WO2022143569A1

WO2022143569A1 - Quantum dot light-emitting diode and preparation method therefor

Info

Publication number: WO2022143569A1
Application number: PCT/CN2021/141801
Authority: WO
Inventors: 王劲; 周礼宽; 杨一行; 曹蔚然
Original assignee: Tcl科技集团股份有限公司
Priority date: 2020-12-31
Filing date: 2021-12-27
Publication date: 2022-07-07
Also published as: CN114695735A

Abstract

Disclosed in the present application are a quantum dot light-emitting diode and a preparation method therefor. The quantum dot light-emitting diode comprises an anode and a cathode provided opposite to each other, a quantum dot light-emitting layer provided between the anode and the cathode, and an electronic functional layer provided between the quantum dot light-emitting layer and the cathode. The quantum dot light-emitting layer comprises an active material selected from at least one of organic hydrocarbon having at least one hydrogen atom substituted by a carboxyl group, an organic ester comprising a carbon-carbon double bond or a carbon-carbon triple bond or a benzene ring, and an unsaturated ketone. By introducing the active material to the quantum dot light-emitting layer, the present application improves a positive aging effect of the quantum dot light-emitting diode.

Description

Quantum dot light-emitting diode and preparation method thereof

This application claims the priority of the Chinese patent application with the application number 202011639233.8 and the invention titled "Quantum Dot Light Emitting Diode and its Preparation Method" filed in the China Patent Office on December 31, 2020, the entire contents of which are incorporated by reference in in this application.

technical field

The present application relates to the field of display technology, and in particular, to a quantum dot light-emitting diode and a preparation method thereof.

Background technique

Quantum Dot Light Emitting Diode Light Emitting Diodes, QLED) is an electroluminescent device based on quantum dots (QDs) technology, with self-luminescence, no backlight module, wide viewing angle, high contrast, full curing, suitable for flexible panels, temperature characteristics A series of excellent features, such as good performance, fast response speed, energy saving and environmental protection, have become the research hotspot and key development direction of new display technology.

Although QLED devices borrow and utilize organic light-emitting diodes (Organic Light-Emitting Diodes) Diode, OLED) device structure, but due to the difference in material composition, the aging phenomenon and aging mechanism of the two are very different. For example, QLED devices have various efficiencies (current, power or external quantum efficiency) that decay or increase over time, that is, "negative aging effect" or "positive aging effect". At present, the mechanism of the aging effect is still unclear. Many studies have concluded that the changes in device efficiency are mainly caused by factors such as the degradation of the hole functional layer, the accumulation of interface charges, the suppression of surface defect states in the electronic functional layer, or the change of charge mobility. In addition, the difference in the matching between the materials of different light-emitting color quantum dots and other functional layer materials will also cause different device aging mechanisms. For example, the aging effect of red QLED devices is more caused by the degradation of the organic hole functional layer, while blue QLED devices The aging effect is more due to the mismatch between the conduction-band maximum (CBM) of the quantum dot light-emitting layer and the electronic functional layer, which leads to the accumulation of electrons in the electronic functional layer.

Some researchers have proposed a method and structure for improving the positive aging effect and stability of quantum dot diodes, which revealed that the curable resin-encapsulated QLED device containing active materials such as saturated/unsaturated carboxylic acids has a significant positive aging effect. , and the heat treatment of the packaged device can further improve the efficiency and accelerate the forward aging process (the positive aging effect is generally completed in about 4 to 8 days, and the efficiency tends to be stable). This technology is achieved by incorporating active materials into a curable encapsulation resin, or by exposing the QLED device to an environment containing the active material, or by cleaning the QLED stack with a solution containing the active material to introduce the active material into the QLED device. This technology has the most significant positive aging effect on green QLED devices, and the efficiency can be improved by 175% (the efficiency improvement ratio is the percentage of the difference between the maximum device efficiency and the first-day test efficiency and the first-day test efficiency ratio), but blue and red The positive aging effect of QLED devices is small, and the maximum efficiency is only increased by 20%.

technical problem

One of the objectives of the embodiments of the present application is to provide a quantum dot light-emitting diode and a method for preparing the same.

technical solutions

The technical scheme adopted in the embodiment of the present application is:

In a first aspect, a quantum dot light-emitting diode is provided, comprising an anode and a cathode disposed opposite to each other, a quantum dot light-emitting layer disposed between the anode and the cathode, and a quantum dot light-emitting layer disposed between the quantum dot light-emitting layer and the cathode. The electronic functional layer between the cathodes; wherein, the quantum dot light-emitting layer contains active materials, and the active materials are selected from organic hydrocarbons with at least one hydrogen atom substituted by carboxyl groups, carbon-carbon double bonds or carbon-carbon triple bonds, or benzene At least one of cyclic organic esters and unsaturated ketones.

In some embodiments, the active material is selected from the group consisting of acrylic acid, benzoic acid, methacrylic acid, 3-butenoic acid, crotonic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, hydroxyethyl methacrylate, methyl methacrylate At least one of methyl methacrylate, butyl acrylate, trimethylol glycerate and N-vinylpyrrolidone.

In some embodiments, the active material accounts for 0.0001% to 1% of the total weight of the quantum dot light-emitting layer.

In some embodiments, the quantum dot light-emitting layer consists of quantum dots and the active material.

In some embodiments, the quantum dots are selected from the group consisting of II-VI compounds, III-V compounds, II-V compounds, III-VI compounds, IV-VI compounds, I-III-VI compounds, One or more of II-IV-VI compounds or IV elements.

In some embodiments, the quantum dots are one or more of CdSe/ZnSe, CdSe/CdS, CdSe/CdS/ZnS, ZnCdSeS, ZnCdSeS/ZnS, ZnCdS/ZnS, ZnSe/ZnS.

In some embodiments, the quantum dot light emitting diode further includes a hole functional layer disposed between the anode and the quantum dot light emitting layer.

In a second aspect, two preparation methods of quantum dot light-emitting diodes are provided.

