CN112133842A

CN112133842A - Quantum dot light-emitting device, preparation method thereof and display device

Info

Publication number: CN112133842A
Application number: CN202011021745.8A
Authority: CN
Inventors: 卢志高
Original assignee: BOE Technology Group Co Ltd
Current assignee: BOE Technology Group Co Ltd
Priority date: 2020-09-25
Filing date: 2020-09-25
Publication date: 2020-12-25

Abstract

A quantum dot light emitting device, a manufacturing method thereof and a display device are provided; the LED display panel comprises a first electrode, a second electrode and a quantum dot light-emitting layer, wherein the first electrode and the second electrode are arranged oppositely, the quantum dot light-emitting layer is arranged between the first electrode and the second electrode, the first electrode is made of a water dispersion material, and a waterproof layer is formed between the first electrode and the quantum dot light-emitting layer; the quantum dot light-emitting layer can be effectively protected from water.

Description

Quantum dot light-emitting device, preparation method thereof and display device

Technical Field

The invention relates to the technical field of display, in particular to a quantum dot light-emitting device, a preparation method thereof and a display device.

Background

Quantum dots are also called semiconductor nanocrystals, are zero-dimensional nanostructures composed of a small number of atoms and having three-dimensional dimensions of usually 1nm to 100nm, have adjustable band gaps and narrow emission spectra, are widely applied to LED (light emitting diode) devices in recent years, have the advantages of self-luminescence, high color purity, low energy consumption, stable images, wide viewing angle range, rich colors and the like, are considered as a new generation of display technology following LCD and OLED (organic light emitting diode) in recent years, and have wide application prospects.

A Quantum Dot Light-Emitting Diode (QLED) is a device using Quantum dots as a Light-Emitting layer; by introducing a light emitting layer formed of quantum dots between different conductive materials, light of a desired wavelength is obtained. The QLED has the advantages of high color gamut, self-luminescence, low starting voltage, high response speed and the like, so that the QLED has wide application prospect in the display field and the illumination field, and is the current popular research direction.

Disclosure of Invention

The technical problem to be solved by the embodiments of the present invention is to provide a quantum dot light emitting device, a manufacturing method thereof, and a display device, which can effectively protect a quantum dot light emitting layer from water.

In order to solve the above technical problem, an embodiment of the present invention provides a quantum dot light emitting device, including a first electrode, a second electrode, and a quantum dot light emitting layer disposed between the first electrode and the second electrode, where the first electrode is made of an aqueous dispersion material, and a waterproof layer is formed between the first electrode and the quantum dot light emitting layer.

In an exemplary embodiment, the material of the waterproof layer is metal oxide.

In an exemplary embodiment, the metal oxide is one or more of tin metal oxide, molybdenum metal oxide, tungsten metal oxide, and nickel metal oxide.

In an exemplary embodiment, the density of the water barrier layer is greater than 99%.

In an exemplary embodiment, the water-repellent layer has a thickness of 5nm to 30 nm.

In an exemplary embodiment, an electron transport layer is disposed between the quantum dot light emitting layer and the waterproof layer, and the waterproof layer is formed on the electron transport layer.

In an exemplary embodiment, the material of the electron transport layer adopts one or a combination of several of azo compound nanoparticles, zinc oxide magnesium alloy nanoparticles, zinc oxide nanoparticles and zinc oxide aluminum alloy nanoparticles.

In an exemplary embodiment, the aqueous dispersion material is metal nanowires.

The embodiment of the invention also provides a display device which comprises the quantum dot light-emitting device.

The embodiment of the invention also provides a preparation method of the quantum dot light-emitting device, which comprises the following steps:

forming a second electrode;

forming a quantum dot light emitting layer over the second electrode;

forming a waterproof layer on the quantum dot light emitting layer;

and coating an aqueous dispersion solution on the waterproof layer, so that the aqueous dispersion solution forms a first electrode.

The embodiment of the invention provides a quantum dot light-emitting device, a preparation method thereof and a display device, wherein a quantum dot light-emitting layer is protected from water through a waterproof layer, and the phenomenon that liquid damages the quantum dot light-emitting layer in the process of forming a first electrode by using a water dispersion material is avoided.

