CN113471378A - Quantum dot light-emitting device and preparation method thereof - Google Patents

Quantum dot light-emitting device and preparation method thereof Download PDF

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CN113471378A
CN113471378A CN202110747664.4A CN202110747664A CN113471378A CN 113471378 A CN113471378 A CN 113471378A CN 202110747664 A CN202110747664 A CN 202110747664A CN 113471378 A CN113471378 A CN 113471378A
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electron transport
quantum dot
layer
dot light
electronic transmission
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蒋畅
程陆玲
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Hefei Funa Technology Co ltd
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Hefei Funa Technology Co ltd
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    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K50/00—Organic light-emitting devices
    • H10K50/10—OLEDs or polymer light-emitting diodes [PLED]
    • H10K50/11—OLEDs or polymer light-emitting diodes [PLED] characterised by the electroluminescent [EL] layers
    • H10K50/115—OLEDs or polymer light-emitting diodes [PLED] characterised by the electroluminescent [EL] layers comprising active inorganic nanostructures, e.g. luminescent quantum dots
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K50/00—Organic light-emitting devices
    • H10K50/10—OLEDs or polymer light-emitting diodes [PLED]
    • H10K50/14—Carrier transporting layers
    • H10K50/16—Electron transporting layers
    • H10K50/166—Electron transporting layers comprising a multilayered structure
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K71/00—Manufacture or treatment specially adapted for the organic devices covered by this subclass

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Abstract

The application provides a quantum dot light-emitting device, and belongs to the technical field of quantum dot light-emitting. The quantum dot light-emitting device comprises a quantum dot light-emitting layer and an electron transmission layer which are stacked along a preset direction, wherein the electron transmission layer comprises a plurality of electron transmission structure layers which are stacked in the preset direction. In any two adjacent electronic transmission structure layers, the electronic transmission materials are the same, the average particle size of the electronic transmission materials in the electronic transmission structure layer far away from the quantum dot light emitting layer is A nm, the average particle size of the electronic transmission materials in the electronic transmission structure layer close to the quantum dot light emitting layer is Bnm, and A is larger than B. The problem of unbalance of electron and hole injection and exciton separation phenomenon can be improved, and thus the luminous efficiency of the quantum dot light-emitting device can be effectively improved.

Description

Quantum dot light-emitting device and preparation method thereof
Technical Field
The application relates to the technical field of quantum dot light emitting, in particular to a quantum dot light emitting device and a preparation method thereof.
Background
Quantum Dot Light Emitting Diodes (QLEDs) are display devices that emit different colors by electrical excitation with Quantum dots as the Light Emitting layer, and have the characteristics of self-height color threshold, long life, low power consumption, and the like.
In the operation of the quantum dot electroluminescent device, the processes of carrier injection, carrier transmission, exciton formation and recombination and the like are mainly included. At present, the mainstream method of the quantum dot electroluminescent device is to adopt materials such as ZnO and the like with high electron mobility as an electron transport layer material, so that the problem of unbalance of electron and hole injection exists, and the probability of exciton formation and recombination is reduced; in addition, the ZnO nano material has a higher work function, and spontaneous charge transfer phenomenon is easy to occur at the interface of the quantum dot and ZnO to cause exciton separation, so that the quantum dot causes exciton quenching due to the influence of charging. The efficiency of the device is reduced due to the reasons, and the luminous efficiency of the device is an important index of the quantum dot electroluminescent device, so that the luminous efficiency of the device is effectively improved, and the device has important significance.
Disclosure of Invention
The present application is directed to a quantum dot light emitting device and a method for fabricating the same, which can improve the problem of imbalance of electron and hole injection and the exciton separation phenomenon, thereby effectively improving the light emitting efficiency of the quantum dot light emitting device.
The embodiment of the application is realized as follows:
in a first aspect, an embodiment of the present application provides a quantum dot light emitting device, which includes a quantum dot light emitting layer and an electron transport layer stacked along a preset direction. The electronic transmission layer comprises a plurality of electronic transmission structure layers which are stacked in a preset direction; in any two adjacent electronic transmission structure layers, the electronic transmission materials are the same, the average particle size of the electronic transmission materials in the electronic transmission structure layer far away from the quantum dot light emitting layer is A nm, the average particle size of the electronic transmission materials in the electronic transmission structure layer close to the quantum dot light emitting layer is B nm, and A is larger than B.