The first method for preparing a quantum dot light-emitting diode comprises the following steps:

Provide a prefabricated device for preparing a quantum dot light-emitting layer;

The prefabricated device is placed in an atmosphere containing a gaseous active material, and a quantum dot light-emitting layer is prepared on the prefabricated device; wherein the gaseous active material is selected from organic hydrocarbons whose at least one hydrogen atom is substituted by a carboxyl group, a carbon-containing At least one of carbon double bond or carbon-carbon triple bond or organic ester of benzene ring and unsaturated ketone.

In some embodiments, the atmospheric environment is a mixed gaseous environment formed by the gaseous active material and at least one of oxygen, nitrogen, argon, and carbon dioxide.

In some embodiments, the gaseous active material accounts for 0.1% to 50% of the total volume of gas in the atmosphere.

In some embodiments, the temperature of the gaseous environment is 25-150° C., and the total pressure is -0.1-4 MPa.

The preparation method of the second quantum dot light-emitting diode comprises the following steps:

A mixed solution of quantum dots and active materials is configured, wherein the active materials are selected from organic hydrocarbons with at least one hydrogen atom substituted by carboxyl groups, organic esters containing carbon-carbon double bonds or carbon-carbon triple bonds or benzene rings, and unsaturated ketones at least one of;

A prefabricated device on which a quantum dot light-emitting layer is to be prepared is provided, and the mixed solution is deposited on the prefabricated device to prepare a quantum dot light-emitting layer.

In some embodiments, in the mixed solution, the active material accounts for 0.0001% to 1% of the total weight of the quantum dots and the active material.

In some embodiments, after the step of depositing the mixed solution on the prefabricated device, the method further includes: drying at a temperature not higher than 150° C. to prepare the quantum dot light-emitting layer.

beneficial effect

The beneficial effect of the quantum dot light-emitting diode provided by the embodiments of the present application is that the quantum dot light-emitting layer contains an active material, and the active material is selected from organic hydrocarbons in which at least one hydrogen atom is substituted by a carboxyl group, a carbon-carbon double bond or a carbon-carbon triple bond. Or at least one of organic esters of benzene rings and unsaturated ketones. The carboxylic acid, delocalized π bond and/or H ⁺ contained in the active material can passivate the quantum dot material and the adjacent electronic functional material thin film by means of coordination and/or H ⁺ reaction etc. The cluster-distributed defect states can effectively suppress the quenching of surface excitons and increase the probability of exciton radiation recombination. At the same time, after the active material is introduced into the interface of the electronic functional layer adjacent to the quantum dot light-emitting layer through interface contact or infiltration, it contains carboxylic acid. , delocalized π bonds and/or H ⁺ play a role in modifying the interface of the electronic functional layer/quantum dot light-emitting layer, regulating the electron injection barrier between the quantum dot light-emitting layer and the electronic functional layer, and blocking or promoting electron injection, which is beneficial to Charge injection balance. The blue and red quantum dot light-emitting diodes thus provided have the highest forward aging effect efficiencies of 87.6% and 117%, respectively, after 6 days, which significantly improves the positive aging effect of the device.

The beneficial effect of the method for preparing a quantum dot light-emitting diode provided by the embodiments of the present application is that the quantum dot light-emitting diode is obtained by introducing an active material into the quantum dot light-emitting layer by a gas phase method or a mild solution processing method. The active material can modify/passivate the quantum dots and the interface surface defects of the electronic functional layer adjacent to the quantum dot light-emitting layer, suppress the quenching of surface excitons, reduce the charge accumulation of the electronic functional layer, increase the exciton radiation recombination probability, and The electron injection potential barrier between the quantum dot light-emitting layer and the electronic functional layer can block or promote electron injection, which is beneficial to the balance of charge injection, thereby significantly improving the positive aging effect of the device. In addition, the gas phase method or the solution processing method has simple process technology and low equipment requirements, which can effectively reduce the preparation cost.

Description of drawings

In order to illustrate the technical solutions in the embodiments of the present application more clearly, the following briefly introduces the accompanying drawings that are used in the description of the embodiments or exemplary technologies. Obviously, the drawings in the following description are only for the present application. In some embodiments, for those of ordinary skill in the art, other drawings can also be obtained according to these drawings without any creative effort.

1 is a schematic structural diagram of a quantum dot light-emitting diode provided by an embodiment of the present application;

2 is a schematic structural diagram of a quantum dot light-emitting diode containing a hole function provided by an embodiment of the present application;

3 is a schematic structural diagram of a positive structure quantum dot light-emitting diode provided by an embodiment of the present application;

FIG. 4 is a schematic structural diagram of another positive structure quantum dot light-emitting diode provided by an embodiment of the present application;

5 is a schematic structural diagram of a quantum dot light-emitting diode with an inversion structure provided by an embodiment of the present application;

6 is a schematic structural diagram of another inversion structure quantum dot light-emitting diode provided by an embodiment of the present application;

FIG. 7 is a flow chart of the first preparation process of the quantum dot light-emitting diode provided by the embodiment of the present application;

FIG. 8 is a flow chart of the second preparation process of the quantum dot light-emitting diode provided by the embodiment of the present application;

FIG. 9 is a schematic structural diagram of the quantum dot light-emitting diode provided in Embodiment 1 of the present application.

Embodiments of the present invention

In order to make the purpose, technical solutions and advantages of the present application more clearly understood, the present application will be described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application, but not to limit the present application.

In the claims and specific embodiments of the present application, the term "and/or" describes the association relationship of associated objects, indicating that there can be three kinds of relationships. For example, A and/or B can represent three cases where A exists alone, A and B exist simultaneously, and B exists alone. where A and B can be singular or plural. The character "/" generally indicates that the associated objects are an "or" relationship.

In this application, "at least one" means one or more, and "plurality" means two or more. "At least one item(s) below" or similar expressions refer to any combination of these items, including any combination of single item(s) or plural items(s). For example, "at least one (one) of a, b, or c", or "at least one (one) of a, b, and c", can mean: a, b, c, a-b ( That is, a and b), a-c, b-c, or a-b-c, where a, b, and c can be single or multiple respectively.