Of course, not all of the advantages described above need to be achieved at the same time in the practice of any one product or method of the invention. Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the embodiments of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

Drawings

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

Fig. 1 is a schematic structural diagram of a quantum dot light-emitting device according to an embodiment of the present invention.

Detailed Description

The following detailed description of embodiments of the invention is provided in connection with the accompanying drawings and examples. The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention. It should be noted that the embodiments and features of the embodiments in the present application may be arbitrarily combined with each other without conflict.

In order to enable the electroluminescent element to emit light, it is generally necessary that at least one of the electrodes (the bottom electrode or/and the top electrode) is a transparent conductive electrode. The transparent conductive electrode allows light to pass through while providing a conductive path. When the bottom electrode is a transparent conductive electrode, the electroluminescent element generally emits bottom light; when the top electrode is a transparent conductive electrode, the electroluminescent element generally emits top light; when the bottom electrode and the top electrode are both transparent conductive electrodes, the electroluminescent element generally emits light from both sides.

The transparent conductive electrode generally adopts Ag or MgAg (magnesium silver) alloy as an electrode, but the Ag or MgAg (magnesium silver) alloy electrode is generally semitransparent and cannot meet the requirements of high light transmittance and low sheet resistance.

The inventor of the present application has found that the transparent conductive electrode commonly used at present is a transparent conductive oxide, such as Indium Tin Oxide (ITO), thin silver, thin aluminum, etc., and the transparent conductive oxide generally needs to be deposited by evaporation under high vacuum, but the equipment is expensive and it is difficult to manufacture large-sized panels. To overcome these problems, the transparent conductive electrode employs metal nanowires, such as silver nanowires (AgNWs). The metal nano-wire can be deposited under the water environment condition. However, since the quantum dot has high sensitivity to moisture, water treatment cannot be performed on the quantum dot light emitting layer to form a transparent conductive electrode.

The embodiment of the invention provides a quantum dot light-emitting device which comprises a first electrode, a second electrode and a quantum dot light-emitting layer, wherein the first electrode and the second electrode are oppositely arranged, the quantum dot light-emitting layer is arranged between the first electrode and the second electrode, the first electrode is made of a water dispersion material, and a waterproof layer is formed between the first electrode and the quantum dot light-emitting layer.

The embodiment of the invention provides a quantum dot light-emitting device, which carries out waterproof protection on a quantum dot light-emitting layer through a waterproof layer, and avoids the phenomenon that liquid damages the quantum dot light-emitting layer in the process of forming a first electrode by using a water dispersion material.

Fig. 1 is a schematic structural diagram of a quantum dot light-emitting device according to an embodiment of the present invention. As shown in fig. 1, the quantum dot light emitting device according to the embodiment of the present invention is top emission. The Quantum Dot light Emitting device comprises a Substrate (Substrate), a second electrode 10, a Hole Injection Layer (HIL) 11, a Hole Transport Layer (HTL) 12, a Quantum Dot light Emitting Layer (QD EML) 13, an Electron Transport Layer (ETL) 14, a waterproof Layer 15 and a first electrode 16, which are sequentially stacked. The second electrode 10 is an Anode (Anode) and the first electrode 16 is a Cathode (Cathode). The thickness of the first electrode 16 may be 5nm to 50 nm; the thickness of the hole injection layer 11 may be 5nm to 50 nm; the thickness of the hole transport layer 12 may be 5nm to 50 nm; the thickness of the quantum dot light emitting layer 13 may be 10nm to 60 nm; the thickness of the waterproof layer 15 may be 5nm to 30 nm.

In an exemplary embodiment, the waterproof layer may also be located between other film layers, as long as the waterproof layer is located on the side of the quantum dot light-emitting layer close to the first electrode, so that the waterproof layer can protect the quantum dot light-emitting layer from water. For example, a water-repellent layer may also be located between the quantum dot light-emitting layer and the electron transport layer. This embodiment is not described herein.