In a second aspect, embodiments of the present application provide a method for manufacturing a quantum dot light emitting device as provided in the first aspect, where the method for manufacturing a quantum dot light emitting device includes, when an electron transport layer is formed on a surface of a quantum dot light emitting layer: firstly, preparing electron transport solutions by adopting a plurality of electron transport materials with different average particle sizes; and then, sequentially forming an electronic transmission structure layer along a preset direction by adopting corresponding electronic transmission solutions according to the sequence that the average particle size of the electronic transmission material is from small to large, so as to obtain a plurality of electronic transmission structure layers.
The quantum dot light-emitting device and the preparation method thereof have the advantages that:
according to the quantum dot light-emitting device, the electron transport layers are provided with the plurality of electron transport structure layers with different particle average sizes of the electron transport materials, and the average particle size of the electron transport materials in the electron transport structure layers closer to the light-emitting layer is smaller, so that the balance between electron injection and hole injection is facilitated; meanwhile, the electrode potential barrier between the electron transport layer and the cathode can be increased so as to be beneficial to balancing charges in the quantum dots; the light emitting efficiency of the quantum dot light emitting device can be effectively improved by improving the problem of unbalance of electron and hole injection and the exciton separation phenomenon.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained from the drawings without inventive effort.
Fig. 1 is a schematic structural diagram of a quantum dot light-emitting device according to an embodiment of the present disclosure;
fig. 2 is a schematic view of a package structure of a quantum dot light emitting device provided in an embodiment of the present application;
fig. 3 is a partial schematic flow chart of a manufacturing process of a quantum dot light emitting device according to an embodiment of the present disclosure.
Icon: 100-quantum dot light emitting devices; 110-an anode; 120-a hole injection layer; 130-a hole transport layer; 140-a quantum dot light emitting layer; 150-electron transport layer; 151-first electron transport structure layer; 152-a second electron transport structure layer; 160-a cathode; 200-packaging adhesive.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions of the embodiments of the present application will be clearly and completely described below. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.
In the present application, "and/or", such as "feature 1 and/or feature 2", refers to three cases that may be "feature 1" alone, "feature 2" alone, and "feature 1" plus "feature 2".
It is to be noted that, in the description of the present application, the meaning of "a plurality" of "one or more" means two or more, and the meaning of "a plurality" means two or more, unless otherwise specified; the range of "numerical value a to numerical value b" includes both values "a" and "b", and "unit of measure" in "numerical value a to numerical value b + unit of measure" represents both "unit of measure" of "numerical value a" and "numerical value b".
In addition, in the description of the present application, the terms "first", "second", and the like are used only for distinguishing the description, and are not intended to indicate or imply relative importance.
Referring to fig. 1 to 3, a quantum dot light emitting device 100 and a method for manufacturing the same according to an embodiment of the present disclosure are described in detail below.
In a first aspect, referring to fig. 1, an embodiment of the present disclosure provides a quantum dot light emitting device 100, where the quantum dot light emitting device 100 includes a quantum dot light emitting layer 140 and an electron transport layer 150 stacked along a predetermined direction. Wherein the predetermined direction is a thickness direction of the quantum dot light emitting device 100, which is shown as a direction in fig. 1.
The electron transport layer 150 includes a plurality of electron transport structure layers stacked in a preset direction. In any two adjacent electron transport structure layers, the electron transport material is the same, in other words, the electron transport material is the same in the whole electron transport layer 150.
In any two adjacent electronic transmission structure layers, the average particle size of the electronic transmission material in the electronic transmission structure layer far away from the quantum dot light emitting layer 140 is A nm, the average particle size of the electronic transmission material in the electronic transmission structure layer close to the quantum dot light emitting layer 140 is B nm, and A is larger than B. Wherein, nm in A nm and B nm refers to the average size unit of the particles of the electron transport material is nanometer, and A and B refer to the nanometer numerical value of the average size of the particles of the electron transport material. In other words, in any two adjacent electron transport structure layers, the average particle size of the electron transport material in the electron transport structure layer far from the quantum dot light emitting layer 140 is larger, and the average particle size of the electron transport material in the electron transport structure layer near the quantum dot light emitting layer 140 is smaller.
In the embodiment of the present application, the structure of the qd-led device 100 may be configured according to the formula in the art. As an example, continuing to refer to fig. 1, the quantum dot light emitting device 100 includes an anode 110, a hole injection layer 120, a hole transport layer 130, a quantum dot light emitting layer 140, an electron transport layer 150, and a cathode 160, which are sequentially stacked along a predetermined direction.