It should be understood that, in various embodiments of the present application, the size of the sequence numbers of the above-mentioned processes does not imply the sequence of execution, some or all of the steps may be executed in parallel or sequentially, and the execution sequence of each process should be based on its functions and It is determined by the internal logic and should not constitute any limitation on the implementation process of the embodiments of the present application.

The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. As used in the embodiments of this application and the appended claims, the singular forms "a," "the," and "the" are intended to include the plural forms as well, unless the context clearly dictates otherwise.

When encapsulating devices with active materials such as saturated/unsaturated carboxylic acids, the positive aging effect of blue and red QLED devices is not obvious. Thin-film devices processed by low-temperature solution methods are accompanied by common crystal defects (such as point defects), which can induce electronic states deep in the band gap of the relevant functional layers, trap charge carriers, and affect device performance.

In view of this, as shown in FIG. 1 , a first aspect of the embodiment of the present application provides a quantum dot light-emitting diode, comprising an anode 10 and a cathode 50 arranged opposite to each other, and a quantum dot light-emitting layer 30 arranged between the anode 10 and the cathode 50 , and the electronic functional layer 40 arranged between the quantum dot light-emitting layer and the cathode; wherein, the quantum dot light-emitting layer 30 contains active materials, and the active materials are selected from organic hydrocarbons with at least one hydrogen atom substituted by carboxyl groups, and carbon-carbon double bonds. Or at least one of carbon-carbon triple bond or organic ester of benzene ring and unsaturated ketone.

In the quantum dot light-emitting diode provided in the embodiment of the present application, the quantum dot light-emitting layer 30 contains an active material, and the active material is selected from organic hydrocarbons with at least one hydrogen atom substituted by a carboxyl group, a carbon-carbon double bond or a carbon-carbon triple bond, or a benzene ring. At least one of organic esters and unsaturated ketones. The carboxylic acid, delocalized π bond and/or H ⁺ contained in the active material passivate the quantum dot material and the adjacent electronic functional material film by means of coordination and/or H ⁺ reaction, showing discrete, nano-scale cluster distribution on the thin film The defect state can effectively suppress the quenching of surface excitons and increase the probability of exciton radiation recombination; at the same time, after the active material is introduced into the interface of the electronic functional layer adjacent to the quantum dot light-emitting layer through interface contact or infiltration, it contains carboxylic acid, ionic The domain π bond and/or H ⁺ play a role in modifying the interface of the electronic functional layer/quantum dot light-emitting layer, regulating the electron injection barrier between the quantum dot light-emitting layer and the electronic functional layer, blocking or promoting electron injection, which is beneficial to charge injection balance. Compared with the current positive aging effect efficiency of blue and red QLED devices, the efficiency of the positive aging effect is increased by up to 20%. The positive aging effect of the device is significantly improved.

In the quantum dot light-emitting device, the quantum dot light-emitting layer 30 is a functional layer that generates light, and at least includes a light-emitting material—quantum dots. In the embodiment of the present application, in addition to quantum dots, the quantum dot light-emitting layer 30 also contains an active material for improving the positive aging effect. In some embodiments, the quantum dot light-emitting layer 30 consists of quantum dots and the active material.

In the embodiments of the present application, the active material is selected from at least one of organic hydrocarbons with at least one hydrogen atom substituted by carboxyl groups, organic esters containing carbon-carbon double bonds or carbon-carbon triple bonds or benzene rings, and unsaturated ketones. Specifically, organic hydrocarbons in which at least one hydrogen atom is substituted by a carboxyl group refers to saturated/or unsaturated organic carboxylic acids, and the organic carboxylic acids do not contain carboxylic acids, carbon-carbon double bonds, carbon-carbon triple bonds, and aromatic rings. other reactive functional groups.

In some embodiments, organic hydrocarbons having at least one hydrogen atom replaced by a carboxyl group include: acetic acid, propionic acid, butyric acid, isobutyric acid, acrylic acid, benzoic acid, methacrylic acid, 3-butenoic acid, crotonic acid, but not Limited to this; organic esters containing carbon-carbon double bonds or carbon-carbon triple bonds or benzene rings include: hydroxyethyl methacrylate, methyl methacrylate, butyl acrylate, trimethylol acrylate, but not limited thereto; unsaturated ketones include, but are not limited to, N-vinylpyrrolidone.

In some embodiments, the active material is selected from the group consisting of acrylic acid, benzoic acid, methacrylic acid, 3-butenoic acid, crotonic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, hydroxyethyl methacrylate, methacrylic acid At least one of methyl ester, butyl acrylate, trimethylol glycerate and N-vinylpyrrolidone. Since these active materials have carboxylic acids, delocalized π bonds and/or H ⁺ , passivated quantum dot materials and adjacent electronic functional material films exhibit discrete, nano-scale cluster distributions through coordination and/or H ⁺ reactions, etc. It can effectively suppress the quenching of surface excitons and increase the probability of exciton radiation recombination; at the same time, after the active material is introduced into the interface of the electronic functional layer 40 adjacent to the quantum dot light-emitting layer 30 through interface contact or infiltration, it contains carboxylic acid. , delocalized π bonds and/or H ⁺ play a role in modifying the interface of the electronic functional layer 40/quantum dot light-emitting layer 30, regulating the electron injection barrier between the quantum dot light-emitting layer 30 and the electronic functional layer 40, and realizing blocking or promoting electrons injection, which is beneficial to the balance of charge injection, thereby significantly improving the positive aging effect of the device.

In some embodiments, the active material accounts for 0.0001% to 1% of the total weight of the quantum dot light-emitting layer 30 . The carboxyl group, H ⁺ and other substances contained in the active material will cause the quenching of quantum dot light emission to a certain extent, but when the content of the active material in the quantum dot light-emitting layer 30 is within the above range, the active material can significantly improve the quantum dot light-emitting diode. It is the positive aging effect of blue quantum dot light-emitting diodes and red quantum dot light-emitting diodes, and the luminescence effect of quantum dots is controlled in a small range, so that the luminous efficiency can still be stronger than that of quantum dot light-emitting diodes without active materials. In some embodiments, the active material may account for 0.0001%, 0.0005%, 0.001%, 0.005%, 0.01%, 0.05%, 0.1%, 0.5%, 1% of the total weight of the quantum dot light-emitting layer.