In an exemplary embodiment, the quantum dot light emitting device according to the embodiment of the present invention may also be a bottom emission. Wherein, the thickness of the first electrode may be 50nm to 200 nm. This embodiment is not described herein.

In the quantum dot light-emitting device according to the embodiment of the present invention, the hole transport layer 12 may play a role in promoting hole transport. The material of the hole transport layer 12 may be selected from organic materials having a hole transport ability, including, but not limited to, poly (9, 9-dioctylfluorene-CO-N- (4-butylphenyl) diphenylamine) (TFB), Polyvinylcarbazole (PVK), poly (N, N 'bis (4-butylphenyl) -N, N' -bis (phenyl) benzidine) (poly-TPD), poly (9, 9-dioctylfluorene-CO-bis-N, N-phenyl-1, 4-Phenylenediamine) (PFB), 4', 4 ″ -tris (carbazol-9-yl) triphenylamine (TCTA), 4' -bis (9-Carbazole) Biphenyl (CBP), N '-diphenyl-N, N' -bis (3-methylphenyl) -1,1 '-biphenyl-4, 4' -diamine (TPD), N '-diphenyl-N, N' - (1-naphthyl) -1,1 '-biphenyl-4, 4' -diamine (NPB), doped graphene, undoped graphene, C60. The hole transport layer 12 may also be selected from inorganic materials having hole transport capability, including but not limited to one or more of doped or undoped MoOx, VOx, WOx, CrOx, CuO, MoS2, MoSe2, WS2, WSe2, CuS, but the exemplary embodiments of the present application are not limited thereto.

In the quantum dot light-emitting device according to the embodiment of the invention, the hole injection layer 11 may facilitate injection of holes. The material of the hole injection layer 11 includes, but is not limited to, poly (3, 4-ethylenedioxythiophene) -polystyrenesulfonic acid (PEDOT: PSS), copper phthalocyanine (CuPc), 2,3,5, 6-tetrafluoro-7, 7',8,8' -tetracyanoquinodimethane (F4-TCNQ), 2,3,6,7,10, 11-hexacyano-1, 4,5,8,9, 12-Hexaazatriphenylene (HATCN), Polythienothiophene (PTT) doped with poly (perfluoroethylene-perfluoroether sulfonic acid) (PFFSA), transition metal oxides, preferably, one or more of MoO3, VO2, WO3, CrO3, CuO, and metal chalcogenide compounds, including one or more of MoS2, MoSe2, WS2, WSe2, CuS, although the exemplary embodiments of the present application are not limited thereto.

In the quantum dot light-emitting device of the embodiment of the present invention, the electron transport layer 14 receives electrons from the cathode, and can transfer the supplied electrons to the quantum dot light-emitting layer. The electron transport layer 14 also serves to facilitate the transport of electrons. The electron transport layer 14 may be made of AZO compound nanoparticles (AZO-NPs), zinc-magnesium oxide alloy nanoparticles (ZMO-NPs), zinc oxide nanoparticles (ZnO-NPs), and zinc-aluminum oxide alloy nanoparticles. The exemplary embodiments of the present application are not limited thereto.

In the quantum dot light-emitting device according to the embodiment of the present invention, the second electrode 10 is an anode, and the second electrode 10 includes an oxide material, a metal material, or an oxide and metal composite material. For example, the oxide material includes, but is not limited to, at least one or more of Indium Tin Oxide (ITO), Indium Zinc Oxide (IZO), zinc oxide (ZnO), Indium Gallium Oxide (IGO), Gallium Zinc Oxide (GZO), Indium Gallium Zinc Oxide (IGZO), indium oxide (In2O3), Aluminum Zinc Oxide (AZO), magnesium doped zinc oxide (MZO), aluminum doped magnesium oxide (AMO), antimony doped tin oxide (ATO), fluorine doped tin dioxide (FTO), fluorine phosphorus co-doped tin dioxide (FPTO). The exemplary embodiments of the present application are not limited thereto.