In the prior art, the band structure is usually adjusted by doping in the electron transport layer 150, but the electron mobility is significantly reduced due to the reduction of oxygen vacancies after doping. The quantum dot light-emitting device 100 provided by the application adjusts a plurality of electron transport structure layers with different average particle sizes, which are provided with electron transport materials in the electron transport layer 150, and the method can effectively avoid the problem of reduction of oxygen vacancies caused by doping.
In the present application, in the electron transport structure layer in which the average size of the particles of the electron transport material is large, since the electron mobility of the electron transport material having a large average size of the particles is relatively low as compared with the electron transport material having a small average size of the particles, the balance of electron and hole injection is facilitated. An electron transport structure layer with a smaller average particle size of an electron transport material is additionally arranged on one side close to the quantum dot light emitting layer 140, and the electron transport material with a smaller average particle size has an increased conduction band position and a decreased valence band position relative to the electron transport material with a larger average particle size, so that the forbidden band width is increased, and therefore, the electrode barrier between the electron transport layer 150 and the cathode 160 can be increased, the electron transport can be delayed, the leakage current can be reduced, and the balance of charges in quantum dots in the quantum dot light emitting layer 140 is facilitated; meanwhile, the small-sized electron transport material has a deeper HOMO energy level, and forms a larger energy level barrier with the quantum dot light emitting layer 140, so that holes can be effectively prevented from being transported to the electron transport layer 150, and spontaneous charge transfer at the interface between the quantum dot and the electron transport layer 150 is reduced.
In the application, by using a large-sized electron transport material, the balance of electron and hole injection can be effectively improved under the condition of properly reducing the electron mobility; and reduces spontaneous charge transfer at the interface of the quantum dot and the electron transport layer 150 by using a small-sized electron transport material, and thus can effectively improve the light emitting efficiency of the quantum dot light emitting device 100.
It is understood that in the embodiments of the present application, the number of the electron transport structure layers may be selected according to the average size gradient of the particles of the electron transport material, the material of the device mechanism layer, and the like, for example, but not limited to, two, three, four, or more.
Considering that when two electronic transmission structure layers are arranged, the electronic transmission material with different average particle sizes can be provided, and the preparation is convenient.
With continued reference to fig. 1, in some exemplary embodiments, the electron transport layer 150 is composed of a first electron transport structure layer 151 and a second electron transport structure layer 152, the first electron transport structure layer 151 is formed on the surface of the quantum dot light emitting layer 140, and the second electron transport structure layer 152 is formed on a side surface of the first electron transport structure layer 151 away from the quantum dot light emitting layer 140. The average particle size of the electron transport material in the second electron transport structure layer 152 is a nm, the average particle size of the electron transport material in the first electron transport structure layer 151 is B nm, and the average particle size of the electron transport material in the second electron transport structure layer 152 is larger than the average particle size of the electron transport material in the first electron transport structure layer 151.
It is contemplated that an electron transport material having a certain average particle size in the electron transport layer 150 may be advantageous to balance the injection of electrons and holes and the electrode barrier requirements. In addition, when the average particle sizes of the electron transport materials in two adjacent electron transport structure layers have proper difference values, the requirements of electron mobility and an electrode barrier can be better considered, and if the difference value of A and B is too small, the adjustment requirement of the electrode barrier cannot be well met; if the difference between a and B is too large, electron transport between the electron transport layers 150 is affected.
Further, the average particle size of the electron transport material in the second electron transport structure layer 152 is 4-10 nm, such as but not limited to any one of 4nm, 5nm, 6nm, 7nm, 8nm, 9nm and 10nm or a range between any two of them; the average particle size of the electron transport material in the first electron transport structure layer 151 is 1 to 6nm, such as but not limited to any one of 1nm, 2nm, 3nm, 4nm, 5nm and 6nm or a range between any two of them.
Illustratively, in any two adjacent electronic transmission structure layers, the difference between A and B is 2-4 nm, such as but not limited to any one of 2nm, 3nm and 4nm or the range between any two of them.
Considering that ZnO has a large electron mobility, and when ZnO is used as an electron transport material of the electron transport layer 150 in the embodiments of the present application, ZnO particles distributed in different electron transport structure layers cooperate with each other, so that the effects of improving the balance between electron and hole injection and reducing spontaneous charge transfer at the interface between the quantum dot and the electron transport layer 150 can be better exerted.