In some embodiments, as shown in FIG. 2 , the quantum dot light emitting diode further includes a hole functional layer 20 disposed between the anode 10 and the quantum dot light emitting layer 30 . The hole functional layer 20 includes at least one of a hole transport layer, a hole injection layer, and an electron blocking layer.

In this embodiment of the present application, the quantum dot light-emitting diode may further include a substrate, and the anode 10 or the cathode 50 is disposed on the substrate.

The quantum dot light emitting diodes provided in the embodiments of the present application are classified into positive structure quantum dot light emitting diodes and inverse structure quantum dot light emitting diodes.

In one embodiment, as shown in FIG. 3 , the positive-type quantum dot light-emitting diode includes an anode 10 and a cathode 50 disposed opposite to each other, a quantum dot light-emitting layer 30 disposed between the anode 10 and the cathode 50, and a cathode disposed on the cathode. An electron functional layer 40 such as an electron transport layer and an electron injection layer between the quantum dot light-emitting layer 30 and the quantum dot light-emitting layer 30 , and the anode 10 is arranged on the substrate 100 . Further, a hole functional layer 20 such as a hole transport layer, a hole injection layer, and an electron blocking layer can be provided between the anode 10 and the quantum dot light-emitting layer 30 . In some positive structure quantum dot light emitting diode embodiments, as shown in FIG. 4 , the quantum dot light emitting diode includes a substrate 100 , an anode 10 disposed on the surface of the substrate 100 , and a hole injection layer 21 disposed on the surface of the anode 10 . , the hole transport layer 22 arranged on the surface of the hole injection layer 21, the quantum dot light-emitting layer 30 arranged on the surface of the hole transport layer 22, the electron transport layer 41 arranged on the surface of the quantum dot light-emitting layer 30, and the electron transport layer 41 arranged on the surface of the electron transport layer 22. Cathode 50 on the surface of 41.

In one embodiment, as shown in FIG. 5 , the quantum dot light-emitting diode of the inversion structure includes a stacked structure of an anode 10 and a cathode 50 arranged oppositely, and a quantum dot light-emitting layer 30 arranged between the anode 10 and the cathode 50, and an electron injection layer 40 such as an electron transport layer and an electron injection layer disposed between the cathode 50 and the quantum dot light-emitting layer 30 , and the cathode is disposed on the substrate 100 . Further, a hole functional layer 20 such as a hole transport layer, a hole injection layer, and an electron blocking layer can be provided between the anode 10 and the quantum dot light-emitting layer 30 . In some embodiments of quantum dot light emitting diodes with inversion structure, as shown in FIG. 6 , the quantum dot light emitting diodes include a substrate 100 , a cathode 50 disposed on the surface of the substrate 100 , an electron transport layer 41 disposed on the surface of the cathode 50 , The quantum dot light-emitting layer 30 provided on the surface of the electron transport layer 41, the hole transport layer 22 provided on the surface of the quantum dot light-emitting layer 30, the hole injection layer 21 provided on the surface of the hole transport layer 22, and the hole injection layer 21 Anode 10 on the surface.

In the above-mentioned embodiment, the substrate 100 may include a rigid substrate such as glass, metal foil, etc. commonly used rigid substrates, or a flexible substrate such as polyimide (PI), polycarbonate (PC), polystyrene ( PS), polyethylene (PE), polyvinyl chloride (PV), polyvinylpyrrolidone (PVP), polyethylene terephthalate (PET) and other similar materials, which mainly play a supporting role.

The anode 10 may adopt common anode materials and thicknesses, which are not limited in the embodiments of the present application. For example, the anode material can be indium tin oxide (ITO), indium zinc oxide (IZO) conductive glass or indium tin oxide, indium zinc oxide electrodes, or other metal materials such as gold, silver, aluminum, and the like. In some embodiments, anode 10 is an ITO electrode. In this case, the hole injection layer including the two-dimensional black phosphorus material and the metal compound has a high work function and is highly matched to the anode 10; and can exert excellent carrier mobility, which can replace PEDOT:PSS, but Will not cause damage to the anode.

In the embodiments of the present application, the quantum dots are group II-VI semiconductor nanocrystals, group III-V semiconductor nanocrystals, group II-V semiconductor nanocrystals, group III-VI semiconductor nanocrystals, group IV-VI semiconductor nanocrystals, - one of group III-VI semiconductor nanocrystals, group I-III-VI core-shell quantum dots, group II-IV-VI semiconductor nanocrystals, group II-IV-VI core-shell structure quantum dots or group IV elements or more. The quantum dots can be red light quantum dots, correspondingly, the quantum dot light emitting diodes are red light quantum dot light emitting diodes; the quantum dots can be blue light quantum dots, correspondingly, the quantum dot light emitting diodes are blue light quantum dot light emitting diodes; the quantum dots can be green light quantum dots dot, correspondingly, the quantum dot light-emitting diode is a green light quantum dot light-emitting diode. In some embodiments, the quantum dots are one or more of CdSe/ZnSe, CdSe/CdS, CdSe/CdS/ZnS, ZnCdSeS, ZnCdSeS/ZnS, ZnCdS/ZnS, ZnSe/ZnS.

In the embodiment of the present application, the electronic functional layer 40 includes at least one of an electron transport layer and an electron injection layer. The material of the electronic functional layer 40 is selected from inorganic materials with electron transport capability, especially inorganic nanoparticle materials, including one or more of doped or undoped metal oxides. In some embodiments, the material of the electronic functional layer 40 is selected from one or more of ZnO, TiO ₂ , SnO ₂ , Ta ₂ O ₃ , ZrO ₂ , NiO, TiLiO, ZnAlO, ZnMgO, ZnSnO, ZnLiO, and InSnO .

