Display device and method of manufacturing the same

Abstract

The application relates to a display device and a manufacturing method thereof. The display device comprises a substrate, a first electrode layer, a first pixel defining layer, a first light emitting unit, a charge generating layer, a second pixel defining layer, a second light emitting unit and a second electrode layer. The first pixel defining layer is arranged on the substrate, and the first pixel defining layer defines a first pixel pit which exposes the first electrode layer; the first light emitting unit is arranged in the first pixel pit and on the first electrode layer; the first pixel pit formed by the first pixel defining layer is used for arranging the first light emitting unit, the second pixel pit formed by the second pixel defining layer is used for arranging the second light emitting unit, the second pixel defining layer is arranged on the first pixel defining layer of the charge generating layer and covers at least part of the charge generating layer on the first surface, so that the liquid repellency of the pixel defining layer is not damaged due to the existence of the charge generating layer, and the color mixing problem caused by ink drop overflow can be avoided during the manufacturing of the second light emitting unit.

Description

Technical Field

[0001] This invention relates to the field of display technology, and in particular to a display device and its manufacturing method. Background Technology

[0002] Organic light-emitting diodes (OLEDs) possess advantages such as self-illumination, high contrast, and the ability to achieve ultra-lightweight, ultra-thin, and flexible designs, making them a highly anticipated display technology. Quantum dot light-emitting diodes (QLEDs) offer advantages such as saturated emitted light color, tunable wavelength, and high quantum yield, making them a strong competitor to OLEDs in recent years. Currently, the main fabrication methods for OLEDs and QLEDs are vacuum evaporation and solution printing. Compared to evaporation, printing technology offers advantages such as not requiring high vacuum, lower equipment costs, simpler processes, and less material consumption, thus becoming a key focus for the development of medium- and large-sized display technologies. However, existing printing technologies suffer from low device efficiency and poor lifespan, especially for blue devices, where brightness and luminous efficiency are low, and the performance of single-layer printed blue devices is insufficient to meet the performance requirements of medium-sized flat panels.

[0003] Stacked devices connect two or more unit devices in series through a charge generation layer (CGL), which can effectively improve brightness and luminous efficiency, and also achieve high brightness at low current density, thereby extending the lifespan of stacked devices.

[0004] When fabricating multilayer devices using printing methods, pixel pits are formed through a pixel defining layer to define the ink deposition area. To prevent inks of different colors from mixing in adjacent pixel pits, the upper surface of the pixel defining layer is usually made hydrophobic, allowing the ink to fall more effectively into the corresponding pixel pit. However, the charge generation layer is generally prepared by evaporation or sputtering. When the charge generation layer covers the pixel defining layer, it disrupts the hydrophobicity of the pixel defining layer surface, easily causing ink droplets to overflow and resulting in pixel color mixing. Summary of the Invention

[0005] Therefore, it is necessary to provide a display device and its manufacturing method to solve the problem of the charge generation layer damaging the hydrophobicity of the pixel boundary layer surface.

[0006] One objective of this invention is to provide a display device, the solution of which is as follows:

[0007] A display device, comprising:

[0008] substrate;

[0009] A first electrode layer is disposed on the substrate;

[0010] A first pixel defining layer is disposed on the substrate, the first pixel defining layer defines a first pixel pit, and the first pixel pit exposes the first electrode layer;

[0011] The first light-emitting unit is located on the first electrode layer in the first pixel pit;

[0012] A charge generation layer is disposed on the first light-emitting unit and extends to a first surface of the first pixel defining layer on the side away from the substrate;

[0013] A second pixel defining layer is disposed on the first pixel defining layer and at least partially covers the charge generating layer on the first surface. The second pixel defining layer defines a second pixel pit, and the second pixel pit exposes the charge generating layer.

[0014] The second light-emitting unit is located on the charge-generating layer in the second pixel pit; and

[0015] The second electrode layer is disposed on the second light-emitting unit.

[0016] In one embodiment, the charge generation layer includes a first part and a second part connected together, the first part being disposed on the first light-emitting unit, and the second part being disposed on the first surface of the first pixel defining layer.

[0017] In one embodiment, the second pixel defining layer is located on the second part.