In some exemplary embodiments, the electron transport material in the electron transport layer 150 is ZnO particles.
It is understood that in the embodiments of the present application, the kind of the electron transport material may be selected according to the kind of materials known in the art, and is not limited to ZnO particles, such as but not limited to TiO2、ZrO2、SnO2、WO3、Ta2O3、HfO3And Al2O3One or more of (a).
In addition, in the embodiment of the present application, the materials of the anode 110, the hole injection layer 120, the hole transport layer 130, the quantum dot light emitting layer 140, and the cathode 160 may be selected according to the kind and standard well known in the art.
As cadmium-containing quantum dots are classified as high-risk substances and carcinogenic substances by the european union, diodes using semiconductor cadmium-free quantum dots as light emitting layers are receiving more and more attention. In consideration of the security of the quantum dot material, the quantum dot light-emitting device 100 provided in the embodiment of the present application is exemplarily a cadmium-free quantum dot light-emitting device 100, wherein the quantum dot material of the quantum dot light-emitting layer 140 is a cadmium-free quantum dot.
It is understood that, in the embodiments of the present application, the kind of the cadmium-free quantum dot is not particularly limited, and may be selected according to the kind and requirements known in the art.
In some possible embodiments, the cadmium-free quantum dots are one or more of group IIB-VA compounds, group IIB-VIA compounds, group IIIA-VA compounds, group IIIA-VIA compounds, group IVA-VIA compounds, group IB-IIIA-VIA compounds, and group IIB-IV-VIA compounds or group IVA simple substances.
In the examples of the present application, the group IIB-VA compound means a compound composed of a group IIB element and a group VA element, the group IB-III-VIA compound means a compound composed of a group IB element, a group IIIA element and a group VIA element, and so on.
Optionally, the cadmium-free quantum dots are ZnSe, ZnS, ZnTe, InP, InAs, CuInS2、AgInS2C, Si and Ge.
Adaptively, in the quantum dot light emitting layer 140 using the oil-soluble quantum dot, the ligand on the surface of the quantum dot is one or more of oleic acid (OA for short), oleylamine (OAm for short), octylamine, trioctylphosphine (TOP for short), trioctylphosphine oxide (TOPO for short), octadecylphosphonic acid (ODPA for short) and tetradecylphosphonic acid (TDPA for short).
The quantum dot light-emitting device 100 provided in the embodiment of the present application may also be packaged according to a manner known in the art. Referring to fig. 2, a plurality of quantum dot light emitting devices 100 are packaged by using sealant, and exemplarily, four quantum dot light emitting devices 100 are distributed in a rectangular shape, and are packaged by using a packaging sealant 200.
In a second aspect, an embodiment of the present application provides a method for manufacturing a quantum dot light emitting device 100 as provided in the first aspect, where the method for manufacturing the quantum dot light emitting device includes, when forming an electron transport layer 150 on a surface of a quantum dot light emitting layer 140: firstly, a plurality of electron transport materials with different average particle sizes are adopted to respectively prepare electron transport solutions. Then, sequentially forming an electronic transmission structure layer along a preset direction by adopting corresponding electronic transmission solutions according to the sequence that the average particle size of the electronic transmission material is from small to large to obtain a plurality of electronic transmission structure layers; that is, an electron transport structure layer is formed on the surface of the quantum dot light emitting layer 140 by using an electron transport solution with a smaller average particle size of an electron transport material, and a new electron transport structure layer is formed on the formed electron transport structure layer by using an electron transport solution with a larger average particle size of an electron transport material until a plurality of electron transport structure layers with a desired number are obtained.
Considering that the thin films are formed by a spin coating mode, the stability of the surface morphology of the thin films can be well ensured. In the fabrication process of the quantum dot light emitting device 100, when the hole injection layer 120, the hole transport layer 130, the quantum dot light emitting layer 140, and the electron transport layer 150 are formed, each structural layer is generally formed by a spin coating process.
In some exemplary embodiments, a method of manufacturing the quantum dot light emitting device 100 includes:
step S1: on the cleaned surface of the anode 110, a hole injection layer 120 is formed by spin-coating and then annealing.
Step S2: on the surface of the hole injection layer 120 formed in step S1, the hole transport layer 130 is formed by annealing after spin coating.