In the embodiments of the present application, the cathode 50 may adopt common cathode materials, including but not limited to one or more of metal materials, carbon materials, and metal oxides. Wherein, the metal material includes one or more of Al, Ag, Cu, Mo, Au, Ba, Ca, and Mg; the carbon material includes one or more of graphite, carbon nanotube, graphene, and carbon fiber; The oxides may be doped or undoped metal oxides including one or more of ITO, FTO, ATO, AZO, GZO, IZO, MZO, AMO.

When the quantum dot light emitting diode is a blue quantum dot light emitting diode or a red light quantum dot light emitting diode, after the active material is introduced into the quantum dot light emitting layer, the positive aging effect of the device is more significant.

The quantum dot light-emitting diode provided by the present application can be prepared by the following method.

In a second aspect, the embodiments of the present application provide two methods for fabricating quantum dot light-emitting diodes.

As shown in Figure 7, the first method for preparing a quantum dot light-emitting diode includes the following steps:

S01. Provide a prefabricated device for the quantum dot light-emitting layer to be prepared;

S02. The prefabricated device is placed in an atmosphere containing a gaseous active material, and a quantum dot light-emitting layer is prepared on the prefabricated device; wherein, the gaseous active material is selected from organic hydrocarbons with at least one hydrogen atom substituted by a carboxyl group, a carbon-carbon double bond or At least one of carbon-carbon triple bond or organic ester of benzene ring and unsaturated ketone.

In the above step S01, a prefabricated device for preparing a quantum dot light-emitting layer is provided. In one embodiment, the prefabricated substrate includes at least an anode substrate. In some embodiments, the prefabricated device includes an anode substrate, a hole functional layer bonded to the anode surface of the anode substrate. In another embodiment, the prefabricated substrate includes at least a cathode substrate. In some embodiments, the prefabricated device includes a cathode substrate, an electronic functional layer bonded to the cathode surface of the cathode substrate. The selection of the hole functional layer and the electron functional layer is as described above, and will not be repeated here.

In the above step S02, the prefabricated device is placed in an atmosphere containing a gaseous active material, so that the prefabricated device prepares a quantum dot light-emitting layer in an environment containing a gaseous active material, thereby introducing an active material into the quantum dot light-emitting layer. Wherein, the atmosphere environment containing gaseous active material can be pure gaseous active material atmosphere; it can also be inert atmosphere environment containing gaseous active material, wherein, inert atmosphere includes nitrogen atmosphere, carbon dioxide atmosphere or argon atmosphere and the like. The atmospheric environment is a mixed gaseous environment formed by the gaseous active material and at least one of oxygen, nitrogen, argon, and carbon dioxide.

In some embodiments, the gaseous active material accounts for 0.1% to 50% of the total volume of gas in the atmosphere. In some embodiments, the temperature of the gaseous environment is 25-150° C. and the total pressure is -0.1-4 MPa.

Among them, the gaseous active material is the vapor of the active material. Specifically, the gaseous active material is selected from at least one of organic hydrocarbons with at least one hydrogen atom substituted by carboxyl groups, organic esters containing carbon-carbon double bonds or carbon-carbon triple bonds or benzene rings, and unsaturated ketones.

In some embodiments, the active material is selected from the group consisting of acrylic acid, benzoic acid, methacrylic acid, 3-butenoic acid, crotonic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, hydroxyethyl methacrylate, methacrylic acid At least one of methyl ester, butyl acrylate, trimethylol glycerate and N-vinylpyrrolidone.

To prepare a quantum dot light-emitting layer on a prefabricated device, except that the preparation environment is limited by an atmosphere containing gaseous active materials, the process of preparing the quantum dot light-emitting layer is carried out with reference to the conventional process. In some embodiments, the quantum dot light-emitting layer is prepared by solution processing on a prefabricated device.

In some embodiments, the prefabricated substrate is an anode substrate; in the step of preparing the quantum dot light-emitting layer on the prefabricated device, the quantum dot light-emitting layer is prepared on the anode surface of the anode substrate. Further, the method for preparing a quantum dot light-emitting diode further includes: preparing an electronic functional layer on the surface of the quantum dot light-emitting layer away from the anode, and preparing a cathode on the surface of the electronic functional layer away from the quantum dot light-emitting layer.

In some embodiments, the prefabricated device includes an anode substrate and a hole functional layer bound on the anode surface of the anode substrate; in the step of preparing the quantum dot light-emitting layer on the prefabricated device, the quantum dots are prepared on the surface of the hole functional layer facing away from the anode light-emitting layer. Further, the method for preparing a quantum dot light-emitting diode further includes: preparing an electronic functional layer on the surface of the quantum dot light-emitting layer away from the anode, and preparing a cathode on the surface of the electronic functional layer away from the quantum dot light-emitting layer.

In some embodiments, the prefabricated substrate is a cathode substrate; in the step of preparing the quantum dot light-emitting layer on the prefabricated device, the quantum dot light-emitting layer is prepared on the cathode surface of the cathode substrate. Further, the method for preparing a quantum dot light-emitting diode further includes: preparing an anode on the surface of the quantum dot light-emitting layer facing away from the cathode. In some embodiments, before preparing the anode, a hole functional layer is prepared on the surface of the quantum dot light emitting layer facing away from the cathode, and an anode is prepared on the surface of the hole functional layer facing away from the quantum dot light emitting layer.

In some embodiments, the prefabricated device includes a cathode substrate and an electronic functional layer combined on the cathode surface of the cathode substrate; in the step of preparing the quantum dot light-emitting layer on the prefabricated device, the quantum dot light-emitting layer is prepared on the surface of the electronic functional layer facing away from the cathode . Further, the method for preparing a quantum dot light-emitting diode further includes: preparing an anode on the surface of the quantum dot light-emitting layer facing away from the cathode. In some embodiments, before preparing the anode, a hole functional layer is prepared on the surface of the quantum dot light emitting layer facing away from the cathode, and an anode is prepared on the surface of the hole functional layer facing away from the quantum dot light emitting layer.