[0018] In one embodiment, the charge generation layer includes an N-type charge generation layer and a P-type charge generation layer sequentially stacked on the first light-emitting unit;

[0019] The first electrode layer is one of the anode layer and the cathode layer, and the second electrode layer is the other of the cathode layer and the cathode layer. The N-type charge generation layer is closer to the anode layer than the P-type charge generation layer.

[0020] In one embodiment, the material of the N-type charge generation layer is selected from at least one of alkali metals and their oxides, alkaline earth metals and their oxides, lanthanide metals and their oxides, and organic materials doped with N-type dopants.

[0021] The alkali metal is selected from at least one of Li, Na, K, Rb, and Cs;

[0022] The alkaline earth metal is selected from at least one of Mg, Ca and Ba;

[0023] The lanthanide metal is selected from at least one of Sm, Eu, Tb and Yb;

[0024] In the organic material doped with an N-type dopant, the N-type dopant is selected from at least one of alkali metals, alkali metal compounds, alkaline earth metals, and alkaline earth metal compounds, and the organic material is selected from at least one of tris(8-hydroxyquinoline)aluminum, hydroxyquinoline derivatives, triazine, indole derivatives, and thiophene derivatives.

[0025] The material of the P-type charge generation layer is at least one of transition metal oxides and organic materials doped with P-type dopants.

[0026] The transition metal in the transition metal oxide is selected from at least one of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, In, Sn, Ge, Y, Mo, Ta, and W;

[0027] In the organic material doped with a P-type dopant, the P-type dopant is selected from at least one of F4-TCNQ, MoO3, FeCl3, and HATCN, and the organic material is selected from at least one of aromatic amines and their derivatives.

[0028] In one embodiment, the materials of the first pixel defining layer and the second pixel defining layer are each independently fluorinated resin.

[0029] In one embodiment, the cross-sections of the first pixel defining layer and the second pixel defining layer are trapezoidal.

[0030] In one embodiment, the orthographic projection of the first pixel pit on the substrate lies within the orthographic projection of the second pixel pit on the substrate.

[0031] In one embodiment, the first light-emitting unit includes a first light-emitting layer, and the second light-emitting unit includes a second light-emitting layer, wherein the first light-emitting layer and the second light-emitting layer are respectively independently organic light-emitting layers or quantum dot light-emitting layers;

[0032] The organic light-emitting layer is made of at least one of fluorescent light-emitting materials, phosphorescent light-emitting materials, TADF light-emitting materials, and superfluorescent light-emitting materials. The quantum dot light-emitting layer is made of compounds from groups II-VI, III-V, IV-VI, group IV elements or compounds, group II-III-VI, group I-III-VI, group I-II-IV-VI, or combinations thereof.

[0033] In one embodiment, the first light-emitting unit further includes a first charge-carrier functional layer and a second charge-carrier functional layer, wherein the first charge-carrier functional layer is disposed between the first electrode layer and the first light-emitting layer, and the second charge-carrier functional layer is disposed between the first light-emitting layer and the charge-generating layer; and / or

[0034] The second light-emitting unit further includes a third carrier functional layer and a fourth carrier functional layer. The second carrier functional layer is disposed between the charge generation layer and the second light-emitting layer, and the fourth carrier functional layer is disposed between the second light-emitting layer and the second electrode layer.

[0035] Another object of the present invention is to provide a method for manufacturing a display device, the solution of which is as follows:

[0036] A method for manufacturing a display device, characterized by comprising the following steps:

[0037] A substrate having a first electrode layer is provided;

[0038] A first pixel defining layer is formed on the substrate, the first pixel defining layer defines a first pixel pit, and the first pixel pit exposes the first electrode layer;

[0039] A first light-emitting unit is fabricated in the first pixel pit, and the first light-emitting unit is formed on the first electrode layer;

[0040] A charge generation layer is formed on the first light-emitting unit and extends to a first surface of the first pixel defining layer on the side away from the substrate;

[0041] A second pixel defining layer is formed on the first pixel defining layer and at least partially covers the charge generating layer on the first surface. The second pixel defining layer defines a second pixel pit, which exposes the charge generating layer.

[0042] A second light-emitting unit is fabricated in the second pixel pit;

[0043] A second electrode layer is fabricated on the second light-emitting unit.