Step S3: on the surface of the hole transport layer 130 formed in step S2, the quantum dot light emitting layer 140 is formed by annealing after spin coating.
Step S4: the first electron transport structure layer 151 is formed by annealing after spin coating on the surface of the quantum dot light emitting layer 140 formed in step S3.
Step S5: on the surface of the first electron transport structure layer 151 formed in step S4, the second electron transport structure layer 152 is formed by annealing after spin coating.
Step S6: on the surface of the second electron transport structure layer 152 formed in step S5, the cathode 160 is formed by thermal evaporation.
Considering that in order to preferably realize spin coating of the electron transport solution to form an electron transport structure layer having a stable surface morphology, the electron transport material in the electron transport solution needs to have a suitable concentration, and the electron transport solution needs to have a suitable solvent species.
Regarding the concentration of the electron-transporting material in the electron-transporting solution, as an example of an aspect, the concentration of the electron-transporting material in the electron-transporting solution is 0.1 to 100mg/mL, such as, but not limited to, any one of 0.1mg/mL, 0.5mg/mL, 1mg/mL, 5mg/mL, 10mg/mL, 15mg/mL, 20mg/mL, 30mg/mL, 40mg/mL, 50mg/mL, 60mg/mL, 70mg/mL, 80mg/mL, 90mg/mL, and 10mg/mL, or a range between any two thereof.
As for the solvent in the electron transport solution, as an example of another aspect, the solvent in the electron transport solution is one or more of methanol, ethanol, propanol, butanol, petroleum ether, diethyl ether, n-butyl ether, octane, hexane, heptane, acetone, ethyl acetate, toluene, chlorobenzene, chloroform, dichloromethane, and chlorobenzene; optionally, the solvent is ethanol.
It is understood that in the examples of the present application, in formulating an electron transport solution, a plurality of electron transport materials having different average particle sizes may be directly selected for products having a specific average particle size; can also be used after being manufactured so as to ensure that the electron transport material with the specific particle average size requirement is obtained and is beneficial to ensuring the purity of the electron transport material.
Referring to fig. 3, in some possible embodiments, before preparing the electron transport solution using a plurality of electron transport materials having different average particle sizes, the method further includes: a plurality of electron transport materials with different average particle sizes are prepared by a sol-gel method. After the electron transport materials with different average particle sizes are prepared, the obtained electron transport materials with different average particle sizes are respectively prepared into electron transport solutions, and then different electron transport solutions are sequentially formed into different electron transport structure layers according to a certain sequence when the quantum dot light-emitting device 100 is prepared.
When different types of electron transport materials are prepared, different reaction raw materials can be selected according to the types of the electron transport materials. As an example, when the electron transport material in the electron transport layer 150 is ZnO particles, the sol-gel method includes: a solution of zinc acetate in dimethyl sulfoxide (DMSO) was reacted with tetramethylammonium hydroxide and then washed with an organic reagent.
In order to achieve better cleaning of the ZnO particles, the organic agent for cleaning is one or more of alcohol, ethanol, propanol, butanol, petroleum ether, diethyl ether, n-butyl ether, octane, hexane, heptane, acetone, ethyl acetate, toluene, chlorobenzene, chloroform, dichloromethane and chlorobenzene, for example, ethyl acetate and heptane.
Considering that when the electron transport material is prepared by adopting a sol-gel method, the average size of particles of the electron transport material can be effectively regulated and controlled by regulating metal ions in a precursor and the alkalinity of a solution within a certain range.
Further, in the precursor of the sol-gel method, Zn2+With OH-In a molar ratio of 0.1 to 10, and adding Zn2+With OH-The molar ratio of (A) to (B) is adjusted within the above range, and an electron transport material having an average particle size of 1 to 10nm can be efficiently produced.
The features and properties of the present application are described in further detail below with reference to examples.
Example 1
A method for preparing a quantum dot light-emitting device comprises the following steps:
(1) preparation of ZnO particles of different average particle size:
gradually dropwise adding a 3M ethanol solution of tetramethylammonium hydroxide into a 1.4M solution of zinc acetate dimethyl sulfoxide at room temperature, stirring for 30min, and washing with ethyl acetate and heptane to obtain a first part of ZnO particles with an average size of 4 nm.