As shown in Figure 8, the second method for preparing a quantum dot light-emitting diode includes the following steps:

E01. Configure the mixed solution of quantum dots and active material, wherein the active material is selected from organic hydrocarbons with at least one hydrogen atom substituted by carboxyl groups, organic esters containing carbon-carbon double bonds or carbon-carbon triple bonds or benzene rings, unsaturated ketones at least one of;

E02. Provide a prefabricated device for preparing a quantum dot light-emitting layer, deposit a mixed solution on the prefabricated device, and prepare a quantum dot light-emitting layer.

In the above-mentioned step E01, to configure a mixed solution of quantum dots and active materials, a solution containing quantum dots may be configured first, then an active material is added, and mixed to form a mixed solution; or a solution containing sexual components may be configured first, and then quantum dots are added to mix A mixed solution is formed; the quantum dots and the active material can also be added simultaneously or successively in the solvent, and mixed to form a mixed solution, and the order of the quantum dots and the active material is not required.

In some embodiments, the quantum dots are selected from the group consisting of II-VI compounds, III-V compounds, II-V compounds, III-VI compounds, IV-VI compounds, I-III-VI compounds, II- One or more of group IV-VI compounds or group IV elements, exemplarily, the quantum dots are CdSe/ZnSe, CdSe/CdS, CdSe/CdS/ZnS, ZnCdSeS, ZnCdSeS/ZnS, ZnCdS/ZnS, One or more of ZnSe/ZnS.

Wherein, the active material is selected from at least one of organic hydrocarbons with at least one hydrogen atom substituted by carboxyl groups, organic esters containing carbon-carbon double bonds or carbon-carbon triple bonds or benzene rings, and unsaturated ketones. In some embodiments, the active material is selected from the group consisting of acrylic acid, benzoic acid, methacrylic acid, 3-butenoic acid, crotonic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, hydroxyethyl methacrylate, methacrylic acid At least one of methyl ester, butyl acrylate, trimethylol glycerate and N-vinylpyrrolidone. In the mixed solution, in the active material, the total weight of the quantum dots and the active material is 0.0001% to 1%.

In some embodiments, in the mixed solution of the quantum dots and the active material, the active material accounts for 0.0001% to 1% of the total weight of the quantum dots and the active material. Since the above-mentioned active materials have a certain degree of quenching effect on the luminescence efficiency of the quantum dot solution, in this case, the content of the active material is relatively small relative to the content of the quantum dots, which can avoid obvious quenching of the luminescence of the quantum dots; however, , can play the role of improving the positive aging effect after introducing the quantum dot light-emitting layer through the subsequent steps.

In the above step E02, a prefabricated device for preparing the quantum dot light-emitting layer is provided. In one embodiment, the prefabricated substrate includes at least an anode substrate. In some embodiments, the prefabricated device includes an anode substrate, a hole functional layer bonded to the anode surface of the anode substrate. In another embodiment, the prefabricated substrate includes at least a cathode substrate. In some embodiments, the prefabricated device includes a cathode substrate, an electronic functional layer bonded to the cathode surface of the cathode substrate. The selection of the hole functional layer and the electron functional layer is as described above, and will not be repeated here.

The deposition of the mixed solution on the prefabricated device can be achieved by a conventional method, and after drying, the quantum dot light-emitting layer is prepared. In some embodiments, after the step of depositing the mixed solution on the prefabricated device, the method further includes: drying at a temperature not higher than 150° C. to prepare a quantum dot light-emitting layer, so as to avoid excessive temperature and cause the active material to volatilize , affecting the positive aging effect of quantum dot light-emitting diodes.

In some embodiments, the prefabricated substrate is an anode substrate; in the step of depositing a mixed solution on the prefabricated device to prepare a quantum dot light-emitting layer, the mixed solution is deposited on the anode surface of the anode substrate to prepare a quantum dot light-emitting layer. Further, the method for preparing a quantum dot light-emitting diode further includes: preparing an electronic functional layer on the surface of the quantum dot light-emitting layer away from the anode, and preparing a cathode on the surface of the electronic functional layer away from the quantum dot light-emitting layer.

In some embodiments, the prefabricated device includes an anode substrate, and a hole functional layer combined on the anode surface of the anode substrate; in the step of depositing a mixed solution on the prefabricated device to prepare a quantum dot light-emitting layer, the hole functional layer is away from the anode in the step of depositing a mixed solution on the prefabricated device. The mixed solution is deposited on the surface to prepare a quantum dot light-emitting layer. Further, the method for preparing a quantum dot light-emitting diode further includes: preparing an electronic functional layer on the surface of the quantum dot light-emitting layer away from the anode, and preparing a cathode on the surface of the electronic functional layer away from the quantum dot light-emitting layer.

In some embodiments, the prefabricated substrate is a cathode substrate; in the step of depositing a mixed solution on the prefabricated device to prepare a quantum dot light-emitting layer, the mixed solution is deposited on the cathode surface of the cathode substrate to prepare a quantum dot light-emitting layer. Further, the method for preparing a quantum dot light-emitting diode further includes: preparing an anode on the surface of the quantum dot light-emitting layer facing away from the cathode. In some embodiments, before preparing the anode, a hole functional layer is prepared on the surface of the quantum dot light emitting layer facing away from the cathode, and an anode is prepared on the surface of the hole functional layer facing away from the quantum dot light emitting layer.

In some embodiments, the prefabricated device includes a cathode substrate, and an electronic functional layer combined on the cathode surface of the cathode substrate; in the step of depositing a mixed solution on the prefabricated device to prepare a quantum dot light-emitting layer, the electronic functional layer is prepared on the surface away from the cathode. Quantum dot light-emitting layer. Further, the method for preparing a quantum dot light-emitting diode further includes: preparing an anode on the surface of the quantum dot light-emitting layer facing away from the cathode. In some embodiments, before preparing the anode, a hole functional layer is prepared on the surface of the quantum dot light emitting layer facing away from the cathode, and an anode is prepared on the surface of the hole functional layer facing away from the quantum dot light emitting layer.