[0044] In comparison, the above-mentioned display devices and their manufacturing methods have the following advantages:

[0045] The aforementioned display device and its manufacturing method employ a stacked first and second light-emitting unit to emit light together, which improves device efficiency and lifespan. A charge-generating layer is placed between the first and second light-emitting units, effectively enhancing brightness and luminous efficiency, and achieving high brightness at low current density, thereby extending the lifespan of the stacked device. The display device also includes a first pixel-defining layer and a second pixel-defining layer. The first pixel pit formed by the first pixel-defining layer is used to house the first light-emitting unit, and the second pixel pit formed by the second pixel-defining layer is used to house the second light-emitting unit. The second pixel-defining layer is disposed on the first pixel-defining layer of the charge-generating layer, and at least a portion of it covers the charge-generating layer on the first surface, i.e., it is located in a non-pixel area. This prevents the presence of the charge-generating layer from compromising the hydrophobicity of the pixel-defining layer, thus avoiding color mixing problems caused by ink droplet overflow during subsequent fabrication of the second light-emitting unit. Attached Figure Description

[0046] Figure 1 This is a schematic diagram of the structure of a display device according to one embodiment;

[0047] Figure 2 for Figure 1 The diagram shows the structure of the first light-emitting functional layer in the display device.

[0048] Figure 3 for Figure 1 The diagram shown is a schematic representation of the charge generation layer in the display device.

[0049] Figure 4 This is a schematic flowchart illustrating a method for manufacturing a display device according to one embodiment.

[0050] Explanation of reference numerals in the attached figures:

[0051] 100. Display device; 110. Substrate; 120. First electrode layer; 130. First pixel defining layer; 140. First light-emitting functional layer; 141. First light-emitting material layer; 142. Electron transport layer; 143. Hole transport layer; 144. Hole injection layer; 150. Charge generation layer; 151. First part; 152. Second part; 153. N-type charge generation layer; 154. P-type charge generation layer; 160. Second pixel defining layer; 170. Second light-emitting functional layer; 180. Second electrode layer. Detailed Implementation

[0052] To facilitate understanding of the present invention, a more comprehensive description will be given below. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the present invention.

[0053] It should be noted that when an element is referred to as being "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0054] In the description of this invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature.

[0055] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0056] This invention provides a display device.

[0057] Please refer to Figure 1 As shown, a display device 100 according to an embodiment of the present invention includes a substrate 110, a first electrode layer 120, a first pixel defining layer 130, a first light-emitting unit 140, a charge generating layer 150, a second pixel defining layer 160, a second light-emitting unit 170, and a second electrode layer 180.

[0058] A first electrode layer 120 is disposed on a substrate 110. A first pixel defining layer 130 is disposed on the substrate 110, defining a first pixel pit, the first pixel pit exposing the first electrode layer 120. It is understood that there are multiple first pixel pits, arranged in an array. A first light-emitting unit 140 is located on the first electrode layer 120 of the first pixel pit. A charge-generating layer 150 is disposed on the first light-emitting unit 140 and extends to a first surface of the first pixel defining layer 130 on the side away from the substrate 110. A second pixel defining layer 160 is disposed on the first pixel defining layer 130 and at least partially covers the charge-generating layer 150 on the first surface. The second pixel defining layer 160 defines a second pixel pit, the second pixel pit exposing the charge-generating layer 150. A second light-emitting unit 170 is located in the second pixel pit and disposed on the charge-generating layer 150. A second electrode layer 180 is disposed on the second light-emitting unit 170.

[0059] The aforementioned display device 100 is provided with a first light-emitting unit 140 and a second light-emitting unit 170 stacked together to emit light, which can improve device efficiency and lifespan. A charge generation layer 150 is provided between the first light-emitting unit 140 and the second light-emitting unit 170, which can effectively improve brightness and luminous efficiency, and can also achieve high brightness under low current density, thereby improving the lifespan of the stacked device.