Gradually dropwise adding a tetramethylammonium hydroxide ethanol solution with the concentration of 3M into a zinc acetate dimethyl sulfoxide solution with the concentration of 3.8M at room temperature, stirring for 30min, and cleaning with ethyl acetate and heptane to obtain a second part of ZnO particles, wherein the average size of the second part of ZnO particles is 7 nm.
(2) Preparing electron transport solutions with different ZnO particle average sizes:
the first portion of ZnO particles was dissolved in ethanol to prepare a first electron transport solution with a ZnO particle concentration of 20 mg/mL.
And dissolving the second part of ZnO particles in ethanol to prepare a second part of electron transport solution with the concentration of the ZnO particles being 20 mg/mL.
(3) Preparing a quantum dot light-emitting device:
an ITO glass substrate is used as an anode.
The filtered PEDPOT: PSS (poly 3, 4-ethylenedioxythiophene: polystyrene sulfonate) solution was spin-coated on the cleaned anode surface at 3500rpm for 40s, followed by annealing at 150 ℃ for 20min to form a hole injection layer.
A PVK chlorobenzene solution with PVK (polyvinyl carbazole) concentration of 6mg/ml is subjected to spin coating for 40s at the rotation speed of 1800rpm on the surface of the hole injection layer, and then annealing is carried out for 10min at 110 ℃ to form a hole transport layer.
And (2) adopting InP/ZnSe/ZnS red quantum dots, spin-coating a quantum dot octane solution with the quantum dot concentration of 30mg/ml on the surface of the hole transport layer at the rotating speed of 2000rpm for 60s, and then annealing to form a quantum dot light-emitting layer.
And spin-coating the first electron transport solution on the surface of the hole transport layer at 2000rpm for 60s, and then annealing to form a first electron transport structure layer.
And spin-coating a second electron transport solution on the surface of the hole transport layer at 2000rpm for 30s, and then annealing to form a second electron transport structure layer.
At 2X 104A high vacuum of Pa is used to deposit a 150nm thick aluminum electrode as a cathode by thermal evaporation through a mask.
In the present embodiment, the area of the quantum dot light emitting device is 4cm2The structural layers are configured according to the standard of AI 4083.
Example 2
A method for producing a quantum dot light-emitting device, which is different from embodiment 1 only in that:
the quantum dots used in the quantum dot solution are different in kind. In the embodiment, the quantum dots are InP/ZnS green quantum dots.
Example 3
A method for producing a quantum dot light-emitting device, which is different from embodiment 1 only in that:
the average sizes of the first and second portions of ZnO particles were different from example 1, respectively. In this example, the first portion of ZnO particles had an average size of 1nm and the second portion of ZnO particles had an average size of 4 nm; and the difference between the two is 3nm and is within the range of 2-4 nm.
Example 4
A method for producing a quantum dot light-emitting device, which is different from embodiment 1 only in that:
the average sizes of the first and second portions of ZnO particles were different from example 1, respectively. In this example, the first portion of ZnO particles had an average size of 6nm and the second portion of ZnO particles had an average size of 10 nm; the difference between the two is 4nm and is within the range of 2-4 nm.
Example 5
A method for producing a quantum dot light-emitting device, which is different from embodiment 1 only in that:
the difference in the average size of the first and second portions of ZnO particles was different from example 1. In this example, the first portion of ZnO particles had an average size of 5nm and the second portion of ZnO particles had an average size of 6 nm; the difference between the two is 1nm and is lower than the lower limit of the range of 2-4 nm.
Example 6
A method for producing a quantum dot light-emitting device, which is different from embodiment 1 only in that:
the difference in the average size of the first and second portions of ZnO particles was different from example 1. In this example, the first portion of ZnO particles had an average size of 3nm and the second portion of ZnO particles had an average size of 8 nm; the difference between the two is 5nm and is higher than the upper limit of the range of 2-4 nm.
Example 7
A method for producing a quantum dot light-emitting device, which is different from embodiment 1 only in that:
the kind of the electron transport material was different from that of example 1. In this embodiment, the electron transport material is TiO2。
Example 8
A method for producing a quantum dot light-emitting device, which is different from embodiment 1 only in that:
the kind of the electron transport material was different from that of example 1. In this embodiment, the kind of the electron transport material is SnO2。
Comparative example 1
A method for producing a quantum dot light-emitting device, which is different from embodiment 1 only in that:
the first electron transport structure layer is not provided.
Comparative example 2
A method for producing a quantum dot light-emitting device, which is different from embodiment 2 only in that:
the first electron transport structure layer is not provided.