In the quantum dot light-emitting device according to the embodiment of the invention, the first electrode 16 is a cathode, the first electrode 16 is a transparent conductive electrode, and the material of the first electrode 16 is an aqueous dispersion material. The aqueous dispersion material may be metal nanowires, for example, silver nanowires (AgNWs), aluminum nanowires, gold nanowires, and the like may be used as the metal nanowires. The process for preparing the first electrode 16 by adopting the aqueous dispersion material is simple, the aqueous dispersion solution is only required to be spin-coated on the waterproof layer 15, other devices such as evaporation and the like are not required to be introduced, and the cost is reduced.

In the quantum dot light-emitting device of the embodiment of the present invention, the quantum dot light-emitting layer 13 is used for emitting light. The quantum dot light-emitting layer 13 can be made of light-emitting materials such as cadmium quantum dots, cadmium-free quantum dots, perovskite and the like. The exemplary embodiments of the present application are not limited thereto.

In the quantum dot light-emitting device according to the embodiment of the invention, the waterproof layer 15 is used for performing waterproof protection on the quantum dot light-emitting layer 13, so that the phenomenon that liquid damages the quantum dot light-emitting layer 13 in the process of forming the first electrode by using the aqueous dispersion material is avoided. The waterproof layer 15 is made of metal oxide. For example, the metal oxide is one or a combination of tin metal oxide, molybdenum metal oxide, tungsten metal oxide and nickel metal oxide. Wherein, the density of the waterproof layer 15 is more than 99% to ensure the waterproof performance of the waterproof layer 15.

The technical solution of this embodiment is further described below by the manufacturing process of the array substrate of this embodiment. The "patterning process" in this embodiment includes processes of depositing a film, coating a photoresist, exposing a mask, developing, etching, and stripping the photoresist, and is a well-established manufacturing process in the related art. The "photolithography process" referred to in this embodiment includes coating film coating, mask exposure, and development, and is a well-established production process in the related art. The deposition may be performed by a known process such as sputtering, evaporation, chemical vapor deposition, etc., the coating may be performed by a known coating process, and the etching may be performed by a known method, which is not particularly limited herein. In the description of the present embodiment, it is to be understood that "thin film" refers to a layer of a material deposited or coated on a substrate. The "thin film" may also be referred to as a "layer" if it does not require a patterning process or a photolithography process throughout the fabrication process. If a patterning process or a photolithography process is required for the "thin film" in the entire manufacturing process, the "thin film" is referred to as a "thin film" before the patterning process, and the "layer" after the patterning process. The "layer" after the patterning process or the photolithography process includes at least one "pattern".

As shown in fig. 1, the preparation process of the quantum dot light emitting device of this embodiment includes:

(1) coating a substrate material on the glass carrier plate, and curing to form a film to form the substrate. A second electrode 10 is then formed on the substrate. In the embodiment of the invention, the base can be a rigid substrate or a flexible substrate. Wherein the rigid substrate includes, but is not limited to, one or more of glass, metal foil or ceramic material. The flexible substrate can be made of polyimide PI, polyethylene terephthalate PET or polymer soft film with surface treatment.

(2) Spin-coating a hole injection material film on the second electrode 10 by a spin-coating process, and then annealing at a temperature of 100 to 250 ℃ to form a hole injection layer 11 from the hole injection material film; wherein the rotating speed of the spin coating is 1000-5000 r/min.

(3) A hole transport material film is spin-coated on the hole injection layer 11 through a spin coating process, and then annealing is carried out at a temperature of between 80 and 200 ℃ so that the hole transport material film forms a hole transport layer 12; wherein the rotating speed of the spin coating is 1000-5000 r/min.

(4) A quantum dot light-emitting layer material film is spin-coated on the hole transport layer 12 through a spin coating process, and then annealing is carried out at a temperature of between 100 and 200 ℃ so that the quantum dot light-emitting layer material film forms a quantum dot light-emitting layer 13; wherein the rotating speed of the spin coating is 1000-5000 r/min.

(5) Spin-coating an electron transport layer material film on the quantum dot light-emitting layer 13 by a spin-coating process, and then annealing at a temperature of 10-50 ℃ to form an electron transport layer 14 from the electron transport layer material film; wherein the rotating speed of the spin coating is 1000-4000r/min, and the time of the spin coating is 10-50 seconds.