[0060] The aforementioned display device 100 is further provided with a first pixel defining layer 130 and a second pixel defining layer 160. The first pixel pit formed by the first pixel defining layer 130 is used to set the first light-emitting unit 140, and the second pixel pit formed by the second pixel defining layer 160 is used to set the second light-emitting unit 170. The second pixel defining layer 160 is disposed on the first pixel defining layer 130 and at least a portion of it covers the charge generation layer 150 on the first surface, i.e., it is located in the non-pixel area. This avoids the damage to the hydrophobicity of the pixel defining layer due to the presence of the charge generation layer 150, and can prevent color mixing caused by ink droplet overflow when the second light-emitting unit 170 is subsequently manufactured.

[0061] The substrate 110 includes a substrate and a TFT driving array disposed on the substrate. The substrate can be a rigid substrate, such as glass or ceramic, or a flexible substrate, such as PC (polycarbonate), PI (polyimide) and its derivatives, PEN (polyethylene naphthalate), PEP (phosphoenolpyruvate), diphenylene ether resin, etc.

[0062] The first electrode layer 120 is a patterned conductive material layer. The first electrode layer 120 can be an anode layer for providing hole carriers or a cathode layer for providing electron carriers. Specifically, the anode layer can be selected from one or more of indium tin oxide, zinc tin oxide, indium zinc oxide, zinc oxide, graphene, and carbon nanotubes. The cathode layer can use conventional cathode materials, including at least one of Al, Ag, Cu, Au, Mg, Ca, and alloys formed from Al, Ag, Cu, Au, Mg, and Ca. More specifically, the first electrode layer 120 can be a transparent electrode layer, for example, formed using a transparent conductive material with a relatively large work function, including but not limited to indium tin oxide (ITO), zinc tin oxide (ZTO), indium zinc oxide (IZO), zinc oxide, gallium indium zinc oxide (GIZO), etc. Furthermore, the first electrode layer 120 can also be a composite layer including a transparent conductive material layer and a metal layer, such as an ITO / Ag / ITO composite layer.

[0063] The first pixel defining layer 130 has first pixel pits that define the ink deposition area of ​​the first light-emitting unit 140. The first pixel defining layer 130 is preferably made of a hydrophobic material, such as a fluorinated resin, to avoid ink mixing problems during printing. In one example, the material of the first pixel defining layer 130 is a fluorinated resin with hydrophobic fluorine groups. The first pixel defining layer 130 can be fabricated using a photolithography process, specifically including steps such as coating, exposure, development, and baking.

[0064] In one example, the cross-section of the first pixel defining layer 130 is trapezoidal, and in the illustrated example, it is an isosceles trapezoid.

[0065] The first light-emitting unit 140 has a first light-emitting layer, which contains a first light-emitting material that can be an organic light-emitting material, such as PFO (poly(9,9-di-n-octylfluorenyl-2,7-diyl)), or a quantum dot light-emitting material, such as CdSe / ZnS. The first light-emitting layer may include one or more of a red light-emitting layer, a green light-emitting layer, and a blue light-emitting layer.

[0066] Understandably, the first light-emitting unit 140 may further include a carrier functional layer, such as one or more of a hole injection layer, a hole transport layer, an electron transport layer, and an electron injection layer. In one example, the first light-emitting unit further includes a first carrier functional layer and a second carrier functional layer, the first carrier functional layer being disposed between the first electrode layer and the first light-emitting layer, and the second carrier functional layer being disposed between the first light-emitting layer and the charge generation layer.

[0067] The hole injection material can be a conductive polymer, such as PEDOT:PSS; or it can be an n-type semiconductor with a high work function, such as HAT-CN, MoO3, WO3, V2O5, Rb2O, etc.

[0068] Hole transport materials can be inorganic semiconductors, such as NiO and Cu2O; or organic semiconductors, such as TFB, NPB, TAPC, TCTA, and CBP.

[0069] Electron transport materials can be inorganic semiconductors, such as ZnO, TiO2, SnO2, etc.; or organic semiconductors, such as TPBi, Bphen, TmPyPb, B3PYMPM, BCP, etc.

[0070] Electron injection materials can be alkali metal salts, such as LiF, NaF, CsF, Cs₂CO₃, etc.; or they can be low work function metals, such as Mg, Mg:Ag alloys, Yb, etc. Please refer to... Figure 2As shown, in one example, the first light-emitting unit 140 includes an electron transport layer 142, a first light-emitting material layer 141, a hole transport layer 143, and a hole injection layer 144, which are stacked sequentially. The electron transport layer is disposed between the first light-emitting material layer and the charge generation layer 150, and the hole injection layer is disposed between the hole transport layer and the first electrode layer 120.