In the preparation method of quantum dot light-emitting diode provided in the embodiment of the present application, the quantum dot light-emitting diode is obtained by introducing active material into the quantum dot light-emitting layer by gas phase method or mild solution processing method. The active material can modify/passivate the quantum dots and the surface defects of the electronic functional layer adjacent to the quantum dot light-emitting layer, suppress the quenching of surface excitons, reduce the charge accumulation of the electronic functional layer, increase the exciton radiation recombination probability, and reduce the quantum dots. The electron injection potential barrier between the light-emitting layer and the electronic functional layer can block or promote electron injection, which is beneficial to the balance of charge injection, thereby significantly improving the positive aging effect of the device. In addition, the gas phase method or the solution processing method has simple process technology and low equipment requirements, which can effectively reduce the preparation cost.

The following description will be given in conjunction with specific embodiments.

Example 1

As shown in FIG. 9, a red quantum dot light-emitting diode, a substrate 100, an anode 110 located on the substrate 100, and a hole functional layer 120, a quantum dot light-emitting layer 130, an electron functional layer 140 and a cathode are sequentially stacked 150, wherein the material of the substrate 100 is silicon glass, the material of the anode 110 is ITO, the material of the hole function layer 120 is TFB, the material of the quantum dot light-emitting layer 130 includes quantum dots CdZnSe/ZnSe/ZnS and acrylic acid, and acrylic acid accounts for The total weight of the quantum dot light-emitting layer is 0.005%, and the material of the cathode 150 is Ag.

A preparation method of a quantum dot light-emitting diode, comprising:

On the anode substrate, spin-coating a hole functional material to prepare a hole functional layer 120 to obtain a prefabricated device;

The obtained prefabricated device is placed in an atmosphere composed of _N2 or Ar and the vapor of the active material, and the content of acrylic acid in the total gas volume is 1%, the temperature of the gaseous environment is 40 ° C, and the total pressure is 1 MPa; The quantum dot light-emitting layer was prepared by the method, and the rotating speed was 3000 rpm/s.

Spin-coating electronic functional material on the surface of quantum dot light-emitting layer 130 to prepare electronic functional layer 140;

A cathode is vapor-deposited on the surface of the electronic functional layer 140 .

Example 2

The difference from Embodiment 1 is that in the process of preparing the red quantum dot light-emitting diode, the preparation method of the quantum dot light-emitting layer 130 is as follows:

According to the proportion of acrylic acid accounting for 0.005% of the total weight of acrylic acid and quantum dots, configure the mixed solution of active material and quantum dots;

The mixed solution of the active material and the quantum dots is spin-coated on the obtained prefabricated device to prepare the quantum dot light-emitting layer 130 .

The current efficiency (cd/A) of the red quantum dot light-emitting diode prepared in Test Example 1-2, the test method is as follows: scan from 0V to 7V with a 0.2V step, monitor the current with a Keithley source meter and an integrating sphere ( A) and brightness (nit/m ² ), the current efficiency test value is obtained.

The test results are shown in Table 1 below.

Table 1

电流效率(cd/A) Current efficiency (cd/A)	1天后 1 day later	3天后 3 days later	6天后 6 days later
实施例1 Example 1	8.6 8.6	14.6 14.6	18.7 18.7
实施例2 Example 2	7.6 7.6	10.2 10.2	14.1 14.1

As can be seen from Table 1, compared with the current efficiency of the first day, the current efficiency of the red quantum dot light-emitting diode provided in Example 1 was increased by 117% after 6 days; the current efficiency of the red quantum dot light-emitting diode provided by Example 2 was increased after 6 days. 85%. It can be seen that the positive aging efficiency of the red quantum dot light-emitting diode provided in the embodiment of the present application is significantly improved.

Example 3

A blue quantum dot light-emitting diode, a substrate, an anode located on the substrate, and a hole functional layer, a quantum dot light-emitting layer, an electronic functional layer and a cathode that are stacked in sequence, wherein the material of the substrate is silicon glass, The material of the anode is ITO, the material of the hole functional layer is TFB, the material of the quantum dot light-emitting layer includes quantum dots CdZnSe/ZnS and acrylic acid, the content of acrylic acid is 0.01%, and the material of the cathode is Ag.

A preparation method of a quantum dot light-emitting diode, comprising:

On the anode substrate, spin-coating the hole functional material to prepare a hole functional layer to obtain a prefabricated device;

The obtained prefabricated device is placed in an atmosphere composed of _N2 or Ar and the vapor of the active material, and the content of acrylic acid in the total gas volume is 1%, the temperature of the gaseous environment is 40 ° C, and the total pressure is 1 MPa; The quantum dot light-emitting layer was prepared by the method, and the rotating speed was 3000 rpm/s. Spin-coating electronic functional materials on the surface of the quantum dot light-emitting layer to prepare electronic functional layers;

A cathode is vapor-deposited on the surface of the electronic functional layer.

Example 4

The difference from Example 3 is that in the preparation method of the blue quantum dot light-emitting diode, the preparation method of the quantum dot light-emitting layer is:

A mixed solution of active material and quantum dots is spin-coated on the obtained prefabricated device to prepare a quantum dot light-emitting layer.

The current efficiency (cd/A) of the red quantum dot light-emitting diodes prepared in Test Example 3-4, the test method is as follows: scan from 0V to 7V with a step size of 0.2V, monitor the current with a Keithley source meter and an integrating sphere ( A) and brightness (nit/m ² ), the current efficiency test value is obtained.

The test results are shown in Table 1 below.