Comparative example 3
A method for producing a quantum dot light-emitting device, which is different from embodiment 1 only in that:
the first electronic transmission structure layer and the second electronic transmission structure layer are arranged in the opposite order.
Comparative example 4
A method for producing a quantum dot light-emitting device, which is different from embodiment 2 only in that:
the first electronic transmission structure layer and the second electronic transmission structure layer are arranged in the opposite order.
Comparative example 5
A method for producing a quantum dot light-emitting device, which is different from embodiment 1 only in that:
the first and second portions of ZnO particles were formulated into the same composite electron transport solution in which the concentration of the first portion of ZnO particles was 20mg/mL and the concentration of the second portion of ZnO particles was 20 mg/mL.
After the quantum dot light-emitting layer is formed, the composite electron transport solution is coated on the surface of the quantum dot light-emitting layer in a spin mode for 90s, and an electron transport layer of a composite structure with the first ZnO particles and the second ZnO particles dispersed at the same time is formed.
Comparative example 6
A method for producing a quantum dot light-emitting device, which is different from embodiment 2 only in that:
the first and second portions of ZnO particles were formulated into the same composite electron transport solution in which the concentration of the first portion of ZnO particles was 20mg/mL and the concentration of the second portion of ZnO particles was 20 mg/mL.
After the quantum dot light-emitting layer is formed, the composite electron transport solution is coated on the surface of the quantum dot light-emitting layer in a spin mode for 90s, and an electron transport layer of a composite structure with the first ZnO particles and the second ZnO particles dispersed at the same time is formed.
Test examples
The average size of particles of the electron transport material in each electron transport structure layer in each example and comparative example was counted, and the External Quantum Efficiency (EQE) of the quantum dot light emitting device of each example and comparative example was examined.
The results are shown in table 1:
TABLE 1 efficiency of Quantum dot light emitting devices
Figure BDA0003144901070000101
According to the analysis of Table 1:
according to the comparison between examples 1 to 2 and comparative examples 1 to 2 and 5 to 6, in the examples of the present application, the electron transport layer is provided as a composite structure having a plurality of electron transport structure layers and the average particle size of the electron transport material in the electron transport structure layers is reduced in a direction close to the quantum dot light emitting layer, and the device efficiency is significantly improved as compared with the comparative example in which only one electron transport structure layer is provided.
As can be seen from comparison between examples 1 to 2 and comparative examples 3 to 4, in the case where the electron transport structure layers are arranged so that the sizes of the electron transport materials in each layer are different, it is advantageous to significantly improve the device efficiency to arrange the plurality of electron transport structure layers so that the average particle size of the electron transport materials in the electron transport structure layers closer to the light emitting layer is smaller.
According to the comparison between the embodiments 1 to 4 and the embodiments 5 to 6, the electronic transmission layer is set to be a composite structure which is provided with a plurality of electronic transmission structure layers and the average particle size of the electronic transmission material in the electronic transmission structure layers is reduced in the direction close to the quantum dot light emitting layer, the size difference between two adjacent electronic transmission structure layers is controlled within the range of 2 to 4nm, and the improvement effect on the device efficiency is better.
According to comparison between the embodiment 1 and the embodiments 7 to 8, the ZnO is adopted as the electron transmission material, so that the electron transmission effect of the electron transmission layer is better, and the efficiency of the device is obviously higher.
The embodiments described above are some, but not all embodiments of the present application. The detailed description of the embodiments of the present application is not intended to limit the scope of the claimed application, but is merely representative of selected embodiments of the application. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

Claims (10)

1. A quantum dot light-emitting device comprises a quantum dot light-emitting layer and an electron transmission layer which are stacked along a preset direction, and is characterized in that the electron transmission layer comprises a plurality of electron transmission structure layers which are stacked along the preset direction; in any two adjacent electronic transmission structure layers, the electronic transmission materials are the same, the average particle size of the electronic transmission materials in the electronic transmission structure layers far away from the quantum dot light emitting layer is A nm, the average particle size of the electronic transmission materials in the electronic transmission structure layers close to the quantum dot light emitting layer is B nm, and A is larger than B.