[0071] The charge generation layer 150 has electron transport and hole transport capabilities, which can effectively improve brightness and luminous efficiency, and also achieve high brightness at low current density, thereby improving the service life of the stacked device.

[0072] Please combine Figure 3 As shown, in one example, the charge generation layer 150 includes an N-type charge generation layer 153 and a P-type charge generation layer 154 stacked together.

[0073] In one example, the first electrode layer 120 is the anode layer, the second electrode layer 180 is the cathode layer, that is, the display device 100 is a positive device, and the N-type charge generation layer 153 is located between the P-type charge generation layer 154 and the first electrode layer 120.

[0074] In another example, the first electrode layer 120 is a cathode layer and the second electrode layer 180 is an anode layer, that is, the display device 100 is an inverted device, and the N-type charge generation layer 153 is located between the P-type charge generation layer 154 and the second electrode layer 180.

[0075] Optionally, the material of the N-type charge generation layer 153 is selected from at least one of alkali metals and their oxides, alkaline earth metals and their oxides, lanthanide metals and their oxides, and organic materials doped with N-type dopants.

[0076] The alkali metal may be at least one of Li, Na, K, Rb, and Cs. The alkaline earth metal may be at least one of Mg, Ca, and Ba. The lanthanide metal may be at least one of Sm, Eu, Tb, and Yb.

[0077] In organic materials doped with N-type dopants, the N-type dopants may be at least one of alkali metals, alkali metal compounds, alkaline earth metals, and alkaline earth metal compounds. The alkali metals and alkaline earth metals may be of the aforementioned types. The organic materials may be at least one of tris(8-hydroxyquinoline)aluminum, hydroxyquinoline derivatives, triazine, indole derivatives, and thiophene derivatives.

[0078] In a specific example, the material of the N-type charge generation layer 153 is Alq3:Li.

[0079] Optionally, the material of the P-type charge generation layer 154 is at least one of transition metal oxides and organic materials doped with P-type dopants.

[0080] The transition metal in the transition metal oxide can be, for example, at least one of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, In, Sn, Ge, Y, Mo, Ta, and W.

[0081] In organic materials doped with P-type dopants, the P-type dopants may be at least one of F4-TCNQ, MoO3, FeCl3, and HATCN, and the organic materials may be at least one of aromatic amines and their derivatives.

[0082] In one specific example, the material of the P-type charge generation layer 154 is MoO3. In another specific example, the material of the P-type charge generation layer 154 is IZO.

[0083] In one example, the charge generation layer 150 is fabricated by vapor deposition or sputtering, which gives the charge generation layer 150 solvent-resistant properties, preventing damage to the first light-emitting unit 140 during the subsequent deposition of the second light-emitting unit 170.

[0084] In one example, the charge generation layer 150 is deposited over the entire surface, which can reduce the use of photomasks, simplify the process, and reduce production costs.

[0085] However, since the charge generation layer 150 covers the first pixel defining layer 130, it disrupts the hydrophobicity of the surface of the first pixel defining layer, easily leading to pixel color mixing problems. To solve this technical problem, the display device 100 further provides a second pixel defining layer 160. The second pixel defining layer 160 is disposed on the first pixel defining layer 130 and at least partially covers the charge generation layer 150 on the first surface, preventing the presence of the charge generation layer 150 from disrupting the hydrophobicity of the pixel defining layer.

[0086] The charge generation layer includes a first part 151 and a second part 152 connected together. The first part 151 is disposed on the first light-emitting unit 140, and the second part 152 is disposed on the first surface of the first pixel defining layer 130. Figure 1 In the specific example shown, the second pixel delimiting layer 160 is completely located on the second part 152.