Table 2

电流效率(cd/A) Current efficiency (cd/A)	1天后 1 day later	3天后 3 days later	6天后 6 days later
实施例4 Example 4	4.8 4.8	6.3 6.3	9.0 9.0
实施例5 Example 5	4.2 4.2	5.8 5.8	7.6 7.6

As can be seen from Table 2, compared with the current efficiency of the first day, the current efficiency of the red quantum dot light-emitting diode provided in Example 3 was improved by 87.6% after 6 days; the current efficiency of the red quantum dot light-emitting diode provided by Example 4 was improved after 6 days. 80.9%. It can be seen that the positive aging efficiency of the red quantum dot light-emitting diode provided in the embodiment of the present application is significantly increased.

The above are only preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application shall be included in the protection scope of the present application. Inside.

Claims

A quantum dot light emitting diode is characterized in that it comprises an anode and a cathode arranged oppositely, a quantum dot light emitting layer arranged between the anode and the cathode, and a quantum dot light emitting layer arranged between the quantum dot light emitting layer and the cathode The electronic functional layer in between; wherein, the quantum dot light-emitting layer contains active materials, and the active materials are selected from organic hydrocarbons with at least one hydrogen atom substituted by carboxyl groups, carbon-carbon double bonds or carbon-carbon triple bonds or benzene rings. At least one of organic ester and unsaturated ketone.
The quantum dot light-emitting diode according to claim 1, wherein the active material is selected from the group consisting of acrylic acid, benzoic acid, methacrylic acid, 3-butenoic acid, crotonic acid, acetic acid, propionic acid, butyric acid, isobutyric acid at least one of acid, hydroxyethyl methacrylate, methyl methacrylate, butyl acrylate, trimethylol glycerate, and N-vinylpyrrolidone.
The quantum dot light-emitting diode according to claim 1, wherein the active material accounts for 0.0001%-1% of the total weight of the quantum dot light-emitting layer.
The quantum dot light-emitting diode according to claim 1, wherein the quantum dot light-emitting layer is composed of quantum dots and the active material.
The quantum dot light-emitting diode of claim 4, wherein the quantum dots are selected from the group consisting of II-VI compounds, III-V compounds, II-V compounds, III-VI compounds, and IV-VI compounds One or more of compounds, I-III-VI group compounds, II-IV-VI group compounds or group IV elements.
The quantum dot light-emitting diode according to claim 5, wherein the quantum dots are CdSe/ZnSe, CdSe/CdS, CdSe/CdS/ZnS, ZnCdSeS, ZnCdSeS/ZnS, ZnCdS/ZnS, ZnSe/ZnS one or more.
The quantum dot light emitting diode according to any one of claims 1 to 6, wherein the quantum dot light emitting diode further comprises a hole function layer disposed between the anode and the quantum dot light emitting layer.
A method for preparing a quantum dot light-emitting diode, comprising the following steps:

Provide a prefabricated device for preparing a quantum dot light-emitting layer;

The prefabricated device is placed in an atmosphere containing a gaseous active material, and a quantum dot light-emitting layer is prepared on the prefabricated device; wherein the gaseous active material is selected from organic hydrocarbons whose at least one hydrogen atom is substituted by a carboxyl group, a carbon-containing At least one of carbon double bond or carbon-carbon triple bond or organic ester of benzene ring and unsaturated ketone.
The method for manufacturing a quantum dot light-emitting diode according to claim 8, wherein the atmosphere is a mixed gaseous environment formed by a gaseous active material and at least one of oxygen, nitrogen, argon, and carbon dioxide.
The method for preparing a quantum dot light-emitting diode according to claim 8, wherein the active material is selected from the group consisting of acrylic acid, benzoic acid, methacrylic acid, 3-butenoic acid, crotonic acid, acetic acid, propionic acid, butyric acid , at least one of isobutyric acid, hydroxyethyl methacrylate, methyl methacrylate, butyl acrylate, trimethylol acrylate and N-vinylpyrrolidone.
The method for manufacturing a quantum dot light-emitting diode according to any one of claims 8 to 10, wherein the gaseous active material accounts for 0.1% to 50% of the total volume of the gas in the atmosphere.
The method for preparing a quantum dot light-emitting diode according to any one of claims 8 to 10, wherein the temperature of the gaseous environment is 25-150° C., and the total pressure is -0.1-4 MPa.
A method for preparing a quantum dot light-emitting diode, comprising the following steps:

A mixed solution of quantum dots and active materials is configured, wherein the active materials are selected from organic hydrocarbons with at least one hydrogen atom substituted by carboxyl groups, organic esters containing carbon-carbon double bonds or carbon-carbon triple bonds or benzene rings, and unsaturated ketones at least one of;

A prefabricated device on which a quantum dot light-emitting layer is to be prepared is provided, and the mixed solution is deposited on the prefabricated device to prepare a quantum dot light-emitting layer.
The method for preparing a quantum dot light-emitting diode according to claim 13, wherein, in the mixed solution, the active material accounts for 0.0001% to 1% of the total weight of the quantum dots and the active material.
The method for preparing a quantum dot light-emitting diode according to claim 13 or 14, wherein after the step of depositing the mixed solution on the prefabricated device, the method further comprises: drying at a temperature not higher than 150°C treatment to prepare the quantum dot light-emitting layer.
The method for preparing a quantum dot light-emitting diode according to claim 13 or 14, wherein the active material is selected from the group consisting of acrylic acid, benzoic acid, methacrylic acid, 3-butenoic acid, crotonic acid, acetic acid, propionic acid, At least one of butyric acid, isobutyric acid, hydroxyethyl methacrylate, methyl methacrylate, butyl acrylate, trimethylol acrylate, and N-vinylpyrrolidone.
The method for preparing a quantum dot light-emitting diode according to claim 13 or 14, wherein the quantum dots are selected from the group consisting of II-VI compounds, III-V compounds, II-V compounds, and III-VI compounds , one or more of IV-VI group compounds, I-III-VI group compounds, II-IV-VI group compounds or group IV elements.
The method for preparing a quantum dot light-emitting diode according to claim 17, wherein the quantum dots are CdSe/ZnSe, CdSe/CdS, CdSe/CdS/ZnS, ZnCdSeS, ZnCdSeS/ZnS, ZnCdS/ZnS, ZnSe/ One or more of ZnS.