N-type electron transport material; The first light-emitting layer includes a first organic light-emitting material; The highest occupied molecular orbital energy level of the first N-type electron transport material and / or the second N-type electron transport material is greater than the highest occupied molecular orbital energy level of the first organic light-emitting material.

4. The light emitting device according to claim 1, characterized in that: The buffer layer includes a first sub-buffer layer and a second sub-buffer layer, the second sub-buffer layer is arranged between the first sub-buffer layer and the N-type charge generation layer, the first sub-buffer layer includes the hole blocking material, and the second sub-buffer layer includes the second N-type electron transport material, and the second N-type electron transport material is the same as the first N-type electron transport material; The lowest unoccupied molecular orbital energy level of the second N-type electron transport material is greater than the lowest unoccupied molecular orbital energy level of the hole blocking material.

5. The light emitting device according to claim 1, characterized in that: The buffer layer includes a third sub-buffer layer, and the third sub-buffer layer includes the electron transport material; The first light-emitting layer includes a first organic light-emitting material; The highest occupied molecular orbital energy level of the first N-type electron transport material and / or the electron transport material is greater than the highest occupied molecular orbital energy level of the first organic light-emitting material.

6. The light emitting device according to claim 1, characterized in that: The N-type charge generation layer further includes a first doped metal; The buffer layer includes a third sub-buffer layer, and the third sub-buffer layer includes the electron transport material and a second doping metal, wherein the second doping metal is made of the same material as the first doping metal.

7. The light emitting device according to claim 1, characterized in that: The N-type charge generation layer further includes a first doped metal; The buffer layer includes a fourth sub-buffer layer, the fourth sub-buffer layer includes the second N-type electron transport material and a third doped metal, and the third doped metal is the same as the first doped metal; A doping concentration of the third doping metal in the fourth sub-buffer layer is greater than a doping concentration of the first doping metal in the N-type charge generation layer.

8. The light emitting device according to claim 7, characterized in that: The buffer layer further includes a second sub-buffer layer, the second sub-buffer layer is disposed between the fourth sub-buffer layer and the first light-emitting layer, and the second sub-buffer layer includes the second N-type electron transport material.

9. A method for manufacturing a light emitting device, characterized in that: include: forming a first electrode layer; forming a first light-emitting layer above the first electrode layer; A buffer layer and an N-type charge generation layer are sequentially formed on a side of the first light-emitting layer away from the first electrode layer, and the buffer layer and the N-type charge generation layer are formed in the same evaporation chamber, wherein the N-type charge generation layer includes a first N-type electron transport material, the buffer layer includes at least one sub-buffer layer, and the sub-buffer layer includes at least one of a hole blocking material, an electron transport material, and a second N-type electron transport material; forming a P-type charge generation layer on a side of the N-type charge generation layer away from the buffer layer, wherein the P-type charge generation layer and the N-type charge generation layer constitute a connection layer; forming a second light-emitting layer on a side of the connecting layer away from the buffer layer; and A second electrode layer is formed on a side of the second light emitting layer away from the connecting layer.

10. The method for manufacturing a light emitting device according to claim 9, characterized in that: The N-type charge generation layer further includes a first doped metal; The evaporation chamber includes a first evaporation source, a second evaporation source and a third evaporation source, the first evaporation source is configured to evaporate one of the hole blocking material, the electron transport material and the second N-type electron transport material, the second evaporation source is configured to evaporate the first N-type electron transport material, and the third evaporation source is configured to evaporate the first doped metal.

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