(6) The water repellent layer 15 is formed on the electron transport layer 14 by an Atomic Layer Deposition (ALD) process. Wherein, the thickness of the waterproof layer 15 is 5nm to 30nm, and the density of the waterproof layer 15 is more than 99%.

(7) Coating an aqueous dispersion solution on the water-repellent layer 15 by a spin coating process, and then annealing at a temperature between 110 and 180 degrees for 5 to 15 minutes to form the aqueous dispersion solution into the first electrode 16; wherein, the aqueous dispersion solution can be silver metal nanowire solution, the concentration of the silver metal nanowire solution is 10mg/mL to 60mg/mL, the rotating speed of the spin coating is 1000-4000r/min, and the time of the spin coating is 10-50 seconds.

According to the structure of the quantum dot light-emitting device and the preparation process, the quantum dot light-emitting device provided by the embodiment of the invention can be prepared by forming the first electrode by adopting the water dispersion material and performing spin coating, the process is simple, and the cost is saved. Meanwhile, the quantum dot light-emitting layer is protected from water through the waterproof layer, and damage to the quantum dot light-emitting layer caused by liquid in the process of preparing the water-dispersible first electrode is avoided.

The preparation process of the quantum dot light-emitting device provided by the embodiment of the invention can be realized by utilizing the existing mature preparation equipment, has small improvement on the existing process, can be well compatible with the existing preparation process, has the advantages of simple process realization, high production efficiency, low production cost, high yield and the like, and has good application prospect.

On the basis of the technical concept of the display substrate, the embodiment of the invention also provides a preparation method of the quantum dot light-emitting device, which comprises the following steps:

forming a second electrode;

forming a quantum dot light emitting layer over the second electrode;

forming a waterproof layer on the quantum dot light emitting layer;

The detailed preparation process of the preparation method of the display substrate according to the embodiment of the present invention has been described in detail in the foregoing embodiments, and is not repeated herein.

The embodiment of the invention also provides a display device which comprises the display substrate of the embodiment. The display device can be any product or component with a display function, such as a mobile phone, a tablet computer, a television, a display, a notebook computer, a digital photo frame, a navigator and the like, and can also be a product or component with VR, AR and 3D display functions.

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

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

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

Claims

1. A quantum dot light-emitting device comprises a first electrode, a second electrode and a quantum dot light-emitting layer, wherein the first electrode and the second electrode are arranged oppositely, the quantum dot light-emitting layer is arranged between the first electrode and the second electrode, the quantum dot light-emitting device is characterized in that the first electrode adopts a water dispersion material, and a waterproof layer is formed between the first electrode and the quantum dot light-emitting layer.

2. The quantum dot light-emitting device according to claim 1, wherein the material of the water barrier layer is metal oxide.

3. The qd-led device of claim 2, wherein the metal oxide is one or more of tin metal oxide, molybdenum metal oxide, tungsten metal oxide and nickel metal oxide.

4. The quantum dot light-emitting device according to claim 1, wherein the compactness of the water-proof layer is greater than 99%.

5. The quantum dot light-emitting device according to claim 1, wherein the water-repellent layer has a thickness of 5nm to 30 nm.

6. The quantum dot light-emitting device according to claim 1, wherein an electron transport layer is disposed between the quantum dot light-emitting layer and the water-repellent layer, and the water-repellent layer is formed on the electron transport layer.

7. The quantum dot light-emitting device according to claim 6, wherein the electron transport layer is made of one or more of azo compound nanoparticles, zinc oxide magnesium alloy nanoparticles, zinc oxide nanoparticles, and zinc oxide aluminum alloy nanoparticles.

8. The quantum dot light-emitting device according to claim 1, wherein the aqueous dispersion material is a metal nanowire.

9. A display device comprising the quantum dot light-emitting device according to any one of claims 1 to 8.

10. A method for manufacturing a quantum dot light-emitting device, comprising:

forming a second electrode;

forming a quantum dot light emitting layer over the second electrode;

forming a waterproof layer on the quantum dot light emitting layer;