[0087] The second pixel defining layer 160 is preferably made of a hydrophobic material, such as a fluorinated resin. Located in a non-pixel area, the second pixel defining layer 160, due to its ink-repellent properties, prevents ink droplet overflow and color mixing during the printing of the second light-emitting unit. In one example, the material of the second pixel defining layer 160 is a fluorinated resin with hydrophobic fluorine groups. The second pixel defining layer 160 can be fabricated using photolithography, specifically including steps such as coating, exposure, development, and baking. Alternatively, the second pixel defining layer 160 can also be fabricated using inkjet printing.

[0088] In one example, the cross-section of the second pixel defining layer 160 is trapezoidal, and in the illustrated example, it is an isosceles trapezoid.

[0089] In one example, the orthographic projection of the first pixel pit onto the substrate lies within the orthographic projection of the second pixel pit onto the substrate. That is, the opening of the second pixel pit is larger than the opening of the first pixel pit.

[0090] The second light-emitting unit 170 has a second light-emitting layer, which contains a second light-emitting material that can be an organic light-emitting material or a quantum dot light-emitting material. The second light-emitting layer may include one or more of a red light-emitting layer, a green light-emitting layer, and a blue light-emitting layer.

[0091] Understandably, the second light-emitting unit 170 may further include a carrier functional layer, such as one or more of a hole injection layer, a hole transport layer, an electron transport layer, and an electron injection layer. In one example, the second light-emitting unit includes a third carrier functional layer and a fourth carrier functional layer, the second carrier functional layer being disposed between the charge generation layer and the second light-emitting layer, and the fourth carrier functional layer being disposed between the second light-emitting layer and the second electrode layer.

[0092] The first light-emitting unit 140 includes a first light-emitting layer, and the second light-emitting unit 170 includes a second light-emitting layer. The first light-emitting layer and the second light-emitting layer are independently organic light-emitting layers or quantum dot light-emitting layers. The material of the organic light-emitting layer is not particularly limited and may include at least one of fluorescent light-emitting materials, phosphorescent light-emitting materials, TADF (thermally activated delayed fluorescence) light-emitting materials, and superfluorescent light-emitting materials. For example, materials for the organic light-emitting layer can include: Alq3 (tris(8-hydroxyquinoline)aluminum), CBP (4,4'-bis(N-carbazolyl)-1,1'-biphenyl), PVK (poly(N-vinylcarbazole)), ADN (9,10-bis(naphthyl-2-yl)anthracene), TCTA (4,4',4"-tris(carbazolyl-9-yl)triphenylamine), TPBI (1,3,5-tris(N-phenylbenzimidazolyl-2-yl)benzene), TBADN (3-tert-butyl-9,10-bis(naphthyl-2-yl)anthracene), DSA (stilbeneylarylene), E3 or CDBP (4,4'-bis(9-carbazolyl)-2, At least one of 2'-dimethylbiphenyl. The material of the organic light-emitting layer may also include dopants, the type of which is not particularly limited. Dopants can be classified as fluorescent dopants and phosphorescent dopants. Phosphorescent dopants can be metal complexes, including Ir, Pt, Os, Re, Ti, Zr, Hf, or combinations of two or more thereof, but are not limited thereto. The material of the quantum dot light-emitting layer includes group II-VI compounds, group III-V compounds, group IV-VI compounds, group IV elements or compounds, group II-III-VI compounds, group I-III-VI compounds, group I-II-IV-VI compounds, or combinations thereof.

[0093] In a specific example, the first light-emitting unit 140 and the second light-emitting unit 170 have the same structure and materials, specifically including a hole injection layer (PEDOT:PSS), a hole transport layer (PVK), a blue light emitting layer (PFO), and an electron injection layer (NaF).

[0094] In another example, the first light-emitting unit 140 and the second light-emitting unit 170 have the same structure and materials, specifically including a hole injection layer (PEDOT:PSS), a hole transport layer (ZnO), and a green quantum dot light-emitting layer (CdSe / ZnS).

[0095] The second electrode layer 180 is a conductive material layer. The second electrode layer 180 can be an anode layer to provide hole carriers, or a cathode layer to provide electron carriers. The material of the first electrode layer 120 can be a metal or its alloy, such as Al, Ag, Au, MgAg, etc. The first electrode layer 120 can also be a transparent electrode layer, such as indium tin oxide (ITO), zinc tin oxide (ZTO), indium zinc oxide (IZO), zinc oxide, gallium indium zinc oxide (GIZO), etc.