2. The quantum dot light-emitting device according to claim 1, wherein the electron transport layer is composed of a first electron transport structure layer and a second electron transport structure layer, the first electron transport structure layer is formed on the surface of the quantum dot light-emitting layer, the second electron transport structure layer is formed on the surface of the first electron transport structure layer, which is far away from the quantum dot light-emitting layer, and the average particle size of the electron transport material in the second electron transport structure layer is larger than that of the electron transport material in the first electron transport structure layer.
3. The quantum dot light-emitting device according to claim 2, wherein the average particle size of the electron transport material in the second electron transport structure layer is 4-10 nm, and the average particle size of the electron transport material in the first electron transport structure layer is 1-6 nm.
4. The quantum dot light-emitting device according to any one of claims 1 to 3, wherein in any two adjacent electron transport structure layers, the difference between A and B is 2 to 4 nm.
5. The quantum dot light-emitting device according to any one of claims 1 to 3, wherein the electron transport material in the electron transport layer is ZnO particles.
6. A method for preparing a quantum dot light-emitting device according to any one of claims 1 to 5, wherein the forming of the electron transport layer on the surface of the quantum dot light-emitting layer comprises:
firstly, preparing electron transport solutions by adopting a plurality of electron transport materials with different average particle sizes;
and then sequentially forming one electronic transmission structure layer along the preset direction by adopting the corresponding electronic transmission solution according to the sequence that the average particle size of the electronic transmission material is from small to large, so as to obtain a plurality of electronic transmission structure layers.
7. The method according to claim 6, wherein the concentration of the electron transport material in the electron transport solution is 0.1 to 100 mg/mL.
8. The method according to claim 6, wherein the solvent in the electron transport solution is one or more selected from methanol, ethanol, propanol, butanol, petroleum ether, diethyl ether, n-butyl ether, octane, hexane, heptane, acetone, ethyl acetate, toluene, chlorobenzene, chloroform, dichloromethane, and chlorobenzene;
optionally, the solvent is ethanol.
9. The method according to any one of claims 6 to 8, wherein before preparing the electron transport solution using the plurality of electron transport materials having different average particle sizes, the method further comprises: preparing a plurality of electron transport materials with different average particle sizes by a sol-gel method;
optionally, the electron transport material in the electron transport layer is ZnO particles, and the sol-gel method includes: reacting dimethyl sulfoxide solution of zinc acetate with tetramethyl ammonium hydroxide, and then cleaning by adopting an organic reagent.
10. The production method according to claim 9, wherein Zn is contained in the precursor of the sol-gel method2+With OH-The molar ratio of (A) to (B) is 0.1 to 10.
CN202110747664.4A 2021-07-02 2021-07-02 Quantum dot light-emitting device and preparation method thereof Pending CN113471378A (en)

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109643766A (en) * 2016-09-13 2019-04-16 罗门哈斯电子材料韩国有限公司 Organnic electroluminescent device comprising electron buffer layer and electron transfer layer
CN109980097A (en) * 2017-12-27 2019-07-05 Tcl集团股份有限公司 A kind of preparation method of film and QLED device
CN109994629A (en) * 2017-12-29 2019-07-09 Tcl集团股份有限公司 Laminated film and its preparation method and application
CN110571343A (en) * 2019-09-09 2019-12-13 合肥鑫晟光电科技有限公司 light emitting diode device, preparation method thereof and display substrate
CN111384279A (en) * 2018-12-29 2020-07-07 Tcl集团股份有限公司 Quantum dot light-emitting diode
CN111384255A (en) * 2018-12-27 2020-07-07 Tcl集团股份有限公司 Quantum dot light-emitting diode and preparation method thereof

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109643766A (en) * 2016-09-13 2019-04-16 罗门哈斯电子材料韩国有限公司 Organnic electroluminescent device comprising electron buffer layer and electron transfer layer
CN109980097A (en) * 2017-12-27 2019-07-05 Tcl集团股份有限公司 A kind of preparation method of film and QLED device
CN109994629A (en) * 2017-12-29 2019-07-09 Tcl集团股份有限公司 Laminated film and its preparation method and application
CN111384255A (en) * 2018-12-27 2020-07-07 Tcl集团股份有限公司 Quantum dot light-emitting diode and preparation method thereof
CN111384279A (en) * 2018-12-29 2020-07-07 Tcl集团股份有限公司 Quantum dot light-emitting diode
CN110571343A (en) * 2019-09-09 2019-12-13 合肥鑫晟光电科技有限公司 light emitting diode device, preparation method thereof and display substrate

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Application publication date: 20211001