[0096] In one example, the display device 100 is a top-emitting structure. Furthermore, the display device 100 also includes a light extraction layer (not shown), which is disposed on the side of the second electrode layer 180 away from the substrate 110. The light extraction layer is made of a high-refractive-index material, which can be an organic small molecule material, such as Alq3, or an inorganic compound material, such as ZnSe.

[0097] In one example, the display device 100 also includes a packaging structure (not shown) disposed on the side of the second electrode layer 180 away from the substrate 110, which serves to prevent water and oxygen from entering the device.

[0098] Furthermore, such as Figure 4 As shown, the present invention also provides a method 200 for manufacturing a display device according to any of the above examples.

[0099] A method for manufacturing a display device according to one embodiment includes the following steps:

[0100] Step S1: Provide a substrate 110 on which a first electrode layer 120 is disposed.

[0101] Step S2: A first pixel defining layer 130 is formed on the substrate 110. The first pixel defining layer 130 defines a first pixel pit, and the first pixel pit exposes the first electrode layer 120.

[0102] Step S3: A first light-emitting unit 140 is fabricated in the first pixel pit, and the first light-emitting unit 140 is formed on the first electrode layer 120.

[0103] Step S4: Fabricate a charge generation layer 150. The charge generation layer 150 is formed on the first light-emitting unit 140 and extends to the first surface of the first pixel defining layer 130 on the side away from the substrate 110.

[0104] Step S5: Create a second pixel defining layer 160. The second pixel defining layer 160 is formed on the first pixel defining layer 130 and at least partially covers the charge generation layer 150 on the first surface. The second pixel defining layer 160 defines a second pixel pit, and the second pixel pit exposes the charge generation layer 150.

[0105] Step S6: A second light-emitting unit 170 is fabricated in the second pixel pit. The second light-emitting unit 170 is formed on the charge generation layer 150.

[0106] Step S7: Fabricate a second electrode layer 180 on the second light-emitting unit 170.

[0107] The manufacturing method of the aforementioned display device 100, which stacks a first light-emitting unit 140 and a second light-emitting unit 170 to emit light together, can improve device efficiency and lifespan. The presence of a charge-generating layer 150 between the first light-emitting unit 140 and the second light-emitting unit 170 can effectively improve brightness and luminous efficiency, and also achieve high brightness at low current density, thereby extending the lifespan of the stacked device. Furthermore, the aforementioned display device 100 also includes a first pixel-defining layer 130 and a second pixel-defining layer 160. The first pixel pit formed by the first pixel-defining layer 130 is used to set the first light-emitting unit 140, and the second pixel pit formed by the second pixel-defining layer 160 is used to set the second light-emitting unit 170. The second pixel-defining layer 160 is disposed on the first pixel-defining layer 130 and at least partially covers the charge-generating layer 150 on the first surface, i.e., it is located in a non-pixel area. This avoids the presence of the charge-generating layer 150 from damaging the hydrophobicity of the pixel-defining layer, and prevents color mixing problems caused by ink droplet overflow during the subsequent fabrication of the second light-emitting unit 170.

[0108] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0109] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A display device, characterized in that, include: substrate; A first electrode layer is disposed on the substrate; A first pixel defining layer is disposed on the substrate, the first pixel defining layer defines a first pixel pit, and the first pixel pit exposes the first electrode layer; The first light-emitting unit is located on the first electrode layer in the first pixel pit; A charge generation layer is disposed on the first light-emitting unit and extends to a first surface of the first pixel defining layer on the side away from the substrate; A second pixel defining layer is disposed on the first pixel defining layer and at least partially covers the charge generating layer on the first surface. The second pixel defining layer defines a second pixel pit, and the second pixel pit exposes the charge generating layer. The second light-emitting unit is located on the charge-generating layer in the second pixel pit; as well as The second electrode layer is disposed on the second light-emitting unit.

2. The display device as claimed in claim 1, characterized in that, The charge generation layer includes a first part and a second part connected together. The first part is disposed on the first light-emitting unit, and the second part is disposed on the first surface of the first pixel defining layer.

3. The display device as described in claim 2, characterized in that, The second pixel delimiting layer is located on the second part.

4. The display device as claimed in claim 1, characterized in that, The charge generation layer includes an N-type charge generation layer and a P-type charge generation layer sequentially stacked on the first light-emitting unit; The first electrode layer is one of the anode layer and the cathode layer, and the second electrode layer is the other of the anode layer and the cathode layer. The N-type charge generation layer is closer to the anode layer than the P-type charge generation layer.

5. The display device as described in claim 4, characterized in that, The material of the N-type charge generation layer is selected from at least one of alkali metals and their oxides, alkaline earth metals and their oxides, lanthanide metals and their oxides, and organic materials doped with N-type dopants. The alkali metal is selected from at least one of Li, Na, K, Rb, and Cs; The alkaline earth metal is selected from at least one of Mg, Ca and Ba; The lanthanide metal is selected from at least one of Sm, Eu, Tb and Yb; In the organic material doped with an N-type dopant, the N-type dopant is selected from at least one of alkali metals, alkali metal compounds, alkaline earth metals, and alkaline earth metal compounds, and the organic material is selected from at least one of tris(8-hydroxyquinoline)aluminum, hydroxyquinoline derivatives, triazine, indole derivatives, and thiophene derivatives.

6. The display device as claimed in claim 4, characterized in that, The material of the P-type charge generation layer is at least one of transition metal oxides and organic materials doped with P-type dopants. The transition metal in the transition metal oxide is selected from at least one of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, In, Sn, Ge, Y, Mo, Ta, and W; In the organic material doped with a P-type dopant, the P-type dopant is selected from at least one of F4-TCNQ, MoO3, FeCl3, and HATCN, and the organic material is selected from at least one of aromatic amines and their derivatives.

7. The display device according to any one of claims 1 to 6, characterized in that, The materials of the first pixel defining layer and the second pixel defining layer are independently fluorinated resins; and / or The cross-sections of the first pixel defining layer and the second pixel defining layer are trapezoidal; and / or The orthographic projection of the first pixel pit on the substrate is located within the orthographic projection of the second pixel pit on the substrate.

8. The display device according to any one of claims 1 to 6, characterized in that, The first light-emitting unit includes a first light-emitting layer, and the second light-emitting unit includes a second light-emitting layer. The first light-emitting layer and the second light-emitting layer are respectively independently organic light-emitting layers or quantum dot light-emitting layers. The organic light-emitting layer is made of at least one of fluorescent light-emitting materials, phosphorescent light-emitting materials, TADF light-emitting materials, and superfluorescent light-emitting materials. The quantum dot light-emitting layer is made of II-VI compounds, III-V compounds, IV-VI compounds, IV elements or compounds, II-III-VI compounds, I-III-VI compounds, I-II-IV-VI compounds, or combinations thereof.

9. The display device as claimed in claim 8, characterized in that, The first light-emitting unit further includes a first charge carrier functional layer and a second charge carrier functional layer, wherein the first charge carrier functional layer is disposed between the first electrode layer and the first light-emitting layer, and the second charge carrier functional layer is disposed between the first light-emitting layer and the charge-generating layer; and / or The second light-emitting unit further includes a third carrier functional layer and a fourth carrier functional layer. The third carrier functional layer is disposed between the charge generation layer and the second light-emitting layer, and the fourth carrier functional layer is disposed between the second light-emitting layer and the second electrode layer.

10. A method for manufacturing a display device, characterized in that, Includes the following steps: A substrate having a first electrode layer is provided; A first pixel defining layer is formed on the substrate, the first pixel defining layer defines a first pixel pit, and the first pixel pit exposes the first electrode layer; A first light-emitting unit is fabricated in the first pixel pit, and the first light-emitting unit is formed on the first electrode layer; A charge generation layer is formed on the first light-emitting unit and extends to a first surface of the first pixel defining layer on the side away from the substrate; A second pixel defining layer is formed on the first pixel defining layer and at least partially covers the charge generating layer on the first surface. The second pixel defining layer defines a second pixel pit, which exposes the charge generating layer. A second light-emitting unit is fabricated in the second pixel pit, and the second light-emitting unit is formed on the charge generation layer; A second electrode layer is fabricated on the second light-emitting unit.

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